JPH0386593A - Ink film for thermal transfer recording - Google Patents

Abstract

PURPOSE:To solve both of the coating properties of a printing part and the cutting thereof with good balance by mounting an ink layer formed by gathering numberless spot-like or linear ink bodies and providing gaps between the ink bodies. CONSTITUTION:An ink layer 10 is formed to a film 2 by gathering spot-like ink bodies 1 or linear ink bodies 1' over the entire surface of said film 2 and the area ratio occupying the surface of the film 2 of the ink layer 10 composed of the aggregate of the spot-like ink bodies 1 or linear ink bodies 1' is pref. 25 - 90% of the area of the film 2. The planar shape of each of the spot-like ink bodies 1 may be formed into various figurate shapes or various amorphous shapes. The short and long diameters thereof is pref. within a range of the longitudinal and lateral lengths of the surface of a rectangle and the dot-like ink bodies 1 forming the ink layer 10 are not limited to a specific arrangement mode and may be gathering of a regular arrangement state such as a lattice-like or zigzag arrangement state or an irregular arrangement state arranged at random.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ink film for thermal transfer recording, particularly an ink film that has excellent printability and can be used for ink ribbons suitable for thermal transfer printers for office automation equipment such as word processors.

[Conventional technology]

Thermal transfer recording ink film is mainly cut into ribbons and used as thermal transfer ink ribbons for printers of office automation equipment such as word processors, and has an ink layer uniformly formed on the surface of the film. It consists of an ink composition containing a heat-melting resin, a pigment such as carbon black, and the like.

Various improvements have been made in the thermal transfer printing technology using such thermal transfer recording ink films with the aim of achieving high resolution printing, high speed printing, and low rough surface printing.

In order to satisfy the above printing characteristics, ink coverage in the printing area and ink drainage in the printing area are required, but on the other hand, these two printing characteristics are contradictory characteristics for the ink layer, and it is necessary to solve these problems. In order to solve these problems at the same time, the ink layer is required to have ink characteristics that allow the heated and non-heated areas to be clearly distinguished within the ink layer.

However, in conventional thermal transfer recording ink films, a heat-melting ink layer is formed uniformly as a substantially continuous layer in all directions over the entire surface of the film, and the boundary between the heated area and non-heated area by the thermal head is It was difficult to clearly identify it, and it was difficult to achieve both coverage and cutting.

Therefore, in order to solve this problem, as a means to distinguish between heated parts and non-heated parts, for example,
m5ec or less), by peeling off the ink ribbon and the transfer paper, a method is taken to distinguish the heat-fused area from the non-heated area (Japanese Patent Application Laid-Open No. 64-72892), or by applying emulsion, etc. A means of forming a resin layer consisting of a discontinuous layer in an ink layer, forming a continuous layer formed into a film or highly agglomerated by heating, and a discontinuous layer, which is a non-heated part, in a short time to distinguish between the two. (Japanese Unexamined Patent Publication No. 62-27181) has been proposed, and these methods tend to improve the contradictory problems of the coverage of the printed area and the breakage of the printed area.

[Problem to be solved by the invention]

However, although all of the above thermal transfer recording ink films that have been proposed so far can distinguish heated parts and non-heated parts, in the case of (2) above, no matter what kind of differentiation is made, they end up having a certain thickness. The ultimate resolution is difficult to obtain because the ink must be cut off, and in the case of (2) above, there is actually a binder component such as wax between the resin particles, which impedes film-forming properties and eventually In the case of , the coverage of the printed part and the cut of the printed part are also called! It was still far from sufficient to solve the problem of IB at the same time.

Therefore, an object of the present invention is to provide an ink film for thermal transfer recording that solves both the coverage of the printed area and the breakage of the printed area in a well-balanced manner, and enables high-resolution printing, high-speed printing, and printing on rough surface paper. .

[Means to solve the problem]

As a result of various studies regarding the coverage of the printed area and the breakage of the printed area, the present inventors found that the above problem can be solved by forming an ink layer in a specific form on the film.

The present invention has been made based on the above findings, and is characterized by comprising an ink layer made up of numerous dotted or linear ink bodies, and having voids between each of the ink bodies. The present invention provides an interfilm for thermal transfer recording.

The dotted ink bodies 1 in the present invention are formed substantially as dots on the surface of the film 2 by the ink composition, and the dotted ink bodies 1 may be formed in either a regular or irregular shape. The arrangement of the ink layer 10 made up of the dotted ink bodies 1 may be either regular or irregular. As an example of regularly arranging fixed-shaped dotted ink bodies 1, for example, as shown in FIGS. Examples include those arranged in a shape. In addition, even when the dotted ink body 1 is formed into a regular shape, its shape and size are not limited and vary depending on the purpose. Size of dotted ink body (length x width)
is usually 10-200μm x 10-200μm, height h
is a rectangular body with a size of 1 to 20 μm. Incidentally, such a rectangular body is an ideal shape, and if this rectangular body is in a collapsed shape or in other shapes, the size should be according to the height and volume of the dotted ink body l. and shape.

Further, each of the dotted ink bodies 1 is formed independently as shown in FIGS. 1 and 2, and a gap δ is formed between each of the dotted ink bodies 1.

The distance of the gap δ varies depending on physical properties such as a concentration of the ink composition or printing factors such as the dot density of the thermal head. For example, in the case of an ink ribbon for thermal transfer of a printer such as a word processor, Usually, it is 1 to 50 μm. In other words, the gap δ may be appropriately determined in consideration of the target dot density of the printer, print size, etc. Also, each dotted ink body!
may be connected to each other via an interface with weak cohesive force on the surface of the film 2, in short, the ink 11i1
It is sufficient that the dotted ink body 1 is configured to be easily cut between the dotted ink bodies 1 through the gap δ between the dotted ink bodies 1.

In addition, when the ink layer consists of multiple ink layers,
It is sufficient that the dotted ink bodies 1 are present in at least the uppermost ink layer, and that the 3 g dotted ink bodies 1 of the uppermost layer are arranged with gaps δ interposed therebetween as described above.

Further, as an example of irregularly arranging dotted ink bodies 1 having irregular shapes, there is, for example, the one shown in FIG. , it suffices if the size of the printed character satisfies an appropriate range, and it suffices if it is formed to match the shape of the dotted ink bodies 1. In addition, in this case, the dotted ink body l
The size of one planar shape is usually within a range of ±50% with respect to the size of the planar shape of the above-mentioned regular rectangular body.

Further, the linear ink bodies 1'' in the present invention may be formed in either a regular or irregular shape, similar to the dotted ink bodies 1, and are composed of a collection of the linear ink bodies 1''. The arrangement of the ink layer 10 may be either regular or irregular. For example, as shown in FIG. Those arranged perpendicularly, those arranged randomly with the dimensions shorter than the width direction of the film, those arranged parallel to the longitudinal direction of the film 2, those arranged at an angle, and these are arranged at right angles. In addition to a randomly mixed arrangement, a similar arrangement of curved ink bodies may be used. Also, a gap δ is formed between each of the linear ink bodies l°. Therefore, the linear ink body 1'' can be seen as a combination of the dotted ink bodies 1 as appropriate, and the height h of the central portion and the distance of the gap δ are determined by the dotted ink bodies 1, respectively. 1.

Further, each of the linear ink bodies l'' is different from the dotted ink body 1.
Similarly, the ink composition may be in contact or bonded through an interface having a weak cohesive force.

Further, when the ink 1i110 is composed of a plurality of ink layers, each linear ink body 1'' is present in at least the uppermost ink layer, and the linear ink body 1' of the uppermost layer is similar to the above. It is sufficient if they are arranged with a gap δ interposed therebetween.

As mentioned above, the ink layer 10 in the present invention is a film? The ink layer 10 is formed by an aggregation of the dotted ink bodies 1 or the linear ink bodies l'' over the entire surface of the ink layer. The area ratio occupied on the surface of the film 2 is preferably 25 to 90% of the area of the film 2.

As the ink & 11 materials forming the ink layer 10, conventionally known ink materials can be used, but resin inks with good film-forming properties and high cohesive strength are preferred.

As mentioned above, the planar shape of each dotted ink body l is not limited to a specific shape, and may be formed into various regular shapes or various irregular shapes. However, it is preferable that the short axis and long axis thereof are within the range of the vertical and horizontal lengths of the surface of the rectangular body, and each of the dotted ink bodies forming the ink N10 1 is not limited to a specific arrangement mode, and may be a set of irregular arrangement states, such as a lattice shape as described above, a regular arrangement state such as a zigzag pattern, or a randomly arranged irregular arrangement state. Good too.

Further, the planar shape of each of the linear ink bodies 1' may be such that the line width is uniform or non-uniform, or may have a different line width. They may be mixed.

Further, each of the linear ink bodies 1' forming the ink layer 10 is not limited to a specific regular arrangement, and may be arranged at random, in addition to the above-described arrangement perpendicular to the longitudinal direction. It may be arranged in an irregular manner.

As explained above, when the ink film for thermal transfer recording of the present invention has a countless number of dotted ink bodies 1, when each dotted ink body I is pressed and heated by the thermal head, the heating range shown in FIG. A plurality of dotted ink bodies 1 in 3
is melted, and as shown in FIG. 5, each dotted ink body 1 fills each gap δ and forms a film within the heating range 3 to form an ink coating film. On the other hand, the non-heated part remains in a state where there is a gap δ between the dotted ink bodies 1, and the ink coating film is discontinuous with each adjacent dotted ink body 1 through the gap δ. Therefore, it is easily separated from the non-heated part, peeled off from the film, and transferred to the paper surface, and has excellent coverage and cutting of the printed area, achieving high-resolution printing, high-speed printing, and printing on rough surface paper. . Further, in the ink film for thermal transfer recording of the present invention, the print quality is better when the ink dots 1 are formed using an ink composition having excellent film-forming properties. Furthermore, the ink film for thermal transfer recording of the present invention having numerous linear ink bodies can also provide the same effects as those having dotted ink bodies.

[Effect]

According to the ink film for thermal transfer recording of the present invention, when the ink film is heated by the thermal head, the heated dotted or linear ink bodies melt and form a uniform ink coating within the heated area, leaving no gaps. It is reliably separated from the collection of other ink bodies that have passed through the ink, peeled off from the film, and printed on the paper surface.

[Examples] Next, the present invention will be explained based on the following examples, but the present invention is not limited to the following examples.

Example 1 The solvent-based ink composition shown in Table 1 was applied to PE with a film thickness of 3.5 μm.
An ink film for thermal transfer recording was produced by printing on a T film 2 and arranging dotted ink bodies 1 as a lattice-like independent dot pattern (ink layer 10) shown in FIGS. 1 and 2 (dotted ink). Body: approx. 50μm x approx. 50μm, gap: 5μ
around m, maximum dry coating thickness: 4 μm). This film 1
An ink ribbon cassette is created by cutting an ink ribbon with a width of 2.7 s and loading it into a cassette, and then inserting this ink ribbon cassette into a commercially available personal word processor (Matsushita Electric Industrial Co., Ltd. Ulpr) equipped with a 48-dot thermal head.
o-501), and the printing of the ink ribbon was evaluated. When evaluating, use BEKK Lancaster bond paper with a smoothness of 3 seconds and a 4×4 paper with a dot area ratio of 44.4%.
Dot halftone dots were printed and the printed area ratio was measured. The results are shown in Table 2.

Comparative Example 1 An ink sheet was prepared in the same manner as in Example 1, except that an ink layer with a uniform film thickness (dry coating thickness of 4 μm) was formed on Film 2, and the same printing evaluation as in Example 1 was performed. . The results are shown in Table 2.

According to the results shown in Table 1, Table 2, and Table 2 above, the thermal transfer recording ink film of Example 1 had a halftone dot area ratio that was extremely close to the set halftone dot area ratio, a sharp print area, and a high It can be seen that high-resolution printing is obtained in terms of coverage.

On the other hand, the thermal transfer recording ink film of Comparative Example 1 had too strong a film-forming property and had poor separation between heated and non-heated areas, resulting in transfer of non-heated areas as well, resulting in printing with poor resolution. It can be seen that

From these results, the demands for high coverage and high resolution, which were originally difficult to meet, can be largely solved by applying the ink film for thermal transfer recording of the present invention, and that the ink film for thermal transfer recording of the present invention can achieve high quality. It can be seen that printing can be achieved.

The ink film for thermal transfer recording of the present invention may have regular or irregular voids dispersed and arranged over the entire surface of the ink layer.

Further, in the ink film for thermal transfer recording of the present invention, the coating thickness of the ink layer is, for example, several tens of thousands for word processors.
It may be configured to change in all directions at a pitch of μm.

Further, the ink film for thermal transfer recording of the present invention may be formed by making each ink body contact with each other through an interface with weak cohesive force, and in this case, there is a gap between the interfaces of each ink body. may be formed.

Even if the ink film for thermal transfer recording consists of any of the forms described above, it is possible to expect the same functions and effects as the ink film for thermal transfer recording of the present invention described above.

〔Effect of the invention〕

The ink film for thermal transfer recording of the present invention solves both the coverage of the printed area and the breakage of the printed area in a well-balanced manner, and is capable of high resolution printing, high speed printing, and low roughness printing, and is particularly suitable for OA applications such as word processors. It is suitable as an ink ribbon for thermal transfer in equipment printers.

[Brief explanation of drawings]

FIG. 1 is an enlarged plan view showing an ink film for thermal transfer recording according to an embodiment of the present invention, FIG. 2 is a perspective view showing the ink film for thermal transfer recording shown in FIG. 1, and FIG. FIG. 4 is a plan view corresponding to FIG. 1 showing an ink film for thermal transfer recording according to yet another embodiment of the present invention, and FIG. 5 is a plan view corresponding to FIG. 1 is a plan view corresponding to FIG. 1 showing a heated state of the thermal transfer recording ink film shown in FIG. 1. FIG.

Claims (1)

[Claims] 1. An ink film for thermal transfer recording, comprising an ink layer made up of numerous dotted or linear ink bodies, and having voids between each of the ink bodies.