An image forming apparatus comprises a transfer section, a fixing section, and a controller. The transfer section includes a transfer rotating body for conveying a sheet at a first linear velocity, and transfers a toner image onto the sheet. The fixing section forms a nip sandwiching the sheet with a first rotating body and a second rotating body, and a heating section for heating the sheet onto which the toner image is transferred. The controller executes a sheet acceleration and deceleration control for setting a linear velocity of the first rotating body to a second linear velocity from the first linear velocity before the tip of the sheet reaches the nip, and decelerating the linear velocity of the first rotating body from the second linear velocity to the first linear velocity at the time the tip of the sheet reaches a predetermined range in a sheet conveyance path.

An image forming apparatus comprises a transfer section, a fixing section, and a controller. The transfer section includes a transfer rotating body for conveying a sheet at a first linear velocity, and transfers a toner image onto the sheet. The fixing section forms a nip sandwiching the sheet with a first rotating body and a second rotating body, and a heating section for heating the sheet onto which the toner image is transferred. The controller executes a sheet acceleration and deceleration control for setting a linear velocity of the first rotating body to a second linear velocity from the first linear velocity before the tip of the sheet reaches the nip, and decelerating the linear velocity of the first rotating body from the second linear velocity to the first linear velocity at the time the tip of the sheet reaches a predetermined range in a sheet conveyance path.

A conveyor comprises a first conveyor roller unit and a side position adjustment mechanism. The side position adjustment mechanism includes a guide member and a position adjustment roller unit. The position adjustment roller unit includes a first position adjustment roller and a second position adjustment roller which holds a sheet-shaped medium with the first position adjustment roller. An angle between a rotational axial line of the first position adjustment roller and a part of a guide face of the guide member which part is on the downstream of an intersection between the rotational axial line of the first position adjustment roller and the guide face is an acute angle. The conveyor further comprises a first support member which supports a first driven roller of the first conveyor roller unit to allow a rotational axial line of the first driven roller to be swingable.

A conveyor comprises a first conveyor roller unit and a side position adjustment mechanism. The side position adjustment mechanism includes a guide member and a position adjustment roller unit. The position adjustment roller unit includes a first position adjustment roller and a second position adjustment roller which holds a sheet-shaped medium with the first position adjustment roller. An angle between a rotational axial line of the first position adjustment roller and a part of a guide face of the guide member which part is on the downstream of an intersection between the rotational axial line of the first position adjustment roller and the guide face is an acute angle. The conveyor further comprises a first support member which supports a first driven roller of the first conveyor roller unit to allow a rotational axial line of the first driven roller to be swingable.

A medium processing device includes a plurality of crimping teeth and circuitry. The plurality of crimping teeth presses and deforms a position on a sheet bundle to bind the sheet bundle. The sheet bundle is a bundle of stacked sheet-shaped media. The plurality of crimping teeth flattens the position pressed and deformed to unbind the sheet bundle. The circuitry causes the plurality of crimping teeth to sandwich the position on the sheet bundle.

A medium processing device includes a plurality of crimping teeth and circuitry. The plurality of crimping teeth presses and deforms a position on a sheet bundle to bind the sheet bundle. The sheet bundle is a bundle of stacked sheet-shaped media. The plurality of crimping teeth flattens the position pressed and deformed to unbind the sheet bundle. The circuitry causes the plurality of crimping teeth to sandwich the position on the sheet bundle.

A sheet processing apparatus includes a binding portion binding a plurality of sheets stacked on a sheet stacking portion as a bundle by deforming the sheets without a staple. The sheet processing apparatus further includes a moving member moving the sheet bundle bound at a binding position by the binding portion from the binding position and a restricting member restricting the move of the sheet bundle such that a distance between the sheet bundle and the moving member is kept to be less than a predetermined distance in moving the sheet bundle by the moving member.

A sheet processing apparatus includes a binding portion binding a plurality of sheets stacked on a sheet stacking portion as a bundle by deforming the sheets without a staple. The sheet processing apparatus further includes a moving member moving the sheet bundle bound at a binding position by the binding portion from the binding position and a restricting member restricting the move of the sheet bundle such that a distance between the sheet bundle and the moving member is kept to be less than a predetermined distance in moving the sheet bundle by the moving member.

A sheet processing apparatus includes a conveying portion, a stack portion which stacks sheets, a first regulating portion which regulates a position of a sheet bundle in a crossing direction crossing to a conveying direction, a second regulating portion which regulates a position of a sheet bundle in the conveying direction, a first binding portion which moves from a first side to a second side and binds a corner portion of a sheet bundle by a staple, a second binding portion which binds a corner portion of a sheet bundle without a staple. The second binding portion includes a first face having a plurality of projections and a second face having a plurality of concave grooves matching the plurality of projections. A sheet bundle is bound by pressing the first face and the second face.

A sheet processing apparatus includes a conveying portion, a stack portion which stacks sheets, a first regulating portion which regulates a position of a sheet bundle in a crossing direction crossing to a conveying direction, a second regulating portion which regulates a position of a sheet bundle in the conveying direction, a first binding portion which moves from a first side to a second side and binds a corner portion of a sheet bundle by a staple, a second binding portion which binds a corner portion of a sheet bundle without a staple. The second binding portion includes a first face having a plurality of projections and a second face having a plurality of concave grooves matching the plurality of projections. A sheet bundle is bound by pressing the first face and the second face.