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Phaser 440 Color Printer
5
Theory of Operation
Print engine 5-2
Sublimation dye transfer — the engine's printing technology 5-2
The print process 5-2
Continuous-tone printing 5-3
Image data 5-4
Creating colors 5-4
Engine control board block description 5-5
CPU 5-6
Interface buffers 5-6
Data controller and line buffers 5-6
Heat controller (dot compensation) 5-6
Thermal head controller 5-7
Thermal head 5-7
Mechanical controller 5-7
Internal test pattern generator 5-7
Paper path in operation 5-8
Paper pick-up 5-8
Drum loading 5-10
Printing 5-12
Print unloading 5-13
Power supply 5-14
Image processor 5-16
Image rendering technology 5-16
6
Troubleshooting
System power-up sequence 6-1
Print engine troubleshooting 6-2
Verifying image processor operation by using the Test Pattern Generator 6-2
Verifying print engine operation by using its self-test print 6-3
Verifying power supply operation 6-3
Measuring power supply voltages 6-3
Inspecting the power supply fuses 6-5
Testing for a shorted motor 6-6
+24 VDC safety interlocks 6-6
Testing motor resistances 6-8
