Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Including interlaminar mechanical fastener
Patent
1994-05-03
1996-07-09
Ryan, Patrick J.
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Including interlaminar mechanical fastener
428220, 428221, 428195, 428378, 57243, 57260, 57282, D03D 300
Patent
active
055343341
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to base fabrics for ink ribbons used in impact printers.
BACKGROUND ARTS
In recent years, the conventional spool type ink ribbons used in impact printers are being increasingly substituted by cassette type ink ribbons. A cassette type ink ribbon is folded to be contained in the narrow space of a cassette. When the cassette type ink ribbon is used for printing by a printer, the characters printed at the folds become disadvantageously darker than those printed at the other portions of the ink ribbon. The more darkly printed spots are called graphic spots. In recent years, new types of printers quite free from the graphic spots such as laser printers, heat transfer printers and ink jet printers are being marketed, and in this connection, there is an increasing demand for base fabrics for ink ribbons not allowing the graphic spots to occur. To meet the demand, a technique for lessening the graphic spots by disordering the array of monofilaments by high pressure fluid treatment to enhance the ink absorbability is proposed in Japanese Patent Laid-Open No. 91-281277, and techniques for lessening the graphic spots by specifying the weave are proposed in Japanese Patent Laid-Open Nos. 91-34883 and 91-73378.
However, the high pressure fluid treatment proposed as a means for enhancing the ink absorbability of the base fabric requires expensive and additional equipment investment and increases the number of production steps, to considerably raise the cost. The techniques for specifying the weave of the base fabric cannot be said to be satisfactory in the effect to lessen the graphic spot's, and since the weave is loose, the fabric is liable to be caught by the head pins of a serial dot printer as a problem in view of practical use.
DISCLOSURE OF THE INVENTION
The object of the present invention is to present base fabrics for ink ribbons not allowing the graphic spots to occur. To achieve the object, the present invention adopts the following means.
The base fabrics for ink ribbons of the present invention are woven fabrics composed of synthetic multi-filament yarns, comprising the warp used for forming the woven fabrics, being 30 to 50 D (deniers) in yarn thickness and 330 T/M to 600 T/M in the number of twist.
The present invention presents ink ribbons with an excellent property of not allowing the graphic spots to occur, by specifying the number of twist of the warp used for forming the base fabrics.
In addition to not allowing the graphic spots to occur, the base fabrics for ink ribbons of the present invention can well catch the ink and are good in ink permeability, since the yarn surfaces are made more rugged by keeping the number of twist in said range.
The inventors also examined the relation between the number of twist of weft and the graphic spots, and found that the number of twist of weft is irrelevant to the graphic spots. The weft used for forming the woven base fabric for ink ribbons of the present invention can be of any number of twist, and can be even without twist.
In the present invention, the larger the number of twist of warp, the less outstanding the graphic spots. The number of twist of warp in the present invention should be in a range from 330 T/M to 600 T/M, preferably 350 T/M to 500 T/M. If it is less than 330 T/M, the effect of lessening the graphic spots is inssuficient, and if more than 600 T/M, the graphic spots are not lessened relatively to the cost hike.
In general, the yarns used as the warp and the multi-filament yarns used as the weft to form a woven base fabric for ink ribbons are additionally twisted. The twisting machine used is generally a double twister, but the present invention is not limited thereto or thereby.
The twisting speed of the twisting machine depends on the speed of the spindle of the twisting machine, but is usually recommended to be 9000 to 10000 rpm, and the ballooning tension in this case should be preferably 0.4 to 0.5 g/d. But the present invention is not limited thereto or thereby.
The synthetic filament
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patent: 5173360 (1992-12-01), Hiroe et al.
Hama Kenji
Hiroe Nobutake
Kuroda Junko
Dixon Merrick
Miller Austin R.
Ryan Patrick J.
Toray Industries Inc.
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