JPS6133870B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a quick-drying ink for inkjet recording, and more particularly to a quick-drying ink for an inkjet system in which ink is ejected by rapid reduction of the internal volume of an ink chamber.

The object of the present invention is to have the contradictory characteristics that the ink itself does not evaporate and dry (clog) in the ejection nozzle, dries immediately when ink droplets are formed on paper, and does not rub off even when rubbed by hand. Satisfied. Moreover, the goal is to create an ink with excellent water resistance.

Conventionally, inkjet recording inks include:
Generally, a water-soluble dye, a polyhydric alcohol, water, and, if necessary, a surfactant and a fungicide are added. This is due to the fact that the diameter of the ink jet nozzle is as small as 50 to 100 .mu.m, as in an inkjet printer, and clogging of the nozzle is prevented by adding a nonvolatile and highly hygroscopic polyhydric alcohol. Therefore, this is a necessary characteristic for an inkjet printer. The quick-drying properties of printed ink are not satisfied, and in order to satisfy this requirement, the paper quality is limited to paper that bleeds easily.Therefore, consumers are advised not to use paper other than that specified by the manufacturer. Therefore, it has disadvantages such as being difficult to handle and making paper expensive.

Furthermore, since the dye is water-soluble, it has relatively poor water resistance, and tends to cause problems such as printing disappearing when it accidentally comes into contact with water.

The present invention was made to improve these drawbacks, and the ink itself has the contradictory properties of being difficult to clog in the nozzle and drying immediately when the ink is deposited on paper. In addition, water resistance has been improved. That is, it is an oil-soluble dye colorant that hardly dissolves in water, a non-volatile and hygroscopic alcohol amine that can dissolve the dye, and a volatile solvent that is soluble in the dye and alcohol amine. be. To explain further, in the quick-drying ink system of the present invention,
After the volatile solvent evaporates, the alcohol amine penetrates into the fibers and the print does not rub off even when rubbed by hand.
This is thought to be due to the permeability of alcohol amines and volatile solvents into paper due to their surface tension. In addition, volatile solvents tend to evaporate in the injection nozzle, just as they do on paper, but due to the non-volatile nature of alcohol amines, if the dye is added below its saturation solubility in alcohol amines, precipitation of the dye can be prevented. This prevents nozzle clogging due to

To explain the present invention in more detail, the oil-soluble dye used in the present invention can be used as long as it does not change the color tone or form a precipitate when added to other ink components. Specifically, CISolvent Black3, 5, 7, 22 CIAcid Black 123 Orient Oil Black BW, Sumisol Black AR
sol CISolvent Blue2, 11, 25, 36, 73 Diaresin Blue JAH CISolvent Red3, 8, 24, 27, 49, 81, 100 Orient Oil Scarlet#308, etc. These can be used alone or in combination of two or more. be done. The addition amount is suitably 0.1 to 7 weight percent (hereinafter abbreviated as wt%) in consideration of contrast and the ability to prevent dye precipitation due to volatile matter evaporation in the injection nozzle, provided that the amount is within the saturation solubility in alcohol amine.

Next, alcohol amines can be used as long as they are non-volatile and can dissolve the dye; specifically, (mono, di, tri) ethanolamine, ethyl monoethanolamine, n-butylethanolamine,
These include dimethylethanolamine, diethylethanolamine, ethyldiethanolamine, n-butyldiethanolamine, di-n-butylethanolamine, triisopropenolamine, isopropenolamine, and the like. The amount to be added is 5%, taking into consideration prevention of ink evaporation and viscosity within the jet nozzle.
~45 (wt%) is suitable.

Furthermore, as a volatile solvent, it mixes well with alcohol amines. aliphatic lower alcohols such as methanol and ethanol, ketones such as acetone,
Polar solvents such as ethers, chloroform and carbon tetrachloride are suitable.

The present invention will be explained below using examples.

Example 1 CISolvent Black3 2.5 (wt%) Diethanolamine 30 Acetone 67.5 This ink was filled into the head shown in Figure 1 of JP-A-52-74406, and the printing speed was 1000 points/second, the pulse voltage was 70 V, and the nozzle diameter was 50 μm. When jet recording was carried out using this method, black printed matter with good contrast was obtained. This printed material was immersed in water for 10 minutes, but the printed material did not disappear and had good water resistance.

Example 2 CI Solvent Blue36 1 (wt/%) Triethanolamine 13 Ethanol 86 This ink was filled into the head described in Example 1, and jet recording was performed at a printing speed of 800 points/second, a pulse voltage of 100 V, and a nozzle diameter of 100 μm. When this was carried out, good blue printed matter was obtained. This was further recorded for 24 hours, and the quality remained good without changing over time. Furthermore, when the recording was repeated three weeks after the recording was completed, no abnormality such as clogging of the nozzle occurred.

As described above, according to the present invention, the ejection nozzle does not become clogged, and when printed on paper, it dries immediately. Moreover, it is an object of the present invention to provide an inkjet recording ink with excellent water resistance.

Claims (1)

[Claims] 1. A quick-drying ink for inkjet recording, comprising an oil-soluble dye, an alcohol amine, and the remainder a volatile polar solvent.