JP2012159655A - Photoreceptor unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoreceptor unit capable of protecting contact parts which come into contact with prescribed parts in a device body when attached to the device body.SOLUTION: A process unit 9 including a pair of left and right side plates 44 which integrally hold both left and right sides of photoreceptor drums 14 corresponding to each color is separately provided at the lower edge in the front side of each of the side plates 44 with: an inner side protrusion 37 which comes into contact with a second reference shaft 53 in a body casing 2 when the process unit 9 is attached to the body casing 2; and an outer side protrusion 41 which, when the process unit 9 is detached from the body casing 2 and is placed on a prescribed mounting surface 81, comes into contact with the mounting surface 81.

Description

  The present invention relates to a photoreceptor unit provided in an image forming apparatus employing an electrophotographic system.

  Conventionally, a so-called tandem type color printer in which photosensitive drums corresponding to yellow, magenta, cyan, and black are arranged in parallel is known as an electrophotographic color printer.

  As a photoreceptor unit provided in such a color printer, for example, a pair of left and right side plates that integrally hold each photosensitive drum is provided. When the drum unit is detached from the main body casing and placed on a desk or the like, A drum unit has been proposed in which a portion protruding downward is formed at the lower end of both side plates so that the photosensitive drum does not contact a desk or the like (see, for example, Patent Document 1).

JP 2007-178657 A

  However, in the drum unit described in Patent Document 1 described above, in the portion protruding downward, when trying to position the predetermined member of the main body casing, when the protruding portion is deformed by contact with a desk or the like, It becomes difficult to position the drum unit in the main casing.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a photosensitive unit that can protect a contact portion that comes into contact with a predetermined portion in the apparatus main body when the apparatus main body is mounted.

  In order to achieve the above-described object, the present invention provides a photosensitive unit that is detachably attached to an apparatus main body of an image forming apparatus, and the photosensitive unit is a plurality of photosensitive units arranged in parallel at intervals. A pair of side plates disposed opposite to each other in the longitudinal direction of the body, the two side plates being provided at a peripheral edge of the side plate upstream in the mounting direction in the mounting direction of the photosensitive unit; When the photoconductor unit is mounted on the apparatus main body, a contact part that is in contact with a predetermined part in the apparatus main body, and a peripheral part on the upstream side in the mounting direction of the side plate separately from the contact part And a contact portion that comes into contact with the placement surface when the photoreceptor unit is detached from the apparatus main body and placed on a predetermined placement surface.

  According to the present invention, the both side plates have a contact portion that comes into contact with a predetermined portion in the apparatus main body when the photoconductor unit is mounted on the apparatus main body, and a predetermined position when the photoconductor unit is detached from the apparatus main body. And a contact portion that is brought into contact with the placement surface when mounted on the placement surface of the photosensitive member unit separately at the peripheral edge portion on the upstream side in the mounting direction of the photosensitive member unit.

  Therefore, when the photosensitive unit is detached from the apparatus main body and placed on a predetermined placement surface, a contact portion different from the contact portion is brought into contact with the placement surface to protect the contact portion. Can do.

1 is a cross-sectional view illustrating a color printer as an embodiment of an image forming apparatus of the present invention. The process frame shown in FIG. 1 is shown, (a) is the perspective view seen from the left rear side, (b) is the principal part enlarged view seen from the side surface. It is the process frame shown in FIG. 1, Comprising: It is the perspective view seen from the left rear side of the state which removed the outer side board. It is the perspective view seen from the left front side which shows the main body casing shown in FIG. It is explanatory drawing explaining positioning with respect to the main body casing of the process unit shown in FIG. 1, Comprising: The mode which looked at the process unit from the left front side is shown. It is explanatory drawing explaining positioning with respect to the main body casing of the process unit shown in FIG. 1, Comprising: The mode which looked at the process unit from the left side is shown. It is explanatory drawing explaining positioning with respect to the main body casing of the process unit shown in FIG. 1, Comprising: The mode which looked at the process unit from the back side is shown. It is explanatory drawing explaining attachment and detachment of the process unit shown in FIG. 1, Comprising: A process unit moves to the front upper side from an attachment position, while an inner notch part remove | deviates from a 1st reference axis, and an inner side protrusion from a 2nd reference axis. Indicates a disconnected state. It is explanatory drawing explaining attachment and detachment of the process unit shown in FIG. 1, Comprising: A process unit is drawn out to the drawing-out position, and the state which the roller of the process unit contacted the stopper of the main body side guide rail from the rear side is shown. It is sectional drawing which shows the state which removed the process unit shown in FIG. 1 from the main body casing, and mounted in the mounting surface. It is sectional drawing which is a modification of a color printer and shows a modification in which a second reference axis is formed in a cylindrical shape. It is sectional drawing which is a modification of a color printer, Comprising: The 2nd reference axis is shown in the substantially U-shape. FIG. 10 is a cross-sectional view showing a modification of the color printer, in which a process unit is positioned by pressing a pressed portion provided at a front end portion of an outer plate by a pressing member provided on a front cover.

1. Overall Configuration of Color Laser Printer As shown in FIG. 1, a color printer 1 as an example of an image forming apparatus is a horizontal type direct tandem type color laser printer. The color printer 1 includes a paper feeding unit 3 for feeding paper P and an image forming unit 4 for forming an image on the fed paper P in a main body casing 2 as an example of the apparatus main body. I have.
(1) Main Body Casing The main body casing 2 is formed in a box shape having a substantially rectangular shape in side view that accommodates the paper feeding unit 3 and the image forming unit 4, and a process unit 9 described later is attached to and detached from one side wall thereof. A front cover 5 is provided. The front cover 5 is swingably provided with respect to the main body casing 2 with the lower end portion as a fulcrum.

In the following description, the side on which the front cover 5 is provided (the right side in FIG. 1) is the front side, and the opposite side (the left side in FIG. 1) is the rear side. In addition, when the color printer 1 is viewed from the front side, the left and right reference is used. That is, the front side in FIG. 1 is the left side, and the back side is the right side.
(2) Paper Feed Unit The paper feed unit 3 includes a paper feed tray 6 that accommodates the paper P. The paper feed tray 6 is detachably attached to the bottom of the main casing 2. A registration roller 7 as an example of a pair of conveying members is provided above the front end portion of the paper feed tray 6.

The sheets P stored in the sheet feed tray 6 are fed one by one toward both the registration rollers 7, and at a predetermined timing, the image forming unit 4 (photosensitive drum 14 (described later) and the conveyance belt 22 (described later). )).
(3) Image Forming Unit The image forming unit 4 includes a scanner unit 8, a process unit 9 as an example of a photoreceptor unit, a transfer unit 10 as an example of a belt unit, and a fixing unit 11.
(3-1) Scanner Unit The scanner unit 8 is disposed in the upper part of the main body casing 2. As indicated by the solid lines, the scanner unit 8 emits laser beams toward four photosensitive drums 14 (described later) based on the image data to expose the photosensitive drums 14 (described later).
(3-2) Process Unit (3-2-1) Configuration of Process Unit The process unit 9 is disposed below the scanner unit 8 and above the transfer unit 10, and includes one process frame 12 and And four developing cartridges 13 corresponding to the respective colors. In addition, the process unit 9 slides in the front-rear direction between a mounting position (see FIG. 1) where the image forming is possible with respect to the main body casing 2 and a drawing position (see FIG. 9) where the process unit 9 is pulled out from the main body casing 2. It is provided as possible. The process unit 9 is configured to be detachable from the main body casing 2 when the process unit 9 is disposed at the drawing position, and is replaceable with a new process unit 9.

  The process frame 12 is slidable in the front-rear direction with respect to the main body casing 2, and integrally includes four photosensitive drums 14 corresponding to the respective colors and four scorotron chargers 15 corresponding to the photosensitive drums 14. Hold on.

  Each photosensitive drum 14 is formed in a substantially cylindrical shape extending in the left-right direction (longitudinal direction, rotation axis direction), and is arranged in parallel at intervals in the front-rear direction. Specifically, a black photosensitive drum 14K, a yellow photosensitive drum 14Y, a magenta photosensitive drum 14M, and a cyan photosensitive drum 14C are sequentially arranged from the front side to the rear side.

  Each of the scorotron chargers 15 is disposed on the rear upper side of the corresponding photosensitive drum 14 so as to face the photosensitive drum 14 with a space therebetween.

  Each developing cartridge 13 is detachably supported on the process frame 12 above the photosensitive drum 14 so as to correspond to each photosensitive drum 14. Specifically, a black developing cartridge 13K, a yellow developing cartridge 13Y, a magenta developing cartridge 13M, and a cyan developing cartridge 13C are sequentially arranged from the front side to the rear side. Each developing cartridge 13 includes a developing roller 17.

  The developing roller 17 is rotatably supported at the lower end of the developing cartridge 13 so as to be exposed from the rear side, and is opposed to and in contact with the photosensitive drum 14 from the upper side.

Each developing cartridge 13 includes a supply roller 18 that supplies toner to the developing roller 17 and a layer thickness regulating blade 19 that regulates the thickness of the toner supplied to the developing roller 17. The toner corresponding to is stored.
(3-2-2) Development Operation in Process Unit The toner in the development cartridge 13 is supplied to the supply roller 18 and further supplied to the development roller 17, and positive polarity is provided between the supply roller 18 and the development roller 17. Is triboelectrically charged.

  The toner supplied to the developing roller 17 is regulated in thickness by the layer thickness regulating blade 19 as the developing roller 17 rotates, and is carried on the surface of the developing roller 17 as a thin layer having a constant thickness.

  On the other hand, the surface of the photosensitive drum 14 is uniformly positively charged by the scorotron charger 15 as the photosensitive drum 14 rotates, and then the laser beam (see the broken line in FIG. 1) from the scanner unit 8 is scanned at high speed. Is exposed. As a result, an electrostatic latent image corresponding to the image to be formed on the paper P is formed on the surface of the photosensitive drum 14.

When the photosensitive drum 14 further rotates, the toner that is carried on the surface of the developing roller 17 and is positively charged is supplied to the electrostatic latent image formed on the surface of the photosensitive drum 14. As a result, the electrostatic latent image on the photosensitive drum 14 is visualized, and a toner image by reversal development is carried on the surface of the photosensitive drum 14.
(3-3) Transfer Unit The transfer unit 10 is spaced apart from the registration roller 7 on the rear side of the registration roller 7 on the upper side of the sheet feeding unit 3 and on the lower side of the process unit 9 in the main body casing 2. In this way, they are arranged along the front-rear direction. The transfer unit 10 includes a driving roller 20 and a driven roller 21 as an example of a pair of roller members, a conveyance belt 22 as an example of an endless belt, and four transfer rollers 23.

  The driving roller 20 is provided at the rear end portion of the conveyance belt 22.

  The driven roller 21 is disposed at the front end portion of the conveyance belt 22 so as to face the driving roller 20 with a space in the front-rear direction.

  The conveyor belt 22 is wound around the driving roller 20 and the driven roller 21 so as to face each photosensitive drum 14 in the vertical direction, and an upper portion thereof is in contact with each photosensitive drum 14. Further, the conveyance belt 22 is rotated by the drive roller 20 so that the upper portion of the conveyance belt 22 that contacts each photosensitive drum 14 moves from the front side toward the rear side.

  Each transfer roller 23 is provided to face each photosensitive drum 14 with the upper portion of the transport belt 22 interposed therebetween.

Then, the paper P fed from the paper feeding unit 3 is transported by the transport belt 22 from the front side to the rear side so as to sequentially pass through the transfer positions where the photosensitive drums 14 and the transfer rollers 23 face each other. Is done. During the conveyance, the color toner images carried on the respective photosensitive drums 14 are sequentially transferred onto the paper P to form a color image.
(3-4) Fixing Unit The fixing unit 11 is disposed on the rear side of the transfer unit 10 and includes a heating roller 24 and a pressure roller 25 facing the heating roller 24. In the transfer unit 10, the color image transferred to the paper P is thermally fixed to the paper P by being heated and pressed while the paper P passes between the heating roller 24 and the pressure roller 25. .
(4) Paper discharge The paper P on which the toner image is fixed is conveyed so as to pass through a U-turn path (not shown), and is placed on a paper discharge tray 27 formed on the upper side of the scanner unit 8 by a pair of paper discharge rollers 26. The paper is ejected.
2. Details of Process Frame As shown in FIGS. 2 and 3, the process frame 12 includes a frame body 31, each photosensitive drum 14, and four drum subunits 30.
(1) Frame body The frame body 31 includes a pair of side plates 44, a front beam 34 as an example of a beam member, and a rear beam 35.

The both side plates 44 are formed in a substantially rectangular flat plate shape in a side view, and are opposed to each other with an interval in the left-right direction. Each of the side plates 44 includes an inner plate 32 and an outer plate 33 as examples of plate members.
(1-1) Inner plate As shown in FIG. 3, both inner plates 32 are sheet metals formed in a substantially rectangular shape in a side view extending in the front-rear direction by punching using the same press die. Oppositely arranged at intervals in the direction. Further, the front end portion of the inner plate 32 extends toward the front upper side. Further, the rear end portion of the inner plate 32 is formed in a substantially L shape in a side view as it is inclined upward toward the rear side and extends further upward.

  Both inner plates 32 are formed with an inner insertion hole 36 and an inner protrusion 37 as an example of the contact portion and the first contact portion at the front end portion, and at the rear end portion of the second contact portion. An inner cutout 38 is formed as an example.

  The inner plates 32 support the left and right ends of each photosensitive drum 14 via the bearing member 29 between the inner insertion hole 36 and the inner notch 38.

  The inner insertion hole 36 is formed through the upper end portion of the front end portion of the inner plate 32, and an insertion shaft 61 (described later) is inserted therethrough.

  The inner ridge 37 is formed in a substantially trapezoidal shape in a side view in which the lower side is shorter than the upper side so as to protrude downward from the lower end edge (lower peripheral edge portion) of the inner plate 32.

The inner notch 38 is formed in a substantially V-shaped notch that is opened rearward from the rear edge (the rear peripheral edge) of the inner plate 32 toward the front. The inner notch 38 receives a first reference shaft 52 (described later) when the process unit 9 is mounted on the main casing 2 (see FIG. 6).
(1-2) Outer plate As shown in FIG. 2, both outer plates 33 are made of resin, are side surfaces that are wider than the inner plate 32 in the vertical direction and have substantially the same length as the inner plate 32 in the front-rear direction. It is formed in a substantially rectangular shape. The both outer plates 33 are disposed opposite to each other with a space in the left-right direction on the outer side in the left-right direction of the inner plates 32. That is, the side plates 44 are configured such that the inner plate 32 and the outer plate 33 are combined.

  Both outer plates 33 are formed with an outer insertion hole 39 and an outer protrusion 41 as an example of a contact portion at the front end, and an outer notch 40 at the rear end.

  The outer insertion hole 39 is formed so as to penetrate the inner insertion holes 36 of both inner plates 32 in the left-right direction.

  The outer ridge 41 is disposed so as to face the inner ridges 37 of both inner plates 32 in the left-right direction. Further, the outer ridge 41 is formed in substantially the same shape as the inner ridge 37 (substantially trapezoidal shape in a side view whose lower side is shorter than the upper side), and has an outer dimension slightly larger than the inner ridge 37. That is, when projected in the left-right direction, the lower end edge of the outer ridge 41 is disposed below the lower end edge of the inner ridge 37 (FIG. 2B). In addition, the outer protrusion 41 is formed with a recess 42 that is recessed upward from the lower end edge at substantially the center in the front-rear direction. And the inner side protrusion 37 is exposed below in the recessed part 42, when projected in the left-right direction (FIG.2 (b)).

  The outer notch 40 is disposed so as to face the inner notch 38 of both inner plates 32 in the left-right direction. The outer notch 40 has substantially the same shape as the inner notch 38 (substantially V-shape opened rearward), and is larger than the inner notch 38. In the outer notch 40, the peripheral edge of the inner notch 38 is exposed when projected in the left-right direction.

  Both outer side plates 33 are provided with process side guide rails 46 and rollers 47.

  The process side guide rail 46 is formed as a protrusion that extends along the front-rear direction at the upper end portion of the outer plate 33 and protrudes outward in the left-right direction from the outer surface in the left-right direction of the outer plate 33. The process side guide rail 46 is formed over substantially the entire width of the outer side plate 33 in the front-rear direction.

The rollers 47 are rotatably provided on the left and right outer surfaces of the outer side plates 33 below the rear end portion of the process side guide rail 46.
(1-3) Front Beam and Rear Beam The front beam 34 is provided between the front end portions of the inner plates 32 and includes an insertion shaft 61.

  The insertion shaft 61 is inserted through the front beam 34 along the left-right direction. Further, both end portions in the left-right direction of the insertion shaft 61 penetrate from the front beam 34 through the inner insertion hole 36 (see FIG. 3) of the inner plate 32 and the outer insertion hole 39 (see FIG. 2) of the outer plate 33. It protrudes outward in the left-right direction. That is, both left and right end portions of the insertion shaft 61 function as protruding portions 43 that protrude outward in the left and right direction from the inner plate 32.

  A front grip 62 is formed at the center in the left-right direction of the front beam 34.

The rear beam 35 is installed between the rear ends of the inner plates 32. A rear grip 65 is formed at the center in the left-right direction of the rear beam 35.
(2) Drum subunits The drum subunits 30 are equidistant from each other in the front-rear direction so as to be disposed between the front beam 34 and the rear beam 35 on the rear side of each photosensitive drum 14 between the inner plates 32. Four are arranged in parallel with a gap.

Each drum subunit 30 is formed in a substantially triangular prism shape extending left and right. Each drum subunit 30 holds a scorotron charger 15 along the left-right direction.
3. Details of the Main Body Casing As shown in FIG. 4, the main body casing 2 includes a pair of side walls 51 as an example of side walls, a first reference shaft 52 as an example of a first connecting member, and an example of a second connecting member. The second reference shaft 53 is provided.

  Both side walls 51 are formed in a substantially flat plate shape made of metal, and are opposed to each other with an interval in the left-right direction. Further, support shaft insertion grooves 54 are formed in the both side walls 51. The side walls 51 are provided with a main body side guide rail 55 and a pressing mechanism 56 (see FIG. 6).

  The support shaft insertion groove 54 is disposed substantially at the center in the vertical direction at the front end portion of the side walls 51, extends from the front end edge of the side walls 51 toward the rear side, and is bent toward the rear lower side at the rear end portion. As shown, the notch is formed. The support shaft insertion groove 54 is formed with a groove width longer than the diameter of the insertion shaft 61 so as to receive the protruding portion 43 of the insertion shaft 61 without contact.

  The main body side guide rail 55 is formed as a pair of upper and lower ridges extending in the front-rear direction so as to extend across the support shaft insertion groove 54 and the first reference shaft 52 at approximately the center in the vertical direction of the left and right side walls of the main body casing 2. ing.

  The upper body side guide rail 55 guides the upper surface of the process side guide rail 46 when the process unit 9 is mounted. Further, the rear end portion of the upper body side guide rail 55 is bent so as to be inclined rearwardly.

  The rear main body side guide rail 55 supports the rollers 47 from below when the process unit 9 is mounted. Further, the rear end portion of the main body side guide rail 55 is bent so as to be inclined to the rear lower side. A stopper 73 having a substantially semicircular shape in side view is provided at the front end of the main body side guide rail 55 so as to bulge upward from the upper surface thereof.

  As shown in FIGS. 6 and 7, the pressing mechanism 56 is provided on the outer side in the left-right direction of the support shaft insertion groove 54 at the front ends of the side walls 51. Each pressing mechanism 56 includes a swing shaft 57 and a pressing arm 58 as an example of a pressing member.

  The swing shaft 57 is disposed below the support shaft insertion groove 54 and is provided so as to protrude outward in the left-right direction from the left-right outer surface of the side walls 51.

  The pressing arm 58 is formed in a substantially bowl shape extending in the vertical direction, and is supported on the swing shaft 57 so as to be swingable at the lower end portion. Further, the pressing arm 58 is disposed such that the upper end portion faces the support shaft insertion groove 54 from the outer side in the left-right direction. A compression spring 59 is connected to the upper surface of the pressing arm 58 on the rear surface. The pressing arm 58 is always urged downward by the compression spring 59 with the pivot shaft 57 as a fulcrum.

  As shown in FIGS. 4 and 7, the first reference shaft 52 is formed in a substantially cylindrical shape extending from the metal in the left-right direction, and connects the both side walls 51 on the upper side of the rear end portion of the transfer unit 10. As described above, the two side walls 51 are provided between the substantially central portions in the vertical direction.

The second reference shaft 53 is formed from a metal in a substantially cylindrical shape extending in the left-right direction, and connects both side walls 51 between both the registration rollers 7 and the driven rollers 21 (see FIG. 1). It spans between the front lower ends of the side walls 51. That is, the second reference shaft 53 is provided on the front side of the first reference shaft 52 with an interval.
4). Positioning of Transfer Unit and Process Frame As shown in FIGS. 1 and 4, the transfer unit 10 includes a driving roller 20, a driven roller 21, and a belt frame 63 that supports both left and right ends of each transfer roller 23.

  The belt frame 63 is formed in a substantially rectangular shape when viewed from the side, and includes a sheet conveyance guide portion 64 protruding forward at the upper front end portion thereof.

  The sheet conveyance guide portion 64 is formed in a substantially right triangle shape in a side view having a top portion directed toward the front side. Specifically, the sheet conveyance guide portion 64 has an upper surface formed so as to incline downward toward the front side continuously from the upper end edge of the transfer unit 10 and has a lower surface formed in a substantially linear shape extending in the front-rear direction. Has been. Further, the top portion (front end portion) of the sheet conveyance guide portion 64 is opposed to the nip portion between the registration rollers 7 from the rear side.

  The belt frame 63 is in contact with the second reference shaft 53 from above on the lower surface of the paper transport guide portion 64. Accordingly, the front end portion of the transfer unit 10 is positioned with respect to the second reference shaft 53.

  As shown in FIGS. 5 and 6, the process unit 9 has both inner notches 38 fitted on the first reference shaft 52 from the rear side, and both inner ridges 37 are formed on the sheet conveyance guide. The second reference shaft 53 is in contact with the second reference shaft 53 from the upper side on the outer side in the left-right direction of the portion 64.

  That is, the front outer peripheral surfaces of the left and right end portions of the first reference shaft 52 function as the first positioning portions 71 that are in contact with the inner peripheral edges of the inner notches 38 (see FIG. 7). Moreover, the upper end edge of the left-right direction both ends of the 2nd reference | standard axis | shaft 53 functions as the 2nd positioning part 72 contact | abutted to the lower end edge of both the inner side protrusions 37 (refer FIG. 7).

  At this time, the outer notch 40 does not interfere with the first reference shaft 52, and the outer protrusion 41 does not interfere with the second reference shaft 53.

  At this time, the protrusion 43 of the insertion shaft 61 is inserted into the rear end portion of the support shaft insertion groove 54. The insertion shaft 61 is inserted so as not to interfere with the peripheral portion of the support shaft insertion groove 54. Further, the protruding portion 43 of the insertion shaft 61 protrudes outward in the left-right direction of the side wall 51 via the support shaft insertion groove 54.

  The protruding portion 43 of the insertion shaft 61 protruding outward in the left-right direction of the side wall 51 has a component force on the rear side and the lower side when the pressing arm 58 of the pressing mechanism 56 is brought into contact with the front upper side. It is pressed toward the rear lower side so as to occur (see arrow in FIG. 6).

As a result, the front end portion of the process unit 9 is positioned with respect to the first reference shaft 52 such that the inner peripheral edges of both inner notch portions 38 are pressed against the first positioning portion 71. Further, the rear end portion of the process unit 9 is positioned with respect to the second reference shaft 53 so that the lower end edges of both inner ridges 37 are pressed against the second positioning portion 72.
5. Next, the slide operation of the process unit 9 will be described with reference to FIGS.

  In order to slide the process unit 9 from the mounting position to the drawing position, the front side gripping part 62 is gripped and the process unit 9 is pulled to the front upper side.

  Then, as shown in FIG. 8, the process unit 9 is guided from the mounting position to the front upper side by the main body side guide rail 55, the fitting of the inner notch 38 and the first reference shaft 52 is released, and the inner side The protrusion 37 is separated from the second reference shaft 53 upward. Further, the photosensitive drums 14 are separated upward with respect to the conveyor belt 22.

  Then, when the process unit 9 is continuously pulled to the front side, as shown in FIG. 9, the process unit 9 is guided to the front side by the main body side guide rail 55, and the roller 47 is moved to the stopper 73 of the main body side guide rail 55 from the rear side. By the contact, further forward sliding is restricted. Thereby, the process unit 9 is arranged at the drawing position, and the slide from the mounting position of the process unit 9 to the drawing position is completed.

  In order to remove the process unit 9 arranged at the drawing position from the main casing 2, the process is performed such that the rear gripping portion 65 is gripped while the front gripping portion 62 is gripped and the front end portion of the process unit 9 is pulled up. Pull out the unit 9 to the front upper side.

  Then, the roller 47 gets over the stopper 73 so that the upper end edge of the stopper 73 rolls, and the process unit 9 is detached from the main casing 2.

  In order to attach the process unit 9 to the main casing 2, the process unit 9 is operated in reverse to the case where the process unit 9 is detached from the main casing 2.

  Specifically, the front gripping part 62 and the rear gripping part 65 are gripped so as to pull up the front end of the process unit 9, and the rollers 47 come into contact with the rear upper surface of the stopper 73 while tilting the process unit 9. Then, the rear end portion of the process unit 9 is inserted into the main casing 2.

  Then, the roller 47 gets over the stopper 73 so as to roll on the upper edge of the stopper 73, and the rear end portion of the process unit 9 is inserted into the main casing 2.

After that, when the process unit 9 is leveled and pushed backward (mounting direction), the process unit 9 is guided backward from the pull-out position by the main body side guide rail 55, and then guided to the rear lower side. Arranged at the mounting position.
6). As shown in FIG. 10, when the process unit 9 detached from the main body casing 2 is placed on a placement surface 81 such as a desk, the lower end of the outer protrusion 41, and Compared to the state of being in contact with the mounting surface 81 at the front lower end portion of the outer plate 33 and being mounted in the main body casing 2, the rear end portion is inclined so as to be lifted upward.

  Thereby, each photosensitive drum 14 is spaced apart from the mounting surface 81 so as not to contact the mounting surface 81.

At this time, the inner ridge 37 is slightly spaced above the placement surface 81 in the recess 42 of the outer plate 33.
7). Operation and Effect (1) According to the color printer 1, as shown in FIGS. 6 and 7, the inner notches 38 are formed at the rear end edges of the pair of inner plates 32 of the process unit 9, and the front sides of the inner plates 32. A first positioning portion 71 that abuts the inner notch 38 is connected to the first reference shaft 52 that connects the both side walls 51 of the main body casing 2, and the second ridge that connects the both side walls 51 is provided. The reference shaft 53 is provided with a second positioning portion 72 that contacts the inner ridge 37.

  Then, the rear end portion of the process unit 9 is positioned by contact between the inner notch 38 and the first positioning portion 71, and the front end of the process unit 9 is determined by contact between the inner protrusion 37 and the second positioning portion 72. The part is positioned.

  In other words, the process unit 9 includes the first reference shaft 52 and the second reference shaft in which the peripheral portions of the inner plates 32 of the process unit 9 (the inner notch 38 and the inner protrusion 37) connect the both side walls 51 of the main casing 2. Positioning is performed by contacting the shaft 53.

  Specifically, both inner plates 32 are brought into contact with the first reference shaft 52 and the second reference shaft 53 many times at the periphery when the process unit 9 is taken in and out, such as when the developing cartridge is replaced. The

  At this time, the peripheral portions of the inner plates 32 are in contact with the first reference shaft 52 and the second reference shaft 53 extending in the left-right direction, so that the first reference shaft 52 and the second reference shaft 53 Is easy to deform.

  In other words, the first reference shaft 52 and the second reference shaft 53 are less likely to be deformed than the peripheral edges of the inner plates 32. That is, the first reference shaft 52 and the second reference shaft 53 are prevented from being deformed by contact with the inner plates 32.

  Therefore, the first positioning portion 71 and the second positioning portion 72 of the main body casing 2 can be prevented from being deformed, and the process unit 9 can be accurately positioned with respect to the main body casing 2.

  Moreover, the deformation | transformation in the peripheral part becomes large gradually by the contact | abutting with both the 1st reference shafts 52 and the 2nd reference shaft 53. Then, it becomes difficult to accurately position the process unit 9 on the main casing 2.

  However, before the deformation of the peripheral edge portions of both inner plates 32 becomes so large that the positioning of the process unit 9 with respect to the main body casing 2 is hindered, the process unit 9 is periodically removed due to, for example, deterioration of the photosensitive drum 14. Will be replaced.

  That is, if the process unit 9 is replaced periodically (at a normal frequency), deformation of the inner side plates 32 can be suppressed, and the process unit 9 can be accurately positioned with respect to the main casing 2.

As a result, the user can use the color printer 1 for a long period of time only by periodically replacing the process unit 9 which is a consumable item without repairing or replacing the expensive main casing 2.
(2) According to the color printer 1, the second reference shaft 53 is disposed between the driven roller 21 and the registration roller 7 as shown in FIG. 1.

  Therefore, the front end portion of the process unit 9 can be positioned with respect to the main body casing 2 in the vicinity of the registration roller 7.

As a result, the paper P can be smoothly conveyed from the registration roller 7 between the black photosensitive drum 14K and the conveyance belt 22.
(3) According to this color printer 1, as shown in FIG. 6, the pressing arm 58 of each pressing mechanism 56 is inserted toward the rear lower side so that a component force is generated between the rear side and the lower side. The protrusion 43 of the shaft 61 is pressed.

  Therefore, the inner peripheral edges of both inner notch portions 38 are pressed against the first positioning portion 71 to position the front end portion of the process unit 9 with respect to the first reference shaft 52, and at the same time, the lower end edges of both inner protrusions 37 are second. The rear end portion of the process unit 9 can be positioned with respect to the second reference shaft 53 by pressing against the positioning portion 72.

As a result, the front end portion and the rear end portion of the process unit 9 can be simultaneously positioned with a simple configuration.
(4) According to this color printer 1, as shown in FIG. 3, both inner side plates 32 are formed of sheet metal having the same shape punched by the same mold.

  Therefore, the shape of both the inner side plates 32 can be matched with each other with high accuracy.

As a result, the intervals in the front-rear direction of the photosensitive drums 14 can be accurately matched on the left and right sides.
(5) According to this color printer 1, the first reference shaft 52 and the second reference shaft 53 are made of metal.

  Therefore, the rigidity of the first reference shaft 52 and the second reference shaft 53 can be ensured.

The first positioning portion 71 and the second positioning portion are positioned by positioning the process unit 9 (the abutting of the inner notches 38 on the first positioning portion 71 and the abutting of the inner ridges 37 on the second positioning portion 72). The deformation of 72 can be further prevented.
(6) According to this color printer 1, the second reference shaft 53 is formed in a cylindrical shape extending in the left-right direction.

Therefore, the rigidity of the second reference shaft 53 can be ensured with a simple configuration, and the first positioning portion 71 and the second positioning portion 72 can be further prevented from being deformed.
(7) According to this color printer 1, as shown in FIG. 10, the both side plates 44 come into contact with the second reference shaft 53 in the main body casing 2 when the process unit 9 is mounted on the main body casing 2. The inner ridge 37 and the outer ridge 41 that comes into contact with the placement surface 81 when the process unit 9 is detached from the main body casing 2 and placed on the predetermined placement surface 81 are arranged on the front side. Separately provided at the lower edge.

Therefore, when the process unit 9 is detached from the main casing 2 and placed on the predetermined placement surface 81, the outer projection 41 other than the inner projection 37 is brought into contact with the placement surface 81, The ridge 37 can be protected.
(8) According to the color printer 1, the inner ridge 37 is provided on the metal inner plate 32, and the outer ridge 41 is provided on the resin outer plate 33.

  Therefore, it is possible to prevent the outer protrusion 41 from damaging the placement surface 81 while ensuring the rigidity of the inner protrusion 37.

As a result, the inner ridge 37 can be protected, and the mounting surface 81 can also be protected.
(9) According to this color printer 1, as shown in FIG. 10, the process unit 9 is placed on the placement surface 81 so as to be inclined relative to the state where it is attached to the main casing 2.

  Therefore, with a simple configuration, each photosensitive drum 14 can be separated upward from the placement surface 81 so as not to contact the placement surface 81, and each photosensitive drum 14 can be protected.

  Further, when the process unit 9 is placed on the placement surface 81, the process unit 9 is inclined so that the rear end is lifted upward as compared with the state where the process unit 9 is mounted in the main body casing 2.

  Accordingly, the toner L in the developing cartridge 13 has a level L2 (a level when the toner is placed on the placement surface 81) inclined with respect to the level L1 when the toner is mounted in the main body casing 2. Can be moved.

Therefore, the toner in the developing cartridge 13 can be placed only by placing the process unit 9 on the placement surface 81, and the fluidity of the toner can be ensured.
8). Modified Example A modified example of the color printer 1 will be described with reference to FIGS. In each modification, the same reference numerals are given to the same members as those in the above-described embodiment, and the description thereof is omitted.

  In the above-described embodiment, the second reference shaft 53 is formed in a substantially cylindrical shape extending in the left-right direction, but the second reference shaft 53 is, for example, a substantially cylindrical shape extending in the left-right direction, as shown in FIG. As shown in FIG. 12, it can also be formed in a substantially U-shaped cross section that extends in the left-right direction and opens downward. The concave portion 42 of the outer ridge 37 can be formed so as to correspond to the shape of the second reference shaft 53. Specifically, the concave portion 42 of the outer ridge 37 is formed such that the lower end edge of the outer ridge 37 does not contact the second reference shaft 53 and the lower end edge of the inner ridge 37 contacts the second reference shaft 53. Is formed.

  In the embodiment described above, the front beam 34 is provided with the insertion shaft 61 so as to protrude outward in the left-right direction from the outer plate 33 at both left and right end portions (projecting portions 43). The pressing arm 58 of the pressing mechanism 56 presses the protrusion 43.

  However, as shown in FIG. 13, for example, a pressing member 91 protruding forward from the front end portion is formed on the outer plate 33 of the both side plates 44, and a pressing member provided on the front cover 5 via a compression spring 92. 93, the pressed portion 91 can also be pressed to the rear lower side so that a component force is generated on the rear side and the lower side.

  The pressed portion 91 is formed in a substantially rectangular shape in a side view extending from the front end edges of the outer side plates 33 to the front upper side, and the front end surface extends in a direction connecting the rear upper side and the front lower side.

  The pressing member 93 extends in a direction connecting the rear lower side and the front upper side in a state in which the pressing member 93 is in contact with the pressed portion 91, and the rear lower end that is in contact with the pressed portion 91 has a substantially semicircular cross section. Is formed. A compression spring 92 is interposed between the front upper end of the pressing member 93 and the rear surface of the front cover 5.

  Also in this modified example, the inner peripheral edges of both inner notches 38 are pressed against the first positioning portion 71 to position the front end portion of the process unit 9 with respect to the first reference shaft 52, and at the same time, the lower ends of both inner protrusions 37 The edge can be pressed against the second positioning portion 72 to position the rear end portion of the process unit 9 with respect to the second reference shaft 53.

  As a result, the front end portion and the rear end portion of the process unit 9 can be simultaneously positioned with a simple configuration.

  Further, in the above-described embodiment, each pressing mechanism 56 is interlocked with the front cover 5 via an interlocking mechanism (not shown), and interlocked with the opening operation of the front cover 5, and the protruding portion 43 of the pressing arm 58. It is also possible to configure so that the protrusion 43 is pressed by the pressing arm 58 in conjunction with the closing operation of the front cover 5 by releasing the pressing against the front cover 5.

  Also in each of these modified examples, it is possible to obtain the same effects as the above-described embodiment.

DESCRIPTION OF SYMBOLS 1 Color printer 2 Main body casing 7 Registration roller 9 Process unit 10 Transfer unit 14 Photosensitive drum 20 Drive roller 21 Driven roller 22 Conveyor belt 32 Inner plate 34 Front beam 37 Inner protrusion 38 Inner notch 43 Projection 44 Side plate 51 Side wall 52 First 1 reference shaft 53 second reference shaft 58 pressing arm 61 insertion shaft 71 first positioning portion 72 second positioning portion 81 placing surface 93 pressing member

Claims (3)

A photosensitive unit that is detachably attached to an apparatus main body of an image forming apparatus,
The photoconductor unit includes a pair of side plates arranged to face each other at intervals in the longitudinal direction of a plurality of photoconductors arranged in parallel at intervals.
Both side plates are
In the mounting direction of the photoconductor unit, it is provided at the peripheral edge of the side plate on the upstream side in the mounting direction, and abuts against a predetermined portion in the apparatus main body when the photoconductor unit is mounted on the apparatus main body. A contact portion,
Aside from the abutting portion, the side plate is provided at a peripheral portion on the upstream side in the mounting direction, and is mounted when the photosensitive unit is detached from the apparatus main body and placed on a predetermined placement surface. And a contact portion that is in contact with the surface. The contact portion is made of metal,
The photoconductor unit according to claim 1, wherein the contact portion is made of a resin.   The photoconductor unit according to claim 1, wherein the photoconductor unit is mounted on the mounting surface so as to be inclined with respect to a state in which the apparatus is mounted on the apparatus main body.

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