JPH07133455A - Ink jet printer - Google Patents

Abstract

PURPOSE:To provide a printer for computers having highly excellent figure concentration without spreading and using an ink colored with a dyestuff or a pigment and consisting of specific polyester particles as a dispersoid. CONSTITUTION:This ink jet printer uses an ink which is a water dispersion, colored with a dyestuff or a pigment and contains polyester particles having 20-5000eq/ton ionic group (preferably containing a mono- or dicarboxylic acid, etc., having sulfonic acid alkali metal base or sulfonic acid ammonium base), jets ink drops from a nozzle unit of an ink jet head and prints on recording paper Here, the above mentioned polyester particles are preferably in an emulsion state having <=1 micron particle diameter and consist of a polyester resin consisting of polybasic carboxylic acids and polyhydric alcohols.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image or character output device, and more particularly to a computer printer.

[0002]

2. Description of the Related Art In recent years, computers, word processors, facsimiles and other information devices have been widely used in companies, self-employed persons, households and the like, and accordingly, image and character output devices have come to be widely used. Like the development of computers, the development of output devices has been remarkable, and in recent years, many improvements and inventions have been made to meet various needs such as higher speed, higher definition, and quieter.

Conventionally, a dot matrix printer has been widely used as an output device, but recently, a non-impact type printer with low noise has been used. Typical examples are shown below. (A) Thermal transfer printer An ink ribbon, which is an extremely thin polyester film coated with a thin ink wax, is heated by a thermal head to melt the wax on the ink ribbon and transfer it to recording paper. (B) Thermal printer A thermal recording paper containing a leuco dye or the like is heated by a thermal head to develop a color of the leuco dye for recording.

(C) Sublimation type printer An ink ribbon in which a sublimable dye is thinly coated on an extremely thin film such as polyester is heated by a thermal head,
The dye on the ink ribbon is sublimated and attached to the recording paper. (D) Laser printer This is an application of an electrophotographic system, which forms a latent image on a photosensitive drum with a semiconductor laser, develops it with toner, and transfers and fixes it on recording paper. (E) Inkjet Printer An inkjet printer ejects ink from a printhead nozzle, and there are many inkjet printers such as a piezo system, a bubble jet system, and a solid inkjet system.

[0005]

The above-described non-impact printer has many problems as described below. In the methods (a) and (c), the printing sound is small and very beautiful characters can be obtained, but a large amount of the base film is consumed and the running cost is high. Even in the method (b), the printing sound is small and clear characters can be printed, but there are problems that a dedicated recording paper must be used and that multicolor printing cannot be performed. In the (d) method, page printing is possible,
Although it has the feature of being able to print quiet and extremely high-definition characters, there are problems that the device becomes large and the device is expensive. In the method (e), when the ink adheres to the recording paper in the piezo and bubble jets, ink bleeding occurs, and if high definition is required, a dedicated recording paper must be used. On the other hand, the solid ink jet can obtain a good image independent of the recording paper, but has a drawback that the ink chamber and the print head must be constantly heated.

[0006]

The present invention provides a quiet, high-definition ink jet printer capable of eliminating ink bleeding on a recording paper and obtaining an extremely good image density. is there. That is, the present invention is an inkjet printer that prints on recording paper by ejecting ink droplets from the nozzle portion of the inkjet head,
The ink used in the inkjet printer is colored with a dye or a pigment, and is 20 to 5000 eq / to.
The inkjet printer is characterized by being an aqueous dispersion containing polyester particles containing an ionic group in the range of n as a dispersoid.

The ink jet print head used in the present invention may have any structure as long as it can eject liquid ink. However, due to the relationship with the ink used in the present invention, the piezo type is more preferable than the thermal head type. Good. For the piezo-type print head, the continuous ejection electric field deflection type is preferably used when high speed is required, and the drop-on-demand type is preferably used when the device cost is desired to be reduced. In addition, an electrostatic suction type may be used depending on the case.
The ink nozzle diameter of the printer of the present invention may be any size as long as it can form ink droplets, but the diameter is preferably 300 μm or less, more preferably 15 μm or less.
It is preferably 0 μm or less, more preferably 70 μm or less. The printer of the present invention may be equipped with a cleaning unit for preventing nozzle clogging of ink nozzles, if necessary.
Further, the recording paper feeding mechanism is not particularly limited.

The ink jet printer according to the present invention comprises:
Since an aqueous dispersion containing polyester particles as the dispersoid is used as the ink, the ink ejected from the nozzle adheres to the recording paper, and then water seeps into the recording paper, but the polyester particles spread due to the fibrous nature of the recording paper. It is possible to print without blurring. The ink used in the printer of the present invention is prepared by dispersing polyester particles so as not to cause bleeding as described above, and the polyester resin is preferably the one shown below.

The polyester colored particles used in the present invention are preferably in an emulsion state, but more preferably have a particle size of 1 micron or less. Further, the polyester resin used for the polyester colored particles of the present invention comprises polyvalent carboxylic acids and polyvalent alcohols. Examples of the polyvalent carboxylic acids used for the polyester resin include terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, diphenic acid, sulfoterephthalic acid and 5- Sulfoisophthalic acid, 4-sulfophthalic acid, 4
-Sulfonaphthalene-2,7 dicarboxylic acid, 5 [4-sulfophenoxy] isophthalic acid, sulfoterephthalic acid,
And / or an aromatic dicarboxylic acid such as a metal salt or ammonium salt thereof, an aromatic oxycarboxylic acid such as p-oxybenzoic acid p- (hydroxyethoxy) benzoic acid,
Aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, fumaric acid, maleic acid, itaconic acid, hexahydrophthalic acid,
Unsaturated aliphatic and alicyclic dicarboxylic acids such as tetrahydrophthalic acid, and other polyvalent carboxylic acids such as trimellitic acid, trimesic acid, and pyromellitic acid. Etc. can be illustrated.

Examples of the polyvalent alcohols used in the polyester resin include aliphatic polyvalent alcohols, alicyclic polyvalent alcohols, aromatic polyvalent alcohols and the like.
Examples of the aliphatic polyhydric alcohols include ethylene glycol
, Propylene glycol, 1,3-propanedioe
2,3-butanediol, 1,4-butanediol
1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol
, Dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, polyethylene glycol
Examples include aliphatic diols such as propylene, polypropylene glycol and polytetramethylene glycol, triols such as trimethylolethane, trimethylolpropane, glycerin, pentaerythritol and tetraols. it can.

The alicyclic polyvalent alcohols are 1,4-
Cyclohexanediol, 1,4-cyclohexanedimethanol, spiroglycol, hydrogenated bisphenol A, ethylene oxide adduct and propylene oxide adduct of hydrogenated bisphenol A, tricyclodecanediol, Examples thereof include tricyclodecane dimethanol. As aromatic polyhydric alcohols, paraxylene glycol, metaxylene glycol, orthoxylene glycol, 1,4-phenylene glycol, and ethylene oxide adduct of 1,4-phenylene glycol. , Bisphenol A, ethylene oxide adduct of bisphenol A, propylene oxide adduct and the like.

Further, as polyester polyol, ε
Examples thereof include lactone-based polyester polyols obtained by ring-opening polymerization of lactones such as caprolactone. In addition to these, a monofunctional monomer may be introduced into the polyester for the purpose of blocking polar groups at the ends of the polyester polymer. Examples of monofunctional monomers include benzoic acid, chlorobenzoic acid, bromobenzoic acid, parahydroxybenzoic acid, sulfobenzoic acid monoammonium salt, sulfobenzoic acid monosodium salt, cyclohexylaminocarbonylbenzoic acid, n-dodecylaminocarbonylbenzoic acid. Acid, tert-butylbenzoic acid, naphthalenecarboxylic acid, 4-methylbenzoic acid, 3-methylbenzoic acid, salicylic acid, thiosalicylic acid, phenylacetic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, octanecarboxylic acid, lauric acid, stearyl acid , And monocarboxylic acids such as lower alkyl esters thereof, or aliphatic alcohols
Mono alcohols such as alcohol, aromatic alcohol and alicyclic alcohol can be used.

In the present invention, the unsaturated monomer among these is an essential component, and the other components are appropriately selected depending on the glass transition temperature of the polyester resin, compatibility with the monomer and the like.

As the ionic group introduced into the polyester, a mono- or dicarboxylic acid having an alkali metal sulfonate or ammonium sulfonate can be preferably used. For example, an alkali metal carboxylate or ammonium carboxylate can be used. Having a monomer, a sulfuric acid group, a phosphoric acid group, a phosphonic acid group, a phosphinic acid group or an anionic group such as an ammonium salt or a metal salt thereof, or a cationic group such as a primary to tertiary amine group. You can use a quantity etc.

When an alkali metal carboxylate or ammonium carboxylate is introduced, a polyvalent carboxylic acid such as trimellitic acid is introduced into the system at the final stage of polymerization of polyester to add a carboxyl group to the polymer terminal. Then, a method of exchanging it with a carboxylate group by neutralizing it with ammonia, sodium hydroxide or the like can be used. Further, by containing a mono- or dicarboxylic acid having an alkali metal sulfonate or ammonium sulfonate, these ionic groups can be introduced into the polyester resin. As salts, ammonium-based ions, Li, Na,
Examples thereof include salts of K, Mg, Ca, Cu, Fe and the like, and particularly preferred are K salt or Na salt. In the present invention, 5-
It is preferable to use sodium sulfoisophthalic acid or metasodium sulfobenzoic acid. Alternatively, a carboxylate group and a sulfonate group may be used. It is essential that the average particle size of the fine particle dispersion used in the printer of the present invention is 1.0 μm or less, preferably 0.5 μm or less, more preferably 0.2 μm or less, and even more preferably 0.1 μm or less. Is. If the particle system of the fine particle dispersion exceeds this range, the dispersion stability may deteriorate.

[0016]

First Embodiment (Production of Printer) FIG. 1 is a schematic view of the configuration of a printer according to the present invention. The printer has a structure in which a print head having ink nozzles is scanned. When the print head reciprocates once, the paper feeding device serves as a mechanism for feeding the recording paper by one print head. FIG. 2 shows a block diagram of the head portion. The ink head is a piezo type on-demand type. As the orifice plate of the nozzle, a stainless steel plate having a thickness of 80 μm was used, and a hole was formed by etching to form a nozzle. Nozzle diameter is 80 μm
And

(Production of ink) In an autoclave equipped with a thermometer and a stirrer, 130 parts by weight of dimethyl terephthalate, 56 parts by weight of dimethyl isophthalate, 5 dimethyl ester of sulfoisophthalic acid 6 sodium 6 Parts by weight, ethylene glycol 159 parts by weight, tricyclodecane dimethanol 30 parts by weight, tetrabutoxy titanate 0.1 parts by weight were charged and the transesterification reaction was carried out by heating at 180 to 230 ° C. for 120 minutes. . Then, the reaction system was heated to 240 ° C., and the reaction was continued for 60 minutes at a system pressure of 1 to 10 mmHg, and as a result, a copolyester resin was obtained. Next, 340 parts by weight of the obtained polyester resin, 150 parts by weight of methyl ethyl ketone, 140 parts by weight of tetrahydrofuran, dye C.I. I. After dissolving 30 parts by weight of Disperse Blue 87 conc. And 4 parts by weight of 2,4-dihydroxobenzophenone at 80.degree. C., water 6 at 80.degree.
80 parts was added to obtain an aqueous microdispersion of a copolyester resin having a particle diameter of about 0.15 μm. Further, the obtained water-based microdispersion was placed in a distillation flask and distilled until the distillation temperature reached 100 ° C. After cooling, water was added to make the solid content concentration 30%. Hereinafter, the dyes: C.I. I. Disperse Yellow 198 C.I. I. Instead of Disperse Red 92, dyeing was performed in the same manner to obtain an aqueous microdispersion.

(Printing test) The ink produced as described above was put into the above-mentioned ink jet printer to perform a printing test. The paper used was unprocessed for inkjet. As a result, the printing of the printer of the present invention showed no ink bleeding. The density of the obtained image was extremely high and the image was clear.

[0019]

INDUSTRIAL APPLICABILITY The ink jet printer using the specific ink of the present invention can obtain a print result with high density of an image without ink bleeding.

[Brief description of drawings]

FIG. 1 shows a schematic configuration diagram of a printer of the present invention.

FIG. 2 is a schematic diagram showing the configuration of the head portion of the printer of the present invention.

[Explanation of symbols]

 1: Ink chamber 2: Vibration plate 3: Piezo element 4: Orifice plate 5: Ink

Claims (1)

[Claims] 1. An ink jet printer which prints on a recording paper by ejecting ink droplets from a nozzle of an ink jet head, wherein the ink used in the ink jet printer is colored with a dye or a pigment.
An ink jet printer characterized by being an aqueous dispersion comprising polyester particles containing an ionic group in the range of 5000 eq / ton as a dispersoid.