HK1142692B - Process cartridge electrophotographic image forming apparatus - Google Patents

Description

Process cartridge and electrophotographic image forming apparatus

Technical Field

The present invention relates to a process cartridge composed of an electrophotographic photosensitive drum and a developing roller (which processes the photosensitive drum), and particularly to a process cartridge whose electrophotographic photosensitive drum and developing roller can be disposed in contact with each other or separated from each other. The present invention also relates to an electrophotographic image forming apparatus employing the above process cartridge.

Background

In recent years, a process cartridge system has come to be widely used in the technical field of image forming apparatuses using an electrophotographic image forming method. The process cartridge system is one of electrophotographic image forming systems. It uses a cartridge in which an electrophotographic photosensitive drum and a developing roller (i.e., a roller for processing the electrophotographic photosensitive drum) are integrally provided so that they can be removably mounted in the main assembly of an image forming apparatus. Thus, the use of the process cartridge system makes it possible for a user to maintain the electrophotographic image forming apparatus without relying on a service person. This is also the reason why the process cartridge system has started to be widely used in the electrophotographic image forming apparatus technical field.

The process cartridge is structured such that its developing roller is kept pressed against its electrophotographic photosensitive drum by applying a preset amount of pressure to keep the developing roller in contact with the photosensitive drum at the time of image formation. In a so-called contact development method (i.e., a development method in which a development roller is placed in contact with a photosensitive drum to develop a latent image on the photosensitive drum), an elastic layer of the development roller is kept pressed against the peripheral surface of the photosensitive drum, thereby maintaining a preset amount of contact pressure between the peripheral surface of the development roller and the peripheral surface of the photosensitive drum.

Therefore, if the process cartridge is left unused for a long time in the main assembly of the image forming apparatus, the elastic layer of the developing roller is sometimes deformed. Thus, if the image forming apparatus is used for the first time after the process cartridge has been left unused for a long time, there is a possibility that the latent image will be developed unevenly. Further, in the case of a so-called contact development method, the developing roller contacts the photosensitive drum during development. Therefore, the developer is sometimes transferred from the developing roller to the position of the peripheral surface of the photosensitive drum (the developer should not adhere thereto). Further, the photosensitive drum and the developing roller rotate in contact with each other not only during development but also during other processes other than development. Therefore, the so-called contact development method exacerbates the deterioration of the photosensitive drum, the developing roller, and the developer.

One solution to the above problem is proposed in japanese laid-open patent application No. 2003-167499. According to this patent application, an image forming apparatus is provided with a mechanism for acting on a process cartridge to separate an electrophotographic photosensitive drum and a developing roller from each other when an image is not actually formed (patent document 1).

In the case of the image forming apparatus proposed in patent document 1, the structure of its main assembly is such that four process cartridges are removably mountable in the main assembly. Each cartridge is composed of a photosensitive member unit and a developing unit. The photosensitive member unit has a photosensitive member. The developing unit supports the developing roller and is connected to the photosensitive member unit such that it is rotationally movable relative to the photosensitive member unit. Further, the main assembly of the image forming apparatus is provided with a separation sheet, and the process cartridge is provided with a force receiving portion. As the separation sheet moves, the force receiving portion receives a force from the separation sheet, causing the developing unit to move relative to the photosensitive member unit. As a result, the developing roller in contact with the photosensitive drum is separated from the photosensitive drum.

According to the related art, a force receiving portion (i.e., a portion that receives a force for separating the developing roller and the photosensitive member from each other) remains protruding from an outer contour of the developing unit. Therefore, the force receiving portion is easily damaged when the process cartridge is operated by a user or when the process cartridge is carried separately. Further, the presence of the above-described force receiving portion has been one of the main problems to be faced when there is an effort to reduce the size of a process cartridge having a structure in which an electrophotographic photosensitive member and a developing roller can be placed in contact with or separated from each other, and an effort to reduce the size of an image forming apparatus main assembly into which such a process cartridge as described above can be removably mounted.

Disclosure of Invention

A primary object of the present invention is to provide a process cartridge, of which an electrophotographic photosensitive drum and a developing roller can be disposed in contact with or separated from each other, and which is significantly smaller in size than the process cartridge according to the related art; and to provide an electrophotographic image forming apparatus compatible with a process cartridge according to the present invention, which is removably mountable, and having a size significantly smaller than that of the related-art electrophotographic image forming apparatus.

Another object of the present invention is to provide a process cartridge of which an electrophotographic photosensitive member and a developing roller can be disposed in contact with or separated from each other, and a developing unit moving force receiving portion is less likely to be damaged when the process cartridge is operated by a user or transported separately, as compared with the process cartridge of the related art.

These and other objects, features and advantages of the present invention will become more apparent upon a study of the following description of the preferred embodiments of the invention taken in conjunction with the accompanying drawings.

Drawings

Fig. 1 is a schematic sectional view of an electrophotographic image forming apparatus in a first embodiment of the present invention, showing the general structure of the apparatus.

Fig. 2 is a schematic sectional view of a process cartridge in a first embodiment of the present invention.

Fig. 3 is a schematic sectional view of an electrophotographic image forming apparatus in the first embodiment of the present invention, showing the general structure of the apparatus.

Fig. 4 is another schematic cross-sectional view of an electrophotographic image forming apparatus in the first embodiment of the present invention, showing how a process cartridge in the apparatus is replaced.

Fig. 5 is a schematic sectional view of one process cartridge and its vicinity in the electrophotographic image forming apparatus in the first embodiment of the present invention, the view being on a plane perpendicular to the axis of the photosensitive drum.

Fig. 6 is a schematic sectional view of a process cartridge in a first embodiment of the present invention, showing the movement of structural elements of the cartridge, which is associated with the mounting operation of the process cartridge into the apparatus main assembly.

Fig. 7 is a schematic side view (as viewed from the side thereof receiving the cartridge driving force) of a process cartridge, which is being mounted into the apparatus main assembly, in the first embodiment of the present invention, showing the movement of structural members of the cartridge, which is associated with the mounting operation of the process cartridge into the apparatus main assembly.

Fig. 8 is also a schematic side view (as viewed from the side thereof receiving the cartridge driving force) of the process cartridge, which is being mounted into the apparatus main assembly, in the first embodiment of the present invention, showing the movement of the structural member of the cartridge, which is associated with the mounting operation of the process cartridge into the apparatus main assembly.

Fig. 9 is an exploded perspective view of the process cartridge in the first embodiment of the present invention.

FIG. 10(a) is a perspective view of a process cartridge in the first embodiment of the present invention, which is taken from the side from which the cartridge is driven; and fig. 10(b) is a perspective view of the process cartridge in the first embodiment of the present invention, and is seen from the side opposite to the side on which the cartridge is driven.

FIG. 11 is a perspective view of the process cartridge in the first embodiment of the present invention, which is taken from the side from which the cartridge is driven.

Fig. 12 is a schematic view of a process cartridge in a second embodiment of the present invention, showing the movement of structural elements of the cartridge.

Fig. 13 is an exploded perspective view of a process cartridge in a second embodiment of the present invention.

Fig. 14 is a schematic view of a process cartridge in a third embodiment of the present invention, showing the movement of structural elements of the cartridge, which is associated with the mounting operation of the process cartridge to the apparatus main assembly.

Fig. 15 is an exploded perspective view of a process cartridge in a third embodiment of the present invention.

Fig. 16 is a schematic view of a cartridge tray guide hole of the electrophotographic image forming apparatus in the first embodiment of the present invention.

Fig. 17 is a partially cut-away perspective view of an electrophotographic image forming apparatus in a first embodiment of the present invention.

Fig. 18 is a schematic view of the pressing member and elements associated with the operation of the pressing member in the first embodiment of the present invention, showing the movement of the pressing member.

Fig. 19 is a schematic view of the first force application member and elements associated with the operation of the first force application member in the first embodiment of the present invention, showing the operation of the first force application member.

Fig. 20 is a perspective view of a force receiving device of the process cartridge in the first embodiment of the present invention.

Fig. 21 is a schematic view of the process cartridge in the first embodiment of the present invention, in which the second force receiving member of the process cartridge has just been moved by the second force application member of the cartridge.

Detailed Description

(example 1)

The process cartridge and the electrophotographic image forming apparatus in this preferred embodiment of the present invention will be described below with reference to fig. 1 to 4.

Fig. 1 is a schematic sectional view of an electrophotographic image forming apparatus 100 (which will be hereinafter simply referred to as apparatus main assembly) in which a plurality of (four) process cartridges 50y, 50m, 50c, 50k (which may be hereinafter simply referred to as cartridges 50) have been removably mounted. The plurality of (four) cartridges 50 store yellow, magenta, cyan, and black toners (developers), one for each cartridge. Figure 2 is a schematic cross-sectional view of the cartridge itself. Fig. 3 and 4 are schematic cross-sectional views of the electrophotographic image forming apparatus in this embodiment, for illustrating how any one or more cartridges 50 are removed from the main assembly of the image forming apparatus.

(general construction of electrophotographic image Forming apparatus)

The electrophotographic image forming apparatus in this embodiment is structured to perform the following image forming operation. Referring to fig. 1, first, uniformly charged areas of the peripheral surfaces of the respective electrophotographic photosensitive drums (which will be hereinafter simply referred to as photosensitive drums) 30y, 30m, 30c, and 30k are scanned by a laser beam 11, which laser beam 11 is emitted from a laser scanner 10 provided to the apparatus main assembly 100 while being modulated in accordance with a pattern signal. As a result, an electrostatic latent image is generated on the outer peripheral surface of each photosensitive drum 30. The electrostatic latent image is developed into a visible image by the developing roller 42; a toner (developer) image is formed on the peripheral surface of the photosensitive drum 30. In other words, yellow, magenta, cyan, and black toner images are formed on the photosensitive drums 30y, 30m, 30c, and 30k, respectively. Then, these toner images are sequentially transferred onto the transfer belt 19 supported and stretched by the rollers 20 to 22 by the voltages applied to the transfer rollers 18y, 18m, 18c, and 18 k. Thereafter, the toner image on the transfer belt 19 is transferred onto the sheet of the recording medium P conveyed by the recording medium conveying roller 1 as a recording medium conveying device by the transfer roller 3. Then, the recording medium P is conveyed to a fixing unit 6, and the fixing unit 6 is composed of a driving roller and a fixing roller having an internal heater. In the fixing unit 6, heat and pressure are applied to the recording medium P and the toner image thereon. As a result, the toner image on the recording medium P is fixed to the recording medium P. Then, the recording medium P is discharged onto the conveyance tray 9 by the pair of discharge rollers 7.

(general construction of Process Cartridge)

The cartridge 50 in this embodiment will be described next with reference to fig. 1, 2 and 10. The plurality of (four) cartridges 50 in this embodiment are identical in structure although the colors of the stored toners are different. Therefore, the structure of the cartridge 50 will be explained with reference to the cartridge 50 y.

The cartridge 50y carries the photosensitive drum 30 and a process device that processes the photosensitive drum 30. The process devices in this embodiment are a charging roller 32, a developing roller 42, a blade 33, and the like, the charging roller 32 is a charging device for charging the photosensitive drum 30, the developing roller 42 is a developing device for developing the latent image formed on the photosensitive drum 30, and the blade 33 is a cleaning device for removing residual toner remaining on the peripheral surface of the photosensitive drum 30. The cartridge 50y is composed of the drum unit 31 and the developing unit 41.

(construction of Drum Unit)

Referring to fig. 2 and 10, the drum unit 31 includes the photosensitive drum 30 described above, a charging roller 32, and a blade 33. It also includes a waste toner storage portion 35, a drum unit frame 34, and side covers 36 and 37 (which will be simply referred to as covers hereinafter). Referring to fig. 9, one of the lengthwise ends of the photosensitive drum 30 is rotatably supported by the supporting portion 36b of the cover 36, and the other lengthwise end is rotatably supported by the supporting portion 37b of the cover 37, as shown in fig. 10(a) and 10 (b). The covers 36 and 37 are attached to the lengthwise ends of the drum unit main frame 34. Next, referring to fig. 10(b), the lengthwise end of the photosensitive drum 30 supported by the cover 36 is provided with a coupling member 30a for transmitting the driving force to the photosensitive drum 30. When the cartridge 50y is mounted into the apparatus main assembly 100, the coupling member 30a engages a first coupling member 105 (shown in fig. 4 and 7) of the apparatus main assembly 100. In this way, when a driving force is transmitted from a motor (not shown) carried by the apparatus main assembly 100 to the coupling member 30a, the photosensitive drum 30 rotates in a direction indicated by an arrow mark U in fig. 2. The charging roller 32 is supported by the drum unit main frame 34 such that the charging roller 32 rotates in contact with the photosensitive drum 30 by the rotation of the photosensitive drum 30. The blade 33 is also supported by the drum unit main frame 34 such that the blade 33 is held in contact with the outer peripheral surface of the photosensitive drum 30 with a preset amount of pressure between the blade 33 and the outer peripheral surface of the photosensitive drum 30. The covers 36 and 37 are provided with holes 36a (fig. 9) and 37a (fig. 10(b)) for supporting the developing unit 40 in such a manner that the developing unit 40 is rotatably movable relative to the drum unit 31.

(Structure of developing unit)

Referring to fig. 2 and 9, the developing unit 41 has the above-described developing roller 42. The developing unit 41 also has a developing blade 43, a developing unit main frame 48, a supporting unit 45, and a pair of side covers 46. The developing unit main frame 48 has a toner storage portion 49, and stores toner to be supplied to the developing roller 42 in the toner storage portion 49. The developing unit main frame 48 supports a developing blade 43 that adjusts the coverage thickness of the toner on the outer peripheral surface of the developing roller 42. Referring to fig. 9, the supporting unit 45 is fixedly attached to one lengthwise end of the developing unit main frame 48. The bearing unit 45 rotatably supports the developing roller 42, one lengthwise end portion of which has a developing roller gear 69. Further, the supporting unit 45 is provided with an intermediate gear 68, and the intermediate gear 68 transmits the driving force from the coupling member 67 to the developing roller gear 69. The cover 46 is firmly attached to the outside of the support unit 45 (in terms of the length direction of the support unit 45) in such a manner as to cover the coupling member 67 and the intermediate gear 68. Further, the cover 46 is provided with a cylindrical portion 46b protruding outward from the outer surface of the cover 46. The coupling member 67 is exposed through the hollow portion of the cylindrical portion 46 b. The apparatus main assembly 100 and the process cartridge 50y are structured such that: when the process cartridge 50y is mounted into the apparatus main assembly 100, the coupling portion 67a of the coupling member 67 engages a second coupling member 106 (which is illustrated in fig. 17) of the apparatus main assembly 100, thereby transmitting a driving force from a motor (not illustrated) carried by the apparatus main assembly 100 to the process cartridge 50 y.

(connection of developing Unit to Drum Unit)

Referring to fig. 9 to 11, the developing unit 41 and the drum unit 31 are connected in the following manner: first, at one end of the process cartridge 50y, the cylindrical portion 46b is fitted into the support hole 36 a. At the other end, a protrusion 48b protruding from the developing unit main frame 48 is fitted into the support hole 37 a. As a result, the developing unit 41 is connected to the drum unit 31 in such a manner that the developing unit 41 is rotationally movable relative to the drum unit 31. Next, referring to fig. 2, the developing unit 41 is held under pressure in a direction to be rotated about the axis of the cylindrical portion 46b by a pair of compression springs 95 (which are elastic members), so that the developing roller 42 is held in contact with the photosensitive drum 30. That is, the developing unit 41 is kept pressed in the direction indicated by the arrow mark G by the elastic force of the compression spring 95, generating the moment H acting in the direction of rotating the developing unit 41 around the cylindrical portion 46b and the projection 48 b. Thus, the developing roller 42 is kept in contact with the photosensitive drum 30 and there is a contact pressure between the developing roller 42 and the photosensitive drum 30 by a preset amount. The position at which the developing unit 41 is located when it is held in contact with the photosensitive drum 30 is referred to as a "contact position".

Referring to fig. 10(a), the compression spring 95 is located on the other side in this embodiment from the longitudinal direction end at which the coupling member 30a of the photosensitive drum 30 and the coupling member 67 that transmits the driving force to the developing roller gear 69 are located.

(force receiving device)

Referring to fig. 2, the cartridge 50y is provided with a force receiving means 90 for bringing the developing roller 42 and the photosensitive drum 30 in the apparatus main assembly 100 into contact with each other or separating them.

Referring to fig. 6 and 8, which are schematic side views of the cartridge 50y as viewed from the side from which the cartridge 50y is driven, wherein the cover 36 of the cartridge 50y has been removed, the force receiving device 90 is composed of a first force receiving member 71 and a second force receiving member 70. Before the cartridge 50y starts to be positioned in a preset manner relative to the apparatus main assembly 100, the second force receiving member 70 is held in its standby position, i.e., the position at which the second force receiving member 70 does not project beyond the outer contour of the cartridge 50y, as shown in fig. 10 (a). When the cartridge 50y enters the apparatus main assembly 100 in the direction indicated by an arrow mark Z2 (shown in fig. 1) by means of the cartridge tray 13 (to be described later), the cartridge 50y is positioned in the apparatus main assembly 100 by the cartridge positioning portion 101a of the apparatus main assembly 100. When the cartridge 50y is pressed against the cartridge positioning portion 101a, the first force receiving member 71 is pressed upward by a projection 180 (a member pressing the first force receiving member) of the apparatus main assembly 100, which will be described later. That is, the first force receiving member 71 receives the first external force from the protrusion 180. As a result, the second force receiving member 70 is moved away from its standby position, protruding outside the cartridge 50y, beyond the outer contour of the cartridge 50y, as shown in fig. 11.

Referring next to fig. 6, 7 and 9, when the cartridge 50y is held in the apparatus main assembly 100 by the positioning portions 101a to be accurately positioned (image forming position), the first force receiving member 71 is located below the second force receiving member 70. The first force receiving member 71 and the second force receiving member 70 are connected to each other. More specifically, the second force receiving member 70 is rotatably supported by its rotational shaft 70b and has an elongated hole 70 a. The top end portion (in the drawing) of the first force receiving member 71 is provided with a projection (connecting pin) which is fitted in the elongated hole of the second force receiving member 70. In this way, when a force is applied to the second force receiving member 70 by the first force receiving member 71, more specifically, by the projection (connecting pin) of the first force receiving member in the elongated hole 70a of the second force receiving member 70, the second force receiving member 70 is rotationally moved about the rotational shaft 70b thereof.

Referring to fig. 7, since the elongated hole 70a is located between the rotational shaft 70b and the force-receiving surface 70c, the distance h2 traveled by the second force receiving member 70 can be greater than the distance h1 (fig. 7) traveled by the first force receiving member 71 by appropriately setting the leverage ratio of the second force receiving member 70. Here, the distance by which the first force receiving member 71 and the second force receiving member 70 are moved is a distance measured in a vertical direction (that is, in parallel to a direction in which the force receiving member 71 is moved toward the force application member 60 (which will be described later)). That is, by adopting the above-described structural arrangement, the distance h2 by which the second force receiving member 70 is moved can be increased without increasing the projecting distance of the projection 180, so that it is thereby possible to reduce the size of the apparatus main assembly 100 shown in fig. 1. Incidentally, the force receiving device is movably supported by the cover 46.

(Cartridge tray of main assembly of electrophotographic image forming apparatus)

Next, the tray 13 in the form of a drawer will be explained.

Referring to fig. 4, the cartridge tray 13 is attached to the apparatus main assembly 100 in such a manner that: in implementation, it is horizontally and linearly movable relative to the apparatus main assembly 100. That is, the cartridge tray 13 can be pushed into the apparatus main assembly 100 or pulled out from the apparatus main assembly 100 in the direction indicated by the arrow mark Z2 or Z1, respectively. The apparatus main assembly 100 is structured such that: the cartridge tray 13 can be locked at an innermost position (image forming position in the apparatus main assembly 100 shown in fig. 1) and at an outermost position (cartridge replacement position shown in fig. 4, i.e., cartridge mounting or removing position, which is a farthest position at which the cartridge tray 13 can be pulled out). As shown in fig. 4, the cartridge 50 is mounted into the cartridge tray 13 by the operator in a direction indicated by an arrow mark C, which is substantially parallel to the direction of gravity. The cartridge tray 13 is structured such that: when these cartridges 50 are mounted into the cartridge tray 13, the cartridges 50 are arranged in tandem in a direction parallel to the movable direction of the cartridge tray 13, and the length direction of the cartridges 50 (which is parallel to the axes of the photosensitive drum 30 and the developing roller 42) is perpendicular to the movable direction of the cartridge tray 13. When the cartridge tray 13 is pushed into the apparatus main assembly 100, the cartridges 50 in the cartridge tray 13 enter the apparatus main assembly 100, and there is a preset amount of gap f2 (fig. 5) between the photosensitive drum 30 in each cartridge 50 and the intermediate transfer belt 19 located below the cartridge path in the apparatus main assembly 100. Then, when the cartridge tray 13 is moved to its innermost position in the apparatus main assembly 100, each cartridge 50 is correctly positioned in the apparatus main assembly 100 by a cartridge positioning portion 101a provided in the apparatus main assembly 100 (fig. 5 and 7). The cartridge positioning operation will be described in detail later. The user closes the door 12 after pushing the tray 13 all the way into the apparatus main assembly 100. Closing the door 12 ensures that each cartridge 50 is properly mounted in the apparatus main assembly 100. Therefore, such structural arrangement of the apparatus main assembly 100 and the cartridge 50 is superior in operability to that of the related art electrophotographic image forming apparatus in which the user is required to mount the cartridge 50 to the apparatus main assembly 100 separately.

Next, referring to fig. 1, 3, 4, and 17, the operation of the cartridge tray 13 will be described below. Fig. 17 does not show the cartridge 50 in order to make it easier to understand the operation of the cartridge tray 13.

The cartridge tray 13 is supported by a pair of tray support members 14 in the following manner: the cartridge tray 13 can be pulled out of the apparatus main assembly 100 while being held supported by the tray supporting member 14. The tray support member 14 is moved by the movement of the door 12, and the door 12 can be opened or closed by an operator (user). The door 12 is attached to the apparatus main assembly 100 such that it is rotatably movable about its rotational axis 12 a. The door 12 is rotatably movable between a position (closed position) to completely cover the opening 80 as shown in fig. 1 and a position (open position) to completely expose the opening 80 as shown in fig. 3.

When it is necessary to take out any one or more cartridges 50 in the apparatus main assembly 100, the door 12 is rotationally moved from the closed position to the open position. When the door 12 is rotationally moved, the pair of projections 15 (connecting pins) carried by the door 12 are moved clockwise about the rotational axis 12a while moving in the pair of elongated holes 14c carried by the tray supporting member 14 (one-to-one correspondence), moving from the bottom ends of the elongated holes 14c toward the top ends of the elongated holes 14c, as shown in fig. 3. As a result, the tray supporting member 14 is moved in the direction indicated by the arrow mark Z1 by the projection 15. As shown in fig. 4, when the tray supporting members 14 are moved in the above-described direction, the projections 14d1 and 14d2 projecting from each tray supporting member 14 are guided by the guide holes 107 carried by the apparatus main assembly 100. Referring to fig. 16, each guide hole 107 has three sections, i.e., two horizontal sections 107a1 and 107a3, and one inclined section 107a 2. The inclined segment 107a2 extends obliquely upward from the horizontal segment 107a1 to the horizontal segment 107a 3. Therefore, when the door 12 moves from the closed position shown in fig. 1 to the open position shown in fig. 3, the protrusions 14d1 and 14d2 are guided by the guide hole 107, sequentially passing through the horizontal section 107a1, the inclined section 107a2, and the horizontal section 107a 3. Thus, the tray supporting member 14 is first moved in the direction indicated by the arrow mark Z1, and then moved in the direction indicated by the arrow mark Y1 (i.e., the direction away from the transfer belt 19). When the tray supporting member 14 moves all the way in the direction indicated by the arrow mark Y1, the cartridge tray 13 can be pulled out of the apparatus main assembly 100 through the opening 80 in the direction indicated by the arrow mark Z1, as shown in fig. 4. Fig. 17 is a partially cut-away perspective view of the image forming apparatus after the cartridge tray 13 has been pulled out from the apparatus main assembly 100 to its outermost position.

Next, a case where any one cartridge or a plurality of cartridges 50 is mounted into the apparatus main assembly 100 will be described. Referring to fig. 4, with the door 12 held at the open position, the cartridge tray 13 is pushed into the apparatus main assembly 100 through the opening 80 in the direction of arrow mark Z2. The door 12 is then moved to the closed position as shown in fig. 1. When the door 12 moves, each protrusion 15 of the door 12 moves in the counterclockwise direction about the rotation axis 12a while moving toward the bottom end 14c2 of the elongated hole 14c in the corresponding elongated hole 14c of the tray support member 14 as shown in fig. 1. Thus, the tray supporting member 14 is moved in the direction of the arrow mark Z2 by the pair of projections 15. Therefore, when the door 12 is moved to the closed position as shown in fig. 1, the protrusions 14d1 and 14d2 (fig. 4) are guided by the horizontal segment 107a1, the inclined segment 107a2, and the horizontal segment 107a3 in the listed order, as shown in fig. 16. Thus, the tray supporting member 14 is first moved in the direction of arrow mark Z2, and then moved in the direction of arrow mark Y2 (i.e., the direction of moving closer to the transfer belt 19), as shown in fig. 1.

(positioning of Process Cartridge with respect to the Main Assembly of the electrophotographic image Forming apparatus)

Next, referring to fig. 5, 17, the positioning of the cartridge 50 in the image apparatus main assembly 100 will be described. Referring to fig. 17, the apparatus main assembly 100 is provided with a plurality of pairs (four pairs in this embodiment) of cartridge positioning portions 101a for positioning the cartridge 50 relative to the apparatus main assembly 100. That is, in a direction parallel to the lengthwise direction of the cartridges 50, each cartridge magazine of the cartridge tray 13 is provided with a pair of cartridge positioning portions 101a, the cartridge positioning portions 101a being located at lengthwise direction ends of the respective cartridge magazines, one at each end, and the transfer belt 19 being located between these two cartridge positioning portions 101 a. Referring to fig. 18(a) and 18(b), above each tray supporting member 14, there is a pressing member 61(61y, 61m, 61c, and 61 k). Each pressing member 61 is provided with a hole 61d through which a pressing member supporting shaft 55 provided in the apparatus main assembly 100 is provided so as to rotatably support the pressing member 61.

Referring again to fig. 18(a) and 18(b), when the door is moved from the open position to the closed position (in the X direction), the pressing member 61 is moved in the direction indicated by the arrow Z, thereby pressing on the top surface of the drum unit main frame 34 as shown in fig. 20. Thus, the cartridge 50 is pressed in the direction indicated by the arrow mark P in fig. 7, so that the cartridge positioning portion 31b carried by the drum unit 31y comes into contact with the cartridge positioning portion 101a of the apparatus main assembly 100. As a result, the cartridge 50y is properly positioned in the apparatus main assembly 100. Similarly, the cartridges 50m, 50c, and 50k are appropriately positioned in the apparatus main assembly 100.

Further, when the cartridge 50 is lowered toward the positioning portion 101a by the movement of the door 12, the projection 180 of the apparatus main assembly 100 comes into contact with the force receiving portion 71c of the first force receiving member 71, which is the bottom of the cartridge 50. That is, the force receiving member 71 receives the force from the protrusion 180 from the bottom of the cartridge 50. In contrast, when the door 12 is moved (in the Y direction) from the closed position to the open position, the pressing member 61 is moved in the direction indicated by the arrow mark J. As a result, the pressing member 61 is separated from the top surface of the drum unit main frame 34 as shown in fig. 5.

(developing roller separating mechanism of main assembly of electrophotographic image forming apparatus)

Next, the operation of the first force application portion 60 will be described.

Referring to fig. 1, 3 and 19, in terms of the vertical direction of the apparatus main assembly 100, the urging member 60 is positioned such that: after the cartridge 50 is positioned, the urging member 60 is positioned above the cartridge 50. With respect to the axial direction of the photosensitive drum 30, the urging member 60 is positioned such that: which is capable of contacting the second force receiving member 70 at the respective lengthwise end of the cartridge 50.

The driving force is transmitted from the motor (mechanical power source) carried by the apparatus main assembly 100 to the gear 112 through the gear 111. When the driving force is transmitted to the gear 112, the gear 112 rotates in the direction indicated by the arrow mark L, thereby rotating the cam portion 112a integral with the gear 112 in the direction of the arrow L. The cam portion 112a is in contact with the moving force receiving portion 60b carried by the urging member 60. Therefore, when the cam portion 112a rotates, the moving force receiving portion 60B moves in the direction indicated by the arrow mark E or B.

Referring to fig. 19(a), when the urging member 60 is moved in the direction indicated by the arrow mark E, the rib 60y of the urging member 60 is separated from the second force receiving member 70 as shown in fig. 7, thereby allowing the developing roller 42 to contact the photosensitive drum 30. This position of the developing unit 41 (which allows the developing roller 42 to remain in contact with the photosensitive drum 30) will be referred to as a contact position.

Referring to fig. 19(B), when the force application member 60 is moved in the direction indicated by the arrow mark B, the rib 60y starts to contact the second force receiving member 70, so that the second force receiving member receives an external force (second external force) through the rib 60 y. Thus, the developing unit 41 rotates (rotationally moves) about the cylindrical portion 46b (rotational shaft), thereby separating the developing roller 42 from the photosensitive drum 30. This position of the developing unit 41 (which keeps the developing roller 42 separated from the photosensitive drum 30) will be referred to as a separation position.

Similarly, the urging member 60 is positioned above the path of the cartridge 50 (the path in which the cartridge 50 is moved into the apparatus main assembly 100 by the cartridge tray 13). The second force receiving member 70 is attached to the cartridge 50 in the following manner: the second force receiving member 70 is held in its standby position (fig. 5) before the cartridge 50 is moved into the apparatus main assembly 100. The force application member 60 can therefore be positioned significantly closer to the cartridge path than in the prior art, without the force application member 60 and the cartridge 50 interfering with each other during mounting of the cartridge 50, so that wasted space can be minimized, thereby making it possible to significantly reduce the size of the cartridge 50y in the lengthwise direction of the cartridge 50y (the axial direction of the photosensitive drum 30) and in the vertical direction of the apparatus main assembly 100. The urging member 60 will be described in more detail later.

(instructions for mounting the process cartridge to the main assembly of the electrophotographic image forming apparatus and force receiving means)

Next, the operation sequence from the mounting of the cartridge 50 to the apparatus main assembly 100 until the separation of the developing roller 42 from the photosensitive drum 30 will be described.

Referring to fig. 4, after the cartridge tray 13 is pulled out from the apparatus main assembly 100 to its outermost position, each cartridge 50 is mountable to or removable from the cartridge tray 13 in the vertical direction indicated by an arrow mark C.

After the cartridge 50 is mounted into the cartridge tray 13, the cartridge tray 13 will be moved into the apparatus main assembly 100 through the opening 80 in the direction indicated by the arrow Z2. That is, in this embodiment, each cartridge 50 is horizontally moved into the apparatus main assembly 100 in a direction intersecting (substantially perpendicular to) the axis of the photosensitive drum 30.

Referring to fig. 3, the cartridge 50y is mounted at the downstream end of the cartridge tray 13 in terms of the direction in which the cartridge tray 13 is moved into the apparatus main assembly 100. That is, the cartridge 50y moves from upstream to downstream below the ribs 60k, 60c, and 60m of the first force application member 60.

If the apparatus main assembly 100 and the cartridge 50y are structured such that the second force receiving member 70 remains projected when the cartridge 50y is moved into the apparatus main assembly 100, the pressing member 61 and the urging member 60 must be positioned significantly higher than their positioning in this embodiment. However, in this embodiment, the apparatus main assembly 100 and the cartridge 50y are structured such that the second force receiving member 70 is held in the above-described standby position at the time when the cartridge 50y is moved into the apparatus main assembly 100. Therefore, the pressing member 61 and the urging member 60 can be positioned as close as possible without considering the distance by which the second force receiving member 70 protrudes beyond the outer contour of the cartridge 50 y. In other words, the pressing member 61 and the urging member 60 can be positioned significantly closer to the path of the cartridge 50y, so that the size of the cartridge 50y in the direction parallel to the vertical direction of the apparatus main assembly 100 can be reduced as compared with the corresponding case of the related art process cartridge. Further, referring to fig. 20, the force receiving device 90, the pressing member 61, and the force application member 60 overlap in a direction parallel to the axis of the drum 30, thereby making it possible to reduce the size of the cartridge 50y in the length direction thereof.

Next, referring to fig. 5, the mechanism of the image forming apparatus in this embodiment is designed such that: when the cartridge tray 13 is moved into the apparatus main assembly 100, there is a gap f1 between the urging member 60 and the force receiving member 70, and a gap f2 between the photosensitive drum 30 and the transfer belt 19. Therefore, the cartridge 50 and the apparatus main assembly 100 do not interfere with each other when the cartridge 50 is mounted into the apparatus main assembly 100.

After the cartridge tray 13 is pushed all the way into the apparatus main assembly 100, the door 12 will be moved to the closed position as shown in fig. 1 and fig. 18 (b). When the door 12 is moved to the closed position, the tray support member 14 is moved toward the transfer belt 19 (the direction indicated by an arrow mark Y2). Hereinafter, the vertical component of the movement of the tray support member 14 in the direction indicated by the arrow mark Y2 will be referred to as a distance f 2. When the tray supporting member 14 moves in the direction indicated by the arrow mark Y2, the cartridges 50 move toward the transfer belt 19 with the movement of the tray supporting member 14, thereby causing the outer peripheral surfaces of the photosensitive drums 30 in the respective cartridges 50 to start to contact the surface of the transfer belt 19. By the time the peripheral surface of the photosensitive drum 30 comes into contact with the surface of the transfer belt 9, the distance f1 between the force receiving device 90 and the urging member 60 widens to the sum of the gaps f1 and f2, as shown in fig. 5.

Further, when the door 12 is moved to the closed position, the pressing member 61 is carried by the movement of the door 12, thereby pressing on the top surface of the drum unit main frame 34. Thus, the cartridge positioning portion 31b of each cartridge 50 contacts the cartridge positioning portion 101a of the apparatus main assembly 100. As a result, as shown in fig. 7, each cartridge 50 is correctly positioned with respect to the apparatus main assembly 100.

Further, the shaft 36d (shown in fig. 10) carried by the cover 36 of each cartridge 50 is engaged with the cartridge rotation stopper portion 13a (fig. 17) carried by the cartridge tray 13. Therefore, the cartridge 50 is prevented from further moving in the apparatus main assembly 100 in the direction indicated by the arrow mark a in fig. 1.

Referring next to fig. 6, the home position of the urging member 60 in this embodiment is set to a position where the urging member 60 keeps the developing roller 42 separated from the photosensitive drum 30. The reason is as follows. That is, when the image forming apparatus is not used for image formation after the cartridges 50 are mounted, each cartridge 50 is maintained in the state shown in fig. 8. That is, the force application member 60 has moved in the direction indicated by the arrow mark B, and the second force receiving member 70 has moved as far as possible by the rib 60 y. When the cartridge 50 is in this state, the photosensitive drum 30 and the developing roller 42 are kept separated from each other. In this state shown in fig. 8 (in which the photosensitive drum 30 and the developing roller 42 are kept separated from each other), the cartridge 50 is removed from the apparatus main assembly 100. In this way, when the cartridge 50 is mounted into the apparatus main assembly 100 next time, the urging member 60 is at the position shown in fig. 8. Therefore, when the cartridge 50 is mounted, the second force receiving member 70 comes into contact with the rib 60y because the second force receiving member 70 is not in its standby position as shown in fig. 6. Thus, the first force receiving member 71 is provided with an elastic portion 71b (which is formed as an integral part of the first force receiving member 71), as shown in fig. 6. Therefore, when the contact between the second force receiving member 70 and the rib 60y starts to interfere with the inward movement of the cartridge 50, the elastic portion 71b yields (is pressed), thereby preventing the force receiving device 90 from being damaged.

When the force application member 60 in the state shown in fig. 6 is moved in the direction indicated by the arrow mark E as shown in fig. 7, the second force receiving member 70 projects further outward from the cartridge 50y, thereby entering the path of the rib 60 y. This position of the second force receiving member 70, i.e. the position of the second force receiving member 70 in the path of the rib 60y, will be referred to as the outermost position (activated position). That is, when the second force receiving member 70 is in its outermost position, the second force receiving member 70 protrudes a distance greater than when the second force receiving member 70 is in the above-described standby position, as will be apparent. In order for the second force receiving member 70 to engage the force applying member 60, the protruding distance of the second force receiving member 70 at the outermost position must be greater than the sum of the gaps f1 and f 2. Further, the urging member 60 is operated during the period between the completion of the mounting of the cartridge 50 into the apparatus main assembly 100 and the start of the image forming operation.

Referring next to fig. 8, when the force application member 60 is moved in the direction indicated by the arrow mark B, the side surface 70c (the second force receiving portion of the second force receiving member 70) receives the external force (the second external force) through the rib 60y3 because the second force receiving member 70 (the side surface 70c) is in the path of the force application member 60. Accordingly, the developing unit 41 is rotationally moved about its rotational axis 46b (shaft), thereby separating the developing roller 42 from the photosensitive drum 30 by a distance α. At the outermost position of the second force receiving member 70, the second force receiving member 70 receives an external force (second external force) from the force application member 60. Therefore, this structure is provided larger in the distance between the urging member 60 and the rotation axis of the developing unit 41 than the structure in which the urging member is moved toward the process cartridge to separate the developing roller from the photosensitive drum. Therefore, adopting this structural arrangement makes it possible to reduce the amount of torque necessary to separate the developing roller 42 from the photosensitive drum 30.

In this embodiment, the elastic portion 71b is an integral part of the first force receiving member 71. However, the elastic portion may be a part of other components as long as it can absorb the force applied to the first force receiving member 71 due to the above-described positional change of the cartridge 50. Or may be a separate component. For example, the force applied to the first force receiving member 71 due to the positional change of the cartridge 50 may be absorbed by: providing an absorbing member independent of the second force receiving member 70 and the first force receiving member 71 between the second force receiving member 70 and the first force receiving member 71; or by forming the second force receiving member of elastic material such that the above forces can be absorbed by deformation of the second force receiving member 71 itself.

Before the image forming operation is started, the urging member 60 is moved in the direction indicated by the arrow mark E to bring the developing roller 42 into contact with the photosensitive drum 30. When the urging member 60 moves in the above-described direction, the second force receiving member 70 stops receiving the force from the rib 60y, as shown in fig. 7. Therefore, the developing roller 42 is brought into contact with the photosensitive drum 30 by the elastic force of the compression spring 95 provided between the developing unit 41 and the drum unit 31, whereby the process cartridge 50 can be prepared for image formation. Before the developing roller 42 comes into contact with the photosensitive drum 30, the photosensitive drum 30 starts to rotate, and the developing roller 42 starts to rotate by the driving force received by the cartridge 50 from the apparatus main assembly 100 through the coupling portion 67. This is because of the following reason. That is, referring to fig. 10(a), the coupling portion 67 is coaxial with the cylindrical portion 46b, so that the coupling portion 67 does not change position even if the developing unit 42 rotates around the cylindrical portion 46 b. That is, in this embodiment, before the developing roller 42 comes into contact with the photosensitive drum 30, the developing roller 42 and the photosensitive drum 30 start to rotate. This arrangement makes it possible to minimize the difference in circumferential speed between the photosensitive drum 30 and the developing roller 42 when the developing roller 42 comes into contact with the photosensitive drum 30. It is therefore possible to minimize the amount of wear generated on the photosensitive drum 30 and the developing roller 42 when they contact each other. After the image forming operation is completed, the developing roller 42 is separated from the photosensitive drum 30 by moving the urging member 60 in the direction indicated by the arrow mark B as described above. After the developing roller 42 is separated from the photosensitive drum 30, the developing roller 42 and the photosensitive drum 30 are stopped (rotated). Thus, this arrangement minimizes the difference in circumferential speed between the developing roller 42 and the photosensitive drum 30 while they are separated. Therefore, the amount of abrasion of the developing roller 42 and the photosensitive drum 30 at the time of separation thereof is minimized. As a result, this arrangement improves the image quality of the imaging apparatus.

Next, an operation for removing the cartridge 50 from the apparatus main assembly 100 is explained.

First, the door 12 will move from its closed position to an open position. When the door 12 moves, the tray supporting member 14 is lifted in a direction separating from the transfer belt 19 as shown in fig. 3 and 4. The cartridges 50 move upward so that the photosensitive drums 30 in the respective cartridges 50 are separated from the transfer belt 19. Further, the pressing member 61 rotates in the direction indicated by the arrow mark J in fig. 5, separating from the drum unit 31 as described above. In this way, the first force receiving member 71 is separated from the projection 180, whereby the force that keeps the second force receiving member 70 projecting from the outer contour of the developing roller 41 is no longer maintained.

For the second force receiving member 70, the inclined surface 70y2 thereof is in contact with the inclined surface 60y2 of the force applying member 60 as shown in fig. 21. Thus, when the cartridge 50 (cartridge tray 13) is pulled out, the second force receiving member 70 is rotationally moved about its rotational axis 70a back to its standby position (inactivated position) by the component of force to which the inclined surface 70y2 is subjected. Incidentally, as in another embodiment of the present invention, a spring may be employed as the means for generating a force to return the second force receiving member to its standby position. That is, the first embodiment, in which the above-described spring is not employed, is an embodiment in which the number of parts is minimized.

As described above, in this embodiment, the structures of the apparatus main assembly 100 and the cartridge 50 are arranged such that: when the door 12 is moved to its closed position after the cartridge 50 is mounted into the apparatus main assembly 100, the second force receiving member 70 for moving the developing unit 41 protrudes from the outer surface of the developing unit 41. Thus, the cartridge 50 in this embodiment is significantly smaller in height than the cartridge (50) according to the prior art. Further, when the cartridge 50 is mounted, the second force receiving member 70 is held in its standby position. Therefore, the space required for the movement of the cartridge 50 in the apparatus main assembly 100 of this embodiment does not need to be as large as in the main assembly of the image forming apparatus according to the related art. That is, the present invention makes it possible to reduce the size of the opening 80 and to place the urging member 60 significantly closer to the path of the cartridge 50 as compared with the related art, thereby making it possible to reduce the size of the apparatus main assembly 100 in the vertical direction. Further, the force receiving device 90, the pressing member 61, and the force applying member 60 are positioned such that they overlap each other in a direction parallel to the drum axis as shown in fig. 20, so that the lengthwise dimension of the cartridge 50 can be reduced.

Further, when the cartridge 50 is operated by a user or it is transported separately, the second force receiving member 70 is kept in its standby position, and thus is not easily damaged.

In this embodiment, the apparatus main assembly 100 is structured such that: with its projection 180 located below the path of the cassette 50. However, as long as the projection 180 is in contact with the first force receiving member 71 at the time of mounting the cartridge 50 into the apparatus main assembly 100, it does not matter at which position the projection 180 is located. Further, the shape of the projection 180 is optional as long as the projection 180 is capable of moving the first force receiving member 71 by contacting with the force receiving portion 71 c. In other words, the force receiving portion 71c may be a fixing protrusion protruding from the cover 46. However, if the force receiving portion 71c is provided to be fixed, the force receiving portion 71c must be adjustable in height to prevent the force receiving portion 71c from contacting the apparatus main assembly 100 when the cartridge 50y is mounted into the apparatus main assembly 100.

(example 2)

Next, another preferred embodiment of the present invention will be described with reference to fig. 12 and 13. In this embodiment, the cartridge 50 is provided with a first lever 471, a second lever 470, and a gear 472. The first lever 471 has a first force receiving portion 471 c. The second lever 470 has a second force receiving portion 470c and is engaged with the gear 472. This arrangement enables the second lever to move a greater distance than the first lever.

The gear 472 is a step gear including a portion (first portion) engaged with the first rod 471 and having n1 teeth, and a portion (second portion) engaged with the second rod 470 and having n2 teeth. Thus, by making the number of teeth n2 of the second part of the gear 472 larger than the number of teeth n1 of the first part of the gear 472 (n2 > n1), the distance the first lever 471 moves can be enlarged. To specifically explain the operation of the force receiving means in this embodiment, referring to fig. 12(a), when the cartridge 50 is inserted into the apparatus main assembly 100, the second lever 470 is held in the cartridge 50. Then, when the cartridge 50 is correctly positioned relative to the apparatus main assembly 100 by the cartridge positioning portion 101a, the first force receiving portion 471c starts receiving an external force (first external force) from the projection 180, thereby moving upward as indicated by an arrow mark F2. When the first force receiving portion 471c is moved upward as indicated by the arrow F2, the gear 472 rotates, and this rotation of the gear 472 causes the second lever 470 to be moved upward. Thus, immediately after the cartridge 50 is correctly positioned by the cartridge positioning portion 101a, the second lever 470 is at its outermost position as shown in fig. 12 (b). When the second lever 470 is at its outermost position, the force receiving portion 470c of the lever 470 receives an external force (second external force) from the rib 60y3 in the same manner as the second force receiving portion 70c of the second force receiving member 70 receives an external force from the rib 60y3 in the first embodiment.

Further, in this structural arrangement, a coil spring 473 is provided to ensure that the second lever 470 always returns to its standby position. The reason for this is as follows: from the viewpoint of device design, it is difficult to ensure that the component of the force received by the inclined surface 60y1 is large enough to return the force receiving portion 470c to its original position (for example, if the amount of force required to pull the cartridge (tray for a cartridge) increases). In other words, the provision of the coil spring 473 is not essential, as is not essential in the first embodiment.

However, this embodiment will be described herein in connection with the case where the coil spring 473 is provided. In this case, unless the elastic force of the coil spring 473 is smaller than the elastic force of the elastic portion 471b, which is an integral part of the lever 471, the force receiving first member 470 is not allowed to move. Therefore, all that is required is to set the relationship between the force F1 generated by the coil spring 473 and the force F2 generated by the elastic member 471b to F1 > F2.

In this embodiment, the cartridge 450 is designed to be installed in the following manner: first, the gear 472 is rotatably supported by the cover 446 fixedly attached to the bearing unit 445, and then, the second lever 470 and the first lever 471 are connected such that the two levers are engaged with the respective portions of the gear 472. The shape of the apparatus main assembly in this embodiment is the same as that in the first embodiment. Therefore, the force receiving portion necessary to bring the developing roller into contact with or separate the developing roller from the photosensitive drum is the rib 470c of the second lever 470. Other aspects of this embodiment are the same as the first embodiment.

As described above, the force receiving device in this embodiment is the same in effectiveness as the force receiving device in the first embodiment. However, in this embodiment, the distance that the second rod moves can be easily changed by changing the gear ratio between the first and second portions of the gear 472.

Also in this embodiment, when the tray is pulled out, the force receiving member 470 contacts the inclined surface 60y 2. Then, when the cartridge tray is further pulled out, the second force receiving member 470 is pushed back into the developing unit by being moved in the direction indicated by the arrow mark F2 by the action of the inclined surface 60y2, and is stored therein. Therefore, the provision of the return spring 473 is not mandatory.

(example 3)

Next, referring to fig. 14 and 15, a third embodiment of the present invention will be described in connection with a case where the first force receiving member is subordinate to the drum unit 531. First, a method for assembling the cartridge in this embodiment will be described. The cartridge in this embodiment is designed such that the first force receiving member 571 belongs to the drum unit 531. The second force receiving member 570 and the connective rod 574 are attached to the cover 546. Then, the cover 536 is combined with the supporting member 545. Finally, the developing unit 541 and the drum unit 531 are connected by the cover 536 to complete the cartridge 550.

To explain the cartridge 550 in this embodiment in more detail with reference to fig. 14 and 15, first, referring to fig. 14, the projection 5180 of the apparatus main assembly is positioned so as to be opposed to the drum unit. Thus, the first force receiving member 571 is placed in the drum unit 531.

The drum unit is provided with a first force receiving member 571, the first force receiving member 571 has a first force receiving portion 571c and is movable. Further, the drum unit is provided with bars 571 and connecting bars 574. When the connecting rod 574 is held in contact with the rod 571, the connecting rod 574 can move rotationally about the rotational axis 574 a. The developing unit is provided with a second force receiving member 570, the second force receiving member 570 having an elongated hole 570b and being rotatably movable about a rotation axis 570 a. Further, the other lengthwise end of the connective rod 574, opposite to the rod 571, is provided with a projection (connective pin) that fits in the elongated hole of the second force receiving member 570.

When the cartridge 550 is correctly positioned relative to the apparatus main assembly 101 by the cartridge positioning portion 101a, the first force receiving portion 571c starts to receive the external force (first external force) from the projection 5180. Accordingly, the force receiving first member 571 starts to move in the direction indicated by the arrow mark I as shown in fig. 14(b), causing the connecting rod 574 to rotationally move in the direction indicated by the arrow mark m (clockwise direction). Thus, the second force receiving member 570 is rotationally moved about the rotational axis 570a in such a direction that the other end portion of the second force receiving member 570, which is opposite to the elongated hole 570b, is moved upward in an arc as indicated by an arrow mark n. Since the curvature of the elongated hole 570b is set such that: when the developing roller 42 is not in contact with the photosensitive drum, the center of curvature of the elongated hole 570b coincides with the rotational axis of the developing unit 541. Therefore, when the developing unit 541 is separated from the drum unit 531, the connecting rod 574 is not subjected to a load. Also in this embodiment, a return spring 573 is provided. However, the return spring 573 may be eliminated by design change.

Also in this embodiment, by appropriately selecting the lever ratio of the connecting bar, the distance that the second force receiving member moves can be made larger than the distance that the first force receiving member moves.

Further, just like the first force receiving member 70 in the first embodiment, in this embodiment, when the tray is pulled out, the second force receiving member 570 contacts the inclined surface 60y 2. Then, when the cartridge tray is further pulled out, the second force receiving member 570 is pushed back to the developing unit 541 by moving in the direction opposite to the direction indicated by the arrow mark n to be stored therein. Therefore, the provision of the return spring 573 is not mandatory.

(Industrial Applicability)

According to the present invention, it is possible to reduce the size of the process cartridge whose electrophotographic photosensitive drum and developing roller can contact or separate from each other. It is also possible to reduce the size of an electrophotographic image forming apparatus using the above-described process cartridge. Further, the electrophotographic image forming apparatus may be structured such that: the force receiving device for separating the developing roller from the electrophotographic photosensitive drum is not easily damaged when the above-described process cartridge is used by a user or is transported separately.

While the invention has been described in connection with the structures disclosed herein, it is not confined to the details set forth and this application is intended to cover such modifications or changes as may come within the purposes of the improvements or the scope of the following claims.

Claims (20)

1. A process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, comprising:

an electrophotographic photosensitive drum;

a developing roller for developing an electrostatic latent image formed on the electrophotographic photosensitive drum;

a drum frame supporting the electrophotographic photosensitive drum;

a developing frame supporting the developing roller, the developing frame being movable relative to the drum frame and being capable of being in a contact position in which the developing roller is in contact with the electrophotographic photosensitive drum; and

a force receiving device including a first force receiving portion for receiving a first external force and a second force receiving portion provided at an upper portion for receiving a second external force, wherein the second force receiving portion is movable relative to the developing frame, wherein the second force receiving portion is moved from a standby position to an operating position for moving the developing frame from a contact position to a separation position by the first force receiving portion receiving the first external force below the second force receiving portion, wherein the operating position is located above a standby position and the second force receiving portion protrudes out of a top surface of the process cartridge in the operating position, wherein a distance in a vertical direction through which the second force receiving portion moves from the stand-by position to the operating position is larger than a distance through which the first force receiving portion moves by the first external force.

2. A process cartridge according to claim 1, wherein said force receiving means includes a first lever with said first force receiving portion, a rotatable gear member engaged with said first lever, and a second lever with said second force receiving portion, and said second lever is movable by being engaged with said gear member.

3. A process cartridge according to claim 1, wherein said force receiving means includes a first lever provided with said first force receiving portion and a second lever provided with said second force receiving portion, said second lever being rotatable about a rotation center in association with movement of said first lever.

4. A process cartridge according to claim 1, wherein said first force receiving portion is provided on said drum frame.

5. A process cartridge according to claim 1, wherein said force receiving means is provided on said developing frame.

6. A process cartridge according to claim 1, wherein when said process cartridge is mounted to the main assembly of the apparatus, said first force receiving portion contacts the main assembly of the apparatus and receives said first external force.

7. A process cartridge according to claim 1, wherein said second force receiving portion receives a second external force from a force applying means movably provided in said main assembly of the apparatus, when said process cartridge is mounted to said main assembly of the apparatus.

8. A process cartridge according to claim 6, wherein said first force receiving portion receives a first external force by contacting the main assembly of the apparatus at a lower side of said process cartridge.

9. A process cartridge according to claim 1, wherein said process cartridge is detachably mountable to the main assembly of the apparatus through an opening provided in the main assembly of the apparatus in a substantially horizontal direction intersecting with an axial direction of said electrophotographic photosensitive drum.

10. A process cartridge according to claim 1, wherein said main assembly of the apparatus includes a drawer member movable between an inside mounting position and a retracted position, in the retracted position, said process cartridge being mountable thereon.

11. A process cartridge according to claim 1, wherein said second force receiving portion allows said process cartridge to enter the main assembly of the apparatus in the standby position, and when said process cartridge is mounted to the main assembly of the apparatus, said second force receiving portion is moved from the standby position to the operating position.

12. A process cartridge according to claim 1, wherein said drum frame and said developing frame are rotatable relative to each other about a rotational axis, and said second force receiving portion is further from said rotational axis in said operating position than in said stand-by position.

13. A process cartridge according to claim 7, wherein said second force receiving portion is larger than said first force receiving portion in a moving distance in a direction toward said force applying means.

14. A process cartridge according to claim 1, wherein said drum frame rotatably supports said photosensitive drum by means of a cover member.

15. A process cartridge according to claim 1, wherein said developing frame rotatably supports said developing roller by means of a bearing.

16. An electrophotographic image forming apparatus for forming an image on a recording material, the electrophotographic image forming apparatus comprising:

(i) a movable force application member;

(ii) a main assembly contact portion;

(iii) a mounting device;

(iv) a process cartridge detachably mountable to said mounting device, said process cartridge comprising:

an electrophotographic photosensitive drum;

a developing roller for developing an electrostatic latent image formed on the electrophotographic photosensitive drum;

a drum frame supporting the electrophotographic photosensitive drum;

a developing frame supporting the developing roller, the developing frame being movable relative to the drum frame and being capable of being in a contact position in which the developing roller is in contact with the electrophotographic photosensitive drum; and

force receiving means including a first force receiving portion for receiving a first external force when the process cartridge is mounted to the main assembly of the electrophotographic image forming apparatus and a second force receiving portion provided at an upper portion for receiving a second external force when the force applying member is moved, wherein the second force receiving portion is movable relative to the developing frame, wherein the second force receiving portion is moved from a stand-by position to an operating position for moving the developing frame from a contact position to a separation position by the first force receiving portion receiving the first external force below the second force receiving portion, wherein the operating position is located above the stand-by position and the second force receiving portion protrudes beyond a top surface of the process cartridge in the operating position, wherein a distance in a vertical direction through which the second force receiving portion is moved from the stand-by position to the operating position is larger than the first force receiving portion The distance moved by the part under the action of the first external force; and

(vi) feeding means for feeding the recording material.

17. An apparatus according to claim 16, wherein said first force receiving portion receives a first external force by contacting a main assembly of said apparatus at a lower side of said process cartridge.

18. An apparatus according to claim 16, wherein said process cartridge is detachably mountable to the main assembly of the apparatus through an opening provided in the main assembly of the apparatus in a substantially horizontal direction intersecting with an axial direction of said electrophotographic photosensitive drum.

19. An apparatus according to claim 16, wherein the main assembly of the apparatus includes a drawer member movable between an inside mounting position and a retracted position in which said process cartridge is mountable thereon.

20. An apparatus according to claim 16, wherein said second force receiving portion allows said process cartridge to enter the main assembly of the apparatus in the standby position, and when said process cartridge is mounted to the main assembly of the apparatus, said second force receiving portion is moved from the standby position to the operating position.