JP2014066843A - Process cartridge, developing cartridge, and image forming apparatus - Google Patents

Abstract

To provide a process cartridge and a developing cartridge that can prevent damage to a developer positioning portion and a rotating shaft while ensuring positioning accuracy between a photosensitive member and a developing roller, and an image forming apparatus including them.
[Solution]
In the process cartridge 5, the developing cartridge 7 includes a developing roller 11, a collar 100 provided at an end of the developing roller shaft 28, a right roller shaft cover 114 that covers the collar 100 and has an opening 131, and a drum. The cartridge 6 includes a photosensitive drum 8 and a color clamping portion 49 that positions the developing roller 11 with respect to the photosensitive drum 8 by engaging with the collar 100 through the opening 131.
[Selection] Figure 8

Description

  The present invention relates to an image forming apparatus employing an electrophotographic method, a process cartridge and a developing cartridge mounted on the image forming apparatus.

  As an image forming apparatus, a printer including a cartridge that holds a developing roller and a photosensitive drum is known.

  As a cartridge provided in such a printer, there is a process unit comprising a photosensitive cartridge that holds a photosensitive drum, and a developing cartridge that holds a developing roller facing the photosensitive drum and is detachably provided on the photosensitive cartridge. It has been proposed (see, for example, Patent Document 1).

  In such a process unit, bearing members are provided at both ends of the developing roller shaft, and the bearing members are guided to guide portions formed on the photosensitive cartridge, whereby the developing cartridge is mounted on the photosensitive cartridge, The positioning accuracy of the developing roller with respect to the photosensitive drum is ensured.

JP 2000-250310 A

  However, in the process unit described in Patent Document 1, the bearing bodies provided at both ends of the developing roller shaft protrude from both ends of the developing cartridge in order to guide the developing cartridge to the photosensitive cartridge. There is a case where the cartridge is subjected to an impact due to the dropping of the developing cartridge. As described above, when the bearing body receives an impact, the bearing body itself may be damaged, or the developing roller shaft may be damaged by the impact received by the bearing body, thereby causing problems such as toner leakage from the developing cartridge. .

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a process cartridge and a developing cartridge capable of suppressing damage to the developing side positioning portion and the rotating shaft while ensuring positioning accuracy between the photosensitive member and the developing roller, and an image forming apparatus including them. Is to provide.

(1) In order to achieve the above-described object, a process cartridge of the present invention includes a photoreceptor cartridge and a developing cartridge configured to be attached to the photoreceptor cartridge. And a photosensitive member-side positioning portion provided on the photosensitive member casing. The developing cartridge has a developing case and a rotation shaft, and the rotation shaft is the developing case. A developing roller positioned on the end of the rotating shaft and engaged with the photosensitive member side positioning unit to position the developing roller relative to the photosensitive member, and a developing side positioning unit. And a covering member for covering at an interval.

  The covering member has an opening that opens to the downstream side in the mounting direction of the developing cartridge, and the photoreceptor-side positioning portion is received in the covering member through the opening in a state where the developing cartridge is attached to the photosensitive cartridge. The developing side positioning portion is engaged.

  According to such a configuration, the developing roller has the developing side positioning portion provided at the end of the rotating shaft engaged with the photoconductor side positioning portion provided in the photoconductor housing, thereby preventing the developing roller from being in contact with the photoconductor. Position accurately.

  On the other hand, the development side positioning portion is protected by a covering member having an opening for receiving the photoreceptor side positioning portion.

  Therefore, the covering member can suppress the impact on the developing side positioning portion and the end of the rotating shaft due to the dropping of the developing cartridge or the like.

As a result, it is possible to prevent damage to the developing side positioning portion and the rotating shaft while ensuring the positioning accuracy between the photosensitive member and the developing roller.
(2) In the process cartridge of the present invention, the covering member may not be in contact with the photosensitive member housing in a state where the developing cartridge is mounted on the photosensitive member cartridge.

  According to such a configuration, the developing cartridge is mounted on the photosensitive cartridge by the engagement between the developing side positioning portion and the photosensitive body side positioning portion without contacting the covering member and the photosensitive body casing. Yes.

Therefore, it is possible to suppress the relative arrangement of the developing cartridge with respect to the photosensitive cartridge due to the interference between the covering member and the photosensitive casing, and the developing roller can be reliably positioned with respect to the photosensitive member.
(3) In the process cartridge of the present invention, the photosensitive cartridge includes a guide portion that guides the mounting of the developing cartridge, and the covering member includes a guided portion configured to be guided by the guide portion, In a state where the developing cartridge is mounted on the photosensitive cartridge, the guide portion and the guided portion may be separated from each other.

  According to such a configuration, the developing cartridge is mounted on the photosensitive cartridge such that the guided portion of the covering member is guided by the guiding portion of the photosensitive cartridge, and in the mounted state, the guided portion And the guide part are separated from each other.

For this reason, the developing cartridge can be reliably guided to the photosensitive cartridge by the covering member, but in a mounted state, the guided portion and the guiding portion interfere with each other, so that the developing cartridge with respect to the photosensitive cartridge is The influence on the relative arrangement can be suppressed, and the developing roller can be more reliably positioned with respect to the photosensitive member.
(4) In the process cartridge of the present invention, the covering member may include a developing electrode made of a conductive material and electrically connected to the developing roller.

  According to such a configuration, the covering member can protect the developing side positioning portion and can also be used as a developing electrode.

Therefore, the number of parts can be reduced as compared with the case where a developing electrode electrically connected to the developing roller is separately provided.
(5) In the process cartridge of the present invention, the developing cartridge further includes a supply roller configured to supply the developer to the developing roller, and the covering member is a supply electrode electrically connected to the supply roller. May be provided.

  According to such a configuration, the covering member can protect the developing-side positioning portion and can also be used as a supply electrode.

Therefore, the number of parts can be reduced as compared with the case where a supply electrode electrically connected to the supply roller is separately provided.
(6) In the process cartridge of the present invention, the developing cartridge may include an urging member, and the urging member may urge the developing housing toward the inner side in the axial direction of the rotation shaft.

  According to such a configuration, the developing cartridge can be positioned with respect to the photosensitive cartridge in the axial direction by the urging member in contact with the developing-side positioning portion.

As a result, the developing cartridge can be accurately positioned with respect to the photoreceptor cartridge.
(7) In the process cartridge of the present invention, the developing side positioning portion is a collar member that covers the end portion of the rotating shaft, and the covering member is disposed on the opposite side of the urging member with respect to the color member. The collar member may be configured to be supported by the boss by being biased by the biasing member in the covering member.

  According to such a configuration, the covering member can be assembled to the developing case in a state where the collar member is supported by the boss by the biasing member.

Therefore, the urging member, the covering member, and the collar member can be assembled all at once, so that the work efficiency can be improved.
(8) Further, in the developing cartridge of the present invention, the developing cartridge has a developing shaft and a rotating shaft, and the rotating shaft is provided at the end of the rotating shaft, and the developing roller is positioned at the end of the rotating shaft. A developing-side positioning portion and a covering member that covers the developing-side positioning portion with a space therebetween, and the covering member has an opening that exposes the developing-side positioning portion.

  According to such a configuration, the developing side positioning portion provided at the end of the rotating shaft is protected by the covering member.

  Therefore, the covering member can suppress the impact on the developing side positioning portion and the end of the rotating shaft due to the dropping of the developing cartridge or the like.

  As a result, breakage of the developing side positioning portion and the rotating shaft can be suppressed.

Further, since the developing side positioning portion is exposed from the covering member through the opening, the developing roller can be accurately positioned by positioning the developing side positioning portion with respect to the external positioning portion.
(9) Further, in the image forming apparatus of the present invention, the developing cartridge is configured to be detachable, and includes a housing, a photosensitive member supported by the housing, and a housing-side positioning unit provided in the housing, The cartridge has a developing housing, a rotating shaft, the rotating shaft is provided at the end of the rotating shaft, and the photosensitive member is engaged with the mounting portion side positioning portion. A developing-side positioning portion for positioning the developing roller with respect to the developing-side positioning portion, and a covering member that covers the developing-side positioning portion with a space therebetween, and the covering member has an opening opened downstream in the mounting direction of the developing cartridge. The housing-side positioning portion is received in the covering member through the opening and engaged with the developing-side positioning portion in a state where the developing cartridge is attached to the image forming apparatus.

  According to such a configuration, the developing roller has an accuracy with respect to the photosensitive member by engaging the developing side positioning portion provided at the end of the rotating shaft with the housing side positioning portion provided in the housing. Well positioned.

  On the other hand, the development side positioning portion is protected by a covering member having an opening for receiving the housing side positioning portion.

  Therefore, the covering member can suppress the impact on the developing side positioning portion and the end of the rotating shaft due to the dropping of the developing cartridge or the like.

  As a result, it is possible to suppress the development side positioning portion and the rotation shaft from being damaged while ensuring the positioning accuracy of the developing roller.

  In the process cartridge, the developing cartridge, and the image forming apparatus of the present invention, it is possible to suppress damage to the developing side positioning portion and the rotating shaft while ensuring the positioning accuracy of the developing roller.

FIG. 1 is a cross-sectional view showing a printer as an embodiment of an image forming apparatus of the present invention. FIG. 2 is a perspective view of the process cartridge shown in FIG. 1 viewed from the upper right side. FIG. 3 is a perspective view of the drum cartridge shown in FIG. 2 as viewed from the upper right side. FIG. 4 is a perspective view of the drum cartridge shown in FIG. 2 as viewed from the upper left side. 5A and 5B show the developing cartridge shown in FIG. 2, in which FIG. 5A is a perspective view seen from the upper right side, and FIG. 5B is a perspective view seen from the upper left side. 6 is an exploded perspective view of the developing cartridge shown in FIG. 5 as viewed from the upper right side. 7 is a cover unit shown in FIG. 6, wherein (a) is a perspective view seen from the lower left side of the right roller shaft cover, (b) is an exploded perspective view seen from the upper left side, and (c) is FIG. The temporary assembly state is shown. FIG. 8 is an explanatory view for explaining the mounting of the developing cartridge shown in FIG. 2 to the drum cartridge, wherein (a) is a right side sectional view in the middle of mounting of the developing cartridge, (b) 4A is a right side sectional view in a state where the developing cartridge is in the middle of being mounted, following (a). FIG. 9 shows a mounting state of the developing cartridge shown in FIG. 8 with respect to the drum cartridge. FIG. 9A is a right sectional view of the developing roller and the photosensitive drum in a separated state, and FIG. 9B shows the developing roller and the photosensitive drum. FIG. FIG. 10 is an explanatory view for explaining the assembly of the cover unit shown in FIG. 6, wherein (a) is a front sectional view of the cover unit in the temporarily assembled state, and (b) is attached to the developing cartridge. FIG. 6 is a front sectional view of the cover unit in a state where the cover unit is assembled to the drum cartridge. FIG. FIG. 11 is an explanatory view for explaining mounting of the developing cartridge in the printer of the second embodiment of the image forming apparatus of the present invention, and FIG. 11A is a right side sectional view in the middle of mounting of the developing cartridge. FIG. 4B is a right side sectional view in a state where the mounting of the developing cartridge is completed.

1. Overall Configuration of Printer As shown in FIG. 1, a printer 1 as an example of an image forming apparatus is a horizontal type direct tandem color printer.

  In the following description, when referring to the direction of the printer 1, the state in which the printer 1 is horizontally placed is used as the upper and lower reference. That is, the upper side in FIG. 1 is the upper side, and the lower side in FIG. 1 is the lower side. 1 is the front side, and the right side of FIG. 1 is the rear side. In addition, when the 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 right side and the back side is the left side. The up-down direction is an example of the first direction, the front-rear direction is an example of the second direction, and the axial direction (left-right direction) is an example of the third direction. The upper side is an example of one side in the first direction, and the lower side is an example of the other side in the first direction. The front side is an example of one side in the second direction, and the rear side is an example of the other side in the second direction. The right side is an example of one side in the third direction, and the left side is an example of the other side in the third direction.

  The printer 1 includes a main body casing 2 as an example of a substantially box-shaped housing. A top cover 4 that opens and closes the main body opening 3 is provided at the upper end of the main body casing 2 so as to be swingable with the rear end serving as a fulcrum. The printer 1 includes a plurality (four) of process cartridges 5.

  All the process cartridges 5 are detachably provided in the main casing 2 and are arranged in parallel at intervals. Each of the plurality (four) of process cartridges 5 corresponds to one of a plurality (four) of colors (black, yellow, magenta, cyan).

  The process cartridge 5 includes a drum cartridge 6 as an example of a photosensitive cartridge, and a developing cartridge 7 that is detachably attached to the drum cartridge 6.

  The drum cartridge 6 includes a photosensitive drum 8 as an example of a photosensitive member, and a scorotron charger 9.

  The photosensitive drum 8 includes a drum body 26, a flange member 25 (see FIG. 4), and a drum shaft 27.

  The drum body 26 is formed in a substantially cylindrical shape that is long in the left-right direction where the photosensitive layer is formed on the surface.

  The flange member 25 is formed in a substantially cylindrical shape that is fixed to both left and right ends of the drum body 26 (see FIG. 4).

  The drum shaft 27 is formed in a substantially cylindrical shape extending along the center axis of the drum body 26, and is inserted into the center of the right flange member 25 so as to be relatively rotatable (see FIG. 3).

  The photosensitive drum 8 is rotatably provided at the lower rear portion of the drum cartridge 6.

  The scorotron charger 9 is disposed opposite to the rear upper side of the photosensitive drum 8.

  The developing cartridge 7 includes a developing roller 11 as an example of a developer carrying member, and a supply roller 12 that supplies toner as an example of a developer to the developing roller 11.

  The developing roller 11 includes a metallic developing roller shaft 28 (an example of a rotating shaft) that extends in the left-right direction, and a rubber roller 29 that covers the developing roller shaft 28.

  The developing roller 11 is supported by the developing side walls 79 of the developing frame 71 at both ends in the left-right direction of the developing roller shaft 28 and is exposed from the rear side at the rear end of the developing cartridge 7 with respect to the photosensitive drum 8. Are in contact from the front upper side.

  The supply roller 12 includes a metal supply roller shaft 30 that extends in the left-right direction, and a sponge roller 31 that covers the supply roller shaft 30.

  The supply roller 12 has both end portions in the left-right direction of the supply roller shaft 30 supported by both development side walls 79 of the development frame 71 and is in contact with the development roller 11 on the front upper side of the development roller 11.

  Further, the developing cartridge 7 includes a layer thickness regulating blade 13 that regulates the thickness of the toner supplied to the rubber roller 29 of the developing roller 11. The developing cartridge 7 stores toner on the upper side of the developing roller 11 and the supply roller 12.

  The toner in the developing cartridge 7 is triboelectrically charged between the supply roller 12 and the developing roller 11 and is carried on the surface of the developing roller 11 as a thin layer having a constant thickness by the layer thickness regulating blade 13. The

  On the other hand, the surface of the drum body 26 of the photosensitive drum 8 is uniformly charged by the scorotron charger 9 and then exposed based on predetermined image data by the LED unit 10 disposed opposite to the upper side of the photosensitive drum 8. The As a result, an electrostatic latent image based on the image data is formed on the surface of the photosensitive drum 8. The toner carried on the developing roller 11 is supplied to the electrostatic latent image on the surface of the photosensitive drum 8, whereby the toner image is carried on the surface of the photosensitive drum 8.

  The paper P is accommodated in a paper feed tray 18 provided at the bottom of the main casing 2 and is conveyed by various rollers so as to make a U-turn to the upper rear side, and one sheet at a time at a predetermined timing. And the conveyor belt 19. Then, the transport belt 19 transports between all the photosensitive drums 8 and all the transfer rollers 20 from the front side to the rear side. At this time, the toner image is transferred onto the paper P.

  The paper P is heated and pressurized when passing between the heating roller 21 and the pressure roller 22. At this time, the toner image is thermally fixed on the paper P.

Thereafter, the paper P is conveyed so as to make a U-turn to the front upper side, and is discharged onto a paper discharge tray 23 provided on the top cover 4.
2. Configuration of Process Cartridge As shown in FIG. 2, the process cartridge 5 includes the drum cartridge 6 and the developing cartridge 7 as described above.

In the following description of the process cartridge 5, the drum cartridge 6, and the developing cartridge 7, when referring to the direction, the state in which the process cartridge 5 is placed horizontally is used as the front and rear reference. That is, the side where the photosensitive drum 8 is disposed is the rear side, and the opposite side is the front side. The side on which the scorotron charger 9 is provided is the upper side, and the opposite side is the lower side. The front-rear direction is an example of the fourth direction, and the up-down direction is an example of the fifth direction. The rear side is an example of one side in the fourth direction, and the front side is an example of the other side in the fourth direction. The upper side is an example of one side in the fifth direction, and the lower side is an example of the other side in the fifth direction. That is, the up-down and front-rear directions related to the process cartridge 5 are slightly different from the up-down directions related to the printer 1, and the process cartridge 5 is arranged in the printer 1 so It is installed.
(1) Drum Cartridge As shown in FIGS. 3 and 4, the drum cartridge 6 includes a drum frame 35 as an example of a photoreceptor housing.

  The drum frame 35 includes a pair of left and right drum side walls 36, a drum rear wall 37, a drum upper wall 38, a drum lower wall 39, and a drum front wall 40.

  The drum side wall 36 is formed in a substantially flat plate shape extending in the front-rear direction. The drum side wall 36 is integrally provided with a rear side portion 43 and a front side portion 44.

  The rear portion 43 is formed in a substantially rectangular shape in side view extending in the vertical direction. The rear side portion 43 is integrally provided with a bearing protection portion 47 and a collar clamping portion 49 as an example of a photoreceptor side positioning portion.

  The bearing protection portion 47 is formed in a substantially cylindrical shape that protrudes outward in the left-right direction from a substantially central portion of the rear side portion 43 on the outer side surface in the left-right direction. In the rear portion 43, a through hole (not shown) is formed in a portion surrounded by the bearing protection portion 47. A right drum bearing 57 is fitted in a through hole (not shown) in the right bearing protection part 47 and the rear part 43, and a through hole (not shown) in the left bearing protection part 47 and the rear part 43. ) Is fitted with a left drum bearing 58.

  The right drum bearing 57 is formed in a substantially cylindrical shape having a thickness in the left-right direction, and its outer diameter is smaller than the inner diameter of the bearing protection portion 47, and the inner diameter is substantially the same as the outer diameter of the drum shaft 27. Diameter (slightly larger diameter).

  The left drum bearing 58 is formed in a substantially cylindrical shape having a thickness in the left-right direction, and the outer diameter thereof is smaller than the inner diameter of the bearing protection portion 47, and the inner diameter is substantially the same as the outer diameter of the flange member 25. Same diameter (slightly larger diameter).

  The collar clamping portion 49 is formed on the front side of the bearing protection portion 47 in the rear portion 43. The collar clamping unit 49 includes a pair of clamping claws 50.

  The pair of clamping claws 50 are formed in a substantially flat plate shape that protrudes forward from the front end portion of the rear portion 43 so as to face each other in the vertical direction with a space therebetween.

  The distance between the pair of clamping claws 50 is substantially the same length (slightly longer) as the outer diameter of the inner cylinder portion 101 (described later) of the collar 100 (described later).

  The right rear portion 43 is provided with a protrusion 48.

  The protruding portion 48 is formed in a substantially prismatic shape that protrudes forward from the front end portion of the rear portion 43 above the collar clamping portion 49. The front end portion of the projecting portion 48 is disposed in front of the front end portion of the collar clamping portion 49.

  The front portion 44 continuously extends from the lower portion of the rear portion 43 to the front side of the collar clamping portion 49, and its upper surface is inclined upward from the middle portion in the front-rear direction toward the front side. It is formed in a substantially rectangular shape in a side view with a longer direction length. The rear portion of the front portion 44 includes a guide portion 53 as an example of a guide portion.

  The guide portion 53 is partitioned into an upper surface that is inclined upward toward the front in the rear portion of the front portion 44. A concave portion that is recessed in a substantially semicircular shape when viewed from the side so as to expose an input gear protection portion 143 of a drive unit 73 (described later) on an upper surface of a substantially central portion in the front-rear direction of the left front portion 44. 54 is formed.

  The drum rear wall 37 extends in the vertical and horizontal directions, and is formed in a substantially flat plate shape extending between the rear end portions of both the drum side walls 36 (between the rear end portions of the two rear portions 43).

  The drum upper wall 38 continuously extends from the upper end portion of the drum rear wall 37 to the front side, and is formed in a substantially flat plate shape extending between the upper end portions of the both drum side walls 36 (between the upper end portions of the two rear side portions 43). ing.

  The drum lower wall 39 extends in the front / rear and left / right directions, and has a substantially flat plate shape extending between the lower ends of the drum side walls 36 (between the lower ends of the front portions 44) with a distance from the lower end of the drum upper wall 38. Is formed.

  The drum front wall 40 continuously extends from the front end portion of the drum lower wall 39 to the front upper side, and is formed in a substantially flat plate shape that is laid between the front end portions of the both drum side walls 36 (between the front end portions of both front side portions 44). ing. A pressing member 66 is provided on the drum front wall 40.

  The pressing members 66 are arranged at intervals in the left-right direction, and are formed in a substantially prismatic shape having a substantially rectangular shape in a side view. The pressing member 66 is always urged rearward by an urging member (not shown).

  In the drum cartridge 6, a drum housing portion 68 that houses the photosensitive drum 8 is defined by the rear portions 43, the drum rear wall 37, the drum upper wall 38, and the drum lower wall 39. .

  In the photosensitive drum 8, the right end portion of the drum shaft 27 is inserted into the right drum bearing 57 so as to be relatively rotatable, and the left flange member 25 is held by the left drum bearing 58 so as to be relatively rotatable.

  The photosensitive drum 8 is exposed from between the drum upper wall 38 and the drum lower wall 39 (see FIGS. 1 and 8).

  The scorotron charger 9 is supported on the inner side (lower side) of the drum upper wall 38 so as to face the upper side of the photosensitive drum 8.

Further, in the drum cartridge 6, a developing cartridge mounting portion 69 that accommodates the developing cartridge 7 is partitioned by the front portions 44, the drum lower wall 39, the drum front wall 40, and the photosensitive drum 8.
(2) Developing Cartridge As shown in FIGS. 2 and 5, the developing cartridge 7 includes a developing frame 71 as an example of a developing housing, a cover unit 72 disposed on the right side of the developing frame 71, and a developing frame 71. And a drive unit 73 disposed on the left side.
(2-1) Development Frame As shown in FIG. 6, the development frame 71 is formed in a substantially box shape that extends in the left-right direction and is opened toward the rear side. Specifically, it includes a pair of development side walls 79, a development lower wall 80 (see FIG. 8A), a development front wall 81 (see FIG. 8A), and a development upper wall 82.

  Both the development side walls 79 are formed in a substantially flat plate shape having a substantially rectangular shape in side view extending in the vertical direction and are opposed to each other with an interval in the left-right direction. Further, a developing roller shaft exposure groove 83 and a supply roller shaft exposure hole 84 are formed in the development side wall 79.

  The developing roller shaft exposure groove 83 is formed in a substantially circular shape in a side view at a substantially central portion in the vertical direction of the rear end portion of the developing side wall 79. The diameter of the developing roller shaft exposure groove 83 is formed larger than the diameter of the developing roller shaft 28 of the developing roller 11. Further, the developing roller shaft exposure groove 83 is open toward the rear upper side.

  The supply roller shaft exposure hole 84 is disposed on the lower front side of the development side wall 79 on the front lower side of the development roller shaft exposure groove 83 and is formed in a substantially rectangular shape in side view. The inner dimension of the supply roller shaft exposure hole 84 is longer than the diameter of the supply roller shaft 30 of the supply roller 12. A shaft seal (not shown) is fitted in the supply roller shaft exposure hole 84.

  The shaft seal (not shown) is formed from a resin sponge or the like in a prismatic shape having a substantially rectangular shape in side view and having an outer dimension slightly larger than the supply roller shaft exposure hole 84. A supply roller shaft 30 is inserted through a central portion of a shaft seal (not shown).

  The left and right end portions of the developing roller shaft 28 are exposed from the developing roller shaft exposure groove 83 to the outside in the left and right direction of both developing side walls 79. The right end portion of the developing roller shaft 28 exposed from the developing roller shaft exposure groove 83 includes a large diameter portion 91, a small diameter portion 92, and a medium diameter portion 93.

  The large diameter portion 91 is formed in a substantially cylindrical shape extending rightward from the right end surface of the rubber roller 29 of the developing roller 11. The large-diameter portion 91 has a length in the left-right direction that is longer than a length in the left-right direction of the developing roller shaft exposure groove 83, and a diameter that is smaller than the inner diameter of the developing roller shaft exposure groove 83.

  The small-diameter portion 92 extends to the right continuously from the right end portion of the large-diameter portion 91 and is formed in a substantially cylindrical shape that shares the central axis with the large-diameter portion 91. The diameter of the small diameter portion 92 is smaller than the diameter of the large diameter portion 91.

  The middle diameter portion 93 extends to the right continuously from the right end portion of the small diameter portion 92 and is formed in a substantially cylindrical shape sharing a central axis with the large diameter portion 91 and the small diameter portion 92. The diameter of the medium diameter portion 93 is smaller than that of the large diameter portion 91 and larger than that of the small diameter portion 92. The peripheral surface at the right end of the medium diameter portion 93 is chamfered.

  Further, both end portions in the left-right direction of the supply roller shaft 30 are exposed to the outside in the left-right direction of the development side walls 79 from the supply roller shaft exposure holes 84.

  The left end portion of the developing roller shaft 28 and the left end portion of the supply roller shaft 30 are connected to a gear train 160 (described later) so as to be able to transmit driving.

  A pair of engaging convex portions 85 are provided on the right developing side wall 79.

  Each of the pair of engaging convex portions 85 is disposed on the upper side and the lower side of the developing roller shaft exposure groove 83. The engaging convex portion 85 is formed in a substantially cylindrical shape protruding rightward from the right surface of the developing side wall 79.

  The developing lower wall 80 (see FIG. 8A) is formed in a substantially flat plate shape extending in the left-right direction, and is integrally built between the lower end portions of both developing side walls 79.

  The development front wall 81 (see FIG. 8A) is formed in a substantially flat plate shape extending in the left-right direction, extends continuously upward from the front end portion of the development lower wall 80, and between the front end portions of the development side walls 79. It is erected integrally.

The development upper wall 82 is formed in a substantially flat plate shape extending in the left-right direction, and is opposed to the upper end portions of the front wall 81 and the development side walls 79 from above. The development upper wall 82 is fixed to the front edge of the development wall 81 and the upper ends of both development side walls 79 by a method such as welding at the peripheral edge.
(2-2) Cover Unit As shown in FIG. 5A, the cover unit 72 includes a right roller shaft cover 114 as an example of a covering member, a color 100 as an example of a developing side positioning portion and a color member, And a spring 110 as an example of an urging member.

  The right roller shaft cover 114 is made of a conductive resin material, and is disposed on the right side of the rear end portion of the right developing side wall 79. The right roller shaft cover 114 is integrally provided with a base plate 115 and a collar protector 116.

  As shown in FIG. 7, the base plate 115 is formed in a substantially flat plate shape that is substantially rectangular in a side view. The base plate 115 is formed with a developing roller shaft insertion hole 118, a plurality (two) of engagement recesses 119, a supply roller shaft insertion hole 120, and a through hole 121. Further, the base plate 115 includes a locking claw 122, a developing roller shaft insertion portion 123, a square tube portion 124, and a supply roller shaft insertion portion 125 (see FIG. 6).

  The developing roller shaft insertion hole 118 is formed in a substantially circular shape in a side view at a substantially central portion in the vertical direction in the rear portion of the base plate 115. The inner diameter of the developing roller shaft insertion hole 118 is larger than the large diameter portion 91 of the developing roller shaft 28 and smaller than the inner diameter of the developing roller shaft exposure groove 83.

  The plurality of engaging recesses 119 are arranged one by one above and below the developing roller shaft insertion hole 118. The engaging recess 119 is formed so as to be recessed in a substantially square shape in a side view from the left surface to the right side of the base plate 115. The inner dimension of the engagement recess 119 is substantially the same (slightly larger) as the outer diameter of the engagement protrusion 85.

  The supply roller shaft insertion hole 120 is formed in a substantially circular shape in a side view on the front lower side of the developing roller shaft insertion hole 118. The inner diameter of the supply roller shaft insertion hole 96 is substantially the same diameter (slightly larger) as the diameter of the supply roller shaft 30.

  The through hole 121 is formed in a substantially circular shape when viewed from the side above the supply roller shaft insertion hole 120.

  The locking claw 122 is formed in a substantially bowl shape that protrudes leftward from the front side of the lower engaging recess 119.

  The developing roller shaft insertion portion 123 is formed in a substantially cylindrical shape that shares the central axis with the developing roller shaft insertion hole 118 so as to protrude to the left from the peripheral portion of the development roller shaft insertion hole 118.

  The rectangular tube portion 124 is formed in a substantially rectangular tube shape having a through hole sharing the central axis with the supply roller shaft insertion hole 120 so as to protrude to the left from the peripheral portion of the supply roller shaft insertion hole 120.

  As shown in FIG. 6, the supply roller shaft insertion portion 125 is formed in a substantially cylindrical shape that shares the central axis with the supply roller shaft insertion hole 120 so as to protrude rightward from the peripheral portion of the supply roller shaft insertion hole 120. ing.

  As shown in FIG. 7, the color protection unit 116 is formed on the right side in the rear portion of the base plate 115. The color protection part 116 includes a semi-cylindrical part 126, a closing part 127, and a contacted part 128.

  The semi-cylindrical portion 126 is formed so as to protrude rightward from the right surface of the base plate 115 in a substantially U shape in a side view with the rear side opened. The inner diameter of the semi-cylindrical portion 126 is larger than the outer diameter of the outer cylinder portion 102 of the collar 100. Further, the outer peripheral surface of the semi-cylindrical portion 126 is partitioned as a guided portion 130, and the open portion of the semi-cylindrical portion 126 is partitioned as an opening 131.

  The closing portion 127 is formed in a substantially semicircular shape that closes the right end portion of the semicylindrical portion 126. A boss 132 is formed in the closing portion 127.

  The boss 132 is formed in a substantially cylindrical shape that shares the central axis with the developing roller shaft insertion hole 118 so as to protrude from the substantially central portion of the left surface of the closing portion 127 to the left side.

  The contacted portion 128 is formed in a substantially prismatic shape protruding rightward from the right surface at the rear lower end portion of the closing portion 127.

  Further, in the right roller shaft cover 114, the collar accommodating portion 135 is partitioned by the front portion of the base plate 115, the semi-cylindrical portion 126, and the closing portion 127.

  The collar 100 includes an inner cylinder portion 101 and an outer cylinder portion 102.

  The inner cylinder part 101 is formed in a substantially cylindrical shape extending in the left-right direction. The inner cylinder portion 101 has an inner diameter that is substantially the same diameter (slightly larger) as that of the middle diameter portion 93. The inner cylinder portion 101 includes a cut 104 and a locking portion 103.

  Two notches 104 are formed so as to be cut out from the inner end of the inner cylinder portion 101 in the left-right direction toward the outer side in the left-right direction. The length in the left-right direction of the cut 104 is shorter than the length in the left-right direction of the outer cylinder portion 102 (described later).

  The locking portion 103 is formed as a protrusion that protrudes radially inward from the inner peripheral surface of the inner cylindrical portion 101 in the left-right direction inner end, and extends in the radial direction of the inner cylindrical portion 101. The radially inner side surface of the locking portion 103 is formed so as to incline radially inward from the inner side in the left-right direction toward the outer side in the left-right direction. The inner diameter of the locking portion 103 is smaller than the diameter of the medium diameter portion 93 and larger than the diameter of the small diameter portion 92.

  The outer cylinder part 102 is disposed at a distance from the circumferential surface of the inner cylinder part 101 in the left-right direction inner side to the outer side in the radial direction, and is formed in a substantially cylindrical shape sharing the central axis with the inner cylinder part 101. The outer peripheral edge of the outer cylinder part 102 on the outer side in the left-right direction and the peripheral surface of the central part in the left-right direction of the inner cylinder part 101 are connected by a connecting part 105.

  The connecting portion 105 is formed in a substantially annular shape, and its radially outer surface is formed so as to incline radially inward from the inner side in the left-right direction toward the outer side in the left-right direction.

The spring 110 is formed in a spiral shape extending in the left-right direction. The inner diameter of the spring 110 is larger than the diameter of the inner cylinder portion 101 and the diameter of the developing roller shaft insertion hole 118, and the outer diameter thereof is smaller than the inner diameter of the outer cylinder portion 102.
(2-3) Assembly of Cover Unit to Development Frame Next, assembly of the cover unit 72 to the development frame 71 will be described.

  In order to assemble the cover unit 72 to the developing frame 71, first, the cover unit 72 is temporarily assembled.

  To temporarily assemble the cover unit 72, the spring 110 is assembled to the collar 100 from the left side as shown in FIG. Specifically, the spring 110 is fitted between the inner cylinder portion 101 and the outer cylinder portion 102 of the collar 100. Thereby, the right end portion of the spring 110 is brought into contact with the right surface of the connecting portion 105.

  Next, the collar 100 in which the spring 110 is fitted is assembled to the right roller shaft cover 114 from the rear side. Specifically, as shown in FIGS. 7C and 10A, the collar 100 and the spring 110 are pressed through the opening 131 while pressing the spring 110 to the right against the collar 100. When projected in the left-right direction, the boss 132 of the right roller shaft cover 114 is moved forward so that the boss 132 is disposed inside the inner diameter of the inner cylinder portion 101 of the collar 100, and the color accommodating portion of the right roller shaft cover 114 is moved. 135.

  Next, when the pressure of the spring 110 against the collar 100 is released, the left end portion of the spring 110 and the right surface of the base plate 115 are brought into contact with each other, and the collar 100 is urged to the right side by the urging force of the spring 110.

  Thereby, the boss 132 is disposed in the inner cylinder portion 101, and the collar 100 is supported by the boss 132.

  As described above, the collar 100 and the spring 110 are held in the collar accommodating portion 135 of the right roller shaft cover 114, and the temporary assembly of the cover unit 72 is completed.

  Next, as shown in FIG. 6, the temporarily assembled cover unit 72 is pushed in from the right side of the developing frame 71.

  Then, the square tube portion 124 is fitted into the supply roller shaft exposure hole 84, whereby the right end portion of the supply roller shaft 30 is inserted into the supply roller shaft insertion hole 120.

  Further, the right end portion of the developing roller shaft 28 is inserted so as to come into contact with the developing roller shaft insertion hole 118.

  Further, when the cover unit 72 is pushed to the left side with respect to the developing frame 71, each of the plurality of engaging convex portions 85 is fitted into the plurality of engaging concave portions 119, and the right roller shaft cover 114 is connected to the developing frame. Positioned with respect to 71.

  As a result, as shown in FIGS. 5A and 10B, the developing roller shaft insertion portion 123 has the large-diameter portion 91 of the developing roller shaft 28 inserted therethrough and the developing roller shaft exposure groove. 83.

  Further, the middle diameter portion 93 of the developing roller shaft 28 passes through the spring 110 and is inserted into the inner cylinder portion 101 of the collar 100, and the right surface of the locking portion 103 is brought into contact with the left end surface thereof. Stopped.

  Then, the screw 88 is screwed into the screw hole (not shown) of the developing side wall 79 on the right side of the developing frame 71 through the through hole 121, whereby the assembly of the cover unit 72 to the developing frame 71 is completed.

At this time, the rear portion of the collar 100 is exposed from the opening 131 of the right roller shaft cover 114.
(2-4) Drive Unit The drive unit 73 includes a gear train 160 and a gear cover 139 as shown in FIGS. 5B and 6. Note that the collar 100 and the spring 110 are assembled to the left end portion of the developing roller shaft 28 of the developing roller 11, similarly to the cover unit 72.

  The gear train 160 includes an input gear 161, a developing roller gear 162, an idle gear 163, an idle gear 163, and a detection gear 164.

  The input gear 161 is disposed at a substantially central portion of the left developing side wall 79 in the vertical direction.

  The developing roller gear 162 is disposed at the left end portion of the developing roller 11 so as not to be relatively rotatable.

  The idle gear 163 is meshed with the input gear 161 from the front side.

  The detection gear 164 is meshed with the idle gear 163 from the front upper side.

  Then, a driving force from the outside is input to the input gear 161, and the driving force is transmitted to the developing roller gear 162, the idle gear 163 and the detection gear 164.

  The gear cover 139 is formed from an insulative resin material in a substantially flat plate shape that is substantially rectangular in a side view in the longitudinal direction. The gear cover 139 integrally includes a gear protection unit 140 and a left roller shaft cover 150 as an example of a covering member.

  The gear protector 140 has a substantially flat plate shape that is substantially rectangular in a side view in the front-rear direction so as to cover the input gear 161, the idle gear 163, and the detection gear 164 at the front portion of the gear cover 139. Is formed. Further, the gear protection part 140 is formed with a plurality (two) of through holes 141 and an input gear insertion hole 142. Further, the gear protection unit 140 includes an input gear protection unit 143.

  The plurality of through holes 141 are arranged one by one at the front upper end and the rear upper end of the gear protection unit 140. The through hole 141 is formed in a substantially circular shape when viewed from the side.

  The input gear insertion hole 142 is formed in a substantially circular shape when viewed from the side at a substantially central portion of the gear protection portion 140 in the vertical direction. The inner diameter of the input gear insertion hole 142 is slightly larger than that of the input gear 161.

  The input gear protection part 143 is formed in a substantially cylindrical shape that shares the central axis with the input gear insertion hole 142 so as to protrude rightward from the peripheral edge of the input gear insertion hole 142.

  The left roller shaft cover 150 is formed so as to continue from the front end of the gear protector 140 and protrude leftward. The left roller shaft cover 150 includes a semi-cylindrical portion 152, a closing portion 153, and a contacted portion 154.

  The semi-cylindrical portion 152 is formed so as to protrude to the left from the rear end edge of the gear protection portion 140 in a substantially U shape in a side view when the rear side is opened. The inner diameter of the semi-cylindrical part 152 is larger than the outer diameter of the outer cylinder part 102 of the collar 100. Further, the outer peripheral surface of the semi-cylindrical portion 152 is partitioned as a guided portion 156, and the open portion of the semi-cylindrical portion 152 is partitioned as an opening 157.

  The closing portion 153 is formed in a substantially semicircular shape that closes the left end portion of the semicylindrical portion 152.

  The contacted portion 154 is formed in a substantially prismatic shape protruding leftward from the left surface at the rear lower end portion of the closing portion 153.

  Further, in the left roller shaft cover 150, the collar housing portion 166 is partitioned by the semi-cylindrical portion 152 and the closing portion 153.

  As shown in FIG. 5, the gear cover 139 covers the input gear 161 with the input gear protection unit 143, and the screw 88 is provided on the left side of the developing side wall 79 of the developing frame 71 through the plurality of through holes 141. It is held by being screwed into a screw hole (not shown).

  Thereby, the gear protection unit 140 collectively protects the input gear 161, the idle gear 163, and the detection gear 164.

  Further, the left roller shaft cover 150 accommodates the collar 100 assembled at the left end portion of the developing roller 11 in the color accommodating portion 166.

The rear portion of the collar 100 is exposed from the opening 157 of the left roller shaft cover 150.
(3) Mounting of developing cartridge to drum cartridge To mount the developing cartridge 7 to the drum cartridge 6, as shown in FIG. 8A, the rear end of the developing cartridge 7 is connected to the developing cartridge mounting portion of the drum cartridge 6. Insert into 69 from above.

  Then, the guided portion 130 of the right roller shaft cover 114 and the guided portion 156 of the left roller shaft cover 150 abut against the guide portion 53 of the drum side wall 36.

  Next, the developing cartridge 7 is rotated substantially counterclockwise as viewed from the right side with the contact portion between each guided portion (guided portion 130 and guided portion 156) and the guide portion 53 as a fulcrum. It is moved rearward and downward along the part 53.

  Then, as shown in FIG. 8B, on the right side, the clamping claws 50 of the collar clamping part 49 are received in the collar accommodating part 135 through the opening 131.

  Further, when the developing cartridge 7 is moved rearward and downward along the guide portion 53 while being rotated approximately counterclockwise as viewed from the right side with respect to the drum cartridge 6, as shown in FIG. The clamping claw 50 of the collar clamping unit 49 clamps the collar 100 in the color storage unit 135. Specifically, the clamping claw 50 first contacts the connecting portion 105 of the collar 100 from the rear side. Since the interval between the holding claws 50 is substantially the same as the outer diameter of the inner cylinder portion 101, the collar 100 is brought into contact with the holding claws 50 as shown in FIG. The inner cylinder 101 and the boss 132 are separated from each other against the biasing force of the spring 110, and the inner cylinder 101 is clamped by the clamping claws 50. That is, the right roller shaft cover 114 covers the collar 100 so as to be spaced from the collar 100.

  The guided portion 130 and the guide portion 53 are separated from each other by the inner cylinder portion 101 being clamped by the clamping claws 50.

  Although not shown in the drawing, on the left side, similarly to the right side, the clamping claws 50 of the collar clamping unit 49 are received in the collar housing unit 166 through the opening 157 and clamp the collar 100. On the left side, the clamping claw 50 does not contact the connecting portion 105 and clamps the inner cylinder portion 101.

  The guided portion 156 and the guide portion 53 are separated from each other by the inner cylinder portion 101 being held by the holding claws 50.

As a result, as shown in FIG. 9B, the developing cartridge 7 is supported on the drum cartridge 6 by the collar clamping portion 49 at both ends in the left-right direction and is pressed to the left by the biasing force of the spring 110. Then, it is mounted on the developing cartridge mounting portion 69. That is, the photosensitive drum 8 is positioned with respect to the developing roller 11 by the engagement between the color clamping portion 49 and the collar 100. At this time, the right roller shaft cover 114 and the drum frame 35 are separated from each other.
3. Structure of Main Body Casing As shown in FIG. 2, the main body casing 2 includes a main body electrode 170 and a pressing / separating member 173.

  A plurality (four) of body electrodes 170 are provided corresponding to each of the process cartridges 5 so as to be electrically connected to the process cartridge 5. The main body electrode 170 is in contact with the right roller shaft cover 114 of the cover unit 72 of the process cartridge 5 from the right side when the process cartridge 5 is mounted on the main body casing 2.

  As a result, electric power from the outside is supplied to the developing roller 11 via the developing roller shaft insertion portion 123 of the cover unit 72 and supplied via the rectangular tube portion 124 and the supply roller shaft insertion portion 125 of the cover unit 72. Supplied to the roller 12. That is, the developing roller shaft insertion portion 123 is configured as an example of a developing electrode, and the square tube portion 124 is configured as an example of a supply electrode.

  A plurality of pairs (four pairs) of pressing / separating members 173 are provided corresponding to each of the process cartridges 5. The plural pairs of pressing / separating members 173 are arranged at equal intervals in the front-rear direction on both outer sides in the left-right direction of the process cartridge 5. The pressing / separating member 173 includes a pressing / separating shaft 174, a force receiving portion 175, and a contact portion 176.

  The pressing / separating shaft 174 is formed in a substantially cylindrical shape that is long in the left-right direction, and is supported so as to be rotatable relative to the main body casing 2.

  The force receiving portion 175 is formed in a substantially flat plate shape extending downward from the peripheral surface on the lower side of the pressing / separating shaft 174.

  The contact portion 176 is formed in a substantially flat plate shape extending upward from the peripheral surface on the upper side of the pressing / separating shaft 174.

  The pressing / separating member 173 is rotated substantially counterclockwise as viewed from the right side about the pressing / separating shaft 174 when an external driving force is input to the force receiving portion 175.

  In this way, the contact portion 176 is brought into contact with the contacted portion 128 of the color protection portion 116 and the contacted portion 154 of the left roller shaft cover 150, whereby the developing cartridge 7 is pressed against the pressing member of the drum cartridge 6. It is moved to the front upper side against the urging force of 66.

  As a result, the developing roller 11 of the developing cartridge 7 and the photosensitive drum 8 of the drum cartridge 6 are separated from each other (see FIG. 9A).

  In addition, when the pressing / separating member 173 is rotated about the pressing / separating shaft 174 in the clockwise direction when viewed from the right side, the contact portion 176 includes the contacted portion 128 of the color protection portion 116 and the left roller. The shaft cover 150 is separated from the contacted portion 154.

As a result, the developing cartridge 7 is pressed by the urging force of the pressing member 66, and the developing roller 11 and the photosensitive drum 8 are brought into contact with each other.
4). Action Effect (1) According to this process cartridge 5, as shown in FIGS. 8 and 9, the developing roller 11 is provided with the collar 100 provided at the end of the developing roller shaft 28. By being pinched by the pinching claws 50 of the pinching portion 49, it is accurately positioned with respect to the photosensitive drum 8.

  On the other hand, the collar 100 is protected by a right roller shaft cover 114 having an opening 131 for receiving the collar clamping portion 49 and a left roller shaft cover 150 having an opening 157 as shown in FIG.

  Therefore, the right roller shaft cover 114 and the left roller shaft cover 150 can suppress impacts on the end portions of the collar 100 and the developing roller shaft 28 due to the dropping of the developing cartridge 7 or the like.

As a result, damage to the collar 100 and the developing roller shaft 28 can be suppressed while ensuring the positioning accuracy between the photosensitive drum 8 and the developing roller 11.
(2) Further, according to this process cartridge 5, as shown in FIGS. 8 and 9, the collar 100 is not colored without contacting the right roller shaft cover 114, the left roller shaft cover 150, and the drum frame 35. The developing cartridge 7 is attached to the drum cartridge 6 by being clamped by the clamping claws 50 of the clamping unit 49.

Therefore, the interference between the right roller shaft cover 114 and the left roller shaft cover 150 and the drum frame 35 can prevent the relative arrangement of the developing cartridge 7 with respect to the drum cartridge 6 from being affected. 8 can be reliably positioned.
(3) Also, according to this process cartridge 5, as shown in FIGS. 8 and 9, the developing cartridge 7 is guided to the drum cartridge 6 by each guided portion (the guided portion 130 of the right roller shaft cover 114, The guided portion 156 of the left roller shaft cover 150 is mounted so as to be guided by the guide portion 53 of the drum cartridge 6, and in the mounted state, each guided portion (guided of the right roller shaft cover 114). Portion 130 and guided portion 156 of left roller shaft cover 150 and guide portion 53 are separated from each other.

For this reason, the developing cartridge 7 can be reliably guided to the drum cartridge 6 by the right roller shaft cover 114 and the left roller shaft cover 150, but in the mounted state, each guided portion (right roller shaft cover 114). The guided portion 130 and the guided portion 156 of the left roller shaft cover 150) and the guide portion 53 can be prevented from affecting the relative arrangement of the developing cartridge 7 with respect to the drum cartridge 6, The developing roller 11 can be more reliably positioned with respect to the photosensitive drum 8.
(4) Also, according to the process cartridge 5, as shown in FIG. 5, the right roller shaft cover 114 is made of a conductive resin material, and the developing roller shaft of the developing roller 11 is inserted into the developing roller shaft insertion portion 123. The right end part of 28 is inserted so that it may contact.

  Therefore, the right roller shaft cover 114 can protect the collar 100 and can also be used as a developing electrode.

As a result, the number of parts can be reduced as compared with the case where a developing electrode electrically connected to the developing roller 11 is separately provided.
(5) Also, according to the process cartridge 5, as shown in FIG. 5, the right roller shaft cover 114 is made of a conductive resin material, and the supply roller is inserted into the rectangular tube portion 124 and the supply roller shaft insertion portion 125. The 12 supply roller shafts 30 are inserted so that the right end portions thereof are in contact with each other.

  Therefore, the right roller shaft cover 114 can protect the collar 100 and can also be used as a supply electrode.

Therefore, the number of parts can be reduced as compared with the case where a supply electrode electrically connected to the supply roller is separately provided.
(6) Also, according to this process cartridge 5, as shown in FIGS. 2 and 5, the developing cartridge 7 is positioned with respect to the drum cartridge 6 in the left-right direction (axial direction) by the spring 110 that is in contact with the collar 100. be able to.

As a result, the developing cartridge 7 can be accurately positioned with respect to the drum cartridge 6.
(7) According to this process cartridge 5, as shown in FIGS. 6 and 7, the right roller shaft cover 114 is assembled to the developing frame 71 in a state where the collar 100 is supported by the boss 132 by the spring 110. Can do.

Therefore, since the spring 110, the right roller shaft cover 114, and the collar 100 can be assembled all at once, the working efficiency can be improved.
(8) Also, according to the developing cartridge 7, as shown in FIG. 5, the collar 100 provided at the end of the developing roller shaft 28 is protected by the right roller shaft cover 114 and the left roller shaft cover 150. .

  Therefore, the right roller shaft cover 114 and the left roller shaft cover 150 can suppress impacts on the end portions of the collar 100 and the developing roller shaft 28 due to the dropping of the developing cartridge 7 or the like.

  As a result, damage to the collar 100 and the developing roller shaft 28 can be suppressed.

Further, since the collar 100 is exposed through the opening 131 of the right roller shaft cover 114 and the opening 157 of the left roller shaft cover 150, the collar 100 is developed by positioning it with respect to the external positioning portion. The roller 11 can be accurately positioned.
5. Second Embodiment With reference to FIG. 11, a second embodiment of the image forming apparatus of the present invention will be described. In the second embodiment, members similar to those in the first embodiment described above are denoted by the same reference numerals, and description thereof is omitted.

  In the first embodiment described above, the drum cartridge 6 of the process cartridge 5 includes the photosensitive drum 8 and the color clamping portion 49. When the developing cartridge 7 is assembled to the drum cartridge 6, the collar 100 provided on the developing roller shaft 28 of the developing roller 11 and the color clamping portion 49 are engaged, and the developing roller 11 is positioned with respect to the photosensitive drum 8. (See FIG. 8 and FIG. 9).

  On the other hand, in the second embodiment of the present invention, the main body casing 2 includes a photosensitive drum 180 as an example of a photoconductor and a color clamping unit 181 as an example of a housing side positioning unit.

  The photosensitive drum 180 is rotatably provided on a main body frame (referred to as a main body frame 179) disposed inside the left and right side walls of the main body casing 2.

  The color clamping unit 181 is formed in a front side portion of the main body frame 179 with respect to the photosensitive drum 180. The collar clamping unit 181 includes a pair of clamping claws 182.

  The pair of clamping claws 182 are formed in a substantially flat plate shape that protrudes forward so as to face each other in the vertical direction with a gap therebetween.

  The distance between the pair of guide portions 183 is substantially the same length (slightly longer) as the outer diameter of the inner cylinder portion 101 of the collar 100.

  The main body frame 179 continuously extends from the lower side of the photosensitive drum 180 to the front side, and is formed such that its upper surface is inclined upward from the middle part in the front-rear direction toward the front side. An upper surface of the main body frame 179 that is inclined upward toward the front is defined as a guide portion 183.

  In order to attach the developing cartridge 7 to the main casing 2, the rear end portion of the developing cartridge 7 is inserted into the main casing 2 from the upper side.

  Then, the guided portion 130 of the right roller shaft cover 114 and the guided portion 156 of the left roller shaft cover 150 come into contact with the guide portion 183 of the main body frame 179.

  Next, with the guided portion (guided portion 130 and guided portion 156) and the contact portion between the guide portion 183 as a fulcrum, the developing cartridge 7 is rotated substantially counterclockwise as viewed from the right side while guiding the guide. It is moved rearward and downward along the part 183.

  Then, on the right side, the clamping claws 182 of the collar clamping unit 181 are received in the collar accommodating unit 135 through the opening 131.

  Further, when the developing cartridge 7 is moved rearward and downward along the guide portion 183 while rotating substantially counterclockwise as viewed from the right side with respect to the drum cartridge 6, the holding claws 182 of the collar holding portion 181 are The collar 100 in the color container 135 is sandwiched. Specifically, the clamping claw 182 first comes into contact with the connecting portion 105 of the collar 100 from the rear side. Since the interval between the holding claws 182 is substantially the same as the outer diameter of the inner cylinder portion 101, the collar 100 resists the biasing force of the spring 110 when the connecting portion 105 is brought into contact with the holding claws 182. The inner cylinder part 101 and the boss 132 are separated from each other, and the inner cylinder part 101 is clamped by the clamping claws 182. That is, the right roller shaft cover 114 covers the collar 100 so as to be spaced from the collar 100.

  When the inner cylinder portion 101 is clamped by the clamping claws 182, the guided portion 130 and the guide portion 183 are separated from each other.

  Although not shown in the drawing, on the left side, similarly to the right side, the clamping claws 182 of the collar clamping unit 181 are received in the collar housing unit 166 through the opening 157 and clamp the collar 100. On the left side, the sandwiching claws 182 are not in contact with the connecting portion 105 and sandwich the inner cylinder portion 101.

  When the inner cylinder portion 101 is clamped by the clamping claws 182, the guided portion 156 and the guide portion 183 are separated from each other.

  As a result, both the left and right end portions of the developing cartridge 7 are supported by the drum cartridge 6 by the collar clamping portion 49 and are mounted in the main casing 2 while being pressed to the left by the urging force of the spring 110. That is, the photosensitive drum 180 is positioned with respect to the developing roller 11 by the engagement between the color clamping unit 181 and the color 100.

  According to the second embodiment, as shown in FIG. 11, the developing roller 11 has the collar 100 provided at the end of the developing roller shaft 28 connected to the clamping claws 182 of the collar clamping portion 181 provided in the main body casing 2. By being pinched, it is accurately positioned with respect to the photosensitive drum 180.

  On the other hand, the collar 100 is protected by a right roller shaft cover 114 having an opening 131 for receiving the collar clamping portion 181 and a left roller shaft cover 150 having an opening 157.

  Therefore, the right roller shaft cover 114 and the left roller shaft cover 150 can suppress impacts on the end portions of the collar 100 and the developing roller shaft 28 due to the dropping of the developing cartridge 7 or the like.

  As a result, damage to the collar 100 and the developing roller shaft 28 can be suppressed while ensuring the positioning accuracy of the developing roller 11.

Also in the second embodiment, the same effects as those in the first embodiment described above can be obtained.
6). Other Embodiments The process cartridge 5 described above is an embodiment of the present invention, and the present invention is not limited to the above-described embodiment.

  The process cartridge 5 according to an embodiment of the present invention is mounted on a printer 1 as an example of an image forming apparatus. The image forming apparatus includes a plurality of photoconductors and an intermediate transfer in addition to the direct tandem type color printer described above. An intermediate transfer type tandem color printer including a body and a transfer member can be configured. In addition to a color printer, the printer can also be configured as a monochrome printer.

  Further, instead of the above-described photosensitive drum 8, for example, a photosensitive member such as a photosensitive belt can be applied.

  Further, instead of the developing roller 11 described above, for example, a developer carrier such as a developing sleeve, a developing belt, or a brush-like roller can be applied.

  Further, instead of the supply roller 12 described above, for example, a supply member such as a supply sleeve, a supply belt, or a brush-like roller can be applied.

  Further, instead of the transfer roller 20 described above, for example, a contact type transfer member such as a transfer belt, a transfer brush, a transfer blade, or a film type transfer device, or a non-contact type transfer member such as a corotron type is used. It can also be applied.

  Further, in place of the scorotron charger 9 described above, for example, a non-contact charger such as a corotron charger, a sawtooth discharge member, or a contact charger such as a charging roller may be applied. it can.

  Further, instead of the LED unit 10 described above, an exposure member such as a scanner unit can be applied.

  Furthermore, the image forming apparatus of the present invention can also be configured as a multi-function peripheral equipped with an image reading unit and the like.

  Further, the above-described collar 100 is configured as an example of the developing side positioning unit, but does not include the collar 100, and the developing roller shaft 28 is configured as an example of the developer positioning unit and is sandwiched between the clamping claws 50. You can also.

DESCRIPTION OF SYMBOLS 1 Printer 2 Main body casing 5 Process cartridge 6 Drum cartridge 7 Developing cartridge 8 Photosensitive drum 11 Developing roller 12 Supply roller 28 Developing roller shaft 35 Drum frame 49 Color clamping part 53 Guide part 71 Developing frame 100 Color 110 Spring 114 Right roller shaft cover 130 Guided part 131 Opening 132 Boss 150 Left roller shaft cover 156 Guided part 157 Opening 180 Photosensitive drum 181 Color clamping part 183 Guide part

Claims (9)

A photoreceptor cartridge;
A developing cartridge configured to be attached to the photosensitive cartridge,
The photosensitive cartridge is
A photoconductor housing;
A photoreceptor supported by the photoreceptor casing;
A photoconductor side positioning portion provided in the photoconductor case,
The developing cartridge is
A developing case;
A developing roller having a rotating shaft, the rotating shaft being supported by the developing housing;
A developing-side positioning portion that is provided at an end of the rotating shaft and positions the developing roller with respect to the photoconductor by engagement with the photoconductor-side positioning portion;
A coating member that covers the development-side positioning portion with a space therebetween;
The covering member is
An opening that is opened downstream in the mounting direction of the developing cartridge;
The photoreceptor-side positioning portion is received in the covering member through the opening and engaged with the development-side positioning portion in a state where the developing cartridge is mounted on the photoreceptor cartridge. A feature of the process cartridge.   2. The process cartridge according to claim 1, wherein the covering member is not in contact with the photosensitive member housing in a state where the developing cartridge is mounted on the photosensitive member cartridge. The photosensitive cartridge includes a guide unit for guiding the mounting of the developing cartridge,
The covering member includes a guided portion configured to be guided by the guide portion,
3. The process cartridge according to claim 1, wherein the guide portion and the guided portion are separated from each other in a state where the developing cartridge is attached to the photosensitive cartridge.   4. The process cartridge according to claim 1, wherein the covering member includes a developing electrode made of a conductive material and electrically connected to the developing roller. 5. The developer cartridge further comprises a supply roller configured to supply developer to the developer roller;
The process cartridge according to claim 4, wherein the covering member includes a supply electrode electrically connected to the supply roller. The developing cartridge has a biasing member,
6. The process cartridge according to claim 1, wherein the urging member urges the developing housing toward the inner side in the axial direction of the rotation shaft. The development-side positioning portion is a color member that covers an end portion of the rotating shaft,
The covering member includes a boss disposed on the opposite side of the biasing member with respect to the collar member,
The process cartridge according to claim 6, wherein the collar member is configured to be supported by the boss by being urged by the urging member in the covering member. A developing case;
A developing roller having a rotating shaft, the rotating shaft being supported by the developing housing;
A developing side positioning portion for positioning the developing roller provided at an end of the rotating shaft;
A coating member that covers the development-side positioning portion with a space therebetween;
The developing cartridge according to claim 1, wherein the covering member includes an opening exposing the developing side positioning portion. An image forming apparatus configured to be detachable from a developing cartridge,
The image forming apparatus includes:
A housing,
A photoreceptor supported by the housing;
A housing side positioning portion provided in the housing,
The developing cartridge is
A developing case;
A developing roller having a rotating shaft, the rotating shaft being supported by the developing housing;
A developing-side positioning portion that is provided at an end of the rotating shaft and positions the developing roller with respect to the photoconductor by engagement with the housing-side positioning portion;
A coating member that covers the development-side positioning portion with a space therebetween;
The covering member is
An opening that is opened downstream in the mounting direction of the developing cartridge;
The casing-side positioning portion is received in the covering member through the opening and engaged with the developing-side positioning portion in a state where the developing cartridge is mounted on the image forming apparatus. An image forming apparatus as a feature.

Images