IMAGE FORMING APPARATUS

• Main Authors: UEMATSU YUICHIRO, HIRAI HIDEJI, SUZUKI SHINGO, KANEKO SATOSHI, GOTO KEITA, AKATSU SHINICHI, MUTO TETSUYA
• Format: Patent
• Language: English; Japanese
• Published: 16.11.2017
• Subjects: CINEMATOGRAPHY; ELECTROGRAPHY; ELECTROPHOTOGRAPHY; HOLOGRAPHY; MAGNETOGRAPHY; PHOTOGRAPHY; PHYSICS

PROBLEM TO BE SOLVED: To suppress occurrence of scumming and adhesion of a carrier in changing a bias from a constant value to the one that fluctuates according to a fluctuation waveform, while suppressing occurrence of unevenness in image density due to periodic fluctuation of a development gap.SOLUTION: An image forming apparatus switches processing to make output of a developing bias constant at a central value Pc to processing to periodically fluctuate the output of the developing bias on the basis of a developing correction data table, after starting a print job at a time point t0, upon arrival of a time point 2 at which rotation speed of a photoreceptor is stabilized, through a time point HP at which rotation angle attitude detection means detects that the photoreceptor has taken a predetermined rotation angle attitude, at timing at which a predetermined time ta has elapsed from the time point HP. The above-described timing is, as illustrated in the figure, timing at which a periodic fluctuation waveform of the developing bias becomes the central value Pc.SELECTED DRAWING: Figure 17 【課題】現像ギャップの周期的な変動に起因する画像濃度ムラの発生を抑えつつ、バイアスを一定値から変動波形に従って変動するものに切り替える際の地汚れやキャリア付着の発生を抑える。【解決手段】時点ｔ０でプリントジョブを開始した後、感光体の回転速度が安定化する時点２が到来してから、回転角度姿勢検知手段によって感光体について所定の回転角度姿勢になったことが検知された時点ＨＰを経て、更に時点ＨＰから所定時間ｔａが経過したタイミングで、現像バイアスの出力を中心値Ｐｃで一定にする処理から現像補正データテーブルに基づいて周期的に変動させる処理に切り替えるようにした。前述のタイミングは、図示のように、現像バイアスの周期的な変動波形が中心値Ｐｃになるタイミングである。【選択図】図１７