Ricoh B264 Service Manual page 19

6.4.2 SCANNER DRIVE ..........................................................................6-14
Book Mode..........................................................................................6-14
ADF mode...........................................................................................6-14
6.4.3 ORIGINAL SIZE DETECTION IN PLATEN MODE.........................6-15
6.5 IMAGE PROCESSING ............................................................................6-17
6.5.1 OVERVIEW ....................................................................................6-17
6.5.2 SBU (SENSOR BOARD UNIT).......................................................6-18
6.5.3 AUTO IMAGE DENSITY (ADS) ......................................................6-19
6.5.4 IPU (IMAGE PROCESSING UNIT).................................................6-20
Overview.............................................................................................6-20
6.5.5 IMAGE PROCESSING MODES .....................................................6-21
6.5.6 SUMMARY OF IMAGE PROCESSING FUNCTIONS ....................6-23
6.5.7 IMAGE PROCESSING STEPS AND RELATED SP MODES.........6-24
Text Mode...........................................................................................6-24
Text/Photo Mode ................................................................................6-25
Photo Mode ........................................................................................6-26
Pale (Low-Density Mode)....................................................................6-27
Generation Copy Mode.......................................................................6-28
6.5.8 PRE-FILTERING ............................................................................6-29
6.5.9 BACKGROUND ERASE.................................................................6-30
6.5.10 INDEPENDENT DOT ERASE ......................................................6-31
6.5.11 LINE WIDTH CORRECTION........................................................6-32
6.5.12 FILTERING ...................................................................................6-33
Interactive SP Codes ..........................................................................6-33
Text Mode MTF Filter..........................................................................6-38
Text/Photo, Photo Mode Filter ............................................................6-39
Pale, Generation Mode Filter ..............................................................6-40
Photo Mode Smoothing for Dithering ..................................................6-41
Photo Mode Grayscale .......................................................................6-41
Photo Mode Image Quality .................................................................6-42
6.5.13 OTHERS.......................................................................................6-43
Vertical Black Line Correction.............................................................6-43
Density Settings ..................................................................................6-43
ADS Level...........................................................................................6-44
6.5.14 PRACTICAL APPLICATION OF SP MODES ...............................6-45
Solving Problems ................................................................................6-45
Recommended Settings for MTF Filters .............................................6-46
6.6 LASER EXPOSURE................................................................................6-48
6.6.1 OVERVIEW ....................................................................................6-48
6.6.2 AUTO POWER CONTROL (APC) ..................................................6-49
6.6.3 DUAL BEAM WRITING ..................................................................6-50
6.6.4 LASER BEAM PITCH CHANGE MECHANISM ..............................6-51
6.6.5 LD SAFETY SWITCHES ................................................................6-52
6.7 PHOTOCONDUCTOR UNIT (PCU) ........................................................6-53
6.7.1 OVERVIEW ....................................................................................6-53
6.7.2 DRUM CLEANING..........................................................................6-54
6.7.3 DRIVE MECHANISM......................................................................6-55
6.7.4 DRUM PAWLS ...............................................................................6-55
6.7.5 DRUM TONER SEALS...................................................................6-55
SM vii B264/B265