Patent ID: 7174237

Claim:
An endless-moving-member driving unit that includes an endless moving-member including portions to be detected that are formed at a predetermined interval and a detecting unit that detects the portions to be detected and outputs a result of detection as a binary signal, the endless-moving-member driving unit changing a control of any of a speed and a position of the endless moving-member to a different control from a normal control when the portions to be detected are not detected at the predetermined interval, based on a change in the binary signal, comprising: a counter that counts a wave number of the binary signal; a storage unit that stores the wave number of the binary signal that is output when portions to be detected are detected; a calculating unit that calculates a difference between the wave number stored in the storage unit and the wave number counted by the counter in a predetermined time arbitrarily set; and a warning display unit that displays a warning that indicates a state in which the different control from the normal control is executed when the difference between the wave numbers calculated exceeds a predetermined value.