JP2012158187A - Inkjet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress waviness of a recording medium and enable recording with high image quality, by evenly controlling the application amount of a preprocessing solution to the recording medium.SOLUTION: The inkjet recording apparatus includes: an application roller (25) for applying the preprocessing solution to the recording medium; a counter roller (26) facing the application roller; and an inkjet head for performing recording on the recording medium, and images are recorded on the recording medium to which the preprocessing solution is applied between the application roller and the counter roller. The apparatus has a first guide unit (51) for guiding the recording medium between the application roller and the counter roller, and the first guide unit guides the recording medium toward the counter roller side.

Description

  The present invention relates to an ink jet recording apparatus, and more particularly to a recording medium pretreatment means effective for an ink jet image recording method. Specifically, before applying a pretreatment liquid for improving image quality. The present invention relates to an ink jet recording apparatus provided with a treatment liquid coating apparatus.

  In recent years, inkjet printers are rapidly spreading due to advantages such as low noise, low running cost, and easy colorization. However, when recorded on plain paper, in addition to initial quality problems such as bleeding, density, color tone, and show-through, there were problems related to image robustness such as water resistance and weather resistance. Proposals have been made.

  As a means for solving these problems, when an image is formed with ink, a recording material in which a material for fixing the dye in the ink is fixed on the surface of the recording material, such as plain paper, or a white pigment or the like on the surface. Patent Documents 1 to 4 disclose that a recording material coated with a water-soluble polymer is used. However, this method requires the purchase of special paper that has been pre-coated, so there is the inconvenience that it is not possible to freely use paper that is close to you, and there is a problem with the ease of writing with a pencil or pen. there were.

  Further, Patent Document 5 discloses that ink permeability is increased by adding a surfactant or the like to ink in order to suppress bleeding at a color boundary such as a two-color overlapping portion. This method is effective for resolving bleeding at the color boundary such as the two-color overlapped area and smearing (image contamination due to contact after printing) because the ink penetrates the recording paper at a high speed. The image cannot be resolved. Furthermore, although a method of adding a volatile solvent to the ink is disclosed in Patent Document 6, the same effect as that of the permeable ink can be obtained, but the nozzle is likely to be clogged. In addition, in order to improve water resistance and light resistance, the use of ink containing a pigment as a colorant has also increased, but it is difficult to maintain the reliability around the nozzle such as clogging with an ink containing a pigment, Further, when high color reproducibility such as a photographic image or CG is required, there is a problem that cyan and magenta color development is insufficient and a satisfactory image cannot be obtained.

  Therefore, in order to solve such a problem, Patent Document 7 discloses that a polymer solution such as carboxymethyl cellulose, polyvinyl alcohol, polyvinyl acetate or the like is sprayed on the recording material in advance, and then the polymer solution adheres to the part. An ink jet recording method for printing by ejecting ink has been proposed. However, although this method can improve the sharpness of the printed image, it is not effective to improve the drying property of the printed image, and the effect of improving the image quality in the color image is not recognized so much. Also, there is a patent on an ink jet recording method in which an image recording acceleration liquid containing a compound that insolubilizes a dye in the ink is deposited on a recording material by an ink jet method, and then the ink is ejected and printed on a portion where the image recording acceleration liquid is adhered. It is disclosed in documents 8 to 10 and the like.

  However, in the method in which the image recording accelerating liquid is adhered to the recording material by the ink jet method, the amount of moisture adhering at the two-color overlapping portion is large, so that bleeding at the color boundary cannot be sufficiently suppressed, and the ink There is a problem that show-through is large. Furthermore, there is a problem that cockling (waving) of the recording material occurs. In addition, since the image recording acceleration liquid is sprayed with an inkjet head, there are restrictions on the viscosity and surface tension of the liquid in order to obtain stable injection, and there are restrictions on the nozzle diameter and composition of the liquid in order to prevent clogging. There was a problem that conditions were added and the degree of freedom was significantly reduced. On the other hand, there is an increasing need for higher recording speeds, and development of high-speed systems using line-scanning ink-jet heads has also become active. However, the recording speed of the line scanning ink jet head can be 100 ppm or more based on the ink ejection performance of the head, but in reality, the ink cannot be absorbed by the paper, and the image blurs or the paper undulates. It is difficult to achieve high speed with high image quality.

  The present invention is for solving such problems, and an ink jet recording apparatus capable of suppressing waviness of the recording medium and capable of high-quality recording by uniformly controlling the amount of pretreatment liquid applied to the recording medium. The purpose is to provide.

  In order to solve the above problems, the application roller and the counter roller are provided with an application roller for applying the pretreatment liquid to the recording medium, a counter roller facing the application roller, and an inkjet head for recording on the recording medium. In the ink jet recording apparatus of the present invention, an image is recorded on a recording medium coated with a pretreatment liquid between the first and second guide portions for guiding the recording medium between the coating roller and the counter roller. The first guide portion is characterized in that it guides the recording medium toward the counter roller side.

  In addition, a second guide portion that guides the recording medium discharged from between the application roller and the counter roller is provided, and a tip portion of the second guide portion that faces between the application roller and the counter roller has an application It is provided toward the roller side.

  Further, the application roller and the counter roller were installed so as to be inclined from the vertical direction when viewed from the axial direction of the two rollers.

  The pretreatment liquid is a liquid containing a color material flocculant.

  Further, the pretreatment liquid contains 10 to 80% by weight of water or a wet organic solvent and a cationic resin.

  The present invention includes the first guide portion that guides the recording medium toward the counter roller, so that the recording medium is preliminarily treated with the pretreatment liquid at the clamping position between the application roller to which an appropriate pressure is applied and the counter roller. Because of the contact, the amount of pretreatment liquid applied can be uniformly controlled, the undulation of the recording medium can be suppressed, and high-quality recording can be performed.

1 is a cross-sectional view illustrating a configuration of an ink jet recording apparatus according to an embodiment of the present invention.

  FIG. 1 is a cross-sectional view showing a configuration of an ink jet recording apparatus according to an embodiment of the present invention. In the figure, the ink jet recording apparatus 1 of the present embodiment is mainly configured to include a paper supply unit 10, a pretreatment liquid coating unit 20, and an image recording unit 30. The paper supply unit 10 includes a paper supply roller 12 that sends out the paper 11. The pretreatment liquid coating unit 20 stores a pretreatment liquid 22 that is a liquid containing a colorant and a compound that insolubilizes the colorant in a recording liquid composed of a solvent that disperses or dissolves the colorant, and paper. 11 is guided to the counter roller 26 side, which will be described later, and the coating roller 25, which will be described later, and the lower surface, which is disposed on the discharge side of the counter roller 26 and to which the pretreatment liquid is applied, are avoided immediately after application. A pretreatment liquid tank 21 including a second guide portion 52 provided on the application roller 25 side and below the roller clamping portion, and a pumping roller 23 for stirring and pumping the pretreatment liquid 22; , A film thickness control roller 24 for controlling the pumped pretreatment liquid to a uniform film thickness on the application roller 25, and a cowling for applying the pretreatment liquid 22 to the paper 11 conveyed by the application roller 25. It is configured to include a Tarora 26. Then, the image recording unit 30 is passed between the belt driving rollers 32 and 33, and the belt driving rollers 32 and 33 are rotated so that the conveyed paper 11 is in the sub-scanning direction in the direction of the arrow. A sheet conveying belt 31 that continuously conveys the sheet 11 at a constant speed, a conveying roller 34 that guides the sheet 11 on the sheet conveying belt 31, a conveying roller 35 that pushes out the sheet 11 after recording, and the width of the sheet 11 A line scanning type black ink jet head 36, a cyan ink jet head 37, a magenta ink jet head 38, and a yellow ink jet head 39 each having a recordable nozzle are included. The line scanning type black inkjet head 36, cyan inkjet head 37, magenta inkjet head 38, and yellow inkjet head 39 are arranged at regular intervals, and record images in synchronization with the feed speed of the paper 11. I will do it. The recorded paper 11 is discharged to a discharge portion by discharge rollers 40 and 41. Each color tank 46 is arranged and supplied to each head by a tube (not shown). The pretreatment liquid is also disposed at the same position and supplied to the pretreatment liquid tank 21 by a tube (not shown) so that the liquid level 21-1 is maintained at a constant height.

Next, a series of image recording operations in the ink jet recording apparatus of the present embodiment having such a configuration will be described.
The paper 11 stored in the paper feed unit 10 is sent out by a paper feed roller 12. On the other hand, the pretreatment liquid 22 in the pretreatment liquid tank 21 of the pretreatment liquid coating unit 20 is pumped up by the pumping roller 23, and is controlled to have a uniform film thickness on the roller surface of the coating roller 25 by the film thickness control roller 24. . Then, the sheet 11 conveyed by the sheet feeding roller 12 is guided to the counter roller 26 side by the first guide unit 51 and comes into contact with the counter roller 26, and then the sheet 11 starts only at a portion sandwiched between the two rollers. Accordingly, the pretreatment liquid 22 is uniformly and thinly applied to the recording area of the paper 11 by the application roller 25 and the counter roller 26. Since the sheet 11 coated with the pretreatment liquid is guided along the second guide portion 52, contact immediately after the application to the lower surface coated with the pretreatment liquid can be avoided. Next, the paper 11 is transported along the paper guide 44 by the transport rollers 42 and 43, and further fed onto the paper transport belt 31 along the paper guide 45. Thereafter, the paper 11 on which the pretreatment liquid has been applied is continuously conveyed in the sub-scanning direction at a constant speed by the paper conveying belt 31, and is sequentially line-scanned black inkjet head 36, cyan inkjet head 37, magenta inkjet. An image is recorded by the head 38 and the yellow inkjet head 39. The paper 11 for which recording has been completed is discharged to the discharge section by the discharge rollers 40 and 41.

  Here, the time t (sec) when the ink droplet printed on the paper 11 is fixed by the action of the pretreatment liquid 22 is zero when the adjacent dots are hit, and the bleeding area between the ink colors is 0. .1 mm or less. If the area of bleeding (bleeding) between ink colors is 0.1 mm or less, there is virtually no problem as a visually sharp boundary image as a result of the sensory test. That is, in the ink jet recording apparatus of the present embodiment, the time t (sec) when the ink droplet printed on the paper 11 is fixed by the action of the pretreatment liquid 22 is to record a solid image of a certain color, Even when a solid image is recorded from the next adjacent line in another color, it is a time during which the bleeding and color mixing at the color boundary falls within 0.1 mm. The printing time interval at the color boundary point is s / V where s (mm) is the distance between the inkjet heads of each color and V (mm / sec) is the paper speed. If this time interval is longer than the time t (sec) at which the ink droplets are fixed by the action of the pretreatment liquid, the color blur at the boundary falls within one dot line, so s / V (sec) is t (sec) or more. That is, V (mm / sec) may be s / t (mm / sec) or less. Therefore, by setting V = s / t, the highest speed recording can be achieved within a range where the image quality is allowed.

  The above is a solution to bleeding at the color boundary, but even when drawing a figure or character with the same color, if the printing timing of the next adjacent dot is too early, it may cause blurring or blurring. When an extremely sharp image without blur is required, it can be achieved by setting the paper feed speed V as follows. Since the recording density in the paper feeding direction is Dd (dpi), and the time for sending one dot pitch is (25.4 / Dd) / V, this is the time t (sec) for fixing the ink droplets by the action of the pretreatment liquid. That's all there is to it. That is, if V is equal to or less than (25.4 / Dd) / t (mm / sec), an extremely sharp image with no blur or blur can be obtained. The recording speed is the fastest when V = (25.4 / Dd) / t (mm / sec). In this case, the maximum ejection frequency of the inkjet head is (V / 25.4) × Dd (Hz).

  Further, as the pretreatment liquid 22, the liquid containing the colorant flocculant contains water or a wet organic solvent and 10 to 80% by weight of a cationic resin represented by the following general chemical formulas (1) to (8). In this case, t is about 150 μsec, the recording density in the feeding direction of the paper 11 is 600 dpi, the ejection frequency of the ink jet head is about 6.7 kHz, and the speed equivalent to 80 ppm (corresponding to the lateral feeding of the paper size A4). A good image was obtained experimentally.

  The cationic resins represented by the general chemical formulas (1) to (8) preferably have a weight average molecular weight in the range of 1000 to 100,000, more preferably 2000 to 50,000, and still more preferably 2000 to 30,000. Are preferred. When the weight average molecular weight is greater than 100,000, the pretreatment liquid becomes non-uniform because it is difficult to dissolve in a solvent, and uneven image quality is likely to occur. Conversely, when the weight average molecular weight is less than 1000, the effect of preventing bleeding and improving water resistance is small, which is not preferable. Further, in order to obtain high reactivity with the anionic component, the cationic degree of the cationic resin at pH 3 is preferably 3 meq / g or more, more preferably 3.5 meq / g. The cation degree is determined by colloid titration using a polyvinyl potassium sulfate reagent. Specifically, it can be obtained by the following procedure. That is, 90 ml of deionized water is taken into a conical beaker, 10 ml of a 500 ppm aqueous solution of a sample (converted to a dry product) is added to pH 4.0 with an aqueous hydrochloric acid solution, and the mixture is stirred for about 1 minute. Then add 2-3 drops of toluidine blue indicator and titrate with N / 400 potassium potassium sulfate reagent (N / 400 PVSK). The titration rate is 2 ml / min, and the end point is the time when the sample water changes from blue to magenta and is held for 10 seconds or more. Cation degree (meq / g) = (N / 400 PVSK titration) × (N / 400 PVSK titer) / 2. The higher the degree of cation, the stronger the cationicity and the more efficient reaction with the anionic component in the recording liquid, thus reducing the required amount of pretreatment liquid and causing curling and cockling of the recording material. Therefore, it is possible to obtain a high quality image.

  The counter ion of the cationic resin includes inorganic anions such as halogen ions, nitrate ions, nitrite ions, acetate ions, phosphate ions, sulfate ions, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, glycolic acid, gluconic acid, Any organic anion derived from an organic acid such as lactic acid may be used. However, considering the reactivity with anionic components in the recording liquid, it is ionically dissociated at a high rate in the pretreatment liquid. Therefore, monovalent anions selected from halogen ions, nitrate ions, nitrite ions, and acetate ions are particularly preferable.

  Commercially available products can be used for these cationic resins. Specifically, PAA-HCl-3L, PAA-HCl-10L (polyallylamine hydrochloride), PAA-10C (polyallylamine) (manufactured by Nittobo) Q-101 (polyamine-based), Q-311 (polyamine-based) ), Q-501 (polyamine type), (manufactured by Hymo Co., Ltd.), Ako Flock C567, C573, C577, C581 (polyamine type), (manufactured by Mitsui Cytec Co., Ltd.), and the like. These cationic resins may be used alone or in combination of two or more.

  Examples of means for applying the pretreatment liquid in contact with the recording material include roller coating and a coating method using a wire bar or a blade. In these methods, it is possible to uniformly apply a pretreatment liquid for a recording material having a high viscosity, which could not be applied as droplets by the ink jet method, to the recording material. Furthermore, the recording material pretreatment liquid applied by the contact applying means can also contain a number of additives that could not be compounded by the above-described conventional method. The degree of freedom in formulating the treatment liquid can be greatly expanded.

  In particular, if the means for applying the pretreatment liquid in contact with the recording material is a roller application means, it is possible to apply a very small amount of the high-viscosity pretreatment liquid. It is preferable because the means can be manufactured at a low cost and in a compact manner.

  As described above, a high-viscosity pretreatment liquid that cannot be used in the pretreatment method in which droplets are ejected by the ink jet method can be used. That is, the pretreatment liquid can contain a cationic resin at a high concentration. By depositing in a thin layer with a high concentration, the amount of deposition can be reduced, and the cationic resin remains in the vicinity of the surface, so that the image quality is remarkably improved and curling, cockling, etc. of the recording material can be suppressed. Specifically, the content of the cationic resin contained in the pretreatment liquid is preferably 10 to 80% by weight. If it is less than 10% by weight, image quality improvement effects such as fine line reproducibility, reduction of feathering and blurring of color boundaries, improvement of image density, reduction of back-through density, etc. cannot be obtained, and 80% by weight. If the amount is larger than the above, the change in physical properties due to evaporation of the solvent component is remarkably changed, and it is difficult to uniformly apply the predetermined amount.

  The viscosity of the pretreatment liquid is preferably 10 to 10000 mPa · s (25 ° C., rotor No. 4, rotation speed 30 rpm), more preferably 10 to 1000 mPa · s with a B-type viscometer. Is preferred. The pretreatment liquid is on the surface of the recording material, and an image quality improvement effect such as reproducibility of fine lines, improvement of water resistance, and prevention of bleeding can be obtained by ionic interaction with an anionic component in the recording liquid. However, when the viscosity of the pretreatment liquid is less than 10 mPa · s, the pretreatment liquid penetrates into the recording material, and the effect of preventing feathering and color boundary bleeding is small. In this case, in order to obtain a sufficient image quality improvement effect, if a large amount of pretreatment liquid is applied, the pretreatment liquid penetrates into the recording material, and the colorant also penetrates into the recording material. Reduces image density. Further, the solvent component contained in the pretreatment liquid tends to cause curling and cockling of the recording material. On the other hand, when the viscosity of the pretreatment liquid is greater than 10,000 mPa · s, it is difficult to uniformly apply to the recording material, which is not preferable.

  In order to adjust to a desired viscosity, the pretreatment liquid may contain various solvents. As the solvent, water is particularly preferable from the viewpoints of the solubility of the cationic resin and the safety and cost of the pretreatment liquid. The water content is preferably 5 to 80% by weight. If it is less than 5% by weight, the cationic resin is not easily dissolved stably. If it is more than 80% by weight, image bleeding tends to occur, and curling and cockling of the recording material tend to occur, which is not preferable.

  Further, when the viscosity changes due to evaporation of a solvent component such as water in the pretreatment liquid, the amount applied to the recording material also changes, and a certain image quality cannot be ensured. Besides preventing drying, in order to make the pretreatment liquid of the recording material have the desired physical properties, to improve the dissolution stability of the compound and other additives that insolubilize the colorant in the recording liquid, and to pretreat the recording material The following water-soluble organic solvents can be used for the purpose of stabilizing the coating properties of the liquid. The content of the water-soluble organic solvent is preferably in the range of 5 to 70% by weight. If it is less than 5% by weight, the effect of stabilizing the viscosity by suppressing evaporation and the effect as a dissolution aid are insufficient, and if it is more than 70% by weight, it is not preferable because it induces back-through and image blur.

  That is, examples of water-soluble organic solvents include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,5 pentanediol, 1,6 hexanediol, glycerol, 1,2,6-hexanetriol, Polyhydric alcohols such as 1,2,4-butanetriol, 1,2,3-butanetriol, and petriol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether Polyhydric alcohol alkyl ethers such as tetraethylene glycol monomethyl ether and propylene glycol monoethyl ether, ethylene group Polyhydric alcohol aryl ethers such as coal monophenyl ether and ethylene glycol monobenzyl ether, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethylimidazolidinone, ε -Nitrogen-containing heterocyclic compounds such as caprolactam, amides such as formamide, N-methylformamide, N, N-dimethylformamide, amines such as monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine and triethylamine Sulfur-containing compounds such as dimethyl sulfoxide, sulfolane, thiodiethanol, propylene carbonate, ethylene carbonate, γ-butyrolactone, and the like can be used. These solvents can be used alone or in combination with water.

  Among these, particularly preferred are diethylene glycol, thiodiethanol, polyethylene glycol 200 to 600, triethylene glycol, glycerol, 1,2,6-hexanetriol, 1,2,4-butanetriol, petriol, 1,5. -Pentanediol, N-methyl-2-pyrrolidone, N-hydroxyethylpyrrolidone, 2-pyrrolidone, 1,3-dimethylimidazolidinone, and the compounds that use these to insolubilize the colorant in the recording liquid and others An excellent effect is obtained with respect to the high solubility of the additive and the prevention of coating failure due to water evaporation.

  Furthermore, it is preferable to include a monohydric alcohol in the pretreatment liquid of the recording material, thereby preventing occurrence of uneven coating due to foaming of the pretreatment liquid of the recording material. An image having a uniform density can be obtained by forming the image by applying the pretreatment liquid in contact with the recording material and then ejecting the recording liquid as droplets to adhere to the recording material.

  The pretreatment liquid of this embodiment is suitable for high-speed recording as compared with the case where a colorless liquid composition containing a silicone compound and a cationic compound described in Patent Document 11 is used. In other words, the area where the silicone compound is attached has a remarkably low ink permeability, so the drying of the image area is slow, and when performing high-speed printing with this image forming method, the wettability to the recording medium is poor in addition to the low penetration. Adjacent dots are coalesced, and white stripes are generated in the solid image portion along the main scanning direction of the head, resulting in a problem that the image quality is remarkably deteriorated. Since the pretreatment liquid of this embodiment uses water and a water-soluble solvent as the main solvent, the wettability and permeability between the recording material to which the pretreatment liquid is applied and the recording liquid are not adversely affected. Therefore, good image quality can be obtained even when high-speed recording is performed. Moreover, the various components constituting the pretreatment liquid of the present embodiment are stable and do not cause any change in characteristics even after being stored for a long time.

  Furthermore, the pretreatment liquid of the present embodiment preferably contains 0.1 to 5% by weight of an antiseptic / antifungal agent. Because the pretreatment liquid is applied while being in contact with the recording material, contamination-causing substances such as paper dust are likely to be mixed in, causing the pretreatment liquid to be altered, resulting in a change in adhesion amount due to the alteration and a reduction in the image quality improvement effect itself. Sometimes. Therefore, by adding 0.1 to 5% by weight of antiseptic / antifungal agent, a pretreatment capable of acting stably for a long period of time can be obtained. Antiseptic and fungicides include sodium benzoate, sodium pentachlorophenol, sodium 2-pyridinethiol-1-oxide, sodium sorbate, sodium dehydroacetate, 1,2-dibenzisothiazolin-3-one (Proxel from Avica) CRL, proxel BDN, proxel GXL) and the like can be used. When the addition amount is less than 0.1% by weight, the antiseptic and antifungal effect is insufficient. When the addition amount is more than 5% by weight, the image quality is deteriorated.

  In addition, it is preferable to add a binder resin to the pretreatment liquid for the recording material of the present embodiment in order to improve fixability. Examples of the binder resin include acrylic resins, vinyl acetate resins, styrene-butadiene resins, vinyl chloride resins, acrylic-styrene resins, butadiene resins, and styrene resins.

  Furthermore, the pretreatment liquid for the recording material of the present embodiment can contain a surfactant. If the recording liquid is adhered to the recording material after the pretreatment liquid containing the cationic resin and the surfactant is applied to the recording material such as plain paper, irregularity due to the distribution of the surface sizing agent of the recording material Since wetting is reduced, an image with low feathering, excellent reproducibility of fine lines, etc., high image quality without blurring of color boundaries, and high image density can be obtained. This is presumably because the recording liquid uniformly penetrates the recording material and the color material becomes insoluble and stays in the vicinity of the surface of the recording material. Examples of surfactants include anionic surfactants such as sodium dodecylbenzenesulfonate, sodium laurate, ammonium salt of polyoxyethylene alkyl ether sulfate, distearyldimethylammonium chloride, stearyldimethylbenzylammonium chloride, stearyldimethylchloride Cationic surfactants such as benzylammonium, stearyltrimethylammonium chloride, cetyltrimethylammonium chloride, myristyldimethylbenzylammonium chloride, benzalkonium chloride, lanolinium ethylsulfate fatty acid aminopropylethyldimethylammonium chloride, didecyldimethylammonium chloride, imidazoline derivatives, etc. Amphoteric surfactants, polyoxyethylene alkyl ethers, polyoxyethylene alkyl alkyls Nonionic interfaces such as nyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkyl amine, polyoxyethylene alkyl amide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, ethylene oxide additive of acetylene alcohol An activator, a fluorochemical surfactant, etc. are mentioned. Specific examples of the solvent other than the surfactant include diethylene glycol monophenyl ether, ethylene glycol monophenyl ether, ethylene glycol monoallyl ether, diethylene glycol monophenyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, and tetraethylene glycol chlorophenyl ether. Low water solubility such as polyhydric alcohol alkyl and aryl ethers, lower alcohols such as ethanol and 2-propanol, 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol However, the present invention is not limited to this as long as it can be dissolved in the pretreatment liquid and adjusted to desired physical properties.

  The content of the compound in the pretreatment liquid is preferably 0.1 to 50% by weight. In order to ensure the uniformity of the pretreatment liquid, a cationic surfactant is particularly preferable among the surfactants. Thereby, the wettability between the recording liquid and the surface of the recording material is improved, and an image with high image quality and high image density and excellent water resistance can be obtained. Examples of the cationic surfactant include Ionette D46, Ionette LEC, Securyl VN, Sunstat 1200, Sunstat KT-305C, Cation G-50, Ionette RK-15 (manufactured by Sanyo Chemical Industries, Ltd.) and the like.

Specifically, as a kind of the cationic compound that insolubilizes the colorant, the dicyandiamide / formalin polycondensate, the dicyandiamide / diethylenetriamine polycondensate, epichlorohydrin / dimethylamine addition polymer, dimethyldiallylammonium chloride / SO ₂ of the present embodiment are used. In addition to copolymer, allylamine salt polymer, dialkylaminoethyl (meth) acrylate quaternary salt polymer, dimethyl diallyl ammonium chloride polymer, diallylamine salt / SO ₂ copolymer, polyallylamine, cationic epoxy resin, Polyethyleneimine, polyacrylamide, poly (meth) acrylic acid ester, polyvinylformamide, aminoacetalized polyvinyl alcohol, polyvinylpyridine, polyvinylbenzylphosphonium, cationic emma And John, etc., it is also possible to contain such polyvalent metal salts.

  Commercially available cationic resins can be used. Specifically, Sunstat E-818, Sunfix 70, Sunfix 555C, Sunfix LC-55, Sanfux PAC-700 Conch, Sanyo Elion A -3, Sunfix 414, Sunfix 555, Sunfix PRO-100, Sunfix 555US, Cellophor YM-500 (manufactured by Sanyo Chemical Industries, Ltd.), # 675, # FR-2P, # 1001 (manufactured by Sumitomo Chemical) Co., Ltd.), LUPASOL SC61B (manufactured by BASF) and the like. Moreover, ZP-700 (vinyl formamide type), MP-184 (polyacrylic acid ester type), MP-173H (polymethacrylic acid ester type), MP-180 (polymethacrylic acid ester type), MX-0210 (polymethacrylic acid type) Acid ester), MX-8130 (polyacrylate ester), E-395 (polyacrylate ester), E-305 (polyacrylate ester), Q-105H (dicyandiamide), Neo-600 ( (Polyacrylamide series), (manufactured by Hymo Co., Ltd.), Super Flock 2490 (Polyacrylate), Super Flock 3180, 3380, 3580, 3880, 3390, 3590, 3500, SD2081 (Polyacrylamide), Acofloc C498T, C498Y (Polyacrylic Acid ester-based), Super Flock 1500, 1600, Acofloc C481, C483, C485, C488, C480 (polymethacrylate ester) (manufactured by Mitsui Cytec Co., Ltd.), PAS-A-1, PAS-A-5, PAS-A-120L, PAS-A-120S, PSA-J-81, PAS-880, PAS-92 (diallyldimethylammonium salt copolymer), PAS-H-5L, PAS-H-10L, PAS- M-1 (diallyldimethylammonium salt polymer), (manufactured by Nittobo) and the like.

  Examples of the cationic emulsion include Acryt UW319-SX, Acryt RKW-460, Acryt RKW-400SX, Acryt RKW-450SX, and Acryt RKW-450 (manufactured by Taisei Kako Co., Ltd.).

  Polyvalent metal salts include magnesium nitrate hexahydrate, magnesium acetate tetrahydrate, calcium nitrate tetrahydrate, calcium acetate monohydrate, calcium chloride anhydrous, calcium lactate pentahydrate Examples include Japanese, calcium formate / anhydride, magnesium benzoate / trihydrate, magnesium sulfate / pentahydrate.

  Since the reactivity between the cationic resin in the pretreatment liquid and the anionic component in the recording liquid is the most efficient in the liquid phase, the pretreatment liquid was applied to the recording material by an applying means that contacts the recording liquid. After that, it is preferable to print with the recording liquid before the pretreatment liquid is dried. If high reactivity can be secured, the amount of pretreatment liquid used can be further reduced, and the image quality can be improved without causing curling and cockling of the recording material.

Preferably 0.5g / m ² ~10g / m ² as a deposition amount of the recording material of the pretreatment liquid of the recording material can be suppressed thereby better curl of the recording material. If it is less than 0.5 g / m ² , the effect of improving the image quality is insufficient. If it is more than 10 g / m ² , the recording material is curled or cockled, and the amount of adhesion is too large, so Increase.

  In addition, this invention is not limited to the said embodiment, It cannot be overemphasized that various deformation | transformation and substitution are possible if it is description in a claim.

1; inkjet recording apparatus; 10; paper supply unit;
11; paper, 12; paper feed roller, 20; pretreatment liquid application unit,
21; Pretreatment liquid tank, 22; Pretreatment liquid, 23; Pumping roller,
24; film thickness control roller; 25; coating roller; 26; counter roller;
30; Image recording unit, 31; Paper transport belt,
32, 33; belt drive roller,
34, 35, 40 to 43; transport rollers,
36-39; line scanning ink jet head,
44, 45; paper guide,
46; tank, 51; first guide part, 52; second guide part.

JP-A-56-86789 JP-A-55-144172 JP 52-53012 A JP-A-56-89594 JP 55-65269 A JP-A-55-66976 JP-A-56-89595 JP-A-64-63185 JP-A-8-20159 Japanese Patent Laid-Open No. 8-20161 JP-A-8-142500

In order to solve the above-mentioned problems, an application roller for applying a pretreatment liquid to a sheet , a counter roller facing the application roller, and an inkjet head for recording on the sheet are provided. A first guide for guiding a sheet between a coating roller and a counter roller in an inkjet recording apparatus that records an image with an inkjet head on a surface of a sheet coated with a pretreatment liquid. The first guide portion is characterized in that it guides the sheet toward the counter roller side.

In addition, a second guide portion that guides the sheet discharged from between the application roller and the counter roller is provided, and a tip portion of the second guide portion that faces between the application roller and the counter roller has an application roller. It is provided towards the side.

The present invention, by have a first guide portion for guiding to between the application roller and the counter roller the sheet guide portion of said first guiding the sheet toward the counter roller side, appropriate pressure Since the paper contacts the pretreatment liquid for the first time at the position where the application roller is applied and the counter roller, the application amount of the pretreatment liquid can be controlled uniformly, and the waviness of the paper is suppressed and high quality recording is performed. be able to.

Claims (5)

An application roller for applying the pretreatment liquid to the recording medium; a counter roller facing the application roller; and an ink jet head for recording on the recording medium; and the front roller between the application roller and the counter roller. In an inkjet recording apparatus for recording an image on the recording medium coated with a treatment liquid,
A first guide portion for guiding the recording medium between the application roller and the counter roller;
The ink jet recording apparatus, wherein the first guide portion guides the recording medium toward the counter roller side.   A second guide portion for guiding the recording medium discharged from between the application roller and the counter roller, and a tip portion of the second guide portion that faces between the application roller and the counter roller The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is provided toward the application roller side.   3. The ink jet recording apparatus according to claim 1, wherein the coating roller and the counter roller are installed so as to be inclined from a vertical direction when viewed from the axial direction of the two rollers.   The ink jet recording apparatus according to claim 1, wherein the pretreatment liquid is a liquid containing a color material flocculant.   The ink jet recording apparatus according to claim 1, wherein the pretreatment liquid contains 10 to 80% by weight of water or a wet organic solvent and a cationic resin.

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