Tcr Sensor Control - Konica Minolta bizhub c450 Service Manual

Theory of Operation Ver. 1.0 Mar. 2005
12.3.6

TCR Sensor control

• The TCR Sensor is mounted on the underside of each of the Developing Sections. The
sensor for C, M, and Y is an optical type, while that for K is a magnetic type. Each of
these sensors detects toner-to-carrier ratio (T/C) of the developer. The reading is used
for determining the amount of toner supplied.
• Only when a new Imaging Unit is installed in the machine, an automatic adjustment is
made of each of these TCR Sensors. The sensors cannot be adjusted manually.
• The target T/C is 8 % both for color and K. This T/C can, however, be changed using
"TCR Level" of "Image Adjust" available from the Tech. Rep. mode.
A. Optical TCR sensor
• A bias is applied to the TCR Sensor window to prevent toner from sticking to it. There is
a magnetic brush provided for the Conveying Screw portion to clean the surface of the
window.
• The sensor portion is separated from the Developing Section (Imaging Unit). When the
TCR Sensor is replaced, it is necessary to replace the Imaging Unit with a new one.
• This represents the fact that the TCR Sensor is adjusted only when a new Imaging Unit
is installed. In addition, if the LPH Unit is to be replaced, it is necessary to remove the
TCR Sensor from the old LPH Unit and mounted it in the new LPH Unit.
B. Magnetic TCR Sensor
• The magnetic permeability (powder density) of the carrier in the developer is measured
to determine the T/C.
• A mylar is provided for the Conveying Screw portion to scrape toner off the surface of the
TCR Sensor.
• The TCR Sensor is integrated with the Imaging Unit. When the TCR Sensor is to be
replaced with a new one, the entire Imaging Unit must be replaced.
TCR Sensor/Y, M, C
Optical TCR Sensor
Magnetic
Brush
TCR
Sensor
Window
4036ma2508c0
TCR Sensor/C, M, Y
(PWB-N1, N2, N3)
4036ma2187c0
12. Developing section
TCR Sensor/K
Magnetic TCR Sensor
Mylar
TCR Sensor/K
4036ma2504c0
4036ma2188c0
37