JPH11160905A - Electrophotographic transfer sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electrophotographic transfer sheet capable of forming a high-grade image free from unevenness in the gloss of the image part. SOLUTION: A thermoplastic resin-base transparent resin layer is disposed on at least one face of a substrate. The thermoplastic resin has a number average mol.wt. (Mn) of 5,000-20,000 and 30-80 deg.C glass transition temp. The surface of the substrate has >=50% 75 deg. blank paper glossiness stipulated by JIS Z8741 and <=10 μm max. height (Rmax) stipulated by JIS K0601. The surface of the transparent resin layer has >=90% 75 deg. blank paper glossiness stipulated by JIS Z8741 and <=5 μm max. height (Rmax) stipulated by JIS K0601.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic method applied to a color copying machine or a color printer.
The present invention relates to a color image transfer member capable of forming a high-quality full-color image, and more particularly to a transfer sheet for electrophotography in which a printed portion and a blank portion have high gloss and can form a clear color image. .

[0002]

2. Description of the Related Art As a method of forming a color image by an electrophotographic method, an electrostatic latent image is formed for each color by irradiating color separation light on a photosensitive material, and the electrostatic latent image for each color is formed. Y
(Yellow), M (magenta), C (cyan), etc., are sequentially developed to form a color toner image for each color, and the toner image of each color is superimposed on the transfer body every time the toner image is formed. There is a method of forming a color image by transferring the toner images together, heating and fixing these toner images.
As another method, a color toner image for each color is superimposed on a photosensitive material instead of a transfer body to form a color toner image, and the superimposed color toner images are collectively transferred onto a transfer body and heated. And fixing to form a color image.

[0003] Color toners are usually constituted by dissolving or dispersing various dyes or pigments as colorants in a binder resin.
It is several μm to several tens μm. As a receptor for such a color toner, a paper substrate such as plain paper or coated paper such as general printing paper is used, and a plurality of layers of color toner are superimposed on the paper substrate and heated and fixed. Thus, a color image is formed. Since the surface of the color image formed in this manner has irregularities of, for example, about 10 to 100 μm (JP-A-63-92965), the unevenness of the toner layer causes uneven gloss of the image. Will occur. That is, since the illumination light incident on the formed color image is irregularly reflected on the surface of the color image having severe unevenness, the gloss of the image becomes insufficient when observed with the naked eye.

In order to solve the above problems, a method has been disclosed in which a transparent resin layer having a coating thickness of 50 to 100 μm is provided on a substrate, and a toner image is embedded in the transparent resin layer by a hot roll fixing device. I have. JP-A-5-127413 discloses that a toner image is placed on the surface of an image transfer sheet having a transparent resin layer made of a cross-linked resin soluble in tetrahydrofuran, having a glass transition temperature of 40 to 70 ° C., and a belt-like fixing method. A method of embedding toner in a transparent resin layer with a container is disclosed. Further, JP-A-5-216322 and JP-A-6-11982 disclose that a toner image is placed on the surface of an image transfer sheet coated with a thermoplastic resin, and the toner is applied to the transparent resin layer by a belt-shaped fixing device. A method of embedding in the document is disclosed. In the technology of each of the above publications, when a color toner image is fixed on a transfer body, the color toner image is heated and melted by pressing the color toner image with a hot roll, so that the color toner image is transferred into the transparent resin layer on the surface of the electrophotographic transfer sheet. The image is fixed so as to be embedded so as to form a color image with less unevenness on the surface, reduce irregular reflection of light, and obtain a high-quality image with high gloss matching and no gloss unevenness.

However, according to the techniques disclosed in the above publications, the transparent resin layer provided on the transfer sheet for electrophotography is not sufficient to embed the color toner particles transferred on the transfer sheet, and a high gloss without unevenness in gloss is obtained. A high-quality image cannot be formed sufficiently.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and it is possible to produce a high-quality image without gloss unevenness in an image portion, as compared with the prior art. An object of the present invention is to provide an electrophotographic transfer sheet that can be formed.

[0007]

The transfer sheet for electrophotography according to the present invention has a base material, and a transparent resin layer formed on at least one surface of the transfer sheet and containing a thermoplastic resin as a main component. The thermoplastic resin contained in the transparent resin layer has a number average molecular weight (Mn) of 5,000 to 20.
000 and its glass transition temperature is 30-85 ° C
A 75 ° white paper glossiness based on JIS Z8741 of 50% or more based on JIS Z8741 and the JI
The maximum height Rmax based on SK0601 is 10 μm or less, and further, JIS Z on the surface of the transparent resin layer
The glossiness at 75 degrees based on 8741 is 90% or more, and the maximum height Rm based on JIS K0601
ax is 5 μm or less. Further, it is preferable that the thermoplastic resin used for the transfer sheet for electrophotography according to the present invention is selected from polyester resins. Further, the thickness of the coating film of the transparent resin layer of the electrophotographic transfer sheet according to the present invention is preferably 3 to 20 μm.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The inventors of the present invention have proposed a transfer sheet for electrophotography in which the gloss unevenness of an image has been eliminated, in particular, the properties of a substrate, the resin physical properties of a transparent resin layer provided thereon, and the sheet after coating. The characteristics were studied diligently. As a result, the inventors have found out the requirements necessary for obtaining a high-quality image without gloss unevenness of the image, and have completed the present invention based on the requirements. Hereinafter, the present invention will be described specifically.

The fixing of the color toner on the transfer sheet for electrophotography is achieved by heating and melting the toner adhered on the transfer sheet by a hot roll fixing device. If the toner is not embedded, the gloss changes according to the change in the thickness of the toner, and the quality of the image is significantly reduced. Therefore, it is important to embed the toner in the transparent resin layer in order to eliminate uneven gloss. That is, in order to embed the toner, it is necessary that the toner is sufficiently melted by heating for a short time, and at the same time, the transparent resin is also softened so that the toner can be embedded and is compatible with the toner. As a result of intensive studies on this requirement, the transparent resin layer was formed with a polyester resin as a main component, and the number average molecular weight (M
The above requirements were successfully achieved by controlling n) within the range of 5000 to 20,000 and controlling the glass transition temperature within the range of 30 to 85 ° C. When the molecular weight (Mn) is more than 20,000, the softening of the transparent resin layer during fixing heating is insufficient, so that it is difficult to embed the toner and the gloss matching property is reduced. When the molecular weight (Mn) is less than 5,000, the coating film is insufficiently formed, so that the coating film is cracked. When the glass transition temperature is less than 30 ° C.,
When the blocking property of the obtained transfer sheet is increased and a problem occurs in the running property, and when it exceeds 85 ° C., the softening of the transparent resin layer is insufficient under the fixing heating condition, and the embedding of the toner is insufficient. Become.

As a resin constituting the transparent resin layer, a polyester resin, a styrene-acrylate resin, a styrene-methacrylate resin and the like can be used, and it is particularly preferable to use a polyester resin. Examples of the polyhydric alcohol component and the polyhydric carboxylic acid component constituting the polyester resin include the following.

The polyhydric alcohol component includes ethylene glycol, propylene glycol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, Neopentyl glycol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, a monomer obtained by adding an olefin oxide to bisphenol A, or the like can be used.

The polycarboxylic acid component includes maleic acid, maleic anhydride, fumaric acid, phthalic acid, terephthalic acid, isophthalic acid, malonic acid, succinic acid, glutaric acid,
Dodecyl succinic acid, n-octyl succinic acid, n-dodecyl succinic acid, 1,2,4-benzenetricarboxylic acid,
1,2,4-cyclohexanetricarboxylic acid, 1,2,2
4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxy-2-methyl-
2-Methylenecarboxypropane, tetra (methylenecarboxy) methane, 1,2,7,8-octanetetracarboxylic acid, trimellitic acid, pyromellitic acid and lower alkyl esters of these acids can be used.

The polyester resin used in the present invention comprises:
It is synthesized by polymerization of one or more polyhydric alcohol components and one or more polyhydric carboxylic acid components. As a resin component of the toner, a polyester resin is generally used for a color toner, and a styrene-
Since an acrylic resin is mainly used, it is preferable to select a thermoplastic resin having high compatibility with the toner as the thermoplastic resin forming the transparent resin layer. Accordingly, one or a mixture of two or more of polyester resins, styrene-acrylate resins, styrene-methacrylate resins, and the like are used depending on the purpose.

Further, the transparent resin layer may contain a pigment, a release agent, a conductive agent, and the like as long as the transparency is not impaired. In that case, the amount of the main component resin is preferably 80% by weight or more based on the total weight of the resin layer. Further, it is preferable that the composition of the transparent resin layer is adjusted so that the surface electric resistance becomes 8.0 × 10 ⁸ Ω or more at a temperature of 20 ° C. and a relative humidity of 85%.

Further, the present inventors have determined that the glossiness and surface roughness of the base material on which the above-mentioned transparent resin layer is to be applied and the transfer sheet for electrophotography provided with the above-mentioned transparent resin layer are such that the blank portion of the image portion and the toner It was found that it had a significant effect on the gloss of the part, and intensive studies were made. As a result, the JIS
The glossiness of blank paper at an incident / receiving angle of 75 degrees based on Z8741 is controlled to 50% or more, and its JIS K0
The maximum height Rmax based on 601 is controlled to 10 μm or less, and the JIS Z8 of the surface of the transparent resin layer is further controlled.
The glossiness of the blank paper at an incident / receiving angle of 75 degrees based on
% And its JIS K0601
By controlling the maximum height Rmax to 5 μm or less based on the above, the gloss of the image area was successfully made uniform, and the present invention was completed.

As a base material on which the transparent resin layer is to be applied, high-quality paper has been mainly used in the past, so that its white paper glossiness is about 5% and its maximum height Rmax is also 15 to 30.
It was about μm. For this reason, the thickness of the coating film of the transparent resin layer to be applied is 30 in order to eliminate irregularities on the coating film surface.
It was required to be not less than μm. The image formed on such an electrophotographic transfer sheet is irregularly reflected at the white paper portion (transparent resin layer) and the toner portion due to surface irregularities. In addition, the incident light transmitted through the white paper portion and the toner portion is irregularly reflected by irregularities of the base material, and thus has extremely low gloss. Further, since the thickness of the coating film of the transparent resin layer is increased, it is difficult to sufficiently soften the transparent resin layer by the heat of the fixing roll, so that the embedding of the toner is insufficient.

The substrate used in the present invention has an incident / reception angle of 7 based on JIS Z8741 on its surface.
5 degree white paper glossiness is 50% or more and its JIS
The maximum height Rmax based on K0601 is 10 μm or less. Further, since the above-mentioned transparent resin layer is coated on the surface of the base material, the thickness of the coating film is sufficient to be 3 to 20 μm. Further, the surface of the transparent resin layer formed thereon has a white paper glossiness of 90% or more at an incident / reception angle of 75 degrees according to JIS Z8741 and JIS K0601.
Has a high smoothness of not more than 5 μm based on the maximum height Rmax, so that the incident light on the white paper portion and the toner portion is transmitted with almost no surface reflection, and the transmitted light is also a highly smooth base. Reflected efficiently on the material. Further, since the thickness of the coating film is 20 μm or less, the transparent resin layer is sufficiently softened by the heating roll at the time of transfer, so that the toner is sufficiently embedded, and uniform and high gloss of the image area can be obtained. . Furthermore, JIS Z87 on the surface of the substrate
Glossiness of blank paper at 75 degrees incident / receiving angle based on 41 is 60%
The maximum height Rmax based on JIS K0601 is preferably 8 μm or less. Also, regarding the surface of the electrophotographic transfer sheet provided with the transparent resin layer, the glossiness of the white paper at an incident / receiving angle of 75 degrees according to JIS Z8741 is 95% or more, and JI
The maximum height Rmax based on SK0601 is preferably 4 μm or less. Further, the thickness of the coating film of the transparent resin layer is preferably 15 μm or less so that the transparent resin layer is easily softened.

The base material used in the present invention forms a pigment coating layer on at least one surface of general high-quality paper by applying a coating liquid mainly composed of a pigment and an aqueous binder, and smoothes the layer. It is obtained by performing processing. As pigments, for example, heavy calcium carbonate, light calcium carbonate, kaolin, calcined kaolin, structural kaolin, delamikaolin,
Talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, alumina, magnesium carbonate, magnesium oxide, silica, magnesium aluminosilicate, particulate calcium silicate, particulate magnesium carbonate, particulate light calcium carbonate, white carbon, bentonite, zeolite , Sericite, mineral pigments such as smectite, polystyrene resin, styrene-acrylic copolymer resin, urea resin, melamine resin, acrylic resin, vinylidene chloride resin, benzoguanamine resin and their fine hollow particles and through-hole type organic pigments And the like, and one or more of these are used.

As the adhesive for the pigment coating layer, a water-soluble and / or water-dispersible polymer compound is used.
Cationic starch, amphoteric starch, oxidized starch, enzyme-modified starch,
Starches such as thermochemically modified starch, esterified starch, etherified starch, cellulose derivatives such as carboxymethylcellulose and hydroxyethylcellulose, natural or semi-synthetic polymer compounds such as gelatin, casein, soy protein, natural rubber, and polyvinyl alcohol , Polydienes such as isoprene, neoprene, polybutadiene, polyalkenes such as polybutene, polyisobutylene, polypropylene, polyethylene, vinyl halide, vinyl acetate, styrene, (meth) acrylic acid, (meth) acrylic acid ester, (meth) acrylamide, Vinyl polymers and copolymers such as methyl vinyl ether, synthetic rubber latex such as styrene-butadiene and methyl methacrylate-butadiene, polyurethane resin, polyester resin, polyamide resin, olefin Down - maleic acid resins, and synthetic polymer compounds such as melamine resin. One or two or more of these are appropriately selected and used according to the quality target of the electrophotographic transfer sheet.

The compounding ratio of the adhesive is preferably in the range of 5 to 50 parts by weight with respect to 100 parts by weight of the pigment.
If the amount is less than 5 parts by weight, the surface of the substrate is damaged by the resin liquid when the transparent resin layer is coated on the obtained coating layer, so that it is not possible to obtain a good degree of white paper gloss. On the other hand, if it exceeds 50 parts by weight, bubbles are generated at the time of coating the pigment coating layer, and roughness is generated on the coated surface, so that good white paper gloss cannot be obtained.

In the coating liquid for the pigment coating layer, in addition to these, various auxiliaries such as a surfactant, a pH adjuster, a viscosity adjuster, a softener, a gloss imparting agent, a wax, a dispersant, Flow modifiers, antistatic agents, stabilizers, antistatic agents, crosslinking agents,
A sizing agent, a fluorescent whitening agent, a coloring agent, an ultraviolet absorber, an antifoaming agent, a waterproofing agent, a plasticizer, a lubricant, a preservative, a fragrance, and the like can be appropriately used as needed.

The coating amount of the pigment coating layer is appropriately selected according to the purpose of use of the receiving paper of the present invention, but is generally sufficient to completely cover irregularities on the substrate surface. Is required, and the dry weight is preferably 8 to 40 g / m ² . As a coating method for forming a coating layer, generally known coating equipment, for example, a blade coater, an air knife coater, a roll coater, a reverse roll coater, a bar coater, a curtain coater, a die coater, a gravure coater,
Champplex coater, brush coater, two-roll or metering blade type size press coater,
A bill blade coater, a short dwell coater, a gate roll coater, or the like is appropriately used.

The pigment coating layer is formed on one side or both sides of the base material, and the coating layer may have a multilayer structure by providing one layer or, if necessary, two or more intermediate layers. In the case of a double-sided coating or a multilayer structure, each coating liquid does not need to have the same or the same coating amount, and may be appropriately adjusted and blended according to a required quality level. When a coating layer is provided on one side of the substrate, a coating layer made of a synthetic resin layer or a pigment and an adhesive or an antistatic layer is provided on the back side to prevent curling, provide printability, and supply / discharge. It is also possible to impart paper suitability and the like. In addition, various processing on the back of the base material,
For example, by applying post-processing such as adhesion, magnetism, flame retardancy, heat resistance, water resistance, oil resistance, and anti-slip, it is of course possible to add suitability for various uses.

The substrate having the pigment coating layer of the present invention is subjected to a smoothing treatment in a usual drying step, surface treatment step, or the like.
The water content is adjusted so as to be 3 to 10% by weight, more preferably about 4 to 8% by weight. When performing the smoothing process, the incident light based on JISZ8741 is used.
The glossiness of blank paper at a light receiving angle of 75 degrees is 50% or more, and J
Maximum height Rmax based on IS K0601 is 10 μm
It is adjusted to be as follows.

When the substrate is subjected to a smoothing treatment, it is carried out using a smoothing treatment device such as a normal super calender, gross calender or soft calender. Also, it may be applied as appropriate on or off-machine, the form of the pressurizing device,
The number of pressure nips, heating, and the like are also appropriately adjusted according to a normal smoothing treatment device.

The substrate of the present invention is not particularly limited. For example, acidic papermaking having a papermaking pH of about 4.5, or an alkaline filler such as calcium carbonate as a main component, and a papermaking pH of about 6 to a weakly acidic to about A paper base such as neutral papermaking having weak alkalinity of 9 is used. As for the paper making method, a general paper machine such as a long net multi-tube type, a round net single-tube type, a Yankee or the like is appropriately used. Also, synthetic paper, nonwoven fabric, and synthetic resin film can be used according to the application.

For coating the transparent resin layer on the substrate, generally known coating apparatuses, for example, apparatuses such as a reverse roll coater, a bar coater, a curtain coater, a die coater, and a gravure coater are appropriately used.

The sheet coated with the transparent resin layer may be subjected to a smoothing treatment, if necessary. This smoothing treatment is carried out by a smoothing treatment device such as a normal super calender, gross calender or soft calender. Will be applied. Further, the form of the pressurizing device, the number of pressurizing nips, heating and the like are appropriately adjusted in accordance with a normal smoothing device.

[0029]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which, of course, are not intended to limit the scope of the present invention. "Parts" and "%" in the examples
Represents "parts by weight" and "% by weight" unless otherwise specified.

[0030] In each of Examples 1-2 Examples 1 and 2 were produced electrophotographic transfer sheet by the following process. [Preparation of Support] LBKP (Freeness (CSF) = 4
80 parts) To 100 parts of the pulp slurry, 10 parts of talc, 1.5 parts of a rosin emulsion sizing agent and 2 parts of a sulfuric acid band were added as fillers, and the mixture was diluted with white water to have a pH of 5.3 and a solid concentration of 1. A 1% stock slurry was prepared. The stock slurry was paper-made using a fourdrinier paper machine, and the obtained wet paper was coated with a size press solution having a solution concentration of 6% of oxidized starch (trade name: Ace A, manufactured by Oji Cornstarch Co., Ltd.) at an application amount of The coated paper was applied with a size press so as to have a dry weight of 2.0 g / m 2 and dried, and the obtained paper was subjected to a smoothing treatment using a machine calendar so that the Beck smoothness was 40 seconds, and the basis weight was 80 g. / M ² was obtained.

[Preparation of Coating Liquid] Kaolin (average particle size:
0.3 μm trade name; UW-90 Engelhard Co.)
50 parts by weight (solid content; the same applies hereinafter), 30 parts by weight of light calcium carbonate (average particle diameter: 0.6 μm, trade name; Brilliant S15, manufactured by Shiraishi Calcium Co.), heavy calcium carbonate (average particle diameter: 0.5 μm, trade name: Hydrocurve Sodium polyacrylate (trade name: Alon A-9, manufactured by Toagosei Co., Ltd.) as a dispersant was added to 20 parts by weight of K9 (Bihoku Powder Chemical).
2 parts (solid ratio to pigment; the same applies hereinafter) were added, and these were dispersed in water using a CORES disperser to prepare a pigment slurry. 3.0 parts by weight of oxidized starch (trade name; Ace A, manufactured by Oji Cornstarch Co., Ltd.) and styrene-butadiene copolymer latex (trade name: T25) were added to this pigment slurry.
13K of 50K (manufactured by Nippon Synthetic Rubber Co., Ltd.) was added and stirred, and water was further added to prepare a coating solution having a solid content of 53%.

[Formation of Coating Layer on Support] The obtained coating solution was applied to one surface of the support by a dry weight of 25 g / m ^2.
It is coated on both sides using a blade coater and passed through a pressure nip composed of a metal roll and an elastic roll to obtain a white paper glossiness with an incident / reception angle of 75 degrees according to JIS Z8741 and JIS K0601. The maximum roughness Rmax was adjusted to 55%, 8.0 μm (Example 1), and 65%, 3.0 μm (Example 2), respectively, to produce a substrate having a basis weight of 130 g / m ² . .

[Formation of Transparent Resin Layer on Base Material] A polyester resin having the following content was coated on one surface of the obtained base material with a gravure coater so as to be 10 g / m ² (absolute dry weight). Coating was performed, and water was smeared on the back surface using a bar coater at a coating amount of 8 g / m ² . Further, the obtained laminated sheet is passed through a pressure nip constituted by a metal roll and an elastic roll, and is subjected to an incidence / injection based on JISZ8741.
The glossiness of the blank paper at the receiving angle of 75 degrees becomes 100%, and JI
The maximum height Rmax based on SK0601 is 2.0 μm
, To prepare an electrophotographic transfer sheet having a basis weight of 140 g / m ² . [Transparent resin layer] 100 parts by weight of polyester resin (trademark: TP220, manufactured by Nippon Synthetic Chemical Company, molecular weight Mn: 16000, glass transition temperature: 70 ° C)

[Evaluation of image quality of electrophotographic transfer sheet] Acolor 93 was applied to the obtained electrophotographic transfer sheet.
5 (manufactured by Fuji Xerox Co., Ltd.), and the gloss unevenness of the image area was visually evaluated, and the blocking property of blank paper was also confirmed. Table 1 shows the test results.

Example 3 An electrophotographic transfer sheet was prepared and evaluated in the same manner as in Example 1. However, the thickness of the transparent resin layer is 18 μm.
m

[0036] In each of Examples 4-6 Examples 4-6, creates a transfer sheet for electrophotography in the same manner as in Example 2, it was evaluated. However, the resin of the transparent resin layer was changed to the following. (Example 4) 100 parts by weight of polyester resin (trademark: WR901, manufactured by Nippon Synthetic Chemical Company, molecular weight Mn: 19000, glass transition temperature: 67 ° C) (Example 5) 100 parts by weight of polyester resin (trademark: ES670, Dainippon Japan) (Ink Chemical Industry Co., Ltd., molecular weight Mn: 6000, glass transition temperature: 35 ° C.) (Example 6) 100 parts by weight of polyester resin (trademark: TP217, manufactured by Nippon Synthetic Chemical Company, molecular weight Mn: 16000, glass transition temperature: 40 ° C.) )

Example 7 An electrophotographic transfer sheet was prepared in the same manner as in Example 2.
evaluated. However, a pigment coating layer was provided on one side of the same support as in Example 2, a transparent resin layer was provided thereon, and an oxidized starch (trade name: Ace A, manufactured by Oji Cornstarch) was further provided on the back side of the support. A substrate coated with the coating solution of above using a bar coater so that the coating amount was 2.0 g / m ² (absolute dry weight) was used. 100 parts by weight of polyester resin (trademark: TP220, manufactured by Nippon Synthetic Chemical Company, molecular weight Mn: 16000, glass transition temperature: 70 ° C)

Example 8 In the same manner as in Example 2, a transparent resin layer was provided, and a transfer sheet for electrophotography was prepared and evaluated. However, a commercially available mirror coat gold having a basis weight of 127.9 g / m ² was used as the substrate. 100 parts by weight of polyester resin (trademark: TP220, manufactured by Nippon Synthetic Chemical Company, molecular weight Mn: 16000, glass transition temperature: 70 ° C)

Comparative Example 1 An electrophotographic transfer sheet was prepared in the same manner as in Example 2.
evaluated. However, in the preparation of the base material, an electrophotographic transfer sheet provided with a transparent resin layer, wherein the glossiness of the white paper on the surface of the base material is controlled to be 30%, the surface roughness Rmax is controlled to be 13 μm, and the transparent resin layer is provided. The surface was controlled so that the white paper glossiness became 85% and the surface height Rmax became 6 μm.

Comparative Example 2 An electrophotographic transfer sheet was prepared in the same manner as in Example 2.
evaluated. However, in the [Preparation and application of coating liquid] step, the composition of the coating liquid was changed to kaolin (average particle diameter: 0.3 μm).
m Trade name: UW-90 Engelhard Co., Ltd.) 10 parts by weight (solid content; the same applies hereinafter), light calcium carbonate (average particle diameter 1.6 μm trade name; TP121 manufactured by Okutama Industry Co., Ltd.) 80 parts by weight, heavy calcium carbonate (Average particle size 0.5
μm (Product name: Hydrocurve K9, Bihoku Powder Chemical Co., Ltd.) Changed to 10 parts by weight, the surface gloss of the base material was controlled to 40%, and the surface height Rmax was controlled to 8 μm. The glossiness of the white paper of the transparent resin layer of the photographic transfer sheet is 80%, and the surface height Rmax is 6%.
It was controlled to be μm.

Comparative Example 3 An electrophotographic transfer sheet was prepared in the same manner as in Comparative Example 1.
evaluated. However, the thickness of the transparent resin layer was 30 μm.

[0042] In each of Comparative Examples 4 to 6 and Comparative Examples 4 to 6 Example 2, except for changing the resin of the transparent resin layer in the following contents, in a similar manner to create a transfer sheet for electrophotography was evaluated . (Comparative Example 4) 100 parts by weight of polyester resin (trademark: UE205, manufactured by Kao Corporation, molecular weight Mn: 37000, glass transition temperature: 59 ° C) (Comparative Example 5) 100 parts by weight of polyester resin (trademark: Z377, Nippon Synthetic Chemical Company) (Comparative Example 6) 100 parts by weight of polyester resin (trade name: T2716, manufactured by Nippon Synthetic Chemical Company, molecular weight Mn: 20,000, glass transition temperature: 90 ° C.)

Evaluation method [ Evaluation of image quality of transfer sheet for electrophotography] An image was recorded on the obtained transfer sheet for electrophotography using Acolor 935 (manufactured by Fuji Xerox Co., Ltd.), and uneven gloss of the image area was visually observed. And the blocking resistance of the white paper was also evaluated. Table 1 shows the test results.

(Evaluation of Unevenness of Gloss on Recorded Image Surface) Acol
The gloss unevenness of the image surface recorded by or935 was visually evaluated, and the degree of the gloss unevenness was visually evaluated according to the following evaluation criteria. (Recording environment: 20 ° C.-65% RH) A: Excellent without gloss unevenness. There is no practical problem and the quality is excellent. ：: good with almost no gloss unevenness No problem in practical use. Δ: There is uneven gloss and slightly inferior. There is a practical problem. X: Many unevenness of gloss is inferior. There is a problem in practical use, and the quality is extremely poor.

(Evaluation of Gloss of Base Material and Transfer Sheet for Electrophotography) Based on JIS Z8741, the blank sheet portion of the base material and the transfer sheet for electrophotography has an incident angle and a light receiving angle of 75%.
The gloss was measured under the condition of degree. Gloss measuring device (model; GL
OSS METER MODEL GM-26D, manufactured by Murakami Color Research Laboratory Co., Ltd.) was used.

(Evaluation of Surface Roughness of Base Material and Transfer Sheet for Electrophotography) Based on JIS K0601, the maximum height Rmax of the surface of the blank portion of the base material and the transfer sheet for electrophotography.
Was measured using a stylus type surface roughness meter. As a measuring device, a surf coder (manufactured by Kosaka Laboratories) was used.

(Evaluation of Blocking Resistance of White Paper) The transparent resin layer and the back surface of the transfer sheet were overlapped, sealed, and subjected to a load of 50 g / cm ² , left in a dryer at 40 ° C. for 24 hours, and then stacked. The alignment was peeled off, the state of blocking was visually evaluated, and the degree of the state was visually evaluated according to the following evaluation criteria. If it is ◎ or ○, there is no practical problem. Also △
If it is x, there is a practical problem. A: No peeling of the transparent resin layer was observed. ：: Peeling of the transparent resin layer is slightly observed. Δ: Peeling of the transparent resin layer is observed. X: The peeling of the transparent resin layer is remarkably observed.

[0048]

[Table 1]

[0049]

The transfer sheet for electrophotography according to the present invention is
An electrophotographic transfer sheet capable of reproducing high-quality images without unevenness in gloss of a recorded image, and is extremely useful in practice.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Ryosuke Nakanishi 2274 Hongo, Ebina-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. Inside

Claims (3)

[Claims] 1. A transparent resin layer formed on at least one surface of a base material and containing a thermoplastic resin as a main component, wherein the number of thermoplastic resins contained in the transparent resin layer is The average molecular weight (Mn) is 5,000 to 20,000, the glass transition temperature is 30 to 85 ° C., the white paper glossiness of 75 ° based on JIS Z8741 on the surface of the base material is 50% or more, and JIS K0
The maximum height Rmax based on JIS K0601 is not more than 10 μm, and the surface of the transparent resin layer has a white paper glossiness of 75 degrees based on JIS Z8741 of 90% or more, and the maximum height Rmax based on JIS K0601 is not less than 90%. 5μ
m or less, wherein the transfer sheet for electrophotography is not more than m. 2. The electrophotographic transfer sheet according to claim 1, wherein the thermoplastic resin is selected from polyester resins. 3. The coating thickness of the transparent resin layer is 3 to 2
The transfer sheet for electrophotography according to claim 1, which has a thickness of 0 µm.