Inkjet recording apparatus

An inkjet recording apparatus, comprising:

• a paper conveyance mechanism configured to convey plural sheets of paper;
• a recording head configured to form, by using ink, an image on each of the sheets of paper being conveyed based on image data;
• and
• a controller configured to control respective operations of the paper conveyance mechanism and the recording head, wherein
• the sheets of paper include a first sheet of paper and a second sheet of paper,
• the first sheet of paper has a first side and a second side being a back side of the first side,
• the second sheet of paper has a third side and a fourth side being a back side of the third side,
• the image data contains first image data representing a first image and second image data representing a second image,
• the recording head forms the first image and a first mark image on the first side based on the first image data, and then forms the second image and a second mark image on the second side based on the second image data,
• the first mark image represents a first reference location in a first rectangular region in which the first image is to be formed,
• the second mark image represents a second reference location in a second rectangular region in which the second image is to be formed, and
• the controller determines an enlargement ratio of the second image to be formed on the fourth side based on a discrepancy between the first reference location and the second reference location.