| 摘要 |
PURPOSE:To attain an original reader with small size and high sensitivity, by using a storage type photosensor as a photosensor, intermitting scanning every time the state of a binary-coded signal is changed in the state, performing signal processing and preventing the irradiation of light to the photosensor during the intermission of the scanning. CONSTITUTION:The light irradiated from a light source 2 illuminates an original 1, the intensity is changed depending on the change in the contrast on the original, the light is reflected and enters an optical system 3, and the image of the original is formed on the storage type image sensor in the optical system 3. The sensor 5 is driven with a scanning circuit 6, the read signal charge is amplified at a preamplifier 7, converted into an integration device 8, and the voltage is discriminated into a black or a white level at a comparator 9 with a threshold value. Every time the binary-coded signal is changed, the scanning is intermitted and the irradiation of light on the sensor is prevented during the intermission. Thus, no generation and storage of light takes place, allowing to keep the storage time constant substantially. |
