JP2003182111A - Ink and ink tank - Google Patents

Abstract

(57) [Problem] To provide an ink with high reliability and high reliability, and an ink tank which contains such an ink with good performance, has excellent visibility, and has few unnecessary components. SOLUTION: An ink tank containing ink transmits visible light and ultraviolet light, and an ultraviolet cut film for reducing ultraviolet light is adhered to the tank. The film is a film or a coating film, and preferably reduces ultraviolet rays by 80% or more. The ink is characterized in that it contains an acrylate or methacrylate having at least a primary skin irritation rate of 6 or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet ink which is particularly safe and reliable, and an ink tank which contains such ink with good performance, and more specifically, a composition which is excellent in visibility and is unnecessary. There are few ink tanks.

[0002]

2. Description of the Related Art Recently, an ink having a property of being cured by being irradiated with ultraviolet rays (ultraviolet curing ink) has been used as an ink composition for ink jet. Since the printer has a built-in UV light source that quickly cures the UV curable ink ejected onto the paper surface during printing, the inside of the printer is exposed to UV light during printing, and the ink tanks inside the printer are also exposed. It will be irradiated with ultraviolet rays.

Further, even in the case of water-based ink, deterioration of the dye and discoloration of the dye are caused particularly when the ink containing the dye as the coloring material is contained.

An ink tank containing such an ink is disclosed in Japanese Patent Laid-Open No. 2001-63099.

[0005]

SUMMARY OF THE INVENTION In the above publication,
The ink tank is made of a resin capable of reducing the ultraviolet light from the outside of the housing to the inside of the ink containing portion, but the case where the housing is not used is not disclosed. Therefore, the ink and the ink tank, which have many unnecessary components and are high in price, are extremely disadvantageous to the user. Further, the above publication does not mention that an ink tank for containing ink is used for containing waste ink.

On the other hand, there are cases where the ink tank is made brown or black due to the importance of the light-shielding property. This tendency is often seen when accommodating ink using dye as a coloring material or UV curable ink, but the remaining amount and color of the ink cannot be recognized at a glance, which hinders understanding of the replacement time. It was

Ideally, the ink is not wasted, but is recovered and reused. However, particularly when the ultraviolet curable ink is discarded, the odor is a problem because it is uncured while being absorbed by the absorber or the like and is exposed to the atmosphere.

In view of the above, an object of the present invention is to provide an ink which is highly safe and highly reliable, and an ink tank which contains such an ink with good performance and has excellent visibility and less unnecessary components. Especially.

[0009]

In order to solve the above-mentioned problems, in the present invention, an ink tank containing ink transmits visible light and ultraviolet rays, and a film for attenuating ultraviolet rays is adhered to the tank. . Ink tank 400 to 7
The film having a mean light transmittance of visible light at 00 nm of 0.1% or more and attenuating ultraviolet rays may be a film or a coating film. Further, it is preferable that this film attenuates ultraviolet rays by 80% or more.

Further, it is preferable that the ink contained in the ink tank is for an ink jet printer which discharges from a nozzle for recording and contains at least an acrylate or a methacrylate having a primary skin irritation rate of 6 or less.

More preferably, it is preferable to remove the ultraviolet ray-attenuating film from the ink tank, store the waste ink, and irradiate the ultraviolet ray.

[0012]

FIG. 1 shows an ink tank of the present invention. Reference numeral 1 is an ink tank, 2 is ink, and 3 is an ultraviolet ray blocking film which is brought into close contact with the surface of the ink tank 1 to reduce ultraviolet rays. The ink tank 1 used in the present invention is not particularly limited as long as it has resistance to the ink 2, and a commercially available tank can be used as it is. It is preferable that the ink tank 1 has excellent visibility so that the remaining amount of the ink 2 can be confirmed and the color can be grasped. For example, low density polyethylene, high density polyethylene, polypropylene, polymethylpentene, ethylene propylene fluoride, perfluoroalkoxy, polysulfone, polyethylene terephthalate copolymer, fluorine processed high density polyethylene, fluorine processed low density polyethylene, polyacetal, polyethylene terephthalate, etc. Some are molded in. Excellent visibility means that the ink in the container can be seen from the outside.
It is preferable that the tank is a transparent or semi-transparent tank that transmits visible light of nm. Specifically, if the average transmittance of 400 to 700 nm is less than 0.1%, it is difficult to confirm the remaining amount of ink.
0.1% or more is preferable, and 10% or more is particularly preferable.
However, an opaque portion may be provided by providing a white pigment layer in a part of the tank as an information display portion for printing or writing. The thickness is such that the shape can be maintained without protection of the housing,
200 μm or more is desirable. Further, since the ultraviolet ray cutting film for reducing the ultraviolet rays is brought into close contact with the ink tank 1, the tank 1 itself does not need to be the one for reducing the ultraviolet rays. The capacity of the tank 1 is not particularly limited because it depends on the recording form, but it is preferably about 200 to 1000 ml. The ink tank 1 containing the inkjet ink may be integrated with the recording head or may be separate, but it is convenient to separate the ink tank 1 because the material and shape of the ink tank 1 are not limited. is there.

The ultraviolet ray blocking film 3 adhered to the ink tank 1 may be attached to the ink tank 1 or coated, or a combination of both, unless the visibility of the ink tank 1 is significantly deteriorated. May be. Here, the film is defined to include not only a continuous film-shaped film but also a discontinuous layer. As the sticking type film, there is a sheet-shaped or tape-shaped film, which can be used after being laminated.
The material of the film is not limited, but examples thereof include polyolefin and polyvinyl chloride. As means for reducing ultraviolet rays, titanium oxide or an ultraviolet absorber is added, and a photocatalyst layer is provided. Specifically, the ultraviolet absorber is salicylic acid-based,
Benzophenone-based, benzotriazole-based, cyanoacrylate-based, etc. are appropriately selected. Commercially available ultraviolet cut films, pouch films, ultraviolet cut laminates, overcoat layers and the like can be used. It is also effective to attach it as a protective layer of a paper label. As coating type film, powder, wax or emulsion type coating device, brush or rubber blade, sponge,
It is formed by makeup puff, spray, dipping, etc. Or
Commercially available cosmetic creams and powders may be used.

80% as a UV reduction rate
Or more, more preferably 90% or more. Light rays called ultraviolet rays are a general term for light in a region having a shorter wavelength than visible light and longer than X-rays. Generally, those having a wavelength of 100 to 400 nm are called ultraviolet rays, but in the present invention, the extinction rate of ultraviolet rays was calculated by the ultraviolet ray transmittance at 360 nm. That is, when the ultraviolet transmittance is 20%, the extinction ratio is 80%. The thickness of the film is thinner than that of the ink tank and is preferably less than 200 μm, particularly preferably 30 to 100 μm.

The ink 2 contained in the ink tank 1 of the present invention is not particularly limited. Specifically, there are water-based inks containing water or a water-soluble organic solvent as a main component, non-aqueous inks containing an aliphatic solvent as a main component, and ultraviolet curable inks that insolubilize the ink in a recording medium by light. INDUSTRIAL APPLICABILITY The ink tank of the present invention can more effectively prevent color deterioration and change in performance, particularly in the case of an ink in which a dye or a fluorescent agent sensitive to light is added to a color material. In addition, when the curing reaction proceeds due to ultraviolet rays as in the case of ultraviolet curable ink, it is possible to prevent this and to maintain a state where stable ejection is possible. In addition, in the present invention, all of the colorants such as dyes and pigments, inorganic pigments, powder metals and the like that can be dispersed in the main component are treated as the ink 2.

The ink 2 is ideally collected and reused without being wasted, but it is difficult to collect all the ink. When the UV curable ink is cured, the acrylic monomer is consumed and skin irritation is drastically reduced. Therefore, for safety and operability, it is desirable that the discarded ink be cured. An ultraviolet light source for quickly curing the ultraviolet curable ink ejected on the paper surface during printing,
At the same time, it is efficient to cure the ink by irradiating the waste ink.

In the brown and black ink tanks that prevent the transmission of ultraviolet rays, curing does not easily occur even if waste ink is stored,
The ink tank 1 of the present invention can be used as a waste ink tank because it transmits ultraviolet rays and accelerates curing. In order to secure further safety, it is important to set the primary skin irritation index (hereinafter referred to as PI) of the ink within an appropriate range. P. I. I is measured by the Draize method, and the measured values are distributed in 0 to 8, and the smaller the value, the lower the irritation. According to Kiyomi Kato, "Ultraviolet Curing System": According to the Center for Advanced Technology, skin irritation of acrylic monomers varies depending on the molecular weight, molecular structure, and viscosity. I. I is large. In addition, the viscosity and P.
I. Regarding I, the behavior basically shown by the following formula is known.

P. I. I = 5489-1182 log η Here, η is the viscosity at 25 ° C. That is, the higher the viscosity, the higher the P. I. I becomes smaller. There is a trade-off between low viscosity and skin irritation. Since the viscosity of a general ultraviolet curable ink for screen printing is tens of thousands mPa · s, which is about 100 to 1000 times the viscosity of the ink for inkjet, P. I. It is easy to lower I. Further, the curing proceeds faster with the polyfunctional acrylic monomer than with the monofunctional acrylic monomer. Compared to monofunctional monomers, polyfunctional monomers have less skin irritation and are easier to handle. However, the ink composition for inkjet printers has a high viscosity and does not play the original role of the monomer added as a reactive diluent. That is, an ink for inkjet is expected to have a material having a low viscosity, a low skin irritation and a high reactivity, which are contrary to each other.

Ink 2 effective in the present invention is P.I. I. I is low. P. I. As a means to lower I,
It is conceivable that the molecular weight is increased, acrylate is methacrylated, ethylene oxide or polyethylene oxide is modified, but is particularly effective. Specifically, the safety measures for Ink 1 are performed on the equipment.
I. I = 7 or less is preferable. More preferably, 5 or less,
More preferably, it can be supplied, collected and discarded more safely when it is 2 or less. Alkyl (meth) as acrylate
Acrylate, alicyclic (meth) acrylate, alkylene glycol type (meth) acrylate, ester type (meth) acrylate, trimethylolpropane type (meth)
Acrylate, pentaerythritol type (meth) acrylate, isocyanurate type (meth) acrylate, phenyl type (meth) acrylate, benzyl type (meth) acrylate, phenoxy type (meth) acrylate, bisphenol A type (meth) acrylate, alcohol type ( (Meth) acrylate, epoxy type (meth) acrylate, allyl type (meth) acrylate, glycidyl type (meth) acrylate, carboxyl type (meth) acrylate, vinyl type (meth) acrylate, ether type (meth) acrylate and the like. it can. For example, monofunctional 2-ethylhexyl (meth) acrylate (E
HA), 2-hydroxyethyl (meth) acrylate (HEA), 2-hydroxypropyl (meth) acrylate (HPA), caprolactone-modified tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylate, 3-methoxybutyl (meth). Acrylate,
Tetrahydrofurfuryl (meth) acrylate, lauryl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, isodecyl (meth) acrylate,
Isooctyl (meth) acrylate, tridecyl (meth) acrylate, caprolactone (meth) acrylate, ethoxylated nonylphenol (meth) acrylate, bifunctional tripropylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene Glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol hydroxypivalic acid ester di (meth) acrylate (MANDA) and hydroxypivalic acid neopentyl glycol ester di (meth) acrylate (HPNDA), 1,3- Butanediol di (meth) acrylate (BGDA), 1, 4
-Butanediol di (meth) acrylate (BUD
A) 1,6-hexanediol di (meth) acrylate (HDDA), 1,9-nonanediol di (meth) acrylate, diethylene glycol di (meth) acrylate (DEGDA), neopentyl glycol di (meth) acrylate (NPGDA) ), Tripropylene glycol di (meth) acrylate (TPGDA), caprolactone modified hydroxypivalic acid neopentyl glycol ester di (meth) acrylate, propoxylated pentyl glycol di (meth) acrylate, ethoxy modified bisphenol A di (meth) acrylate, Polyethylene glycol 200 di (meth) acrylate, polyethylene glycol 400 di (meth) acrylate, polyfunctional trimethylolpropane tri (meth) acrylate (TMPTA) Pentaerythritol tri (meth) acrylate (PETA), dipentaerythritol hexa (meth) acrylate (DPHA), triallyl isocyanate, ε-caprolactone-modified dipentaerythritol (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (Meth) acrylate, ethoxylated trimethylolpropane tri (meth) acrylate, propoxylated trimethylolpropane tri (meth) acrylate, propoxylated glyceryl tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) ) Acrylate, dipentaerythritol hydroxypenta (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate , Penta (meth) acrylate ester, N, N-dimethylacrylamide, N-methylolacrylamide, N-vinylformamide, N-acryloylmorpholine, isobonyl (meth) acrylate, dicyclopentenyl (meth) acrylate, cyclohexyl (meth) acrylate , Polyester (meth) acrylate, bisphenol epoxy (meth) acrylate, bisphenol A
-Based epoxy (meth) acrylate, propylene oxide-modified bisphenol A-based epoxy (meth) acrylate, alkali-soluble epoxy (meth) acrylate, acrylic modified epoxy (meth) acrylate, phosphoric acid modified epoxy (meth) acrylate, polycarbonate-based urethane (meth) ) Acrylate, polyester-based urethane (meth) acrylate, alicyclic urethane (meth) acrylate, aliphatic urethane (meth) acrylate, polybutadiene (meth) acrylate, polystyryl (meth)
An acrylate etc. can be mentioned. One or more of these (meth) acrylates can be used.

In view of the above, an object of the present invention is to provide an ink which is highly safe and reliable, and an ink tank which contains such ink with good performance, has excellent visibility, and has a small number of unnecessary components. .

Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to the examples. [Examples 1 and 2 and Comparative Examples 1 and 2] The translucent polypropylene ink tanks (average transmittance of visible light of 400 to 700 nm: 10%) were dimmed with ultraviolet rays (dimming ratio of 90%).
A film (UV cut 100A, manufactured by Toshin Sangyo Co., Ltd., Example 1) is applied, and a transparent polymethylpentene ink tank (average transmittance 90% at 400 to 700 nm) is dimmed with ultraviolet light (dimming ratio). (95%) (aqua veil, product of TMP, Example 2) was attached, and 30 g of an aqueous dye ink was injected. The ink is 42 parts by weight of purified water, 50 parts by weight of glycerin, 5 parts by weight of dipropylene glycol monomethyl ether, black dye dispersion (Norient Chemical, N
UBIAN BLACK PC-0850) 3 parts by weight of a total of 300 g are dispersed using a homogenizer (HG30 manufactured by Hitachi Koki) at a rotation speed of 2,000 rpm until a homogeneous mixture is obtained, and then filtered to remove impurities and the like. Then
A homogeneous aqueous dye ink was obtained. For comparison, the film is not adhered to the ink tank of Example 1 (Comparative Example 1),
Then, the same ink as in Example 1 was injected into the ink tank of Comparative Example 2 in which a polypropylene film (75% ultraviolet light extinction ratio) was closely adhered to the ink tank of Example 2, and an ultraviolet irradiation experiment was performed on each ink tank.

The irradiation condition is that the amount of light at 340 nm is 0.3.
The test was performed at 100 and 700 hours (sample temperature 60 ° C.) in a xenon (Xe) lamp test device (SunChex manufactured by Atlas) controlled at 5 W / m ² . Thereafter, the ink in each ink tank was used to perform recording on a copy sheet using a direct plate making machine (SJ02A manufactured by Hitachi Koki). Color difference (ΔE) with a color difference meter (Σ90 made by Nippon Denshoku)
Was measured to determine the change in ink color. The results are shown below.

The inks of Examples 1 and 2 had a small color difference of 5 or less, and there was no large change in the color tone with respect to the initial ink, so they were at a practical level. However, Comparative Examples 1 and 2
It was found that the ink of No. 1 had a large color fading and was not suitable for practical use.

[0024]

[Table 1]

[Example 3, Comparative Example 3] The same ink tank as in Example 2 and a film for dimming ultraviolet rays were attached, and 500 g of ultraviolet curable ink was injected (Example 3). The ink is 20 parts by weight of urethane acrylate (manufactured by Mitsubishi Rayon, trade name: Diabeam UK6038), propylene glycol diacrylate (manufactured by Nippon Kayaku, trade name K
80 parts by weight of AYARAD NPGDA, 3 parts by weight of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals, trade name Irgacure 1700), and 4 parts by weight of a black pigment (manufactured by Mitsubishi Chemical, trade name: MA77) as a colorant, a total of 300 g. A homogenizer (HG30 manufactured by Hitachi Koki) was used to disperse the mixture at a rotation number of 2,000 rpm until a homogeneous mixture was obtained, followed by filtration to remove impurities and the like to obtain a uniform ultraviolet curable ink. Further, for comparison, the same ink was injected into the ink tank of Example 3 in which a film for dimming ultraviolet rays was not adhered (Comparative Example 3), and an ultraviolet irradiation experiment was performed for each. In addition, P. I. I was 5.

The irradiation conditions were tested as in Example 1.
After that, the viscosity of the ink in each ink tank was measured to confirm the progress of curing. The viscosity of the ink was measured with a rotational viscometer (EDL model manufactured by Tokimec). The measurement temperature is 25 ° C. The results are shown below.

The ink of Example 3 shows almost no change in viscosity and the curing reaction by ultraviolet rays has not progressed, whereas the ink of Comparative Example 3 has thickened and thus the curing has proceeded. It turned out to be unsuitable for recording. But,
It has been found that when this ink is used as waste ink, it can be safely discarded because it has been cured.

[0028]

[Table 2]

[0029]

According to the present invention, in the conventional ink containing a dye ink and an ultraviolet curable ink, an ink having high safety and reliability and containing such an ink with good performance, excellent visibility, and unnecessary. It is possible to provide an ink tank with less constituents.

[Brief description of drawings]

FIG. 1 is a perspective view showing an ink tank of the present invention.

[Explanation of symbols]

Reference numeral 1 is an ink tank, 2 is ink, and 3 is an ultraviolet ray blocking film.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tsutomu Maekawa             Hitachiko, 1060 Takeda, Hitachinaka City, Ibaraki Prefecture             Machine Co., Ltd. (72) Inventor Hidetoshi Fujii             Hitachiko, 1060 Takeda, Hitachinaka City, Ibaraki Prefecture             Machine Co., Ltd. (72) Inventor Kunio Sato             Hitachiko, 1060 Takeda, Hitachinaka City, Ibaraki Prefecture             Machine Co., Ltd. (72) Inventor Hitoshi Kida             Hitachiko, 1060 Takeda, Hitachinaka City, Ibaraki Prefecture             Machine Co., Ltd. (72) Inventor Kunihiro Tamahashi             Hitachiko, 1060 Takeda, Hitachinaka City, Ibaraki Prefecture             Machine Co., Ltd. F-term (reference) 2C056 EA19 FC01 FD07                 2H086 BA59 BA60                 3E062 AA09 AB01 AC02 JA01 JA08                       JB22 JC02 JD05                 4J039 AD03 AD21 AE04 AE05 AE06                       AE07 AF03 EA06 GA24

Claims (9)

[Claims] 1. An ink tank characterized in that a film for dimming ultraviolet rays is brought into close contact with an ink tank that contains ink and transmits visible light and ultraviolet rays. 2. The ink tank according to claim 1, wherein an average light transmittance of visible light in 400 to 700 nm is 0.1% or more. 3. The ink tank according to claim 2, wherein the film is a film. 4. The ink tank according to claim 2, wherein the film is a coating film. 5. The ink tank according to claim 3, wherein the film attenuates ultraviolet rays by 80% or more. 6. An ink for an ink jet printer which discharges from a nozzle for recording contains at least an acrylate or methacrylate having a primary skin irritation rate of 6 or less. 7. The ink tank according to claim 1, wherein the ink contains an acrylate or a methacrylate having a primary skin irritation rate of 6 or less. 8. A waste ink is stored by removing a film that attenuates ultraviolet rays from the ink tank.
Ink tank described. 9. The ink tank according to claim 8, wherein the ink tank containing the waste ink is irradiated with ultraviolet rays.