JPH0466196B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a dye-donating layer used for dye thermal transfer,
More particularly, it relates to employing a particular slipping layer on the backside of the dye-donor element to prevent chatter marks and tearing of the dye-donor element during printing operations. In recent years, thermal transfer systems have been developed for obtaining prints from images produced electronically by color video cameras. According to one method of obtaining this type of print, the electrophotograph is first subjected to color separation using color filters. Each color-separated image is then converted into an electrical signal. These signals are then manipulated to obtain cyan, magenta and yellow electrical signals. These signals are then transmitted to a thermal printer. To obtain a print, a cyan, magenta, or yellow dye-donor element is placed opposite a dye-receiver element.
Both are then inserted between the thermal print head and the platen roller. Heat is applied from the back side of the dye-donor sheet using a linear thermal print head. The thermal print head includes a number of heating elements which are heated in response to sequential cyan, magenta and yellow signals. This process is then repeated for the other two colors. A color hard copy is thus obtained which corresponds to the current image seen on the screen. European Patent Application No. 169705 relates to a dye-donor element having a slipping layer on its back surface made of a compound having a perfluoroalkyl group or an ultraviolet curable resin. US Pat. No. 4,572,860 relates to a slipping layer made of urethane or vinyl chloride resin or higher fatty acids. There are problems with using dye-donor elements for dye thermal transfer. This is because a thin support is required for effective heat transfer. For example, if a thin polyester film is used, it will soften when heated during the printing operation and will stick to the thermal print head. This results in intermittent rather than continuous heat transfer over the thermal print head.
The pigment transferred in this way does not appear as a uniform area, but as a series of alternating light and dark bands (chatter marks).
appears as. Also, sufficient friction often occurs during printing operations to tear the dye-donor elements.
It would be desirable to eliminate problems of this type in order to obtain a commercially acceptable system. Another problem with many of the materials presented for use in dye thermal transfer printing is that they do not always have adequate performance. It is an object of the present invention to provide a slipping layer material for use in dye-donor elements that does not stick or tear when passed through a thermal head. These and other objects are characterized in that the lubricant is poly(vinyl stearate), poly(caprolactone), or a linear alkyl or polyethylene oxide perfluoroalkylated ester or ether,
This is achieved by the present invention, which comprises a dye-donor element for thermal dye transfer comprising a support having a dye layer on one side and a slipping layer of a lubricant dispersed in a high molecular weight binder on the other side. Poly(vinyl stearate) that can be used in the present invention is commercially available from Polysciences (No. 3169). Poly(caprolactone) that can be used in the present invention can include, for example, repeating units of the formula: where n is about 100 to about 600. This material is tone RCL-700 from Union Carbide
(TonePCL-700, registered trademark). The linear alkyl or polyethylene oxide perfluoroalkylated ester or perfluoroalkylated ether used in its preferred form in the present invention has the structure of the following formula. In this formula R ¹ is an alkyl group or substituted alkyl group having 1 to 6 carbon atoms, such as methyl, ethyl, butyl, isopropyl, 2-hydroxyethyl or 2-ethoxyethyl; or 6 to 10 carbon atoms. an aryl group or a substituted aryl group, such as phenyl, p-tolyl or p-methoxyphenyl; R ² is

[Formula] or _-CH2 -O-( _CH2 - _CH2 -O-) _z ^R3 ; ^R3 is H or ^R1 ; n is an integer from 4 to 20; and x and z are each independently an integer from 2 to 50. In a preferred form, R ¹ is ethyl and R ² is

[Formula], n is 8, and x' is 25-50. In another preferred form, ^R1 is ethyl, ^R2 is _-CH2 -O-(CH2 _{- CH2-} O-) _z'H , n is 8, and z' is 2- It is 30. Individual compounds within the scope of the above formula include: This substance is Fluorad (registered trademark)
It is commercially available as FC-431 (3M Company). This material is commercially available as Fluorad FC-170 (3M Company). Any high molecular weight binder can be used in the slipping layer of the present invention provided it has the desired effect.
For example, poly(vinyl alcohol-co-butyral) (commercially available as Butvar 76® by The Dow Chemical Company); polystyrene; poly(vinyl acetate); cellulose acetate butyrate; cellulose acetate; ethyl cellulose; bisphenols. A polycarbonate resin; poly(vinyl acetal); poly(vinyl benzal); cellulose triacetate; poly(methyl methacrylate); poly(styrene-co-acrylonitrile); poly(styrene-co-butadiene) and the like can be used. The lubricant used in the slipping layer of the present invention can be used in any amount effective for the intended purpose. Good results were generally obtained with a coating weight of 1 to 2000 mg/m ² . The high molecular weight binder used in the slipping layer in this invention is not critical. Generally, the high molecular weight binder represents 1 to 80% of the total layer coverage. In a preferred form of the invention, the high molecular weight binder in the slipping layer is poly(styrene coated).
Acrylonitrile). In another preferred form of the invention, the lubricant in the slipping layer is poly(vinyl stearate).
Consisting of Any dye can be used in the dye layer of the dye-donor element of this invention provided that it can be transferred to the dye-receiving layer by the action of heat. For example, the following sublimable dyes Particularly good results were obtained when using any of the dyes shown in US Pat. No. 4,541,830. The above dyes can also be used alone or in combination to obtain monochromatic images. The pigment is
It can be used at a coverage of 0.05 to 1 g/m ² and is preferably hydrophobic. A dye barrier layer can be used in the dye-donor elements of the invention to improve the density of the transferred dye. The dye in the dye-donor element is accompanied by a polymeric binder, such as cellulose derivatives such as cellulose acetate hydrogen phthalate, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, cellulose triacetate; polycarbonate; poly(styrene-
co-acrylonitrile), poly(sulfone) or poly(phenylene oxide). The binder can be used in a coverage of 0.1 to 5 g/m ² . The dye layer of the dye-donor element can be coated onto the support or printed onto the support by a printing method such as gravure. Any material can be used as the support for the dye-donor element of this invention, provided it is dimensionally stable and capable of withstanding the heat of the thermal printhead. Materials of this type include polyesters such as poly(ethylene terephthalate); polyamides; polycarbonates; glassine paper; capacitor paper; cellulose esters; fluoropolymers; polyethers; polyacetals; polyolefins and polyimides. The support generally has a thickness of 2 to 30 μm. This may be coated with an undercoat layer if desired. The dye-receiving element used with the dye-donor element of the present invention usually consists of a support carrying a dye image-receiving layer. The support may be, for example, a transparent film, such as poly(ethylene terephthalate), or reflective, such as baryta-coated paper or white polyester (polyester containing white facies). The dye image-receiving layer may be made of, for example, polycarbonate,
polyurethane, polyester, polyvinyl chloride,
It may consist of poly(styrene-co-acrylonitrile), poly(caprolactone) or mixtures thereof. As mentioned above, the dye-donor elements of the present invention are used in the form of dye transfer images. The method consists of image-wise heating the dye-donor element described above and transferring the dye image to the dye-receiving element to form a dye-transfer image. The dye-donor elements of this invention can be used in sheet form or in continuous roll or ribbon form. If a continuous roll or ribbon is used, it may carry only one type of dye, or it may contain different dyes, such as sublimable cyan, magenta, yellow, black, etc. (as shown in U.S. Pat. No. 4,541,830). may hold alternating areas of Thus, the scope of the present invention includes one-, two-, three- or four-color elements (or even more colors). In a preferred form of the invention, the dye-donor element consists of a poly(ethylene terephthalate) support coated with alternating regions of cyan, magenta and yellow dye, and each of the above processing steps is performed for each color sequentially, and the three A die transfer image is obtained. Of course, if this process is performed only for a single color, a single color dye transfer image will be obtained. Thermal print heads that can be used to transfer dye from the dye-donor elements of this invention are commercially available.
For example, Fujitsu Thermal Head (FTP-
040MCS001), TDK Thermal Head F415HH7
−1089, or Roam Thermal Head
KE2008-F3 can be used. A thermal dye transfer assembly using the present invention comprises a) a dye-donor element as described above, and b a dye-receiver element as described above, wherein the dye layer of the donor element is the dye image-receiving layer of the receiver element. is in superimposed relationship with the dye-donor element, in contact with the dye-donor element. The above assembly consisting of these two elements is
If a monochrome image is to be obtained, it can be preassembled as an integral unit. This is done by temporarily attaching the two elements to each other at their peripheries. After transfer, the dye-receiving element is peeled off to reveal the dye-transfer image. If a three-color image is to be obtained, the assembly described above is assembled three times during the period when heat is applied by the thermal print head. After the first dye has been transferred, these elements are peeled off. A second dye-donor element (or other area of the donor element containing a different dye area) is then aligned with the dye-receiver element and the process repeated. A third color is obtained in the same manner. The following examples are presented to illustrate the invention. Example 1 A magenta dye-donor element was prepared by coating the following layers in the following order onto a 6 μm poly(ethylene terephthalate) support. 1 Dye barrier layer of gelatin nitrate (gelatin,
Cellulose nitrate and salicylic acid, approximately 20:5:
2 weight ratio, solvent acetone, methanol and water) (0.17 g/ ^{m2 )} 2.
%, Phthalyl 32-36%) (0.39 g/m ² ), applied from 8% cyclohexanone in butanone: Poly(vinyl alcohol-co-butyral)
(Butovar 76) Table 1 in binder (0.43g/m ² )
A slipping layer containing the lubricant shown in (0.43 g/m ² ) was applied to the back side of the dye-donor element (applied from tetrahydrofuran solvent). The dye-receiving element was made of Makrolon 5705 (Bayer) polycarbonate resin (2.9 g/m ² ) in a dichloromethane and trichloroethylene or chlorobenzene solvent mixture.
It was prepared by coating the solution onto an ICI Melinex 990®, white polyester support. The dye side of each 0.75 inch (19 mm) wide strip of dye-donor elements was placed in contact with the image-receiving layer of a dye-receiver element of the same width. This assembly was secured to the jaw of a Stepper motor-driven tensioning device. This assemblage has a diameter of 0.55
Place it on top of an inch (14 mm) rubber roller and Fujitsu Thermal Head (FTP-040MCS001) and press the dye-donor side of the assembly against the rubber roller using a 3.5 pound (1.6 Kg) force spring. did. The imaging electronics were activated and a tensioner pulled the assembly between the printhead and the rollers at 0.123 inches/second (3.1 mm/second). Simultaneously, the resistor of the thermal print head was heated from 0 to 4.5 milliseconds in 0.5 millisecond (msec) increments to obtain a step density test pattern. The voltage applied to the printhead was approximately 19V, representing approximately 1.75W/dot. Estimated head temperature is
The temperature was 250-400℃. The assemblage through the thermal head was evaluated. If no tearing was observed, the assembly was disassembled, the dye-donor layer was discarded, and the dye transferred to the dye-receiver was visually evaluated. The following data were obtained.

【table】

The above data demonstrate that the materials used for the slipping layer in the present invention have unique efficacy in promoting smooth passage to the thermal head. Control materials either tore or gave only fair to poor performance. Example 2 Use of different binders Example 1 was repeated and poly(vinyl stearate) (0.43 g/m 2 ) was used as a lubricant in the high molecular weight binder (0.43 g/m ^{2 )} shown in Table 2. ) was used. The following results were obtained.

【table】

TABLE The above data show that various high molecular weight binders provide excellent or good performance when used with poly(vinyl stearate). The use of the slipping layer in the present invention results in dye-donor elements that do not stick or tear when passed through a thermal head.

Claims (1)

[Claims] 1. A dye-donor element for thermal transfer comprising a support having a dye layer on one side and a slipping layer consisting of a lubricant dispersed in a polymeric binder on the opposite side, wherein the lubricant is , 1 Poly(vinyl stearate); 2 Formula (wherein n is 100-600); or 3) a polyoxyalkylene ester of a perfluoroalkylsulfonamide-terminated carboxylic acid, or 2) a linear chain of a perfluoroalkylsulfonamide-terminated carboxylic acid. an alkyl ester, or (c) a polyoxyalkylated perfluoroalkylsulfonamide, and the perfluoroalkylsulfonamide has the formula In the formula, R ¹ is alkyl or substituted alkyl having 1 to 6 carbon atoms, or aryl or substituted aryl having 6 to 10 carbon atoms; R ² is or _-CH2 -O-( _CH2 - _CH2- O-) _z ^R3 (wherein, ^R3 is H or ^R1 ; n is an integer of 4-20; x and z are each independently 2-50 ), representing an integer of .