JP3232514B2 - Transfer paper for electrophotography - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer paper for electrophotography and a color or monochrome electrophotography copying method capable of reproducing a high-quality image comparable to a photographic print using the transfer paper.

[0002]

2. Description of the Related Art Coated paper such as art paper and coated paper is used in elaborate printing and multicolor printing mainly using flat plate offset printing. This is due to the fact that the coated paper has a smooth surface, so that it has good contact with the ink film during printing, and the image is faithfully reproduced, and the image has high gloss and good color reproduction. However, if this coated printing paper is used as it is for electrophotographic transfer paper, problems such as image disturbance, double feeding and paper jam at the time of paper feeding, and blisters at the time of fixing occur (fizzle-like blisters). Conventionally, coated paper has rarely been used as transfer paper for electrophotography.

On the other hand, in recent years, in order to improve the image quality of electrophotography, the use of smooth coated paper has been considered to be advantageous for improving the image quality, as the particle size of the toner and the thickness of the transfer toner have been advanced in recent years. (Tokutani, Ota, "Non-impact Printer Paper", "Paper Pulp Technology Times, 27, No. 3 (198
4) p. 45-49 "). Also, for fixing with emphasis on image gloss and color reproduction, smooth coated paper is better in electrophotography as well as printing, so in order to solve the problem of coated paper for printing in electrophotography, In particular, various studies have been made to take advantage of the coated paper in color copying.

Japanese Patent Application Laid-Open No. Sho 62-1988877 discloses that the surface electric resistance of a transfer layer is adjusted to 8.0 × 10 ⁸ Ω or more at a temperature of 20 ° C. and a relative humidity of 85% so that image distortion at high temperature and high humidity is obtained. An electrophotographic transfer paper of a coated paper type in which the above is improved has been proposed. Japanese Patent Application Laid-Open No. 62-1988876 discloses a coated paper type electrophotographic apparatus in which the air permeability is adjusted to 4000 seconds or less to improve the transfer paper blister during thermal fixing of the toner on the coated paper. Transfer paper was proposed. However, when the electrophotographic transfer paper is used in a color copier, and the developed image on the photoreceptor is transferred a plurality of times and fixed by heat and pressure, the coated paper having the above-described transfer layer surface electric resistance and air permeability is obtained. However, transfer failure (hereinafter referred to as transfer unevenness) in which the solid portion of the image becomes particulate unevenness during transfer, and image gloss and gloss due to insufficient melting of the toner during fixing.
There is a problem that unevenness occurs.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned drawbacks and to provide a high-quality image comparable to a photographic print without causing transfer unevenness at the time of transfer and gloss unevenness at the time of fixing. It is an object of the present invention to provide a color and monochrome electrophotographic transfer paper which is excellent in running property and further has an electrophotographic copying method using the transfer paper.

[0006]

According to the present invention, a raw material is provided with a coating layer comprising a pigment and an adhesive and having a coating amount of 4 g / m ² or more per side on at least one surface of the raw material. 1
In an electrophotographic transfer paper made of a coated paper of 00 g / m ² , the surface electric resistance of the coated paper pretreated by the method of JISP8111 is in a range of 6 × 10 ⁹ to 1 × 10 ¹¹ Ω, and J. TAPPI No. An electrophotographic transfer paper, characterized in that the peak value of the larger pore diameter of the coated paper obtained by the mercury intrusion method according to No. 48 is in the range of 2.0 to 3.0 μm, and this transfer paper An electrophotographic copying method characterized by holding the image on a transfer film, transferring the developed image on the photoreceptor a plurality of times, and fixing the image by a heat and pressure fixing method.
The reason why the above-described transfer paper is pre-processed by the method of JISP8111 is as follows. The moisture content of paper varies greatly depending on the environmental conditions, and therefore the surface electrical resistance of the paper also varies greatly. Therefore, in order to define the surface electric resistance value of the transfer paper, it is necessary to perform a pretreatment and a test in a certain environment, and here, the standard conditions of JISP8111, namely, a temperature of 20 ° C. ± 2 ° C. and a humidity of 65 ± 2. %
Pre-processed.

[0007]

[Function] In order to perform good transfer by the electrophotographic copying method,
It is necessary to provide a sufficient electric field intensity necessary for transfer between the photoreceptor and the transfer paper. Specifically, the current value (It) flowing through the transfer corotron wire is adjusted to adjust the current value (Id) to the transfer film. Is kept constant. In particular, in a copying machine and a printer of a dry color electrophotographic system, since the developed image on the photosensitive member is transferred a plurality of times, the transfer film potential in the final color transfer is higher than that in the transfer of the first color. Therefore, in order to make the electric field intensity between the photosensitive member and the transfer paper equal to the electric field intensity at the time of the transfer of the first color in order to perform the transfer of the final color, it is necessary to set the It at the time of the transfer of the final color.
Is a large value compared to It at the time of transfer of the first color. Therefore, the transfer paper needs to be examined so that transfer unevenness does not occur for a wide range of It.

The present inventors have conducted intensive studies to suppress the transfer unevenness and the gloss unevenness. TAPP
I No. Use a coated paper for electrophotography in which the peak value of the larger void diameter of the coated paper by the mercury intrusion method according to No. 48 is in the range of 2.0 to 3.0 μm, preferably 2.0 to 2.7 μm. As a result, it has been found that transfer unevenness can be improved for the above-mentioned wide range of It. If this peak value exceeds 3.0 μm, more precisely, 2.7 μm
When m exceeds m, transfer unevenness occurs as the value of It is increased. This is considered to be due to discharge occurring inside the coated paper. Therefore, in order to improve such transfer unevenness, this peak value should be 3.0 μm
Hereinafter, it is necessary to increase the electric breakdown strength of the coated paper by setting a small value, preferably 2.7 μm or less. However, if the peak value is too small, there is a drawback that the stiffness of the paper becomes weak and a trouble occurs when the paper is passed. Therefore, the lower limit of the peak value is preferably 2.0 μm or more.
In addition, the peak value of the larger void diameter of the coated paper has the following meaning. Usually, the void volume distribution curve relating to the void diameter of the coated paper has two peaks. Among them, the peak with the larger void diameter is derived from the void in the raw material layer, and the peak with the smaller void diameter is derived from the void in the coating layer. In the present invention, it has been found that transfer unevenness can be suppressed by setting a value of a peak having a larger void diameter derived from a void diameter of a raw layer of a coated paper within a certain value.

Regarding the gloss and unevenness at the time of fixing,
At least 4 g / m coating amount per side^TwoCoating layer above
With a basis weight of 85 to 100 g / m^TwoElectrophotographic coated paper
Have been found to be improved by using. Paint
100g / m basis weight of industrial paper^TwoExceeds the gross
Unevenness or in extreme cases the toner may come off
Sometimes. This is due to poor thermal conductivity during fixing
It is possible to fuse and fix toner sufficiently on coated paper
Probably because it cannot. In addition, the basis weight of the coated paper is 85
g / m^TwoIf it is less than, fixing is sufficient, but when fixing
And then wrap around the fixing roll. So this
To improve the above gross unevenness by eliminating these disadvantages
Has a coating amount of 4 g / m per side.^TwoWith the above coating layer
E, basis weight 85-100g / m^TwoUsing electrophotographic coated paper
Improves thermal conductivity and ensures sufficient fixing
Need to be In addition, the coating amount is 4 g / m^Two
If less, the fiber of the raw fabric cannot be covered sufficiently, so the fixed image
It is difficult to obtain high quality images
Can not. The basis weight of the coated paper is 85 to 100 g / m. ^Two
30g / m in the range of^TwoOver, the waist of the paper is weak
Disadvantages, such as trouble with paper passing

The configuration of the transfer paper according to the present invention will be described in more detail. As the pulp used as the raw material of the transfer paper, chemical pulp, mechanical pulp, waste paper pulp and all other conventionally known pulp can be used. Also,
Either a neutral paper formulation or an acidic paper formulation may be used. Also,
As the filler to be used, all known fillers such as talc, kaolin, calcium carbonate, titanium dioxide and the like can be used.

Since the peak value of the larger gap diameter of the coated paper is derived from the gap of the raw layer, the gap diameter in the raw layer is 2.0 to 3.0 μm, preferably 2.0 to 3.0 μm. 0.7 μm
Need to be adjusted. The measurement of the pore diameter of the coated paper is described in J. Org. TAPPI No. According to the mercury intrusion method according to No.48. The outline of this method will be described below. The principle of the measurement method is that the volume of mercury injected into the pores (voids) of the sample is measured with a dilatometer and automatically recorded as a function of pressure. The principle of measurement is Kelvin with respect to pore radius and mercury surface tension, contact angle and pressure.
Based on the formula. The applied pressure and the pore radius are in inverse proportion, and the pressure is converted into the pore radius from this formula, and the cumulative curve of the pore volume and the pore volume distribution curve with respect to the pore radius are obtained. As a method for adjusting the gap diameter of the coated paper, a desired gap diameter can be obtained by filling gaps in the raw material with a substance other than fibers. For filling, clay, talc, titanium white, calcium carbonate, etc. can be used, but the amount of the mixture is determined with sufficient care in consideration of blistering during fixing, lowering of paper stiffness, etc. is necessary.

Also, by beating the fibers to make them fluffy or to make them into fine fibers (single fibers), the voids in the raw material can be filled to obtain the desired void diameter. However, if the fibers are beaten too hard, the curl after papermaking becomes large, the paper becomes stiff, and the opacity is reduced, thereby deteriorating the suitability for an electrophotographic copying machine. Therefore, when applying this method, it is necessary to pay attention to the degree of beating, or to devise a method such as blending fibers that have been strongly beaten with fibers that have been subjected to regular beating to make base paper. . Also, increase the pressure between the press rolls,
The density of the raw material can be increased.

[0013] Further, by passing between a rigid roll such as a super calender or a gloss calender many times and an elastic nip, a smoothing treatment is performed, and a gap in the raw material is crushed to obtain a desired gap diameter. it can.
This method can be applied to the coated paper, but if the calendering after the coating is performed excessively, so-called “calendar burn” occurs, and the gloss of the coated layer is reduced. Images cannot be obtained. Further, there is a disadvantage that the stiffness of the paper is weakened, and it is desirable to perform an appropriate calendering process. In addition, the method of adjusting the gap diameter in the raw material of the present invention,
It is not limited to the above method.

The material of the coating layer has a surface electric resistance value of 6 × 1.
As long as it is in the range of ⁰⁹ to 1 × 10 ¹¹ Ω and is applicable to electrophotography, it can be used irrespective of its type. When the surface electric resistance value is lower than 6 × 10 ⁹ Ω, transfer loss occurs particularly at high humidity, and when the surface electric resistance value exceeds 1 × 10 ¹¹ Ω, image disturbance due to peeling discharge from the photosensitive material especially at low humidity and unevenness during transfer. Is likely to occur, which is not preferable. The pigment, which is the main component of the coating, has an average particle size of 1.5 μm for smoothing the coated surface by using a super calendar after coating.
m or less, preferably 1.0 μm or less, the transfer rate of the toner is high at the time of transfer of the toner layer, the electrical resistance is high in order to prevent the disturbance of the image, and the blister at the time of fixing is reduced. To prevent this, it is desirable to provide air permeability. If the average particle diameter exceeds 1.5 μm, the white paper gloss does not increase even if the smoothing treatment is performed, and the smoothing effect cannot be sufficiently obtained, or the air permeability tends to decrease. Known pigments include heavy calcium carbonate, light calcium carbonate, calcined clay, lithopone, zinc oxide, titanium dioxide, barium sulfate, urea resin, kaolin clay, sericite, siegrite, talc, and other known pigments. Or a combination of two or more, but pigments with water of crystallization, or pigments with a flat crystal structure,
It is better to avoid using alone because there is a concern that air permeability may be reduced and blisters may be generated.

The adhesive has a strong adhesion between the pigment and the raw material,
A water-soluble adhesive, emulsion, or latex having low blocking properties can be used.However, in order to improve the transfer of the toner layer, the fluctuation of the electric resistance on the paper surface in a small portion should be small and high. In order to prevent a decrease in electric resistance under humidity, it is desirable not to use a component having a low electric resistance such as an emulsifier or to reduce the amount of use as much as possible. For example, it is possible to use a soapless self-crosslinking acrylic emulsion that is emulsified without an emulsifier by containing a resin component of a self-crosslinking acrylic resin system and containing less than 5 mol% of a carboxylic acid with respect to the acrylic resin. it can. Carboxylic acid, acrylic acid, methacrylic acid, itaconic acid, maleic anhydride is preferred,
If it is used in an amount exceeding 5 mol%, the electric resistance value is undesirably reduced. There are various types of crosslinking reactions, such as a crosslinking reaction between a carboxyl group and an epoxy resin, an amide self-crosslinking reaction, a crosslinking reaction between a carboxyl group and a melamine resin, and a crosslinking reaction between a hydroxyl group and a melamine resin. Any type may be used.

In addition, an amphoteric latex which uses a small amount of an emulsifier can be used as an adhesive. For example, aliphatic conjugated diolefin monomers such as 1,3-butadiene, 2-methyl-1,3-butadiene, 2-chloro-1,3 butadiene; styrene, α-methylstyrene,
Monoolefinic monomers such as monochlorostyrene, acrylic acid ester, methacrylic acid ester, and acrylonitrile; ethylenically unsaturated acid monomers such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid, crotonic acid, and cinnamic acid; and methyl Monomer composed of ethylenically unsaturated amine monomers such as aminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, and dibutylaminoethyl (meth) acrylate Is a latex obtained by polymerizing under the condition that the unsaturated acid monomer and the unsaturated amine monomer are not simultaneously present in the polymerization system when the polymerization is carried out using 1% by weight or less of an emulsifier with respect to all the monomers. Volatile al Stabilized by Li substances, pH 3.
Some of them cause gelation at 5 to 8.5. When this amphoteric latex and pigment are mixed, applied to paper, and dried, the alkaline substance is volatilized and gels, so that the adhesion with the pigment is improved and the electrical resistance of the obtained coating film is considered to be improved. Can be

These soapless self-crosslinking acrylic emulsions and amphoteric latexes can be used not only alone but also in a mixture, and can be used in a water-soluble manner as long as the electric resistance is not excessively reduced. Resins, for example, polyvinyl alcohol, starch, methylcellulose, hydroxyethylcellulose, styrene-acrylic resin, and the like can be used as a mixture. In addition, a dye or a colored pigment may be added to the paint to adjust the color tone, or a fluorescent dye may be added to increase the visual whiteness. Furthermore, to facilitate paint preparation,
Dispersants and defoamers can also be added.

The weight ratio of the pigment to the adhesive in the paint is 9
The range of 5/5 to 60/40 is desirable, but in particular, 95/60/40.
A range of 5 to 70/30 is desirable. Pigment ratio is 95
If the amount exceeds 10% by weight, the strength of the coating film is weakened, and not only the image gloss is reduced, but also a trouble may be caused in the manufacturing process. When the compounding ratio of the pigment is less than 60% by weight, sufficient white paper gloss cannot be obtained even with a smoothing finish. As a coating method, a general coating method, for example, a blade coating method, an air knife coating method, a roll coating method, a bar coating method, or the like can be used.

[0019]

The present invention will be described more specifically with reference to the following examples and comparative examples. In the following examples, parts represent parts by weight. (Example 1) A raw material having a basis weight of 81 g / m ² was subjected to a super calender treatment, and styrene butadiene rubber (SB
R) and polyvinyl alcohol (PVA) at a compounding ratio of 69
Parts / 31 parts of adhesive and 7 parts by weight of kaolin and charcoal
The coating amount after drying of a coating material composed of 1 part / 29 parts of a pigment and having a mixing ratio of the pigment and the adhesive of 87 parts / 13 parts is 15 g / m ^{2 on} the felt surface of the raw material, and 3. 5g /
After coating with a lab coater so as to obtain m ² , a transfer paper for electrophotography was obtained by performing a super calender treatment.

(Example 2) A raw material having a basis weight of 66.5 g / m ² was subjected to a super calendering treatment, and was coated and super calendered in the same manner as in Example 1 to obtain an electrophotographic transfer paper. Was.

(Embodiment 3) Under the conditions of Embodiment 1, the coating amount after drying on the felt surface is from 15 g / m ² to 10 g / m ^2.
The transfer paper for electrophotography was obtained with a reduction in m ² .

(Embodiment 4) Under the conditions of Embodiment 1, the coating amount after drying on the felt surface is from 15 g / m ² to 4 g / m ^2.
The transfer paper for electrophotography was obtained by reducing it to ² .

Example 5 Transfer paper for electrophotography was obtained by changing the blending ratio of the adhesive SBR and PVA from 69 parts / 31 parts to 85 parts / 15 parts in the conditions of Example 1.

(Example 6) A raw calender having a basis weight of 82.4 g / m ² was subjected to a super calendering treatment, and the conditions of Example 1 were changed to a pigment obtained by replacing all of the charcoal with kaolin. In the same manner as in Example 1, an electrophotographic transfer paper was obtained.

(Example 7) Commercially available Fuji Xerox M
Example 1 Super-calendering of paper stock
Coating and supercalendering were performed under the same conditions as in Example 1 to obtain an electrophotographic transfer paper.

Example 8 Commercially available Fuji Xerox M
Coating on a raw paper for paper under the same conditions as in Example 1,
A calendering process was performed to obtain an electrophotographic transfer paper.

(Comparative Example 1) An adhesive having a blending ratio of SBR and PVA of 69 parts / 31 parts and a blending ratio of kaolin and charcoal of 71 parts / 29 parts in a raw material having a basis weight of 82.4 g / m ^2. Of the coating material having a mixing ratio of 87 parts / 13 parts of the pigment and the adhesive, and the coating amount after drying is 1% on the felt surface of the raw material.
The coating was performed by a lab coater so as to be 5 g / m ² and 3.5 g / m ^{2 on} the wire surface, and thereafter, a transfer paper for electrophotography was obtained without performing super calendar treatment.

(Comparative Example 2) An original paper for printing paper sunflower commercially available from Oji Paper Co., Ltd. was coated in the same manner as in Comparative Example 1, and then subjected to a super calender treatment to obtain an electrophotographic transfer paper. I got

Comparative Example 3 Commercially available L manufactured by Fuji Xerox Co., Ltd.
Coating amount after drying a coating material used in Comparative Example 1 to raw for paper, 30 g / m ² on the felt surface of the raw, lab coater so that 3.5 g / m ² on the wire surface Coating,
Thereafter, a super calendar treatment was performed to obtain an electrophotographic transfer paper.

Comparative Example 4 Commercially available L manufactured by Fuji Xerox Co., Ltd.
Coating amount after drying a coating material used in Comparative Example 1 to raw for paper, 3 g / m ² on the felt surface of the raw, lab coater so that 3.5 g / m ² on the wire surface Coating,
Thereafter, a super calendar treatment was performed to obtain an electrophotographic transfer paper.

(Comparative Example 5) The raw material used in Comparative Example 1 was dried using SBR as an adhesive, charcoal char as a pigment, and a coating material having a mixing ratio of 87 parts / 13 parts of the pigment and the adhesive. the coating amount of later, 15 g / m ² on the felt surface of the raw, and coated in a laboratory coater so that 3.5 g / m ² on the wire surface, then, for electrophotographic transfer performs super calendar treatment I got the paper.

(Comparative Example 6) The raw material used in Comparative Example 1 was replaced with the coating material of Comparative Example 1 containing 0.6 g / anionic conductive resin.
Coating was performed in the same manner as in Comparative Example 1 with the addition of m ² , and then a super calendar treatment was performed to obtain an electrophotographic transfer paper.

(Comparative Example 7) The raw material used in Comparative Example 1 was replaced with the coating material of Comparative Example 1 containing 1.4 g / anionic conductive resin.
Coating was performed in the same manner as in Comparative Example 1 with the addition of m ² , and then a super calendar treatment was performed to obtain an electrophotographic transfer paper.

(Comparative Example 8) Commercially available Fuji Xerox M
Coating was carried out in the same manner as in Comparative Example 1 using a paper web to obtain an electrophotographic transfer paper.

(Comparative Example 9) Coating paper (thick mouth) manufactured by Fuji Xerox Co., Ltd. was used and coated in the same manner as in Comparative Example 1 to obtain an electrophotographic transfer paper.

(Comparative Example 10) A commercial printing coated paper OK special art manufactured by Oji Paper Co., Ltd. was used as an electrophotographic transfer paper.

[0037] was used (Comparative Example 11), commercially available Canon Sales Co., Ltd. color electrophotographic coating paper coat type for the paper pixel.

For the papers listed in Examples 1 to 8 and Comparative Examples 1 to 11, the basis weight (g / m ² ), the thickness (μm),
J. TAPPI No. Peak value (μm) of the larger pore diameter of the coated paper by the mercury intrusion method according to No. 48,
Transfer surface electric resistance (Ω), transfer current (Itμ)
The image quality, gloss / unevenness at the temperature of the silicone-coated rubber roll, and running properties in A) were measured and evaluated by the following methods, and the results are shown in Tables 1 and 2.

[0039]

[Table 1]

[0040]

[Table 2]

Basis weight: Measured according to the method of JISP8124. Thickness: Measured by the method of JISP8118. Material void diameter mode: CARLO ER as measuring instrument
POROSIME manufactured by BA INSTRUMENTS
Using TER 2000, MACRO PORE 120, TAPPI No. The mode value of the pore diameter was measured by a mercury intrusion method according to No.48. Surface electric resistance value: Using a room temperature measurement box (RC-02) and a super insulation meter (R-503) manufactured by Kawaguchi Electric Works, set the applied voltage to 100 V, and place the test piece in front of the specimen by the method of JISP8111. The transfer surface was measured by the method according to the surface resistivity of JISC2122 under the same conditions as in the pretreatment. Image quality of each transfer current value: Using a color electrophotographic copying machine (CLC500 manufactured by Canon Inc.), the transfer current value (It) flowing through the transfer contron wire by an external power supply
Was changed to form a transfer image composed of 200 lines and 200 lines (200 lines / inch) on the transfer surface using a magenta toner, and then a fixed image was obtained. In the obtained image, the input density is X-Rite404A (manufactured by X-Rite).
Solid portions of 31 to 1.87 were visually evaluated. The test paper was pretreated by the method of JISP8111. The meanings of the symbols in the table are as follows. A: Transfer unevenness and other image defects are almost nonexistent. ：: There are some transfer unevenness and other image defects,
It is not noticeable visually. Δ: There are uneven transfer and other image defects, which are slightly noticeable visually. X: Transfer unevenness and other image defects are extremely large, and are clearly recognized visually. XX: Poor transfer and other image defects are observed. Gross / Mura: Using a color electrophotographic copier (CLC500, manufactured by Canon Inc.), a color 200-line parallel transfer image was obtained on the transfer surface, and then the temperature of the silicon rubber-coated roll of the heat-pressing type fixing device was measured. At 150 ° C. and 160 ° C. to obtain a fixed image. The whole of the fixed image was visually evaluated. The test paper was pretreated by the method of JISP8111. The meanings of the symbols in the table are as follows. ：: No gloss or unevenness. Δ: There is unevenness in gloss, and it is slightly noticeable visually. X: The gloss unevenness is very large, and is clearly recognized visually. Runnability: ：: No phasor-wrapped jam occurs. Δ: Jam occurred due to phasor winding about 1/10 of the total running number. ×: Jam occurred with 巻 き phasor winding of the total running number. XX: The total number of running sheets.

[0042]

According to the present invention, by adopting the above-mentioned structure, a color and monochrome high-quality image comparable to that of a photographic print can be obtained by an electrophotographic copying method without transfer unevenness at the time of transfer and gloss unevenness at the time of fixing. Now you can do it.

──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Koichi Makiyama 2274 Hongo, Ebina-shi, Kanagawa Fuji Xerox Co., Ltd.Ebina Office (72) Inventor Shinichi Nagasawa 1-10-6 Shinonome, Koto-ku, Tokyo Oji Paper Stock (72) Inventor Shigesaku Uechi 4-57-5 Ginza, Chuo-ku, Tokyo Oji Paper Co., Ltd. (56) References JP-A-4-88354 (JP, A) JP-A-1-245265 (JP, A) JP-A-3-294600 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 7/00 101

Claims (2)

(57) [Claims] On at least one surface of 1. A raw, with a coating weight 4g / m ² or more coating layers per surface consisting of a pigment and an adhesive, basis weight 85~100g / m ² of coated paper In the electrophotographic transfer paper, the coated paper pretreated by the method of JISP8111 has a surface electric resistance value of 6 × 10
⁹ to 1 × 10 ¹¹ Ω. TAPPI
No. 48. A transfer paper for electrophotography, wherein the peak value of the larger pore diameter of the coated paper by mercury intrusion method according to No. 48 is in the range of 2.0 to 3.0 μm. 2. The electrophotographic copying method according to claim 1, wherein the transfer paper for electrophotography according to claim 1 is held on a transfer film, a developed image on a photoreceptor is transferred a plurality of times, and is fixed by a heat and pressure fixing method. Method.