JP2004238573A5 - Ink for ink jet - Google Patents

Description

【請求項７】 前記分散剤がＰＯＥ（ｎ＝４０）βナフチルエーテルであることを特徴とする請求項１乃至６の何れかに記載のインクジェット用インク。
【請求項８】 顔料が自己分散型顔料であることを特徴とする請求項１乃至３の何れかに記載のインクジェット用インク。
【請求項９】 顔料がカプセル型顔料であることを特徴とする請求項１乃至３の何れかに記載のインクジェット用インク。
【請求項１０】 前記顔料のうち、ブラック顔料がカーボンブラックであることを特徴とする請求項１乃至９の何れかに記載のインクジェット用インク。
【請求項１１】 前記顔料のうち、マゼンタ顔料がＰｉｇ．Ｒｅｄ５、７、１２、４８（Ｃａ）、４８（Ｍｎ）、５７（Ｃａ）、５７：１、１１２、１２２、１２３、１４６、１６８、１７６、１８４、１８５、２０２、Ｐｉｇ．Ｖｉｏｌｅｔ１９のうち少なくとも１種類であることを特徴とする請求項１乃至９の何れかに記載のインクジェット用インク。
【請求項１２】 前記顔料のうち、シアン顔料がＰｉｇ．Ｂｌｕｅ１、２、３、１５、１５：３、１５：４、１６、２２、６０、６３、６６のうち少なくとも１種類であることを特徴とする請求項１乃至９の何れかに記載のインクジェット用インク。
【請求項１３】 請求項１乃至１２の何れかに記載のインクジェット用インクを収容したことを特徴とするインクカートリッジ。
【請求項１４】 請求項１乃至１２の何れかに記載のインクジェット用インクを吐出させて記録を行なう方式のヘッドを備えたことを特徴とするインクジェット画像形成装置。
【請求項１５】 請求項１４に記載のインクジェット画像形成装置を用いて印字することを特徴とする画像形成方法。
【請求項１６】 請求項１５に記載の画像形成方法で印字されたことを特徴とする画像形成物。
【請求項１７】 画像支持体が紙であることを特徴とする請求項１６に記載の画像形成物。 [Claims]
An ink composition for use in an ink jet recording method, comprising at least a pigment, water, a water-soluble organic solvent, and a silicone oil emulsion, wherein the content of the silicone oil emulsion is from 1% by weight to 20% by weight. An inkjet ink, wherein the ratio of the silicone oil emulsion to pigment 1 is 0.1 or more and 20 or less.
2. The ink jet ink according to claim 1, wherein at least the average particle size of the silicone oil emulsion is larger than the average particle size of the pigment particles.
3. The inkjet ink according to claim 1, wherein the silicone oil emulsion has an average particle size of 100 nm or more.
4. The inkjet ink according to claim 1, wherein the pigment is dispersed with a dispersant.
5. The ink-jet ink according to claim 1, wherein a weight basis of the dispersant is 0.3 or more and 2 or less with respect to 1 of the pigment.
6. The ink- jet ink according to claim 1, wherein at least one of the compounds represented by the following general formula (1) is used as the dispersant.
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7. The ink-jet ink according to claim 1, wherein the dispersant is POE (n = 40) β-naphthyl ether.
8. The ink- jet ink according to claim 1, wherein the pigment is a self-dispersing pigment.
9. The ink- jet ink according to claim 1, wherein the pigment is a capsule type pigment.
10. The inkjet ink according to claim 1, wherein a black pigment among the pigments is carbon black.
11. The pigment according to claim 11, wherein the magenta pigment is Pig. Red 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 112, 122, 123, 146, 168, 176, 184, 185, 202, Pig. The inkjet ink according to claim 1, wherein the ink is at least one of Violet 19.
12. The pigment according to claim 12, wherein the cyan pigment is Pig. 10. An ink jet device according to claim 1, wherein at least one of Blue 1, 2, 3, 15, 15: 3, 15: 4, 16, 22, 60, 63, and 66 is used. ink.
13. An ink cartridge containing the ink-jet ink according to claim 1. Description:
14. An inkjet image forming apparatus, comprising: a head of a type for performing recording by discharging the inkjet ink according to claim 1. Description:
15. An image forming method, wherein printing is performed using the inkjet image forming apparatus according to claim 14.
16. An image-formed product printed by the image forming method according to claim 15. Description:
17. The image formed article according to claim 16, wherein the image support is paper.

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ink-jet ink excellent in image saturation (clearness of color tone), an ink cartridge containing the ink, an ink- jet image forming apparatus for discharging ink to perform recording, and image formation by the image forming apparatus. The present invention relates to a method and an image formed product produced by the method.

2. Description of the Related Art Conventionally, for an image output apparatus (image forming apparatus) based on an ink jet method, a mixed color using four colors obtained by adding black (K) to three colors of yellow (Y), magenta (M) and cyan (C). We have been reproducing color images. However, there is a limit to the color reproduction range in the above-described four-color mixing of yellow (Y), magenta (M), cyan (C), and black (K). In particular, color reproduction with high saturation of red (R), green (G), and blue (B), which are the respective secondary colors, is represented by a mixed color of Y, M, C, and K. It was not sufficient, and there was difficulty in color reproducibility.

To compensate for these drawbacks, an image is formed with seven color inks of R, B, and G inks in addition to the Y, M, C, and K inks to improve the color reproducibility of the secondary colors and to mix the secondary color inks. The color blur is improved (for example, see Patent Documents 6 and 7). However, the use of more inks of seven colors or more increases the number of heads at the same time, causing problems such as an increase in the cost of the image output device, an increase in size, and an increase in the maintenance load on the heads. . Further, the load on image processing for converting an image signal into an output signal increases. Such a load undesirably leads to a reduction in recording speed.
When a pigment is used as a colorant for the ink, the brightness and saturation of the printed portion are lower than when a dye is used, and the color reproducibility is generally poor. Particularly problematic is the above-mentioned secondary color, and the brightness and the saturation are greatly reduced. In an attempt to solve such problems with pigment inks, techniques using Y, M, C, K pigment inks, green (G) pigment inks, and orange (Or) pigment inks have been disclosed (for example, Patent Documents). 8), but the color reproducibility, particularly the reproducibility of red (magenta), is not sufficient.
On the other hand, it is disclosed that a problem can be solved by specifying and using a dispersant and an additive that can efficiently prepare a fine particle diameter pigment dispersion liquid that can be suitably used for an inkjet ink in a short time (for example, Patent Document 9). However, the particle diameter is in the range of 100 to 200 nm, and in order to provide a pigment ink excellent in image saturation (clearness of color tone) and ejection stability, it is necessary to reduce the particle diameter to 10 to 50 nm. There is. Conventional dispersions have generally been difficult to disperse from 10 to 50 nm due to problems such as viscosity.

[0008]
[Means for Solving the Problems]
The inventors of the present invention have conducted intensive studies and have found that by blending a physical property state of an inkjet ink and a specific emulsion, a pigment-based ink having excellent image saturation (color tone clarity), ejection stability, and ink storage stability can be obtained. The inventors have found that an inkjet ink can be obtained, and have completed the present invention.
That is, the object of the present invention is to provide (1) an ink composition used in an ink jet recording method, which comprises at least a pigment, water, a water-soluble organic solvent, and a silicone oil emulsion, wherein the content of the silicone oil emulsion is 1% by weight. % or more 20 wt% or less, ink jet ink silicone oil emulsion of the pigment 1, characterized in that 0.1 to 20, "(2)" the average particle size of at least the silicone oil emulsion pigment particles of the first (1) the inkjet ink according to claim, characterized in that larger than the average particle size ", the second is characterized in that it (3)" the average particle size of the silicone oil emulsion 100nm or more ( 1) or second (2) the inkjet ink according to Item "(4)" pigment is dispersed with a dispersing agent Characterized in that said are subsection (1), second (3) The inkjet ink according to any one of items ", (5)" by weight of the dispersant relative to the pigment 1 0.3 2 (6) The inkjet ink according to any one of (1) to (4), wherein the dispersant is a compound represented by the following general formula (1). The inkjet ink according to any one of the above items (1) to (5), wherein at least one type is used;

」、（７）「前記分散剤がＰＯＥ（ｎ＝４０）βナフチルエーテルであることを特徴とする前記第（１）項乃至第（６）項の何れかに記載のインクジェット用インク」、（８）「顔料が自己分散型顔料であることを特徴とする前記第（１）項乃至第（３）項の何れかに記載のインクジェット用インク」、（９）「顔料がカプセル型顔料であることを特徴とする前記第（１）項乃至第（３）項の何れかに記載のインクジェット用インク」、（１０）「前記顔料のうち、ブラック顔料がカーボンブラックであることを特徴とする前記第（１）項乃至第（９）項の何れかに記載のインクジェット用インク」、（１１）「前記顔料のうち、マゼンタ顔料がＰｉｇ．Ｒｅｄ５、７、１２、４８（Ｃａ）、４８（Ｍｎ）、５７（Ｃａ）、５７：１、１１２、１２２、１２３、１４６、１６８、１７６、１８４、１８５、２０２、Ｐｉｇ．Ｖｉｏｌｅｔ１９のうち少なくとも１種類であることを特徴とする前記第（１）項乃至第（９）項の何れかに記載のインクジェット用インク」、（１２）「前記顔料のうち、シアン顔料がＰｉｇ．Ｂｌｕｅ１、２、３、１５、１５：３、１５：４、１６、２２、６０、６３、６６のうち少なくとも１種類であることを特徴とする前記第（１）項乃至第（９）項の何れかに記載のインクジェット用インク」によって解決される。

(7) “The inkjet ink according to any one of (1) to (6), wherein the dispersant is POE (n = 40) β-naphthyl ether”, ( 8) “ Inkjet ink according to any one of the above items (1) to (3), wherein the pigment is a self-dispersible pigment”, (9) “The pigment is a capsule type pigment” (10) The inkjet ink according to any one of (1) to (3), wherein the black pigment is carbon black among the pigments. Ink- jet ink according to any one of Items (1) to (9) ", (11) wherein" magenta pigment is Pig. Red 5, 7, 12, 48 (Ca), 48 (Mn) ), 57 (Ca), 57: 1, 112 122,123,146,168,176,184,185,202, inkjet according to any one of paragraph (1), second (9) of this section, characterized in that at least one of the Pig.Violet19 Ink for ink ", (12)" Among the pigments, at least one kind of cyan pigment is Pig. Blue 1, 2, 3, 15, 15: 3, 15: 4, 16, 22, 60, 63, 66. The inkjet ink according to any one of the above items (1) to (9) ".

According to another aspect of the present invention, there is provided (14) a head provided with a method of performing recording by discharging the inkjet ink according to any one of the above items (1) to (12). And an inkjet image forming apparatus .

Further, the above-mentioned object is achieved by (15) an "image forming method characterized by performing printing using the inkjet image forming apparatus described in (14)" of the present invention.

Hereinafter, the present invention will be described in more detail.
The inkjet ink of the present invention is an ink composition used for an inkjet recording method containing at least a pigment, water, a water-soluble organic solvent, and a silicone oil emulsion, wherein the content of the silicone oil emulsion is 1% by weight or more and 20% by weight. In the following, the ratio of the silicone oil emulsion to the pigment 1 is 0.1 or more and 20 or less.
In the image area where the conventional inkjet ink lands on the paper and is dried on the paper and / or in the paper, a mixture of a coloring material such as a pigment and a non-volatile water-soluble organic solvent is present. ing. In particular, the pigment particles have a large variation in particle size, making it difficult to make them uniform to a specific particle size, causing irregular reflection of the pigment particles in the printed image area, and failing to provide a printed image with uniform density. Therefore, by using an appropriate amount of silicone oil emulsion, it is possible to assist the dispersion of the pigment in the ink and to re-aggregate the once dispersed fine pigment particles without adverse effects such as an increase in the viscosity of the ink liquid and aggregation of the dispersoid. Has been found to be able to be prevented, and the saturation of an image printed using this ink can be improved. This is because silicon oil emulsions have low surface tension, that is, low surface energy, so in the ink, the surface energy is reduced by touching the pigment particles to be dispersed and spreading on it in a thin film. While the surface energy is reduced by touching the shear surface of the newly generated fine particles, it is not compatible with water and the hydrophilic liquid medium, and is present as unique droplets with little adsorption to pigment particles. When printed, the surface energy is so low that it spreads over the dispersoid (pigment) in the landed ink droplets. It is unknown, and elucidation of such a mechanism is not the object of the present invention.

The silicone oil emulsion of the present invention is characterized in that the average particle size is larger than the average particle size of the pigment particles.
When the average particle size of the silicone oil emulsion is larger than the average particle size of the pigment particles, the pigment particles can be sufficiently covered with the silicone oil emulsion, and the irregular reflection preventing effect and the glossing effect of the silicone oil emulsion can be sufficiently exhibited. .
The silicone oil emulsion has an average particle size (D50) of preferably 100 nm or more and 2000 nm or less, more preferably 200 nm or more and 1500 nm or less.
If it is smaller than 100 nm, the silicone oil emulsion is insufficient to cover the pigment particles when the inkjet ink lands on the paper surface. Cannot be provided. Actually, when measuring the particle size, it is difficult to distinguish the mixture of silicone and ink because the peak of the particle size does not appear in the mixture of silicone and ink, but since the absorption wavelength is different between silicone and ink, the particle size measurement device Can be identified by changing the laser wavelength.
Here, the silicone oil emulsion is prepared by mixing a surfactant and silicone and dispersing the mixture intensely.

One form of the pigment used in the present invention is characterized by being dispersed with a dispersant. By adding the dispersant, the pigment is dispersed, the average particle diameter (D50) of the pigment particles can be reduced, and the particle diameter standard deviation can be reduced, so that a printed image with clear images and uniform density can be provided.
The weight basis of the dispersant with respect to the pigment of the inkjet ink of the present invention is preferably 0.3 or more and 2 or less, more preferably 0.5 to 2, with respect to the pigment 1. By setting the content in the range of 0.5 to 2, an ink liquid having a small average particle size and a small standard deviation in the particle size distribution can be provided. If the dispersant for the pigment is less than 0.3, satisfactory saturation cannot be obtained due to the ink liquid having a large average particle size and a large standard deviation in the particle size distribution. If it is larger than 2, the ink viscosity tends to be too high, and printing by the ink jet method tends to be difficult.

Although any dispersant may be used for the inkjet ink of the present invention, the general formula (1) can provide an inkjet ink having a small average particle size and a small standard deviation in the particle size distribution.

Another form of the pigment used in the present invention is characterized in that it is a capsule type pigment.
In order to make the pigment into a capsule type pigment, a microencapsulated pigment dispersion can be prepared by coating the pigment with an anionic group-containing organic polymer compound, and is disclosed, for example, in JP-A-9-151342. . Examples of the resin containing the colorant include a resin in which a water-insoluble colorant is encapsulated in resin microcapsules, and a resin emulsion in which a water-insoluble colorant dissolved or dispersed in an oily solvent is dispersed in an aqueous medium. However, a microencapsulated resin that is confined is particularly preferred. By using the capsule type pigment, a printed image with clear image and uniform density can be provided.

An ink cartridge containing the ink for ink jet of the present invention can be formed, and the ink is ejected from an orifice according to a recording signal by an ink jet device containing the ink cartridge, and an image is formed on a recording material, and an image is formed. A formation can be obtained.
As a means for printing using the inkjet ink of the present invention, a printing method using the above-described inkjet printer (inkjet printer) having a continuous ejection type or an on-demand type recording head can be used. In addition, as the on-demand type, for example, a piezo method, a thermal inkjet method, an electrostatic method, and the like are exemplified.
As the formation of the ink cartridge, the formation of the ink jet device, and the image forming method, known techniques in the art, such as those described in JP-A-2000-198958, can be appropriately employed.

Further, in the present invention, the recording medium (recording material) may be any of those having an absorbency for an ink composition such as paper and those substantially non-absorbable for the ink composition. Used. Specific examples of the recording medium to which the inkjet recording method according to the present invention can be applied include polyethylene terephthalate, polycarbonate, polypropylene, polyethylene, polysulfone, ABS resin, a plastic sheet based on polyvinyl chloride, brass, iron, aluminum, SUS, recording medium with metal coating on metal surface or non-metal substrate such as copper by a method such as vapor deposition, recording medium with water repellent treatment on paper as base material, and inorganic materials fired at high temperature And a recording medium made of a so-called ceramic material. Of these, paper is most preferred in terms of economy and naturalness of the image.

[0028]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. The number of parts in the examples represents parts by weight.
Ink jet inks were prepared according to the formulations of Examples 1 to 6, Comparative Example 1, and Reference Examples 1 to 8 in Table 1 below, and after stirring for 1 hour, filtered with a membrane filter having a pore size of 0.8 μm to obtain the ink of the present invention . Inks (a) to (o) were obtained.
The ink formulation method is
(I) Gly, DEG
(Ii) ECTD
(Iii) LV
(Iv) Silicon oil emulsion
(V) Distilled water is added in this order, and after stirring for about 30 minutes, a pigment seed is added, and the mixture is stirred for 30 minutes to prepare an ink jet ink.
Glycerin is abbreviated as Gly, diethylene glycol is abbreviated as DEG, polyoxyethylene (3) alkyl (C13) ether sodium acetate is abbreviated as ECTD, and Proxel LV (S) 20% solution (preservative) is abbreviated as LV.

The pigment type may be a mixture of the above-mentioned pigment (original powder ), a dispersant such as POE-β-naphthyl ether represented by the above general formula (1), and a mixture of water or a water-soluble organic solvent by a sand mill or a ball mill. , A roll mill, a bead mill, a nanomizer, a homogenizer, and the like.
The wet dispersion treatment referred to in the present invention is a process in which a mixture of a pigment, a dispersant, water and a water-soluble organic solvent is finely pulverized and dispersed by a so-called wet dispersion method such as a sand mill, a ball mill, a roll mill, a bead mill, a nanomizer, and a homogenizer.
The average particle diameter of the pigment can be controlled by the size of the beads to be put into the dispersing machine, the dispersion time, and the like. May be dispersed at 1 hour / L to 100 hours / L.
Specifically, pigment type α: used disperser DYNO-MiLL (Shinmaru Enterprises Co., Ltd.), used beads: zirconia 0.3 mm, peripheral speed: 10 m / s, flow rate: 1 L, dispersion time: 17 Time, pigment type β: used disperser DYNO-MiLL (Shinmaru Enterprises Co., Ltd.), used beads: zirconia 0.3 mm, peripheral speed: 10 m / s, flow rate: 1 L, dispersion time: 20 hours Met.