Lexmark C910 5055-01x, Service Manual

Page: 19 / 324

General Information
1-5
5055-01x
Processes and Configuration
In this printer, the toner of four colors (magenta, cyan, yellow and
black) melts and deposits on paper, dots which record color image
information. This printing process is called the electrophotography
process.
Electrophotography Process
In the electrophotography process, electrically charged toner,
exposes, develops, transfers, and is cleaned with an aluminum
photosensitive drum. A photoconductive layer forms on the surface
of the drum when the drum is exposed to light.
The surface of the photosensitive drum is negatively charged,
forming the electrostatic image on the surface of the photosensitive
drum. This charge is directed to the photosensitive medium at a low
voltage, reducing the generation of ozone to a very low level. When
the drum surface is charged, the image is recorded by irradiating
light from the LED printhead, forming the electrostatic image. The
LED printhead array along with the Selfoc lens array provide a
single-dot line of the image, in a one-to-one arrangement. The
image data from the printhead controller causes the LED to emit
light in black dots. These black dots form an image of dots on the
photosensitive drum.
The LED printhead minimizes the displacement of images during the
color print process, when images of multiple printheads overlap,
causing dot position accuracy to be much higher. Since light from
the volume of the LED array varies depending on the LED
printheads, the light emitting value is recorded in the EPROM of the
printer controller. When the LED printhead is replaced, the light
emitting value should be entered for each printhead while the printer
is in maintenance mode.
Since the LED printhead and EPROM on the printhead controller
board of this printer are paired, the EPROM on the printhead
controller board should also be replaced whenever the printhead is
replaced.
Service.bk Page 5 Thursday, October 4, 2001 12:20 PM