JPH03252468A - Ink - Google Patents

Abstract

PURPOSE:To obtain ink having excellent clogging resistance, providing record having excellent printing quality and improved permeability, free from oozing on common paper, containing a water-soluble dye, a water-soluble organic solvent, water and specific two kinds of compounds. CONSTITUTION:The objective ink containing a water-soluble dye, a water-soluble organic solvent, water, a compound (preferably triethylamine or triethanolamine salt of oxalic acid, benzoic acid or sulfamoylbenzoic acid) shown by formula I [R1 is carboxyl or (substituted) aryl; R2 to R4 are alkyl, hydroxyalkyl and one of R2 to R4 may be H] and a compound (e.g. compound shown by formula III) shown by formula II (R1 and R2 are H, alkyl or polyfunctional hydroxyalkyl; R3 is carboxyl, OH, sulfonic acid, alkyl or H).

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to ink used in various recording instruments such as writing instruments and printers, and more specifically, to an ink that has excellent clogging prevention properties and is generally used in offices, etc. The present invention relates to an ink that can perform good recording even on standard paper.

(Prior Art) A wide variety of compositions have been reported for inks for writing instruments (fountain pens, signature pens, water-based ballpoint pens, etc.) and inkjet inks.

In particular, in recent years, various aspects such as composition and physical properties have been developed for ink, especially inkjet ink, for good recording even on plain paper commonly used in offices such as copy paper, report paper, notebooks, and stationery. Detailed research and development has been carried out since then.

For example, ink generally contains high-boiling organic solvents such as glycol to prevent drying and clogging, but when recording with such ink on plain paper with a high degree of size, Because the ink penetrates into the paper and the drying properties of the recorded portion are poor, there are problems with fixation, such as ink getting on your hands when you touch the recorded material, and letters rubbing and staining. Ta.

Therefore, in order to increase the permeability of the ink into the inside of the paper, Japanese Patent Application Laid-Open No. 55-29546 proposes a method of adding a large amount of surfactant to the ink. In this case, depending on the paper, there may be a lot of bleeding (occurring), when filling a writing instrument, ink may drip from the pen tip, and when filling an inkjet head, the ink may bleed due to the structure of the head. Depending on the conditions, there were problems such as ink retreating from the orifice surface and no ejection, or conversely, the entire orifice surface becoming wet and ink not being ejected.

Furthermore, Japanese Patent Application Laid-Open No. 54-104933 and Japanese Patent Publication No. 62
-14189 discloses a method of adding N,N-bis[polyoxyethylene (or propylene)]-]P-toluenesulfonic acid amide to an ink,
Although this method is effective in improving the solubility of dyes, it requires the use of a fairly large amount of organic solvent such as polyhydric alcohol in order to sufficiently prevent clogging. There is a problem that the fixing properties of the paper are poor and stains occur even after a long period of time when it comes into contact with the recording material, so it is necessary to use a surfactant in combination to improve the permeability to the paper. As a result, bleeding occurs and the print quality is not sufficient.

Further, when used for inkjet recording and when ink ejection is interrupted, there is a problem that when water or the like evaporates, the above-mentioned compound retreats from the orifice surface, resulting in poor clogging prevention properties.

In addition to the above, various other improvements have been attempted, but unfortunately no ink has been found that can solve all of the problems of drying performance, printing quality, and clogging.

(Problems to be Solved by the Invention) Therefore, the purpose of the present invention is to prevent clogging of the printer head even when the pen tip of a writing instrument or printer device is temporarily stopped or stopped for a long period of time. It is an object of the present invention to provide an ink which is easily recoverable even in the case of ink and which is capable of forming a high-quality image consisting of round dots with little irregular bleeding even on a recording material.

(Means for solving problems) The above objects are achieved by the present invention as described below.

That is, the present invention provides an ink containing a water-soluble dye, a water-soluble organic solvent, and water containing a compound represented by the following general formula (1) and a compound represented by the following general formula (ff). This is a distinctive ink.

(However, R is a carboxyl group, an aryl group, a hydroxyl group, a carboxyl group, a sulfonic acid group, a sulfamoyl group,
Indicates an aryl group substituted with an amino group or an acetylamino group, R, R, or R4 is an alkyl group or a hydroxyalkyl group, and one of R, R, or R4 is a hydrogen atom. You can. ) (However, R1 or R2 represents a hydrogen atom, an alkyl group, a monovalent or polyvalent hydroxyalkyl group, and R3 represents a carboxyl group, a hydroxyl group, a sulfonic acid group, an alkyl group, or a hydrogen atom.) (Function) This The inventors conducted intensive studies on various ink compositions in order to prevent clogging of nozzles during recording and to obtain high-quality images with less ink bleeding on paper. As a result, the inventors incorporated the following general formula ( By containing the compounds represented by I) and (II) together, the clogging prevention property is improved compared to when each is used alone, and in the event of any chance of volatilization in the ink at the tip of the nozzle of the printer head. It has been found that even when the chemical component completely evaporates, the ink ejection recovery becomes very easy.

This phenomenon occurs when the compound of the general formula (I) and the general formula (
Due to the synergistic effect of the compound with U), dye solubility is improved,
It is presumed that this suppresses the increase in viscosity during ink concentration and further enhances the mitigation of aggregation and precipitation of dye during complete evaporation of liquid components. Due to this effect, the number of clogging recovery operations in the printer system and the amount of ink consumed due to this can be reduced as much as possible, making it possible to use the predetermined amount of ink installed in the printer more efficiently than before. .

In addition, when ink containing compounds represented by the following general formulas (1) and (IT) is ejected as droplets from the nozzle of a printer head, it evaporates and penetrates onto the recording material. Due to rapid changes in ink composition, the general formula (I) and (
It was found that since the compound represented by II) rapidly thickens and crystallizes, the printed dots maintain a round shape with little irregular bleeding.

(Preferred Embodiments) Next, the present invention will be described in more detail by citing preferred embodiments.

The compounds represented by the general formula (1) used in the ink of the present invention include oxalic acid, benzoic acid, methylbenzoic acid, hydroxybenzoic acid, phthalic acid, aminobenzoic acid, acetamidobenzoic acid, and sulfamoylbenzoic acid. Trimethylamine salt, triethylamine salt, triethanolamine salt, diethylamine salt, jetanolamine salt, dipropylamine salt, etc. are used. Among these, triethylamine salts or triethanolamine salts of oxalic acid, benzoic acid, and sulfamoylbenzoic acid are particularly preferred.

Further, particularly preferred specific examples of the compounds represented by the general formula (II) of the present invention are shown below, but the present invention is not limited thereto.

The compounds of general formula (I) and general formula (U) above can be used as a mixture of one or more types, and the compounds of general formula (I) and (I
The mixing ratio (weight) of the compound I) can be used in the range of 9/1 to 1/9.

The amount of the mixture of the two added to the ink varies depending on the dye used and other liquid medium components used together, but the proportion in the ink is preferably 05 to 20% by weight, particularly preferably 1. The desired results can be obtained with a proportion of ~10% by weight.

Furthermore, the dye used in the present invention has a color index (C
Almost all of the water-soluble acid dyes, direct dyes, basic dyes, and reactive dyes described in OLOR 1TVDEX can be used. Furthermore, even if the dye is not listed in the color index, any water-soluble dye can be used.

The amount of these dyes to be used is not particularly limited, but - for boat fishing, it is about 0.1 to 0.1% by weight of the total amount of ink.
A range of 15% is preferred, more preferably 0.1-10%.

Further, the liquid medium used in the present invention may be the same as the liquid medium of conventionally known inks, and includes a mixture of water and a water-soluble organic solvent.

Specific water-soluble organic solvents include amides such as dimethylformamide and dimethylacetamide; ketones or keto alcohols such as acetone and diacetone alcohol;
Ethers such as tetrahydrofuran and dioxane; polyalkylene glycols such as polyethylene glycol and polypropylene glycol; ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexandriol, thiodiglycol, hexylene glycol , alkylene glycols in which the alkylene group has 2 to 6 carbon atoms such as diethylene glycol; glycerin; ethylene glycol monomethyl (or ethyl) ether, diethylene glycol monomethyl (or ethyl) ether, triethylene glycol monomethyl (or ethyl) ether, etc. Lower alkyl ethers of polyhydric alcohols; Lower dialkyl ethers of polyhydric alcohols such as triethylene glycol dimethyl (or ethyl) ether and tetraethylene glycol dimethyl (or ethyl) ether; sulfolane, N-methyl-2-pyrrolidone, 1 .3-dimethyl-2
-imidazolidinone and the like.

The content of the water-soluble organic solvent is 1 to 40% by weight, preferably 3 to 30% by weight.

In particular, the amount of wetting agents such as polyhydric alcohols that are commonly used for the purpose of preventing clogging is determined by the anti-clogging effect of the compounds represented by the following general formulas (I) and (II) used in the present invention. Therefore, there is no need to use large amounts (rather, 40
When it is contained in an amount of more than % by weight, the drying properties and print quality on paper deteriorate.

In addition to the above ingredients, the ink of the present invention may optionally contain a water-soluble organic solvent, a surfactant, a pH adjuster, a rust preventive agent, a preservative, a fungicide, an antioxidant, an evaporation accelerator, and a chelating agent. agent,
Various additives such as water-soluble polymers may be added.

(Example) Next, the present invention will be explained in more detail by giving examples and comparative examples. In the text, parts and percentages are based on weight unless otherwise specified.

Examples 1 to 6 and Comparative Examples 1 to 4 The following components were mixed and sufficiently stirred to dissolve, and then a Fluorobor filter with a pore size of 0.45 μm (manufactured by Sumitomo Electric Industries, Ltd.) was prepared.
6 types of inks of the present invention and 4 types of comparative inks were obtained.

1 Ink C, 1, Direct Black 154 3 parts Glycerin 10 parts Oxalic acid/triethanolamine salt 3 parts Exemplary compound 1 of general formula (It) 2 parts Water
82 parts 12 inks.

C, 1, hood black 2 diethylene glycol isoprobyl alcohol Benzoic acid/triethylamine salt Exemplary compound 2 of general formula (II) water 13 ink.

C, 1, Direct Black 154 Triethylene glycol sulfamoylbenzoic acid 4 parts 7 parts Ethylamine salt 2.5 parts 2.5 parts 84 parts 2 parts 5 parts 3 parts 2 parts 3 parts 85 parts General formula (II ) Exemplary compound 1 Water 4 Ink C, 1, Food black 2 Diethylene glycol benzoic acid triethylamine salt Exemplary compound 3 of general formula (II) 3 parts 10 parts 4 parts 2 parts 81 parts 2 parts 5 parts 4 parts 2 parts 4 parts 83 parts 15 Ink C, 1, Direct Black 154 Glycerin Isopropyl alcohol Oxalic acid/triethanolamine salt Exemplary compound of general formula (IT) 8 Water 16 Ink C, 1, Food Black 2 Triethylene glycol sulfamoyl Benzoic acid 4 parts 10 parts Triethylamine salt 3 parts Exemplary compound 2 of general formula (II) 2 parts Water
81 copies) 1
ink.

C, 1, Direct Black 154 3 parts Glycerin 10 parts Exemplary compound 1 of general formula (H) 2 parts Water
85 parts 12 ink thread C, 1, food black 2 2 parts diethylene glycol 5 parts isopropyl alcohol 3 parts water
90 parts 13 inks.

C, 1, Food Black 2 4 parts Glycerin 10 parts Oleic acid/triethanolamine salt 3 parts Water
83 parts 14 ink composition C, 1, food black 2 3 parts diethylene glycol 10 parts capric acid monoethanolamine salt 5 parts water
82 parts Next, using the obtained inks of Examples 1 to 6 and Comparative Examples 1 to 4, an inkjet printer BJ- was used as an inkjet recording device using a heating element as an ink ejection energy source.
130 (trade name: manufactured by Canon ■), printing drying property evaluation, clogging property evaluation, and printing quality evaluation were performed.

The results are shown in Table 1 below.

[Evaluation method and evaluation criteria] (1) Evaluation of printing dryness Regarding printing dryness, alphanumeric characters were printed on commercially available continuous slip paper using a printer, and then 10.20.30.40.
After 50 and 60 seconds, filter paper [Toyo Roshi Co., Ltd., No. 2]
(Part name)], and the judgment was made based on the number of seconds until the printed area was no longer smudged (measured at 20 parts at 5°C and 50 parts at 10% RH).

○...Within 15 seconds △...16-30 seconds ×...30 seconds or more (2) Clogging property evaluation After filling the printer with the specified ink and printing alphanumeric characters continuously for 10 minutes , stop printing, apply a cap and leave for 30 days (Leaving conditions: 260℃ and 10 parts 5%
RH), a nozzle clogging recovery operation was performed, alphanumeric characters were printed again, and judgment was made based on the number of recovery operations until the initial printing condition could be reproduced.

O...Printing equivalent to initial printing is possible without recovery operations.

O...Printing equivalent to the initial state is possible after 1 to 5 recovery operations.

△...Printing equivalent to the initial state is possible after 6 to 10 recovery operations.

×...Printing equivalent to the initial one is possible after 11 or more recovery operations.

(3) Evaluation of printing quality After printing on commercially available copy paper (XEROX 4024), leave it for more than 1 hour, and then there will be no bleeding at the dot level.
Edge sharpness was evaluated under environmental conditions of 25° C. and 60% RH.

○: There is no bleeding and the edges are sharp.

△: Some bleeding is observed, and the edges are also slightly blurred.

×: There is a lot of bleeding, and dots and edges are blurred.

(Hereinafter referred to as margins) 1 (Effects) As explained above, the ink of the present invention does not bleed even on plain paper commonly used in offices such as copy paper, report paper, notebooks, and stationery. It is possible to obtain records with excellent print quality and good permeability.

Further, according to the present invention, highly reliable recording can be performed without clogging of the pen tip of a writing instrument or the nozzle of an inkjet head.

Claims (1)

[Claims] (1) An ink containing a water-soluble dye, a water-soluble organic solvent, and water, characterized by containing a compound represented by the following general formula (I) and a compound represented by the following general formula (II) ink. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (However, R_1 represents a carboxyl group, an aryl group, or an aryl group substituted with a hydroxyl group, a carboxyl group, a sulfonic acid group, a sulfamoyl group, an amino group, or an acetylamino group. , R_2, R_3 or R_4 is an alkyl group or a hydroxyalkyl group, and R_2, R_3 or R
Any one of _4 may be a hydrogen atom. ) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(III) (However, R_1 or R_2 is a hydrogen atom, an alkyl group, 1
represents a valent or polyvalent hydroxyalkyl group, and R_3 represents a carboxyl group, a hydroxyl group, a sulfonic acid group, an alkyl group, or a hydrogen atom. )