The traditional use of organic colorants is to impart color to a substrate such as textiles, paper, plastics, and leather. However, in the last five years or so organic colorants have become increasingly important in the high­ technology (hi-tech) industries of electronics and particularly reprographics. In some of these reprographics applications the organic colorant is used in its traditional role of imparting color to a substrate, typically paper or plastic. Examples are dyes for ink-jet printing, thermally transferable dyes for thermal transfer printing, and dyes and pigments for colored toners in photocopiers and laser printers. In other applications it is a special effect of an organic colorant that is utilized, not its color. Examples are electrical effects, such as photoconduction and the electrostatic charging of toners, both of which are essential features for the operation of photocopiers and laser printers, and the selective absorption of infrared radiation, which is utilized in optical data storage. In electronic applications the organic colorant is often employed in a device. Typical examples include liquid crystal dyes, laser dyes, electro­ chromic dyes, dyes for solar cells, dyes for micro color filters, and dyes for nonlinear optical applications.

Inhalt

I. Historical Perspectives.- I. Historical Perspective.- II. Colorants for Electronics.- 1. Liquid Crystal Dyes.- 1.1. Introduction.- 1.2. Dye Types.- 1.3. Future Trends.- 1.4. Summary.- References.- 2. Micro Color Filters.- 2.1. Introduction.- 2.2. Flat Screen Televisions.- 2.3. Color Filter Preparation.- 2.3.1. Dyeing Method.- 2.3.2. Pigment Method.- 2.4. Spectral Characteristics.- 2.5. Summary.- References.- 3. Laser Dyes.- 3.1. Introduction.- 3.2. Basic Theory.- 3.3. Dye Types.- 3.4. Summary.- References.- 4. Colorants for Nonlinear Optics.- 4.1. Introduction.- 4.2. Nonlinear Optical Effects and Applications.- 4.3. Molecular Polarizability.- 4.4. Nonlinear Optical Molecules.- 4.5. Molecular Alignment.- 4.6. Summary.- References.- 5. Solar Cells.- 5.1. Introduction.- 5.2. Photosynthesis Mimics.- 5.3. Miscellaneous Colorants.- 5.4. Luminescent Solar Cells.- 5.5. Applications.- 5.6. Summary.- References.- 6. Electrochromic Dyes.- 6.1. Introduction.- 6.2. Electrochromic Displays.- 6.3. Electrochromic Printing.- 6.4. Summary.- References.- III. Colorants for Reprographics.- 7. Electrophotography.- 7.1. Introduction.- 7.2. Photocopying and Laser/Light Emitting Diode Printing Processes.- 7.2.1. Photocopying Process.- 7.2.2. Laser/Light Emitting Diode Printing Process.- 7.2.3. Color Copying Process.- 7.3. Key Chemical Components.- 7.4. Photoconductors.- 7.4.1. General Features.- 7.4.2. Inorganic Photoconductors.- 7.4.3. Organic Photoconductors.- 7.4.4. Photoconductive Mechanism.- 7.5. Toners.- 7.5.1. General Features.- 7.5.2. Charge Control Agents.- 7.5.2.1. Negative Charge Control Agents.- 7.5.2.2. Positive Charge Control Agents.- 7.5.2.3. Noncolored Charge Control Agents.- 7.5.2.4. Polymeric Charge Control Agents.- 7.5.2.5. Mode of Action.- 7.5.3. Colored Toners.- 7.6. Photoactive Pigment Electrophoresis.- 7.6.1. Basic Process.- 7.6.2. Full Color Process.- 7.6.3. Problems of Photoactive Pigment Electrophoresis.- 7.6.4. Correlation with Organic Photoconductors.- 7.7. Special Effects.- 7.7.1. Nonphotocopiable Documents.- 7.7.2. Photomicrolithography.- 7.7.3. Prepress Proofing.- 7.7.4. Transfer Printing Toners.- 7.8. Summary.- References.- 8. Thermography.- 8.1. Introduction.- 8.2. Direct Thermal Printing.- 8.3. Pressure-Sensitive Printing.- 8.4. Mead Photocapsule (CYCOLOR) Process.- 8.5. Thermal Wax Transfer.- 8.5.1. Color Sheet.- 8.5.2. Receiver Sheet.- 8.5.3. Patent Activity.- 8.5.4. Electrothermal Printing.- 8.5.5. Laser Transfer.- 8.6. Dye Diffusion Thermal Transfer.- 8.6.1. Electronic Photography.- 8.6.2. History and Development.- 8.6.3. Dye Diffusion Thermal Transfer Process.- 8.6.4. Dyesheet.- 8.6.5. Dye Diffusion Thermal Transfer Dyes.- 8.6.5.1. Yellow Dyes.- 8.6.5.2. Magenta Dyes.- 8.6.5.3. Cyan Dyes.- 8.6.6. Receiver Sheet.- 8.7. Summary.- References.- 9. Ink-Jet Printing.- 9.1. Introduction.- 9.2. History and Development.- 9.3. Technology.- 9.3.1. Continuous Ink-Jet.- 9.3.2. Drop-on-Demand Ink-Jet.- 9.4. Ink-Jet Inks.- 9.4.1. General Features.- 9.4.2. Aqueous Inks.- 9.4.3. Solvent Inks.- 9.4.4. Hot-Melt Inks.- 9.4.5. Ink-Paper Interactions.- 9.5. Ink-Jet Colorants.- 9.5.1. Properties Required.- 9.5.1.1. Color.- 9.5.1.2. Color Strength.- 9.5.1.3. Solubility.- 9.5.1.4. Insolubles.- 9.5.1.5. Electrolytes/Metals.- 9.5.1.6. Fastness Properties.- a. Light Fastness.- b. Water Fastness.- c. Smear Fastness.- 9.5.1.7. Shade.- 9.5.1.8. Toxicology.- 9.5.1.9. Thermal Stability.- 9.5.2. Dye Types.- 9.5.3. Black Dyes.- 9.5.3.1. Water Soluble.- 9.5.3.2. Solvent/Resin Soluble.- 9.5.4. Yellow Dyes.- 9.5.4.1. Water Soluble.- 9.5.4.2. Solvent/Resin Soluble.- 9.5.5. Magenta Dyes.- 9.5.5.1. Water Soluble.- 9.5.5.2. Solvent/Resin Soluble.- 9.5.6. Cyan Dyes.- 9.5.6.1. Water Soluble.- 9.5.6.2. Solvent/Resin Soluble.- 9.6. Applications of Ink-Jet Printing.- 9.7. Summary.- References.- 10. Electrography, Ionography, and Magnetography.- 10.1. Introduction.- 10.2. Electrography.- 10.3. Ionography.- 10.4. Magnetography.- 10.5. Summary.- References.- IV. Future Perspectives.- 11. Infrared Absorbers.- 11.1. Introduction.- 11.2. Effects of Infrared Absorbers.- 11.3. Classification of Infrared Absorbers.- 11.3.1. Nitroso.- 11.3.2. Cyanines.- 11.3.3. Nigrosines.- 11.3.4. Triphenylmethanes.- 11.3.5. Imminium and Diimminium.- 11.3.6. Squariliums and Croconiums.- 11.3.7. Nickel Dithiolenes and Related Compounds.- 11.3.8. Quinones.- 11.3.8.1. Simple Naphthoquinones.- 11.3.8.2. Extended Quinones.- 11.3.8.3. CI Disperse Blue 60 Analogues.- 11.3.8.4. Benzoquinones.- 11.3.9. Phthalocyanines.- 11.3.9.1. Polymorphic Pigments.- 11.3.9.2. Metallation.- 11.3.9.3. Donor Substitutents.- 11.3.9.4. Extended Conjugation.- 11.3.10. Azo.- 11.3.11. Indoanilines.- 11.3.12. Donor-Acceptor Molecules.- 11.3.13. Other Classes.- 11.4. Applications of Infrared Absorbers.- 11.4.1. Heat-Ray Blocking.- 11.4.2. Energy Conversion.- 11.4.2.1. Thermal Imaging.- 11.4.2.2. Flash Fusion of Toners.- 11.4.2.3. Solar Heating.- 11.4.3. Optical Effects (Utilizing Laser Radiation).- 11.4.3.1. Organic Photoconductors.- 11.4.3.2. Optical Data Storage.- 11.4.3.3. Automatic Identification.- 11.4.4. Optical Effects (Utilizing Electromagnetic Radiation).- 11.5. Colorless Infrared Absorbers.- 11.6. Summary.- References.- 12. Toxicology.- 12.1. Introduction.- 12.2. Hazards of Colorants.- 12.3. Regulations and Registration.- 12.4. Structure-Carcinogenicity Guidelines for Organic Colorants and Related Intermediates.- 12.4.1. Effect of Physical Properties on Carcinogenicity.- 12.4.2. Classes of Carcinogens by Chemical Structure.- 12.4.2.1. Carcinogens from Nitrogen Electrophiles.- a. Aromatic Nitro and Amino Compounds.- b. Nitrosamines.- c. Hydrazines and Hydroxylamines.- d. Azo Dyes.- e. Anthraquinone Dyes.- f. Cationic Dyes.- 12.4.2.2. Carcinogens from Carbon Electrophiles.- a. Direct Acting Alkylating Agents.- b. Polycyclic Aromatic Hydrocarbons.- c. Michael Acceptors.- 12.4.3. Metals.- 12.4.4. Carcinogenic Impurities.- 12.5. Risk Assessment.- 12.6. Summary.- References.- 13. Future Trends.- 13.1. Introduction.- 13.2. Colorants for Electronics.- 13.3. Colorants for Reprographics.- 13.3.1. The Paperless Office.- 13.3.2. Competing Technologies.- 13.3.3. General Predictions.- 13.3.4. Specific Predictions.- 13.3.4.1. Electrophotography.- 13.3.4.2. Thermal.- 13.3.4.3. Ink-Jet.- 13.3.4.4. Other Technologies.- 13.4. Toxicology.- 13.5. Summary.- Reference.