| 摘要 |
<p>PURPOSE:To prevent the variance of the density of display images or the like to obtain stable images by detecting an electric current value supplied to a toner and determining the signal intensity modulated with a picture signal or the DC voltage value applied across a photosensitive body substrate and the toner in accordance with the detected value. CONSTITUTION:The current value supplied to the toner is detected by a current detector 23 before actual display image formation, and servo is applied to a DC power source 21 or a laser driver 22 through a control part 24 or 25 in accordance with the difference between the detected value and a stored correct current value. The applied voltage across a photosensitive body 1 and a developing sleeve 4 or the output of a semiconductor laser 7 is controlled. This current detection is performed in an overall black writing area 30. For example, a signal generator which generates an overall black writing signal is provided in the device itself, and the signal which turns on continuously the laser 7 is outputted from this generator to perform overall black writing.</p> |
