JP2988484B2 - Thermal transfer sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a heat transfer sheet that is superimposed on a heat transfer sheet, for example, by performing dot heating according to image information from the back side of the heat transfer sheet. The present invention relates to a thermal transfer sheet for forming an image on a surface.

[Conventional technology]

2. Description of the Related Art Conventionally, there has been known a thermal transfer sheet provided with a detection mark in a blank portion where a thermal transfer layer is not provided on a base sheet. For example, one in which a margin is provided at an edge of the base sheet along the flow direction and a detection mark is provided in the margin, and another in which a thermal transfer layer is provided at intervals and a detection mark is provided in a margin generated between the thermal transfer layers ,and so on.

However, in any of the above cases and the above, if the relative position accuracy between the detection mark and the thermal transfer layer is not accurately maintained, the detection mark and the thermal transfer layer may overlap, and printing control must be strictly performed. Was.

In addition, when the detection mark is detected by detecting the hue of the detection mark, the hue of the thermal transfer layer causes a problem.

Furthermore, when there is no thermal transfer layer in the full width, the printable width becomes narrow.

[Problems to be solved by the invention]

The problem in the present invention is that, in the above-described prior art, the point of facilitating printing management for accurate positional accuracy when providing the detection mark, the point that hue of the thermal transfer layer is obstructed, and the printable width. Is in a narrow point.

[Means to solve the problem]

In the present invention, on a base sheet having a heat-resistant lubricating layer on the back surface, a thermal transfer layer of a plurality of colors made of a resin containing a dye which sublimates and moves by heating is provided in a face-to-face manner with no gap between the colors. The thermal transfer sheet has a detection mark for each color or each color set at a position overlapping with the thermal transfer layer in the thickness direction of the thermal transfer sheet, and the detection mark is provided between the thermal transfer layer and the base sheet or between the base sheet and the heat-resistant slide. The present invention solves the problem by providing the detection mark with an infrared light shielding property, and further, by laminating the thermal transfer layer over the entire width of the base sheet. It is a solution.

[Action]

In the present invention, in a thermal transfer sheet having a thermal transfer layer of a plurality of colors, the thermal transfer layer of the plurality of colors is provided without gaps between the colors, and at a position overlapping the thermal transfer layer in the thickness direction of the thermal transfer sheet, for each color or for each color. Since the detection marks are superimposed on each set, the thermal transfer sheet can be manufactured without any trouble without maintaining a particular positional accuracy.

Further, since the detection mark is made to have an infrared light shielding property, it is possible to detect the mark regardless of the color of the dye contained in the thermal transfer layer.

Further, by providing the thermal transfer layer over the entire width of the base sheet, the effective printing width can be increased.

〔Example〕

FIG. 1 is a plan view conceptually showing one embodiment of the thermal transfer sheet of the present invention. This thermal transfer sheet 1 is obtained by laminating a thermal transfer layer 3 on a base sheet 2; A plurality of color heat transfer layers capable of thermally transferring images of each color of magenta, cyan, and black (indicated by Y, M, C, and Bk in the figure) are repeatedly provided in this order without any gap between the colors, for forming a color image. Things. And the first
In the example shown in the figure, a detection mark is provided at one corner of the yellow thermal transfer layer, which is the head of each color combination.

FIG. 2 is a cross-sectional view taken along line AA of the thermal transfer sheet 1 of FIG. 1. In FIG. 2 (a), the thermal transfer sheet 1 is further above the thermal transfer layer 3 laminated on the base sheet 2. Detection mark 4
2 (b), a detection mark 4 is provided between the base sheet 2 and the thermal transfer layer 3 laminated thereon (in the above two cases, the detection mark 4 is The side of the base sheet where the thermal transfer layer is located is in contact with the thermal transfer layer.)

In FIG. 2 (c), the detection mark is provided on the side of the base sheet 2 where the thermal transfer layer 3 is not stacked only when the heat transfer layer 3 containing the dye which is transferred by heat is stacked on the base sheet 2. In the example of FIG. 2C, the heat-resistant lubricating layer 5
Is provided. 2A and 2B may be provided. 2 (b) and 2 (c) show an embodiment of the present invention.

As shown in FIG. 2 (b), a laminate obtained by laminating a base sheet / detection mark / thermal transfer layer in this order can be manufactured by using a coating machine or a printing machine having a plurality of coating or printing units on a base sheet only once. There are advantages.

As shown in FIGS. 2 (b) and 2 (c), in the case where the detection mark does not face the outermost surface, the detection mark does not wear during use and unevenness does not occur as a whole. There is an advantage that the detection mark portion does not swell even when wound in a large amount.

It should be noted that how many types of colors are selected for each thermal transfer layer (the number of colors), the order of each color, and the like can be arbitrarily determined, and are not limited to the examples shown in the drawings. The same applies to the embodiments shown in plan views below.

FIG. 3 is a plan view showing another embodiment of the thermal transfer sheet of the present invention, in which a plurality of thermal transfer layers are separately provided on a base sheet. Each of the planar structures shown in FIG. 3 has any one of the following laminated structures: a structure of a base sheet / detection mark / thermal transfer layer; a structure of a heat-resistant lubricating layer / detection mark / base sheet / thermal transfer layer. May be employed.

In the embodiment shown in FIG. 3, the thermal transfer layer is laminated over the entire width of the base sheet. In this way, there is no waste of the base sheet.
However, it is difficult to provide the thermal transfer layer over the entire width in terms of manufacturing. In the thermal transfer sheet as shown in FIG. 3, the margins on both sides along the flow direction are left as blanks when the thermal transfer layer is formed. The method of removing the portion is easier in manufacturing. Of course, without performing the slitter processing, the one shown in FIG. 3 may have margins on both edges (the upper and lower edges of each thermal transfer sheet in FIG. 3).

When the detection mark is not provided on the thermal transfer layer 3 (corresponding to FIGS. 2 (b) and 2 (c)), the presence of the detection mark does not affect the image to be thermally transferred. (B), or at the center of each color heat transfer layer as shown in FIG. 4 (b).

In the present invention, the material of the base sheet 2 preferably has heat resistance and strength, and paper, metal foil, and plastic film can be used. As a plastic film, polyester such as polyethylene terephthalate,
There are films such as polystyrene, polypropylene, polysulfone, polycarbonate, polyvinyl alcohol, cellophane, and polyamide. Usually, a film of polyethylene terephthalate is often used in consideration of heat resistance and mechanical strength.

The thickness of the base sheet 2 is 0.5 to 50 μm, preferably 3 to 1 μm.
It is about 0 μm.

The thermal transfer layer 3 in the present invention is made of a resin containing a dye which sublimates and migrates.

The dye contained in the thermal transfer layer is a heat sublimable disperse dye, an oil-soluble dye, or a basic dye having a molecular weight of 150.
~ 800, preferably 310-700. Among them, the selection is made in consideration of the thermal sublimation temperature, hue, weather resistance, solubility in the ink composition or the binder, and the like.

Examples of dyes include, for example: CI Disperse Yellow 51, 3, 54, 79, 60, 23, 7, 141, CI Disperse Blue 24, 56, 14, 301, 334, 165, 1
9, 72, 87, 287, 154, 26, CI Disperse Red 135, 146, 59, 1, 73, 60, 16
7, CI Disperse Violet 4, 13, 36, 56, 31 CI Solvent Violet 13, CI Solvent Black 3, CI Solvent Green 3, CI Solvent Yellow 56, 14, 16, 29, CI Solvent Blue 70, 35, 63, 36, 50, 49, 111, 1
05, 97, 11, CI Solvent Red 135, 81, 18, 25, 19, 23, 24, 1
43, 146, 182.

As the resin for the thermal transfer layer 3 in the present invention, any conventionally known resin can be used, and examples thereof include the following: Cellulose resins include ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxycellulose, hydroxypropyl cellulose, methyl cellulose, and acetic acid. Cellulose or cellulose acetate butyrate, as a vinyl resin, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetoacetal, polyvinyl pyrrolidone, or polyacrylamide.

Among these, polyvinyl butyral or polyvinyl acetoacetal is preferred in terms of heat resistance, dye transferability, and the like.

Besides these, ionomers obtained by ion-crosslinking an ethylene / acrylic acid copolymer with a metal can also be used.

Alternatively, when a compound having active hydrogen such as polyvinyl butyral, polyvinyl acetoacetal, polyvinyl formal, polyester polyol, or acrylic polyol is cross-linked with a polyisocyanate compound, the heat resistance of the heat transfer layer can be further improved, and the heat transfer sheet can be used. Suitable for running at low speed.

In order to form the thermal transfer layer 3, the above dye is dissolved together with a resin using a solvent to form an ink composition, and then an appropriate printing method such as gravure printing is used.

The weight ratio of dye to resin in the thermal transfer layer is dye / resin = 1/2
It is about 3/1. The thickness of the thermal transfer layer is 0.3 to 2 μm.
It is about.

The detection mark 4 may be made of any material as long as the presence of the mark can be confirmed by electrical, magnetic or optical detection means.

The information that the detection mark should have is: distinction between the front and back of the thermal transfer sheet, recording start position, distinction between head and tail (direction),
The type, grade, and number of frames that can be printed on one roll of the thermal transfer sheet, the remaining amount, a notice of the end of the thermal transfer sheet, or the boundary of each color thermal transfer layer, and the like.

In relation to the detection means, as a detection mark, for example,
A mark made of a conductive resin or metal foil containing metal powder or carbon in a resin and electrically detected, a mark formed by a magnetic composition containing a magnetic metal or a compound in a resin or a deposited film of a magnetic metal. There are a mark which is magnetically detected and a mark made of a composition containing a pigment or dye which can be distinguished by a light source to be used in a resin and which is optically detected.

Any of the detection means can be used,
What can be simplified as a device is a means for optically detecting.

When the thermal transfer layer of each color and the detection mark overlap in the same area, when the dye or pigment in the detection mark has a general hue, it is necessary to use an appropriate color filter. If a detection mark is selected as an infrared-transmitting mark and the detection mark is detected by infrared light as an infrared light-shielding mark, detection can be performed regardless of the hue of the thermal transfer layer.

The infrared light-shielding mark can be formed by a composition containing an infrared light-shielding substance in a resin. The most suitable infrared light-shielding substance is carbon black, which most easily absorbs infrared rays. As the resin containing the infrared light shielding material, polyurethane resin, polyamide resin, vinyl chloride / vinyl acetate copolymer resin, vinyl chloride / acrylic copolymer resin, cellulose acetate butyrate, etc. are suitable. Alternatively, they can be used as a mixture. These resins may be further crosslinked with a polyisocyanate compound.

When an infrared light-shielding substance is used, the weight ratio of the infrared light-shielding substance to the resin in the detection mark is infrared light-shielding substance / resin = 1/1 to 10/1, and the thickness is about 0.5 to 5 μm.

The configuration of the device that detects the detection mark of infrared light shielding
For example, it comprises an infrared projector such as an infrared light emitting diode and an infrared sensor disposed on one surface of a running thermal transfer sheet, a reflective plate disposed on the other surface of the thermal transfer sheet, and a computer connected to the infrared sensor. In this case, various operations are instructed to the printing apparatus based on a signal from the infrared sensor.

If you use an infrared projector that can emit infrared light with a wavelength of 900 to 2500 nm, especially 900 to 1000 nm, and an infrared sensor that is sensitive to the same wavelength range, the dye in the thermal transfer layer will not absorb infrared in this wavelength range. Irrespective of the hue, the infrared rays penetrate the thermal transfer layer, and the detection efficiency of the infrared light shielding detection mark increases. Therefore, as the dye in the thermal transfer layer, it is preferable to select and use a dye that substantially transmits infrared rays having a wavelength within the above range.

The reason why the detection efficiency of detecting the detection mark of the thermal transfer sheet of the present invention is excellent will be described using an example.

For example, an example in which a base sheet, a thermal transfer layer, and an infrared detection mark are provided in this order will be described.

As shown in FIG. 5 (a), when infrared rays are radiated from the upper side, that is, from the side of the thermal transfer layer by the projector, the detection mark 4
In the area without the heat transfer layer 3, the reflectivity of the surface of the thermal transfer layer 3 is considerably lower than the reflectivity of the base sheet.
After being incident as it is and emitted to the lower surface, reflected by the reflecting plate 6 and directed upward, a part of the light hits the base sheet and is reflected, resulting in a loss, and the rest is incident again and emitted upward. Therefore, there is only one chance of losing infrared light.

However, if the detection mark is provided in the margin of the base sheet as in the related art, as shown in FIG.
There is a chance that infrared light is lost once, a total of two times, when hitting the base sheet after reflection by the reflector.

The situation where the transmitted infrared light is lost as described above is the same when the infrared light is irradiated from below, that is, from the base sheet side.

That is, in the thermal transfer sheet of the present invention, as shown in FIG. 5 (c), the infrared light is greatly attenuated once, but in the conventional heat transfer sheet, as shown in FIG. Is greatly attenuated twice.

The detection marks are the same in FIGS. 5A and 5B, and the same in FIGS. 5C and 5D. In any case, the thermal transfer sheet of the present invention is The detection efficiency when detecting the detection mark is superior to the conventional thermal transfer sheet.

〔The invention's effect〕

According to the present invention, since the detection mark is provided so as to overlap with a certain position of the thermal transfer layer, it is not necessary to make the relative positional accuracy with the thermal transfer layer strict. Further, when the detection mark has an infrared light shielding property, the detection mark can be detected regardless of the color of the dye contained in the thermal transfer layer.

Furthermore, when the thermal transfer layer is provided over the entire width of the base sheet, the printing width can be maximized since there is no margin at all.

[Brief description of the drawings]

1, 3, and 4 are plan views of the thermal transfer sheet of the present invention, FIG. 2 is a cross-sectional view of the thermal transfer sheet of FIG. 1, and FIG. 5 is a view showing the operation of the thermal transfer sheet of the present invention. is there. 1: Thermal transfer sheet 2: Base sheet 3: Thermal transfer layer 4: Detection mark 5: Heat-resistant lubricating layer 6: Reflector

Continuation of the front page (56) References JP-A-60-120073 (JP, A) JP-A-60-139476 (JP, A) JP-A-61-37471 (JP, A) JP-A-62-179975 (JP) JP-A-59-230794 (JP, A) JP-A-60-8089 (JP, A) JP-A-59-45184 (JP, A) JP-A-61-51380 (JP, A) 61-192594 (JP, A) JP-A-60-242090 (JP, A) JP-A-61-83083 (JP, A) JP-A-61-93268 (JP, U) JP-A-59-139354 (JP, A) U) Japanese Utility Model Showa 60-17357 (JP, U) Japanese Utility Model Showa 61-31844 (JP, U)

Claims (3)

(57) [Claims] 1. A heat transfer layer of a plurality of colors made of a resin containing a dye which sublimates and transfers by heating is provided on a base sheet having a heat-resistant lubricating layer on the back side in a face-to-face manner with no gap between the colors. The thermal transfer sheet has a detection mark for each color or each color set at a position overlapping with the thermal transfer layer in the thickness direction of the thermal transfer sheet, and the detection mark is provided between the thermal transfer layer and the base sheet or between the base sheet and the heat-resistant slide. A thermal transfer sheet provided between the heat transfer layer and the heat transfer layer. 2. The thermal transfer sheet according to claim 1, wherein the detection mark has an infrared light shielding property. 3. The thermal transfer sheet according to claim 1, wherein the thermal transfer layer is laminated over the entire width of the base sheet.