JPS62198877A - Electrophotographic transfer paper - Google Patents

Abstract

PURPOSE:To obtain a copy having a high gloss and high image quality without having the disturbance of the image in the stage of transfer by providing a transfer layer having <=2.0mum center line average height of surface on at least one face of base paper and adjusting the surface electric resistance of the transfer layer to >=8.0X10<8>OMEGA at 20 deg.C and 85% relative humidity. CONSTITUTION:A coating compd. which consists essentially of a pigment having high electric resistance and is compounded with an adhesive agent is coated on at least one face of the base paper and the surface thereof is smoothed. The surface resistance of the transfer layer is adjusted to >=8.0X10<8>OMEGA at 20 deg.C and 85% humidity (RH). The pigment having the high electric resistance is selected from, for example, heavy calcium carbonate, light calcium carbonate, etc. The smoothing treatment is executed by passing the base paper many times between a rigid roll and elastic roll of a super calender of gloss calender and is so adjusted that the center line average height of the surface attains <=2.0mum, more preferably <=1.5mum in order to obtain the substantial image surface gloss.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to electrophotographic transfer paper, and is particularly useful for high-quality copies in monochrome and color electrophotographic copying machines that reproduce image quality comparable to photographs and printing. The present invention relates to an electrophotographic transfer paper suitable for obtaining.

[Prior Art] Coated papers such as art paper and coated paper are used in elaborate printing and multicolor printing, where planar offset printing is the mainstream. This is because the coated paper has a smooth surface, which allows for good contact with the ink film during printing, resulting in faithful reproduction of images, high gloss, and good color reproduction.

Regarding the suitability of coated paper for electrophotography, there is a study by Tsukatani et al. They argue that coated paper is physically smooth and adheres uniformly to the photoreceptor, so theoretically it should be possible to obtain a clean toner transfer image, but they have not actually applied it to existing equipment. In some cases, the image becomes rough (Tsukatani, Ota:
Non-impact printer paper, paper pulp technology times 2
7, No. 64 (19B4>31-36>. In fact, even if coated printing paper is used for electrophotography, there is no advantage in image quality, and it is rarely used.

The inventors have found that a major drawback in terms of image quality in electrophotography using coated paper for printing is that disturbances during the transfer of toner images from the photoreceptor to the paper are This phenomenon is caused by a temperature of 20℃ and humidity (
This was particularly noticeable under high humidity conditions, with an example of RH) of 85%. The cause of this is mainly due to the electrical properties of the coating material on the surface of the coated paper (it turned out that this is because the surface resistance of the paper is low).

On the other hand, regarding methods for improving image quality in electrophotography, Tsukatani et al. suggest reducing the toner particle size and thinning the transferred toner layer in comparison with the printing process (Tsukatani et al.).

Ota: Non-impact printer paper, Paper and Pulp Technology Times, 27. No. 3 (1984) 45-49).

In these technical aspects, if the problems of coated paper for printing in electrophotography can be solved, the use of smooth coated paper is considered to be advantageous in terms of image quality. Furthermore, it has been confirmed that smooth coated paper is better for electrophotography as well as for printing when fixing images with emphasis on gloss and color reproduction.

Transfer paper for electrophotography that is closest to coated paper is transfer paper for magnetic component development (Japanese Patent Publication No. 58-26026, Japanese Patent Publication No. 57-24716, Japanese Patent Publication No. 57-53592).
No., Special Publication No. 57-55139).

This transfer paper is made by coating a base paper with a paint mainly consisting of a high electrical resistance resin in order to improve the image disturbance caused by the low electrical resistance of the magnetic component developer. In order to resemble paper, the amount of coating is small and the surface is low and smooth, making it unsuitable for the above-mentioned high image quality applications. The same pigments used in the coating for coated printing paper are also included in the coating for this transfer paper.

However, in the case of coated paper for printing, large amounts of pigment are blended mainly for the purpose of smoothing, whereas pigments are blended to resemble plain paper, and when blended in large amounts, the effect of high electrical resistance resin The amount of pigment added in the paint is significantly lower than that of coated paper for printing, in order to reduce the Therefore, simply increasing the coating amount of paint on this transfer paper does not provide the same level of smoothness as coated paper for printing, and also causes problems such as blocking between the sheets, making it unsuitable for use as transfer paper for electrophotography. I can not use it.

[Problems to be Solved by the Invention] An object of the present invention is to improve the drawbacks of the prior art described above, and to provide a coating for electrophotographic transfer that eliminates image disturbance during transfer in electrophotography and provides high-quality copies. Our goal is to provide paper.

[Means for Solving the Problems] In order to achieve the above-mentioned problems, the present invention provides an image receiving layer having a surface center line average roughness of 2.0 μm or less on at least one side of a base paper, and a transfer layer. Surface electrical resistance at temperature 20'
C. An electrophotographic transfer paper characterized in that the relative humidity (RH>85%) is adjusted to 8.0×10 8 Ω or more.

Regarding the influence of paper on the color reproduction of printing, see J.
A, C, Yu Ie has a higher paper surface cross and a lower ink absorption, the less the ink color will deteriorate, and compared to uncoated paper, coated paper can produce sharper images. (J, A, C, YuIe: pri
nciplesofQOIOrReprodu
ction.

JOHN WILEY & 5ONS, INC.
.

1967).

The present inventors evaluated the color deterioration of color toner for electrophotography using commercially available coated printing paper, high-quality paper, and prototype coated paper.As with printing, coated paper was superior to high-quality paper. It was confirmed that there was little color deterioration. For these papers, use the GARDNER gloss meter GARDNER GLO.
Measured using 3SGARDII. In addition, the center line average roughness was measured using a universal surface profile measuring device 5 manufactured by Kosaka Laboratory Co., Ltd.
JIS using urfcorder 5E-3C
According to the method of BO601, the cutoff value is 0.8m and the measured length is 871! I11 was measured, and the relationship between loss and center line average roughness was obtained as shown in FIG. From this result, for cloth, the boundary between coated paper and high-quality paper with less color deterioration is 1
0%, but matte-finish coated paper and high-quality paper exist near this area, making it difficult to distinguish between the two, whereas the two can be clearly distinguished by taking the boundary value of 2 μm for the center line average roughness. I understand.

In addition, in order for the color toner to develop sufficiently, the toner must be sufficiently melted during fixing, which will result in a high image cross, so if the cross of the paper itself is too low, the uneven cross in the copy will become undesirable. .

From this point of view, the center line average roughness of the paper surface is 20% for gloss.
The thickness is preferably 1.5 μm or less.

In the electrophotographic transfer paper of the present invention, a paint containing a pigment with high electrical resistance as a main ingredient and an adhesive is coated on at least one side of the base paper to smooth the surface, and the surface electrical resistance of the transfer layer is adjusted by temperature. 8.0×108 at 20℃, humidity (R)-1>85%
It can be obtained by adjusting it so that it is Ω or more.

The pigment, which is the main component of the paint, has an average particle size of 1.5 because the coated surface is smoothed using a super calender etc. after coating.
Fine particles of less than μm, preferably less than 1.0 μm,
In addition, it is desirable to have a high electrical resistance in order to have a high toner transfer rate and prevent image disturbance when transferring a single layer of toner.

If the average grain size exceeds 1.5 μm, the center line average roughness tends not to be reduced even after smoothing treatment, which is undesirable. Pigments with high electrical resistance can be selected from, for example, heavy calcium carbonate, light calcium carbonate, calcined clay, lithopone, zinc oxide, titanium dioxide, barium sulfate, urea resin pigments, and the like. Kaolin clay, sericite, gicrite, talc, etc. containing crystal water have low electrical resistance and are not preferred.

Water-soluble adhesives, emulsions, and latexes that have strong adhesion to pigments and base paper and have low blocking properties can be used, but in order to improve the transfer of the toner layer,
In order to suppress small fluctuations in electrical resistance on the paper surface and to prevent a decrease in electrical resistance under high humidity, components with low electrical resistance such as emulsifiers should not be used or should be used in as little amount as possible. desirable. For example, a soapless self-crosslinking acrylic emulsion can be used in which the resin component is a self-crosslinking acrylic resin and the emulsion is made without an emulsifier by containing less than 5 mol % of carboxylic acid based on the acrylic resin. Preferred carboxylic acids are acrylic acid, methacrylic acid, itaconic acid, and maleic anhydride, but if they are used in excess of 5 mol %, the electrical resistance value decreases, which is not preferred. 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, and any type may be used.

Also, amphoteric latex with a small amount of emulsifier can be used as an adhesive. For example, 1,3-butadiene,
2-methyl-1,3-butadiene, 2-chloro-1,3
- Aliphatic conjugated diolefin monomers such as butadiene, monoolefin monomers such as styrene, α-methylstyrene, monochlorostyrene, acrylic esters, methacrylic esters, acrylonitrile, acrylic acid, methacrylic acid, itaconic acid, fumaric acid, Ethylenically unsaturated acid monomers such as crotonic acid and cinnamic acid, and methylaminoethyl (meth)acrylate, t-butylaminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, dibutylaminoethyl (meth)acrylate, dibutyl When a monomer consisting of an ethylenically unsaturated amine monomer such as aminoethyl (meth)acrylate is polymerized using an emulsifier of 1% by weight or less based on the total monomer, the unsaturated acid monomer and the unsaturated amine monomer are polymerized. There are latexes obtained by polymerization under conditions that do not simultaneously exist in the polymerization system, are stabilized by volatile alkaline substances such as ammonia, and cause gelation at 113.5 to 8.5.

When this amphoteric latex and pigment are mixed, applied to paper, and dried, gelation occurs when the alkaline substance evaporates.
It is thought that it has good adhesion with pigments and improves the electrical resistance of the resulting coating film.

In addition, these soapless self-crosslinking acrylic emulsions and amphoteric latexes can be used not only individually, but also in combination, or with water-soluble resins such as polyvinyl alcohol, starch, etc., as long as they do not inhibit high electrical resistance. It can be used in combination with methylcellulose, hydroxyethylcellulose, styrene-acrylic resin, etc.

In addition, dyes and colored pigments may be added to the paint to adjust the color tone, and fluorescent dyes may be added to improve visual whiteness. Dispersants and antifoaming agents can also be added to facilitate paint preparation.

The blending ratio of pigment and adhesive in the paint is 9515 to 60/40
The average roughness of the center line is preferably 2 μm by smoothing the finish.
(blank paper cloth 10% or more). In particular, for 9515-70/30, the center line average roughness is 1.5μ
It is more desirable because it can be made TrL (20% or more blank paper cloth).

When the pigment blending ratio exceeds 95%, the strength of the coating film decreases, causing problems in production and the toner fixing properties after recording are reduced. Moreover, if it is less than 60%, there is a drawback that even if a smooth finish is applied, sufficient center line average roughness and blank paper cannot be obtained.

If it is less than 40%, there are drawbacks such as blocking between sheets and deterioration of writability.

The coating amount is preferably 5 to 30 g/Td per side.

If the coating amount is less than 5 g/m, it will not be possible to obtain the target electrical resistance, center line average roughness and white paper cross.
If it exceeds 30 g/Tri, the stiffness of the paper becomes weak, causing problems in paper passing properties, and there are disadvantages in that the curling property becomes thick.

As the coating method, general coating methods such as blade coating, air knife coating, roll coating, bar coating, etc. can be used.

The smoothing treatment can be performed by passing the material through the nip between a rigid roll and an elastic roll many times using a super calender or a cross calender.

The smoothing process is performed using JISBO to obtain sufficient image glossiness.
601, the center line average roughness of the surface is 2.0 μm or less,
Desirably, it is necessary to adjust the thickness to 1.5 μm or less.

In order to obtain the required center line average roughness, it is not possible to control it only by the smoothing process, but it is also necessary to consider the pigment particle size, blending ratio, coating amount, and coating method.

As the base paper, acidic or neutral high-quality paper or medium-quality paper can be used. However, in order to provide suitability for electrophotographic copying machines such as runnability and curling properties, the blending, preparation, and manufacturing conditions of the raw materials must be adjusted according to known methods. Method (Special Publication No. 55-47385, Special Publication No. 57-812)
Paper controlled by No. 70) is preferable.

[Examples] The present invention will be explained in detail below using Examples and Comparative Examples. In the following examples, parts represent parts by weight.

°Example 1 Hardwood bleached kraft pulp (LBK) with a freeness of 460cc
P) Light calcium carbonate (Brilliant 1500゜Average particle size 0.15 μm, manufactured by Shiraishi Kogyo Co., Ltd.>90 parts, ampholytic obtained by polymerizing latex of styrene:butadiene:methacrylic acid=60 parts:37 parts:3 parts, and then copolymerizing 2 parts of diethylaminoethyl methacrylate. 8 parts latex and oxidized starch (Ace A.

The coating amount after drying of the paint consisting of 2 parts (manufactured by Tamago Cornstarch Co., Ltd.) is felt side (F side) / wire side (W side) = 1
Coating paper was coated with a blade coater at a concentration of 5/15 g/m (mugi) and smoothed with a super calendar to obtain copy paper.

Example 2 Hardwood bleached kraft pulp (LBK) with a beating degree of 460cc
P) Paper was made by adding 12 parts of talc, 2 parts of starch, 1.5 parts of rosin sizing agent and 1 part of sulfuric acid to 100 parts 6
85 parts of light calcium carbonate (Brilliant'l 500° average particle size 0.15 μm, manufactured by Shiraishi Kogyo Co., Ltd.), styrene:butadiene:methacrylic acid = 60 parts: 37 parts: 3 parts latex on both sides of 5g/Td high-quality paper. and 13 parts of an amphoteric latex obtained by copolymerizing 2 parts of diethylamine ethyl methacrylate and oxidized starch (Ace A).

After applying the paint consisting of 2 parts (manufactured by Tamago Corn Starch Co., Ltd.) using an air knife coater so that the coating I after drying is 15/15 g/m on the F side/W side, smoothing it with a super calender and copying. I got the paper.

Example 3 Both sides of the high-quality paper used in Example 1 were coated with 58 parts of heavy calcium carbonate (NS-1000, average particle size 1.17 μm, manufactured by Nitto Funka Co., Ltd.) and wet-pulverized calcium carbonate (car-top 90 parts).
．． Average particle size is 0.6μ.

29 parts (manufactured by Fuji Kaolin Co., Ltd.), 8 parts of Soapless self-crosslinking acrylic emulsion (Jurimar-3EKIO1, manufactured by Nippon Tsumugi Co., Ltd.), and polyvinyl alsil (Poval 11)
7. After applying the paint consisting of 5 parts (manufactured by Kuraray Co., Ltd.) using an air knife coater so that the coating amount after drying is F side/W side = 13/13g/TIt, smoothing treatment was performed using a super calender and the copy paper was coated. I got it.

Example 4 On both sides of the high-quality paper used in Example 1, 58 parts of light calcium carbonate (Brilliant 1500, average particle size 0.15 μm, manufactured by Shiraishi Kogyo Co., Ltd.) and wet-pulverized calcium carbonate (Cargotal 90, average particle size 0) were added. .6 μm, manufactured by Fuji Kaolin Co., Ltd.) 29
Section, Soapless self-crosslinking acrylic emulsion (Di1
Rimmer 3EK101. The coating amount after drying of the paint consisting of 8 parts (manufactured by Nippon Pure Chemical Industries) and 5 parts of polyvinyl alcohol (Poval 117. manufactured by Kuraray Co., Ltd.) is F side / W side = 13 / 13
After coating with an air knife coater so as to give a coating weight of 1 q/m, copying paper was smoothed using a super calender to obtain 1 q of copy paper.

Example 5 45 parts of light calcium carbonate (Brilliant 1500, average particle size 0.15 μm, manufactured by Shiraishi Kogyo Co., Ltd.) and wet-pulverized calcium carbonate (Carbicle 90, average particle size 0.6 μm) were coated on both sides of the high-quality paper used in Example 1. , manufactured by Fuji Kaolin Co., Ltd.) 20
After drying a paint consisting of 30 parts of Soapless self-crosslinking acrylic emulsion (Jurimar 3EK101, manufactured by Nippon Pure Chemical Industries, Ltd.) and 5 parts of polyvinyl alcohol (Poval 117, manufactured by Kuraray Co., Ltd.), the amount of coating after drying is F side / W side = 7/l/
After applying with an air knife coater to achieve Td,
Copy paper was obtained by smoothing with a super calendar.

Example 6 Both sides of the high-quality paper used in Example 1 were coated with a baking tray (Ansilex 93. Average particle size: 0.6 μm).

Manufactured by EMC > 60 parts, heavy calcium carbonate (NS-10
00, average particle size 1.17 μm, manufactured by Nitto Funka Co., Ltd.) 20 parts,
After drying a paint consisting of 15 parts of Soapless self-crosslinking acrylic emulsion (Duramar 5EK3O1, manufactured by Nippon Pure Chemical Industries, Ltd.) and 5 parts of polyvinyl alcohol (Poval 117, manufactured by Kuraray Co., Ltd.), the coating amount was F side / W side = 15 / 15g
/Td using an air knife coater, and smoothing was performed using a super calendar to obtain copy paper.

Example 7 Both sides of the high-quality paper used in Example 1 were coated with 85 parts of light calcium carbonate (Brilliant 1500, average particle size 0.15 μm, manufactured by Shiraishi Kogyo Co., Ltd.), styrene:butadiene:methacrylic acid = 60 parts:37 parts:3 After polymerizing 1 q of latex, 2 parts of diethylaminoethyl methacrylate were copolymerized to give 1 q.
After drying a paint consisting of 13 parts of amphoteric latex, 2 parts of oxidized starch (Ace A, manufactured by Tamago Cornstarch Co., Ltd.) and 2 parts of calcium stearate (Nobu Coat C-104, manufactured by San Nopco Co., Ltd.) as a lubricant, the amount of coating after drying was W side = 15/1! After coating with a blade coater to give M/m, smoothing treatment was performed with a super calendar to obtain copy paper.

Example 8 Both sides of the high-quality paper used in Example 1 were coated with heavy calcium carbonate (NS-2500, average particle size 0.89 μm, manufactured by Nitto Funka Co., Ltd. > 20 parts) and light calcium carbonate (Shiroenka PZ, average particle size 0.89 μm). After drying, the coating amount was as follows: F side/W side=12/12g/
After coating with a blade coater to achieve Td, smoothing treatment was performed with a cross calender to obtain copy paper.

Example 9 Light calcium carbonate (
Brilliant 1500. Average particle size 0.15 μm, Shiraishi Kogyo Co., Ltd.) 85 parts, SBR latex (JSRO662,
A coating consisting of 13 parts (manufactured by Japan Synthetic Rubber Co., Ltd.) and 2 parts of oxidized starch (Ace A, manufactured by Tamago Cornstarch Co., Ltd.) was coated with a blade coater so that the coating amount after drying was F side/W side = 12/12g/7Ff. After coating, smoothing treatment was performed using a super calendar to obtain copy paper.

Comparative Example 1 87 parts of kaolin clay (Ultra White 90, manufactured by EMC) and styrene were applied to both sides of the high-quality paper used in Example 1.
A paint consisting of 10 parts of butadiene latex (JSRO6/322 manufactured by Japan Synthetic Rubber Co., Ltd.) and 3 parts of oxidized starch (Ace A, manufactured by Tamago Cornstarch Co., Ltd.) was applied in an amount after drying of F side/W side = 15/159/ After coating with a blade coater so as to give a RD, smoothing treatment was performed with a super calender to obtain copy paper.

Comparative Example 2 Commercially available coated printing paper OK special art (manufactured by Tamako Paper Co., Ltd.) 84
．． 99 parts m.

Comparative Example 3 Commercially available coated printing paper New Gold e, <manufactured by Kanzaki Paper Co., Ltd.> 84
．． 9g/butt.

Comparative Example 4 Commercially available one-component magnetic toner development system Mita Kogyo Mita DC-
131 PPC paper for copying machines.

Comparative example 5 Commercially available Xerox L paper manufactured by Fuji Xerox.

Regarding the papers listed in Examples 1 to 9 and Comparative Examples 1 to 4, (1) basis weight, (2) thickness, (3) center line average roughness, (
4) Surface electrical resistance, (5) Air permeability, (6) Static friction coefficient,
(7) Highlight chroma, (8) Blank paper cross, (9) Solid image cross, (10) Image disturbance, (11) Blisters during fixing, and (12) Number of running troubles were measured and evaluated using the following methods. The results are shown in Table 1-1.1-2.
．． Shown in 2-1 and 2-2.

(1) Basis weight: Measured by the method of JISP8124.

(2) Thickness: Measured by the method of JISP8118.

(3) Center line average roughness: Pre-treated the test piece according to JIsP8111 (7) method, and
The surface was measured.

Measuring instrument used: Manufactured by Kosaka Laboratory Co., Ltd.

Universal surface shape measuring instrument 5urfcorder 5E-3C Cut-off (direct 0.8an, measurement length 8al11 (4) Surface electrical resistance: JISP8111 method and conditions are temperature 20±2℃,
The test piece was pretreated in accordance with JISP8111 at a humidity of 85 ± 2%, and each test piece was subjected to JISC21 under the same conditions as the pretreatment.
The surface resistivity was measured on one side by a method similar to that of No. 22.

Measuring instrument used: Manufactured by Kawaguchi Electric Manufacturing Co., Ltd.

Room temperature measurement box P-601 HIGHRESISTA NCE METER 329A manufactured by Yokogawa Hewlett-Packard Co., Ltd. Applied voltage: 100V (5) Air permeability: Measured by the method of JISP8117.

(6) Static friction coefficient: After smoothing the papers of Examples and Comparative Examples, they were cut into A4 size sheets of 500 sheets each using a guillotine cutting machine, and approximately 100 consecutive sheets in a stacked state, excluding the top few dozen sheets, were cut into A4 size sheets. was used as the test sample.

Regarding commercially available paper, the package was opened and about 100 consecutive sheets in the same stacked state as above were used as test samples.

J, TAPPI No. 30, fix the test sample on a horizontal plate of size 84, fix the top one of the test sample and the bottom of the weight with double-sided adhesive tape, and apply it sequentially up to the 10th plate. It was measured.

Measuring instrument used: Manufactured by Toyo Baldwin.

Tensilon UTM-III-100 (7) Highlight chroma: Magenta color toner with Fuji Xerox 3890 copier
An unfixed transfer image of a halftone gradation image of 5 to 85% of 175 lines was formed on one surface using the . Thereafter, the image was fixed using a double-sided heat fixing device consisting of a silicone rubber coated roll.

Spectral colorimetry is performed using the method of Jl5Z8722 for each halftone gradation, X, '1/, Y are calculated, and from the values JISZ8
The saturation C was determined by the method of 721. Further, the halftone dot area ratio of the same halftone dot was measured, and the relational expression between the saturation C and the halftone dot area ratio was determined by the least squares method. Using this relational expression, the saturation C when the dot area ratio is 0.4 was calculated and used as a highlight chroma.

Measuring instrument used: Manufactured by Hitachi, Ltd.

Spectrophotometer H330 manufactured by Toyo Ink Co., Ltd., BEUVAC (8) Blank paper gloss: Measured on the F side by a method according to JISP8142.

Measuring instrument used: Manufactured by GARDNER.

GARDNERGLO3 SGARDIII (9) Solid image gloss: A magenta solid image was obtained on the F side by the same method as the highlight chroma. The gloss of this solid image was measured in the same manner as the white paper cloth.

(10) Image disturbance: An unfixed transfer image of a magenta line image was formed by the same method as the highlight chroma.

A photomicrograph of this transferred image was taken with an optical microscope at a magnification of 50 times, and compared with a limit sample for evaluation.

The test paper is JISP8111 method and conditions: temperature 20℃±2℃, humidity 85±2%.
Pretreatment was performed in a manner similar to that described in .

The meanings of the symbols in the table are as follows.

0: Almost no image disturbance.

Δ: There is some image disturbance, but it is not noticeable visually.

X: Image disturbance is large and clearly visible even when visually observed.

(11) Blister m during fixing: A magenta halftone gradation image was formed using the same method as Highlight Chroma, with the temperature of the silicone rubber coated roll of the heat fixing device set at 180° C. and 200° C. This fixing device was visually evaluated for blisters.

The test paper was pretreated at a temperature of 20°C±2°C and a humidity of 85±2% in accordance with JISP8111.

The meanings of the symbols in the table are as follows.

○: No blisters observed.

62 Blisters are observed only in an area less than 1/10 of the area of the paper. .

X: Blisters are observed over 1/10 or more of the paper area.

(12) Number of running troubles: 5 sheets of accumulated paper collected using the same method as the static friction coefficient.
00 sheets each, set in the paper feed tray of a Fuji Xerox 5870 copier, and 1000 sheets of each sheet (Example 8,
9. For Comparative Examples 1 and 2.3, 100 copies were made, and the total number of troubles such as paper jams and double feeding was taken as the number of running troubles. Tables 1-1.1-2.2-1 and 2-2 From the results shown in , in order to bring the image distortion of paper conditioned under conditions of temperature 20'C and humidity 85% to a level that does not pose a practical problem, the surface electrical resistance of paper under the above conditions must be 8.0XIO.
It is clear that 8Ω or more, preferably 1.0×10 9 Ω or more is required.

In addition, in the evaluated fixing system and paper feeding system, blisters should not occur on more than 1/10 of the paper area;
It is desirable to have no more than 5 troubles per 1,000 sheets.

[Effects of the Invention] The present invention provides a transfer layer with a surface center line average roughness of 2.0 μm or less on at least one side of a base paper, and the surface electrical resistance of the transfer layer is 8.0XIO8Ω at a temperature of 20°C and a relative humidity of 85%. Provides electrophotographic transfer paper adjusted as described above,
It has the advantage of being able to produce high-quality copies with high cross-sections without image disturbance during transfer.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between the cross and center line average roughness of various types of paper.

Claims (1)

[Claims] A transfer layer with a surface centerline average roughness of 2.0 μm or less is provided on at least one side of the base paper, and the surface electrical resistance of the transfer layer is adjusted to 8.0 × 10^8 Ω or more at a temperature of 20 ° C. and a relative humidity of 85%. An electrophotographic transfer paper that is characterized by: