阅读说明：本技术 处理盒、以及具备处理盒的图像形成装置 (Process cartridge and image forming apparatus including process cartridge ) 是由 山口淳 于 2019-06-24 设计创作，主要内容包括：本发明提供能够通过简单的操作使感光体单元和显影单元一体化以及分离的处理盒。处理盒(10)通过感光体单元(34)与显影单元(36)以能够分离的方式一体化而构成。感光体单元以及显影单元具备：使各单元彼此定位并一体化的嵌合部(50a、56a、116、134)、将各单元向一体化位置引导的组装引导件(118、136)、以及在一体化位置保持各单元的防脱部(120、142)。(The invention provides a process cartridge which can integrate and separate a photosensitive body unit and a developing unit through simple operation. The process cartridge (10) is configured by integrating a photosensitive body unit (34) and a developing unit (36) in a separable manner. The photoreceptor unit and the developing unit are provided with: fitting sections (50a, 56a, 116, 134) for positioning and integrating the units, assembly guides (118, 136) for guiding the units to an integration position, and retaining sections (120, 142) for holding the units at the integration position.)

1. A process cartridge in which a photosensitive body unit including a photosensitive drum and a developing unit including a developing roller are separably integrated and are detachably attached to and detached from an apparatus main body of an image forming apparatus in an integrated state,

the photoreceptor unit and the developing unit are provided with:

a fitting portion that positions and integrates the photosensitive body unit and the developing unit by fitting in an axial direction of the photosensitive drum;

an assembly guide engaged with the photosensitive body unit so as to be slidable in the axial direction, the assembly guide guiding the photosensitive body unit and the developing unit to an integrated position; and

and a coming-off preventing portion that restricts a relative movement between the photosensitive body unit and the developing unit in the axial direction so as to be able to be released when the fitting portion is fitted.

2. A process cartridge according to claim 1,

the assembly guide is engaged in a rotatable manner,

the photosensitive drum unit and the developing unit are rotatable in a direction in which the photosensitive drum is separated from and brought into contact with the developing roller with the assembly guide as a fulcrum in a state in which the assembly guide is engaged.

3. A process cartridge according to claim 1 or 2,

the assembly guide includes: a guide groove formed in one of the photosensitive body unit and the developing unit so as to extend in the axial direction; and a guide pin formed on the other of the photosensitive body unit and the developing unit and fitted into the guide groove.

4. A process cartridge according to any one of claims 1 to 3,

the assembly guide has a disengagement prevention portion that prevents engagement and disengagement of the assembly guide in a direction orthogonal to the axial direction when the fitting portion is fitted.

5. A process cartridge according to any one of claims 1 to 4,

the assembly guide is provided at an end portion on a side opposite to the photosensitive drum, of a surface where the photosensitive unit and the developing unit face each other.

6. A process cartridge according to any one of claims 1 to 5,

the assembly guide has an initial position specifying portion that specifies an initial position in the axial direction when the assembly guide is engaged.

7. A process cartridge according to any one of claims 1 to 6,

the coming-off preventing part includes: an elastically deformable locking piece formed on one of the photosensitive body unit and the developing unit; and a locking part formed on the other one of the photosensitive body unit and the developing unit and engaged with the locking piece.

8. A process cartridge according to any one of claims 1 to 7,

the image forming apparatus is provided with a stopper portion which prevents the developing unit from contacting the image forming region of the photosensitive drum when the photosensitive unit and the developing unit are integrated to operate.

9. A process cartridge according to claim 8,

the stopper portion is released from abutment immediately before the fitting portion is fitted.

10. An image forming apparatus is characterized by comprising:

a process cartridge according to any one of claims 1 to 9; and

and a device main body having a cartridge mounting portion to which the process cartridge is detachably mounted.

Technical Field

The present invention relates to a process cartridge and an image forming apparatus including the process cartridge, and more particularly, to a process cartridge in which a photosensitive unit including a photosensitive drum and a developing unit including a developing roller are separably integrated and are detachable from an apparatus main body of the image forming apparatus in an integrated state, and an image forming apparatus including the process cartridge.

Background

An example of a conventional image forming apparatus is disclosed in patent document 1. The image forming apparatus of patent document 1 includes: a process cartridge is detachable from a main body. The process cartridge is configured such that at least a photosensitive body unit for holding a photosensitive body and a developing unit are integrally formed and are attached to and detached from a main body in an integrated state. The main body is provided with a support portion for supporting the process cartridge detached from the main body so as not to contact the photoreceptor. Further, the process cartridge can be disassembled into the photosensitive body unit and the developing unit and reassembled on the support portion after being detached from the main body.

Disclosure of Invention

Technical problem to be solved by the invention

In the technique of patent document 1, the photosensitive body unit and the developing unit are integrated by screwing the side plate. Therefore, when the process cartridge is disassembled into the photosensitive body unit and the developing unit at the time of maintenance or the like, the screw needs to be detached using a screwdriver, which makes the disassembling work troublesome. And the assembly work is also troublesome. Therefore, the technique of patent document 1 has a problem in terms of maintenance because of a large workload on the user.

Accordingly, a main object of the present invention is to provide a novel process cartridge and an image forming apparatus including the process cartridge.

Another object of the present invention is to provide a process cartridge in which a photosensitive body unit and a developing unit can be integrated and separated by a simple operation, and an image forming apparatus including the process cartridge.

Technical solution for solving technical problem

The 1 st aspect of the present invention relates to a process cartridge in which a photosensitive unit including a photosensitive drum and a developing unit including a developing roller are separably integrated and are attached to and detached from an apparatus main body of an image forming apparatus in an integrated state. In the invention of claim 1, the photoreceptor unit and the developing unit include a fitting portion, an assembly guide, and a retaining portion. The fitting portion positions and integrates the photosensitive body unit and the developing unit by fitting them to each other in the axial direction of the photosensitive drum. The assembly guide is engaged so as to be slidable in the axial direction, and guides the photosensitive body unit and the developing unit to an integrated position, that is, a position where the fitting portions are fitted. The coming-off preventing portion regulates, in a releasable manner, relative movement of the photosensitive body unit and the developing unit in the axial direction when the fitting portion is fitted (in other words, coming-off prevention). In the process cartridge, for example, the photosensitive body unit is slid with respect to the developing unit in a state where the assembly guide is engaged, and the fitting portion is fitted to integrate the photosensitive body unit and the developing unit. In addition, the process cartridge is decomposed into a photoreceptor unit and a developing unit by performing the reverse operation.

According to the invention 1, the photosensitive body unit and the developing unit can be integrated and separated by a simple operation, and the operation load of the user can be reduced.

The 2 nd invention is an invention pertaining to the 1 st invention. In the invention of claim 2, the assembly guide is rotatably engaged with the photosensitive drum, and the photosensitive drum and the developing unit are rotatable in a direction of separating and contacting the photosensitive drum and the developing roller with the assembly guide as a fulcrum in a state where the assembly guide is engaged with the photosensitive drum and the developing roller.

The 3 rd invention is an invention pertaining to the 1 st or 2 nd invention. In the invention of claim 3, the assembly guide includes: a guide groove formed in one of the photosensitive body unit and the developing unit, and a guide pin formed in the other. The guide groove is formed to extend in the axial direction of the photosensitive drum, and the guide pin is slidably fitted in the guide groove.

The 4 th invention is an invention pertaining to any of the 1 st to 3 rd inventions. In the 4 th invention, the assembly guide has a disengagement preventing portion. The disengagement preventing portion prevents engagement and disengagement of the assembly guide in a direction orthogonal to the axial direction of the photosensitive drum when the fitting portion is fitted, in other words, when the photosensitive unit and the developing unit are integrated.

The 5 th invention is an invention pertaining to any of the 1 st to 4 th inventions. In the 5 th invention, the assembly guide is provided at an end portion on the opposite side of the surface of the photosensitive body unit and the developing unit from the photosensitive drum, in other words, at a position apart from the photosensitive drum.

The 6 th invention is an invention pertaining to any of the 1 st to 5 th inventions. In the 6 th aspect of the present invention, the assembly guide includes an initial position determining portion. The initial position specifying unit specifies an initial position of the assembly guide in the axial direction of the photosensitive drum when the assembly guide is engaged.

The 7 th invention is an invention pertaining to any of the 1 st to 6 th inventions. In the 7 th aspect of the present invention, the retaining portion includes: a locking piece formed on one of the photosensitive body unit and the developing unit, and a locking part formed on the other. The engaging piece is formed to be elastically deformable, and is elastically deformed, so that the engagement with the engaging portion can be released.

The 8 th invention is an invention pertaining to any of the 1 st to the 7 th inventions. In the 8 th aspect of the present invention, at least one of the photoreceptor unit and the developing unit includes: and a stopper portion for preventing the developing unit from contacting the image forming region of the photosensitive drum when the photosensitive unit and the developing unit are operated integrally.

The 9 th invention is an invention pertaining to the 8 th invention. In the 9 th aspect of the present invention, the stopper portion is released from abutment immediately before the fitting of the fitting portion.

The 10 th aspect of the present invention is an image forming apparatus including: a process cartridge according to any one of claims 1 to 9, and an apparatus main body having a cartridge mounting portion to which the process cartridge is detachably mounted.

Effects of the invention

According to the present invention, the photosensitive body unit and the developing unit can be integrated and separated by a simple operation, and the operation load of a user can be reduced.

The above and other objects, features and advantages of the present invention will become more apparent from the detailed description of the embodiments to be described later with reference to the accompanying drawings.

Drawings

Fig. 1 is a schematic cross-sectional view showing an internal structure of an image forming apparatus including a process cartridge according to a first embodiment of the present invention.

Fig. 2 is a schematic diagram showing an apparatus main body of the process cartridge and the image forming apparatus.

Fig. 3 is a perspective view showing a process cartridge as a first embodiment of the present invention.

Fig. 4 is a schematic sectional view showing the process cartridge of fig. 3.

Fig. 5 is a perspective view showing a photosensitive unit provided in the process cartridge of fig. 3.

Fig. 6 is a front view showing the photosensitive body unit of fig. 5.

Fig. 7 is a left side view showing the photosensitive body unit of fig. 5.

Fig. 8 is a perspective view showing a developing unit provided in the process cartridge of fig. 3.

Fig. 9 is a front view showing the developing unit of fig. 8.

Fig. 10 is a right side view showing the developing unit of fig. 8.

Fig. 11 is a schematic view schematically showing an operation of integrating the developing unit and the photosensitive body unit.

Fig. 12 is a schematic view showing a front end portion of the process cartridge at the time of the operation of (C) of fig. 11.

Fig. 13 is a schematic view showing a rear end portion of the process cartridge in an integrated state.

Fig. 14 is a schematic view showing a front end portion of a process cartridge as a second embodiment of the present invention.

Detailed Description

[ first embodiment ]

Referring to fig. 1 and 2, a process cartridge 10 according to a first embodiment of the present invention is used in an image forming apparatus 100 for forming a multicolor or monochrome image on a sheet (recording medium) by an electrophotographic method. As described later in detail, the process cartridge 10 includes: the photosensitive unit 34 including the photosensitive drum 50 and the like and the developing unit 36 including the developing roller 56 and the like are attached to and detached from (inserted into) the apparatus main body 12 of the image forming apparatus 100 in the longitudinal direction thereof in a positioned and integrated state. In addition, the process cartridge 10 has a configuration that it can be separated from the photosensitive body unit 34 and the developing unit 36 by a simple operation in a state of being removed from the apparatus main body 12, and can be integrated by a simple operation.

First, a basic configuration of the image forming apparatus 100 will be schematically described. In this embodiment, the image forming apparatus 100 is a multifunction peripheral (MFP) having a copy function, a print function, a scanner function, a facsimile function, and the like.

In this specification, the front-back direction (depth direction) of image forming apparatus 100 and its components is defined with the surface of image forming apparatus 100 facing the standing position of the user, in other words, the surface on which the operation portion such as a touch panel is provided, as the front surface (front surface), and the left-right direction (lateral direction) of image forming apparatus 100 and its components is defined with reference to the state in which image forming apparatus 100 is viewed from the user.

As shown in fig. 1, the image forming apparatus 100 includes: the image reading apparatus includes an apparatus main body 12 including an image forming unit 30 and the like, and an image reading device 14 disposed above the apparatus main body.

The image reading apparatus 14 includes a document platen 16 formed of a transparent material. A document pressing cover 18 is openably and closably attached to an upper portion of the document platen 16 via a hinge or the like. The document pressing cover 18 is provided with an ADF (automatic document feeder) 24 that automatically feeds documents placed on the document placement tray 20 one by one to the image reading position 22. Although not shown, an operation portion such as a touch panel and operation buttons for receiving an input operation such as a print instruction from a user is provided on the front surface side of the document platen 16.

The image reading device 14 incorporates an image reading unit 26 including a light source, a plurality of mirrors, an imaging lens, a line sensor, and the like. The image reading unit 26 exposes the surface of the document with a light source, and guides the reflected light reflected from the surface of the document to the imaging lens by a plurality of mirrors. The reflected light is imaged on the light receiving element of the linear sensor by the imaging lens. The linear sensor detects the luminance and chromaticity of the reflected light formed on the light receiving element, and generates image data based on an image of the document surface. As the linear sensor, ccd (charge Coupled device), cis (contact image sensor), or the like can be used.

The apparatus main body 12 incorporates a control unit 28 including a CPU, a memory, and the like, an image forming unit 30, and the like. The control unit 28 transmits control signals to respective portions of the image forming apparatus 100 in response to an input operation or the like to an operation unit such as a touch panel, and causes the image forming apparatus 100 to perform various operations.

The image forming unit 30 includes an exposure unit 32, a photoreceptor unit 34, a developing unit 36, an intermediate transfer belt unit 38, a transfer roller 40, a fixing unit 42, and the like, forms an image on a sheet conveyed from a paper feed tray 44 or a manual paper feed tray 46, and discharges the image-formed sheet to a paper discharge tray 48. As image data for forming an image on a sheet, image data read by the image reading unit 26, image data transmitted from an external computer, or the like is used.

Here, the process cartridge 10 is configured such that two sub-units of the photosensitive unit 34 and the developing unit 36 are integrated so as to be separable from each other, and the sub-units are inserted into and removed from the cartridge mounting portion 80 (see fig. 2) from the front surface side of the apparatus main body 12 in a state where the sub-units are positioned and integrated.

The image data collected in the image forming apparatus 100 corresponds to a color image of four colors, namely, black (K), cyan (C), magenta (M), and yellow (Y). Therefore, four process cartridges 10 are attached to the apparatus main body 12 so as to form four latent images corresponding to the respective colors, and four image stations are formed by these four process cartridges. The four process cartridges 10 are arranged in a row in the horizontal direction along the traveling direction of the surface of the intermediate transfer belt 64.

The exposure unit 32 is configured as a Laser Scanning Unit (LSU) including a laser emitting unit, a mirror, and the like, and exposes the surface of the charged photosensitive drum 50 to form an electrostatic latent image corresponding to image data on the surface of the photosensitive drum 50. The laser beam emitted from the exposure unit 32 passes through a gap between assembly guides disposed at a front end portion and a rear end portion of the process cartridge 10, which will be described later, and reaches the photosensitive drum 50.

The photoreceptor unit 34 includes a photoreceptor drum 50, a charger 52, a cleaning unit 54, and the like. The photosensitive drum 50 is an electrostatic latent image carrier having a photosensitive layer formed on the surface of a conductive cylindrical base body, and is rotatable around an axis by a drive unit not shown. The charger 52 is a member for charging the surface of the photosensitive drum 50 at a predetermined potential. The cleaning unit 54 includes a cleaning blade or the like, and removes and collects the toner remaining on the surface of the photosensitive drum 50 after the transfer of the toner image to the intermediate transfer belt 64.

The developing unit 36 visualizes the electrostatic latent image formed on the surface of the photosensitive drum 50 with four-color (YMCK) toner (forms a toner image), and includes a developing roller 56 that supplies toner to the photosensitive drum 50, and conveying members 58 and 60. The developing roller 56 is disposed so as to be adjacent to and along the photosensitive drum 50, and is rotatable about an axis line by a driving unit not shown. Further, a developer including toner and carrier is accommodated in a developing case 62 of the developing unit 36, and the toner contained in the developer is supplied to the photosensitive drum 50 via the developing roller 56.

The intermediate transfer belt unit 38 includes an intermediate transfer belt 64, a drive roller 66, a driven roller 68, four intermediate transfer rollers 70, and the like, and is disposed above the photosensitive drums 50. The intermediate transfer belt 64 is provided so as to be in contact with the photosensitive drums 50, and toner images of the respective colors formed on the photosensitive drums 50 are sequentially superimposed on and transferred to the intermediate transfer belt 64 by the intermediate transfer rollers 70, thereby forming a multicolor toner image on the intermediate transfer belt 64. Further, a transfer roller 40 is disposed near the drive roller 66, and the toner image formed on the intermediate transfer belt 64 is transferred to the paper by the paper passing through the nip region between the intermediate transfer belt 64 and the transfer roller 40.

The fixing unit 42 includes a heat roller 72 and a pressure roller 74, and is disposed above the transfer roller 40. The heat roller 72 is set to a predetermined fixing temperature, and the toner image transferred to the paper is fused, mixed, and pressed by the paper passing through the nip region between the heat roller 72 and the pressure roller 74, thereby thermally fixing the toner image to the paper.

In the apparatus main body 12, a 1 st paper conveyance path L1 is formed for conveying the paper from the paper feed tray 44 or the manual paper feed tray 46 to the paper discharge tray 48 via the pickup roller 76, the transfer roller 40, and the fixing unit 42. In the case of duplex printing on paper, a 2 nd paper feed path L2 is formed for returning the paper, which has passed through the fixing unit 42 after completion of simplex printing, to the 1 st paper feed path L1 on the upstream side in the paper feed direction of the transfer roller 40. A plurality of conveying rollers 78 for assisting the sheet with a propelling force are appropriately provided in the 1 st sheet conveying path L1 and the 2 nd sheet conveying path L2.

When single-sided printing (image formation) is performed in the apparatus main body 12, the sheets placed on the sheet feed tray 44 or the manual feed tray 46 are guided one by one to the 1 st sheet conveyance path L1, and conveyed to the pickup roller 76 by the conveyance roller 78. Then, the leading end of the sheet is conveyed to the transfer roller 40 by the pickup roller 76 at a timing to match the leading end of the image information on the intermediate transfer belt 64, and a toner image is transferred onto the sheet. Thereafter, the unfixed toner on the sheet is fused and fixed by heat by passing through the fixing unit 42, and the sheet is discharged onto the discharge tray 48 via a conveying roller (discharge roller) 78.

On the other hand, when double-sided printing is performed, when the rear end of the sheet having passed through the fixing unit 42 after single-sided printing has ended reaches the conveying roller 78 near the discharge tray 48, the conveying roller 78 is reversed, and the sheet is reversely moved and guided to the 2 nd sheet conveying path L2. The sheet guided to the 2 nd sheet conveyance path L2 is conveyed on the 2 nd sheet conveyance path L2 and guided to the 1 st sheet conveyance path L1 at the upstream side of the pickup roller 76 in the sheet conveyance direction. At this time, since the front and back of the sheet are reversed, the sheet passes through the transfer roller 40 and the fixing unit 42, and printing is performed on the back surface of the sheet.

Next, the structure of the process cartridge 10 will be explained. As shown in fig. 3 and 4, the process cartridge 10 is configured by detachably integrating the photosensitive unit 34 and the developing unit 36. The photosensitive unit 34 and the developing unit 36 are attached to and detached from a cartridge mounting portion 80 (see fig. 2) of the apparatus main body 12 in a positioned and integrated state. In this way, the photosensitive unit 34 and the developing unit 36 are attached and detached in a state integrated in advance, and thus the apparatus main body 12 can be downsized. This is because, in an image forming apparatus of a type in which the photosensitive drum unit and the developing unit are separately attached to the apparatus main body, the developing unit needs to be inserted and removed with a guide space secured between the developing unit and the photosensitive drum in order to prevent damage to the photosensitive drum, and therefore, the apparatus main body is increased in size, and the developing unit is attached and detached in an integrated state as in this embodiment, thereby eliminating the need for a guide space.

However, considering the maintainability, etc., it is preferable that the process cartridge 10 be separated from the photosensitive unit 34 and the developing unit 36 by a simple operation and be integrated by a simple operation. Therefore, the process cartridge 10 of the first embodiment adopts the following configuration. That is, the photosensitive unit 34 and the developing unit 36 constituting the process cartridge 10 are provided with a fitting portion, an assembly guide, a stopper portion, and the like, and the process cartridge 10 can be assembled and disassembled by a simple operation. The following description will be specifically made.

Referring to fig. 5 to 7 together with fig. 4, as described above, the photosensitive drum unit 34 includes the photosensitive drum 50, the charger 52, the cleaning unit 54, and the like, and these are integrally held by the photosensitive body frame 110 in a predetermined arrangement. In this embodiment, the photosensitive drum 50 is arranged to extend in the front-rear direction at an upper end portion of a surface side (left surface side) opposed to the developing unit 36. At this time, the photosensitive drum 50 is held by the photosensitive body frame 110 so that the upper left half is exposed. The charger 52 is disposed below the photosensitive drum 50, and the cleaning unit 54 is disposed on the right side of the photosensitive drum 50.

The photosensitive drum frame 110 includes a front wall 112 and a rear wall 114, and both ends of the drum shaft 50a of the photosensitive drum 50 are rotatably supported by bearings provided on the front wall 112 and the rear wall 114. Here, the front end of the drum shaft 50a projects forward from the front wall 112. Further, an extending portion extending leftward from the upper portion is formed in the rear wall 114, and a rear receiving portion 116 into which the rear end portion of the roller shaft 56a of the developing roller 56 is fitted is formed in the extending portion. The front end portion and the rear end portion 116 of the drum shaft 50a are used as a fitting portion for positioning and integrating the photosensitive body unit 34 with respect to the developing unit 36, together with a front end portion 134 and a rear end portion of the roller shaft 56a, which will be described later.

Further, in the photosensitive drum frame 110, a guide pin 118 is formed at a lower end portion (end portion on the opposite side of the photosensitive drum 50) of a surface (left surface) facing the developing unit 36. The guide pins 118 are formed in a cylindrical shape extending in the front-rear direction (axial direction of the photosensitive drum 50), and are disposed one at each of the front end portion and the rear end portion of the photosensitive body frame 110. The guide pin 118 is used as an assembly guide for guiding the photosensitive unit 34 to a position where the photosensitive unit 36 is integrated, together with a guide groove 136 of the developing housing 62, which will be described later.

Further, a locking portion 120 that engages with a locking piece 142 of the developing housing 62 described later is formed on the upper surface of the rear wall 114 of the photoreceptor frame 110. The locking portion 120 is formed in a triangular projection shape in which a rear surface is a vertical surface and a front surface is an inclined surface. The locking portion 120 and the locking piece 142 function as a retaining portion that retains the photosensitive body unit 34 and the developing unit 36 at an integrated position by restricting the backward relative movement (separation) of the unit 34 with respect to the developing unit 36.

Further, a small protrusion 122 extending in the front-rear direction is formed on the left side surface of the front wall 112 of the photoreceptor frame 110. The small projections 122 function as stoppers for preventing the developing unit 36 from coming into contact with the image forming area of the photosensitive drum 50 when the process cartridge 10 is assembled (in other words, when the photosensitive body unit 34 and the developing unit 36 are operated integrally by fitting the fitting portions) together with small projections 144 and 146 of the developing case 62 described later.

Referring to fig. 8 to 10 together with fig. 4, the developing unit 36 includes a developing roller 56, a 1 st conveying member 58, a 2 nd conveying member 60, and the like, and a doctor blade and the like, and these are integrally held by a developing casing 62 in a predetermined arrangement. To simplify the description, the 1 st conveying member 58 and the 2 nd conveying member 60 are provided in parallel with their respective rotation axes inside the developing housing 62, and the developer in which the toner and the carrier are mixed is stored. The 1 st conveyance member 58 and the 2 nd conveyance member 60 are helical screws having helical blades formed on the outer peripheral surfaces of cylindrical rotary shafts (screw shafts). Further, a developing roller 56 is disposed above the 2 nd conveying member 60 in the developing casing 62. The developing roller 56 is a magnetic roller that functions as a developer carrier, is arranged in parallel with the photosensitive drum 50, and is disposed so that the outer peripheral surfaces thereof are close to each other. The interval (DSD) between the photosensitive drum 50 and the developing roller 56 is set to 0.4mm, for example.

The developing housing 62 includes a front frame 130 and a rear frame 132, and both end portions of the roller shaft 56a of the developing roller 56 are rotatably supported by bearings provided in the front frame 130 and the rear frame 132. Here, the rear end of the roller shaft 56a protrudes rearward from the rear frame 132. Further, an extending portion extending rightward from the upper portion is formed in the front frame 130, and a front receiving portion 134 into which the front end portion of the drum shaft 50a is fitted is formed in the extending portion. As described above, the front receiving portion 134 and the rear end portion of the roller shaft 56a function as a fitting portion together with the front end portion of the drum shaft 50a and the rear receiving portion 116. The fitting portions, that is, the rear end portions of the front receiving portion 134 and the roller shaft 56a, and the front end portion of the drum shaft 50a and the rear receiving portion 116 are fitted in the front-rear direction.

Further, in the developing housing 62, a guide groove 136 that opens to the right side and extends in the front-rear direction is formed at a lower end portion of a surface (right surface) facing the photosensitive body unit 34. The guide grooves 136 are disposed one by one at positions corresponding to the guide pins 118, in other words, at the front end portion and the rear end portion of the developing housing 62, and are engaged with the guide pins 118 so as to be slidable in the front-rear direction. In addition, in this embodiment, the guide groove 136 is formed so that the width in the vertical direction gradually increases toward the open end side (right side). As a result, the guide pin 118 can be rotated in the circumferential direction thereof in a state where the guide pin 118 is engaged with the guide groove 136. As described above, the guide groove 136 functions as an assembly guide together with the guide pin 118. The photosensitive unit 34 is slidable in the front-rear direction with respect to the developing unit 36 in a state where the assembly guide (in other words, the guide pin 118 and the guide groove 136) is engaged, and is rotatable in a direction of separating and contacting the photosensitive drum 50 and the developing roller 56 with the assembly guide as a fulcrum.

Further, a separation preventing portion 138 having an elongated hole shape is formed at the tip end of each guide groove 136. The disengagement preventing portion 138 prevents the engagement and disengagement of the assembly guide in the left-right direction when the fitting portion is fitted, by inserting the guide pin 118. The disengagement preventing portion 138 may prevent both the units 34 and 36 from rotating. However, the disengagement prevention portion 138 is preferably a loose hole larger than the outer diameter of the guide pin 118. This is because the positions of the two units 34 and 36 are determined by the fitting portions (the shaft bodies 50a and 56a), and therefore, if the units are also positioned in the disengagement preventing portion 138, there is a possibility that the units cannot be assembled. For example, in the case where both the coupling of the developing unit 36 and the coupling of the cleaning member of the photosensitive drum unit 34 are intended to improve the positional accuracy of the couplings with respect to the apparatus main body 12, the disengagement preventing portion 138 is formed as a loose hole so as to be slightly rotatable between the both units 34, 36 when the process cartridge 10 is inserted and removed, and it is desirable that the complete rotation preventing member of the both units 34, 36 is provided in the apparatus main body 12.

Further, a flat plate-like initial position regulation portion 140 that partitions the guide groove 136 is formed at the rear end portion of the front guide groove 136. The initial position specifying unit 140 specifies the initial position of the assembly guide (and both units 34 and 36) in the front-rear direction when the assembly guide is engaged.

An elastically deformable locking piece 142 is formed to project rearward on the upper portion of the rear frame 132 of the developing casing 62. The locking piece 142 has an engaging hole 142a that engages with the locking portion 120 of the photoreceptor frame 110, and an inclined portion 142b inclined obliquely upward is formed at the rear end portion thereof. As described above, the locking piece 142 functions as a stopper portion for restricting the backward relative movement of the photosensitive body unit 34 with respect to the developing unit 36, together with the locking portion 120. The retaining portion is automatically engaged with the process cartridge 10 in accordance with the assembling operation. Further, the retaining portion can easily perform engagement release (fixation release) by elastically deforming the locking piece 142. At this time, since the inclined portion 142b is formed in the locking piece 142, the user can easily catch the finger, and thus the operability of the engagement release is improved. Further, by integrally molding the locking piece 142 in the developing housing 62, the front-rear direction positions of the two units 34, 36 can be fixed without increasing the number of components.

Further, small protrusions 144, 146 extending in the vertical direction are formed on the right side surfaces of the front frame 130 and the rear frame 132 of the developing casing 62. As described above, the small protrusions 144, 146 function as stoppers for preventing the developing unit 36 from contacting the image forming area of the photosensitive drum 50 together with the small protrusion 122 of the photosensitive body frame 110. The protruding height of the stopper portions ( small protrusions 122, 144, 146) is set to 0.3 to 0.5mm from the photosensitive drum 50 to the developing roller 56.

When the photosensitive unit 34 is slid with respect to the developing unit 36, the small projection 144 of the front frame 130 abuts against the small projection 122 of the photosensitive body frame 110 (see fig. 12). On the other hand, the small projection 146 of the rear frame 132 abuts on a position outside the image forming region of the rear end portion of the photosensitive drum 50 (specifically, outside the cleaning blade provided in the cleaning unit 54). The small projection 146 of the rear frame 132 is brought into contact with the rear end of the photosensitive drum 50, whereby the developing housing 62 can be downsized. Even if the photosensitive drum 50 is damaged by contact with the small protrusions 146, the image quality is not affected outside the image forming region, and thus, image failure due to vibration of the cleaning blade caused by the damage does not occur. However, the developing housing 62 may be extended rearward to prevent collision between the developing housing 62 and the photoreceptor frame 110.

The stopper portion is released from contact with the fitting portion immediately before fitting. That is, in the state where the fitting portions are fitted, the small protrusions 144 of the front frame 130 enter the gap between the front wall 112 and the photosensitive drum 50, and the small protrusions 146 of the rear frame 132 enter the gap between the rear wall 114 and the photosensitive drum 50. This prevents the engaging portion from being difficult to engage (becoming hard to insert) due to the abutment of the stopper portion being hindered. Further, it is possible to avoid a trouble that the DSD is affected or vibration is transmitted during image formation.

Next, with reference to fig. 11, the operation of the process cartridge 10 assembled by integrating the photosensitive unit 34 and the developing unit 36 will be described.

When integrating the photosensitive unit 34 and the developing unit 36, first, as shown in fig. 11 (a), the user brings the developing unit 36 and the photosensitive unit 34 close to each other and engages the assembly guide. That is, the guide pin 118 engages with the guide groove 136. At this time, the initial position determining portion 140 is formed in the front guide groove 136, thereby preventing the position of the photosensitive unit 34 and the developing unit 36 from being shifted in the front-rear direction. Further, since the assembly guide is disposed at the end opposite to the photosensitive drum 50, in other words, at a position away from the photosensitive drum 50, the assembly guide is easily visually recognized when engaged, and the operability is improved.

Next, as shown in fig. 11 (B), in a state where the guide groove 136 and the guide pin 118 are engaged, the photosensitive drum unit 34 is rotated in a direction in which the photosensitive drum 50 approaches the developing roller 56 with these rotation fulcrums until the stoppers abut against each other (see fig. 12). At this time, the initial position determining section 140 prevents positional displacement in the front-rear direction, and the stoppers properly abut against each other, thereby preventing the photosensitive drum 50 from being erroneously damaged.

Next, as shown in fig. 11 (C), the photosensitive unit 34 is slid forward relative to the developing unit 36 until the fitting portions are fitted, that is, the front end portion of the drum shaft 50a is inserted into the front receiving portion 134 and the rear end portion of the roller shaft 56a is inserted into the rear receiving portion 116.

Thus, as shown in fig. 11 (D), the photosensitive body unit 34 and the developing unit 36 are integrated in a positioned state. At this time, the guide pin 118 is inserted into the disengagement preventing portion 138, so that the engagement and disengagement of the assembly guide in the left-right direction are prevented, and the units 34 and 36 cannot be rotated. As shown in fig. 13, the locking piece 142 engages with the locking portion 120, thereby restricting the backward movement (falling-off) of the photosensitive body unit 34 with respect to the developing unit 36.

In this way, the process cartridge 10 can be integrated by a simple operation of engaging the assembly guides with each other, rotating the photosensitive body unit 34 relative to the developing unit 36, and then sliding. In this integrated state, the DSD is accurately stabilized because the front side and the rear side are determined by one element (the front frame 130 and the rear wall 114). Further, the assembly guide is disposed at a position away from the photosensitive drum 50, so that the positioning accuracy of both units 34 and 36 can be improved.

In addition, the process cartridge 10 can be easily disassembled from the photosensitive body unit 34 and the developing unit 36 by performing the reverse operation to that at the time of assembly. That is, in a state where the engagement of the retaining portion is released by elastically deforming the locking piece 142, the photosensitive body unit 34 may be slid toward the rear side with respect to the developing unit 36, and then the photosensitive body unit 34 may be rotated to release the engagement of the assembly guide. In this case, the assembly guide functions as a disassembly guide.

As described above, according to the first embodiment, since the assembly guide for guiding the photosensitive body unit 34 and the developing unit 36 to the integrated position is provided, the photosensitive body unit 34 and the developing unit 36 can be integrated and separated by a simple operation. Therefore, the operation load of the user can be reduced.

In the first embodiment described above, the photosensitive drum unit 34 is rotated relative to the developing unit 36 with the assembly guide as a rotation fulcrum, but this rotation operation is not necessarily required. However, the workability at the time of assembly is improved by engaging the assembly guide first.

[ second embodiment ]

Next, a process cartridge 10 as a second embodiment of the present invention will be explained. In the second embodiment, the separation preventing portions provided in the photosensitive body unit 34 and the developing unit 36 are configured, but the present invention is different from the first embodiment. The same applies to other portions, and therefore, the description overlapping with the first embodiment described above is omitted or simplified.

As shown in fig. 14, in the second embodiment, the unit forming the locking portion 120 and the locking piece 142 and the position thereof are reversed from those of the first embodiment. That is, the locking portion 120 is formed on the front frame 130 of the developing unit 36, and the locking piece 142 that can elastically deform is formed on the front wall 112 of the photosensitive unit 34.

In the second embodiment, the same operational effects as in the first embodiment are obtained, and the photosensitive body unit 34 and the developing unit 36 can be integrated and separated by a simple operation, so that the operational load on the user can be reduced.

In each of the above embodiments, a multifunction peripheral in which a copying machine, a facsimile, a printer, and the like are combined is exemplified as the image forming apparatus 100, but the image forming apparatus 100 may be any of a copying machine, a facsimile, a printer, and the like, or a multifunction peripheral in which at least two of them are combined. Further, image forming apparatus 100 may be a monochrome machine.

In addition, although the image forming apparatus 100 using the developer composed of two components, i.e., the toner and the carrier, has been described in the above embodiments, the present invention can also be applied to an image forming apparatus using a one-component developer. The configuration of the process cartridge 10 (the photosensitive body unit 34 and the developing unit 36), particularly the specific configuration of the fitting portion, the assembly guide, the retaining portion, the stopper portion, and the like, is not limited to the configuration adopted in each of the above embodiments, and can be appropriately changed.

The specific numerical values and element shapes listed above are simple examples, and can be changed as needed according to the specifications of the product and the like.

Description of the figures

10 … processing box

12 … device body

14 … image reading device

26 … image reading unit

30 … image forming part

34 … photosensitive body unit

36 … developer unit

50a, 56a, 116, 134 … fitting part

100 … image forming apparatus

118. 136 … Assembly guide

120. 142 … anti-drop part