JPH02203353A - Charge holding medium having protective film - Google Patents

Abstract

PURPOSE:To simplify a processing stage and allow arbitrary iterative reproduction of stored information with the image quality in accordance with purposes by laminating a protective film on a charge holding layer to improve charge holding characteristics. CONSTITUTION:The protective film 20 is formed on the charge holding layer 11 to laminate and protect the surface of the charge holding layer with an insulating film. The charge holding characteristics are, therefore, improved and the image information on the charge holding medium is preserved over a long period of time. The production of the accumulated information charge without peeling this protective film is possible at the time of reproducing the information. The image charge held in such a manner can be outputted by reading out the local potential of an electrostatic latent image at an arbitrary scanning density. The record holding medium which allows easy outputting of the original picture of high image quality at an arbitrary point of time is obtd. in this way.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a charge-retaining medium that can electrostatically record information using an exposure method when voltage is applied, etc., and that can reproduce information at any time. The present invention relates to a charge retention medium with excellent charge retention properties.

(Prior art) Silver halide photography is conventionally known as a high-sensitivity photographing technique.In this photography method, one most visible image is produced through a developing process.
Images are recorded on film, etc. as a recording medium, and are reproduced by using silver salt emulsion (photographic paper, etc.) or by optically scanning a developed film and reproducing it on a cathode ray tube (hereinafter referred to as CRT). ing.

In addition, electrodes are deposited on the photoconductive layer, the entire surface of the photoconductive layer is charged by corona charging in a dark place, and then exposed to strong light to make the photoconductive layer conductive in the areas exposed to the light. By leaking and removing the charge, an electrostatic latent image is optically formed on the surface of the photoconductive layer, and the toner having a charge opposite to that of the residual electrostatic charge (or a charge having the same polarity) is removed by the operator. In addition, there is an electrophotographic technology that involves electrostatic transfer and development, but this is mainly used for copying and cannot be used for photography due to its low sensitivity; Since the electrostatic charge retention time in the conductive layer is short, toner development is usually carried out immediately after the electrostatic latent image is formed.

[Problem to be solved by the invention]

Silver halide photography is an excellent means of preserving images of subjects, but it requires a developing process to form silver halide images, and image reproduction involves complex optical processes such as hard copy and soft copy (CRT output). physical, electrical, or chemical treatment is required.

In electrophotographic technology, visualization of the obtained electrostatic latent image is easier and faster than in silver salt photography, but the storage time of the latent image is extremely short, and developer release properties, image quality, etc. are inferior to silver salt.

TV photographing technology requires line-sequential scanning in order to extract and record electrical image signals obtained by an image pickup tube. Line-sequential scanning is performed using an electron beam in the image pickup tube and a magnetic head for video recording, but since resolution depends on the number of scanning lines, it is significantly degraded compared to planar analog recording such as silver halide photography.

Furthermore, TV imaging systems using solid-state imaging devices (CCDs, etc.), which have been developing in recent years, are essentially the same in terms of resolution.

Problems inherent in these technologies include a complicated processing process if the image recording is of high quality and high resolution, and a lack of storage function or basic deterioration of image quality if the process is simple.

The present invention is intended to solve the above problems, and has high quality,
In addition to high resolution, the processing process is simple and long-term storage is possible.Memorized characters, line drawings, images, codes, (1,
0) The objective is to improve the charge retention characteristics of a charge retention medium that can arbitrarily and repeatedly reproduce information with an image quality suitable for the purpose.

[Means to solve the problem]

For this purpose, the charge retention medium of the present invention is a charge retention medium consisting of an electrode layer and a charge retention layer, and is characterized in that a protective film is laminated on the charge retention layer to improve charge retention properties. is an insulating plastic film, or is formed by coating an insulating plastic solution, or is further formed by melt-transferring an insulating molten plastic.

The charge retention medium of the present invention will be explained below.

FIG. 1 is a diagram for explaining each aspect of the charge retention medium of the present invention using a cross-sectional view or a perspective view. FIG. 1 (A) shows an example, and FIG. illustrating an example of
FIG. 1(C) is a perspective view of another embodiment shown in FIG. 1(B), in which 2 is a spacer, 3 is a charge retention medium, 11 is a charge retention layer, 13 is a charge retention medium electrode, and 15 is a charge retention medium electrode. The charge retention layer support 20 is a protective film.

The charge retention layer 11 is made of a highly insulating polymer material in order to suppress the movement of charges, and has a specific resistance of 1014 Ω·c.
It is required to have an insulation property of m or more. Furthermore, it is necessary that the glass transition temperature of the polymeric material constituting the charge retention layer be higher than the operating environment temperature.

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

Examples of thermoplastic resins include polyethylene, vinyl chloride resin, polypropylene, styrene resin, ABS resin,
Polyvinyl alcohol, acrylic resin, acrylonitrile-styrene resin, vinylidene chloride resin, AAS (
ASA) resin, ABS resin, cellulose derivative resin, thermoplastic polyurethane, polyvinyl butyral, poly-4-methylpentene-1, polybutene-1, rosin ester resin, etc., and fluororesins such as polytetrafluoroethylene, fluorinated ethylene Propylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers, their dispersion types or modified types (coating types), polyether ether ketone resins, polyparaxylylene shown by the following structural formula, ( In addition, the above C type is not limited to those with the above structure, but also those in which one of the sites other than the main chain binding site in the benzene ring is substituted with chlorine, and the D type is in which two of the sites are substituted with chlorine. ), etc. Thermosetting resins include unsaturated polyester resins, epoxy resins, phenol resins, urea resins, melamine resins, diallyl phthalate resins, silicone resins, etc., as well as ultraviolet curable resins and electron beams. Energy ray-curable resins such as curable resins include radically polymerizable acrylate compounds, such as ester compounds of acrylic acid or methacrylic acid or derivatives thereof, which have hydroxyl groups at both ends. Specifically, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, 4-hydroxycyclohexyl acrylate, 5-hydroxychlorooctyl acrylate, 2-hydroxy-3 In addition to (meth)acrylic acid ester compounds having one polymerizable unsaturated group such as phenyloxypropyl acrylate, compounds having two polymerizable unsaturated groups represented by the formula % can be used.

Examples of the curable compound having two hydroxyl groups and one or more radically polymerizable unsaturated groups include glycerol methacrylate and the following general 2 (where R and R' are methyl groups or hydrogen, and R1 is a short chain diol residue such as ethylene glycol, propylene glycol, diethylene glycol, butanediol, 1°6-hexanediol, etc.) can be used.

Further, as engineering plastics, polycarbonate, polyamide, acetal resin, polyphenylene oxide, polybutylene lentilphrate, polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polyimide resin, polysulfone, aromatic polyester, polyacrylate, etc. can be used.

In the case of the charge-retaining medium shown in FIG. 1(a), the charge-retaining layer is first coated with a resin or rubber on the electrode by vapor deposition, spuck method, etc., or) by dissolving it in a storage agent. Layers can be formed by dipping.

Further, as the charge retention IJ11, a monomolecular film or a monomolecular cumulative film formed by the Langmuir-Proschede method can also be used.

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

Alternatively, an electrode may be formed on one side of the film by vapor deposition, sputtering, coating, or the like.

Furthermore, a layer for protecting the electrode may be provided thereon, and if further mechanical strength is required, a film or the like having higher mechanical strength may be attached.

Further, photoconductive or conductive fine particles may be present in these insulating polymer materials for charge accumulation.

As photoconductive fine particle materials, inorganic photo-IN materials such as amorphous silicon, crystalline silicon, amorphous selenium, crystalline selenium, cadmium sulfide, and zinc oxide, and organic photoconductive materials such as polyvinyl carbazole, phthalocyanine, and azo pigments are used. be done.

Conductive materials include Group 1A (alkali metals), Group IB (copper group), Group 11A (alkaline earth metals), Group IIB (zinc group), and Group IIIA (aluminum group) of the periodic table. ), Group IIIB (fabric group), Group TVB (titanium group), Group VB (vanadium group), Group VIB (chromium group), Group ■B (manganese group), Group ■ (iron group). The IVA group (carbon group) includes carbon, silicon, germanium, tin, and lead; the VA group (nitrogen group) includes antimony and bismuth; the VIA group (oxygen group) includes sulfur and selenium. , tellurium is used in fine powder form. Further, among the above elements, metals can be used in the form of metal ions, fine powder alloys, organic metals, and complexes. Furthermore, the above elements can be used in the form of oxides, phosphorus oxides, sulfides, and halides. Especially carbon,
Gold, copper, aluminum, etc. are preferably used.

This fine particle layer is formed by vapor depositing its forming material onto the electrode or the charge retention layer using a low pressure vapor deposition apparatus. The particle layer forming material is 10 TOrr to 10-'T
When it is evaporated under a low pressure of about 100.degree.

Further, when a charge retention layer is formed by coating, it may be formed by dispersing fine particles + material A in a charge retention layer forming material solution and coating the mixture on the charge retention layer.

Further, a charge retention reinforcing layer can be provided between the charge retention layer 11 and the electrode surface or on the charge retention layer 11. A charge retention enhancement layer is a layer in which charge is injected when a strong electric field (10'V/cm or more) is applied, but when a low electric field (10'V/cm or more) is applied, charge is injected.
'V/cm or less) refers to a layer in which no charge is injected. As the charge retention reinforcing layer, for example, SiO□, A1□0
3, SiC, SiN, etc. can be used, and as the organic material, for example, a polyethylene vapor deposited film or a polyvaraxylene vapor deposited film can be used.

Further, in order to more stably hold static charges, it is preferable to add a substance having electron donating properties (donor material) or a substance having electron accepting properties (acceptor material) to the charge retention layer 11. Donor materials include styrene, pyrene, naphthalene, anthracene, pyridine, and azine compounds, specifically tetrathiofulvalene (
TTF), polyvinylpyridine, polyvinylnaphthalene, polyvinylanthracene, polyazine, polyvinylpyrene, polystyrene, etc. are used, and -1ffi or a mixture thereof is used. In addition, acceptor materials include halogen compounds, cyanide compounds, nitro compounds, etc.
Specifically, tetracyanoquinodimethane (TCNQ)
Trinitrofluorenone (TNF) and the like are used alone or in combination. The donor material and acceptor material are used by adding about 0.001 to 10% to the resin and the like.

From the viewpoint of insulation, the charge retention layer 11 has a thickness of at least 100%.
A thickness of 0.1 μm or more is required, and from the viewpoint of flexibility, a thickness of 1100 IJ or less is preferable.

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

As a protective film, first of all, when reproducing information! , 11 Recycled rubber with tack to read away, styrene-butadiene rubber, polyisoprene, butyl rubber, Buna-N (butadiene-acrylonitrile rubber), polyvinyl ether (ethyl group or higher hydrocarbon group with alcohol residue) ), polyacrylate ester (
(having an ethyl group or more hydrocarbon group),
Silicone rubber, polyterpene resin, gum rosin, rosin ester, and rosin derivatives, oil-soluble phenolic resin,
Coumaron/indene resin, a type of petroleum-based hydrocarbon resin,
Or a mixture of two or more types with a film thickness of several hundred to several tens of microns.
It can be formed by forming a film of m and sticking it on the surface of a charge holding medium, or it can be formed by sticking an insulating plastic film using a removable adhesive, and the adhesive has a specific resistance of 1014Ω.・Silicone oil of cm or more, dimethyl silicone oil, methylphenyl 7 recon oil, higher fatty acid modified silicone oil, methyl chlorinated phenyl silicone oil, alkyl modified silicone oil, methylhydrogen silicone oil, cyclic polydimethylsiloxane, silicone polyether Polymer, amino-modified silicone oil, epoxy-modified silicone oil,
It is preferable to use one type of insulating oil or a mixture of two or more types.

Alternatively, an insulating plastic film may be laminated onto the charge retention layer using an adhesive.

In addition, insulating plastic is dissolved in a solvent, and when dry, P14
It may be formed by coating by a vapor deposition method, a spinner coating method, etc. to a thickness of several hundred to several tens of micrometers.

Melt transfer materials include EVA (ethylene-vinyl acetate copolymer), EEA (ethylene-ethylene acrylate copolymer), polyamide resin, rosin resin, hydrogenated petroleum resin, pinene resin, hydrocarbon resin, Synthetic rosin resins, terpene resins, waxes, etc. can be used, and if necessary, two or more of the above materials may be mixed, or inorganic powder may be added. Furthermore, it is preferable to use a material that allows the protective layer to be melt-transferred at a temperature that does not attenuate the charges on the charge retention layer due to heating.

Information can be read from above the protective film, and in order to improve the resolution of reading, it is preferable that the protective film be thin. This is because in order to read with high resolution, it is better to place the reading sensor closer to the area where electric charge is accumulated.

If reading resolution is not an issue, the protective film may be thick.

Further, if the protective film is of the adhesive type as described above, the information on the surface of the charge retention layer may be reproduced by peeling off the protective film.

In addition, as shown in Figure 1 (b), the protective film 2 is placed in a non-contact state.
0 may be stacked. In this case, it is preferable to use a plastic film as a protective film and to laminate it on the charge-retaining Jill with a spacer 2 interposed therebetween.

The appropriate distance between the charge retention layer and the protective film is 1 to 50 μm, and the spacer 2 is preferably made of an organic material such as plastic. The spacer 2 and the charge retention layer 11 should be peeled off from each other and the information charge on the charge retention layer 11 can be read.The spacer 2 and the charge retention layer 11 must be adhesively bonded in a removable manner. It's good to let them do it.

The charge retention medium electrode 13 is formed on the charge retention layer support unless a metal is used for the charge retention layer support, and the material thereof is limited as long as the specific resistance value is 106 Ω·cm or less. Metal conductive film, inorganic metal oxide conductive film,
It is an organic conductive film made of quaternary ammonium salt, etc. Such a charge retention layer electrode is formed by vapor deposition, sputtering, C
It is formed by VD method, coating, plating, dipping, electrolytic polymerization, etc. Further, the thickness needs to be changed depending on the electrical properties of the material constituting the charge retention layer electrode and the applied voltage when recording information; for example, in the case of aluminum, the thickness is about 100 to 3000. The charge retention layer electrode is required to have the same optical properties as the support when it is necessary to input information light; for example, if the information light is visible light (4
00 to 700 Ωm), then l'p O([nzO
)-5now), transparent electrodes made by sputtering or vapor-depositing tin oxide, or coating fine powders of these with a binder, gold,
Translucent electrodes made by vapor deposition or sputtering of aluminum, silver, nickel, chromium, etc.
Organic transparent electrodes coated with tetracyanoquinodimethane (TCN), polyacetylene, etc. are used.

The above electrode material can also be used when the information light is infrared light (700 Ωm or more), but in some cases, colored visible light absorbing electrodes can also be used to cut visible light.

Furthermore, when the information light is ultraviolet light (400n+i or less), the above electrode materials can be used, but organic polymer materials that absorb ultraviolet light, soda glass, etc. are not preferred, and quartz glass that transmits ultraviolet light is not preferable. It is recommended to use materials that

The charge retention layer support 15 supports the charge retention layer with strength, but may also be required to have light transmittance. Specifically, when the charge retention medium 3 takes the form of a flexible film, tape, or disk, a flexible plastic film is used, and when strength is required, a rigid sheet, glass, etc. is used. Inorganic materials etc. are used.

The charge retention medium 3 is used together with the photoconductor 1 to record information as a distribution of static charges on the surface or inside of the charge retention layer 11 that constitutes the charge retention medium 3, and the charge retention medium itself It is used as a recording medium. Therefore, the shape of this charge retention medium can take various shapes depending on the information to be recorded or the recording method. For example, an electrostatic camera (patent application filed in 1983 by the same applicant)
-121591), it is in the shape of a general film (single frame or continuous frame) or in the shape of a disk, and when recording digital information or analog information with a laser etc., it is in the shape of a tape or disk. , or in the form of a card.

Next, an electrostatic image recording method using this charge retention medium will be explained with reference to FIG. In the figure, 1 is a photoreceptor, 5 is a photoconductive layer support, 7 is a photoreceptor electrode, 9 is a photoconductive layer, 17
is the power source.

In FIG. 2, exposure is performed from the side of the photoreceptor 1. First, a transparent photoreceptor electrode 7 made of IrO with a thickness of 1000 mm is formed on a photoconductive layer support 5 made of glass with a thickness of 1 body. A photoconductive layer 9 having a thickness of about 10 μm is formed thereon to constitute a photoreceptor l. For this photoreceptor 1, 10μ
The charge retention medium 3 is arranged with a gap of about m. The charge retention medium 3 was obtained by depositing an Ir electrode with a thickness of 1000 m on a charge retention layer support 15 made of glass with an IM thickness, and forming a charge retention layer 11 with a thickness of 10 tIm on this electrode.

First, as shown in the same figure (a), 10
Charge holding medium 3 is set through a gap of about 77 m,
As shown in FIG. 3B, a voltage is applied between the electrodes 7 and 13 by the power source 17. In a dark place, since the photoconductive layer 9 is a high-resistance material, no change occurs between the electrodes. Photoreceptor 1
When light enters from the side, the photoconductive layer 9 in the part where the light entered
exhibits conductivity, and a discharge occurs between it and the charge retention layer 11,
Charges are accumulated in the charge retention layer 11 .

When the exposure is completed, turn off the voltage as shown in the same figure (c).
F, and then charge retention medium 3 as shown in the same figure (d).
By taking out the electrostatic latent image, the formation of the electrostatic latent image is completed.

Note that the photoreceptor 1 and the charge holding medium 3 may be in contact rather than in non-contact as described above, and in the case of contact, a positive or negative charge is applied from the photoreceptor electrode 7 side to the exposed portion of the photoconductive layer 9. Charge is injected, this charge is attracted to the electrode 13 of the three charge retention media, passes through the light guide TL layer 9, and when it reaches the charge retention layer 11, the charge movement stops, and the injected charge is transferred to that part. Accumulated. Then, when the photoreceptor 1 and the charge retention medium 3 are separated, the charge retention layer 11 is separated with the charge stored therein. When this recording method is used as planar analog recording, high resolution can be obtained like silver salt photography.

In this way, the surface charges of the charge retention layer 11 where the 'C image is accumulated as information charges are exposed to the air environment, but in the present invention, the information charges are removed by laminating an insulating protective film on the charge retention layer. It can be stored for a long time without discharging regardless of whether it is in the light or the dark. Information charges may simply accumulate on the surface;
In addition, microscopically, electrons or holes may penetrate into the interior near the surface of an insulator and become trapped within the structure of the material, resulting in long-term storage.

Manual methods for recording information on the charge retention medium of the present invention include 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 consists of a photoconductor 1 made of photoconductive N9 with a photoconductor electrode 7 provided on the front surface, instead of the photographic film used in ordinary cameras; A recording member is constituted by a charge retention medium consisting of a charge retention layer 11 which is opposed to the charge retention layer 11 and has a charge retention medium electrode 13 on the rear surface, and a voltage is applied to the picture electrode to make the photoconductive layer conductive in accordance with incident light. A latent electrostatic image of an incident optical image is formed on a charge storage medium by accumulating charges on a charge storage layer according to the amount of incident light.A mechanical shutter can also be used, and an electric shutter can also be used. Also, the electrostatic latent image can be retained for a long period of time regardless of bright or dark places. In addition, a prism separates the optical information into R, G, and B light components, and a color filter is used to extract them as parallel light, and one frame is formed with 3 cents of charge-retaining media separated into R, G, and B, or one By arranging R and GSB images on a plane and making one frame worth 1 cent, it is also possible to create a color 1 shadow.

For recording methods using lasers, the light sources include argon laser (514,488 nm), helium-neon laser (633 nm), and semiconductor laser (780 nm).
(nm, 810 nm, etc.), and a voltage is applied to the photoreceptor and the charge holding medium with their surfaces brought into close contact with each other or facing each other at a fixed interval. In this case, it is preferable to set the photoreceptor electrode to the same polarity as the carrier of the photoreceptor.

In this state, laser exposure corresponding to image signals, character signals, code signals, and line drawing signals is performed by scanning. Analog recording such as 0 images is performed by modulating the light intensity of the laser, , Digital recording such as line drawings is performed by ON-OFF control of laser light. Halftone dots in the image are formed by subjecting the laser beam to dot-jet control. In addition, photoconductivity 1 in the photoreceptor
The spectral characteristics of g do not need to be panchromatic, but only need to be sensitive to the wavelength of the laser light source.

Next, a method for reproducing a recorded electrostatic image will be explained.

FIG. 3 is a diagram showing an example of a potential reading method in the electrostatic image reproduction method of a charge holding medium of the present invention, and the same numbers as in FIG. 1 indicate the same contents. In the figure, 10 is an insulating 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 section 21 is placed to face the charge storage surface of the charge storage medium 3 from above its protective film, an electric field generated by the charges accumulated on the charge storage layer 11 of the charge storage medium 3 acts on the detection TI 4M23, and the detection An induced charge equal to the charge on the charge storage medium is generated on the electrode surface. Since the capacitor 27 is charged with an equal amount of charge of opposite polarity to this induced charge,
A potential difference occurs between the electrodes of the capacitor depending on the accumulated charge,
By reading this value with a voltmeter 29, the potential of the charge carrier can be determined. Then, the potential reading section 21
The electrostatic latent image can be output as an electric signal by scanning the surface of the charge holding medium with the .

Note that if only the detection electrode 23 is used, the electric field (electric line of force) due to charges in a wider area than the area of the charge holding medium that faces the detection electrode will act, reducing resolution, so a grounded guard electrode 25 is placed around the detection electrode. You can do it like this. As a result, the lines of electric force are oriented perpendicularly to the surface, so that the lines of electric force only act on the area facing the detection electrode 23, and the potential of the area approximately equal to the area of the detection electrode 23 is read. be able to. Since 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 them and the charge retention medium, it is necessary to find and design optimal conditions according to the required performance.

FIG. 4 is a diagram showing a schematic configuration of an electrostatic image reproduction method, in which 61 is a potential reading device, 63 is an amplifier, and 65 is a CR
T, 67 is a printer.

In the figure, a potential reading device 61 detects the charge potential, and an amplifier 63 amplifies the detected output, which can be displayed on a CRT 65 and printed out using a printer 67. In this case, it is possible to arbitrarily select and output the part to be read at any time, and it is also possible to reproduce it repeatedly.

It is also possible to read optically using a material whose optical properties change depending on an electric field, such as an electro-optic crystal. Furthermore, since the electrostatic latent image is obtained as an electrical signal, it can also be used for recording on other recording media, etc., if necessary.

[Effect]

The charge retention medium is formed by laminating a charge retention layer on an electrode substrate, and when exposed to light while facing the photoconductive layer surface on the photoreceptor electrode and applying a voltage between both electrodes, information light is irradiated. Charges move toward the electrode on the charge-retaining medium side in the photoconductive layer, and the polarized charges are accumulated on the surface of the charge-retaining medium or penetrate into the charge-retaining layer, forming a permanent charge-retaining medium. This is the result. However, the surface charge of the charge retention layer gradually attenuates due to moisture in the air, etc., and may be destroyed by external damage. To this end, the present invention improves the charge storage characteristics by laminating the surface of the charge storage layer with an insulating film to protect the charges, thereby making it possible to preserve image information in the charge storage medium for a long period of time. be.

If a protective layer is not provided, the charge will decrease or disappear if the surface of the charge retention medium is physically contacted with a conductor, but if a protective layer is provided, the charge will be reduced or eliminated. Even if static charges are generated on the surface of the protective film due to friction, etc., the surface potential does not decrease, and even if static charges are generated on the surface of the protective film, they can be easily cleaned with a conductor such as water. To reproduce information, this protective film may be peeled off and the information charges accumulated in the charge retention layer may be reproduced, but it is also possible to reproduce them from above the protective film. The information thus accumulated allows the local potential of the electrostatic latent image to be read out and output at any scanning density at any time.

Examples will be described below.

[Example 1] (Method for producing charge retention medium) 1 weight of curing agent (metal catalyst) (trade name CR-L5) was added to a mixed solution having a composition of 10 g of methylphenyl silicone resin and 10 g of xylene-butanol 1:l solvent. %(0,2
g) The mixture was added and stirred well, and Al was coated on a 1,000-person evaporation Ih glass substrate using a doctor blade 4 mil.

After that, drying was performed at 150°C for 1 hour, and the film thickness was 10μ.
A charge retention medium of m was obtained.

(Electrostatic image recording method) As shown in FIG.
The photoconductor (PVK-TNF) 1 and the above-mentioned charge retention medium are stacked facing each other using a 10 μm thick polyester film as a spacer, and the distance between the two electrodes is 7.1.
3, with the photoconductor side negative and the charge retention layer side positive, -70
Apply a DC voltage of 0V.

Next, with a voltage applied, exposure was performed from the photoreceptor side for 1 second using a halogen lamp with an illuminance of 1000 lux as a light source.
After the exposure was completed, the voltage was turned off.

The photoconductive layer 9 in the portion where the light is incident exhibits conductivity, and discharge occurs between the photoconductive layer 9 and the charge retention layer 11, and charges are accumulated in the charge retention layer 11.Next, by taking out the charge retention medium 3, the electrostatic charge is removed. Formation of the latent image is completed.

(Method for forming a protective film) 10 mg of dimethyl silicone oil (viscosity 10.000 cps, Toshiba Silicone ■) was dropped as a protective film on the surface of the charge retention layer on which an electrostatic image was recorded, and then a 20 μm polyester film was layered and laminated. , a polyester film was adhered to the surface of the charge retention layer.

(Charge Retention Characteristics) After recording the electrostatic image, the surface potential of 1100μ is measured with a surface potentiometer on the charge retention layer without a protective film, while the surface potential in the unexposed area is However, as a result of measuring the surface potential from above the aiIla, -10'OV was obtained, which is similar to the surface potential measurement result measured without laminating a protective film.

[Example 2] A 20 μm polyester film was coated with silicone rubber (TSE326; Toshiba Silicon ■) using a doctor blade instead of silicone oil in the protective film forming method of the above example, and after drying at 100°C for 1 hour,
A 2 μm film was formed.

This protective film was laminated on the surface of the charge retention layer with charge retention characteristics on which an electrostatic image was recorded in Example 1. When the surface potential was measured, it was found that it had the same charge retention properties as when silicone oil was used.

(Example 3) A charge retention medium was obtained by forming Al on a glass support having a thickness of 1+ nm by 1000-person vapor deposition, and then polyparaxylylene was formed as a charge retention layer by vapor deposition.

Next, the surface of the charge-retaining layer on which electrostatic charges were recorded was coated with fluorine-containing resin (manufactured by Asahi Glass Co., Ltd.) dissolved in a fluorine-based solvent using a spinner coating method to form a 3 μm layer.
A protective layer with a thickness of . As a result of measuring the surface potential from above this protective film, a value of 1100 V was obtained, which is the same as the surface potential measured without laminating the protective film and the ii film.

[Example 4] Stehelite Ester 10 (manufactured by Rika Vercules) was applied to the surface of a 6 μm thick polyester film (manufactured by Toshi), one side of which was released with a silicone release agent, and 30% dissolved in monochlorhenzene. The solution was applied with a roll coater to a dry thickness of 7 μm to prepare a melt transfer film.

A charge retention medium prepared in the same manner as in Example 1 was charged to a surface potential of 100 V, and then combined with the above film for melt transfer, charge retention was performed using a heat roll heated to 60°C using a heat sealer. It was produced by transferring a protective layer onto a medium.

The result of measuring the surface potential from above this protective film was 110%, which was the same as the surface potential measurement result measured without laminating the protective film.
It was confirmed that V was obtained and that a protective film could be formed by melt transfer.

[Example 5] FIG. 5 is a diagram showing changes over time in charge retention characteristics of the charge retention medium of Example 1.

Lines A and B in the figure show the case in which no protective film was laminated in Example 1, and line A was measured after being left at a temperature of 25°C and a humidity of 30%, after 3 months had elapsed. However, the surface charge on the charge retention medium hardly attenuated. In addition, the B line was measured after being left at a temperature of 40°C and humidity of 75%, but after one week, it was approximately 25%
There was only attenuation.

[Example 6] FIG. 6 is a diagram showing changes over time in charge retention characteristics of the charge retention medium of Example 3.

In the figure, ○ indicates that the mouth is not laminated with a protective film, × and Δ indicate protection 1.
It shows the charge retention characteristics of a stack of 1g, and O1x is:
Measurements were taken after being left at room temperature and humidity of 50%, and measurements were taken after being left at a temperature of 40° C. and humidity of 95%.

As can be seen from this figure, the charge retention property is significantly improved by laminating the protective film. That is, O1×
was measured after being left at room temperature and 50% humidity, but even after one month, the surface charge on the charge retention medium with the protective layer laminated with the protective film (marked with an x) was: There was no attenuation compared to the case where no protective layer was laminated (marked O). In addition, Δ was measured after being left at a temperature of 40°C and a humidity of 95%, and after about one month, the test without a protective film (kuchi) had a 45% attenuation.
The one in which a protective film was laminated (marked with △) had attenuation of only about 35%.

In addition, when the medium was not provided with a protective film, the charge completely disappeared when the medium was immersed in water, but when the medium was provided with a protective film, the potential could not be read from above the protective film due to immersion in water, but the protective film was peeled off. When we measured the potential on the surface of the medium, we found that
The original potential was measured and no change in resolution was observed.

[Reference Example 1]...Organic photoreceptor (PVK-TNF)
Preparation method Poly N-vinyl Lupadzul 10g (Kokunan Kaori Co., Ltd.)
), 2,4.7-1-linitrofluorenone 10g1
2 g of polyester resin (binder: Byron 200 manufactured by Toyobo Co., Ltd.), 90% tetrahydrofuran (THF)
A mixed solution having a composition of g was prepared in a dark place, and In2O2-
It was applied using a doctor blade to a glass substrate (1fflI11 thickness) sputtered with Sn02 to a film thickness of about 1000 nm, and dried with ventilation at 60°C for about 1 hour, resulting in a film thickness of about 10 nm.
A photosensitive layer with a photoconductive layer of μm was obtained. In addition, in order to completely dry the sample, it was further air-dried for one day before use.

〔Effect of the invention〕

The present invention provides a charge retention medium consisting of an electrode layer and a charge retention layer with high charge retention properties, in which a protective film is formed on the charge retention layer and the surface of the charge retention layer is laminated with an insulating film to protect the charge retention layer. It improves the retention characteristics and makes it possible to preserve image information on a charge retention medium for a long period of time, and has the effect of not attenuating the surface potential even when there is physical contact between conductors. When reproducing information, the protective film may or may not be peeled off, allowing the accumulated information charges to be reproduced.

The image charge held in this way allows the local potential of the electrostatic latent image to be read out and output at any scanning density at any time, so it is possible to take a silver halide photograph and then print that photograph at an appropriate time. By optically scanning the images and re-outputting them, a recording holding medium is obtained that can output high-quality original images and output them at arbitrary times. Furthermore, by using the electrostatic charge recording and holding medium of the present invention, physical or chemical means such as a developing means are not required when detecting potential directly, so it is possible to create an inexpensive and simple recording and reproducing system. It is something that can be done.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the charge retention medium of the present invention, FIG. 2 is a diagram for explaining an electrostatic image recording method on the charge retention medium, and FIG. 3 is an example of a DC amplification type potential reading method. Figures 4 and 5 are diagrams showing a schematic configuration of electrostatic image reproduction according to the present invention.
This figure is a diagram showing the charge retention characteristics of the charge retention medium having the protective film produced in Example 1, and FIG. 6 is a diagram showing the charge retention properties of the charge retention medium having the protection film produced 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
12 is a charge retention layer, 12 is a charge retention layer missing portion, 13 is a charge retention medium electrode, 15 is a charge retention layer support, 17 is a power source, and 2
0 is a protective layer, 21 is a potential reading section, 23 is a detection electrode,
25 is a guard electrode, and 27 is a capacitor. Ivy 1 drawing Applicant Dainippon Printing Co., Ltd. agent Patent attorney (1) Nobuhiko (other 4 people) (b)

Claims (4)

[Claims] (1) A charge-retaining medium comprising an electrode layer and a charge-retaining layer, the charge-retaining medium having a protective film characterized in that a protective film is laminated on the charge-retaining layer to improve charge-retaining properties. (2) The charge retention medium having a protective film according to claim 1, wherein the protective film is an insulating plastic film. (3) The charge retention medium having a protective film according to claim 1, wherein the protective film is formed by coating an insulating plastic solution. (4) The charge retention medium having a protective film according to claim 1, wherein the protective film is formed by melt-transferring an insulating molten plastic.