| 摘要 |
PURPOSE:To obtain a copy in the form that part of an image is made black or blank by disposing an optical path opening-closing means that can control shutting- off of rays to an arbitrary region of the cross sectional area of an optical path and controlling the original image exposure region arbitrarily by said means. CONSTITUTION:Nichols crossed polarization filters 7, 8 are provided on the respective outer sides of two sheets of plane glasses 1, 2. 7 is used as a polarizer and 8 as an analyzer, respectively, and both 7, 8 are so disposed as to optically orthogonal or parallel each other. Voltage is applied across opposing transparent electrodes 3, 4 by a power source 9. With such constitution, the light L entering the transparent plane glass 1 from the polarizer 7 side sufficiently transmits through the transparent plane glass 2 and is held in the state of going to the analyzer 8 side while no voltage is applied across the electrodes 3, 4, but when the voltage is applied, the light transmission is shut-off. In this way, the application of light to the drum region surface is prevented during exposure by controlling the conduction of electricity, whereby the image which is made partly, for example, blank is obtained. |
