JPH10316913A - Hot melt solid ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ink scarcely wetting a nozzle plate and showing stabilized delivery characteristics by specifying its angle of contact with an aramid film at a specified temperature. SOLUTION: The angle of contact of the ink should exceed 11 deg. at an ink temperature of 115 deg.C. The composition is not particularly limited and is exemplified by one comprising an amide resin, a wax, an antioxidant, a colorant, etc. The amide resin is a commercially available one or a combination of at least two such ones. The wax is exemplified by a petroleum, vegetable, animal, synthetic hydrocarbon or polymerized one but is desirably a ketone wax or a monoamide wax. The colorant and the colorant such as a dye or a pigment are also not particularly limited. It is also possible to add an ultraviolet absorber, etc., to the ink. The ink is obtained for example by melting the formulation by heating at 70-250 deg.C, mixing the melt under agitation with a mixer such as a dissolver at 200-10,000 rpm and filtering the obtained composition with e.g. a mesh filter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a hot-melt solid ink used in an ink jet recording system.

[0002]

2. Description of the Related Art As an ink jet recording system, there are, for example, an electric field control system for discharging ink using electrostatic attraction; a drop-on-demand system (pressure pulse system) for discharging ink using vibration pressure of a piezo element. Various methods, such as a thermal ink jet method, in which ink is ejected by utilizing pressure generated by forming and growing bubbles by high heat, and the like, can be used to obtain extremely high-resolution printed images.

In these ink jet recording systems, aqueous inks using water as a main solvent and oil-based inks using an organic solvent as a main solvent are generally used. Printed images obtained using water-based inks generally have poor water resistance, whereas using oil-based inks can provide printed images having excellent water resistance.

However, these water-based inks and oil-based inks are liquid at room temperature. Therefore, when printed on recording paper, bleeding is liable to occur, and sufficient printing density cannot be obtained. In addition, since the liquid is used, a precipitate is easily generated from the ink, which causes the reliability of the ink jet recording system to be greatly reduced.

[0005] In order to improve the drawbacks of these conventional inks which are liquid at room temperature, hot-melt solid inks which are solid at ordinary temperature have been proposed. U.S. Pat. No. 3,653,932 discloses an ink containing a dialkyl sebacate, and U.S. Pat. No. 4,390,369 and JP-A-58-108271 disclose an ink containing a natural wax. And JP-A-59-
JP-A-22973 discloses an ink containing stearic acid, and JP-A-61-83268 discloses an ink or alcohol having 20 to 24 carbon atoms and a ketone having a relatively high melting point. JP-A-62-48774 discloses a thermosetting resin having a high hydroxyl value, a solid organic solvent having a melting point higher than 150 ° C., and a small amount of a dye substance. An ink is disclosed. JP-A-62-112627 discloses a coloring material, a first solvent which is solid at room temperature and liquefies when heated to a temperature higher than room temperature, and a room temperature at which the first solvent is dissolved. JP-A-62-295973 discloses an ink comprising a synthetic wax having a polar group and a dye soluble in the synthetic wax. To do Click is disclosed, in JP-A-2-29471, an ink comprising a ketone and amide waxes and wax and colorant are disclosed.

[0006]

In the ink jet recording system, a printed image is obtained by ejecting hot-melted ink from a large number of nozzles provided in a print head. Because of high wettability to the nozzle plate around the nozzle, it easily adhered to the nozzle plate surface. If the ink adheres to the surface of the nozzle plate, it causes the ejection characteristics of the ink to deteriorate, such as non-ejection, variation in the ejection amount, and variation in the ejection direction.

Japanese Patent Application Laid-Open No. Sho 62-223280 discloses an ink having a stable discharge characteristic, the ink having a contact angle of 47 ° or more with a fluorine film. This is intended to improve the ejection characteristics by stabilizing the shape of the ink meniscus, that is, the shape of the ejection front surface of the ink ejected from the nozzles.
However, this does not consider the adhesion of the ink to the nozzle plate described above, and it cannot be said that sufficient ejection characteristics are exhibited.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to provide a hot-melt solid ink having low wettability to a nozzle plate and exhibiting stable ejection characteristics. is there.

[0009]

The above object can be achieved by a hot-melt solid ink having a contact angle with an aramid film of more than 11 ° at an ink temperature of 115 ° C. Hereinafter, the present invention will be described in detail.

The hot-melt solid ink of the present invention has a contact angle with an aramid film of more than 11 ° at an ink temperature of 115 ° C. If it is 11 ° or less,
The wettability to the nozzle plate is increased, and the ejection characteristics such as non-ejection of the ink, a change in the ejection amount, and a change in the ejection direction occur. The relationship between the contact angle of the hot-melt solid ink with the aramid film and the ejection characteristics of the hot-melt solid ink has been found for the first time by the present inventors, and the present invention has been completed.

The aramid film is not particularly limited, and examples thereof include Aramica (manufactured by Asahi Kasei Kogyo). Since the aramid film is extremely chemically stable, data with high reproducibility can be obtained. Further, the contact angle of the hot-melt solid ink to the aramid film has a clear correlation with the contact angles to various materials conventionally used as a nozzle plate in an ink jet recording system. That is,
If the contact angle of the hot-melt solid ink to the aramid film is in the above range, the wettability of the hot-melt solid ink to the nozzle plate made of various materials can be reliably reduced, and stable ejection characteristics can be exhibited. Becomes possible.

The composition of the hot-melt solid ink of the present invention is not particularly limited as long as the contact angle with the aramid film is within the above range. For example, the composition comprises an amide resin, a wax, an antioxidant, a coloring material and the like. And the like.

The amide resin is not particularly limited.
For example, commercially available products such as Versamide 335, 725 (manufactured by Henkel Hakusui), Tomide 90, 92 (manufactured by Fuji Kasei), Sunmide 550, 55 (manufactured by Sanwa Chemical Industry) can be used. These may be used alone or in combination of two or more. In addition to the amide resin, another resin such as a terpene phenol resin may be used in combination.

The wax is not particularly restricted but includes, for example, petroleum waxes such as paraffin wax and microcrystalline wax; vegetable waxes such as candelilla wax, carnauba wax, rice wax and jojoba solid wax; beeswax, lanolin, Animal waxes such as whale wax; mineral waxes such as montan wax; synthetic hydrocarbons such as Fischer-Tropsch wax and polyethylene wax; hydrogenated waxes such as hydrogenated castor oil and hydrogenated castor oil derivatives; montan wax derivatives; Modified waxes; higher fatty acids such as behenic acid, stearic acid, palmitic acid, myristic acid, and uraric acid; higher alcohols such as stearyl alcohol and behenyl alcohol; 12-hydroxystearic acid, 12-hydric Hydroxystearic acid such as xiestearic acid derivative; amine such as dodecylamine, tetradecylamine, octadecylamine; methyl stearate, octadecyl stearate, glycerin fatty acid ester, sorbitan fatty acid ester, propylene glycol fatty acid ester, ethylene glycol fatty acid ester, poly Esters such as oxyethylene fatty acid esters;
Polymerized waxes such as α-olefin maleic anhydride copolymer wax can be exemplified.

As the wax, ketone wax and monoamide wax are preferably used. The ketone wax is not particularly limited. For example, T-1
Stearones such as (manufactured by Kao Corporation) and laurons such as lauron (manufactured by Kanto Kagaku). These may be used alone or in combination of two or more.

The above monoamide wax is not particularly restricted but includes, for example, lauric amide, stearic amide, stearyl stearic amide, oleic amide, erucamide, ricinoleamide, 12-hydroxystearic amide, special fatty acid amide. , N-substituted fatty acid amides and the like. In particular,
For example, Nikka Amide S, Nikka Amide SE, Slipax O (manufactured by Nippon Kasei Co., Ltd.) and the like can be mentioned.
These may be used alone or in combination of two or more.

The antioxidant is not particularly limited.
For example, Irganox 1010 (manufactured by Ciba-Geigy)
And the like.

The coloring material is not particularly limited as long as it is a pigment or dye conventionally used in an oil-based ink composition. The pigment is not particularly limited, and pigments generally used in the technical field of printing, whether organic or inorganic, can be used. Specifically, for example, carbon black, cadmium red, molybdenum red, chrome yellow, cadmium yellow, titanium yellow, chromium oxide, viridian, titanium cobalt green, ultramarine blue, Prussian blue, cobalt blue,
Azo pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, dioxazine pigments, sulene pigments, perylene pigments, perinone pigments, thioindigo pigments, quinophthalone pigments, metal complex pigments, etc. it can. These may be used alone,
Two or more kinds may be used in combination.

The above dye is not particularly limited, and examples thereof include azo dyes, disazo dyes, metal complex dyes, naphthol dyes, anthraquinone dyes, indigo dyes, carbonium dyes, quinone imine dyes, cyanine dyes, quinoline dyes, nitro dyes, and nitroso dyes. , Benzoquinone dye,
Examples thereof include oil-soluble dyes such as naphthoquinone dyes, xanthene dyes, phthalocyanine dyes, and metal phthalocyanine dyes. These may be used alone or in combination of two or more. Further, it can be used in combination with the above pigment.

The hot-melt solid ink of the present invention may contain additives generally added to the hot-melt solid ink, such as an ultraviolet absorber. The hot-melt solid ink of the present invention comprises, for example, an amide resin and an appropriately blended wax.
To 250 ° C., preferably 100 to 200 ° C., and melted with a stirrer such as a dissolver.
00 to 10000 rpm, preferably 500 to 500 rpm
It can be obtained by stirring and mixing at 0 rpm, and filtering the obtained ink composition using a mesh filter or the like.

[0021]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 An amide resin (Sunmide 550, manufactured by Sanwa Chemical Industry Co., Ltd.)
Using a terpene phenol resin (Clearon P115, manufactured by Yasuhara Chemical Co., Ltd.), a ketone wax (T-1, manufactured by Kao Corporation), an ester wax, a fatty acid amide wax, and a yellow dye, and using a hot-melt solid ink in the formulation shown in Table 1. Prepared.

The contact angle of the obtained hot-melt solid ink with an aramid film at an ink temperature of 115 ° C. was measured using a contact angle measuring device (ERMA OPTICAL WORLD).
RKS). The results are shown in Table 1.

The obtained hot-melt solid ink was coated on A4 paper 10 using a hot-melt inkjet printer (manufactured by Brother Industries, Ltd.) having 128 nozzles per color.
The sheets were printed solid. The number of non-ejection nozzles was measured by visually checking the streaks generated due to the absence of ink on the printed image. The results are shown in Table 1.

[0025]

[Table 1]

Example 2 An amide resin (Sunmide 550, manufactured by Sanwa Chemical Industry Co., Ltd.)
A hot-melt solid ink was prepared using a terpene phenol resin (Clearon P115, manufactured by Yasuhara Chemical Co., Ltd.), a ketone wax (T-1, manufactured by Kao Corporation), and a fatty acid amide wax according to the formulation shown in Table 2. For the obtained hot-melt solid ink, the contact angle and the number of non-discharge nozzles were measured in the same manner as in Example 1. The results are shown in Table 2.

[0027]

[Table 2]

Comparative Example 1 An amide resin (Sunmide 550, manufactured by Sanwa Chemical Industry Co., Ltd.)
Using a terpene phenol resin (Clearon P115, manufactured by Yasuhara Chemical Co., Ltd.), a ketone wax (T-1, manufactured by Kao Corporation), an ester wax, a fatty acid amide wax, and a cyan dye, a hot-melt solid ink having the composition shown in Table 3 was used. Prepared. For the obtained hot-melt solid ink, the contact angle and the number of non-discharge nozzles were measured in the same manner as in Example 1. The results are shown in Table 3.

[0029]

[Table 3]

Comparative Example 2 Amide resin (Sunmide 550, manufactured by Sanwa Chemical Industry Co., Ltd.)
Using terpene phenol resin (Clearon P115, manufactured by Yasuhara Chemical Co., Ltd.), ketone wax (T-1, manufactured by Kao Corporation), olefin maleic anhydride wax, fatty acid amide wax, and yellow dye, and heat-melted with the composition shown in Table 4. A solid ink was prepared. For the obtained hot-melt solid ink, the contact angle and the number of non-discharge nozzles were measured in the same manner as in Example 1. The results are shown in Table 4.

[0031]

[Table 4]

[0032]

The hot-melt solid ink of the present invention has the above-described structure, and therefore has low wettability to the nozzle plate and hardly adheres to the nozzle plate. Therefore,
Deterioration of ink ejection characteristics such as non-ejection, change in ejection amount, and change in ejection direction does not occur, and a high-quality print image can be stably obtained. Further, since the frequency of cleaning the print head is reduced, the running cost is also advantageous.

Claims (1)

[Claims] 1. A hot-melt solid ink having a contact angle with an aramid film of more than 11 ° at an ink temperature of 115 ° C.