Four-Beam Exposure - Ricoh MT-C1 Service Manual

15 February 2006

6.7.3 FOUR-BEAM EXPOSURE

The LD unit uses four laser diodes to scan
four lines simultaneously. The diodes are
fixed at 1200 dpi, so beam pitch
adjustments are not required.
The diagonal arrangement of the four
beams achieves 1200 dpi.
600 dpi 8-bit scanner data is converted to
1200 dpi 1-bit digital data during image
processing.
When edge processing or smoothing (FCI
fine character adjustment) is used, one-bit
data is converted to grayscale data in the
LD driver circuit board.
Greyscale control: The greater the
exposure time of the laser beam, the darker
the pixel. The duration (width) of the pulse
is adjusted with PWM (pulse width
modulation) in 5 steps.
Sub Scan
CH3
CH4
6-47
LASER EXPOSURE
B246D902.WMF
CH1
CH2
Main Scan
B246D903.WMF