Ricoh A250 - A250;B001 Service Manual

SM i A250
TABLE OF CONTENTS
OVERALL INFORMATION
1. OVERALL MACHINE INFORMATION ........................................1-1
1.1 SPECIFICATIONS.................................................................................... 1-1
1.2 MACHINE CONFIGURATION .................................................................. 1-5
1.3 PAPER PATH........................................................................................... 1-6
1.4 MECHANICAL COMPONENT LAYOUT................................................... 1-7
1.5 ELECTRICAL COMPONENT DESCRIPTIONS........................................ 1-8
1.5.1 COPIER ENGINE ............................................................................ 1-8
1.6 DRIVE LAYOUT...................................................................................... 1-11
1.7 COPY PROCESS................................................................................... 1-12
1.7.1 OVERVIEW.................................................................................... 1-12
1.8 BOARD STRUCTURE............................................................................ 1-14
1.8.1 OVERVIEW.................................................................................... 1-14
1.8.2 DESCRIPTION .................................................................................... 1-15
DETAILED DESCRIPTIONS
2. DETAILED SECTION DESCRIPTIONS.......................................2-1
2.1 SCANNING............................................................................................... 2-1
2.1.1 OVERVIEW...................................................................................... 2-1
2.1.2 SCANNER DRIVE ........................................................................... 2-2
2.1.3 ORIGINAL SIZE DETECTION IN PLATEN MODE.......................... 2-3
2.2 IMAGE PROCESSING ............................................................................. 2-5
2.2.1 OVERVIEW...................................................................................... 2-5
2.2.2 SBU (SENSOR BOARD UNIT)........................................................ 2-7
2.2.3 AUTO IMAGE DENSITY (ADS) ....................................................... 2-8
2.2.4 IMAGE PROCESSING UNIT (IPU).................................................. 2-9
2.2.5 MEMORY CONTROLLER AND EXTENDED MEMORY
BOARD (EMB)............................................................................... 2-20
2.2.6 VIDEO CONTROL UNIT (VCU)..................................................... 2-21
2.2.7 IMAGE PROCESSING SUMMARY ............................................... 2-23
2.3 LASER EXPOSURE ............................................................................... 2-33
2.3.1 OVERVIEW.................................................................................... 2-33
2.3.2 OPTICAL PATH............................................................................. 2-34
2.3.3 AUTO POWER CONTROL (APC) ................................................. 2-35
2.3.4 LD SAFETY SWITCH .................................................................... 2-36
2.4 ALL-IN-ONE CARTRIDGE (AIO CARTRIDGE)...................................... 2-37
2.4.1 OVERVIEW.................................................................................... 2-37
2.4.2 DRIVE............................................................................................ 2-38
2.4.3 DRUM CHARGE............................................................................ 2-39
2.4.4 DEVELOPMENT............................................................................ 2-40
2.4.5 DRUM CLEANING......................................................................... 2-43