Patent ID: 6330412
Filing Date: 2001-12-11
Classification: H04N

Abstract:
An electrophotographic apparatus comprising:a photosensitive member having an amorphous silicon photosensitive layer, said photosensitive member having an electrostatic image characteristic that varies along a longitudinal direction of said photosensitive member;electrostatic image forming means for forming an electrostatic image on said photosensitive member, said electrostatic image forming means including charging means for charging said photosensitive member and exposure means for exposing said photosensitive member, charged by said charging means, in accordance with an image signal; anddeveloping means for performing reverse development of an electrostatic image formed on said photosensitive member with a developer;wherein said charging means is a corona discharge device including a wire electrode, and a distance between said wire electrode and said photosensitive member varies in the longitudinal direction; andwherein a maximum potential difference .DELTA.VD (volt) in a potential of a dark portion of the electrostatic image in the longitudinal direction, a maximum potential difference .DELTA.VL in a potential of a light portion of the electrostatic image in the longitudinal direction, a value ""a"" (1/volt) corresponding to a ratio of (variation amount in density, in the longitudinal direction, in an image formed by developing the light portion with said developing means)/(the maximum potential difference .DELTA.VD) and a value ""b"" (1/volt) corresponding to a ratio of (variation amount in density, in the longitudinal direction, in an image formed by developing the light portion with said developing means)/(the maximum potential difference .DELTA.VL) satisfy a relation:-0.3.ltoreq.a.times..DELTA.VD+b.times..DELTA.VL.ltoreq.0.3,where 100.gtoreq..vertline..DELTA.VD.vertline..gtoreq.20 and 100.gtoreq..vertline..DELTA.VL.vertline..gtoreq.20.