| 摘要 |
PURPOSE:To enable an automatic copying operation to be carried out with a copying sheet corresponding to a monochromatic document or a color document by a method wherein a document color corresponding mode is set in response to a difference between the first residual charged amount and the second residual charged amount corresponding to the first preliminary exposing operation and the second preliminary exposing operation. CONSTITUTION:The first preliminary exposing operation for radiating a reflected light from a document against a photosensitive member prior to an exposing operation without passing through a color decomposition filter and exposing it and the second preliminary exposing operation for radiating a reflected light from the document against the photosensitive member through a color decomposing filter are carried out for every document. In turn, a charged amount calculation means may calculate residual charged amount at the surface of the photosensitive member detected by a charged amount sensing means after the first and second preliminary exposing operations, calculates the first and second residual charged amounts and stores them in a charged amount memory means. A document color corresponding mode setting means may calculated a difference between the first and second residual charged amounts and if the difference is a predetermined value or less, the document color corresponding mode is set to a color mode. With such an arrangement, a copying with a monochromatic mode or a color mode can be carried out automatically in response to each of the documents. |
