Patent ID: 8079590

Claim:
An image forming apparatus comprising: a pair of conveyance rollers to nip and convey a sheet; a turning amount detection section which includes a bearing section coming in contact with the sheet downstream of the pair of conveyance rollers, a distance from a center point of a contact portion of the pair of conveyance rollers to a point where a bearing section contact the sheet is 3 mm or less; a thickness detection section to detect a thickness of the sheet based on a turning amount detected by the turning amount detection section; a pair of register rollers which is disposed downstream of the bearing section and aligns the sheet; and an image recording section to record the image on the sheet passing through the pair of register rollers, wherein the turning amount detection section includes: the bearing section including a shaft, an inner ring fitted to the shaft, an outer ring disposed coaxially with the inner ring, and a plurality of ball bearings provided between the outer ring and the inner ring; an arm section turned by the thickness of the sheet brought into contact with the bearing section; and an electric turning amount detection section to electrically detect the turning amount of the arm section.