JP2010107699A - Process unit, photoreceptor cartridge and developing cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce unevenness in printing density caused by an influence of an angular moment acting on a developing cartridge, which is caused by the input of external power for rotating and driving a developing roller. <P>SOLUTION: The process unit includes: guide grooves 63 disposed in a photoreceptor cartridge 35, for supporting rotating shafts 52 disposed at both end parts in the center axis direction of the angular moment acting on the developing cartridge 36 by the external power inputted from a developing coupling 56 in the developing cartridge 36a; and a roller 57 disposed in the photoreceptor cartridge 35, for supporting a rib 67 disposed in a position other than a position between the rotating shafts 52 for the developing cartridge 36, in the center axis direction. The developing coupling 56 is disposed at one end in the center axis direction, the roller 57 is disposed while biased toward the developing coupling 56 side of the developing cartridge 36 in the state where the developing cartridge 36 is attached to the photoreceptor cartridge 35. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a process unit, a photosensitive cartridge, and a developing cartridge, and a developing cartridge having a developing roller that is rotationally driven to supply developer to an electrostatic latent image formed on a photosensitive drum is mounted on the photosensitive cartridge. Related to technology.

  2. Description of the Related Art Conventionally, a photosensitive cartridge that is provided with a photosensitive drum on one end side on which an electrostatic latent image is formed and is mounted on a laser printer is generally a developing roller that carries a developer on the outer peripheral surface of the photosensitive drum. A developing cartridge having a developing roller is mounted by pressing the outer peripheral surface.

JP-A-2007-127995 (Patent Document 1) is provided as this type of photosensitive member cartridge. In the photoreceptor cartridge of Patent Document 1, both ends of the developing cartridge in the direction of the central axis of the rotational moment generated in the developing cartridge by the input of external power for driving the developing roller provided at one end of the developing cartridge are paired with each other. The developing cartridge is supported by a single roller provided at the center portion in the direction of the central axis of the rotational moment while being supported by the guide groove.
JP 2007-127995 A

  However, in the photoconductor cartridge of Patent Document 1, when driven, external power is input only from one end portion in the direction of the rotational moment central axis of the developing cartridge, so that the developing cartridge on the external power side rotates the developing coupling. Twisted in the direction and distorted to sink into the photosensitive cartridge side. For this reason, the nip portion between the outer peripheral surface of the developing roller and the outer peripheral surface of the photosensitive drum is not parallel to the rotating shaft of the developing roller or the rotating shaft of the photosensitive drum, and there is a problem that the print density becomes non-uniform. .

  SUMMARY OF THE INVENTION An object of the present invention is to reduce non-uniformity in print density caused by the influence of a rotational moment acting on a developing cartridge by the input of external power for driving the developing roller to rotate.

In order to achieve this object, a process cartridge according to claim 1 is provided with a photosensitive cartridge including a photosensitive drum on which an electrostatic latent image is formed;
A developing cartridge comprising: a developing roller that is rotationally driven to supply a developer to the electrostatic latent image when mounted on the photosensitive cartridge; and a drive input unit that rotationally drives the developing roller; ,
Supporting both ends supported portions provided at both ends in the central axis direction of the rotational moment acting on the developing cartridge by the external power input from the drive input portion, provided in the photosensitive cartridge, in the developing cartridge. Both end support parts to perform,
An intermediate support portion that is provided in the photosensitive cartridge and supports an intermediate supported portion that is disposed at a position other than between the both-end supported portions in the developing cartridge in the central axis direction. Provided at one end in the central axis direction, and the intermediate support portion is biased toward the drive input portion side of the developing cartridge in the central axis direction in a state where the developing cartridge is mounted on the photosensitive cartridge. It is arranged.

  A process cartridge according to a second aspect of the present invention is the process cartridge according to the first aspect, wherein either the intermediate support portion or the intermediate supported portion is rotatably supported in the mounting direction of the developing cartridge with respect to the photosensitive cartridge. It is characterized by being composed of rollers.

  A process cartridge according to a third aspect of the present invention is the process cartridge according to the first or second aspect, wherein the developing cartridge includes a pair of shaft portions extending in the central axis direction at the both-end supported portions, Each of the shaft portions is supported.

  A process cartridge according to a fourth aspect is the process cartridge according to the third aspect, wherein the shaft portion is a bearing of a rotation shaft of the developing roller.

  A process cartridge according to a fifth aspect of the present invention is the process cartridge according to any one of the first to fourth aspects, wherein the rotation direction of the drive input portion is a direction in which the intermediate supported portion is pressed against the intermediate support portion. It is a feature.

  A process cartridge according to a sixth aspect is the process cartridge according to any one of the first to fifth aspects, wherein the developer is a pulverized toner obtained by pulverization.

According to a seventh aspect of the present invention, there is provided a photosensitive cartridge including a photosensitive drum on which an electrostatic latent image is formed, a developing roller that is rotationally driven to supply a developer to the electrostatic latent image, and the developing roller. In a photosensitive cartridge that can be mounted with a developing cartridge having a drive input unit for rotational driving,
In the developing cartridge, both end support portions that respectively support both end supported portions provided at both ends in the central axis direction of the rotational moment acting on the developing cartridge by external power input from the drive input portion;
An intermediate support portion that supports an intermediate supported portion that is disposed at a position other than between the both-end supported portions in the developing cartridge in the central axis direction;
The intermediate support portion is arranged to be biased toward the drive input portion of the developing cartridge in the central axis direction in a state where the developing cartridge is mounted on the photosensitive cartridge.

  The process cartridge according to an eighth aspect of the present invention is the process cartridge according to the seventh aspect, wherein the intermediate support portion is configured by a roller that is rotatably supported in the mounting direction of the developing cartridge with respect to the photosensitive cartridge. It is said.

  A process cartridge according to a ninth aspect of the present invention is the process cartridge according to the seventh or eighth aspect, wherein the developing cartridge includes a pair of shaft portions extending in the central axis direction at the both-end supported portions, The shaft portions are supported respectively.

  A process cartridge according to a tenth aspect is the process cartridge according to the ninth aspect, wherein the shaft portion is a bearing of a rotation shaft of the developing roller.

  A process cartridge according to an eleventh aspect of the present invention is the process cartridge according to any one of the seventh to tenth aspects, wherein the rotation direction of the drive input portion is a direction in which the intermediate supported portion is pressed against the intermediate support portion. It is a feature.

The developing cartridge according to claim 12 is attachable to a photosensitive cartridge including a photosensitive drum on which an electrostatic latent image is formed, and is rotationally driven to supply a developer to the electrostatic latent image. In a developing cartridge comprising a roller and a drive input unit for rotationally driving the developing roller,
Both ends supported at both ends in the central axis direction of the rotational moment acting on the developing cartridge by external power input from the drive input section and supported by the both ends supporting sections provided in the photosensitive cartridge. And
An intermediate supported portion that is disposed at a position excluding the space between the supported portions at both ends in the central axis direction, and is supported by an intermediate support portion provided in the photoconductor cartridge;
The intermediate supported portion is arranged to be biased toward the drive input portion of the developing cartridge in the central axis direction in a state where the developing cartridge is mounted on the photosensitive cartridge. .

  A process cartridge according to a thirteenth aspect of the present invention is the process cartridge according to the twelfth aspect, wherein the intermediate supported portion is configured by a roller that is rotatably supported in a mounting direction of the developing cartridge with respect to the photosensitive cartridge. It is a feature.

  A process cartridge according to a fourteenth aspect of the present invention is the process cartridge according to the twelfth or thirteenth aspect, wherein the both end supported portions extend in the rotation axis direction and are supported by the both end support portions of the photosensitive cartridge. A shaft portion is provided.

  A process cartridge according to a fifteenth aspect of the present invention is the process cartridge according to the fourteenth aspect, wherein the shaft portion is a bearing of a rotation shaft of the developing roller.

  A process cartridge according to a sixteenth aspect is the process cartridge according to any one of the twelfth to fifteenth aspects, wherein the rotation direction of the drive input portion is a direction in which the intermediate supported portion is pressed against the intermediate support portion. It is a feature.

  A process cartridge according to a seventeenth aspect is the process cartridge according to any one of the twelfth to sixteenth aspects, wherein the developer is a pulverized toner obtained by pulverization.

  As is apparent from the above description, according to the process cartridge of the first aspect, the developing cartridge can be stably supported by the both end support portion and the intermediate support portion of the photosensitive member cartridge.

  Furthermore, since the developing cartridge is supported by the intermediate support portion that is arranged to be biased toward the drive input portion, it is possible to prevent the developing cartridge from being distorted due to the influence of the rotational moment acting on the developing cartridge. Therefore, the contact portion between the photosensitive drum and the developing roller can always be kept parallel to the rotation shafts of the photosensitive drum and the developing roller, and nonuniformity in print density can be reduced.

  According to the process cartridge of the second aspect, friction between the developing cartridge and the photosensitive member cartridge can be reduced in a state where the developing cartridge is mounted on the photosensitive member cartridge. Therefore, when the developing cartridge is pressed toward the photosensitive drum in order to press the developing roller against the photosensitive drum, the pressing force applied to the developing cartridge can be efficiently transmitted to the photosensitive drum.

  According to the process cartridges of claims 3 and 4, since the developing cartridge can be supported using the shaft portion of the developing cartridge, the configuration of the photosensitive cartridge can be simplified.

  According to the process cartridge of the fifth aspect, since the rotational moment acts in a direction in which the developing cartridge on the intermediate supported portion side is pressed against the photosensitive member cartridge, the developing cartridge can be stably supported on the photosensitive member cartridge.

  According to the process cartridge of the sixth aspect, even when the pulverized toner having a large influence on the print density due to the variation in the pressing force of the developing roller against the photosensitive drum is used, the nonuniformity of the print density can be reduced.

  According to the photoreceptor cartridge of the seventh aspect, the developing cartridge can be stably supported by the both end support portion and the intermediate support portion of the photoreceptor cartridge.

  Furthermore, since the developing cartridge is supported by the intermediate support portion that is arranged to be biased toward the drive input portion, it is possible to prevent the developing cartridge from being distorted due to the influence of the rotational moment acting on the developing cartridge. Therefore, the contact portion between the photosensitive drum and the developing roller can always be kept parallel to the rotation shafts of the photosensitive drum and the developing roller, and nonuniformity in print density can be reduced.

  According to the photoconductor cartridge of the eighth aspect, friction between the developing cartridge and the photoconductor cartridge can be reduced in a state where the developing cartridge is mounted on the photoconductor cartridge. Therefore, when the developing cartridge is pressed toward the photosensitive drum in order to press the developing roller against the photosensitive drum, the pressing force applied to the developing cartridge can be efficiently transmitted to the photosensitive drum.

  According to the photoconductor cartridges of the ninth and tenth aspects, since the developing cartridge can be supported using the shaft portion of the developing cartridge, the configuration of the photosensitive cartridge can be simplified.

  According to the photoconductor cartridge of the eleventh aspect, it is possible to receive the rotational moment acting on the developing cartridge by the intermediate support portion excluding both axial ends of the developing cartridge.

  According to the developing cartridge of the twelfth aspect, the developing cartridge can be stably supported by the both end support portions and the intermediate support portion of the photosensitive member cartridge.

  Furthermore, since the developing cartridge is supported by the intermediate support portion that is arranged to be biased toward the drive input portion, it is possible to prevent the developing cartridge from being distorted due to the influence of the rotational moment acting on the developing cartridge. Therefore, the contact portion between the photosensitive drum and the developing roller can always be kept parallel to the rotation shafts of the photosensitive drum and the developing roller, and nonuniformity in print density can be reduced.

  According to the developing cartridge of the thirteenth aspect, friction between the developing cartridge and the photosensitive member cartridge can be reduced in a state where the developing cartridge is mounted on the photosensitive member cartridge. Therefore, when the developing cartridge is pressed toward the photosensitive drum in order to press the developing roller against the photosensitive drum, the pressing force applied to the developing cartridge can be efficiently transmitted to the photosensitive drum.

  According to the developing cartridge of the fourteenth and fifteenth aspects, the developing cartridge can be supported by using the shaft portion of the developing cartridge, so that the configuration of the photosensitive member cartridge can be simplified.

  According to the developing cartridge of the sixteenth aspect, the rotational moment acting on the developing cartridge can be received by the intermediate support portion excluding both end portions in the axial direction of the developing cartridge.

  According to the developing cartridge of the seventeenth aspect, even when pulverized toner having a large influence on the printing density due to the variation in the pressing force of the developing roller against the photosensitive drum is used, the non-uniformity of the printing density can be reduced.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, the overall configuration of the laser printer 1 to which the present invention is applied will be described.

  FIG. 1 is a schematic sectional side view of the laser printer 1.

  As shown in FIG. 1, the laser printer 1 includes a casing 2 including a top cover 18, a front cover 16, a rear cover 5, and the like. In this embodiment, the rear cover 5 side is the “rear side” of the laser printer 1, the front cover 16 side is the “front side” of the laser printer 1, the top cover 18 side is the “upper side”, and the paper feed cassette 6 side, which will be described later, is “lower”. Side ".

  In the casing 2, a paper feed unit 3, a scanning unit 26, a process unit 4, a fixing unit 20, a paper discharge unit 10 and the like are disposed at predetermined positions.

  The sheet feeding unit 3 includes a sheet feeding cassette 6, sheet feeding rollers 7 and 8 disposed on the upper front side of the sheet feeding cassette 6, and a pair of sheet feeding pads 9 disposed to face the sheet feeding roller 8. The registration roller 12 is provided. The paper feed cassette 6 is attached to the lower part of the casing 2 so as to be insertable / removable from the front side of the casing 2, and a paper pressing plate 13 and a spring 14 for urging the paper pressing plate 13 upward are provided in the paper feeding cassette 6. It is arranged.

  The uppermost sheet P stacked on the sheet pressing plate 13 is pressed and brought into contact with the sheet feeding roller 7 by the sheet pressing plate 13, and is conveyed between the sheet feeding roller 8 and the sheet feeding pad 9 by the sheet feeding roller 7. After that, the sheet passes through a pair of registration rollers 12 and is conveyed between the photosensitive drum 37 and the transfer roller 39 in the process unit 4.

  The scanning unit 26 is disposed at the upper part in the casing 2 and includes a laser light emitting unit (not shown), a polygon mirror 29 that is driven to rotate at high speed, scanning lenses 30 and 31, folding mirrors 32 and 33, and the like. In the scanning unit 26, the laser beam (two-dot chain line in the figure) emitted from the laser emission unit is sequentially reflected on the polygon mirror 29, the first scanning lens 30, the folding mirror 32, the second scanning lens 31, and the folding mirror 33. Alternatively, the light is transmitted and irradiated to the outer peripheral surface of the photosensitive drum 37 in the process unit 4.

  The process unit 4 is mounted at the center of the casing 2 and includes a photosensitive cartridge 35 and a developing cartridge 36. Further, the process unit 4 can be inserted and removed from the front side of the casing 2 by opening the front cover 16.

  The developing cartridge 36 includes a developing roller 40 having a rotation shaft 52, a layer thickness regulating blade 41, a supply roller 42, a hopper 43, and the like. The developing roller 40 is driven to rotate clockwise in FIG.

  The photoconductor cartridge 35 includes a photoconductor drum 37 rotatably supported on the rear side of the developing roller 40, a charger 38 disposed above the photoconductor drum 37, and below the photoconductor drum 37. The transfer roller 39 etc. which are arrange | positioned are provided.

  In the photoconductor cartridge 35, the outer peripheral surface of the photoconductor drum 37 is uniformly charged by the charger 38 and is exposed by the laser beam emitted from the scanning unit 26 to form an electrostatic latent image. Then, after the developer carried on the outer peripheral surface of the developing roller 40 is supplied to the electrostatic latent image and the electrostatic latent image is developed as a developer image, the developer image is brought into contact with the outer peripheral surface of the photosensitive drum 37. The image is transferred onto the paper P conveyed between the outer peripheral surface of the transfer roller 39. Note that the developer contained in the developing cartridge 36 is pulverized toner.

  The fixing unit 20 is disposed on the rear side of the process unit 4. The heating roller 21 is rotatably supported on the rear side of the process unit 4, and the pressure is disposed below the heating roller 21. A roller 22 is provided.

  In the fixing unit 20, the developer image transferred onto the paper P in the process unit 4 is heat-fixed by the heating roller 21 and the pressure roller 22, and then formed on the paper discharge unit 10 as a conveyance path of the paper P. The paper P is conveyed to the paper discharge path 45.

  The paper discharge unit 10 is disposed on the rear side in the casing 2 and includes a pair of paper discharge rollers 47 and 48, a paper discharge tray 46, and the like. In the paper discharge unit 10, the paper P that has passed through the fixing unit 20 and is transported to the paper discharge path 45 is transported upward in the casing 2, and is placed on the paper discharge tray 46 by a pair of paper discharge rollers 47 and 48. To discharge.

  Hereinafter, the part which concerns on this invention in the laser printer 1 is demonstrated in detail.

  2A is a side view when the process unit 4 is viewed from the left side when viewed from the front side, and FIG. 2B is a side view when the process unit 4 is viewed from the right side when viewed from the front side. FIG. 3 is a perspective view of the developing cartridge 36 as viewed from below, and FIG. 4 is a perspective view of the photosensitive cartridge 35 as viewed from above.

  As shown in FIG. 2, the process unit 4 is configured by mounting a developing cartridge 36 on a casing 50 of a photoreceptor cartridge 35 described later.

  The developing cartridge 36 includes a casing 51 having left and right side walls 53 and 54, and a developing roller 40 (see FIG. 1) is provided in the rear end portion of the casing 51. Both end portions of the rotation shaft 52 of the developing roller 40 protrude from the side walls 53 and 54 at both left and right ends of the casing 51. The rotating shaft 52 of the developing roller 40 is provided with bearing bodies 55 as bearings at both ends thereof so as to be rotatable with respect to the rotating shaft 52.

  Further, the developing cartridge 36 is provided with a developing coupling 56 in the vicinity of the front side of the bearing body 55 on the left side wall 53 of the casing 51. The developing coupling 56 is joined to a casing side coupling (not shown) that transmits a driving force from a motor (not shown) provided in the casing 2 to the process unit 4 side, so that the rotating shaft of the developing roller 40 is connected. 52, the developing roller 40 is rotated. That is, the developing cartridge 36 is configured such that external power for rotating the developing roller 40 is input only from the left side of the casing 51.

  The casing side coupling is interlocked with the front cover 16, and when the front cover 16 is opened, the engagement with the development coupling 56 is released and the direction away from the development coupling 56 (see from the front side in FIG. 1). When the front cover 16 is closed, it moves in a direction approaching the development coupling 56 (from the front to the right in FIG. 1) and engages with the development coupling 56.

  The development coupling 56 is rotated in the clockwise direction in FIG. 2A, and external power input to the development coupling 56 is generated by a gear (not shown) connected to the development coupling 56 and the development roller 40. This is transmitted to the rotation shaft 52 of the developing roller 40 via a gear (not shown) connected to the rotation shaft 52.

  Further, as shown in FIG. 3, the intermediate supported portion on the bottom surface of the casing 51 of the developing cartridge 36 is in contact with a roller 57 of the photosensitive cartridge 35 to be described later when the developing cartridge 36 is mounted on the photosensitive cartridge 35. The rib 67 is provided. The rib 67 has three projecting portions 69 to 71 erected from the bottom surface of the casing, and the projecting portion 70 disposed at the center contacts the roller 57. Note that the contact portion with the roller 57 on the photosensitive cartridge 35 side may be a flat surface instead of the rib 67.

  Further, the developing cartridge 36 has an opening 68 (see FIG. 1) formed at the rear end portion of the casing 51, and the outer peripheral surface of the developing roller 40 is exposed from the opening 68. In a state where it is mounted on the cartridge 35, it comes into contact with a photosensitive drum 37 of a photosensitive cartridge 35 described later.

  As shown in FIG. 4, the photoconductor cartridge 35 includes a casing 50 having left and right side walls 59 and 60, and a photoconductor drum 37 is disposed at the rear end of the casing 50. Then, both end portions of the rotating shaft 58 of the photosensitive drum 37 protrude from the side walls 59 and 60 at both left and right ends of the casing 50 (only the left rotating shaft is shown in FIG. 4). Although the upper portion of the photosensitive drum 37 is covered with the upper cover 61 disposed at the rear end portion of the casing 50, the outer peripheral surface is exposed toward the front side of the casing 50.

  The photoreceptor cartridge 35 is formed with a housing portion 62 for housing the developing cartridge 36 on the front side of the casing 50. The accommodating portion 62 has a single roller 57 as an intermediate support portion for supporting a rib 67 provided on the developing cartridge 36 on a bottom surface biased to the left side from the central portion between the left and right end portions in the front portion. It is pivotally supported so that it can rotate in the front-rear direction. The left side from the center between the left and right ends of the housing portion 62 is the left side from the front side shown in FIG. 4, and is the side where the developing coupling 56 is located when the developing cartridge 36 is mounted.

  The photosensitive cartridge 35 serves as a both-end support portion that guides to the vicinity of the rotating shaft 58 of the photosensitive drum 37 while slidably supporting the bearing body 55 of the developing cartridge 36 on the left and right side walls 59 and 60 of the casing 50, respectively. A guide groove 63 is formed.

  In addition, the photosensitive cartridge 35 has the developing cartridge 36 at the left and right end portions of the front end portion of the casing 50 so that the outer peripheral surface of the developing roller 40 uniformly contacts the outer peripheral surface of the photosensitive drum 37. 35 is provided with a pair of pressing mechanisms 64 that press in the direction of the rear end of the 35. The pressing mechanism 64 has a rotating shaft along the axial direction of the photosensitive drum 37, a lever portion 66 that rotates toward the photosensitive drum 37 (rear side), one end connected to the lever portion 66, and the other end. And a coil spring (not shown) connected to the casing 50. With the developing cartridge 36 mounted, the lever portion 66 is rotated to the photosensitive drum 37 side (developing cartridge 36 side) and brought into contact with the casing 51 of the developing cartridge 36. The developing roller 40 is pressed against the photosensitive drum 37 by pushing the casing 51 of the developing cartridge 36 rearward by the restoring force of the coil spring.

  In the laser printer 1 configured as described above, a series of operations for mounting the process unit 4 in the casing 2 and driving the laser printer 1 will be described.

  First, the developing cartridge 36 is mounted in the accommodating portion 62 of the photosensitive cartridge 35 so that the bearing bodies 55 at both ends are guided by the guide grooves 63. In this state, the protruding portion 70 of the rib 67 formed on the developing cartridge 36 contacts the roller 57 of the photoconductor cartridge 35. Next, the lever portion 66 of the pressing mechanism 64 provided in the casing 50 of the photosensitive member cartridge 35 is rotated to the photosensitive drum 37 side, the developing cartridge 36 is urged to the front side, and the developing roller with respect to the photosensitive drum 37 is developed. 40 is pressed. In this state, the developing cartridge 36 is stably supported in the storage portion 62 by the bearing bodies 55, the guide grooves 63, the ribs 67, and the rollers 57 at both left and right ends.

  Then, the front cover 16 is opened, and the photosensitive member cartridge 35 (process unit 4) with the developing cartridge 36 mounted in the casing 2 is mounted. At this time, in conjunction with the closing of the front cover 16, the casing side coupling that has moved in the direction away from the developing coupling 56 moves in the direction approaching the developing coupling 56 and engages with the developing coupling 56. . In this state, the nip portion between the outer peripheral surface of the photosensitive drum 37 and the outer peripheral surface of the developing roller 40 is parallel to the rotation shafts 52 and 58 of the photosensitive drum 37 and the developing roller 40.

  When driving is started at the time of printing or the like, the developing coupling 56 transmits the driving force transmitted from the casing side coupling to the rotating shaft 52 of the developing roller 40, and the developing roller 40 is rotationally driven. When the developing roller 40 is driven to rotate, due to this, the developing cartridge 36 has the developing cartridge 36 with the rotation shaft 52 of the developing roller 40 supported by the guide groove 63 of the photosensitive cartridge 35 as the central axis. A rotational moment acts such that the rear end of the developing cartridge 36 faces upward and the front end of the developing cartridge 36 faces downward.

  Further, since external power is input only from one end of the developing cartridge 36, the developing cartridge 36 on the developing coupling 56 side causes the developing coupling 56 to rotate in the direction of rotation of the developing coupling 56 (see FIG. 2A). And a force that sinks downward acts on the developing coupling 56 side of the developing cartridge 36 (particularly on the front side of the developing cartridge 36). Therefore, when the roller 57 that supports the developing cartridge 36 is disposed at the center of the photosensitive member cartridge 35 as in the prior art, the developing coupling 56 of the developing cartridge 36 is caused by the force that sinks downward in the developing cartridge 36. The side is distorted. Therefore, the nip portion between the outer peripheral surface of the developing roller 40 and the outer peripheral surface of the photosensitive drum 37 is not parallel to the rotating shafts 52 and 58 of the developing roller 40 and the photosensitive drum 37.

  According to the present invention, since the developing cartridge 36 is supported by the roller 57 that is biased and arranged on the developing coupling 56 side, it is possible to prevent the developing cartridge 36 from being distorted by the influence of the rotational moment acting on the developing cartridge 36. it can. Therefore, even during driving such as printing, since the nip portion between the outer peripheral surface of the developing roller 40 and the outer peripheral surface of the photosensitive drum 37 before driving can be maintained in a parallel state, nonuniformity in print density can be reduced. it can.

  Further, since the rib 67 of the developing cartridge 36 is supported by a roller 57 that can rotate in the mounting direction, the friction between the developing cartridge 36 and the photosensitive cartridge 35 can be reduced with the developing cartridge 36 mounted on the photosensitive cartridge 35. Can be reduced. Therefore, when the developing cartridge 36 is mounted on the photosensitive member cartridge 35, the pressing force loaded on the developing cartridge 36 by the pressing mechanism 64 can be efficiently transmitted to the photosensitive member cartridge 35.

  Further, in the process unit 4 of this embodiment, the guide groove 63 of the photosensitive cartridge 35 supports the rotating shaft 52 of the developing roller 40 so that the photosensitive member such as a member for supporting the rear end portion of the developing cartridge 36 is provided. It is not necessary to newly provide the cartridge 35, and the configuration of the photosensitive member cartridge 35 can be simplified.

Further, even when pulverized toner is used which has a great influence on the print density due to the variation in the pressing force of the developing roller 40 against the photosensitive drum 37, the non-uniformity of the print density can be reduced.
[Second Embodiment]
FIG. 5 shows a second embodiment of the present invention.

  FIG. 5 is a perspective view of the developing cartridge 36.

  In the present embodiment, the roller 65 is provided on the bottom surface that is biased to the left from the center between the left and right ends of the developing cartridge 36 facing the housing portion 62 of the photosensitive cartridge 35, and the housing portion of the photosensitive cartridge 35 is also provided. 62 is different from that of the first embodiment in that a rib (not shown) that abuts against the roller 65 is provided, and other configurations and effects are the same as those of the first embodiment. Is omitted. The roller 65 and the rib have the same configuration as in the first embodiment. As in the first embodiment, the contact portion of the roller 65 of the developing cartridge 36 may be a flat surface instead of a rib.

  In the first and second embodiments described above, either one of the photosensitive cartridge 35 or the developing cartridge 36 is provided with a roller and the other is provided with a rib that contacts the roller. The arcuate protrusions may be provided on the arcuate protrusions, and the arcuate protrusions may be brought into contact with the other plane.

  In the above embodiment, the present invention is applied to the laser printer to which the photosensitive cartridge can be attached and detached. However, the present invention may be applied to a laser printer in which only the developing cartridge can be attached and detached.

  In the above embodiment, the present invention is applied to a laser printer. However, the developing cartridge includes an image carrier on which an electrostatic latent image is formed, and a developer carrier that supplies developer to the electrostatic latent image. The present invention may be applied to any image forming apparatus that can be attached and detached.

1 is a schematic sectional side view of a laser printer according to a first embodiment of the present invention. (A) is a side view when the process unit is viewed from the left side when viewed from the front side, and (b) is a side view when the process unit is viewed from the right side when viewed from the front side. FIG. 3 is a perspective view of the developing cartridge as viewed from below. FIG. 3 is a perspective view of a photosensitive cartridge as viewed from above. FIG. 10 is a perspective view of the developing cartridge as viewed from below according to the second embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser printer 2 Casing 4 Process unit 35 Photosensitive cartridge 36 Developing cartridge 37 Photosensitive drum 40 Developing roller 50 Photosensitive cartridge casing 51 Developing cartridge casing 52 Developing roller rotating shaft (both ends supported part)
53, 54 Side wall 55 Bearing body 56 Development coupling 57, 65 Roller (roller)
58 Rotating shaft 62 of photosensitive drum 62 Accommodating portion 63 Guide groove (both ends supporting portion)
64 Pressing mechanism 67 Rib

Claims (17)

A photoreceptor cartridge comprising a photoreceptor drum on which an electrostatic latent image is formed;
A developing cartridge comprising: a developing roller that is rotationally driven to supply a developer to the electrostatic latent image when mounted on the photosensitive cartridge; and a drive input unit that rotationally drives the developing roller; ,
Supporting both ends supported portions provided at both ends in the central axis direction of the rotational moment acting on the developing cartridge by the external power input from the drive input portion, provided in the photosensitive cartridge, in the developing cartridge. Both end support parts to perform,
An intermediate support portion that is provided in the photosensitive cartridge and supports an intermediate supported portion that is disposed at a position other than between the both-end supported portions in the developing cartridge in the central axis direction. Provided at one end in the central axis direction, and the intermediate support portion is biased toward the drive input portion side of the developing cartridge in the central axis direction in a state where the developing cartridge is mounted on the photosensitive cartridge. Process unit characterized by being arranged.   2. The process unit according to claim 1, wherein one of the intermediate support portion and the intermediate supported portion is configured by a roller that is rotatably supported in a mounting direction of the developing cartridge with respect to the photosensitive cartridge. .   3. The developing cartridge includes a pair of shaft portions extending in the central axis direction at the both end supported portions, and the both end support portions respectively support the shaft portions. Process unit as described in   The process unit according to claim 3, wherein the shaft portion is a bearing of a rotation shaft of the developing roller.   5. The process unit according to claim 1, wherein a rotation direction of the drive input unit is a direction in which the intermediate supported unit is pressed against the intermediate support unit.   6. The process unit according to claim 1, wherein the developer is a pulverized toner obtained by pulverization. A photosensitive drum on which an electrostatic latent image is formed; a developing roller that is rotationally driven to supply developer to the electrostatic latent image; and a drive input unit that rotationally drives the developing roller. In the photosensitive cartridge in which the developed developing cartridge can be mounted,
In the developing cartridge, both end support portions that respectively support both end supported portions provided at both ends in the central axis direction of the rotational moment acting on the developing cartridge by external power input from the drive input portion;
An intermediate support portion that supports an intermediate supported portion that is disposed at a position other than between the both-end supported portions in the developing cartridge in the central axis direction;
The intermediate support portion is arranged to be biased toward the drive input portion of the developing cartridge in the central axis direction in a state where the developing cartridge is mounted on the photosensitive cartridge. cartridge.   The photoconductor cartridge according to claim 7, wherein the intermediate support portion includes a roller that is rotatably supported in a mounting direction of the developing cartridge with respect to the photoconductor cartridge.   8. The developer cartridge according to claim 7, wherein the developer cartridge includes a pair of shaft portions extending in the central axis direction at the both-end supported portions, and the both-end support portions respectively support the shaft portions. 9. A photosensitive member cartridge according to item 8.   The photosensitive member cartridge according to claim 9, wherein the shaft portion is a bearing of a rotation shaft of the developing roller.   The photosensitive member cartridge according to claim 7, wherein the rotation direction of the drive input unit is a direction in which the intermediate supported unit is pressed against the intermediate support unit. A developing roller that can be mounted on a photosensitive cartridge including a photosensitive drum on which an electrostatic latent image is formed, is rotated to supply developer to the electrostatic latent image, and the developing roller is rotated. In a developing cartridge comprising a drive input unit for
Both ends supported at both ends in the central axis direction of the rotational moment acting on the developing cartridge by external power input from the drive input section and supported by the both ends supporting sections provided in the photosensitive cartridge. And
An intermediate supported portion that is disposed at a position excluding the space between the supported portions at both ends in the central axis direction, and is supported by an intermediate support portion provided in the photoconductor cartridge;
The intermediate supported portion is arranged to be biased toward the drive input portion of the developing cartridge in the central axis direction in a state where the developing cartridge is mounted on the photosensitive cartridge. cartridge.   The developing cartridge according to claim 12, wherein the intermediate supported portion is configured by a roller that is rotatably supported in a mounting direction of the developing cartridge with respect to the photosensitive cartridge.   14. The both-end supported portion includes a pair of shaft portions that extend in the rotation axis direction and are supported by the both-end support portions of the photosensitive cartridge. Developer cartridge.   The developing cartridge according to claim 14, wherein the shaft portion is a bearing of a rotating shaft of the developing roller.   The developing cartridge according to claim 12, wherein the rotation direction of the drive input unit is a direction in which the intermediate supported unit is pressed against the intermediate support unit.   The developer cartridge according to claim 12, wherein the developer is pulverized toner obtained by pulverization.