Laser Beam Pitch Change Mechanism - Ricoh G147 Service Manual

The two laser beams arrive on the drum surface about 2 mm apart in the main scan direction
and about 0.06 mm apart (at 400 dpi) in the sub scan direction. The two-mm difference in
the main scan direction allows the machine to detect the laser synchronization signal for
each beam.

6.4.4 LASER BEAM PITCH CHANGE MECHANISM

When the LD positioning motor [A] turns, the metal block [B] in contact with the LD unit
housing [C] moves up and down and changes the position of L2 (L1 does not move).
Both LD unit positions are at fixed distances from the LD unit home position sensor [D].
Usually, the LD unit moves directly to the proper position. However, when the number of
times that the resolution has changed reaches the value of SP2109 05, the LD unit moves to
the home position, and this re-calibrates the LD unit positioning mechanism.
G147 6-14 SM