JPH05162469A - Transfer sheet - Google Patents

Abstract

PURPOSE:To form a high-quality picture excellent in reproducibility of the picture by constituting a transfer sheet of a base body and a transfer layer containing thermoplastic resin provided on the base body and regulating the average roughness in the centerline on the surface of the transfer layer to the specified value and also regulating the smoothness in the transfer layer side of the base body to the specified Bekk smoothness. CONSTITUTION:In a heat transfer sheet 1 constituted of both a base body and a transfer layer 2 containing thermoplastic resin (e.g. ethylene-vinyl acetate copolymer resin) provided on the base body 3, the average roughness in the centerline on the surface of the transfer layer 2 is regulated to 0.1-2.5mum and also the smoothness in the transfer layer 2 side of the base body 3 is regulated to >=200 seconds Bekk smoothness. Further thickness of the transfer layer 2 is regulated to 15-60mum. A high-quality picture excellent in reproducibility of the picture can be obtained by using the transfer sheet. It is especially effective in a high precise pattern and also excellent in reproducibility of dots in a dot pattern. Therefore, a picture can be obtained which is excellent in half tone good in reproducibility of gradation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer sheet which can be transferred onto a cloth or the like by heating. The present invention particularly transfers a transfer image obtained by thermal transfer onto a transferable layer using a thermal transfer type printer, typewriter, word processor, etc. to a final transfer target such as cloth by heating. The present invention relates to a transfer sheet that can be used.

[0002]

2. Description of the Related Art An image is formed on a transfer sheet having a transfer layer provided on a substrate, and the transfer layer having the image formed thereon is then applied to a cloth to be transferred such as clothes using an iron or a hot press. BACKGROUND ART Techniques for forming a desired image on a cloth to be transferred like an appliqué by heating and pressurizing and finally peeling off the substrate have been widely known.

In recent years, a printer using a fusion type thermal transfer system,
Monochrome or color printing and printing devices such as typewriters and word processors have been developed, and various types of small-sized personal to business devices are commercially available.
In order to print or print with such a device, the thermal transfer ink ribbon is brought into close contact with a predetermined printing paper, a predetermined heating element such as a thermal head is caused to generate heat, and the thermal transfer ink of the thermal transfer ink ribbon is transferred to the printing paper. .. Such printing and printing methods are widely used in word processors because they are simple and inexpensive, have high image robustness, and are easy to maintain.

Further, when such a printing apparatus is used, a desired input image can be selected and can be recorded and stored in the same manner as a photograph, and a desired image and design can be created, so that the design field, personal taste, It can also be used in fields that show originality according to taste. Furthermore, the printed image output at this time is pasted, or the image is output on the printed image that has been pasted in advance, and this is re-applied to a desired portion such as a fiber rough surface of cloth, It is also used to exert fashionable elements such as appliqué.

Conventionally, as a method of applying to an application target having a rough surface such as cloth, a transfer layer made of a hot melt adhesive is provided on a substrate, and an arbitrary image is printed in a reverse pattern on the transfer layer. Method (JP-A-60-187598)
However, this method is not sufficient in image reproducibility such as dots not being transferred accurately. Further, JP-A-2-305689 discloses a transfer sheet in which the reproducibility of an image is improved by defining the surface roughness of a transfer layer provided on a substrate.

However, the above-mentioned transfer sheet still has insufficient transferability of ink, and it is not possible to obtain a highly accurate printed matter especially when the softening temperature of the transfer layer is low.

An object of the present invention is to provide a transfer sheet capable of forming a high quality image having excellent image reproducibility.

[0008]

As a result of various studies on the above problems, the present inventors have found that the roughness of the transfer layer surface as well as the smoothness of the substrate are limited within a predetermined range to obtain excellent image reproducibility. The present invention has been completed based on the finding that the above can be obtained.

The present invention is a thermal transfer sheet comprising a substrate and a transfer layer containing a thermoplastic resin provided on the substrate, wherein the center line average roughness of the surface of the transfer layer is 0.1 to 2.5 μm.
and a smoothness on the transfer layer side of the substrate of Beck smoothness of 200 seconds or more.

The present invention will now be described in detail with reference to the accompanying drawings.

As shown in FIG. 2, the transfer sheet 1 of the present invention.
Is basically composed of a substrate 3 and a transfer layer 2 provided on the substrate, and the transfer layer 2 contains a thermoplastic resin. In order to form an image using the cloth transfer sheet, as shown in FIG. 1, a fusion type thermal transfer ink ribbon 4 is superposed on the surface of the transfer layer 2 and the ink ribbon 4 is pressure-bonded by using a thermal head 5.
The ink 6 is heated and melt-transferred onto the surface of the transfer layer 2 according to the image. Next, make the formed image a reverse image,
Transfer to a cloth to obtain the desired image.

As shown in FIG. 3, the transfer to the cloth is performed by stacking the image forming surface of the transfer sheet 1 and the cloth 7 to be transferred in contact with each other, and heating the base 3 with an iron or a hot press. The transfer layer 2 is transferred to the transferred cloth 7. Finally the base 3
An image is formed on the transferred cloth 7 by peeling off only the cloth.

The transfer layer surface of the transfer sheet 1 of the present invention which is not in contact with the substrate 3, that is, the image forming surface, has a center line average roughness of 0.1 to 2.5 μm, preferably 0.1 to 1.0 μm. is there. Here, the center line average roughness is defined in JIS-B-0601. That is, a portion of the measurement length L is extracted from the roughness curve in the direction of its center line, the center line of the extracted portion is taken as the X axis, the direction of longitudinal magnification is taken as the Y axis, and the roughness curve is taken as y = f.
When expressed by (x), the value Ra (μm) obtained by the following formula
Say.

[0014] Ra = (1 / L) × ∫ 1 0 | f (x) | dx In the present invention, the cut-off value of the roughness curve and 0.8 [mu] m.

The center line average roughness of the transfer layer base surface is 2.5 μm.
If it is larger, the transfer layer 2 and the ink 6 do not come into close contact with each other, so that the image is missing and the image reproducibility deteriorates. In this way, if the center line average roughness is within the above range, the ink 6
Since the contact area of the image forming surface is controlled, the conventional problems can be solved and a wide range of materials can be selected as the transfer layer 2. Further, when the ink 6 is melt-transferred onto the image forming surface, the ink 6 flows into the unevenness of the image forming surface and firmly adheres to the image forming surface, so that the secondary effect of improving the abrasion resistance of the image is also obtained. ..

Further, in the transfer paper of the present invention, it is necessary that the base paper or plastic film has a high smoothness, and the transfer layer side base surface has a Beck smoothness of 200.
It has a smoothness of more than a second. When the substrate has such smoothness, excellent image reproducibility can be obtained.

The Beck's smoothness referred to here is the value obtained by the rate at which air leaks between the paper surface or the film surface and the flat surface that is completely flat and comes into contact with the flat surface under a constant pressure. -Measured according to the measuring method of P8119. If the smoothness is 200 seconds or less, the surface roughness of the substrate adversely affects printing, making it difficult to reproduce fine lines and dots.

The material used for the transfer layer of the present invention may be any material as long as it is easily melted by heating with an iron, a hot press or the like and transferred to the transfer cloth, and is appropriately selected based on the heating temperature. For example, as the base polymer, one or more of low density polyethylene, medium density polyethylene, ethylene-vinyl acetate copolymer, ethylene / acrylate copolymer resin, ionomer resin, polyamide resin, saturated polyester resin may be used depending on the purpose. Adopted. In particular, ethylene-vinyl acetate copolymer resin has excellent adhesiveness, flow characteristics, weather resistance, compatibility with multiple components, low-temperature transferability, etc., and low-density polyethylene has chemical resistance, weather resistance, and wash resistance. Both are preferable because they have excellent properties. If necessary, various known modifiers or additives may be added to the base polymer, for example, petroleum resin, rosin resin, tackifier such as terpene resin, or various plasticizers, You may add a softening agent, a filler, an antioxidant, an ultraviolet absorber, etc.

The thickness of these transfer layers is preferably 15 to 60 μm. If the thickness of the transfer layer is smaller than this, the transfer layer will not effectively flow into the fibers of the cloth to be transferred when it is heated and transferred, and the transferability will be low. On the other hand, if the layer thickness of the transfer layer is larger than this, the amount of resin to be transferred becomes too large,
The appearance of the image-formed cloth is poor and the feeling of discomfort increases. The substrate of the transfer sheet of the present invention may be in the form of a sheet having a function of holding the transfer layer and having heat resistance against an iron, a hot press or the like. Examples of such plastic film include films of polyester, polycarbonate, polyimide, polyphenylsulfone, and the like, and examples of cellulose fiber paper include high-quality paper,
Examples include, but are not limited to, art paper, coated paper, glassine paper, imitation paper, impregnated paper, and the like. The thickness of the substrate is not particularly limited, but usually 50 to 200 μm is preferable.

In the conventional transfer sheet, only the roughness of the surface of the transfer layer was taken into consideration, and the surface roughness of the base paper and plastic film was not taken into consideration.
For this reason, when printing is performed by applying a printing pressure by a fusion type thermal transfer type printing device using a transfer sheet having a low smoothness of the substrate, the smoothness of the substrate is more affected than the roughness of the thermoplastic resin layer of the transfer layer. It seems that That is, it is speculated that the transferability of the ink was insufficient when a substrate having a low smoothness was used, and the image reproducibility was insufficient especially for a highly accurate printed matter.

[0021]

By using a substrate having a center line average roughness of 0.1 to 2.5 μm on the side of the transfer layer which is not in contact with the substrate, that is, the image forming surface side, and having a Beck's smoothness of at least 200 seconds, the melt type thermal transfer ink When the ink is transferred from the ribbon to the image forming surface of the transfer layer, the transfer loss of the recesses due to the waviness of the substrate is reduced and extremely good image reproducibility can be obtained.

[0022]

EXAMPLES Next, the present invention will be described more specifically based on examples. The present invention is not limited to this embodiment.

Example 1 An ethylene-vinyl acetate copolymer resin (melt flow rate 15 dg / min, vinyl acetate content 14% by weight) was applied to a T-type extruder using a screw extruder.
Extruded from die (thickness 50 μm, extrusion temperature 1
40 ° C). Next, glassine paper with the resin softened
(Beck smoothness of about 300 to 400 seconds, 80 g / m ² ) was passed between the two rolls. The rolls consisted of a metal cooling roll that was in contact with each other and a metal dull roll whose surface was processed into a semi-matte shape, and the extruded resin was passed so as to be in contact with the metal dull roll. The center line average roughness of the image forming surface of the obtained transfer sheet was 0.7 to 0.8 μm.

A halftone dot pattern formed by one dot and a line formed by one dot are formed by using a color printer capable of printing with a thermal head having a resolution of 300 dpi (dots / inch) using these transfer papers. When the pattern was printed, it was confirmed that the dot pattern was reproduced almost uniformly.

Example 2 A low density polyethylene resin (melt flow rate 8 dg / min) was extruded from a T-die using a screw type extruder (thickness 30 μm, extrusion temperature 190 to 220 ° C.). Then, in the softened state of the resin, a white polyester film (Beck smoothness of about 2
000 seconds, thickness 75 μm) and passed between two rolls. The rolls consisted of a metal cooling roll that was in contact with each other and a metal dull roll whose surface was processed into a semi-matte shape, and the extruded resin was passed so as to be in contact with the metal dull roll. The center line average roughness of the image forming surface of the obtained cloth transfer sheet was 0.7 to 0.8 μm.

Using these transfer papers, a dot pattern formed of 1 dot and a line pattern formed of 1 dot were printed using a color printer capable of printing with a thermal head having a resolution of 300 dpi. However, it was confirmed that the dot pattern was uniformly reproduced. This transfer sheet was better than that of Example 1.

[Comparative Example 1] In the same manner as in Example 1, an ethylene-vinyl acetate copolymer resin was extruded from a T die using a screw type extruder. Then, with the resin softened, paper with Beck smoothness of about 70 seconds (grammage 90 g / m 2
² ) with two rolls. The rolls consisted of metal cooling rolls in contact with each other and metal dull rolls whose surface was processed into a semi-matte shape, and the extruded resin was passed so as to be in contact with the metal dull rolls. The center line average roughness of the image forming surface of the obtained cloth transfer sheet was about 0.7 to 0.8 μm as in Example 1. Using this transfer paper, a color printer capable of printing with a thermal head having a resolution of 300 dpi was used to print a dot pattern formed of 1 dot and a line pattern formed of 1 dot. A lot of blanks were seen and the print density was decreased. Although the smoothness of the resin surface is fairly good, it is considered that the large undulations of the base paper adversely affect the printability.

[Comparative Example 2] In the same manner as in Example 1, an ethylene-vinyl acetate copolymer resin was extruded from a T die using a screw type extruder. Then, with the resin softened, paper with Beck smoothness of about 500 seconds (grammage 95 g /
m ² ) with two rolls. The roll is composed of a metal cooling roll in contact with each other and a metal dull roll having a matte surface roughened more than the semi-matte dull roll used in Examples 1 and 2 and Comparative Example 1, and the extruded resin is a metal. I passed it so that it touched the dull rolls. The center line average roughness of the image forming surface of the obtained cloth transfer sheet was 3 to 4 μm. 3 using these transfer papers
When a color printer capable of printing with a thermal head having a resolution of 00 dpi was used for printing, dot patterns were frequently generated, and sufficient image reproducibility was not obtained.

Comparative Example 3 In the same manner as in Example 1, an ethylene-vinyl acetate copolymer resin was extruded from a T die using a screw type extruder. Then, with the resin softened, paper with Beck smoothness of about 800 seconds (grammage 70 g /
m ² ) with two rolls. The roll consisted of a metal cooling roll and a mirror-finished metal roll which were in contact with each other, and the extruded resin was passed so as to come into contact with the mirror-finished metal roll. The center line average roughness of the image forming surface of the obtained cloth transfer sheet was less than 0.1 μm.

A halftone dot pattern formed of 1 dot and 1 using a color printer capable of printing with a thermal head having a resolution of 300 dpi using these transfer papers
When I printed a line pattern formed by dots,
The printed portion was extremely excellent in image reproducibility, but during printing, a running defect was considered to be caused by the frictional force between the ink paper and the transfer paper. Since this transfer sheet has extremely high smoothness, the contact area between the ink paper and the transfer paper surface is very large. Therefore, when a pattern having a relatively large printing screen area such as a solid pattern is printed, it becomes difficult for the ink paper to separate from the surface of the transfer paper. It seems to end up. Therefore, if the surface of the transfer paper is too smooth, a good image can be obtained, but troubles in the running system are likely to occur.

[0031]

The transfer sheet of the present invention provides a high quality image with good image reproducibility. These are particularly effective for high-definition patterns and have excellent dot reproducibility of halftone dot patterns. Therefore, it is possible to obtain an image having excellent halftone with good gradation reproducibility.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing thermal transfer using the transfer sheet of the present invention.

FIG. 2 is a schematic cross-sectional view showing a transfer sheet of the present invention.

FIG. 3 is a cross-sectional view showing transfer of the transfer layer of the transfer sheet of the present invention onto a cloth.

[Explanation of symbols]

 1 Transfer Sheet 2 Transfer Layer 3 Base 6 Ink 7 Transfer Cloth

Claims (3)

[Claims] 1. A thermal transfer sheet comprising a substrate and a transfer layer containing a thermoplastic resin provided on the substrate, wherein the center line average roughness of the surface of the transfer layer is 0.1 to 2.5 μm, Moreover, the smoothness of the transfer layer side of the substrate is Beck smoothness of 200.
A transfer sheet characterized by being over a second. 2. The thermoplastic resin is an ethylene-vinyl acetate copolymer resin or a low density polyethylene resin.
The transfer sheet described. 3. The transfer sheet according to claim 1, wherein the transfer layer has a thickness of 15 to 60 μm.