| 摘要 |
PURPOSE:To attain magnification and reduction with high print quality by changing the scanning speed of light beam and also changing the luminous intensity of a semiconductor laser to apply printing of a character with variable power. CONSTITUTION:In magnifying a character, since the light beam in the main scanning direction is continuous, the time lighting the semiconductor laser 1, that is, a modulating frequency is varied electrically to expand easily the spot width. Variable power is attained by changing the number of turnings of a polygon deflector 2 in the subscanning direction by means of a motor driver 12 or changing the speed of a photosensitive body 4 to change the scanning speed. Then a nonscanning part A is caused with a constant beam diameter. Thus, the spot diameter of the laser beam is increased so as not to cause the part A and pack character dots completely. The laser current value is changed to change the luminous intensity in order to change the spot diameter.
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