JPH0545011B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an erasing unit for a stimulable phosphor sheet, and more specifically, when erasing a radiation image remaining on a stimulable phosphor sheet by irradiating erasing light, the present invention relates to an erasing unit for stimulable phosphor sheets. In an erasing unit configured to forcibly escape the generated hot air to the outside using an exhaust fan, the stimulable phosphor sheet conveyed inside the erasing unit is heated to a desired temperature while the exhaust fan is energized. The present invention relates to an erasing unit for a stimulable phosphor sheet configured to guide the stimulable phosphor sheet to a position and uniformly irradiate erasing light to erase image information remaining on the stimulable phosphor sheet.

2. Description of the Related Art Recently, a radiographic image information recording and reproducing system that obtains a radiographic image of a subject using a stimulable phosphor has been attracting attention. Here, storage 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 by irradiating it with excitation light such as visible light. The radiation image information recording and reproducing system described above utilizes this stimulable fluorophore, and the radiation image information of a subject such as a human body is stored on a sheet having a layer of stimulable phosphor (hereinafter referred to as ``stimulable fluorophore''). This stimulable phosphor sheet is scanned with excitation light such as a laser 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. Note that this type of technology is disclosed in Japanese Patent Laid-Open Nos. 55-12429 and 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. If this is used to output a visible image to a recording material such as a photographic material or a display device such as a CRT, a radiation image that is not affected by fluctuations in radiation exposure can be obtained.

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 record materials such as photographic light-sensitive materials, CRTs, etc. It is also possible to output a visible image to a display device, thereby obtaining a very great effect of obtaining a radiation image with excellent suitability for observation and interpretation (diagnosis suitability). In such a radiation image information recording and reproducing system, the stimulable phosphor sheet does not store the image information, but temporarily stores the radiation image information in order to ultimately provide the image to the recording medium as described above. Since this stimulable phosphor sheet is only for holding, it may be used repeatedly, and such repeated use is extremely economical and convenient.

Therefore, in order to reuse the stimulable phosphor sheet, the radiation energy remaining in the stimulable phosphor sheet after being read by irradiation with excitation light is released by irradiation with light. The image can be erased and the stimulable phosphor sheet can be used again for recording radiation images. A technique for removing radiation energy remaining in a stimulable phosphor sheet in this manner is disclosed in, for example, Japanese Patent Laid-Open No. 11392/1983.

By the way, inside the erasing mechanism, since it is necessary to emit almost all of the radiation energy remaining in the stimulable phosphor sheet, an erasing irradiation light source with as much luminosity as possible is arranged, and based on this irradiation light, the above-mentioned Erasing afterimages. However, in order for the light from this irradiation light source to almost completely erase the image remaining on the sheet in a short time, it is necessary to increase the number of light sources themselves and the amount of light, which results in excessive heat being applied to the erasing mechanism. This heat may damage the erasing mechanism main body, sheet, and peripheral mechanisms. For this purpose, it is conceivable to provide the erasing mechanism with a forced heat dissipation means such as an electric fan.

However, as will be described later, when this radiation image information recording/reproduction is of a standing type, for example, the erasing mechanism adopts a structure in which the stimulable phosphor sheet is conveyed vertically upward via a nip roller. Generally, when a stimulable phosphor sheet for erasing a residual image is introduced into the erasing mechanism under the biasing action of the forced heat dissipation means, the cooling caused by the forced heat dissipation means The disadvantage is that the wind can wind up the stimulable phosphor sheet, ie, cause it to bend, and the sheet is no longer conveyed to the desired position. In other words, in an upright radiation image information recording/reproducing system, an image recording section, an image reading section, and a residual image erasing section are generally arranged in a ring shape via a circulating conveyance system. In this case, for compactness, the transport system passing through the image reading section and residual image erasing section extends vertically, while the laser light from the laser light source is scanned to produce stimulated luminescence from the stimulable phosphor sheet. The conveyance system of the image reading section that obtains image information by obtaining light extends in the horizontal direction. Therefore, the stimulable phosphor sheet is introduced into the erasing mechanism through the image reading section,
At this time, if the forced heat dissipation means consisting of a fan or the like is energized, in order to suck the hot air inside the erasing mechanism and lead it out to the outside, the thin plate-shaped and highly flexible accumulative fluorescent light The body sheet is easily bent and cannot reach the optimal position for erasing the residual image. In order to avoid such inconveniences, it is naturally possible to arrange a plate-shaped guide member inside the erasing mechanism, but this guide member may cause shadows on the stimulable phosphor sheet. However, there is a problem in that residual images cannot be erased satisfactorily.

Therefore, as a result of intensive research and ingenuity, the inventor of the present invention made the erasing mechanism into a box shape, installed a duct that communicates with the outside in a part of this box, and equipped a part of the box that communicates with the duct with an electrically powered exhaust mechanism. In addition to disposing a fan, an opening for introducing and leading out the stimulable phosphor sheet is provided in the box, and a wire-shaped or thread-shaped guide member in the box is disposed in proximity to the opening. With this, the heat inside the box can be forcibly led out to the outside under the bias of the fan without reducing the irradiation efficiency of the erasing light to the stimulable phosphor sheet. The body sheet is effectively prevented from being bent, and since the guide member is wire-like or thread-like, it does not cast a clear shadow on the stimulable phosphor sheet, and therefore guides the erasure of residual images. It has been found that an erasing unit for a stimulable phosphor sheet is obtained which is substantially completely independent of the components and eliminates the aforementioned concerns.

Therefore, an object of the present invention is to guide the stimulable phosphor sheet to a desired position without bending it when erasing the residual radiation image on the stimulable phosphor sheet by irradiating it with erasing light; To provide an erasing unit for a stimulable phosphor sheet capable of forcibly releasing heat generated from an erasing light source to the outside and erasing a residual image without lowering the irradiation efficiency of erasing light.

In order to achieve the above object, the present invention irradiates a stimulable phosphor sheet on which a radiation image is stored and recorded with excitation light to emit the radiation image information as stimulated luminescence light. In an image reading mechanism that reads light using an optical element and converts it into an electrical signal, in an erasing mechanism that erases an image remaining on a stimulable phosphor sheet after reading by irradiating erasing light, the erasing mechanism has an internal a casing having an erasing light source disposed therein and having openings on both walls thereof for leading out and introducing a stimulable phosphor sheet; a conveying means for carrying the body sheet into the housing, positioning it at a predetermined position, and carrying it out from the predetermined position; an electric fan is disposed in the casing, and the other opening is disposed in the casing and is located close to at least one of the openings and facing the side of the stimulable phosphor sheet that is irradiated with the erasing light. It is characterized in that a linear guide portion extending a predetermined length on the side is provided.

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

First, a radiation image information recording/reading apparatus in which an erasing unit according to the present invention is incorporated together with an image recording section and an image reading section will be described with reference to FIGS. 1 and 2.

In FIG. 1, reference numeral 10 indicates a three-dimensional radiation image information recording/reading device, and the device 10 has a first housing 12 extending in the vertical direction and a second housing 14 extending in the horizontal direction. include. First housing 12
A photographing section (image recording section) 16 is disposed above the front surface of the camera, and an operation section 18 is disposed above the side wall thereof.

Next, the internal configurations of the first housing 12 and the second housing 14 will be described with reference to FIG. 2.

A pair of sheet receiving rollers 20 for receiving photographed sheets is disposed inside and below the image recording section 16, and below this pair of rollers 20 is a first guide member 22 and a pair of rollers corresponding to the guide member 22 and arranged vertically. A second guide member 24 extending in the direction is provided. The first and second guide members 22, 24
A third guide member 26 is further disposed below via a pair of rollers. A pair of rollers is pivotally supported between the third guide member 26 and a fourth guide member 28 provided below. Furthermore, a pair of rollers is provided below the fourth guide member 28,
An endless first conveyor belt 30 is bent at an inner corner of the first housing 12 below the pair of rollers.
will be provided. The conveyor belt 30 is connected to the second housing 1
Terminates at the bottom center of 4. Next, an endless second conveyor belt 32 is disposed at a slight distance from the terminal end of the first conveyor belt 30. The second conveyor belt 32 is bent upward at a corner of the second casing 14, and a roller group 34 is disposed at the inner bend. An endless third conveyor belt 36 and a fourth conveyor belt 38 extend horizontally at a distance from the terminal end of the conveyor belt 32. An endless fifth belt 40 is provided close to the terminal end of the fourth conveyor belt 38 and bent further upward. A roller group 42 is provided on one side of the belt 40. A pair of opposing guide members 44 is further disposed above the fifth conveyor belt 40 and the roller group 42, and a guide member 46 is disposed above the guide member 44 via a pair of rollers. be done. An erasing unit according to the present invention is incorporated above the guide member 46. Details of this erase unit will be described later.
A shorter guide member 48 is disposed above the erasing unit, and a guide member 50 is further disposed above the guide member 48. An endless bent conveyor belt 52 is provided at the end of the guide member 50 . As can be understood from the figure, this conveyor belt 52 is located approximately at the top of the first housing 12. This conveyor belt 52
Since the conveyor belt 52 is bent as described above, a roller group 54 is provided inside the conveyor belt 52 .
Furthermore, a pair of rollers 56 and 58 is provided below the conveyor belt 52 and the roller group 54,
The stimulable phosphor sheet is supplied to an image recording section 16 including a photographing surface 60.

The above is the basic configuration of the transport system for the stimulable phosphor sheet in the radiation image information recording/reading apparatus 10.

Next, a reading section arranged in relation to the transport system will be explained.

The reading unit 62 basically includes a laser light source 64, a scanning optical system (not shown) including a galvanometer mirror for scanning a sheet with laser light emitted from the laser light source 64, and a condensing reflection mirror 66.
and a condensing optical element 68 that effectively condenses a part of the stimulated luminescence emitted from the sheet by the scanning laser beam and the stimulated luminescence light reflected by the reflecting mirror 66. Note that a photomal 70 is attached to the condensing optical element 68 and the top.

Therefore, a unit according to the present invention is shown in FIG. 3 and subsequent figures. That is, reference numeral 100 in FIG.
indicates an erasing unit for stimulable phosphor sheets, and this erasing unit 100 basically consists of a housing 102, conveying means 104 and 106 disposed above and below both ends of the housing 102, and an erasing unit inside the housing 102. first to fourth light sources 10 for emitting light of
8a to 108d. In this case, it is effective for the housing 102 to reflect the erasing light from the light sources 108a to 108d if its inner wall is mirror-finished or a reflective thin film or plate is attached to the inner wall. . An angle member 110 is fixed to the lower end of the housing 102, and the angle member 110 is engaged with a part of the first housing 12, so that the housing 102 is positioned on the first housing 12. become. Openings 112a and 112b are formed in the housing 102 at positions corresponding to the transport means 104 and 106, respectively, and a guide member 113 is formed in the housing 102 near the openings 112a and 112b, respectively.
a to 113c and 114a to 114c are arranged side by side at equal intervals. In this case, the guide members 113a to 113c and the guide member 114a
114c to 114c are made by bending fine and highly rigid wire members into a right triangle shape, as shown in FIG.
The housing 10 is curved so as to go around one end of the housing 10.
It is fixed to the side wall of No. 2 with screws or the like. In this case, the guide members 113a to 113c and 114a to 114c may be made of a synthetic resin material with high heat resistance, and furthermore, the guide members 113a to 113c and 114a to 114c may be made of a synthetic resin body with high heat resistance, and furthermore, they have inclined surfaces directed toward the respective openings 112a and 112b with the erasing light source as the center. It is preferable that the sheet is formed so that the sheet can be guided smoothly as described below.

Next, outside the opening 112a, a pair of nip rollers 116a constituting the conveyance means 104,
116b are in sliding contact with each other.
7a, while the opening 1
12b as well, nip rollers 118a and 118b constituting the conveying means 106 are similarly disposed so as to be surrounded by the second housing 117b so as to be in sliding contact with each other. The nip rollers 116b and 118b are provided with an elastic member, that is, a coil spring 120a.
and 120b are suspended using the casings 117a and 117b, respectively, and the nip roller 116
b is forcibly brought into sliding contact with the nipping roller 116a, and the nipping roller 118b is forcibly brought into sliding contact with the nipping roller 118a. A casing 117 that surrounds the transport means 104 and the transport means 106 formed in this way
Holes 122a and 122b corresponding to the opening 112a are formed in the holes 122a and 117b.

Furthermore, a detection section 128 of a micro switch 126 is in sliding contact with the nip roller 116b. On the other hand, the angle member 11 that holds the housing 102
A motor 130 is fixed close to the rotary shaft 132 of the motor 130, and a first sprocket 1
34 is fixed. A chain 136 suspended on the first sprocket 134 is connected to the nip roller 11.
The second sprocket 1 is coaxially supported by the sprocket 6a.
38, and also engages with a third sprocket 140 that extends upward and is coaxially supported with the nip roller 118a. The chain 13
6 further engages with a fourth sprocket 142 for tension provided on the side wall of the housing 102, and returns to the first sprocket 134.

A shaft 144 holding the fourth sprocket 142 is configured to be displaced within a long hole 148 of a holding member 146 fixed to the housing 102 to hold the chain 136 at an optimum tension.

As a forced heat dissipation means for the casing 102, a through hole 154 is formed in the front wall surface 152 of the casing 102, which has a relatively small opening area and extends vertically. Through hole 15 has a larger opening area than through hole 154
A plurality of holes 8a to 158d (four in the figure) are formed, and the four through holes 158a to 158d are formed.
Electric fans 160a to 160d, which are driven in synchronization with the energization of the light sources 108a to 108d, respectively, are interposed therein. Furthermore, the side wall surface 15
6 are provided with the four through holes 158a to 158.
A duct member 162 having a rectangular cross section is connected so as to converge the ducts d at its base end. The tip opening 164 of the duct member 162 penetrates the inside of the first housing 12 described above and is opened to the outside of the radiation image information recording/reading apparatus 10 (see FIGS. 1 and 2).

On the other hand, inside the side wall surface 156, the side surface 1
Reflector body 16 that is one size smaller in area than 56
Bolt 16 configured by threading 6 at both ends.
8 or the like with a predetermined gap. That is, the reflector body 166 is as close to the light source 108 as possible.
The light sources 108a to 108d are arranged close to each other, and the surfaces on the light sources 108a to 108d are mirror-finished. In this case, a reflective thin film or a reflective thin plate may be attached to the surface of the reflective plate body 166 in place of the mirror finish. In addition, in the figure, reference numeral 170 indicates the mirror surface portion.

The erasing unit for stimulable phosphor according to the present invention is basically constructed as described above, and its operation and effects will be explained next.

When radiation is applied to a subject (not shown) on the imaging surface 60 of the image recording unit 16 and a radiation image of the subject is recorded on the stimulable phosphor sheet 150,
This stimulable phosphor sheet 150 includes a pair of rollers 20, guide members 24, 26, conveyor belts 30, 32, 3.
6 to the reading section 62. The reading section 62 scans the laser light sent from the laser light source 64 on the sheet 150, and thereby stimulates the stimulated luminescence light emitted from the sheet 150 either directly or by reflecting it on the mirror 66 to reach the optical element 68. Even the incident signal is converted into an electrical signal by the photomultiplier 70 and sent to a reproducing device (not shown).

After the reading operation is completed, the stimulable phosphor sheet 150 whose image signal has been read in this way is transferred to the guide member 4 via the conveyor belts 38 and 40.
4, and further reaches the nip rollers 116a and 116b via the guide member 46. That is, the sheet 150 introduced from the hole 122a is guided into the housing 102 by the nip rollers 116a and 116b, and in this way, the nip roller 11
When the sheet 150 is sandwiched between 6a and 116b,
Due to its thickness, the nip roller 116b lifts up against the tensile force of the coil spring 120a. Therefore, the detection section 128 of the microswitch 126 detects this. When the motor 130 is rotated by this detection signal, the chain 136 is moved, and this movement of the chain 136 causes the second sprocket 138 to rotate. As mentioned above, the second sprocket 138 is connected to the nip roller 1.
Since the nip roller 116a is disposed coaxially with the rotation axis of the sprocket 16a, the nip roller 116a, which rotates under the rotational action of the sprocket 138, simultaneously rotates the nip roller 116b that is in sliding contact with the nip roller 116a, and the sheet 150 introduced therebetween is vertically upwardly moved. Derived into. That is, when the sheet 150 is fed from the reading section side as described above, the micro switch 126 whose tip part contacts the nip roller 116b is activated.
The contacts are closed and the resulting electrical signal causes motor 130 to rotate.

By the way, in this way, the Nitsu Pro roller 116
The sheet 150 is introduced into the housing 102 from the opening 112a while being held between the light sources 108a, 108b, 108c and 108d inside the housing 102.
On the other hand, the hot air inside the housing 102 generated by these light sources 108a to 108d is led outside by driving the electric fans 160a to 106d. That is, inside the housing 102, there is always an airflow flowing in the direction of arrow B in FIG. 3 due to the electric fans 160a to 160d. Therefore, the highly flexible sheet 150
tends to bend in the flow direction of the air flow, as shown by the broken line. However, according to the present invention,
Since the guide members 114a to 114c are arranged inside the housing 102, the bending of the leading end of the sheet 150 is restricted by these guide members 114a to 114c, and the leading end of the sheet 150 is preferably moved toward the opening 112b. You will be guided. That is, sheet 150
The distal end portions of the guide members 114a to 114c come into contact with the inclined surfaces and are guided along the inclined surfaces toward the opening 112b. In this way, the sheet 150 passes through the opening 112b and the nip rollers 118a, 118 rotate under the action of the third sprocket 140.
At point b, the sheet 150 separates from the nip rollers 116b, 116a, so the nip roller 116b is displaced in the direction of arrow A in FIG. 3 due to the action of the coil spring 120a. As a result, the detection section 128 of the microswitch 126 is also displaced in the same direction. Therefore, the displacement signal is sent to motor 130, causing it to rotate in the opposite direction. That is, the Nitsu Pro roller 118
The sheet 150 held by the rollers a and 118b returns again toward the nip rollers 116a and 116b.
During this time, similarly to the above, the airflow flowing in the direction of arrow B due to the drive of the electric fans 160a to 160d tends to roll up the tail end of the sheet 150 and bend it in the direction of the fans. However, such action is preferably prevented by the guide members 113a to 113c. That is, the tail end of the sheet 150 comes into contact with the inclined surfaces of the guide members 113a to 113c and is guided toward the opening 112a. When the sheet 150 is held again by the nip rollers 116a and 116b, the detection section 128 of the microswitch 126 is displaced again due to its thickness, and this displacement signal causes the motor 130 to stop. In this way, the sheet 150 is transferred to the nip rollers 116a, 116b and the nip roller 118a,
118b.

During this time, the light sources 108a, 108b, 108c, and 108d remain lit. Therefore, the illumination light emitted from the light sources 108a to 108d is sufficiently reflected inside the housing 102 and focused onto the stimulable phosphor sheet. In this case, the light source 10
Guide members 113a to 113c and 114a to 114c are present between 8a to 108d and the sheet 150. However, since these guide members are substantially made of thin wire shapes, they do not cause any shadows, and
Since the inside of the casing 102 is mirror-finished, the reflected light is diffusely reflected, and clear shadows of the guide members 113a to 113c and 114a to 114d are not cast on the surface of the sheet 150. In this way, the remaining radiation image inside the housing 102 is almost completely erased. Note that the light source 108
When the lights a to 108d are turned on, the electric fans 160a to 160d are operating as described above, so the high temperature air inside the housing 102 due to the heat generated by the light sources 108a to 108d flows as shown by arrow B in FIG. 162 and is discharged to the outside via this duct member 162, at the same time colder air than the passage 154 is introduced. Therefore, the inside of the housing 102 is forcibly cooled by the cooling air introduced through the through holes 154.

After the erasing operation is performed in this manner, the motor 130 is energized again to move the chain 136, and the sheet 150 is moved between the nip rollers 118a and 11.
8b and is transferred toward the guide member 48. Since the residual image on the stimulable phosphor sheet 150 that has reached the guide member 48 has already been almost completely erased, the conveyor belt 52 and roller pair 56, 58
Even if the radiation image is sent to the image recording unit 16 via the image recording unit 16, there is no problem in taking the next radiographic image.

According to the present invention, in the standing type radiation image information recording and reproducing system as described above, a fan is provided inside the erasing mechanism incorporated therein for guiding the hot air generated by the erasing light source to the outside, and on the other hand, In order to avoid bending of the stimulable phosphor sheet under the influence of the airflow generated by the fan, a guide member is provided which is made of a thin wire-like member. This prevents flexing of the stimulable phosphor sheet within the housing, while preventing the guide member from projecting its own shadow onto the sheet under the bias of the erasing light source. The lid is closed, the guide member is made of a wire-like thin metal or synthetic resin member, and the inner wall surface of the erasing box constituting the erasing mechanism has a mirror finish with high reflection efficiency, or a reflective film corresponding thereto is formed. This is because the irradiated light is effectively reflected diffusely and the shadow of the guide member itself is appropriately reduced.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to this practical embodiment. In the case of a structure in which the seat is not positioned, the same effect can be obtained by simply providing a guide member only on the inner wall of the upper part of the housing, and various improvements and design changes can be made without departing from the gist of the present invention. Of course, this is possible.

[Brief explanation of the drawing]

FIG. 1 is an overall perspective view of a radiation image information recording/reading device, FIG. 2 is a longitudinal cross-sectional view of the device shown in FIG. 1, and FIG. 3 is an example of an embodiment of the erasing unit for stimulable phosphor sheets of the present invention. 4 is a side view of the unit shown in FIG. 3, FIG. 5 is a perspective view of the unit shown in FIG. 3, and FIG. 6 is an erasing unit showing the arrangement of the guide member of the present invention. It is a partially omitted perspective explanatory view. 10...radiation image information recording/reading device, 12,
14... Housing, 16... Photographing section, 18... Traveling section, 20... Sheet receiving roller pair, 22, 24,
26, 28... Guide member, 30, 32... Conveyor belt, 34... Roller group, 36, 38, 40...
... Conveyor belt, 42 ... Roller group, 44, 46,
48, 50...Guide member, 52...Transport belt, 54...Roller group, 56, 58...Roller pair, 60...Photographing surface, 62...Reading unit, 64...
Laser beam, 66... Reflection mirror for focusing, 68...
...Condensing optical element, 70...Photomar, 100...
... Erasing unit for stimulable phosphor sheet, 102...
...Housing, 104, 106...Transportation means, 108,
108d...Light source, 110...Angle member, 1
12a, 112b...opening, 113a to 113
c, 114a to 114c... guide member, 116
a, 116b...Nippon roller, 117a, 11
7b... Housing, 118a, 118b... Nip roller, 120a, 120b... Coil spring, 126... Micro switch, 128... Detection unit, 130... Motor, 132... Rotating shaft, 1
34...Sprocket, 136...Chain, 1
38, 140, 142... Sprocket, 144
... shaft, 146 ... holding member, 148 ... long hole,
150...Stormable phosphor sheet, 152...Front wall surface, 154...Through hole, 156...Side wall surface, 158
a~158d...Through hole, 160a~160d...
Electric fan, 162... Duct member, 164...
Tip opening, 166...reflector body, 168...bolt, 170...mirror surface portion.

Claims (1)

[Claims] 1. A stimulable phosphor sheet on which a radiation image has been accumulated is irradiated with excitation light to emit the radiation image information as stimulated luminescence light, and this stimulated luminescence light is read by an optical element. In contrast to an image reading mechanism that converts an image into an electrical signal, an erasing mechanism that erases an image remaining on a stimulable phosphor sheet after reading by irradiating erasing light, wherein the erasing mechanism is provided with an erasing light source inside. a housing having openings on both walls thereof for leading out and introducing the stimulable phosphor sheet, and a housing disposed inside or outside the housing to carry the stimulable phosphor sheet into the housing; and a conveyance means for positioning the eraser at a predetermined position and carrying it out from the predetermined position, and the housing includes an electric fan for discharging hot air generated inside the housing by lighting the erasing light source to the outside. a predetermined length of the stimulable phosphor sheet on the side of the other opening, which is close to at least one of the openings and opposite to the side of the stimulable phosphor sheet that is irradiated with the erasing light; 1. An erasing unit for a stimulable phosphor sheet, characterized in that it is provided with a linear guide member extending by . 2. In the unit according to claim 1, the guide member is disposed between the electric fan and one opening, and between the electric fan and the other opening, for a stimulable phosphor sheet. Elimination unit. 3. An erasing unit for a stimulable phosphor sheet according to claim 2, wherein the guide member has an inclined portion directed from the erasing light source to one opening and the other opening. 4. An erasing unit for a stimulable phosphor sheet according to claim 1, wherein at least a portion of the inner wall surface of the housing is mirror-finished. 5. An erasing unit for a stimulable phosphor sheet according to claim 1, wherein the housing has a reflective thin film or reflective thin plate attached to at least a part of its inner wall. 6. An erasing unit for a stimulable phosphor sheet, which comprises the unit as claimed in claim 1, wherein a reflecting plate is provided between the electric fan and the erasing light source. 7. An erasing unit for a stimulable phosphor sheet according to claim 6, wherein the reflecting plate has a mirror-finished surface on the light source side. 8. An erasing unit for a stimulable phosphor sheet according to claim 6, wherein the reflecting plate has a reflective thin film or a reflective thin plate attached to the light source side surface.