Troubleshooting and Repairing Computer Printers Other Books by Stephen J. Bigelow Troubleshooting, Maintaining, & Repairing Personal Computers Troubleshooting and Repairing Computer Monitors Troubleshooting and Repairing Notebook, Palmtop, and Pen Computers Maintain and Repair Your Computer Printer and Save a Bundle Troubleshooting and Repairing Computer Printers 2nd edition Stephen J. Bigelow TAB Books Imprint of McGraw-Hill New York San Francisco Washington, D.C. Auckland Bogota caracas Usbon london Madrid Mexico City Milan Montreal New Delhi San Juan Singapore Sydney Tokyo Toronto McGraw-Hill gz A Division ofTheMcGraw·HiUCompanies ©1996 by The McGraw-Hill Companies, Inc. Printed in the United States of America. All rights reserved. The publisher takes no responsibility for the use of any materials or methods described in this book, nor for the products thereof. pbk 7 8 9 DOC/DOC 9 0 0 9 8 he 2 3 4 5 6 7 8 9 DOC/DOC 9 0 0 9 8 Product or brand names used in this book may be trade names or trademarks. Where we believe that there may be proprietary claims to such trade names or trademarks, the name has been used with an initial capital or it has been capitalized in the style used by the name claimant. Regardless of the capitalization used, all such names have been used in an editorial manner without any intent to convey endorsement of or other affiliation with the name claimant. Neither the author nor the publisher intends to express any judgment as to the validity or legal status of any such proprietary claims. Library of Congress Cataloging-in-Publication Data Bigelow, Stephen J. Troubleshooting and repairing computer printers I by Stephen J. Bigelow.-2nd ed. p. em. Includes bibliographical references and index. ISBN 0-07-005731-1. ISBN 0-07-005732-X (pbk.) 1. Printers (Data processing systems)-Maintenance and repair. I. Title TK7887.7.B55 1996 681 '.62-dc20 96-16467 CIP McGraw-Hill books are available at special quantity discounts to use as premiums and sales promotions, or for use in corporate training programs. For more information, please write to the Director of Special Sales, McGraw-Hill, 11 West 19th Street, New York, NY 10011. Or contact your local bookstore. Acquisitions editor: Roland S. Phelps Editorial team: Melanie Brewer, Book Editor Andrew Yoder, Managing Editor Lori Flaherty, Executive Editor Joann Woy, Indexer Production team: Katherine G. Brown, Director Ollie Harmon, Coding Wanda S. Ditch, Desktop Operator Lorie L. White, Proofreading Jeffrey Miles Hall, Computer Artist Design team: Jaclyn J. Boone, Designer Katherine Lukaszewicz, Associate Designer EL3 005732X This book is dedicated to my wonderful wife, Kathleen. Without her loving encouragement and support, this book would still have been possible, but not nearly worth the trouble. Contents Acknowledgments xvii Preface xix Introduction xxi 1 A modern printer 1 Features & specifications 2 Power requirements 3 Interface compatibility 3 Print capacity 4 Paper handling 7 Print characteristics 8 Reliability/life information 11 Environmental information 11 Physical information 12 Understanding the typical assemblies 12 Paper transport assembly 12 Print head assembly 16 Print head transport (carriage) 22 Power supply 23 Electronic control unit 24 2 Typical components 27 Mechanical components 27 ~ Gears 27 Pulleys 30 ~ 31 ~Rollers -Reducing friction 32 - Electromechanical components 33 Electromagnetism 33 ~ Relays 35 Solenoids 36 - Motors 37 Electronic components 39 Resistors 39 Capacitors 41 Inductors 43 Diodes 45 Transistors 47 Optoisolators 50 Integrated circuits 51 3 Conventional printing technologies 53 Impact printing 54 The dot mechanics 54 Driving the dot 55 Dot specifications 57 Advantages & disadvantages of DMI printing 60 Thermal printing 61 Thermal head fabrication 61 Serial head operation 64 Line head operation 66 Thermal printing media 68 Advantages & disadvantages of TOM printing 69 Ink jet printing 70 Inside the ink jet print head 70 Piezoelectric pumps 71 Bubble pumps 72 Monochrome vs. color 74 Ink considerations 74 Recycling considerations 75 Paper considerations 75 Advantages & disadvantages of ink jet printing 76 4 Electrophotographic printing technology 77 The classical electrophotographic approach 77 Cleaning 78 Charging 80 Writing 81 Developing 82 Transfer & discharge 83 Fusing 84 Writing mechanisms 85 Lasers 86 LEOs 88 The electrophotographic cartridge 90 Protecting an EP cartridge 92 Refinements to the EP process 93 Charge rollers 93 Erase lamps 94 Doctor blade 94 New EP coatings 95 Toner paddle 95 Newtoner 95 5 Using test equipment 97 Small tools & materials 97 Hand tools 97 Materials 99 Soldering 100 Soldering background 100 Irons &t ips 101 Soldering technique 104 Surface mount soldering 105 Desoldering 107 Test equipment 107 Multimeters 108 Measuring voltage 110 Measuring current 111 Measuring resistance 111 Checking a capacitor 113 Semiconductor checks 115 Logic probes 117 Oscilloscopes 118 Controls 119 Oscilloscope specifications 120 Oscilloscope start-up procedures 121 Voltage measurements 123 Time & frequency measurements 124 6 Troubleshooting guidelines 127 The troubleshooting cycle 127 Define your symptoms 128 Identify & isolate 129 Repair or replace 130 Retest 131 Gathering technical data 131 The user's manual 132 Fax back information 132 On-line resources 132 Technical data & schematics 134 Electricity hazards 135 Understanding power supply dangers 135 The dangers of ozone 136 Steps for protection 136 Static electricity 137 Static formation 137 Device damage 138 Controlling static electricity 139 Other EP printer hazards 140 Scanning laser 140 Fusing assembly 141 Ozone hazards 141 Disassembly hints 141 Housing disassembly 141 Electromechanical disassembly 143 Reassembly hints 143