Development apparatus and image forming apparatus using the same

摘要

A development apparatus and an image forming apparatus wherein optical high-precision detection of the toner amount of a toner layer formed on a toner carrying member is ensured even when the great amount of the toner is deposited on the toner carrying member by transferring all or a part of the toner on the surface of the toner carrying member onto a detecting roller, and wherein stable images are provided at all times.

主权项

1. A development apparatus, comprising:
a toner carrying member configured to be supplied with toner, in a toner-supply area, and hold and carry the toner on a surface thereof, and convey the toner to an image carrier facing the toner carrying member, so as to develop an electrostatic latent image formed on the image carrier, wherein the toner is carried on a toner carrying area on the surface of the toner carrying member, said toner carrying area being broader in the direction of an axis of rotation of the toner carrying member than an image forming area on a surface of the image carrier in the direction of an axis of rotation thereof; a detecting roller provided on a downstream side from the toner-supply area so as to face the toner carrying member, the detecting roller configured to hold and carry at least part of the toner transferred from a non-facing part of the toner carrying area on the surface of the toner carrying member so that an amount of the toner on the non-facing, part is reduced, said non-facing part not facing the image forming area of the image carrier; a toner detecting device configured to detect optically quantity of the toner transferred to and held on said detecting roller, or quantity of the toner remaining on said non-facing part of the toner carrying area without having been transferred to said detecting roller; a controller configured to control transfer of the toner from the toner carrying member to the detecting roller so that a thickness of a toner layer formed on the detecting roller is smaller than a thickness of a toner layer formed on the toner carrying member before the toner being transferred to the detecting roller; and wherein said controller is configured to control detection of quantity of the toner on said detecting roller by said toner detecting device so that the detection is conducted in the course of forming an image by developing an electrostatic latent image formed on the image carrier.