WO2013150949A1 - Image protection method, image formation method, printed material, and image protection composition - Google Patents

Description

Image protection method, image forming apparatus, printed material, image protection composition

The present invention relates to an image protection method, an image forming apparatus, a printed material, and an image protection composition.

Patent Document 1 describes a movie film having an antihalation undercoat, a silver halide emulsion layer, an antistatic layer, a protective overcoat, and a topcoat containing gelatin-coated latex particles.

Patent Document 2 discloses a building board comprising a step of performing inkjet coating with UV ink, a step of curing UV ink with ultraviolet rays, and a step of performing clear coating on a surface subjected to inkjet coating. A manufacturing method is described.

JP 2000-10240 A (published January 14, 2000) JP 2010-167334 A (published January 14, 2000)

In the method described in Patent Document 2, since the UV ink is cured, there is no possibility that the clear coating ink erodes the UV ink.

However, ink for ink-jet coating is limited to UV ink. For example, when an image is formed with a solvent ink in which a colorant and a binder resin are dissolved in a solvent or monomer, and clear coating is performed with UV ink or the like, the solvent ink is dissolved in the solvent of the UV ink or the solvent ink after coating There is a problem of swelling. In this case, the UV ink for clear coating needs to be cured immediately after landing in order to suppress erosion to the solvent ink as much as possible, and the surface cannot be smoothed (leveled). That is, if the UV ink is cured immediately after landing, the ink surface is cured without being smoothed, so that the graininess of the landed ink dots remains and the printing surface does not become smooth.

The present invention has been made in view of such problems, and it is an object of the present invention to provide a method of protecting an image by suppressing the erosion of the image by a protective layer, which can smooth the printing surface.

The image protection method according to the present invention includes a protective layer forming step of forming a protective layer for protecting the image layer on the image layer, and the protective layer includes water or a hydrophilic organic solvent and a resin, The resin is formed by an inkjet method using an aqueous latex ink that is emulsified or suspended in the water or a hydrophilic organic solvent.

An aqueous latex ink for forming a protective layer containing water or a hydrophilic organic solvent and a resin, in which the resin is emulsified or suspended in the water or the hydrophilic organic solvent, is an image formed of any ink. Even a layer can be applied without flipping. Further, since the solvent evaporates to form a resin layer and is cured, the resin layer is leveled before the solvent evaporates, and the printing surface can be smoothed. Furthermore, since it is a water-based ink, even if it is applied on the image layer as compared with the volatile organic solvent used in the solvent-based ink, the erosion of the image layer can be suppressed. More specifically, the image layer is not eroded by the solvent until the solvent in which the resin layer is leveled evaporates, and the surface of the aqueous latex ink is smoothed. It is possible to secure time for leveling the ink surface during this period. That is, it is not necessary to cure the aqueous latex ink immediately after landing, and it is possible to secure a time until the granular feeling of the landed ink dots disappears. Therefore, the printing surface can be smoothed, and the image can be protected by suppressing the erosion of the image by the protective layer.

Also, a large-sized device is not necessary as compared with the case where a protective layer is formed using a laminator. In addition, there is no generation of soot due to the laminator. In addition, since the protective layer can be coated while the colored layer is printed, workability can be improved.

Also, the use of water-based latex ink improves wettability and allows printing without being repelled on the image layer.

In the image protection method according to the present invention, it is more preferable that the image layer is formed of an aqueous latex ink using an inkjet method.

Water-based latex ink is no longer eroded by water-based latex ink once dried. Therefore, the aqueous latex ink of the image layer is not eroded by the aqueous latex ink of the protective layer. Therefore, since the colored layer is not eroded while the solvent is dried, the protective layer can be leveled and the glossiness is improved.

In the image protection method according to the present invention, it is more preferable to use a piezo method as the ink jet method.

Inkjet methods include thermal and piezo methods. In the case of a thermal head, bubbles are generated at a high temperature due to its ejection principle, and ink is likely to scatter around the head when the ink bumps. Here, in the case of a type that does not re-dissolve with the same ink once dried as an aqueous latex ink, the ink film scattered and adhered to the periphery of the nozzle gradually reaches the inside of the nozzle opening, and finally There is a risk of closing the nozzle. Therefore, in order to use the aqueous latex ink for the thermal ink jet, it is necessary to add a solvent having poor drying property, which may cause bleeding. On the other hand, the piezo method has no problem due to such a thermal method, and the ink hardly scatters around the head, so that a solvent having good drying property can be used.

In addition, from the viewpoint of further suppressing re-dissolution of the ink, the resin in the aqueous latex ink preferably has a high molecular weight. However, if the piezo method is used, the aqueous latex ink composed of the resin having a high molecular weight is suitably ejected. be able to.

Further, the image protection method according to the present invention includes a protective layer forming step of forming a protective layer for protecting the image layer on the image layer, and the image layer includes a thermoplastic resin having a lipophilic group. The protective layer is formed of an aqueous ink in which the main component of the solvent is water or a hydrophilic organic solvent.

The water-based ink does not erode the image layer formed with the ink containing the thermoplastic resin having a lipophilic group as a binder. Therefore, it is not necessary to evaporate the solvent in the water-based ink in a short time, and it is possible to secure a time until the granular feeling of the ink dots of the landed water-based ink disappears. Therefore, the printing surface can be smoothed and the image can be protected without the protective layer eroding the image.

In the present invention, when the protective layer is formed by the ink jet method, water-based ink is used as the upper layer in order to prevent the erosion of the lower image layer by the upper protective layer while ensuring the gloss of the surface. The form using the above-described aqueous latex ink is the same in that the aqueous ink is used as a protective layer for securing gloss. Here, if UV ink is used to cure immediately after landing, erosion of the lower image layer can be suppressed, but gloss cannot be secured. By using water-based ink as the upper protective layer, erosion of the lower image layer can be suppressed and gloss can be satisfied.

In the image protection method according to the present invention, the aqueous latex ink is more preferable.

Since the aqueous latex ink forms a resin layer and cures, even when applied on an image layer formed of an ink containing a thermoplastic resin having a lipophilic group as a binder, the erosion of the image layer is further suppressed. be able to. Therefore, it is possible to secure a longer time for smoothing the surface of the aqueous latex ink and a longer time required for air bubbles mixed in the aqueous latex ink to escape from the surface. That is, it is not necessary to cure the aqueous latex ink in a short time, and it is possible to secure a longer time until the granular feeling of the landed ink dots disappears. Therefore, the printing surface can be smoothed and the image layer can be densified, and the image can be effectively protected by further suppressing the erosion of the image by the protective layer.

In the image protection method according to the present invention, it is more preferable that the image layer is formed of an aqueous latex ink using an inkjet method.

By forming both the protective layer and the image layer with the aqueous latex ink, the adhesive strength between them is improved.

In the image protection method according to the present invention, it is more preferable that the protective layer contains an ultraviolet absorber.

Protect images from ultraviolet rays and near ultraviolet rays.

An image forming apparatus according to the present invention includes an image ink discharge portion that discharges ink for forming an image layer, and protective ink for forming a protective layer for protecting the image layer on the image layer. A protective ink discharge portion for discharging, an image ink discharge portion control means for controlling the image ink discharge portion to discharge ink based on image information indicating an image for forming the image layer, and the protection Protective ink discharge unit control means for controlling the protective ink discharge unit to discharge ink onto the image layer so as to form the protective layer.

The image protection method according to the present invention can be carried out, and a printed matter that protects the image protected by the image protection method can be produced.

In the printed material according to the present invention, an image layer is provided on a recording medium, and a protective layer for protecting the image layer is provided on the image layer. Is formed.

Since the image is protected by the image protection method according to the present invention, the image is not eroded by the solvent of the protective layer and the surface is smooth.

The image protection composition according to the present invention contains water or a hydrophilic organic solvent and a resin, and the resin is emulsified or suspended in the water or the hydrophilic organic solvent.

Since it can be used to protect an image by the image protection method according to the present invention, it is possible to provide a printed material in which the image is not eroded by the solvent of the protective layer and the surface is smooth.

According to the present invention, the printing surface can be smoothed, and the protective layer can protect the image without eroding the image.

1 is a diagram schematically showing a configuration of an ink jet recording apparatus (image forming apparatus) 100 that is an embodiment of an image forming apparatus according to the present invention. 2 is a diagram illustrating an example of an arrangement of heads included in the inkjet recording apparatus 100. FIG. 6 is a diagram illustrating another example of an arrangement example of heads included in the inkjet recording apparatus 100. FIG.

<Image protection method>
The image protection method according to the present invention includes a protective layer forming step of forming a protective layer for protecting the image layer on the image layer, and the protective layer is formed of an aqueous latex ink using an inkjet method. It is a thing.

Further, the image protection method according to the present invention includes a protective layer forming step of forming a protective layer for protecting the image layer on the image layer, and the image layer includes a thermoplastic resin having a lipophilic group as a binder. The protective layer may be formed of an aqueous ink whose main component is water or a hydrophilic organic solvent.

In any method, the ink for forming the protective layer (protective ink) is an ink that does not dissolve the ink that has been cured to form the image layer. Therefore, it is not necessary to cure the protective layer in a short time, and it is possible to secure a time until the granular feeling of the ink dots of the landed water-based ink disappears. Therefore, the printing surface can be smoothed and the image can be protected without the protective layer eroding the image.

(Image layer)
What is necessary is just to form an image layer by drawing a desired image with the ink which forms an image on a desired base material. An image is formed by drawing with the ink and drying and curing.

Since various materials such as paper and fabric can be adopted as the substrate, a desired type of substrate may be selected.

As the ink for forming the image layer, when the protective layer is formed with an aqueous ink other than the aqueous latex ink, the ink may be formed with an ink containing a thermoplastic resin having a lipophilic group as a binder. If the ink contains a thermoplastic resin having a lipophilic group as a binder, erosion due to water-based ink can be suppressed.

Examples of the ink containing a thermoplastic resin having a lipophilic group as a binder include a solvent ink which is an ink obtained by dissolving a thermoplastic resin having a lipophilic group in a solvent. Examples of the thermoplastic resin having a lipophilic group include vinyl acetate (copolymer of vinyl chloride and vinyl acetate). If the protective layer is formed of UV ink, vinyl chloride is dissolved depending on the UV ink monomer, so it must be cured immediately after the UV ink has landed. Since the formation is insufficient, the graininess remains. However, in the present invention, when the image layer is formed with an ink containing a thermoplastic resin having a lipophilic group such as vinyl chloride as a binder, the protective layer is formed with an aqueous ink. Does not dissolve or swell. Therefore, it is not necessary to dry the water-based ink and evaporate the solvent in a short time after the water-based ink is discharged, and a time until smoothing can be secured.

Further, as another example of the ink containing a thermoplastic resin having a lipophilic group as a binder, an aqueous latex ink can be mentioned. As will be described later, it is more preferable to form the image layer and the protective layer with an aqueous latex ink because the adhesive strength between the two layers is improved.

When the protective layer is formed with aqueous latex ink, the image layer may be formed with any ink. However, it is more preferable to form both the protective layer and the image layer with an aqueous latex ink. By forming both the protective layer and the image layer with the aqueous latex ink, the properties of the protective layer and the image layer can be made closer, and the adhesive strength between them can be improved. Therefore, it is more preferable that the aqueous latex ink for forming the protective layer and the image layer is the same resin and solvent ink.

[Water-based latex ink]
In this specification, the “aqueous latex ink” refers to an ink containing water or a hydrophilic organic solvent and a resin, and the resin is emulsified or suspended in the water or the hydrophilic organic solvent. In addition to water or a hydrophilic organic solvent, a non-hydrophilic organic solvent having an affinity for the hydrophilic organic solvent may be contained.

In the case of an aqueous latex ink in which the resin is emulsion or suspended in water, it can be said that an aqueous emulsion or aqueous suspension is formed by the resin.

Examples of resins include water-soluble vinyl resins, acrylic resins, alkyd resins, polyester resins, polyurethane resins, silicon resins, fluorine resins, epoxy resins, phenoxy resins, polyolefin resins, etc. And modified resins thereof. Among these, more preferred are acrylic resins, water-soluble polyurethane resins, water-soluble polyester resins, and water-soluble acrylic resins, and particularly preferred are acrylic resins.

The resin contained in the aqueous latex ink can be used alone or in combination of two or more. The blending amount of the resin can be arbitrarily determined depending on the kind of the resin to be used. For example, it is 1% by weight or more with respect to the total amount of the aqueous latex ink, more preferably 2% by weight or more and 20% by weight It is below, and it is more preferable that it is 10 mass% or less.

In the present invention, when the aqueous latex ink is used for protecting an image, a colorant may be added as necessary. For example, the image can be decorated by coating the entire image with a light-colored protective layer.

Water-based latex ink can be cured by drying or applying heat. However, when the aqueous latex ink is used as the protective ink, it is possible to suppress erosion of the image layer formed of any ink. Therefore, in the image protection method according to the present invention, by using the aqueous latex ink, it is possible to secure a longer smoothing time and obtain a printed matter with a smoother surface.

The aqueous latex ink may further contain an emulsifier for emulsifying or suspending the resin.

In the water-based latex ink, the water or the hydrophilic organic solvent may contain another resin dissolved in water or the hydrophilic organic solvent in addition to the emulsion or suspended resin. Another resin can be dissolved in water or a hydrophilic organic solvent to adjust the viscosity of the ink. In addition, when moisture dries by drying, when another film is formed into a film by bonding between emulsions or suspended resins, the other resin is used as a binder to further strengthen the emulsions or suspended resins. It may have a function of combining.

[Water-based ink]
When the image layer is formed using an ink containing a thermoplastic resin having a lipophilic group as a binder, the protective layer can be used as long as it is an aqueous ink as well as the above-described aqueous latex ink. A water-based ink is an ink in which the main component of the solvent is water or a hydrophilic organic solvent. Here, the “main component” is intended to mean the most contained solvent. For example, that the main component of the solvent is water means that water is the largest among the substances contained as the solvent. However, water-based latex ink is more preferable among water-based inks. Since erosion to the image layer can be further suppressed, a printed matter with a smoother surface can be provided.

The water-based ink may also contain a colorant as necessary, similarly to the water-based latex ink described above. Not only a function as a coating for protecting an image but also a function of decorating can be provided.

[Ultraviolet absorber]
More preferably, the protective layer contains an ultraviolet absorber. This is because the image can be protected from ultraviolet rays and near ultraviolet rays. The method for including the ultraviolet absorber in the protective layer is not particularly limited, and for example, the protective ink may include an ultraviolet absorber.

Examples of the ultraviolet absorber include octyl methoxycinnamate, octyl dimethoxybenzylidene dioxoimidazolidine propionate, hexyl diethylaminohydroxybenzoyl benzoate, t-butylmethoxydibenzoylmethane, octyl triazone, 2-ethylhexyl paramethoxycinnamate. 2- (2Hydroxy-5-t-butylphenyl) -2H-benzotriazole, 2-methoxy-1-methylethyl acetate, 2- (2H-benzotriazol-2-yl) -4,6-bis (1 Organic ultraviolet absorbers such as -methyl-1-phenylethyl) phenol, or inorganic powder ultraviolet scattering / absorbers such as zinc oxide, silica, and titanium oxide. These may be used alone or in combination.

[Protective layer forming step]
In the protective layer forming step, a protective layer may be formed on the image layer. As a method for forming the protective layer, for example, the protective ink may be ejected toward the image layer by an ink jet method. The ink jet method may be either a thermal method or a piezo method, but a piezo method is more preferable.

In the case of a thermal type head, bubbles are generated at a high temperature due to its ejection principle, and the ink is likely to splash around the head due to the ink boiling. Here, in the case of a type that does not re-dissolve with the same ink once dried as an aqueous latex ink, the ink film scattered and adhered to the periphery of the nozzle gradually reaches the inside of the nozzle opening, and finally There is a risk of closing the nozzle. Therefore, in order to use the aqueous latex ink for the thermal ink jet, it is necessary to add a solvent having poor drying property, which may cause bleeding. On the other hand, the piezo method has no problem due to such a thermal method, and the ink hardly scatters around the head, so that a solvent having good drying property can be used.

In addition, from the viewpoint of further suppressing re-dissolution of the ink, the resin in the aqueous latex ink preferably has a high molecular weight. However, if the piezo method is used, the aqueous latex ink composed of the resin having a high molecular weight is suitably ejected. be able to.

<Image forming apparatus>
Next, an embodiment of an image forming apparatus according to the present invention will be described with reference to FIG. FIG. 1 is a diagram schematically showing a configuration of an ink jet recording apparatus (image forming apparatus) 100 which is an embodiment of an image forming apparatus according to the present invention.

The ink jet recording apparatus 100 applies an ink for forming an image layer on the medium 200 (hereinafter referred to as “image ink” for convenience of description) and a protective ink by ink jet, and an image protection method according to the present invention. This is for making a printed matter in which the image is protected.

The ink jet recording apparatus 100 includes a carriage 1, a guide mechanism 4, a platen 5, a control unit 10, a driving roller 6, and a driven roller 7.

The carriage 1 includes an image ink head (image ink discharge portion) 2 and a protection ink head (protection ink discharge portion) 3.

The direction of movement of the carriage 1 is defined by the guide mechanism 4 and reciprocates in the direction of arrow X. As a result, the carriage 1 scans the medium 200.

The image ink head 2 is a head for ejecting image ink to provide an image layer on the medium 200. When the carriage 1 scans the medium 200, image ink is ejected from the image ink head 2 based on predetermined image information. The ejection of ink from the image ink head 2 is controlled by an image ink head control unit (image ink ejection unit control means) 11 described later. Note that the inkjet recording apparatus 100 may include a heating unit such as a heater for curing the aqueous latex ink for the case of using the aqueous latex ink as the image ink.

The protective ink head 3 is a head that discharges protective ink in order to provide a protective layer. When the carriage 1 scans the medium 200, protective ink is ejected from the protective ink head 3 based on predetermined image information. The discharge of the protective ink from the protective ink head 3 is controlled by a protective ink head control unit (protective ink discharge unit control means) 12 described later. Note that the protective ink discharge section provided in the image forming apparatus according to the present invention may be an inkjet head as in the present embodiment, or a valve jet. Since the protective layer often does not require high resolution, it can be used sufficiently with a valve jet.

The guide mechanism 4 is a mechanism that regulates the moving direction of the carriage 1. The carriage 1 is attached to the guide mechanism 4 so that it can move in the direction of the arrow X, which is the length direction of the guide mechanism 4.

The platen 5 is a table on which the medium 200 to be printed is placed. On the platen 5, the medium 200 receives the image ink and the protective ink.

The driving roller 6 moves the medium 200. Further, when the driving roller 6 winds up the medium 200 wound around a driven roller 7 described later, the medium 200 moves.

The driven roller 7 is for assisting the conveyance of the medium 200 by the driving roller 6. A medium 200 is wound around the driven roller 7, and the medium 200 is supplied to the carriage 1 by being rotated.

The control unit 10 controls the operation of the ink jet recording apparatus 100. The control unit 10 includes an image ink head control unit 11 and a protective ink head control unit 12.

The image ink head control unit 11 controls the image ink head 2 so as to eject image ink based on image information indicating an image formed on the medium 200. The image information can be obtained, for example, by input from the user.

The protective ink head control unit 12 controls the protective ink head 3 so as to discharge the protective ink so as to provide a protective layer on the image.

The specific control method is not particularly limited. For example, an area for providing a protective layer is calculated from information indicating an image formed on the medium 200, information indicating an area for discharging the protective ink is created, and the protective ink is discharged based on the information. The protective ink head 3 may be controlled. Alternatively, the user or the like may directly receive input of information indicating a region where the protective ink is to be ejected, and the protective ink head 3 may be controlled to eject the protective ink based on the information.

Next, an example of the head arrangement will be described in more detail with reference to FIGS. FIG. 2 is a diagram illustrating an example of the arrangement of heads included in the inkjet recording apparatus 100. FIG. 3 is a diagram illustrating another example of the arrangement example of the heads included in the inkjet recording apparatus 100.

First, an example of the arrangement of heads shown in FIG. 2 will be described. In the head arrangement example shown in FIG. 2, heads H1, H2, H3, and H4, which are Y, M, C, and K ink heads, are arranged in the scanning direction of the head. Further, a head H5 (protective ink head 3) for discharging protective ink is also arranged in the head scanning direction together with the head H1, head H2, head H3, and head H4.

When the heads H1 to H5 are arranged in this way to form the image layer and the protective layer, first, when the entire heads H1 to H5 scan, the inks of Y, M, C, and K are transferred from the heads H1 to H4. Are appropriately discharged to form an image layer. Thereafter, the heads H1 to H5 return to the origin of the scanning. Meanwhile, the ink in the image layer is dried and cured. Next, the heads H1 to H5 scan the medium 200 again without moving the medium 200 in the sub-scanning direction. At this time, the protective ink is ejected from the head H5. In this way, a protective layer can be formed on the image layer. Note that the sub-scanning direction is a direction perpendicular to the scanning direction and parallel to the surface of the medium 200. That is, the direction in which the medium 200 is conveyed.

Next, an example of the arrangement of the heads shown in FIG. 3 will be described. In the arrangement example of the head shown in FIG. 3, heads H1, H2, H3, and H4, which are Y, M, C, and K ink heads, are arranged in the scanning direction of the head. The head H5 (protective ink head 3) for discharging the protective ink is arranged at a position shifted in the sub-scanning direction together with the head H1, the head H2, the head H3, and the head H4.

When the heads H1 to H5 are arranged in this way to form the image layer and the protective layer, first, when the entire heads H1 to H5 scan, the inks of Y, M, C, and K are transferred from the heads H1 to H4. Are appropriately discharged to form an image layer. Thereafter, the heads H1 to H5 return to the origin of the scanning. Meanwhile, the ink in the image layer is dried and cured. Next, the medium 200 is moved in the sub-scanning direction, and the heads H1 to H5 scan the medium 200 again. At this time, the protective ink is ejected from the head H5 onto the image layer formed by the ink ejected from the heads H1 to H4 in the previous scan. In this way, a protective layer can be formed on the image layer.

Further, in this case, while the protective ink is ejected from the head H5, the heads H1 to H4 can newly eject Y, M, C, and K inks to form a new image layer. Therefore, an image protected by the protective layer can be produced in a shorter time. It should be noted that a time difference sufficient for the image layer to dry is preferably set until the next scanning.

<Printed matter>
In the printed material according to the present invention, an image layer is provided on a recording medium, and a protective layer for protecting the image layer is provided on the image layer, and the protective layer is water or hydrophilic. And an organic solvent and a resin, and the resin is formed of an ink that is emulsified or suspended in the water or a hydrophilic organic solvent.

The description of the image layer, the protective layer, and the aqueous latex ink is the same as the description in the section <Image protection method> above. The printed matter according to the present invention is obtained by protecting the recording medium on which the image is printed by the image protection method according to the present invention, and is preferably obtained by, for example, the image forming apparatus according to the present invention.

In the printed material according to the present invention, the image is protected by the image protection method according to the present invention, so that the image is not eroded by the solvent of the protective layer and the surface is smooth.

<Image protection composition>
The composition for image protection according to the present invention contains water or a hydrophilic organic solvent and a resin, and the resin is emulsified or suspended in the water or the hydrophilic organic solvent.

That is, it is a composition for using aqueous latex ink for the purpose of image protection. The explanation for the water-based latex ink is the same as that in the section <Image protection method> above.

Since it can be used to protect an image by the image protection method according to the present invention, it is possible to provide a printed material in which the image is not eroded by the solvent of the protective layer and the surface is smooth.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in the embodiments are also included. It is included in the technical scope of the present invention.

<Additional notes>
As described above, the inkjet recording apparatus 100 includes the image ink head 2 that ejects ink for forming an image layer and the protective ink that ejects protective ink for forming a protective layer for protecting the image layer. A head 3, an image ink head controller 11 that controls the image ink head 2 so as to eject ink based on image information indicating an image for forming an image layer, and protective ink; And a protective ink head control unit 12 that controls the protective ink head 3 so as to eject the ink.

The image protection method according to the present invention can be carried out, and a printed matter that protects the image protected by the image protection method can be produced.

The present invention can be used for image printing of media such as paper and fabric.

Claims (10)

A protective layer forming step of forming a protective layer for protecting the image layer on the image layer;
The image protection method, wherein the protective layer is formed of an aqueous latex ink using an inkjet method. 2. The image protection method according to claim 1, wherein the image layer is formed of an aqueous latex ink using an inkjet method. The image protection method according to claim 1, wherein a piezo method is used as the ink jet method. A protective layer forming step of forming a protective layer for protecting the image layer on the image layer;
The image layer is formed using an inkjet method with an ink containing a thermoplastic resin having a lipophilic group as a binder,
The image protection method, wherein the protective layer is formed of a water-based ink whose main component is water or a hydrophilic organic solvent. The image protection method according to claim 4, wherein the water-based ink is a water-based latex ink. 5. The image protection method according to claim 4, wherein the image layer is formed of an aqueous latex ink using an inkjet method. The image protection method according to any one of claims 1 to 6, wherein the protective layer contains an ultraviolet absorber. An image ink ejecting section for ejecting ink for forming an image layer;
A protective ink discharge part for discharging a protective ink for forming a protective layer for protecting the image layer onto the image layer;
An image ink discharge section control means for controlling the image ink discharge section so as to discharge ink based on image information indicating an image for forming the image layer;
An image forming apparatus comprising: a protective ink discharge unit control unit that controls the protective ink discharge unit to discharge the protective ink onto the image layer so as to form the protective layer. An image layer is provided on the recording medium,
A protective layer for protecting the image layer is provided on the image layer,
The printed matter, wherein the protective layer is formed from an aqueous latex ink. An image protecting composition comprising water or a hydrophilic organic solvent and a resin, wherein the resin is emulsified or suspended in the water or the hydrophilic organic solvent.

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