Xerox VersaLink B7025 Service Manual page 1300

Process Control: Sensor Checks
Humidity and Temperature Sensor Check
The humidity and temperature sensor checks the temperature and humidity independently.
When the power is ON, the sensor values are continuously monitored to measure the temper-
ature and humidity in the machine. The humidity and temperature sensors are mounted on the
ESS PWB, PL 3.10 Item 6.
ATC Sensor Check
The ATC sensor checks the toner concentration in the drum cartridge while the developer roll is
being driven. The method is as follows:
• The ATC sensor output is read at predetermined intervals.
• The read values, excluding some of the highest and lowest, are averaged.
• The difference between maximum and minimum values is calculated.
• The average read value is corrected to determine the ATC output value (current toner
concentration).
After an ATC sensor check, the ATC target value is calculated. To calculate the ATC target
value, the temperature and humidity correction values calculated from the temperature and
humidity in the machine and the developing material deterioration correction value calculated
from the cumulative drum rotation time are added to the standard ATC target value. Refer to
Figure 19.
Figure 19 ATC sensor
Product Technical Overview
ATC sensor
April 2017
Process Control: Charge Control and Exposure Control
Charge Control
Charge control corrects the charge voltage (the BCR output). Charge control correction factors
include temperature and humidity and the cumulative number of drum rotations. These values
are added to calculate the charge voltage correction value. Charge control occurs at the follow-
ing times:
• At power on
• On return from power save mode
• At the start of a print job
Refer to Figure 20.
Bias charge roller
BCR power
Figure 20 Charge control
8-54 Xerox® VersaLink® B7025/B7030/B7035 Multifunction Printer
HVPS
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