| 摘要 |
PURPOSE:To eliminate rotational variation by using a piezoelectric element and driving and rotating through a rotary member of a photosensitive drum with a progressive wave generated on an elastic member. CONSTITUTION:The piezoelectric element 21 made of piezoelectric ceramic and a stator 22 consisting of the elastic member having a slotted part 22a fixed on the element 21 are fixed on a base 23 to form the stator part 40 of the driving device. A flange 24 has a plastic slider 25 pressed against the stator 22 and a support part 24a for supporting the photosensitive drum 1 and is pressed against the stator part 40 by a spring 26 to constitute a rotor part 50. When a high frequency current is applied from a rotary transformer 30, respective adjacent sections of the polarized piezoelectric element 21 are opposite in polarization direction from one another to generate such a progressive wave W that the mass point on the surface of the stator 22 is in elliptic motion; and the slider 25 rotates and then the drum 1 is driven to rotate. Consequently, the rotational variation resulting from the interposition of a belt, a gear, etc., is eliminated. |
