Image forming apparatus for improving accuracy in alignment of an image to be printed on two surfaces of a recording medium by measuring a size of the recording medium

An image forming apparatus comprising:

• an image forming unit configured to form an image on a recording medium;
• an inverting transport unit configured to invert a first surface and a second surface of the recording medium on which the image is formed by the image forming unit, and a front end and a rear end of the recording medium to transport the inverted recording medium;
• a recording medium width measuring unit configured to measure an end position of the recording medium in a width direction orthogonal to a transporting direction of the recording medium before and after the image is formed on the recording medium by the image forming unit;
• and
• a recording medium length measuring unit configured to measure a length of the recording medium in the transporting direction of the recording medium;
• a correcting unit configured to correct a size of an image to be formed on a subsequent recording medium by the image forming unit based on a change in a shape of the recording medium computed based on a measured result obtained by the recording medium width measuring unit and a measured result obtained by the recording medium length measuring unit;
• and
• a resist unit disposed upstream of the recording medium width measuring unit and the recording medium length measuring unit in the transporting path of the recording medium, and configured to correct a transporting direction of the recording medium and transport the corrected recording medium at a time at which the image forming unit forms the image on the recording medium,
• wherein the recording medium width measuring unit measures the end position of the recording medium in the width direction at a measuring position having an approximately identical distance from one end of the recording medium in the transporting direction of the recording medium before and after the image is formed on the recording medium by the image forming unit,
• wherein the recording medium length measuring unit includes a recording medium transport unit configured to transport the recording medium, and
• wherein the recording medium length measuring unit configured to measure the length in the transporting direction of the recording medium, the recording medium width measuring unit, and the resist unit are arranged in this order from the downstream of the sheet transporting direction.