Image forming apparatus and length measuring device

An image forming apparatus comprising:

• an image forming unit that forms an image on a recording sheet;
• a transport unit that transports the recording sheet on which the image is formed by the image forming unit;
• a support surface that supports the recording sheet transported by the transport unit;
• a rotating member that has an outer peripheral surface moved toward the support surface when the recording sheet passes through between the support surface and the outer peripheral surface and that rotationally follows the recording sheet when the recording sheet passes through between the support surface and the outer peripheral surface;
• an ascertaining unit that ascertains a length of the recording sheet on the basis of an amount of rotation of the rotating member;
• and
• a restricting unit that restricts a movement of the rotating member that moves toward the support surface, and moves the rotating member away from the support surface after the recording sheet passes through between the support surface and the outer peripheral surface of the rotating member.