Patent ID: 8005380
Filing Date: 2011-08-23
Classification: G03G

Abstract:
1. An image forming apparatus comprising: a photosensitive member; a charging device for charging said photosensitive member; an exposure device for exposing said photosensitive member charged by said charging device in accordance with image information; a developing device for developing, with toner, an electrostatic image formed on said photosensitive member by said exposure device into a toner image; a transfer charger for transferring the toner image formed on said photosensitive member by said developing device onto an image receiving member in a transfer portion; pre-exposure means, provided downstream of said transfer charger and upstream of said charging device with respect to a rotational direction of said photosensitive member, for electrically discharging by pre-exposure of said photosensitive member with light; a current detector for detecting a current flowing through said transfer charger; calculating means for calculating an amount of decrease of a photosensitive member potential due to pre-exposure of said photosensitive member; and correcting means for correcting an image forming condition on the basis of the amount calculated by said calculating means, wherein said calculating means determines a property formula on the basis of a first current, detected by said current detector, flowing between said transfer member and an area of said photosensitive member charged by said light discharger which is supplied with a first DC voltage substantially without being discharged by said pre-exposure means, and a second current, detected by said current detector, flowing between said transfer member and an area of said photosensitive member charged by said charging device which is supplied with a second DC voltage substantially without being discharged by said pre-exposure means, and wherein said calculating means calculates a correction amount of said correcting means on the basis of the property formula and a current flowing between said transfer member and an area of said photosensitive member charged by said charging device which is supplied with a predetermined DC voltage with discharging by said pre-exposure means.