JPH09124982A - Diluting liquid for ink jet recording ink, ink for ink jet recording, and ink jet recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a diluting liq. for ink jet recording which can maintain wetting and moisture retention of an ink in the vicinity of a nozzle to prevent clogging of the nozzle, can improve the fixation of the ink onto a recording medium and realizes highly stable and reliable ink jet recording by mixing a diluting liq. contg. isoprene glycol with an ink. SOLUTION: An ink contained in an ink vessel 2 is filled into an ink reservoir 22, an ink feed port 111, and an ink flow passage 121 and creates a meniscus Mi at the front end of the ink flow passage 121. A diluting liq., contg. 1 to 50wt.% isoprene glycol, contained in a vessel 3 is filled into a diluting liq. reservoir 32 and a diluting liq. feed port 112 and creates a meniscus Md. An ink drive section 23 is actuated to create an ink droplet in the front end of the meniscus Mi in the diluting liq. feed port 112, and the ink droplet is immediately mixed with the diluting liq. to form a diluted ink. A diluting liq. drive section 33 is actuated to move the diluted ink formed at the diluting liq. feed port 112 toward a nozzle 113 and ejects the diluted ink through the nozzle. The ejected diluted ink is deposited as a spherically ejected ink 6 onto a recording medium.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording ink diluent, an ink jet recording ink and an ink jet recording method, and more specifically, an ink jet recording ink diluent excellent in moisture retention and dryness.
The present invention relates to an inkjet recording ink and an inkjet recording method.

[0002]

2. Description of the Related Art An on-demand type ink jet recording printer is a printer that ejects ink droplets from a nozzle in accordance with a control signal and deposits the droplets on a recording medium such as paper or film. It has become popular rapidly in recent years due to the possibility of cost reduction. The method of ejecting ink droplets from the nozzle is roughly classified into a method in which the ink is pressurized by the displacement of the piezo element, and a method in which the ink in the nozzle is heated and vaporized by the heating element and the pressure of the generated bubbles is used. You. In principle, none of the methods can change the ink density immediately before the ejection, and therefore, it is not possible to express halftone density gradation in dot units on the recording medium.

On the other hand, in the office, document creation by 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 together with characters and figures. Even for personal use, such demand is great for New Year's cards and greeting cards. In order to print out a high-quality natural image, it is important to express gradation by displaying halftones.

Conventionally, the following methods have been proposed as a method of pseudo gradation expression in an on-demand type ink jet recording method. The first method is to modulate the voltage applied to the piezo element or the heating element or the pulse width to control the size of the ejected droplet, and to change the diameter of the print dot to express the gradation. The second method is a method of expressing gradation by image processing such as a dither method or an error diffusion method while keeping the print dot diameter constant. In addition to this, there are cases where image processing techniques such as contour enhancement processing and smoothing processing are combined.

However, in the first method, if the voltage or pulse width is lowered too much, the ink cannot be ejected, and therefore the minimum droplet diameter is limited, and it is particularly unsuitable for low density gradation expression. In the second method, for example, when one pixel is composed of a 4 × 4 matrix, the resolution deteriorates to ¼ and the roughness is conspicuous, and if the image processing is strict, the circuit becomes complicated and the arithmetic processing is performed. This leads to a decrease in speed, that is, a longer printout time.

As a method for solving the above-mentioned problems of the conventional on-demand type ink jet recording in principle, the applicant of the present invention mixes ink and a diluent which is a transparent solvent at a predetermined mixing ratio immediately before jetting. An inkjet recording method (hereinafter referred to as a carrier jet method) in which a diluted ink is immediately ejected from a nozzle and adhered onto a recording medium has been developed and disclosed in Japanese Patent Laid-Open No. 5-201024. According to the carrier jet method, it is possible to control the ink density for each ejected ink droplet and freely express the gradation for each dot on the recording medium.
Therefore, it is possible to print out a natural image rich in halftones without deteriorating the resolution.

[0007]

The carrier jet system is a system in which the ink and the diluent are mixed at an arbitrary mixing ratio immediately before jetting, so that the material, composition ratio, physical properties, etc. of the ink and the diluent are mixed. The degree of freedom of choice will increase dramatically. Not only in the carrier jet method, but also in normal ink jet recording, in the vicinity of the nozzle of the printer head where the diluting liquid or the ink is in direct contact with the air, the diluting liquid or the ink is always kept in an appropriate wet state. It is important for preventing clogging due to drying and preventing instability of ink ejection due to excessive wetting in the vicinity of the nozzle, and for stable printing or image formation. On the other hand, the ink or diluted ink attached to the recording medium has a quick drying property, and does not cause the inconvenience of being attached to the hand or soiling the printed matter when the print or image is rubbed with the hand or paper. Characteristics are also important.

The present invention can prevent clogging of the printer head and instability of jetting, and prevent contamination of the printed matter in any of the carrier jet method and the ordinary one-liquid type ink jet recording method. It is an object of the present invention to provide a diluent for an inkjet recording ink, an inkjet recording ink, and an inkjet recording method using the same, which have an excellent balance between properties, moisture retention and dryness.

[0009]

DISCLOSURE OF THE INVENTION The diluent for ink jet recording ink of the present invention is proposed in order to solve the above-mentioned problems, and the ink and the diluent are mixed at a predetermined mixing ratio immediately before jetting. A diluting ink is a diluting ink, and the diluting ink is ejected from a nozzle to be attached onto a recording medium, and the diluting liquid contains at least isoprene glycol. The content of isoprene glycol is preferably 1% by weight or more and 50% by weight or less with respect to the diluent.
It is more desirable that the content is not less than 30% by weight.
If it is less than 1% by weight, the effect of wettability and moisture retention cannot be obtained, and 5
When it exceeds 0% by weight, the drying property on the recording medium is deteriorated.
The diluting liquid of the present invention contains isoprene glycol as an essential component, but it is desirable to contain water or an aliphatic monohydric alcohol in addition to it, and may also contain an aliphatic polyhydric alcohol or its derivative, or other additives.

As the aliphatic monohydric alcohol, methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol,
Lower alcohols such as s-butyl alcohol and t-butyl alcohol are exemplified. Among these monohydric alcohols, ethyl alcohol, i-propyl alcohol and n-butyl alcohol can be preferably used. Such a monohydric alcohol improves the penetrability of a diluted ink diluted with a diluting liquid into a recording medium such as plain paper or special paper, the dot forming property, and the drying property of a printed image.

As the aliphatic polyhydric alcohol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butylene glycol,
Examples include alkylene glycols such as glycerol, polyalkylene glycols such as polyethylene glycol and polypropylene glycol, and thiodiglycol. Examples of the aliphatic polyhydric alcohol derivative include ethylene glycol dimethyl ether, cellosolve, diethylene glycol monomethyl ether and the like, lower alkyl ethers of the above polyhydric alcohols, lower carboxylic acid esters of the above polyhydric alcohols such as ethylene glycol diacetate and the like. To be done. These aliphatic polyhydric alcohols and their derivatives assist in preventing clogging of the nozzles of the printer, and when the diluting liquid contains water, lower the freezing point and improve the storage stability.

In addition to at least one of these compounds and water, alcohol amines such as mono-, di- and triethanolamine, amides such as dimethylformamide and dimethylacetamide, ketones such as acetone and methylethylketone, dioxane and the like. Ethers, various surfactants, antifoaming agents, pH adjusting agents, antifungal agents and the like may be optionally added.

Next, the ink jet recording ink of the present invention is characterized by containing at least isoprene glycol. The content of isoprene glycol is preferably 1% by weight or more and 50% by weight or less with respect to the ink for inkjet recording, and 3% by weight or more and 30% by weight or less.
The following is more desirable. If it is less than 1% by weight, the effect of wettability and moisture retention cannot be obtained, and if it exceeds 50% by weight, the drying property on the recording medium is deteriorated. The ink for inkjet recording of the present invention contains isoprene glycol and, of course, a dye or a pigment as essential components.
It is desirable to contain a polyhydric alcohol, and it may also contain an aliphatic polyhydric alcohol, its derivative, various additives and the like.

As the aliphatic monohydric alcohol, methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol,
Lower alcohols such as s-butyl alcohol and t-butyl alcohol are exemplified. Among these monohydric alcohols, ethyl alcohol, i-propyl alcohol and n-butyl alcohol can be preferably used. Such a monohydric alcohol improves the penetrability of a diluted ink diluted with a diluting liquid into a recording medium such as plain paper or special paper, the dot forming property, and the drying property of a printed image.

As the aliphatic polyhydric alcohol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butylene glycol,
Examples include alkylene glycols such as glycerol, polyalkylene glycols such as polyethylene glycol and polypropylene glycol, and thiodiglycol. Examples of the aliphatic polyhydric alcohol derivative include ethylene glycol dimethyl ether, cellosolve, diethylene glycol monomethyl ether and the like, lower alkyl ethers of the above polyhydric alcohols, lower carboxylic acid esters of the above polyhydric alcohols such as ethylene glycol diacetate and the like. To be done. These aliphatic polyhydric alcohols and their derivatives prevent clogging of the nozzles of the printer, and when the diluting liquid contains water, lower the freezing point and improve the storage stability.

In addition to at least one of these compounds and water, alcohol amines such as mono-, di- and triethanolamine, amides such as dimethylformamide and dimethylacetamide, ketones such as acetone and methylethylketone, dioxane and the like. Ethers, various surfactants, antifoaming agents, pH adjusting agents, antifungal agents and the like may be optionally added.

The isoprene glycol used in the ink jet recording diluent and ink jet recording ink of the present invention has a structure represented by the following chemical formula (1) and has a melting point of -50 ° C or lower and a boiling point of 203 ° C. , Soluble in water and alcohol. Also, since the toxicity is extremely low, there is no problem in using it in the office or home. The present inventors have found that by adopting the above-mentioned isoprene glycol having a specific structure, a diluent for inkjet recording and an inkjet recording ink having excellent wettability and moisture retention can be obtained.

[0018]

Embedded image

Further, the ink jet recording method of the present invention is characterized in that ink jet recording is carried out by a carrier jet method using the above-mentioned diluent for ink jet recording ink having a specific composition.

Furthermore, the ink jet recording method of the present invention is characterized in that the ink jet recording ink having the above-mentioned specific composition is used to perform ordinary one-component ink jet recording.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described. First, the structure of the printer head, which is the main part of the carrier jet type printing apparatus used in this embodiment, will be described with reference to FIGS.

FIG. 1 is a schematic sectional view of a main part of a carrier jet type printer head. This printer head is
The orifice plate 1, the ink container 2, and the diluting liquid container 3 are roughly configured. First, the orifice plate 1 includes a first plate 11 and a second plate 12.
And the 3rd plate 13 is laminated | stacked and comprised in this order.

The first plate 11 has an ink supply port 1
11 and the diluent supply port 112 are opened. Third
A nozzle 131 for ejecting diluted ink obtained by mixing the ink and the diluent supplied from the ink supply port 111 and the diluent supply port 112 is opened in the plate 13 at a position facing the diluent supply port 112. ing. The nozzle 131 may be formed at a position facing the ink supply port 111. The second plate 12 is sandwiched between the first plate 11 and the third plate 13, is made of a dry film resist or the like, and the ink flow path 121 is formed. The ink flow path 121 is connected to the ink supply port 111 and the diluting liquid supply port 112, and is also connected to the nozzle 131.

FIG. 2 is a schematic plan view of the orifice plate 1 of the above-described carrier jet type printer head, as seen from the third plate 13 side. As shown in the figure, the planar shapes of the ink supply port 111 and the diluting liquid supply port 112 are formed as circular through holes in the first plate, but they are not necessarily circular and may be elliptical, square, rectangular, or the like. The shape may be.

The nozzle 131 is provided on the third plate at a position facing the diluent supply port 112, and the diluent supply port 112 is provided on the third plate.
It is formed as a circular through hole having a larger opening diameter. It is desirable that the nozzle 131 has an opening diameter larger than that of the diluting liquid supply port 112, but it may have the same diameter as or smaller than the diluting liquid supply port 112, and its planar shape does not need to be circular, and may be elliptical. The shape may be a square, a rectangle, or the like.

The ink flow path 121 has an ink supply port 111.
It is formed in a tapered shape in which the width gradually narrows toward the nozzle 131. However, the ink flow paths 121 may have the same width without being particular about this shape, or may have an inverse taper shape that widens. The tip of the ink flow path 121 is expanded into a shape substantially the same as the nozzle 131,
It forms a part of the nozzle 131.

Next, the ink container 2 and the diluent container 3 connected to the orifice plate 1 will be described again with reference to FIG. The ink container 2 and the diluent container 3 are
Since the structures are almost the same, they will be described collectively. The ink inlet 21 and the diluent inlet 31 are connected to the hollow ink reservoir 22 and the diluent reservoir 32. The other ends of the ink pool 22 and the diluent pool 32 are connected to the first plate 11 of the orifice plate 1.
Are connected to the ink supply port 111 and the diluting liquid supply port 112, respectively. Ink container 2 and diluent container 3
On the outer wall surface of the ink reservoir 22 and the diluent reservoir 3
2, the ink drive unit 23 and the diluting liquid drive unit 3
3 are provided. The ink driving unit 23 and the diluting liquid driving unit 33 are formed of bimorph piezoelectric elements, but other driving means, for example, actuators such as electromagnetic conversion elements or electrostrictive elements may be used. Further, the ink driving unit 23 and the diluting liquid driving unit 33 may be incorporated in the wall surfaces of the ink container 2 and the diluting liquid container 3.

Next, the operation of the above-mentioned carrier jet type printer head will be described with reference to the schematic sectional operation diagrams for explaining the operation of the carrier jet type printer head shown in FIGS. 3 to 7
1 are the same as those shown in FIG. 1 and are designated by common reference numerals.

The ink and the diluent, which are transported from an ink cartridge and a diluent cartridge (not shown) via a tube or the like, are introduced into the ink container 2 and the diluent container 3 from the ink inlet 21 and the diluent inlet 31. , The ink reservoir 22 and the diluent reservoir 32 are filled.

The ink filled in the ink reservoir 22 is
Further, the ink flow passage 121 is filled from the ink supply port 111, and a meniscus M _i is formed at the tip of the ink flow passage 121 facing the nozzle 131 by a capillary phenomenon.

On the other hand, the diluting liquid filled in the diluting liquid reservoir 32 further fills the diluting liquid supply port 112, and a meniscus M _d is formed there by the capillary phenomenon. This state is shown in FIG.

When printing is performed from this state, first, a pulse voltage is supplied to the ink drive unit 23 to supply ink to the ink container 2.
The inner pressure of the ink reservoir 22 is increased by applying a stress to the wall surface of the ink. As a result, the ink in the ink flow path 121 moves in the direction of its tip, and the tip of the meniscus M _i is at the dilution liquid supply port 1
12 is reached and an ink drop 4 is formed there. The volume of the ink droplet 4 is controlled by the pulse voltage applied to the ink driving unit 23, the pulse width, the number of pulses, and the like. This state is shown in FIG.

When the pulse voltage applied to the ink drive section 23 is released, the meniscus M _i retreats to the tip of the ink flow path 121, and the ink droplet 4 is left in the diluent supply port 112. This state is shown in FIG. The ink droplets 4 are shown for the purpose of explaining the transitional state, and the time when the ink droplets 4 independently exist is extremely short. That is, the ink droplet 4 immediately mixes with the diluting liquid exposed as the meniscus M _d in the diluting liquid supply port 112, and becomes the diluting ink 5. This state is shown in FIG.
The mixing ratio of the ink in the diluted ink 5, that is, the ratio of the ink and the diluent, can be controlled by the volume of the ink droplet 4, that is, the pulse voltage or pulse width applied to the ink drive unit 23, the number of pulses, and the like. Therefore, a diluting liquid ink capable of expressing halftone density is prepared at this stage.

Next, when a pulse voltage is applied to the diluting liquid drive unit 33 of the diluting liquid container 3, the internal pressure of the diluting liquid reservoir 132 rises, and the diluting ink 5 formed in the diluting liquid supply port 112 moves toward the nozzle 131. And is ejected from the nozzle 131. The ejected diluent ink 5 becomes a spherical ejected ink 6 due to the surface tension, and adheres to a recording medium such as unillustrated special paper or plain paper. Meanwhile diluted ink 5
The meniscus M _d made of a new dilution liquid is formed again at the dilution liquid supply port 112 after the ejection of the liquid. The above is 1
This is a jetting operation of a cycle, and an image or the like is formed on a recording medium by sequentially repeating this cycle. In the case of a color image, yellow (hereinafter referred to as Y), magenta (hereinafter referred to as M), cyan (hereinafter referred to as C), black (B), and the like are associated with, for example, four printer heads. It goes without saying that a large number of these printer head assemblies are arranged in parallel on a line to form an image.

The above-described structure and operation of the carrier jet type printer head are examples, and the shapes of the orifice plate, the ink container and the diluent container can be variously changed. For example, it is also possible to open a nozzle 131 at a position facing the ink supply port 111, mix a diluting liquid with the ink to form a diluting ink, and eject the diluting ink. Further, various changes can be made to the timing of various operations. According to the carrier jet type printer head, it is possible to express a halftone for each dot.
It is possible to print out a natural image with accurate gradation expression.

The above is the structure and operation of the main part of the carrier jet type printer head. However, for the printer head of an ordinary one-liquid type ink jet recording apparatus, it is known regardless of the piezo element driving method or the heating element driving method. The method of may be adopted.

Next, when various diluting liquids are prepared and various diluting liquids and ink are mixed by a carrier jet type printer head immediately before jetting to form an image, the wettability / moisture retaining property of the nozzle of the printer head and the recording medium The fixability of the above ink was evaluated. For ink, two sets of Y, M and C combinations (ink sample 1 and ink sample 2) for a commercially available inkjet recording device and one set of Y, M and C combinations (ink sample 3) using the following prototype inks are used. I was there. Ink sample 3 Dye 3% by weight Y: C.I. I. Acid Yellow 23 M: C.I. I. Acid Red 52 C: C.I. I. Acid Blue 9 Diethylene glycol 14% by weight Isopropyl alcohol 3% by weight Water 80% by weight

The composition of the diluting liquid in each example will be illustrated below. The composition is shown in% by weight.

Example 1 Water 90.0 Isoprene glycol 10.0

Example 2 Water 85.0 Isopropyl alcohol 5.0 Isoprene glycol 10.0

Example 3 Water 40.0 Ethyl alcohol 50.0 Diethylene glycol 3.0 Isoprene glycol 7.0

Example 4 Isopropyl alcohol 79.9 Isoprene glycol 20.0 Nonionic surfactant Emulgen 985 0.1 (manufactured by Kao Corporation)

Comparative Examples 1 to 4 The compositions of the diluents of Examples 1 to 4 excluding isoprene glycol.

An image of each color was formed by a carrier jet type printer head by using each color (Y, M and C) of each ink sample described above with the diluting liquid of each Example and Comparative Example, and the printer head was wetted. The properties, moisture retention and dryness on the recording medium were evaluated. Commercially available plain paper for inkjet recording was used as the recording medium.

As the method for evaluating the wettability / humidity retention, the vicinity of the nozzle of the printer head was visually inspected, and the nozzle was checked for clogging and the stability of ink ejection. Nozzle clogging occurs after printing or image formation is continuously performed for 10 minutes and then temporarily stopped, and after leaving for 10 minutes without capping the printer head, reprinting or image formation is performed without wiping the nozzle surface. , Inspected for the presence or absence of fading or missing characters or images. The inspection criteria were the following three levels. ○: No nozzle clogging was observed, and a stable ink ejection state was maintained. B: Nozzle clogging was occasionally observed, and irregularities in the ink ejection state were occasionally observed. ×: Nozzle clogging or irregular ink ejection state was observed. The evaluation results of wettability and moisture retention are summarized in [Table 1].

[0046]

[Table 1]

The results shown in Table 1 show that the diluent containing isoprene glycol has excellent wettability and moisture retention in the vicinity of the nozzle of the printer head, nozzle clogging does not occur, and stable carrier jet ink jet recording is possible. It shows that. On the other hand, in each of Comparative Examples 1 to 4 in which isoprene glycol was not contained in the diluting liquid, nozzle clogging occurred, and a stable ink ejection state could not be obtained.

Next, the method for evaluating the ink fixability on the recording medium is as follows: characters are printed as an image on the recording medium, the printed characters are rubbed on the same copy paper at regular intervals, and the ink tail is printed. The time required for the pulling to disappear and the copy paper to become clean was evaluated. That is, this time is short if the diluting ink has good drying properties and penetrating properties. ◯: less than 15 seconds Δ: 15 seconds or more and 30 seconds or less × ... more than 30 seconds Ink fixing property evaluation results are summarized in [Table 2].

[0049]

[Table 2]

From the results shown in Table 2, it can be seen that the diluent containing isoprene glycol is excellent in the fixing property of ink, that is, the drying property, and the copy paper is not stained due to the tailing of the ink. On the other hand, in Comparative Examples 1 to 4 in which isoprene glycol was not contained in the diluting liquid, the tailing of the ink was caused by the rubbing of the recording media.

When the evaluation results of [Table 1] and [Table 2] are summed up, when the carrier jet type ink diluting liquid contains at least isoprene glycol, excellent wettability and moisture retention near the nozzle of the printer head are obtained. It is clear that nozzle clogging does not occur and ink fixability is excellent, and stable and highly reliable inkjet recording is possible.

Next, regardless of the carrier jet method,
An example in which the present invention is applied to a normal one-component ink jet recording ink will be shown. A combination of Y, M, and C (trial ink 4) using the trial inks is illustrated below.

Example 5 Ink Sample 4 Dye 2.5 wt% Y: C.I. I. Acid Yellow 23 M: C.I. I. Acid Red 52 C: C.I. I. Acid Blue 9 Isoprene glycol 10% by weight Isopropyl alcohol 3.5% by weight Water 84% by weight

Comparative Example 5 Ink Sample 5 Dye 2.5 wt% Y: C.I. I. Acid Yellow 23 M: C.I. I. Acid Red 52 C: C.I. I. Acid Blue 9 Isopropyl alcohol 3.5% by weight Water 96% by weight Ink sample 5 is prepared by removing isoprene glycol from Ink 4 in Example 5 and adding diethylene glycol by that amount.

Regarding Example 5 and Comparative Example 5, the wettability
The results of moisturizing evaluation are shown in [Table 3]. The evaluation criteria are the same as those described above.

[0056]

[Table 3]

Further, in Example 5 and Comparative Example 5, the results of evaluation of the fixability of the ink on the recording medium are shown in Table 4. The evaluation criteria are the same as those described above.

[0058]

[Table 4]

When the evaluation results of [Table 3] and [Table 4] are summed up, even in the ordinary one-component ink jet recording other than the carrier jet method, when the ink contains at least isoprene glycol, It has excellent wettability and moisture retention near the nozzle, does not cause nozzle clogging, and has excellent ink fixability.
It is clear that stable and highly reliable inkjet recording becomes possible.

Although the present invention has been described in detail with reference to five examples, the compositions of the diluent and the ink are merely examples.
It can be appropriately modified within the scope of the technical idea of the present invention in which at least isoprene glycol is contained as an essential component.

[0061]

As is apparent from the above description, according to the ink jet recording ink diluent, the ink jet recording ink and the ink jet recording method of the present invention,
By adding isoprene glycol to the diluent in the carrier jet system and to the ink in the normal one-component ink jet recording other than the carrier jet system, the wettability of the ink near the nozzle can be improved.
It keeps moisture and prevents clogging. At the same time, the fixability of the ink on the recording medium is also improved, print printing and image stains due to rubbing and the like are avoided, and stable and reliable inkjet recording becomes possible.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a main part of a carrier jet type printer head.

FIG. 2 is a schematic plan view of an orifice plate of a carrier jet type printer head.

FIG. 3 is a schematic cross-sectional view for explaining the operation of a carrier jet type printer head, showing a state where meniscus M _i and meniscus M _d are formed by filling ink and a diluting liquid.

FIG. 4 is a schematic cross-sectional view for explaining the operation of a carrier jet type printer head, in a state where ink droplets are formed by driving an ink driving unit.

FIG. 5 is a schematic cross-sectional view for explaining the operation of the carrier jet type printer head, in a state where the drive of the ink drive unit is released and ink droplets are left at the diluent supply port.

FIG. 6 is a schematic cross-sectional view for explaining the operation of the carrier jet type printer head, showing a state in which diluted ink is formed in the diluted liquid supply port.

FIG. 7 is a schematic cross-sectional view for explaining the operation of a carrier jet type printer head, in a state in which a diluting liquid drive unit is driven to form ejected ink.

[Explanation of symbols]

1 Orifice Plate 111 Ink Supply Port 112 Diluent Supply Port 121 Ink Flow Path 131 Nozzle 2 Ink Container 21 Ink Inlet Port 22 Ink Pool 23 Ink Driving Section 3 Diluting Liquid Container 31 Diluting Liquid Inlet 32 Diluting Liquid Pool 33 Diluting Liquid Driving Section 4 Ink Drop 5 Diluent Ink 6 Jet Ink M _i Ink Meniscus M _d Diluent Meniscus

Claims (8)

[Claims] 1. A diluent for ink jet recording ink, which comprises mixing an ink and a diluent at a predetermined mixing ratio immediately before ejection to form a dilution ink, and ejecting the dilution ink from a nozzle to adhere onto a recording medium. The diluent for inkjet recording ink is characterized by containing at least isoprene glycol. 2. The diluent for ink jet recording ink according to claim 1, wherein the content of isoprene glycol is 1% by weight or more and 50% by weight or less based on the diluent. 3. An ink jet recording ink which is ejected from a nozzle to adhere onto a recording medium, wherein the ink jet recording ink contains at least isoprene glycol. 4. The inkjet recording ink according to claim 3, wherein the content of isoprene glycol is 1% by weight or more and 50% by weight or less with respect to the inkjet recording ink. 5. An ink jet recording method, wherein ink and a diluting liquid are mixed at a predetermined mixing ratio immediately before jetting to obtain a diluting ink, and the diluting ink is jetted from a nozzle to adhere onto a printing medium. The ink jet recording method, wherein the liquid contains at least isoprene glycol. 6. The ink jet recording method according to claim 5, wherein the content of isoprene glycol is 1% by weight or more and 50% by weight or less based on the diluent. 7. An inkjet recording method for ejecting ink from a nozzle to adhere onto a recording medium, wherein the inkjet recording ink contains at least isoprene glycol. 8. The inkjet recording method according to claim 7, wherein the content of isoprene glycol is 1% by weight or more and 50% by weight or less with respect to the inkjet recording ink.