Image recording apparatus

Abstract

To provide an image recording apparatus that enables favorable image formation regardless of the type of a recording target medium.SOLUTION: An image recording apparatus includes: recording target medium chemical surface treatment means having a chlorine dioxide supply section that supplies chlorine dioxide to a recording target medium and a light irradiation section that irradiates the recording target medium with light; and image-forming material applying means for applying an image-forming material to the recording target medium chemically surface-treated by the recording target medium chemical surface treatment means.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an image recording apparatus.

Background Art

[0002] An image recording apparatus may have a recording medium surface treatment means for physically or chemically treating and modifying the surface of a recording medium in order to make the recording medium suitable for image recording in addition to an image recording means. The image forming material applying means and the recording medium processing means may be performed by separate apparatuses, or may be continuously executed by one apparatus.

[0003] For example, Patent Document 1 describes an inkjet recording apparatus having a conveying means for conveying a recording medium, an undercoat liquid applying means for applying an undercoat liquid that cures when irradiated with active energy rays to one surface of the recording medium, an undercoat liquid semi-curing means for irradiating the recording medium to which the undercoat liquid has been applied with active energy rays to semi-cure the undercoat liquid applied on the recording medium, and an image forming means including an inkjet head that discharges ink containing a coloring material to form an image on the recording medium to which the undercoat liquid has been applied.

[0004] However, the surface treatment of the recording medium needs to consider the matching with the image forming material, including physical properties, not only for the recording medium itself. For example, since the image forming material used in the inkjet method has a low viscosity, problems caused by the fluidity of the ink are likely to occur while the ink is being applied to and fixed on the recording medium. When the recording medium to be used is a low-absorbency recording medium, color bleeding due to color mixing between ink droplets, occurrence of spots due to beading phenomena caused by droplet fusion, etc. may occur. When the affinity with the ink is low, the spread of the ink dot diameter is not good, so an excessive amount of ink droplets is likely to be required. On the other hand, when the recording medium to be used is a high-absorbency recording medium, the spread of the ink droplets becomes irregular due to the non-uniformity of the recording medium, and excessive penetration or beard-like bleeding due to capillary force along the fiber composition is likely to occur.

[0005] In addition, as a surface treatment technology for the recording medium, for example, a coating layer with high affinity for ink is provided to achieve a surface property suitable for the ink, a compound that reacts with the ink is applied, plasma treatment for improving the affinity with the ink is performed, and the like.

[0006] However, when a coating layer with high affinity for ink is provided, the texture and glossiness of the recording medium are changed, so that the characteristics of the recording medium are greatly changed, the versatility as a recording method-specific recording medium is lost, and the coating cost also tends to increase. In addition, when a compound that reacts with the ink is applied, it affects the chemical properties and hardness of the recording medium, and a toxic chemical substance may remain on the recording medium, or the re-dissolution of the coating may affect different recording method printing. Thus, the method of applying a compound that reacts with the ink may affect the safety, versatility, and printing process of the recording medium. In addition, when plasma treatment for improving the affinity with the ink is performed, the surface of the recording medium can be physically modified, but the modification remains only on the outermost surface, and the amount of modification depends on the amount of energy applied. Therefore, in a general environment, there is a limit to the amount of modification, and the recording media and target inks showing effects are limited.

[0007] For the reasons as described above, since it is necessary to perform surface treatment of the recording medium in consideration of matching with the image forming material as well as the recording medium, it is difficult to make an image recording apparatus including an image forming material applying means and a recording medium surface treatment means show good image recording suitability regardless of the type of the recording medium. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] An object of the present invention is to provide an image recording apparatus capable of forming a good image regardless of the type of the recording medium. MEANS FOR SOLVING THE PROBLEMS

[0009] In order to solve the above problems, an embodiment of the present invention provides a recording medium chemical surface treatment means having a chlorine dioxide supply unit for supplying chlorine dioxide to the recording medium and a light irradiation unit for irradiating light, and an image forming material applying means for applying an image forming material to the recording medium chemically surface-treated by the recording medium chemical surface treatment means. An image recording apparatus including the above is provided.

Effect of the Invention

[0010] According to an embodiment of the present invention, an image recording apparatus capable of forming good images can be provided regardless of the type of the recording medium.

Brief Description of the Drawings

[0011]

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Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described in detail. The embodiments described below are preferred embodiments of the present invention, but the scope of the present invention is not unduly limited by the following description.

[0013] (Image Recording Apparatus) The image recording apparatus of the present invention has a chemically treating means for a recording medium having a chlorine dioxide supply unit for supplying chlorine dioxide to the recording medium and a light irradiation unit for irradiating light, and an image forming material applying means for applying an image forming material to the recording medium chemically surface-treated by the chemically treating means for a recording medium. It is an image recording apparatus provided with these. According to the present invention, it is possible to provide an image recording apparatus capable of forming good images regardless of the type of the recording medium. In addition, the image recording apparatus of the present invention can include other means.

[0014] <Recording medium chemical surface treatment means> The recording medium chemical surface treatment means includes a chlorine dioxide supply unit that supplies chlorine dioxide and a light irradiation unit that irradiates light. The recording medium chemical surface treatment means preferably has a shielding mechanism that blocks outside air so that the recording medium can be chemically surface-treated in a sealed space filled with a high concentration of chlorine dioxide. The recording medium chemical surface treatment means preferably has an exhaust mechanism for discharging the supplied chlorine dioxide. By discharging the supplied chlorine dioxide, unreacted chlorine dioxide can be supplied to the recording medium except for the reacted gas, and the chemical surface treatment of the recording medium surface can be continuously performed.

[0015] <<Chemical surface treatment>> In this specification, "chemical surface treatment" refers to a treatment that increases the hydrophilic functional groups on the surface of the recording medium by causing a chemical reaction that oxidizes the surface of the recording medium by irradiating light on the chlorine dioxide supplied to the surface of the recording medium, and modifies the recording medium to have increased hydrophilicity on its surface.

[0016] Chlorine dioxide has radicals in its molecule, and it is considered that chlorine dioxide decomposes to generate chlorine radicals and oxygen molecules by absorbing light energy hν (h is Planck's constant, ν is the frequency of light).

[0017] The radicals of chlorine dioxide itself and the chlorine radicals generated by photolysis attack the surface of the recording medium and cause a chemical reaction of oxidation. When the recording medium is an organic substance, these radicals attack the hydrocarbon groups on the surface of the organic substance and cause an oxidation reaction. Even in the state where no light is applied, chlorine dioxide has reactivity due to its radical nature, but it is very weak for modifying the recording medium. Therefore, the modification is promoted by irradiating light to generate chlorine radicals.

[0018] For example, when the recording medium is an organic substance, the chemically surface-treated recording medium has a state where the surface of the recording medium is oxidized and the number of carboxyl groups increases compared to before the treatment. Therefore, the surface characteristics of the recording medium become hydrophilic and the surface pH decreases. By controlling these characteristics, the wet spreading or adhesion of the imaging material to the surface of the recording medium can be controlled.

[0019] The temperature when chemically surface-treating the recording medium is not particularly limited, but is preferably -20°C or higher and 100°C or lower, and more preferably 0°C or higher and 60°C or lower. The atmospheric pressure during the reaction is not particularly limited. For example, the reaction can be carried out at 0.1 MPa or higher and 100 MPa or lower. Therefore, it is also possible to chemically surface-treat the recording medium at 5 to 35°C under atmospheric pressure without performing heating, pressurization, depressurization, etc. Since the present invention enables chemical surface treatment of the recording medium at 5 to 35°C under atmospheric pressure, even if the recording medium contains a polymer with low heat resistance, imaging can be performed without affecting the characteristics of the recording medium.

[0020] <<Shielding mechanism for blocking outside air>> Examples of the shielding mechanism for blocking the outside air include members for the reaction chamber, nip members, rollers, irradiation windows, etc.

[0021] Since the member for the reaction chamber is a member in contact with chlorine dioxide gas, it preferably contains a metal that is resistant to rust. As the metal resistant to rust, stainless steel is preferable, austenitic stainless steel resistant to corrosion is more preferable, and SUS304L, SUS316, SUS312L, SUS321, SUS347 are particularly preferable.

[0022] In addition, since it comes into contact with a high-concentration chlorine dioxide gas, corrosion can also be suppressed by providing a protective film on the surface of the portion in contact with the chlorine dioxide gas. The protective film is preferably a non-metallic film, and a coating made of glass lining or ceramic is more preferable because of its excellent durability, acid resistance, and heat resistance. As the protective film, a resin coating can also be used. A coating of a fluororesin is preferable. For example, coatings by surface treatment by powder compression heating of polytetrafluoroethylene, coatings by a treatment of forming a film by electroless plating of fluororesin particles to form a protective film, etc. can be mentioned.

[0023] Since the nip member can fill the gap between the chamber and the processing table by deforming and adhering, and can suppress the outflow of gas to the outside of the reaction chamber, it is preferable to use an elastic member such as deformable rubber. Further, the rubber is preferably one that hardly reacts with a gas containing chlorine dioxide. For example, it is preferable to use a fluorine-based rubber, a silicone rubber, etc.

[0024] Since the roller can fill the gap between the chamber and the processing table by deforming and adhering, and can suppress the outflow of gas to the outside of the reaction chamber, it is preferable to use an elastic member such as deformable rubber. Further, the rubber is preferably one that hardly reacts with a gas containing chlorine dioxide. For example, it is preferable to use a fluorine-based rubber, a silicone rubber, etc. In addition, a non-metallic film, a resin coating, etc. may be used for the roller in order to reduce the influence of corrosion by chlorine dioxide.

[0025] The irradiation window is preferably transparent with little light absorption. Further, it is preferably made of a chemically stable material that does not contain polyvalent metals as impurities. For example, quartz glass, borosilicate glass, etc. are preferably mentioned.

[0026] <<Exhaust mechanism>> Examples of the exhaust mechanism include an exhaust pipe, an exhaust valve, an exhaust pump, an exhaust gas control valve, etc. As long as it does not go against the object of the present invention, anything that can be used for exhaust can be used. The exhaust mechanism preferably has a chlorine dioxide-derived compound adsorption mechanism that adsorbs a chlorine dioxide-derived compound as described above in order to adsorb and remove toxic gas components such as acidic gases such as unreacted chlorine dioxide gas and chlorine gas of reaction residues in the exhaust.

[0027] Among the exhaust mechanisms, the member in contact with chlorine dioxide gas preferably contains a rust-resistant metal. As the rust-resistant metal, stainless steel is preferable, austenitic stainless steel that is resistant to corrosion is more preferable, and SUS304L, SUS316, SUS312L, SUS321, SUS347 are particularly preferable.

[0028] In addition, since it comes into contact with a high-concentration chlorine dioxide gas, it is also possible to suppress corrosion by providing a protective film on the surface of the member in contact with the chlorine dioxide gas. The protective film is preferably a non-metal coating, and a coating with glass lining or ceramic is more preferable because of its excellent durability, acid resistance, and heat resistance. As the protective film, a resin coating can also be used, and a fluororesin coating is preferable. For example, coatings by surface treatment by powder compression heating of polytetrafluoroethylene, coatings by a process of forming a film by depositing fluororesin particles by electroless plating to form a protective film, etc. can be mentioned.

[0029] Also, in places where heat is not applied, it is possible to use a resin material. Exhaust pipes, exhaust gas adsorption filter housings, etc. that come into contact with a high-concentration chlorine dioxide gas and require a material with strong oxidation resistance are preferably those containing vinyl chloride from the viewpoints of cost and flexibility. The chemical surface treatment of the recording medium according to the embodiment of the present invention can be performed as follows using chlorine dioxide and light.

[0030] <<<Chlorine Dioxide-derived Compound Adsorption Mechanism>>> The exhaust mechanism preferably has a mechanism for recovering and treating compounds derived from chlorine dioxide that are discharged or leaked. For example, it is preferably adsorbed by a chlorine dioxide-derived compound adsorption mechanism that adsorbs compounds derived from chlorine dioxide. The chlorine dioxide-derived compound adsorption mechanism is not particularly limited as long as it does not conflict with the object of the present invention. Examples include an exhaust gas adsorption filter, a wet scrubber, etc. Specifically, columns filled with activated carbon, hydrotalcite, etc., absorption and neutralization removal with water or alkaline water for adsorption, etc. can be mentioned. Also, for the exhausted or leaked gas, an acidic component in the gas may be adsorbed and removed by spraying a 1% by mass aqueous solution of DMSO to separate and recover the aerosol.

[0031] <<Chlorine Dioxide Supply Unit>> The chlorine dioxide supply unit includes a chlorine dioxide gas source. The chlorine dioxide supply unit supplies chlorine dioxide to the surface of the recording medium, and the supplied chlorine dioxide may be a gas or a liquid such as a solution. The substance supplied by the chlorine dioxide supply unit may be a gas or a liquid containing chlorine dioxide. The supplied chlorine dioxide, or the gas or liquid containing chlorine dioxide, contacts the surface of the recording medium. The method of supplying chlorine dioxide is not particularly limited. For example, a substance capable of generating chlorine dioxide such as chlorous acid or its salt is dissolved in water and allowed to stand, or hydrochloric acid is further added thereto and allowed to stand, and chlorine dioxide radicals are spontaneously generated from chlorite ions for supply. Chlorine dioxide may be supplied using a gas cylinder or a generator, and is not limited to the above method.

[0032] The gas containing chlorine dioxide supplied to the recording medium can be subjected to chemical surface treatment by mixing with the air in the atmosphere without being replaced with an inert gas or the like. As long as the gas does not react with chlorine dioxide and cause an explosion during the process of chemically surface-treating the recording medium, it is possible to mix any substance with chlorine dioxide to perform chemical surface treatment. Therefore, in the present invention, the step of chemically surface-treating the recording medium by the recording medium chemical surface treatment means can be performed in the atmosphere, and all other steps including the step of applying the image forming material to the recording medium can also be performed in the atmosphere.

[0033] As the chlorine dioxide supply unit, in addition to a chlorine dioxide gas source, for example, a chlorine dioxide gas valve, a chlorine dioxide gas pipe, an air pipe, an air valve, a pressure gauge, a chlorine dioxide concentration adjustment chamber, a chlorine dioxide concentration meter, a supply gas adjustment valve, and other components that can be used for the supply of chlorine dioxide may be included.

[0034] Among the chlorine dioxide supply unit, the member in contact with the chlorine dioxide gas is preferably resistant to rust, and the content is the same as that described above for the exhaust mechanism.

[0035] Since it is preferable to remove the chlorine dioxide-derived compound leaking from the chlorine dioxide supply unit, it is preferable to have the chlorine dioxide-derived compound adsorption mechanism.

[0036] -Chlorine dioxide gas source- As the chlorine dioxide gas source, for example, either a gas cylinder or a gas generator may be used, and the generation method is not particularly limited. The gas generator may be manufactured according to the generation mechanism of chlorine dioxide gas. The method for generating chlorine dioxide gas is not limited. For example, an apparatus that generates chlorine dioxide gas by reacting commercially available 25% sodium chlorite with 9% hydrochloric acid, an apparatus that supplies chlorine dioxide gas generated by adding sodium chlorite powder as disclosed in Japanese Patent No. 5449691 to an acidic solution, an apparatus that supplies chlorine dioxide gas generated by adding pelletized sodium chlorite as disclosed in Japanese Patent No. 5944760 to an acidic solution, an apparatus that supplies the generated chlorine dioxide using the method of generating chlorine dioxide from an aqueous solution of hydrochloric acid-acidic sodium chlorite as disclosed in Japanese Patent No. 7117793, etc. can be used.

[0037] Specifically, for example, 10 parts by mass of sodium chlorite (manufactured by Kanto Chemical Co., Inc.) and 500 parts by mass of high-purity water are placed in a glass container, and after dissolving sodium chlorite in high-purity water, 5.3 parts by mass of an aqueous hydrochloric acid solution (manufactured by Kishida Chemical Co., Ltd.) with a concentration of 35 to 37% by mass is added. The prepared mixture is allowed to stand for 24 hours, and the UV spectrum of the mixture after 24 hours is measured with a spectrophotometer to confirm that absorption derived from chlorine dioxide is observed in the vicinity of 350 to 360 nm. The chlorine dioxide generated from the mixture can be used.

[0038] There is no limitation on the concentration of the supplied chlorine dioxide gas, but depending on the treatment content, it is preferable to supply a chlorine dioxide concentration higher than the control upper limit concentration of the gas concentration.

[0039] Chlorine dioxide gas can be used by mixing it with an inert gas such as nitrogen gas or argon gas, or a gas containing active species such as air or oxygen gas in addition to chlorine dioxide. In particular, air and oxygen gas serve as a source of oxygen for oxidizing the surface when performing chemical surface treatment. Also, when mixing air, it is preferable because the apparatus can be simplified since an air supply source does not need to be installed.

[0040] A chlorine dioxide concentration adjustment chamber may be provided between the chlorine dioxide gas source and the reaction chamber for chemical surface treatment, and it can be adjusted to an appropriate concentration in order to add other gases according to the chlorine dioxide gas concentration and supply them to the reaction system. The gas used for adjustment is not limited to air, oxygen, etc., and a gas containing a component that can adjust the reaction by being mixed with chlorine dioxide gas may also be used. Also, for use in a chemical reaction, it is preferable to adjust the concentration or pressure of the supplied gas, and further, it is preferable to adjust the temperature, humidity, or the concentration of other gas components.

[0041] <<Light irradiation unit>> The light irradiation unit includes a light source, and light is irradiated from the light irradiation unit onto the chlorine dioxide supplied to the surface of the recording medium. At this time, the peak wavelength of the irradiated light is preferably 200 nm or more and 800 nm or less, and more preferably 270 nm or more and 470 nm or less. From the viewpoint of activating photolysis, 300 nm or more and 400 nm, which is near the maximum absorption wavelength of chlorine dioxide radical at 360 nm, is even more preferable.

[0042] As the light, natural light such as sunlight, ultraviolet light, etc. can be used. The light source of the irradiated light is not particularly limited, but when using ultraviolet light, light sources such as xenon lamps, halogen lamps, fluorescent lamps, mercury lamps, high-pressure mercury lamps, metal halide lamps, LEDs, etc. may be appropriately used.

[0043] In addition to the above, the light irradiation unit can include anything that can be used for light irradiation, for example, pipes for cooling the light source, a cooling circulator for water cooling, a light diffusing plate, a light guiding plate, etc.

[0044] Since the light source tends to have heat, it is preferable to cool the light source by water cooling or the like. When performing water cooling, the light source and the water cooling circulator may be connected to the pipes for cooling the light source, and cooled by circulating cooling water. By cooling in this way, the heat of the light source can be efficiently removed.

[0045] Also, when using an LED, by using a water-cooled LED with high cooling efficiency, it is possible to prevent heat generation when LED light-emitting elements are integrated, thus preventing a decrease in the element lifespan and facilitating an increase in the integration density.

[0046] Also, in order to suppress the reaction activity in chemical surface treatment and avoid unnecessary overheating of the recording medium, a filter or the like may be used for the light source to cut wavelengths other than the necessary wavelength. When the infrared rays exceeding 800 nm contained in the irradiation light increase, the temperature of the recording medium and the reaction system rises according to the irradiation conditions of the light source. Therefore, from the viewpoint of stably controlling the reaction and suppressing deformation of the recording medium, it is preferable to cut the long-wavelength component of the light.

[0047] From the viewpoints of good energy efficiency, little heat generation, little influence on the temperature inside the reaction chamber, limited emission wavelength, and low power consumption, the light source for the irradiation light is preferably a UV-LED light source which is an ultraviolet LED light source. If it is a UV-LED light source, even as a UV-LED array light source with a plurality of UV-LEDs arranged, since the heat generation from the light source is small, the device can be made small, and the image recording device of the present invention can be configured to be power-saving.

[0048] Commercially available UV-LED arrays are available from Phoseon Technology, Heraeus Co., Ltd., Ushio Electric Inc., Hamamatsu Photonics K.K., etc., and UV-LED array light sources with peak wavelengths of 365 nm, 385 nm, 395 nm, and 405 nm can be obtained.

[0049] A light diffusing plate may be provided between the light source and the recording medium. When the recording medium does not move during light irradiation, since the irradiation position is fixed, the non-uniformity of the light source is likely to appear as the non-uniformity of the chemical surface treatment. However, by irradiating the recording medium with light through the light diffusing plate, the rectilinearity of the light can be relaxed, and it becomes possible to perform uniform irradiation on the recording medium. When using an LED light source, since the light has high directivity from the light-emitting element, it is preferable to provide a light diffusing plate between the LED light source and the recording medium.

[0050] Also, in order to control the irradiation direction of light with a light guiding plate, a light guiding plate may be provided near the light source.

[0051] Although the irradiation time of light is not limited, since the purpose is for the surface modification of the recording medium to be in a state suitable for image formation, the required time varies depending on the recording medium or the image forming material. Also, the amount of chlorine radicals generated may vary depending on the amount of chlorine dioxide, the wavelength and light amount of the irradiation light, etc. Since the conditions for surface modification of the recording medium can change according to the radical amount, the light irradiation time may be arbitrarily controlled. From the viewpoint of increasing the image forming speed, it is preferably irradiated for 1 second or more and 600 seconds or less, and more preferably irradiated for 1 second or more and 60 seconds or less.

[0052] <<Other members>> The recording medium chemical surface treatment means may have other members, and examples include various sensors, bearings, etc.

[0053] Examples of the sensor include a temperature sensor, a pressure sensor, a humidity sensor, a chlorine dioxide sensor, an oxygen sensor, an air flow meter, an anemometer, etc.

[0054] Examples of the material included in the bearing include stainless steel, ceramics, fluororesin, etc. On the surface of the bearing, in order to reduce the influence of corrosion by chlorine dioxide, similar to the protective film provided on the metal surface described above, a non-metallic film, a resin coating, etc. can be used.

[0055] <Recording medium> The recording medium is not particularly limited as long as it does not conflict with the object of the present invention, but it is preferable that the surface to which the image forming material is applied has poor liquid absorbency. As used herein, "poor liquid absorbency" means that the amount of pure water transferred to the recording medium at a contact time of 40 ms measured by a dynamic scanning liquid absorption meter is 9 ml / m 2 or less, and the amount of pure water transferred to the recording medium at a contact time of 400 ms is 29 ml / m 2 or less. When the surface of the recording medium to which the image forming material is applied has poor liquid absorbency, even when using a liquid image forming material such as a solvent-based ink, an ultraviolet curable ink, or an aqueous ink, excessive penetration, bleeding, or irregular spreading of ink droplets is less likely to occur, and good image formation is easily achieved.

[0056] Examples of the recording medium that can be used include ordinary paper, high-quality paper, recycled paper, thin paper, thick paper, coated paper, synthetic resin films such as polypropylene film, polyethylene terephthalate film, and polyvinyl chloride film, metal thin films, fabrics, and other materials on which an image can be formed with ink or the like on the surface. In particular, based on the absorption characteristics measured by a dynamic scanning liquid absorption meter, plastic films such as polyvinyl chloride film, polyethylene terephthalate film, polypropylene film, polyethylene film, polycarbonate film, polyimide film, polystyrene film, and nylon film, and existing recording media for printing such as laminated paper, coated paper, and tarpaulin having a surface made of a non-porous material can be preferably used.

[0057] Examples of the poorly liquid-absorbent recording medium having a surface to which an image forming material is applied include synthetic resin films such as polypropylene film (hereinafter referred to as PP film), polyethylene terephthalate film (hereinafter referred to as PET film), and polyvinyl chloride film, coated paper, metal thin films, and tarpaulins such as cloth coated with resin. In particular, from the absorption characteristics by a dynamic scanning liquid absorber, plastic films such as polyvinyl chloride film, polyethylene terephthalate film (PET film), polypropylene film (PP film), polyethylene film, polycarbonate film, polyimide film, polystyrene film, and nylon film, and existing printing recording media such as laminated paper, coated paper, and tarpaulin having a surface made of a non-porous material can be preferably used.

[0058] Examples of commercially available products of the polyvinyl chloride film include IJ180 manufactured by 3M Japan Co., Ltd., and GIY-11Z5 gloss manufactured by Lintec Sign Systems Co., Ltd.

[0059] Examples of commercially available products of the polypropylene film (PP film) include Pyren film P1011, P-2002, P-2161, P-4166 manufactured by Toyobo Co., Ltd., PA-20, PA-30, PA-20W manufactured by SUNTOX Co., Ltd., and FOA, FOS, FOR manufactured by Futamura Chemical Co., Ltd.

[0060] Examples of the polyethylene terephthalate film (PET film) include E-5100, E-5102 manufactured by Toyobo Co., Ltd., Lumirror #50-T60, P60, P375 manufactured by Toray Industries, Inc., and G2, G2P2, K, SL manufactured by Teijin DuPont Films Co., Ltd.

[0061] Examples of the nylon film include Harden film N-1100, N-1102, N-1200 manufactured by Toyobo Co., Ltd., and ON, NX, MS, NK manufactured by Unitika Ltd.

[0062] In addition, examples of the coated paper include OK Top Coat + (Plus), OK Top Coat Gloss +, OK Top Coat S, OK Casablanca, OK Casablanca V, OK Trinity, OK Trinity NaVi, New Age, New Age W, OK Top Coat Matt N, OK Royal Coat, OK Top Coat Dal, Z Coat, OK Matsuhime, OK Matsuou, OK Matsuou Satin, OK Top Coat +, OK Non - wrinkle, OK Coat V, OK Coat N Green 100, OK Matt Coat Green 100, New Age Green 100, Z Coat Green 100, manufactured by Oji Paper Co., Ltd., Aurora Coat, Shiraoi Matt, Imperial Matt, Silver Dia, Recycled Coat 100, Cycle Matt 100, manufactured by Kitakami Paper Co., Ltd., Myu Coat, Myu White, Myu Matt, White Myu Matt, manufactured by Chukoku Pulp Industry Co., Ltd., Thunderbird Coat N, Regina Thunderbird Coat 100, Thunderbird Matt Coat N, Regina Thunderbird Matt 100, manufactured by Mitsubishi Paper Mills Limited, Pearl Coat, White Pearl Coat N, New V Matt, White New V Matt, Pearl Coat REW, White Pearl Coat NREW, New V Matt REW, White New V Matt REW, manufactured by Oji Paper Co., Ltd., OK Coat L, Royal Coat L, OK Coat LR, OK White L, OK Royal Coat LR, OK Coat L Green 100, OK Matt Coat L Green 100, manufactured by Oji Paper Co., Ltd., Easter DX, Recycled Coat L100, Aurora L, Recycled Matt L100 <sss>Energy White, made by Oji Paper Co., Ltd., Utrocoat L, Matisse Coat, made by Hokuetsu Paper Mills, Ltd., High Alpha, Alpha Mat, (N) Kinmari L, Kinmari HiL, made by Mitsubishi Paper Mills Limited, N Pearl Coat L, N Pearl Coat LREW, Swing Mat REW, made by Chukoku Pulp & Paper Co., Ltd., Super Eminence, Eminence, Chaton, made by Oji Paper Co., Ltd., OK Medium Coat, (F) MCOP, OK Astro Gloss, OK Astro Dal, OK Astro Mat, King O made by Nippon Paper Industries Co., Ltd., OK Royal Light S Green 100, OK Everlight Coat, OK Everlight R, OK Evergreen, Clean Hit MG, OK Fine Coating Super Eco G, Eco Green Dal, OK Fine Coating Mat Eco G100, OK Starlight Coat, OK Soft Royal, OK Bright, Clean Hit G, Yamayuri Bright, Yamayuri Bright G, OK Aqua Light Coat, OK Royal Light S Green 100, OK Bright (Rough Finish), Snow Mat, Snow Mat DX, OK Sogi Hime, OK Sogi Yuri, made by Nippon Paper Industries Co., Ltd., Pyrenees DX, Pegasus Hyper 8, Aurora S, Andes DX, Super Andes DX, Space DX, Seine DX, Special Gravure DX, Pegasus, Silver Pegasus, Pegasus Harmony, Greenland DX100, Super Greenland DX100 <sss>Energy software, <sss>Energy Light, EE Henry, products of Oji Paper Co., Ltd., such as Kant Excel, Excel Super B, Excel Super C, Kant Excel Bar, Utrolo Excel, Heine Excel, Dante Excel, Cosmo Ace of Nippon Oji Paper Co., Ltd. (currently Nippon Paper Industries Co., Ltd.), Semi Upper L, High Beta, High Gamma, Shiro Mari L, Hamming, White Hamming, Semi Upper HiL, Shiro Mari HiL of Kitakami Paper Manufacturing Co., Ltd., Ruby Light HREW, Pearl Soft, Ruby Light H of Mitsubishi Paper Mills Limited, Chatton, Ariso, Smash of Nakakoshi Pulp Industry Co., Ltd., Star Cherry, Cherry Super of Maruju Paper Manufacturing Co., Ltd., etc.

[0063] In addition, regarding the size and form of the recording medium that can be used in the image recording apparatus of the present invention, there is no particular limitation as long as an image can be formed by the image recording apparatus of the present invention. It may be cut to a size that is completely covered by the reaction chamber, or may be of a size that protrudes from the reaction chamber. Examples of the size that protrudes from the chemical surface treatment means of the recording medium include continuous paper wound in a roll shape, or film, etc. When using continuous paper, film, etc., it may be continuous paper, film, or continuous paper or film such as continuous forms with perforations that can be cut at predetermined intervals.

[0064] When the recording medium is of a size that is completely covered by the reaction chamber, it is not necessary to continuously perform the step of chemically surface-treating the recording medium and the step of applying the image forming material to the recording medium within a certain time. Since the time for chemically surface-treating the recording medium is not limited, it is also possible to gently chemically surface-treat the recording medium and then promptly apply the image forming material, etc.

[0065] However, in the case of a continuous paper, film, or the like that is rolled up and protrudes from the reaction chamber, since the step of chemically surface-treating the recording medium and the step of applying the image-forming material to the recording medium are continuously performed within a certain period of time, it is preferable to perform the chemical surface treatment at a speed according to the step of applying the image-forming material to the recording medium. In this case, since it is preferable to perform the chemical surface treatment promptly, it is preferable to use high-concentration chlorine dioxide, preferably perform light irradiation using a high-energy light source of 200 to 400 nm, and preferably perform light irradiation with a high light quantity.

[0066] <Image-forming material applying means> In the image recording apparatus of the present invention, the method of the image-forming material applying means is not particularly limited. For example, an inkjet method, an electrophotographic method, a thermal transfer method, a thermal sublimation method, a letterpress printing method, an offset printing method, a gravure printing method, or a screen printing method can be used. The image recording apparatus of the present invention can preferably use inkjet printing, gravure printing, or flexographic printing in which the viscosity of the image-forming material is low. Moreover, according to the present invention, it can also be preferably used for printing methods in which the combination of the recording medium and the image-forming material is greatly restricted, such as the inkjet method, the letterpress printing method, and the screen printing method.

[0067] - Inkjet method - When the image forming material applying means is an inkjet method, the ink droplets applied from the inkjet head to the recording medium form ink dots (hereinafter simply referred to as dots) on the surface of the recording medium. However, when a plurality of dots are adjacent and in contact, in order to minimize the surface tension of the dots, a beading phenomenon occurs in which the space between the dots coalesces and shrinks. In order to suppress the beading phenomenon, it is possible to suppress the coalescence of the dots by increasing the surface free energy contributing to the surface tension of the recording medium to increase the wettability of the ink and strengthen the dot expansion. Oxidizing the surface of the recording medium, for example, increasing the carboxyl groups, can increase the surface free energy of the recording medium and suppress the beading phenomenon.

[0068] In addition, as the carboxyl groups increase and the surface pH of the recording medium decreases, hydrogen ions, which are the counter cations of the carboxyl groups of the recording medium, are replaced by the counter cations of the anionic components such as pigments, dyes, and resin fine particles contained in the ink. As a result, the hydrophilicity decreases, and the fluidity of the ink is reduced due to aggregation and precipitation. Thus, when an image is formed by the inkjet method, by controlling the aggregability and penetrability of the ink pigment, it is possible to improve the roundness of the dots, prevent the dots from coalescing, and expand the sharpness and color gamut of the dots. As a result, it is possible to suppress the dot coalescence phenomenon accompanied by liquid flow and the bleed phenomenon accompanied by irregular spreading of the ink droplets, and to perform high-quality image formation.

[0069] Furthermore, in a recording medium such as coated paper that is hydrophilic inside and hydrophobic on the surface, by reducing the surface hydrophobicity by chemical surface treatment to make it hydrophilic, it is possible to promote the penetration of the ink components into the recording medium, not only reducing the beading phenomenon and the bleed phenomenon, but also promoting the fixing and drying of the ink on the surface of the recording medium. Thus, in the image recording apparatus of the present invention, even if the image forming material applying means is an inkjet method, the beading phenomenon and the bleeding phenomenon can be suppressed, and good image formation can be achieved. Further, by making the aggregated thickness of the pigment on the recording medium thin and uniform, the amount of ink droplets can be reduced, the ink drying energy can be reduced, and the cost can also be reduced.

[0070] In addition, when the image forming material applying means is an inkjet method, a line type inkjet method equipped with a line type head, a serial type (shuttle type) inkjet method in which a carriage scans, or the like may be used.

[0071] Further, when the recording medium is chemically surface-treated, the wettability of the ink with respect to the recording medium is improved. Therefore, when image formation is performed by an inkjet method, the dots of the applied ink spread, and an image different from the assumed formed image with respect to the recording medium that has not been chemically surface-treated may be formed. Therefore, for example, when image formation is performed by an inkjet method on a chemically surface-treated recording medium, by reducing the ink ejection voltage for ink application to reduce the amount of ink droplets, it is possible to prevent an image different from the assumed formed image with respect to the recording medium that has not been chemically surface-treated from being formed. Further, by forming an image in this way, the amount of ink droplets can be reduced and the cost can be reduced.

[0072] <<Image Forming Material>> The image forming material that can be used in the image recording apparatus of the present invention is not particularly limited. For example, solvent-based ink, ultraviolet curable ink, aqueous ink, toner, or sublimation dye can be mentioned. Further, image formation can also be performed using a thermal film.

[0073] When the image forming material applying means of the image recording apparatus of the present invention is an inkjet method, ink can be used as the image forming material. Specifically, solvent-based ink, ultraviolet curable ink, or aqueous ink can be used. In the case of the image recording apparatus of the present invention, even if the image forming material is a liquid such as aqueous ink, problems caused by wettability and adhesion to the recording medium in image formation are less likely to occur, and images can be formed well.

[0074] When the image forming material applying means is an electrophotographic method, toner can be used; when it is a thermal transfer method, a thermal film can be used; when it is a thermal sublimation method, a sublimation dye can be used; and in various other printing methods, ink can be used as the image forming material.

[0075] In the case of stencil printing, which is a type of screen printing, flexographic printing, which is a type of letterpress printing, or gravure printing, where aqueous ink can be used as the image forming material, the wettability of the ink on the recording medium can be improved by chemical surface treatment in the image recording apparatus of the present invention. Therefore, the effects of the present invention are easily exhibited, and high-quality images can be provided. Also, even when forming an image on a recording medium with poor ink wettability, such as an olefin film, using ultraviolet curable ink, not only the wettability of the ink on the recording medium but also the adhesion can be improved by chemical surface treatment in the image recording apparatus of the present invention. Therefore, the durability of the image formed on the recording medium can be improved.

[0076] <Other means> The image recording apparatus of the present invention may have other means in addition to the above. Examples of the other means include a loading means for loading the recording medium into the image recording apparatus of the present invention, an unloading means for unloading the recording medium from the image recording apparatus of the present invention, a drying means for drying the recording medium, an image recording apparatus control means for controlling the image recording apparatus, a cleaning means for cleaning the surface of the recording medium after chemical surface treatment, an image reading means for reading the image formed on the recording medium, various detection means, and the like. For the loading means or the unloading means, members that can be used for moving the recording medium, such as a motor, a cable, a stage, etc., may be used. The position where the image reading means is provided may be upstream or downstream of the drying means on the conveyance path of the recording medium.

[0077] The image recording apparatus of the present invention can be applied to various image recording apparatuses, and can be particularly preferably applied to, for example, printers, facsimile apparatuses, copying apparatuses, printer / fax / copy multifunctional machines, and the like.

[0078] Here, an example of the image recording apparatus according to the present invention will be described with reference to FIGS. 1 to 8. In each drawing, the same reference numerals are given to the same constituent parts, and redundant explanations may be omitted. Further, the number, position, shape, etc. of the following constituent members are not limited to these embodiments, and can be the preferred number, position, shape, etc. for implementing the present invention.

[0079] FIG. 1 is a schematic view showing an example of the image recording apparatus according to an embodiment of the present invention as viewed from the side, front, and top. (A) of FIG. 1 shows a state of the image recording apparatus 1 as viewed from the side. The side of the image recording apparatus 1 shown in FIG. 1 refers to the Y-Z plane of the image recording apparatus 1. (B) of FIG. 1 shows a state of the image recording apparatus 1 as viewed from the front. The front of the image recording apparatus 1 shown in FIG. 1 refers to the X-Z plane of the image recording apparatus 1. (C) of FIG. 1 shows a state of the image recording apparatus 1 as viewed from the top. The top of the image recording apparatus 1 shown in FIG. 1 refers to the X-Y plane of the image recording apparatus 1.

[0080] The image recording apparatus 1 in FIG. 1 includes a processing table 130 that adsorbs and fixes the recording medium 20, a linear stage 131 that fixes the processing table 130, a linear motor 133 that transports the linear stage 131 to under the reaction chamber 151 or the head module 132, and a linear stage cable 134 that connects the linear stage 131 and the linear motor 133. In the head module 132 which is an image forming unit, for example, full line type head arrays K, C, M, Y for four colors (hereinafter referred to as "head array" when not distinguishing colors) are arranged from the upstream side in the medium transport direction. The head array is formed by arranging image forming material applying heads (hereinafter simply referred to as "heads") in a staggered manner on a base member, but is not limited thereto.

[0081] The head array is an image forming material applying means, and applies image forming materials of black K, cyan C, magenta M, and yellow Y to the recording medium being transported respectively. Note that the types and numbers of colors are not limited to this. That is, it may further have heads corresponding to green G, red R and other colors, or may have only a head for black K. The head module 132 includes an ink tank for supplying ink to each head, control means for electrically controlling the head, pressure adjusting means for adjusting and stabilizing the pressure of the ink supplied to the head, etc., which are used for discharging ink other than the head array. The water level and pressure in the tank are adjusted so that the pressure of the ink applied to each head becomes an appropriate value. On the side intersecting the moving direction of the linear motor 133, a maintenance module 135 is provided beside the head module 132. The maintenance module 135 is provided with a cap that pairs with the head provided in the head module 132. There is a waste liquid port at the bottom of the cap, which is connected to a suction pump 136 and a waste liquid tank 137 via individual valves.

[0082] The cap is provided so that it can suppress the drying of the head by adhering to the head when image formation is not being performed, and can suck to discharge the thickened ink and air bubbles in the head and maintain the applicability of the image forming material. There is a wiper between the head and the cap in the maintenance module 135. The wiper is provided to wipe the head nozzle surface to which ink has adhered by suction with the cap, form a meniscus of the nozzle, and keep the head nozzle surface clean.

[0083] Figure 2 is a schematic diagram showing an example of a series of operations for chemically surface-treating a recording medium in an image recording apparatus according to an embodiment of the present invention. First, a certain amount of chlorine dioxide gas is generated from a chlorine dioxide gas source, and the suction pump at the tip of the exhaust pipe 138 is operated. The recording medium 20 is fixed to the processing table 130, and the processing table 130 moves to a position directly below the reaction chamber 151 (Fig. 2(a)). The reaction chamber 151 descends and comes into close contact with the processing table 130 while crushing the nip member 139 (Fig. 2(b)). The exhaust valve provided in the exhaust pipe 138 is opened to exhaust the air in the sealed space composed of the reaction chamber 151 and the processing table 130 to create a vacuum (Fig. 2(c)). The exhaust valve is closed and the light source 112 is turned on. The chlorine dioxide gas valve provided in the chlorine dioxide gas pipe 140 is opened to fill the inside of the reaction chamber 151 with a gas containing chlorine dioxide (Fig. 2(d)). After reacting for a predetermined time, the light source 112 is turned off. The chlorine dioxide gas valve is closed and the exhaust valve is opened to exhaust the gas in the reaction chamber 151 to create a vacuum (Fig. 2(e)). The air valve provided in the air pipe 141 is opened to ventilate the inside of the reaction chamber 151 to wash away the gas containing chlorine dioxide and the reaction residue (Fig. 2(f)). The exhaust valve is closed to make the pressure inside the reaction chamber 151 equal to the atmospheric pressure (Fig. 2(g)). Close the air valve, raise the reaction chamber 151 to a position where it does not interfere with the recording medium 20, and move the recording medium 20 to the next process ((h) in Fig. 2).

[0084] Fig. 3 is a schematic diagram showing an example of a series of processes for performing chemical surface treatment and applying an image forming material to a recording medium in an image recording apparatus according to an embodiment of the present invention. Place the recording medium 20 on the processing table 130 provided on the linear stage 131, and fix the recording medium 20 to the processing table 130 by operating the electrostatic chuck. Then, the linear stage 131 moves from the home position (L0) at a speed v1 and stops at a position directly below the reaction chamber 151 (L1) ((a) in Fig. 3). The chemical surface treatment apparatus descends to the treatment table 130 and performs chemical surface treatment on the recording medium 20 ((b) in Fig. 3). After the reaction chamber 151 rises and stops at a non-interfering position, it accelerates from the position directly below the reaction chamber 151 (L1) to a speed v2 and moves to the printing start position (L2) ((c) in Fig. 3). While maintaining the speed v2, apply image forming materials of black K, cyan C, magenta M, and yellow Y to the recording medium 20 being conveyed and move to the image forming end position (L3) ((d) in Fig. 3). Move while decelerating to the stop position (L4) ((e) in Fig. 3). The linear stage 131 moves from the stop position (L4) to the home position (L0) at a speed v1 and stops. Stop the electrostatic chuck at the home position (L0) and recover the recording medium 20 ((f) in Fig. 3).

[0085] The head module 132 can move vertically by an elevating mechanism and has a moving mechanism that can move horizontally up to the upper part of the maintenance module. After image formation, the head module 132 rises on the linear stage 131, then moves horizontally up to directly above the maintenance module, stops at a position where each head and the cap correspond, and descends to perform capping to suppress drying of the head.

[0086] Figure 4 is a schematic diagram of an example of a chemical surface treatment means for a recording medium in an image recording apparatus according to an embodiment of the present invention. The chemical surface treatment apparatus 100, which is a chemical surface treatment means for a recording medium, has a processing table 130 that is also part of a transport mechanism, a reaction chamber 151, and a nip member 139 that closes the outside by bringing the reaction chamber 151 and the processing table 130 into close contact. The processing table 130 is provided with an electrostatic adsorption device (electrostatic chuck), and the recording medium 20 can be fixed to the processing table 130 by placing the recording medium 20 on the processing table 130 and operating the electrostatic chuck. The method of fixing the recording medium to the processing table 130 is not limited to electrostatic adsorption, and fixing by clamping with clips or using vacuum suction adsorption may also be used.

[0087] An irradiation window 114 is provided at the upper part of the reaction chamber 151, and a light source 112 is provided above the irradiation window 114 above the reaction chamber 151. The light emitted from the light source 112 is irradiated into the reaction chamber 151 through the irradiation window 114 and hits the recording medium 20 on the processing table 130. The upper part of the reaction chamber 151 can be moved up and down by a lifting mechanism including the light source 112. A light diffusing plate 152 is provided between the light source 112 and the recording medium 20. The light source 112 is connected to a cooling circulation device 153 for water cooling and a light source cooling pipe 154, and the light source 112 is cooled by the circulation of cooling water through these.

[0088] The upper part of the reaction chamber 151 is directly or indirectly connected to a chlorine dioxide gas pipe 155 that supplies chlorine dioxide gas. The chlorine dioxide gas pipe 155 is provided with a chlorine dioxide gas source 101 that supplies chlorine dioxide gas, supply gas pressure gauges 156A and 156B for adjusting the gas supply amount, and chlorine dioxide gas valves 157A and 157B. Above the reaction chamber 151, a chamber internal pressure gauge 159, an air pipe 160 for taking air into the chamber, and an exhaust pipe 161 for exhausting the gas in the chamber are provided to appropriately manage the reaction conditions of the chemical surface treatment and the gas replacement. The air pipe 160 communicates with the outside air and is provided with an air valve 166 that can be opened and closed. The exhaust pipe 161 is provided with an exhaust valve 162 for controlling the exhaust in the chamber, an exhaust gas adsorption column 163 for adsorbing and removing toxic gas components in the exhaust, and an exhaust pump 164 for sucking and discharging the gas.

[0089] FIG. 5 is a block diagram showing an example of an outline of control in an image recording apparatus according to an embodiment of the present invention. The image recording apparatus control unit is composed of a CPU that controls the entire image recording apparatus, a ROM that stores fixed data such as various programs including the programs executed by the CPU, and a RAM that temporarily stores image data and the like. The image recording apparatus control unit includes a rewritable non-volatile memory NVRAM for holding data even while the power of the image forming apparatus is turned off.

[0090] The image recording apparatus control unit includes an ASIC that performs various signal processes on the image data, image processing such as sorting, and processes input / output signals for other controls. The image recording apparatus control unit includes an image formation control unit including data transfer means, drive signal generation means, and bias voltage output means for driving and controlling each head of the head unit, and a head driver composed of a drive IC for driving each head. The image recording apparatus control unit includes a supply system control unit that drives and controls a liquid feed pump and a solenoid valve group. The image recording apparatus control unit includes a maintenance system control unit that drives and controls a suction pump and a solenoid valve group connected to the cap. An operation panel for inputting and displaying information necessary for this image recording apparatus is connected to the image recording apparatus control unit. The image recording apparatus control unit has an I / O unit. The I / O unit can acquire reading data from the pattern reading unit and information from various sensors, extract information necessary for controlling the apparatus, and use it for control by the image forming control unit, the supply system control unit, the maintenance system control unit, and the control by the image forming control unit, etc.

[0091] Also, the I / O unit can control these apparatuses by exchanging information with the conveyance control unit of the recording medium and the chemical surface treatment apparatus control unit of the chemical surface treatment means for the chemical surface of the recording medium. The chemical surface treatment apparatus includes a chemical surface treatment apparatus control unit, a ROM that stores fixed data such as various programs including the program executed by the chemical surface treatment apparatus control unit, a RAM that temporarily stores image data, etc., and a rewritable non-volatile memory NVRAM for holding data even while the power supply of the apparatus is turned off. The chemical surface treatment apparatus includes an operation panel that inputs and displays information necessary for this apparatus, and the operation panel is connected to the chemical surface treatment apparatus control unit. The chemical surface treatment apparatus control unit includes an optical control unit that controls a light source. The chemical surface treatment apparatus control unit includes a reaction system control unit that controls a chlorine dioxide gas source, a supply gas regulating valve, a temperature regulating device, and an exhaust gas regulating valve. The chemical surface treatment apparatus control unit includes an exhaust system control unit that controls a fan drive motor and a gas treatment apparatus. The chemical surface treatment apparatus control unit includes an I / O unit that acquires information from a supply gas pressure gauge, a chamber internal pressure gauge, a chamber internal thermometer, and a chlorine dioxide concentration gauge. An operation panel for inputting and displaying information necessary for this apparatus is connected to the chemical surface treatment apparatus control unit via the I / O unit. Therefore, the chemical surface treatment apparatus can be driven independently of the image recording apparatus.

[0092] FIG. 6 is a schematic diagram of an example of an image recording apparatus according to an embodiment of the present invention. As shown in FIG. 6, the image recording apparatus 1 includes a loading unit 30 that loads a roll-shaped recording medium 20 along a conveyance path D1, a chemical surface treatment apparatus 100 that is a chemical surface treatment means for the recording medium, and an image forming unit 40. Also, in FIG. 6, the image forming material applying means is an inkjet method.

[0093] The image forming unit 40 includes an inkjet head 170 and a pattern reading unit 180. The pattern reading unit 180 is provided on the downstream side of the inkjet head 170. An image is formed on the surface of the recording medium 20 after chemical surface treatment by the chemical surface treatment apparatus 100 with the image forming material applied from the inkjet head 170. The pattern reading unit 180 reads and acquires the dot image of the image formed on the recording medium 20. The acquired dot image is analyzed to calculate the roundness of the dots, the dot diameter, the variation in density, etc., and based on this result, the chemical surface treatment apparatus 100 is feedback-controlled or feedforward-controlled. The image recording apparatus 1 has a drying unit 50 that dries the recording medium 20 on which an image is formed, and an unloading unit 60 that unloads the recording medium 20 on which an image is formed. Furthermore, the image recording apparatus 1 has a control unit that controls the operations of each unit.

[0094] FIG. 7 is a schematic diagram showing an example of a state in which a recording medium is chemically surface-treated in an image recording apparatus according to an embodiment of the present invention. The chemical surface treatment apparatus 100, which is a chemical surface treatment means for the recording medium, sandwiches the recording medium 20 conveyed along the conveyance path D1 between rollers 118A, 118B, 119A, and 119B so that the gas does not diffuse to the outside because chlorine dioxide gas is generated, thereby separating the inside and outside of the chemical surface treatment apparatus 100.

[0095] The chemical surface treatment apparatus 100 is provided with a reaction chamber 123 for performing chemical surface treatment, rollers 116A, 116B, 117A, and 117B that sandwich the recording medium 20 being conveyed to confine chlorine dioxide gas, separate the inside and outside of the reaction chamber 123, and carry the recording medium 20 into and out of the chamber.

[0096] There are a chlorine dioxide gas source 101 for supplying chlorine dioxide gas to the reaction chamber 123, a supply gas pressure gauge 102 for adjusting the supply amount, and a supply gas control valve 106. A chamber internal pressure gauge 103, a chamber internal thermometer 104, a chlorine dioxide concentration gauge 105, a temperature adjustment device 108, and an exhaust gas control valve 110 are provided to appropriately manage the reaction conditions of the chemical surface treatment. The chemical surface treatment is performed by controlling the irradiation direction of the light generated from the light source 112 in the chemical surface treatment apparatus 100 with a light guide plate 113 under a chlorine dioxide gas atmosphere where the temperature, pressure, and concentration are adjusted in the chamber, and irradiating the surface of the recording medium 20 with light 124 from an irradiation window 114 provided in the reaction chamber 123 that allows light to pass through.

[0097] On the chemically surface-treated recording medium 20, chlorine dioxide gas, chlorine gas generated by the reaction, and hydrochloric acid gas are adsorbed on the surface. Since the chlorine dioxide gas and reaction gas in the reaction chamber 123 are harmful substances, they are treated and exhausted within the chemical surface treatment apparatus 100. The internal air flow of the chemical surface treatment apparatus 100 takes in outside air from the intake port 111, and is discharged from the reaction chamber 123 to the outside of the apparatus through the exhaust duct 107 by an exhaust fan 120 driven by a fan drive motor 109. The outside air 122A taken in from the intake port 111 guides the adsorbed gas 122B desorbed from the recording medium 20 conveyed into the chemical surface treatment apparatus 100 to the fan side 122C, and is sucked together with the exhaust gas 122D in the reaction chamber by the exhaust fan 120. These exhaust gases are subjected to an adsorption treatment of chlorine dioxide-derived compounds by a chlorine dioxide-derived compound adsorption mechanism 121 and then exhausted 122E to the outside of the apparatus. In addition, the outside air 122A circulates inside the chemical surface treatment apparatus 100 and acts as an air flow 122F that cools the heat generated from the light source 112, and is discharged outside the chemical surface treatment apparatus 100 by the exhaust fan 120.

[0098] FIG. 8 is a schematic diagram showing another example of the state of chemically surface-treating a recording medium in an image recording apparatus according to an embodiment of the present invention. The chemical surface treatment in the chemical surface treatment apparatus 100, which is a recording medium chemical surface treatment means, is not limited to one side of the recording medium 20, and it is also possible to treat both sides. The chemical surface treatment of both sides of the recording medium 20 is performed by controlling the irradiation direction with a light guide plate 113 for the light generated from the light sources 112 installed above and below the transport path in the chemical surface treatment apparatus 100 in an atmosphere of chlorine dioxide gas whose temperature, pressure, and concentration are adjusted in the reaction chamber 123, and irradiating the surface of the recording medium 20 with the light passing through the irradiation windows 114 provided in the upper and lower reaction chambers 123.

[0099] Here, with reference to FIGS. 9 to 12, embodiments of the present invention will be specifically described. Note that the present invention is not limited to the embodiments described with reference to FIGS. 9 to 12, and various modifications can be made without departing from the gist thereof.

[0100] FIG. 9 is a flowchart showing an example of the flow of steps to be processed in an image recording apparatus according to an embodiment of the present invention. FIG. 9 shows a case where ink is used as an image forming material and the image forming material applying means is an inkjet method. As shown in FIG. 9, first, the image recording apparatus control unit identifies the type of the recording medium (step S101). The type of the recording medium may be set and input to the image recording apparatus by the user from the control panel. Alternatively, if the image recording apparatus is provided with a recording medium type detection means, the image recording apparatus control unit may identify it based on the characteristic information of the recording medium detected by this recording medium type detection means. The identification method is not limited, but based on a database consisting of the recording medium characteristic information and types, the image recording apparatus control unit may identify the type of the recording medium from the measured characteristic information, or from the AI learning that associates the recording medium characteristic information with the type of the recording medium as learning information, the image recording apparatus control unit may identify the type of the recording medium from the characteristic information measured using this AI.

[0101] Note that the recording medium type detection means may, for example, irradiate the surface of the recording medium with laser light and analyze the interference spectrum of the reflected light to identify the type, or may measure the thickness of the recording medium to identify the recording medium, or may be a barcode reader that reads a barcode including the recording medium type information formed on the surface of the recording medium. Also, the image recording apparatus control unit identifies the image formation mode (step S102). The image formation mode is, for example, the resolution of the image to be formed (600 dpi, 1200 dpi, etc.) or the image formation speed (linear speed), and may be set, for example, by the user using the input unit. Alternatively, the image formation mode may be input together with image data (raster data) from an external higher-level device (for example, the DFE 210 described later).

[0102] Next, the image recording apparatus control unit identifies the color and / or type of the ink (used ink) used for forming the target image (step S103). At that time, the color or type of the used ink may be identified for the entire image data of the image formation target, or the area of the image data may be divided for each type of used ink (or for each object included in the image data), and identified for each area. The type of ink used can be specified from, for example, the colors used in the raster data of the input image data and the type of ink set in the inkjet head or the ink tank of the ink supply unit.

[0103] The color of the ink used can be specified from, for example, the colors used in the raster data of the input image data and the color of the ink set in the inkjet head or the ink tank of the ink supply unit. Note that the color of the ink set in the inkjet head and the type of the ink (model number, etc.) may be set and input by the user to the image recording apparatus from the control panel, or a detection unit for detecting the set ink color and type may be provided in the inkjet head. Since there is an applicable recording medium type for the type of ink used, when comparing the detected recording medium type with the applicable recording medium of the used ink type and it is not applicable, a warning is displayed on the control panel for the user to confirm whether execution is necessary. Also, when the ink color used does not match the color used in the raster data, a warning is displayed on the control panel for the user to confirm whether execution is necessary.

[0104] Next, the image recording apparatus control unit specifies the amount of ink droplets during image formation (step S104). The amount of ink droplets is, for example, based on the specified resolution and linear velocity of the image formation mode, referring to the drive waveform selection table in the control unit that associates the ink type, resolution, and linear velocity with the drive waveform, selecting the drive waveform to be used, and also referring to the droplet amount table for the average ink droplet amount corresponding to the droplet size of the drive waveform to specify it. For example, in the case of black ink for coated paper, when the image formation mode is 1200 dpi and the linear velocity is 50 m / min, a dedicated drive waveform is selected, and based on the table, the ink droplet amount in the case of applying small droplets from the selected drive waveform can be specified as 2 pl (picoliters). Also, when the cyan ink image forming mode for coated paper is 600 dpi, the linear speed is 100 m / min, and the dot size is large droplets, the ink droplet volume can be specified as 15 pl (picoliters). Also, the required dot size has a dot size table corresponding to the resolution and the droplet size of the drive waveform in the control unit. The required dot size is specified by referring to the table from the resolution information and droplet size of the image forming mode. The actual dot size is the size of the droplet applied from the inkjet head or the size of the dot formed on the recording medium, and may be specified by the image recording apparatus control unit from the image information of the image to be formed.

[0105] Subsequently, the image recording apparatus control unit sets the reaction conditions for the chemical surface treatment (step S105). Set the optimal reaction conditions for the chemical surface treatment as the reaction conditions to be set. Based on the specified color and / or type of the ink used, the type of the recording medium, and the ink droplet volume, the reaction conditions for the chemical surface treatment such as gas concentration, pressure, reaction temperature, and integrated light amount of light are held in a table, and it is possible to specify the reaction conditions for the chemical surface treatment as needed.

[0106] Next, the image recording apparatus control unit controls the supply amount so as to obtain a chlorine dioxide gas concentration based on the set reaction conditions for the chemical surface treatment, and controls the predetermined temperature and the irradiation light amount of the light source, thereby performing the chemical surface treatment on the recording medium 20 (step S106). Subsequently, the image recording apparatus control unit performs image formation of a test pattern on the recording medium after the chemical surface treatment (step S107). Subsequently, the image recording apparatus control unit reads an image (dot image) of the dots formed on the recording medium after the chemical surface treatment by imaging the dots of the test pattern using the pattern reading unit (step S108).

[0107] Next, the image recording apparatus control unit detects the geometric characteristics of the dots from the read dot image (step S109). The geometric characteristics of the dots include the roundness of the dots, the dot diameter, and the density difference of the dots, and these are detected. Further, the image recording apparatus control unit may determine the state of coalescence between the dots from the read dot image. The state of coalescence between the dots can be determined, for example, by pattern recognition.

[0108] Next, the image recording apparatus control unit determines whether the quality of the formed dots is sufficient quality based on the detected roundness of the dots, the dot diameter, and the deviation of the pigment concentration in the dots, or the state of coalescence of the dots (step S110). If the quality is not sufficient (step S110; NO), the image recording apparatus control unit corrects the reaction conditions of the chemical surface treatment according to the detected geometric characteristics of the dots (step S111), returns to step S105, re-sets the reaction conditions of the chemical surface treatment, and performs analysis of the dots from the image formation of the test pattern. This correction may, for example, increase or decrease the reaction conditions of the chemical surface treatment being set by a predetermined correction value, or obtain the optimal reaction conditions of the chemical surface treatment according to the detected geometric characteristics of the dots, and re-set to this value.

[0109] On the other hand, when the dots are of sufficient quality (step S110; YES), the image recording apparatus control unit updates the optimal value of the registered reaction conditions of the chemical surface treatment based on the type of the specified recording medium, the image formation mode, and the ink used (step S112), forms the target image to be actually formed (step S113), and upon completion, ends this operation. Note that steps S101 to S112 in FIG. 9 may be executed separately from the actual image formation process (step S113). That is, the creation and update of the reaction condition table for chemical surface treatment may be performed in a separate process independent of actual image formation. For example, the user may be able to instruct the image recording apparatus to execute steps S101 to S112 before the start of the image formation process or during the image formation process. Alternatively, during the process of forming an image, a change in dot diameter may be detected, and when the detected dot diameter has changed significantly or exceeded the allowable range, the image formation process may be interrupted and steps S101 to S112 may be automatically executed. Also, steps S107 to S112 may be performed for each image formation process or at a predetermined timing, and step S113 may be executed after step S106 in actual image formation.

[0110] Also, when using roll paper as the recording medium, in steps S106 to S112, a dot image formed after chemical surface treatment may be acquired using the leading end portion of the paper guided from the paper feeding device. When using roll paper, since the properties hardly change with one roll, after adjusting the reaction conditions of chemical surface treatment using the leading end portion, stable continuous image formation can be achieved with the same settings. However, if the roll paper is not used up and stopped for a long time, the properties of the paper may change. Therefore, before resuming image formation, a dot image formed after chemical surface treatment may be acquired again using the leading end portion in the same manner and analyzed. Also, after analyzing the dot image formed after chemical surface treatment using the leading end portion to adjust the reaction conditions of chemical surface treatment, the dot image may be measured periodically or continuously to adjust the reaction conditions of chemical surface treatment. This makes it possible to perform more detailed and stable control.

[0111] Also, in FIG. 9, conditions are determined using a general method, but it is not limited to this method. For example, the reaction conditions of the first chemical surface treatment may be set as the minimum value, and based on the analysis result of the dot image of the obtained test pattern, the reaction conditions of chemical surface treatment may be changed step by step. When changing the reaction conditions of the chemical surface treatment, for example, increasing the irradiation light amount of light step by step from the minimum value, the irradiation light amount of the light source in FIG. 7 may be changed to increase step by step, or the conveyance speed of the recording medium, that is, the irradiation time of light, may be changed.

[0112] The test pattern TP formed as described above is read by the pattern reading unit 180 in FIG. 7 in step S108 of FIG. 9.

[0113] FIG. 10 is a schematic diagram showing an example of a state of reading a pattern in an image recording apparatus according to an embodiment of the present invention. As shown in FIG. 10, a reflection type two-dimensional sensor including, for example, a light emitting unit 182 and a light receiving unit 183 is used for the pattern reading unit 180. The light emitting unit 182 and the light receiving unit 183 are arranged, for example, in a housing 181 arranged on the dot DT forming side with respect to the recording medium 20. An opening is provided on the recording medium 20 side of the housing 181, and the light irradiated from the light emitting unit 182 is reflected on the surface of the recording medium 20 and enters the light receiving unit 183. The light receiving unit 183 forms an image of the reflected light reflected on the surface of the recording medium 20. Since the light amount of the imaged reflected light changes between a portion where the formed image (dot DT of the test pattern TP) exists and a portion where it does not exist, it is possible to detect the dot shape and the image density inside the dot based on the reflected light amount detected by the light receiving unit 183. Note that the configuration of the pattern reading unit 180 and its detection method can be variously changed as long as it is possible to detect the test pattern TP formed on the recording medium 20. Further, the pattern reading unit 180 may include a reference pattern display unit 184 having a reference pattern 185 as means for calibrating the light amount of the light emitting unit 182 and the read voltage of the light receiving unit 183.

[0114] The reference pattern display unit 184 has a rectangular parallelepiped shape made of a predetermined recording medium such as plain paper, and a reference pattern 185 is attached to one of its surfaces. When calibrating the light emitting unit 182 and the light receiving unit 183, the reference pattern display unit 184 rotates so that the reference pattern 185 faces the light emitting unit 182 and the light receiving unit 183 side, and when calibration is not performed, it flips so that the reference pattern 185 does not face the light emitting unit 182 and the light receiving unit 183 side.

[0115] Also, by reading the formed image and analyzing this image, the reaction conditions in the chemical surface treatment can be adjusted so that the dot diameter for each ink application amount becomes the target dot diameter, thereby enabling higher image quality. Also, since the pigment concentration of the dots can be detected based on the amount of reflected light, a dot image can be captured and the concentration inside the dots can be measured. The density unevenness is measured by calculating the variation dispersion of the density values through statistical calculation. Also, by selecting the reaction conditions of the chemical surface treatment so that the calculated density unevenness is minimized, it becomes possible to prevent the turbidity of the pigment due to the coalescence of the dots, and thereby further improve the image quality. Whether to prioritize dot diameter control, prioritize suppression of density unevenness, or prioritize improvement of roundness may be configured so that the user can switch modes according to the target image quality.

[0116] As described above, the reaction conditions of the chemical surface treatment can be controlled according to the color and type of the ink so that the roundness of the dots or the unevenness of the pigment in the dots is reduced, or the dot diameter becomes the target size. Thereby, while realizing the uniformity of the dot diameter and energy saving, it becomes possible to form an image with high image quality. Also, even if the type or properties of the recording medium 20 are changed or the image forming speed is changed, since it is possible to perform stable chemical surface treatment, it becomes possible to stably realize good image recording.

[0117] FIG. 11 is an example of a graph showing the relationship between the ink application amount and the formed image density in an image recording apparatus according to an embodiment of the present invention. In FIG. 11, the solid line C1 shows the relationship between the ink application amount and the formed image density when image formation is performed by an inkjet method on a chemically surface-treated recording medium, and the broken line C2 shows the relationship between the ink application amount and the formed image density when image formation is performed by an inkjet method on a recording medium that has not been chemically surface-treated. Also, the alternate long and short dash line C3 shows the ink reduction rate of the solid line C1 with respect to the broken line C2. As can be seen from the comparison between the solid line C1 and the broken line C2 in FIG. 11 and the alternate long and short dash line C3, by subjecting the recording medium to chemical surface treatment before image formation, effects such as improvement in the roundness of dots, dot enlargement, and density uniformity of the pigment within the dots reduce the ink application amount required to obtain the same image density. Also, by subjecting the recording medium to chemical surface treatment before image formation, the thickness of the pigment applied to the recording medium becomes thinner, so that the color saturation can be improved and the color gamut can be expanded. Furthermore, as a result of the reduction in the ink amount, the drying energy of the ink can also be reduced, so that an energy-saving effect can be obtained. Also, the formed image data may be input, for example, from an external host device.

[0118] FIG. 12 is a schematic diagram showing an example of an image recording system including an image recording apparatus according to an embodiment of the present invention. As shown in FIG. 12, in addition to the image recording apparatus 1, the image recording system 2 includes a host device 200, a printer controller (DFE: Digital Front End) (hereinafter referred to as DFE) 210, and an interface controller (MIC: Mechanism I / F Controller) (hereinafter referred to as MIC) 220. The host device 200 creates, for example, image data to be formed into an image, and outputs this as vector-form image data to the DFE 210.

[0119] The host device 200 may be, for example, a PC (Personal Computer). The DFE 210 communicates with the image recording apparatus 1 via the MIC 220 and controls the formation of an image in the image recording apparatus 1. The DFE 210 may be configured by, for example, a PC. In addition, a host device such as another PC can be connected to the DFE 210. The DFE 210 receives vector format image data from the host device 200, interprets this image data, and converts the vector format image data into raster format image data. At that time, the DFE 210 converts a color space expressed in an RGB format or the like into a color space such as a CMYK format.

[0120] The DFE 210 transmits the generated raster format image data to the image recording apparatus 1 via the MIC 220. Although the case where the DFE 210 is configured by one PC has been illustrated, the present invention is not limited thereto. For example, the DFE 210 may be incorporated in the host device 200, or may be mounted on the image recording apparatus 1 together with the MIC 220. Furthermore, when the image recording system 2 is a cloud computing system, the DFE 210 may be arranged in a computer on a network, may be arranged between the network and the image recording apparatus 1, or may be arranged in the image recording apparatus 1.

Embodiment

[0121] Hereinafter, the present invention will be described more specifically by giving several specific examples, but the present invention is not limited thereto. In the following analysis and evaluation, the case where a recording medium after chemical surface treatment is used is an example, and the case where a recording medium before chemical surface treatment is used is a comparative example.

[0122] (Recording medium) As the recording medium, a PP film 1 (Pyren film P1011, manufactured by Toyobo Co., Ltd.), a PET film 1 (Lumirror #50-T60, manufactured by Toray Industries, Inc.), a polyvinyl chloride film 1 (IJ180, manufactured by 3M Japan Ltd.), and a polyvinyl chloride film 2 (GIY-11Z5 Gloss, manufactured by Gross Rintec Sign Systems Co., Ltd.), which are liquid-repellent, were used.

[0123] (Chemical surface treatment of the recording medium) 10 g of sodium chlorite (manufactured by Kanto Chemical Co., Inc.) and 500 mL of high-purity water were placed in a glass container. After dissolving sodium chlorite in high-purity water, 4.5 mL of a hydrochloric acid aqueous solution (manufactured by Kishida Chemical Co., Ltd.) with a concentration of 35 - 37% was added, and the prepared mixture was allowed to stand for 24 hours. It was confirmed that absorption derived from chlorine dioxide was observed at around 350 - 360 nm by measuring the UV spectrum of the mixture after 24 hours with a spectrophotometer (U-3900H, manufactured by Hitachi High-Tech Corporation). A glass irradiation window was provided so that light could enter the inside of the container, and a sealed container was prepared by blocking the outside air. Each recording medium and the above mixture placed in a beaker serving as a chlorine dioxide gas source were placed therein. Through the irradiation window, ultraviolet light with a light source wavelength of 365 nm was irradiated onto the surface of the recording medium inside from the outside of the container at 200 mW / cm 2 for 5 minutes.

[0124] <Infrared absorption spectrum analysis of the surface of the recording medium before and after chemical surface treatment> Each chemically surface-treated recording medium was taken out from the sealed container, and the chemical composition of the surface of each recording medium was evaluated by infrared absorption spectrum analysis using a Fourier transform infrared spectrometer (Frontier, manufactured by PerkinElmer) under the following measurement conditions. Since a diamond crystal was used for the measurement, information with a depth of 4 μm from the surface layer was obtained. (Measurement conditions) · Measurement mode: ATR (diamond) · Resolution: 4 cm -1 · Detector: TGS detector · Measurement wavelength range: 4000 - 650 cm -1 · Integration count: 4 times

[0125] As a representative analysis result, Fig. 13 shows a graph showing the infrared absorption spectrum analysis results of the surface of the PP film 1 before and after chemical surface treatment. When comparing the infrared absorption spectra of the PP film 1 before and after chemical surface treatment, for the PP film 1 before chemical surface treatment, in the PP film 1 after chemical surface treatment, the carbonyl group (-C(=O)-) contained in the ester group (-COOR), carboxyl group (-COOH), etc. corresponds to 1700 cm -1 absorption and the absorption corresponding to alcoholic hydroxyl group (C-OH) at 3300 cm -1 showed a relative increase. The results of analyzing the surface chemical composition of the PET film 1, polyvinyl chloride film 1, and polyvinyl chloride film 2 were also the same as those of the PP film 1. From this result, it was confirmed that the C-H bond contained in the alkyl group etc. on the surface of the recording medium was oxidized to a carboxyl group (-COOH), and the hydrophilic functional group on the surface of the recording medium increased.

[0126] <X-ray photoelectron spectroscopy analysis of the surface of the recording medium before and after chemical surface treatment> Each of the chemically surface-treated recording media was taken out from a sealed container, and for the chemical composition of the surface of each of the recording media, X-ray photoelectron spectroscopy analysis (XPS) was performed using an X-ray photoelectron spectrometer (manufactured by Thermo Fisher Scientific, K-Alpha) under the following measurement conditions to examine the elemental concentration on the surface of the recording medium. Each sample obtained by cutting out each of the recording media before and after chemical surface treatment into 10 mm squares was pasted with carbon double-sided tape on the surface opposite to the chemically surface-treated surface, and attached and fixed to the sample stage. (Measurement conditions) · X-ray: Al mono · 12 kV · 6 mA · Analysis area: 400 μmφ · Neutralization gun: ON · Pass energy: 50 eV ·Energy step: 0.2 eV

[0127] The identification of the peaks in the measured XPS spectra was performed using the analysis software CasaXPS. The identification of the elements from which each XPS peak originated was performed using the element library provided by Thermo Fisher Scientific. The calculation of the element concentrations from the measured XPS spectra was performed using the analysis software CasaXPS. The elements used for the calculation of the element concentrations were C 1s, N 1s, O 1s, and Cl 2p. The baseline generation of the background for each element was performed by the Tougaard method. For the lateral adjacent averaging during baseline generation, the average values of any three points in the energy range (horizontal axis) at the start and end points of the XPS spectrum data obtained from one measurement point of each of the above-mentioned recording medium samples were used. For the relative sensitivity factor RSF during the calculation of the element concentrations, the one provided in the element library by Thermo Fisher Scientific was used. The average values of the element concentrations of C, N, O, and Cl for each sample were calculated from the element concentrations measured at any three points in a region sufficiently far from the region already used for the XPS measurement. As a representative analysis result, the analysis result of PP film 1 is shown in Table 1. For the surface of any of the recording media, an increase in the element concentration of oxygen from O1s was confirmed before and after the chemical surface treatment, and it was confirmed that the surface of the recording medium was oxidized. Also, for PET film 1, polyvinyl chloride film 1, and polyvinyl chloride film 2, similar to PP film 1, an increase in the element concentration of oxygen from O1s was confirmed before and after the chemical surface treatment, and it was confirmed that the surface of the recording medium was oxidized.

[0128]

Table 1

[0129] <Evaluation of the landing behavior of ink droplets on the surface of the recording medium before and after chemical surface treatment> As the recording medium, PP film 1, PET film 1, polyvinyl chloride film 1, polyvinyl chloride film 2, offset printing coated paper 1 (OK top coat gloss + 127.9 gsm, manufactured by Oji Paper Co., Ltd.) were used. The inkjet method was used for the recording medium image forming material applying means. As the image forming material, aqueous pigment ink (cyan ink for RICOH Pro L5160e, Ricoh Company, Ltd.) and aqueous pigment ink (cyan ink for RICOH Pro VC70000, Ricoh Company, Ltd.) were used. By comparing the landing behavior of ink droplets on these surfaces before and after chemical surface treatment, the effect of the above chemical surface treatment was evaluated. Note that aqueous pigment ink (cyan ink for RICOH Pro L5160e, Ricoh Company, Ltd.) was used for PP film 1, PET film 1, polyvinyl chloride film 1, and polyvinyl chloride film 2, and aqueous pigment ink (cyan ink for RICOH Pro VC70000, Ricoh Company, Ltd.) was used for offset printing coated paper 1.

[0130] For the observation and evaluation of the landing behavior of ink droplets, a landing behavior visualization device (an experimental device described in "Measurement of the thickening process of ink droplets landing on the medium" (Harada, Journal of the Japan Society for Imaging Science and Technology, Vol. 59, No. 5)) was used. In the landing behavior visualization device, while flying ink droplets toward the recording medium, the inkjet head is scanned, and the state of ink droplets being successively applied to the recording medium can be photographed and recorded with a high-speed high-magnification camera. Also, by analyzing the recorded video image processing, the temporal changes in the shape and state of the ink droplets can be quantified.

[0131] For each recording medium, the dots were evaluated after dropping 40 pL per drop. Regarding the ink droplets that enter the field of view of the imaging optical system, a moving image from just before the landing of the first landing ink droplet to a time of 1 second or more after the landing of the last landing ink droplet was recorded at a shooting speed of 20,000 frames per second (fps). For each ink droplet shooting moving image, the temporal changes in the dot diameter and contact angle of the ink droplets after being applied to the recording medium were calculated by image processing. The ink ejection cycle for ink application was 160 Hz, the scanning speed of the actuator was 20 mm / s, and the interval between the landing ink droplets was set to 125 μm.

[0132] Figures 14 to 18 are graphs showing the temporal changes in the dot diameter of the ink droplets landed on the surface of each recording medium before and after chemical surface treatment. In Figures 14 to 18, the horizontal axis represents the elapsed time after the ink droplets landed on the recording medium, and the vertical axis represents the dot diameter of the ink droplets. The average values for 10 trials are graphed. From each graph, the wetting spread behavior depending on the presence or absence of chemical surface treatment on each recording medium can be understood. In Figures 14 to 18, the results before chemical surface treatment are shown as (I), and the results after chemical surface treatment are shown as (II).

[0133] Figures 19 to 23 are graphs showing the temporal changes in the contact angle of the ink droplets landed on the surface of each recording medium before and after chemical surface treatment. In Figures 19 to 23, the horizontal axis represents the elapsed time after the ink droplets landed on the recording medium, and the vertical axis represents the contact angle of the ink droplets. The average values for 10 trials are graphed. From each graph, the wetting spread behavior depending on the presence or absence of chemical surface treatment on each recording medium can be understood. In Figures 19 to 23, the results before chemical surface treatment are shown as (I), and the results after chemical surface treatment are shown as (II).

[0134] As the dot area expands, the surface area where the ink contacts the outside air increases, promoting the volatilization of the ink solvent and making it easier to dry. Therefore, the faster the ink droplet spreads, the easier it is for the ink to dry and adhere to the recording medium, suppressing the coalescence between dots and the flow of ink into adjacent dots, indicating that the beading phenomenon and the bleeding phenomenon can be suppressed. From FIGS. 14 to 18, it was found that in any of the above recording media, compared with those before chemical surface treatment, the dot diameter of the ink droplets spread in a shorter time for those after chemical surface treatment, and it spread rapidly in the initial stage up to 50 msec after landing. Also, from FIGS. 19 to 23, it was shown that in any of the above recording media, compared with those before chemical surface treatment, the contact angle of the ink droplets became lower in a shorter time for those after chemical surface treatment, and it spread rapidly immediately after the ink droplets landed. From the above, it was shown that the recording medium after chemical surface treatment can suppress the beading phenomenon and the bleeding phenomenon.

[0135] Also, FIG. 24 is a photographed image showing the landing behavior of ink droplets landed on the surfaces of polyvinyl chloride films 1 and 2 before and after chemical surface treatment. It is a camera image when the ink droplets are landed on the polyvinyl chloride film in order from right to left, and it was photographed so that the elapsed time after landing is longer on the right and shorter on the left. In FIG. 24, the change in the dot diameter when ink droplets are landed on polyvinyl chloride films 1 and 2 can be seen. (A) in FIG. 24 shows the state of photography for polyvinyl chloride film 1, and (B) shows the state of photography for polyvinyl chloride film 2.

[0136] In polyvinyl chloride films 1 and 2, it can also be seen from the image that for those after chemical surface treatment, the dot diameter is larger and the contact angle between the polyvinyl chloride film and the ink is lower than that before chemical surface treatment. From this, it was shown that by performing the above chemical surface treatment, the ink droplets can spread rapidly and the wet spreading of the ink droplets can be increased.

[0137] Furthermore, regarding the behavior of ink landing on polyvinyl chloride films 1 and 2 heated to 50°C, the dot diameter of the ink droplets was measured in the same manner as above. Figure 25 is a graph showing the change over time in the dot diameter of ink droplets landed on the surface of polyvinyl chloride film 1 at 50°C before and after chemical surface treatment. Figure 26 is a graph showing the change over time in the dot diameter of ink droplets landed on the surface of polyvinyl chloride film 2 at 50°C before and after chemical surface treatment. In Figures 25 and 26, the results before chemical surface treatment are shown as (I), and the results after chemical surface treatment are shown as (II).

[0138] Even in polyvinyl chloride films 1 and 2 before and after chemical surface treatment heated to 50°C, the dot diameter of the films after chemical surface treatment spread more quickly than those before chemical surface treatment. Also, after chemical surface treatment, the dots had spread completely within 10 msec. Therefore, it was shown that the wettability of the chemically surface-treated recording medium was improved regardless of its temperature.

[0139] From the above results, it was shown that by performing surface modification of the recording medium using chlorine dioxide and light, the wettability was improved regardless of the type of recording medium.

[0140] <Comparison of Images Formed on Recording Media Before and After Chemical Surface Treatment> Next, polyvinyl chloride films 2 before and after chemical surface treatment were prepared, and image formation was performed using an inkjet printer. The chemical surface treatment of polyvinyl chloride film 2 was performed in the same manner as above. The exterior of an inkjet printer (IPSiO GX-e5500, Ricoh Company, Ltd.) that moves the head relative to the recording medium for serial printing was removed, a rear multi-feed feeder was attached, and the ink supply path including the head was washed by passing pure water through it. The apparatus was used as an evaluation image recording apparatus after thoroughly passing the cleaning liquid until the cleaning liquid no longer became colored and then draining the cleaning liquid from the apparatus. Also, as the image forming material, each of the black, cyan, magenta, and yellow inks (for RICOH Pro L5160e, Ricoh Company, Ltd.) was degassed by stirring for 30 minutes under a reduced pressure condition of 5 to 10 Pa to obtain the evaluation ink. Also, these inks were filled into ink cartridges (for IPSiO GX-e5500, Ricoh Company, Ltd.) to obtain the evaluation ink cartridges. The evaluation ink cartridges were set in the above evaluation image recording apparatus, and the filling operation to the nozzles was performed. It was confirmed that all nozzles were filled with the evaluation ink and no abnormal images were output. After selecting the glossy paper clean mode with the driver attached to the printer, the color matching off was set as the printing mode in the user settings. In this mode, the ink application amount on the recording medium for the solid image was adjusted by changing the driving voltage of the head so that it became 20 g / m 2

[0141] The polyvinyl chloride film 2 before and after chemical surface treatment, with double-sided tape attached to the surface opposite to the surface to be chemically surface-treated, was fixed on the PPC plain paper (My Paper, Ricoh Company, Ltd.) with double-sided tape, and the test image 1 created in Microsoft Office365 Word was formed on the polyvinyl chloride film 2. Figure 27 is a photograph of the images formed on the surface of the polyvinyl chloride film 2 before and after chemical surface treatment. The upper part of Figure 27 is an enlarged photograph of the formed test image 1.

[0142] Regarding the test image 1, in the one before chemical surface treatment, dot coalescence occurred and spots were generated in the solid part, and gradation was observed. However, in the one after chemical surface treatment, since the wettability on the recording medium was improved, dot coalescence was suppressed and a uniform image without gradation was obtained. Also, in the one before chemical surface treatment, bleeding between colors was large and a bleeding area with color mixing occurred. However, in the one subjected to chemical surface treatment, since dot coalescence was suppressed, dot coalescence between colors was suppressed and color boundary bleeding was reduced.

[0143] ​Furthermore, in the same manner as described above, a test image 2 of a white character image with 6 points on a black background was formed. The lower part of FIG. 27 is an enlarged photograph of the formed test image 2. Before the chemical surface treatment, the white characters were blurred due to non-uniform wetting and the readability was poor. However, after the chemical surface treatment, the white characters were not blurred due to uniform wetting and the readability was excellent.

[0144] From the above results, it was shown that an image recording apparatus capable of surface modification of a recording medium using chlorine dioxide and light can form an image well regardless of the type of the recording medium.

[0145] Examples of the aspects of the present invention are as follows. <1> An image recording apparatus including a recording medium chemical surface treatment means having a chlorine dioxide supply unit that supplies chlorine dioxide to a recording medium and a light irradiation unit that irradiates light, and an image forming material applying means that applies an image forming material to the recording medium chemically surface-treated by the recording medium chemical surface treatment means. <2> The image recording apparatus according to <1>, wherein the image forming material applying means is an inkjet method. <3> The image recording apparatus according to <1> or <2>, wherein the image forming material is aqueous ink. <4> The image recording apparatus according to any one of <1>, <2>, and <3>, wherein the recording medium chemical surface treatment means has a shielding mechanism that blocks outside air. <5> The image recording apparatus according to any one of <1>, <2>, <3>, and <4>, wherein the recording medium chemical surface treatment means has an exhaust mechanism. <6> The image recording apparatus according to <5>, wherein the exhaust mechanism has a chlorine dioxide-derived compound adsorption mechanism that adsorbs a chlorine dioxide-derived compound. <7> The image recording apparatus according to any one of <1>, <2>, <3>, <4>, <5>, and <6>, wherein the substance supplied by the chlorine dioxide supply unit is a gas containing chlorine dioxide. <8>The image recording apparatus according to any one of <1>, <2>, <3>, <4>, <5>, <6>, <7> above, wherein the surface of the recording medium for applying the image forming material has poor liquid absorption properties.

[0146] According to any one of the image recording apparatuses from <1> to <8> above, various problems in the prior art can be solved, and the object of the present invention can be achieved.

Explanation of Reference Numerals

[0147] 1 Image recording apparatus 2 Image recording system 20 Recording medium 100 Chemical surface treatment apparatus 101 Chlorine dioxide gas source 112 Light source 113 Light guide plate 114 Irradiation window 121 Chlorine dioxide-derived compound adsorption mechanism 123 Reaction chamber 124 Light 138 Exhaust pipe 139 Nip member 140 Chlorine dioxide gas pipe 141 Air pipe 151 Reaction chamber 152 Light diffusion plate 153 Cooling circulator for water cooling 154 Pipe for light source cooling 155 Chlorine dioxide gas pipe 160 Air pipe 161 Exhaust pipe 163 Exhaust gas adsorption column 164 Exhaust pump 165 Air pipe 170 Inkjet head

Prior Art Documents

Patent Documents

[0148]

Patent Document 1

Claims

1. A recording medium chemical surface treatment means having a chlorine dioxide supplying unit that supplies chlorine dioxide to the recording medium and a light irradiating unit that irradiates light; an image forming material applying means for applying an image forming material to the recording medium that has been chemically surface-treated by the recording medium chemical surface treating means; An image recording device comprising:

2. 2. The image recording apparatus according to claim 1, wherein the image forming material applying means is of an ink-jet type.

3. 2. The image recording apparatus according to claim 1, wherein the image forming material is a water-based ink.

4. 3. The image recording apparatus according to claim 2, wherein the recording medium chemical surface treatment means has a shielding mechanism for blocking outside air.

5. 2. The image recording apparatus according to claim 1, wherein the recording medium chemical surface treatment means has an exhaust mechanism.

6. 6. The image recording apparatus according to claim 5, wherein the exhaust mechanism has a chlorine dioxide-derived compound adsorption mechanism that adsorbs compounds derived from chlorine dioxide.

7. 2. The image recording apparatus according to claim 1, wherein the substance supplied by the chlorine dioxide supply unit is a gas containing chlorine dioxide.

8. 2. The image recording apparatus according to claim 1, wherein the recording medium has a surface onto which the image forming material is applied that is poorly liquid-absorbent.

Images