PROCESS CARTRIDGE COMPRISING GROUNDING, CHARGING BIAS, AND DEVELOPING BIAS CONTACTS AND INPUT AND OUTPUT CONTACTS, AND ELECTROPHOTOGRAPHIC IMAGE FORMING APPARATUS TO WHICH THE PROCESS CARTRIDG Number:6,804,475 from the United States Patent and Trademark Office (PTO) owispatent A process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus includes an electrophotographic photosensitive drum; a charging roller for charging the drum; a developing roller for developing an image formed on the drum; an input electrode; an output electrode; a grounding contact for grounding the drum; a charging bias contact receiving a charging bias voltage applied to the charging roller; a developing bias contact receiving a developing bias applied to the developing roller; an input electrical contact for receiving an input bias applied to the input electrode; and an output contact for transmitting, to the main assembly, an output corresponding to electrostatic capacities between the input and output electrodes and between the developing roller and the output electrode to detect in substantially real time a remaining amount of developer in the cartridge.<H ELECTROPHOTOGRAPHIC, DEVELOPING, PROCESS, CARTRID, 6804475.html, Patent, pto, 6804475

Title: PROCESS CARTRIDGE COMPRISING GROUNDING, CHARGING BIAS, AND DEVELOPING BIAS CONTACTS AND INPUT AND OUTPUT CONTACTS, AND ELECTROPHOTOGRAPHIC IMAGE FORMING APPARATUS TO WHICH THE PROCESS CARTRIDG

Abstract: A process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus includes an electrophotographic photosensitive drum; a charging roller for charging the drum; a developing roller for developing an image formed on the drum; an input electrode; an output electrode; a grounding contact for grounding the drum; a charging bias contact receiving a charging bias voltage applied to the charging roller; a developing bias contact receiving a developing bias applied to the developing roller; an input electrical contact for receiving an input bias applied to the input electrode; and an output contact for transmitting, to the main assembly, an output corresponding to electrostatic capacities between the input and output electrodes and between the developing roller and the output electrode to detect in substantially real time a remaining amount of developer in the cartridge.

Patent Number: 6,804,475 Issued on 10/12/2004 to Oguma, et al.

Inventors: Oguma; Toru (Mishima, JP); Karakama; Toshiyuki (Shizuoka-ken, JP); Yokoi; Akiyoshi (Shizuoka-ken, JP)
Assignee: Canon Kabushiki Kaisha (Tokyo, JP)

Appl. No.: 10/091,287

Filed: March 6, 2002

Foreign Application Priority Data


Mar 09, 2001 [JP]			2001/066213

Current U.S. Class: 399/27 ; 399/111; 399/119

Current International Class: G03G 21/18 (20060101)

Field of Search: 399/9,24,27,30,61,62,63,111,119,88,90,107

References Cited [Referenced By]

U.S. Patent Documents


4591258	May 1986	Nishino et al.
4924267	May 1990	Yoshikawa et al.
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5142322	August 1992	Surti
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5463446	October 1995	Watanabe et al.
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5614992	March 1997	Kikuchi et al.
5617579	April 1997	Yashiro et al.
5640649	June 1997	Kikuchi et al.
5652647	July 1997	Yashiro et al.
5689774	November 1997	Shishido et al.
5768660	June 1998	Kurihara et al.
5873012	February 1999	Miyabe et al.
6070028	May 2000	Odagawa et al.
6097909	August 2000	Watanabe et al.
6128452	October 2000	Miyabe et al.
6253036	June 2001	Karakama et al.
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6330402	December 2001	Sakurai et al.
6377759	April 2002	Abe et al.
2002/0012542	January 2002	Karakama, et al.

Foreign Patent Documents


0 281 372	Sep., 1988	EP
0 285 139	Oct., 1988	EP
0 466 173	Jan., 1992	EP
0 468 751	Jan., 1992	EP
0 572 738	Dec., 1993	EP
0 586 041	Mar., 1994	EP
0 586 046	Mar., 1994	EP
1 016 939	Dec., 1999	EP
2-163761	Jun., 1990	JP
4-18920	Jan., 1992	JP
6-19242	Jan., 1994	JP
6-83123	Mar., 1994	JP
6-208260	Jul., 1994	JP
6-317961	Nov., 1994	JP
2000-250380	Sep., 2000	JP
WO 92/18910	Oct., 1992	WO

Primary Examiner: Ngo; Hoang
Attorney, Agent or Firm: Fitzpatrick, Cella, Harper & Scinto

Claims

What is claimed is:

1. A process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, comprising: an electrophotographic photosensitive drum; a charging roller configured and positioned to electrically charge said electrophotographic photosensitive drum; a developing roller configured and positioned to develop an electrostatic latent image formed on said electrophotographic photosensitive drum; an input electrode extending along a longitudinal direction of said developing roller; an output electrode extending along the longitudinal direction of said developing roller; a grounding contact configured and positioned to electrically ground said photosensitive drum to the main assembly of the apparatus when said cartridge is mounted to the main assembly of the apparatus, said grounding contact being exposed at an end surface of a cartridge frame provided at one longitudinal end of said photosensitive drum and being disposed across an axis of said photosensitive drum; a charging bias contact configured and positioned to receive a charging bias voltage to be applied to said charging roller from the main assembly of the apparatus when said cartridge is mounted to the main assembly of the apparatus, said charging bias contact being exposed and facing downwardly adjacent said one longitudinal end of said photosensitive drum when said cartridge is mounted to the main assembly of the apparatus; a developing bias contact configured and positioned to receive a developing bias to be applied to said developing roller from the main assembly of the apparatus when said cartridge is mounted to the main assembly of the apparatus, said developing bias contact being exposed and facing downwardly adjacent said one longitudinal end of said photosensitive drum when said cartridge is mounted to the main assembly of the apparatus, and said developing bias contact being disposed at a side opposite from said charging bias contact with said photosensitive drum interposed therebetween with respect to a direction crossing a longitudinal direction of said photosensitive drum; an input electrical contact configured and positioned to receive an input bias to be applied to said input electrode from the main assembly of the apparatus when said cartridge is mounted to the main assembly of the apparatus, said input electrical contact being exposed at the end surface of the cartridge frame provided adjacent said one longitudinal end of said photosensitive drum; and an output electrical contact configured and positioned to transmit, to the main assembly of the apparatus, an output produced on the basis of a value corresponding to an electrostatic capacity between said input electrode and said output electrode and an electrostatic capacity between said developing roller and said output electrode so that the main assembly of the apparatus can detect in substantially real time a remaining amount of the developer in said cartridge when said cartridge is mounted to the main assembly of the apparatus, said output electrical contact being exposed at the end surface of the cartridge frame.

2. A process cartridge according to claim 1, wherein said input electrode is supplied with an AC bias voltage from said input electrical contact.

3. A process cartridge according to claim 1 or 2, wherein the cartridge frame includes a developer frame containing a developer accommodating portion configured and positioned to accommodate the developer to be used by said developing roller to develop the electrostatic latent image, a developing device frame supporting said developing roller, and a drum frame supporting said photosensitive drum and said charging roller, wherein said input electrical contact is provided on the developer frame, and said output electrical contact is provided on the developing device frame.

4. A process cartridge according to claim 3, further comprising a developer supply opening configured and positioned to supply the developer accommodated in the developer accommodating portion to said developing roller, wherein said input electrical contact and said output electrical contact are juxtaposed with a pulling path on which a developer seal sealing said developer supply opening is pulled.

5. A process cartridge according to claim 4, wherein said input electrode is provided on the developer frame, and said output electrode is provided on the developing device frame.

6. A process cartridge according to claim 5, wherein said grounding contact and said charging bias contact are provided on the drum frame, and said developing bias contact is provided on the developing device frame.

7. A process cartridge according to claim 1 or 2, wherein said developing bias contact is used also to receive from the main assembly of the apparatus a developing bias to be applied to said developing roller to detect the value corresponding to the electrostatic capacity between said developing roller and said output electrode.

8. An electrophotographic image forming apparatus for forming an image on a recording material, to which a process cartridge is detachably mountable, said apparatus comprising: (a) a main assembly grounding contact; (b) a main assembly developing bias contact; (c) a main assembly charging bias contact; (d) a main assembly input electrical contact; (e) a main assembly output input electrical contact; and (f) a mounting portion configured and positioned to detachably mount the process cartridge, the process cartridge including: an electrophotographic photosensitive drum; a charging roller configured and positioned to electrically charge the electrophotographic photosensitive drum; a developing roller configured and positioned to develop an electrostatic latent image formed on the electrophotographic photosensitive drum; an input electrode extending along a longitudinal direction of the developing roller; an output electrode extending along the longitudinal direction of the developing roller; a grounding contact configured and positioned to electrically connect with said main assembly grounding contact to electrically ground the photosensitive drum to a main assembly of said apparatus when the cartridge is mounted to the main assembly of said apparatus, the grounding contact being exposed at an end surface of a cartridge frame provided at one longitudinal end of the photosensitive drum and being disposed across an axis of the photosensitive drum; a charging bias contact configured and positioned to electrically connect with said main assembly charging bias contact to receive a charging bias voltage to be applied to the charging roller from the main assembly of said apparatus when the cartridge is mounted to the main assembly of said apparatus, the charging bias contact being exposed and facing downwardly adjacent one longitudinal end of the photosensitive drum when the cartridge is mounted to the main assembly of said apparatus; a developing bias contact configured and positioned to electrically connect with said main assembly developing bias contact to receive a developing bias to be applied to the developing roller from the main assembly of said apparatus when the cartridge is mounted to the main assembly of said apparatus, the developing bias contact being exposed and facing downwardly adjacent one longitudinal end of the photosensitive drum when the cartridge is mounted to the main assembly of said apparatus, and the developing bias contact being disposed at a side opposite from the charging bias contact with the photosensitive drum interposed therebetween with respect to a direction crossing a longitudinal direction of the photosensitive drum; an input electrical contact configured and positioned to electrically connect with said main assembly input electrical contact to receive an input bias to be applied to the input electrode from the main assembly of said apparatus when the cartridge is mounted to the main assembly of said apparatus, the input electrical contact being exposed at the end surface of the cartridge frame provided adjacent a longitudinal end of the photosensitive drum; and an output electrical contact configured and positioned to electrically connect with said main assembly output contact to transmit, to the main assembly of said apparatus, an output produced on the basis of a value corresponding to an electrostatic capacity between the input electrode and the output electrode and an electrostatic capacity between the developing roller and the output electrode so that the main assembly of said apparatus can detect in substantially real time a remaining amount of the developer in the cartridge when the cartridge is mounted to the main assembly of said apparatus, the output electrical contact being exposed at the end surface of the cartridge frame.

9. A process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, comprising: an electrophotographic photosensitive drum; a charging roller configured and positioned to electrically charge said electrophotographic photosensitive drum; a developing roller configured and positioned to develop an electrostatic latent image formed on said electrophotographic photosensitive drum; an input electrode extending along a longitudinal direction of said developing roller; an output electrode extending along a longitudinal direction of said developing roller; a grounding contact configured and positioned to electrically ground said photosensitive drum to a main assembly of the apparatus when said cartridge is mounted to the main assembly of the apparatus, said grounding contact being exposed at an end surface of a cartridge frame provided at one longitudinal end of said photosensitive drum and being disposed across an axis of said photosensitive drum; a charging bias contact configured and positioned to receive a charging bias voltage to be applied to said charging roller from the main assembly of the apparatus when said cartridge is mounted to the main assembly of the apparatus, said charging bias contact being exposed and facing downwardly adjacent one longitudinal end of said photosensitive drum when said cartridge is mounted to the main assembly of the apparatus; a developing bias contact configured and positioned to receive a developing bias to be applied to said developing roller from the main assembly of the apparatus when said cartridge is mounted to the main assembly of the apparatus, said developing bias contact being exposed and facing downwardly adjacent one longitudinal end of said photosensitive drum when said cartridge is mounted to the main assembly of the apparatus, and said developing bias contact being disposed at a side opposite from said charging bias contact with said photosensitive drum interposed therebetween with respect to a direction crossing a longitudinal direction of said photosensitive drum; an input electrical contact configured and positioned to receive an input bias to be applied to said input electrode from the main assembly of the apparatus when said cartridge is mounted to the main assembly of the apparatus, said input electrical contact being exposed at an end surface of the cartridge frame provided adjacent a longitudinal end of said photosensitive drum; and an output electrical contact configured and positioned to transmit, to the main assembly of the apparatus, an output produced on the basis of a value corresponding to an electrostatic capacity between said input electrode and said output electrode and an electrostatic capacity between said developing roller and said output electrode so that the main assembly of the apparatus can detect in substantially real time a remaining amount of the developer in said cartridge when said cartridge is mounted to the main assembly of the apparatus, said output electrical contact being exposed at an end surface of the cartridge frame, wherein the cartridge frame includes a developer frame containing a developer accommodating portion configured and positioned to accommodate the developer to be used by said developing roller to develop the electrostatic latent image, a developing device frame supporting said developing roller, and a drum frame supporting said photosensitive drum and a charging roller, wherein said input electrical contact is provided on the developer frame, and said output electrical contact is provided on the developing device frame, and wherein said developing bias contact is used also to receive from the main assembly of the apparatus a developing bias to be applied to said developing roller to detect the value corresponding to the electrostatic capacity between said developing roller and said output electrode.

10. A process cartridge according to claim 9, wherein said input electrode is supplied with an AC bias voltage from said input electrical contact.

11. A process cartridge according to claim 9 or 10, further comprising a developer supply opening configured and positioned to supply the developer accommodated in the developer accommodating portion to the developing roller, wherein the input electrical contact and the output electrical contact are juxtaposed with a pulling path on which a developer seal sealing said developer supply opening is pulled.

12. A process cartridge according to claim 9 or 10, wherein the input electrode is provided on the developer frame, and the output electrode is provided on the developing device frame.

13. A process cartridge according to claim 12, wherein the grounding contact and the charging bias contact are provided on the drum frame, and the developing bias contact is provided on the developing device frame.

14. An electrophotographic image forming apparatus for forming an image on a recording material, to which a process cartridge is detachably mountable, said apparatus comprising: (a) a main assembly grounding contact; (b) a main assembly developing bias contact; (c) a main assembly charging bias contact; (d) a main assembly input electrical contact; (e) a main assembly output input electrical contact; and (f) a mounting portion configured and positioned to detachably mount the process cartridge, the process cartridge including: an electrophotographic photosensitive drum; a charging roller configured and positioned to electrically charge the electrophotographic photosensitive drum; a developing roller configured and positioned to develop an electrostatic latent image formed on the electrophotographic photosensitive drum; an input electrode extending along a longitudinal direction of the developing roller; an output electrode extending along a longitudinal direction of the developing roller; a grounding contact configured and positioned to electrically connect with said main assembly grounding contact to electrically ground the photosensitive drum to a main assembly of said apparatus when the cartridge is mounted to the main assembly of said apparatus, the grounding contact being exposed at an end surface of a cartridge frame provided at one longitudinal end of the photosensitive drum and being disposed across an axis of the photosensitive drum; a charging bias contact configured and positioned to electrically connect with said main assembly charging bias contact to receive a charging bias voltage to be applied to the charging roller from the main assembly of said apparatus when the cartridge is mounted to the main assembly of said apparatus, the charging bias contact being exposed and facing downwardly adjacent one longitudinal end of the photosensitive drum when the cartridge is mounted to the main assembly of said apparatus; a developing bias contact configured and positioned to electrically connect with said main assembly developing bias contact to receive a developing bias to be applied to the developing roller from the main assembly of said apparatus when the cartridge is mounted to the main assembly of said apparatus, the developing bias contact being exposed and facing downwardly adjacent one longitudinal end of the photosensitive drum when the cartridge is mounted to the main assembly of said apparatus, and the developing bias contact being disposed at a side opposite from the charging bias contact with the photosensitive drum interposed therebetween with respect to a direction crossing a longitudinal direction of the photosensitive drum; an input electrical contact configured and positioned to electrically connect with said main assembly input electrical contact to receive an input bias to be applied to the input electrode from the main assembly of said apparatus when the cartridge is mounted to the main assembly of said apparatus, the input electrical contact being exposed at an end surface of the cartridge frame provided adjacent a longitudinal end of the photosensitive drum; and an output electrical contact configured and positioned to electrically connect with said main assembly output contact to transmit, to the main assembly of said apparatus, an output produced on the basis of a value corresponding to an electrostatic capacity between the input electrode and the output electrode and an electrostatic capacity between the developing roller and the output electrode so that the main assembly of said apparatus can detect in substantially real time a remaining amount of the developer in the cartridge when the cartridge is mounted to the main assembly of said apparatus, the output electrical contact being exposed at an end surface of the cartridge frame, wherein the cartridge frame includes a developer frame containing a developer accommodating portion configured and positioned to accommodate the developer to be used by the developing roller to develop the electrostatic latent image, a developing device frame supporting the developing roller, and a drum frame supporting the photosensitive drum and a charging roller, wherein the input electrical contact is provided on the developer frame, and the output electrical contact is provided on the developing device frame, and wherein the developing bias contact is used also to receive from the main assembly of said apparatus a developing bias to be applied to the developing roller to detect the value corresponding to the electrostatic capacity between the developing roller and the output electrode.

15. A process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, comprising: an electrophotographic photosensitive drum; a charging roller configured and positioned to electrically charge said electrophotographic photosensitive drum; a developing roller configured and positioned to develop an electrostatic latent image formed on said electrophotographic photosensitive drum; an input electrode extending along a longitudinal direction of said developing roller; an output electrode extending along a longitudinal direction of said developing roller; a grounding contact configured and positioned to electrically ground said photosensitive drum to the main assembly of the apparatus when said cartridge is mounted to the main assembly of the apparatus, said grounding contact being exposed at an end surface of a cartridge frame provided at one longitudinal end of said photosensitive drum and being disposed across an axis of said photosensitive drum; a charging bias contact configured and positioned to receive a charging bias voltage to be applied to said charging roller from the main assembly of the apparatus when said cartridge is mounted to the main assembly of the apparatus, said charging bias contact being exposed and facing downwardly adjacent one longitudinal end of said photosensitive drum when said cartridge is mounted to the main assembly of the apparatus; a developing bias contact configured and positioned to receive a developing bias to be applied to said developing roller from the main assembly of the apparatus when said cartridge is mounted to the main assembly of the apparatus, said developing bias contact being exposed and facing downwardly adjacent one longitudinal end of said photosensitive drum when said cartridge is mounted to the main assembly of the apparatus, and said developing bias contact being disposed at a side opposite from said charging bias contact with said photosensitive drum interposed therebetween with respect to a direction crossing a longitudinal direction of said photosensitive drum; an input electrical contact configured and positioned to receive an input bias to be applied to said input electrode from the main assembly of the apparatus when said cartridge is mounted to the main assembly of the apparatus, said input electrical contact being exposed at an end surface of the cartridge frame provided adjacent a longitudinal end of said photosensitive drum; and an output electrical contact configured and positioned to transmit, to the main assembly of the apparatus, an output produced on the basis of a value corresponding to an electrostatic capacity between said input electrode and said output electrode and an electrostatic capacity between said developing roller and said output electrode so that the main assembly of the apparatus can detect in substantially real time a remaining amount of the developer in said cartridge when said apparatus when said cartridge is mounted to the main assembly of the apparatus, said output electrical contact being exposed at an end surface of the cartridge frame, wherein the cartridge frame includes a developer frame containing a developer accommodating portion configured and positioned to accommodate the developer to be used by said developing roller to develop the electrostatic latent image, a developing device frame supporting said developing roller, and a drum frame supporting said photosensitive drum and a charging roller, wherein said input electrical contact is provided on the developer frame, and said output electrical contact is provided on the developing device frame, said process cartridge further comprising a developer supply opening configured and positioned to supply the developer accommodated in the developer accommodating portion to said developing roller, wherein said input electrical contact and said output electrical contact are juxtaposed with a pulling path on which a developer seal sealing said developer supply opening is pulled, wherein said input electrode is provided on the developer frame, and said output electrode is provided on the developing device frame, wherein said grounding contact and said charging bias contact are provided on the drum frame, and said developing bias contact is provided on the developing device frame, and wherein said developing bias contact is used also to receive from the main assembly of the apparatus a developing bias to be applied to said developing roller to detect the value corresponding to the electrostatic capacity between said developing roller and said output electrode.

16. A process cartridge according to claim 15, wherein said input electrode is supplied with an AC bias voltage from said input electrical contact.

17. An electrophotographic image forming apparatus for forming an image on a recording material, to which a process cartridge is detachably mountable, said apparatus comprising: (a) a main assembly grounding contact; (b) a main assembly developing bias contact; (c) a main assembly charging bias contact; (d) a main assembly input electrical contact; (e) a main assembly output input electrical contact; and (f) a mounting portion for detachably mounting the process cartridge, the process cartridge including: an electrophotographic photosensitive drum; a charging roller configured and positioned to electrically charge the electrophotographic photosensitive drum; a developing roller configured and positioned to develop an electrostatic latent image formed on the electrophotographic photosensitive drum; an input electrode extending along a longitudinal direction of the developing roller; an output electrode extending along a longitudinal direction of the developing roller; a grounding contact configured and positioned to electrically connect with said main assembly grounding contact to electrically ground the photosensitive drum to a main assembly of said apparatus when the cartridge is mounted to the main assembly of said apparatus, the grounding contact being exposed at an end surface of a cartridge frame provided at one longitudinal end of the photosensitive drum and being disposed across an axis of the photosensitive drum; a charging bias contact configured and positioned to electrically connect with said main assembly charging bias contact to receive a charging bias voltage to be applied to the charging roller from the main assembly of said apparatus when the cartridge is mounted to the main assembly of said apparatus, the charging bias contact being exposed and facing downwardly adjacent one longitudinal end of the photosensitive drum when the cartridge is mounted to the main assembly of said apparatus; a developing bias contact configured and positioned to electrically connect with said main assembly developing bias contact to receive a developing bias to be applied to the developing roller from the main assembly of said apparatus when the cartridge is mounted to the main assembly of said apparatus, the developing bias contact being exposed and facing downwardly adjacent one longitudinal end of the photosensitive drum when the cartridge is mounted to the main assembly of said apparatus, and the developing bias contact being disposed at a side opposite from the charging bias contact with the photosensitive drum interposed therebetween with respect to a direction crossing a longitudinal direction of the photosensitive drum; an input electrical contact configured and positioned to electrically connect with said main assembly input electrical contact to receive an input bias to be applied to the input electrode from the main assembly of said apparatus when the cartridge is mounted to the main assembly of said apparatus, the input electrical contact being exposed at an end surface of the cartridge frame provided adjacent a longitudinal end of the photosensitive drum; and an output electrical contact configured and positioned to electrically connect with said main assembly output contact to transmit, to the main assembly of said apparatus, an output produced on the basis of a value corresponding to an electrostatic capacity between the input electrode and the output electrode and an electrostatic capacity between the developing roller and the output electrode so that the main assembly of said apparatus can detect in substantially real time a remaining amount of the developer in the cartridge when the cartridge is mounted to the main assembly of said apparatus, the output electrical contact being exposed at an end surface of the cartridge frame, wherein the cartridge frame includes a developer frame containing a developer accommodating portion configured and positioned to accommodate the developer to be used by the developing roller to develop the electrostatic latent image, a developing device frame supporting the developing roller, and a drum frame supporting the photosensitive drum and a charging roller, wherein the input electrical contact is provided on the developer frame, and the output electrical contact is provided on the developing device frame, said process cartridge further comprising a developer supply opening configured and positioned to supply the developer accommodated in the developer accommodating portion to the developing roller, wherein the input electrical contact and the output electrical contact are juxtaposed with a pulling path on which a developer seal sealing said developer supply opening is pulled, wherein the input electrode is provided on the developer frame, and the output electrode is provided on the developing device frame, wherein the grounding contact and the charging bias contact are provided on the drum frame, and the developing bias contact is provided on the developing device frame, and wherein the developing bias contact is used also to receive from the main assembly of said apparatus a developing bias to be applied to the developing roller to detect the value corresponding to the electrostatic capacity between the developing roller and the output electrode.

18. A process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, comprising: an electrophotographic photosensitive drum; a charging roller configured and positioned to electrically charge said electrophotographic photosensitive drum; a developing roller configured and positioned to develop an electrostatic latent image formed on said electrophotographic photosensitive drum; an input electrode extending along a longitudinal direction of said developing roller; an output electrode extending along a longitudinal direction of said developing roller; a grounding contact configured and positioned to electrically ground said photosensitive drum to the main assembly of the apparatus when said cartridge is mounted to the main assembly of the apparatus, said grounding contact being exposed to an end surface of a cartridge frame provided at one longitudinal end of said photosensitive drum and being disposed across an axis of said photosensitive drum; a charging bias contact configured and positioned to receive a charging bias voltage to be applied to said charging roller from the main assembly of the apparatus when said cartridge is mounted to the main assembly of the apparatus, said charging bias contact being exposed and facing downwardly adjacent one longitudinal end of said photosensitive drum when said cartridge is mounted to the main assembly of the apparatus; a developing bias contact configured and positioned to receive a developing bias to be applied to said developing roller from the main assembly of the apparatus when said cartridge is mounted to the main assembly of the apparatus, said developing bias contact being exposed and facing downwardly adjacent one longitudinal end of said photosensitive drum when said cartridge is mounted to the main assembly of the apparatus, and said developing bias contact being disposed at a side opposite from said charging bias contact with said photosensitive drum interposed therebetween with respect to a direction crossing a longitudinal direction of said photosensitive drum; an input electrical contact configured and positioned to receive an input bias to be applied to said input electrode from the main assembly of the apparatus when said cartridge is mounted to the main assembly of the apparatus, said input electrical contact being exposed at an end surface of the cartridge frame provided adjacent a longitudinal end of said photosensitive drum; and an output electrical contact configured and positioned to transmit, to the main assembly of the apparatus, an output produced on the basis of a value corresponding to an electrostatic capacity between said input electrode and said output electrode and an electrostatic capacity between said developing roller and said output electrode so that the main assembly of the apparatus can detect in substantially real time a remaining amount of the developer in said cartridge when said cartridge is mounted to the main assembly of the apparatus, said output electrical contact being exposed at an end surface of the cartridge frame, wherein said input electrode is supplied with an AC bias voltage from said input electrical contact, wherein the cartridge frame includes a developer frame containing a developer accommodating portion configured and positioned to accommodate the developer to be used by said developing roller to develop the electrostatic latent image, a developing device frame supporting said developing roller, and a drum frame supporting said photosensitive drum and a charging roller, wherein said input electrical contact is provided on the developer frame, and said output electrical contact is provided on the developing device frame, said process cartridge further comprising a developer supply opening configured and positioned to supply the developer accommodated in the developer accommodating portion to said developing roller, wherein said input electrical contact and said output electrical contact are juxtaposed with a pulling path on which a developer seal sealing said developer supply opening is pulled, wherein said input electrode is provided on the developer frame, and said output electrode is provided on the developing device frame, wherein said grounding contact and said charging bias contact are provided on the drum frame, and said developing bias contact is provided on the developing device frame, and wherein said developing bias contact is used also to receive from the main assembly of the apparatus a developing bias to be applied to said developing roller to detect the value corresponding to the electrostatic capacity between said developing roller and said output electrode.

19. An electrophotographic image forming apparatus for forming an image on a recording material, to which a process cartridge is detachably mountable, said apparatus comprising: (a) a main assembly grounding contact; (b) a main assembly developing bias contact; (c) a main assembly charging bias contact; (d) a main assembly input electrical contact; (e) a main assembly output input electrical contact; and (f) a mounting portion configured and positioned to detachably mount the process cartridge, the process cartridge including: an electrophotographic photosensitive drum; a charging roller configured and positioned to electrically charge the electrophotographic photosensitive drum; a developing roller configured and positioned to develop an electrostatic latent image formed on the electrophotographic photosensitive drum; an input electrode extending along a longitudinal direction of the developing roller; an output electrode extending along a longitudinal direction of the developing roller; a grounding contact configured and positioned to electrically connect with said main assembly grounding contact to electrically ground the photosensitive drum to a main assembly of said apparatus when the cartridge is mounted to the main assembly of said apparatus, the grounding contact being exposed at an end surface of a cartridge frame provided at one longitudinal end of the photosensitive drum and being disposed across an axis of the photosensitive drum; a charging bias contact configured and positioned to electrically connect with said main assembly charging bias contact to receive a charging bias voltage to be applied to the charging roller from the main assembly of said apparatus when the cartridge is mounted to the main assembly of said apparatus, the charging bias contact being exposed and facing downwardly adjacent one longitudinal end of the photosensitive drum when the cartridge is mounted to the main assembly of said apparatus; a developing bias contact configured and positioned to electrically contact with said main assembly developing bias contact receiving a developing bias to be applied to the developing roller from the main assembly of said apparatus when the cartridge is mounted to the main assembly of said apparatus, the developing bias contact being exposed and facing downwardly adjacent one longitudinal end of the photosensitive drum when the cartridge is mounted to the main assembly of said apparatus, and the developing bias contact being disposed at a side opposite from the charging bias contact with the photosensitive drum interposed therebetween with respect to a direction crossing a longitudinal direction of the photosensitive drum; an input electrical contact configured and positioned to electrically connect with said main assembly input electrical contact to receive an input bias to be applied to the input electrode from the main assembly of said apparatus when the cartridge is mounted to the main assembly of said apparatus, said input electrical contact being exposed at an end surface of the cartridge frame provided adjacent a longitudinal end of the photosensitive drum; and an output electrical contact configured and positioned to electrically connect with said main assembly output contact to transmit, to the main assembly of said apparatus, an output produced on the basis of a value corresponding to an electrostatic capacity between the input electrode and the output electrode and an electrostatic capacity between the developing roller and the output electrode so that the main assembly of said apparatus can detect in substantially real time a remaining amount of the developer in the cartridge when the cartridge is mounted to the main assembly of said apparatus, the output electrical contact being exposed at an end surface of the cartridge frame, wherein the input electrode is supplied with an AC bias voltage from the input electrical contact, wherein the cartridge frame includes a developer frame containing a developer accommodating portion configured and positioned to accommodate the developer to be used by the developing roller to develop the electrostatic latent image, a developing device frame supporting the developing roller, and a drum frame supporting the photosensitive drum and a charging roller, wherein the input electrical contact is provided on the developer frame, and the output electrical contact is provided on the developing device frame, said process cartridge further comprising a developer supply opening configured and positioned to supply the developer accommodated in the developer accommodating portion to the developing roller, wherein the input electrical contact and the output electrical contact are juxtaposed with a pulling path on which a developer seal sealing said developer supply opening is pulled, wherein the input electrode is provided on the developer frame, and the output electrode is provided on the developing device frame, wherein the grounding contact and the charging bias contact are provided on the drum frame, and the developing bias contact is provided on the developing device frame, and wherein the developing bias contact is used also to receive from the main assembly of said apparatus a developing bias to be applied to the developing roller to detect the value corresponding to the electrostatic capacity between the developing roller and said the output electrode.

Description

FIELD OF THE INVENTION AND RELATED ART

The present invention relates to a process cartridge and an electrophotographic image forming apparatus.

An electrophotographic image forming apparatus is an apparatus which forms an image on recording medium with the use of an electrophotographic image formation method. As for the examples of an electrophotographic image forming apparatus, an electrophotographic copying machine, an electrophotographic printer (laser beam printer, LED printer, or the like), a facsimile machine, a word processor, or the like, are included.

A process cartridge is a cartridge in which a charging means, a developing means or cleaning means, and an electrophotographic photoconductive drum, are integrally disposed, and which is removably mountable in the main assembly of an electrophotographic image forming apparatus. It also is a cartridge in which at least one means among a charging means, a developing means, and a cleaning means, and an electrophotographic photoconductive drum, are integrally disposed, and which is removably mountable in the main assembly of an electrophotographic image forming apparatus, or a cartridge in which a minimum of a developing means, and an electrophotographic photoconductive member, are integrally disposed, and which is removably mountable in the main assembly of an electrophotographic image forming apparatus.

An electrophotographic image forming apparatus, which employs an electrophotographic image formation process, also employs a process cartridge system, in which an electrophotographic photoconductive member, and a single, or a plurality of, processing means, which act on the electrophotographic photoconductive drum, are integrally disposed in a cartridge which is removably mountable in the main assembly of an electrophotographic image forming apparatus. This system enables a user to maintain the apparatus without relying on service personnel, drastically improving operational efficiency. Thus, a process cartridge system is widely in use in the field of an electrophotographic image forming apparatus.

In the case of an electrophotographic image forming apparatus employing a process cartridge system, a user him/herself replaces a cartridge. Therefore, some of the electrophotographic image forming apparatuses are equipped with a developer amount detecting means for informing the user of the remaining amount of the developer. As for a developer amount detecting means, there is a method in which a plurality of electrodes are disposed within a process cartridge, and the changes in the electrostatic capacity among the electrodes are detected to estimate the remaining amount of the developer.

According to a process cartridge system, as a cartridge is inserted into the apparatus main assembly, an electrical connection must be established between the cartridge and apparatus main assembly. Therefore, a cartridge is provided with electrical contacts (for example, U.S. Pat. No. 6,272,299).

According to U.S. Pat. No. 6,272,299, the electrical contacts are optimally positioned to reduce in size a process cartridge and an electrophotographic image forming apparatus.

The present invention is a result of the further development of the aforementioned prior arts regarding the positioning of the electrical contacts of a process cartridge and an electrophotographic image forming apparatus.

SUMMARY OF THE INVENTION

The primary object of the present invention is to provide a smaller process cartridge which contains input and output electrical contacts which make it possible for the remaining amount of the developer to be continually detected by the image forming apparatus main assembly side, and an electrophotographic image forming apparatus in which such a process cartridge can be removably mounted.

Another object of the present invention is to provide a smaller process cartridge, which contains input and output electrical contacts which make it possible for the remaining amount of the developer to be continually detected by the image forming apparatus main assembly side, and in which the input and output electrical contacts are positioned at one of the lengthwise ends of the process cartridge to improve the accuracy with which the remaining amount of the developer is detected by the image forming apparatus main assembly side, and an electrophotographic image forming apparatus in which such a process cartridge can be removably mounted.

Another object of the present invention is to provide a smaller process cartridge, the size of which is realized by optimally positioning the electrical contacts, inclusive of both input and output electrical contacts, and an electrophotographic image forming apparatus in which such a process cartridge can be removably mountable.

Another object of the present invention is to provide a process cartridge in which various electrodes thereof are disposed at one end of the process cartridge in terms of the lengthwise direction of the electrophotographic photoconductive member to make it possible to reduce the size of the high voltage circuit on the image forming apparatus main assembly side, and an electrophotographic image forming apparatus in which such a process cartridge can be removably mounted.

According to an aspect of the present invention, there is provided a process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus comprising an electrophotographic photosensitive drum; a charging roller for electrically charging the electrophotographic photosensitive drum; a developing roller for developing an electrostatic latent image formed on the electrophotographic photosensitive drum; an input electrode extending along a longitudinal direction of the developing roller; an output electrode extending along a longitudinal direction of the developing roller; a grounding contact for electrically grounding the photosensitive drum to a main assembly of the apparatus when the cartridge is mounted to the main assembly of the apparatus, the grounding contact being exposed at an end surface of a cartridge frame provided at one longitudinal end of the photosensitive drum and being disposed across an axis of the photosensitive drum; a charging bias contact for receiving a charging bias voltage to be applied to the charging roller from the main assembly of the apparatus when the cartridge is mounted to the main assembly of the apparatus, the charging bias contact being exposed and facing downwardly adjacent one longitudinal end of the photosensitive drum when the cartridge is mounted to the main assembly of the apparatus; a developing bias contact for receiving a developing bias to be applied to the developing roller from the main assembly of the apparatus when the cartridge is mounted to the main assembly of the apparatus, the developing bias contact being exposed and facing downwardly adjacent one longitudinal end of the photosensitive drum when the cartridge is mounted to the main assembly of the apparatus, and the developing bias contact being disposed at a side opposite from the charging bias contact with the photosensitive drum interposed therebetween with respect to a direction crossing a longitudinal direction of the photosensitive drum; an input electrical contact for receiving an input bias to be applied to the input electrode from the main assembly of the apparatus when the cartridge is mounted to the main assembly of the apparatus, the input electrical contact being exposed at an end surface of a cartridge frame provided adjacent a longitudinal end of the photosensitive drum; and an output contact for transmitting, to the main assembly of the apparatus, an output produced on the basis of a value corresponding to an electrostatic capacity between the input electrode and the output electrode and an electrostatic capacity between the developing roller and the output electrode to detect in substantially real time the remaining amount of the developer in the cartridge by the main assembly of the apparatus when the cartridge is mounted to the main assembly of the apparatus, the output contact being exposed at an end surface of a cartridge frame provided adjacent a longitudinal end of the photosensitive drum.

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

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view of an electrophotographic image forming apparatus in an embodiment of the present invention.

FIG. 2 is a sectional view of the process cartridge in the embodiment of the present invention.

FIG. 3 is a perspective view of the top portion of the image forming apparatus in the embodiment of the present invention, the cover of which is open.

FIG. 4 is a perspective view of the cleaning unit in the embodiment of the present invention, as seen from below.

FIG. 5 is a sectional view of the grounding electrical contact of the photoconductive drum in the embodiment of the present invention, for showing the structure thereof.

FIG. 6 is a sectional view of the charge bias electrical contact in the embodiment of the present invention, for showing the structure thereof.

FIG. 7 is a diagram of the developer amount detection circuit in the embodiment of the present invention.

FIG. 8 is a partially exploded perspective view of the developing means holding frame in the embodiment of the present invention, for showing how the first and third electrodes are attached to the developing means holding frame.

FIG. 9 is a partially exploded perspective view of the developing means holding frame in the embodiment of the present invention, for showing how the second electrode is attached to the developing means holding frame.

FIG. 10 is a perspective view of the developing holding frame and developer container in the embodiment of the present invention, for showing how the developing means holding frame and developer container are joined with each other after the attachment of the first to third electrodes to the developing means holding frame.

FIG. 11 is a side view of the process cartridge B, for showing the positioning of the external electrical contacts.

FIG. 12 is a perspective view of the process cartridge B as seen from below.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiment 1

General Description of Image Forming Apparatus

First, an example of an electrophotographic image forming apparatus in which a process cartridge in accordance with the present invention is removably mountable will be described. FIG. 1 is a sectional view of the electrophotographic image forming apparatus A in this embodiment of the present invention, and FIG. 2 is a sectional view of the process cartridge B in this embodiment.

The image forming apparatus A has an electrophotographic photoconductive drum 7 (which hereinafter will be referred to as photoconductive drum). The photoconductive drum 7 is charged by a charge roller 8 as a charging means, and is exposed to a beam of laser light emitted, while being modulated with the image formation information, from an optical means 1 comprising a laser diode, a polygon mirror, a lens, a deflection mirror, and the like. As a result, an electrostatic latent image in accordance with the image formation information, is formed on the peripheral surface of the photoconductive drum 7. This latent image is developed into a developer image, or a visible image, by a developing means.

The developing means comprises a development roller 12 as a developer bearing member for delivering developer to the photoconductive drum 7, and a development blade 18 as a regulating member for regulating the amount by which developer is adhered to the peripheral surface of the development roller 12. The developing means also comprises a developing means holding frame 13 for holding the development roller 12 and development blade 18, and a developer holding frame 11 for holding developer. The developing means holding frame 13 in which the development roller 12 and development blade 18 are held, and the developer holding frame 11 in which developer is held, are joined to form a development unit 20 or a developing apparatus.

The developing means holding frame 13 has a development chamber 13a.