JP2017094722A - Image formation method and image formation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image formation method that can form an image having excellent image density, image glossiness, fixability or blocking resistance.SOLUTION: The method includes step S101 for discharging liquid comprising a colorant and water on a recording medium, step S103 for spraying a face of the recording medium having the liquid discharged thereon with coating liquid comprising wax, and step S104 for heating the recording medium sprayed with the coating liquid.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image forming method and an image forming system.

  Compared to other recording methods, the inkjet recording method is simple because the process is simple, full-colorization is easy, and even a device with a simple configuration has the advantage that an image with high resolution can be obtained. From personal to office use, commercial printing and industrial printing are expanding.

  In the field of commercial printing and industrial printing, coated paper such as coated paper and art paper is used as a recording medium in addition to plain paper. In coated paper, in addition to image density, image glossiness is also used. In addition, fixing property and blocking resistance are required.

  Water-based ink is often used from the viewpoint of safety, ease of handling, and environmental considerations.

  In general, when an image is recorded by an ink jet recording method using water-based ink, the organic solvent containing water in the ink is slow to penetrate the coated paper, so that the organic solvent containing water is applied to the surface of the recording medium. Residual, the image was lost due to transfer or rubbing, and there was a problem in fixability.

Patent Document 1 discloses a resin-coated pigment in which at least a part of pigment particles is coated with a water-insoluble resin, resin particles, wax particles, 1,2-alkylenediol, polyhydric alcohol, pyrrolidone derivative, and acetylene glycol surfactant. An ink application step for applying ink to the recording medium from the discharge head, and applying the ink at a moving speed in the sub-scanning direction between the discharge head and the recording medium of 200 mm / sec or more, and recording with the ink applied A drying step of drying the medium, and a stacking step of stacking the recording medium after drying by providing a step of attaching 1 to 1000 mg / m ² of a powdery substance having an average particle diameter of 1 to 100 μm to the recording medium. An image forming method is disclosed.

  However, in addition to the fixability, at least one improvement in image density, image glossiness, or blocking resistance is required.

  An object of the present invention is to provide an image forming method capable of forming an image excellent in image density, image glossiness, fixing property or blocking resistance.

  In one embodiment of the present invention, an image forming method includes a step of discharging a liquid containing a coloring material and water onto a recording medium, and a step of spraying a coating liquid containing wax on a surface of the recording medium on which the liquid is discharged. And a step of heating the recording medium on which the coating liquid is spray-coated.

  ADVANTAGE OF THE INVENTION According to this invention, the image formation method which can form the image which is excellent in image density, image glossiness, fixing property, or blocking resistance can be provided.

It is a schematic diagram explaining an image forming apparatus and an image forming method according to the present embodiment. It is a flowchart explaining the image forming method using the image forming apparatus which concerns on this Embodiment. It is a schematic diagram explaining the spray coating apparatus which concerns on this Embodiment.

  Next, the form for implementing this invention is demonstrated.

  The image forming method includes a step of applying an ink containing a coloring material and water to a recording medium by inkjet, a step of spraying a coating liquid containing wax on the surface of the recording medium on which the ink is applied, and a coating liquid comprising: Heating the spray-coated recording medium.

  Here, by spray-coating the coating liquid on the surface of the recording medium on which the ink is applied, the wax fine particles are uniformly arranged on the surface layer of the surface of the recording medium on which the ink is applied. Also, by heating the recording medium sprayed with the coating liquid, the softening and melting of the wax microparticles is promoted, and the surface of the recording medium on which the ink is applied is thinly and uniformly coated with the wax. . As a result, an image having excellent image density, image glossiness, fixing property and blocking resistance can be formed on the coated paper.

  It is preferable to heat the recording medium sprayed with the coating solution so that the temperature is 0.45 to 1.25 times the melting point of the wax, and the temperature is 0.60 to 0.90 times the melting point of the wax. It is further preferable to heat the recording medium on which the coating liquid is spray-coated. By further improving the fixability and anti-blocking property of the image formed on the coated paper by heating the recording medium on which the coating solution is spray-coated so that the temperature becomes 0.45 times the melting point of the wax. Can do. On the other hand, by heating the recording medium sprayed with the coating liquid so that the temperature is 1.25 times or less the melting point of the wax, the image density, glossiness and fixability of the image formed on the coated paper can be reduced. Further improvement can be achieved.

  The recording medium is not particularly limited, and coated paper such as coated paper and art paper, plain paper, and the like can be used.

<Color material>
Although it does not specifically limit as a coloring material, A pigment and dye can be used. Among these, pigments are preferable from the viewpoints of image density, fixability, and blocking resistance of images formed on coated paper.

  Although it does not specifically limit as a pigment, The pigment which has at least 1 type of anionic hydrophilic group on the surface, and shows water dispersibility or water solubility is preferable. Examples of the water-dispersible or water-soluble pigment include a pigment (1) dispersed with a dispersant having at least one anionic hydrophilic group, and a pigment (2) coated with a resin having at least one anionic hydrophilic group. And at least one anionic hydrophilic group, an atomic group containing at least one anionic hydrophilic group, or a pigment (3) bonded with a resin having at least one anionic hydrophilic group.

  The pigment (1) is generally called a surfactant-dispersed pigment or a resin-dispersed pigment. The pigment has an interface between the pigment and water so that the pigment is dispersed in water.

  The pigment (2) is generally referred to as a capsule pigment, and has an anionic hydrophilic group, which is coated with a water-insoluble resin, and is made hydrophilic so that the pigment is dispersed in water. It is.

  The pigment (3) is generally called a self-dispersing pigment, and is mainly made hydrophilic by subjecting carbon black or the like to surface oxidation so that the pigment is dispersed in water.

  There is no restriction | limiting in particular as a pigment, According to the objective, it can select suitably, For example, any of an inorganic pigment and an organic pigment may be sufficient. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the inorganic pigment include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, bitumen, cadmium red, chrome yellow, metal powder, and carbon black. Among these, carbon black is preferable. In addition, as carbon black, what was manufactured by well-known methods, such as a contact method, a furnace method, a thermal method, is mentioned, for example.

  Examples of organic pigments include azo pigments, azomethine pigments, polycyclic pigments, dye chelates, nitro pigments, nitroso pigments, and aniline black. Among these, azo pigments and polycyclic pigments are preferable.

  Examples of the azo pigments include azo lakes, insoluble azo pigments, condensed azo pigments, and chelate azo pigments. Examples of the polycyclic pigment include phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinofullerone pigments, rhodamine B lake pigments, and the like. It is done. Examples of the dye chelates include basic dye chelates and acidic dye chelates.

  Examples of the black pigment include carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, copper, iron (CI pigment black 11), titanium oxide, and the like. And organic pigments such as aniline black (CI Pigment Black 1).

The carbon black, a furnace method, a carbon black produced by the channel method, primary particle diameter of 15Nm～40nm, BET specific surface area is ^{50m 2 / g~300m 2 / g,} DBP oil absorption amount 40 ml / 100 g to Those having 150 ml / 100 g, a volatile content of 0.5% to 10% and a pH value of 2 to 9 are preferred.

  A commercially available product can be used as the carbon black. Examples of commercially available products include No. 2300, no. 900, MCF-88, no. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, no. 2200B (all manufactured by Mitsubishi Chemical Corporation); Raven700, 5750, 5250, 5000, 3500, 1255 (all manufactured by Columbia); Regal400R, 330R, 660R, Mogu L, Monarch700, 800, 880, 900, 1000, 1100, 1300, Monarch 1400 (all manufactured by Cabot Corporation); Color Black FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, Printex 35, U, V, 140U, 140V, Special Black 6, 5, 4A, 4 (all manufactured by Degussa).

  There is no restriction | limiting in particular as a pigment which can be used for yellow ink with a pigment for color, According to the objective, it can select suitably, for example, C.I. I. Pigment yellow 1, C.I. I. Pigment yellow 2, C.I. I. Pigment yellow 3, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 16, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 73, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 75, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 98, C.I. I. Pigment yellow 114, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 129, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 150, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 174, C.I. I. And CI Pigment Yellow 180.

  There is no restriction | limiting in particular as a pigment which can be used for a magenta ink by the pigment for a color, According to the objective, it can select suitably, For example, C.I. I. Pigment red 5, C.I. I. Pigment red 7, C.I. I. Pigment red 12, C.I. I. Pigment red 48 (Ca), C.I. I. Pigment red 48 (Mn), 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, C.I. I. Pigment red 123, C.I. I. Pigment red 146, C.I. I. Pigment red 168, C.I. I. Pigment red 176, C.I. I. Pigment red 184, C.I. I. Pigment red 185, C.I. I. Pigment Red 202, Pigment Violet 19 and the like.

  There is no restriction | limiting in particular as a pigment which can be used for a cyan ink with a pigment for color, According to the objective, it can select suitably, for example, C.I. I. Pigment blue 1, C.I. I. Pigment blue 2, C.I. I. Pigment blue 3, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 15:34, C.I. I. Pigment blue 16, C.I. I. Pigment blue 22, C.I. I. Pigment blue 60, C.I. I. Pigment blue 63, C.I. I. Pigment blue 66; C.I. I. Bat Blue 4, C.I. I. Examples include Bat Blue 60.

  By using Pigment Yellow 74 as the yellow pigment, Pigment Red 122 and Pigment Violet 19 as the magenta pigment, and Pigment Blue 15: 3 as the cyan pigment, a balanced ink with excellent color tone and light resistance can be obtained. be able to.

<Water>
Examples of water include pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, and distilled water, high pure water, and ultrapure water.

  The water content in the ink is preferably 20 to 60% by mass.

<Ink>
In addition to the colorant and water, the ink contains an organic solvent, a surfactant, a resin, a pH adjuster, an antiseptic / antifungal agent, a rust inhibitor, an antioxidant, an ultraviolet absorber, an oxygen absorber, It may further contain a light stabilizer and the like.

  When manufacturing the ink, it is preferable to mix the components and then filter and degas coarse particles using a filter, a centrifugal separator, or the like.

  The viscosity of the ink at 25 ° C. is preferably 5.0 to 15.0 mPa · s, and more preferably 7.0 to 9.0 mPa · s. When the viscosity at 25 ° C. of the ink is 5 mPa · s or more, the fixability of the image formed on the coated paper can be further improved, and when it is 15 mPa · s or less, the ink is formed on the coated paper. The image glossiness of the image can be further improved.

  An ink jet recording apparatus can be used when ink is applied to a recording medium by ink jet.

<Inkjet recording apparatus>
The ink jet recording apparatus includes an ink container and records an image on a recording medium using a recording head. The ink jet recording apparatus has ink discharge means for discharging ink, and further includes other means appropriately selected as necessary, for example, stimulus generation means, control means, and the like.

  The ink discharge means is means for applying a stimulus to ink and discharging it. The ink discharge means is not particularly limited, and examples thereof include various nozzles for ink discharge (see the liquid discharge head 10 described later for details of the ink discharge means).

  The control means is not particularly limited as long as the operation of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as a sequencer and a computer.

  FIG. 1 is a schematic diagram illustrating an image forming apparatus and an image forming method according to the present embodiment. An image forming apparatus 1 illustrated in FIG. 1 is an ink jet recording apparatus, and includes a liquid discharge head 10 and a spray coating apparatus 20 as main components.

  In the image forming apparatus 1, from the upstream side in the direction in which the recording medium 300 is conveyed (arrow direction), the liquid discharge head 10, the hot air device 120, the heating roller 130, the spray coating device 20, the liquid supply device 30, and the hot air device. 140 and a heating roller 150 are arranged.

  FIG. 2 is a flowchart for explaining an image forming method using the image forming apparatus according to the present embodiment. In order to form an image using the image forming apparatus 1, first, in step S101, the color material and the recording material 300 such as coated paper unwound from the unwinding roller 110 and conveyed in the direction of the arrow An ink (liquid) containing water is applied (discharged) by the liquid discharge head 10 to form an image. Details of the liquid discharge head 10 will be described later.

  Next, in step S102, the formed image is dried by the contact between the warm air sent from the warm air device 120 and the heating roller 130 (first heating). Thereafter, in step S103, a coating liquid containing a non-volatile component is sprayed by the spray coating apparatus 20 together with a gas (hot air) having a predetermined temperature or higher, and is applied to the surface of the recording medium 300 on which the ink is applied (spray coating). ). The coating liquid is supplied from the liquid supplier 30 to the spray coating apparatus 20. Details of the spray coating device 20 and the liquid supply device 30 will be described later.

  Thereafter, in step S104, the image is dried again by the hot air sent from the hot air device 140 and the heating roller 150 (fixing step: second heating), and the recording medium 300 is taken up by the take-up roller 160. Thus, the image formation is completed. The hot air devices 120 and 140 and the heating rollers 130 and 150 are not essential components.

  In the example of FIGS. 1 and 2, a coating liquid containing a non-volatile component is sprayed by a spray coating device 20 together with a gas having a predetermined temperature or higher (hot air), and the surface of the recording medium 300 on which ink is applied is applied. A heating process for heating the recording medium 300 is provided both before and after the coating process. However, you may provide a heating process only in any one before and behind the process apply | coated with the spray coating apparatus 20. FIG.

  By providing a heating step before or after the step of applying by the spray application device 20, it is possible to further improve the fixing property and blocking resistance of an image formed on the recording medium 300 such as coated paper. it can. In particular, it is preferable to provide a heating step after the step of applying by the spray application device 20 in that the image fixing property and blocking resistance can be further improved.

[Liquid discharge head]
The liquid ejection head 10 is means for applying a stimulus to ink and ejecting it. There is no restriction | limiting in particular as irritation | stimulation, According to the objective, it can select suitably, A heat | fever (temperature), a pressure, a vibration, light, etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together. Of these, heat and pressure are preferred.

  Specific examples include a piezoelectric actuator such as a piezoelectric element, a thermal actuator that uses a phase change caused by film boiling of a liquid using an electrothermal transducer such as a heating resistor, a shape memory alloy actuator that uses a metal phase change caused by a temperature change, An electrostatic actuator using an electrostatic force can be used.

  There is no particular limitation on the mode of ink ejection, and it varies depending on the type of stimulation. For example, as a mode of ink ejection when the stimulus is heat, thermal energy corresponding to a recording signal is applied to the ink in the liquid ejection head 10 using, for example, a thermal head, and the thermal energy is used. Examples include a method in which bubbles are generated in the ink and the ink is discharged and ejected as droplets from the nozzle holes of the liquid discharge head 10 by the pressure of the bubbles.

  In addition, as a mode of ink ejection when the stimulus is pressure, for example, by applying a voltage to a piezoelectric element bonded to a position called a pressure chamber in the ink flow path in the liquid ejection head 10, Examples include a method in which the piezoelectric element is bent to reduce the volume of the pressure chamber, and ink is ejected and ejected as droplets from the nozzle holes of the liquid ejection head 10.

  In the example of FIG. 1, the liquid ejection head 10 is a full-line head, and black (K), cyan (C), magenta (M), and yellow (Y) from the upstream side in the conveyance direction of the recording medium 300. The four heads K, C, M, and Y that can handle the above are arranged.

<First heating>
The recording medium on which the ink is applied may be heated. Thereby, the fixability and blocking resistance of the image formed on the coated paper can be further improved.

  The method of heating the recording medium on which the ink is applied is not particularly limited, but the method of bringing the heated fluid into contact with the recording medium, the method of bringing the recording medium into contact with the heated object and heating by heat transfer, There is a method of directly heating a recording medium with energy rays such as infrared rays and far infrared rays.

<Wax>
Wax is an organic substance that becomes solid at room temperature and becomes liquid when heated. Although it does not specifically limit as wax, The wax which shows water solubility or water dispersibility can be used. As the water-soluble wax, a wax having a hydrophilic group such as a hydroxyl group, a carboxyl group, an ethylene oxide group, or an amino group can be used. Water dispersible waxes can be used primarily as wax emulsions.

  Specific examples of water-soluble or water-dispersible waxes include carnauba wax, candelilla wax, beeswax, rice wax, lanolin and other plants, animal waxes, paraffin wax, microcrystalline wax, polyethylene wax, polypropylene wax, oxidation Petroleum waxes such as polyethylene wax and petrolatum, mineral waxes such as montan wax and ozokerite, synthetic waxes such as carbon wax, Hoechst wax, polyethylene wax and stearamide, α-olefin / maleic anhydride copolymer, etc. These natural / synthetic wax emulsions and blended waxes can be used singly or in combination. Moreover, latex, a colloidal solution, a suspension, etc. can also be used as a wax which shows water solubility or water dispersibility.

  A commercially available wax may be used. Specific examples thereof include cellosol 524 (carnauba wax having a melting point of 83 ° C. and a particle size of 200 nm) (manufactured by Chukyo Yushi Co., Ltd.), HYTEC E-6500 ( Polyethylene wax having a melting point of 140 ° C. and a particle size of 60 nm) (manufactured by Toho Chemical Co., Ltd.), HYTEC E-8237 (polyethylene wax having a melting point of 106 ° C. and a particle size of 80 nm) (manufactured by Toho Chemical Co., Ltd.), HYTEC P-9018 ( Melting point: 156 ° C., polypropylene wax having a particle size of 60 nm (Toho Chemical Co., Ltd.), Nopcoat PEM-177 (melting point: 105 ° C., polyolefin wax having a particle size of 10 nm) (San Nopco), AQUACER 498 (melting point: 58 ° C. Of paraffin wax) (by Big Chemie Japan), AQUACER 535 Mixed wax having a melting point of 95 ° C. (produced by Big Chemie Japan), AQUACER 531 (polyethylene wax having a melting point of 130 ° C. and a particle size of 123 nm) (made by Big Chemie Japan), AQUACER 515 (melting point of 135 ° C., particle size 33 nm polyethylene wax) (manufactured by BYK Japan).

  The melting point of the wax is preferably 70 ° C to 170 ° C, and more preferably 100 ° C to 140 ° C. When the melting point of the wax is 70 ° C. or higher, the blocking resistance of the image formed on the coated paper can be further improved. When the wax is 170 ° C. or lower, the fixing of the image formed on the coated paper is fixed. The property can be further improved.

<Coating solution>
The coating solution preferably further contains a resin in addition to the wax. Thereby, the image glossiness and blocking resistance of the image formed on the coated paper can be further improved.

  The coating liquid can be produced, for example, by mixing a wax emulsion and a resin emulsion.

  The coating solution further contains an organic solvent, a surfactant, a pH adjuster, an antiseptic / antifungal agent, a rust inhibitor, an antioxidant, an ultraviolet absorber, an oxygen absorber, a light stabilizer and the like as necessary. You may go out.

  When spraying the coating liquid onto the recording medium, a spray coating device can be used.

<Spray coating device>
FIG. 3 is a schematic diagram for explaining the spray coating apparatus according to the present embodiment. As shown in FIG. 3, the spray application device 20 includes a sprayer 21 and a hot air generator 22.

  The sprayer 21 includes a liquid introduction path 211 through which a coating liquid is introduced from a liquid supply device 30 provided outside the spray coating apparatus 20, and a gas through which a predetermined temperature gas (hot air) is introduced from the hot air generator 22. An introduction path 212 and a nozzle 213 that mixes and sprays the coating liquid introduced into the liquid introduction path 211 and the gas introduced into the gas introduction path 212 are provided.

  The hot air generator 22 is a device that generates a gas (hot air) at a predetermined temperature and introduces the generated gas into the gas introduction path 212. The gas introduced into the gas introduction path 212 can be, for example, air or nitrogen. The temperature of the gas introduced into the gas introduction path 212 is preferably 50 ° C. or higher and 350 ° C. or lower.

  The temperature detection means 23 may be provided outside the end of the gas introduction path 212 near the nozzle 213 side. In this case, the temperature detection means 23 detects the temperature immediately before being introduced into the gas nozzle 213 introduced into the gas introduction path 212, and outputs the detection result to the hot air generator 22. As the temperature detection means 23, for example, a thermocouple can be used.

  The hot air generator 22 controls the temperature of the gas introduced into the gas introduction path 212 based on the detection result of the temperature detection means 23. For example, the temperature of the gas introduced into the gas introduction path 212 is controlled so that the temperature of the gas detected by the temperature detection means 23 is 50 ° C. or higher and 350 ° C. or lower.

  Note that the temperature detected by the temperature detector 23 and the actual gas (atmosphere) temperature may differ depending on the system configuration. If there is an equilibrium state in the vicinity of the temperature detection means 23 connected to the gas introduction path 212, the temperature detected by the temperature detection means 23 is the atmospheric temperature of the gas. However, depending on the installation location of the temperature detection means 23 and the like, it is assumed that there is a temperature difference between the temperature detected by the temperature detection means 23 and the actual atmospheric temperature of the gas. In this case, it goes without saying that the temperature control by the hot air generator 22 is performed in consideration of the temperature difference.

  When the temperature detection means 23 is not provided, a temperature difference between the temperature of the gas generated by the hot air generator 22 and the temperature of the gas near the end of the gas introduction path 212 on the nozzle 213 side is obtained in advance. The wind generator 22 should just generate | occur | produce the gas of the temperature which considered the temperature difference. For example, when the temperature difference obtained in advance is 5 ° C. and the temperature of the gas near the end of the gas introduction path 212 on the nozzle 213 side is to be 50 ° C., the hot air generator 22 generates 55 ° C. gas. The gas introduction path 212 may be introduced.

  The liquid supplier 30 introduces a coating liquid containing a volatile component into the liquid introduction path 211 with a predetermined liquid feeding amount. As a method for introducing (feeding) the coating liquid into the liquid introduction path 211 by the liquid supply device 30, for example, a pressure method for feeding by a pump or a pressure tank, or a siphon method for feeding by utilizing a gas suction effect Etc.

  In the example of FIG. 3, the liquid supply device 30 is provided separately from the spray application device 20, but the liquid supply device 30 may be incorporated into the spray application device 20. In this case, the spray coating apparatus 20 includes a sprayer 21, a hot air generator 22, and a liquid supplier 30.

  The material of the liquid introduction path 211, the gas introduction path 212, and the nozzle 213 is not particularly limited, but SUS304, SUS316, brass, iron, aluminum, polypropylene, ABS resin, fluororesin, hard polyvinyl chloride, or the like is used. Can do.

  In FIG. 3, reference numeral 300 denotes a recording medium, and 310 denotes ink applied to the recording medium 300 by a liquid discharge head. The recording medium 300 is, for example, roll paper and can be conveyed in the direction of the arrow.

  The spray coating apparatus 20 mixes the coating liquid containing the non-volatile component introduced into the liquid introduction path 211 and the gas at a predetermined temperature introduced into the gas introduction path 212 in the nozzle 213 and directs the ink from the nozzle 213 toward the ink 310. Spray. The distance between the tip of the nozzle 213 and the recording medium 300 is not particularly limited, but can be, for example, about several tens of centimeters.

  For example, a gas at a predetermined temperature is always introduced from the hot air generator 22 into the gas introduction path 212, and the coating liquid is introduced from the liquid supplier 30 at a predetermined timing, so that the nozzle 213 sprays at an arbitrary timing. be able to. Although it does not specifically limit as a spray pattern of the nozzle 213, A flat pattern, a full cone pattern, a holo cone pattern, a straight pattern, etc. are mentioned.

  The spray nozzle of the spray coating apparatus for coating the coating liquid is not particularly limited, but a one-fluid nozzle for spraying the coating liquid alone and a two-fluid nozzle for spraying the coating liquid by mixing the coating liquid and gas (FIG. 3). ) A two-fluid nozzle is preferred from the viewpoint of fixability and image density of an image formed on coated paper.

<Second heating>
The method of heating the recording medium on which the coating liquid is spray-coated is not particularly limited, but the method of bringing the heated fluid into contact with the recording medium, and the method of bringing the recording medium into contact with the heated object and heating by heat transfer There is a method of directly heating the recording medium with energy rays such as infrared rays and far infrared rays.

  The image forming method includes, for example, an ink jet recording apparatus that discharges ink containing a coloring material and water to a recording medium, and a spray that applies a coating liquid containing wax on the surface of the recording medium on which ink is applied. The present invention can be carried out using an image forming system including a coating device and a heating device that heats a recording medium on which the coating liquid is spray-coated.

  In this example, “part” means “part by mass”.

[Pigment Dispersion PD-1 (Black)]
160 parts of carbon black NIPEX 160 (manufactured by Degussa) having a BET specific surface area of 150 m ² / g, an average primary particle size of 20 nm, a pH of 4.0, and a DBP oil absorption of 620 g / 100 g, polyoxyethylene (POE) (m = 40) 400 parts of β-naphthyl ether (manufactured by Takemoto Yushi Co., Ltd.) and 440 parts of ion-exchanged water were premixed to prepare a mixed slurry. Using a zirconia bead with a diameter of 0.05 mm (filling rate 55%), mixed slurry for 3 minutes at a peripheral speed of 10 m / s and a liquid temperature of 10 ° C. Was circulated and dispersed. Next, coarse particles were centrifuged with a centrifuge Model-7700 (manufactured by Kubota Corporation) to obtain a pigment dispersion PD-1 having a pigment concentration of 16% by mass.

[Pigment dispersion PD-2 (cyan)]
Pigment dispersion PD-2 having a pigment concentration of 16% by mass, in the same manner as pigment dispersion PD-1, except that carbon black was changed to pigment blue 15: 3 chromofine blue (manufactured by Dainichi Seika Co., Ltd.) Got.

[Pigment dispersion PD-3 (magenta)]
Pigment dispersion PD-3 having a pigment concentration of 16% by mass was obtained in the same manner as pigment dispersion PD-1, except that the carbon black was changed to Pigment Red 122 Toner Magenta EO02 (manufactured by Clariant).

[Pigment dispersion PD-4 (yellow)]
A pigment dispersion PD-4 having a pigment concentration of 16% by mass was obtained in the same manner as the pigment dispersion PD-1, except that the carbon black was changed to the first yellow 531 of Pigment Yellow 74 (manufactured by Dainichi Seika). It was.

[Ink I-1]
25.00 parts pigment dispersion PD-2, 40.00 parts 3-ethyl-3-hydroxymethyloxetane, 2.00 parts silicone surfactant TEGO Wet 270 (manufactured by Sakai Kogyo Co., Ltd.) and 33.00 A portion of ion-exchanged water was mixed and stirred for 1 hour, and then filtered through a membrane filter having a pore size of 1.2 μm to obtain ink I-1.

[Ink I-2]
4.00 parts of dye (cyan) Project Fast Cyan 2 (manufactured by Zeneca), 40.00 parts of 3-ethyl-3-hydroxymethyloxetane and 56.00 parts of ion-exchanged water were mixed and stirred for 1 hour. Then, it filtered with the membrane filter whose pore diameter is 1.2 micrometers, and obtained the ink I-2.

[Ink I-3]
50.00 parts pigment dispersion PD-1, 30.00 parts 3-ethyl-3-hydroxymethyloxetane, 2.00 parts silicone surfactant TEGO Wet 270 (manufactured by Sakai Kogyo Co., Ltd.) and 18.00 A portion of ion-exchanged water was mixed and stirred for 1 hour, and then filtered through a membrane filter having a pore size of 1.2 μm to obtain ink I-3.

[Ink I-4]
Ink I-4 was obtained in the same manner as Ink I-3 except that Pigment Dispersion PD-1 was changed to Pigment Dispersion PD-3.

[Ink I-5]
25.00 parts Pigment Dispersion PD-4, 20.00 parts 3-ethyl-3-hydroxymethyloxetane, 20.00 parts 1,3-butanediol, 2.00 parts silicone surfactant TEGO Wet 270 (manufactured by Sakai Kogyo Co., Ltd.) and 33.00 parts of ion exchange water were mixed and stirred for 1 hour, and then filtered through a membrane filter having a pore size of 1.2 μm to obtain ink I-5.

[Ink I-6]
Ink I- except that the addition amounts of pigment dispersion PD-2, 3-ethyl-3-hydroxymethyloxetane and ion-exchanged water were changed to 20.00 parts, 10.00 parts and 68.00 parts, respectively. In the same manner as in Example 1, ink I-6 was obtained.

[Ink I-7]
Ink I except that 40.00 parts of 3-ethyl-3-hydroxymethyloxetane was changed to 20.00 parts of 1,3-butanediol and the amount of ion-exchanged water added was changed to 53.00 parts. Ink 1-7 was obtained in the same manner as in Example-1.

[Ink I-8]
Ink I-8 was obtained in the same manner as Ink I-1, except that the addition amounts of 3-ethyl-3-hydroxymethyloxetane and ion-exchanged water were changed to 50.00 parts and 23.00 parts, respectively. It was.

[Ink I-9]
Ink I- except that the addition amounts of pigment dispersion PD-2, 3-ethyl-3-hydroxymethyloxetane and ion-exchanged water were changed to 30.00 parts, 65.00 parts and 3.00 parts, respectively. In the same manner as in No. 1, ink I-9 was obtained.

  Next, the viscosity of the ink was measured.

<Viscosity>
The viscosity of the ink was measured at 25.0 ° C. using a rotational viscometer RE80L / cone plate type (manufactured by Toki Sangyo Co., Ltd.). Specific operations are shown below. 1.1 mL of ink was collected and placed in a viscometer sample cup. Next, the sample cup was attached to the main body of the viscometer and allowed to stand for 1 minute, and then the viscometer rotor was rotated to read the value after 1 minute. At this time, the rotation speed of the rotor was adjusted so that the torque was constant within a range of 40 to 80%.

  Table 1 shows the measurement results of the viscosity of the ink.

［樹脂エマルジョンＰ−１（シリコン変性アクリル樹脂）］
機械式攪拌機、温度計、窒素ガス導入管、還流管及び滴下ロートを備えたフラスコ内を十分に窒素ガスで置換した後、純水１００ｇ、ドデシルベンゼンスルホン酸ナトリウム３ｇとポリエチレングリコールノニルフェニルエーテル１ｇを仕込み、過硫酸アンモニウム１ｇ、亜硫酸水素ナトリウム０．２ｇを添加し、６０℃に昇温した。次に、アクリル酸ブチル３０ｇ、メタクリル酸メチル４０ｇ、メタクリル酸ブチル１９ｇ、ビニルシラントリオールカリウム塩１０ｇと３−メタクリロイルオキシプロピルメチルジメトキシシラン１ｇの混合物を３時間かけてフラスコ内に滴下して重合し、樹脂エマルジョンＰ−１を得た。このとき、重合反応液のｐＨが７となるようアンモニア水溶液で調整して重合した。マイクロトラックＵＰＡを用いて測定した樹脂エマルジョンＰ−１の平均粒子径は１６０ｎｍであった。また、樹脂エマルジョンＰ−１の固形分濃度は３０質量％であった。

[Resin emulsion P-1 (silicon modified acrylic resin)]
After fully replacing the inside of the flask equipped with a mechanical stirrer, thermometer, nitrogen gas inlet tube, reflux tube and dropping funnel with nitrogen gas, 100 g of pure water, 3 g of sodium dodecylbenzenesulfonate and 1 g of polyethylene glycol nonylphenyl ether were added. First, 1 g of ammonium persulfate and 0.2 g of sodium hydrogen sulfite were added, and the temperature was raised to 60 ° C. Next, a mixture of 30 g of butyl acrylate, 40 g of methyl methacrylate, 19 g of butyl methacrylate, 10 g of vinylsilanetriol potassium salt and 1 g of 3-methacryloyloxypropylmethyldimethoxysilane was dropped into the flask over 3 hours to polymerize the resin. Emulsion P-1 was obtained. At this time, the polymerization reaction liquid was polymerized by adjusting with an aqueous ammonia solution so that the pH was 7. The average particle size of the resin emulsion P-1 measured using Microtrac UPA was 160 nm. Moreover, the solid content concentration of the resin emulsion P-1 was 30% by mass.

[Coating liquid A-1]
70.0 parts of a polyethylene (PE) wax emulsion AQUACER 531 (manufactured by Big Chemie Japan) having a non-volatile content of 35% by mass and 30.0 parts of resin emulsion P-1 were mixed and stirred for 1 hour to obtain coating solution A. -1 was obtained. Here, the PE wax has a melting point of 130 ° C.

[Coating liquid A-2]
PE wax emulsion AQUACER 531 (manufactured by Big Chemie Japan) was used as the coating liquid A-2.

[Coating liquid A-3]
A coating liquid A-3 was obtained in the same manner as the coating liquid A-1, except that the PE wax emulsion was changed to a modified paraffin wax emulsion AQUACER 537 (manufactured by Big Chemie Japan) having a nonvolatile content of 30% by mass. Here, the modified paraffin wax has a melting point of 110 ° C.

[Coating liquid A-4]
A coating liquid A-4 was obtained in the same manner as the coating liquid A-1, except that the PE wax emulsion was changed to a modified polypropylene (PP) wax emulsion AQUACER 593 (produced by Big Chemie Japan) having a nonvolatile content of 30% by mass. . Here, the modified PP wax has a melting point of 160 ° C.

  Table 2 shows the characteristics of the coating solution.

（実施例１）
２３℃、５０％ＲＨの環境下で、インクジェットプリンターＩＰＳｉＯ ＧＸ５０００（リコー社製）にインクＩ−１を充填した。次に、Ｍｉｃｒｏｓｏｆｔ Ｗｏｒｄ２０００（Ｍｉｃｒｏｓｏｆｔ社製）で作成した６４ｐｏｉｎｔ及び１２８ｐｏｉｎｔのＪＩＳ Ｘ ０２０８（１９９７），２２２３の一般記号が記載されているチャートを印字するために、記録媒体にインクＩ−１を塗布した。このとき、印字モードを、プリンタに添付されているドライバにおける、光沢紙のユーザー設定より「光沢紙−標準きれい」モードを「色補正なし」に改変したモード又は「光沢紙−標準はやい」モードを「色補正なし」に改変したモードとした。また、記録媒体として、ルミアートグロス９０ｇｓｍ（ＭＯＮＤＩカラー・コピー社製）（以下、コート紙１という）又は坪量が７３．３ｇ／ｃｍ^２のＯＫトップコート＋（王子製紙社製）（以下、コート紙２という）を用いた。さらに、ＪＩＳ Ｘ ０２０８（１９９７），２２２３の一般記号は、外形が正方形であり、全面が塗りつぶされている記号である。

Example 1
Ink I-1 was filled in an ink jet printer IPSiO GX5000 (manufactured by Ricoh Co., Ltd.) in an environment of 23 ° C. and 50% RH. Next, ink I-1 was applied to a recording medium in order to print a chart containing general symbols of 64 points and 128 points of JIS X 0208 (1997), 2223 created by Microsoft Word 2000 (manufactured by Microsoft). . At this time, the printing mode is changed to a mode in which the “glossy paper-standard clean” mode is changed to “no color correction” or “glossy paper-standard fast” mode from the user setting of glossy paper in the driver attached to the printer. The mode was changed to “no color correction”. Further, as a recording medium, Lumiart gloss 90 gsm (manufactured by MONDI Color Copy) (hereinafter referred to as coated paper 1) or OK top coat having a basis weight of 73.3 g / cm ² + (manufactured by Oji Paper Co., Ltd.) Coated paper 2) was used. Furthermore, the general symbols of JIS X 0208 (1997), 2223 are symbols whose outer shape is square and whose entire surface is filled.

  Ten seconds after printing was completed, the recording medium was heated by applying warm air for 1 minute using a dryer. At this time, the wind speed of the dryer was set to 20 m / s. As a result, the temperature of the recording medium during heating was 100 ° C. The temperature of the recording medium during heating was measured by bringing a K-type thermocouple (manufactured by Three High) having a wire diameter of 0.2 mm into contact with the recording medium.

  Further, one minute after the heating is finished, the compressed air and the coating liquid A-1 are sent to the mini atomizing nozzle MMA-10 (manufactured by Everloy Corporation), which is a two-fluid nozzle, as a spray nozzle, and vertically from the recording medium. The coating liquid A-1 was applied to the printing surface of the recording medium from a position 30 cm away. At this time, the scanning speed of the spray nozzle was adjusted so that the coating amount of the coating liquid A-1 was 100 mg per A4 size.

  Two minutes after applying the coating liquid A-1, recording is performed on a hot plate NINOS ND-2 (manufactured by ASONE) preheated to 100 ° C. so that the non-printing surface contacts the top plate of the hot plate. A medium was set up, and a hot air was applied to the recording medium for 1 minute using a dryer to form an image. At this time, the wind speed of the dryer was set to 20 m / s. As a result, the temperature of the recording medium during heating was 100 ° C.

(Example 2)
In the heating of the recording medium after applying the coating liquid A-1, the air speed of the dryer and the heating of the hot plate were weakened, and the temperature of the recording medium being heated was adjusted to 60 ° C. Example 1 In the same manner, an image was formed.

(Example 3)
In the heating of the recording medium after the coating liquid A-1 was applied, Example 1 was performed except that the wind speed of the dryer and the heating of the hot plate were increased and the temperature of the recording medium being heated was adjusted to 160 ° C. In the same manner, an image was formed.

(Examples 4 to 11)
An image was formed in the same manner as in Example 1 except that the inks I-2 to I-9 were used in place of the ink I-1.

(Examples 12 to 14)
An image was formed in the same manner as in Example 1 except that the coating liquids A-2 to A-4 were used instead of the coating liquid A-1.

(Example 15)
As a spray nozzle, a one-fluid nozzle holocorn atomizing nozzle KSN-4A (Everloy Shoji Co., Ltd.) was used, and only the coating liquid A-1 was fed to the spray nozzle. Formed.

(Example 16)
An image was formed in the same manner as in Example 1 except that in the heating of the recording medium after applying the coating liquid A-1, only a hot plate was used without using a dryer. The temperature of the recording medium during heating was 100 ° C.

(Example 17)
An image was formed in the same manner as in Example 1 except that in the heating of the recording medium after the coating liquid A-1 was applied, only a dryer was used without using a hot plate. The temperature of the recording medium during heating was 100 ° C.

(Example 18)
An image was formed in the same manner as in Example 1 except that the recording medium was not heated before applying the coating liquid A-1.

(Comparative Example 1)
An image was formed in the same manner as in Example 1 except that the coating liquid A-1 was not applied.

(Comparative Example 2)
An image was formed in the same manner as in Example 1 except that the coating liquid A-1 was not heated after being applied.

  Table 3 shows image forming conditions of the example and the comparative example.

なお、第一の加熱及び第二の加熱は、それぞれ塗布液を塗布する前の記録媒体の加熱及び塗布液を塗布した後の記録媒体の加熱を意味する。

The first heating and the second heating mean heating of the recording medium before applying the coating liquid and heating of the recording medium after applying the coating liquid, respectively.

  Next, image density, image glossiness, fixability and blocking resistance were evaluated.

<Image density>
Using X-Rite 938 (manufactured by X-Rite Co., Ltd.), the image density of an area where a general symbol of 64 points on the recording medium was printed was measured. At this time, the print mode is set to a mode in which the “glossy paper-standard clean” mode is changed to “no color correction” from the glossy paper user setting in the driver attached to the printer, and the coated paper 1 is used as a recording medium. Using.

  The image density was determined according to the following evaluation criteria.

[Evaluation criteria]
Black ink AA: 2.00 or more A: 1.90 or more and less than 2.00 B: 1.80 or more and less than 1.90 C: less than 1.80 Cyan ink AA: 2.00 or more A: 1.90 or more 2. Less than 00 B: 1.80 or more and less than 1.90 C: Less than 1.80 Magenta ink AA: 1.90 or more A: 1.80 or more and less than 1.90 B: 1.70 or more and less than 1.80 C: 1. Less than 70 Yellow ink AA: 1.00 or more A: 0.90 or more and less than 1.00 B: 0.80 or more and less than 0.90 C: Less than 0.80 <Image Glossiness>
Using a handy gloss meter PC-IIM type (manufactured by Nippon Denshoku Industries Co., Ltd.), the 60 ° glossiness of an area where a 128 point general symbol was printed on the recording medium was measured. At this time, the print mode is set to a mode in which the “glossy paper-standard clean” mode is changed to “no color correction” from the glossy paper user setting in the driver attached to the printer, and the coated paper 1 is used as a recording medium. Using.

  The image gloss was determined according to the following evaluation criteria.

〔Evaluation criteria〕
AA: 30 or more A: 25 or more and less than 30 B: 20 or more and less than 25 C: Less than 20 <Fixability 1>
The area on which the general symbol of 128 points JIS X 0208 (1997), 2223 is printed is the same as the recording medium used for printing, and is not printed by rubbing 10 times with an unprinted recording medium. The degree of transfer of the pigment onto the recording medium was visually observed to evaluate the fixability. At this time, the print mode is set to a mode in which the “glossy paper-standard clean” mode is changed to “no color correction” from the glossy paper user setting in the driver attached to the printer, and the coated paper 1 is used as a recording medium. Using.

  Fixability was determined according to the following evaluation criteria.

〔Evaluation criteria〕
A: Little transfer of pigment to the recording medium is observed B: Slight transfer of pigment to the recording medium is observed (area less than 10% of the whole)
C: Transfer of the pigment to the recording medium is clearly seen (area of 10% or more of the whole)
<Fixability 2>
Fixability was evaluated in the same manner as Fixability 1 except that coated paper 2 was used as the recording medium.

<Fixability 3>
The print mode is the same as Fixability 1 except that the glossy paper user setting in the driver attached to the printer is changed to the “Glossy paper-Standard fast” mode is changed to “No color correction”. Fixability was evaluated.

<Blocking resistance 1>
An area on which a general symbol of 128 points JIS X 0208 (1997), 2223 is printed is the same as the recording medium used for printing 3 minutes after the image is formed, and is not printed (4 cm × 4 cm) were stacked, and a rubber sheet measuring 2 cm in length, 2 cm in width, and 0.2 cm in thickness was placed on the center of the recording medium. Next, a weight was placed on the rubber sheet so that the pressure applied to the recording medium from the rubber sheet was 0.5 kgf / cm ^2, and left for 12 hours in an environment of 23 ° C. and 50% RH. Further, the stacked recording media were peeled off, and the transfer state of the pigment to the recording media not printed was visually observed to evaluate the blocking resistance. At this time, the print mode is set to a mode in which the “glossy paper-standard clean” mode is changed to “no color correction” from the glossy paper user setting in the driver attached to the printer, and the coated paper 1 is used as a recording medium. Using.

  The blocking resistance was determined according to the following evaluation criteria.

〔Evaluation criteria〕
A: Transfer of the pigment to the recording medium is hardly observed.

B: Slight transfer of the pigment to the recording medium is observed (less than 10% of the total area)
C: Transfer of the pigment to the recording medium is clearly seen (area of 10% or more of the whole)
<Blocking resistance 2>
The blocking resistance was evaluated in the same manner as blocking resistance 1 except that coated paper 2 was used as the recording medium.

  Table 4 shows the evaluation results of image density, image glossiness, fixability and blocking resistance.

表４から、実施例１〜１８は、コート紙に画像濃度、画像光沢度、定着性及び耐ブロッキング性に優れる画像を形成できることがわかる。

From Table 4, it can be seen that Examples 1 to 18 can form images excellent in image density, image glossiness, fixability and blocking resistance on coated paper.

  On the other hand, since Comparative Example 1 does not apply the coating liquid A-1, the image density, the image glossiness, the fixing property, and the blocking resistance of the image formed on the coated paper are inferior.

  In Comparative Example 2, since the coating liquid A-1 is not heated after being applied, the fixability at the time of high-speed printing of the image formed on the coated paper 1 and the fixing at the time of normal printing of the image formed on the coated paper 2 Inferior property and blocking resistance.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Liquid discharge head 20 Spray coating apparatus 21 Sprayer 22 Hot air generator 23 Temperature detection means 30 Liquid supply device 110, 160 Roller 120, 140 Hot air apparatus 130, 150 Heating roller 211 Liquid introduction path 212 Gas introduction path 213 nozzle

JP 2012-213906 A

Claims (9)

A step of discharging a liquid containing a coloring material and water onto a recording medium;
Spraying a coating liquid containing wax on the surface of the recording medium from which the liquid has been discharged;
An image forming method comprising a step of heating a recording medium on which the coating liquid is spray-coated.   2. The image forming method according to claim 1, wherein the recording medium on which the coating liquid is spray-coated is heated so that the temperature becomes 0.45 times or more and 1.25 times or less of the melting point of the wax.   3. The image forming method according to claim 1, wherein hot air is applied to the recording medium when the recording medium on which the coating liquid is spray-coated is heated.   The image forming method according to claim 1, wherein the coating liquid is applied by spraying using a two-fluid nozzle. Further comprising heating the recording medium from which the liquid has been ejected,
5. The image forming method according to claim 1, wherein the coating liquid is spray-coated on a surface of the heated recording medium on which the liquid is ejected. 6.   The image forming method according to claim 1, wherein the color material is a pigment.   The image forming method according to claim 1, wherein the coating liquid further contains a resin.   The image forming method according to claim 1, wherein the liquid has a viscosity at 25.0 ° C. of 5 mPa · s to 15 mPa · s. Liquid ejection means for ejecting a liquid containing a color material and water to a recording medium;
Spray coating means for spray-coating a coating liquid containing wax on the surface of the recording medium on which the liquid is discharged;
An image forming system comprising heating means for heating a recording medium on which the coating liquid is spray-coated.

Images