JP5699631B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as an electrophotographic color printer.

  As an image forming apparatus, a tandem type photoreceptor unit that integrally holds a plurality of photoreceptors arranged in parallel in a predetermined direction, and a plurality of developer cartridges having a developer carrier that supplies developer to the corresponding photoreceptor A color laser printer is known. The tandem photoconductor unit is slidable between a drawing position and a mounting position with respect to the image forming apparatus main body. Each developing cartridge can be attached to and detached from the tandem photoconductor unit when the tandem photoconductor unit is in the drawing position.

  Patent Document 1 proposes an easy-to-use color laser printer that does not require the user to pay attention to whether each developing cartridge is completely attached to the tandem type photoreceptor unit. That is, each developing cartridge is attached to the tandem photoconductor unit, and the first posture is pressed by the pressing portion provided in the tandem photoconductor unit, and the pressing of the pressing portion is released and the tandem photoconductor is released. The posture can be changed by rotating to a second posture that can be detached from the body unit. When the tandem type photosensitive unit is mounted on the image forming apparatus main body, the developing cartridge in the second attitude comes into contact with the abutting portion provided on the image forming apparatus main body so that the first attitude of the cartridge is changed. Can change to posture.

JP 2010-128336 A

  However, the contact portion of Patent Document 1 contacts the developing cartridge on a surface orthogonal to the mounting direction of the tandem photosensitive unit. Therefore, the rotation distance between the second posture and the first posture is such that the developing cartridge whose posture has been changed from the second posture to the first posture when the tandem photosensitive unit is mounted passes under the contact portion. Need to be larger. In this case, since it is necessary to increase the distance in the mounting direction and the vertical direction, there is a problem that the apparatus becomes large.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus in which the apparatus main body does not increase in size even if the tandem type photosensitive unit on which the developing cartridge is detachably mounted can be pulled out from the image forming apparatus main body even if the usability is improved. Is to provide.

  In order to achieve this object, an image forming apparatus according to claim 1 includes a main body casing having a first wall and a second wall, and a tandem type photosensitive member configured to be drawn in a predetermined direction with respect to the main body casing. A body unit and a plurality of developing cartridges that are detachable from the tandem photosensitive unit, and the main body casing has a first sliding contact portion including a first sliding contact surface, and the tandem type The photoconductor unit includes a plurality of photoconductors arranged in parallel in the predetermined direction and a plurality of pressing members, and each of the developing cartridges carries a developer to be supplied to the corresponding photoconductor. The main body casing is mounted with a carrier, a pressed portion that is pressed by the corresponding pressing member, and the tandem photoconductor unit so that the developer carrier is directed to the corresponding photoconductor. A second slidable contact portion including a second slidable contact surface facing the first slidable contact surface in the rotational axis direction of the photosensitive member, and the developing cartridge is a tandem type photosensitive member unit. The pressing position where the pressed part is pressed by the pressing part when the pressed part is engaged with the pressing part, and the pressing of the pressing part against the pressed part is released when the pressed part is detached from the pressing part. And the detachment position where the tandem type photosensitive member unit can be detached from the tandem type photosensitive member unit, and the development is in the detachable position when the tandem type photosensitive member unit is attached to the main body casing. The cartridge is characterized in that the cartridge is rotated to the pressing position when the first sliding contact surface of the first sliding contact portion comes into sliding contact with the second sliding contact surface of the second sliding contact portion.

The first wall is disposed with a space between the first wall and the second wall in the rotation axis direction, and the first sliding contact surface is provided on the first wall side in the first sliding contact portion. In the mounting direction of the tandem photoconductor unit, gradually approaches the first wall side from the upstream end of the first sliding contact surface toward the downstream end of the first sliding contact surface,
The second slidable contact surface is provided on the second wall side in the second slidable contact portion, and the second slidable contact surface from the upstream end of the second slidable contact surface in the mounting direction of the tandem type photoreceptor unit. It is characterized by gradually approaching the first wall side toward the downstream end of the surface.

The image forming apparatus according to claim 2 , wherein the first sliding contact portion has a third sliding contact surface, and the second sliding contact portion is configured such that the tandem photosensitive unit is pulled out from the main body casing. On the way, the developing cartridge has a fourth sliding contact surface that faces the third sliding contact surface in the rotation axis direction of the photosensitive member, and the developing cartridge is configured such that when the tandem photosensitive member unit is pulled out from the main body casing, When the third slidable contact surface and the fourth slidable contact surface are in slidable contact with each other, the third slidable contact surface rotates from the pressed position to the disengaged position.

The third sliding contact surface of the image forming apparatus according to claim 3 is provided on the first wall side in the first sliding contact portion in the mounting direction of the tandem type photosensitive unit, the third sliding As it goes from the upstream end of the contact surface toward the downstream end of the third slidable contact surface, it gradually moves away from the first wall side, and the fourth slidable contact surface moves toward the second wall side at the second slidable contact portion. In the mounting direction of the tandem photoconductor unit, the distance from the first wall side gradually increases from the upstream end of the fourth sliding contact surface toward the downstream end of the fourth sliding contact surface. To do.

Further, a downstream end of the first sliding contact surface of the image forming apparatus according to claim 4 coincides with an upstream end of the third sliding contact surface in the mounting direction of the tandem photosensitive unit, and The upstream end of the sliding contact surface is coincident with the downstream end of the fourth sliding contact surface in the mounting direction of the tandem photoconductor unit.

The main body casing of the image forming apparatus according to claim 5 is provided on an upstream side in the mounting direction of the tandem photoconductor unit, and the tandem photoconductor unit is separated from the first wall with respect to the main body casing. It has the 1st offset member biased in the direction which goes to the said 2nd sliding wall, It is characterized by the above-mentioned.

Further, in the image forming apparatus according to claim 6 , the developing cartridge is a second offset that shifts the developing cartridge toward the second wall from the first wall with respect to the tandem photosensitive unit. It has the member.

  In the image forming apparatus according to claim 1, the developing cartridge at the disengagement position when the tandem type photosensitive unit is attached to the main body casing is provided in the first sliding contact portion provided in the main body casing and the developing cartridge. By the sliding contact with the second sliding contact portion, it is rotated to the pressing position. Therefore, even if the user forgets to turn the developing cartridge from the disengaged position to the pressed position when the developing cartridge is mounted on the tandem photosensitive unit, the developing operation is performed by mounting the tandem photosensitive unit on the main casing. Since the cartridge is changed to the pressing position, it is possible to reliably form an image in a state where all the developing cartridges of the tandem type photosensitive unit are in the pressing position. As a result, in a configuration in which the tandem photosensitive unit to which the developing cartridge is detachably mounted is movable with respect to the main body casing, usability can be improved.

  Further, the first sliding contact surface of the first sliding contact portion provided in the main body casing and the second sliding contact surface of the second sliding contact portion provided in the developing cartridge face each other in the rotation axis direction of the photosensitive member. Therefore, even if the developing cartridge in the detached position rotates to the pressing position during the mounting operation of the tandem photosensitive unit, the second sliding contact portion of the developing cartridge can pass to the side of the first sliding contact portion of the main body casing. It is. As a result, the rotational distance between the pressing position and the separation position can be reduced, so that the dimension in the mounting direction of the tandem type photoreceptor unit in the image forming apparatus can be reduced.

Moreover , the 1st slidable contact surface and 2nd slidable contact surface which oppose are inclined with respect to the mounting direction. Accordingly, when the tandem type photosensitive unit is mounted, the first sliding contact surface and the second sliding contact surface can be slidably contacted even if the positioning of the developing cartridge in the rotational axis direction of the photosensitive drum is not accurate. It is possible to have a width that can be achieved.

In the image forming apparatus according to claim 2, the third sliding surface is provided on the first sliding contact portion of the main body casing, the fourth sliding surface is provided on the second sliding contact portion of the developing cartridge. The third slidable contact surface and the fourth slidable contact surface are disposed at positions that face each other when the tandem photosensitive unit is pulled out from the main body casing. Therefore, when the tandem photoconductor unit is pulled out from the main body casing, the developing cartridge in the pressing position rotates to the separation position by the sliding contact between the third sliding contact surface and the fourth sliding contact surface. That is, when exchanging the developing cartridge, the user does not need to rotate the developing cartridge from the pressing position to the releasing position. As a result, it is possible to improve the usability in the configuration in which the developing cartridge can be rotated with respect to the tandem photosensitive member unit at the pressing position and the separating position.

In the image forming apparatus according to claim 3, wherein the third sliding surface and the fourth sliding surface faces are inclined with respect to the mounting direction. As a result, when the tandem photoconductor unit is pulled out, the third sliding contact surface and the fourth sliding contact surface can be reliably brought into sliding contact, and the developing cartridge at the pressing position can be reliably moved to the release position. it can.

5. The image forming apparatus according to claim 4 , wherein the downstream end of the first slidable contact surface coincides with the upstream end of the third slidable contact surface in the mounting direction of the tandem photosensitive unit, and the downstream end of the second slidable contact surface. And the upstream end of the fourth sliding contact surface coincide with each other. Thereby, the length of the first sliding contact portion and the second sliding contact portion in the mounting direction of the tandem photoconductor unit can be reduced, and the arrangement position of the first sliding contact portion and the second sliding contact portion is limited. The number of design freedom increases.

According to a fifth aspect of the present invention, the image forming apparatus includes a first offset member that shifts the tandem type photosensitive unit with respect to the main body casing in a direction from one to the other in the rotation axis direction of the photosensitive member. As a result, the second sliding contact surface is reliably pressed against the first sliding contact surface, so that the developing cartridge can be reliably rotated from the disengagement position to the pressing position.

According to a sixth aspect of the present invention, the image forming apparatus further includes a second offset member that shifts the developing cartridge relative to the tandem type photosensitive unit in a direction from one side to the other side in the rotation axis direction of the photosensitive member. As a result, the second sliding contact surface is reliably pressed against the first sliding contact surface, so that the developing cartridge can be reliably rotated from the disengagement position to the pressing position.

It is a sectional side view showing one embodiment of a printer. It is a perspective view of a process unit. It is a top view of a process unit. Of the process unit, the front beam is removed. It is a perspective view of a main body casing. It is a figure where a process unit is located in a drawer position with respect to a main part casing. It is a figure where a process unit is located in a mounting position with respect to a main part casing. It is a figure which shows the middle of mounting | wearing a process unit with a main body casing. It is a figure which shows the middle of mounting | wearing a process unit with a main body casing. It is a figure which shows the state which the 1st offset member is pressing the process unit. It is a figure which shows the middle of mounting | wearing a process unit with a main body casing (modification).

1. Overall Configuration of Printer FIG. 1 is a side sectional view showing an embodiment of a printer 1 as an example of an image forming apparatus of the present invention. The left side of the paper is the front side of the printer 1, the right side of the paper is the rear side of the printer 1, and the time when the printer 1 is viewed from the front side is the left and right reference of the printer 1. Each figure includes arrows indicating front, rear, up, down, left and right directions.

  The printer 1 is a tandem type color printer. A process unit 3 is accommodated in the main casing 2. The process unit 3 is slidable between a mounting position where the image can be formed on the main body casing 2 and a drawing position where the process unit 3 is pulled out from the main body casing 2.

  The process unit 3 includes a tandem photoreceptor unit 4 and a plurality of developing cartridges 5 that are detachably attached to the tandem photoreceptor unit 4.

  The tandem photoreceptor unit 4 includes a photoreceptor drum 12 as an example of a photoreceptor, a scorotron charger 13, a drum cleaning roller 14, and a photoreceptor frame 15. Four photosensitive drums 12 are arranged in parallel at intervals in the front-rear direction so as to extend in the left-right direction. Specifically, a black photosensitive drum 12K, a yellow photosensitive drum 12Y, a magenta photosensitive drum 12M, and a cyan photosensitive drum 12C are sequentially arranged from the front side to the rear side. The scorotron charger 13 is disposed on the upper side obliquely rearward of the photosensitive drum 12 so as to face the photosensitive drum 12 with a gap. The drum cleaning roller 14 is disposed on the rear side of the photosensitive drum 12 so as to face and contact the photosensitive drum 12. The photoreceptor frame 15 holds the photosensitive drum 12, the scorotron charger 13, and the drum cleaning roller 14.

  The developing cartridge 5 includes a developing frame 16, a developing roller 17, a supply roller 18, and a layer thickness regulating blade 19. Each developing cartridge 5 is detachably supported on the photosensitive frame 15 above the photosensitive drum 12 so as to correspond to each photosensitive drum 12. Specifically, a black developing cartridge 5K, a yellow developing cartridge 5Y, a magenta developing cartridge 5M, and a cyan developing cartridge 5C are sequentially supported from the front side to the rear side.

  The surface of the photosensitive drum 12 is uniformly charged by the scorotron charger 13 and then selectively exposed by the laser beam emitted from the scanner unit 6. Thereby, an electrostatic latent image based on the image data is formed on the surface of each photosensitive drum 12. Each electrostatic latent image is visualized by toner carried on the developing roller 17, and a toner image is formed on the surface of the photosensitive drum 12.

The paper P is accommodated in a paper feed cassette 7 arranged at the bottom of the main casing 2.
The paper P stored in the paper feed cassette 7 is transported onto the transport belt 8 by various rollers. The conveyor belt 8 is disposed to face the four photosensitive drums 12 from below. The paper P transported on the transport belt 8 sequentially passes between the transport belt 8 and each photosensitive drum 12 as the transport belt 8 travels. The toner image on the surface of the photosensitive drum 12 is transferred onto the paper P by the transfer bias applied to the transfer roller 9 when facing the paper P. The transfer roller 9 is disposed to face each photosensitive drum 12 with the conveyance belt 8 interposed therebetween.

  The sheet P on which the toner image is transferred is conveyed to the fixing unit 10. The toner image transferred onto the paper P is thermally fixed by the fixing unit 10. Thereafter, the paper P is discharged to the paper discharge tray 11 by various rollers.

2. Details of Process Unit FIG. 2 is a perspective view of the process unit 3. FIG. 3 is a plan view of the process unit 3. FIG. 4 is a view of the process unit 3 from which the front beam 20 is removed as viewed from the front side. In addition, the arrow of FIG. 3 has shown the attachment direction to the main body casing 2 of the process unit 3. As shown in FIG.

  As described above, the process unit 3 includes the tandem photoconductor unit 4 and the developing cartridge 5. The process unit 3 is slidable along the substantially horizontal direction (front-rear direction) with respect to the main body casing 2. A detailed description of the slide movement will be described later.

(1) Tandem type photoconductor unit The photoconductor frame 15 of the tandem type photoconductor unit 4 is formed in a substantially rectangular frame shape when viewed from above in the front-rear direction, and includes a front beam 20, a rear beam 21, and a pair of left and right. The side plate 22 is integrally provided.

  The front beam 20 is installed between the front ends of the side plates 22. A front handle 23 is provided at the center of the front surface of the front beam 20 in the left-right direction. The front beam 20 is inserted with a positioning shaft 24 extending in the left-right direction, and both end portions in the left-right direction of the positioning shaft 24 pass through the front end portions of the side plates 22 and protrude outward in the left-right direction. The rear beam 21 is installed between the rear ends of the side plates 22. A rear handle 25 is provided at the center of the upper end of the rear beam 21 in the left-right direction. The both side plates 22 are arranged to face each other with a gap in the left-right direction. The both side plates 22 extend substantially vertically and are formed in a substantially rectangular shape that is long in the front-rear direction.

  The tandem type photoreceptor unit 4 includes a pressing cam 26 as an example of a pressing member that is provided above both side plates 22 and that presses each developing cartridge 5 in a direction in which the developing roller 17 faces the photosensitive drum 12.

  The pressing cam 26 is provided at a position that coincides with both left and right ends of each developing cartridge 5 and has a substantially fan shape when viewed from the left and right (see FIG. 8A). The pressing cam 26 is connected to a pair of upper and lower plane portions 28 that are spaced apart from each other toward the upper rear side, and a curved surface portion 29 that connects the rear upper ends of both plane portions 28 and bulges substantially rearwardly to the rear upper side. Are integrated. The pressing cam 26 has a rotating shaft 30 extending outward in the left-right direction in the vicinity of the connecting portion between the front lower ends of the two flat surface portions 28. The rotating shaft 30 is supported on the inner side surface of the corresponding side plate 22 in the left-right direction. Thereby, the pressing cam 26 is rotatable about the rotation shaft 30.

  The pressing cam 26 is always urged clockwise by a right side view by an urging member (not shown). As a result, the pressing cam 26 is always tilted rearward by a biasing force of a biasing member (not shown), and is raised and moved by rotating against a biasing force of a biasing member (not shown). To do.

(2) Developing Cartridge The developing cartridge 5 includes the developing frame 16 that holds the developing roller 17, the supply roller 18, and the layer thickness regulating blade 19 inside as described above.

  The developing frame 16 is formed in a substantially box shape that is long in the left-right direction. The developing frame 16 rotatably supports both ends of the developing roller 17 in the left-right direction. The developing frame 16 includes a pair of left and right bosses 31 as an example of a pressed portion, a handle 32, a second sliding contact portion 33, and a second offset member 34. The boss 31 is formed in a substantially cylindrical shape that protrudes outward in the left-right direction at the front upper ends of the left and right end faces of the developing frame 16. The handle 32 is formed so as to extend in the left-right direction at the center in the left-right direction of the front upper end of the developing frame 16.

  The second sliding contact portion 33 is made of polystyrene. The second sliding contact portion 33 extends upward from the upper end portion of the developing frame 16 on the left side in the left-right direction of the upper end portion of the developing frame 16. The upper end portion of the second sliding contact portion 33 is a position that does not come into contact with an upper wall 42 (described later) of the main casing 2 when the developing cartridge 5 is in either the pressing position or the separation position. It is in a position higher than the position of the lower end portion of 48.

  The second sliding contact portion 33 has a substantially pentagonal cross section in the vertical direction, and the front flat surface 33A, the rear flat surface 33B, the side surface 33C, the fourth sliding contact surface 33D, and the second sliding contact surface 33E are integrated. Have. The front plane 33A and the rear plane 33B extend linearly in the left-right direction so that they are substantially parallel to each other. The side surface 33C connects the right ends of the front plane 33A and the rear plane 33B, and extends linearly in the front-rear direction.

  The fourth sliding contact surface 33D connects the left end of the front flat surface 33A and the front end of the second sliding contact surface 33E, extends substantially linearly in the front-rear direction, and gradually approaches the left end of the developing frame 16 from the front end toward the rear end. It is formed to approach the surface.

  The second slidable contact surface 33E connects the left end of the rear flat surface 33B and the rear end of the fourth slidable contact surface 33D, extends substantially linearly in the front-rear direction, and gradually extends from the front end toward the rear end of the developing frame 16. It is formed so as to approach the right side surface.

  The second offset member 34 includes a color member 34 </ b> A covering the shaft of the developing roller 17 and an electrode 34 </ b> B for applying a bias to the developing roller 17. The color member 34A covers the shaft of the developing roller 17 and is covered with a covering portion 34A1 formed of a resin, and is inserted through the shaft of the developing roller 17 and is provided between the covering portion 34A1 and the right side surface of the developing frame 16. And have. The electrode 34B is provided on the right side surface of the developing cartridge 5 and is configured by a leaf spring. The coil spring 34A2 of the color member 34A and the leaf spring of the electrode 34B have a natural length when the developing cartridge 5 is taken out from the tandem type photoreceptor unit 4. When the developing cartridge 5 is attached to the tandem type photoreceptor unit 4, the coil spring 34A2 of the color member 34A and the leaf spring of the electrode 34B come into contact with the side plate 22 of the tandem type photoreceptor unit 4 and are compressed. At that time, the color member 34 </ b> A and the electrode 34 </ b> B receive a reaction force to the left side from the side plate 22 of the tandem type photoreceptor unit 4, and press the developing frame 16 of the developing cartridge 5 to the left side.

3. Details of Main Body Casing FIG. 5 is a perspective view of the main body casing 2 in which the front cover 47 is opened.

The main body casing 2 is formed in a box shape having a substantially rectangular shape in side view. The main body casing 2 has an accommodating portion 50 in which the process unit 3 is accommodated, and an example of a front wall 40, a rear wall 41, an upper wall 42, a bottom wall 43, and a first wall formed so as to surround the accommodating portion 50. As a right side wall 44 and a left side wall 45 as an example of a second wall.
The front wall 40 has an opening 46. The opening 46 is formed for moving the process unit 3 from the mounting position to the drawing position and replacing the developing cartridge 5 mounted on the tandem type photoreceptor unit 4. The opening 46 is covered with a front cover 47. The front cover 47 is provided so as to be able to swing with respect to the main body casing 2 with the lower end portion as a fulcrum, and the opening 46 is exposed by being tilted forward.

  The main casing 2 includes a first offset member 49 provided at the front end portion of the right wall 44 and a first sliding contact portion 48 provided at the front end portion of the upper wall 42.

  The first offset member 49 is formed of a spring. When the process unit 3 is in the pulled out position, the spring has a natural length. When the first offset member 49 comes into contact with the side surface 22 of the process unit 3 as the process unit 3 (tandem type photoreceptor unit 4) moves from the drawing position to the mounting position, the spring is compressed and the process unit 3 is moved to the left side. Press towards.

  The first sliding contact portion 48 is made of polystyrene. The first sliding contact portion 48 protrudes downward from the upper wall 42 and comes into sliding contact with the second sliding contact portion 33 of the developing cartridge 5 when the process unit 3 is mounted. The first sliding contact portion 48 is located on the left side in the left-right direction with respect to the second sliding contact portion 33 when the tandem photoconductor unit 4 moves from the drawing position to the mounting position (see FIG. 3). The lower end portion of the first slidable contact portion 48 is located at a position lower than the upper end portion of the second slidable contact portion 33 when the developing cartridge 5 is in either the pressing position or the release position. The first sliding contact portion 48 has a substantially pentagonal cross section in the vertical direction, and the front flat surface 48A, the rear flat surface 48B, the side surface 48C, the first sliding contact surface 48D, and the third sliding contact surface 48E are integrated. (See FIG. 3).

  The front plane 48A and the rear plane 48B extend linearly in the left-right direction so that they are substantially parallel to each other. The side surface 48C connects the left ends of the front plane 48A and the rear plane 48B, and extends in the front-rear direction. The first sliding contact surface 48D connects the right end of the front flat surface 48A and the front end of the third sliding contact surface 48E, extends substantially linearly in the front-rear direction, and gradually moves to the right side of the developing frame 16 from the front end toward the rear end. It is formed to approach the surface. The first sliding contact surface 48D is formed to be substantially parallel to the second sliding contact surface 33E.

  The third slidable contact surface 48E connects the right end of the rear flat surface 48B and the rear end of the first slidable contact surface 48D, extends substantially linearly in the front-rear direction, and gradually develops the developing frame 16 from the front end toward the rear end. It is formed to approach the left side. The third sliding contact surface 48E is formed so as to be substantially parallel to the fourth sliding contact surface 33D.

4). FIG. 6 is a diagram showing the process unit 3 positioned in the extraction position with respect to the main body casing 2. FIG. 7 is a view in which the process unit 3 is located at the mounting position with respect to the main casing 2. FIG. 8A and FIG. 8B are views showing the process unit 3 being attached to the main casing 2. FIG. 9 is a diagram illustrating a state where the first offset member 49 is pressing the process unit 3. The arrows in FIGS. 8A and 8B indicate the mounting direction of the process unit 3 to the main casing 2.

(1) Attaching / demounting the developing cartridge to / from the photoconductor frame To mount the developing cartridge 5 on the main casing 2, first, the developing cartridge 5 is mounted on the photoconductor frame 15 of the tandem type photoconductor unit 4.
In order to attach the developing cartridge 5 to the photoconductor frame 15, first, the front cover 47 is swung forward to expose the opening 46, and then the tandem type photoconductor unit 4 is pulled out from the main body casing 2 to the front side. Pull out until.
Next, when the developing cartridge 5 is inserted into the photoconductor frame 15 at a position that coincides with the corresponding photosensitive drum 12 in the front-rear direction, the developing cartridge 5 is disposed at the disengagement position (see FIG. 8A). At this time, the boss 31 is in contact with the curved surface portion 29 of the pressing cam 26. That is, the boss 31 is disengaged from the pressing cam 26, and the pressing of the pressing cam 26 against the boss 31 is released. Therefore, the developing cartridge 5 can be detached from the photoconductor frame 15 when it is disposed at the separation position.

  Next, the developing cartridge 5 is rotated forward while the developing cartridge 5 is in the detached position. Then, the developing cartridge 5 is rotated to the front side with the developing roller 17 as the center, and is disposed at the pressing position (see the developing cartridge 5C in FIG. 8B). At this time, the boss 31 presses the lower end portion of the curved surface portion 29 of the pressing cam 26 toward the front upper side. Then, the pressing cam 26 rotates to the front upper side and moves. At this time, the boss 31 contacts the flat portion 28 of the pressing cam 26.

As a result, the developing cartridge 5 is moved from the disengaged position to the pressing position and is pressed by the pressing cam 26, so that the developing cartridge 5 is completely attached to the photoconductor frame 15.
Note that when the developing cartridge 5 is detached from the photoconductor frame 15, the operation is performed in the reverse procedure to that when the developing cartridge 5 is mounted on the photoconductor frame 15.

(2) Attaching the Process Unit to the Main Body Casing Next, the process unit 3 (tandem photoconductor unit 4 with all the developing cartridges 5 attached) is attached to the main body casing 2. In order to slide the process unit 3 from the pull-out position to the mounting position with respect to the main body casing 2, the process unit 3 is inserted into the main body casing 2 toward the rear side.

  When the process unit 3 is pushed rearward, the process unit 3 is inserted into the main body casing 2 toward the rear side in a substantially horizontal direction so as not to contact the conveyance belt 8.

  At this time, the developing cartridge 5 may not be disposed at the pressing position, and the developing cartridge 5 may be disposed at the detached position.

  In this case, when the process unit 3 is inserted into the main casing 2, the second sliding contact portion 33 of the developing cartridge 5 contacts the first sliding contact portion 48 of the main casing 2. It is rotated toward the front side and moved from the disengagement position to the pressing position.

  Specifically, first, the second sliding contact surface 33E of the second sliding contact portion 33 of the developing cartridge 5 is in sliding contact with the first sliding contact surface 48D of the first sliding contact portion 48 of the main casing 2 from the front side (FIG. 3). The second sliding contact surface 33E and the first sliding contact surface 48D extend substantially in parallel so as to gradually approach the right side wall 44 from the front side toward the rear side. Therefore, even if there is variation in the horizontal dimension of the developing cartridge 5 due to tolerances, when the process unit 3 is slid, the first sliding contact surface 48D and the second sliding contact surface 33E come into sliding contact. . The first slidable contact surface 48D and the second slidable contact surface 33E are in slidable contact with each other, so that a frictional force directed in the direction opposite to the mounting direction of the process unit 3 is generated. When the frictional force becomes equal to or greater than the rotational force required when the developing cartridge 5 is rotated from the detached position to the pressing position, the developing cartridge 5 is rotated toward the front side and moved from the separating position to the pressing position. It moves (see the developing cartridge 5C in FIG. 8B).

  In this way, when the second sliding contact portions 33 of all the developing cartridges 5 are in sliding contact with the first sliding contact portions 48 of the main body casing 2, all the developing cartridges 5 are positioned at the pressing positions, and image formation is possible. It becomes.

  Further, when the developing cartridge 5 is mounted on the tandem type photoreceptor unit 4, the second offset member 34 presses the developing cartridge 5 to the left side. Further, when the process unit 3 is mounted on the main casing 2, the first offset member 49 of the main casing 2 presses the tandem photosensitive pair unit 4 to the left.

  In this way, the process unit 3 is slid to the mounting position, and the mounting of the process unit 3 on the main body casing 2 is completed.

(3) Pulling out the process unit from the main body casing When the process unit 3 attached to the main body casing 2 is slid to the pulling position with respect to the main body casing 2, the front cover 47 is swung forward to open the opening 46. Then, the process unit 3 is pulled out to the front side.
When the process unit 3 is taken out of the main casing 2, the second sliding contact portion 33 of the developing cartridge 5 comes into sliding contact with the first sliding contact portion 48 of the main casing 2. As a result, the developing cartridge 5 is rotated toward the rear side and moved from the pressing position to the separation position.

  Specifically, first, the fourth sliding contact surface 33D of the second sliding contact portion 33 of the developing cartridge 5 is in sliding contact with the third sliding contact surface 48E of the first sliding contact portion 48 from the rear side (see FIG. 3). . The third slidable contact surface 48E and the fourth slidable contact surface 33D gradually move away from the right side wall 44 from the front side toward the rear side, in other words, gradually approach the right side wall 44 from the rear side toward the front side. Extending substantially parallel to the. Therefore, even if there is variation in the horizontal dimension of the developing cartridge 5 due to tolerances, when the process unit 3 is slid, the third sliding contact surface 48E and the fourth sliding contact surface 33D come into sliding contact. . When the third sliding contact surface 48E and the fourth sliding contact surface 33D are in sliding contact, a frictional force directed in the direction opposite to the drawing direction of the process unit 3 is generated. When the frictional force becomes equal to or greater than the rotational force required to rotate the developer cartridge 5 from the pressed position to the detached position, the developer cartridge 5 is rotated toward the rear side to move from the pressed position to the detached position. (See the developing cartridge 5C in FIG. 8A).

In this way, when the second slidable contact portions 33 of all the developing cartridges 5 are in contact with the first slidable contact portion 48 of the main body casing 2 and the process unit 3 is completely pulled out from the main body casing 2, all the developing operations are performed. The cartridge 5 is located at the disengagement position, and the process unit 3 is disposed at the withdrawal position with respect to the main body casing 2.
As described above, the first sliding contact portion 48 includes the first sliding contact surface 48D and the third sliding contact surface 48E, and the second sliding contact portion 33 includes the second sliding contact surface 33E and the fourth sliding contact surface. By providing 33D, the developing cartridge 5 can be moved in both the detachment position and the pressing position only by the first sliding contact portion 48 and the second sliding contact portion 33.

5. Operational Effects (1) As described above, the printer 1 includes the process unit 3 that is slidable along the front-rear direction with respect to the main body casing 2 as shown in FIGS.
The process unit 3 includes a tandem photoconductor unit 4 and a developing cartridge 5 that is detachable from the tandem photoconductor unit 4.
The developing cartridge 5 can be detached from the tandem photoconductor unit 4 when the tandem photoconductor unit 4 is pressed against the flat portion 28 of the pressing cam 26 and the flat portion 28 is released. (See the developing cartridge 5C in FIG. 8). When the developing cartridge 5 is in the pressing position, the developing roller 17 can be pressed against the corresponding photosensitive drum 12, so that toner is smoothly supplied to the photosensitive drum 12 to develop the electrostatic latent image on the photosensitive drum 12. Good image formation can be achieved.

  When the developing cartridge 5 is attached to the tandem type photoreceptor unit 4, the developing cartridge 5 is first in the disengaged position and then rotated to the pressing position, thereby being completely attached to the tandem type photoreceptor unit 4. The When the developing cartridge 5 remains in the disengaged position, the developing cartridge 5 is not completely attached to the tandem type photoreceptor unit 4, and the developing roller 17 cannot smoothly supply toner to the photosensitive drum 12, and a good image can be obtained. Formation is difficult.

Therefore, as shown in FIG. 1, it is necessary that all the developing cartridges 5 are in the pressing position in a state where the process unit 3 is mounted on the main casing 2. However, when the developer cartridge 5 is attached to the tandem type photoreceptor unit 4 for the user,
It is inconvenient to check whether the developing cartridge 5 is in the pressed position. That is, if the user always asks the user to change the developing cartridge 5 to the pressed position when the developing cartridge 5 is in the detached position, if the user forgets this operation, the process is performed with the developing cartridge 5 in the detached position. The unit 3 may be attached to the main casing 2.

  Therefore, as shown in FIG. 1, the main casing 2 is provided with a first sliding contact portion 48 having a first sliding contact surface 48D, and the developing cartridge 5 has a second sliding contact surface 33E. A contact portion 33 is provided. When the process unit 3 is mounted on the main casing 2, the first slidable contact surface 48 </ b> D is slidably contacted with the second slidable contact surface 33 </ b> E of the developing cartridge 5 at the disengaged position, thereby changing the developing cartridge 5 to the pressing position. . Therefore, when the process unit 3 is attached to the main body casing 2 without requiring the user to perform the above-described operation, the developing cartridge 5 that has been in the removal position in the process unit 3 is automatically changed to the pressing position. Thus, it is possible to reliably form an image in a state where all the developing cartridges 3 are in the pressed position.

  As a result, in the configuration in which the process unit 3 to which the developing cartridge 5 is detachably mounted is slidable with respect to the main body casing 2, the usability can be improved.

  As shown in FIG. 3, the first slidable contact surface 48 </ b> D and the second slidable contact surface 33 </ b> E face each other in the left-right direction that is the rotational axis direction of the photosensitive drum 12. Therefore, the position of the uppermost end of the second sliding contact portion 33 can be disposed at a position higher than the lowermost end of the first sliding contact portion 48 as shown in FIG. The second sliding contact portion 33 can pass to the right side of the first sliding contact portion 48 when the process unit 3 is mounted on the main casing 2.

  As a result, since the rotation distance between the pressing position and the separation position in the developing cartridge 5 can be reduced, the size of the printer 1 in the mounting direction of the process unit 3 can be reduced.

  (2) The first slidable contact surface 48D is provided on the right side in the first slidable contact portion 48, and is inclined with respect to the front-rear direction so as to gradually approach the right side wall 44 from the front end toward the rear end. The second slidable contact surface 33E is provided on the left side in the second slidable contact portion 33, and is inclined with respect to the front-rear direction so as to gradually approach the right side wall 44 from the front end toward the rear end (see FIG. 3). ). That is, a width in which the first sliding contact surface 48D and the second sliding contact surface 33E interfere with each other in the left-right direction is provided.

  Therefore, when the process unit 3 is mounted on the main casing 2, the second sliding contact surface 33 </ b> E can be reliably brought into sliding contact with the first sliding contact surface 48 </ b> D, and the developing cartridge 5 in the detached position can be reliably pressed. Can be moved to.

  (3) The first sliding contact portion 48 is provided with a third sliding contact surface 48E, and the second sliding contact portion 33 is provided with a fourth sliding contact surface 33D. The third sliding contact surface 48E is in sliding contact with the fourth sliding contact surface 33D when the process unit 3 is pulled out from the main body casing 2 (see FIG. 3). Moreover, the position of the uppermost end of the 2nd sliding contact part 33 is arrange | positioned in the position higher than the lowest end of the 1st sliding contact part 48 (refer FIG. 8). Then, the developing cartridge 5 in the pressing position moves to the separation position. This eliminates the need for the user to rotate the developing cartridge 5 from the pressed position to the detached position.

  As a result, it is possible to improve the usability in the configuration in which the developing cartridge 5 can be rotated with respect to the tandem type photoreceptor unit 4 at the pressing position and the separating position.

  (4) The third slidable contact surface 48E is provided on the right side in the first slidable contact portion 48, and is inclined with respect to the front-rear direction so as to gradually move away from the right side wall 44 from the front end toward the rear end. The fourth sliding contact surface 33D is provided on the left side in the second sliding contact portion 33, and is inclined with respect to the front-rear direction so as to gradually move away from the right wall 44 from the front end toward the rear end (see FIG. 3). ). That is, a width in which the third sliding contact surface 48E and the fourth sliding contact surface 33D interfere with each other in the left-right direction is provided.

  Therefore, when the process unit 3 is pulled out from the main casing 2, the fourth sliding contact surface 33 </ b> D can be surely brought into sliding contact with the third sliding contact surface 48 </ b> E, and the developing cartridge 5 in the pressing position can be reliably moved to the release position. Can be moved.

(5) The rear end of the first sliding contact surface 48D coincides with the front end of the third sliding contact surface 48E, and the rear end of the second sliding contact surface 33E coincides with the front end of the fourth sliding contact surface 33D. . (See Figure 3)
Therefore, the length of the first sliding contact portion 48 and the second sliding contact portion 33 in the mounting direction of the process unit 3 can be shortened, and the installation location and shape of the first sliding contact portion 48 and the second sliding contact portion 33 can be reduced. The degree of freedom increases.

  (6) A first offset member 49 is provided on the right side wall 44 of the main casing 2 (see FIG. 9). The first offset member 49 is provided at the front end portion of the right side wall 44. The first offset member 49 is formed of a spring and presses the tandem type photoreceptor unit 4 to the left as the process unit 3 moves from the drawing position to the mounting position.

  Therefore, the second slidable contact surface 33E facing the left side can be reliably pressed against the first slidable contact surface 48D facing the right side, and when the process unit 3 is mounted, the developing cartridge 5 in the detached position is surely pressed. Can be rotated.

  (7) The developing cartridge 5 includes a second offset member 34 including a color member 34A and an electrode 34B (see FIG. 4). The color member 34A and the electrode 34B press the developing cartridge 5 in the direction from right to left.

  Therefore, the second slidable contact surface 33E facing the left side can be reliably pressed against the first slidable contact surface 48D facing the right side, and when the process unit 3 is mounted, the developing cartridge 5 in the detached position is surely pressed. Can be rotated.

  In addition, by tilting the developing cartridge 5 and the tandem photosensitive unit 4 to the left, the inclination angle of the first sliding contact surface 48D and the second sliding contact surface 33E with respect to the front-rear direction can be reduced. This is because even if the inclination angle is small, the first sliding contact surface 48D and the second sliding contact surface 33E are surely in sliding contact. Further, if the left and right positioning of the developing cartridge 5 and the tandem photoconductor unit 4 during the mounting of the process unit 3 is performed reliably, the inclination angle of the first sliding contact surface 48D and the second sliding contact surface 33E with respect to the front-rear direction can be increased. It may be zero. If the inclination angle of the first sliding contact surface 48D and the second sliding contact surface 33E with respect to the front-rear direction is small, the amount of lateral movement required when the developing cartridge 5 moves from the disengagement position to the pressing position can be reduced. it can.

6). Other Embodiments In the present embodiment, the lower end portion of the first sliding contact portion 48 is positioned lower than the upper end portion of the second sliding contact portion 33 when the developing cartridge 5 is in either the pressing position or the release position. The first sliding contact portion 48 and the second sliding contact portion 33 are in sliding contact even when the developing cartridge 5 is in the pressing position. On the other hand, as shown in FIG. 10, the lower end portion of the first sliding contact portion 48 is lower than the upper end portion of the second sliding contact portion 33 where the developing cartridge 5 is in the detached position, and the developing cartridge 5. May be higher than the upper end of the second sliding contact portion 33 in the pressing position.

  In this case, when the tandem photosensitive unit 4 is moved from the mounting position to the drawing position, the first sliding contact portion 48 and the second sliding contact portion 33 do not come into contact with each other, so that the developing cartridge 5 does not move to the separation position. . When the tandem photosensitive unit 4 in which all the developing cartridges 5 are in the pressing position is moved from the drawing position to the mounting position and when the tandem photosensitive unit 4 is moved from the mounting position to the drawing position, the user is not required. There is no stress.

Further, a cork or felt having a large friction coefficient may be affixed to the first sliding contact surface 48D, the second sliding contact surface 33E, the third sliding contact surface 48E, and the fourth sliding contact surface 33D. The material is not limited to cork or felt, and any material that can generate a frictional force larger than the rotational force for rotating the developing cartridge 5 may be used. Further, the first sliding contact portion 48 and the second sliding contact portion 33 may be formed of cork.
The first offset member 49 and the second offset member 34 are formed of springs, but may be sponge or rubber. Further, the second offset member 34 may be provided in the tandem type photoreceptor unit 4.

DESCRIPTION OF SYMBOLS 1 Printer 2 Main body casing 3 Process unit 4 Tandem type photoconductor unit 5 Developing cartridge 15 Photoconductor frame 16 Developing frame 26 Press cam 33 2nd sliding contact part 33D 4th sliding contact surface 33E 2nd sliding contact surface 34 2nd offset member 48 1st sliding contact part 48D 1st sliding contact surface 48E 3rd sliding contact surface 49 1st offset member

Claims (6)

A main body casing having a first wall and a second wall, a tandem photoconductor unit configured to be able to be pulled out in a predetermined direction with respect to the main body casing, and a plurality of detachable with respect to the tandem photoconductor unit A developing cartridge, and
The main body casing is
A first sliding contact portion including a first sliding contact surface;
The tandem photoreceptor unit is
A plurality of photoconductors arranged in parallel in the predetermined direction;
A plurality of pressing members,
Each of the developing cartridges
A developer carrying member carrying a developer to be supplied to the corresponding photoconductor;
A pressed portion that is pressed by the corresponding pressing member so that the developer carrying member faces the corresponding photosensitive member;
A second slidable contact portion including a second slidable contact surface facing the first slidable contact surface in the rotational axis direction of the photosensitive member in the middle of mounting of the tandem photosensitive member unit on the main body casing. And
The developing cartridge, in the tandem type photosensitive unit, said a pressing position to be pressed against the pressing member by the pressed portion engages with the pressing member, wherein the pressed portion is the pressing member wherein the disengaged position capable withdrawal from the pressing of the pressing member is released by the tandem type photosensitive unit with respect to the pressed portion by departing a between rotatable,
When the tandem photosensitive unit is attached to the main casing, the developing cartridge is in the detached position, and the first sliding surface of the first sliding contact portion is the second sliding contact portion of the second sliding contact portion. By sliding on the contact surface, it rotates to the pressing position ,
The first wall is disposed with a space between the second wall in the rotation axis direction,
The first sliding contact surface is provided on the first wall side in the first sliding contact portion, and the first sliding contact from the upstream end of the first sliding contact surface in the mounting direction of the tandem photosensitive unit. As approaching the downstream end of the surface, gradually approach the first wall side,
The second slidable contact surface is provided on the second wall side in the second slidable contact portion, and the second slidable contact surface from the upstream end of the second slidable contact surface in the mounting direction of the tandem type photoreceptor unit. An image forming apparatus characterized by gradually approaching the first wall side toward a downstream end of the surface . The first sliding contact portion has a third sliding contact surface,
The second slidable contact portion has a fourth slidable contact surface facing the third slidable contact surface in the rotational axis direction of the photosensitive member while the tandem photosensitive member unit is being pulled out from the main body casing.
When the tandem photosensitive unit is pulled out from the main body casing, the developing cartridge is rotated from the pressing position to the disengaged position by the sliding contact between the third sliding contact surface and the fourth sliding contact surface. The image forming apparatus according to claim 1, wherein: The third sliding contact surface is provided on the first wall side in the first sliding contact portion, and the third sliding contact from the upstream end of the third sliding contact surface in the mounting direction of the tandem photosensitive unit. As you go to the downstream end of the surface, gradually move away from the first wall side,
The fourth sliding contact surface is provided on the second wall side in the second sliding contact portion, and the fourth sliding contact surface from the upstream end of the fourth sliding contact surface in the mounting direction of the tandem photosensitive unit. The image forming apparatus according to claim 2 , wherein the image forming apparatus gradually moves away from the first wall side toward a downstream end of the image forming apparatus. The downstream end of the first sliding contact surface coincides with the upstream end of the third sliding contact surface in the mounting direction of the tandem photosensitive unit,
The image forming apparatus according to claim 3 , wherein an upstream end of the second slidable contact surface coincides with a downstream end of the fourth slidable contact surface in the mounting direction of the tandem photosensitive unit. The main body casing is provided on the upstream side in the mounting direction of the tandem photoconductor unit,
And having a first Katayose member biasing the tandem type photosensitive unit from the first wall relative to the main body casing in the direction towards the second wall, any one of claims 1 to 4 1 The image forming apparatus described in the item. The developing cartridge is characterized by having a second Katayose member biasing said developing cartridge from the first wall to the tandem type photosensitive unit in a direction toward the second wall, claim 1 the image forming apparatus according to any one of 5.