Developing Bias Correction; Control Of The Maximum Amount Of Toner Sticking To The Transfer Belt; Laser Light Intensity Correction Control; Gamma Correction Control - Konica Minolta BIZHUB C3100P Service Manual

15.2.2 Developing bias correction

• If the developing bias voltage (Vpp) is excessively high relative to the Ds distance in the imaging unit, a leak image (background leak, image
part leak) occurs. If Vpp is excessively low, faulty halftone reproduction occurs. The Vpp range within which no faulty images occur is
detected to thereby set the proper Vpp.

15.2.3 Control of the maximum amount of toner sticking to the transfer belt

• A simplified detection pattern is produced on the transfer belt and the IDC registration sensor detects the amount of toner sticking to the
pattern.
• The detected data and the environmental data obtained from the temperature/humidity sensor are referenced and the developing bias value
that achieves the proper maximum density is calculated and stored in memory.

15.2.4 Laser light intensity correction control

• This control corrects variations in fine line reproducibility and void reproducibility occurring due to variations (part-to-part, environmental,
durability) in PC drum electrostatic characteristics, developing characteristics, and transfer characteristics to target levels.
• A simplified detection pattern is produced with a predetermined laser light intensity on the transfer belt and the output value from the IDC
registration sensor is detected.
• The laser light intensity is calculated from the detected output data of the IDC registration sensor.

15.2.5 Gamma correction control

• The intensity of LD in all gradation levels is adjusted to correct changes in gradation characteristics to a linear one. The changes in
gradation characteristics are caused by variations in the photo conductor sensitivity and developing characteristics and changes with time
and in environment.
• It produces gradation patterns on the transfer belt and calculates gradation characteristics output by the current engine with the IDC sensor.
• The gamma correction data is calculated using the density measurements of different gradation levels. The optimum LD intensity is set for
each of the different gradation levels.

15.2.6 Color shift correction

• With the tandem engine that has an image forming process for each of different colors, color shift tends to occur due to positional deviations
and variations in parts that restrict the drawing position within the printer.
• The color shift is automatically detected and corrected.

15.3 Control descriptions

15.3.1 Image stabilization type (mode)

• Five different modes of image stabilization are available.
• A specific mode is selected according to the environmental conditions and print requirements, thereby achieving stabilized image at all
times.
Stabilization type
Mode 1 (Full correction control)
Mode 2 (simplified correction control)
Mode 3 (individual registration control)
Mode 4 (1200 dpi mode control)
Mode 5 (monochrome image
stabilization)

15.3.2 Control sequence by mode

• A different control sequence applies according to the mode of image stabilization.
• Control is performed in the specified sequence for each mode.
Sequence Mode 1
IDC sensor output
1
correction
Developing bias
2
correction
Control of the
maximum amount of
3
toner sticking to the
transfer belt
Laser light intensity
4
control
Correction of the
maximum amount of
5
toner sticking to the
transfer belt
Laser light intensity
6
control
All stabilization control items are performed.
All stabilization control items are performed in a simplified manner.
This mode is performed for a maximum period of about 30 sec. when mode 2 is performed.
This mode is performed upon receipt of a 1200-dpi print command; Performed when "1200 dpi" is
performed in image stabilization of the service mode.
All stabilization control items are performed for monochrome.
Mode 2
IDC sensor output IDC sensor output
check
Color shift correction
Developing bias check
(sub-scanning)
Control of the
maximum amount of Color shift correction
toner sticking to the (main scanning)
transfer belt (simplified)
Color shift correction
(sub-scanning)
Laser light intensity
correction (simplified)
Color shift correction
check (main scanning)
O-50
O THEORY OF OPERATION bizhub C3100P > 15. IMAGE
Description
Mode 3 Mode 4
Control of the
maximum amount of
check toner sticking to the
transfer belt (simplified)
Laser light intensity
control
Gamma correction
control
- -
- -
- -
STABILIZATION CONTROL
Mode 5
IDC sensor output
correction
Developing bias
correction
Control of the
maximum amount of
toner sticking to the
transfer belt
Laser light intensity
control
Correction of the
maximum amount of
toner sticking to the
transfer belt
Laser light intensity
control