An image forming system includes one or plural processors. The one or plural processors are configured to cause binding processing of binding plural sheets of paper to create a paper bundle to be performed by selected one of the binding processing of staple processing using a staple and stapleless processing without using the staple, and perform, in a case where a predetermined event occurs in creating the paper bundle, first switching processing of switching the binding processing to the other binding processing.

A post-processing apparatus includes a manual processing device, a sheet binder, a driver, and a shield. The manual processing device has an opening to receive a sheet bundle of multiple sheets inserted into the opening. The sheet binder performs a binding operation on the sheet bundle in the manual processing device at a binding position in the opening. The driver moves the sheet binder in a first direction. The shield is movable, in a second direction intersecting the first direction, between a closed position at which the shield closes the opening and an open position at which the shield opens the opening, in response to a movement of the sheet binder in the first direction.

A medium processing apparatus includes a liquid application member to contact a medium to apply liquid to the medium, a movement mechanism to move the liquid application member close to or away from the medium, and a liquid-application sensor to determine whether the liquid application member has passed through a detection area of the liquid-application sensor when the liquid application member is moved close to or away from the medium. When the liquid application member is moved close to the medium, the movement mechanism moves the liquid application member at a first speed to get close to the medium after the liquid application member has passed through the detection area, and moves the liquid application member at a second speed slower than the first speed to get close to the medium until the liquid application member passes through the detection area.

A printing system includes a printing apparatus that prints an image on a sheet, a sheet processer that executes sheet processing, and a sheet detection sensor that detects a sheet on which the sheet processing is performed not in association with the printing of an image, where the printing of an image is restricted in response to detection of a sheet by the sheet detection sensor.

A post-processing device includes a staple fastening device that fastens a medium with a staple; a stapleless fastening device that fastens a medium without using the staple; and a guiding part that guides the staple fastening device and the stapleless fastening device such that the staple fastening device and the stapleless fastening device are movable in a width direction of a medium, in which a moving speed of the stapleless fastening device is slower than a moving speed of the staple fastening device when a moving timing of the staple fastening device and a moving timing of the stapleless fastening device overlap each other.

A medium processing apparatus includes a stapling device that binds media with staples; a stapleless binding device that binds media without the staples; a guide member that guides the stapling device and the stapleless binding device in a width direction of the media; and a frame disposed at a first end portion of the guide member in the width direction, the frame being positioned inward from an outer edge of the stapleless binding device in a width direction of the stapleless binding device when the stapleless binding device is moved to the first end portion of the guide member.

A sheet processing device includes a collecting part configured to collect a plurality of sheets that are carried in; a plurality of lower-end-receiving members with which lower ends of the sheets collected to the collecting part are brought into contact, the lower ends being downstream ends in a carry-in direction; a binder configured to bind a part of an end portion of a sheet batch, the sheet batch being the plurality of sheets collected to the collecting part, the end portion including the lower ends; and a mover-supporter supporting the binder and configured to move the binder around the end portion of the sheet batch in such a manner as to stop the binder at a plurality of stop positions including a plurality of binding positions, in which one of the plurality of lower-end-receiving members is provided on a movable member that is movable in a widthwise direction that intersects the carry-in direction, in which the one lower-end-receiving member is provided with a conjugate movement mechanism configured to move the one lower-end-receiving member in conjunction with a movement of the binder, in which in response to the binder moving in a specific direction toward a predetermined binding position, the conjugate movement mechanism moves the one lower-end-receiving member in the specific direction from a normal position by a predetermined distance, in which in response to the binder moving by a distance greater than the predetermined distance, the conjugate movement mechanism returns the one lower-end-receiving member to the normal position.