Service manual

PROCESS CONTROL

G130/G131 6-12 SM

Step 5: VD, VB, VL Selection and VREF Adjustment

The machine determines the relationship between the amount of toner on the

transfer belt and the development bias for each of the 10 grades. Then the

machine selects the development bias and charge roller voltages for the target M/A

for each color by referring to a table in memory.

Laser power (VL) selected depends on the setting of SP3-125-2.

• If it is set to "Fixed", the LD power is fixed at the value of SP2-103-1, to -15.

• If it is set to "Process Control", LD power is selected using the same memory

table as mentioned above.

• If it is set to "LD power", LD power is determined by ID sensor highlight pattern

generation (steps 6 to 8 later in this procedure).

The machine also adjusts VREF (toner density target) at the same time so that the

development gamma detected by process control will be the value stored in SP3-

120-1 to -4 (do not adjust in the field unless advised to do so).

NOTE: The patterns on the transfer belt are cleaned by the transfer belt-cleaning

unit.

Allowable changes to VD, VB, and VL (as a result of process control):

This depends on the process control type as follows.

• Forced: No limit

• Initial: After Developer Initialization: ± 80 volts

• Interval: (Job End/ Non-use Time/ During Toner End Recovery): ± 40 volts

• Interval: (Interrupt): Constant (The memory table is not used.)

Steps 6 to 8 are done only if SP3-125-2 is set to "LD Power". (Default: Steps 6

to 8 are not used)

Target

M/A

B Development Bias

Development Bias Charge Bias LD Power

———

B C L

———

Bn-1 Cn-1 Ln-1

Bn Cn Ln

G130D508.WMF