JP2002341582A - Electrophotographic transfer paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide electrophotographic transfer paper with which images having high glosiness can be formed and the occurrence of a blister can be suppressed without the occurrence of wrapping in fixing. SOLUTION: The Bekk smoothness (JISP-8119-1998) of base paper 1 of the electrophotographic transfer paper which is a basis weight of 60 to 130 g/m<2> , is provided with a coating layer 2 on at least one surface thereof and has the glosiness of the surface of >=15% (measured at 60 deg.) is set at >=100 seconds.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic transfer paper used for an electrophotographic apparatus or an electrostatic recording apparatus.

[0002]

2. Description of the Related Art Conventionally, digitization of an electrophotographic color recording apparatus has been advanced, and high image quality has been achieved. As a result, in the field of on-demand publications,
In order to publish smaller copies more easily, color copiers and color printers are increasingly used.

[0003] Printed materials are also being manufactured by copying machines and printers. Generally, coated paper used for printing is generally called art paper or coated paper, and a paper having a relatively high glossiness tends to be called art paper.
With respect to this art paper, usually, a pigment having an average particle diameter of 2 μm or less is applied with a coater of at least 10 g / m ² per one side of the base paper, and then the surface is smoothed by calendering to produce a product. In this art paper, a more vivid image can be formed than before in a color copying machine or a color printer. Therefore, in recent years, PPC paper and print paper have been increasing.

[0004]

However, when such a coated paper is simply produced, when smoothness is obtained at the above-mentioned basis weight, when coating with ordinary paper is performed, processing such as calendering is performed. The paper is crushed by this,
There is a problem that the stiffness of the paper is weakened and the paper is wound around the fixing roller.

[0005] Further, in the case where the smoothness of the surface is to be obtained without crushing the paper, the amount of coating increases, and a blister peculiar to the printing paper (this is because the air permeability of the coating paper for printing is small because This is due to the fact that the paper layer is peeled off when the water vapor in the paper is heated and expanded, especially in a high-humidity environment).

Further, when the amount of coating is small, the smoothness of the surface is not sufficiently obtained, and when an image is formed by an electrophotographic apparatus, a colorful image cannot be formed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and its object is to form an image having a high glossiness, to prevent occurrence of fixing wrap, and to suppress the occurrence of blisters. An object of the present invention is to provide an electrophotographic transfer paper.

[0008]

In order to achieve the above object, the present invention provides a coating layer having a basis weight of 60 to 130 g / m ² on at least one surface and a glossiness of the surface of 15% or more (60% or more).
Beck smoothness (J) of the base paper of electrophotographic transfer paper
ISP-8119-1998) for at least 100 seconds.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view of a transfer paper used in the present invention. In FIG. 1, reference numeral 1 denotes a base paper, 2 denotes a coating layer, and 3 denotes a back coating layer. Smoothness is 10
Must be at least 0 seconds. If the smoothness is less than 100 seconds, the resin to be applied permeates, and when forming an image, colorful gloss is lost. Other than that, it may be made of a general material such as acidic or neutral high-quality paper, neutral paper, waste paper, and recycled paper. Further, as for the paper for which the smoothness has not been obtained for 100 seconds or more, the smoothness may be obtained by slightly coating the surface layer as shown in FIG. 2 (in FIG. 2, reference numeral 4 denotes a filling layer). . In this case, the coating amount must be ^{0.5g / m 2 ~4g / m 2} . If the coating amount is less than 0.5 g / m ² , the surface of the paper will have irregularities, and it will be meaningless to apply the actual coating thereon. The coating amount is 4 g / m ²
When it exceeds, blisters are easily generated.

Further, the material to be applied must be different from the material to be actually coated. For example, when an acrylic resin for a paint is used for the coating layer, a water-soluble emulsion is used as a filler resin for the base paper.

As the resin, a general resin for coating may be used. For example, a water-soluble adhesive having high adhesive strength, an emulsion, a latex, or the like can be used alone. For example, polyvinyl alcohol, modified polyvinyl alcohol, starch, gelatin, casein, methylcellulose, hydroxyethylcellulose, acrylamide-
Acrylic ester copolymer, acrylamide-acrylic resin-methacrylic acid terpolymer, styrene-acrylic resin, isobutylene-maleic anhydride resin, water-soluble resin such as carboxymethylcellulose, acrylic emulsion, vinyl acetate emulsion , Vinylidene chloride emulsion, polyester emulsion, vinylidene chloride emulsion, polyester emulsion, styrene-butadiene latex, acrylonitrile-butadiene latex, acrylonitrile-butadiene latex, and the like.

Further, regarding the coating layer to be actually coated,
Common pigments such as heavy calcium carbonate, light calcium carbonate, titanium dioxide, aluminum hydroxide, satin white, talc, calcium sulfate, barium sulfate, zinc oxide, magnesium oxide, magnesium carbonate, amorphous silica, colloidal silica, Mineral pigments such as white carbon, kaolin, calcined kaolin, delaminated kaolin, aluminosilicate, sericite, bentonite, polystyrene resin fine particles, urea formaldehyde resin fine particles, fine hollow particles, and other organic pigments alone or in combination. Is also good.

As the adhesive in the coating layer, a water-soluble adhesive or emulsion, latex, or the like, which is a general adhesive for coating and has a strong adhesion to additives such as a substrate and a pigment, is used alone. be able to. For example, polyvinyl alcohol, modified polyvinyl alcohol, starch, gelatin, casein, methylcellulose, hydroxyethylcellulose, acrylamide-acrylate copolymer, acrylamide-acrylic resin-methacrylic acid terpolymer, styrene -Acrylic resin, isobutylene-maleic anhydride resin, water-soluble resin such as carboxymethyl cellulose, acrylic emulsion, vinyl acetate emulsion, vinylidene chloride emulsion, polyester emulsion, vinylidene chloride emulsion, polyester emulsion, styrene-butadiene latex, acrylonitrile Using butadiene latex, acrylonitrile-butadiene latex or the like;

Further, the point which is effective in the present coating method is also effective in that general materials used for paint can be used. For example, specifically, a liquid paint containing a resin composition, a white pigment, and an organic solvent as main components is exemplified. In the colored base paint, a colored pigment may be used, and the above pigment is mainly used for a white pigment. As the resin composition, a normal thermosetting resin composition is preferable, for example,
Hydroxyl group, carboxyl group, silicon-containing group, epoxy group,
One or two or more selected from acrylic resins, vinyl resins, polyester resins, alkyd resins, urethane resins, etc. having one or more functional groups selected from isocyanate groups which may be blocked, etc. Base resin, selected from melamine resin, urea resin, polyisocyanate compound which may be blocked, carboxyl group-containing compound, epoxy group-containing compound, etc., which react with these functional groups to improve paper strength of paper Mixtures of one or more crosslinking agents are included.

Examples of the organic solvent for coating this include hydrocarbons such as hexane, heptane, xylene, toluene and cyclohexane; methyl acetate, ethyl acetate, ethylene glycol monomethyl ether,
Ester systems such as diethylene glycol monomethyl ether acetate; ether systems such as isopropyl ether, ethylene glycol monomethyl ether and diethylene glycol monobutyl ether; alcohol systems such as ethyl alcohol, butyl alcohol and hexyl alcohol; methyl isobutyl ketone, methyl ethyl ketone, isophorone;
Ketones such as acetophenone; and the like.

[0017] Regarding the coating method, it is usually necessary not to perform size press when the coating is performed by gate roll coating which is an on-machine coater. That is, it is necessary to smooth the surface without crushing.

In the off-machine coater, blade coating, air knife coating, roll coating, curtain coating, gravure coating, etc. are used without applying too much pressure. It is preferable that pressure is not applied as much as possible.

The coating amount is 1 g / m ² at 1 to ²⁰ g / m ^2.
If it is less than m ² , it is difficult to achieve a surface gloss of 15% or more. On the other hand, if it is larger than 20 g / m ² , the overall grammage increases and the stiffness becomes strong, which causes a problem in the transportability in the electrophotographic apparatus and causes problems such as blisters.

The coating pressure is 50 kg / cm ²
Is exceeded, the paper is crushed and the paper strength of the transfer paper is 1
It is less than 6cm. In the case of such strength, a phenomenon in which the paper is wound around the fixing roll when passing through the heat roll occurs.

Here, the measurement of the glossiness of the surface of the transfer paper according to the present invention will be described. As for the gloss, it is common to use 75 degree specular gloss of JISP-8142-1993. In this case, a measuring device with an angle is used in order to obtain a more detailed correlation with the appearance. It was to be. 6 based on P-8142-1993
It was decided to use one using specular gloss of 0 degrees. The condition of the transfer paper was 15% or more as measured by the apparatus. FIG. 4 is a sectional view of a specific measuring device.

Next, a multi-transfer type electrophotographic apparatus using transfer paper according to the present invention has been put to practical use. One example is shown in FIG.

The image forming apparatus shown in FIG.
11, a yellow developing unit 212, a magenta developing unit 213, and a cyan developing unit 214 which are attached and detached in the order of image formation around
And a black developing unit 215, a rotatable transfer drum 207 for wrapping a transfer paper such as a film around the photosensitive drum 211 and sequentially transferring a toner image from the photosensitive drum 211, a charger 219 required for forming a latent image, and image exposure. System E, etc.

In this apparatus, when a full-color image is formed, the transfer paper P pulled out from the paper feed tray 202 or the like is taken out by the paper feed roller 205 in the direction of the arrow shown in the figure, and is carried by the conveyance rollers 220, 221, 222, and 223. The toner is conveyed to the transfer drum 207, and is wound around the transfer drum 207 by electrostatic attraction using a suction brush 208. Then, the toner images of many colors are sequentially transferred to the transfer paper P on the transfer drum 207 from the photosensitive drum 211 in accordance with the image forming procedure. The transfer at this time is performed by the transfer brush 216.

That is, PVDF (polyvinylidene fluoride)
A charge having a polarity opposite to the charging characteristic of the toner is applied to the back surface of the transfer drum 207 from the inside of the transfer drum 207 made of a dielectric sheet such as the toner, and an electric field generated by the applied charge causes the transfer brush 216 to have a charge on the dielectric sheet. The transfer is performed by attracting the toner to the surface of the transfer paper P.

Next, this transfer is repeated many times for each color toner of magenta (M), cyan (C), yellow (Y), and black (K), so that M,
C, Y, and K color images are formed, and the transfer paper P is passed through a heat fixing device 218 to melt and mix the color toners to obtain a full-color image.

The transfer material transport system includes transfer material feed trays 201, 202, and 203 provided below the apparatus main body 200.
And paper feed rollers 204, 205, 206 disposed almost directly above these paper feed trays 201, 202, 203.
And the paper feed rollers 204, 205, and 206, and are disposed near the paper feed rollers 204, 205, and 206.
223, a transfer roller 224, a separation charger 217, and a static eliminator 225 are arranged near the outer peripheral surface from the upstream in the rotation direction, and the suction brush 208, the transfer brush 216, and the static eliminator brush 226 are arranged on the inner peripheral side. The transfer drum 207 provided rotatably in the direction of the arrow, the separation claw 227 near the transfer drum 207, and the separation claw 22
7, a conveyor belt means 228 provided in the vicinity of
The conveying belt means 228 is disposed in the vicinity of the terminal end in the conveying direction, extends outside the apparatus main body 200, and extends outside the apparatus main body 200.
A heat fixing device 218 is provided in proximity to a discharge tray 229 which is detachable from the fixing tray 00.

The heat fixing device 218 includes a fixing roller 230 having a heater therein, a pressure roller 231 facing the fixing roller 230, and a release agent application device for applying a release agent such as silicon oil to the fixing roller 230. 232 and a cleaning roller 233 to the fixing roller 230.

In the case of double-sided printing, the transfer paper P is transported in the direction of arrow D in FIG. Then, the paper is fed by a paper feed roller 263 similar to the paper feed rollers 204 to 206, and an image is formed in the same manner as in the image forming method.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. Note that the present invention is not limited to the embodiments.

[Example 1] B. K. P (hardwood pulp) 6% by weight titanium oxide, 6% by weight on a dry weight basis
Of kaolin, 0.5% by weight of a sulfuric acid band, 0.3% of a rosin sizing agent, and 3.2% by weight of a pulp suspension prepared by mixing a water-soluble binder with a fourdrinier paper machine. The paper was made, dried and adjusted to have a water content of 5% after paper making, and the smoothness was adjusted to 130 seconds by calendering. The fine paper was mixed with 150 parts of acrylic resin for coating by silk screen coating, mixed with 2 parts of white pigment, diluted with toluene and coated, and the coated amount after drying was 7 g.
/ M ² . The glossiness of the surface of the transfer paper was 19% (Gloss Checker IG-320 manufactured by Horiba, Ltd.).
The paper strain (in the CD direction) was set to 20 cm.

The resulting paper was passed through a full-color copying machine CLC-800 manufactured by Canon Inc. to form a full-color image, and the gloss of the FF image and the wraparound of the fixation were evaluated when the image was formed. Table 1 shows the results.

Table 1 In Example 1, as shown in Table 1, an image having high image gloss was obtained, and no wrapping around the fixing device occurred.

Example 2 A high-quality paper having a smoothness of 50 seconds was used in Example 1, and 4% by weight was used as a sealing layer.
A mixture of 12% by weight of kaolin and 0.5% of a neutral rosin sizing agent is applied to a water-soluble binder, and the mixture is coated so that the coating amount after drying is 3 g / m ^2. Transfer papers having the various physical properties shown in Table 1 were produced in the same manner as in Example 1 except that the base paper adjusted to a degree of 500 seconds was used (the paper strainer was 21 cm in the CD direction).

When the obtained transfer paper was evaluated in the same manner as in Example 1, it was confirmed that an image having high gloss was obtained as in Example 1. Also, there was no winding around the fixing roller. Table 1 shows the results.

Example 3 Example 3 was repeated except that the concentration of the pulp suspension wave was reduced to a basis weight of 64 g / m ² and a paper strain (in the CD direction) was 17.2 cm. Transfer paper having the physical properties shown in Table 1 was produced in the same manner as in Example 2.

When the obtained transfer paper was evaluated in the same manner as in Example 1, it was confirmed that an image having a high gloss similar to that of Example 1 could be obtained.

<Comparative Example 1> In Example 1, the coating was performed in the same manner as in Example 1 except that the base paper used had a smoothness of 20 seconds, but the glossiness of the transfer paper was about 8, and An image evaluation similar to that of No. 1 was performed, but a bright image with high gloss was not obtained.

<Comparative Example 2> In Example 1, the surface gloss was increased as shown in Table 1 by performing a super calendar treatment after the size press. At that time, the glossiness was 25%. However, the paper strain is 1 in the CD direction.
5 cm, and wrapping occurred with the fixing roller.

<Comparative Example 3>
The amount of coating after drying the base paper was 15 g / m ^Two When
Paper in the same manner as in Example 1 except that
Was evaluated and blistered in a high humidity environment.
There has occurred.

[0041]

As is apparent from the above description, according to the present invention, a coating layer having a basis weight of 60 to 130 g / m ² is provided on at least one side, and the glossiness of the surface is 15% or more (measured at 60 degrees). ) Beck smoothness of base paper of electrophotographic transfer paper (JIS)
(P-8119-1998) is set to 100 seconds or more, so that it is possible to obtain an electrophotographic transfer paper which can form an image having a high gloss level, does not cause fixing wrapping, and can suppress the generation of blisters. it can.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing the structure of a full-color electrophotographic transfer paper according to the present invention.

FIG. 2 is a sectional view schematically showing a structure in which a filling layer is also provided on the full-color electrophotographic transfer paper according to the present invention.

FIG. 3 is a cross-sectional view illustrating a configuration of the electrophotographic apparatus.

FIG. 4 is a cross-sectional view of a glossiness measuring device.

[Explanation of symbols]

 1 base paper 2 coating layer 3 back coating layer 4 sealing layer

Claims (7)

[Claims] 1. A coating layer having a basis weight of 60 to 130 g / m ² is provided on at least one side, and the glossiness of the surface is 15% or more (60% or more).
), Wherein the base paper has a Bekk smoothness (JISP-8119-1998) set to 100 seconds or more. 2. The electrophotographic transfer paper according to claim 1, wherein a smoothing process is not performed during the processing. 3. The transfer paper for electrophotography according to claim 1, wherein the resin of the coating layer is a resin for paint. 4. The transfer paper for electrophotography according to claim 1, wherein the resin of the coating layer mainly comprises a pigment and an adhesive. 5. The coating amount of at least one side of the base paper is 1
2. The transfer paper for electrophotography according to 1, wherein the transfer paper weight is from 20 to ²⁰ g / m ² . 6. The transfer paper for electrophotography according to claim 1, wherein the coating device is constituted by a device such as silk-screen printing which does not exert excessive pressure. 7. The transfer paper for electrophotography according to claim 1, wherein the nip pressure is 50 kg / cm ² or less.