Patent ID: 7572076

Claim:
A printer comprising: a printing part printing inputted printing information on a printing medium while the printing part moves by gravity; a support supporting the printing part and the printing medium facing each other so that one of the printing part and the printing medium is movable in a gravity direction; a light emitter moving together with the printing part; a light receiver placed facing the light emitter and moving together with the printing part; an indicator with light transmittance placed between the light emitter and the light receiver and having a plurality of light-shielding portions arranged in a gravity direction at predetermined intervals; a counter counting the number of times that the light receiver receives light from the light emitter; and a timer measuring a printing time, wherein the printing part corrects the inputted printing information according to a moving distance and a moving speed of one of the printing part and the printing medium and prints corrected printing information on the printing medium, and wherein the moving distance is calculated based on a count value of the counter, and the moving speed is calculated based on the count value of the counter and a printing time measured by the timer.