PURPOSE: To prevent the degradation of image quality caused by surface fogging by relatively moving first and second grids, shifting meshes formed on these grids and changing the rates of the perforations of the grids.
CONSTITUTION: The first grid 3 disposed opposite to an electrostatic latent image carrier 1, and the second grid 4 is disposed opposite to the side of the electrostatic latent image carrier 1, on the side of the electrostatic latent image carrier compared with the first grid 3 are provided. The meshes are formed on the first and second grids 3 and 4, and they are relatively moved to shift the meshes, so that the ratios of the perforations of the grids are changed and the surface potential of the electrostatic latent image is changed. For instance, when the temp. of an image forming device is low, the ratios of the perforations of the grids are high, and they are low when the temp. is high. Thus, the occurrence of the surface fogging at the time of rising and low temp. of the image forming device, is prevented, and stable excellent image quality is always obtained.
KOGA YOSHITOMO
KOJIMA TETSUJI
SUNAGA NAOKI
