JPH01136778A - Ink ribbon with little variation in density and production thereof - Google Patents

Abstract

PURPOSE:To reduce variations in printed density and prevent bleeding or mixing of colors of inks of a multicolor ribbon from occurring, by adhering particulates of at least one of a thermoplastic resin and a wax to the surface of fibers constituting a base fabric, in an ink ribbon comprising the base fabric impregnated with the inks. CONSTITUTION:At least one of a thermoplastic resin powder and a wax powder, having a particle size of 5-100mum, is mixed and dispersed into an ink composition in an amount of 1-10wt.%. The ink thus obtained is infiltrated into a base fabric, followed by heating to a temperature slightly higher than the softening point of the resin and the melting point of the wax. By this, the particles of the resin or the wax are adhered to the surface of fibers constituting the base fabric, thereby enhancing an ink retaining property. After the ink ribbon thus obtained is contained in a cassette, the ink infiltrated in the base fabric hardly migrates even at a bent part of the ribbon, so that printed density is not affected at all even when the bent part is brought to a printing part of a printer. There is no possibility of color mixing due to bleeding of the inks at the boundary of different colors in a multicolor ribbon.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ink ribbon suitable for typewriters and word processor printers, and a six-way manufacturing method thereof.

Ink ribbon is a base fabric made of woven threads such as nylon that is coated with ink and impregnated with ink, and its colors are black, yellow,
There are magenta, cyan, etc., and there are also multicolor ink ribbons with these colors applied to the base fabric. The ink composition impregnated into the base fabric generally includes a coloring material, oil, and optionally (a small amount)
Added wax or oil. To explain in more detail using black as an example, the coloring material used is selected from pigments represented by carbon black, azine dyes, and complementary coloring materials such as methyl violet, trephenylmethane dyes, disazo dyes, and tesantene paints. Next, the oil includes mineral oil, dioctyl phthalate, etc. as a pigment dispersant, and a small amount of the dispersant is added. Fatty acid esters such as oleic acid and fatty acid monoglycerides are used as dye solvents.

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

Ink is made by mixing appropriate amounts of these materials.

Ink ribbons are used in the form of cassette ribbons that are rolled or folded into a cassette case, but the most common is a cassette ribbon.

By the way, in the conventional cassette ink ribbon, the ink is squeezed out from the bent part of the ink ribbon that is bent and filled into the cassette case, and when that part reaches the printing part of the printer, the print density becomes darker. The printed letters and figures had shading and looked bad.

In addition, in multicolor ribbons, there is a problem in that the boundaries between the base fabrics impregnated with inks of different colors bleed into each other over time, resulting in a mixture of colors, which is then printed.

This invention reduces printing shading by attaching resin or wax particles to the surface of the RM coating forming the base fabric to improve ink retention so that the ink impregnated into the base fabric does not move easily. , to provide an ink ribbon in which ink bleed and color mixing of a multicolor ribbon is less likely to occur, and its production involves adding at least one of a thermoplastic resin powder and a wax powder with a particle size of 5 to 100 μm to an ink composition.
The ink is mixed and dispersed at a 1ffi ratio of 1 to 10%, impregnated into a base fabric, and then heated 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 a ribbon base fabric made of 66 nylon. Ink is impregnated between the fibers and in the weave of this base fabric, but due to this fiber shape, when the base fabric is bent, the ink oozes out to the surface, and if you print on that area, a large amount of ink will ooze out. The ink is transferred to the print paper, making the print darker than necessary.

In addition, in multicolored ribbons that are impregnated with different color inks next to each other, the ink moves little by little between the fibers and mixes.
As time passes, the range expands. It is sufficient to prevent this phenomenon of ink movement to an extent that does not impair printing performance.

FIG. 2 is an enlarged photograph showing the fiber shape of the ink ribbon base fabric according to the present invention. As is clear from this photo, it can be seen that fine particles adhere to the surface of the base fabric. With such a structure, the fixed particles prevent the ink from moving, and the increased specific surface area of the base fabric acts on the surface tension of the ink, improving ink retention.

The fixed particles are preferably made of a material that is soft and solid at room temperature and easily welded to the base fabric, and that does not easily dissolve in the ink solvent or dispersion medium.

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 carbana wax.

As a result of researching various methods of providing fixed particles on a base fabric as shown in FIG. 2, we found that a manufacturing method in which the powder is added and dispersed in an ink composition, the base fabric is impregnated with this ink, and then heated is found.
It was discovered that the number of steps is small and particles can be fixed to the fine details of fiber bundles.

More specifically, the particle size of the additive powder is 110
If powder containing powder exceeding 0Lt is used, the powder is likely to fall off while the ribbon is being transferred within the cassette case and during printing. In addition, if a powder whose particle size is smaller than 5 μm is used, there will be less unevenness due to adhering powder, no bridges will form between the fibers of the base fabric, and it will be softened or dissolved by oil, increasing the viscosity of the ink and printing. In addition to shortening the lifespan, the desired effect cannot be obtained. Preferably 5-30μ
It is m.

Next, the amount of the resin powder and wax material added is in the range of 1 to 10% by weight. If it is less than 1%, the above-mentioned unevenness and bridging effect cannot be obtained, while if it exceeds 10%, bridges will develop too much, making it difficult for ink to move, and shortening the printing life.

Next, the temperature at which the ink is impregnated into the base fabric and then heated is a temperature sufficient to adhere to the base fabric fibers, and may be a temperature several degrees Celsius higher than the softening point of the resin powder and the melting point of the wax powder.

For the thermoplastic resin powder described above, the temperature is 110°C to 120°C.
This applies to wax powder in the range of 85°C to 110°C.

If the heating temperature is too high, the resin and wax will become impregnated between the fibers of the base fabric, deteriorating the ink retention ability, and will also dissolve into the ink, increasing the viscosity of the ink and impairing print quality.

Example 66 A two-color ribbon was prepared by impregnating a 40/40 denier nylon base fabric with yellow ink and magenta ink in adjacent strips, and the printing quality with a dot printer and the color mixture between each color strip were observed. .

Conventional ink and inventive ink were prepared for each color.

First, for the conventional ink, an insoluble azo pigment was prepared as a yellow coloring material, a soluble azo pigment was prepared as a magenta coloring material, mineral and α-olefin synthetic oils were 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 and mixed to the dispersion medium.

On the other hand, the ink with the actual flow rate of the present invention has a particle size of 5 to 20 mm in addition to the conventional ink composition. It was obtained by adding and mixing 6% of um Fischle-Tropsch wax powder.

Next, two colors of conventional ink were applied to the base fabric using a roll coater to impregnate it, and a comparative test was conducted. In addition, the two colors' actual flow rate ink was applied to the base fabric using a roll coater, and then heated to 110°C after being impregnated.
The sample was kept in a constant temperature room for 20 minutes, and slowly cooled to room temperature.

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

Then, each cassette ribbon was set in a dot printer, solid printing was performed continuously in both colors at a dot duty of 50%, and uneven printing density was visually observed at a position corresponding to the second rotation of the ribbon. Further, after the ribbon was printed 100 times, the state of color mixing at the boundaries of each color band on the ribbon was observed.

As a result, with the conventional product, areas with high print density occurred intermittently, and the color mixture width after 100 cycles reached 1 to 1.5 mm.
At the actual flow rate of the present invention, there was no shading in print density, and the color mixture width was 0.3 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 multicolor ink ribbon with less printing shading and without color mixing.

Furthermore, according to the manufacturing method of the present invention, an ink ribbon with less uneven printing can be produced at a low cost using i! ! It has effects such as being able to create

[Brief explanation of the drawing]

FIG. 1 is an enlarged photographic diagram showing the fiber shape of a conventional ink ribbon base fabric, and FIG. 2 is an enlarged photographic diagram showing the fiber shape of an ink ribbon base fabric according to the present invention. Patent applicant Hitachi Powder Metallurgy Co., Ltd.

Claims (5)

[Claims] (1) In an ink ribbon whose base fabric is impregnated with ink,
An ink ribbon characterized in that at least one of fine particles of thermoplastic resin and wax is adhered to the fiber surface of the base fabric. (2) The ink ribbon according to claim 1, wherein the thermoplastic resin is at least one of acrylic resin, chlorinated rubber, styrene resin, urethane resin, and ketone resin. (3) The ink ribbon according to claim 1, wherein the wax is at least one of polyethylene wax, Fischer-Tropsch wax, and carbana wax. (4) The ink ribbon according to claim 1, characterized in that the base fabric is impregnated with ink of different colors in strips in the width direction. (5) At least one of a thermoplastic resin powder and a wax powder with a particle size of 5 to 100 μm is added in a weight ratio to an ink whose main components are at least one of pigments and dyes, and oil for dispersing and dissolving these. An ink ribbon characterized by dispersing 1 to 10% to form an ink composition, impregnating a base fabric with the ink composition, and then heat-treating at a temperature slightly higher than the softening point of the thermoplastic resin and the melting point of the wax. manufacturing method.