JP2005320531A - Recording ink, ink cartridge, ink record, inkjet recorder and inkjet recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain recording ink useful for inkjet recording in which dye ink is properly replaced with pigment ink by the same head. <P>SOLUTION: The recording ink is useful for inkjet recording in which dye ink is properly replaced with pigment ink by the same head and used, has -1 to 2 difference (pHA-pHB) between pH (pHA) of the dye ink and pH (pHB) of the pigment ink and ≤40 mN/m surface tension of the dye ink at 25 °C. Preferably the pH (pHA) of the dye ink is higher than pH (pHB) of the pigment ink and the pigment ink has pH 6-9 and pH buffer property. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a recording ink used for ink jet recording in which dye ink and pigment ink are appropriately exchanged with the same head, and an ink cartridge, an ink record, an ink jet recording apparatus, and an ink jet recording using the recording ink. Regarding the method.

  Ink jet printers based on the ink jet recording method are rapidly spreading in recent years because they can print on plain paper, are easy to color, are small and inexpensive, and have low running costs. In general, recording inks used in ink jet recording systems have recording image storability such as color tone to achieve high image quality, image density, and bleeding, and colorant dissolution stability to achieve reliability. Characteristics such as water resistance and light resistance for ensuring, such as quick drying of ink for achieving high speed, are required, and various proposals for satisfying these characteristics have been made. For example, Patent Document 1 proposes a pigment ink having a relatively high viscosity. In particular, when this ink is printed on plain paper at a high speed, the occurrence of feathering and color bleeding is small, and a high-quality image with a good color tone can be obtained.

However, although the proposed high-viscosity pigment ink has relatively good glossiness on glossy paper as a pigment ink, the glossiness on glossy paper is still inferior to that of dye ink. Therefore, it is required to print with a dye ink as necessary, but there is little known about a dye ink that can be printed by replacing it with a high viscosity pigment ink as needed.
For example, Patent Document 2 discloses that when an acid dye ink having a sulfonic acid group or a salt thereof and a pigment ink having an acrylic acid copolymer as a dispersant are exchanged as needed, the pH of the dye ink and the pigment ink are changed. Inkjet printers and ink sets that make the difference in pH within 1.5 have been proposed.

  However, in this proposal, the pH of the pigment ink is described as 9 to 10, and there is a description that it is not preferable that the pH of the dye ink is higher than the pH of the pigment ink. Furthermore, there is no disclosure or suggestion about the physical properties of the dye ink. In addition, in a high-concentration and high-viscosity pigment ink, if a dye ink having a pH lower than that of the pigment ink is used, the pigment ink is likely to aggregate, and an ink reservoir portion when the ink is ejected timely for stable ink ejection In addition, there is a drawback that the solid matter of the colorant tends to accumulate. This is because, in the case of pigment inks having a high concentration and a high viscosity, the pigment is easily gelled due to a decrease in pH, which is useful for obtaining a high image on the paper surface, but when mixed with a liquid having a lower pH, the ink of the printer This is because gelation or precipitation occurs in the flow path.

On the other hand, ink jet printers that use pigment inks with high viscosity are inherently prone to solidify in the ink reservoir when they are occasionally ejected in order to stably eject ink, and a scraping mechanism is provided in the idle ejection receptacle. ing.
Here, the idle discharge means an operation of discharging dirt that has entered the nozzle after the head portion is cleaned. It also means an operation of discharging the ink having a high viscosity at the nozzle part after leaving for a long time. Also, for printers that aim to print in large quantities without considering mixing with pigment ink, empty discharge is frequently required and the amount of empty discharge increases, so the empty discharge part is scraped off. It is necessary to provide a mechanism and often cause ink to flow to the waste liquid tank. In this case, there is a problem that the dye ink is dried and solidified at the discharge portion.

  Also, a droplet discharge head having a plurality of nozzle rows, and a sub tank that stores liquid supplied from a liquid storage tank and supplies liquid of each color to the droplet discharge head, the sub tank has a negative pressure A negative pressure generating means for generating air, an air opening means for opening the inside of the sub tank to the atmosphere, and a means for detecting the liquid amount, and the liquid amount detecting means can detect a resistance change due to the presence or absence of ink by an electrode. An image forming apparatus (inkjet printer) is used. However, if dye ink is used at that time, there is a problem that the ink detection operation at the electrode often becomes unstable.

  Therefore, it is used for inkjet recording where dye ink and pigment ink are exchanged as appropriate in the same head, and has excellent ejection stability and storage stability, good color tone and high image quality even when printing on plain paper at high speed. Highly sharp recorded images that do not cause blurring or blurring in the peripheral areas of density, text, and images, recording that can withstand blurring between different colors (color bleed), and images with little see-through that can withstand double-sided printing The ink for use has not been obtained yet, and its development is desired at present.

JP 2003-96345 A JP 2002-60665 A

  This invention is made | formed in view of this present condition, and makes it a subject to solve the said various problems in the past and to achieve the following objectives. That is, the present invention is used for inkjet recording in which dye ink and pigment ink are exchanged with the same head, and has excellent ejection stability and storage stability even when printing on plain paper at high speed. Color tone, high image density, text, blurred images around the image, high sharpness recording image without blurring, blurring between different colors (color bleed), and images with little show-through that can withstand double-sided printing It is an object of the present invention to provide a recording ink that can be used, an ink cartridge using the recording ink, and an ink recorded matter.

  Further, the present invention uses the recording ink of the present invention, prevents precipitation in the ink path, and the ink adheres to the empty ejection receptacle when ejecting ink in a timely manner for stable ejection, making it difficult to flow. It is an object of the present invention to provide an ink jet recording apparatus and an ink jet recording method that can prevent the ink from being destabilized and prevent the ink detection operation at the electrode from becoming unstable.

Means for solving the problems are as follows. That is,
<1> Used for inkjet recording in which the dye ink and the pigment ink are exchanged with the same head, and the difference (pHA−pHB) between the pH (pHA) of the dye ink and the pH (pHB) of the pigment ink is − The recording ink is characterized in that the dye ink has a surface tension at 25 ° C. of 40 mN / m or less.
<2> The recording ink according to <1>, wherein the pH (pHA) of the dye ink is higher than the pH (pHB) of the pigment ink.
<3> The recording ink according to any one of <1> to <2>, wherein the pigment ink has pH buffering properties in any of pH 6 to 9.
<4> The recording ink according to any one of <1> to <3>, wherein the ink viscosity at 25 ° C. of the pigment ink and the dye ink is 5 mPa · s or more.
<5> The pigment ink contains at least water, a pigment, a wetting agent, one of a polyol compound having 8 to 11 carbon atoms and a glycol ether compound, and a surfactant, and has a viscosity at 25 ° C. of 5 mPa · s or more. The ink for recording according to any one of <1> to <4>, wherein the surface tension at 25 ° C. is 40 mN / m or less.
<6> The above <5>, wherein the pigment is at least one selected from polymer fine particles containing at least one of a water-insoluble colorant and a poorly water-soluble colorant, and carbon black having at least one hydrophilic group on the surface. The recording ink described in 1.
<7> The recording ink according to any one of <1> to <6>, wherein the stability of the foam after 5 minutes based on JIS K3362 of the dye ink is less than 30 mm.
<8> The dye ink contains at least water, a dye, a wetting agent, one of a polyol compound having 8 to 11 carbon atoms and a glycol ether compound, an antifoaming agent, and a surfactant, and has a viscosity at 25 ° C. Is a recording ink according to any one of <1> to <7>, wherein the surface tension at 25 ° C. is 40 mN / m or less.
<9> The recording ink according to <8>, wherein the content of the wetting agent in the dye ink is 35 to 50% by mass.
<10> The recording ink according to any one of <8> to <9>, wherein the content of the dye in the dye ink is 4% by mass or more.
<11> The recording ink according to any one of <8> to <10>, wherein the antifoaming agent is a silicone-based antifoaming agent.
<12> The recording ink according to <11>, wherein the silicone-based antifoaming agent is any of a self-emulsifying silicone-based antifoaming agent and an emulsion-type silicone-based antifoaming agent.
<13> An ink cartridge comprising the recording ink according to any one of <1> to <12> contained in a container.
<14> At least an ink flying unit that forms an image by applying a stimulus to the recording ink according to any one of <1> to <12> and causing the recording ink to fly, and the ink flying unit In the inkjet recording apparatus, the dye ink and the pigment ink are exchanged and used with the same head.
<15> The inkjet recording apparatus according to <14>, wherein the stimulus is at least one selected from heat, pressure, vibration, and light.
<16> The above <14> to <15>, wherein the ink flying means includes a head having a plurality of nozzle rows, and a sub tank that stores liquid supplied from a liquid storage tank and supplies liquid to the head. An inkjet recording apparatus according to any one of the above.
<17> A negative pressure generating means for the sub tank to generate negative pressure in the sub tank, an atmospheric release means for releasing the inside of the sub tank to the atmosphere, and a detecting means for detecting the presence or absence of ink by a difference in electrical resistance. It is an inkjet recording device as described in said <16> which has.
<18> The inkjet recording apparatus according to any one of <14> to <17>, further including a scraping unit that scrapes off the ink fixed to the idle discharge receiver.
<19> The ink jet recording apparatus according to <18>, wherein the scraping means is either a wiper or a cutter.
<20> At least an ink flying step of forming an image by applying a stimulus to the recording ink according to any one of <1> to <12> and flying the recording ink, wherein the ink flying step includes: In the ink jet recording method, the dye ink and the pigment ink are exchanged and used in the same head.
<21> The inkjet recording method according to <20>, wherein the stimulus is at least one selected from heat, pressure, vibration, and light.
<22> An ink recorded matter comprising an image formed on the recording medium using the recording ink according to any one of <1> to <12>.

The recording ink of the present invention is used for inkjet recording in which the dye ink and the pigment ink are exchanged with the same head, and the difference (pHA) between the pH (pHA) of the dye ink and the pH (pHB) of the pigment ink. -PHB) is -1 to 2, and the surface tension of the dye ink at 25 [deg.] C. is 40 mN / m or less. In the recording ink of the present invention, when printing is performed by replacing the dye ink with timely, the occurrence of precipitation in the ink path is prevented, and it is used as an empty discharge receptacle when discharging the ink timely for stable discharge. In order to prevent the ink from precipitating and becoming difficult to flow, the pH range of the dye ink is specified, and the pH is higher than that of the pigment ink, or the difference (pHA−pHB) is set to −1 to 2 even at a low pH. In addition, by setting the surface tension of the pigment ink and the dye ink to a low surface tension of 40 mN / m or less at 25 ° C., it is possible to obtain a high-quality image having stable ejection characteristics.
In this case, the pigment ink contains at least water, a pigment, a wetting agent, one of a polyol compound having 8 to 11 carbon atoms and a glycol ether compound, and a surfactant, and has a viscosity at 25 ° C. of 5 mPa · s or more and a surface tension at 25 ° C. of 40 mN / m or less are used. As a result, an image without blurring and without blur is obtained. The dye ink contains at least water, a dye, a wetting agent, any one of a polyol compound having 8 to 11 carbon atoms and a glycol ether compound, a surfactant, and an antifoaming agent, and has a viscosity at 25 ° C. Is 5 mPa · s or more and the surface tension at 25 ° C. is 40 mN / m or less. The viscosity is preferably as high as 5 mPa · s or more. As a result, a dye ink that dries quickly, bleeds and bleeds, is glossy on glossy paper, and has excellent jetting stability after printing.

  The ink cartridge of the present invention comprises the recording ink of the present invention contained in a container. The ink cartridge is suitably used for a printer using an ink jet recording method. When recording is performed using the ink contained in the ink cartridge, the saturation is remarkably improved, the color developability is excellent, the ejection stability is high, and a high-quality image can be formed.

  The ink jet recording apparatus of the present invention has at least ink flying means for forming an image by applying energy to the recording ink of the present invention and causing the recording ink to fly, and the same head in the ink flying means The dye ink and the pigment ink are exchanged and used. In the ink jet recording apparatus, the ink flying means applies energy to the recording ink of the present invention and causes the recording ink to fly to form an image. As a result, when the dye ink and the pigment ink are exchanged in a timely manner, the saturation is remarkably improved, the color developability is excellent, the discharge stability is high, and a high-quality image can be formed. . Further, it is preferable to add an antifoaming agent to the dye ink. As a result, the sub-tank equipped with means for detecting the presence or absence of ink based on the difference in electrical resistance can stably detect the presence or absence of ink, and the instability of the sub-tank electrode sensor when using dye ink is It can be solved by adding a substance that does not generate bubbles or has a defoaming action. Further, even when the dye ink is fixed by the empty discharge receiver, it is preferable to provide a wiper or a cutter-type scraping mechanism at the empty discharge receiver. As a result, the fixed dye ink can be efficiently scraped off.

  The ink jet recording method of the present invention includes at least an ink flying process in which energy is applied to the recording ink of the present invention to cause the recording ink to fly to form an image, and the ink flying process uses the same head. Exchange dye ink and pigment ink. In the ink jet recording method, in the ink flying step, energy is applied to the recording ink of the present invention, and the recording ink is ejected to form an image. As a result, when the dye ink and the pigment ink are exchanged in a timely manner, the saturation is remarkably improved, the color developability is excellent, the discharge stability is high, and a high-quality image can be formed. .

  The ink recorded matter of the present invention has an image formed on the recording medium using the recording ink of the present invention. In the ink recorded matter, the saturation is remarkably improved, the color developability is excellent, and a high-quality image is held on the recording medium.

  In the present specification, “same head” means that at least the same head is used in the same ink jet recording apparatus, and dye ink and pigment ink are used as appropriate. However, a part of the ink jet recording apparatus includes a case where a separate one is used. For example, the cartridge includes a case where a dye ink and a pigment ink are exclusively used. It also includes the case where only the pigment ink is printed and then the cartridge is refilled with dye ink and printed (including the case where cleaning is performed at the time of replacement). In short, “same head” means to include all cases where the pigment ink and the dye ink are mixed even in a small amount in the ink passage (including the portion where the waste liquid is accumulated) in the ink jet recording apparatus. .

  According to the present invention, the conventional problems can be solved, and in the ink jet recording in which the dye ink and the pigment ink are appropriately exchanged by using the same head, the dye ink and the pigment ink can be used by exchanging the dye ink and the pigment ink as appropriate. Recording ink which is improved, has excellent color developability, has high ejection stability and is capable of forming a high-quality image, and an ink cartridge, an ink recorded matter, and an ink jet using the recording ink A recording apparatus and an ink jet recording method can be provided.

(Ink for recording)
The recording ink of the present invention is used for inkjet recording in which the dye ink and the pigment ink are exchanged with the same head, and the difference (pHA) between the pH (pHA) of the dye ink and the pH (pHB) of the pigment ink. -PHB) is -1 to 2, and the surface tension of the dye ink at 25 [deg.] C. is 40 mN / m or less.

Here, the pigment ink was once adjusted to a high pH by adding an alkali, and then titrated with an appropriate concentration of acid (adjusted by the concentration of the ion dissociation component) to obtain a titration curve.
Specifically, 50 g of the magenta pigment ink of Production Example 1 of an Example described later was raised in pH with sodium hydroxide, and then titrated with 0.25N HCl (the horizontal axis was ml). The results are shown in FIG.

From the results shown in FIG. 1, in the case of the magenta pigment ink, it can be seen that the ion dissociation constant is in the vicinity of pH 7.5 to 7.7, and at least pH = 6 to 9 has pH buffering property. That is, the hydrophilic group of the pigment dispersion is half non-dissociated around pH 7.5.
The initial pH of the magenta pigment ink was 8.7 for the ink at this time, and it was found that large particle diameters increased when the pH was 8 or less by addition of acid. It was found that when the pH was 6 or less and the pH was lower than the buffer region, it completely settled. This is partly because the magenta pigment ink originally has a high pigment concentration and high viscosity. Therefore, when magenta pigment ink adheres to paper, it is advantageous to increase the particle size (also gelling) quickly due to the components of the paper. As soon as it comes, large particles (precipitation) occur in the ink passage.
Further, the pH buffering property of yellow pigment ink is similar to that of magenta pigment ink (see FIG. 2). The cyan pigment ink also has the same pH buffering property.

  As shown in FIG. 3, for example, a dye ink having an ion dissociation constant at pH = 9.3 (for example, the yellow dye ink of Production Example 2 in the example) has a buffering property up to at least about pH 7.5. If the pH of the dye ink to be replaced as needed is set to a pH lower than 1.5 than the pH of the pigment ink = 8.7, if this is mixed with the pigment ink of the previous pH = 8.7, protons move to the pigment ink and the pigment ink The ink dissolving ability is reduced. On the other hand, if the dye ink is set to a pH higher than that of the pigment ink, the dye ink can be exchanged with the corresponding pigment ink at any time without precipitation of the pigment ink. The dye ink itself has an appropriate solubility on both the low pH side and the high pH side of this buffer region (because there is a sulfone group that ionically dissociates at a much lower pH). However, in consideration of the liquid contact property of the head member, the dye ink cannot be set to a very high pH.

From the above results, in the recording ink of the present invention, the difference (pHA-pHB) between the pH (pHA) of the dye ink and the pH (pHB) of the pigment ink is -1 to 2, and 0 to 2 is More preferred. When the pH difference is −1 to 2, when used for ink jet recording in which the dye ink and the pigment ink are exchanged with the same head, it is possible to prevent the occurrence of precipitation in the ink path, and the ink is timely for stable ejection. It is possible to prevent ink from precipitating and becoming difficult to flow in the empty discharge receptacle when the ink is discharged.
The pH (pHA) of the dye ink is preferably higher than the pH (pHB) of the pigment ink. If the pH (pHA) of the dye ink is higher than the pH (pHB) of the pigment ink, precipitation will occur in the ink path, and the ink will precipitate in the empty discharge receptacle when ejecting ink in a timely manner for stable discharge. This makes it possible to prevent dangers that are difficult to flow. That is, if the pH difference (pHA-pHB) is -1 to 0, it cannot be used, but 0 or more is preferable.
As described above, since the pigment ink is a pigment ink of the present invention that has pH buffering property in any of pH 6 to 9 and dispersibility thereof changes, the pH of the dye ink is changed as described above. It is necessary to prescribe. It should be noted that the ink having pH buffering properties in any of the ranges of pH 6 to 9 in which the dispersibility is changed is alkaline as the ink and has good dispersibility, and can be quickly neutral even after adhering to the paper surface. It has the effect of aggregating and improving the image.

The surface tension of the dye ink at 25 ° C. is 40 mN / m or less, and more preferably 35 mN / m or less. When the surface tension exceeds 40 mN / m, it is difficult for the ink in the ink discharge portion to flow, and it is likely to stay in the discharge portion, and it may be difficult to flow to the waste liquid tank. Further, when the surface tension is too high, there is a disadvantage that the drying speed of the image is slow and feathering is likely to occur.
The surface tension of the pigment ink at 25 ° C. is preferably 40 mN / m or less, and more preferably 35 mN / m or less. When the surface tension exceeds 40 mN / m, it is difficult for the ink in the ink discharge portion to flow, and it is likely to stay in the discharge portion, and it may be difficult to flow to the waste liquid tank. Further, when the surface tension is too high, there is a disadvantage that the drying speed of the image is slow and feathering is likely to occur.
The surface tension (static) can be measured, for example, by a platinum plate method using a surface tension measuring device (CBVP-Z, manufactured by Kyowa Interface Science Co., Ltd.).

The viscosity of the dye ink and pigment ink at 25 ° C. is preferably 5 mPa · s or more, and more preferably 8 mPa · s or more. When the viscosity is less than 5 mPa · s, the image density is lowered, feathering may occur, the back-through may increase, and the particle formation may become unstable. However, even when a dye ink having a lower viscosity, for example, a viscosity at 25 ° C. of about 3 mPa · s, is used, the object and effects of the present invention can be achieved as long as the pH difference (pHA−pHB) is within the above range. .
Here, the viscosity can be measured by, for example, a conical plate type rotational viscometer.

  The stability of the foam after 5 minutes based on JIS K3362 of the dye ink is preferably less than 30 mm, more preferably 10 mm or less. If the stability of the bubbles is 30 mm or more, the bubbles are difficult to disappear, and the ink supply operation of the sub tank may become unstable, or clogging due to bubbles may occur.

<Dye ink>
As described above, the dye ink is not particularly limited as long as the pH difference (pHA-pHB) from the pigment ink used for timely replacement is -1 to 2, and the surface tension at 25 ° C is 40 mN / m or less. However, for example, at least water, a dye, a wetting agent, a polyol compound having 8 to 11 carbon atoms and a glycol ether compound, a surfactant, and an antifoaming agent can be selected. It contains an agent, and further contains other components as necessary. In order to improve the image, the viscosity at 25 ° C. is preferably 5 mPa · s or more.
Regarding the pH (pHA) of the dye ink, the pH difference (pHA-pHB) from the pH (pHB) of the pigment ink is −1 to 2, the upper limit is pH = 11, and the lower limit is pH7. . When the pH exceeds 11, the wettability may be deteriorated, and the lower limit of the pH of the pigment ink is 8. Therefore, the pH of the dye ink is 7 or more to prevent precipitation when mixed with the pigment ink. .

-Dye-
There is no restriction | limiting in particular as said dye, According to the objective, it can select suitably, For example, an acidic dye, a direct dye, a basic dye, a reactive dye etc. are mentioned.

  There is no restriction | limiting in particular as said acidic dye, According to the objective, it can select suitably, What is known as a food dye, etc. are mentioned, For example, C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142; C.I. I. Acid Red 1, 8, 13, 14, 18, 26, 27, 35, 37, 42, 52, 82, 87, 89, 92, 97, 106, 111, 114, 115, 134, 186, 249, 254 289; C.I. I. Acid Blue 9, 29, 45, 92, 249; I. Acid Black 1, 2, 7, 24, 26, 94; I. Food Yellow 2, 3, 4; C.I. I. Food Red 7, 9, 14; C.I. I. Food black 1, 2, etc. are mentioned.

  The direct dye is not particularly limited and may be appropriately selected depending on the intended purpose. I. Direct yellow 1, 12, 24, 26, 33, 44, 50, 120, 132, 142, 144, 86; I. Direct red 1, 4, 9, 13, 17, 20, 28, 31, 39, 80, 81, 83, 89, 225, 227; I. Direct orange 26, 29, 62, 102; I. Direct Blue 1, 2, 6, 15, 22, 25, 71, 76, 79, 86, 87, 90, 98, 163, 165, 199, 202; C.I. I. Direct black 19, 22, 32, 38, 51, 56, 71, 74, 75, 77, 154, 168, 171 and the like.

  There is no restriction | limiting in particular as said basic dye, According to the objective, it can select suitably, For example, C.I. I. Basic Yellow 1, 2, 11, 13, 14, 15, 19, 21, 23, 24, 25, 28, 29, 32, 36, 40, 41, 45, 49, 51, 53, 63, 65, 67 70, 73, 77, 87, 91; C.I. I. Basic Red 2, 12, 13, 14, 15, 18, 22, 23, 24, 27, 29, 35, 36, 38, 39, 46, 49, 51, 52, 54, 59, 68, 69, 70 73, 78, 82, 102, 104, 109, 112; I. Basic Blue 1, 3, 5, 7, 9, 21, 22, 26, 35, 41, 45, 47, 54, 62, 65, 66, 67, 69, 75, 77, 78, 89, 92, 93 105, 117, 120, 122, 124, 129, 137, 141, 147, 155; I. Basic black 2, 8, etc. are mentioned.

  There is no restriction | limiting in particular as said reactive dye, According to the objective, it can select suitably, For example, C.I. I. Reactive Black 3, 4, 7, 11, 12, 17; C.I. I. Reactive Yellow 1, 5, 11, 13, 14, 20, 21, 22, 25, 40, 47, 51, 55, 65, 67; C.I. I. Reactive Red 1, 14, 17, 25, 26, 32, 37, 44, 46, 55, 60, 66, 74, 79, 96, 97; C.I. I. Reactive blue 1, 2, 7, 14, 15, 23, 32, 35, 38, 41, 63, 80, 95, and the like.

Among these, an anionic dye that does not cause precipitation with an anionic pigment having a negative zeta potential is particularly preferable.
The content of the dye in the dye ink is preferably 4% by mass or more, and more preferably 4 to 15% by mass. When the content is less than 4% by mass, the image density may be lowered. However, even in the case of a lower dye concentration, for example, 2% by mass, the object and effects of the present invention can be achieved if the pH difference from the pigment ink (pHA-pHB) is -1 to 2.

-Wetting agent (high boiling water-soluble organic solvent)-
The wetting agent (high-boiling water-soluble organic solvent) is not particularly limited and may be appropriately selected depending on the intended purpose. For example, glycerin, 1,3-butanediol, triethylene glycol, 1,6-hexane Preferable examples include at least one selected from diol, propylene glycol, 1,5-pentanediol, diethylene glycol, dipropylene glycol, trimethylolpropane, 1.1.1-tris (hydroxymethyl) propane, and trimethylolethane. Among these, when glycerin and a wetting agent other than glycerin are used in combination, a dye ink having a high viscosity can be achieved.

  The content of the wetting agent (high-boiling water-soluble organic solvent) in the dye ink is preferably 35 to 50% by mass when producing a high-viscosity ink, but need not be in the range when producing a low-viscosity ink. .

  As the surfactant, for example, an anionic surfactant or a nonionic surfactant is preferable, and those represented by the following general formulas (1) to (6) are preferable.

^{_{R 1 -O- (CH 2 CH 2}} O) h CH 2 COOM ··· formula (1)
However, in said general formula (1), R < ¹ > represents an alkyl group and the C6-C14 alkyl group which may be branched is suitable. h represents an integer of 3 to 12. M represents one selected from alkali metal ions, quaternary ammonium, quaternary phosphonium, and alkanolamine.

ただし、前記一般式（２）中、Ｒ^２は、アルキル基を表し、炭素数５〜１６の分岐したアルキル基を表す。Ｍは、アルカリ金属イオン、第４級アンモニウム、第４級ホスホニウム、及びアルカノールアミンから選択されるいずれかを表す。

In the general formula (2), ^{R 2} represents an alkyl group, a branched alkyl group having 5 to 16 carbon atoms. M represents one selected from alkali metal ions, quaternary ammonium, quaternary phosphonium, and alkanolamine.

ただし、前記一般式（３）中、Ｒ^３は、炭化水素基を表し、例えば、分岐してもよい炭素数６〜１４のアルキル基などが挙げられる。ｋは５〜２０の整数を表す。

In the general formula (3), R ³ represents a hydrocarbon group, for example, branched like alkyl group having 6 to 14 carbon atoms and the like even. k represents an integer of 5 to 20.

^{_{R 4 - (OCH 2 CH 2}} ) j OH ··· formula (4)
In the general formula (4), R ⁴ represents a hydrocarbon group, for example, branched 6-14 carbon atoms which may be an alkyl group, and the like. j represents an integer of 3 to 20.

ただし、前記一般式（５）及び（５’）中、Ｒ^６は、炭化水素基を表し、例えば、炭素数６〜１４のアルキル基を表す。Ｌ、ｍ、ｎ、及びｐは、１〜２０の整数を表す。

In the general formula (5) and (5 '), ^{R 6} represents a hydrocarbon group, for example, an alkyl group having 6 to 14 carbon atoms. L, m, n, and p represent an integer of 1-20.

ただし、前記一般式（６）中、ｑ及びｒは、０〜４０の整数を表す。

However, in said general formula (6), q and r represent the integer of 0-40.

-Polyol compound or glycol ether compound having 8 to 11 carbon atoms-
Examples of the polyol compound having 8 to 11 carbon atoms include 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, and the like.
Examples of the glycol ether compound include polyhydric alcohol alkyls such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. Examples of ethers include polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.
The addition amount of the polyol compound or glycol ether compound having 8 to 11 carbon atoms is preferably 0.1 to 10.0% by mass with respect to the total mass of the recording ink.

-Antifoaming agent-
There is no restriction | limiting in particular as said antifoamer, According to the objective, it can select suitably, For example, a silicone type antifoamer, a polyether type | system | group antifoamer, a fatty acid ester type | system | group antifoamer etc. are mentioned suitably. . These may be used individually by 1 type and may use 2 or more types together. Among these, a silicone type antifoaming agent is preferable at the point which is excellent in the bubble-breaking effect.

  Examples of the silicone-based antifoaming agent include oil-type silicone antifoaming agents, compound-type silicone antifoaming agents, self-emulsifying silicone antifoaming agents, emulsion-type silicone antifoaming agents, and modified silicone antifoaming agents. . Examples of the modified silicone-based antifoaming agent include amino-modified silicone antifoaming agents, carbinol-modified silicone antifoaming agents, methacrylic-modified silicone antifoaming agents, polyether-modified silicone antifoaming agents, alkyl-modified silicone antifoaming agents, and higher grades. Examples include fatty acid ester-modified silicone antifoaming agents and alkylene oxide-modified silicone antifoaming agents. Among these, the self-emulsifying type silicone antifoaming agent and the emulsion type silicone antifoaming agent are preferable in consideration of use in the recording ink which is an aqueous medium.

  Commercially available products may be used as the antifoaming agent, such as silicone antifoaming agents (KS508, KS531, KM72, KM85, etc.) manufactured by Shin-Etsu Chemical Co., Ltd., Toray Dow Corning Co., Ltd. Company-made silicone antifoaming agents (Q2-3183A, SH5510, etc.), Nihon Unicar Corporation silicone antifoaming agents (SAG30 etc.), Asahi Denka Kogyo Co., Ltd. antifoaming agents (Adecanate series, etc.), etc. Can be mentioned.

There is no restriction | limiting in particular as content in the said dye ink of the said antifoamer, According to the objective, it can select suitably, For example, 0.001-3 mass% is preferable, 0.05-0.5 mass % Is more preferable.
When the antifoaming agent is contained in the dye ink, it is particularly excellent in storage stability and ejection stability over time, and when the content is less than 0.001% by mass, the content effect is not sufficient. If it exceeds 3% by mass, clogging is likely to occur, and the reliability of the dye ink may deteriorate.

<Pigment ink>
As described above, the pigment ink is not particularly limited as long as the viscosity at 25 ° C. is 5 mPa · s or more and the surface tension at 25 ° C. is 40 mN / m or less, and may be appropriately selected according to the purpose. For example, it contains at least water, a pigment, a wetting agent, one of a polyol compound having 8 to 11 carbon atoms and a glycol ether compound, and a surfactant, and further contains other components as necessary. It contains. In addition to the condition that the difference (pHA-pHB) between the pH (pHA) of the dye ink and the pH (pHB) of the pigment ink is −1 to 2, the upper limit is pH = 11, and the lower limit is pH = 8. is there. When the pH exceeds 11, the liquid contact property is clearly deteriorated. When the pH is less than 8, the dispersion stability of the pigment ink itself may be deteriorated.

-Pigment-
The pigment is preferably at least one selected from polymer fine particles containing at least one of a water-insoluble colorant and a poorly water-soluble colorant, and carbon black having at least one hydrophilic group on the surface.
In this case, it is not necessary that all the coloring material blended in the pigment ink is encapsulated or adsorbed in the polymer fine particles, and the coloring material may be dispersed in the emulsion as long as the effects of the present invention are not impaired. Good. The color material is not particularly limited as long as it is water-insoluble or hardly water-soluble and can be adsorbed by the polymer, and can be appropriately selected according to the purpose.
Here, in the present specification, “water-insoluble or poorly water-soluble” means that the coloring material does not dissolve 10 parts by mass or more with respect to 100 parts by mass of water at 20 ° C. Further, “dissolve” means that separation or sedimentation of the coloring material is not observed in the surface layer or the lower layer of the aqueous solution visually.

  As the polymer that forms the polymer emulsion, for example, vinyl polymers, polyester polymers, polyurethane polymers, and the like can be used. Particularly preferred polymers are vinyl polymers and polyester polymers, and specific examples thereof include those disclosed in JP-A Nos. 2000-53897 and 2001-139849.

  Examples of the color material include carbon black as a black pigment. Examples of the color pigment include phthalocyanine blue, phthalocyanine green, quinacridone, anthraquinone, diazo, monoazo, pyrantrone, pyrylene, heterocyclic yellow, (thio) indigoid, and the like. Examples of the phthalocyanine blue include copper phthalocyanine blue or a derivative thereof (Pigment Blue 15). Examples of the quinacridone include Pigment Orange 48, Pigment Orange 49, Pigment Red 122, Pigment Red 192, Pigment Red 202, Pigment Red 206, Pigment Red 207, Pigment Red 209, Pigment Violet 19 and Pigment Violet 42. . Examples of the anthraquinone include pigment red 43, pigment red 194 (perinone red), pigment red 216 (brominated pyrantron red), and pigment red 226 (pyrantron red). Examples of the pyrerin include Pigment Red 123 (Bell Million), Pigment Red 149 (Scarlet), Pigment Red 179 (Maroon), Pigment Red 190 (Red), Pigment Violet, Pigment Red 189 (Yellow Shade Red), and Pigment Red. 224 and the like. Examples of the (thio) indigoid include Pigment Red 86, Pigment Red 87, Pigment Red 88, Pigment Red 181, Pigment Red 198, Pigment Violet 36, and Pigment Violet 38. Examples of the heterocyclic yellow include pigment yellow 117 and pigment yellow 138. Other suitable coloring pigments are described in, for example, The Color Index, Third Edition (The SOCIETY Of Dyer and Colorists, 1982).

  In the black pigment ink, a color pigment that can be stably dispersed without using a dispersant in which at least one hydrophilic group is bonded to the surface of carbon black directly or through another atomic group is suitably used. Use. As a result, unlike the conventional ink, a dispersing agent for dispersing the carbon black becomes unnecessary. As the carbon black used in the present invention, those having ionicity are preferable, and those having an anionic charge and those charged in a cationic form are suitable.

Examples of the anionic hydrophilic group, for _{example, -COOM, -SO 3 M, -PO} 3 HM, -PO 3 M 2, -SO 2 NH 2, -SO 2 NHCOR ( although, M in the formula is hydrogen R represents an alkyl group having 1 to 12 carbon atoms, a phenyl group which may have a substituent or a naphthyl group which may have a substituent. Etc. Among these, it is preferable to use those in which —COOM and —SO ₃ M are bonded to the surface of the color pigment.

  Further, “M” in the hydrophilic group includes, for example, lithium, sodium, potassium and the like as an alkali metal. Examples of the organic ammonium include mono to trimethyl ammonium, mono to triethyl ammonium, and mono to trimethanol ammonium. As a method of obtaining the anionically charged color pigment, as a method of introducing —COONa to the color pigment surface, for example, a method of oxidizing the color pigment with sodium hypochlorite, a method of sulfonation, a diazonium salt The method of making it react is mentioned.

-Wetting agent-
There is no restriction | limiting in particular as said wetting agent, According to the objective, it can select suitably, For example, the thing similar to the said dye ink can be used.
The amount of the wetting agent added to the pigment ink is preferably 5 to 50% by mass, and more preferably 8 to 30% by mass.

-Polyol compound or glycol ether compound having 8 to 11 carbon atoms-
There is no restriction | limiting in particular as either the said C8-C11 polyol compound and glycol ether compound, According to the objective, it can select suitably, The thing similar to the said dye ink can be used.

-Surfactant-
The surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include amphoteric surfactants, anionic surfactants, cationic surfactants, and nonionic surfactants. Can be mentioned. These may be used individually by 1 type and may use 2 or more types together.

Examples of the amphoteric surfactant include alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine, N-alkyl-N, N-dimethylammonium betaine, and the like.
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, laurate, polyoxyethylene alkyl ether sulfate salt, and the like.
Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylphenyl ether, polyoxyethylene alkylamine, polyoxyethylene alkylamide, and the like. Is mentioned. As the nonionic surfactant, an acetylene glycol surfactant can also be used. Examples of the acetylene glycol surfactant include 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3, An acetylene glycol type such as 5-dimethyl-1-hexyn-3-ol (for example, Surfynol 104, 82, 465, 485, or TG from Air Products (USA)) can be used. In particular, Surfinol 465, 104 and TG show good print quality.
Examples of the cationic surfactant include alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt type surfactants such as imidazoline, alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, And quaternary ammonium salt surfactants such as pyridinium salts, alkylisoquinolinium salts, and benzethonium chloride.

  As the surfactant, a fluorine-containing surfactant may be used. The fluorine-containing surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. Anionic having a fluoroalkyl group A surfactant, a cationic surfactant having a fluoroalkyl group, and the like are suitable.

  The pigment ink may contain an antifoaming agent, and the same antifoaming agent as that of the dye ink can be used.

-Other ingredients-
The dye ink and the pigment ink may contain other components as necessary. The other components are not particularly limited and may be appropriately selected depending on the purpose. For example, antiseptic / antifungal agents, pH adjusters, rust inhibitors, antioxidants, ultraviolet absorbers, oxygen absorbers, And light stabilizers.

  The antiseptic / antifungal agent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include sodium dehydroacetate, sodium sorbate, 2-pyridinethiol-1-oxide sodium, sodium benzoate, pentachloro Phenol sodium, etc. are mentioned, and among these, 1,2-benzisothiazolin-3-one is particularly preferably used.

  The pH adjuster is not particularly limited, and any substance can be used according to the purpose. Examples thereof include amines such as diethanolamine and triethanolamine, lithium hydroxide, sodium hydroxide, potassium hydroxide and the like. Examples include alkali metal hydroxides; ammonium hydroxide, quaternary ammonium hydroxides, quaternary phosphonium hydroxides, alkali metal carbonates such as lithium carbonate, sodium carbonate, and potassium carbonate. Among these, 2-amino-2-ethyl-1,3-propanediol is particularly preferably used. This pH adjuster is water-soluble and dissolves uniformly when added to the recording ink, and has no adverse effect on the colorant that is dispersed and dissolved.

  The rust inhibitor is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium. Nitrite and the like.

There is no restriction | limiting in particular as said antioxidant, According to the objective, it can select suitably, For example, a phenolic antioxidant (a hindered phenolic antioxidant is included), an amine antioxidant, sulfur type | system | group Antioxidants, phosphorus antioxidants, and the like can be mentioned.
Examples of the phenolic antioxidants (including hindered phenolic antioxidants) include butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, stearyl-β- (3,5 -Di-tert-butyl-4-hydroxyphenyl) propionate, 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 4,4′-Butylidenebis (3-methyl-6-tert-butylphenol), 3,9-bis [1,1-dimethyl-2- [β- (3-tert-butyl-4-hydroxy-5-methylphenyl) ) Propionyloxy] ethyl] 2,4,8,10-tetrixaspiro [5,5] undecane, 1,1,3-tris (2-methyl-4- Hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl- [methylene-3- (3 ′, 5′-di-tert-butyl-4′-hydroxypheni2,4,6-tris ( 3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tetrakisl) propionate] methane, and the like.
Examples of the amine-based antioxidant include phenyl-β-naphthylamine, α-naphthylamine, N, N′-di-sec-butyl-p-phenylenediamine, phenothiazine, N, N′-diphenyl-p-phenylenediamine. 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butylphenol, 2,4-dimethyl-6-tert-butyl-phenol, butylhydroxyanisole, 2,2′-methylenebis ( 4-methyl-6-tert-butylphenol), 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), 4,4′-thiobis (3-methyl-6-tert-butylphenol), tetrakis [methylene -3 (3,5-di-tert-butyl-4-dihydroxyphenyl) propionate] methane, 1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane and the like.
Examples of the sulfur-based antioxidant include dilauryl 3,3′-thiodipropionate, distearyl thiodipropionate, lauryl stearyl thiodipropionate, dimyristyl 3,3′-thiodipropionate, distearyl β. , β′-thiodipropionate, 2-mercaptobenzimidazole, dilauryl sulfide and the like.
Examples of the phosphorus antioxidant include triphenyl phosphite, octadecyl phosphite, triisodecyl phosphite, trilauryl trithiophosphite, trinonylphenyl phosphite, and the like.

Examples of the ultraviolet absorber include a benzophenone ultraviolet absorber, a benzotriazole ultraviolet absorber, a salicylate ultraviolet absorber, a cyanoacrylate ultraviolet absorber, and a nickel complex ultraviolet absorber.
Examples of the benzophenone-based ultraviolet absorber include 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-n-dodecyloxybenzophenone, 2,4-dihydroxybenzophenone, and 2-hydroxy-4-methoxybenzophenone. 2,2 ′, 4,4′-tetrahydroxybenzophenone, and the like.
Examples of the benzotriazole ultraviolet absorber include 2- (2′-hydroxy-5′-tert-octylphenyl) benzotriazole, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-4′-octoxyphenyl) benzotriazole, 2- (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole, and the like.
Examples of the salicylate-based ultraviolet absorber include phenyl salicylate, p-tert-butylphenyl salicylate, p-octylphenyl salicylate, and the like.
Examples of the cyanoacrylate-based ultraviolet absorber include ethyl-2-cyano-3,3′-diphenyl acrylate, methyl-2-cyano-3-methyl-3- (p-methoxyphenyl) acrylate, and butyl-2- And cyano-3-methyl-3- (p-methoxyphenyl) acrylate.
Examples of the nickel complex-based ultraviolet absorber include nickel bis (octylphenyl) sulfide, 2,2′-thiobis (4-tert-octylferrate) -n-butylamine nickel (II), and 2,2′-thiobis. (4-tert-octyl ferrate) -2-ethylhexylamine nickel (II), 2,2′-thiobis (4-tert-octyl ferrate) triethanolamine nickel (II), and the like.

  There is no restriction | limiting in particular as coloring of the recording ink of this invention, According to the objective, it can select suitably, Yellow, magenta, cyan, black etc. are mentioned. When recording is performed using an ink set in which two or more of these colorings are used in combination, a multicolor image can be formed. When recording is performed using an ink set in which all colors are combined, a full color image is formed. be able to.

  The recording ink of the present invention is used for inkjet recording in which dye ink and pigment ink are appropriately exchanged in the same head, and the head uses a piezoelectric element as pressure generating means for pressurizing ink in the ink flow path. A so-called piezo-type device (see Japanese Patent Laid-Open No. 2-51734) or a heating resistor that deforms the diaphragm that forms the wall surface of the ink flow path to change the volume of the ink flow path to eject ink droplets. A so-called thermal type that generates bubbles by heating ink in the ink flow path using the ink (see Japanese Patent Application Laid-Open No. 61-59911), and the diaphragm and the electrode that form the wall surface of the ink flow path are opposed to each other In addition, an electrostatic type that discharges ink droplets by changing the volume of the ink flow path by deforming the vibration plate by an electrostatic force generated between the vibration plate and the electrode (Japanese Patent Laid-Open No. Hei 6-1994). (See Japanese Patent No. 71882), etc., and can be used satisfactorily for a printer equipped with any inkjet head.

  The recording ink of the present invention can be suitably used in various fields, and can be suitably used in an image forming apparatus (printer or the like) based on an ink jet recording method. The recording ink is heated at 50 to 200 ° C. and can be used for a printer or the like having a function of accelerating print fixing. The following ink cartridge, ink recorded matter, ink jet recording apparatus, and ink jet recording method of the present invention It can be particularly preferably used.

(ink cartridge)
The ink cartridge of the present invention contains the recording ink of the present invention in a container, and further includes other members and the like appropriately selected as necessary.
The container is not particularly limited, and its shape, structure, size, material and the like can be appropriately selected according to the purpose. For example, at least an ink bag formed of an aluminum laminate film, a resin film, or the like Preferred examples include those possessed.
The amount of ink contained in the ink cartridge is preferably 15 g or more. When the amount is less than 15 g, when the number of printed sheets is large as in the ink jet recording apparatus of the present invention, the cartridge replacement frequency increases, and the object and effects of the present invention may not be achieved. Further, according to the ink jet recording apparatus of the present invention, even when such a large-capacity ink tank is used, the liquid contact is poor due to storage and air leakage occurs and bubbles are not generated.

Next, the ink cartridge will be described with reference to FIGS. Here, FIG. 4 is a view showing an example of the ink cartridge of the present invention, and FIG. 5 is a view including a case (exterior) of the ink cartridge of FIG.
As shown in FIG. 4, the ink cartridge 10 is filled into the ink bag 41 from the ink inlet 42 and exhausted, and then the ink inlet 42 is closed by fusion. When in use, the needle of the apparatus main body is inserted into the ink discharge port 43 made of a rubber member and supplied to the apparatus.
The ink bag 41 is formed of a packaging member such as a non-permeable aluminum laminate film. As shown in FIG. 5, the ink bag 41 is usually housed in a plastic cartridge case 44 and is detachably mounted on various ink jet recording apparatuses.

(Inkjet recording apparatus and inkjet recording method)
The ink jet recording apparatus of the present invention includes at least ink flying means, and further includes other means appropriately selected as necessary, for example, stimulus generation means, control means, etc. And pigment ink are used as appropriate.
The ink jet recording method of the present invention includes at least an ink flying step, and further includes other steps appropriately selected as necessary, for example, a stimulus generation step, a control step, and the like. It is used by replacing as appropriate.
The ink jet recording method of the present invention can be preferably carried out by the ink jet recording apparatus of the present invention, and the ink flying step can be suitably carried out by the ink flying means. Moreover, the said other process can be suitably performed by the said other means.

-Ink flying process and ink flying means-
The ink flying step is a step of forming an image by applying a stimulus to the recording ink of the present invention and causing the recording ink to fly.
The ink flying means is means for forming an image by applying a stimulus to the recording ink of the present invention and causing the recording ink to fly. The ink flying means is not particularly limited and may be appropriately selected according to the purpose. Examples thereof include various heads (ink discharge heads), and particularly a head having a plurality of nozzle rows and a liquid storage device. It is preferable to have a sub-tank that contains the liquid supplied from the tank and supplies the liquid to the head.
The sub tank includes a negative pressure generating means for generating a negative pressure in the sub tank, an air releasing means for releasing the inside of the sub tank to the atmosphere, and a detecting means for detecting the presence or absence of ink by a difference in electric resistance. What has is preferable.

  The stimulus can be generated, for example, by the stimulus generating means, and the stimulus is not particularly limited and can be appropriately selected according to the purpose, such as heat (temperature), pressure, vibration, light, etc. Is mentioned. These may be used individually by 1 type and may use 2 or more types together. Among these, heat and pressure are preferable.

  Examples of the stimulus generating means include a heating device, a pressurizing device, a piezoelectric element, a vibration generating device, an ultrasonic oscillator, a light, and the like. Specifically, for example, a piezoelectric actuator such as a piezoelectric element, Examples include thermal actuators that use phase change due to liquid film boiling using electrothermal transducers such as heating resistors, shape memory alloy actuators that use metal phase changes due to temperature changes, electrostatic actuators that use electrostatic force, etc. It is done.

  There are no particular restrictions on the manner in which the recording ink flies, and it varies depending on the type of the stimulus. For example, when the stimulus is “heat”, a recording signal is output to the recording ink in the recording head. Corresponding thermal energy is applied using, for example, a thermal head, bubbles are generated in the recording ink by the thermal energy, and the recording ink is formed into droplets from the nozzle holes of the recording head by the pressure of the bubbles. And a method of discharging and jetting. Further, when the stimulus is “pressure”, for example, by applying a voltage to a piezoelectric element bonded to a position called a pressure chamber in an ink flow path in the recording head, the piezoelectric element bends and the volume of the pressure chamber is increased. And the recording ink is ejected and ejected as droplets from the nozzle holes of the recording head.

  Further, it is preferable to have a scraping means for scraping off the ink fixed to the empty discharge receptacle. As the scraping means, either a wiper or a cutter is preferable.

  The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as sequencers and computers.

  Here, one aspect of carrying out the ink jet recording method of the present invention by the ink jet recording apparatus of the present invention will be described with reference to the drawings. The ink jet recording apparatus shown in FIG. 6 stocks an apparatus main body 1, a paper feed tray 2 for loading paper mounted on the apparatus main body 1, and paper on which an image is recorded (formed) mounted on the apparatus main body 1. A paper discharge tray 3 and an ink cartridge loading unit 6. On the upper surface of the ink cartridge loading unit 6, an operation unit 7 such as operation keys and a display is arranged. The ink cartridge loading unit 6 has a front cover 8 that can be opened and closed for attaching and detaching the ink cartridge 10.

  In the apparatus main body 1, as shown in FIGS. 7 and 8, a carriage 13 is slid in the main scanning direction by a guide rod 11 and a stay 12 that are horizontally mounted on left and right side plates (not shown). The main scanning motor (not shown) moves and scans in the direction indicated by the arrow in FIG.

The carriage 13 is provided with a recording head 14 composed of four inkjet recording heads that eject recording ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). The ejection ports are arranged in a direction crossing the main scanning direction, and are mounted with the ink droplet ejection direction facing downward.
The inkjet recording head constituting the recording head 14 includes a piezoelectric actuator such as a piezoelectric element, a thermal actuator that uses a phase change caused by liquid film boiling using an electrothermal transducer such as a heating resistor, and a metal phase caused by a temperature change. A shape memory alloy actuator using a change, an electrostatic actuator using an electrostatic force, or the like as an energy generating means for discharging recording ink can be used.
In addition, the carriage 13 is equipped with a sub tank 15 for each color for supplying ink of each color to the recording head 14. The sub-tank 15 is supplied with and supplemented with the recording ink of the present invention from the ink cartridge 10 of the present invention loaded in the ink cartridge loading section 6 via a recording ink supply tube (not shown).

  On the other hand, as a paper feeding unit for feeding the paper 22 stacked on the paper stacking unit (pressure plate) 21 of the paper feeding tray 2, a half-moon roller (feeding) that separates and feeds the paper 22 one by one from the paper stacking unit 21. The paper roller 23) and a separation pad 24 made of a material having a large friction coefficient are provided opposite to the paper feed roller 23, and the separation pad 24 is urged toward the paper feed roller 23 side.

  As a transport unit for transporting the paper 22 fed from the paper feed unit below the recording head 14, a transport belt 31 for transporting the paper 22 by electrostatic adsorption and a guide 25 from the paper feed unit. The counter roller 32 for transporting the paper 22 fed via the transport belt 31 with the transport belt 31 and the paper 22 fed substantially vertically upward are changed by about 90 ° to be copied on the transport belt 31. A conveying guide 33 and a tip pressure roller 35 urged toward the conveying belt 31 by the pressing member 34, and a charging roller 36 as a charging means for charging the surface of the conveying belt 31. It has been.

  The conveyance belt 31 is an endless belt, is stretched between the conveyance roller 37 and the tension roller 38, and can circulate in the belt conveyance direction. A guide member 77 is disposed on the back side of the conveyance belt 31 so as to correspond to a printing area by the recording head 14. As a paper discharge unit for discharging the paper 22 recorded by the recording head 14, a separation claw 51 for separating the paper 22 from the conveyance belt 31, a paper discharge roller 52, and a paper discharge roller 53 are provided. The paper discharge tray 3 is disposed below the paper discharge roller 52.

  A double-sided paper feeding unit 61 is detachably attached to the back surface of the apparatus main body 1. The double-sided paper feeding unit 61 takes in the paper 22 returned by the reverse rotation of the transport belt 31, reverses it, and feeds it again between the counter roller 32 and the transport belt 31. A manual paper feed unit 62 is provided on the upper surface of the duplex paper feed unit 61.

  In this ink jet recording apparatus, the paper 22 is separated and fed one by one from the paper feed unit, and the paper 22 fed substantially vertically upward is guided by the guide 25 and between the transport belt 31 and the counter roller 32. It is sandwiched and conveyed. Further, the front end is guided by the transport guide 33 and pressed against the transport belt 31 by the front end pressure roller 35, and the transport direction is changed by approximately 90 °.

At this time, the conveyance belt 37 is charged by the charging roller 36, and the sheet 22 is conveyed by being electrostatically attracted to the conveyance belt 31. Therefore, by driving the recording head 14 according to the image signal while moving the carriage 13, ink droplets are ejected onto the stopped paper 22 to record one line, and after the paper 22 is conveyed by a predetermined amount, Record the next line. Upon receiving a recording end signal or a signal that the trailing edge of the paper 22 has reached the recording area, the recording operation is finished and the paper 22 is discharged onto the paper discharge tray 3.
Then, when it is detected that the remaining amount of recording ink in the sub tank 15 has decreased, a required amount of recording ink is supplied from the ink cartridge 10 to the sub tank 15.

  Here, an example is described in which the present invention is applied to a serial (shuttle type) ink jet recording apparatus that is scanned by a carriage, but the present invention can be similarly applied to a line type ink jet recording apparatus having a line type head.

Here, for example, as shown in FIG. 9, the recording head 14 (used to collectively refer to a plurality of heads) includes a nozzle array 14yn including a plurality of nozzles N that eject yellow (Y) ink droplets, and magenta ( M) a droplet discharge head 14 a having a nozzle row 14 mn composed of a number of nozzles N that eject ink droplets of M, a nozzle array 14 cn composed of a number of nozzles N that eject cyan (C) ink droplets, and black (Bk) ) And a head 14b having a nozzle row 14kn composed of a number of nozzles N that eject ink droplets.
In this case, two colors are supplied to one recording head from two different sub-tanks, and four colors of YMC and black are printed by two sub-tank two heads. Four heads with rows are prepared, and one different color sub-tank is prepared for each, and four heads with two nozzle rows and four sub-tanks are used to print four colors YMC and black. May be. In the examples described later, an ink jet printer (IPSiO G707 manufactured by Ricoh Co., Ltd.) having four heads having two nozzle rows was used.

  As the ink jet head constituting the recording head 14, a piezoelectric actuator such as a piezoelectric element, a thermal actuator that uses a phase change caused by film boiling of a liquid using an electrothermal transducer such as a heating resistor, and a metal phase change caused by a temperature change. A shape memory alloy actuator to be used, an electrostatic actuator using an electrostatic force, or the like as an energy generating means for discharging ink can be used. In the embodiments described later, a head using a piezoelectric actuator (piezoelectric element) as energy generating means is mounted.

  Further, the carriage 13 has a sub tank 15 which is a liquid container of each color for supplying each color ink to each nozzle row 14yn, 14mn, 14cn, 14kn of the recording head 14 (if each color is distinguished, the nozzle row The codes 15y, 15m, 15c, and 15k are used correspondingly). The sub-tank 15 uses the main tank (ink cartridge) 10 for each color described above via the ink supply tube 16 (in order to distinguish each color, the symbols 10y, 10m, 10c, and 10k are used corresponding to the nozzle rows. ) Is replenished and supplied. Here, the main tank 10 stores ink of each color of yellow (Y), cyan (C), magenta (M), and black (Bk) corresponding to each color, but the main tank 10 stores black ink. The tank 10k has a larger ink storage capacity than the main tanks 10y, 10m, and 10c that store other color inks.

Next, details of the ink supply device which is a liquid supply device in the recording apparatus will be described with reference to FIGS. 10 is an exploded perspective view of a portion related to the ink supply device, FIG. 11 is a detail thereof, and FIG. 12 is a schematic side view of the sub tank.
As described above, the ink supply device is mounted on the carriage 13 and supplies a sub tank 15 which is a liquid container for supplying ink to each recording head 14 (14a, 14b), and the sub tank 15 is supplied with ink via a supply tube 16. And a main tank (ink cartridge) 10 for supply and replenishment.
One sub tank 15 is a flexible film-like member that seals an opening (one surface of the sub tank 15) of the ink storage unit 100 to a container main body (case main body) 101 that forms the ink storage unit 100 that stores ink. (Flexible film-like member) 102 is attached by bonding or welding, and further, the film-like member 102 is biased outwardly between the case main body 101 and the film-like member 102 inside the ink containing portion 100. A spring (spring) 103 which is an elastic member is provided.

Here, the film-like member 102 may have a single layer structure, but as shown in FIG. 10A, a two-layer structure in which different types of first layer 102a and second layer 102b are laminated, for example, polyethylene and A nylon film-like member may be laminated, or a silica vapor deposition layer 102c may be formed on the first layer 102a as shown in FIG. By adopting such a configuration, it is possible to ensure liquid resistance against ink. Moreover, the liquid resistance with respect to the ink accommodated can also be improved by including a silica vapor deposition layer in the film-like member 102.
Moreover, as for the thickness of the film-like member 102, 10-100 micrometers is preferable. If the thickness is less than 10 μm, damage due to deterioration over time may easily occur, and if it exceeds 100 μm, flexibility may be reduced and efficient generation of negative pressure may be difficult.
Furthermore, a bulging portion 102a having a convex shape corresponding to the spring 103 is formed on the film-like member 102, and a reinforcing member 104 is attached to the outer surface thereof. In this manner, by providing the flexible film-like member 102 with the convex portion, the elastic member (here, the spring) 103 can be stably held. In this case, the flexible film-like member 102 can be easily formed with a convex portion by forming a sheet-like film member into a convex shape.

  Further, the case 101 is provided with an ink introduction path portion 111 for replenishing ink in the ink containing portion 100, and a connecting means for connecting the ink introduction path portion 111 and the supply tube 16 connected to the ink cartridge 10. 112 can be detachably mounted. A liquid feed pump as described later is provided between the ink cartridge 10 and the sub tank 15 in order to pressure-feed ink from the ink cartridge 10 to the sub tank 15.

  Further, a connecting member 113 for supplying ink from the ink containing portion 100 to the recording head 14 is attached to the lower portion of the case 101, and an ink supply path 114 of the recording head 14 is formed in the connecting member 113. A filter 115 is interposed between the two.

  An air flow path 121 is formed in the upper part of the case 101 for taking out air from the ink containing portion 100. The air flow path 121 includes an inlet flow path portion 122 having an opening facing the ink containing portion 100 and a flow path portion (referred to as an “orthogonal flow path portion”) 123 following the inlet flow path portion 122. An accumulation portion 126 is continuously formed in a portion that communicates with the atmosphere opening hole 131 provided in the case 101 on the downstream side, and that is further below the atmosphere opening hole 131 in use.

  The atmosphere release hole 131 is provided with an atmosphere release valve mechanism 132 which is an atmosphere release means for switching between the sealed state and the atmosphere release state in the sub tank 15. The atmosphere release valve mechanism 132 is configured by accommodating a valve seat 134, a ball 135 as a valve body, and a spring 136 for urging the ball 135 toward the valve seat 134 in a holder 133.

  The operation of the storage unit 126 will be described. When the apparatus main body is tilted or shaken, there is a high possibility that ink will enter the air flow path 121. Therefore, the ink that has entered from the air flow path 121 can be accumulated in the accumulating portion 126, and even if the ink falls and is intruded during transportation, the ink is placed in the atmosphere opening port 131 and the atmosphere opening valve mechanism 132 that opens and closes the ink. Prevents the atmosphere release valve mechanism 132 from malfunctioning due to intrusion and hardening.

  In addition, two detection electrodes 141 and 142 for detecting that the amount of ink in the sub tank 15 is equal to or less than a predetermined amount (this state is “no ink”) are attached to the upper portion of the case 101. ing. Detecting “no ink” by changing the conduction state between the detection electrodes 141 and 142 in a state where both the detection electrodes 141 and 142 are immersed in ink and in a state where at least one of the detection electrodes 141 and 142 is not immersed in ink Can do.

  As shown in FIGS. 14 and 15, the ink jet recording apparatus of the present invention maintains the nozzle state of the recording head 14 in the non-printing area on one side (or both sides) of the carriage 13 in the scanning direction. A maintenance / recovery mechanism (hereinafter also referred to as “sub-system”) 71 for recovery is arranged. FIG. 14 is a top view of the maintenance / recovery mechanism, and FIG. 15 is a schematic explanatory diagram of the maintenance unit. The subsystem 71 includes cap members 72A and 72B for capping each nozzle surface of the recording heads 14a and 14b, a wiper blade 73 for wiping the nozzle surface, and the like. Between the cap member 72 </ b> A and the wiper blade 73, there is provided an idle discharge receiver for empty discharge of ink. This empty discharge receiver is configured such that ink is discharged here and flows to the lower waste liquid tank, and the ink is easily fixed to this portion (discharged portion), so that the fixed ink is automatically scraped off. A wiper is provided. In this case, particularly when a dye ink having a high viscosity is used, it is effective for scraping off the dye ink solidified in the idle ejection portion.

  In addition, it is also effective to provide a cutter-type scraping mechanism when a dye-fixed material is accumulated. In both cases, the pigment inks of Ricoh Yipsio G707 and G505 (manufactured by Ricoh Co., Ltd.) also acted effectively on the dye ink. As described above, particularly in the case of a dye ink having a limited solubility, once it has been fixed, it has been difficult to collapse what has conventionally been accumulated. In addition, when the pigment ink and the dye ink are exchanged and used, the ink jet recording apparatus of the present invention can scrape off the mixed adhering material of the pigment ink and the dye ink.

Next, the maintenance / recovery mechanism 71 according to the ink jet recording apparatus of the present invention will be described.
As shown in FIGS. 14 and 15, first, when the motor 231 rotates forward, the motor gear 232, the pump gear 234, the intermediate gear 235, the intermediate gear 236, and the intermediate gear 237 rotate, and the tube pump 220 is activated to The rightmost (recording region side) cap connected by the tube 219 is sucked. Other gears do not operate because the one-way clutch 237 is disconnected.
When the motor 231 rotates in the reverse direction, the one-way clutch 237 is connected and the motor to the camshaft rotate. The tube pump 220 rotates in the reverse direction but does not operate as a pump.
A carriage lock cam 227, cap cams 222B and 222A, a wiper cam 224, a wiper cleaner cam 228, and a home position sensor cam 241 are attached to the cam shaft 221 so as to rotate integrally.
The carriage lock 215 is biased upward (in the locking direction) by a compression spring (not shown). The carriage lock 215 is moved up and down by the carriage lock arm 217 in contact with the cam surface of the carriage lock cam 227.
The caps 72A and 72B and the cap holder 212A are moved up and down by cap cams 222A and 222B.
The wiper 73 is moved up and down by the wiper cam 228.
The wiper cleaner 218 is biased in a direction away from the wiper 73 by a spring and is moved in the wiper direction by the wiper cleaner cam 218. The wiper 73 descends while being sandwiched between the wiper cleaner 218 and the idle ejection receptacle, whereby the ink of the wiper 73 is scraped into the idle ejection.
A sensor (photo interrupter / not shown) is fixed to the maintenance unit body. When the cap comes to the lowermost end with the home position cam, the HP lever (not shown) is operated to open the sensor (pump). The home position is detected (other than that, the HP lever is not operated and the sensor is normally closed).
When the power is turned on, the caps 72A and 72B and the cap holders 212A and 212B move up and down (the position is not detected until the movement is started), and a predetermined amount is detected after detecting the cap home position (in the middle of ascending). Move to the bottom end. Thereafter, the carriage moves left and right, returns to the cap position after position detection, and is capped.

  The order of operation when the motor reverses is as follows: cap lift (carriage lock almost simultaneously), cap lower (carriage lock almost simultaneously), home position sensor open, wiper lift, wiper cleaner start (press wiper against empty discharge receptacle), Repeat the series of actions to lower the wiper (wipe the wiper with the wiper cleaner) and return to the wiper cleaner.

  The ink jet recording apparatus and the ink jet recording method of the present invention can be applied to various types of recording by the ink jet recording method, and are particularly suitable for, for example, an ink jet recording printer, a facsimile apparatus, a copying apparatus, and a printer / fax / copier multifunction machine. Can be applied to.

(Ink record)
The ink recorded matter recorded by the ink jet recording apparatus and the ink jet recording method of the present invention is the ink recorded matter of the present invention. The ink recorded matter of the present invention has an image formed on the recording medium using the recording ink of the present invention.
There is no restriction | limiting in particular as said recording medium, According to the objective, it can select suitably, For example, a plain paper, glossy paper, special paper, cloth, a film, an OHP sheet etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together.
The ink recorded matter has high image quality, no bleeding, excellent temporal stability, and can be suitably used for various purposes as a material on which various prints or images are recorded.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Preparation Example 1)
-Preparation of copper phthalocyanine pigment-containing polymer fine particle dispersion-
A blue polymer fine particle dispersion was obtained by reexamining Preparation Example 3 disclosed in JP-A No. 2001-139849.
About the obtained polymer fine particle, the volume average particle diameter (D50%) measured with the particle size distribution analyzer (Microtrac UPA, Nikkiso Co., Ltd.) was 93 nm.

(Preparation Example 2)
-Preparation of dimethylquinacridone pigment-containing polymer fine particle dispersion-
A red-purple polymer fine particle dispersion was prepared in the same manner as in Production Example 1 except that the copper phthalocyanine pigment was changed to Pigment Pigment Red 122 in Preparation Example 1.
About the obtained polymer fine particle, the volume average particle diameter (D50%) measured with the particle size distribution analyzer (Microtrac UPA, Nikkiso Co., Ltd.) was 127 nm.

(Preparation Example 3)
-Preparation of monoazo yellow pigment-containing polymer fine particle dispersion-
A yellow polymer fine particle dispersion was prepared in the same manner as in Production Example 1 except that the copper phthalocyanine pigment was changed to Pigment Pigment Yellow 74 in Preparation Example 1.
About the obtained polymer microparticles | fine-particles, the volume average particle diameter (D50%) measured with the particle size distribution analyzer (Microtrac UPA, Nikkiso Co., Ltd.) was 76 nm.

(Preparation Example 4)
-Preparation of carbon black dispersion treated with diazo compound-
100 g of carbon black having a surface area of 230 m ² / g and a DBP oil absorption of 70 ml / 100 g and 34 g of p-amino-N-benzoic acid are mixed and dispersed in 750 g of water, and 16 g of nitric acid is added dropwise thereto to 70 Stir at ° C. After 5 minutes, a solution of 11 g of sodium nitrite dissolved in 50 g of water was added, and the mixture was further stirred for 1 hour. The resulting slurry was diluted 10 times and centrifuged to remove coarse particles, the pH was adjusted with diethanolamine to pH 8-9, desalted and concentrated with an ultrafiltration membrane to obtain a carbon black dispersion with a pigment concentration of 15%. Then, it was filtered through a polypropylene 0.5 μm filter to obtain a carbon black dispersion.
About the obtained polymer fine particle, the volume average particle diameter (D50%) measured with the particle size distribution analyzer (Microtrac UPA, Nikkiso Co., Ltd.) was 99 nm.

  Next, a pigment ink was produced using the polymer fine particle dispersion and the carbon black dispersion obtained in Preparation Examples 1 to 4.

(Production Example 1)
-Pigment ink set-
<Preparation of cyan pigment ink>
1. 10% by mass (as solids) of phthalocyanine pigment-containing polymer fine particles of Preparation Example 1, 25.0% by mass of propylene glycol, 9.5% by mass of glycerol, surfactant (nonionic surfactant: polyoxyalkylene derivative) 0% by mass, 2,2,4-trimethyl-1,3-pentanediol 2.0% by mass, benzisothiazoline preservative 0.2% by mass, silicone antifoam SAG30 (manufactured by Nihon Unicar Co., Ltd.) 0.03 An appropriate amount of mass% and ion-exchanged water was added to make 100 mass%, and the mixture was stirred. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer. Thus, a cyan pigment ink was prepared.

<Preparation of magenta pigment ink>
10.0% by mass (as solid content) of dimethylquinacridone pigment-containing polymer fine particles of Preparation Example 2, 10.0% by mass of 1,3-butanediol, 9.0% by mass of glycerol, and 2.2% by mass of nonionic surfactant , 2-ethyl-1,3-hexanediol 1.9% by mass, benzisothiazoline preservative 0.07% by mass, silicone antifoaming agent 0.03% by mass, and an appropriate amount of ion-exchanged water to 100% by mass, The mixture was stirred. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer. Thus, a magenta pigment ink was prepared.

<Preparation of yellow pigment ink>
Monoazo yellow pigment-containing polymer fine particles of Preparation Example 1 11.0% by mass (as solid content), 1,3-butanediol 20.5% by mass, glycerol 8.5% by mass, nonionic surfactant 2.1% by mass , 2-ethyl-1,3-hexanediol 1.9% by mass, benzisothiazoline preservative 0.05% by mass, silicone antifoaming agent 0.1% by mass, and ion-exchanged water are added in an appropriate amount to 100% by mass. , Mixed and stirred. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer. Thus, a yellow pigment ink was prepared.

<Preparation of black pigment ink>
Carbon black dispersion treated with the diazo compound of Preparation Example 4 10.0% by mass (as a solid content), 2,5-pentanediol 22.5% by mass, glycerol 7.5% by mass, nonionic surfactant (polyoxy) Alkylene derivatives) 1.7% by mass, 2,2,4-trimethyl-1,3-pentanediol 2.1% by mass, benzisothiazoline preservative 0.2% by mass, silicone antifoam KS531 (Shin-Etsu Chemical Co., Ltd.) (Made by company) 0.1% by mass and appropriate amount of ion-exchanged water were added to 100% by mass, and after mixing and stirring, the pH was adjusted with an organic pH adjuster. Then, it filtered with the membrane filter with an average hole diameter of 0.8 micrometer. Thus, a black pigment ink was prepared.

  The obtained cyan pigment ink, magenta pigment ink, yellow pigment ink, and black pigment ink were measured for surface tension, pH, and viscosity as follows. The results are shown in Table 1.

<Measurement of pH>
The pH was measured at 23 ° C. using METER MODEL HM3A (manufactured by Toa Denpa Kogyo Co., Ltd.).

<Measurement of viscosity>
The viscosity was measured at 25 ° C. using a RE500 viscometer (manufactured by Toki Sangyo Co., Ltd.).

<Measurement of surface tension>
The surface tension is a static surface tension measured at 25 ° C. using a platinum plate using a surface tension measuring device (CBVP-Z, manufactured by Kyowa Interface Science Co., Ltd.).

(Production Example 2)
-Dye ink set-
<Preparation of cyan dye ink>
C. I. Direct Blue 199 (solid content 10.25% by mass) 44% by mass, 1,3-butanediol 30.75% by mass, glycerin 10.25% by mass, 2,2,4-trimethyl-1,3-pentanediol 8% by mass, 2.2% by mass of a surfactant (polyoxyalkylene derivative), 0.2% by mass of a benzisothiazoline preservative, and the remainder of the water were mixed, and the pH was adjusted with an organic amine pH adjuster. Thus, a cyan dye ink was prepared.

<Preparation of magenta dye ink>
Magenta reactive dye 4.5% by mass, 1,3-butanediol 30.75% by mass, glycerin 10.25% by mass, 2-ethyl-1,3-hexanediol 1.5% by mass, surfactant (poly The oxyalkylene derivative (2.2% by mass), the benzisothiazoline preservative 0.2% by mass, and the remaining water were mixed, and the pH was adjusted with an organic amine-based pH adjuster. Thus, a magenta dye ink was prepared.

<Preparation of yellow dye ink>
C. I. Acid Yellow 23 4.5% by mass, 1,3-butanediol 30.75% by mass, glycerol 10.25% by mass, 2-ethyl-1,3-hexanediol 2% by mass, surfactant (polyoxyalkylene derivative) 2% by mass, benzisothiazoline preservative 0.2% by mass, and the remaining water were mixed, and the pH was adjusted with an organic amine-based pH adjuster. Thus, a yellow dye ink was prepared.

(Production Example 3)
-Dye ink set-
<Preparation of cyan dye ink>
C. I. Direct Blue 199 (solid content 10.25% by mass) 44% by mass, 1,3-butanediol 30.75% by mass, glycerin 10.25% by mass, 2,2,4-trimethyl-1,3-pentanediol 8% by mass, surfactant (polyoxyalkylene derivative) 2.2% by mass, benzisothiazoline preservative 0.2% by mass, silicone antifoaming agent KS531 (self-emulsifying type, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.05 The mass% and the remainder of water were mixed and the pH was adjusted with an organic amine pH adjuster. Thus, a cyan dye ink was prepared.

<Preparation of magenta dye ink>
Magenta reactive dye 4.5% by mass, 1,3-butanediol 30.75% by mass, glycerin 10.25% by mass, 2-ethyl-1,3-hexanediol 1.5% by mass, surfactant (poly Oxyalkylene derivative) 2.2% by mass, benzisothiazoline-based preservative 0.2% by mass, silicone antifoam KM72F (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.05% by mass, and the remainder of the water are mixed to form an organic amine system. The pH was adjusted with a pH adjuster. Thus, a magenta dye ink was prepared.

<Preparation of yellow dye ink>
C. I. Acid Yellow 23 4.5% by mass, 1,3-butanediol 30.75% by mass, glycerol 10.25% by mass, 2-ethyl-1,3-hexanediol 2% by mass, surfactant (polyoxyalkylene derivative) 2% by mass, benzisothiazoline preservative 0.2% by mass, silicone antifoam KM72F (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.05% by mass, and the remainder of water are mixed, and the pH is adjusted with an organic amine-based pH adjuster did. Thus, a yellow dye ink was prepared.

(Production Example 4)
-Dye ink set-
<Preparation of cyan dye ink>
C. I. Direct Blue 199 (solid content 10.25% by mass) 44% by mass, 1,3-butanediol 30.75% by mass, glycerin 10.25% by mass, benzisothiazoline preservative 0.2% by mass, and water remaining The pH was adjusted with an organic amine pH adjuster. Thus, a cyan dye ink was prepared.

<Preparation of magenta dye ink>
Mixing magenta reactive dye 4.5% by mass, 1,3-butanediol 30.75% by mass, glycerol 10.25% by mass, benzisothiazoline preservative 0.2% by mass, and the remainder of the water, and organic amine type The pH was adjusted with a pH adjuster. Thus, a magenta dye ink was prepared.

<Preparation of yellow dye ink>
C. I. Acid Yellow 23 4.5% by mass, 1,3-butanediol 30.75% by mass, glycerin 10.25% by mass, benzisothiazoline preservative 0.2% by mass, and water balance are mixed to adjust the organic amine pH. The pH was adjusted with an agent. Thus, a yellow dye ink was prepared.

  The obtained cyan dye ink, magenta dye ink, and yellow dye ink were measured for surface tension, pH, and viscosity as follows. The results are shown in Table 2.

<Measurement of pH>
The pH was measured at 23 ° C. using METER MODEL HM3A (manufactured by Toa Denpa Kogyo Co., Ltd.).

<Measurement of viscosity>
The viscosity was measured at 25 ° C. using a RE500 viscometer (manufactured by Toki Sangyo Co., Ltd.).

<Measurement of surface tension>
The surface tension is a static surface tension measured at 25 ° C. using a platinum plate using a surface tension measuring device (CBVP-Z, manufactured by Kyowa Interface Science Co., Ltd.).

(Production Example 5)
-Preparation of yellow dye ink-
A yellow dye ink was prepared in the same manner as in Production Example 2 except that the organic amine pH adjuster was not added to the yellow dye ink of Production Example 2.

(Production Example 6)
-Preparation of yellow dye ink-
A yellow dye ink was prepared in the same manner as in Production Example 2 except that acid (1N aqueous hydrochloric acid) was added to the target pH in Production Example 2.

(Production Example 7)
-Preparation of yellow dye ink-
A yellow dye ink was prepared by mixing the yellow dye ink of Production Example 5 and the yellow dye ink of Production Example 6 so that the intended pH was obtained.

  Next, with respect to the obtained Production Examples 5 to 7, the pH and the surface tension were measured in the same manner as in Production Example 2. The results are shown in Table 3.

(Examples 1-7 and Comparative Examples 1-2)
Next, as shown in Table 4 below, the dye ink and the pigment ink were separately filled in a cartridge of an ink jet printer (manufactured by Ricoh Co., Ltd., IPSiO G707).

<Evaluation>
About Examples 1-7 and Comparative Examples 1-2, using the plain paper (Ricoh Co., Ltd., plain paper type 6200) and glossy paper (Ricoh Co., Ltd., exclusive silky gloss paper), the inkjet printer (stock) The pigment ink and the dye ink were separately printed from the same head (by exchanging the cartridge each time) by Ricoh Company, IPSiO G707).
As a result, Examples 1 to 7 were able to perform high-quality printing for both the pigment ink and the dye ink. In addition, dye inks have more show-throughs on plain paper than pigment inks, and glossy papers have a glossy photographic image than pigment inks, although they are slightly inferior in light resistance and water resistance.
In Examples 1 to 7, after printing with pigment ink, about 20 ml of a vehicle (10 parts by mass of glycerin, 20 parts by mass of 1,3-butanediol, the remainder of water, and pH = 9 with sodium hydroxide) After cleaning in (adjustment), printing was performed after changing to dye ink, and clogging in the ink passage did not occur.
On the other hand, a slight amount of pigment ink remained in the idle discharge receptacle, but in Examples 1 to 7, there was little increase in fixed matter even when the dye ink and the pigment ink were appropriately replaced and printed. Further, when the pigment inks of Examples 1 to 7 were directly added to the dye inks of Examples 1 to 7, no large particles were generated.
On the other hand, in Comparative Example 1, after printing with the pigment ink, after washing with the vehicle and printing with the dye ink, many nozzle omissions that seem to be due to clogging occurred. As will be described later, when the pigment ink of Comparative Example 1 was added to the dye ink of Comparative Example 1, large particles were generated. Further, it is considered that the pigment ink cannot be completely cleaned somewhere in the passage even if it is cleaned. Of course, it gets worse without cleaning.
In Comparative Example 2, after printing with the pigment ink, printing was performed with the dye ink changed, and the ink ejection was slightly disturbed.

(Experiment)
For the yellow dye ink of Production Example 2 and the yellow dye inks of Production Examples 5 to 7, 5% by mass of the yellow pigment ink of Production Example 1 was added, and the particle size and frequency were measured using a particle size distribution measuring device (Microtrac UPA, Nikkiso Co., Ltd.). (Manufactured by company). The results are shown in FIG.

From the results of FIG. 16, in Production Example 7, the pH after addition is 0.85 lower than the pH of the pigment ink (1.05 lower in the ink before mixing), and a large particle diameter when a small amount of pigment ink is mixed. Particles are generated.
No problem arises with dye inks having a pH equal to or higher than the pH of the pigment inks of Production Examples 2 and 5.
FIG. 16 shows the case where 5% by mass of the pigment ink is added to the dye ink, but when the amount of pigment ink mixed in the dye ink is smaller, the pH of the dye ink hardly changes and the particle size of a small amount of pigment is increased. Happens. In FIG. 16, the initial pH indicates the pH of the dye ink before mixing, and the pH described before indicates the pH after mixing with the pigment ink.
On the other hand, when pigment ink and dye ink are mixed at 1: 1 (mass ratio), the pH is close to that of pigment ink, so there is no significant effect (however, when the pH is high to some extent (up to about 7.5) )).
However, in the case of ink jet recording, ink is mixed while being ejected, so there is always a place where a small amount of pigment ink and a large amount of dye ink are mixed at the time of ink replacement, and once large particles are generated at that place, the ejection reliability is affected. It is possible to do.
In addition, in the case of inkjet recording, if a portion that is not sufficiently cleaned remains even after cleaning, large particles are often generated by the addition of other inks, and jetting is often affected. However, when a dye ink having a pH higher than that of the pigment ink is used, it is recognized that large particles are not generated by mixing without washing.

<Evaluation of electrode ink detection malfunction>
The ink jet printer (IPSiO G707, manufactured by Ricoh Co., Ltd.) detects the presence or absence of ink by measuring the electrical resistance with an electrode, and fills the sub tank with ink accordingly. When the dye ink to which the antifoaming agent of Production Example 2 was not added was used, erroneous detection often occurred (when it was detected that there was no ink despite the presence of ink). The reason is presumed to be caused by ink bubbles adhering to the electrode. Therefore, when the dye ink added with 0.05% by mass of the silicone antifoaming agent of Production Example 3 was used, false detection decreased.

In addition, the dye stability inks of Production Example 2 and Production Example 3 were subjected to foam stability test after 5 minutes based on JIS K3362.
As a result, the dye ink (Cyan, Magenta, and Yellow) of Production Example 2 had a foam stability of about 30 mm or more after 5 minutes. On the other hand, all of the dye inks (Cyan, Magenta, and Yellow) of Production Example 3 had a foam stability of 10 mm or less after 5 minutes.

<Evaluation of ease of empty discharge flow>
About the combination of the dye ink of Production Example 2 and Production Example 4 and the pigment ink of Production Example 1, using the above-described inkjet printer (manufactured by Ricoh Co., Ltd., IPSiO G707), idle ejection (used to maintain stable ink ejection) Then, after the dirty head surface was wiped off with a blade, an operation of discharging the dirt mixed in the nozzle was performed.
In the case of the combination of the dye ink of Production Example 2 and the pigment ink of Production Example 1, only a small amount of pigment ink remained.
On the other hand, in the case of the combination of the dye ink of Production Example 4 and the pigment ink of Production Example 1, the ink flow was poor and the mass of the pigment ink was large at the idle discharge receptacle. In addition, as in Production Example 4, an ink having a large surface tension has a slow image drying and is likely to cause feathering on plain paper.

  The recording ink of the present invention is used for ink jet recording in which the dye ink and the highly viscous pigment ink are appropriately exchanged with the same head, and is clogged by mixing the dye ink and the highly viscous pigment ink. It is difficult to cause clotting, and ink can be smoothly supplied to the sub tank by electrode detection, and can be suitably used for an ink cartridge, an ink recorded material, an ink jet recording apparatus, and an ink jet recording method.

FIG. 1 is a graph showing a titration curve in the magenta pigment ink of the present invention. FIG. 2 is a graph showing a titration curve in the yellow pigment ink of the present invention. FIG. 3 is a graph showing the relationship between the titer and pH. FIG. 4 is a diagram showing an example of the ink cartridge of the present invention. FIG. 5 is a view including the case (exterior) of the ink cartridge of FIG. FIG. 6 is a schematic explanatory view showing an example of the ink jet recording apparatus of the present invention. FIG. 7 is a schematic explanatory view showing an example of the internal structure of the ink jet recording apparatus of FIG. FIG. 8 is a schematic enlarged view showing an example of the ink jet head of the present invention. FIG. 9 is a schematic view showing a nozzle row of the inkjet head of the present invention. FIG. 10 is an exploded perspective view of the liquid supply device in the ink jet recording apparatus of the present invention. 11 is an enlarged exploded perspective view of FIG. FIG. 12 is a schematic side view of the sub tank. 13A and 13B are schematic cross-sectional views taken along line AA in FIG. FIG. 14 is a top view of the maintenance unit according to the inkjet printer of the present invention. FIG. 15 is a schematic explanatory diagram of a maintenance unit according to the ink jet printer of the present invention. FIG. 16 is a graph showing the particle size distribution when pigment ink is added to dye ink in Examples.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Apparatus main body 2 Paper feed tray 3 Paper discharge tray 6 Ink cartridge loading part 7 Operation part 8 Front cover 10 Ink cartridge 11 Guide rod 12 Stay 13 Carriage 14 Recording head 15 Sub tank 16 Supply tube 22 Paper 23 Paper feed roller 24 Separation pad 25 Guide 31 Conveying belt 32 Counter roller 33 Conveying guide 34 Holding member 36 Charging roller 37 Conveying roller 38 Tension roller 41 Ink bag 42 Ink inlet 43 Ink outlet 44 Cartridge exterior 71 Maintenance recovery mechanism (subsystem)
DESCRIPTION OF SYMBOLS 100 Ink storage part 101 Case main body 102 Film-like member 103 Spring (spring)
113 connecting member 121 air flow path 126 accumulating part 131 atmosphere release hole 132 atmosphere release valve mechanism 133 holder 134 valve seat 135 ball 136 spring

Claims (22)

  Used for ink jet recording in which the dye ink and the pigment ink are exchanged with the same head, and the difference (pHA-pHB) between the pH (pHA) of the dye ink and the pH (pHB) of the pigment ink is -1 to 2. And the surface tension of the dye ink at 25 ° C. is 40 mN / m or less.   The recording ink according to claim 1, wherein the pH (pHA) of the dye ink is higher than the pH (pHB) of the pigment ink.   The recording ink according to claim 1, wherein the pigment ink has a pH buffering property in any of pH 6-9.   4. The recording ink according to claim 1, wherein the pigment ink and the dye ink have an ink viscosity at 25 ° C. of 5 mPa · s or more.   The pigment ink contains at least water, a pigment, a wetting agent, one of a polyol compound having 8 to 11 carbon atoms and a glycol ether compound, and a surfactant, and has a viscosity at 25 ° C. of 5 mPa · s or more, The recording ink according to claim 1, wherein the surface tension at 25 ° C. is 40 mN / m or less.   6. The recording according to claim 5, wherein the pigment is at least one selected from polymer fine particles containing at least one of a water-insoluble colorant and a poorly water-soluble colorant, and carbon black having at least one hydrophilic group on the surface. For ink.   The recording ink according to any one of claims 1 to 6, wherein the stability of the foam after 5 minutes based on JIS K3362 of the dye ink is less than 30 mm.   The dye ink contains at least water, a dye, a wetting agent, any one of a polyol compound having 8 to 11 carbon atoms and a glycol ether compound, an antifoaming agent, and a surfactant, and has a viscosity at 25 ° C. of 5 mPa · The recording ink according to claim 1, wherein the recording ink has a surface tension at 25 ° C. of 40 mN / m or less.   The recording ink according to claim 8, wherein the content of the wetting agent in the dye ink is 35 to 50% by mass.   The recording ink according to claim 8, wherein the content of the dye in the dye ink is 4% by mass or more.   The recording ink according to claim 8, wherein the antifoaming agent is a silicone-based antifoaming agent.   The recording ink according to claim 11, wherein the silicone-based antifoaming agent is one of a self-emulsifying silicone-based antifoaming agent and an emulsion-type silicone-based antifoaming agent.   An ink cartridge comprising the recording ink according to claim 1 contained in a container.   13. A dye ink with at least ink flying means for applying a stimulus to the recording ink according to claim 1 and causing the recording ink to fly to form an image, and the same head in the ink flying means. And an ink jet recording apparatus, wherein the pigment ink is used interchangeably.   The inkjet recording apparatus according to claim 14, wherein the stimulus is at least one selected from heat, pressure, vibration, and light.   The ink jet according to any one of claims 14 to 15, wherein the ink flying means includes a head having a plurality of nozzle rows, and a sub tank for storing the liquid supplied from the liquid storage tank and supplying the liquid to the head. Recording device.   The sub tank has a negative pressure generating means for generating a negative pressure in the sub tank, an air opening means for opening the inside of the sub tank to the atmosphere, and a detecting means for detecting the presence or absence of ink by a difference in electric resistance. The ink jet recording apparatus according to claim 16.   The ink jet recording apparatus according to claim 14, further comprising a scraping unit that scrapes off the ink fixed to the empty ejection receiver.   The ink jet recording apparatus according to claim 18, wherein the scraping means is one of a wiper and a cutter.   13. The method includes at least an ink flying step of applying a stimulus to the recording ink according to claim 1 and flying the recording ink to form an image. An ink jet recording method, wherein the pigment ink is used after being exchanged.   21. The ink jet recording method according to claim 20, wherein the stimulus is at least one selected from heat, pressure, vibration, and light. An ink recorded matter comprising an image formed using the recording ink according to any one of claims 1 to 12 on a recording medium.

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