JPH08120204A - Ink, ink jet recording method using same and equipment using the ink - Google Patents

Abstract

PURPOSE: To improve prevention of clogging, recording stability and storage stability by incorporating a specific compound, a urea, a coloring material and water. CONSTITUTION: This ink is prepared by dissolving 0.05-20wt.% at least one compound selected from compounds of formula I [R<1> , R<2> are each H, alkyl, benzyl, -CH2 CHOH, -CH2 (OH)CH3 ; R<3> , R<4> are each H, methyl; n>=1], compounds of formula II (R<1> is R<1> ; R<2> -R<5> are each H, methyl; n, m are each an integer satisfying m+n>=1), and compounds of formula III (R<1> -R<6> are each H, methyl; m, n, p are each an integer satisfying m+n>=1 and p>=1), 0.5-20wt.% urea and 0.1-15wt.% coloring agent in 50-98wt.% water so that the weight ratio of the compound(s) of formulae I-III to the urea may become 1:1-1:15, and adjusting the pH at 7-10.5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink for ink jet recording, an ink jet recording method using the ink, and devices using the ink, and more particularly, to an ink eye in a recording head portion of an ink jet recording apparatus. It has excellent anti-clogging properties and recording stability when recording by intermittent ejection, and when images are formed, it does not cause bronzing on plain paper, and it is possible to obtain images with good character quality. The present invention also relates to an ink having excellent storage stability in the case of performing, and an inkjet recording method and devices using the ink.

[0002]

2. Description of the Related Art Conventionally, when an aqueous ink is used as an ink for inkjet recording, problems such as clogging of nozzles due to evaporation of water from the recording head have occurred. On the other hand, various clogging prevention methods have been proposed. For example, it is common practice to add urea, urea derivatives, thiourea and thiourea derivatives to the ink (JP-A-57-74372 and JP-A-56-44).
88, JP-A-03-234775, JP-A-04-85375, JP-A-04-332777, etc.). However, in the ink containing a dye, especially a poorly water-soluble dye having a carboxyl group, the phenomenon that the gloss of the printed matter increases and black appears golden due to the reflection of light (bronze phenomenon) is urea. It was found to be accelerated by the addition of

In Japanese Patent Publication No. 61-26597, a water-based ink composition contains an N-alkanolamine such as triethanolamine or ethylethanolamine and urea, whereby drying resistance, cold resistance and freezing resistance are obtained. It has been proposed to improve properties, water resistance, heat resistance stability and the like. However, in the case of this ink, when the ink is ejected from a certain nozzle during printing by the inkjet recording method, and then the ink is not ejected from the nozzle for a certain period of time (for example, 1 minute), the nozzle is ejected. When the next first drop of ink is ejected (hereinafter referred to as intermittent ejection), stable ejection cannot be performed and printing is disturbed. Further, JP-A-60-124670 proposes to add an EO adduct of a triethanolamine derivative to an aqueous ink composition as an anti-clogging agent. However, even with this ink, if intermittent ejection is performed by the ink jet recording method, stable ejection cannot be performed and printing is disturbed. Further, there is a problem that a whisker-like bleeding occurs on the edge portion of the printed matter.

[0004]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an image of good character quality, which is excellent in ink clogging on a recording device and recovery of printing operation, does not cause bronzing on plain paper. And an ink having excellent storage stability, and an inkjet recording method using the same,
An object is to provide devices for inkjet recording.

[0005]

The above object can be achieved by the present invention described below. That is, the present invention includes an ink containing at least one compound represented by any one of the following general formulas (1) to (3), urea, a coloring material, and water, and an ink containing the same. The inkjet recording method and equipment used. (In the formula, R ¹ and R ² are a hydrogen atom, an alkyl group, a benzyl group, a —CH ₂ CH ₂ OH group, and a —CH ₂ CH (OH) CH.
₃ groups, R ³ and R ⁴ represent a hydrogen atom and a methyl group, and n
Represents an integer of 1 or more. ) (In the formula, R ¹ is a hydrogen atom, an alkyl group, a benzyl group,
CH ₂ CH ₂ OH group and -CH ₂ CH (OH) CH ₃ group,
R ² , R ³ , R ⁴ and R ⁵ represent a hydrogen atom and a methyl group, and n and m represent integers satisfying the relationship of m + n ≧ 1. ) (In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ represent a hydrogen atom and a methyl group, and n, m and p each represent an integer,
And these have a relation of m + n ≧ 1 and p ≧ 1)

The inventors of the present invention have conducted extensive studies to prevent bronzing on a printed material that occurs when an ink containing urea is used. As a result, the inventors have found that urea and the above general formulas (1) to (3) are contained in the ink. It was found that the bronzing phenomenon is dramatically improved by adding at least one kind of the compound represented by (4). Furthermore, when the ink of the present invention is applied to an ink jet recording apparatus, it was found that the problem of the clogging of the ink is good and that the beard-like bleeding does not occur at the edge portion of the obtained printed matter. Came to.

As described above, the ink of the present invention does not cause the defect bronze phenomenon due to the addition of urea, and on plain paper which is a defect of the compound represented by the general formulas (1) to (3). The reason why the edge of the printed matter does not cause whisker-like bleeding is not clear, but it is presumed as follows. Since urea is a solid, it is poorly fixed on paper and the dye aggregates on the printed matter, resulting in bronzing. On the other hand, the compounds represented by the general formulas (1) to (3) are
Since it has high penetrability into paper, a whisker-like bleeding will occur on the edge of the printed matter. However, urea and the above general formula (1) to
When the compound represented by (3) is combined and coexisted, the fixing to the paper is balanced, the bronzing phenomenon does not occur, and an image with good character quality without a whisker-like bleeding on the edge of the printed matter is obtained. You can

When the reason why the ink of the present invention has a very good problem of clogging when applied to an ink jet recording apparatus, the effect of preventing clogging of urea itself and the above general formula (1) ) To (3) are considered to be synergistic effects of the clogging prevention effect of the compounds. The effect is not only existing acid dyes, direct dyes and basic dyes, but also USP 5,053,495 specification,
EP 468649-A and EP 468647.
It was confirmed that even a low-solubility dye having a carboxyl group represented by the description of No. A can be used as a dye for an inkjet recording ink. Furthermore, it was confirmed that the printing stability was excellent when intermittent ejection was performed.

Further, more preferably, the general formula (1)-
Increasing the weight ratio of the compound represented by (3) to urea deteriorates the stability of intermittent discharge, and conversely, if the weight ratio of urea to the compound represented by the general formulas (1) to (3) is large, the bronze is increased. Therefore, it has been found that it is more effective to set the weight ratio of the compounds represented by the general formulas (1) to (3) and urea in the ink to 1: 1 to 1:15.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to preferred embodiments. The ink of the present invention is characterized by containing at least one compound represented by any one of the general formulas (1) to (3), urea, a coloring material and water. (In the formula, R ¹ and R ² are a hydrogen atom, an alkyl group, a benzyl group, a —CH ₂ CH ₂ OH group, and a —CH ₂ CH (OH) CH ₃
The groups R ³ and R ⁴ represent a hydrogen atom and a methyl group, and n represents an integer of 1 or more. ) (In the formula, R ¹ is a hydrogen atom, an alkyl group, a benzyl group,
CH ₂ CH ₂ OH group and -CH ₂ CH (OH) CH ₃ group, R
² , R ³ , R ⁴ and R ⁵ represent a hydrogen atom and a methyl group,
n and m represent integers that satisfy the relationship of m + n ≧ 1. ) (In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ represent a hydrogen atom and a methyl group, and n, m and p each represent an integer,
Moreover, these have a relationship of m + n ≧ 1 and p ≧ 1. )

The above general formulas (1) to (1) used in the present invention are as follows.
The number of additions of ethylene oxide and propylene oxide, which are the hydrophilic parts of the organic amine ethylene oxide and propylene oxide adducts represented by any one of (3), is the degree of familiarity of ethylene oxide and propylene oxide to the recording material. Considering the orientation, in the formula, the value of n is preferably an integer in the range of 1 to 7, and more preferably an integer in the range of 1 to 5. The value of m + n is preferably an integer in the range of 1-14, more preferably an integer in the range of 2-10. The value of p is preferably 7 or less, more preferably 5 or less. That is, when the values of n and m + n are smaller than 1, the ink clogging prevention property and the image bleeding are poor. When the value of m + n is greater than 14 and the value of p is greater than 7, the viscosity of the ink becomes too high, which is not preferable for use.

The weight ratio of the compounds represented by the general formulas (1) to (3) to urea is preferably 1: 1 to 1:15. The addition amount of the compounds represented by formulas (1) to (3) is preferably 0.05 to 20% by weight, more preferably 0.1 to 15% by weight. That is,
If the addition amount is less than 0.05% by weight, the ink clogging prevention property is poor. On the other hand, even if the amount is more than 20% by weight, no further effect can be expected, which is disadvantageous in terms of cost.

The amount of urea added to the ink of the present invention is preferably 0.5 to 20% by weight, more preferably 1 to 15% by weight. That is, if the amount of urea added is less than 0.5% by weight, there is no effect on the anti-clogging property, and if it is more than 20% by weight, urea crystals are likely to precipitate after long-term storage, which may rather cause clogging of the ink. It tends to occur. The weight ratio of the compounds represented by the general formulas (1) to (3) to urea is preferably 1: 1 to 1:15. That is, when the amount of the compounds represented by the general formulas (1) to (3) is larger than that of urea, the penetrability into paper is too high and bleeding easily occurs, and the general formulas (1) to (3) are generated. If the amount of the compound represented by is less than the amount of urea, it becomes difficult to prevent the bronzing phenomenon.

The coloring material used in the present invention includes:
Specific examples thereof include direct dyes, acid dyes, food dyes, basic dyes, reactive dyes, disperse dyes, soluble vat dyes, reactive disperse dyes, oil dyes, and various pigments such as carbon black. Among these, it is preferable to use a water-soluble dye from the viewpoint of ink performance. Furthermore, by using an aqueous dye having two or more carboxyl groups in the molecule, it becomes possible to obtain an image having excellent water resistance on plain paper. The addition amount of these coloring materials in the ink of the present invention is 0.1 to 15% by weight, and further 1 to 10%.
It is preferable to set the content to about% by weight.

Specific examples of the water-soluble dye used in the present invention include C.I. I. Food Black 2, C.I. I. Direct Black 168, C.I. I. Direct Black 154, C.I. I. Direct Yellow 86, C.I. I. Direct Yellow 142, C.I. I. Direct red 2
27, C.I. I. Direct Blue 199, C.I. I. Acid Blue 9 and the like can be given, but the present invention is not limited thereto.

Further, examples of the aqueous dye having a carboxyl group in the molecule which is preferably used in the present invention include dyes having the structures of the following general formulas (a) to (c). Of course, it is not limited to these dyes. (However, M represents a hydrogen atom, an alkali metal or ammonium)

[0017] (However, M represents a hydrogen atom, an alkali metal or ammonium)

[0018] (However, M represents a hydrogen atom, an alkali metal or ammonium)

In order to adjust the viscosity of the ink of the present invention to an appropriate viscosity suitable for use, it is preferable to use the water-soluble organic solvents used in conventionally known inks as described below. Specifically, for example, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-
Butyl alcohol, tert-butyl alcohol, isobutyl alcohol, n-pentanol and the like having 1 to 5 carbon atoms
Alkyl alcohols; amides such as dimethylformamide and dimethylacetamide; ketones or keto alcohols such as acetone and diacetone alcohol; ethers such as tetrohydrofuran and dioxane; diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene Oxyethylene or oxypropylene copolymers such as glycol, tripropylene glycol, polyethylene glycol, polypropylene glycol; ethylene glycol, propylene glycol, trimethylene glycol, triethylene glycol, 1,
Alkylene glycols having an alkylene group of 2 to 6 carbon atoms such as 2,6-hexanetriol and hexylene glycol; glycerin; ethylene glycol monomethyl (or ethyl) ether, diethylene glycol monomethyl (or ethyl) ether, triethylene glycol Lower alkyl ethers of polyhydric alcohols such as monomethyl (or ethyl) ether; lower dialkyl ethers of polyhydric alcohols such as triethylene glycol dimethyl (or ethyl) ether, tetraethylene glycol (or ethyl) ether; monoethanolamine, Alkanolamines such as diethanolamine and triethanolamine; sulfolane, N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone and the like. It is.

The content of the above water-soluble organic solvent contained in the ink of the present invention is generally in the range of 1 to 49% by weight, preferably 2 to 30% by weight based on the total weight of the ink. To do. The water-soluble organic solvent as described above can be used alone or as a mixture. The amount of water in the ink of the present invention is 50 to 98% by weight, preferably 60 to 90% by weight.

Further, in order to stabilize the solubility of the dye in the ink by keeping the pH value of the ink of the present invention constant,
The ink may contain a pH adjuster. Specific examples of the pH adjuster include hydroxides such as lithium hydroxide, sodium hydroxide, potassium hydroxide and ammonium hydroxide, sulfates such as lithium sulfate, sodium sulfate, potassium sulfate and ammonium sulfate, and lithium carbonate. ,
Sodium carbonate, sodium hydrogen carbonate, potassium carbonate,
Carbonates such as potassium hydrogen carbonate, sodium potassium carbonate, ammonium carbonate and ammonium hydrogen carbonate, lithium phosphate, monosodium phosphate, disodium phosphate,
Phosphates such as trisodium phosphate, monopotassium phosphate, dipotassium phosphate, tripotassium phosphate, monoammonium phosphate, diammonium phosphate, triammonium phosphate, lithium acetate, sodium acetate, potassium acetate and acetic acid Examples thereof include acetate salts such as ammonium.

These salts may be used alone by adding them to the ink, but it is more preferable to use two or more of these salts in combination. The total amount of these salts added is preferably 0.1 to 10% by weight, more preferably 1
８8% by weight. If the amount added is less than 0.1% by weight, it is difficult to keep the pH of the ink constant, and the effect on the dissolution stability of the aqueous dye contained in the ink is small. On the other hand, if the amount is more than 10% by weight, crystals of these salts are precipitated to cause nozzle clogging, which is not preferable. In the present invention, particularly when a dye having a low-solubility carboxyl group is used as a coloring material, the salt as described above is added to the ink to adjust the pH of the ink.
Is preferably adjusted in the range of 7 to 10.5.
If the pH is less than 7, the clogging property may be deteriorated, and if it is higher than 10.5, the ink contact member such as the recording head may be damaged, which is not preferable.

Further, the ink of the present invention contains, in addition to the above-mentioned ones, various conventionally known general additives such as a dispersant,
A surfactant, an antifungal agent and the like can be appropriately used in combination as necessary within a range not hindering the object of the present invention.

The recording material in which the ink of the present invention is used is, for example, ordinary plain paper such as high-quality paper, medium-quality paper, bond paper, coated paper, plastic film for OHP, and the like.
It can be used for any recording material.
Further, the ink of the present invention is preferably used in an inkjet recording system, particularly an inkjet recording system in which droplets are ejected by the action of heat energy for recording, but it goes without saying that it can also be used as a general writing instrument. Yes.

A recording method suitable for recording using the ink of the present invention is an ink jet recording method in which thermal energy corresponding to a recording signal is applied to the ink in the chamber of the recording head and a droplet is generated by the energy. However, a recording apparatus in which the ink of the present invention is preferably used will be described below with reference to the drawings.

An example of the structure of the head, which is the main part of the ink jet recording apparatus, is shown in FIGS. 1, 2 and 3. Head 1
Reference numeral 3 denotes a glass, ceramic or plastic plate having a groove 14 through which ink passes, and a heating head 15 used for thermal recording (thin film head is shown in the figure, but not limited to this). It is obtained by bonding. The heating head 15 has a protective film 1 formed of silicon oxide or the like.
6, 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 20 having a good heat dissipation property such as alumina.

The ink 21 is a discharge orifice (fine hole) 2
2, the meniscus 23 is formed by the pressure P. Now, when electrical signal information is applied to the aluminum electrodes 17-1 and 17-2, the area indicated by n of the heating head 15 rapidly heats up, and bubbles are generated in the ink 21 in contact with the area, and the pressure causes The meniscus 23 protrudes, the ink 21 is ejected and becomes an ink droplet 24, which is ejected from the ejection orifice 22 toward the recording material 25.

FIG. 3 shows an external view of a multi-head in which a large number of the heads shown in FIG. 1 are arranged. The multi-head is manufactured by closely adhering a glass plate 27 having a multi-groove 26 and a heating head 28 similar to that described in FIG. 1 is a cross-sectional view of the head 13 along the ink flow path,
FIG. 2 is a sectional view taken along the line AB of FIG.

FIG. 4 shows an example of an ink jet recording apparatus incorporating the above 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, which is in the form of a cantilever. The blade 61 is arranged at a position adjacent to the recording area of the recording head 65, and in the case of this example, is held in a form protruding in the movement path of the recording head 65. Reference numeral 62 denotes a cap of the ejection port surface of the recording head 65, which is disposed at a home position adjacent to the blade 61, moves in a direction perpendicular to the moving direction of the recording head 65, contacts the ink ejection port surface, and caps. Is provided. 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 movement path of the recording head 65.

The blade 61, the cap 62, and the ink absorber 63 constitute an ejection recovery section 64, and the blade 61 and the ink absorber 63 remove water, dust, and the like on the ink ejection port surface. Reference numeral 65 denotes a recording head which has an ejection energy generating means and ejects ink onto a recording material facing the ejection port surface where the ejection ports are arranged to perform recording.
Reference numeral 6 denotes a carriage on which the recording head 65 is mounted and which is moved.

The carriage 66 slidably engages with a 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 head 65 can move the recording area and its adjacent area.

Reference numeral 51 designates a paper feeding section for inserting a recording material, and 5
A paper feed roller 2 is 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 section provided with the ejection roller 53 as the recording progresses.

In the above structure, when the recording head 65 returns to the home position after the recording is completed, the cap 62 of the ejection recovery unit 64 is retracted from the movement path of the recording head 65, but the blade 61 projects into the movement path. There is. As a result, the ejection port surface 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 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 in the same position as the above-mentioned position during wiping. As a result, the ejection opening surface of the recording head 65 is wiped even during this movement. The movement of the print head 65 to the home position is performed not only at the end of printing or at the time of ejection recovery, but also at the home position adjacent to the printing area at a predetermined interval while the printing head 65 moves through the printing area for printing. And the wiping is performed with this movement.

FIG. 5 is a diagram showing an example of an ink cartridge in which the ink is supplied to the head through an ink supply member, for example, a tube. Here, 40 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. An ink absorber 44 receives the waste ink. It is preferable for the present invention that the ink containing portion has a liquid contact surface with 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 separately provided 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 containing portion containing ink, for example, an ink absorber is contained, and the ink in the ink absorber has a head portion having a plurality of orifices. The ink is ejected from 71 as an ink droplet.

It is preferable for the present invention to use polyurethane, cellulose or polyvinyl acetal 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.

[0038]

EXAMPLES Examples 1 to 8 and Comparative Examples 1 to 8 Next, the present invention will be described in more detail with reference to Examples and Comparative Examples of the present invention. First, inks of Examples 1 to 8 of the present invention were prepared using the components shown in Table 1 below. Also, the inks of Comparative Examples 1 to 8 were prepared using the components shown in Table 2. The pH of each ink was appropriately adjusted to about 9.5 using a 4N-lithium hydroxide aqueous solution. Table 1
And the structures of the dyes A to C in Table 2 are as shown in the following formulas, respectively.

[0039]

[0040]

[0041]

Table 1 Components of the inks of Examples 1-8

Table 2 Components of inks of Comparative Examples 1 to 8

[0044]

[Evaluation] Ink jet recording is performed by applying thermal energy to the ink in the recording head to generate droplets of the inks of the examples and comparative examples of the present invention, which include the ink components shown in Tables 1 and 2 above. The printer BJ-10ex (trade name: manufactured by Canon Inc.) was mounted and actually printed, and the following evaluation was performed. Table 3 shows the obtained evaluation results. The contents and conditions of each evaluation item are as follows.
As the recording material, 4024 paper manufactured by Xerox Co. was used.

Clogging property (fixing recovery property) A printer is filled with a predetermined ink and left for one month in an environment of 35 ° C., after which recovery operation (suction operation by pumping) is performed and then printing is performed. The following criteria were used for evaluation. ○: Return to normal printing state within 3 times of recovery operation △: Return to normal printing state within 4 to 5 times of recovery operation ×: Non-ejection or print disturbance occurs even after 6 or more recovery operations

Stability of intermittent ejection When a printer is filled with a predetermined ink and an alphanumeric character is continuously printed for 1 minute, printing is stopped, left for 1 minute without a cap, and then printed again. The following criteria were used to evaluate the fading and chipping of the characters. ◯: No blurring or chipping from the first character Δ: Part of the first character is faint or missing ×: The first character cannot be printed at all

Water resistance After the printer is filled with a predetermined ink to print a solid portion, the printing is stopped, and the printed matter is left for 1 hour or more.
The print density is measured by Macbeth RD915 (trade name: manufactured by Macbeth). Then, the printed matter was dipped in a container filled with water for 3 minutes, allowed to stand and dried, the print density was measured again, the residual rate of the print density was determined, and the water resistance was evaluated. ◯: Residual rate of printed matter density is 80% or more Δ: Residual rate of printed matter concentration is 66% or more and 79% or less ×: Residual rate of printed matter concentration is 65% or less

A bronze printer is filled with a predetermined ink, a solid portion is printed,
After leaving for 1 hour or more, the gloss of the solid part was visually evaluated according to the following criteria. ◯: There is no gloss and there is no unevenness in density, and Δ: There is some gloss, and there is unevenness and unevenness. X: There is gloss and unevenness on the entire surface.

Bleeding After printing alphanumeric characters with a printer and leaving it for 1 hour or more, the sharpness of the letters and the degree of the whisker-like bleeding generated from the letters were evaluated with a microscope and visually. ◯: Characters are sharp and do not have whisker-like bleeding. Δ: Characters are not sharp and slightly bleeding. ×: Characters are not sharp and have many bleeding.

Storage Stability Each ink was placed in a heat-resistant glass bottle in an amount of 100 cc, sealed and stored in a constant temperature bath at 60 ° C. for 2 months, then mounted in a printer for printing and evaluated according to the following criteria. ○: No abnormality. ×: No ejection, disordered printing, or discoloration.

Table 3 Evaluation results of Examples and Comparative Examples

[0052]

As described above, according to the present invention, an ink having excellent ink clogging on an ink jet recording apparatus and stability of printing during intermittent ejection, and further, when printing on plain paper, are used. Also, there is provided an ink which does not cause a bronzing phenomenon on a printed matter and can obtain an image with good character quality without a beard-like blurring on the edge portion of the printed matter. Furthermore, according to the present invention, a highly reliable ink that does not cause any problems even when used in an inkjet recording system is provided.

[Brief description of drawings]

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

FIG. 2 is a cross-sectional view of a head of an inkjet recording device.

FIG. 3 is an external perspective view of a head in which the head shown in FIG. 1 is multi-headed.

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

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

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

[Explanation of symbols]

 13: Head 14: Ink Groove 15: Heating Head 16: Protective Film 17: Aluminum Electrode 18: Heating Resistor Layer 19: Heat Storage Layer 20: Substrate 21: Ink 22: Discharge Orifice (Fine Hole) 23: Meniscus 24: Small Ink Droplet 25: Recording material 26: Multi-groove 27: Glass plate 28: Heating head 40: Ink bag 42: Plug 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: Ejection recovery part 65: Recording head 66: Carriage 67: Guide shaft 68: Motor 69: Belt 70: Recording unit 71: Head part 72: Atmosphere communication port

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Hisashi Teraoka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (16)

[Claims] 1. An ink containing at least one compound represented by any one of the following general formulas (1) to (3), urea, a coloring material and water. (In the formula, R ¹ and R ² are a hydrogen atom, an alkyl group, a benzyl group, a —CH ₂ CH ₂ OH group, and a —CH ₂ CH (OH) CH.
₃ groups, R ³ and R ⁴ represent a hydrogen atom and a methyl group, and n
Represents an integer of 1 or more. ) (In the formula, R ¹ is a hydrogen atom, an alkyl group, a benzyl group,
CH ₂ CH ₂ OH group and -CH ₂ CH (OH) CH ₃ group,
R ² , R ³ , R ⁴ and R ⁵ represent a hydrogen atom and a methyl group, and n and m represent integers satisfying the relationship of m + n ≧ 1. ) (In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ represent a hydrogen atom and a methyl group, and n, m and p each represent an integer,
Moreover, these have a relationship of m + n ≧ 1 and p ≧ 1. ) 2. The ink contains 0.05 to 20% by weight of compounds represented by the general formulas (1) to (3) and 0.5 to 0.5% of urea.
~ 20 wt%, coloring material 0.1-15 wt% and water 50
~ 98% by weight, and the general formula (1) ~
The weight ratio of the compound represented by (3) to urea is 1: 1 to
The ink according to claim 1, which is 1:15. 3. The ink according to claim 1, wherein the coloring material is a water-soluble dye. 4. The ink according to claim 3, wherein the water-soluble dye is a water-soluble dye having a carboxyl group as a dissociative group. 5. The ink according to claim 4, wherein the pH value of the ink is in the range of 7-10.5. 6. The ink according to claim 5, containing at least one inorganic salt selected from lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonium hydroxide, sulfates, carbonates and phosphates. . 7. An ink jet recording method for recording on a recording material by ejecting ink droplets from an orifice according to a recording signal, wherein the ink is the ink according to any one of claims 1 to 6. An inkjet recording method characterized by the above. 8. The ink jet recording method according to claim 7, wherein thermal energy is applied to the ink to eject ink droplets. 9. A recording unit comprising an ink containing section containing ink and a head section for ejecting the ink as ink droplets, wherein the ink is contained in any one of claims 1 to 6.
A recording unit comprising the ink according to any one of 1. 10. The head unit includes a head for causing thermal energy to act on ink to eject ink droplets.
Recording unit described in. 11. An ink cartridge provided with an ink containing portion containing ink, wherein the ink is the ink according to any one of claims 1 to 6. 12. An ink containing portion containing ink,
An ink jet recording apparatus comprising a recording unit having a head portion for ejecting the ink as an ink droplet, wherein the ink is the ink according to any one of claims 1 to 6. apparatus. 13. The head section includes a head for ejecting ink droplets by applying thermal energy to the ink.
2. The inkjet recording device according to 2. 14. An inkjet recording apparatus comprising a recording head for ejecting ink droplets, an ink cartridge having an ink accommodating portion for accommodating ink, and an ink supply portion for supplying ink from the ink cartridge to the recording head. An ink jet recording apparatus, wherein the ink is the ink according to any one of claims 1 to 6. 15. The ink jet recording apparatus according to claim 14, wherein the recording head is a head that applies thermal energy to ink to eject ink droplets. 16. The ink jet recording apparatus according to claim 14, wherein the ink containing portion has a liquid contact surface formed of polyolefin.