PURPOSE: To adjust print density by varying the quantity of erasing light and controlling the surface potential of a photoconductor in a laser beam printer.
CONSTITUTION: The photoconductor 1 is electrostatically charged by an electrostatic charger 2 and exposed to a light beam 3 containing picture information from a laser to form an electrostatic latent image, which is developed by a developing device 4 to form a toner image 6; and this toner image is transferred electrostatically to transfer paper 7. Residual toner 9 on the photoconductor 1 is removed by a cleaner 10 and residual charges on the photoconductor 1 are erased by the erasing light 11 to reuse the photoconductor 1. When the picture density of the transfer toner image 8 on transfer paper 7 is controlled, the surface potential at a development part 4 should be varied, but the surface potential varies in inverse proportion to the quantity of the erasing light, so the surface potential is controlled by the erasing light 11 to adjust the print density easily.
AKIMARU SUSUMU
HOSOYA AKIRA
