JPH0832477B2 - Ink ribbon with little print density and method for producing the same - Google Patents

Description

The present invention relates to an ink ribbon suitable for typewriters and word processor printers, and a method for manufacturing the same.

Ink ribbons are those in which ink is applied and impregnated on a base cloth woven from nylon or the like, and the colors are black, yellow, magenta, cyan, etc. is there. The ink composition with which the base cloth is impregnated is generally one in which a coloring material, an oil and, if necessary, a (trace amount) wax or fat are added. Explaining in more detail using black as an example, the coloring material is selected from pigments such as carbon black and azine-based dyes, and as complementary coloring materials selected from methyl violet, trephenylmethane-based dyes, disazo dyes, thesanthene paints and the like. Next, the oil includes mineral oil, dioctyl phthalate and the like as a dispersant for the pigment, and a trace amount of the dispersant is added. As the solvent for the dye, fatty acid ester such as oleic acid and fatty acid monoglyceride is used.

Further, a small amount of lanolin or polyethylene wax may be used to adjust the fluidity of the ink.

An ink is obtained by mixing these materials in appropriate amounts.

The ink ribbon is used in the form of a cassette ribbon wound in a roll or folded and packed in a cassette case, the latter being common.

By the way, in the conventional cassette ink ribbon, the bent portion of the ink ribbon that is folded and filled in the cassette case is in a state where the ink is squeezed out, and when that portion comes to the printing portion of the printer, the print density becomes dark,
The letters and figures that were punched out had shades and looked bad.

Further, in the multicolor ribbon, there is a problem in that the borders in which the inks of different colors are impregnated into the base fabric are bleeding into each other as time passes and the colors are mixed with each other to be printed.

In order to prevent the ink impregnated into the base cloth from easily moving, the resin or wax particles are adhered to the surface of the fiber forming the base cloth to improve the ink holding property, thereby reducing the print density. The present invention provides an ink ribbon in which multicolor ribbon ink bleeding and color mixing does not easily occur. The production of the ink ribbon includes at least one kind of thermoplastic resin powder having a particle size of 5 to 100 μm and wax powder in a weight ratio of 1 to 1. This is characterized by mixing and dispersing 10%, impregnating the base cloth with this ink, and then heating at a temperature slightly higher than the softening point of the thermoplastic resin and the melting point of the wax.

FIG. 1 is an enlarged photograph showing the fiber shape of the base fabric for a ribbon made of 66 nylon. Ink is impregnated between the fibers of the base cloth and in the weave portion. With such a fiber shape, when the base cloth is bent, the ink oozes out on the surface, and if printing is done in that area, a large amount of ink will be produced. The ink is transferred to the print paper and the print becomes darker than necessary.

Further, in a multicolor ribbon in which different color inks are impregnated adjacent to each other, the inks gradually move between the fibers and are mixed with each other, and the width thereof spreads over time. The phenomenon in which the ink moves in this way may be prevented to the extent that the printing performance is not impaired.

FIG. 2 is an enlarged photograph showing the fiber shape of the ink ribbon base fabric according to the present invention. As you can see from this picture,
It can be seen that fine particles adhere to the surface of the base cloth.
With such a configuration, the fixed particles prevent the ink from moving, and the specific surface area of the base fabric increases, so that the surface tension of the ink acts and the ink holding property is improved.

It is desirable that the adhered particles are soft, solid at room temperature and easily welded to the base cloth, and that they are not easily dissolved in the solvent or dispersion medium of the ink.

Examples of such materials include thermoplastic resins such as acrylic resin, chlorinated rubber, styrene resin, urethane resin and ketone resin, and waxes such as polyethylene wax, Fischer-Tropsch wax and carnauba wax.

As a result of various studies on a method of providing fixed particles on the base cloth as shown in FIG. 2, the manufacturing method in which the powder is added and dispersed in the ink composition, and the ink is impregnated into the base cloth and then heated is shown as the number of steps. Therefore, it was found that the particles can be fixed to the details of the fiber bundle.

More specifically, the particle size of the additive powder is 100
If powder containing powder exceeding μm is used, the powder is likely to fall off during transfer of the ribbon in the cassette case and during printing. In addition, when a powder mainly having a particle size of less than 5 μm is used, there are few irregularities due to the adhered particles, it does not form a bridge between the fibers of the base cloth, and it is softened or dissolved by oil to increase the ink viscosity and print. The life is short, and the desired effect cannot be obtained. Preferably 5 to 30 μm
Is.

Next, the addition amount of the resin powder and the wax is in the range of 1 to 10% by weight. If it is less than 1%, the above-mentioned unevenness and bridge effect cannot be obtained, while if it exceeds 10%, the bridge is overdeveloped and it becomes difficult to move the ink, and the printing life is shortened.

Next, the temperature at which the base cloth is impregnated with the ink and then heated is a temperature that is sufficient to fix the base cloth fibers, and may be higher than the softening point of the resin powder and the melting point of the wax powder by several degrees centigrade.

The range of 110 ° C. to 120 ° C. for the thermoplastic resin powder and the range of 85 ° C. to 110 ° C. for the wax powder correspond to this.

If the heating temperature is too high, the resin and the wax are impregnated between the base fabric fibers to deteriorate the ink holding ability and dissolve in the ink to increase the viscosity of the ink and deteriorate the printing quality.

Example 66 A 2-color ribbon in which a yellow ink and a magenta ink are side by side impregnated into a 40/40 denier base cloth made of nylon and impregnated in a strip shape is prepared, and the print quality by a dot printer and the color mixing state between the color zones are observed. did.

 For the ink, a conventional product and a product of the present invention were prepared for each color.

First, in the conventional ink, an insoluble azo pigment was prepared as a coloring material for yellow, and a soluble azo pigment was prepared as a coloring material for magenta, and mineral and α-olefin synthetic oil was used as a dispersion medium, and polyethylene wax was used as a dispersant. For each color, 15% of the coloring material and 2% of the dispersant were added to the dispersion medium and mixed.

On the other hand, the ink of the product of the present invention was obtained by adding and mixing 6% of Fischer-Tropsch wax powder having a particle size of 5 to 20 μm in addition to the conventional ink composition.

Next, a conventional test of two colors was applied and impregnated on the base fabric with a roll coater, and a comparative test was conducted. Also, the two-color implementation inks are applied to the base fabric with a roll coater and impregnated at 110 ° C.
The sample was kept in a thermostatic chamber kept at 20 minutes for 20 minutes and gradually cooled to room temperature to obtain a sample.

Each of the two-color ribbons was folded and loaded into a cassette case, and the ribbon ends were joined to form a loop-shaped ordinary cassette ribbon.

Then, each cassette ribbon was set in a dot printer, both colors were continuously printed in solid at a dot duty of 50%, and the uneven print density at the position corresponding to the second week of the ribbon was visually observed. In addition, after printing the ribbon 100 times, the color mixture at each color band boundary of the ribbon was observed.

As a result, in the conventional product, a part with a high print density was intermittently generated, and the color mixture width after 100 laps reached 1 to 1.5 mm. Is also 0.
It was 3 mm or less.

As is clear from the above experimental results, according to the ink ribbon of the present invention, it is possible to obtain a multi-color ink ribbon with little print density and no color mixture.

Further, according to the manufacturing method of the present invention, there is an effect such that an ink ribbon having less printing unevenness can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is an enlarged photograph showing a fiber shape of a conventional ink ribbon base cloth, and FIG. 2 is an enlarged photograph showing a fiber shape of an ink ribbon base cloth according to the present invention.

Claims (5)

[Claims] 1. An ink ribbon comprising a base cloth impregnated with ink, wherein at least one kind of fine thermoplastic resin and wax is attached to the fiber surface of the base cloth. 2. The thermoplastic resin is acrylic resin, chlorinated rubber,
The ink ribbon according to claim 1, which is at least one kind of styrene resin, urethane resin, and ketone resin. 3. The wax according to claim 1, wherein the wax is at least one of polyethylene wax, Fischer-Tropsch wax and carnauba wax.
Ink ribbon according to the item. 4. The ink ribbon according to claim 1, wherein the base cloth is impregnated with ink of different colors in a width direction in a strip shape. 5. At least one of a pigment and a dye, and an ink containing an oil for dispersing and dissolving them as a main component, and at least one of a thermoplastic resin powder having a particle size of 5 to 100 μm and a wax powder are weighted. 1 to 10% in terms of a ratio to form an ink composition, and the ink composition is impregnated into a base fabric, and then heat treated at a temperature slightly higher than the softening point of the thermoplastic resin and the melting point of the wax. Ink ribbon manufacturing method.