AcuLaser C2800/C2800D/C3800/C3800D Revision C
OPERATING PRINCIPLES Control 63
Confidential
2.7.3.2 Toner Density Control
To acquire stabilized print images, toner density should be kept constant. The control
to keep the toner density constant is called “toner density control”.
1. PCDC (Pixel Count Dispense Control)
Calculates the amount of toner to be used in the developing process by counting
the video signals that are input to the ROS ASSY. The amount of consumed toner
is calculated as toner dispense time. Refilling toner as much as the consumed
amount can be made by driving the corresponding Toner Motor(s) in the
DISPENSER ASSY for the calculated period of time (toner dispense time).
2. ADC (Auto Density Control)
Creates four patches (yellow, magenta, cyan, and black) on the Transfer Belt under
the given electrical conditions, and measures their density with the ADC Sensor.
The measured density is compared with the reference one, and the toner dispense
time is increased/decreased in subsequent print process when the measured density
is lower/higher than the reference density. The amount of toner to be refilled is
calculated as toner dispense time. This is calculated for each of the four colors.
2.7.3.3 High Area Coverage Mode
The Toner Dispense control cannot keep up with heavy consumption of toner, such as
printing pages with high print ratio continuously, and leads to lower the toner density.
High Area Coverage Mode is provided to resolve the problem. In this mode, if the
Dispense Count reaches to a certain level during performing continuous printing,
feeding the next paper is temporarily stopped to perform the toner dispense.
2.7.3.4 Admix Mode
When ADC Sensor detects that the toner density is too low compared to predetermined
level by reading the toner patch, toner dispense is carried out to increase the density. If
this operation cannot restore the toner density, it is detected that the toner has run out.
2.7.3.5 ADC Sensor Adjustment
ADC Sensor is a reflective density sensor. It irradiates the target with the light emitted
from the LED in the sensor, detects the light reflected from the target with a light
receiving element, and outputs the electrical signal in accordance with the light
intensity. When creating toner patch for controlling electrical potential and toner
density, ADC Sensor surface is cleaned to remove dirt such as toner and the light
intensity is adjusted so that the amount of reflected light becomes predetermined level
in order to read the patch density accurately.
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