JP2002268363A - Developing device, process cartridge and electrophotographic imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device, a process cartridge and an electrophotographic imaging device, by which the residual amount of developer is accurately and successively detected. SOLUTION: In this developing device, which possesses a developing member 4a and several electrodes arranged nearly in parallel in the longitudinal direction of the developing member 4a; at least two electrodes 31 and 32 from among a plurality of electrodes are arranged on the two side faces of a recessed part 30, having an aperture on a lower side in the state that the developing device 4 is attached to the electrophotographic imaging device 100; voltage is applied to at least either one of the electrodes 31 and 32 arranged on the two side faces of the recessed part 30 for detecting the residual amount of the developer in the electrophotographic imaging forming device, and an electrical signal, corresponding to an electrostatic capacity between the electrodes 31 and 32, arranged at least on the two side faces of the recessed part is generated; and the detection sensitivity of the residual amount of the developer at the upper part 30a of the recessed part 30 is made low.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to an electrophotographic system in which an electrostatic latent image is formed on an image carrier by an electrophotographic method, and the electrostatic latent image is visualized by a developer contained in a developing device. The present invention relates to a photographic image forming device, a developing device, and a process cartridge.

Here, as an electrophotographic image forming apparatus, for example, an electrophotographic copying machine, an electrophotographic printer (for example, L
ED printers, laser beam printers, etc.), and electrophotographic facsimile machines.

[0003] A process cartridge is a cartridge in which at least one of a charging means, a developing means and a cleaning means as a process means acting on an electrophotographic photosensitive member and an electrophotographic photosensitive member are integrally formed into a cartridge. The cartridge may be detachable from the main body of the photographic image forming apparatus, or at least the developing means and the electrophotographic photosensitive member may be integrally formed into a cartridge, and the cartridge may be detachable from the main body of the electrophotographic image forming apparatus. To do.

[0004]

2. Description of the Related Art For example, an electrophotographic image forming apparatus such as a copying machine or a laser beam printer irradiates a uniformly charged electrophotographic photosensitive member (photosensitive member) with light corresponding to image information to form an electrostatic latent image. An image is formed, a developer (toner) as a recording material is supplied to the electrostatic latent image by a developing unit to visualize it as a toner image, and the toner image is further transferred from a photoconductor to a recording paper or the like, Thereafter, the image is fixed on the recording medium by heat and pressure to form an image on the recording medium. A developer accommodating section (developer container) accommodating a developer is connected to the developing means, and the developer is consumed by forming an image.

[0005] In many cases, the developer accommodating section, the developing means, the photoreceptor, the charging means, and the like are integrally formed as a cartridge to form a process cartridge that can be attached to and detached from the apparatus body. In this case, normally, when the developer runs out, the user can replace the process cartridge to form an image again. According to this process cartridge system,
Since the maintenance of the apparatus can be performed by the user himself without relying on a service person, the operability can be remarkably improved. Therefore, this process cartridge system is widely used in image forming apparatuses.

[0006] Further, there is a developing device provided with a developing means and a developer accommodating portion connected to the developing device as a unit to form a cartridge (developing cartridge) detachable from the main body of the device.

In recent years, in order to know at any time how much developer that can be used for image formation remains in a cartridge (process cartridge, developing cartridge), the remaining amount of developer that can detect the level of remaining developer can be detected. There has been proposed an apparatus in which a detection unit is provided in a cartridge or an image forming apparatus main body.

As one of the developer remaining amount detecting means, there is a detecting method using a plate electrode. In this method, at least one flat electrode (plate electrode) facing a roller-shaped developing member (developing roller) as a developing means is provided, and between the developing roller and the plate electrode, or a plurality of electrodes are provided. The space between the plate electrodes is used as a capacitor electrode. Then, the developer remaining level is detected by utilizing the fact that the capacitance between the electrodes changes according to the amount of the insulating developer.

That is, if the space between the condenser constituted by the plate electrode and the developing roller is filled with the developer, the capacitance increases, and as the developer decreases, the air increases in the space and the capacitance decreases. It is becoming. Accordingly, by preparing a correction table in which the relationship between the capacitance between the plate electrode and the developing roller and the amount of developer is prepared in advance, it is possible to detect the level of the remaining amount of developer in the developer accommodating portion.

In particular, the correction table is based on a detection value when the capacitance is the maximum, that is, when the amount of the developer between the electrodes is the maximum. Using a correction table in which the remaining level is related in advance,
The detected value of the capacitance can be converted to the remaining amount of the developer. The maximum value of the capacitance is always compared with the current maximum value and the detected value of the capacitance. If a larger capacitance is detected, the capacitance is rewritten as the maximum value. Thus, based on the constantly updated maximum value of the capacitance, the amount of change from this value can be converted to the remaining amount of the developer.

When the capacitance detected between the electrodes reaches a predetermined value, a warning of "no toner" is issued, and if the image forming apparatus is of a detachable cartridge type, the replacement is urged.

Conventionally, as shown in FIG. 17, a plate electrode has a configuration in which an opening is directed downward at a concave portion 30 in a developing chamber 41 for supporting a developing member. That is, the electrodes 131 and 132 are arranged on the left and right side surfaces of the concave portion 30 in the drawing. Then, based on the capacitance change between the electrodes, the remaining amount of the developer is calculated as described above. In particular, conventionally, the electrodes 13 arranged on the left and right side surfaces of the concave portion 30 are conventionally used.
Reference numerals 1 and 132 extend their upper ends 131a and 132a to the uppermost surface 30a of the concave portion 30, and try to detect the amount of developer entering the concave portion 30 to the maximum.

In order to more accurately detect the remaining amount of the developer using the remaining amount of developer detecting means, for example, in the case where a plurality of cartridges are exchanged and used for the main assembly of the apparatus, each cartridge is provided separately. It has been proposed to provide readable and writable storage means (memory). This storage means stores, for example, (1) developer remaining amount value information (for example, remaining amount 24
%, Remaining amount 20%), and (2) history information indicating that the developer amount is equal to or less than a predetermined value (for example, “Toner-Low” meaning to prompt the preparation of a new cartridge shortly before the developer runs out. A signal or information indicating whether or not a “Toner-Out” signal has been warned immediately, which means that a new cartridge needs to be prepared immediately before the developer runs out) is stored for each cartridge. is there.

[0014]

However, conventionally,
Since the amount of the developer that enters the concave portion 30 due to the plate electrodes 131 and 132 is unstable, the capacitance is changed to a predetermined amount after the capacitance at which the amount of the developer is maximum or the maximum capacitance is determined. May reach. As a result, an erroneous detection of a change in the remaining amount of the developer may occur even though the amount of the developer has hardly decreased.

Accordingly, it is an object of the present invention to provide a developing device, a process cartridge, and an electrophotographic image forming apparatus capable of sequentially detecting the remaining amount of developer with high accuracy.

Another object of the present invention is to prevent erroneous detection of the remaining amount of the developer due to a change in capacitance between the electrodes even when the developer remains sufficiently. It is an object of the present invention to provide a developing device, a process cartridge, and an electrophotographic image forming apparatus which can be used.

[0017]

The above object is achieved by a developing device, a process cartridge and an electrophotographic image forming apparatus according to the present invention. In summary, a first aspect of the present invention is a developing apparatus for developing an electrostatic latent image formed on an electrophotographic photosensitive member, which is used in an electrophotographic image forming apparatus,
A developing member for supplying a developer to the electrophotographic photosensitive member for developing an electrostatic latent image formed on the electrophotographic photosensitive member; and a plurality of developing members arranged substantially in parallel along a longitudinal direction of the developing member. And at least two electrodes of the plurality of electrodes are two side surfaces of a concave portion having an opening below when the developing device is mounted on the electrophotographic image forming apparatus. In order to detect the remaining amount of the developer in the electrophotographic image forming apparatus, a voltage is applied to at least one of the electrodes disposed on the two side surfaces of the concave portion, at least the What is claimed is: 1. A developing device for generating an electric signal according to a capacitance between electrodes disposed on two side surfaces of a concave portion, wherein a detection sensitivity of a remaining amount of the developer in an upper portion of the concave portion is reduced. Is a developing device.

According to a second aspect of the present invention, there is provided a process cartridge detachable from an electrophotographic image forming apparatus main body.
(A) an electrophotographic photosensitive member, (b) a developing member for supplying a developer to the electrophotographic photosensitive member for developing an electrostatic latent image formed on the electrophotographic photosensitive member, and A plurality of electrodes arranged substantially in parallel along the longitudinal direction, and at least two of the plurality of electrodes, in a state where the process cartridge is mounted on the electrophotographic image forming apparatus main body, It is arranged on two side surfaces of a concave portion having an opening below, and is arranged on two side surfaces of the concave portion in order to detect the remaining amount of developer in the electrophotographic image forming apparatus main body. A voltage is applied to at least one of the electrodes, and the developing device generates an electric signal corresponding to a capacitance between electrodes disposed on at least two side surfaces of the concave portion. Sense of detection of developer remaining in upper part Process cartridge is provided which is characterized in that it has a, a developing device blunted.

According to a third aspect of the present invention, there is provided an electrophotographic image forming apparatus for forming an image on a recording medium, wherein (a)
An electrophotographic photosensitive member; (b) an electrostatic latent image forming means for forming an electrostatic latent image on the electrophotographic photosensitive member; and (c) developing the electrostatic latent image formed on the electrophotographic photosensitive member. To do
A developing member for supplying a developer to the electrophotographic photoreceptor; and a plurality of electrodes arranged substantially in parallel along a longitudinal direction of the developing member.
One of the two electrodes has a concave portion 2 having an opening at the bottom when the developing device is mounted on the electrophotographic image forming apparatus.
A developing device arranged on two side surfaces, wherein the developing device has a reduced sensitivity for detecting the remaining amount of the developer in the upper portion of the concave portion; and (d) the developing device is disposed on two side surfaces of the concave portion. Developing by applying a voltage to at least one of the electrodes to generate an electric signal corresponding to a capacitance between at least two electrodes arranged on two side surfaces of the concave portion, and measuring the electric signal. An electrophotographic image forming apparatus, comprising: means for detecting the remaining amount of the agent.

According to a fourth aspect of the present invention, there is provided an electrophotographic image forming apparatus for forming an image on a recording medium in which a process cartridge is detachable, wherein (a) an electrophotographic photosensitive member; A developing member for supplying a developer to the electrophotographic photoreceptor for developing the formed electrostatic latent image; and a plurality of electrodes arranged substantially parallel along a longitudinal direction of the developing member. At least two of the plurality of electrodes are arranged on two side surfaces of a concave portion having an opening below when the process cartridge is mounted on the electrophotographic image forming apparatus main body. Mounting means for removably mounting a process cartridge comprising: a developing device, the developing device having a reduced sensitivity of detecting a remaining amount of a developer in an upper portion of the concave portion; and (b) the electronic device. An electrostatic latent image forming means for forming an electrostatic latent image on the true photoreceptor; and (c) applying a voltage to at least one of electrodes arranged on two side surfaces of the concave portion, Means for generating an electric signal in accordance with the capacitance between the electrodes arranged on the two side surfaces of the concave portion, and detecting the remaining amount of the developer by measuring the electric signal. An electrophotographic image forming apparatus is provided.

According to one embodiment of the present invention, at least one of the electrodes arranged on the two side surfaces of the concave portion serves as means for lowering the detection sensitivity of the remaining amount of the developer in the upper portion of the concave portion. The upper end of one electrode is lower than the uppermost part of the concave portion.

According to another embodiment of the present invention, the means for lowering the detection sensitivity of the remaining amount of the developer in the upper portion of the concave portion is provided between electrodes arranged on two side surfaces of the concave portion. A regulating member that regulates the entry of the developer into the upper part is arranged. Then, the regulation member can completely prevent the developer from entering at least one upper end of the electrodes arranged on the two side surfaces of the concave portion.
Further, as the regulating member, a member other than a conductive member can be suitably used.

According to another embodiment of the present invention, a first electrode and a second electrode closer to the developing member are arranged on two side surfaces of the concave portion, respectively.
A voltage is applied to the developing member and the second electrode, between the developing member and the first electrode, and between the first electrode and the second electrode via the first electrode. And generates an electric signal corresponding to the capacitance between them. Further, the first electrode and the second electrode can be plate-shaped.

Further, the process cartridge may further have at least one of a charging unit for charging the electrophotographic photosensitive member and a cleaning unit for cleaning the electrophotographic photosensitive member.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a developing device, a process cartridge and an electrophotographic image forming apparatus according to the present invention will be described in more detail with reference to the drawings.

Embodiment 1 First, referring to FIG. 1 and FIG. 2, the overall configuration and operation of an embodiment of an electrophotographic image forming apparatus according to the present invention will be described.

In the present embodiment, the electrophotographic image forming apparatus
The laser beam printer (printer) 100 receives image information from a host computer and outputs an image to a recording medium such as a recording sheet, an OHP sheet, or a cloth.

The printer 100 has a cylindrical electrophotographic photosensitive member (photosensitive drum) 1 as an image carrier. At the time of image formation, the photosensitive drum 1 is uniformly charged by a roller-shaped charging member (charging roller) 2 as charging means. Above the photosensitive drum 1, a laser scanner 3 for irradiating a laser beam L corresponding to image information is provided as exposure means. The uniformly charged surface of the photosensitive drum 1 is scanned and exposed by the laser beam L emitted from the laser scanner 3 to form an electrostatic latent image of target image information. Next, a developer (toner) T is attached to the electrostatic latent image formed on the photosensitive drum 1 by the operation of the developing device 4 and is visualized as a toner image.

That is, as can be understood by referring to FIG. 2, in the present embodiment, the developing device 4 is a roller-shaped developing member (developer carrying member) disposed opposite to the photosensitive drum 1 as developing means. That is, it has a developing chamber 41 that supports the developing roller 4a, and a developer accommodating section (developer container) 42 connected to the developing chamber 41. In the present embodiment, the developer container 42 contains an insulating magnetic one-component toner as the developer T, and the developer in the developer container 42 is rotated by the developer stirring / conveying member 4d rotating in the direction of the arrow. T is stirred and transported to the developing chamber 41. In the developing chamber 41,
A developer stirring member 4e is provided near the developing roller 4a, and thereby circulates the developer T in the developing chamber 41. The developing roller 4a incorporates a fixed magnet (magnet roll) 4b, and the developer T is transported by rotating the developing roller 4a. Also, the developing roller 4a
An elastic blade-shaped developer regulating member (developing blade) 4c for regulating the layer thickness of the developer T in contact with the developing roller 4a is provided. The agent T is given a triboelectric charge. The developer T supplied to the developing area of the photosensitive drum 1 is transferred to a latent image formed on the photosensitive drum 1 to form a toner image. The developing roller 4a is connected to a developing bias circuit, and is usually applied with a developing bias in which a DC voltage is superimposed on an AC voltage.

On the other hand, a recording medium P such as recording paper is stacked in a recording medium storage cassette 8 which is a recording medium storage section. The recording medium P includes a pickup roller 9a.
Is picked up one by one by the transport roller 9b.
To the registration roller pair 9c. The recording medium P is further conveyed to the transfer section in synchronization with the toner image on the photosensitive drum 1 by the registration roller pair 9c. Then, the toner image on the photosensitive drum 1 is transferred to the recording medium P by the action of a roller-shaped transfer member (transfer roller) 5 as a transfer unit in the transfer section.

The recording medium P to which the toner image has been transferred is conveyed to the fixing device 7. The fixing device 7 includes a fixing roller 5a having a built-in heater and a driving roller 7b. The unfixed toner image on the recording medium P is melted by heat and pressure and fixed on the recording medium P. Thereafter, the recording medium P is conveyed by discharge rollers 9e, 9f and the like, and is discharged to a tray 10 provided at the upper part of the apparatus in this embodiment.

After the transfer of the toner image onto the recording medium P, the photosensitive drum 1 is cleaned by the cleaning device 6 such as the developer T remaining without being transferred. The cleaning device 6 scrapes off the residual developer T from the photosensitive drum 1 by an elastic blade-shaped cleaning member (cleaning blade) 7a that comes into contact with the photosensitive drum 1 as cleaning means, and stores the residual developer T in a waste developer container 7b.

As shown in FIG. 2, in this embodiment, the photosensitive drum 1, the charging roller 2, the developing device 4, and the cleaning device 6 are integrally formed, and the electrophotographic image forming apparatus main body A Process cartridge B detachable from
It has been. The process cartridge B is a developing unit (developing device configuration) in which a developer frame 42a forming a developer container 42 and a developing frame (developing frame) 41a forming a developing chamber 41 are welded and integrated into a unit. And a cleaning frame 11 to which the photosensitive drum 1, the charging roller 2 and the cleaning device 6 are attached.

The process cartridge B is detachably mounted on the apparatus main body A via the mounting means 12 provided on the apparatus main body A. Then, usually, when the developer T is exhausted, the user attaches / detaches the process cartridge to / from the apparatus main assembly A and replaces it. Thereby, together with the replenishment of the developer T,
Consumables such as the photosensitive drum 1 can be replaced by the user himself.

In this embodiment, before the process cartridge B is used, the developer sealing member 13 is attached between the developer container 42 and the developing chamber 41. The developer sealing member 13 is provided so that the developer T does not leak even when a strong impact occurs during transportation of the process cartridge B or the like. The developer sealing member 13 is opened by the user immediately before the process cartridge B is mounted on the apparatus main assembly A. Incidentally, the configuration may be such that the developer sealing member 13 is automatically removed after being mounted on the apparatus main body A.

Next, a description will be given of a developer amount detecting device provided in the printer 100 of this embodiment.

The printer 100 of this embodiment is provided with a developer amount detecting device capable of sequentially detecting the remaining amount as the developer T in the developer container 42 is consumed. In the present embodiment, the developer amount detecting device can convert the measured value of the developer remaining amount detecting unit, which is a sensor unit, to a developer remaining amount by comparing the measured value of the developer remaining amount detecting unit with a reference value. And a remaining amount detection and detection unit serving as a signal.

In this embodiment, the developer remaining amount detecting means measures the capacitance using the developing roller 4a as an electrode and the first and second plate electrodes 31 and 32 which are plate-like electrode members. System.

As is well understood with reference to FIGS. 3 and 4, the first plate electrode 31 and the second plate electrode 32 can contain the developer T sent by the developer stirring / conveying member 9d. Such a concave portion 30 having an open lower portion is formed. These first plate electrodes 3
The first and second plate electrodes 32 are spaced apart substantially in parallel with the longitudinal direction of the developing roller 4a at positions substantially facing the developing roller 4a. That is, the first and second plate electrodes 31 and 32 are arranged in a direction intersecting with the moving direction of the developer T moved by the developer stirring / stirring / transporting member 4d, for example, as shown in FIG. Then the developing room 41
Is attached to the frame body 41a constituting

In this embodiment, by applying an AC voltage to the developing roller 4a and the second plate electrode 32, the first plate electrode 31 is moved between the developing roller 4a and the first plate electrode 31. And the second plate electrode 32
The amount of developer is detected by measuring the capacitance between the two.

That is, since the dielectric constant of the developer T is higher than that of air, the developer T is developed between the developing roller 4a and the first plate electrode 31 and between the first plate electrode 31 and the second plate electrode 32. The capacitance increases when the agent T is present.
Therefore, when the developer T is sufficient in the developing chamber 41, the developer T is supplied between the developing roller 4 a and the first plate electrode 31 and between the first plate electrode 31 and the second plate electrode 32. Since the developer T sufficiently enters the gap, a large capacitance is always output. Then, as the developer T in the developing chamber 41 is consumed, the first plate electrode 3 gradually increases.
The amount of the developer T entering between the first and second plate electrodes 32 and further between the developing roller 4a and the first plate electrode 31 decreases, and the capacitance also decreases. Thus, the developer amount detecting device can sequentially detect the amount of the developer by detecting the change in the capacitance.

The first and second plate electrodes 31 and 32 are
Basically, any material capable of passing a current can be used without any particular limitation. In this embodiment, rust-resistant SUS is used as a material.

The first and second plate electrodes 31, 3
The more detailed configuration 2 will be described later.

Referring to FIG. 5, a description will be given of a developer remaining amount detecting circuit of the developer amount detecting device of the present embodiment. FIG. 5 shows a circuit configuration of the developer amount detecting device when the process cartridge B is normally mounted on the apparatus main body A. The apparatus main body A and the process cartridge B are provided with electrical contacts (not shown), respectively. When the process cartridge B is mounted in the apparatus main body A, the electric contacts are provided on the process cartridge B through the electric contacts. First and second plate electrodes 31 and 32 and remaining amount detection and detection unit 26 in apparatus body A
Are electrically connected.

More specifically, as shown in FIG. 5, when the process cartridge B is mounted on the main assembly A of the apparatus, the process cartridge B and the main assembly A are electrically connected to each other through electrical contacts. A developing bias circuit 34 is connected to the developing roller 4a and the second plate electrode 32. Further, the developing bias circuit 34 is connected to the reference capacitor 35 of the remaining amount detection detector 26. The developing bias circuit 34 outputs a predetermined developing bias (AC bias), and the applied bias is applied to the reference capacitor 35 having a fixed capacitance, the developing roller 4 a in the developing device 4, This is applied to the plate electrode 32, respectively.

The comparison detection circuit 36 of the developer remaining amount detection detection section 26 is connected to the first plate electrode 31 via the reference capacitor 35 and the contacts provided on the process cartridge B and the apparatus main assembly A, respectively. . Then, the comparison detection circuit 36 determines whether the reference value (voltage V1) generated at both ends of the reference capacitor 35 (capacitance C1: fixed value) is between the first plate electrode 31 and the second plate electrode 32. (C3: variable depending on the remaining amount of developer) and the combined capacitance (C2 = variable depending on the remaining amount of developer) between the developing roller 4a and the first plate electrode 32 (C4 = C2 + C3) A voltage V3 is generated from a voltage difference from a measured value (voltage V2) generated with respect to. This voltage V3 is output to the calculation unit (AD conversion unit) 24. The arithmetic unit 24 converts the analog voltage V3 into digital data, and sends the result to the control unit 23. Then, the controller 23 determines the remaining amount level of the developer by using the remaining amount detection correction table 25 (FIG. 6) set in advance by obtaining the relationship between the voltage V3 and the remaining amount of the developer.

In this embodiment, an AC bias of about 2 kHz as a developing bias and -400
A bias in which a DC bias of about V is superimposed is used.

As described above, in this embodiment, the developing roller 4a and the first and second plate electrodes 31, 32 relatively close to the developing roller 4a are used as the developer remaining amount detecting means. From this positional relationship, in the present embodiment, from the point in time when the developer T in the developing device 4 has been consumed to approximately half (100 g in this embodiment) or less, the electrostatic capacity detected by the developer remaining amount detecting means decreases. Begins. In the present embodiment, since the capacitance and the detection voltage have the inverse increase / decrease relationship due to the configuration of the detection circuit, the detection voltage (V3 in FIG. 5) starts increasing at this point as shown in FIG. After that, until the developer T runs out, strictly speaking, the developer T decreases to a certain degree that there is a possibility of occurrence of a blank image, and the remaining amount of the developer T is sequentially detected until a warning of “no toner” is issued. it can. Usually, the remaining amount of the developer in the range until the developer T decreases to about 20 g can be sequentially detected.

More specifically, in the remaining amount detection system of this embodiment, first, the first and second plate electrodes 3
The capacitance (detected voltage value V3) is detected in accordance with the amount of the developer T that has entered the first and second developer 32. In order to take the maximum of the detected value of the capacitance (the minimum value of the detected voltage value V3), the detected value is always compared with the currently stored maximum value, and if the new detected value is larger, the data is sequentially rewritten.

When the detected value of the capacitance decreases at a certain point in time, the detected value is converted into the remaining amount of the developer by using the prepared remaining amount detection correction table 25. That is, for example,
When the amount of change from the maximum capacitance is 0.3 V, the remaining amount of the developer is 25%, and when the amount of change is 0.4 V, it is 20%. Are converted into the remaining amount of the developer by the remaining amount detection correction table 25 in which. Then, when the amount of change in the capacitance becomes equal to or more than a predetermined value, a warning such as “no toner” is issued.

The method of displaying the remaining amount of the developer will be described.
For example, as shown in FIG. 14, the detection information obtained by the above-described developer amount detection device directly indicates the remaining amount of the developer on the terminal screen 51 of the user's personal computer 50 or the like by a numerical value (for example, “toner remaining amount 10%”). 15 (a) and FIG.
It can be displayed as shown in FIG. FIG.
15A and 15B, the user is notified of the amount of developer based on which part of the gauge 62 the needle 61 that moves according to the amount of developer is pointing. Also, as shown in FIGS. 6 and 16, the electrophotographic image forming apparatus main body is directly
A display unit 28 such as an LED may be provided, and the LED may be blinked according to the amount of the developer.

It should be noted that detecting the developer T sequentially means that when the amount of the developer T stored in the container is initially set to 100%, the remaining amount of the developer T is about 100% to 0%. The detection is not limited to the entire area up to the above, and may be performed sequentially over the area where the remaining amount of the developer T in the container is from 50% to 0%. here,
The fact that the remaining amount of the developer T is 0% does not only mean that the developer T has completely disappeared. For example, the developer T
The remaining amount of 0% includes that the remaining amount of the developer T is reduced to such an extent that a predetermined image quality (development quality) cannot be obtained even if the developer T remains in the container.

Next, the storage means (memory) 20 mounted on the cartridge C will be described. 1 and 2
As shown in FIG.
A storage unit 20 is provided at one side (tip) of the waste developer container 6b.
And a cartridge-side transmission unit (communication unit) 21 for controlling reading and writing of information from and to the storage unit 20. When the process cartridge B is mounted on the apparatus main assembly A, the cartridge side transmission section 21 and the main body control section 22 are arranged to face each other. In the present embodiment, the main body control unit 22
Has a function of a transmission unit (communication means) on the main body side.

As described above, in this embodiment, the storage unit 20
Is disposed on the waste developer container 6a side. This is because the process cartridge B is inserted into the apparatus main body A with the waste developer container 6a side at the head, so that the storage unit 20 and the communication unit on the apparatus main body A side are easily aligned. .

As the storage means 20, a nonvolatile memory,
An ordinary semiconductor electronic memory such as a combination of a volatile memory and a backup battery can be used without any particular limitation. In particular, in the case of a non-contact memory in which data communication between the memory and the read / write IC is performed by electromagnetic waves, the contact between the cartridge-side transmission unit 21 and the main body control unit 22 is non-contact. There is no possibility of poor contact, and highly reliable control can be performed. In this embodiment, a non-contact type memory is used as the storage unit 20.

Referring to FIG. 6, memory 2 in the present embodiment
The control configuration of 0 will be described. On the process cartridge B side, a memory 20 and a cartridge-side transmission unit 21 are arranged. Further, a main body control unit 22 is disposed in the apparatus main body A, and the main body control unit 22 includes a control unit 23 and a calculation unit 2.
4, a remaining amount detection correction table (remaining amount detection correction table storage unit) 25, a remaining amount detection detection unit 26, a main body side storage unit (memory) 27, and the like. The main body control unit 22 constitutes control means for reading and writing information in the memory 20 provided in the process cartridge B.

The information written in the memory 20 of the process cartridge B is sent to the main unit side memory 27 when the use of the process cartridge B is started. Then, at the time of image formation, the remaining amount of the developer and whether the amount of the developer is equal to or less than a predetermined value is calculated by the above-described method, and the display is updated as necessary. That is, the main body control unit 22 transmits a signal for displaying the remaining amount of the developer T or a warning to the display unit 28 or an external device 50 such as a personal computer communicably connected to the apparatus main body A. These values are stored in the main unit side memory 27 as needed every time the calculation is performed. For example, when the image formation is completed and the operation of the printer 100 is stopped, the values are sent to the memory 20 of the process cartridge B and stored. Let it.

In the printer 100 of this embodiment, if it is considered that the process cartridges B have been replaced due to the assumption that a plurality of process cartridges B are used (for example, the apparatus main assembly A). The door 14 of the apparatus main assembly A (FIG. 1) is used when the power supply is turned on or when the process cartridge B is inserted or removed.
Is closed), the contents of the main body side memory 27 are all reset.

Next, the arrangement of the developer remaining amount detecting means in this embodiment will be described in more detail.

FIG. 8 shows the first and second plate electrodes 31,
32 is shown enlarged. On the other hand, FIG. 17 shows an example of the concave portion 30 using the conventional plate electrodes 131 and 132.

Conventionally, as shown in FIG. 17, in the first and second plate electrodes 131 and 132 arranged in the concave portion 30 having the opening below, the plate area of both electrodes 131 and 132 is maximized. To increase the capacitance between both electrodes, thereby increasing the amount of change in the capacitance, and trying to accurately detect the remaining amount of the developer. For this purpose, the upper end portion 131 of the first and second plate electrodes 131 and 132 extends to the uppermost surface portion 30a of the concave portion 30.
a, 132a were high.

However, as a result of intensive studies by the present inventors, it has been found that such a configuration causes a false detection.

That is, because the intrusion of the developer T into the concave portion 30 is unstable, the capacitance between the first and second plate electrodes 131 and 132 becomes unstable. . The reason why the intrusion of the developer T into the concave portion 30 becomes unstable may be as follows.

That is, the developer T enters upward against gravity. Therefore, the flow of the developer T includes the developing chamber 41.
The force of the developer T circulating in the developing chamber 41 due to the weight of the developer T therein, the force of the developer stirring / conveying member 4d, and the rotation of the developing roller 4a and the developer stirring member 4e, etc. I have. The force for pushing the developer T into the concave portion 30 varies. Therefore, as shown in FIG. 17, the upper surface S of the developer T in the concave portion 30 moves up and down to some extent as indicated by the arrow in the figure (hatched portion).

In the state where the image forming operation is stopped, almost no force is applied to push up the developer T, and the developer T tends to move downward by gravity. Therefore, the upper surface S of the developer T in the concave portion 30 is greatly reduced.

For example, as described above, in the present embodiment, the amount of developer is detected by using the remaining amount detection correction table 25 from the amount of change from the maximum value of the capacitance (the minimum value of the detection voltage value V3). (For example, if the variation is 0.3 V, the remaining amount of the developer is 25%, and if the variation is 0.4 V, the remaining amount of the developer is 20%).

Accordingly, in this case, during the use of the process cartridge B, the unstable upper surface S of the developer is lowered between the first and second plate electrodes 31 and 32 in the concave portion 30, and the detected voltage value is lowered. If the change amount is 0.3 V, it is erroneously detected that the remaining amount of the developer is 25% even though the developer T is sufficient, and a warning or display is made to that effect.

In order to prevent this erroneous detection, the present inventors paid attention to the behavior of the developer T in the concave portion 30. In other words, the sensitivity of the developer amount detecting means in the portion corresponding to the amount of the developer which is vertically unstable in the concave portion 30 (developer upper surface S) is reduced, and the detection accuracy is improved by not detecting the portion. I found what I could do.

In this embodiment, as shown in FIG. 8, the first and second plate electrodes 31 and 32 disposed on the concave portion 30 are formed.
The upper end portions 31a and 32a of the
a. That is, erroneous detection is prevented by setting the upper end portions 31a and 32a of the first and second plate electrodes lower than the uppermost surface 30a of the concave portion 30. In FIG. 8, the upper surface S of the developer that moves up and down in the concave portion 30 is indicated by hatched portions.

More specifically, as will be understood with reference to FIG. 4, in this experimental example, the first plate electrode 31
Is thickness (t1) 0.3 mm, width (height) (W1) 1
1.6 mm and length (L1) 210 mm. Also, the first
Of the plate electrode 31 is bent at a substantially right angle along the longitudinal direction toward the downstream side in the developer conveying direction so as to be closer to the developing roller 4a.
1b. The length (11) of the bent portion 31b was 1.6 mm. Then, with respect to the first plate electrode 31, the cut width w from the uppermost surface 30a of the concave portion 30 is obtained.
1 was 9 mm.

On the other hand, the second plate electrode 32 has a thickness (t2) of 0.5 mm, a width (W2) of 4.9 mm, and a length of 21 mm.
0 (L2) mm. Then, the second plate electrode 3
With respect to 2, the cut width w2 from the uppermost surface 30a of the concave portion 30 was 9 mm.

In the concave portion 30, the upper ends 31a and 32a of the first and second electrodes 31 and 32 have a height at which the developer upper surface S may be lowered even when the developer T is sufficient. 8 (in the vicinity of the lower boundary in the moving direction of the developer upper surface S indicated by the hatched portion in the middle).

Alternatively, in a state where the developer T is sufficient, if the developer upper surface S is temporarily
Even when the upper and lower portions 1 and 32 become lower than the upper end portions 31a and 32a, the amount of change in the capacitance (detected voltage value V3) is the amount of change that can warn the remaining amount, that is, the amount of developer. First and second so that the amount does not reach the amount recognized as
The upper ends of the plate electrodes 31 and 32 may be made lower.

The first and second plate electrodes 31, 3
2, the height of the upper end portions 31a, 32a, ie, the cut width w
1 and w2 are variable depending on the configuration of the developing device 4 and the process cartridge B, or the meaning width of the display of the remaining amount of the developer in the remaining amount detection correction table 25, and the present invention is not limited to a specific value. .

As described above, according to the present embodiment, erroneous detection of the remaining amount of the developer due to the change in the capacitance between the electrodes despite the sufficient remaining of the developer T is prevented. be able to.

Embodiment 2 Next, another embodiment of the present invention will be described. Since the electrophotographic image forming apparatus and the process cartridge of this embodiment are basically the same as those of the first embodiment, the same reference numerals are given to the elements having the same configuration and function, and the detailed description is omitted.

FIG. 9 is an enlarged view of the concave portion 30 formed by the first and second plate electrodes 31 and 32 disposed in the developing chamber 41 of the process cartridge B of this embodiment.

Also in the present embodiment, the upper end 31a of the first plate electrode 31 does not extend to the uppermost surface 30a of the concave portion 30 as in the first embodiment, but is lowered.

On the other hand, in the present embodiment, unlike the first embodiment, the second plate electrode 32 is
a or its upper end 32a up to the vicinity of the uppermost surface 30a.
Is higher.

In FIG. 9, the developer T that moves up and down in the concave portion 30 is indicated by hatching. As shown in the figure, by lowering the upper end 31a of the first plate electrode 31, which is one of the electrodes, the capacitance measurement area between the first and second plate electrodes 31, 32 is as follows. Become.

That is, in the upper end regions of the electrodes 31 and 32, a portion below the straight line connecting the upper ends 31a and 32a, where the electrodes 31 and 32 face each other, and in addition to this portion, the width is slightly wider. The electric field can be detected in a wraparound form.

That is, in response to a change in the amount of the developer (developer upper surface S) in the concave portion 30, only by lowering the height of the upper end 31a of one electrode (the first plate electrode 31),
Sufficiently dulling unnecessary sensitivity is achieved.

More specifically, in this embodiment, the first plate electrode 31 is the same as that of the first embodiment. On the other hand, the second plate electrode 32 moves the upper end 32a of the second plate electrode 32 of the first embodiment by the cut width w2.
That is, it extends to the uppermost surface portion 30a of the concave portion 30 by 9 mm (FIG. 4).

As a result, even if the amount of the developer (developer upper surface S) in the concave portion 30 sometimes changes during use of the process cartridge B, the amount of the remaining developer is erroneously detected. It does not reach the amount of change in the capacitance (detection voltage value V3).

In this embodiment, as described above, the sensitivity of the unstable detection area between the first and second plate electrodes 31 and 32 is reduced to prevent erroneous detection, and the second plate electrode 32 is extended to the upper surface 30a of the concave portion 30 to increase the area as much as possible,
The absolute value of the capacitance between the first and second plate electrodes 31, 32 is increased. As a result, the amount of change in the capacitance to be detected can be increased, and the detection accuracy can be increased.

The first and second plate electrodes 31, 32
The setting of the heights of the upper end portions 31a and 32a is not limited to the above-described embodiment. For example, the upper end portion of the first plate electrode 31 is raised, and the height of the second plate electrode 32 is increased. It may be lower (FIG. 10).

As described above, according to the configuration of the present embodiment, it is possible to minimize the detection of the electrostatic capacity in an unnecessary detection area where the amount of the developer is unstable and to minimize the first and second plates. By increasing the capacitance between the electrodes 31 and 32, the amount of change can be increased. As a result, detection accuracy can be increased and erroneous detection can be prevented.

Embodiment 3 Next, another embodiment of the present invention will be described. Since the electrophotographic image forming apparatus and the process cartridge of this embodiment are basically the same as those of the first embodiment, the same reference numerals are given to the elements having the same configuration and function, and the detailed description is omitted.

FIG. 11 is an enlarged view of the concave portion 30 formed by the first and second plate electrodes 31 and 32 disposed in the developing chamber 41 of the process cartridge B of this embodiment.

In this embodiment, unlike the above embodiments,
Upper end portions 31a of the first and second plate electrodes 31, 32,
32a is arranged so as to extend to the uppermost surface of the concave portion 30.

This is a means for accurately arranging the electrodes. The first and second plate electrodes 31 and 32 are brought into contact with the uppermost surface 30a of the concave portion 30 by pressing the first and second plate electrodes 31 and 32.
The electrode assembly position accuracy can be improved, and the remaining amount detection accuracy can be increased.

In the present embodiment, in order to reduce the detection sensitivity of the developer region in which the unstable movement occurs in the concave portion 30 and to detect the remaining amount of the developer T with high accuracy, FIG.
As shown in FIG. 1, the first,
A burying member 33 is disposed between the second plate electrodes 31 and 32 as means for lowering the sensitivity. The filling member 33 is
The entry of the developer T into the upper portion between the first and second plate electrodes 31 and 32 is restricted.

As the filling member 33, a member made of, for example, resin or rubber other than conductive material is disposed. As a result, the developer region exhibiting an unstable behavior is filled in, and the sensitivity is reduced so as not to be detected.

That is, as in the first and second embodiments, the filling member 33 needs to be large enough to fill a portion where the behavior of the developer T is unstable. As a matter of course, the filling member 33 needs to have a length that covers the entire area in the longitudinal direction where the first and second plate electrodes 31 and 32 are arranged. The filling member 33 shown in FIG. 11 includes a developer T to a portion where the developer amount (developer upper surface S) near the upper end portions 31a and 32a of the first and second plate electrodes 31 and 32 is unstable.
It is configured to completely block the ingress of

More specifically, in the present embodiment, as the first plate electrode 31, the upper end 31a of the first plate electrode 31 of the first embodiment is replaced by the cut width w1, that is,
It extends to the upper surface 30a of the concave portion 30 by 9 mm. Further, the second plate electrode 32 is formed by cutting the upper end 32a of the second plate electrode 32 of the first embodiment with a cut width w2.
It extends to the upper surface 30a of the concave portion 30 by the distance, that is, 9 mm (FIG. 4).

Thus, the upper ends 31a, 32 of both electrodes are formed.
a is abutted on the upper surface 30 a of the concave portion 30.

The filling member 33 has a shape that completely fills the range of 9 mm downward from the upper ends 31a, 32a of the first and second plate electrodes 31, 32, even in the longitudinal direction.

The filling member 33 can be attached between the first plate electrode 31 and the second plate electrode 32 with an appropriate adhesive.

In the configuration of the present embodiment, the wraparound electric field portion other than the opposing surfaces of the first and second plate electrodes 31 and 32 is not detected.
It is slightly smaller than 2. After that, the amount of change in the capacitance after the developer T decreases is also slightly smaller.

However, it becomes possible to prevent the developer T from completely entering the region where the amount of the developer (developer upper surface S) is unstable. In addition, as described above, the assembling position accuracy of the first and second plate electrodes 31, 32 is improved.
Depending on the size of 3 and the accuracy of the mounting position, the accuracy of detecting the remaining amount of the developer can be sufficiently increased.

In the above description, the filling member 33 is a member having a substantially rectangular parallelepiped section in order to completely fill the upper portions of the first and second plate electrodes 31 and 32. However, the present invention is not limited to this. That is, in the second embodiment, the first plate electrode 31 in the region where the behavior of the developer T is unstable
In the same manner as the principle of shortening only the upper end portion 31a, the cross-sectional shape can fill only the portion where the behavior of the developer T is really unstable. For example, as shown in FIG. 12, a filling member 33 having a triangular cross section can be used.

As described above, according to the configuration of the present embodiment, the developer T is not completely introduced into an unnecessary detection area where the amount of developer (developer upper surface S) is unstable, and Is not detected, the remaining amount can be detected with high accuracy, and as a result, erroneous detection can be prevented.

Incidentally, from the beginning of the design of the process cartridge B, it is conceivable to set the shape of the concave portion 30 in consideration of a portion where the behavior of the developer T is unstable. However, the behavior of the developer T greatly differs depending on the externally added state of the developer T and the flowability due to the change of the external additive. In general, in the design of the process cartridge B, the prescription of the developer T is finally determined. Therefore, even if the prescription of the developer T is finally determined and its behavior is known, a situation in which the configuration of the frame such as the developing chamber 41 cannot be easily changed often occurs. Further, even when the configuration of the developing chamber 41 and the developer container 42 is changed from the initial design due to other factors, the force with which the developer T enters the concave portion 30 is changed. In such a case, it is very effective to use the filling member 33 which can be relatively easily changed in shape and incorporated between the process cartridge B, that is, the first and second plate electrodes 31 and 32. Become.

Embodiment 4 FIG. 13 shows an embodiment of a developing device (developing cartridge) C in the form of a cartridge, which is another aspect of the present invention.

The developing device C of the present embodiment includes a developing roller 4a
Developing chamber 4 supporting a developing member (developer carrier) such as
1 and a developer accommodating portion (developer container) 42 for accommodating the developer T to be supplied to the developing member.
Is formed integrally with the developer frame 42a. That is, the developing device C of the present embodiment is obtained by unitizing the developing device components of the process cartridge B described in the first to third embodiments, and the photosensitive drum 1, the charging roller 2, the cleaning It can be considered as a cartridge that is integrated except for the device 6 and is detachable from the device main body A. Therefore, all the configuration of the developing device and the configuration of the developer amount detecting device described in the first to third embodiments are similarly applied to the developing device C of the present embodiment. For the description of these configurations and operations, the above description in Examples 1 to 3 is cited.

[0106]

As described above, according to the present invention,
A developing member for supplying a developer to the electrophotographic photosensitive member for developing an electrostatic latent image formed on the electrophotographic photosensitive member; and a plurality of electrodes arranged substantially in parallel along a longitudinal direction of the developing member. Wherein at least two of the plurality of electrodes are disposed on two side surfaces of the concave portion having an opening below in a state where the developing device is mounted on the electrophotographic image forming apparatus; In order to detect the remaining amount of the developer in the electrophotographic image forming apparatus, a voltage is applied to at least one of the electrodes arranged on the two side surfaces of the concave portion, and the voltage is applied to at least two side surfaces of the concave portion. The developing device that generates an electric signal according to the capacitance between the electrodes is configured so that the detection sensitivity of the remaining amount of the developer in the upper portion of the concave portion is reduced, and
According to the present invention, an electrophotographic image forming apparatus and a process cartridge provided with such a developing device, and an electrophotographic image forming apparatus to which the process cartridge can be attached and detached, are provided. Can be detected. Further, according to the present invention, it is possible to prevent erroneous detection of the remaining amount of the developer due to a change in the capacitance between the electrodes even when the developer is sufficiently left.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an embodiment of an electrophotographic image forming apparatus according to the present invention.

FIG. 2 is a schematic sectional view of one embodiment of a process cartridge according to the present invention.

FIG. 3 is a perspective view of a developing chamber (developing frame) showing one embodiment of a mounting portion for first and second plate electrodes.

FIG. 4 is a schematic perspective view of one embodiment of first and second electrodes.

FIG. 5 is a schematic circuit diagram showing one embodiment of a developer amount detecting device.

FIG. 6 is a block diagram for explaining a control configuration of a storage unit provided in the process cartridge.

FIG. 7 is a graph showing a relationship between a voltage value detected by a developer amount detection device and a remaining amount of developer.

FIG. 8 is a schematic cross-sectional view of the vicinity of a developing chamber showing one embodiment of first and second electrodes.

FIG. 9 is a schematic cross-sectional view near a developing chamber showing another embodiment of the first and second electrodes.

FIG. 10 is a schematic sectional view near a developing chamber showing another embodiment of the first and second electrodes.

FIG. 11 is a schematic sectional view near a developing chamber showing another embodiment of the first and second electrodes.

FIG. 12 is a schematic sectional view near a developing chamber showing another embodiment of the first and second electrodes.

FIG. 13 shows a developing device (developing cartridge) according to the present invention.
FIG. 2 is a schematic cross-sectional view showing one embodiment.

FIG. 14 is a diagram illustrating an example of a developer remaining amount display.

FIG. 15 is a diagram showing another embodiment of the developer remaining amount display.

FIG. 16 is a view showing another embodiment of the developer remaining amount display.

FIG. 17 is a schematic sectional view showing the vicinity of a developing chamber showing an example of a conventional developer amount detecting means.

[Explanation of symbols]

 Reference Signs List 1 photosensitive drum (electrophotographic photosensitive member) 2 charging roller (charging means) 4 developing device 4a developing roller (developing member) 6 cleaning device 31 first plate electrode 32 second plate electrode 33 filling member (regulating member) A electron Photographic image forming apparatus body B Process cartridge C Developing cartridge

 ──────────────────────────────────────────────────続 き Continued from the front page F term (reference) 2F014 AC07 EA10 2H027 DD02 DE04 DE07 EE08 GA49 GA50 GB03 ZA07 ZA08 2H071 BA03 BA04 BA13 BA20 BA32 BA33 DA06 DA08 DA13 2H077 AA02 AA07 AA35 AB12 AB15 AD06 AD13 DA15 DA42 DA59 DA86 DB

Claims (30)

[Claims] 1. A developing device for developing an electrostatic latent image formed on an electrophotographic photosensitive member, which is used in an electrophotographic image forming apparatus, wherein the electrostatic latent image formed on the electrophotographic photosensitive member is developed. A developing member for supplying a developer to the electrophotographic photoreceptor, and a plurality of electrodes arranged substantially in parallel along a longitudinal direction of the developing member, and at least one of the plurality of electrodes The two electrodes are disposed on two side surfaces of a concave portion having an opening below when the developing device is mounted on the electrophotographic image forming apparatus. In order to detect the remaining amount of
A voltage is applied to at least one of the electrodes disposed on one of the side surfaces, and the developing device generates an electric signal according to a capacitance between the electrodes disposed on at least the two side surfaces of the concave portion. A developing device for detecting the remaining amount of the developer in the upper portion of the concave portion. 2. The method according to claim 1, wherein the upper end of at least one of the electrodes disposed on two side surfaces of the concave portion is provided as means for lowering the detection sensitivity of the remaining amount of the developer in the upper portion of the concave portion. 2. The developing device according to claim 1, wherein the height is lower than the uppermost portion of the concave portion. 3. As a means for lowering the detection sensitivity of the remaining amount of the developer in the upper portion of the concave portion, the developer is restricted from entering the upper portion between the electrodes arranged on two side surfaces of the concave portion. 2. The developing device according to claim 1, further comprising a regulating member. 4. The developing device according to claim 3, wherein the regulating member completely prevents the developer from entering at least one upper end of the electrodes arranged on two side surfaces of the concave portion. 5. The developing device according to claim 3, wherein said regulating member is a member other than a conductive member. 6. A first electrode and a second electrode which are closer to the developing member on two side surfaces of the concave portion, respectively, and a voltage is applied to the developing member and the second electrode. Is applied, via the first electrode, an electric signal corresponding to the capacitance between the developing member and the first electrode and between the first electrode and the second electrode. The developing device according to any one of claims 1 to 5, which generates the following. 7. The developing device according to claim 6, wherein said first electrode and said second electrode are plate-shaped. 8. A process cartridge detachable from a main body of an electrophotographic image forming apparatus, comprising: (a) an electrophotographic photosensitive member; and (b) an electrostatic latent image formed on the electrophotographic photosensitive member. A developing member for supplying a developer to the electrophotographic photoreceptor; and a plurality of electrodes arranged substantially in parallel along a longitudinal direction of the developing member, wherein at least two of the plurality of electrodes are The process cartridge is mounted on the two side surfaces of the concave portion having an opening downward in a state where the process cartridge is mounted on the main body of the electrophotographic image forming apparatus. In order to detect the amount, a voltage is applied to at least one of the electrodes disposed on the two side surfaces of the concave portion, and a capacitance between at least the electrodes disposed on the two side surfaces of the concave portion. According to A developing device for generating an electric signal, comprising: a developing device for lowering a detection sensitivity of a remaining amount of a developer in an upper portion of the concave portion. 9. As means for lowering the detection sensitivity of the remaining amount of the developer in the upper part of the concave part, the upper end of at least one of the electrodes arranged on the two side surfaces of the concave part is formed. 9. The process cartridge according to claim 8, wherein the height is lower than the top of the concave portion. 10. A method according to claim 1, wherein said detecting means detects the remaining amount of developer in the upper portion of said concave portion.
9. A restricting member for restricting entry of a developer into an upper portion between electrodes arranged on one side surface is arranged.
Process cartridge. 11. The process cartridge according to claim 10, wherein said regulating member completely prevents the developer from entering at least one upper end of the electrodes disposed on two side surfaces of said concave portion. 12. The process cartridge according to claim 10, wherein said regulating member is a member other than a conductive member. 13. A first electrode and a second electrode, which are closer to the developing member, are respectively disposed on two side surfaces of the concave portion, and a voltage is applied to the developing member and the second electrode. Is applied, via the first electrode, an electric signal corresponding to the capacitance between the developing member and the first electrode and between the first electrode and the second electrode. The process cartridge according to any one of claims 8 to 12, which generates the following. 14. The process cartridge according to claim 13, wherein said first electrode and said second electrode are plate-shaped. 15. The apparatus according to claim 8, further comprising at least one of charging means for charging said electrophotographic photosensitive member and cleaning means for cleaning said electrophotographic photosensitive member. The process cartridge according to 1. 16. An electrophotographic image forming apparatus for forming an image on a recording medium, comprising: (a) an electrophotographic photosensitive member; and (b) an electrostatic device for forming an electrostatic latent image on the electrophotographic photosensitive member. Latent image forming means; (c) a developing member for supplying a developer to the electrophotographic photosensitive member for developing an electrostatic latent image formed on the electrophotographic photosensitive member; A plurality of electrodes arranged substantially in parallel along, and at least two of the plurality of electrodes have openings downward when the developing device is mounted on the electrophotographic image forming apparatus. A developing device arranged on two side surfaces of the concave portion, the developing device having a reduced sensitivity for detecting a remaining amount of a developer in an upper portion of the concave portion; Voltage is applied to at least one of the electrodes arranged on the two sides Means for applying a voltage to generate an electric signal corresponding to a capacitance between electrodes arranged at least on two side surfaces of the concave portion, and detecting the remaining amount of the developer by measuring the electric signal. An electrophotographic image forming apparatus comprising: 17. A method according to claim 17, wherein the detecting sensitivity of the remaining amount of the developer in the upper portion of the concave portion is reduced.
17. The electrophotographic image forming apparatus according to claim 16, wherein the upper end of at least one of the electrodes arranged on one side is lower than the uppermost part of the concave portion. 18. A method according to claim 18, wherein said means for lowering the detection sensitivity of the remaining amount of the developer in the upper part of said concave portion is provided in said concave portion.
2. A restricting member for restricting entry of a developer into an upper portion between electrodes disposed on one side surface is disposed.
6. The electrophotographic image forming apparatus of 6. 19. The electrophotographic image forming apparatus according to claim 18, wherein the regulating member completely prevents the developer from entering at least one upper end of the electrodes arranged on two side surfaces of the concave portion. 20. An electrophotographic image forming apparatus according to claim 18, wherein said regulating member is a member other than a conductive member. 21. A first electrode and a second electrode, which are closer to the developing member, are respectively arranged on two side surfaces of the concave portion, and the developing member, the second electrode and A voltage between the developing member and the first electrode and between the first electrode and the second electrode via the first electrode. The electrophotographic image forming apparatus according to any one of claims 16 to 20, which generates an electric signal. 22. The electrophotographic image forming apparatus according to claim 21, wherein said first electrode and said second electrode are plate-shaped. 23. An electrophotographic image forming apparatus for detachably mounting a process cartridge and forming an image on a recording medium, comprising: (a) an electrophotographic photosensitive member; and an electrostatic latent member formed on the electrophotographic photosensitive member. A developing member for supplying a developer to the electrophotographic photoreceptor for developing an image, and a plurality of electrodes arranged substantially in parallel along a longitudinal direction of the developing member; At least two of the electrodes are a developing device which is disposed on two side surfaces of a concave portion having an opening below in a state where the process cartridge is mounted on the electrophotographic image forming apparatus main body, Mounting means for removably mounting a process cartridge comprising: a developing device having a lower detection sensitivity of the remaining amount of the developer in the upper part of the concave portion; and (b) an electrostatic latent on the electrophotographic photosensitive member. Electrostatic latent image forming means for forming an image; and (c) applying a voltage to at least one of the electrodes arranged on the two side surfaces of the concave portion, and applying at least two of the electrodes of the concave portion. Means for generating an electric signal in accordance with the capacitance between the electrodes arranged on the side surface and detecting the remaining amount of the developer by measuring the electric signal, comprising: apparatus. 24. An upper end of at least one of electrodes arranged on two side surfaces of the concave portion, as means for lowering the detection sensitivity of the remaining amount of the developer above the concave portion of the process cartridge. 24. The electrophotographic image forming apparatus according to claim 23, wherein a portion is lower than an uppermost portion of the concave portion. 25. As means for lowering the detection sensitivity of the remaining amount of the developer in the upper part of the concave part of the process cartridge, the developer is transferred to an upper part between electrodes arranged on two side surfaces of the concave part. 24. The electrophotographic image forming apparatus according to claim 23, wherein a restricting member for restricting entry is arranged. 26. The electrophotographic image forming apparatus according to claim 25, wherein the regulating member completely prevents the developer from entering at least one upper end of the electrodes arranged on two side surfaces of the concave portion. 27. The electrophotographic image forming apparatus according to claim 25, wherein said regulating member is a member other than a conductive member. 28. A first electrode and a second electrode which are closer to the developing member are arranged on two side surfaces of the concave portion of the process cartridge, respectively.
In the electrophotographic image forming apparatus main body, a voltage is applied to the developing member and the second electrode, via the first electrode,
28. An electric signal according to an electrostatic capacitance between the developing member and the first electrode and between the first electrode and the second electrode. 2. The electrophotographic image forming apparatus according to 1. 29. The electrophotographic image forming apparatus according to claim 28, wherein said first electrode and said second electrode are plate-shaped. 30. The process cartridge according to claim 23, wherein the process cartridge further comprises at least one of a charging unit for charging the electrophotographic photosensitive member and a cleaning unit for cleaning the electrophotographic photosensitive member. An electrophotographic image forming apparatus according to any one of the above items.