JPS6232159A - Recording fluid and recording method using same - Google Patents

Abstract

PURPOSE:To obtain a recording fluid which is safe, does not cause clogging and has proper ink physical properties and good shelf stability, containing a recording agent and a liquid medium for dissolving or dispersing it as main components and further a diether compd. CONSTITUTION:A recording fluid contains a recording agent and a liquid medi um for dissolving or dispersing it as main components and further a compd. of the formula (wherein R1, R2 are each a 1-6C alkyl, an 8C or lower aryl; n is an integer). Examples of the recording agents are water-soluble dyes such as direct dye, acid dye and food dye; disperse dye and pigment. The recording agent is used in an amount of pref. 0.5-15wt% and the compd. of the formula is used in an amount of pref. 0.5-50wt%. When the recording fluid is sued for printing general-purpose paper such as copying paper, reporting paper or bond paper which are sized and wherein fiber is exposed to the surface to be recorded, printing which as a high fixation rate and is scarcely blotted can be obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a recording liquid and a recording method using the same.
In particular, the present invention relates to a recording liquid that fixes quickly and causes less bleeding, and a recording method using the same, for papers commonly used in offices and homes, such as copy paper, report paper, pound paper, and continuous slip paper.

[Conventional technology]

In the past, many proposals have been made regarding ink for inkjet recording, and among them, inks that mainly contain water or a water-soluble organic solvent to dissolve dyes have been the main ones.

Although the required performance of this type of ink differs slightly depending on the recording method, the commonly required performances are: 1) ink physical properties such as viscosity and surface tension within appropriate ranges; 2) nozzle and ink distribution. 3) The ink should not become clogged in the path, and 3) The ink should not change in any way even after long-term storage.

4) Good quality recorded images can be obtained, 5) Fast fixing speed, 6) Excellent durability of printed matter such as water resistance and light resistance, 7) High safety. etc.

In order to satisfy some or all of the above objectives, studies are still actively being conducted on recording agents, solvents, and various additives (surfactants, chelating agents, antifungal agents, etc.) that make up ink. It is.

However, even if some of the inks that have been crystallized have been investigated, the current situation is that there is still no ink that fully satisfies the above objectives.

For example, if a mixture of dye and water is prepared with polyalkylene gelylcol or glycerin, which is difficult to volatilize to prevent clogging, either alone or in a mixture, the ink will have weak penetrating power on large-sized plain paper. Fixation may take several minutes, which is a problem in practice. There are some proposals to add surfactants to improve this, but
Even if the fixing speed can be improved to a satisfactory degree depending on the type and amount of surfactant added, there is a drawback that bleeding becomes large and the print quality is significantly reduced. In addition, ink containing a strong basic substance instead of a surfactant destroys the internal sizing agent typified by rosin, resulting in faster fixing speed and prints with less bleeding.

However, with acid-free paper, it is almost ineffective due to the difference in sizing agents, and it is dangerous to use at home or in the office because it is a high-pH substance.

In addition, mono- and dialkyl ethers of ethylene glycol and diethylene glycol have been proposed as means for increasing the fixing speed, but they have a high vapor pressure and cause an unpleasant odor. It has also been pointed out that it poses health problems for users. Furthermore, if the alkylene glycol chain is extended to form a monoalkyl ether, the odor problem will be solved by lowering the vapor pressure, but as with surfactants, bleeding will become a problem as the fixing speed increases. .

[Problem that the invention seeks to solve]

The present invention solves all of the above problems.

That is, an object of the present invention is to provide a recording liquid that is safe, does not cause clogging, and has appropriate ink physical properties.

Another object of the present invention is to provide a recording liquid with good storage stability.

Still another object of the present invention is to provide copy paper, report paper,
A recording liquid that provides fast fixing speed and prints with little bleeding when recording on general paper that is sized and has LA fibers exposed on the recording surface, such as pound paper and continuous slip paper. The goal is to provide a recording method.

[Means for solving problems]

The above object is achieved by the present invention as follows.

That is, the present invention provides a recording liquid mainly composed of a recording agent and a liquid medium for dissolving or dispersing the recording agent, which is characterized in that it contains a compound represented by the following general formula [I]. It is.

R1-0-(CH2-CH2-0)-nR2[I] (wherein, 'R1 and R2 are each independently carbon. Furthermore, in the present invention, the recording liquid is sized and coated using the above recording liquid. This is a recording method in which recording is performed on a recording material with fibers exposed on the recording surface.

Two functions] Used in the present invention. Specific examples of compounds represented by the general formula CI) are shown in Table 1.

These compounds are obtained by conventionally known methods, but 3
Above, it is desirable that it is 20 or less. When n is within the above range, the compound of general formula (1) has a low vapor pressure and is difficult to evaporate at around room temperature, so that odor is not bothersome.

Furthermore, the compound of general formula CI) has a higher seedling pressure than the corresponding polyoxyethylene.

Since the viscosity is low and the interfacial tension with paper is also low, it has the effect of increasing the fixing speed of the ink.

On the other hand, in general formula CI), when n is 2 or less, the permeability into paper and the solubility in solvents are relatively good, but the vapor pressure is high and the odor is significant.

Table 1 Also, there is no effect of preventing clogging at the tip of the orifice, and on the contrary, it often accelerates clogging, and there are also problems in terms of occupational health.

On the other hand, when n is 21 or more, there is a problem that the viscosity increases significantly and the fixing speed cannot be improved.

In general formula [I], the longer the carbon chain of the alkyl group, the greater the effect of penetrating into paper. However, it has been found that the number of carbon atoms in the alkyl group decreases rapidly when the number of carbon atoms exceeds 7.

Therefore, the alkyl group preferably has 1 to 6 carbon atoms.

In addition, it is preferable that the number of carbon atoms in the compound as a whole is 9 or more.The content of these compounds is limited due to the balance between the fixing time and bleeding of the ink, but by changing the length of n, the total amount of the ink can be increased. The viscosity can be adjusted.

Since the compound of general formula CI) is a diether, its surface activation ability is milder than that of monoethers, and it is thought that the printed matter is less likely to bleed.

Further, since the above compound is a polymer whose main chain is only ethylene oxide, it has better compatibility with water than random and block polymers containing both ethylene oxide and propylene oxide.

The content of the compound represented by the general formula CI) in the total amount of the ink is preferably 0.5 to 50% by weight.

When the content is less than 0.5% by weight, little effect of ink penetration into paper can be expected, and when the content exceeds 50% by weight, bleeding becomes noticeable and the ink is not compatible with water. Deteriorate.

When the compound represented by the general formula CI) is used together with water or a mixed system of water and a water-soluble organic solvent, favorable results can be obtained in terms of fixing speed on recording materials, printing quality, etc.

Examples of suitable water-soluble organic solvents used in combination here include:
Charcoal 1-4 alkyl alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, SeC-butyl alcohol, tert-butyl alcohol, and inbutyl alcohol; Amides such as dimethylformamide and dimethylacetamide Types: Ketones or ketone 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, I-diethylene glycol, 1, 2. Alkylene glycols in which the alkylene group contains 2 to 6 carbon atoms, such as 6-hexa/triol, thiodiglycol, hequinlene glycols, diethylene glycol: glycerin; N-methyl-2-pyrrolidone, 1,3- Examples include dimethyl-2-imidazolidinone, triethanolamine, and sulfolane.

The content of these water-soluble organic solvents is generally desirably within the range of 2 to 70%, preferably 5 to 65%, more preferably 10 to 60% by weight.

The water content is preferably in the range of 20 to 85% by weight.

Examples of the recording agent used in the recording liquid of the present invention include direct dyes, acid dyes, water-soluble dyes such as food dyes, disperse dyes, and pigments.

Among these, water-soluble dyes are preferred from the viewpoint of various properties.

The content of these recording agents is determined depending on the type of liquid medium components, the characteristics required of the ink, etc., but is generally 0.5 to 20%, preferably 0.5 to 20%, based on the total weight of the ink.
15%, more preferably in the range of 1 to 10%.

The essential components of the ink composition of the present invention are as described above, but various other conventionally known dispersants and surfactants can be added as necessary.

Dispersants or surfactants that may be added as necessary include fatty acid salts, alkyl sulfate ester salts, alkylbenzene sulfonates, alkylnaphthalene sulfonates, dialkyl sulfosuccinic acid groups, alkyl phosphate ester salts, naphthalene sulfonate formalin. Anionic dispersants or surfactants such as condensates, phosphoryoxyethylene alkyl sulfate salts; polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters , polyoxyethylene alkylamine.

Nonionic dispersants or surfactants such as glycerin fatty acid esters and oxyethylene oxypcobylene block copolymers are important.

As mentioned above, the addition of a surfactant has a very large effect on bleeding, so it is generally added to 0.00% of the total weight of the ink.
3% or less, preferably 0.2% or less, more preferably 0
．． It is necessary to keep it below 1%.

Furthermore, in order to prepare inks used in inkjet recording methods that charge the ink, resistivity adjusters such as lithium chloride, ammonium chloride, and inorganic salts of sodium chloride are added.

Note that when applied to an inkjet system in which ink is ejected by the action of thermal energy, thermal physical property values (eg, specific heat, coefficient of thermal expansion, thermal conductivity, etc.) may be adjusted.

In addition, additives other than the above three types may be used as necessary.
For example, antifoaming agents, antifungal agents, pH adjusters, etc. can be added as appropriate.

As described above, the present invention focuses on the ether-linked derivatives of alkylene glycol polymers and oligomers in the water-soluble organic solvents contained, and describes the type of alkylene glycol, the number of additions, and the functionality to be reacted at the terminal. This was arrived at as a result of systematic research on the base.

That is, the recording liquid of the present invention can be used without impairing the properties required for inkjet inks, etc., and can be applied to fP) plain paper, that is, a recording material that is sized and has fibers exposed on the recording surface, specifically [Example] The present invention will be explained in more detail with reference to an example. do. still,
In the text, parts and percentages are based on weight.

Example 1 The above components were placed in a container, stirred for 5 hours, and adjusted to pH 7.5 with a 1% aqueous sodium hydroxide solution.

Next, pressure filtration was performed using a fluorobore filter (trade name; manufactured by Sumitomo Electric Industries, Ltd.) with a pore size of 0.45 gm to obtain recording liquid A of the present invention. The physical properties, solubility, and odor of the obtained recording liquid A were evaluated. The results are shown in Table 2.

Next, the above-mentioned recording liquid A was loaded onto an inkjet printer (prototype experimental machine, manufactured by Canon Inc.) that performs recording using thermal energy, and printed on continuous slip paper or copy paper to check the fixing properties. The recording characteristics of bleeding were evaluated.

Furthermore, the print head was left for 5 minutes without capping, and the printing operation was performed again.

After printing 3 lines, turn off the printer,
Experimental Examples 2 to 6 to check the clogging status of the nozzle of the 24 wood Recording liquid B Recording liquid C Recording liquid D Recording liquid E Recording liquid F In Example 1, the above recording liquids B-F were used instead of recording liquid A. The evaluation of each recording liquid and the recording characteristics were carried out in exactly the same manner as in Example 1, except that the recording liquids were used. The results are shown in Tables 2 and 3.

Table 2 01 Evaluation Criteria O: Ink is completely homogenized ×: Separation of oily substance is observed.

×: The level of discomfort felt in the office or home.

Table 3 1″3 Ten and 30 seconds after printing, the printed area was rubbed against filter paper (trade name: No. 5C, manufactured by Toyo Kagaku Sangyo (■)) with lens cleaning paper.

0... Fading in 10 seconds None 0... Fading in 10 seconds Small Δ... Fading in 30 seconds Small x... Fading in 30 seconds Large x 4 Printing Drum) Number of dots with blur out of 300 was evaluated as a percentage.

Q: Bleeding is less than 10% Δ... Bleeding is 105 to less than 1205 ×... Bleeding is 20% or more '5 24 Number of wood nozzles that were clogged.

It should be noted that the clogging of the inks (C) and (D) of Examples was eliminated by performing a recovery operation. [Effects] The effects of the present invention are summarized below. (1) Ink physical property values are within appropriate ranges and stable ejection can be obtained; (2) Nozzle clogging due to ink does not occur.

(3) Less bleeding of printed matter and faster fixing speed (4)
The ink has no odor, (5) the ink has excellent dissolution stability, (6) plain paper used in offices and homes, i.e. copy paper,
It is possible to record on pound paper, report paper, and continuous slip paper.

Claims (3)

[Claims] (1) In a recording liquid mainly composed of a recording agent and a liquid medium for dissolving or dispersing it, the general formula [I] R_1-O-(CH_2-CH_2-O)-_nR_2
[I] (In the formula, R_1 and R_2 each independently represent an alkyl group having 1 to 6 carbon atoms or an aryl group having 8 or less carbon atoms. n is a positive integer.) A recording liquid characterized by containing a compound. (2) The recording liquid according to claim 1, which contains the compound in an amount of 0.5 to 50% by weight based on the total weight of the recording liquid. (3) In a recording method in which recording is performed by forming droplets of a recording liquid and adhering the droplets to a recording material, the recording liquid has the general formula [I], R_1-O-(CH_2 -CH_2-O)-_nR_2
[I] (However, in the formula, R_1 and R_2 each independently contain a compound represented by the number of carbon atoms, and the recording material is sized and the fibers are exposed on the recording surface. A recording method characterized by.