Canon iR8500 Service Manual page 17

CHAPTER 3 MAIN CONTROLLER
1 Basic Operation .................................. 3-1
1.1 Functional Construction ............ 3-1
1.2 Outline of the Electrical
Circuit ........................................ 3-2
1.2.1 Outline ................................. 3-2
1.2.2 Main Controller PCB ........... 3-2
1.2.3 Hard Disk Drive ................... 3-2
1.3 Start-Up Sequence ..................... 3-4
1.3.1 Outline ................................. 3-4
1.3.2 Start-Up Sequence ............... 3-5
1.3.3 Composition of the System
Software ............................... 3-6
1.4 Inputs to and Outputs from
the Major PCBs .......................... 3-7
1.4.1 Wiring Diagram of
the Major PCBs ................... 3-7
2 Digital image Processing .................... 3-8
2.1 Outline ....................................... 3-8
2.2 Input Image Processing .............. 3-9
2.2.1 Image Data from the Reader
Unit ...................................... 3-9
2.2.2 Enlargement/Reduction
(main scanning direction) .... 3-9
2.2.3 Edge Emphasis .................... 3-9
2.2.4 Editing ................................. 3-9
2.2.5 Density Conversion
(LUT) ................................... 3-9
2.2.6 Binary Processing (error
diffusion method; T-BIC) .... 3-9
2.2.7 Binary Processing
(dither screen method) ....... 3-10
2.3 Controlling the Image
Memory .................................... 3-10
2.3.1 Compression/Expansion,
Rotation, and Enlargement/
Reduction ........................... 3-10
2.3.2 SDRAM ............................. 3-10
2.3.3 HDD .................................. 3-10
COPYRIGHT© 2001 CANON INC. 2000 2000 2000 2000 CANON iR8500/7200 REV.1 AUG. 2001
2.4 Processing Output Image ......... 3-10
2.4.1 Smoothing ......................... 3-10
2.4.2 Thickening
(PDL output only) ............. 3-10
2.4.3 Binary-Binary Density
Conversion (read image
output only) ....................... 3-11
3 Soft Counter ...................................... 3-12
4 Controlling the Power Supply .......... 3-14
4.1 Outline ..................................... 3-14
4.2 Power Supply Mode ................ 3-14
4.3 Standby Mode
(normal operation) ................... 3-14
4.4 Power Save Mode .................... 3-14
4.5 Low-Power Mode .................... 3-15
4.5.1 Shift from Standby Mode
(standby → low-power) ..... 3-15
4.5.2 Shift to standby Mode
(low-power mode
→ standby) ........................ 3-15
4.6 Sleep Mode .............................. 3-15
4.6.1 Shift from Standby Mode
(standby → sleep) .............. 3-15
4.6.2 Shift from Low Power
Mode (low-power mode
→ sleep) ............................. 3-15
4.6.3 Return to Standby Mode
(sleep → standby) .............. 3-15
4.7 Off Mode .................................. 3-16
4.7.1 Shift from Standby Mode
(standby → off mode) ....... 3-16
4.7.2 Shift from Low-Power
Mode (low-power
→ off mode) ...................... 3-16
4.7.3 Return to Standby Mode
(off mode → standby) ....... 3-16
4.8 Power Supply Off Mode .......... 3-16
CONTENTS
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