EP0599369A1 - Wärmeempfindliches Aufzeichnungsmaterial - Google Patents

Wärmeempfindliches Aufzeichnungsmaterial Download PDF

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Publication number
EP0599369A1
EP0599369A1 EP93203120A EP93203120A EP0599369A1 EP 0599369 A1 EP0599369 A1 EP 0599369A1 EP 93203120 A EP93203120 A EP 93203120A EP 93203120 A EP93203120 A EP 93203120A EP 0599369 A1 EP0599369 A1 EP 0599369A1
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EP
European Patent Office
Prior art keywords
recording material
indane
bis
material according
recording
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Granted
Application number
EP93203120A
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English (en)
French (fr)
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EP0599369B1 (de
Inventor
Carlo C/O Agfa-Gevaert N.V. Uyttendaele
Jean-Marie C/O Agfa-Gevaert N.V. Dewanckele
Roland C/O Agfa-Gevaert N.V. Beels
Luc C/O Agfa-Gevaert N.V. Leenders
Robert C/O Agfa-Gevaert N.V. Van Haute
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Agfa Gevaert NV
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Agfa Gevaert NV
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Priority to EP19930203120 priority Critical patent/EP0599369B1/de
Publication of EP0599369A1 publication Critical patent/EP0599369A1/de
Application granted granted Critical
Publication of EP0599369B1 publication Critical patent/EP0599369B1/de
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Expired - Lifetime legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
    • G03C1/00—Photosensitive materials
    • G03C1/494—Silver salt compositions other than silver halide emulsions; Photothermographic systems ; Thermographic systems using noble metal compounds
    • G03C1/498—Photothermographic systems, e.g. dry silver
    • G03C1/4989—Photothermographic systems, e.g. dry silver characterised by a thermal imaging step, with or without exposure to light, e.g. with a thermal head, using a laser

Definitions

  • the present invention relates to a recording material suited for use in direct thermal imaging.
  • Thermal imaging or thermography is a recording process wherein images are generated by the use of imagewise modulated thermal energy.
  • thermography two approaches are known :
  • Thermal dye transfer printing is a recording method wherein a dye-donor element is used that is provided with a dye layer wherefrom dyed portions or incorporated dye is transferred onto a contacting receiver element by the application of heat in a pattern normally controlled by electronic information signals.
  • the optical density of transparencies produced by the thermal transfer procedure is rather low and in most of the commercial systems - in spite of the use of donor elements specially designed for printing transparencies - only reaches 1 to 1.2 (as measured by a Macbeth Quantalog Densitometer Type TD 102).
  • a considerably higher transmission density is asked for. For instance in the medical diagnostical field a maximal transmission density of at least 2.5 is desired.
  • Thermography is concerned with materials which are not photosensitive, but are sensitive to heat or thermosensitive. Imagewise applied heat is sufficient to bring about a visible change in a thermosensitive imaging material.
  • thermographic recording materials are of the chemical type. On heating to a certain conversion temperature, an irreversible chemical reaction takes place and a coloured image is produced.
  • a typical heat-sensitive copy paper includes in the heat-sensitive layer a water-insoluble silver salt, e.g. silver stearate and an appropriate organic reducing agent, of which 4-methoxy-1-hydroxydihydronaphthalene is a representative.
  • a water-insoluble silver salt e.g. silver stearate
  • an appropriate organic reducing agent of which 4-methoxy-1-hydroxydihydronaphthalene is a representative.
  • a heterocyclic organic toning agent such as phthalazinone is added to the composition of the heat-sensitive layer.
  • the heat-sensitive copying paper is used in "front-printing” or “back-printing” as illustrated in Figures 1 and 2 of US-P 3,074,809.
  • thermal printing signals are converted to electric pulses and then through a driver circuit selectively transferred to a thermal printhead.
  • the thermal printhead consists of microscopic heat resistor elements, which convert the electrical energy into heat via the Joule effect.
  • the electric pulses thus converted into thermal signals manifest themselves as heat transferred to the surface of the thermal paper wherein the chemical reaction resulting in colour development takes place.
  • Heat-sensitive copying materials including a redox-system of light-insensitive organic silver salt and organic reducing agent in the presence of a toning agent may well provide relatively high maximal optical densities but suffer normally from a too high minimal optical density and rather poor stability under conditions of moderate heating (about 50 °C) and relative humidity in the range of 30 to 70 %.
  • the organic reductor should not react prematurely with the organic silver salt under moderate heating conditions but on the other hand it should be an effective reductor at temperatures provided in direct thermal imaging e.g. by thermal printheads.
  • temperatures provided in direct thermal imaging e.g. by thermal printheads.
  • the surface temperature may reach 300-400 °C while the copying paper contacts the printheads at pressures of 200-500 g/cm2 to ensure sufficient heat transfer.
  • a recording material suited for use in direct thermal imaging comprises : (i) a support and (ii) at least one imaging layer containing uniformly distributed in a polymeric binder (1) a substantially light-insensitive organic silver salt in thermal working relationship with (2) at least one organic reducing agent, characterized in that said organic reducing agent is a polyhydroxy spiro-bis-indane.
  • thermo working relationship means here that said substantially light-insensitive organic silver salt and said reducing agent by means of heat can react to form metallic silver.
  • said ingredients (1) and (2) may be present in a same layer or different layers wherefrom by heat they can come into reactive contact with each other, e.g. by diffusion or mixing in the melt.
  • a heat-sensitive recording material containing silver behenate and 4-methoxy-1-naphthol as reducing agent in adjacent binder layers is described in Example 1 of US-P 3,094,417.
  • the present invention includes likewise the use of said recording material in direct thermal imaging.
  • thermographic process the application of the heat pattern proceeds in direct thermal imaging mode, whereby is meant that during the application of said heat pattern a visible image is formed in said recording material without the aid of substances that are thermally pattern-wise transferred thereon and/or therein.
  • R represents hydrogen or alkyl, e.g. methyl or ethyl
  • each of R1 and R2 (same or different) represents H, an alkyl group, e.g. methyl, ethyl or propyl, an alkenyl group or a cycloalkyl group, e.g. cyclohexyl group, or R1 and R2 together represent the atoms necessary to close a homocyclic non-aromatic ring, e.g.
  • each of R3 and R4 represents H, an alkyl group, e.g. methyl, ethyl or propyl, an alkenyl group or a cycloalkyl group, e.g. cyclohexyl group, or R3 and R4 together represent the atoms necessary to close a homocyclic non-aromatic ring, e.g. cyclohexyl, each of Z1 and Z2 (same or different) represents the atoms necessary to close an aromatic ring or ring system, e.g. benzene ring, substituted with at least two hydroxyl groups in ortho- or para-position and optionally further substituted with at least one hydrocarbon group, e.g an alkyl or aryl group.
  • R3 and R4 represents H, an alkyl group, e.g. methyl, ethyl or propyl, an alkenyl group or a cycloalkyl group, e.g. cyclohe
  • a preferred recording material according to the present invention contains a polyhydroxy spiro-bis-indane that is di-alkyl substituted in both of its indane rings, more particularly in the 3-and 3'-position of the spiro-bis-indane.
  • a particularly preferred recording material according to the present invention contains a polyhydroxy spiro-bis-indane compound corresponding to the following general formula (II) : wherein : R represents hydrogen or alkyl, e.g. methyl or ethyl, each of R1 and R2 (same or different) represents, an alkyl group, preferably methyl group or a cycloalkyl group, e.g. cyclohexyl group, each of R3 and R4 (same or different) represents, an alkyl group, preferably methyl group or a cycloalkyl group, e.g. cyclohexyl group, and n is a positive integer 2 or 3, m represents zero or is a positive integer 1, 2 or 3, and at least two of the hydroxyl groups of said formula are in ortho- or para-position.
  • R represents hydrogen or alkyl, e.g. methyl or ethyl
  • each of R1 and R2 represents, an alkyl
  • polyhydroxy-spiro-bis-indane compounds described in US-P 3,440,049 as photographic tanning agent more especially 3,3,3',3'-tetramethyl-5,6,5',6'-tetrahydroxy-1,1'-spiro-bis-indane (called indane I) and 3,3,3',3'-tetramethyl-4,6,7,4',6',7-hexahydroxy-1,1'-spiro-bis-indane (called indane II).
  • Indane is also known under the name hydrindene.
  • indane (I) can proceed by condensation of catechol with acetone such as disclosed by Baker, J. Chem. Soc., 1943, pp. 1678-81.
  • indane (II) can proceed by the condensation of polyhydric phenols with acetone as disclosed by Fischer, Furling and Grant, J. Am. Chem. Soc., 58 , pp. 820-22 (1936).
  • Alkyl and hydroxy substituted spiro-bis-indanes where the hydroxyls are in ortho- or para-position of the aromatic rings can also be prepared as described in German patent 1,092,648.
  • polyhydroxy spiro-bis-indane reducing agents may be used in a thermographic recording material according to the present invention in combination with other reducing agents, e.g. sterically hindered phenols operating as auxiliary reducing agents that on heating become reactive partners in the reduction of a non-light-sensitive silver salt such as silver behenate, or are used in combination with bisphenols as described in US-P 3,547,648.
  • reducing agents e.g. sterically hindered phenols operating as auxiliary reducing agents that on heating become reactive partners in the reduction of a non-light-sensitive silver salt such as silver behenate, or are used in combination with bisphenols as described in US-P 3,547,648.
  • Other optionally used reducing agents in conjunction with said polyhydroxy spiro-bis-indanes to give increased image density are the metal ion image amplifier materials such as stannous stearate described in US-P 3,460,946 and 3,547,648.
  • the pattern-wise or image-wise heating of the recording material proceeds by Joule effect heating in that selectively energized electrical resistors of a thermal head array are used in contact or close proximity with said recording layer.
  • an electrically resistive ribbon consisting e.g. of a multilayered structure of a carbon-loaded polycarbonate coated with a thin aluminium film (ref. Progress in Basic Principles of Imaging Systems - Proceedings of the International Congress of Photographic Science GmbH (Cologne), 1986 ed. by Friedrich Granzer and Erik Moisar - Friedr. Vieweg & Sohn - Braunschweig/Wiesbaden, Figure 6. p. 622).
  • Current is injected into the resistive ribbon by electrically addressing a print head electrode contacting the carbon-loaded substrate, thus resulting in highly localized heating of the ribbon beneath the energized electrode.
  • the aluminium film makes direct contact with the heat-sensitive recording layer or its protective outermost layer.
  • the recording layer of said recording material is heated image-wise or pattern-wise by means of a modulated laser beam.
  • image-wise modulated laser light is used to heat the recording layer image-wise by means of substances converting absorbed laser light, e.g. infrared radiation into heat.
  • the recording layer or a layer in intimate thermo-conductive contact therewith contains light-into-heat converting substances, e.g. infrared radiation absorbing substances.
  • the imagewise applied laser light has not necessarily to be infrared light since the power of a laser in the visible light range and even in the ultraviolet region can be thus high that sufficient heat is generated on absorption of the laser light in the recording material.
  • laser which may be a gas laser, gas ion laser, e.g. argon ion laser, solid state laser, e.g. Nd:YAG laser, dye laser or semi-conductor laser.
  • the image- or pattern-wise wise heating of the recording material proceeds by means of pixelwise modulated ultra-sound, using e.g. an ultrasonic pixel printer as described e.g. in US-P 4,908,631.
  • the image signals for modulating the ultrasonic pixel printer, laser beam or electrode current are obtained directly e.g. from opto-electronic scanning devices or from an intermediary storage means, e.g. magnetic disc or tape or optical disc storage medium, optionally linked to a digital image work station wherein the image information can be processed to satisfy particular needs.
  • an intermediary storage means e.g. magnetic disc or tape or optical disc storage medium
  • Direct thermal imaging can be used for both the production of transparencies and reflection type prints.
  • the support will be transparent or opaque, e.g. having a white light reflecting aspect.
  • a paper base is present which may contain white light reflecting pigments, optionally also applied in an interlayer between the recording layer and said base.
  • said base may be colourless or coloured, e.g. has a blue colour.
  • Substantially light-insensitive organic silver salts particularly suited for use according to the present invention in the heat-sensitive recording layer in admixture with the above defined polyhyroxy spiro-bis-indanes are silver salts of aliphatic carboxylic acids known as fatty acids, wherein the aliphatic carbon chain has preferably at least 12 C-atoms, e.g. silver laurate, silver palmitate, silver stearate, silver hydroxystearate, silver oleate and silver behenate.
  • Modified aliphatic carboxylic acids with thioether group as described e.g. in GB-P 1,111,492 and other organic silver salts as described in GB-P 1,439,478, e.g.
  • silver benzoate and silver phthalazinone may be used likewise to produce a thermally developable silver image.
  • the silver image density depends on the coverage of the above defined polyhydroxy spiro-bis-indane reducing agent and organic silver salt(s) and has to be preferably such that on heating above 100 °C an optical density of at least 3 can be obtained.
  • the recording layer contains in admixture with said organic silver salt and reducing agents a so-called toning agent known from thermography or photo-thermography.
  • Suitable toning agents are the phthalimides and phthalazinones within the scope of the general formulae described in the already mentioned Re. 30,107. Further reference is made to the toning agents described in US-P 3,074,809, 3,446,648 and 3,844,797.
  • Other particularly useful toning agents are the heterocyclic toner compounds of the benzoxazine dione or naphthoxazine dione type within the scope of following general formula : in which : X represents O or NR5; each of R1, R2, R3 and R4 (same or different) represents hydrogen, alkyl, e.g. C1-C20 alkyl, preferably C1-C4 alkyl, cycloalkyl, e.g.
  • cyclopentyl or cyclohexyl alkoxy, preferably methoxy or ethoxy, alkylthio with preferably up to 2 carbon atoms, hydroxy, dialkylamino of which the alkyl groups have preferably up to 2 carbon atoms or halogen, preferably chlorine or bromine; or R1 and R2 or R2 and R3 represent the ring members required to complete a fused aromatic ring, preferably a benzene ring, or R3 and R4 represent the ring members required to complete a fused aromatic aromatic or cyclohexane ring. Toners within the scope of said general formula are described in GB-P 1,439,478 and US-P 3,951,660.
  • a toner compound particularly suited for use in combination with said polyhydroxy spiro-bis-indane reducing agents is 3,4-dihydro-2,4-dioxo-1,3,2H-benzoxazine described in US-P 3,951,660.
  • the recording layer may contain other additives such as free fatty acids, surface-active agents, antistatic agents, e.g. non-ionic antistatic agents including a fluorocarbon group as e.g. in F3C(CF2)6CONH(CH2CH2O)-H, ultraviolet light absorbing compounds, white light reflecting and/or ultraviolet radiation reflecting pigments, colloidal silica, and/or optical brightening agents.
  • antistatic agents e.g. non-ionic antistatic agents including a fluorocarbon group as e.g. in F3C(CF2)6CONH(CH2CH2O)-H
  • ultraviolet light absorbing compounds e.g. in F3C(CF2)6CONH(CH2CH2O)-H
  • white light reflecting and/or ultraviolet radiation reflecting pigments e.g. in colloidal silica, and/or optical brightening agents.
  • the above ingredients are present in a polymeric binder preferably on a flexible base.
  • thermoplastic resins are used wherein the ingredients can be dispersed homogeneously or form a solid-state solution.
  • all kinds of natural, modified natural or synthetic resins may be used, e.g. cellulose derivatives such as ethylcellulose, cellulose esters, carboxymethylcellulose, starch ethers, galactomannan, polymers derived from ⁇ , ⁇ -ethylenically unsaturated compounds such as polyvinyl chloride, after-chlorinated polyvinyl chloride, copolymers of vinyl chloride and vinylidene chloride, copolymers of vinyl chloride and vinyl acetate, polyvinyl acetate and partially hydrolyzed polyvinyl acetate, polyvinyl alcohol, polyvinyl acetals, e.g.
  • polyvinyl butyral copolymers of acrylonitrile and acrylamide, polyacrylic acid esters, polymethacrylic acid esters, polystyrene and polyethylene or mixtures thereof.
  • a particularly suitable ecologically interesting (halogen-free) binder is polyvinyl butyral.
  • Polyvinyl butyral containing some vinyl alcohol units is marketed under the trade name BUTVAR B79 of Monsanto USA.
  • the binder to organic silver salt ratio is preferably in the range of 0.2 to 6, and the thickness of the imaging, called recording layer, is preferably in the range of 5 to 16 ⁇ m.
  • the above mentioned polymers or mixtures thereof forming the binder may be used in conjunction with waxes or "heat solvents” also called “thermal solvents” or “thermosolvents” improving the reaction speed of the redox-reaction at elevated temperature.
  • heat solvents also called “thermal solvents” or “thermosolvents” improving the reaction speed of the redox-reaction at elevated temperature.
  • heat solvent in this invention is meant a non-hydrolyzable organic material which is in solid state in the recording layer at temperatures below 50 °C but becomes a plasticizer for the recording layer in the heated region and/or liquid solvent for at least one of the redox-reactants, e.g. the reducing agent for the organic silver salt, at a temperature above 60 °C.
  • redox-reactants e.g. the reducing agent for the organic silver salt
  • the recording materials of the present invention are particularly suited for use in thermographic recording techniques operating with thermal print-heads.
  • Suitable thermal printing heads are e.g. a Fujitsu Thermal Head (FTP-040 MCS001), a TDK Thermal Head F415 HH7-1089, and a Rohm Thermal Head KE 2008-F3.
  • the imagewise heating of the recording layer with said printheads proceeds through a contacting but removable resin sheet or web wherefrom during said heating no transfer of imaging material can take place.
  • the base or support of the heat-sensitive recording material according to the present invention may be transparent, translucent or opaque and is preferably a thin flexible carrier made e.g. from paper, polyethylene coated paper or transparent resin film, e.g. made of a cellulose ester, e.g. cellulose triacetate, polypropylene, polycarbonate or polyester, e.g. polyethylene terephthalate.
  • the support may be in sheet, ribbon or web form and subbed if need be to improve the adherence to the thereon coated heat-sensitive recording layer.
  • the support may be made of an opacified resin composition, e.g.
  • the coating of the heat-sensitive recording layer may proceed by any coating technique e.g. as described in Modern Coating and Drying Technology, edited by Edward D. Cohen and Edgar B. Gutoff, (1992) VCH Publishers Inc. 220 East 23rd Street, Suite 909 New York, NY 10010, U.S.A.
  • thermographic recording material according to the present invention is prepared and tested as described hereinafter.
  • a subbed polyethylene terephthalate support having a thickness of 100 ⁇ m was doctor blade-coated so as to obtain thereon after drying the following recording layer A including : silver behenate 5 g/m2 polyvinyl butyral 2.5 g/m2 behenic acid 0.46 g/m2 indane I 0.95 g/m2 3,4-dihydro-2,4-dioxo-1,3,2H-benzoxazine 0.36 g/m2 silicone oil 0.02 g/m2
  • the recording layer B contained 0.61 g/m2 of pyrocatechol (1,2-dihydroxybenzene, and recording layer C contained 0.61 g/m2 of hydroquinone (1,4-dihydoxybenzene) instead of said indane I.
  • part P of the thus coated recording materials A, B and C was kept for 3 days at 20 °C (room temperature) and relative humidity (R.H.) of 60 %, and another part (part Q) was kept for the same period at 57 °C and R.H. of 34 %.
  • the still very low minimum density in the recording layer part Q of invention material A that had been subjected to the defined thermal pre-treatment proves the very good stability of the present recording layer by means of which still an optical density of almost 4 can be obtained in areas heated by said thermal printhead recorder (operating at a temperature well above 100 °C).
  • thermographic recording material according to the present invention is prepared and exposed with infrared (IR) laser beam as described hereinafter.
  • IR infrared
  • a subbed polyethylene terephthalate support having a thickness of 100 ⁇ m was doctor blade-coated from a methyl ethylketone coating solution so as to obtain thereon after drying the following recording layer including : silver behenate 1.65 g/m2 polyvinyl butyral 0.820 g/m2 behenic acid 0.165 g/m2 indane 1 0.300 g/m2 3,4-dihydro-2,4-dioxo-1,3,2H-benzoxazine 0.120 g/m2 component 1 (see structure hereinafter) 0.19 g/m2 component 2 (see structure hereinafter) 0.29 g/m2
  • Component 1 and 2 together form an infrared light absorbing complex.
  • the absorption (density) of the dried layer was 0.72 at 1053 nm.
  • the recording material was exposed by means of a Nd-YLF (yttrium lithium fluoride) laser emitting at 1053 nm (spot diameter 18 ⁇ m; laser power striking the film : 1.60 W; writing time for A3 format : 24 min).
  • Nd-YLF yttrium lithium fluoride
  • the optical density in the laser-exposed areas measured as in Example 1 was : 0.47.
  • Component 1 has the following structural formula :
  • Component 2 has the following structural formula :
EP19930203120 1992-11-16 1993-11-08 Wärmeempfindliches Aufzeichnungsmaterial Expired - Lifetime EP0599369B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP19930203120 EP0599369B1 (de) 1992-11-16 1993-11-08 Wärmeempfindliches Aufzeichnungsmaterial

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EP92203495 1992-11-16
EP92203495 1992-11-16
EP19930203120 EP0599369B1 (de) 1992-11-16 1993-11-08 Wärmeempfindliches Aufzeichnungsmaterial

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EP0599369A1 true EP0599369A1 (de) 1994-06-01
EP0599369B1 EP0599369B1 (de) 1997-02-19

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0685760A1 (de) * 1994-05-30 1995-12-06 Agfa-Gevaert N.V. Wärmeempfindliches Aufzeichnungsmaterial
EP0739748A1 (de) * 1995-04-20 1996-10-30 Minnesota Mining And Manufacturing Company Durch Laser direkt beschreibbare Auzeichnungsmaterialien
US5573995A (en) * 1993-04-27 1996-11-12 Agfa-Gevaert Method for making an image using a direct thermal imaging element
GB2305509A (en) * 1995-09-19 1997-04-09 Minnesota Mining & Mfg Heat sensitive elements
US5863859A (en) * 1994-05-30 1999-01-26 Agfa-Gevaert N.V. Heat-sensitive material suited for use in direct thermal recording
US5948600A (en) * 1993-09-13 1999-09-07 Agfa-Gevaert N.V. Method and material for the formation of a heat mode image
US6677274B2 (en) 2000-05-25 2004-01-13 Agfa-Gevaert Thermographic recording material with improved image tone
DE102012017010A1 (de) 2012-08-28 2012-10-31 Heidelberger Druckmaschinen Ag Immonium-Absorber für Druckfarben und Lacke

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3031329A (en) * 1959-10-26 1962-04-24 Minnesota Mining & Mfg Heat-sensitive copy-sheet and composition therefor
FR2225771A1 (de) * 1973-04-16 1974-11-08 Agfa Gevaert

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3031329A (en) * 1959-10-26 1962-04-24 Minnesota Mining & Mfg Heat-sensitive copy-sheet and composition therefor
FR2225771A1 (de) * 1973-04-16 1974-11-08 Agfa Gevaert

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5573995A (en) * 1993-04-27 1996-11-12 Agfa-Gevaert Method for making an image using a direct thermal imaging element
US5948600A (en) * 1993-09-13 1999-09-07 Agfa-Gevaert N.V. Method and material for the formation of a heat mode image
EP0685760A1 (de) * 1994-05-30 1995-12-06 Agfa-Gevaert N.V. Wärmeempfindliches Aufzeichnungsmaterial
US5863859A (en) * 1994-05-30 1999-01-26 Agfa-Gevaert N.V. Heat-sensitive material suited for use in direct thermal recording
EP0739748A1 (de) * 1995-04-20 1996-10-30 Minnesota Mining And Manufacturing Company Durch Laser direkt beschreibbare Auzeichnungsmaterialien
GB2305509A (en) * 1995-09-19 1997-04-09 Minnesota Mining & Mfg Heat sensitive elements
US5766828A (en) * 1995-09-19 1998-06-16 Imation Corp. Laser addressable imaging elements
US6677274B2 (en) 2000-05-25 2004-01-13 Agfa-Gevaert Thermographic recording material with improved image tone
DE102012017010A1 (de) 2012-08-28 2012-10-31 Heidelberger Druckmaschinen Ag Immonium-Absorber für Druckfarben und Lacke

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