| 摘要 |
PURPOSE:To detect exactly picture density of an original by constituting a titled device so that the preliminary scanning can be executed extending over the whole surface of the original. CONSTITUTION:A reflected light of an original 109 exposed by an original illuminating lamp 108 passes through a lens 110, and thereafter, an electrostatic source latent image of an original picture is formed on the surface of a photosensitive drum. In a controlling circuit 121, a transfer paper size is detected from a signal 125S from a transfer paper containing part 125, its size width becomes a preliminary scanning width L, an inverted position of an optical system is determined, and the preliminary scanning for determining an original exposure quantity is started. In an AE circuit 122, a potential sensor output 123S is inputted extending over a period corresponding to the width L, and a digital converted value DVAE of its integral value VAE is stored in a memory RAM. While an operation for resetting the optical system whose measurement of the original density is ended, to its home position is executed, an operation for determining the lighting voltage of the original illuminating lamp 108 basing on the integral value DVAE is executed. |
