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
  • B41M5/38207—Contact thermal transfer or sublimation processes characterised by aspects not provided for in groups B41M5/385 - B41M5/395
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/315—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material
  • B41J2/32—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material using thermal heads
  • B41J2/325—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material using thermal heads by selective transfer of ink from ink carrier, e.g. from ink ribbon or sheet
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/315—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material
  • B41J2/38—Preheating, i.e. heating to a temperature insufficient to cause printing

Definitions

• the present invention relates to improvements in transfer printing, particularly to improvements in thermal transfer printing, which increase print energy efficiency and print quality.
• absorber is arranged in a transfer printing medium such that it absorbs applied energy necessary for the transfer of indicia-forming material preferably without degrading quality and/or color characteristics of the printed
• the efficiency, speed and range of printing energy suppliers available for transfer printing is increased by heating a transfer printing medium prior to or during the application of print energy.
• Transfer printing is a generic term for processes in which one or more print indicia materials (i.e., dyes, dispersions, colorants, etc.) are caused to transfer from one medium to a receiver surface in response to an external stimulus. See U.S. Patent No. 4,614,521, U.S. Patent No. 4,657,557, U.S. Patent No. 4,748,151, U.S. Patent No.
• thermal transfer printing wherein thermally transferable dyes are caused to transfer from a medium such as a
• dyesheet to, e.g., a piece of paper.
• thermal transfer printing has been used in the past for printing woven and knitted textiles and various other rough materials by placing over the material to be printed on a sheet carrying the desired pattern in the form of sublimable dyes.
• Common commercial forms of such materials are "iron-on" images popular for children's clothes.
• thermal transfer printing process is one used to produce indicia on a surface, typically a piece of coated or plain paper, using pixel printing equipment including thermal energy sources such as thermal pin printers, or light energy sources including laser beams, etc whose energy is converted to thermal energy when absorbed.
• the print energy source thermal print head, laser printer, etc.
• the print energy source is controlled by
• the pattern to be printed need not be pre-formed on a print medium such as a dyesheet, and a medium is used which typically comprises a thin substrate supporting at least one transfer coat having single or multiple print indicia materials (dyes, dispersions, etc.) contained therein and forming, typically, a continuous and uniform layer over an entire printing area of the medium.
• a print medium such as a dyesheet
• a medium typically comprises a thin substrate supporting at least one transfer coat having single or multiple print indicia materials (dyes, dispersions, etc.) contained therein and forming, typically, a continuous and uniform layer over an entire printing area of the medium.
• Examples of printing techniques using such media include thermal wax printing, sublimation dye printing, dye diffusion thermal transfer printing, dye transfer printing, etc.
• print media include printing ribbons such as those commonly used in office products to carry coloring materials onto a receiver sheet.
• Printing is typically effected by heating selected discrete areas of the medium, e.g., dyesheet, while the transfer coat is held against a dye-receptive surface such as coated or plain paper, causing a colorant, e.g., a dye, to transfer onto the corresponding areas of the receptive surface.
• the shape of the pattern transferred is determined by the number and location of areas which were subjected to heating, and the depth of the shade in any area is
• D2T2 printing dye diffusion thermal transfer printing
• thermal wax printing where a wax binder is melted and transferred, are also popular. All these printing methods are referred to herein “thermal printing” since printing requires thermal energy.
• print energy includes all energies that effect thermal printing, including heat, light, etc.
• printing ribbons generally are made from a sheet-like substrate such as paper, polymeric resins, etc. which support on one surface thereof a transfer coat containing a thermally transferable dye, typically
• Additional coating layers may also be present, including adhesive or dye-barrier sublayers between the substrate and transfer coat, and back coats on a second surface for improving slip or heat resistance properties. See, for example, the above list of U.S. patents incorporated herein by reference for examples of substrates, binders, dyes, etc. Such dyesheets may be elongated and/or housed in a cassette for
• Thermal transfer printing media designed for producing multicolored prints have a plurality of panels of different uniform colors, typically three or four, including yellow, magenta and cyan and sometimes black. When supported on a substrate elongated in the form of a ribbon these different panels may be provided as longitudinal parallel strips or as transverse panels, each the size of the desired print arranged in a repeated sequence of the color used. During printing, panels of each color are placed on or near the receiver sheet and energy is applied thereto by means of a thermal head, laser, etc., to effect transfer of the dye as required. The initial print indicia can be overprinted by a subsequent color to make up the full color spectrum.
• an energy absorber typically an IR energy absorber
• an energy absorber typically an IR energy absorber
• such energy absorbers which are typically chemical species, interfere with and change the color of the printed indicia by, e.g., interfering with the dye color. This contamination often makes it impossible to print true yellow, true magenta, true cyan, etc. and significantly impacts the application of transfer printing such as D2T2 printing.
• one object of this invention is to provide a novel transfer printing medium which includes an energy absorber which does not interfere with the printed characteristics, especially the color, of the dye,
• colorant dispersion, etc. (hereinafter referred to as colorant) transferred therefrom during printing.
• Another object of the present invention is to provide a transfer printing method in which the amount of energy required to be supplied from the print head to effect transfer printing is decreased.
• Another object of the present invention is to provide a transfer printing method wherein a laser beam is used as a print head to supply the print energy necessary to effect transfer of colorant from a transfer printing medium to a receiver surface.
• Figure 1 depicts three separate embodiments of the first aspect of the present invention wherein a transfer printing medium is provided comprising a base film having arranged thereon a separate transfer coating layer
• Figure 2 shows a second aspect of the present
• a transfer printing medium such as a print ribbon is pre-heated prior to the application of print energy from e.g., a laser or thermal head, to effect printing.
• a thermal transfer printing medium comprising a
• the substrate according to the present invention can be any substrate typically used in the printing art, including paper, polymeric resins, etc., and is typically formed in the shape of a sheet, a ribbon, etc. See the list of U.S. patents referred to above for examples. Size and thickness of the present invention substrate is not limited. Thermoplastic films such as mylar, etc. are particularly preferred, but the present invention includes any and all substrates useful for supporting a transfer coat and capable of containing or supporting a print energy absorber. Preferred substrates are those typically used in printing processes such as thermal transfer printing, etc.
• the present invention substrate supports a transfer coat which contains a colorant to be transferred to a receiving surface so as to form an indicia, including images, etc.
• the transfer coat contains a dye, preferably a dye useful in thermal transfer printing such as D2T2 printing, etc., particuarly those described in the above-referenced U.S. patents, but may instead contain a dispersion, etc. which can be transferred to a receiver surface by the application of energy, preferably thermal energy (including laser energy). See the U.S. patents listed above for examples of print energy suppliers.
• the transfer coat according to the present invention typically further comprises a binder in which the dye, dispersion, etc. is contained. Any binder may be used, including cellulosic polymers, polyvinylbutyral, etc. See the U.S. patents listed above for examples.
• the print energy absorber according to the present invention is any material which is capable of absorbing the print energy applied to a thermal transfer printing medium to effect printing.
• Such energy absorbers are typically IR absorbers, laser energy absorbers, thermal energy
• absorbers etc. and include all substances which absorb the print energy applied to the transfer printing medium so as to effect printing. See the U.S. patents and publications above for examples.
• the components of the thermal transfer printing medium are arranged such that the energy absorber is not contained within the transfer coat at all and/or in such a manner that the printed color of the colorant indicia forming material therein (dyes, dispersions, etc.) is affected when printed on a surface.
• the print energy absorber is arranged such that it is in a separate layer arranged beneath the transfer coat, typically on a surface of the substrate opposite the surface with the transfer coat. See Figure la.
• the present invention transfer printing medium includes a substrate which itself incorporates the print energy absorber. On the substrate is contained the transfer coat. See Figure lb.
• the energy absorber is arranged in a separate layer and underneath the transfer coat. See Figure 1C.
• Additional barrier layers to prevent intermixing of the print energy absorber and the transfer coat can be used, as well as other layers, materials, etc. generally known in the art for thermal print media. See the above- listed U.S. patents for examples of such additives, etc.
• the print energy absorber may itself be dispersed within a binder, etc., and form a separate layer on the substrate, or may be dispersed within the substrate layer. See the U.S. patents listed above for examples of binders,
• the print energy absorber is arranged such that it is not contained within the transfer coat in such a manner that it affects the printed properties, particularly the color printed properties, of the colorant indicia-forming material contained within the transfer coat.
• the transfer coat contains no print energy absorbers.
• transfer printing is increased by heating the transfer coat of a thermal transfer printing medium prior to and/or during (meaning concomitant with) printing by, e.g., a thermal head or a laser beam. See Figure 2A for laser beam printing, and Figure 2B for thermal head printing. Any type of separate (i.e., separate from the print energy source) heating can be used. Heating can occur as in
• FIG. 2 can occur at the point where print energy is applied, etc. including combinations thereof.
• Any type of thermal transfer printing in which colorant is transferred to a receiving surface by heat, laser energy, etc. is included in this aspect of the present invention, and the separate heating (i.e., heating by means other than the print energy means such as a thermal head, etc.) of the transfer printing medium can occur to any extent desired up until the transfer printing medium is not suitable for printing due to, e.g., melted binder in the transfer coat, etc.
• laser print energy in thermal printing especially in a D2T2 recording environment, is practical, as it is for all thermal transfer systems.
• Lasers providing power of, e.g., 0.3 - 24W, preferably 0.3 - 12W, 0.5 - 4W, and 12 - 24W, can be used to print at speeds of, e.g., 1 page per minute. See Table 1 below for several minimum energy requirements for different recording methods. In view of the second aspect of the present invention, these minimum energy requirements now can be applied to the transfer printing medium not only by the indicia-forming print energy supplier in the form of a thermal head, a laser beam, etc., but can be supplied by a combination of a separate heating element and a traditional indicia-forming energy supplier (printhead, laser beam, etc.).
• the method and manner of separately heating the thermal transfer printing medium according to the invention is not particularly limited herein. Instead, any kind of heating means (element) including a resistance heater, hot air blower, IR heater, radiant lamp, etc. all can be used to heat the transfer printing medium before or while print indicia-forming energy is applied thereto. Heating can be applied to the thermal transfer medium before it reaches the print area and/or while it is at the print area.
• any kind of heating means including a resistance heater, hot air blower, IR heater, radiant lamp, etc. all can be used to heat the transfer printing medium before or while print indicia-forming energy is applied thereto. Heating can be applied to the thermal transfer medium before it reaches the print area and/or while it is at the print area.
• the transfer printing medium can contain a thermal energy absorber and an absorber to absorb print energy if these two energies are different.
• Both embodiments of the present invention can be used with all existing thermal transfer printing methods and media including the several methods, thermal transfer dyesheets, etc. described in the U.S. Patents listed above and incorporated herein by reference and U.S. Patents
• the second embodiment of the present invention is particularly advantageous when the primary print energy-supplying source for forming indicia (i.e., printing) is a laser source and the thermal transfer printing medium is a direct dye thermal transfer medium such as a dyesheet or ribbon.
• the thermal transfer printing medium is a direct dye thermal transfer medium such as a dyesheet or ribbon.
• D2T2 printing was accomplished using a 0.8W laser as the print energy source and a
• a transfer sheet (Mitsubishi Chemical) consisting of a layer of carbon black (serving as the print energy absorber) sandwiched between a transfer coat (containing an IR absorber and colorant) and substrate was used.
• the comparative IR-enhanced transfer sheet was the same but had no carbon black layer. See Figure 1C. Pre-heating was accomplished with hot air. Results obtained are described in Table 2 below:
• the IR enhanced ribbon prints a greenish color instead of a yellow color without the invention energy absorber due to the IR energy-absorber contained in the transfer coating layer which interferes with the dye.
• the same ribbon prints yellow when configured according to the present invention and having a energy absorbing layer as a backing layer. This indicates that IR-enhanced ribbons, which are the current state of the art, can be improved according to the present invention.
• IR-enhancers will no longer be added to the transfer coat in a manner that allows them re interfere with the dye.

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

Priority Applications (3)

Applications Claiming Priority (4)

Publications (2)

Family

ID=27061117

Family Applications (1)

Country Status (4)

Cited By (3)

Citations (7)

• 1996
  • 1996-09-03 JP JP9512708A patent/JPH11512359A/ja active Pending
  • 1996-09-03 EP EP96930615A patent/EP0848667A4/en not_active Withdrawn
  • 1996-09-03 WO PCT/US1996/013813 patent/WO1997010956A1/en not_active Application Discontinuation
  • 1996-09-03 AU AU69595/96A patent/AU6959596A/en not_active Abandoned

Patent Citations (7)

Non-Patent Citations (1)

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