| 摘要 |
PURPOSE:To correct a light quantity by simple constitution, by constituting a titled device so that a bias exposure of a light quantity for compensating roughly an illuminance drop portion with respect to an image forming body surface part having a low image exposing illuminance generated by an influence of a cosine four power rule, etc. of an image forming optical system is given by a bias exposure light source, at the same time as an image exposure to the image forming body surface. CONSTITUTION:l is image exposing light which is made incident on a slit exposing part surface of a photosensitive drum 10 from an image forming optical system, and an exposure quantity distribution of its exposing light has an uneven distribution as shown by a curve (4) of a graph. l25 is bias exposing light which is made incident on the slit exposing part surface of the photosensitive drum by turning on miniature lamps 25, 25 being bias exposure light sources, and an exposure quantity distribution running along the longitudinal direction of the slit exposing part surface of the photosensitive drum of the bias exposing light concerned is formed so as to show a distribution like a curve (5) of the graph. In this state, when bias exposures l25, l25 by the miniature lamps 25, 25 are given at the same time as the image exposure l to the photosensitive drum 10, the halftone light quantity running along the longitudinal direction of the slit exposing part surface of the photosensitive drum is equalized roughly as to each part as shown by a straight line (6) of the graph, by those exposure lights l, l25 and l25. |
