Gap control method for a media processing device, and a media processing device

A media processing device comprising:

• a media transportation path;
• a media transportation mechanism that conveys a recording medium through the media transportation path;
• a reading position and a printing position disposed to the media transportation path along the media transportation direction;
• a magnetic head that reads magnetic ink characters printed on the recording medium passing the reading position;
• a printhead that prints on the recording medium passing the printing position;
• a platen disposed opposite the printhead to define the printing position;
• a gap changing mechanism that sets the gap between the printhead and the platen to a first gap or a second gap that is wider than the first gap by moving the printhead in a direction approaching and a direction away from the platen;
• a media detection device that detects passage of a printing area in which the magnetic ink characters are printed on the recording medium passed the reading position;
• and
• a gap control unit that sets the gap to the second gap until the printing area on the recording medium is detected to have completely passed the reading position, and returns the gap to the first gap when the printing area on the recording medium is detected to have completely passed the reading position.