JP2003165934A - Ink for inkjet recording, recording unit, controlling method for seeding generation, inkjet recording method, ink cartridge, and inkjet recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controlling method for seeding generation for controlling seeding generation which may occur due to aluminum eluted in an ink, to prepare an ink without a twist, or the like, by an ink discharge even if alumina and metal aluminum are appropriately used in constituent materials of an inkjet recording apparatus, to provide the inkjet recording apparatus, a recording unit and an ink cartridge. <P>SOLUTION: An ink for inkjet wherein an elution amount of aluminum into the ink is not more than 0.3 ppm when immersing 100 g of alumina having 2.0 cm<SP>2</SP>/g of a specific surface area into 100 g of the ink at 60°C/24 h; an ink for inkjet recording wherein an elution amount of aluminum into the ink is not more than 10 ppm when immersing 20 g of metal aluminum having 4.5 cm<SP>2</SP>/g of a specific surface area into 100 g of the ink at 60°C/24 h; a recording unit; an ink cartridge; a recording method and an inkjet recording apparatus are provided. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet recording ink (recording liquid) suitable for an on-demand type inkjet printer such as a thermal jet system or a piezo system, a recording unit for an inkjet recording device, and an inkjet recording device. The present invention relates to a method for suppressing the generation of spots, which suppresses the generation of precipitates in the vicinity of a nozzle, an inkjet recording method using the above ink, an ink cartridge, and an inkjet recording apparatus.

[0002]

2. Description of the Related Art Conventionally, alumina, which is excellent in robustness and corrosion resistance, and metallic aluminum, which is excellent in thermal conductivity and electric conductivity, have been widely used as constituent materials for ink jet recording apparatuses. There is. However, in an ink jet recording apparatus having a structure in which members made of these materials come into contact with ink, it has been observed that ink ejection may be misaligned depending on the ink used.

[0003]

The inventors of the present invention have made repeated studies on this twist of ink ejection, and found that alumina is certainly excellent in robustness and corrosion resistance and is susceptible to corrosion. However, it has been found that there are cases where it is not perfect, although depending on the ink used, a small amount of aluminum ion or aluminate ion may elute from the alumina member, for example. Similarly, even when a member made of metallic aluminum is used, it may be eluted as aluminum ion or aluminate ion, for example, depending on the presence of acid or alkali contained in the ink.

When the concentration of aluminum ions, aluminate ions, or both of them in the ink exceeds a certain amount, the performance of the ink jet recording apparatus may be in the vicinity of the nozzle even if the performance as a component is not impaired. In the above, when water or volatile components in the ink evaporate, the ion balance or pH value in the ink changes, and the substance in the ink caused by aluminum precipitates to form a spot. It has been found that the existence of the ink causes the twist of the ink ejection.

Therefore, it is an object of the present invention to effectively suppress the generation of spots which are considered to be generated in the vicinity of the nozzles of the recording head due to the precipitation of aluminum which is eluted from the member into the ink during ink jet recording. An object of the present invention is to provide a method for suppressing the occurrence of spots. or,
An object of the present invention is to provide an ink for inkjet recording, a recording unit, an inkjet recording method, an ink cartridge, and an inkjet recording apparatus, which can effectively prevent the occurrence of ink ejection deviation by suppressing the generation of the above-mentioned spots. To do. Further, the object of the present invention is to
An inkjet recording ink, a recording unit, an inkjet recording method, and an ink cartridge capable of forming an image with excellent image quality by enabling appropriate use of a member composed of alumina or metallic aluminum suitable for an inkjet recording apparatus And an inkjet recording apparatus.

[0006]

The above objects can be achieved by the present invention described below. That is, according to the present invention, the ink 10
Alumina 100 having a specific surface area of 2.0 cm ² / g in 0 g
In the case of being immersed at 60 ° C. for 24 hours, the elution amount of aluminum in the ink is 0.3 pp.
It is an inkjet recording ink of m or less.

Another form of the ink according to the present invention that can achieve the above object is 2.0 cm in 100 g of the ink.
100 g of alumina having a specific surface area of ² / g is added to 60 ° C / 170
This is an inkjet recording ink in which the amount of aluminum eluted into the ink is 0.5 ppm or less when immersed under the condition of time. Another form of the ink according to the present invention that can achieve the above object is the ink 10.
When 20 g of metallic aluminum having a specific surface area of 4.5 cm ² / g in 0 g was immersed at 60 ° C. for 24 hours, the amount of aluminum eluted into the ink was 10
The inkjet recording ink has a ppm or less.

Further, a more preferable embodiment of the ink according to the present invention which can achieve the above object is that in any one of the inks mentioned above, the total concentration of alkali metal contained in the ink is The inkjet recording ink is limited to less than 120 mmol / kg.
Further, a more preferred embodiment of the ink according to the present invention that can achieve the above-mentioned object is, in any of the above-mentioned ink configurations, an alkali derived from a hydroxide of an alkali metal contained in the ink. Total metal concentration is 45m
It is an inkjet recording ink that is limited to less than mol / kg. Further, another embodiment of the present invention is an ink jet recording method characterized by using the ink having any one of the constitutions described above.

Furthermore, another embodiment of the present invention for achieving the above object is a recording unit having a head portion for ejecting ink as ink droplets, which is used in an ink jet recording apparatus. , An ink containing alumina or metallic aluminum as a constituent material, and as ink ejected from the head,
A recording unit characterized by combining inks having any of the above-mentioned configurations, an ink cartridge using the unit, and an inkjet recording apparatus.

Furthermore, another embodiment of the present invention for achieving the above object is to eject ink in a method for suppressing the generation of seeds, which suppresses the generation of precipitates in the vicinity of the nozzle of the head of an ink jet recording apparatus. On the head of
A method for suppressing the generation of lumps is characterized in that a head containing alumina or metallic aluminum as a constituent material is used, and the head is used in combination with an ink having any one of the above-mentioned structures.

As a result of intensive studies to solve the above-mentioned problems of the prior art, the present inventors have found that the elution of alumina or aluminum into the ink itself can be suppressed to a level at which no spots occur. It was That is, as an ink used for inkjet recording, by using an ink having an aluminum elution amount of a specific amount or less in an aluminum elution test performed under each of the above-mentioned conditions, the ink is used as a constituent material of an inkjet recording device, particularly as a head. Even when alumina or metallic aluminum is used, they have found that the above-mentioned adverse effects can be effectively suppressed, and have reached the present invention.

That is, when the inks having the above-mentioned constitutions are adopted for ink jet recording, alumina excellent in fastness and corrosion resistance, and metallic aluminum excellent in heat conductivity, electric conductivity, etc. Can be freely used as a constituent material of a recording head for inkjet recording. Further, according to the study by the present inventors, the total concentration of alkali metals contained in the ink having the above-mentioned constitution is 12
If the amount is less than 0 mmol / kg, or if the total concentration of the alkali metals derived from the hydroxide of the alkali metal contained in the ink is less than 45 mmol / kg, the content of the highly corrosive alkali metal is small. It is possible to effectively suppress the dissolution of alumina or metallic aluminum used as a constituent material of the recording head for recording in the ink, and to effectively prevent the deposition of a substance caused by aluminum eluted in the ink near the nozzle, which is eluted in the ink. Found out. Further, as a result of the above, it has been found that the occurrence of ink ejection deviation in inkjet recording can be effectively prevented.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail with reference to preferred embodiments. (Ink) The ink for inkjet recording according to the first embodiment of the present invention is Ink 10
Alumina 100 having a specific surface area of 2.0 cm ² / g in 0 g
In the case of being immersed at 60 ° C. for 24 hours, the elution amount of aluminum in the ink is 0.3 pp.
It is characterized by being m or less. The ink for inkjet recording of the second embodiment of the present invention comprises 60 g of 100 g of alumina having a specific surface area of 2.0 cm ² / g in 100 g of ink.
When immersed in the condition of ℃ / 170 hours,
The amount of aluminum eluted into the ink is 0.5 ppm or less. The ink for inkjet recording according to the third aspect of the present invention has 4.5c in 100g of the ink.
20 g of metallic aluminum having a specific surface area of m ² / g at 60 ° C.
When immersed under the condition of / 24 hours, the amount of aluminum eluted into the ink is 10 ppm or less. Furthermore, in addition to the above configuration, the total concentration of alkali metals contained in the ink is 120 mmo.
In the case of an ink of less than 1 / kg, or an ink in which the total concentration of alkali metals derived from hydroxides of alkali metals contained in the ink is less than 45 mmol / kg,
The effects of the present invention described above are particularly remarkably obtained.

As a method of immersing alumina or metallic aluminum having a specific surface area in the ink to examine the amount of aluminum eluted into the ink, the amount of aluminum in the ink before and after the immersion is determined by ICP (plasma emission analysis). ) Is used for the quantification to easily perform the measurement.

The ink jet recording ink of the present invention comprises
The ink components and the like are not particularly limited as long as they satisfy the above requirements, but since they have to be established as inks for inkjet recording, it is of course that they have ejection characteristics from nozzles, image forming characteristics, and the like. ,is necessary. When forming the ink jet recording ink of the present invention, from such a viewpoint, a coloring material,
A medium (solvent), additives, etc. may be appropriately selected and used.

(Alkali metal in ink) In the present invention, the alkali metal contained in the ink specifically means lithium, sodium, potassium, rubidium and cesium. Francium, also an alkali metal, is a radioactive element and is rarely found in nature, so its use is practically difficult. The reason why the alkali metal is contained in the ink is considered to be addition as a pH adjusting agent, addition as a counter ion such as a coloring material, and impurities contained in other ink components. The alkali metal contained in the ink in the invention includes inclusion in all these forms. In the ink jet recording ink of the present invention, the total amount of the alkali metal as described above in the ink is 120 mm.
It is preferable to limit it to less than ol / kg.
The total concentration of alkali metals in the ink is ICP
(Plasma emission analysis) allows easy quantification.

(Alkali Metal Hydroxide) In the ink jet recording ink of the present invention, the total concentration of the alkali metal derived from the alkali metal hydroxide is 45 mmol.
It is also a preferable mode to limit the amount to less than 1 kg. The alkali metal hydroxide is the above-mentioned alkali metal hydroxide, specifically, lithium hydroxide,
Examples thereof include sodium hydroxide and potassium hydroxide.
In this case, the total concentration of alkali metals is
(Plasma emission analysis) allows easy quantification.

As described above, the ink composition for ink jet recording of the present invention is not particularly limited as long as it satisfies the above-mentioned constitutional requirements, but the ink composition is generally used for forming the ink below. A coloring material and a solvent used conventionally, and an additive used if necessary will be described. (Coloring Material) As the coloring material, any dye or pigment can be used. Specific examples of the dye will be illustrated for each color tone of the ink. Of course, the dyes that can be used in the present invention are not limited to the dyes listed below.

(Coloring Material for Yellow) Examples of dyes for yellow include C.I. I. Direct Yellow: 8, 11, 12, 27,
28, 33, 39, 44, 50, 58, 85, 86, 8
7, 88, 89, 98, 100, 110, 132; C.I. I. Acid Yellow: 1, 3, 7, 11, 17,
23, 25, 29, 36, 38, 40, 42, 44, 7
6, 98, 99; C.I. I. Reactive Yellow: 2, 3, 17, 25,
37, 42; C.I. I. Food Yellow: 3 and the like.

(Coloring Material for Red) Examples of dyes for red include C.I. I. Direct Red: 2, 4, 9, 11, 20,
23, 24, 31, 39, 46, 62, 75, 79, 8
0, 83, 89, 95, 197, 201, 218, 22
0, 224, 225, 226, 227, 228, 22
9, 230; C.I. I. Acid Red: 6, 8, 9, 13, 14, 1
8, 26, 27, 32, 35, 42, 51, 52, 8
0, 83, 87, 89, 92, 106, 114, 11
5, 133, 134, 145, 158, 198, 24
9, 265, 289; C.I. I. Reactive Red: 7, 12, 13, 15,
17, 20, 23, 24, 31, 42, 45, 46, 5
9; C.I. I. Hood Red: 87, 92, 94; C.I. I. Direct violet: 107 and the like.

(Coloring Material for Blue) Examples of dyes for blue include C.I. I. Direct Blue: 1, 15, 22, 25, 4
1, 76, 77, 80, 86, 90, 98, 106, 1
08, 120, 158, 163, 168, 199, 22
6; C.I. I. Acid Blue: 1, 7, 9, 15, 22, 2
3, 25, 29, 40, 43, 59, 62, 74, 7
8, 80, 90, 100, 102, 104, 117, 1
27, 138, 158, 161; C.I. I. Reactive blue: 4, 5, 7, 13, 1
4, 15, 18, 19, 21, 26, 27, 29, 3
2, 38, 40, 44, 100 and the like.

(Coloring Material for Black) Examples of dyes for black include C.I. I. Direct Black: 17, 19, 22, 3
1, 32, 51, 62, 71, 74, 112, 113,
154, 168, 195; C.I. I. Acid Black: 2, 48, 51, 52, 1
C. 10, 115, 156; I. Food Black: 1, 2 and the like.

Further, the pigment is not particularly limited, and in addition to a usual pigment which is stably dispersed in a solvent by using a dispersant, a pigment which can be dispersed in a solvent without using a dispersant is particularly used. A self-dispersion pigment in which the surface of the particle is modified is also included. The content of the coloring materials such as the dyes and pigments mentioned above in the ink is not particularly limited.

(Medium) Next, a medium that can be used for forming the ink according to the present invention will be described. The ink according to the present invention is usually formed by dissolving or dispersing the above-mentioned coloring materials in an aqueous medium. Examples of the aqueous medium include water and a mixed solvent of water and a water-soluble organic solvent. In the present invention, it is particularly preferable to use a mixed solvent of water and a water-soluble organic solvent.
As the water-soluble organic solvent, one having an effect of preventing ink drying is particularly preferable. It is preferable to use deionized water as the water.

Examples of the water-soluble organic solvent include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol,
C1-C4 alkyl alcohols such as sec-butyl alcohol and tert-butyl alcohol; amides such as dimethylformamide and dimethylacetamide; ketones and keto alcohols such as acetone, methyl ethyl ketone, methyl isobutyl ketone and diacetone alcohol; Ethers such as tetrahydrofuran and dioxane; polyalkylene glycols such as polyethylene glycol and polypropylene glycol; ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, Polyethylenes in which the alkylene group such as diethylene glycol contains 2 to 6 carbon atoms; polyethylene glycol monomethyl ether acetate, etc. Lower alkyl ether acetates; glycerin; lower alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol methyl (or ethyl) ether, triethylene glycol monomethyl (or ethyl) ether; trimethylolpropane, trimethylol Polyhydric alcohols such as ethane; N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, urea and derivatives thereof and the like can be mentioned.

The above water-soluble organic solvents can be used alone or as a mixture. The amount of the water-soluble organic solvent contained in the ink according to the present invention is not particularly limited, but is 3 to 50 with respect to the total weight of the ink.
It is preferable to set it in the range of mass%. Further, the amount of water in the ink is preferably in the range of 50 to 95 mass% with respect to the total weight of the ink.

(Additive) In addition, a surfactant, an antifoaming agent, and
Additives such as antiseptics, antifungal agents, pH adjusters, and antioxidants can be added.

(Recording Unit for Inkjet Recording Device) Further, the recording unit of the present invention is used for an inkjet recording device, and the head for ejecting ink as ink droplets is made of alumina or metallic aluminum. It is characterized by comprising a head made of a material, and as the ink ejected from the head, the ink according to the present invention described above is used in combination.

Specifically, when the head for ejecting the ink of the recording unit used in the ink jet recording apparatus is made of alumina or metallic aluminum as a constituent material, the ink jet recording used in combination therewith. Ink 100
100 g of alumina having a specific surface area of 2.0 cm ² / g in g
When the ink is immersed at 60 ° C for 24 hours, the elution amount of aluminum in the ink is 0.3 ppm.
The following ink, or 2.0 cm in 100 g of ink
100 g of alumina having a specific surface area of ² / g is added to 60 ° C / 170
When immersed under the condition of time, an ink having an aluminum elution amount of 0.5 ppm or less in the ink, or 20 g of metallic aluminum having a specific surface area of 4.5 cm ² / g in 100 g of the ink at 60 ° C. / It is characterized by using an ink in which the amount of aluminum eluted into the ink is 10 ppm or less when immersed for 24 hours. More preferably, the inkjet recording ink having any one of the above configurations has a total concentration of alkali metals contained in the ink of 120 mmol / kg.
And the total concentration of the alkali metal derived from the hydroxide of the alkali metal contained in the ink is 4 or less.
Use ink that is less than 5 mmol / kg.

By constructing the recording unit as described above, it is possible to freely use alumina, which is excellent in robustness and corrosion resistance, and metallic aluminum, which is excellent in thermal conductivity and electrical conductivity, as the constituent material. As a result, a recording unit having a high-performance head and effectively suppressing generation of spots due to deposition of aluminum in the vicinity of the nozzle of the head and having no deviation in ink ejection. be able to. Further, in the above-mentioned configuration, naturally, a constituent member, such as an ink flow path until the ink is ejected from the ink containing portion, which is in direct contact with the ink, is made of alumina or metallic aluminum. Although it is particularly effective in the case of a recording unit, even if the member made of alumina or metallic aluminum is not the component directly in contact with the ink, alumina or metallic aluminum is converted into aluminum through another member in direct contact with the ink. The effect is also seen in the recording unit in which the ink may be dissolved in the ink.

(Method for Suppressing Occurrence of Spots near Nozzles in Inkjet Recording) The method for suppressing stagnation in the present invention is caused by dissolution of alumina or metallic aluminum forming a recording head of an inkjet recording apparatus into ink. The present invention is a method for suppressing the generation of spots in the vicinity of the nozzles of a recording head, which brings about an effect of being able to effectively prevent the occurrence of ink ejection deviation in inkjet recording.

The method for suppressing the generation of seeds of the present invention is a method for suppressing the generation of deposits that occur in the vicinity of the nozzles of the head of an ink jet recording apparatus, and the head for ejecting ink is made of alumina or metallic aluminum as a constituent material. When using a head to
The ink according to the present invention described above is used in combination.

Specifically, when the head for ejecting the ink of the recording unit used in the ink jet recording apparatus is made of alumina or metallic aluminum as a constituent material, the ink jet recording used in combination therewith. Ink 100
100 g of alumina having a specific surface area of 2.0 cm ² / g in g
When the ink is immersed at 60 ° C for 24 hours, the elution amount of aluminum in the ink is 0.3 ppm.
The following ink, or 2.0 cm in 100 g of ink
100 g of alumina having a specific surface area of ² / g is added to 60 ° C / 170
When immersed under the condition of time, an ink having an aluminum elution amount of 0.5 ppm or less in the ink, or 20 g of metallic aluminum having a specific surface area of 4.5 cm ² / g in 100 g of the ink at 60 ° C. / It is characterized by using an ink in which the amount of aluminum eluted into the ink is 10 ppm or less when immersed for 24 hours. More preferably, the inkjet recording ink having any one of the above configurations has a total concentration of alkali metals contained in the ink of 120 mmol / kg.
And the total concentration of the alkali metal derived from the hydroxide of the alkali metal contained in the ink is 4 or less.
Use ink that is less than 5 mmol / kg.

(Mechanism) Although the details are unknown, aluminum is eluted from the alumina member or the metallic aluminum member into the ink by the following mechanism, and the substances caused by the dissolved aluminum are generated in the vicinity of the nozzle or the like as described below. It is thought that it will be deposited on. First, alumina and metallic aluminum are dissolved in the ink as hydrated aluminum ions Al ³⁺ and aluminate ions AlO ²⁻ mainly by the chemical reactions shown in the following reaction formulas 1 to 6.

<Reaction Formula 1> Al ₂ O ₃ + 2MOH → 2AlO ₂ ⁻ + 2M ⁺ + H ₂ O <Reaction Formula 2> Al ₂ O ₃ + 6HX → 2Al ³⁺ + 6X ⁻ + 3H ₂ O <Reaction Formula 3> Al ₂ O ₃ + 3H ₂ SO ₄ → 2Al ³⁺ + 3SO ₄ ^2- + 3H ₂ O <Reaction formula 4> 2Al + 2MOH + 2H ₂ O → 2AlO ₂ ⁻ + 2M ⁺ + 3H ₂ <Reaction formula 5> 2Al + 6HX → 2Al ³⁺ + 6X ⁻ + 3H ₂ <Reaction formula 6> 2Al + 3H ₂ SO ₄ → 2Al ³⁺ + 3SO ₄ ^2- + 3H ₂ (However, M in the above reaction formula represents an alkali metal, X
Represents halogen or NO ₃ . )

An ink containing a strong acid or a strong base as a component,
When it comes into contact with alumina or metallic aluminum used as a constituent material of an ink jet recording apparatus directly or through another member, the hydrated aluminum ions A are contained in the ink by the chemical reactions shown in the above reaction formulas 1 to 6.
l ³⁺ and aluminate ion AlO ₂ ⁻ are eluted. Then, in the vicinity of the nozzle of the ink jet recording apparatus, changes in ion balance and pH value in the ink due to factors such as evaporation of water and volatile components in the ink occur, and hydrated aluminum ions Al ³⁺ and Aluminate ion AlO ₂ ^- is deposited in the vicinity of the nozzle as aluminum hydroxide Al (OH) ₃ which is almost insoluble in water and becomes a lump,
It is considered that the presence of these spots induces a twist in ink ejection.

[0037] These hydrated aluminum ions Al ³⁺ or aluminate ion AlO ₂ ^- from aluminum hydroxide A
An example of the chemical reaction that l (OH) ₃ produces is represented by the following reaction formulas 7 and 8.

<Reaction Formula 7> AlO ₂ ⁻ + H ⁺ + H ₂ O → Al (OH) ₃ <Reaction Formula 8> Al ³⁺ + 3OH ⁻ → Al (OH) ₃

The degree of progress of the chemical reaction shown in the above reaction formulas 1 to 6 in which aluminum is eluted as hydrated aluminum ion Al ³⁺ or aluminate ion AlO ₂ ⁻ from alumina or metallic aluminum is included in the ink. There is a correlation with the concentrations of components such as strong acids and strong bases, and basically, the higher the concentration of strong acids and strong bases, the greater the elution amount of aluminum.

According to the study by the present inventors, in particular, the degree of progress of the chemical reactions shown in the above reaction formulas 1 and 4 is determined by the total concentration of the alkali metal contained in the ink, and further, It was found that the total concentration of the alkali metal derived from the hydroxide of the alkali metal contained in the ink was greatly affected. Further, if the total concentration of the alkali metal contained in the ink and the total concentration of the alkali metal derived from the hydroxide of the alkali metal are limited to less than the predetermined concentration described above, the elution of aluminum into the ink It was found that the effect of suppressing is expected.

[0041] Further, the aluminate ion AlO ₂ ^- solubility product ^{_{[AlO 2 -] [H +}} ] and the solubility product of the hydrated aluminum ions ^{Al 3+ [Al 3+] [OH} -] be considered from ^3, The lower the concentration of aluminum eluted into the ink, the narrower the pH range in which the dissolved aluminum begins to precipitate as aluminum hydroxide Al (OH) ₃ . That is, the smaller the elution amount of aluminum in the ink is, the more the allowable range until the spots of aluminum hydroxide Al (OH) ₃ that causes the deviation of ink ejection is deposited in the vicinity of the nozzle of the inkjet recording apparatus. It is expected to become wider. Furthermore,
It is considered that the smaller the elution amount of aluminum in the ink is, the smaller the absolute amount of aluminum hydroxide Al (OH) ₃ deposited in the vicinity of the nozzle is.

(Inkjet recording apparatus etc.) Next, an example of the inkjet recording apparatus of the present invention to which the recording unit of the present invention is applied will be described below. First, FIG. 1 and FIG. 2 show an example of a head configuration which is a main part of an inkjet recording apparatus using thermal energy. Figure 1
FIG. 3 is a cross-sectional view of the head 13 taken along the ink flow path shown in FIG.
[Fig. 2] is a sectional view taken along line AB of Fig. 1.

The head 13 is obtained by bonding a glass, ceramic, alumina, silicon or plastic plate or the like having a flow passage (nozzle) 14 for passing ink to the heating element substrate 15. The heating element substrate 15 is made of silicon oxide,
Protective layer 1 made of silicon nitride, silicon carbide, etc.
6, electrodes 17-1 and 17-2 formed of aluminum, gold, aluminum-copper alloy, etc., HfB ₂ , TaN,
Heating resistor layer 1 formed of a high melting point material such as TaAl
8, a heat storage layer 19 made of thermally oxidized silicon, alumina (aluminum oxide) or the like, and a substrate 20 made of a material having a good heat dissipation property such as silicon, aluminum or aluminum nitride. In the present invention, for example, when the flow path (nozzle) 14 for passing the ink and the heat storage layer 19 are made of alumina (aluminum oxide) which is excellent in robustness and corrosion resistance, the electrode 17 and the substrate 20 have thermal conductivity. And when it is made of metallic aluminum having excellent electrical conductivity, a particularly remarkable effect is obtained.

Electrodes 17-1 and 17- of the head 13
When a pulsed electric signal is applied to 2, the area indicated by n on the heating element substrate 15 rapidly generates heat, bubbles are generated in the ink 21 in contact with this surface, and the meniscus 23 is projected by the pressure. , The ink 21 is ejected through the nozzle 14 of the head, and the ink droplet 24 is ejected from the ejection orifice 22.
And fly toward the recording material 25. In Figure 3,
FIG. 2 is an external view of an example of a multi-head in which a large number of heads shown in FIG. 1 are arranged. This multi-head has a multi-nozzle 26
It is made by bonding a glass plate 27 having a heating element and a heating head 28 similar to that described in FIG.

FIG. 4 shows an example of an ink jet recording apparatus incorporating this head. In FIG. 4, reference numeral 61 denotes a blade as a wiping member, one end of which is held and fixed by a blade holding member, and has a form of a cantilever. The blade 61 is arranged at a position adjacent to the recording area by the recording head 65, and in the case of this example,
The recording head 65 is held in a protruding form in the moving path.

Reference numeral 62 denotes a cap on the projecting opening surface of the recording head 65, which is arranged at the home position adjacent to the blade 61, moves in a direction perpendicular to the moving direction of the recording head 65, and contacts the ink ejection opening surface. It is provided with a structure for contacting and capping. Further, 63 is an ink absorber provided adjacent to the blade 61, and like the blade 61, is held in a form protruding in the moving path of the recording head 65. The blade 61, the cap 62, and the ink absorber 63 constitute an ejection recovery unit 64, and the blade 61 and the ink absorber 63 remove water and dust on the ejection port surface.

Reference numeral 65 has a discharge energy generating means,
A recording head 66 for performing recording by ejecting ink onto a recording material facing the ejection port surface provided with the ejection ports, 66 is the recording head 6
5 is a carriage for carrying the recording head 65 and moving the recording head 65. The carriage 66 slidably engages with the guide shaft 67, and a part of the carriage 66 is connected (not shown) to a belt 69 driven by a motor 68. As a result, the carriage 66 can move along the guide shaft 67, and the recording area of the recording head 65 and its adjacent area can move.

Reference numeral 51 is a paper feeding portion for inserting a recording material, and 52 is a paper feeding roller driven by a motor (not shown). With these configurations, the recording material is fed to the position facing the ejection port surface of the recording head 65, and is ejected to the ejection portion provided with the ejection roller 53 as the recording progresses. With the above configuration, when the recording head 65 finishes recording and returns to the home position, the cap 62 of the ejection recovery unit 64 is retracted from the movement path of the recording head 65, but the blade 61 is projected in the movement path. . As a result, the ejection port of the recording head 65 is wiped.

When the cap 62 comes into contact with the ejection surface of the recording head 65 to perform capping, the cap 62 moves so as to project into the moving 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 the positions at the time of wiping described above. As a result, the ejection opening surface of the recording head 65 is wiped even during this movement. The above-mentioned movement of the recording head to the home position is performed not only at the end of recording and at the time of ejection recovery, but also at a predetermined interval while the recording head moves in the recording area to the home position adjacent to the recording area. Then
The wiping is performed along with this movement.

FIG. 5 is a diagram showing an example of an ink cartridge in which the ink is supplied to the recording head through an ink supply member, for example, a tube. 40 here
Is an ink containing portion containing 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. Reference numeral 44 is an ink absorber that receives waste ink.
As the ink container, it is preferable that the surface in contact with the ink is made of polyolefin, especially polyethylene.

The ink jet recording apparatus of the present invention is not limited to the one in which the recording head and the ink cartridge are separately provided as described above, and a unit in which they are integrated as shown in FIG. 6 is also a preferable form. is there. In FIG. 6, 70
Is a recording unit, in which an ink containing portion containing ink, for example, an ink absorber is stored,
The ink in the ink absorber is ejected as ink droplets from the head portion 71 having a plurality of orifices. As a material for the ink absorber, it is preferable to use polyurethane, polyolefin fiber or the like.
Further, the structure may be such that the ink containing portion is an ink bag having a spring or the like inside, without using the ink absorber. 72
Is an atmosphere communication port for communicating the inside of the cartridge with the atmosphere. The recording unit 70 is used in place of the recording head 65 shown in FIG. 4, and is detachable from the carriage 66.

[0052]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. In the following description, “part” and “%” are based on mass unless otherwise specified.

[Example 1] ・ Glycerin 10 parts ・ Diethylene glycol 7 parts ・ Urea 10 parts ・ Acetylene glycol ethylene oxide adduct (Product name: acetylenol EH) Part 1 -C. I. Direct Violet 107 2nd -C. I. Acid Red 289 2nd ・ Water 68 parts

[Example 2] ・ Glycerin 10 parts ・ Diethylene glycol 7 parts ・ Urea 10 parts ・ Acetylene glycol ethylene oxide adduct (Product name: acetylenol EH) Part 1 ・ 4N-lithium hydroxide 1 part -C. I. Direct Violet 107 2nd -C. I. Acid Red 289 2nd ・ 67 parts of water

[Embodiment 3] ・ Glycerin 10 parts ・ Diethylene glycol 7 parts ・ Urea 10 parts ・ Acetylene glycol ethylene oxide adduct (Product name: acetylenol EH) Part 1 ・ 4N-lithium hydroxide 0.6 part -C. I. Direct Blue 199 4 copies ・ Water 67.4 parts

[Example 4] ・ Glycerin 10 parts ・ Diethylene glycol 7 parts ・ Urea 10 parts ・ Acetylene glycol ethylene oxide adduct (Product name: acetylenol EH) Part 1 -C. I. Direct Yellow 132 3.5 copies ・ Water 68.5 parts

[Example 5] ・ Glycerin 10 parts ・ Diethylene glycol 5 parts ・ 2-Pyrrolidone 3 parts ・ Urea 10 parts ・ Acetylene glycol ethylene oxide adduct (Product name: acetylenol EH) Part 1 -C. I. Direct Yellow 132 3.5 copies ・ Water 67.5 parts

Comparative Example 1 ・ Glycerin 10 parts ・ Diethylene glycol 7 parts ・ Urea 10 parts ・ Acetylene glycol ethylene oxide adduct (Product name: acetylenol EH) Part 1 ・ 4N-lithium hydroxide 1.5 parts -C. I. Direct Violet 107 2nd -C. I. Acid Red 289 2nd ・ Water 66.5 copies

Comparative Example 2 ・ Glycerin 10 parts ・ Diethylene glycol 7 parts ・ Urea 10 parts ・ Acetylene glycol ethylene oxide adduct (Product name: acetylenol EH) Part 1 ・ 4N-lithium hydroxide 2.5 parts -C. I. Direct Violet 107 2nd -C. I. Acid Red 289 2nd ・ Water 65.5 parts

Comparative Example 3 ・ Glycerin 10 parts ・ Diethylene glycol 7 parts ・ Urea 10 parts ・ Acetylene glycol ethylene oxide adduct (Product name: acetylenol EH) Part 1 ・ 4N-lithium hydroxide 1.2 parts -C. I. Direct Blue 199 4 copies ・ Water 66.8 parts

Table 1 shows Example 1 having each composition described above.
~ 5 and each ink of Comparative Examples 1 to 3, "ink 1
Alumina 10 having a specific surface area of 2.0 cm ² / g in 00 g
Aluminum elution amount in ink when 0 g was immersed under the condition of 60 ° C./24 hours ”(displayed as Al elution amount <alumina immersion 60 ° C./24 hours>),“ 2.0 cm in 100 g of ink ” Elution amount of aluminum in ink when 100 g of alumina having a specific surface area of ² / g is immersed under the condition of 60 ° C./170 hours ”
(Indicated as Al elution amount <alumina immersion 60 ° C./170 hours>), “When 20 g of metallic aluminum having a specific surface area of 4.5 cm ² / g in 100 g of ink is immersed under the condition of 60 ° C./24 hours, Elution amount of aluminum in ink "(Al elution amount <aluminum immersion 60 ° C
/ 24 hours>). The unit of the elution amount of aluminum in the ink is ppm. or,
At the same time, in each of the inks of Examples and Comparative Examples, “total concentration of alkali metal contained in ink” (indicated as amount of alkali metal), “of alkali metal derived from hydroxide of alkali metal contained in ink” The "total concentration" (indicated as the amount of alkali metal hydroxide) was also measured and is also shown in Table 1. The unit of the amount of alkali metal and the amount of alkali metal hydroxide is mmol / kg.

[0062]

[Table 1]

(Evaluation method) A modified ink jet printer BJS600 manufactured by Canon was filled with the inks of Examples 1 to 5 and Comparative Examples 1 to 3 and allowed to stand for 1 month in an environment of 30 ° C / 10% RH. After that, each ink was ejected, and the occurrence of ejection deviation was evaluated. A constituent member made of alumina is used as a constituent member of the head portion for ejecting ink of the printer used for the evaluation. The evaluation pattern is printed on a special coated paper (trade name HR-101, manufactured by Canon) with a thin line drawn at the same pitch.
It was evaluated visually. If the landing point of the droplet (ink droplet) is at the normal position, it is recognized by the human eye as a very uniform halftone pattern. If the landing point deviates from the normal position, irregularities and streaks will appear.

(Evaluation Results) No unevenness or streaks were found in the evaluation patterns printed using the inks of Examples 1 to 5, and it was confirmed that the ink ejection did not occur. On the other hand, in the evaluation patterns printed using the inks of Comparative Examples 1 to 3, unevenness and streaks were present, and deviation of ink ejection occurred.

[0065]

As described above, according to the present invention,
By limiting the amount of aluminum elution into the ink under a specific elution condition to a specific amount or less, it is possible to effectively suppress the generation of spots that are considered to be caused by the aluminum eluted in the ink. A method for suppressing the occurrence of spots is provided. Further, according to the present invention, even when a member made of alumina or metallic aluminum having excellent performance is appropriately used as a constituent material of an ink jet recording apparatus, the generation of spots that may cause twisting of ink ejection is suppressed, which is a harmful effect. An inkjet recording ink, an inkjet recording device, a recording unit, and an ink cartridge that do not cause the above are provided.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a head of an inkjet recording apparatus.

FIG. 2 is a sectional view taken along the line AB of FIG.

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

FIG. 4 is a schematic perspective view showing an embodiment of an inkjet recording apparatus.

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

FIG. 6 is a perspective view showing an example of a recording unit.

[Explanation of symbols]

13: Head 14: flow path (nozzle) 15: Heating element substrate 16: Protective layer 17-1, 17-2: Electrodes 18: Heating resistor layer 19: Heat storage layer 20: substrate 21: Ink 22: Discharge orifice 23: Meniscus 24: Ink droplet 25: Recording material 26: Multi nozzle 27: Glass plate 28: Heating head 40: Ink bag 42: Stopper 44: Ink absorber 45: Ink cartridge 51: Paper feed section 52: Paper feed roller 53: Paper ejection 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 part 72: Air communication port

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2C056 EA21 FA03 FC02 HA17                 2H086 BA02 BA60 BA62                 4J039 GA24

Claims (14)

[Claims] 1. When 100 g of alumina having a specific surface area of 2.0 cm ² / g is immersed in 100 g of ink under the condition of 60 ° C./24 hours, the elution amount of aluminum in the ink is 0.3 ppm or less. An ink for ink jet recording characterized by being present. 2. When 100 g of alumina having a specific surface area of 2.0 cm ² / g is soaked in 100 g of ink under the condition of 60 ° C./170 hours, the elution amount of aluminum in the ink is 0.5 ppm or less. The inkjet recording ink according to claim 1. 3. The amount of aluminum eluted into the ink is 10 ppm or less when 20 g of metallic aluminum having a specific surface area of 4.5 cm ² / g is immersed in 100 g of the ink under the condition of 60 ° C./24 hours. An inkjet recording ink characterized by the above. 4. The total concentration of alkali metals contained in the ink is less than 120 mmol / kg.
Ink for inkjet recording according to any one of 1. 5. The total concentration of alkali metal derived from the hydroxide of alkali metal contained in the ink is 45 mmo.
The inkjet recording ink according to any one of claims 1 to 4, which is less than 1 / kg. 6. Used in an ink jet recording apparatus,
A recording unit having a head portion for ejecting ink as ink droplets, wherein the head comprises a head made of alumina as a constituent material, and the ink ejected from the head is any one of claims 1 to 5. A recording unit comprising a combination of the inks according to item 1. 7. Used in an ink jet recording apparatus,
A recording unit having a head portion for ejecting ink as ink droplets, wherein the head comprises a head containing metal aluminum as a constituent material, and the ink ejected from the head is any one of claims 1 to 5. A recording unit comprising a combination of the inks according to item 1. 8. A method for suppressing the generation of deposits, which suppresses the generation of deposits in the vicinity of nozzles of a head of an ink jet recording apparatus, wherein a head containing alumina as a constituent material is used as the head for ejecting ink. On the other hand, a method for suppressing the generation of spots, which comprises using the ink according to any one of claims 1 to 5 in combination. 9. A method for suppressing the generation of deposits, which suppresses the generation of deposits in the vicinity of a nozzle of a head of an ink jet recording apparatus, wherein a head containing metallic aluminum as a constituent material is used as a head for ejecting ink, A method for suppressing generation of spots, which comprises using the ink according to claim 1 in combination with a head. 10. An ink jet recording method, wherein energy is applied to ink to cause the ink to fly to record on a recording material, wherein the ink is the ink according to any one of claims 1 to 5. And an inkjet recording method. 11. The ink jet recording method according to claim 10, wherein the energy is heat energy. 12. An ink cartridge comprising an ink containing portion containing ink and a recording unit having a head portion for ejecting ink as ink droplets, wherein the recording unit is the recording according to claim 6 or 7. An ink cartridge characterized by being a unit. 13. An ink jet recording apparatus comprising: an ink containing portion containing ink; and a recording unit having a head portion for ejecting the ink as ink droplets, wherein the recording unit is according to claim 6 or 7. Inkjet recording apparatus, which is a recording unit of. 14. An ink jet recording apparatus comprising an ink cartridge having an ink containing portion containing ink and a head portion for ejecting the ink as ink droplets, wherein the ink cartridge is the ink according to claim 12. An inkjet recording device characterized by being a cartridge.