JPS6086179A - Recording liquid - Google Patents

Abstract

PURPOSE:A recording liquid, containing C.I. Food Black 2 and a red dye assuming black elementary color, having high solubility in a liquid medium and solution stability for a long term without clogging extrusion orifices, and useful for ink jet recording and writing utensils. CONSTITUTION:A recording liquid consisting of a liquid composition containing (A) C.I. Food Black 2 and (B) one or more red dyes, preferably C.I. Acid Red 8, 37, 50, 51, 52, 87, 92, 93, 95, 98, 287, 35, 1, etc. together as a water-soluble dye as a recording agent. Preferably, the mixing weight ratio of the dyes (A) to (B) is (100:1)-(100:30), and the total amount of the dyes (A) and (B) in the recording liquid is 1-10wt%. EFFECT:Improved light resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording liquid suitable for use in an inkjet recording method in which recording is performed by ejecting droplets from an orifice of a recording head or for use in a writing instrument, particularly a recording liquid exhibiting an ideal black color. Regarding liquid.

Various types of inkjet recording methods are being actively researched because they generate less noise and can perform high-speed recording on plain paper without requiring special fixing treatment. The recording liquid used in such inkjet recording methods must have physical properties such as viscosity and surface tension within appropriate ranges, must not clog the fine ejection ports (orifices), and must have clear color tones. Moreover, various properties are required, such as providing a recorded image with a sufficiently high density and not causing changes in physical properties or precipitation of solid content during storage.

In addition to these characteristics, recording can be performed without limiting the type of recording material such as paper, fast fixing speed to recording materials, water resistance, solvent resistance (especially alcohol resistance). ), light fastness, abrasion resistance, and the ability to provide images with excellent resolution.

The recording liquid used in the inkjet recording method is basically composed of a dye as a recording agent and its solvent, so the characteristics of the recording liquid are largely influenced by the inherent properties of the dye. . Therefore, selecting a dye so that the recording liquid has the above-mentioned characteristics Xfi is an extremely important technique in this technical field.

In particular, the solubility of the recording liquid in the liquid medium is important, and it is important to have sufficient solubility in water and in wetting agents, which are generally organic solvents, for good anti-clogging properties and This is the basis for maintaining the dissolution stability of the recording agent.

On the other hand, when printing black using the inkjet recording method, it is necessary to use a recording liquid of the black primary color.
In addition, when reproducing a full-color recorded image, a recording liquid of four primary colors is used, in which a black primary color recording liquid is added to a recording liquid of magenta, yellow, and cyan 7(7)E primary colors, and recording is performed by subtractive color mixing of these four primary color recording liquids. The tone of the image is determined. In this case, in order to obtain a recorded image of the desired hue, it is necessary that the hue of each of these recording liquids exhibits the ideal primary colors of magenta, yellow, or cyan, which are not tinged with other colors. The liquid is also required to be ideal, with no other color tinges.

Therefore, it is an extremely important technique to select a dye as a recording material with due consideration to the color tone exhibited by the black recording liquid.

However, as for the conventionally known black recording liquids, there are almost none that fully satisfy the above-mentioned properties, especially solubility, color tone, and light resistance, and it is difficult to develop a black recording liquid that satisfies these characteristics. It was strongly desired.

An object of the present invention is to provide a recording liquid that has high solubility in liquid medium components or long-term dissolution stability and is less likely to clog an ejection orifice.

Another object of the present invention is to provide a recording liquid that exhibits an ideal black primary color and has excellent light resistance.

The above objects and more are achieved by the present invention as follows.

That is, the recording liquid of the present invention is composed of a liquid composition containing a water-soluble dye as a recording agent, and the dyes include C,1, Food Black 2 and (a) C,1, Acid Red 8.
, C,1, Acid Red 37, C,1, Acid Red 50, C,I, Acid Red 51. C,1, Acid Red 52, C,1, Acid Red 87, C,1
, Acid Red 82, C,1, Acid Red 93,
c, r, acid red 85, G, 1. Acid Red 98. It is characterized in that it is used in combination with one or more selected from the group consisting of C,1, Acid Red 287, C,1, Acid Red 35, and C,1, Acid Red 1.

According to the present invention, the viscosity, surface tension, etc. are within appropriate ranges, the fine orifice is not clogged, a recorded image of sufficiently high density is provided, and physical property values change or solid content precipitation etc. are prevented during storage. It is possible to obtain a recording liquid that can perform recording on various members without limiting the type of recording material, has a high fixing speed, and provides images with excellent water resistance, light resistance, abrasion resistance, and resolution.

The dye used as the main component of the recording material in the present invention, CA
, Food Black 2 has excellent solubility, light resistance, etc.--17,H
Al,,wJ'+-1+-1℃1ejA15-1-+1
Pant-E141uJ'! It is extremely excellent in terms of important properties as a liquid recording agent. However, in terms of color tone, the dye exhibits a slightly neutral black color, so this dye alone is not sufficient as a recording material for the black primary color.

On the other hand, the dyes in group (a) are all red dyes, and are extremely excellent in terms of important properties as a recording agent for a recording liquid used in the above-mentioned inkjet recording method, such as solubility and light resistance. It is.

Therefore, in the present invention, by using C,1, Food Black 2 together with one or more dyes selected from group (a), the slightly bluish color tone exhibited by C,L Food Black 2 can be obtained by (a) ) group of dyes, it exhibits an ideal black primary color and has high solubility and
A recording liquid containing a recording agent excellent in important properties such as dissolution stability and light resistance was obtained.

The total amount of dye in the recording liquid, that is, C, 1, food black 2, and one or more dyes selected from group (a), depends on the type of liquid medium and the characteristics required of the recording liquid. Generally, it is 0.5-20% by weight, preferably 0.5-15% by weight based on the total amount of recording liquid
%, more preferably in the range of 1 to 0%.

Also, at this time, C, 1, food black 2 and (a)
The mixing ratio with one or more dyes selected from the group (a) is determined by the optimum value for each combination of those selections, since the color tone or intensity of the color tone exhibited by the dyes in group (a) differs for each dye. However, the weight mixing ratio of c, r, food black 2 and the dye selected from group (a) is too+ 1~
It is preferable to select from within the range of 100:30.

If the mixing ratio is less than 100:1, the slightly bluish color tone exhibited by C, L Food Black 2 will not be improved sufficiently, and if the mixing ratio exceeds +00:30, the resulting recording liquid will have the opposite effect. It is not a suitable color because it has a reddish black color.

The recording liquid of the present invention contains water as a main liquid medium component, and not only water alone but also preferably a mixture of water and various water-soluble organic solvents is used. Examples of water-soluble organic solvents include 1 to 4 carbon atoms, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, 5ec-butyl alcohol, tert-butyl alcohol, and isobutyl alcohol.
Amides such as dimethylformamide and dimethylacetamide; Ketones or ketone alcohols such as acetone and diacetone alcohol; Ethers such as tetrahydrofuran and dioxane; N-methyl-2-pyrrolidone, 1,3-dimethyl- Nitrogen-containing heterocyclic ketones such as 2-imidazolidinone: Polyalkylene glycols such as polyethylene glycol and polypropylene glycol: ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1.2.6-hexandriol , thiodiglycol, hexylene glycol, diethylene glycol and other alkylene glycols in which the alkylene group has 2 to 6 carbon atoms; glycerin; ethylene glycol methyl ether, diethylene glycol methyl (or ethyl) ether, triethylene glycol monomethyl Examples include lower alkyl ethers of polyhydric alcohols such as (or ethyl) ether.

Among these many water-soluble solvents, diethylene glycol, which is a polyhydric alcohol, and triethylene glycol monomethyl (or ethyl) ether, which is a lower alkyl ether of a polyhydric alcohol, are particularly preferred from the viewpoint of preventing clogging.

The content of the water-soluble organic solvent in the recording liquid is generally in the range of 5 to 95%, preferably 10 to 80%, and more preferably 20 to 50%, based on the total weight of the recording liquid. .

The water content at this time is determined within a wide range depending on the type of the solvent component, its composition, or the desired properties of the recording liquid, but is generally 10 to 90% of the total weight of the recording liquid.
%, preferably 10-70%, more preferably 20-7
The range is 0%.

A recording liquid prepared from such components has its own recording properties (signal response, stability of droplet formation, ejection stability, long-term continuous recording, long-term recording after medical treatment). The recording material has excellent, well-balanced properties such as ejection stability), storage stability, fixing property to recording materials, and light resistance, weather resistance, and water resistance of recorded images. In order to further improve such properties, various conventionally known additives may be further included. For example, viscosity regulators such as polyvinyl alcohol, celluloses, and water-soluble resins; various cationic, anionic, or nonionic surfactants; surface tension regulators such as diethanolamine and triethanolamine; PH regulators using buffers; anti-mold Agents, etc. can be mentioned.

Further, in order to prepare a recording liquid used in an inkjet recording method of a type in which the recording liquid is charged, a resistivity adjuster such as an inorganic salt such as lithium chloride, ammonium chloride, or sodium chloride is added.

Note that when applied to an inkjet system in which recording liquid 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.

The present invention will be explained in more detail by the following examples.

Example 1 A black primary color recording liquid for inkjet recording was prepared according to the following formulation.

(1:, 1. Hood bra, Ri 2 2 Weight parts C, T
, 7 liters / Rad 8 0.2 // Diethylene gelcol 301 / N-methyl-2-pyrrolidone 15 tt ion exchange water (hereinafter abbreviated as water) Total remaining amount 100 Parts by weight - 1 - Each component is The mixture was thoroughly mixed and dissolved in a container, filtered under pressure through a Teflon filter with a pore size of 0.45 mm, and then degassed using a vacuum pump to obtain a recording liquid.

An on-demand recording head that uses this recording liquid to eject the recording liquid using a piezo vibrator (discharge orifice diameter 50 scales, piezo vibrator drive voltage 60 mm, frequency 4K)
Using a recording device having the following properties, ejection stability was investigated. As a result, room temperature (21°C), 5°C140
Good ejection stability was maintained in both continuous ejection and intermittent ejection for 48 hours under each atmosphere at 160° C. (humidity 30%).

On the other hand, the long-term storage stability of the recording liquid was investigated at 0°C and 30°C.
The test was carried out at 160°C for two years each, but no problems such as precipitation of the recording agent or discoloration occurred.

The color tone of the printed matter is clear and exhibits an ideal black color without any other color tones, and even after a 50-hour irradiation test with a Canon fade meter, the printed matter remains legible and has excellent light resistance. was also good.

Example 2 A black primary color recording liquid based on the following formulation was prepared in the same manner as in Example 1.

C, 1, Food Black 2 3 Positive Part C, 1, Asindre Rad 37 0.1 //Diethylene glycol
15 tt l, 3-dimethyl-2-imidasilidinone 15 tt polyethylene glycol (30'0) 15 tt water
53 On the other hand, a yellow primary color recording liquid, a cyan primary color recording liquid, and a magenta primary color recording liquid were prepared based on the same composition as above.

However, among the black primary color recording liquids, C,I is used instead of C,1, Food Black 2 and C,I-Acid Lend 37 in the yellow primary color recording liquid.

, Acid Yellow 23 is C in cyan primary color recording liquid.
3■, Direct Blue 86, and magenta primary color recording liquid, C, R, and Acid Lend 35 were mixed at 2% by weight each.

On-demand type multi-head (discharge orifice diameter 35 tiles, heating resistor resistance value 150Ω, drive voltage 30V, frequency 2KHz)
A color printing test was carried out by supplying the sample to a recording device having the following.

Regarding the discharge stability, stable discharge was maintained in all cases under the same conditions as in Example 1. Furthermore, the obtained images were also full-color images with ideal color tones, and each recording liquid was evaluated to be excellent as a recording liquid for subtractive color mixing. Furthermore, even after the same light control test as in Example 1, the prints were legible.

Examples 3 to 14 Bras were produced in the same manner as in Example 1 except that the dyes and their blending amounts shown in Table 1 were used instead of C, 1, Food Black 2 and C, 1, 7 Thintrend 80. Ink primary color recording liquid was prepared. These recording liquids were evaluated for ejection stability, long-term storage stability, color tone of printed matter, and light resistance in the same manner as in Example 1. All of them were good, and they were excellent as recording liquids for the black primary color. There was found.

Table 1 Procedural Amendment (Voluntary) January 17, 1980 Commissioner of the Patent Office Sir 1. Indication of the case 1988 Patent Application No. 11340?7 2. Recording liquid for the name of the invention 3. Person making the amendment Case and Relationship: Patent applicant: Canon Co., Ltd. 4; Agent address: 1-9-20 Akasaka, Minato-ku, Tokyo; Claims (1) A liquid composition containing a water-soluble dye as a recording agent, and the dye includes C,1, Food Black 2, and 7.
A recording liquid characterized by being used in combination with 'species or more.

3. Detailed Description of the Invention The present invention relates to a recording liquid suitable for use in an inkjet recording method in which recording is performed by ejecting droplets from an orifice of a recording head or a writing instrument, particularly a recording liquid exhibiting an ideal black color. Regarding liquid.

Various types of inkjet recording methods are being actively researched because they generate less noise and can perform high-speed recording on plain paper without requiring any special fixing treatment. The recording liquid used in such inkjet recording methods must have physical properties such as viscosity and surface tension within appropriate ranges, must not clog the fine ejection ports (orifices), and must have clear color tones. Moreover, various properties are required, such as providing a recorded image with a sufficiently high density and not causing changes in physical properties or precipitation of solid content during storage.

In addition to these characteristics, recording can be performed without limiting the type of recording material such as paper, fast fixing speed to recording materials, water resistance, solvent resistance (especially alcohol resistance). ), light fastness, abrasion resistance, and the ability to provide images with excellent resolution.

Since the recording liquid used in the inkjet recording method is basically composed of a dye as a recording agent and its solvent, the characteristics of the recording liquid described above are largely influenced by the inherent properties of the dye. . Therefore, selecting a dye so that the recording liquid has the above-mentioned properties is an extremely important technique in this technical field.

In particular, the solubility of the recording liquid in the liquid medium is important, and it is important to have sufficient solubility in water and in wetting agents, which are generally organic solvents, for good anti-clogging properties and This is the basis for maintaining the dissolution stability of the recording agent.

On the other hand, when printing black using the inksheet recording method, it is necessary to use a recording liquid of the black primary color.
Furthermore, when reproducing a full-color recorded image, a recording liquid of four primary colors is used, which is a recording liquid of the three primary colors of magenta, yellow, and cyan plus a recording liquid of the black primary color, and the color tone of the recorded image is changed by subtractive mixing of these colors. It is determined. In this case, in order to obtain a recorded image of the desired hue, it is necessary that the hue of each of these recording liquids exhibits the ideal primary colors of magenta, yellow, or cyan, which are not tinged with other colors. The liquid is also required to be ideal and not tinged with other colors. Therefore, it is an extremely important technique to select a dye as a recording material with due consideration to the color tone exhibited by the blank recording liquid.

However, with regard to the conventionally known black recording liquids, there are almost none that fully satisfy the above-mentioned characteristics, especially solubility, color tone, and light resistance, and it is difficult to develop a black recording liquid that satisfies these characteristics. It was strongly desired.

An object of the present invention is to provide a recording liquid that has high solubility in liquid medium components or long-term dissolution stability and is less likely to clog an ejection orifice.

Another object of the present invention is to provide a recording liquid that exhibits an ideal black primary color and has excellent light resistance.

The above objects and other objects are achieved by the present invention as follows.

That is, the recording liquid of the present invention is characterized in that it consists of a liquid composition containing a water-soluble dye as a recording agent, and as the dye, C,1, Food Black 2 and one or more red dyes are used in combination. .

According to the present invention, the viscosity, surface tension, etc. are within appropriate ranges, the fine orifice is not clogged, a recorded image of sufficiently high density is provided, and physical property values change or solid content precipitation etc. are prevented during storage. It is possible to obtain a recording liquid that can record on a variety of materials without limiting the type of recording material, has a high fixing speed, and provides images with excellent water resistance, light resistance, abrasion resistance, and resolution. .

The dye used as the main component of the recording material in the present invention, C0
1. Food Black 2 is extremely excellent in terms of important properties as a recording agent of a recording liquid applied to the above-mentioned inkjet recording method, such as solubility and light resistance. However, in terms of color tone, it exhibits a slightly bluish black color, so this dye alone is not sufficient as a recording material for the black primary color.

On the other hand, in the present invention, as another recording agent component, c,
r, Food Black 2 and the red dye used individually have a maximum absorption spectrum in the range of 600 nm to 700 nm, and have a high solubility, light fastness, etc. of the recording liquid used in the above-mentioned inkjet recording method. They are excellent in terms of important properties as agents, and one or more of them are used in combination.

Among such red dyes, preferred dyes include, for example, C,1, Acid Red 8. C, 1, Acid Red 37, G, 1. Acid Red 50, C, 1, Acid Red 51. G.1. acid red 52, C
:, 1. Acid Red 87, C,1, Acid Red 82, C,1, Acid Red 93, C,1, Acid Red 85, C,t, Acid Red 98, C,1, Acid Red 287, C1[, Acid Red 35 ,
C, 1, Ashi Ndre Ndo 1, etc. can be mentioned.

These recording agents in the recording liquid, namely G, 1. The total amount of dye, including Food Black 2 and one or more red dyes, is determined depending on the type of liquid medium, the characteristics required of the recording liquid, etc., but in general, it is determined based on the total amount of recording liquid. 0.5～
The content is 20% by weight, preferably 0.5-15%, more preferably 1-10%.

In addition, the mixing ratio of one or more red dyes to C, 1, and food black 2 at this time is optimal for each combination of these selections, since the color tone or intensity of the red dye differs depending on the individual dye. The value of C,1, is determined.
The weight mixing ratio of Food Black 2 and one or more red dyes is preferably selected from the range of 100:I to 100:30. If the mixing ratio is less than +00:i, the slightly bluish color tone exhibited by C, 1 and Food Blank 2 will not be sufficiently improved;
:' If it exceeds 30, the resulting recording liquid will exhibit a reddish black color, which is not suitable.

The recording liquid of the present invention has water as a main liquid medium component, but not only a water wheel but also a mixture of water and various water-soluble organic solvents are preferably used. Examples of water-soluble organic solvents include methyl alcohol, ethyl alcohol, n-propyl alcohol, inpropyl alcohol, n-butyl alcohol, 5ec-butyl alcohol, tert-butyl alcohol, imbutyl alcohol, and the like having 1 to 4 carbon atoms.
Amides such as dimethylformamide and dimethylacetamide; Ketones or ketone alcohols such as acetone and diacetone alcohol; Ethers such as tetrahydrofuran and dioxane; N-methyl-2-pyrrolidone and 1.3-dume. Nitrogen-containing heterocyclic ketones such as chiru-2-imidasolidinone; polyalkylene glycols such as polyethylene glycol and polypropylene glycol: ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, l, 2,6-hexandriol, thio Alkylene glycols in which the alkylene group has 2 to 6 carbon atoms such as diglycol, hexylene glycol, diethylene glycol; glycerin; ethylene glycol methyl ether, diethylene glycol methyl (or ethyl) ether, triethylene glycol monomethyl (or ethyl) ether and lower alkyl ethers of polyhydric alcohols.

Among these many water-soluble solvents, diethylene glycol, which is a polyhydric alcohol, and triethylene glycol monomethyl (or ethyl) ether, which is a lower alkyl ether of a polyhydric alcohol, are particularly preferred from the viewpoint of preventing clogging.

The content of the water-soluble organic solvent in the recording liquid is generally 5 to 85% by weight, preferably 1% by weight based on the total weight of the recording liquid.
The range is 0 to 80%, more preferably 20 to 50%.

The water content at this time is determined within a wide range depending on the type of solvent component, its composition, or the desired characteristics of the recording liquid, but is generally 10 to 80% of the total weight of the recording liquid.
%, preferably 10-70%, more preferably 20-7
The range is 0%.

A recording liquid prepared from such components has its own recording properties (signal response, droplet formation stability, ejection stability,
The balance between long-term continuous recording performance, ejection stability after long-term recording interruptions), storage stability, fixation to the recording material, and the light resistance, weather resistance, and water resistance of the recorded image is important. It is an excellent product. In order to further improve such properties, various conventionally known additives may be further included. For example, polyvinyl alcohol,
Viscosity regulators such as celluloses and water-soluble resins; Various cationic, anionic or nonionic surfactants; Surface tension regulators such as jetanolamine and triethanolamine; PH regulators using buffers; Anti-mold Agents, etc. can be mentioned.

Further, in order to prepare a recording liquid used in an inkjet recording method of a type in which the recording liquid is charged, a resistivity adjuster such as an inorganic salt such as lithium chloride, ammonium chloride, or sodium chloride is added.

Note that when applied to an inkjet system in which recording liquid 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.

The recording liquid of the present invention prepared in this way has C.
1. The slightly bluish tone exhibited by Food Black 2 is offset by the red dye, creating a recording agent that exhibits the ideal black primary color and is also excellent in important properties such as solubility, dissolution stability, and light resistance. This is a recording liquid containing

The present invention will be explained in more detail by the following examples.

Example 1 A black primary color recording liquid for inkjet recording was prepared according to the following formulation.

C, 1, Foot Black 2 2 Weight Parts C, 1, Acid Red 8 0.2 /1 Diethylene Gelcol 3Q
tt N-Methyl-2-pyrroli 1ζ N 15 tttt Exchanged water (hereinafter abbreviated as water) Total remaining amount 100 parts by weight The above ingredients were thoroughly mixed and dissolved in a container, and the pore size was 0.
．． After pressure filtration with a 45 μs Teflon filter,
A recording liquid was prepared by degassing using a vacuum pump.

Using this recording liquid, an on-demand type I recording head (discharge orifice diameter 50mm, piezoelectric vibrator drive voltage 60V, frequency 4KH) discharges the recording liquid using a piezo vibrator.
The ejection stability was investigated using a recording device having the following. As a result, room temperature (21°C), 5°C1
48 at each atmosphere of 40℃ and 60℃ (humidity 30%)
Good ejection stability was maintained in both continuous ejection and intermittent ejection.

On the other hand, we investigated the long-term storage stability of the recording liquid at 0°C130
The test was carried out at 180°C for two years each, but no problems such as precipitation of the recording agent or discoloration occurred.

The color tone of the printed material is clear and exhibits an ideal black color without any other color tones, and the printed material is fully legible even after a 50-hour irradiation test in a xenon fade meter, and has good light resistance. It was good.

Example 2 A black primary color recording liquid based on the following formulation was prepared in the same manner as in Example 1.

C, 1, Food Black 2 3 Parts by weight C, 1,7 sila t'' L/ Ato 37 G, ltt Diethylene glycol 15/1 1,3-dimethyl-2-imidaturidinone 15 // Polyethylene glycol (300) 1'5 //water
53 tt On the other hand, a yellow primary color recording liquid, a cyan primary color recording liquid, and a magenta primary color recording liquid were prepared based on the same composition as above.

However, among the black primary color recording liquids, C01, Food Black 2 and C,1, and yellow primary color recording liquid C,I were used instead of Acid Red 37.

Acid Yellow 23, cyan primary color recording liquid C1■
, Girect Blue-86, and C in magenta primary color recording liquid.
, 1, and Acid Red 35 were mixed at 2% by weight each.

These recording liquids are applied to the recording liquid in the recording head by applying thermal energy to generate droplets to perform recording. 2KH2
), and a color printing test was conducted. Regarding the discharge stability, under the same conditions as in Example 1,
Stable discharge was maintained in all cases. In addition, the obtained image is also a full-color image with ideal color tone,
It was evaluated that each recording liquid was excellent as a recording liquid for subtractive color mixing. Furthermore, even after the same light control test as in Example 1, the printed matter was still legible.

Examples 3 to 14 Black primary color was prepared in the same manner as in Example 1 except that the dyes and their blending amounts shown in Table 1 were used instead of C,1, Food Black 2 and C,1, Acid Red 8. A recording liquid was prepared. These recording liquids were evaluated for ejection stability, long-term storage stability, color tone of printed matter, and light resistance in the same manner as in Example 1, and all were good, making them excellent as recording liquids for the black primary color. It turned out that there was.

Claims (1)

[Claims] (1) It consists of a liquid composition containing a water-soluble dye as a recording agent, and the dyes include C,1, food black 2, and (
a) C, 1, Ashi Ndred 8, G, 1. Acid Red 37, C, 1, Acid Red 50, C, 1,
Acid Red 51, C,1, Acid Red 52,
C,1, Acid Red 87, C,1, Acid Red 92, C,1, Acin Trend 93, C,1, Acid Red 95. C,1, Acid Red 98, C,1,
Ashintrend 287, C, 1, Ashi, Dore. A recording liquid characterized in that it is used in combination with one selected from the group consisting of Acid Red 35, Acid Red 35, Acid Red 35, Acid Red 35, Acid Red 35, Acid Red 35, Acid Red 1, and Acid Red 1.