Patent ID: 8682236
Filing Date: 2014-03-25
Classification: G03G

Abstract:
1. An image forming apparatus, comprising: a first endless transfer belt to carry a toner image thereon after a primary image transfer operation onto a surface of the first endless transfer belt during rotation of the first endless transfer belt; first extension members around which the first endless transfer belt is extended; at least one first transfer electric field generator disposed inside of a loop of the first endless transfer belt; a secondary transfer unit disposed outside of the loop of and at least partially facing the first endless transfer belt to transfer the toner image onto a transfer medium conveyed by the secondary transfer unit; and an ultrasonic vibration generator to generate ultrasonic vibrations, the ultrasonic vibration generator being disposed inside the loop of the first endless transfer belt and including a vibration imparting part from which the ultrasonic vibrations are applied to an inner face of the first endless transfer belt, wherein the secondary transfer unit is disposed facing and in contact with a first surface portion of the first endless transfer belt to form a transfer nip therebetween, through which the transfer medium is conveyed when the toner image is transferred onto the transfer medium in a secondary image transfer operation, the secondary transfer unit including a secondary transfer roller that faces and contacts an inner face of a second endless transfer belt in the transfer nip to contact the first endless transfer belt via the second endless transfer belt, wherein the transfer nip has a transfer electric field due to a difference in electric potential between the first endless transfer belt and the secondary transfer unit, wherein the first transfer electric field generator contacts the inner face of the first surface portion of the first endless transfer belt in the transfer nip and the secondary transfer unit presses against the first endless transfer belt at a position along the first endless transfer belt opposite the first transfer electric field generator with the first endless transfer belt interposed therebetween, wherein the vibration imparting part of the ultrasonic vibration generator contacts the first endless transfer belt at an intermediate position between a contact point of the first transfer electric field generator with the first endless transfer belt and a contact point of the secondary transfer unit with the first endless transfer belt in a direction of rotation of the first endless transfer belt, and wherein the vibration imparting part of the ultrasonic vibration generator contacts the first endless transfer belt at a position upstream from the contact point of the secondary transfer unit with the first endless transfer belt in a direction of rotation of the first endless transfer belt.