Patent ID: 6701116
Filing Date: 2004-03-02
Classification: G03G

Abstract:
A quadruple-tandem type image forming apparatus, disposing four units of an image forming unit comprising: a photosensitive body, a charger for charging the photosensitive body to a prescribed potential, an exposure device for forming an electrostatic latent image on the photosensitive body, and a developing unit for forming a toner image on the photosensitive body, the toner images being transferred to a transfer material sequentially,wherein surface potentials of the photosensitive body in each image forming unit are defined as V0a, V0b, V0c, V0d from upstream toward downstream in a moving direction of the transfer material, development bias voltages in each image forming unit are defined as VBa, VBb, VBc, VBd, and charge quantities of toners in the developing units in each image forming unit are defined as qa, qb, qc, qd, and the following relation is fulfilled: V0a&gE;V0b&gE;V0c&gE;V0d VBa&gE;VBb&gE;VBc&gE;VBd qa&gE;qb&gE;qc&gE;qd (wherein V0a>V0d, VBa>VBd, qa>qd), andwherein ratios of the surface potentials of the photosensitive body to the development bias voltages in each of the image forming units are substantially the same.