JP4185765B2 - Electrophotographic transfer paper and image forming method using the same - Google Patents

Description

【００８２】
＜測定・評価方法＞
〔坪量測定方法〕
坪量は、ＪＩＳ Ｐ ８１２４の方法に基いて測定した。
【００８３】
〔溶融トナー接触角の測定方法〕
既述した溶融トナー接触角の測定方法に基き溶融トナー接触角を求めた。
【００８４】
〔画像部光沢度の測定方法〕
画像部光沢度は、ＪＩＳ Ｚ ８７４１の方法に基づき、光沢測定器（ＧＭ−２６Ｄ型、村上色彩研究所社製）を使用し、定着後画像部について入射角と受光角が６０度の条件で測定した。
【００８５】
〔耐ドキュメントオフセット性の評価〕
実施例および比較例で得られた画像の画像部分と白紙部分を用いて、以下の▲１▼〜▲３▼項に示すような重ね合わせパターンを作成し、４０℃３０％ＲＨおよび５０℃３０％ＲＨ環境下で、荷重４０ｇ／ｃｍ²の条件で１週間保管したのちの画像および白紙部欠陥について以下の基準で評価した。
−画像の重ね合わせパターン−
▲１▼白紙部×白紙部
▲２▼白紙部×ベタ画像部
▲３▼ベタ画像部×ベタ画像部
−画像欠損評価基準−
◎：ベタ画像あるいは白紙部で欠損もなく、光沢感も低下していない。実用上問題無く、品質も優れている。
○：ベタ画像あるいは白紙部で欠損はないが、わずかに光沢感が低下している。実用上問題無い。
△：ベタ画像あるいは白紙部で欠損はないが、光沢感が低下している。実用上問題ある。
×：ベタ画像あるいは白紙部で欠損が発生している。実用上問題あり、品質も著しく劣っている
【００８６】
【発明の効果】
以上に説明したように、本発明によれば、高光沢の画像を形成することができ、且つ、高温保管性に優れた電子写真用転写紙および画像形成方法を提供することができ、実用上極めて有用である。
【図面の簡単な説明】
【図１】 本発明の画像形成方法に好適に用いられる画像形成装置の一例を示す概略構成図である。
【図２】 図２は本発明の画像形成方法の定着工程に用いられる定着装置の一例を示す概略構成図である。
【符号の説明】
１ 熱定着ローラ
２ 加圧ローラ
３ 加熱源
４ 定着部材表面層
５ 弾性層
６ トナー像
７ 被転写体（電子写真用転写紙）
１１ 感光体
１２ ローラ型帯電器
１３ 露光装置
１４ 四色現像器（１４ａ、１４ｂ、１４ｃ、１４ｄ）
１５ 中間転写体
１６ クリーナー
１７ 光除電器
１８ 支軸ローラ（１８ａ、１８ｂ、１８ｃ）
１９ 転写用ローラ
２０ 被転写体（電子写真用転写紙）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic transfer paper used for image formation by electrophotography applied to a color copying machine, a color printer, and the like, and an image forming method using the same.
[0002]
[Prior art]
As a method of forming a color image by an electrophotographic method, an electrostatic latent image is formed for each color by irradiating color separation light on a photoreceptor, and the electrostatic latent image formed for each color is converted into Y (yellow). ), M (magenta), C (cyan) and other color toners are successively developed to form color toner images for each color, and each time a color toner image of each color is formed, this is superimposed on the transfer member and transferred. There is a method of forming a color image by melting and fixing these color toner images.
[0003]
Another method is to form a developed color toner image for each color on the photosensitive member instead of the transfer member, and transfer the superimposed color toner image onto the transfer member. There is a method of forming a color image by heating and melting and fixing.
Furthermore, as another method, a color toner image is superimposed on an intermediate transfer member formed of a belt or the like provided between the photosensitive member and the transfer member, and the superimposed color toner image is collectively transferred to the transfer member and heated and melted. Then there is a method of fixing.
[0004]
A color toner is usually a binder resin in which various dyes or pigments are mixed or dispersed as a colorant, and the particle diameter is from several μm to several tens of μm. As such a color toner receiver, a paper base material such as plain paper, general printing paper, and coated paper is used, and the color toner layered on the paper base material is heated and melted. A color image is formed by fixing.
Since the surface of the color image formed in this way has unevenness of about 10 to 100 μm, for example, it is known that unevenness of the glossiness of the image is caused by the unevenness of the toner layer. (For example, refer to Patent Document 1).
[0005]
In order to improve the above problems, a method is generally known in which a thermoplastic transparent resin layer is provided on a paper substrate and a toner image is embedded in the thermoplastic transparent resin layer by a heat roller fixing device. Further, a toner image is placed on the surface of the image transfer sheet having a glass transition temperature of 40 to 70 ° C. and having a transparent resin layer made of a cross-linked resin soluble in tetrahydrofuran, and the toner is embedded in the transparent resin layer by a belt-like fixing device. A method has been proposed (see, for example, Patent Document 2). Further, a method has been proposed in which a toner image is placed on the surface of an image transfer sheet on which a thermoplastic resin is coated, and the toner is embedded in a transparent resin layer with a belt-like fixing device (see, for example, Patent Documents 3 and 4). ).
[0006]
Further, as a transfer sheet that can obtain gloss matching without gloss unevenness without using a belt-like fixing device, the average molecular weight (Mwa) of the transparent resin on the surface of the transfer sheet and the average molecular weight (Mwb) of the binder resin of the color toner are used. ) And Mwa-Mwb ≧ 10000, and an electrophotographic transfer paper is proposed in which the melting inclination angle with the binder resin of the color toner at the fixing temperature of the transparent resin toner is adjusted to 40 degrees or less. (For example, refer to Patent Document 5).
In addition, an electrophotographic transfer paper in which the transparent resin layer on the transfer sheet surface has a number average molecular weight (Mn) of 5000 to 20000 and a glass transition temperature of 30 to 85 ° C. has been proposed (see, for example, Patent Document 6). . Further, a method has been proposed in which a plasticizer is blended in a thermoplastic resin layer provided on an electrophotographic transfer paper, and a binder or solid component forming the layer is softened during fixing to embed toner in the thermoplastic resin layer. (For example, refer to Patent Document 7).
[0007]
The technique described in the above patent document is provided on the surface of electrophotographic transfer paper by heating and melting the color toner image by applying pressure with a heat roller when fixing the color toner image on the transfer body. It is fixed so as to be embedded in the transparent resin layer. However, in these methods, the blank paper portion becomes highly smooth and gloss is exhibited, but the unevenness on the surface of the image portion cannot be completely smoothed, and the glossiness of the image portion is inferior.
[0008]
In addition, as a problem with the technology described in the above-mentioned patent document, a so-called between the thermoplastic resin layer and the thermoplastic resin layer during storage, or between the thermoplastic resin layer and the image portion is in close contact. The occurrence of a document offset is raised.
When a high gloss image using a thermoplastic resin is heated near or above the glass transition point (Tg) of the thermoplastic resin during storage of the printed matter or transportation of the printed matter, the resin component of the image forming portion It melts and adheres to the back side of the printed matter and the printed matter itself, resulting in image defects. Further, since the surfaces of the thermoplastic resin layers are highly smooth, the contact area when the thermoplastic resin layer surfaces are overlapped with each other is increased, and the thermoplastic resin layer surfaces are likely to be in close contact with each other, thereby deteriorating document offset resistance. This may be one of the causes. Further, the one in which a plasticizer or the like is blended in the thermoplastic resin layer is further deteriorated in offset and storage due to softening of the thermoplastic resin at the time of fixing, and loses its value as a product, compared with the one not blended.
[0009]
[Patent Document 1]
JP 63-92965 A
[Patent Document 2]
Japanese Patent Laid-Open No. 5-127413
[Patent Document 3]
JP-A-5-216322
[Patent Document 4]
Japanese Patent Laid-Open No. 6-11982
[Patent Document 5]
Japanese Patent Laid-Open No. 10-221877
[Patent Document 6]
JP-A-11-160905
[Patent Document 7]
JP 2000-275891 A
[0010]
[Problems to be solved by the invention]
An object of the present invention is to solve the above problems. That is, an object of the present invention is to provide an electrophotographic transfer paper and an image forming method that can form a high gloss image and are excellent in high-temperature storage.
[0011]
[Means for Solving the Problems]
  The above-mentioned subject is achieved by the following present invention. That is, the present invention
    <1> In an electrophotographic transfer paper having a thermoplastic resin layer functioning as a toner image-receiving layer on at least one side of a substrate having a coating layer containing an adhesive and a pigment on at least one side,
  The thermoplastic resin layer has a melting point in the range of 50 ° C to 100 ° C, andOxidize paraffin waxSaponification valueThe200 or moreWasAn electrophotographic transfer paper comprising at least one toner melt viscosity reducing agent.
[0012]
<2> The electrophotographic transfer paper according to <1>, wherein a melt toner contact angle of the toner melt viscosity reducing agent is 45 ° or less.
[0013]
<3> The electrophotographic image described in <1> or <2>, wherein the toner melt viscosity reducing agent is blended in the thermoplastic resin layer in a range of 10% by mass to 80% by mass. Transfer paper.
[0014]
<4> The electrophotographic transfer paper according to any one of <1> to <3>, wherein a thickness of the thermoplastic resin layer is in a range of 3 μm to 20 μm.
[0015]
<5> The electrophotographic transfer paper according to any one of <1> to <4>, wherein the thermoplastic resin layer contains a release agent.
[0016]
<6> a step of forming a latent image on a latent image carrier, a step of developing the latent image using an electrophotographic developer to form a toner image, a step of transferring the toner image to a transfer target, and In the image forming method including a fixing step of heat-pressing the toner image transferred onto the transfer target body onto the transfer target body,
In the image forming method, the fixing step is oilless fixing, and the transfer target is the electrophotographic transfer paper according to any one of <1> to <5>.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
The present inventors diligently studied the structure of the surface layer of the electrophotographic transfer paper that forms a high gloss image. As a result, the present inventors have found the conditions necessary to form a high-quality image and obtain an electrophotographic transfer paper excellent in high-temperature storage, and have completed the present invention based on that. Hereinafter, the present invention will be described separately for an electrophotographic transfer paper and an image forming method.
[0018]
<Electrophotographic transfer paper>
  The electrophotographic transfer paper of the present invention (hereinafter sometimes abbreviated as “transfer paper”) has a coating layer containing an adhesive and a pigment on at least one side.Base materialIn the electrophotographic transfer paper having a thermoplastic resin layer functioning as a toner image-receiving layer on at least one side of the thermoplastic resin layer, the thermoplastic resin layer has a melting point in the range of 50 ° C to 100 ° C.And the saponification value is 200 or more.It contains at least one kind of toner melt viscosity reducing agent.
  Therefore, the transfer paper of the present invention can form a high gloss image and is excellent in high temperature storage.
[0019]
In the present invention, the term “toner melt viscosity reducing agent”, in a broad sense, does not affect the melt viscosity of the toner at room temperature, and is compatible with the toner in the heating temperature range when fixing the toner. The toner has a melt viscosity of at least 10 compared to that of the toner alone.¹It means one having a property of lowering by Pa · s or more.
[0020]
At least one of the toner melt viscosity reducing agents used in the transfer paper of the present invention needs to have a melting point in the range of 50 ° C. to 100 ° C., and in the range of 50 ° C. to 70 ° C. preferable.
If the melting point is less than 50 ° C., the heat storage property after fixing cannot be maintained, and if it exceeds 100 ° C., the liquefaction of the toner melt viscosity reducing agent does not proceed at the time of fixing, and it is difficult to seep out to the surface of the thermoplastic resin layer. The melt viscosity of the compatible toner cannot be reduced.
[0021]
When two or more kinds of toner melt viscosity reducing agents are used, a toner melt viscosity reducing agent having a melting point outside the range of 50 ° C. to 100 ° C. can be used in combination. In the case of using toner, it is preferable to use two or more melting points within the range of 50 to 100 ° C., and the melting points of all types of toner melt viscosity reducing agents used are within the range of 50 to 100 ° C. Is more preferable.
[0022]
In addition, the toner melt viscosity reducing agent used in the transfer paper of the present invention is compatible with the toner at the time of fixing and lowers the viscosity of the toner in the melted state. The melt toner contact angle can be used as an index that indirectly represents the thickness.
In the toner melt viscosity reducing agent used for the transfer paper of the present invention, the melt toner contact angle is not particularly limited, but it is preferably as small as possible. The melt toner contact angle is preferably 45 ° or less, and preferably 40 ° or less. More preferred.
When the contact angle of the molten toner exceeds 45 °, the melt viscosity of the toner at the time of fixing is insufficiently lowered, and a high gloss image may not be obtained.
[0023]
In the present invention, the “molten toner contact angle” means a value measured as follows.
First, a toluene solution containing 3% by mass of a toner melt viscosity reducing agent solution was prepared. Next, toner particles (φ1 to 2 mm) once melted and pulverized were placed on a slide glass. Further, about 7 μl of a toluene solution containing a toner melt viscosity reducing agent was dropped and heated in an oven at 140 ° C. for 15 minutes.
After the heating, the mixture was cooled and the contact angle of the toner solid material containing the toner melt viscosity reducing agent formed on the slide glass was measured, and this contact angle was determined as the melt toner contact angle.
[0024]
However, in the toner particles used for the measurement of the contact angle of the molten toner, the resin component of the toner is made of styrene-n-butyl acrylate resin (composition ratio 80:20, mass average molecular weight 30000), and the glass transition temperature (Tg) thereof is. 55 ° C., average volume particle size distribution is 1.20, toner shape factor is 110, and volume average particle size is 8 μm. The compounding amount of the release agent dispersed in the toner is 10% by mass (in terms of solid content). I used what is. The contact angle of the melted toner with only the toner particles is 70 °.
[0025]
The reason why the toner melt viscosity is lowered by the toner melt viscosity reducing agent is considered as follows. First, when the toner is heated, the molecular motion in the toner particles increases and the distance between the molecules increases. That is, the toner becomes soft and the melt viscosity decreases. In this state, when molecules of the toner melt viscosity reducing agent are inserted between the toner molecules, the space between the toner molecules and the toner molecules is further expanded, and the toner molecules are softer, that is, the melt viscosity is reduced (so-called plastic effect). .
The above-mentioned melt toner contact angle shows how the toner spreads (melted state) when the toner melt viscosity reducing agent is dropped onto the toner particles and heated. Therefore, when the melt viscosity contact angle of the toner is high, This means that the effect is small and the melt viscosity of the toner does not decrease.
[0026]
  The toner melt viscosity reducing agent used for the transfer paper of the present inventionNeeds to have a saponification value of 200 or more. SoOther physical properties are not particularly limitedBut 1The viscosity at 20 ° C. is preferably 35 mPa · s or less.
[0027]
  When the saponification value is less than 200, the compatibility of the toner with the binder resin is lowered, and the effect of lowering the melt viscosity is exhibited.Disappear.
  On the other hand, when the viscosity at 120 ° C. is higher than 35 mPa · s, the toner melt viscosity reducing agent hardly oozes out to the surface of the thermoplastic resin layer, and the melt viscosity of the toner may not be sufficiently lowered.
[0028]
As the toner melt viscosity reducing agent used in the transfer paper of the present invention, as described above, any material may be used as long as it has a melting point in the range of 50 ° C. to 100 ° C. Therefore, it is necessary that the toner has excellent compatibility with the toner in the heating temperature range during fixing. From such a point of view, a release agent blended in the thermoplastic resin layer as described later cannot be used as a toner melt viscosity reducing agent because of poor compatibility with the toner.
As a specific example of the toner melt viscosity reducing agent, an organic compound having a high saponification number and containing many ester bonds can be used. For example, saponification is performed by oxidizing (esterifying) paraffin wax (saponification number of 10 or less) An organic compound having a value of 200 or more can be used as the toner melt viscosity reducing agent.
[0029]
Further, the toner melt viscosity reducing agent is preferably blended in the thermoplastic resin layer in the range of 10% by mass to 80% by mass, and in the range of 20% by mass to 60% by mass. Is more preferable.
When the blending amount is less than 10% by mass, the amount of the toner melt viscosity reducing agent that oozes out on the surface of the thermoplastic resin layer at the time of fixing is small, and the toner melt viscosity reducing effect may be reduced. On the other hand, if the amount is more than 80% by mass or more, the amount of the toner melt viscosity reducing agent that oozes out on the surface of the thermoplastic resin layer is too large, and the toner is caused to flow at the time of fixing, which may disturb the image area.
[0030]
The thickness of the thermoplastic resin layer is preferably in the range of 3 μm to 20 μm, and more preferably in the range of 5 to 15 μm.
If the thickness of the thermoplastic resin layer is less than 3 μm, the toner may not be completely embedded in the thermoplastic resin layer at the time of fixing, and the smoothness of the image receiving surface after fixing may be deteriorated and a high gloss image may not be obtained. Further, when the thickness of the thermoplastic resin layer exceeds 20 μm, the thermoplastic resin layer is hardly softened and the embedding property of the toner is deteriorated.
The thermoplastic resin layer has a surface electrical resistance of 8.0 × 10 at a temperature of 28 ° C. and a relative humidity of 85%.⁸The composition is preferably adjusted to be Ω or more. Further, a pigment, a conductive agent, a release agent, etc. may be blended depending on the purpose.
[0031]
Waxes, higher fatty acids, higher alcohols, higher fatty acid amides and the like can be used as the mold release agent to be blended in the thermoplastic resin layer.
Examples of waxes include vegetable waxes such as carnauba wax and rice wax, petroleum waxes such as paraffin and microcrystalline, and synthetic hydrocarbon waxes such as polyethylene wax. Examples of higher fatty acids include stearic acid, oleic acid, palmitic acid, myristic acid, and lauric acid. Examples of the higher alcohol include lauryl alcohol, myristyl alcohol, stearyl alcoat, cetyl alcohol, and behenyl alcohol. Examples of higher fatty acid amides include stearic acid amide, palmitic acid amide, methylene bisstearyl amide, and ethylene bisstearyl amide.
[0032]
The release agent is preferably blended in the thermoplastic resin within a range of 0.1% by mass to 5% by mass. If the blending amount is less than 0.1% by mass, the releasing effect between the transfer paper at the time of fixing and a fixing member such as a heat roller is insufficient, and the transfer paper may be wound around the fixing member at the time of fixing. In addition, when the blending amount exceeds 5% by mass, the amount of the release agent oozing out onto the surface of the thermoplastic resin layer increases, and the part after the release agent oozes out on the image portion and the white paper portion after fixing. May end up.
[0033]
  Used in the transfer paper of the present invention,Having a coating layer containing an adhesive and a pigment on at least one sideAs the substrate, synthetic paper, fine paper, coated paper, art paper, cast-coated paper, and the like can be used. But,Having a coating layer containing an adhesive and a pigment on at least one sideIt is preferable to use coated paper, art paper, cast coated paper, etc. in order to prevent the surface property of the substrate from affecting the gloss after fixing and to prevent blistering during fixing.That's right.
[0034]
As the adhesive, a water-soluble and / or water-dispersible polymer compound is used. For example, cationic starch, amphoteric starch, oxidized starch, enzyme-modified starch, thermochemically-modified starch, esterified starch, etherification Starches such as starch, cellulose derivatives such as carboxymethylcellulose and hydroxyethylcellulose, natural or semi-synthetic polymer compounds such as gelatin, casein, soy protein and natural rubber, polydienes such as polyvinyl alcohols, isoprene, neoprene and polybutadiene, polybutene , Polyalkenes such as polyisobutylene, polypropylene and polyethylene, vinyl halides, vinyl acetate, styrene, (meth) acrylic acid, (meth) acrylic acid esters, (meth) acrylamide, methyl vinyl ether and other vinyl polymers and copolymers , Styrene Synthetic rubber latex such as diene-based, methyl methacrylate-butadiene-based, polyurethane resin, polyester resin, polyamide resin, olefin-maleic anhydride resin, melamine resin, etc. can be used, and is required for transfer paper. One type or two or more types can be appropriately selected and used depending on the quality.
[0035]
The blending ratio of the adhesive is preferably in the range of 5 to 50 parts by mass with respect to 100 parts by mass of the pigment. When the blending ratio is less than 5 parts by mass, the coated paper surface is eroded by the coating liquid for forming the thermoplastic resin layer when the thermoplastic resin layer is applied onto the obtained coating layer. May not be available. On the other hand, when the blending ratio exceeds 50 parts by mass, bubbles are generated when the coating layer is applied, and the coated surface is roughened, so that good white paper glossiness may not be obtained.
[0036]
Examples of pigments include heavy calcium carbonate, light calcium carbonate, kaolin, calcined kaolin, structural kaolin, delaminated kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, alumina, magnesium carbonate, magnesium oxide, and silica. , Magnesium aluminosilicate, particulate calcium silicate, particulate magnesium carbonate, particulate light calcium carbonate, mineral pigments such as white carbon, bentonite, zeolite, sericite, smectite, polystyrene resin, styrene-acrylic copolymer resin, urea Resins, melamine resins, acrylic resins, vinylidene chloride resins, benzoguanamine resins, fine hollow particles thereof, through-hole type organic pigments, and the like can be used, and one or more of these can be used.
[0037]
In this coating layer coating solution, in addition to these, various auxiliary agents, such as surfactants, pH adjusters, viscosity modifiers, softeners, gloss imparting agents, dispersants, flow modifiers, antistatic agents, Stabilizers, antistatic agents, cross-linking agents, sizing agents, fluorescent brighteners, colorants, UV absorbers, antifoaming agents, water resistance agents, plasticizers, lubricants, preservatives, fragrances, etc., as appropriate It is also possible to mix.
[0038]
  The coating amount of the coating layer is appropriately selected according to the purpose of use of the transfer paper of the present invention,Base paperAn amount that completely covers the surface irregularities is required, and the dry mass is 8 to 40 g / m.²It is preferable that
  As a coating method for forming a coating layer, generally known coating apparatuses such as blade coaters, air knife coaters, roll coaters, reverse roll coaters, bar coaters, curtain coaters, die coaters, gravure coaters, Champlex coaters, brush coaters, A two-roll type or metering blade type size press coater, bill blade coater, short dwell coater, gate roll coater or the like is used as appropriate.
[0039]
  The coating layer isBase paperThe coating layer may be a single layer or a multilayer structure by providing one layer or two or more intermediate layers as required. In the case of double-sided coating or a multilayer structure, the composition and coating amount of the coating solution used for each surface and layer need not be the same, and a layer having desired characteristics can be formed. Can be adjusted appropriately.
  Also,Base paperWhen the coating layer is provided only on one side, the other side (back side) is provided with a synthetic resin layer, a coating layer made of an adhesive and a pigment, or an antistatic layer, etc. to prevent curling and printability. It is also possible to give a grant, a paper supply / discharge suitability, and the like. furtherBase paperIt is needless to say that various application aptitudes can be added to the back surface of the substrate by performing various processes such as adhesion, magnetism, flame resistance, heat resistance, water resistance, oil resistance, and slip resistance.
[0040]
The transfer paper of the present invention is preferably finished by adjusting the moisture content to be in the range of 3 to 10% by mass in the normal drying step, surface treatment step, or the like during its production. It is more preferable to finish by adjusting so as to be in the range of%.
[0041]
Further, when the base material is subjected to the smoothing process, it is performed using a smoothing processing apparatus such as a normal super calendar, gloss calendar, soft calendar or the like. Moreover, you may carry out suitably by an on-machine or an off-machine, and the form of a pressurization apparatus, the number of pressurization nips, heating, etc. are suitably adjusted according to a normal smoothing processing apparatus.
[0042]
The base paper of the coated paper used as the substrate is not particularly limited. For example, acidic paper having a papermaking pH of around 4.5, weakly acidic to about 6 having a papermaking pH of about 6 containing an alkaline filler such as calcium carbonate as a main component. A paper substrate such as neutral papermaking having 9 weak alkalinity is used. As for the paper making method, a general long-mesh multi-cylinder type, a round net single-cylinder type, a Yankee type, a twin-wire type or the like is appropriately used. Moreover, a synthetic paper, a nonwoven fabric, and a synthetic resin film can also be used according to a use.
[0043]
The thermoplastic resin constituting the thermoplastic resin layer is not particularly limited as long as it is a known thermoplastic resin, but it is preferable to use a resin having high compatibility with the toner.
Generally, polyester resin or styrene-acrylic resin is mainly used as the resin component of the toner. Therefore, polyester resin, styrene-acrylic acid ester, styrene-methacrylic acid ester or the like may be used as the thermoplastic resin. One or a mixture of two or more may be used depending on the purpose.
[0044]
Among the thermoplastic resins listed above, it is particularly preferable to use a polyester resin. The following are illustrated as a polyhydric alcohol component and polyhydric carboxylic acid component which comprise a polyester resin.
[0045]
Polyhydric alcohol components include ethylene glycol, propylene glycol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, a monomer obtained by adding olefin oxide to bisphenol A, and the like can be used.
[0046]
Examples of the polyvalent carboxylic acid component include maleic acid, maleic anhydride, fumaric acid, phthalic acid, terephthalic acid, isophthalic acid, malonic acid, succinic acid, glutaric acid, dodecyl succinic acid, n-octyl succinic acid, and n-dodecyl succinic acid. Acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxy-2 -Methyl-2-methylenecarboxypropane, tetra (methylenecarboxy) methane, 1,2,7,8-octanetetracarboxylic acid, trimellitic acid, pyromellitic acid, lower alkyl esters of these acids, and the like can be used. . The polyester resin used in the present invention is synthesized by polymerization of one or more of the polyhydric alcohol components and one or more of the polyvalent carboxylic acid components.
[0047]
For coating the thermoplastic resin layer on the coated paper, generally known coating apparatuses such as a reverse roll coater, a bar coater, a curtain coater, a die coater, and a gravure coater are appropriately used.
[0048]
Further, the sheet coated with the thermoplastic resin layer may be smoothed as necessary, and this smoothing process is performed by a smoothing apparatus such as a normal super calendar, gloss calendar, soft calendar, or the like. . Further, the form of the pressure device, the number of pressure nips, heating, and the like are appropriately adjusted according to a normal smoothing apparatus.
[0049]
<Image forming method>
The image forming method of the present invention is not particularly limited as long as it uses the electrophotographic transfer paper of the present invention in an image forming method using a known electrophotographic method, but specifically, the image forming described below A method is preferred.
A step of forming a latent image on a latent image carrier; a step of developing the latent image using an electrophotographic developer to form a toner image; a step of transferring the toner image to a transfer target; In an image forming method including a fixing step in which a toner image transferred onto a transfer target is heat-pressed onto the transfer target, the fixing step is preferably oil-less fixing. The electrophotographic transfer paper of the present invention is used.
[0050]
The oilless fixing is a fixing method in which fixing is performed without fixing a release agent such as oil on the surface of the fixing member at the time of fixing, and generally a release agent is applied to the surface of the fixing member from a conventional fixing device. This is a fixing method performed using a fixing device that omits a supply means. Further, in the image forming method as described above, other steps may be included as necessary in addition to the four steps.
[0051]
Oil-less fixing is preferably used because no oil is used, so that roughness of the obtained image surface is suppressed and writing on the image surface is facilitated.
[0052]
Next, the image forming method of the present invention will be specifically described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an example of an image forming apparatus preferably used in the image forming method of the present invention.
In FIG. 1, 1 is a heat fixing roller, 2 is a pressure roller, 3 is a heating source, 11 is a photoreceptor, 12 is a roller charger, 13 is an exposure device, 14a is a developer equipped with a developer (cyan), 14b is a developing device loaded with a developer (magenta), 14c is a developing device loaded with a developer (yellow), 14d is a developing device 14a loaded with a developer (black), 14 is a developing device, and 15 is an intermediate transfer member. , 16 is a cleaner, 17 is a light static eliminator, 18a, 18b and 18c are spindle rollers, 19 is a transfer roller, and 20 is a transfer target (electrophotographic transfer paper of the present invention).
[0053]
The image forming apparatus shown in FIG. 1 includes a roller charger 12, an exposure device 13, and cyan, magenta, yellow, and black developers around a photosensitive member 11 that can rotate in the direction of arrow R in a clockwise direction. The developing device 14 incorporating the developing devices 14a, 14b, 14c, and 14d, the belt-like intermediate transfer member 15, the cleaner 16, and the light neutralizer 17 are arranged in this order.
The intermediate transfer member 15 is stretched by support shaft rollers 18a, 18b, and 18c arranged on the inner peripheral surface thereof, and is rotatable in the direction of arrow P. The support roller 18 a is in pressure contact with the photoreceptor 11 via the intermediate transfer member 15. The support roller 18 c is in pressure contact with the transfer roller 19 via the intermediate transfer member 15.
[0054]
In addition, the contacted portion between the outer peripheral surface of the intermediate transfer member 15 and the transfer roller 19 allows the transfer target 20 to be inserted in the arrow Q direction. A heat roller fixing device including a heat fixing roller 1 and a pressure roller 2 in pressure contact with the outer peripheral surface of the intermediate transfer body 15 and the transfer roller 19 is disposed on the arrow Q direction side. The transferred body 20 that has passed through the contact portion between the heat transfer roller 1 and the pressure roller 2 and the contact portion between the outer peripheral surface of the intermediate transfer member 15 and the transfer roller 19 can be inserted in the arrow Q direction. .
[0055]
Image formation using the image forming apparatus shown in FIG. 1 is performed as follows. First, the surface of the photoconductor 11 rotating in the direction of arrow R is charged by the roller charger 12. A latent image is formed on the charged portion of the surface of the photoconductor 11 by exposing the surface of the photoconductor 11 with irradiation light L emitted from the exposure device 13 based on image information corresponding to each color of cyan, magenta, and yellow. The latent image formed on the surface of the photoconductor 11 is developed by developing units 14a, 14b, 14c, and 14d built in the developing device 14, and a toner image is formed for each color. The developed toner image is transferred onto the outer peripheral surface of the belt-like intermediate transfer member 15.
[0056]
The toner image transferred onto the outer peripheral surface of the intermediate transfer member 15 is transferred in contact with the support roller 18 c via the intermediate transfer member 15 as the intermediate transfer member 15 advances in the direction of arrow P. Move between and. When the toner image on the outer peripheral surface of the intermediate transfer member 15 passes through a contact portion (nip portion) between the support roller 18c and the transfer roller 19 that is in pressure contact with the intermediate transfer member 15, this nip. The portion is transferred onto the transfer target 20 inserted in the direction of arrow Q. The toner image transferred onto the transfer target 20 is fixed on the transfer target 20 when the transfer target 20 passes through the contact portion between the heat fixing roller 1 and the pressure roller 2 in the direction of arrow Q. An image is formed.
[0057]
The photosensitive member 11 transfers the toner image onto the outer peripheral surface of the intermediate transfer member 15 and then rotates in the direction of the arrow R. The toner remaining on the photosensitive member 11 is removed by the cleaner 16, and the photosensitive member 11 is moved onto the photosensitive member 11. The remaining residual charge is neutralized by the light neutralizer 17 to prepare for the next image formation.
[0058]
As the fixing device used in the image forming method of the present invention, a contact-type heat fixing device can be used, for example, a heat fixing roller having a rubber elastic layer on a cored bar and, if necessary, a fixing member surface layer, In addition to a heat roller fixing device comprising a pressure roller having a rubber elastic layer on a mandrel and optionally having a fixing member surface layer, and a combination of such a roller and a roller, two members Any of the above can use a combination of a roller and a belt each having a heating and / or pressure function, or a combination of a belt and a belt.
[0059]
For the base material (core) of the fixing member, a material having excellent heat resistance, strong strength against deformation, and good thermal conductivity is selected. In the case of a roller type fixing device, for example, aluminum, iron, copper, etc. In the case of a belt-type fixing device, for example, a polyimide film, a stainless steel belt, or the like is selected. On the surface of the roller-type substrate, an elastic rubber layer usually made of silicone rubber, fluorine rubber or the like is provided on the surface.
[0060]
The fixing member may contain various additives depending on the purpose. For example, the fixing member contains carbon black, metal oxide, ceramic particles such as SiC, etc. for the purpose of improving wear resistance and controlling resistance. May be.
[0061]
Next, the fixing process will be described in detail with reference to the drawings. FIG. 2 is a schematic configuration diagram showing an example of a fixing device used in the fixing step of the image forming method of the present invention. In FIG. 2, 1 is a heat fixing roller, 2 is a pressure roller, 3 is a heating source, 4 is a surface layer of a fixing member, 5 is an elastic layer, 6 is a toner image, and 7 is an object to be transferred (for electrophotography of the present invention). Transfer paper). Reference numerals 1 and 2 shown in FIG. 2 have basically the same functions as reference numerals 1 and 2 shown in FIG.
[0062]
The fixing device shown in FIG. 2 is a device in which a fixing member has a roller shape, and the basic configuration thereof includes a heat fixing roller 1 and a pressure roller 2 disposed opposite thereto. The heat fixing roller 1 includes a heating source 3 for heating inside, and at least one layer such as an elastic layer 5 is provided so as to enclose the heating source 3, and the outer peripheral surface of the elastic layer 5. Is provided with the fixing member surface layer 4 located on the outermost periphery.
Further, the pressure roller 2 includes a heating source 3 for heating inside, and includes the heating source 3, and is provided with at least one layer such as an elastic layer 5 positioned at the outermost periphery. The heating source 3 may not be provided inside the pressure roller 2. The heating source 3 is controlled by a temperature control device (not shown) so that a desired heating temperature is obtained.
[0063]
The contact portion between the heat fixing roller 1 and the pressure roller 2 allows the transfer body 7 on which the toner image 6 is formed on the surface contacting the heat fixing roller 1 to be inserted in the arrow S direction. The toner image 6 is fixed by being heated and pressurized when the transfer body 7 passes through the portion, and an image is formed on the surface of the transfer body 7.
[0064]
Around the heat fixing roller 1, if necessary, a cleaning member for removing toner attached to the surface of the heat fixing roller 1, and a nail (finger) for peeling the transferred object 7 from the surface of the heat fixing roller 1. Etc. may be arranged.
[0065]
The heat fixing roller 1 and / or the pressure roller 2 are preferably provided with an elastic layer 5 having a single layer or a laminated structure, and the thickness of the elastic layer 5 is within a range of 0.1 to 3 mm. Is preferable, and it is more preferable that it is in the range of 0.5 to 2 mm. The elastic layer 5 is made of heat-resistant rubber such as silicone rubber or fluorine rubber, and the rubber hardness is preferably 60 or less. The fixing member having the elastic layer 5 is advantageous in that the fixing member is deformed following the unevenness of the toner image 6 on the transferred body 7 and the smoothness of the image surface after fixing can be improved. is there. When the thickness of the elastic layer 5 exceeds 3 mm, the heat capacity of the fixing member increases, and it takes a long time to heat the fixing member to a desired temperature, and energy consumption may increase. . If the thickness of the elastic layer is less than 0.1 mm, if the thickness is too thin, the deformation of the fixing member cannot follow the unevenness of the toner image, resulting in uneven melting, and distortion of the elastic layer effective for peeling. May not be obtained.
[0066]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited only to the examples shown below. In the examples, “parts” and “%” indicate “parts by mass” and “% by mass” unless otherwise specified.
[0067]
<Example 1>
Commercial basis weight 157g / m²A coated liquid of the following composition is applied to the glossy surface of the cast coated paper (mirror coated gold, manufactured by Oji Paper Co., Ltd.) using a bar coater, the coating thickness is 10 μm, and the coating amount is 10 g / m.²(Absolute dry weight) is applied to form a thermoplastic resin layer, basis weight 167 g / m²An electrophotographic transfer paper was obtained.
[0068]
-Composition of coating solution-
-Thermoplastic resin: Polyester resin (TP220, manufactured by Nippon Synthetic Chemical): 100 parts by mass
Toner melt viscosity reducing agent (paraffin wax, molecular weight: 310, oxidation (mgKOH / g): 4) oxidized (esterified), saponification number 370, melting point 58 ° C., molten toner contact angle 35 °: 10 parts by mass
Release agent (Carnauba wax, manufactured by Toa Kasei Co., Ltd.): 3 parts by mass
[0069]
Next, an unfixed image was formed on the obtained electrophotographic transfer paper. The formed unfixed image has a toner amount of 0.6 mmg / cm with a dot area ratio of 100%.²It adjusted so that it might become.
[0070]
An unfixed image is fixed to 4 kg / cm using a fixing device having the configuration shown in FIG.²Then, the surface temperature of the heat fixing roller was set to 170 ° C., the surface temperature of the pressure roller was set to 150 ° C., and the fixing speed was set to 60 mm / sec to obtain a fixed image.
At this time, the amount of viscosity reduction by the toner melt viscosity reducing agent was 10 Pa · s. The amount of viscosity reduction was determined from values before and after mixing the toner melt viscosity reducing agent shown in Example 1 with the toner (the same applies to the following examples).
[0071]
<Example 2>
An electrophotographic transfer paper was prepared and a fixed image was formed on the surface in the same manner as in Example 1 except that the blending amount of the toner melt viscosity reducing agent was 30 parts by mass. At this time, the amount of viscosity reduction by the toner melt viscosity reducing agent was 50 Pa · s.
[0072]
<Example 3>
  Commercial basis weight 127.9 g / m²Cast coated paper (mirror coated gold, made by Oji Paper Co., Ltd.)Having a coating layer containing an adhesive and a pigmentAn electrophotographic transfer paper was produced in the same manner as in Example 1 except that it was used as a substrate, and a fixed image was formed on this surface. At this time, the amount of viscosity reduction by the toner melt viscosity reducing agent was 50 Pa · s.
[0073]
<Example 4>
The coating thickness of the thermoplastic resin layer is 20 μm, and the coating amount is 20 g / m.²(Absolute dry mass) and the basis weight of the obtained transfer paper is 177 g / m²Except that, an electrophotographic transfer paper was produced in the same manner as in Example 3, and a fixed image was formed on this surface. At this time, the amount of viscosity reduction by the toner melt viscosity reducing agent was 10 Pa · s.
[0074]
<Example 5>
  As a toner melt viscosity reducing agent,Paraffin waxA toner melt viscosity reducing agent having a saponification number of 250 obtained by oxidizing (esterification) (molecular weight: 350, oxidation (mg KOH / g): 5), a melting point of 75 ° C., and a molten toner contact angle of 40 ° was used. Except for the above, an electrophotographic transfer paper was prepared in the same manner as in Example 1, and a fixed image was formed on this surface. At this time, the amount of viscosity reduction by the toner melt viscosity reducing agent was 10 Pa · s.
[0075]
<Comparative Example 1>
In the formation of the thermoplastic resin layer, an electrophotographic transfer paper was prepared and a fixed image was formed on the surface in the same manner as in Example 1 except that a coating liquid comprising the following composition was used.
-Composition of coating solution-
-Thermoplastic resin (polyester resin, TP220, manufactured by Nippon Synthetic Chemical): 100 parts by mass
Release agent (Carnauba wax, manufactured by Toa Kasei Co., Ltd.): 3 parts by mass
[0076]
<Comparative example 2>
Stearyl alcohol (NAA-42, manufactured by Nippon Oil & Fats Co., Ltd., saponification number 150, melting point 23 ° C., molten toner contact angle 40 °) was used as an internal additive instead of the toner melt viscosity reducing agent contained in the coating liquid. An electrophotographic transfer paper was prepared and a fixed image was formed on the surface in the same manner as in Example 1 except that the blending amount was 30% by mass. At this time, the amount of viscosity reduction due to the internal additive was 0 Pa · s.
[0077]
<Comparative Example 3>
Instead of the toner melt viscosity reducing agent contained in the coating liquid, an ester-based synthetic wax (Separjet J-156, manufactured by Chukyo Yushi Co., Ltd., saponification number 50, melting point 104 ° C., molten toner contact angle 60) The transfer sheet for electrophotography was produced in the same manner as in Example 1 except that the blending amount was changed to 30% by mass, and a fixed image was formed on this surface. At this time, the amount of viscosity reduction due to the internal additive was 0 Pa · s.
[0078]
<Comparative example 4>
A commercially available plasticizer (Adekasizer RS-700, manufactured by Asahi Denka Kogyo Co., Ltd .: liquid at room temperature) was used in place of the toner melt viscosity reducing agent contained in the coating liquid, and the blending amount was 30 parts by mass. In the same manner as in Example 1, an electrophotographic transfer paper was prepared and a fixed image was formed on the surface. At this time, the amount of viscosity reduction by the plasticizer was 10 Pa · s.
[0079]
<Comparative Example 5>
A commercially available plasticizer (Adekasizer RN-107, manufactured by Asahi Denka Kogyo Co., Ltd .: liquid at room temperature) was used in place of the toner melt viscosity reducing agent contained in the coating liquid, and the blending amount was 30 parts by mass. In the same manner as in Example 1, an electrophotographic transfer paper was prepared and a fixed image was formed on the surface. At this time, the amount of viscosity reduction by the plasticizer was 20 Pa · s.
[0080]
<Evaluation results>
Table 1 summarizes the evaluation results of the electrophotographic transfer papers obtained in the examples and comparative examples and the fixed images formed on the surfaces thereof. In addition, each evaluation item in Table 1 was measured and evaluated as shown below.
[0081]
[Table 1]

[0082]
<Measurement and evaluation method>
[Basis weight measurement method]
The basis weight was measured based on the method of JIS P 8124.
[0083]
[Measuring method of contact angle of molten toner]
The molten toner contact angle was determined based on the previously described method for measuring the molten toner contact angle.
[0084]
[Measurement method of glossiness of image area]
The glossiness of the image area is based on the method of JIS Z 8741, using a gloss meter (GM-26D type, manufactured by Murakami Color Research Co., Ltd.). It was measured.
[0085]
[Evaluation of document offset resistance]
Using the image portion and the blank paper portion of the image obtained in the example and the comparative example, a superposition pattern as shown in the following items (1) to (3) is created, and 40 ° C. 30% RH and 50 ° C. 30 Load of 40 g / cm under% RH environment²Images and blank page defects after storage for 1 week under the above conditions were evaluated according to the following criteria.
-Image overlay pattern-
(1) Blank page x Blank page
(2) Blank page x solid image
(3) Solid image part x Solid image part
-Image loss evaluation criteria-
(Double-circle): There is no defect | deletion in a solid image or a white paper part, and glossiness does not fall. There are no practical problems and the quality is excellent.
○: There is no defect in the solid image or the blank paper portion, but the glossiness is slightly lowered. There is no practical problem.
Δ: There is no defect in the solid image or the blank paper portion, but the glossiness is lowered. There are practical problems.
X: A defect occurs in a solid image or a blank paper portion. There are practical problems and the quality is remarkably inferior.
[0086]
【The invention's effect】
As described above, according to the present invention, it is possible to provide an electrophotographic transfer paper and an image forming method that can form a highly glossy image and that are excellent in high-temperature storage. Very useful.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an example of an image forming apparatus preferably used in an image forming method of the present invention.
FIG. 2 is a schematic configuration diagram showing an example of a fixing device used in a fixing step of the image forming method of the present invention.
[Explanation of symbols]
1 Thermal fixing roller
2 Pressure roller
3 Heating source
4 Fixing member surface layer
5 Elastic layer
6 Toner image
7 Transfer object (transfer sheet for electrophotography)
11 photoconductor
12 Roller charger
13 Exposure equipment
14 Four-color developer (14a, 14b, 14c, 14d)
15 Intermediate transfer member
16 Cleaner
17 Light static eliminator
18 Support roller (18a, 18b, 18c)
19 Transfer roller
20 Transfer object (transfer sheet for electrophotography)

Claims (5)

In an electrophotographic transfer paper having a thermoplastic resin layer functioning as a toner image-receiving layer on at least one side of a substrate having a coating layer containing an adhesive and a pigment on at least one side,
Wherein the thermoplastic resin layer, a melting point is in the range of 50 ° C. to 100 ° C., and, in that it comprises at least one or more toner melt viscosity reducing agent was 200 or more saponification oxidized paraffin wax An electrophotographic transfer paper.   The electrophotographic transfer paper according to claim 1, wherein the toner melt viscosity reducing agent has a molten toner contact angle of 45 ° or less.   3. The electrophotographic transfer paper according to claim 1, wherein the toner melt viscosity reducing agent is blended in the thermoplastic resin layer in a range of 10% by mass to 80% by mass. .   The electrophotographic transfer paper according to any one of claims 1 to 3, wherein the thermoplastic resin layer has a thickness in a range of 3 µm to 20 µm. Forming a latent image on a latent image carrier; developing the latent image with an electrophotographic developer to form a toner image; transferring the toner image to a transfer target; and the transfer target In an image forming method including a fixing step in which a toner image transferred onto a body is heat-pressed onto the transfer target body,
5. The image forming method according to claim 1, wherein the fixing step is oilless fixing, and the transfer target is the electrophotographic transfer paper according to claim 1.

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