Ricoh G148, Service Manual

Page: 446 / 537

Four-Beam Exposure
The LD unit uses four laser diodes to write 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 write 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.
Laser Exposure
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