| 摘要 |
<p>PURPOSE:To obtain an electrophotographic printer imparting printing density reduced in change even when the voltage of a power source changes, by reading the change in drive voltage to change a pulse width so as to correct said voltage. CONSTITUTION:The printing data from a logical part is sent out to a shift register 1. LED 3 being a light emitting element is driven by a transistor 2, and a pair of transistors and LED are arranged in a row corresponding to the number of printing figures to constitute an LED array. A numeral 4 is a power source line supplying a power source to an LED element and a numeral 5 is a condenser suppressing the instantaneous variation of voltage and a numeral 6 is an A/D converter detecting the variation in the voltage of the power source line 4 to input the same to a microprocessor 7. For example, when the voltage Vcc of the power source drops, the voltage drop is detected by the A/D converter 6 and a driving pulse width is increased by the microprocessor 7 so as to compensate said voltage drop.</p> |
