Ink ribbon

Abstract

 Provided is an ink ribbon having a large resistance against hitting and offering an extended life which includes warp yarns (1) and weft yarns (2), wherein the warp yarns (1) are thinner than the weft yarns (2), or the picking density of the weft yarns (2) is larger than that of the warp yarns (1).

Description

[0001] The present invention relates to an ink ribbon and, more particularly, to an ink ribbon which has a large resistance against hitting for printing and is capable of extending the life of its cloth.

[0002] In the present invention, the resistance against hitting for printing (hereinafter referred to as "hitting resistance" simply) is meant by the number of hits for printing characters until a hole of 0.3 mm or more in diameter is made in the hit portion of an ink ribbon on the condition that hitting for printing 10 characters on one line is repeatedly carried out with the ink ribbon kept stationary. In this case the size of one character is 3 to 4 mm, and the number of hits is counted on a NLQ-mode printing basis.

[0003] Conventionally, endless ink ribbons and seamless ink ribbons for use with a printer or the like, in general, have employed a weave structure of plain, twill, sateen or the like.

[0004] Fig. 7 is an explanatory plan view of such a conventional ink ribbon, while Fig. 8 is an explanatory sectional view of the same. The conventional ink ribbon of a plain weave structure is obtained by weaving the warp 11 and weft 12 each composed of synthetic fibers such as nylon, polyester and rayon, natural fibers or the like to form a cloth and heat-cutting the cloth to a width of a desired ink ribbon. In the present invention the warp is meant by a yarn extending perpendicular to the advancing direction of the ink ribbon.

[0005] In the conventional ink ribbon, however, yarns of the same thickness are used for both the warp and the weft and, furthermore, respective picking density of the two are substantially the same. For this reason, in the sectional structure of the ink ribbon the warp is outstandingly protruded from the surface of the weft as shown in Fig. 8. When the surface of the ink ribbon is subjected to printing with a dot pin 13, the dot pin 13 comes into direct contact with the warp 11 with a high probalility. Consequently the warp 11 of which the strength is lessened because of heat-cutting at both ends thereof during manufacturing of the ink ribbon is prone to be cut off at a relatively early stage. Specifically, the dot pin 13 moving to the right and left is likely to scratch the warp 11 thereby exerting a substantial force thereon. As a result, the warp 11 is cut off with the weft 12 possibly cut, whereby the ink ribbon is no longer usable. Thus, the hitting resistance of the conventional ink ribbon depends on durability of the warp 11 and, hence, it is difficult to improve the hitting resistance.

[0006] In view of the foregoing, it is an object of the present invention to provide an ink ribbon having an increased hitting resistance and offering an extended life.

[0007] According to the present invention, there is provided an ink ribbon comprising warp yarns extending perpendicular to a direction in which the ink ribbon advances, and weft yarns extending parallel to the direction, wherein (1) the warp yarn is thinner than the weft yarn, or (2) picking density of the weft yarn is larger than that of the warp yarn.

Fig. 1 is an explanatory plan view showing one embodiment of an ink ribbon according to the present invention;

Fig. 2 is an explanatory sectional view of the embodiment shown in Fig. 1;

Fig. 3 is an explanatory plan view showing another embodiment of an ink ribbon according to the present invention;

Fig. 4 is an explanatory sectional view of the embodiment shown in Fig. 3;

Fig. 5 is an explanatory plan view showing still another embodiment of an ink ribbon according to the present invention;

Fig. 6 is an explanatory sectional view of the embodiment shown in Fig. 5;

Fig. 7 is an explanatory plan view showing a conventional ink ribbon; and

Fig. 8 is an explanatory sectional view of the ink ribbon shown in Fig. 7.

[0008] Hereinafter, an ink ribbon according to the present invention will be described in detail with reference to the drawings.

[0009] Fig. 1 is an explanatory plan view showing an embodiment of an ink ribbon according to the present invention, wherein a plain weave structure is employed. A warp yarn 1 and a weft yarn 2 are each composed of synthetic fibers such as nylon, polyester and rayon, natural fibers, or like fibers. The warp yarn 1 and weft yarn 2 are woven with a usual weaving machine. The warp yarn 1 is thinner than the weft yarn 2, and is preferably woven at a relatively high tension. In contrast, the weft yarn 2 is thick relative to the warp yarn 1, and is preferably woven at a relatively low tension. Concretely, the warp yarn 1 is usually 30 to 50 deniers, while the weft yarn 2 is usually 30 to 150 deniers. Preferably, the weft yarn 2 is about 1.1 to 3 times, especially about 1.5 to 2.2 times as thick as the warp yarn 1. By such design, the warp yarn 1 is set back from the surface of the ink ribbon in section, as shown in Fig. 2.
Consequently, the probability that a dot pin 3 comes into direct contact with the warp yarn 1 is reduced and, hence, the hitting resistance of the ink ribbon can be improved.

[0010] Alternatively, such probability can also be reduced by making the picking density of the weft yarn 2 larger than that of the warp yarn to increase the proportion of the weft yarn 2 to the whole woven cloth. When the ink ribbon as shown in Fig. 2 is thus fabricated, the areal proportion of the weft yarn 2 to the whole surface area of the ink ribbon can be increased. The picking densities of the warp yarn 1 and weft yarn 2 are usually 100 to 180 yarns/inch and 110 to 500 yarns/inch, respectively. Preferably, the picking density of the weft yarn 2 is about 1.1 to 3 times, especially about 1.5 to 2.2 times as large as that of the warp yarn 1. In this case too, the probability that the dot pin 3 comes into direct contact with the warp yarn 1 is reduced and, hence, the hitting resistance of the ink ribbon can be improved.

[0011] An experiement was conducted on ink ribbons of the structure shown in Figs. 1 and 2 wherein respective thickness and picking densities of the warp yarn 1 and weft yarn 2 were set as in Table 1. As a result, the hitting resistance of the ink ribbon according to the present invention was found to be greatly improved as compared with the conventional ink ribbon. Note that in this experiment a yarn of nylon 6,6 was used for both the warp yarn 1 and the weft yarn 2, and the hitting resistance was evaluated in a relative value of the total number of hits, with that of the conventional ink ribbon assumed 1.

Table 1

	Warp yarn		Weft yarn		Hitting resistance
	Thickness (denier)	Picking density (yarns/inch)	Thickness (denier)	Picking density (yarns/inch)
Ex. 1	40	114	70	114	2
Ex. 2	40	122	40	210	1.25
Comp. Exp.	40	146	40	148	1

[0012] Figs. 3 and 4 are explanatory plan view and explanatory sectional view, respectively, of another embodiment of an ink ribbon according to the present invention. In this embodiment a twill weave structure is employed. Like the embodiment shown in Figs. 1 and 2, this embodiment is of a sectional structure wherein the areal proportion of the weft yarn to the surface area of the ink ribbon is large as compared with the conventional ink ribbon. Therefore, the probability that the dot pin comes into direct contact with the warp yarn is reduced.

[0013] Figs. 5 and 6 are explanatory plan view and explanatory sectional view, respectively, of still another embodiment of an ink ribbon according to the present invention. This embodiment employs a sateen weave structure and exhibits an effect similar to those of the preceding embodiments.

[0014] It is to be noted that the embodiments shown in Figs. 3 to 6 need to be hit on the side having a smaller proportion of the warp yarn in the surface area of the ink ribbon.

[0015] Although the ink ribbon of the present invention has been described by way of the embodiments respectively having plain, twill and sateen weave structures, the present invention is not limited to such embodiments and can, of course, employ other weave structures.

[0016] As has been described, in the ink ribbon of the present invention the proportion of a weft yarn in the surface area of the ink ribbon is increased by using a warp yarn thinner than the weft yarn or making the picking density of the warp yarn smaller than that of the weft yarn. For this reason, the probalility that a dot pin comes into direct contact with the warp yarn can be remarkably reduced as compared with the conventional ink ribbon. Thus, it is less likely that a dot pin moving to the right and left scratches the warp yarn thereby exerting a large force thereon. Hence, the hitting resistance can be greatly improved. Thus, the ink ribbon can offer an extended life and, further, if it is supplied with ink by reinking, the life thereof for printing can also be made longer than that of the conventional ink ribbon.

[0017] Though several embodiments of the present invention are described above, it is to be understood that the present invention is not limited only to the above-mentioned, various changes and modifications may be made in the invention without departing from the spirit and scope thereof.

Claims

1. An ink ribbon comprising warp yarns extending perpendicular to a direction in which the ink ribbon advances, and weft yarns extending parallel to the direction, the warp yarns being thinner than the weft yarns.

2. The ink ribbon of Claim 1, wherein said weft yarns are 1.1 to 3 times as thick as said warp yarns.

3. An ink ribbon comprising warp yarns extending perpendicular to a direction in which the ink ribbon advances, and weft yarns extending parallel to the direction, a picking density of the weft yarns being larger than that of said warp yarns.

4. The ink ribbon of Claim 3, wherein said picking density of said weft yarns is 1.1 to 3 times as large as that of said warp yarns.

Drawing