Toshiba e-STUDIO2500c, Service Manual, Page: 162 / 402

e-STUDIO2500c/3500c/3510c IMAGE PROCESSING May 2006 © TOSHIBA TEC
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7.3 IMAGE PROCESSING PC BOARD (IMG)
7.3.1 Features
1) The image processing section is controlled by the CPU on the IMG board.
2) The image processing PC board realizes the following functions:
- ACS
- Color conversion (CMY image data processing)
- Black component generation
- High quality image processing
- Image memory editing
- Rectangular area signal generation
- Editing processing
- Gamma correction
- Gradation processing
- Compression/expansion
- Scanner high quality image processing
- Printer high quality image processing
7.3.2 Functions of image processing circuit
1) ACS (Auto Color Selection)
This function determines whether the original to be scanned is colored or monochrome, based on
the analysis of the R, G and B signals output from the CCD.
2) Color conversion (CMY image data processing)
When functioning the copier, the RGB image data is converted to CMY image data. (When function-
ing the scanner, it is converted to RGB image data.)
The image data taken in by the scanner represents the intensities of reflection from the three pri-
mary colors of light (Red, Green and Blue). These RGB values are then color-converted to the
respective amounts of toners corresponding to the three colors (Yellow, Magenta and Cyan) for
printing (=CMY image data processing).
3) Black component generation
K (Black) signal is generated from the CMY image data. Based on this K signal, the CMY image
data is corrected to suppress hue on reproducing grays or to make the black look more real.
4) High quality image processing
- Background processing function
By using the background adjustment function while manually adjusting the image density, unde-
sirable background of the original can be removed if any, and some necessary but disappeared
background can be recovered. By using this function, it is possible to cut the background density
down when copying originals which have a certain level of background density, such as newspa-
pers.