| 摘要 |
PURPOSE:To prevent the degradation in image quality by an erroneous mode selection by detecting the density at every microarea of the reflected light from a document with a density sensor prior to copying processing and setting a photograph mode when the change state thereof is a continuous gradation. CONSTITUTION:A light source 2b is prescanned and the reflected light from the document A is read by photodetecting sensors 3, 4 to detect the density of the microarea on the document surface. The changing state of the density is changed by whether the document A is a photograph document or other documents, such as character documents. Since the gradation of the photograph document changes continuously, the density of the microarea eventually shifts continuously. On the other hand, the density of the image changes extremely sharply and the density of the microarea changes partially extremely sharply at the point where there is a character and not in the case of, for example, the character document. Namely, whether the document A is the photograph document or the document of the character, etc., is easily discriminated according to whether the reflected light from the document is the continuous gradation or not. The photograph mode is set in the case of the continuous gradation. |
