| 摘要 |
PURPOSE:To stabilize image quality by using plural developing means, different in development saturation density, for successively developing the multivalue dot latent images of the electrophotographic printer expresses halftone print information through the multi-valued dither method. CONSTITUTION:An electric signal fetched in a laser modulation unit 1 is emitted as modulated laser beams to scan a photosensitive drum 4 in the longitudinal direction through a mirror 2 and a lens 3. The drum 4 rotates in the direction of an arrow to enable the 2-dimensional scanning by the laser beams. The drum surface is leveled in potential with an AC destaticizer 5, and electrostatically charged to -600V with a charger 6. Then, it is exposed to laser beams to form a dot latent image using the 3-valued dither method on the drum 4 by the image scanning system. It is developed twice, and the development characteristics are shown in the graph, and even if the contrasts M, H of a latent image changes somewhat, saturation development density DM, DH can be kept constant. As a result, the image quality can be stabilized by successively developing multivalued dot latent images with plural developing means different in development saturation density. |
