Ricoh M199, Техническое учебное пособие

Страница: 54 / 141

54
Process control uses these components:
Central TM (Toner Mark) sensors
Temperature/humidity sensor at the rear right of the machine. This is used to
determine whether the conditions have changed significantly enough so that
process control must be done.
Process control flow
1. TM sensor correction (Vsg adjustment)
The center TM sensor checks the bare transfer belt's reflectivity and
the machine calibrates the TM sensors.
2. Development bias control
The machine makes a 7-gradation pattern on the transfer belt for each
toner color. The pattern has 9 squares (the sequence is as follows: 7
yellow squares, 7 cyan squares, 7 magenta squares and 7 black
squares). Each of the squares is 10 mm x 17 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.
The center TM sensor detects the densities of the 7 solid-color
squares for each color. The machine calculates an appropriate
development bias from this data.
This process takes about 33 seconds to be completed.
3. LD power control
For LD power control, the machine does the same sequence
described in "2 Development bias control". Finally, the machine
calculates an appropriate LD power.
4. MUSIC (Mirror Unit Skew and Interval Control)
The machine uses the TM sensors to measure sample lines deposited
on the ITB, and corrects color image registration adjustment based on
the sensor readings. Sample lines are made on the left, center and