Toshiba e-studio281c, Service Manual, Page: 176 / 414

e-STUDIO281c/351c/451c © 2005 - 2008 TOSHIBA TEC CORPORATION All rights reserved
IMAGE PROCESSING
7 - 4
7.3 SYSTEM CONTROL PC BOARD (SYS)
7.3.1 Features
1) The image processing section on the SYS board is controlled by the CPU on the SYS board.
2) The image processing section on the SYS board realizes the following when functioning the copier:
- 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
3) The image processing section on the SYS board realizes the following when functioning the scanner
and printer:
- Scanner high quality image processing
- Printer high quality image processing
- Black over print (Post Script)
- Pure black / Pure gray (Post Script) / Pure gray (PCL5C)
- Chroma adjustment (PCL5C)
- Brightness adjustment (PCL5C)
7.3.2 Functions of image processing circuit
The image processing section on the SYS board realizes the followings:
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.