HK1131221B - Developing apparatus, process cartridge and electrophotographic image forming apparatus - Google Patents

Description

Developing device, process cartridge and electrophotographic image forming apparatus

Technical Field

The present invention relates to a developing device, a process cartridge, and an electrophotographic image forming apparatus using the same.

Here, an electrophotographic image forming apparatus is an apparatus that forms an image on a recording material using an electrophotographic type process. Examples of the electrophotographic image forming apparatus include: an electrophotographic copying machine, an electrophotographic printer (e.g., a laser beam printer, an LED printer, etc.), a facsimile apparatus, a word processor, and the like.

The process cartridge is a unit which integrally contains at least a developing device and an electrophotographic photosensitive drum, and is made to be detachably mountable to the main assembly of the electrophotographic image forming apparatus. The developing device is a device that develops an electrostatic latent image formed on an electrophotographic photosensitive drum with a developer.

Background

Heretofore, in an electrophotographic image forming apparatus to which an electrophotographic image forming process is applied, a process device capable of acting on an electrophotographic photosensitive drum and the electrophotographic photosensitive drum are integrated into a cartridge. The process cartridge type in which the cartridge is detachably mountable to the main assembly of the electrophotographic image forming apparatus is applied. According to this type of process cartridge, maintenance operation of the apparatus is performed by a user without relying on a service person, thereby significantly improving operability. Then, this process cartridge type is widely used in electrophotographic image forming apparatuses.

Light corresponding to image information of a laser, an LED, or a lamp is projected onto an electrophotographic photosensitive drum in an electrophotographic image forming apparatus. Thereby, an electrostatic latent image is formed on the photosensitive drum. The electrostatic latent image is developed by a developing device. The developed image formed on the photosensitive drum is transferred onto a recording material. Thereby, an image is formed on the recording material.

Japanese laid-open patent application 2001-255806 (pages 9-11, fig. 7-14) describes an in-line color electrophotographic image forming apparatus in which a plurality of process cartridges are arranged along a column. The process cartridge 40 includes a drum unit 41 having a photosensitive drum 44 and a developing unit 42 having a developing roller 68, and they are rotatably connected to the swing center shaft 43. The photosensitive drum 44 is provided with a cartridge coupling 60 at an axial end thereof. When the process cartridge 40 is mounted to the apparatus main assembly, the cartridge coupling 60 is engaged with a main assembly coupling 61 provided in the apparatus main assembly, and transmits a driving force. The driving force is transmitted from an input gear 64 as a developing driving force transmitting member provided on the swing center 43 of the developing unit 42 to a developing roller 68 through idler gears 65, 66. Here, when the process cartridge 40 is mounted to the apparatus main assembly, the input gear 64 is engaged with a gear 67 provided in the apparatus main assembly and receives a driving force. More specifically, the driving force transmission from the photosensitive drum 44 and the developing roller 68 of the apparatus main assembly is performed independently of each other.

Disclosure of Invention

Recently, further improvement in image quality is demanded. In the conventional example, the input gear is provided at the swing center, the position of which is constant regardless of the swing motion of the developing unit. Therefore, the driving force is transmitted from the input gear to the developing roller through the idler gear, and a space must be provided in the process cartridge for the transmission of the driving force. Therefore, the rotational accuracy of the developing roller is affected by the engagement between the input gear, the idler gear, and the main assembly gear.

The present invention further develops the prior art structure described above.

Therefore, a primary object of the present invention is to provide a developing device, a process cartridge, and an electrophotographic image forming apparatus, in which the process cartridge or the developing device is positioned by moving a movable member in a direction intersecting with a longitudinal direction of the process cartridge or the developing device, and a retracting mechanism for a main assembly driving force transmitting member for transmitting a rotational driving force to a developing roller is simplified.

Another object of the present invention is to provide a developing device, a process cartridge and an electrophotographic image forming apparatus, wherein an engaging portion is provided on a shaft coupling, and by positioning the engaging portion provided on the shaft coupling on a holding portion, it is not necessary to provide a large guide for engaging with the engaging portion and a main assembly driving force transmitting member, and the developing device, the process cartridge and the electrophotographic image forming apparatus are downsized.

It is another object of the present invention to provide a developing device, a process cartridge and an electrophotographic image forming apparatus in which image quality is improved by improving the rotational accuracy of a developing roller.

According to one aspect of the present invention, there is provided a process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, the main assembly of the electrophotographic image forming apparatus including: a first rotatable main assembly drive force transmission member; a second rotatable main assembly drive force transmission member; a main assembly positioning portion for positioning the process cartridge; a movable member movable between a first position for permitting the process cartridge to enter the main assembly of the electrophotographic image forming apparatus in a longitudinal direction thereof and a second position for urging the process cartridge in a direction intersecting the longitudinal direction so as to position the process cartridge in a main assembly positioning portion; and a main assembly locking member, the process cartridge comprising: an electrophotographic photosensitive drum; a developing roller for developing an electrostatic latent image formed on the electrophotographic photosensitive drum with a developer; a drum coupling member provided on one axial end of the electrophotographic photosensitive drum for engaging with the first main assembly driving force transmitting member and transmitting the first rotational driving force to the electrophotographic photosensitive drum when the process cartridge is mounted to the main assembly of the apparatus; a shaft coupling member provided on one axial end of said developing roller for transmitting a second rotational driving force from a second main assembly driving force transmission member and permitting an offset between an axis of the second main assembly driving force transmission member and an axis of said developing roller, wherein said shaft coupling member includes an engaging portion for engaging with the second main assembly driving force transmission member and receiving the second rotational driving force when said process cartridge is mounted to the main assembly of the apparatus; the engaging portion is movable in a direction intersecting with an axial direction of the developing roller; when the process cartridge enters the apparatus main assembly, the engaging portion is positioned on a retaining portion provided in the process cartridge; when the process cartridge is moved by moving the movable member from the first position to the second position, the engaging portion is positioned on the main assembly locking member; the distance between the axis of the engaging portion and the axis of the developing roller is smaller when the process cartridge is positioned in the main assembly positioning portion than when the engaging portion is positioned by the retaining portion.

According to another aspect of the present invention, there is provided an electrophotographic image forming apparatus for forming an image on a recording material, the electrophotographic image forming apparatus including: (a) a first rotatable main assembly drive force transmission member and a second rotatable main assembly drive force transmission member; (b) a main assembly positioning portion for positioning the process cartridge; (c) a movable member movable between a first position for permitting the process cartridge to enter the main assembly of the electrophotographic image forming apparatus in a longitudinal direction thereof and a second position for urging the process cartridge in a direction intersecting the longitudinal direction so as to position the process cartridge to a main assembly positioning portion; (d) the process cartridge to which a main assembly locking member (e) is detachably mountable to the apparatus main assembly includes: an electrophotographic photosensitive drum; a developing roller for developing an electrostatic latent image formed on the electrophotographic photosensitive drum with a developer; a drum coupling member provided on one axial end of said electrophotographic photosensitive drum for engaging with a first main assembly driving force transmitting member and transmitting a first rotational driving force to the electrophotographic photosensitive drum when said process cartridge is mounted to the main assembly of the apparatus; a shaft coupling member provided on one axial end of said developing roller for transmitting a second rotational driving force from a second main assembly driving force transmission member and permitting an offset between an axis of the second main assembly driving force transmission member and an axis of said developing roller, wherein said shaft coupling member includes an engaging portion for engaging with the second main assembly driving force transmission member and receiving the second rotational driving force when said process cartridge is mounted to the main assembly of the apparatus; the engaging portion is movable in a direction intersecting with an axial direction of the developing roller; when the process cartridge enters the apparatus main assembly, the engaging portion is positioned on a retaining portion provided in the process cartridge; when the process cartridge is moved by moving the movable member from the first position to the second position, the engaging portion is positioned on the main assembly locking member; a distance between an axis of the engaging portion and an axis of the developing roller is smaller when the process cartridge is positioned in the main assembly positioning portion than when the engaging portion is positioned by the retaining portion; (f) a feeding device for feeding the recording material.

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

Drawings

Fig. 1 is a general arrangement of a color electrophotographic image forming apparatus according to an embodiment of the present invention.

Fig. 2 is a cross-sectional view of the process cartridge.

Fig. 3a is a view of a mounting operation of the process cartridge to the apparatus main assembly.

Fig. 3b is a view of a mounting operation of the process cartridge to the apparatus main assembly.

Fig. 3c is a view of a mounting operation of the process cartridge to the apparatus main assembly.

Fig. 4 is a view of a support structure for the developing roller.

Fig. 5 is a view of the structure of an oldham (oldham) coupling.

Figure 6a is a cross-sectional view of the oldham coupling

Figure 6b is a cross-sectional view of the oldham coupling

Fig. 7a is a view of a coupling structure in the process cartridge and the apparatus main assembly.

Fig. 7b is a view of the coupling structure in the process cartridge and the apparatus main assembly.

Fig. 8a is a view of the state of the oldham coupling when the process cartridge in the first embodiment is mounted to the image forming apparatus main assembly.

Fig. 8b is a view of the state of the oldham coupling when the process cartridge in the first embodiment is mounted to the image forming apparatus main assembly.

Fig. 9a is a view of the state of the oldham coupling when the process cartridge in the first embodiment is mounted to the image forming apparatus main assembly.

Fig. 9b is a view of the state of the oldham coupling at the time of mounting the process cartridge to the image forming apparatus main assembly in the first embodiment.

Fig. 9c is a view of the state of the oldham coupling at the time of mounting the process cartridge to the image forming apparatus main assembly in the first embodiment.

Fig. 10a is a view of the state of the oldham coupling when the process cartridge in the first embodiment is positioned in the image forming apparatus main assembly.

Fig. 10b is a view of the state of the oldham coupling when the process cartridge in the first embodiment is positioned in the image forming apparatus main assembly.

Fig. 10c is a view of the state of the oldham coupling when the process cartridge in the first embodiment is positioned in the image forming apparatus main assembly.

Fig. 11a is a view of the state of the oldham coupling at the time of mounting the process cartridge to the image forming apparatus main assembly in the second embodiment.

Fig. 11b is a view of the state of the oldham coupling at the time of mounting the process cartridge to the image forming apparatus main assembly in the second embodiment.

Fig. 12a is a view of the state of the oldham coupling at the time of mounting the process cartridge to the image forming apparatus main assembly in the second embodiment.

Fig. 12b is a view of the state of the oldham coupling at the time of mounting the process cartridge to the image forming apparatus main assembly in the second embodiment.

Fig. 13a is a view of the state of the oldham coupling when the process cartridge in the second embodiment is positioned in the image forming apparatus main assembly.

Fig. 13b is a view of the state of the oldham coupling when the process cartridge in the second embodiment is positioned in the image forming apparatus main assembly.

Fig. 14a is a view of the state of the oldham coupling when the process cartridge in the second embodiment is positioned in the image forming apparatus main assembly.

Fig. 14b is a view of the state of the oldham coupling when the process cartridge in the second embodiment is positioned in the image forming apparatus main assembly.

Fig. 15a is a view of the state of the oldham link when an image is formed in the second embodiment.

Fig. 15b is a view of the state of the oldham link when the image is formed in the second embodiment.

Fig. 16 shows an electrophotographic image forming apparatus in a third embodiment.

Fig. 17 is a view in a state where the process cartridge in the third embodiment is mounted to the image forming apparatus main assembly.

Fig. 18a is a view in a state where the process cartridge in the third embodiment is mounted to the image forming apparatus main assembly.

Fig. 18b is a view in a state where the process cartridge in the third embodiment is mounted to the image forming apparatus main assembly.

Fig. 18c is a view in a state where the process cartridge in the third embodiment is mounted to the image forming apparatus main assembly.

Fig. 19 is a view in a state where the process cartridge in the third embodiment is mounted to the image forming apparatus main assembly.

Fig. 20a is a view of the state of the oldham coupling when the developing device in the fourth embodiment is mounted to the image forming apparatus main assembly.

Fig. 20b is a view of the state of the oldham coupling when the developing device in the fourth embodiment is mounted to the image forming apparatus main assembly.

Fig. 21a is a view of the state of the oldham coupling when the developing device in the fourth embodiment is mounted to the image forming apparatus main assembly.

Fig. 21b is a view of the state of the oldham coupling when the developing device in the fourth embodiment is mounted to the image forming apparatus main assembly.

Fig. 22a is a view of the state of the oldham coupling when the developing device in the fourth embodiment is positioned in the image forming apparatus main assembly.

Fig. 22b is a view of the state of the oldham coupling when the developing device in the fourth embodiment is positioned in the image forming apparatus main assembly.

Detailed Description

The first embodiment:

examples of a process cartridge and a color electrophotographic image forming apparatus (image forming apparatus) according to a first embodiment of the present invention will be described.

(Overall arrangement of image Forming apparatus)

Referring to fig. 1, first, the overall arrangement will be described with respect to the image forming apparatus. In addition, fig. 1 is an overall arrangement of the image forming apparatus according to the embodiment.

Referring to fig. 1, an overall arrangement will first be described with respect to an electrophotographic image forming apparatus (image forming apparatus) 100. As shown in fig. 1, four detachably mountable process cartridges 7(7a, 7b, 7c, 7d) are mounted by mounting members (not shown) from the front side to the rear side of the drawing. In fig. 1, the process cartridges 7 are inclined and juxtaposed with respect to the horizontal direction in the apparatus main assembly 100A.

In each process cartridge 7, there are provided: electrophotographic photosensitive drums (photosensitive drums) 1(1a, 1b, 1c, 1d), and charging rollers 2(2a, 2b, 2c, 2d), developing rollers 25(25a, 25b, 25c, 25d), and process means such as cleaning members 6(6a, 6b, 6c, 6d) arranged integrally around the photosensitive drums 1. The charging roller 2 has a function of uniformly charging the surface of the photosensitive drum 1, and the developing roller 25 has a function of developing and visualizing a latent image formed on the photosensitive drum 1 with toner. The cleaning member 6 has a function of removing the developer remaining on the photosensitive drum 1 after the developer image formed on the photosensitive drum 1 is transferred onto the recording material.

Below the process cartridge 7, a scanner unit 3 is provided which selectively exposes the photosensitive drum 1 according to image information, thereby forming a latent image on the photosensitive drum 1.

A mounting paper cassette 17 containing the recording material S in a lower portion of the apparatus main assembly 100A. A recording material feeding means for the apparatus main assembly 100A is provided so as to feed the recording material S upward. In more detail, there are provided feed rollers 18 for separating and feeding the recording materials S in the paper cassette 17 one by one, and a conveying roller pair 19 for conveying the fed recording material S, and a registration roller pair 20 for providing synchronization between the latent image formed on the photosensitive drum 1 and the recording material S. Above the process cartridges 7(7a, 7b, 7c, 7d), there is provided an intermediate transfer unit 5 as an intermediate transfer means for transferring the toner images formed on the photosensitive drums 1(1a, 1b, 1c, 1 d).

The intermediate transfer unit 5 includes: a driving roller 21 and a driven roller 22, a primary transfer roller 23(23a, 23b, 23c, 23d) disposed at a position opposing each photosensitive drum 1, a secondary transfer roller 24, an opposing roller 87 disposed at a position opposing the secondary transfer roller 24, and an intermediate transfer belt 5a extending around those rollers. The intermediate transfer belt 5a is circulated so that all the photosensitive drums 1 are opposed and in contact, and by applying a voltage to the primary transfer roller 23, primary transfer from the photosensitive drums 1 onto the intermediate transfer belt 5a is carried out. By applying a voltage between the opposing roller 87 provided in the intermediate transfer belt 5a and the secondary transfer roller 24, the toner is transferred from the intermediate transfer belt 5a onto the recording material S.

In the case of forming an image, each photosensitive drum 1 rotates, and the photosensitive drum 1 that has been uniformly charged by the charging roller 2 is selectively exposed by the scanner unit 3. Thereby, an electrostatic latent image is formed on the photosensitive drum 1. The electrostatic latent image is developed by the developing roller 25. Thereby, a color developer image is formed on each photosensitive drum 1. In synchronization with this image formation, the registration roller pair 20 feeds the recording material S to the secondary transfer position where the opposed roller 87 and the secondary transfer roller 24 are opposed to each other with the intermediate transfer belt 5a disposed therebetween. Each color developer image on the intermediate transfer belt 5a is secondarily transferred onto the recording material S by applying an image transfer bias to the secondary transfer roller 24. By so doing, a color image is formed on the recording material S. The recording material S having the color image is heated and pressurized by the fixing portion 88, and the developer image is fixed. Subsequently, the recording material S is discharged to the discharge portion 90 by the discharge roller 89. The fixing portion 88 is provided in an upper portion of the apparatus main assembly 100A.

(processing box)

Referring to fig. 2, the process cartridge 7 according to the present embodiment will be described. Fig. 2 shows a main part of the process cartridge 7 containing developer (toner). The process cartridge 7a containing yellow toner, the process cartridge 7b containing magenta toner, the process cartridge 7c containing cyan toner, and the process cartridge 7d containing black toner have the same configuration.

The process cartridge 7 includes: drum units 26(26a to 26d) provided with the photosensitive drums 1, the charging rollers 2, and the cleaning members 6, and developing units 4(4a to 4d) having developing members.

The photosensitive drum 1 is rotatably mounted in a cleaning frame 27 of the drum unit 26 via a bearing (not shown). The charging roller 2 and the cleaning member 6 are disposed around the photosensitive drum 1. The residual toner removed from the surface of the photosensitive drum 1 by the cleaning member 6 falls into the removal toner chamber 27 a. By transmitting the driving force of a driving motor (not shown) as a driving source to the drum unit 26, the photosensitive drum 1 rotates in correspondence to the image forming operation. The charging roller bearing 28 is movable in the direction of arrow D with respect to the cleaning frame 27. The shaft 2j of the charging roller 2 is rotatably mounted to the charging roller bearing 28, and the charging roller bearing 28 is pressed toward the photosensitive drum 1 by the charging roller pressing member 46.

The developing unit 4 as a developing device includes a developing roller 25 and a developing device frame 31, and the developing roller 25 is rotatable in the direction of arrow B and is in contact with the photosensitive drum 1. The developing roller 25 is rotatably supported on the developing device frame 31 by bearing members 32R, 32L mounted on the end portions of the developing device frame 31. Around the developing roller 25, a toner supply roller 34 and a developing blade 35 are provided, the toner supply roller 34 rotating in the direction of arrow C in contact with the developing roller 25, and the developing blade 35 for regulating the toner layer on the developing roller 25. A toner feeder 36 is provided for agitating the toner contained in the toner containing portion 31a of the developing device frame 31 and for feeding the toner to the toner supply roller 34.

The developing unit 4 is rotatably connected to the drum unit 26 with the rotational center thereof aligned with the shafts 37R, 37L, and the shafts 37R, 37L are engaged with the holes 32Rb, 32Lb of the bearing members 32R, 32L. During image formation of the process cartridge 7, the developing unit 4 is urged by the pressure spring 38, which rotates about the shafts 37R, 37L, and the developing roller 25 contacts the photosensitive drum 1.

(mounting mechanism for mounting Process Cartridge to Main Assembly of image Forming apparatus)

Referring to fig. 3, a mechanism for mounting the process cartridge 7 of the present invention to the apparatus main assembly 100A will be described.

Fig. 3a is a view of a state before the process cartridge 7 is mounted to the apparatus main assembly 100A. In fig. 3a, the process cartridge 7 enters in the direction of arrow E through the opening 82b of the front side plate 82 of the apparatus main assembly 100A and is mounted. Here, the direction E is the longitudinal direction of the process cartridge 7. The longitudinal direction of the process cartridge 7 is the axial direction of the photosensitive drum 1, and is also the axial direction of the developing roller 25. At the time of the mounting operation, the guide portion 27b integrally provided on the cleaning frame 27 of the process cartridge 7 is mounted in the direction of the arrow E while being guided in a state of being placed on the guide portion 81a of the guide member 81 provided in the apparatus main assembly 100A. The guide 81 is a mounting member for detachably mounting the process cartridge 7.

Fig. 3b is a view of a state in which the process cartridge 7 is mounted to the rear side plate 83 in the mounting direction. When the process cartridge 7 advances in the direction of the arrow E, the abutment portion 27c integrally provided on the cleaning frame 27 comes into contact with the rear side plate 83 of the apparatus main assembly 100A, by doing so, the process cartridge 7 is inserted to the rear side plate 83. By this, the position of the longitudinal direction of the process cartridge 7 becomes determined, but in this state, the process cartridge 7 is not completely positioned in the apparatus main assembly 100A. More specifically, in the up-down direction (the direction intersecting the longitudinal direction of the process cartridge 7), the process cartridge 7 is not positioned. The photosensitive drum 1 is not in contact with the transfer belt 5a of the intermediate transfer unit 5.

Fig. 3c is a view of a state in which the process cartridge 7 is completely set to the apparatus main assembly 100A. After the process cartridge 7 is mounted to the rear side plate 83 in the longitudinal direction, the movable members 84R, 84L provided in the apparatus main assembly 100A press the portions-to-be-pushed 27Ld, 27Rd integrally provided on the cleaning frame 27 in the direction of the arrow F. The movable members 84R, 84L move in association with a switch cover (not shown) provided in the apparatus main assembly 100A. At the time of mounting the process cartridge 7, an opening-and-closing cover (not shown) opens and closes an opening (not shown) provided in the apparatus main assembly 100A. The positioning portions 27Re, 27Le integrally provided on the cleaning frame 27 are respectively brought into contact with the abutting portion 82a of the front side plate 82 and the abutting portion 83a of the rear side plate 83 of the apparatus main assembly 100A, whereby the process cartridge 7 is positioned with respect to the up-down direction. By this, the process cartridge 7 is completely positioned in the apparatus main assembly 100A. In addition, in this state, the photosensitive drum 1 and the transfer belt 5a also contact each other.

In other words, the rear side plate 83 abutted by the abutting portion 27c is a positioning portion with respect to the longitudinal direction of the process cartridge 7. The abutting portions 82a, 83a abutted by the positioning portions 27Re, 27Le are main assembly positioning portions for positioning the process cartridge 7 in the up-down direction.

When the process cartridge 7 enters the inside of the apparatus main assembly 100A, the movable members 84R, 84L can take the first position (the position of fig. 3a) allowing the entry thereof. More specifically, in the first position, the movable members 84R, 84L occupy the position so as not to protrude from the guide portion 81a, so that entry of the process cartridge 7 cannot be prevented. At this time, the opening and closing cover (not shown) is in a position for opening the opening (not shown). The movable members 84R, 84L can take a second position (the position of fig. 3c) for pressurizing the process cartridge 7 in a direction intersecting the longitudinal direction (the entering direction) of the process cartridge 7, so as to position the process cartridge 7 in the main assembly positioning portion. More specifically, the movable pieces 84R, 84L are in positions protruding from the guide portion 81 a. At this time, the opening and closing cover (not shown) is in a position for closing the opening (not shown). It moves from a position specifically for releasing the switch cover (not shown) to a position for closing, so that the movable members 84R, 84L move from the first position to the second position. More specifically, when the process cartridge 7 shown in fig. 3a is mounted in the longitudinal direction, it may be mounted to space the photosensitive drum 1 from the transfer belt 5a so that the photosensitive drum 1 and the transfer belt 5a do not rub against each other. By the movable members 84R, 84L moving from the first position to the second position, the photosensitive drum 1 can be brought into contact with the transfer belt 5 a.

(supporting structure of developing roller and Oldham coupling in Process Cartridge)

Referring to fig. 4 to 6, the structure of the process cartridge 7 according to the present embodiment, which employs the oldham coupling 48 as the shaft coupling, and the supporting structure of the developing roller 25 will be described. Fig. 4 shows one longitudinal end of the supporting portion of the developing roller 25. In fig. 4, the developing roller shaft 25j of the developing roller 25 is rotatably engaged with the inner surface of the bearing portion 32Lc integrally provided on the bearing member 32L. Between the rubber roller portion 25g of the developing roller 25 and the bearing 32Lc, a regulating roller 47 for regulating the degree of contact of the developing roller 25 with the photosensitive drum 1 is rotatably engaged with the developing roller shaft 25 j. Although the support structure of one longitudinal end of the developing roller 25 has been described so far, the bearing is also integrally provided at the other longitudinal end in the bearing member, and rotatably engaged with the other end of the developing roller shaft.

Referring to fig. 5 and 6, the structure of the oldham coupling 48 as the shaft coupling of this embodiment will be described. Here, the support member 32L is omitted for the purpose of describing the structure of the oldham coupling 48.

In fig. 5, the oldham coupling 48 comprises: a driven-side engaging portion 48a, an intermediate engaging portion 48b, and a driving-side engaging portion 48 c. The driven-side engaging portion 48a is fixed to an end portion of the developing roller shaft 25 j. As a fixing method, they may be coupled by a spring pin or a parallel pin. In fig. 5, a cutout portion 25c is provided in an end surface of the developing roller shaft 25j, it is cut into a configuration corresponding to a hole of the driven-side engaging portion 48a, and they are connected. The driving-side engaging portion 48c is rotatably engaged with the engaging portion supporting member 49. The driving side engaging portion 48c as an engaging portion is provided with projections 48c1-48c4 engaging with the main assembly developing coupling 53 (fig. 7), said main assembly developing coupling 53 being the second main assembly driving force transmitting member of the apparatus main assembly 100A. The oldham coupling 48 transmits a rotational driving force (second rotational driving force) from the apparatus main assembly 100A to the developing roller 25, allowing misalignment between the axis of the main assembly developing coupling 53 and the axis of the developing roller 25.

Referring to fig. 6, the structure of the oldham coupling 48 will be described in more detail. Fig. 6a is a sectional view seen in the direction of arrow H of fig. 5, and fig. 6b is a sectional view seen in the direction of arrow G of fig. 5.

In fig. 6a, the driven side engagement portion 48a is provided with an integral rib 48a 1. The intermediate engaging portion 48b is provided with a groove 48ba1, and the rib 48a1 and the groove 48ba1 are engaged with each other for movement in the direction of arrow G in fig. 5.

In fig. 6b, the rib 48c6 is integrally provided on the drive-side engaging portion 48 c. The intermediate engaging portion 48b is provided with a groove 48bc1, and the rib 48c6 and the groove 48bc1 are engaged with each other for movement in the direction of arrow H in fig. 6.

Fig. 7a shows the structure of the coupling provided in the process cartridge 7. The end surfaces of the driving side engaging portions 48c of the oldham couplings 48 provided in the developing unit 4 are integrally provided with protrusions 48c1-48c3 protruding toward the axial direction. A central projection 48c4 as an engaging portion positioning portion for aligning the main assembly coupling 53 and the axis with each other projects from an end surface of the driving side engaging portion 48c in the axis direction. The free end of the photosensitive drum 1 is provided with a drum coupling 1c having a triangular prism configuration. The guide portion 49b of the engaging portion supporting member 49 is guided to move in the groove 50a of the side cover 50 in the direction intersecting the axial direction of the developing roller 25, the side cover 50 being fixed to the developing unit 4 by a screw or the like, not shown. In other words, the driving-side engaging portion 48c can move in a direction intersecting the axis 25 of the developing roller 25.

Fig. 7b shows the structure of the coupling provided in the apparatus main assembly 100A. In fig. 7b, a drum driving coupling 66 as a first main assembly driving force transmitting member for transmitting a driving force from the apparatus main assembly 100A to the photosensitive drum 1 is provided with a hole 66a having a substantially triangular cross section. After the process cartridge 7 is positioned in the main assembly positioning portions 82a, 83a by the movable members 84R, 84L, the coupling moving mechanism 66b is moved in the arrow m direction. Thereby, the drum driving coupling 66 moves together with the coupling moving mechanism 66b toward the process cartridge 7 in the axial direction of the photosensitive drum 1. When the phases of the holes 66a of the drum coupling 1c and the drum drive coupling 66 are misaligned, the end surface 1c1 of the drum coupling 1c and the end surface 66c of the drum drive coupling 66 contact each other. In this case, the drum driving link 66 is retracted in the arrow n direction against the urging force of the spring 66b1 provided in the moving plate 66b 2. When the phases of the drum coupling 1c and the hole 66a are aligned with each other due to the rotation of the drum drive coupling 66, the drum drive coupling 66 is moved in the direction of the arrow r by the urging force of the spring 66b1, and the coupling 1c and the hole 66a are engaged with each other. The rotational driving force (first rotational driving force) is transmitted to the photosensitive drum 1 through the drum drive coupling 66. The process cartridge 7 shown in fig. 3c is positioned in the main assembly positioning portions 82a, 83a by the movable members 84R, 84L, whereby the drum coupling 1c is engaged with the drum driving coupling 66. Thus, the drum driving coupling 66 is retracted until the process cartridge 7 is positioned in the main assembly positioning portions 82a, 83 a. Therefore, the above-described link moving mechanism 66b is used.

On the other hand, the main assembly developing coupling 53 is urged only toward the process cartridge 7 in a direction parallel to the axis of the developing roller 25 by a pressing member 53c such as a compression spring. The developing roller 25 is provided with an oldham coupling 48. Therefore, as shown in fig. 3b, the main assembly developing coupling 53 and the oldham coupling 48 can be engaged with each other before the process cartridge 7 is positioned in the main assembly positioning portions 82a, 83 a. When the process cartridge 7 enters the apparatus main assembly 100A, the driving side engaging portion 48c may be deviated from the axis of the developing roller 25 as long as it is positioned at an appropriate position to engage with the main assembly developing coupling 53. Therefore, the retracting mechanism in the main assembly developing coupling 53 does not need to be the coupling moving mechanism used for the drum driving coupling 66, and therefore, a simple structure is satisfactory.

The detailed structure of the main assembly developing coupling 53 will be described. The main assembly developing coupling 53 is provided with holes 53b1, 53b2 and 53b 3. The main assembly developing coupling 53 is urged toward the process cartridge 7 in a direction parallel to the axis of the developing roller 25 by a pressing member 53c such as a compression spring.

When the driving side engaging portion 48c and the main assembly developing coupling 53 are engaged with each other when the process cartridge 7 enters the apparatus main assembly 100A, the projections 48c1-48c3 and the holes 53b1-53b3 may be out of phase with each other. In this case, the free ends of the projections 48c1-48c3 are in contact with the portions other than the holes 53b1-53b3, and the main assembly developing coupling 53 is retracted in the axial direction against the urging force of the pressing member 53 c. However, when the phases of the projections 48c1-48c3 and the holes 53b1-53b3 are aligned by rotating the main assembly developing coupling 53, the main assembly developing coupling 53 is advanced by the urging force of the pressing member 53 c. Then, the projections 48c1-48c3 and the holes 53b1-53b3 are engaged with each other, and the central boss 48c4 and the central hole 53b4 as the transmission positioning portion are engaged with each other, so that the axes (rotational axes) of the main assembly developing coupling 53 and the driving side engaging portion 48c are aligned with each other. When the protrusions 48c1-48c3 are in phase alignment with the holes 53b1-53b3, they are engaged with each other, so that the rotational driving force is transmitted to the developing roller 25.

Here, a rotational driving force is supplied to the drum driving coupling 66 and the main assembly developing coupling 53 from a motor (not shown) provided in the apparatus main assembly 100A. It is desirable to have one motor for all the process cartridges or one motor to cover all the process cartridges.

As described earlier, independently of the driving input to the photosensitive drum 1, the driving force is directly input from the apparatus main assembly 100A to the developing roller 25. Therefore, the rotational accuracy of the photosensitive drum 1 is not affected by the rotation of the developing roller 25, and further, the rotational accuracy of the developing roller 25 itself is improved, so that the image quality can be improved.

(operation of Oldham coupling when the process cartridge is mounted to the main assembly of the image forming apparatus)

Referring to fig. 8 to 10, the operation of the oldham coupling 48 when the process cartridge 7 of the present invention is mounted to the image forming apparatus main assembly 100A will be described. Fig. 8a is a view of the process cartridge 7 (fig. 3a) mounted toward the rear side plate 83 as viewed from the downstream side (with respect to the mounting direction). Fig. 8b is a cross-sectional view (arrow V1) as seen from the longitudinal end surface.

As shown in fig. 8b, the axis 53a of the main assembly developing coupling 53 of the apparatus main assembly 100A is offset from the axis 25k of the developing roller 25 of the process cartridge 7. In more detail, when the process cartridge 7 enters the apparatus main assembly 100A, the photosensitive drum 1 and the developing roller 25 can be lowered so that the photosensitive drum 1 and the transfer belt 5a do not rub. The main assembly developing coupling 53 is provided so that the axis 25k and the axis 53a of the developing roller 25 are substantially aligned with each other when the process cartridge 7 is positioned in the main assembly positioning portions 82a, 83 a. The driving side engaging portion 48c is pushed by the pusher 54 via the engaging portion supporting member 49, and the driving side engaging portion 48c is positioned in the holding portion 27f provided in the cleaning frame 27. By this, the axis 48c5 of the driving side engaging portion 48c is disposed at a position substantially aligned with the axis 53a, so that the driving side engaging portion 48c is easily engaged with the main assembly developing coupling 53 when the process cartridge 7 is fixed. More specifically, the driving side engaging portion 48c is positioned in the retaining portion 27f such that the axis 48c5 is located closer to the axis 53a of the main assembly developing coupling 53 than the axis 25k when the process cartridge 7 enters the apparatus main assembly 100A. The distance between the axis 48c5 and the axis 25k of the developing roller 25 is D1 here. Therefore, by positioning the engaging portion 48c in the holding portion 27f, it is not necessary to provide a large guide for engagement in the engaging portion 48c and the main assembly developing coupling 53, and therefore downsizing of the process cartridge 7 and the electrophotographic image forming apparatus 100 can be achieved. The pushing member 54 is used to push the joint supporting member 49. However, by mounting the elastically deformable elastic portion integrally on the engaging portion supporting member 49, the engaging portion supporting member 49 can be brought into contact with the holding portion 27 f.

Fig. 9a is a view of the process cartridge 7 (fig. 3b) mounted to the rear side plate 83 of the apparatus main assembly 100A as viewed from the downstream side (with respect to the mounting direction). Fig. 9b is a cross-sectional view (arrow V2) as seen from the longitudinal end surface.

As shown in fig. 9a, when the process cartridge 7 is mounted to the rear side plate 83, the process cartridge 7 is not yet pressed by the movable member 84 while it is guided on the guide 81 of the apparatus main assembly 100A. For this reason, the process cartridge 7 is not completely positioned in the apparatus main assembly 100A, but the photosensitive drum 1 is spaced apart from the transfer belt 5 a.

As shown in fig. 9b, when the projections 48c1-48c3 and the holes 53b1-53b3 are out of phase alignment relative to each other in this state, the contact portion 49b is contacted and positioned in the main assembly lock 85 provided in the apparatus main assembly 100A, in place of the retaining portion 27 f. When the contact portion 49b is positioned by the main assembly locking portion 85, it is guided by an inclined surface 85a provided at the free end of the main assembly locking portion 85, as shown in fig. 9 b. Therefore, a gap is provided between the contact portion 49b and the holding portion 27 f. Here, the driving-side engaging portion 48c is rotatably engaged with the engaging portion supporting member 49. Thus, the driving side engaging portion 48c is positioned in the main assembly locking member 85 through the engaging portion supporting member 49. Therefore, the distance D2 between the axis 48c5 and the axis 25k of the developing roller 25 is smaller than the above-described distance D1. The main assembly developing coupling 53 is urged by the projections 48c1-48c3 of the driving side engaging portion 48c so as to retreat in the direction of arrow J (axial direction) in the figure.

As shown in fig. 9c, after the process cartridge 7 is inserted to the rear side plate 83 (fig. 3), in a state where the phases of the projections 48c1-48c3 and the holes 53b1-53b3 are aligned with each other, the projection 48c4 and the hole 53b4 are engaged with each other, so that the driving side engaging portion 48c is positioned. In that case, the contact portion 49b of the engaging portion supporting member 49 and the main assembly locking member 85 are spaced apart from each other. Therefore, the distance D3 between the axis 48c5 and the axis 25k of the developing roller 25 is here smaller than the above-described distances D1 and D2.

Fig. 10a is a view of the process cartridge 7 (fig. 3c) which is pressure-positioned in the main assembly positioning portions 82a, 83a by the movable members 84R, 84L as viewed from the downstream side (with respect to the mounting direction). Fig. 10b is a cross-sectional view (arrow V3) as seen from the side along the longitudinal direction with respect to fig. 10 a.

As shown in fig. 10a, the cleaning frame 27 of the process cartridge 7 receives a force from the movable member 84 so that it is pushed in the arrow direction. By this, the cartridge positioning portion 27g1 is brought into contact with the abutment portion 83a of the rear side plate of the apparatus main assembly 100A, so that the process cartridge 7 is completely positioned in the apparatus main assembly 100A, and the photosensitive drum 1 and the transfer belt 5a are brought into contact with each other. The axis 25k of the developing roller 25 is substantially aligned with the axis 53a of the main assembly developing coupling 53. Here, the cartridge positioning portion 27g1 is a part of a drum bearing 27g provided in the cleaning frame 27, the drum bearing 27g rotatably supporting the photosensitive drum 1. The contact portion 49b of the engaging portion supporting member 49 is contacted and prevented by the main assembly lock 85 (fig. 10b), or the projection 48c4 of the driving side engaging portion 48c is engaged with the hole 53b4 of the main assembly developing coupling 53 and the driving side engaging portion 48c is positioned (fig. 10 c). For this reason, even if the process cartridge 7 moves in the arrow I direction, the driving-side engaging portion 48c restricts the movement, and therefore it does not move together with the process cartridge 7. Thus, the main assembly lock 85 is positioned downstream of the main assembly developing coupling 53 in the moving direction (arrow direction) of the process cartridge 7. Therefore, the distance D4 (fig. 10b) and the distance D5 (fig. 10c) between the axis 48c5 and the axis 25k of the developing roller 25 are smaller than the above-described D1, D2, and D3.

As shown in fig. 10b, when the phases of the projections 48c1-48c3 and the holes 53b1-53b3 are out of phase with each other, the projections 48c1-48c3 and the holes 53b1-53b3 are aligned in proper phase by rotating the main assembly developing coupling 53. And the driving side engaging portion 48c and the main assembly developing coupling 53 are engaged with each other. As shown in fig. 10c, on the other hand, if the holes 53b1-53b3 provided in the main assembly developing coupling 53 and the projections 48c1-48c3 of the driving side engaging portion 48c are in phase alignment with each other, the driving side engaging portion 48c and the main assembly developing coupling 53 are engaged with each other. The rotational driving force (second rotational driving force) is transmitted to the driving side engaging portion 48c by the rotation of the main assembly developing coupling 53.

As has been described previously, in the structure for positioning in the main assembly positioning portions 82a, 83a by the movable members 84R, 84L in the direction intersecting the entering direction of the process cartridge 7, the retracting mechanism for the main assembly coupling 53 can be simplified, and therefore the image forming apparatus 100 can be downsized.

By positioning the driving side engaging portion 48c provided in the oldham coupling 48 in the retaining portion 27f, it is not necessary to provide a large guide for engaging in the driving side engaging portion 48c and the main assembly developing coupling 53. Therefore, miniaturization of the process cartridge 7 and the electrophotographic image forming apparatus 100 can be achieved.

Although the example using the oldham coupling 48 has been described in the present embodiment, it is also satisfactory to use another coupling (e.g., a lateral coupling) or the like having an effect of absorbing a rotational change that is generated when the axes (rotational axes) of the input portion and the output portion deviate from each other.

Second embodiment:

in the cartridge according to the second embodiment, the operation of the oldham coupling at the time of mounting to the image forming apparatus main assembly will be described with reference to fig. 11 to 15. In describing the present embodiment, the same reference numerals as those of the previous embodiments are given to elements having corresponding functions in the present embodiment, while detailed description thereof is omitted for the sake of brevity.

Fig. 11a is a view of mounting the process cartridge 7 (fig. 3a) toward the rear side plate 83 as viewed from the downstream side (with respect to the mounting direction), and fig. 11b is a sectional view as viewed from the longitudinal end surface (arrow V4).

As shown in fig. 11a and 11b, in the process in which the process cartridge 7 is guided and mounted to the guide 81 of the apparatus main assembly 100A, it is not pressed by the movable member 84. For this reason, it is not completely positioned in the apparatus main assembly 100A. The developing unit 4 is provided with a spacing holder 86 for holding the developing unit 4 at a spacing position to space the developing roller 25 with respect to the photosensitive drum 1 in a state where only the process cartridge 7 is present. Similarly to the first embodiment, the developing unit 4 is urged by a pressure spring (not shown) in the direction in which the developing roller 25 contacts the photosensitive drum 1, and its center is aligned with the shaft 37. However, the spacer 86 is engaged with the hole 27e provided in the side face of the cleaning frame 27, so that the developing unit 4 is rotated in the direction of the arrow L and its center is aligned with the shaft 37, so that it is held at the spaced position. The position of the spacer 86 is now in the engaged position.

However, the engaging portion supporting member 49 is pushed by the pusher 54 in a direction (the direction of arrow I in the drawing) intersecting the axis 25k of the developing roller 25. Therefore, the contact portion 49b of the engaging portion supporting member 49 contacts the holding portion 27f provided in the cleaning frame 27 of the process cartridge 7, thereby determining the position of the engaging portion supporting member 49. The axis (rotational axis) 48c5 of the driving-side engaging portion 48c and the axis 25k of the developing roller are offset from each other. In view of this, similarly to the first embodiment, the photosensitive drum 1 and the developing roller 25 are lowered so that the photosensitive drum 1 and the transfer belt 5a may not rub against each other when the process cartridge 7 enters the apparatus main assembly 100A. For this reason, similarly to the first embodiment, the main assembly developing coupling 53 is provided so that the axis 25k and the axis 53a of the developing roller 25 are substantially aligned with each other when the process cartridge 7 is positioned relative to the main assembly positioning portions 82a, 83 a.

A holding portion 27f is provided on the cleaning frame 27 on which the photosensitive drum 1 is mounted, and the contact portion 49b is in contact with the holding portion 27f for positioning. For this reason, the engaging portion supporting member 49 is positioned with high positional accuracy with respect to the photosensitive drum 1, and the photosensitive drum 1 is mounted with high positional accuracy with respect to the apparatus main assembly 100A. More specifically, if the process cartridge 7 is further advanced in this state as shown in fig. 11b, the axis 48b5 of the driving side engaging portion 48c is disposed at the axis 53a and substantially coincides in position so as to easily engage the main assembly developing coupling 53 with the driving side engaging portion 48 c. More specifically, the driving side engaging portion 48c is positioned on the retaining portion 27f so that the axis 48c5 is closer to the axis 53a of the main assembly developing coupling 53 than the axis 25k is when the process cartridge 7 enters the apparatus main assembly 100A. Here, the distance between the axis 48c5 and the axis 25k of the developing roller 25 is S1. The engaging portion 48c is positioned in the holding portion 27f, and therefore, it is not necessary to provide a large guide for engaging in the engaging portion 48c and the main assembly developing coupling 53, and downsizing of the process cartridge 7 and the electrophotographic image forming apparatus 100 can be achieved.

Fig. 12a shows a view of the process cartridge 7 (fig. 3b) as seen from the downstream side (with respect to the mounting direction), the process cartridge 7 being mounted until it hits the rear side plate 83. Fig. 12b is a cross-sectional view (arrow V5) as seen from the longitudinal end surface.

In the state shown in fig. 12a and 12b it is not pressurized by the movable member 84. For this reason, the process cartridge 7 is not positioned in the main assembly positioning portions 82a, 83a of the apparatus main assembly 100A, and therefore the photosensitive drum 1 is in a state spaced from the transfer belt 5 a. At this time, the axis 53a of the main assembly developing coupling 53 and the axis 25k of the developing roller 25 deviate from each other.

As shown in fig. 12b, when the phases of the projections 48c1-48c3 and the holes 53b1-53b3 are not aligned with each other in this state, the contact portion 49b is contacted and positioned in the main assembly lock 85 in place of the holding portion 27 f. When the contact portion 49b is positioned by the main assembly locking member 85, it is guided by the inclined surface 85a provided at the free end of the main assembly locking member 85, as shown in fig. 11 b. Therefore, the contact portion 49b is spaced apart from the holding portion 27 f. Here, the driving side engagement portion 48c of the oldham coupling 48 is rotatably engaged with the engagement portion support member 49. Thus, the driving side engaging portion 48c is positioned in the main assembly locking member 85 through the engaging portion supporting member 49. Therefore, the distance S2 between the axis 48c5 and the axis 25k of the developing roller 25 is smaller than the above-described distance S1. The main assembly developing coupling 53 is pushed to the projections 48c1-48c3 of the driving side engaging portion 48c and retreated in the direction of arrow J (axial direction) in the drawing.

In a state in which the process cartridge 7 has been set even to the rear side plate 83 (fig. 3), when the phases of the protrusions 48c1-48c3 and the holes 53b1-53b3 are aligned with each other, the case is the same as that of fig. 9c, and thus a detailed description is omitted here.

As shown in fig. 12b, a main assembly releasing member 87 is provided in the apparatus main assembly 100A, said main assembly releasing member 87 being in contact with the spacing holder 86 when the process cartridge 7 is mounted to the apparatus main assembly 100A in the longitudinal direction. Before the mounted process cartridge 7 is positioned in the main assembly positioning portions 82b, 83a, the main assembly releasing member 87 contacts the spacer 86, so that the engagement between the spacer 86 and the hole 27e is released. The position of the spacer 86 at this time is the release position. When the space holder 86 is released, the developing unit 4 moves to the contact position, so that the developing roller 25 can contact the photosensitive drum 1. However, in a state in which the process cartridge 7 is normally provided in the apparatus main assembly 100A, the spacing mechanism 91 provided in the apparatus main assembly 100A is in contact with the force receiving portion 31b of the developing device frame 31. Therefore, even if the spacer 86 is released after the process cartridge 7 is mounted to the apparatus main assembly 100A, the developing roller 25 is not in contact with the photosensitive drum 1.

Fig. 13a is a view of the process cartridge 7 positioned in the main assembly positioning portions 82a, 83a of the apparatus main assembly 100A by the movable member 84 as viewed from the downstream side (with respect to the mounting direction). Fig. 13b is a cross-sectional view (arrow V6) as seen from the longitudinal end surface.

As shown in fig. 13a, the cleaning frame 27 of the process cartridge 7 receives a force from the movable member 84 and is pushed in the direction of arrow I. By this, the cartridge positioning portion 27g1 is in contact with the abutment portion 83a of the rear side plate of the apparatus main assembly 100A, so that the process cartridge 7 is positioned in the apparatus main assembly 100A, and the photosensitive drum 1 and the transfer belt 5a are in contact with each other. Here, the cartridge positioning portion 27g1 is a part of a drum bearing 27g provided in the cleaning frame 27 for rotatably supporting the photosensitive drum 1. The contact portion 49b of the engaging portion supporting member 49 is contacted and locked by the main assembly locking member 85, or the driving side engaging portion 48c is positioned by the engagement between the projection 48c4 provided in the driving side engaging portion 48c and the hole 53b4 provided in the main assembly developing coupling 53. For this reason, even if the process cartridge 7 is moved in the direction of the arrow I, the driving-side engaging portion 48c is held in the position of fig. 12, and it does not move together with the process cartridge 7. Thus, the main assembly locking member 85 is positioned downstream of the main assembly developing coupling 53 with respect to the moving direction of the process cartridge 7 (the direction of arrow I). Here, S3 is smaller than the above-described distances S1 and S2 in terms of the distance between the axis 48c5 and the axis 25k of the developing roller 25.

The force receiving portion 31b provided in the developing unit 4 continues to receive the force from the spacing mechanism 91 in the direction of the arrow N, and thus the developing unit 4 is held at the spacing position, whereby the developing roller 25 is spaced from the photosensitive drum 1.

Fig. 14a is a view of the cartridge moved to a contact position where the developing roller 25 is in contact with the photosensitive drum 1 by rotating the developing unit 4 by operating the spacing mechanism 91 as viewed from the downstream side (with respect to the mounting direction). Fig. 14b is a cross-sectional view (arrow V7) as seen from the longitudinal end surface.

As shown in fig. 14a, the spacing mechanism 91 moves in the direction of arrow P and is spaced from the force receiving portion 31b of the developing unit 4, and therefore the developing unit 4 rotates in the direction of arrow Q around the shaft 37 in accordance with the force of the pressure spring 3 (fig. 2). As shown in fig. 14b, the developing unit 4 is moved to a contact position where the photosensitive drum 1 and the developing roller 25 contact each other. The axis 25k of the developing roller 25 is also substantially aligned with the axis 53a of the main assembly developing coupling 53. The distance S4 between the axis 48c5 and the axis 25k of the developing roller 25 is here smaller than S1, S2, and S3 described above.

Fig. 15a is a view of the process cartridge 7 when viewed from the downstream side (with respect to the mounting direction) at the time of image formation. Fig. 15b is a sectional view seen from the end face in the longitudinal direction (arrow V8).

Here, when the phases of the projections 48c1-48c3 and the holes 53b1-53b3 are not aligned with each other, the projections 48c1-48c3 are aligned in proper phase with the holes 53b1-53b3 by rotating the main assembly developing coupling 53. Thus, the main assembly developing coupling 53 and the driving side engaging portion 48c are engaged with each other, and the rotational driving force (second rotational driving force) of the apparatus main assembly 100A is transmitted to the developing roller 25. In this state, the projection 48c5 provided integrally on the driving side engaging portion 48c and the hole 53b4 provided in the main assembly developing coupling 53 are engaged with each other, and therefore the axis 53a of the main assembly developing coupling 53 and the axis (rotational axis) 48c5 of the driving side engaging portion 48c are aligned with each other. Similarly, the axis (rotational axis) 25k of the developing roller 25 is substantially aligned with the axis 53 a. The contact portion 49b of the engaging portion supporting member 49 is spaced apart from the main assembly locking portion 85.

As described earlier, in the present embodiment, in addition to the effects of the first embodiment, even if it mounts the process cartridge 7 in a state where the photosensitive drum and the developing roller 25 are spaced from each other, the engaging portion 48c of the shaft coupling 48 and the main assembly developing coupling 53 are smoothly engaged with each other, thus improving the mounting performance.

The third embodiment:

(spacer mechanism when remounting Process Cartridge)

A spacing mechanism for remounting the process cartridge 7 to the apparatus main assembly 100A after once it is dismounted from the apparatus main assembly 100A will be described. In the description of the present embodiment, the same reference numerals as those of the previous embodiments are given to elements having corresponding functions in the present embodiment, and detailed description thereof is omitted for the sake of simplicity.

As shown in fig. 14 and 15, in the process cartridge 7 which has been taken out of the apparatus main assembly 100A, the spacing holder 86 is released from the hole 27e of the cleaning frame 27. Therefore, the developing unit 4 is located at the contact position and the photosensitive drum 1 and the developing roller 25 contact each other. When the process cartridge 7 is detached from the apparatus main assembly 100A, the image forming operation of the electrophotographic image forming apparatus 100 is completed. As shown in fig. 13, in order to move the developing unit 4 to the spacing position, the spacing mechanism 91 is in contact with it at the spacing force receiving portion 31 b. With this state of the spacing mechanism 91, the process cartridge 7 is detached from the apparatus main assembly 100A, and the developing unit 4 is returned to the contact position. However, when the process cartridge 7 is mounted to the apparatus main assembly 100A again, the spacing force receiving portion 31b of the developing unit 4 positioned at the contact position abuts against the side of the spacing mechanism 91, and therefore, the process cartridge 7 cannot be mounted to the apparatus main assembly 100A. To prevent this, when the detached process cartridge 7 is remounted, the developing unit 4 is moved to the spacing position in advance.

Referring to fig. 16 to 19, a structure for this will be described. As shown in fig. 16 and 17, the apparatus main assembly 100A is provided with a mounting opening 87 for mounting the process cartridge 7. The apparatus main assembly 100A is provided with a spacing guide portion 92, and the spacing guide portion 92 can be brought into contact with a projection 31d integrally provided with a spacing force receiving portion 31b, the spacing force receiving portion 31b being provided in the developing unit 4 of the process cartridge 7.

As shown in fig. 18a, before the process cartridge 7 enters the apparatus main assembly 100A, the developing unit 4 is in the contact position, and thus the photosensitive drum 1 and the developing roller 25 are in contact with each other. As shown in fig. 18b, when the process cartridge 7 is mounted to the apparatus main assembly 100A, the guide portion 27b integrally provided on the cleaning frame 27 is first guided to the main assembly guide 81 provided in the apparatus main assembly 100A. The projection 31d provided in the developing device frame 31 contacts the slope portion 92a of the interval guide portion 92. As shown in fig. 18c, when the process cartridge 7 is further advanced, the developing unit 4 rotates about the rear bearing member 15 in the direction of arrow J. Then, the developing unit 4 is moved to the spacing position (arrow K), and the developing roller 25 is spaced from the photosensitive drum 1. As shown in fig. 19, when the process cartridge 7 is positioned in the main assembly of the image forming apparatus 100, the spacing force receiving portion 31b is in contact with the spacing mechanism 91 provided on the mounting direction downstream side of the spacing guide portion 92. In this case, the developing unit 4 is in the spaced position, and the process cartridge 7 can be mounted to the main assembly of the image forming apparatus 100 while the developing roller 25 is kept spaced apart from the photosensitive drum 1. In this case, the force gap 31e of the force receiving portion 31b provided on the mounting direction upstream side of the process cartridge 7 has a configuration not to interfere with the mounting guide portion 84. Thereby, the developing unit 4 can be moved to the contact position without interfering with the space guide 84.

As has been described previously, also in the present embodiment, the effects similar to those of the second embodiment are provided.

In addition to the effects in the first embodiment, even if the process cartridge 7 is mounted in a state where the photosensitive drum 1 and the developing roller 25 are spaced apart from each other, the driving side engaging portion 48c and the main assembly developing coupling 53 are smoothly engaged with each other, and thus the mounting performance is improved.

The fourth embodiment:

in the above embodiment, the process cartridge 7 is mounted to the apparatus main assembly 100A. However, the present invention is also preferably applicable when only the developing device is detachably mountable to the apparatus main assembly 100A.

Referring to fig. 20 to 22, the operation of the oldham coupling at the time of mounting the developing device 4 to the apparatus main assembly 100A will be described as a fourth embodiment. In the description of the present embodiment, the same reference numerals as those of the previous embodiments are given to elements having corresponding functions in the present embodiment, and detailed description thereof is omitted for the sake of simplicity.

Fig. 20A shows a state before the developing device 4 is mounted to the apparatus main assembly 100A in its longitudinal direction. Fig. 20b shows a cross section seen from the side in the longitudinal direction (arrow V9).

In fig. 20a and 20b, the driving-side engaging part 48c is pushed by the pusher 54 through the engaging part supporting member 49. The driving-side engaging portion 48c is positioned in the holding portion 31f provided on the developing device frame 31 by the engaging portion supporting member 49. Therefore, similarly to the case shown in the first embodiment, also before the developing device 4 is positioned, the oldham coupling 48 is in a position engageable with the main assembly developing coupling 53. By this, the developing roller 25 has been lowered, thereby preventing friction between the developing roller 25 and the photosensitive drum 1 when the developing device 4 enters the apparatus main assembly 100A. More specifically, when the developing device 4 enters the apparatus main assembly 100A, the driving side engaging portion 48c is positioned in the retaining portion 31f so that the axis 48c5 is at a position closer to the axis 53a of the main assembly developing coupling 53 than the axis 25 k. By positioning the engaging portion 48c in the retaining portion 31f, there is no need to provide a large guide for engagement in the engaging portion 48c and the main assembly developing coupling 53, and therefore downsizing of the developing device 4 and the electrophotographic image forming apparatus 100 is achieved, and it succeeds. The distance between the axis 48c5 and the axis 25k of the developing roller 25 is here L1.

Fig. 21a is a view showing that the developing device 4 is provided on a rear side plate (not shown) of the apparatus main assembly 100A. Fig. 21b is a cross-sectional view (arrow V10) as seen from the longitudinal end surface.

As shown in fig. 21a, when the developing device 4 is guided to the guide 81 of the apparatus main assembly 100A, it is mounted to a rear side plate (not shown), and in this state, it is not urged by the movable member 84 of the apparatus main assembly 100A. Thus, the developing roller 25 is spaced apart from the photosensitive drum 1.

As shown in fig. 21b, when the phases of the projections 48c1-48c3 and the holes 53b1-53b3 are not aligned with each other, in this state, the contact portion 49b is contacted and positioned on the main assembly lock 85 provided in the apparatus main assembly 100A, in place of the retaining portion 31 f. When the contact portion 49b is positioned by the main assembly locking member 85, it is guided by the inclined surface 85a provided at the free end of the main assembly locking member 85 into the state shown in fig. 21 b. Here, the driving side engagement portion 48c of the oldham coupling is rotatably engaged with the engagement portion support member 49. Thus, the driving side engaging portion 48c is positioned in the main assembly locking member 85 through the engaging portion supporting member 49. Therefore, the distance L2 between the axis 48c5 and the axis 25k of the developing roller 25 is here smaller than the above-described distance L1. The main assembly developing coupling 53 is pushed onto the driving side engaging portion 48c and retreated in the direction of arrow J (axial direction) in the drawing.

When the phases of the projections 48c1-48c3 and the holes 53b1-53b3 are aligned with each other, the projection 48c4 provided in the driving side engaging portion 48c and the hole 53b4 provided in the main assembly developing coupling 53 are engaged with each other, and the driving side engaging portion 48c is positioned. In this case, the contact portion 49b of the engaging portion supporting member 49 and the main assembly locking member 85 are spaced apart from each other.

Fig. 22a is a view showing a state in which the developing device is positioned in the apparatus main assembly 100A by the movable member 84. Fig. 22b shows a view of the state (arrow V11) as seen from the longitudinal end surface.

As shown in fig. 22a, the developing device frame 31 of the developing device 4 receives a force from the movable member 84 and is pushed in the direction of the arrow, and the restricting roller 47 provided at the end of the developing roller 25 comes into contact with the photosensitive drum 1. The developing device 4 is completely positioned in the apparatus main assembly 100A, and the developing roller 25 and the photosensitive drum 1 are in contact with each other. The axis 25k of the developing roller 25 is substantially aligned with the axis 53a of the main assembly developing coupling 53. Here, when the developing device is moved in the arrow direction, the contact portion 49b of the engaging portion supporting member 49 is contacted and locked by the main assembly locking member 85, or the projection 48c4 is engaged with the hole 53b4, the driving side engaging portion 48c is positioned in the main assembly developing coupling 53. For this reason, even if the developing device 4 moves in the direction of the arrow, the driving-side engaging portion 48c is held in the position of fig. 21, and it does not move together with the developing device 4. Thus, the developing device 4 positions the main assembly locking member 85 at the downstream side of the main assembly developing coupling 53 with respect to the moving direction of the movable member 84. Therefore, the distance L3 between the axis 48c5 and the axis 25k of the developing roller 25 is smaller here than the above-described L1 and L2.

Here, when the phases of the projections 48c1-48c3 and the holes 53b1-53b3 do not match, the phases of the projections 48c1-48c3 and the holes 53b1-53b3 of the coupling match with each other relatively by the rotation of the main assembly developing coupling 53 as shown in fig. 22 b. Then, the driving side engaging portion 48c is engaged with the main assembly developing coupling 53. On the other hand, if the projections 48c1-48c3 of the driving side engaging portion 48c are aligned in phase with the holes 53b1-53b3 provided in the main assembly developing coupling 53, the driving side engaging portion 48c and the main assembly developing coupling 53 are engaged with each other. The rotational driving force is transmitted by the rotation of the main assembly developing coupling 53.

As described earlier, in the structure for positioning the developing device 4 in the main assembly positioning portions 82a, 83a by the movable members 84R, 84L in the direction intersecting the entering direction, the retracting mechanism of the main assembly developing coupling 53 can be simplified, and the size of the electrophotographic image forming apparatus 100 can be reduced.

The engaging portion 48c provided in the shaft coupling 48 is positioned in the holding portion 31f, so it is not necessary to provide a large guide for engaging in the engaging portion 48c and the main assembly developing coupling 53, and downsizing of the developing device 4 and the electrophotographic image forming apparatus 100 can be achieved.

In the present embodiment, description is made of an example using an oldham coupling, and it is also satisfactory to use another coupling (e.g., a lateral coupling) or the like having an effect of absorbing a rotational change which is generated when the axes (rotational axes) of the input portion and the output portion deviate from each other.

As has been described, according to the present invention, the retracting mechanism of the main assembly driving force transmitting member for transmitting the driving force to the developing roller can be simplified.

By positioning the engaging portion provided in the shaft coupling to the retaining portion, it is not necessary to provide a large guide for engaging in the engaging portion and the main assembly driving force transmitting member, and miniaturization of the process cartridge and the electrophotographic image forming apparatus can be achieved.

In addition, the rotational accuracy of the developing roller can be improved, and thus the image quality can be improved.

(Industrial Applicability)

According to the present invention, it is possible to provide a developing device, a process cartridge, and an electrophotographic image forming apparatus, in which the process cartridge or the developing device is positioned by moving a movable member in a direction intersecting with a longitudinal direction of the process cartridge or the developing device, and a retracting mechanism of a main assembly driving force transmitting member for transmitting a rotational driving force to a developing roller is simplified.

It is also possible to provide the developing device, the process cartridge, and the electrophotographic image forming apparatus in which the engaging portion is provided in the shaft coupling, and by positioning the engaging portion provided in the shaft coupling to the holding portion, a large guide for engaging to the engaging portion and the main assembly driving force transmitting member is unnecessary, and the developing device, the process cartridge, and the electrophotographic image forming apparatus are reduced in size.

It is also possible to provide a developing device, a process cartridge, and an electrophotographic image forming apparatus in which image quality is improved by improving the rotational accuracy of the developing roller.

While the invention has been described with reference to 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 purpose of the improvements or the scope of the following claims.

Claims (25)

1. A process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, said main assembly of said electrophotographic image forming apparatus comprising: a first rotatable main assembly driving force transmitting member, a second rotatable main assembly driving force transmitting member, a main assembly positioning portion for positioning said process cartridge, a movable member movable between a first position for allowing said process cartridge to enter into the main assembly of the electrophotographic image forming apparatus along a longitudinal direction thereof and a second position for urging said process cartridge in a direction intersecting with said longitudinal direction so as to position said process cartridge to said main assembly positioning portion, and a main assembly locking member, said process cartridge comprising:

an electrophotographic photosensitive drum;

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

a drum coupling member provided on one axial end of the electrophotographic photosensitive drum, the drum coupling member being engaged with the first main assembly driving force transmitting member and transmitting a first rotational driving force to the electrophotographic photosensitive drum when the process cartridge is mounted to the main assembly of the apparatus;

a shaft coupling member, provided on one axial end of the developing roller, for transmitting a second rotational driving force from the second main assembly driving force transmitting member and allowing an offset between an axis of the second main assembly driving force transmitting member and an axis of the developing roller,

wherein said shaft coupling member includes an engaging portion which is engaged with said second main assembly driving force transmitting member and receives said second rotational driving force when said process cartridge is mounted to said apparatus main assembly; the engaging portion is movable in a direction intersecting with an axial direction of the developing roller; when the process cartridge enters the apparatus main assembly, the engaging portion is positioned to a retaining portion provided in the process cartridge; when the process cartridge is moved by the movable member moving from the first position to the second position, the engaging portion is positioned to the main assembly locking member; and a distance between an axis of the engaging portion and an axis of the developing roller is smaller when the process cartridge is positioned to the main assembly positioning portion than when the engaging portion is positioned by the retaining portion.

2. A process cartridge according to claim 1, wherein said engaging portion is positioned to said retaining portion by urging said engaging portion in a direction intersecting with said axis when said process cartridge enters said main assembly of the apparatus.

3. A process cartridge according to claim 1, wherein when said process cartridge is moved by said movable member being moved from said first position to said second position, said engaging portion is urged in a direction intersecting with said axis to position said engaging portion to said main assembly locking member.

4. A process cartridge according to claim 1, wherein when said process cartridge enters said main assembly of the apparatus, said engaging portion is positioned to said retaining portion such that an axis of said engaging portion is closer to an axis of said second main assembly driving force transmitting member than an axis of said developing roller.

5. A process cartridge according to claim 1, wherein when said process cartridge enters said main assembly of the apparatus, said electrophotographic photosensitive drum is spaced from a transfer belt provided in said main assembly of the apparatus, and when said process cartridge is positioned to said main assembly positioning portion, said electrophotographic photosensitive drum is brought into contact with said transfer belt.

6. A process cartridge according to claim 1, wherein said holding portion is provided on a frame of said process cartridge.

7. A process cartridge according to claim 6, further comprising a drum bearing provided in said frame and rotatably supporting said electrophotographic photosensitive drum, said drum bearing being brought into engagement with said main assembly positioning portion so as to position said process cartridge.

8. A cartridge according to claim 2, further comprising a pushing member for pushing said engaging portion in said intersecting direction.

9. A process cartridge according to claim 1, further comprising an engaging portion bearing member for rotatably supporting said engaging portion and movable in a direction intersecting with said axis, said engaging portion being positioned in said holding portion by said engaging portion bearing member.

10. The process cartridge as claimed in claim 1, wherein the shaft coupling member comprises an oldham coupling.

11. A process cartridge according to claim 1, wherein said process cartridge comprises a drum unit, a developing unit and a spacer, the drum unit contains the electrophotographic photosensitive drum, the developing unit is movably connected with the drum unit and is movable between a contact position and a spacing position, the contact position for bringing the developing roller into contact with the electrophotographic photosensitive drum, the spacing position for spacing the developing roller from the electrophotographic photosensitive drum, the space holder is movable between an engaging position for holding the developing unit at the spaced position and a releasing position, the release position is for allowing the developing unit to move from the spaced position to the contact position, wherein the spacing holder is moved from the engaging position by abutting the apparatus main assembly when the process cartridge is mounted to the apparatus main assembly.

12. A process cartridge according to claim 1, wherein said process cartridge comprises a drum unit containing said electrophotographic photosensitive drum, and a developing unit movably connected to said drum unit and movable between a contact position for bringing said developing roller into contact with said electrophotographic photosensitive drum and a spacing position for spacing said developing roller from said electrophotographic photosensitive drum, wherein said developing unit comprises a force receiving portion which abuts against a spacing guide portion provided in said main assembly of the apparatus so as to receive a force for moving said developing unit from said contact position to said spacing position when said process cartridge enters said main assembly of the apparatus.

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

(a) a first rotatable main assembly drive force transmission member and a second rotatable main assembly drive force transmission member;

(b) a main assembly positioning portion for positioning the process cartridge;

(c) a movable member movable between a first position for permitting the process cartridge to enter into the apparatus main assembly of the electrophotographic image forming apparatus along a longitudinal direction thereof and a second position for urging the process cartridge in a direction intersecting the longitudinal direction so as to position the process cartridge to the main assembly positioning portion;

(d) a main assembly locking member;

(e) the process cartridge detachably mountable to the main assembly of the apparatus includes:

an electrophotographic photosensitive drum;

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

a drum coupling member provided on one axial end of said electrophotographic photosensitive drum for engaging with said first main assembly driving force transmitting member and transmitting a first rotational driving force to said electrophotographic photosensitive drum when said process cartridge is mounted to said apparatus main assembly;

a shaft coupling member provided at one axial end of the developing roller for transmitting a second rotational driving force from the second main assembly driving force transmitting member and allowing an offset between an axis of the second main assembly driving force transmitting member and an axis of the developing roller,

wherein said shaft coupling member includes an engaging portion which is engaged with said second main assembly driving force transmitting member and receives said second rotational driving force when said process cartridge is mounted to said apparatus main assembly; the engaging portion is movable in a direction intersecting the axial direction of the developing roller; when the process cartridge enters the apparatus main assembly, the engaging portion is positioned to a retaining portion provided in the process cartridge; when the process cartridge is moved by the movable member moving from the first position to the second position, the engaging portion is positioned to the main assembly locking member; a distance between an axis of the engaging portion and an axis of the developing roller is smaller when the process cartridge is positioned to the main assembly positioning portion than when the engaging portion is positioned by the retaining portion; and

(f) a feeding device for feeding the recording material.

14. An apparatus according to claim 13, wherein said second main assembly driving force transmitting member includes a hole for engaging with said projection provided in said engaging portion to transmit the driving force when engaged with said engaging portion, wherein said second main assembly driving force transmitting member is urged toward said process cartridge by a urging member provided in said apparatus main assembly.

15. An apparatus according to claim 13, wherein said main assembly locking member is disposed downstream of said second main assembly driving force transmitting member with respect to a moving direction in which said process cartridge is moved by said movable member moving from said first position to said second position.

16. A developing device detachably mountable to a main assembly of an electrophotographic image forming apparatus, said main assembly of the electrophotographic image forming apparatus comprising: a rotatable main assembly drive force transmission member; a movable member movable between a first position for allowing the developing device to enter the main assembly of the apparatus along a longitudinal direction thereof and a second position for urging the developing device in a direction intersecting the longitudinal direction so as to position the developing device in the main assembly of the apparatus; and a main assembly lock, the developing device including:

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

a shaft coupling member provided on one axial end of the developing roller for transmitting a rotational driving force from the main assembly driving force transmitting member and allowing an offset between an axis of the main assembly driving force transmitting member and an axis of the developing roller,

wherein the shaft coupling member includes an engaging portion which is engaged with the main assembly driving force transmitting member and receives the rotational driving force when the developing device is mounted to the main assembly of the apparatus; the engaging portion is movable in a direction intersecting with an axial direction of the developing roller; when the developing device enters the apparatus main assembly, the engaging portion is positioned to a retaining portion provided in the developing device; the engaging portion is positioned to the main assembly locking member when the developing device is moved by the movable member moving from the first position to the second position; the distance between the axis of the engaging portion and the axis of the developing roller is smaller when the developing device is positioned to the main assembly positioning portion than when the engaging portion is positioned by the retaining portion.

17. An apparatus according to claim 16, wherein said engaging portion is positioned to said holding portion by pushing said engaging portion in a direction intersecting with said axis when said developing device enters said main assembly of the apparatus.

18. An apparatus according to claim 16, wherein when said developing device is moved by said movable member moving from said first position to said second position, said engaging portion is positioned in said main assembly locking member by being urged in a direction intersecting said axis.

19. An apparatus according to claim 16, wherein when said developing device enters said main assembly of the apparatus, said engaging portion is positioned to said holding portion such that an axis of said engaging portion is closer to an axis of said second main assembly driving force transmitting member than an axis of said developing roller.

20. An apparatus according to claim 16, wherein said developing roller is spaced from said electrophotographic photosensitive drum when said developing device enters the main assembly of the apparatus, and said developing roller is brought into contact with said electrophotographic photosensitive drum when said developing device is positioned to said main assembly positioning portion.

21. The apparatus according to claim 16, wherein the holding portion is provided in a frame of the developing device.

22. The apparatus according to claim 17, wherein said developing device includes a pushing member for pushing said engaging portion in said intersecting direction.

23. The apparatus of claim 16, further comprising an engaging portion bearing member that rotatably supports the engaging portion and is movable in a direction intersecting the axis.

24. The device of claim 16, wherein the shaft coupling comprises an oldham coupling.

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

(a) a developing device;

(b) a rotatable main assembly drive force transmission member;

(c) a movable member movable between a first position for allowing the developing device to enter into the apparatus main assembly of the electrophotographic image forming apparatus along a longitudinal direction thereof and a second position for urging the developing device in a direction intersecting the longitudinal direction so as to position the developing device in the apparatus main assembly of the electrophotographic image forming apparatus;

(d) a main assembly locking member;

the developing device is detachably mountable to the apparatus main assembly and includes:

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

a shaft coupling member provided on one axial end of the developing roller for transmitting a rotational driving force from the main assembly driving force transmitting member and allowing an offset between an axis of the main assembly driving force transmitting member and an axis of the developing roller;

wherein the shaft coupling member includes an engaging portion which is engaged with the main assembly driving force transmitting member and receives the rotational driving force when the developing device is mounted to the main assembly of the apparatus; the engaging portion is movable in a direction intersecting with an axial direction of the developing roller; when the developing device enters the apparatus main assembly, the engaging portion is positioned to a retaining portion provided in the developing device; the engaging portion is positioned to the main assembly locking member when the developing device is moved by the movable member moving from the first position to the second position; a distance between an axis of the engaging portion and an axis of the developing roller is smaller when the developing device is positioned to the main assembly positioning portion than when the engaging portion is positioned by the retaining portion; and

(e) a feeding device for feeding the recording material.