JP2832023B2 - Charge holding medium having protective film - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charge storage medium capable of recording information electrostatically by an exposure method at the time of applying a voltage and reproducing the information at any time. The present invention relates to a charge holding medium having excellent charge holding characteristics.

[Conventional technology]

Conventionally, silver halide photography has been known as a high-sensitivity photographing technique. In this photographic method, a photographed image goes through a development process,
When reproducing an image recorded on a film or the like as a recording medium, a silver salt emulsion (such as photographic paper) is used, or a developed film is optically scanned and reproduced on a cathode ray tube (CRT). ing.

In addition, an electrode is deposited on the photoconductive layer, the entire surface of the photoconductive layer is charged by corona charging on the photoconductive layer in a dark place, and then exposed to strong light to make the photoconductive layer exposed to light conductive. By leaking and removing the charge, an electrostatic latent image is optically formed on the surface of the photoconductive layer, and a toner having a charge of the opposite polarity (or charge of the same polarity) as the residual electrostatic charge is attached. There is an electrophotographic technique of electrostatically transferring and developing on paper, etc., but this is mainly used for copying, and generally cannot be used for photographing due to low sensitivity, and in a photoconductive layer as a recording medium Usually, toner development is performed immediately after the formation of an electrostatic latent image due to a short electrostatic charge retention time.

[Problems to be solved by the invention]

Silver halide photography is excellent as a means of preserving the subject image, but requires a development step to form a silver halide image,
Image reproduction requires complicated optical, electrical, or chemical treatments such as hard copy and soft copy (CRT output).

In electrophotographic technology, visualization of the obtained electrostatic latent image is easier and faster than silver halide photography, but the latent image storage is extremely short,
The dissociation property and image quality of the developer are inferior to silver salts.

In the TV shooting technique, line-sequential scanning is required to extract and record an electric image signal obtained by an image pickup tube. Line-sequential scanning is performed by an electron beam in an image pickup tube, and a magnetic head is used in video recording. However, since the resolution depends on the number of scanning lines, the resolution is significantly deteriorated as compared with a planar analog recording such as a silver halide photograph.

A TV imaging system using a solid-state imaging device (CCD or the like), which has recently been developed, has essentially the same resolution.

The problems with these technologies are that image recording is of high quality,
If the resolution is high, the processing steps are complicated, and if the steps are simple, there is a lack of a storage function or a basic deterioration of image quality.

The present invention is to solve the above problems, high quality, high resolution, a simple processing process, long-term storage is possible, stored characters, line drawings, images, codes,
(1.0) It is an object of the present invention to improve the charge holding characteristics of a charge holding medium capable of arbitrarily and repeatedly reproducing information with a desired image quality.

[Means for solving the problem]

Therefore, the charge-holding medium of the present invention is composed of a polymer material having a specific resistance of 10 ¹⁴ Ωcm or more and a glass transition temperature of not less than the use environment temperature on the electrode layer, and having a thickness of 0.1 μm or more. In the charge holding medium having the holding layer laminated thereon, the charge holding characteristic is improved by stacking a protective film on the charge holding layer, and particularly, the protective film is an insulating plastic film or an insulating film. It is characterized by being formed by coating a plastic solution or further by melt-transferring insulating molten plastic.

 Hereinafter, the charge holding medium of the present invention will be described.

FIG. 1 is a view for explaining each aspect of the charge holding medium of the present invention by a sectional view or a perspective view. FIG. 1 (a) shows an embodiment, and FIG. FIG. 1 (c) is a perspective view of another embodiment shown in FIG. 1 (b), wherein 2 is a spacer, 3 is a charge holding medium, 11 is a charge holding layer, and 13 is A charge holding medium electrode, 15 is a charge holding layer support, and 20 is a protective film.

The charge holding layer 11 is made of a high-insulating polymer material to suppress the transfer of charges, and is required to have an insulating property of a specific resistance of 10 ¹⁴ Ω · cm or more. In addition, the polymer material constituting the charge retaining layer must have a glass transition temperature equal to or higher than the use environment temperature.

As such a polymer material, a thermoplastic resin, a thermosetting resin, an ultraviolet curable resin, an energy beam curable resin such as an electron beam curable resin, or an engineering plastic can be used.

As the thermoplastic resin, for example, polyethylene, vinyl chloride resin, polypropylene, styrene resin, ABS resin,
Polyvinyl alcohol, acrylic resin, acrylonitrile-styrene resin, vinylidene chloride resin, AAS (ASA)
Resin, AES resin, cellulose derivative resin, thermoplastic polyurethane, polyvinyl butyral, poly-4-methylpentene-1, polybutene-1, rosin ester resin and the like, and furthermore a fluorine resin such as polytetrafluoroethylene, fluorinated ethylene propylene, Tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers, their dispersion type or modified type (coating type), polyether ether ketone resin,
Polyparaxylylene represented by the following structural formula, (Note that the C type is not only the one having the above structure, but also one in which a portion of the benzene ring other than the main chain binding site is substituted with chlorine, and the D type is one in which two of them are substituted with chlorine. The thermosetting resin includes, for example, unsaturated polyester resin, epoxy resin, phenol resin, urea resin, and the like.
Melamine resins, diallyl phthalate resins, silicone resins, and the like, and further, as an ultraviolet ray-curable resin, an energy ray-curable resin such as an electron beam-curable resin, there are radically polymerizable acrylate compounds, for example, acrylic acid or methacrylic acid or these. An ester compound of a derivative having hydroxyl groups at both ends, specifically, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, (Meth) having one polymerizable unsaturated group such as 4-hydroxycyclohexyl acrylate, 5-hydroxycyclooctyl acrylate, and 2-hydroxy-3-phenyloxypropyl acrylate Starting with acrylate compounds, the formula The compound etc. which have two polymerizable unsaturated groups shown by these can be used.

Examples of the curable compound having two hydroxyl groups and one or more radically polymerizable unsaturated groups include, for example, glycerol methacrylate and the following general formula: (Where R and R 'are methyl groups or hydrogen, and R ₁ is a short-chain diol residue such as ethylene glycol, propylene glycol, diethylene glycol, butanediol, 1.6-hexanediol). Can be used.

As the engineering plastic, polycarbonate, polyamide, acetal resin, polyphenylene oxide, polybutylene terephthalate, polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polyimide resin, polysulfone, aromatic polyester, polyacrylate and the like can be used.

As a method of laminating the charge holding layer, first, in the case of the charge holding medium shown in FIG. 1 (a), coating and dipping are performed by depositing a resin or rubber on the electrode by vapor deposition, sputtering, or dissolving in a solvent. Thus, a layer can be formed.

Further, as the charge holding layer 11, a monomolecular film formed by a Langmuir-Blodget method or a monomolecular accumulation film can also be used.

Further, as the charge retention layer 11, a silicone film, a polyester film, a polyimide film, a fluorine-containing polymer film, a polyethylene film, a polypropylene film, a polyparabenic acid film, a polycarbonate film, a polyamide film, or the like is adhered via an adhesive or the like. A layer may be formed.

Alternatively, an electrode may be formed on one side of the film by vapor deposition, sputtering, coating, or the like. Further, a layer for protecting the electrode may be provided thereon, and if further mechanical strength is required, the layer may be bonded to a film having higher mechanical strength.

In addition, photoconductive or conductive fine particles may be present in the insulating polymer material for charge lamination.

Amorphous silicon as photoconductive fine particle material,
An inorganic photoconductive material such as crystalline silicon, amorphous selenium, crystalline selenium, cadmium sulfide, and zinc oxide, and an organic photoconductive material such as polyvinyl carbazole, phthalocyanine, and azo pigment are used.

Examples of the conductive material include Group IA (alkali metal), Group IB (copper), Group IIA (alkaline earth metal), Group IIB (zinc group), and Group IIIA of the periodic table. (Aluminum group), IIIB group (rare earth), IVB group (titanium group),
VB (Vanadium), VIB (Chrome), V
Group B (manganese group), group VIII (iron group, platinum group), or group IV A (carbon group) are carbon, silicon, germanium, tin, lead, and group VA (nitrogen group) are antimony. , Bismuth, and VIA (oxygen group) include sulfur, selenium, and tellurium in fine powder form. Metals among the above elemental elements can be used in the form of metal ions, fine powdery alloys, organic metals, and complexes. Further, the above element simple substance can be used in the form of an oxide, a phosphate, a sulfate, or a halide. Especially carbon, gold, copper,
Aluminum or the like is preferably used.

The fine particle layer is formed by vapor-depositing the material on the electrode or the charge retention layer using a low-pressure vapor deposition device. The material for forming the particle layer aggregates when evaporated under a low pressure of about 10 Torr to 10 ^-3 Torr, becomes a state of ultrafine particles having a diameter of about 10 to 0.1 μm, and is laminated on the surface of the electrode or the charge retention layer. When the charge holding layer is formed by coating, the fine particle material may be dispersed in a charge holding layer forming material solution and coated on the charge holding layer.

Further, the charge holding layer 11 may be provided with a charge holding enhancement layer between the electrode surface and the charge holding layer 11. The charge retention enhancing layer refers to a layer into which electric charge is injected when a strong electric field (10 ⁴ V / cm or more) is applied, but which is not injected at a low electric field (10 ⁴ V / cm or less). As the charge retention enhancing layer, for example, SiO ₂ , Al ₂ O ₃ , SiC, SiN, etc. can be used, and as the organic substance, for example, a polyethylene vapor-deposited film,
A polyparaxylene deposited film can be used.

In order to more stably hold an electrostatic charge, a substance having an electron donating property (donor material) or a substance having an electron accepting property (acceptor material) may be added to the charge retaining layer 11. Donor materials include styrene, pyrene, naphthalene, anthracene, pyridine, and azine compounds, and specifically, tetrathiofulvalene (TTF), polyvinylpyridine, polyvinylnaphthalene, polyvinylanthracene, polyazine, and polyvinylpyrene. , Polystyrene and the like are used, and one kind or a mixture is used. As the acceptor material, there are a halogen compound, a cyan compound, a nitro compound and the like, and specifically, tetracyanoquinodimethane (TCNQ) trinitrofluorenone (TNF) and the like are used, and one kind or a mixture is used. The donor material and the acceptor material are used by adding about 0.001 to 10% to the resin or the like.

The charge retention layer 11 has a thickness of at least 1000 mm from an insulating point.
(0.1 μm) or more, and preferably 100 μm or less from the viewpoint of flexibility.

The charge retention medium of the present invention is characterized in that after information recording, a protective film is laminated on the surface of the charge retention medium in order to prevent damage to the surface of the charge retention medium and attenuation of information charges.

As the protective film, first, a reclaimed rubber, styrene-butadiene rubber, polyisoprene, butyl rubber, Bunner N (butadiene acrylonitrile rubber), polyvinyl ether (ethyl group, or Having the above hydrocarbon group as an alcohol residue), polyacrylate ester (having an ethyl group or a higher hydrocarbon group), silicone rubber, polyterpene resin, gum rosin, rosin ester, and rosin derivative, oil-soluble A phenolic resin, a coumarone-indene resin, or a mixture of two or more of petroleum hydrocarbon resins is formed into a film having a thickness of several hundreds of m to several tens of μm, and is adhered to the surface of the charge holding medium. Use an adhesive that can peel the insulating plastic film. May be adhered to, as the adhesion agent specific resistance 10 ¹⁴ Ω · cm or more silicone oil, dimethyl silicone oil, methylphenyl silicone oil, higher fatty acid modified silicone oil, methyl chlorinated phenyl silicone oil, alkyl-modified silicone Oil, methyl hydrogen silicone oil, cyclic polydimethylsiloxane, silicone polyether copolymer, amino-modified silicone oil, epoxy-modified silicone oil, insulating oil and the like may be used alone or in combination of two or more.

Further, an insulating plastic film may be laminated on the charge holding layer using an adhesive.

Alternatively, the insulating plastic may be dissolved in a solvent and applied by a vapor deposition method, a spinner coating method, or the like so as to have a film thickness of several hundreds to several tens μm when dried.

As the melt transfer material, EVA (ethylene-vinyl acetate copolymer), EEA (ethylene-ethylene acrylate copolymer), polyamide resin, rosin resin, hydrogenated petroleum resin, pinene resin, hydrocarbon resin, Synthetic rosin-based resins, terpene-based resins, waxes, and the like can be used. If necessary, two or more of the above materials may be mixed, or an inorganic powder may be added. Further, a material capable of melting and transferring the protective layer at a temperature at which the charge on the charge retaining layer does not attenuate by heating is preferable.

Information can be read from the protective film, and the thickness of the protective film is preferably thin in order to improve the reading resolution. This is because in order to read with high resolution, it is better to move the reading sensor closer to the portion where the electric charge is stored. If the reading resolution is not a problem, the protective film may be thick.

If the protective film is of the above-mentioned adhesive type, the information on the surface of the charge holding layer may be reproduced by peeling the protective film.

Further, as shown in FIG.
20 may be laminated. In this case, a plastic film is used as a protective film, and a spacer 2 is
It is good to laminate through. The distance between the charge retaining layer and the protective film is suitably 1 to 50 μm, and the spacer 2 is preferably made of an organic material such as plastic. In this case, in order to reproduce recorded information, the protective film 20 needs to be replaced with the charge retaining layer 11. The spacer 2 and the charge holding layer 11 need to be peelably bonded to each other, and the spacer 2 and the charge holding layer 11 need to be separated from each other. It is good to let.

The charge holding medium electrode 13 is formed on the charge holding layer support except when a metal material is used for the charge holding layer support, and the material thereof has a specific resistance of 10 ⁶ Ωcm or less. The conductive film is not limited, and is an organic conductive film such as a metal conductive film, an inorganic metal oxide conductive film, and a quaternary ammonium salt. Such a charge retention layer electrode is deposited on its support by vapor deposition, sputtering, CVD, or the like.
It is formed by a method, coating, plating, dipping, electrolytic polymerization or the like. The thickness of the electrode must be changed depending on the electric characteristics of the material constituting the charge storage layer electrode and the voltage applied when recording information. For example, in the case of aluminum, the thickness is about 100 to 3000 mm. When it is necessary to input the information light, the charge holding layer electrode is required to have the same optical characteristics as the support. For example, the information light is a visible light (400 to 700 nm).
If it is, ITO (In ₂ O ₃ -SnO ₂ ), or a transparent electrode such as tin oxide or the like, which is sputtered or deposited, or these fine powders are ink-coated with a binder and coated, gold, aluminum, silver A translucent electrode prepared by vapor deposition or sputtering of nickel, chromium, or the like, an organic transparent electrode coated with a coating of tetracyanoquinodimethane (TCNQ), polyacetylene, or the like is used.

The above-mentioned electrode material can also be used when the information light is infrared light (700 nm or more). In some cases, a visible light absorbing electrode colored to cut off visible light can also be used.

Further, when the information light is ultraviolet light (400 nm or less), the above-mentioned electrode material can be used. However, organic polymer materials that absorb ultraviolet light, soda glass, and the like are not preferable, and ultraviolet light such as quartz glass is transmitted. It is good to use the material which does.

The charge holding layer support 15 strongly supports the charge holding layer, but the light transmittance may be required similarly. Specifically, when the charge holding medium 3 takes the shape of a flexible film, tape, or disk, a flexible plastic film is used, and when strength is required, a rigid sheet, glass, or the like is used. An inorganic material or the like is used.

The charge holding medium 3 is used together with the photoreceptor 1 to record information as a static charge distribution on the surface of or inside the charge holding layer 11 constituting the charge holding medium 3. It is used as a recording medium. Therefore, the shape of the charge holding medium can take various shapes depending on the information to be recorded or the recording method. For example, an electrostatic camera (Japanese Patent Application No. 63
-121591), it will be in the form of a general film (for single frame or continuous frame) or disk shape. When recording digital or analog information by laser, etc., it will be in tape or disk shape. Or card shape.

Next, an electrostatic image recording method using the charge holding medium will be described with reference to FIG. In the figure, 1 is a photoconductor, 5
Is a photoconductive layer support, 7 is a photoreceptor electrode, 9 is a photoconductive layer, 17
Is the power supply.

FIG. 2 shows a mode in which exposure is performed from the photoconductor 1 side. First, a transparent photoconductor electrode 7 made of ITO having a thickness of 1000 mm is formed on a photoconductive layer support 5 made of glass having a thickness of 1 mm. The photoconductor 1 is formed by forming a photoconductive layer 9 of about 10 μm thereon. The charge holding medium 3 is arranged on the photoconductor 1 with a gap of about 10 μm. The charge holding medium 3 is obtained by depositing a 1000-mm thick Al electrode on a charge holding layer support 15 made of glass having a thickness of 1 mm, and forming a charge holding layer 11 having a thickness of 10 μm on this electrode.

First, as shown in FIG.
The charge holding medium 3 is set through a gap of about μm, and a voltage is applied between the electrodes 7 and 13 by the power supply 17 as shown in FIG. In a dark place, since the photoconductive layer 9 is a high-resistance body, no change occurs between the electrodes. When light is incident from the photoreceptor 1 side, the photoconductive layer 9 in the portion where the light is incident exhibits conductivity, a discharge is generated between the photoconductive layer 9 and the charge holding layer 11, and charges are accumulated in the charge holding layer 11.

After the exposure is completed, the voltage is turned off as shown in FIG.
F, and then, as shown in FIG.
, The formation of the electrostatic latent image is completed.

The photoconductor 1 and the charge holding medium 3 may be of a contact type instead of a non-contact type as described above. In the case of the contact type, a positive or negative charge is applied to the exposed portion of the photoconductive layer 9 from the photoconductor electrode 7 side. The electric charge is injected, the electric charge is drawn by the electrode 13 on the charge holding medium 3 side, passes through the photoconductive layer 9, stops the charge transfer when it reaches the surface of the charge holding layer 11, and the injected charge is transferred to the site. Stored.
When the photoconductor 1 and the charge holding medium 3 are separated from each other, the charge holding layer 11 is separated in a state where the charge is accumulated.
When this recording method is a planar analog recording, high resolution can be obtained as in the case of the silver halide photography.

The surface charges of the charge holding layer 11 in which the image is stored as information charges in this way are exposed to the air environment. However, in the present invention, the information charges are clarified by laminating an insulating protective film on this charge holding layer. It is stored for a long time without discharging regardless of location or dark place. The information charge may simply accumulate on the surface, and may microscopically penetrate into the vicinity of the insulator surface, causing electrons or holes to be trapped in the structure of the substance. Will be

As a method for inputting information to the charge holding medium of the present invention, there are a method using a high-resolution electrostatic camera and a recording method using a laser. First, the high-resolution electrostatic camera used in the present invention comprises a photoconductor 1 comprising a photoconductive layer 9 provided with a photoconductor electrode 7 on the front, instead of a photographic film used in a normal camera, A recording member is constituted by a charge holding medium comprising a charge holding layer 11 having a charge holding medium electrode 13 provided on the rear surface thereof, a voltage is applied to both electrodes, and the photoconductive layer becomes conductive according to incident light. The electrostatic latent image of the incident optical image is formed on the charge storage medium by accumulating electric charges on the charge holding layer in accordance with the amount of incident light, and a mechanical shutter can also be used. A shutter can also be used, and the electrostatic latent image can be held for a long time irrespective of a bright place or a dark place. In addition, a color filter that separates optical information into R, G, and B light components by a prism and takes out as parallel light is used, and one frame is formed with three sets of R, G, and B charge-retaining media, or By arranging the R, G, and B images on a plane to form one frame in one set, color photography can also be performed.

As a recording method using a laser, an argon laser (514.488 nm), a helium-neon laser (633 nm), a semiconductor laser (780 nm, 810 nm, etc.) are used as a light source.
A voltage is applied by bringing the photoreceptor and the charge holding medium into a planar shape and bringing the surfaces into close contact or facing each other at a certain interval. In this case, the photoconductor electrode may be set to the same polarity as the carrier of the photoconductor. In this state, laser exposure corresponding to the image signal, character signal, code signal, and line drawing signal is performed by scanning. Analog recording such as images is performed by modulating the laser light intensity, and digital recording such as characters, codes, and line drawings is performed by ON-OFF control of laser light. In the case where dots are formed in an image, the dots are formed by applying dot generator ON-OFF control to laser light. Note that the spectral characteristics of the photoconductive layer in the photoreceptor need not be panchromatic, but may be any as long as they have sensitivity to the wavelength of the laser light source.

Next, a method of reproducing the recorded electrostatic image will be described.

FIG. 3 is a diagram showing an example of a potential reading method in a method for reproducing an electrostatic image of a charge holding medium according to the present invention, and the same numbers as those in FIG. 1 indicate the same contents. In the drawing, 10 is a protective film, 21 is a potential reading section, 23 is a detection electrode, 25 is a guard electrode, 27 is a capacitor, and 29 is a voltmeter.

When the potential reading unit 21 is opposed to the charge storage surface of the charge holding medium 3 from above the protective film, an electric field generated by the charge stored on the charge holding layer 11 of the charge holding medium 3 acts on the detection electrode 23, and the detection is performed. An induced charge equal to the charge on the charge holding medium is generated on the electrode surface. Since the capacitor 27 is charged with the same amount of charge having the opposite polarity to the induced charge, a potential difference is generated between the electrodes of the capacitor according to the accumulated charge, and by reading this value with the voltmeter 29, the potential of the charge holder is reduced. You can ask. The electrostatic latent image can be output as an electric signal by scanning the surface of the charge holding medium with the potential reading unit 21. When the detection electrode 23 alone is used, an electric field (line of electric force) due to electric charges in a wider range than the detection electrode facing portion of the charge storage medium acts to lower the resolution. Therefore, the grounded guard electrode 25 is arranged around the detection electrode. You may do so. As a result, the lines of electric force are directed in the direction perpendicular to the surface, so that the lines of electric force only act on the portion facing the detection electrode 23, and the potential of the portion substantially equal to the detection electrode area is read. be able to. The accuracy and resolution of potential reading vary greatly depending on the shape and size of the detection electrode and guard electrode, and the distance between the detection electrode and the guard electrode. Therefore, it is necessary to design the optimum conditions in accordance with the required performance.

FIG. 4 is a diagram showing a schematic configuration of an electrostatic image reproducing method, in which 61 is a potential reading device, 63 is an amplifier, 65 is a CRT, 67
Is a printer.

In the figure, the electric potential can be detected by a potential reading device 61, the detected output can be amplified by an amplifier 63, displayed on a CRT 65, and printed out by a printer 67. In this case, at any time, a portion to be read can be arbitrarily selected and output, and repetitive reproduction can be performed.

In addition, optical reading can be performed using a material whose optical properties change due to an electric field, for example, an electro-optic crystal or the like.
Further, since the electrostatic latent image is obtained as an electric signal, it can be used for recording on another recording medium as needed.

[Action]

The charge holding medium is formed by laminating a charge holding layer on an electrode substrate, is opposed to the photoconductive layer surface on the photoreceptor electrode, and is exposed with a voltage applied between both electrodes,
In the photoconductive layer portion irradiated with the information light, the charge moves toward the electrode on the charge holding medium side, and the polarized charge is accumulated on the surface of the charge holding medium, or penetrates into the charge holding layer to maintain the durability. It serves as a certain charge holding medium.
However, the surface charge of the charge retaining layer is gradually attenuated by moisture in the air or the like. In addition, it may be destroyed by external damage. Therefore, the present invention can improve the charge retention characteristics by laminating the surface of the charge retention layer with an insulating film to protect the charge, thereby enabling the image information in the charge retention medium to be stored for a long period of time. is there.

When the protective layer is not provided, the charge is reduced or lost when the surface of the charge holding medium is physically contacted with a conductor, but when the protective layer is provided, there is physical contact of the conductor. Nor does the surface potential decrease. Further, even if an electrostatic charge is generated on the surface of the protective film due to friction or the like, it can be easily cleaned with a conductor such as water. When reproducing information, the protective film may be peeled off, and the information charges accumulated in the charge holding layer may be reproduced. Alternatively, the information may be reproduced from the protective film. The information thus accumulated can read and output the local potential of the electrostatic latent image at an arbitrary scanning density at an arbitrary time.

 Hereinafter, examples will be described.

[Example 1] (Preparation method of charge retention medium) To a mixed solution having a composition of 10 g of methylphenylsilicone resin and 10 g of xylene-butanol 1: 1 solvent, 1% by weight of a curing agent (metal catalyst): trade name CR-15 % (0.2 g) and stirred well, and coating was performed on a glass substrate on which Al was deposited at 1000 ° using a doctor blade 4 mil. Then 15
Drying was performed at 0 ° C. for 1 hour to obtain a charge holding medium having a thickness of 10 μm.

(Electrostatic Image Recording Method) As shown in FIG. 2, the organic photoreceptor (PVK-TNF) 1 manufactured in Reference Example 1 described later and the above-described charge holding medium were coated with a film thickness.
A 10-μm polyester film is used as a spacer and superposed so as to face each other. A DC voltage of −700 V is applied between the electrodes 7 and 13 with the photoconductor side negative and the charge holding layer side positive.

Next, under a voltage applied state, exposure was performed for 1 second using a halogen lamp having an illuminance of 1000 lux as a light source from the photoconductor side, and after completion of the exposure, the voltage was turned off. The photoconductive layer 9 in the portion where the light has entered shows conductivity, and discharge occurs between the photoconductive layer 9 and the charge holding layer 11, and the charges are accumulated in the charge holding layer 11. Next, by taking out the charge holding medium 3, the formation of the electrostatic latent image is completed.

(Method of forming protective film) 10 mg of dimethyl silicone oil (viscosity 10,000 cps, Toshiba Silicone Co., Ltd.) was dropped as a protective film on the surface of the charge retaining layer on which the electrostatic image was recorded, and a 20 μm polyester film was further laminated and laminated. And a polyester film was adhered to the surface of the charge retention layer.

(Charge Retention Characteristics) After recording the electrostatic image, a surface potential of -100 V was measured by a surface voltmeter on the charge retention layer in a state where the protective film was not laminated, while the surface potential was 0 V in an unexposed portion. However, as a result of measuring the surface potential from above the protective film, -100 V similar to the surface potential measurement result measured without laminating the protective film was obtained.

[Example 2] Silicon rubber (TSE326; Toshiba Silicon Co., Ltd.) was coated on a polyester film 20 µm with a doctor blade instead of silicone oil in the method of forming a protective film in the above example, and dried at 100 ° C for 1 hour. , 2μm
Was formed. This protective film was laminated on the surface of the charge holding layer of the charge holding medium on which the electrostatic image was recorded in Example 1. When its surface potential was measured, it had the same charge retention characteristics as when silicon oil was used.

Example 3 Al was vapor-deposited on a glass support having a thickness of 1 mm in a thickness of 1000 °, and then polyparaxylylene was formed as a charge retaining layer by vapor deposition to obtain a charge retaining medium.

Next, a solution obtained by dissolving a fluorine-containing resin (manufactured by Asahi Glass Co., Ltd.) in a fluorine-based solvent was coated on the surface of the charge holding layer on which the electrostatic charge was recorded by a spinner coating method.
A protective layer having a thickness of m was formed. As a result of measuring the surface potential from above the protective film, -100 V was obtained, which was the same as the surface potential measurement result measured without laminating the protective film.

Example 4 A 30% solution of stevelite ester 10 (manufactured by Rika Hercules) in monochlorobenzene on the surface of a 6 μm-thick polyester film (manufactured by Toray Industries, Inc.), one surface of which was subjected to a release treatment with a silicone-based release agent. Was applied by a roll coater to a dry thickness of 7 μm to prepare a film for melt transfer.

The charge holding medium was charged on the charge holding medium produced in the same manner as in Example 1 so that the surface potential became 100 V, and then combined with the above-mentioned film for fusion transfer, using a heat sealer and heated rolls heated to 60 ° C using a heat roll. It was produced by transferring a protective layer thereon.

As a result of measuring the surface potential from above the protective film, the same -100 V as the surface potential measurement result measured without laminating the protective film
Was obtained, and it was confirmed that a protective film could be formed by melt transfer.

Example 5 FIG. 5 is a diagram showing the change over time of the charge retention characteristics of the charge retention medium of Example 1.

In the figure, lines A and B show the case where the protective film was not laminated in Example 1 above, and line A was measured after leaving the device at a temperature of 25 ° C. and a humidity of 30%. Also, the surface charge on the charge holding medium hardly decayed. The B-line was measured by leaving it at a temperature of 40 ° C. and a humidity of 75%, but only about 25% attenuated after one week.

Example 6 FIG. 6 is a diagram showing the change over time of the charge retention characteristics of the charge retention medium of Example 3.

In the figure, ○ and □ indicate the charge retention characteristics of the case where the protective film was not laminated, × and Δ indicate the charge retention characteristics of the case where the protective film was laminated. □,
Δ is a value measured by standing at a temperature of 40 ° C. and a humidity of 95%.

As can be seen from this figure, the charge retention is significantly improved by laminating the protective film. That is,
X is a value measured by standing at room temperature and a humidity of 50%. Even when one month has passed, the surface charge on the charge-retention medium obtained by laminating a protective layer having a protective film (marked by x) is In contrast, no attenuation was observed as compared with the case where the protective layer was not laminated (marked with ○). □ and △ are measured at 40 ° C. and 95% humidity. Leakage was 45% for those without a protective film (marked with □) after about one month. In the case where the protective film was laminated (marked with △), the attenuation was only about 35%.

When the medium was not immersed in water, the charge completely disappeared when the protective film was not provided.However, when the medium was immersed in water, the electric potential could not be read from the protective film by immersion in water. When the potential of the medium surface was measured, the original potential was measured, and no change was observed in the resolution.

Reference Example 1 Organic Photoconductor (PVK-TNF) Preparation Method 10 g of poly-N-vinylcarbazole (Anan Kofu Co., Ltd.)
Manufactured), 2,4,7-trinitrofluorenone 10 g, polyester resin 2 g (binder: Byron 200 Toyobo Co., Ltd.)
A mixed solution having a composition of 90 g of tetrahydrofuran (THF) was prepared in a dark place, and a doctor blade was placed on a glass substrate (1 mm thick) in which In ₂ O ₃ —SnO ₂ was sputtered to a thickness of about 1000 mm. It was then applied and dried by ventilation at 60 ° C. for about 1 hour to obtain a photosensitive layer having a photoconductive layer having a thickness of about 10 μm. In order to dry completely, it was further dried naturally for one day before use.

〔The invention's effect〕

The present invention relates to a charge holding medium comprising an electrode layer and a charge holding layer having a high charge holding property.In the charge holding medium, a protective film is formed on the charge holding layer, and the surface of the charge holding layer is protected by laminating with an insulating film. It is intended to improve the holding characteristics and to store image information in the charge holding medium for a long period of time, and has the effect of not attenuating the surface potential even when a conductor is physically contacted. When reproducing information, the information charges accumulated can be reproduced with or without peeling off the protective film.

The image charges held in this way can read out and output the local potential of the electrostatic latent image at an arbitrary scanning density at an arbitrary scanning density. As a result, a high-quality original image and a record holding medium capable of outputting at an arbitrary time point can be obtained. In addition, by using the electrostatic charge recording and holding medium of the present invention, a physical and chemical means such as a developing means is not required for direct potential detection, so that an inexpensive and simple recording / reproducing system can be created. Can be done.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of the charge holding medium of the present invention, FIG. 2 is a view for explaining an electrostatic image recording method on the charge holding medium, and FIG. 3 shows an example of a DC amplification type potential reading method. FIG. 4 is a diagram showing a schematic configuration of the electrostatic image reproduction of the present invention.
FIG. 6 is a diagram showing the charge holding characteristics of the charge holding medium having the protective film manufactured in Example 1, and FIG. 6 is a diagram showing the charge holding characteristics of the charge holding medium having the protective film manufactured in Example 3. 1 is a photoreceptor, 2 is a spacer, 3 is a charge holding medium, 5 is a photoconductive layer support, 7 is a photoreceptor electrode, 9 is a photoconductive layer, 11 is a charge holding layer, 12 is a charge holding layer lacking portion, 13 Is a charge holding medium electrode, 15 is a charge holding layer support, 17 is a power supply, 20 is a protective layer,
21 is a potential reading unit, 23 is a detection electrode, 25 is a guard electrode,
27 is a capacitor.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Seiji Take, 1-1-1 Ichigaya-Kaga-cho, Shinjuku-ku, Tokyo Dai Nippon Printing Co., Ltd. (56) References JP-A-2-125264 (JP, A) ( 58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 5 / 02,5 / 147

Claims (4)

(57) [Claims] 1. The method according to claim 1, wherein the specific resistance is 10 ¹⁴ Ω · cm or more on the electrode layer.
In a charge holding medium comprising a polymer material having a glass transition temperature equal to or higher than the use environment temperature and a charge holding layer having a thickness of 0.1 μm or more, a charge holding layer is formed by stacking a protective film on the charge holding layer. A charge retaining medium having a protective film, wherein the charge retention medium is improved. 2. The charge retaining medium according to claim 1, wherein said protective film is an insulating plastic film. 3. The charge holding medium according to claim 1, wherein said protective film is formed by coating an insulating plastic solution. 4. The charge holding medium according to claim 1, wherein the protective film is formed by melt-transferring an insulating molten plastic.