| 摘要 |
PROBLEM TO BE SOLVED: To easily and accurately prevent base fog which is caused by the existence of an end area where an amount of light on a platen is insufficient, and to prevent the base fog while enabling the copying of the image of the original document in the case where the original document has the image at the front end in a reading direction. SOLUTION: The machine is equipped with a development-bias control means which, when at least an area of a latent image at the front end of the original document in the reading direction is developed, can alter a development-bias voltage of a voltage value (VBB) which makes a difference between the potential (VK) of the background of the image of the original document and the development bias voltage larger than the difference between the background potential and an ordinary development bias voltage (VBO) which is applied to other areas of the latent image of the original document. Also, the development bias voltage (VBB) during the alteration is set to a voltage value which does not exceed the potential (VS or VMAX) of the highest-density area. |
