Method for determining working gap, and recording device

A recording device comprising:

• a recording head configured to record a test pattern;
• a gap adjustment unit configured to adjust a height of the recording head;
• an imaging unit configured to capture the test pattern and including a zoom lens;
• and
• a control unit, wherein
• the control unit
• records the test pattern on a first recording medium having a known medium thickness,
• captures the test pattern recorded on the first recording medium in each of a first state where a distance between the recording head and the first recording medium is a first distance, and a second state where a distance between the recording head and the first recording medium is a second distance, and enlarges or reduces, in the first state, an image of the test pattern to be captured in the first state to a predetermined size, by using the zoom lens,
• calculates, based on the number of pixels of the test pattern that has been captured at the first distance and for which the image has been enlarged or reduced in the first state, and based on the number of pixels of the test pattern that has been captured at the second distance, a function to determine the distance from the number of pixels of the captured test pattern,
• records the test pattern on a second recording medium,
• captures the test pattern recorded on the second recording medium, and
• determines, based on the number of pixels of the captured test pattern and the function, a working gap that is a distance between the recording head and the second recording medium.