JPH06166196A - Thermal tranfer printing method and device - Google Patents

Abstract

PURPOSE:To perform thermal transfer printing on a rough substrate such as bond paper assuredly and maintain rough appearance and touch of the substrate itself in area where images are not printed. CONSTITUTION:A rough face 14 is coated with an image emphasizing precoat 30, a complete bridge is formed across a valley between adjacent peaks having rough faces, and the cavity of the valley is substantially removed. The colorant receive face of the coated image emphasizing precoat is coated with a colorant.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method and apparatus for monochromatic and color printing on various types of substrate surfaces, and more particularly to the thermal transfer of images or information onto a substrate such as paper (eg, , Thermal wax transfer, dye diffusion transfer, etc.).

[0002]

2. Description of the Related Art Thermal transfer printing includes known printing methods such as thermal wax transfer printing and thermal dye diffusion printing.

Thermal wax transfer prints are colorants (eg, magenta, cyan, yellow, and the like) dispersed in a wax-based material (a wax-based material) in a controlled manner to form an image. Transfer black (if possible) from the carrier to a substrate surface such as smooth paper. Thermal transfer print engines, which have a large number of independently activatable heating elements per unit length, are among the devices available for this purpose. Frequently, the carrier is positioned within the print engine such that one side of the carrier is adjacent the heating element and the opposite side of the carrier carrying the wax-based material is adjacent the substrate surface on which printing is to be performed.

To form an image, the print engine and substrate are moved relative to each other. If the printhead is to be colored at a location on the arrayed substrate surface, a suitable heating element is activated to locally heat the carrier to a temperature above the melting point of the colorant. This heating softens the amount of wax-based ink in the colorant and bonds it to the desired location on the substrate. This separates the ink from the carrier, the unheated colorant and the poorly heated colorant. To subsequently form a color image, three colors (cyan, magenta and yellow) or four colors (cyan, magenta, yellow and black) are passed sequentially with different carriers on the same substrate. Each carrier corresponds to each primary color.

Dye diffusion printing transfers dye colorants from a carrier, such as a polymer, to a special substrate surface, such as a polyester sheet, in a controlled manner to form an image. In this form of imaging using similar thermal induced subtractive printing techniques, a thermal transfer print engine and three different color dye / carrier configurations may be used. However, the operating principle of dye diffusion is different from that of thermal wax transfer printing. In dye diffusion applications, the amount of dye deposited at a single location can be varied, thus achieving fine color gradation. Dye diffusion techniques can produce near photographic quality images.

When the printheads of a thermal transfer print engine are arranged to color a position on the substrate surface, a suitable heating element is activated, up to a temperature sufficient to move an appropriate amount of dye. Heat the dye / carrier configuration. The dye is then separated from the carrier near the specially constructed substrate. In this method, due to the molecular dispersion of the dye in the substrate at the desired location, the appropriate amount of dye contacts and penetrates the substrate.

Many types of paper, especially the bond type papers common in the United States, have a rough surface, a flat top, and a hollow. Conventional thermal transfer printing techniques cannot be used efficiently with such paper. This is because the hollowness within the substrate surface structure of the paper causes adhesion problems and destroys ink or dye dots.

Also, most papers are chemically incompatible with diffusing dyes in such a way that the dye substrate in solid-solid form melts. As a result, dye diffusion techniques cannot be used to form bright colored images on such substrates. Rough surfaced "flat paper" is less expensive than special substrate materials and uses thermal transfer technology to produce high quality images, so there is no way to color print on a flat paper substrate. desirable.

One way to increase the effective substrate area in thermal transfer printing is to select the inks and dyes used to form the image. For example, Journal of Imaging Technology, 1991.
In the June / July issue, Vol. 17, No. 3, pp. 119-122, Abe and Kitamura's article "Relationship between dynamic characteristics of hot-melt ink and print quality in thermal transfer printing" was applied to monochromatic printing applications. No. 6,096,046 discloses that a highly extensible ink is used to reduce the number of voids and deterioration of an image.

Another way to increase the number of substrates available for use in monochrome printing applications is to use a carrier with multiple layers of ink to be deposited. Theoretically, as disclosed in U.S. Pat. No. 4,623,580 to Kozuka et al., A first ink layer deposited on the substrate surface improves the coating of a simultaneously coated second layer.

However, such monochromatic techniques do not follow the multi-pass principle used in subtractive printing. In multi-pass color prints, multiple coatings of colorant reduce the image resolution and adhesion as a result of the cumulative coating layer thickness.

Recently, it has been proposed to coat the substrate surface with a precoat which is smoother than the conventional substrate surface and which is chemically compatible with the intended colorant. US Patent No. 452717 by Takanashi et al.
No. 1, U.S. Pat. No. 4,670,307 to Onishi et al., And U.S. Pat. No. 4,704,615 to Tanaka disclose examples of thermal transfer printing systems that use a melt-bonded material to coat a substrate as a precoat prior to printing.

In the US patent of Takanashi et al., The entire substrate is coated and printed with a layer of binding material thereon. This method prepares the substrate for colorant coating during printing, but consumes large amounts of the binder used during the precoat process. Moreover, this results in
The surface of the substrate is noticeably smooth. This is unpleasant for those who like the look and feel of flat paper.

In the Tanaka US patent, a precoat is applied to the substrate at the same pixel location as the colorant coating is applied pixel by pixel. During the coating period of the precoat material,
Due to the long pulse width supplied to the print head elements,
This pre-coating is applied to a region at each pixel location that is slightly wider than the colorant. In this Tanaka system, the unprinted substrate portion retains the look and feel of flat paper, but there are still problems. In particular, in some cases it has been found difficult to effectively precoat the substrate at discrete 1 pixel intervals. Depending on the desired image, in areas where it is necessary to apply the colorant very thinly to the substrate,
Such problems are the most common. In this area,
As a result of the combined effect of heat loss from a single activated heating element on the print head and the transition period required to bring this heating element to its operating temperature, sometimes the precoat material on the substrate Does not provide sufficient coverage.

The precoat material according to the Tanaka US patent is designed to fill gaps or valleys on the rough substrate surface, rather than bridges across the gaps on the rough substrate surface. This is the typical precoat technique commonly used today. Japanese Patent Publication No. 62-77987 discloses coating a rough substrate with a synthetic layer of this adhesive layer and an ink layer so that the adhesive layer becomes a bridge in a gap or valley of the substrate. However, the coating of bridge type precoats or surface preparation layers supplied separately from the colorant is not currently known to those skilled in the art.

[0016]

SUMMARY OF THE INVENTION An improved system and method for making prints, which overcomes the above-mentioned drawbacks, has long been desired, but has not been realized.

Accordingly, it is an object of the present invention to provide a thermal transfer printing method and apparatus which achieves a good image adhered to a rough substrate such as bond type paper.

It is another object of the present invention to provide a thermal transfer printing method and apparatus for performing thermal transfer printing on a rough substrate and maintaining the rough appearance and feel of the substrate in areas where no image is printed.

Still another object of the present invention is a thermal transfer printing method for printing on a rough substrate of a type using a precoat for enhancing an image without degrading the image quality due to a gap in the surface of the precoat provided with a colorant. And the provision of equipment.

Another object of the present invention is to provide an improved print that matches objects.

[0021]

To achieve the above and many other objectives of the present invention, a method of thermal transfer printing on a substrate of the type characterized by a rough surface having ridges and valleys provides a rough This rough surface is pre-coated to enhance the image so as to form a bridge that intersects the valleys of the adjacent peaks of the surface, while the surface of the valley is subtended so that the surface receiving the colorant is more uniform than the rough surface. Eliminate the gaps. The colorant is then coated onto the surface of the pre-coated image enhancement precoat that receives the colorant.

Also in accordance with the present invention, a method of thermal transfer onto a substrate characterized by a rough surface having ridges and valleys comprises an image-enhancing precoat on the rough surface to partially fill the valleys of the rough surface. While removing some gaps in the valleys and forming a partial bridging effect between the peaks, forming a colorant receiving surface that is more uniform than the rough surface. Then, the colorant is coated on the colorant receiving surface of the image-enhanced precoat which is previously coated.

The apparatus of the present invention for thermal transfer printing on a substrate of the type characterized by a rough surface with peaks and valleys provides this rough surface to form bridges across the rough surface valleys between adjacent peaks. While applying an image-enhancing precoat on the surface, a structure that removes substantial gaps in the valley so as to form a surface that receives the colorant more uniformly than this rough surface, and the colorant of the pre-coated image-enhancing precoat The receiving surface is coated with the colorant of the first color.

In the method of thermal transfer printing on the substrate according to the present invention, the position where the colorant is arranged on the substrate is determined for each pixel. Next, each predetermined pixel on the substrate on which the colorant is arranged,
An image enhancement precoat is applied to each predetermined pixel and at least one pixel immediately adjacent. However, except for any pixel that is not immediately adjacent to one of the predetermined pixels, rather than one of the predetermined pixels, the adhesion of the precoat to the substrate is more secure. Then, a colorant is coated on the predetermined precoated pixels.

According to the present invention, an apparatus for thermal transfer printing on a substrate has a structure in which a position where a colorant is arranged on a substrate is covered pixel by pixel, and a device where a colorant is arranged on each substrate. Applying an image enhancement precoat to the predetermined pixels and at least one pixel immediately adjacent to each predetermined pixel (except for pixels which are not one of these predetermined pixels and which are not directly adjacent to one of the predetermined pixels); It is provided with a structure that further ensures the adhesion of the precoat to the substrate and a structure that coats the precoated predetermined pixels with a colorant.

Also in accordance with the present invention, a printed article that conveys information to an observer includes a substrate, an image enhancing precoat applied to the substrate in independent pixels, and at least one applied to a corresponding number of precoated pixels. Individual colorant pixels. It should be noted that at least one precoat pixel is placed immediately adjacent to each precoated pixel to which the colorant pixel is applied, and pixels that are not immediately adjacent to the colorant applied precoat pixel are not precoated. Thus, the pre-coated pixels are placed on the substrate.

The method of thermal transfer printing on a substrate according to the present invention is applied to the surface of the image enhancing precoat. The colorant receiving surface on the upper side of the precoat has one or more gaps. Then, the colorant receiving surface is coated with the colorant. The colorant is compounded and coated such that the coated colorant bridges across the interstices in the colorant receiving surface.

Further, according to the present invention, the apparatus for performing thermal transfer printing on the substrate has a structure for applying an image enhancing precoat to the surface of the substrate. The precoat has a colorant receiving surface with one or more gaps. The thermal transfer printing apparatus also has a configuration in which the colorant receiving surface is coated with the colorant. The colorant is compounded and coated such that the coated colorant bridges across the interstices in the colorant receiving surface.

Furthermore, the printed matter according to the present invention comprises a substrate, an image enhancing precoat adhered to the substrate, and a colorant adhered to the colorant receiving surface. The precoat has at least one gap. The colorant is also blended such that the coated colorant bridges across the gaps in the colorant receiving surface,
To be covered.

According to the present invention, a method of thermal transfer printing on a substrate is such that a colorant and an image-enhancing print to be laid on the substrate are determined pixel by pixel, and an image-enhancing precoat to be laid on the substrate is determined. In pixels to determine where to place the additional exposed precoat in contact with. Then, image enhancement precoat is applied to each predetermined pixel on the substrate on which the colorant is arranged and at least one pixel adjacent to each region where the pixel of the colorant is arranged. This further ensures the adhesion of the precoat to the substrate. In addition, the colorant is coated on the underlying precoat rather than the exposed precoat.

According to the present invention, a printed matter that conveys information to an observer includes a substrate, an image enhancing precoat adhered to the substrate, and a colorant adhered to the colorant receiving surface. The precoat has a colorant receiving surface having at least one gap. Further, the colorant is blended so as to have a viscosity lower than that of the precoat.

Further, according to the present invention, a printed matter that conveys information to an observer, a substrate, and an image-enhancing precoat, which is adhered to the substrate and includes a colorant receiving surface having at least one gap, A colorant adhered to the colorant receiving surface. The colorant is blended so as to have a melting temperature lower than that of the precoat.

The method of the present invention also employs a dye diffusion printing technique which selectively coats a desired amount of one or more dyes onto a substrate surface to reduce high or severe image defects. A high quality color image is formed on a rough substrate. Also, in the method of the present invention, a dye diffusion print engine is used to apply an image-enhancing precoat to the substrate surface prior to dye coating. Here, the image-enhancing precoat is compatible with the substrate surface enough to realize a more uniform printing surface in combination with the substrate surface, and is compatible with the dye enough to allow dye diffusion. There is also.

Furthermore, according to the transfer mechanism of the present invention, a dye-diffusion printing technique is used to selectively coat an image-enhancing precoat on the substrate surface prior to dye-diffusion, onto a rough surface substrate. Produces high quality color images with reduced many or severe image defects. This transfer mechanism, in combination with the substrate surface, provides an evenly printed surface and is compatible with this substrate surface enough to provide support for the image-enhancing portion with an image-enhancing precoat and dye diffusion. And at least one tinting portion having a dye or mixture of dyes compatible with the image-enhancing precoat so that its support is possible.

The printing apparatus of the present invention uses a dye diffusion printing technique that selectively coats an image-enhancing precoat on the substrate surface prior to dye diffusion to produce a large number of prints on a rough surface substrate. Or it produces a high quality color image with less severe image defects. The printing apparatus includes a print head capable of dye diffusion printing, a controller for directing the operation of the print head covering the image enhancing precoat and at least one dye pointing surface,
An image enhancement precoat and an input mechanism that communicates the desired dye coating location to the controller. This printing device is used with a transfer mechanism. This transfer mechanism is an image-enhancing precoat that is compatible with the substrate surface enough to provide a more uniform print surface in combination with the substrate surface and support it,
An image enhancing precoat and at least one tinting portion having a dye or mixture of dyes compatible with the dye diffusion and support thereof.

The above and various other advantages and novel features of the present invention are pointed out in the appended claims. However, for a better understanding of the present invention, preferred embodiments are described with reference to the accompanying drawings.

[0037]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the accompanying drawings, the same reference numerals indicate the same components throughout all the drawings. FIG. 2 illustrates a printing device constructed in accordance with the preferred embodiment of the present invention. A printing apparatus 10 for thermal transfer printing on a substrate 12, which may have a roughened surface 14, has a print head element 1
6, the print head element 16 responds to commands from the printer controller 18. The print head 16 according to the preferred embodiment of the present invention includes a heating element 2
Each of these heating elements comprises a linear array of zeros.
In response to a command from printer controller 18, it is heated by electrical resistance. A support roller 22 or a surface equivalent thereto is provided to support the substrate 12 in parallel and open relationship with the heating element 20. The printer controller 18 is configured to control the placement of the image on the substrate 12, as described in more detail below, by selectively controlling the heating element 20 on (contacting) the print head 16.

In general, specially designed commercial software such as Adobe PostScript ™ is used to control the image formation in printer controller 18.

The printer mechanism in the apparatus 10 is a color point PS CH-5504-PR10 (Seiko Instruments of the United States), a colormate PS model 40.
(NEC Technologies), Color Script 100 Model 10 (QMS), Phasor IIPXi (Tektronix), VY-5000 and VY150 (Hitachi), S3
40 (Mitsubishi), XL7700 and SV6500 (Kodak), 4CAST (DuPont), A4JX-560 (Sharp Electronics), UP-5000 (Sony), CIP1024P (Copal), CP-2 (Nikon) and other commercially available printers It may be one of However, the preferred device for use with device 10 is the Sharp Electronics A4JX-560 printer.

Substrate 12 such as bond type paper
In order to solve the problem of printing on the rough surface 14 of the substrate, the present invention provides the rough surface 14 rather than the surface 14 of the substrate 12 so as to obtain a surface texture and chemistry compatible with the colorant used. Apply an image enhancement precoat to.

A coating such as image enhancement precoat 30 is shown in FIG.
Shown in. As can be seen in FIG. 1, a precoat application ribbon 24 is placed between the heating element 20 on the print head 16 and the surface 14 of the substrate 12. The precoat application ribbon 24
It has a thermal resistance backing 26 and a precoat forming layer 28. The precoat forming layer 28 is adhered to the backing 26 at the side thereof. In addition, backing 2
6 is arranged adjacent to the surface 14 of the substrate 12. Upon heating the heating element 20 to a predetermined temperature by the printer controller 18, the area of the precoat forming layer 28 that is substantially equal to the surface area of the end surface of the heating element 20 is soft or molten, and the precoat application ribbon It begins to adhere to the rough surface 14 of the substrate 12 with a stronger force than it adheres to the backing 26 of 24.
In this regard, the area of the precoat forming layer 28 is separated from the application ribbon 24 and
Start sticking on the second surface 14. This area portion reaches the pixel of the precoat material 30. FIG. 1 shows the application of three adjacent pixels 32, 34, 36 of precoat material 30. Printer controller 18
Selectively provides pre-coated pixels 32, 34, 36 at predetermined locations on the substrate 12 in response to a desired image to be printed on the substrate 12. This processing will be described later in detail. Optionally, one or more treatments can be performed on each pixel to completely pre-coat.

Preferably, a material exhibiting thermal conductivity and thermal resistance is used as the backing layer 26. Examples of these substances are cellophane, polyimide film, polyester film, polyethylene film, polystyrene
Film, polypropylene film, condenser paper,
There are polymer films and papers such as glassine paper, synthetic paper and laminated paper. A preferred carrier has a thickness of about 3 microns to about 25 microns and a density of about 0.8 [gram] / [cubic centimeter] to about 1.5 [gram] / [cubic centimeter].

The backing layer 26 of the precoated application ribbon 24 is preferably formed of a layer of polyethylene terephthalic acid having a thickness of about 4-5 microns.

Precoat forming layer 28, or precoat pixels 32, 34, 36, is preferably a wax-based composition. Examples of compositions containing this wax as a main component include vegetable waxes such as carnuba wax, Japanese wax, auricree wax, and esparto wax; and animals such as beeswax, insect wax, shellac wax, and whale wax. Wax, petroleum wax such as paraffin wax, polycrystalline wax, ester wax, and oxidized wax; mineral wax such as montan wax, azocerite, and ceresin; palmitic acid, stearic acid, margaric acid, behenic acid, etc. High fatty acids; high alcohols such as palmityl alcohol, stearyl alcohol, eicosane; high fatty acid esters such as cetyl palmitate, mycilyl palmitate, cetyl stearate, myricyl stearate; acetamide, propionamide, marmityl acid Bromide, stearic acid amide, oleic acid amide,
Amides such as amides and waxes; polyamides; primary and secondary fatty acid amides; ester gums, rosin maleic acid resins; rosin derivatives such as rosin phenolic resins and hydrogenated rosins; rosin esters; phenols High molecular compounds such as resins, terpene resins, synchropentadiene resins, and aromatic resins having a melting point of about 40 to 120 degrees Celsius; high amines such as steariamine, behenialamine, palmitinamine; polyethylene glycol 40
00, polyethylene oxide such as polyethylene glycol 6000. These materials may be used individually or in combination to form the basis for the thermal wax transfer inks useful in the practice of the present invention.

Precoat forming layer 28 is preferably between 7 and 15 microns thick and is formed of a mixture of carnauba wax, paraffin wax, polycrystalline wax and ethylene vinyl acetate (EVA). The relative ratio of these components in the precoat forming layer 28 is shown in FIG.
And 4 examples will be described later in detail.

In FIG. 3, the rough surface 14 of the sub 12 is
It can be seen that it can be regarded as a series of alternating peaks 38 and valleys 40. According to the embodiment of FIG. 3, each precoat pixel 42 forms a complete bridge across the valleys 40 of the roughened surface 14 between adjacent peaks 38, removing substantial space in the valleys 40 between the peaks. As described above, the precoat substance 30 is blended. Therefore, it is possible to form a more uniform colorant receiving surface than the rough surface 14.

To achieve the full bridging effect shown in FIG. 3, the precoat material 30 is preferably about 0-3.
5% carnauba wax, 20-40% paraffin wax, 20-40% polycrystalline wax and 15-25
Formulated from% EVA.

More preferably, the complete bridge type precoat material 30 comprises about 30% carnauba wax, 20%.
Of paraffin wax, 30% polycrystalline wax and 20% EVA.

As can be seen in FIG. 3, the first colorant layer 44 may be provided directly on the upper colorant receiving surface of the first precoat pixel 42. A second colorant layer 46 is provided over the second colorant layer 44 to apply the desired color onto the area of the substrate 12 covered by the first precoat pixel 42. Instead, as shown with reference to the second precoat pixel 42, the third colorant layer 48 of the final color of interest is added to the colorant receiving surface of the second precoat pixel 42 without further application of the colorant. It may be directly coated on. A wide range of colors can be represented by providing the desired combination of the three primary colors (cyan, magenta and yellow). Alternatively, color mixing according to various known dither techniques can be used to form an overall color image on the colorant receiving surface of each precoat pixel 42.

Referring to FIG. 4, a partially complete form of precoated pixel 5 constructed in accordance with a second embodiment of the present invention.
0 is applied to the rough surface 14 of the sub 12. Partially valley 4
Each pre-coated pixel 50 is applied to the rough surface 40 to fill 0 and some space in the valley 40 is removed, creating a partial bridge effect between the peaks. The embodiment of FIG. 4, configured as the preferred embodiment, is more effective than the bridge-type precoat shown in FIG.
48 is glued. Based on that compound, it adheres to the rough surface 14 of the sub 12 with slightly less force than the precoat pixel 42 of the embodiment of FIG. This is apparently because the precoat of the example of FIG. 3 contains a thicker EVA than the precoat shown in FIG.

Preferably, the precoated pixel 50 of the embodiment of FIG. 4 has 20-60% carnauba wax, 20-20.
It contains 60% paraffin wax, 0-30% polycrystalline wax, and 5-20% ethylene vinyl acetate (EVA). Most preferred compound is about 4
It is composed of 0% carnauba wax, 40% paraffin wax, 10% polycrystalline wax, 10% ethylene vinyl acetate (EVA).

FIG. 5 illustrates the coating of colorant pixel 52 on an underlying precoat pixel 32 of the type applied to the precoat process shown in FIG. The precoat pixel 32 may be of the embodiment of FIG. 3 or FIG. The same print head 16 and printer controller 18 used to apply the precoat material are preferably used to provide colorant pixels 54. In fact, the preferred embodiment of the present invention includes a single precoat application ribbon 24.
And a continuous web of ribbons containing four repeat lengths of three colorant application ribbons 52 of three primary colors, or one precoated application ribbon 24.
And a continuous web of ribbons containing 5 repeat lengths of 4 colorant application ribbons including 3 primary colors plus black. By removing the continuous web of ribbon with respect to the print head 16, the precoat and subsequent colorant layers are removed with minimal mechanical manipulation on the substrate 1.
2 coated.

Alternatively, a printer containing two print heads, one covering the pre-coated pixels and the other covering the ink or dye, can be used in the practice of the invention. If the diffusion temperature of the colorant is different from the diffusion temperature of the precoat, or if high print speed is desired, then
Such dual print heads are most often used.

Referring again to the illustrated embodiment. The colorant application ribbon 52 is located between the linear array of heating elements 20 on the printhead 16 and the target precoat pixels 34 on the substrate 12. As can be seen in FIG. 5, the colorant application ribbon 52 includes a backing layer 56 and a colorant forming layer 58.

As described above with respect to backing layer 26, a material exhibiting thermal resistance and thermal conductivity is preferably used as backing layer 56. Examples of this material are polymeric films and papers such as cellophane, polyamide film, polyester film, polyethylene film, polystyrene film, polypropylene film, condenser paper, glassine paper, synthetic paper, laminated paper and the like. The preferred carrier has a thickness of about 3 microns to about 25 microns and a density of about 0.8 [gram] /
From [cubic centimeter] to about 1.5 [gram] / [cubic centimeter].

Various thermal wax transfer ribbons are known and are commercially available. For example, product numbers CH721U and CH730U (Seiko Instruments), 50
-080 and 50-081 (NEC Technologies),
805T13-10C3H and 805T-10C4H
(QMS), 016-0906-01 and 016-09.
06-00 (Tektronix) and the like are known. Wax transfer inks useful in the examples of the present invention include at least one wax-based colorant. Various colorants commonly used in thermal wax transfer printing include
The present invention is effective. For example, the colorant is as follows.

The yellow colorant is C.I. I. Pigment Yellow 10, 12, 16, 31, 36, 37 and C.I. I. There are dyes such as Solvent Yellow 34 and dyes described later.

The magenta colorant is C.I. I. Pigment Red 5, 49, 57: 1, 60, 81 and 83; and C.I. I. There are dyes such as Solvent Red 49 and dyes described later.

Cyan colorants include C.I. I. Pigment Blue 2, 15 and 17; and C.I. I. There are dyes such as Solvent Blue 4 and dyes described later.

The black colorant used in the present invention is C.I. I. Pigment black 6, 7, and 18, and C.I. I. Solvent Black 7 etc. For the purposes of this description, black is considered one color.

Similarly, various wax binders and other wax-based components commonly used in thermal wax transfer printing can be used in accordance with the present invention. Examples of wax-based ingredients include Carnuva wax,
Japanese wax, aurikuri wax, esparto
Vegetable wax such as wax; animal wax such as beeswax, insect wax, shellac wax, whale wax; petroleum wax such as paraffin wax, microcrystalline wax, ester wax, and oxidation wax; montan wax, Mineral waxes such as Azocerite and Ceresin; Palmitic acid, Stearic acid, Margaric acid,
High fatty acids such as behenic acid; High alcohols such as palmityl alcohol, stearyl alcohol, eicosane; High fatty acid esters such as cetyl palmitate, mycilyl palmitate, cetyl stearate, myricyl stearate; acetamide, propion Amides such as acid amides, malmitylic acid amides, stearic acid amides, oleic acid amides, amides and waxes; polyamides;
Primary and secondary fatty acid amides; ester gum, rosin maleic acid resin; rosin derivatives such as rosin phenolic resin and hydrogenated rosin; rosin ester; phenolic resin, terpene resin, synchropentadiene resin,
There are polymer compounds having a melting point of about 40 to 120 degrees Celsius such as aromatic resins; high amines such as steariamine, behenialamine and palmitinamine; and polyethylene oxide such as polyethylene glycol 4000 and polyethylene glycol 6000. These materials may be used individually or in combination to form the basis for the thermal wax transfer inks useful in the practice of the present invention.

Thermal Wax Transfer Referenced wax bases optionally include ingredients that promote thermally induced ink conductivity, such as softening agents, bulking pigments and the like. If necessary, a softening agent is used to ensure that the thermal wax transfer ink melts at the approximate temperature at which the thermal transfer printhead heating element operates. Suitable softening agents include mineral oil resins, polyvinyl acetate, polystyrene, styrene-butadiene copolymers, cellulose esters, cellulose ethers, acrylic resins, lubricating oils such as mineral oils, and print head heating. It contains a substance that causes heat-induced melting at the element temperature. EVA may be used. The softening agent is preferably present in a concentration of about 3% to 25%, based on the total dry weight of the thermal wax transfer ink.

Examples of suitable (ie, transparent) extender pigments for improving the transfer of molten ink are magnesium carbonate, calcium carbonate, kaolin clay, sericite, precipitated silica. Less than about 10%, preferably about 2%, based on the total dry weight of the thermal wax transfer ink.
The extender pigment is used at a concentration of 10% to about 10%.

A preferred thermal wax transfer ink is about 1% to about 20% colorant, about 20% to about 80% wax binder, about 3% based on the total dry weight of the thermal wax transfer ink. To about 25% softening agent. The hot wax transfer ink is coated on a carrier, preferably the construction described below. Hot melt coating,
A treatment such as a soluble coating is used for this purpose. The thickness of the coated thermal wax transfer ink layer is generally less than about 20 microns, from about 1 micron to about 1 micron.
0 micron is preferred.

Preferably, the precoat pixel 32,
The wax-based colorant forming layer 58 of the application ribbon 52 is blended so as to have a melting point lower than the melting points of 34 and 36. This is because during the coating of the colorant, the melting-related structure is
4, 36 are prevented. Comparing the optimal compound of the precoat material with the compound of the colorant material, it can be seen that the precoat material accounts for a high percentage of carnauba wax. Here, carnauba wax has a higher melting point than paraffin wax or polycrystalline wax. As a result, the melting point of the precoat component becomes higher than the melting point of the colorant component.

Further, the thickness of the precoat forming layer 28 is
It is preferably thinner than the colorant forming layer 58. This increases the strength of the coated precoat pixels 32, 34, 36 against the lumps of colorant in the coating, thus avoiding strong precoat damage that affects the overall image quality.

The viscosity of the precoat material is preferably higher than the colorant material. The optimum precoat compound viscosity is about 250-300 centipoise at 100 degrees Celsius. At the same temperature, the optimum colorant viscosity is about 100 centipoise. The highly viscous precoat makes the precoat pixels 32, 34, 36 more stable so that the colorant coating can be applied without deformation. The low viscosity colorant facilitates setting in the precoat.

The colorant forming layer 58 is preferably 1 to 20.
% Ink or migration, 3-10% softening agent 70-90% wax binder. Optimally, the colorant-forming layer comprises about 60% paraffin wax, 20% carnauba wax, 5% EVA for tackifying as a softening agent, 10% polycrystalline wax and 5% colorant. Including. The colorant layer 58 is preferably about 3 microns thick.

In operation, printer controller 18 commands heating element 20 to heat the area of colorant application ribbon 52 to a predetermined temperature. This area is
It corresponds to the end face area of the heating element 20. At this predetermined temperature, the colorant forming layer 58 melts and adheres itself to the target precoat pixel 34. Preferably,
The forming layer 58 does not actually melt.

The printed matter formed by the above-described process and which conveys information to the observer includes the substrate 12 and the image-enhancing precoat applied to the substrate 12 with the individual pixels 32, 34, 36, and a corresponding number. Precoat
At least one colorant pixel 54 provided to the pixel 34. Position at least one of the precoat pixels 32, 34, 36 immediately adjacent each precoated pixel having the colorant pixel 54 to precoat pixels that are not immediately adjacent to the precoated pixel to which the colorant is applied. Do not apply precoat pixels 32, 34, 36 to substrate 1
Arrange on 2. In accordance with the preferred embodiment of the present invention, each precoat pixel having colorant pixels 54 is surrounded by adjacent precoat pixels 32, 36, thus forming a precoat boundary around each colorant pixel.

Another apparatus and method for applying colorant to the target precoat pixels 34 is shown in FIG. This Figure 6
As can be seen, a dye diffusion colorant application ribbon 60 is placed between the linear array of heating elements 20 on the printhead 16 and the target precoat pixel 34. The colorant application ribbon 60
It includes a backing device 62 and a dye diffusion carrier layer 64. When heated, the dye material penetrates the carrier layer 64 and diffuses into the adjacent target precoat pixel 34. By varying the temperature and time that the colorant application ribbon 60 is exposed to the heating element 20, the target precoat pixel 34 can be changed.
The amount of dye diffused in can be controlled more accurately than is possible with the wax transfer technique used in the example of FIG. In the preferred embodiment of operation, the dye diffusion printing process is as follows. Place a pair of rough papers 12 in a dye diffusion printer having a continuous carrier ribbon. An image-enhancing substance, a yellow dye, a magenta dye, and a cyan dye are arranged thereon in a sequential repeating unit in the longitudinal direction. Partial heating by heating of the elements of print head 16 provides complete or selective coating of the substrate on the image enhancing precoated ribbon. Heating the elements of the print head heats the continuous yellow, magenta, and cyan dye / carrier ribbon portions and partially heats them to produce an image on the substrate surface 14.

Preferably, the precoat materials used in the dye diffusion examples of the present invention can be coated on a rough substrate surface by a conventional or slightly modified dye diffusion printer. Dye diffusion and thermal wax transfer printers operate in the same manner (ie, with partial heating for coating), so wax-based or other substantially identical image enhancement precoats are Can be coated.

If the dye and precoat exhibit substantially different migration and melting temperatures, control of the print head heating element temperature is required. More specifically, different temperatures are needed to melt coat the image-enhancing precoat more than is necessary to transfer coat the dye. Dual head temperature, dual head or other suitable devices may be used in such embodiments of the invention.

For the dye diffusion embodiments of the present invention, the image enhancing precoat must be compatible with the dye with which it is used. In this state, the term "compatibility" implies the ability to physically or chemically interact with the dye to produce a bright colored image. The molecular weight II dispersion of the dye results in an image having this desired color brightness feature. Due to their inability to molecularly disperse, the dye molecules preferably adhere to each other. The paper substrates used in the practice of this invention have no room for their molecular dye dispersion. As a result, the dye is preferably miscible or forms the image-enhancing precoat and solid-in-solid solution of the dye diffusion embodiments of the present invention. Dye diffusion within an image enhancement precoat is similar to the processing that occurs between dye and polymeric film, for example.

Thus, the image-enhancing precoat in this embodiment of the invention is selected in part by dye solubility or wettability. Solid solutions in dye solids forming substances such as organic polymers, polyamide waxes, etc. are, for example, image-enhancing precoats for practical embodiments of the invention.

Further, the image enhancing precoat may include one or more additives capable of dye diffusion. For example, fine particles such as finely divided polymeric particles may be dispersed within an image enhancing precoat such as a low melt adhesive compound (eg, polyamide, wax, etc.). For example, polyester particles having a diameter of about 10 microns or less may be used in the practice of the present invention. Upon application of the appropriate amount of heat, the dye migrates from the carrier and molecularly diffuses into the precoat containing such particulate material, resulting in a bright colored image on the substrate. This in itself is unacceptable for such dye dispersions.

In the practice of the present invention, the thickness of the precoat layer containing fine particles disposed on the substrate is determined by factors such as the level of addition of fine particles. Generally, as the concentration of particulate material in the precoat material increases, the thickness of the layer needed to produce a solid-in-solid solution decreases. The amount of dye coated anywhere will affect the physical lower limit of the precoat (ie, the layer must be thick enough for particulate addition and dye diffusion). Also, the desired optical density of the predictable color dictates at least some of the precoat thickness parameters. Thicker layers are preferred for this purpose because the prediction of optical density is a function of the uniformity of the precoat layer, among other things. Because the chemical and physical structures of the dyes and precoat components are known or can be ascertained, conventional microparticles can provide and provide image enhancement components or precoats useful in the dye diffusion embodiments of the present invention.

Another important concept of the present invention is shown in FIG. As can be seen from this FIG. 7, the precoat material according to the invention is applied to a larger area of the substrate 12 than the area to be coated with the colorant, but not to the entire surface of the substrate 12. This causes a remarkable change in the surface texture of the substrate 12. More specifically, the preferred embodiment of the present invention provides an image enhancement precoat to each predetermined pixel on the substrate on which the colorant is to be placed, and to at least one pixel immediately adjacent to each such predetermined pixel. An apparatus and method for performing the above are provided. However, pixels that are not one of the predetermined pixels, or pixels that are not directly adjacent to one of the predetermined pixels, are not image enhanced precoated. As a result, it is possible to more reliably bond the precoat to the substrate without unnecessarily wasting the precoat or changing the apparent surface texture of the substrate.

In accordance with the preferred embodiment of the present invention, an image enhancement precoat is applied to each pixel immediately adjacent to each pixel to be coated with the colorant so that a precoat is provided around each pixel to be coated with the colorant. Form the boundary of.

To accomplish this process, the printer controller 18 first determines, on a pixel-by-pixel basis, where on the substrate the colorant and underlying image enhancing precoat will be placed. In Figure 10, this step is called "shadow
Create mask ". In addition, the printer controller 18
Determines, on a pixel-by-pixel basis, where to place an additional exposed precoat adjacent to the underlying image enhancing precoat. In Figure 10, this second step is "Create Surroundings"
Show as. Next, the printer controller 18 causes each predetermined pixel of the substrate on which the colorant is to be placed, and
An image enhancement precoat is applied to at least one additional pixel adjacent each region in which the colorant pixel is to be located. The printer controller 18 then commands the coating of the colorant on the underlay precoat.

As the third step, the printer controller 18
To adjust the peripheral pattern based on the shape of the shadow mask. In FIG. 10, this step is shown as “filling the gap”. For example, the step of filling this gap in a region where the colorant is to be distributed sparsely applies a pre-coating not only to the pixel immediately adjacent to the pixel to be coated with the colorant. The precoat border area may be reduced in dense areas.

As an example of the preferred embodiment, the printer controller 1
8. First, as shown in FIG. 7, as shown in FIG. 7, the pixel (G, 8) is determined to be coated with the colorant as a part of the shape of the character “E”. When the printer controller 18 makes such a determination,
The printer controller 18 determines that each pixel adjacent to the pixel (G, 8) is a pixel (F, 7), (F, 8),
(F, 9), (G, 9), (H, 9), (H, 9),
It is determined whether (H, 7) and (G, 7) are to be precoated. When the printer controller 18 makes this determination, it instructs the device 10 to apply a precoat to the predetermined pixels. In the illustrated embodiment, the step of filling the gap does not change the shape of the precoat boundary. Subsequently, a colorant is applied to the preselected pixels (G, 8). The printer controller 18 may execute this processing for each line or each area. Alternatively, it is also possible according to the invention to apply a precoat over a large area above the immediately adjacent pixels.

The printed product shown in FIG. 7 has a substrate 12, an image enhancement precoat applied to the substrate within individual pixels 32, 34, 36 and at least one precoated pixel 34 of a corresponding number. And colorant pixels 54. Pre-coating such that at least one pre-coated pixel is placed immediately adjacent to each pre-coated pixel having a colorant pixel, and pixels that are not immediately adjacent to the colorant-provided pre-coated pixel Arrange the precoated pixels on the substrate so that they do not exist. Optimally,
Each precoat pixel 3 with colorant pixel 54
4 is surrounded by adjacent precoat pixels 32, 36, thus forming a precoat boundary around each colorant pixel. According to the embodiment of the present invention shown in FIG. 5 or 6, a coloring agent can be applied.

8 and 9, printed matter 66, 80 according to the present invention comprises a substrate 12 and an image-enhancing precoat 42 adhered to the substrate 12.
50, a precoat including a colorant receiving surface having at least one gap, and a colorant adhered to the colorant receiving surface. Colorants 78, 88 are compounded and coated so as to bridge across the gaps in the colorant receiving surface.

It can be seen in FIG. 8 that the rough surface 14 and the substrate 12 include adjacent peaks 68, 70, 72. The peaks 68, 72 are substantially higher than the peak 70 and are located between the peaks 68, 72. Due to this height difference, while being constructed and blended according to the embodiment of FIG. 3,
The precoat pixel 42 bridging the adjacent peaks 68, 70, 72 falls slightly downward and adheres to the second peak 70 between the peaks 68, 72. This creates a gap 76 between the precoat pixel 42 and the colorant pixel 78. The colorant pixels 72 are bridged so as to bridge the gap 76 without the detrimental effects of cracking or breakage.
Is compounded.

Similarly, FIG. 9 shows a print 80, the precoat material being a precoated pixel 50 formulated and coated according to the embodiment of FIG. Gaps 84, 86 between the precoat pixels 50 and the colorant pixels 88 to drop the precoat pixels 50 into the valleys of the substrate 12 to accommodate the rough surface 14.
To form. Again, bridging the gaps 84, 86 without any harmful effects such as cracks or breaks,
Contains a colorant pixel.

While many features and advantages of the present invention have been set forth above together with the detailed structure and function of the invention, various modifications, such as shape, size and arrangement, may be made without departing from the spirit of the invention. Can be changed.

[0088]

As described above, according to the present invention, thermal transfer printing can be reliably performed on a rough substrate such as bond paper, and the rough appearance and feel of the substrate in the area where the image is not printed are maintained. be able to.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration in which a precoat substance is applied onto a substrate in an apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram of a printing device according to a preferred embodiment of the present invention.

FIG. 3 is a view showing a state in which an underlay substrate is subjected to a precoat of the first type of the present invention.

FIG. 4 is a view showing a state in which a second type precoat of the present invention is applied to an underlay substrate.

FIG. 5 illustrates a composition for applying a wax transfer colorant onto a precoated substrate according to the present invention.

FIG. 6 is a diagram showing a configuration in which a colorant is applied to a precoated substrate by a dye diffusion treatment.

FIG. 7 is a diagram illustrating a novel method of applying a precoat on a substrate according to one aspect of the present invention.

FIG. 8 shows a novel colorant material according to the present invention with a pre-coated material according to the embodiment of FIG.

9 illustrates the colorant material of FIG. 8 overlying the precoat material provided by the example of FIG.

FIG. 10 illustrates a flow chart according to one aspect of the invention.

[Explanation of symbols]

 12 Substrate 14 Rough Surface 16 Print Head 18 Print Controller 20 Heating Element 22 Support Roller 24 Precoat Application Ribbon 26 Thermal Resistance Backing 28 Precoat Forming Layer 30 Precoat Material 32, 34, 36 Pixels

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI Technical indication 8305-2H B41M 5/26 Z (72) Inventor Thomas J. Brand Oregon, USA 97013 Canby North・ East Twelve's Avenue 400

Claims (2)

[Claims] 1. A method of thermal transfer printing on a substrate having a rough surface having ridges and valleys, wherein said rough surface is image enhanced precoated to cross said valleys between adjacent ridges of said rough surface. Form a complete bridge to substantially eliminate the voids in the valleys between the ridges and to form a more uniform colorant receiving surface than the rough surface. A thermal transfer printing method, characterized in that a surface is coated with a colorant. 2. An apparatus for performing thermal transfer printing on a substrate having a rough surface having ridges and valleys, wherein the rough surface is subjected to image enhancement precoating to cross the valley between adjacent ridges of the rough surface. To form a complete bridge to substantially eliminate the voids in the valleys between the ridges and to form a colorant-receiving surface that is more uniform than the rough surface, and coloring the already-enhanced image-enhancing precoat. A thermal transfer printing apparatus comprising means for coating a colorant on the agent receiving surface.