| 摘要 |
PROBLEM TO BE SOLVED: To accurately detect the pitch of a light beam in a subscanning direction by providing a beam pitch detecting means for calculating the pitch of plural light beams in the subscanning direction based on a detection signal as for the position of each light beam obtained by a position sensor. SOLUTION: The beam is modulated based on an image signal, then, optical writing is performed on a photoreceptor. The image recorder is provided with the position sensor 33 for detecting the position of the beam, a computing element 37 as the beam pitch detecting means, a CPU 39 and a pitch varying control circuit 45, and the computing element 37 is prepared for allowing a light source to emit beams one by one when the rotating speed of the deflecting means is low so that the position of the beam may be detected by the sensor 33, and then, calculating the pitch of plural beams in the subscanning direction based on the detection signal as for the position of each beam obtained by the sensor 33. Thus, even in the case plural beams come close to each other in the subscanning direction at a pitch equal to or below the prescribed pitch and also plural beams overlap each other, the pitch of the beam in the subscanning direction is accurately detected, and the pitch of the beam in the subscanning direction is accurately adjusted. |
