Image forming apparatus and computer readable medium storing program

An image forming apparatus comprising:

• a transfer member onto a front side of which an image is transferred, the transfer member being configured to be circularly movable;
• a rotary member around which the transfer member is wrapped;
• a guide member provided at an end portion of an axial direction of the rotary member;
• a regulating member that is located on a reverse side of the transfer member in the end portion of the axial direction of the rotary member, the regulating member restricting skew of the transfer member by contacting the guide member;
• a first reference mark provided in a first position on an edge side of the transfer member in the axial direction of the rotary member;
• a second reference mark provided in a second position on another edge side of the transfer member in the axial direction of the rotary member;
• a first detector that detects the first reference mark;
• a second detector that detects the second reference mark;
• and
• a controller that controls alignment of the image on the transfer member in accordance with a detection result of the first detector and the second detector,
• wherein the first position of the first reference mark and the second position of the second reference mark are located so that when the regulating member and the guide member are in contact with each other, only one of the first detector and the second detector detects the first reference mark or the second reference mark and so that when the regulating member and the guide member are not in contact with each other, both the first detector and the second detector detect the first reference mark and the second reference mark, respectively.