Ricoh G104, Service Manual

Page: 239 / 601

PROCESS CONTROL
SM 6-11 G104
Detailed
Des
cription
s
6.2.3 PROCESS CONTROL SELF-CHECK PROCEDURE
Step 1: V
SG
Adjustment
This machine uses three ID sensors (direct-reflection type). They are located at the
left, center, and right of the transfer unit. Only the center ID sensor is used for
process control. The ID sensor checks the bare transfer belt's reflectivity and the
machine calibrates the ID sensor until its output (known as V
SG
) is as follows.
•
V
SG
= 4.0
±
0.5 Volts
This calibration adjusts for the transfer belt's condition and the ID sensor condition,
for example, dirt on the belt or ID sensor.
Step 2: ID Sensor Solid Pattern Generation
The machine mixes the developer and then makes a 10-gradation pattern on the
transfer belt for each toner color. The pattern has 10 squares (the sequence is as
follows: 10 black squares, 10 magenta squares, 10 cyan squares and 10 yellow
squares). Each of the squares is 15.03 mm x 12.23 mm, and is a solid-color square.
To make the squares, the machine changes the development bias and charge
roller voltage. The difference between development bias and charge roller voltage
is always the same.
Step 3: Sensor Pattern Detection
The ID sensor detects the densities of the 10 solid-color squares for each color.
This data goes to memory.
Step 4: Toner Amount Calculation
The quantity of toner on the transfer belt (M/A, mass per unit area, mg/cm
2
) is
calculated for each of the 10 gradations of the sensor pattern. To do this, the
machine uses the ID sensor output value from each gradation of the pattern.
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