US-12625463-B2 - Process cartridge and electrophotographic image forming apparatus

Abstract

A process cartridge includes a frame having a side surface at a side of the process cartridge. A photosensitive drum is supported by the frame, the photosensitive drum being rotatable about an axis thereof, the photosensitive drum including a first end positioned at the side of the process cartridge and a second end opposite to the first end in a direction of the axis of the photosensitive drum. A projection is positioned coaxial with the photosensitive drum and at the side of the process cartridge, with the projection projecting from the side surface of the frame in the axial direction of the photosensitive drum with at least a tip of the projection being exposed to outside of the process cartridge. A gear is positioned at the side of the process cartridge, with the gear being rotatable about an axis thereof, the gear having a plurality of teeth, with at least some of the teeth being exposed teeth that are uncovered by the frame and exposed to outside of the process cartridge, and with a tip of at least one of the exposed teeth facing the axis of the photosensitive drum.

Inventors

• Ryuta Murakami
• Tadashi Horikawa
• Shunsuke Uratani
• Yuichiro Inaba

Assignees

• CANON KABUSHIKI KAISHA

Dates

Publication Date

20260512

Application Date

20240513

Priority Date

20160614

Claims (17)

1. 1 . A process cartridge comprising: a frame including a side surface at a side of the process cartridge; a photosensitive drum supported by the frame, the photosensitive drum being rotatable about an axis thereof, the photosensitive drum including (i) a first end positioned at the side of the process cartridge and (ii) a second end opposite to the first end in an axial direction of the photosensitive drum; a projection positioned (i) coaxial with the photosensitive drum and (ii) at the side of the process cartridge, the projection projecting from the side surface of the frame in the axial direction of the photosensitive drum with at least a tip of the projection being exposed to outside of the process cartridge; a developing roller supported by the frame, the developing roller being rotatable about an axis thereof; and a gear positioned at the side of the process cartridge, the gear being rotatable about an axis thereof, the gear having a plurality of teeth, with at least some of the teeth being exposed teeth that are uncovered by the frame and exposed to outside of the process cartridge, and with a tip of at least one of the exposed teeth facing the axis of the photosensitive drum, wherein, as measured in the axial direction of the photosensitive drum, (i) the tip of the projection is positioned farther from the second end of the photosensitive drum than the first end of the photosensitive drum is positioned from the second end of the photosensitive drum, and (ii) at least a part of the exposed teeth of the gear is positioned farther from the second end of the photosensitive drum than the tip of the projection is positioned from the second end of the photosensitive drum, and wherein, as measured along a line perpendicular to the axis of the photosensitive drum, a shortest distance from the axis of the photosensitive drum to a tip of one of the plurality of teeth is 90% to 110% of a length of a radius of the photosensitive drum.
2. 2 . A process cartridge according to claim 1 , wherein the gear is a spur gear.
3. 3 . A process cartridge according to claim 2 , wherein the teeth of the spur gear are 1 mm or less in length along an axial direction of the spur gear.
4. 4 . A process cartridge according to claim 1 , wherein the teeth of the gear are 1 mm or less in length along an axial direction of the gear.
5. 5 . A process cartridge according to claim 1 , further comprising a stopper positioned at the side of the process cartridge, the stopper having a surface extending in the axial direction of the photosensitive drum and facing the axis of the photosensitive drum.
6. 6 . A process cartridge according to claim 1 , wherein the frame includes a slit at the side of the process cartridge, with the slit being open to outside of the frame (i) in a first direction that is perpendicular to the axis of the photosensitive drum and (ii) in a second direction that is perpendicular to the first direction, and wherein, when the process cartridge is oriented such that the axis of the photosensitive drum is positioned above the axis of the gear, the slit is open towards a top side of the process cartridge.
7. 7 . A process cartridge according to claim 6 , wherein at least one of the exposed teeth faces the slit.
8. 8 . A process cartridge according to claim 6 , wherein, as measured in the axial direction of the photosensitive drum, at least a part of the slit is positioned farther from the second end of the photosensitive drum than the tip of the projection is positioned from the second end of the photosensitive drum.
9. 9 . A process cartridge according to claim 6 , wherein the slit runs perpendicular to the axial direction of the photosensitive drum.
10. 10 . A process cartridge according to claim 1 , wherein the gear is a helical gear.
11. 11 . A process cartridge according to claim 10 , wherein the gear is operatively connected to the developing roller.
12. 12 . A process cartridge according to claim 10 , wherein the gear is positioned coaxial with the developing roller.
13. 13 . A process cartridge according to claim 1 , wherein the gear is operatively connected to the developing roller.
14. 14 . A process cartridge according to claim 1 , wherein the gear is positioned coaxial with the developing roller.
15. 15 . A process cartridge according to claim 1 , wherein the frame includes: a first frame supporting the photosensitive drum; and a second frame supporting the developing roller.
16. 16 . A process cartridge according to claim 1 , wherein the photosensitive drum and the developing roller are operatively connected to each other.
17. 17 . A process cartridge according to claim 1 , wherein the frame includes: a first frame supporting the photosensitive drum; and a second frame supporting the developing roller, and wherein the photosensitive drum and the developing roller are operatively connected to each other.

Description

TECHNICAL FIELD The present invention relates to a process cartridge and an electrophotographic image forming apparatus using the same. Here, the process cartridge is a cartridge which is integrally formed with a photosensitive member and a process means actable on the photosensitive member so as to be dismountably mounted to a main assembly of the electrophotographic image forming apparatus. For example, a photosensitive member and at least one of a developing means, a charging means and a cleaning means as the process means are integrally formed into a cartridge. Also, the electrophotographic image forming apparatus forms an image on a recording material using an electrophotographic image forming process. Examples of the electrophotographic image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (LED printer, laser beam printer, etc.), a facsimile machine, a word processor, and the like. BACKGROUND ART In an electrophotographic image forming apparatus (hereinafter also simply referred to as “image forming apparatus”), a drum type electrophotographic photosensitive member as an image bearing member, that is, a photosensitive drum (electrophotographic photosensitive drum) is uniformly charged. Subsequently, the charged photosensitive drum is selectively exposed to form an electrostatic latent image (electrostatic image) on the photosensitive drum. Next, the electrostatic latent image formed on the photosensitive drum is developed as a toner image with toner as developer. Then, the toner image formed on the photosensitive drum is transferred onto a recording material such as recording sheet, plastic sheet, and so on, and heat and pressure are applied to the toner image transferred onto the recording material to fix the toner image on the recording material, so that image recording is carried out. Such an image forming apparatus generally requires toner replenishment and maintenance of various process means. In order to facilitate toner replenishment and maintenance, process cartridges dismountably mountable to the image forming apparatus main assembly have been put into cartridges by integrating photosensitive drums, charging means, developing means, cleaning means and the like in the frame. With this process cartridge system, a part of the maintenance operation of the apparatus can be carried out by the user him/herself without relying on a service person in charge of after-sales service. Therefore, it is possible to improve the usability of the apparatus remarkably, and it is possible to provide an image forming apparatus excellent in usability. For this reason, this process cartridge system is widely used with image forming apparatus. As described in JP H08-328449 (page 20, FIG. 16), a well-known image forming apparatus of the type described above includes a drive transmission member having a coupling at the free end thereof for transmitting drive to the process cartridge from the main assembly of the image forming apparatus, which is spring biased toward the process cartridge. When an opening and closing door of the image forming apparatus main assembly is closed, the drive transmission member of this image forming apparatus is pressed by the spring and moves toward the process cartridge. By doing so, the drive transmission member engages (couples) with the coupling of the process cartridge and the drive transmission to the process cartridge is enabled. Also, when the opening/closing door of the image forming apparatus main assembly is opened, the drive transmission member moves in a direction away from the process cartridge against the spring by a cam. By this, the drive transmitting member disestablishes the engagement (coupling) with the coupling of the process cartridge, so that the process cartridge can be dismounted from the main assembly of the image forming apparatus. SUMMARY OF THE INVENTION Problems to be Solved by the Invention The object of the present invention is to further develop the aforementioned prior art. Means for Solving the Problem Typical structure of the invention of this application is, A process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, said process cartridge comprising a photosensitive member; a coupling portion provided at an end portion of said photosensitive member and including a driving force receiving portion for receiving a driving force for rotating said photosensitive member, from an outside of said process cartridge; and a gear portion including gear teeth for receiving a driving force from an outside of said process cartridge, independently from said coupling portion, wherein said gear teeth include an exposed portion exposed to an outside of said process cartridge, wherein at least a part of said exposed portion (a) faces an axis of said photosensitive member, (b) is disposed outside of said driving force receiving portion in an axial direction of said photosen