A heat roller includes a main body and a follower gear. The main body includes a cutaway portion and a pair of protruding plate portions. The follower gear includes a transmission protrusion and an abutment portion. The transmission protrusion is abutted against one protruding plate portion, when the follower gear rotates. The abutment portion is abutted against the one protruding plate portion, when the main body rotates in advance. A size of the transmission protrusion along the width direction of the cutaway portion is smaller than a clearance between the pair of protruding plate portions in the width direction, and a clearance between the abutment portion and the one protruding plate portion in the roller rotation direction is narrower than a clearance between the transmission protrusion and the other protruding plate portion in the roller rotation direction, when the transmission protrusion is in contact with the one protruding plate portion.

An image forming apparatus according to an example includes a main body, a driving coupler to drive a toner cartridge. The driving coupler is rotatable in a direction, a locking protrusion protrudes from an axial protrusion of the driving coupler in the direction of the driving shaft is lockable into a locking groove concavely formed in the direction of the driving shaft of a passive coupler of the toner cartridge. A driving force transmission surface of the axial protrusion of the driving coupler and a driving force receiving surface of the passive coupler are to contact each other to rotate the passive coupler in the direction.

Provided is a method for removing a first holder member from a second holder member in a cartridge. The cartridge includes: a housing; the first holder member holding an electrical contact surface; and the second holder member supported by the housing. The first holder member includes a pawl, and the second holder member includes a corner part engageable with the pawl of the first holder member. The electrical contact surface is held at one end surface of the first holder member in a first direction crossing the electrical contact surface. The method includes: disengaging the pawl from the corner part; and separating the housing and the second holder member from the first holder member in the first direction away from the one end surface of the first holder member.

A drive device includes a drive source, a drive train including a plurality of drive transmitters, and a positioning member. The drive train transmits a driving force of the drive source to a driven member. The plurality of drive transmitters include a first group of the drive transmitters and a second group of the drive transmitters. The drive source and the first group of the drive transmitters together serve as an integrated unit attached to one side of a facing member facing a side panel of an image forming apparatus. The integrated unit includes a positioning object. The second group of the drive transmitters is supported by a shaft disposed on another side of the facing member. The positioning member includes a positioning portion with which the positioning object is engaged on the one side or said another side of the facing member.

An electrophotographic image forming apparatus comprises a main assembly that includes moving force applying portion, a main assembly engaging portion having a driving shaft and a rotational force applying portion provided on the driving shaft, and an electrophotographic photosensitive drum. A cartridge is dismountable from the main assembly without dismounting the electrophotographic photosensitive drum from the main assembly. The cartridge includes a developing roller for developing a latent image formed on the electrophotographic photosensitive drum, a rotatable member for transmitting a rotational force to the developing roller, and a coupling member including a rotational force receiving portion engageable with the rotational force applying portion to receive a rotational force from the main assembly engaging portion, and a rotational force transmitting portion for transmitting the rotational force to the rotatable member. The cartridge also includes a frame including a moving force receiving portion that receives a moving force from the moving force applying portion, the frame supporting the developing roller and the rotatable member.

A rotation transmission structure includes: a first member that is provided on a rotating body and includes a plural straight teeth extending in an axial direction of the rotating body and arranged in a circumferential direction; a second member that is provided on a moving body moving in the axial direction of the rotating body, includes a plural straight teeth extending in the axial direction of the rotating body and arranged in the circumferential direction, and is fitted to the first member to transmit rotation of the rotating body to the moving body in a case where the moving body approaches the rotating body; a biasing member that biases the first member toward the moving body; and a rotation mechanism that is provided between the first member and the rotating body and rotates the first member in a case where the first member is moved toward the rotating body.

A coupling member is provided for a cartridge that includes a cylindrical photosensitive drum that is rotatable about an axis. The coupling member is operatively connected to the photosensitive drum and is capable of receiving a rotational force for rotating the photosensitive drum.

A first gear is arranged at an end of a first roller and rotatable together with the first roller. A second roller nips a sheet with the first roller and conveys the sheet to a print engine. The second roller is movable to change a distance between an axis of the first roller and an axis of the second roller. A second gear is arranged at an end of the second roller and rotatable together with the second roller. An urging member urges the second roller toward the first roller. A drive gear has gear teeth. The drive gear is rotatable by receiving driving force from a motor. A first drive transmission part transmits driving force from the drive gear to the first gear not through the second gear. A second drive transmission part transmits driving force from the drive gear to the second gear not through the first gear.

A replaceable unit for an electrophotographic image forming device includes a housing having a reservoir for holding toner. An electrical connector is positioned on a first side of the housing. The electrical connector includes an electrical contact for contacting a corresponding electrical contact in the image forming device and a magnetic sensor electrically connected to the electrical contact. The electrical connector is movable between a first position and a second position. When the electrical connector moves from the first position to the second position, the electrical contact of the replaceable unit moves from a retracted position to an operative position. When the electrical connector moves from the first position to the second position, the magnetic sensor moves from a misaligned position to an aligned position with a point in a path of movement of a magnet for sensing a magnetic field of the magnet.

An image forming apparatus includes a motor, an image formation-transfer section, a switching mechanism, a fixing section, and a controller. The motor generates driving force. The image formation-transfer section state-changes between a first contact state and a first separate state by the driving force. The switching mechanism transmits and cuts off the driving force to the image formation-transfer section. The fixing section includes first and second rotating members, and state-changes between a second contact state and a second separate state by the driving force. The controller controls the motor and the switching mechanism and thereby causes part or all of a first period, in which the fixing section state-changes from the second separate state to the second contact state, and part or all of a second period, in which the image formation-transfer section state-changes from the first separate state to the first contact state, to overlap each other.