JP3312705B2 - Electrostatic recording paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic recording paper which is developed using a liquid toner comprising resin particles containing or not containing a colorant, a charge controlling agent and most of a liquid aliphatic hydrocarbon. In particular, the present invention relates to an electrostatic recording paper suitable for electrostatic recording by an electrostatic plotter or an ion printer.

[0002]

2. Description of the Related Art Electrostatic recording paper is used for electrostatic recording in which an electrostatic latent image is formed by electrostatic writing means using a stylus electrode, and thereafter visualized by a wet toner.
The electrostatic writing means is mainly used for an electrostatic plotter which outputs a CAD drawing or the like. The electrostatic recording paper usually has a structure in which a conductive layer and a dielectric layer made of resin are sequentially laminated on paper serving as a support, synthetic paper or a polymer film, and a stylus is used for the dielectric layer. An inorganic pigment is added to the dielectric layer in consideration of writing suitability with an electrode, development suitability with negative pressure development, and writing suitability with a pencil or the like. When an electrostatic latent image is formed on an electrostatic recording paper by using an electrostatic plotter, a voltage is applied between the electrostatic recording paper and a conductive layer of the electrostatic recording paper, and the dielectric layer is formed by irregularities on the surface of the dielectric layer. An electrostatic latent image corresponding to the information is recorded on the dielectric layer by the discharge phenomenon using the gap. Therefore, in such an electrostatic recording paper, its dielectric layer is required to maintain insulation without being affected by environmental conditions such as humidity, and after forming an electrostatic latent image. Until the electrostatic latent image is developed, charge retention for holding the electrostatic latent image is required. However, inorganic pigments have excellent suitability for writing with a pencil or the like, but have a problem that they have hygroscopicity and are inferior in aging from the viewpoint of retaining insulation. There is a problem that it is difficult to align, it is difficult to make the dielectric layer surface a uniform mat state, and even to disperse uniformly in the dielectric layer, there is a problem in wettability with resin, There is a problem that much labor is required for uniform dispersion.

When an ion flow printer is used as an electrostatic writing means, the unevenness of the surface of the dielectric layer is not necessary as the writing means. Since the surface is too glossy, when trying to obtain gradation recording, it is necessary to have a surface shape close to coated paper, art paper etc. used in general printing, and to have a surface property close to paper quality In addition, surface properties having irregularities are required.

On the other hand, when an electrostatic latent image is developed with a wet toner, the electrostatic recording paper comes into contact with the wet toner, and the toner adheres only to the portion where the electrostatic latent image is formed, thereby visualizing the electrostatic information. However, when the dielectric layer comes into contact with the charge control agent contained in the liquid toner, the dielectric layer is charged, fogging occurs, and the contrast is reduced. For this reason, a fog is prevented by applying a bias voltage between the electrostatic recording paper and the developing counter electrode, but when a bias voltage is applied, the voltage value is applied to the dielectric layer. The electrostatic latent image is not developed unless it is lower than the potential of the electrostatic latent image to be recorded. When binary recording by ON-OFF is performed, a bias voltage about the development threshold may be applied in accordance with the development characteristics of the toner. However, when performing gradation recording, recording of an electrostatic latent image is performed. The voltage range is reduced, and the gradation is impaired. When the potential range of the electrostatic latent image formed according to the information is low,
There is a problem that the loss of gradation becomes more remarkable.

[0005]

SUMMARY OF THE INVENTION According to the present invention, there is little fogging during development with a wet toner, and the insulating property with time is excellent, and the uniform unevenness of the surface of the dielectric layer can be easily obtained. Another object of the present invention is to provide an electrostatic recording paper capable of performing recording with excellent gradation.

[0006]

According to the present invention, there is provided an electrostatic recording paper comprising:
In an electrostatic recording paper developed using a wet toner comprising a resin particle containing or not containing a colorant, a charge controlling agent and most of a liquid aliphatic hydrocarbon, the electrostatic recording paper is formed on a base paper. A dielectric layer is laminated via a conductive layer,
And the dielectric layer is a resin that does not generate charge even when it comes into contact with the charge control agent (hereinafter, referred to as a low charge resin),
A copolymer resin having styrene as a constitutional unit, an ethylene-vinyl acetate copolymer dispersed in the resin, a polyolefin resin modified to introduce a carboxyl group, a copolymer of ethylene and acrylic acid or methacrylic acid, Alternatively, it is further characterized by comprising one or more resin particles selected from ionomers obtained by crosslinking them and a copolymer of ethylene and an acrylate ester.

Hereinafter, the electrostatic recording paper of the present invention will be described. The low-charge resin is a resin having low charge for both positive and negative polarities in a triboelectric series, and includes, for example, a copolymer resin having styrene as a structural unit, such as a styrene butyl acrylate copolymer and styrene. Butadiene copolymer and the like.

As these low-charge resins, commercially available resins may be used, and as styrene butyl acrylate copolymers, trade names 720, 750 and 77 manufactured by Sanyo Chemical Industries, Ltd.
And styrene butadiene copolymers manufactured by Denka Co., Ltd., trade names CLEAREN 530L, 630L, 73
0L and 750L. These resins generally have low chargeability with respect to the charge control agent. Among them, the styrene butyl acrylate copolymer has excellent low chargeability with respect to many charge control agents in a wet toner described below. Shown and preferred. However, depending on the low-charging resin, the chargeability differs depending on the charge control agent described later. For example, in the case of performing full-color output of four colors of Y, M, C, and K, it is used for each toner. When there are two or more kinds of charge control agents, it is preferable to use a low-charge resin which does not generate charge by any of the charge control agents.

These low-charge resins are soluble at room temperature in hydrocarbon solvents such as benzene, toluene and xylene, and chlorinated hydrocarbon solvents such as tricrene, perchrene and carbon tetrachloride. 30% by weight, preferably 5%
The resin solution has a concentration of from 20% by weight to 20% by weight, and may be dissolved by heating.

Next, resin particles having low solubility in the above-mentioned solvent at room temperature are added to a resin solution in which the low-charge resin is completely dissolved. Such a resin is not particularly limited as long as it is a resin obtained by granulating a resin having low solubility in a solvent at room temperature, but ethylene-vinyl acetate copolymer particles are preferable.

As the ethylene-vinyl acetate copolymer,
By trade name, Ultrasen series manufactured by Toyo Soda Kogyo Co., Ltd., for example, 510X, 515F, 530,537,537L, 537S, 525,
520F, 540,540F, 541,541L, 625,630,630F, 682,627,631,6
33,680,681,635,634,710,720,722,725,751,750,760 etc.
Sumitomo Chemical Co., Ltd. Summit Series, for example, DD
-10, HA-20, HC-10, HE-10, KA-10, KA-20, KA-31, KC-10, KE-1
0, MB-11, RB-11, etc., Evaflex series manufactured by Mitsui Dupont Chemical Co., Ltd., for example, 45X, YW, 150, 210, 220, 25
0,260,310,360,410,420,450,460,550,560, etc. Soaglen series of Nippon Gosei Kogyo Co., Ltd., for example, BH, CH, CI, DH
Soarex series, such as RBH, RCH, RDH, etc.
Takeda Pharmaceutical Co., Ltd. Dumilan series, for example, Dumilan D-219, D-229, D-251S, C-2280, C-2270, C-15
90, C-1570, C-1550 and the like. In addition, Mitsubishi Oil
Yucalon-Eva Co., Ltd., El Pax Co., Ltd. of DuPont, USA, etc. can be used. In addition, N-Polymer manufactured by Nippon Petrochemical Co., Ltd., Tonen Petrochemical Co., Ltd.
Tonen CMP-HA series manufactured by Mitsubishi Petrochemical Co., Ltd., MODIC manufactured by Mitsubishi Petrochemical Co., Ltd., Seixen manufactured by Iron and Steel Chemical Co., Ltd., Ronply manufactured by Mitsui Toatsu Chemicals, Admer manufactured by Mitsui Petrochemical Industry Co., Ltd. , A copolymer of ethylene and acrylic acid, Dow EAA copolymer manufactured by Dow Chemical Co., Yukalon EAA, Mitsubishi Yuka Co., Ltd., Nukuller Mitsui Dupont Chemical Co., Ltd., Akulift Co., Ltd., etc. A copolymer of ethylene and acrylic acid or methacrylic acid, or a so-called ionomer obtained by further cross-linking them, Surlyn manufactured by DuPont of the United States as a trade name,
Addition of BASF EVA1 wax such as Himilan manufactured by Mitsui Polychemicals Co., Ltd., Kobolene latex manufactured by Asahi Dow Co., Ltd., and copolymers of ethylene and acrylic acid esters. ) DPD
These resins may be used alone or as a mixture of two or more.

These resins are soluble in aromatic hydrocarbon solvents such as benzene, toluene, xylene and the like, and chlorinated hydrocarbon solvents such as tricrene, perchrene, carbon tetrachloride and the like when heated. The solubility is reduced, and after being dissolved in these solvents by heating to a temperature range of 40 ° C to 120 ° C, the resin particles are rapidly cooled using water, dry ice, liquid nitrogen, or the like. Can be precipitated.

After dissolving these resins under heating, they are poured into a liquid aliphatic hydrocarbon which is a poor solvent, and
The resin particles may be precipitated by cooling to 15 ° C., but in this case, it is necessary to separate the poor solvent. According to the findings of the present inventors, the size of the precipitated resin particles is affected by the cooling rate. The slower the cooling rate, the larger the average particle diameter, and the faster the cooling rate, the smaller the average particle diameter. The temperature at which granulation occurs is 24 ° C. to about 30 ° C., and the average particle size can be reduced by passing the particles through the material as quickly as possible, that is, by increasing the temperature gradient.

The resin particles thus obtained have a narrow particle size distribution width, show a single peak, have a particle size in the range of 1 μm to 50 μm, and have a D
_One having a single peak of ₅₀ μm to 9 μm is obtained, but may be further finely divided as necessary.

The resin particles may be dispersed in a proportion of 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, per 100 parts by weight of the low charge resin.

In order to disperse such resin particles in a low-charge resin solution, the resin particles may be precipitated and then separated from a solvent and added to the low-charge resin solution. A uniform dispersion can be easily obtained simply by mixing with the above-mentioned low-charge resin solution while stirring the particles and stirring the mixture. Alternatively, the low-charge resin and the resin for forming the resin particles may be heated and dissolved in a solvent at the same time, and then cooled, so that only the resin particles are precipitated, and the coating liquid may be used as it is.

The dispersion obtained in this manner has excellent dispersibility without the resin particles settling in the low-charge resin solution. It is needless to say that the dispersing operation may be performed by ultrasonic irradiation, a high speed disperser, a jet mill, a nibbler, an ong mill, a ball mill, an atomizer, or the like, if necessary.

The dielectric layer may be added with a dye, a viscosity modifier and the like, which are conventionally used in electrostatic recording paper.

A dispersion obtained by dispersing resin particles in a low-charge resin solution is coated on a base paper of a conventional electrostatic recording paper provided with a suitable conductive undercoat layer by a bar coater, a gravure coater, an air knife coater, or the like. Using a slide coater or the like, the coating amount after drying is 0.1 g / m ^{2 to} 40 g / m ^2.
2, preferably ^{1g / m 2 ~20g / m 2} .

The dielectric layer formed in this manner has A
The electric resistance value specified by STM D257 is 1 × 10 ¹⁵
Ω · cm to 1 × 10 ¹⁷ Ω · cm (65% humidity, 25 ° C)
It will be. The dielectric layer in the present invention is made of a low-charge resin and resin particles, and therefore has excellent moisture resistance.

The surface shape of the dielectric layer is such that D ₅₀ is 8 μm.
When resin particles of m to 9 μm are used, the surface roughness is ± 5 μm, and has a uniform uneven shape.

Next, an electrostatic latent image corresponding to the information is formed on the electrostatic recording paper thus created. As an information recording method, an electrostatic plotter, an ion flow printer, or the like can be used.

The electrostatic latent image formed on the electrostatic recording paper is developed with a wet toner containing a charge control agent. The wet toner used in the present invention comprises resin particles containing or not containing a colorant, a charge controlling agent, and most of the liquid aliphatic hydrocarbon.

The liquid aliphatic hydrocarbon is 10 ¹⁰ Ω · cm
It has the above-mentioned volume resistance and is used for the purpose of enhancing the electrical insulation property of the liquid toner, and it is required that the dissolving power for the liquid toner component is relatively small. Deterioration is prevented.

Liquid aliphatic hydrocarbons include liquid n
-Paraffinic hydrocarbons, iso-paraffinic hydrocarbons or mixtures thereof, halogenated aliphatic hydrocarbons and the like. Particularly preferred are branched-chain aliphatic hydrocarbons. For example, it is preferable to use, for example, Isopar G, Isopar H, Isopar K, Isopar L, Isopar M, Isopar V manufactured by Exxon. These have little solubility in the ethylene-vinyl acetate copolymer resin particles described below. For example, the solubility in Isopar H is such that the solubility difference between 25 ° C. and 65 ° C. is 0.0
It is not more than 01 g / ml of solvent. The ratio of the olefin-based resin to the liquid aliphatic hydrocarbon is preferably in a range where the olefin-based resin becomes fluid when mixed and dispersed in the liquid aliphatic hydrocarbon under a heated condition.

The liquid aliphatic hydrocarbon may be present in an amount of 0.01 to 80% by weight, preferably 0.1 to 50% by weight, based on the total weight of the solid component of the wet toner. It is preferable to store in a state of being concentrated at a solid content concentration without change over time. The wet toner at the time of development may be used after being diluted with a liquid aliphatic hydrocarbon so that the solid content concentration is 0.5 to 2% by weight, whereby a preferable printed matter is obtained.

Next, as the resin particles, olefin resin, preferably ethylene-vinyl acetate copolymer resin particles are preferable. As the ethylene-vinyl acetate copolymer,
The same resin as that used in the above-described dielectric layer is used.
The resin particles in the wet toner are prepared by dispersing the resin in a liquid aliphatic hydrocarbon under heating at 40 to 120 ° C., and then adding and mixing a liquid aliphatic hydrocarbon dispersion of a coloring agent as necessary. Then, the resin can be cooled and dispersed to form particles, and the resin can be added to an aromatic hydrocarbon solvent such as benzene, toluene and xylene, or a chlorinated hydrocarbon solvent such as tricrene, perchrene and carbon tetrachloride. After dissolving under temperature,
Put into a liquid aliphatic hydrocarbon cooled to 5 to 15 ° C., and precipitate into particles using a temperature difference and a solubility difference,
Further, the solvent may be replaced with a liquid aliphatic hydrocarbon to disperse the resin particles in the liquid hydrocarbon.

As a cooling method, rapid cooling may be performed using dry ice, liquid nitrogen, or the like. The average particle size of the resin particles is affected by the cooling speed, and the slower the cooling speed, the larger the average particle size. The faster the cooling rate, the smaller the average particle size.
The temperature at which granulation occurs is 24 ° C. to about 30 ° C., and the average particle size can be reduced by passing the particles through the material as quickly as possible, that is, by increasing the temperature gradient.

The mixing and dispersing step performed after cooling is as follows:
Ultrasonic irradiation, high-speed disperser, jet mill, nibbler, ong mill, ball mill, atomizer, etc., can be used to further reduce the resin particles. That is, the particle size of the obtained particles is 0.1 to
In the range of 10 [mu] m, and the D ₅₀ showing an average particle size 0.6
One showing a single peak at 0.8 μm is obtained. Also,
If only the colorant is first milled in a separate step, a wet toner having a sharper particle size can be obtained. Also,
In the case where the polyhydroxycarboxylic acid ester is present in the granulation step, the obtained resin particles have a narrow distribution width of the particle diameter, show a single peak, and have excellent dispersion stability. This is considered to be due to the granulation adjusting function and the dispersing function of the polyhydroxycarboxylic acid ester.

As the charge control agent in the liquid toner, manganese naphthenate, calcium naphthenate,
Zirconium naphthenate, cobalt naphthenate, iron naphthenate, lead naphthenate, nickel naphthenate, chromium naphthenate, zinc naphthenate, magnesium naphthenate,
Manganese octylate, calcium octylate, zirconium octylate, iron octylate, lead octylate, cobalt octylate, nickel octylate, chromium octylate, magnesium octylate, manganese dodecylate, calcium dodecylate, zirconium dodecylate, dodecylate Iron, lead dodecylate, cobalt dodecylate, nickel dodecylate, metal soaps such as chromium dodecylate, zinc dodecylate, magnesium dodecylate, alkyl sulfonates such as sodium dodecylbenzenesulfonate and barium dodecylbenzenesulfonate, lecithin, Examples thereof include phospholipids such as separin, organic amines such as n-decylamine, metal salts of dialkyl sulfosuccinic acid, and metal-containing azo colorants.

In the present invention, in order to reduce fog on the electrostatic recording paper during development, it is necessary to select a combination of these charge control agents and a low-charge resin in the dielectric layer as described above. is there.

The addition amount of the charge control agent may be the minimum amount that exhibits a charge control effect, but is usually 0.01 to 50% by weight in the liquid aliphatic hydrocarbon. Is preferably added to the resin dispersion, but may be added to the colorant dispersion, or a mixture thereof,
It may be added to the mixed liquid after cooling and mixed and dispersed.

In the liquid toner, examples of the coloring agent which is added as necessary include known organic and inorganic pigments and dyes. Is added to In order to reproduce continuous tones of multiple colors equivalent to offset printing, it is necessary that the optical reflection density of each color toner after transfer to a transfer receiving member be 0.7 or more, and in particular, for cyan and black, 1 .
Desirably, it is 0 or more. To make the optical reflection density 0.7 or more for each color, in the case of black and cyan,
10 to 150% by weight based on the same weight as above, 40 to 150% by weight for magenta, and 10 for yellow
The content is preferably set to １００100% by weight. If any of the colors exceeds the above range, background stains are likely to occur after development. The colorant is used in the form of a powder having a particle size of 30 to 150 μm in a secondary aggregation state, and is dispersed in a liquid aliphatic hydrocarbon by ultrasonic dispersion or the like so as to have a predetermined mixing ratio with respect to the resin. Good.

In the wet toner, as a fixing agent, for example, various resins soluble in liquid aliphatic hydrocarbons, for example, modified or unmodified alkyd resins, ordinary acrylic resins, synthetic rubbers, polyalkylene oxides, etc. Polyvinyl acetal (including butyral), vinyl acetate resin and the like can be added. Also, many anionics as dispersants,
A cationic, amphoteric or nonionic surfactant can be added, and a synthetic resin or the like used as the fixing agent can be used as a dispersant.

[0035]

The electrostatic recording paper of the present invention has a dielectric layer composed of a low-charge resin and resin particles which are not compatible with the resin solution used for laminating the resin. In the development using a wet toner, fog can be reduced, and the unevenness of the dielectric layer surface is uniform, so that the gradation is reduced when electrostatic recording is performed by an electrostatic plotter, an ion flow printer, or the like. It can be excellent. Further, the electrostatic recording paper of the present invention has excellent moisture resistance even when stored for a long period of time, and the coating liquid can be made to have excellent dispersion stability even during production. The body layer can be easily manufactured. Hereinafter, examples of the present invention will be described.

[0036]

Example 1 An ethanol solution containing 11% by weight of a quaternary ammonium salt polymer (trade name: Keshistat 6300H, manufactured by Sanyo Chemical Co., Ltd.) was dried at a coating amount of 5.5.
As a 9 g / m ^2, the paper (S- topcoat, Kanzaki Paper (Ltd.), 84.9g / m ²⁾ to form a conductive layer was applied by a gravure reverse coating method.

On the other hand, a coating solution for forming a dielectric layer was prepared as follows.

(Method for producing resin particles) A separate flask equipped with a reflux condenser and a stirring motor was used. Partially saponified ethylene-vinyl acetate copolymer resin (manufactured by Takeda Pharmaceutical Co., Ltd., Dumilan C-2270) … 2.5% by weight ・ Toluene ・ ・ ・ ・ 1.25g of a mixture consisting of 97.5% by weight was charged into a flask, and the mixture was stirred for 1 hour while being heated to about 80 ° C using a water bath and stirred for 1 hour. Was dissolved in toluene and then rapidly cooled with ice water while stirring was continued, whereby translucent particles were precipitated.

FIG. 1 shows the result of measuring the particle size distribution of the obtained particles by using Microtrac-Mark IISRA type (manufactured by Nikkiso Co., Ltd., North and Slop Co.). As can be seen from FIG. 1, the particles obtained have a sharp, single-peak distribution spectrum with a particle size width of 1 μm to 50 μm and an average particle size D ₅₀ of 8.35 μm.

(Composition of coating liquid) Styrene-butyl acrylate copolymer resin (Tg: about 34 ° C., manufactured by Sanyo Chemical Co., Ltd.)
750) After charging 200 g to 4.8 kg of toluene,
After heating to 60 ° C. to dissolve the resin and then cooling to room temperature, the resin particle dispersion prepared above was mixed and stirred to obtain a coating liquid having the following composition.

The composition of the coating liquid is as follows: Styrene-butyl acrylate copolymer resin: 14.25% by weight Resin particles prepared above: 0.75% by weight Toluene: 85% by weight is there.

This coating solution was applied onto the paper having the conductive layer prepared above by a gravure reverse coating method so that the coating amount after drying was 6.56 g / m ^2. Were laminated to form an electrostatic recording paper. FIG. 2 shows the results of measuring the surface roughness using Surftest-211 manufactured by Mitutoyo Corporation. As can be seen from the figure, the surface of the low charging resin layer has a roughness of ± 5 μm and has a uniform unevenness.

[0043]

[Example 2] In Example 1, the composition of the coating liquid was as follows: styrene-butyl acrylate copolymer resin 9.5% by weight Resin particles prepared above 1.5% by weight Toluene An electrostatic recording paper was prepared in the same manner as in Example 1 except that the content was 89% by weight.

[0044]

Example 3 In Example 1, a styrene-butadiene copolymer resin [manufactured by Denka Corporation, Clearen 7] was used instead of the styrene-butyl acrylate copolymer resin in the coating solution.
An electrostatic recording paper was prepared in the same manner as in Example 1 except that the same amount of 50L) was used.

[0045]

Comparative Example 1 The procedure of Example 1 was repeated, except that the same amount of a polyester resin (Toyobo Co., Ltd., Byron RV200) was used instead of the styrene-butyl acrylate copolymer resin in the coating solution. A comparative electrostatic recording paper was prepared.

[0046]

Comparative Example 2 In Example 1, the same amount of vinyl chloride-vinyl acetate copolymer resin (Slec C, manufactured by Sekisui Chemical Co., Ltd.) was used in place of the styrene-butyl acrylate copolymer resin in the coating solution. Except for the above, an electrostatic recording paper for comparison was prepared in the same manner as in Example 1.

(Preparation of Wet Toner) Using a separate flask provided with a reflux condenser and a stirring motor, a metal phthalocyanine pigment (Sumitomo Chemical, Sumika GNO-DP) 5 parts by weight Vinyl acetate copolymer resin (Dumilan C-2270, manufactured by Takeda Pharmaceutical Co., Ltd.) 5 parts by weight Magnesium naphthenate (Nippon Chemical Industry Co., Ltd.) 10 parts by weight Toluene ... 100 parts by weight are put into a flask, and about 80
The mixture was heated and melted at 20 ° C. for 20 minutes, and rapidly cooled with ice water while stirring was continued. As a result, translucent particles were precipitated. When 400 parts by weight of Isopar G was added while stirring was continued, the particles became opaque. When the stirring was stopped, the particles precipitated at the bottom of the container. The supernatant was removed and the addition of Isopar G was repeated to replace the toluene in the solvent with Isopar G to obtain a wet toner (A).

In the above-mentioned method for producing a wet toner,
In place of magnesium naphthenate, the same amount of barium petronate (produced by Witco Chemical Co., Ltd.) is used, and a wet toner (B) is used in the same manner, and magnesium naphthenate (produced by Nippon Chemical Industry Co., Ltd.) Using the same amount of a mixture of lecithin (manufactured by Junsei Chemical Co., Ltd. [magnesium naphthenate: lecithin = 50: 50 (% by weight)]), wet toner (C) and lecithin (Junsei Chemical ( Co., Ltd.) was used in the same amount to similarly prepare a wet toner (D).

The electrostatic recording paper prepared in each of the above Examples and Comparative Examples was formed by forming various electrostatic patterns having a surface charge of 150 V to 0 V using an ion flow printer. The wet toners (A) to (D) were diluted with Isopar G, adjusted to a solid concentration of 1%, used, and developed by a roller developing machine. Developing machine speed is 1m / mi
n. I went in. In Comparative Examples 1 and 2, only the results for the wet toner (B) are shown.

At several places on the surface of the electrostatic recording paper where no electrostatic pattern is formed, the optical reflection density (OD
Value) was measured using Macbeth RD914 (manufactured by Macbeth Co., Ltd.). Table 1 shows the results. Example 1
(S-Topcoat, Kanzaki Paper Co., Ltd., 8
The OD value of 4.9 g / m ² ) itself is 0.02.

[0051]

[Table 1]

As can be seen from the table, the electrostatic recording paper of the present invention has little fog. Further, the electrostatic recording paper of the present invention reproduced various electrostatic patterns having a surface charge of 150 V to 20 V, and was excellent in gradation.

The electrostatic recording paper prepared in each of the above Examples and Comparative Examples was formed with an electrostatic pattern using an electrostatic plotter (EP-4010), and then developed with slits. The optical reflection density (OD) after development was obtained for several places on the surface of the electrostatic recording paper where no electrostatic pattern was formed.
Value) was measured. Table 2 shows the results.

[0054]

[Table 2]

The electrostatic recording paper of the present invention reproduces an electrostatic pattern and, as can be seen from the table, has little fog.

[Brief description of the drawings]

FIG. 1 is a diagram showing a particle size distribution of resin particles used for forming a dielectric layer in the electrostatic recording paper of the present invention.

FIG. 2 is a diagram showing the surface roughness of a dielectric layer in the electrostatic recording paper of the present invention.

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Masayuki Iijima 1-1-1 Ichigaya-Kaga-cho, Shinjuku-ku, Tokyo Inside Dai Nippon Printing Co., Ltd. (56) References JP-A-5-333606 (JP, A) JP-A-5-204190 (JP, A) JP-A-4-50854 (JP, A) JP-A-2-53063 (JP, A) JP-A-60-181747 (JP, A) JP-A-3-136055 ( JP, A) JP-A-57-115550 (JP, A) JP-A-56-132346 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 5/00

Claims (2)

(57) [Claims] 1. An electrostatic recording paper which is developed using a wet toner comprising resin particles containing or not containing a colorant, a charge controlling agent and most of a liquid aliphatic hydrocarbon. Paper is a resin in which a dielectric layer is laminated on a base paper via a conductive layer, and the dielectric layer is a resin that does not generate charge even when it comes into contact with the charge control agent, and comprises styrene.
And copolymer resins in units of ethylene was dispersed in the resin - vinyl acetate copolymer, which was introduced denatured carboxyl polyolefin resin, a copolymer of ethylene and acrylic acid or methacrylic acid, or even their An electrostatic recording paper comprising an ionomer obtained by crosslinking the above, and one or more resin particles selected from a copolymer of ethylene and an acrylic ester. 2. The electrostatic recording paper according to claim 1, wherein the resin in the dielectric layer, which does not generate charge even when contacted with a charge control agent, is a styrene-butyl acrylate copolymer resin.