Abstract: An image forming apparatus includes an apparatus body including a drive source, a rotary member, and a first coupling movable in an axial direction with respect to the rotary member, and a unit attachable to and detachable from the apparatus body, the unit including a second coupling configured to receive the driving force by engaging with the first coupling. The rotary member includes an abutting portion. The first coupling includes an abutted portion configured to be abutted with the abutting portion, and is configured to rotate in the first rotation direction together with the rotary member in a case where the abutting portion presses the abutted portion. The apparatus body further includes a first urging member configured to urge the first coupling in a second rotation direction opposite to the first rotation direction.

Abstract: An image forming apparatus includes an intermediate transfer member, first and second transfer members, and a control unit. The control unit includes a first state where both the first and second transfer members are separated from the intermediate transfer member, a second state where the first transfer member contacts the intermediate transfer member and the second transfer member is separated from the intermediate transfer member, and a third state where both the first and second transfer members contact the intermediate transfer member. The control unit controls the driving member to move the moving unit, controls switch the first state to the second state and thereafter switch the second state to the third state. A rotation speed of the driving member when the second state is switched to the third state is lower than a rotation speed of the driving member when the first state is switched to the second state.

Abstract: A driving force transmission device includes a drive gear, a driven gear, which includes a gear portion and a partially toothless gear portion, rotates by the gear portion meshing with the drive gear, stops rotating in response to the partially toothless gear portion facing the drive gear, a first cam member and a second cam member which operate in conjunction with the driven gear, a first elastic member for urging the first cam member, a follower member to which urging force is applied by a second elastic member and which is moved by the second cam member, and a contact portion for coming into contact with the first cam member by urging force of the first elastic member. The first cam member includes a home cam surface for coming into contact with the contact portion so that rotation of the driven gear is limited.

Abstract: An image forming apparatus includes an intermediate transfer member, first and second transfer members, and a control unit. The control unit includes a first state where both the first and second transfer members are separated from the intermediate transfer member, a second state where the first transfer member contacts the intermediate transfer member and the second transfer member is separated from the intermediate transfer member, and a third state where both the first and second transfer members contact the intermediate transfer member. The control unit controls the driving member to move the moving unit, controls switch the first state to the second state and thereafter switch the second state to the third state. A rotation speed of the driving member when the second state is switched to the third state is lower than a rotation speed of the driving member when the first state is switched to the second state.

Abstract: A driving force transmission device includes a drive gear, a driven gear, which includes a gear portion and a partially toothless gear portion, rotates by the gear portion meshing with the drive gear, stops rotating in response to the partially toothless gear portion facing the drive gear, a first cam member and a second cam member which operate in conjunction with the driven gear, a first elastic member for urging the first cam member, a follower member to which urging force is applied by a second elastic member and which is moved by the second cam member, and a contact portion for coming into contact with the first cam member by urging force of the first elastic member. The first cam member includes a home cam surface for coming into contact with the contact portion so that rotation of the driven gear is limited.

Abstract: A drive transmission device includes a driving gear, a follower gear, an intermediary gear, an output gear, and an elastic member. Transmission of a driving force from the driving gear to the follower gear and transmission of the driving force from the intermediary gear to the output gear are disabled, in a non-transmission state. In a transmission state, (i) the follower gear is moved by an elastic force of the elastic member to enable rotation of the follower gear by the driving force from the driving gear, and thereafter, (ii) the intermediary gear is rotated by the follower gear without rotating the output gear, and thereafter, the intermediary gear is enabled to transmit the driving force to the output gear.

Abstract: A developing cartridge mountable to a development rotary of an electrophotographic image forming apparatus, a coupling member for transmitting a rotational force from a main assembly engaging portion to a developing roller, the coupling member being engageable and disengageable relative to the engaging portion with rotation of the rotary, the coupling member being movable among a rotational force transmitting angular position, a pre-engagement angular position in which the coupling member is inclined relative to that in the transmitting angular position to engage with the engaging portion, and a disengaging angular position for disengaging therefrom; and an inclination regulating member movable between a regulating position for positioning the coupling member to the pre-engagement position and a retracted position, the inclination regulating member being movable from the retracted position to the regulating position by being abutted by a function member of the rotary.

Abstract: A developing cartridge mountable to a development rotary of an electrophotographic image forming apparatus, a coupling member for transmitting a rotational force from a main assembly engaging portion to a developing roller, the coupling member being engageable and disengageable relative to the engaging portion with rotation of the rotary, the coupling member being movable among a rotational force transmitting angular position, a pre-engagement angular position in which the coupling member is inclined relative to that in the transmitting angular position to engage with the engaging portion, and a disengaging angular position for disengaging therefrom; and an inclination regulating member movable between a regulating position for positioning the coupling member to the pre-engagement position and a retracted position, the inclination regulating member being movable from the retracted position to the regulating position by being abutted by a function member of the rotary.

Abstract: A drive transmission device includes a rotatable driving member; a rotatable follower member, and an elastic member. The drive transmission device includes a first rotatable member and a second rotatable member. The first rotatable member includes first and second driving portions and a limiting portion. The second rotatable member includes a first driven portion, a second driven portion and a contact portion contacting the limiting portion. The second driving portion is adjacent to the limiting portion with respect to a rotational axis direction of the first rotatable member. The second driven portion is adjacent to the contact portion with respect to a rotational direction of the second rotatable member.

Abstract: A drive transmission device includes a driving gear, a follower gear, an intermediary gear, an output gear, and an elastic member. Transmission of a driving force from the driving gear to the follower gear and transmission of the driving force from the intermediary gear to the output gear are disabled, in a non-transmission state. In a transmission state, (i) the follower gear is moved by an elastic force of the elastic member to enable rotation of the follower gear by the driving force from the driving gear, and thereafter, (ii) the intermediary gear is rotated by the follower gear without rotating the output gear, and thereafter, the intermediary gear is enabled to transmit the driving force to the output gear.

Abstract: An elastic force of an elastic member 11 required for rotating a driven rotational body 8b is decreased. A first rotational body 8d and a second rotational body 9a arranged downstream of a driven rotational body 8b in a drive train that transmits a driving force from a driving rotational body 7 to a driven member 4 are included. The first rotational body 8d rotates in synchronization with the driven rotational body 8b. The second rotational body 9a is rotated by the first rotational body 8d and rotates the driven member 4. The first rotational body 8d rotates without rotating the second rotational body 9a when the driven rotational body 8b rotates by an elastic force of an elastic member 11.

Abstract: A developing cartridge mountable to a development rotary of an electrophotographic image forming apparatus, a coupling member for transmitting a rotational force from a main assembly engaging portion to a developing roller, the coupling member being engageable and disengageable relative to the engaging portion with rotation of the rotary, the coupling member being movable among a rotational force transmitting angular position, a pre-engagement angular position in which the coupling member is inclined relative to that in the transmitting angular position to engage with the engaging portion, and a disengaging angular position for disengaging therefrom; and an inclination regulating member movable between a regulating position for positioning the coupling member to the pre-engagement position and a retracted position, the inclination regulating member being movable from the retracted position to the regulating position by being abutted by a function member of the rotary.

Abstract: A clutch includes a rotatable inputting member, a rotatable outputting member, a stationary member, and a contact member. The outputting member includes an output contact portion. The contact member is positioned between the outputting member and the stationary member and includes an arcuate first contact surface and a second contact surface. When the input torque for rotating the inputting member is inputted, the outputting member and the contact member rotate in contact with the inputting member. When a reverse input torque for rotating the outputting member is inputted, the outputting member is spaced from the inputting member, and the output contact portion of the outputting member urges the first contact surface against the stationary member by urging the second contact surface of the contact member thereby to prevent rotation of the outputting member.

Abstract: A developing cartridge mountable to a development rotary of an electrophotographic image forming apparatus, a coupling member for transmitting a rotational force from a main assembly engaging portion to a developing roller, the coupling member being engageable and disengageable relative to the engaging portion with rotation of the rotary, the coupling member being movable among a rotational force transmitting angular positio, a pre-engagement angular position in which the coupling member is inclined relative to that in the transmitting angular position to engage with the engaging portion, and a disengaging angular position for disengaging therefrom; and an inclination regulating member movable between a regulating position for positioning the coupling member to the pre-engagement position and a retracted position, the inclination regulating member being movable from the retracted position to the regulating position by being abutted by a function member of the rotary.

Abstract: A drive transmission apparatus includes a first rotating unit rotated by driving force from a drive source and a second rotating unit rotated by the first rotating unit. The first and second rotating units include a first gear pair meshing at a first transmission ratio and second gear pair meshing at a second transmission ratio. A retention mechanism includes a protruded portion provided on the first rotating unit and a recessed portion provided on the second rotating unit, and is configured to retain a rotation angle of the second rotating unit by an engagement of the protruded portion and the recessed portion in a state where the first and second gear pairs are unmeshed.

Abstract: An elastic force of an elastic member 11 required for rotating a driven rotational body 8b is decreased. A first rotational body 8d and a second rotational body 9a arranged downstream of a driven rotational body 8b in a drive train that transmits a driving force from a driving rotational body 7 to a driven member 4 are included. The first rotational body 8d rotates in synchronization with the driven rotational body 8b. The second rotational body 9a is rotated by the first rotational body 8d and rotates the driven member 4. The first rotational body 8d rotates without rotating the second rotational body 9a when the driven rotational body 8b rotates by an elastic force of an elastic member 11.

Abstract: An elastic force of an elastic member 11 required for rotating a driven rotational body 8b is decreased. A first rotational body 8d and a second rotational body 9a arranged downstream of a driven rotational body 8b in a drive train that transmits a driving force from a driving rotational body 7 to a driven member 4 are included. The first rotational body 8d rotates in synchronization with the driven rotational body 8b. The second rotational body 9a is rotated by the first rotational body 8d and rotates the driven member 4. The first rotational body 8d rotates without rotating the second rotational body 9a when the driven rotational body 8b rotates by an elastic force of an elastic member 11.

Abstract: A developing cartridge mountable to a development rotary of an electrophotographic image forming apparatus, a coupling member for transmitting a rotational force from a main assembly engaging portion to a developing roller, the coupling member being engageable and disengageable relative to the engaging portion with rotation of the rotary, the coupling member being movable among a rotational force transmitting angular positio, a pre-engagement angular position in which the coupling member is inclined relative to that in the transmitting angular position to engage with the engaging portion, and a disengaging angular position for disengaging therefrom; and an inclination regulating member movable between a regulating position for positioning the coupling member to the pre-engagement position and a retracted position, the inclination regulating member being movable from the retracted position to the regulating position by being abutted by a function member of the rotary.

Abstract: A clutch includes a rotatable inputting member, a rotatable outputting member, a stationary member, and a contact member. The outputting member includes an output contact portion. The contact member is positioned between the outputting member and the stationary member and includes an arcuate first contact surface and a second contact surface. When the input torque for rotating the inputting member is inputted, the outputting member and the contact member rotate in contact with the inputting member. When a reverse input torque for rotating the outputting member is inputted, the outputting member is spaced from the inputting member, and the output contact portion of the outputting member urges the first contact surface against the stationary member by urging the second contact surface of the contact member thereby to prevent rotation of the outputting member.

Abstract: A drive transmission apparatus includes a first rotating unit rotated by driving force from a drive source and a second rotating unit rotated by the first rotating unit. The first and second rotating units includes first gear pair meshing at a first transmission ratio and second gear pair meshing at a second transmission ratio. A retention mechanism includes a protruded portion provided on the first rotating unit and a recessed portion provided on the second rotating unit, and is configured to retain a rotation angle of the second rotating unit by an engagement of the protruded portion and the recessed portion in a state where the first and second gear pairs are unmeshed.