Image Quality Control - Toshiba e-STUDIO2330C Service Manual

15. IMAGE QUALITY CONTROL

15.1 General Description
In this equipment, image quality is controlled by the image quality sensor (S18). At this control, image
forming conditions are automatically adjusted so as to minimize the change in the image density or tone
reproduction caused by the fluctuation of working environment or life of supply items.
At first, the image quality sensor (S18) operates to output reflected light amount voltage when no toner
image is formed on the transfer belt. The output voltage is then converted analog-to-digital to be output
as the reflected light amount signal. The light source amount voltage of the sensor is adjusted to
correspond with the value set in advance and the output value of reflected light amount signal at this
adjustment is stored. This output value is considered as the reading of the belt surface. Next, the
sensor outputs the reflected light amount signal when a test pattern is developed on the transfer belt.
This output value is considered as the reading of the toner image.
The difference between the reading of the transfer belt and that of the toner image is defined as toner
adhesion amount. Image forming conditions are determined in approximating this toner adhesion
amount to the value set in advance.
In addition, a shutter operated by the sensor shutter solenoid (SOL2) is equipped on the light receiving/
emitting surfaces to prevent stain to the sensor.
Image quality control unit
Image position aligning sensor ( rear )
Sensor shutter solenoid
Image quality sensor
Image position aligning sensor ( front )
Fig. 15-1
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IMAGE QUALITY CONTROL
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