Image forming apparatus and storage medium

A non-transitory computer-readable storage medium storing a program that controls a computer of an image forming apparatus including, a medium oscillating mechanism that oscillates a recording medium along a medium width direction intersecting a conveyance direction of the recording medium, a medium sensing section that senses a position of an end of the recording medium in the medium width direction, a belt correction mechanism that is configured to correct a position of a belt in the medium width direction, the belt executing one of processes of the image formation on the recording medium, and a belt sensing section that senses the position of the end of the belt in the medium width direction, the program causing the computer to execute the following:

• performing first rectification control in which the medium oscillating mechanism rectifies the position of the end of the recording medium based on sensing by the medium sensing section,
• performing second rectification control in which the belt correction mechanism rectifies the position of the end of the belt based on sensing by the belt sensing section, and
• performing a correction to the second rectification control in a case in which the first rectification control is performed with the recording medium straddling both the medium oscillating mechanism and the belt.