| 摘要 |
PURPOSE:To eliminate a waste originating from unnecessary image formation by detecting transfer paper through plural detectors and controlling a photoscanning range, etc. CONSTITUTION:A line sensor 13 such as a CCD detects whether a transfer form is present or not and its detection signal is outputted through a shift register 16. When the output S2 attains to a high level for the first time, an AND gate 21 is opened to output the high-level output from an FF18 through the gate 21 as the light beam position signal S3 of a photosensitive drum which corresponds to one edge of the transfer form, and then the FF18 is reset with the signal S3. An AND gate applied with an image signal, on the other hand, is also opened with the high-level signal from the register 16 to output an image signal S5 with a controlled print range from the gate 22, limiting the photoscanning range. Similarly, the driving range of a developing device is also limited. Thus, the processing based upon the size of the transfer paper is performed to prevent unnecessary image formation, and a waste is therefore eliminated to prolong the life of components of an electronic copying machine and also reduce its power consumption. |
