| 摘要 |
PROBLEM TO BE SOLVED: To reduce the influence of step vibration to form a good-quality reproduced image while securing the rotational accuracy of a photoreceptor by directly driving the photoreceptor with a stepping motor and specifying the frequency of an exciting phase switching signal given to a driving circuit to circumferential speed of the photoreceptor. SOLUTION: The photoreceptor drum 41 is directly connected to the driving shaft 411 of the stepping motor 410, and the rotation of the motor 410 is controlled by supplying a driving pulse by switching an exciting phase in the motor 410 based on a predetermined exciting system every time a clock pulse (exciting phase switching pulse) as a speed control signal is received from a control part. Relation between the frequency fp(Hz) of the exciting phase switching signal given to the driving circuit 430 of the motor 410 and the circumferential speed V (mm/sec) of the photoreceptor is set to fp/V>=2.0. Even when the unevenness of pitch is caused by the step vibration it is not recognized as a stripe pattern by human eyes and the deterioration of the reproduced image may be prevented. |
