JP4522235B2 - Developing device, process cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus using an electrophotographic system such as a copying machine, a printer, a facsimile machine, or a multifunction machine thereof, and a developing device and a process cartridge installed therein.

  Conventionally, in an image forming apparatus such as a copying machine or a printer, a flexible member (seal member) is provided at that position in order to reduce toner scattering from both ends in the width direction of the opening of the developing device facing the image carrier. There is known a technique for sticking (see, for example, Patent Document 1).

Specifically, an opening facing the image carrier (photosensitive drum) is provided in the case portion (housing) of the developing device. A part of the developer carrying member (developing roller) carrying the two-component developer (or one-component developer) is exposed in this opening. Then, the toner in the developer carried on the exposed developer carrying body adheres to the electrostatic latent image on the image carrying body, and a desired toner image is formed on the image carrying body. .
Here, in the case portion of the developing device, in order to prevent toner scattering from both ends in the width direction of the opening where a part of the developer carrying member is exposed, flexibility is provided to seal both ends in the width direction of the opening. A member (seal member) is attached.

  On the other hand, in Patent Document 1 or the like, air that escapes air in the vicinity of a position where a side seal (flexible member) is attached is intended to reduce toner scattering from both ends in the width direction at the opening of the developing device. A technique for forming a path is disclosed.

Japanese Patent No. 3247963 Specification

The conventional technology described above cannot sufficiently suppress toner scattering from both ends in the width direction at the opening of the developing device.
In particular, a developing device in which the rotation direction of the developer carrier is opposite to the conventional one (development so that the downstream side of the rotation direction of the developer carrier at the opening is the upper side of the gravity direction relative to the upstream side of the rotation direction In the developing device in which the agent carrier is rotationally driven), the above-mentioned toner scattering is a problem that cannot be ignored. Furthermore, in the case of using a substantially spherical toner having a small particle size in order to improve the image quality of the output image, the above-described toner scattering has been a problem that cannot be ignored.

  A conventional flexible member (seal member) has its three sides (upper side, lower side, one side) attached to the case portion of the developing device with a double-sided tape. That is, the flexible member after being attached to the case portion was in a state (bag-like attachment state) in which the other side was fixed without fixing only the side portion on the width direction center portion side. . Therefore, even if the flexible member is in close contact with the developer carrier when the developer carrier is not rotating, it is possible to slide by contact with the developer carrier when the developer carrier is rotated. In some cases, the flexible member is partially deformed, and a gap is generated between the developer carrier and the flexible member. In such a case, the toner in the developing device is scattered outside through the gap. In particular, since the flexible member is often made of a soft material in order to be close to the image carrier, the above-described deformation is likely to occur.

  In addition, when the three sides of the flexible member are attached to the case portion of the developing device with the double-sided tape, a gap is formed between the flexible member and the developer carrier (adhesion failure occurs). There was also a case. Even in such a case, the toner in the developing device is scattered to the outside through the gap. In particular, the case portion of the developing device is often configured to be separable into an upper case and a lower case in consideration of the assembling property of the developer carrier, and therefore, a gap ( Each time the upper case or the lower case is reassembled by adjusting the casing gap), the operation of removing the flexible member and the operation of pasting have occurred. For this reason, the above-described pasting failure is likely to occur.

  When the toner scatters from the developing device, a secondary problem that the inside of the image forming apparatus is contaminated with toner occurs. Furthermore, there may be a problem that the scattered toner adheres to the output image (referred to as “toner dropping”).

  On the other hand, in the technique disclosed in Patent Document 1 and the like, toner is scattered by adjusting the balance of pressure in the developing device by forming an air passage through which air is released near the position where the side seal (flexible member) is attached. To alleviate However, a space for providing an air passage is required in the developing device, which increases the size of the device and may complicate the configuration.

  The present invention has been made to solve the above-described problems, and a developing device capable of reliably suppressing toner scattering from both ends in the width direction at the opening of the developing device with a relatively simple configuration. A process cartridge and an image forming apparatus are provided.

A developing device according to a first aspect of the present invention is a developing device for developing a latent image formed on an image carrier, and a case portion having an opening at a position facing the image carrier. The developer carrying member that holds the developer and is held in the case portion so that a part is exposed from the opening, and the widthwise end portion of the developer carrying member that is exposed to the opening may be sealed. A flexible member, and the developer carrier is rotationally driven so that the downstream side in the rotational direction of the opening is the upper side in the gravitational direction with respect to the upstream side in the rotational direction. The upper case that constitutes the upper side of the opening and the lower case that is disposed on the lower side in the gravitational direction with respect to the upper case and that part of which constitutes the side and lower sides of the opening can be separated. wherein the flexible member, the sides and bottom of the opening Is adhered to the lower case a position near the sticking position, comprising a free end extending downstream in the rotation direction of the developer carrier with respect to the adhering position, the free end the opening it is intended to be loosely inserted between the upper case and the developer carrying member through.

According to a second aspect of the present invention, in the developing device according to the first aspect, the free end of the flexible member is loosely inserted into the developer carrier so as to be in close contact with the developer carrying member. It is.

  A developing device according to a third aspect of the present invention is the developing device according to the first or second aspect, wherein the developing device is located at a position facing the developer carrier and upstream in the rotational direction to the opening. A developer regulating member that regulates the amount of developer carried on the developer carrying member is provided.

A developing device according to a fourth aspect of the present invention is the developing device according to any one of the first to third aspects, wherein the upper case seals between the free end of the flexible member. The sealing member which stops is provided.

The developing device according to a fifth aspect of the present invention is the developing device according to any one of the first to fourth aspects, wherein the lower case is on the upstream side in the rotation direction of the developer carrier in the opening. A second flexible member extending in the width direction so as to face the image carrier is provided.

According to a sixth aspect of the present invention, there is provided the developing device according to any one of the first to fifth aspects, wherein the developer carrying member includes a magnet that forms a magnetic field on an outer peripheral surface thereof. Then, the magnet is disposed at the central portion in the width direction not including the end portion in the width direction of the developer carrier to be sealed with the flexible member.

According to a seventh aspect of the present invention, there is provided the developing device according to any one of the first to sixth aspects, wherein the developer carrying member includes a plurality of recesses on an outer peripheral surface thereof, The concave portion is formed at the central portion in the width direction not including the end portion in the width direction of the developer carrier to be sealed with the flexible member.

The developing device according to an eighth aspect of the present invention is the developing device according to any one of the first to seventh aspects, wherein the developer is formed so that an average circularity is 0.93 or more. Toner.

A process cartridge according to a ninth aspect of the present invention is a process cartridge that is detachably attached to the main body of the image forming apparatus, and the developing device according to any one of the first to eighth aspects. And the image carrier.

A process cartridge according to a tenth aspect of the present invention is the process cartridge according to the ninth aspect, wherein at least one of a charging unit that charges the image carrier and a cleaning unit that cleans the image carrier. One is further integrated.

An image forming apparatus according to an eleventh aspect includes the developing device according to any one of the first to eighth aspects and the image carrier.

According to a twelfth aspect of the present invention, in the image forming apparatus according to the eleventh aspect, a toner container that contains toner and is installed to be replaceable with respect to the main body of the image forming apparatus, and the toner container. And a toner conveying section that conveys the toner contained in the toner to the developing device.

  In the present application, the “process cartridge” refers to a charging unit that charges the image carrier, a developing device (developing unit) that develops a latent image formed on the image carrier, and a cleaning on the image carrier. At least one of the cleaning units and the image carrier are integrated and defined as a unit configured to be detachable from the main body of the image forming apparatus.

  In the present invention, the flexible member that seals the end portion in the width direction of the developer carrier is held in the case portion so that the downstream side in the rotation direction of the developer carrier in the opening is a free end. As a result, the flexible member comes into close contact with the developer carrier along the rotation of the developer carrier. Therefore, it is possible to provide a developing device, a process cartridge, and an image forming apparatus in which toner scattering from both ends in the width direction in the opening of the developing device is reliably suppressed with a relatively simple configuration.

Embodiment.
Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

First, the configuration and operation of the entire image forming apparatus will be described with reference to FIGS.
FIG. 1 is a block diagram showing a laser printer as an image forming apparatus, and FIG. 2 is a cross-sectional view showing the vicinity of a process cartridge installed therein. 3 is a cross-sectional view of the developing device and the photosensitive drum of the process cartridge of FIG. 2 as viewed from above (in the direction perpendicular to the plane of FIG. 2).

  As shown in FIG. 1, process cartridges 6Y, 6M, 6C, and 6K as image forming units corresponding to the respective colors (yellow, magenta, cyan, and black) are arranged so as to face the intermediate transfer belt 8 of the intermediate transfer unit 15. It is installed side by side. Since the four process cartridges 6Y, 6M, 6C, and 6K installed in the apparatus main body 100 have substantially the same structure except that the color of the toner used in the image forming process is different, the process cartridges in FIGS. The alphabets (Y, M, C, K) of the reference numerals for the cartridge 6, the photosensitive drum 1, and the primary transfer bias roller 9 are omitted.

  Referring to FIG. 2, a process cartridge 6 includes a photosensitive drum 1 as an image carrier, a charging unit 4 disposed around the photosensitive drum 1, a developing device 5 (developing unit), and a cleaning unit 2. Are integrated with each other and are detachable from the apparatus main body 100. Thus, the maintainability of the image forming unit is improved by integrating the components of the image forming unit. Then, an image forming process (charging process, exposure process, developing process, transfer process, cleaning process, charge eliminating process) is performed on the photosensitive drum 1 to form a desired toner image on the photosensitive drum 1. It will be.

  In the present embodiment, the photosensitive drum 1, the charging unit 4, the developing device 5, and the cleaning unit 2 are integrated to form the process cartridge 6. However, each component is formed as a single unit in the apparatus main body 100. It can also be installed detachably. Specifically, the developing device 5 can be configured to be detachable from the apparatus main body 100 as a single unit. Further, it can be configured to be detachable from the apparatus main body 100 as a unit in which at least one of the photosensitive drum 1, the charging unit 4, and the cleaning unit 2 and the developing device 5 are integrated.

Referring to FIG. 2, the photosensitive drum 1 is rotationally driven in a clockwise direction in FIG. 2 by a drive unit (not shown). Then, the surface of the photosensitive drum 1 is uniformly charged at the position of the charging unit 4 (a charging process).
Thereafter, the surface of the photosensitive drum 1 reaches the irradiation position of the laser beam L emitted from the exposure unit 7 (see FIG. 1), and an electrostatic latent image is formed by exposure scanning at this position. (It is an exposure process.)

Thereafter, the surface of the photosensitive drum 1 reaches a position facing the developing device 5, and the electrostatic latent image is developed at this position to form a desired toner image (developing process).
Specifically, a two-component developer G composed of toner and a carrier (magnetic carrier) is accommodated in the developing device 5. The developer G in the developing device 5 is adjusted so that the ratio (toner density) of the toner in the developer G detected by the toner density sensor 57 (magnetic sensor) is within a predetermined range. That is, according to the consumption of toner in the developing device 5, toner is replenished from the toner transport pipe 43 (toner transport unit) into the developer storage unit 54 via the toner supply port 44.

  The toner transport pipe 43 communicates with a corresponding toner bottle among the toner bottles 32Y, 32M, 32C, and 32K (toner containers) installed in the bottle container 31 above the apparatus main body 100 with reference to FIG. is doing. Although not shown in the figure, the toner transport unit includes a drive unit that rotationally drives the toner bottles 32Y, 32M, 32C, and 32K, a toner transport pipe 43, an air pump connected to the toner transport pipe 43, and the like. The toner transport unit configured as described above transports the respective color toners from the toner bottles 32Y, 32M, 32C, and 32K containing the respective color toners to the respective developing devices 5 through the toner transport pipe 43. .

  Thereafter, the toner replenished in the developer accommodating portion 54 is mixed and stirred together with the developer G by the second conveying screw 56 and the first conveying screw 55, and the two developer accommodating portions separated by the partition portion 59a are contained. It circulates through the parts 53 and 54 (circulation in the direction of broken arrows in FIG. 3). The toner in the developer G is attracted to the carrier by frictional charging with the carrier, and is carried on the developing roller 51 together with the carrier by a plurality of magnetic poles formed on the developing roller 51. Here, referring to FIG. 3, the developing roller 51 includes a magnet 51b that is fixed inside and forms a magnetic field on the peripheral surface of the roller, and a sleeve 51a that rotates around the magnet 23a1.

  The developer G carried on the developing roller 51 as the developer carrying member is conveyed as the developing roller 51 rotates in the direction of the arrow, and reaches the position of the doctor blade 52 as the developer regulating member. Then, after the developer G on the developing roller 51 is regulated to an appropriate amount at this position, the developer G is conveyed to a position facing the photosensitive drum 1 (developing area). The toner is attracted to the latent image formed on the photosensitive drum 1 by the electric field formed in the development area.

  Here, in the present embodiment, the developing roller 51 is rotationally driven so that the downstream side in the rotational direction at the opening 60 is above the upstream side in the gravitational direction (by the counterclockwise rotation indicated by the arrow in FIG. 2). is there.). Further, in accordance with such a configuration, the doctor blade 52 is disposed at a position facing the developing roller 51 and upstream in the rotational direction to the opening 60 (below the developing roller 51). As a result, the image forming unit 6 can be compactly disposed below the intermediate transfer belt.

  After the development process described above, the surface of the photosensitive drum 1 reaches a position facing the intermediate transfer belt 8 and the first transfer bias roller 9, and the toner image on the photosensitive drum 1 is transferred to the intermediate transfer belt 8 at this position. Transferred upward (this is a primary transfer step). At this time, a small amount of untransferred toner remains on the photosensitive drum 1.

Thereafter, the surface of the photoreceptor 1 reaches a position facing the cleaning unit 2, and untransferred toner remaining on the photoreceptor drum 1 at this position is collected by the cleaning blade 2a (cleaning process).
Finally, the surface of the photosensitive drum 1 reaches a position facing a neutralization unit (not shown), and the residual potential on the photosensitive drum 1 is removed at this position.
Thus, a series of image forming processes performed on the photosensitive drum 1 is completed.

  The image forming process described above is performed by each of the four process cartridges 6Y, 6M, 6C, and 6K. That is, referring to FIG. 1, laser light L based on image information is directed onto the photosensitive drums of the process cartridges 6Y, 6M, 6C, and 6K from the exposure unit 7 disposed below the process cartridge. Is irradiated. Specifically, the exposure unit 7 emits laser light L from a light source, and irradiates the photosensitive drum through a plurality of optical elements while scanning the laser light L with a polygon mirror that is rotationally driven. Thereafter, the toner images of the respective colors formed on the respective photosensitive drums through the developing process are transferred onto the intermediate transfer belt 8 in an overlapping manner. In this way, a color image is formed on the intermediate transfer belt 8.

  Here, referring to FIG. 1, the intermediate transfer unit 15 includes an intermediate transfer belt 8, four primary transfer bias rollers 9Y, 9M, 9C, and 9K, a secondary transfer backup roller 12, a counter roller 13, and a tension roller 14. And the cleaning unit 10 and the like. The intermediate transfer belt 8 is stretched and supported by the three roller members 12 to 14 and is moved endlessly in the direction of the arrow in FIG.

The four primary transfer bias rollers 9Y, 9M, 9C, and 9K respectively sandwich the intermediate transfer belt 8 with the photosensitive drums 1Y, 1M, 1C, and 1K to form a primary transfer nip. A transfer bias having a polarity opposite to the polarity of the toner is applied to the primary transfer bias rollers 9Y, 9M, 9C, and 9K.
The intermediate transfer belt 8 travels in the direction of the arrow and sequentially passes through the primary transfer nips of the primary transfer bias rollers 9Y, 9M, 9C, and 9K. In this way, the toner images of the respective colors on the photosensitive drums 1Y, 1M, 1C, and 1K are primarily transferred while being superimposed on the intermediate transfer belt 8.

  Thereafter, the intermediate transfer belt 8 on which the toner images of the respective colors are transferred in a superimposed manner reaches a position facing the secondary transfer roller 19. At this position, the secondary transfer backup roller 12 sandwiches the intermediate transfer belt 8 with the secondary transfer roller 19 to form a secondary transfer nip. The color toner image formed on the intermediate transfer belt 8 is transferred onto a transfer material P such as transfer paper conveyed to the position of the secondary transfer nip. At this time, the untransferred toner that has not been transferred to the transfer material P remains on the intermediate transfer belt 8.

Thereafter, the intermediate transfer belt 8 reaches the position of the cleaning unit 10 for the intermediate transfer belt 8. At this position, the untransferred toner on the intermediate transfer belt 8 is collected.
Thus, a series of transfer processes performed on the intermediate transfer belt 8 is completed.

Here, the transfer material P transported to the position of the secondary transfer nip is transported from a paper feed unit 26 disposed below the apparatus main body 100 via a paper feed roller 27, a registration roller pair 28, and the like. It has been done.
Specifically, a plurality of transfer materials P such as transfer paper are stored in the paper supply unit 26 in a stacked manner. When the paper feed roller 27 is rotated in the counterclockwise direction in FIG. 1, the uppermost transfer material P is fed between the rollers of the registration roller pair 28.

  The transfer material P conveyed to the registration roller pair 28 is temporarily stopped at the position of the roller nip of the registration roller pair 28 that has stopped rotating. Then, the registration roller pair 28 is rotationally driven in synchronization with the color image on the intermediate transfer belt 8, and the transfer material P is conveyed toward the secondary transfer nip. In this way, a desired color image is transferred onto the transfer material P.

Thereafter, the transfer material P on which the color image has been transferred at the position of the secondary transfer nip is conveyed to the position of the fixing unit 20. At this position, the color image transferred to the surface is fixed on the transfer material P by heat and pressure generated by the fixing roller and the pressure roller.
Thereafter, the transfer material P is discharged out of the apparatus through the rollers of the discharge roller pair 29. The transferred P discharged from the apparatus main body 100 by the discharge roller pair 29 is sequentially stacked on the stack unit 30 as an output image.
Thus, a series of image forming processes in the image forming apparatus is completed.

Here, the photosensitive drum 1 has a base tube made of aluminum as a base layer, and a CGL layer (charge generation layer), a CTL layer (charge transport layer), and the like are formed thereon.
The sleeve 51a of the developing roller 51 is made of a nonmagnetic material such as aluminum, and grooves (concave portions) are formed on the outer peripheral surface thereof at a predetermined pitch in the circumferential direction (see FIG. 7). A DC developing bias is applied to the developing roller 51 from a power supply unit (not shown).
The doctor blade 52 can be formed of a magnetic metal such as iron or stainless steel, or can be formed of a nonmagnetic material such as a resin material or aluminum, or a magnetic material can be formed on a part of the nonmagnetic material. It can also be formed by sticking.

  The developing gap (the gap between the photosensitive drum 1 and the developing roller 51 at the facing position) is set to be 0.2 to 0.5 mm. Furthermore, the doctor gap (the gap between the developing roller 51 and the doctor blade 52) is set to be 0.2 to 0.5 mm.

In the present embodiment, the average circularity of the toner in the developer accommodated in the developing device 5 and the toner accommodated in the toner bottles 32Y, 32M, 32C, and 32K is 0.93 or more. The formed substantially spherical toner is used. As a result, it is possible to obtain a fine output image with less dust and good transferability and high image density reproducibility.
Here, the circularity of the toner particles is defined by the following equation.
Circularity = (perimeter of a circle having the same area as the projected area of the particle) / (perimeter of the projected particle image)
Therefore, when the circularity is 1.00, the toner particles have a true spherical shape. The average circularity of the toner can be typically measured using a flow type particle image measuring device “FPIA-2100” (manufactured by Toa Medical Electronics Co., Ltd.).

Further, the toner in the developer G in the developing device 5 and the toner in the toner bottles 32Y, 32M, 32C, and 32K are formed so that the weight average particle diameter is in the range of 3.5 to 7.5 μm. Has been.
As a measuring device for measuring the weight average particle diameter of the toner particles, “Coulter Counter TA-II” (manufactured by Coulter Inc.) or “Coulter Multisizer II” (manufactured by Coulter Inc.) can be used.

  Further, the toner in the present embodiment is manufactured through the following steps. First, at least a compound having an active hydrogen group in an organic solvent, a reactive modified polyester resin, a colorant, and a release agent are dissolved or dispersed to form a solution or dispersion. Then, the dissolved or dispersed material is dispersed in an aqueous medium containing resin fine particles. The organic solvent is removed from the dispersion obtained by reacting this with at least one of a crosslinking agent and an extender. Finally, the resin fine particles adhering to the surface are washed, and a part or all of the fine particles are detached to form a toner. The toner thus formed has a small particle diameter and is substantially spherical, and is a necessary condition for achieving high image quality.

The carrier in the developer G in the developing device 5 has a weight average particle diameter of 20 to 60 μm, a static resistance of 10 ¹⁰ to 10 ¹⁶ Ω · cm, and a saturation magnetization of 40 to 40. It is formed to be 90 emu / g.
Here, the static resistance (volume resistivity) of the carrier is the resistance value 30 seconds after DC1000V is applied between the two electrodes after the carrier is put between the parallel electrodes having a gap of 2 mm and tapped. This is a value obtained by converting a value measured with a high resist meter into a volume resistivity.
The saturation magnetization of the carrier is measured by the following measurement method using “VSM-P7-15” (manufactured by Toei Kogyo Co., Ltd.). That is, about 0.15 g of a sample was weighed, and the sample was filled in a cell (with an inner diameter of 2.4 mm and a height of 8.5 mm), and then measured under a magnetic field of 1000 oerste (Oe). It is a thing.

Furthermore, the carrier in the present embodiment has a resin coating layer on the surface of the core material. The resin coating layer of the carrier contains conductive particles in which a conductive coating layer comprising a tin dioxide layer and an indium oxide layer containing tin dioxide provided on the tin dioxide layer is provided on the surface of the substrate particles. ing. The conductive particles contained in the resin coating layer are formed so that the oil absorption is 10 to 300 ml / 100 g.
As the base particles of the conductive particles, at least one of aluminum oxide, titanium dioxide, zinc oxide, silicon dioxide, barium sulfide, and zirconium oxide can be used. The oil absorption amount of the conductive particles can be measured in accordance with “21 oil absorption amount” in JIS-K5101 “Pigment Test Method”.
The carrier thus formed has excellent durability.

Hereinafter, the side seal 63 as a flexible member installed in the developing device 5, which is characteristic in the present embodiment, will be described in detail.
FIG. 4 is a cross-sectional view showing an end of the process cartridge 6 in the width direction. Note that FIG. 2 described above is a cross-sectional view showing the central portion in the width direction of the process cartridge 6. FIG. 5 is a front view of the developing device 5 as viewed from the photosensitive drum 1 side.

  With reference to FIGS. 4 and 5, the case portion of the developing device 5 includes an upper case 58 and a lower case 59 that are separable, and an opening 60 is provided at a position facing the photosensitive drum 1. Part of the developing roller 51 held in the case portion is exposed from the opening 60 of the developing device 5. As described above, the toner in the developer G carried on the exposed developing roller 51 adheres to the electrostatic latent image on the photosensitive drum 1, and a desired toner image is formed on the photosensitive drum 1. Will be formed.

Side seals 63 as flexible members are installed at both ends in the width direction of the openings 60 of the case portions 58 and 59 of the developing device 5. The side seal 63 has a thickness of about 0.1 to 0.4 mm and can be formed of a material such as Mylar or polyurethane rubber.
The side seal 63 has a fixed end 63b on the lower case 59 side and a free end 63a on the upper case 38 side. Specifically, referring to FIG. 5, the side seal 63 has a lower side and a part of one side attached to the lower case 59 with a double-sided tape 68. Further, the upper side (free end 63a) of the side seal 63 is loosely inserted between the developing roller 51 and the upper case 58 (see FIG. 4). That is, the free end 63a of the side seal 63 is in a state of being peeled (unfixed) between the developing roller 51 and the upper case 58.

Since the side seal 63 configured in this manner has a free end 63 a on the downstream side in the rotation direction of the developing roller 51, the side seal 63 easily adheres to the developing roller 51 following the rotation of the developing roller 51. That is, the deformation of the side seal 63 accompanying the rotation of the developing roller 51 is reduced, and a gap between the side seal 63 and the developing roller 51 is less likely to occur. Therefore, toner scattering from both ends of the opening 60 in the developing device 5 is reliably reduced.
Further, the side seal 63 is attached only to the lower case 59 without being attached to the upper case 58. Therefore, even after the side seal 63 is adhered, adjusting the gap (casing gap) between the developing roller 51 and the upper case 58, or reassembling the upper case 58 and the lower case 59, This is possible without replacing the side seal 63.

  As shown in FIG. 6, a sealing member 64 made of a sponge material such as polyurethane foam is provided between the upper case 58 and the free end 63a of the side seal 63 (attached to the upper case 58 with a double-sided tape. In other words, the gap between the two is sealed, and the scattering of toner from there can be suppressed.

  Further, in the present embodiment, referring to FIG. 3, the magnet 51b provided in the developing roller 51 has a width-direction central portion (in FIG. 3) that does not include both end portions in the width direction where the side seals 63 are installed. This is the range indicated by H.). As a result, the magnetic field by the magnet 51b hardly acts on both ends of the developing roller 51 sealed with the side seal 63, and the developer G enters between the side seal 63 and the developer G. In addition, it is possible to suppress the problem of toner scattering.

  In the present embodiment, referring to FIG. 7, in order to reinforce the carrying force for developer G in developing roller 51, the surface of developing roller 51 (the surface of sleeve 51a) has a plurality of V-shapes. The groove part (recessed part) 51a1 is formed. The groove 51a1 on the developing roller 51 is formed in the center in the width direction (the range indicated by H in FIG. 3) not including both ends in the width direction where the side seals 63 are installed. As a result, the adhesion between the side seal 63 and the developing roller 51 can be maintained at both ends of the developing roller 51, and the occurrence of toner scattering can be reduced.

  2 and 5, the lower case 59 of the developing device 5 extends in the width direction so as to face the photosensitive drum 1 on the upstream side of the opening 60 in the rotation direction of the developing roller 51. An inlet seal 61 as a second flexible member is attached. Accordingly, it is possible to reduce toner scattering to the outside of the developing device 5 in the central portion in the width direction of the developing roller 51 (a region sandwiched between both ends in the width direction). The inlet seal 61 has a thickness of about 0.1 to 0.4 mm, and can be formed of a material such as Mylar or polyurethane rubber.

  2 and 4, an auxiliary seal member 62 extending in the width direction is attached to the lower case 59 of the developing device 5 so as to face the photosensitive drum 1. Thereby, even if the toner scatters from the opening 60 of the developing device 51, the scattered toner can be collected. The auxiliary seal member 62 has a thickness of about 0.1 to 0.4 mm and can be formed of a material such as Mylar or polyurethane rubber.

  As described above, in this embodiment, the side seal 63 that seals both ends in the width direction of the developing roller 51 is held by the case portion 59 so that the downstream side in the rotation direction of the developing roller 51 is the free end 63a. ing. As a result, the side seal 63 comes into close contact with the developing roller 51 along the rotation of the developing roller 51. Therefore, toner scattering from both ends in the width direction of the opening 60 of the developing device 5 is reliably suppressed with a relatively simple configuration.

  In this embodiment, a two-component developer is used as the developer G accommodated in the developing device 5, but a developing device using a one-component developer (a developer that does not contain a carrier). However, the present invention can be applied. That is, by installing side seals with free ends on the downstream side in the rotation direction of the developing roller 51 at both ends of the developing roller of the one-component developing system, the same effect as in the present embodiment can be obtained.

  Further, in the present embodiment, the developing roller 51 is rotationally driven so that the downstream side in the rotational direction of the opening 60 is above the upstream side in the gravitational direction. On the other hand, the present invention can be applied even when the developing roller 51 is configured to be rotationally driven so that the downstream side in the rotational direction of the opening 60 is below the upstream side in the direction of gravity. That is, by installing side seals in which the downstream side in the rotation direction of the developing roller 51 (in this case, the lower case side) is a free end at both ends of the developing roller, the same effect as this embodiment can be obtained. Obtainable.

  It should be noted that the present invention is not limited to the present embodiment, and it is obvious that the present embodiment can be modified as appropriate within the scope of the technical idea of the present invention, other than suggested in the present embodiment. is there. In addition, the number, position, shape, and the like of the constituent members are not limited to the present embodiment, and the number, position, shape, and the like suitable for implementing the present invention can be achieved.

1 is an overall configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention. 2 is a side sectional view showing the vicinity of a process cartridge in the image forming apparatus. FIG. FIG. 3 is a cross-sectional view of a part of the process cartridge of FIG. 2 as viewed from above. FIG. 3 is a side sectional view showing an end in the width direction of the process cartridge of FIG. 2. FIG. 3 is a front view of the developing device as viewed from the photosensitive drum side. FIG. 6 is a partially enlarged view showing the vicinity of the opening of the developing device. It is sectional drawing which shows a part of developing roller installed in a developing device.

Explanation of symbols

1, 1Y, 1M, 1C, 1K photosensitive drum (image carrier),
2 cleaning section, 4 charging section,
5 Development device (development unit),
6, 6Y, 6M, 6C, 6K process cartridge (imaging part),
32Y, 32M, 32C, 32K toner bottle (toner container),
43 Toner transport pipe (toner transport section),
51 developing roller (developer carrier), 51a sleeve,
51a1 groove (recess), 51b magnet,
52 Doctor blade (developer regulating member),
58 Upper case (case part), 59 Lower case (case part),
60 opening, 61 inlet seal (second flexible member), 62 auxiliary seal member,
63 side seal (flexible member), 63a free end, 63b fixed end,
64 sealing members, 68 double-sided tape,
100 Image forming apparatus main body (apparatus main body).

Claims (12)

A developing device for developing a latent image formed on an image carrier,
A case portion having an opening at a position facing the image carrier;
A developer carrying body that holds the developer and is held in the case portion so that a part is exposed from the opening;
A flexible member that seals the widthwise end of the developer carrier exposed to the opening;
With
The developer carrier is rotationally driven so that the downstream side in the rotational direction of the opening is the upper side in the gravity direction with respect to the upstream side in the rotational direction,
The case portion is
An upper case part of which constitutes the upper side of the opening;
A lower case which is disposed on the lower side in the direction of gravity with respect to the upper case, and a part of which constitutes a side and a lower side of the opening;
With separable,
The flexible member is attached to the lower case with the positions in the vicinity of the side and lower sides of the opening as attachment positions, and extends downstream in the rotation direction of the developer carrier relative to the attachment position. comprises a free end standing, developing device characterized in that it is loosely inserted between the free end through the opening said developer carrying member and the upper case. The developing device according to claim 1, wherein the free end of the flexible member is loosely inserted so as to be in close contact with the developer carrying member.   A developer regulating member that regulates the amount of developer carried on the developer carrying member at a position facing the developer carrying member and upstream in the rotation direction to the opening. The developing device according to claim 1 or 2. The developing device according to claim 1, wherein the upper case includes a sealing member that seals between the free end of the flexible member. The lower case includes a second flexible member extending in the width direction so as to face the image carrier on the upstream side of the opening in the rotation direction of the developer carrier. The developing device according to any one of claims 1 to 4. The developer carrier is provided with a magnet that forms a magnetic field on its outer peripheral surface,
6. The magnet according to claim 1, wherein the magnet is disposed at a central portion in a width direction not including an end portion in the width direction of the developer carrying member sealed by the flexible member. The developing device according to any one of the above. The developer carrier has a plurality of recesses on its outer peripheral surface,
The plurality of recesses are formed in a width direction central portion not including an end portion in the width direction of the developer carrying member sealed by the flexible member. The developing device according to any one of the above. The developing device according to claim 1, wherein the developer contains toner formed so that an average circularity is 0.93 or more. A process cartridge that is detachably installed on the main body of the image forming apparatus,
9. A process cartridge in which the developing device according to claim 1 and the image carrier are integrated. The process cartridge according to claim 9, wherein at least one of a charging unit that charges the image carrier and a cleaning unit that cleans the image carrier is further integrated. An image forming apparatus comprising the developing device according to claim 1 and the image carrier. A toner container that contains toner and is installed in a replaceable manner with respect to the image forming apparatus main body;
A toner transport unit that transports the toner contained in the toner container to the developing device;
The image forming apparatus according to claim 11, further comprising:

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