Ricoh LD013, Service Manual

Page: 230 / 513

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DRUM CHARGE
SM 6-37 B039/B040/B043
If the humidity drops, the drum potential goes up (to a higher –ve voltage) even if
the charge roller voltage supply stays the same (efficiency of voltage transfer is
higher with lower humidity). As a result, less toner is transferred to ID sensor
pattern [B]. If the sensor output reaches a certain point, the drum charge voltage
will be reduced.
To determine whether to change the drum charge roller voltage, the machine
compares Vsdp with Vsg.
•
Vsdp/Vsg > 0.95 = Make the drum charge voltage less –ve (smaller) by 50 V
•
Vsdp/Vsg < 0.90 = Make the drum charge voltage more –ve (larger) by 50 V
6.8.3 ID SENSOR PATTERN PRODUCTION TIMING
The ID sensor pattern is not made every page or every job.
It is only made in the following conditions:
•
During warm-up at power on
•
If the machine starts warming up after a certain time (default: 90 minutes) has
passed since entering night/off mode or low power mode.
The 90-minute interval can be changed using SP2-995.