IMAGE FORMING APPARATUS

• Main Authors: HIRAI HIDEJI, KANEKO SATOSHI, OCHI TERUMICHI
• Format: Patent
• Language: English; Japanese
• Published: 01.12.2016
• Subjects: CINEMATOGRAPHY; ELECTROGRAPHY; ELECTROPHOTOGRAPHY; HOLOGRAPHY; MAGNETOGRAPHY; PHOTOGRAPHY; PHYSICS

PROBLEM TO BE SOLVED: To suppress the occurrence of unevenness in image density caused by unevenness in electric resistance of charging rollers without using a contact/separation mechanism for bringing the charging rollers into contact with or separating the charging roller from photoreceptors and conductive rollers.SOLUTION: An image forming apparatus comprises: current detection means (79Y, 79C, 79M, and 79K) that detect currents flowing between photoreceptors (20Y, 20C, 20M, and 20K) and charging rollers (71Y, 71C, 71M, and 71K) to which voltages output from charging power supplies (12Y, 12C, 12M, and 12K) are applied; and a control part 110 that grasps unevenness in electric resistance in a direction of rotation of the charging rollers on the basis of results of detection performed by the current detection means, performs, at a predetermined timing, data construction processing of constructing change pattern data for changing output values of voltages output from the charging power supplies on the basis of a result of the grasp, and performs, in a print job, voltage changing processing of charging the photoreceptors while changing the output values of the voltages output from the charging power supplies on the basis of the change pattern data.SELECTED DRAWING: Figure 6 【課題】帯電ローラを感光体や導電性ローラに接離させるための接離機構を用いることなく、帯電ローラの電気抵抗ムラに起因する画像濃度ムラの発生を抑える。【解決手段】帯電電源（１２Ｙ，Ｃ，Ｍ，Ｋ）から出力される電圧が印加される帯電ローラ（７１Ｙ，Ｃ，Ｍ，Ｋ）と感光体（２０Ｙ，Ｃ，Ｍ，Ｋ）との間に流れる電流を検知する電流検知手段（７９Ｙ，Ｃ，Ｍ，Ｋ）を設け、電流検知手段による検知結果に基づいて帯電ローラの回転方向における電気抵抗ムラを把握し、その結果に基づいて帯電電源からの電圧の出力値を所定のパターンで変化させるための変化パターンデータを構築するデータ構築処理を所定のタイミングで実施し、且つ、プリントジョブにて、その変化パターンデータに基づいて帯電電源からの電圧の出力値を変化させながら感光体を帯電させる電圧変化処理を実施する制御部１１０を設けた。【選択図】図６