JP2000191965A - Recording of stealth type ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for recording a stealth type ink composition, which can solve insufficient adhesivity, low recording speeds, bad safety, etc., that have been problems on liquid-based ink jet recordings, does not limit recording media, can record at high speeds, and is ecological. SOLUTION: This method for recording a stealth type ink composition comprises thermally liquidizing the stealth type ink composition which is solid at room temperature, and then imparting any jetting energy to the liquidized ink composition to jet the ink composition as ink liquid drops on a recording medium to form recording dots. Therein, the stealth type ink composition does not exhibit remarkable absorption in a visible light region, but emits visible light, when irradiated with UV light. The stealth type ink composition can be jetted at a recording rate of >=10 ips in the travel direction of the recording medium, and does not require any post treatment after the formation of the dots.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recording a stealth ink composition of a luminescent ink whose recording is determined by irradiation with ultraviolet rays, and more particularly to a method for recording a hot melt ink composition used in an ink jet recording apparatus.

[0002]

2. Description of the Related Art It is widely practiced to mark various printed materials, bank checks, envelopes, packages, and the like with bar codes for maintenance and confirmation. In a specific method of this type of marking, a method is used in which printing is performed using a transparent or low-colored ink that cannot be observed with the naked eye, and detection is performed using a specific light beam, that is, ultraviolet light or infrared light, or the like.
For this reason, a special ink called stealth type ink or stealth printing is used.

[0003] With respect to a method of performing this printing using an ink jet recording method, for example, JP-A-51-72509, JP-A-53-140105, JP-A-58-45999, and JP-A-53-55214.
No., JP-A-3-81376, JP-A-6-107992, JP-A-6-297
No. 883, JP-A-7-188599, JP-A-8-239607, JP-A-8
-239609, JP-A-8-253715, JP-A-9-131860, US Pat. No. 5,837,042, US Pat. No. 5,755,860, US Pat. No. 5,366,252, US Pat. No. 5,093,147, and the like.

On the other hand, as the ink composition for ink jet recording, a water-soluble liquid ink composition has been widely used, as can be seen in many of the reports described above.
However, printing on paper where ink tends to soak causes "bleeding", and the recording medium is limited to processed paper. Also, even on recording on a plastic sheet, special treatment was required on the surface due to poor drying properties of the ink. Therefore, as an ink composition that provides good print quality regardless of paper quality, using a hot melt ink composition made of a solid wax or the like at room temperature, liquefied by heating or the like, and adding some energy There has been proposed a hot-melt ink-jet recording system in which a recording dot is formed by jetting, cooling and solidifying while adhering to a recording medium to form recording dots.

A major advantage of this method is that the ink is solid at room temperature and does not stain during handling.
Since the amount of evaporation of the ink during melting can be minimized, nozzle clogging does not occur. Further, since the ink is solidified immediately after the attachment, there is no "bleeding", and various recording media such as Japanese paper, drawing paper, postcards and envelopes can be used without any pretreatment.

For example, JP-A-9-71743, JP-A-9-3377
JP-A-8-165447, U.S. Pat.No. 5,350,789 and U.S. Pat.No.5,703,145 illustrate these hot-melt ink compositions of various compositions, and are described in Japanese Patent No. 2,644,37.
No. 9 uses a luminescent material as one of the image forming agents,
A hot-melt ink composition containing an ionomer component as an essential component is disclosed.

[0007]

However, in the stealth printing, recording media are diversified, and it is necessary to print at a high speed in order to process a large number of printed materials in a short time. The use of ink has caused many fire and environmental pollution problems.

[0008] In addition, for example, in the case of an aqueous solvent ink, which does not cause the above-mentioned problems, a large-sized drying device for drying in a short time is required.
Furthermore, the possibility of damage to the recording medium was unavoidable.

An object of the present invention is to provide a recording method of a stealth type ink composition which can perform high-speed recording, and has high storability and safety, in order to overcome these conventional problems. Another object of the present invention is to optimize the composition and usage of a hot-melt ink composition when applying the composition to the above-mentioned problems.

[0010]

The gist of the present invention to solve the above-mentioned problems is that a solid ink composition is liquefied by heating at room temperature, and then the ink droplets are formed by applying some kind of ejection energy to the recording medium. In the recording method of a stealth type ink composition which is ejected on the top to form recording dots,
The stealth-type ink composition emits visible light when irradiated with ultraviolet light without showing significant absorption in the visible light region, and has a recording speed of 10 ips or more with respect to the traveling direction of the recording medium. The recording method is characterized in that no post-processing is performed after dot formation.

Preferably, the stealth-type ink composition contains a substance that emits visible light upon irradiation with ultraviolet light,
It is preferable to use an ink vehicle having substantially no absorption maximum in the range of 300 to 400 nm.

The stealth type ink composition contains a wax selected from polyethylene wax, microcrystalline wax, paraffin wax, rosin, fatty acid amide, ester or ester amide, polyamide, and ethylene-vinyl acetate copolymer, And it does not contain an ionic polymer.

Further, it is preferable to use an ink vehicle that contains a substance that emits visible light upon irradiation with ultraviolet light and has substantially no absorption maximum in the range of 300 to 400 nm.

[0014]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, various waxes and resins used for hot melt type ink (sometimes called solid ink, solid ink or phase change ink) can be used without any particular limitation. . These include plant waxes such as candelilla wax, carnauba wax, wood wax, animal waxes such as lanolin, paraffin waxes, petroleum waxes such as microcrystalline wax, polyethylene wax, Fischer-Tropish wax, and stearin. Higher saturated or unsaturated fatty acids such as acids and behenic acids, ketones such as stearone and laurone, saturated or unsaturated fatty acid amides, saturated or unsaturated fatty acid esters, glycerides, saturated or unsaturated fatty acid ester amides, saturated or unsaturated aliphatics Alcohol, rosin resin, hydrocarbon resin, amide resin, polyester, polyvinyl acetate, acrylic acid and methacrylic acid polymer, styrene polymer, ethylene vinyl acetate copolymer, polyketone, silicone There the resin is a high molecular weight, such as coumarone.

The hot-melt ink of the present invention can be used in any of various ordinary ink jet discharge methods without any particular limitation.

As a method utilizing the deformation of the piezoelectric (piezo) element, various methods such as a bend mode, a push mode, a shear mode, and a combination thereof can be used.
Also, by appropriately selecting the composition and recording method,
For example, bubble generation (bubble type) ink jet recording described in Patent Publication 2,554,389, US Pat. No. 5,593,486, US Pat. No. 5,151,120 can be performed. Further, continuous (continuous) type ink jet recording described in U.S. Pat. No. 5,821,963 can be performed.

The melt viscosity of the ink composition of the present invention is 5 to 5
0 mPa · s, preferably 5 to 30 mPa · s. 5mPa ・
If the viscosity is less than s, the sedimentation of the luminous body cannot be prevented, and 50 mPa · s
If the viscosity exceeds, it is difficult to perform ink jet recording.

The heating temperature is preferably 70 ° C. or higher,
Preferably it is 100-150 degreeC. In the case of ink having a low viscosity at a melting temperature lower than 70 ° C., sufficient mechanical strength cannot be secured when left at room temperature, and an excessive load on the apparatus is required to maintain a temperature higher than 150 ° C.

In the present invention, a luminescent substance which emits ultraviolet light may be used. This includes fluorescent and phosphorescent materials, such as U.S. Pat. No. 5,755,860, U.S. Pat.
Various light-emitting materials disclosed in US Pat. No. 7,042, US Pat. No. 5,256,139 can be used without any particular limitation.

Acryflavin, a fluorescein-based or rhodamine-based fluorescent dye used for a laser dye or the like;
The Society of Dyers and Colorants, edited by “Color In
In "dex", coloring materials classified as Fluorescent Brighteners (fluorescent brighteners) can be suitably used. These include stilbene, thiazole, coumarin, naphthothiazole, triazole, xanthene, and naphthalimide-based coloring materials. , Triazine, morpholine, pyrazolone, azole, oxazole, azacyanine,
There are various compounds such as pyrazoline, acenaphthene, benzimidazole and benzoxazole.

Further, rare earth elements and their organic chelate complexes used as light emitters of CRTs and the like are also suitably used for the purpose of the present invention. As rare earths, Sc, Y, La,
Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, D
There are y, Ho, Er, Tm, Yb, and Lu. Further, as an element which emits light by forming a complex, Al, B, Be,
Representative examples include Cd, Ga, Li, Mg, Mo, Sb, U, W, and Zr.

The ring-opening and cyclic chelating ligands used in the complex include alkylpolyamines, 2,2′-bipyridines,
1,10-phenanthroline, aromatic polyamine, amino alcohol, amino acid, peptide, polyaminopolycarboxylic acid, 1,3-diketone, oxime, Schiff base, phenol, 1,2-dithiolene System, dithioorbamine system, xanthogenic acid system, dithiocarboxylic acid system,
There are thiol type, phosphine, arsine, selenide type, saturated and unsaturated cyclic polyamine type, porphyrin type, phthalocyanine type, borane type, carborane type and the like.

Specifically, acetylacetone, morin, oxine, pontachrome blue black R, flavonol, amino-4-hydroxyanthraquinone, benzoin, cochineal, quinizarin, 2-methyloxin,
2-hydroxyphenyl-benzoxazole, eriochrome red B, superchrome garnet Y, eriochrome red B, rhodamine B, 5,7-dichlorooxin, 5,7-dibromoxin, benzoylacetone,
Examples include dibenzoylacetone, salicylic acid, and dibenzoylmethane.

As these metal complexes, there can be used, for example, the compounds described in the Chemical Chemistry Course, Vol. 17 and 18, edited by The Chemical Society of Japan, Maruzen (published in 1991). Fluorescence or EL (electroluminescence)
Powders, for example, Y ₂ O ₃ S: Eu, ZnS: Cu: Al, Z
nS: Ag, ZnO: Zn, (ZnCd) S: Ag, Z
nS: Mn: Cu, ZnS: Cu, ZnB: Cu and the like can also be used.

Specific examples of the luminescent agent include coumarin-based photosensitizers NKX-846, 1297, 1319, 1595, 1858, and 125.
3, 1658, ketocoumarin-based NKX-653, 1792, 1880, styryl-based NK-1819, 1886, 3390, dicyanomethylene (D
CM) NK-1473, 1474, cyanine NK-2911, 4432, 448
9, NKX-1317, 1318, 1316, 176 which are dyes for laser oscillation
7, 1768, 1320, 1769, 1319, 1770, 1771 (all manufactured by Japan Photographic Dye Laboratories), PBB which is a general name of fluorescent agent
O, BBOT, BBO, DPH, PPO, DPS, PBD, POPOP, TPB, butyl-PBD, α-NPO, p-terphenyl, p-quarterphenyl (manufactured by Dojin Chemical or Wako Pure Chemical), EB-501, G-502, ER-
120 (Mitsui Chemicals), LUMILUX-C, RedCD105, RedCD10
6, RedCD120, RedCD131, RedCD316, RedCD331, RedCD33
2, RedCD335, RedCD339 (Made by Clariant), CALCO
FLUOR WHITE LD, CALCOFLUOR WHITE RAP, CALCOFLUOR W
HITE RW (above made by BASF), UVITEX-OB (made by Ciba Specialty Chemical), Eu (TTA) ₃ Phen (made by Dojinato), ULTR
APHOR RN LIQUID (made by Mitsui-BASF dye) and the like.

In the recording method of the present invention, a so-called post-processing step in which heating, pressurization, and electromagnetic radiation (ultraviolet rays, infrared rays, electron beams, microwaves, etc.) are usually used for ink treatment after the recording step. Not use high speed recording,
It is desirable in terms of low power operation. That is, the dots recorded by the inkjet can be used without any processing.

The present invention is effective only when the printing speed is high. In particular, 10 ips (inch / inch)
Seconds) or more. In a recording method having a post-process or a recording speed of less than 10 ips, the features of the present invention are not fully utilized. For this purpose, the stealth ink composition and the recording method of the present invention are:
It is particularly preferable to use a line-type head and a recording method, that is, a recording method that does not move back and forth in the direction perpendicular to the traveling direction (shuttle type).

The excitation wavelength for reading the stealth recording of the present invention is not particularly limited, and many electromagnetic rays including electron beams, X-rays and particle beams can be used. Preferably, light is used. If the wavelength is less than 300 nm, the absorption of the hot melt type ink material tends to be excessive, and it is not possible to effectively utilize ultraviolet light for light emission. If the wavelength exceeds 400 nm, the ink must be absorbed in the visible light region to excite the ink, which is unsuitable for coloring purposes.

As a light source, a deuterium lamp, a xenon lamp, a halogen lamp,
Light sources such as low-pressure, high-pressure and ultra-high-pressure mercury lamps, mercury xenon lamps, hollow cathode lamps,
As a metal halide lamp and a pulse light source, a xenon flash lamp, a nitrogen laser, an excimer laser and the like can be used.

The emission wavelength is appropriately selected from infrared light, near-infrared light, visible light, and the like according to the characteristics of the sensing element or device. In particular, visible light, that is, a wavelength of 400 to 750 nm is used. Is preferred. In a region outside this wavelength range, special consideration is required for the detection element or device. In the visible light range, various wavelengths such as blue, green, orange, red, and yellow, and mixtures and intermediate colors thereof are detected according to the purpose.

As described above, various waxes can be used in the stealth type ink composition of the present invention without limitation.
In particular, an ink composition having substantially no absorption maximum in the range of 300 to 400 nm, especially polyethylene wax,
Microcrystalline wax, paraffin wax,
Rosin, fatty acid amide, ester or ester amide,
It is desirable to contain a wax selected from polyamide and ethylene-vinyl acetate copolymer.

Although it is not clear why these materials exhibit particularly suitable characteristics, (1) a transparent and uniform ink composition is formed so that light absorption and scattering hardly occur in the visible region.
(2) It has an appropriate glass transition point (softening point), melting point (flow initiation temperature), and surface tension (surface energy, contact angle), and can perform good recording on many recording media.
Since the compatibility with the luminescent material and the dispersibility were good and the compatibility between the components was excellent, items such as good transparency were recognized.

If the softening temperature is inappropriate, for example, if the temperature is too low, unnecessary penetration into the recording medium such as paper may occur, or if the temperature is too high, the solidification is rapid and the ink dots do not adhere to the recording medium. Causes malfunction. Also,
(4) These waxes are all aliphatic organic compounds, and have a common feature that they do not have an absorption maximum at 300 to 400 nm based on a π-electron conjugate system like aromatic compounds.

On the other hand, ionic polymers such as ethylene-
A methacrylic acid copolymer or the like is not preferable because, in practical use, it tends to cause a problem in water resistance, and a metal ion component serving as a counter ion of free ions tends to cause electrochemical problems such as corrosion to an inkjet head portion. In particular, since it is difficult to make the various waxes described above compatible with each other due to the difference in ionicity, serious problems are likely to occur in the production of a uniform ink composition. It is not preferable to mix and use the components of the present invention.

Polyethylene wax is obtained by polymerization of ethylene,
It is obtained by separation, decomposition and oxidation from polyethylene, and various types of high density, medium density and low density having a molecular weight of 1,000 to 10,000 are used. Specifically, Mitsui High Wax (manufactured by Mitsui Chemicals), A-wax (manufactured by BASF),
AC-polyethylene (Allied-Signal), Hoechst wax (Hoechst), Baleco wax (Baleco), Epolen (Eastman Chemical), Sun wax (Sanyo Chemical), Sasol wax (Sazole), polywax ( Petrolite).

Microcrystalline wax and paraffin wax are petroleum waxes made from components separated during petroleum refining, and are mixtures of hydrocarbons having about 19 to 70 carbon atoms. There are Nisseki Microwax (Nisseki Chemical), Mobile Wax (manufactured by Mobile), Hi-Mic (Nippon Seisaku) and others. For example, as paraffin wax, HNP-3, 5, 9, 10, 11, 12, 14G, SP-0160, 014
5, 1040, 1035, 3040, 3035 (all made by Nippon Seisaku), Hi-Mic-2095, 3090, 1 as microcrystalline wax
080, 1070, 2065, 1045, 2045 (all made by Nippon Seiwa).

Rosin is a natural resin mainly made of pine tar, and includes gum rosin, wood rosin, tall oil rosin and the like, and its main components are fatty acids such as abietic acid and esters. Pinecrystal KE100 (Arakawa Chemical), DS-110S
(Made by Harima Chemicals).

As fatty acid amides, monoamides, bisamides, tetramids and the like are used. For example, lauric acid amide, stearic acid amide, oleic acid amide, erucic acid amide, ricinoleic acid amide, stearic acid ester amide, palmitic acid amide, behenic acid amide, brassic acid amide, etc., as N-substituted fatty acid amides,
N, N'-2-hydroxystearic acid amide, N, N'-ethylenebisoleic acid amide, N, N'-xylenebisstearic acid amide, stearic acid monomethylolamide,
N-oleyl stearamide, N-stearyl stearamide, N-oleyl palmitamide, N-stearyl erucamide, N, N′-dioleyl adipamide, N, N′-dioleyl sebacamide, N, M´
-Distearyl isophthalic acid amide, 2-stearamidethyl stearate and the like are selected. Particularly, fatty acid alkylamides are preferably used. Fatty acid amides are 10
The melt viscosity around 0 ° C. is low, and the effect of lowering the melting point of the ink and lowering the viscosity during melting is remarkable.

As the fatty acid ester, a monohydric or polyhydric alcohol fatty acid ester is desirable. For example, sorbitan monopalmitate, sorbitan monostearate, sorbitan monobehenate, polyethylene glycol monostearate, polyethylene glycol distearate, propylene glycol monostearate, ethylene glycol distearate, pentaerythritol tristearate, dipentaerythritol Behenic acid full ester, behenyl behenate, and the like are selected.

As the fatty acid ester of glycerin, for example, stearic acid monoglyceride, palmitic monoglyceride, oleic acid monoglyceride, behenic acid monoglyceride and the like are selected. Higher alcohol esters of higher fatty acids such as myricyl cerotate, ceryl citrate, ceryl montanate, myricyl palmitate, myricyl stearate, cetyl palmitate and cetyl stearate are also selected. Specifically, Reodor Doll SP
-S10, Reodol SP-S30, Reodol SSA10, Emazole P-10, Emazole S-10, Emazole S-20, Emazole B, Rheodol Super SP-S10, Emanone 3199,
Emanone 3299, Exepearl PE-MS (Kao) and the like can be used.

Even more preferred are fatty acid esters of glycerin. For example, stearic acid monoglyceride, palmitic monoglyceride, oleic acid monoglyceride, behenic acid monoglyceride and the like are selected. Specifically, Reodol MS-50, Reodol MS-6
0, Reodol MS-165, Reodol MO-60, Exepearl G-MB (Kao), deodorized purified carnauba wax No. 1, Purified candelilla wax No. 1 (Noda wax), Synchro wax ERL-C, Synchro wax HR-C (Kuroda), KF2 (Kawaken Fine Chemical), Elektor WEC
-5, Elektor WEP-4, Elektor WEC-2 (Nippon Oil & Fats), Unistar H476, H476D, H422, H622S, M2222S
L, M9676 (Nippon Yushi) can be used. Exepearl DS-C2 (Kao), Kawaslip-L, Kawaslip-R (Kawaken Fine Chemical), etc. are also selected as special ester waxes. Higher alcohol esters of higher fatty acids such as myricyl cerotate, ceryl citrate, ceryl montanate, myricyl palmitate, myricyl stearate, cetyl palmitate and cetyl stearate are also selected. In addition to the stable fluidity during ink melting,
Fatty acid esters have low melt viscosity and stable fluidity when ink is melted.
Compared with the bonding of carbon, since it has high flexibility and strong surface protection, it can withstand bending of a printed image. Further, those having a viscosity of less than 20 mPa · s during injection are suitable.

Examples of the fatty acid ester amide include Kawaslip SA (manufactured by Kawaken Fine Chemical), CPH-380N
(Manufactured by CP Hall) is selected.

The polyamides are particularly preferably dimer (dimer) acid-based polyamides. Optimally, the base acid is oleic, linoleic, linoleic or eleostearic acid. Specifically, amide resins such as Versamide 711 and Versamide 72
5, Versamide 930, Versamide 940, Bar Salon 1117,
Bar Salon 1138, Bar Salon 1300 (made by Henkel),
Tomide 391, tomide 393, tomide 394, tomide 395, tomide 397, tomide 509, tomide 535, tomide 558, tomide 560, tomide 131
0, Tomide 1396, Tomide 90, Tomide 92 (Made by Fuji Kasei), KTR2150 (Made by Kao) as polyester, Macromelt 6030, Macromelt 6065, Macromelt
6071, Macromelt 6212, Macromelt 6217, Macromelt 62
24, Macromelt 6228, Macromelt 238, Macromelt 623
9, Macromelt 6240, Macromelt 6301, Macromelt 690
0, DPX 335-10, DPX H-415, DPX 335-11, DPX 830, DPX
850, DPX 925, DPX 927, DPX 1160, DPX 1163, DPX 11
75, DPX 1196, DPX 1358 (Henkel Hakusui), SYLVAMID E-
5 (Arizona Chemical), UNIREZ 2224, UNIREZ 2970
(Union camp), AC401, A as polyvinyl acetate
C540, AC580 (all made by Allied Chemical) can be used.

As the vehicle, at least one kind selected from these, or a mixture of two or more kinds can be used. All of these have good wettability to a recording medium and exhibit high adhesive performance. Further, it has excellent adhesion to a wide variety of adherend substances.

The appropriate amount of the compound which emits light upon irradiation with ultraviolet rays is 0.01 to 5% by weight based on the total amount of the ink. Particularly desirable is 2% by weight or less. 0.01
When the amount is less than 5% by weight, the emission intensity is reduced. When the amount is more than 5% by weight, the recording becomes exposed during non-irradiation due to coloring or the like, and adversely affects the viscosity characteristics of the ink. Various surface treating agents, surfactants, viscosity reducing agents, antioxidants, antioxidants, antioxidants, crosslinking accelerators, ultraviolet absorbers, plasticizers, preservatives for further developing functionality in the ink composition of the present invention. , A dispersant, a pigment, a dye and the like can be mixed.

The preparation of high quality ink jet inks requires a balance of many important factors. The ink of the present invention satisfies several well-known requirements for application to hot melt inkjet printers. That is, the ink has sufficient hardness and stability at room temperature, and has high reliability in storage before printing and image quality after printing. After attaching to a recording medium, it has sufficient transparency and saturation, and forms a uniform thin film to give a printed matter of good image quality. While these requirements are complex and cannot always be clearly quantified for the inks of the present invention, for example, hot melt inks with relatively low melting points are typically susceptible to bleed and offset. Even when stored at 40 ° C., it is necessary that offset does not occur in a state where printed matters are stacked. However, the higher the melting point of the ink, the higher the viscosity,
The melt viscosity at the time of printing is 50 mPa · s or less, especially 5 to 3
A range of 0 mPa · s is desirable on the apparatus. Excessive viscosities require more energy at the time of injection, and materials with too low viscosities cause problems in storage stability at room temperature. The viscosity at room temperature (25 ° C.) is 10,000 Pa · s or more.

As for the bending characteristics of the printed material, it is desirable that the test pass a test of 5 mmφ or less, particularly 3 mmφ or less in a mandrel test using a plastic film.
The temperature at which the ink is melted during printing is optimally in the range of 100 to 150 ° C. in order to make the apparatus simple and inexpensive. The surface tension at the time of melting is desirably 40 mN / m or less. It is desirable that the volume change upon transition from the molten state to the solid be 10% or less.

The stealth type ink composition and recording method of the present invention can be applied to conventionally known ink jet printers, such as office printers and industrial markings, by ejecting ink droplets only when printing is required (on-demand type). It can be used for printers used, wide format printers, printing and plate making printers, label printers and all types of printers having this typical operation. Examples of the recording medium include paper, plastic films, capsules, gels, metal foils, cloths, and the like. Absent. A method of once recording on a transfer body and transferring it to a recording medium, and a recording method including a process such as a pressurizing and heating device can also be used.

Further, the composition and the recording method can be used for many well-known industrial ink jet printers and marking devices as particularly suitable applications. These include a wide variety of articles and their packaging, containers, packs, including sheets and bulk of ordinary media, i.e., paper, treated paper, high quality paper, plastic, metal, fabric, glass, etc.
It can be used for marking on bottles and bags, for example, beverages such as juice and beer, food products such as dairy products and breads, cosmetics such as shampoos and detergents, pharmaceuticals, chemicals, and electric / electronic devices. In addition, cards, label making devices, pillow wrapping machines, postal address sorting device marking, postal code printing machines,
It can be used for business card making machines, securities such as bank checks, important documents, etc., markings on paintings, monuments, cultural properties, etc., and direct mail making devices. Various printing or processing apparatuses combining the ink composition and the recording method apparatus of the present invention with an exposure apparatus and a detection apparatus are also possible.

Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to the examples. [Example 1] Esteramide (CP Hall) as a vehicle
(Product name: CPH380N), 20 parts by weight of ester wax (manufactured by Nippon Oil & Fat: UNISTAR H476), 28 parts by weight, and 12 parts of polyethylene wax (manufactured by Nippon Seisen: WEISSEN 252C).
Parts by weight, microcrystalline wax (made by Nippon Seiwa:
Hi-Mic 1070), 10 parts by weight, rosin (Arakawa Chemical: Pin)
A total of 400 g of a mixture containing 30 parts by weight of ecrystal KE100) and 0.01 part by weight of a blue light-emitting material (manufactured by Ciba Specialty Chemicals: UVITEX-OB) is heated and kneaded at 130 ° C. until a homogeneous molten mixture is obtained (approx. 5 hours)
Subsequently, heat and pressure filtration was performed to remove impurities and the like, and the mixture was allowed to cool at room temperature to obtain a homogeneous hot melt ink composition.

On the other hand, for comparison, a comparative composition was prepared by the same composition and kneading step except for the luminescent agent alone. These ink compositions do not exhibit substantially strong light absorption in the visible region. In addition, the comparative composition is not only in the visible range, but also in the 300 range.
It did not show substantially strong absorption in the ultraviolet region of 400 nm.

The ink composition thus prepared was heated and melted at 130 ° C., and the melt viscosity was measured using a rotational viscometer (EDL model manufactured by Tokimec). The average value measured five times is 13.1 mP
a · s was indicated. Use this ink as a solid inkjet printer (manufactured by Hitachi Koki: Direct printing plate printer SJ02A)
The test pattern was printed on plain paper (Xerox 4024 paper) in a high-speed printing test apparatus (600 dpi resolution) using a piezoelectric element push mode head portion of the above. The printing speed (paper running speed) varied in the range of 10 to 200 ips, but in all cases, the printing condition was good and exhibited abrasion resistance immediately after printing, and penetration into paper, peeling, light scattering, and other defects. Was not observed at all.

Immediately after printing, when a black lamp (made by UVP: Model UVM-57) was irradiated with ultraviolet rays, good green-yellow light emission was observed. This printed matter did not substantially absorb or scatter in the visible light range, and was difficult to visually observe unless irradiated with ultraviolet light. Example 2 76 parts by weight of ester amide (manufactured by Kawaken Fine Chemicals: Kawaslip SA), 4 parts by weight of polyamide (manufactured by Henkel Hakusui: DPX-H415) as a vehicle, Pine
A total of 50 parts of a mixture containing 20 parts by weight of crystal KE100 and 0.1 and 0.01 parts by weight of a red light-emitting agent (manufactured by Mitsui Chemicals: ER-120) or a blue light-emitting agent (manufactured by Mitsui Chemicals: EB-501), respectively.
0 g was heated and kneaded until a homogeneous molten mixture was obtained (about 3 hours), followed by filtration under heat and pressure to remove impurities and the like, and allowed to cool at room temperature to obtain a homogeneous hot melt ink composition. .

Further, in the same manner as in Example 1, a comparative mixture was prepared in the same manner as in Example 1 except that no luminescent agent was added.

The ink composition and the comparative mixture were heated to 130 ° C., and the melt viscosity was measured using a rotational viscometer. The average value measured five times was 7.9 mPa · s. The ink composition does not substantially exhibit strong absorption and scattering in the visible region, and the comparative mixture has a viscosity of 300 to 4 in addition to the visible region.
No strong absorption was shown in the region of 00 nm.

The ink composition was placed in an ink jet printer test apparatus in the same manner as in Example 1 and left in a molten state for 3 days to perform jetting. It was confirmed that all the inks were jetted without any problem. The printing speed was changed in the range of 10 to 200 ips, and plain paper, treated paper (manufactured by Seiko Epson: superfine paper for inkjet), and PVC coated sheet (manufactured by Ewa Shoko: BPV-01-T) were used as substrates. Under any of the conditions, the printing condition was good and the abrasion resistance was exhibited immediately after printing, and no permeation to the substrate, peeling, light scattering, and other defects were observed at all.

When irradiated with ultraviolet rays in the same manner as in Example 1,
Clear red-orange and blue luminescence were observed in all of the printed samples. These printed materials did not show substantial absorption or scattering in the visible light region, and were difficult to visually observe unless irradiated with ultraviolet light. [Example 3] Ester wax (manufactured by Celarica Noda: Candelilla wax No. 1) and EVA copolymer (manufactured by Nippon Seiwa: Polycoat 3030) were used as vehicles, respectively.
A total of 500 g of a mixture containing 0.1 parts by weight of a red luminescent agent (manufactured by Dojindo Chemical: Chelate Complex Eu (TTA) ₃ Phen) at 130 ° C. was heated at 130 ° C. until a homogeneous molten mixture was obtained. The mixture was kneaded, followed by filtration under heating and pressure to remove impurities and the like, and allowed to cool at room temperature to obtain a homogeneous hot melt ink composition.

This ink composition was heated to 130 ° C., and the melt viscosity was measured with a rotational viscometer in the same manner as in Example 1. The average value measured five times showed 5 mPa · s.

The above ink composition was placed in the same test apparatus as in Example 1, and a test pattern was printed on plain paper. This printed matter did not substantially absorb or scatter in the visible light range, and was difficult to visually observe unless irradiated with ultraviolet light. Example 4 Ester wax (Deodorized and refined carnauba wax No. 1 manufactured by Cerarika Noda) and aliphatic amide (Kemamide S-180 manufactured by Witco) were each used as a vehicle.
A total of 500 g of a mixture containing 5 parts by weight, 45 parts by weight and 2 parts by weight of a red light-emitting agent (manufactured by Nilaco: red phosphor Y ₂ O ₃ S: Eu) was stirred at 140 ° C. by a stirring mill (manufactured by Kurimoto Iron Works). The mixture was heated and kneaded (about 6 hours) until a homogeneous molten mixture was obtained, followed by filtration under heating and pressure to remove impurities and the like, and was allowed to cool at room temperature to obtain a homogeneous hot melt ink composition.

This hot melt ink composition was heated to 130 ° C.
, And the melt viscosity was measured using a rotational viscometer in the same manner as in Example 1. The measurement was performed five times, and the average value was 30 mPa · s.

The ink composition was placed in a test apparatus in the same manner as in Example 1 and printing was performed, and it was confirmed that red light was satisfactorily emitted by ultraviolet irradiation with black light. This printed matter did not substantially absorb or scatter in the visible light range, and was difficult to visually observe unless irradiated with ultraviolet light. Example 5 Each of 20, 40, and 40 parts by weight of paraffin wax (manufactured by Nippon Seisaku: HNP-9), polyethylene wax (manufactured by Mitsui Chemicals: HW110P), and ester wax (manufactured by NOF Corporation: Unistar M2222SL) as vehicles. Two kinds of mixed compositions were prepared by mixing 0.1 part by weight of each of a green luminescent agent (manufactured by Mitsui Chemicals: EG-502) or a red luminescent agent (manufactured by Clariant: LUMILUX CD331). A total of 500 g of the mixed composition was heated at 130 ° C. using a motor mill (manufactured by Eiger Japan).
The mixture was heated and kneaded until a homogeneous molten mixture was obtained, followed by filtration under heating and pressure to remove impurities and the like, and allowed to cool at room temperature to obtain two homogeneous hot melt ink compositions.

The melt viscosity of these hot melt ink compositions was measured at 130 ° C. in the same manner as in Example 1.
16 and 17 mPa · s were obtained in this order.

This ink composition was placed in a test apparatus in the same manner as in Example 1 and printing was performed, and it was confirmed that green or red light was satisfactorily emitted by ultraviolet irradiation with a black light.
These printed materials did not show substantial absorption or scattering in the visible light region, and were difficult to visually observe unless irradiated with ultraviolet light. [Comparative Example 1] 3 parts by weight of ZnS: Cu: Al (manufactured by Nilaco) as a luminescent agent, and a dispersant (manufactured by Kao: Emulgen A-90)
5 parts by weight, resin content (manufactured by Nippon Polymer: W-251: solid content 4
(0% acrylic resin emulsion) 0.3 parts by weight, 0.1 parts by weight of monoethanolamine, 10 parts by weight of diethylaminoethanol, 0.03 parts by weight of EDTA and 85 parts by weight of ion-exchanged water are dispersed until a homogeneous dispersion solution is obtained. ,
The mixture was kneaded, followed by filtration to remove impurities and the like, thereby obtaining an ink composition. This ink composition exhibited a viscosity of 4.5 mPa · s.

The ink composition was placed in a test apparatus in the same manner as in Example 1 and printed on plain paper without heating. After drying, it was confirmed that the ink composition emitted green light when irradiated with ultraviolet light using black light. However, since the drying of the ink composition was remarkably slow, the printed portion did not exhibit resistance to rubbing, and it took several minutes even with hot air drying (80 ° C.) to obtain a usable state. When the heating and drying process was not used, several hours were required. Comparative Example 2 0.1 parts by weight of UVITEX-OB as in Example 1 was mixed with dipropylene glycol methyl ether (manufactured by Dow Chemical: Dowanol DPM) as a luminescent agent, and the mixture was stirred until a homogeneous dispersion solution was obtained. Subsequently, filtration was performed to remove impurities and the like, thereby obtaining an ink composition. This ink composition had a viscosity of 3.8 mPa · s.

This ink composition was placed in a test apparatus in the same manner as in Example 1, and printing was performed on plain paper without heating, and it was confirmed that the ink composition emitted green light when irradiated with ultraviolet light using black light. However, since the drying of the printed portion is extremely slow, the printed portion bleeds due to penetration into the paper, and it took several minutes even with hot air drying (80 ° C.) to exhibit resistance to rubbing. When the heating and drying process was not used, several hours were required. [Comparative Example 3] Ionic polymer (manufactured by Dupont: Surlyn) and ester wax (manufactured by Cerarika Noda:
20 and 80 parts by weight of each of the deodorized and purified carnauba wax No. 1) and 0.1% of UVITEX-OB as in Example 1 were added.
% By weight and 130 ° C. until a homogeneous dispersion is obtained.
, Followed by filtration to remove impurities and the like to obtain a hot melt ink composition. These hot melt ink compositions were measured for melt viscosity at 130 ° C. in the same manner as in Example 1 to obtain 20 mPa · s.

These compositions remained a cloudy mixture with poor compatibility of the components. Printing was attempted in a test apparatus in the same manner as in Example 1. However, poor nozzle quality was caused due to non-uniform dot printing, resulting in poor quality and insufficient abrasion resistance.

[0067]

The stealth-type ink composition and the recording method of the present invention solve problems such as insufficient adhesion to a recording medium, low recording speed, and safety, which have conventionally been problems in the case of liquid ink-jet recording. Thus, it is possible to provide an ink composition and a recording method which can record at a high speed without limiting the recording medium and which is environmentally friendly.

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Claims (3)

[Claims] 1. A stealth-type ink composition that forms a recording dot by liquefying an ink composition that is solid at room temperature by heating and then applying some ejection energy to eject ink droplets onto a recording medium. In the recording method, the stealth-type ink composition emits visible light when irradiated with ultraviolet light without showing significant absorption in the visible light region, and the recording speed of the recording medium progresses. A method for recording a stealth-type ink composition, wherein the direction is 10 ips or more, and no post-processing is performed after dot formation. 2. The recording method for a stealth ink composition according to claim 1, wherein the stealth ink composition contains a substance that emits visible light upon irradiation with ultraviolet light, and is substantially 300 to 40.
A recording method for a stealth-type ink composition, comprising using an ink vehicle having no absorption maximum in a range of 0 nm. 3. The method for recording a stealth ink composition according to claim 1, wherein the stealth ink composition is a polyethylene wax.
Microcrystalline wax, paraffin wax,
Rosin, fatty acid amide, ester or ester amide,
A method for recording a stealth-type ink composition, comprising a wax selected from a polyamide and an ethylene-vinyl acetate copolymer and containing no ionic polymer.