| 摘要 |
<p>PURPOSE:To reduce dispersion in printing density by printing with an LED head which has its light quantity compensated so that the spot width of the light quantity at a specified threshold value of the photosensitive drum provided with a digital characteristic is made constant. CONSTITUTION:A target spot width of the spot width of the light quantity in the specified threshold value is set to a controller (not shown in diagram). The spot width is measured by driving the LED6 of a light emitting diode (LED) head 1A by the controller at each of the LED1 to LEDn. The measured spot width and the target spot width are compared by the controller, and the values of resisters R1 to Rn of a drive IC 7A are set so that the measured spot width becomes the target spot width. Then, the photosensitive drum 3A provided with the digital characteristic is actuated at the specified threshold value. Thus, the dispersion in depth of focus of a lens array 2 and dispersion of printed density due to mounting precision, etc., of the LED chips can be reduced.</p> |
