| 摘要 |
PURPOSE:To obtain a bicolor image free of color mixing by increasing the potential of the 1st red electrostatic latent image and decreasing the potential of a succeeding black electrostatic latent image to <=2/3 when forming electrostatic latent image in two red and black colors in an insulating layer on a photoreceptor. CONSTITUTION:On a conductive substrate of Al, etc., a photoconductive layer and an insulating layer are provided to constitute a photosensitive drum 1. The photoreceptor 1 is charged primarily by a primary corona dischager 11 and the control grating is applied with a bias voltage by using a secondary corona discharger 12 to irradiate the insulating layer with reflected light beams 27a and 27b from a two-color original through a cyan filter 13 and a red filter 14 simultaneously with the secondary charging. As a result, potentials of respective red, white and black areas of the photoreceptor 1 are +300, -80 and -100V, respectively. Thus, the contrast of the red latent image is <=2/3 as high as that of the black latent image, so an excellent image free of color mixing is developed through red and black developing devices 15 and 17. |
