Ricoh FT4460, Service Manual, Page: 81 / 413

28 February 1989
4.3 ERASE TIMING
Operation Timing
T0: Start key ON. All erase lamps turn on, bias is applied.
T1: T1 = T0 + 0.1 sec. Change corona outputs ID sensor grid voltage for
0.49 seconds.
T2:
T3:
T4:
T5:
T 2 =
T0 + 0.63 sec. Some erase lamps switcn off to create the ID
sensor pattern. Also, the development bias is changed to match the ID
sensor pattern. For color, this happens at T0 + 0.65. For black, this
happens at T0 + 0.9 seconds.
T3 = T0 + 0.81 sec. The erase lamps which were switched off turn on
again, and there is full erase until T0 + 0.94 seconds. In order to create
the Vr pattern, bias is reduced to 0V at T0 + 1.02 sec.
T4 = T0 + 1.14 sec. The ID sensor pattern bias switches to image bias.
For color, at T0 + 1.14 + T4. For black, at T0 + 1.4. Vr pattern check is
performed, the 0V bias rises to ID sensor pattern bias at T0 + 1.33 sec.
T5 = T0 + 1.88 sec. The ID sensor pattern is checked to correct the
image density level or the VR pattern is checked to compensate for
residual voltage on the drum.
2-28