Patent ID: 6226019
Filing Date: 2001-05-01
Classification: G03G,H04N

Abstract:
An image forming apparatus for forming an image by digital processing comprising:an electrophotographic photosensitive member for bearing an electrostatic latent image formed thereon;image data processing means for processing input image data to a main body of the apparatus into data for forming the electrostatic latent image;electrostatic latent image forming means for forming the electrostatic latent image on the electrophotographic photosensitive member by affecting image exposure by digital optical means conforming to the electrostatic latent image data; anddeveloping means for developing the electrostatic latent image with a toner to thereby form a developed image;wherein the image data processing means effects an image calculation taking into account mutual action around a pixel constituting the electrostatic latent image in conformity with the size of the pixel when it processes the input image data into the electrostatic latent image data, andwherein the potential distribution of an image portion formed by the electrostatic latent image of a dither gradation pattern when the electrostatic latent image is formed by the dither gradation pattern is calculated by the image calculation taking into account the mutual action around the pixel by the image data processing means, and the dither gradation pattern is changed on the basis of the average potential of the potential distribution of the image portion found from the calculation, the average contrast potential which is the potential difference between developing bias potential applied to the developing means and the surface potential of the electrophotographic photosensitive member, and pixel contrast potential which is the potential difference between the potential of the pixel and the potential of the pixels around it.