Panasonic DP-180/190, Service Manual

Page: 170 / 296

170
UF-9000
JAN 2004
Ver. 1.0
DP-180/190
6.3.2. Print Process
6.3.2.1. Charge
The charge corona applies a high, uniform positive charge to the surface of the organic photoconductor
(OPC) drum. The charge level is approximately 900 VDC and remains because the OPC drum has a high
electrical resistance when concealed in darkness.
6.3.2.2. Exposure
The laser beam passes through the collimator lens, is reflected by the polygon mirror, and is focused onto
the drum after passing through an image-forming (
) lens and a reflection mirror. Wherever the laser
beam strikes the drum, the positive charge dissipates. A latent electrical image of two different voltages
potentials, which corresponds to the original page, is formed on the OPC drum.
6.3.2.3. Development / Cleaning
Development:
Non-magnetic toner is supplied to the conductive roller by the toner supply roller. The toner on the
conductive roller is positively charged by friction with the toner supply roller, and the doctor blade ensures a
thin layer on the surface of the conductive roller. Wherever the conductive roller touches the drum, the
positively charged toner is attracted to the latent image on the drum, and the latent image is converted to a
visible toner image. A bias voltage of approx. 350 VDC is applied to the conductive roller to achieve