CANON NP6212
Manual de Servicio

3.

Turning Lamp

On and Off the Scanning

5.

Controlling (automatic) the Fluorescent Lamp Intensity (ALVC control)

Outline When pre-activation pre-heating is over, the microprocessor (QlOl) on the DC controller PCB instructs the microprocessor (Q501) on the composite power supply PCB to generate the scanning lamp on signal (FLAON*). At this time, the fluorescent lamp driver circuit operates to apply the output of the primary side of the main transformer (T102) to both ends of the scanning lamp so as to turn on the scanning lamp at a high frequency. Controlling the Intensity of the Scanning Lamp a. Outline The intensity of the scanning lamp is controlled by the microprocessor (Q501) on the composite power supply PCB. The intensity sensor checks the intensity of the scanning lamp and generates activation power to suit the intensity. The microprocessor, on the other hand, finds out the intensity of the scanning lamp based on the activation power to send the scanning lamp on signal (FLON*) to the on control circuit. Intensity Lower Than the Specified Value The microprocessor increases the duty ratio of the scanning lamp on signal (FLON*) sent to the fluorescent lamp driver. The fluorescent lamp driver, in turn, increases the current flowing to the scanning lamp, thereby increasing the intensity of the scanning lamp. Intensity Higher Than the Specified Value The microprocessor decreases the duty ratio of the scanning lamp on signal (FLON*) sent to the fluorescent lamp driver. The fluorescent lamp driver, in turn, decreases the current flowing to the scanning lamp, thereby decreasing the intensity of the scanning lamp. c. b. 4.

a.

The ,copier executes ALVC control in which the ON voltage of the scanning lamp is automatitally corrected to prevent changes in the copy images caused by deterioration of the photosensitive drum.

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COPYRIGHT 0

1995 CANONINC.

CANON NP6012/NP6012FINP6212SEPT.1995 AEV.I PRlNTEDINJAPAN(IMPAIMiAUJAPON)