Laser Exposure; Overview - Ricoh G031 Service Manual

2.2 LASER EXPOSURE

2.2.1 OVERVIEW

This machine uses a laser diode to produce electrostatic images on an OPC drum.
The laser diode unit converts image data from the ECB into laser pulses, and the
optical components direct these pulses to the drum.
Exposure of the drum by the laser beam creates the latent image. The laser beam
makes the main scan while drum rotation controls the sub scan.
Strength of the beam output
Strength of the beam on the drum
Printing
There are two polygon motor speeds:
- G031 -
Resolution (dpi)
600 300/600 dpi printing
1,200
- G032 -
Resolution (dpi)
600 300/600 dpi printing
1,200
Differences between 1,200 dpi and 600 dpi printing
To produce 1,200 dpi, the machine uses a different data frequency for the main
scan and a different line speed for the sub scan, compared with 600 dpi printing.
For 1,200 dpi printing, the polygon motor works at the same speed as for 600 dpi
printing but the data frequency is twice as fast as in 600 dpi printing.
The paper at 1,200 dpi is fed at half the speed used for 600 dpi, as follows.
Paper feed line speed
The beam diameter for 1,200 dpi printing is the same as for 600 dpi printing.
SM
0.636 mW
Binary (2 bits/pixel)
Modes Motor Speed (rpm) Data Frequency (MHz)
1,200 dpi printing
Modes Motor Speed (rpm) Data Frequency (MHz)
1,200 dpi printing
600 dpi printing
92 mm/s
2-5
LASER EXPOSURE
G031
5 mW
Binary (2 bits/pixel)
22478.22
22478.22
22377.62
22377.62
1,200 dpi printing
46 mm/s
G032
5 mW
0.43 mW
22.0926
44.1851
15.0528
30.1056
G031/G032