JPH06248212A - Ink, ink-jet recording method and recording apparatus using the ink - Google Patents

Abstract

PURPOSE:To obtain an ink containing a coloring agent and a liquid medium and having good storage stability and excellent properties to prevent bronzing defect and clogging trouble without deteriorating the water-resistance and quality of printed image by using an ammonium ion-containing dye, etc., as the coloring agent. CONSTITUTION:The ink contains (A) 0.1-10wt.% (based on the total weight of the ink) of a dye having at least one ammonium ion as the counter ion [preferably a dye having one or more carboxyl groups or a dye consisting of the compound of formula (R is NH4); Y is H or SO3R)], (B) 0.1-5wt.% of an inorganic acid or organic acid ammonium salt (preferably ammonium carbonate or ammonium phosphate) and (C) a liquid medium (preferably a mixture of 3-30wt.% of a water-soluble organic solvent and 30-95wt.% of water). The ink is preferably used for an ink-jet recording process utilizing thermal energy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink, an ink jet recording method using the ink, and an apparatus using the ink, and more specifically, copy paper, report paper, notebook, which are generally used in offices and homes. Ink suitable for non-coated paper such as letter paper, bond paper, continuous slip paper, so-called plain paper, which has excellent water resistance of the image and stability of dissolution of the ink, and which is suitable for a method of utilizing heat energy capable of high-quality recording, And an apparatus using the ink.

[0002]

2. Description of the Related Art Conventionally, ink jet inks having various compositions have been reported. Among them, copy paper, which is commonly used in offices in recent years,
Water resistance when recorded on plain paper such as report paper, notebooks, notepaper, bond paper, continuous slip paper, etc. is required,
On the other hand, detailed research and development have been conducted from various aspects such as ink composition and physical properties. For example, Japanese Patent Laid-Open No. 2-2
In Japanese Patent Application No. 96878 and Japanese Patent Application Laid-Open No. 2-255876, it is proposed that a water-based ink composition contains a polyamine.

However, in such an ink, since the hydrophilic base portion of the dye is salted with polyamine, the solubility of the ink is lowered, the reliability is lowered such as clogging at the nozzle tip, and the printed matter is not printed. In some cases, uneven printing may occur due to bronzing (association of dyes), or the density may not appear.
It is also possible to include a dissolution stabilizer in the ink for the purpose of increasing the solubility of the ink. In this case, however, since a large amount of the dissolution stabilizer must be added, the ink was formed using such an ink. The image quality of recorded matter deteriorates.

Further, in JP-A-3-91577, the dye has a carboxyl group, and when an ammonium salt or a volatile substituted ammonium salt is used, ammonia or amine is volatilized on the recorded matter, It has been proposed to improve the water resistance by becoming a free acid. However, even in this case, even though the initial solubility of the ink is good, the solubility of the dye is lowered due to the gradual volatilization of ammonia or amine in the ink, resulting in nozzle clogging and ink stability. It often causes a decrease in sex. For the same reason, bronzing is also likely to occur on a recorded matter, especially on acid paper.

[0005]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to use non-coated paper such as copy paper, report paper, notebook, notepaper, bond paper, and continuous slip paper, which are generally used in offices and homes, so-called. An ink that can prevent bronzing on a recorded matter without adversely affecting the water resistance and image quality of an image when recorded on plain paper, and that has solved the problems of ink clogging and storage stability. An object of the present invention is to provide an inkjet recording method using the same and a device using the ink.

[0006]

The above object can be achieved by the present invention described below. That is, the present invention is characterized in that an ink containing a colorant and a liquid medium in which the colorant is dissolved contains a dye having at least one ammonium ion as a counter ion and an ammonium salt of an inorganic acid or an organic acid. An ink, an inkjet recording method using the ink, and a device using the ink.

[0007]

The present inventors have conducted extensive studies on various ink compositions for the purpose of dissolving stability of the ink having excellent water resistance and preventing bronzing on the recorded matter. As a result, the coloring agent and the coloring agent are dissolved. In an ink containing a liquid medium, an ink containing a dye having at least one ammonium ion as a counter ion, and an ammonium salt of an inorganic acid or an organic acid, without impairing the water resistance of the dye,
The inventors of the present invention have found that the ink has excellent dissolution stability, that is, it does not cause clogging at the tip of the nozzle, and that it has good bronzing prevention properties on the recorded matter.

The reason for this is that since the ammonium salt of an inorganic acid or an organic acid dissociates and excess ammonium ions exist in the ink, even if ammonia is volatilized at the nozzle tip or during long-term storage, the dye becomes a free acid. It is considered that this is because the precipitation of the dye does not occur.
Also, in printing, when the inorganic acid or organic acid ammonium salt is not contained, the dye immediately precipitates in the form of a free acid and causes bronzing on the recorded matter, whereas the inorganic acid or organic acid ammonium salt is formed. When a salt is contained, the speed at which the dye deposits is relatively slow, and it is considered that the ink appropriately permeates into the recorded matter and does not cause bronzing. Among them, the ink containing ammonium carbonate or ammonium phosphate is particularly effective in achieving the object of the present invention because the pH does not decrease due to the volatilization of ammonia.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the preferred embodiments. Specific examples of the ammonium salt of an inorganic acid or an organic acid used in the present invention include ammonium carbonate, ammonium phosphate (triammonium phosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate), ammonium borate, Examples of such compounds include ammonium acetate and ammonium sulfate, and among these compounds, ammonium carbonate and ammonium phosphate are particularly preferable, but the present invention is not limited thereto. The amount of the above compound added to the ink varies depending on the colorant used, other liquid medium used in combination, etc., but is preferably in the range of 0.01 to 10% by weight, and more preferably 0.
It is in the range of 1 to 5% by weight.

As the dye having at least one ammonium ion as the counter ion used in the present invention, various known dyes are used, but preferably, the dye having at least one carboxyl group or the following structural formula ( It is a compound represented by a). Specific examples are shown below, but the present invention is not limited thereto.

[0011]

[Chemical 2]

[0012]

[Chemical 3]

[0013]

[Chemical 4]

[0014]

[Chemical 5]

[0015]

[Chemical 6] The amount of the above dye added to the ink is in the range of 0.1 to 15% by weight, preferably 0.1 to 10% by weight. In addition to the above components, the ink of the present invention contains a water-soluble organic solvent, a surfactant, a pH adjuster, a rust preventive, an antiseptic, a fungicide, an antioxidant, an evaporation accelerator, and a chelating agent, if necessary. Various additives such as agents and water-soluble polymers may be added.

The liquid medium used in the present invention is preferably a mixture of water and a water-soluble organic solvent. Specific examples of the water-soluble organic solvent include, for example, amides such as dimethylformamide and dimethylacetamide; ketones such as acetone; 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,
Alkylene glycols in which the alkylene group such as diethylene glycol contains 2 to 6 carbon atoms; glycerin; ethylene glycol monomethyl (or ethyl) ether,
Diethylene glycol monomethyl (or ethyl) ether, Triethylene glycol monomethyl (or ethyl)
Lower alkyl ethers of polyhydric alcohols such as ethers; N-methyl-2-pyrrolidone, 1,3-dimethyl-
2-imidazolidinone, triethanolamine, sulfolane, dimethyl sulfoxide, 2-pyrrolidone,
Examples include cyclic amide compounds such as ε-caprolactam and imide compounds such as succinimide.

The content of the water-soluble organic solvent is generally preferably 1% to 40% by weight, more preferably 3% to 30%, based on the total weight of the ink. Further, the content of water in the ink is used in the range of 30 to 95% by weight. If it is less than 30% by weight, the solubility of the colorant is deteriorated and the viscosity of the ink is increased, which is not preferable. on the other hand,
If it is more than 95% by weight, the amount of vaporized components is too large to satisfy a sufficient fixing property.

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

Further, the ink of the present invention solves the problem of the water resistance of the printed matter when recorded on plain paper or the like, and at the same time improves the matching with the ink jet head, the physical properties of the ink itself. As 25 ℃
Surface tension at 30-68 dyne / cm, viscosity 1
It is desirable to adjust it to 5 cP or less, preferably 10 cP or less, and more preferably 5 cP or less. Therefore, in order to adjust the ink to the above physical properties and solve the problem of plain paper, the amount of water contained in the ink of the present invention is 50% by weight or more and 98% by weight or less, preferably 60% by weight.
It is preferably not less than 95% by weight.

The ink of the present invention is particularly suitable for use in an ink jet recording method in which droplets are ejected by the action of heat energy for recording, but it can also be used for general writing instruments. As a method and apparatus suitable for performing recording using the ink of the present invention, a method and apparatus for applying thermal energy corresponding to a recording signal to the ink in the chamber of the recording head and generating droplets by the thermal energy are provided. Can be mentioned.

An example of the head structure, which is the main part of the apparatus, is shown in FIGS. 1, 2 and 3. The head 13 is a glass, ceramic or plastic plate having a groove 14 through which ink passes, and a heating head 15 used for thermal recording.
(The head is shown in the figure, but the present invention is not limited to this.). Fever head 15
Is 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 base plate 20 having good heat dissipation such as alumina. Has become

The ink 21 has a discharge orifice (fine hole) 2
2, the meniscus 23 is formed by the pressure P. Now, when electric signal information is applied to the electrodes 17-1 and 17-2, the area indicated by n of the heating head 15 rapidly generates heat, and bubbles are generated in the ink 21 in contact therewith, and the meniscus is generated by the pressure. 23 protrudes, the ink 21 is ejected, becomes a recording droplet 24 from the orifice 22, and flies toward the recording material 25.

FIG. 3 shows an external view of a multi-head in which many heads shown in FIG. 1 are arranged. The multi-head is manufactured by closely contacting a glass plate 27 having a multi-groove 26 and a heating head 28 similar to that described 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 such a head. In FIG. 4, reference numeral 61 denotes a blade as a wiping member, one end of which is held by a blade holding member 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, and in the case of this example, is held in a protruding form in the movement path of the recording head.

Reference numeral 62 denotes a cap, which is arranged at a home position adjacent to the blade 61, and has a structure in which it moves in a direction perpendicular to the moving direction of the recording head and comes into contact with the ejection port surface to perform capping. Further, 63 is a blade 61
Is an absorber that is provided adjacent to, and is held in a protruding form in the movement path of the recording head, like the blade 61. The blade 61, the cap 62, and the absorber 63 form an ejection recovery unit 64, and the blade 61 and the absorber 63 remove water, dust, and the like on the ink ejection port surface.

Reference numeral 65 denotes a recording head having ejection energy generating means for ejecting ink to a recording material facing the ejection port surface having the ejection ports for recording, and 66 a recording head having the recording head 65 mounted thereon. A carriage for moving 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 head 65 can move the recording area and its adjacent area. Reference numeral 51 is a paper feed section for inserting a recording material, and 52 is a paper feed roller driven by a motor (not shown). With these configurations, the recording material is fed to a position facing the ejection port surface of the recording head, and is ejected to a paper ejection unit provided with a paper ejection roller 53 as the recording progresses.

In the above structure, when the recording head 65 returns to the home position after recording is completed, the cap 62 of the head recovery section 64 is retracted from the movement path of the recording head 65, but the blade 61 is projected 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. Recording head 6
When 5 moves from the home position to the recording start position, the cap 62 and the blade 61 are at the same position as the above-described position at the time of wiping. As a result, the ejection opening surface of the recording head 65 is wiped even during this movement.

The above-described movement of the recording head to the home position is performed not only at the end of recording or at the time of ejection recovery but also at the home adjacent to the recording area at a predetermined interval while the recording head moves in the recording area for recording. The wiper is moved to the position, and the wiping is performed along with the move. FIG. 5 is a diagram showing an example of an ink cartridge in which the ink is supplied to the head via 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. Needle (not shown) in this stopper 42
The ink in the ink bag 40 can be supplied to the head by inserting. Reference numeral 44 is an absorber that receives waste ink.

As the ink containing portion, it is preferable for the present invention that the liquid contact surface with the ink is formed of polyolefin, especially polyethylene. The ink jet recording apparatus used in the present invention is not limited to the above-described head and ink cartridge which are separate bodies, but may be preferably used as an integrated one as shown in FIG.

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 plurality of orifices. Head portion 71
It is configured to be ejected as an ink droplet from.

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.

EXAMPLES Next, the present invention will be described more specifically with reference to Examples and Comparative Examples. In the text, "part" and "%" are based on weight unless otherwise specified.

Examples 1 to 5 The following components were mixed, thoroughly stirred and dissolved, and then pressure-filtered with a Fluoropore filter (trade name: Sumitomo Electric Industries, Ltd.) having a pore size of 0.45 μm to obtain the present invention. The inks of Example 1 were prepared respectively. Ink composition of Example 1 Compound (Y = H) represented by structural formula (a) 2 parts Triammonium phosphate 0.5 part Glycerin 15 parts Isopropyl alcohol 3 parts Water 79.5 parts

Ink composition of Example 2 Compound (Y = H) represented by formula (a) 2.5 parts Ammonium carbonate 1 part 2-Pyrrolidone 10 parts Water 86.5 parts Ink composition structural formula of Example 3 ( Compound represented by a) (Y = SO ₃ R) 2.5 parts Ammonium acetate 2 parts Diethylene glycol 15 parts Water 80.5 parts

Ink composition compound (1) of Example 4 2 parts Triammonium phosphate 1 part 2-Pyrrolidone 15 parts Ethanol 5 parts Water 77 parts

Ink composition compound (1) of Example 5 2.5 parts Ammonium carbonate 0.5 part Thiodiglycol 10 parts Urea 5 parts Isopropyl alcohol 4 parts Water 78 parts

Comparative Examples 1 to 5 In the compositions of Examples 1 to 5, inks of Comparative Examples 1 to 5 were prepared by removing the ammonium salt of an inorganic acid or an organic acid from each composition and supplementing the deficiency with pure water. did. Next, a printing test was performed using the inks of Examples 1 to 5 and Comparative Examples 1 to 5 obtained above and an on-demand type ink jet printer using a heating element as an ink discharge energy source as an ink jet recording apparatus. Do (1)
The clogging property, (2) bronze on the recorded matter, (3) print quality, and (4) water resistance were evaluated according to the following criteria. The evaluations obtained are shown in Table 1.

(Evaluation Method and Evaluation Criteria) (1) Evaluation of Clogging Property (Fixing Recovery Property) The printer was left in a constant temperature bath at 35 ° C. for 1 month, and then left at room temperature for 24 hours to perform a recovery operation (by pumping). After performing the suction operation), printing was performed, and evaluation was performed according to the following criteria. ◯: The printing state returns to normal within five recovery operations. Δ: The printing state returns to normal after 6 to 10 times of recovery operation. X: No ejection or disorder of printing occurs after 6 to 10 times of recovery operation.

(2) Evaluation of Bronze on Recorded Material A solid part was printed on a commercially available copy paper with a printer, left for 1 hour or more, and visually evaluated for gloss of the solid part. ◯: There is no gloss and the density is uniform and uniform. Δ: Partially glossy, uneven and uneven. X: The entire surface is glossy and uneven.

(3) Evaluation of printing quality After printing alphanumeric characters on a commercially available copy paper with a printer and leaving it for 1 hour or more, the sharpness of the characters and the degree of the whisker-like bleeding caused by the characters are visually observed with a microscope. evaluated. ○: Characters are sharp and there is no beard-like blurring. Δ: Characters are not sharp and slightly blurred. Δ: Characters are not sharp and have many blurs.

(4) Evaluation of Water Resistance A printer was used to print alphanumeric characters and solid portions on commercially available copy paper, and after leaving it for 1 hour or more, the print density was changed to Macbeth R.
D915 (trade name: manufactured by Macbeth) is used for measurement. After that, after immersing the printed matter in a container filled with water for 3 minutes,
After leaving and drying, the print density was measured again, the residual ratio of the print density was determined, and the water resistance was evaluated. ◯: The residual rate of printed matter density is 80% or more. Δ: The residual rate of printed matter density is 66% or more and 79% or less. X: The residual density of printed matter is 65% or less.

[0040]

[Table 1]

[0041]

As described above, according to the present invention, water resistance and image quality of an image when recorded on so-called plain paper such as copy paper generally used in offices and homes may be adversely affected. It is possible to effectively prevent bronze on the recorded matter. Furthermore, according to the present invention, it is possible to obtain an ink having good anti-clogging property and storage stability.

[0042]

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a recording head according to an inkjet recording method of the present invention.

FIG. 2 is a schematic cross-sectional view showing a sectional view taken along the line AB of FIG.

FIG. 3 is a schematic external view showing an example of a multi-head in which a large number of heads in FIG. 1 are arranged.

FIG. 4 is a schematic perspective view showing an example of an ink jet recording apparatus incorporating the same head.

FIG. 5 is a schematic cross-sectional view showing an example of an ink cartridge that supplies ink to the head.

FIG. 6 is a schematic external view showing an example of a main part of an inkjet recording apparatus in which the same head and the same ink cartridge are integrated.

[Explanation of sign]

 13: Head 14: Ink Groove 15: Heating Head 16: Protective Layer 17: Aluminum Electrode 18: Heating Resistor Layer 19: Heating Layer 20: Substrate 21: Ink 22: Discharge Orifice 23: Meniscus 24: Ink Droplet 25: Cover Recording material 26: Multi-groove 27: Glass plate 28: Heating head 40: Ink bag 42: Pillar 44: Ink absorber 45: Ink cartridge 51: Paper feed section 52: Paper feed roller 52: Paper discharge roller 61: Blade 62: Cap 63: Ink absorber 64: Ejection recovery section 65: Recording head 66: Carriage 67: Guide shaft 68: Motor section 69: Belt 70: Inkjet cartridge

Front page continuation (72) Inventor Takao Yamamoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Takeshi Eita 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (17)

[Claims] 1. An ink containing a colorant and a liquid medium in which the colorant is dissolved, wherein the ink contains a dye having at least one ammonium ion as a counter ion, and an ammonium salt of an inorganic acid or an organic acid. . 2. The ink according to claim 1, wherein the dye having at least one ammonium ion as a counter ion has at least one carboxyl group. 3. The ink according to claim 1, wherein the dye having at least one ammonium ion as a counter ion is a compound represented by the following structural formula (a). [Chemical 1] 4. The ink according to claim 1, 2 or 3, wherein the ammonium salt of an inorganic acid is ammonium carbonate or ammonium phosphate. 5. 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 contains a dye having at least one ammonium ion as a counter ion, an inorganic acid or An ink jet recording method comprising an ink containing an ammonium salt of an organic acid. 6. The ink jet recording method according to claim 5, wherein thermal energy is applied to the ink to eject ink droplets. 7. A recording unit comprising an ink containing portion containing ink and a head portion for ejecting the ink as ink droplets, wherein the ink contains a dye having at least one ammonium ion as a counter ion, and an inorganic material. A recording unit, which is an ink containing an acid or an ammonium salt of an organic acid. 8. The recording unit according to claim 7, wherein the head portion is a head that causes thermal energy to act on the ink to eject ink droplets. 9. The recording unit according to claim 7, wherein the ink containing portion is formed of polyurethane, cellulose, or polyvinyl acetate. 10. An ink cartridge provided with an ink containing portion containing ink, wherein the ink contains a dye having at least one ammonium ion as a counter ion, and an ammonium salt of an inorganic acid or an organic acid. An ink cartridge characterized in that there is. 11. The ink cartridge according to claim 10, wherein the ink containing portion has a liquid contact surface formed of polyolefin. 12. An inkjet recording apparatus comprising a recording unit having an ink containing section containing ink and a head section for ejecting the ink as ink droplets, wherein the ink is at least one ammonium ion as a counter ion. An ink jet recording apparatus, which is an ink containing a dye having a salt and an ammonium salt of an inorganic acid or an organic acid. 13. The head unit is a head for causing thermal energy to act on ink to eject ink droplets.
2. The inkjet recording device according to 2. 14. The ink jet recording apparatus according to claim 12, wherein the ink containing portion is formed of polyurethane, cellulose, or polyvinyl acetate. 15. A recording head for ejecting ink droplets,
In an ink jet recording apparatus having an ink cartridge having an ink containing portion containing ink and an ink supplying portion for supplying ink from the ink cartridge to a recording head, the ink has at least one ammonium ion as a counter ion. An ink jet recording apparatus, which is an ink containing a dye and an ammonium salt of an inorganic acid or an organic acid. 16. The ink jet recording apparatus according to claim 15, wherein the recording head is a head that applies thermal energy to ink to eject ink droplets. 17. The ink jet recording apparatus according to claim 15, wherein the ink containing portion has a liquid contact surface formed of polyolefin.