JPS54111833A - Original exposure device of copying machines - Google Patents

Abstract

PURPOSE: To prevent the entrance of exposure rays to the operator's eyes even at the copying of thick originals and prevent the unnecessary deposition of toner on the portions of a photoreceptor other than those corresponding to the original by shielding the portions other than those covered with the original with shield masks whose bottom surfaces are reflective.

CONSTITUTION: Shield masks 2,3 whose respective bottom surfaces are coated to a white color are disposed in proximity below contact glass 1. The shield mask 2 has a width OXM which is larger than the transverse width OX_c of the contact galss 1 and is movable in its depth direction, i.e., (y) direction, right under the contact glass 1. The shield mask 3 is disposed right under the shield mask 2 and has a width OYM larger than the depth OY_c of the contact glass 1 and is parallel movable in its transverse width direction, i.e., (x) direction. Both masks 2, 3 are moved by the size signals of the originals. These shield masks 2, 3 shield the leaking light of the exposure rays from the portions other than the original and apply reflected light to the photoreceptor with their bottom surfaces.

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