JP2020175665A - Image formation device and image formation method - Google Patents

Abstract

To provide an image formation method excellent in fixability and blocking resistance.SOLUTION: An image formation method has steps of: applying first liquid used for image formation onto a discharge object from a liquid discharge head; and spraying, by a spray device, second liquid containing a nonvolatile component together with gas at 50°C or higher and 350°C or lower, onto the surface on the side where the first liquid is applied of the discharge object.SELECTED DRAWING: Figure 1

Description

The present invention relates to an image forming method, a spraying device, and an image forming device.

Compared with other recording methods, the inkjet recording method has advantages that the process is simple, full-color conversion is easy, and an image with high resolution can be obtained even with a device having a simple configuration. As a result, it has become widespread and is expanding from personal to office applications, commercial printing and industrial printing.

In the fields 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 high image density, high image gloss is used. Degree and high fixability are required.

With the development of the inkjet recording method in the fields of commercial printing and industrial printing, productivity is required and the printing speed is increasing year by year. In addition, water-based inks are often used because of their safety, ease of handling, and consideration for the environment.

Generally, when printing at high speed by an inkjet method using a water-based ink, the organic solvent containing water in the ink permeates the paper slowly, so that the organic solvent containing water remains on the surface of the recording medium. The image was lost due to transfer or scratching, and there was a problem in fixability. Further, in the case of paper having a small basis weight, there is also a problem of paper deformation due to the difference in paper expansion / contraction ratio between the printed portion and the non-printed portion.

As an example of a method for solving such a problem, a resin-coated pigment in which at least a part of the pigment particles is coated with a water-insoluble resin, resin particles, wax particles, 1,2-alkylene diol, polyhydric alcohol, and pyrrolidone derivative. An ink application step of applying an ink composition containing an acetylene glycol-based surfactant from an ejection head to a recording medium, and an ink application step in which the movement speed in the sub-scanning direction between the ejection head and the recording medium is set to 200 mm / sec or more. A drying step of drying the recording medium to which the ink is applied and a step of adhering the dried recording medium with 1 to 1000 mg / m ² of a powder having an average particle diameter of 1 to 100 μm are provided and accumulated. An image forming method including an integration step is disclosed (see, for example, Patent Document 1).

However, the disclosed image forming method focuses only on scratch resistance (fixability), and there is room for improvement in improving blocking resistance.

An object of the present invention is to provide an image forming method having excellent fixing property and blocking resistance.

In this image forming method, a step of applying a first liquid used for image formation to a discharge target object by a liquid discharge head and a surface of the discharge target object on the side on which the first liquid is applied are applied. It is a requirement to have a step of spraying a second liquid containing a non-volatile component together with a gas of 50 ° C. or higher and 350 ° C. or lower by a spraying device.

According to the disclosed technique, it is possible to provide an image forming method having excellent fixing property and blocking resistance.

It is a schematic diagram explaining the image forming apparatus and the image forming method which concerns on this Embodiment. It is a schematic diagram explaining the spraying apparatus which concerns on this embodiment.

Hereinafter, modes for carrying out the invention will be described with reference to the drawings. In each drawing, the same components may be designated by the same reference numerals and duplicate description may be omitted.

The image forming method according to the present embodiment includes a step of applying the first liquid used for image formation to the discharge target object by the liquid discharge head, and a side on which the first liquid of the discharge target object is applied. The surface has a step of spraying a second liquid containing a non-volatile component together with a gas of 50 ° C. or higher and 350 ° C. or lower by a spraying device.

Here, the first liquid used for image formation is, for example, an ink containing a coloring material and water. The second liquid is a coating liquid sprayed by a spraying device. The object to be ejected is, for example, a recording medium such as coated paper.

Hereinafter, the first liquid will be described as an ink containing a coloring material and water, the second liquid as a coating liquid, and the discharge target as a recording medium such as coated paper. The first liquid is used for image formation. It may be a liquid and is not limited to ink containing a coloring material and water. Further, the ejection target is not limited to a recording medium such as coated paper as long as it is an object on which an image is formed.

By applying a coating liquid containing a non-volatile component together with a gas of 50 ° C. or higher and 350 ° C. or lower to the surface of the recording medium on the side where the ink is applied by a spraying device, the non-volatile component is before adhering to the recording medium. Drying of the spray droplets of the coating liquid containing the above progresses, and the non-volatile components are uniformly arranged on the surface layer of the surface on the side where the ink of the recording medium is applied.

In addition, the gas (warm air) of 50 ° C. or higher and 350 ° C. or lower ejected from the spray device promotes the drying of the ink near the surface layer of the surface on the side where the ink of the recording medium is applied, and the non-volatile component is inside the ink layer. Prevent intrusion.

The non-volatile components uniformly arranged on the surface layer without entering the inside of the ink layer can protect the image formed by the ink.

Further, the coating liquid containing the non-volatile component wets the non-printed portion thinly and evenly, so that the difference in expansion and contraction between the printed portion and the non-printed portion is reduced. As a result, it is possible to form an image having excellent image density, image glossiness, fixability and blocking resistance on the coated paper and having a small amount of paper deformation.

As described above, in the image forming method according to the present embodiment, it is possible to realize an image forming method capable of improving the protection performance (for example, fixability, blocking resistance, etc.) against the ink applied to the recording medium.

Hereinafter, the image forming method according to the present embodiment will be described in detail.

<Non-volatile component>
The non-volatile component includes powder and wax.

<Powder>
In the present embodiment, the powdery substance refers to a powdery solid or a granular solid having an average particle diameter of about 0.01 μm to 1000 μm.

The material constituting the powder is not particularly limited, but any inorganic material such as metal, metal oxide, ceramic or silica and an organic material such as resin, cellulose or rubber can be used.

The powdery substance is not particularly limited, but is preferably one that disperses in water without precipitating. As a method for dispersing the powder in water, at least one method of bonding an atomic group or a resin containing at least one anionic hydrophilic group, a nonionic hydrophilic group, and a cationic hydrophilic group to the surface of the powder. A method of coating with a resin containing an anionic hydrophilic group, a nonionic hydrophilic group, and a cationic hydrophilic group, and a method of dispersing with a dispersant containing at least one anionic hydrophilic group, a nonionic hydrophilic group, and a cationic hydrophilic group. Can be mentioned.

It is preferable to use a resin as the powder, and by using the resin as the powder, the image density, image glossiness, fixability and blocking resistance of the image formed on the coated paper are further improved. Can be done.

The wax exhibiting water dispersibility, which will be described later, can be regarded as being contained in the powder, but in the present embodiment, for convenience, the wax exhibiting water dispersibility is contained in the wax, not in the powder. Treat as a thing.

<Wax>
The wax is not particularly limited, but a wax exhibiting water solubility (hereinafter referred to as water-soluble wax) or a wax exhibiting water dispersibility (hereinafter referred to as water-dispersible wax) 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. As the water-dispersible wax, it can be mainly used as a wax emulsion.

Specific examples of the water-soluble wax or the water-dispersible wax include carnauba wax, candelilla wax, honey wax, rice wax, lanolin and other plants, animal wax, paraffin wax, microcrystalin wax, polyethylene wax, polypropylene wax, and oxidation. Petroleum wax such as polyethylene wax and petrolatum, mineral wax such as montan wax and ozokerite, synthetic wax such as carbon wax, hexto wax, polyethylene wax and stearic acid amide, α-olephine / maleic anhydride copolymer, etc. Natural / synthetic wax emulsions, compounded waxes, etc. can be used alone or in admixture. Further, as the water-soluble wax or the water-dispersible wax, latex, colloidal solution, suspension and the like can also be used.

Commercially available waxes can also be used, and specific examples thereof include serosol 524 (carnauba wax having a melting point of 83 ° C. and a particle size of 200 nm) (manufactured by Chukyo Yushi Co., Ltd.) and HYTEC E-6500 (manufactured by Chukyo Yushi Co., Ltd.). 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 (manufactured by Toho Chemical Co., Ltd.) Polypropylene wax with a melting point of 156 ° C and a particle size of 60 nm (manufactured by Toho Chemical Co., Ltd.), Nopcoat PEM-177 (polyethylene wax having a melting point of 105 ° C and a particle size of 10 nm) (manufactured by Sannopco), AQUACER® 498 (Parental wax with a melting point of 58 ° C) (manufactured by Big Chemie Japan), AQUACER (registered trademark) 535 (mixed wax with a melting point of 95 ° C) (manufactured by Big Chemie Japan), AQUACER (registered trademark) 531 (melting point) (Polyethylene wax with a melting point of 130 ° C and a particle size of 123 nm) (manufactured by Big Chemie Japan), AQUACER (registered trademark) 515 (polyethylene wax with a melting point of 135 ° C and a particle size of 33 nm) (manufactured by Big Chemie Japan), etc. Be done.

<Color material>
The coloring material is not particularly limited, but pigments and dyes can be used. Among these, pigments are preferable from the viewpoint of image density and glossiness of the image formed on the coated paper.

The pigment is not particularly limited, but a pigment having at least one anionic hydrophilic group on the surface and exhibiting water dispersibility or water solubility is preferable. Examples of the water-dispersible or water-soluble pigment include a pigment dispersed with a dispersant having at least one anionic hydrophilic group (1) and a pigment coated with a resin having at least one anionic hydrophilic group (1). 2), an atomic group containing at least one anionic hydrophilic group, at least one anionic hydrophilic group, or a pigment (3) to which a resin having at least one anionic hydrophilic group is bonded can be mentioned.

The pigment (1) is generally called a surfactant-dispersed pigment or a resin-dispersed pigment, and the dispersant takes charge of the interface between the pigment and water so that the pigment is dispersed in water.

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

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

The pigment is not particularly limited and may be appropriately selected depending on the intended purpose. For example, either an inorganic pigment or an organic pigment may be used. These may be used alone or in combination of two or more.

Examples of the inorganic pigment include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, dark blue, cadmium red, chrome yellow, metal powder, carbon black and the like. Among these, carbon black is preferable. Examples of carbon black include those manufactured by known methods such as a contact method, a furnace method, and a thermal method.

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

Examples of the azo pigment include azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments and the like. Examples of the polycyclic pigment include phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinofuralone pigments, and Rhodamine B lake pigments. Examples of the dye chelate include a basic dye type chelate and an acid dye type chelate.

Examples of black pigments include carbon blacks (CI pigment black 7) such as furnace black, lamp black, acetylene black, and channel black, copper, iron (CI pigment black 11), and titanium oxide. Examples thereof include metals such as aniline black (CI pigment black 1) 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 preferable.

A commercially available product can be used as carbon black. As a commercially available product, for example, 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 Colombia); Regal400R, 330R, 660R, Morgan L, Monarch (registered) Trademarks) 700, 800, 880, 900, 1000, 1100, 1300, Monarch (registered trademark) 1400 (all manufactured by Cabot); 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), etc. Can be mentioned.

The pigment for color that can be used for yellow ink is not particularly limited and may be appropriately selected depending on the intended purpose. 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. Pigment Yellow 180 and the like.

The color pigment that can be used for magenta ink is not particularly limited and may be appropriately selected depending on the intended purpose. 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.

The pigment for color and which can be used for cyan ink is not particularly limited and may be appropriately selected depending on the intended purpose. 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. Bat blue 60 and the like can be mentioned.

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 well-balanced ink having excellent color tone and light resistance can be obtained. be able to.

<Water>
Examples of water include pure water such as ion-exchanged water, ultrafiltered water, reverse osmosis water, and distilled water, high pure water, and ultrapure water. The content of water in the ink is preferably 20 to 60% by mass.

<Ink>
Inks include, in addition to coloring materials and water, organic solvents, surfactants, resins, pH regulators, antiseptic and fungicides, rust inhibitors, antioxidants, UV absorbers, oxygen absorbers, as needed. It may further contain a light stabilizer and the like.

In the production of ink, it is preferable to mix the constituent components and then filter the coarse particles using a filter, a centrifuge, or the like to degas. When the ink is applied to the recording medium by the liquid ejection head (applied by the inkjet method), an image forming apparatus described later can be used.

<Coating liquid>
The coating liquid contains a non-volatile component. As the coating liquid, a powdery aqueous dispersion or a wax emulsion can be used. The coating liquid preferably contains wax. Since the coating liquid contains wax, the image density, image glossiness, fixability and blocking resistance of the image formed on the coated paper can be further improved.

The resin emulsion is not particularly limited, but an acrylic resin emulsion, a polyurethane emulsion, a styrene-acrylic resin emulsion, an acrylic-silicone resin emulsion, and a fluororesin emulsion can be used.

Commercially available polyurethane emulsions include SF460, SF460S, SF420, SF110, SF300, SF361 (manufactured by Nippon Unicar), Bondic series (manufactured by DIC), Takelac W, WS series, W5025, W5661 (manufactured by Mitsui Chemicals). And so on.

Commercially available styrene-acrylic resin emulsions include J-450, J-734, J-7600, J-352, J-390, J-7100, J-741, J74J, J-511, J-840, Examples thereof include J-775, HRC-1645, HPD-71 (all manufactured by Johnson Polymer Co., Ltd.) and the like.

Examples of commercially available acrylic-silicone resin emulsions include UVA383MA (manufactured by BASF) and AP4710 (manufactured by Showa High Polymer Co., Ltd.).

Examples of commercially available fluororesin emulsions include FE4300, FE4500, and FE4400 (all manufactured by Asahi Glass Co., Ltd.).

A wax emulsion and a resin emulsion can be mixed and used as the coating liquid.

The coating liquid further contains an organic solvent, a surfactant, a pH adjuster, an antiseptic / antifungal agent, a rust preventive, an antioxidant, an ultraviolet absorber, an oxygen absorber, a light stabilizer and the like, if necessary. It may be.

When applying the coating liquid to the recording medium, a spraying device described later can be used.

<Image forming device, image forming method>
The image forming apparatus according to the present embodiment sprays a liquid ejection head for applying an ink containing a coloring material and water to a recording medium and a coating liquid containing a non-volatile component together with a gas at 50 ° C. or higher and 350 ° C. or lower for recording. It has a spraying device that applies the ink of the medium to the surface on which the ink is applied. The image forming apparatus according to the present embodiment may further include other means selected as appropriate, such as a transporting means, a drying means, a control means, and the like, if necessary.

FIG. 1 is a schematic diagram illustrating an image forming apparatus and an image forming method according to the present embodiment. The image recording device 1 illustrated in FIG. 1 is an inkjet recording device, and has a liquid discharge head 10 and a spray device 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 and the heating roller 130, the spray device 20, the liquid supply device 30, and the hot air device 140 And the heating roller 150 are arranged.

In order to form an image using the image forming apparatus 1, first, an ink containing a coloring material and water is placed on a recording medium 300 such as coated paper that is unwound from an unwinding roller 110 and conveyed in the direction of an arrow. 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, the formed image is dried by contact between the warm air sent from the hot air device 120 and the heating roller 130. Then, the coating liquid containing the non-volatile component is sprayed by the spraying device 20 together with the gas (warm air) having a predetermined temperature or higher, and is applied to the surface of the recording medium 300 on the side to which the ink is applied. The coating liquid is supplied from the liquid supply device 30 to the spray device 20. Details of the spray device 20 and the liquid supply device 30 will be described later.

After that, the image is dried again by the warm air sent from the warm air device 140 and the heating roller 150 (fixing step), the recording medium 300 is wound by the winding roller 160, and the formation of the image is completed. The hot air devices 120 and 140 and the heating rollers 130 and 150 are not essential configurations.

In the example of FIG. 1, a coating liquid containing a non-volatile component is sprayed by a spraying device 20 together with a gas (warm air) having a temperature equal to or higher than a predetermined temperature, and is applied to the surface of the recording medium 300 on the side to which the ink is applied. A heating step for heating the recording medium 300 is provided both before and after. However, the heating step may be provided only before or after the step of applying by the spraying device 20.

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

[Liquid discharge head]
The liquid ejection head 10 is a means for applying a stimulus to the ink to eject it. The stimulus is not particularly limited and may be appropriately selected depending on the intended purpose, and examples thereof include heat (temperature), pressure, vibration, and light. These may be used alone or in combination of two or more. Among these, heat and pressure are preferable.

Specific examples include piezoelectric actuators such as piezoelectric elements, thermal actuators that utilize phase changes due to film boiling of liquids using electrothermal conversion elements such as heat-generating resistors, and shape memory alloy actuators that use metal phase changes due to temperature changes. Examples thereof include an electrostatic actuator that uses an electrostatic force.

The mode of ink flight is not particularly limited and varies depending on the type of stimulus and the like. For example, as a mode of ink flight when the stimulus is heat, thermal energy corresponding to the recording signal is applied to the ink in the liquid ejection head 10 by using, for example, a thermal head, and the thermal energy is used. Examples thereof include a method in which bubbles are generated in the ink and the ink is ejected as droplets from the nozzle hole of the liquid ejection head 10 by the pressure of the bubbles.

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

In the example of FIG. 1, the liquid discharge head 10 is a full-line type head, and is black (K), cyan (C), magenta (M), and yellow (Y) from the upstream side in the transport direction of the recording medium 300. It is configured by arranging four heads K, C, M, and Y corresponding to the above.

[Spray device]
FIG. 2 is a schematic view illustrating a spraying device according to the present embodiment. As shown in FIG. 2, the spraying device 20 includes a sprayer 21 and a warm air generator 22.

The sprayer 21 introduces a liquid introduction path 211 into which the coating liquid is introduced from a liquid supply device 30 provided outside the spraying device 20 and a gas introduction into which a gas (warm air) having a predetermined temperature is introduced from the warm air generator 22. The path 212 is provided with 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.

The warm air generator 22 is a device that generates a gas (warm air) having 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, nitrogen, or the like. 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 detecting means 23 may be provided outside the vicinity of the end portion of the gas introduction path 212 on the nozzle 213 side. In this case, the temperature detecting 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 warm air generator 22. As the temperature detecting means 23, for example, a thermocouple can be used.

The warm air generator 22 controls the temperature of the gas introduced into the gas introduction path 212 based on the detection result of the temperature detecting 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 detecting means 23 is 50 ° C. or higher and 350 ° C. or lower.

The temperature detected by the temperature detecting means 23 and the actual gas (atmosphere) temperature may differ depending on the system configuration. If the temperature is in equilibrium near the temperature detecting means 23 connected to the gas introduction path 212, the temperature detected by the temperature detecting means 23 becomes the atmospheric temperature of the gas. However, depending on the installation location of the temperature detecting means 23, it is assumed that there is a temperature difference between the temperature detected by the temperature detecting means 23 and the actual atmospheric temperature of the gas. In this case, it goes without saying that the temperature is controlled by the warm air generator 22 in consideration of the temperature difference.

When the temperature detecting means 23 is not provided, the temperature difference between the temperature of the gas generated by the warm 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 to obtain the temperature. The wind generator 22 may generate a gas having a temperature in consideration of 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 50 ° C., the hot air generator 22 generates a gas of 55 ° C. , It may be introduced into the gas introduction path 212.

The liquid supply device 30 introduces the coating liquid containing the volatile component into the liquid introduction path 211 at a predetermined liquid feeding amount. As a method for introducing (sending) the coating liquid into the liquid introduction path 211 by the liquid supply device 30, for example, a pressure method in which the coating liquid is sent by a pump or a pressure tank, or a siphon method in which the liquid is sent by utilizing the suction effect of gas. And so on.

In the example of FIG. 2, the liquid supply device 30 is provided as a separate body from the spray device 20, but the liquid supply device 30 may be incorporated into the spray device 20. In this case, the spraying device 20 has a spraying device 21, a warm air generator 22, and a liquid supply device 30.

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

In FIG. 2, 300 indicates a recording medium, and 310 indicates ink applied to the recording medium 300 by the liquid ejection head. The recording medium 300 is, for example, roll paper and can be conveyed in the direction of the arrow.

The spraying device 20 mixes the coating liquid containing the non-volatile component introduced into the liquid introduction path 211 and the gas having a predetermined temperature introduced into the gas introduction path 212 in the nozzle 213 and directs the coating liquid 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 may be, for example, about several tens of cm.

For example, a gas having a predetermined temperature is always introduced from the warm air generator 22 into the gas introduction path 212, and the coating liquid is introduced from the liquid supply device 30 at a predetermined timing to spray the coating liquid from the nozzle 213 at an arbitrary timing. be able to. The spray pattern of the nozzle 213 is not particularly limited, and examples thereof include a flat pattern, a full cone pattern, a holo cone pattern, and a straight pattern.

(Example)
In this embodiment, parts means parts by mass.

[Pigment dispersion PD-1 (black)]
BET specific surface area is 150 m ² / g, average primary particle size is 20 nm, pH is 4.0, DBP oil absorption is 620 g / 100 g, 160 parts of carbon black NIPEX160 (manufactured by Degussa), polyoxyethylene (POE) (m = 40) 400 parts of -β-naphthyl ether (manufactured by Takemoto Oil & Fat Co., Ltd.) and 440 parts of ion-exchanged water were premixed to prepare a mixed slurry. Using a disc type media mill DMR type (manufactured by Ashizawa Finetech), using zirconia beads (filling rate 55%) with a diameter of 0.05 mm, a mixed slurry at a peripheral speed of 10 m / s and a liquid temperature of 10 ° C. for 3 minutes. Was circulated and dispersed. Next, the coarse particles were centrifuged with a centrifuge Model-7700 (manufactured by Kubota Shoji Co., Ltd.) to obtain a pigment dispersion PD-1 having a pigment concentration of 16% by mass.

[Pigment dispersion PD-2 (cyan)]
Pigment dispersion PD-2 with a pigment concentration of 16% by mass, similar to pigment dispersion PD-1, except that carbon black was changed to pigment blue 15: 3 chromofine blue (manufactured by Dainichiseika). Got

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

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

[Ink I-1]
25.00 parts of pigment dispersion PD-2, 40.00 parts of 3-ethyl-3-hydroxymethyloxetane, 2.00 parts of silicone-based surfactant TEGO Wet 270 (manufactured by Tomoe Kogyo Co., Ltd.) and 33.00. The ion-exchanged water of the portion was mixed, 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, the ink I-2 was obtained by filtering with a membrane filter having a pore size of 1.2 μm.

[Ink I-3]
50.00 parts of pigment dispersion PD-1, 30.00 parts of 3-ethyl-3-hydroxymethyloxetane, 2.00 parts of silicone-based surfactant TEGO Wet 270 (manufactured by Tomoe Kogyo Co., Ltd.) and 18.00 The ion-exchanged water of the portion was mixed, 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 the pigment dispersion PD-1 was changed to the pigment dispersion PD-3.

[Ink I-5]
25.00 parts of pigment dispersion PD-4, 25.00 parts of 3-ethyl-3-hydroxymethyloxetane, 20.00 parts of 1,3-butanediol, 2.00 parts of silicone-based surfactant TEGO Wet 270 (manufactured by Tomoe Kogyo Co., Ltd.) and 28.00 parts of ion-exchanged water were mixed, stirred for 1 hour, and then filtered through a membrane filter having a pore size of 1.2 μm to obtain ink I-5.

Table 1 shows the types and colors of the coloring materials used for the ink.

[Resin emulsion P-1 (silicon-modified acrylic resin)]
After sufficiently replacing the inside of the flask equipped with a mechanical stirrer, a thermometer, a nitrogen gas introduction tube, a reflux tube and a 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. After preparation, 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-methacryloxypropylmethyldimethoxysilane was dropped into a flask over 3 hours to polymerize the resin. Emulsion P-1 was obtained. At this time, the pH of the polymerization reaction solution was adjusted to 7 with an aqueous ammonia solution for polymerization. The average particle size of the resin emulsion P-1 measured using Microtrac UPA was 160 nm. The solid content concentration of the resin emulsion P-1 was 30% by mass.

[Coating liquid A-1]
A polyethylene (PE) wax emulsion AQUACER (registered trademark) 531 (manufactured by Big Chemie Japan) having a non-volatile content of 45% by mass was used as a coating liquid A-1. Here, the PE wax has a melting point of 130 ° C.

[Coating liquid A-2]
50.0 parts of modified polypropylene (PP) wax emulsion AQUACER® (registered trademark) 593 (manufactured by Big Chemie Japan) and 50.0 parts of resin emulsion P-1 with a non-volatile content of 30% by mass are mixed and stirred for 1 hour. Then, the coating liquid A-2 was obtained. Here, the modified PP wax has a melting point of 110 ° C.

[Coating liquid A-3]
The resin emulsion P-1 was used as a coating liquid A-3.

[Coating liquid A-4]
A silica spherical fine particle aqueous dispersion having a solid content of 20% by mass, Seahoster (registered trademark) KE-W30 (manufactured by Nippon Shokubai Co., Ltd.) was used as a coating liquid A-4.

[Coating liquid A-5]
High pure water containing no powder and coating liquid A-5 were used.

Table 2 shows the formulation of the coating solution.

(Example 1)
Ink I-1 was filled in an inkjet printer IPSiO GX5000 (manufactured by Ricoh) as an image forming apparatus in an environment of 23 ° C. and 50% RH. Next, by printing a chart on which the general symbols of JIS X 0208 (1997) and 2223 of 64 points and 128 points created by Microsoft Word2000 (manufactured by Microsoft) are described, the ink I- is printed on the recording medium by the liquid discharge head. 1 was applied.

At this time, the print mode is changed from the "glossy paper-standard clean" mode to "no color correction" or the "glossy paper-standard fast" mode in the driver attached to the printer. The mode was modified to "no color correction".

As a recording medium, Lumiart Gloss 90 gsm (manufactured by MONDI Color Copy Co., Ltd.) (hereinafter referred to as coated paper 1) or OK top coat + (manufactured by Oji Paper Co., Ltd.) having a basis weight of 73.3 g / cm ² (hereinafter referred to as coated paper 1) Coated paper 2) was used. Further, the general symbols of JIS X 0208 (1997) and 2223 are symbols having a square outer shape and the entire surface being filled.

Ten seconds after printing is completed, heated air and coating liquid A-1 are sent to the mini-atomization nozzle MMA-10 (manufactured by Everroy Trading Co., Ltd.), which is a two-fluid nozzle as a spray nozzle (sprayer), and vertically from the recording medium. The coating liquid A-1 was applied by spraying the printing surface of the recording medium from a position 30 cm away in the direction. At this time, the scanning speed of the spray nozzle (relative speed between the recording medium and the spray nozzle) was adjusted so that the coating amount of the coating liquid A-1 was 100 mg per A4 size.

The heated air is generated by the warm air generator HAP4020 (manufactured by Hachiko Denki Co., Ltd.), and the temperature immediately before being mixed with the coating liquid by the spray nozzle is a K-type thermocouple with a tip welding type and a wire diameter of 0.2 mm. Measured in pairs (manufactured by Three High). At this time, the set temperature of the warm air generator was adjusted so that the temperature of the air was 140 ° C. The amount of the coating liquid sent to the spray nozzle was adjusted to 10 mL / min.

Further, 30 seconds after the application of the coating liquid 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 Co., Ltd.) having a wire diameter of 0.2 mm into contact with the recording medium in the tip welding type.

(Example 2)
An image was formed in the same manner as in Example 1 except that ink I-3 was used instead of ink I-1 and coating liquid A-2 was used instead of coating liquid A-1.

(Examples 3 and 4)
An image was formed in the same manner as in Example 1 except that Ink I-4 was used in Example 3 and Ink I-5 was used in Example 4 instead of Ink I-1.

(Example 5)
An image was formed in the same manner as in Example 1 except that ink I-2 was used instead of ink I-1.

(Example 6)
An image was formed in the same manner as in Example 1 except that the recording medium was not heated after the coating liquid A-1 was applied.

(Example 7)
An image was formed in the same manner as in Example 1 except that the gas sent to the spray nozzle when the coating liquid A-1 was applied was changed from air to nitrogen.

(Example 8)
An image was formed in the same manner as in Example 1 except that the heating set temperature of the warm air generator was lowered and the temperature of the air introduced into the spray nozzle was adjusted to 50 ° C.

(Example 9)
An image was formed in the same manner as in Example 1 except that the set heating temperature of the warm air generator was lowered and the temperature of the air introduced into the spray nozzle was adjusted to 60 ° C.

(Example 10)
An image was formed in the same manner as in Example 1 except that the heating set temperature of the warm air generator was raised and the temperature of the air introduced into the spray nozzle was adjusted to 200 ° C.

(Example 11)
An image was formed in the same manner as in Example 1 except that the heating set temperature of the warm air generator was raised and the temperature of the air introduced into the spray nozzle was adjusted to 220 ° C.

(Examples 12 and 13)
An image was formed in the same manner as in Example 1 except that the coating liquid A-3 was used in Example 12 and A-4 was used in Example 13 instead of the coating liquid A-1.

(Example 14)
An image was formed in the same manner as in Example 1 except that the heating set temperature of the warm air generator was raised and the temperature of the air introduced into the spray nozzle was adjusted to 350 ° C.

(Comparative Example 1)
An image was formed in the same manner as in Example 1 except that the set heating temperature of the warm air generator was lowered and the temperature of the air introduced into the spray nozzle was adjusted to 40 ° C.

(Comparative Example 2)
An image was formed in the same manner as in Example 1 except that the coating liquid A-5 was used instead of the coating liquid A-1.

(Comparative Example 3)
An image was formed in the same manner as in Example 1 except that the coating liquid A-5 was used instead of the coating liquid A-1.

(Comparative Example 4)
An image was formed in the same manner as in Example 1 except that the heating set temperature of the warm air generator was raised and the temperature of the air introduced into the spray nozzle was adjusted to 400 ° C.

Table 3 shows the image formation conditions of Examples and Comparative Examples.

(Evaluation)
Next, the image density, image glossiness, fixability, blocking resistance and paper expansion / contraction were evaluated. In all the evaluations, AA, A, and B were passed, and C was rejected.

<Image density>
Using X-Rite 938 (manufactured by X-Rite Co., Ltd.), the image density of the area on which the general symbol of 64 points of 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 user setting of the glossy paper in the driver attached to the printer, and the coated paper 1 is used as the recording medium. Using.

The image density was judged 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 Kogyo Co., Ltd.), the 60 ° glossiness of the area on which the 128-point general symbol of 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 user setting of the glossy paper in the driver attached to the printer, and the coated paper 1 is used as the recording medium. Using.

The image glossiness was judged 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 128-point JIS X 0208 (1997), 2223 general symbols of the recording medium are printed is the same as the recording medium used for printing, and is rubbed 10 times with an unprinted recording medium and is not printed. The transferability of the pigment to 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 user setting of the glossy paper in the driver attached to the printer, and the coated paper 1 is used as the recording medium. Using.

Fixability was judged by the following evaluation criteria.

〔Evaluation criteria〕
A: Almost no pigment transfer to the recording medium B: Slight transfer of pigment to the recording medium (less than 10% of the total area)
C: Transfer of pigment to recording medium is clearly seen (area of 10% or more of the whole)
<Fixability 2>
The fixability 2 was evaluated in the same manner as the fixability 1 except that the coated paper 2 was used as the recording medium.

<Fixability 3>
The print mode is the same as that for fixability 1, except that the "glossy paper-standard fast" mode is changed to "no color correction" from the user setting of glossy paper in the driver attached to the printer. Fixability 3 was evaluated.

<Blocking resistance 1>
A recording medium in which the 128-point JIS X 0208 (1997), 2223 general symbols of the recording medium are printed is the same as the recording medium used for printing 3 minutes after the image is formed, and is not printed. (4 cm x 4 cm) was stacked, and a rubber sheet having a length of 2 cm, a width of 2 cm, and a thickness of 0.2 cm was placed in the center of the recording medium. Next, a weight was placed on the rubber sheet so that the pressure applied from the rubber sheet to the recording medium was 0.5 kgf / cm ^2, and the mixture was left to stand in an environment of 23 ° C. and 50% RH for 12 hours. Further, the stacked recording media were peeled off, and the transfer condition of the pigment to the non-printed recording medium 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 user setting of the glossy paper in the driver attached to the printer, and the coated paper 1 is used as the recording medium. Using.

The blocking resistance was judged by the following evaluation criteria.

〔Evaluation criteria〕
A: There is almost no transfer of pigment to the recording medium.

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

<Paper expansion and contraction>
After measuring the length of the short side of the A4 size recording medium, the general symbol of JIS X 0208 (1997), 2223 of 512 points was printed in the center of the recording medium to form an image. After printing, the length of the short side of the recording medium was measured again to evaluate the expansion and contraction of the paper. 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 user setting of the glossy paper in the driver attached to the printer, and the coated paper 1 is used as the recording medium. Using.

Paper expansion and contraction was judged by the following evaluation criteria.

〔Evaluation criteria〕
A: The amount of change in the length of the short side of the recording medium is −0.10 mm or more and 0.10 mm or less.

B: The amount of change in the length of the short side of the recording medium is less than -0.10 mm-0.50 mm or more, or more than 0.10 mm and 0.50 mm or less.

C: The amount of change in the length of the short side of the recording medium is less than −0.50 mm or more than 0.50 mm.

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

From Table 4, Examples 1 to 14 are AA, A, or B in any of the evaluations, form an image excellent in image density, image glossiness, fixability, and blocking resistance on the coated paper, and stretch the paper. It can be seen that can be suppressed.

On the other hand, in Comparative Example 1, since the temperature of the air supplied to the spray nozzle is low, the fixing property and blocking resistance of the image formed on the coated paper are inferior. Further, in Comparative Example 2, since the coating liquid does not contain powder or wax, the fixing property and blocking resistance of the image formed on the coated paper are inferior. In Comparative Example 3, since the coating liquid A-1 is not applied, the image density, image glossiness, fixability, and blocking resistance of the image formed on the coated paper are inferior, and the paper expansion and contraction is large. Further, in Comparative Example 4, each evaluation could not be performed because the temperature of the air introduced into the spray nozzle was too high and the coated paper was damaged (indicated as "-" in Table 4).

Although the preferred embodiments and the like have been described in detail above, the embodiments are not limited to the above-described embodiments and the like, and various embodiments and the like described above are used without departing from the scope of the claims. Modifications and substitutions can be added.

1 Image forming device 10 Liquid discharge head 20 Sprayer 21 Sprayer 22 Warm air generator 23 Temperature detection means 211 Liquid introduction path 212 Gas introduction path 213 Nozzle

Japanese Unexamined Patent Publication No. 2012-21396

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

An object of the present invention is to provide an image forming apparatus having excellent fixing property and blocking resistance.

In this image forming apparatus, a liquid discharge head that applies a first liquid used for image formation to a discharge target object and a surface of the discharge target object on the side to which the first liquid is applied are provided with non-volatile components. It has a spraying device for spraying a second liquid containing the above with a gas having a temperature of 50 ° C. or higher and 350 ° C. or lower.

Claims (10)

The process of applying the first liquid used for image formation to the discharge target by the liquid discharge head, and
Image formation including a step of spraying a second liquid containing a non-volatile component together with a gas of 50 ° C. or higher and 350 ° C. or lower by a spraying device on the surface of the discharge target on the side coated with the first liquid. Method. The image forming method according to claim 1, wherein the non-volatile component is a powder or wax. The image forming method according to claim 2, wherein the powder is a resin. The image forming method according to claim 2, wherein the wax is a water-dispersible wax. The image forming method according to any one of claims 1 to 4, wherein the temperature of the gas is 60 ° C. or higher and 200 ° C. or lower. The image forming method according to any one of claims 1 to 5, wherein the gas is air. The image forming method according to any one of claims 1 to 6, further comprising a step of heating the discharge object after the step of spraying with the spraying device. A sprayer including a liquid introduction path, a gas introduction path, and a nozzle for spraying a second liquid containing a non-volatile component introduced into the liquid introduction path together with the gas introduced into the gas introduction path.
A spraying device including a warm air generator that introduces a gas having a temperature of 50 ° C. or higher and 350 ° C. or lower into the gas introduction path. The spraying device according to claim 8, further comprising a temperature detecting means for detecting the temperature of the gas introduced into the gas introduction path and outputting the detection result to the warm air generator. A liquid discharge head that applies the first liquid used for image formation to the discharge target,
The eighth or ninth aspect of the present invention, wherein a second liquid containing a non-volatile component is sprayed on a surface of the discharge object on the side coated with the first liquid by a spraying device together with a gas having a temperature of 50 ° C. or higher and 350 ° C. or lower. A spraying device and an image forming device having.