Recording method and recording device

Abstract

To provide a recording method capable of yielding recorded matter with superior image quality.SOLUTION: There is provided a recording method for a recording medium, the recording medium including a seal region bonded by heat sealing and a heating region with which heating means of the heat sealing comes into contact, the seal region and the heating region being disposed on front and back sides relative to each other in the recording medium, the method comprising: an image forming step in which a coloring ink composition is discharged from an inkjet head and adhered to the heating region to form an image; and a protective layer forming step in which a protective composition is discharged from an inkjet head and adhered to the image formed on the heating region to form a protective layer.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a recording method and a recording apparatus. [Background technology]

[0002] The recording method of ejecting ink from an inkjet head is capable of recording high-resolution images using a relatively simple device, and has been rapidly developing in various fields. For example, recording is performed by ejecting ink from an inkjet head onto recording media such as packaging substrates. Printing on such recording media includes reverse printing, in which printing is performed on the side of the recording media facing the contents, and front printing, in which printing is performed on the side of the recording media opposite the contents. In the case of reverse printing, a laminate is applied to the printed image so that the printed image does not come into contact with the contents.

[0003] On the other hand, in the case of front printing, there is no risk of the printed image coming into contact with the contents, so there is no need to laminate the printed image. In other words, front printing is less expensive than reverse printing because no lamination is required.

[0004] When a recording medium on which an image is formed by surface printing is heat-sealed, the heating for heat-sealing is performed from the side on which the image is formed, and therefore various studies have been conducted to improve the heat resistance of that side. For example, Patent Document 1 discloses a printing device that adjusts the film thickness of an ink layer formed on the surface of a substrate within an appropriate range. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-162794 Summary of the Invention [Problem to be solved by the invention]

[0006] However, it has been found that there is room for improvement in the image quality of the recording medium on which an image is formed using the printing device described in Patent Document 1. [Means for solving the problem]

[0007] The present invention is a method for recording on a recording medium, the recording medium having a sealed area that is bonded by heat sealing and a heated area that comes into contact with a heating means for the heat sealing, the sealed area and the heated area being located on the front and back sides of each other on the recording medium, the method comprising: an image forming step of ejecting a colored ink composition from an inkjet head and adhering it to the heated area to form an image; and a protective layer forming step of ejecting a protective composition from the inkjet head and adhering it to the image formed in the heated area to form a protective layer. [Brief explanation of the drawings]

[0008] [Figure 1] 5A to 5C are cross-sectional views showing a process of heat-sealing a recording medium used in the present embodiment. [Figure 2] FIG. 2 is a schematic diagram of a recording apparatus used in the present embodiment. [Figure 3] FIG. 10 is a flowchart illustrating a processing procedure of a protective layer forming step in a control unit. [Figure 4] 1 is a table showing the results of examples. [Figure 5] 1 is a table showing the results of examples. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail with reference to the drawings as necessary, but the present invention is not limited to this, and various modifications are possible without departing from the spirit of the present invention. In the drawings, the same elements are given the same reference numerals, and redundant explanations will be omitted. Furthermore, positional relationships such as up, down, left, and right will be based on the positional relationships shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios of the drawings are not limited to those shown in the drawings.

[0010] 1. Recording device The recording apparatus of this embodiment is used to perform the recording method of this embodiment described below, and is a recording apparatus for recording media having a seal area that is bonded by heat sealing and a heating area that comes into contact with a heating means for the heat sealing, wherein the seal area and the heating area are located on the front and back sides of each other on the recording medium, and the recording apparatus has an inkjet head that ejects a colored ink composition and adheres it to the heated area to form an image, an inkjet head that ejects a protective composition to form a protective layer, and a control unit that controls the ejection of the protective composition by the inkjet head, and the control unit controls the ejection of the protective composition so that the protective composition adheres to the image formed in the heated area.

[0011] Before describing the recording device, the configuration of the recording medium will be described. Fig. 1 shows a cross-sectional view of the process of heat-sealing the recording medium used in this embodiment. Fig. 1 shows an aspect in which a bag-shaped recording medium F is conveyed in the direction of arrow A, and in the process, the recording medium F is heated by heating means 13 to heat-seal the sealed areas 11. In this embodiment, the recording medium F has a sealed area 11 that is bonded by heat sealing and a heated area 12 that comes into contact with the heating means 13 for the heat seal. As shown in Fig. 1, the sealed area 11 and the heated area 12 are located on the front and back of the recording medium F.

[0012] The temperature of the heating means 13 can reach around 200°C, and at such high temperatures, the components of the ink composition that have adhered to the recording surface of the recording medium F on the heated area 12 side may adhere to the heating means 13 and be transferred to the next heat seal area.

[0013] As an example of an inkjet device, a serial printer is shown in a perspective view in Fig. 2. As shown in Fig. 2, the serial printer 20 includes a control unit 210, a conveyance unit 220, and a recording unit 230.

[0014] The control unit 210 can control the overall operation of the serial printer 20. For example, the control unit 210 can control the ejection of the protective composition from the inkjet head. The control unit 210 can also control the ejection of the protective composition so that the protective composition adheres to the image formed in the heated area.

[0015] As described above, in this embodiment, an image is formed by adhering the colored ink composition to the recording surface of the recording medium F on the heated region 12 side. That is, when an image is formed in the heated region 12, the ink coating comes into contact with the heating means 13. Here, the control unit 210 "controls the ejection of the protective composition so that the protective composition adheres to the image formed in the heated region" means that the control unit 210 identifies the position of the heated region 12 on the recording surface of the recording medium F, and when it determines that an image will be formed in the heated region 12 based on the identified position of the heated region 12 and the printing data, controls the ejection of the protective composition from the inkjet head so that the protective composition adheres to the image formed in the heated region 12.

[0016] The conveying unit 220 conveys the recording medium F fed to the serial printer to the recording unit 230, and ejects the recording medium after recording outside the serial printer. Specifically, the conveying unit 220 has a recording medium feed roller, and conveys the fed recording medium F in the sub-scanning direction T2.

[0017] The recording unit 230 also includes an inkjet head 231, a carriage 234 that carries the inkjet head 231 having nozzles that eject an ink composition onto the recording medium F sent from the conveying unit 220, and a carriage moving mechanism 235 that moves the carriage 234 in the main scanning directions S1 and S2 of the recording medium F.

[0018] The inkjet head 231 ejects the colored ink composition and the protective composition. There may be multiple inkjet heads 231, or there may be only one. The inkjet head 231 that ejects the colored ink composition and the inkjet head 231 that ejects the protective composition may be the same or different. The inkjet head 231 that ejects the colored ink composition is also referred to as the first inkjet head 231A, and the inkjet head 231 that ejects the protective composition is also referred to as the second inkjet head 231B. The first inkjet head 231A and the second inkjet head 231B may be the same or different.

[0019] The installation position of the drying mechanism 240 is not particularly limited as long as it is located in a position where it can heat the recording medium F. In the example of Fig. 2, the drying mechanism 240 is installed on the platen 240 at a position facing the inkjet head 231. When the drying mechanism 240 is installed at a position facing the inkjet head 231, it is possible to reliably dry the recording medium F to which the ink composition has adhered.

[0020] Other examples of the drying mechanism 240 include a heating mechanism that heats the recording medium F by contacting the recording medium F with a heat source, a mechanism that irradiates infrared rays or microwaves, which are electromagnetic waves with a maximum wavelength of approximately 2450 MHz, and the like; and a blowing mechanism that blows air onto the recording medium F, such as a dryer mechanism that blows warm air or room temperature air.

[0021] In the case of a serial printer, an inkjet head 231 having a length smaller than the width of the recording medium is provided, and the head moves to perform recording in multiple passes. In a serial printer, the head 231 is mounted on a carriage 234 that moves in a predetermined direction, and the head moves in conjunction with the movement of the carriage to eject the ink composition onto the recording medium F. In this way, recording is performed in two or more passes. The passes are also referred to as main scans.

[0022] Furthermore, while the recording device of this embodiment has been described above with reference to Figure 1 using a serial printer as an example, the recording device of this embodiment may also be a line printer. In a line printer, a line head is fixed and the recording medium is moved in the sub-scanning direction (the longitudinal direction of the recording medium, the transport direction), and ink droplets are ejected from the nozzle openings of the head in conjunction with this movement to record an image on the recording medium. Generally, in a line printer, the head is fixed and does not move, and recording is performed in one pass (single pass), which gives line printers an advantage over serial printers in terms of faster recording speed.

[0023] In this case, the first inkjet head 231A is positioned upstream in the conveyance direction of the recording medium, and the second inkjet head 231B is positioned relatively downstream, so that the first inkjet head 231A forms a background image, and the second inkjet head 231B forms a main image on the background image.

[0024] 2. Recording method The recording method of this embodiment (hereinafter also simply referred to as "recording method") is a method for recording on a recording medium, the recording medium having a sealed area that is bonded by heat sealing and a heated area that comes into contact with a heating means for the heat sealing, the sealed area and the heated area being located on the front and back of each other on the recording medium, and the method has an image forming step of ejecting a colored ink composition from an inkjet head and adhering it to the heated area to form an image, and a protective layer forming step of ejecting a protective composition from an inkjet head and adhering it to the image formed in the heated area to form a protective layer.

[0025] When a recording medium on which an image is formed by surface printing is heated from the side on which the image is formed for heat sealing, if the side on which the image is formed is directly heated, the image tends to peel off due to the heat, resulting in deterioration of image quality. Furthermore, ink from the peeled image tends to transfer to a member to be heat-sealed, contaminating the member. Therefore, various studies have been conducted to impart heat resistance to the side on which the image is formed.

[0026] In order to impart heat resistance to the surface on which an image is formed, in addition to adjusting the film thickness of the ink layer formed on the surface of the substrate within an appropriate range, for example, a heat-resistant protective composition is applied to the image. For example, in the past, after forming an image using a colored ink composition, the entire recording surface was varnished to form a protective layer, and then a heat-sealing process was performed. However, applying varnish to the entire surface is expensive, and the inability to perform the varnishing process within the same recording device also increases costs. Alternatively, applying a protective composition to the entire surface by inkjet printing is also possible instead of varnishing. However, this method delays the drying of the image, which can lead to uneven bleeding due to the mixing of adjacent ink droplets ejected during image formation, resulting in a tendency for image quality to deteriorate.

[0027] In addition, the heat resistance of ink for forming an image is improved by, for example, mixing a heat-resistant component into the ink. This makes it possible to prevent the image from peeling off and to prevent deterioration of image quality even when the surface on which an image has been formed using the ink is heated for heat sealing. However, because the ink contains a heat-resistant component, it tends to have poor color development, resulting in deterioration of image quality.

[0028] Therefore, in the recording method of this embodiment, a protective composition is applied to the heated area of ​​the surface on which an image is formed, which is heated for heat sealing. This makes it possible to suppress image peeling even when the surface on which the image is formed is heated for heat sealing. Furthermore, the area on the image on which the protective composition is applied can be reduced to an extent that image peeling due to heating for heat sealing can be suppressed, and bleeding unevenness can be suppressed in areas on the image other than the heated area. In other words, deterioration of the image quality as a whole can be suppressed.

[0029] Each step of the recording method of this embodiment will be described in detail below.

[0030] 2.1. Heating area identification process First, the recording method of this embodiment may include a heating area specifying step of specifying a heating area based on image data for forming an image. Specifically, in the heating area specifying step, the control unit 210 processes the image data to specify the heating area. Figure 3 is a flow diagram illustrating the processing procedure of the protective layer forming step in the control unit 210.

[0031] After reading the input image data, the control unit 210 identifies a heating area on the image where heating for heat sealing is to be performed in step s101. For example, the control unit 210 identifies the heating area based on the position of an identification mark in the image data. Specifically, if the image has an identification mark, the control unit 210 may recognize the position of the identification mark in the image data as the heating area. Alternatively, if the image has multiple identification marks, the control unit 210 may recognize the area between adjacent identification marks in the image data as the heating area. Note that an identification mark is a mark used for positioning in a printing process or a processing process, such as a photoelectric tube mark or a register mark.

[0032] In step s102, the control unit 210 transmits an execution signal to the conveying unit 220 and the recording unit 230 to form an image based on the input image data, and causes the conveying unit 220 and the recording unit 230 to form the image.

[0033] In step s103, the control unit 210 sends an execution signal to the conveying unit 220 and the recording unit 230 to apply a protective composition to the heating area identified in step s101, causing the conveying unit 220 and the recording unit 230 to form a protective layer.

[0034] 2.2. Image forming process The recording method of this embodiment includes an image forming step of ejecting a colored ink composition from an inkjet head and depositing it on a heated area to form an image. In the image forming step, the area on the recording medium to which the colored ink composition is ejected from the inkjet head and deposited may be any area that includes a heated area, and may be, for example, an area that includes a heated area and a non-heated area that is an area other than the heated area on the side of the recording medium that has the heated area.

[0035] The image forming process may include a white image forming process in which a white ink composition described below is ejected from an inkjet head and deposited on a heated area to form a white image, and a colored image forming process in which, after the white image forming process, a colored ink composition described below is ejected from an inkjet head and deposited on the white image in the heated area to form a colored image. The colored ink composition may contain a white ink composition. That is, the colored image may have a region that is a white image formed by the white ink composition. When the image forming process includes a white image forming process and a colored image forming process, the color of the recording medium is concealed by the white image, resulting in excellent color development of the colored image on the white image, and as a result, a recorded product with excellent image quality tends to be obtained.

[0036] Furthermore, when forming an image, the protective composition and the colored ink composition described below may be simultaneously ejected from an inkjet head to form the image, which can impart abrasion resistance and heat resistance to the image and shorten the time required for image formation.

[0037] 2.3. Pre-drying process The recording method of this embodiment may include a drying step of drying the image after the image forming step and before the protective layer forming step. By including the pre-drying step in the recording method of this embodiment, the image formed in the image forming step becomes easier to dry, and the formation of the protective layer tends to suppress the occurrence of bleeding unevenness.

[0038] When a pre-drying step is performed, the pre-drying step preferably includes an air blowing step of blowing air onto the image or a heating step of heating the image. In the pre-drying step, both the air blowing step and the heating step may be performed, or only one of them may be performed. When both the air blowing step and the heating step are performed in the pre-drying step, both steps may be performed simultaneously, or one step may be performed after the other step is completed.

[0039] The air blowing step may be performed by a hot air heater, a blower without a heating function, etc. The heating step may be performed by a platen heater, a hot air heater, an IR heater, etc.

[0040] The time for performing the pre-drying process is not particularly limited, but for example, the pre-drying process may be performed simultaneously by heating with a platen heater while the image forming process is being performed, and the protective layer forming process may be performed immediately after the image forming process is completed.

[0041] When the pre-drying step includes a heating step, the heating temperature in the heating step is preferably 30 to 75°C, 35 to 70°C, or 40 to 65°C. A higher heating temperature is preferable because it accelerates the drying of the image, but if the heating temperature is too high, the recording medium may shrink, melt, or have other adverse effects on the recording medium. On the other hand, by keeping the heating temperature in the heating step within the above range, it is possible to accelerate the drying of the image while suppressing the occurrence of adverse effects on the recording medium.

[0042] 2.4.Protective layer formation process The recording method of this embodiment includes a protective layer forming step of ejecting a protective composition from an inkjet head and adhering it to an image formed in a heated area to form a protective layer. By forming a protective layer in the heated area where the image has been formed, peeling of the image from the heated area can be suppressed even when the heated area is heated for heat sealing.

[0043] In the protective layer forming step, the protective composition may be applied to the heated area, and the protective composition may not be applied to the image formed in the area other than the heated area. In this case, the protective composition is not applied to the area other than the heated area on the image, so that the occurrence of bleeding unevenness in the area can be suppressed. In other words, the deterioration of the image quality as a whole can be suppressed.

[0044] On the other hand, in the protective layer forming step, the protective layer may be formed in an area other than the heated area on the image. For example, when the protective composition is a composition that forms a transparent, glossy layer after curing, forming the protective layer in that area can impart a glossy appearance to the image.

[0045] However, when forming a protective layer in an area other than the heated area on an image, if the amount of protective composition deposited per unit area is too large, bleeding unevenness may occur in that area, which may deteriorate the image quality of the entire image. From this perspective, it is preferable that the amount of protective composition deposited per unit area M1 in the heated area be greater than the amount of protective composition deposited per unit area M2 in the non-heated area.

[0046] The coating amount M1 is preferably 2.0 mg / inch 2 More than 10.0 mg / inch 2 Less than 2.5 mg / inch 2 More than 9.5mg / inch 2 less than 3.0 mg / inch 2 Over 9.0mg / inch 2 Less than 3.5 mg / inch 2 More than 8.5mg / inch 2 Alternatively, the deposition amount M1 is preferably 1 mg / inch or less. 2 More than 6mg / inch 2 Less than 1.5 mg / inch 2 More than 5.0mg / inch 2 The following is the result.

[0047] The coating amount M2 is preferably 2.0 mg / inch 2Less than 0 mg / inch and 2.0 mg / inch 2 Less than 0 mg or more and 1.8 mg / inch 2 0 mg or more and 1.6 mg / inch or less 2 0 mg or more and 1.4 mg / inch or less 2 0 mg or more and 1.2 mg / inch or less 2 or less, and 0 mg or more and 1.0 mg / inch 2 Alternatively, the deposition amount M2 is preferably 1 mg / inch or less. 2 Less than 0 mg / inch and 1 mg / inch 2 Less than 0 mg or more and 0.8 mg / inch 2 The following is the result.

[0048] In addition, when an image is formed by simultaneously ejecting the protective composition and the colored ink composition from an inkjet head in the image forming process, the amount of the protective composition adhered in the image forming process is not included in the amounts of adhesion M1 and M2 in the protective layer forming process.

[0049] 2.5. Post-drying process The recording method of this embodiment may include a post-drying step for drying the image and protective layer formed on the recording medium after the protective layer forming step. The post-drying step may be performed by the same method as the pre-drying step described above. The time for performing the post-drying step is not particularly limited as long as it can sufficiently dry the image and protective layer formed on the recording medium, but it may be performed for, for example, 1 minute. Furthermore, if the post-drying step includes a heating step, the heating temperature in the post-heating step is not particularly limited, but is, for example, 30 to 75°C.

[0050] 3. Ink composition The recording method of this embodiment uses a colored ink composition and a protective composition. Each of the ink compositions will be described in detail below.

[0051] 3.1. Colored ink composition The colored ink composition of this embodiment is an ink composition used in an image forming process. The colored ink composition will be described in detail below.

[0052] 3.1.1. Coloring agents The colored ink composition of this embodiment preferably contains a colorant. Examples of colorants include dyes and pigments, and it is preferable to use a pigment. Examples of pigments include, but are not limited to, inorganic pigments and organic pigments. Examples of inorganic pigments include, but are not limited to, carbon blacks such as furnace black, lamp black, acetylene black, and channel black, iron oxide, and titanium oxide. Examples of organic pigments include azo pigments such as insoluble azo pigments, condensed azo pigments, azo lakes, and chelate azo pigments, phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments, polycyclic pigments such as dye chelates, dye lakes, nitro pigments, nitroso pigments, aniline black, and daylight fluorescent pigments. The colorant may be used alone or in combination of two or more.

[0053] Examples of colored ink compositions include white ink compositions and non-white ink compositions. In this embodiment, the white ink composition is an ink composition having a whiteness of 70% to 100% as measured in accordance with JIS Z8715:1999. The white ink composition contains a white coloring agent. The non-white ink composition is a colored ink composition other than a white ink composition. The non-white ink composition contains a coloring agent other than a white coloring agent, but may contain a white coloring agent.

[0054] The carbon black is not particularly limited, and examples thereof include No. 2300, No. 900, MCF88, No. 33, No. 40, No. 45, No. 52, MA7, MA8, MA100, No. 2200B, etc. (all manufactured by Mitsubishi Chemical Corporation), Raven 5750, Raven 5250, Raven 5000, Raven 3500, Raven 1255, Raven 700, etc. (all manufactured by Carbon Columbia), Rega1 400R, Rega1 330R, Rega1 660R, Mogul L, Monarch 700, Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400, etc. (manufactured by Cabot Corporation). Examples of such inks include Color Black FW1, Color Black FW2, Color Black FW2V, Color Black FW18, Color Black FW200, Color Black S150, Color Black S160, Color Black S170, Printex 35, Printex U, Printex V, Printex 140U, Special Black 6, Special Black 5, Special Black 4A, and Special Black 4 (all manufactured by Degussa).

[0055] The white pigment is not particularly limited, but examples thereof include CI Pigment White 6, 18, and 21, and titanium oxides such as titanium dioxide.

[0056] The yellow pigment is not particularly limited, but examples thereof include CI Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 16, 17, 24, 34, 35, 37, 53, 55, 65, 73, 74, 75, 81, 83, 93, 94, 95, 97, 98, 99, 108, 109, 110, 113, 114, 117, 120, 124, 128, 129, 133, 138, 139, 147, 151, 153, 154, 155, 167, 172, and 180.

[0057] The magenta pigment is not particularly limited, and examples thereof include CI Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 40, 41, 42, 48(Ca), 48(Mn), 57(Ca), 57:1, 88, 112, 114, 122, 123, 144, 146, 149, 150, 166, 168, 170, 171, 175, 176, 177, 178, 179, 184, 185, 187, 202, 209, 219, 224, and 245, and CI Pigment Violet. Examples include 19, 23, 32, 33, 36, 38, 43, and 50.

[0058] Examples of cyan pigments include, but are not limited to, CI Pigment Blue 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:34, 15:4, 16, 18, 22, 25, 60, 65, and 66, and CI Vat Blue 4 and 60.

[0059] Furthermore, pigments other than magenta, cyan, and yellow are not particularly limited, but examples thereof include CI Pigment Green 7, 10, CI Pigment Brown 3, 5, 25, 26, and CI Pigment Orange 1, 2, 5, 7, 13, 14, 15, 16, 24, 34, 36, 38, 40, 43, and 63.

[0060] The content of the coloring material is preferably 1.0 to 20.0% by mass, and more preferably 2.0 to 15.0% by mass, relative to the total amount of the colored ink composition.

[0061] Dispersants The colored ink composition of this embodiment may contain a dispersant for dispersing the pigment. The dispersant for dispersing the pigment is not particularly limited, and examples thereof include those primarily composed of one or more of polyoxyalkylene polyalkylene polyamines, vinyl polymers and copolymers, acrylic polymers and copolymers, polyesters, polyamides, polyimides, polyurethanes, amino polymers, silicon-containing polymers, sulfur-containing polymers, fluorine-containing polymers, styrene-acrylic resins, and epoxy resins. Commercially available dispersants include the Ajisper series manufactured by Ajinomoto Fine-Techno Co., Ltd., the Solsperse series available from Avecia Co. (e.g., Solsperse 36000 (acid value 45) and Solsperse 32000 (amine value 35)), the Disperbyk series manufactured by BYK Chemie (e.g., DISPERBYK 168 and 180), and the Disparlon series manufactured by Kusumoto Chemicals Co., Ltd. The dispersants may be used alone or in combination of two or more.

[0062] The content of the dispersant relative to the total amount of the colored ink composition is not particularly limited, but is, for example, 0.1 to 3.0% by mass.

[0063] 3.1.2. Fixing resin The colored ink composition of this embodiment may contain a fixing resin. By containing a fixing resin, the abrasion resistance of the recorded matter tends to be improved.

[0064] The fixing resin may be a resin particle or a resin emulsion, in which the resin particles are contained in the ink in a dispersed form, or a resin particle dissolved in the solvent component of the ink in a dissolved form.

[0065] The fixing resin is not particularly limited, but examples thereof include resin particles made of urethane resin, acrylic resin (including styrene-acrylic resin), fluorene resin, polyolefin resin, rosin-modified resin, terpene resin, polyester resin, polyamide resin, epoxy resin, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer, ethylene vinyl acetate resin, etc. The fixing resin may be used alone or in combination of two or more.

[0066] Among these, urethane resins, acrylic resins, and polyolefin resins are preferred. These resin particles are often handled in the form of an emulsion, but may also be in the form of a powder.

[0067] Urethane resin is a general term for resins having urethane bonds. In addition to urethane bonds, the urethane resin may be a polyether urethane resin containing ether bonds in the main chain, a polyester urethane resin containing ester bonds in the main chain, or a polycarbonate urethane resin containing carbonate bonds in the main chain.

[0068] Acrylic resin is a general term for polymers obtained by polymerizing at least an acrylic monomer such as (meth)acrylic acid or a (meth)acrylic acid ester as one component. Examples include resins obtained from acrylic monomers and copolymers of acrylic monomers with other monomers. Examples include acrylic-vinyl resins, which are copolymers of acrylic monomers and vinyl monomers. Another example of a vinyl monomer is styrene. Other usable acrylic monomers include acrylamide and acrylonitrile.

[0069] Among these, styrene-acrylic resins are preferred. Examples of styrene-acrylic resins include, but are not limited to, styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, styrene-methacrylic acid-acrylic acid ester copolymers, styrene-α-methylstyrene-acrylic acid copolymers, and styrene-α-methylstyrene-acrylic acid-acrylic acid ester copolymers. Use of such resins tends to further improve the image quality and abrasion resistance of the resulting recorded matter.

[0070] The polyolefin resin has an olefin such as ethylene, propylene, or butylene in its structural skeleton, and any known polyolefin resin can be appropriately selected and used.

[0071] The glass transition temperature Tg of the fixing resin is preferably 40° C. or higher, 40 to 180° C., 45 to 150° C., or 50 to 120° C. The Tg of the fixing resin can be adjusted by adjusting the type and composition of the resin and the degree of polymerization. For example, the Tg of the resin can be increased by increasing the degree of polymerization of the resin.

[0072] The content of the fixing resin is preferably 0.1 to 15.0% by mass, 0.5 to 10.0% by mass, or 1.0 to 7.5% by mass relative to the total amount of the colored ink composition.

[0073] Wax The colored ink composition of this embodiment may contain a wax. The wax is not particularly limited, but examples include plant- or animal-based waxes such as carnauba wax, candelilla wax, beeswax, rice wax, and lanolin; mineral waxes such as montan wax and ozokerite; so-called petroleum-based waxes such as paraffin wax; synthetic waxes such as carbon wax, Hoechst wax, polyolefin wax, polyethylene wax, silicone wax, and stearic acid amide; and natural or synthetic wax emulsions or blended waxes such as α-olefin-maleic anhydride copolymers. The wax may be used alone or in combination of two or more types.

[0074] The content of the wax is preferably 0.1 to 5.0% by mass, and more preferably 0.5 to 2.5% by mass, relative to the total amount of the colored ink composition.

[0075] 3.1.4. Organic Solvents The colored ink composition of this embodiment may contain an organic solvent. The organic solvent is not particularly limited, but examples thereof include monohydric alcohols, polyols, and glycol ethers. The organic solvent may be used alone or in combination of two or more.

[0076] The monohydric alcohols are not particularly limited, but examples thereof include methanol, ethanol, 1-propanol, isopropanol, 1-butanol, 2-butanol, isobutanol, and 2-methyl-2-propanol.

[0077] The polyols are not particularly limited, but examples thereof include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and glycerin.

[0078] The glycol ethers are not particularly limited, but examples thereof include triethylene glycol monomethyl ether, triethylene glycol dimethyl ether, triethylene glycol monobutyl ether, diethylene glycol monobutyl ether, and dipropylene glycol monopropyl ether.

[0079] The content of the organic solvent relative to the total amount of the colored ink composition is not particularly limited, but is, for example, 15.0 to 35.0 mass %, 17.5 to 32.5 mass %, or 20.0 to 30.0 mass %.

[0080] Surfactants The colored ink composition of this embodiment may contain a surfactant. Examples of surfactants include, but are not limited to, acetylene glycol surfactants, fluorine-based surfactants, and silicone-based surfactants. These surfactants may be used alone or in combination of two or more. Examples of silicone-based surfactants include, but are not limited to, BYK-UV3500, BYK350, and BYK-348 (trade names manufactured by BYK Japan). Examples of acetylene glycol-based surfactants include Olfine E1010 (trade name manufactured by Nissin Chemical Industry Co., Ltd.). Examples of fluorine-based surfactants include, but are not limited to, FS-300 (manufactured by DuPont) and Fluorad-FC4430 (manufactured by Sumitomo 3M Limited).

[0081] The content of the surfactant relative to the total amount of the colored ink composition is not particularly limited, but may be, for example, 0.1 to 2.0% by mass.

[0082] 3.1.6.Water The water contained in the colored ink composition of this embodiment is not particularly limited, but examples thereof include ion-exchanged water, ultrafiltered water, reverse osmosis water, distilled water, and pure water.

[0083] The content of water is preferably 50 to 80% by mass, and more preferably 55 to 75% by mass, relative to the total amount of the colored ink composition.

[0084] 3.2. Protective composition The protective composition of this embodiment is a composition used in the protective layer forming step. The protective composition will be described in detail below.

[0085] 3.2.1. Coloring agents The protective composition of this embodiment does not contain or substantially does not contain a colorant. In this embodiment, the term "substantially free of colorant" is not particularly limited, but may refer to, for example, a colorant content of 0.50% by mass or less, 0.25% by mass or less, 0.10% by mass or less, 0.05% by mass or less, 0.01% by mass or less, 0.001 to 0.500% by mass, 0.001 to 0.250% by mass, 0.001 to 0.100% by mass, 0.001 to 0.050% by mass, or 0.001 to 0.010% by mass, relative to the total amount of ink. When the protective composition is substantially free of colorant, examples of the colorant include the colorants exemplified in the colored ink composition.

[0086] 3.2.2. Fixing resin The protective composition of this embodiment may contain a fixing resin. The inclusion of a fixing resin tends to improve the abrasion resistance of the recorded material. The type and content of the fixing resin contained in the protective composition are the same as those described for the colored ink composition.

[0087] The glass transition temperature Tg of the fixing resin is preferably 40° C. or higher, 40 to 180° C., 45 to 150° C., 50 to 120° C., or 60 to 100° C. Furthermore, the fixing resin is preferably an acrylic resin.

[0088] Wax The protective composition of this embodiment may contain a wax. The type and content of the wax contained in the protective composition are the same as those described for the colored ink composition.

[0089] 3.2.4. Organic Solvents The protective composition of this embodiment may contain an organic solvent. The type and content of the organic solvent contained in the protective composition are the same as those described for the colored ink composition.

[0090] Surfactants The protective composition of this embodiment may contain a surfactant. The type and content of the surfactant contained in the protective composition are the same as those described for the colored ink composition.

[0091] 3.2.6.Water The water contained in the protective composition of the present embodiment is not particularly limited, but examples thereof include ion-exchanged water, ultrafiltered water, reverse osmosis water, distilled water, and pure water.

[0092] The water content is preferably 50 to 80% by mass, and more preferably 55 to 75% by mass, based on the total amount of the protective composition.

[0093] 4. Method for producing ink composition The method for producing the ink composition of this embodiment is not particularly limited, but may involve, for example, mixing the above-described components. Alternatively, a colorant dispersion liquid may be prepared by dispersing a colorant and a dispersant in a solvent, and the resulting colorant dispersion liquid may be mixed with the other above-described components.

[0094] 5. Recording Media The recording medium used for recording with the ink composition of this embodiment is not particularly limited, but examples thereof include absorbent recording media, low absorbent recording media, and non-absorbent recording media. Of these, non-absorbent recording media are preferred.

[0095] Examples of absorbent recording media include, but are not limited to, plain paper such as electrophotographic paper that has high ink permeability, inkjet paper (paper specifically for inkjet printers that has an ink absorbing layer made of silica particles or alumina particles, or an ink absorbing layer made of a hydrophilic polymer such as polyvinyl alcohol (PVA) or polyvinylpyrrolidone (PVP)), kraft paper used in the packaging field, and paper coated with a barrier coating agent.

[0096] The low-absorbency recording medium is not particularly limited, but examples thereof include art paper, coated paper, cast paper, and one-side glossy paper that are used in general offset printing and have relatively low ink permeability.

[0097] Non-absorbent recording media are not particularly limited, but examples include plastic films such as polyvinyl chloride, polyethylene, polypropylene, biaxially oriented polypropylene, polyethylene terephthalate (PET), biaxially oriented polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, etc.; recording media in which a plastic film such as polyvinyl chloride, polyethylene, polypropylene, polyethylene terephthalate (PET), polycarbonate, polystyrene, polyurethane, etc. is adhered (coated) to a paper substrate; and films that are heat-sealable to the above recording media, such as films laminated with uniaxially oriented polypropylene (CPP) or very low density polyethylene (LLDPE).

[0098] The recording medium of this embodiment has a sealed area that is bonded by heat sealing and a heated area that comes into contact with a heating means for heat sealing. Here, the sealed area and the heated area are located on the front and back sides of the recording medium. That is, the heating means comes into contact with the heated area, and the sealed area located on the back side of the heated area is bonded to another member, such as a recording medium. Furthermore, the area other than the heated area on the side of the recording medium of this embodiment on which an image is formed is also referred to as a non-heated area.

[0099] Since the heated area is only a small portion of the entire image, even if the protective composition is applied to the image formed in the heated area, the image quality of the entire image will not be deteriorated. Furthermore, the image formed in the heated area may be an image without a design, such as a solid image, and the image formed in the area other than the heated area may be an image with the desired design. This can further suppress the effects of applying the protective composition to the image formed in the heated area. [Example]

[0100] The present invention will be described in more detail below using examples and comparative examples. The present invention is not limited to the following examples. Unless otherwise specified, the experiments in the examples and comparative examples were carried out at room temperature (25°C) and 1 atmosphere.

[0101] 1. Preparation of colored ink composition and protective composition The colored ink composition and protective composition used in each example were obtained by placing each component in a stainless steel mixing tank, mixing and stirring at room temperature, and removing impurities and foreign matter as needed by filtration, etc., so as to obtain the composition shown in Figure 4. The numerical values ​​for each component shown in each example in the figure represent % by mass unless otherwise specified. The % by mass of the colorant, fixing resin, and wax represent the solids concentration.

[0102] The abbreviations in Figure 4 represent the following compounds and products: PB15:3: Pigment Blue 15:3 PW6: Pigment White 6 Resin 1: Styrene-acrylic resin emulsion, Tg=65℃ Resin 2: Styrene-acrylic resin emulsion, Tg=90℃ BYK348: BYK surfactant (product name)

[0103] 2. Recording method [Example 1] The recording medium used was a laminate film made by laminating a 30 μm thick plastic film, FOS-BT (product name, manufactured by Futamura Chemical Co., Ltd.), and a 30 μm thick CPP (FHK2, manufactured by Futamura Chemical Co., Ltd.). The recording device used was a modified Seiko Epson L-4733AW. The recording device had a control unit, which was capable of performing a heating area identification process based on image data for forming an image, determining whether an image is formed in the heating area identified in the heating area identification process, and applying a protective composition to the image formed in the heating area to form a protective layer.

[0104] The recording medium was set, and information about the photocell marks and image data were prepared, and recording was performed along with processing in the control unit of the recording device. The photocell marks identified the heated area, and the image data formed an image in that heated area.

[0105] First, a white ink composition, which is a colored ink composition, is applied to a recording medium at a density of 13.5 mg / inch 2 Next, a cyan ink composition, which is a colored ink composition, was printed on the recording medium at a deposition amount of 6 mg / inch to form a white image. 2 A colored image was formed by printing with a deposition amount of 2.5 mg / inch. The white image and the colored image were printed to a resolution of 720 x 720 dpi. Next, the protective composition was applied to the heated area on the image that was to be heated for heat sealing at a deposition amount of 2.5 mg / inch. 2 It was attached with.

[0106] When forming the white image and the colored image, the platen temperature was set to 45°C to dry the white image and the colored image. After the formation of the white image and the colored image was completed, a protective layer was formed. When the formation of the protective layer began, the white image and the colored image were not completely dry. After the formation of the protective layer was completed, the recording medium on which the protective layer had been formed was heated at 75°C to completely dry the white image, the colored image, and the protective layer. In this way, the recorded matter of Example 1 was obtained.

[0107] [Examples 2 to 6, Comparative Example 1] Printing was performed in the same manner as in Example 1, except that printing was performed under the printing conditions shown in Figures 4 and 5, to obtain recorded materials of Examples 2 to 6 and Comparative Example 1. When applying the protective composition to the non-heated area, the protective composition was applied to the non-heated area in the same manner as the method for applying the protective composition to the heated area, so as to achieve the amount of application shown in Figure 5. The non-heated area is the area other than the heated area on the side of the recording medium that has the heated area.

[0108] 3. Evaluation Method 3.1.Heat seal resistance The heated area of ​​the recorded matter obtained as described above was heated from the recording surface side using a pressure roller at 230°C and a pressure of 0.35 MPa for 30 seconds. After cooling, the image peeling in the heated area was visually observed and evaluated based on the following evaluation criteria. [Evaluation criteria] A: No peeling or other issues were observed in the image in the heated area after heat sealing. B: Peeling of the image is observed in less than 5% of the heated area after heat sealing. C: Peeling of the image is observed in 5% or more of the heated area after heat sealing.

[0109] 3.2.Image quality of non-heated areas The unheated area was visually observed and evaluated based on the following evaluation criteria. [Evaluation criteria] A: There is no unevenness in the density of the non-heated area, and there is no ink accumulation on the edge of the non-heated area. B: There is some unevenness in the density of the non-heated area or some ink accumulation at the edge of the non-heated area. C: There is obvious unevenness in the shading in the unheated area or obvious ink pooling at the edge of the unheated area. [Explanation of symbols]

[0110] 11...sealing area, 12...heating area, 13...heating means, 20...serial printer, 210...controller, 220...conveyor, 230...recording unit, 231...inkjet head, 234...carriage, 235...carriage moving mechanism, 240...drying mechanism, F...recording medium, S1, S2...main scanning direction, T2...sub-scanning direction

Claims

1. A recording method for recording on a recording medium, the recording medium has a sealing area that is bonded by heat sealing and a heating area that comes into contact with a heating means for the heat sealing, the sealing area and the heating area are positioned on the front and back sides of the recording medium, an image forming step of ejecting a colored ink composition from an inkjet head and depositing it on the heated area to form an image; a protective layer forming step of ejecting a protective composition from an inkjet head and adhering it to the image formed in the heated region to form a protective layer. Recording method.

2. the recording medium has a non-heated area other than the heated area, In the protective layer forming step, the amount of the protective composition adhered per unit area in the heating region M 1 is the amount of the protective composition adhered per unit area in the non-heated region M 2 More than The recording method according to claim 1 .

3. Said adhesion amount M 1 is 1 mg / inch 2 6mg / inch or more 2 is as follows: Said adhesion amount M 2 is 1 mg / inch 2 is less than The recording method according to claim 2 .

4. In the image forming step, the color ink composition is ejected from the inkjet head and deposited on an area other than the heated area on the side of the recording medium having the heated area, thereby forming an image; The protective composition is not applied to the image formed in the area other than the heated area. The recording method according to claim 2 .

5. a heating area specifying step of specifying the heating area based on image data for forming the image; The recording method according to claim 1 .

6. In the heating region specifying step, an identification mark is specified based on image data for forming the image, and the heating region is specified based on the specified identification mark. The recording method according to claim 5 .

7. The colored ink composition is a water-based ink composition containing a colorant. The recording method according to claim 1 .

8. The protective composition is an aqueous composition containing a fixing resin. The recording method according to claim 1 .

9. The glass transition temperature Tg of the fixing resin is 50 to 120°C. The recording method according to claim 8.

10. The fixing resin includes an acrylic resin. The recording method according to claim 8.

11. A recording apparatus for performing the recording method according to any one of claims 1 to 10, A recording device for a recording medium having a sealing area to be bonded by heat sealing and a heating area to be contacted by a heating means for the heat sealing, the sealing area and the heating area are located on the front and back sides of the recording medium, an inkjet head that ejects the colored ink composition and deposits it on the heated area to form an image; the inkjet head that ejects the protective composition to form a protective layer; a control unit that controls the ejection of the protective composition from the inkjet head, the control unit controls the ejection of the protective composition so that the protective composition adheres to the image formed in the heating region. Recording device.

Images