JP6376846B2 - Manufacturing method of developing device frame - Google Patents

Description

  The present invention relates to a method for producing a developing container used in an image forming apparatus such as a copying machine, a printer, and a facsimile machine using an electrophotographic method or an electrostatic recording method, and further a developer container, a developing device, a process cartridge, and an image. The present invention relates to a forming apparatus.

  2. Description of the Related Art Conventionally, for example, in an image forming apparatus using an electrophotographic system, development is performed by supplying a developer to an electrostatic latent image formed on an electrophotographic photosensitive member (photosensitive member) as an image carrier to form a developer image. A device is provided. In recent years, a developing cartridge or a process cartridge in which a developing device is detachable from an apparatus main body of an image forming apparatus alone or together with other process means has been widely used.

  According to the cartridge system in which the developing cartridge and the process cartridge (hereinafter, also simply referred to as “cartridge”) are detachable from the main body of the image forming apparatus, it is easy to replenish the developer and perform other maintenance work. It can be carried out.

  In the cartridge system, generally, when the developer in the developer container of the developing device runs out, an operator such as a user or a serviceman replaces the cartridge or replenishes the developer, so that the image forming apparatus is again An image can be formed. For this reason, the cartridge type image forming apparatus has a detecting unit for detecting the amount of developer (remaining amount) in order to detect when the developer has been consumed and notify the user of the cartridge replacement time. It is common to have.

  As this detection means, as disclosed in Patent Document 1, a pair of input-side and output-side electrodes is provided, and a capacitance that detects the amount of developer by measuring the capacitance between both electrodes. There are detection methods. As the electrode, an antenna member generally used as a plate-like member (SUS sheet metal or the like) made of metal is used.

  Further, as described in Patent Document 2, in a developing device in which an AC voltage is applied to the developer carrying member, the developer carrying member is used as an input side electrode, and a capacitance detecting member serving as an output side electrode is provided. It can be provided at a location facing the developer carrier in the developing device. As this capacitance detection member, an antenna member generally used as a plate-like member (SUS sheet metal or the like) made of metal is used.

  The capacitance between the electrodes (between the antenna members or between the developer carrying member and the antenna member) in the capacitance detection method varies depending on the amount of the developer composed of insulating toner or the like. That is, if the space between the electrodes is filled with developer, the capacitance between the electrodes increases, and as the developer decreases, the ratio of air to the space between the electrodes increases and the capacitance decreases. Go. Therefore, if the relationship between the capacitance between the electrodes and the amount of developer is obtained in advance, the amount of developer can be detected by measuring the capacitance.

  However, if an electrode plate such as SUS sheet metal as described above is used as the antenna member, the component cost tends to be relatively high. Therefore, for example, in order to improve the detection accuracy of the amount of developer, or to be able to detect the remaining amount of developer sequentially from an earlier stage of use, the antenna member is increased or the number thereof is increased. Then, the cost of the developer container or the like tends to increase.

  By the way, Patent Document 3 discloses a method of affixing an antenna member with a double-sided tape to a frame forming a developer container of a developing device. In Patent Document 3, a process such as vapor deposition or printing is directly performed on the frame to form a conductive paint layer or a vapor deposition layer provided directly on the frame, or a conductive resin is molded in two colors. However, a detailed description is not disclosed.

  In Patent Document 4, an electrode layer is formed by applying a coating solution in which carbon black fine particles are dispersed in an appropriate amount in a solution obtained by blending urethane resin and polyvinyl chloride resin on a base sheet of a sheet member, and thermally curing the coating solution. Is disclosed.

JP 2001-117346 A JP 2003-248371 A JP 2002-40906 A JP-A-8-15975

  However, as described above, the method of adhering the antenna member to the frame with double-sided tape or vapor deposition or printing on the frame requires a process for processing the frame after the frame is formed. As a result, the manufacturing process tends to be complicated.

Therefore, an object of the present invention is to provide a manufacturing method that can easily manufacture a frame of a developing device in which the amount of developer is detected by a capacitance detection method.

  The present invention also provides a developing container, a developing device, and a process cartridge capable of improving the detection accuracy when the amount of developer is detected by a capacitance detection method using a conductive resin member as an electrode. Objective.

Therefore, the present invention includes a frame that forms a developer accommodating portion, a first electrode, and a second electrode that is formed integrally with the frame, and the first electrode In the method for manufacturing the frame body integrated with the second electrode used in a developing device that performs output in accordance with the capacitance between the second electrode and the second electrode, a metal for forming the frame body a process you positioned to hold the conductive resin sheet which is the second electrode in a mold, of the conductive resin sheet to a surface of the mold forming the surface of the housing part side of the developer of the frame Contacting the surfaces, and holding and positioning the first region of the conductive resin sheet in the holding region of the mold by a holding unit ; and forming the frame body on the mold holding the conductive resin sheet a step of injecting resin from the gate provided in the mold, curing the resin Have a, and forming the frame member wherein the conductive resin sheet is fixed relates widthwise direction of the frame body, the conductive resin sheet has a one end and the other end, the other end Is located farther from the first region than the one end, and the other end is downstream of the one end in the direction in which the resin injected from the gate spreads in the mold. A method for manufacturing the frame body is provided, wherein the frame body is located on a side .
According to another aspect of the present invention, the frame includes a frame that constitutes a developer accommodating portion, a first electrode, and a second electrode that is integrally formed with the frame, and the first electrode In the manufacturing method of the frame body in which the second electrode used in a developing device that performs output according to the capacitance between the electrode and the second electrode is integrated, the frame body is formed A step of holding and positioning the conductive resin sheet as the second electrode on a mold for forming the surface of the mold that forms a surface of the frame on the developer accommodating portion side Contacting the surface of the sheet and holding and positioning the conductive resin sheet in a holding region of the mold by holding means; and the resin forming the frame body on the mold holding the conductive resin sheet Injecting from the gate provided in the mold, and curing the resin before Forming the frame to which the conductive resin sheet is fixed, and the holding means holds a region on one end side in the short direction of the frame of the conductive resin sheet in the holding region, The other end side in the short direction facing the one end side is not held in the holding region, and is farther from the gate than the one end side in the short direction. A method of manufacturing a body is provided.
According to still another aspect of the present invention, the apparatus includes a frame that forms a developer accommodating portion, a first electrode, and a second electrode that is integrally formed with the frame, In the manufacturing method of the frame body in which the second electrode used in a developing device that performs output according to the capacitance between the first electrode and the second electrode is integrated, the frame body is molded A step of holding and positioning the conductive resin sheet as the second electrode on a mold for forming the conductive material on the surface of the mold that forms a surface of the frame on the developer accommodating portion side. A step of bringing the surface of the resin sheet into contact and holding and positioning the first region of the conductive resin sheet in the holding region of the mold by a holding unit; and the frame body on the die holding the conductive resin sheet A step of injecting a resin for forming a resin from a gate provided in the mold; and And forming the frame body to which the conductive resin sheet is fixed, and with respect to the short direction of the frame body, the conductive resin sheet has one end and the other end. The frame, wherein the other end is located farther from the first region than the one end, and the other end is further away from the gate than the first region. A method of manufacturing a body is provided.

According to another aspect of the present invention, there is provided a developer container for containing a developer, the antenna member for detecting a developer amount using a capacitance, and the antenna member Is a conductive resin member, and a developer container is provided in which the resistance of the conductive resin member is 10 ³ Ω or more and 10 ⁵ Ω or less.

  According to another aspect of the present invention, there is provided a frame that forms a developer accommodating portion, a first electrode, and a surface that is disposed on a surface of the frame and faces the first electrode. A developer container in which the amount of developer in the housing portion is detected based on a capacitance between the first electrode and the second electrode; The electrode is composed of a conductive resin member, and when viewed in the axial direction of the first electrode, the closest point between the first electrode and the second electrode on the second electrode is: The second electrode is located at a position other than the end of the second electrode, the second electrode has at least one convex portion projecting toward the first electrode, and the nearest point is at the convex portion. A developer container is provided.

  According to another aspect of the present invention, there is provided a developing device, a process cartridge, and an image forming apparatus provided with the developing container of the present invention.

According to the frame manufacturing method of the present invention, it is possible to easily manufacture a frame of a developing device in which the amount of developer is detected by a capacitance detection method. Further, according to the developing container, the developing device, and the process cartridge of the present invention, it is possible to improve the detection accuracy when the amount of developer is detected by the electrostatic capacitance detection method using the conductive resin member as an electrode.

1 is a schematic cross-sectional view of an image forming apparatus according to a first embodiment. It is a schematic sectional drawing of the process cartridge of 1st Embodiment. It is a schematic sectional drawing of the image development apparatus of 1st Embodiment. FIG. 5 is a graph showing the relationship between the amount of toner and capacitance according to the first embodiment. It is a schematic diagram for demonstrating the manufacturing process of the image development frame of 1st Embodiment. It is sectional drawing of the image development frame body of the vicinity of the antenna member of 1st Embodiment. 6 is a cross-sectional view of a developing device frame in the vicinity of an antenna member in Comparative Examples 1 and 2. FIG. It is a schematic sectional drawing of the image development apparatus of Example 2 according to 1st Embodiment. It is a schematic sectional drawing of the image development apparatus which shows collectively the schematic structure of the detection apparatus of 2nd Embodiment. FIG. 10 is a graph illustrating a relationship between a remaining toner amount and electrostatic capacity according to the second embodiment. FIG. 10 is a graph showing the relationship between the remaining toner amount and electrostatic capacity in Example 3 and Comparative Example 3 according to the second embodiment. It is the schematic diagram explaining an example of the conductive resin sheet. FIG. 3 is a schematic diagram of a toner remaining amount detection circuit. It is explanatory drawing of the measuring method of the top view of an example of an antenna member, and resistance. It is a perspective view for demonstrating arrangement | positioning in the developing device frame of an antenna member. It is a schematic sectional drawing of the image development apparatus of 3rd Embodiment. FIG. 6 is a flowchart of processing for detecting and notifying a remaining toner amount. It is a schematic sectional drawing of the metal mold | die for demonstrating the manufacturing process of the developer container of 3rd Embodiment. FIG. 10 is a graph illustrating an example of a relationship between a remaining toner amount and electrostatic capacity according to a third embodiment. FIG. 5 is a schematic diagram for explaining how toner is accumulated in a developer container. FIG. 10 is a schematic cross-sectional view of a main part of a developing device according to a third embodiment and a graph for explaining the relationship between the transition of the electrostatic detection result and the position of the antenna member. It is a schematic sectional drawing of the principal part of the developing device of the comparative example 5, and the graph for demonstrating the relationship between the transition of the detection result of an electrostatic capacitance, and the position of an antenna member. FIG. 10 is a schematic cross-sectional view of a main part of a developing device according to a fourth embodiment and a graph for explaining the relationship between the transition of a detection result of capacitance and the position of an antenna member. FIG. 7 is a schematic cross-sectional view of a main part of a developing device according to a fifth embodiment, a graph showing an example of the relationship between the remaining amount of toner and capacitance, and the relationship between the transition of the detection result of capacitance and the position of the antenna member. It is a graph for demonstrating. It is a schematic sectional drawing of the principal part of the developing device of the comparative example 6, and the graph for demonstrating the relationship between the transition of the detection result of an electrostatic capacitance, and the position of an antenna member.

Hereinafter, a method for manufacturing a developing device frame , a developer container, a developing device, a process cartridge, and an image forming apparatus according to the present invention will be described in more detail with reference to the drawings.

[First Embodiment]
1. FIG. 1 is a schematic sectional view of an image forming apparatus according to a first embodiment of the present invention. The image forming apparatus 100 of this embodiment is a laser beam printer that forms an image using an electrophotographic method. The image forming apparatus 100 employs a cartridge system, and the process cartridge 120 is detachable from the apparatus main body 110.

  The image forming apparatus 100 is connected to an external host device such as a personal computer or an image reading device, receives image information from the host device, and forms an image corresponding to the image information on a recording material (recording medium, transfer material). And output (print). A sheet material such as paper is preferably used as the recording material.

  The image forming apparatus 100 includes a photosensitive drum 1 that is a drum-type (cylindrical) electrophotographic photosensitive member (photosensitive member) as an image carrier. Around the photosensitive drum 1, the following units are arranged in order along the rotation direction. First, a charging roller 2 which is a roller-shaped charging member as a charging unit is disposed. Next, an exposure device (laser scanner unit) 3 as an exposure unit is arranged. Next, a developing device 4 as a developing unit is arranged. Next, a transfer roller 5 which is a roller-like transfer member as a transfer unit is disposed. Next, a cleaning device 6 as a cleaning means is arranged.

  When a print start signal is input to the image forming apparatus 100 and image formation is started, the photosensitive drum 1 receives a rotational driving force from a driving motor (not shown) as a driving means provided in the apparatus main body 110. Is done. As a result, the photosensitive drum 1 is rotationally driven in the direction of the arrow X1 in the drawing at a predetermined peripheral speed (process speed) (for example, 147.6 mm / s). In this embodiment, the photosensitive drum 1 has an aluminum drum base and an OPC photosensitive layer provided on the drum base. The charging roller 2 is disposed in contact with the photosensitive drum 1 and rotates following the rotation of the photosensitive drum 1. The surface (outer peripheral surface) of the rotating photosensitive drum 1 is substantially uniformly charged to a predetermined potential having a predetermined polarity (negative polarity in the present embodiment) by the charging roller 2. At this time, a predetermined charging bias (charging voltage) is applied to the charging roller 2 from a charging power supply (high voltage power supply) (not shown) provided in the apparatus main body 110. In the present embodiment, as the charging bias, an AC voltage Vpp = 1.6 kV (frequency 1600 Hz) at which the charging roller 2 is sufficiently discharged and a DC voltage Vdc = −560 V corresponding to the dark portion potential Vd on the photosensitive drum 1 are obtained. The superimposed vibration voltage is applied. The AC component of the charging bias is subjected to constant current control so that a substantially constant current flows between the photosensitive drum 1 and the charging roller 2.

  The surface of the charged photosensitive drum 1 is exposed with a laser beam L corresponding to image information from the exposure device 3. The exposure apparatus 3 outputs from the laser output unit 3a laser light (exposure beam) L modulated in accordance with the time-series electric digital image signal of the image information input from the personal computer 20 or the like to the video controller 19. The laser beam L output from the exposure device 3 enters the process cartridge 120 and is irradiated onto the surface of the photosensitive drum 1. The surface of the photosensitive drum 1 that is substantially uniformly charged is scanned and exposed by the laser beam L, whereby an electrostatic latent image (electrostatic image) corresponding to image information is formed on the surface of the photosensitive drum 1. In this embodiment, the bright portion potential Vl on the photosensitive drum 1 irradiated with the laser beam L is −130V. In the present embodiment, the image portion of the electrostatic latent image is exposed (image exposure method).

  The electrostatic latent image formed on the surface of the photosensitive drum 1 is developed by the developing device 4 with the toner T as a developer. Details of the developing device 4 will be described later.

  On the other hand, at a predetermined control timing, a pickup roller 8 as a conveying unit is driven, and recording materials P such as recording sheets stacked and stored in a recording material tray 7 as a recording material storage unit are separated one by one. Are sent. As a result, the recording material P is conveyed to the transfer portion N at a predetermined control timing by a conveying means (not shown). The transfer roller 5 is in contact with the surface of the photosensitive drum 1 with a predetermined pressing force to form a transfer portion (transfer nip) N. The recording material P is conveyed to the transfer portion N via a transfer guide 9 as a guide member. Then, the toner image on the surface of the photosensitive drum 1 is electrostatically applied to the surface of the recording material P in the process of passing through the transfer portion N as the recording material P is nipped and conveyed between the photosensitive drum 1 and the transfer roller 5. Is transferred to. At this time, the transfer roller 5 is transferred from a transfer power supply (high voltage power supply) (not shown) provided in the apparatus main body 110 to a DC voltage having a polarity opposite to the charging polarity (negative polarity in this embodiment) of the toner at the time of development. A bias (transfer voltage) is applied.

  The recording material P onto which the toner image has been transferred is separated from the photosensitive drum 1 and conveyed to a fixing device 10 as a fixing unit provided on the downstream side in the conveying direction of the recording material P in the transfer portion N. The recording material P is heated and pressurized in the fixing device 10 and undergoes a toner image fixing process. In the present embodiment, the fixing device 10 includes a heating roller having a halogen heater therein, and a pressure roller that is pressed against the heating roller. The fixing device 10 heats and pressurizes the toner image transferred to the surface of the recording material P while sandwiching and transporting the recording material P in the fixing nip between the fixing roller and the pressure roller. As a result, the toner image is melted and fixed on the surface of the recording material P. Thereafter, the recording material P is discharged to a discharge tray 11 provided in the upper part of the apparatus main body 110 in the drawing.

  The surface of the photosensitive drum 1 after the recording material P is separated is cleaned by the cleaning device 6 and is repeatedly used in the image forming process starting from the above-described charging. The cleaning device 6 removes deposits such as transfer residual toner from the surface of the rotating photosensitive drum 1 by a cleaning blade 61 serving as a cleaning member disposed in contact with the photosensitive drum 1, and collects it in a recovery toner container 62. To do.

2. Process Cartridge FIG. 2 is a schematic sectional view of the process cartridge 120. In the present embodiment, the photosensitive drum 1, the charging roller 2 as the process means acting on the photosensitive drum 1, the developing device 4, and the cleaning device 6 are integrally formed into a cartridge, and a process cartridge that is detachable from the apparatus main body 110. 120 is configured.

  The process cartridge 120 is configured by connecting a cleaning unit 12 and a developing unit (developing device) 4 separate from the cleaning unit 12.

  The cleaning unit 12 includes a photosensitive drum 1, a charging roller 2, and a cleaning device 6. The cleaning unit 12 includes a cleaning frame body 60 that forms a collected toner container 62 and supports the photosensitive drum 1, the charging roller 2, and the cleaning blade 61. Details of the developing unit 4 will be described later.

  In general, a process cartridge is a cartridge in which an image carrier such as a photoconductor and process means acting on the image carrier are integrated into a cartridge and can be attached to and detached from the main body of the image forming apparatus. is there. Examples of the process means include a charging means, a developing means, a cleaning means, and a toner charging means for charging the transfer residual toner. Here, it is assumed that the process cartridge is a cartridge in which at least the developer container or the developing device and the image carrier are integrally formed and can be attached to and detached from the apparatus main body of the image forming apparatus.

3. Developing Device FIG. 3 is a schematic cross-sectional view of the developing device 4 in the present embodiment. In the figure, functional blocks constituting a detection device 130 described later are also schematically shown.

  The developing device 4 of the present embodiment forms a developer container 46 that stores a magnetic one-component developer (toner) T as a developer, and has a developing frame 40 for supporting each element described later. The developer container 46 includes a developing chamber 46a and a toner chamber 46b. In the present embodiment, the developer accommodating portion 40a is configured by the developing chamber 46a and the toner chamber 46b, which are formed by the developing frame 40 and can accommodate the toner T.

  The developing chamber 46a is a cylindrical member made of a non-magnetic material as a developer carrier so that a part of the opening 46c formed on the photosensitive drum 1 side is exposed to the outside of the developing chamber 46a. A certain developing sleeve 41 is arranged. Both ends of the developing sleeve 41 in the longitudinal direction (rotational axis direction) are rotatably supported by the developing frame 40. The developing sleeve 41 is disposed to face the photosensitive drum 1 with a predetermined interval. The developing sleeve 41 is driven to rotate in the direction indicated by an arrow X2 in the drawing when a rotational driving force from a driving motor (not shown) provided in the apparatus main body 110 is transmitted. In the hollow portion of the developing sleeve 41, a magnet roller 44 having a plurality of magnetic poles in the circumferential direction as a magnetic field generating means is disposed. The magnet roller 44 is fixedly supported (non-rotatable) by the developing device frame 40. Further, a developing blade 42 that is a restricting member formed of an elastic member as a developer layer thickness restricting unit is disposed in the developing chamber 46 a so as to contact the outer peripheral surface of the developing sleeve 41. The developing blade 42 is supported by the developing frame 40.

  On the other hand, a stirring member 45 as a developer stirring means is disposed in the toner chamber 46b. The stirring member 45 includes a stirring shaft 45a and a stirring sheet member 45b fixed to the stirring shaft 45a. The stirring shaft 45a is rotatably supported by the developing device frame 40. The agitating member 45 is driven to rotate in the direction of arrow X3 in the figure by receiving a rotational driving force from a drive motor (not shown) provided in the apparatus main body 110. The toner T accommodated in the toner chamber 46b is removed from the toner chamber 46b through the toner supply port 46d which is an opening for communicating between the developing chamber 46a and the toner chamber 46b when the stirring member 45 is driven to rotate. It is conveyed to the developing chamber 46a.

  The toner supply port 46d is sealed with a seal member 48 (see FIG. 16) in order to prevent toner leakage during transportation of the process cartridge 120. Until the start of the use of the process cartridge 120, the seal member 48 is present to prevent toner leakage. The seal member 48 may be removed manually, or an opening member is provided in the toner chamber 46b or the developing chamber 46a, and the seal member 48 is automatically removed by a method such as rotating and winding by applying a drive to the opening member. It may be configured. Further, the opening member may be used as the stirring member 45. For example, when the stirring member 45 has the stirring shaft 45a and the stirring sheet member 45b, the stirring sheet member 45b and the seal member 48 may be used together, and the stirring shaft 45a may have a function of an opening member. The seal member 48 may be attached to the stirring shaft 45a separately from the stirring sheet member 45b (FIG. 16). In relation to the electrode for detecting the developer amount, when the seal member 48 rotates and stirs while holding the developer, a constant capacitance is detected between the electrodes even though there is no developer that can be used for image formation. Will be. In order to prevent this, a configuration may be adopted in which a hole is provided in a portion other than the toner sealing portion of the seal member 48 so that the developer caught in the seal member 48 falls on the bottom surface of the developer container 46. Until the seal member 48 is removed, the toner T is stored only in the toner chamber 46b of the developing chamber 46a and the toner chamber 46b (FIG. 3).

  In addition, an antenna member 43 constituting a detection device 130 described later is disposed on a part of the bottom surface of the toner chamber 46b.

  The toner T conveyed to the developing chamber 46 a is attracted to the developing roller 41 by the magnetic force of the magnet roller 44 contained in the developing sleeve 41, and the developing blade 42 and the developing sleeve 41 come into contact with the rotation of the developing roller 41. It is conveyed toward the part (FIG. 3). Then, the toner T passes through a contact portion between the developing blade 42 and the developing sleeve 41, thereby being given a charged charge (tribo) due to friction and being restricted in its layer thickness. Thereafter, the toner T is conveyed toward the developing region 31 where the photosensitive drum 1 and the developing sleeve 41 face each other.

  A predetermined developing bias (developing voltage) is applied to the developing sleeve 41 from a developing power source (high voltage power source) as voltage applying means provided in the apparatus main body 110. In this embodiment, an oscillating voltage in which a DC voltage (for example, Vdc = −400 V) and an AC voltage (for example, peak-to-peak voltage = 1500 Vpp, frequency f = 2400 Hz) are superimposed is applied as the developing bias. The photosensitive drum 1 is electrically grounded. As a result, an electric field is generated in the developing region 31 where the photosensitive drum 1 and the developing sleeve 41 face each other. The charged toner T conveyed to the developing area 31 is transferred to the surface of the photosensitive drum 1 according to the electrostatic latent image on the surface of the photosensitive drum 1 by the action of this electric field. As a result, the electrostatic latent image on the photosensitive drum 1 is developed with the toner T. In the present embodiment, the same polarity as the charged polarity of the photosensitive drum 1 (negative polarity) is applied to the exposed portion (image portion) on the photosensitive drum 1 where the absolute value of the potential is attenuated by exposure after being uniformly charged. The electrostatic latent image is developed by attaching the charged toner T to the toner (reversal development method).

  In this embodiment, an example in which a magnetic one-component developer (toner) is negatively charged to develop the toner into an electrostatic latent image has been described. However, a non-magnetic developer or a two-component developer is used. May be. Further, development may be carried out by charging to positive polarity instead of negative polarity.

4). Detection Device Next, a capacitance detection type detection device (developer amount detection device) 130 as detection means (developer amount detection means) for detecting the amount of developer in the present embodiment will be described.

  The detection device 130 according to this embodiment includes a developing sleeve 41 as a first electrode, an antenna member 43 as a second electrode, a developing power supply 131, a capacitance detection circuit 132, a controller unit 133, and the like. The antenna member 43 is disposed on the surface of the developing frame 40 and has a surface facing the developing sleeve 41. In the present embodiment, the antenna member is formed on the flat portion from the viewpoint of ease of manufacture. Then, based on the electrostatic capacitance between the developing sleeve 41 and the antenna member 43, the amount of toner T in the housing portion is detected. The electrostatic capacity detection circuit 132 and the controller unit 133 constitute a developer remaining amount detection device (toner remaining amount detection device) 134. This will be described in more detail below.

  In the present embodiment, the developing sleeve 41 also functions as a first electrode (input-side electrode) for detecting capacitance. An antenna member 43 serving as a capacitance detection member is provided as a second electrode (output-side electrode, counter electrode) for detecting the capacitance. In the present embodiment, the antenna member 43 is composed of a conductive resin sheet that is a conductive resin member. The antenna member 43 has a predetermined length in each of a longitudinal direction substantially parallel to the longitudinal direction (rotation axis direction) of the developing sleeve 41 and a short direction intersecting the longitudinal direction (substantially orthogonal in the present embodiment). It has the part of the planar view rectangle (rectangle) which has. In the present embodiment, the rectangular portion serves as a measurement unit that forms a surface facing the developing sleeve 41. The antenna member 43 may have a portion for forming a conductive path in addition to a measurement portion that forms a surface facing the developing sleeve 41. For example, a portion for forming a conductive path may be continuously formed as one sheet at an end portion in the longitudinal direction of the rectangular measurement unit. As will be described in detail later, this conductive resin sheet is a sheet-like member having a conductive single-layer structure or a multi-layer structure formed on the basis of a resin. The antenna member 43 is disposed on a part of the bottom surface of the toner chamber 46 b formed by the developing frame body 40, and the amount of the toner T existing between the surface facing the developing sleeve 41 and the developing sleeve 41. Changes can be detected. In the present embodiment, the antenna member 43 is planar (flat).

  When an AC voltage (AC bias) is applied to the developing sleeve 41, a current corresponding to the electrostatic capacity between the developing sleeve 41 and the antenna member 43 is induced. This electrostatic capacity changes according to the amount of toner T between the developing sleeve 41 and the antenna member 43. That is, since the relative permittivity of the toner T is larger than the relative permittivity of air, the detected capacitance increases as the amount of the toner T existing between the electrodes increases. The value of the current flowing through the antenna member 43 is determined by the electrostatic capacitance provided in the apparatus main body 110 via the contact (not shown) provided in the process cartridge 120 and the contact (not shown) provided in the apparatus main body 110. It is measured by the capacitance detection circuit 132. In the present embodiment, the capacitance detection circuit 132 generates a voltage signal corresponding to the current value (that is, the capacitance value) and inputs the voltage signal to the controller unit 133 provided in the apparatus main body 110. The controller unit 133 can obtain the amount of toner T from the input voltage signal based on information (data table or the like) indicating a relationship between a preset capacitance and the amount of toner T.

  Further, the controller unit 133 determines the toner T to the user or the like based on the obtained amount of the toner T, via a display unit of the apparatus main body 110 serving as a notification unit or a display on a monitor of a personal computer connected to the apparatus main body 110. Information related to the amount of This can prompt the user or the like to prepare a new process cartridge 120.

  FIG. 4 is a graph showing the relationship between the amount of toner T in the container 40a and the capacitance in the present embodiment. In the present embodiment, the antenna member 43 is provided on the bottom surface of the toner chamber 46b, and a change in the amount of toner T between the developing sleeve 41 and the antenna member 43 is detected. In the present embodiment, a change in the amount of toner T from when the toner T is consumed to some extent and the amount of toner T in the container 40a reaches about 150 g until the toner runs out is detected. Thereby, in the present embodiment, the amount of toner T (remaining amount) during that time can be sequentially notified to the user or the like. However, since the range of the remaining amount of toner T that can be detected varies depending on the arrangement of the antenna member 43, the antenna member 43 can be arranged at an arbitrary position as desired. The antenna member 43 may be disposed in the toner chamber 46b or the developing chamber 46a.

  In the present embodiment, the length in the longitudinal direction of the antenna member 43 is set to a length that covers substantially the same range as the image area (a direction substantially orthogonal to the image conveyance direction). This is because even if the amount of toner T is uneven in the longitudinal direction, detection accuracy can be improved by detecting a wide range of capacitance including the unevenness. Therefore, the length in the longitudinal direction of the antenna member 43 may be a length over a wider range than the image area. However, if desired, for example, the antenna member 43 having a shorter length in the longitudinal direction may be disposed near the center or the end of the image area. For example, if allowed from the viewpoint of detection accuracy, if the unevenness in the amount of toner T in the longitudinal direction does not occur due to the stirring member 45 or the like, the unevenness in the amount of toner T in the longitudinal direction (or the image damage caused by it) itself can be reduced. There are cases where it is detected by a capacitance detection method. Further, by providing a plurality of conductive resin members having different lengths in the longitudinal direction of the developing sleeve 41, differences in the electrostatic capacity between the developing sleeve 41 and the conductive resin member and a plurality of electrostatic capacitances are detected, and the deviation of the toner and the toner amount are detected. It may be configured to detect. Even if it is not a plurality of conductive resin members with different lengths, the difference in capacitance is detected using a configuration in which the length (width) in the short direction is gradually shortened from one end to the other in the long direction. May be.

  Further, the length of the antenna member 44 in the short direction may be longer or shorter than that of the present embodiment. For example, when it is desired to detect the remaining amount of toner T in a wider range, the antenna member 43 The length in the short direction can be made longer than that in the present embodiment. In that case, it is not limited to the bottom surface of the toner chamber 46b, but may extend to any range of the surface of the developing device frame 40. Further, for example, when it is desired to accurately detect the remaining amount of toner T in a specific range such as immediately before the toner runs out, the length of the antenna member 43 in the short direction is made shorter than that in the present embodiment, and development is performed. It can be brought closer to the sleeve 41.

  In this embodiment, since an AC voltage is applied to the developing sleeve 41 during image formation, the developing sleeve 41 is used as an AC voltage input unit (an electrode on the input side) for detecting the amount of toner T, and an output unit ( An antenna member 43 is provided as an output side electrode). Therefore, in the present embodiment, the developing device frame 40 has a holding portion for holding the developing sleeve 41. However, the AC voltage input unit is not limited to the developing sleeve 41, and may be any member having conductivity. In that case, the developing device frame 40 only needs to have a holding portion for holding the conductive member. Moreover, the electrode comprised with a conductive resin sheet may be an input part (input-side electrode) of an alternating voltage. In this case, an AC voltage may be applied from the AC voltage source to the electrode formed of the conductive resin sheet via the contact provided on the process cartridge 120 and the contact provided on the apparatus main body 110.

  In the present embodiment, a detection device that detects a capacitance between the developing sleeve 41 and the electrode is described. However, the present invention is not limited to this, and both of the pair of electrodes may be conductive resin members. That is, it is also possible to detect the developer amount using the difference in capacitance between the conductive resin members (FIG. 13). In this case, the detection device can also be used to detect the remaining amount of non-magnetic toner used in a full-color image forming apparatus in which a plurality of cartridges can be attached and detached.

5). Manufacturing Method Next, a manufacturing method of the developer container 46 in the present embodiment will be described.

  As described above, conventionally, as a method of manufacturing a developer container in which the amount of developer is detected by the capacitance detection method, the antenna member is adhered to the frame with double-sided tape, or vapor deposition or printing is performed on the frame. There is a way to. However, in such a method, the manufacturing process is likely to be complicated due to the necessity of a step for post-processing the frame after the frame is formed. In addition, for example, in the method of adhering to the frame with double-sided tape, the detection accuracy may be reduced due to variations in the dimensions and positions of the components.

  On the other hand, for example, a method of inserting a plate-like member (SUS sheet metal or the like) made of metal when molding a resin frame into an antenna member is conceivable. However, in this method, since the degree of shrinkage of the resin when the resin used for molding is cooled is large and the shrinkage of the metal plate-like member is small, the container is likely to be distorted and is difficult to design. Moreover, it is necessary to provide the site | part (fixed part, fixed shape) which fixes an antenna member and a frame. For example, it is necessary to prevent the antenna member from moving by forming the end surface and both surfaces of the antenna member at the end portion in the longitudinal direction of the antenna member so as to be covered with the fixing portion of the frame body. Therefore, it is necessary to make the frame itself thicker, and the frame body tends to have a complicated uneven shape at a portion where the mold and the frame are fixed, and the frame body tends to be large. In addition, in this method, the fixing portion, which has an uneven shape for fixing the antenna member, does not change in capacitance in a region where the change in capacitance originally occurs due to a change in the amount of developer. Since it becomes an area | region, the performance of a plate-shaped member is not fully utilized.

  In this regard, the use of a resin electrode (conductive part) as an electrode for detecting capacitance is because it is easy to form with high accuracy by a relatively simple method using a mold, etc. This is also advantageous in terms of simplifying the manufacturing process and improving detection accuracy. In addition, as will be described later, using a resin electrode can reduce the cost of the electrode itself, and also can suppress a decrease in detection accuracy due to adhesion of the developer to the electrode when a magnetic developer is used. It is advantageous.

  For example, it is conceivable to form the conductive portion in the frame with a conductive resin in two colors. However, since this method requires two molding steps, there are still points to be improved in order to manufacture more easily. Further, as described above, in the method of providing the electrode layer on the sheet member for preventing the scattering of the developer, the manufacturing process tends to be complicated due to the process of attaching the sheet member to the frame of the developing device.

  Thus, it is desired to easily manufacture a developer container in which the amount of developer is detected by a capacitance detection method. There is also a demand for a manufacturing method that makes it possible to detect the amount of developer with high accuracy.

  Therefore, in the present embodiment, when the developing frame 40 is molded, the conductive resin sheet constituting the antenna member 43 is first held in the mold, and then the resin (synthetic resin) forming the developing frame 40 is used as the mold. Inject. Thereby, the developing device frame 40 to which the antenna member 43 is integrally fixed is formed. This will be described in more detail below.

  In the present embodiment, as the conductive resin sheet 24, a sheet made of PS (polystyrene) resin sheet coated with carbon as a conductive material is used. Here, the surface of the conductive resin sheet 24 coated with carbon is defined as A surface (FIG. 6). Further, the surface of the conductive resin sheet 24 opposite to the A surface and having the PS resin exposed is defined as a B surface. In the present embodiment, the A surface of the conductive resin sheet 24 is a surface that comes into contact with the mold when the developing frame 40 is formed. Thus, at least a part (substantially all in this embodiment) of the surface of the conductive resin sheet 24 that contacts the mold is the surface of the antenna member 43 that faces the developing sleeve 41. In the present embodiment, at least the B surface of the conductive resin sheet 24 is a surface that comes into contact with the resin injected into the mold when the developing frame 40 is formed. In the present embodiment, the PS resin is also exposed on the side end surface between the A surface and the B surface, and this side end surface is also a surface that contacts the resin injected into the mold when the developing frame 40 is formed. is there.

  FIG. 5 schematically shows a manufacturing process of the developing device frame 40 in the present embodiment. The developing frame 40 may be configured by combining a plurality of molded frame portions. In the present embodiment, the developing frame 40 includes a lower frame 40A that forms the bottom surface of the accommodating portion 40a as shown in FIG. 3, and an upper frame 40B that covers the lower frame 40A like a lid. And are configured. And these lower side frame 40A and upper side frame 40B are shape | molded separately. In this embodiment, since the antenna member 43 is disposed on the lower frame body 40A, FIG. 5 schematically shows a manufacturing process of the lower frame body (hereinafter, the lower frame body 40A is simply referred to as “development”. Sometimes referred to as “frame 40”).

  As shown in FIG. 5A, the mold 201 of the injection molding machine 200 includes a first mold 202 (or male mold (core)) and a second mold 203 (or female mold (cavity)). Have. The first mold 202 has a surface 221 that forms a surface on the housing portion side of the developing device frame 40. On the other hand, the second mold 203 has a surface 231 that forms a surface (outer side) opposite to the housing portion 40 a of the developing frame 41. The first mold 202 is provided with fine air holes (air suction portions) 222 in a predetermined holding region Y for holding the conductive resin sheet 24. A suction device 204 is connected to the minute air hole 222, and the suction device 204 can suck air in the direction of arrow S1 in the figure. The second mold 203 is provided with a gate 232.

  When forming the developing device frame 40 using the injection molding machine 200, first, as shown in FIG. 5B, the surface A of the conductive resin sheet 24 is brought into contact with the surface 221 of the first mold 202. The air suction by the suction device 204 is activated. Thereby, the A surface of the conductive resin sheet 24 is adsorbed and held on the surface 221 of the first mold 202.

  After that, as shown in FIG. 5C, the first mold 202 and the second mold 203 are brought into close contact with each other with a desired pressure to form a cavity for forming the developing frame 40, and the developing frame 40 is formed. Is injected from the gate 232 in the direction of the arrow S2. Then, the injected thermoplastic resin is cooled and cured (solidified) to form the developing frame 40 to which the antenna member 43 made of a conductive resin sheet is integrally fixed. At this time, in this embodiment, as a thermoplastic resin to be injected into the mold 201, an HIPS (impact polystyrene) resin having compatibility with at least the B surface (further side end surface in the present embodiment) of the conductive resin sheet 24 is used. Use. As a result, the antenna member 43 formed of a conductive resin sheet is formed integrally with the developing frame 40 by injecting the resin into the mold 201 and curing the resin.

  Thereafter, as shown in FIG. 5D, the developing device frame 40 to which the antenna member 43 is integrally fixed can be removed from the mold 201 in a state where air suction by the suction device 204 is stopped.

The lower frame body 40A molded as described above and the separately molded upper frame body 40B are joined together by an appropriate fixing method such as heat welding. Thereby, the developer container 46 formed by the developing device frame 40 can be manufactured. Further, prior to coupling the upper frame member 40 B and the lower frame member 40 A and / or after, to the developer container 46, mounting the elements of the above-mentioned developing apparatus 4 (held to include a developer sleeve 41 Thus, the developing device (developing unit) 4 can be manufactured. Further, the process cartridge 120 can be manufactured by connecting (holding) the cleaning unit 12 to the developing device (developing unit) 4.

  In the present embodiment, the metal contact is pressed against the conductive portion (not shown) at the end of the developing device frame 40 in which the antenna member 43 is integrally formed. Then, a conductive member having one end connected to or continuous with the contact is wound around the outside of the process cartridge 120, and the other end is used as a contact with the apparatus main body 110. As described above, the current flowing through the antenna member 43 when an AC voltage is applied to the developing sleeve 41 during image formation is detected by the capacitance detection circuit 132 provided in the apparatus main body 110.

6). Effect According to the present embodiment, when forming the developing device frame 40, the conductive resin sheet 24 is adsorbed and held in advance on the mold 201 (first mold 202), and with less man-hours, The developing device frame 40 in which the antenna member 43 is integrally formed can be manufactured.

  FIG. 6A is a cross-sectional view of the developing device frame 40 in the vicinity of the antenna member 43 at the center in the longitudinal direction of the antenna member 43 (cross section along the short side direction of the antenna member 43). As described above, in the present embodiment, at least the B surface (the side end surface in the present embodiment) of the conductive resin sheet 24 and the thermoplastic resin injected into the mold 201 are compatible. Therefore, at least the B surface (further side end surface in the present embodiment) of the conductive resin sheet 24 is integrated with the thermoplastic resin injected into the mold when the developing frame 40 is formed. Therefore, the formed developing device frame 40 is already integrated with the antenna member 43, and it is not particularly necessary to have a special shape for fixing the antenna member 43.

  Further, it is known that the capacitance changes in proportion to the reciprocal of the distance between two electrodes. In this regard, according to the present embodiment, molding is performed by holding the surface A of the conductive resin sheet 24 that faces the developing sleeve 41 so as to be in contact with the surface of the mold 201 (first mold 202). Is going. Therefore, for example, variations in the position of the A surface due to variations in the thickness of the conductive resin sheet 24 and the fixing method of the conductive resin sheet 24 do not substantially occur. Therefore, by suppressing the variation in the distance between the two electrodes, it is possible to suppress the variation in the capacitance and to detect the amount of the toner T with high accuracy.

  Further, according to the present embodiment, the entire B surface of the conductive resin sheet 24 is fixed to the developing frame 40 substantially uniformly and integrally. Therefore, for example, the antenna member 43 is partially peeled off due to deformation of the developer container 46 when an external force is temporarily applied, and the detection accuracy of the amount of toner T is unlikely to decrease.

  In the present embodiment, as a method of holding the conductive resin sheet 24 in the mold 201, a method of adsorbing by air suction is used. However, the present invention is not limited to this, and it is sufficient that the conductive resin sheet 24 can be held at a desired position of the mold 201 by using, for example, electrostatic force, magnetic force, gravity, or any other binding force. For example, it may be held by grease. However, holding by air suction is preferable because it can be easily performed without using a special material. Further, in this embodiment, substantially the entire surface of the conductive resin sheet 24 is sucked by air. However, by providing the air hole 222 at least on the gate 232 side of the conductive resin sheet 24, the conductivity at the time of injecting the resin into the mold 201 is achieved. It becomes easy to suppress misalignment of the resin sheet 24 and the like.

  In the present embodiment, the conductive resin sheet 24 is a material having compatibility with the thermoplastic resin injected into the mold 201 when the developing frame 40 is molded at least on the developing frame 40 side (frame side). (In this embodiment, the B surface and the side end surface). Here, the term “compatible” generally refers to a property in which two or more kinds of substances have an affinity for each other and form a solution or admixture by mixing substantially uniformly without causing a chemical reaction. Here, under the conditions (temperature, time, etc.) that are reasonable as a method for forming the developing frame described above, the developing frame is caused by dissolution or mixing at least part of the interface with the resin injected into the mold. The property that can be fixed to the body shall be said. Even if it is the same material as the resin injected into the mold, or it is a different material, it can be said that it is a compatible material if it has the above-mentioned properties. However, the present invention is not limited to this, and the conductive resin sheet 24 has an adhesive property to the resin injected into the mold 201 when the developing frame 40 is molded at least on the developing frame 40 side. You may have the surface comprised with the material which has. Here, adhesiveness generally refers to the property of bonding two surfaces by chemical or physical force or both. Here, under the conditions (temperature, time, etc.) that are reasonable as a method for forming the developing frame described above, an action different from the case of the compatible material at the interface with the resin injected into the mold. The property that can be fixed to the developing frame by the above. Here, since it is sufficient that the resin to be injected has compatibility or adhesiveness, it is strictly discriminated by which property the conductive resin sheet is fixed to the developing frame. There is no need.

  For example, when the resin injected into the mold is a HIPS resin, the material having compatibility therewith is a PS resin, a HIPS resin, or a carbon-dispersed PS resin in which, for example, carbon black is dispersed as a conductive material. Examples thereof include dispersed HIPS resin. For example, when the resin injected into the mold is HIPS resin, the material having adhesiveness even if not compatible with this is EVA (ethylene vinyl acetate), or a conductive material for this, for example Examples thereof include carbon-dispersed EVA in which carbon black is dispersed.

  Further, the surfaces having compatibility or adhesiveness with the resin injected into the mold of the conductive resin sheet 24 are all surfaces on the developing frame body 40 side (in this embodiment, substantially the entire surface of the B surface and the substantially entire surface of the side end surface). ) Is not limited thereto. If the antenna member 43 is sufficiently fixed to the developing frame 40, a part of the surface of the conductive resin sheet 24 on the developing frame 40 side may not have both compatibility and adhesiveness. However, from the viewpoint of better suppressing the peeling of the antenna member 43 from the developing device frame 40, the B surface opposite to the A surface (the surface facing the other electrode) of the conductive resin sheet 24 is It is preferably compatible or adhesive with the resin injected into the mold. In this case, a part of the B surface may have the compatibility or adhesiveness, but it is more preferable that substantially the entire surface of the B surface has the compatibility or adhesiveness.

  Moreover, as for the conductive resin sheet 24, either A surface, B surface, or these both surfaces may have electroconductivity. When the conductive resin sheet 24 is provided as an antenna member on the developing frame 40, is the conductive portion of the antenna member electrically connected to the capacitance detection circuit 132 (in the case of an electrode on the output side)? Or any structure that can be conducted (in the case of an electrode on the input side). And the conductive resin sheet 24 should just have sufficient electroconductivity as an electrode for the detection of the quantity of the developer by an electrostatic capacitance detection system, when it is provided in the developing device frame 40 as an antenna member. . Therefore, in this embodiment, the conductive resin sheet 24 has a two-layer structure having a conductive layer, but may have a structure of three or more layers having at least one conductive layer. The conductive resin sheet 24 is not limited to a sheet-like member having a multi-layer structure formed on the basis of a synthetic resin, and is a single-layer sheet-like member having conductivity formed on the basis of a synthetic resin. It may be. For example, as the conductive resin sheet member 43, a conductive sheet-like member formed of a resin in which carbon black as a conductive material is dispersed can be used. In this case, the resin (base) serving as the basis of the conductive resin sheet member 43 is a resin having compatibility or adhesiveness with the resin injected into the mold when the developing frame 40 is molded. Accordingly, at least the developing frame body 40 side (usually the whole) of the conductive resin sheet 24 is compatible or adhesive with the resin injected into the mold when the developing frame body 40 is molded. Can do.

  In the present embodiment, a PS resin sheet-like member having a carbon coat is used as the conductive resin sheet 24 having a multi-layer structure. However, the present invention is not limited to this. For example, it may be a resin sheet-like member coated with a conductive substance other than carbon, or a resin sheet-like member deposited with a conductive substance or printed. Also, for example, a two-layer structure in which a protective layer for preventing abrasion is formed on the surface of a conductive sheet-like member, or a conductive layer in which a PS resin substrate is dispersed in a PS resin and a conductive material such as carbon black A three-layer structure sandwiched between In these cases, as in the present embodiment, the resin sheet member (substrate) is formed of a material that is compatible or adhesive with the resin injected into the mold when the developing frame 40 is molded. (FIG. 12).

  The conductive resin sheet 24 is preferably composed of a non-magnetic or diamagnetic sheet-like member so that toner T, which is a magnetic material, does not adhere when magnetic toner is used.

  Further, the conductive material is not limited to carbon black, and any conductive material such as graphite, carbon fiber, or carbon nanotube may be used.

7). Shrinkage of Conductive Resin Sheet When the developing frame 40 is molded or after demolding, the developing frame 40 contracts. At this time, if the Young's modulus of the conductive resin sheet 24 is larger than the Young's modulus of 3.5 GPa of the HIPS resin forming the developing frame 40, the developing frame 40 may be warped. If the distance between the antenna member 43 made of the conductive resin sheet and the developing sleeve 41 changes beyond the allowable level due to this phenomenon, the detection accuracy of the amount of toner T is lowered. It is possible.

  The phenomenon that the developing frame 40 is warped is that when a conductive resin sheet having a Young's modulus larger than the material forming the developing frame 40 is used, the developing frame 40 is formed when the developing frame 40 is molded or after demolding. It is a phenomenon that occurs due to the shrinkage. That is, when forming the developing frame 40 or after removing the mold, the conductive resin sheet 24 also contracts in accordance with the contraction of the developing frame 40. However, when the Young's modulus of the conductive resin sheet 24 is larger than the Young's modulus of the material of the developing frame 40 and there is a difference in the contraction amount between the developing frame 40 and the conductive resin sheet 24, the conductive resin sheet 24 develops. The contraction of the frame body 40 cannot be absorbed due to deformation or the like. For example, as shown in FIG. 6B, against the contraction of the developing frame 40 in the direction indicated by the arrow A (the direction along the short direction of the conductive resin sheet 24), the arrow B shown in the vicinity of the conductive resin sheet 24 is provided. Shrinkage in the direction (the direction along the short direction of the conductive resin sheet 24) occurs. At this time, since the shrinkage amount in the direction of the arrow B is smaller than the shrinkage in the direction of the arrow A, the developing frame 40 is warped in the direction of the arrow C (the side with the larger shrinkage amount). it is conceivable that. Here, in the conductive resin sheet in which carbon black is dispersed in EVA, when the conductive resin sheet 24 having a Young's modulus of 2.5 GPa to 3.5 GPa is used by changing the dispersion state of the carbon black, the developing frame body 40 is used. However, the phenomenon of warping did not occur. In addition, when the PS resin (Young's modulus = 2.5 GPa) subjected to carbon coating, which is the conductive resin sheet 24 in this embodiment, was used, the developing frame 43 did not warp. Similarly, when a conductive resin sheet with Young's modulus = 3.5 GPa in which carbon is dispersed in PS resin or a conductive resin sheet with Young's modulus = 0.2 GPa in which carbon is dispersed in EVA, a developing frame is used. The phenomenon that 40 was warped did not occur.

  For these reasons, it is preferable to use a conductive resin sheet 24 having a Young's modulus equal to or smaller than that of the resin forming the developing frame 40. That is, the Young's modulus of the conductive resin sheet 24 is preferably equal to or lower than the Young's modulus of the resin forming the developing frame 40. Moreover, since it becomes easier to follow the shrinkage of the developing frame 40, the Young's modulus of the conductive resin sheet 24 is smaller than the Young's modulus of the resin forming the developing frame 40 (for example, 1/10 or less). Is more preferable. For example, when the resin forming the developing frame 40 is a HIPS resin (Young's modulus = 3.5 GPa), for example, a conductive resin sheet (Young's modulus = 0.2 GPa) in which carbon black is dispersed in EVA is preferably used. it can.

8). Comparison between Examples and Comparative Examples Next, the superiority of the present embodiment will be described using comparative examples. In addition, also about a comparative example, the same code | symbol is attached | subjected to the element which has a function and a structure equivalent to the thing of this embodiment.

(Configuration of Example 1)
Example 1 is as described above for the present embodiment.

(Configuration of Comparative Example 1)
FIG. 7A is a cross-sectional view of the developing frame body 40 in the vicinity of the antenna member 47 at the center portion in the longitudinal direction of the antenna member 47 of Comparative Example 1 (cross section along the short direction of the antenna member 47). In Comparative Example 1, an antenna member 47 that is a plate-like member (SUS sheet metal) formed of SUS (stainless steel) is attached to a molded developing frame 40 with a double-sided tape 48. That is, in Comparative Example 1, the method for manufacturing the developer container 46 includes a step of attaching the antenna member 47 prepared in advance to the molded developing frame 40 with the double-sided tape 48.

(Advantage of Example 1 over Comparative Example 1)
In Comparative Example 1, a step of fixing the antenna member 47 to the molded developing frame 40 with the double-sided tape 48 is required. On the other hand, in Example 1, when the developing frame 40 is formed, the developing resin frame 24 in which the antenna member 43 is integrally formed is obtained by simply adsorbing and holding the conductive resin sheet 24 to the mold 201. The body 40 can be obtained. Therefore, in Example 1, compared with Comparative Example 1, the developing frame 40 having the antenna member 43 can be manufactured with fewer steps.

  In Comparative Example 1, the position of the antenna member 47 may vary due to variations in the thickness of the double-sided tape 48 and the antenna member 47. On the other hand, in Example 1, since the A surface of the antenna member (conductive resin sheet) 43 is a surface that is held so as to contact the mold 201, the antenna member 43 substantially varies in thickness due to variations in the thickness of the antenna member 43. There is no variation in the position of the member 43. Therefore, in Example 1, compared to Comparative Example 1, the accuracy of the distance between the antenna member 43 and the developing sleeve 41 is high, and the amount of toner T can be detected with high accuracy.

(Configuration of Comparative Example 2)
FIG. 7B is a cross-sectional view of the developing frame body 40 in the vicinity of the antenna member 47 at the center in the longitudinal direction of the antenna member 47 of Comparative Example 2 (cross section along the short side direction of the antenna member 47). FIG. 7C is a similar view at the end in the longitudinal direction of the antenna member 47 of Comparative Example 2. In Comparative Example 2, when the developing frame 40 is formed, an antenna member 47 that is a SUS sheet metal is inserted.

  In Comparative Example 2, since the double-sided tape 48 is not used for fixing the antenna member 47 as in Comparative Example 1, the antenna member 47 is not bonded to the resin of the developing device frame 40. Therefore, in Comparative Example 2, as shown in FIG. 7B, the antenna member 47 is provided by providing a fixing portion (fixed shape) 49 on the developing frame 40 corresponding to the end portion in the longitudinal direction of the antenna member 47. The developing frame 40 is fixed. In Comparative Example 2, the fixing portion 49 was formed so as to cover the end surface and both surfaces (A surface and B surface) of the antenna member 47 at the end portion in the longitudinal direction of the antenna member 47.

(Advantage of Example 1 over Comparative Example 2)
In Comparative Example 2, the thickness t of the developing device frame 40 at the end in the longitudinal direction of the antenna member 47 is larger than that in Example 1. In Comparative Example 2, a fixing portion 49 formed of resin is provided between the developing sleeve 41 and the antenna member 47. The detection of the amount of toner T using the change in capacitance is realized by changing the capacitance between the electrodes as the toner T is used. In Comparative Example 2, the amount of toner T is reduced as the toner T is used. By providing the fixed portion 49 where the electric capacity does not change, the detection accuracy of the amount of toner T may be lowered. On the other hand, in Example 1, since there is no need to provide a member corresponding to the fixing portion 49, the detection accuracy of the toner T as described above does not decrease.

  In Comparative Example 2, the antenna member 47 may be lifted (partially peeled off) from the developing device frame 40 due to a change in the temperature when the atmosphere is applied or an external force is applied. On the other hand, in Example 1, since the antenna member (conductive resin sheet) 43 is fixed to the developing frame 40 substantially uniformly and integrally on the B surface, the antenna member from the developing frame 40 is fixed. 43 never floats. This is assumed to be because the fixing force between the resins is strong. Thereby, the distance between the developing sleeve 41 and the antenna member 43 is stabilized, and the detection accuracy of the amount of toner T is stabilized. Therefore, the detection accuracy of the amount of toner T is hardly lowered.

(Configuration of Example 2)
This example is configured according to this embodiment, but the shape of the antenna member 43 is different from that of Example 1.

  FIG. 8 is a schematic cross-sectional view of the developing device 4 according to the second embodiment which is a modification of the first embodiment. In the figure, functional blocks constituting the detection device 130 are also schematically shown.

  In this embodiment, as shown in FIG. 8, the surface of the developing frame body 40 on which the antenna member 43 is provided is not a straight shape (flat). However, the conductive resin sheet constituting the antenna member 43 in the present embodiment has flexibility. Therefore, when the developing frame 40 is formed, air suction or the like is performed on the surface of the mold 201 for forming the developing frame 40 having a curved surface as shown in FIG. It is possible to hold it. Further, as described above, even a method other than air suction can be similarly applied to the mold. In addition, the resin sheet which comprises the antenna member 43 in Example 1 may also have flexibility.

  Thus, since the conductive resin sheet which comprises the antenna member 43 has flexibility, the antenna member 43 can be easily arrange | positioned also on the surface of the developing frame 40 made into a curved surface. Accordingly, the remaining amount of the toner amount T in a wider range can be detected by arranging the antenna member 43 in a wider range of the bottom surface of the toner chamber 46a having a curved surface, for example.

(Advantage of Example 2)
Here, for example, a case where an antenna member made of SUS sheet metal is inserted when the developing frame 40 is formed will be considered. It is assumed that the method for fixing the antenna member is the same as that in Comparative Example 2 described above. In this case, since the antenna member is formed of an inflexible SUS sheet metal, the SUS sheet metal is previously processed into a shape corresponding to the curved surface shape of the portion where the antenna member is arranged in the developing frame 40, and then formed into a mold. Set and insert mold. That is, in this case, it is necessary to process the SUS sheet metal into a shape that conforms to the shape of the corresponding portion of the developing frame 40 in advance. In addition, since the curved surface processing of both the mold and the SUS sheet metal has a tolerance, the SUS sheet metal does not adhere to the curved surface of the mold, and a gap may be formed between the mold and the SUS sheet metal. In this case, the accuracy of the distance between the antenna member and the developing sleeve 41 may be reduced.

  On the other hand, in this embodiment, the conductive resin sheet is held on the surface of the curved mold as in the first embodiment without reducing the accuracy of the distance between the antenna member 43 and the developing sleeve 41. The developing frame 40 having the antenna member 43 can be formed simply by making it.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In this embodiment, elements having the same functions or configurations as those in the first embodiment or corresponding to those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the present embodiment, electrical characteristics of the antenna member that are preferable for improving the detection accuracy when the amount of developer is detected by a capacitance detection method using a resin antenna member will be described.

1. Developing Device FIG. 9 is a schematic cross-sectional view of the developing device 4 in the present embodiment. The developing device 4 forms a developer container 46 that accommodates toner T as a developer, and includes a developing frame 40 for supporting each element described later. In the present embodiment, the toner T is a developer having an average particle diameter of 7 μm. In the present embodiment, the developing frame 40 is formed of HIPS (impact resistant polystyrene).

  In the present embodiment, the developing sleeve 41 is formed by coating the surface of an aluminum sleeve, which is a non-magnetic material, with a medium resistance resin layer having a thickness of 10 μm. The volume resistance of this resin layer is about 1 to 10Ω.

  In the hollow portion of the developing sleeve 41, a magnet roller 44 as a magnetic field generating means is disposed. The magnet roller 44 is fixedly supported (non-rotatable) by the developing device frame 40. In this embodiment, the magnet roller 44 has a plurality of magnetic poles (four magnetic poles of S1, N1, S2, and N2 in this embodiment) in which N poles and S poles are alternately arranged in the circumferential direction (see FIG. 20). The magnetic pole S1 is a developing pole that is disposed at a position facing the photosensitive drum 1 and controls the development of the electrostatic latent image by the toner T. The magnetic pole N1 is a regulating pole that is disposed at a position facing a developing blade 42 described later and controls the amount of toner T on the developing sleeve 41. The magnetic pole S <b> 2 is a supply pole (take-in pole) that supplies the toner T in the developer container 46 onto the developing sleeve 41. The magnetic pole N2 is a toner leakage prevention pole (seal pole) disposed at a position where the blowout prevention sheet 32 for preventing leakage of the toner T from the developer container 46 is provided. Since the magnet roller 44 does not rotate and is always held at a fixed position, the magnetic poles are always kept in the same direction.

  In the developing chamber 46a, a developing blade 42 as a regulating member as a developer layer thickness regulating means is disposed so as to abut on the outer peripheral surface of the developing sleeve 41. In the present embodiment, the developing blade 42 is formed by adhering and fixing a urethane rubber blade, which is a plate-like member formed of an elastic member, to a supporting sheet metal, and the supporting sheet metal is the developing frame body 40. It is fixed to. As a result, the urethane rubber blade comes into contact with the developing sleeve 41 with an appropriate contact pressure so that the layer thickness of the toner T on the developing sleeve 41 is appropriately regulated and frictionally charged. In addition, as a regulation member, you may use the thing formed with the magnetic cut or resin. Further, in the developing chamber 46a, a blowout prevention sheet 32, which is a sheet-like member that prevents the blowout of toner, is provided along the edge of the opening 46c opposite to the side where the developing blade 42 is provided. 41 is provided in contact with 41.

  In the present embodiment, an antenna member 43 constituting a detection device 130 described later is disposed on a part of the bottom surface of the developing chamber 46a.

  On the other hand, a stirring member 45 as a developer stirring means is disposed in the toner chamber 46b. The stirring member 45 includes a stirring shaft 45a and a stirring sheet member 45b fixed to the stirring shaft 45a. The stirring shaft 45a is rotatably supported by the developing device frame 40 at both ends in the longitudinal direction (rotation axis direction). The agitating member 45 is driven to rotate in the direction of arrow X3 in the figure by receiving a rotational driving force from a drive motor (not shown) provided in the apparatus main body 110. In the present embodiment, the stirring shaft 45a rotates once in about 1 second. In this embodiment, the stirring sheet member 45b is a PPS sheet (sheet-like member formed of polyphenylene sulfide resin) having a thickness of 100 μm, and one end portion in the short side direction is pressure-bonded or welded to the stirring shaft 45a. Has been fixed. Moreover, in this embodiment, the length of the longitudinal direction of the stirring sheet member 45a is 216 mm. The toner T accommodated in the toner chamber 46b is removed from the toner chamber 46b through the toner supply port 46d which is an opening for communicating between the developing chamber 46a and the toner chamber 46b when the stirring member 45 is driven to rotate. It is conveyed to the developing chamber 46a.

  The toner T conveyed to the developing chamber 46a and sent to the vicinity of the developing sleeve 41 is attracted to the developing roller 41 by the magnetic pole S2 of the magnet roller 44 and supplied to the surface of the developing sleeve 41. The toner T supplied to the developing sleeve 41 by the magnetic force of the magnetic pole S2 is conveyed by the developing sleeve 41 and is regulated by the developing blade 42. At this time, the toner T that has passed through the restricting portion is charged by frictional charging. The electrostatic latent image formed on the photosensitive drum 1 is developed by the toner T that has passed through the restricting portion. On the other hand, the toner T regulated by the developing blade 42 is divided into a toner that is held by the magnetic pole N1 and stays in the vicinity of the developing blade 42, and a toner that is blown to a range where the magnetic force of the magnetic pole N1 does not reach. When the toner T left in the developing container 46 is abundant, the toner T that has been blown off is stirred by the stirring member 45 and then supplied to the developing sleeve 41 again. When the toner remaining in the developing container 46 is small, it falls to the vicinity of the vertically lower portion, that is, the vicinity of the antenna member 43. The dropped toner T is not attached to the antenna member 43, but is pushed out by the toner T sent by the stirring member 45 or attracted to the magnetic force of the magnetic pole S2, thereby being supplied to the developing sleeve 41 again.

  A predetermined developing bias (developing voltage) is applied to the developing sleeve 41 from a developing power source (high voltage power source) as voltage applying means provided in the apparatus main body 110. In this embodiment, an oscillating voltage in which a DC voltage Vdc = −400 V and an AC voltage Vpp = 1400 V (frequency = 2000 Hz, rectangular wave) are superimposed is applied as the developing bias. The photosensitive drum 1 is electrically grounded. As a result, an electric field is generated in the developing region 31 where the photosensitive drum 1 and the developing sleeve 41 face each other.

  The toner supply port 46d is sealed (sealed) by a seal member 48 (FIG. 16) until it is removed at the start of use of the process cartridge 120 in order to prevent toner leakage during transportation of the process cartridge 120. ing. In this embodiment, the seal member 48 is a PS resin sheet, and is adhered in the developer container 46 so that the toner T does not leak from the region in the drawing in order to prevent toner leakage during transportation.

2. Next, the detection device 130 according to the present embodiment will be described. FIG. 9 is a schematic cross-sectional view of the developing device 4 that also shows functional blocks of the detection device 130 of the present embodiment. The basic configuration and operation of the detection device 130 in the present embodiment are substantially the same as those in the first embodiment.

  In the present embodiment, the antenna member 43 as the second electrode (output-side electrode, counter electrode) is disposed on a part of the bottom surface of the developing chamber 46 a formed by the developing frame body 40. The antenna member 43 can detect a change in the amount of toner T existing between the developing sleeve 41 and the surface facing the developing sleeve 41. In the present embodiment, as in the first embodiment, the developing sleeve 41 is used as one electrode of the electrode pair. However, the developing sleeve 41 is not used as the electrode of the remaining toner amount detecting means, and a separate electrode is provided. Is also possible. In this case, the degree of freedom in designing the electrode arrangement is increased. That is, at least an antenna member for detecting the developer amount (toner amount) using the electrostatic capacity is required for the developer container and the developing device.

3. About the antenna member The antenna member 43 of the present embodiment is formed of a nonmagnetic or diamagnetic conductive resin sheet so as not to adhere the magnetic toner, and is disposed to face the developing sleeve 41 vertically below. ing. Specifically, the antenna member 43 is bonded and fixed by insert molding near the developing sleeve 41 on the bottom surface of the inner wall of the developer container 46. In the present embodiment, when the conductive sheet member constituting the antenna member 43 is mounted on the developer container 46 so that the electrostatic capacity can be detected more appropriately, a part of the conductive sheet member is part of the developing sleeve 41 in the direction of gravity. (Area A in FIG. 9). In particular, when the antenna member 43 is in the vicinity of the lower part of the developing sleeve 41 and the toner easily accumulates on the electrode surface due to gravity, the remaining amount of toner can be accurately determined by using a conductive resin sheet containing resin. The effect that it can be measured becomes remarkable. This is because the conductive resin sheet containing a resin does not cause magnetic toner to adhere thereto. Also in this embodiment, the conductive resin sheet is provided below the developing sleeve 41 in the direction of gravity. However, the antenna member 43 can also be used in such an arrangement that electrodes are juxtaposed in the horizontal direction with respect to the developer carrying member, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2007-264612. Further, as will be described in detail later, the conductive resin sheet is disposed so as to contact a contact (not shown) disposed in front of the paper surface of FIG. The toner remaining amount detecting device 134 is connected to the ground.

  In the above configuration, by applying a bias to the developing sleeve 41 by the developing power source 131, the electrostatic capacity between the developing sleeve 41 and the antenna member 43 can be detected by the toner remaining amount detecting device 134. In the configuration of the present embodiment, sequential remaining amount detection is performed to sequentially detect the capacitance during printing.

  FIG. 12 shows a cross-sectional view of the conductive resin sheet 24. Here, a configuration in which a carbon material is dispersed in a resin, a configuration in which another resin layer is sandwiched between resin layers in which the carbon material is dispersed, and a configuration in which a carbon material is applied to the surface of the resin layer on the developer carrier side Will be explained.

  FIG. 12 (a) shows a conductive resin sheet 24 having a three-layer structure in which a resin layer of PS resin 24d is sandwiched between conductive layers 24c (20 μm to 40 μm) in which carbon black is mixed with PS resin and dispersed. In this case, the conductive layer becomes the electrode portion, and the entire conductive resin sheet becomes the electrode. The electrical connection with the outside can be considered as follows. That is, when the conductive resin sheet is cut, the conductive layers on both sides are deformed and connected. It is conceivable to connect an external electrical contact to that part. Further, it is also possible to use a conductive resin sheet 24 having a single layer structure (single layer structure) in which carbon black 24e is mixed with EVA resin 24d as shown in FIG. In this case, the whole becomes an electrode part. Furthermore, a conductive resin sheet 24 having a two-layer structure in which carbon black 24e is printed on PS resin 24d as shown in FIG. 12C can also be used.

In this embodiment, a flexible single-layer conductive resin sheet in which carbon black is dispersed in the EVA substrate shown in FIG. 12B is used. The carbon black content was 35% (30 to 40)% wt carbon black in mass% concentration dispersed in EVA. Carbon black content should just be disperse | distributed so that the resistance measured by the below-mentioned measuring method may become 10 < ³ > -10 < ⁵ > (omega | ohm) for the spike current countermeasure mentioned later. The total thickness t of the conductive resin sheet 24 depends on the shape of the affixing surface of the developer container 46, but from the viewpoint of ease of affixing processing, a thickness t = 0.05 to 0.3 mm is used. Is preferred. In this embodiment, it was set to 0.1 mm. Further, although carbon black has been described as a carbon material that imparts conductivity, it is also possible to impart conductivity with graphite, carbon fiber, carbon nanotube, or the like in addition to carbon black.

  FIG. 14A is a plan view showing the antenna member 43 of this embodiment in more detail. In the present embodiment, the antenna member 43 is predetermined in each of a longitudinal direction substantially parallel to the longitudinal direction (rotation axis direction) of the developing sleeve 41 and a short direction intersecting the longitudinal direction (substantially orthogonal in the present embodiment). A plan view having a length of λ has a rectangular portion. In addition, a developer container is used to conduct the rectangular portion from the end in the short direction far from the developing sleeve 41 to the contact (not shown) of the apparatus main body 110 at the end in the front direction of the paper in FIG. The conductive resin sheet is extended to the outside of 46. In other words, in the present embodiment, a rectangular region as shown in FIG. 14A of the antenna member 43 is the measurement unit 43A. Further, an extended region surrounded by a dotted line in FIG. 14A of the antenna member 43 is a contact portion 43 </ b> B serving as an electrical contact between the antenna member 43 and the apparatus main body 110. The contact portion 43 </ b> B is connected to the ground via a contact (not shown) of the apparatus main body 110 and a toner remaining amount detection device 134 disposed in the apparatus main body 110. FIG. 15 is a perspective view showing the developing device frame (especially the lower frame member 40A) of the present embodiment. FIG. 15A is the inside of the developer container 46, and FIG. Shows the outside. As shown in FIG. 15, the measurement portion 43 </ b> A of the antenna member 43 is disposed on the developing frame 40 so as to face the developing sleeve 41, but the contact portion 43 </ b> B is disposed on the outside of the developing frame 40. Yes. That is, the conductive resin member has a shape that extends to the outside through the inside of the developing device frame 40, and forms the contact portion 43B on the outside. In the present embodiment, the developer container 46 is formed by welding two frames by ultrasonic welding, but the conductive resin member is hidden outside the frame body inside the welded portion, A part of the conductive resin member is disposed outside the frame. A part of the conductive resin member exposed to the outside of the frame extends from the inside of the welded portion beyond the welded portion toward the outside of the welded portion. By doing in this way, the contact part 43B can be formed, without receiving the influence of a welding part.

  In the present embodiment, the width in the longitudinal direction (L1 in FIG. 14A) of the rectangular measurement portion 43A of the antenna member 43 is 216 mm which becomes a print guarantee region (image region), and is perpendicular to the longitudinal direction. The width in the short direction is 15 mm. In the present embodiment, the thickness of the antenna member 43 is 100 μm.

  Although the present embodiment is insert molding, when the insert molding is performed, the antenna member 43 is compatible or bonded and fixed to the inner wall of the developing container 46 with higher accuracy than the fixing of the double-sided tape in the positional accuracy of the conductive resin sheet 24. Can do. As a result, the distance accuracy between the developing sleeve 41, which is an electrode, and the antenna member 43 is improved, leading to an improvement in the detection accuracy of the developer amount. In particular, the fixing method according to the first embodiment is preferable.

  On the other hand, when the EVA conductive resin sheet 24 is insert-molded in the developing container 46, the following phenomenon may occur due to the difference in thermal shrinkage between the conductive resin sheet 24 and the developing container 46. As a first phenomenon, when the shrinkage amount of the developer container 46 is larger than the shrinkage amount of the conductive resin sheet, the conductive resin sheet 24 will wave after cooling. As a result, the distance accuracy with respect to the developing sleeve 41 is lowered, and the detection accuracy of the developer amount is lowered. The second phenomenon is when the contraction amount of the conductive resin sheet is larger than the contraction amount of the developer container 46 and when the rigidity of the developer container 46 is smaller than the contracting force of the conductive resin sheet. Is deformed. As a result, the distance accuracy with respect to the developing sleeve 41 is lowered, and the detection accuracy of the developer amount is lowered. Further, the blowout prevention sheet 32 undulates and the toner leaks.

  In order to suppress the above phenomenon, for example, the contraction amount of the conductive resin sheet is larger than the contraction amount of the developer container 46, and the rigidity of the developer container 46 is larger than the contracting force of the conductive resin sheet. The molding is preferably completed while the conductive resin sheet is pulled while the conductive resin sheet is in close contact with the developer container 46. As a result of the examination, the Young's modulus of the conductive resin sheet 24 is 0.2 to 0.3 GPa and the sheet thickness is 0.1 mm with respect to the HIPS developer container 46 having a Young's modulus of 2.5 to 3.5 GPa and a thickness of 1.5 mm. It was found that the above conditions can be satisfied by doing so. With the above setting, the conductive resin sheet 24 is not corrugated and the developing container 46 is not deformed, and can be molded while maintaining the distance accuracy with the developing sleeve 41, and the detection accuracy of the developer amount can be improved. Become. In view of the above, in the present embodiment, the thickness of the sheet is 0.1 mm, and the Young's modulus is 0.25 GPa.

  The resin of the conductive resin sheet 24 is bonded to the developer container 46 and does not have to adhere magnetic toner. When the HIPS developer container 46 is used, PS other than EVA may be used. . Further, it is only necessary to have a conductive layer in which carbon black is dispersed on the surface in contact with the toner to be measured, and the same effect can be obtained with a sheet having a multi-layer structure as shown in FIGS. 12 (a) and 12 (c). .

  The conductive resin sheet 24 is preferably arranged in the short direction in the vicinity of the developing sleeve 41. This is because the toner that is regulated and dropped by the developing blade 42 is accurately detected as the remaining toner.

4). Comparison between Example and Comparative Example (Configuration of Example 3)
Example 3 is configured according to the present embodiment, and has a resistance of 10 ⁵ Ω or less (10 ⁵ Ω, 10 ⁴ Ω, 10 ³ Ω, 0 Ω) when measured by the measurement method (1) described later of the conductive resin sheet. )belongs to.

(Configuration of Comparative Example 3)
The antenna member 43 differs in the comparative example 3 compared with the structure of Example 3. As the antenna member 43 in Comparative Example 3, SUS304 which was rolled into a thickness of 500 μm and cut into a strip shape of 216 mm in the longitudinal direction and 15 mm in the lateral direction was used. Although SUS304 is non-magnetic, application of stress causes the austenite layer to undergo martensitic transformation and become magnetized. The antenna member 43 of Comparative Example 3 is also stressed and magnetized by rolling and cutting.

(Configuration of Example 4)
Example 4 is configured according to the present embodiment, but the antenna member 43 is different from Example 3. The shape, material, and fixing method of the antenna member 43 in the fourth embodiment are the same as those in the third embodiment. However, the conductive resin sheet 24 in which the amount of carbon black dispersed in the EVA resin was reduced was used. This conductive resin sheet 24 has a resistance of 10 ⁶ Ω when measured according to the measurement method (1) described later.

(Evaluation method)
The toner remaining amount is obtained by the following toner remaining amount calculating method.

  FIG. 10 shows an example of the relationship between the remaining amount of toner and the capacitance according to the present embodiment. The vertical axis represents the electrostatic capacity detected by the toner remaining amount detecting means 134, and the horizontal axis represents the remaining toner amount (%). In the configuration of the present embodiment, the capacitance does not change from the initial time (100%) to the time point of 20% (dotted line A). This is because the toner amount (developer amount) between the developing sleeve 41 and the antenna member 43 does not change because the toner remains sufficiently. When the remaining amount of toner becomes 20% or less, the capacitance decreases linearly as the remaining amount of toner decreases. This indicates that the toner amount (developer amount) between the developing sleeve 41 and the antenna member 43 changes according to the remaining amount of toner.

Here, new time, the difference between the electrostatic capacitance _{C 0} and the remaining amount of toner 100% (Full) capacitance Cs when the 20% in a state where no toner between the developing sleeve 41 and the antenna member 43 Was ΔE ₀ . Further, when the average value of the electrostatic capacity during printing of one image is output as the electrostatic capacity C, there is no toner between the electrostatic capacity during image printing and the developing sleeve 41 and the antenna member 41. The difference from the electrostatic capacity C ₀ in the state was defined as ΔE. Therefore, the current remaining toner amount is calculated by the following equation (1).
Current toner remaining amount = 20% × ΔE / ΔE ₀ Formula (1)

  The detection result is transmitted to the user by being displayed on a display unit in the image forming apparatus or a monitor 21 of a personal computer.

(Evaluation results)
<Comparison of detection accuracy of remaining toner amount between Example 3 and Comparative Example 3>
FIG. 11A shows the relationship between the remaining toner amount actually measured by performing an endurance test in Example 3 and the output electrostatic capacity. FIG. 11B shows the relationship between the remaining amount of toner actually measured through an endurance test and the output capacitance in Comparative Example 3. The horizontal axis is the remaining amount of toner actually remaining in the developer container 46, and the vertical axis is the electrostatic capacity.

  In FIG. 11A, which is Embodiment 3, there is no change in capacitance when the remaining amount of toner is between 100% and 20%. In the area where the remaining amount of toner is 20% or less, the electrostatic capacity decreases linearly as the remaining amount of toner decreases. Here, at the timing of “1” in FIG. 11A, an image in which the toner is not developed in a vertical band shape on the image (hereinafter, also referred to as “blank image”) is generated. At this time, no toner adhered to the antenna member 43. Therefore, even if the developing device 4 is shaken at the timing “1”, the white spots are not recovered.

  On the other hand, as shown in FIG. 11B, in Comparative Example 3, as in Example 3, there is no change in capacitance when the remaining amount of toner is between 100% and 20%. In the area where the remaining amount of toner is 20% or less, the electrostatic capacity decreases linearly as the remaining amount of toner decreases. However, a blank image occurred at a timing when the remaining amount of toner was larger than that in Example 3 (“2” in FIG. 11B). When the antenna member 43 was confirmed at this time, the toner adhered to the antenna member 43. Even if the same toner amount (developer amount) remains between the electrodes, the toner adhering to the antenna member 43 cannot be developed. Therefore, white spots have occurred at timing “2” when the detected toner amount (developer amount) is large.

  The reason why the toner adheres to the antenna member 43 is that the antenna member 43 is magnetized. Further, when the toner adhering to the antenna member 43 is sucked and the remaining amount of toner is measured again, the detected remaining amount of toner is “3” as in the third embodiment. The image at that time was a blank image as in the case of the timing “2”. As described above, in Comparative Example 3, the generation timing of the white spot image varies depending on the amount of toner attached to the antenna member 43. Further, the amount of toner attached to the antenna member 43 differs for each developing device. Therefore, the detection accuracy of the remaining toner amount is lowered.

  Thus, in Example 3, since the toner did not adhere to the antenna member 43 at the timing of “1”, the toner between the electrodes can be used with good reproducibility. That is, it is possible to suppress a decrease in detection accuracy of the remaining amount of toner due to the toner adhering to the antenna member 43, and the detection accuracy of the remaining amount of toner is improved.

<Comparison of detection accuracy of remaining toner amount between Example 3 and Example 4>
Table 1 shows the relationship between the resistance of the conductive resin sheet measured by the measurement method (1) described later and the detection accuracy of the remaining amount of toner. The remaining amount detection ○ indicates that the remaining amount of toner has been detected with high accuracy, and the remaining amount detection Δ indicates that it is possible to detect but the detection signal is small, so that it is preferable to perform signal processing or the like. Furthermore, the remaining amount detection x indicates that it could not be detected.

From Table 1, in Example 3 in which the resistance of the conductive resin sheet was 10 ⁵ Ω or less, the detection accuracy of the remaining amount of toner was good. On the other hand, when the resistance of the conductive resin sheet becomes 10 ⁶ Ω as in Example 4, the detection signal becomes small, and some signal processing or the like is necessary to accurately grasp the capacitance. This is because the resistance of the conductive resin sheet is high, the current flowing through the remaining toner detection device 134 is reduced, and the electrostatic capacity is difficult to detect. Therefore, the resistance of the conductive resin sheet is desirably 10 ⁵ Ω or less. The resistance value per unit length at this time was 420 Ω / mm.

(Configuration of Example 5)
Example 5 is configured according to the present embodiment, and has a resistance of 10 ³ Ω or more when measured by the measurement method (2) described later of the conductive resin sheet 24.

  FIG. 13 shows a toner remaining amount detection circuit as disclosed in, for example, Japanese Patent Application Laid-Open No. 2007-264612. In the case of this toner remaining amount detecting circuit, there is no mechanism (protective resistance) for reducing the amount of current flowing in the toner remaining amount detecting circuit when a spike current such as a shake at the time of applying an AC voltage flows. For this reason, there is a concern that the detector of the toner remaining amount detecting device 134 may malfunction. Therefore, attention is also paid to the point of solving the malfunction of the detector caused by the spike current.

In this embodiment, the antenna member 43 adjusts the amount and dispersion of carbon black so that the resistance measured by the measurement method (2) described later is 10 ³ Ω or more (10 ³ Ω, 10 ⁴ Ω). did.

(Configuration of Comparative Example 4)
As the antenna member 43 of Comparative Example 4, a commonly used antenna member 43 of SUS304 was used. The resistance in the measuring method (2) described later was 0Ω.

(Evaluation results)
<Spike current reduction comparison between Example 5 and Comparative Example 4>
Table 2 shows the relationship between the resistance measured by the measurement method (2) described later and the spike current reduction effect. The relationship of ○ × Δ in Table 2 is the same as in Table 1.

From Table 2, when the resistance of the conductive resin sheet was 10 ³ Ω or more, both the detection accuracy of the remaining amount of toner and the effect of reducing the spike current were good results. In addition, the resistance value per unit length at this time was 30 Ω / mm. On the other hand, in the case of Comparative Example 4 having a resistance of 0Ω, the effect of reducing the spike current is low, and there is a possibility that the detection accuracy of the toner remaining amount of the toner remaining amount detecting device 134 is lowered.

Above, from the results of Examples 3-5, the resistance of the conductive resin sheet, measuring method (1) resistance value measured in the 10 ⁵ Omega or less, the resistance value measured by the measuring method (2) is 10 ³ Omega By doing so, the spike current can be reduced while maintaining the detection accuracy of the remaining amount of toner. That is, the resistance of the conductive resin sheet is preferably 10 ³ Ω or more and 10 ⁵ Ω or less.

5). Method for Measuring Resistance of Conductive Resin Sheet A method for measuring the resistance of the conductive resin sheet in the present embodiment will be described.

  The resistance of the conductive resin sheet varies depending on the distance from the contact. Therefore, the resistance of the conductive resin sheet is defined by the following two measurement methods.

<Measurement method (1)>
The resistance between the measurement point A and the measurement point B shown in FIG. The measurement point A is the tip of the contact portion 43B (the surface on the same side as the surface in contact with the developer of the measurement portion 43A). The measurement point B is a point (a point on the developing sleeve 41 side in the short side direction) that is farthest from the measurement point A in the measurement unit 43A (surface on the side in contact with the developer). Conductive grease is applied to each measurement point in a circle with a diameter of 5 mm, and resistance measurement is performed between measurement point A and measurement point B using Fluke 87V manufactured by Fluke.

<Measurement method (2)>
The resistance between the measurement point A and the measurement point C shown in FIG. As described above, the measurement point A is the tip of the contact portion 43B (the surface on the same side as the surface in contact with the developer of the measurement portion 43A). The measurement point C is a point closest to the measurement point A (a point on the developing sleeve 41 in the short side direction) in the measurement unit 43A (surface on the side in contact with the developer). Conductive grease is applied to each measurement point in a circle with a diameter of 5 mm, and resistance measurement is performed between measurement point A and measurement point C using Fluke 87V manufactured by Fluke.

  In this embodiment, when magnetic toner is used, the problem is that the toner adheres to the electrode. However, the configuration itself is a novel configuration, and even with non-magnetic toner that does not cause the adhesion problem, the electrostatic capacity A conductive sheet can be used as a toner remaining amount detecting member using the toner.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. In this embodiment, elements having the same functions and configurations as those in the first and second embodiments or corresponding to those in the first and second embodiments are denoted by the same reference numerals, and detailed description thereof is omitted. .

  In the present embodiment, a preferred arrangement of antenna members will be described in order to improve the detection accuracy of the amount of developer by a capacitance detection method using a resin antenna member.

1. Developing Device FIG. 16 is a schematic cross-sectional view of the developing device 4 in the present embodiment.

  Here, in the present embodiment, the seal member 48 is bonded to a seal welding rib 47 provided at the bottom of the accommodating portion 40a in the vicinity of the toner supply port 46d. For this reason, when the bottom surface of the container 40a is flat, the seal welding rib 47 may obstruct the circulation of the toner T from the toner chamber 46b to the developing chamber 46a. In order to avoid this, in the present embodiment, a convex portion 46e is provided between the developing sleeve 41 and the stirring member 45 at the same height as or higher than the seal welding rib 47 when the developing device 4 is in use. It has been. In the present embodiment, the convex portion 46e is provided on the bottom surface of the toner chamber 46b adjacent to the toner supply port 46d. The convex portion 46 e protrudes toward the inside of the developer container 46 and protrudes toward the developing sleeve 41. The convex portion 46 allows the toner T to be sent to the vicinity of the developing sleeve 41 by the stirring member 45 without any stagnation even if the seal welding rib 47 is present. Further, the bottom surface of the toner chamber 46b opposite to the developing sleeve 41 with respect to the convex portion 46e is a concave portion 46f. The stirring sheet member 45b appropriately enters the recess 46f when the stirring member 45 is driven to rotate. Then, the toner T sent in the direction of the convex portion 46e by the stirring sheet member 45b corresponds to the magnetic pole S2 of the magnet roller 44 so as to be splashed up by the stirring sheet member 45b released in the vicinity of the apex of the convex portion 46e. To the vicinity of the surface of the developing sleeve 41. Thus, the toner T collected on the bottom surface of the toner chamber 46b can be more reliably conveyed to the vicinity of the developing sleeve 41. In the present embodiment, the seal member 48 is attached to the stirring shaft 45 a of the stirring member 45.

2. Next, the detection device 130 according to the present embodiment will be described. The basic configuration and operation of the detection device 130 in the present embodiment are substantially the same as those in the first and second embodiments.

  FIG. 17 shows an outline of the flow of processing for detecting the amount (remaining amount) of the toner T and notifying the user or the like. First, the controller unit 133 starts an image printing operation (S101). Next, the controller unit 133 obtains a result of measuring the capacitance by the capacitance detection circuit 132 during image printing (S102). Next, the controller unit 133 refers to the detection result of the electrostatic capacitance and the data table to obtain the current remaining amount of toner T (S103). Next, the controller unit 133 displays information on the obtained remaining amount of toner T on a display unit (not shown) provided in the apparatus main body 110 or a monitor (not shown) of a personal computer, thereby displaying the user. To inform.

  Here, as shown by a solid line in FIG. 19 to be described later, the transition of the electrostatic capacity due to the consumption of the toner T indicates the current remaining amount of the toner T from the electrostatic capacity detected by the electrostatic capacity detecting circuit 132. It is obtained in advance as a data table for obtaining. In this embodiment, this information is stored in the cartridge-side memory 13 (FIG. 2) provided in the process cartridge 120. Such a relationship between the amount of toner T and the capacitance can be obtained, for example, as follows. Each time a predetermined amount of toner T is sequentially put into the developer container 46 from the empty state, the process cartridge 120 provided with the developer container 46 is installed in the image forming apparatus 100, and a pre-multi-rotation operation is performed. The capacitance is measured by the capacitance detection circuit 132. The pre-multi-rotation operation is a preparatory operation performed until image formation becomes possible after the image forming apparatus 100 is powered on.

3. Configuration of antenna member and manufacturing method As a result of the study by the present inventors, the amount of the developer is obtained even when insert molding is performed using a conductive resin sheet which is a resin electrode and is integrally molded with the developing frame. In some cases, the accuracy of detection decreased. For example, even when it is notified that the developer has been used up, a relatively large amount of developer may remain. This is due to the following reason. That is, even when the conductive resin sheet can be placed in the mold with high positional accuracy when the developing frame is molded, the conductive resin sheet heated by the heat of the injected resin is thermally contracted by the cooling (curing) process. . As a result, the positional accuracy of the end portion of the conductive resin sheet varies, and the distance between the developing sleeve as the other electrode and the end portion of the conductive resin sheet changes. As a result, even when the developer amount is the same, the detection result of the electrostatic capacitance is different, and the detection accuracy of the developer amount is lowered.

  Therefore, in this embodiment, as will be described in detail later, even if the distance between the antenna member 43 and the developing sleeve 41 varies as described above, it is possible to suppress a decrease in the detection accuracy of the amount of toner T. In addition, the arrangement of the antenna member 43 is set.

  FIG. 18 is a cross-sectional view of the vicinity of the conductive resin sheet in the mold 201 for molding the developing frame 40 on which the conductive resin sheet constituting the antenna member 43 is arranged. In the present embodiment, the air suction portion 222 is disposed on the end portion side of the conductive resin sheet 24 on the gate 232 side, and the conductive resin sheet 24 is adsorbed to the first mold 202 on the end portion side. Thereby, it is possible to easily suppress wrinkles caused by the conductive resin sheet 24 being stretched by heat when the resin is injected into the mold 201 and misalignment caused by the thermal contraction of the conductive resin sheet 24 during cooling. . The positioning by air suction may be performed as long as the position of the conductive resin sheet 24 does not move due to the pressure of the injected resin, and substantially the entire surface of the conductive resin sheet 24 may be sucked by air.

  In the present embodiment, the conductive resin sheet 24 is a conductive resin sheet having a single-layer structure in which carbon black is dispersed as a conductive material in an EVA base to provide conductivity. The conductive resin sheet 24 having a multi-layer structure generally has a thin conductive layer. For this reason, it is desirable to pay attention to wear when, for example, a metal contact is brought into contact with the conductive resin sheet 24 in order to establish conduction with the ground electrode.

  In the present embodiment, the measurement part of the conductive resin sheet 24 is substantially rectangular, the length in the longitudinal direction is 216 mm, which is the same as the image area (print guarantee area) in the direction substantially orthogonal to the image transport direction, and the short direction Is a rectangle with a length of 40 mm. The thickness of the conductive resin sheet 24 is 100 μm. Further, the developing device frame 40 (particularly the bottom of the housing portion 40a in the vicinity of the antenna member 43) has a thickness of 1.5 mm.

4). Arrangement of Antenna Member Next, the arrangement of the antenna member 43 will be described. Even when the manufacturing method described so far is used, the position of the antenna member 43 may be shifted. In particular, the position of the end of the antenna member 43 in the short direction, which is a direction intersecting (substantially orthogonal in the present embodiment) with the longitudinal direction (axial direction) of the developing sleeve 41 as the other electrode, may be shifted. There is. This is because the tolerance of the mounting position when the conductive resin sheet 24 is installed in the mold 201 (first mold 202), or the conductive resin sheet 24 generated in the process from when the resin is injected into the mold 201 until it is cooled. This is due to tolerance of shape deformation (heat shrinkage, etc.). An end of the developing sleeve 41 in the short direction (hereinafter simply referred to as “end B”), which is the end of the antenna member 43 closer to the developing sleeve 41 when viewed in the longitudinal direction (axial direction) of the developing sleeve 41. If the position is shifted, the detection accuracy of the amount of toner T tends to be lowered (FIG. 18).

  In the present embodiment, in the short direction of the antenna member 43, the end B is not positioned by air suction compared to the other end (the end on the gate 232 side during molding). The amount by which the distance to the sleeve 41 changes tends to increase (FIG. 18).

  Therefore, in the present embodiment, as shown in FIG. 21A, when viewed in the longitudinal direction (axial direction) of the developing sleeve 41, the closest contact point (hereinafter referred to as the antenna member 43 and the developing sleeve 41 on the antenna member 43). , Simply referred to as “nearest contact point A”) is set as follows. That is, the closest contact A is set to a position other than the end of the antenna member 43 (more specifically, the end B closer to the developing sleeve 41).

  Thereby, even if the distance between the antenna member 43 and the developing sleeve 41 varies due to the contraction of the conductive resin sheet 24 or the like, it is possible to suppress a decrease in detection accuracy of the amount of toner T.

5). Effect (Relationship between toner accumulation and detected capacitance)
FIG. 19 shows the relationship between the remaining amount of toner and the capacitance. The horizontal axis is the toner remaining amount, and the vertical axis is the detected capacitance. C ₀ is a capacitance detected when the remaining amount of toner is 0%. In the present embodiment, when the capacitance reaches C ₀ , the user is notified that the toner has run out, assuming that a whiteout image may occur.

The solid line in FIG. 19 indicates the relationship between the remaining amount of toner and the electrostatic capacity obtained in advance as described above in the configuration of the present embodiment. Further, the broken line is detected as the remaining amount of toner actually remaining in the developer container 46 when the position of the antenna member 43 is shifted and, for example, the distance between the antenna member 43 and the developing sleeve 41 is increased. It is a relationship with capacitance. Here, the difference between the solid line and the broken line is ΔC. The reason why the broken line comes below the solid line is that the distance between the antenna member 43 and the developing sleeve 41 is increased, and the detected capacitance value is low despite the same toner remaining amount. is there. When the capacitance C ₀ is detected, the remaining amount of toner is 0% on the solid line. However, in the broken line, the remaining amount of toner is not 0%, and a large amount of toner remains by ΔM. As described above, when the distance between the antenna member 43 and the developing sleeve 41 changes, the detected capacitance value with respect to the remaining amount of toner is shifted by ΔC. Therefore, the remaining amount of toner when the capacitance C ₀ is detected changes by ΔM.

  In FIG. 19, in section 1 from the remaining amount of toner m1 to m2, the capacitance is constant regardless of the remaining amount of toner. FIG. 20A is a schematic cross section in the vicinity of the antenna member 43 schematically showing how toner is accumulated in the developer container 46 at this time. This figure is seen in the longitudinal direction (rotational axis direction) of the developing sleeve 41 (hereinafter the same applies to FIGS. 20 to 25). In FIG. 20A, broken lines R <b> 1 and R <b> 2 indicate tangent lines of the developing sleeve 41 that pass through the end of the antenna member 43 in the short direction. A region surrounded by the broken line R1, the broken line R2, the surface of the developing sleeve 41 and the surface of the antenna member 43 is a toner remaining amount measurement region (hereinafter, the same applies to FIGS. 20 to 23). In FIG. 20A, H1 and H2 respectively indicate the toner surface of the toner. When the process cartridge 120 is new, the surface of the toner is at the position H1, and as the toner is consumed by image formation, it shifts toward the position H2. Until the toner surface reaches the H2 position, the measurement area of the remaining amount of toner is filled with toner, so that the electrostatic capacitance remains constant regardless of the remaining amount of toner. At this time, the circulation of the toner is as indicated by arrow T1 → arrow T2 → arrow T3. Specifically, the toner sent to the vicinity of the developing sleeve 41 by the stirring member 45 is supplied to the surface of the developing sleeve 41 by the magnetic pole S2 of the magnet roller 44 (arrow T1). The toner supplied to the surface of the developing sleeve 41 is conveyed to the contact portion between the developing blade 42 and the developing sleeve 41 by the rotation of the developing sleeve 41 (arrow T2). The toner regulated by the developing blade 42 and peeled off from the surface of the developing sleeve 41 is returned to the toner chamber 46b by the stirring member 45 (arrow T3).

  In FIG. 19, in section 2 from the remaining toner amount m2 to 0%, the electrostatic capacity decreases as the remaining toner amount decreases. FIG. 20B is a schematic cross-section in the vicinity of the antenna member 43 schematically showing how toner is accumulated in the developer container 46 at this time. In FIG. 20B, H3 and H4 indicate the toner surface of the toner, respectively. In FIG. 19, when the remaining amount of toner is less than m2, the surface of the toner is at positions H3 and H4. The surface of the toner immediately before the occurrence of the white spot image is H4. Since the toner surface H3 enters the measurement area of the remaining amount of toner, the capacitance decreases as the toner is consumed. Eventually, as indicated by the toner surface H4, the toner accumulates in the vicinity of the contact area between the developing sleeve 41 and the developing blade 42 due to the magnetic poles of the magnet roller 44. At this time, in addition to the circulation in the section 1, the toner circulates as well as the toner falling near the antenna member 43 as indicated by the arrow t4. Finally, when the surface of the toner is indicated by H4, the toner moves in the contact area between the developing sleeve 41 and the developing blade 42 as the developing sleeve 41 rotates as indicated by the arrow t1, the arrow t2, and the arrow t3. It circulates only in the nearby toner reservoir.

(Positional relationship between antenna member and developing sleeve)
As the position of the antenna member 43 varies, the detection result of the capacitance also varies. In particular, as the distance between the developing sleeve 41 and the antenna member 43 is shorter, the detection sensitivity of the electrostatic capacity is increased. Therefore, the position accuracy closer to the developing sleeve 41 of the antenna member 43 is required to be high.

  FIG. 21A is a schematic cross-sectional view of the vicinity of the antenna member 43 showing the positional relationship between the developing sleeve 41 and the antenna member 43 in the present embodiment. In the present embodiment, in the antenna member 43, the closest point A is a position other than the end B. More specifically, in the antenna member 43, the closest point A is a position between the end B and the opposite end. In this embodiment, the closest distance between the closest point A and the developing sleeve 41 is 5 mm, and the distance between the closest point A and the end B is 3 mm. The closest distance between the end B and the developing sleeve 41 is 5.2 mm.

  The specific arrangement of the antenna member 43 is not limited to that of the present embodiment. On the antenna member 43 (on the second electrode), the closest point A between the developing sleeve 41 and the antenna member 43 is not the end B on the developing sleeve 41 side (first electrode side) (that is, other than the end). And the antenna member 43 may be disposed. It is preferable that the distance between the closest position A and the end B is greater because the influence of the shake of the arrangement of the end B on the detection accuracy of the remaining amount of toner becomes smaller.

(Configuration of Comparative Example 5)
FIG. 22A is a schematic cross-sectional view of the vicinity of the antenna member 43 showing the positional relationship between the developing sleeve 41 and the antenna member in Comparative Example 5. FIG. The configuration of Comparative Example 5 is substantially the same as that of the present embodiment except for points specifically mentioned below.

  In Comparative Example 5, an antenna member 43, which is a plate-like member (SUS sheet metal) formed of SUS (stainless steel), is bonded and fixed to the developing frame 40 with a double-sided tape. In Comparative Example 5, the closest point A to the developing sleeve 41 and the end B on the developing sleeve 41 side of the antenna member 43 coincide with each other.

(Evaluation of this embodiment and Comparative Example 5)
The end B side of the antenna member 43 of the present embodiment shown in FIGS. 21A and 22A and Comparative Example 5 is made smaller in the direction of arrow Z (the other end side) in the drawing, thereby reducing the end. The arrangement of part B was changed by 2 mm. Then, the influence of the position accuracy on the detection accuracy of the toner remaining amount was evaluated.

  FIG. 21B shows the relationship between the remaining amount of toner actually remaining in the developer container 46 and the detected capacitance in the configuration of the present embodiment. FIG. 22B shows the relationship between the remaining amount of toner actually remaining in the developer container 46 and the detected capacitance in the configuration of Comparative Example 5. The solid lines in FIGS. 21 (b) and 22 (b) indicate the remaining amount of toner and the electrostatic capacity in the arrangement of the antenna member 43 of the present embodiment and the comparative example 5 shown in FIGS. 21 (a) and 22 (a), respectively. Relationship. The broken lines indicate the relationship between the remaining amount of toner and the capacitance when the position of the antenna member 43 is shifted by 2 mm as described above.

  In the solid lines of FIGS. 21B and 22B, the detected capacitance does not change in the section 1 where the remaining amount of toner is from m1 to m2. This is because the toner surface is between H1 and H2, as described with reference to FIG. As described above, since the amount of toner in the measurement region does not change even when the remaining amount of toner is reduced, the detected capacitance is constant. In this embodiment, m2 is about 20% of the remaining amount of toner.

  Further, in the solid lines in FIGS. 21B and 22B, in the section 2 in which the remaining amount of toner is from m2 to 0%, the detected capacitance is linear with respect to the remaining amount of toner. . This is because, as described with reference to FIG. 20B, the amount of toner in the measurement region decreases when the toner surface moves from the position H3 to the position H4.

  The broken lines in FIGS. 21B and 22B also change with the same tendency as the solid line, but the capacitance value detected as a whole is smaller than in the case of the solid line. As can be seen from FIGS. 21A and 22A, the antenna member 43 is moved away from the developing sleeve 41 due to the position of the end B of the antenna member 43 being shifted, and the same toner remaining amount is obtained. This is because the capacitance value to be detected is low despite the fact. When the detected capacitance decreases, the remaining amount of toner obtained by referring to the data table decreases.

  Here, when the difference (change amount) ΔC between the solid line and the broken line is compared between the present embodiment shown in FIG. 21B and the comparative example 5 shown in FIG. 22B, the comparative example 5 is larger. There are the following two reasons why ΔC is larger than that of the present embodiment in Comparative Example 5.

  Reason 1: Since the closest contact A having the highest capacitance detection sensitivity in the antenna member 43 coincides with the end B, when the position of the end B is shifted by 2 mm, the highest capacitance detection sensitivity is obtained. The closest distance affected will change. As a result, the detected value of capacitance changes greatly (decreases), thereby increasing ΔC.

  Reason 2: The antenna member 43 is reduced by 2 mm in the direction of arrow Z in the figure, so that the capacitance measurement range is narrowed and the capacitance detection value is reduced.

On the other hand, in the present embodiment, the situation of reason 1 described above is different. In the present embodiment, the closest point A and the end B, which have the highest capacitance detection sensitivity in the antenna member 43, do not match. For this reason, even if the position of the end B is shifted by 2 mm, the closest distance that most affects the detection sensitivity of the capacitance does not change, so the detection value of the capacitance is relatively unaffected. As a result, in the present embodiment, ΔC becomes smaller by the above-described reason 1 than in the comparative example 5. Thus, the difference between the amount of toner remaining when the electrostatic capacitance C ₀ is a timing white spot image occurs is detected, than ΔM2 in Comparative Example 5, towards ΔM1 in this embodiment is reduced.

  As described above, in the present embodiment, the position of the closest point A and the end B of the antenna member 43 is shifted. As a result, even if the position of the end B of the antenna member 43 is shifted due to the displacement at the time of mounting, the tolerance of a single component, deformation such as heat shrinkage, etc., the detection accuracy of the remaining amount of toner is lowered. The remaining amount of toner can be reported with high accuracy until the toner is used up. Therefore, it is possible to suppress a decrease in detection accuracy of the amount of developer when a conductive resin sheet is used as an electrode for detecting capacitance. Therefore, it is possible to provide a developer container, a developing device, a process cartridge, and an image forming apparatus having a lower cost configuration while maintaining or improving the detection accuracy of the developer amount.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described. In this embodiment, elements having the same functions and configurations as those in the first to third embodiments or corresponding to those in the first to third embodiments are denoted by the same reference numerals, and detailed description thereof is omitted. . This embodiment is particularly a modification of the third embodiment.

  FIG. 23A is a schematic cross-sectional view of the vicinity of the antenna member 43 of the developing device 4 in the present embodiment. In this embodiment, the antenna member 43 is arrange | positioned at the convex part 46e formed in the bottom face of the accommodating part 40a. And in the antenna member 43, the nearest point A is arrange | positioned in the vertex vicinity of the convex part 46e. As a result, compared with the third embodiment in which the antenna member 43 is flat, even if the closest distance to the developing sleeve 41 is the same, the end B of the antenna member 43 (the end on the developing sleeve 41 side) The distance from the developing sleeve 41 is further increased. Therefore, as compared with the third embodiment, the influence of the shake of the position of the end portion B of the antenna member 43 becomes smaller.

  In this embodiment, the closest distance between the closest point A and the developing sleeve 41 is 5 mm, and the distance between the closest point A and the end B is 3 mm. The closest distance between the end B and the developing sleeve 41 is 6.8 mm, which is longer than that in the third embodiment.

  The evaluation of the present embodiment was performed in the same manner as in the third embodiment. FIG. 23B shows the relationship between the remaining amount of toner actually remaining in the developer container 46 and the detected capacitance in the configuration of the present embodiment. The solid line in FIG. 23B is the relationship between the remaining amount of toner and the capacitance in the arrangement of the antenna member 43 of this embodiment shown in FIG. In addition, the broken line is shifted by 2 mm in the arrangement of the end B by reducing the end B side of the antenna member 43 of the present embodiment in the direction of arrow Z (the other end side) in FIG. This is the relationship between the remaining toner amount and the electrostatic capacity.

  FIG. 23B shows that the capacitance detected with respect to the actual toner remaining amount becomes small due to the effect of shifting the position of the end B of the antenna member 43. Here, when the difference (change amount) ΔC between the solid line and the broken line is compared between the present embodiment shown in FIG. 23B and the comparative example 5 shown in FIG. 22B, the comparative example 5 is larger. In Comparative Example 5, the reason why ΔC is larger than that of the present embodiment is one of the following reasons in addition to the reasons 1 and 2 described above.

  Reason 3: By disposing the closest contact A on the convex portion 46e, the end B and the developing sleeve 41 are equal even when the closest distance is the same as in the case of the antenna member 43 that is flat as in Comparative Example 5. The distance between is far. Thereby, the influence which the shift | offset | difference of the edge part B has on the detection value of an electrostatic capacitance further decreases.

Thus, in this embodiment, ΔC is smaller than that of Comparative Example 5. As a result, the difference between the amount of toner remaining when the electrostatic capacitance C ₀ is a timing white spot image occurs is detected, than ΔM2 in Comparative Example 5, towards ΔM3 in this embodiment is reduced.

  Note that ΔC in the present embodiment is smaller than ΔC in the third embodiment, and ΔM3 in the present embodiment is smaller than ΔM1 in the third embodiment. This is also considered to be due to the above reason 3.

  As described above, according to the present embodiment, the same effects as those of the third embodiment can be obtained, and further, the closest contact A can be disposed on the convex portion 46e, thereby further suppressing the decrease in detection accuracy of the toner remaining amount. can do.

[Fifth Embodiment]
Next, another embodiment of the present invention will be described. In this embodiment, elements having the same functions and configurations as those in the first to fourth embodiments or corresponding to those in the first to fourth embodiments are denoted by the same reference numerals and detailed description thereof is omitted. . In particular, the present embodiment is still another modification of the third embodiment.

  In the third embodiment and the fourth embodiment, the remaining amount of toner that can be detected is 20% to 0%. This is because the toner amount in the measurement region is changed only when the remaining amount of toner is reduced to 20%. By bringing the antenna member 43 close to the developing sleeve 41, it is possible to accurately detect the vicinity of the remaining amount of toner of 0%. However, in this case, the measurement area of the remaining amount of toner may be small. Therefore, in order to detect the remaining amount of toner from the time when the remaining amount of toner is larger while maintaining the detection accuracy in the vicinity of 0% of the remaining amount of toner, the measurement area by the antenna member 43 can be increased (widened). desired.

  In the case of increasing the measurement area of the remaining amount of toner, conventionally, as in Comparative Example 6 (FIG. 25A) to be described later, a plurality of antenna members (such as SUS sheet metal) are attached to a developer container with double-sided tape or the like (for example 2 Sheet) is being pasted. In this case, each antenna member is connected to a capacitance detection circuit. However, in the case of such a configuration, the distance tolerance as described in the third embodiment is put on each attached antenna member, so that the detection result of the remaining amount of toner varies. Further, since a plurality of (for example, two) antenna members 43 are attached, the number of steps for manufacturing the developer container is larger than in the case of Comparative Example 5, for example, and the cost is increased.

  FIG. 24A is a schematic cross-sectional view of the vicinity of the antenna member 43 of the developing device 4 in the present embodiment. In the present embodiment, the antenna member 43 is continuously arranged from the convex portion 46e to the concave portion 46f formed on the bottom surface of the accommodating portion 40a. As a result, the antenna member 43 has two surfaces of the measurement region 1 and the measurement region 2 as measurement regions that face the developing sleeve 41 and can measure the capacitance. Further, the antenna member 43 has one non-measurement region in which the electrostatic capacity cannot be measured because it is a shadow of the convex portion 46e with respect to the developing sleeve 41 between the convex portion 46e and the concave portion 46f. As described above, in the present embodiment, the antenna member 43 has at least one convex portion protruding toward the developing sleeve 41 (first electrode side), and the closest contact point A is on this convex portion. In this embodiment, the antenna member 43 has at least one concave portion opposite to the developing sleeve 41 with respect to the convex portion, and a single antenna member 43 forms a plurality of surfaces facing the developing sleeve 41. doing.

  Specifically, in FIG. 24A, the broken line R1 indicates that the boundary line R4 of the area shaded by the convex portion 46e with respect to the developing sleeve 41 is in contact with the antenna member 43 on the developing sleeve 41 side ( This is a tangent line of the developing sleeve 41 passing through the vicinity of the apex of the convex portion 46e. A broken line R2 is a tangent to the developing sleeve 41 that passes through the end B of the antenna member 43 on the developing sleeve 41 side. A region surrounded by the broken line R1, the broken line R2, the surface of the developing sleeve 41, and the surface of the antenna member 43 is the measurement region 1 of the remaining amount of toner. In FIG. 24A, a broken line R3 is a tangent line of the developing sleeve 41 that passes through the end of the antenna member 43 opposite to the developing sleeve 41 side. A broken line R4 is a boundary line of a region that is a shadow of the convex portion 46e with respect to the developing sleeve 41. A region surrounded by the broken line R3, the broken line R4, the surface of the developing sleeve 41, and the surface of the antenna member 43 is a measurement region 2 of the remaining amount of toner. In FIG. 24A, a region surrounded by the surface of the antenna member 43 and the broken line R4 is a non-measurement region of the remaining amount of toner.

FIG. 24B shows the relationship between the remaining amount of toner and the electrostatic capacity obtained in advance as described above in the configuration of the present embodiment. The horizontal axis is the toner remaining amount, and the vertical axis is the detected capacitance. C ₀ is a capacitance detected when the remaining toner amount is 0% at which a blank image is generated.

  In FIG. 24B, in section 1 from the remaining amount of toner m1 to m2, the capacitance is constant regardless of the remaining amount of toner. At this time, the surface of the toner is at a position H5 in FIG. When the process cartridge 120 is new, the surface of the toner is above the position H5 and is shifted toward the position H5 as the toner is consumed by image formation. Until all the measurement areas are filled with the toner until the toner surface reaches the position H5, the electrostatic capacitance remains constant regardless of the remaining amount of toner. In this embodiment, the toner remaining amount is a section from 100% to 50%.

  Next, in FIG. 24B, in section 2 where the remaining amount of toner is from m2 to m3, the capacitance decreases as the remaining amount of toner decreases. The toner surface at this time is a position between H5 and H6 in FIG. During this time, the amount of toner changes in the measurement area 2, and therefore, the detection result in the measurement area 2 is dominant in the change in capacitance in the section 2. In the present embodiment, the toner remaining amount is a section from 50% to 30%.

  Next, in FIG. 24B, in section 3 where the remaining amount of toner is from m3 to m4, the capacitance is constant again regardless of the remaining amount of toner. The toner surface at this time is, for example, a position H7 in FIG. As long as there is toner in the non-measurement area, the amount of toner in that area cannot be measured, so the capacitance is constant regardless of the remaining amount of toner. In the present embodiment, the toner remaining amount is a section from 30% to 20%.

  While the toner surface is between H5 and H7, the vicinity of the developing sleeve 41 is almost filled with the toner sent by the stirring member 45, and the detection result in the measurement region 1 does not change much.

  Next, in FIG. 24B, in the section 4 where the remaining amount of toner is from m4 to 0%, the remaining amount of toner and the electrostatic capacity are in a linear relationship again. The toner surface at this time changes in the same manner as described in the third embodiment with reference to FIG. Specifically, the position is changed from H7 to H8 in FIG. During this time, the toner amount changes in the measurement region 1, and therefore, the detection result in the measurement region 1 is dominant in the change in the electrostatic capacitance in the section 4. In the present embodiment, the toner remaining amount is a section from 20% to 0%.

(Configuration of Comparative Example 6)
On the other hand, FIG. 25A is a schematic sectional view of the vicinity of the antenna member 43 of the developing device 4 in Comparative Example 6. Note that the configuration of Comparative Example 6 is substantially the same as that of the present embodiment except for the points specifically mentioned below. In Comparative Example 6, two antenna members, a first antenna member 43a and a second antenna member 43b, which are SUS metal plates are provided. The first and second antenna members 43a and 43b are disposed so as to face the developing sleeve 41, respectively. The first antenna member 43a is disposed in the vicinity of the developing sleeve 41 and the second antenna member 43b is disposed away from the developing sleeve 41 so that the remaining amount of toner in a wide range can be detected as compared with the comparative example 5 described above. Yes. In the first and second antenna members 43a and 43b, the closest point A to the developing sleeve 41 and the end B on the developing sleeve 41 side coincide with each other. The first and second antenna members 43a and 43b are connected to the same potential, and are connected to the ground through the capacitance measuring circuit 132.

(Evaluation of this embodiment and Comparative Example 6)
The present embodiment and Comparative Example 6 were evaluated in the same manner as in the third embodiment. The end B on the developing sleeve 41 side of the antenna member 43 of the present embodiment and comparative example 6 shown in FIGS. 24A and 25A is made smaller in the direction of arrow Z (the other end side) in the drawing. By doing so, the arrangement of the end B was changed by 2 mm. Then, the influence of the position accuracy on the detection accuracy of the toner remaining amount was evaluated. In Comparative Example 6, the arrangement of the end B on the developing sleeve 41 side in both the first and second antenna members 43a and 43b was changed by 2 mm as described above.

  FIG. 24C shows the relationship between the remaining amount of toner actually remaining in the developer container 46 and the detected capacitance in the configuration of this embodiment. FIG. 25B shows the relationship between the remaining amount of toner actually remaining in the developer container 46 and the detected capacitance in the configuration of Comparative Example 6. The solid lines in FIGS. 24C and 25B indicate the remaining amount of toner and the capacitance in the arrangement of the antenna member 43 of the present embodiment and the comparative example 6 shown in FIGS. 24A and 25A, respectively. Relationship. The broken lines indicate the relationship between the remaining amount of toner and the capacitance when the position on the end B side of the antenna member 43 is shifted by 2 mm as described above.

  24 (c) and 25 (b), it can be seen that the capacitance detected with respect to the actual toner remaining amount is small due to the effect of shifting the position of the end B of the antenna member 43. . Here, when the difference (change amount) ΔC between the solid line and the broken line is compared between the present embodiment shown in FIG. 24C and the comparative example 6 shown in FIG. 25B, the comparative example 6 is larger. The reason why ΔC is larger than that in the present embodiment in Comparative Example 6 is considered to be Reason 1, Reason 2, and Reason 3 described above.

Thus, in this embodiment, ΔC is smaller than that in Comparative Example 6. As a result, the difference between the amount of toner remaining when the electrostatic capacitance C ₀ is a timing white spot image occurs is detected, than ΔM5 in Comparative Example 6, towards ΔM4 in this embodiment is reduced.

  As described above, according to the present embodiment, the same effects as those of the third and fourth embodiments can be obtained, and without increasing the number of antenna members, etc. The remaining amount of toner can be sequentially notified from a state where the remaining amount of toner is large.

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 4 Developing apparatus 40 Developing frame body 41 Developing sleeve 43 Antenna member (conductive resin sheet)
46 developer container 100 image forming apparatus 110 apparatus main body 120 process cartridge

Claims (22)

A frame that forms a developer accommodating portion, a first electrode, and a second electrode that is formed integrally with the frame, the first electrode and the second electrode; In the method of manufacturing the frame body in which the second electrode used in the developing device that performs output according to the capacitance between the two is integrated ,
The money a second electrode and a conductive resin sheet holding step you positioned in a mold for molding the frame body to form a surface of the housing part side of the developer of the frame Bringing the surface of the conductive resin sheet into contact with the surface of the mold , and holding and positioning the first region of the conductive resin sheet in the holding region of the mold by a holding unit ;
Injecting resin for forming the frame into the mold holding the conductive resin sheet from a gate provided in the mold ;
Have a, and forming the frame member wherein the conductive resin sheet is fixed by curing the resin,
Regarding the short direction of the frame, the conductive resin sheet has one end and the other end, and the other end is located farther from the first region than the one end, and The other end portion is located downstream of the one end portion in the direction in which the resin injected from the gate spreads in the mold. The manufacturing method according to claim 1, wherein an injection direction of the resin in the gate is a thickness direction of the frame body. The thickness of the said conductive resin sheet is 0.05 mm or more and 0.3 mm or less, The manufacturing method of Claim 1 or 2 characterized by the above-mentioned. The portion of the conductive resin sheet extending from the first region excluding the first region to the other end corresponds to a second region, and the conductive resin sheet in the second region includes the holding region. The manufacturing method according to any one of claims 1 to 3, wherein the manufacturing method is not held by the holding means. The manufacturing method according to claim 4, wherein a length of the first region in a short direction of the frame is shorter than a length of the second region. A frame that forms a developer accommodating portion, a first electrode, and a second electrode that is formed integrally with the frame, the first electrode and the second electrode; In the method of manufacturing the frame body in which the second electrode used in the developing device that performs output according to the capacitance between the two is integrated,
  The mold for forming and forming a surface of the frame on the developer accommodating portion side, which is a step of holding and positioning a conductive resin sheet as the second electrode on a mold for molding the frame. A step of bringing the surface of the conductive resin sheet into contact with the surface of the mold and holding and positioning the conductive resin sheet in a holding region of the mold by holding means;
  Injecting resin for forming the frame into the mold holding the conductive resin sheet from a gate provided in the mold;
  Curing the resin to form the frame to which the conductive resin sheet is fixed, and
  The holding means holds a region on one end side in the short direction of the frame body of the conductive resin sheet in the holding region, and the other end side in the short direction facing the one end side is the holding region. The method of manufacturing the frame body, wherein the frame body is not held and is further away from the gate than the one end side in the lateral direction. The manufacturing method according to claim 6, wherein an injection direction of the resin in the gate is a thickness direction of the frame body. The manufacturing method according to claim 6 or 7, wherein the thickness of the conductive resin sheet is 0.05 mm or more and 0.3 mm or less. The portion of the conductive resin sheet that extends from the first region to the other end, excluding the first region held in the holding region of the conductive resin sheet, corresponds to the second region, and the frame body is short. The manufacturing method according to claim 6, wherein a length of the first region in the hand direction is shorter than a length of the second region. A frame that forms a developer accommodating portion, a first electrode, and a second electrode that is formed integrally with the frame, the first electrode and the second electrode; In the method of manufacturing the frame body in which the second electrode used in the developing device that performs output according to the capacitance between the two is integrated,
  The mold for forming and forming a surface of the frame on the developer accommodating portion side, which is a step of holding and positioning a conductive resin sheet as the second electrode on a mold for molding the frame. A surface of the conductive resin sheet is brought into contact with the surface of the conductive resin sheet, and a first region of the conductive resin sheet is held and positioned in a holding region of the mold by a holding unit;
  Injecting resin for forming the frame into the mold holding the conductive resin sheet from a gate provided in the mold;
  Curing the resin to form the frame to which the conductive resin sheet is fixed, and
  Regarding the short direction of the frame, the conductive resin sheet has one end and the other end, and the other end is located farther from the first region than the one end, and The other end portion is further away from the gate than the first region. The manufacturing method according to claim 10, wherein an injection direction of the resin in the gate is a thickness direction of the frame body. The thickness of the said conductive resin sheet is 0.05 mm or more and 0.3 mm or less, The manufacturing method of Claim 10 or 11 characterized by the above-mentioned. The portion of the conductive resin sheet extending from the first region excluding the first region to the other end corresponds to a second region, and the conductive resin sheet in the second region includes the holding region. It is not hold | maintained by the said holding means via the manufacturing method of any one of Claims 10 thru | or 12 characterized by the above-mentioned. The length of the said 1st area | region in the transversal direction of the said frame is shorter than the length of the said 2nd area | region, The manufacturing method of Claim 13 characterized by the above-mentioned. The conductive resin sheet is in the frame side, to any one of claims 1 to 14, characterized in that it has the frame body resin compatible or have been surface composed of a material having adhesive properties to form a manufacturing method described. 16. At least one part of the surface which contacts the said metal mold | die of the said conductive resin sheet becomes a surface of the said 2nd electrode facing the said 1st electrode, The any one of Claim 1 thru | or 15 characterized by the above-mentioned. manufacturing method according to. The conductive resin sheet surface opposite to the side where the surface facing the first electrode, according to claim 15 or 16, characterized in that it has a resin compatible or adhesive to form the frame body manufacturing method according to. The entire surface of the conductive resin sheet the frame side of, manufacturing method of any one of claims 15 to 17, wherein a resin compatible or adhesive to form the frame body. Step you positioning pre Kiho lifting is any one of claims 1 to 18, characterized in that it comprises holding said conductive resin sheet by air suction through holes provided in the mold manufacturing method according to. Manufacturing method according to any one of claims 1 to 19, characterized in that the surface for holding the conductive resin sheet of the mold is curved. The conductive resin sheet is manufacturing method according to any one of claims 1 to 20, characterized in that it has a single layer structure or a multilayer structure. Before Kichu step of entering the manufacturing method according to any one of claims 1 to 21, characterized in that it comprises injecting a resin from a direction intersecting the longitudinal direction of the conductive resin sheet.

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