Exposure - Printronix L5000 Series Maintenance Manual

Exposure

When the photoreceptor drum (which has been positively and uniformly charged in
the main charging step) is exposed to light, the exposed areas of the photosensitive
drum surface film go into conduction. Thus the charge in the exposed area is
neutralized while the unexposed portions of the drum maintain approximately +580
volts. The electrical pattern formed by this process is called the "latent image."
The printer draws on this principle. A bit-mapped image of the page, received from
the host computer, is contained in random access memory (RAM), on the processor
board. The image data illuminates the LED array (see note following), and the drum
rotates to form an electrostatic latent (invisible) print image on the positively-
charged surface.
NOTE: The LED array consists of LED elements which are arranged in the
Principles of Operation
direction of printing width and related to printing pixels on a one-to-one
basis. It converts one raster (horizontal scanning line) of image data into a
row of illumination dots.
LED array
5–9