JP2011185942A - Image recording medium and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem of interfacial crystallization on the interface with an electrode, in an electrostatic recording material having a photoconductive layer for reading with a-Se as a main constituent. <P>SOLUTION: In the electrostatic recording material 10, an electrode layer 5 having translucency to read light, the photoconductive layer 4 for reading that exposes conductivity by receiving the illumination of read light with a-Se as a main constituent, a charge transfer layer 3 for forming an energy storage unit 23 for accumulating a latent image polarity charge being generated at a photoconductive layer 2 for recording, the photoconductive layer 2 for recording that exposes conductivity by receiving the illumination of record light with a-Se as a main constituent, and an electrode layer 1 having translucency to the record light are stacked in this order on a support 8 having translucency to read light. A state being essentially equivalent to the state where a thin layer for inhibiting interfacial crystallization is provided at a side where the read light enters most by doping As by 0.5-40 atom% at the interface between the photoconductive layer 4 for reading and the electrode of the electrode layer 5 as a substance for inhibiting interfacial crystallization. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image recording medium capable of recording image information as an electrostatic latent image.

  Conventionally, for example, in medical X-ray photography, a photoconductor sensitive to X-rays (for example, using selenium Se) has been used in order to reduce exposure dose received by a subject and improve diagnostic performance. A system is disclosed in which an electrostatic latent image is recorded on the image recording medium by X-rays using an image recording medium and then the electrostatic latent image is read (for example, Patent Documents 1 to 6, Non-Patent Documents). References 1, 2, etc.).

Specifically, for example, in Patent Document 4 described above, a conductive substrate made of a relatively thick 2 mm-thick Al or the like and having transparency to radiation as an electromagnetic wave for recording (hereinafter also referred to as recording light) is disclosed. On the recording light side electrode layer, a recording photoconductive layer having a thickness of 100 to 500 μm mainly composed of a-Se (amorphous selenium), and AsS ₄ , As ₂ S ₃ , As having a thickness of 0.01 to 10.0 μm. An intermediate layer (trap layer) made of ₂ Se ₃ or the like in which the latent charge of the latent image generated in the recording photoconductive layer is accumulated as a trap, and for reading with a thickness of 0.5 to 100 μm mainly composed of a-Se A photoconductive layer and a reading light side electrode layer made of Au or ITO (Indium Tin Oxide) with a thickness of 100 nm and having transparency to reading electromagnetic waves (hereinafter also referred to as reading light) are laminated in this order. An image recording medium is disclosed .

  Further, in particular, it is preferable to use the reading light side electrode layer as a positive electrode because it is possible to utilize the mobility of positive hole of a-Se, and S // In order to prevent N degradation, it is disclosed that a blocking layer made of an organic substance is provided between the reading light side electrode layer and the reading photoconductive layer. This image recording medium is a multilayer recording medium having high dark resistance and excellent read response speed.

  Here, in order to improve the S / N of the image and further to perform parallel reading (mainly in the main scanning direction) to shorten the reading time, a large number of elements (linear electrodes) are used as electrodes of the reading light side electrode layer. ) May be used in stripe electrodes arranged at a pixel pitch (for example, Patent Document 7 by the present applicant). However, in the laminated structure of the image recording medium described in Patent Document 4, the reading light side electrode layer must be formed after the reading photoconductive layer is formed in the final manufacturing process, and the stripe electrode is formed. It is difficult to form. In order to perform microfabrication of electrodes for forming stripe electrodes, it is necessary to perform photoetching used in semiconductor manufacturing. During this process, a high temperature (for example, a baking process for photoresist) is required. This is because a-Se, which normally requires a process and forms a photoconductive layer that has already been formed, cannot withstand such high temperatures and deteriorates its properties. Furthermore, since the alkaline developer used in the photoresist development process and a-Se come into contact with each other to produce harmful gas, there is a problem that the process becomes complicated and the cost increases due to the removal.

On the other hand, the applicant of the present application disclosed in Patent Document 7 is a recording light side electrode layer made of SnO ₂ (nesa film) and having transparency to radiation as recording light, and 50 to 50 containing a-Se as a main component. A recording photoconductive layer having a thickness of 1000 μm and a storage unit for accumulating the latent image polar charge generated in the recording photoconductive layer made of organic matter or a-Se doped with 10 to 200 ppm of chlorine (Cl). A charge transport layer for forming at the interface with the layer, a photoconductive layer for reading mainly composed of a-Se, and a reading light side electrode layer having transparency to the reading light in this order. An image recording medium (electrostatic recording medium) is proposed.

  When manufacturing this image recording medium, it is not specifically stated whether the film is formed sequentially from the recording light side electrode layer or conversely from the reading light side electrode layer. It was good too. However, as the reading light side electrode layer, a transparent glass substrate as a support provided with a conductive material such as a nesa film is proposed, and the reading light side electrode layer is used as a positive electrode and a high-definition pixel “To form comb teeth with a sufficiently narrow interval by semiconductor formation technology”, that is, to make the electrodes on the reading light side electrode layer into stripe electrodes divided by the pixel pitch. In this case, a stripe electrode is first formed on a transparent glass substrate by photoetching or the like, and then a reading photoconductive layer to a recording light side electrode layer are sequentially formed. Although specific numerical values of the pixel pitch are not shown directly, the pixel pitch can be set to 50 to 50 because it enables high S / N while maintaining high sharpness in medical X-ray imaging. It is conceivable to those skilled in the art that 200 μm is used.

Further, in Patent Document 7, like those described in Patent Document 4 is provided with a 500Å about blocking layer made of inorganic material such as CeO ₂ between the reading light side electrode layer and the reading photoconductive layer Thus, it has also been proposed to prevent S / N deterioration due to direct injection of positive charges charged in the reading light side electrode layer.

  On the other hand, the inventors of the present application have found the following points by further examination of the image recording medium proposed in Patent Document 7 above.

1) In manufacturing, a method of forming a stripe electrode by photoetching after forming a relatively thin 50 to 200 nm thick ITO film on a transparent glass substrate as a reading light side electrode layer is inexpensive. This is suitable because a high-definition stripe pattern can be formed.
2) It is excellent in terms of high dark resistance that the recording photoconductive layer is a-Se having a thickness of 50 to 1000 μm.
3) As a charge transport layer, a first hole transport layer having a thickness of 0.1 to 1 μm made of a thin organic substance that charges electrons to form a power storage unit, and transports holes at high speed and has few hole traps. The stacked hole transport layer formed by laminating two layers with the second hole transport layer having a thickness of 5 to 30 μm made of “a-Se doped with 10 to 200 ppm of Cl” is a point of afterimage and reading response speed. Is excellent.
4) It is excellent in terms of high dark resistance that the photoconductive layer for reading is 0.05 to 0.5 μm thick a-Se.
5) The charge transport layer is composed of a first charge transport layer made of PVK or TPD having a thickness of 0.1 to 1 μm, and a second charge transport mainly composed of 5 to 30 μm thick a-Se doped with 10 to 200 ppm of Cl. When the layered hole transport layer is made of a layer, the first charge transport layer has a strong insulating property against the latent image polar charge, and the second charge transport layer has a fast transport property of the transport polar charge. Therefore, it is possible to make the charge transport layer ideal in terms of afterimage and read response speed, but the second hole transport layer is made of a-Se having a thickness of 5 to 30 μm. If it is replaced and the structure also serves as a reading photoconductive layer, relatively good results can be obtained, and the manufacture becomes simple.

  From the above, the image recording medium described in Patent Document 7 is a multilayer recording medium having a high dark resistance and an excellent read response speed, and is composed of a layer mainly composed of a-Se as a whole. It is desirable that

U.S. Pat. No. 4,176,275 US Pat. No. 5,268,569, US Pat. No. 5,354,982 US Pat. No. 4,535,468 JP-A-9-5906 U.S. Pat. No. 4,961,209 Japanese Patent Application No. 10-232824

"23027 Method and devisce for recording and transducing an electromagnetic energy pattern"; Research Disclosure June 1983 "X-ray imaging using amorphous selenium"; Med Phys.22 (12)

  By the way, as is well known, an amorphous selenium film has a problem that interfacial crystallization proceeds at the interface with other substances in the deposition process during film formation. For this reason, among those described in Patent Document 7, after forming the reading light side electrode layer on a support such as a glass substrate, the reading photoconductive layer is formed of the reading photoconductive layer. In the vapor deposition process and the subsequent vapor deposition process of the recording photoconductive layer, interface crystallization proceeds at the interface between the electrode material and a-Se, and charge injection from the electrode increases, so that the S / N decreases. Arise. When a transparent oxide film, particularly ITO, is used as the electrode material, the interface crystallization at the interface between the electrode material and a-Se proceeds remarkably, and the S / N reduction becomes significant, so an improvement is desired.

  Further, in the image recording medium as described above, the electrostatic latent image is recorded by accumulating the latent image polarity charge generated in the recording photoconductive layer in the power storage unit by the recording electromagnetic wave transmitted through the subject. Then, reading is performed by combining the charge pair generated in the reading photoconductive layer by the reading electromagnetic wave transmitted through the reading light side electrode layer with the latent image polarity charge in the power storage unit.

  Here, the generation efficiency of the charge pair generated in the reading photoconductive layer is proportional to the strength of the electric field formed between the power storage unit and the reading light side electrode layer. Therefore, when the dose of electromagnetic waves for recording that has passed through the subject is on the low dose side, the latent image polarity charge accumulated in the power storage unit is small, and thus formed between the power storage unit and the reading light side electrode layer. The electric field strength is weakened, and the charge pair generation efficiency in the reading photoconductive layer is lowered. This reduction in the generation efficiency of the charge pair results in a decrease in sensitivity to the reading light of the image recording medium, resulting in an increase in cost due to an increase in the amount of reading light.

  The present invention has been made in view of the above circumstances, and in the image recording medium as described above, the progress of the interface crystallization is delayed, and the problem of the S / N reduction caused by the interface crystallization is reduced or eliminated. It is an object of the present invention to provide an image recording medium that can be used and a method for manufacturing the same.

  It is another object of the present invention to provide an image recording medium that can further reduce / eliminate the problem of S / N reduction due to interface crystallization and improve sensitivity to reading light, and a method for manufacturing the same. It is.

  The first image recording medium of the present invention comprises a transparent oxide film made of, for example, ITO or the like having transparency to a reading electromagnetic wave on a support having transparency to the reading electromagnetic wave. Occurs in one electrode layer (reading light side electrode layer), a reading photoconductive layer having a-Se as a main component and exhibiting conductivity when irradiated with a reading electromagnetic wave, and a recording photoconductive layer A power storage unit for accumulating latent image polar charges, a recording photoconductive layer that exhibits conductivity when irradiated with a recording electromagnetic wave, and a second electrode layer (recording light side) that is transparent to the recording electromagnetic wave In the image recording medium in which the electrode layer is laminated in this order, the a-Se interface crystallization is performed between the first electrode layer and the reading photoconductive layer and is permeable to reading electromagnetic waves. It is characterized by having a suppression layer to suppress That.

  In addition to the layer that suppresses interface crystallization, this suppression layer suppresses the direct injection of charges from the first electrode layer, and the first electrode layer and the read photoconductive layer. It is preferable that the first electrode layer and the reading photoconductive layer have a close-contacting and strengthening property while buffering the thermal stress due to the difference in thermal expansion coefficient.

  Here, in the case where the electrode of the first electrode layer is a stripe electrode formed by arranging a large number of linear electrodes in a direction perpendicular to the longitudinal direction, the suppression layer includes an upper surface and a side surface of each linear electrode. It is desirable to be provided continuously over the entire area.

  The “upper surface” means the surface on the reading photoconductive layer side. The “side surface” means two side surfaces extending in the longitudinal direction of the linear electrode. Thereby, the whole surface of each linear electrode will be covered with the suppression layer.

  In addition, from the viewpoint of suppressing interfacial crystallization, it is sufficient to cover the entire surface of each linear electrode with a suppression layer as described above, but from the viewpoint of ease of manufacture, the upper surface of the support between the linear electrodes is sufficient. Further, a suppression layer may be formed, and in this case, the suppression layer is continuously provided over the upper surface and the side surface of each linear electrode and the upper surface of the support.

  Specifically, the suppression layer preferably functions as a layer that suppresses interface crystallization while having the above-described permeability and blocking performance. For this purpose, the suppression layer forming material is made transparent and Insulating organic polymer materials such as polyamide, polyimide, polyester, polyvinyl butyral, polyvinyl pyrrolidone, polyurethane, polymethyl methacrylate, polycarbonate, etc., or mixed films composed of organic binders and low-molecular organic materials, etc. with good blocking performance and elasticity The organic thin film material is desirable.

  The thickness of the suppression layer is preferably about 0.05 to 5 μm, but in terms of thermal stress buffering, the range of 0.1 to 5 μm is preferable, but for good blocking performance without an afterimage, The range of 0.05-0.5 micrometer is preferable, and it is desirable to set it as the range of 0.1-0.5 micrometer on balance of both.

  Note that the first image recording medium only needs to have the above layers stacked in the above order. For example, other layers such as a charge transport layer described later may be stacked between the above layers.

  The second image recording medium of the present invention comprises a first electrode layer (reading light side electrode layer) having transparency to a reading electromagnetic wave on a support having transparency to the reading electromagnetic wave. A photoconductive layer for reading that exhibits conductivity by being irradiated with an electromagnetic wave for reading, the main component of which is a-Se, and a power storage unit that accumulates latent image polar charges generated in the photoconductive layer for recording, A recording photoconductive layer that exhibits conductivity when irradiated with a recording electromagnetic wave and a second electrode layer (recording light side electrode layer) that is transparent to the recording electromagnetic wave are laminated in this order. The image recording medium is characterized in that a substance that suppresses interfacial crystallization of a-Se is doped on the entire reading photoconductive layer or on the interface between the reading photoconductive layer and the first electrode layer. It is what.

  Here, when the interface in the photoconductive layer for reading is doped with a substance that suppresses interface crystallization, a thin layer that suppresses interface crystallization is substantially located at a position closest to the incident surface of the reading electromagnetic wave. It will be provided.

As the substance that suppresses the interfacial crystallization of a-Se, for example, As (arsenic) is preferable, and the doping amount is preferably 0.5 to 40 atom%, more preferably 5 to 40 atom%. The reason why the doping amount is in such a range is that if the As doping amount is small, the effect of preventing the Se crystallization at the interface is small, and conversely if the As doping amount exceeds 40%, a crystal different from Se crystallization is obtained. This is because there is an adverse effect such as crystallization, for example, As ₂ Se ₃ crystallization is likely to occur.

  If the thickness of the reading photoconductive layer is 0.05 to 0.5 μm, even if the entire reading photoconductive layer is doped with As by about 0.5 to 40 atom%, the reading response is greatly affected. Not give. When the thickness of the reading photoconductive layer is more than this, it is preferable to dope about 0.5 to 40 atom% only at the interface between the first electrode layer and the electrode in the reading photoconductive layer.

  In addition, hole or electron traps increase due to As doping. As will be described later, this increases the persistence of the interface photo-fatigue effect caused by pre-exposure, which may be advantageous for stabilization of offset noise.

In this case, the increased amount of hole traps or electron traps and the balance thereof can be changed depending on the doping amount of As. The hole trap increases at about 5 atom%, but the electron trap becomes dominant when the As concentration further increases, and the electron trap becomes closer to the property of a-As ₂ Se ₃ when the As doping amount is around 40 atom%. Many electrons cannot move and only holes can move. These As doping amounts may be adjusted according to the material of the first electrode layer, the material of the blocking layer provided between the first electrode layer and the reading photoconductive layer, and the like.

  Moreover, if Cl is doped to about 1 to 1000 ppm (atom base; the same applies hereinafter) in addition to As, electron traps can be increased. Moreover, if Na is doped with about 1 to 1000 ppm in addition to As, hole traps can be increased. These additional doping materials and amounts may be adjusted according to the electrode material of the first electrode layer, the material of the blocking layer provided between the first electrode layer and the reading photoconductive layer, and the like.

  The production method of the present invention is a method for producing an image recording medium having the above-described configuration, in which the electrode of the first electrode layer is a stripe electrode and has the suppression layer. It is formed by applying a suppression layer forming material in the longitudinal direction of the electrode.

  Here, when applying the suppression layer forming material in the longitudinal direction of the linear electrode, after forming the stripe electrode on a support such as glass or organic polymer, for example, dip method, spray method, bar coating method, screen A coating method or the like may be used. In particular, in the dip method, it is only necessary to repeat the operation of impregnating and pulling up a support having a stripe electrode formed in a solvent, and a large size can be manufactured relatively easily.

  In the second image recording medium, it is only necessary that the respective layers are laminated in the above order. For example, other layers such as a charge transport layer described later may be laminated between the respective layers.

  The third image recording medium of the present invention comprises a support having transparency to reading electromagnetic waves, a first electrode layer having transparency to reading electromagnetic waves, and a-Se as a main component. A reading photoconductive layer that exhibits conductivity by being irradiated with a reading electromagnetic wave, a power storage unit that accumulates a latent image polarity charge generated in the recording photoconductive layer, and a recording electromagnetic wave. In an image recording medium in which a recording photoconductive layer exhibiting conductivity and a second electrode layer having transparency to a recording electromagnetic wave are laminated in this order, the first electrode layer and the reading photoconductive layer Between the first electrode layer and the first electrode layer, and a blocking property against injection of the charge charged in the first electrode layer into the reading photoconductive layer, and a-Se interface crystallization. Suppressing suppression layer is provided, and the entire photoconductive layer for reading In addition, at the interface between the reading photoconductive layer and the suppression layer, a substance that suppresses interface crystallization of a-Se and a charge trap of the opposite polarity to the charge charged in the first electrode layer are increased and the same polarity. It is characterized in that it is doped with a substance that reduces the trap of electric charges.

  Here, the preferable form of the suppression layer of the third image recording medium is the same as that of the suppression layer in the first image recording medium, and the manufacturing method. The suppression layer in the third image recording medium suppresses a-Se interfacial crystallization as well as the suppression layer in the first image recording medium, and charges the first electrode layer to the reading photoconductive layer. Has blocking performance against injection. Having this blocking performance prevents the charge from moving from the reading light side electrode layer to the space charge layer formed at the interface with the blocking layer of the reading photoconductive layer to be described later. It has the ability to form a stable space charge layer at the interface with the blocking layer.

  In addition, a substance that suppresses interfacial crystallization of a-Se and a charge having a polarity opposite to that of the first electrode layer are formed on the entire reading photoconductive layer or on the interface with the suppressing layer of the reading photoconductive layer. When doped with a substance that increases traps and decreases charge traps of the same polarity, in addition to performing the same function as the second image recording medium, the first electrode layer has positive charges, When negative charge is charged in the two-electrode layer, a negative space charge layer is formed on the whole of the reading photoconductive layer or at the interface with the suppression layer, and the negative charge on the first electrode layer and second When a positive charge is charged on the electrode layer, it also functions to form a positive space charge layer on the entire reading photoconductive layer or on the interface with the suppression layer.

  Moreover, As can be used as a substance which suppresses the said interface crystallization, It is preferable to dope 3-40 atom%.

  In addition, when the charge charged on the first electrode layer is a positive charge, as a substance that increases traps of charges having the opposite polarity to those charged on the first electrode layer and decreases traps of charges of the same polarity. Cl can be used, and it is preferably doped with 1 to 1000 ppm.

  In addition, when the charge charged on the first electrode layer is a negative charge, the substance increases the traps of charges having the opposite polarity to those charged on the first electrode layer and decreases the traps of charges of the same polarity. Na can be used, and it is preferable to dope 1 to 1000 ppm.

  The thickness of the doped region is preferably 0.01 to 0.1 μm.

  Here, the “doped region” means a substance that suppresses the interface crystallization of a-Se and a trap of charges having a polarity opposite to that of the charge charged in the first electrode layer, and a charge of the same polarity. It means a region where both substances that reduce traps exist.

  The wavelength of the electromagnetic wave for reading is preferably 350 to 550 nm.

  Note that the third image recording medium only needs to have the above layers stacked in the above order, and for example, other layers such as a charge transport layer described later may be stacked between the above layers.

  According to the first image recording medium of the present invention, the suppression layer that suppresses the interface crystallization of a-Se is provided between the first electrode layer and the reading photoconductive layer. Since there is a suppression layer made of an organic thin film or the like at the interface between the material and a-Se, direct contact between the electrode material and a-Se can be prevented, and a chemical change of Se at the interface is prevented. The effect of preventing the conversion is obtained. Therefore, charge injection from the electrode due to interface crystallization does not increase, and the problem of S / N reduction can be solved.

  In addition, the suppression layer functions as a blocking layer to prevent a decrease in S / N due to direct injection from the electrode, or relieves thermal stress between the reading photoconductive layer and the reading light side electrode layer. It can function as a buffer layer so that thermal stress does not cause structural damage problems such as tearing of the reading photoconductive layer, cracking of the support, or physical separation of the two. .

  Even when the electrode of the first electrode layer is a stripe electrode, if the suppression layer is formed continuously over the upper and side surfaces of the linear electrode, the entire surface of each linear electrode is suppressed. As described above, it is possible to reliably prevent interface crystallization.

  In addition, a thin film that reliably covers the entire surface of each linear electrode can be formed by using a simple film forming method in which an organic polymer material or the like is applied in the longitudinal direction of the linear electrode.

  On the other hand, according to the second image recording medium of the present invention, since the reading photoconductive layer is doped with the substance that suppresses the interface crystallization of a-Se, the reading photoconductive layer has a first electrode layer. The effect of preventing the chemical change of Se at the interface and preventing the crystallization of the interface can be obtained, and the problem of S / N reduction due to the change in local photoconductive characteristics can be solved. In addition, when the interface between the reading photoconductive layer and the electrode of the first electrode layer is doped with a substance that suppresses the interface crystallization of a-Se, the interface crystallization is performed on the most incident side of the reading electromagnetic wave. This is substantially equivalent to the provision of a thin layer that suppresses the above, and the same effect as described above can be obtained.

  In general, the doping increases hole or electron traps at the interface and lowers the original function of the photoconductive layer. However, the increase in the traps can increase the durability of the photofatigue effect. Therefore, as an additional effect, it may be convenient to stabilize the offset noise. In addition to As, it is possible to adjust the durability of the light fatigue effect to a convenient state by doping about 1 to 1000 ppm of Cl or Na.

  Further, according to the third image recording medium of the present invention, the charge which is transmissive to the electromagnetic wave for reading between the first electrode layer and the reading photoconductive layer and is charged to the first electrode layer. Is provided with a suppression layer that has blocking performance against injection into the reading photoconductive layer and suppresses interface crystallization of a-Se, and the entire reading photoconductive layer or the suppression layer of the reading photoconductive layer A material that suppresses the interface crystallization of a-Se and a substance that increases traps of charges opposite in polarity to those charged in the first electrode layer and decreases traps of charges of the same polarity are doped at the interface of Therefore, the same effects as those of the first and second image recording media can be obtained, and the electric field strength can be increased by forming a negative or positive space charge layer in the reading photoconductive layer. Improve charge pair generation efficiency Since bets can, it is possible to improve the sensitivity to reading light.

  In addition, when As is used as a substance that suppresses interface crystallization and is doped 3 to 40 atom%, the space charge layer can be formed more efficiently without degrading the original function of the photoconductive layer. Thus, the generation efficiency of charge pairs can be further improved.

  In addition, when the charge charged in the first electrode layer is a positive charge, As is used as a substance that suppresses interface crystallization, increasing the number of traps of charges opposite to the charge charged in the first electrode layer, and When Cl or Na is used as a substance that reduces charge traps of the same polarity and Cl or Na is doped by 1 to 1000 ppm, the negative or positive is more efficiently performed without deteriorating the original function of the photoconductive layer. Therefore, the generation efficiency of charge pairs can be further improved.

  In addition, a region doped with a substance that suppresses the interface crystallization of a-Se and a substance that increases traps of charges opposite in polarity to charges charged in the first electrode layer and decreases traps of charges of the same polarity is doped. When the thickness is set to 0.01 to 0.1 μm, the thickness of the doped region is less than or equal to the absorption depth of the reading light with respect to the reading photoconductive layer. The generation efficiency can be improved.

Further, when the wavelength of the electromagnetic wave for reading is set to 350 to 550 nm, the generation efficiency of charge pairs can be improved more efficiently than the above.

A perspective view (A) and a partial cross-sectional view (B) of the electrostatic recording body according to the first embodiment The figure explaining dope when the electrode of the reading light side electrode layer is a stripe electrode 1 is a schematic view integrally showing an electrostatic latent image recording apparatus using an electrostatic recording body and an electrostatic latent image reading apparatus according to a first embodiment. Perspective view (A) and partial sectional view (B) of an electrostatic recording body according to the second embodiment Perspective view (A) and partial sectional view (B) of an electrostatic recording body according to the third embodiment The figure which showed an example of the manufacturing method of the electrostatic recording body by 3rd Embodiment Sectional views (A) and (B) showing an intermediate stage of production of an electrostatic recording body according to the third embodiment and sectional views (C) showing an intermediate stage of production by another method Schematic diagram integrally representing an electrostatic latent image recording apparatus and an electrostatic latent image reading apparatus using an electrostatic recording body according to a third embodiment. The figure explaining the recording process using the electrostatic recording body by 3rd Embodiment Perspective view (A) and partial sectional view (B) of an electrostatic recording body according to the fourth embodiment The figure explaining the recording process and reading process using the electrostatic recording body by 4th Embodiment The figure which shows the relationship between the electric field strength formed in the electrostatic recording body by 4th Embodiment, and the depth from the incident surface of reading light

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view (A) showing an outline of a first embodiment of an electrostatic recording body which is an embodiment of the image recording medium of the present invention, and a partial sectional view (B) thereof.

  The electrostatic recording body 10 according to the first embodiment includes a recording light side electrode layer 1 that is transmissive to recording light (for example, radiation such as X-rays), and recording that has passed through the recording light side electrode layer 1. The recording photoconductive layer 2 that exhibits conductivity when irradiated with light and the charge (latent image polar charge) charged on the recording light side electrode layer 1 act as an approximately insulator, and the latent image A charge transport layer 3 that acts as a substantially conductive material with respect to a charge of opposite polarity to the image polarity charge (transport polarity charge), and exhibits conductivity when irradiated with reading light (for example, blue light having a wavelength of 550 nm or less). The reading photoconductive layer 4, the reading light side electrode layer 5 having transparency to the reading light, and the support 8 having transparency to the reading light are arranged in this order. At the interface between the recording photoconductive layer 2 and the charge transport layer 3, a power storage unit 23 for accumulating latent image polar charges generated in the recording photoconductive layer 2 is formed. In each of the following embodiments, the recording light side electrode layer 1 is charged with a negative charge, and the reading light side electrode layer 5 is charged with a positive charge, so that the interface between the recording photoconductive layer 2 and the charge transport layer 3 is formed. The storage unit 23 to be formed accumulates negative charges as latent image polar charges, and causes the charge transport layer 3 to function as a transport polar charge having a polarity opposite to that of the negative charge as the latent image polar charges. An electrostatic recording medium that functions as a so-called hole transport layer having a higher positive charge mobility will be described.

  When the electrostatic recording body 10 is manufactured, the reading light side electrode layer 5 is formed (laminated) on the support 8 in the reverse order, and then the reading photoconductive layer is sequentially formed. 4. The charge transport layer 3, the recording photoconductive layer 2, and the recording light side electrode layer 1 are formed (laminated).

  In addition, the size (area) of the electrostatic recording body 10 is, for example, 20 × 20 cm or more, and particularly in the case of chest X-ray imaging, the effective size is about 43 × 43 cm.

In addition to being transparent to the reading light, the support 8 can be deformed with respect to environmental temperature changes, and the coefficient of thermal expansion of the support 8 is the heat of the substance of the reading photoconductive layer 4. A substance having a relatively close thermal expansion coefficient is used within one to several times the expansion coefficient, preferably both. As will be described later, in this embodiment, a-Se (amorphous selenium) is used as the reading photoconductive layer 4, so that the thermal expansion coefficient of Se is 3.68 × 10 ⁻⁵ / K (40 ° C.). In consideration of the thermal expansion coefficient, the coefficient of thermal expansion is 1.0 to 10.0 × 10 ⁻⁵ / K (40 ° C.), more preferably 1.2 to 6.2 × 10 ⁻⁵ / K (40 ° C.), and further preferably Uses a material that is 2.2-5.2 × 10 ⁻⁵ / K (40 ° C.). An organic polymer material can be used as a substance that can be deformed and has a coefficient of thermal expansion in this range.

Specific examples of the organic polymer material include polycarbonate having a thermal expansion coefficient of 7.0 × 10 ⁻⁵ / K (40 ° C.) and a thermal expansion coefficient of 5.0 × 10 ⁻⁵ / K (40 ° C.). Polymethyl methacrylate (PMMA) or the like can be used.

  As a result, the thermal expansion of the support 8 serving as the substrate and the photoconductive layer 4 for reading (Se film) can be matched, and a large temperature cycle can be obtained in a special environment, for example, during ship transportation in a cold climate. However, the thermal stress is generated at the interface between the support 8 and the reading photoconductive layer 4 so that the both are physically separated, the reading photoconductive layer 4 (Se film) is broken, or the support 8 is broken. The problem of destruction due to thermal expansion difference, such as cracking, does not occur. Furthermore, the organic polymer material has a merit that it is more resistant to impact than the glass substrate.

The recording light side electrode layer 1 and the reading light side electrode layer 5 only have to be transmissive to the recording light or the reading light, respectively. For example, both the Nesa film (SnO ₂ ), ITO (Indium Tin) Oxide), IDIXO (Idemitsu Indium X-metal Oxide; Idemitsu Kosan Co., Ltd.), which is an amorphous light-transmitting oxide film, can be used with a thickness of 50 to 200 nm. Note that when X-rays are used as the recording light and the X-rays are irradiated from the recording light side electrode layer 1 side to record an image, the recording light side electrode layer 1 does not need to be transparent to visible light. For example, 100 nm thick Al or Au can be used.

  The electrode layers 1 and 5 may be composed entirely of electrodes (so-called flat plate electrodes) as in the present embodiment. For example, the linear electrodes are orthogonal to the longitudinal direction. You may have a stripe electrode arranged in the direction. In the latter case, when an insulator is arranged between each linear electrode, the electrode layer is constituted by the linear electrode and the insulator, while insulating as in the third embodiment to be described later. In the case where the next layer is immediately laminated without any object being disposed, the electrode layer is constituted by only the stripe electrodes.

The recording photoconductive layer 2 only needs to exhibit conductivity when irradiated with recording light. For example, lead (II) oxide such as a-Se, PbO, PbI ₂ or lead iodide (II ), Bi ₁₂ (Ge, Si) O ₂₀ , Bi ₂ I ₃ / Organic polymer nanocomposite, etc., a photoconductive substance containing at least one of the main components is suitable. On the other hand, a-Se, which is excellent in terms of relatively high quantum efficiency and high dark resistance, is used.

  The thickness of the recording photoconductive layer 2 containing a-Se as a main component is preferably 50 μm or more and 1000 μm or less so that the recording light can be sufficiently absorbed.

The charge transport layer 3, and the mobility of the negative charges charged on the recording light side electrode layer 1, as good as the difference in the mobility of positive charge which becomes the opposite polarity is large (e.g., 10 ² or more, preferably 10 ³ Above), poly N-vinylcarbazole (PVK), N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (TPD) A semiconductor substance such as organic compounds such as a discotic liquid crystal, a TPD polymer (polycarbonate, polystyrene, PUK) dispersion, or a-Se doped with 10 to 200 ppm of Cl is suitable. In particular, an organic compound (PVK, TPD, discotic liquid crystal, etc.) is preferable because it has a light insensitivity, and since the dielectric constant is generally small, the capacitance of the charge transport layer 3 and the reading photoconductive layer 4 is reduced, and thus reading is performed. The signal extraction efficiency can be increased. Note that “having light insensitivity” means that the material hardly exhibits conductivity even when irradiated with recording light or reading light.

  Also, for example, if the charge mobility in the vertical direction of the film thickness is larger than the charge mobility in the horizontal direction of the film thickness, the transport polarity charge can move at high speed in the thickness direction and hardly move in the horizontal direction. Since the charge transport layer can be formed, the sharpness can be improved. Specific materials include discotic liquid crystals, hexapentyloxytriphenylene (hexapentyloxytriphenylene (see Physical Review LETTERS 70.4, 1933)), and discotic liquid crystal groups containing a π-conjugated condensed ring or transition metal in the central core (EKISHO VOL No .1 1997 P55) is suitable.

  Further, the charge transport layer 3 is a first charge transport made of a material having a property of acting substantially as an insulator for the charge charged on the recording photoconductive layer 2, that is, the charge having the same polarity as the latent image polar charge. Layer and at least a second charge transport layer made of a material having a property of acting as a substantially conductive material with respect to a charge opposite in polarity to the latent image polar charge, that is, a transport polar charge. If the stacked hole transport layer is laminated so that the second charge transport layer is on the reading photoconductive layer 4 side on the conductive layer 2 side, the second charge transport layer has high-speed transport property of transport polar charge. In addition, since the first charge transport layer can be provided with a strong insulating property against the latent image polar charge, it should be ideal as a charge transport layer excellent in afterimage and read response speed. Can do. Specifically, the first charge transport layer is made of at least one of PVK or TPD, which is an organic substance, so that the second charge transport layer is thicker than the first charge transport layer. A layer having a thickness of 1 μm may be used, and the second charge transport layer may be an a-Se layer having a thickness of 5 to 30 μm doped with 10 to 200 ppm of Cl.

  Further, when comparing the layer made of PVK and the layer made of TPD, the layer made of PVK has the property of acting as an insulator for charges having the same polarity as the latent image polar charge (negative polarity in the above example). The layer made of TPD and the layer made of TPD are stronger than the layer made of PVK because the layer made of TPD is stronger than the layer made of PVK in that it has a property of acting almost as a conductor for the transport polar charge (positive polarity in the above example) The charge transport layer may be laminated so that the layer made of TPD is on the reading photoconductive layer side and the layer made of PVK is on the recording photoconductive layer side.

  It should be noted that the layer is not limited to two layers, and may be composed of a plurality of layers. In this case, when each layer is stacked, the same polarity as the latent image polarity charge is obtained when the above properties of each layer are compared. The layer that has a relatively strong property of acting as an insulator for the charge of the recording layer is the photoconductive layer for recording, and the layer that has a relatively strong property of acting as a conductor for the transport polar charge is a photoconductive layer for reading. What is necessary is just to laminate | stack so that it may become a layer side.

  The reading photoconductive layer 4 may be any material that exhibits conductivity when irradiated with reading light. For example, a-Se, Se-Te, Se-As-Te, metal-free phthalocyanine, metal phthalocyanine, A photoconductive substance mainly composed of at least one of MgPc (Magnesium phtalocyanine), VoPc (phase II of Vanadyl phthalocyanine), CuPc (Cupper phtalocyanine) and the like is preferable.

Also, those having high sensitivity to electromagnetic waves having a wavelength in the near ultraviolet to blue region (300 to 550 nm) and having low sensitivity to electromagnetic waves having a wavelength in the red region (700 nm or more), specifically , A-Se, PbI ₂ , Bi ₁₂ (Ge, Si) O ₂₀ , perylene bisimide (R = n-propyl), and perylene bisimide (R = n-neopentyl) as a main component If a conductive material is used, the reading photoconductive layer 4 having a large band gap and a small generation of dark current due to heat can be obtained. Therefore, at the time of reading, an electromagnetic wave having a wavelength in the near ultraviolet to blue region is scanned and exposed. By doing so, noise due to dark current can be reduced.

  The total thickness of the charge transport layer 3 and the reading photoconductive layer 4 is desirably ½ or less of the thickness of the recording photoconductive layer 2, and the thinner the thickness (for example, 1 / 10 or less, or even 1/20 or less, etc.) Response at the time of reading is improved.

  In particular, a-Se having a thickness of 0.05 to 0.5 μm is preferable because dark resistance becomes very high. From the above, in this embodiment, the reading photoconductive layer 4 is a 0.05 to 0.5 μm thick layer containing a-Se as a main component.

  In addition, the 5-30 μm-thick second hole transport layer made of “a-Se doped with 10 to 200 ppm of Cl” in the charge transport layer 3 is replaced with 5-30 μm-thick a-Se, and the read photoconductivity A configuration that also serves as the layer 4 may be employed. Further, in the case of this configuration, the production of the electrostatic recording body 10 becomes relatively simple.

  Here, as described above, an amorphous selenium film has a problem in that interface crystallization proceeds at the interface with other substances in the deposition process during film formation. Also in the electrostatic recording body 10 of the present invention, the reading photoconductive layer 4 is formed after forming the reading light side electrode layer 5 on the support 8. Interfacial crystallization proceeds at the interface between the material and a-Se, and charge injection from the electrode increases, which may cause a problem that S / N decreases. When a transparent oxide film, particularly ITO, is used as the electrode material, interface crystallization at the interface between the electrode material and a-Se proceeds remarkably, and the S / N reduction becomes significant.

  However, in the electrostatic recording body 10 of the present invention, the crystallization of the a-Se forming the reading photoconductive layer 4 is suppressed at the interface between the reading photoconductive layer 4 and the electrode of the reading light side electrode layer 5. A thin layer that substantially suppresses interface crystallization is formed by the doping.

In the present embodiment, As (arsenic) is used as a substance that suppresses interface crystallization, and the doping amount is about 0.5 to 40% atom. The reason why the doping amount is in such a range is that if the As doping amount is small, the effect of preventing the Se crystallization at the interface is small, and conversely if the As doping amount exceeds 40%, a crystal different from Se crystallization is obtained. This is because there is an adverse effect such as crystallization, for example, As ₂ Se ₃ crystallization is likely to occur. In addition to As, other substances may be doped as long as they have the property of suppressing interface crystallization.

  If the thickness of the reading photoconductive layer 4 is set to 0.05 to 0.5 μm, the dark resistance is high, and the entire reading photoconductive layer 4 is doped with about 0.5 to 40 atom% As. The read response is not greatly affected. On the other hand, when the thickness of the reading photoconductive layer 4 is more than this, it is preferable to dope only at the interface with the reading light side electrode layer 5 in the reading photoconductive layer 4.

  As shown in FIG. 2, in the case where the electrode of the reading light side electrode layer 5 is a striped electrode 6 in which a large number of elements (linear electrodes) 6a are arranged, the reading photoconductive layer 4 and each electrode As is doped on the interface extending over the upper surface and side surface of the element 6a to ensure prevention of interface crystallization. Note that there may be a slight difference in the doping amount at the step portion, and in this case, the doping amount at the interface on the upper surface of the element 6a may be about 0.5 to 40 atom%.

  By the way, when the electrode of the reading light side electrode layer 5 and a-Se are in direct contact with each other, a barrier electric field is formed at the interface between them, and even in a region where there is no recording light irradiation (radiation dose is 0 mR region) It is also known that a current flows due to irradiation of reading light, so-called photovoltaic noise is generated, and offset noise is generated.

  In order to suppress this photovoltaic noise, the applicant of the present application disclosed in Japanese Patent Application No. 11-194546 the pre-exposure light on the reading photoconductive layer 4 with the electrodes of both electrode layers 1 and 5 being at the same potential. Pre-exposure light is emitted by irradiating recording light with a recording voltage applied between both electrodes and performing recording of an electrostatic latent image. A photo-fatigue state (trap accumulation state) is temporarily formed at the light incident interface (electron-hole pair formation region) that is the interface between the read photoconductive layer 4 and the read light side electrode layer 5 and read. A method has been proposed in which photovoltaic noise that may occur when light is irradiated is reduced and stabilized by the light fatigue state.

  As described above, the interface between the reading photoconductive layer 4 and the reading light side electrode layer 5 (specifically, the electrode) in the electrostatic recording body 10 of the present embodiment, that is, the light incident interface is doped with As. In addition, due to the doping, hole and electron traps increase at the light incident interface. Here, the pre-exposure is intended to suppress photovoltaic noise by forming a photo-fatigue state (trap accumulation state) at the interface exposed to light. If this is increased, the light fatigue effect of the interface caused by the pre-exposure can be maintained, which is rather convenient for stabilizing the offset noise. In addition, the part which is not doped bears carrier travelability.

  However, it is difficult to control the increase in the number of traps of holes and electrons due to As doping, and it is not easy to maintain the light fatigue effect in a convenient state only by As doping. However, in this case, in addition to As, for example, if Cl is doped by about 1 to 1000 ppm, electron traps can be increased, and if Na is doped by about 1 to 1000 ppm, hole traps can be increased. By controlling these added dope materials and amounts, the light fatigue effect can be maintained in a convenient state. Note that how much of Cl or Na is doped may be adjusted according to the electrode material of the reading light side electrode layer 5. As will be described later, when a blocking layer is provided between the reading light side electrode layer 5 and the reading photoconductive layer 4, it may be adjusted according to the material of the blocking layer.

  Note that an amorphous selenium film is likely to be crystallized with time, and the characteristics, particularly the dark resistance characteristics, deteriorate, that is, the so-called bulk crystallization problem. It is well known that it appears prominently in the case of a-Se, and that it progresses faster at higher temperatures.

  Therefore, when a large amount of undoped pure a-Se is used as the recording photoconductive layer 2, the reading photoconductive layer 4, and the charge transport layer 3, the electrostatic recording body 10 has severe operating temperature conditions and lifetime. The problem of being restricted also arises.

On the other hand, as is well known, when a predetermined substance, particularly As, is doped to prevent bulk crystallization, the progress of the bulk crystallization can be slowed. However, when a large amount of As is doped into a-Se, for example, As ₂ Se ₃ crystallization is likely to occur, and therefore, a small amount of doping of about 0.1 to 0.5 atom%, more preferably 0.33 atom is preferable. %. This dope amount is less than the dope amount for suppressing the above-mentioned interface crystallization, and is preferably at least 1/10 or less.

  Further, in order to positively prevent the above-described adverse effects, a small amount of 10 to 50 ppm of Cl is doped simultaneously with As. At this time, as described in the document “Time-of-Flight Study of Compensation Mechanism in a-Se Alloys” (JOURNAL OF IMAGING SCIENCE AND TECHNOLOGY / Vol.41, Number 2 Mar./Apr. 1997) Addition of about 30 to 40 ppm of Cl at the same time as doping 0.33 atom% As with respect to a-Se makes it possible to ideally compensate for the increase in hole traps due to As doping by Cl doping. When doping, it is desirable to maintain the ratio of As to 0.33 atom% and Cl to 30 to 40 ppm.

  By applying such a small amount of doping to pure a-Se to the recording photoconductive layer 2 and the reading photoconductive layer 4 containing a-Se as a main component, no significant adverse effects are caused. S / N is good, can withstand use at a relatively high temperature, and an image recording medium having a long life can be realized. In addition, As doping that suppresses the above-described interface crystallization is performed on the interface between the reading photoconductive layer 4 and the reading light side electrode layer 5, and the As doping that suppresses bulk crystallization is performed on the reading photoconductive layer 4. It can also be done. In this case, only the doping amount is different between the interface and the inside of the reading photoconductive layer 4. Further, when As doping is performed at 0.5 atom%, which is the critical point for both crystallization of the bulk and the interface, crystallization of both the bulk and the interface can be suppressed at the interface.

  On the other hand, when the charge transport layer 3 functions as a hole transport layer, if As is used as a doping material, the function as the hole transport layer decreases due to an increase in hole traps, and in some cases, the function is lost. It will be. Therefore, it is not preferable that the charge transport layer 3 functioning as a hole transport layer is simply doped with As alone to prevent bulk crystallization. On the other hand, as described above, the increase in hole traps due to As doping can be compensated by Cl doping, so that the charge transport layer 3 made of a-Se doped with 10 to 200 ppm of Cl that functions as a hole transport layer can be obtained. In order to prevent bulk crystallization, doping with 0.1 to 0.5 atom% As and 20 to 250 ppm Cl delays the progress of bulk crystallization without deteriorating the function as a hole transport layer. Can do. Even in this case, when the ratio of As is 0.33 atom% and Cl is maintained at 30 to 40 ppm, the function as the hole transport layer is hardly deteriorated.

  Next, a basic method for recording image information as an electrostatic latent image on the electrostatic recording body 10 having the above-described structure and reading the recorded electrostatic latent image will be briefly described. FIG. 3 is a schematic diagram showing an electrostatic latent image recording apparatus using an electrostatic recording body 10 and an electrostatic latent image reading apparatus in an integrated manner for convenience, and a recording / reading system combining the recording apparatus and the reading apparatus. That's it. In the figure, the support 8 is omitted.

  This recording / reading system includes an electrostatic recording body 10, a recording light irradiation means 90, a connection means S1, a power source 70, a current detection circuit 80 including a connection means S2 and a detection amplifier 81, and a reading light scanning means 92. The electrostatic latent image recording device portion includes an electrostatic recording body 10, a power source 70, recording light irradiation means 90, and connection means S1, and the electrostatic latent image reading device portion includes an electrostatic recording body 10 and a current detection circuit. 80 and connection means S2.

  The detection amplifier 81 is a so-called current-voltage conversion circuit including an operational amplifier 81a and a feedback resistor 81b. Note that the detection amplifier 81 is not limited to this, and may have a charge amplifier configuration, for example.

  The recording light side electrode layer 1 of the electrostatic recording body 10 is connected to the negative electrode of the power source 70 via the connection means S1, and is also connected to one end (output side) of the connection means S2. One of the other ends of the connecting means S2 is connected to the inverting input terminal (−) of the operational amplifier 81a, the reading light side electrode layer 5 of the electrostatic recording body 10, the positive electrode of the power supply 70, the other end of the other end of the connecting means S2, and the operational amplifier. The non-inverting input terminal (+) of 81a is grounded.

  A subject 9 is disposed on the upper surface of the recording light side electrode layer 1, and the subject 9 has a portion 9a that is transparent to the radiation L1 and a blocking portion (light-shielding portion) 9b that is not transparent. The recording light irradiation means 90 uniformly irradiates the subject 9 with radiation L1 such as X-rays, and the reading light scanning means 92 scans and exposes the reading light L2 such as laser light in the direction of the arrow in FIG. It is desirable that the reading light L2 has a beam shape converged to a small diameter.

  When recording an electrostatic latent image on the electrostatic recording body 10, first, the connecting means S2 is opened, the connecting means S1 is turned on, and the recording light side electrode layer 1 and the reading light side electrode layer 5 are interposed. A direct current voltage Ed from a power source 70 is applied to the recording light side electrode layer 1 and a negative charge is charged to the recording light side electrode layer 5 from the power source 70. Thereby, a parallel electric field (electric field) is formed between the recording light side electrode layers 1 and 5 in the electrostatic recording body 10.

  Next, the recording light irradiation means 90 uniformly radiates the radiation L1 toward the subject 9. The radiation L1 passes through the transmission part 9a of the subject 9, and further passes through the recording light side electrode layer 1. The recording photoconductive layer 2 receives this transmitted radiation L1 (the radiation from the subject 9 becomes recording light), and electrons (negative charge; latent image polar charge in this example) according to the dose (light quantity) of the radiation L1. ) And a hole (positive charge; transport polarity charge in this example) are generated, and become conductive.

  The positive charges generated in the recording photoconductive layer 2 move at high speed in the photoconductive layer 2 toward the recording light side electrode layer 1 and are recorded at the interface between the recording light side electrode layer 1 and the photoconductive layer 2. The light-side electrode layer 1 disappears due to charge recombination with the negative charge charged. On the other hand, the negative charges generated in the photoconductive layer 2 move in the photoconductive layer 2 toward the charge transport layer 3. Since the charge transport layer 3 acts as an insulator for the latent image polar charge (negative charge in this example) having the same polarity as the charge charged on the recording light side electrode layer 1, it moves in the photoconductive layer 2. The negative charge thus generated stops at the power storage unit 23 formed at the interface between the photoconductive layer 2 and the charge transport layer 3 and is accumulated at this interface (power storage unit 23). The amount of accumulated charge is determined by the amount of negative charge generated in the photoconductive layer 2, that is, the amount of radiation L1 transmitted through the subject 9. On the other hand, since the radiation L1 does not pass through the light shielding portion 9b of the subject 9, the portion corresponding to the lower portion of the light shielding portion 9b of the electrostatic recording body 10 does not change at all.

  In this way, by bombarding the subject 9 with the radiation L 1, charges corresponding to the subject image can be accumulated in the power storage unit 23 formed at the interface between the recording photoconductive layer 2 and the charge transport layer 3. become able to. The subject image carried by the accumulated latent image polarity charge is called an electrostatic latent image. As is clear from the above description, the configuration of the apparatus for recording an electrostatic latent image on the electrostatic recording body 10 according to the present invention is extremely simple, and the recording operation is also extremely simple.

  When reading the electrostatic latent image recorded in this way, the connecting means S1 is opened to stop the power supply, and the connecting means S2 is temporarily connected to the ground side, and both electrode layers 1 of the electrostatic recording body 10 are connected. , 5 are set to the same potential and the charge is rearranged, and then the connecting means S2 is connected to the detection amplifier 81 side.

  Next, the reading light scanning unit 92 scans the reading light side electrode layer 5 side of the electrostatic recording body 10 with the reading light L2. The reading light L2 passes through the reading light side electrode layer 5, and the reading photoconductive layer 4 irradiated with the reading light L2 exhibits conductivity according to the scanning. This is dependent on the fact that the recording photoconductive layer 2 is exposed to the radiation L1 to produce positive and negative charge pairs, and that the recording photoconductive layer 2 is irradiated with the reading light L2 to generate positive and negative charge pairs. To do.

  The reading photoconductive layer 4 and the charge transport are provided between the power storage unit 23 (interface between the recording photoconductive layer 2 and the charge transport layer 3) where the latent image polar charge is stored and the reading light side electrode layer 5. An electric field is formed according to the total thickness of the layer 3 and the amount of latent image polar charge. Here, since the charge transport layer 3 acts as a conductor for the transport polar charge (positive charge in this example), the positive charge generated in the reading photoconductive layer 4 is a latent image of the power storage unit 23. It rapidly moves in the charge transport layer 3 so as to be attracted by the polar charge, and is recombined with the latent image polar charge in the power storage unit 23 and disappears. On the other hand, the negative charge generated in the reading photoconductive layer 4 is recombined with the positive charge of the reading light side electrode layer 5 and disappears. The photoconductive layer 4 is scanned with a sufficient amount of light by the reading light L2, and all the electrostatic latent images carried by the latent image polar charges accumulated in the power storage unit 23 are extinguished by charge recombination. As described above, the disappearance of the charges accumulated in the electrostatic recording body 10 means that a current due to the movement of the charges flows in the electrostatic recording body 10. A current detection circuit 80 is connected to the electrostatic recording body 10, and an image signal is obtained by taking this current out and detecting it with a detection amplifier 81 (converting it into a voltage signal).

It should be noted that as the total thickness of the reading photoconductive layer 4 and the charge transport layer 3 (the sum of both thicknesses) is smaller than the thickness of the recording photoconductive layer 2, the movement of charges is rapidly increased. As a result, reading can be performed at high speed. Furthermore, if the mobility of the negative charge in the charge transport layer 3 is sufficiently smaller than the mobility of the positive charge (for example, 1/10 ³ or less), the storage property of the stored charge is improved and the storability of the electrostatic latent image is improved. It will be.

  Next, a second embodiment of the electrostatic recording body will be described. FIG. 4 is a perspective view (A) showing an outline of the electrostatic recording body of the second embodiment and a partial cross-sectional view (B) thereof.

  The electrostatic recording body 10 according to the second embodiment is transmissive to the reading light between the reading photoconductive layer 4 and the reading light side electrode layer 5 and has a reading light side electrode layer. 5 is different from that of the first embodiment in that a blocking layer 7 having blocking performance (having a barrier potential) against charge injection from the five electrodes is provided.

  When the blocking layer is not provided as in the first embodiment, a part of the charge (positive charge in this example) charged on the reading light side electrode layer 5 (positive electrode) is used for reading. Some are directly injected into the photoconductive layer 4, and the positive charge directly injected into the reading photoconductive layer 4 moves in the charge transport layer 3 to recombine with the accumulated charge (latent image polar charge). As a result, the accumulated charge disappears. The disappearance of the accumulated charge due to the charge recombination does not occur due to the irradiation of the reading light, and thus becomes a so-called noise component. On the other hand, as in the present embodiment, the blocking layer 7 made of an organic thin film is laminated between the reading light side electrode layer 5 and the reading photoconductive layer 4 so that the reading light side electrode layer 5 is positively charged. The charges are not injected into the reading photoconductive layer 4 due to the barrier potential, and noise due to direct injection of positive charges can be prevented.

  Here, as described above, the crystallization of the selenium film in the amorphous state proceeds at the interface with another metal. However, in the electrostatic recording body 10 of the second embodiment, the blocking layer 7 made of an organic thin film is provided between the reading light side electrode layer 5 and the reading photoconductive layer 4. 7 can function as a suppression layer that suppresses interface crystallization of a-Se, and prevents direct contact between the electrode material of the reading light side electrode layer 5 and the a-Se of the reading photoconductive layer 4. The effect of preventing the chemical change of Se at the interface and preventing the interface crystallization can be obtained. Therefore, charge injection from the electrode does not increase, and the problem of S / N reduction due to interface crystallization can be solved.

  In the present embodiment, an elastic material is used as the blocking layer 7, and the blocking layer 7 relieves thermal stress between the support 8 and the reading photoconductive layer 4 (hereinafter referred to as “blocking layer 7”). It also functions as a buffer layer (called heat stress buffer). The blocking layer 7 preferably functions as a layer that strengthens the adhesion between the read photoconductive layer 4 and the read light side electrode layer 5.

  When the blocking layer 7 is provided with a thermal stress buffering function, the thermal stress due to the thermal expansion difference between the read photoconductive layer 4 and the support 8 can be reduced by the mechanical stress buffering action of the blocking layer 7. Therefore, the material of the support 8 can be selected without considering the thermal expansion coefficient of the reading photoconductive layer 4. For example, even when glass or the like is used, a thermal stress buffering effect that alleviates the mismatch of thermal expansion between the glass substrate as the support 8 and the Se film as the reading photoconductive layer 4 occurs, and the first embodiment Similar to the configuration, the problem of destruction due to the difference in thermal expansion does not occur even in a special environment.

  Here, in order to allow the blocking layer 7 to function as a suppression layer that suppresses the interface crystallization of a-Se and also to function as a buffer layer that relieves thermal stress, for example, a layer of an organic thin film rich in elasticity is used. It is preferable. As this organic thin film, for example, polyamide (polyamide) or polyimide (polyimide) shown in US Pat. No. 4,535,468, polyester, polyvinyl butyral, polyvinyl pyrrolidone, polyurethane, polymethyl methacrylate, polycarbonate, etc., reading light ( For example, a thin film of an insulating organic polymer that is transparent to blue light and has good hole blocking performance can be used. It is also possible to use a thin layer of a mixed film consisting of an organic binder and a low molecular weight organic material such as about 0.3 percent to 3 percent by weight nigrosine.

  The film thickness of the organic thin film is preferably about 0.05 to 5 μm. However, in terms of thermal stress buffering, the range of 0.1 to 5 μm is preferable, but for good blocking performance without an afterimage, 0 is preferable. A range of 0.05 to 0.5 μm is preferable, and a range of 0.1 to 0.5 μm is preferable in terms of a balance between the two.

  Next, a third embodiment of the electrostatic recording body will be described. FIG. 5 is a perspective view (A) showing an outline of the electrostatic recording body of the third embodiment and a partial cross-sectional view (B) thereof. FIG. 6 is a diagram showing an example of a method for manufacturing the electrostatic recording member up to an intermediate stage.

  The electrostatic recording body 10 of the third embodiment is the same as that of the second embodiment described above, in which the electrodes of the reading light side electrode layer are arranged with a number of elements (linear electrodes) 6a arranged at a pixel pitch. The difference is that the stripe electrode 6 is formed. In this case, the insulating layer is not disposed between the elements 6a, and the blocking layer 7 as the next layer is immediately laminated, and the reading light side electrode layer 5 is constituted by only the stripe electrodes 6.

  The blocking layer 7 of the electrostatic recording body 10 according to the third embodiment can function as a suppression layer that suppresses a-Se interface crystallization, as in the second embodiment. The problem of S / N reduction due to interface crystallization can be solved.

  The purpose of using the read light side electrode layer 5 as the stripe electrode 6 is that, as will be described later, the structure noise can be corrected easily, the S / N of the image can be improved by reducing the capacitance, By localizing the electrostatic latent image corresponding to the stripe electrode, the electric field strength is increased to improve the reading efficiency and the S / N, or the parallel reading (mainly in the main scanning direction) is performed to reduce the reading time. For example, shortening.

  When manufacturing the electrostatic recording body 10 of the third embodiment, first, a transparent oxide film such as ITO or easy-to-etch IDIXO is formed on the support 8 with a predetermined thickness (for example, about 200 nm). ) To form the reading light side electrode layer 5 (see FIG. 6A).

  Then, after forming an ITO film or the like, a process such as photoetching is performed to form an element 6a to form a stripe electrode 6 (see FIG. 6B). According to this method, for example, a high-definition stripe pattern having a pixel pitch of about 50 to 200 μm suitable for medical use can be formed at low cost.

  It should be noted that IDIXO is a film that can be easily etched, and if this IDIXO is used as an electrode member that forms the element 6a, the possibility of melting the support 8 during the etching process is reduced, and the selection range of the support 8 is widened. .

  Next, a blocking layer forming material forming the blocking layer 7 that also functions as a buffer layer is applied in the longitudinal direction of the element 6a along the element 6a to form a predetermined thickness (for example, about 200 nm). To do. When the reading light side electrode layer 5 is planar as in the second embodiment, the application direction does not matter and can be applied using a method such as spin coating. In the embodiment, it is not preferable to use the spin coating.

  When the blocking layer 7 that also functions as a buffer layer against thermal stress is applied in the longitudinal direction of the element 6a to form a film, the stripe electrode 6 is formed on the support 8 and then, for example, a dip method (dippinng ), Spraying method (Spraying), bar coating method, screen coating method, etc., it is preferable to use a method in which members, nozzles, brushes, etc. are moved one-dimensionally and applied.

  FIG. 6C briefly shows an example of the dip method. In this dipping method, the material liquid 70 for the blocking layer 7 is filled in the container 40, and the member 11 having the stripe electrode 6 formed on the support 8 is placed in the liquid 70 along the longitudinal direction of the element 6a. It is a method of immersing and pulling up. Even if the size of the member 11, that is, the electrostatic recording body 10 is large, this method can be dealt with only by using the container 40 according to the size, and the film thickness can be adjusted by repeated impregnation and pulling, so that the large size can be freely set. There is an advantage that a film having a large thickness can be easily manufactured.

  FIG. 7A is a cross-sectional view showing a state in which the blocking layer 7 is formed by coating in the longitudinal direction of the element 6a. As shown in the drawing, the blocking layer 7 is continuously and satisfactorily applied over the upper surface 6b and the side surface 6c of the element 6a and the upper surface 8a of the support 8 without being discontinuous at the edge of the element 6a. The entire surface is covered with a blocking layer 7.

  Even when the transparent oxide film is made relatively thick (for example, about 2000 mm) in order to reduce the resistance (line resistance) in the longitudinal direction of the element 6a made of the transparent oxide film, the organic polymer is placed in the longitudinal direction of the element 6a. By applying, as shown in FIG. 7B, even when the edge step is large and steep, for example, a continuous thin film of about 50 to 500 nm (0.05 to 0.5 μm) is formed. It can be formed satisfactorily, and good blocking characteristics and interfacial crystallization suppression characteristics can be obtained. Further, by repeating the coating, the thickness can be further increased to about 5 μm.

  Further, similarly to the second embodiment, the blocking layer 7 can be provided with a function as a buffer layer, so that heat due to a difference in thermal expansion between the reading photoconductive layer 4 and the support 8 can be obtained. The stress can be relieved, and the problem of destruction due to the difference in thermal expansion does not occur even in a special environment as in the first and second embodiments.

On the other hand, when a thin film ITO having a thickness of about 2000 mm is formed and then a film of about 500 mm of CeO ₂ is laminated by resistance heating vacuum deposition, as shown in FIG. Since the edge step of the support 8 is large and steep, the blocking film made of CeO ₂ cannot cover the entire edge, and the film in the state shown in FIG. 7B cannot be formed. For this reason, the blocking performance is deteriorated and the S / N is lowered without being able to prevent the dark current injection from the portion indicated by 60 in FIG. Arise. This problem is that the thicker the element 6a (reading light side electrode layer 5), the larger the edge step, so that it becomes difficult to form a blocking film that continuously covers the entire surface, and the blocking performance is significantly deteriorated. become.

  Next, a basic method for recording image information as an electrostatic latent image on the electrostatic recording body 10 of the third embodiment and further reading the recorded electrostatic latent image will be briefly described. FIG. 8 is a schematic diagram showing a recording / reading system using the electrostatic recording body 10 of the third embodiment. In the figure, the support 8 is omitted.

  In this recording / reading system, the detection amplifier 81 is individually connected for each element 6a, and the element 6a is formed by line light as reading light extending in a direction (main scanning direction) perpendicular to the longitudinal direction of the element 6a. Is different from the system for the first embodiment in that an image signal is acquired by scanning in the longitudinal direction (sub-scanning direction).

  The reading light scanning unit 93 scans the reading light L2 that is substantially uniform in a line shape in the longitudinal direction of the element 6a (arrow direction in the figure) while being substantially orthogonal to the element 6a of the reading light side electrode layer 5. is there. If the electrostatic recording body 10 having the stripe electrode 6 is used, it is not necessary to scan with spot light such as a laser beam, so that the configuration of the scanning optical system can be made extremely simple and low-cost. Since a coherent light source can be used, interference fringe noise can be prevented.

  The current detection circuit 80 is provided with a detection amplifier 81 connected to each element 6a of the reading light side electrode layer 5, and the recording light side electrode layer 1 of the electrostatic recording body 10 is one of the connection means S3. The input and the negative electrode of the power supply 70 are connected, and the positive electrode of the power supply 70 is connected to the other input of the connection means S3. The output of the connecting means S3 is commonly connected to the non-inverting input terminal (+) of the operational amplifier 81a that constitutes each detection amplifier 81. Each element 6a is individually connected to the inverting input terminal (−) of the operational amplifier 81a. The detection amplifier 81 has a charge amplifier configuration including an operational amplifier 81a, an integration capacitor 81c, and a switch 81d.

  A process of recording an electrostatic latent image on the electrostatic recording body 10 according to the third embodiment will be described with reference to a cross-sectional view of the electrostatic recording body 10 shown in FIG. In the figure, the support 8 is omitted.

  Basically, it is the same as that of the first embodiment, but the way of storing charges in the power storage unit 23 is slightly different. First, a DC voltage is applied between each element 6a of the recording light side electrode layer 1 and the reading light side electrode layer 5 to charge both electrode layers. As a result, a U-shaped electric field is formed between the recording light side electrode layer 1 and the element 6a of the reading light side electrode layer 5, and most of the recording photoconductive layer 2 has a substantially parallel electric field. However, a portion where no electric field exists is generated at the interface between the photoconductive layer 2 and the charge transport layer 3 (see Z in FIG. 9A). The smaller the total thickness of the charge transport layer 3 and the reading photoconductive layer 4 is compared to the thickness of the recording photoconductive layer 2, and the smaller the ratio between the width and the pitch of the element 6a (75% or less). If the thickness of the charge transport layer 3 and the reading photoconductive layer 4 is substantially equal to or less than the pitch of the elements 6a, the portion where such an electric field does not exist is formed more clearly. .

  When the radiation L1 is blown onto the subject 9 in such a state, the negative charge among the positive and negative charge pairs generated by the radiation L1 transmitted through the transmission portion 9a is concentrated on the element 6a along the electric field distribution. (See FIG. 9B), an electrostatic latent image is recorded around the element 6a (see FIG. 9C). In particular, when the amount of radiation L1 is small, the negative charge is attracted to the center of the element 6a so that the accumulated charge is separated for each element 6a, and the accumulated charge is accumulated together with each element 6a. Therefore, the electrostatic latent image can be recorded with high sharpness (spatial resolution) by narrowing the pitch (pixel pitch) of the elements 6a. Furthermore, the concentration of the electric field on each element 6a can increase the reading efficiency and increase the S / N. In today's advanced semiconductor formation technology, it is easy to form the elements 6a with sufficiently narrow intervals, and therefore the electrostatic recording body 10 of the third embodiment is easily manufactured. be able to. It is to be noted that the positive charge of the positive and negative charge pairs generated in the recording photoconductive layer 2 is attracted to the recording light side electrode layer 1 and disappears in the same manner as in the first embodiment.

  When reading the electrostatic latent image recorded in this manner, the connecting means S3 is connected to the recording light side electrode layer 1 side of the electrostatic recording body 10, and the electrostatic recording body is connected via the imaginary short of the operational amplifier 81a. The electric charges are rearranged by setting the ten electrode layers 1 and 5 to the same potential. Next, the reading light conducting means 4 scans in the longitudinal direction of the element 6a with the line-shaped reading light L2 by the reading light scanning means 93, so that the reading photoconductive layer 4 on which the reading light L2 is incident is conductive as in the first embodiment. And an electric current flows in the electrostatic recording body 10. With this current, the integration capacitor 81c of the detection amplifier 81 connected to each element 6a is charged, charge is accumulated in the integration capacitor 81c according to the amount of flowing current, and the voltage across the integration capacitor 81c increases. Therefore, for each detection amplifier 81, the switch 81d is turned on between the pixels being scanned with the reading light L2 to discharge the charge accumulated in the integration capacitor 81c, so that both ends of the integration capacitor 81c are successively connected. A change in voltage is observed corresponding to the accumulated charge for each pixel. Since the change in voltage corresponds to the charge for each pixel accumulated in the electrostatic recording body 10, the electrostatic latent image can be read out by detecting the change in voltage.

  As described above, if the electrostatic latent image is read from the electrostatic recording body 10 by scanning in the longitudinal direction of the element 6a with the line-shaped reading light L2, the individual detection amplifier 81 can detect the electrostatic latent image in the main scanning direction. Thus, image signals can be obtained in parallel, and the reading time can be shortened. Further, since the reading light side electrode layer 5 is formed in a stripe shape, the distributed capacity due to the charge transport layer 3 and the reading photoconductive layer 4 is reduced, the detection amplifier 81 is less susceptible to noise, and the pixel pixel. Can be fixed at least at the element interval (pixel pitch), the image data can be corrected in accordance with the arrangement of the elements 6a, and the structure noise can be corrected accurately.

  Further, the latent image polarity charge attracts the element 6a of the reading light side electrode layer 5, and the transport polarity charge generated by the irradiation of the reading light L2 according to the electric field makes it easy to erase the latent image polarity charge. In this case, the sharpness can be kept high, and the effect is particularly high on the low light amount side during recording (that is, when the amount of accumulated charge is small). Sharpness can be further improved if the space between the elements 6a is light-shielding with respect to the reading light L2.

  Furthermore, since the electric field strength of the reading photoconductive layer 4 increases in the vicinity of the element 6a, a charge pair is generated by the reading light L2 in this strong electric field, so that the efficiency of exciton ion dissociation increases, and the charge pair As a result, the quantum efficiency of the generation can be made close to 1, so that the reading efficiency can be improved, the S / N can be increased, and the light energy density can be reduced. Furthermore, the capacity of the charge transport layer 3 and the reading photoconductive layer 4 can be reduced, and the signal extraction efficiency during reading can be increased.

  As described above, in the laminated structure of the image recording medium described in No. 4535468, it is difficult to form the stripe electrode in the final step of film formation, so it is difficult to obtain the effect as in the present invention, The significance of the electrostatic recording body to which the present invention is applied, in which the reading light side electrode layer is formed from the support side, is significant.

  In addition, when the light shielding portion and the transmission portion are provided at predetermined intervals in the longitudinal direction (scanning direction) of the element between the elements 6a and having a light shielding property with respect to the reading light L2, it corresponds to a so-called eyelet's eye. The reading light transmitting portion is formed as a reading light transmitting portion, and it is possible to avoid a reduction in spatial resolution due to light leakage with the reading light transmitting portion adjacent to the longitudinal direction of the element 6a during reading. Scan exposure is performed in parallel with a small spot beam, and a read image with extremely high sharpness can be obtained without converging the reading light L2 so much.

  Next, a fourth embodiment of the electrostatic recording body will be described. FIG. 10 is a perspective view (A) showing an outline of the electrostatic recording body according to the fourth embodiment and a partial cross-sectional view (B) thereof.

  The electrostatic recording body 10 of the fourth embodiment includes a recording light side electrode layer 1, a recording photoconductive layer 2, a charge transport layer 3, a reading photoconductive layer 24, a blocking layer 7, and a reading light side electrode layer. 5 and the support 8 are arranged in this order. Further, at the interface between the reading photoconductive layer 24 and the blocking layer 7, a substance that suppresses interface crystallization and a charge trap with a polarity opposite to that of the charge charged on the reading light side electrode layer are increased, and the same polarity. Doped with a material that reduces charge trapping.

  The blocking layer 7 in the present embodiment suppresses a-Se interface crystallization and charges the reading light side electrode layer 5 with a charge as in the blocking layer 7 of the first image recording medium. Blocking performance for 24 injections. Having this blocking performance prevents the charge from moving from the reading light side electrode layer 5 to the space charge layer formed at the interface with the blocking layer 5 of the reading photoconductive layer 24 described later. The conductive layer 24 has the ability to form a stable space charge layer at the interface with the blocking layer 7.

  Further, the reading photoconductive layer 24 in the present embodiment includes a substance that suppresses interface crystallization at the interface with the blocking layer as described above, and a charge having a polarity opposite to that of the charge on the reading light side electrode layer 5. The material is doped with a substance that increases the number of traps and decreases the number of traps of charge of the same polarity. As the substance for suppressing the interface crystallization, As is used as in the first embodiment, but the doping amount is preferably about 3 to 40 atom% unlike the first embodiment. Further, a positive charge is charged to the reading light side electrode layer 5 for a substance that increases trapping of charges having the opposite polarity to the charge charged on the reading light side electrode layer 5 and decreases trapping charges of the same polarity. In this case, Cl is preferably used, and Na is preferably used when the reading light side electrode layer 5 is charged with a negative charge. The doping amount is preferably about 1 to 1000 ppm. Cl emits holes and traps electrons when the reading light side electrode layer 24 is charged with a positive charge, and Na emits electrons and discharges holes when the reading light side electrode layer 5 is charged with a negative charge. Trap. As a result, a negative space charge layer or a positive space charge layer is formed at the interface between the reading photoconductive layer 24 and the blocking layer 7 in each case.

  Therefore, in the present embodiment, a negative space charge layer or a positive space which is stable at the interface between the reading photoconductive layer 24 and the blocking layer 7 by the above-described functions of the reading photoconductive layer 24 and the blocking layer 7. A charge layer is formed.

  The materials and manufacturing methods of the other layers are the same as those in the first and second embodiments.

  Next, a basic method of recording image information as an electrostatic latent image on the electrostatic recording body 10 having the above-described configuration and reading the recorded electrostatic latent image will be briefly described with reference to FIG. Note that the recording / reading system using the electrostatic recording body in the present embodiment is substantially the same as that in the first embodiment, and therefore the description thereof is omitted unless particularly necessary. In FIG. 11, the support 8 is omitted.

  When an electrostatic latent image is recorded on the electrostatic recording body 10, a DC voltage is applied between the recording light side electrode layer 1 and the reading light side electrode layer 5 by a power source 70, thereby recording light side electrode layer. 1 is charged with a negative charge, and the reading light side electrode layer 5 is charged with a positive charge (FIG. 11A). As a result, a parallel electric field (electric field) is formed between the recording light side electrode layer 1 and the reading light side electrode layer 5 in the electrostatic recording body 10.

  Immediately thereafter, at the interface of the reading photoconductive layer 24 with the blocking layer 7, the doped Cl emits holes to form a negative space charge layer (FIG. 11B). Since the blocking layer 7 prevents the charge from moving from the reading light side electrode layer 5 to the negative space charge layer, the negative space charge layer becomes a stable charge layer.

  Next, the radiation L1 is uniformly blown toward the subject 9. The radiation L1 passes through the transmission part 9a of the subject 9, and further passes through the recording light side electrode layer 1. The recording photoconductive layer 2 receives the transmitted radiation L1 (the radiation from the subject 9 becomes recording light), and generates a charge pair of electrons and holes according to the dose (light quantity) of the radiation L1, and becomes conductive. (FIG. 11C).

  The positive charges generated in the recording photoconductive layer 2 move at high speed in the photoconductive layer 2 toward the recording light side electrode layer 1, and the interface between the recording light side electrode layer 1 and the recording photoconductive layer 2. Thus, the negative charge charged on the recording light side electrode layer 1 is recombined and disappears. On the other hand, the negative charges generated in the photoconductive layer 2 move in the photoconductive layer 2 toward the charge transport layer 3. Since the charge transport layer 3 acts as an insulator for the latent image polar charge (negative charge in this example) having the same polarity as the charge charged on the recording light side electrode layer 1, it moves in the photoconductive layer 2. The negative charge thus generated stops at the power storage unit 23 formed at the interface between the photoconductive layer 2 and the charge transport layer 3 and is accumulated at this interface (power storage unit 23). On the other hand, since the radiation L1 does not pass through the light shielding part 9b of the subject 9, no change occurs in the portion corresponding to the lower part of the light shielding part 9b of the electrostatic recording body 10 (FIG. 11C).

  The reading photoconductive layer 4 and the charge transport are provided between the power storage unit 23 (interface between the recording photoconductive layer 2 and the charge transport layer 3) where the latent image polar charge is stored and the reading light side electrode layer 5. An electric field is formed according to the total thickness of the layer 3 and the amount of latent image polar charge. An electric field is also formed between the negative space charge layer and the reading light side electrode layer 5, and the electric field strength is locally increased in the negative space charge layer. FIG. 12 shows the relationship between the depth (distance) from the incident surface of the reading light and the strength of the electric field formed. In the negative space charge layer, as indicated by the solid line in FIG. 12, since the negative charges are uniformly distributed at a predetermined density, the electric field depends on the depth (approaching the incident surface of the reading light). Strength increases. In the case where the negative space charge layer is not formed, it is formed by the latent image polarity charge accumulated in the power storage unit and the positive charge charged in the reading light side electrode layer as shown by the broken line in FIG. Various average electric fields are distributed.

  Next, the recording light side electrode layer 1 of the electrostatic recording body 10 is set to the ground potential, and the reading light side electrode layer 5 is connected to the detection amplifier 91 of the current detection circuit 90. Then, the reading light side electrode layer 5 side of the electrostatic recording body 10 is scanned with the reading light L2. The reading light L2 is transmitted through the reading light side electrode layer 5, and in the reading photoconductive layer 24 irradiated with the reading light L2, positive and negative charge pairs are generated in accordance with the scanning to exhibit conductivity.

  Here, since the charge transport layer 3 acts as a conductor for the transport polar charge (positive charge in this example), the positive charge generated in the reading photoconductive layer 24 is a latent image of the power storage unit 23. It rapidly moves in the charge transport layer 3 so as to be attracted by the polar charge, and is recombined with the latent image polar charge in the power storage unit 23 and disappears. At this time, in the negative space charge layer formed at the interface between the reading photoconductive layer 24 and the blocking layer 7, the electric field strength is locally increased as described above. The generation efficiency of pairs can be improved. Accordingly, the intensity of the reading light is increased even when the number of electrons stored in the storage unit 23 is small and the electric field is weak (the recording light irradiated on the recording photoconductive layer is on the low dose side). And sufficient charge pair generation efficiency can be obtained. In order to efficiently obtain the above action, it is desirable that the thickness of the negative space charge layer region, that is, the region doped with As and Cl, be equal to or less than the absorption depth of the reading light.

  As described above, the latent image polarity charge accumulated in the electrostatic recording body 10 disappears, and a current change corresponding to this is detected by the current detection circuit 80 connected to the electrostatic recording body 10. Note that the negative space charge layer is also formed in the reading photoconductive layer corresponding to the non-irradiated portion of the recording light, and charge pairs can be generated by the irradiation of the reading light. 5, no electric field is formed between them, so that no current is detected.

  Although the preferred embodiment of the image recording medium of the present invention has been described above, the present invention is not necessarily limited to the above-described embodiment.

  For example, in the above description, the recording light side electrode layer is charged with a negative charge, the reading light side electrode layer is charged with a positive charge, and negatively charged in a power storage unit formed at the interface between the recording photoconductive layer and the charge transport layer. Although what has accumulated charge has been described, the present invention is not necessarily limited to this, and each may have a charge of opposite polarity. When the polarity is reversed in this way, hole transport is performed. The charge transport layer functioning as a layer may be changed to a charge transport layer functioning as an electron transport layer, and in the fourth embodiment, the reading photoconductive layer may be doped with Na instead of Cl.

  For example, a photoconductive material such as the above-mentioned amorphous selenium a-Se, lead (II) oxide, lead (II) iodide can be used in the same manner as the recording photoconductive layer, and N-trinitrofluorenyl can be used as the charge transport layer. Suitable examples include redene aniline (TNFA) dielectrics, trinitrofluorenone (TNF) / polyester dispersions, and asymmetric diphenoquinone derivatives.

  In any of the modifications of the first to third embodiments, interfacial crystallization is suppressed between the read photoconductive layer mainly composed of a-Se and the read light side electrode layer. When the blocking layer functioning as the suppression layer is not provided, the entire reading photoconductive layer or the interface between the reading photoconductive layer and the reading light side electrode layer is doped with a substance that suppresses interface crystallization. Needless to say, a blocking layer may be provided on the reading electrode layer, and the interface between the blocking layer and the reading photoconductive layer or the reading photoconductive layer may be doped with a substance that suppresses interface crystallization. .

  In the above embodiment, the power storage unit is formed at the interface between the recording photoconductive layer and the charge transport layer. However, the present invention is not limited to this, for example, as described in No. 4535468, the latent image polar charge The power storage unit may be formed of a trap layer that accumulates as a trap.

  In addition, the technique of suppressing interface crystallization by performing As doping on the interface between the a-Se of the reading photoconductive layer and the electrode of the reading light side electrode layer, or providing a blocking layer between both layers, It can also be applied to suppress interface crystallization at the interface between the recording photoconductive layer and the electrode of the recording light side electrode layer. For example, when the radiation that has passed through the subject is converted into visible light once by the phosphor layer and the electrostatic recording body is irradiated with the visible light, the recording light side electrode layer is transparent to visible light. Since a transparent oxide film such as ITO is inevitably used as an electrode material, it is meaningful to apply the present invention.

10 Electrostatic recording body 1 Recording light side electrode layer (second electrode layer)
2 Photoconductive layer for recording 3 Charge transport layers 4 and 24 Photoconductive layer for reading 5 Reading light side electrode layer (first electrode layer)
6 Stripe electrode 6a Element (Linear electrode)
7 Blocking layer (inhibition layer that suppresses interface crystallization)
8 Support
23 power storage unit 70 power supply 80, 90 current detection circuit 81, 91 detection amplifier

Claims (9)

To a support that is transparent to electromagnetic waves for reading,
A first electrode layer that is transparent to the electromagnetic wave for reading; a photoconductive layer for reading that exhibits conductivity by being irradiated with the electromagnetic wave for reading, the main component being a-Se; A storage unit for accumulating latent image polar charges generated in the photoconductive layer for recording, the recording photoconductive layer exhibiting conductivity by being irradiated with a recording electromagnetic wave, and a transparency to the recording electromagnetic wave. In the image recording medium formed by laminating the second electrode layer having this order,
Between the first electrode layer and the reading photoconductive layer, the injection of the electric charge charged in the reading electrode and having the transparency to the reading electromagnetic wave into the reading photoconductive layer. A suppression layer that has blocking performance and suppresses interface crystallization of the a-Se is provided,
A substance that suppresses interfacial crystallization of the a-Se and a charge opposite to the charge on the first electrode layer on the entire reading photoconductive layer or on the interface of the reading photoconductive layer with the suppression layer An image recording medium, which is doped with a substance that increases charge trapping and decreases charge trapping of the same polarity.   The image recording medium according to claim 1, wherein the substance that suppresses the interface crystallization is As.   The image recording medium according to claim 2, wherein the As is doped by 3 to 40 atom%.   When the charge charged on the first electrode layer is a positive charge, the substance that increases traps of charges having the opposite polarity to those charged on the first electrode layer and decreases traps of charges of the same polarity is Cl. The image recording medium according to claim 1, wherein the image recording medium is provided.   5. The image recording medium according to claim 4, wherein the Cl is doped with 1 to 1000 ppm.   When the charge charged on the first electrode layer is a negative charge, Na is a substance that increases traps of charges opposite in polarity to those charged on the first electrode layer and decreases traps of charges of the same polarity. The image recording medium according to claim 1, wherein the image recording medium is provided.   The image recording medium according to claim 6, wherein the Na is doped with 1 to 1000 ppm.   8. The image recording medium according to claim 1, wherein the doped region has a thickness of 0.01 to 0.1 [mu] m.   The image recording medium according to any one of claims 1 to 8, wherein a wavelength of the electromagnetic wave for reading is 350 to 550 nm.

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