JP2014186055A - Image forming method and manufacturing method of pressure-bonded postcard - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming method suitable for manufacturing of a pressure-bonded sheet, in particular, an image forming method in which a pressure-bonded layer can be peeled off without causing peel-off of an image processed on the pressure-bonded postcard.SOLUTION: An image forming method includes the steps of: forming an image layer on a support with colored toners containing a binder resin and a colorant; forming a transparent layer on the image layer with a transparent toner containing a binder resin and a mold release agent; and forming a peelable pressure-bonded layer on the transparent layer, in which the transparent layer has higher hardness than that of the image layer.

Description

  The present invention relates to an image forming method and a method for manufacturing a pressure-sensitive postcard.

A postcard-sized pressure-bonded sheet is called a pressure-bonded postcard. Crimp postcards can be used at the same rate as regular postcards. For this reason, the pressure-bonded postcard is used in place of the sealed letter, and the concealed description can be viewed by peeling. Crimp postcards are delivered concealing the written items, and the addressed person is peeled off and the written items are read. With a postcard, confidential documents can be used in postcard format instead of sealed letters.
As a conventional technique, a predetermined adhesive information is printed inside a crimped postcard in half, and then a liquid adhesive is applied or a pressure sensitive adhesive sheet is sandwiched in order to complete the postcard for posting by pressing. Yes.

An electrophotographic powder adhesive for postcards is also disclosed.
Patent Document 1 discloses a powder adhesive for a postcard using an electrophotographic method. Specifically, Patent Document 1 is configured so that it can be applied to a paper surface by development, transfer, and fixing steps by electrophotography, has a cyclic polyolefin resin as a basic structure, contains 40% or more of the cyclic polyolefin resin, and is a thermoplastic elastomer. A powder adhesive containing 30% or less is disclosed.

  Patent document 2 provides an adhesive for pressure-sensitive postcards used for an electrophotographic printer. Specifically, Patent Document 2 discloses a pressure-sensitive adhesive for postcards containing a hydrocarbon resin as a main component, and the hydrocarbon resin contains a copolymer of cycloolefin and ethylene.

JP 2008-170659 A JP 2007-45861 A

  Problems to be solved by the present invention are firstly to provide an image forming method suitable for the production of a pressure-bonded sheet, and secondly, even if processed into a pressure-bonded postcard, it does not peel off at the time of mailing, and It is an object of the present invention to provide an image forming method in which, after mailing, when a recipient peels, the image is peeled off without causing peeling. Another problem to be solved by the present invention is to provide a method for producing a crimped postcard.

The above problems have been solved by the following means <1> and <5>. They are listed together with <2> to <4> which are preferred embodiments.
<1> A step of forming an image layer with a colored toner containing a binder resin and a colorant on a support; a transparent layer with a transparent toner containing a binder resin and a release agent on the image layer; An image forming method comprising: a step of forming, and a step of forming a peelable pressure-bonding layer on the transparent layer, wherein the transparent layer has a hardness higher than that of the image layer;
<2> The image forming method according to <1>, wherein the hardness is a hardness based on an atomic force microscope (AFM) measurement,
<3> The image forming method according to <1> or <2>, wherein the transparent toner contains Fischer-Tropsch wax as a release agent.
<4> The image forming method according to any one of <1> to <3>, wherein the pressure-bonding layer is a pressure-bonding layer obtained by curing an ultraviolet curable composition.
<5> The pressure-bonding layer according to any one of <1> to <4>, wherein the pressure-bonding layer is a pressure-bonding layer obtained by curing an ultraviolet curable composition containing an ethylenically unsaturated compound, a photopolymerization initiator, and a filler. Image forming method,
<6> A method for producing a pressure-sensitive postcard, further comprising a step of pressure-bonding the pressure-bonding layers formed by the image forming method according to any one of <1> to <5>.

According to the invention described in <1> above, it is possible to provide an image forming method in which image peeling is reduced when the pressure-bonded sheet is peeled as compared with the case where the present configuration is not provided.
According to the invention described in <2> above, it is possible to provide an image forming method in which image peeling is reduced when the pressure-bonded sheet is peeled as compared with the case where the present configuration is not provided.
According to the invention described in <3>, it is possible to provide an image forming method in which image peeling is reduced as compared with the case of using another release agent.
According to the invention described in <4> above, it is possible to provide an image forming method in which image peeling is reduced as compared with the case where another pressure-bonding layer is used.
According to the invention described in <5> above, it is possible to provide an image forming method in which image peeling is further reduced as compared with the case where another pressure-bonding layer is used.
According to the invention described in <6> above, it is possible to provide a pressure-sensitive postcard with reduced image peeling when peeling.

It is a perspective conceptual diagram which shows an example of the folding state of a trifold crimping postcard. It is a conceptual diagram which shows an example of the surface of the paper support body of a trifold crimping postcard. It is a conceptual diagram which shows an example of the back surface of the paper support body of a trifold crimping postcard.

The image forming method of the present embodiment includes a step of forming an image layer with a colored toner containing a binder resin and a colorant on a support, and a binder resin and a release agent on the image layer. The method includes a step of forming a transparent layer with a transparent toner and a step of forming a peelable pressure-bonding layer on the transparent layer, wherein the transparent layer has a hardness higher than that of the image layer.
Hereinafter, the above embodiment will be described in the order of steps.
Here, both the image layer and the transparent layer are formed by development, transfer, and fixing steps by an electrophotographic method, and may be fixed sequentially or simultaneously.

<Process for forming image layer>
In this embodiment, a support is used as a substrate on which an image is formed. The support is preferably a paper support, and the type of the paper support is not particularly limited, but high-quality paper, medium-quality paper, art paper, coated paper, foam paper, and OCR paper are preferably used. The basis weight of the paper support preferably conforms to the regulations of the postal code when it is folded and crimped. The basis weight of the support varies depending on whether the overlapping of the pressure-bonded postcards is folded in half or in three. The basis weight of the paper support is preferably 75~90g / m ^2, and more preferably 81~86g / m ^2.
The paper support preferably has a paper interlayer strength in the range of 65 to 150 gf / 15 mm, and more preferably 70 to 120 gf / 15 mm. When it is within the above range, the paper is not broken when the pressure-bonding layer is peeled off, and peeling at the bonding surface of the pressure-bonding layer is obtained.

As described above, the colored image layer is formed by an electrostatic photography method using an electrostatic image developing toner (hereinafter also simply referred to as “toner”). By the electrostatic photographic method, an image layer colored with a colored toner is formed at a position closer to the support than the transparent layer by the development, transfer, and fixing processes.
The image layer may be black and white, monochrome, or full color. In the case where the image layer is two or more kinds of colored toners having different hues, a transparent layer made of transparent toner may be fixed after fixing these colored toners, or a plurality of colored toners and transparent toners may be fixed simultaneously. Then, the image layer and the transparent layer may be formed simultaneously.
The colored toner forming the image layer preferably has toner base particles containing a binder resin and a colorant as essential components, and an external additive as an optional component.

<Colored toner>
The colored toner contains a binder resin and a release agent, and preferably includes a binder resin, a colorant, and a release agent, and optionally contains other additives.

  The binder resin is not particularly limited. For example, styrenes such as styrene, parachlorostyrene, and α-methylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, acrylic Esters having a vinyl group such as lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc. ((meth) acrylic acid ester); acrylonitrile Vinyl nitriles such as methacrylonitrile; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isopropenyl ketone; ethylene, propylene, butadiene Homopolymer consisting of a monomer, such as polyolefins, or copolymers obtained by combining two or more kinds, even mixtures thereof. In addition, epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, etc., non-vinyl condensation resins, or a mixture of these with the vinyl resin, or vinyl monomers in the presence of these resins Examples thereof include a graft polymer obtained by polymerization.

Styrene resin, (meth) acrylic resin, and styrene- (meth) acrylic copolymer resin are obtained by known methods, for example, by combining styrene monomers and (meth) acrylic acid monomers alone or in appropriate combination. It is done. “(Meth) acryl” is an expression including both “acryl” and “methacryl”.
The polyester resin can be obtained by selecting and combining suitable ones from a dicarboxylic acid component and a diol component, and synthesizing them using a conventionally known method such as a transesterification method or a polycondensation method.

As a raw material monomer which polycondenses said polyester resin, polyhydric carboxylic acid, a polyol, hydroxycarboxylic acid, or mixtures thereof are mentioned, for example. In particular, the polycondensable monomer is preferably a polyvalent carboxylic acid, a polyol, and further an ester compound (oligomer and / or prepolymer) thereof. After undergoing a direct ester reaction or transesterification reaction, a polyester is obtained. What obtains resin is good. In this case, the polyester resin to be polymerized may take any form such as amorphous (amorphous) polyester resin (non-crystalline polyester resin), crystalline polyester resin, or a mixed form thereof.
In this embodiment, when a polycondensation resin is used as a binder resin, a polycondensation resin is obtained by polycondensation of at least one selected from the group consisting of polycondensable monomers, oligomers thereof and prepolymers. Among these, it is preferable to use a polycondensable monomer.

The polyvalent carboxylic acid is a compound containing two or more carboxyl groups in one molecule. Among these, dicarboxylic acid is a compound containing two carboxyl groups in one molecule and is preferably used. For example, oxalic acid, succinic acid, glutaric acid, maleic acid, adipic acid, β-methyladipic acid, azelain Acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, fumaric acid, citraconic acid, diglycolic acid, cyclohexane-3,5-diene-1,2-carboxylic acid, hexahydroterephthalic acid , Malonic acid, pimelic acid, peric acid, phthalic acid, isophthalic acid, terephthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-carboxyphenylacetic acid, p-phenylenediacetic acid, m-phenylenediacetic acid, o- Phenylenediacetic acid, diphenylacetic acid, diphenyl-p, p ' Dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, anthracene dicarboxylic acid, and cyclohexane dicarboxylic acid.
Examples of the polycarboxylic acid other than dicarboxylic acid include trimellitic acid, trimesic acid, pyromellitic acid, naphthalenetricarboxylic acid, naphthalenetetracarboxylic acid, pyrenetricarboxylic acid, pyrenetetracarboxylic acid, itaconic acid, glutaconic acid, Examples thereof include n-dodecyl succinic acid, n-dodecenyl succinic acid, isododecyl succinic acid, isododecenyl succinic acid, n-octyl succinic acid, n-octenyl succinic acid, and the like, and lower esters thereof. Furthermore, acid halides and acid anhydrides are not limited to this.
These may be used individually by 1 type and may use 2 or more types together.
In addition, lower ester means that the carbon number of the alkoxy part of ester is 1-8, and it is preferable that carbon number is 1-5. Specific examples include methyl ester, ethyl ester, n-propyl ester, isopropyl ester, n-butyl ester, and isobutyl ester.

A polyol is a compound containing two or more hydroxyl groups in one molecule. Among these, diol is a compound containing two hydroxyl groups in one molecule. Specifically, for example, as diol, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,14-eicosandecanediol, diethylene glycol, triethylene glycol , Dipropylene glycol, polyester Lenglycol, polypropylene glycol, polytetramethylene ether glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,4-butenediol, neopentyl glycol, 1,4-cyclohexanediol, polytetramethylene glycol, Examples include hydrogenated bisphenol A, bisphenol A, bisphenol F, bisphenol S, and alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adducts of the above bisphenols. Among these, preferred are alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols, and particularly preferred are alkylene oxide adducts of bisphenols and alkylene glycols having 2 to 12 carbon atoms. It is combined use with.
In order to facilitate water dispersibility, carboxy group-containing diols such as 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid and 2,2-dimethylolvaleric acid are preferably used.

Examples of trihydric or higher alcohols include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, hexamethylolmelamine, hexaethylolmelamine, tetramethylolbenzoguanamine, tetraethylolbenzoguanamine, sorbitol, trisphenol PA, phenol novolac, Examples thereof include cresol novolac, and alkylene oxide adducts of the above trivalent or higher polyphenols. These may be used individually by 1 type and may use 2 or more types together.
In addition, an amorphous resin or a crystalline resin can be easily obtained by combining these polycondensable monomers.

  When a crystalline polyester resin is used as the binder resin, 1,9-nonanediol and 1,10-decanedicarboxylic acid, or polyester obtained by reacting cyclohexanediol and adipic acid, 1,6-hexanediol and Polyester obtained by reacting sebacic acid, polyester obtained by reacting ethylene glycol and succinic acid, polyester obtained by reacting ethylene glycol and sebacic acid, 1,4-butanediol and succinic acid Mention may be made of polyesters obtained by reaction. Among these, polyesters obtained by reacting 1,9-nonanediol and 1,10-decanedicarboxylic acid and 1,6-hexanediol and sebacic acid are more preferable, but not limited thereto.

  Moreover, hydroxycarboxylic acid can also be used instead of a polyol and polycarboxylic acid. Specific examples of the hydroxycarboxylic acid include hydroxyheptanoic acid, hydroxyoctanoic acid, hydroxydecanoic acid, hydroxyundecanoic acid, malic acid, tartaric acid, mucoic acid, and citric acid.

  The weight average molecular weight of the polycondensation resin obtained by polycondensation of the polycondensable monomer is preferably 1,500 or more and 40,000 or less, and preferably 3,000 or more and 30,000 or less. More preferred. When the weight average molecular weight is 1,500 or more, the cohesive force of the binder resin is good and the hot offset property is excellent, and when it is 40,000 or less, the hot offset property is excellent and the minimum fixing temperature is excellent. This is preferable. Further, it may be partially branched or cross-linked by selecting the carboxylic acid valence or alcohol valence of the monomer.

  Moreover, it is preferable that the acid value of the polyester resin obtained is 1 mg * KOH / g or more and 50 mg * KOH / g or less. The first reason is that control of the particle size and distribution of the toner in the aqueous medium is indispensable for practical use as a high-quality toner, and the acid value is 1 mg · KOH / g or more. In the granulation step, sufficient particle size and distribution can be achieved, and when used in toner, sufficient chargeability can be obtained. Further, when the acid value of the polyester to be polycondensed is 50 mg · KOH / g or less, a sufficient molecular weight can be obtained for obtaining image quality strength as a toner at the time of polycondensation. The dependence of the charging property on the environment is small, and the image reliability is excellent.

When an amorphous polyester resin is used, the glass transition temperature Tg of the amorphous polyester resin is preferably 50 to 80 ° C, and more preferably 50 to 65 ° C. When the Tg is 50 ° C. or more, the cohesive force of the binder resin itself in a high temperature range is good, and thus the hot offset property is excellent at the time of fixing. Further, when Tg is 80 ° C. or less, sufficient melting is obtained and the minimum fixing temperature is hardly increased.
The glass transition temperature of the binder resin refers to a value measured by a method (DSC method) defined in ASTM D3418-82.

  When using a styrene resin, a (meth) acrylic resin or a copolymer resin thereof as a binder resin, the weight average molecular weight Mw is 20,000 or more and 100,000 or less, and the number average molecular weight Mn is 2,000 or more and 30,000 or less. It is preferable to use the thing of the range. On the other hand, when a polyester resin is used as the binder resin, a resin having a weight average molecular weight Mw of 5,000 or more and 40,000 or less and a number average molecular weight Mn of 2,000 or more and 10,000 or less may be used. preferable.

  The colorant used in the color toner is not particularly limited as long as it is a known colorant. For example, carbon black such as furnace black, channel black, acetylene black, and thermal black, inorganic such as bengara, bitumen, and titanium oxide. Pigments, Fast Yellow, Disazo Yellow, Pyrazolone Red, Chelate Red, Brilliant Carmine, Para Brown and other azo pigments, copper phthalocyanine, metal-free phthalocyanine and other phthalocyanine pigments, flavantron yellow, dibromoanthrone orange, perylene red, quinacridone red, di Examples thereof include condensed polycyclic pigments such as oxazine violet.

As the colorant, a surface-treated colorant may be used as necessary, or it may be used in combination with a dispersant. A plurality of colorants may be used in combination.
The content of the colorant is preferably in the range of 1% by weight to 30% by weight with respect to the total weight of the binder resin.

  Examples of the release agent used in the color toner include hydrocarbon waxes; natural waxes such as carnauba wax, rice wax, and candelilla wax; synthetic or mineral / petroleum waxes such as montan wax; fatty acid esters and montanic acid. An ester wax such as an ester is exemplified, and one of these is used, or two or more are used in combination.

<Process for forming transparent layer>
In this embodiment, a transparent layer made of a transparent toner is formed on the image layer formed on the paper support by electrophotography. The transparent layer is preferably formed so as to cover the colored image, and is preferably formed uniformly in the image forming region on the support.
It is preferable that the transparent toner contains a binder resin and a release agent, does not substantially contain a colorant, and does not contain a colorant at all.
The binder resin used for the transparent toner is selected from the group of binder resins exemplified for the colored toner.

The binder resin of the transparent toner is preferably the same type as the binder resin of the above colored toner. By using such a combination of the same type, the adhesion between the image layer and the transparent layer can be improved. It is preferable to use a polyester resin for the colored toner and the transparent toner.
In this case, the polyester resin used for the transparent toner is more preferable than the polyester resin used for the colored toner so that the image layer formed of the colored toner has a higher hardness than the transparent layer formed of the transparent toner. However, it is one of preferred embodiments to combine them so as to have a large weight average molecular weight and to add a small amount of a yellow pigment or a white pigment to such an extent that transparency is not impaired.
As another embodiment, the fixed transparent layer has a higher hardness than the image layer by using a resin having the same chemical composition and molecular weight as the colored toner and the transparent toner, and adding a plastic compound to the colored toner. It is also possible to adopt a mode in which such combinations are included.
Examples of the yellow pigment include C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Organic pigments such as CI Pigment Yellow 185 are preferred. The white pigment is preferably silica, titania, alumina or the like. The reason is considered to be that the resin enters between the binder resins, increases in viscosity due to the interaction, and acts like a resin having a large molecular weight.
Further, as the compound having plasticity added to the colored toner, metal soap, higher ester compound, higher alcohol and the like can be used.
The method for increasing the hardness of the transparent toner and the means for decreasing the hardness of the colored toner may be separate, but are preferably performed simultaneously.

As release agents used for transparent toners, hydrocarbon waxes; natural waxes such as carnauba wax, rice wax, and candelilla wax; synthetic or mineral / petroleum waxes such as montan wax; fatty acid esters, montanate esters, etc. And ester waxes.
As the release agent in the transparent toner of the present embodiment, ester wax, carnauba wax, and hydrocarbon wax are preferably used, and hydrocarbon wax is more preferably used. Among the hydrocarbon waxes, low molecular weight polyethylene, low molecular weight polypropylene, and Fischer-Tropsch wax are preferable, and Fischer-Tropsch wax is more preferably used.
The advantage of using Fischer Trop push wax as a release agent for transparent toner is that it has high sharp melt properties, and the release agent can easily ooze out on the surface of the image, thereby suppressing unevenness of the release agent on the image surface. There is.
The content of the release agent in the transparent toner of the exemplary embodiment is preferably 3 to 15% by weight, and more preferably 3 to 12% by weight with respect to the total weight of the toner. When the amount is within the above range, a sufficient release effect can be obtained at the time of fixing, the hot offset resistance is excellent, and the storage stability is excellent.

In the present embodiment, the colored toner and the transparent toner may be fixed separately or may be fixed simultaneously. The colored toner may be a monochrome toner using a black toner, or may be a four-color full-color ink set including three primary colors of cyan, magenta, and yellow and subtracting black.
A preferable fixing condition is an aspect in which the colored toner and the transparent toner are fixed simultaneously.

<Step of forming a peelable pressure-bonding layer>
In order to conceal confidential parts such as postcards, a peelable pressure-bonding layer is formed on the transparent layer. The pressure-bonding layer means a pressure-sensitive adhesive layer. When the pressure-bonding layer is formed, it is in a dry state of finger erosion. Even in a state where the pressure-bonding layer has been peeled off after pressure bonding, the pressure-bonded layer is in a dry state.
The material for forming the pressure-bonding layer is selected from several pressure sensitive adhesives. One of them is a pressure-sensitive adhesive composition in which a non-adhesive component is blended with a rubber adhesive, and a pressure-bonding layer is formed by applying and drying an aqueous composition on a required surface of a paper support.

The pressure-bonding layer is provided on the entire surface that needs to be bonded. There is a case where the support is one side and a case where the support is both sides. As one embodiment, when there is an image layer having information to be concealed on one side of an A5 size paper support and a transparent layer laminated thereon, a pressure-bonding layer is provided on the entire printing surface, and then at the center. Fold and crimp to create a bi-fold crimp postcard.
When the postcard is a tri-fold type, it is preferable to form a pressure-bonding layer on both sides of the support as shown in FIGS. In this case, a pressure-bonded postcard folded in a Z shape is formed.
As described above, the postcard is typically a two-fold type or a three-fold type. In any case, the spread page on which the information to be treated as confidential is written and crimped is peeled off by the addressee after mailing. The pressure-bonding layer that is a pressure-sensitive adhesive layer that is bonded by pressure or heat and pressure is preferably provided uniformly on the paper support, and is preferably provided on the outermost layer of the paper support.

The peelable pressure-bonding layer is formed of a conventionally known material.
An example of the material forming the pressure-bonding layer is a pressure-sensitive adhesive in which a non-adhesive component is blended with a synthetic rubber-based adhesive or a natural rubber-based adhesive. After the image forming step and the transparent toner layer forming step, a pressure-sensitive adhesive composition in which a non-adhesive component is blended with a natural rubber-based adhesive or a synthetic rubber-based adhesive is applied and dried to provide a pressure-bonding layer.
The natural rubber adhesive includes natural rubber latex, vulcanized natural rubber latex, and natural rubber latex obtained by graft copolymerization with methyl methacrylate (MMA).
As the non-adhesive component, an inorganic filler and / or an organic filler is used. Examples of the inorganic filler include silica, clay, calcium carbonate, alumina, and mica, and silica is preferable. Examples of the organic filler include starch such as cellulose powder and corn starch, styrene particles, and PMMA particles. As the inorganic filler and the organic filler, those having a number average particle diameter of 4 to 40 μm are preferably used. The adhesive strength is adjusted according to the particle size and blending amount of the organic filler.
The amount of all non-adhesive components to 100 parts by weight of all rubber components is preferably 50 to 500 parts by weight, and more preferably 200 to 400 parts by weight.
In addition to the natural rubber adhesive and the non-adhesive component, a water-soluble polymer may be used in combination. Examples of the water-soluble polymer include carboxymethyl cellulose (CMC) and polyvinyl alcohol.
The coating amount (solid content) of the pressure-sensitive layer is preferably ² to 10 g / m ² , and more preferably 3 to 7 g / m ² .

The peelable pressure-bonding layer can also be formed by blending the non-adhesive component with a heat-sensitive adhesive aqueous emulsion.
Such an aqueous emulsion is known, and has a glass transition temperature of −10 ° C. or less (obtained by emulsion polymerization of a radically polymerizable monomer mainly composed of (meth) acrylic acid alkyl ester in an aqueous medium). An aqueous emulsion containing a (meth) acrylic acid alkyl ester polymer can be exemplified.
This aqueous emulsion has (meth) acrylic acid alkyl ester as a main component, and if necessary, other radical polymerizable monomer (hereinafter referred to as “copolymerization”) that can be copolymerized with (meth) acrylic acid alkyl ester. Obtained in combination with a small amount (preferably 40% by weight or less) of a small amount (sometimes referred to as a “soluble monomer”) in an aqueous medium.
As said (meth) acrylic-acid alkylester used for manufacture of aqueous | water-based emulsion, the (meth) acrylic-acid alkylester whose carbon number of the alkyl group is 1-9 is preferable, for example, methyl (meth) acrylate, ( (Meth) ethyl acrylate, (meth) acrylic acid isopropyl, (meth) acrylic acid n-propyl, (meth) acrylic acid n-butyl, (meth) acrylic acid isobutyl, (meth) acrylic acid hexyl, (meth) acrylic acid Examples include cyclohexyl, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate and isononyl (meth) acrylate. ) One or more of acrylic acid alkyl esters can be used. A more preferable (meth) acrylic acid alkyl ester used in the production of the aqueous emulsion is a (meth) acrylic acid alkyl ester having an alkyl group having 4 to 9 carbon atoms.
A copolymer obtained by copolymerizing the above aqueous emulsion with α, β-ethylenically unsaturated carboxylic acid and other radical polymerizable monomers, and a part of the carboxyl groups in the copolymer Alternatively, it is also preferable to use a water-soluble or water-dispersible polymer (carboxyl group-containing polymer) having a Tg of 20 ° C. or higher, which is neutralized with a base having a boiling point of 110 ° C. or lower.
Specific examples of the aqueous emulsion and the carboxyl group-containing polymer are described, for example, in JP-A-10-36788.
The blending amount of all non-adhesive components with respect to 100 parts by weight of the total aqueous emulsion component is preferably 50 to 500 parts by weight, and more preferably 200 to 400 parts by weight.
The coating amount (solid content) of the pressure-sensitive layer is preferably ² to 10 g / m ² , and more preferably 3 to 7 g / m ² .

In the above-mentioned step of forming the pressure-bonding layer, a material that is cured by heat or actinic radiation to form the pressure-bonding layer can be used. In particular, an ultraviolet curable composition using ultraviolet rays as actinic radiation can be preferably used. This ultraviolet curable composition is preferably a fully curable composition containing neither water nor an organic solvent.
Various compositions can be used as the ultraviolet curable composition. An example of the ultraviolet curable composition is a composition containing a photopolymerization initiator, an ethylenically unsaturated compound, and a filler that is a non-adhesive component.
The ultraviolet curable pressure-bonding composition, which is a pressure-sensitive adhesive precursor composition used for forming the pressure-bonding layer, will be described.
This ultraviolet curable pressure-bonding composition contains an ethylenically unsaturated compound, a photopolymerization initiator, and a filler. As the ethylenically unsaturated compound, a monofunctional (meth) acrylic acid ester compound (also referred to as “monofunctional acrylate”) and a polyfunctional (meth) acrylic acid ester compound (also referred to as “polyfunctional acrylate”) are used in combination. It is preferable. In any case, one or more compounds may be used in combination.

The monofunctional acrylate includes (meth) acrylic acid esters of alcohol having 2 to 10 carbon atoms, and examples thereof include n-butyl acrylate and isobutyl acrylate.
The monofunctional acrylate preferably contains a urethane acrylate oligomer having an average molecular weight of 1,500 to 30,000. In this urethane acrylate oligomer, the homopolymer obtained by polymerization thereof preferably has a glass transition temperature of −10 ° C. or lower.
The polyfunctional (meth) acrylate includes an ester of a polyol and (meth) acrylic acid, and the polyol may have an ethylene oxide group. The polyfunctional (meth) acrylate is a (meth) acrylic acid ester containing a plurality of ethylenically unsaturated groups in one molecule, and is not blended with respect to all monofunctional (meth) acrylates, or 0 to 20% by weight is blended.

The ultraviolet curable pressure-bonding composition that can be used in the present embodiment contains a polymerization initiator.
The polymerization initiator is a compound that absorbs external energy such as the actinic radiation to generate a polymerization initiating species. A polymerization initiator may be used individually by 1 type, and may use 2 or more types together.
The polymerization initiator that can be used in the present embodiment is preferably a radical polymerization initiator, more preferably a radical photopolymerization initiator, an α-hydroxyketone compound, a monoacylphosphine compound, an aromatic onium salt compound. More preferred are organic peroxides, thio compounds, hexaarylbiimidazole compounds, ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, and compounds having a carbon halogen bond. Specific examples of these polymerization initiators include radical polymerization initiators described in JP-A-2008-208190. Among these, aromatic ketones and acyl phosphine compounds are preferable, and α-hydroxy ketone compounds and acyl phosphine compounds are more preferable.

As the aromatic ketones, α-hydroxyketone compounds are preferable.
Specifically, for example, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-2-methyl-1-phenyl-propane- Examples include 1-one and 1-hydroxycyclohexyl phenyl ketone. Among them, a 1-hydroxycyclohexyl phenyl ketone compound is preferable. In the present embodiment, the 1-hydroxycyclohexyl phenyl ketone compound includes a compound in which 1-hydroxycyclohexyl phenyl ketone is substituted with an arbitrary substituent. As a substituent, it can select arbitrarily in the range which can exhibit the capability as a radical polymerization initiator, Specifically, a C1-C4 alkyl group can be illustrated.

  Preferred examples of the acylphosphine compound include acylphosphine oxide compounds described in JP-A-2008-208190, and among them, a monoacylphosphine oxide compound is more preferable.

  The composition for forming a pressure-bonding layer that can be used in this embodiment preferably contains an α-hydroxyketone compound and / or a monoacylphosphine oxide compound. From the viewpoints of curability and blocking resistance, α- The combined use of a hydroxyketone compound and a monoacylphosphine oxide compound is more preferable.

As the filler, a non-adhesive component filler used in combination with a rubber-based adhesive is used.
As the filler, an inorganic filler and / or an organic filler is used. Examples of the inorganic filler include silica, clay, calcium carbonate, alumina, and mica, and silica is preferable. Examples of the organic filler include starch such as cellulose powder and corn starch, styrene particles, and PMMA particles. As the inorganic filler and the organic filler, those having a number average particle diameter of 4 to 40 μm are preferably used. The adhesive strength is adjusted according to the particle size and blending amount of the organic filler.
The blending amount of all non-adhesive components with respect to 100 parts by weight of the ultraviolet curable component is preferably 50 to 500 parts by weight, and more preferably 200 to 400 parts by weight.

The precursor composition of the pressure-sensitive adhesive is preferably applied on a support having an image layer and a transparent layer so that the coating amount (solid content) is ² to 10 g / m ^2. It is more preferable to apply so as to be 7 g / m ² .
After applying the precursor composition to the support, the pressure-sensitive adhesive layer can be formed by irradiating active radiation or ultraviolet rays to cause the composition to undergo a photopolymerization reaction. The precursor composition is preferably a solventless type.

<Hardness>
In the present embodiment, the image layer formed from the colored toner on the support has a hardness smaller than that of the transparent layer formed from the transparent toner. In other words, the transparent layer has a higher hardness than the image layer.
The hardness of the image layer and the transparent layer are determined by measuring the cross section of the image layer and the transparent layer with an atomic force microscope (AFM) after cutting a sample including both layers on the support as a thin section in the cross-sectional direction. It is determined by measuring the hardness. A specific method for preparing and measuring a cross-sectional sample is as follows.
The cross-section sample was prepared by the following method. The sample was cut into a strip shape having a width of 1.5 mm and a length of 10 mm to obtain an elongated sample piece. The sample piece is submerged in a viscous liquid obtained by mixing 7 g of bisphenol A type liquid epoxy resin (Asahi Kasei Chemical Co., Ltd.) and 3 g of Zenamide 250 (Henkel Japan Co., Ltd.) as a curing agent. Cured for 2 days under. Next, the sample-embedded block was cut out so that the target sample could cut out the cured epoxy resin solid in the cross-sectional direction, and trimming was performed. As the block in which the sample was embedded, an ultramicrotome device LEICA ULTRACUT UCT (manufactured by Leica) was used. The knife to be used was Sumiknife SK2045 (wet type, manufactured by Sumitomo Electric Industries, Ltd.), the cutting conditions were adjusted in the direction of the sample cross section, and cutting was performed at a cutting speed of 2.0 mm / s and a thickness setting of 250 nm. The cut section was fixed on a sample table for hardness measurement.

The measurement of hardness with an atomic force microscope was performed in a contact mode, the detailed measurement conditions were measured at 25 ° C., and the hardness was measured in the nano-indentation mode of S-image manufactured by SII Nanotechnology. The measurement conditions are: measuring device: Allowable Drift Rate: 0.5 nm / s, Depth Limit: 1,000 nm, Frequency Target: 75 Hz, Harmonic Displacement Target: 1.0 nm, Strai Rate Target: 0.050 / s.
The hardness measured by AFM has a unit of GPa, and (transparent layer hardness / image layer hardness) is preferably in the range of 1.05-5.0, and in the range of 1.1-4.2. Is more preferable. When the hardness ratio is within this range, image peeling is unlikely to occur when the pressure-bonded postcard is peeled off.

In order to make the hardness of the transparent layer larger than the hardness of the image layer, one or more of the following means are adopted.
1) The same binder resin is used for both the transparent toner and the colored toner, and the average molecular weight of the binder resin of the transparent toner is made larger than the average molecular weight of the colored toner.
2) When a toner is prepared by an agglomeration method, the amount of polyvalent metal ions (Al ³⁺ ), which is an aggregating agent, is used more for the transparent toner than for the colored toner, thereby increasing the aggregation density of the transparent toner. increase.
3) A small amount of yellow pigment or white pigment is added to the transparent toner to such an extent that the transparency is not impaired.
4) Add a plastic compound to the colored toner.

<Toner production method>
In the exemplary embodiment, the colored toner essentially includes a binder resin and a colorant, and preferably includes a release agent, and the transparent toner essentially includes the binder resin and the release agent, and substantially does not include the colorant. . “Substantially free” refers to the extent that the degree of coloring is not noticed by the naked eye.
The toner base particles used in the exemplary embodiment are not particularly limited by the production method, and a known method can be used. Specific examples include the following methods.
The production of the toner base particles is obtained, for example, by a kneading and pulverizing method in which a binder resin, a colorant, a release agent, and a charge control agent, if necessary, are kneaded, pulverized, and classified; To change the shape of the particles by mechanical impact force or thermal energy; dispersion of emulsified binder resin, dispersion of colorant, release agent, and charge control agent as required An emulsion aggregation method in which toner particles are obtained by mixing, aggregating and heating and fusing the solution; emulsion polymerization of a polymerizable monomer of a binder resin, and a formed dispersion, a colorant, a release agent, and , An emulsion polymerization aggregation method to obtain toner particles by mixing with a dispersion such as a charge control agent, if necessary, and then fusing and heat-fusing; a polymerizable monomer for obtaining a binder resin, a colorant, A suspension polymerization method in which a release agent and, if necessary, a solution such as a charge control agent are suspended in an aqueous solvent for polymerization; Resin and a colorant, releasing agent, and dissolution suspension method and granulated with a solution such as a charge control agent is suspended in an aqueous solvent optionally; or the like can be used. In addition, a manufacturing method may be performed in which the toner base particles obtained by the above method are used as a core, and aggregated particles are further adhered and heat-fused to have a core-shell structure.
Among these, the toner of the exemplary embodiment is preferably a toner (emulsion aggregation toner) obtained by an emulsion aggregation method or an emulsion polymerization aggregation method.

  The particle diameter of the mother particles of the colored toner produced as described above is preferably in the range of 2 to 8 μm, more preferably in the range of 3 to 7 μm in terms of volume average particle diameter. When the volume average particle size is 2 μm or more, the fluidity of the toner is good and sufficient charging ability is imparted from the carrier, so that fogging in the background portion and density reproducibility are unlikely to occur. . Further, when the volume average particle size is 8 μm or less, the effect of improving the reproducibility, gradation and graininess of fine dots is good, and a high-quality image can be obtained. The volume average particle size is measured with Coulter Multisizer II (manufactured by Beckman Coulter, Inc.).

  The toner base particles are preferably pseudo-spherical from the viewpoint of improving developability and transfer efficiency and improving image quality. The sphericity of the toner base particles can be expressed by using the shape factor SF1 of the following formula, but the average value (average shape factor) of the shape factor SF1 of the toner base particles used in this embodiment is 160. Is preferably in the range of 115 or more and less than 155, and more preferably in the range of 120 or more and less than 140. When the average value of the shape factor SF1 is less than 160, good transfer efficiency is obtained and the image quality is excellent.

In the above formula, ML represents the maximum length of each toner base particle, and A represents the projected area of each toner base particle.
The average value of the shape factor SF1 (average shape factor) is obtained by taking 1,000 toner images magnified 250 times from an optical microscope to an image analyzer (LUZEX III, manufactured by Nireco Corporation), and the maximum From the length and the projected area, the value of the SF1 is obtained for each particle and averaged.

  The shape factor SF1 of the toner particles is preferably 125 or more and 140 or less, more preferably 125 or more and 135 or less, and further preferably 130 or more and 135 or less, and the shape factor SF2 is preferably 105 or more and 130 or less, more preferably 110 or more. 125 or less, more preferably 115 or more and 120 or less.

The shape factor SF2 of the toner particles is obtained as follows.
An image is taken by observing toner particles using a scanning electron microscope (for example, Hitachi, Ltd .: S-4100, etc.), and this image is captured by an image analyzer (for example, LUZEX III, manufactured by Nireco Corporation). For each of the 100 toner particles taken in, SF2 is calculated based on the following formula, and the average value is obtained as the shape factor SF2. In the electron microscope, the magnification was adjusted so that 3 or more and 20 or less external additives could be seen in one field of view, and the observation of a plurality of fields of view was combined to calculate SF2 based on the following formula.
Formula: Shape factor SF2 = (PM ² / (4 · A · π)) × 100
Here, in the formula, PM indicates the peripheral length of the toner particles. A represents the projected area of the toner particles. π represents a circumference ratio.

  The volume average particle size of the transparent toner particles is preferably 2 μm or more and 10 μm or less, and more preferably 4 μm or more and 8 μm or less.

The volume average particle diameter of the toner particles is measured using a Coulter Multisizer II (manufactured by Beckman-Coulter Co., Ltd.) with an aperture diameter of 50 μm. At this time, the measurement is performed after the toner particles are dispersed in an electrolyte aqueous solution (isoton aqueous solution) and dispersed by ultrasonic waves for 30 seconds or more.
As a measurement method, 0.5 to 50 mg of a measurement sample is added to 2 ml of a 5% aqueous solution of a surfactant, preferably sodium alkylbenzenesulfonate as a dispersant, and this is added to 100 to 150 ml of the electrolytic solution. The electrolytic solution in which the measurement sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 minute, and the particle size distribution of the particles is measured. The number of particles to be measured is 50,000.
For the measured particle size distribution, a cumulative distribution is drawn from the smaller diameter side with respect to the divided particle size range (channel), and the particle size at which 50% is accumulated is defined as the volume average particle size.

(Electrostatic image developer)
In the electrostatic image developing toner of this embodiment, both colored toner and transparent toner are preferably used as the electrostatic image developer.
The electrostatic image developer of this embodiment is not particularly limited except that it contains the electrostatic image developing toner of this embodiment, and can take an appropriate component composition depending on the purpose. When used alone, the toner for developing an electrostatic image of this embodiment is prepared as a one-component electrostatic image developer, and when used in combination with a carrier, it is prepared as a two-component electrostatic image developer. .
As a one-component developer, a method in which a charged toner is formed by frictional charging with a developing sleeve or a charging member, and development is performed according to an electrostatic latent image is also applied.

  In the present embodiment, the development method is not particularly defined, but the two-component development method is preferable. Further, the carrier is not particularly defined as long as the above conditions are satisfied. Examples of the carrier core material include magnetic metals such as iron, steel, nickel, and cobalt, alloys of these with manganese, chromium, rare earth, and the like, and Magnetic oxides such as ferrite and magnetite are mentioned, and from the viewpoint of core material surface properties and core material resistance, ferrite, particularly alloys with manganese, lithium, strontium, magnesium and the like are preferably mentioned.

  The carrier used in this embodiment is preferably formed by coating the surface of the core material with a resin. There is no restriction | limiting in particular as said resin, According to the objective, it selects suitably. For example, polyolefin resins such as polyethylene and polypropylene; polyvinyl resins and polyvinylidene resins such as polystyrene, acrylic resins, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether and polyvinyl ketone Vinyl chloride-vinyl acetate copolymer; styrene-acrylic acid copolymer; straight silicone resin composed of organosiloxane bond or modified product thereof; polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoroethylene, etc. Fluorine resin; Silicone resin; Polyester; Polyurethane; Polycarbonate; Phenol resin; Urea-formaldehyde resin, Melamine tree , Benzoguanamine resins, urea resins, amino resins such as polyamide resins, epoxy resins, per se known resins and the like. These may be used individually by 1 type and may use 2 or more types together. In the present embodiment, among these resins, it is preferable to use at least a fluorine resin and / or a silicone resin. The use of at least a fluorine-based resin and / or a silicone resin as the resin is advantageous in that the effect of preventing carrier contamination (impaction) due to toner and external additives is high.

  In the resin coating, it is preferable that resin particles and / or conductive particles are dispersed in the resin. Examples of the resin particles include thermoplastic resin particles and thermosetting resin particles. Among these, thermosetting resins are preferable from the viewpoint of relatively easily increasing the hardness, and resin particles made of nitrogen-containing resin containing N atoms are preferable from the viewpoint of imparting negative chargeability to the toner. In addition, these resin particles may be used individually by 1 type, and may use 2 or more types together. The average particle size of the resin particles is preferably 0.1 to 2 μm, and more preferably 0.2 to 1 μm. When the average particle size of the resin particles is 0.1 μm or more, the resin particles are excellent in dispersibility in the coating, whereas when the average particle size is 2 μm or less, the resin particles are not easily dropped from the coating.

  Examples of the conductive particles include metal particles such as gold, silver, and copper, carbon black particles, and surfaces of titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate powder, tin oxide, carbon black, metal And particles covered with the like. These may be used individually by 1 type and may use 2 or more types together. Among these, carbon black particles are preferable in terms of good production stability, cost, conductivity and the like. The type of carbon black is not particularly limited, but carbon black having a DBP oil absorption of 50 to 250 ml / 100 g is preferable because of excellent production stability. The coating amount of the resin, the resin particles, and the conductive particles on the surface of the core material is preferably 0.5 to 5.0% by weight, and preferably 0.7 to 3.0% by weight. More preferred.

The method for forming the coating is not particularly limited. For example, the resin particles such as crosslinkable resin particles and / or the conductive particles, and a styrene acrylic resin, a fluorine resin, a silicone resin as a matrix resin, etc. And a method of using a film-forming solution containing the above resin in a solvent.
Specifically, the carrier core material is immersed in the film forming liquid, a spray method in which the film forming liquid is sprayed on the surface of the carrier core material, and the carrier core material is floated by flowing air And kneader coater method in which the film forming solution is mixed and the solvent is removed. Among these, the kneader coater method is preferable in the present embodiment.

  The solvent used for the film-forming liquid is not particularly limited as long as it can dissolve only the resin as a matrix resin, and is selected from known solvents such as toluene, Aromatic hydrocarbons such as xylene, ketones such as acetone and methyl ethyl ketone, ethers such as tetrahydrofuran and dioxane, and the like. When the resin particles are dispersed in the coating, since the resin particles and the particles as the matrix resin are uniformly dispersed in the thickness direction and the tangential direction of the carrier surface, the carrier is used for a long time. Even when the coating is worn, it is possible to always maintain the same surface formation as when it is not used, and to maintain a good charge imparting ability for the toner over a long period of time. In the case where the conductive particles are dispersed in the coating, the conductive particles and the resin as the matrix resin are uniformly dispersed in the thickness direction and the tangential direction of the carrier surface. Even if the coating is worn out over a long period of time, the same surface formation as when not in use can be maintained, and carrier deterioration is prevented for a long period of time. In addition, when the said resin particle and the said electroconductive particle are disperse | distributed to the said film, the above-mentioned effect is exhibited simultaneously.

The electric resistance of the magnetic carrier formed as described above in the state of a magnetic brush under an electric field of 10 ⁴ V / cm is preferably 10 ⁸ to 10 ¹³ Ωcm. When the electric resistance of the magnetic carrier is 10 ⁸ Ωcm or more, the adhesion of the carrier to the image portion on the image carrier is suppressed, and the brush mark is difficult to appear. On the other hand, when the electrical resistance of the magnetic carrier is 10 ¹³ Ωcm or less, the generation of the edge effect is suppressed and a good image quality is obtained.
The electrical resistance (volume specific resistance) is measured as follows.
A measuring jig comprising a pair of 20 cm ² circular electrode plates (made of steel) connected to an electrometer (manufactured by KEITHLEY, trade name: KEITHLEY 610C) and a high-voltage power supply (trade name: FLUKE 415B). The sample is placed on the lower electrode plate so as to form a flat layer having a thickness of about 1 mm to 3 mm. Next, after the upper electrode plate is placed on the sample, a weight of 4 kg is placed on the upper electrode plate in order to eliminate the gap between the samples. In this state, the thickness of the sample layer is measured. Next, the current value is measured by applying a voltage to the bipolar plate, and the volume resistivity is calculated based on the following equation.
Volume resistivity = applied voltage × 20 ÷ (current value−initial current value) ÷ sample thickness In the above formula, the initial current is the current value when the applied voltage is 0, and the current value indicates the measured current value.

  In the two-component electrostatic charge image developer, the mixing ratio of the toner and the carrier of this embodiment is preferably 2 to 10 parts by weight of the toner with respect to 100 parts by weight of the carrier. Moreover, the preparation method of a developing agent is not specifically limited, For example, the method of mixing with a V blender etc. is mentioned.

(Image forming method)
As described above, the image forming method of the present embodiment includes a step of forming an image layer with a colored toner containing a binder resin and a colorant on a support, and the binder resin and the release layer on the image layer. A step of forming a transparent layer with a transparent toner containing a mold agent, and a step of forming a peelable pressure-bonding layer on the transparent layer.
Since the image forming method of the present embodiment is based on an electrostatic photography method, a latent image forming step for forming an electrostatic latent image on the surface of the image carrier, and the electrostatic latent image formed on the surface of the image carrier is treated with toner. A developing step of forming a toner image by developing with a developer, a transfer step of transferring the toner image to the surface of the transfer member, and a fixing step of fixing the toner image transferred to the surface of the transfer member. .
In addition, a cleaning process or the like may be included as necessary.

Each of the above steps is a general step per se, and is described in, for example, JP-A-56-40868 and JP-A-49-91231. Note that the image forming method of the present embodiment can be carried out by using a known image forming apparatus such as a copying machine or a facsimile machine.
The electrostatic latent image forming step is a step of forming an electrostatic latent image on an image carrier (photoconductor).
The developing step is a step of developing the electrostatic latent image with a developer layer on a developer holding member to form a toner image. The developer layer is not particularly limited as long as it contains the electrostatic image developing toner of this embodiment.
The transfer step is a step of transferring the toner image onto a transfer target. Examples of the transfer medium in the transfer process include an intermediate transfer medium and a recording medium such as paper.
In the fixing step, for example, there is a method of forming a copy image by fixing the toner image transferred onto the transfer paper by a heating roller fixing device in which the temperature of the heating roller is set to a constant temperature.
The cleaning step is a step of removing the electrostatic charge image developer remaining on the image carrier.
Further, the image forming method of the present embodiment preferably includes the cleaning step, and more preferably includes a step of removing the electrostatic charge image developer remaining on the image carrier with a cleaning blade.

  As the support, known materials can be used, for example, paper used for electrophotographic copying machines, printers, OHP sheets, etc. For example, the surface of plain paper is coated with resin or the like. Coated paper, art paper for printing, and the like can be suitably used, and a paper support for pressure-bonded postcards is particularly preferable.

The image forming method of the present embodiment preferably includes a step of bonding the formed pressure-bonding layers under pressure after the step of forming a peelable pressure-bonding layer. By this bonding step, a two-fold or three-fold crimping postcard is obtained.
You may heat in an adhesion | attachment process. The heating temperature is preferably a temperature of room temperature to 60 ° C.
The postcard is mailed, and the addressee peels off the crimped part, so that the items described in the confidential can be viewed.

Hereinafter, although this embodiment is described in detail based on an Example, this embodiment is not restricted to these Examples.
<Preparation of Amorphous Polyester Resin Dispersion A>
In a heat-dried two-necked flask, 10 mol parts of polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2,2) -2,2-bis (4- Hydroxyphenyl) 90 mol parts of propane, 80 mol parts of terephthalic acid, 20 mol parts of succinic acid, 0.05 mol parts of dibutyltin oxide with respect to the acid component (total number of moles of terephthalic acid and succinic acid) are put in a container. After introducing nitrogen gas into an inert atmosphere and raising the temperature, a copolycondensation reaction was carried out at 210 ° C. for 6 hours, and then the pressure was gradually reduced at 210 ° C. to produce an amorphous polyester resin A having a weight average molecular weight of 40,000. Was synthesized.

  After putting 300 parts by weight of the obtained amorphous polyester resin A, 1,000 parts by weight of ion-exchanged water, and 9 parts by weight of sodium dodecylbenzenesulfonate into an emulsification tank of a high-temperature, high-pressure emulsifier (Cavitron CD1010), After being heated and melted, it was dispersed at 110 ° C. at a flow rate of 3 L / m, 10,000 rpm for 30 minutes, passed through a cooling tank, solid content 30% by weight, and a non-crystalline polyester resin dispersion A having a volume average particle diameter D50v of 119 nm Was made.

<Preparation of Amorphous Polyester Resin Dispersion B>
The copolycondensation reaction was carried out at 210 ° C. for 9 hours, followed by reaction under the same conditions as the amorphous polyester resin A except that the pressure was gradually reduced at 210 ° C. A crystalline polyester resin B was synthesized, and an amorphous polyester resin dispersion B was prepared under the same conditions as the amorphous polyester resin dispersion A. The volume average particle diameter D50v was 122 nm.

<Preparation of Amorphous Polyester Resin Dispersion C>
The copolycondensation reaction was carried out at 210 ° C. for 12 hours, and then the reaction was carried out under the same conditions as for the amorphous polyester resin A except that the pressure was gradually reduced at 210 ° C. A crystalline polyester resin C was synthesized, and an amorphous polyester resin dispersion C was produced under the same conditions as the amorphous polyester resin dispersion A. The volume average particle diameter D50v was 125 nm.

<Preparation of Amorphous Polyester Resin Dispersion D>
The copolycondensation reaction was carried out at 240 ° C. for 7 hours, followed by reaction under the same conditions as the amorphous polyester resin A except that the pressure was gradually reduced at 240 ° C. A non-crystalline polyester resin dispersion D was prepared under the same conditions as the non-crystalline polyester resin dispersion A. The volume average particle diameter D50v was 130 nm.

<Preparation of Amorphous Polyester Resin Dispersion E>
The copolycondensation reaction was carried out at 240 ° C. for 11 hours, followed by reaction under the same conditions as the amorphous polyester resin A except that the pressure was gradually reduced at 240 ° C. A non-crystalline polyester resin dispersion E was synthesized under the same conditions as the non-crystalline polyester resin dispersion A. The volume average particle diameter D50v is 132 nm.

<Preparation of Amorphous Polyester Resin Dispersion F>
The copolycondensation reaction was carried out at 210 ° C. for 3 hours, followed by reaction under the same conditions as the non-crystalline polyester resin A except that the pressure was gradually reduced at 210 ° C. to produce a non-crystalline weight average molecular weight of 22,000. A non-crystalline polyester resin dispersion F was prepared under the same conditions as the non-crystalline polyester resin dispersion A. The volume average particle diameter D50v was 115 nm.

<Preparation of amorphous polyester resin dispersion G>
The copolycondensation reaction was carried out under the same conditions as those for the non-crystalline polyester resin A except that the copolycondensation reaction was carried out at 210 ° C for 4.5 hours and then gradually reduced in pressure at 210 ° C, and the weight average molecular weight was 31,000. An amorphous polyester resin G was synthesized, and an amorphous polyester resin dispersion G was produced under the same conditions as the amorphous polyester resin dispersion A. The volume average particle diameter D50v was 118 nm.

<Preparation of amorphous polyester resin dispersion H>
The copolycondensation reaction was carried out at 210 ° C. for 8 hours, followed by reaction under the same conditions as the non-crystalline polyester resin A except that the pressure was gradually reduced at 210 ° C. A non-crystalline polyester resin dispersion H was synthesized under the same conditions as the non-crystalline polyester resin dispersion A. The volume average particle diameter D50v is 122 nm.

<Preparation of styrene-containing resin dispersion>
82 parts by weight of styrene, 18 parts by weight of n-butyl acrylate, 2 parts by weight of methacrylic acid, 1 part by weight of n-dodecyl mercaptan and 2 parts by weight of a nonionic surfactant (manufactured by Sanyo Chemical Industries, Ltd., Nonibol 400) , And anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen R) 3 parts by weight in a reaction kettle dissolved in 510 parts by weight of ion-exchanged water. 50 parts by weight of ion-exchanged water in which parts by weight were dissolved was added. Thereafter, the reaction kettle was purged with nitrogen, and then the kettle was heated to 70 ° C. and emulsion polymerization was continued for 5 hours. As a result, a styrene-containing resin dispersion having a solid content of 20% and a volume average particle size of 201 nm was obtained.

<Preparation of Colorant Dispersion A>
C. I. 46 parts by weight of Pigment Yellow 74 (Daiichi Seika Kogyo Co., Ltd .: Seika Fast Yellow 2054), 4 parts by weight of an anionic surfactant (Dow Chemical Co., Dow Fax), and 200 parts by weight of ion-exchanged water are mixed and dissolved. Then, the mixture was dispersed for 10 minutes with a homogenizer (Ultra Tarrax manufactured by IKA) and then dispersed with an optimizer to obtain a colorant dispersion A having a volume average particle size of 145 nm and a solid content of 20% by weight.

<Preparation of Colorant Dispersion B>
The colorant is C.I. I. A colorant dispersion B having a volume average particle size of 140 nm and a solid content of 20% by weight was obtained in the same manner as in the preparation of the colorant dispersion A except that the pigment yellow 17 was changed to CI Pigment Yellow 17 (manufactured by DIC Corporation: KET Yellow 403). .

<Preparation of Colorant Dispersion C>
The colorant is C.I. I. A colorant dispersion C having a volume average particle size of 145 nm and a solid content of 20% by weight was obtained in the same manner as in the preparation of the colorant dispersion A, except that the pigment yellow 185 (Paliotol Yellow d1155, manufactured by BASF) was used.

<Preparation of Colorant Dispersion D>
The colorant is C.I. I. A colorant dispersion having a volume average particle size of 125 nm and a solid content of 20% by weight is the same as the preparation of the colorant dispersion A except that the pigment red 122 is changed to CI Pigment Red 122 (manufactured by Dainichi Seika Kogyo Co., Ltd .: Chromofine Magenta 6887). D was obtained.

<Preparation of Colorant Dispersion E>
The colorant is C.I. I. Pigment Blue 15: 3 (manufactured by Dainichi Seika Kogyo Co., Ltd .: Cyanine Blue 4937) Similar to the preparation of the colorant dispersion A, the colorant dispersion having a volume average particle size of 120 nm and a solid content of 20% by weight Liquid E was obtained.

<Preparation of Colorant Dispersion Liquid F>
A colorant dispersion F having a volume average particle size of 120 nm and a solid content of 20% by weight was obtained in the same manner as in the preparation of the colorant dispersion A except that the colorant was changed to carbon black (manufactured by Cabot: BPL).

<Preparation of release agent dispersion A>
Mixing 50 parts by weight of Fischer-Tropsch wax (manufactured by Nippon Seiwa Co., Ltd., FT-100), 1 part by weight of an anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK), and 200 parts by weight of ion-exchanged water Then, after heating to 95 ° C. and dispersing using a homogenizer (manufactured by IKA, Ultra Tarrax T50), a dispersion treatment for 360 minutes with a Manton Gorin high-pressure homogenizer (Gorin), a volume average particle size of 230 nm, A release agent dispersion A having a solid content of 20% by weight was obtained.

<Preparation of release agent dispersion B>
Release agent dispersion B having a volume average particle size of 210 nm and a solid content of 20% by weight, in the same manner as the preparation of release agent dispersion A, except that it is changed to paraffin wax (Nippon Seiwa Co., Ltd .: HNP-9). Got.

<Preparation of silica dispersion>
Silica sol (manufactured by Nissan Chemical Industries, Ltd .: Snowtex: solid content 20%) was used as it was.

<Preparation of titania dispersion>
A titania dispersion having a volume average particle size of 260 nm and a solid content of 20% by weight was obtained in the same manner as in the preparation of the colorant dispersion A except that rutile titanium oxide (R-680, manufactured by Ishihara Sangyo Co., Ltd.) was used. .

<Preparation of alumina dispersion>
An alumina dispersion having a volume average particle size of 600 nm and a solid content of 20% by weight was obtained in the same manner as in the preparation of the colorant dispersion A except that alumina (manufactured by Showa Denko KK: AL160SG-3) was used.

<Preparation of Plastic Compound Dispersion A>
A plastic compound dispersion having a volume average particle size of 210 nm and a solid content of 20% by weight, in the same manner as the preparation of the release agent dispersion A, except that it is changed to a higher fatty acid ester compound (Riken Vitamin Co., Ltd .: Poem DS-100A) A was obtained.

<Preparation of plastic compound dispersion B>
A plastic compound dispersion having a volume average particle size of 200 nm and a solid content of 20% by weight is the same as the preparation of the release agent dispersion A except that the higher alcohol compound (Nikko Chemicals Co., Ltd .: behenyl alcohol 65) is used. B was obtained.

<Preparation of plastic compound dispersion C>
The volume average particle size is 220 nm and the solid content is 20% by weight in the same manner as in the preparation of the release agent dispersion A except that the fatty acid metal soap (manufactured by NOF Corporation: Rapisol B-30, sodium dioctylsulfosuccinate) is used. A plastic compound dispersion C was obtained.

<Transparent toner production example 1>
Amorphous polyester resin dispersion A 210 parts by weight Release agent dispersion A 35 parts by weight

Ion exchange water was added to the above components so that the solid content was 16% by weight, and the mixture was sufficiently mixed and dispersed in a round stainless steel flask with an Ultra Turrax T50. Next, 0.8 parts by weight of polyaluminum chloride was added thereto, and the dispersion operation was continued with an ultra turrax. The flask was heated to 47 ° C. with stirring in an oil bath for heating. After maintaining at 47 ° C. for 60 minutes, 100 parts by weight of the amorphous polyester resin dispersion A was gradually added thereto. Thereafter, the pH of the system was adjusted to 9.0 with a 0.55 mol / L sodium hydroxide aqueous solution, and then the stainless steel flask was sealed, and heated to 90 ° C. while continuing stirring using a magnetic seal. Hold for 5 hours.
After completion of the above treatment, the mixture was cooled, filtered, sufficiently washed with ion exchange water, and then subjected to solid-liquid separation by Nutsche suction filtration. This was further redispersed in 3,000 parts by weight of ion-exchanged water at 40 ° C., and stirred and washed at 300 rpm for 15 minutes. This was repeated five more times, and when the pH of the filtrate was 7.01, the electrical conductivity was 9.7 μS / cm, and the surface tension was 71.2 Nm, solid-liquid separation was performed using No5A filter paper by Nutsche suction filtration. It was. Next, vacuum drying was continued for 12 hours to obtain toner mother particles.
Furthermore, 1.0 part by weight of hydrophobic silica (TS720: manufactured by Cabot) and 2.0 parts by weight of hydrophobic silica (X24: manufactured by Shin-Etsu Chemical Co., Ltd.) with respect to 100 parts by weight of the prepared toner base particles. Then, the mixture was mixed with a Henschel mixer at a peripheral speed of 25 m / sec for 3 minutes to obtain a transparent toner 1. This was weighed so that the toner concentration would be 5% by weight with respect to a ferrite carrier having a volume average particle diameter of 50 μm coated with 1% of polymethyl methacrylate (manufactured by Soken Chemical Co., Ltd .: weight average molecular weight 90000), and then ball milled for 5 minutes. A transparent toner developer 1 was prepared by stirring and mixing.

<Transparent toner production example 2>
Transparent toner 2 and transparent toner developer 2 were prepared in the same manner as in transparent toner production example 1, except that amorphous polyester resin dispersion B was used instead of amorphous polyester resin dispersion A.

<Transparent toner production example 3>
A transparent toner 3 and a transparent toner developer 3 were prepared in the same manner as in the transparent toner production example 1 except that the amorphous polyester resin dispersion C was used instead of the amorphous polyester resin dispersion A.

<Transparent toner production example 4>
A transparent toner 4 and a transparent toner developer 4 were prepared in the same manner as in the transparent toner production example 1 except that the amorphous polyester resin dispersion D was used instead of the amorphous polyester resin dispersion A.

<Transparent toner production example 5>
Transparent toner 5 and transparent toner developer 5 were prepared in the same manner as in transparent toner production example 1, except that amorphous polyester resin dispersion E was used instead of amorphous polyester resin dispersion A.

<Transparent Toner Production Examples 6 to 10>
In the transparent toners 1 to 5, the transparent toners 6 to 10 were prepared in the same manner as the transparent toners 1 to 5 except that 210 parts of each amorphous polyester resin dispersion liquid was 205 parts and 5 parts of silica dispersion liquid was further added. Transparent toner developers 6 to 10 were prepared.

<Transparent Toner Production Examples 11-15>
Transparent toners 11 to 15 and transparent toner developers 11 to 15 were prepared in the same manner as the transparent toners 6 to 10 except that in the transparent toners 6 to 10, the silica dispersion was changed to a titania dispersion.

<Transparent Toner Production Examples 16 to 20>
Transparent toners 16 to 20 and transparent toner developers 16 to 20 were prepared in the same manner as the transparent toners 6 to 10 except that the silica dispersion in the transparent toners 6 to 10 was changed to an alumina dispersion.

<Transparent Toner Production Examples 21 to 25>
In transparent toners 1-5, the same procedure as in transparent toners 1-5, except that 210 parts of each non-crystalline polyester resin dispersion was 209.5 parts and 0.5 part of colorant dispersion A was added. Transparent toners 21 to 25 and transparent toner developers 21 to 25 were prepared.

<Transparent Toner Production Examples 26-30>
Transparent toners 26 to 30 and transparent toner developers 26 to 30 were prepared in the same manner as the transparent toners 21 to 25 except that the colorant dispersion A was changed to the colorant dispersion B in the transparent toners 21 to 25.

<Transparent Toner Production Examples 31-35>
Transparent toners 31 to 35 and transparent toner developers 31 to 35 were prepared in the same manner as the transparent toners 21 to 25 except that the colorant dispersion A was changed to the colorant dispersion C in the transparent toners 21 to 25.

<Yellow toner production example 1>
Amorphous polyester resin dispersion F 187 parts by weight Colorant dispersion A 35 parts by weight Release agent dispersion A 35 parts by weight The amount of polyaluminum chloride used in the above materials is 0.6 parts by weight. A yellow toner 1 and a yellow toner developer 1 were obtained in the same manner as the transparent toner 1 except that the liquid was changed to an amorphous polyester resin dispersion F.

<Yellow toner production example 2>
A yellow toner 2 and a yellow toner developer 2 were prepared in the same manner as in the yellow toner production example 1 except that the amorphous polyester resin dispersion G was used in place of the amorphous polyester resin dispersion F.

<Yellow toner production example 3>
A yellow toner 3 and a yellow toner developer 3 were prepared in the same manner as in the yellow toner production example 1 except that the amorphous polyester resin dispersion H was used in place of the amorphous polyester resin dispersion F.

<Yellow Toner Production Examples 4 to 6>
In yellow toners 1 to 3, yellow toners 4 to 4 were prepared in the same manner as yellow toners 1 to 3 except that 187 parts of each amorphous polyester resin dispersion liquid was changed to 185 parts and 2.5 parts of plastic compound dispersion liquid A was further added. 6. Yellow toner developers 4 to 6 were prepared.

<Yellow toner production example 7>
A yellow toner 7 and a yellow toner developer 7 were prepared in the same manner as in the yellow toner production example 4 except that the plastic compound dispersion B was used in place of the plastic compound dispersion A.

<Yellow Toner Production Example 8>
A yellow toner 8 and a yellow toner developer 8 were prepared in the same manner as in the yellow toner production example 4 except that the plastic compound dispersion C was used in place of the plastic compound dispersion A.

<Yellow Toner Production Example 9>
A yellow toner 9 and a yellow toner developer 9 were prepared in the same manner as in the yellow toner production example 4 except that the release agent dispersion B was used instead of the release agent dispersion A.

<Magenta toner production example 1>
Magenta toner 1 and magenta toner developer 1 were prepared in the same manner as in yellow toner production example 4 except that colorant dispersion D was used instead of colorant dispersion A.

<Cyan toner production example 1>
Cyan toner 1 and cyan toner developer 1 were prepared in the same manner as in yellow toner production example 4 except that colorant dispersion E was used instead of colorant dispersion A.

<Black toner production example 1>
A black toner 1 and a black toner developer 1 were prepared in the same manner as in the yellow toner production example 4 except that the colorant dispersion F was used instead of the colorant dispersion A.

<Example>
Images were formed in combinations as shown in Table 1 using developers including transparent toners 1 to 35, yellow toners 1 to 9, magenta toner 1, cyan toner 1, and black toner 1, and the following evaluations were performed. . The results are shown in Table 1.

<Create image>
The developer thus obtained is filled into a developer of a DocuCentre-III C7600 modified machine (five tandem modified machine for double-sided printing) manufactured by Fuji Xerox Co., Ltd., which is a 5-drum tandem system, and recording paper (OK top coat + paper) In the case where the uppermost layer is a transparent toner, the lower layer is one of a yellow toner, a magenta toner, and a cyan toner at a fixing temperature of 160.degree. The toner applied amount is 4.0 g / m ² , the toner applied amount is 8.0 g / m ^{2 in} the case of two types of toner, and the toner applied amount is 12.0 g / m ^{2 in} the case of three types of toner. A solid image (18 cm × 27 cm) was formed.

<Formation of pressure bonding varnish layer>
A UV curable varnish (Dicure Clear UV1450HB DIC Co., Ltd.) was applied over the entire surface of the image paper with a bar coater at a coating amount of 6 g / m ² , and a conveyor type ultraviolet irradiation machine (high pressure mercury lamp 80 W / cm ² ). Then, ultraviolet irradiation was performed at a conveyor speed at which the integrated light amount was 60 mJ / cm ² to obtain a pseudo-adhesive sheet having a cured coating surface.
The resulting pseudo-adhesive sheet is tri-folded with a dry sealer (model 6860, manufactured by Toppan Forms Co., Ltd.), cut into a size where the postcard size is connected to the trilobe, and then Z-folded so that the pseudo-adhesive layers face each other. Then, it was passed through a press roll having a roll gap of 240 μm and pressure-bonded to produce a confidential postcard. The obtained confidential postcard was stored at room temperature for 1 month, and the tensile strength by T-peeling (a method of peeling to T-shape from both sides) was measured according to JAPAN TAPPI paper pulp test method No19-1: 2000. did. The following evaluation was performed and this was taken as peelability evaluation.

<Peelability>
As the evaluation method of peelability, evaluation was performed according to the following.
5: The problem of peelability cannot be confirmed.
4: Slight gloss unevenness can be confirmed on the peeled surface.
3: Although there is uneven gloss on the peeled surface, there is no practical problem.
2: Although there is uneven gloss on the peeled surface, the substrate is not destroyed.
1: A part of the base material on the peeling surface is broken.

<Adhesion>
Adhesiveness is sufficiently adhered, and even if folded, the adhesion part does not peel off, and the adhesion surface does not peel off. Also, the peelability indicates whether the sheet peels between the pseudo-adhesive layers without tearing. A five-step evaluation was performed. Practically 2 or more is necessary.
5: Adhesion problem cannot be confirmed.
4: Adhesiveness is slightly weak, and slight peeling is confirmed at the bent portion.
3: Adhesiveness is slightly weak, but there is a problem of peeling to the extent that there is no practical problem at the bent portion.
2: Adhesiveness is slightly weak, and some peeling is seen in addition to the bent part.
1: There is a problem in adhesion, and peeling is apparently occurring.

  The results are summarized in Tables 1 to 3.

1 Addressing surface of tri-fold crimped postcard paper 2 Printing surface 2 'Printing surface 3 Non-printing surface 3' Non-printing surface 4 Back surface of tri-folding postcard paper

Claims (6)

Forming an image layer with a colored toner containing a binder resin and a colorant on a support;
Forming a transparent layer on the image layer with a transparent toner containing a binder resin and a release agent; and
Including a step of forming a peelable pressure-bonding layer on the transparent layer,
The image forming method, wherein the transparent layer has a hardness greater than that of the image layer.   The image forming method according to claim 1, wherein the hardness is a hardness based on an atomic force microscope (AFM) measurement.   The image forming method according to claim 1, wherein the transparent toner contains Fischer-Tropsch wax as a release agent.   The image forming method according to claim 1, wherein the pressure-bonding layer is a pressure-bonding layer obtained by curing an ultraviolet curable composition.   The image forming method according to claim 1, wherein the pressure-bonding layer is a pressure-bonding layer obtained by curing an ultraviolet curable composition containing an ethylenically unsaturated compound, a photopolymerization initiator, and a filler.   A method for producing a pressure-bonded postcard, further comprising a step of pressure bonding the pressure-bonded layers formed by the image forming method according to claim 1.

Images