JPH0550729B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stimulable phosphor sheet erasing unit for erasing radiation image information remaining on the stimulable phosphor sheet by irradiating the sheet with erasing light from an erasing light source. More specifically, an air blower for cooling the stimulable phosphor sheet is provided in a casing surrounding the erasing light source, and the forced cooling air from the air blower is provided inside the casing. The present invention relates to an erasing unit for a stimulable phosphor sheet, which is provided with means for preventing the stimulable phosphor sheet from flying up and coming into contact with an erasing light source.

Recently, a radiation image information recording and reproducing system that obtains a radiation image of a subject using a stimulable phosphor has been attracting attention. Here, stimulable phosphors are radiation (X-rays, α-rays, β-rays, γ-rays, electron beams, ultraviolet rays, etc.)
A phosphor that accumulates a portion of this radiation energy when irradiated with it, and then emits stimulated luminescence light corresponding to the accumulated energy when it is later irradiated with excitation light such as visible light.

The radiation image information recording and reproducing system described above utilizes this stimulable phosphor, and once the radiation image information of a subject such as a human body is recorded on a sheet having a layer made of a stimulable phosphor (hereinafter referred to as a ``stimulable phosphor sheet'').
This stimulable phosphor sheet is scanned with excitation light such as a laser beam to generate stimulated luminescent light, and the resulting stimulated luminescent light is photoelectrically transmitted. An image signal is obtained by reading the image signal, and based on this image signal, a radiation image of the subject is output as a visible image to a recording material such as a photographic light-sensitive material, or a CRT or the like.

Regarding this type of technology, please refer to Japanese Patent Application Laid-open No. 55-
It is disclosed in No. 12429, No. 56-11395, etc.

Incidentally, this system has the practical advantage of being able to record images over a much wider radiation exposure range than conventional radiographic systems using intensifying screens and X-ray films.

That is, in a stimulable phosphor, it is recognized that the amount of emitted light that is stimulated to emit light due to excitation after accumulation is proportional to the amount of radiation exposure over an extremely wide range. Therefore, even if the amount of radiation exposure varies considerably due to various imaging conditions, the amount of emitted light is read by the photoelectric conversion means with the reading gain set to an appropriate value and converted into an electrical signal. By using this electrical signal and outputting it as a visible image to a recording material such as a photographic light-sensitive material or a display device such as a CRT, it is possible to obtain a radiation image that is not affected by fluctuations in the amount of radiation exposure.

In addition, according to this system, after converting the radiation image information stored in the stimulable phosphor into an electrical signal, appropriate signal processing is performed, and this electrical signal is used to display on recording materials such as photographic light-sensitive materials, CRTs, etc. It also has the extremely great effect of outputting it as a visible image to the device, thereby obtaining a radiographic image with excellent follow-up suitability for observation (diagnosis suitability).

In such a radiation image information recording and reproducing system, the stimulable phosphor sheet does not store the image information, but temporarily retains the radiation image information in order to finally provide the image to the recording medium as described above. This stimulable phosphor sheet may be used repeatedly, and it is extremely economical and convenient to use it repeatedly in this way.

Therefore, in order to reuse the stimulable phosphor sheet, the radiation energy remaining in the stimulable phosphor sheet after reading has been performed by irradiation with excitation light is released by irradiation with light, and the residual radiation image information is This stimulable phosphor sheet can be used again for recording radiation images. A technique for erasing radiation energy remaining in a stimulable phosphor sheet by irradiating it with light is disclosed, for example, in Japanese Patent Application Laid-Open No. 56-11392.

By the way, since it is necessary to almost completely emit the radiation energy remaining in the stimulable phosphor sheet inside the erasing mechanism, a high-intensity erasing light source is installed, and the above-mentioned Deleting residual image information. However,
In order for the light from this erasing light source to almost completely erase the image information remaining on the sheet in a short time, it is necessary to increase the number of light sources and the amount of light. The generated heat becomes excessive, and this heat may damage the eraser mechanism, the sheet, and peripheral equipment.

In particular, stimulable phosphor sheets, for example,
-146447, it consists of a support made of an organic polymer material such as polyethylene terephthalate, paper, etc., and a phosphor layer provided on this support. It consists of a binder made of an organic polymer material such as cellulose, and stimulable phosphor particles dispersed in this binder. Further, generally, a transparent protective film is provided on one side of the phosphor layer (the surface opposite to the support side of the phosphor layer) to physically or chemically protect the phosphor layer. This transparent protective film is also made of an organic polymer material such as polyethylene terephthalate. As described above, stimulable phosphor sheets are made of organic materials that are easily deformed and altered by heat, so if the heat from the erasing light source becomes excessive, the sheets will be deformed and altered, making reuse difficult. There is a problem that the product may deteriorate or become impossible to reuse in some cases.

By the way, since the erasing mechanism is for removing the radiation increase information remaining in the stimulable phosphor sheet after reading the radiation image information, it is preferable that it be integrated into the radiation image information reading device. In this case, the erasing mechanism itself needs to be constructed compactly so that it can be easily incorporated and the entire device can be made compact. The erasing mechanism is a box type that includes a casing in which an erasing light source is disposed, and a conveying means disposed inside or outside the casing to convey the stimulable phosphor sheet to a predetermined position. We have already proposed an erasing unit for stimulable phosphor sheets (Japanese Patent Application No. 112532/1983,
No. 112533 and Japanese Patent Application No. 112534 (Sho 59-112534). However,
In the box type erasing mechanism, the problem that the stimulable phosphor sheet is adversely affected by the heat from the erasing light source becomes even more serious.

Therefore, as a result of intensive studies and efforts, the inventors of the present invention found that when the erasing mechanism is made into a box shape for the sake of compactness, the upper surface of the stimulable phosphor sheet introduced into the box is It was discovered that if a fan is installed to forcefully blow air to cool the stimulable phosphor sheet, the stimulable phosphor sheet itself will not be damaged even if the heat dissipated from the erasing light source becomes excessive. Furthermore, if a means for preventing the air blown by the fan from blowing up the stimulable phosphor sheet is provided close to the light source, the stimulable phosphor sheet will come into contact with the erasing light source, causing the stimulable phosphor sheet to fluoresce. It has been found that an erasing unit can be obtained that does not cause damage to the body sheet or the erasing light source.

Therefore, an object of the present invention is to enable a compact structure and to prevent the stimulable phosphor sheet itself from being damaged by the heat applied to the stimulable phosphor sheet from the erasing light source. An erasing mechanism for a stimulable phosphor sheet that is possible and that does not damage the erasing light source or the stimulable phosphor sheet itself due to the stimulable phosphor sheet flying up and coming into contact with the erasing light source. It is on offer.

In order to achieve the above object, the present invention irradiates a stimulable phosphor sheet on which radiation image information is stored and recorded with excitation light to emit the radiation image information as stimulated luminescence light. In contrast to an image reading mechanism that reads light using an optical element and converts it into an electrical signal, in an erasing mechanism that erases image information remaining on a stimulable phosphor sheet after reading by irradiating erasing light, the erasing mechanism is , a casing, and a transport means disposed within or outside the casing for transporting the stimulable phosphor sheet to a predetermined position, an erasing light source that irradiates erasing light onto a stimulable phosphor sheet that is carried into the body; a cooling air blower provided with an outlet directed toward the surface of the stimulable phosphor sheet that is irradiated with the erasing light; A stimulable phosphor sheet is interposed between the stimulable phosphor sheet and the erasing light source, and is capable of irradiating the stimulable phosphor sheet with the erasing light and prevents the stimulable phosphor sheet from coming into contact with the erasing light source. The invention is characterized by being provided with means for doing so.

Further, the present invention is characterized in that the blocking means is a heat-resistant net provided apart from the irradiation surface of the stimulable phosphor sheet.

Next, preferred embodiments of the erasing unit for stimulable phosphor sheets according to the present invention will be described in detail with reference to the accompanying drawings.

First, with reference to FIG. 1, the following describes an apparatus in which the erasing unit of the present invention is incorporated together with an image recording section and an image reading section, and a plurality of stimulable phosphor sheets are used in circulation, that is, a radiation image information recording/reading apparatus. Explain.

The radiation image information recording/reading device 10 generally performs erasing to completely erase the image recording section 12, image reading section 14, and residual image information and wait for the recording of image information on the stimulable phosphor sheet again. Part 1
Contains 6. The image reading section 14 is provided with a light shielding member 17 that is optically isolated from the erasing section 16 and other parts to prevent the intrusion of light that causes noise, as shown by a dashed line.
is provided. The image recording section 12 includes a first belt conveyor 20 for positioning the stimulable phosphor sheet 18, and an anti-scattering button 22 disposed above the belt conveyor 20 for preventing scattering of radiation. An imaging device 26 including a radiation source is arranged further upwardly from the imaging surface 24 of the image recording section 12.

Next, a second belt conveyor 28 is arranged adjacent to the positioning belt conveyor 20, and a bent third belt conveyor 30 faces the second belt conveyor 28. Note that a roller group 32 composed of three rollers is arranged at the bent portion of the belt conveyor 30.

A guide plate 3 is provided below the third belt conveyor 30.
4 is arranged, and this guide plate 34 faces a bent fourth belt conveyor 36 further below. A second roller group 38 is disposed at the bent portion of the fourth belt conveyor 36.

On the other hand, a fifth belt conveyor 40 is disposed close to the fourth belt conveyor 36, and this fifth belt conveyor 40 faces a sixth belt conveyor 42 disposed inside the image reading section 14. The other end of the sixth belt conveyor 42 faces a bent seventh belt conveyor 44, and a third roller group 46 is disposed at the bent portion of the seventh belt conveyor 44. On the output side of the seventh belt conveyor 44 that bends with the roller group 46, an eighth belt conveyor 48 and a ninth belt conveyor 50, which are arranged in a straight line, are further arranged. A laser light source 52 is disposed above the belt conveyors 48 and 50, and an optical system, that is, a mirror 54, is provided to main scan the output laser light 53 in the width direction of the stimulable phosphor sheet 18 on the belt conveyor 48. ,
A galvanometer mirror 55, a mirror 56, and a mirror 57 are provided.

Next, one end of the ninth belt conveyor 50 passes through the light shielding member 17 and faces the erasing section 16 . The erasing section 16 basically consists of a casing 62, a plurality of erasing light sources 64a to 64d provided inside the casing 62, and fans 66a to 66d disposed above the casing 62. Means and this housing 6
Conveying means 68a, 68b adjacent to the opening of No. 2
including. A bending tenth belt conveyor 70 is arranged outside the conveying means 68a, and this tenth belt conveyor 70 is bent.
A fourth roller group 72 is provided at the bent portion of the belt conveyor 70, and an eleventh belt conveyor 74 which is connected to the tenth belt conveyor 70 and bends in the same way is provided at the bent portion. A fifth roller group 76 is provided. Further, a twelfth belt conveyor 78 is provided adjacent to the eleventh belt conveyor 74 and the fifth roller group 76. No.
The twelve belt conveyor 78 has a bent structure as described above, and therefore, the sixth roller group 80 is disposed at the bent portion. Furthermore, the twelfth belt conveyor 78 includes a bending thirteenth belt conveyor 8.
2 is disposed, and in this case as well, a seventh roller group 84 is disposed at the bent portion thereof, as described above.

The radiation image information recording/reading device 10 is basically configured as described above.
With reference to the drawings, a more detailed explanation will be given of the erasing section 16, particularly related to the present invention.

That is, the casing composing the erasing unit designated by the reference numeral 62 has transport means 68a and 68b disposed at both ends thereof, and a first to third casing for irradiating erasing light into the casing 62. It includes fourth light sources 64a to 64d. By the way, in this case,
The light sources 64a and 64d are arranged parallel to each other on one side 90a of the housing 62 with a considerable distance apart, and the light sources 64b and 64c are arranged close to and parallel to each other on the other side 90b of the housing 62. will be placed.
That is, the light sources 64b, 64c are the light sources 64a, 6
4d. and,
A large opening/closing lid 92 is attached to the side portion 90a with screws or the like. On the other hand, openings 94a, 94b, and 94c are provided below the side portion 90b, and each of the openings 94a to 94c is provided with a forced cooling air blower, that is, preferably, a cooling fan 96a, 96b, and 96c, respectively. Keep the outlet facing the outlet. A belt conveyor 98 is disposed at the bottom of the housing 62, and the belt conveyor 98 has rollers 100 constituting the conveying means 68a, 68b.
a, 100b. In fact, the conveying means 68
Rollers 100a and 100b that constitute a and 68b
are surrounded by cover members 101a and 101b, respectively. Therefore, the cover members 101a, 101b
An opening 102 is formed in each of the openings 102 for introducing the stimulable phosphor sheet 18 into the housing 62 and for leading out the erased stimulable phosphor sheet to the outside.

Furthermore, in this embodiment, the housing 62
has a structure in which its bottom is closed, and the conveying means 6
8a and 68b are arranged inside the housing 62. However, it goes without saying that the present invention is also applicable to an erasing mechanism configured, for example, in which the bottom of the casing is open and the conveying means is disposed below the open bottom.

Next, a motor 103 is fixed to one side of the casing 62, and a first sprocket 105 is fitted to the rotating shaft 104 of the motor 103. A chain 106 suspended on the first sprocket 105 meshes with a second sprocket 107 coaxially supported on the roller 100b, and furthermore, the chain 106 is suspended on the first sprocket 105.
A third sprocket 108 extends to the 0a side and is fitted coaxially to the rotating shaft of the roller 100a.
mesh with. The chain 106 further includes the housing 6
No. 4 for tension installed on the side wall of No. 2.
After engaging with the first sprocket 110, the second sprocket returns to the first sprocket 105. 4th sprocket 11
The shaft 112 holding the chain 106 is displaced within a long hole 116 of a holding member 114 fixed to the housing 62 to hold the chain 106 with optimum tension.

Note that in the above configuration, the housing 6
The inner surface of the side wall 2 has a mirror finish, and furthermore, the erasing light sources 64a to 64d and the fan 6
If a top plate 118 with a mirror-finished lower surface is suspended between 6a and 66d, the light sources 64a to 6
This is preferable because the erasing light from 4d is effectively reflected (see FIG. 3).

Next, in this embodiment, a baffle member 200 is disposed at an intermediate portion between the erasing light sources 64a to 64d and the Shirotsuko fans 96a to 96c. The baffle member 200 is substantially the same as the Shirotzko fan 96.
When forced cooling air is supplied by a to 96c, the relatively thin stimulable phosphor sheet 18
This exists to prevent the phosphor sheet 18 from flying up, thereby causing the phosphor sheet 18 itself to come into contact with any of the light sources 64a to 64d, melting and adhering, or damaging the light sources 64a to 64d.

Preferably, the baffle member 200 is configured in the form of a mesh with a wire member that is relatively thick and small, that is, has a thickness that does not prevent the irradiation light from the light sources 64a to 64d from reaching the stimulable phosphor sheet 18. ing. Note that the shape of the baffle member 200 does not necessarily have to be mesh-like, and the stimulable phosphor sheet 18, such as a wire member arranged in parallel, can be used as the light source 64a to 64.
Any material may be used as long as it can prevent contact with d. When the baffle member 200 is constituted by such a wire member, especially if the baffle member 200 is brought as close as possible to the light sources 64a to 64d, the shadow of the baffle member 200 will have no effect on the stimulable phosphor sheet 18. Therefore, it is preferable because it does not interfere with its erasure.

For this purpose, it goes without saying that, for example, the baffle member 200 can be made of a highly transparent glass plate or the like that does not interfere with the emission of light from the erasing light sources 64a to 64d. It is.

The erasing unit for stimulable phosphor sheets according to this embodiment is basically constructed as described above, and its functions and effects will be explained.

When a subject 122 such as a human body is lying on the top plate 120 that constitutes the radiation image information recording/reading device 10, radiation is emitted from the imaging device 26 onto the subject 12.
When the radiation is irradiated onto the subject 122, the radiation passes through the photographing surface 24 and is prevented from scattering by the button 22.
A radiographic image of a desired portion of the image is recorded. The recorded stimulable phosphor sheet 18 is then conveyed toward the image reading section 14. That is, it reaches the bent belt conveyor 30 via the belt conveyor 28, and from there it passes through the guide plate 34 and reaches the belt conveyor 36 again. The stimulable phosphor sheet 18 drawn out from this belt conveyor 36 is
It reaches a belt conveyor 40, passes through belt conveyors 42 and 44, and is positioned on a belt conveyor 48. Here, the output laser beam 53 from the laser light source 52 is main-scanned on the stimulable phosphor sheet 18 by the reciprocating motion of the galvanometer mirror 55, and in synchronization with this main scanning, the stimulable phosphor sheet 18 is transferred onto the belt conveyor. 48, the paper is conveyed in a direction substantially perpendicular to the main scanning direction to perform sub-scanning. As a result, the stimulable phosphor sheet 18 emits stimulated light based on the image information of the subject 122 stored and recorded therein, and this light is collected by the light condensing element 60, which is then exposed to a photo attached to the light condensing element 60. It is photoelectrically read through a multilayer and converted into an electrical signal, and based on this electrical signal, the radiation image of the subject is displayed directly on a CRT (not shown), or on a recording material such as a photosensitive material. It will be recorded. Therefore, since the stimulable phosphor sheet 18 that has undergone stimulated luminescence still has residual image information, this stimulable phosphor sheet 18 is conveyed to the erasing section 16 via the belt conveyor 50. That is, when the stimulable phosphor sheet 18 held in sliding contact by the conveyor 68b with the roller 100b is introduced into the casing 62, this image information is uniformly spread over the remaining stimulable phosphor sheet 18. Erasing light is emitted from light sources 64a to 64d. At this time, Sirotskovan 96a to 96c
supplies cooling air at a predetermined amount to the stimulable phosphor sheet 18, while the fans 66a to 66d disposed at the top of the housing 62 are energized.

In this case, when the Shirotsuko fans 96a to 96c are energized, the stimulable phosphor sheet 18 inside the housing 62 may be blown up by the forced cooling air and come into contact with any of the light sources 64a to 64d. be. However, by providing the baffle member 200 as described above, even if the phosphor sheet 18 flies up, the baffle member 200 prevents it from reaching the light sources 64a to 64d, and this adverse effect is completely prevented.

Therefore, the heat emitted from the light sources 64a to 64d and staying near the stimulable phosphor sheet 18 is cooled down by the cooling effect of the Sirotskov fans 96a to 96c, while the fans 66a to 66d force the heat to the outside. It acts to derive. As a result, the stimulable phosphor sheet 18 receives light for erasing its residual image, while the light source 6
The heat from 4a to 64d is not received, and therefore, the phosphor sheet 18 remains in the housing 62 while being kept at a relatively low temperature. After a predetermined period of time, the residual image on the stimulable phosphor sheet 18 is almost completely erased, and then the image is transferred from the conveying means 68a including the rollers 100a to the conveying belt conveyor 70.
will be sent to This belt conveyor 70 transports the stimulable phosphor sheet 18 onto belt conveyors 74, 7.
8 and 82, and waits for the next radiation image recording.

In addition, in the embodiment shown in FIG. 2, generally the Sirotskov fans 96a to 96c have the angle of the forced cooling air outlet, that is, the angle θ shown in FIG.
The angle of the wind outlet with respect to the horizontal direction shown in 5° ~
It is preferable to set the angle to 15°. That is, the stimulable phosphor sheet 1 introduced into the erasing housing 62
8 does not necessarily have the same size,
Although stimulable phosphor sheets 18 of various sizes can be introduced, since the wind discharge direction of the Sirotskov fans expands in a fan shape with respect to the vertical direction, the angles of the wind discharge openings of the Sirotskov fans 96a to 96c may be adjusted in this manner. With this configuration, no matter what size of the stimulable phosphor sheet 18 is introduced into the housing 62, the cooling air can be spread over the entire upper surface of the stimulable phosphor sheet 18. Efficient cooling is possible.

As explained above, according to the present invention, the erasing mechanism can be configured compactly, and
The heat emitted from the erasing light source when the erasing light is emitted can be prevented from being transmitted onto the stimulable phosphor sheet, and as a result, the stimulable phosphor sheet is prevented from being damaged by the heat from the erasing light source. The effect of preventing this from happening can be obtained. Therefore, it is possible to make the erasing mechanism more compact, and the durability of the stimulable phosphor sheet can be increased.
It is also possible to increase the durability of the erasing mechanism itself.

Furthermore, the present invention is provided with a means that can irradiate the stimulable phosphor sheet with erasing light and prevent the stimulable phosphor sheet from coming into contact with the erasing light source. This provides the effect of avoiding damage to the stimulable phosphor sheet or the erasing light source.

Although the present invention has been described above in detail by citing preferred embodiments, the present invention is not limited to this embodiment. It goes without saying that various improvements and changes in design are possible without departing from the gist of the present invention, such as the fact that these can be used in a radiation image information reading device configured separately from the image recording section. be.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional explanatory view of a radiation image information recording, reading and reproducing unit incorporating the erasing unit for stimulable phosphor sheets according to the present invention, and FIG. 2 is a partially cutaway schematic perspective view of the erasing unit shown in FIG. 1. FIG. 3 is a longitudinal sectional view showing the positional relationship of the stimulable phosphor sheet, the light source, and the baffle member in the erasing unit shown in FIG. 2. 10... Radiographic image information recording/reading device, 12...
...image recording section, 14...image reading section, 16...erasing section, 17...light shielding member, 18...stimulable phosphor sheet, 20...belt conveyor, 22...button key, 24...imaging surface, 26... Photography device, 2
8, 30... Belt conveyor, 32... Roller group, 34... Guide plate, 36... Belt conveyor, 38... Roller group, 40, 42, 44... Belt conveyor, 46... Roller group, 48, 50...
...Belt conveyor, 52...Laser light source, 53...
... Laser light, 54, 56, 57 ... Mirror, 55
... Galvanometer mirror, 60 ... Condensing element,
62... Housing, 64a to 64d... Erasing light source,
66a-66d... Juan, 68a, 68b...
Conveying means, 70, 74, 78, 82... Belt conveyor, 72, 76, 80, 84... Roller group,
90a, 90b...Side part, 92...Opening/closing lid, 94
a~94c...Opening, 96a~96c...Shirotsukofan, 98...Belt conveyor, 100
a, 100b...roller, 101a, 101b...
... Cover member, 102 ... Opening, 103 ... Motor, 104 ... Rotating shaft, 105, 107, 10
8,110...Sprocket, 106...Chain, 112...Shaft, 114...Holding member, 116
...Long hole, 118...Top plate, 122...Subject,
200... Obstruction member.

Claims (1)

[Claims] 1. A stimulable phosphor sheet on which radiation image information is accumulated and recorded is irradiated with excitation light to emit the radiation image information as stimulated luminescence light, and this stimulated luminescence light is emitted by an optical element. An erasing mechanism that erases image information remaining on a stimulable phosphor sheet after reading by irradiating erasing light with respect to an image reading mechanism that reads and converts it into an electrical signal, the erasing mechanism comprising: a housing; a conveyor disposed within or outside the housing for conveying the stimulable phosphor sheet to a predetermined position; an erasing light source that irradiates the stimulable phosphor sheet with erasing light; a cooling air blower provided with an outlet directed toward the surface of the stimulable phosphor sheet to which the erasing light is irradiated; and the stimulable phosphor sheet. means interposed between the erasing light source and capable of irradiating the stimulable phosphor sheet with the erasing light and preventing the stimulable phosphor sheet from coming into contact with the erasing light source; An erasing unit for a stimulable phosphor sheet, characterized in that: 2. The stimulable phosphor unit according to claim 1, wherein the blocking means is a heat-resistant mesh provided apart from the irradiation surface of the stimulable phosphor sheet. Erase unit for sheets.