| 摘要 |
PURPOSE: To obtain high quality printing without disturbing a toner image, even if a photoreceptor having a high dielectric constant and low volume resistance and a printing process in which the surface potential decay of the photoreceptor becomes great are used by providing a reelectrifying mechanism part between a developing part and a transfer part. CONSTITUTION: A reelectrifying unit 13 is installed before a transfer, to reelectrify the toner image on a photoreceptor drum 1. In other words, the photoreceptor developed between a developing mechanism part 2 and a transfer mechanism part 4 is reelectrified to the same polarity as that of primary electrification, to adjust a contrast potential before a transfer unit (the photoreceptor surface potential difference between toner sticking and unsticking parts). When the contrast potential before the transfer unit is smaller than 300V, the shutting in of the toner image by electrostatic force becomes weak and the toner image becomes irregular due to the contact with a paper sheet at the time of transferring, etc., to reduce resolution. For reelectrifying, not normal DC corona electrification but corona electrification by the superimposing of an AC on a DC is used to prevent the overelectrification of toner. |
