Sharp MX-2314N Service Manual page 448

Black image density sensor (image registration R) sensitivity
adjustment operation
When the machine enters the adjustment operation, the primary
transfer unit enters the print mode to perform the sensor sensitivity
adjustment by using the surface reflection of the primary transfer
belt.
The adjustment operation means the operation which seeks for the
LED current to obtain the specified output level pf the sensor.
b. High density process control operation (Toner patch generation and density correction operations)
1) When the machine enters the high density process control mode, the secondary transfer unit enters the free state.
2) While changing the DV bias voltage step by step, a number of toner patches in different densities are generated on the F side and the R
side of the primary transfer belt.
F side: The color toner patch is generated.
R side: The black toner patch is generated.
3) Each toner patch density is detected by the image density sensor, and the DV bias correction voltage is calculated in the PCU PWB so that
the proper density is obtained from the relation between the DV bias voltage at the time when each toner patch is made and the toner
patch density.
MX-3114N OPERATIONAL DESCRIPTIONS 13 – 28