IMAGE FORMING DEVICE

• Main Author: YAGUCHI KAZUTAKA
• Format: Patent
• Language: English; Japanese
• Published: 22.03.2018
• Subjects: CINEMATOGRAPHY; ELECTROGRAPHY; ELECTROPHOTOGRAPHY; HOLOGRAPHY; MAGNETOGRAPHY; PHOTOGRAPHY; PHYSICS

PROBLEM TO BE SOLVED: To accurately find a surface potential of a photosensitive drum and to reduce a time required for improving an image quality and a contrast adjustment.SOLUTION: An image forming device includes: a photosensitive drum 201; an exposure device 2071 having a laser beam source 207; a transfer roller 204; a high voltage power source 302; a current detection circuit 301; a control part 208 for finding a surface potential of the photosensitive drum 201 based on a discharge start voltage (S300); and the control part 208 for adjusting a light volume of the laser beam source 207 (S304 to S307) so that the value of the current flowing through the current detection circuit 301 becomes a target current value corresponding to a predetermined surface potential of the photosensitive drum 201. The control part 208 sets a target current value based on a potential difference between the surface potential of the photosensitive drum 201 obtained on the basis of the discharge start voltage and the predetermined surface potential (S301) and the value of the current detected by the current detention circuit 301 respectively when two or more different voltages are applied by the high voltage power source 302 (S302 and S303).SELECTED DRAWING: Figure 5 【課題】精度よく感光ドラムの表面電位を求め、画質の向上とコントラスト調整に要する時間を低減すること。【解決手段】感光ドラム２０１と、レーザ光源２０７を有する露光装置２０７１と、転写ローラ２０４と、高電圧電源３０２と、電流検知回路３０１と、放電開始電圧に基づいて感光ドラム２０１の表面電位を求める（Ｓ３００）制御部２０８と、電流検知回路３０１に流れる電流の値が、感光ドラム２０１の所定の表面電位に対応する目標電流値となるように、レーザ光源２０７の光量を調整する（Ｓ３０４〜Ｓ３０７）制御部２０８と、を備え、制御部２０８は、放電開始電圧に基づき求めた感光ドラム２０１の表面電位と所定の表面電位との電位差と（Ｓ３０１）、高電圧電源３０２により２以上の異なる電圧を印加したときに電流検知回路３０１によりそれぞれ検知された電流の値と、に基づいて、目標電流値を設定する（Ｓ３０２、Ｓ３０３）。【選択図】図５