| 摘要 |
PURPOSE:To reproduce stable gradation at any time by comparing image data with the pattern signal of a prescribed period and modulating pulse width according to the result, forming an electrostatic latent image by projecting modulated light on a photosensitive body light and adjusting a bias voltage impressed at the time of development while matching to the characteristic of a pattern signal. CONSTITUTION:The reader element 2 of a reader part A reads an original 1, converts an original image into an analog electrical signal, amplifies the result by an amplifier 3, changes it into a digital image by an A/D converter 4 and inputs it in a RAM 10 for correcting gradation used through a latch 5. The D/A converter 13 of a printer part B converts the image data corrected in the RAM 10 into an analog image signal and inputs the obtained signal in a pulse width modulator circuit 14. Then an output signal is amplified by a laser driver 15 and sent to a laser generating device 16. After that, the laser beam from the device is projected on an optical wind drum 19 through a polygon mirror 17 and a ftheta lens 18. Then a bias voltage is impressed on the drum 19 by a corona electrifier 20. At this point, the voltage is adjusted while matching to the correction in the RAM 10. |
