| 摘要 |
PURPOSE:To prevent malfunction in a laser printer from occurring by eliminating a signal inputted in a section other than a prescribed section before and after a timing to input line sync as a noise. CONSTITUTION:The output of a photodiode 1 receiving a laser beam for synchronism detection is converted to a digital value by a comparator 2, then, it goes to synchronism detection signal (line sync) input. A CPU 3 detects this purport and outputs an enable signal for a period of n(s) before and after the input timing. Such enable output is inputted to a gate 5, while validates line sync output only for the output period of the enable signal. The line sync output is inputted to the control part (plotter control part) 4 of the laser printer, and picture information is outputted setting the output of the control part as a synchronizing signal, and the plotter control part 4, when receiving the line sync output, returns ACK, and reports the completion of the input of the line sync to the CPU 3. |
