Ricoh B082 Service Manual page 19

6.5.3 AUTO IMAGE DENSITY (ADS).......................................................6-18
6.5.4 IPU (IMAGE PROCESSING UNIT) .................................................6-19
Overview .............................................................................................6-19
6.5.5 IMAGE PROCESSING MODES ......................................................6-20
6.5.6 SUMMARY OF IMAGE PROCESSING FUNCTIONS .....................6-22
6.5.7 IMAGE PROCESSING STEPS AND RELATED SP MODES..........6-23
Text Mode ...........................................................................................6-23
Text/Photo Mode.................................................................................6-24
Photo Mode.........................................................................................6-25
Pale (Low-Density Mode)....................................................................6-26
Generation Copy Mode.......................................................................6-27
6.5.8 PRE-FILTERING .............................................................................6-28
6.5.9 BACKGROUND ERASE..................................................................6-29
6.5.10 INDEPENDENT DOT ERASE .......................................................6-30
6.5.11 LINE WIDTH CORRECTION .........................................................6-31
6.5.12 FILTERING ....................................................................................6-32
Interactive SP Codes ..........................................................................6-32
Text Mode MTF Filter..........................................................................6-36
Text/Photo, Photo Mode Filter ............................................................6-37
Pale, Generation Mode Filter ..............................................................6-38
Photo Mode Smoothing for Dithering ..................................................6-39
Photo Mode Grayscale .......................................................................6-39
Photo Mode Image Quality .................................................................6-40
6.5.13 OTHERS........................................................................................6-41
Vertical Black Line Correction .............................................................6-41
Density Settings ..................................................................................6-42
ADS Level ...........................................................................................6-43
6.5.14 PRACTICAL APPLICATION OF SP MODES ................................6-44
Solving Problems ................................................................................6-44
Recommended Settings for MTF Filters .............................................6-45
6.6 PHOTOCONDUCTOR UNIT (PCU) .........................................................6-47
6.6.1 OVERVIEW .....................................................................................6-47
6.6.2 DRIVE MECHANISM.......................................................................6-48
6.6.3 DRUM PAWLS ................................................................................6-48
6.6.4 DRUM TONER SEALS....................................................................6-48
6.6.5 DRUM CLEANING ..........................................................................6-49
6.7 DRUM CHARGE.......................................................................................6-50
6.7.1 OVERVIEW .....................................................................................6-50
6.7.2 CHARGE ROLLER VOLTAGE CORRECTION ...............................6-51
Correction for Environmental Conditions ............................................6-51
6.7.3 ID SENSOR PATTERN PRODUCTION TIMING.............................6-52
6.7.4 DRUM CHARGE ROLLER CLEANING ...........................................6-52
6.7.5 CORRECTION FOR PAPER WIDTH AND THICKNESS ................6-53
6.7.6 DEVELOPMENT BIAS ....................................................................6-54
Mechanism .........................................................................................6-54
Correction for paper width and thickness (by-pass tray only)..............6-54
6.8 DEVELOPMENT ......................................................................................6-55
6.8.1 OVERVIEW .....................................................................................6-55
6.8.2 DRIVE MECHANISM.......................................................................6-56
SM vii B079/B082