EP0905585B1

EP0905585B1 - A process cartridge having a shutter to cover the surface of a photoconductor and image forming apparatus using the same cartridge

Info

Publication number: EP0905585B1
Application number: EP98116499A
Authority: EP
Inventors: Yohtaro c/o Ricoh Company Ltd. Kakitani; Kentaro c/o Ricoh Company Ltd. Matsumoto; Hiroyuki c/o Ricoh Company Ltd. Nagashima; Kiyonori c/o Ricoh Company Ltd. Tsuda; Yonsoku c/o Ricoh Company Ltd. Ri
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Priority date: 1997-09-08
Filing date: 1998-09-01
Publication date: 2007-06-06
Anticipated expiration: 2018-09-01
Also published as: DE69837871T2; CN1210997A; EP0905585A3; JP3484326B2; KR19990029638A; ES2287966T3; JPH1184868A; HK1019488A1; CN1109940C; EP0905585A2; DE69837871D1; KR100310130B1

Description

This invention relates to a process cartridge for an image forming apparatus and an image forming apparatus using the same process cartridge, and more particularly to a process cartridge including covering means such as a shutter to cover a lower part of the circumferential surface of a photoconductor of the image forming apparatus and an area beneath a boundary between the process cartridge and the photoconductor and an image forming apparatus using the same process cartridge.
In image forming apparatus utilizing electrophotography, there is known an apparatus which include a so-called process cartridge in which image forming elements such as a developing device for developing with toner a latent image formed on a photoconductor and a cleaner for salvaging the toner remaining on a surface of the photoconductor are packaged. The apparatus is configured such that the process cartridge is freely inserted into a body of the apparatus for attachment thereto and removed therefrom for maintenance. Some process cartridge is provided with a shutter which covers a lower part of the circumferential surface of the photoconductor to protect it from being damaged when the photoconductor is made apart from surrounding elements for clearing a jammed paper. Another shutter covers an area beneath a boundary between the process cartridge and the photoconductor in addition to the lower part of the circumferential surface of the photoconductor for receiving toner falling from the developing device and/or the cleaner when the process cartridge is removed from the apparatus.
Such a shutter is generally configured to be rotated around a rotating axis which is parallel to an axis of the photoconductor, and when the shutter is moved to and from a position covering the lower part of the circumferential surface of the photoconductor and the area beneath the boundary between the process cartridge and the photoconductor, the shutter is greatly inclined along the circumferential surface of the photoconductor, causing a problem that the toner received by the shutter falls from the shutter and thereby spoils the surroundings.
JP 59-058446 discloses a picture formation device. A cover is provided for protecting an image carrier from detoriating due to exposure to light. The cover is connected with a lever which in turn is linked with a lower housing of the picture formation device. The upper housing may be turned upward around a supporting shaft. The upper housing contains a process cartridge including the photosensitive drum.
JP 59-127073 pertains to an image forming device which prevents a photosensitive drum from detoriation by straylight and the entrance of dust from the outside by closing an opening part when a process cartridge including the photosensitive drum is detached from a device body. The protection is achieved by a cover which is moved by means of a lever when the cartridge is elevated from a holding frame.
The object of the present invention is to provide a process cartridge or an image forming apparatus which allows removal of a process cartridge not including the photosensitive drum without spoiling the surroundings with toner.
The afore-mentioned object is solved by the subject matter of claim 1. The dependent claims are directed to embodiments of advantage.
Advantageously a process cartridge for an image forming apparatus is provided, which includes a cartridge main body having at least one of a developing device for developing with toner a latent image an a photoconductor and a cleaner for salvaging the toner remaining an a surface of the photoconductor and detachably mounted to a main body of the image forming apparatus, and a covering means such as a shutter which covers a covering area including an area beneath a lower part of the circumferential surface of the photoconductor and an area beneath a lower part of at least one of a boundary between the photoconductor and the developing device and a boundary between the photoconductor and the cleaner. The process cartridge is configured such that the shutter moves in a substantially horizontal posture (with respect to the cartridge as shown in fig. 2) between the covering area and a siding area beneath the developing device or the cleaner. Therefore, toner received by the shutter is prevented from falling from the shutter-when the shutter moves.
The cartridge main body may include a means such as a guide for guiding the shutter to move in the substantially horizontal posture (with respect to the cartridge as shown in fig. 2) between the covering area and the siding area. Therefore, the shutter is prevented from being inclined when moved, and thereby falling of the toner from the shutter is more effectively prevented.
Further, an upper surface of the shutter may be bent in a direction orthogonal to a longitudinal direction of the shutter so as to form a concave at a widthwise center part of the upper surface of the shutter. The toner received by the shutter is put to the widthwise center of the shutter due to this concave, and thereby the toner is more effectively prevented from falling from the shutter.
The process cartridge may further include a shutter open/close device which moves the shutter between the covering area and the siding area in cooperation with an open/close member mounted to the main body of the image forming apparatus. Therefore, the shutter may be moved between the covering area and the siding area by the movement of the open/close member of the image forming apparatus.
A more complete appreciation of the present invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

Figure 1 is a schematic drawing illustrating outer appearance of a copying machine as an example of an image forming apparatus according to the present invention;
Figure 2 is a vertical section of a process cartridge according to the present invention when the process cartridge is inserted and attached to a support frame of the image forming apparatus, which already supports the photosensitive drum;
Figure 3 is a plane view of the process cartridge and the photosensitive drum supported in the support frame shown in Figure 2;
Figure 4 is a right side view of the process cartridge shown in Figure 2;
Figure 5 is a plane view of the process cartridge;
Figure 6 is a plane view of the support frame with the photosensitive drum; and
Figure 7 is a schematic drawing illustrating states in which the process cartridge is dislocated upward and downward.

Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, embodiments of the present invention are now described.
Figure 1 is a schematic drawing illustrating outer appearance of a copying machine as an example of an image forming apparatus according to the present invention. A main body 2 of an image forming apparatus 1 includes an upper main body 4 and a lower main body 3. The upper main body 4 is connected to the lower main body 3 at a side of the lower main body 3 by a hinge 4a so as to be freely rotatable in up and down directions to form and close an opening between the upper main body 4 and the lower main body 3 at the other side opposite the hinged side of the upper main body 4. The upper main body 4 includes a scanner (not shown) inside, and a platen plate 5 for pressing an original document which is placed on a contact glass of the scanner is attached on an upper surface of the upper main body 4 so as to be freely opened and closed. The upper main body 4 is supported at its bottom part at the other side of lower main body 4 opposite the hinged side by a rod 6 which freely expands and contracts and is attached to the lower main body 3. The upper main body 4 is provided with a support frame 7 by which a process cartridge 8 is supported so as to be freely detached therefrom.
Next, constitution of the support frame 7 and the process cartridge 8 is described referring to Figures 2 through 6. Figure 2 is a vertical section and Figure 3 is a plane view of the process cartridge 8 when the process cartridge 8 is inserted and attached to the support frame 7. Figure 4 is a right side view and Figure 5 is a plane view of the process cartridge 8. Figure 6 is a plane view of the support frame 7.
The support frame 7 includes a front side plate 9 and a rear side plate 10, which are connected to each other by two guide rails 11 and 12. A support axis 15 is provided in a standing manner to the rear side plate 10 to support a rear side end of a photoconductor 14 with a gear 13 such that the photoconductor 14 is freely rotatable and movable in an axial direction. A circle hole 17 is formed in the front side plate 9 for loosely fitting thereto a cylindrical axis 16 formed on a front side end of the photoconductor 14. A spring 18 is placed between the front side end of the photoconductor 14 and the front side plate 9 around a cylindrical axis 16. The photoconductor 14 can be detached from the support frame 7 by first being moved toward the front side plate 9 while resisting a pressing force of the spring 18 such that the rear side end thereof is detached from the support axis 15, and then being moved toward the rear side plate 10 while being inclined. Further, a first positioning part 19, which is to be engaged in a detachable and rotatable manner with a first engaging part protruding from a rear end of a developing roller (to be described later), and positioning pins 20 and 21, which are to be engaged with an end surface of the process cartridge 8, are provided to the rear side plate 10. Because the support axis 15, which determines an axial center of the photoconductor 14, and the first positioning part 19 are disposed on the same rear side plate 10, their relative position is accurately set. A cone-shaped hole as a second positioning part 22 is formed at a center on the front side surface of the photoconductor 14. A two-step gear 23 to transmit to a salvaging roller of a cleaner (described later) a rotation of a gear 13 which rotates integrally with the photoconductor 14 is rotatably supported by the positioning pin 21. A charger (not shown) is supported by the front side plate 9 and the rear side plate 10.
The process cartridge 8 includes a cartridge body 24 in which a developing device 25 and a cleaner 26 are assembled. The cartridge body 24 includes a cartridge body front plate 27 to which front side ends of the developing device 25 and the cleaner 26 are fixed and a cartridge body rear plate 28 to which rear side ends of the developing device 25 and the cleaner 26 are fixed. The process cartridge 8 further includes guide ribs 29 and 30 at both sides of the cartridge 8. In this embodiment, the guide rib 29 is integrally formed with a toner salvaging case 31 of the cleaner 26 and the guide rib 30 is integrally formed with a toner case 32 of the developing device 25. However, the guide ribs 29 and 30 may be integrally formed with the cartridge body front plate 27 and the cartridge body rear plate 28, respectively, or may be formed as separate members, respectively.
The developing device 25 includes, as shown in Figure 2, a toner case 32 for containing therein toner of a two-component developer and a carrier container 33 for containing carrier of the two-component developer, a stirring device 34 for stirring the toner in the toner case 32, a developing roller 35, and a toner blade 35a to restrict the thickness of the toner on the developing roller 35. To an end of the developing roller 35 at the side of the cartridge body rear plate 28 is fixed a first cylindrical engaging part 36 which is engaged with the first positioning part 19 in a freely rotatable and detachable manner. A gear 37 is fixedly engaged with the first engaging part 36 and is engaged with a transmitting gear (not shown) provided on the upper main body 4 so as to be driven. The transmitting gear provided on the upper main body 4 and the gear 13 of the photoconductor 14 are so configured to be engaged with a driving gear (not shown) which is driven by a motor (not shown). In addition, a cylindrical second engaging part 38, which is engaged with the second positioning part 22 (Figure 6) at the end surface of the photoconductor 14 in a freely detachable and rotatable manner, is provided in a standing manner to the cartridge body front plate 27.
The cleaner 26 includes a salvaging roller 39 provided to the toner salvaging case 31, a movable plate 41 provided to an upper part of the toner salvaging case 31 and supported by the case 31 rotatably around a support axis 40, a cleaning blade 42 supported by the movable plate 41, and a thin plate 43 to receive toner scraped off the photoconductor 14 by the cleaning blade 42. The movable plate 41 is pressed in a clock-wise direction centering around a support axis 40 in Figure 2 so as to separate the cleaning blade 42 from the photoconductor 14. Further, a pressing member 44 to press the movable plate 41 so as to be rotated in a counter-clock-wise direction is provided to the upper main body 4 for elastically bringing the cleaning blade 42 in contact with the photoconductor 14 when the process cartridge 8 is inserted into the support frame 7. An end part of the toner salvaging roller 39 at the side of the cartridge body rear plate 28 protrudes from the toner salvaging case 31 and a gear 39a is fixedly engaged with the end part of the protruded toner salvaging roller 39 (Figures 3 and 5). The thin plate 43 in this embodiment is made of a plastic film capable of being elastically bent.
At both sides of the process cartridge 8, the ribs 29 and 30 are arranged as described above, and guide rails 11 and 12 on which the ribs 29 and 30 are slidably mounted are provided to the support frame 7 of the upper main body 4. In Figure 4, only the guide rail 12 and the guide rib 30 at the side of the developing device 25 are illustrated. The guide rails 11 and 12 are formed with a first inclined surface 45, which is upwardly inclined toward the rear side of the main body 2, on an upper surface of the guide rails 11 and 12 in the vicinity of an end part of the guide rails 11 and 12 in an insertion direction of the process cartridge 8. The guide ribs 29 and 30 are formed with a protruding part 47 having a second inclined part 46, which is upwardly inclined toward the rear side of the main body 2, on a lower surface of the guide ribs 29 and 30 in the vicinity of an end part of the front side of the guide ribs 29 and 30. In this embodiment, a cartridge dislocating device 48 to dislocate the process cartridge 8 in up and down directions is constituted by the guide rails 11 and 12 formed with the first inclined surface 45 and the guide ribs 29 and 30 formed with the protruding part 47 having the second inclined surface 46.
In initial and middle stages of inserting the process cartridge 8 into the support frame 7, the guide ribs 29 and 30 are supported by a flat surface of the middle part of the guide rails 11 and 12 except for the protruding part 47 and thereby the process cartridge 8 is inserted into the support frame 7 in a low position relative to the photoconductor 14. Due to this low position, the developing roller 35 of the developing device 25 and the thin plate 43 of the cleaner 25 does not interfere with the photoconductor 14. Further, in the process of inserting the process cartridge 8 into the support frame 7, the thin plate 41 of the cleaner 26 is rotated in a clock-wise direction (Figure 2) due to the pressing force of the spring, and therefore the cleaning blade 42 does not interfere with the photoconductor 14 either. Accordingly, the photoconductor 14 will never be damaged in the process of inserting the process cartridge 8 into the support frame 7.
In a last stage of inserting the process cartridge 8 into the support frame 7, a leading end of the guide ribs 29 and 30 in the inserting direction of the process cartridge 8 is guided by the first inclined part 45 and thereby dislocated upward, and the protruding part 47 at the end of the front side of the guide ribs 29 and 30 is placed on an upper surface of the guide rails 11 and 12 and thereby the process cartridge 8 is dislocated upward together with the developing device 25 and the cleaner 26. At this time, the positioning pins 20 and 21 are engaged with holes (not shown) formed in the cartridge body rear plate 28, the first engaging part 36 is engaged with the first positioning part 19 and the second engaging part 38 is engaged with second positioning part 22 of the photoconductor 14, and thereby the position of the developing roller 35 relative to the photoconductor 14 is precisely set. In a state that the process cartridge 8 is inserted into the support frame 7, the movable plate 41 of the cleaner 26 is pressed by the pressing part 44 to be rotated, and thereby the cleaning blade 42 elastically contacts the photoconductor 14.
In addition, as illustrated in Figure 2, the process cartridge 8 is provided with a shutter 49 which covers a covering area that includes an area beneath a lower part of the circumferential surface of the photoconductor 14 and areas beneath a lower part of a boundary between the photoconductor 14 and the cleaner 26 and a lower part of a boundary between the photoconductor 14 and the developing device 25. The shutter 49 is bent in a direction orthogonal to a longitudinal direction of the shutter 49 so as to form a concave at the widthwise center part of the upper surface of the shutter 49.
Further, the cartridge body 24 of the cartridge 8 is provided with a guide device 50 to guide the shutter 49 to move while maintaining a substantially horizontal posture (with respect to the cartridge as shown in fig. 2) between the covering area and a siding area below the developing device 25. The guide device 50 could also be structured to move the shutter 49 to a side area below the cleaner 26.
An arc-shaped groove 51 is formed in the cartridge body front plate 27 and the cartridge body rear plate 28, and a pin 52 is formed at both ends of the shutter 49 in the axial direction of the photoconductor 14 being inserted in the groove 51 and put to the side of the cleaner 26. A wire 53 is passed at both ends of the shutter 49 in the axial direction of the photoconductor 14. A bent 54 is formed at both ends of the wire 53 extending along the cartridge body front plate 27 and the cartridge body rear plate 28, respectively. A tip end of the bent 54 at the side of the cartridge body rear plate 28 is rotatably supported by the cartridge body rear plate 28 or a part of the developing device 25 and a tip end of the bent 54 at the side of the cartridge body front plate 27 is rotatably supported by the cartridge body front plate 27 or a part of the developing device 25. Therefore, the shutter 49 can be moved while maintaining a substantially horizontal posture by swinging the wire 53 with the upper end of the bent 54 being as a fulcrum of swinging.
Furthermore, a shutter open/close device 55 for moving the shutter 49 is provided to the inner surface of the cartridge body front plate 27. More specifically, a swing lever 56 for swinging the bent 54 at the front side is rotatably supported by the inner surface of the cartridge body front plate 27 with being pressed in a clock-wise direction by a spring (not shown). Also, an intermediate lever 57 contacting the swing lever 56 is rotatably supported via a support axis 58 by the inner surface of the cartridge body front plate 27. A stopper 59 to support the intermediate lever 57 is formed on the cartridge body front plate 27.
In a state illustrated in Figure 2, the shutter 49 covers the covering area. If the intermediate lever 57 is rotated in this state in a clock-wise direction (upward in the drawing) centering around the support axis 58, the swing lever 56 is rotated in a counter-clock-wise direction pulling the bent 54 of the wire 53 toward the developing device 25 and thereby the shutter 49 is moved from a position below the photoconductor 14 to the siding area below the developing device 25.
The constitution to move the intermediate lever 57 upward in a clock-wise direction is described next. The upper main body 4 is connected to the lower main body 3 in a manner freely rotatable upward and downward as described earlier. Therefore, the support frame 7 and the process cartridge 8 supported by the upper main body 4 are dislocated upward and downward together with the upper main body 4. Figure 7 is a schematic drawing illustrating states in which the process cartridge 8 is dislocated upward and downward. A numeral 60 denotes a rotation fulcrum of the upper main body 4. A open/close member 61 to move the intermediate lever 57 upward in a clock-wise direction when the upper main body 4 is moved downward is mounted to the lower main body 3 rotatably via a fulcrum 62. The open/close member 61 is pressed to a counter-clock-wise direction by a spring (not shown). A stopping position for the open/close member 61 is set by a stopper (not shown).
Accordingly, when the upper main body 4 is moved upward to open the main body 2 for clearing a jammed sheet or for maintenance, or when the process cartridge 8 is removed from the support frame 7, the intermediate lever 57 is released from the open/close member 61 and does not apply to the swing lever 56, which pulls the bent of the wire 53, an external force to press the swing lever 56 to be moved in a direction to move the shutter 49 from the covering area to the siding area, and as a result the shutter 49 is positioned in the covering area between developing device 25 and the cleaner 26. Thus, when the upper main body 4 is opened, even if toner falls from the developing device 25 and/or the cleaner 26, the toner is received by the shutter 49, and the lower circumferential surface of the photoconductor 14 is protected by the shutter 49. Further, even if toner falls from the developing device and/or the cleaner when the process cartridge 8 is removed from the support frame 7, the toner is received by the shutter 49.
When the upper main body 4 is moved downward for closing the main body 2, the process cartridge 8 is lowered and thereby the intermediate lever 57 is pressed by the open/close member 61 to be rotated in a clock-wise direction, and thereby the swing lever 56 is rotated in a counter-clock-wise direction opposite the direction in which the lever 56 is pressed. At this time, the wire 53 is pulled toward the developing device 25 by the action of the swing lever 56 and thereby the shutter 49 is moved to the siding area below the photoconductor 14 from the covering area with the pin 52 being guided by the groove 51 while maintaining a substantially horizontal posture (with respect to the cartridge as shown in fig. 2).
Namely, when the main body 2 is closed and the process cartridge 8 is set to a condition for forming an image, the shutter 49 is released from the covering area so as not to hinder an image forming operation. When the shutter 49 is completely released from the covering area to the siding area, the open/close member 61 is moved back in a clock-wise direction (downward in the drawing) resisting the pressing force of the spring due to a reaction force from the intermediate lever 57. Therefore, the open/close member 61 and the intermediate lever 57 will not unnecessarily receive an extra external force from each other. Thus, in this embodiment, when the shutter 49 is moved between the covering area and the siding area, the toner received by the shutter 49 is prevented from falling from the shutter 49 because the shutter 49 is maintained in a substantially horizontal posture. In particular, the shutter 49 is prevented from being inclined when moved between the covering area and the siding area by the provision of the guide device 50 for guiding the shutter 49 to move between the covering area and the siding area while maintaining a substantially horizontal posture. In addition, because the upper surface of the shutter 49 is bent in a direction orthogonal to a longitudinal direction of the shutter 49 so as to form a concave at the widthwise center part of the shutter 49, the toner received by the shutter is put to the widthwise center of the shutter 49 and thereby falling of the toner from the shutter 49 is more effectively prevented.
Although in the above-described embodiment the process cartridge 8 includes the developing device 25 and the cleaner 26, the present invention may be applied to a process cartridge having either the developing device 25 or the cleaner 27.
Obviously, numerous additional modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described herein.
This application is based on Japanese patent application No. 09-242365 filed in the Japanese Patent Office on 09/08/1997.

Claims

A process cartridge (8) for an image forming apparatus (1) comprising an upper main body (4), said process cartridge comprising:
a cartridge main body (24) which includes at least one of a developing device (25) for developing with toner a latent image on a photoconductor (14) and a cleaner (26) for salvaging the toner remaining on a surface of the photoconductor (14)

the photoconductor (14) being supported by a support frame (7) of the upper main body (4) to which the cartridge main body is detachably mountable in order to position the process cartridge relative to the photoconductor which is already supported by the support frame (7); and

covering means (49) which, when the cartridge is mounted, is able to cover a covering area including an area beneath a lower part of the circumferential surface of the photoconductor (14) and an area beneath a lower part of a boundary between the photoconductor (14) and the developing device (25) or the cleaner (26) or both,

wherein, when the upper main body (4) performs an upward movement, the covering means (49) is configured to be moved from a siding area beneath the developing device (25) or the cleaner (26) to the covering area, wherein the cartridge main body includes a guide (50) for guiding a movement of the covering means (49) between the covering area and the siding area, said covering means (49) being downwardly concaved and said guide being downwardly arc-shaped; and

a shutter open/close device (55) for moving the covering means (49) in a direction guided by the guide (50).
The process cartridge of claim 1, wherein an upper surface of the covering means (49) is bent in a direction orthogonal to a longitudinal direction of the covering means (49) so as to form a concave at a widthwise centre part of the upper surface of the covering means (49).
The process cartridge of one of the claims 1 or 2, wherein the guide (50) is for moving the covering means (49) in cooperation with an open/close member (61) mounted to the lower main body (2) of the image forming apparatus (1).
The process cartridge of one of the claims 1 to 3, wherein said means for covering a covering area is a shutter (49).
The process cartridge (8) of claim 3 or 4, wherein said means for moving said covering means (49) is a covering means open/close device (55).
An image forming apparatus (1) comprising a process cartridge (8) according to one of the claims 1 to 5.
The image forming apparatus (1) of claim 6, further comprising:
a lower main body (3) which is located below the upper main body (4);
wherein, the upper main body (4) is connected to the lower main body (3) at one side of the lower main body (3) so as to be rotatable in up and down directions to form and close an opening between the upper and lower main bodies (4, 3) at the other side opposite the connected side of the upper main body (4), and an open/close member (61) which moves the shutter open/close device (55) in cooperation with up and down movements of the upper main body (4) is provided to the lower main body (3).
The image forming apparatus of claim 7, wherein the covering means (49) is moved to the siding area when the upper main body (4) is rotated in the down direction to close the opening between the upper and lower main bodies (4, 3) at the other side opposite the connected side of the upper main body (4).