JPH0672960B2 - Radiation sensitization screen - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to radiographic intensifying screens,
More specifically, the present invention relates to a radiation intensifying screen having excellent antistatic performance.

[Technical Background of the Invention] Radiographic intensifying screens are used in various fields such as medical radiography such as X-ray photography for medical diagnosis and industrial radiography for nondestructive inspection of substances. In order to improve the sensitivity of the photographing system, the radiographic film (for example, an X-ray photographic film) is used by being superposed so as to be in close contact with one side or both sides.

This radiation intensifying screen has, as a basic structure, a support and a phosphor layer provided on one surface thereof. The surface of the phosphor layer opposite to the support (the surface not facing the support) is generally provided with a transparent protective film made of a plastic film or the like. Protects against chemical alteration or physical shock.

The phosphor layer is composed of a binder that contains and supports phosphor particles in a dispersed state, and the phosphor particles have a property of exhibiting high-luminance emission when excited by radiation such as X-rays. is there. Therefore, the phosphor emits light with high brightness according to the amount of radiation passing through the subject, and the radiographic film placed in contact with the phosphor layer surface of the intensifying screen is superposed by the emitted light. Since it is also exposed to light, it is possible to achieve sufficient exposure of the radiation film with a relatively small radiation dose. Then, a radiation image of the subject is formed on the radiation film.

Radiographic photography is usually performed by placing the radiographic intensifying screen in a light-shielding cassette first, and then attaching a radiographic film to the cassette after each radiography to bring the intensifying screen and the radiographic film into close contact with each other, and in a light-shielded state. . However, since both the intensifying screen and the radiation film are made of a plastic material, when the radiation film is attached to or detached from the cassette, static electricity is generated due to contact between the two, the screen and the film are charged, and a discharge occurs between them, There is a problem that noise (static mark) is generated on the image obtained by exposing the film, and the diagnostic ability is deteriorated.

In addition, recently, a system for continuously photographing (without cassette) an intensifying screen and a radiation film on a cassette has been developed and used for the purpose of high-speed photographing. For example, in a device for angiography, a pair of intensifying screens are fixed in advance at the X-ray photographing position, and the many radiation films stored in the magazine in the device are automatically continuous one by one. It is transported and installed between both screens. After filming, the used film is again stored in the receiving magazine by the transport system, and at the same time, the unused film is placed between the screens. In this way, high-speed shooting is continuously performed.

In this cassette system, the radiation film is more likely to be charged than when a cassette is used.
This is because, in addition to the contact with the intensifying screen, static electricity occurs due to the contact between the films when they are sent out from the magazine to the transport system, or due to the rubbing between the film and the transport member during transport, and the film is charged. . Then, a discharge is generated between the film and the screen.

In order to prevent the occurrence of the charging and discharging phenomena, various techniques have been proposed and put into practical use for intensifying screens. For example, as a technique that is usually performed often, there is a method of coating or spraying a liquid antistatic agent on the surface of the screen, but since a coating film is simply formed on the screen surface, contact with a radiation film may cause a gradual increase. In particular, the coating film peels off and the antistatic function tends to decrease with the passage of time. In particular, in the case of the above-mentioned high-speed photographing system, since the number of times of photographing is large, the antistatic treatment (application of the antistatic agent) has to be repeated at appropriate intervals, which is troublesome in operation.

Further, as a technique for imparting antistatic performance to the radiation intensifying screen itself, for example, in JP-A-52-28284, a carbon black layer is provided between a support layer and a phosphor layer, and a protective film is charged. Techniques for incorporating an inhibitor have been disclosed. The carbon black layer and the protective film prevent the intensifying screen from being charged.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a radiation intensifying screen having improved antistatic performance.

Another object of the present invention is to provide a radiographic intensifying screen which suppresses the generation of static marks and gives a good image.

The above-mentioned purpose is a support, a phosphor layer comprising a binder containing and supporting the phosphor provided on the support in a dispersed state,
Then, in the radiographic intensifying screen having a protective film provided on the phosphor layer, a conductive polymer layer is attached between the protective film and the phosphor layer or between the phosphor layer and the support. Further, the present invention can be achieved by a radiation intensifying screen characterized in that a conductive edge sticking is provided in contact with the edge of the conductive polymer layer, and grounding is performed through the edge sticking.

The conductive polymer that constitutes the conductive polymer layer according to the present invention means that the molecular structure of the polymer itself has conductive properties.

The present invention provides a conductive polymer at any position (including a plurality of positions) between a support and a protective film of a radiation intensifying screen in which a phosphor layer and a protective film are laminated on the support. By providing the layer, the screen surface (the surface opposite to the support) can be prevented from being charged.

According to the present invention, by providing a layer made of a conductive polymer between the protective film of the radiographic intensifying screen and the phosphor layer or between the phosphor layer and the support, the screen surface is electrically stable. It can be maintained in a charged state (state of low charge). It is supposed that even if a large amount of electrified charges are generated on the screen surface, charges having the opposite sign to the surface charges are induced in the conductive polymer layer, so that apparently the screen surface has a very small amount of charge. Because it is done. Particularly, by providing the conductive polymer layer near the surface of the intensifying screen (between the phosphor layer and the protective film), an excellent antistatic effect can be obtained.

As a result, the radiation film used in close contact with the intensifying screen is less affected by the charging charge, and noise such as static marks is prevented from being generated on the image, and a good image can be obtained.

[Structure of the Invention] The radiographic intensifying screen of the present invention has a basic structure including a support, a phosphor layer, and a protective film, and is further provided with a conductive polymer layer. At least one conductive polymer layer is provided between the phosphor layer and the protective film of the intensifying screen or between the support and the phosphor layer.

At the edge of the radiographic intensifying screen of the present invention, a conductive edge sticking is provided in contact with the edge of the conductive polymer layer, and grounding is performed through the edge sticking.
A preferred layer structure of the intensifying screen of the present invention is shown in FIG.

1 (1) and 1 (2) are cross-sectional views for wetting an embodiment in which a conductive polymer layer is provided on a radiation intensifying screen having a three-layer structure including a support, a phosphor layer, and a protective film.

In FIG. 1, 1 is a support, 2 is a phosphor layer, 3 is a protective film, and 4 is a conductive polymer layer. In (1), the conductive polymer layer 4 is formed between the fluorescent light layer and the protective film. Then, in (2), it is provided between the support and the phosphor layer.

Further, two or more conductive polymer layers may be provided, and as an example, a second conductive polymer layer is further provided between the support of the intensifying screen shown in FIG. 1 (1) and the phosphor layer. May be attached. By providing two or more layers,
The antistatic effect can be further enhanced.

The layer structure of the radiation intensifying screen of the present invention will be described below by taking the intensifying screen having the layer structure shown in FIG. 1 (1) as an example.

The layer structure of the radiographic intensifying screen of the present invention is, for example,
It can be formed by the following method.

The support used in the present invention can be arbitrarily selected from various materials conventionally known as support materials for radiographic intensifying screens. Examples of such materials include films of plastic materials such as cellulose acetate, polyester, polyethylene terephthalate, polyamide, polyimide, triacetate, polycarbonate; metal sheets such as aluminum foil, aluminum alloy foil; ordinary paper, baryta paper, resin. Examples thereof include coated paper, pigment paper containing a pigment such as titanium dioxide, and paper such as paper sized with polyvinyl alcohol. However, in consideration of various properties as the radiation intensifying screen, a plastic film is a particularly preferable material for the support in the present invention. This plastic film may be kneaded with a light absorbing substance such as carbon black, or may be kneaded with a light reflecting substance such as titanium dioxide. The former is a support suitable for a high-sharpness type radiographic intensifying screen, and the latter is a support suitable for a high-sensitivity type radiographic intensifying screen.

In known radiographic intensifying screens, in order to strengthen the bond between the support and the phosphor layer, or to improve the sensitivity or image quality of the intensifying screen, gelatin such as gelatin is provided on the support surface on the side where the phosphor layer is provided. A polymer substance is applied to form an adhesion imparting layer (undercoat layer), or a light reflecting layer made of a light reflecting substance such as titanium dioxide or a light absorbing layer made of a light absorbing substance such as carbon black is provided. Is being done. Also in the present invention, these various layers can be provided.

Further, as described in JP-A-58-182599, in order to improve the sharpness, the surface of the support on the side where the phosphor layer is provided (adhesion is imparted to the surface on that side of the support). When a layer, a light reflection layer, or a light absorption layer is provided, the surface thereof may be provided with minute irregularities.

A phosphor layer is formed on this support.

The phosphor layer is a layer composed of a binder that contains and supports phosphor particles in a dispersed state.

Various types of phosphors are already known. Examples of phosphors that emit light in the near-ultraviolet to visible region preferably used in the present invention include the following compounds: Tungstate-based phosphors (CaWO ₄ , MgWO ₄ , CaWO ₄₎ : Pb
Etc.), terbium activated rare earth oxysulfide phosphor [Y ₂ O ₂ S:
Tb, Gd ₂ O ₃ S: Tb, La ₂ O ₂ S: Tb, (Y, Gd) ₂ O ₂ S: Tb, (Y, G
d) ₂ O ₂ S: Tb, Tm, etc.], terbium-activated rare earth phosphate-based phosphors (YPO ₄ : Tb, GdPO ₄ : Tb, LaPO ₄ : Tb, etc.), terbium-activated rare earth oxyhalide-based phosphors (LaOBr : Tb, La
OBr: Tb, Tm, LaOCl: Tb, LaOCl: Tb, Tm, GdOBr: Tb, GdOCl;
Tb, etc.), thulium-activated rare earth oxyhalide-based phosphors (LaOBr: Tm, LaOCl: Tm, etc.), barium sulfate-based phosphors [BaSO ₄ : Pb, BaSO ₄ : Eu ²⁺ , (Ba, Sr) SO ₄ : Eu ^2+, etc.], divalent europium-activated alkaline earth metal phosphate-based phosphor [Ba ₃ (PO ₄ ) ₂ : Eu ²⁺ , (Ba, Sr) ₃ (PO ₄ ) ₂ : Eu ^2+, etc.],
Divalent europium-activated alkaline earth metal fluoride halide phosphor [BaFCl: Eu ²⁺ , BaFBr: Eu ²⁺ , BaFCl: Eu ²⁺ , T
b, BaFBr: Eu ²⁺ , Tb, BaF ₂・ BaCl ₂・ KCl: Eu ²⁺ , BaF ₂・ BaC
_{l 2 · xBaSO 4 · KCl:} Eu 2+, (Ba, Mg) F 2 · BaCl 2 · KCl: Eu 2+
Etc.], iodide based phosphors (CsI: Na, CsI: Tl, NaI, KI: Tl
Etc.), sulfide-based phosphor [ZnS: Ag, (Zn, Cd) S: Ag, (Zn,
Cd) S: Cu, (Zn, Cd) S: Cu, Al, etc.], hafnium phosphate-based phosphors (HfP ₂ O ₇ : Cu, etc.), europium-activated rare earth oxysulfide-based phosphors [Y ₂ O ₂ S: Eu, Gd ₂ O ₂ S: Eu, La ₂ O ₂ S: Eu, (Y,
Gd) ₂ O ₂ S: Eu, etc.], europium-activated rare earth oxide-based phosphor [Y ₂ O ₃ : Eu, Gd ₂ O ₃ : Eu, La ₂ O ₃ : Eu, (Y, Gd) ₂ O ₃ : E
u], europium-activated rare earth phosphate-based phosphor (YPO ₄ : E
u, GdPO ₄ : Eu, LaPO ₄ : Eu, etc.), europium-activated rare earth vanadate phosphor [YVO ₄ : Eu, GdVO ₄ : Eu, LaVO ₄ : E
u, (Y, Gd) VO ₄ : Eu].

However, the phosphor used in the present invention is not limited to these phosphors, and may be any phosphor that emits light in the near-ultraviolet region or visible region upon irradiation with radiation such as X-rays. Good.

Examples of the binder for the phosphor layer include proteins such as gelatin,
Polysaccharides such as dextran or natural polymer substances such as gum arabic; and polyvinyl butyral, polyvinyl acetate, nitrocellulose, ethyl cellulose, vinylidene chloride / vinyl chloride copolymer, polyalkyl (meth) acrylate, vinyl chloride / vinyl acetate Examples thereof include binders represented by synthetic polymeric substances such as copolymers, polyurethane, cellulose acetate butyrate, polyvinyl alcohol, and linear polyester. Particularly preferred among such binders are nitrocellulose, linear polyesters,
Polyalkyl (meth) acrylates, mixtures of nitrocellulose and linear polyesters, and mixtures of nitrocellulose and polyalkyl (meth) acrylates.

The phosphor layer can be formed on the support by the following method, for example.

First, the above-mentioned phosphor and binder are added to an appropriate solvent and mixed sufficiently to prepare a coating liquid in which phosphor particles are uniformly dispersed in the binder solution.

Examples of the solvent for preparing the coating liquid include lower alcohols such as methanol, ethanol, n-propanol and n-butanol; chlorine atom-containing hydrocarbons such as methylene chloride and ethylene chloride; aromatic hydrocarbons such as benzene and toluene; Ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; esters of lower fatty acid and lower alcohols such as methyl acetate, ethyl acetate, and butyl acetate; ethers such as dioxane, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether; and Mention may be made of mixtures thereof.

The mixing ratio of the binder and the phosphor in the coating liquid varies depending on the characteristics of the intended radiographic intensifying screen, the kind of the phosphor, etc., but generally the mixing ratio of the binder and the phosphor is 1:
Selected from the range of 1 to 1: 100 (weight ratio), and in particular 1:
It is preferable to select from the range of 8 to 1:40 (weight ratio).

Although it is possible to form the phosphor layer by using a conductive polymer as the binder, since the polymer has a relatively weak adhesive force, when the polymer is used alone, the phosphor particles are not enough. When the polymer and other binders are used together to supplement the adhesive strength, the antistatic effect, which is the object of the present invention, can be sufficiently obtained. Absent. Therefore, when the phosphor layer is formed by using the phosphor and the binder in the above mixing ratio, it is not suitable for practical use as the binder of the conductive polymer phosphor layer.

In the coating liquid, a dispersant for improving the dispersibility of the phosphor particles in the coating liquid, and for improving the binding force between the binder and the phosphor particles in the phosphor layer after formation. Various additives such as plasticizers may be combined. Examples of the dispersant used for such a purpose include phthalic acid, stearic acid, cabroic acid, and lipophilic surfactants. Examples of plasticizers include phosphoric acid esters such as triphenyl phosphate, tricresyl phosphate, diphenyl phosphate; phthalic acid esters such as diethyl phthalate and dimethoxyethyl phthalate; ethyl phthalyl glycolate, butyl phthalyl butyl glycolate, etc. And a polyester of polyethylene glycol and a lipophilic dibasic acid such as a polyester of triethylene glycol and adipic acid, a polyester of diethylene glycol and succinic acid, and the like.

The coating liquid containing the phosphor and the binder prepared as described above is uniformly coated on the surface of the support to form a coating film of the coating liquid. This coating operation can be performed by using an ordinary coating means such as a doctor blade, a roll coater or a knife coater.

Then, the formed coating film is gradually heated to dry it to complete the formation of the phosphor layer on the support. The layer thickness of the phosphor layer varies depending on the characteristics of the intended radiation intensifying screen, the type of phosphor, the mixing ratio of the binder and the phosphor, etc., but is usually 20 μm to 1 mm. However,
The layer thickness is preferably 50 to 500 μm.

The phosphor layer does not necessarily have to be formed by directly applying the coating liquid on the support as described above.For example, the coating liquid may be separately applied on a sheet such as a glass plate, a metal plate, or a plastic sheet. After the phosphor layer is formed by drying, the phosphor layer may be bonded to the support by pressing it on the support or by using an adhesive.

Next, a conductive polymer layer is provided on the surface of the phosphor layer opposite to the side in contact with the support.

In the present invention, the conductive polymer layer is one in which the polymer itself constituting the conductive polymer layer has conductivity. The conductive polymer used in the present invention has a molecular structure such that electrons and holes can easily move. By dispersing a surfactant or the like, which is generally known as a conductive material, It is different from a composite material made conductive.

As the conductive polymer used in the present invention, for example,
Conductive acrylic resin (trade name; Colcoat NR-121, Colcoat Co., Ltd.) and siloxane bond (-Si-O-)
Examples of the polymer include Si-) (trade name; Colcoat R, manufactured by Colcoat Co., Ltd.). Here, the polymer containing a siloxane bond is a polymer having a three-dimensional network structure in which a monomer is solidified in the process of forming a coating film.

However, in the present invention, a conductive polymer having an arbitrary structure can be used as long as the polymer itself exhibits conductivity.

The conductive polymer layer is prepared by using a suitable solvent to prepare a coating solution containing the conductive polymer, and then uniformly coating the coating solution on the surface of the phosphor layer using the same ordinary coating means as described above. It can be formed by drying.

The layer thickness of the conductive polymer layer varies depending on the position where the layer is arranged, the characteristics of the polymer itself, etc., but generally the layer thickness is in the range of 0.1 to 20 μm, preferably 0.5 to 5.0.
It is in the range of μm. As a result, the surface resistance value of the conductive polymer layer can be set to 10 ⁹ Ω or less.

However, the conductive polymer layer may further contain a known conductive substance such as a surfactant.

Next, a transparent protective film is provided on the conductive polymer layer to physically and chemically protect the screen.

The transparent protective film may be, for example, a cellulose derivative such as cellulose acetate or nitrocellulose; or a transparent polymer material such as polymethylmethacrylate, polyvinyl butyral, polyvinyl formal, polycarbonate, polyvinyl acetate, vinyl chloride / vinyl acetate copolymer. It can be formed by a method of applying a prepared solution in which a suitable polymer substance is dissolved in a suitable solvent to the surface of the intermediate layer. Alternatively, it can also be formed by a method of adhering a transparent thin film formed in advance from polyethylene terephthalate, polyethylene, vinylidene chloride, polyamide or the like to the surface of the conductive polymer layer with an appropriate adhesive. The thickness of the transparent protective film is preferably about 1 to 30 μm.

In this way, the layer structure of the radiographic intensifying screen according to the present invention shown in FIG. 1 (1) can be obtained.

The radiation intensifying screen shown in FIG. 1 (2) is a support prepared separately, for example, after a conductive polymer layer is formed on a phosphor layer formed in advance and then the conductive polymer layer is on the inside. It can be obtained by attaching it above. In this case, the conductive polymer may be appropriately mixed with an adhesive or a polymer for the undercoat layer to form the polymer layer, or the conductive polymer may be formed into a light reflecting substance, a light absorbing substance, or the like. May be mixed to form a polymer layer. As a result, the conductive polymer layer can be provided with an antistatic function as well as a function as an adhesive layer, an undercoat layer, or a light reflecting layer or a light absorbing layer.

Further, an edge sticking made of a conductive material is provided at the edge of the radiographic intensifying screen of the present invention, and is grounded via this edge sticking. In the present invention, the conductive edge sticking serves as a ground wire connecting the conductive polymer layer and the grounding conductor (earth) (a kind of grounding member), and is provided at least at a part of the edge portion. Just do it.

FIG. 2 is a perspective view showing a mode in which a conductive edge sticking is provided on the edge of the radiographic intensifying screen (the mode shown in FIG. 1 (1)). In addition, FIG. 2-A is an I-I line of FIG.
It is sectional drawing which followed the line.

As shown in FIG. 2 and FIG. 2-A, on the side surface side of the edge portion 21 of the screen, a spot shape made of a conductive substance (for example, paste containing fine powder of metal such as tin, aluminum, silver) is formed. Edge bonding 22a is provided at several places. In addition, on the back surface side (support surface side) of the screen edge portion 21,
A tape-shaped edge sticker 22b made of a conductive material (for example, tin, aluminum, silver or a paste containing these metal powders) is attached to the spot-shaped edge sticker 22a. In the present invention, the spot-shaped conductive edge sticking 22a and the tape-shaped conductive edge sticking 22b are collectively referred to as the conductive edge sticking 22. Through this conductive edge sticking, charges having the opposite sign to the charges generated on the screen surface can be attracted to the conductive polymer layer from outside the screen.

On the other hand, when the intensifying screen is attached to the cassette or the device for high-speed photography as shown by the dotted line in FIG. 23 is preferably provided.

The conductive edge sticking is provided by coating or joining with an adhesive or the like.

In the present invention, the conductive edge sticking needs to be provided so as to be in contact with the conductive polymer layer. The conductive edging may be provided to cover the entire edge of the intensifying screen. Further, the tape-shaped conductive edge sticking may be provided not on the intensifying screen but on the cassette or the corresponding portion of the high-speed photographing apparatus together with the grounding portion.

Next, examples and comparative examples of the present invention will be described. However,
Each of these examples does not limit the invention.

Example 1 Terbium activated gadolinium oxysulfide phosphor (Gd ₂ O ₂ S: T
Methyl ethyl ketone was added to a mixture of the particles of b) and 80 parts by weight of a linear polyester resin (trade name: Byron # 500, manufactured by Toyobo Co., Ltd.), and 15 parts by weight of nitrocellulose having a nitrification degree of 11.5% and an isocyanate (commercial product) Name: Sumidur N-75, 5 parts by weight of Sumitomo Bayer Urethane Co., Ltd. was added, and the mixture was stirred and mixed with a propeller mixer to disperse the phosphor particles uniformly, and the binder and the phosphor were mixed. Mixing ratio with 1:16 (weight ratio) and viscosity is 25-30PS (25
(° C) was prepared.

Carbon black kneaded polyethylene terephthalate film placed horizontally on a glass plate (support, thickness: 250μ
The coating liquid was uniformly applied onto m) using a doctor blade. Then, after coating, the support with the coating film formed is placed in a dryer, and the temperature inside the dryer is set from 25 ° C to 100 ° C.
The coating film was dried by gradually raising the temperature to ℃. In this way, a phosphor layer having a layer thickness of 150 μm was formed on the support.

Next, conductive acrylic resin (trade name: Colcoat NR-
Methyl ethyl ketone was added to 50 parts by weight of 121, Colcoat Co., Ltd. to prepare a coating liquid containing a conductive acrylic resin.

This coating solution was applied on the phosphor layer by the same operation as above, and then dried to form a conductive polymer layer having a layer thickness of 2 μm.

Then, a transparent protective film was formed by placing a polyethylene terephthalate film (thickness: 12 μm, having a polyester adhesive) on the conductive polymer layer with the adhesive layer facing downward and adhering the film. .

In this way, a radiation intensifying screen composed of a support, a phosphor layer, a conductive polymer layer and a protective film was manufactured in this order [Fig. 1 (1)].

[Comparative Example 1] Commercially available radiographic intensifying screen (no conductive polymer layer, trade name: G-8, Fuji Medical Co., Ltd.)
Was used as a radiographic intensifying screen for comparison.

Next, with respect to each of the radiation intensifying screens of Example 1 and Comparative Example 1, the surface electricity quantity and the antistatic performance were evaluated using the test transporting device shown in FIG. The test transport device is a model of an angiographic imaging device described later.

FIG. 3 is a schematic sectional view showing a test transport device.

First, on a part of the protective film side surface of the radiation intensifying screen,
A tin foil was attached to measure the amount of charge on the screen surface.

In the test transporting device shown in FIG. 3, the intensifying screen 31a and the intensifying screen 31b provided with the tin foil 35 are fixed vertically with a certain space therebetween, and the radiographic film is placed between these screens. (Product name: NEW RXO-
G and Fuji Photo Film Co., Ltd. 32 are rollers 33a and 33b.
Is moved at a constant speed (180 m / min, the same speed as a commercially available angiography device). On the other hand, an electrometer (TR-8651 Takeda Riken Co., Ltd.) 34 is connected to the tin foil 35.

Electric charges are induced on the surface of the radiation film 32 according to the electric charges charged on the surface of the intensifying screen 31a. For example, if a negative charge is present on the surface of the screen 31a, a positive charge is induced on the surface of the film 32. Then, by electrically insulating the rollers 33a and 33b in advance, an electric charge having the same electric amount as this electric amount (plus electric charge) flows into the film 32 from the electrometer 34 through the tin foil 35 provided on the screen surface. . The electrometer 34 records a temporal change in the amount of electricity of the reflection code (corresponding to the amount of charge on the screen surface) equivalent to the flowed out charge. The maximum value QMAX (c) of the amount of electricity was used as the measured value.

Further, the presence or absence of noise (static mark) due to the electric charges induced in the radiation film was evaluated according to the following five grades. The noise of the film means a photosensitive portion on the film obtained by carrying out development processing after the film is carried by the test carrying device.

A: No static mark was generated.

B: Static marks were hardly generated.

C: Some static marks were generated.

D: Static marks occurred frequently.

The above results are summarized in Table 1.

As is clear from the results shown in Table 1, the layer structure of the radiation intensifying screen of the present invention having a conductive polymer layer (Example 1) was a commercially available radiation intensifying screen having no conductive polymer layer ( Compared to Comparative Example 1), the charge amount is about
It was reduced to 1/7 and the amount of static marks was small.

[Example 2] The same as the method of Example 1 except that a conductive polymer layer was formed on a support and then a phosphor layer and a transparent protective film were sequentially provided on the conductive polymer layer. By performing the operation, a radiation intensifying screen composed of a support, a conductive polymer layer, a phosphor layer and a protective film in that order was manufactured [Fig. 1 (2)].

Next, the radiation intensifying screens of Examples 1 and 2 and Comparative Example 1 were evaluated for surface electrification voltage and antistatic performance using a cassette shown in FIG.

FIG. 4 shows a perspective view of a cassette containing a pair of intensifying screens and a radiation film.

The cassette is composed of a housing portion 41 and a lid portion 42, and screens 43a and 43b are arranged in close contact with each other inside the lid portion 42 (upper side) and the housing portion 41 (lower side). Film 44
It is stored in a state of being sandwiched between both screens 43a and 43b.

First, a pair of intensifying screens were placed in the cassette as described above, and a commercially available radiation film having antistatic measures was rubbed and rubbed 30 times on the surface of each screen. Next, another commercially available radiation film (brand name: NEW RXO-G,
Fuji Photo Film Co., Ltd. was put between the screens, stored in a cassette for 5 minutes, and then taken out. The electrification voltage (V) of both screens at this time was measured. The presence or absence of static marks on the film obtained by developing the film was evaluated by the same criteria as above.

The screen electrification voltage (V) was measured by disposing a probe of an electrometer (electrostatic voltmeter, manufactured by Trek Corp.) at a height of 2.2 mm from the surface of the screen horizontally with respect to the surface.

The above results are summarized in Table 2.

As is clear from the results shown in Table 2, the layer constitution of the radiation intensifying screen of the present invention having a conductive polymer layer (Examples 1 and 2) is a commercially available radiation sensitizing layer having no conductive polymer layer. The electrification voltage was extremely low as compared with the screen (Comparative Example 1), and the amount of static marks generated was small.

[Example 3] The same operation as in Example 1 except that the edge of the intensifying screen was provided with a conductive edge paste composed of a silver paste and a silver tape, and was grounded with the silver tape. By carrying out, the support, the phosphor layer, and
A radiographic intensifying screen composed of a conductive polymer layer and a protective film and having a conductive border was manufactured [second
FIG. 2-A].

Comparative Example 2 In Comparative Example 1, an antistatic agent (trade name: Fuji AS Cleaner, manufactured by Fuji Photo Film Co., Ltd.) was applied on the protective film of the radiation intensifying screen.

Next, with respect to each of the radiation intensifying screens of Example 3 and Comparative Example 2, the surface electrification voltage and the antistatic performance were evaluated by the same method as described above using a cassette. The results are shown in Table 3.

As is clear from the results shown in Table 3, the radiation intensifying screen of the present invention (Example 3) having a conductive polymer layer and provided with a conductive edge coating was coated with an antistatic agent. Compared with the commercially available radiation intensifying screen (Comparative Example 2), the electrification voltage was extremely low and the amount of static marks generated was small.

Further, with respect to each of the radiographic intensifying screens of the above-mentioned Example 3, the surface electrification voltage and the antistatic performance were evaluated using the angiographic imaging device described below.

A pair of radiographic intensifying screens are attached to the angiography system (Siem
(ens-AOT, manufactured by Siemens), after fixing the shooting position,
A commercially available radiographic film (trade name: NEW RXO-G, manufactured by Fuji Photo Film Co., Ltd.) was continuously and automatically conveyed between both screens. The electrification voltage (V) of both screens (upper side and lower side) at this time and the presence or absence of static marks on the film were measured by the same method as described above.

The results are shown in Table 4.

As is clear from the results shown in Table 4, the radiation intensifying screen of the present invention (Example 3) having a conductive polymer layer and provided with a conductive edging has an extremely low electrification voltage, Tick marks were hardly generated (Example 3).

[Brief description of drawings]

FIG. 1 is a sectional view showing a preferable layer structure of the radiographic intensifying screen of the present invention. FIG. 2 is a perspective view showing a mode of the radiographic intensifying screen of the present invention, and FIG. 2-A is a sectional view taken along the line II of FIG. FIG. 3 is a schematic sectional view of the test transport device. FIG. 4 is a perspective view of the cassette. 1: Support, 2: Phosphor layer, 3: Protective film, 4: Conductive polymer layer, 21: Edge, 22: Conductive edge sticking, 22a: Spot-like conductive edge sticking, 22b: Tape-like Conductive edge sticking, 23: ground part, 31a, 31b, 43a, 43b: intensifying screen, 32, 44: radiation film, 33a, 33b: roller, 34: electron meter, 35: tin foil, 41: accommodation part, 42: Lid

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Jun Kawagoe 200, Onakazato, Fujinomiya-shi, Shizuoka Fuji Photo Film Co., Ltd. (56) References JP-A-52-28284 (JP, A) JP-A-61-264300 (JP, A) JP 54-133324 (JP, A) JP 54-20977 (JP, A) JP 56-32608 (JP, A) JP 61-174543 (JP, A) Kai 63-101800 (JP, A) JP 41-3296 (JP, B1)

Claims (3)

[Claims] 1. A radiation enhancer comprising a support, a phosphor layer comprising a binder provided on the support in a dispersed state and containing and supporting a phosphor, and a protective film provided on the phosphor layer. In the sensitive screen, a conductive polymer layer is attached between the protective film and the phosphor layer or between the phosphor layer and the support, and the conductive edge is in contact with the edge of the conductive polymer layer. A radiographic intensifying screen, which is provided with a paste and is grounded through the edge paste. 2. The radiation intensifying screen according to claim 1, wherein the conductive polymer layer is a layer made of a conductive acrylic resin or a polymer having a siloxane bond. 3. The conductive polymer layer has a layer thickness of 0.1 to 20 μm.
The radiographic intensifying screen according to claim 1, which is in the range of m.