Medium processing apparatus, image forming system, medium processing method, and non-transitory recording medium

A medium processing apparatus comprising:

• a conveyor including a conveyance roller configured to convey a sheet-shaped medium in a conveyance direction;
• a tray configured to hold the medium conveyed by the conveyor;
• a conveyance-direction fence configured to contact a downstream end, in the conveyance direction, of the medium placed on the tray and aligns a position, in the conveyance direction, of the medium;
• a crimp binder disposed to face the downstream end, in the conveyance direction, of the medium placed on the tray to press and deform a binding position on a plurality of media, including the medium, of which the position in the conveyance direction is aligned by the conveyance-direction fence, to bind the plurality of media;
• a pair of width-direction fences configured to contact opposed ends, in a main scanning direction, of the plurality of media and move in the main scanning direction to align a position, in the main scanning direction, of the plurality of media, the main scanning direction being orthogonal to each of the conveyance direction and a thickness direction of the medium placed on the tray;
• and
• circuitry configured to control operations of the conveyor, the conveyance-direction fence, and the crimp binder,
• the conveyance-direction fence and the crimp binder being movable in the main scanning direction,
• the circuitry being configured to:
• determine whether the conveyance-direction fence overlaps the binding position when the tray is viewed in the thickness direction;
• move the conveyance-direction fence in the main scanning direction to a position away from the binding position while the plurality of media is fixed to the tray, in a case where the circuitry determines that the conveyance-direction fence overlaps the binding position when the tray is viewed in the thickness direction;
• and
• cause the crimp binder to crimp and bind the plurality of media, and
• the circuitry being further configured to move the conveyance-direction fence in the main scanning direction while the opposed ends of the plurality of media contact the pair of width-direction fences.