Ricoh V-C3 D081, Field Service Manual

Page: 325 / 1092

4. Do SP2109-014, select Pattern 14, and print a test pattern. ( >Printing Test Patterns)
Color Registration Errors
• In addition to the SP adjustments printed on the seal attached to the LD unit, if color registration errors
occur immediately after you change the laser unit, an additional adjustment is required.
• This additional adjustment is normally not required in the field. Do it only if you see color registration
errors in test prints.
• See "Color Registration Test and Error Adjustment" in p.511 "Color Registration" for instructions on
how to do this adjustment.
Skew
• If skew occurs immediately after you change the laser unit, do the skew adjustment. (See p.512 "Skew
Adjustment After Laser Unit Replacement").
LD Unit
There is an LD unit for each color, and each LD unit uses a two-beam system. A photo diode (PD) in each
LD unit detects the light emitted from the LD unit. The output of the PD is fed back to the LD control board.
The LD control board uses this information to control the amount of light to make sure that it remains at the
correct level.
Dual Beam Writing
In each LD unit, two beams move across the drum in the main scan direction.
The use of two beams:
• Makes the machine print faster.
• Reduces the number of turns of the polygon mirror for a page to prolong the service life of the motor.
• Reduces the amount motor noise.
The beam pitch is fixed at 600 dpi and is not adjustable.
LD Safety Switches
To ensure the safety of customers and customer engineers, two switches inside the cover prevent the laser
beams from switching on accidentally. When the front cover is open, the +5V line connecting each LD
driver on the LD control board is disconnected.
Laser Unit
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