Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
  • B41M5/382—Contact thermal transfer or sublimation processes
  • B41M5/385—Contact thermal transfer or sublimation processes characterised by the transferable dyes or pigments
  • B41M5/3854—Dyes containing one or more acyclic carbon-to-carbon double bonds, e.g., di- or tri-cyanovinyl, methine
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/50—Recording sheets characterised by the coating used to improve ink, dye or pigment receptivity, e.g. for ink-jet or thermal dye transfer recording
  • B41M5/52—Macromolecular coatings
  • B41M5/5227—Macromolecular coatings characterised by organic non-macromolecular additives, e.g. UV-absorbers, plasticisers, surfactants

Definitions

• This invention relates to merocyanine dye-donor elements used in thermal dye transfer which have high maximum dye densities.
• thermal transfer systems have been developed to obtain prints from pictures which have been generated electronically from a color video camera.
• an electronic picture is first subjected to color separation by color filters.
• the respective color-separated images are then converted into electrical signals.
• These signals are then operated on to produce cyan, magenta and yellow electrical signals.
• These signals are then transmitted to a thermal printer.
• a cyan, magenta or yellow dye-donor element is placed face-to-face with a dye-receiving element.
• the two are then inserted between a thermal printing head and a platen roller.
• a line-type thermal printing head is used to apply heat from the back of the dye-donor sheet.
• the thermal printing head has many heating elements and is heated up sequentially in response to the cyan, magenta and yellow signals. The process is then repeated for the other two colors. A color hard copy is thus obtained which corresponds to the original picture viewed on a screen. Further details of this process and an apparatus for carrying it out are contained in U. S. Patent No. 4,621,271 by Brownstein entitled “Apparatus and Method for Controlling A Thermal Printer Apparatus,” issued November 4, 1986.
• Japanese Patent Publication 60/214994 relates to cyanine or merocyanine dyes which are used in an image recording material. Those dyes, however, are not used in a thermal dye transfer system. Instead, those dyes are light bleachable, such as by flash exposure, to bleach or destroy the dye. Thus, those dyes undergo substantial photolysis or decomposition when exposed to radiant energy. In addition, those dyes absorb at wavelengths substantially beyond the visible spectrum, unlike the dyes of the present invention.
• a dye-donor element comprising a support having thereon a dye layer characterized in that the dye comprises a merocyanine dye dispersed in a polymeric binder, the merocyanine dye being capable of transfer by diffusion to dye-receiving element upon the application of heat and being incapable of substantial photolysis, the merocyanine dye being substituted or unsubstituted on the bridging methine carbon atoms.
• the dyes of the invention are "incapable of substantial photolysis” is meant that the dyes of the invention do not undergo any substantial decomposition when exposed to radiant energy.
• the merocyanine dyes employed in the invention may be of cyan, magenta or yellow hue.
• the merocyanine dye has the formula: wherein: A represents -COR, -COOR, -CONHR, -CN, -SO2R or -SO2NR2; or A may be combined together with R1 to form a heterocyclic or carbocyclic ring system such as R1 represents -NHR, -NR2, -OR, -SR, or -R; n represents 0 or 1; Z represents the atoms necessary to complete a 5- or 6-membered substituted or unsubstituted heterocyclic ring such as 3H-indole, benzoxazole, thiazoline, benzimidazole, oxazole, thiazole; and each R independently represents a substituted or unsubstituted alkyl group of from 1 to 6 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl or such alkyl
• a and R1 in the above formula are combined together to form the following ring system: wherein R2 is CH3 or C6H5; R3 is CH3, H or COOC2H5; and n is 0.
• a and R1 in the above formula are combined together to form the following ring system: and n is 0.
• A is -CN, n is 0 and R1is phenyl or an alkyl group of from 1 to 6 carbon atoms.
• a dye-barrier layer comprising a hydrophilic polymer may be employed in the dye-donor element of the invention between its support and the dye layer to improve the density of the transferred dye.
• the dye in the dye-donor element of the invention is dispersed in a polymeric binder such as a cellulose derivative, e.g., cellulose acetate hydrogen phthalate, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, cellulose triacetate; a polycarbonate; poly(styrene-co-acrylonitrile), a poly(sulfone) or a poly(phenylene oxide).
• the binder may be used at a coverage of from 0.1 to 5 g/m2.
• the dye layer of the dye-donor element may be coated on the support or printed thereon by a printing technique such as a gravure process.
• any material can be used as the support for the dye-donor element of the invention provided it is dimensionally stable and can withstand the heat of the thermal printing heads.
• Such materials include polyesters such as poly(ethylene terephthalate); polyamides; polycarbonates; glassine paper; condenser paper; cellulose esters; fluorine polymers; polyethers; polyacetals; polyolefins; and polyimides.
• the support generally has a thickness of from 2 to 30 ⁇ m. It may also be coated with a subbing layer, if desired.
• the reverse side of the dye-donor element may be coated with a slipping layer to prevent the printing head from sticking to the dye-donor element.
• a slipping layer would comprise a lubricating material such as a surface active agent, a liquid lubricant, a solid lubricant or mixtures thereof, with or without a polymeric binder.
• the dye-receiving element that is used with the dye-donor element of the invention usually comprises a support having thereon a dye image-receiving layer.
• the support may be a transparent film such as a poly(ether sulfone), a polyimide, a cellulose ester such as cellulose acetate, a poly(vinyl alcohol-co-acetal) or a poly(ethylene terephthalate).
• the support for the dye-receiving element may also be reflective such as baryta-coated paper, polyethylene-coated paper, white polyester (polyester with white pigment incorporated therein), an ivory paper, a condenser paper or a synthetic paper such as duPont Tyvek®. In a preferred embodiment, polyester with a white pigment incorporated therein is employed.
• the dye image-receiving layer may comprise, for example, a polycarbonate, a polyurethane, a polyester, polyvinyl chloride, poly(styrene- co -acrylo­nitrile), poly(caprolactone) or mixtures thereof.
• the dye image-receiving layer may be present in any amount which is effective for the intended purpose. In general, good results have been obtained at a concentration of from 1 to 5 g/m2.
• the dye-donor elements of the invention are used to form a dye transfer image.
• Such a process comprises imagewise-heating a dye-donor element as described above and transferring a dye image to a dye-receiving element to form the dye transfer image.
• the dye-donor element of the invention may be used in sheet form or in a continuous roll or ribbon. If a continuous roll or ribbon is employed, it may have only the dye thereon as described above or may have alternating areas of other different dyes, such as sublimable cyan, yellow, magenta and/or black or other dyes. Such dyes are disclosed in U.S. Patent 4,541,830. Thus, one-, two-, three- or four-color elements (or higher numbers also) are included within the scope of the invention.
• the dye-donor element comprises a poly(ethylene terephthalate) support coated with sequential repeating areas of cyan, magenta and yellow dye, at least one of the dyes being a merocyanine dye as described above, and the above process steps are sequentially performed for each color to obtain a three-color dye transfer image.
• the process is only performed for a single color, then a monochrome dye transfer image is obtained.
• a thermal dye transfer assemblage of the invention comprises
• the above assemblage comprising these two elements may be preassembled as an integral unit when a monochrome image is to be obtained. This may be done by temporarily adhering the two elements together at their margins. After transfer, the dye-receiving element is then peeled apart to reveal the dye transfer image.
• the above assemblage is formed on three occasions during the time when heat is applied by the thermal printing head. After the first dye is transferred, the elements are peeled apart. A second dye-donor element (or another area of the donor element with a different dye area) is then brought in register with the dye-receiving element and the process repeated. The third color is obtained in the same manner.
• a yellow dye-donor element was prepared by coating the following layers in the order recited on a 6 ⁇ m poly(ethylene terephthalate) support:
• a dye-receiving element was prepared by coating a solution of Makrolon 5705® (Bayer AG Corporation) polycarbonate resin (2.9 g/m2 in a methylene chloride and trichloroethylene solvent mixture on an ICI Melinex 990® white polyester support.
• the dye side of the dye-donor element strip 0.75 inches (19 mm) wide was placed in contact with the dye image-receiving layer of the dye-receiver element of the same width.
• the assemblage was fastened in the jaws of a stepper motor driven pulling device.
• the assemblage was laid on top of a 0.55 (14 mm) diameter rubber roller and a TDK Thermal Head (No. L-133) and was pressed with a spring at a force of 8.0 pounds (3.6 kg) against the dye-donor element side of the assemblage pushing it against the rubber roller.
• the imaging electronics were activated causing the pulling device to draw the assemblage between the printing head and roller at 0.123 inches/sec (3.1 mm/sec).
• the resistive elements in the thermal print head were pulse-heated at increments from 0 to 8.3 msec to generate a graduated density test pattern.
• the voltage supplied to the print head was approximately 22v representing approximately 1.5 watts/dot (12 mjoules/dot) for maximum power.
• the dye-receiving element was separated from the dye-donor element and the status A blue reflection density at the maximum density was read. The following results were obtained:
• Example 2 was repeated except that magenta dyes 44-46 and 48-50 were employed and the Green Status A maximum density was measured. The following results were obtained:
• Example 2 was repeated except that cyan dyes 51-53 were employed and the Red status A maximum density was measured. The following results were obtained.

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• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Thermal Transfer Or Thermal Recording In General (AREA)

Applications Claiming Priority (6)

Publications (3)

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Family Applications (1)

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Cited By (8)

Citations (5)

• 1987
  • 1987-07-28 CA CA000543131A patent/CA1268942A/en not_active Expired - Fee Related
  • 1987-08-21 DE DE8787112148T patent/DE3778793D1/de not_active Expired - Fee Related
  • 1987-08-21 EP EP87112148A patent/EP0257580B1/de not_active Expired - Lifetime

Patent Citations (5)

Non-Patent Citations (1)

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