JP2021033149A - Image forming method - Google Patents

Abstract

To provide an image forming method that can form an image that is excellent in color metallic feel representing the color of a grounding resin image layer, while having metallic glossiness in powder decoration.SOLUTION: An image forming method of the present invention is an image forming method of supplying powder particles to a resin image layer formed on a recording medium to fasten the powder particles, and the average surface coverage by the powder particles fastened to a surface of the resin image layer is 30% or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to an image forming method, and more particularly to an image forming method capable of forming an image having a metallic luster and an excellent color metallic feeling expressing the color of the underlying resin image layer in powder decoration.

In recent years, the demand for decorative printing and high value-added printing has been increasing in the on-demand printing market. Among them, the demand for metallic printing is particularly large, and a wide variety of studies have been conducted. Here, metallic printing refers to printing an image having a metallic luster.
As one of the methods, a method of transferring a metal foil or a resin foil by using a toner image has been studied. For example, Patent Document 1 proposes a method of forming a toner image and adhering a transfer foil only to the toner portion. This method has a problem that when the foil is transferred to only a part of the image, all the remaining transfer foils are wasted.

On the other hand, studies have also been conducted on metallic toners in which a bright pigment is added to the toner. For example, Patent Document 2 proposes a method of forming a metallic image only in a necessary portion by incorporating a bright pigment in the toner. However, this method does not reach the required metallic feeling.

Therefore, a technique has been proposed in which powder particles are adhered to the image surface to give a metallic feeling for the purpose of forming an image having a high metallic feeling in a necessary portion without waste. For example, in Patent Document 3, the toner image is heated to soften the toner to generate an adhesive force (adhesive force), and the adhesive force is used to bond and fix the powder particles to express a metallic feeling. Has been proposed.
However, in this method, since the powder particles cover the image surface, the characteristics of the metallic powder particles are expressed as they are. Therefore, when it is desired to express a color metallic feeling, it is necessary to select powder particles that develop a desired color.

Japanese Unexamined Patent Publication No. 01-200985 Japanese Unexamined Patent Publication No. 2014-157249 Japanese Unexamined Patent Publication No. 2013-178452

The present invention has been made in view of the above problems and situations, and the problem to be solved is to have a color metallic feeling that expresses the color of the underlying resin image layer while having a metallic luster in powder decoration. The purpose of the present invention is to provide an image forming method capable of forming an excellent image.

In order to solve the above problems, the present inventor sets the surface average coverage of the powder particles fixed to the surface of the resin image layer within a specific range in the process of examining the cause of the above problems, thereby making the metal. It has been found that in the case of powder particles having a glossy feeling, it is possible to provide an image forming method capable of expressing a metallic luster feeling and forming an image having an excellent color metallic feeling in which the underlying color is expressed. The present invention has been reached.
That is, the above-mentioned problem according to the present invention is solved by the following means.

1. 1. An image forming method in which powder particles are supplied and fixed to a resin image layer formed on a recording medium.
An image forming method characterized in that the surface average coverage of the powder particles fixed to the surface of the resin image layer is 30% or less.

2. The surface average coverage of the powder particles fixed to the surface of the resin image layer is 20% or less, and
The image according to item 1, wherein the average exposure amount of each powder particle fixed to the surface of the resin image layer from the resin image layer is in the range of more than 0% and 10% or less. Forming method.

3. 3. The image forming method according to item 1 or 2, wherein the resin image layer is a color toner image layer formed by an electrophotographic method.

4. The image forming method according to any one of items 1 to 3, wherein the powder particles are flat.

5. Any of the items 1 to 4, wherein the average major axis of the powder particles is in the range of 5 to 500 μm and the average thickness is in the range of 0.2 to 5.0 μm. The image forming method according to item 1.

6. The image forming method according to any one of items 1 to 5, wherein the powder particles contain at least a metal and a metal oxide.

By the above means of the present invention, it is possible to express a metallic luster in powder decoration and to form an image having an excellent color metallic feeling in which the underlying color is expressed.
According to the means of the present invention, when powder particles having no metallic luster are used, the color of the powder particles is not impaired, and the surface shape of the powder particles is processed to obtain an interference color. Even in the case of the powder particles provided, the effect of not impairing the decorativeness can be obtained, and the color of the underlying resin image layer can also be expressed.
Although the mechanism of expression or mechanism of action of the effect of the present invention has not been clarified, it is inferred as follows.
In general, the larger the particle size of the powder particles, the larger the area that reflects light, the higher the reflectance, and the higher the metallic luster can be obtained. Further, by not covering the powder particles with the resin image layer, the amount of reflection is not reduced and the metallic luster can be maintained. However, in such a configuration, the metallic luster is too high, so that only the inherent luster of the powder particles is exhibited.
Therefore, in the present invention, the surface average coverage of the powder particles fixed to the surface of the resin image layer is set to 30% or less so that the powder particles are not exposed more than a certain amount, that is, the surface of the resin image layer. By exposing the powder particles to only a part of the particles, it is possible to have a metallic luster and a color metallic feeling that also expresses the color of the underlying resin image layer.

Schematic diagram for explaining the image forming method of the present invention Schematic diagram for explaining the method of calculating the exposure amount of powder particles according to the present invention. Schematic diagram for explaining the exposure of powder particles according to the present invention. Schematic diagram for explaining the exposure of powder particles according to the present invention. Schematic diagram for explaining the major axis, minor axis and thickness of the powder particles according to the present invention. Schematic diagram for explaining the image forming method of the present invention Schematic diagram for explaining the fixed state of conventional powder particles

The image forming method of the present invention is an image forming method in which powder particles are supplied and fixed to a resin image layer formed on a recording medium, and the powder particles are fixed to the surface of the resin image layer. The surface average coverage is 30% or less.
This feature is a technical feature common to or corresponding to each of the following embodiments.

In an embodiment of the present invention, the surface average coverage of the powder particles adhered to the surface of the resin image layer is 20% or less, and each powder particle adhered to the surface of the resin image layer. It is preferable that the average exposure amount from the resin image layer is in the range of 10% or less, which is larger than 0%, from the viewpoint of excellent metallic luster and color metallic feeling.

Further, it is preferable that the resin image layer is a color toner image layer formed by an electrophotographic method in that the effect of the present invention can be remarkably exhibited.

It is preferable that the powder particles are flat in that a desired decorative image can be obtained by controlling the orientation of the powder particles.

It is preferable that the average major axis of the powder particles is in the range of 5 to 500 μm and the average thickness is in the range of 0.2 to 5.0 μm. By setting the major axis within the above range, a high metallic luster can be exhibited, and the powder particles do not come off when the image is rubbed. Further, by setting the thickness within the above range, the plane direction of the powder particles including the major axis and minor axis directions of the powder particles fixed to the surface of the resin image layer is substantially the surface direction of the resin image layer. A good alignment state of the powder particles along the target is sufficiently formed, and the powder particles do not come off when the image is rubbed.

It is preferable that the powder particles contain at least a metal and a metal oxide in that a high metallic luster can be exhibited.

Hereinafter, the present invention, its constituent elements, and modes and modes for carrying out the present invention will be described. In the present application, "~" is used to mean that the numerical values described before and after the value are included as the lower limit value and the upper limit value.

[Outline of the image forming method of the present invention]
The image forming method of the present invention is an image forming method in which powder particles are supplied and fixed to a resin image layer formed on a recording medium, and the powder particles are fixed to the surface of the resin image layer. The surface average coverage is 30% or less.

That is, in a photograph obtained by observing and taking a cross section of the resin image layer according to the present invention with a scanning electron microscope, the surface average of the resin image layer is obtained by the powder particles fixed to the first layer including the surface of the resin image layer. The coverage is 30% or less. The powder particles are fixed to the first layer or fixed to the inside of the resin image layer so that the surface average coverage is 30% or less. Specifically, as shown in FIG. 1 (c), all the powder particles 101 may be fixed to the first layer S1 to have a one-layer structure, or FIGS. 1 (a) and 1 (b). As shown in the above, the powder particles 101 may be fixed to the first layer S1 and the second layer S2 adjacent to the first layer S1 to have a two-layer structure, but the one-layer structure is required. Is preferable because it has a metallic luster and is excellent in color metallic feeling.
The portion where the two powder particles appear to overlap is one layer when the gap between the powder particles is less than the thickness of the powder particles.

In order to reduce the surface average coverage of the powder particles fixed to the surface of the resin image layer to 30% or less, as will be described later, when the powder particles are supplied to the resin image layer, the powder particles are supplied. It is preferable that the resin image layer is melted or softened to the extent that powder particles adhere to it, and the heating temperature for the resin image layer, the amount of powder particles supplied to the resin image layer, and the powder supplied to the resin image layer. The rubbing speed and rubbing time when rubbing and fixing the body particles, and the additional heating frequency, additional heating temperature and additional heating when the resin image layer and powder particles are additionally heated after rubbing and fixing. It is preferable to control the transport speed.
In particular, by additional heating after the rubbing / fixing step, the toner can seep out from the gaps between the powder particles to the surface and cover a part of the powder particles, so that the surface average coverage can be easily adjusted.
Further, by performing a reprinting step after the additional heating step, the surface average coverage can be adjusted by coating a part of the powder particles with a resin. When the surface average coverage is adjusted by performing the reprinting step, the additional heating step may or may not be performed. Similarly, the surface average coverage can be adjusted when additional heating is performed before and after the reprinting process.

<Surface average coverage>
The surface average coverage means the surface average coverage of the powder particles with respect to the decorative region (the region to which the powder particles are to be adhered).
Specifically, the surface average coverage was taken at a magnification of 100 times with a digital microscope VHX-6000 manufactured by KEYENCE for 10 fields of view at random, and binarized with LUSEX-AP manufactured by Nireco Corporation. Then, each coverage ratio in 10 fields of view is obtained by the following formula, and the average of these is adopted.
Surface average coverage = (area when viewed from above the powder particles exposed from the surface of the resin image layer) / (area of the surface of the resin image layer) × 100
It is preferable that the portion coated with the powder particles and the portion not coated are uniformly dispersed.

In the present invention, it is preferable that the resin image layer is in a fixed state in which the distance between the powder particles is observed in a state of being substantially uniformly dispersed. Such a fixed state can prevent the powder particles from coming off. In addition, the surface of the resin image layer can be prevented from being disturbed, and the image quality can be improved.

Further, as shown in FIG. 7A, when the powder particles 101 are not arranged parallel to the surface of the resin image layer 102, the powder particles 101 adhering diagonally give a metallic luster. However, the powder particles 101 are likely to come off, and the surface of the resin image layer 102 is disturbed, resulting in deterioration of image quality.
Further, as shown in FIG. 7B, when the powder particles 101 are completely embedded in the resin image layer 102, the color of the underlying resin image layer 102 is expressed, but the metallic luster is felt. It is not preferable because it will decrease.

In particular, in the present invention, the surface average coverage of the powder particles adhered to the surface of the resin image layer is 20% or less, and the powder particles adhered to the surface of the resin image layer are said to have the same surface average coverage. It is preferable that the average exposure amount from the resin image layer is in the range of 10% or less, which is larger than 0%, because the color of the resin image layer can be expressed while maintaining the metallic luster, and the color metallic feeling is excellent. ..

In the present invention, "exposed from the resin image layer" means that only the surface of the powder particles is exposed and the surface and side surfaces of the powder particles are exposed in the image (two-dimensional image) observed with a scanning electron microscope. There are cases where it is done. In these cases, the exposure amount is calculated by the method shown below, and when the calculated exposure amount is larger than 0%, it is defined as "exposed from the resin image layer". Further, when the exposure amount is 0%, it is assumed that "it is not exposed from the resin image layer".

<Calculation of exposure amount of powder particles>
(Cross section observation method)
After cutting out a powder decorative image in which powder particles are fixed on the surface of the resin image layer and solidifying and embedding it with an embedding resin, the cutting sample is cut and the cut surface is ion milled by an ion milling apparatus. , Prepare a sample for cross-sectional observation.
For example, an observation sample is observed with an ultra-high resolution field emission scanning electron microscope (S-4800, manufactured by Hitachi High-Technologies Corporation) at a magnification at which 10 powder particles adhering to the resin image layer can be seen in one field of view. The observed image is binarized with LUSEX-AP manufactured by Nireco Corporation, and the exposure amount of each powder particle is calculated by the following method.

(Exposure amount)
Exposure = (perimeter of powder particles exposed from the resin image layer in the cross-sectional image) / (total circumference of the powder particles in the cross-sectional image) × 100
Perimeter of exposed powder particles (exposed perimeter): Perimeter of the part exposed from the resin image layer Overall circumference of powder particles: Length obtained by actually measuring the entire circumference of powder particles The exposed peripheral length is, for example, in the case of the powder particles 101A in FIG. 2, the length of the broken line portion (exposed upper surface + side surface length MA). Further, in the case of powder particles 101B, the length of the broken line portion (exposed upper surface + side surface length MB), and in the case of powder particles 101C, the length of the broken line portion (exposed upper surface + side surface length). MC).
For example, in the case of the powder 101A in FIG. 2, the total circumference is the sum (MA + mA) of the length of the broken line portion (MA) and the length of the solid line portion (mA). Further, in the case of the powder particles 101B, it is the sum (MB + mB) of the length (MB) of the broken line portion and the length (mB) of the solid line portion. In the case of powder particles (101C), it is the sum (MC + mC) of the length of the broken line portion (MC) and the length of the solid line portion (mC).

In the present invention, if the exposure amount calculated by the above method is larger than 0%, it is considered to be exposed. For example, as shown in FIG. 3, a part of the powder particles 101 fixed to the surface is a resin image layer. Even if it is covered with 102, it is considered as an exposed particle.
In particular, as shown in FIG. 4, only one surface of the upper surface of the powder particles 101 fixed to the surface is completely exposed, and the opposite surface (lower surface) and the surface in the thickness direction are completely buried in the resin image layer 102. Is preferable.

[Image formation method]
Hereinafter, the configuration of the image forming method of the present invention will be described.

<Recording medium>
The recording medium according to the present invention is not particularly limited, and for example, plain paper from thin paper to thick paper, high-quality paper, coated printing paper such as art paper or coated paper, commercially available Japanese paper, postcard paper, and the like. Papers; resin films such as polypropylene (PP) film, polyethylene terephthalate (PET) film, triacetyl cellulose (TAC) film; cloth, etc., but are not limited thereto. Further, the color of the recording medium is not particularly limited, and recording media of various colors can be used.

<Resin image layer>
The resin image layer is not particularly limited as long as it can adhere powder particles to the surface, and for example, it preferably contains a resin that softens or plasticizes by heating. Further, it is preferable that the resin image layer is a color toner image layer formed by an electrophotographic method because the effect of the present invention can be remarkably exhibited.
Examples of such a resin include a thermoplastic resin and a thermosetting resin. In addition to the thermoplastic resin, other components such as a colorant, a dispersant, a surfactant, a plasticizer, a mold release agent, and an antioxidant may be contained.

As the thermoplastic resin, a known resin having thermoplasticity can be used, and there is no particular limitation. Further, as the thermosetting resin, a known resin having a thermosetting property can be used, and the present invention is not particularly limited.

Examples of thermoplastic resins or heat-meltable resins include (meth) acrylic resins, styrene resins, styrene / acrylic resins, olefin resins (including cyclic olefin resins), polyester resins, polycarbonate resins, polyamide resins, and polyphenylene ethers. Resins, polyphenylene sulfide resins, halogen-containing resins (polyvinyl chloride, polyvinylidene chloride, fluororesins, etc.), polysulfone resins (polyethersulfone, polysulfone, etc.), cellulose derivatives (cellulose esters, cellulose carbamates, cellulose ethers, etc.) , Silicone resin (polydimethylsiloxane, polymethylphenylsiloxane, etc.), polyvinyl ester resin (polyvinyl acetate, etc.), acrylonitrile-butadiene-styrene copolymer (ABS resin), polyvinyl alcohol resin and derivative resins thereof, rubber or elastomer (Diene rubbers such as polybutadiene and polyisoprene, styrene-butadiene copolymers, acrylonitrile-butadiene copolymers, acrylic rubbers, urethane rubbers, etc.) and the like. The thermoplastic resin and the thermosetting resin can be used alone or in combination of two or more. In addition, in this specification, "(meth) acrylic" means "acrylic and / or methacrylic".

The thermoplastic resin and the thermosetting resin may be copolymers. When the thermoplastic resin is a copolymer, the form of the copolymer may be any of a block copolymer, a random copolymer, a graft copolymer, and an alternating copolymer.

Further, as the thermoplastic resin and the thermosetting resin, a synthetic product or a commercially available product may be used. The polymerization method for synthesizing these thermoplastic resins and thermosetting resins is not particularly limited, and known methods can be used. For example, a high-pressure radical polymerization method, a medium-low pressure polymerization method, a solution polymerization method, a slurry polymerization method, a massive polymerization method, an emulsion polymerization method, a gas phase polymerization method and the like can be mentioned. Further, the radical polymerization initiator and the catalyst used at the time of polymerization are not particularly limited, and for example, radical polymerization initiators such as azo-based or diazo-based polymerization initiators and peroxide-based polymerization initiators; peroxide catalysts and Cheegler-Natta. Polymerization catalysts such as catalysts and metallocene catalysts; etc. can be used.

From the viewpoint that the surface state of the resin image layer can be easily controlled, the thermoplastic resin and the heat-meltable resin consist of a group consisting of (meth) acrylic resin, styrene resin, styrene / acrylic resin, and polyester resin among the above-mentioned resins. It is preferable to contain at least one selected, and it is more preferable to contain at least one selected from the group consisting of styrene / acrylic resin and polyester resin.

The styrene / acrylic resin referred to in the present invention is formed by polymerizing at least a styrene monomer and a (meth) acrylic acid ester monomer. Here, the styrene monomer includes not only styrene _{represented by the structural formula of CH 2} = CH-C ₆ H ₅ but also a structure having a known side chain or functional group in the styrene structure.

The (meth) acrylic acid ester monomer has a functional group having an ester bond in the side chain. _{Specifically,} CH 2 = CHCOOR (R is an alkyl group) other acrylic acid ester monomer represented _by, methacrylic acid ester represented by _{CH 2 = C (CH 3)} COOR (R is an alkyl group) Contains vinyl esters such as monomers.

In addition to the above-mentioned copolymers formed only of the styrene monomer and the (meth) acrylic acid ester monomer, the styrene / acrylic resin includes general vinyl monomers (olefins and vinyl esters). , Vinyl ethers, vinyl ketones, N-vinyl compounds, etc.) are also included.

Further, the styrene / acrylic resin includes a styrene monomer, a (meth) acrylic acid ester monomer, and other general vinyl monomers, as well as a polyfunctional vinyl monomer and an ionic dissociation in the side chain. Copolymers formed using a vinyl monomer having a group (carboxy group, sulfonic acid group, phosphoric acid group, etc.) are also included. Examples of such vinyl monomers include acrylic acid, methacrylic acid, maleic acid, itaconic acid and the like.

The polyester resin is a known polyester resin obtained by a polycondensation reaction between a divalent or higher carboxylic acid (polyvalent carboxylic acid component) and a divalent or higher alcohol (polyhydric alcohol component). The polyester resin may be amorphous or crystalline.
The valences of the polyvalent carboxylic acid component and the polyhydric alcohol component are preferably 2 to 3 respectively, and particularly preferably 2 each. Therefore, as a particularly preferable form, the valences are 2 each (that is, dicarboxylic acid). Acid component, diol component) will be described.
Examples of the dicarboxylic acid component include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonandicarboxylic acid, and 1,10-decandicarboxylic acid. (Dodecanedioic acid), 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,1
Saturated aliphatic dicarboxylic acids such as 4-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid; methylenesuccinic acid, fumaric acid, maleic acid, 3-hexendioic acid, 3-octendio Unsaturated aliphatic dicarboxylic acids such as icic acid and dodecenyl succinic acid; phthalic acid, terephthalic acid, isophthalic acid, t-butylisophthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-phenylene diacetic acid, 2,6- Examples thereof include unsaturated aromatic dicarboxylic acids such as naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, and anthracenedicarboxylic acid; and these lower alkyl esters and acid anhydrides can also be used. The dicarboxylic acid component may be used alone or in combination of two or more.

In addition, trimellitic acid, pyromellitic acid and other trivalent or higher valent carboxylic acids, anhydrides of the above carboxylic acid compounds, alkyl esters having 1 to 3 carbon atoms and the like can also be used.

Examples of the diol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 1,7-heptane. Diol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecane Saturated aliphatic diols such as diols, 1,18-octadecanediols, 1,20-eicosanediols, neopentyl glycols; 2-butene-1,4-diols, 3-butene-1,4-diols, 2-butins. Unsaturated aliphatic diols such as -1,4-diol, 3-butin-1,4-diol, 9-octadecene-7,12-diol; bisphenols such as bisphenol A and bisphenol F, and addition of ethylene oxide thereof. Examples thereof include aromatic diols such as alkylene oxide adducts of bisphenols such as propylene oxide adducts, and derivatives thereof can also be used. The diol component may be used alone or in combination of two or more.
The method for producing the polyester resin is not particularly limited, and examples thereof include a method of polycondensing (esterifying) the polyvalent carboxylic acid component and the polyhydric alcohol component using a known esterification catalyst.

The weight average molecular weight of the resin contained in the resin image layer is not particularly limited, but is preferably 2000 to 1000000, more preferably 5000 to 100000, and particularly preferably in the range of 1000 to 50000.

(Weight average molecular weight (Mw), number average molecular weight (Mn))
The resin to be measured is dissolved in tetrahydrofuran (THF) to a concentration of 1 mg / mL, then filtered using a membrane filter having a pore size of 0.2 μm, and the obtained solution is used as a sample for GPC measurement. There was. As the GPC measurement conditions, the GPC analysis conditions shown below were adopted, and the weight average molecular weight or the number average molecular weight of the resin contained in the sample was measured.

<GPC measurement conditions>
"HLC-8120GPC, SC-8020 (manufactured by Tosoh Corporation)" is used as the GPC device, two "TSKgel, SuperHM-H (manufactured by Tosoh Corporation 6.0 mm ID x 15 cm)" are used as the column, and tetrahydrofuran is used as the eluent. (THF) was used. The analysis was performed using a flow rate of 0.6 mL / min, a sample injection volume of 10 μL, a measurement temperature of 40 ° C., and an RI detector. The calibration curve is "polystylene standard sample TSK standard" manufactured by Tosoh Corporation: "A-500", "F-1", "F-10", "F-80", "F-380", "A-2500". , "F-4", "F-40", "F-128", "F"
It was prepared from 10 samples of "-700". The data collection interval in the sample analysis was set to 300 ms.

The content of the resin in the resin image layer is not particularly limited, but is 0 with respect to the total mass of the resin image layer from the viewpoint of softening the surface of the resin image layer and making it easier to control the surface state of the resin image layer. It is preferably in the range of more than mass% and 95% by mass or less, more preferably in the range of more than 0% by mass and 50% by mass or less, further preferably in the range of 5 to 50% by mass, and 10 to 50% by mass. It is particularly preferable that the range is.

On the other hand, when the resin image layer contains other components (for example, a colorant, a mold release agent, etc.) together with the resin, the content of the other components is not particularly limited, but the surface of the resin image layer is melted or softened. From the viewpoint of facilitating control of the surface state of the resin image layer, it is preferably 3 to 40% by mass, and more preferably 5 to 20% by mass with respect to the total mass of the resin image layer.

The colorant as the other component is not particularly limited, and known dyes and pigments can be used. Examples of such a colorant include carbon black, magnetic material, iron / titanium composite oxide black, and the like; I. Dyes such as Solvent Yellow 19 and 44; C.I. I. Pigments such as Pigment Yellow 14 and 17; C.I. I. Dyes such as Solvent Red 1, 49; C.I. I. Pigments such as Pigment Red 5 and 122; C.I. I. Dyes such as Solvent Blue 25 and 36; C.I. I. Pigment Blue 1 and Pigment Blue 7 and other pigments can be mentioned, but are not limited thereto.

The release agent as the other component is not particularly limited, and a known release agent can be used. Examples of such a release agent include polyolefin waxes such as polyethylene wax and polypropylene wax; branched chain hydrocarbon waxes such as microcrystallin wax; long chain hydrocarbon waxes such as paraffin wax and sazole wax; and distearyl ketones. Dialkylketone waxes such as carnauba wax, montan wax, behenyl behenate, trimethylpropantribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18 -Ester waxes such as octadecanediol distearate, tristearyl trimellitic acid, and distealyl maleate; amide waxes such as ethylenediaminebehenylamide and tristearylamide trimellitic acid are examples, but are not limited thereto.

The thickness of the resin image layer is not particularly limited, but is preferably in the range of 1 to 100 μm, more preferably in the range of 1 to 50 μm, for example. When the thickness of the resin image layer is within the above range, the orientation of the powder particles can be more easily controlled, and the texture can be easily adjusted.

<Powder particles>
In the image forming method of the present invention, the powder particles can be appropriately selected according to the purpose of decoration and the desired texture. Here, an aggregate of powder particles is referred to as powder, and the powder means a substance that remains in the state of powder even in the final image.

(Details of powder particles)
The shape and size of the powder particles supplied on the resin image layer are not particularly limited, and it is preferable to select an appropriate shape and size in order to achieve the desired texture.

From the viewpoint of shape, powder particles are roughly classified into spherical (spherical powder particles) and non-spherical (non-spherical powder particles).
Here, the "spherical powder particles" have an average circularity of 0.970 in their cross-sectional shape or projected shape.
The above powder particles (upper limit: 1.000). The average circularity can be obtained according to the "Waddell's formula". For example, the average circularity is a value measured using the following flow type particle image analyzer "FPIA-3000" (manufactured by Sysmex Corporation). May be good. Specifically, the powder is moistened with an aqueous surfactant solution, ultrasonically dispersed for 1 minute, dispersed, and then HPF is detected in the measurement condition HPF (high magnification imaging) mode using "FPIA-3000". The measurement is performed at an appropriate concentration of several 4,000 pieces. The circularity is calculated by the following formula.

Circularity = (peripheral length of a circle having the same projected area as the particle image) / (peripheral length of the particle projected image)
The average circularity is an arithmetic mean value obtained by adding the circularity of each particle and dividing by the total number of measured particles.
Therefore, "non-spherical powder particles" are powder particles other than spherical powder particles, and the average circularity of the cross-sectional shape or projected shape thereof is less than 0.970.

Above all, the shape of the powder particles is preferably non-spherical from the viewpoint of achieving the desired texture by controlling the orientation of the powder particles. That is, it is preferable that the powder particles include non-spherical powder particles. From the same viewpoint, it is more preferable that the non-spherical powder particles include flat powder particles (that is, powder particles having a flat shape).
Here, the "flat shape" or "flat shape" means, for example, as shown in FIGS. 5A and 5B, the maximum length of the powder particles 101 intersects the major axis L and the major axis L. When the maximum length in the direction is the minor axis l and the minimum length in the direction orthogonal to the major axis L is the thickness t, the ratio (l / t) of the minor axis l to the thickness t is 5 or more. It means that it has a certain shape. The terms "flat" and "flat" include, for example, shapes called flakes, scales, plates, flakes and the like.

The non-spherical powder particles preferably have an average major axis L in the range of 3 to 600 μm, preferably in the range of 5 to 500 μm, from the viewpoint of sufficiently exhibiting the appearance effect due to the oriented adhesion of the non-spherical powder particles. Is more preferable. By setting the average major axis to 3 μm or more, the reflection area becomes sufficient and a good metallic luster can be exhibited. On the other hand, by setting the average major axis to 600 μm or less, it is possible to prevent the powder particles from leaving the resin image layer when the image is rubbed.
Further, the non-spherical powder particles preferably have an average thickness t in the range of 0.1 to 10 μm, and more preferably in the range of 0.2 to 5 μm. By setting the average thickness to 0.1 μm or more, the plane direction of the non-spherical powder including the major axis direction and the minor axis direction of the non-spherical powder adhering to the surface of the resin image layer is the resin image layer. A good orientation of the non-spherical powder substantially along the surface direction of is sufficiently formed. On the other hand, by setting the average thickness to 10 μm or less, it is possible to prevent the powder particles from leaving the resin image layer when the image is rubbed.
Further, by setting the average major axis and the average thickness of the powder particles within the above ranges, the powder particles fall parallel to the surface of the resin image layer in the rubbing / fixing step, and the adhesive force is exhibited. Things will adhere and remain on the surface of the resin image layer.

The average thickness of the powder particles is an average value of thicknesses arbitrarily measured for 100 powder particles, and the average major axis of the powder particles is a major axis arbitrarily measured for 100 powder particles. Is the average value of. In addition, the thickness and particle size (including major axis and minor axis) of each powder particle are determined by sprinkling the powder particle on a double-sided tape to fix the powder particle, and using the microscope VHX-6000 to fix the surface of the powder particle. The observed image is binarized with LUSEX-AP manufactured by Nireco Co., Ltd., and the major axis L, minor axis l, and thickness t are arbitrarily determined for 100 powder particles. We will measure and adopt the average value.

The material of the powder particles is not particularly limited, and various materials such as resin, glass, metal, and metal oxide can be used. Above all, the powder particles preferably contain a metal or a metal oxide. When a metal or a metal oxide is contained, a desired metallic luster can be exhibited in an image having sufficient luster.

Further, the material constituting the powder particles may be one kind alone or two or more kinds. When the powder particles contain two or more kinds of materials, they may be in a form in which they are uniformly dispersed, or in a form in which another material is laminated (coated) on one material. May be good. As such a form, for example, a form in which a coating material (shell) made of a metal or a metal oxide is laminated on a base material (core) made of a resin, glass, or the like; a base material (core) made of a metal or a metal oxide. ) In a form in which a coating film (shell) made of resin, glass, or the like is laminated; and the like, but the present invention is not limited thereto.

The powder particles may be synthetic products or commercially available products. Examples of non-spherical powders include Metashine (registered trademark) (manufactured by Nippon Plate Glass Co., Ltd.), Sunshine Baby Chrome Powder, Aurora Powder, Pearl Powder (manufactured by GG Corporation), and ICEGEL Mirror Metal Powder (TAT Co., Ltd.). , Pika Ace (registered trademark) MC Shine Dust, Effect C (manufactured by Kurachi Co., Ltd.), Pregel (registered trademark) Magic Powder, Mirror Series (manufactured by Prianfa Co., Ltd.), Bonnail (registered trademark) Shine Powder (K's Plan Co., Ltd.) Ing), LG neo (registered trademark) (manufactured by Oike Kogyo Co., Ltd.) and the like. Examples of spherical powder include high-precision Unibeads (registered trademark) (manufactured by Unitika Ltd.), Finesphere (registered trademark) (manufactured by Nippon Electric Glass), and the like.

The powder particles supplied on the resin image layer may be only one type, or two or more types may be mixed and used.

The image forming method of the present invention includes a step of supplying powder particles to a resin image layer formed on a recording medium (powder supply step), a step of rubbing / fixing (rubbing / fixing step), and a step of rubbing / fixing. It has a step of additional heating (additional heating step) after the rubbing / fixing step.

(Powder supply process)
(1) The powder supply step is appropriately selected regardless of whether the powder particles are supplied in advance on the recording medium or the powder particles are supplied on the resin image layer formed on the recording medium. ..
The method for supplying the powder particles is not particularly limited, and as the powder supply means used in the powder supply step, a known device can be used depending on the properties of the powder. For example, the powder supply means described in Japanese Patent Application Laid-Open No. 2013-178452 (Patent Document 3 above) can be used as the powder supply means according to the present invention. Further, the powder supply means according to one embodiment of the present invention is a powder supply device 10 provided with a powder storage unit 11 for accommodating powder particles 101 and a powder supply roller 12 as shown in FIG. You may.

As a more specific example of the method of supplying powder particles, when the powder particles are insulating powder, the positively or negatively charged insulating powder particles are conductive from the powder accommodating portion 11. A method of supplying the insulating powder particles to the powder supply roller (conductive roller) 12 and supplying the insulating powder particles carried by the conductive roller onto the resin image layer can be mentioned. That is, when the powder particles are insulating powder particles, the powder supply device (powder supply means) 10 having the powder storage portion 11 and the conductive powder supply roller (conductive roller) 12 is provided. It is preferable to use it.

Further, as another specific example of the method of supplying powder particles, when the powder particles are magnetic powder particles, the magnetic powder particles are transferred from the powder storage unit 11 to a powder supply roller having magnetism. A method of supplying the particles to the (magnet roller) 12 and supplying the particles onto the magnetic powder resin image layer carried and conveyed by the magnet rollers can be mentioned. That is, when the powder particles are magnetic powder, a powder supply device (powder supply means) 10 having a powder storage portion 11 and a magnetic powder supply roller (magnet roller) 12 can be used. preferable.

The amount of powder particles supplied to the resin image layer is not particularly limited as long as it can express the desired texture, and is preferable due to the characteristics such as the material, shape, and specific gravity constituting the powder particles. Since the range is different, the amount is not particularly limited.

The powder particles may be selectively supplied only on the resin image layer, or may be supplied not only on the resin image layer but also on the entire surface of the recording medium including the portion where the resin image layer is not formed. You may.

Further, it is preferable to heat the resin image layer before or after the powder supply step or at the time of powder supply (heating step). By heating, the resin image layer is melted or softened, and the powder particles are easily fixed to the surface of the resin image layer.
Specifically, as shown in FIG. 6, it is preferable to use a heating roller 13, a heater (hot plate) 14, a pressure roller 17 used in the rubbing / fixing step described later, and the like.
The heating roller heats and melts the resin image layer while conveying the recording medium on which the resin image layer is formed as a means for melting and softening the resin image layer. The heating roller has a rotation axis in a direction perpendicular to the transport direction of the recording medium, and sandwiches and transports the recording medium together with an auxiliary roller (not shown) facing the heating roller. The heating roller has a built-in heat source (not shown) and heats and melts the resin image layer on the recording medium to make the resin image layer sticky. The heating roller is preferably covered with a heat insulating member.

The hot plate heats the recording medium in which the resin image layer is heated and melted. The hot plate is provided between the heating roller and the powder supply roller to heat the back surface of the recording medium. By heating the back surface of the recording medium, the temperature drop of the resin image layer on the recording medium is prevented, and the adhesiveness of the resin image layer is maintained.

The heating temperature of the resin image layer by the heating roller or hot plate should be in the range of 70 to 200 ° C., while maintaining the metallic luster, the powder particles adhere to the resin image layer with sufficient adhesive force to prevent detachment. It is preferable in that it can be prevented.
Here, as the heating means, a contact type heating roller, a hot plate, or the like has been mentioned, but the heating means is not limited to these, and a non-contact type heating means may be used. Examples of the non-contact heating means include a dryer, an infrared lamp, a visible light lamp, an ultraviolet lamp, a hot air oven, and the like.

(Rubbing / fixing process)
In the image forming method of the present invention, in addition to the above powder supply step, a rubbing / fixing step of rubbing the resin image layer to which the powder particles are supplied to fix the powder particles to the resin image layer is further performed. The inclusion means that the powder particles supplied to the surface of the resin image layer are fixed to the resin image layer to some extent, and the surface average coating with the powder particles fixed to the surface of the resin image layer by an additional heating step described later. It is preferable in that the rate can be controlled to 30% or less.

The rubbing / fixing step is a step of rubbing the resin image layer to which the powder particles are attached from above the powder particles to fix the powder particles, and is performed after the powder supply step. ..
Here, "rubbing" means that the rubbing means (rubbing member) moves relative to the resin image layer along the surface while contacting the surface of the resin image layer on the recording medium. To do. That is, it means applying a force in the direction perpendicular to the pressing force (parallel to the surface of the resin image layer) while pressing the resin image layer at the same time.

In the powder supply step, the resin image layer to which the powder particles are attached can be rubbed from above the powder particles to align the orientation of the powder particles with respect to the surface of the resin image layer. it can. More specifically, by rubbing, the angles of the powder particles with respect to the surface of the resin image layer are easily aligned, so that a metallic luster can be easily formed. In particular, when the powder is a flat powder, the flat surface is oriented along the surface of the resin image layer, so that a metallic luster is more easily formed.

Further, the above-mentioned "rubbing" preferably involves pressing the resin image layer (resin image layer to which powder particles are attached). That is, it is preferable that the rubbing / fixing step includes rubbing and pressing the resin image layer to which the powder particles are supplied. By pressing the resin image layer, a part of the powder particles is pushed into the resin image layer, so that the adhesion of the powder particles to the resin image layer can be strengthened. Therefore, the intensity of the finally formed glossy image can be improved.
Here, "pressing" means pressing the surface of the resin image layer in a direction intersecting with the surface of the resin image layer (for example, in a vertical direction).
In particular, in the present invention, the force in the pressing direction (direction intersecting the surface of the resin image layer (vertical direction)) is weak so that the powder particles are not completely buried in the resin image layer. However, it is preferable to fix the resin image layer so that a large amount of force is applied from the parallel direction to the surface of the resin image layer. As a result, the powder particles can be fixed to the relatively surface side of the resin image layer without being excessively embedded inside the resin image layer, and as a result, a color metallic feeling can be expressed.

The rubbing / fixing step is performed by rubbing the resin image layer to which the powder particles are attached by rubbing with a rubbing means. Specifically, in the rubbing / fixing step, the rubbing member as a rubbing means is brought into contact with the resin image layer to which the powder particles are attached, and the rubbing member is brought into contact with the resin image layer. This is done by moving them relatively. At this time, the direction in which the rubbing member is moved is not particularly limited, and may be only one direction, may be reciprocated, or may be in a plurality of directions. However, in order to easily control the orientation of the powder particles and to form a desired metallic luster, it is preferable that the sliding member moves in only one direction.

As described above, it is preferable to control the rubbing conditions for the purpose of expressing a metallic luster. At this time, the rubbing condition includes the rubbing time, the rubbing speed (the relative speed of the rubbing portion of the rubbing member with respect to the surface of the resin image layer), the pressing force, and the like. Further, as described below, when a rotating member is used as the rubbing member, it is preferable to control the rubbing time and the rotation speed as the rubbing condition.

In the rubbing / fixing step, the rubbing time by the rubbing member varies depending on the melting characteristics of the resin and is not particularly limited, but when rubbing and sticking with a rotating brush, the rubbing time is in the range of 1 to 30 seconds. It is preferable that the inside is excellent in color metallic feeling while maintaining metallic luster, and further, powder particles can be attached to the resin image layer with sufficient adhesive force to prevent detachment.
Further, in the rubbing / fixing step, the relative speed of the rubbing portion of the rubbing member with respect to the surface of the resin image layer is not particularly limited, but is preferably in the range of 5 to 500 mm / sec. When it is 5 mm / sec or more, the orientation of the powder can be sufficiently aligned with the surface of the resin image layer. Further, when it is 500 mm / sec or less, powder particles can be sufficiently adhered to the resin image layer, and the desired appearance of metallic luster and color metallic feeling in the finally formed image is clarified. can do.

Further, in the rubbing / fixing step, the contact width of the rubbing portion of the rubbing member with respect to the surface of the resin image layer is not particularly limited, but the desired orientation and recording of the powder adhering to the surface of the resin image layer are recorded. From the viewpoint of transportability of the medium, the range is preferably 1 to 200 mm. When it is 1 mm or more, it is possible to suppress the variation in the orientation of the powder when the rubbing portion moves along the surface of the resin image layer, and it is possible to sufficiently control the orientation of the powder particles adhering to the resin image layer. it can. Further, when it is 200 mm or less, the recording medium can be stably and easily conveyed. The "contact width" refers to the length of the rubbing portion of the rubbing member with respect to the resin image layer in the moving direction.

When pressing is performed together with rubbing, the pressing pressure is not particularly limited, but is preferably in the range of 1 to 300 kPa with respect to the surface of the resin image layer. When it is 1 kPa or more, the adhesion strength of the powder particles to the resin image layer can be sufficiently obtained. Further, when it is 300 kPa or less, the resin image layer formed on the recording medium can be stably held, and the powder particles are fixed to the surface side without being completely buried in the resin image layer. Can be done.

The rubbing means used in the rubbing / fixing step is not particularly limited, and a known device can be used. As shown in FIG. 6, the rubbing member 15 as the rubbing means according to one embodiment of the present invention is provided after the powder supply device (powder supply means) 10 with respect to the transport direction of the recording medium 103. Is preferable. The arrangement order of these devices is appropriately determined according to the order in which each step is performed.

The rubbing member provided in the rubbing means may be, for example, a rotating member as shown in FIG. 6, a reciprocating member, or a non-rotating member such as a fixed member. Good.
More specifically, the rubbing member has a horizontal direction close to parallel to the surface of the resin image layer so that the powder supplied to the surface of the resin image layer is not completely buried inside the resin image layer. A member that can be rubbed and fixed by applying a force from the above is preferable, and a member that is in contact with the surface of a resin image layer having a horizontal surface and can move in the horizontal direction relative to the surface may be used. However, it may be a rotatable roller (rotating roller), a rotating brush (in the form of an electric toothbrush), a polisher, or the like that is in contact with the surface of the resin image layer. Note that FIG. 6 illustrates a rotating brush that can rotate around an axis.

When a rotating member (particularly, a rotating brush or a rotating roller) is used as the rubbing member, the rotation speed thereof is not particularly limited.

The rubbing member is preferably a rotary roller, a rotary brush, or a polisher whose surface is configured to be relatively movable with respect to the surface of the resin image layer while pressing the resin image layer.
When pressing is performed by the rubbing member, for example, the conveyed recording medium (recording medium on which the resin image layer is formed) may be pressed by the fixed rubbing member. Alternatively, the pressing may be performed by rubbing with a roller that rotates in the same direction as the conveying direction of the recording medium and rotates at a speed slower than the conveying speed of the recording medium, or the recording medium. It may be carried out by rubbing with a roller that rotates in the direction opposite to the transport direction of the recording medium, or a rotatable roller arranged in a direction in which the rotation axis is oblique to the transport direction of the recording medium. The pressing may be performed by rubbing with a member, or the pressing may be performed by rubbing with a member that reciprocates on the surface of the resin image layer.

Therefore, it is preferable that the rubbing member is configured to be movable in a direction relatively different from that of the recording medium while pressing the surface of the resin image layer.

Further, the rubbing member preferably has flexibility. The flexibility of the rubbing member is preferably such that the surface of the rubbing member is deformed to the extent that it can follow the shape of the surface of the resin image layer during rubbing. That is, it is preferable that the rubbing member has a deformation followability. Examples of the rubbing member having such flexibility include, but are not limited to, a sponge, a rotating brush, and the like.

(Additional heating process)
After the rubbing / fixing step, it is preferable to perform an additional heating step. By performing an additional heating step on the powder particles fixed to some extent on the surface of the resin image layer after the rubbing / fixing step, the surface average coverage can be controlled to be 30% or less. it can. That is, by performing an additional heating step after the rubbing / fixing step, the toner seeps out from the gaps between the powder particles to the surface and covers a part of the powder particles, so that the surface average coverage is 30%. It is adjusted as follows.
The additional heating method is not particularly limited as long as it can exude the molten resin to the surface by applying a pressing force to the fixed powder. For example, as shown in FIG. 6, the heating roller 16 and the addition are applied. It is preferable to heat using a pressure roller 17 or the like. The heating roller 16 heats and melts the powder particles 101 that are fixed to the surface of the resin image layer 102 to some extent while transporting them. The heating roller 16 has a rotation axis in a direction perpendicular to the transport direction of the recording medium 103, and sandwiches and transports the recording medium 103 together with the opposing pressure roller 17. The heating roller 16 and the pressure roller 17 have a built-in heat source (not shown) such as a halogen lamp, and heat and melt the resin image layer 102 and the powder particles 101 on the recording medium 103 to form the resin image layer 102. Make it sticky. The heating roller 16 is preferably covered with a heat insulating member.

The heating roller and the pressure roller used in the additional heating step preferably have, for example, a structure in which a silicone rubber layer is provided on an aluminum substrate, and a heat source such as a halogen lamp is built in the inside.
The suitable range of the heating amount in the additional heating step differs depending on the combination of temperature, pressure, nip width, nip time, etc., depending on the melting characteristics of the resin and the configuration of the additional heating step. In the case of the configuration in which the additional heating step is performed, the surface temperature of the heating roller is preferably set to be in the range of 90 to 120 ° C., and the surface temperature of the pressure roller is set to be in the range of 60 to 170 ° C. It is preferable that the surface average coating ratio can be controlled to 30% or less, whereby the metallic luster is maintained and the color metallic feeling is excellent. The surface temperatures of the heating roller and the pressure roller are preferably controlled by the thermistor. Further, the nip width between the heating roller and the pressurizing roller used in the additional heating step is preferably in the range of 1 to 15 mm, and the transport speed of the recording field is in the range of 50 to 300 mm / sec. Is preferable.

The image forming method of the present invention includes, for example, a resin image layer forming step, a powder removing step, a reprint printing step, and other steps in addition to the powder feeding step, the rubbing / fixing step, and the additional heating step. You may.

(Resin image layer forming process)
The image forming method of the present invention may further include a resin image layer forming step before the powder feeding step.

In the resin image layer forming step, the resin image layer is formed on the recording medium. The method of forming the resin image layer on the recording medium is not particularly limited. For example, it is formed by applying a solution obtained by dissolving a compound, a resin that is softened by heating, and other components (for example, a colorant) contained optionally in a suitable solvent on the surface of a recording medium and drying the solution. can do. In this case, the resin image layer can be coated by commonly used methods such as gravure coating, roll coating, blade coating, extrusion coating, dip coating, and spin coating.

Further, the resin image layer may be an image printed on a recording medium by a printing method such as an inkjet method or an electrophotographic method (electrophotograph method). The image formation by the inkjet method and the electrophotographic method can be performed by a known image forming apparatus, respectively.

From the viewpoint that the effects of the present invention can be more easily obtained, the resin image layer is preferably an image formed by an electrophotographic method. In the electrophotographic method, toner particles are adhered to an electrostatic latent image pattern on the surface of a photoconductor to form a toner image, and the toner image is transferred to a recording medium such as paper. Here, the toner particles forming the toner image generally include a thermoplastic resin as a binder resin. Therefore, since the image (toner image) formed by the electrophotographic method is easily softened or melted by heating, it is considered that the effect of the present invention can be exhibited more remarkably.

Further, in the image forming method of the present invention, the resin image layer may be an image before being fixed on the recording medium (unfixed image) or a fixed image (fixed image). Good.
The resin image layer is preferably a fixed image fixed on a recording medium from the viewpoint that powder easily adheres to the surface of the resin image layer and an image having sufficient glossiness is easily formed. That is, it is preferable that the image forming method of the present invention further includes a fixing image forming step before the powder supply step.

The fixed image forming step can be performed by a known fixed image forming apparatus, particularly an image forming apparatus using an electrophotographic method. As an example of the fixing image forming method, a method of applying heat and pressure to the recording medium on which the toner image is transferred by a fixing means to fix the toner image on the recording medium on the recording medium can be adopted.

(Powder removal process)
The image forming method of the present invention may further include a powder removing step after the powder feeding step or the rubbing / fixing step. In the powder removing step, the powder particles that did not adhere to the resin image layer are removed from the recording medium. At this time, the powder particles removed from the recording medium may be recovered and reused. That is, the image forming method of the present invention further includes a powder recovery step of recovering the powder particles that did not adhere to the resin image layer from the recording medium after the powder supply step or the rubbing / fixing step. You may. As described above, it is preferable to recover the excess powder particles that have not been used for decoration from the viewpoint of economy and reduction of environmental load.

The method for removing or recovering the powder particles is not particularly limited, and a known method can be used. For example, a method of scraping with a member such as a brush or a brush, a method of removing with an adhesive member such as an adhesive tape, a method of sucking powder particles with a known instrument such as a powder collector capable of sucking or adsorbing the powder particles, and the like can be mentioned. Be done. As described above, as the powder removing means (member) or the powder collecting means (member) for performing the powder particle removing or collecting step, as described above, the member such as a brush or a brush, or the powder particle On the other hand, an adhesive member having adhesiveness, a powder collector having a suction member for sucking powder particles, and the like can be used. When the powder particles are magnetic powder, a powder collector having a magnet member may be used.

(Additional printing process)
The image forming method of the present invention may further include a reprint printing step after the additional heating step and / or the powder removing step. In the reprint printing step, an image is further formed on a recording medium having a resin image layer to which powder particles are attached (that is, a glossy image that has already been decorated). Thereby, the surface average coverage of the powder particles fixed on the surface of the resin image layer can be adjusted.
The reprint printing method is not particularly limited, and a known method can be used. For example, a printing method such as an inkjet method or an electrophotographic method can be used. Further, as a reprint printing means for performing the reprint printing process, a known device can be used. From the viewpoint of further improving the added value of the printed matter, it is preferable to further perform the reprint printing process.

(Fixing process)
In the image forming method of the present invention, it is also preferable to provide a fixing step if necessary after the powder supply step or the rubbing / fixing step, the additional heating step, the powder removing step and / or the reprint printing step.
The fixing step is not particularly limited, and can be performed by a known fixing image forming apparatus, particularly an image forming apparatus using an electrophotographic method. As an example of the fixing image forming method, a method of applying heat and pressure to the recording medium on which the toner image is transferred by a fixing means to fix the toner image on the recording medium on the recording medium can be adopted.

Furthermore, it is also preferable that the fixing step is fixed by light irradiation. The irradiation conditions can be adjusted as appropriate.

[Image forming device]
The image forming apparatus for performing the image forming method of the present invention is a powder supply means for supplying powder particles onto a resin image layer formed on a recording medium and melted or softened by heating, and the resin image layer. On the other hand, a heating means for heating, a rubbing means for rubbing and fixing the resin image layer (resin image layer to which the powder particles are attached) to which the powder particles are supplied, and a resin image layer for rubbing and fixing. And additional heating means for adding powder particles.
Further, if necessary, a powder removing means (preferably a powder recovering means) for removing the powder particles that did not adhere to the resin image layer from the recording medium, and a resin image layer to which the powder particles adhered (preferably). That is, it is preferable to further have an image forming means (additional printing means) for forming an image and a means for fixing the image on a recording medium having an already decorated glossy image).
These rubbing means, powder removing means (preferably powder collecting means), image forming means (additional printing means), and fixing means may be provided in the image forming apparatus individually or in combination of two or more. Above all, it is preferable that the image forming apparatus further includes the above-mentioned image forming means (addition printing means) from the viewpoint of increasing the productivity of an image having high added value.

Specific explanations of the above-mentioned powder supply means, heating means, rubbing means, additional heating means, powder removing means (powder recovery means), image forming means (additional printing means), fixing means, and the like are described. , As described in the description relating to each of the above steps.

Further, the above-mentioned image forming apparatus may be provided in the same housing as the housing in which the above-mentioned fixing image forming apparatus is provided, or may be provided outside the housing in which the fixing image forming apparatus is provided. It may have been.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the following examples, the operation was performed at room temperature (25 ° C.) unless otherwise specified. Unless otherwise specified, "%" and "parts" mean "mass%" and "parts by mass", respectively.

[Making toner]
<Preparation of colorant dispersion for magenta>
11.5 parts by mass of sodium n-dodecyl sulfate was added to 160 parts by mass of ion-exchanged water, and the mixture was dissolved and stirred to prepare an aqueous surfactant solution. 15 parts by mass of a colorant (CI Pigment Red 122) was gradually added to this aqueous surfactant solution to obtain "Clearmix W Motion CLM-0.8" (manufactured by M-Technique Co., Ltd., "Clearmix". Used the company's registered trademark) for decentralized processing. In this way, a liquid (dispersion liquid for black) in which fine particles of the magenta colorant were dispersed was prepared.
The particle size of the fine particles of the magenta colorant in the magenta colorant dispersion was 220 nm in terms of volume-based median diameter. The volume-based median diameter was determined by measuring under the following measurement conditions using "MICROTRAC UPA-150" (manufactured by HONEYWELL).
Sample refractive index: 1.59
Sample specific gravity: 1.05 (spherical particle conversion)
Solvent refractive index: 1.33
Solvent viscosity: 0.797 (30 ° C), 1.002 (20 ° C)
0-point adjustment: Ion-exchanged water was added to the measurement cell for adjustment.

<Preparation of colorant dispersion for cyan>
A liquid in which fine particles of a cyan colorant are dispersed in the same manner as in the preparation of the colorant dispersion for magenta except that "CI Pigment Blue 15: 3" is used instead of "CI Pigment Red 122". (Colorant dispersion for cyanide) was prepared.

<Preparation of resin particles for core>
Resin particles for a core having a multilayer structure were produced through the first-stage polymerization, the second-stage polymerization, and the third-stage polymerization shown below.
(A) First-stage polymerization An interface in which 4 parts by mass of polyoxyethylene-2-dodecyl ether sodium sulfate is dissolved in 3040 parts by mass of ion-exchanged water in a reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introduction device. The activator aqueous solution 1 was charged, and the temperature of the solution was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream.
A polymerization initiator solution 1 in which 10 parts by mass of potassium persulfate was dissolved in 400 parts by mass of ion-exchanged water was added to the above-mentioned aqueous surfactant solution 1 to raise the temperature of the obtained mixed solution to 75 ° C. Then, the monomer mixed solution 1 containing the following components in the following amounts was added dropwise to the mixed solution over 1 hour.
Styrene 532 parts by mass n-butyl acrylate 200 parts by mass Methacrylic acid 68 parts by mass n-octyl mercaptan 16.4 parts by mass After dropping the above monomer mixed solution 1, the obtained reaction solution is heated at 75 ° C. for 2 hours. , Stirring to carry out polymerization (first stage polymerization) to prepare resin particles A1.

(B) Second-stage polymerization In a flask equipped with a stirrer, a monomer mixed solution 2 containing the following components in the following amount was put into the flask, and paraffin wax "HNP-57" (Nippon Seiro) was used as a release agent. (Manufactured by Wax Co., Ltd.) 93.8 parts by mass was added, and the mixture was heated to 90 ° C. to dissolve it.
101.1 parts by mass of styrene n-butyl acrylate 62.2 parts by mass 12.3 parts by mass of methacrylate n-octyl mercaptan 1.75 parts by mass On the other hand, 3 parts by mass of polyoxyethylene-2-dodecyl ether sodium sulfate is ion-exchanged water. A surfactant aqueous solution 2 dissolved in 1560 parts by mass was prepared and heated to 98 ° C. After adding 32.8 parts by mass of resin particles A1 to the aqueous surfactant solution 2 and further adding the above-mentioned monomer mixed solution 2, a mechanical disperser "Clearmix" having a circulation path (M-Technique Co., Ltd.) Mix and disperse for 8 hours with (manufactured by the company). By this mixed dispersion, an emulsified particle dispersion 1 containing emulsified particles having a dispersed particle diameter of 340 nm was prepared.
Next, a polymerization initiator solution 2 in which 6 parts by mass of potassium persulfate was dissolved in 200 parts by mass of ion-exchanged water was added to the emulsified particle dispersion 1, and the obtained mixed solution was heated at 98 ° C. for 12 hours. Polymerization (second-stage polymerization) was carried out by stirring to prepare resin particles A2, and a dispersion solution containing the resin particles A2 was obtained.

(C) Third-stage polymerization A polymerization initiator solution 3 in which 5.45 parts by mass of potassium persulfate is dissolved in 220 parts by mass of ion-exchanged water is added to the dispersion liquid containing the resin particles A2, and the obtained dispersion is obtained. A monomer mixed solution 3 containing the following components in the following amounts was added dropwise to the solution under a temperature condition of 80 ° C. over 1 hour.
Styrene 293.8 parts by mass n-butyl acrylate 154.1 parts by mass n-octyl mercaptan 7.08 parts by mass After the dropping is completed, heating and stirring are performed for 2 hours to carry out polymerization (third stage polymerization), and after the completion of polymerization, The core resin particles were prepared by cooling to 28 ° C.

<Preparation of resin particles for shell>
The polymerization reaction was carried out in the same manner except that the monomer mixed solution 1 used in the first stage polymerization in the preparation of the resin particles for the core was changed to the monomer mixed solution 4 containing the following components in the following amounts. And the treatment after the reaction was carried out to prepare resin particles for a shell.
624 parts by mass of styrene 2-ethylhexyl acrylate 120 parts by mass of methacrylic acid 56 parts by mass of n-octyl mercaptan 16.4 parts by mass

<Making magenta toner particles>
(A) Preparation of core part The following components were put into a reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introduction device in the following amounts and stirred. After adjusting the temperature of the obtained mixed solution to 30 ° C., a 5 mol / liter sodium hydroxide aqueous solution was added to the mixed solution to adjust the pH to 8 to 11.
Resin particles for core 420.7 parts by mass Ion-exchanged water 900 parts by mass 300 parts by mass of magenta colorant dispersion Next, an aqueous solution prepared by dissolving 2 parts by mass of magnesium chloride hexahydrate in 1000 parts by mass of ion-exchanged water is stirred. It was added to the above mixture over 10 minutes at 30 ° C. below. After leaving for 3 minutes, the temperature of the mixed solution was started, the temperature of the mixed solution was raised to 65 ° C. over 60 minutes, and the particles in the mixed solution were associated. In this state, the particle size of the associated particles was measured using "Multisizer 3" (manufactured by Coulter), and when the volume-based median diameter of the associated particles reached 5.8 μm, 40.2 parts by mass of sodium chloride was ion-exchanged. An aqueous solution dissolved in 1000 parts by mass of water was added to the mixed solution to stop the association of particles.
After the association was stopped, the core portion was prepared by continuing the fusion of the associated particles by further heating and stirring at a liquid temperature of 70 ° C. for 1 hour as an aging treatment. The average circularity of the core was 0.912 when measured with "FPIA2100" (manufactured by Sysmex Corporation, "FPIA" is a registered trademark of Sysmex Corporation).

(B) Preparation of Shell Next, the temperature of the mixed solution was adjusted to 65 ° C., 50 parts by mass of resin particles for the shell was added to the mixed solution, and 2 parts by mass of magnesium chloride hexahydrate was added to 1000 parts by mass of ion-exchanged water. An aqueous solution dissolved in parts by mass was added to the above mixed solution over 10 minutes. Then, the temperature of the mixed solution was raised to 70 ° C., and the mixture was stirred for 1 hour. In this way, the resin particles for the shell were fused to the surface of the core portion, and then aged at 75 ° C. for 20 minutes to form a shell.
Then, an aqueous solution prepared by dissolving 40.2 parts by mass of sodium chloride in 1000 parts by mass of ion-exchanged water was added to stop the formation of the shell. Further, it was cooled to 30 ° C. at a rate of 8 ° C./min. The generated particles were filtered, washed repeatedly with ion-exchanged water at 45 ° C., and then dried with warm air at 40 ° C. to prepare magenta toner matrix particles having a shell covering the surface of the core portion.

(C) Addition of external additive The following external additive was added to the magenta toner parent particles and subjected to external addition treatment with "Henschel Mixer" (manufactured by Nippon Coke Industries, Ltd.) to prepare magenta toner particles.
Hexamethylsilazane-treated silica fine particles 0.6 parts by mass n-octylsilane-treated titanium dioxide fine particles 0.8 parts by mass The external addition treatment with a Henschel mixer was performed at a peripheral speed of a stirring blade of 35 m / sec and a treatment temperature of 35 ° C. The treatment was carried out under the condition of a processing time of 15 minutes. The particle size of the silica fine particles of the external additive was 12 nm in terms of volume-based median diameter, and the particle size of the titanium dioxide fine particles was 20 nm in volume-based median diameter.

<Preparation of cyan toner particles>
Cyan toner particles were produced in the same manner as in the production of magenta toner particles, except that a cyan colorant dispersion was used instead of the magenta dispersion.

<Example 1>
Using Oji Paper's POD gloss coat (basis weight 128 g / m ² ) as a recording medium, a magenta developer was stored in a modified machine of "AccurioPress C2060" (manufactured by Konica Minolta Co., Ltd., "AccurioPress" is a registered trademark of the company). A 2 cm × 2 cm square patch image was formed on a recording medium using a remodeling machine, and a toner image (resin image) having the patch image was output on the recording medium.
The resin image is placed on a hot plate heated to 90 ° C., and the patch image is placed upward, and Metashine 2025PS (average particle size major axis 25 μm, average thickness 2 μm) manufactured by Nippon Plate Glass Co., Ltd. is placed on the patch image. ) Was sprayed, and the surface of the patch image of the resin image was rubbed with a rotating brush for 20 seconds so as to lick the powder particles to fix the powder particles, and excess powder particles were removed.
The powder-decorated image prepared as described above was passed through an additional heating and fixing device having the following configuration once so that the image surface was in contact with the heating roller side, and additional heating was performed.
-Heating roller: A silicone rubber layer with a thickness of 3 mm is placed on an aluminum substrate with an outer diameter of 100 mm and a thickness of 10 mm, and the surface temperature is set to 150 ° C.-Pressurized roller: Outer diameter of 80 mm and a thickness of 10 mm. A silicone rubber layer with a thickness of 3 mm is placed on an aluminum substrate, and the surface temperature is set to 100 ° C. ・ Heat source: Halogen lamps are placed inside the heating roller and pressure roller (temperature control by thermista).
・ Nip width of heating roller and pressure roller: 7mm
-Image support transport speed: 70 mm / sec The powder-decorated image prepared as described above was image-observed and cross-sectionally observed, and the surface average coverage and the average exposure amount were calculated by the method described later. The rate was 13% and the average exposure was 8%.

<Example 2>
The hot plate temperature of Example 1 was 120 ° C., 0.021 g of Metashine 2025PS (average major axis 25 μm, average thickness 2 μm) manufactured by Nippon Sheet Glass Co., Ltd. was sprayed on the image patch, and the rubbing time with a rotating brush was 20 seconds. A powder-decorated image was prepared as a sheet, and an additional heat fixing device was passed through the paper twice. When the surface average coverage and the average exposure were calculated by the above-mentioned methods by observing the image and cross-section, the surface average coverage was 1% and the average exposure was 2%.

<Example 3>
The hot plate temperature of Example 1 was 90 ° C., 0.042 g of Metashine 2025PS (average major axis 25 μm, average thickness 2 μm) manufactured by Nippon Sheet Glass Co., Ltd. was sprayed on the image patch, and the rubbing time with a rotating brush was 15 seconds. A powder-decorated image was prepared as a sheet, and the additional heat-fixing period was passed once. When the image observation and the cross-sectional observation were carried out and the surface average coating ratio and the average exposure amount were calculated by the above-mentioned method, the surface average coating ratio was 20% and the average exposure amount was 9%.

<Example 4>
The hot plate temperature of Example 1 was 100 ° C., 0.042 g of Metashine 2025PS (average major axis 25 μm, average thickness 2 μm) manufactured by Nippon Sheet Glass Co., Ltd. was sprayed on the image patch, and the rubbing time with a rotating brush was 20 seconds. A powder-decorated image was prepared as a sheet, and the additional heat-fixing period was passed once. When the image observation and the cross-sectional observation were carried out and the surface average coating ratio and the average exposure amount were calculated by the above-mentioned method, the surface average coating ratio was 8% and the average exposure amount was 5%.

<Example 5>
The hot plate temperature of Example 1 was 125 ° C., 0.021 g of Metashine 2025PS (average major axis 25 μm, average thickness 2 μm) manufactured by Nippon Sheet Glass Co., Ltd. was sprayed on the image patch, and the rubbing time with a rotating brush was 20 seconds. A powder-decorated image was prepared as a sheet, and the additional heat-fixing period was passed twice. When the image observation and the cross-sectional observation were carried out and the surface average coating ratio and the average exposure amount were calculated by the above-mentioned method, the surface average coating ratio was 1% and the average exposure amount was 1%.

<Example 6>
The hot plate temperature of Example 1 was 100 ° C., 0.042 g of Metashine 2025PS (average major axis 25 μm, average thickness 2 μm) manufactured by Nippon Sheet Glass Co., Ltd. was sprayed on the image patch, and the rubbing time with a rotating brush was 20 seconds. A powder-decorated image was prepared as a sheet, and the additional heat-fixing period was passed once. When the image observation and the cross-sectional observation were carried out and the surface average coating ratio and the average exposure amount were calculated by the above-mentioned method, the surface average coating ratio was 16% and the average exposure amount was 10%.

<Example 7>
The hot plate temperature of Example 1 was set to 100 ° C., and 0.034 g of Metashine 5480PS manufactured by Nippon Sheet Glass Co., Ltd. was sieved on an image patch so that the average major axis was 500 μm was sprayed and rubbed with a rotating brush. A powder-decorated image was prepared with a rubbing time of 20 seconds, and an additional heating and fixing period was passed once. When the image observation and the cross-sectional observation were carried out and the surface average coating ratio and the average exposure amount were calculated by the above-mentioned method, the surface average coating ratio was 10% and the average exposure amount was 10%.

<Example 8>
The hot plate temperature of Example 1 was 90 ° C., and the average major axis was 5.0 μm and the average thickness was 5.0 μm, which was produced as powder particles on an image patch by the same method as described in paragraph [0037] of Japanese Patent No. 562564. 0.012 g of 0.5 μm powder particles were sprayed, a powder decorative image was prepared with a rubbing time of 20 seconds with a rotating brush, and an additional heat fixing period was passed once. When the image observation and the cross-sectional observation were performed and the surface average coverage and the average exposure amount were calculated by the above method, the surface average coverage was 2% and the average exposure amount was 8%.

<Example 9>
The hot plate temperature of Example 1 was 100 ° C., 0.034 g of Metashy 5090PS (average major axis 90 μm, average thickness 5.0 μm) manufactured by Nippon Sheet Glass Co., Ltd. was sprayed on the image patch, and the rubbing time with a rotating brush was 20. A powder-decorated image was prepared in seconds, and the additional heat-fixing period was passed once. When the image observation and the cross-sectional observation were carried out and the surface average coating ratio and the average exposure amount were calculated by the above-mentioned method, the surface average coating ratio was 9% and the average exposure amount was 9%.

<Example 10>
The hot plate temperature of Example 1 was 90 ° C., and the average particle size was 21 μm and the average thickness was 0, which was produced as powder particles on an image patch by the same method as described in paragraph [0037] of Japanese Patent Application Laid-Open No. 562564. 0.012 g of powder particles of .2 μm were sprayed, a powder decorative image was prepared with a rubbing time of 20 seconds with a rotating brush, and an additional heat fixing period was passed once. When the image observation and the cross-sectional observation were carried out and the surface average coating ratio and the average exposure amount were calculated by the above-mentioned method, the surface average coating ratio was 9% and the average exposure amount was 7%.

<Example 11>
The image patch of Example 1 was output with cyan toner, the hot plate temperature was 90 ° C., and 0.042 g of Metashine 2025PS (average major axis 25 μm, average thickness 2 μm) manufactured by Nippon Sheet Glass Co., Ltd. was sprayed on the image patch. A powder-decorated image was prepared with a rubbing time of 20 seconds with a rotating brush, and an additional heating and fixing period was passed once. When the image observation and the cross-sectional observation were carried out and the surface average coating ratio and the average exposure amount were calculated by the above-mentioned method, the surface average coating ratio was 19% and the average exposure amount was 10%.

<Example 12>
The hot plate temperature of Example 1 was set to 100 ° C., and 0.034 g of Metashine 5480PS manufactured by Nippon Sheet Glass Co., Ltd. was sieved on an image patch so that the average major axis was 510 μm was sprayed and rubbed with a rotating brush. A powder-decorated image was prepared with a rubbing time of 20 seconds, and an additional heating and fixing period was passed once. When the image observation and the cross-sectional observation were carried out and the surface average coating ratio and the average exposure amount were calculated by the above-mentioned method, the surface average coating ratio was 7% and the average exposure amount was 7%.

<Example 13>
The hot plate temperature of Example 1 was 90 ° C., and the average major axis was 3.0 μm and the average thickness was 3.0 μm, which was produced as powder particles on an image patch by the same method as described in paragraph [0037] of Japanese Patent No. 562564. 0.012 g of 0.2 μm powder particles were sprayed, a powder decorative image was prepared with a rubbing time of 20 seconds with a rotating brush, and an additional heat fixing period was passed once. When the image observation and the cross-sectional observation were carried out and the surface average coating ratio and the average exposure amount were calculated by the above-mentioned method, the surface average coating ratio was 8% and the average exposure amount was 6%.

<Example 14>
The hot plate temperature of Example 1 was 120 ° C., and the average particle size was 90 μm and the average thickness was 6 produced as powder particles on an image patch by the same method as described in paragraph [0037] of Japanese Patent Application Laid-Open No. 562564. 0.034 g of 0.0 μm powder particles were sprayed, a powder decorative image was prepared with a rubbing time of 20 seconds with a rotating brush, and an additional heat fixing period was passed once. When the image observation and the cross-sectional observation were carried out and the surface average coating ratio and the average exposure amount were calculated by the above-mentioned method, the surface average coating ratio was 9% and the average exposure amount was 9%.

<Example 15>
The hot plate temperature of Example 1 was 90 ° C., and the average particle size was 21 μm and the average thickness was 0, which was produced as powder particles on an image patch by the same method as described in paragraph [0037] of Japanese Patent Application Laid-Open No. 562564. 0.012 g of powder particles of .1 μm were sprayed, a powder decorative image was prepared with a rubbing time of 20 seconds with a rotating brush, and an additional heat fixing period was passed once. When the image observation and the cross-sectional observation were carried out and the surface average coating ratio and the average exposure amount were calculated by the above-mentioned method, the surface average coating ratio was 9% and the average exposure amount was 7%.

<Example 16>
The hot plate temperature of Example 1 was 90 ° C., and the average major axis was 15 μm and the average thickness was 5 μm, which were produced as powder particles on an image patch by the same method as described in paragraph [0037] of Japanese Patent No. 562564. 0.012 g of non-flat powder particles were sprayed, a powder decorative image was prepared with a rubbing time of 20 seconds with a rotating brush, and an additional heat fixing period was passed once. When the image observation and the cross-sectional observation were carried out and the surface average coating ratio and the average exposure amount were calculated by the above-mentioned method, the surface average coating ratio was 6% and the average exposure amount was 8%.

<Example 17>
The hot plate temperature of Example 1 was 90 ° C., 0.042 g of Metashine 2025PS (average major axis 25 μm, average thickness 2 μm) manufactured by Nippon Sheet Glass Co., Ltd. was sprayed on the image patch, and the rubbing time with a rotating brush was 15 seconds. A powder-decorated image was prepared as a sheet, and the additional heat-fixing period was passed once. When the image observation and the cross-sectional observation were carried out and the surface average coating ratio and the average exposure amount were calculated by the above-mentioned method, the surface average coating ratio was 18% and the average exposure amount was 11%.

<Example 18>
The hot plate temperature of Example 1 was 90 ° C., 0.042 g of Metashine 2025PS (average major axis 25 μm, average thickness 2 μm) manufactured by Nippon Sheet Glass Co., Ltd. was sprayed on the image patch, and the rubbing time with a rotating brush was 15 seconds. A powder-decorated image was prepared as an image, and the image support transfer speed of the additional heating and fixing device was set to 140 mm / s, and the paper was passed once. When the image observation and the cross-sectional observation were carried out and the surface average coating ratio and the average exposure amount were calculated by the above-mentioned method, the surface average coating ratio was 29% and the average exposure amount was 18%.

<Example 19>
The hot plate temperature of Example 1 was 90 ° C., 0.042 g of Metashine 2025PS (average major axis 25 μm, average thickness 2 μm) manufactured by Nippon Sheet Glass Co., Ltd. was sprayed on the image patch, and the rubbing time with a rotating brush was 15 seconds. A powder-decorated image was prepared as an image, and the image support transfer speed of the additional heating and fixing device was set to 210 mm / s, and the paper was passed once. When the image observation and the cross-sectional observation were carried out and the surface average coating ratio and the average exposure amount were calculated by the above-mentioned method, the surface average coating ratio was 30% and the average exposure amount was 19%.

<Example 20>
The hot plate temperature of Example 1 was 90 ° C., 0.042 g of Metashine 2025PS (average major axis 25 μm, average thickness 2 μm) manufactured by Nippon Sheet Glass Co., Ltd. was sprayed on the image patch, and the rubbing time with a rotating brush was 15 seconds. A powder-decorated image was prepared as a result, and then a magenta color image patch was output on the decorated patch. The image was passed through an additional heat fixing device once, the image was observed and the cross section was observed, and the surface average coverage and the average exposure amount were calculated by the above method. As a result, the surface average coverage was 0% and the average exposure amount. Was 0%.

<Comparative example 1>
The hot plate temperature of Example 1 was 90 ° C., and 0.042 g of LG neo # 325 (average major axis 35 μm, average thickness 2 μm) manufactured by Oike Imaging Co., Ltd. was sprayed on the image patch, and the rubbing time with a rotating brush was increased. A powder-decorated image was prepared in 15 seconds, the image was observed and the cross section was observed, and the surface average coating rate and the average exposure amount were calculated by the above method. As a result, the surface average coverage rate was 31% and the average exposure amount was 31%. It was 21%.

<Calculation of average exposure of powder particles in the outermost surface layer>
(Cross section observation method)
After cutting out a powder decorative image in which powder particles are fixed on the surface of the resin image layer and solidifying and embedding it with an embedding resin, the cutting sample is cut and the cut surface is ion milled by an ion milling apparatus. , A sample for cross-sectional observation was prepared.
The observation sample was observed with, for example, an ultra-high resolution field emission scanning electron microscope (S-4800, manufactured by Hitachi High-Technologies Corporation) at a magnification at which 10 powder particles adhering to the resin image layer could be seen in one field of view. The observed image was binarized with LUSEX-AP manufactured by Nireco Corporation, and the exposure amount of each powder particle was calculated by the following method. Then, the average value of each calculated exposure amount was defined as the average exposure amount of the powder particles, and is shown in the table below.

(Average exposure)
Average exposure = (perimeter of powder particles exposed from the resin image layer in the cross-sectional image) / (total circumference of the powder particles in the cross-sectional image) × 100
Perimeter of exposed powder particles (exposed length): Perimeter of the part exposed from the resin image layer Overall circumference of powder particles: Length obtained by actually measuring the entire circumference of powder particles

<Average major axis, average thickness and shape of powder particles>
Sprinkle the powder particles on the double-sided tape to fix them, observe the surface using a microscope VHX-6000 at a magnification that allows the shape of the powder particles to be confirmed, and observe the observed images with LUSEX-AP manufactured by Nireco Co., Ltd. The binarization treatment was performed, and the major axis L, the minor axis l, and the thickness t were arbitrarily measured for 100 powder particles, and the average value was calculated.
The maximum length of the powder particles was defined as the major axis L, the maximum length in the direction orthogonal to the major axis L was defined as the minor axis l, and the minimum length in the direction orthogonal to the major axis L was defined as the thickness t.
Further, when the ratio (l / t) of the minor axis l to the thickness t is 5 or more, it is flat, and when it is less than 5, it is non-flat.
The average major axis was also measured in Example 17 using non-flat powder particles.

<Surface average coverage>
The surface average coverage is determined by taking a photograph with a digital microscope VHX-6000 manufactured by KEYENCE at a magnification of 100 times for any 10 fields of view, binarizing it with LUSEX-AP manufactured by Nireco Corporation, and using the following formula. Each coverage in 10 fields of view was obtained, and an average value was further calculated.
Coverage = (area when viewed from above the powder particles exposed from the surface of the resin image layer) / (area of the surface of the resin image layer) × 100

[Evaluation]
<Metallic luster>
After forming a powder-decorated image, it is measured with a goniometer device (variable-angle spectral reflectance measuring device) (Murakami Color Research Institute, Goniometer GP-5) (Misumi SUS sheet metal panel SFY-MTA as a calibration version). / L110 / X80 was used, the incident angle was 45 °, the tilt angle was 0 °, and the light receiving angle was measured from 0 to 90 °), and the integrated value of the reflected light amount was calculated and compared.
(Standard)
◯: When the integrated value of the reflected light amount is 400 or more, a sufficient metallic feeling is exhibited, and a good metallic feeling is also obtained with the naked eye.
Δ: The integrated value of the amount of reflected light is 200 or more and less than 400, and has a metallic feeling that is not uncomfortable to the naked eye.
X: The integrated value of the reflected light amount is less than 200, the metallic feeling is insufficient, and there is a sense of discomfort even with the naked eye.

<Color metallic feeling>
A tape is attached to a solid patch image formed in a size of 5 cm × 10 cm and decorated with powder, and then the tape is peeled off by hand. The state of the image when the tape was peeled off was observed with the naked eye and a loupe at a magnification of 10 times, and evaluated according to the following criteria.
(Standard)
◯: Has a good color metallic feeling even with the naked eye.
Δ: It has a color metallic feeling even with the naked eye.
X: The underlying color cannot be recognized at all even with the naked eye.

As shown in the above results, the toner image formed by the image forming method of the present invention has a better metallic luster and color metallic feeling than the toner image formed by the image forming method of the comparative example. You can see that.

10 Powder supply device (powder supply means)
11 Powder accommodating part 12 Powder supply roller 13 Heating roller 14 Heater 15 Rubbing member (rubbing means)
16 Heating roller (additional heating means)
17 Pressurized roller (additional heating means)
101 Powder particles 102 Resin image layer 103 Recording medium

Claims (6)

An image forming method in which powder particles are supplied and fixed to a resin image layer formed on a recording medium.
An image forming method characterized in that the surface average coverage of the powder particles fixed to the surface of the resin image layer is 30% or less. The surface average coverage of the powder particles fixed to the surface of the resin image layer is 20% or less, and
The image according to claim 1, wherein the average exposure amount of each powder particle fixed to the surface of the resin image layer from the resin image layer is in the range of more than 0% and 10% or less. Forming method. The image forming method according to claim 1 or 2, wherein the resin image layer is a color toner image layer formed by an electrophotographic method. The image forming method according to any one of claims 1 to 3, wherein the powder particles are flat. Any of claims 1 to 4, wherein the average major axis of the powder particles is in the range of 5 to 500 μm, and the average thickness is in the range of 0.2 to 5.0 μm. The image forming method according to claim 1. The image forming method according to any one of claims 1 to 5, wherein the powder particles contain at least a metal and a metal oxide.

Images