Image Quality Control; General Description - Toshiba e-STUDIO281c Service Manual

15. IMAGE QUALITY CONTROL

15.1 General Description

In this equipment, image quality is controlled by the image quality sensor (S17). 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 (S17) 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 corre-
spond with the value set in advance and the output value of reflected light amount signal at this adjust-
ment 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 out-
put 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 solenoid is equipped on the light receiving/emitting surfaces to
prevent stain to the sensor and to calibrate the sensor with the reflection from the shutter.
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June 2005 © TOSHIBA TEC e-STUDIO281c/351c/451c IMAGE QUALITY CONTROL
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