SHEET CONVEYANCE APPARATUS, IMAGE FORMING APPARATUS, AND METHOD FOR ESTIMATING DURATION OF A ROTARY MEMBER

The present invention relates to a sheet conveyance apparatus comprising a rotary member for conveying a sheet; a controller for detecting lowered conveyance performance due to wear of the rotary member, for measuring operation time of the rotary member, for memorizing in advance a limit wearing degree immediately before the rotary member becomes unable to make conveyance due to wear, and for estimating a time at which the rotary member becomes unable to make conveyance due to wear. The duration estimating means uses the wearing degree of the rotary member, the operation time of the rotary member, and the limit wearing degree, to calculate according to an estimation function the time ending the duration at which the rotary member becomes unable to make conveyance due to wear.