JPS62181187A - Thermal transfer medium and thermal transfer recording method using the same - Google Patents

Abstract

PURPOSE:To make it possible to prevent a thermally transferable ink from being adhered to a patternwise heat-supplying member such as a thermal head which makes direct contact with a thermal transfer medium and to maintain clearness of transfer-recorded images during repeated recording, by forming the thermal transfer medium by using a thermally transferable ink in which heat-resistant fine particles are dispersed. CONSTITUTION:An ink roll 1 as a thermal transfer medium is cylindrical in shape, and at lest the outer peripheral surface thereof is constituted of a thermally transferable ink 3 in which heat-resistant fine particles 2 are dispersed. If required, a core member 11 formed of a metal, a resin or the like is provided in the inside of the ink roll 1. Under a relatively low pressure exerted when heat is applied directly to the medium by a thermal head or the like, the fine particles 2 dispersed in the medium restrict the contact of the ink 3 with the thermal head or the like to within an appropriate range, so that the ink 3 is prevented from being adhered to the thermal head or the like.

Description

[Detailed Description of the Invention] 1. The present invention relates to a thermal transfer medium capable of providing a clear transferred recorded image while effectively utilizing patterned energy according to a desired image signal, and the thermal transfer medium. The present invention relates to a thermal transfer recording method using.

LjL! The thermal transfer recording method, which is widely used as one of the methods for recording on L-sized plain paper, generally involves applying thermal transfer ink, which is made by dispersing a coloring agent in a heat-melting binder, onto a sheet-like support. Recording is performed by using a heat-sensitive transfer material formed by coating, and by supplying heat from the support side of the heat-sensitive transfer material with an external heat-generating member such as a thermal head, and transferring selectively melted heat-transferable ink to a recording medium. A transfer recording image is formed on the medium according to the shape of heat supply.

However, in the conventional thermal transfer recording method, patterned heat is applied to the thermal transfer material from the support side, so the thermal transfer ink layer is heated through the support, and the thermal energy is There was a loss.

11 Ritan 3 The main object of the present invention is to provide a thermal transfer medium that can effectively utilize patterned thermal energy while eliminating the drawbacks of the conventional thermal transfer recording methods described above and maintaining various thermal transfer performances. Another object of the present invention is to provide a thermal transfer recording method using the same.

11. The inventors previously used a thermal transfer medium in which thermal transfer ink itself was formed in the form of a roll, and directly applied heat or voltage to the outer peripheral surface of the medium to impart pattern-like tackiness. rear,
By press-transferring the thermal transfer ink onto the recording medium while this adhesive pattern is maintained, it eliminates the loss of thermal energy caused by the conventional patterned heat supply via the support, and at the same time it is compact. We have proposed a thermal transfer recording method using a thermal transfer device that eliminates the need for the conventionally used expensive thermal transfer material and reduces the cost of thermal transfer recording (Japanese Patent Application No. 168,788/1988).

As a result of further research in order to improve this thermal transfer recording method, the present inventors have found that forming the thermal transfer medium using a thermal transfer ink in which heat-resistant fine particles are dispersed allows direct contact with the thermal transfer medium. It is extremely effective in achieving the above objectives by significantly suppressing the adhesion of thermal transfer ink to a patterned heat supply member such as a thermal head, and at the same time making it possible to maintain a clear transferred recorded image during repeated recording. I found out.

The thermal transfer medium of the present invention is based on this knowledge, and more specifically, the thermal transfer medium of the present invention has a surface layer made of a solid thermal transfer ink in which heat-resistant fine particles are dispersed, and is smoothed.

Further, the thermal transfer recording method of the present invention using the above-mentioned thermal transfer medium has a surface layer made of a solid thermal transfer ink in which heat-resistant fine particles are dispersed, on the ink surface of the thermal transfer medium.
A step of selectively melting or softening the thermal transfer ink by applying heat or voltage in a pattern, bringing the ink surface of the thermal transfer medium into contact with a recording medium, and bringing the thermal transfer ink into a melted or softened state according to the pattern. The method consists of a step of press-transferring the image onto a recording medium.

The heat-resistant fine particles dispersed in the thermal transfer medium of the present invention prevent the thermal transfer ink from coming into contact with the thermal head etc. under a relatively low pressure when heat is directly applied to the medium by the thermal head etc. This prevents the thermal transfer ink from adhering to the thermal head or the like.

Hereinafter, the present invention will be described in further detail with reference to the drawings as necessary. In the following descriptions, "%" is used to express quantitative ratio.
” and “parts” are based on weight unless otherwise specified.

FIG. 1 is a schematic side sectional view showing a basic aspect of the thermal transfer medium of the present invention.

Referring to FIG. 1, the ink roll l, which is a thermal transfer medium, is
It has a cylindrical shape, and at least its outer peripheral surface is made of heat-resistant fine particles 2.
This is a member made of thermal transfer ink 3 in which is dispersed,
Inside the ink roll.

A core material 11 made of metal, resin, etc. may be arranged as necessary.

Further, the ink roll 1 may have another rotating body shape (for example, a truncated conical shape).

The heat-resistant fine particles 2 used in the present invention have a melting point higher than the melting point of the thermal transferable ink 3 by at least 20°C or higher, preferably by 30°C or higher (including cases where the heat-resistant fine particles are substantially non-melting). It is defined as fine particles that are less likely to undergo melting and deformation when heat is applied. Here, for heat-resistant fine particles 2 and thermal transfer ink 3 that do not exhibit a fixed melting point, "softening point by ring and ball method" is used instead of "melting point".

Such heat-resistant fine particles 2 include non-alloyed fine particles,
Any organic fine particles can be used, but examples of inorganic fine particles include metals such as aluminum, copper, and iron, alumina, metal oxides such as magnesium oxide, titanium oxide, and magnesium oxide, zinc sulfide, molybdenum sulfide, etc. Fine particles made of metal oxides, salts such as magnesium carbonate, calcium carbonate, and barium sulfate, and minerals such as kaolin, clay, talc, and zeolite are used.

On the other hand, examples of organic fine particles include phenolic resin, melamine resin, urethane resin, epoxy resin, silicone resin, urea resin, diallyl phthalate resin, alkyd resin, acetal resin, acrylic resin, methacrylic resin, polyester resin, cellulose resin, Starch and its derivatives, polyvinyl chloride, polyvinylidene chloride, chlorinated polyethylene, fluororesin, polyethylene,
Polypropylene, polystyrene, polyvinyl acetal, polyamide, polyvinyl alcohol, polycarbonate, polysulfone, polyether sulfone, polyphenylene oxide, polyether ether ketone, polyamino bismaleimide, polyarylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyimide, polyamideimide , polyacrylonitrile, AS resin, ABS resin, SBR (styrene butadiene rubber), etc., and resins mainly composed of these are used. Among these, fine particles of resins with a softening point of 150°C or higher by the ring and ball method are used. is preferably used.

The average particle diameter of such heat-resistant fine particles 2 is 0°1 to 30°.
g m, more preferably 0.5 to 10 gm. If the average particle size is less than 0.1 uLm, it is insufficient to suppress ink adhesion to the thermal head, etc. On the other hand, if the average particle size exceeds 30 gm, the thermal head Application of heat in a pattern to the thermal transfer ink 3 due to the above-mentioned problems is no longer good.

Heat-resistant fine particles 2 have thermal transferability of 477,100 parts,
It is preferably dispersed in a proportion of 1-ioo parts, more preferably 2 to 70 parts. If this proportion is less than 1 part, the adhesion of ink to a thermal head etc. will be insufficiently suppressed, while if this proportion exceeds 100 parts, patterned heat application to the thermal transfer ink will not be satisfactory. In addition, this heat-resistant fine particle 2
is preferably uniformly dispersed in the thermal transfer ink 3 from the viewpoint of improving the homogeneity of the recorded image.

The thermal transfer ink 3 that constitutes the ink roll 1 together with the heat-resistant fine particles 2 is formed by dissolving or dispersing a coloring agent such as a dye or a pigment in a heat-melting binder.

As the heat-melting binder, various conventionally used natural or synthetic binders such as waxes and resins can be used alone or in combination of two or more.

As this heat-melting binder, a heat-melting binder having supercooling property (hereinafter referred to as "supercooling heat-melting binder") is used.
), the thermal transfer ink 3 maintains a melted or softened state for a certain period of time even after the heat application is finished, so when using the ink roll 1, the position of heat application to the outer circumferential surface of the ink roll l by a thermal head etc. This is preferable because it is easy to provide a wide interval between the ink transfer position and the ink transfer position to the recording medium.

Here, the supercooled thermofusible binder refers to a binder that, when once heated above the melting point and cooled from the molten state, maintains the above-mentioned molten state for a certain period of time even at a temperature below the original melting point.

For binders that do not exhibit a fixed melting point, "softening point" is used instead of "melting point" and "softening" is used instead of "melting".

Such supercooled thermofusible binders include, for example, plasticizers such as N-cyclohexyl-p-)luenesulfonamide, N-ethyl-p-toluenesulfonamide, and dicyclohexyl phthalate, which are known supercooled substances; Alternatively, benzotriazole, acetanilide, etc., or their derivatives alone or in combination of two or more,
Thermoplastic resins used in conventional thermal transfer inks such as polyamide resins, polyacrylic resins, polyvinyl acetate resins, or copolymers thereof (preferably those with a softening point of 40 to 230°C by the ring and ball method, more preferably 50°C) ~20
It can be obtained by mixing it into a conventional heat-melting binder made of various waxes, etc.). In this case 1, for example, 20 to 900 parts of the above-mentioned supercooled substance may be mixed with 100 parts of a conventional heat-fusible binder.

In addition to the above-mentioned supercooled thermofusible binder, the supercooled thermofusible binder used in the invention related to the applicant's previous application (Japanese Patent Application No. 173984/1984) is also preferably used.

Adding an oil or the like to these supercooled hot-melt binders to adjust their supercooling properties, or adding elastomers or the like to these or ordinary hot-melt binders to adjust melt viscosity, adhesive strength, etc. is also possible.

As the coloring agent that constitutes the thermal transfer ink 3 together with the supercooled thermofusible binder or the ordinary thermofusible binder, for example, dyes and pigments commonly used in printing or other recording methods such as carbon black can be used. All of these dyes and pigments are used individually or in a mixture of two or more.The content of the colorant is preferably 1 to 40% based on the thermal transfer ink 3.

To obtain the ink roll 1 used in the present invention, for example, the above-mentioned supercooled thermofusible binder or ordinary thermofusible binder, colorant, and #thermal fine particles 2 are melt-kneaded using a dispersion device such as a 7 triter. A thermally transferable ink is obtained, and the ink is molded into a desired rotating body shape using a mold or the like, using a core material if necessary.

Next, a thermal transfer recording method of the present invention using the above-described ink roll 1 will be explained.

FIG. 2 shows an embodiment of the present invention in which a thermal head is used as a source of heat for melting or softening thermal transfer ink (hereinafter, this heat supply method is referred to as "r thermal head method"), and shows a recording medium. FIG. 3 is a schematic cross-sectional view in the thickness direction.

Referring to FIG. 2, an ink roll l whose outer peripheral surface is made of thermal transferable ink 3 in which heat-resistant fine particles 2 are dispersed is placed with its core material 11 held by a spring 4a, and is positioned at an arrow A.
rotate continuously or intermittently in a direction.

On the other hand, a thermal spatula 5, which is arranged on the outer circumferential surface of the rotating ink roll l on the right side (upstream of the transfer position) and comes into contact with the outer circumferential surface by the action of a spring 4b, generates an image according to a desired image pattern. When heat is supplied to the thermal transferable ink 3 constituting the outer peripheral surface, the ink 3 melts or softens depending on the heating pattern, and at the same time becomes sticky.
Although the ink 3 has transferability to the recording medium 6, the ink 3 moves upward in the figure as the ink roll 1 rotates.

While the adhesive pattern of the thermal transferable ink 3 corresponding to the heat supply shape is maintained, the outer peripheral surface of the ink roll l is transferred to the recording medium from the right side to the left side in the figure at the transfer position. 6, but at this time, the thermal transfer ink 3, which maintains the above-mentioned patterned sticky state under pressure from the pressure roll 7 facing the ink roll 1 with the recording medium 6 in between, A transferred recorded image 8 is formed by pressure transfer onto a recording medium 6.

After the above-described transfer process, the ink roll l further rotates from the transfer position in the direction indicated by the arrow, and its uneven outer peripheral surface is smoothed by a blade 9 disposed upstream of the thermal head 5 and connected to a spring 4c. The ink scraped off by the blade 9 is collected in the ink reservoir io.

In the above recording method, a plurality of ink rolls 1 may be used for multicoloring, etc., and instead of smoothing with the blade 9, a heating roll that heats the outer peripheral surface to a certain extent and melts or softens it again is used. Smoothing may be performed using a member such as (not shown).

Thermal head 5 of the thermal transfer recording method of the present invention as described above
In the case of applying heat by , as long as the outer peripheral surface of the ink roll 1 and the heating pad 5 are in sufficient contact to apply heat in the desired pattern, the applied pressure may be 2 K g/cm' or less, and the applied pressure may be 2 K g/cm' or less, and For the pulse 10, a condition of 0.5 to 5 m5ec is suitably adopted.

Further, in the ink transfer step of the recording method, the pressure applied to the recording medium 6 between the pressure roll 7 and the ink roll 1 is preferably larger than the above-mentioned applied pressure during heat application. is linear pressure 0.5~10kg
/am, more preferably 1 to 5 Kg/cm.0 The pressure is preferably large, from the viewpoint of sufficiently adhering the thermal transfer ink to the four surfaces of the recording medium with poor surface smoothness.

The distance between the transfer position where the pressure roll 7 faces the ink roll 1 and the above-mentioned thermal head 5 is such that the thermal transfer ink 3 constituting the outer peripheral surface of the ink roll 1 is melted or softened in a desired pattern. The interval is set to a value that can be maintained.

In the following, with reference to FIG. 2, ink roll 1
Although the thermal transfer recording method of the present invention using the above has been described, just to be sure, Waka-P's explanation will be added regarding the function of the heat-resistant fine particles 2 in the ink roll 1 during heat application and ink transfer in this recording method.

Dispersing the heat-resistant fine particles 2 with reference to FIG. 3(a), which is a microscopic schematic side cross-sectional view showing the outer circumferential surface of the ink roll 1 and the shape of the heating element 5a of the heating element 5a when L heat is applied. Thermal energy is applied to the outer circumferential surface of the ink roll l made of the thermally transferable ink 3 from the heating element 5a in contact with the outer circumferential surface. In this case, since the pressure applied from the heating element 5a to the outer peripheral surface of the ink roll 1 is relatively small,
Due to the presence of the heat-resistant fine particles 2 near the outer peripheral surface, adhesion of the melted or softened thermal transfer ink 3 to the heating element 5a is effectively suppressed.

Next, at the transfer position, as shown in FIG. Since a relatively large pressure is applied from the roll 7, the heat-resistant fine particles 2 are embedded in the ink layer 3 which is still in a melted or softened state, and a state of close contact between the recording medium 6 and the thermal transfer ink 3 is obtained. As a result, as shown in FIG. 3(C), a transferred recorded image 8 faithful to the heat application pattern is formed on the outer peripheral surface of the ink roll 1 and the separated recording medium 6.

In this way, in the above-mentioned thermal transfer recording method, since the adhesion of the thermal transfer ink 3 to the heating element 5a of the thermal pad 5 is suppressed, the sharpness of the recorded image decreases due to the adhesion and adhesion of the ink. There is no decrease in the durability of the heating pad 5, and the clarity of the transfer recording t8 is maintained well even during repeated recording. In addition, the heat-resistant fine particles 2 also have the function of preventing background smudges on the recording medium 6 caused only by contact with the non-heat-applied portion of the outer circumferential surface of the ink roll l. Contribute.

In the above description of the thermal transfer recording method, an embodiment of the present invention has been described in which a thermal head method is used, that is, a thermal head is used as a heat source in the thermal impression process. shaped recording electrode (JP-A-58-220795, JP-A-58-
12790, etc.) together with the ink roll l in which the thermal transfer ink 3 (or in addition to this, the heat-resistant fine particles 2) is made conductive, the above-described recording method may be carried out in the same manner.

The ink roll 1 of the present invention is particularly preferably used in a recording method using a heat supply means that directly contacts the outer peripheral surface of the ink roll 1, such as the above-mentioned thermal head 5 or recording electrode. Even when used in a similar recording method using a supplying means, it is possible to prevent scumming of the recording medium corresponding to the non-heat-applied portion of the outer circumferential surface of the ink roll l.

The embodiment of the present invention in which the thermal transfer medium is formed into an ink roll shape has been described above, but the thermal transfer medium of the present invention has a support made of a plastic film or the like, as shown in a schematic cross-sectional view in the thickness direction in FIG. A layer of thermal transferable ink 3 in which heat-resistant fine particles 2 are dispersed (preferably a thickness of 0.5 to 15 cm) is formed on the body 12 (preferably about 2 to 15 cm thick).
A sheet-like thermal transfer medium 1a having a thickness of about 40 gm) may also be used.

When using such a sheet-shaped thermal transfer medium 1a, for example, as shown in FIG.
Thereafter, the melted or softened ink may be transferred to the recording medium 6 by pressure.

Even when the thermal transfer medium of the present invention is this sheet-like thermal transfer medium 1a, the above-mentioned ink roll-like thermal transfer medium l
It is easy to understand that the same effect as in the case of .

Color difference] As described above, the present invention provides a thermal transfer medium having a surface layer made of a thermal transferable ink in which heat-resistant fine particles are dispersed, and a thermal transfer recording method using this thermal transfer medium.

By using the thermal transfer medium of the present invention, it is possible to supply energy in a pattern directly to the surface of the thermal transferable ink, thereby effectively utilizing the energy, and at the same time, preventing the ink from adhering to the heat application means. It becomes possible to improve the durability of the heat application means and maintain the clarity of the recorded image.

In addition, according to the recording method of the present invention using the above-mentioned thermal transfer medium, recording costs are reduced in terms of energy costs etc. by supplying patterned heat directly to the thermal transfer ink (without going through a support). can be done.

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Referring to FIG. 1, a thermal transfer ink 3 having supercooling properties in which heat-resistant fine particles 2 were dispersed was prepared according to the following recipe.

Carbon black 5 parts Polyamide resin 80 parts (Sanmide #55, manufactured by Sansho Kagaku Co., Ltd.) N-ethyl p-15 parts Toluene sulfonamide silica fine particles 5 parts (average particle size 3 m, manufactured by Degussa Corporation) As shown above Thermal transfer ink (melting point 62°C) obtained by dispersing and mixing each component while heating at 110°C was
The ink roll 1 shown in FIG. 1 was formed into a cylindrical shape with a diameter of 60 mm centered around a core material 11 made of resin.

Furthermore, using the thermal transfer recording device shown in FIG.
(Applied pulse width: 1.1m5ec, applied pressure 1.0Kg
/cm") to directly apply heat to the outer peripheral surface of the ink roll L, the thermally transferable ink 3 softened in a pattern is applied with a linear pressure of 2 between the ink roll L and the pressure roll 7.
While applying a pressure of K g/cm, the image was transferred onto high-quality paper 6 as a recording medium to form a recorded image 8.

The recorded image on this high-quality paper is visually good in print quality such as print density, transferability, and sharpness.

In addition, compared to the thermal transfer recording method using a conventional thermal transfer material, the recording cost is low mainly because the support is omitted, and the thermal energy consumption is also low.

Next, the above operation was repeated while smoothing the outer peripheral surface of the ink roll 1 with the blade 9, but the sharpness of the recorded image did not deteriorate and was maintained well.

After repeating the above procedure, the heat generating element 5a portion of the heating element 5 was observed using an optical microscope, but no adhesion of the thermal transferable ink 3 to the surface of the heat generating element 5a was observed.

Example 1 was carried out in the same manner as in Example 1, except that instead of the silica particles, a thermal transfer ink in which benzoguanamine-formaldehyde condensate particles (Epostor, manufactured by Nippon Shokubai Chemical Co., Ltd., average particle size 21 Lm) were dispersed was used. ,
A clear recorded image similar to that in Example 1 was obtained. Further, the surface of the heating element 5a after use was observed under a microscope in the same manner as in Example 1, but no adhesion of thermal transferable ink was observed.

Comparison L 1 When the same procedure as in Example 1 was carried out except for using the thermal transfer ink 3 to which no silica particles were added, stains other than the recorded image were generated on the high-quality paper 6, and the clarity of the recorded image was not good. Ta. Furthermore, when the portion of the heating element 5a after use was observed under a microscope in the same manner as in Example 1, adhesion of thermal transferable ink was observed.

[Brief explanation of drawings]

FIG. 1 is a schematic side sectional view showing an embodiment of the thermal transfer medium of the present invention, and FIGS. 2 and 4 are schematic diagrams in the thickness direction of the recording medium showing embodiments of the thermal transfer recording method of the present invention, respectively. 2 shows an embodiment using the thermal transfer medium of FIG. 1, FIG. 4 shows an embodiment using a thermal transfer medium formed entirely in a sheet shape, and FIGS. 3(a) to 3(c)
) are schematic side sectional views showing microscopic aspects of the surface of the thermal transfer medium of the present invention during heat application, during ink transfer, and after ink transfer, respectively. l... Ink roll, 11... Core material, 2... Heat resistant fine particles. 3... Thermal transfer ink, 4a, 4b, 4c... Spring, 5... Thermal head, 6... Recording medium. 7...Pressure roll. 8... Transfer recorded image, 9... Blade, 10... Ink reservoir. 12...Support. υJ: Figure 2

Claims (1)

[Scope of Claims] 1. A thermal transfer medium characterized by having a surface layer consisting of a solid thermal transfer ink in which heat-resistant fine particles are dispersed. 2. The thermal transfer medium according to claim 1, wherein the thermal transfer ink is formed into the shape of a rotating body. 3. Applying patterned heat or voltage to the ink surface of a thermal transfer medium having a surface layer made of solid thermal transfer ink in which heat-resistant fine particles are dispersed to selectively melt or soften the thermal transfer ink. A thermal transfer recording method comprising the steps of: bringing the ink surface of the thermal transfer medium into contact with a recording medium, and press-transferring the thermal transfer ink in a melted or softened state according to the pattern onto the recording medium. 4. A claim in which an ink roll formed by molding the thermal transfer ink into the shape of a rotating body is used as the thermal transfer medium, and the outer circumferential surface of the ink roll is smoothed after the step of press-transferring the thermal transfer ink to the recording medium. The thermal transfer recording method according to item 3.