MATERIAL CONVEYOR, TRANSFER DEVICE INCORPORATING THE MATERIAL CONVEYOR, IMAGE FORMING APPARATUS INCORPORATING THE TRANSFER DEVICE, METHOD OF POSITION CONTROL OF ROTARY BODY, AND NON-TRANSITORY COMPUTER READABLE STORAGE MEDIUM

A material conveyor (80, 80A, 280, 380), of a transfer device (80, 80A, 280, 380) of an image forming apparatus (90, 200, 300), includes a first rotary body (20, 30A, 210, 320) and a second rotary body (20A, 30, 230, 330) opposing each other, and a contact and separation device (60, 60A, 260, 360) causes at least a surface, of at least one of the first rotary body (20, 30A, 210, 320) and the second rotary body (20A, 30, 230, 330) to move, between a separated position and a contact position. The contact and separation device (60, 60A, 260, 360) causes the at least the surface to move at a first speed, then at a second speed slower than the first speed. A method of position control of rotary bodies includes moving at least the surface at different speeds or based on a distance relative to a threshold distance.