Epson LQ-670 - For DOS Program Users

Chapter 2
Operating Principles
2.1 Printer Mechanism Operation..............................................................................2-1
2.1.1 Printing Mechanism ............................................................................................................... 2-1
2.1.2 Carriage Mechanism .............................................................................................................. 2-3
2.1.3 Ribbon Advance Mechanism................................................................................................. 2-5
2.1.4 Paper Advance Mechanism...................................................................................................2-6
2.1.4.1 Paper Advance Mechanism ...................................................................................... 2-6
2.1.4.2 Paper Advance Detector Mechanism........................................................................ 2-7
2.1.4.3 Release Lever Mechanism........................................................................................ 2-9
2.1.5 Platen Gap Adjustment ........................................................................................................ 2-10
2.2 Power Supply Operation....................................................................................2-11
2.2.1 Power Supply Circuit ........................................................................................................... 2-11
2.2.1.1 Power Supply Overview............................................................................................2-11
2.2.1.2 Power Supply Circuit Operation .............................................................................. 2-12
2.2.2 Control Circuit ...................................................................................................................... 2-13
2.2.2.1 Operating Principles of the Control Circuit .............................................................. 2-13
2.2.2.2 EEPROM Control Circuit ......................................................................................... 2-14
2.2.2.3 System Reset Circuit............................................................................................... 2-14
2.2.2.4 Power Off Detector Circuit....................................................................................... 2-15
2.2.2.5 Print Head Driver Circuit.......................................................................................... 2-15
2.2.2.6 CR Motor Driver Circuit ........................................................................................... 2-16
2.2.2.7 PF Motor Driver Circuit............................................................................................ 2-16
2.2.2.8 Operation Panel Control Circuit............................................................................... 2-17
2.2.2.9 Interface(I/F) Circuit................................................................................................. 2-18
2.2.2.10 Head Temperature Detector Circuit....................................................................... 2-18
2.2.2.11 Head Drive Voltage Measurement Circuit ............................................................. 2-18
2.2.2.12 Rear and Front Paper End Detector Circuit .......................................................... 2-18
2.2.2.13 Paper Width Detector Circuit................................................................................. 2-18
2.2.2.14 Carriage Home Position (HP) Detector Circuit...................................................... 2-18
2.2.2.15 Release Lever Detector Circuit ............................................................................. 2-18
2.2.2.16 Adjust Lever Detector Circuit................................................................................. 2-18