| 摘要 |
PURPOSE:To cause the prime of write positions of respective beams to coincide with one another by a simple control, by forming a device so that a beam detector is scanned under the state where only selected beams out of plural beams are lit. CONSTITUTION:Counter CT performs such control that only light beam LC passes through beam detector BD under the lit state and other beams pass through detector BD under the extinguished state, and the lighting signal is applied to driving circuit terminal T. Control circuit CONT receives the lighting signal make gate counter groups initiatoly state which form the shift register read clock signal. The dot signal is stored into line buffers LBa-LBc during the time from counting of count value (P) by counter CT up to detection of light beam LC detector BD. Buffers LBa-LBc transmit a dot signal by one-line components to delay circuits DL1-DL2 synchronously with the clock signal from gate circuits Ga-Gc. Light beams La-Lc modulated according to the dot signal by modulating circits Da-Dc are scanned in the photosensitive drum axis direction to form a picture on the drum. |
