2Nd Transfer Roller Cleaning Control; Toner Density Detection Control; Idc Sensor Calibration Control; Idc Sensor Cover Open/Close Mechanism - Konica Minolta BIZHUB C3100P Service Manual

5. The current temperature inside the main body is detected and backed up.

7.3.4 2nd transfer roller cleaning control

• DC positive and negative transfer bias voltages are alternately applied to the 2nd transfer roller. This allows toner residue on the surface of
the 2nd transfer roller to be transferred back to the transfer belt, thus cleaning the 2nd transfer roller.
• Any voltage for other control purposes is not applied during the cleaning procedure.
• The toner transferred back to the transfer belt is collected by the cleaning blade.
[2]
[3]
[1] 2nd transfer roller
[3] Cleaning blade
(1) Operation timing
• The 2nd transfer roller cleaning sequence is carried out after the transfer belt has been cleaned during recovery from a paperjam or
malfunction.
• If a predetermined number of printed pages or more have been produced after the last cleaning sequence when the printer completes a
print cycle and is then brought to a stop, a new cleaning sequence is carried out before the printer is brought to a stop.
• The cleaning sequence is carried out when a paper size error occurs.

7.3.5 Toner density detection control

• A reflective sensor is used for the IDC sensor that detects the amount of toner sticking to the surface of the transfer belt. Image stabilization
is performed based on the value detected.
• The detection pattern (toner image) produced on the surface of the transfer belt is irradiated with light emitted by the LED of the sensor.
• The photodiode of the sensor detects the light reflected off the toner pattern on the surface of the transfer belt.
[1]
[1] Transfer belt surface
[3] LED
• A voltage corresponding to the intensity of the light reflected off the toner pattern is output to the MFP board.
Amount of toner sticking
Large
Small

7.3.6 IDC sensor calibration control

• Changes in various types of characteristics due to change with time of the IDC sensor (deteriorated LED, dirty sensor surface), part-to-part
variations in the sensors, and change of environment affect the IDC sensor output corresponding to the clear transfer belt surface. To
correct fluctuations in the output, the sensor LED intensity is adjusted so as to keep constant the IDC sensor output value.
• This calibration is executed when an image stabilization sequence is performed.

7.3.7 IDC sensor cover open/close mechanism

• Since the IDC sensor is installed below the transfer belt, it can be dirtied with toner or other foreign matter. A shutter mechanism is therefore
provided above the IDC sensor to prevent it from being dirtied.
• The cover is opened or closed in synchronism with the pressure or retraction motion of the 2nd transfer roller. When the 2nd transfer roller is
released, the cam pushes up the sensor lever, which opens the cover above the IDC sensor.
• When the 2nd transfer roller is pressed, on the other hand, the cover above the IDC sensor is closed by the tension of a spring.
[1]
HV
[2]
[3]
Intensity of light reflected
Small
Great
O-22
O THEORY OF OPERATION bizhub C3100P > 7. 2ND TRANSFER
[2] Transfer belt
- -
[4]
[2] IDC sensor
[4] Photodiode
SECTION
Output
Low
High