JP3123128B2 - Ink for inkjet printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink used for an ink jet recording apparatus for forming characters and images on a transfer medium such as recording paper by flying ink droplets.

[0002]

2. Description of the Related Art Conventionally, ink jet recording systems can be roughly classified into two types, a continuous type and an on-demand type. As an ink used in such an ink jet system, an ink in which a dye is dissolved in water occupies the mainstream (hereinafter referred to as an aqueous ink). As the aqueous ink, those obtained by dissolving various water-soluble dyes in water or a solvent composed of water and a water-soluble organic solvent and adding various additives as necessary are currently used. The advantages of these ink jet recordings are that the process is simple because they are direct recordings, they are noise-free because they are not impact systems, they are easy to colorize, they are capable of high-speed recording, and they can use plain paper. Low running cost,
It has excellent features such as high-resolution recording for discharging minute ink droplets, and its future is attracting attention.

[0003]

However, in the above-mentioned prior art, although slightly different depending on the method, the common technical problem is that: 1 ink bleeds on the recording paper, and a high-quality recorded image cannot be obtained.

2 Drying of the ink on the recording paper is slow, and tailing occurs.

[0005] (3) The nozzles and the ink supply path are clogged, and the ink ejection is not stable.

[0006] (4) Since the abrasion resistance of the ink on the recording paper is poor, there is no storability of the recorded image.

And the like.

Attempts have also been made to solve the above problems. For example, Japanese Patent Publication No. 55-29546 discloses a method of adding a specific surfactant to lower the surface tension to form an ink on recording paper. Japanese Patent Publication No. 56-57862 discloses a method of increasing the pH by adding a strong basic substance and chemically converting a sizing agent or a pulp agent, which is a water-resistant treatment agent for plain paper, into a paper. A method for controlling the spread and absorption of dots by dissolving in water has been reported. Japanese Patent Publication No. 58-13675 discloses a method in which polyvinylpyrrolidone having a molecular weight of 40,000 or more is put into an ink, and the spread of dots and recording paper are controlled. Methods have been proposed to control the absorbency to water, but these attempts solve some of the problems described above, but do not provide solutions to all of the problems.

Accordingly, an object of the present invention is to provide an ink for an ink jet printer which is free from bleeding on recording paper, has excellent print drying properties, has no nozzle clogging, and has excellent scratch resistance. .

[0010]

The ink for an ink jet printer according to the present invention is characterized in that colored resin particles are dispersed in a dispersion medium which is a non-polar insulating solvent.

[0011]

Embodiments of the present invention will be described below in detail.

The method for producing the ink for an ink jet printer of the present invention will be described below. A predetermined amount of pigment is added to the place where the resin is heated to make it soft, and the resin is colored by kneading with three rolls while heating. At this time, a dye may be added in order to enhance the coloring property. Crush this,
After adjusting the particle size, the particles are dispersed in a dispersion medium which is a non-polar insulating solvent. In addition, a dispersant is added as needed at the time of dispersion. The method for producing the ink of the present invention is not limited to this.

The resins usable in the present invention include, for example, phenol resins, amino resins (urea resins, melamine resins), diallyl phthalate resins, epoxy resins, unsaturated polyester resins, silicone resins, polyurethanes, polyimides, BT resins , Polyamide imide, high density polyethylene, ultra high molecular weight polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionomer resin, polymethylpentene, polystyrene, AB
S resin, AS resin, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl formal, methacrylic resin, fluororesin, polycarbonate, polyacetal,
Nylon 6, 6-6, flexible nylon, aromatic polyamide (aramid), PET, PBT, modified PPO, polyphenylene sulfide, polysulfone, polyether sulfone, polyether ether ketone, polyarylate,
Aromatic polyester (econol), cellulose acetate,
Polyvinyl acetate / cellulose acetate butyrate, styrene-maleic acid copolymer, benzyl sulfose, ethyl cellulose, natural rubber, nitrocellulose, ketone resin, polymethyl methacrylate, polyamide resin,
Acrylonitrile-styrene copolymer, vinylidene chloride-acrylonitrile copolymer, hydroxypropyl cellulose, vinyl chloride-vinyl acetate copolymer, shellac,
There are vinyl chloride-vinyl acetate copolymer, polyester, polyacrylate, cellulose acetate propionate, cellulose acetate butylate, polyvinylpyrrolidone, vinyl acetate butyl copolymer, hydroxypropylmethylcellulose phthalate, polyurea and the like. The required characteristics may be any resin that is insoluble in a non-polar insulating solvent, and a resin suitable for the above-described production method is preferably thermoplastic.

The pigment used for coloring the resin in the present invention is not particularly limited. For black and white, for example, carbon blacks such as furnace black, lamp black, acetylene black, and channel black, or copper, Examples thereof include metals such as iron and titanium oxide, metal oxides, and organic pigments such as orthonitroaniline black. For colors, Toluidine Red, Permanent Carmine FB, Fast Yellow AA
A, Disazo Orange PMP, Lake Red C, Brilliant Carmine 6B, Phthalocyanine Blue, Quinacridone Red, Dioxane Violet, Pictoria Pure Blue, Alkaline Blue Toner, First Yellow 10G, Disazo Yellow AMX, Disazo Yellow AA
OT, disazo yellow AOAA, yellow iron oxide, disazo yellow HR, orthonitroaniline orange, dinitroaniline orange, vulcan orange, toluidine red, chlorinated para red, brilliant fast scarlet, naphthol red 23, pyrazolone red, barium red 2B, calcium red 2B, Strontium Red 2B, Manganese Red 2B, Barium Lysome Red, Pigment Scar Red 3B Lake, Lake Bordeaux 10B, Ansosine 3B Lake, Ansosine 5
B Lake, Rhodamine 6G Lake, Eosin Lake, Bengala, Phthol Red FGR, Rhodamine B Lake, Methyl Bio Red Lake, Dioxazine Bio Red, Basic Blue 5B Lake, Basic Blue 6G Lake, Fast Sky Blue, Alkaline Blue R
Toner, Peacock Blue Lake, Navy Blue, Ultramarine Blue, Reflex Blue 2G, Reflex Blue R, Brilliant Green Lake, Diamond Green Thioflavin Lake, Phthalocyanine Green G, Green Gold, Phthalocyanine Green Y, Iron Oxide Powder, Sabiko, Zinc Flower , Titanium oxide, calcium carbonate, clay, barium sulfate, alumina white, aluminum powder, bronze powder, daylight fluorescent pigment, pearl pigment, naphthol carmine FB, naphthol red M, permanent carmine F
B, Fastero G, Disazo Yellow AAA, Disazo Orange PMP, Lake Red C, Dioxane Bio Red, Alkaline Blue G toner, and other processed pigments such as graft carbon whose pigment surface is treated with a resin or the like can be used. The addition amount is preferably 1 to 30% by weight,
Further, the content is preferably 3 to 12% by weight. A pigment having a particle size of 25 μm or less is used. Further, from the viewpoint of high printing quality, storage stability, and difficulty in clogging at a discharge nozzle, 0.1
It is preferable to use a pigment composed of particles having a size of 5 μm or less.

In the present invention, the dye to be added to enhance the color development of the resin particles can be selected from the following dyes. For example, acridine dye, aniline black dye, anthraquinone dye, azine dye, azomethine dye, benzo- and naphthoquinone dye, indigoid dye, indophenol dye, indoaniline dye, indamine dye, leuco dye, naphthalimide dye, nigrosine dye, indulin dye, nitro And dyes such as nitroso dyes, oxazine and dioxazine dyes, oxidation dyes, phthalocyanine dyes, polymethine dyes, quinophthalone dyes, sulfur dyes, tri- and diacrylmethane dyes, thiazine dyes, thiazole dyes, xanthene dyes and cyanine dyes.

The pigments and dyes described above can be used in combination as the coloring material of the present invention.

The dispersion medium that can be used in the present invention is a non-polar insulating solvent, such as an aliphatic hydrocarbon solvent, specifically, Isopar of Exxon, Soltor of Philips Oil, and IP of Idemitsu Petrochemical. For solvent and petroleum naphtha, Shell Petrochemical Co., Ltd. B. R. , Sherzol and Pegazol from Mobil Oil. The required properties are low toxicity, low flammability and low odor.

When dispersing the colored resin particles in the dispersion medium in the present invention, a dispersant can be used if necessary. Dispersants that can be used include nonionic, cationic and anionic surfactants. For example, as nonionic activators, sorbitan fatty acid esters (sorbitan monooleate, sorbitan monolaurate, sorbitan sesquioleate, sorbitan trioleate, etc.), polyoxyethylene sorbitan fatty acid esters (polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan) Monooleate, etc.), polyethylene glycol fatty acid ester (polyoxyethylene monostearate, polyethylene glycol diisostearate, etc.), polyoxyethylene alkyl phenyl ether (polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, etc.) It is.
As the cationic activator, octadecylamine acetate,
Alkyl (hardened tallow) trimethylammonium chloride, polyoxyethylene octadecylamine and the like.
Examples of the anionic activator include sodium dodecylbenzenesulfonate, sodium alkyl (tallow) methyltaurate, sodium oleylmethyltaurate, sodium dioctylsulfosuccinate, and high molecular anions (polycarboxylic acid type). The characteristics required for the dispersant may be any as long as it is compatible with the nonpolar insulating solvent and can stably disperse the fine particles.

The ink viscosity as a physical property required for an ink for an ink-jet printer is defined as the stability of ink droplet formation under a high-speed response of a head when the temperature during operation of a printing apparatus is set at 0 to 50 ° C. From the viewpoint of flight stability, 30 mPa ·
s or less, and more preferably 1.0 to 15 mPa · s for realizing high-speed response.

Hereinafter, the components of the ink will be specifically described.

Table 1 shows the ink compositions of the examples according to the present invention and the ink compositions of the comparative examples (aqueous inks).

[0022]

[Table 1]

The ink compositions of Comparative Examples shown in Table 1 are almost the same as those of commercially available aqueous inks.

After the inks having the compositions shown in Table 1 were prepared, the following evaluation items were provided, and the inks for ink jet printers of the present invention and the inks of Comparative Examples were evaluated.

Print quality: After printing on various types of transfer paper,
The presence or absence of bleeding of the ink is evaluated by visual observation or microscopic observation (× 60). No bleeding can be confirmed by visual or microscopic observation. ... preferred (◎) ・ Bleeding cannot be confirmed visually, but can be confirmed by microscopic observation. ... Appropriate (O)-Bleeding can be confirmed both visually and with a microscope. ··· Classification and evaluation based on inappropriate (x). Table 2 shows the results.

Print drying property: After full solid printing, the time until ink transfer is eliminated by matching another recording paper to the print surface is investigated. Ink transfer is stopped within 5 seconds. ... preferred (◎) ・ Ink is not transferred within 60 seconds. ... Appropriate (O) ・ It takes 60 seconds or more until ink transfer stops. ...
Classification and evaluation were made according to inappropriate (x). Table 2 shows the results.

Ink clogging: A commercially available ink jet printer head is filled with ink, left for one week in a 40 ° C. environment without a cap on a nozzle, and the ink discharge state is evaluated. Suitable (◎) ・ Discharge by rubbing with a rubber plate ... Suitable (○) ・ No discharge. ··· Classification and evaluation based on inappropriate (x). Table 2 shows the results.

Oversight: After the solid printing, the printed matter is completely dried, and the printed portion is rubbed with a finger. ... preferred (◎) ・ Stain on the ground can be visually confirmed. ··· Classification and evaluation based on inappropriate (x). Table 2 shows the results.

[0029]

[Table 2]

The ink for an ink jet printer of the present invention has high print quality without bleeding in the evaluations performed this time, has a fast drying speed on recording paper, and has good results in a clogging test at the nozzle portion of the ink. The results also showed excellent results in the scratch resistance test, and were favorable as inks for inkjet printers. On the other hand, with the ink of the comparative example, although clogging was unlikely to occur, print quality, print dryness, and abrasion resistance were unsuitable as inks for inkjet printers.

Although the embodiments of the present invention have been described in detail, the ink for an ink jet printer of the present invention is not limited to these configurations, materials, and manufacturing methods.

[0032]

As described above, according to the ink for an ink jet printer of the present invention, there is no bleeding on plain paper which has been a problem in the past, excellent print drying properties, no clogging of nozzles, and abrasion resistance. It has an excellent effect.

Further, according to the ink for an ink jet printer of the present invention, high printing quality, high density, excellent ink drying property on recording paper, clogging resistance, and abrasion resistance are excellent. Multiple color,
(Full color) and high-speed page printers using line heads.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C09D 11/00-11/20 C09B 69/10 C09C 3/10

Claims (1)

(57) [Claims] 1. An ink for an ink jet printer, wherein resin particles colored by a pigment are dispersed in a dispersion medium which is a non-polar solvent.