JP2007136819A - Inkjet recording head, inkjet recording device, and inkjet recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording head capable of recording high quality images by sufficiently exhibiting the characteristic of a pigment ink and reducing the non-ejection of the pigment ink from nozzles, an inkjet recording device and an inkjet recording method. <P>SOLUTION: When the pigment ink strongest in the strength of an aggregate formed upon contacting with a reaction liquid is a cyan pigment ink c1, the cyan pigment ink c1 is ejected through the nozzle arrays 104 not adjacent to the nozzle arrays 101 which eject the reaction liquid s1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording head capable of discharging a plurality of different pigment inks and a liquid for aggregating pigments contained in the pigment ink, an ink jet recording apparatus using the ink jet recording head, and an ink jet recording method. The liquid for aggregating the pigment is also referred to as a reaction liquid below.

  The ink jet recording method uses an ink jet recording head capable of ejecting ink (recording liquid) droplets, ejects ink droplets from the recording head, and causes the ink droplets to adhere to a recording medium such as paper. Is what you do.

  In such an ink jet recording method, a method for adhering a liquid for improving the image recording property onto a recording medium prior to the ejection of ink droplets has been proposed.

  For example, Patent Document 1 discloses a method of recording an ink containing an anionic dye after attaching a liquid having a basic polymer. Patent Document 2 discloses a recording method in which a first liquid containing a reactive chemical species and a liquid containing a compound that reacts with the reactive chemical species are mixed on a recording medium. Patent Document 3 discloses a method of recording an ink containing an anionic dye after adhering a liquid containing an organic compound having two or more cationic groups per molecule. Patent Document 4 discloses a method of recording an ink containing an anionic dye after adhering an acidic liquid containing succinic acid or the like. Further, Patent Documents 5 and 6 disclose a method of applying a liquid that insolubilizes a dye prior to ink recording.

  In any of the above methods, the bleeding of the image and the water resistance are improved by folding the dye itself.

  Further, Patent Document 7 proposes to prevent bleeding by utilizing a reaction between a polyvalent metal ion and a carboxyl group. In this case as well, the recording medium is impregnated with a liquid containing polyvalent metal ions, and then reacted with a colored ink to precipitate an anionic dye, thereby suppressing image bleeding and improving water resistance. It is about to try. Patent Document 8 proposes to improve bleeding by the reaction of a pigment, a resin emulsion, and a polyvalent metal salt, and the basic concept is almost the same as that proposed in Patent Document 7. The same.

  As described above, heretofore, proposals have been made to improve the color developability of a recorded matter by depositing a color material by contacting with a reaction solution.

  However, on the other hand, there is a risk that reaction liquid, mist, etc. that bounces off the surface of the recording medium after ink ejection will adhere to the face surface (formation surface of the ink ejection port) of the recording head. In this case, there is a possibility that the coloring material is deposited or aggregated from the ink adhering to the face surface, and is fixed to cause non-ejection of the ink. Therefore, unnecessary ink droplets and foreign matters adhering to the face surface are removed by wiping the face surface with a blade formed of an elastic member such as rubber. Ink thickeners, deposits, and aggregates that cause ink non-ejection are discharged from the ink ejection port to the outside by a suction pump, and a recovery process is performed to restore the ink ejection state normally. .

  However, there is a possibility that aggregates formed by contact of the pigment ink and the reaction liquid cannot be completely removed only by the above method.

  Therefore, in Patent Document 9, the positional relationship between the nozzle for discharging the reaction liquid and the nozzle for discharging a plurality of dye inks is specified, and the dye ink having high cohesion when contacting the reaction liquid is discharged. Proposals have been made to dispose the nozzles away from the reaction liquid discharge nozzles. By this proposal, it becomes possible to reduce the non-ejection of the ink in the ink jet recording head and improve the reliability of the recording head.

Japanese Unexamined Patent Publication No. 63-60783 Japanese Patent Laid-Open No. 63-22681 JP-A 63-299971 Japanese Unexamined Patent Publication No. 64-9279 JP-A-64-63185 JP-A 64-69381 JP-A-5-202328 JP-A-9-207424 JP 2000-141713 A Japanese Patent Laid-Open No. 4-10940 JP-A-4-10941 JP-A-4-10942 JP 7-214783 A Journal of Imaging Science and Technology Vol.42, No.1, Jan / Feb. 1998 (pp 49-62)

  However, Patent Document 9 considers the case of using a dye ink as an ink, but does not particularly consider the case of using a pigment ink as an ink.

  An object of the present invention is to provide an inkjet recording head, an inkjet recording apparatus, and an inkjet recording head capable of fully exhibiting the characteristics of pigment ink to enable high-quality image recording and reduce non-ejection of pigment ink from a nozzle, and It is to provide an ink jet recording method.

  As a result of intensive studies by the applicant, in order to improve the black character quality of the recorded matter, the cohesiveness of the black pigment ink is improved, and the nozzle row for discharging the black pigment ink is as close as possible to the nozzle row for discharging the reaction liquid. I found it better to place it. However, on the other hand, the ratio of the nozzle not discharging due to the aggregate generated by the contact between the pigment ink and the reaction liquid is that the distance of the nozzle line for discharging the pigment ink from the nozzle for discharging the reaction liquid is large. It turned out that it decreases as it becomes. Here, the aggregate is a solid produced by the contact between the pigment ink and the reaction liquid. This solid material is composed of a pigment ink component such as a pigment or a resin component, and a reaction liquid component such as a polyvalent metal ion in the reaction liquid. When the pigment ink comes into contact with the polyvalent metal ions in the reaction liquid, the repulsive force between the pigment particles that has been dispersed in the pigment ink is lost. Then, van der Waals attraction works between the pigment particles, and agglomerates are formed by physically adhering the pigment particles, the resins, or the pigment particles and the resin. At this time, it is considered that the aggregate agglomerates have different strengths depending on the chemical and physical properties of the pigment such as pigment type and pigment surface shape, and the chemical and physical properties of the resin such as the chemical composition and molecular weight of the resin. It is done.

  Further, when recording is performed on the dedicated paper using pigment ink, the color image may have a particularly low glossiness and a deterioration in image quality. The special paper is usually mixed with a cationic compound, and conventionally, high color development has been realized by reducing the bleeding of the dye ink that used an anionic dye. When an image is recorded on such special paper using pigment ink containing pigment fine particles generally dispersed by an anion resin, the pigment fine particles form aggregates on the special paper. Due to the agglomerates, the surface of the recording part becomes uneven, and the smoothness of the paper surface in the recording part and the non-recording part becomes non-uniform, which may reduce the glossiness of the image. Therefore, in order to improve the gloss on the special paper, it is necessary to reduce the aggregation reaction. On the other hand, if this agglomeration reaction is too weak, the color developability on a recording paper containing no or a small amount of a cation compound such as plain paper is lowered for the same reason as the above-mentioned black character quality. In order to record high-quality color images on various recording papers, in consideration of such agglomeration, a nozzle array for discharging pigment ink and a nozzle array for discharging reaction liquid are arranged on the recording head. Therefore, it is necessary to appropriately adjust the cohesiveness of the pigment ink on the recording paper.

  The inkjet recording head of the present invention is the inkjet recording head in which a plurality of nozzle arrays for discharging a plurality of different pigment inks and a liquid that aggregates the pigments contained in the pigment inks are arranged. Among the inks, the nozzle row that discharges the pigment ink having the strongest strength of the pigment aggregate formed by contact with the liquid is arranged at a position that is not adjacent to the nozzle row that discharges the reaction liquid. Features.

  The ink jet recording apparatus of the present invention uses a plurality of nozzle rows for discharging a plurality of different pigment inks and a nozzle row for discharging a liquid that agglomerates the pigment contained in the pigment ink. In the ink jet recording apparatus for recording an image, among the plurality of pigment inks, the pigment ink having the strongest strength of the aggregate of pigments formed by contact with the liquid is not adjacent to the nozzle row that discharges the liquid. The ink is discharged from a predetermined nozzle row.

  The inkjet recording method of the present invention uses a plurality of nozzle rows for ejecting a plurality of different pigment inks and a nozzle row for ejecting a liquid that agglomerates the pigment contained in the pigment ink. In the inkjet recording method for recording an image, among the plurality of pigment inks, the pigment ink having the highest strength of the aggregate of pigments formed by contact with the liquid is not adjacent to the nozzle row that discharges the liquid. It is characterized by discharging from the nozzle row.

  According to the present invention, the pigment ink having the strongest strength of the pigment aggregate formed by contact with the reaction liquid is discharged from the nozzle row that is not adjacent to the nozzle row that discharges the reaction liquid. Non-ejection of pigment ink can be reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, the basic configuration of the embodiment of the present invention will be described.
[Basic configuration]
In the ink jet recording head of the present invention, a plurality of types of pigment inks containing at least a pigment, a resin, a water-soluble solvent, and water, and a liquid (reaction liquid) for aggregating the pigments contained in these pigment inks A nozzle row group is formed. The nozzle row that discharges the pigment ink with the strongest strength (aggregate strength) of the pigment aggregate formed when the pigment ink and the reaction liquid are mixed is located at a position other than the position adjacent to the nozzle row for reaction liquid ejection. Is done. Various methods can be considered as a method for adjusting the aggregate strength. For example, the strength can be adjusted by a dispersion resin used to disperse the pigment or a resin added to the pigment ink. In this case, it is preferable because a desired aggregate strength can be set by selecting a functional group to be introduced into the resin.

  FIGS. 1A and 1B are explanatory diagrams of different configuration examples of an ink jet recording head used in a serial scan type ink jet recording head described later.

  In these examples, nozzle rows S for discharging a reaction liquid, which will be described later, and nozzle rows C1, C2, C3, and C4 for discharging pigment ink are formed. An ink flow path is formed between each nozzle row and an ink cartridge (not shown) so that the pigment ink and the reaction liquid corresponding to these nozzle rows are supplied. In each nozzle row, nozzle holes (discharge ports) 5 for discharging the reaction liquid and the pigment ink are arranged. Among the plurality of pigment inks, the pigment ink having the strongest strength of the aggregate produced when mixed with the reaction liquid is supplied so as to be discharged from a nozzle row other than the nozzle row adjacent to the nozzle row S for discharging the reaction liquid. To do. That is, in the case of FIG. 1 (a), the pigment ink having the strongest aggregate formed when the reaction liquid is mixed is supplied so as to be ejected from nozzle rows C2, C3, or C4 that are not adjacent to the nozzle row S. To do. In the case of FIG. 1B, the pigment ink having the strongest aggregate formed when the reaction liquid is mixed is supplied so as to be ejected from the nozzle row C4 not adjacent to the nozzle row S.

  1A and 1B, each nozzle row is represented by a straight line, but a plurality of nozzle holes 5 are arranged in each nozzle row as enlarged to the left side in FIG. 1A. . In FIG. 1A, nozzle holes 5 of the same size are formed in a line at regular intervals along the sub-scanning direction indicated by the arrow Y. However, the nozzle holes may have different diameters, and may be formed in a plurality of rows within one nozzle row. Further, the nozzle holes 5 do not need to be arranged at equal intervals in the nozzle row, and need not be arranged linearly. Further, the nozzle rows S for discharging the reaction liquid and the nozzle rows C1, C2, C3, and C4 for discharging the pigment ink may have different lengths as shown in FIG. 1B, for example. Further, all of the nozzle rows C1, C2, C3, and C4 for discharging the pigment ink may not have a length. Further, in FIG. 1A, all the nozzle rows are formed at equal intervals in the main scanning direction of the arrow X, but these intervals can be arbitrarily set as required.

  Since the recording head shown in FIGS. 1A and 1B has four nozzle rows for discharging pigment ink, it is possible to discharge four colors of pigment ink. However, the number of colors of the pigment ink to be ejected is not limited to four colors, it is possible to arrange nozzle rows for a desired number of colors, and there are a plurality of nozzle rows to which pigment inks of the same color are supplied. May be.

  In addition, among the plurality of pigment inks, the pigment ink having the weakest aggregate strength generated when mixed with the reaction liquid is supplied so as to be discharged from the nozzle row adjacent to the nozzle row S for discharging the reaction liquid. Is preferred. In this case, the agglomerates generated by the contact between the reaction liquid and the pigment ink can be easily removed by wiping and recovery operations described later even if they block the nozzle holes.

  The ink discharge mechanism in the ink jet recording head may be any means as described in Non-Patent Document 1, for example. For example, ink can be ejected using an electrothermal transducer (heater) or pressure generating means (piezo element or the like). Hereinafter, an ink jet recording head that ejects ink using an electrothermal transducer will be described.

  FIGS. 2A and 2B are explanatory diagrams of an ink ejection method using an electrothermal converter that can be suitably used in the present invention, and are referred to as a communication ejection method. 2 (a) and 2 (b) are explanatory views of the principle of the continuous discharge method based on the premise that the electrothermal converter (thermal energy generating means) and the nozzle hole (discharge port) face each other.

  FIG. 2A is a cross-sectional view of a main part of the ink jet recording head. In the figure, a heating resistance layer (thermal energy supply means) 2 as an electrothermal converter is provided on a substrate 1. An orifice plate OP mounted on the substrate 1 forms a liquid path B that is connected to the ink common liquid chamber C and bends, and a nozzle hole (discharge port) 5. The heating resistance layer 2 and the nozzle hole 5 face each other.

  The heating resistance layer 2 is supplied with an electrode signal (pulse signal) corresponding to a recording signal, thereby causing a rapid temperature rise (300) that causes film boiling in the ink (shown with diagonal lines) in the liquid path B. C. or higher) is generated in a short time, and bubbles 6 are generated. The bubble 6 grows and pushes the ink in the thickness portion of the orifice plate OP, and dilutes the ink in that portion. Thereafter, the bubbles 6 communicate with the atmosphere (outside air) in the nozzle hole vicinity region A2 in the outside air side periphery A1 of the nozzle hole 5. According to such a communication state, a stable ink droplet 7 as shown by a broken line in FIG. 2A is generated in the nozzle hole without splashing and without generating a mist-like ink droplet. 5 can be discharged from the center. At this time, since the growth of the bubbles 6 does not block the liquid path B, the ink that does not need to go in the ejection direction can remain as an aggregate continuous with the ink in the liquid path B.

  As a result, it is possible to stabilize the discharge amount of the ink droplet 7 and the discharge speed. Moreover, the bubble 6 can be rapidly and reliably generated in the vicinity of the nozzle hole 5 by utilizing a stabilization region of 300 ° C. or more among the film boiling. Therefore, in combination with the refill property of the liquid passage B that is in the non-blocking state, highly stable and high-speed recording can be achieved.

  Such a recording head can be realized by the configuration and the manufacturing method described in Patent Document 10, Patent Document 11, and Patent Document 12. More specifically, for example, it can be suitably produced by the method described in Patent Document 12.

  As the pigment ink, an ink containing at least a pigment, a resin, a water-soluble solvent, and water can be suitably used. In the pigment ink, the pigment is used in a range of 1 to 20% by weight, preferably 2 to 12% by weight, based on the total weight of the pigment ink. Specific examples of black, yellow, magenta, and cyan pigments to be used are given below.

(Black pigment)
Examples of the black pigment include carbon black. For example, carbon black produced by a furnace method or a channel method, having a primary particle diameter of 15 to 40 mμ (nm), a specific surface area by a BET method of 50 to 400 m ² / g, and a volatile content of 0.5 to 10% Those having a pH value of 2 to 10 are preferable. Examples of commercially available pigments having such properties include No. 2300, no. 900, MCF88, No. 33, no. 40, no. 45, no. 52, MA7, MA8, no. There is 2200B (manufactured by Mitsubishi Chemical). Also, there are RAVEN 1255 (above, Colombia), REGAL 400R, REGAL 330R, REGAL 660R, MOGUL L (above Cabot). Further, there are Color Black FW1, Color Black FW18, Color Black S170, Color Black S160, Printex 35, Printex U (manufactured by Degussa). Any commercially available product can be preferably used.

  When the aggregate strength of the black pigment ink is adjusted to be the highest among the pigment inks of a plurality of colors, the recording quality can be improved mainly by improving the reflection density of characters recorded by the black pigment ink. Therefore, it is preferable. That is, when the black pigment ink comes into contact with the reaction liquid on the recording paper, aggregates are formed on the paper surface, and the penetration of the coloring material into the paper surface is suppressed.

(Yellow pigment)
Examples of yellow pigments include C.I. I. Pigment Yellow 1, C.I. I. Pigment Yellow 2, C.I. I. Pigment Yellow 3, C.I. I. Pigment Yellow 13 can be mentioned. Furthermore, C.I. I. Pigment Yellow 16, C.I. I. Pigment Yellow 74, C.I. I. Pigment Yellow 83. In addition, C.I. I. Pigment Yellow 109, C.I. I. Pigment Yellow 128 etc. can also be mentioned.

(Magenta pigment)
Examples of magenta pigments include C.I. I. Pigment Red 5, C.I. I. Pigment Red 7 is available. In addition, C.I. I. Pigment Red 12, C.I. I. Pigment Red 48 (Ca), C.I. I. There is also Pigment Red 48 (Mn). Furthermore, C.I. I. Pigment Red 57 (Ca), C.I. I. Pigment Red 57: 1, C.I. I. Pigment Red 112, C.I. I. Pigment Red 122, quinacridone solid solution, and the like.

(Cyan pigment)
Examples of cyan pigments include C.I. I. Pigment Blue 1, C.I. I. Pigment Blue 2, C.I. I. And CI Pigment Blue 3. In addition, C.I. I. Pigment Blue 15: 3, C.I. I. Also available is Pigment Blue 15: 4. Furthermore, C.I. I. Pigment Blue 16, C.I. I. Pigment Blue 22, C.I. I. Vat Blue 4, C.I. I. Vat Blue 6 etc. can be mentioned.

  The present invention is not limited to these pigments. In addition to the above, it is of course possible to use a newly produced pigment such as a self-dispersing pigment.

  Further, in order to improve the image quality (particularly glossiness) of the color pigment ink, it is better to reduce the cohesiveness than the black pigment ink. Furthermore, considering the color developability of a color image on plain paper, the color having higher lightness has less influence on the color developability due to the cohesiveness. Therefore, the color having higher lightness may reduce the cohesiveness.

  In addition to highly cohesive black pigment ink (high cohesiveness) to improve recording quality on plain paper, black with reduced cohesiveness to improve image quality (especially gloss) on special paper A pigment ink (low aggregation) may be provided separately. In this case, the black pigment ink (low aggregation) may be ejected from the head adjacent to the reaction liquid because of the low aggregation even though it is black pigment ink.

  In addition, the resin contained in the pigment ink preferably has a weight average molecular weight in the range of 1,000 to 30,000, more preferably in the range of 3,000 to 15,000. Specific examples of such resins include styrene, styrene derivatives, vinyl naphthalene, vinyl naphthalene derivatives, and aliphatic alcohol esters of α, β-ethylenically unsaturated carboxylic acids. Moreover, vinyl compounds having an acidic functional group such as (meth) acrylic acid, maleic acid, itaconic acid, fumaric acid, vinyl sulfonic acid, and vinyl phosphonic acid can be given. Furthermore, (meth) acrylic acid derivatives, maleic acid derivatives, itaconic acid derivatives, fumaric acid derivatives, vinyl acetate, vinylpyrrolidone and acrylamide can be mentioned. Further, a copolymer comprising at least one or two or more monomers selected from the above resins and derivatives thereof (of which at least one is a hydrophilic polymerizable monomer), or these And the like. Alternatively, natural resins such as rosin, shellac and starch can be preferably used. These resins are preferably contained in the range of 0.1 to 5% by weight with respect to the total weight of the color pigment ink. Further, these resins may be used as the above-described pigment dispersion resin.

  The aggregate strength can also be adjusted by adding a resin that is dissolved and dispersed in the pigment ink in addition to the dispersion resin as described above. At this time, the resin added to the pigment ink can improve the aggregate strength when the hydrophilicity is lowered.

  In particular, in the case of a colored pigment ink containing a pigment as described above, the entire colored pigment ink is preferably adjusted to be neutral or alkaline. By adjusting in this way, the solubility of the resin used as the pigment dispersant in the ink can be improved, and a colored pigment ink that is more excellent in long-term storage can be obtained. However, in this case, since it may cause corrosion of various members used in the ink jet recording apparatus, it is preferable that the pH range is 7-10. Examples of pH adjusters used in this case include various organic amines such as diethanolamine and triethanolamine, inorganic alkali agents such as alkali metal hydroxides such as sodium hydroxide, lithium hydroxide and potassium hydroxide, Examples include organic acids and mineral acids. The pigments and resins as described above are dispersed or dissolved in an aqueous liquid medium.

  In addition, it is preferable to use ion-exchanged water (deionized water) as water suitable for the colored pigment ink containing such a pigment, not general water containing various ions.

  Moreover, the following can be mention | raise | lifted as a water-soluble solvent used by mixing with water. Examples thereof include alkyl alcohols having 1 to 4 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, and tert-butyl alcohol. Alternatively, amides such as dimethylformamide and dimethylacetamide; ketones or ketoalcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane. Alternatively, polyalkylene glycols such as polyethylene glycol and polypropylene glycol. Alternatively, alkylene glycols in which the alkylene group contains 2 to 6 carbon atoms. These are ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, 1,2-hexanediol, diethylene glycol and the like. Or glycerin. Alternatively, lower alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol methyl (or ethyl) ether, and triethylene glycol monomethyl (or ethyl) ether. Alternatively, N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone and the like can be mentioned. Among these many water-soluble organic solvents, polyhydric alcohols such as diethylene glycol and lower alkyl ethers of polyhydric alcohols such as triethylene glycol monomethyl (or ethyl) ether are preferred.

  The content of such a water-soluble solvent in the pigment ink is generally 3 to 50% by weight, more preferably 3 to 40% by weight, based on the total weight of the pigment ink. The water content used is 10 to 90% by weight, preferably 30 to 80% by weight, based on the total weight of the pigment ink.

  Further, as the pigment ink, in addition to the above components, a surfactant, an antifoaming agent, a preservative, and the like can be appropriately added in order to obtain a pigment ink having desired physical properties as necessary. . As an example of the addition amount, 0.05 to 10% by weight, preferably 0.5 to 5% by weight is suitable. As examples of the anionic surfactant, any commonly used ones such as a carboxylate type, a sulfate type, a sulfonate type, and a phosphate type can be preferably used.

  As a method for producing the pigment ink as described above, first, a pigment is added to an aqueous medium in which at least a resin as a dispersant and water are mixed, and the mixture is stirred. Then, it disperses using the dispersion | distribution means mentioned later, and performs a centrifugal separation process as needed, and obtains a desired dispersion liquid. Next, an appropriately selected water-soluble solvent or additive component as mentioned above is added to this dispersion and stirred to obtain a pigment ink.

  In addition, when using resin which has an acidic functional group as mentioned above as a dispersing agent, if a base is added in order to dissolve resin, dispersion stability will improve. As bases at that time, organic amines such as monoethanolamine, diethanolamine, triethanolamine, aminemethylpropanol and ammonia, or inorganic bases such as potassium hydroxide and sodium hydroxide are preferably used.

  In addition, in the method for producing the pigment ink, it is effective to perform premixing before stirring and dispersing the aqueous medium containing the pigment. That is, such a premixing operation is preferable because it can improve the wettability of the pigment surface and promote the adsorption of the dispersant to the pigment surface.

  The disperser used in the pigment dispersion treatment as described above may be any disperser that is generally used. Examples thereof include a ball mill, a roll mill, a sand mill, and a nanomizer (trade name). Among these, a high-speed sand mill can be preferably used. Examples of such a mill include a super mill, a sand grinder, a bead mill, an agitator mill, a glen mill, a dyno mill, a pearl mill, and a cobol mill (all are trade names).

  In addition, in an ink jet recording method using a colored pigment ink containing a pigment, a pigment having an optimum particle size distribution is used because of a demand for clogging resistance to prevent nozzle clogging. As a method for obtaining a pigment having a desired particle size distribution, various methods can be exemplified. For example, reduce the size of the grinding media of the disperser, increase the filling rate of the grinding media, increase the processing time, slow the discharge speed, and classify with a filter or centrifuge after grinding. , And combinations of these methods.

(Reaction solution)
Any reaction liquid may be used as long as it can agglomerate solid components such as pigments and resins dispersed in the pigment ink as described above, and can be solid-liquid separated from the pigment ink. The most suitable reactive agent is a polyvalent metal salt. The polyvalent metal salt is composed of a divalent or higher polyvalent metal ion and an anion that binds to the polyvalent metal ion. Specific examples of polyvalent metal ions include divalent metal ions such as Ca ²⁺ , Cu ²⁺ , Ni ²⁺ , Mg ²⁺ and Zn ²⁺ , and trivalent metal ions such as Fe ³⁺ and Al ³⁺ Can be given. Examples of the anion include Cl ⁻ , NO ₃ ⁻ , SO ₄ ^{2− and the} like. In order to form an aggregate by reacting instantaneously, it is desirable that the total charge concentration of polyvalent metal ions in the reaction solution is at least twice the total charge concentration of reverse polarity ions in the color pigment ink.

  Examples of the water-soluble organic solvent that can be used in the reaction solution include amides such as dimethylformamide and dimethylacetamide, ketones such as acetone, and ethers such as tetrahydrofuran and dioxane. Moreover, polyalkylene glycols, such as polyethylene glycol and polypropylene glycol, can be mentioned. Further, alkylene glycols such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, diethylene glycol and the like can be mentioned. Furthermore, lower alkyl ethers of polyhydric alcohols such as ethylene glycol methyl ether, diethylene glycol monomethyl ether, and triethylene glycol monomethyl ether can be exemplified. Moreover, monohydric alcohols, such as ethanol, isopropyl alcohol, n-butyl alcohol, and isobutyl alcohol, can be mentioned. Other examples include glycerin, N-methyl-2-pyrrolidone, 1,3-dimethyl-imidazolidinone, triethanolamine, sulfolane, dimethyl sulfoxide, and the like.

  Although there is no restriction | limiting in particular about content of the water-soluble organic solvent in a reaction liquid, 5-60 weight% of the reaction liquid whole weight, More preferably, 5-40 weight% is a suitable range.

  Further, the reaction solution may further contain additives such as a viscosity adjuster, a pH adjuster, a preservative, and an antioxidant as necessary, but it may contain a surfactant that functions as a penetration enhancer. Care should be taken in selecting and adding the amount to suppress the permeability of the reaction liquid to the recording medium. Further, the reaction liquid is more preferably colorless, but it may be a light color in a range that does not change the color tone of each color ink when mixed with ink on the recording medium. Furthermore, as a preferable range of various physical properties of the reaction solution as described above, the viscosity at around 25 ° C. is 1 to 30 cps. What was adjusted so that it might become the range of this is preferable.

[First Embodiment]
Next, a first embodiment of the present invention based on the basic configuration described above will be described. In the following description, “part” and “%” are based on weight unless otherwise specified.

In the present embodiment, the reaction liquid s1 was prepared as follows.
<Preparation of reaction solution s1>
-Diethylene glycol 10.0 parts-Methyl alcohol 5.0 parts-Magnesium nitrate 10.0 parts-Acetylenol E100 (manufactured by Kawaken Fine Chemicals) 0.1 part-Ion-exchanged water 74.9 parts

  As the black pigment ink k1, a commercially available inkjet pigment ink BJI-P705BK200 (manufactured by Canon Inc.) was used. In addition, BJI-P705C (manufactured by Canon) was used as the an-pigment ink c1, BJI-P705M (made by Canon) was used as the magenta pigment ink m1, and BJI-P705Y (made by Canon) was used as the yellow pigment ink y1.

  Aggregate strength generated when the pigment inks k1, c1, m1, and y1 of the respective colors come into contact with the reaction liquid s1 was evaluated as follows.

  First, 5 μl of the reaction liquid s1 was injected into a 10 ml sample bottle, and further 5 μl of the pigment ink k1 was injected into the sample bottle so as to be in contact with the reaction liquid s1, thereby generating agglomerated aggregates. Subsequently, 10 ml of ion-exchanged water was injected into the sample bottle, a stirrer chip was introduced, and the rotation speed was 500 rpm. For 2 minutes. By this stirring, the aggregate was broken into a lump shape and became a fine granular shape. The size of the granular aggregates was measured with a laser diffraction particle size distribution analyzer (SALD-3100, manufactured by Shimadzu Corporation). It is considered that the higher the aggregate strength, the smaller the aggregate collapse and the larger the diameter. Similarly, the size of the granular aggregate of the pigment inks c1, m1, and y1 was measured. Table 1 below shows the measurement results for k1, c1, m1, and y1.

  FIG. 3 is a schematic configuration diagram of the ink jet recording head according to the present embodiment, and five nozzle rows 101, 102, 103, 104, and 105 are formed as in FIG. 1A described above. These nozzle rows 101, 102, 103, 104, and 105 are supplied so as to eject the reaction liquid S1, the yellow pigment ink y1, the black pigment ink k1, the cyan pigment ink c1, and the magenta pigment ink m1.

  The reaction liquid s1 is discharged from the nozzle row 101, and the cyan pigment ink c1 having the highest aggregate strength is discharged from the nozzle row 104. The yellow pigment ink y1 is ejected from the nozzle array 102, the black pigment ink k1 is ejected from the nozzle array 103, and the magenta pigment ink m1 is ejected from the nozzle array 105.

  Recording was performed by mounting such a recording head 10 in a recording apparatus as shown in FIG. In FIG. 4, for convenience of explanation, each of the nozzle arrays 101, 102, 103, 104, and 105 is shown as constituting an individual recording head.

  The recording apparatus includes a carriage 12 on which such a recording head can be mounted, a flexible cable 13 for sending an electric signal from the recording apparatus main body to the recording head, a cap unit 14 having recovery means, and the like. Further, a paper feed tray 18 for feeding a recording member (recording paper or the like) 17 is provided. The cap unit 14 includes cap members 501, 502, 503, 504, and 505 corresponding to the nozzle rows 101, 102, 103, 104, and 105, and wiper blades 601, 102, 103, and 104 made of rubber and the like, 105. The wiper blade 601 corresponds to the nozzle row 101, and the wiper blades 102, 103, 104, and 105 correspond to the nozzle rows 102, 103, 104, and 105, respectively.

  In the recording apparatus having such a configuration, the recording head having the nozzle rows 101, 102, 103, 104, and 105 intersects with the carriage 12 and the conveyance direction Y (sub-scanning direction) of the recording medium 17 (in this example, It can be moved in the direction of the arrow X (in the main scanning direction) B (perpendicular). While moving the recording head in the main scanning direction, ink is ejected from the nozzle holes in the nozzle rows, thereby recording in a region having a width corresponding to the length of the nozzle rows. When recording by one scanning of the recording head (recording for one band) is completed, the recording medium 17 is conveyed in the sub-scanning direction by an amount substantially equal to the recording width (band width). Images are sequentially recorded on the recording medium 17 by repeating such recording scanning and the conveying operation of the recording medium 17.

  In the nozzle rows 101, 102, 103, 106, 105, 104, for example, 256 nozzle holes are formed at a density of 600 nozzles per inch (600 dpi), and about 20 ng of processing liquid or Ink can be ejected. In this case, the recording density in the sub-scanning direction is 600 dpi (dots / inch), and accordingly, the recording density in the main scanning direction is also 600 dpi.

  By using the reaction liquid s1, the black pigment ink k1, the cyan pigment ink c1, the magenta pigment ink m1, and the yellow pigment ink y1, the recording apparatus equipped with such a recording head is used to produce PB paper (manufactured by Canon) that is plain paper. Images were recorded. Bleeding between the ink colors did not occur, and the recording quality of plain paper was good. Table 2 below shows the evaluation results of the recording quality of the recording portion by each ink color. The evaluation results show the results of measuring the reflection density for the black pigment ink and the saturation for the color pigment ink (c1, m1, y1,) with a reflection densitometer RD-19I (manufactured by GretagMacbeth).

  In such recording results, the color developability on plain paper was good.

  Further, an image was recorded on a commercially available photo glossy paper (PR-101: manufactured by Canon Inc.) using the above-described recording apparatus. The recorded matter produced by such recording had natural gloss. As for the glossiness of the image, a glossiness meter (VG-2000: manufactured by Nippon Denshoku Industries Co., Ltd.) was used, and the 20-degree gloss value was measured at any 10 points for each recorded portion of each ink color. Table 3 below shows the average glossiness in the recording portion for each ink color.

  Next, 100 sheets of PB paper (manufactured by Canon), which is plain paper, each using one of the black pigment ink k1, the cyan pigment ink c1, the magenta pigment ink m1, and the yellow pigment ink y1 and the reaction liquid s1. Images were recorded. After producing a recorded material by such recording, the surface of the recording head on which the nozzle array was formed was observed. As a result, no adhesion of aggregates was observed on the surface, and nozzle clogging did not occur.

  As described above, in this embodiment, the nozzle row for discharging the pigment ink having the highest aggregate strength with the reaction liquid (in this example, the cyan pigment ink) is adjacent to the nozzle row for discharging the reaction liquid. A recording head arranged at a position not to be used was used. As a result, nozzle clogging could be reduced, and a recorded matter with high recording quality could be produced using both plain paper and special paper.

[Second Embodiment]
In the ink jet recording head according to the present embodiment, the nozzle row for discharging the pigment ink having the lowest aggregate strength is arranged close to the nozzle row for discharging the reaction liquid.

  When recording an image, the reaction liquid and the pigment ink used were the same reaction liquid s1, black pigment ink k1, cyan pigment ink c1, magenta pigment ink m1, and yellow pigment ink y1 as in the first embodiment. The recording apparatus is the same as that of the first embodiment, and the reaction liquid s1, the pigment inks k1, c1, m1, and y1 are associated with the nozzle arrays 101, 102, 103, 104, and 105 as follows.

  That is, as shown in FIG. 5, the reaction liquid s <b> 1 is discharged from the nozzle row 101, and the magenta pigment ink m <b> 1 having the weakest aggregate strength is discharged from the nozzle row 102 adjacent to the nozzle row 101. The yellow pigment ink y1 is ejected from the nozzle array 103, the cyan pigment ink c1 is ejected from the nozzle array 104, and the black pigment ink k1 is ejected from the nozzle array 105.

  By using a recording apparatus using such a recording head, an image was recorded on plain paper to create a recorded matter, and the reflection density and saturation of each ink color portion were measured as in the first embodiment.

  With respect to the magenta pigment ink m1 having the weakest aggregate strength, the optical density on plain paper could be improved by discharging it from the nozzle row 102 adjacent to the nozzle row 101 for discharging the reaction liquid s1.

  Next, a recorded matter in which an image was recorded on dedicated paper was prepared, and the glossiness of the recorded portion for each ink color was measured. The measurement method is the same as in the first embodiment.

  By discharging the magenta pigment ink m1 having the weakest aggregate strength from the nozzle row 102 adjacent to the nozzle row 101 for discharging the reaction liquid s1, the glossiness variation between the inks is reduced and the glossiness of the entire image is reduced. I was able to improve.

  Next, 100 sheets of PB paper (manufactured by Canon), which is plain paper, using any one of black pigment ink k1, cyan pigment ink c1, magenta pigment ink m1, yellow pigment ink y1 and reaction liquid s1. An image was recorded. After producing the recorded material in this way, the surface of the recording head on which the nozzle array was formed was observed. No adhesion of aggregates was observed on the surface, and nozzle clogging did not occur.

[Third embodiment]
This embodiment is a corresponding example when the black pigment ink is the ink having the highest aggregate strength.

  As the reaction solution, the same reaction solution s1 as in the first embodiment was used, and as the black pigment ink k2, ICBk31 (manufactured by Seiko Epson Corporation) was used. The cyan pigment ink c2 was ICC31 (manufactured by Seiko Epson), the magenta pigment ink m2 was ICM31 (manufactured by Seiko Epson), and the yellow pigment ink y2 was ICY31 (manufactured by Seiko Epson). The aggregate strength of each pigment ink generated by contacting with the reaction liquid s1 is as follows.

  The recording apparatus is the same as that of the first embodiment. The reaction liquid s1 and the pigment inks k2, c2, m2, and y2 are the nozzle arrays 101, 102, 103, 104, and 105, and the nozzle arrays 101, 102, and 105, respectively. 103, 104, and 105 are associated in the same manner as in FIG.

  That is, the reaction liquid s1 is discharged from the nozzle row 101, and the black pigment ink k2 having the strongest aggregate strength is discharged from the nozzle row 105. The cyan pigment ink c2 is ejected from the nozzle row 102, the magenta pigment ink m2 is ejected from the nozzle row 103, and the yellow pigment ink y1 is ejected from the nozzle row 104.

  Using the recording apparatus, as in the first embodiment, the reflection density and the saturation of a recorded matter produced by recording an image on plain paper were measured.

  By using the black pigment ink k2 as the ink having the highest aggregate strength, the optical density of the recorded matter produced using the black pigment ink on plain paper is improved, and the character quality produced using the black pigment ink is high. It becomes possible to create a recorded matter.

  Next, the glossiness of the recorded matter in which the image was recorded on the special paper was measured. The measurement method is the same as in the first embodiment.

  Even when the ink having the highest aggregate strength was the black pigment ink k2, there was little variation in the glossiness between the inks, and the glossiness of the entire image was not deteriorated.

Next, using one of the black pigment ink k2, the cyan pigment ink c2, the magenta pigment ink m2, and the yellow pigment ink y2 and the reaction liquid s1, 100 sheets of PB paper (manufactured by Canon), which is plain paper, are used. Images were recorded one by one to produce recorded matter. Then, after the recordings were produced, the state of adhesion of aggregates on the surface of the recording head on which the nozzle rows were formed was observed. As a result, adhesion of aggregates was not observed and nozzle clogging did not occur.
[Fourth Embodiment]
The ink jet recording head in this embodiment has a plurality of nozzle arrays for discharging a reaction liquid.

  As shown in FIG. 7, the recording head 11 of this example includes nozzle rows 101 for discharging a reaction liquid at both ends, and nozzles for discharging pigment ink so as to be sandwiched between the two nozzle rows 101 and 101. A total of 6 columns 102, 103, 104, and 105 are arranged. In such a recording head 11, nozzle rows for discharging a plurality of types of pigment inks are arranged in contrast, and in the ink jet recording apparatus, either in the forward direction or the return direction (X1 and X2 directions) in the main scanning direction X. Even when scanned, a good image can be recorded. That is, regardless of whether the recording head 11 is scanned in the forward direction or the backward direction (X1 and X2 directions), the landing order of the plurality of types of pigment inks on the recording paper is the same, and the color change due to the difference is changed. Can be eliminated.

  In such a recording head 11, the same reaction liquid s1, black pigment ink k2, cyan pigment ink c2, magenta pigment ink m2, and yellow pigment ink y2 as those in the third embodiment are used as shown in FIG. Are associated with nozzle rows. In this example, the nozzle row 101 that discharges the reaction liquid s1 is arranged at both ends, and the nozzle row 102 near the end of the total of 6 rows of nozzle rows 102, 103, 104, and 105 that discharge pigment ink reacts. Adjacent to the nozzle row 101 for discharging liquid. In addition, the closer the nozzle row (104, 105) to the center, the farther the nozzle row from the nozzle row 101 for discharging the reaction liquid. The black pigment ink k2 having the highest aggregate strength is discharged from the nozzle row 105 which is a nozzle row other than the nozzle row 102 adjacent to the nozzle row 101 for discharging the reaction liquid.

  Recording was performed by mounting such a recording head 11 on the same recording apparatus as in the first embodiment. Note that the configuration of the cap member, the wiper blade, and the like is changed so that the nozzle row is increased as compared with the first embodiment, so that the cap member and the wiper blade can be appropriately handled.

  Using the recording apparatus, as in the first embodiment, the reflection density and the saturation of a recorded matter produced by recording an image on plain paper were measured.

  By using the black pigment ink k2 as the ink with the highest aggregate strength, the reflection density of the printed matter produced using the black pigment ink on plain paper is improved, and the printed matter with high character quality using the black pigment ink. Can be created.

  Next, the glossiness of the recorded matter in which the image was recorded on the special paper was measured. The measurement method is the same as in the first embodiment.

  Even when the ink having the highest aggregate strength was the black pigment ink k2, there was little variation in the glossiness between the inks, and there was no decrease in the glossiness of the entire image.

  Next, using one of the black pigment ink k2, the cyan pigment ink c2, the magenta pigment ink m2, and the yellow pigment ink y2 and the reaction liquid s1, 100 sheets of PB paper (manufactured by Canon), which is plain paper, are used. Images were recorded one by one to produce recorded matter. Then, after the recordings were produced, the state of adhesion of aggregates on the surface of the recording head on which the nozzle rows were formed was observed. As a result, adhesion of aggregates was not observed and nozzle clogging did not occur.

[Fifth Embodiment]
In the ink jet recording head according to this embodiment, the nozzle array for discharging the reaction liquid is disposed so as to be sandwiched between the nozzle arrays for discharging the pigment ink.

  As shown in FIG. 8, the recording head 16 of this example has a nozzle row 101 for discharging a reaction liquid arranged in the center, and nozzle rows 102, 103, 104 for discharging pigment ink so as to sandwich the nozzle row. , 105 are arranged in a total of 8 rows. Similar to the fourth embodiment, such a recording head 16 records a good image when the ink jet recording apparatus is scanned in either the forward path or the backward path (X1 and X2 directions) in the main scanning direction X. can do. That is, regardless of whether the recording head 16 is scanned in the forward direction or the backward direction (X1 and X2 directions), the landing order of the plurality of types of pigment inks on the recording paper is the same, and the color change due to the difference is changed. Can be eliminated.

  In such a recording head 16, the same reaction liquid s1, black pigment ink k2, cyan pigment ink c2, magenta pigment ink m2, and yellow pigment ink y2 as in the third embodiment are used, as shown in FIG. Corresponding to the nozzle row. The nozzle row 101 that discharges the reaction liquid s1 is arranged in the center, and the nozzle rows 102, 103, 104, and 105 for discharging the pigment ink are adjacent to the nozzle row 101 for discharging the reaction liquid. It becomes a nozzle row to do. A nozzle row farther from the center (104 or 105) is a nozzle row farther from the nozzle row 101 for discharging the reaction liquid. The black pigment ink k2 having the highest aggregate strength is discharged from the nozzle row 105 which is a nozzle row other than the nozzle row 102 adjacent to the nozzle row 101 for discharging the reaction liquid.

  Such a recording head 16 was mounted on a recording apparatus similar to that of the first embodiment to perform recording. Note that the configuration of the cap member, the wiper blade, and the like is changed so that the nozzle row is increased as compared with the first embodiment, so that the cap member and the wiper blade can be appropriately handled.

  Using the recording apparatus, as in the first embodiment, the reflection density and the saturation of a recorded matter produced by recording an image on plain paper were measured.

  By using the black pigment ink k2 as the ink with the highest aggregate strength, the reflection density of the printed matter produced using the black pigment ink on plain paper is improved, and the printed matter with high character quality using the black pigment ink. Can be created.

  Next, the glossiness of the recorded matter in which the image was recorded on the special paper was measured. The measurement method is the same as in the first embodiment.

  Even when the ink having the highest aggregate strength was the black pigment ink k2, there was little variation in the glossiness between the inks, and there was no decrease in the glossiness of the entire image.

  Next, using one of the black pigment ink k2, the cyan pigment ink c2, the magenta pigment ink m2, and the yellow pigment ink y2 and the reaction liquid s1, 100 sheets of PB paper (manufactured by Canon), which is plain paper, are used. Images were recorded one by one to produce recorded matter. Then, after the recordings were produced, the state of adhesion of aggregates on the surface of the recording head on which the nozzle rows were formed was observed. As a result, adhesion of aggregates was not observed and nozzle clogging did not occur.

[Sixth Embodiment]
In the ink jet recording head according to the present embodiment, an additive for controlling the cohesiveness is added to the pigment ink to adjust the cohesiveness of the ink in order as desired, and the pigment ink is ejected in the order of the low cohesiveness of the pigment ink. The nozzle row was arranged close to the nozzle row for discharging the reaction liquid.

  In the black pigment ink k1, the cyan pigment ink c1, the magenta pigment ink m1, and the yellow pigment ink y1, the aggregate strength was c1> k1> y1> m1 in descending order. Here, 100 parts of the black pigment ink k1 was added with 1 part of an acrylic resin Joncrill 586 (product name: Johnson Polymer) to obtain a black pigment ink k3. Further, 100 parts of magenta pigment ink m1 was added with 1 part of acrylic resin Jonkrill 678 (product name: Johnson Polymer) to obtain magenta pigment ink m3. The size of the granular aggregates of the pigment inks k3, c1, m3, and y1 thus produced was measured by the method described in the above embodiment. Table 13 below shows the measurement results for k3, c1, m3, and y1.

  Thus, by adding the additive for controlling the cohesiveness to the pigment ink, k3> c1> m3> y1 can be changed in order from the strongest aggregate, and the order of the cohesiveness between the pigment inks can be changed. I was able to change it. FIG. 9 is a schematic configuration diagram of the ink jet recording head in the present embodiment, and five nozzle rows 101, 102, 103, 104, and 105 are formed as in FIG. 1A described above. These nozzle rows 101, 102, 103, 104, and 105 are supplied so as to eject the reaction liquid S1, the yellow pigment ink y1, the magenta pigment ink m3, the cyan pigment ink c1, and the black pigment ink k3.

  The reaction liquid s1 is discharged from the nozzle row 101, and the black pigment ink k3 having the highest aggregate strength is discharged from the nozzle row 105. The cyan pigment ink c1 is ejected from the nozzle row 104, the magenta pigment ink m3 is ejected from the nozzle row 103, and the yellow pigment ink y1 having the lowest cohesiveness is ejected from the nozzle row 102. Using the recording apparatus, as in the first embodiment, the reflection density and the saturation of a recorded matter produced by recording an image on plain paper were measured.

  By using the black pigment ink k3 as the ink having the highest aggregate strength, it is possible to improve the reflection density of the recorded matter produced using the black pigment ink on plain paper, and the character quality is high using the black pigment ink. It becomes possible to create a recorded matter. In addition, by setting the color ink with higher lightness so that the cohesion is lower, the color matter as a whole can be highly saturated, and a recorded matter with high image quality can be created.

  Next, the glossiness of the recorded matter in which the image was recorded on the special paper was measured. The measurement method is the same as in the first embodiment.

  Even when an additive for controlling the cohesiveness was added, since the nozzle rows were set in the order of the cohesive strength, there was little variation in the glossiness between the inks, and good glossiness was obtained.

  Next, using one of the black pigment ink k3, the cyan pigment ink c2, the magenta pigment ink m3, and the yellow pigment ink y2 and the reaction liquid s1, 100 sheets of PB paper (manufactured by Canon), which is plain paper, are used. Images were recorded one by one to produce recorded matter. Then, after the recordings were produced, the state of adhesion of aggregates on the surface of the recording head on which the nozzle rows were formed was observed. As a result, adhesion of aggregates was not observed and nozzle clogging did not occur.

[Comparative example]
As a comparative example, a case will be described in which a nozzle row for discharging pigment ink having the highest aggregate strength is arranged as an adjacent nozzle row adjacent to a nozzle row for discharging a reaction liquid. Similarly to the above-described embodiment of the present invention, the nozzle row 101 for the reaction liquid discharge, the nozzle row 102 for the adjacent nozzle row adjacent to the nozzle row 102, and the nozzle rows 102, 104, and 105 are positioned away from the nozzle row 101.

  In this example, the reaction liquid s1, the black pigment ink k2, the cyan pigment ink c2, the magenta pigment ink m2, and the yellow pigment ink y2 are discharged using an inkjet recording head in which five nozzle rows are arranged as shown in FIG. To do. The nozzle array 101 discharges the reaction liquid s1, and the nozzle array 102 discharges the black pigment ink k2 having the highest aggregate strength. Further, the cyan pigment ink c2 is ejected from the nozzle row 103, the magenta pigment ink m2 is ejected from the nozzle row 104, and the yellow pigment ink y2 is ejected from the nozzle row 105.

  Using the recording apparatus, as in the first embodiment, the reflection density and the saturation of a recorded matter produced by recording an image on plain paper were measured.

  By discharging the black pigment ink k2 having the highest aggregate strength from the adjacent nozzle row 102 adjacent to the nozzle row 101 for discharging the reaction liquid, a part of the discharge nozzle is blocked, and the reflection density of the recording portion is reduced. It was seen.

  Next, the glossiness of the recorded matter in which the image was recorded on the special paper was measured. The measurement method is the same as in the first embodiment.

  By ejecting the black pigment ink k2 from the adjacent nozzle row 102 with the ink having the highest aggregate strength, a large aggregate is formed in the recording portion drawn with the black pigment ink k2, and the unevenness of the surface of the recording medium is increased. It was. Therefore, it is considered that the glossiness has decreased.

  Next, using one of the black pigment ink k2, the cyan pigment ink c2, the magenta pigment ink m2, and the yellow pigment ink y2 and the reaction liquid s1, 100 sheets of PB paper (manufactured by Canon), which is plain paper, are used. Images were recorded one by one to produce recorded matter. Then, after the recordings were produced, the state of adhesion of aggregates on the surface of the recording head on which the nozzle rows were formed was observed. As a result, adhesion of aggregates was observed, and in particular, aggregates were vigorously adhered around the nozzle row 102 for discharging the black pigment ink k2. In addition, when an image was recorded using the black pigment ink k2, the image was blurred with about 10 sheets, and nozzle clogging occurred.

(Other embodiments)
In each of the above-described embodiments, an example in which nozzle rows corresponding to five types of cyan, magenta, yellow, black, and reaction liquid are provided in one recording head is illustrated, but the present invention is not limited to this embodiment. . Of these five types, at least one specific liquid (for example, K · S) is provided in the first recording head, and liquids other than the specific liquid (for example, M • Y • C) are provided in the second recording head. The form which provides may be sufficient. Further, the nozzle rows corresponding to these five kinds of liquids may be provided in different recording heads independently. As described above, regardless of the form of the recording head, if the nozzle row of the pigment ink having the strongest aggregate strength is arranged so as not to be adjacent to the nozzle row of the reaction liquid, the scope of the present invention. Is included.

(A), (b) is explanatory drawing of the basic structural example of the inkjet recording head which can apply this invention. (A), (b) is explanatory drawing of the discharge principle of the ink in the inkjet recording head which can apply this invention. It is explanatory drawing of the nozzle arrangement | sequence of the inkjet recording head in the 1st Embodiment of this invention. 1 is a perspective view of a recording apparatus to which the present invention can be applied. It is explanatory drawing of the nozzle arrangement | sequence of the inkjet recording head in the 2nd Embodiment of this invention. It is explanatory drawing of the nozzle arrangement | sequence of the inkjet recording head in the 3rd Embodiment of this invention. It is explanatory drawing of the nozzle arrangement | sequence of the inkjet recording head in the 4th Embodiment of this invention. It is explanatory drawing of the nozzle arrangement | sequence of the inkjet recording head in the 5th Embodiment of this invention. It is explanatory drawing of the nozzle arrangement | sequence of the inkjet recording head in the 6th Embodiment of this invention. It is explanatory drawing of the nozzle arrangement | sequence of the inkjet recording head as a comparative example.

Explanation of symbols

2 Heating resistor 5 Nozzle hole 7 Droplet 10, 11, 16 Inkjet recording head 101, 102, 103, 104, 105 Nozzle array s1 Reaction liquid c1, c2 Cyan pigment ink m1, m2 Magenta pigment ink y1, y2 Yellow pigment ink k1, k2 Black pigment ink

Claims (10)

In an inkjet recording head in which a plurality of nozzle arrays for discharging a plurality of different pigment inks and a liquid for aggregating the pigment contained in the pigment ink are arranged,
Among the plurality of pigment inks, the nozzle row that discharges the pigment ink having the strongest strength of the pigment aggregate formed by contact with the liquid is arranged at a position that is not adjacent to the nozzle row that discharges the reaction liquid. An ink jet recording head.   The inkjet recording head according to claim 1, wherein the nozzle row that discharges the pigment ink having the weakest aggregate strength is arranged at a position adjacent to the nozzle row that discharges the liquid.   The inkjet recording head according to claim 1, wherein the pigment ink contains at least a pigment, a resin, a water-soluble solvent, and water. The plurality of different pigment inks include a color pigment ink and a black pigment ink,
4. The ink jet recording head according to claim 1, wherein the black pigment ink has a stronger aggregate than the color pigment ink. 5. The plurality of different pigment inks include a black pigment ink and a plurality of color pigment inks,
4. The ink jet recording head according to claim 1, wherein the black pigment ink has a higher strength of aggregate than at least one of the plurality of color pigment inks. 5. The plurality of different pigment inks include a plurality of color pigment inks,
The ink jet recording head according to claim 1, wherein the plurality of color pigment inks have a higher strength of aggregate in descending order of lightness of the pigment ink. The plurality of pigment ink ejection nozzle arrays are arranged at positions sandwiched between at least two liquid ejection nozzle arrays,
7. The nozzle row that discharges the pigment ink having the strongest aggregate strength among the plurality of pigment inks is arranged at a position that is not adjacent to the liquid discharge nozzle row. The ink jet recording head according to any one of the above. The plurality of pigment ink ejection nozzle rows are arranged at positions sandwiching the liquid ejection nozzle rows,
7. The nozzle row that discharges the pigment ink having the strongest aggregate strength among the plurality of pigment inks is arranged at a position that is not adjacent to the liquid discharge nozzle row. The ink jet recording head according to any one of the above. In an inkjet recording apparatus that records an image on a recording medium using a plurality of nozzle arrays for ejecting a plurality of different pigment inks and a nozzle array for ejecting a liquid that aggregates the pigment contained in the pigment ink ,
Among the plurality of pigment inks, the pigment ink having the strongest strength of the aggregate of pigments formed by contact with the liquid is ejected from a predetermined nozzle row not adjacent to the nozzle row for ejecting the liquid. An ink jet recording apparatus. In an inkjet recording method for recording an image on a recording medium using a plurality of nozzle rows for discharging a plurality of different pigment inks and a nozzle row for discharging a liquid that aggregates the pigment contained in the pigment ink ,
Of the plurality of pigment inks, the pigment ink having the strongest strength of the aggregate of pigments formed by contact with the liquid is ejected from a nozzle row that is not adjacent to the nozzle row that ejects the liquid. Inkjet recording method.

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