Aidc Sensor Led Intensity Control; Background Margin Control; Max. Density Control; Correction Control - Minolta CF1501 Service Manual

(1)

AIDC Sensor LED Intensity Control

• Controls changes in characteristics due to change with time and contamination of the
AIDC Sensor, and part-to-part variations in the sensors, and change of environment.
1. Adjusts the intensity (current value) of the LED on the surface of the Transfer Belt, on
which no toner sticks.
(2)

Background Margin Control

• Corrects changes in charging efficiency as a result of a deteriorated PC Drum and envi-
ronmental condition changes.
• Controls the PC Drum Charge Corona grid voltage so that the background margin
becomes 100 V.
1. Determines the PC Drum Charge Corona grid voltage based on the information pro-
vided by various sensors, system speed, and the target surface potential.
Target surface potential V0 (V) = Required developing bias voltage Vb (V) - 100 V
(3)

Max. Density Control

• Adjusts the developing bias (Vb) to control changes in the solid density resulting from
variations in developing characteristics and LED intensity, variations in sensitivity of the
PC Drum, and changes in the environment, durability, and the amount of charge in toner.
1. Produces patterns on the surface of the Transfer Belt and lets the AIDC Sensor detect
the amount of toner sticking to them.
2. Selects the correction data appropriate for each color based on the correction data
with four different levels for each color.
3. Computes from the detected data the developing bias and grid voltage values that
result in the maximum density and stores the values in memory.
γ Correction Control
(4)
• Adjusts the LED intensity to correct changes in gradation characteristics to a linear one.
The changes in gradation characteristics are caused by variations in the PC Drum sensi-
tivity and developing characteristics and changes with time and in environment.
1. Produces patterns on the surface of the Transfer Belt and lets the AIDC Sensor detect
the amount of toner sticking to them.
2. According to the density measurements of different gradation levels, γ correction data
is computed and the optimum LED intensity is set for each gradation level.
Control Provided:
Control Provided:
Control Provided:
Control Provided:
M-14