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
  • B41M5/40—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used characterised by the base backcoat, intermediate, or covering layers, e.g. for thermal transfer dye-donor or dye-receiver sheets; Heat, radiation filtering or absorbing means or layers; combined with other image registration layers or compositions; Special originals for reproduction by thermography
  • B41M5/42—Intermediate, backcoat, or covering layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M2205/00—Printing methods or features related to printing methods; Location or type of the layers
  • B41M2205/30—Thermal donors, e.g. thermal ribbons
• • 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
  • B41M5/40—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used characterised by the base backcoat, intermediate, or covering layers, e.g. for thermal transfer dye-donor or dye-receiver sheets; Heat, radiation filtering or absorbing means or layers; combined with other image registration layers or compositions; Special originals for reproduction by thermography
  • B41M5/42—Intermediate, backcoat, or covering layers
  • B41M5/426—Intermediate, backcoat, or covering layers characterised by inorganic compounds, e.g. metals, metal salts, metal complexes
• • 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
  • B41M5/40—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used characterised by the base backcoat, intermediate, or covering layers, e.g. for thermal transfer dye-donor or dye-receiver sheets; Heat, radiation filtering or absorbing means or layers; combined with other image registration layers or compositions; Special originals for reproduction by thermography
  • B41M5/42—Intermediate, backcoat, or covering layers
  • B41M5/44—Intermediate, backcoat, or covering layers characterised by the macromolecular compounds

Definitions

• the invention relates to a thermal ink ribbon, in particular thermocarbon ribbon, with a conventional carrier and a layer of a melting ink formed on one side of the carrier, a separating layer being located between the carrier and the layer of the melting ink, and a method which is particularly suitable for the production thereof.
• Thermal ribbons have long been known, they have a melting color on a film-like carrier, for example made of paper, a plastic or the like, in particular in the form of a plastic and / or wax-bound colorant or carbon black layer.
• the melting ink is melted by means of a thermal print head and transferred to a recording paper or a printing paper.
• Thermal printers or thermal print heads that can be used for this process are e.g. B. from DE-ASen 2 062 494 and 2 406 613 and DE-OS 3 224 445 known.
• z. B. proceed as follows: A letter consisting of heated dots and to be printed on a sheet of paper is formed on the thermal print head of the printer. The thermal print head presses the thermal ribbon onto the paper to be written on.
• the heated letter of the thermal print head at a temperature of about 400 ° C leads to the melting ink being melted at the heated point and being transferred to the paper sheet in contact with it.
• the used part of the thermal ribbon is fed to a spool.
• the thermal ribbon can have different melting colors next to each other. With the combination of the basic colors blue, yellow and red, colored print images can be produced. Compared to the usual color photographs, there is no disadvantageous development and fixing. Thermal printers can be operated at high writing speeds (a DIN A4 sheet can be printed in about 10 seconds) and without annoying background noises.
• thermal ribbons described above there are also those in which the heat symbol is not embossed by the action of a thermal print head, but by resistance heating of a specially designed film-like carrier.
• the heat is generated by the flow of an electric current, for this purpose the melting ink and / or its support must contain electrically conductive materials.
• the melting color which represents the actual functional layer during the printing process, also contains the materials already described above.
• ETR Electro Thermal Ribbon
• a corresponding thermal transfer printing system is described, for example, in US Pat. No. 4,309,117.
• European patent application 86 301 743 (publication no .: 0 194 860) suggests arranging a meltable "release layer" between a plastic-bound melting ink and its carrier material, which preferably contains a wax as the main component.
• the disadvantage of this system is that it cannot be used with advantage for those thermal ribbons in which the melting ink is wax-bound.
• the invention was therefore based on the object of developing the thermal ink ribbon described at the outset in such a way that easy and complete removal of the melting ink during the printing process is possible regardless of whether the melting ink is wax and / or plastic-bound.
• the separating layer contains water-releasing agents dispersed in a binder.
• the temperature under the thermal printing conditions must be sufficient to release at least part of the water contained or bound in the water-releasing agent, so that the separating layer acquires a hydrophilic character during the printing process.
• a temperature of about 50 to 400 ° C can trigger these desirable effects.
• the temperature in the pressure conditions is in the upper part of the temperature range described above.
• the percentage by weight of the water-releasing agent in the separating layer is not of critical importance for the invention. The only thing that matters here is that a comparatively small amount of water is released during the printing process in order to give the separating layer the desirable hydrophilic character.
• a weight percentage range of preferably about 10 to 80 could be considered.
• a wide variety of compounds are suitable as water-releasing agents.
• Organic and inorganic compounds containing water of crystallization such as alums, borax, Glauber's salt, zeolites, citric acid and / or oxalic acid, are used with particular advantage.
• the compounds with particularly high crystal water content have proven to be advantageous, such as in particular alums, such as. B. aluminum, iron and chrome alum and borax.
• Water-soluble organic binders are advantageously used, in particular polyvinylpyrrolidone, polyvinyl acetate, methyl cellulose, water-soluble starch, water-soluble starch derivatives, casein, polyvinyl alcohol and the like.
• the thickness of the separating layer is also not critical for the effect sought with the invention. It can be subject to wide fluctuations. It is preferably about 0.1 to 2 micrometers, very particularly preferably 0.5 to 1.0 micrometers. In view of the expenditure and the fact that the desired effect is already achieved with the thinnest layers, work should be carried out as close as possible to the minimum value within the range described above.
• the thermal ink ribbon according to the invention can advantageously be produced as follows: one or more of the binders described above are transferred together with the water-releasing agent into an aqueous solution. It should preferably be about 40 to 60 parts by weight of binder to about 40 to 60 parts by weight of water-releasing agent.
• the application is carried out using a conventional technology, for example using a doctor blade.
• the separating layer remains within the scope of the layer thickness described above.
• the evaporation is preferably carried out by passing warm air at a temperature of about 80 to 120 ° C.
• a material is used with a doctor blade to form the separating layer in accordance with the following recipe: 0.5 part by weight of borax, 0.5 part by weight of polyvinylpyrrolidone, 3.0 parts by weight of water and 1.0 part by weight Ethanol. This material is applied in a dry thickness of approximately 0.2 micrometers.
• the water is evaporated by passing hot air at a temperature of around 110 ° C.
• the melting ink is applied using the following recipe in the form of a melt at a temperature of approximately 105 ° C. using a flexographic printing unit: 40 parts by weight of ethylene-vinyl acetate copolymer, 40 parts by weight of paraffin and 20 parts by weight of carbon black.
• the melting ink had a thickness of about 4 micrometers.
• this thermal ink ribbon showed a complete and easy detachment of the melting ink at the location of the embossed heat symbol.
• Example 1 was modified in such a way that the following recipe was used to form the separating layer: 0.5 part by weight of oxalic acid, 0.5 part by weight of polyvinylpyrrolidone, 3.0 parts by weight of water and 1.0 part by weight of ethanol.

Landscapes

• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Thermal Transfer Or Thermal Recording In General (AREA)
• Impression-Transfer Materials And Handling Thereof (AREA)
• Materials For Medical Uses (AREA)
• Artificial Filaments (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (3)

Family

ID=6359626

Family Applications (1)

Country Status (5)

Families Citing this family (3)

Family Cites Families (15)

• 1988
  • 1988-07-27 DE DE3825438A patent/DE3825438A1/de active Granted
• 1989
  • 1989-07-07 EP EP89112424A patent/EP0352525B1/de not_active Expired - Lifetime
  • 1989-07-07 DE DE8989112424T patent/DE58904121D1/de not_active Expired - Fee Related
  • 1989-07-07 AT AT89112424T patent/ATE88416T1/de not_active IP Right Cessation
  • 1989-07-26 US US07/553,794 patent/US5106217A/en not_active Expired - Lifetime
  • 1989-07-27 JP JP1192784A patent/JPH0775900B2/ja not_active Expired - Lifetime

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