JPH0922138A - Electrophotographic direct-lithographic recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording medium capable of easy control of electric conductivity, not causing the scattering of a toner even under any conditions of humidity change and giving a clear image and to obtain a lithographic printing plate. SOLUTION: In this recording medium obtd. by forming an image receiving layer on one side of a substrate with an electrically conductive layer in-between, the electrically conductive layer is made of an electrically conductive compsn. contg. sulfonated polyaniline in which the amt. of sulfonic acid groups bonded to arom. rings is >=10% of the amt. of the arom. rings and the surface resistance of the electrically conductive layer is 10<9> -10<14> Ω/sq. at 15-95% relative humidity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic direct-writing type recording medium. More specifically, the conductive layer does not have humidity dependency, and the conductivity is excellent in control and stability. The present invention relates to an electrophotographic direct drawing type lithographic printing plate excellent in properties and the like, an electrophotographic direct drawing type recording label and the like.

[0002]

2. Description of the Related Art Conventionally, paper, a plastic film provided with an image receiving layer, or synthetic paper has been used as an electrophotographic direct-writing type recording medium, and an ordinary electrophotographic copying machine (PPC) or laser beam printer (LBP) is used. A method of forming a toner image and fixing the toner image is performed. It is widely used for general records and record labels. When a lithographic printing plate is prepared by using this recording method, the original plate after image formation is treated with an etchant to desensitize the non-image area, and then applied to a lithographic printing machine to produce a large number of printed matter. Served to make. In direct-writing recording by such an electrophotographic system, there are problems of so-called background stains in which toner adheres to non-image areas and so-called toner scattering in which toner adheres to the periphery of image areas. Nevertheless, it was a difficult problem to solve especially when a plastic film or synthetic paper was used as the recording medium. Further, when a lithographic printing plate is prepared by this method, the one using paper as a support has poor water resistance and poor dimensional stability, and thus often causes problems during printing, while a plastic or a support is used. When synthetic paper is used, there is a problem in that background stains and toner flying are significantly increased, which affects the quality of printed matter. Therefore, the surface resistance of the conductive layer has been controlled,
As the conductive layer, when a polymer conductive agent is used, the conductivity changes due to humidity, and when an inorganic conductive agent is used, there is no change due to humidity, but it is difficult to control the conductivity,
There has been a problem that stable image characteristics cannot be obtained.

[0003]

SUMMARY OF THE INVENTION The present invention was devised to solve the above-mentioned problems of the prior art. The purpose of the present invention is to prevent toner from flying, to prevent the conductive layer from being dependent on humidity, and to provide a conductive material. It is an object of the present invention to provide an electrophotographic direct-writing type recording medium capable of obtaining a clear image by excellent control of stability and stability.

[0004]

The present invention provides an electrophotographic direct writing type recording medium in which an image receiving layer is provided on one surface of a support through a conductive layer, the conductive layer being bonded to an aromatic ring. A conductive composition containing a sulfonated polyaniline having a sulfonic acid group content of 10% or more based on the aromatic ring,
Further, the electrophotographic direct drawing type recording medium is characterized in that the surface resistance value of the conductive layer is 10 ⁹ to 10 ¹⁴ Ω / □ at a humidity of 15 to 95% RH.

The support in the present invention is paper or a plastic film, and may be paper impregnated with plastic or coated with plastic. The plastic film is made of a single polymer such as polyester, nylon, polypropylene, or polyethylene.
Alternatively, a mixture of them or a laminate of them may be used. In particular, the void-containing polyester film obtained by stretching the sheet-like material obtained by mixing polyester and the polyester with an incompatible thermoplastic resin at least uniaxially, water resistance, dimensional stability, handleability, etc. It is preferable from the point.

The image receiving layer in the present invention is a layer in which inorganic and / or organic particles are dispersed in a binder.
When used as an electrophotographic direct-writing type recording medium planographic printing plate, it is preferable that the image receiving layer contains ZnO particles having an average particle size of 0.2 to 0.9 μm as particles forming the hydrophilic layer. It is preferable to include inorganic particles (preferably silica particles) having an average particle diameter of 2 to 10 μm. The projections and depressions on the surface of the image receiving layer have a projection number of 200 to 1000 / mm ² when the height from the center line is 2 μm, and a projection number of 40 to 400 when the height from the center line is 6 μm.
Is preferably pieces / mm ^2, further, the height from the center line projections number when the 2 [mu] m 350 to 850 pieces /
a mm ^2, and number of projections at a height from the center line 6μm is more preferably 70 to 250 pieces / mm ^2. If the number of protrusions is less than this range, the toner is likely to be crushed, and if the number of protrusions is greater than this range, the toner does not go into the gaps between the protrusions and the toner is easily crushed, and the background stain becomes conspicuous.

The conductive composition containing sulfonated polyaniline used in the conductive layer of the present invention means a sulfonated polyaniline having a sulfonic acid group bonded to an aromatic ring of 10% or more based on the aromatic ring, a solvent, and Conductivity comprising amines and / or quaternary ammonium salts and a water-soluble or water-dispersible copolyester having a sulfonic acid group and / or its alkali metal salt bonded as a binder or a hydrophilic polymer such as polyvinyl alcohol It is a composition.

As the sulfonated polyaniline, at least one compound selected from the group consisting of aniline, aniline derivatives and phenylenediamines is copolymerized with an aminobenzenesulfonic acid compound, and then sulfonated. The aniline-based copolymer sulfonate obtained by the above, and the aniline obtained by copolymerizing at least one compound selected from the group consisting of aniline, aniline derivatives and phenylenediamines with an alkoxy group-substituted aminobenzene sulfonic acid compound A sulfonated copolymer is suitable as a basic material for the conductive composition of the present invention. Further, in terms of improving the coating property, spreadability, and hardness of the coated body of the conductive composition of the present invention, the combined use of the copolymerized polyester containing 5-sulfoisophthalic acid unit in an amount of 1 mol% to 20 mol% is further preferable. It is suitable.

Here, the aniline derivative is a compound in which hydrogen of aniline is substituted with an alkyl group, an aryl group, an alkyl ether group, a sulfonic acid group or the like. Examples thereof include N-methylaniline, N-ethylaniline, N
Examples thereof include N-alkylanilines such as -n-propylaniline, N-iso-propylaniline, Nn-butylaniline and N-tertbutylaniline, and aminoanisole. As phenylenediamines, phenylenediamine, N-phenylphenylenediamine, N, N'-diphenylphenylenediamine, N-
Aminophenyl-N'-phenylenediamine and the like can be mentioned.

The alkoxy group-substituted aminobenzenesulfonic acids are aminoanisolesulfonic acids, examples of which include 2-aminoanisole-3-sulfonic acid and 2
-Aminoanisole-4-sulfonic acid, 2-aminoanisole-5-sulfonic acid, 2-aminoanisole-6-
Sulfonic acid, 3-aminoanisole-2-sulfonic acid,
3-aminoanisole-4-sulfonic acid, 3-aminoanisole-5-sulfonic acid, 3-aminoanisole-6
-Sulfonic acid, 4-aminoanisole-2-sulfonic acid, 4-aminoanisole-3-sulfonic acid and the like can be mentioned. The methoxy group of anisole is an ethoxy group,
It is also possible to use a compound substituted with an alkoxy group such as an iso-propoxy group. However, 2-aminoanisole-3-sulfonic acid, 2-aminoanisole-4
-Sulfonic acid, 2-aminoanisole-5-sulfonic acid, 2-aminoanisole-6-sulfonic acid, 3-aminoanisole-2-sulfonic acid, 3-aminoanisole-4-sulfonic acid, 3-aminoanisole-6 -Sulfonic acid is preferably used. A sulfonated polyaniline copolymer obtained by further sulfonating a copolymer of at least one compound selected from the group consisting of aniline, the aniline derivative and the phenylenediamines and the aminobenzenesulfonic acid with a sulfonating agent is It is used as one component of the conductive composition of the present invention.

As described above, the sulfonated polyaniline copolymer used in the present invention contains sulfonic acid groups in the aromatic ring in an amount of 10% or more, preferably 20% or more, more preferably 40% or more. There is no problem for the purpose of the present invention even if an aromatic ring containing an acid group and an aromatic ring not containing an acid group are mixed or arranged alternately. When the sulfonic acid group content of the sulfonated polyaniline copolymer is less than 10%, the solubility or dispersibility of the copolymer in water, alcohol or a mixed solvent system thereof becomes insufficient, resulting in a substrate. The coating property and spreadability on the film are deteriorated, and the conductivity of the obtained coating film tends to be remarkably lowered. The molecular weight of the sulfonated polyaniline copolymer used in the present invention is 300-
It is 500000, and a molecular weight of 1000 or more is preferable in terms of solubility in the solvent and strength of the coating film.

The proportion of the sulfonated polyaniline copolymer used is 0.1 to 20 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the solvent. As the solvent, any organic solvent can be used as long as it does not dissolve or swell a substrate such as a polyester film,
It is preferable not only to use a mixed solvent of water and / or an organic solvent such as alcohol from the viewpoint of the use environment, but also the coating property to the structure forming body and the conductivity may be improved.

Organic solvents include alcohols such as methanol, ethanol, propanol and isopropyl alcohol,
Acetone, ketones such as methyl ethyl ketone and methyl isobutyl ketone, cellosolves such as methyl cellosolve and ethyl cellosolve, propylene glycols such as methyl propylene glycol and ethyl propylene glycol, amides such as dimethylformamide and dimethylacetamide, N-methylpyrrolidone, Pyrrolidones such as N-ethylpyrrolidone are preferably used. These are used by mixing with water at an arbitrary ratio. Specific examples of this are water / methanol, water / ethanol,
Water / propanol, water / isopropanol, water / methyl propylene glycol, water / ethyl propylene glycol and the like can be mentioned. The ratio used is preferably water / organic solvent = 1/10 to 10/1.

The conductive composition of the present invention can form a coat layer having good coatability, spreadability and surface strength with only the above components, but it does not contain a polymer compound and / or a surfactant soluble in a solvent. Further, when used in combination, it is possible to coat a substrate having poor wettability. Examples of polymer compounds suitable for this purpose include, for example, polyacrylamide, water-soluble resins such as polyvinylpyrrolidone, water-soluble or water-dispersible copolyesters containing a hydroxyl group or a carboxylic acid group,
Acrylic acid resins such as polyacrylic acid and polymethacrylic acid, acrylic acid ester resins such as polyacrylic acid ester and polymethacrylic acid ester, ester resins such as polyethylene terephthalate and polybutylene terephthalate, polystyrene, poly-α-methylstyrene, poly Styrene resins such as chloromethylstyrene, polystyrene sulfonic acid and polyvinylphenol, vinyl ether resins such as polyvinyl methyl ether and polyvinyl ethyl ether, polyvinyl alcohols such as polyvinyl alcohol, polyvinyl formal and polyvinyl butyral, and phenolic resins such as novolak and resole. Used. Among them, a water-soluble or water-dispersible copolymerized polyester containing a hydroxyl group or a carboxylic acid group is preferable from the viewpoint of compatibility with the sulfonic acid group-containing polyaniline of the present invention and from the viewpoint of adhesiveness to a support such as polyester. .

For the purpose of improving the wettability to the conductive composition of the present invention, surfactants such as anionic surfactants such as alkyl sulfonic acid, alkylbenzene sulfonic acid and alkyl carboxylic acid, alkyl amine and aryl 4 are used.
Cationic surfactants such as primary amines, amphoteric surfactants such as carboxybendine and aminocarboxylic acid, nonionic surfactants such as polyexethylene ethylene alkyl ether polyoxyethylene sorbitan fatty acid ester, and fluoroalkylcarboxylic acid, Fluoroalkylcarboxylic acid, perfluoroalkylbenzenesulfonic acid,
Fluorine-based surfactants such as perfluoroalkyl quaternary ammonium and perfluoroalkyl polyoxyethylene ethanol are used. From the viewpoint of improving the wettability to a polyester substrate, a fluorochemical surfactant is preferable.

Examples of the coating method include a gravure roll coating method, a reverse roll coating method, a knife coater method, a dip coating method and a spin coating method, but the coating method suitable for the conductive composition is not particularly limited.
There are an in-line coating method in which application to a film is performed simultaneously in a film-forming step and an offline coating method in which coating is independently performed after the production of a film-forming roll. The sulfonated polyaniline of the present invention is unstable at a high temperature of 250 ° C. or higher,
Since the thermal stability is good for about 3 minutes at 0 ° C., heating for a short time at 200 ° C. does not adversely affect the conductivity, although it depends on the types of coexisting polymer compounds and additives. Rather, from the viewpoint of improving the conductivity of the coated surface, it is preferable to heat at around 200 ° C. for 30 seconds or less.

In the present invention, the surface resistance value of the conductive layer is 10 ⁹ to 10 ¹⁴ Ω / at a humidity of at least 15 to 95% RH.
It must be □. If the surface resistance value is less than 10 ⁹ Ω / □, the image density is low, and if it exceeds 10 ¹⁴ Ω / □, toner jump occurs. Further, in order to impart transportability, antistatic property, etc. to the support, it is possible to apply a matte coat, an antistatic agent or the like on the surface opposite to the image receiving layer.

The thickness of each layer laminated by such a method is not particularly limited, but as a support,
The thickness is preferably 200 μm, the conductive layer is 0.1 to 10 μm, and the image receiving layer is 3 to 20 μm.

An image can be formed on the image-receiving layer of the electrophotographic direct-writing type recording medium manufactured as described above by a laser printer utilizing indirect electrophotography.

The electrophotographic direct-writing type recording medium of the present invention uses a conductive composition containing a specific sulfonated polyaniline as a conductive layer so that toner does not fly and is clear even at low humidity and high humidity. An image printed matter can be obtained, a complicated dispersing step is unnecessary, and in-line coating is possible, which is effective in simplifying the manufacturing process and reducing the cost.

[0021]

EXAMPLES Examples and comparative examples of the present invention will be described below, but the present invention is not limited to these examples. The evaluation method used in the present invention is shown below.

1) Surface resistance value The surface resistance value was measured at three conditions of 25, 50 and 95% RH.

2) Toner flying A recording medium produced by using a laser printer TN-7270.PS1 manufactured by "TOSHIBA CORPORATION" after leaving it for 24 hours under three conditions of 15, 50 and 95% RH at 25.degree. The periphery of the image area (image area) was observed by enlarging it 10 times, and the presence or absence of toner adhesion was evaluated. ：: Little toner jump is observed. Δ: Toner skipping is partially observed. X: Toner flying is clearly observed.

3) Image Density A recording medium produced by using a laser printer TN-7270.PS1 manufactured by "TOSHIBA CORPORATION" after leaving it for 24 hours under three conditions of 15, 50 and 95% RH at 25.degree. The image area of No. 2 was magnified 10 times, and the blurring, color strength, and the like were evaluated. ：: The image is clearly observed without blurring. Δ: There is no blur, but the image density is slightly low. X: Blurring is observed and the image density is low.

4) Contamination of printed matter When used as a lithographic printing plate, at 25 ° C. for 15.5%.
A laser printer TN-7270 manufactured by "TOSHIBA CORPORATION" was left for 24 hours under three conditions of 0.95% RH.
As an evaluation of the printability of the planographic printing plate output using PS1, the image of the output recording medium was printed on paper using an offset printing machine of "Ricoh Co., Ltd." evaluated. ：: Almost no stain is observed around the image portion (image portion) of the printed matter. Δ: Stain is observed on a part of the periphery of the image portion (image portion) of the printed matter. ×: Smear is observed around the entire image area (image area) of the printed matter.

Synthesis Example 1 Preparation of Sulfonic Acid Group-Containing Polyester and Its Aqueous Dispersion Liquid First, a sulfonic acid group-containing polyester was synthesized by the following method, and its dispersion liquid was prepared. Dimethyl terephthalate 49 mol%, dimethyl isophthalate 49 mol% and sodium 5-sulfoisophthalate 2 mol% were used as dicarboxylic acid components, and ethylene glycol 50 mol% and neopentyl glycol 5 as glycol components.
Using 0 mol%, a transesterification reaction and a polycondensation reaction were carried out by a conventional method. The glass transition temperature of the obtained sulfonic acid group-containing polyester was 69 ° C. 300 parts of this sulfonic acid group-containing polyester and 150 parts of n-butyl cellosolve are heated and stirred to form a viscous solution, and 550 parts of water is gradually added to the solution with stirring to give a uniform pale white solid content of 30% by weight. An aqueous dispersion of was obtained. This dispersion is
Further, the mixture was added to an equal volume mixture of water and isopropanol to prepare a sulfonic acid group-containing polyester aqueous dispersion having a solid content of 8% by weight.

Synthesis Example 2 Preparation of Polyaniline Coating Solution Containing Sulfonic Acid Group 10 parts by weight of phenylenediamine and 19 parts by weight of p-aminobenzenesulfonic acid were added dropwise to a hydrochloric acid solution of ammonium sulfate under acidic conditions of hydrochloric acid. After completion of dropping, the reaction product was stirred for a predetermined time, washed by filtration, and dried to obtain a powdery copolymer. This copolymer was added to 1000 parts by weight of concentrated sulfuric acid, and stirred at a predetermined temperature for 6 hours for sulfonation.
The reaction product was dropped into an ethanol solution, and the obtained precipitate was separated by filtration, washed and dried to obtain a sulfonated polyaniline.
This compound was found to have a sulfonic acid group absorption at around 1100 cm ^-1 in the IR spectrum. At this time, the content of sulfone groups in the sulfonated polyaniline was 50%. 2.0 parts by weight of the sulfonated polyaniline and 1.2 parts by weight of trimethylamine were dissolved in 50 parts by weight of water and 50 parts by weight of isopropanol. A liquid obtained by mixing this liquid with 100 parts by weight of the dispersion liquid shown in Synthesis Example 1 was used as the conductive composition of the present invention. This coating solution was dark green and no insoluble matter was observed in appearance.

Example 1 The liquid prepared in Synthesis Examples 1 and 2 was applied onto a 100 μm thick white polyester film containing cavities to form a conductive intermediate layer. On top of this, CaCO ₃ (particle size 0.
8 μm) 53 parts, polystyrene particles (particle size 6 μm) 1
Dispersion of 2 parts and 35 parts of water-soluble copolyester dispersed in a ball mill for 2 hours, water-soluble copolyester, urethane resin (Daiichi Kogyo Seiyaku Co., Ltd .: Elastron H-
3), an antistatic agent (manufactured by Nippon Synthetic Chemical Industry Co., Ltd .: Gocefimer), and water 30 / 10.5 / 25, respectively.
The coating liquid mixed at a ratio of /7.5/27 was coated with a wire bar (# 10) and dried at 160 ° C for 1 minute to provide an image receiving layer having a solid content thickness of 9 µm. Next, an arbitrary image was output on the image receiving layer of this laminated film using a laser printer TN-7270.PS1 manufactured by "Toshiba Corporation".

Example 2 Instead of the image receiving layer of Example 1, zinc oxide (manufactured by Sakai Chemical Co., Ltd .: SAZEX # 2000, average particle size 0.4 μm) was used.
m) 62.5 parts, acrylic resin (Dainippon Ink Co., Ltd.)
Made by: Acridic 44-179) 5 parts, toluene 3
A dispersion obtained by dispersing 2.5 parts by a ball mill for 2 hours, an acrylic resin (manufactured by Dainippon Ink and Chemicals: Acridic 44-
179), acrylic resin (manufactured by Mitsubishi Rayon Co., Ltd .: Dianal LR-333), silica (manufactured by Degussa): HK1.
25, secondary particle diameter 4 μm), toluene, and cyclohexanone 38 / 0.6 / 5.95 / 1.15 /
The coating solution mixed at a ratio of 36.0 / 18.30 was coated with a wire bar (# 10) and dried at 160 ° C. for 1 minute to provide an image receiving layer having a solid content of 7 μm. Then, on the image receiving layer of this laminated film, an arbitrary image is displayed
Output was performed using a laser printer TN-7270.PS1 manufactured by "Toshiba". When used as a planographic printing plate, the surface of the image receiving layer is an etchant (manufactured by Niken Chemical Co., Ltd .:
After processing with PP clean H), TE manufactured by Shinano Kenshi
An XELAR01 type offset printing machine was used to actually print 10,000 sheets of coated paper.

Example 3 Preparation was carried out in the same manner as in Example 2 except that the liquids prepared in Synthesis Examples 1 and 2 were further dispersed in a ball mill for 1 hour and then applied to form a conductive intermediate layer. And then
evaluated.

Example 4 Preparation was carried out in the same manner as in Example 2 except that an aqueous solution of polyvinyl alcohol (Poval) was used in place of the sulfonic acid group-containing polyester of Synthesis Example 1 and the aqueous dispersion. Done and evaluated.

Comparative Example 1 In Example 2, whiskers of potassium titanate (Otsuka Chemical Co., Ltd.) were used instead of the liquids prepared in Synthesis Examples 1 and 2.
Manufactured by TISTAT-PHS), a copolyester resin (manufactured by Toyobo Co., Ltd .: MD16), water, and isopropyl alcohol mixed at a ratio of 30/30/32/8 with a wire bar (# 10). Apply, 16
Preparation and evaluation were performed in the same manner as in Example 2 except that the conductive intermediate layer having a solid content of 2 μm was formed by drying at 0 ° C. for 1 minute.

Comparative Example 2 Instead of the liquids prepared in Synthesis Examples 1 and 2 in Example 2, whiskers of potassium titanate (Otsuka Chemical Co., Ltd.) were used.
Co., Ltd., TISTAT-PHS), copolyester resin (manufactured by Toyobo Co., Ltd .: MD16), water, and isopropyl alcohol were mixed at a ratio of 30/30/32/8, and further dispersed by a ball mill for 1 hour. Was applied with a wire bar (# 10) and dried at 160 ° C. for 1 minute to form and evaluate a conductive intermediate layer having a solid content of 2 μm in the same manner as in Example 2.

Comparative Example 3 A sample was prepared in the same manner as in Example 2 except that an anionic polymer solution was applied in place of the solution prepared in Synthesis Examples 1 and 2 in Example 2 to form a conductive intermediate layer. Done and evaluated.

Table 1 shows the evaluation results of Examples 1 to 4 and Comparative Examples 1 to 3.

[Table 1]

As can be seen from Table 1, the electrophotographic direct drawing type recording medium and the electrophotographic direct drawing type lithographic printing plate of the examples are
In spite of any humidity, none of the toners flew, the image density was high, and good printed matter was obtained.
On the other hand, Comparative Example 1 is excellent in each evaluation as in the case of Example, but when the conductive intermediate layer coating liquid is dispersed as in Comparative Example 2, the surface resistance becomes large, toner scatters, and a clear image is obtained. I couldn't get it. That is, it was difficult to control the conductivity when an inorganic conductive agent was used. Further, in Comparative Example 3, the surface resistance becomes large at low humidity and toner scattering occurs, and at high humidity, on the contrary, the surface resistance becomes small and the image density becomes thin, and clear images and printed matter can be obtained in both cases. could not.

[0037]

As is apparent from the above description, the electrophotographic direct-writing type recording medium and the electrophotographic direct-writing type lithographic printing plate according to the present invention are more excellent than those in which a conductive layer is formed by another composition. Since there is almost no humidity dependency and there is almost no change in the surface resistance value due to dispersion conditions or the like, it is easy to control the conductivity. As described above, since the toner does not fly and the image density is high and a clear image and a printed matter can be obtained, it is extremely useful as an electrophotographic direct writing type recording medium and an electrophotographic direct writing type planographic printing plate.

Claims (7)

[Claims] 1. In an electrophotographic direct-writing type recording medium in which an image receiving layer is provided on one surface of a support through a conductive layer, the amount of sulfonic acid groups bonded to the aromatic ring in the conductive layer is the aromatic ring. To 10 ⁹ to 10 ¹⁴ Ω at a humidity of a conductive layer containing a sulfonated polyaniline in an amount of 10% or more, and the surface resistance value of the conductive layer is 15 to 95% RH.
An electrophotographic direct-writing type recording medium characterized by being / □. 2. An aniline obtained by sulfonation of a copolymer mainly composed of an aminobenzene sulfonic acid compound and at least one compound selected from the group consisting of aniline, aniline derivatives and phenylenediamines. The electrophotographic direct-writing type recording medium according to claim 1, which is a sulfonated copolymer. 3. An aniline-based copolymer obtained by copolymerizing sulfonated polyaniline with at least one compound selected from the group consisting of aniline, aniline derivatives and phenylenediamines and an alkoxy group-substituted aminobenzene sulfonic acid compound. The electrophotographic direct-writing type recording medium according to claim 1, which is a combined sulfonate. 4. The support is a void-containing polyester film obtained by at least uniaxially stretching a sheet-like material obtained by mixing polyester and a thermoplastic resin incompatible with the polyester. The electrophotographic direct-writing type recording medium according to any one of claims 1 to 3. 5. The image receiving layer has an average particle size of 0.2 to 0.9.
5. Including ZnO particles of μm.
An electrophotographic direct-writing type recording medium according to any one of 1. 6. The number of projections and depressions on the surface of the image receiving layer having a height from the center line of 2 μm is 200 to 1000 / mm ^2.
And the number of protrusions with a height of 6 μm from the center line is 4
It is 0-400 pieces / mm ² , It is characterized by the above-mentioned.
<5> The electrophotographic direct-writing type recording medium according to any one of <5> to <5>. 7. An electron forming an image on the image receiving layer of the electrophotographic direct drawing type recording medium according to claim 1 by a laser printer utilizing indirect electrophotography. Image forming method for photographic direct writing type recording medium.