Image Quality Control - Toshiba e-STUDIO 5540C Service Manual

3.14 Image Quality Control

Image quality control is divided into image quality process control and image quality TRC control. When
the e-BRIDGE Controller is installed, the image quality TRC control is performed with a single test
pattern, and when the EFI Printer Board (optional) is installed, it is performed with 2 test patterns.
3.14.1 General Description
In this equipment, image quality is controlled with the image quality sensor (S23).
In the image quality control, image forming conditions or image processing conditions are automatically
adjusted so as to minimize the change in the image density or tone reproduction caused by the
fluctuation of the use environment or the life of the supply items.
At first, the image quality sensor (S23) emits light in order to output the reflected light amount voltage
with no toner image formed on the transfer belt.
This reflected light amount voltage is then converted analog-to-digital to be output to the LGC board as
a reflected light amount signal. The light amount voltage of the light source of the sensor is adjusted so
that the output value of the reflected light amount signal will correspond with a value set in advance.
Next, a test pattern is developed on the transfer belt, and the reflected light amount signal output from
the developed test pattern is detected as the toner amount for a toner image. This series of operations
is the scanning of a toner image (detection of the output value).
3 test patterns are provided for scanning this toner image. Each of them is used to determine the
following conditions:
1. Image quality process control test pattern
The toner image of the test pattern is scanned and the image forming conditions are determined to
be approximated to the preset value.
2. Image quality TRC control test pattern
The toner image of the test pattern is scanned and the image processing conditions are determined
according to the value output from the toner image.
3. Image quality TRC control test pattern for the EFI Printer Board (optional)
(Only for the equipment with the EFI Printer Board (optional) installed.)
The toner image of the test pattern is scanned and the image processing conditions are determined
according to the value output from the toner image.
In addition, a shutter operated by the Image quality shutter solenoid (SOL3) is equipped on the light
receiving/emitting surfaces to prevent stain to the sensor.
Image quality sensor
© 2011 - 2015 TOSHIBA TEC CORPORATION All rights reserved
Image position aligning sensor (rear)
Image quality shutter solenoid
Image position aligning sensor (center)
Image position aligning sensor (front)
Fig. 3-52
3 - 91
Image quality control unit
e-STUDIO5540C/6540C/6550C/5560C/6560C/6570C
OUTLINE OF THE MACHINE
3