Chemistry and Technology of Printing and Imaging Systems

239 Pages·1996·8.536 MB·English

by  P. Gregory (auth.), P. Gregory (eds.)

Chemistry and Technology of
Printing and Imaging Systems
Chemistry and Technology
of
Printing and Imaging Systems
Edited by
P. GREGORY
Zeneca Specialties
Manchester
SPRINGER-SCIENCE+BUSINESS MEDIA, B.V.
First edition 1996
© 1996 Springer Science+Business Media Dordrecht
OriginalIy published by Chapman & HalI in 1996
Softcover reprint ofthe hardcover lst edition 1996
Typeset in 10/12pt Times by Cambrian Typesetters, Frim1ey, Surrey
ISBN 978-94-010-4265-9 ISBN 978-94-011-0601-6 (eBook)
DOI 10.1007/978-94-011-0601-6
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A cata10gue record for this book is available from the British Library
Library of Congress Catalog Card Number: 95-76794
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Preface
Printing and imaging has a major impact on everyone. From the obvious
examples of newspapers, magazines and comics through to photographs,
currency and credit cards, and even the less obvious example of compact
discs, everyone is familiar with the end products of printing and imaging.
Until recently, the major printing and imaging technologies have been
impact printing and silver halide photography. Important impact printing
technologies are offset lithography, gravure, flexography and screen
printing. All these technologies, including silver halide photography, are
mature and have changed little over the past few decades. In contrast, the
phenomenal growth of silicon chip technology over the past 15 years or so
has spawned a new era of printing and imaging systems, the so-called non
impact (or electronic) printers.
Not all the non-impact printing technologies are of equal commercial
importance. Some, like diazotype and conventional photolithography, are
mature and are declining in importance. Other technologies, though
relatively new, have not achieved notable commercial success. Electro
graphy and magnetography fall into this category. The remaining tech
nologies such as optical data storage (the technology used in compact
discs), thermography (the technology used in electronic photography), ink
jet printing and electrophotography are the non-impact printing tech
nologies that are both modern and which have achieved remarkable
commercial success, especially ink-jet printing and electrophotography.
Indeed, electrophotography, the technology which embraces photocopiers
and laser printers, together with the more recent ink-jet printers, are now
the standard office printers, having displaced the once dominant impact
printers such as typewriters, daisywheel and dot-matrix. This revolution
has seen printing move from the workshop and darkroom into the office
and home.
The advances in non-impact printing technologies are now beginning to
be incorporated into some of the mature technologies to improve their
performance. Examples include the use of photoconductor technology
used in electrophotography, and laser imaging used in optical data storage,
to produce lithographic plates, both technologies having advantages over
the established photolithography. Indeed, as time progresses there will be
more of this interaction of modern technologies with mature technologies.
Because of the rapid changes in the printing and imaging technologies
over the last decade, the time is ripe for a book. I am honoured to have
VI PREFACE
been asked to edit such a book and wish to thank all the contributors for
their excellent contributions.
Finally I would like to thank my wife, Vera, and two sons, Andrew and
Michael, for their perseverance and patience during this project, and Dr
Alan Calder, General Manager of Zeneca Specialties, for use of the library
and secretarial facilities, especially Amanda Collier for typing several
chapters.
Peter Gregory
Contributors
P. Bergthaller Agfa Gevaert AG, Postfach 10 01 60, D5 1301 Lever
kusen, Germany
R. Bradbury Zeneca Specialties, PO Box 42, Hexagon House, Blackley,
Manchester M9 8ZS, UK
R.S. Gairns Zeneca Specialties, PO Box 42, Hexagon House, Blackley,
Manchester M9 8ZS, UK
P. Gregory Zeneca Specialties, PO Box 42, Hexagon House, Blackley,
Manchester M9 8ZS, UK
P.A. Hunt ICI Imagedata, Brantham, Manningtree, Essex COl1
INL, UK
T .S. Jewitt Department of Communication Media, Manchester
Metropolitan University, Cavendish Street, Manchester
M15 3BR, UK
R. W. Kenyon Zeneca Specialties, PO Box 42, Hexagon House, Blackley,
Manchester M9 8ZS, UK
Contents
1 Setting the scene 1
P. GREGORY
1.1 From maturity to mayhem 1
1.2 The ubiquitous silicon chip 1
1.3 The environment 2
1.4 Themes and focii 3
References 3
2 Traditional impact printing 4
T.S. JEWITT
2.1 Introduction 4
2.2 A brief history of printing 4
2.3 Printing technologies 7
2.3.1 Relief printing 7
2.3.2 Letterpress 7
2.3.3 Flexography 9
2.3.4 Intaglio printing 11
2.3.5 Planographic printing 13
2.4 The offset printing press 16
2.4.1 Image quality 16
2.4.2 The image on the plate 16
2.4.3 The offset blanket 17
2.4.4 Fount solution 17
2.5 Lithographic inks 18
2.5.1 Cold-set web-offset inks 18
2.5.2 Heat-set web-offset inks 19
2.5.3 Sheet-fed lithographic inks 19
2.6 The printing industry 21
2.7 Applications of the printing processes 22
2.7.1 Letterpress 22
2.7.2 Flexography 22
2.7.3 Gravure 22
2.7.4 Screen printing 23
2.7.5 Lithography 24
2.7.6 Web offset 24
2.8 Commercial aspects of the British printing industry 25
2.9 Electronic imaging 26
2.9.1 Scanning 27
2.9.2 Output 28
2.9.3 Proofing 28
2.9.4 Digital platemaking 29
2.9.5 Digital printing 31
2.10 Printing and the environment 33
References and further reading 34
X CONTENTS
3 Silver halide photography 35
P. BERGTHALLER
3.1 History and evolution of photographic imaging systems 35
3.1.1 Photography in black-and-white 35
3.1.2 Concepts of photography in colour: the steps of the
pioneers 36
3.1.3 Silver halide photography today: the market 36
3.2 The physical basis of silver halide photography 37
3.2.1 A brief look at the elementary processes
in the silver halide crystal 37
3.2.2 The photographic emulsion 38
3.2.3 Photographic development 38
3.2.4 Detail rendition 39
3.2.5 Development and colour: subtractive colour photography vs.
additive colour photography 39
3.3 Photographic materials 41
3.3.1 Film 41
3.3.2 Printing media 44
3.4 The chemical constituents of photographic media 53
3.4.1 Emulsion ingredients and additives 53
3.4.2 Developers and processing chemistry 53
3.4.3 Colour couplers and special-purpose couplers 55
3.4.4 The chemistry of the silver-dye-bleach process 63
3.4.5 The chemistry of dye diffusion systems 64
3.5 Photographic quality 66
3.6 Future of photographic media 68
3.6.1 Frontiers of the technically feasible 69
3.6.2 Remote sensing and recording 69
3.6.3 Digital storage of photographic images: a powerful tool
for information management and archiving 70
3.6.4 The merging of technologies: hybrid media and
digital imaging 70
3.6.5 The merging of uses (communication and entertainment) 72
3.6.6 Ecological challenges of photographic processing 73
3.6.7 The advanced photo system 74
References 74
4 Electrophotography 76
R.S. GAIRNS
4.1 Introduction 76
4.2 The technology ofxerography 76
4.2.1 Charging 77
4.2.2 Exposure 79
4.2.3 Image enhancement 80
4.2.4 Development 83
4.2.5 Fixing and cleaning 85
4.3 Consumables 86
4.3.1 Photoconductors 86
4.3.2 Charge-generation materials (CGMs) 89
4.3.3 Charge-transport materials (CTMs) 93
4.3.4 Developer 97
4.4 Advantages of electrophotography 103
4.5 Limitations of electrophotography 104
4.6 Competition 104
CONTENTS xi
4.7 Synergy 105
4.7.1 Photoactive pigment electrophoresis (PA PE) 105
4.7.2 Electrography and ionography 106
4.7.3 Lithography 106
4.7.4 TonerJet 108
4.8 Uses of electrophotography 108
4.9 Toxicology and the environment 109
4.10 Future 110
References 110
5 Inkjet printing 113
R.W. KENYON
5.1 Introduction 113
5.2 Ink jet technology 114
5.2.1 Continuous ink jet 114
5.2.2 Drop-on-demand ink jet 115
5.3 Ink jet inks 119
5.3.1 General features 119
5.3.2 Aqueous inks 119
5.3.3 Solvent inks 120
5.3.4 Hot-melt inks 121
5.4 Ink jet colorants 121
5.4.1 Black dyes (first generation) 121
5.4.2 Colour dyes (first generation) 123
5.5 Second-generation colorants 126
5.6 Phase-change colorants 129
5.7 Colorants for industrial ink jet printers 130
5.8 Ink jet ink/colorant research 130
5.9 Advantages/limitations of ink jet 131
5.10 Uses of ink jet printers 132
5.10.1 Office segment 132
5.10.2 Industrial segment 133
5.10.3 Colour filters for LCDs (Liquid crystal displays) 134
5.10.4 Ink jet printing oftextiles 134
5.11 Toxicology and the environment 136
5.12 Futureofinkjet 137
References 138
6 Thermal printing 139
R. BRADBURY
6.1 Introduction 139
6.2 Direct thermal printing 140
6.2.1 Colour formers 142
6.2.2 Developers 144
6.2.3 Sensitisers 145
6.2.4 Multicolour thermal paper 147
6.2.5 Direct thermal markets 149
6.3 Mead Cycolor process 149
6.3.1 Photoinitiators 150
6.4 Dye-diffusion thermal transfer (D2T2) 151
6.4.1 Dye sheet ( dye donor sheet) 152
6.4.2 Receiver sheet 154
6.4.3 Dye-diffusion thermal-transfer dyes 155
6.4.4 D2T2market 162
XII CONTENTS
6.5 Thermal-melt transfer 163
6.5.1 Dyesheet 163
6.5.2 Melt-transfer colorants 164
6.5.3 Receiver sheets 166
6.5.4 Printing 166
6.5.5 Thermal melt-transfer market 166
References 167
7 Optical data-storage systems 168
P.A. HUNT
7.1 Introduction 168
7.2 Principles of operational functionality 169
7.2.1 Read-only memory (ROM) 169
7.2.2 Erasable versus write-once 170
7.2.3 Physical and chemical requirements 170
7.3 System options 170
7.3.1 Metallic ablative (WORM) 171
7.3.2 Metallic phase-change (WO RM and erasable) 172
7.3.3 Dye-polymer ablative (WORM) 173
7.3.4 Photochromic dye (erasable) 178
7.3.5 Liquid crystals (WORM and erasable) 179
7.3.6 Metallic interference (WORM) 181
7.4 Technical performance features of ODS systems 181
7.4.1 Performance advantages of ODS systems 181
7.4.2 Performance limitations in ODS systems 183
7.5 Commercial performance features 183
7.6 Comparison with alternative technologies 183
7.6.1 Magnetic media 185
7.6.2 Magneto-optical (MO) media 186
7.7 Related technologies 188
7.8 Applications of ODS 189
7.9 Toxicology and environmental considerations 190
7.10 The future 191
References 193
8 Electrostatic, ionographic, magnetographic and embryonic
printing technologies 195
P. GREGORY
8.1 Introduction 195
8.2 Electrographic printing 195
8.3 Ionographicprinting 197
8.4 Magnetographic printing 199
8.5 Embryonic printing technologies 200
8.5.1 High-resolution dry-processing film (VerdeFilm) 200
8.5.2 Toner fusion xeroprinting 204
8.5.3 TonerJet 205
8.6 Future prospects 206
References 206