Canon LBP-1210 Service Manual page 99

4) Fixing bias generation
The fixing bias prevents toner from adhering to the fixing film. This bias is generated by divid-
ing the primary charging DC bias. At the timing of primary charging DC bias application to the
primary charging roller, the bias is applied to the fixing film through the pressure roller.
5) Cartridge detection
Cartridge presence is detected by the CPU checking the voltage of the CARTRIDGE DETECTION
(CRGSNS) signal, a feedback signal of the primary charging AC bias.
To feedback the CRGSNS signal to the CPU, the primary charging bias circuit detects the volt-
age level of the primary charging AC bias applied to the primary charging roller. This is imple-
mented when the PRIMARY CHARGING AC BIAS DRIVE (PRACC) signal is output from the CPU
and also the primary charging AC bias is output from the AC generation circuit in the primary
charging bias circuit.
The CPU checks the voltage level of the CRGSNS signal at the timing of primary charging AC
bias output during the WAIT period, and thus detects the cartridge presence.
CHAPTER 2
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