Oce 3121, Техническое и сервисное руководство

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504 TSM Océ 3121 Functional description
3 Controlling the bias for the transfer roller
The bias for the transfer roller is controlled by the CPU (Q605) on the power
supply PBA. This is according to instructions from the DC control PBA .
Switching of the application of bias
The bias types are switched, based on combinations of the transfer output
mode 0 (HVTM0) and the transfer output mode 1 (HVTM1) from the DC con-
trol PBA .
Switching ON and OFF the Cleaning Bias
When the cleaning bias drive signal is ‘1’ (TREVON from the power supply
PBA), the secondary side of the main transformer (T101) is switched on. This
applies a cleaning bias (negative) to the transfer roller.
The timing of the application of the cleaning bias is determined by serial com-
munication data, exchanged with the DC control PBA .
Switching the transfer roller ON and OFF
The bias for the transfer roller bias is switched ON and OFF by the transfer
bias control signal (TFWPWM) and the transfer bias ON signal (TFWON).
When the TFWON signal is ‘0’, the transformer T502 switches ON.
HVTM0 HVTM1 Bias type
0 0 Cleaning bias
1 0 Transfer bias
0 1 Reference bias
1 1 Sheet-to-sheet bias