4 Theory of operation Engine control system ........................................................................................................................ 48 Power-on sequence ........................................................................................................... 49 Motors, fans, and solenoids ............................................................................................... 50 Laser/scanner system ........................................................................................................................
52 Pickup-and-feed-system ..................................................................................................................... 53 Sensors in the pickup-and-feed system trays (cassettes) ................................................. 54 Cassette pickup mechanism .............................................................................................. 55 Multipurpose-tray pickup mechanism ................................................................................ 56 Feed-speed control ............................................................................................................
56 Sensor jam detection ......................................................................................................... 58 Image-formation system ..................................................................................................................... 61 Image-formation process ................................................................................................... 62 Latent-image formation stage ............................................................................................ 63 Step 1: pre-exposure ......................................................................................... 64 Step 2:
primary charging ................................................................................... 64 Step 3: laser-beam exposure ............................................................................ 64 Developing stage ............................................................................................................... 64 Step 4: developing ............................................................................................ 64 Transfer stage .................................................................................................................... 65 Step 5:
media feed ............................................................................................ 65 Step 6: image transfer ....................................................................................... 65 Step 7: separation from the drum ...................................................................... 66 Step 8: separation from the ETB ....................................................................... 66 Fusing stage ...................................................................................................................... 66 Step 9: fusing ....................................................................................................
66 Cleaning stage ................................................................................................................... 67 Step 10: drum cleaning ..................................................................................... 67 Print cartridge .................................................................................................................... 67 Print-cartridge activation .................................................................................................... 68 5 Removal and replacement Removal and replacement strategy ....................................................................................................
70 Introduction ........................................................................................................................ 70 Required tools ................................................................................................................... 71 Types of screws ................................................................................................................. 72 Service approach ............................................................................................................... 73 Before performing service ..................................................................................................
73 After performing service ..................................................................................................... 73 Print cartridges ................................................................................................................... 74 External doors, covers, and panels .................................................................................................... 75 Front cover ......................................................................................................................... 75 Upper cover (fuser door) .................................................................................................... 80 ENWW v