| 摘要 |
PURPOSE:To prevent giving rise to a dark part at the edge of an image formed by presetting according to the result of detection by a light detection means the voltage applied to a charger, and causing the preset voltage to be output from the end of a document only for a certain period of time. CONSTITUTION:An amplifier 17 for amplifying output signals of a photo sensor 16 is connected to the photo sensor 16 and a CPU 18 is provided for controlling the voltage applied to a charger. The CPU 18 has an output port 20 and the charger for a charging unit 10 is connected to the output port 20. When scanning of a document is started the quantity of light at a predetermined position in front of the end of the document is detected by the sensor 16 and the voltage applied to the charger is set by the CPU 18 according to the quantity of light and is output from the end of the document only for a certain period of time. Therefore, the quantity of light is prevented from becoming insufficient due to a failure to turn on an exposure lamp at the optical end of the document resulting from a shortage of extra repeating time, and image deterioration can thereby be prevented. |
