JP3244754B2 - Azo compound, ink containing the same, and recording method using the ink - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel azo compound, an ink containing the azo compound as a recording agent, an ink-jet recording method using the ink, and a device using the ink. Paper,
Suitable for inks with high print density and improved water resistance on uncoated paper, so-called plain paper, such as bond paper and report paper, and a recording material whose surface has an ink receiving layer consisting of a binder and a pigment. The present invention relates to a novel azo compound suitable for an ink having improved indoor discoloration of an image recorded on paper, so-called coated paper, an ink containing the compound, and an ink jet recording method using the ink.

[0002]

2. Description of the Related Art Conventionally, an aqueous ink obtained by dissolving a water-soluble dye in an aqueous medium has been used as an ink for ink jet recording. In these conventional inks,
(1) To give an image with a sufficient density, (2) Good dryness on the recording material, (3) Less bleeding in the recorded image, (4) Even when contacting with water, alcohol, etc. That the recorded image does not flow out or is sufficiently legible even if it flows out (water resistance); (5) the light resistance of the recorded image is excellent; (6) clogging does not occur at the pen tip or nozzle tip; (7) No inconvenience such as blurring of the recorded image occurs at the time of continuous recording or at the start of recording after being left for a long time (ejection stability); (8) The ink is stable during storage; ) In use, it is required that no problem occurs even if it comes into contact with the members constituting the recording means, and (10) there is no problem in the safety of the user. In addition to the above requirements, (11) excellent heat resistance And it does not adversely affect the thermal energy generating means, is required.

[0003] These properties depend not only on the composition of the ink, but also on the properties of the dye contained as a recording agent. It is not easy to meet all of the above performance requirements using existing dyes.

Examples of specific dyes include, for example, C.I. in both the mono-color and full-color images in the field of ink jet recording. I. Food Black 2 has been mainly used (JP-A-59-93766 and JP-A-59-93766).
-93768).

C. I. The ink using Food Black 2 is excellent in that it provides an image with a sufficient density, but has problems in light resistance and water resistance. That is, if the printed matter is exposed to room light for a long time or is posted near a copying machine, the black color changes to brown and the image quality is significantly reduced. Especially severe). In addition, there is a problem that it is difficult to read when a test is performed on the assumption that water has been spilled on an image.

JP-A-55-140467 and JP-A-61-285276 disclose inks having improved storage stability and ejection responsiveness by specifying a dye structure. Is not yet water-resistant.
Furthermore, the former ink does not solve the above-mentioned problem of discoloration.

JP-A-1-135880 discloses an ink in which ejection stability, water resistance of an image, and the like are improved by introducing at least one specific structural unit into a dye structure. Furthermore, Japanese Patent Application Laid-Open No. 1-193375 discloses a black ink which has a high affinity for a recording material, has excellent fixability and water resistance, and gives good print quality to plain paper. Tokiko 62-102
No. 74 discloses an ink in consideration of ejection stability, light fastness of an image, and the like. JP-A-3-781 and JP-A-3-782 disclose inks that are hardly clogged and have little discoloration. JP-A-3-294366
And JP-A-3-294367 disclose an ink with less discoloration.

[0008] First, the ink must have a performance suitable for the recording system.
In addition, it is required to exhibit sufficient performance as a printed matter, that is, in terms of quality and robustness. However,
Satisfying all of the various required performances is considerably difficult as seen in the above-mentioned known examples.

[0009] The discoloration problem has been attracting attention as a result of solving many problems by the advancement of technology, which was not so much a problem in the past.
In particular, the effect is significant for a large amount of black ink, and in the case of a full-color image, the discoloration causes a sharp decrease in image quality.

[0010] The problem of discoloration progresses even in a room where direct sunlight is not applied, and also depends on the type of recording material for forming an image, and is remarkable in paper containing a pigment such as silica. Conventionally used C.I. I. Food Black 2 did not solve this problem.

By selecting a dye having good light fastness, C.I. I. Attempts have been made to solve the disadvantages of Food Black 2, and satisfactory results have been obtained with plain paper. However, in the case of a so-called coated paper in which an ink receiving layer containing a pigment and a binder is formed on a base material such as paper in order to improve image quality such as color development, clarity, and resolution of the dye, it is common. Even if the ink has little problem on paper, remarkable discoloration occurs, and the problem cannot be solved simply by selecting a dye having good light fastness.

In addition, as a compound similar to the compound of the present invention, JP-A-55-152747 discloses a compound for dyeing a cellulosic fiber material, paper or leather in black.

[0013]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a recording medium containing, when contained in an ink, a high image density and a clear image density on various types of plain paper.
Suitable for inks with excellent quality, excellent fixability, no clogging, excellent storage stability, thermal stability and safety. Another object of the present invention is to provide a novel azo compound, an ink containing the compound, and an ink jet recording method using the ink. A second object of the present invention is to provide a novel azo compound which is suitable for an ink with little discoloration of an image even when printed on coated paper.

[0014]

The above object is achieved by the present invention described below. That is, the present invention is an azo compound represented by the following general formula (A).

[0015]

[Outside 13] (However, R ₁ , R ₂ or R ₃ each represents a hydrogen atom and a carbon number of 1 to
Alkyl group, methoxy group, halogen atom, COO
M, represents a group selected from the group consisting of COOR _4, wherein R ₄ represents an alkyl group having 1 to 4 carbon atoms, M represents an alkali metal or an ammonium or organic ammonium. )

The present invention is a black dye composition containing an azo compound represented by the following general formula (A) as a main component.

[0017]

[Outside 14] (However, R ₁ , R ₂ or R ₃ each represents a hydrogen atom and a carbon number of 1 to
Alkyl group, methoxy group, halogen atom, COO
M, represents a group selected from the group consisting of COOR _4, wherein R ₄ represents an alkyl group having 1 to 4 carbon atoms, M represents an alkali metal or an ammonium or organic ammonium. )

The present invention provides an ink containing a recording agent and a liquid medium in which the recording agent is dissolved or dispersed, wherein the recording agent contains a novel azo compound represented by the following general formula (A). This is an inkjet recording method using ink.

[0019]

[Outside 15] (However, R ₁ , R ₂ or R ₃ each represents a hydrogen atom and a carbon number of 1 to
Alkyl group, methoxy group, halogen atom, COO
M, represents a group selected from the group consisting of COOR _4, wherein R ₄ represents an alkyl group having 1 to 4 carbon atoms, M represents an alkali metal or an ammonium or organic ammonium. )

[0020]

According to the present invention, by containing the compound of the general formula (A) as a recording agent for an ink, not only the density of the recorded image is high when recorded on plain paper, but also the water resistance is excellent. In addition, there is provided an ink which gives a black image with little discoloration even when recorded on coated paper, and an ink jet recording method using the same.

(Preferred Embodiment) Next, the present invention will be described in more detail with reference to preferred embodiments.

Preferred specific examples of the azo compound (dye) represented by the general formula (A) which mainly characterizes the present invention include the following compounds (dyes) (M is an alkali metal or ammonium or an organic compound). Represents ammonium).

[0023]

[Outside 16]

[0024]

[Outside 17]

[0025]

[Outside 18]

Among these, more preferred specific examples include the following compounds.

[0027]

[Outside 19]

[0028]

[Outside 20]

[0029]

[Outside 21]

The azo compound (dye) of the present invention is generally a sodium salt of a water-soluble group such as a sulfonic acid group, but the present invention is not limited to these sodium salts.
The same effect is obtained even if those counter ions are potassium, lithium, ammonia, organic amines and the like, and the present invention also includes dyes containing these other counter ions. And the dye of this invention can be used as a favorable black pigment.

The production of the above dye is described in "Theoretical Production" by Yutaka Hosoda
It is synthesized as follows according to the method described in "Dye Chemistry".

Synthesis Example Specific Example No. Dye No. 3 is synthesized as follows. m-
Chloroaniline is diazotized according to a conventional method, coupled with 2,5-dimethoxyaniline, and the resulting monoazo compound is separated. This is diazotized, alkaline and coupled with gamma acid to separate the disazo form. Further, this is diazotized, coupled with m-phenylenediamine-4-sulfonic acid, salted out with sodium acetate, washed with ethanol and purified to obtain a desired dye. The dye of the present invention can be used in the form of a powder or in the form of an aqueous solution (liquid composition). In the latter case, the dye solubilizer may be used in combination.

The amount of the dye used in the ink of the present invention is not particularly limited, but is generally from 0.1 to 15% by weight, preferably from 0.5 to 15% by weight of the total weight of the ink.
An amount occupying 10% by weight, more preferably 0.5 to 6% by weight is suitable. The above dyes can be used alone or in combination with conventionally known dyes.

The medium suitable for use in the ink of the present invention is water or a mixed solvent of water and a water-soluble organic solvent. As the water, it is preferable to use deionized water instead of general water containing various ions.

Examples of the water-soluble organic solvent used by mixing with water include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, and isobutyl alcohol. Alcohols having 1 to 5 carbon atoms such as alcohol and n-pentanol; amides such as dimethylformamide and dimethimeacetamide; ketones or keto alcohols such as acetone and diacetone alcohol; ethers such as dioxane; polyethylene glycol And polyalkylene glycols such as polypropylene glycol; ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, Alkylene glycols having an alkylene group containing 2 to 6 carbon atoms, such as silene glycol and diethylene glycol; glycerin; ethylene glycol monomethyl (or ethyl) ether, diethylene glycol monomethyl (or ethyl) ether, triethylene glycol monomethyl (or ethyl) ether Lower alkyl ethers of polyhydric alcohols such as treethylene glycol dimethyl (or ethyl) ether,
Lower dialkyl ethers of polyhydric alcohols such as tetraethylene glycol (or ethyl) ether; sulfolane, N-methyl-2-pyrrolidone, 1,3-dimethyl-
2-imidazolidinone and the like.

An appropriate solvent is selected from the above organic solvents and used. In the case of the dye of the present invention, diethylene glycol or thiodiglycol is particularly preferable for preventing clogging of the ink. From the viewpoint, a nitrogen-containing cyclic compound or an ether compound of a polyalkylene oxide is preferred, and the use of a lower alcohol or a surfactant is preferable for the frequency response. Therefore, a preferred solvent composition in the present invention is a composition containing the above-mentioned various components in addition to water. The content of the water-soluble organic solvent in the ink is generally 2 to 80% by weight, preferably 3 to 7% by weight of the total weight of the ink.
0% by weight, more preferably 4 to 60% by weight.

The water used generally accounts for 10 to 97.5% by weight, preferably 35% by weight or more, more preferably 45% by weight or more of the whole ink. A large amount of low-volatile organic solvent remains in the formed image, which causes problems such as dye migration and image bleeding.

The ink of the present invention may further contain, if necessary, a pH adjuster, a viscosity adjuster, a surface tension adjuster and the like in addition to the above-mentioned components. Examples of the pH adjuster include various organic amines such as diethanolamine and triethanolamine; inorganic alkali agents such as hydroxides of alkali metals such as sodium hydroxide, lithium hydroxide and potassium hydroxide; and organic acids such as lithium acetate. Salts, organic acids and mineral acids.

The ink of the present invention as described above has a viscosity at 25 ° C. of 1 to 20 cps, preferably 1 to 15 cps.
And the surface tension is 30 dyn / cm or more, preferably 40 dyn / cm or more.
It preferably has physical properties of dyn / cm or more and a pH of about 4 to 10.

The recording method using the ink of the present invention is as follows.
An ink jet method is effective as a method, and as a recording material, general plain paper (for example, high quality paper, medium quality paper,
Any recording material such as bond paper), coated paper, OHP plastic film and the like can be used.

The ink of the present invention is particularly suitable when applied to an ink jet recording method of a type in which the ink is ejected by a bubbling phenomenon of the ink by thermal energy,
Discharge is extremely stable and satellite dots are not generated. However, in this case, the thermal properties (for example, specific gravity, thermal expansion coefficient, thermal conductivity, etc.) may be adjusted.

The ink of the present invention is particularly preferably used in an ink jet recording system in which recording is performed by discharging droplets by the action of thermal energy, but it goes without saying that it can also be used as a general writing instrument.

As a method and apparatus suitable for performing recording using the ink of the present invention, there is provided a method in which thermal energy corresponding to a recording signal is applied to ink in a chamber of a recording head and droplets are generated by the thermal energy. And a device.

FIGS. 1, 2 and 3 show examples of the structure of a head which is a main part of the apparatus.

The head 13 includes a glass, ceramic or plastic plate having a groove 14 through which ink passes, and a heating head 15 used for thermal recording (a head is shown in the figure, but is not limited to this). And obtained by bonding. The heating head 15 includes a protective film 16 made of silicon oxide or the like, aluminum electrodes 17-1, 17-2,
Heating resistor layer 18 made of nichrome or the like, heat storage layer 1
9, a substrate 20 having good heat dissipation such as alumina.

The ink 21 has a discharge orifice (fine hole) 2
2, and a meniscus 23 is formed by a pressure (not shown).

When an electric signal is applied to the electrodes 17-1 and 17-2, the area of the heating head 15 indicated by n rapidly generates heat, and bubbles are generated in the ink 21 in contact with the area.
The meniscus 23 protrudes by the pressure, the ink 21 is ejected, the orifice 22 becomes a recording droplet 24, and flies toward the recording material 25. FIG. 3 shows an external view of a multi-head in which many heads shown in FIG. 1 are arranged. The multi-head is manufactured by closely contacting a glass plate 27 having a multi-groove 26 and a heating head 28 similar to that described with reference to FIG.

FIG. 1 shows a head 1 along an ink flow path.
3 is a sectional view, and FIG. 2 is a sectional view taken along line AB in FIG.

FIG. 4 shows an example of an ink jet recording apparatus incorporating such a head.

In FIG. 4, reference numeral 61 denotes a blade as a wiping member, one end of which is held by a blade holding member and serves as a fixed end, forming a cantilever. The blade 61 is disposed at a position adjacent to a recording area of the recording head, and in this example, is held in a form protruding into the movement path of the recording head. Reference numeral 62 denotes a cap, which is provided at a home position adjacent to the blade 61 and has a configuration in which the cap moves in a direction perpendicular to the moving direction of the recording head to abut on the discharge port surface to perform capping. Reference numeral 63 denotes an ink absorber provided adjacent to the blade 61, which is held in a form protruding into the movement path of the recording head, similarly to the blade 61. The blade 61, the cap 62, and the absorber 63 constitute an ejection recovery unit 64, and the blade 61 and the absorber 63 remove water, dust, and the like from the ink ejection port surface.

Reference numeral 65 denotes a recording head which has discharge energy generating means and discharges ink on a recording material facing a discharge port surface provided with discharge ports to perform recording, and 66 denotes a recording head on which the recording head 65 is mounted. A carriage for performing the movement 65. The carriage 66 is slidably engaged with the guide shaft 67, and a part of the carriage 66 is connected to a belt 69 driven by a motor 68 (not shown). As a result, the carriage 66 can move along the guide shaft 67, and the recording head 65 can move the recording area and the adjacent area.

Reference numeral 51 denotes a paper feed unit for inserting a recording material, and 5
Reference numeral 2 denotes a paper feed roller driven by a motor (not shown). With such a configuration, the recording material is fed to a position facing the ejection port surface of the recording head, and is discharged to a discharge section provided with a discharge roller 53 as recording proceeds.

In the above configuration, when the recording head 65 returns to the home position at the end of recording or the like, the cap 62 of the head recovery unit 64 is retracted from the moving path of the recording head 65, but the blade 61 protrudes into the moving path. I have. As a result, the ejection openings of the recording head 65 are wiped.
When capping is performed with the cap 62 in contact with the ejection surface of the recording head 65, the cap 62 moves so as to protrude into the movement path of the recording head.

When the recording head 65 moves from the home position to the recording start position, the cap 62 and the blade 6
1 is at the same position as the position at the time of wiping described above.
As a result, the ejection port surface of the recording head 65 is also wiped during this movement.

The above-described movement of the print head to the home position is performed not only at the end of printing or at the time of ejection recovery, but also at a predetermined interval while the printing head moves through the printing area for printing. The wiping is performed in accordance with this movement.

FIG. 5 is a view showing an example of an ink cartridge containing ink supplied to the head via an ink supply member, for example, a tube. Here, reference numeral 40 denotes an ink storage section storing the supply ink, for example, an ink bag, and a rubber stopper 42 is provided at the tip thereof. By inserting a needle (not shown) into this stopper 42,
The ink in the ink bag 40 can be supplied to the head. An ink absorber 44 receives the waste ink. It is preferable for the present invention that the ink container has a liquid contact surface with the ink formed of polyolefin, particularly polyethylene.

The ink jet recording apparatus used in the present invention is not limited to the one in which the head and the ink cartridge are separated from each other as described above, but is also suitable for the one in which they are integrated as shown in FIG. Used.

In FIG. 6, reference numeral 70 denotes a recording unit, in which an ink storage section for storing ink, for example, an ink absorber is stored, and the ink in the ink absorber has a plurality of orifices. Head part 71
Are ejected as ink droplets from the ink. As the material of the ink absorber, it is preferable for the present invention to use polyurethane.

Reference numeral 72 denotes an atmosphere communication port for communicating the inside of the cartridge with the atmosphere.

This recording unit 70 is used in place of the recording head shown in FIG.
6 is detachable.

[0061]

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. In the following description, "parts" are based on weight unless otherwise specified.

Example 1 Specific Example No. Synthesis of 2-1 (1) Synthesis of monoazo compound <1> Disperse 0.2 mol of dimethoxyaniline in 400 ml of water, dissolve by adding hydrochloric acid, and filter.

<2> Dissolve 0.2 mol of p-ethylaniline in 300 ml of dilute hydrochloric acid, add an aqueous solution of 200 g of ice, 40 g of hydrochloric acid and 0.2 mol of sodium nitrite, and add
Stir for a minute and diazotize and add sulfamic acid.

<3> 200 g of ice is added to the above, and the diazo solution is poured while cooling with ice. At the same time, a 20% aqueous sodium hydroxide solution is added to keep the pH at 3-4.

<4> After stirring for 3 hours under ice-cooling, 50 g of sodium chloride is added, salted out, and filtered by suction. Dilute hydrochloric acid (pH ~
1) Disperse the mixture in 1.5 l, stir, add 50 g of sodium chloride and filter by suction.

(2) Synthesis of disazo compound <5> The above monoazo compound wet cake was added to DMF30.
Dissolve in 0 g, add 150 g of ice, 60 g of hydrochloric acid and an aqueous solution of 0.2 mol of sodium nitrite, stir for 2 hours while cooling with ice, and add diazotized sulfamic acid.

<6> 0.2 mol of gamma acid in 200 ml of water
And melted with sodium hydroxide.
Add g.

<7> The above diazo solution is poured while cooling the mixture with ice. PH 9-10 with 20% sodium hydroxide
To keep.

<8> After stirring under ice-cooling for 5 hours, 30 g of sodium acetate was added and centrifuged. The precipitate was dissolved in 1.5 l of water, 20 g of sodium acetate was added, the pH was adjusted to 4 with acetic acid, and the mixture was centrifuged.

(3) Synthesis of trisazo compound <9> The wet cake of the above disazo compound was added to DMF300
g, 100 g of ice, 60 g of hydrochloric acid and an aqueous solution of 0.2 mol of sodium nitrite are added, and the mixture is stirred for 2 hours while cooling with ice, and diazotized and sulfamic acid is added.

<10> 0.2 mol of m-phenylenediamine-4-sulfonic acid is dispersed in 300 ml of water, dissolved by adding sodium hydroxide, and 150 g of ice is added.

<11> The above diazo solution is poured while cooling the mixture with ice. Stir at pH 4-5 for 7 hours.

<12> 30 g of sodium acetate is added and centrifuged. The precipitate is dispersed in 1 l of water, the pH is adjusted to 10, and 20 g of sodium acetate is added and centrifuged.

<13> The precipitate is dispersed in 3 liters of a 1: 1 mixture of ethanol and water, dissolved by heating, filtered, and the filtrate is cooled. The deposited precipitate is collected by filtration and dried. Yield 65 g. Maximum absorption wavelength 5
76 nm (water).

(Example 2) Synthesis of 3-1 It is synthesized in the same manner by using m-chloroaniline instead of p-ethylaniline. Maximum absorption wavelength 578 nm (water).

Example 3 Specific Example No. Synthesis of 4-1 It is synthesized in the same manner by using 2-amino-4-chlorotoluene instead of P-ethylaniline. Maximum absorption wavelength 575 nm (water).

(Example 4) Synthesis of 5-1 The same synthesis is performed by using m-toluidine instead of the above-mentioned p-ethylaniline. Maximum absorption wavelength 575
nm (water).

Examples 5 to 16 (1) Preparation of Ink The components shown in Table 1 below were mixed and dissolved, and filtered using a filter having a pore size of 0.2 μm to obtain inks shown in Table 1 below. In addition,
All the dyes used were desalted and purified by a suitable method such as reverse osmosis and ultrafiltration.

[0079]

[Table 1]

As described above, the inks of all the examples were obtained as good black inks.

(2) Example of Ink Use An on-demand type multi-head (orifice size 50 ×) is used in which each of the inks shown in Table 1 is applied to the ink in the recording head to generate thermal droplets to generate droplets for recording.
Table 2 shows the evaluation results of the printing performance, ejection performance, and storage stability when printing was carried out by mounting on a recording apparatus having a recording device of 40 μm, a driving voltage of 30 V, and a frequency of 4 kHz. The evaluation and conditions of each evaluation item are as follows.

(1) Print density: Printing was performed on a commercial continuous slip sheet by simultaneous driving of all nozzles, and a patch was prepared. The patch was naturally dried in a room for 24 hours, and then the optical density of the patch was measured. Was evaluated. A: Optical density is 1.31 or more B: Optical density is 1.26 to 1.30 C: Optical density is 1.10 to 1.25 D: Optical density is 1.09 or less

(2) Occurrence rate of bleeding: 300 dots were continuously printed on a commercially available continuous slip sheet so that they did not touch each other, allowed to dry naturally in a room for 24 hours, and then irregularly shaped or irregularly bleeding with a microscope. The number of generated dots was counted, and the percentage was evaluated according to the following criteria. A: 6% or less B: 7 to 12% C: 13 to 35% D: 36% or more

(3) Fixing property (print drying property): After printing alphanumeric characters on a commercially available continuous slip sheet, 10, 20, 30,
After 40, 50 and 60 seconds, the printed portion was rubbed with a lens cleaning paper, and the number of seconds until the printed portion was not stained was measured and evaluated according to the following criteria. A: Within 10 seconds B: 11 to 20 seconds C: 21 to 40 seconds D: 41 seconds or more

(4) Indoor discoloration: A patch is created by simultaneously driving all nozzles on coated paper (designated paper for Canon PixelPro ^™ ) to create a patch, and the degree of discoloration after exposure to room light for three months is determined by color difference. ΔH ^* (hue difference) was calculated and evaluated according to the following criteria. A: [Delta] H ^* is less than 5 B: ΔH ^* is 5~19.99 C: ΔH ^* is 20 or more

(5) Water resistance: Tap water is placed in a petri dish and allowed to stand. The patch evaluated in the above (1) was immersed gently in it, left for 15 minutes and dried.

(5a) The optical density was measured in the same manner as in (1), and the residual optical density (optical density after immersion / optical density before immersion × 100;%) was calculated and evaluated according to the following criteria. . A: Remaining optical density is 90% or more B: Remaining optical density is 80 to 89% C: Remaining optical density is 60 to 79% D: Remaining optical density is 59% or less

(5b) The extent to which the dye in the printed portion of the paper flowed out, re-dyed on the white background, and contaminated was evaluated according to the following criteria. A: Almost no contamination. B: Less contamination. C: There is much contamination.

(6) Ejection stability: Printed on 100 continuous slip sheets and evaluated according to the following criteria. A: No abnormality B: Non-discharge or print disorder

(7) Clogging (adhesion recovery property): Left in a thermostat at 60 ° C. for one month, then left at room temperature for 24 hours, and after performing a recovery operation (absorption operation by pumping), printing was performed. Evaluation was made according to the following criteria. A: Return to a normal printing state within 2 recovery operations B: Return to a normal printing state within 3 to 5 recovery operations C: Non-discharge or print disturbance occurs after 6 to 10 recovery operations

(8) Storage stability: 100 cc of each ink was placed in a heat-resistant glass bottle, sealed, stored in a thermostat at 60 ° C. for 3 months, and printed on 100 sheets of continuous slip paper.
Evaluation was made according to the following criteria. A: No abnormality B: Non-discharge, print disorder or discoloration

[0092]

[Table 2]

(Comparative Examples 1 to 12) The inks shown in Table 4 below were prepared using the dye compounds shown in Table 3 below.
The same evaluation was performed as in the case of. Table 5 shows the results.

[0094]

[Table 3]

[0095]

[Table 4]

[0096]

[Table 5]

[0097]

[Table 6]

[0098]

[Table 7]

[0099]

As described above, in the present invention, by using the compound (dye) represented by the general formula (A) as the dye in the ink, not only water resistance but also various properties required for printing on plain paper can be obtained. An ink that satisfies can be obtained. Further, it is possible to provide a black image having high image quality, excellent resolution, and little discoloration and excellent fastness even when printed on coated paper.

The ink of the present invention has an ink pH of 4
Since the above properties are sufficiently exhibited even in the vicinity of neutrality of from 10 to 10, the addition of a strongly alkaline substance as described in JP-A-56-57862 is not required, which is preferable in terms of safety.

Further, even when the compound of the present invention is applied to an ink jet recording method in which ink is ejected by the action of heat energy, it does not generate any deposit on the heater and can be used stably for a long time. is there. Also, there is no change in physical property values or precipitation of solid content during storage.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a head section of an ink jet recording apparatus.

FIG. 2 is a vertical sectional view of a head section of the ink jet recording apparatus.

FIG. 3 is an external perspective view of a head obtained by multiplying the head shown in FIGS. 1 and 2.

FIG. 4 is a perspective view illustrating an example of an inkjet recording apparatus.

FIG. 5 is a longitudinal sectional view of the ink cartridge.

FIG. 6 is a perspective view of an inkjet cartridge (same as a recording unit).

[Explanation of symbols]

 Reference Signs List 61 wiping member 62 cap 63 ink absorber 64 discharge recovery section 65 recording head 66 carriage

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-61-285276 (JP, A) JP-A-55-152747 (JP, A) JP-A-61-264060 (JP, A) JP-A-62 257971 (JP, A) JP-A-54-144067 (JP, A) JP-A-4-136077 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09B 31/18 C09B 31 / 22 C09D 11/00 C09D 11/02

Claims (22)

(57) [Claims] An azo compound represented by the general formula (A) (However, R ₁ , R ₂ or R ₃ each represents a hydrogen atom and a carbon number of 1 to
Alkyl group, methoxy group, halogen atom, COO
M, represents a group selected from the group consisting of COOR _4, wherein R ₄ represents an alkyl group having 1 to 4 carbon atoms, M represents an alkali metal or an ammonium or organic ammonium. ) 2. The following No. The compound according to claim 1, which is selected from 1 to 12, wherein M represents an alkali metal or ammonium or an organic ammonium. [Outside 2] [Outside 3] [Outside 4] 3. A black dye composition containing an azo compound represented by the following general formula (A) as a main component. [Outside 5] (However, R ₁ , R ₂ or R ₃ each represents a hydrogen atom and a carbon number of 1 to
Alkyl group, methoxy group, halogen atom, COO
M, represents a group selected from the group consisting of COOR _4, wherein R ₄ represents an alkyl group having 1 to 4 carbon atoms, M represents an alkali metal or an ammonium or organic ammonium. ) 4. The following No. 4. The black dye composition according to claim 3, which contains an azo compound selected from 1 to 12 as a main component (M represents an alkali metal, ammonium, or organic ammonium). [Outside 6] [Outside 7] [Outside 8] 5. An ink containing a recording agent and a liquid medium for dissolving or dispersing the recording agent, comprising an azo compound represented by the following general formula (A) as the recording agent. [Outside 9] (However, R ₁ , R ₂ or R ₃ each represents a hydrogen atom and a carbon number of 1 to
Alkyl group, methoxy group, halogen atom, COO
M, represents a group selected from the group consisting of COOR _4, wherein R ₄ represents an alkyl group having 1 to 4 carbon atoms, M represents an alkali metal or an ammonium or organic ammonium. ) 6. The recording material of the following No. The ink according to claim 5, wherein the ink comprises at least one selected from 1 to 12 (M represents an alkali metal or an organic ammonium). [Outside 10] [Outside 11] [Outside 12] 7. The ink according to claim 5, wherein the pH of the ink is in the range of 4 to 10. 8. The ink according to claim 5, wherein the recording agent accounts for 0.1 to 15% by weight of the total weight of the ink. 9. The ink according to claim 5, wherein the liquid medium contains a mixed solvent of water and a water-soluble organic solvent. 10. The content of water is 10 to 9 of the total ink.
The ink according to claim 9, wherein the ink occupies 7.5% by weight. 11. The ink according to claim 9, wherein the content of the water-soluble organic solvent accounts for 2 to 80% by weight of the total weight of the ink. 12. The ink according to claim 9, wherein the water-soluble organic solvent contains glycol. 13. The ink according to claim 12, wherein the glycol is diethylene glycol and / or thiodiglycol. 14. The ink according to claim 5, which is used for ink jet. 15. The ink according to claim 14, wherein the ink comprises at least a recording agent, a water-soluble organic solvent, and water. 16. The ink according to claim 15, wherein the water-soluble organic solvent contains glycol. 17. The ink according to claim 16, wherein the glycol is diethylene glycol and / or thiodiglycol. 18. The ink according to claim 17, which contains at least 2-propanol and / or triethanolamine as an additive. 19. The ink according to claim 18, wherein the ink comprises at least a recording agent, water, thiodiglycol, 2-propanol and triethanolamine. 20. An ink jet recording method for performing recording on a recording material using ink droplets, wherein the ink is the ink according to claim 5. 21. The ink jet recording method according to claim 20, wherein the ink is ejected by applying thermal energy to the ink. 22. The ink jet recording method according to claim 20, wherein the recording material is uncoated paper or coated paper.