JPS5737344A - Original placing plate of copying device - Google Patents

Abstract

PURPOSE:To prevent unnecessary toner consumption by laminating and disposing a semitransparent photosemiconductor layer and a storage mode liquid crystal layer, in the form of sandwhich, between the 1st and 2nd transparent electrodes formed on one surface of a transparent substrate, and automatically inverting the peripheral part of the platen to light reflectiveness. CONSTITUTION:If the pulse voltage is applied on a photosemiconductor layer 4 and a liquid crystal layer 5 by closing a switch 8 with a nontransparent original 10 of an area smaller than a platen area held placed on a platen 1, a difference in conductivity occurs in the part A where ambient light is falling and the part B where it is not falling is produced in the layer 4. Therefore, a difference in electric field is produced in the lower layer 5, and the layer 5 in the central part B of the platen 1 covered by the original 10 goes transparent, and the copying of the original 10 is accomplished. On the other hand, the layer 5 in the peripheral part A of the platen 1 not covered with the original 10 goes light diffusive and therefore reflected light is produced, thus black recording of the periphery of the copy is obviated.