A medium processing apparatus includes a liquid applier to apply liquid to a part of a medium to perform a liquid application, a medium processing device to perform desired processing on a bundle of media including the medium subjected to the liquid application, a liquid storage to store liquid used for the liquid application by the liquid applier, a liquid detector to detect an amount of liquid in the liquid storage, and circuitry to control a supply operation of supplying the liquid to the liquid applier to set a liquid applicable state in which the liquid applier can apply the liquid to the at least one medium based on information from the liquid detector. The circuitry changes a transition time to the liquid applicable state, based on the amount of liquid in the liquid storage detected by the liquid detector.

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.