JP2002285054A - Ink and ink-jet recording device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink-jet ink capable of obtaining high durability which has not been achievable by a prior art, in particular, suitable for thermal ink-jet recording, and to provide an ink-jet device capable of achieving high durability using the same. SOLUTION: The ink at least comprises a colorant, a liquid for dispersing or dissolving the colorant and a carbon black, wherein the carbon black content is 0.1 wt.% or less. The ink-jet recording device using the ink is also provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink having excellent reliability, particularly durability, suitable for ink jet recording, and an ink jet recording apparatus using the ink.

[0002]

2. Description of the Related Art In an ink jet recording method, recording is performed by flying small ink droplets and attaching the ink to a recording medium such as paper. In particular, JP-B-61-59911, JP-B-61-59912, and JP-B-61-5
No. 9914, namely, an ink jet recording method (thermal ink jet recording) in which an electrothermal converter is used as a discharge energy supply means, and thermal energy is applied to ink to generate droplets by generating bubbles. According to the method, a high-density multi-orifice of the recording head can be easily realized, and a high-resolution and high-quality image can be recorded at a high speed.

In the above thermal ink jet recording method, the temperature of a heater provided in a nozzle is instantaneously exposed to a high temperature of several hundred degrees, so that thermal decomposition products of ink components and the like may be deposited on the heater surface. is there. Since such deposits cause heat conduction from the heater to the ink to be hindered, the ink does not foam properly, and as a result, a defect occurs in printing. Deposition of a substance derived from the ink component on such a heater surface is as follows.
This is called kogation and is an obstacle to the high durability of the thermal ink jet recording system. Conventionally, as means for preventing kogation from the ink composition side,
A method for reducing the content of inorganic impurities in the ink, a method for improving the purity of the colorant by purifying the colorant such as a dye to be contained in the ink, and the like are disclosed. On the other hand, recently, there has been an increasing demand for low running cost of ink jet recording, and there is a demand for higher durability than before.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an ink-jet ink capable of obtaining a high durability which cannot be achieved by the prior art, particularly an ink-jet ink suitable for thermal ink-jet recording, and an ink-jet ink suitable for the ink-jet recording. An object of the present invention is to provide an ink jet recording apparatus which can achieve high durability using the ink jet recording method.

[0005]

The above objects are achieved by the present invention described below. The present invention provides an ink comprising at least a colorant, a liquid medium in which the colorant is dispersed or dissolved, and carbon black, and the content of the carbon black is 0.1 wt% or less. ,
And an ink jet recording apparatus using the ink.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in detail with reference to preferred embodiments. The present inventors have conducted intensive studies in order to solve the above-described problems of the related art, and as a coloring agent,
By incorporating carbon black in a liquid for dispersing or dissolving the same within the range of 0.1 wt% with respect to the total amount of the ink, the above-mentioned problem is solved, and high durability that cannot be achieved by the conventional technology can be obtained. In particular, the present invention has been found to provide an inkjet ink suitable for thermal inkjet recording. Hereinafter, the factors estimated as the action of carbon black in the present invention will be described.

When the ink of the present invention having the above structure is used for thermal ink jet recording, first, carbon black present in the ink in a range of 0.1 wt% or less in a nozzle of a thermal ink jet recording head in an initial stage of recording. Deposited on a heater surface provided therein to form a thin film on the heater surface. However, since the content of carbon black in the ink is small, the film formed of carbon black is extremely thin and does not adversely affect the heat conduction from the heater to the ink. As recording progresses and the cumulative number of electric pulses for heating the heater increases, kogation substances derived from the ink components may be deposited on the carbon black layer. In a system without the carbon black layer, the kogation material accumulates on the heater surface as the number of repeated pulses increases. In contrast,
It is presumed that the carbon black layer repeatedly peels and adheres on the heater surface in the process of repeatedly generating and disappearing bubbles generated by ink film boiling, thereby improving the durability.

The ink of the present invention contains a colorant, a liquid for dispersing or dissolving the colorant, and carbon black as essential components, and has a carbon black content of 0.1 wt.
%. Hereinafter, each component constituting the ink of the present invention will be described in detail.

<Carbon black / content thereof> By including a specific amount of carbon black in the ink, the durability of ink jet recording can be improved as described above. On the other hand, since the addition amount of carbon black may be as small as 0.1 wt% or less, even if the ink is a color ink, it does not affect the color. Further, more preferable content of carbon black in the ink of the present invention is, for example, 0.0
It is preferably less than 5 wt%, more preferably 0.005 to less than 0.02 wt%. By doing so, it is possible to more effectively suppress the accumulation of kogation on the heating heater without affecting the color tone of the ink. As the carbon black used in the present invention, conventionally known channel blacks, furnace blacks and the like can be used. Further, for example, self-dispersion type carbon black subjected to various surface treatments can be used without any problem.

<Colorant / Content thereof> First, as the colorant that can be used in the ink of the present invention, conventionally known dyes such as dyes and pigments can be appropriately used, and there is no particular limitation. In particular, it is preferable to use a water-soluble coloring agent. For example, a water-soluble anionic dye, a direct dye, an acid dye, a reactive dye, or the like, which is a conventionally known water-soluble dye, can be used. The content of these dyes in the ink may be, for example, 0.5 to 15 with respect to the total weight of the ink in consideration of the density of the recorded image and the ejection characteristics of the ink.
% By weight, particularly preferably 1 to 12% by weight.
Specific water-soluble dyes that can be used in the present invention will be described later.

<Liquid Medium> The liquid medium used in the present invention for dispersing or dissolving the ink component as described above can hold the carbon black and the water-soluble colorant in a solution state. It can be a component, particularly a component of an ink jet recording ink. Specific examples of the liquid medium used in the present invention include:
The aqueous medium preferably contains at least water as a component thereof. Further, a water-soluble organic solvent may be mixed to increase the solubility of each component of the ink or to adjust various characteristics of the ink. The ratio of water to the total weight of the ink is, for example, 20 to 95% by weight, preferably 40 to 95% by weight, and more preferably 6 to 95% by weight.
The content is preferably set to 0 to 95% by weight. Specific liquid media that can be used in the present invention will be described later.

<Specific Examples of Water-Soluble Dyes> Examples of the water-soluble dyes having an anionic group which can be used as the colorant of the ink of the present invention include the following.

(Black Ink) Examples of dyes used in black ink include C.I. I. Direct Black 17, C.I. I. Direct Black 19, C.I. I.
Direct Black 22, C.I. I. Direct Black 31, C.I. I. Direct Black 32, C.I. I. Direct Black 51, C.I. I. Direct Black 6
2, C.I. I. Direct Black 71, C.I. I. Direct Black 74, C.I. I. Direct black 11
2, C.I. I. Direct Black 113, C.I. I. Direct Black 154, C.I. I. Direct Black 1
68, C.I. I. Acid Black 2, C.I. I. Acid Black 48, C.I. I. Acid black 110, C.I.
I. Reactive Black 1, C.I. I. Reactive Black 8, C.I. I. Reactive black 12, C.I.
I. Reactive Black 13, C.I. I. Food black 1, and C.I. I. Food Black 2 and the like.

(Yellow Ink) Examples of dyes used for yellow ink include C.I. I. Acid Yellow 11, C.I. I. Acid Yellow 17, C.I. I. Acid Yellow 23, C.I. I. Acid Yellow 25,
C. I. Acid Yellow 29, C.I. I. Acid Yellow 42, C.I. I. Acid Yellow 49, C.I. I. Acid Yellow 61, C.I. I. Acid Yellow 71,
C. I. Direct Yellow 12, C.I. I. Direct Yellow 24, C.I. I. Direct Yellow 26, C.I.
I. Direct Yellow 44, C.I. I. Direct Yellow 86, C.I. I. Direct Yellow 87, C.I. I.
Direct Yellow 98, C.I. I. Direct Yellow 100, C.I. I. Direct Yellow 130, C.I. I,
And Direct Yellow 142.

(Magenta Ink) Examples of dyes used in magenta ink include C.I. I. Acid Red 1, C.I.
I. Acid Red 6, C.I. I. Acid Red 8,
C. I. Acid Red 32, C.I. I. Acid Red 35, C.I. I. Acid Red 37, C.I. I. Acid Red 51, C.I. I. Acid Red 52, C.I. I. Acid Red 80, C.I. I. Acid Red 85, C.I.
I. Acid Red 87, C.I. I. Acid Red 9
2, C.I. I. Acid Red 94, C.I. I. Acid red 115, C.I. I. Acid Red 254, C.I. I.
Acid Red 289, C.I. I. Direct Red 1,
C. I. Direct Red 4, C.I. I. Direct Red 13, C.I. I. Direct Red 17, C.I. I. Direct Red 23, C.I. I. Direct Red 28,
C. I. Direct Red 31, C.I. I. Direct Red 62, C.I. I. Direct Red 79, C.I. I. Direct Red 81, C.I. I. Direct Red 83,
C. I. Direct Red 89, C.I. I. Direct Red 227, C.I. I. Direct Red 240, C.I.
I. Direct Red 242, and C.I. I. Direct Red 243 and the like.

(Cyan Ink) As the dye used for the cyan ink, C.I. I. Acid Blue 9, C.I. I.
Acid Blue 22, C.I. I. Acid Blue 40,
C. I. Acid blue 59, C.I. I. Acid Blue 93, C.I. I. Acid blue 102, C.I. I. Acid blue 104, C.I. I. Acid blue 113, C.I.
I. Acid blue 117, C.I. I. Acid Blue 1
20, C.I. I. Direct Blue 6, C.I. I. Direct Blue 22, C.I. I. Direct Blue 25, C.I.
I. Direct Blue 71, C.I. I. Direct Blue 78, C.I. I. Direct Blue 86, C.I. I. Direct Blue 106 and C.I. I. Direct blue 19
9 and the like.

(Other Preferred Dyes) Further, preferred dyes that can be used in the ink of the present invention include:
Dyes having one or more -COOM groups (M represents an alkali metal or ammonium) in the molecule are mentioned. Specifically, for example, dyes represented by the following general formulas (II) to (V) are effectively used in the present invention.

[0018] [In the formula (II), A and B represent a hydroxyl group or a hydrogen atom, C represents a hydrogen atom or SO ₃ M, and D represents a SO ₃ M
Respectively. M represents an alkali metal, ammonium or organic ammonium. ]

[0019]

[In the above formula (III), G represents any of the following structural formulas (1) to (4), and Z represents NHC
It represents H ₂ CH ₂ OH, N (CH ₂ CH ₂ OH) _{2 and the} like, and in the following structural formula (3), R and R ′ represent a hydrogen atom or a lower alkyl group. ]

[0021]

[In the above formula (IV), J and J ¹ each independently represent any of the following structural formulas (5) to (7);

L represents the following structural formula (8) or (9);

X represents any of the following structural formulas (10) to (12);

R ^{1 to} R ⁴ in the above formula (IV) represent a hydrogen atom,
R ⁵ in the above structural formula (5) represents a hydrogen atom, a lower alkyl group or the like, and represents a lower alkyl group or the like;
W represents a hydrogen atom, —CN, an amide group, a pyridinium group, or —COOH, T represents an alkyl group, m represents an alkylene group of 2 to 8, and the above structural formula ( 7) in B represents a hydrogen atom or -COOH, Z in the above structural formula (10) to (12), an alkoxyl group, -OH, alkyl amino group or -NH ₂
Y represents a hydrogen atom, -Cl or -CN, and E represents -Cl or -CN. ]

[0026]

[In the above formula (V), J is the following structural formula (1)
3)

L represents the following structural formula (14) or (15);

X represents any of the following structural formulas (16) to (18): R ¹ and R ² in the above formula (V) represent a hydrogen atom, a lower alkyl group or the like, and in the above structural formulas (16) to (18),
Is an alkoxyl group, -OH, an alkylamino group or-
Represents any such NH _2, Y is a hydrogen atom, represents any -Cl or -CN, E represents -Cl or -CN. )

<Relationship Between the Colorant and pH of the Ink> When the above-mentioned colorant, particularly a water-soluble colorant containing —COOM in the molecule, is contained in the ink, the pH of the ink is adjusted to 9.5 to 12. It is particularly preferable to adjust to about 9.5 to 11. That is, when the pH of the ink is in this range,
The solubility of the colorant in the aqueous medium is further improved, and a change in characteristics of the ink during storage can be suppressed. Further, by setting the pH of the ink within the above range, generation of kogation on the heating heater is extremely strongly controlled.

<Specific Examples of Water-Soluble Organic Solvent> Next, examples of the water-soluble organic solvent which may be contained in the liquid medium in the ink of the present invention include monohydric alcohols such as methanol, ethanol and isopropyl alcohol. Ketone or keto alcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; oxyethylene such as diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol and polypropylene glycol; Oxypropylene addition polymer; ethylene glycol, propylene glycol, trimethylene glycol, butylene glycol,
Alkylene glycols having an alkylene group containing 2 to 6 carbon atoms, such as hexylene glycol; triols, such as 1,2,6-hexanetriol; thiodiglycol; glycerin; ethylene glycol monomethyl (or ethyl) ether, diethylene glycol Lower alkyl ethers of polyhydric alcohols such as monomethyl (or ethyl) ether and triethylene glycol monomethyl (or ethyl) ether; polyhydric such as triethylene glycol dimethyl (or ethyl) ether and tetraethylene glycol dimethyl (or ethyl) ether And lower dialkyl ethers of alcohol. The content of the water-soluble organic solvent is generally in the range of 0 to 40%, preferably 2 to 30% by weight based on the total weight of the ink. When the above-mentioned media are used in combination, they can be used alone or as a mixture.
They are polyhydric alcohols, ketones, glycerin, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, thiodiglycol, propylene glycol, dipropylene glycol, tripropylene glycol and derivatives thereof (among others, alkyl ethers thereof).

<Other Components> The ink of the present invention contains various other humectants, defoamers, viscosity modifiers, surface tension modifiers, and p-sodium as long as the effects of the ink are not impaired.
An H adjuster or the like may be added as necessary. As the humectant, conventionally known urea, ethylene urea, or the like can be used.

<Ink Jet Recording Apparatus> Next, an ink jet recording apparatus which can use the above-described ink of the present invention and an image recording method using the same will be described.

(Head Configuration) FIG. 1 shows an embodiment of a recording head constituting one of the main parts of an ink jet recording apparatus of the type in which ink is ejected by utilizing thermal energy, and an orifice from which ink is ejected. It is an outline sectional view of a direction which crosses a part lengthwise. FIG. 2 is a sectional view taken along line AA of FIG. In FIG. 1 and FIG.
Is used to bond a glass, ceramic or plastic plate or the like having a groove 14 through which ink passes, to a heating head 15 used for thermal recording (a head is shown in the figure, but is not limited to this). Obtained. The heating head 15 includes a protective film 16 formed of silicon oxide or the like, aluminum electrodes 17-1 and 17-2, a heating resistor layer 18 formed of nichrome or the like, a heat storage layer 19, and a substrate having good heat dissipation such as alumina. It consists of 20.

In the recording head 13, the ink 21
Reaches a discharge orifice (fine hole) 22, and forms a meniscus 23 with a predetermined pressure P. 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, and the pressure is increased. , The meniscus 23 protrudes, and the ink 2
1 is ejected, flies toward a recording medium (for example, paper) 25, adheres to an image recording area of the recording medium 25, and an image is recorded.

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.

In the configuration of the head described above, the size of the orifice is not particularly limited, and may be appropriately set according to the desired image quality. However, with the recent demand for higher image quality, miniaturization of the orifice size has been studied. Specifically, for example, the amount of ink ejected from the orifice by one ejection operation is 0.1 to
The miniaturization of the orifice to be 40 picoliters (pl), particularly 0.1 to 30 pl has been studied. In an orifice of such a size, it is one of the technical goals particularly preferable to form a high-quality image by stably re-discharging the ink after the recording is temporarily stopped. The ink of the present invention can be cited as one of extremely effective techniques capable of overcoming this technical goal.

Even when the orifice is not miniaturized as described above, the use environment is diversified with the spread of the ink jet recording apparatus, specifically, for example, the environment where the ambient temperature is 5 ° C. or less. When the inkjet recording apparatus is used in a room (for example, in a cold area where heating is not effective indoors or outdoors), as described above, ink discharge may occur due to clogging of the orifice. This point is one of the important technical goals to be overcome from the viewpoint of further dissemination. The ink of the present invention can be cited as one of extremely effective techniques capable of overcoming this technical goal.

(Recording Apparatus) FIG. 4 shows an example of an ink jet recording apparatus incorporating the above-described recording 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 to become a fixed end, and forms a cantilever. The blade 61 is disposed at a position adjacent to the recording area of the recording head, and in the case of the apparatus shown in FIG. 4, is held in a form protruding into the movement path of the recording head. 6
Reference numeral 2 denotes a cap, which is disposed at a home position adjacent to the blade 61 and has a configuration in which the cap moves in a direction perpendicular to the direction of movement of the recording head and comes into contact with the ejection port surface to perform capping. Further, an absorber 63 is provided adjacent to the blade 61 and, like the blade 61, is held in a form protruding into the movement path of the recording head. 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 moisture, dust, and the like from the ink ejection port surface.

Numeral 65 has discharge energy generating means,
A recording head 66 ejects ink onto a recording medium facing an ejection port surface provided with ejection ports to perform recording. Reference numeral 66 denotes a carriage for mounting the recording head 65 and moving the recording head 65. It is. 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). Thus, the carriage 66 can move along the guide shaft 67, and the recording head 65 can move the recording area and the adjacent area. 5
Reference numeral 1 denotes a paper feed unit for inserting recording paper as a recording medium, and 52 denotes a paper feed roller driven by a motor (not shown). With such a configuration, the recording paper is fed to a position facing the ejection opening surface of the recording head, and is discharged to a discharge section provided with a discharge roller 53 as the recording progresses.

In the above configuration, when the recording head 65 returns to the home position at the end of recording or the like, the head recovery section 64
Is retracted from the moving path of the recording head 65, but the blade 61 protrudes into the moving path. As a result, the ejection port surface of the recording head 65 is 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 61 are at the same positions as those at the time of wiping described above. As a result, even in this movement, the recording head 65
Is wiped. The above-described movement of the print head to the home position is performed not only at the end of printing and at the time of ejection recovery, but also to the home position adjacent to the printing area at a predetermined interval while the printing head moves through the printing area for printing. Then, the wiping is performed along with this movement.

(Ink Cartridge) FIG. 5 is a diagram showing an example of an ink cartridge in which ink supplied to a head via an ink supply member, for example, a tube is stored. Here, reference numeral 40 denotes an ink storage unit that stores the supply ink, for example, an ink bag, and a rubber stopper 42 is provided at the end thereof. By inserting a needle (not shown) into the stopper 42, the ink in the ink bag 40 can be supplied to the head. 44 is an absorber for receiving the waste ink. It is preferable that the ink container has a liquid contact surface with the ink formed of polyolefin, particularly polyethylene. The ink of the present invention can be suitably used not only in an ink jet recording apparatus in which the head and the ink cartridge are separated as described above, but also in an ink jet recording apparatus in which they are integrated as shown in FIG. .

(Recording Unit) In FIG. 6, reference numeral 70 denotes a recording unit, in which an ink storage portion for storing ink, for example, an ink absorber is stored, and the ink in the ink absorber is stored. The ink is ejected as ink droplets from a head 71 having a plurality of orifices. It is preferable to use polyurethane as the material of the ink absorber. Reference numeral 72 denotes an atmosphere communication port for communicating the inside of the recording unit with the atmosphere. The recording unit 70 is used in place of the recording head shown in FIG. 4, and is detachable from the carriage 66.

<Ink Set> The ink of the present invention having the above-described structure can be prepared by, for example, selecting yellow, magenta, cyan, red,
It can be a green, blue or black ink. Each of these inks may be used alone for image recording, but by combining two or more different color inks,
An ink set that can be suitably used for forming a color image can also be provided. 2 containing the same color tone and different colorants
By combining two or more inks or combining two or more inks having the same color tone but different densities, it is possible to provide an ink set that can be suitably used for high-gradation image formation. .

When an image is formed using these ink sets, for example, an ink jet recording apparatus in which four recording heads shown in FIG. 3 are arranged on a carriage can be used. FIG. 8 is an example of the embodiment,
86, 87, 88 and 89 are recording heads for discharging, for example, yellow, magenta, cyan and black inks, respectively. These recording heads are arranged in the ink jet recording apparatus having the configuration described above,
Ink of each color is ejected from a recording head in accordance with a recording signal to form an image. Also, in FIG.
Although the example which used one was shown, it is not limited to this, for example,
As shown in FIG. 7, there is also an embodiment in which the above four ink cartridges are used to perform color image recording by dividing the ink flow path with one head.

The case where the ink according to the present invention is used in an apparatus for applying thermal energy corresponding to a recording signal to ink and discharging ink from the thermal energy and an image recording method using the apparatus has been described. Was. However, the ink of the present invention can also be used in an ink jet recording apparatus that discharges the ink by mechanical energy and an image recording method using the same, whereby the same excellent effects can be obtained.

[0048]

Next, the present invention will be described in more detail with reference to examples. <Examples 1 to 6> Inks having the following compositions were prepared and filled in a color ink tank of a Canon bubble jet printer BJC-620J.
⁸ times), and the dot diameter before and after the endurance is determined by Canon HR-101, a high-grade paper for high quality.
It was compared by printing on the top. Table 1 shows the amounts of the colorant and carbon black used in each of the inks of Examples 1 to 5. Table 1 shows the amount of carbon black added.
It is described in terms of the solid content in the ink.

(Ink composition) 3% by weight of each dye 10% by weight of glycerin Carbon black (Cabojet 200) Water remaining amount

[0050]

<Comparative Examples 1 to 3> As Comparative Example, Example 3 was used.
The inks of Comparative Examples 1 to 3 were prepared by using the following coloring agents except for carbon black from the ink composition of Comparative Examples 1 to 3.

[0052]

(Evaluation) <Durability> Examples 1 to 6 and Comparative Examples 1 and 2 obtained above.
The ink endurance test was performed using each of the three inks.
Table 3 shows the obtained evaluation results. At that time, the ratio of the dot diameter before and after the durability test [dot diameter (after the durability test) / dot diameter (before the durability test)] was taken and evaluated according to the following criteria. ◎: 0.95 or more ：: 0.90 to less than 0.95 Δ: 0.79 to less than 0.9 ×: less than 0.79

<Color Tone of Image> Regarding the color tone of the image obtained in the above durability test, the color difference ΔE of CIE Lab when compared with the color tone of each colorant used was determined and evaluated according to the following criteria. Table 3 shows the obtained results. ：: ΔE is less than 5 Δ: ΔE is 5 or more and less than 10 ×: ΔE is 10 or more

[0055]

As shown in Table 3, the durability of the inks of Examples 1 to 6 containing carbon black was as follows.
It was confirmed that the durability of the ink No. 3 was improved as compared with the durability. However, in the images using the inks of Example 1 and Example 4, the images using the inks of Comparative Examples 1 and 3 which did not contain carbon black using the same coloring agent as those of these Examples were used. Although there was no problem in practical use, the color difference was slightly observed. On the other hand, Examples 2, 3, and 5
When the inks of Nos. 6 and 6 were used, an image having a color tone almost equal to that of the ink of the comparative example was obtained. As a result, it was confirmed that when the amount of carbon black contained in the ink was set to a more preferable range, the durability was improved without any influence on the color tone.

[0057]

As described above, according to the present invention,
Provided is an inkjet ink having high durability that cannot be achieved by the conventional technology, particularly an inkjet ink suitable for thermal inkjet recording, and an inkjet recording apparatus capable of achieving high durability by using such an ink.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a head of an ink jet recording apparatus.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a schematic explanatory diagram of a multi-head.

FIG. 4 is a schematic perspective view showing one embodiment of an ink jet recording apparatus.

FIG. 5 is a longitudinal sectional view showing one embodiment of an ink cartridge.

FIG. 6 is a schematic perspective view showing another example of the configuration of the ink jet recording head.

FIG. 7 is a schematic explanatory view of a recording head to which four ink cartridges are attached.

FIG. 8 is a schematic explanatory view showing a configuration in which four recording heads are arranged on a carriage.

[Explanation of symbols]

 13: Head 14: Ink groove 15: Heating head 16: Protective film 17-1, 17-2: Electrode 18: Heating resistor layer 19: Heat storage layer 20: Substrate 21: Ink 22: Discharge orifice 23: Meniscus 24: Ink Drop 25: Recording medium 26: Multi-groove 27: Glass plate 40: Ink bag 42: Plug 44: Ink absorber 45: Ink cartridge 51: Paper feed unit 52: Paper feed roller 53: Paper discharge roller 61: Blade 62: Cap 63: Ink absorber 64: Discharge recovery unit 65: Recording head 66: Carriage 67: Guide shaft 68: Motor 69: Belt 70: Recording unit 71: Head unit 72: Atmospheric communication port 80: Ink channel 81: Orifice plate 82: diaphragm 83: piezoelectric element 84: substrate 85: discharge port 86, 87, 88, 89: recording head

Continued on front page F-term (reference) 2C056 FC02 2H086 BA55 BA60 4J039 BA04 BC03 BC19 BC41 BC50 BC51 BC52 BC61 BC66 BC77 BC79 BE01 CA03 CA06 EA15 EA16 EA17 EA44 GA24

Claims (8)

[Claims] Claims 1. A colorant, a liquid medium in which the colorant is dispersed or dissolved, and carbon black, and the content of the carbon black is 0.1 wt% or less. ink. 2. The method according to claim 1, wherein the content of the carbon black is 0.1.
The ink according to claim 1, which is less than 05 wt%. 3. The ink according to claim 1, wherein the colorant is a yellow dye or a yellow pigment. 4. The ink according to claim 1, wherein the colorant is a cyan dye or a cyan pigment. 5. The ink according to claim 1, wherein the colorant is a magenta dye or a magenta pigment. 6. The ink according to claim 1, wherein the carbon black is a self-dispersion type carbon black. 7. The ink according to claim 1, which is prepared for inkjet recording. 8. An ink jet recording apparatus of a type for discharging ink using thermal energy, wherein
An ink jet recording apparatus using the ink described in (1).