| 摘要 |
<p>PURPOSE: To provide an electronic drive circuit for a multi-laser thermal printer in which uniform printing by all the lasers can be insured and the laser light level can be maintained at a desired value throughout the service life of the laser. CONSTITUTION: A first data feedback loop from RCM66 through CPU 96 to a D/A converter 52 sets a threshold drive current to a laser. A second data feedback loop from a light sensor 40 through CPU 96 and a digital control potentiometer 54 to a second D/A converter establishes a level of an enable drive current to the laser, and the full-on light power output of the laser that is calibrated accurately by this is obtained. This circuit is periodically re- calibrated, and by this, the laser light power output level remains constant for a given data command throughout the service life of the laser in spite of ageing.</p> |
