JPH0446347A - Information recording medium - Google Patents

Abstract

PURPOSE:To obtain a stable frost image not causing decay of electric charge information even at a heat development temperature of 90 - 110 deg.C by using a pinene polymer having a molecular weight of 500 - 10,000 as a recording layer. CONSTITUTION:The information recording medium 10 is formed by laminating the recording layer 11 made of the pinene polymer having a molecular weight of 500 - 10,000 on an electrode 13. After the information charge has been accumulated on the surface of this recording layer 11, a frosty visible image corresponding to the information charge is formed by heating the pinene polymer or leaving it in a solvent vapor. The pinene polymer is obtained from alpha-pinene or beta-pinene and if its molecular weight is <=500, its workability is lost and if >=10,000, it is made difficult to form the frost image, and its softening point is, preferably, 60 - 160 deg.C.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an information recording medium.

[Conventional technology]

For conventional information recording media, first, an information charge is applied to the surface of a thermoplastic resin layer in a vacuum using an electron beam, and after charging, the thermothermable resin is heated to soften it, and the surface is formed with uneven portions corresponding to the amount of charge. It is known to form a frost image consisting of

On the other hand, recording media that do not require a vacuum system include those in which a photoconductive layer and a thermoplastic resin layer are sequentially laminated on an electrode;
Alternatively, thermoplastic recording media with a single-layer structure having thermoplasticity and photoconductivity are known, and for recording, the entire surface is initially charged by corona charging, imagewise exposed, and the entire surface is charged again and then heat-developed or solvent vapor is used. It is also known that a frost image corresponding to imagewise exposure is formed by developing the image in the film.

[Problem to be solved by the invention]

However, among the above-mentioned information recording media, those that perform image formation in a vacuum require large equipment, and depending on the thermoplastic resin used, it is often difficult to form a frost image, and Those having a conductive layer require operations such as charging the entire surface by corona charging or the like for recording.

The present invention relates to an information recording medium that has a simple image forming method and is capable of forming a high-quality, high-resolution frost image.

[Means to solve the problem]

The information recording medium of the present invention has a molecular weight of 500 to 10 on the electrode.
This is an information recording medium in which 000 pinene polymer recording layers are laminated, and after information charges are accumulated on the surface of the sample recording layer, the surface of the recording layer is heated or left in solvent vapor. It is characterized by forming a frost-like visible image corresponding to information charges.

FIG. 1 is a cross-sectional view of the information recording medium of the present invention, with 10
1 is an information recording medium, 11 is a pinene polymer recording layer, 13 is an electrode, and 15 is a support.

The pinene polymer is a polymer of α-pinene or β-pinene, which is a monoterpene hydrocarbon, and in the present invention, it is a pinene polymer obtained from α-pinene or a polymer obtained from β-pinene, Its molecular weight is 500-10000
If the molecular weight is less than 500, there is no moldability, and 1
If it exceeds 0000, it becomes difficult to form a frost image. The softening point of these pinene polymers of the present invention is preferably 60°C to 160°C.

Pinene polymers obtained from α-pinene are, for example, manufactured by Rika Herkikoles ■, trade name Picolite A-115 (softening point, ring and ball method: 132°C, molecular weight 1000, glass transition temperature 64.0°C), and from β-pinene. The obtained polymer is
For example, manufactured by Rika Vercules □□□, product name Picolite S
-115 (softening point: 137°C, molecular weight: 3000) and the like can be used.

Pinene polymer is dissolved in a solvent such as xylene, toluene, benzene, chloroform, dichloroethane, n-hexane, etc., and is coated on the electrode by a coating method such as blade coating, dipping, or spinner coating, and after drying, the film thickness is is 0. The thickness is preferably 1 μm to 5 μm; if the film thickness is less than 0.1 μm, no surface potential will be built up, or the charge will leak before heat development, making it impossible to form unevenness by heat development, and if the film thickness exceeds 5 μm Unless a high surface potential is applied, unevenness cannot be formed, or the resin crystallizes during coating, causing peeling and coating failure, which is not preferable.

Further, the electrode may be supported by a support, and is not limited as long as it is formed on a support except when a metal plate is used as the support, and the specific resistance value is 10'Ω・cm or less. , an inorganic metal conductive film, an inorganic metal oxide conductive film, an organic conductive film such as a quaternary ammonium salt, etc. can be used.

For example, indium oxide-tin oxide (In2o! 5n0
2) Transparent electrodes such as (ITO) film, tin oxide film, etc.
Al % A gs Electrodes made by vapor deposition or sputtering of Ni, Cr, etc., organic electrodes coated with tetracyanoquinodimethane (TCNQ), polyacetylene, etc., and silicon substrates whose surfaces are thermally oxidized are used. can do.

In particular, the thickness of the pinene polymer recording layer can be reduced by using a substrate with a layer that prevents the injection of opposite charges from the electrode, such as a thermally oxidized silicon substrate on the surface, as an electrode in an information recording medium. , it is possible to make the frost image higher in quality and resolution.

There are no particular restrictions on the thickness or material of the support as long as it has a certain level of strength to support the information recording medium, such as a flexible plastic film with a thickness of about 1 mrn, glass, or plastic. A sheet etc. is used.

Next, the method of electrostatic information recording on an information recording medium of the present invention will be explained with reference to FIG.

Information is recorded on the information recording medium of the present invention using a photoreceptor in which a photoconductive layer such as an a-selenium layer or an organic photoconductive layer is laminated on an electrode.

As shown in FIG. 2(a), an indium oxide-tin oxide (ITO) film having a thickness of 1000 mm is deposited on a glass support 5 having a thickness of 1 mm.
) A photoreceptor 1, which is formed by laminating electrodes 7 and further laminating a photoconductive layer 9 of about 10 μm, and an information recording medium 10 are placed facing each other with a gap of about 10 μm interposed therebetween.

Next, as shown in FIG. 2(b), the electrode 7 is
．． A voltage is applied between 13. In the dark, the photoconductive layer 9 is a high-resistance material, so if the voltage applied to the gap is equal to or lower than the discharge start voltage according to Paschen's law, no change occurs between the electrodes.

When information light 18 is incident on the photoreceptor 1 side, the photoconductive layer 9 in the area where the information light is incident exhibits conductivity, a discharge occurs, and information charges are accumulated on the information recording layer.

Then, as shown in (C) of the same figure, the power supply 17 is turned off and the information recording medium 3 is separated from the photoreceptor 1 ((d) of the same figure).
).

Next, by heating with information charges accumulated on the surface, a frost image is formed on the surface by the accumulated charges.

The heating method may be a resistance heating method or a heating means such as an oven.

The heating temperature or heating time varies depending on the type and softening point of the resin. In particular, when the heating temperature is higher than the temperature at which the resin completely softens, the charge is attenuated and the electrostatic force ceases to work, and at the same time, the unevenness that once appeared disappears due to the leveling effect. Therefore, it is preferable to heat at a temperature slightly lower than the softening point of the resin.

For example, β where the pinene polymer recording layer has a softening point of 115°C.
- When made of pinene polymer, the heating temperature is 90°C to 1
It is recommended to heat at 10°C, preferably 95°C to 100°C, for 1 minute to 3 minutes. If the heating temperature is less than 90°C, the resin will not soften and a sufficient frost image will not be formed;
If the viscosity of the resin is exceeded, the viscosity of the resin becomes too low, resulting in a problem that the image becomes blurred or the image is erased at the same time. Furthermore, if the heating time is too long, the fluidity of the softened resin will cause the image to blur, which is not preferable.

Furthermore, instead of heating and developing the information recording medium on which the electrostatic latent image has been formed, a frost image can be similarly formed by leaving it in a closed container filled with solvent vapor such as xylene, acetone, methyl ethyl ketone, toluene, etc. be able to.

Although the case where electrostatic information is recorded using a photoreceptor has been described above, the method of recording electrostatic information on an information recording medium of the present invention can also be performed using other methods such as corona charging, electrode needle heating, or ionization. Electrostatic recording using a flow head, recording method using an optical printer such as a laser printer, etc. may be used.

[Operation and Effects of the Invention] Conventionally, styrene resin, terpene resin, rosin ester, coumaron resin, polyvinyl chloride resin, etc. have been known as thermoplastic recording materials, but those with a molecular weight of 500 to
When using 10,000 pinene polymer as the recording layer,
Compared to other thermoplastic recording materials, it is possible to create a thermally stable frost image without causing any attenuation of the information charge formed on the resin surface even when the heat development temperature is 90°C to 110°C. This is what I found.

It has also been found that by setting the film thickness to 0.1 μm to 5 μm, the frost image can be made clearer.

That is, the information recording medium of the present invention can obtain an excellent frost image even under a vacuum condition, does not require a photoconductive layer for recording, and can be easily used for recording.

Further, by recording information by exposing a photoreceptor to light while applying a voltage, there are the following advantages.

First, since a conventional photoconductive layer is not required as an information recording medium for forming frost, when using transmitted light or reflected light to reproduce a frost image, there is no effect due to coloring of the photoconductive layer. can be eliminated and a transparent frost image can be obtained.

Secondly, compared to creating a frost image using an electron beam, since information can be recorded in the atmosphere, a frost image can be created with a simple device.

Thirdly, by using the exposure method when voltage is applied, it is possible to form a frost image having particularly good gradation, which makes it an excellent frost image.

The information recording medium of the present invention formed in this way can be made suitable for an overhead projector document projected by a transmission type or a reflection type.

The present invention will be explained below with reference to Examples.

[Example 1] In a three-bottle flask equipped with a stirrer, a condenser, and a thermometer,
Add 200g of distilled β-pinene (manufactured by Tokyo Kasei, distilled under reduced pressure) and 200g of dehydrated toluene, and boil with stirring.
Add 40 g of anhydrous AlCl* (manufactured by Junsei Kagaku ■) and
Polymerization was carried out at ~45°C for 2 hours.

Next, the reaction mixture was transferred to a separating funnel, 100 mJ of 5% aqueous hydrochloric acid solution was added, and after shaking well, the upper layer was separated.
It was washed with a 0% aqueous sodium hydroxide solution and then with water.

Then, after drying with anhydrous calcium chloride, the solvent was removed,
Furthermore, after dissolving in chloroform 2000k, the product was purified by reprecipitation with a large amount of methanol to obtain a β-pinene polymer in a yield of 96 g (yield: 48%).

The molecular weight of this polymer was 5t (OOBX GTC-KF-
When measured with a high performance liquid chromatograph I (LC-802^ (manufactured by Tosoh) using a 800 (7) column, it was 5760 in terms of polystyrene. The softening point and glass transition temperature were determined to be 130°C and 75°C, respectively, by a thermal analysis test using Seiko Electronics Co., Ltd. (manufactured by Seiko Electronics Co., Ltd.). This was done in the same way as the example.

Next, 9 g of the obtained β-pinene polymer was added to 41 g of xylene.
Prepare a 18% by weight solution dissolved in ITO electrode (5% by weight)
I on a glass substrate deposited with 50A, 80Ω/hole)
It was applied onto the TO electrode using a spin coater at 200 rpm.

After that, it was dried at 60℃ for 1 hour, and the β-
A pinene polymer film was formed to obtain an information recording medium of the present invention.

This information recording medium and a photoreceptor formed by laminating an organic photoconductive layer on a transparent electrode are arranged so that the recording layer and the organic photoconductive layer of the photoreceptor face each other as shown in FIG. The polyester film was placed through a gap formed using a spacer.

Next, image exposure is performed from the photoconductor side, and at the same time, the photoconductor electrode is set to 700 V between the recording medium and both electrodes of the photoconductor with a negative voltage applied.
, is applied for 1.0 seconds to form an electrostatic latent image on the medium, and then
It was heated in an oven at 95° C. for 3 minutes to obtain a vine frost image with clearly distinguishable patterns. When this frost image was observed under a microscope (1,000x magnification), the frost frequency was approximately 4.
A sample with a cycle rate of 50 cycles/mm was obtained.

However, the frost frequency here is the number of cycles per la+m, which is measured by microscopic observation, with one cycle consisting of adjacent protrusions and protrusions or depressions and depressions caused by development.

Hereinafter, those referred to as frost frequencies were subjected to similar measurements.

[Example 2] In a three-bottle flask equipped with a stirrer, a condenser, and a thermometer,
Add 100 g of distilled α-pinene (manufactured by Tokyo Kasei, distilled under reduced pressure) and 200 g of dehydrated toluene, and add 5 g while stirring.
Drop anhydrous AlCl5 (manufactured by Junsei Kagaku ■) and
Polymerization was carried out at 5°C for 2 hours.

Next, the reaction mixture was transferred to a separatory funnel, 50+nIl of 5% aqueous hydrochloric acid solution was added, and the upper layer was separated after shaking well.
It was washed with a 10% IJ hydroxide aqueous solution and then with water.

Then, after drying with anhydrous calcium chloride, the solvent was removed,
Plus 100mj of chloroform! The resulting product was purified by reprecipitation with a large amount of methanol to obtain 12 g (yield: 2%) of an α-pinene polymer (softening point: 110° C., molecular weight: 600).

Next, using the obtained α-pinene polymer, Example 1
In the same manner, an α-pinene polymer film having a thickness of 5500 was formed to obtain an information recording medium of the present invention.

An electrostatic latent image was formed on the obtained medium in the same manner as in Example 1, and then heated in an oven at 95° C. for 3 minutes to obtain a frost image in which the pattern was clearly distinguishable and similar to that in Example 1.

[Example 3] β-pinene polymer (manufactured by Rika Harkiniles ■, trade name Picolai) S-115, softening point 115°C, molecular weight 1710)
A 18% by weight solution was prepared by dissolving 9 g in 41 g of xylene, and it was applied at 200 Qrpm using a spin coater onto an ITO electrode on a glass substrate on which ITO electrodes (550 people, 80 Ω/portion) had been deposited.

After that, it was dried at 60℃ for 1 hour, and the β-
A pinene polymer film was formed to produce an information recording medium of the present invention.

An electrostatic latent image was formed on the obtained medium in the same manner as in Example 1, and then heated in an oven at 95° C. for 3 minutes to obtain a frosted image with clearly distinguishable patterns. When this frost image was observed under a microscope (1000 times magnification), a frost frequency of approximately 450 cycles/cm was obtained.

Moreover, in the information recording medium produced in this way,
The relationship between the heating temperature and the amount of attenuation of the surface potential can be measured using a thermal stimulation current measuring device (Toyo Seiki ■).
(manufactured by).

The results are shown in FIG. According to this, it can be seen that the information recording medium of the present invention maintains a sufficient potential for development at a high temperature of 90°C to 110°C.

[Example 4] In Example 3, instead of the β-pinene polymer, α-pinene polymer (manufactured by Rika Percules Kan, trade name Picolai) A was used.
-115, softening point 115°C, molecular weight 833),
ITO electrodes (550 people, 80Ω/
A spin coater was used to coat the ITO electrode on the glass substrate on which the film was deposited at 11,000 rpm.

After that, it was dried at 60℃ for 1 hour, and the film thickness was 8000.
A pinene polymer film was formed to produce an information recording medium of the present invention.

An electrostatic latent image was formed on the obtained medium in the same manner as in Example 1, and then heated in an oven at 100° C. for 3 minutes to obtain a frost image with a frost frequency of about 400 cycles/mm.

[Example 5] Except in Example 3, the β-pinene polymer solution was applied using a spin coater at 11,000 rpm and dried at 60° C. for 1 hour to form a β-pinene polymer film with a thickness of 8,500. An information recording medium of the present invention was produced in the same manner as in Example 3.

An electrostatic latent image was formed on the obtained medium in the same manner as in Example 1, and then heated in an oven at 95° C. for 3 minutes to obtain a frost image with a frost frequency of about 400 cycles/a++n.

[Example 6] Using the medium created in Example 3, an electrostatic latent image was formed on the medium in the same manner as in Example 1, and then information was recorded in a closed container heated to 60°C and filled with xylene vapor. The medium was left to stand for 5 minutes, and a 70 stroke image similar to Example 3 was obtained on the medium.

[Example 7] Resistivity 1 created by CZ method by doping with phosphorus
The surface of a silicon substrate cut to a thickness of 600 μm using the (1°0.0) plane of ~100 Ω・cm silicon crystal was thermally oxidized. , product name Picolai) S-
115, softening point 115° C., molecular weight 1710) dissolved in 41 g of xylene was applied at 4000 rpm using a spin coater.

After that, it was dried at 60℃ for 1 hour, and the β-
A pinene polymer film was formed to produce an information recording medium of the present invention.

The obtained medium was subjected to pattern exposure in the same manner as in Example 1 using a silicon substrate as an electrode to form an electrostatic latent image on the recording medium of the present invention.

It was then heated in an oven at 95° C. for 3 minutes to obtain a vine frost image with clearly distinguishable patterns.

When this frost image was observed under a microscope (1000 times magnification), a frost frequency of about 550 cycles/+nm was obtained.

It can be seen that the information recording medium can have higher resolution than the information recording medium of Example 3.

In addition, with the same configuration as Example 3, the film thickness of β-pinene polymer was increased to 3.
When electrification was performed in the same manner on 000 people, the charged potential attenuated immediately and no frost image could be obtained.

[Comparative Example 1] In a three-bottle flask equipped with a stirrer, a cooler, and a thermometer, 1
Add 00g of distilled β-pinene (manufactured by Tokyo Kasei ■, distilled under reduced pressure) and 100g of dehydrated toluene, and while stirring while keeping it at 0℃, add 1g of BP, ・(ET), O (manufactured by Junsei Kagaku ■). was added dropwise, and polymerization was carried out for 2 hours.

Next, the reaction mixture was transferred to a separatory funnel, and 100 mA of 5% aqueous hydrochloric acid solution was added thereto (after shaking, the upper layer was separated and 1
It was washed with a 0% aqueous sodium hydroxide solution and then with water.

Then, after drying with anhydrous calcium chloride, the solvent was removed,
Plus 50mj of chloroform! The β-pinene polymer (softening point: 59°C, molecular weight: 480) was obtained in a yield of 30g (yield: 30°C) by reprecipitation with a large amount of methanol.
%).

Next, using the obtained β-pinene polymer, Example 1
In the same manner, a β-pinene polymer film having a thickness of 5,500 layers was formed to obtain an information recording medium.

An attempt was made to form an electrostatic latent image on the obtained medium in the same manner as in Example 1, but the latent image rapidly attenuated and could not be charged.

[Comparative Example 2] As the thermoplastic resin in Example 3, α-methylstyrene polymer (manufactured by Rika Herkikoles ■, trade name Crystalex 1120, softening point 1) was used instead of β-pinene polymer.
After producing an information recording medium in the same manner as in Example 3 using 20° C. and molecular weight 1710), an electrostatic latent image was formed in the same manner as in Example 1, and heat-developed in an oven at 100° C. for 5 minutes. Couldn't discern pattern.

In addition, when we measured the amount of thermal stimulation current depending on the heating temperature,
The surface potential was completely attenuated near the temperature at which α-methylstyrene softens.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the information recording medium of the present invention, and FIG.
FIG. 3, which is a diagram for explaining the method of forming an electrostatic latent image on an information recording medium of the present invention, is a diagram for explaining the results of measurement of thermally stimulated current in the information recording layer of the present invention. In the figure, 1 is a photoreceptor, 5 is a support, 7 is an electrode, 9 is a photoconductive layer, 10 is an information recording medium, 11 is a recording layer made of a pinene polymer, 13 is an electrode, 15 is a support, and 17 is a A power source and 18 indicate information light. Applicant Dainippon Printing Co., Ltd. Agent Patent attorney Nobuhiko Uchida (7 others) Figure 1 Figure 3 = t JjL ('C)

Claims (3)

[Claims] (1) An information recording medium in which a recording layer of a pinene polymer with a molecular weight of 500 to 10,000 is laminated on an electrode, and after information charges are accumulated on the surface of the recording layer, the pinene polymer is heated or exposed to solvent vapor. An information recording medium that forms a frost-like visible image corresponding to information charges on the surface of the recording layer when left in the medium. (2) The information recording medium according to claim 1, wherein the information charge accumulating means is based on exposure when a voltage is applied to a photoreceptor having an electrode and placed opposite to the photoreceptor. (3) The information recording medium according to claim 1, wherein the electrode is a silicon substrate subjected to thermal oxidation treatment.