August 2006 PROCESS CONTROL
6-87
Detailed
Descriptions
6.11.4 TONER SUPPLY CONTROL
Overview
The toner supply method can be selected with SP3301 001-004.
• 0: Fixed supply mode (used for testing only; do not use this mode except
during some troubleshooting procedures as described in section 4)
• 1: PID (Proportional Integral Differentiation) control mode (default)
This section describes only PID control because only PID control is used in the
field.
PID control uses inputs from pixel count, and from the TD and ID sensors. If the TD
or ID sensor is broken, the machine uses PID control with inputs from pixel count
only.
The following three functions comprise toner supply control for this machine.
1. At the end of every job (at the same time as potential control)
This is done if the number of pages since the previous toner supply control is more
than the number that is set with SP 3551.
Black-and-white After 250 pages (adjustable with SP3551 001)
Full color After 200 pages (adjustable with SP3551 002)
Using the development gamma that was calculated during potential control, the
machine determines the target amount of toner (M/A: Mass per Area):
• Low development gamma: Raises the target image density of the sensor
pattern and increases the toner concentration.
• High development gamma: Lowers the target image density of the sensor
pattern and decreases the toner concentration.