An image forming apparatus includes: a conveyance section configured to convey a sheet in a direction opposite to a first conveyance direction during image formation, the direction being a second conveyance direction; and a distortion correction section disposed on an upstream side of a transfer nip in the first conveyance direction and configured to correct, when the sheet is conveyed by the conveyance section in the second conveyance direction, distortion of the sheet generated when the sheet passes through a fixing nip.

A sheet humidification apparatus includes a detect sensor that detects a position of a sheet which is being conveyed; a humidifier that changes a humidification amount and humidifies the sheet; and a controller that controls the humidifier such that a first region on a front end side of the sheet in a conveyance direction is humidified with a first humidification amount, and a second region of the sheet other than the first region is humidified with a second humidification amount larger than the first humidification amount in accordance with a position of the sheet detected by the detect sensor.

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.