JP5037261B2 - Ink set, ink media set, ink jet recording method and ink jet recording apparatus - Google Patents

Description

  The present invention relates to an ink set suitably used for various image recording by an ink jet recording method, an ink media set, an ink jet recording method, and an ink jet recording apparatus.

As a prior art document relating to an ink that defines an equilibrium moisture content, for example, Patent Document 1 discloses a part of a space formed between a print head and a cap that can be bonded to the front surface covering a nozzle on the front surface. In a method of filling a wetting liquid and thereby preventing clogging of the nozzles with ink, a colorless liquid mainly composed of water having a vapor pressure substantially equal to the vapor pressure of the ink is used as the wetting agent. Proposed.
Patent Document 2 includes a colorant aqueous solution as a main component and a wetting agent, and the wetting agent is one water-soluble organic solvent or a mixed system of two or more water-soluble organic solvents. Each ink in an ink set has an equilibrium water content of 30 parts by mass or less with respect to 100 parts by mass of a wetting agent under the temperature and humidity conditions of 25 ° C. and 60% RH.
Patent Document 3 includes a colorant, a wetting agent, a surfactant, and a penetrating agent that are dispersed in water. The ink is configured to have a point that the viscosity increase rate exceeds 50 when the water evaporation amount is 30% by mass or less and the water evaporation amount is 30% by mass to 45% by mass. Ink has been proposed in which the average particle diameter of the colorant in the ink at a viscosity increase rate exceeding 50 is not more than 5 times the initial average particle diameter and not more than 0.8 μm.

  Further, Patent Document 4 includes at least a colorant, a wetting agent, and a permeability improver that are dispersed in water in a maintenance and recovery device in an inkjet recording apparatus that records by discharging ink from the nozzles of an inkjet head. The viscosity increase rate (mPa · s /%) accompanying water evaporation is 1.0 or less up to a water evaporation rate of 30% with respect to the total mass of the ink, and the viscosity increase rate is between 30% and 45%. Covering means configured to have a point exceeding 50 and having a plurality of covering means for covering the head and suction force generating means connected to at least one covering means, and not communicating with the suction force generating means A maintenance / recovery device having at least one of the above has been proposed.

Further, Patent Document 5 contains a colorant composed of pigment-based fine particles, a wetting agent, a surfactant, a penetrating agent, and water, and increases the water evaporation rate of ink and the viscosity accompanying water evaporation. When the rate is expressed by the following formula, the rate of increase in viscosity is 10 or less up to a water evaporation rate of 30%, and the rate of increase in viscosity exceeds 500 between 30% and 50% of the water evaporation rate. Each ink in an ink-jet ink set has been proposed in which the average particle size of the colorant in the ink is up to 2% of the initial average particle size.
Moisture evaporation rate (%) = ((initial mass−mass after water evaporation) / initial mass) × 100
Viscosity increase rate = viscosity after water evaporation / initial viscosity

  As described above, many prior art documents relating to the equilibrium water content are disclosed, but the water content at the time of ink equilibrium can be obtained with a fairly high accuracy by the sum of approximate calculations from the equilibrium water content of a single wetting agent. If the amount of moisture evaporated matches the measured value, and the total amount of ink wetting agent and the amount of residual moisture at equilibrium are the same, even if the ink wetting agent type is different, the equilibrium regarding moisture at all humidity There is no disclosure or suggestion of good agreement.

  Patent Document 6, Patent Document 7 and Patent Document 8 include one or two kinds of wetting agents, and the amount of the wetting agent is 15% by mass to 25% by mass. Ink has been proposed in which a low alcohol is selected and it is a polyhydric alcohol having an amide bond or a polyhydric alcohol having a sulfone group. In this proposal, it is disclosed that the amount of water is also defined and curl prevention can be achieved. However, this proposal is not a combination of calculation of the equilibrium water content in an ink set composed of two or more inks.

  As described above, in the ink prescription design, viscosity matching, color tone matching, and the like are performed. However, an exact ink prescription design method for the equilibrium moisture content related to the ink reliability is not known. This is because it is possible to measure the equilibrium moisture content of each single wetting agent at each humidity when multiple types of wetting agents are included, but how it relates to the equilibrium moisture content in the ink, or It is not clear how it relates to humidity, and the current situation is that further improvements and development are desired.

Japanese Patent Application Laid-Open No. 64-5852 JP-A-6-287495 JP 2006-16412 A JP 2005-170035 A JP 2006-77232 A JP-A-2005-298913 JP 2005-297549 A JP 2005-297548 A

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, according to the present invention, the total amount of humectant for each ink and the residual moisture at equilibrium are the same even if the type and amount of humectant for each ink in the ink set and the solid content are different. Makes it possible to maintain a good balance of moisture at all humidity levels, prevent nozzle omission and jet bending, have high reliability, and prevent clogging, as well as ink media sets and ink jets using the ink sets. It is an object of the present invention to provide a recording method and an ink jet recording apparatus.

As a result of extensive studies by the present inventors in order to solve the above-mentioned problems, it is possible to calculate the total water content at the time of equilibrium in the ink by a simple sum of the equilibrium water content of each single wetting agent, with a considerably high accuracy. Even if the agent type and amount, and the solid content type are different, if the total amount of ink wetting agent and the amount of residual water at equilibrium are the same, changes in water such as water evaporation are relatively well matched at all humidity. It has been found that an ink set with even closer characteristics regarding water evaporation can be obtained if the total solid content is also preferably matched (inevitably the initial moisture content is also necessarily matched).
In addition, even if the wetting agent type and amount, and the solid content type are different for each color ink, the ink set that strictly designs the ink formulation with respect to the water balance is the amount of water evaporation at the time of ink equilibrium, It has been found that since the residual water amount is the same, the ink set is extremely preferable in terms of ink reliability.
Also, such an ink set shows a similar tendency not only in the equilibrium value but also in the water evaporation rate, and the final ink with a large amount of equilibrium water tends to be relatively small in the evaporation rate. I found out. This is because the difference from equilibrium in chemical equilibrium is similar to the situation where the reaction rate is proportional.

The present invention is based on the above findings by the present inventors, and means for solving the above problems are as follows. That is,
<1> In an ink set comprising a combination of two or more inks containing at least a colorant, a wetting agent, and a resin,
Each ink in the ink set includes at least one different type of wetting agent;
The ratio of the difference between the maximum value and the minimum value of the total amount of the wetting agent in each ink to the maximum value, and the difference between the maximum value and the minimum value of the residual moisture amount at equilibrium at a temperature of 23 ° C. and a humidity of 50% RH. The ink set is characterized in that the ratio to the maximum value is within 5%.
<2> The ratio of the difference between the maximum value and the minimum value of the initial water content in each ink to the maximum value, and the ratio of the difference between the maximum value and the minimum value of the solid content including the colorant and the resin to the maximum value The ink set according to <1>, wherein each is within 5%.
<3> Any one of <1> to <2>, wherein the wetting agent is at least one selected from glycerin, 1,3-butanediol, 3-methyl-1,3-butanediol, and 2-pyrrolidone. An ink set according to claim 1.
<4> The ink set according to any one of <2> to <3>, wherein a solid content in each ink is 10% by mass to 13% by mass, respectively.
<5> The ink set according to any one of <2> to <4>, wherein the initial moisture content in each ink is 44% by mass to 60% by mass.
<6> The ink set according to any one of <1> to <5>, wherein each ink in the ink set is at least one of magenta ink, cyan ink, yellow ink, and black ink.
<7> An ink media set comprising the ink set according to any one of <1> to <6> and a recording medium having an ink receiving layer on at least one surface of a support,
Pure water wherein the recording medium is, in the dynamic transfer amount to the recording medium of pure water at the contacting time 100ms measured by scanning absorptometer is is ^{2ml / m 2 ~35ml / m 2} , and the contact time 400ms an ink media set, wherein the amount of transferred to the recording medium is ^{3ml / m 2 ~40ml / m 2} .
<8> Inkjet comprising at least an ink flying step of recording an image by applying a stimulus to each ink of the ink set according to any one of <1> to <6> and causing the ink to fly It is a recording method.
<9> The ink jet recording method according to <8>, wherein each ink head corresponding to each ink in the ink set is covered with the same covering means and moisturized.
<10> The inkjet recording method according to any one of <8> to <9>, wherein each ink head corresponding to each ink in the ink set is simultaneously cleaned.
<11> The inkjet recording method according to any one of <8> to <10>, further including a drying step of drying an image recorded on the recording medium.
<12> The inkjet recording method according to any one of <8> to <11>, wherein each ink head corresponding to each ink in the ink set is a line-shaped head.
<13> An ink jet comprising at least ink flying means for recording an image by applying a stimulus to each ink of the ink set according to any one of <1> to <6> and causing the ink to fly. It is a recording device.

The ink set of the present invention is a combination of two or more inks containing at least a colorant, a wetting agent, and a resin.
Each ink in the ink set includes at least one different type of wetting agent;
The ratio of the difference between the maximum value and the minimum value of the total amount of the wetting agent in each ink to the maximum value, and the difference between the maximum value and the minimum value of the residual moisture amount at equilibrium at a temperature of 23 ° C. and a humidity of 50% RH. The ratio to the maximum value is within 5% each. As a result, the following effects (1) to (5) are exhibited, and it is suitable for ink jet recording. Furthermore, if the ratio of the difference between the maximum value and the minimum value of the solid content containing the colorant and the resin to the maximum value is within 5%, the difference in water evaporation between inks becomes smaller. It is more suitable to obtain the following effects (1) to (5).
(1) When the nozzles for the different color inks are moisturized with the same cover means (moisturizing cap), if the total amount of the wetting agent and the residual water content at equilibrium are the same for both inks, the evaporation balance is good. , Clogging is less likely to occur without moving moisture to either.
(2) In the case of a pigment having a relatively similar structure, when the moisture evaporation is the same, the maintenance and recovery operation, that is, the cleaning timing is the same. If the equilibrium water content is large, the cleaning timing must be matched to the ink that has a small residual water content and tends to dry and solidify early.
In particular, when there are two color ink nozzles in the same head, cleaning must be performed for both colors at the same time. Therefore, similar characteristics relating to moisture evaporation are effective in improving cleaning efficiency.
(3) If paper having a very low water absorption capability (for example, offset paper or art paper) is used, it takes a lot of time to dry after printing. If this is the same for each ink, there is no variation between the inks in the time required for drying after printing. Then, there is no waste in setting the printing speed.
(4) When a forced heating and drying process is required for paper having a low water absorption capacity, if the evaporation speed and amount of each ink are similar, there is no waste in drying energy and drying time. Otherwise, you will have to adjust to the slower evaporation.
(5) For high-speed printing with a line head, it is required to shorten the drying time after printing more strictly, there are nozzles that do not discharge for a long time, and the number of maintenance operations is limited. The above conditions become considerably strict, and it is more preferable that the water balance characteristics of each ink do not vary.

  According to the present invention, the conventional problems can be solved, and even if the type and amount of the wetting agent of each ink in the ink set and the solid content type are different, the total amount of the wetting agent of each ink and By matching the remaining water amount to the same amount, and also adding the total solid content (necessarily the initial water amount), the water-related equilibrium is well matched at all humidity, preventing nozzle omission and jet bending. Further, it is possible to provide an ink set that is highly reliable and hardly clogs, and an ink media set, an ink jet recording method, and an ink jet recording apparatus using the ink set.

(Ink set)
The ink set of the present invention is a combination of two or more inks containing at least a colorant, a wetting agent, and a resin.

In the present invention, each ink in the ink set includes at least one type of wetting agent. That is, each ink contains at least one different type of wetting agent.
For example, (1) when black ink and color ink come into contact with each other on the paper surface and bleeding occurs at the boundary, the wetting of each ink is necessary. When the type and amount of the agent is changed to make it difficult to be compatible at the boundary, (2) When it is difficult to penetrate the black ink into the color ink side, (3) Wet with good dispersion depending on the pigment type used for each ink When the kind of agent is different, etc. are mentioned.

  On the other hand, when the type of wetting agent is changed, the equilibrium moisture content differs between wetting agents. Therefore, the ink containing a wetting agent with a small equilibrium moisture content is different from the ink containing a wetting agent with a large equilibrium moisture content. The characteristics related to were different. Up to now, since the evaluation was individually performed for each ink based on the image quality and reliability, the advantages of sharing the characteristics related to the water evaporation of both were not noticed. Therefore, there has been a tendency to perform a cleaning operation in accordance with ink that dries relatively early or to determine a recording (printing) speed in accordance with ink that dries relatively late on the paper surface. As a result of intensive studies by the present inventors, it has been found that by combining the total amount of wetting agent and the equilibrium water content with each ink, such waste is eliminated and the ink becomes more ideal. This is possible because the equilibrium water content or water evaporation amount of the ink can be approximately calculated from the equilibrium water content data of each wetting agent alone, and it is found that it matches the actual measurement. In addition, the inventors have found a phenomenon that when the equilibrium water content of the ink is adjusted at a certain humidity in this way, it can be matched at the same prescription conditions at other humidity.

  The ratio [(ab) / a × 100%] of the difference between the maximum value (a) and the minimum value (b) of the total amount of the wetting agent in each ink to the maximum value (a) is within 5%, It is preferably 0% (same). If the ratio exceeds 5%, the total amount of the liquid portion in the ink (wetting agent and its equilibrium water content) will be deviated from the intended ink combination of the present invention to match between inks including after drying. Sometimes. Even if the difference ratio is not strictly within 5%, it is preferable that the difference between the inks is smaller.

  The said wetting agent shows the thing containing the equilibrium water | moisture content whose equilibrium water content is 1% or more at normal temperature (23 degreeC) and normal humidity (50% RH). Strictly speaking, the equilibrium moisture content of all components should be taken into account, but in practice, other additives are inherently only in small amounts in the ink. Further, since pigments and resins contained in a relatively large amount in the ink hardly retain moisture, there is no influence even if they are excluded from the calculation. However, an acrylic resin, an acrylic-silicone resin, a polyester resin, or the like having a low hygroscopic property is good, but in the case of a cellulose-based resin or the like having a high hygroscopic property, the influence must be considered.

  The wetting agent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include polyhydric alcohols, polyhydric alcohol alkyl ethers, polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides. , Amines, sulfur-containing compounds, propylene carbonate, ethylene carbonate and the like. These may be used alone or in combination of two or more.

Examples of the polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, 1,3-propanediol, 1,3-butanediol, 2,3-butanediol, 1,4 butanediol, 3-methyl-1,3-butanediol, 1,5 pentanediol, 1,6 hexanediol, 2-methyl-2,4-pentanediol, tetraethylene glycol Glycerin, 1,2,6-hexanetriol, 1,2,4-butanetriol, 1,2,3-butanetriol, petriol and the like.
Examples of the polyhydric alcohol alkyl ethers include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether, and the like. Can be mentioned.
Examples of the polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.
Examples of the nitrogen-containing heterocyclic compound include N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethylimidazolidinone, and ε-caprolactam.
Examples of the amides include formamide, N-methylformamide, N, N-dimethylformamide and the like.
Examples of the amines include monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine, and triethylamine.
Examples of the sulfur-containing compounds include dimethyl sulfoxide, sulfolane, thiodiethanol, thiodiglycol and the like.
Among these, glycerin, 2-pyrrolidone, diethylene glycol, thiodiethanol, polyethylene glycol, triethylene glycol, 1,2,6-hexanetriol, 1,2,4-butanetriol, petri from the viewpoint of ink ejection stability. All, 1,5-pentanediol, N-methyl-2-pyrrolidone, 1,3-butanediol, and 3-methyl-1,3-butanediol are preferred. Among these, glycerin, 1,3-butanediol, 3-methyl-1,3-butanediol and 2-pyrrolidone are particularly preferred.
In addition, as long as a solid type wetting agent, a polysaccharide such as sorbitol, or a cellulose resin type moisturizing agent is dissolved, it is counted as one kind of wetting agent. It should be noted that a resin having a strong viscosity such as a cellulose resin cannot be added in a large amount to the ink from the beginning, and its influence is small.
The total amount of wetting agent in each ink is preferably 15% by mass to 40% by mass. If the total amount of the wetting agent is less than 15% by mass, the ink ejection stability may be inferior. If it exceeds 40% by mass, the ink viscosity may be too high, and the ejection stability may be inferior.

In addition, the ratio [(a ′) of the difference between the maximum value (a ′) and the minimum value (b ′) of the residual moisture amount at equilibrium at a temperature of 23 ° C. and a humidity of 50% RH for each ink [( a′−b ′) / a ′ × 100%] is within 5%, and preferably 0% (same). If the ratio exceeds 5%, the characteristics relating to water evaporation between inks may be deviated from the object of the present invention to match between inks. Even if the difference ratio is not strictly within 5%, it is preferable that the difference between the inks is smaller.
The residual moisture amount at the time of equilibrium of the ink means the residual moisture amount when equilibrium is obtained in an environment of a temperature of 23 ° C. and a humidity of 50% RH when the initial ink amount is 100 parts by mass. The temperature and humidity are specified here in order to specify a value of 5%, and it has been clarified this time that if the equilibrium water content is the same at 23 ° C. and 50% RH, the other humidity is also the same.

When the mass ratio of the wetting agent i contained in the ink is Mi (mass%) and the equilibrium moisture content of the wetting agent alone at a humidity of 50% RH is Ei (mass%), the temperature is 23 ° C. and the humidity is 50% RH. The residual water content (Wt (mass%)) at the time of equilibrium of the ink is expressed by the following formula 1.
<Formula 1>
Wt = ΣMi × Ei / (100−Ei)
In Formula 1, i represents the wetting agent type, and Σ represents the sum of the wetting agents.
The equilibrium moisture content Ei of the humectant alone means the equilibrium moisture content of the humectant alone at a temperature of 23 ° C. and a humidity of 50% RH.
Ei is the percentage of moisture relative to the total mass when the wetting agent is a single type (i) of liquid and contains an equilibrium amount of moisture. That is, when the amount of wetting agent in a single wetting agent liquid is S (mass%) and the amount of water contained at the time of equilibration of the wetting agent is W (mass%), the equilibrium moisture content of the wetting agent ( Ei (mass%) is expressed by the following mathematical formula 2.
<Formula 2>
Ei = W / (S + W) × 100 (%)

Here, the equilibrium water content can be determined as follows. First, 0.5 g to 1 g (M) of a wetting agent is added to a petri dish having a diameter of 35 mm in a desiccator adjusted to a temperature of 23 ° C. and a humidity of 50% RH, and left until the mass becomes constant. The humidity inside the desiccator is always controlled with a hygrometer. When the humidity and temperature no longer change, the sample is weighed, and the equilibrium water content (E (%)) is obtained by the above formula 2.
Note that the temperature at the time of measuring the equilibrium water content is in an environment of 23 ° C., but the value of the equilibrium water content is greatly affected by humidity, but the fluctuation due to temperature is slight.
The humidity was adjusted with a saturated potassium carbonate solution (humidity of 44 to 45% RH), a saturated sodium chloride solution (humidity of about 76% RH), and a saturated potassium chloride solution (humidity of about 87% RH).
Humidity adjustment of low humidity (21% RH) was weighed when dried with silica gel and stabilized by external humidity adjustment. The exact humidity value was measured by placing a hygrometer inside the desiccator. Some of the wetting agents themselves evaporated slightly, but this was corrected.
The temperature environment is 23 ° C., but the value of the equilibrium moisture is not so much affected by temperature except in special cases such as the boiling point and freezing point. The wetting agent used was one with little moisture as impurities.
The residual water amount at equilibrium in each ink is the amount of water that can remain after evaporation of water relative to the initial ink total mass when left at a specific temperature and humidity. The higher this value, the higher the moisture retention. However, if it is too large, drying on the paper surface after printing will be slow (especially in the case of paper that is difficult for water to penetrate). The residual water content at the time of equilibrium is usually 2-3% to 10% at a temperature of 23 ° C. and a humidity of 50% RH.

It should be noted that if the total amount of solids is not extremely different between the inks, even if they are not matched, if the total amount of wetting agent and the amount of residual moisture at equilibrium match, it is consistent with the water evaporation in the latter half of the water evaporation. However, if the solid content is also adjusted between inks, the total solid content after water evaporation will match, so after equilibration, the solid content will also match in addition to the wetting agent amount and water content. As for the reliability characteristics such as the above, the ink becomes more common in characteristics.
The ratio of the difference between the maximum value (a ″) and the minimum value (b ″) of the solid content including the colorant and the resin in each ink to the maximum value (a ″) [(a ″ −b ″) / a ″ × 100%] is within 5%, and preferably 0% (same). If the ratio exceeds 5%, the characteristics relating to water evaporation between inks may be deviated from the object of the present invention to match between inks. Even if the difference ratio is not strictly within 5%, it is preferable that the difference between the inks is smaller.
It is mainly colorants and resins that are calculated as the solid content. That is, it shows a solid at room temperature alone. A solid wetting agent having an equilibrium moisture content of 1% or more at a temperature of 23 ° C. and a humidity of 50% RH is calculated as a wetting agent.
Among the colorants, although the dye is dissolved in the ink, it can also be applied to a dye-based ink in the sense that there is a possibility of fixation due to evaporation of moisture, but mainly corresponds to a pigment.
As the resin, an aqueous resin emulsion was mainly studied. A resin such as a pigment dispersant must be included in the calculation if the addition amount is large to some extent. These water-dispersible pigments and water-based resin emulsions have been confirmed to have negligible water retention capacity compared to wetting agents.
It is not directly related to the equilibrium of moisture, but directly related to the reliability when moisture is reduced, because the solid content (here, the solid content is the pigment and resin of the colorant) is the same for each ink. The same in the sense of doing.
The solid content in each ink is preferably 8% by mass to 20% by mass, more preferably 10% by mass to 13% by mass. When the solid content is less than 8% by mass, the image density tends to be inferior, and when it exceeds 20% by mass, the ejection reliability may be deteriorated.

Furthermore, the ratio [(cd) / c × 100%] of the difference between the maximum value (c) and the minimum value (d) of the initial water content in each ink to the maximum value (c) is within 5%. And is more preferably 0% (same). If the ratio exceeds 5%, the characteristics relating to water evaporation between the inks may deviate from the object of the present invention to match the characteristics between the inks. Even if the difference ratio is not strictly within 5%, it is preferable that the difference between the inks is smaller.
Here, the initial water content in each ink means the water content at the time of initial ink preparation excluding the pigment, the solid content of the resin, the wetting agent, and a small amount of additives.
The initial moisture content in each ink is preferably 44% by mass to 60% by mass, and more preferably 49% by mass to 54% by mass. When the initial water content is less than 44% by mass, the solid content or the total amount of the wetting agent is relatively increased, and the jetting stability is deteriorated due to a decrease in reliability or an increase in viscosity. On the other hand, if the initial water content exceeds 60% by mass, the solid content or the total amount of the wetting agent may be relatively reduced, and the image density and reliability may be lowered.

Directly related to the moisture balance was the amount of wetting agent in each ink, its equilibrium moisture content, and the initial moisture content. The solid content is related in the sense that the increase or decrease is indirectly related to the initial decrease or increase of the moisture content. Therefore, even if the solid content of each ink is different, it is also effective when the total amount of the wetting agent and the equilibrium water content are the same.
Pigments, resins, wetting agents, additives other than water, penetrating agents, pH adjusters, antiseptic / antifungal agents, antifoaming agents, and surface tension reducing surfactants that are colorants in each ink are added in small amounts. Therefore, it is not added to the calculation of equilibrium water content. However, it is preferable that at least the one with an equilibrium water content of 1% or more at a humidity of 50% RH and a large addition amount be included in the calculation of the equilibrium water as the same as the wetting agent.

Each ink in the ink set is preferably a yellow ink, a magenta ink, a cyan ink, or a black ink. When recording is performed using an ink set in which two or more of these colors are used in combination, a multicolor image is formed. When recording is performed using an ink set that is used in combination with all colors, a full-color image can be recorded.
Each ink in the ink set contains at least a colorant, a wetting agent, and a resin, and further contains a penetrating agent, a surfactant, and, if necessary, other components.

-Colorant-
As the colorant, either a pigment or a dye can be used, or a mixture of both can be used.
When a pigment is used as the colorant, an ink having excellent light resistance can be obtained. There is no restriction | limiting in particular as said pigment, The pigment for normal inkjet is used, The following are preferable.
(1) Pigment having a hydrophilic group on the pigment surface (2) Polymer emulsion type pigment comprising polymer fine particles containing a water-insoluble or poorly water-soluble coloring material (3) Micro-coated with a resin having a hydrophilic group Capsule type pigment

The pigment (1) is surface-modified so that at least one hydrophilic group is bonded to the surface of the pigment directly or via another atomic group. In the surface modification, a specific functional group (a functional group such as a sulfone group or a carboxyl group) is chemically bonded to the surface of the pigment, or at least one of hypohalous acid and a salt thereof is used. A method such as wet oxidation is used. Among these, a form in which a carboxyl group is bonded to the surface of the pigment and dispersed in water is particularly preferable. In this way, the surface of the pigment is modified and the carboxyl group is bonded, so not only the dispersion stability is improved, but also high-quality print quality is obtained and the water resistance of the recording medium after printing is further improved. To do.
In addition, since this form of ink has excellent redispersibility after drying, printing is paused for a long period of time, and clogging does not occur even when the ink moisture near the nozzles of the inkjet head evaporates, making it easy with a simple cleaning operation. Can print well.
The volume average particle diameter of the self-dispersing pigment is preferably 0.01 μm to 0.16 μm in the ink.

For example, as the self-dispersing carbon black, those having ionicity are preferable, and those having an anionic charge or those charged in a cationic form are suitable.
Examples of the anionic hydrophilic group include —COOM, —SO ₃ M, —PO ₃ HM, —PO ₃ M ₂ , —SO ₂ NH ₂ , —SO ₂ NHCOR (where M is a hydrogen atom, an alkali metal) And 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. 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.

  As the cationic hydrophilic group, for example, a quaternary ammonium group is preferable, and quaternary ammonium groups listed below are more preferable. In the present invention, any of these is bonded to the surface of carbon black. Suitable as a material.

  The method for producing the cationic self-dispersing carbon black to which the hydrophilic group is bonded is not particularly limited and may be appropriately selected depending on the intended purpose. For example, N-ethyl represented by the following structural formula An example of a method for bonding a pyridyl group is a method of treating carbon black with 3-amino-N-ethylpyridinium bromide.

The hydrophilic group may be bonded to the surface of the carbon black through another atomic group. Examples of the other atomic group include 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. Specific examples of the case where the above hydrophilic group is bonded to the surface of carbon black via another atomic group include, for example, —C ₂ H ₄ COOM (where M represents an alkali metal or quaternary ammonium). ), - PhSO ₃ M (however, Ph is a phenyl group .M represents an alkali metal or quaternary _{ammonium), - C 5 H 10 NH} 3 + , and the like.

In the pigment (2), the polymer emulsion containing a colorant means at least one of a polymer fine particle encapsulated with the pigment and a polymer fine particle surface adsorbed with the pigment. For example, what was described in Unexamined-Japanese-Patent No. 2001-139849 etc. are mentioned.
In this case, it is not necessary that all the pigments are encapsulated and / or adsorbed in the polymer fine particles, and the pigments may be dispersed in the emulsion as long as the effects of the present invention are not impaired.
The “water-insoluble or hardly 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. The term “dissolves” means that separation or sedimentation of the coloring material is not observed on the surface layer or lower layer of the aqueous solution.
The polymer that forms the polymer emulsion is not particularly limited and may be appropriately selected depending on the intended purpose. For example, vinyl polymers, polyester polymers, polyurethane polymers, JP 2000-53897 A, JP The polymer etc. which are indicated by 2001-139849 gazette are mentioned. Among these, vinyl polymers and polyester polymers are particularly preferable.
The volume average particle diameter of the polymer fine particles (colored fine particles) containing the coloring material is preferably 0.01 μm to 0.16 μm in the ink.
When the pigment (2) is used, an ink excellent in light resistance and fixability can be obtained.

The pigment (3) is obtained by coating the pigment with a hydrophilic water-insoluble resin and making it hydrophilic in the resin layer on the surface of the pigment so as to disperse the pigment in water. What was described in 2002-67473 gazette etc. are mentioned.
As a method for microencapsulating a water-insoluble pigment with an organic polymer, all conventionally known methods can be used.

There is no restriction | limiting in particular as a color development component of the said coloring agent, According to the objective, it can select suitably, For example, any of an inorganic pigment and an organic pigment may be sufficient.
Examples of the inorganic pigment include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow, and carbon black. Among these, carbon black is preferable. In addition, as said carbon black, what was manufactured by well-known methods, such as a contact method, a furnace method, and a thermal method, is mentioned, for example.

  Examples of the organic pigment include azo pigments, polycyclic pigments, dye chelates, nitro pigments, nitroso pigments, and aniline black. Among these, azo pigments and polycyclic pigments are more preferable. Examples of the azo pigment include azo lakes, insoluble azo pigments, condensed azo pigments, and chelate azo pigments. Examples of the polycyclic pigment include phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, and quinofullerone pigments. Examples of the dye chelates include basic dye chelates and acidic dye chelates.

There is no restriction | limiting in particular as a color of the said pigment, According to the objective, it can select suitably, For example, the thing for black, the thing for color, etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together.
Examples of the black color include carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, copper, iron (CI pigment black 11), oxidation, and the like. Examples thereof include metals such as titanium, organic pigments such as aniline black (CI pigment black 1), and the like.

As for the color, for yellow ink, for example, C.I. I. Pigment Yellow 1 (Fast Yellow G), 3, 12 (Disazo Yellow AAA), 13, 14, 17, 23, 24, 34, 35, 37, 42 (Yellow Iron Oxide), 53, 55, 74, 81, 83 (Disazo Yellow HR), 95, 97, 98, 100, 101, 104, 108, 109, 110, 117, 120, 128, 138, 150, 153, and the like.
For magenta, for example, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22 (Brilliant First Scarlet), 23, 31, 38, 48: 2 (Permanent Red 2B (Ba)), 48: 2 (Permanent Red 2B (Ca)), 48 : 3 (Permanent Red 2B (Sr)), 48: 4 (Permanent Red 2B (Mn)), 49: 1, 52: 2, 53: 1, 57: 1 (Brilliant Carmine 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81 (Rhodamine 6G Lake), 83, 88, 92, 101 (Bengara), 104, 105, 106, 108 (Cadmium Red), 112, 114, 122 (Dimethylquinacridone), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 185, 190, 193, 209, 2 9, and the like.
For cyan, for example, C.I. I. Pigment Blue 1, 2, 15 (copper phthalocyanine blue R), 15: 1, 15: 2, 15: 3 (phthalocyanine blue G), 15: 4, 15: 6 (phthalocyanine blue E), 16, 17: 1, 56, 60, 63 and the like.
In addition, as the intermediate colors for red, green and blue, C.I. I. Pigment red 177, 194, 224, C.I. I. Pigment orange 43, C.I. I. Pigment violet 3, 19, 23, 37, C.I. I. Pigment green 7, 36, and the like.

When a dye is used as the colorant, an ink excellent in color tone can be obtained. Examples of the dye include water-soluble dyes, oil-soluble dyes, and disperse dyes.
The water-soluble dye is a dye classified into an acid dye, a direct dye, a basic dye, a reactive dye, and a food dye in the color index, and preferably has excellent water resistance and light resistance.
Examples of the acid dyes and food dyes include 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; I. Acid Blue 9, 29, 45, 92, 249; I. Acid Black 1, 2, 7, 24, 26, 94; I. Food Yellow 3, 4; I. Food red 7, 9, 14; I. Food black 1, 2 etc. are mentioned.
Examples of the direct dye include C.I. I. Direct yellow 1,12,24,26,33,44,50,86,120,132,142,144; 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; I. Direct black 19, 22, 32, 38, 51, 56, 71, 74, 75, 77, 154, 168, 171 and the like.
Examples of the basic dye include 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, 64, 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.
Examples of the reactive dye include 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; I. Reactive Red 1,14,17,25,26,32,37,44,46,55,60,66,74,79,96,97; I. Reactive blue 1, 2, 7, 14, 15, 23, 32, 35, 38, 41, 63, 80, 95, and the like.

-Resin-
There is no restriction | limiting in particular as said resin, Although it can select suitably according to the objective, A resin fine particle is preferable from the point which can add the addition amount of resin.
The resin fine particles present as a resin emulsion dispersed in water as a continuous phase are used at the time of ink production. The resin emulsion may contain a dispersant such as a surfactant as necessary.
The content of the resin fine particles as the dispersed phase component (content of resin fine particles in the resin emulsion solution: not the content in each ink in the ink set after production) is generally 10% by mass to 70% by mass. % Is preferred.
Further, the particle diameter of the resin fine particles is preferably 10 nm to 1,000 nm, more preferably 100 nm to 300 nm, particularly considering use in an ink jet recording apparatus. This is the particle diameter in the resin emulsion, but in the case of each ink in a stable ink set, there is no significant difference between the particle diameter in the resin emulsion and the resin fine particle diameter in each ink in the ink set. The larger the volume average particle diameter is, the more emulsion can be added. If the volume average particle size is less than 100 nm, the amount of emulsion added may not be increased, and if it exceeds 300 nm, the reliability may be lowered. However, it is not always possible to use an emulsion having a particle size outside this range. These are general trends regardless of the type of emulsion.
Here, the volume average particle diameter can be measured using, for example, a particle size analyzer (Microtrac Model UPA9340, manufactured by Nikkiso Co., Ltd.). Here, the value of 50% was defined as the volume average particle size.

The resin particles in the dispersed phase are not particularly limited and can be appropriately selected according to the purpose. For example, urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, Examples include styrene-butadiene resins, vinyl chloride resins, acrylic-styrene resins, acrylic-silicone resins, and the like.
As said resin emulsion, what was synthesize | combined suitably may be used and a commercial item may be used.
Examples of the commercially available resin emulsion include Microgel E-1002, E-5002 (styrene-acrylic resin emulsion, manufactured by Nippon Paint Co., Ltd.), and Boncoat 4001 (acrylic resin emulsion, manufactured by Dainippon Ink & Chemicals, Inc.). ), Boncoat 5454 (styrene-acrylic resin emulsion, manufactured by Dainippon Ink & Chemicals, Inc.), SAE-1014 (styrene-acrylic resin emulsion, manufactured by Nippon Zeon Co., Ltd.), Cybinol SK-200 (acrylic resin emulsion, Seiden Chemical Co., Ltd.), Primal AC-22, AC-61 (acrylic resin emulsion, manufactured by Rohm and Haas), Nanocryl SBCX-2821, 3689 (acrylic-silicone resin emulsion, Toyo Ink Co., Ltd.) Ltd. Formula Company), # 3070 (methyl methacrylate polymer resin emulsion, manufactured by Mikuni Color Ltd.). Among these, an acrylic silicone emulsion is particularly preferable from the viewpoint of good fixability.

  As the penetrant, a polyol compound having 8 to 11 carbon atoms or a glycol ether compound is used. At least one of these polyol compounds and glycol ether compounds has an effect of increasing the penetration rate into paper and preventing bleeding, and has a solubility of 0.1% by mass to 4.5% by mass in water at 25 ° C. It has a partially water-soluble compound.

  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 alkyl ether compounds and polyhydric alcohol aryl ether compounds.
Examples of the polyhydric alcohol alkyl ether compound include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether and the like. It is done.
Examples of the polyhydric alcohol aryl ether compound include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

  The content of the penetrant in each ink in the ink set is preferably 10% by mass or less, and more preferably 0.5% by mass to 5% by mass.

-Surfactant-
The surfactant is not particularly limited and can be appropriately selected from surfactants that do not impair dispersion stability depending on the purpose, depending on the type of coloring agent, a wetting agent, a penetrating agent, and the like. In particular, when printing on printing paper, those having low surface tension and high leveling properties are preferred, and at least one selected from silicone surfactants and fluorosurfactants is preferred. Among these, a fluorine-based surfactant is particularly preferable.

The fluorine-based surfactant preferably has 2 to 16 carbon atoms substituted by fluorine, and more preferably 4 to 16 carbon atoms. When the fluorine-substituted carbon number is less than 2, the effect of fluorine may not be obtained, and when it exceeds 16, problems such as ink storage stability may occur.
Examples of the fluorosurfactant include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic compound, a perfluoroalkyl phosphate compound, a perfluoroalkyl ethylene oxide adduct, and a perfluoroalkyl ether group in the side chain. And polyoxyalkylene ether polymer compounds. Among these, a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain is particularly preferable because of its low foaming property.

Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid, perfluoroalkyl sulfonate, and the like.
Examples of the perfluoroalkyl carboxylic compounds include perfluoroalkyl carboxylic acids and perfluoroalkyl carboxylic acid salts.
Examples of the perfluoroalkyl phosphate compound include perfluoroalkyl phosphate esters, perfluoroalkyl phosphate salts, and the like.
The polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain includes a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain, and a polyoxyalkylene ether having a perfluoroalkyl ether group in the side chain. Examples thereof include a sulfate salt of a polymer and a salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain.
As counter ions of salts in these fluorosurfactants, Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , NH (CH ₂ CH ₂ OH) ₃ etc. are mentioned.

As said fluorosurfactant, what was synthesize | combined suitably may be used and a commercial item may be used.
Examples of the commercially available products include Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, and S-145 (all manufactured by Asahi Glass Co., Ltd.); Fullrad FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M Limited); Megafac F-470, F1405 , F-474 (all manufactured by Dainippon Ink & Chemicals, Inc.); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR (all manufactured by DuPont) FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW (all manufactured by Neos Co., Ltd.); PF 151N (manufactured by Omninova) and the like. Among these, FT-110, FT-250, and FT- manufactured by Neos Co., Ltd. are particularly preferable in terms of remarkably improving good print quality, particularly color developability and leveling on paper. 251, FT-400S, FT-150, FT-400SW and OM-nova PF-151N are particularly preferred.
As specific examples of the fluorosurfactant, those represented by the following structural formula are suitable.

(1) Anionic fluorosurfactant
However, in the structural formula, Rf represents a mixture of fluorine-containing hydrophobic groups represented by the following structural formula. A is —SO ₃ X, —COOX, or —PO ₃ X (where X is a counter anion, specifically, a hydrogen atom, Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, , NH ₂ (CH ₂ CH ₂ OH) ₂ , or NH (CH ₂ CH ₂ OH) ₃ ).

In the structural formula, Rf ′ represents a fluorine-containing group represented by the following structural formula. X represents the same meaning as described above. n represents an integer of 1 or 2, and m represents 2-n.
However, in said structural formula, n represents the integer of 3-10.

However, in the structural formulas, Rf ′ and X have the same meaning as described above.

However, in the structural formulas, Rf ′ and X have the same meaning as described above.

(2) Nonionic fluorosurfactant
In the structural formula, Rf represents the same meaning as described above. n represents an integer of 5 to 20.

In the structural formula, Rf ′ represents the same meaning as described above. n represents an integer of 1 to 40.

(3) Amphoteric fluorosurfactant
However, in the structural formula, Rf represents the same meaning as described above.

(4) Oligomer type fluorosurfactant
In the structural formula, Rf ″ represents a fluorine-containing group represented by the following structural formula. N represents an integer of 0 to 10. X represents the same meaning as described above.
However, in said structural formula, n represents the integer of 1-4.

In the structural formula, Rf ″ represents the same meaning as described above. L represents an integer of 0 to 10, m represents an integer of 0 to 10, and n represents an integer of 0 to 10, respectively.

The silicone-based surfactant is not particularly limited and can be appropriately selected depending on the purpose, and preferably does not decompose even at a high pH. For example, side chain-modified polydimethylsiloxane, both-end modified polydimethylsiloxane, Examples include one-end-modified polydimethylsiloxane, side-chain both-end-modified polydimethylsiloxane, and those having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as a modifying group exhibit good properties as an aqueous surfactant. Particularly preferred.
As such a surfactant, an appropriately synthesized product or a commercially available product may be used.
Such commercially available products can be easily obtained from, for example, Big Chemie, Shin-Etsu Silicone, Toray Dow Corning Silicone, etc.

The polyether-modified silicone surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the polyalkylene oxide structure represented by the following structural formula may be represented by the side chain of Si part of dimethylpolysiloxane. And the like, and the like.
However, m, n, a, and b represent an integer in the said structural formula. R and R ′ each represents an alkyl group or an alkylene group.

  A commercial item can be used as said polyether modified silicone compound, For example, KF-618, KF-642, KF643 (all are the Shin-Etsu Chemical Co., Ltd. product) etc. are mentioned.

  In addition to the fluorine surfactant and the silicone surfactant, an anionic surfactant, a nonionic surfactant, an amphoteric surfactant, and the like can be used.

  Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, oxalate sulfonate, laurate, and polyoxyethylene alkyl ether sulfate salt.

Examples of the nonionic surfactant include acetylene glycol surfactants, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan fatty acid esters, and the like.
Examples of the acetylene glycol surfactants include 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3,5-dimethyl-1-hexyn-3-ol and the like can be mentioned. Examples of commercially available acetylene glycol surfactants include Surfynol 104, 82, 465, 485, and TG manufactured by Air Products (USA).

Examples of the amphoteric surfactant include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, lauryl dihydroxyethyl betaine, lauryl dimethylamine oxide, myristyl dimethylamine oxide, stearyl dimethylamine oxide, dihydroxyethyl lauryl amine oxide, Polyoxyethylene coconut oil alkyldimethylamine oxide, dimethylalkyl (coconut) betaine, dimethyl lauryl betaine and the like can be mentioned.
As such surfactants, commercially available products are Nikko Chemicals Co., Ltd., Nippon Emulsion Co., Ltd., Nippon Shokubai Co., Ltd., Toho Chemical Co., Ltd., Kao Co., Ltd., Adeka Co., Ltd., Lion Co., Ltd., Aoki Yushi Co., Ltd., Sanyo It can be easily obtained from Kasei Kogyo Co., Ltd.
The surfactant is not limited to these, and may be used alone or in combination. Even if it does not dissolve easily in each ink in the ink set by itself, it can be solubilized by mixing and exist stably.

Among these surfactants, those represented by the following structural formulas (1) to (5) are preferable.
^{_{R 1 -O- (CH 2 CH 2}} O) h -R 2 ··· structural formula (1)
However, in said structural formula (1), R < ¹ > represents the C6-C14 alkyl group which may be branched, or the C6-C14 perfluoroalkyl group which may be branched. R ² represents a hydrogen atom or an optionally branched alkyl group having 1 to 4 carbon atoms. h represents an integer of 5 to 20.

^{_{R 1 -COO- (CH 2 CH 2}} O) h -R 2 ··· structural formula (2)
However, the in the structural formula (2), R ¹ represents an alkyl group which may be branched having 6 to 14 carbon atoms. R ² represents a hydrogen atom or an optionally branched alkyl group having 1 to 4 carbon atoms. h represents an integer of 5 to 20.

In the Structural formula (3), R ³ represents a hydrocarbon group, for example, such as an alkyl group branched carbon atoms and optionally 6-14. k represents an integer of 5 to 20.

However, the structural formula (4), R ⁴ represents a hydrocarbon group, for example, an alkyl group branched carbon atoms and optionally 6-14. L represents an integer of 5 to 10, and p represents an integer of 5 to 20. The propylene glycol chain and the ethylene glycol chain may be block polymerized or randomly polymerized.

However, in said structural formula (5), q and r represent the integer of 5-20, respectively.

  The content of the surfactant in each ink in the ink set is preferably 0.01% by mass to 3.0% by mass, and more preferably 0.5% by mass to 2% by mass. When the content is less than 0.01% by mass, the effect of adding a surfactant may be lost. When the content exceeds 3.0% by mass, the permeability to a recording medium becomes higher than necessary. In some cases, a decrease in image density or a show-through may occur.

  There is no restriction | limiting in particular as said other component, It can select suitably as needed, For example, an antifoamer, antiseptic / antifungal agent, antirust agent, pH adjuster, specific resistance adjuster, antioxidant , Ultraviolet absorbers, oxygen absorbers, light stabilizers, viscosity modifiers, and the like.

  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, the emulsion type silicone antifoaming agent, and the like are preferable in consideration of use for each ink in the ink set 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 each ink in the said ink set of the said antifoamer, According to the objective, it can select suitably, For example, 0.001 mass%-3 mass% are preferable, 0.05 A mass% to 0.5 mass% is more preferable.

Examples of the antiseptic / antifungal agent include 1,2-benzisothiazolin-3-one, sodium dehydroacetate, sodium sorbate, sodium 2-pyridinethiol-1-oxide, sodium benzoate, and sodium pentachlorophenol. Can be mentioned.
As the specific resistance adjuster, an inorganic salt, for example, an alkali metal halide or an ammonium halide (for example, lithium chloride, ammonium chloride, sodium chloride) or the like is used to charge each ink in the ink set. A recording liquid used in the ink jet recording method can be prepared.

  The pH adjuster is not particularly limited as long as the pH can be adjusted to 7 or more without adversely affecting the ink to be prepared, and any substance can be used according to the purpose. For example, diethanolamine , Amines such as triethanolamine, hydroxides of alkali metal elements such as lithium hydroxide, sodium hydroxide, potassium hydroxide; ammonium hydroxide, quaternary ammonium hydroxide, quaternary phosphonium hydroxide, carbonic acid Examples thereof include alkali metal carbonates such as lithium, sodium carbonate, and potassium carbonate.

  Examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

Examples of the antioxidant include phenol-based antioxidants (including hindered phenol-based antioxidants), amine-based antioxidants, sulfur-based antioxidants, phosphorus-based antioxidants, and the like.
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-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tetrakis [methylene-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) 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 can be mentioned.
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, and trinonylphenyl phosphite.

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 UV absorber include phenyl salicylate, p-tert-butylphenyl salicylate, p-octylphenyl salicylate, and the like.
Examples of the cyanoacrylate 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.

  Each ink in the ink set of the present invention contains a colorant and a resin and is a solid component that is solid at 25 ° C., a liquid component that has a boiling point higher than water and is liquid at 25 ° C., water, and other if necessary These components are dispersed or dissolved in an aqueous medium, and further, stirred and mixed as necessary. In general, a colorant and a resin that are previously dissolved or dispersed in water are used. The dispersion can be performed by, for example, a sand mill, a homogenizer, a ball mill, a paint shaker, an ultrasonic disperser, etc., and stirring and mixing are performed by a stirrer using a normal stirring blade, a magnetic stirrer, a high-speed disperser, or the like. be able to.

  The physical properties of each ink in the ink set of the present invention are not particularly limited and can be appropriately selected according to the purpose. For example, the viscosity, surface tension, pH, and the like are preferably in the following ranges.

The viscosity of each ink in the ink set is preferably 1.0 mPa · s to 20 mPa · s, more preferably 3.0 mPa · s to 15 mPa · s at 25 ° C. If the viscosity exceeds 20 mPa · s, it may be difficult to ensure ejection stability. However, depending on the head structure, it cannot always be used.
The surface tension of each ink in the ink set is preferably 20 mN / m to 50 mN / m, more preferably 25 mN / m to 45 mN / m at 25 ° C. When the surface tension exceeds 50 mN / m, leveling of the ink on the recording medium hardly occurs and the drying time may be prolonged.
The pH of each ink in the ink set is preferably 7 to 11, for example.

  Each ink in the ink set of the present invention is an ink-jet head that uses a piezoelectric element as pressure generating means for pressurizing the ink in the ink flow path, and deforms the diaphragm that forms the wall surface of the ink flow path to change the contents of the ink flow path. A so-called piezo-type device that discharges ink droplets by changing the product (see Japanese Patent Laid-Open No. 2-51734), or a so-called thermal device that generates bubbles by heating ink in an ink flow path using a heating resistor. Type (see Japanese Patent Application Laid-Open No. 61-59911), the diaphragm and the electrode forming the wall surface of the ink flow path are arranged opposite to each other, and the diaphragm is deformed by the electrostatic force generated between the diaphragm and the electrode Ink jet heads such as an electrostatic type that discharges ink droplets by changing the volume in the ink flow path (see JP-A-6-71882) It can be used well for printers equipped with.

  Each ink in the ink set of the present invention can be suitably used in various fields, and can be suitably used in an image recording apparatus (printer or the like) by an ink jet recording method. For example, printing or recording before and after printing Each ink in the paper and the ink set 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, and ink jet recording apparatus of the present invention The ink jet recording method can be particularly preferably used.

<Ink cartridge>
The ink cartridge used in the present invention contains each ink in the ink set of the present invention in a container, and further includes other members 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. Preferred examples include those possessed.

Next, the ink cartridge will be described with reference to FIGS. Here, FIG. 1 is a view showing an example of the ink cartridge, and FIG. 2 is a view including a case (exterior) of the ink cartridge of FIG.
As shown in FIG. 1, the ink cartridge 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. 2, the ink bag 41 is usually accommodated 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, and the like.
The ink jet recording method of the present invention includes at least an ink flying process, and further includes other processes appropriately selected as necessary, for example, a stimulus generation process, a control process, and the like.
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 each ink in the ink set of the present invention and causing each ink in the ink set to fly.
The ink flying means is means for forming an image by applying a stimulus to each ink in the ink set of the present invention and causing each ink in the ink set to fly. The ink flying means is not particularly limited and may be appropriately selected according to the purpose. Examples thereof include various recording heads (ink discharge heads), and particularly a head having a plurality of nozzle rows and a liquid storage. It is preferable to have a sub-tank that contains the liquid supplied from the tank for supplying the liquid to the head.
The sub tank includes negative pressure generating means for generating a negative pressure in the sub tank, atmospheric release means for releasing the inside of the sub tank to the atmosphere, and detection means for detecting the presence or absence of ink based on a difference in electrical 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, and a light. Specifically, 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, a shape memory alloy actuator that uses a metal phase change caused by a temperature change, For example, an electrostatic actuator using an electrostatic force may be used.

There is no particular limitation on the manner of flying of each ink in the ink set, and it varies depending on the type of the stimulus. For example, when the stimulus is “heat”, for each ink in the ink set in the recording head, The thermal energy corresponding to the recording signal is applied using, for example, a thermal head, bubbles are generated in each ink in the ink set by the thermal energy, and the ink is discharged from the nozzle holes of the recording head by the pressure of the bubbles. And a method of ejecting and ejecting each ink in the set as droplets. 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 a method of ejecting and ejecting each ink in the ink set as droplets from the nozzle holes of the recording head.
A method in which a voltage is applied to the piezo element to cause each ink in the ink set to fly is preferable. Since the piezo method does not generate heat, it is advantageous for flying ink containing resin, and is an effective method with less nozzle clogging, particularly when ink containing a small amount of wetting agent is used.
In order to prevent nozzle omission, it is preferable to perform a blank scan by applying a voltage having a strength that does not eject ink to the piezo element. Furthermore, it is preferable to perform an operation of discharging ink to the ink reservoir before reaching the empty scan for one page printing.

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.
It is preferable that each ink head is individually provided with a cover means (moisturizing cap). However, in order to secure space and share the maintenance device, the two color heads may be covered with the same cover means to keep the moisture. is there.
When the two color heads are covered and moisturized by the same cover means, the ink heads corresponding to the inks of the ink set can be cleaned simultaneously, and the number of cleanings can be reduced. However, if the difference between the water evaporation characteristics of the two inks is large, cleaning cannot be performed efficiently, so it is effective to strictly match the water evaporation characteristics as in this patent.
In some cases, each ink head corresponding to each ink in the ink set is formed in a line shape in order to eliminate sub-scanning and perform high-speed printing.

In the ink jet recording method of the present invention, when printing on paper having a low water absorption capability, it is preferable to include a drying step of drying the image recorded on the recording medium in order to increase the drying speed. As a drying method, either a method of providing a drying step before recording or a method of providing after recording may be used.
The drying means may be one that applies microwave energy to the recording medium using microwave energy, or a non-contact type such as a heating wire type. Further, a contact type (for example, a heating roller) may be provided separately. The roller itself may be directly heated, or the roller may be indirectly heated from another heat source.

  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. FIG. 3 is a schematic view showing an example of the ink jet recording apparatus of the present invention. The ink jet recording apparatus shown in FIG. 3 includes 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 for stocking and an ink cartridge loading unit 6 are provided. 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.

  As shown in FIGS. 4 and 5, in the apparatus main body 1, the carriage 13 is slid in the main scanning direction by a guide rod 11 and a stay 12 which are guide members horizontally mounted on left and right side plates (not shown). It is held movably and moved and scanned in the direction of the arrow in FIG. 5 by a main scanning motor (not shown).

The carriage 13 includes a plurality of recording heads 14 including four inkjet recording heads that discharge ink droplets in each color ink set of yellow (Y), cyan (C), magenta (M), and black (Bk). Are arranged in a direction crossing the main scanning direction, and the ink droplet ejection direction is directed 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 provided as energy generating means for discharging each ink in the ink set 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 each ink in the ink set of the present invention from the ink cartridge 10 of the present invention loaded in the ink cartridge loading section 6 via each ink supply tube in the ink set (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 mounted on 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.
When it is detected that the remaining amount of each ink in the ink set in the sub tank 15 has decreased, each ink in the required amount of ink set 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, the recording head 14 (used to collectively refer to a plurality of heads), for example, as shown in FIG. 6, is a nozzle array 14yn composed of a number of nozzles N that eject yellow (Y) ink droplets and magenta ( M) a droplet discharge head 14a having a nozzle row 14mn including a number of nozzles N that discharge ink droplets of M, a nozzle row 14cn including a number of nozzles N that discharge cyan (C) ink droplets, and black (Bk) And a head 14b having a nozzle row 14kn composed of a large 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 provided, 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.

The example of FIG. 6 shows an ink jet printer (IPSiO G505, manufactured by Ricoh Co., Ltd.), and nozzles for discharging different color inks are provided side by side on the same head.
In addition, in the ink jet printer (IPSiO G707, manufactured by Ricoh Co., Ltd.), four heads having the same structure are provided, and yellow, magenta, cyan, and black inks are respectively provided.

  As the ink-jet head constituting the recording head 14, a piezoelectric actuator such as a piezoelectric element, a thermal actuator that utilizes 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 main tank (ink cartridge) 10 of each color described above is supplied to the sub tank 15 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). Ink 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. 7 is an exploded perspective view of a portion related to the ink supply device, FIG. 8 is a detailed view thereof, and FIG. 9 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, a film of polyethylene and nylon It is possible to adopt a configuration in which a cylindrical member is laminated, or 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.
The thickness of the film-like member 102 is preferably 10 μm to 100 μm. When the thickness is less than 10 μm, damage due to deterioration over time may easily occur. When the thickness exceeds 100 μm, flexibility may be reduced and it may be difficult to efficiently generate negative pressure. .
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 whose opening faces the ink storage unit 100 and a flow path portion (referred to as an “orthogonal flow path portion”) 123 following the inlet flow path portion 122. Further, 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 is further below the atmosphere opening hole 131 in the use state.

  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 has become a predetermined amount or less (this state is referred to as “no ink”) are attached to the upper portion of the case 101. Yes. 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. 11 and 12, the ink jet recording apparatus of the present invention maintains the state of the nozzles of the recording head 14 in the non-printing region 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. 11 is a top view of the maintenance / recovery mechanism, and FIG. 12 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, and a wiper blade 73 for wiping the nozzle surface. 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.

Next, the maintenance / recovery mechanism 71 according to the ink jet recording apparatus of the present invention will be described.
As shown in FIGS. 11 and 12, first, when the motor 231 rotates in the forward direction, 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 operates to operate the pump. 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 media set)
The ink media set of the present invention comprises the ink set of the present invention and a recording medium, and further has other configurations as necessary.

<Recording media>
The recording medium includes a support and an ink receiving layer on at least one surface of the support, and further includes other layers as necessary.

As the recording medium, in addition to so-called high-quality paper or PPC paper (so-called plain paper) that easily absorbs normal water, ink-jet exclusive paper coated with a water-absorbing layer may be used. However, when printing on the following recording media, which are difficult to absorb water and are generally not suitable for water-based inkjet, there is a strong demand for shortening the drying time. When the characteristics related to water evaporation are combined as in the present invention, it is effective to make the drying time common to each ink.
As such a recording medium, the amount of transferred to the recording medium of pure water at the contacting time 100ms measured by a dynamic scanning absorptometer ^{is 2ml / m 2 ~35ml / m 2} , 2ml / m there is a ^{2 ~10ml} / ^{m 2.}
If the transfer amount of the ink and pure water at the contact time of 100 ms is too small, beading is likely to occur. If it is too large, the ink dot diameter after recording becomes too smaller than the desired diameter. There is.
The transfer amount of the pure water to the recording medium at a contact time of 400 ms measured with a dynamic scanning absorption meter is 3 ml / m ^{2 to} 40 ml / m ² , and 3 ml / m ^{2 to} 10 ml / m ^2. Is preferred.
If the amount of transfer at the contact time of 400 ms is too small, the drying property is insufficient, and thus spur marks may be easily generated. If the amount is too large, the gloss of the image area after drying tends to be low. There is.

  Here, the dynamic scanning absorptiometer (DSA, Papa-Pagi Technical Journal, Vol. 48, May 1994, pp. 88-92, Kuju Shigenori) absorbs liquid in a very short time. It is a device that can measure accurately. The dynamic scanning absorption meter reads the liquid absorption speed directly from the movement of the meniscus in the capillary, makes the sample a disk, and then scans the liquid absorption head in a spiral shape, and the scanning speed according to a preset pattern. Is automatically changed by a method in which the number of necessary points is measured with one sample. A liquid supply head for a paper sample is connected to a capillary via a Teflon (registered trademark) tube, and the position of the meniscus in the capillary is automatically read by an optical sensor. Specifically, the transfer amount of pure water or ink was measured using a dynamic scanning absorption meter (K350 series D type, manufactured by Kyowa Seiko Co., Ltd.). The transfer amount at the contact time of 100 ms and the contact time of 400 ms can be obtained by interpolation from the measured value of the transfer amount at the contact time adjacent to each contact time.

-Support-
The support is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include paper based on wood fibers, and sheet-like materials such as non-woven fabrics mainly composed of wood fibers and synthetic fibers. .

  There is no restriction | limiting in particular as said paper, According to the objective, it can select suitably according to the objective, For example, wood pulp, waste paper pulp, etc. are used. Examples of the wood pulp include hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), NBSP, LBSP, GP, and TMP.

  As the raw material of the used paper pulp, the white paper, ruled white, cream white, card, special white, medium white, imitation, fair white, Kent, white, as shown in the used paper standard quality standard table of the used paper recycling promotion center Art, special upper limit, another upper limit, newspaper, magazine, etc. are mentioned. Specifically, printer paper such as non-coating computer paper, thermal paper, and pressure-sensitive paper as information-related paper; OA waste paper such as PPC paper; coating of art paper, coated paper, finely coated paper, matte paper, etc. Paper: High quality paper, color quality, notebook, notepaper, wrapping paper, fancy paper, medium quality paper, newsprint, reprint paper, super paper, imitation paper, pure white roll paper, uncoated paper such as milk carton, etc. Examples of used paper and paperboard include chemical pulp paper and high-yield pulp-containing paper. These may be used individually by 1 type and may use 2 or more types together.

The waste paper pulp is generally produced from a combination of the following four steps.
(1) For disaggregation, waste paper is treated with mechanical force and chemicals with a pulper to loosen it into a fibrous form, and the printing ink is peeled off from the fiber.
(2) Dust removal is to remove foreign matter (plastic etc.) and dust contained in waste paper with a screen, cleaner or the like.
(3) In the deinking, the printing ink peeled off from the fiber using a surfactant is removed from the system by a flotation method or a cleaning method.
(4) Bleaching increases the whiteness of the fiber using an oxidizing action or a reducing action.
When mixing the used paper pulp, the mixing ratio of the used paper pulp in the total pulp is preferably 40% or less from the viewpoint of curling after recording.

  As the internal filler used for the support, for example, a conventionally known pigment is used as a white pigment. Examples of the white pigment include light calcium carbonate, heavy calcium carbonate, kaolin, clay, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, White inorganic pigments such as calcium silicate, magnesium silicate, synthetic silica, aluminum hydroxide, alumina, lithopone, zeolite, magnesium carbonate, magnesium hydroxide; styrene plastic pigment, acrylic plastic pigment, polyethylene, microcapsule, urea resin And organic pigments such as melamine resin. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the internally added sizing agent used for making the support include neutral rosin sizing agents used for neutral papermaking, alkenyl succinic anhydride (ASA), alkyl ketene dimer (AKD), and petroleum resins. System sizing agents and the like. Among these, a neutral rosin sizing agent or alkenyl succinic anhydride is particularly preferable. The alkyl ketene dimer may be added in a small amount because of its high size effect, but the friction coefficient on the surface of the recording medium tends to be slippery, which may be undesirable from the viewpoint of transportability during ink jet recording. .

-Ink receiving layer-
The ink receiving layer contains a pigment and a binder (binder), and further contains a surfactant and other components as necessary.

As the pigment, an inorganic pigment or a combination of an inorganic pigment and an organic pigment can be used.
The inorganic pigment is not particularly limited and may be appropriately selected depending on the intended purpose. For example, kaolin, talc, heavy calcium carbonate, light calcium carbonate, calcium sulfite, amorphous silica, titanium white, magnesium carbonate , Titanium dioxide, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, chlorite and the like. Among these, kaolin is particularly preferable because it has excellent glossiness and can be made close to a paper for offset printing.
The kaolin includes delaminated kaolin, calcined kaolin, engineered kaolin by surface modification, etc. In consideration of gloss expression, the particle size distribution is such that the proportion of particle size of 2 μm or less is 80% by mass or more. It is preferable that the kaolin which has occupies 50 mass% or more of the whole kaolin.
The amount of kaolin added is preferably 50 parts by mass or more with respect to 100 parts by mass of the binder. When the addition amount is less than 50 parts by mass, a sufficient effect on glossiness may not be obtained. The upper limit of the addition amount is not particularly limited, but is preferably 90 parts by mass or less from the viewpoint of coating suitability in consideration of the fluidity of kaolin, particularly the thickening under high shear force.

Examples of the organic pigment include water-soluble dispersions such as styrene-acrylic copolymer particles, styrene-butadiene copolymer particles, polystyrene particles, and polyethylene particles. Two or more of these organic pigments may be mixed.
The addition amount of the organic pigment is preferably 2 parts by mass to 20 parts by mass with respect to 100 parts by mass of the total pigment in the ink receiving layer. Since the organic pigment is excellent in gloss expression and its specific gravity is smaller than that of the inorganic pigment, it is possible to obtain an ink receiving layer that is bulky, high gloss, and has good surface coverage. If the addition amount is less than 2 parts by mass, the above effect is not obtained. If the addition amount exceeds 20 parts by mass, the fluidity of the coating liquid is deteriorated, leading to a decrease in coating operability, and economical in terms of cost. Not right.
The organic pigment has a solid type, a hollow type, a donut type, and the like in its form, but the average particle size is 0.2 μm in view of the balance of gloss development, surface coverage, and fluidity of the coating liquid. A hollow mold having a porosity of 40% or more is more preferable.

As the binder, an aqueous resin is preferably used.
As the aqueous resin, at least one of a water-soluble resin and a water-dispersible resin is preferably used. There is no restriction | limiting in particular as said water-soluble resin, According to the objective, it can select suitably, For example, modified products of polyvinyl alcohol, such as polyvinyl alcohol, anion modified polyvinyl alcohol, cation modified polyvinyl alcohol, acetal modified polyvinyl alcohol; Polyurethane; polyvinylpyrrolidone and polyvinylpyrrolidone and vinyl acetate copolymer, vinylpyrrolidone and dimethylaminoethyl / methacrylic acid copolymer, quaternized vinylpyrrolidone / dimethylaminoethyl / methacrylic acid copolymer, vinylpyrrolidone and Modified products of polyvinylpyrrolidone such as a copolymer of methacrylamidopropyl trimethylammonium chloride; Cellulo such as carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose Modified products of cellulose such as cationized hydroxyethyl cellulose; Synthetic resins such as polyester, polyacrylic acid (ester), melamine resin, or modified products thereof, polyester and polyurethane copolymer; poly (meth) acrylic acid, Examples include poly (meth) acrylamide, oxidized starch, phosphate esterified starch, self-modified starch, cationized starch, or various modified starches, polyethylene oxide, sodium polyacrylate, and sodium alginate. These may be used individually by 1 type and may use 2 or more types together.
Among these, polyvinyl alcohol, cation-modified polyvinyl alcohol, acetal-modified polyvinyl alcohol, polyester, polyurethane, a copolymer of polyester and polyurethane, and the like are particularly preferable from the viewpoint of ink absorbability.

The water-dispersible resin is not particularly limited and may be appropriately selected depending on the intended purpose. For example, polyvinyl acetate, ethylene-vinyl acetate copolymer, polystyrene, styrene- (meth) acrylate ester copolymer Polymer, (meth) acrylic acid ester polymer, vinyl acetate- (meth) acrylic acid (ester) copolymer, styrene-butadiene copolymer, ethylene-propylene copolymer, polyvinyl ether, silicone-acrylic copolymer Coalescence, etc. Further, it may contain a crosslinking agent such as methylolated melamine, methylolated urea, methylolated hydroxypropylene urea, or isocyanate, or may be a copolymer containing units such as N-methylolacrylamide and having a self-crosslinking property. A plurality of these water-based resins can be used simultaneously.
The amount of the aqueous resin added is preferably 2 parts by mass to 100 parts by mass and more preferably 3 parts by mass to 50 parts by mass with respect to 100 parts by mass of the pigment. The amount of the aqueous resin added is determined so that the liquid absorption characteristics of the recording medium fall within a desired range.

  When a water-dispersible colorant is used as the colorant, the cationic organic compound is not necessarily added, but is not particularly limited and can be appropriately selected and used depending on the purpose. For example, a primary to tertiary amine, quaternary ammonium salt monomer or oligomer that reacts with a sulfonic acid group, a carboxyl group, an amino group, or the like in a direct dye or acidic dye in water-soluble ink to form an insoluble salt. A polymer etc. are mentioned, Among these, an oligomer or a polymer is preferable.

Examples of the cationic organic compound include dimethylamine / epichlorohydrin polycondensate, dimethylamine / ammonia / epichlorohydrin condensate, poly (trimethylaminoethyl methacrylate / methyl sulfate), diallylamine hydrochloride / acrylamide copolymer, (Diallylamine hydrochloride / sulfur dioxide), polyallylamine hydrochloride, poly (allylamine hydrochloride / diallylamine hydrochloride), acrylamide / diallylamine copolymer, polyvinylamine copolymer, dicyandiamide, dicyandiamide / ammonium chloride / urea / formaldehyde condensate , Polyalkylene polyamine dicyandiamide ammonium salt condensate, dimethyl diallyl ammonium chloride, polydiallyl methylamine hydrochloride, poly (diallyl dimethyl ester) Ruammonium chloride), poly (diallyldimethylammonium chloride / sulfur dioxide), poly (diallyldimethylammonium chloride / diallylamine hydrochloride derivative), acrylamide / diallyldimethylammonium chloride copolymer, acrylate / acrylamide / diallylamine hydrochloride copolymer Products, ethyleneimine derivatives such as polyethyleneimine and acrylicamine polymer, and polyethyleneimine alkylene oxide modified products. These may be used individually by 1 type and may use 2 or more types together.
Among these, low molecular weight cationic organic compounds such as dimethylamine / epichlorohydrin polycondensate and polyallylamine hydrochloride and other relatively high molecular weight cationic organic compounds such as poly (diallyldimethylammonium chloride) It is preferable to use in combination. The combined use improves the image density and further reduces feathering compared to the single use.

The cation equivalent of the cationic organic compound by colloid titration method (using polyvinyl potassium sulfate and toluidine blue) is preferably 3 meq / g to 8 meq / g. If the cation equivalent is within this range, good results can be obtained within the dry adhesion range.
Here, in the measurement of the cation equivalent by the colloid titration method, the cationic organic compound is diluted with distilled water so as to have a solid content of 0.1% by mass, and pH adjustment is not performed.

Dry deposit mass of the cationic organic compound is 0.3g ^{/ m 2} ~2.0g ^/ m 2 is preferred. When the dry adhesion amount of the cationic organic compound is lower than 0.3 g / m ² , sufficient image density improvement and feathering reduction effects may not be obtained.

  There is no restriction | limiting in particular as said surfactant, Although it can select suitably according to the objective, Any of an anionic active agent, a cationic active agent, an amphoteric active agent, and a nonionic active agent can be used. Of these, nonionic active agents are particularly preferred. By adding the surfactant, the water resistance of the image is improved, the image density is increased, and bleeding is improved.

Examples of the nonionic activator include higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, fatty acid ethylene oxide adducts, polyhydric alcohol fatty acid ester ethylene oxide adducts, higher aliphatic amine ethylene oxide adducts, and fatty acid amides. Ethylene oxide adduct, fat ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, fatty acid ester of glycerol, fatty acid ester of pentaerythritol, fatty acid ester of sorbitol and sorbitan, fatty acid ester of sucrose, alkyl ether of polyhydric alcohol, And fatty acid amides of alkanolamines. These may be used individually by 1 type and may use 2 or more types together.
The polyhydric alcohol is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include glycerol, trimethylolpropane, pentaerythritol, sorbitol, and sucrose. As the ethylene oxide adduct, a product obtained by substituting a part of ethylene oxide with an alkylene oxide such as propylene oxide or butylene oxide is also effective as long as water solubility can be maintained. The substitution rate is preferably 50% or less. 4-15 are preferable and, as for HLB (hydrophilic / lipophilic ratio) of the said nonionic activator, 7-13 are more preferable.

  The addition amount of the surfactant is preferably 0 part by mass to 10 parts by mass, and more preferably 0.1 part by mass to 1.0 part by mass with respect to 100 parts by mass of the cationic organic compound.

  In the ink receiving layer, other components can be added as necessary, as long as the objects and effects of the present invention are not impaired. Examples of the other components include additives such as alumina powder, pH adjuster, preservative, and antioxidant.

There is no restriction | limiting in particular as a formation method of the said ink receiving layer, According to the objective, it can select suitably, It can carry out by the method of impregnating or apply | coating an ink receiving layer liquid on the said support body. The impregnation or coating method of the ink receiving layer liquid is not particularly limited and may be appropriately selected depending on the intended purpose. For example, conventional size press, gate roll size press, film transfer size press, blade coater, rod coater It is possible to coat with various coating machines such as air knife coater and curtain coater, but from the viewpoint of cost, conventional size press, gate roll size press, film transfer size press etc. installed in paper machine It may be impregnated or deposited and finished on-machine.
Adhesion amount of the ink-receiving layer solution is not particularly limited and may be appropriately selected depending on the intended purpose, in ^{solid, 0.5g / m 2 ~20g / m} 2 are preferred, ^{1 g} / m 2 to 15 g / M ² is more preferable.
After the impregnation or coating, it may be dried as necessary. In this case, the drying temperature is not particularly limited and may be appropriately selected depending on the intended purpose. preferable.

The basis weight of the recording medium is ^preferably from ^{50g / m 2 ~250g / m 2} , 50g / m 2 ~200g / m 2 is more preferable. If the basis weight is less than 50 g / m ² , there is no stiffness, so that a conveyance failure such as a recording medium being clogged in the conveyance path is likely to occur. On the other hand, if the basis weight exceeds 250 g / m ² , the stiffness becomes too large, and the recording medium cannot be bent at the curved portion in the middle of the conveying path, and the recording medium is also jammed. Prone to occur.

  The recording medium may further include a back layer on the back surface of the support, and another layer between the support and the ink receiving layer, or between the support and the back layer, and a protective layer on the ink receiving layer. Can also be provided. Each of these layers may be a single layer or a plurality of layers.

  The recording medium having a low water absorption capability may be a commercially available coated paper for offset printing, coated paper for gravure printing, etc. in addition to the inkjet recording medium, as long as the liquid absorption property is within the range of the present invention. .

<Ink record>
The ink recorded matter used in the present invention has an image formed on the recording medium using each ink in the ink set of the present invention.
The recording medium is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include plain paper, coated paper for printing, glossy paper, special paper, cloth, film, and OHP sheet. Can be mentioned. These may be used individually by 1 type and may use 2 or more types together. Among these, at least one of plain paper and coated paper for printing is preferable.
The plain paper is advantageous in that it is inexpensive. The coated paper for printing is advantageous in that it provides a smooth glossy image at a relatively low cost as compared with glossy paper.

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

(Production Example 1)
<Preparation of aqueous dispersion of magenta polymer fine particles>
-Preparation of polymer solution A-
After sufficiently replacing the inside of a 1 L flask equipped with a mechanical stirrer, thermometer, nitrogen gas inlet tube, reflux tube, and dropping funnel, 11.2 g of styrene, 2.8 g of acrylic acid, 12.0 g of lauryl methacrylate Then, 4.0 g of polyethylene glycol methacrylate, 4.0 g of styrene macromer, and 0.4 g of mercaptoethanol were mixed and heated to 65 ° C.
Next, 100.8 g of styrene, 25.2 g of acrylic acid, 108.0 g of lauryl methacrylate, 36.0 g of polyethylene glycol methacrylate, 60.0 g of hydroxylethyl methacrylate, 36.0 g of styrene macromer, 3.6 g of mercaptoethanol, azobismethylvalero A mixed solution of 2.4 g of nitrile and 18 g of methyl ethyl ketone was dropped into the flask over 2.5 hours. After dropping, a mixed solution of 0.8 g of azobismethylvaleronitrile and 18 g of methyl ethyl ketone was dropped into the flask over 0.5 hours. After aging at 65 ° C. for 1 hour, 0.8 g of azobismethylvaleronitrile was added and further aging was performed for 1 hour. After completion of the reaction, 364 g of methyl ethyl ketone was added to the flask, and 800 g of a polymer solution A having a concentration of 50% by mass was prepared.

-Preparation of aqueous dispersion of magenta polymer fine particles-
Next, 28 g of the obtained polymer solution A, C.I. I. 42 g of CI Pigment Red 122, 13.6 g of a 1 mol / L potassium hydroxide aqueous solution, 20 g of methyl ethyl ketone, and 13.6 g of ion-exchanged water were sufficiently stirred, and then kneaded using a roll mill. The obtained paste was put into 200 g of pure water and stirred sufficiently, and then the methyl ethyl ketone and water were distilled off using an evaporator, and the magenta polymer fine particles of Production Example 1 containing 15% by mass of pigment and 20% by mass of solid were prepared. An aqueous dispersion was prepared.

(Production Example 2)
-Preparation of copper phthalocyanine pigment-containing polymer fine particle dispersion-
In Production Example 1, C.I. I. An aqueous dispersion of cyan polymer fine particles was prepared in the same manner as in Production Example 1 except that Pigment Red 122 was changed to a copper phthalocyanine pigment, and further 12% by mass of pigment and 20% by mass of solid content.

(Production Example 3)
-Preparation of monoazo yellow pigment-containing polymer fine particle dispersion-
In Production Example 1, C.I. I. An aqueous dispersion of yellow polymer fine particles was prepared in the same manner as in Production Example 1 except that Pigment Red 122 was changed to Pigment Pigment Yellow 74, and the pigment content was changed to 12 mass% and solid content 20 mass%.

(Production Example 4)
-Preparation of polymer fine particle dispersion B (acryl-silicone emulsion)-
A 1 L flask equipped with a mechanical stirrer, thermometer, nitrogen gas inlet tube, reflux tube, and dropping funnel was sufficiently replaced with nitrogen gas, and then added 8.0 g of Latemule S-180 and 350 g of ion exchange water. The temperature was raised to 65 ° C. After raising the temperature, 3.0 g of t-butyl peroxobenzoate and 1.0 g of sodium isoascorbate as reaction initiators were added, and after 5 minutes, 45 g of methyl methacrylate, 160 g of 2-ethylhexyl methacrylate, 5 g of acrylic acid, butyl methacrylate 45 g, 30 g of cyclohexyl methacrylate, 15 g of vinyltriethoxysilane, 8.0 g of Latemule S-180, and 340 g of ion-exchanged water were mixed and added dropwise over 3 hours. Then, after heat aging at 80 ° C. for 2 hours, the mixture was cooled to room temperature and the pH was adjusted to 7-8 with sodium hydroxide. Ethanol was distilled off using an evaporator and the water content was adjusted to prepare 730 g of a polymer dispersion B solution having a solid content of 40% by mass.
The particle diameter of the obtained resin fine particles was 130 nm (measured at 23 ° C.). The particle size was measured using a particle size distribution measuring device UPA150 manufactured by Microtrack Co., Ltd. at a dilution ratio of 500 times.

(Production Example 5)
-Preparation of surface-treated black pigment dispersion-
90 g of carbon black having a CTAB specific surface area of 150 m ² / g and DBP oil absorption of 100 ml / 100 g is added to 3,000 ml of 2.5N sodium sulfate solution, stirred at a temperature of 60 ° C. and a speed of 300 rpm, and reacted for 10 hours. Oxidation treatment was performed. The reaction solution was filtered, and the carbon black separated by filtration was neutralized with a sodium hydroxide solution and subjected to ultrafiltration. The obtained carbon black was washed with water, dried, and dispersed in pure water so as to have a solid content of 20% by mass to prepare a black pigment dispersion of Production Example 5.

(Production Example 6)
<Preparation of black ink 1>
First, a wetting agent, a penetrating agent, a surfactant, and water having the following ink composition were mixed and stirred uniformly for 1 hour to mix uniformly. A water-dispersible resin was added to the mixed solution and stirred for 1 hour, and a pigment dispersion, a pH adjuster and an antifoaming agent were added and stirred for 1 hour. This dispersion was subjected to pressure filtration with a cellulose acetate membrane filter having an average pore diameter of 0.8 μm to remove coarse particles and dust, thereby producing black ink 1.

-Composition of black ink 1-
-Black pigment dispersion of Production Example 5 (solid content 20% by mass) ... 40% by mass
-Polymer fine particle dispersion B of Production Example 4 13.75% by mass
・ 3-Methyl 1,3-butanediol: 17% by mass
・ Glycerin: 8.5% by mass
・ 2-Pyrrolidone: 2% by mass
・ Penetration agent (2-ethylhexanediol): 2% by mass
・ Amine pH adjuster 1 ... 0.6% by mass
-Amine-based pH adjuster 2 0.05 mass%
・ Surfactant (Zonyl FS-300, manufactured by DuPont) ... 2.5% by mass
・ Stabilizer (benzotriazole): 0.05% by mass
-Antiseptic and fungicide ... 0.2% by mass
・ Defoaming agent ... 0.1% by mass
・ Water ... Remaining amount

<Comparison between calculated and measured values of residual moisture at equilibrium>
Among the compositions of the black ink 1, the equilibrium water content calculated as the wetting agent is glycerin, 3-methyl-1,3-butanediol, and 2-pyrrolidone. The total amount of the wetting agent was 27.5% by mass, the solid content was 13.5% by mass of the resin and the pigment together, and the initial moisture content was 55% by mass.
Here, the equilibrium moisture content (Ei) of glycerin (GLY), 1,3-butanediol (13BD), 3-methyl-1,3-butanediol (MBD), 2-pyrrolidone (2-Py) as a wetting agent The humidity change is shown in FIG. FIG. 13 shows an approximate expression derived so as to pass through the origin.
Using the following approximate expression 1 between the amount of each wetting agent (Mi (%)) and the equilibrium water content Ei (%) of FIG. 13, the residual water content Wt at equilibrium at the environmental humidity was calculated (i = 1, 2, 3; 3 kinds of wetting agents).
<Approximation Formula 1>
Wt = ΣMi × Ei / (100−Ei)
In the approximate formula 1, i represents a wetting agent type, and Σ represents the sum of each wetting agent.

On the other hand, 0.5 g of black ink 1 was collected in a petri dish, left in a desiccator, and weighed when the humidity was stable, and the actually measured equilibrium water content was determined.
FIG. 14 shows the calculated value of the amount of water evaporation (%) obtained by subtracting the final amount of residual moisture at equilibrium (%) from the initial amount of water (%), and the amount of water evaporation until equilibrium obtained by actual measurement. However, both agree very well, and it has been found that the amount of water evaporation can be calculated by the above approximate expression 1 from the equilibrium water amount of each wetting agent.

(Production Example 7)
<Preparation of cyan ink 1>
First, a wetting agent, a penetrating agent, a surfactant, and water having the following ink composition were mixed and stirred uniformly for 1 hour to mix uniformly. A water-dispersible resin was added to the mixed solution and stirred for 1 hour, and a pigment dispersion, a pH adjuster and an antifoaming agent were added and stirred for 1 hour. This dispersion was subjected to pressure filtration through a cellulose acetate membrane filter having an average pore diameter of 0.8 μm to remove coarse particles and dust, and cyan ink 1 was produced.
-Composition of cyan ink 1-
-Cyan dispersion of Production Example 2 ((solid content 20% by mass) ... 42% by mass
-Polymer fine particle dispersion B of Production Example 4 8.3 mass%
・ 1,3-butanediol ... 24.4% by mass
・ Glycerin: 8.1% by mass
・ Penetration agent (2-ethylhexanediol): 2% by mass
・ Amine pH adjuster 1 ... 0.6% by mass
・ Surfactant (Zonyl FS-300, manufactured by DuPont) ... 2.5% by mass
-Antiseptic / antifungal agent ... 0.05% by mass
・ Defoaming agent ... 0.1% by mass
・ Water ... Remaining amount

Of the composition of the cyan ink 1, glycerin and 1,3-butanediol were calculated as the equilibrium moisture content as the wetting agent. The total amount of wetting agent was 32.5% by mass, the solid content was 11.7% by mass of the resin and pigment combined, and the initial moisture content was 52% by mass.
The equilibrium moisture content of each cyan ink 1 at each humidity was calculated using the relational expression between humidity and equilibrium moisture content. Subtracting this from the initial amount of water is the amount of water evaporated until the ink equilibrium, and as shown in FIG. It was.

Next, FIG. 16 shows a comparison of the calculated values of the residual moisture amount (%) at equilibrium for each humidity of the black ink 1 and the cyan ink 1.
From the results shown in FIG. 16, it was found that the black ink 1 has a smaller residual water amount at equilibrium and a larger evaporation amount than the cyan ink 1.

(Comparative Example 1)
-Preparation of ink set 1-
An ink jet printer (stock) that uses a combination of cyan ink 1 and black ink 1 as the ink set 1 and has nozzles in the same ink head and covers the ink head with the same covering means (moisturizing cap). Various characteristics were evaluated in the following manner using a laboratory improvement machine (G707, G505, manufactured by Ricoh Co., Ltd.).

<Confirmation of ejection disturbance of each ink>
Print evaluation with an inkjet printer (Ricoh Co., Ltd., G707 G505, experimental improvement machine) using black ink 1 and cyan ink 1 that have reached equilibrium after being left at a temperature of 35 ° C. and a humidity of 20% RH. did. As a result, it was found that only the black ink 1 had streaks in the image, and the ejection disorder of the black ink 1 occurred.

<Confirmation of drying time of each ink>
Using a printing paper that hardly absorbs water (Oji Paper Co., Ltd., POD gloss coat 100 g / m ² paper), black ink 1 and cyan ink 1 are improved printers for experiments using an ink jet printer (Ricoh Co., Ltd., G707 G505). ).
The transfer amount of pure water to a recording medium at a contact time of 100 ms measured with a dynamic scanning absorptivity of printing paper (manufactured by Oji Paper Co., Ltd., POD gloss coat 100 g / m ² paper) is 3.1 ml / m. ² and the transfer amount of pure water to the recording medium at a contact time of 400 ms was 3.5 ml / m ² .
When the filter paper 5A (manufactured by Advantech Co., Ltd.) is pressed against the printed image when the ink adhesion amount is 10 mg / m ² , the drying time until the ink adhesion disappears is 30 seconds for the black ink 1 On the other hand, cyan ink 1 was 40 seconds, and a difference in drying time was recognized.

<Measurement of viscosity after drying>
Using a viscoelasticity measurement apparatus (Anton Paar, Physica MCR301), viscoelasticity measurement was performed on black ink 1 and cyan ink 1 collected by 0.9 cc with a micropipette. The measurement environment was measured by installing a viscoelasticity measuring device on a drying table at 40 ° C., at a temperature of 29 ° C. and a humidity of 24% RH, at the beginning and after evaporating water for 5 minutes. The results are shown in FIG.
As a result, the initial viscosity was the same, but when the shear rate of the viscosity was compared after evaporating and drying for 5 minutes, the black ink 1 immediately after the rotation was considerably thicker than the cyan ink 1.
This is because the black ink 1 has a smaller total amount of wetting agent than the cyan ink 1 and also has a smaller estimated calculation of the residual water content at equilibrium, resulting in faster water evaporation and lower residual water content at equilibrium. This is probably because the solid content concentration at the time increased.
Thus, since cyan ink 1 is hard to evaporate, it is harder to thicken than black ink 1 and is good in ejection reliability. However, show-through due to poor drying after printing is more common in cyan ink 1. become.
The difference between the total amount of wetting agent and the amount of residual moisture at equilibrium for each ink as in the ink set of Comparative Example 1 is not preferable in terms of device design because it increases the variation between ejection reliability and drying ink.
Further, when the total amount of the wetting agent and the residual moisture amount at equilibrium are matched between the black ink 1 and the cyan ink 1 (an improved ink of the black ink 1 in which the GLY ratio of the wetting agent described later is 50%), as shown in FIG. Both tendencies are closer in the viscosity after water evaporation. In the initial stage, there is no difference with any ink.

(Experiment)
Next, in order to adjust the equilibrium moisture content of the black ink 1 to the equilibrium moisture content of the cyan ink 1, the total amount of the wetting agent of the black ink 1 is set to 32.5% by mass, which is the same as the total amount of the wetting agent of the cyan ink 1. The agent ratio was changed. Specifically, the amount of residual moisture at equilibrium was calculated by changing the ratio of GLY and MBD without changing the amount of 2-Py. The results are shown in FIGS.
From the calculation results, when the GLY ratio is 50%, the residual water amount at the time of equilibrium between the black ink 1 and the cyan ink 1 (the residual water amount per 100 parts by mass of the initial ink amount) matches. Moreover, they match at the same GLY ratio at any humidity.
<Formula 4>
GLY ratio (%) ≈GLY (mass) × 100 / ((GLY (mass) + MBD (mass))
The calculated value of the amount of residual moisture at equilibrium when the GLY ratio is changed is shown.

18 to 24, there is a description of black ink 1. In this case, the total amount of the wetting agent of black ink 1 is 32.5% by mass, and the GLY ratio is changed.
Although the wetting agent type is different between cyan ink 1 and black ink 1, the residual moisture content at equilibrium is consistent at any humidity by setting the GLY ratio of the wetting agent of black ink 1 to 50%. The reason why the same GLY ratio is consistent at any humidity in this way is thought to be because the relationship between the equilibrium moisture content of each wetting agent and the humidity is not in a completely irrelevant formula depending on the compound but has a certain correlation. It is. This was found from the results of FIG. 13 showing the relationship between the equilibrium water content and the humidity. The target of the relationship between the humidity of each wetting agent and the equilibrium moisture content is high, and if any of the wetting agents has a convex relationship, the GLY ratio at which the residual moisture content at the time of equilibrium between the two inks is the humidity Should be different. The 50% number just happens to be 50% for this combination of inks, and will be a different ratio for different wetting agent types.
As described above, even in inks of different wetting agent types, by matching the total amount of wetting agent with the amount of water remaining at equilibrium, characteristics related to moisture evaporation are close, and there are various advantages in using the ink.
Here, the black ink 1 in which the GLY ratio is 50% and the total amount of wetting agent of cyan ink and the residual moisture amount at equilibrium are combined is referred to herein as the improved ink of black ink 1 (corresponding to that in FIG. 21).
Thus, even when the equilibrium water content is adjusted with the GLY ratio set to 50%, the solid content (%) at equilibrium (EM (%)) differs between the two inks. Also, the amount of water evaporated by the time of equilibrium is different.
This is because the initial moisture content of the two inks is different. As described above, it is extremely effective to match the residual water amount at equilibrium between the inks having different initial water content and solid content.

Example 1
-Preparation of ink set 2-
A combination of cyan ink 1 and improved ink of black ink 1 (GLY ratio of 50% in FIG. 21) is used as ink set 2, nozzles are present in the same ink head, and the ink head is covered with the same cover means. Various characteristics were evaluated in the same manner as in Comparative Example 1 using an ink jet printer (an improved machine made by Ricoh Co., Ltd., G707, G505) that was covered with (moisturizing cap).

<Confirmation of ejection disturbance of each ink>
In either case, no ejection disturbance occurred in the ink. Also, because the evaporation of the cyan ink 1 and the improved ink of the black ink 1 are about the same and the solid content is also the same, the difference in the degree of deterioration when leaving the nozzle is improved compared to before the change. .

<Confirmation of drying time of each ink>
When printing with Oji Paper Co., Ltd., POD gloss coat 100 g / m ² paper as an ink jet printer (Ricoh Co., Ltd., G707, G505, experimental improvement machine) as a printing paper that hardly absorbs water, The difference in drying time between cyan ink 1 and improved ink of black ink 1 is also eliminated.

<Measurement of viscosity after drying>
When the change in viscosity due to the shear rate when each ink was dried for the same time on a 40 ° C. drying stand (humidity 20% RH) was measured, the difference in increase in viscosity between cyan ink 1 and improved ink of black ink 1 was measured. There was no.

  As in the ink set 2 of the first embodiment, by sharing the characteristics relating to the water balance, the difference in ink color such as the reliability of each ink and the drying property of the image is reduced. In the case of using a cap), either water evaporation is not increased. Furthermore, even when the moisture retaining caps are not common, it is possible to optimize the cleaning timing, the drying time after printing, and thus the printing speed.

  In addition to the combination of the improved ink of the black ink 1 and the cyan ink 1 in Example 1, the total amount of the wetting agent and the residual moisture at the time of equilibration for the magenta ink and the yellow ink are also adjusted in accordance with the prescription of the cyan ink 1. By combining the amounts, the same effect was obtained for any combination of the four color inks.

(Example 2)
<Preparation of ink set 3>
−Preparation of black ink 2−
A wetting agent, penetrant, surfactant, and water having the following ink composition were mixed, and stirred for 1 hour to be uniformly mixed. A water-dispersible resin was added to the mixed solution and stirred for 1 hour, and a pigment dispersion, a pH adjuster and an antifoaming agent were added and stirred for 1 hour. This dispersion was subjected to pressure filtration through a cellulose acetate membrane filter having an average pore diameter of 0.8 μm to remove coarse particles and dust, thereby producing black ink 2.
This black ink 2 has the same solid content and initial moisture content as the cyan ink 1 in addition to the total amount of wetting agent and the residual moisture content at equilibrium.
-Composition of black ink 2-
-Black pigment dispersion of Production Example 5 (solid content 20% by mass) ... 42% by mass
-Polymer fine particle dispersion of Production Example 4 8.3 mass%
・ 3-methyl-1,3-butanediol: 15.26% by mass
・ Glycerin ... 15.26% by mass
・ 2-Pyrrolidone: 2% by mass
・ Penetration agent (2-ethylhexanediol): 2% by mass
・ Amine pH adjuster 1 ... 0.6% by mass
-Amine-based pH adjuster 2 0.05 mass%
・ Surfactant (Zonyl FS-300, manufactured by DuPont) ... 2.5% by mass
・ Stabilizer (benzotriazole): 0.05% by mass
-Antiseptic and fungicide ... 0.2% by mass
・ Defoaming agent ... 0.1% by mass
・ Water ... Remaining amount

  In this case, the cyan ink 1 and the black ink 2 are combined with the total amount of the wetting agent and the solid content, and since the difference in the amount of the additive other than the wetting agent and the solid content is slight, the initial moisture amount is almost the same (difference) 2% or less). As a result, it was almost completely consistent with the water balance including the amount of water evaporated until equilibrium and the solid content at equilibrium (%) (EM (%)). Of course, the type and amount of wetting agent, and the type of solid content are different for both inks. The reason that the total humidity is consistent in this way seems to be because the equilibrium moisture content of each wetting agent and the humidity have a proportional relationship.

As described above, in the ink set 3 including the black ink 2 and the cyan ink 1 including a plurality of wetting agents, even if the wetting agent types and amounts of the respective inks are different, When the moisture content at equilibrium of the wetting agent is made the same and the solid content of each ink is made the same, the amount of water evaporated until equilibrium, the residual moisture content at equilibrium, and the final solid content ratio are the same (see FIG. 25). .
In addition to the total amount of wetting agent and the residual moisture amount at equilibrium, the combination of the black ink 2 and the cyan ink 1 in which the solid amount of the pigment and the resin match the initial moisture amount is balanced with the total amount of wetting agent in Example 1. Compared to the case where only the remaining moisture amount is combined, the characteristics related to moisture evaporation are closer to both inks, so the cleaning process timing and drying process timing can be shared by each head, improving reliability, It turns out that it leads to increase in printing speed.

In the ink set of the present invention, the total amount of the wetting agent of each ink and the residual moisture amount at equilibrium are matched even if the kind and amount of the wetting agent of each ink in the ink set and the solid content type are different. , Preferably, by adjusting the total solid content to the same level, the equilibrium with respect to moisture at almost all humidity is almost completely consistent, preventing nozzle omission and jet bending, which is highly reliable and less likely to cause clogging. It is suitably used for an ink jet recording method and an ink jet recording apparatus.
The ink jet recording method of the present invention can be applied to various types of recording by the ink jet recording method, and can be particularly suitably applied to, for example, an ink jet printer, a facsimile apparatus, a copying apparatus, a printer / fax / copier multifunction machine, and the like. .

FIG. 1 is a diagram illustrating an example of an ink cartridge used in the present invention. FIG. 2 is a view including a case (exterior) of the ink cartridge of FIG. FIG. 3 is a schematic explanatory view showing an example of the ink jet recording apparatus of the present invention. FIG. 4 is a schematic explanatory view showing an example of the internal structure of the ink jet recording apparatus of FIG. FIG. 5 is a schematic enlarged view showing an example of the inkjet head of the present invention. FIG. 6 is a schematic view showing a nozzle row of the inkjet head of the present invention. FIG. 7 is an exploded perspective view of the liquid supply device in the ink jet recording apparatus of the present invention. FIG. 8 is an enlarged exploded perspective view of FIG. FIG. 9 is a schematic side view of the sub tank. 10A is a schematic cross-sectional view taken along line AA in FIG. 10B is a schematic cross-sectional view taken along line AA in FIG. FIG. 11 is a top view of the maintenance unit of the inkjet printer according to the present invention. FIG. 12 is a schematic explanatory view showing an example of the maintenance unit of the ink jet printer of the present invention. FIG. 13 is a diagram showing the relationship between the equilibrium moisture content and humidity of glycerin, 1,3-butanediol, 3-methyl-1,3-butanediol, and 2-pyrrolidone. FIG. 14 is a diagram showing a calculated value of a water evaporation amount obtained by subtracting a final residual water amount at the time of equilibrium of the black ink 1 from an initial water amount, and a water evaporation amount until the equilibrium time obtained on the actual side. FIG. 15 is a diagram illustrating a calculated value of a water evaporation amount obtained by subtracting a final residual water amount at equilibrium of the cyan ink 1 from an initial water amount, and a water evaporation amount until equilibrium obtained on the actual side. FIG. 16 is a diagram showing calculated values of the residual moisture amount at equilibrium for each humidity of the black ink 1 and the cyan ink 1. FIG. 17 is a diagram illustrating the relationship between the shear rate and the viscosity of the black ink 1 and the cyan ink 1. FIG. 18 is a diagram illustrating the relationship between the humidity and the residual water amount at equilibrium for the black ink 1 having a glycerin ratio of 100% and the cyan ink 1. FIG. 19 is a diagram showing the relationship between the humidity of the black ink 1 having a glycerin ratio of 75% and the cyan ink 1 and the residual water content at equilibrium. FIG. 20 is a diagram illustrating the relationship between the humidity and the residual water amount at equilibrium between the black ink 1 having a glycerin ratio of 60% and the cyan ink 1. FIG. 21 is a diagram showing the relationship between the humidity of the black ink 1 having a glycerin ratio of 50% (improved ink of the black ink 1; Example 1) and the cyan ink 1 and the residual water content at equilibrium. FIG. 22 is a diagram showing the relationship between the humidity of the black ink 1 having a glycerin ratio of 40% and the cyan ink 1 and the residual water content at equilibrium. FIG. 23 is a diagram showing the relationship between the humidity of the black ink 1 having a glycerin ratio of 25% and the cyan ink 1 and the residual water content at equilibrium. FIG. 24 is a diagram showing the relationship between the humidity of the black ink 1 having a glycerin ratio of 0% and the cyan ink 1 and the residual water content at equilibrium. FIG. 25 is a diagram showing the relationship between the humidity of the black ink 2 and the cyan ink 1 and the solid content at equilibrium / (solid content + humectant + residual moisture).

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 (13)

In an ink set comprising a combination of two or more inks containing at least a colorant, a wetting agent, and a resin,
Each ink in the ink set includes at least one different type of wetting agent;
An ink containing at least the same amount of glycerin and 3-methyl-1,3-butanediol as the wetting agent;
And at least an ink containing at least glycerin and 1,3-butanediol as the wetting agent,
The ratio of the difference between the maximum value and the minimum value of the total amount of wetting agent in each ink to the maximum value is within 5%,
The ratio of the difference between the maximum value and the minimum value of the residual water amount at equilibrium at a temperature of 23 ° C. and a humidity of 50% RH in each ink is within 5%,
An ink set , wherein a ratio of a difference between a maximum value and a minimum value of an initial moisture amount in each ink to the maximum value is within 5% . The ink set according to claim 1 ratio ratios relative to the maximum value of the difference between the maximum value and the minimum value of the solid content including the definitive colorant and resin to the ink is within 5% or less. The ink set according to claim 1, wherein the solid content in each ink is 10% by mass to 13% by mass, respectively. The ink set according to any one of claims 1 to 3, wherein an initial water content in each ink is 44 mass% to 60 mass%. The ink set according to any one of claims 1 to 4, wherein each ink in the ink set is at least one of magenta ink, cyan ink, yellow ink, and black ink. An ink containing at least the same amount of glycerin and 3-methyl-1,3-butanediol as a wetting agent is a black ink,
The ink set according to any one of claims 1 to 5, wherein the ink containing at least glycerin and 1,3-butanediol as the wetting agent is at least one of magenta ink, cyan ink, and yellow ink. An ink media set comprising the ink set according to any one of claims 1 to 6 and a recording medium having an ink receiving layer on at least one surface of a support,
Pure water wherein the recording medium is, in the dynamic transfer amount to the recording medium of pure water at the contacting time 100ms measured by scanning absorptometer is is ^{2ml / m 2 ~35ml / m 2} , and the contact time 400ms the ink media set, wherein the amount of transferred to the recording medium is ^{3ml / m 2 ~40ml / m 2} .   An ink jet recording method comprising at least an ink flying step of recording an image by applying a stimulus to each ink of the ink set according to claim 1 and causing the ink to fly.   9. The ink jet recording method according to claim 8, wherein each ink head corresponding to each ink in the ink set is covered with the same covering means and moisturized.   The ink jet recording method according to claim 8, wherein cleaning of each ink head corresponding to each ink of the ink set is performed simultaneously.   The ink jet recording method according to claim 8, further comprising a drying step of drying an image recorded on the recording medium.   The ink jet recording method according to claim 8, wherein each ink head corresponding to each ink of the ink set is a line head.   An ink jet recording apparatus comprising at least ink flying means for recording an image by applying a stimulus to each ink of the ink set according to claim 1 and causing the ink to fly.