Abstract: An image forming apparatus comprises: at least an image carrier of which rotary shafts extending from both ends thereof are rotatably supported on an apparatus body by bearings; and a charging roller having gap members fixed to both end portions thereof, respectively, wherein the gap members are brought in contact with the peripheral surface of the image carrier with some pressure to form a charge gap between the image carrier and the charging roller so that the charging roller charges the image carrier in non-contact state with the charge gap, and wherein the gap members are each formed to have a small-diameter portion on the inside thereof and a large-diameter portion on the outside thereof such that the respective small-diameter portions are positioned to face each other.

Abstract: A charging roller, adapted to face an image carrier at a predetermined charging gap and charge the image carrier in a non-contact state, including: a conductive shaft, provided with a pair of annular concave portions formed on an outer circumferential surface at both ends thereof; a conductive layer, formed on the outer circumference surface at a center portion of the conductive shaft defined between the pair of concave portions; and an insulating layer, formed on the outer circumferential surface at outer portions of the conductive shaft from the pair of annular concave portions.

Abstract: A rotary drive device is configured to be reduced in size while still delivering a prescribed torque. The rotary drive device has a base part with a vibrating body and a rotating body attached to the base part. The vibrating body has at least one piezoelectric element that vibrates an abutting part, which rotates the rotating body. Specifically, the rotating body has a contact part that is positioned at a prescribed distance from the rotational center and that is abutted against by the abutting part. When voltage is applied to the piezoelectric element, the vibrating body vibrates to repetitively press the abutting part against the contact part to rotate the rotating body. The vibrating body is positioned in a plane that intersects the rotational axis of the rotating body, and is disposed at least as close to the rotational axis of the rotating body as that of the contact part.

Abstract: A rotary drive device is configured to be reduced in size while still delivering a prescribed torque. The rotary drive device has a base part with a vibrating body and a rotating body attached to the base part. The vibrating body has at least one piezoelectric element that vibrates an abutting part, which rotates the rotating body. Specifically, the rotating body has a contact part that is positioned at a prescribed distance from the rotational center and that is abutted against by the abutting part. When voltage is applied to the piezoelectric element, the vibrating body vibrates to repetitively press the abutting part against the contact part to rotate the rotating body. The vibrating body is positioned in a plane that intersects the rotational axis of the rotating body, and is disposed at least as close to the rotational axis of the rotating body as that of the contact part.

Abstract: A rotary drive device is configured to be reduced in size while still delivering a prescribed torque. The rotary drive device has a base part with a vibrating body and a rotating body attached to the base part. The vibrating body has at least one piezoelectric element that vibrates an abutting part, which rotates the rotating body. Specifically, the rotating body has a contact part that is positioned at a prescribed distance from the rotational center and that is abutted against by the abutting part. When voltage is applied to the piezoelectric element, the vibrating body vibrates to repetitively press the abutting part against the contact part to rotate the rotating body. The vibrating body is positioned in a plane that intersects the rotational axis of the rotating body, and is disposed at least as close to the rotational axis of the rotating body as that of the contact part.