JP2006299250A - Ink-jet printing ink, ink-jet printing method and ink-jet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink-jet printing ink causing no curls even if much ink is jetted on regular paper or the like in a short time, and also compatible with high-precision image printing while maintaining at high levels good responsiveness and stickproofness in jetting at high drive frequency. <P>SOLUTION: The ink-jet printing ink comprises water, a coloring material and a surfactant, wherein the content of the surfactant is 0.6-5 mass%. This ink also contains a block compound of formula (I): HO-(EO)<SB>a</SB>-(PO)<SB>b</SB>-(EO)<SB>c</SB>-H (wherein, EO denotes ethylene oxide; PO denotes propylene oxide; a, b and c meet the relationships: a≥0, 2≤b≤12, c≥0 and 1≤(a+c)≤60; and the proportion of EO in one molecule is 20-80 mass%). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an inkjet recording ink, an inkjet recording method and an inkjet recording apparatus using the same. More specifically, it is suitable for an ink jet recording method, and even when a large amount of water-based ink is applied to a cellulose-containing recording medium, the curling of the recording medium does not become a problem, and good responsiveness and recording at the time of discharging at a high driving frequency. The present invention relates to an ink for ink jet recording (hereinafter, abbreviated as “ink”) that gives good adhesion resistance of a head.

  The ink jet recording method is a method in which droplets of ink are ejected and attached to a recording medium such as paper, and various methods are known. Among them, an ejection system that uses an electrothermal converter as ejection energy supply means and ejects liquid droplets by applying bubbles to the ink by applying thermal energy to the ink is called a thermal system. According to this method, high-density multi-nozzle recording heads can be easily realized, and high-resolution and high-quality images can be recorded at high speed (see, for example, Patent Documents 1 to 3).

  In recent years, the size of ink droplets ejected from a single nozzle has been reduced in order to cope with extremely high-quality ink jet recording images at the silver salt photography level. At present, an ink jet printer having an ink droplet amount of about 5 pl (picoliter) or less is commercially available. Further, regarding the recording speed, further higher speed has been demanded. As the recording speed increases, there is an urgent need for inks to cope with higher driving frequencies and to improve the so-called fixing resistance that can effectively suppress the occurrence of ink sticking around the recording head. Yes.

  The ink used for ink jet recording is mainly composed of water, which is a medium for dissolving or dispersing the coloring material, and is water-soluble such as glycol for the purpose of preventing drying and improving the anti-sticking property of the recording head. In general, a high-boiling-point solvent is contained. When such a recording medium is used to record on a recording medium containing cellulose typified by plain paper, trace coated paper, base-absorbing coated paper, etc., the so-called curl is warped. A phenomenon may occur. For example, when a large amount of ink is applied in a short time to a region having a certain area or more, the recording medium warps and a curling phenomenon occurs. The occurrence of the curl phenomenon has not been a significant problem in the case of character center recording, which has been the mainstream in the past, because the amount of ink shot is small. However, in recent years, when recording an Internet home page or a photographic image, which has been widely used, it is necessary to print a large amount of ink on plain paper or the like, so the occurrence of the curling phenomenon is solved. It is one of the big issues that should be done.

  To solve these problems, water-based ink compositions containing various anti-curl materials have been proposed (see, for example, Patent Documents 4 and 5). In the ink using such a substance, a certain degree of effect is recognized with respect to curling resistance (meaning that an effect of suppressing curling is recognized). However, further improvement is desired for the compatibility between the responsiveness and sticking resistance at the time of high drive frequency ejection, which is a problem with the increase in recording speed, and the above-described curl resistance.

  On the other hand, there is a proposal for an ink containing a block compound having an ethylene oxide part and a propylene oxide part in its structure (referred to as a block compound in the present invention because of its low molecular weight to be called a block copolymer). (For example, refer to Patent Documents 6 and 7). However, even in the inks described in these conventional examples, it is hoped that the above technical problem of coexistence of responsiveness and sticking resistance at the time of high driving frequency ejection and curling resistance will be overcome at a higher level. It is rare.

Japanese Patent Publication No. 61-59911 Japanese Patent Publication No. 61-59912 Japanese Examined Patent Publication No. 61-59914 JP-A-6-157955 Japanese Patent Laid-Open No. 11-12520 Japanese Patent Publication No. 3-43313 Japanese Patent No. 2894202

  Accordingly, an object of the present invention is to cause a curl problem even when a large amount of ink is shot in a short time in an area of a certain area or more when recording with a water-based ink on a recording medium containing cellulose. It is an object of the present invention to provide an ink for ink jet recording. At the same time, to provide ink for ink jet recording that can cope with high-definition image recording while maintaining good responsiveness at the time of high drive frequency ejection and high resistance of the recording head. It is in.

  Another object of the present invention is to provide an ink jet recording method capable of stably forming a high-quality image. Furthermore, another object of the present invention is to provide an ink jet recording apparatus capable of realizing the above ink jet recording method.

［式（Ｉ）中、ＥＯはエチレンオキサイドを示し、ＰＯはプロピレンオキサイドを示し、ａ、ｂ及びｃは、ａ≧０、２≦ｂ≦１２、ｃ≧０、１≦ａ＋ｃ≦６０、を満足し、且つ、１分子中のＥＯ部の比率が質量基準で２０％以上８０％以下である。］ The above object is achieved by the present invention described below. That is, the present invention provides an inkjet recording ink comprising at least water, a colorant, and a surfactant, and the content of the surfactant in the ink is 0.6% by mass or more and 5% by mass or less. The ink further comprises a block compound represented by the following formula (I) in the ink.

[In the formula (I), EO represents ethylene oxide, PO represents propylene oxide, and a, b and c satisfy a ≧ 0, 2 ≦ b ≦ 12, c ≧ 0, 1 ≦ a + c ≦ 60. In addition, the ratio of the EO part in one molecule is 20% or more and 80% or less on a mass basis. ]

  As a preferred form of the ink according to the present invention, when the surfactant is a nonionic surfactant, the effect of the invention is more remarkable when it is for thermal ink jet.

Further, the present invention provides an ink jet recording method comprising a step of recording by applying ink to a cellulose-containing recording medium using an ink jet recording head, wherein the recording area of the recording medium is 15 cm ² or more, The amount of ink applied to the recording medium is 0.03 mg / cm ² or more and 30 mg / cm ² or less,
An ink jet recording method using the ink as an ink to be applied to the recording medium.

  According to another aspect of the invention, there is provided an ink jet recording apparatus comprising: an ink containing portion that contains the ink; and an ink jet recording head that discharges the ink.

  In the thermal ink jet recording system, ink is foamed by heat energy from a heater, and the ink is ejected by the pressure. For this reason, the ink is exposed to a high temperature and a high pressure at the time of foaming, and the amount due to the ink constituent material is slightly generated at each foaming although the amount is not certain. Since these deposits are sparingly soluble in water, they cause burns on the heater, and further cause poor foaming and a decrease in discharge amount, thereby shortening the life of the head. When the ink having the configuration according to the present invention is used, such a phenomenon can also be suppressed.

  According to the present invention, when used in inkjet recording, a water-based ink that does not cause curling even when a large amount of water-based ink is applied to a recording medium containing cellulose is provided. At the same time, the ink can cope with high-definition image recording while maintaining good responsiveness when ejecting at a high driving frequency and anti-sticking property of the recording head at a high level. Regarding the responsiveness at the time of high-frequency ejection, the effect of the present invention is particularly remarkable when used for thermal ink jet recording.

  Hereinafter, the present invention will be described in more detail with reference to preferred embodiments. In order to solve the technical problem against the future technical trend as described above, the present inventors have developed a basic characteristic as an ink for ink jet recording, specifically, a large amount of ink for a recording medium containing cellulose. Even when the recording medium is applied, the curling of the recording medium does not become a problem, and the high responsiveness at the time of discharging at a high driving frequency (specifically, a frequency exceeding 10 kHz) and the anti-sticking property of the recording head are high. In order to develop an inkjet recording printer that can handle high-definition image recording while maintaining the same level, intensive studies were conducted. As a result, it has been found that an ink having a composition containing a compound having a specific property can achieve the above object at an extremely high level, and has led to the present invention. Here, an overview of each problem to be solved by the present invention will be described.

1. Curling resistance When a large amount of aqueous ink is applied to a recording medium containing cellulose typified by plain paper, a so-called curling phenomenon occurs in which the recording medium is warped. When a strong curl phenomenon occurs, the paper may be rolled into a cylindrical shape in some cases.

  The mechanism of the curl phenomenon is thought to be due to the fact that water evaporates in a state where tension is applied in a certain direction and a hydrogen bond is formed between celluloses in the process of drying the paper in the papermaking stage. When water-based ink adheres to the paper in this state, the hydrogen bond between celluloses is broken by water and the bonding part is replaced by water, but when the water evaporates, hydrogen bonds between celluloses are formed again. Since no tension is applied when hydrogen bonds are re-formed, the ink adhering surface side of the paper contracts, and as a result, curl is considered to occur.

This phenomenon has not attracted attention because the amount of ink applied is relatively small in the conventional recording in which the image to be formed is centered on characters. However, in recent years when the frequency of printing of graphics with a large amount of ink applied has increased, it has become a major problem, and a marked improvement in curling resistance is required in image formation. In particular, on a recording medium such as plain paper containing cellulose, the recording area is 15 cm ² or more, and the amount of water-based ink applied to the recording surface is 0.03 mg / cm ² or more and 30 mg / cm ² or less. When recording, curling is remarkable. That is, the present invention can exert a particularly remarkable effect when ink jet recording is performed under such conditions. When the water-based ink shot amount is 0.1 mg / cm ² or more and 20 mg / cm ² or less, the effect of the present invention becomes more remarkable.

2. Frequency response In the on-demand ink jet system, when trying to eject continuously at a high drive frequency, depending on the physical and chemical properties of the ink, the ink may not be refilled in time, and before it is refilled. The next discharge may start. As a result, a discharge failure occurs or the discharge amount is extremely reduced. Moreover, this phenomenon becomes more remarkable as the droplets to be ejected are smaller. Therefore, in an ink jet printer that is developed to cope with an extremely high-quality ink jet recording image at a silver salt photograph level and has an ink droplet amount ejected from a single nozzle of about 5 pl (picoliter) or less. Especially problematic.

3. Sticking resistance (nozzle clogging resistance)
A problem caused by water evaporation of ink generated at the nozzle tip is nozzle clogging. Such a problem often occurs in the following cases. For example, when the printer is left unused for a period of time and the ink tank and the print head are integrated, the print head itself is left detached from the printer. Alternatively, in a form in which the ink tank and the print head can be separated, the ink tank is left in a state of being removed from the printer. This problem is caused by sticking of the coloring material generated at the nozzle tip due to evaporation of moisture in the ink.

  As a result of intensive investigations from the viewpoint of the composition of the ink, the inventors of the present invention have found that an ink containing a compound having a specific property in a specific composition achieves the above purpose at a very high level. I have found that I can achieve it. The ink according to the present invention will be described below.

  The ink according to the present invention includes water, a coloring material, a surfactant of 0.6% by mass to 5% by mass, and, in addition to these, a portion made of ethylene oxide (ethylenelen oxide unit) in the structure. And a compound having a portion made of propylene oxide (propylene oxide unit). First, these components will be described.

［式（Ｉ）中、ＥＯはエチレンオキサイドを示し、ＰＯはプロピレンオキサイドを示し、ａ、ｂ及びｃは、ａ≧０、２≦ｂ≦１２、ｃ≧０、１≦ａ＋ｃ≦６０、を満足し、且つ、１分子中のＥＯ部の比率が質量基準で２０％以上８０％以下である。］ The ink according to the present invention must contain a compound represented by the following formula (I) that characterizes the present invention. The compound is a compound having the following structure formed by adding ethylenelen oxide units composed of 1 to 60 EO in total and propylene oxide units composed of 2 to 12 PO in a block form.

[In the formula (I), EO represents ethylene oxide, PO represents propylene oxide, and a, b and c satisfy a ≧ 0, 2 ≦ b ≦ 12, c ≧ 0, 1 ≦ a + c ≦ 60. In addition, the ratio of the EO part in one molecule is 20% or more and 80% or less on a mass basis. ]

Here, EO constituting the ethylene oxide unit and PO constituting the propylene oxide unit are organic groups having the following structure.

  The block compound having the structure as mentioned above can be synthesized by a conventional method. Examples of the block compound that can be used in the present invention include compounds (1) to (14) in which a, b, and c in the above formula (I) have values as shown in Table 1, respectively. Of course, the present invention is not limited to these. In Table 1, the ratio of the EO part in each block compound is shown on a mass basis. In the present invention, it is preferable that both a and c are not 0.

  The content of the compound represented by the formula (I) used in the present invention as listed above in the ink is preferably 0.5% by mass or more and 40% by mass or less with respect to the total mass of the ink. The content in the ink is more preferably 1% by mass to 35% by mass, and still more preferably 1.5% by mass to 30% by mass.

  As described above, the present invention is characterized in that a compound having a propylene oxide unit having 2 to 12 PO addition numbers on the molecular structure is used as an ink component. Block compounds having a propylene oxide unit on the molecular structure are also used in conventional ink jet inks. However, in this case, any of them is used as a surfactant and generally has a PO addition number of about 15 to 65. Accordingly, the block compound used in the present invention in which the number of PO addition of the propylene oxide unit is 2 to 12 has not been particularly noticed as an ink application. That is, according to the study by the present inventors, when the number of PO addition of the propylene oxide unit exceeds 12, although the occurrence of curling can be suppressed to some extent, the viscosity of the ink increases, and the ink component at the nozzle tip portion increases. It is inferior to the ejection failure and high-frequency ejection responsiveness due to partial evaporation.

(Aqueous medium)
The ink according to the present invention contains water as an essential component. The content of water in the ink is preferably 30% by mass or more and preferably 95% by mass or less with respect to the total mass of the ink. In many cases, an aqueous medium in which water and a water-soluble solvent are used in combination is used. Examples of the constituent material used in combination with water include, for example, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, n-pentanol and the like. To 5 alkyl alcohols;
Amides such as dimethylformamide and dimethylacetamide;
Ketones or ketoalcohols such as acetone and diacetone alcohol;
Ethers such as tetrahydrofuran and dioxane;
Oxyethylene or oxypropylene polymers such as diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol, polypropylene glycol;
Alkylene glycols in which the alkylene group contains 2 to 6 carbon atoms, such as ethylene glycol, propylene glycol, trimethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-pexanediol;
Triols such as 1,2,6-hexanetriol, glycerin, trimethylolpropane;
Lower alkyl ethers of glycols such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol monomethyl (or ethyl) ether, triethylene glycol monomethyl (or ethyl, butyl) ether;
Lower dialkyl ethers of polyhydric alcohols such as triethylene glycol dimethyl (or ethyl) ether, tetraethylene glycol dimethyl (or ethyl) ether;
Alkanolamines such as monoethanolamine, diethanolamine, triethanolamine;
Examples include sulfolane, N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, urea, ethylene urea, bishydroxyethyl sulfone, and diglycerin.

  Among these, it is preferable to use ethylene glycol, polyethylene glycol (average molecular weight of 200 or more and 1,000 or less), glycerin, 1,2,6-hexanetriol, ethylene urea, or trimethylolpropane, and ethylene urea is most preferable. It is. In the ink according to the present invention, the type and content of the water-soluble solvent used in combination with water are not particularly limited, but are preferably 3% by mass or more and 60% by mass or less, for example, based on the total amount of the ink. It is preferable that

(Surfactant)
In order to obtain a more balanced ejection stability, the ink according to the present invention contains 0.6% by mass or more and 5% by mass or less of a surfactant in addition to the components described above. Is essential. In the present invention, it is preferable to include a nonionic surfactant among the surfactants. Furthermore, among the nonionic surfactants, polyoxyethylene alkyl ethers and ethylene oxide adducts of acetylene glycol are particularly preferable. These nonionic surfactants have an HLB value (Hydrophile-Lipophile Balance) of 10 or more. The content of these surfactants in the ink needs to be 0.6% by mass or more and 5% by mass or less, preferably 0.7% by mass or more and 4% by mass or less, more preferably 0.8% by mass. % To 3% by mass.

(Other additives)
In addition to the above-described components, the ink according to the present invention may have, as necessary, a viscosity modifier, an antifoaming agent, an antiseptic, and an antifungal agent in order to obtain an ink having a desired physical property value. An agent, an antioxidant and the like can be added. The additive is preferably selected so that the surface tension of the ink is 25 mN / m or more, preferably 28 mN / m or more.

(Color material)
Next, dyes and pigments can be used as the color material contained in the ink according to the present invention. The content of the coloring material in the ink is not limited to this range, but is 0.1% by mass or more and 15% by mass or less, preferably 0.2% by mass or more and 12% by mass or less with respect to the total amount of the ink. More preferably, it is 0.3 mass% or more and 10 mass% or less.

  Almost all of the water-soluble acid dyes, direct dyes, basic dyes, and reactive dyes described in the COLOR INDEX can be used as the dye used in the ink. Even those not described in the color index can be used as long as they are water-soluble dyes.

  Specific examples of the dye used in the present invention are listed below. Examples of the dye used for the yellow ink include C.I. I. Direct Yellow 173, 142, 144, 86, 132 and C.I. I. Acid yellow 23, 17 and the like. Examples of the dye used in the magenta ink include C.I. I. Acid Red 92, 289, 35, 37, 52 and the like. Examples of the dye used for the cyan ink include C.I. I. Acid Blue 9, 7, 103, 1, 90, C.I. I. Direct blue 86, 87, 199 etc. are mentioned. Examples of the dye used for the black ink include C.I. I. Food Black 2, C.I. I. Direct black 52, 154, 195 etc. are mentioned. However, the present invention is not limited to these.

As the coloring material contained in the ink according to the present invention, the following pigments can be used. Carbon black is preferably used as the pigment used in the black ink. For example, carbon black pigments such as furnace black, lamp black, acetylene black, channel black, etc., primary particle size of 15 nm to 40 nm, specific surface area by BET method of 50 m ² / g to 300 m ² / g, DBP oil absorption Is preferably 40 ml / 100 g or more and 150 ml / 100 g or less, and has a volatile content of 0.5 mass% or more and 10 mass% or less.

As the pigment used in the color ink, an organic pigment is preferably used. Specifically, insoluble azo pigments such as toluidine red, toluidine maroon, Hansa yellow, benzidine yellow, pyrazolone red;
Water-soluble azo pigments such as ritole red, helio bordeaux, pigment scarlet, permanent red 2B;
Derivatives from vat dyes such as alizarin, indanthrone, thioindigo maroon;
Phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green;
Quinacridone pigments such as quinacridone red and quinacridone magenta;
Perylene pigments such as perylene red and perylene scarlet;
Isoindolinone pigments such as isoindolinone yellow and isoindolinone orange;
Imidazolone pigments such as benzimidazolone yellow, benzimidazolone orange, and benzimidazolone red;
Pyranthrone pigments such as pyranthrone red and pyranthrone orange indigo pigments;
Condensed azo pigments;
Thioindigo pigments;
Diketopyrrolopyrrole pigments;
Examples include pigments such as flavanthron yellow, acylamide yellow, quinophthalone yellow, nickel azo yellow, copper azomethine yellow, perinone orange, anthrone orange, dianthraquinonyl red, and dioxazine violet.

Further, when the organic pigment is represented by a color index (CI) number, C.I. I. Pigment Yellow 12, 13, 14, 17, 20, 24, 55, 74, 83, 86, 93, 97, 98, 109, 110, 117, 120, 125, 128, 137, 138, 139, 147, 148, 150, 151, 153, 154, 155, 166, 168, 180, 185;
C. I. Pigment orange 16, 36, 43, 51, 55, 59, 61, 71;
C. I. Pigment Red 9, 48, 49, 52, 53, 57, 97, 122, 123, 149, 168, 175, 176, 177, 180, 192, 202, 209, 215, 216, 217, 220, 223, 224, 226, 227, 228, 238, 240, 254, 255, 272;
C. I. Pigment violet 19, 23, 29, 30, 37, 40, 50;
C. I. Pigment blue 15, 15: 1, 15: 3, 15: 4, 15: 6, 22, 60, 64;
C. I. Pigment green 7, 36;
C. I. Examples thereof include CI Pigment Brown 23, 25, 26, and the like.

Although pigments other than those described above can be used, in particular, among these pigments, C.I. I. Pigment Yellow 13, 17, 55, 74, 93, 97, 98, 110, 128, 139, 147, 150, 151, 154, 155, 180, 185;
C. I. Pigment red 122, 202, 209;
C. I. Pigment Blue 15: 3 and 15: 4 are more preferable.

  When the pigment is used as the coloring material, the average particle diameter of the pigment is preferably in the range of 50 nm to 200 nm. As a method for measuring the average particle size, ELS-8000 (manufactured by Otsuka Electronics Co., Ltd.), Microtrac UPA 150 (manufactured by Nikkiso Co., Ltd.), etc. using laser light scattering can be used.

(Dispersant)
The dispersant for dispersing the pigment is not particularly limited as long as it is water-soluble, but is a block copolymer or a random copolymer composed of two or more monomers (at least one is a hydrophilic monomer). , Graft copolymers, or salts thereof are preferred. Specific monomers include the following. For example, styrene, styrene derivatives, vinyl naphthalene, vinyl naphthalene derivatives, aliphatic alcohol esters of α, β-ethylenically unsaturated carboxylic acids, acrylic acid, acrylic acid derivatives, maleic acid, maleic acid derivatives, itaconic acid, itaconic acid Examples thereof include derivatives, fumaric acid, fumaric acid derivatives, vinyl acetate, vinyl pyrrolidone, acrylamide, and derivatives thereof. Among them, a dispersant that is particularly suitable for the ink of the present invention is a block copolymer composed of two or more (at least one hydrophilic monomer) monomers selected from the monomers listed above. is there. In particular, when the above block copolymer is used in the present invention when driven at a high drive frequency, for example, 10 kHz or more, with a head using thermal energy, the effect of improving the discharge property becomes more remarkable.

  The preferable amount of the dispersant in the ink is 0.5% by mass or more and 10% by mass or less, preferably 0.8% by mass or more and 8% by mass or less, more preferably 1% by mass or more and 6% by mass with respect to the total amount of the ink. The range is as follows. If the dispersant content is higher than this range, it may be difficult to maintain the desired ink viscosity.

  The ink according to the present invention provides an excellent effect when used in ink jet recording. The ink jet recording apparatus in this case will be described using an ink jet printer as a specific example. FIG. 1 is a schematic perspective view showing a main part of an example of a liquid discharge head as a liquid discharge head of a discharge method that communicates bubbles with the atmosphere during discharge and an ink jet printer that is a liquid discharge apparatus using the head.

  In FIG. 1, the inkjet printer includes a conveyance device 1030 that intermittently conveys a paper 1028 as a recording medium provided in a longitudinal direction in a casing 1008 in a direction indicated by an arrow P, and conveyance of the paper 1028 by the conveyance device 1030. The recording unit 1010 is configured to reciprocate substantially in parallel with the guide shaft 1014 in an arrow S direction substantially orthogonal to the direction P, and a movement driving unit 1006 as a driving unit that reciprocates the recording unit 1010. ing.

  The conveying device 1030 includes a pair of roller units 1022a and 1022b that are arranged to face each other substantially in parallel, a pair of roller units 1024a and 1024b, and a drive unit 1020 for driving each of these roller units. Yes. With this configuration, when the driving unit 1020 of the transport device 1030 is activated, the paper 1028 is sandwiched between the roller units 1022a and 1022b and the roller units 1024a and 1024b, and is intermittently fed in the direction of the arrow P. It will be transported. The moving drive unit 1006 is disposed substantially parallel to the pulley 1026a disposed on the rotation shaft opposed to the pulley 1026b with a predetermined interval and the belt 1016 wound around the pulley 1026b, the roller unit 1022a, and the roller unit 1022b. The motor 1018 is configured to drive the belt 1016 coupled to the carriage member 1010a of the portion 1010 in the forward direction and the reverse direction.

  When the motor 1018 is activated and the belt 1016 rotates in the arrow R direction, the carriage member 1010a of the recording unit 1010 is moved in the arrow S direction by a predetermined movement amount. When the motor 1018 is activated and the belt 1016 rotates in the direction opposite to the arrow R direction shown in the drawing, the carriage member 1010a of the recording unit 1010 moves in a predetermined direction in the direction opposite to the arrow S direction. It will be moved by the amount. Further, a recovery unit 1026 for performing an ejection recovery process of the recording unit 1010 is opposed to the ink ejection port array of the recording unit 1010 at one end of the movement driving unit 1006 at a position that becomes the home position of the carriage member 1010a. Is provided.

  The recording unit 1010 is detachably attached to the carriage member 1010a for each color, for example, yellow, magenta, cyan, and black, for each of the ink jet cartridges (hereinafter, simply referred to as cartridges) 1012Y, 1012M, 1012C, and 1012B. Prepared for.

  FIG. 2 shows an example of an ink jet cartridge that can be mounted on the above-described ink jet recording apparatus. The cartridge 1012 in the illustrated example is of a serial type, and the main part is constituted by the ink jet recording head 100 and an ink tank 1001 for containing ink.

  The ink jet recording head 100 is formed with a number of ejection ports 832 for ejecting ink, and the ink is supplied from the ink tank 1001 through an ink supply passage (not shown) to a common liquid chamber (not shown) of the liquid ejection head 100. ). A cartridge 1012 shown in FIG. 2 is formed by integrally forming an ink jet recording head 100 and an ink tank 1001 so that liquid can be supplied into the ink tank 1001 as necessary. A structure in which an ink tank 1001 is connected to 100 in an exchangeable manner may be employed. An ink jet cartridge equipped with an ink jet recording head is a recording unit.

  Next, the present invention will be described more specifically with reference to examples and comparative examples. In the text, “%” is based on mass unless otherwise specified. The remainder means the remainder obtained by subtracting each component from 100% as a whole.

<Example 1>
(Preparation of pigment dispersion 1)
First, using benzyl methacrylate and methacrylic acid as raw materials, an AB type block polymer having an acid value of 250 and a weight average molecular weight of 3,000 is prepared by a conventional method, further neutralized with an aqueous potassium hydroxide solution, and diluted with ion-exchanged water. A homogeneous 50% aqueous polymer solution was prepared. 180 g of the obtained aqueous polymer solution, C.I. I. 100 g of CI Pigment Blue 15: 3 and 220 g of ion-exchanged water were mixed and mechanically stirred for 0.5 hour. The mixture was then processed using a microfluidizer by passing the mixture through the interaction chamber five times under a liquid pressure of about 10,000 psi (about 70 MPa). Further, the dispersion obtained above was centrifuged (12,000 rpm, 20 minutes) to remove the non-dispersion containing coarse particles, thereby preparing a cyan pigment dispersion 1. The obtained pigment dispersion 1 had a pigment concentration of 10% and a dispersant concentration of 10%.

(Preparation of ink 1)
The ink 1 was prepared using the cyan pigment dispersion 1 obtained above, and the following components were added to this to obtain a predetermined concentration. After these components were sufficiently mixed and stirred, the pore size was 2.5 μm. The solution was filtered under pressure with a microfilter (manufactured by Fuji Film). As a result, an ink 1 having a pigment concentration of 2% and a dispersant concentration of 2% was obtained. The compound (1) used in the following composition has the following structure, and the ratio of its EO part is 57% on a mass basis. In the following ink composition, “remainder” means that the concentration of each component constituting the ink is adjusted with ion-exchanged water so that the total concentration becomes 100%. In the following composition, “EO addition” means addition of ethylene oxide. “Remainder” and “EO addition” are the same in the preparation of other inks.

・ Pigment dispersion 1 20%
・ Compound (1) 16%
EO addition product of acetylene glycol (trade name: acetylenol EH; manufactured by Kawaken Fine Chemicals, nonionic surfactant with HLB of 10 or more) 0.5%
・ Polyoxyethylene cetyl ether (EO addition number = 30, HLB = 19.5, nonionic surfactant) 0.5%
・ Ion exchange water balance

<Example 2>
(Preparation of pigment dispersion 2)
100 g of a polymer solution similar to that used in the preparation of Pigment Dispersion Liquid 1, C.I. I. 100 g of Pigment Red 122 and 300 g of ion-exchanged water were mixed and mechanically stirred for 0.5 hour. The mixture was then processed using a microfluidizer by passing the mixture through the interaction chamber five times under a liquid pressure of about 10,000 psi (about 70 MPa). Further, the dispersion obtained above was centrifuged (12,000 rpm, 20 minutes) to remove the non-dispersion containing coarse particles, thereby obtaining a magenta pigment dispersion 2. The obtained pigment dispersion 2 had a pigment concentration of 10% and a dispersant concentration of 5%.

(Preparation of ink 2)
The ink 2 was prepared by using the magenta pigment dispersion 2 described above, adding the following components to a predetermined concentration, mixing and stirring these components sufficiently, and then micropores with a pore size of 2.5 μm ( The solution was filtered under pressure using a Fujifilm Corporation. As a result, an ink 2 having a pigment concentration of 4% and a dispersant concentration of 2% was obtained. The compound (6) used in the following composition has the following structure, and the ratio of its EO part is 58% on a mass basis.

・ Pigment dispersion 2 40%
・ Compound (6) 12%
・ Polyethylene glycol (average molecular weight 300) 6%
・ Ethyleneurea 4%
-Acetylene glycol EO adduct (trade name: acetylenol EH; manufactured by Kawaken Fine Chemical) 0.6%
・ Ion exchange water balance

<Example 3>
(Preparation of pigment dispersion 3)
First, using benzyl acrylate and methacrylic acid as raw materials, an AB type block polymer having an acid value of 300 and a weight average molecular weight of 4,000 is prepared by a conventional method, further neutralized with an aqueous potassium hydroxide solution, and diluted with ion-exchanged water. A homogeneous 50% aqueous polymer solution was prepared. 110 g of the above polymer aqueous solution, C.I. I. 100 g of Pigment Yellow 128 and 290 g of ion-exchanged water were mixed and mechanically stirred for 0.5 hour. The mixture was then processed using a microfluidizer by passing the mixture through the interaction chamber five times under a liquid pressure of about 10,000 psi (about 70 MPa). Further, the pigment dispersion 3 obtained above was centrifuged (12,000 rpm, 20 minutes) to remove the non-dispersed material containing coarse particles, thereby preparing the pigment dispersion 3. The obtained pigment dispersion 3 had a pigment concentration of 10% and a dispersant concentration of 6%.

(Preparation of ink 3)
The ink 3 was prepared by using the yellow pigment dispersion 3 described above, adding the following components to a predetermined concentration, thoroughly mixing and stirring these components, and then microfilter (pore size 2.5 μm) The solution was filtered under pressure using a Fujifilm Corporation. As a result, an ink 3 having a pigment concentration of 5% and a dispersant concentration of 3% was obtained. The compound (8) used in the following composition has the following structure, and the ratio of its EO part is 58% on a mass basis.

・ Pigment dispersion 3 50%
・ Compound (8) 8%
・ 1,6-hexanediol 6%
・ Triethylene glycol 4%
-Acetylene glycol EO adduct (trade name: acetylenol EH; manufactured by Kawaken Fine Chemicals) 0.3%
・ Polyoxyethylene cetyl ether (EO addition number = 30, HLB = 19.5) 1.0%
・ Ion exchange water balance

<Example 4>
(Preparation of pigment dispersion 4)
First, using benzyl methacrylate, methacrylic acid and ethoxyethylene glycol methacrylate as raw materials, an ABC type block polymer having an acid value of 350 and a weight average molecular weight of 5,000 is prepared by a conventional method, and further neutralized with an aqueous potassium hydroxide solution. Diluted with exchange water to make a homogeneous 50% aqueous polymer solution. 60 g of the above polymer aqueous solution, 100 g of carbon black and 340 g of ion exchange water were mixed and mechanically stirred for 0.5 hour. The mixture was then processed using a microfluidizer by passing the mixture through the interaction chamber five times under a liquid pressure of about 10,000 psi (about 70 MPa). Further, the dispersion obtained above was centrifuged (12,000 rpm, 20 minutes) to remove the non-dispersion containing coarse particles, whereby a black pigment dispersion 4 was obtained. The obtained pigment dispersion 4 had a pigment concentration of 10% and a dispersant concentration of 3.5%.

(Preparation of ink 4)
The ink 4 was prepared by using the above black pigment dispersion 4 and adding the following components to a predetermined concentration, mixing and stirring these components sufficiently, and then microfilter (Fuji size) with a pore size of 2.5 μm. And filtered under pressure. As a result, an ink 4 having a pigment concentration of 3% and a dispersant concentration of 1.05% was obtained. The compound (10) used in the following composition has the following structure, and the ratio of its EO part is 59% on a mass basis.

・ Pigment dispersion 4 30%
・ Compound (10) 8%
・ Trimethylolpropane 6%
・ Polyethylene glycol (average molecular weight 200) 2%
Polyoxyethylene cetyl ether (EO addition number = 30, HLB = 19.5) 2%
・ Ion exchange water balance

<Example 5>
(Preparation of ink 5)
The following components were sufficiently mixed and stirred to prepare ink 5. The compound (14) in the following composition has the following structure, and the ratio of its EO part is 60% on a mass basis.

・ C. I. Direct Blue 199 3.5%
・ Compound (14) 4%
・ Diglycerin 6%
・ Ethyleneurea 8%
-Acetylene glycol EO adduct (trade name: acetylenol EH; manufactured by Kawaken Fine Chemicals) 1%
・ Ion exchange water balance

<Example 6>
(Preparation of ink 6)
The following components were sufficiently mixed and stirred to prepare ink 6. Compound (3) in the following composition has the following structure, and the ratio of its EO part is 72% on a mass basis.

・ C. I. Acid Red 289 3%
・ Compound (3) 15%
・ Ethyleneurea 4%
-Acetylene glycol EO adduct (trade name: acetylenol EH; manufactured by Kawaken Fine Chemicals) 1.2%
・ Ion exchange water balance

<Example 7>
(Preparation of ink 7)
The following components were sufficiently mixed and stirred to prepare ink 7. The compound (13) in the following composition has the following structure, and the ratio of its EO part is 80% on a mass basis.

・ C. I. Direct Yellow 132 3%
Compound (13) 3%
・ Bishydroxyethyl sulfone 9%
・ Polyethylene glycol (average molecular weight 300) 5%
-Acetylene glycol EO adduct (trade name: acetylenol EH; manufactured by Kawaken Fine Chemicals) 1.2%
・ Ion exchange water balance

<Example 8>
(Preparation of ink 8)
The following components were sufficiently mixed and stirred to prepare ink 8. The compound (4) in the following composition has the following structure, and the ratio of its EO part is 25% on a mass basis.

・ C. I. Food Black 2 2.5%
・ Compound (4) 25%
-Acetylene glycol EO adduct (trade name: acetylenol EH; manufactured by Kawaken Fine Chemicals) 1.0%
・ Ion exchange water balance

<Comparative Example 1>
(Preparation of ink 9)
The compound (1) used in Example 1 was replaced with diethylene glycol, and ink 9 was obtained in the same manner as in Example 1 with the following composition.
・ Pigment dispersion 1 20%
・ Diethylene glycol 16%
-Acetylene glycol EO adduct (trade name: acetylenol EH; manufactured by Kawaken Fine Chemical) 0.5%
・ Polyoxyethylene cetyl ether (EO addition number = 30, HLB = 19.5) 0.5%
・ Ion exchange water balance

<Comparative Example 2>
(Preparation of ink 10)
The content of the ethylene oxide adduct of acetylene glycol used in Example 2 was changed, and ink 10 was obtained as in Example 2 as the following composition.
・ Pigment dispersion 2 40%
・ Compound (6) 12%
・ Polyethylene glycol (average molecular weight 300) 6%
・ Ethyleneurea 4%
-Acetylene glycol EO adduct (trade name: acetylenol EH; manufactured by Kawaken Fine Chemical) 0.5%
・ Ion exchange water balance

<Comparative Example 3>
(Preparation of ink 11)
The content of the ethylene oxide adduct of acetylene glycol used in Example 2 was changed, and ink 11 was obtained as in Example 2 as the following composition.
・ Pigment dispersion 2 40%
・ Compound (6) 12%
・ Polyethylene glycol (average molecular weight 300) 6%
・ Ethyleneurea 4%
-Acetylene glycol EO adduct (trade name: acetylenol EH; manufactured by Kawaken Fine Chemicals) 5.5%
・ Ion exchange water balance

<Comparative example 4>
(Preparation of ink 12)
The compound (8) used in Example 3 was replaced with tetraethylene glycol, and ink 12 was obtained as in Example 1 with the following composition.
・ Pigment dispersion 3 50%
・ Tetraethylene glycol 8%
・ 1,6-hexanediol 6%
・ Triethylene glycol 4%
-Acetylene glycol EO adduct (trade name: acetylenol EH; manufactured by Kawaken Fine Chemicals) 0.3%
・ Polyoxyethylene cetyl ether (EO addition number = 30, HLB = 19.5) 1.0%
・ Ion exchange water balance

<Comparative Example 5>
(Preparation of ink 13)
The compound (13) used in Example 7 was replaced with the compound (15) having the structure shown below, and an ink 13 was obtained in the same manner as in Example 7 with the following composition. The ratio of the EO part of the compound (15) is 81% on a mass basis.

・ C. I. Direct Yellow 132 3%
・ Compound (15) 3%
・ Bishydroxyethyl sulfone 9%
・ Polyethylene glycol (average molecular weight 300) 5%
-Acetylene glycol EO adduct (trade name: acetylenol EH; manufactured by Kawaken Fine Chemicals) 1.2%
・ Ion exchange water balance

<Comparative Example 6>
(Preparation of ink 14)
The compound (1) used in Example 1 was replaced with the compound (16) having the structure shown below, and an ink 14 was obtained in the same manner as in Example 1 with the following composition. The ratio of the EO part of the compound (16) is 70% on a mass basis.

・ Pigment dispersion 1 20%
Compound (16) 16%
-Acetylene glycol EO adduct (trade name: acetylenol EH; manufactured by Kawaken Fine Chemical) 0.5%
・ Polyoxyethylene cetyl ether (EO addition number = 30, HLB = 19.5) 0.5%
・ Ion exchange water balance

<Comparative Example 7>
(Preparation of ink 15)
The compound (14) of Example 5 was replaced with the following compound (17), and ink 15 was obtained in the same manner as in Example 5 with the following composition. The ratio of the EO part of the compound (17) is 58% on a mass basis.

・ C. I. Direct Blue 199 3.5%
Compound (17) 4%
・ Diglycerin 6%
・ Ethyleneurea 8%
-Acetylene glycol EO adduct (trade name: acetylenol EH; manufactured by Kawaken Fine Chemicals) 1%
・ Ion exchange water balance

<Comparative Example 8>
(Preparation of ink 16)
The compound (14) of Example 5 was replaced with the compound (18) having the structure shown below, and an ink 16 was obtained in the same manner as in Example 5 as the following composition. The ratio of the EO part of the compound (18) is 6% on a mass basis.

・ C. I. Direct Blue 199 3.5%
Compound (18) 4%
・ Diglycerin 6%
・ Ethyleneurea 8%
-Acetylene glycol EO adduct (trade name: acetylenol EH; manufactured by Kawaken Fine Chemicals) 1%
・ Ion exchange water balance

<Comparative Example 9>
(Preparation of ink 17)
The compound (14) of Example 5 was replaced with the compound (19) having the structure shown below, and an ink 17 was obtained in the same manner as in Example 5 with the following composition. The ratio of the EO part of the compound (19) is 85% on a mass basis.

・ C. I. Direct Blue 199 3.5%
Compound (19) 4%
・ Diglycerin 6%
・ Ethyleneurea 8%
-Acetylene glycol EO adduct (trade name: acetylenol EH; manufactured by Kawaken Fine Chemicals) 1%
・ Ion exchange water balance

The structures of the compounds used in the comparative examples are summarized in Table 2 using the following formula (I).

<Evaluation>
The inks of Examples 1 to 8 (Inks 1 to 8) and Comparative Examples 1 to 9 (Inks 9 to 17) obtained above were evaluated as follows. FIG. 1 shows the ink jet recording apparatus used in the evaluation items (1), (2), and (3). The recording head used here had a recording density of 1,200 dpi, and the ejection volume per dot was 4 pl.

[Evaluation item]
(1) Frequency responsiveness Using a thermal Canon inkjet recording device, each ink is ejected at a drive frequency of 0.1 kHz, and the frequency is gradually increased, and the ejection shape is unstable with no main droplets present. The frequency was measured and judged at the point of time when a proper discharge occurred. Table 3 summarizes the evaluation results.
A: Over 10 kHz B: 5 kHz or more and 10 kHz or less C: Less than 5 kHz

(2) Sticking resistance The head containing each ink mounted on the recording apparatus was removed from the main body and left for 1 week in an environment of 35 ° C. and humidity 10%. Thereafter, a head was attached to the recording apparatus, and it was checked whether or not printing could be recovered by a normal recovery operation, and the sticking resistance of each ink was evaluated. The evaluation criteria are as follows. Table 3 summarizes the evaluation results.
A: It recovers by one main body recovery operation. B: It recovers by several main body recovery operations. C: It does not recover by main body recovery operation.

(3) Curling resistance Using the above recording apparatus, solid printing was performed on A4 size plain paper (SW-101, manufactured by Canon Inc.), leaving 2 cm above, below, left, and right of the paper. If recorded in this condition, the recording area of the recording material is a 431.8Cm ^2, ejection amount of the ink to the recording surface becomes 1.36 mg / cm ^2. The obtained recorded matter was left in an environment of 25 ° C. and 55% humidity. Then, the state after 1 hour and 10 days was observed and visually evaluated. The evaluation criteria are as follows. Table 3 summarizes the evaluation results.
A: It is almost flat B: The edge part is rising C: It is cylindrical

  From the results of the evaluations (1) to (3) in Table 3 above, it was confirmed that all of the inks 1 to 8 according to Examples 1 to 8 had good inkjet discharge suitability and curl resistance. It was. On the other hand, from the results of Comparative Examples 1 to 9, the amount of surfactant used in combination is outside the range, the number of additions of ethylene oxide and propylene oxide, and the mass ratio of the ethylene oxide part are within the scope of the present invention. It was confirmed that the ink containing the compound that is outside has a problem in the anti-sticking property and the response at the time of high-frequency ejection even when the anti-curl property is not sufficient or the curl property is good. .

It is a schematic perspective view which shows the principal part of an example of the inkjet printer which can mount a liquid discharge head. It is a schematic perspective view showing an example of an ink jet cartridge provided with a liquid discharge head.

Claims (9)

In an inkjet recording ink comprising at least water, a colorant, and a surfactant, the content of the surfactant in the ink is 0.6 mass% or more and 5 mass% or less, and the following formula (I An ink for ink jet recording, further comprising a block compound represented by

[In the formula (I), EO represents ethylene oxide, PO represents propylene oxide, and a, b and c satisfy a ≧ 0, 2 ≦ b ≦ 12, c ≧ 0, 1 ≦ a + c ≦ 60. In addition, the ratio of the EO part in one molecule is 20% or more and 80% or less on a mass basis. ]   The ink for inkjet recording according to claim 1, wherein the surfactant is a nonionic surfactant. In an inkjet recording method comprising a step of recording by applying ink to a cellulose-containing recording medium using an inkjet recording head, the recording area of the recording medium is 15 cm ² or more, and the ink onto the recording medium The applied amount is 0.03 mg / cm ² or more and 30 mg / cm ² or less,
The ink to be applied to the recording medium contains at least water, a coloring material, and a surfactant, the content of the surfactant in the ink is 0.6% by mass to 5% by mass, and the following formula An ink jet recording method comprising an ink further containing the block compound represented by (I).

[In the formula (I), EO represents ethylene oxide, PO represents propylene oxide, and a, b and c satisfy a ≧ 0, 2 ≦ b ≦ 12, c ≧ 0, 1 ≦ a + c ≦ 60. In addition, the ratio of the EO part in one molecule is 20% or more and 80% or less on a mass basis. ] The inkjet recording method according to claim 3, wherein the amount of ink applied to the recording medium is in the range of 0.1 mg / cm ^{2 to} 20 mg / cm ² .   The inkjet recording method according to claim 3 or 4, wherein the surfactant is a nonionic surfactant.   The ink jet recording method according to claim 3, wherein the recording medium containing cellulose is plain paper.   The ink jet recording method according to claim 3, wherein the ink jet recording head is a thermal ink jet head.   An ink jet recording apparatus comprising: an ink containing portion that contains the ink according to claim 1; and an ink jet recording head that discharges the ink. The ink jet recording apparatus according to claim 8, wherein the ink jet recording head is a thermal ink jet head.

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