| 摘要 |
PROBLEM TO BE SOLVED: To reduce toner left on a photoreceptor and provide superior transcription by monitoring transition of transcription efficiency of each toner pattern transcribed on a recording paper sheet and changing developing and transcription conditions. SOLUTION: A CPU controls a DC voltage component value based on detection results of a toner adhesion detection sensor on a photoreceptor so as to respond to changes in developing characteristics caused by environment. Before starring copying or in setting a prescribed mode, the CPU 14 forms a plurality of toner patterns of the same density on a photosensitive drum 23 and transcribes them on a recording paper sheet, while cascadingly changing a charge wire current (μA), which is outputted on a transcription charger 38 by a transcription charger HV power supply 212, according to each toner pattern. Then, it detects the density of the each toner pattern transcribed as the data expressing the transcription efficiency of each transcription output and controls Vp-p value of the peak-to-peak voltage of a sine wave of developing bias as developing conditions based on the detection values. |
