| 摘要 |
PURPOSE:To obtain an optional negative or positive copied picture from a negative or positive original by forming a means for setting up transfer corona electrostatic charge having reverse polarity against the polarity of a latent image on a photosensi tive body to a value lower than transfer corona electrostatic charge having the same polarity as that of the latent image at the time of a transfer process. CONSTITUTION:A corona wire of a corona discharger 3 is connected to the output terminal of a plus corona generating high voltage power supply 11 through a high voltage switch, the photosensitive body 1 is uniformly and positively electrostatically charged and then the picture is exposed to form a latent time. An AC voltage obtained by superposing a DC voltage to a developing roller 53 as a developing bias and minus toner 51 is adhered to the dark part D of the plus-charged latent image on the photosen sitive body. Transfer paper 8 is superposed to the developed photosensitive body and plus corona is discharged to the surface of the transfer paper 8 to transfer the latent image to the transfer paper 8. The output terminal of a high voltage power supply 15 is connected to a corona wire of a corona discharger 6 for transfer through a high voltage switch and a plus corona discharging voltage for transfer is discharged to obtain fine transferred picture. |
