Epson 2070 - LQ B/W Dot-matrix Printer Service Manual page 48

List of Figures
Figure 2-1. Principles of Printhead Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Figure 2-2. Carriage Movement Mechanism. . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Figure 2-3. Platen Gap Adjust Lever . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Figure 2-4. Release Sensor Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Figure 2-5. Friction Advance Operation Using the Top Entrance . . . . . . . . . . . . 2-5
Figure 2-6. Push Tractor Operation Using the Rear Paper Entrance . . . . . . . . . 2-6
Figure 2-7. Push Tractor Operation Using the Front Paper Entrance. . . . . . . . . 2-7
Figure 2-8. Pull Tractor Operation Using the Bottom Paper Entrance . . . . . . . . 2-8
Figure 2-9. Push- Pull Tractor Operation Using the Rear Paper Entrance . . . . . 2-9
Figure 2-10. Push- Pull Tractor Operation Using the Front Paper Entrance . . 2-10
Figure 2-11. Paper Path and Detector PE Sensor Location . . . . . . . . . . . . . . . 2-11
Figure 2-12. Friction Feeding Using the Top Entrance . . . . . . . . . . . . . . . . . . . 2-11
Figure 2-13. Push Tractor Feeding Using the Rear Entrance. . . . . . . . . . . . . . 2-12
Figure 2-14. Pull Tractor Feeding Using the Rear Entrance . . . . . . . . . . . . . . . 2-12
Figure 2-15. Push-Pull Tractor Feeding Using the Rear Entrance . . . . . . . . . . 2-13
Figure 2-16. Pull Tractor Feeding Using the Bottom Entrance . . . . . . . . . . . . . 2-13
Figure 2-17. Friction Feeding Using the Front Entrance . . . . . . . . . . . . . . . . . . 2-14
Figure 2-18. Push Tractor Feeding Using the Front Entrance . . . . . . . . . . . . . 2-14
Figure 2-19. Pull Tractor Feeding Using the Front Entrance . . . . . . . . . . . . . . 2-15
Figure 2-20. Push-Pull Tractor Feeding Using the Front Entrance. . . . . . . . . . 2-15
Figure 2-21. Ribbon Advance Mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16
Figure 2-22. Power Supply Circuit Block Diagram . . . . . . . . . . . . . . . . . . . . . . 2-17
Figure 2-23 Power Switch Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-18
Figure 2-24. Over Voltage Protection Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . 2-18
Figure 2-25. +35 V Line Constant Voltage Control Circuit . . . . . . . . . . . . . . . . 2-19
Figure 2-26. +35 V Line Overload Detector Circuit . . . . . . . . . . . . . . . . . . . . . . 2-19
Figure 2-27. +35 V Line Over Current Protection Circuit . . . . . . . . . . . . . . . . . 2-20
Figure 2-28. +5 V Line Over Current Protection Circuit . . . . . . . . . . . . . . . . . . 2-20
Figure 2-29. +5 V Constant Voltage Control Circuit . . . . . . . . . . . . . . . . . . . . . 2-21
Figure 2-30. Control Circuit Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22
Figure 2-31. Data Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23
Figure 2-32. Reset Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24
Figure 2-33. Reset Signal Output Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24
Figure 2-34. Printhead Driver Circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24
Figure 2-35. CR Driver Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-25
Figure 2-36. PF Motor Driver Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-26
Figure 2-37. EEPROM Control Circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-26
Figure 2-38. Sensor Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-27
List of Tables
Table 2-1. CR Motor Assembly Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Table 2-2. Platen Gap and Print Speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Table 2-3. Release Lever Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Table 2-4. Ribbon Advance Gear Linkage . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16
Table 2-5. Power Supply Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-17
Table 2-6. Power Supply Output Voltage and Applications . . . . . . . . . . . . . . . 2-17
Table 2-7. Functions of the Main IC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23
Table 2-8. CR Motor Driver Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-25