JP2007133069A - Electrophotographic image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic image forming method by which a print having photo-like gloss and high image density is obtained. <P>SOLUTION: The electrophotographic image forming method includes fixing a polymerized toner on an electrophotographic image receiving material having at least one toner receiving layer containing ≥50 mass% of a thermoplastic resin above a support and a heat insulating layer between the support and the toner receiving layer to form an image, wherein the projected area of the polymerized toner after fixing is ≥3 times that of the polymerized toner before fixing. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming method for outputting an image using an electrophotographic image forming apparatus such as a copying machine, a printer, or a facsimile.

  At present, image forming apparatuses using an electrophotographic method are widely used in offices and the like. Plain paper has been used for this electrophotographic image forming equipment, but for electrophotography that forms high-quality full-color images with the spread and development of multicolor images and full-color image forming methods using electrophotography. Image receiving paper has been developed.

  In recent years, there has been a growing demand for photo-like prints comparable to silver halide photographic prints and inkjet output prints, but color output images by electrophotography are still satisfactory in quality compared to the former prints. The situation is not so far.

  These electrophotographic color prints use toner on the order of several μm as an image forming element. Therefore, the gloss is poor and the amount of toner applied is limited, which is necessary to achieve a photographic image. The current situation is that the density has not been realized, and these improvements are strongly desired for photo-like image output.

  One of the methods for expressing gloss in the formed color image is a support having high smoothness. For example, paper such as cast coated paper or RC paper in which both sides of a paper base are coated with a resin is mainly used. A support as a component has been proposed (see Patent Documents 1 to 3). However, since the paper support retains moisture in the paper, the moisture in the paper is vaporized by heat at the time of fixing, and may cause a so-called blister phenomenon, and this phenomenon is particularly This is remarkable for paper supports such as cast-coated paper and RC paper. When such a support is used, elimination of blisters is an important issue.

  In order to solve the above-described problem, a method of fixing by cooling and peeling belt fixing is disclosed (Patent Documents 4 and 5). However, with such a fixing method, the apparatus becomes large, the apparatus cost increases, and the conveyance speed must be reduced, but a photo-like gloss cannot be obtained.

  Further, after fixing, there is disclosed a method for expressing gloss by further embossing a film or performing belt fixing by a cooling peeling method (see Patent Documents 6 and 7). However, when such fixing process is performed twice or more, the device design becomes complicated as the number of processes increases, and there are problems such as poor versatility. There is a demand for a printing technique that can provide a photo-like image with a feeling.

Another problem is that the maximum density is low in an electrophotographic print aiming at a photo-like image. In full-color images, sufficient density does not come out due to insufficient toner transfer amount, etc., and in image receiving paper such as general copy paper, toner enters the paper fiber and the density decreases, and the image becomes difficult to see due to irregular reflection on the surface of the image As a result, it has not been possible to obtain a sufficient density necessary for a photo-like image.
JP 2000-3062 A JP 2000-10327 A JP-A-2005-43474 JP 2004-126427 A JP 2004-133324 A JP 2000-66466 A JP 2005-4038 A

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an electrophotographic image forming method capable of obtaining a photo-like gloss and a high image density print.

  The above object of the present invention is achieved by the following configurations.

  1. Polymerized toner is coated on an electrophotographic image-receiving material having a support having a toner receiving layer containing at least one thermoplastic resin in an amount of 50% by mass or more and a heat insulating layer between the support and the toner receiving layer. An electrophotographic image forming method for fixing and forming an image, wherein the projected area of the polymerized toner after fixing is at least three times the projected area of the polymerized toner before fixing Method for forming a photographic image.

  2. 2. The method of forming an electrophotographic image according to 1 above, wherein the thermoplastic resin is a thermoplastic resin having compatibility with the binder resin of the polymerized toner.

  3. 3. The method for forming an electrophotographic image according to 1 or 2, wherein the heat insulating layer has a void structure.

  According to the present invention, it is possible to provide an electrophotographic image forming method capable of obtaining a photo-like gloss and a print having a high image density.

  Hereinafter, the best mode for carrying out the present invention will be described in detail.

  As a result of intensive studies in view of the above problems, the present inventor has found that the support includes a toner receiving layer containing at least one thermoplastic resin in an amount of 50% by mass or more, and a space between the support and the toner receiving layer. A method for forming an electrophotographic image in which an image is formed by fixing a polymerized toner on an electrophotographic image-receiving material having a heat insulating layer, wherein the projected area of the polymerized toner after fixing is determined by the polymerization before fixing. It has been found that an electrophotographic image forming method characterized in that a photo-like glossiness and a print with high image density can be obtained by an electrophotographic image forming method characterized by being at least three times the projected area of toner. It is up to the invention.

  Details of the present invention will be described below.

<Projected area of polymerized toner>
In the electrophotographic image forming method of the present invention, the polymerization toner is used, and the fixing is performed under the condition that the projected area of the polymerized toner after fixing is at least three times the projected area of the polymerized toner before fixing. And

  The projected areas of the polymerized toner before and after fixing in the present invention can be determined by measuring according to the following method.

On the electrophotographic image-receiving material according to the present invention, after forming and fixing a low-density image having a density difference of about 0.1 with respect to the white background portion (unimaged portion), the fixed polymer toner particles are one particle alone. This can be obtained by observing the existing portion with an optical microscope or the like and measuring the projected area S ₁ . For example, using a light microscope (Nikon, Microphoto-FXA), a fixed polymer toner particle image that has been magnified to a magnification of 500 times is photographed, and the obtained image information is analyzed via an interface, for example, image analysis manufactured by Nicole It can be obtained by performing image analysis using an apparatus (Luzex III). Similarly, the projected area S ₂ of the unfixed polymerized toner particles is obtained, and the enlargement ratio of the projected area before and after fixing can be obtained by S ₁ / S ₂ .

  In the present invention, as a method for forming an electrophotographic image in which the projected area of the polymerized toner before fixing is 3 times or more, an electrophotographic image receiving material having a toner receiving layer containing at least one thermoplastic resin in an amount of 50% by mass or more is used. It is characterized by using. Furthermore, from the viewpoint of further exerting the above effects, it is also preferable to raise the fixing temperature to the extent that the polymer toner does not cause a hot offset phenomenon and to control the nip pressure of fixing.

《Electrophotographic image receiving material》
Next, details of the structure of the electrophotographic image-receiving material according to the present invention will be described.

  The electrophotographic image-receiving material according to the present invention comprises a support having a toner receiving layer containing at least one thermoplastic resin in an amount of 50% by mass or more, and a heat insulating layer between the support and the toner receiving layer. Further, in the electrophotographic image receiving material, the thermoplastic resin used in the toner receiving layer is a thermoplastic resin compatible with the binder resin of the polymerized toner, or the heat insulating layer has a void structure. It is preferable from the viewpoint that the object effect of the present invention can be further exhibited.

(Toner receiving layer)
The toner receiving layer according to the present invention is characterized by containing 50% by mass or more of a thermoplastic resin, and preferably 50% by mass or more and 99% by mass or less.

  Examples of the thermoplastic resin applicable to the toner receiving layer according to the present invention include the following thermoplastic resins.

(A) Polyolefin resins such as polyethylene resins and polypropylene resins, copolymer resins of olefins such as ethylene and propylene and other vinyl monomers, acrylic resins, etc.
(B) Those having an ester bond For example, terephthalic acid, isophthalic acid, maleic acid, fumaric acid, phthalic acid, adipic acid, sebacic acid, azelaic acid, abietic acid, succinic acid, trimellitic acid, pyromellitic acid, etc. An acid component (these dicarboxylic acid components may be substituted with a sulfonic acid group, a carboxyl group, etc.) and a diether derivative of ethylene glycol, diethylene glycol, propylene glycol, bisphenol A, bisphenol A (for example, ethylene of bisphenol A) Alcohol components such as oxide 2 adducts, bisphenol A propylene oxide 2 adducts, etc.), bisphenol S, 2-ethylcyclohexyldimethanol, neopentyl glycol, cyclohexyldimethanol, glycerin, etc. Polyester resin or polymethacrylic acid resin such as polymethyl methacrylate, polybutyl methacrylate, polymethyl acrylate, polybutyl acrylate, etc. obtained by condensation with a hydroxyl group etc. may be substituted in the alcohol component of Ester resin, polycarbonate resin, polyvinyl acetate resin, styrene acrylate resin, styrene-methacrylic acid ester copolymer resin, vinyl toluene acrylate resin and the like. Specific examples include those described in JP-A Nos. 59-101395, 63-7971, 63-7972, 63-7773, and 60-294862. Commercially available products include Byron 290, Byron 200, Byron 280, Byron 300, Byron 103, Byron GK-140, Byron GK-130, etc. manufactured by Toyobo, Kao's Tufton NE-382, Tufton U-5, ATR- 2009, ATR-2010, etc., Unitika Eritel UE3500, UE3210, XA-8153, etc., Nippon Synthetic Chemical Polyester TP-220, R-188, etc. can be mentioned.

(C) Polyurethane resin, etc.
(D) Polyamide resin, urea resin, etc.
(E) Polysulfone resin, etc.
(F) Polyvinyl chloride resin, polyvinylidene chloride resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl propionate copolymer resin, etc.
(G) Polyvinyl butyral, etc., polyol resin, ethyl cellulose resin, cellulose resin such as cellulose acetate resin, etc.
(H) Polycaprolactone resin, styrene-maleic anhydride resin, polyacrylonitrile resin, polyether resin, epoxy resin, phenol resin and the like.

  Each of the above thermoplastic resins may be used alone, or two or more of these thermoplastic resins may be mixed and used.

  When coated paper is used as the support described later, the thermoplastic resin to be applied is, in particular, polyethylene, such as high-density polyethylene or low-density polyethylene, and also other polyolefins such as polypropylene, polyester, etc. Etc. can be preferably used. These resins may be used in combination.

  The toner receiving layer may be a single layer or may be composed of two or more layers. The film thickness of the thermoplastic resin constituting the toner receiving layer is generally from 0.1 to 50 μm, preferably from 0. 5 to 10 μm. The glass transition point of the thermoplastic resin used in the toner receiving layer according to the present invention is 0 ° C. or higher, preferably 20 ° C. or higher.

  As the thermoplastic resin used in the toner receiving layer according to the present invention, it is preferable to select a resin having high compatibility with the binder resin constituting the polymerized toner to be received from the viewpoint that the effects of the present invention can be further exhibited.

  In the present invention, being compatible with the binder resin of the polymerized toner means that the thermoplastic resin of the toner receiving layer and the binder resin of the polymerized toner do not form a boundary in the image after fixing. . As a method of evaluating the compatibility of the polymerized toner with the binder resin, for example, a method of measuring using the solubility parameter described in JP-A-2-263642 is described. As a more appropriate evaluation method, A method for measuring the melting toner inclination angle can be mentioned.

  As a method for measuring the melting toner inclination angle, after molding a toner disk, the toner receiving layer composed of a thermoplastic resin set to a predetermined temperature is brought into close contact with the toner disk, the toner disk is melted, Rapid cooling and solidification. Using this contact angle measuring device manufactured by Kyowa Interface Chemical Co., Ltd., the angle of the bottom of the toner after the toner is solidified is measured twice, and the average value is taken as the molten toner inclination angle.

  When the thermoplastic resin is selected from the viewpoint of the molten toner inclination angle, it is preferable to use a resin having a toner inclination angle of 40 degrees or less between the toner used for color image formation and the thermoplastic resin. The resin of the transparent resin layer having a molten toner inclination angle of 40 degrees or less includes polyester resin, styrene-acrylic ester resin, epoxy resin, polyurethane resin, polymethyl methacrylate resin, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer. And other thermoplastic resins. Particularly preferred is a resin of the same type as the main resin of the toner (a resin containing 50% by mass or more based on the binder resin). That is, if the main resin of the toner is a polyester resin, a polyester resin is used as the resin of the toner receiving layer, and if the main resin of the toner is a styrene-acrylic ester resin, a styrene-acrylic ester resin is used as the resin of the toner receiving layer. Is preferred.

[Insulation layer]
The electrophotographic image receiving material according to the present invention is characterized by having a heat insulating layer between the support and the toner receiving layer.

  By providing the heat-insulating layer according to the present invention below the toner-receiving layer, the thermal energy applied from a thermal head or the like during fixing is blocked from diffusing, and the toner-receiving layer is maintained at a high temperature state. By exhibiting the effect of dissolving and smoothing the impacted polymerized toner particles or embedding in the toner receiving layer, a glossy print can be obtained and a wide fixing temperature range can be obtained.

  The heat insulation layer is generally a layer containing a constituent material having a low thermal conductivity, and a method comprising a resin having a low thermal conductivity, or a method comprising a material containing an air layer or bubbles having a high thermal insulation effect. In the present invention, a heat insulating layer having a high porosity (void capacity) is preferable.

  The porosity of the heat insulating layer according to the present invention may be 30% or more, but is preferably 40% or more, and particularly preferably 50% or more and 80% or less.

  As a material for forming the heat insulating layer having a high porosity defined in the present invention, a material obtained by dispersing foamed plastic, hollow particles, or porous particles in a resin layer is used.

  Foamable plastic is a hollow plastic filler containing a heat-fusible substance as a shell and containing a low-boiling solvent inside, and foams when heated. Examples of the thermoplastic resin that forms the shell of the plastic filler include polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyacrylic acid ester, polyacrylonitrile, polybutadiene, and copolymers thereof. Examples of the blowing agent contained in the shell include propane, isobutane, neopentane, and petroleum ether. For example, there are Micropearl manufactured by Matsumoto Yushi Co., Ltd. and Expandel manufactured by Kemanode.

  As the hollow particles, there are micro hollow bodies formed of various materials such as glass, ceramics, plastics, etc. As the glass micro hollow bodies, borosilicate glass microspheres, for example, Microsel M. manufactured by Grapabell, Inc. are used. The aluminosilicate micro hollow body includes a premix for low foam injection molding and standard injection molding, for example, Fillite manufactured by Nihon Philite.

  When organic hollow particles are used for the heat insulation layer, examples of the hollow particles used in the present invention include thermally expandable hollow particles and capsule-shaped hollow polymers. The heat-expandable hollow particles are hollow particles having a thermoplastic material such as vinylidene chloride-acrylonitrile copolymer as a wall material, and a material containing a heat-expandable gas such as propane, n-butane and isobutane inside the particle. It is. The capsule-like hollow polymer is a polymer that uses a resin such as styrene-acrylic as a wall material, contains water therein, and evaporates into water when dried to form hollow particles. The hollow particles as described above generally have a particle size of about 0.1 to 100 μm, but the particle size of the hollow particles used in the present invention is preferably 0.2 to 10 μm, more preferably 0.00. 3-5 μm. If it is less than 0.3 μm, a sufficient heat insulating effect as hollow particles cannot be obtained, and if it exceeds 10 μm, the smoothness is significantly lowered.

  The resin for dispersing and holding the hollow particles is not particularly limited. For example, styrene-butadiene rubber, styrene-methyl methacrylate-butadiene rubber, acrylic resin, acrylic-styrene resin, acrylic-maleic acid resin, acrylic-vinyl acetate. Resin, emulsion type synthetic resin such as ethylene-vinyl acetate resin, water-soluble polymer such as polyvinyl alcohol, starch, casein, gelatin, carboxymethylcellulose, polyethylene oxide and the like.

  The thickness of the heat insulating layer according to the present invention is generally 20 μm, preferably 30 μm or more, more preferably 30 μm or more and 60 μm or less.

[Other additives for toner receiving layer and heat insulating layer]
In addition to the above-described additives, various additives can be used for the toner image-receiving layer or the heat-insulating layer according to the present invention for the purpose of improving the thermodynamic characteristics.

  Such additives can be appropriately selected according to the purpose, for example, plasticizers, fillers, crosslinking agents, charge control agents, conductive agents, pigments, surfactants, dyes, humidity control agents, Matting agents and the like can be mentioned.

  The plasticizer has a function of adjusting the flow or softening of the toner receiving layer by heat or pressure when fixing the toner. Plasticizers include "Chemical Handbook" (edited by the Chemical Society of Japan, Maruzen), "Plasticizers-Theory and Applications-" (written by Koichi Murai, Koshobo), "Research on plasticizers" It can be selected with reference to "Research" (edited by Polymer Chemistry Association) and "Handbook Rubber / Plastic Compounded Chemicals" (edited by Rubber Digest).

  Moreover, as a filler, a well-known thing can be used as a reinforcing agent for resin, a filler, and a reinforcing material, An organic and inorganic filler are preferable. The filler can be selected with reference to "Handbook Rubber / Plastic Compounding Chemicals" (edited by Rubber Digest Co., Ltd.), "New Edition Plastic Compounding Agent Basics and Applications" (Taiseisha), "Filler Handbook" (Taiseisha), etc. it can.

  Examples of the crosslinking agent include an epoxy group, an isocyanate group, an aldehyde group, an active halogen group, an active methylene group, an acetylene group, and other compounds having two or more known reactive groups in the molecule as a reactive group. Further, a compound having two or more groups capable of forming a bond by ionic bond, coordinate bond, or the like is also included. Examples of the crosslinking agent also include known compounds such as coupling agents for resins, curing agents, polymerization agents, polymerization accelerators, coagulants, film-forming agents, film-forming aids, and the like.

  The charge adjusting agent can be used for the purpose of adjusting toner transfer, adhesion, etc., and preventing charging adhesion of electrophotographic receiving paper. As the charge control agent, any of conventionally known antistatic agents and charge control agents can be used. Surfactants such as cationic surfactants, anionic surfactants, amphoteric surfactants and nonionic surfactants In addition, a polymer electrolyte, a conductive metal oxide, and the like can be used.

Examples of the conductive agent include metal oxides such as ZnO, TiO ₂ , SnO ₂ , Al ₂ O ₃ , In ₂ O ₃ , SiO ₂ , MgO, BaO, and MoO ₃ . These may be used alone or in combination of two or more.

  Examples of the pigment include fluorescent whitening agents, white pigments, colored pigments, and dyes for the purpose of improving image quality, particularly whiteness. The fluorescent whitening agent is a compound that has absorption in the near ultraviolet region and emits fluorescence at 400 to 500 nm. Examples of the fluorescent brightener include stilbene compounds, coumarin compounds, biphenyl compounds, benzoxazoline compounds, naphthalimide compounds, pyrazoline compounds, carbostyril compounds, and the like.

  Various known dyes can be used as the dye, and examples thereof include oil-soluble dyes. Examples of oil-soluble dyes include anthraquinone compounds and azo compounds.

The whiteness of the toner-receiving layer according to the present invention is not particularly limited and can be appropriately selected according to the purpose, but is preferably higher. The whiteness, L ^* value is preferably 80 or more in ^{CIE 1976 (L * a * b} *) color space, and more preferably 85 or more, particularly preferably 90 or more. The white color is preferably as neutral as possible. As a white color, the value of (a ^* ) ² + (b ^* ) ^{2 in} the L ^* a ^* b ^* space is preferably 50 or less, more preferably 18 or less, and particularly preferably 5 or less.

  The smoothness of the toner receiving layer according to the present invention is not particularly limited and can be appropriately selected according to the purpose, but is preferably higher. Further, the smoothness is not particularly limited and can be appropriately selected according to the purpose, but is preferably higher. As the smoothness, the arithmetic average roughness (Ra) is preferably 3 μm or less, more preferably 1 μm or less, and more preferably 0.5 μm or less in the entire region from white without toner to black having the maximum density. It is particularly preferred. The arithmetic average roughness can be measured based on JIS B 0601, B 0651, and B 0652.

The surface electrical resistance of the toner receiving layer according to the present invention is preferably 1 × 10 ⁶ to 1 × 10 ¹⁵ Ω (25 ° C., 65% RH), and other than the toner receiving layer according to the present invention. The surface electrical resistance in the layer is also preferably 1 × 10 ⁶ to 1 × 10 ¹⁵ Ω (25 ° C., 65% RH condition).

  A matting agent can be added to the toner receiving layer according to the present invention. There is no restriction | limiting in particular as a mat agent, According to the objective, it can select suitably, For example, a solid particle etc. are mentioned. The solid particles can be classified into inorganic particles and organic particles.

  A slipping agent can be added to the toner receiving layer according to the present invention. Examples of the slip agent include various known ones such as higher alkyl sulfate, higher fatty acid higher alcohol ester, carbowax, higher alkyl phosphate ester, silicone compound, modified silicone, curable silicone, and the like. Polyolefin wax, fluorine oil, fluorine wax, carnauba wax, microcrystalline wax, silane compound, and the like.

[Support]
As a support according to the present invention, as long as it can withstand the fixing temperature and can satisfy the requirements in terms of smoothness, whiteness, slipperiness, friction, antistatic properties, dents after fixing, etc. There is no restriction in particular, and it can be appropriately selected according to the purpose. In general, “Photographic Engineering Basics-Silver Salt Photography” edited by the Japan Photography Society, published by Corona Co., Ltd. (Showa 54) (223) ) To (240) pages, and photographic supports such as synthetic polymers (films).

  Specific examples of the support include synthetic paper (polyolefin-based, polystyrene-based synthetic paper), high-quality paper, art paper, (double-sided) coated paper, (double-sided) cast-coated paper, and synthetic resin pulp such as polyethylene and natural pulp. Paper, Yankee paper, baryta paper, wallpaper, backing paper, synthetic resin or emulsion impregnated paper, synthetic rubber latex impregnated paper, synthetic resin internal paper, paperboard, cellulose fiber paper, polyolefin coated paper (especially polyethylene) Paper coated on both sides), various plastic films or sheets such as polyethylene terephthalate, polystyrene methacrylate, polyethylene naphthalate, etc., and treatment to give white reflectivity to the plastic film or sheet (for example, titanium oxide into the film) Etc.) Films or sheets, fabrics, metals, such as glasses and the like, polyolefin-coated paper (paper, particularly coated on both sides with polyethylene), cast-coated paper is preferred.

As thickness of a support body, it is 25-300 micrometers normally, 50-260 micrometers is preferable and 75-220 micrometers is more preferable. The stiffness and smoothness of the support are not particularly limited and may be appropriately selected depending on the intended purpose. However, for a photographic image receiving paper, a support close to a color silver salt photograph is preferable. The density of the support is preferably 0.7 g / cm ³ or more from the viewpoint of fixing performance.

  The thermal conductivity of the support is not particularly limited and may be appropriately selected depending on the intended purpose. From the viewpoint of fixing performance, it is 2.1 kW / under 20 ° C. and 65% relative humidity. It is preferably m · h · ° C. or higher. The thermal conductivity can be measured by a method described in JP-A-53-66279 using a transfer paper conditioned according to JIS P8111.

  Various additives appropriately selected according to the purpose can be added to the support according to the present invention within a range that does not impair the effects of the present invention. Examples of additives include whitening agents, conductive agents, fillers, pigments such as titanium oxide, ultramarine blue, and carbon black, and dyes.

  In addition, one or both surfaces of the support according to the present invention can be subjected to various surface treatments and undercoating treatments for the purpose of improving the adhesion with a layer provided thereon. Examples of the surface treatment include a glossy surface, or a fine surface, mat surface, or silk surface surface forming treatment, corona discharge treatment, flame treatment, glow discharge treatment, and plasma treatment described in JP-A-55-26507. An activation process etc. are mentioned. Examples of the undercoating treatment include the method described in JP-A No. 61-84443. These treatments may be performed alone, or may be subjected to an activation treatment after performing the above-described molding treatment or the like, and may further be subjected to a primer treatment after a surface treatment such as an activation treatment, Each of these means can be arbitrarily combined.

  A hydrophilic binder, a semiconductive metal oxide such as alumina sol or tin oxide, and carbon black or other antistatic agent may be applied to the support, the front surface or the back surface of the support, or a combination thereof. . Specific examples of such a support include those described in JP-A No. 63-220246.

[Other component layers]
In the electrophotographic image-receiving material according to the present invention, other constituent layers can be provided in addition to the toner-receiving layer and the heat insulating layer described above. The other constituent layers are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a surface protective layer, an intermediate layer, an undercoat layer, a cushion layer, a charge control (prevention) layer, a reflective layer, and a color. Examples include a taste preparation layer, a storage stability improving layer, an adhesion preventing layer, an anti-curl layer, and a smoothing layer. These may have a single layer structure or a laminated structure. When the support is a reflective support and is a reflective electrophotographic image receiving material in which the toner receiving layer according to the present invention is provided on the support, each layer provided on the support needs to be transparent. Rather, it is preferably white.

  As the opacity of the electrophotographic image-receiving material of the present invention, the value measured by the method defined in JIS P 8138 is preferably 85% or more, more preferably 90% or more.

  In the electrophotographic image-receiving material of the present invention, for the purpose of imparting backside output suitability, improving backside output image quality, improving curl balance, imparting writing properties, inkjet, other print suitability, improving device passability, etc. A back layer can be provided on the side opposite to the side on which the image receiving layer is provided. The back layer may have the same configuration as the image receiving layer side in order to improve the double-sided output suitability. In the back layer, the above-mentioned various additives can be used, and it is particularly preferable to use the above-mentioned matting agent, slip agent, charge adjusting agent and the like. The back layer may be a single layer or two or more layers. In addition, when releasing oil is used for a fixing roller or the like to prevent offset at the time of fixing, it is preferable that the back surface has oil absorbability.

  In the electrophotographic image-receiving material of the present invention, an adhesion improving layer can be provided for the purpose of improving the adhesion between the support, the heat insulating layer, the toner receiving layer, and other constituent layers.

  In the electrophotographic image-receiving material of the present invention, various additives can be used for the purpose of improving the stability of the output image and improving the stability of the image-receiving layer itself. Examples of such additives include various known antioxidants, anti-aging agents, ultraviolet absorbers, light stabilizers, deterioration inhibitors, ozone deterioration inhibitors, preservatives, and antifungal agents.

<Polymerized toner>
In the present invention, the image receiving material for electrophotography according to the present invention is used, and an image is formed using a polymerized toner (hereinafter also simply referred to as toner) by an electrophotographic method.

  The polymerized toner used in the present invention is not particularly limited as long as it is a polymerized toner for electrophotography prepared by a known polymerization method or the like. For example, a suspension polymerization method or an emulsion of necessary additives is added. It is preferable to use a production method in which monomers are emulsion-polymerized in a liquid to produce fine polymer particles, and then an organic solvent, an aggregating agent, and the like are added and associated. In the case of association, a method of preparing by mixing with a dispersion liquid of a release agent or a colorant necessary for the composition of the polymerized toner, and a method of preparing the polymerized toner such as a mold release agent or a colorant in the monomer A method of emulsion polymerization after dispersing the components is preferred. Here, the association means that a plurality of resin particles and colorant particles are fused.

  Although it does not specifically limit as a manufacturing method of a suspension polymerization method, The following manufacturing methods can be raised.

  That is, various constituent materials such as a colorant and, if necessary, a release agent, a charge control agent, and a polymerization initiator are added to the polymerizable monomer, and then a homogenizer, a sand mill, a sand grinder, an ultrasonic disperser, etc. Various constituent materials are dissolved or dispersed in the polymerizable monomer. The polymerizable monomer in which these various constituent materials are dissolved or dispersed is dispersed in oil droplets of a desired size as a polymerization toner in an aqueous medium containing a dispersion stabilizer using a homomixer or a homogenizer. . Thereafter, the stirring mechanism is transferred to the reaction apparatus which is the aforementioned stirring blade, and the polymerization reaction is advanced by heating. After completion of the reaction, the dispersion stabilizer is removed, filtered, washed, and further dried to prepare the polymerized toner according to the present invention.

  In addition, as a method for producing the polymerized toner according to the present invention, a method in which resin particles are prepared by fusing in an aqueous medium can also be mentioned. The method is not particularly limited, and examples thereof include methods disclosed in JP-A-5-265252, JP-A-6-329947, and JP-A-9-15904. That is, a method of associating a plurality of dispersed particles of constituent materials such as resin particles and a colorant, or a plurality of fine particles composed of a resin and a colorant, particularly after dispersing them in water using an emulsifier, the critical aggregation concentration According to the present invention, the above flocculant is added and salted out, and at the same time, the melt is heated and fused at the glass transition temperature or higher of the formed polymer itself, and the particles are heated and dried in a fluid state while containing water. A polymerized toner can be formed. Here, an organic solvent that is infinitely soluble in water may be added simultaneously with the flocculant.

  As a resin component of the polymerized toner, a known resin can be used, but generally, a polyester resin, a styrene-acrylic resin, or the like can be mainly used. When an image is formed on the coating layer, it is preferable to select a resin having high compatibility with a resin component such as an adhesive contained in the coating layer as the resin component of the polymerized toner. From such a viewpoint, as the resin component of the polymerized toner, one or a mixture of two or more of polyester resin, styrene-acrylic ester resin, styrene-methacrylic ester resin and the like is used depending on the purpose. It is preferable.

  The volume average particle diameter of the polymerized toner is preferably in the range of 2 to 10 μm, and more preferably in the range of 3 to 9 μm. If the volume average particle size of the polymerized toner is less than 2 μm, the chargeability tends to be insufficient, and the developability may be lowered. On the other hand, if it exceeds 10 μm, the resolution of the image may be lowered. Therefore, each is not preferable.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

<Manufacture of polymerization toner>
[Preparation of toner particle dispersion]
(Preparation of toner particle dispersion 1)
<Preparation of resin particle dispersion 1>
A solution obtained by mixing 588 g of styrene, 160 g of n-butyl acrylate, 52 g of methacrylic acid, and 12 g of n-octanethiol was dissolved in 10 g of anionic surfactant “Emar 27C” (manufactured by Kao Corporation) in 2700 g of ion-exchanged water. The emulsion was polymerized in a reaction vessel, and 500 g of ion-exchanged water having 15 g of potassium persulfate dissolved therein was added thereto while stirring at a low speed for 10 minutes. After carrying out nitrogen substitution, while stirring the inside of the reaction vessel, the contents were heated with a heating device until the temperature reached 80 ° C., and polymerization was continued for 1 hour.

  After 1 hour, emulsion polymerization was continued (aged) for another 2 hours to prepare a resin particle dispersion 1.

  The particle size of the resin particles in the obtained resin particle dispersion 1 was 15 nm, the glass transition point (Tg) was 58 ° C., and the weight average molecular weight (Mw) was 11,500. The solid content concentration of the resin particle dispersion was 20% by mass.

<Preparation of Colorant Particle Dispersion 1>
Yellow pigment: C.I. I. Pigment Yellow 12 60g
Anionic surfactant: Emar E27C (manufactured by Kao Corporation) 13g
240g of ion exchange water
After mixing each of the above components, the mixture was mixed for 10 minutes using an ultra turrax T50 (manufactured by IKA) as a homogenizer, and then dispersed in an SC-mill, so that the yellow pigment as a colorant had an average particle size. A colorant particle dispersion liquid 1 having a diameter dispersed at 250 nm was prepared.

<Preparation of wax dispersion 1>
Stearyl stearate 88g
Behenyl stearate 6g
Stearyl behenate 3g
3g behenyl behenate
Cationic surfactant: Sanizol B50 (Kao Corporation) 5g
240g of ion exchange water
Each of the above components was mixed for 10 minutes in a round stainless steel reaction vessel using an ultra turrax T50 (made by IKA) as a homogenizer, and then dispersed three times with a pressure discharge type homogenizer to obtain wax particles. A wax dispersion 1 dispersed with an average particle diameter of 0.20 μm was prepared.

<Preparation of toner particle dispersion>
Resin particle dispersion 1 234 parts Colorant particle dispersion 1 30 parts Wax dispersion 1 20 parts Magnesium chloride (manufactured by Ako Kasei Co., Ltd.) 8 parts The above components are mixed and dispersed in a reaction vessel, and then reacted. The container was heated to 90 ° C. with a heating device while stirring.

  While confirming the volume average particle diameter, heating was continued, and when the volume average particle diameter reached 6.2 μm, 33 parts of sodium chloride was added to stop the particle diameter growth, and toner particle dispersion 1 was prepared. did. The obtained toner particles had a volume average particle size of 5.2 μm.

(Preparation of toner particle dispersion 2)
In the preparation of the toner particle dispersion 1, the C.I. I. Toner particle dispersion 2 was prepared in the same manner except that CI Pigment Blue 15: 3 was used. The obtained toner particles had a volume average particle size of 5.1 μm.

(Preparation of toner particle dispersion 3)
In the preparation of the toner particle dispersion 1, C.I. I. Toner particle dispersion 3 was prepared in the same manner except that CI Pigment Red 122 was used. The obtained toner particles had a volume average particle size of 5.1 μm.

(Preparation of toner particle dispersion 4)
Toner particle dispersion 4 was prepared in the same manner as in the preparation of toner particle dispersion 1, except that carbon black: Legal 660R (manufactured by Cabot) was used as the black pigment instead of the yellow pigment. The obtained toner particles had a volume average particle size of 5.1 μm.

[Toner particle solid-liquid separation process]
The toner particle dispersions 1 to 4 prepared above were solid-liquid separated by a rotary cylindrical dehydrator MARKIII model number 60 × 40 (manufactured by Matsumoto Kikai Co., Ltd.) equipped with a filter to prepare a toner cake. Each of the prepared toner cakes was washed with water in a rotary cylindrical dehydrator, scraped off with a scraper inserted into the machine, discharged from the machine, and stored in a container. Thereafter, the stored toner cake is supplied to a dryer: a flash jet dryer (manufactured by Seishin Enterprise Co., Ltd.) and dried until the water content of the toner particles reaches 0.5% by mass. Was made.

[External additive addition process]
To 100 parts by mass of each of the toner particles 1 to 4 prepared above, 0.8 part by mass of hydrophobic silica having a primary particle diameter of 14 nm, 1.0 part by mass of hydrophobic titanium oxide having a needle shape, and a primary particle diameter of 85 nm 1.0 part by weight of hydrophobic silica, 1.0 part by weight of hydrophobic silica with a primary particle size of 140 nm, 0.11 part by weight of oleic acid, 0.05 part by weight of palmitic acid, 0.07 stearic acid, myristate 0 0.03 was added, and mixing was performed for 25 minutes using a Henschel mixer (peripheral speed 30 m / s, manufactured by Mitsui Miike Chemical Co., Ltd.) as a mixer. Thereafter, coarse particles were removed using a sieve having an opening of 45 μm to obtain toners 1 to 4.

  The obtained toner had a volume average particle size of 5.0 μm for toner particle 1, 5.4 μm for toner particle 2, 5.2 μm for toner particle 3, and 5.0 μm for toner particle 4.

<< Preparation of developer >>
A carrier was prepared according to the method described below.

  A ferrite core material having a volume average particle size of 40 μm and a coating layer forming solution are combined, and a mixture of 1000 parts by mass of the ferrite core material and the following coating layer forming solution is vacuum degassed kneader (with an inner wall of 100 ° C. The mixture was stirred for 15 minutes, and then the solvent was distilled off under reduced pressure to obtain a carrier having a coating layer formed on the core particles.

(Coating layer forming solution)
Toluene 150.0 parts Methyl methacrylate 24.1 parts Carbon black 6.0 parts Cross-linked styrene fine particles (number average particle size 0.3 μm) 4.0 parts 3,3,4,4,5,5,6,6 7,7,8,8,9,9,10,10,10-heptadecafluorodecyl methacrylate 2.0 parts Next, each of the toners 1 to 4 prepared above was mixed with the carrier, so that the toner concentration was 6. Mass% developers 1-4 were prepared.

<Production of electrophotographic image receiving material>
[Image receiving material A]
Art paper (Mitsubishi Paper Co., Ltd., Tokishi Art) was used as the image receiving material A.

[Image receiving material B]
A white base paper having a basis weight of 160 g / m ² consisting of 50% by mass sulfate method bleached hardwood pulp (LBKP) and 50% by mass sulfate method bleached softwood pulp (NBSP) was prepared.

On the back surface of this white base paper, polyethylene as a back surface resin layer was melt extruded and laminated at 300 ° C. to cover a back laminate layer of 20 g / m ² .

Next, 91% by mass of polyethylene and 9% by mass of rutile titanium oxide were kneaded on the surface side as a surface resin layer, and then a 15 g / m ² water-resistant resin layer was coated by melt extrusion lamination at 300 ° C. A reflective support 1 having a resin coating layer was produced.

  Next, a polyester resin pellet having a Tg of 67 ° C. is dissolved in a toluene / methyl ethyl ketone mixed solvent as a toner receiving layer on the surface resin layer of the prepared reflective support 1, and the thickness after drying using a wire bar is 8 μm. The image receiving material B was prepared by coating and drying.

[Image receiving material C]
On the surface resin layer of the reflective support 1 used in the preparation of the image receiving material B, the lower layer coating liquid 1 and the upper layer coating liquid 1 having the following composition are used to form the lower layer (heat insulation layer dry film thickness: 65 μm) and an upper layer (thermoplastic resin-containing layer dry film thickness: 5 μm) were applied using a slide hopper type coating apparatus, and then passed through a cooling zone maintained at 4 ° C. for 20 seconds. Thereafter, the image receiving material C was produced by drying in a wind of 30 ° C. for 60 seconds, in a wind of 45 ° C. for 60 seconds, and in a wind of 50 ° C. for 60 seconds. In addition, the solid content ratio of the thermoplastic resin in the upper layer 1 containing the formed thermoplastic resin (acrylic resin) is 88 mass%.

(Lower layer coating solution 1)
Hollow particle dispersion (HP433, manufactured by Rohm & Haas) 40% by mass
Gelatin 5% by mass
2,4-dichloro-6-hydroxy-1,3,5-s-triazine sodium aqueous solution (solid content concentration 4%) 2% by mass
Dioctyl sodium sulfosuccinate aqueous solution (solid content 1%) 8% by mass
45% by weight of water
In addition, the porosity of the lower layer which is a heat insulation layer was 51%.

(Upper layer coating solution 1)
Acrylic resin aqueous dispersion * 1 (Muvinyl 743, made by Nichigo Movinyl)
40% by mass
Dioctyl sodium sulfosuccinate aqueous solution (solid content 1%) 20% by mass
2,4-dichloro-6-hydroxy-1,3,5-s-triazine sodium aqueous solution (solid content concentration 4%) 1% by mass
Gelatin aqueous solution (solid concentration 8%) 15% by mass
24% by weight of water
* 1: The acrylic resin aqueous dispersion contains 40% by mass of an acrylate copolymer and 2% by mass of octylphenyl ether.

[Image receiving material D]
In the preparation of the image receiving material C, the image receiving material D was similarly prepared except that the amount of the acrylic resin aqueous dispersion added in the upper layer coating liquid 1 was changed and the solid content ratio of the thermoplastic resin in the upper layer was changed to 70% by mass. Was made.

[Image receiving material E]
In the preparation of the image receiving material C, the image receiving material E was similarly changed except that the amount of the acrylic resin aqueous dispersion added in the upper layer coating liquid 1 was changed and the solid content ratio of the thermoplastic resin in the upper layer was changed to 52% by mass. Was made.

[Image receiving material F]
In the preparation of the image receiving material C, the image receiving material F was similarly changed except that the amount of the acrylic resin aqueous dispersion added in the upper layer coating liquid 1 was changed and the solid content ratio of the thermoplastic resin in the upper layer was changed to 45% by mass. Was made.

[Image receiving material G]
Plain paper (First Class paper manufactured by Konica Minolta Business Technology) was used as the image receiving material G.

<Formation of print image>
Using the toners 1 to 4 and the developers 1 to 4 prepared above, 8050 (Konica Minolta Business Technology Co., Ltd.), a commercially available full color copier, can set two conditions of 180 ° C. and 200 ° C. as fixing conditions. The image was modified, various images were printed on the image receiving materials A to G described above, and each image sample was obtained in the combination shown in Table 1.

<Evaluation of print image>
(Measurement of projected area of toner before and after fixing)
Since the measurement of the projected area of the toner after fixing is difficult when the toners are overlapped and fixed, the toner that has landed on the white background (fogged portion) of the image is measured with an optical microscope (Nikon, Microphoto-FXA). A toner particle image magnified at a magnification of 500 times is photographed using the image, and the obtained image information is subjected to image analysis using an image analysis device (Luzex III) manufactured by Nicole via the interface, and the projected area S ₁ is calculated. Asked.

Next, the projected area S ₂ of each unfixed toner particle was determined by the same method, and the projected area enlargement ratio S ₁ / S ₂ before and after fixing was calculated.

[Glossiness evaluation]
About the image formed in each image receiving material, each gray density part was measured by a method according to JIS Z 8741, using a digital variable angle gloss meter (manufactured by Suga Test Instruments Co., Ltd., UGV-5D). I asked for a degree.

[Evaluation of relief (image step) resistance]
Regarding the image level difference (relief) of the created photographic image, the level difference at the boundary between the part having the toner image and the part not having the toner image was measured. This image step is measured using a stylus-type roughness meter (KLA, Alpha step manufactured by Tencor), and in the present invention, the image step is preferably 3.0 μm or less, and more preferably 2.0 μm or less. did.

(Measurement of image density)
Each created black solid image was measured with an X-Rite 967 densitometer (manufactured by X-Rite).

  The results obtained as described above are shown in Table 1.

As is apparent from the results shown in Table 1, the image receiving material satisfying the conditions specified in the present invention is used, and the projected area enlargement ratio S ₁ / S ₂ before and after fixing is 3.0 or more. It can be seen that the image of the invention has high gloss, high density and excellent relief resistance compared to the comparative example.

Claims (3)

Polymerized toner is coated on an electrophotographic image-receiving material having a support having a toner receiving layer containing at least one thermoplastic resin in an amount of 50% by mass or more and a heat insulating layer between the support and the toner receiving layer. An electrophotographic image forming method for fixing and forming an image, wherein the projected area of the polymerized toner after fixing is at least three times the projected area of the polymerized toner before fixing Method for forming a photographic image. 2. The method for forming an electrophotographic image according to claim 1, wherein the thermoplastic resin is a thermoplastic resin having compatibility with the binder resin of the polymerized toner. The method for forming an electrophotographic image according to claim 1, wherein the heat insulating layer has a void structure.