Image forming apparatus performing selective driving force transmission to mounted process cartridges

• US 7,826,773 B2
• Filed: 01/10/2007
• Issued: 11/02/2010
• Est. Priority Date: 01/11/2006
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kawamura, Koji
• Primary Examiner(s): BEATTY, ROBERT B
• Application Number:
  US11/621,780
• Publication Number:
  US 20070177899A1
• Time in Patent Office: 1,392 Days
• Field of Search: 399/223, 399/228, 399/298, 399/299, 399/54
• US Class Current: 399/228
• CPC Class Codes: G03G 15/0121 for developing
• CPC Class Codes: G03G 15/0896 Arrangements or disposition of the complete developer unit or parts thereof not provided for by groups G03G15/08 - G03G15/0894
• CPC Class Codes: G03G 2221/1657 transmitting mechanical drive power

Abstract

An image forming apparatus detachably mounts black and non-black cartridges each including a photosensitive drum and a developing roller. The apparatus includes a driving source; first and second clutches for connecting and disconnecting between the driving source and the developing roller of the black and non-black cartridges, respectively; movable first and second members actable on the first and second clutches, respectively, for switching between transmitting the driving force to the developing rollers and not transmitting the driving force; and a switching member, movable by the driving force of the driving source and actable on the first and second members for switching among first, second, and third modes for transmitting the driving force to the developing rollers of all of the cartridges, not transmitting the driving force to any one of the rollers, and transmitting the driving force only to the developing roller of the black cartridge.

Claims

1. An image forming apparatus for forming a color image on a recording material, comprising:

(i) mounting means for detachably mounting a plurality of process cartridges each including a photosensitive drum and a developing roller for developing an electrostatic latent image formed on said photosensitive drum, said process cartridges including a black process cartridge containing a black color developer and a non-black process cartridge containing a non-black developer;

(ii) a driving source;

(iii) a first clutch for connecting and disconnecting between said driving source and said developing roller for selective driving force transmission to the black process cartridge;

(iv) a second clutch for connecting and disconnecting between said driving source and said developing roller for selective driving force transmission to the non-black process cartridge;

(v) a movable first member actable on said first clutch for switching between an operation state for transmitting the driving force to said developing roller and a non-operation state not transmitting the driving force thereto;

(vi) a movable second member, actable on said second clutch, for switching between an operation state for transmitting the driving force to said developing roller and a non-operation state not transmitting the driving force thereto;

(vii) a switching member, movable by the driving force of said driving source and actable on said first member and second member, for switching among a first mode for transmitting the driving force to said developing rollers of all of said process cartridges, a second mode for not transmitting the driving force to any one of said developing rollers, and a third mode for transmitting the driving force only to said developing roller of said black process cartridge, wherein said switching member includes a rotatable shaft portion, a first cam portion for contacting said first member to move said first member, said first cam portion being rotatable with said shaft portion, and a second cam portion for contacting said second member to move said second member, said second cam portion being rotatable with said shaft portion; and

(viii) a third clutch for connecting and disconnecting between said driving source and said shaft portion for selective transmission of the driving force, wherein said third clutch is capable of stopping said shaft portion for each predetermined angle within one full turn of said shaft portion.

2. An apparatus according to claim 1, wherein said first cam portion and said second cam portion is rotatable only in a predetermined direction.

3. An apparatus according to claim 1, wherein said first cam portion and said second cam portion are integral with each other.

4. An apparatus according to claim 1, wherein the predetermined angle is 90°

.

5. An apparatus according to claim 1, wherein said predetermined angle is 120°

.

6. An apparatus according to claim 1, wherein said driving source includes one motor capable of transmitting the driving force to said plurality of process cartridges.

7. An apparatus according to claim 1, wherein said driving source includes motors for supplying the driving force to said process cartridges, respectively.

8. An image forming apparatus for forming a color image on a recording material, comprising:

(i) mounting means for detachably mounting a plurality of process cartridges each including a photosensitive drum, a developing roller for developing an electrostatic latent image formed on said photosensitive drum, a first frame for rotatably supporting said photosensitive drum and a second frame for rotatably supporting said developing roller, said second frame being movable relative to said first frame to contact said developing roller to said photosensitive drum and spacing said developing roller from said photosensitive drum, said process cartridges including a black process cartridge containing a black color developer and a non-black process cartridge containing a non-black developer;

(ii) a driving source;

(iii) a first clutch for connecting and disconnecting between said driving source and said developing roller for selective driving force transmission to the black process cartridge;

(iv) a second clutch for connecting and disconnecting between said driving source and said developing roller for selective driving force transmission to the non-black process cartridge;

(v) a first member for switching between an operation state for acting on said first clutch and on said second frame of said black process cartridge to contact said photosensitive drum and said developing roller to each other and transmit the driving force to said developing roller in said black process cartridge, and a non-operation state not transmitting the driving force thereto;

(vi) a second member for acting on said second clutch and on said second frame of said non-black process cartridge and for switching between an operation state to contact said photosensitive drum and said developing roller to each other and transmit the driving force to said developing roller in said non-black process cartridge, and a non-operation state in which said photosensitive drum and said developing roller are spaced from each other so as not to transmit the driving force thereto;

(vii) a switching member, movable by the driving force of said driving source and actable on said first member and second member, for switching among a first mode for contacting said developing rollers to said photosensitive drums, respectively and for transmitting the driving force to said developing rollers of all of said process cartridges, a second mode for spacing said developing rollers from said photosensitive drums and for not transmitting the driving force to any one of said developing rollers, and a third mode for contacting said developing roller to said photosensitive drum and for transmitting the driving force only to said developing roller of said black process cartridge, wherein said switching member includes a rotatable shaft portion, a first cam portion for contacting said first member to move said first member, said first cam portion being rotatable with said shaft portion, and a second cam portion for contacting said second member to move said second member, said second cam portion being rotatable with said shaft portion; and

(viii) a third clutch for connecting and disconnecting between said driving source and said shaft portion for selective transmission of the driving force, wherein said third clutch is capable of stopping said shaft portion for each predetermined angle within one full turn of said shaft portion.

9. An apparatus according to claim 8, wherein said first cam portion and said second cam portion is rotatable only in a predetermined direction.

10. An apparatus according to claim 8, wherein said first cam portion and said second cam portion are integral with each other.

11. An apparatus according to claim 8, wherein the predetermined angle is 90°

.

12. An apparatus according to claim 8, wherein the predetermined angle is 120°

.

13. An apparatus according to claim 8, wherein said driving source includes one motor capable of transmitting the driving force to said plurality of process cartridges.

14. An apparatus according to claim 8, wherein said driving source includes motors for supplying the driving force to said process cartridges, respectively.

15. An image forming apparatus for forming a color image on a recording material, comprising:

(i) mounting means for detachably mounting a plurality of process cartridges each including a photosensitive drum, a developing roller for developing an electrostatic latent image formed on said photosensitive drum, a first frame for rotatably supporting said photosensitive drum and a second frame for rotatably supporting said developing roller, said second frame being movable relative to said first frame to contact said developing roller to said photosensitive drum and spacing said developing roller from said photosensitive drum, said process cartridges including a black process cartridge containing a black color developer and a non-black process cartridge containing a non-black developer;

(ii) a driving source;

(iii) a first clutch for connecting and disconnecting between said driving source and said developing roller for selective driving force transmission to the black process cartridge;

(iv) a second clutch for connecting and disconnecting between said driving source and said developing roller for selective driving force transmission to the non-black process cartridge;

(v) a movable first member actable on said first clutch for switching between an operation state for transmitting the driving force to said developing roller and a non-operation state not transmitting the driving force thereto;

(vi) a movable second member, actable on said second clutch, for switching between an operation state for transmitting the driving force to said developing roller and a non-operation state not transmitting the driving force thereto;

(vii) a movable third member, actable on said second frame of said black process cartridge, for switching between a state in which said photosensitive drum and said developing roller are contacted to each other, and a state in which said photosensitive drum and said developing roller are spaced from each other;

(viii) a fourth member, actable on said second frame of said non-black process cartridge, for switching between a state in which said photosensitive drum and said developing roller are contacted to each other, and a state in which said photosensitive drum and said developing roller are spaced from each other; and

(ix) a switching member, movable by the driving force of said driving source and actable on said first member, said second member, said third member and said fourth member, for switching among a first mode for contacting said developing rollers to said photosensitive drums, respectively and for transmitting the driving force to said developing rollers of all of said process cartridges, a second mode for spacing said developing rollers from said photosensitive drums and for not transmitting the driving force to any one of said developing rollers, and a third mode for contacting said developing roller to said photosensitive drum and for transmitting the driving force only to said developing roller of said black process cartridge, wherein said switching member includes a rotatable shaft portion, a first switching portion for acting on said first member and said second member, said first switching portion being rotatable with said shaft portion, and a second switching portion for acting on said third member and said fourth member, said second switching portion being rotatable with said shaft portion; and

(x) a third clutch for connecting and disconnecting between said driving source and said shaft portion for selective transmission of the driving force, wherein said third clutch is capable of stopping said shaft portion for each predetermined angle within one full turn of said shaft portion.

16. An apparatus according to claim 15, wherein said first switching including a first cam portion for contacting to said first member to move said first member;

a second cam portion for contacting to said second member to move said second member; and

wherein said second switching portion includes a third cam portion for contacting to said third member to move said first member; and

a fourth cam portion for contacting to said fourth member to move said second member.

17. An apparatus according to claim 15, wherein said first switching portion and said second switching portion are rotatable only in predetermined directions.

18. An apparatus according to claim 16, wherein said first cam portion and said second cam portion are integral with each other, and said third cam portion and said fourth cam portion are integral with each other.

19. An apparatus according to claim 15, wherein the predetermined angle is 90°

.

20. An apparatus according to claim 15, wherein the predetermined angle is 120°

.

21. An apparatus according to claim 15, wherein said driving source includes one motor capable of transmitting the driving force to said plurality of process cartridges.

22. An apparatus according to claim 15, wherein said driving source includes motors for supplying the driving force to said process cartridges, respectively.