JP2006171784A - Electrophotographic transfer sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic transfer sheet which is stabilized in surface electric resistance value in spite of a change in environmental humidity, is excellent in toner transferability, and is free of tear and deformation due to water and stripping off of a toner layer. <P>SOLUTION: The electrophotographic transfer sheet has a support composed of synthetic paper consisting of polypropyrene as a principal component and an image receiving layer formed on at least one surface thereof and is characterized by containing a synthetic hectolite clay mineral and a binder crosslinked by an oxazoline crosslinking agent in the image receiving layer. A polyurethane ionomer resin is preferably contained as the binder in the image receiving layer. The oxazoline crosslinking agent preferably ranges from 1 to 100 parts by mass per 100 parts by mass polyurethane ionomer resin. Further, the surface electric resistance in a range of temperature 10°C to 30°C and relative humidity 30% RH to 85% RH of the surface of the image receiving layer preferably ranges from 1x10<SP>6</SP>to 1x10<SP>9</SP>Ω. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrophotographic transfer sheet used in a printing apparatus using an electrophotographic system using toner. More specifically, the present invention relates to an electrophotographic transfer sheet that has a stable toner image in a wide humidity range from low humidity to high humidity, and is free from tearing and deformation due to moisture and toner peeling.

  In the electrophotographic method, generally, the surface of a photosensitive member is charged, a latent image of an electrostatic image is formed by exposure, toner is attached to the latent image and developed, the toner image is transferred to a transfer sheet, and the toner image is transferred. Obtained by fixing and fixing with heat. Such a method using a transfer sheet is called an indirect method of electrophotography, and is employed in general plain paper electrophotographic copying machines, laser beam printers, and the like. There is also a method in which the transfer sheet itself serves as a photosensitive member, that is, a method in which a latent image is directly formed on a transfer sheet having a photosensitive layer, and toner development and fixing are performed.

  In recent years, as a transfer sheet used as an indirect electrophotographic printing apparatus, various film sheets including those for OHP can be used in addition to plain paper. In general, the surface of the film sheet is provided with an image receiving layer for improving the transferability and adhesion of the toner, and the back surface is provided with an antistatic layer for obtaining a more stable running property. Yes.

  Conventionally, a paper substrate is mainly used as a recording material used in an electrophotographic printing apparatus, and a plastic film substrate such as a polyester film is used for a specific application. However, when a paper substrate is used, there are problems such as a large amount of deformation at high humidity and insufficient water resistance. In the case of a polyester film, water resistance and high image quality can be obtained, but on the other hand, there is a problem that it is difficult to obtain a high-class feeling because of poor writing property and lack of texture. As a method for solving such a problem, a method using synthetic paper can be cited. Synthetic paper is mainly used alone or laminated. Synthetic paper has no deformation or tear due to moisture, is excellent in water resistance, has high image quality in terms of practicality and quality, and has a matte texture and excellent writing properties. It is also an excellent base material in that it has good properties as a so-called paper. However, when synthetic paper is used as the recording medium, if an electrophotographic printing apparatus is used to form an image, the surface electrical resistance value on the surface of the synthetic paper is too high, resulting in poor transfer of toner, and only an image with low density is obtained. There was no problem.

As a conventional technique, in order to improve toner transferability when an image is obtained by an electrophotographic printing apparatus, an image receiving layer for controlling a surface electric resistance value is formed. Japanese Patent Publication No. 51-34734 (Patent Document 1) discloses an electrophotographic transfer having an organic solvent-soluble resin layer formed on a plastic film and having a surface electrical resistance of 1 × 10 ⁹ to 1 × 10 ¹⁵ Ω. A film is disclosed. This resin layer contains a matting agent, and the toner transferability is good to some extent at normal humidity. However, at low humidity, the surface electrical resistance value is increased and the toner transferability is lowered.

  Japanese Patent Publication No. 59-4286 (Patent Document 2) discloses an electrophotographic film comprising two layers in which an undercoat layer of an anionic or cationic conductive resin and an image receiving layer of an acrylic resin are sequentially laminated on a film. Further, Japanese Patent Application Laid-Open No. 62-238526 (Patent Document 3) discloses an electron in which an undercoat layer containing an organic salt is provided on a film as a conductivity-imparting layer, and an image receiving layer of polymethyl methacrylate. Photographic transfer films have been proposed. When an ion conductive material is used for the undercoat layer in this way, the surface electrical resistance value of the film surface is lowered, but this surface electrical resistance value is easily affected by the amount of water absorbed by the undercoat layer, and thus is greatly increased by changes in environmental humidity. There is a problem that the surface electrical resistance value is lowered, particularly under high humidity, and the transferability of the toner is lowered. Further, since the conductive layer is easily dissolved in water, the fixed toner layer is peeled off from the synthetic paper, and there is a problem that the water resistance characteristic of the synthetic paper cannot be utilized.

Japanese Patent Publication No.51-34734 Japanese Patent Publication No.59-4286 JP-A-62-238526

  The object of the present invention is that the surface electrical resistance value is stable even when the environmental humidity changes, the toner transferability is excellent, and the paper is not torn or deformed by water, and the toner layer does not peel off. It is to provide an electrophotographic transfer sheet.

  As a result of intensive studies on the above problems, the present inventors have provided a highly water-resistant conductive layer on the synthetic paper, thereby controlling the surface electrical resistance value of the synthetic paper within a specific range, and changing the environmental humidity. However, the present inventors have found that an electrophotographic transfer sheet can be obtained in which the toner transferability is small and the toner layer does not peel even when immersed in water.

  That is, the electrophotographic transfer sheet according to the present invention includes a support made of synthetic paper mainly composed of polypropylene, and an image receiving layer formed on at least one surface thereof. It contains a light clay mineral and a binder crosslinked with an oxazoline-based crosslinking agent.

The image-receiving layer preferably contains a polyurethane ionomer resin as a binder, and the mixing ratio of the oxazoline-based crosslinking agent and the polyurethane ionomer resin is 1 for the oxazoline-based crosslinking agent to 100 parts by mass of the polyurethane ionomer resin. It is preferable that it is the range of -100 mass parts. Furthermore, it is preferable that the surface electrical resistance value of the surface of the image receiving layer in the range of a temperature of 10 ° C. to 30 ° C. and a relative humidity of 30% RH to 85% RH is 1 × 10 ⁶ to 1 × 10 ⁹ Ω.

  The electrophotographic transfer sheet according to the present invention has a stable surface electric resistance value in a wide range of environments from low temperature and low humidity to high temperature and high humidity, excellent toner transferability, high image density, and high quality image quality. In addition, the paper is not torn or deformed by water and the toner is not peeled off.

  The binder used in the image receiving layer in the present invention is particularly preferably a polyurethane ionomer resin for the purpose of obtaining excellent heat resistance and water resistance. This polyurethane ionomer resin is also excellent in adhesion to synthetic paper whose main component is polypropylene, which is the support of the present invention.

  The blending ratio of the oxazoline-based cross-linking agent and the polyurethane ionomer resin is preferably in the range of 1 to 100 parts by mass, more preferably in the range of 2 to 50 parts by mass with respect to 100 parts by mass of the polyurethane ionomer resin. . When the amount of the oxazoline-based crosslinking agent is less than 1 part by mass, the water resistance may be inferior. On the other hand, when it exceeds 100 parts by mass, the adhesion between the toner and the image receiving layer may be lowered.

  In the present invention, other polymers than the above can be used in combination with the image receiving layer. For example, starches such as cationic starch, amphoteric starch, oxidized starch, enzyme-modified starch, thermochemically-modified starch, esterified starch, etherified starch, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, carboxymethylcellulose and these Cellulose derivatives such as derivatives, natural or semi-synthetic polymer compounds such as gelatin, casein, soybean protein, natural rubber, vinyl acetate copolymers, acrylic copolymers, epoxy copolymers, polyvinyl alcohol, polyacryl Acid, polyacrylamide, polyhydroxyethyl acrylate, polyvinyl pyrrolidone, water-soluble polyester, water-soluble polyurethane, water-soluble nylon, water-soluble epoxy resin, acrylic resin, polyester, polyvinyl acetate, isoprene, neoprene , Polydienes such as polybutadiene, polyalkenes such as polybutene, polyisobutylene, polypropylene, polyethylene, vinyl halide, vinyl acetate, styrene, (meth) acrylic acid, (meth) acrylic acid ester, (meth) acrylamide, methyl vinyl ether, etc. Synthetic polymers such as vinyl polymers and copolymers, synthetic rubber latex such as styrene-butadiene, methyl methacrylate-butadiene, polyurethane ionomer resin, polyester resin, polyamide resin, olefin-maleic anhydride resin, melamine resin A compound etc. can be illustrated. Of these, one or more kinds may be appropriately selected and used depending on the range that does not impair the quality of the electrophotographic transfer sheet.

In addition, the electrophotographic transfer sheet according to the present invention has a surface electrical resistance value based on JIS K 6911 in the range of a temperature of 10 ° C. to 30 ° C. and a relative humidity of 30% RH to 85% RH of 1 × 10 ⁶ to 1. It is preferably in the range of × 10 ⁹ Ω. Incidentally, if the surface electrical resistance value is less than 1 × 10 ⁶ Ω, the charge amount of the paper is low, the electrostatic attractive force on the surface of the image receiving layer acting on the toner on the photoreceptor is weak, and the transfer may be inferior. In some cases, the toner is missing or the image density is lowered. On the other hand, when the surface electrical resistance value exceeds 1 × 10 ⁹ Ω, toner transfer to unnecessary portions or toner scattering due to discharge may occur, resulting in image defects such as toner covering and image quality degradation. is there.

As such a means for controlling the surface electric resistance value, it is preferable to provide an image receiving layer containing a synthetic hectorite clay mineral. As the synthetic hectorite clay mineral used in the present invention, the same structural formula as natural hectorite clay, that is, the following formula:
[(Si ₈ (Mg _5.34 Li _0.66 ) O ₂₀ (OH, F) ₄ )] Na _0.66
Laponite B, S, etc., manufactured by Laporte Industries, Inc., or a structural formula in which all of (OH, F) ₄ are hydroxyl groups, that is, the following formula:
_{[(Si 8 (Mg 5.34 Li} 0.66) O 20 (OH) 4)] Na 0.66
Laponite RD, RDS, XLG, XLS and the like manufactured by Laporte Industries.

  The present invention is characterized in that an image receiving layer containing a synthetic hectorite clay mineral is provided. The particle diameter of the synthetic hectorite clay mineral used in the present invention is 10 μm or less, preferably 0.2 to 5 μm. The blending ratio is 5 to 90% by mass, preferably 20 to 70% by mass, based on the solid content of the image-receiving layer coating material. When the blending ratio is less than 5% by mass, it is difficult to control the surface electric resistance value, and particularly, the change in the surface electric resistance value due to the change in humidity is large, which may cause transfer defects during recording. On the other hand, if it is more than 90% by mass, the ratio of the binder used as the adhesive in the image receiving layer is lowered, and the adhesive strength between the support and the image receiving layer may be insufficient.

  Laponite as described above has a layered structure, and the thickness of each layer of the crystal structure is about 1 nm, forming a platelet that is extended two-dimensionally. The magnesium atom present in the platelet unit is isomorphously substituted with the lithium atom of the lower valence ion, and the platelet unit is negatively charged, but in the dry state, this negative charge is the lattice structure of the plate surface. It is in balance with the replaceable sodium cation on the outside. When this laponite is dispersed in deionized water at a concentration of 1.5 to 2.0% by mass, the displaceable sodium cation outside the lattice structure is ionized and diffuses from the platelet surface, and the platelet surface is negative. A charge is obtained and repels each other to form a colloidal dispersion in which the platelet units are dispersed, that is, a sol. The dispersed platelet has a negative charge inherent to the whole, and the edge of the platelet has a small local charge due to ion adsorption from the surrounding medium. This depends on the type and concentration of ions in the solution and the pH of the medium, but usually only cations are adsorbed and the edges are positively charged. As a result, end-to-face bonds occur to form a typical “card house” structure and form a gel. This gel strength depends on the concentration of laponite, and in the case of a low concentration, a relatively loose particle chain network is formed, and the gel strength is low, but if the concentration is increased, the particle chain network is filled. Gel strength increases rapidly.

  On the other hand, Laponite S, RDS, and XLS that form a sol contain a peptizer such as sodium pyrophosphate to enable the preparation of a stable fluid dispersion when the concentration reaches 10% by mass. This peptizer is adsorbed on the edge of a positively charged platelet and becomes a large amount of negatively charged ions, preventing the direct formation of a gel structure caused by interparticle bonding.

A polymer, pigment, lubricant, crosslinking agent, surfactant and the like may be added to the image-receiving layer coating solution in the present invention for the purpose of improving film uniformity, bondability and coating suitability. Moreover, it is also possible to add a normal electroconductive substance in the range which does not impair the desired effect of this invention.

  In the present invention, other pigments used in the image receiving layer are not particularly limited. For example, kaolin, structural kaolin, derami kaolin clay, talc, heavy calcium carbonate, light calcium carbonate, calcium sulfate, barium sulfate, calcined clay, titanium oxide, diatomaceous earth, acid value zinc, alumina, magnesium carbonate, magnesium oxide, silica , Particulate anhydrous silica, activated clay, colloidal silica, magnesium aluminosilicate, particulate calcium silicate, particulate magnesium carbonate, particulate light calcium carbonate, white carbon, bentonite, zeolite, sericite, smectite and other inorganic pigments and poly Methyl methacrylate, polycarbonate, polyethylene terephthalate, polystyrene resin, styrene-acrylic copolymer resin, urea resin, melamine resin, acrylic resin, vinylidene chloride resin, benzoguanamine Such as butter, Mitsumi type, fine hollow particles type, the through-hole type and organic pigments are mentioned, it is possible to use alone or in combination of two or more appropriately from these.

  Furthermore, in the present invention, various auxiliary agents can be added to the image-receiving layer coating solution as necessary. For example, dioctyl sodium sulfosuccinate, sodium dodecyl benzene sulfonate, sodium lauryl alcohol sulfate, fatty acid metal salt and other dispersants, surfactants, other antifoaming agents, UV absorbers, fluorescent dyes, coloring dyes, pH regulators , Viscosity modifiers, softeners, gloss imparting agents, waxes, flow modifiers, antistatic agents, stabilizers, antistatic agents, crosslinking agents, sizing agents, fluorescent whitening agents, colorants, UV absorbers, water resistance Agents, plasticizers, lubricants, preservatives, fragrances, and the like can be appropriately used as necessary.

Synthetic paper mainly composed of polypropylene is used as the support in the present invention. As a method for producing this synthetic paper, the following methods are generally known. It is not limited.
(1) Internal paper forming method: This is a method in which a filler and additives are added to a synthetic resin, mixed, melt-kneaded with an extruder, and then extruded from a die slit to form a film. There are a forming method and a biaxially stretched film forming method.
(2) Surface coating method: A method of providing a white pigment coating layer on the surface of a plastic film.
(3) Surface treatment method: A method of chemically or physically treating the surface of a synthetic resin film.

  Specific examples of such synthetic paper include, for example, 260LLG-202 manufactured by Mobil Corporation, P4255 manufactured by Toyobo Co., Ltd., PEPPART, POLYART manufactured by Arjobex Corporation, and peach coat manufactured by Nisshinbo Co., Ltd.

  In particular, in the present invention, it is preferable to use a synthetic paper obtained by the biaxially stretched film forming method of the internal paper forming method as a support. Specifically, inorganic fillers and additives are added to and mixed with the polypropylene resin as the main raw material, melted and kneaded with an extruder, then the molten resin film is extruded from the die slit, once cooled, and then heated to around the softening temperature again. In addition, synthetic paper obtained by a method of forming a film by stretching the film in the vertical and horizontal directions simultaneously or sequentially is preferable. Further, during the stretching by this method, the film is formed while generating microvoids which are fine pores inside. Synthetic paper obtained as described above can also be preferably used in the present invention.

  A specific example of such synthetic paper is a product name “YUPO” manufactured by Yupo Corporation, and grade names: FPG, SGS, KPK, KAG, KPU, KPE, QJJ, WFP, and the like. “YUPO” is formed by using a biaxially stretched film forming method as a raw material with a microvoid formed as a raw material obtained by adding an inorganic filler such as calcium carbonate and an additive to polypropylene resin. “Yupo” has a multilayer structure composed of a base layer and paper layers laminated on both surfaces thereof. The base layer is stretched and oriented in the longitudinal and transverse directions, mainly maintaining strength and rigidity, while the surface layer is oriented and oriented only in the transverse direction, and light is irregularly reflected by a large number of microvoids, resulting in high whiteness, water resistance, It is preferable in that it is excellent in durability, moisture resistance, smoothness, etc., maintains opacity, imparts writing properties and printability, has a low specific gravity and is lightweight. The thickness of the synthetic paper is preferably in the range of 20 to 500 μm, and more preferably in the range of 35 to 300 μm.

In the electrophotographic transfer sheet according to the present invention, the method for forming the image receiving layer is not particularly limited. For example, air knife coating, wire bar coating, blade coating, roll coating, gravure coating, reverse roll coating, curtain coating, It is formed by a method of applying and drying a coating solution by die slot coating, champlex coating, brush coating, two-roll or metering blade type size press coating, bill blade coating, gate roll coating, and the like. The present invention is not particular limitation on the coating amount of the coating liquid, 0.1 to 10 g / ^{m 2} approximately at normal dry mass per one surface, preferably, it is adjusted in the range of 0.1-5 g / ^{m 2.} When the coating amount is less than 0.1 g / m ² g, the surface electrical resistance value is high, and the toner transferability may be inferior. On the other hand, when it exceeds 10 g / m < ² >, cost becomes high. In addition, after application | coating and drying, you may smooth | blunt with a super calendar, a machine calendar, a soft calendar, etc.

  The image receiving layer may be formed on one side or both sides of the support, and may have a multilayer structure by providing one layer or two or more intermediate layers as required. In addition, when it is set as double-sided coating or a multilayer structure, each coating liquid does not need to be the same or the same coating amount, and what is necessary is just to adjust suitably according to a desired quality level, and is not specifically limited. In addition, when an image receiving layer is provided on one side of the support, a synthetic resin layer, a coating layer made of pigment and adhesive, an antistatic layer, etc. are provided on the back side to prevent curling, printing suitability, feeding / ejection suitability, and blocking prevention. It is also possible to impart sex and the like. In addition, various processing on the back surface of the support, such as adhesion, magnetism, flame retardant, heat resistance, water resistance, oil resistance, slip resistance, or various recording aptitudes such as thermal recording, thermal transfer recording and ink jet recording, etc. Of course, it is also possible to use it.

  The surface of the image receiving layer has a Beck smoothness based on JIS P 8119 of 50 seconds or more, preferably 200 to 4000 seconds. When the Beck smoothness is less than 50 seconds, toner transfer failure may occur, and image quality may deteriorate. The Clark stiffness of the transfer sheet based on JIS P 8143 is 5 cm or more in both the machine direction and the cross direction, preferably 10 to 500 cm. If the Clark stiffness is less than 5 cm, poor running in the recording apparatus may occur. Further, the heat shrinkage rate by heat treatment at 150 ° C. for 1 minute is 5% or less, preferably 3.5% or less in both the machine direction and the cross direction. When the thermal shrinkage rate is greater than 5%, curling or running failure may occur before and after the heat fixing process in the recording apparatus.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these ranges. In the examples, “parts” and “%” indicate “parts by mass” and “% by mass” unless otherwise specified.

Example 1
(Formation of image receiving layer)
12 parts of synthetic hectorite clay mineral (trade name: Laponite RD, manufactured by Laporte Industries)
8 parts of polyurethane ionomer (trade name: LA-440A1, manufactured by Hoechst)
Oxazoline group-containing water-soluble polymer 5 parts (trade name: Epocross WS-500, manufactured by Nippon Shokubai Co., Ltd.)
The coating liquid obtained by mixing and stirring this composition (concentration 20%) was applied to one side of a synthetic paper (trade name: YUPO KAS200, manufactured by YUPO Corporation), and the coating amount after drying was 1 g / m ² . The electrophotographic transfer sheet was obtained by coating and drying as described above, free from tearing and deformation caused by water, and peeling of the toner.

[Measurement of Surface Electric Resistance Value of Electrophotographic Transfer Sheet] The obtained electrophotographic transfer sheet was stored for 10 hours under the following low humidity condition, normal humidity condition and high humidity condition, respectively, and then the surface electric resistance value was measured. The resistance was measured using an ohmmeter R12704 (manufactured by Advantest). The low humidity condition, normal humidity condition, and high humidity condition are as follows. The results are shown in Table 1. The low humidity condition, normal humidity condition, and high humidity condition are as follows.
Low humidity condition Temperature 10 ℃, relative humidity 30% RH
Normal humidity condition Temperature 20 ℃, relative humidity 65% RH
High humidity condition Temperature 30 ° C, relative humidity 85% RH

[Evaluation of recordability of electrophotographic transfer sheet] The obtained electrophotographic transfer sheet was stored under low humidity, normal humidity, and high humidity conditions for 10 hours, respectively, and then color copier LBP2040N (Canon The image quality was visually evaluated according to the following evaluation criteria. The results are shown in Table 2. The low humidity condition, the normal humidity condition, and the high humidity condition are the same as the measurement of the surface electric resistance value.
○: The toner transferability is good and the image density is sufficiently high. There are no practical problems and the quality is excellent.
Δ: The toner transferability is slightly uneven and the image density is inferior. There are practical problems.
X: The toner transferability is considerably uneven and the image density is remarkably inferior. There are practical problems.

[Evaluation of Toner Peeling by Immersion of Printed Part] The obtained electrophotographic transfer sheet was stored under normal humidity conditions for 10 hours, and then recorded with a color copier LBP2040N (manufactured by Canon Inc.) under a normal temperature environment. It was. Further, the print sample is immersed in water for 1 minute, then taken out, and the printed portion is rubbed with a finger. The degree of toner peeling was visually evaluated according to the following evaluation criteria. The results are shown in Table 3.
○: There is no toner peeling.
Δ: Toner peeling off somewhat and practically problematic.
X: Toner peeling off remarkably and problematic in practical use.

Examples 2-3
An electrophotographic transfer sheet was prepared in the same manner as in Example 1 except that the amount of the oxazoline group-containing water-soluble polymer was 2 parts by mass (Example 2) and 7 parts by mass (Example 3). Was created and evaluated.

Example 4
A coating solution obtained by mixing and stirring the following composition (concentration 20%) was applied to one side of a synthetic paper (trade name: YUPO KAS120, manufactured by YUPO Corporation), and the coating amount after drying was 3 g / m ^2. The electrophotographic transfer sheet was prepared by coating and drying so as to be evaluated in the same manner as in Example 1.
12 parts of synthetic hectorite clay mineral (trade name: Laponite S, manufactured by Laporte Industries)
8 parts of polyurethane ionomer (trade name: LA-440A1, manufactured by Hoechst)
7 parts of water-soluble polymer containing oxazoline group (trade name: Epocross WS-500, manufactured by Nippon Shokubai Co., Ltd.)

Example 5
A coating solution obtained by mixing and stirring the following composition (concentration 20%) was applied to one side of a synthetic paper (trade name: YUPO KAS120, manufactured by YUPO Corporation), and the coating amount after drying was 1 g / m ^2. The electrophotographic transfer sheet was prepared by coating and drying so as to be evaluated in the same manner as in Example 1.
10 parts of synthetic hectorite clay (trade name: Laponite S, manufactured by Laporte Industries)
Kaolinite clay (trade name: HG-90, manufactured by Huber) 5 parts polyurethane ionomer 5 parts (trade name: Hydran AP-40, manufactured by Dainippon Ink & Chemicals, Inc.)
3 parts of water-soluble polymer containing oxazoline group (trade name: Epocross WS-500, manufactured by Nippon Shokubai Co., Ltd.)

Comparative Example 1
In Example 1, an electrophotographic transfer sheet was prepared and evaluated in the same manner as in Example 1 except that the water-soluble polymer containing oisazoline group was not blended.

Comparative Example 2
Synthetic paper (trade name: YUPO KAS120, manufactured by YUPO Corporation) was used as an electrophotographic transfer sheet.

As is clear from Examples 1 to 5, the electrophotographic transfer sheet according to the present invention has a stable surface electric resistance value in a wide range of environments from low temperature and low humidity to high temperature and high humidity, and is excellent in toner transferability. It is an electrophotographic transfer sheet that has a high density, provides high-quality image quality, and does not tear or deform paper due to water and does not peel off toner, and is extremely useful in industry.

Claims (4)

  In an electrophotographic transfer sheet having a support made of synthetic paper containing polypropylene as a main component and an image receiving layer formed on at least one surface thereof, in the image receiving layer, a synthetic hectorite clay mineral and an oxazoline-based crosslink A transfer sheet for electrophotography, comprising a binder crosslinked with an agent.   The electrophotographic transfer sheet according to claim 1, wherein the binder contains a polyurethane ionomer resin.   The electrophotographic transfer sheet according to claim 1 or 2, wherein the blending ratio of the oxazoline-based crosslinking agent and the polyurethane ionomer resin is in the range of 1 to 100 parts by mass of the oxazoline-based crosslinking agent with respect to 100 parts by mass of the polyurethane ionomer resin. . The surface electric resistance value of the surface of the image receiving layer at a temperature of 10 ° C. to 30 ° C. and a relative humidity of 30% RH to 85% RH is in the range of 1 × 10 ⁶ to 1 × 10 ⁹ Ω. The electrophotographic transfer sheet as described.