JPH0114955B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a black ink for printing ribbons of dot printers, and provides an ink having a composition that does not abrade dot wires. As the rationalization of administrative departments has progressed in recent years, various terminal devices such as word processors and computers have come into widespread use in addition to the conventional Roman typewriters and Japanese typewriters. By the way, dot printers are commonly used as printing devices for these office machines, but there is a problem in that their printing ribbons use essentially the same type of ink as that used in conventional typewriters. Now, let's talk about the composition of normal ink.
A coloring material that produces the desired color tone is dispersed in a suitable vehicle, and in the case of the most common black ink, pigments mainly composed of carbon black and nigrosine-based and other dyes are used as coloring materials. It is being By the way, while dye-based coloring materials have the advantage of producing subtle tones, they also have the disadvantage of being easily faded and not suitable for long-term archival documents. The problem is that pigment-based colorants are essentially solid particles that wear out the printer's dot wire. Traditional typewriters used type, and because the type hit the ribbon at a slow speed, wear was not a problem. However, in the case of dot printers, the diameter of the dot wire is as small as 0.3 mm, and the striking speed and printing speed of the wire are incomparably faster than that of a typewriter, resulting in a new problem of wear at the tip of the wire. This is why this occurred. In view of the above-mentioned circumstances, the inventor of the present invention has conducted various studies on the composition of ink, and has decided to add at least one of graphite, molybdenum disulfide, and carbon fluoride, which are known as solid lubricants, to the vehicle. Therefore, quality characteristics such as print clarity and print life remain at the same level as before.
Moreover, they succeeded in developing an ink that reduces the wear of dot wires. Hereinafter, this invention will be explained in detail with reference to examples thereof. First, as an example of conventional ink, Sample 1 using only a pigment-based coloring material and Sample 2 using a mixture of pigment-based and dye-based coloring materials were mixed to the composition shown in Table 1. Two types of printing ribbons were created by applying a 15 m long nylon base fabric to an endless ribbon joined in a Möbius ring shape. Next, Samples 3 to 5 in Table 1 are examples of the present invention, and differ from conventional inks in that they contain an anti-friction material. That is, sample 3 uses graphite as an anti-friction agent in an ink mainly containing pigment-based colorants, sample 4 uses graphite and molybdenum disulfide in an ink mainly containing dye-based pigments, and sample 5 also uses dye-based pigments. Graphite, molybdenum disulfide, and carbon fluoride are added to the ink, which is mainly composed of While the content of the coloring material gradually decreases from sample 3 to sample 5, the amount of graphite in the anti-friction material gradually increases, and the total composition of the coloring material and graphite remains the same throughout each sample. ing. This is because, among the anti-friction materials listed above, only graphite can substitute for black pigment to some extent. Others are dark gray or white in color and cannot be expected to have any effect other than reducing friction. These inks were also prepared on printing ribbons in the same manner as described above, and a total of five types were subjected to printing tests. The printing life of the ribbon in the printing test item is expressed as the number of characters printed while the density of the print decreases to 0.5 in PCS value after installing a new ribbon and starting continuous printing. This is why the ribbon has a long life. By the way, the PCS value is 0 for pure white,
This is an index that expresses density, with pure black being 1.0, and the density of the new ribbon corresponds to 0.9 to 0.8. Note that an A filter is used to measure the PCS value. According to the results of the printing test shown in Table 1, Sample 1, which contained the most pigment-based coloring material, especially carbon black, caused the greatest wire wear and had a slightly inferior printing life compared to Sample 2. Sample 2 also has a long print life because it contains a large amount of dye-based coloring materials, but it suffers from fading easily, and although wire wear has been reduced by half compared to sample 1, it needs to be further reduced. On the other hand, in Samples 3 to 5 according to the present invention, as the added anti-friction material increases and the amount of coloring material, especially pigment, is reduced, the printing life is slightly shortened, but more than that, the wear of the wire is significantly reduced. are doing. Therefore, to describe the characteristics of each sample, the composition of sample 4 contains a large amount of dye-based coloring material, so it is not suitable for documents that will be stored for a long time, but for other uses, it is an ink with a suitable balance between print life and wire life. It is. In addition, the composition of sample 3 has less dye-based coloring material, so it can be used for important documents, and the printing life is the same as that of conventional pigment-based ink (sample 1), and wire wear is less than that of dye-based sample 2. Furthermore, it is only half, etc.
It is judged to be the best overall.

【table】

[Table] Molybdenum disulfide is the most effective anti-friction material, followed by graphite and carbon fluoride, but there is no big difference between them. Further, regarding the amount of addition, it is desirable to set the lower limit to 2%, since wire abrasion is 25 μ when graphite is 2% in sample 3. As described in detail above, according to the present invention, it is possible to provide an excellent printing ribbon whose printing life is comparable to that of conventional ribbons and whose printer head (dot wire) is significantly less worn.

Claims (1)

[Claims] 1. Ink for printing ribbons, which is made by dispersing a coloring material that exhibits a desired color tone in a suitable vehicle,
Graphite, molybdenum disulfide as anti-friction materials,
A black ink for a printing ribbon for a dot printer, characterized in that at least one type of carbon fluoride is added to a vehicle.