Process cartridge and image forming apparatus

1. A cartridge comprising:

a developing roller;

a downstream side drive transmission member rotatable about an axis thereof and movable along the axis between a transmission position in which in the downstream side drive transmission member is capable of transmitting a driving force toward the developing roller and a blocked position in which transmission of the driving force to the developing roller is blocked;

an upstream side drive transmission member capable of transmitting the driving force toward the downstream side drive transmission member;

an elastic member for urging the downstream side drive transmission member toward the blocked position from the transmission position; and

a maintaining member movable between a maintaining position for maintaining the downstream side drive transmission member in the transmission position against an elastic force of the elastic member and a permitting position for permitting the downstream side drive transmission member to move to the blocked position by the elastic force of the elastic member,

wherein the downstream side drive transmission member is coupled to the upstream side transmission member when the downstream side drive transmission member is in the transmission position, and the downstream side drive transmission member is not coupled to the upstream side transmission member when the downstream side drive transmission member is in the blocked position.

2. A cartridge according to claim 1 , further comprising an intervening member sandwiched between the elastic member and the downstream side drive transmission member, the intervening member being rotatable relative to the downstream side drive transmission member.

3. A cartridge according to claim 1 , wherein an area in which the intervening member is in contact with the downstream side drive transmission member is larger than an area in which the elastic member is in contact with the intervening member.

4. A cartridge according to claim 1 , further comprising a supporting member rotatably supporting the developing roller, and

wherein the maintaining member is rotatable relative to the supporting member.

5. A cartridge according to claim 1 , wherein the downstream side drive transmission member, the upstream side drive transmission member, the elastic member, and the maintaining member are arranged along the axis of the downstream side drive transmission member.

6. A cartridge according to claim 1 , further comprising an intervening member sandwiched between the elastic member and the upstream side drive transmission member, the intervening member being rotatable relative to the upstream side drive transmission member.

7. A cartridge according to claim 6 , wherein an area in which the intervening member is in contact with the upstream side drive transmission member is larger than an area in which the elastic member is in contact with the intervening member.

8. A cartridge according to claim 1 , further comprising a cam portion for moving the maintaining member from the permitting position to the maintaining position.

9. A cartridge comprising:

a developing roller;

a downstream side drive transmission member configured to receive a driving force and transmit the driving force toward the developing roller;

an upstream side drive transmission member rotatable about an axis thereof and movable along the axis between a transmission position in which the upstream side drive transmission member is capable of transmitting the driving force toward the downstream side drive transmission member and a blocked position in which the transmission of the driving force to the downstream side drive transmission member is blocked;

an elastic member for urging the upstream side drive transmission member toward the blocked position from the transmission position; and

a maintaining member movable between a maintaining position for maintaining the upstream side drive transmission member in the transmission position against an elastic force of the elastic member and a permitting position for permitting the upstream side drive transmission member to move to the blocked position by the elastic force of the elastic member,

wherein the upstream side drive transmission member is coupled to the downstream side transmission member when the upstream side drive transmission member is in the transmission position, and the upstream side drive transmission member is not coupled to the downstream side transmission member when the upstream side drive transmission member is in the blocked position.

10. A cartridge according to claim 9 , further comprising an intervening member sandwiched between the elastic member and the upstream side drive transmission member, the intervening member being rotatable relative to the upstream side drive transmission member.

11. A cartridge according to claim 10 , wherein an area in which the intervening member is in contact with the upstream side drive transmission member is larger than an area in which the elastic member is in contact with the intervening member.

12. A cartridge according to claim 9 , further comprising a supporting member rotatably supporting the developing roller,

wherein the maintaining member is rotatable relative to the supporting member.

13. A cartridge according to claim 9 , wherein the downstream side drive transmission member, the upstream side drive transmission member, the elastic member, and the maintaining member are arranged along the axis of the upstream side drive transmission member.

14. A cartridge according to claim 9 , further comprising an intervening member sandwiched between the elastic member and the downstream side drive transmission member, the intervening member being rotatable relative to the downstream side drive transmission member.

15. A cartridge according to claim 14 , wherein an area in which the intervening member is in contact with the downstream side drive transmission member is larger than an area in which the elastic member is in contact with the intervening member.

16. A cartridge according to claim 9 , further comprising a cam portion for moving the maintaining member from the permitting position to the maintaining position.