Printing apparatus and printing method

A printing apparatus, comprising:

• a transport mechanism that transports, along a transport path, sheets of a print medium with a first surface on which a first mark is pre-printed;
• a first sensor disposed to face the transport path, the first sensor outputting a signal indicating the presence or absence of the first mark facing the first sensor, in a process of transporting the print medium by the transport mechanism;
• a first determining unit that locates a position of the first mark based on the signal output from the first sensor, and determines, on the first surface, a print position of a second mark and a print position of a first target image based on the located position of the first mark;
• a first print head disposed more downstream of the transport path than the first sensor to face the first surface, the first print head printing the second mark at the print position of the second mark and the first target image at the print position of the first target image, the print positions being determined on the first surface by the first determining unit;
• a second sensor disposed more downstream of the transport path than the first print head to face the first surface, the second sensor outputting a signal indicating the presence or absence of the first mark facing the second sensor and the presence or absence of the second mark facing the second sensor, in the process of transporting the print medium by the transport mechanism;
• a second determining unit that locates a position of a predetermined one of the first mark and the second mark, based on the signal output from the second sensor, and determines, on a second surface of the print medium, a print position of a second target image based on the located position of the predetermined one of the first mark and the second mark;
• and
• a second print head disposed more downstream of the transport path than the second sensor to face the second surface, the second print head printing the second target image at the print position of the second target image, the print position being determined on the second surface by the second determining unit.