An image forming apparatus includes a drive unit including a first drive train through which a driving force from the drive source is transmitted to the discharge roller and a second drive train through which a driving force from the drive source is transmitted to the reverse roller, and a switching mechanism, provided on the second drive train, configured to switch a rotating direction of the reverse roller between the forward rotating direction and the reverse rotating direction with the discharge roller rotating in one direction.

A drive transmission unit includes a cam member, a motor, a cam follower, and an extension spring. The cam member rotates about a rotation shaft. The cam member includes a first cam defining a maximum distance between the cam follower and the rotation shaft and a second cam having an outer peripheral surface positioned closer to the rotation shaft than the outer peripheral surface of the first cam. The motor rotates the rotation shaft. The cam follower is to be in contact with the cam member and moves in the +B direction and the B direction by the rotation of the cam member. The extension spring presses the cam follower against the cam member. When the cam follower moves in the B direction by the rotation of the cam member, this operation includes contact between the outer peripheral surface of the second cam and the cam follower.

The conveyance apparatus includes a first engaging portion of a first planetary gear unit and a second engaging portion of a second planetary gear unit, and a stopping member movable to a first stop position to stop a first engaged gear, and to a second stop position to stop a second engagement gear, in which a pivot fulcrum of the stopping member is arranged at an intersection between an extension line of a vector of a force that the first engaging portion receives from the first engaged portion under a state in which the stopping member is at the first stop position, and an extension line of a vector of a force that the second engaging portion receives from the second engaged portion under a state in which the stopping member is at the second stop position.

An image forming apparatus includes a support portion configured to support a sheet, a roller configured to feed the sheet supported on the support portion, a separation member configured to apply a feeding resistance to the sheet fed by the roller from the support portion, a holder holding the roller, a holder pivoting member configured to pivot the holder between a first position where the roller contacts the sheet and a second position where the roller is separated from the sheet, a clutch mechanism, a clutch-state changing member, a rotator configured to rotate between an off position where the holder is at the second position and the clutch mechanism is at a cut-off state and an on position where the holder is at the first position and the clutch mechanism is at a transmission state, a stopper configured to stop the rotator, and an actuator connected to the stopper.

An assembly method for a planetary roller speed changer is provided. The planetary roller speed changer includes a plurality of planetary rollers that is in rolling contact with both an input shaft and a fixed ring and an output shaft supported by a housing and rotating along with the planetary rollers. An assembly apparatus includes an adjustment apparatus that enables positions of the fixed ring and the housing to be adjusted and a measurement apparatus that measures irregularity of rotation of the output shaft. In an assembly step, the fixed ring and the housing are fixed at a position where the irregularity of rotation of the output shaft is minimized.

A conveyor includes: a first power transmitting mechanism configured to transmit one of forward rotation and reverse rotation of a motor to a first roller and not to transmit the other from a driven member to the first roller; and a second power transmitting mechanism configured to transmit the other rotation to the first roller and not to transmit the one rotation to the first roller. The first power transmitting mechanism includes a transmission delayer that does not transmit rotation of the motor from the driven member to the first roller until the motor is rotated by a particular amount from a time point at which the motor starts to be rotated in a rotational direction of the one rotation when rotation transmitted from the motor to the driven member is changed from the other rotation to the one rotation.

A sheet transport device includes a feeding unit that feeds out a sheet from a sheet stack unit, a driving shaft that rotates the feeding unit, plural bearing members that support the driving shaft rotatably at plural positions in an axial direction and restrict movement of the driving shaft in the axial direction, and a fixing member provided integrally with each of the bearing members to removably fix each of the bearing members to an opening and closing member that is opened and closed relative to the sheet stack unit.

Provided are a drive switching mechanism and an image printing apparatus that can downsize the apparatus. To this end, a configuration in which orbiting movement of a planetary gear is not restricted in a region other than a region from a first position to a second position during a drive switching operation is applied.

A sheet conveying device includes: a sheet discharge roller disposed in a conveying path of sheets so as to discharge a sheet being conveyed to a sheet discharge tray; a conveying unit that conveys sheets on a side of the conveying path closer to an upstream side than the sheet discharge roller; a motor that rotates at a constant system speed during conveying of sheets to drive the conveying unit; a transmission mechanism that transmits power of the motor to the sheet discharge roller to rotate the sheet discharge roller; and a controller that controls an operation of the transmission mechanism, wherein the transmission mechanism changes a circumferential speed of the sheet discharge roller, and the controller performs speed reduction control of controlling the operation of the transmission mechanism to temporarily reduce the circumferential speed of the sheet discharge roller when a sheet is discharged to the sheet discharge tray.

An image forming apparatus includes a support portion configured to support a sheet, a roller configured to feed the sheet supported on the support portion, a separation member configured to apply a feeding resistance to the sheet fed by the roller from the support portion, a holder holding the roller, a holder pivoting member configured to pivot the holder between a first position where the roller contacts the sheet and a second position where the roller is separated from the sheet, a clutch mechanism, a clutch-state changing member, a rotator configured to rotate between an off position where the holder is at the second position and the clutch mechanism is at a cut-off state and an on position where the holder is at the first position and the clutch mechanism is at a transmission state, a stopper configured to stop the rotator, and an actuator connected to the stopper.