JP2014218005A - Inkjet recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet recording method which can achieve equivalent smoothness in both a recording area and a non-recording area and record an image having uniform glossiness as a whole.SOLUTION: An inkjet recording method comprises, in the following order, an ink discharge step of discharging an ink containing a pigment by inkjetting, a first liquid composition discharge step of discharging a first liquid composition by inkjetting, and a second liquid composition discharge step of discharging a second liquid composition by inkjetting. Each of the first liquid composition and the second liquid composition contains a block polymer having an acid value from 170 mg KOH/g to 300 mg KOH/g.

Description

  The present invention relates to an ink jet recording method.

  Conventionally, when an image is recorded on a recording medium using pigment ink, the fixing property of the image to the recording medium is not sufficient, the pigment is easily detached from the surface of the recording medium, and the glossiness of the image is sufficient. There was a problem of not. Here, “glossiness” includes the glossiness and image clarity of the entire image area. That is, “high gloss” means that both glossiness and image clarity are high.

  Patent Document 1 discloses a method of applying clear ink to the entire image area after recording. Furthermore, Patent Document 2 discloses a method for applying clear ink to the entire image area similar to Patent Document 1, and a method for varying the amount of clear ink applied to each region in accordance with the amount of pigment ink applied. It is disclosed. Specifically, the amount of clear ink applied is reduced in the region where the amount of pigment ink applied is large, and the amount of clear ink applied is increased in the region where the amount of pigment ink applied is small. Accordingly, the present invention aims to record an image having uniform gloss over the entire area including the non-recording area and the recording area.

JP 2006-272934 A JP 2010-94854 A

  With the methods described in Patent Documents 1 and 2, since clear ink is applied to both the recording area and the non-recording area, improvement in image gloss is expected. However, the penetration state of the clear ink differs between the area where the pigment ink is applied and the area where the pigment ink is not applied on the surface of the recording medium. For this reason, in these methods, since the unevenness of the entire image area is not sufficiently corrected, the glossiness of the recorded image is still insufficient. That is, even when any of the methods described in Patent Documents 1 and 2 is adopted, it is difficult to achieve high glossiness in the entire image area including the recording area and the non-recording area.

  Accordingly, an object of the present invention is to provide an ink jet recording method capable of recording an image having high glossiness in the entire area including a recording area and a non-recording area and having excellent image clarity.

  The above object is achieved by the present invention described below. That is, according to the present invention, an ink discharge step of discharging ink containing a pigment by an ink jet method, a first liquid composition discharge step of discharging a first liquid composition by an ink jet method, and a second liquid And a second liquid composition discharging step for discharging the composition by an ink jet method in this order, wherein both the first liquid composition and the second liquid composition have an acid value. An ink jet recording method (hereinafter also referred to as “first ink jet recording method”) is provided, which contains a block polymer having a viscosity of 170 mg KOH / g or more and 300 mg KOH / g or less.

  In addition, according to the present invention, an ink discharge step of discharging a pigment-containing ink by an ink jet method, a first liquid composition discharge step of discharging a liquid composition by an ink jet method, and the liquid composition by an ink jet method And a second liquid composition discharge step for discharging the liquid composition in this order, wherein the liquid composition contains a block polymer having an acid value of 170 mgKOH / g or more and 300 mgKOH / g or less. Inkjet recording method (hereinafter also referred to as “second inkjet recording method”) is provided.

  According to the present invention, it is possible to provide an ink jet recording method capable of recording an image having high glossiness in the entire area including a recording area and a non-recording area and having excellent image clarity.

It is the graph which plotted image clarity (sharpness value) with respect to the coverage (%). It is the graph which plotted image clarity (sharpness value) with respect to the time difference (sec) of a 1st liquid composition discharge process and a 2nd liquid composition discharge process.

<Inkjet recording method>
Hereinafter, the present invention will be described in detail with reference to preferred embodiments. The first ink jet recording method of the present invention includes an ink discharge process, a first liquid composition discharge process, and a second liquid composition discharge process in this order. The ink ejection process is a process of ejecting ink containing a pigment by an inkjet method. The first liquid composition discharge step is a step of discharging the first liquid composition by an inkjet method. The second liquid composition discharge step is a step of discharging the second liquid composition by an ink jet method.

  In addition, the second ink jet recording method of the present invention includes an ink discharge process, a first liquid composition discharge process, and a second liquid composition discharge process in this order. The ink ejection process is a process of ejecting ink containing a pigment by an inkjet method. The first liquid composition discharge step is a step of discharging the liquid composition by an ink jet method. The second liquid composition discharge step is a step of discharging again the liquid composition having the same composition as that discharged in the first liquid composition discharge step by the ink jet method.

  In the ink jet recording method of the present invention, after ink such as color ink is ejected and applied to a recording medium, a liquid composition such as clear ink containing a specific block polymer is ejected onto the recording medium in two steps. It has a feature in the point to give. In the first liquid composition discharge step, a film is formed in a region where it is desired to obtain gloss on the image surface, and the penetration rate of the liquid composition into the recording medium is made uniform. In the second liquid composition discharge step, the clear ink is applied again to the region to which the liquid composition has been applied in the first liquid composition discharge step, and the surface of the image region is smoothed.

  In the first liquid composition discharge step, a liquid composition such as clear ink is discharged to a region where it is desired to obtain gloss on the image surface, and is applied without a gap. Since a specific block polymer is contained in the liquid composition, when the applied liquid composition is osmotically dried and fixed, a film is formed in an area where gloss is desired on the image surface. However, since unevenness may occur on the surface of the formed film in accordance with the uneven penetration of the liquid composition, the glossiness of the entire image area is difficult to improve only by the first liquid composition ejection step. Resins such as a soluble resin contained in clear ink or the like do not form large particles as in the case of pigments, so that there are almost no pores and a film that hardly penetrates the solution is formed. When the formed film covers a region where it is desired to obtain gloss on the image surface, the permeation rate of the liquid composition in this region is uniformly reduced, and the permeation unevenness is almost eliminated. As described above, the first liquid composition discharge step serves to prevent the occurrence of uneven penetration of the liquid composition in a region where it is desired to obtain gloss on the image surface.

  In the first liquid composition discharge step, it is preferable to apply the liquid composition without any gap. This is because when the gap is generated, unevenness is likely to occur in the penetration rate of the liquid composition. However, a slight gap may exist to some extent. Specifically, it is preferable to apply the liquid composition so that an area of 80% or more of the region where the gloss on the image surface is desired to be coated is substantially evenly covered. “Substantially equal” means a state in which there is no significant deviation in the distribution of gaps, and specifically means that the standard deviation σ of coverage measured at 10 locations is 10% or less. A graph plotting the image clarity (sharpness value) against the coverage (%) is shown in FIG. Note that a method for measuring a sharpness value, which is an index of image clarity, and a method for forming an image (a method for producing a recorded matter) will be described in detail in “Examples”. In the example shown in FIG. 1, a trade name “PFC-103BK” (manufactured by Canon) is used as the pigment ink, and a recorded matter recorded at a duty of 75% is used. As shown in FIG. 1, it is apparent that the sharpness value is remarkably increased and the image clarity is improved by setting the coverage to 80% or more. That is, even if unevenness occurs in a gap of less than about 20%, the gloss can be remarkably improved if an area of 80% or more can be covered.

  An optical microscope can be used to measure the coverage. First, the surface of the recorded matter after application of the liquid composition is photographed by observing with an optical microscope. Specifically, an image made infinite by an optical microscope equipped with a 10 × objective lens is photographed using a digital camera with 1.2 million pixels. As an optical microscope, for example, the trade name “BX60M” manufactured by Olympus can be used. As a digital camera, a trade name “MAGNAFIRE” (MODEL 60800) manufactured by Optronics can be used. Note that there is no problem with other products as long as the devices have equivalent performance. Since a film is formed on the portion covered with the liquid composition, the color appears to change due to thin film interference. Next, the color changed by thin film interference and the color not changed are divided into two areas by image processing software or the like, and the area of each area is calculated, and the area ratio of the area corresponding to the color changed by thin film interference is calculated. Can be the coverage of the liquid composition.

  In the second liquid composition discharge step, the liquid composition is discharged and applied in the first liquid composition discharge step, and the liquid composition is further discharged and applied to a region where the uneven penetration of the liquid composition is eliminated. . The surface of the liquid composition (interface between the liquid composition and air) tends to become a smoother surface due to the surface tension of the liquid composition. Since there is no permeation unevenness of the liquid composition, the block polymer contained in the liquid composition is also affected by the surface tension and moves in a direction to make the surface of the liquid composition smoother. As a result, both the unevenness originally present on the surface of the recording medium and the unevenness formed by the first liquid composition discharging step are leveled. Thereby, the same smoothness is realized in both the recording area and the non-recording area, and an image having uniform gloss is recorded as a whole.

  When performing the second liquid composition discharge step, it is preferable that the liquid composition discharged in the first liquid composition discharge step is formed into a film. Film formation of the liquid composition proceeds when the solvent contained in the liquid composition penetrates into the recording medium or is dried. For this reason, the film formation time varies depending on the material, ink, and recording medium contained in the liquid composition. Furthermore, depending on the device configuration and material, it is preferable to provide an appropriate time between the first liquid composition discharge step and the second liquid composition discharge step. The time required for forming the film can be grasped, for example, by adjusting the time difference between the first liquid composition discharge step and the second liquid composition discharge step and measuring the change in image clarity. FIG. 2 is a graph plotting the image clarity (sharpness value) against the time difference (sec) between the first liquid composition discharge step and the second liquid composition discharge step. In the example shown in FIG. 2, the trade name “PFC-101C” (manufactured by Canon) is used as the pigment ink, and a recorded matter recorded at a duty of 150% is used. As shown in FIG. 2, it can be seen that the image clarity is remarkably improved when the interval between the first liquid composition discharge step and the second liquid composition discharge step is about 20 seconds or longer.

  Each of the first liquid composition discharge step and the second liquid composition discharge step may be performed a plurality of times. For example, depending on the material used for the liquid composition, it may be assumed that the film formed is thin by only ejecting the liquid composition once and the effect of reducing permeation unevenness is small. In such a case, it is preferable to perform the first liquid composition discharge step a plurality of times. Similarly, it may be assumed that a slight unevenness remains on the image surface when the liquid composition is discharged once. In such a case, it is preferable to perform the second liquid composition discharge step a plurality of times.

“Duty” refers to a value calculated by the following equation. In the following formula, “number of actual printing dots” is the number of actual printing dots per unit area. Further, “the number of vertical pixels” and “the number of horizontal pixels” are the number of vertical pixels and the number of horizontal pixels per unit area, respectively.
Duty (%) = {actual printing dot number / (vertical pixel number × horizontal pixel number)} × 100

  The acid value of the block polymer contained in the liquid composition is 170 mgKOH / g or more and 300 mgKOH / g or less, preferably 200 mgKOH / g or more and 290 mgKOH / g or less, more preferably 240 mgKOH / g or more and 280 mgKOH / g or less. Block polymers are known to self-assemble particles in water. However, if the acid value of the block polymer is more than 300 mgKOH / g, it is highly water-soluble, and thus deposits on the recording area but penetrates into the non-recording area. This makes it difficult to form a film over the entire image area. On the other hand, when the acid value of the block polymer is less than 170 mgKOH / g, the block polymer is excessively aggregated during the second liquid composition discharging step. For this reason, the surface of the film becomes rough, and the glossiness of the image is not improved.

  Moreover, it is preferable that the liquid composition used in the first liquid composition discharge step and the liquid composition used in the second liquid composition discharge step are the same. Thereby, the production line of the liquid composition can be reduced, the recording apparatus can be downsized, and the cost including consumables can be reduced.

<Ink>
The ink used in the ink jet recording method of the present invention contains a pigment. The ink usually further contains a resin, an organic solvent, a surfactant, water, and the like as components other than the pigment.

(Pigment)
The kind of pigment is not particularly limited. Examples of commercially available black, cyan, magenta, and yellow pigments that can be used in the ink used in the inkjet recording method of the present invention are shown below.

  The black pigments have the following trade names: Raven 1060, Raven 1080, Raven 1170, Raven 1200, Raven 1250, Raven 1255, Raven 1500, Raven 2000, Raven 3500, Raven 5250, Raven 5750, Raven 7000, Raven 5000, U Black Pearls L, MOGUL-L, Regal 400R, Regal 660R, Regal 330R, Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1300, Monarch 1400 (manufactured by Cabot); Color Bl ack FW1, Color Black FW2, Color Black FW200, Color Black 18, Decoder V 140, Color Black S170, Color Black S170, Special Black 4P, Special Black 4P, Special Black 4P, Special Black 4P, Special Black 4P No. 25, no. 33, no. 40, no. 47, no. 52, no. 900, no. 2300, no. 2600, MCF-88, MA600, MA7, MA8, MA100 (manufactured by Mitsubishi Chemical) and the like.

  Examples of cyan pigments include C.I. I. Pigment Blue-1, C.I. I. Pigment Blue-2, C.I. I. Pigment Blue-3, C.I. I. Pigment Blue-15, C.I. I. Pigment Blue-15: 2, C.I. I. Pigment Blue-15: 3, C.I. I. Pigment Blue-15: 4, C.I. I. Pigment Blue-16, C.I. I. Pigment Blue-22, C.I. I. And CI Pigment Blue-60.

  Examples of magenta pigments include C.I. I. Pigment Red-5, C.I. I. Pigment Red-7, C.I. I. Pigment Red-12, C.I. I. Pigment Red-48, C.I. I. Pigment Red-48: 1, C.I. I. Pigment Red-57, C.I. I. Pigment Red-112, C.I. I. Pigment Red-122, C.I. I. Pigment Red-123, C.I. I. Pigment Red-146, C.I. I. Pigment Red-168, C.I. I. Pigment Red-184, C.I. I. Pigment Red-202, C.I. I. Pigment Red-207 and the like.

  Examples of yellow pigments include C.I. I. Pigment Yellow-12, C.I. I. Pigment Yellow-13, C.I. I. Pigment Yellow-14, C.I. I. Pigment Yellow-16, C.I. I. Pigment Yellow-17, C.I. I. Pigment Yellow-74, C.I. I. Pigment Yellow-83, C.I. I. Pigment Yellow-93, C.I. I. Pigment Yellow-95, C.I. I. Pigment Yellow-97, C.I. I. Pigment Yellow-98, C.I. I. Pigment Yellow-114, C.I. I. Pigment Yellow-128, C.I. I. Pigment Yellow-129, C.I. I. Pigment Yellow-151, C.I. I. Pigment Yellow-154 and the like.

(resin)
As the resin, either an anionic resin or a cationic resin can be used. In particular, it is preferable to use an anionic resin. As an anionic resin, the resin containing the structural unit derived from the hydrophobic monomer, the structural unit derived from the anionic monomer, its salt, etc. can be mentioned. Specific examples of the hydrophobic monomer include methacrylic acid alkyl esters such as styrene, vinyl naphthalene and methyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethoxyethyl methacrylate, methacrylonitrile, 2-trimethylsiloxyethyl methacrylate, glycidyl methacrylate, p. -Acrylic acid alkyl esters such as tolyl methacrylate, sorbyl methacrylate, methyl acrylate, phenyl acrylate, benzyl acrylate, acrylonitrile, 2-trimethylsiloxyethyl acrylate, glycidyl acrylate, p-tolyl acrylate, and sorbyl acrylate .

  Specific examples of the anionic monomer include acrylic acid, methacrylic acid, maleic acid and the like. In consideration of the dispersion stability of the resin, nonionic components such as ethylene oxide may be copolymerized.

  The resin may be any of a block copolymer, a random copolymer, a graft copolymer, and a salt thereof. Examples of the salt include alkali metal salts such as sodium, lithium, and potassium, ammonium salts, alkylamine salts, alkanolamine salts, and the like.

(Organic solvent)
A water-soluble organic solvent is preferably used as the organic solvent contained in the ink. Specific examples of the water-soluble organic solvent include 1 to 5 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, and n-pentanol. Alkyl alcohols; amides such as dimethylformamide and dimethylacetamide; ketones or ketoalcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, Oxyethylene or oxypropylene polymers such as tripropylene glycol, polyethylene glycol, polypropylene glycol; ethylene glycol, propylene glycol Alkylene glycols in which the alkylene group contains 2 to 6 carbon atoms, such as trimethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,2-hexanediol; 1,2,6-hexane Triols such as triol, glycerin, trimethylolpropane; lower alkyl ethers of glycols such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol monomethyl (or ethyl) ether, triethylene glycol monomethyl (or ethyl, butyl) ether; Lower dialkyl ethers of polyhydric alcohols such as ethylene glycol dimethyl (or ethyl) ether and tetraethylene glycol dimethyl (or ethyl) ether; monoethanolamine, diethanolamine, triethanol Alkanolamines such as ruamine; sulfolane, N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, urea, ethylene urea, bishydroxyethyl sulfone, diglycerin, triglycerin, etc. Can be mentioned. Of these, ethylene glycol, 1,2-hexanediol, glycerin, diglycerin, polyethylene glycol, ethylene urea, and trimethylolpropane are preferable. The content of the water-soluble organic solvent is not particularly limited, but is preferably 3% by mass or more and 60% by mass or less, and more preferably 5% by mass or more and 50% by mass or less with respect to the total amount of the ink.

(Surfactant)
As the surfactant contained in the ink, it is preferable to use an acetylene glycol surfactant. By using an acetylene glycol surfactant, it is possible to improve the wettability of the recording surface such as a recording medium and the ink permeability. The content of the surfactant is preferably 0.5% by mass or more and 10% by mass or less, and more preferably 1% by mass or more and 5% by mass or less with respect to the total amount of the ink.

  Specific examples of the acetylene glycol surfactant include 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, , 5-dimethyl-1-hexyn-3-ol, 2,4-dimethyl-5-hexyn-3-ol, and the like. Commercially available acetylene glycol surfactants can also be used. Commercially available acetylene glycol surfactants include the following trade names: Olphine E1010, STG, Y (above, manufactured by Nissin Chemical); Surfynol 104, 82, 465, 485, TG (above, Air Products and Chemicals Inc.) Etc.).

<Liquid composition>
The first liquid composition and the second liquid composition used in the first ink jet recording method of the present invention and the liquid composition used in the second ink jet recording method of the present invention are substantially both. It is preferable that the clear ink does not contain a color material. The liquid composition contains a block polymer. The liquid composition usually further contains an organic solvent, a surfactant, ion-exchanged water, and the like as components other than the block polymer.

(Block polymer)
The block polymer comprises a hydrophobic segment containing a structural unit derived from a hydrophobic monomer arranged at one polymerization terminal, and a hydrophilic segment containing a structural unit derived from a hydrophilic monomer arranged at the other polymerization terminal. It is preferable to have. More specifically, an AB block polymer included in the following classification (a), an ABC block polymer included in the classification (b), and the like can be used. These block polymers include a hydrophilic segment having a carboxy group (including a hydroxy group) and a hydrophobic segment having no carboxy group (including a hydroxy group). In addition, it is preferable that each segment which comprises these block polymers is a homopolymer.

Classification (a): AB block copolymer A segment: styrene homopolymer or benzyl methacrylate homopolymer B segment: acrylic acid homopolymer or methacrylic acid homopolymer

Classification (b): ABC block copolymer A segment: styrene homopolymer or benzyl methacrylate homopolymer B segment: butyl acrylate homopolymer or butyl methacrylate homopolymer C segment: acrylic acid homopolymer or methacrylic acid homopolymer

  The block polymer may be one in which a block portion and a random portion are mixed in the molecule, or one that is not bipolarized into a hydrophilic portion and a hydrophobic portion. However, an AB block polymer included in the classification (a) is preferable from the viewpoint that the polymer components are uniformly oriented. The A segment is preferably a styrene homopolymer, and the B segment is preferably an acrylic acid homopolymer.

  The B segment in the ABC block polymer included in the classification (b) is appropriately introduced into the polymer chain in order to adjust physical properties such as the glass transition temperature (Tg) of the block polymer. As the monomer constituting the B segment, (meth) acrylic acid esters are preferable, and (meth) acrylic acid esters having an alkyl group having 4 to 6 carbon atoms are more preferable. In addition, among the ABC block polymers included in the classification (b), the A / B // C block copolymer in which the segment on the hydrophobic part side is randomly copolymerized is divided into a hydrophilic part and a hydrophobic part. Can be used. In “A / B // C”, “/” means random copolymerization, and “//” means block copolymerization.

  Said block polymer is compoundable according to the well-known method described in Unexamined-Japanese-Patent No. 6-157754 etc., for example. In the present invention, the term “hydrophilic” means a property that has a high affinity for water and can be dissolved in water alone. The term “hydrophobic” means a property that has a low affinity for water and does not dissolve in water alone.

  Specific examples of the counter ion such as a carboxy group in the hydrophilic segment of the block polymer include a hydrogen cation, a lithium cation, a sodium cation, a potassium cation, a calcium cation, and an ammonium cation.

(Organic solvent)
As the organic solvent contained in the liquid composition, a water-soluble organic solvent is preferably used. Specific examples of the water-soluble organic solvent include 1 to 5 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, and n-pentanol. Alkyl alcohols; amides such as dimethylformamide and dimethylacetamide; ketones or ketoalcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, Oxyethylene or oxypropylene polymers such as tripropylene glycol, polyethylene glycol, polypropylene glycol; ethylene glycol, propylene glycol Alkylene glycols in which the alkylene group contains 2 to 6 carbon atoms, such as trimethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,2-hexanediol; 1,2,6-hexane Triols such as triol, glycerin, trimethylolpropane; lower alkyl ethers of glycols such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol monomethyl (or ethyl) ether, triethylene glycol monomethyl (or ethyl, butyl) ether; Lower dialkyl ethers of polyhydric alcohols such as ethylene glycol dimethyl (or ethyl) ether and tetraethylene glycol dimethyl (or ethyl) ether; monoethanolamine, diethanolamine, triethanol Alkanolamines such as ruamine; sulfolane, N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, urea, ethylene urea, bishydroxyethyl sulfone, diglycerin, triglycerin, etc. Can be mentioned. Of these, ethylene glycol, 1,2-hexanediol, glycerin, diglycerin, polyethylene glycol, ethylene urea, and trimethylolpropane are preferable. The content of the water-soluble organic solvent is not particularly limited, but is preferably 3% by mass or more and 60% by mass or less, and more preferably 5% by mass or more and 50% by mass or less with respect to the total amount of the ink.

(Surfactant)
The liquid composition preferably contains at least one of an acetylene glycol surfactant and a polysiloxane surfactant. By using an acetylene glycol-based surfactant or a polysiloxane-based surfactant, the wettability of the recording surface such as a recording medium can be improved and the ink permeability can be increased. The content of the surfactant is preferably 0.5% by mass or more and 10% by mass or less, and more preferably 1% by mass or more and 5% by mass or less with respect to the total amount of the liquid composition.

  Specific examples of the acetylene glycol surfactant include 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, , 5-dimethyl-1-hexyn-3-ol, 2,4-dimethyl-5-hexyn-3-ol, and the like. Commercially available acetylene glycol surfactants can also be used. Commercially available acetylene glycol surfactants include the following trade names: Olphine E1010, STG, Y (above, manufactured by Nissin Chemical); Surfynol 104, 82, 465, 485, TG (above, Air Products and Chemicals Inc.) Etc.).

  Examples of commercially available polysiloxane surfactants include BYK-333, BYK-347, BYK-348 (manufactured by BYK Japan) and the like under the following trade names. Note that BYK-333 and BYK-348 contain polyether-modified polydimethylsiloxane as a main component. BYK-347 contains polyether-modified siloxane.

  Next, the present invention will be described more specifically with reference to examples and comparative examples. In the following description, “parts” and “%” are based on mass unless otherwise specified.

<Acid value measuring method>
A sample solution for measurement was prepared by dissolving 2 g of polymer in a mixture of 200 mL of THF and 100 mL of ethanol. The prepared sample liquid for measurement was subjected to neutralization titration in accordance with JIS K0070 using a KOH / ethanol solution having been subjected to normality measurement, and the acid value of the polymer was measured.

<Preparation of liquid composition (clear ink)>
Polymers V1 to V5, glycerin, surfactant, and ion-exchanged water were mixed in the formulation shown in Table 1 and stirred. KOH was added to adjust the pH to 9.5, and then passed through a glass filter (trade name “AP20”, manufactured by Millipore) to obtain liquid compositions C1 to C5. Polymers V1 to V5 are all styrene-acrylic acid copolymers. Polymer V1 is a random copolymer. Polymers V2, V4 and V5 are A / B // C block copolymers which are classified according to the classification method of monomer species of classification (b) described above. In addition, the polymer V3 is an AB block copolymer classified according to the classification method of the monomer type of classification (a) described above. The weight average molecular weights of the polymers used were polymer V1: 8.8 × 10 ³ , polymer V2: 1.1 × 10 ⁴ , polymer V3: 1.4 × 10 ⁴ , polymer V4: 1.1 × 10 ^{4, respectively.} Polymer V5: 1.3 × 10 ⁴ .

<Image formation>
(Examples 1-3, Comparative Examples 1-3)
The red ink chamber and the green ink chamber of an inkjet printer (trade name “iPF5100”, manufactured by Canon Inc.) were filled with the liquid composition in the combinations shown in Tables 2-1 and 2-2, respectively. The ink chambers other than those described above were filled with the color inks shown below.
Yellow: Trade name “PFI-101M” (Canon)
Magenta: Trade name “PFI-101Y” (Canon)
Cyan: Product name “PFI-101C” (Canon)

  Using the printer described above, a yellow ink, a magenta ink, or a cyan ink is recorded on a recording medium (trade name “Premium Gloss” so that the print duty is 5% (low duty portion) and 75% (high duty portion), respectively. Paper ", manufactured by Canon Inc.) and printed. In addition, two-color mixed printing was performed by applying each ink to a recording medium using a combination of yellow ink and magenta ink (red), yellow ink and cyan ink (green), and magenta ink and cyan ink (blue). The printing duty was 8% (low duty part) and 120% (high duty part), and each ink was applied to the recording medium, and the ejection amount of each ink was the same. Specifically, in 120% duty red printing, the yellow ink has a 60% duty and the magenta ink has a 60% duty, and the volume of each ink drop is 4.8 pL.

  Each pattern was printed in an area of 50 mm × 50 mm, and “clean” mode was selected with a printer driver. After the colored layer was formed, the paper was discarded, and then the paper was fed again, and then the first liquid composition was applied to the entire image so as to be 50% duty in one pass and overcoated. After overcoating, the paper was discarded, and then the paper was fed again and overcoated by applying the second liquid composition so that the entire image had a 50% duty in one pass.

(Comparative Example 4)
After the colored layer is formed, the first liquid composition and the second liquid composition are not divided into two steps, but are applied to the entire image at the same time so as to be 100% duty in one pass, and are overcoated. Formed an image in the same manner as in Example 1 described above.

(Comparative Example 5)
An image was formed in the same manner as in Example 1 except that the second liquid composition was not applied.

<Evaluation of printed matter>
(Glossy)
Using a gloss meter (trade name “GMX-203”, manufactured by Murakami Color Research Laboratory), the 20 ° gloss of each duty of each color was measured. Then, the glossiness of the printed matter was evaluated according to the evaluation criteria shown below from the measured minimum glossiness of the colored region (high duty portion) and the non-colored region (low duty portion). The results are shown in Tables 2-1 and 2-2.
◎◎: Minimum glossiness of 80 or more ◎: Minimum glossiness of 75 or more and less than 80 ○○: Minimum glossiness of 70 or more and less than 75 ○: Minimum glossiness of 60 or more and less than 70 ×: Minimum glossiness of less than 60

(Image clarity)
Using DOI Image Analysis System (trade name “DIAS”, manufactured by QEA), the sharpness value of each duty of each color was measured. Then, the image clarity of the printed matter was evaluated from the minimum sharpness values of the measured colored region (high duty portion) and non-colored region (low duty portion) according to the following evaluation criteria. The sharpness value is defined as follows. The above system uses a white LED as a light source, and has a knife edge between the light source and the measurement sample. Then, a reflection image of the knife edge reflected in the sample is taken with a CCD camera (300,000 pixels: 5 μm per pixel). Here, the pixel field of view is 2.4 mm square. The luminance distribution of the knife edge portion of the captured reflection image is first-order differentiated, and the reciprocal of the half-value width is defined as “sharpness value”. That is, the larger the sharpness value, the higher the image clarity.
◎: Minimum sharpness value is 5.0 or more ◎: Minimum sharpness value is 4.5 or more and less than 5.0 ○○: Minimum sharpness value is 4.0 or more and less than 4.5 ○: Minimum sharpness value is 3.0 or more Less than 4.0 ×: Minimum sharpness value is less than 3.0

Claims (3)

An ink ejection process for ejecting ink containing a pigment by an inkjet system, a first liquid composition ejection process for ejecting a first liquid composition by an inkjet system, and a second liquid composition by an inkjet system A second liquid composition discharge step and an inkjet recording method in this order,
The ink jet recording method, wherein each of the first liquid composition and the second liquid composition contains a block polymer having an acid value of 170 mgKOH / g or more and 300 mgKOH / g or less. An ink discharge step of discharging ink containing a pigment by an ink jet method, a first liquid composition discharge step of discharging a liquid composition by an ink jet method, and a second liquid composition of discharging the liquid composition by an ink jet method An ink jet recording method having an object ejection step in this order,
The inkjet recording method, wherein the liquid composition contains a block polymer having an acid value of 170 mgKOH / g or more and 300 mgKOH / g or less.   The block polymer has a hydrophobic segment containing a structural unit derived from a hydrophobic monomer arranged at one polymerization terminal, and a hydrophilic segment containing a structural unit derived from a hydrophilic monomer arranged at the other polymerization terminal; The ink jet recording method according to claim 1, comprising:

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