PURPOSE: To obtain copies which differ in hue from the same printing master without mixture by cleaning the substrate photoconductor of the printing master with a cleaning and developing roll on every printing process of a desired number of sheets.
CONSTITUTION: In regard to a cleaning preprocessing, in the 1st cleaning preprocessing, a cleaning corotron 22 is provided in front of the cleaning and developing roll so as to decrease the amount of electrostatic charge of residual toner on the photoconductor as the substrate of the printing master, and when the printing master is cleaned up, the printing master is irradiated with coronas from the cleaning corotron 22 firstly to decrease the amount of electrostatic charge of the residual toner on the printing master. Then, the cleaning operation of the cleaning and developing roll is performed additionally to remove the residual toner from the printing master easily, so the photoconductor as the substrate of the printing master is cleaned up excellently.
YAKABE YUTAKA
KAGEYAMA TOSHIICHI
YOSHINO MASAMI
CHIKUGI TOSHIYUKI
