Patent ID: 9104130
Filing Date: 2015-08-11
Classification: G03G

Abstract:
1. An image forming apparatus configured to form an image on a recording medium, the image forming apparatus comprising: a plurality of photosensitive members; a plurality of charging devices to which a common charging power source applies a charging voltage to charge the plurality of photosensitive members; an exposure device configured to expose surfaces of the plurality of photosensitive members, which have been charged by the plurality of charging devices, with a first laser power to form a non-image section potential, and expose the surfaces with a second laser power to form an image section potential; a plurality of developing devices configured to make developers adhere to areas in which the image section potential is formed to form developer images on the plurality of photosensitive members; a transfer device to which a transfer voltage is applied to transfer the developer images formed on the plurality of photosensitive members onto a transfer medium so as to sequentially superimpose the developer images on top of each other; and a control portion configured to control a magnitude of the charging voltage applied from the common charging power source and an output of a laser power from the exposure device, wherein the control portion is configured to set a lower limit value of the charging voltage for each of the plurality of photosensitive members, apply the charging voltage having a magnitude not less than any lower limit value from the common charging power source to the plurality of charging devices, and control the output of the laser power for each of the plurality of photosensitive members individually, and wherein the lower limit value for each of a second and subsequent photosensitive members in order of transferring the developer images from the plurality of photosensitive members onto the transfer medium is set based on a density of a developer image formed by a photosensitive member located before a corresponding one of the second and subsequent photosensitive members.