Patent ID: 7526238
Filing Date: 2009-04-28
Classification: G03G

Abstract:
1. A development device developing a latent image on an image bearing member of an image forming apparatus, the development device comprising: an electrostatic conveyance device having an electrostatic conveyance surface and configured to move toner particles on the electrostatic conveyance surface in a toner conveyance direction by a phase-shifting electric field, the electrostatic conveyance surface having an upstream side end where the phase-shifting electric field starts and a downstream side end where the phase-shifting electric field ends; a supply device arranged to oppose the upstream side end of the electrostatic conveyance surface of the electrostatic conveyance device to supply the toner particles onto the electrostatic conveyance surface of the electrostatic conveyance device, the toner particles supplied by the supply device onto the electrostatic conveyance surface of the electrostatic conveyance device being moved on the electrostatic conveyance surface by the phase-shifting electric field to a development area of the electrostatic conveyance device opposing the image bearing member for development of the latent image on the latent image bearing member; and a collection device arranged to oppose the downstream side end of the electrostatic conveyance surface of the electrostatic conveyance device and configured to collect the toner particles moved on the electrostatic conveyance surface to a downstream side of the development area of the electrostatic conveyance device in the toner conveyance direction without contributing to the development of the latent image in the development area, wherein the toner particles collected by the collection device are returned to the supply device and wherein the electrostatic conveyance device is circularly formed with the upstream side end and the downstream side end of the electrostatic conveyance surface thereof separated from each other, wherein the electrostatic conveyance device has a second electrostatic conveyance surface between the upstream side end and the downstream side end of the electrostatic conveyance surface thereof and is configured to form the phase-shifting electric field in the second electrostatic conveyance surface in a predetermined timing other than when an image is formed, and wherein the collection device includes a conductive collection member, and a collection electric field is formed between the collection member and the electrostatic conveyance surface of the electrostatic conveyance device and wherein the collection member of the collection device is a conductive plate to which bias voltage of a polarity opposite to that of the toner particles is applied.