Epson 670 2.1.4.2 Paper Advance Detector Mechanism

LQ-670 Service Manual

Rev. A 2-

7

2.1.4.2 Paper Advance Detector Mechanism

Paper advance detector mechanism consists of PW detector and PE (rear/front) detectors.

The function of this mechanism is to feedback information about monitoring paper edges , paper width and

paper jam, and to control paper advance. The detector’s reading operation is constantly performed. The

timing to feedback the red signals is necessarily selected by CPU according to the operation of PF motor

and CR motor. The table below shows specification of the detectors and their functions.

Detectors Operation Function

PW detector Paper width measurement (detects

right and left edges) Determ ines right and left margin

Paper top edge detector(detects

top and bottom edges) Determines top and bottom margin

Detects if there is any paper or not Detects paper jam after checking

paper loading and ejecting.

PE detectors (Rear/Front) Detects top and bottom margin Determines top and bottom margin

Detects if there is any paper or not Detects paper jam and paper out (if

PW detector does not detect the

paper out) after checking paper

loading and ejecting.

Front paper detector only Detects paper top margin Front entry in case of c ut sheet

auto feed

Print Head

CR Motor Mask Guide

Platen

Print Head

TOP Detector

Mask Guide

Roller Assembly, Paper Eject,

Drive

Front PE Detector

Roller Assembly, PF, Support

Rear PE Detector

Looking from

the front face.

Looking from

the top.

TOP Detector

Figure 2-5. Paper Advance Detector Mechanism

Table 2-5. Detector Function and Operation

Contents

Main NOTICE Copyright 1997 by SEIKO EPSON CORPORATION Nagano, Japan PRECAUTIONS WARNING CAUTION WARNING CAUTION PREFACE Page Page Chapter 1 Product Descriptions 1.1 Specifications 1.1.1 Features Page 1.2 Hardware Specifications 1.2.1 Printing Method 1.2.2 Printing Specifications Rev. A 1- 1.2.3 Paper Handling Specifications 1.2.4 Paper Specification Rev. A 1- Note1) Note3): Note2): Note2): Page Page 1.2.5 Printable Area Rev. A 1-11 Note *1) Printable Area Printable Area BM 1.2.6 Ribbon Cartridge 1.2.7 Input data buffer Note*) 1.2.8 Electrical Specification 1.2.9 Reliability 1.2.10 Environmental Condition 1.2.11 Safety Approvals 1.2.12 CE Marking 1.2.13 Acoustic Noise 1.3 Firmware Specification 1.3.1 Control Codes and Fonts Page 1.3.2 Interface Specification 1.3.2.1 Parallel interface (Forward channel) Page 1.3.2.2 Parallel Interface (Reverse channel) Note*): Rev. A 1-21 1.3.2.3 Optional Interface 1.3.2.4 Interface Selection 1.3.3 Prevention Hosts from Data Transfer Timeout 1.4 Operation 1.4.1 Control Panel 1.4.1.1 Usual Operation Page 1.4.1.2 Switches 1.4.1.3 Indicators(LED) 1.4.1.4 Buzzer 1.4.2 Default Setting Notes. 1.4.3 Bi-d Adjustment 1.4.4 Initialization 1.4.5 Errors 1-3 1.5 Main Components 1.5.1 C214 Main Board 1.5.2 C214PSB Board Page Chapter 2 Operating Principles Rev. A 2-1 2.1 Printer Mechanism Operation 2.1.1 Printing Mechanism Page 2.1.2 Carriage Mechanism Page 2.1.3 Ribbon Advance Mechanism 2- 2.1.4 Paper Advance Mechanism 2.1.4.1 Paper Advance Mechanism 2.1.4.2 Paper Advance Detector Mechanism Page 2.1.4.3 Release Lever Mechanism Release Lever Tractor Gear Roller, PF Drive Tractor Transmission Gear 2.1.5 Platen Gap Adjustment Rev. A 2-11 2.2 Power Supply Operation 2.2.1 Power Supply Circuit 2.2.1.1 Power Supply Overview 2.2.1.2 Power Supply Circuit Operation Rev. A 2-1 2.2.2 Control Circuit 2.2.2.1 Operating Principles of the Control Circuit 2.2.2.2 EEPROM Control Circuit 2.2.2.3 System Reset Circuit 2.2.2.4 Power Off Detector Circuit 2.2.2.5 Print Head Driver Circuit 2.2.2.6 CR Motor Driver Circuit 2.2.2.7 PF Motor Driver Circuit 2.2.2.8 Operation Panel Control Circuit Page Chapter 3 Disassembly and Assembly Page 3.1 Overview 3.1.1 Precautions for Disassembling the Printer 3.1.2 Tools WARNING 3-2 3.1.3 Service Check After Repair 3.1.4 Specifications for Screws 3-4 3.2 Printer Disassembly and Assembly Figure 3-1. Disassembly Flowchart The flowchart below show you the basic order for disassembly. Before disassembling any part of the printer, note the warnings in Section 3.1.1. START 3.2.1 HOUSING, UPPER Removal 3-6 3.2.2 Printer Mechanism Removal 3.2.3 C214 MAIN Board Removal 3.2.4 C214 PSB/PSE Board Removal 3.2.5 EP-ROM Replacement CHECK POINT 3.2.6 Printhead Removal 3.2.7 Ribbon Mask Removal 3.2.8 PAPER EXIT ASSY. Removal 3.2.9 Ribbon Mask Holder Removal 3.2.10 PW Detector (Top) Removal 3.2.11 MOTOR, CR Removal 3.2.12 Carriage Assy. Removal CHECK POINT Page 3.2.12.1 RATCHET, RD Removal 3.2.13 PAPER GUIDE Removal Page Chapter 3 Disassembly and Assembly Rev. A 3-21 3-22 3.2.14 Platen Removal 3.2.15 MOTOR, PF Removal Page 3.2.19 DETECTOR, PE, FRONT Removal 3.2.20 DETECTOR, PE, REAR Removal 3.2.21 LEVER, RELEASE Removal 3.2.22 Tractor ASSY. Removal Page Rev. A 4-1 4.1 Adjustment Overview Note*2) Note*1) 4.1.1 Required Adjustments 4.1.2 Required Adjustment Tools 4.2 Adjusting and Resetting the Printer Do not rotate the platen roller during this adjustment. 4.2.1 Platen Gap Adjustment Rev. A 4- 4.2.2 Factory Setting Page Rev. A 4- 4.2.3 Bi-d Adjustment Page Page 5.1 Overview 5- 5.2 Unit Level Troubleshooting Page Page Page Page Rev. A 5- Page View A R F R L 1-24 :Wire Number C :Common Terminal T:Thermistor Terminal Note*) Rev. A 5-11 5.3 Repairing the Power Supply Circuit Board Page Page 5.4 Repairing the Main Board Page Page 5.5 Repairing the Printer Mechanism Page Page 6.1 Preventive Maintenance Page Appendix A.1 Connector Summary A- Rev. A A- A- Page Page Page Page Page Page Page Page Page A-1 Page A.5 Dimension and Weight EPSON OVERSEAS MARKETING LOCATIONS As of September, 1996