JP2000290563A - Diluting liquid for ink, and ink jet recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To print out an image and the like high in quality and good in water resistance by employing a diluting liquid having added thereto a water-soluble diallyldimethylammonium chloride polymer having a specific structure. SOLUTION: The title diluting liquid is obtained by adding 0.5-20 wt.% of a water-soluble polymer, represented by the formula whose nitrogen atom forms a quaternary ammonium salt in water, such as a diallyldimethylammonium chloride polymer PAS-H or the like to water or a mixture thereof with a water- soluble solvent. An ink is obtained by adding a water-soluble anionic dye such as a direct dye, an acid dye or the like or a cationic dye, a surfactant, an anti-foaming agent, a pH adjusting agent and the like to water having added thereto a solvent such as a monohydric alcohol, a polyhydric alcohol or the like. In an ink jet printer, the ink or the diluting liquid is allowed to ooze out from a second nozzle on a constant quantity side to a first nozzle on an ejection side and to mix with the diluting liquid or the ink in the first nozzle and the resulting diluted ink droplet is flied from the first nozzle onto a recording paper or the like to record an image or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink diluent and an ink jet recording method, and more particularly, to a dilute ink by mixing an ink and a diluent at a predetermined mixing ratio.
The present invention relates to an ink diluent and an ink jet recording method suitable for use in an ink jet recording apparatus in which the diluted ink droplet is ejected from a nozzle to fly on a recording medium.

[0002]

2. Description of the Related Art On-demand type ink jet printers have been put into practical use as small and inexpensive printers capable of dramatically improving the resolution and image quality of recorded images and the like. On-demand type inkjet printers discharge ink droplets from nozzles of a head device according to a control signal,
This is made to fly on a recording medium such as paper or film to record an image or the like. An on-demand type ink jet printer uses a piezoelectric method in which ink is pressurized by displacement of a piezo element and a bubble jet that uses the pressure of bubbles generated by heating and evaporating ink in a nozzle by a heating element as a method of flying ink droplets. Method is adopted.

[0003] As for printers, in offices,
Creation of documents and the like using a computer called desktop publishing has become popular, and there is an increasing demand for printing not only characters and figures but also color natural images such as photographs with characters and figures. There is a great demand for printers for creating New Year's cards and greeting cards even in personal use. 2. Description of the Related Art In a printer, in order to print out a high-quality natural image, gradation expression by halftone display is important.
In the above-described recording methods based on the piezoelectric method and the bubble jet method, since the ink density cannot be changed in principle immediately before ejection, it is difficult to express the halftone density in dot units on the recording medium. It is.

[0004] In the on-demand type ink jet printer, various methods have been proposed so far to simulate the gradation expression of a recorded image. For example, as a first method, there has been proposed a method in which the voltage or pulse width applied to a piezo element or a heating element is modulated to control the size of a droplet to be ejected, and the diameter of a print dot is made variable to express gradation. I have. However, the first method has a limitation on the minimum droplet diameter because the ink is not ejected if the voltage or the pulse width is excessively reduced, and is not suitable particularly for low-density gradation expression.

[0005] As a second method, one pixel is composed of a plurality of matrices, for example, one pixel is composed of a 4.times.4 dot matrix with a constant dot diameter, and a gradation is obtained by a so-called dither method in a unit of this matrix. It is a way to express. The second method enables expression of 17 gradations. However, in the second method, when printing is performed at the same dot density as the first method described above, the resolution is reduced to 1 /
4 and there is a problem that the roughness is conspicuous and a natural image cannot be sufficiently expressed. In the second method, when image processing is performed precisely in order to solve such a problem, the control circuit and the like become complicated and the arithmetic processing speed is reduced, that is, the printout time is lengthened. Occurs.

The present applicant has proposed a method for solving the above-mentioned problem of the conventional on-demand type printer in principle, which is disclosed in Japanese Patent Application Laid-Open No. Hei 5-201024, entitled "Inkjet Printer Head and Inkjet Printer". An inkjet printer head and an inkjet printer (hereinafter, referred to as a carrier jet type printer) are provided. A carrier jet type printer mixes ink and a diluent, which is a transparent medium, at a predetermined mixing ratio based on a control signal or the like immediately before ejection to form a diluted ink, and immediately ejects the diluted ink from a nozzle onto a recording medium. Print out images and so on by flying. Carrier jet printers express the gradation freely for each dot on a recording medium by controlling the density of each ink droplet ejected by mixing a diluent at a predetermined mixing ratio. Is possible. Therefore, the carrier jet type printer can print out a natural image rich in intermediate gradations with high accuracy without deteriorating the resolution.

[0007]

By the way, an ink jet printer uses an ink to which a dye generally called a direct dye or an acid dye is added. After being transferred to the dye receiving layer as represented by the dyeing theory, the direct dye is held in the receiving layer by interaction with the components of the dye receiving layer such as van der Waals force and hydrogen bonding. On the other hand, acidic dyes generally have the characteristics of low molecular weight and high water solubility.

As described above, the carrier jet type printer can print out a natural image rich in intermediate gradations with high accuracy, but water or the like is printed on a dedicated paper surface for printing out an image or the like depending on the characteristics of the ink used. When attached, there is a problem that the dye flows out and the durability is deteriorated. In addition, although the carrier jet type printer uses not only special paper but also generally used plain paper as a recording medium due to the above-described features, this plain paper also requires recording characteristics such as images equivalent to the special paper. ing.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink diluent and an ink jet recording method which can solve the above-mentioned problems of the conventional ink jet printer and can print out high quality and water resistant images. It is a proposal.

[0010]

The ink diluent according to the present invention, which achieves the above object, is added with a diallyldimethylammonium chloride polymer of a water-soluble polymer having the structural formula shown below.

[0011]

Embedded image

According to the ink diluent according to the present invention, the diallyldimethylammonium chloride polymer having the above-mentioned predetermined structural formula is added to water or a mixture of water and a solvent, whereby the ink is produced by an ink jet printer. When a predetermined amount is mixed and printed out, an image or the like having high image quality and water resistance can be printed out.

In the ink jet recording method according to the present invention, the ink or the diluting liquid is exuded from the second nozzle to the first nozzle side, and the ink and the diluting liquid are mixed in the first nozzle. In this state, the diluted ink droplet flies from the first nozzle onto the recording medium to record an image or the like. In the ink jet recording method, a diluent to which a diallyldimethylammonium chloride polymer of a water-soluble polymer having the structural formula shown below is used is used.

[0014]

Embedded image

According to the ink jet recording method of the present invention, a diluent obtained by adding a diallyl dimethyl ammonium chloride polymer having the above-mentioned predetermined structural formula to water or a mixture of water and a solvent is used. By printing out images, etc. by flying diluted ink droplets, which are a mixture of liquid and ink at a predetermined ratio, onto a recording medium, halftones can be reproduced with high precision, and high-quality images, etc. can be printed out. In addition, sufficient water resistance is maintained even when plain paper is used as a recording medium.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. First, a schematic configuration of an on-demand type inkjet printer 1 to which an inkjet recording method according to the present invention is applied will be described with reference to FIGS. The ink jet printer 1 includes an ink 2 described below in detail and a diluent 3
This is a so-called carrier-jet type printer in which a mixed ink liquid 4 having a predetermined concentration obtained by mixing these is ejected onto a recording material such as recording paper to print an image or the like.

The ink jet printer 1 will be described as a so-called piezoelectric ink jet printer that uses a pressure element such as a piezo element (not shown) to supply the ink 2 or the diluent 3 in a fixed amount. Of course, the ink jet printer 1 may be a bubble jet printer that supplies a fixed amount of the ink 2 or the diluent 3 by a so-called bubble jet method. In addition, the inkjet printer 1
May be configured such that the ink 2 serves as the ejection side and the diluent 3 serves as the quantitative side.

As shown in FIGS. 1 and 2, the ink jet printer 1 has a nozzle 6 on the ejection side (hereinafter, referred to as a diluent nozzle 6) and a nozzle 7 on the metering side (hereinafter, referred to as an ink nozzle 7). And orifice plates 5 independently provided. The orifice plate 5
It is formed from a metal plate such as nickel or stainless steel, a ceramic plate such as glass or silicon, or a plastic film such as polyimide or polyethylene terephthalate.

The orifice plate 5 is joined to the main surface of the head plate 8. In the head plate 8, a diluting liquid supply channel 9 communicating with the diluting nozzle 6 and an ink supply channel 10 communicating with the ink nozzle 7 are formed. Although not shown, an ink supply chamber and a diluent supply chamber are formed in the head plate 8, and a head drive mechanism including a piezo element and the like is additionally provided.

As the head driving mechanism, a laminated piezo element which extends in the longitudinal direction by applying a voltage is used as the piezo element. Of course, the head driving mechanism may use a laminated piezo element that contracts in the longitudinal direction by applying a voltage. As the inkjet printer 1, an inkjet printer using a piezo element for the fixed amount discharge of the ink 2 or the diluting liquid 3 has been described, but an inkjet printer using a heating element may be used. In addition, the inkjet printer 1 may employ an actuator such as an electromagnetic transducer or an electrostrictive element instead of the piezo element, and these elements may be housed in each supply chamber.

As shown in FIG. 1, the diluent nozzle 6 is formed as a straight through hole penetrating in the thickness direction of the orifice plate 5. Diluent nozzle 6
Has one opening serving as a discharge port 6a serving as a diluent orifice, and the other opening serving as a supply port 6b communicating with the diluent supply flow path 9. The diluent nozzle 6 is supplied with, for example, a diluent 3 of a transparent solvent from a diluent supply chamber through a diluent supply channel 7 to a supply port 6b. The diluting liquid nozzle 6 has a function of discharging liquid droplets, and the shape of the discharge port 6a is a point symmetrical shape. The discharge port 6a is formed in, for example, a circular shape or a square shape for ease of design and manufacture, but is formed in a circular shape in the embodiment.

The ink nozzle 7 is, for example, subjected to excimer laser processing so that the discharge port 7a serving as an ink orifice is changed to the discharge port 6 of the diluent nozzle 6 as shown in FIG.
It is formed as a through hole that is inclined so as to gradually approach toward “a”. The ink nozzle 7 has one opening serving as a discharge port 7 a serving as an ink orifice, and the other opening serving as a supply port 7 b communicating with the ink supply flow path 10. Ink is supplied to the ink nozzle 7 from an ink supply chamber through an ink supply passage 10 to a supply port 7b. The ink nozzle 7 has a discharge port 7a as shown in FIG.
Is opened in close proximity to the discharge port 6a of the diluting liquid nozzle 6, so that the quantitative mixing of the ink 2 and the diluting liquid 3 is easily performed.

The ink nozzle 7 has a circular discharge port 7a as shown in FIG. 2, but has a high degree of freedom in its shape. Therefore, the ink nozzle 7 is not limited to a circular shape, but may be, for example, an elliptical shape as shown in FIG. 3A, a triangular shape as shown in FIG. 3B, or a crescent shape as shown in FIG. You may. The ink nozzle 7 can be easily formed into an appropriate shape by changing the shape of the mask when performing laser processing on the orifice plate 5. As the circular ink nozzle 7, for example, a mask having an elliptical opening may be used.

In order to print out a color image, the ink jet printer 1 prepares the above-described printer devices corresponding to, for example, four colors of yellow, magenta, cyan, and black, and sets one of these printers (here, 4
One printer device forms one set. ) May be used as a head assembly, and a plurality of head assemblies may be arranged on a line to print out a recorded image.

In the ink jet printer 1, the head driving mechanism is driven based on the control signal, so that the mixed ink liquid 4 mixed at a predetermined density by the series of operations shown in FIG. To print out images. In the ink jet printer 1, as shown in FIG. 1A, the ink 2 is filled into the ink nozzle 7 from the ink supply channel 10 by the capillary pressure. In the ink jet printer 1, the diluent 3 is filled from the diluent supply channel 7 into the diluent nozzle 6 by capillary pressure.

In the ink jet printer 1, a predetermined initial voltage, for example, 10 V is applied to the piezo element in a standby state. In the inkjet printer 1, the initial voltage is reduced to 0 V based on the control signal, so that the piezo element is reduced, the diluent pressure chamber is brought into a negative pressure state, and the diluent 3 is drawn into the diluent nozzle 6. In the inkjet printer 1, a driving voltage is applied to the piezo element of the head driving mechanism corresponding to the ink pressure chamber to drive the diaphragm, so that a fixed amount of ink is supplied from the ink nozzle 7 as shown in FIG. 2 is extruded onto the main surface of the orifice plate 5. The ejection amount of the ink 2 is controlled by the voltage value or pulse width of the driving voltage pulse applied to the piezo element.

In the ink jet printer 1, a driving voltage, for example, 20 V is applied to the piezo element of the head driving mechanism corresponding to the diluting liquid pressure chamber to drive the diaphragm, as shown in FIG. The diluent 3 is discharged from the diluent nozzle 6. In the ink jet printer 1, the ink pressure chamber is in a negative pressure state with a predetermined amount of the ink 2 being pushed out, and the ink 2 is drawn into the ink nozzle 7 as shown in FIG. I have. In the ink jet printer 1, the diluent 3
As a result, the droplet of the mixed ink liquid 4 of the diluting liquid 3 and the ink 2 flies from the orifice plate 5 as shown in FIG.

Thereafter, in the ink jet printer 1, when the voltage applied to the piezo element is reduced to the initial voltage, the diluent pressure chamber becomes negative pressure, and the diluent 3
Is drawn into the diluent nozzle 6. In the ink jet printer 1, when the internal pressures of the ink pressure chamber and the diluent pressure chamber are in the initial state, the state returns to the initial state shown in FIG.

The above-described series of operations of the ink jet printer 1 is an example, and the present invention is not limited to this. The operation of the ink jet printer 1 is based on the timing and state, for example, the shape of the mixed ink liquid 4, the filling operation, etc., and the structural elements of the orifice plate 5 such as the opening diameters of the nozzles 6, 7 and the supply ports 6b, 7b. And the physical factors such as the viscosity and surface tension of the diluent 3 and the operating conditions such as the discharge frequency. Further, in the ink jet printer 1, the shape of each pressure chamber formed in the orifice plate 5 and the head plate 8 can be changed.

In the ink jet printer 1, the amount and time of the increase in the pressure of the ink 2, that is, the voltage value or the pulse width of the voltage pulse applied to the piezo element is adjusted, so that the dilution liquid 3 contained in the mixed ink liquid 4 is adjusted. The mixing ratio, that is, the ink density is adjusted. The ink-jet printer 1 can change the density for each dot, and by forming a large number of these dots, it is possible to express halftone gradations, and to print out a natural image with high-precision gradation expression. Is done.

The above-described ink jet printer 1 includes:
The ink 2 adjusted as follows is used. The ink 2 uses a water-soluble anionic dye (a water-soluble direct dye and a water-soluble acid dye) or a water-soluble cationic dye as a dye. The ink 2 is composed of the dyeing dye, water, and a water-soluble organic solvent.

The water-soluble anionic dye has, as a chromophore, a monoazo group, a disazo group, an anthraquinone skeleton, a triphenylmethane skeleton and the like, and further has one to three sulfonic acid groups or carboxyl groups in the molecule. Those having an ionic water-soluble group are used.

The water-soluble anionic dye is specifically, as a yellow direct dye, C.I. I. Direct Yellow 1, Same 8, Same 11, Same 12, Same 24, Same 26, Same 27,
28, 33, 39, 44, 50, 58, 85, 86, 88, 89, 98, 100, 110, etc. are used.

Specific examples of the water-soluble anionic dye include C.I. I. Direct Red 1,
2, 4, 9, 11, 13, 13, 17, 20,
23, 24, 28, 31, 33, 37, 39, 44, 46, 62, 63, 75, 7
9, 80, 81, 83, 84, 89, 9
5, 99, 113, 197, 201, 21
8, 220, 224, 225, 226, 22
7, 228, 229, 230, 321 and the like are used.

The water-soluble anionic dyes are specifically exemplified by C.I. I. Direct Blue 1, 2, 6, 8, 15, 15, 22, 25, 41, 71, 76, 77, 78, 80, 86, 9
0, 98, 106, 108, 120, 15
8, 160, 163, 165, 168, 19
2, 193, 194, 195, 196, 19
9, 200, 201, 202, 203, 20
7, 225, 226, 236, 237, 24
6, 248 and 249 are used.

The water-soluble anionic dye is, specifically, a plaque-based direct dye as C.I. I. Direct Black 1
7, 19, 22, 22, 32, 51, 5
6, 62, 71, 74, 75, 77, 9
4, 105, 106, 107, 108, 11
2, 113, 117, 118, 132, 1
33 and 146 are used.

Specific examples of the water-soluble anionic dye include C.I. I. Acid Yellow 1,
3, 7, 11, 17, 17, 19, 23, 2
5, 29, 36, 38, 40, 42, 4
4, same 49, same 59, same 61, same 70, same 72, same 7
5, 76, 78, 79, 98, 99, 11
0, 111, 112, 114, 116, 11
8, 119, 127, 128, 131, 13
5, same 141, same 142, same 161, same 162, same 16
3, 164 and 165 are used.

The water-soluble anionic dye is specifically exemplified by C.I. I. Acid Red 1, 6, 8, 9, 13, 14, 18, 18, 26, 27, 32, 35, 37, 42, 51, 5
2, 57, 75, 77, 80, 82, 8
3, 85, 87, 88, 89, 92, 9
4, 97, 106, 111, 114, 11
5, 117, 118, 119, 129, 13
0, 131, 133, 134, 138, 14
3, 145, 154, 155, 158, 16
8, 180, 183, 184, 186, 19
4, 198, 199, 209, 211, 21
5, 216, 217, 219, 249, 25
2, 254, 256, 257, 262, 26
5, 266, 274, 276, 282, 28
3, 303, 317, 318, 320, 32
1, 322, etc. are used.

Specific examples of the water-soluble anionic dye include C.I. I. Acid Blue 1, 7, 9, 9, 15, 22, 23, 25, 27,
29, 40, 41, 43, 45, 54, 59, 60, 62, 72, 74, 78, 8
0, 82, 83, 90, 92, 93, 10
0, 102, 103, 104, 112, 11
3, 117, 120, 126, 127, 12
9, 130, 131, 138, 140, 14
2, 143, 151, 154, 158, 16
1, 166, 167, 168, 170, 17
1, 175, 182, 183, 184, 18
7, 192, 199, 203, 204, 20
5, 229, 234, and 236 are used.

The water-soluble anionic dye is specifically exemplified by C.I. I. Acid Black 1,
2, 7, 24, 26, 29, 31, 31 and 4
4, 48, 50, 51, 52, 58, 6
0, 62, 63, 64, 67, 72, 7
6, 77, 94, 107, 108, 109,
110, 112, 115, 118, 119
121, 122, 131, 132, 139,
140, 155, 156, 157, 158,
159 and 191 are used.

In the ink 2, an aliphatic monohydric alcohol, a polyhydric alcohol, or a polyhydric alcohol derivative is used as a water-soluble organic solvent. As the aliphatic monohydric alcohol, lower alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, s-butyl alcohol and t-butyl alcohol are used. In the ink 2, when a monohydric alcohol is used as a solvent, the surface tension is adjusted, and a droplet of a mixed ink liquid 4 mixed with a diluting liquid 3 described later is applied to a recording medium such as plain paper or special paper. This has high effects of improving the permeability, dot forming property, and drying property of a printed image, and is thus suitable. As the monohydric alcohol, it is particularly preferable to use ethyl alcohol, i-propyl alcohol, n-propyl alcohol and the like.

Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butylene glycol,
Alkyl glycols such as glycerol, polyalkylene glycols such as polyethylene glycol and polypropylene glycol, and thiodiglycol are used. On the other hand, examples of the polyhydric alcohol derivatives include lower alkyl ethers of the above-mentioned polyhydric alcohols such as ethylene glycol dimethyl ether, cellosolve and diethylene glycol monomethyl ether, and lower carboxylic acid esters of the above-mentioned polyhydric alcohols such as ethylene glycol diacetate. Are used.

On the other hand, these polyhydric alcohols and derivatives thereof have an effect of preventing clogging of the nozzles 6 and 7 of the ink jet printer 1 when used as a solvent of the diluting liquid 3 to be described later. 3 has the effect of lowering the freezing point and increasing its preservability.

When at least one of the above-mentioned water-soluble organic solvents and water are added to the ink 2, an alcohol amine such as monotriethanolamine, ditriethanolamine, dimethylformamide, dimethyl Amides such as ketone amides, ketones such as acetone and methyl ethyl ketone, or ethers such as dioxane can be appropriately used. Further, additives such as various surfactants, an antifoaming agent, a pH adjusting agent or a fungicide may be added to the ink 2 in the solvent.

The diluent 3 contains a diallyldimethylammonium chloride polymer of a water-soluble polymer having the following structural formula, for example, a diallyldimethylammonium chloride polymer PAS-H (trade name) manufactured by Nitto Boseki Co., Ltd.
Is used. The diallyldimethylammonium chloride polymer PAS-H is positively charged in an aqueous solution, and all the nitrogen atoms in the molecule are in a quaternary ammonium salt state. Therefore, the diallyldimethylammonium chloride polymer P
AS-H does not lose its charge even in an alkaline atmosphere, and has a property that a positive charge state is maintained over the entire pH range.

[0046]

Embedded image

The diallyldimethylammonium chloride polymer PAS-H is a white powder and is generally provided in the form of an aqueous solution. The diallyldimethylammonium chloride polymer PAS-H is very stable even in acidic or alkaline conditions and has almost no decrease in molecular weight. Since it contains no ester bond or amide bond, it is hydrolyzed by acid or alkali and loses cationicity. There is a characteristic that there is no. The diallyldimethylammonium chloride polymer PAS-H is diluted by being dissolved in water or ethanol, but has the property of being insoluble in general organic solvents.

The diluent 3 contains 0.5% by weight of the above diallyldimethylammonium chloride polymer PAS-H.
-20% by weight. Diluent 3 was diallyldimethylammonium chloride polymer PAS-H0.5
When the content is less than 10% by weight, the water resistance is deteriorated as described later, and the effect cannot be exhibited. Further, in the diluent 3, the addition amount of the diallyldimethylammonium chloride polymer PAS-H may be 20% by weight or more depending on printing conditions and the like. However, the diluent 3 contains 2 parts of diallyldimethylammonium chloride polymer PAS-H.
When the content is 0% by weight or more, storage stability and discharge stability are deteriorated, and a solid concentration is increased, so that a reaction in the vicinity of the diluent nozzle 6 is likely to occur, which causes clogging. Problems arise.

[0049]

EXAMPLES Inks 2-1 to 2-16 having different dyes were prepared under the following conditions.

The following dyes were used for the inks 2-1 to 2-16. Ink 2-1 C.I. I. Direct Yellow 50 Ink 2-2 C.I. I. Direct Yellow 87 Ink 2-3 C.I. I. Direct Red 83 Ink 2-4 C.I. I. Direct Red 227 Ink 2-5 C.I. I. Direct Blue 6 Ink 2-6 C.I. I. Direct Blue 86 Ink 2-7 C.I. I. Direct Black 38 Ink 2-8 C.I. I. Direct Black 154 Ink 2-9 C.I. I. Acid Yellow 23 Ink 2-10 C.I. I. Acid Yellow 42 Ink 2-11 C.I. I. Acid Red 27 Ink 2-12 C.I. I. Acid Red 52 Ink 2-13 C.I. I. Acid Blue 9 Ink 2-14 C.I. I. Acid Blue 15 Ink 2-15 C.I. I. Acid Black 24 Ink 2-16 C.I. I. Acid Black 94

Under the following conditions, Example Diluents 3-1 to 3-3 to which dialsyldimethylammonium chloride polymer product name PAS-H-1L was added were prepared.

Example Diluent 3-1 Composition PAS-H-1L Solid content 20% by weight Water 80% by weight Example Diluent 3-2 Composition PAS-H-1L Solid content 1% by weight Water 89% by weight Isopropyl alcohol 5 % By weight Ethylene glycol 5% by weight Example diluent 3-3 Composition PAS-H-1L Solid content 0.5% by weight Water 88.5% by weight Ethanol 5% by weight Diethylene glycol 5% by weight

The above-described inks 2-1 to 2-16
Example Diluent 3 in which diallyl dimethyl ammonium chloride polymer PAS-H-1L was added to each
-1 to Example Diluent 3-3 were quantitatively mixed, and the water resistance was evaluated under the following conditions. The water resistance was evaluated by preparing print samples using the above-described inkjet printer 1 in which each of the inks 2 and the example diluent 3 were quantitatively mixed, and before and after immersion of these print samples for 1 hour. The concentration was measured and evaluated. The print sample was prepared in a state where the pulse voltage and the pulse width applied to the head drive unit were adjusted so that the optical density (OD value) was 0.5 and 1.0 with respect to plain paper. Macbeth densitometer TR-
Using 924, the density change before and after the measurement was evaluated by the following density remaining rate (%). Residual density (%) = optical density after immersion / optical density before immersion × 100

The results of the above-mentioned water resistance evaluation are as shown in Table 1 below. Table 1 shows that each of the above-mentioned inks 2 is taken in the column and each of the diluents 3 in the example is taken in the horizontal row. When a residual ratio higher than 80% is obtained in these combinations, the mark “、” indicates that 80% to 60%. % When a value of% was obtained, 6
When a value of 0% to 0% is obtained, this is indicated by a mark with an X mark.

[0055]

[Table 1]

As is clear from the above evaluation of water resistance, by using the diluent 3 in each of the examples in which the above diallyldimethylammonium chloride polymer PAS-H-1L was added to water or a solvent, a sufficiently effective concentration was obtained. The survival rate has been maintained. Specifically, with respect to a print sample which was printed at an optical density of 1.0 using Example Diluent 3-3, the density residual ratio was a little lower than 80% to 60%, which is not a problem in practical use. However, the remaining concentration ratio was 80 for all the other print samples.
% Or more.

The superiority of the above-mentioned diluent 3 is sufficiently proved as compared with the results of the water resistance evaluation of the comparative diluent 20 described below. Each comparative example diluent 20 is prepared as follows.

Comparative Example Diluent 20-1 Composition water 100% by weight Comparative Example Diluent 20-2 Composition water 90% by weight Isopropyl alcohol 5% by weight Ethylene glycol 5% by weight Comparative example diluent 20-3 Composition water 89% by weight isopropyl Alcohol 6% by weight Ethylene glycol 5% by weight Comparative example diluent 20-4 Composition water 89% by weight Isopropyl alcohol 5% by weight Ethylene glycol 6% by weight Comparative example diluent 20-5 Composition water 90% by weight Ethanol 5% by weight Diethylene glycol 5% by weight % Comparative example diluent 20-6 Composition water 89.5% by weight Ethanol 5.5% by weight Diethylene glycol 5% by weight Comparative example diluent 20-7 Composition water 89.5% by weight Ethanol 5% by weight Diethylene glycol 5.5% by weight

Using each of the comparative diluents 20 described above, a print sample was prepared in a state where these were quantitatively mixed with the respective inks 2, and the water resistance was evaluated. Water resistance evaluation,
The procedure was performed under the same conditions as in the case of using the diluent 3 of Example, and the results are shown in Table 2 below.

[0060]

[Table 2]

As can be seen from Table 2, the print samples using each of the comparative diluents 20 had a residual concentration of 60% or less, and did not retain sufficient water resistance. Therefore, the diluent 3 contains the diallyl dimethyl ammonium chloride polymer PAS described above.
By adding -H-1L, when an image or the like is printed out by the inkjet printer 1, it is possible to print out an image or the like having high image quality and water resistance.

[0062]

As described above in detail, according to the ink diluent of the present invention, the water-soluble polymer diallyldimethylammonium chloride polymer is added to water or a mixture of water and a solvent. When a predetermined amount of ink is mixed with an ink by an ink-jet printer to print out an image or the like, it is possible to print out a high-quality image or the like in which halftones are reproduced with high precision, and to print on plain paper. Even when printing is performed, the water resistance is sufficiently maintained.

According to the ink jet recording method of the present invention, the ink or the diluting liquid is exuded from the second nozzle to the first nozzle side, and the mixing of the ink and the diluting liquid is performed at the first nozzle. In this state, the diluted ink droplets are ejected from a first nozzle onto a recording medium to record an image or the like, and the diluent is water or a mixture of water and a solvent, and a water-soluble polymer diallyldimethylammonium chloride is used. By using a diluent to which a polymer is added, even when printed on plain paper, it is possible to print out high-quality images with halftones reproduced with high precision, and with sufficient water resistance. Become.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part showing a configuration of a head unit of an on-demand type ink jet printer.

FIG. 2 is a plan view of a main part showing a configuration of a nozzle of the head unit.

FIG. 3 is a main part plan view showing a configuration of another nozzle of the head unit.

FIG. 4 is a diagram illustrating a printout operation of an image or the like by the inkjet printer.

[Explanation of symbols]

1. On-demand type inkjet printer (inkjet printer), 2 inks, 3 diluents, 4 mixed inks, 5 orifice plate, 6 diluent nozzle,
7 ink nozzle, 8 head plate, 9 diluent supply passage, 10 ink supply passage

Claims (5)

[Claims] A first nozzle for discharging a diluting liquid or ink and a second nozzle for discharging an ink or diluting liquid are provided, and the ink or diluting liquid is provided from the second nozzle to the first nozzle side. Is used in an ink jet recording apparatus for recording an image or the like by ejecting diluted ink droplets from the first nozzle onto a recording medium in a state where the ink and the diluent are mixed with each other. An ink diluent comprising a water-soluble polymer diallyldimethylammonium chloride polymer represented by the following structural formula: Embedded image A first nozzle for discharging the diluting liquid or the ink and a second nozzle for discharging the ink or the diluting liquid, wherein the ink or the diluting liquid is provided from the second nozzle to the first nozzle side. In the ink jet recording method of recording an image or the like by ejecting diluted ink droplets from the first nozzle onto a recording medium in a state where the ink and the diluent are mixed with each other, An ink-jet recording method comprising using a diluent to which a diallyldimethylammonium chloride polymer of a water-soluble polymer represented by the following chemical formula 2 is added. Embedded image 3. The ink jet recording method according to claim 2, wherein a diluent to which water and a water-soluble solvent are added is used as the diluting liquid. 4. The ink jet recording method according to claim 2, wherein an ink to which a dye is directly added is used as the ink. 5. The ink jet recording method according to claim 2, wherein an ink to which an acidic pigment is added is used as the ink.