Patent ID: 7284924

Claim:
A printer comprising: a motor; an encoder, adapted to be opposed to a scale provided with a plurality of marks or slits arranged in a first direction at predetermined intervals; comprising: a plurality of detectors, arranged in a second direction perpendicular to the first direction while being staggered in the first direction, each of which detects a position of each of the marks or slits, and the plurality of detectors being operable to respectively output an detection signal which has a first frequency; a first signal generator, which is operable to generate a first output signal which has a second frequency which is 2 n -times of the first frequency based on the detection signal output from a first detector of the plurality of detectors; a second signal generator, which is operable to generate a second output signal which has the second frequency based on the detection signal output from a second detector of the plurality of detectors; a third signal generator, which is operable to generate a third output signal which has the second frequency based on the detection signal output from a third detector of the plurality of detectors; and a fourth signal generator, which is operable to generate a fourth output signal which has the second frequency based on the detection signal output from a fourth detector of the plurality of detectors; and a controller, which is operable to perform a switching control between a first predetermined control based on one of: 1) the first output signal and the third output signal; or 2) the second output signal and the fourth output signal output from the encoder, and a second predetermined control based an the fast output signal, the second output signal, the third output signal, and the fourth output signal.