JPH08262780A - Electrophotographic sheet - Google Patents

Abstract

PURPOSE: To optimize the surface resistances of front and rear sides and to obtain a sheet excellent in image quality and transportability and usable even in full-color copying OHP(overhead projector). CONSTITUTION: An electrically conductive layer 2 and a receiving layer 1 are successively formed on one side of a transparent substrate 3 and a slip layer 4 is formed on the other side. An antistatic layer 5 is formed on the front side of the receiving layer 1 and a detection mark 6 which is made transparent by heating is formed on the rear side of the substrate 3. Cation modified acrylic resin is used in the electrically conductive layer 2. The receiving layer 1 is based on polyester resin using propylene glycol modified bisphenol A as a diol component and fumaric acid as an acid component and fine particles are incorporated. The surface resistances of the front and rear sides are regulated to 10<8> -10<12> Q/ sq. and 10<10> -10<14> Ω/sq., respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic sheet, and more particularly to an OHP (overhead projector) sheet for an electrophotographic copying machine, and more particularly to a sheet suitable for full color copying.

[0002]

2. Description of the Related Art OHP is widely used in lectures, lectures, briefing sessions and the like. And OH used for OHP
To provide an image on the P sheet, a means such as handwriting using oil-based ink or the like, printing, an electrophotographic copying machine or the like is used. Among them, the electrophotographic copying machine can easily obtain a good-looking image, but the OHP sheet provided therewith needs the fixing property of the toner, the transportability of the sheet, and the like. Therefore, the receiving layer is formed on the transparent resin sheet. The provided one is used. Further, in order to obtain toner fixability and transportability, an electrophotographic sheet on which an antistatic agent is applied or a conductive layer is formed has been proposed.

[0003]

However, it is necessary to control the sheet resistance of the front surface and the back surface more than before, and the sheet resistance of the front surface greatly affects the image performance, and the sheet resistance of the back surface greatly affects the transportability. It was generally known to have an effect,
None of the conventional electrophotographic sheets have a good balance of toner fixability and transportability, and especially none suitable for a full-color copying machine that superimposes and fixes four color toners.

For example, in Japanese Unexamined Patent Publication (Kokai) No. 48-81539, in order to improve toner fixability and obtain good sheet transportability, a sheet is coated with a resin solution containing an antistatic agent, and its area resistivity is increased. It discloses that (surface specific resistance) is defined in a specific range. However, the low molecular weight antistatic agent migrates from a dark surface to a thin surface of the treatment, and finally the front surface and the back surface have the same sheet resistance. Further, in order to reduce the resistance value to a target value only by applying the antistatic agent to the surface, it is necessary to increase the concentration of the antistatic agent,
Surface stickiness, fingerprints, etc. occur.

Therefore, in order to reduce the sheet resistance, it is possible to control the electric resistance by using a resin having an antistatic property, for example, a surface treatment with an acrylic conductive agent, without using a low molecular weight antistatic agent. No. 62-238576. According to this technique, since it is a resin,
There is no migration to other surfaces or stickiness, and there is little change over time,
Since the receiving layer is made of an acrylic resin, the wettability with the color toner is poor and a good image cannot be obtained. That is, the portion where the toner is overlapped becomes uneven and scatters the incident light, so that the image becomes cloudy and a graying phenomenon occurs. As described above, in full-color copying machine applications, it is important that the toners of three or four colors are heated and melted and pressure-bonded at the time of heat fixing, so that the receiving surfaces are well wetted and sufficiently overlapped.

As described above, since the resin itself used for the receiving layer usually has no antistatic property, the antistatic agent is contained in the receiving layer or the surface of the receiving layer is coated with the antistatic agent. However, if a low molecular weight antistatic agent is applied as described above, problems such as stickiness occur. Therefore, Japanese Patent Publication Sho 59-4
No. 286, JP-A No. 62-238576 and the like disclose providing a conductive undercoat layer between the receiving layer and the base material. In such a case, the wettability of the toner is improved by using a resin having excellent toner fixing property in the receiving layer. However, when the resistance value is reduced only by the conductive undercoat layer, the target sheet resistance is the surface of the receiving layer which is the upper layer of the layer and is separated from the conductive undercoat layer, so that the resistance value is lowered to the target value. First, it is necessary to add an antistatic agent to the receiving layer or to perform antistatic treatment on the surface of the receiving layer. However, use of the antistatic agent causes problems such as migration to another surface, aging, and stickiness as described above. Further, even if the resistance value is lowered only by the conductive undercoat layer, friction is increased due to the absence of an antistatic agent for assisting slippage on the sheet surface, and sheet conveyance failure such as double feeding occurs.

Regarding the problem of the wettability of the color toner, the present applicant has paid attention to the fact that there are many polyester resins as the binder resin for the color toner, and not the acrylic resin as the receiving layer but the polyester resin. A technique for obtaining excellent toner fixability using a resin has been disclosed (Japanese Patent Application No. 6-36609). However, with the technology disclosed there, the wettability of the toner suitable for full-color copying is satisfied, but the area resistance of the sheet surface has not yet been optimized, and the total performance including transportability is not perfect. I couldn't say.

Therefore, an object of the present invention is to provide an electrophotographic sheet having a good toner fixing property, an excellent image quality and an excellent transportability, and particularly to an OHP sheet, and further an OHP sheet for full car copying. Is to provide a suitable seat.

[0009]

In order to solve the above problems and achieve the object, the electrophotographic sheet of the present invention is
According to the first aspect of the invention, the conductive layer and the receiving layer are sequentially formed on one surface of the base material, and the slip layer is formed on the other surface of the base material. The invention of claim 2 is the same as the invention of claim 1, except that an antistatic treatment is applied to the receiving layer. The invention of claim 3 is different from the invention of claim 1 or 2 in that
The area resistance of the front surface is 10 ⁸ to 10 ¹² Ω / sq. In addition, the invention of claim 4 is, in comparison with the invention of any one of claims 1 to 3, an area resistance of a back surface of 10
^The configuration is ¹⁰ to 10 ¹⁴ Ω / sq. In addition, claim 5
The invention according to any one of claims 1 to 4 is 50 in the conductive layer with respect to the total resin component constituting the layer.
˜100 wt% cation-modified acrylic resin is contained. Further, the invention of claim 6 relates to claims 1 to
The slip layer according to any one of 5 above,
It is made of acrylic silicone resin.

The invention of claim 7 is suitable for the purpose of viewing a recorded image by utilizing transmitted light.
In the invention described in any one of 6), the base material is transparent. Further, the invention of claim 8 relates to claims 1 to 7.
In the invention described in any one of the items 1 to 3, the receiving layer is configured to have a polyester resin containing modified bisphenol A as a diol component as a main component. The invention of claim 9 is
In addition to the invention according to any one of claims 1 to 8, the modified bisphenol A is propylene glycol modified bisphenol A. Further, the invention of claim 10 is different from the invention of claim 8 or 9 in that the acid component is fumaric acid.

The invention of claim 11 relates to claims 1 to 1.
0. The invention according to any one of 0, wherein the receptive layer has organic fine particles as fine particles having an average particle diameter of 0.1 to 10 μm or /
And a structure containing inorganic fine particles. In addition, claim 1
According to a second aspect of the present invention, the invention according to any one of the first to eleventh aspects has a detection mark which becomes transparent by heating.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing an embodiment of the electrophotographic sheet 7 of the present invention. In the figure, an electrophotographic sheet 7 includes a conductive layer 2 formed on one surface (= front surface) of a base material 3, a receiving layer 1 formed on the conductive layer 2, and the base material 3 described above. And the slip layer 4 formed on the other surface (= rear surface) of the. 2 is a longitudinal sectional view showing another embodiment of the electrophotographic sheet 7 of the present invention. In the figure,
The antistatic treatment layer 5 is provided on the surface of the receiving layer 1, and the detection mark 6 is provided on a part of the back surface of the substrate 2. Hereinafter, each layer will be sequentially described, and then the optimum sheet resistance of the surface will be described.

First, as the base material 3, when the electrophotographic sheet 7 is an OHP sheet or the like and a recorded image is observed by transmitted light, a thermoplastic material having transparency, heat resistance, dimensional stability and rigidity is used. Those formed of resin are preferable. Specifically, a polyethylene terephthalate resin, a polycarbonate resin, an acrylic resin, a polyvinyl chloride resin, a polypropylene resin, a polystyrene resin, a polyethylene resin, a cellulose diacetate resin, a cellulose triacetate resin, etc., having a thickness of about 10 to 250 μm, preferably 50-
A film or sheet having a thickness of about 180 μm can be used. Of these, polyethylene terephthalate resin, polyvinyl chloride resin, polypropylene resin, and cellulose triacetate resin are preferable from the viewpoint of the above performance. Further, for the purpose of observing a recorded image by reflected light, it is preferable that these resin sheets or films are opaque such as white due to addition of a coloring agent or the like. In this case, the base material may be paper such as synthetic paper or coated paper. In addition, a semi-transparent base material can be used for lighting purposes. The surface of the base material 3 may be subjected to a known easy-adhesion treatment such as a primer treatment or a corona discharge treatment for the purpose of improving the adhesion to the layer formed on the base material 3.

The conductive layer 2 formed on the base material 3 may be formed by containing an antistatic agent in a resin. However, when the antistatic agent is used, it diffuses and migrates with time, and the sheet resistance is increased. It is preferable to mainly form a resin having an antistatic property because the value changes and is not stable, and the surface is apt to become sticky. If the resin has antistatic performance,
Although it is not particularly limited as long as it has adhesiveness to the base material and the receiving layer and is transparent for OHP use, a cation-modified acrylic resin is preferable. The conductive layer may be formed only by the cation-modified acrylic resin, but in order to appropriately adjust the adhesion, the sheet resistance, etc., another resin, for example, an acrylic resin, a polyester resin,
You may mix resin components, such as a vinyl chloride type resin, a cellulose type resin, and polyvinyl alcohol. In addition, the amount of the cation-modified acrylic resin is preferably in the range of 50 to 100% by weight based on the total amount of the resin in the conductive layer. Fifty
If it is less than wt%, the resistance value does not decrease to the desired sheet resistance. The conductive layer is formed by forming a coating solution containing the above resin component by a known printing means such as gravure printing or silk screen printing, or a known coating means such as gravure coating, and the thickness is 0 when dried. It is preferably about 1 to 5 μm. If the thickness is too thick, the sheet resistance does not decrease and the economy is poor, and if it is too thin, the desired effect of the conductive layer cannot be obtained.

The receiving layer 1 formed on the conductive layer 2 has a toner fixing property and is particularly suitable for full color copying machines.
For HP applications, a resin having excellent wettability of color toner is preferable. Therefore, an acrylic resin or the like can be used as the receiving layer, but from the viewpoint of the above performance, the polyester resin is preferable, and among them, the specific polyester resin disclosed in Japanese Patent Application No. 6-36609 by the applicant is preferable.

That is, as the polyester resin, a polyester resin using modified bisphenol A modified with ethylene glycol or propylene glycol represented by the chemical formula 1 as a diol component has excellent toner fixing property. Further, the chemical formula 2 is the modified bisphenol A.
Represents a propylene glycol-modified bisphenol A which is a specific compound of.

[0018]

Embedded image

[0019]

Embedded image

On the other hand, as the acid component of the polyester resin,
There is no particular limitation, and for example, fumaric acid, phthalic acid, terephthalic acid, isophthalic acid, maleic acid, succinic acid, adipic acid, citraconic acid, itaconic acid, sebacic acid, malonic acid, hexacarboxylic acid and the like can be used.

Among such polyester resins, propylene glycol-modified bisphenol A represented by the above chemical formula 2
The resin using fumaric acid as an acid component has good compatibility with the binder resin of the toner,
The toner fixability and toner wettability are good, and a good copy image is provided.

In addition to the above polyester resin, other resin may be used in combination in the receiving layer 1. For example, polyolefin resin such as polyethylene and polypropylene,
Vinyl chloride resin, vinylidene chloride resin, vinyl acetate resin, vinyl chloride-vinyl acetate copolymer, acrylic resin such as polyacrylic acid ester, polystyrene resin, polyamide resin, olefins such as ethylene and propylene, and other polymerizable monomers Copolymer of ethylene, cellulose,
Cellulosic resins such as cellulose acetate, ionomers,
Polycarbonate resin, polyethylene terephthalate,
Polyester resins other than the above, such as polybutylene terephthalate.

If the receiving layer 1 contains either or both of the organic fine particles and the inorganic fine particles, the transportability can be improved. Examples of the organic fine particles include fine particles made of an organic resin such as a tetrafluoroethylene resin, a fluorine-based resin such as an ethylene-tetrafluoroethylene copolymer, a polyethylene resin, a polystyrene resin, an acrylic resin, a polyamide resin, and a benzoguanamine resin. . on the other hand,
Examples of the inorganic fine particles include silica, colloidal silica, alumina, kaolin, clay, calcium carbonate, talc, titanium dioxide and calcium carbonate. The average particle size of the fine particles to be contained is preferably in the range of 0.1 to 10 μm. If the average particle size is less than 0.1 μm, the desired effect cannot be obtained sufficiently, and if it exceeds 10 μm, image bleeding occurs or the transparency when used for OHP is reduced, such being undesirable. The content of the fine particles is preferably in the range of 0.1 to 10% by weight based on the total amount of the resin for forming the receiving layer. When the content is too large, the transparency is lowered, and particularly when transparency is required, the upper limit of the content is preferably 3% by weight in order to suppress the haze to 10 or less. Further, if the content is too small, the desired effect of improving the transportability cannot be obtained.

In addition to the above-mentioned fine particles, various additives such as surfactants, antistatic agents, waxes and oils may be mixed and used in the receiving layer within a range that does not impair the effects of the present invention. The formation of the receiving layer is carried out by applying a coating liquid containing the above-mentioned resin components and other fine particles, various additives, etc., if necessary, by a known printing means such as gravure printing or silk screen printing, or a known coating such as gravure coating. It is formed by a means and has a thickness of about 1 to 10 μm when dried.

The slip layer 4 is formed on the back side of the base material,
It improves transportability and also has an effect as a curl prevention layer for the conductive layer and the receiving layer on the surface side of the substrate. As the slip layer, an acrylic resin, a modified acrylic resin, a polyester resin, or the like containing each antistatic agent can be used, but the use of the antistatic agent improves the transportability, but does not cause surface stickiness or stickiness. It is not preferable because it changes over time. In this respect, the acrylic silicone resin, which does not require the combined use of an antistatic agent, exerts an excellent effect. The slip layer is formed by forming the resin coating liquid by a known printing means or a known coating means in the same manner as the conductive layer and the receiving layer,
A sufficient effect can be obtained if the thickness of the slip layer is about 0.01 to 1.0 μm. In the slip layer, a lubricant, organic fine particles, inorganic fine particles and the like may be mixed and used, if necessary, within a range not departing from the object of the present invention.

The antistatic treatment layer 5 applied to the surface of the receiving layer 4 is applied when it is necessary to further reduce the sheet resistance of the surface of the receiving layer lowered by the conductive layer. As the antistatic treatment layer, as an antistatic agent, for example, a quaternary ammonium salt, a cationic antistatic agent such as a polyamine derivative, an anionic antistatic agent such as an alkyl phosphate, a nonionic antistatic agent such as a fatty acid ester, etc. Is used as a coating liquid with a solvent, and this is formed by a known coating means such as gravure coating to a coating amount of about 0.1 g / m ² when dried. Although a part of the applied antistatic agent penetrates into the receptive layer and exerts its effect there, a small amount of the antistatic agent is added to the receptive layer forming coating solution from the beginning when the receptive layer is formed. Good.

The detection mark 6 is a mark for making front and back distinction before copying, which is made transparent by heat when fixing the copying machine. The detection mark 6 is provided on the receiving layer on the front surface of the sheet, or
It is formed between the slip layer on the back side of the sheet and the base material, on the back side of the slip layer, or the like at a position that does not interfere with the formation of the recorded image, for example, at the peripheral edge of the sheet. As the detection mark, a conventionally known white detection mark, or the applicant of the present application, Japanese Patent Application No.
The silver-colored detection mark disclosed in No. 329850 was used. However, since the detection mark is not necessary when the original for OHP is used, the detection mark which becomes transparent by the fixing heat of the copying machine is more convenient because it does not disturb the projected image. As the detection mark which becomes transparent due to such heating, various types of transparent marks can be used. For example, it is an opaque porous resin layer disclosed in JP-A-3-170944, and the layer is a method of foaming a foaming agent to make it porous after being applied to a sheet, and mixing a hydrophobic resin and an extractable resin. After forming the layer, there is a method of making the traces of the extractable resin extracted with water or a solvent into voids to make them porous. Further, by the method disclosed in Japanese Patent Application No. 6-150338 by the present applicant, a method of using a good solvent having a low boiling point and a poor solvent having a high boiling point as a solvent for dissolving a resin to make it porous during a coating film drying process, etc. Good.

The resin component used in the detection mark disclosed in the above-mentioned Japanese Patent Application No. 6-150338, which is transparent by heating with a good solvent / poor solvent, is an acrylic resin, a polyester resin, a vinyl chloride-vinyl acetate copolymer. Etc. can be used. The glass transition temperature of these glass transitions is in the range of 30 to 150 ° C. so that they become transparent by the heat of fixing in the copying machine.
Particularly, the range of 50 to 130 ° C. is good in terms of storage stability and suitability for heat transparency. Further, a combination of a good solvent and a poor solvent for these resins is appropriately selected depending on the resin used, for example, as a good solvent for the organic solvent-soluble resin, acetone, methyl ethyl ketone, ketones such as cyclohexanone, ethyl acetate, Esters such as butyl acetate, aromatic hydrocarbons, alcohols, etc., as a poor solvent, aliphatic hydrocarbons, aromatic hydrocarbons, hydrocarbon solvents such as terpene hydrocarbons, halogenated hydrocarbons,
There are alcohols.

The detection mark which becomes transparent by heating is
The ink made of the above resin is formed by a known printing means such as gravure printing or silk screen printing. The thickness of the detection mark is usually about 0.5 to 10 μm. Further, in the case of forming the detection mark on the back surface, it is preferable that the detection mark is formed between the slip layer and the base material and the entire back surface is used as the slip layer from the viewpoint of transportability.

Next, the sheet resistance of the front surface and the back surface, which is a main characteristic of the electrophotographic image-receiving sheet of the present invention, will be described.

In the present invention, since the conductive layer is provided under the receiving layer and the slip layer is provided on the back surface of the substrate, the sheet resistance [Ω / sq] (= [Ω / □]) of the front surface and the back surface is obtained. Since each can be controlled independently to the optimum value, the resistance value can be the best for both performances of image quality and transportability. The sheet resistance of the front surface greatly affects the toner fixability, and the sheet resistance of the back surface greatly affects the transportability.

The sheet resistance of the front surface is 1 × 10 ⁸ to 1 ×
The range of 10 ¹² Ω / sq is preferable, and 1 is more preferable.
A range of × 10 ⁹ to 1 × 10 ¹¹ Ω / sq is preferable. If the sheet resistance is lower than 1 × 10 ⁹ Ω / sq, image defects (missing) are likely to occur. Conversely, if the sheet resistance exceeds 1 × 10 ¹¹ Ω / sq, image defects (lack of density), static electricity generation and slippage are insufficient. Due to this, conveyance failure is likely to occur. Also, such as less than 1 × 10 ⁹ Ω / sq,
When using an antistatic agent to lower the resistance value,
Surface slime and fingerprints are likely to occur. On the other hand, the sheet resistance of the back surface is preferably in the range of 1 × 10 ¹⁰ to 1 × 10 ¹⁴ Ω / sq, and more preferably 1 × 10 ¹¹ to 1 × 10 ¹³ Ω /.
Good sq range. If the sheet resistance is lower than 1 × 10 ⁹ Ω / sq, image defects (dropouts) are likely to occur, and conversely, 1 × 10
^If it exceeds ¹¹ Ω / sq, defective images (insufficient density), and static electricity or insufficient lubricity tend to result in defective conveyance. It is desirable that the sheet resistance of the front surface is lower than the sheet resistance of the back surface by about 10 ² Ω / sq from the viewpoint of transferability (mechanical suitability) of the toner.

The sheet resistance of the front surface and the back surface is determined by the receptive layer,
The conductivity of the conductive layer can be controlled within a desired range by appropriately adjusting the conductivity of the conductive layer, the base material, the slip layer, and the like, and the ratio of the resin mixed with the conductive resin in the conductive layer. For example, if the thickness of the conductive layer is increased, the sheet resistance decreases. Further, the magnitude of the distance between the front surface or the back surface and the interface between the conductive layer and the sheet resistance can be controlled in the opposite relationship. If the thickness of the conductive layer is set according to the sheet resistance of the back surface and the sheet resistance of the front surface deviates from the appropriate value, increase the thickness of the receiving layer if it falls below the target value. On the contrary, if it is larger than the target value, the surface of the receptor layer may be subjected to antistatic treatment with an antistatic agent. Furthermore, even when antistatic treatment is required in this way,
In the electrophotographic image-receiving sheet of the present invention, the surface resistance of the receiving layer is lowered to a moderate level due to the effect of the conductive layer, so that the treatment concentration of the antistatic agent can be made thin, and there is no stickiness and the slip layer on the back surface is also present. The silicone can be treated to prevent migration of the antistatic agent. Also, by treating the back surface with silicone using an acrylic silicone resin or the like, the slipperiness obtained by the antistatic agent can be imparted, and the transportability is improved.

[0034]

In the electrophotographic sheet of the present invention, the conductive layer interposed between the base material and the receiving layer lowers the sheet resistance of the front surface and the sheet resistance of the back surface to the desired values. And
Along with this sheet resistance, the slip layer exhibits good transportability. By the antistatic treatment of the surface of the receiving layer, the sheet resistance of the front surface can be easily controlled to a desired value. By setting the sheet resistance of the front surface and the back surface within a predetermined range, both excellent toner fixability and transportability can be reliably obtained. Further, by using a predetermined amount of the cation-modified acrylic resin in the conductive layer, optimum sheet resistance can be obtained. The slip layer made of acrylic silicone resin realizes a good transportability together with an optimum sheet resistance value.

Further, by making the base material transparent, the electrophotographic image-receiving sheet can be used for OHP applications. Further, by using a specific polyester resin for the receiving layer, excellent wettability and fixability can be obtained especially for a color toner for full color copying, and a high quality copied image can be obtained. Further, the organic fine particles and the inorganic fine particles having a specific average particle diameter contained in the receiving layer realize excellent transportability. Further, the detection mark which becomes transparent by heating makes it easy to visually distinguish the front and back of the sheet and becomes transparent after copying so that it does not interfere with image projection of OHP or the like.

[0036]

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples. In the text, "parts" or ratios are based on weight unless otherwise specified, and also based on solid content.

Examples and comparative examples are prepared by using the following various substrates, receiving layer coating liquid, conductive layer coating liquid, slip layer coating liquid, antistatic coating liquid and detection mark ink. I made a sheet for electrophotography.

(1) Receptive layer

Receptor layer coating liquid A Polyester resin 30 parts (polymer of fumaric acid and propylene glycol-modified bisphenol A, glass transition temperature = 60 ° C., softening point = 100 ° C.) Silica fine particles (average particle size 5 μm) 15 parts Methyl ethyl ketone 35 parts Toluene 35 parts

Receptor layer coating liquid B Polyester resin 30 parts (Polymer of succinic acid and triethylene glycol modified bisphenol A, glass transition temperature = 60 ° C., softening point = 100 ° C.) Methyl ethyl ketone 35 parts Toluene 35 parts

(2) Conductive layer

Conductive layer coating liquid A Conductive resin (cation-modified acrylic resin) 10 parts (Soken Chemical Co., Ltd., Elecond PQ-50B) Methyl ethyl ketone 15 parts Toluene 15 parts

Conductive layer coating liquid B Conductive resin (cation-modified acrylic resin) 35 parts (Konishi Co., Ltd., Bondip-P base compound, solid content: 30%) Curing agent (epoxy resin) 35 parts (Konishi Co., Ltd. ), Bondip-P curing agent, solid content: 7%) Isopropyl alcohol 20 parts Water 10 parts

(3) Base material

Substrate A Transparent polyethylene terephthalate film (Toray Industries, Inc., Lumirror T-60, thickness 100 μm) Substrate B Both sides antistatic transparent polyethylene terephthalate film (Toray Industries, Inc., Lumirror U-94, thickness 125 μm) ) Substrate C Both-side antistatic white polyethylene terephthalate film (Toray Industries, Inc., Lumirror E-22, thickness 100 μm)

(4) Slip Layer Slip Layer Coating Liquid Acrylic Silicone Resin (Cymac US-450, manufactured by Toagosei Co., Ltd.) 1 part Isopropyl alcohol 25 parts Water 25 parts

(5) Antistatic treatment

Antistatic coating liquid A Antistatic agent (TB-34, manufactured by Matsumoto Yushi-Seiyaku Co., Ltd.) 1 part Isopropyl alcohol 2000 parts

Antistatic coating liquid B Antistatic agent (TB-34 manufactured by Matsumoto Yushi-Seiyaku Co., Ltd.) 1 part Isopropyl alcohol 500 parts

(6) Detection mark

Ink A for detection mark (disappearing mark) Vinyl chloride-vinyl acetate copolymer 18 parts (DENKALAC # 1000A manufactured by Denki Kagaku Kogyo Co., Ltd.) Lubricants (carnauba wax) 5 parts (Koyo Chemical Co., Ltd.) Manufactured, CR-8, particle size 5 μm) good solvent (acetone) 42 parts poor solvent (n-butanol) 35 parts

Ink for detection mark B (silver mark) aluminum paste (Spa-2173, Showa Denko KK) 12 parts Titanium oxide (rutile type) 20 parts Microsilica (Syroid 162, Fuji Silysia KK) 5 Part Urethane resin (Dainippon Ink and Chemicals, Inc., IPDI type) 10 parts Polyethylene wax 2 parts Carbon black 2 parts Methyl ethyl ketone 27 parts Toluene 27 parts

The detection mark ink was formed by gravure printing, the thickness of the receiving layer (when dried, the same applies hereinafter) was 3 μm, the detection mark was 3 μm, the thickness of the slip layer was 0.1 μm or less, and the thickness of the antistatic treatment layer was 0. The coating amount is shown in Tables 1 and 2 for the thickness of the conductive layer.

Evaluation criteria

Sheet resistance : The sheet resistance [Ω / sq] was measured under the environment of 23 ° C. and 60% RH.

Resistance change over time : 1 kg / A4 (= 1.6 g / cm) with the front and back surfaces of an A4 size sheet stacked
The change in sheet resistance of the front surface and the back surface after storage at 50 ° C. for 1 week under the load of ² ) was measured and evaluated according to the following criteria. ⊚: Almost no change. ◯: Change about 1/2 power (decrease). X: Change of one power or more (decrease).

Stickiness (front surface) : Evaluation was performed with a tentacle. ⊚: No stickiness at all. ○: Don't worry about stickiness. X: There is stickiness.

Fingerprint adhesion (front surface ): Evaluation was performed with a tentacle. ⊚: No trace of adhesion. ○: A little adhered, but it is not a concern. X: Adheres clearly.

Image performance : A color chart was copied by a full color copying machine CLC-200 manufactured by Canon Inc., projected by an overhead projector, and visually judged. Image grayed out ; image is clean. ×: The image is full. Image density decrease ○; None. X: Yes

Friction coefficient : According to JIS P8147, the friction coefficient between the front surface and the back surface was measured.

Conveyance performance : Ten sheets were set in a manual feed tray of a full-color copying machine Acolor 635 manufactured by Fuji Xerox Co., Ltd., and continuous copying was performed to evaluate the presence or absence of double feeding. ○: No double feeding. ×: There is double feeding.

[0062] The evaluation results of the evaluation results in Example Table 1, Table 2 shows the evaluation results of Comparative Examples.

[0063]

[Table 1] *: The coating amount of the conductive layer is g / m ² .

[0064]

[Table 2] *: The coating amount of the conductive layer is g / m ² .

[0065]

According to the electrophotographic sheet of the present invention, the sheet resistance of the front surface and the sheet resistance of the back surface can be independently set in the optimum ranges, and excellent image quality and transportability can be obtained. That is, by the conductive layer interposed between the base material and the receiving layer and the slip layer on the back surface of the base material, the sheet resistance of the front surface and the sheet resistance of the back surface can be independently designed to have desired sheet resistance, and a good toner is obtained. Excellent image quality due to fixability and toner wettability, and excellent transportability can be obtained at the same time. Furthermore, by performing antistatic treatment on the surface of the receiving layer, it becomes easy to control the sheet resistance of the front surface according to desired characteristics.
By setting the area resistance of the front surface to be within a predetermined range and the area resistance of the back surface to be within a predetermined range, both excellent toner fixability and transportability can be reliably obtained. Further, by using a predetermined amount of the cation-modified acrylic resin in the conductive layer, optimum sheet resistance can be obtained. Further, the slip layer made of acrylic silicone resin provides good transportability and sheet resistance.

By using a transparent base material, OHP
A sheet with excellent use can be obtained. Further, by using a specific polyester resin having a modified bisphenol A such as propylene glycol modified bisphenol A as a diol component and fumaric acid as an acid component in the receiving layer, the wettability to a color toner for full color copying and toner fixing The quality is improved, and a high-quality full-color copy image is obtained. In addition, by incorporating organic fine particles or inorganic fine particles having a specific average particle diameter in the receiving layer, excellent transportability can be obtained.
Further, by providing a detection mark that becomes transparent by heating, it becomes easy to visually distinguish the front and back of the sheet, and since it becomes transparent after copying, it does not interfere with image projection of OHP or the like.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of an electrophotographic sheet of the present invention.

FIG. 2 is a longitudinal sectional view showing another embodiment of the electrophotographic sheet of the present invention.

[Explanation of symbols]

 1 Receptive Layer 2 Conductive Layer 3 Base Material 4 Slip Layer 5 Antistatic Treatment Layer 6 Detection Mark 7 Electrophotographic Sheet

Claims (12)

[Claims] 1. A sheet for electrophotography, comprising a conductive layer and a receiving layer sequentially formed on one surface of a substrate, and a slip layer formed on the other surface of the substrate. 2. The electrophotographic sheet according to claim 1, wherein an antistatic treatment is applied to the receiving layer. 3. The area resistance of the front surface is 10 ⁸ to 10 ¹² Ω
The sheet for electrophotography according to claim 1 or 2, wherein the sheet is / sq. 4. The sheet resistance of the back surface is 10 ¹⁰ to 10 ¹⁴ Ω / s.
The electrophotographic sheet according to any one of claims 1 to 3, which is q. 5. The conductive layer contains 50 to 100% by weight of a cation-modified acrylic resin with respect to the total resin content of the layer, and the conductive layer contains the cation-modified acrylic resin.
The electrophotographic sheet according to the item. 6. The electrophotographic sheet according to claim 1, wherein the slip layer is made of an acrylic silicone resin. 7. The electrophotographic sheet according to claim 1, wherein the base material is transparent. 8. The electrophotographic sheet according to claim 1, wherein the receiving layer contains a polyester resin containing modified bisphenol A as a diol component as a main component. 9. The electrophotographic sheet according to claim 8, wherein the modified bisphenol A is propylene glycol modified bisphenol A. 10. The electrophotographic sheet according to claim 8, wherein the acid component is fumaric acid. 11. The receiving layer has an average particle size of 0.1 to 10 μm.
The electrophotographic sheet according to any one of claims 1 to 10, characterized in that the fine particles of (1) are contained as organic fine particles and / or inorganic fine particles. 12. The electrophotographic sheet according to claim 7, which has a detection mark which becomes transparent when heated.