Gap adjustment method of an ink jet device and an ink jet device

A gap adjustment method of an ink jet device, wherein the ink jet device includes a head unit with an ink discharge port that discharges ink, a carriage that is provided with the head unit and moves in a main scanning direction, a landing target object provided with a gap with respect to the ink discharge port, and a gap adjustment means that adjusts a length of the gap;

• wherein the gap adjustment method comprises:
• a discharging process of discharging ink from the ink discharge port while reciprocating the carriage in the main scanning direction, and landing an ink droplet to each of a forward path landing position, which is a position on the landing target object the ink droplet is to be landed in a forward path of the carriage, and a backward path landing position, which is a position on the landing target object the ink droplet is to be landed in a backward path of the carriage;
• and
• a gap adjusting process of comparing actual measurement values based on the forward path landing position and the backward path landing position the ink droplet actually lands in the discharging process, and optimum values based on respective optimum landing positions of the forward path landing position and the backward path landing position determined in advance according to a desired gap, and adjusting the length of the gap with the gap adjustment means based on a shift of the actual measurement values and the optimum values.