JP2005352106A - Image reading apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a uniform, satisfactory image which makes it possible to make a diagnosis with high efficiency. <P>SOLUTION: An image reading apparatus is designed such that when a drive means is driven, a storage phosphor sheet is subjected to main scanning by a main scanning means while a hold means is moved in a direction opposite to the direction of the movement of a balance weight. At least a hold-means-side link between one end of a transmission means and a hold means or a weight-side link between the other end of the transmission means and the balance weight is connected to the transmission means so as to be turnable in the direction in which the transmission means meanders. The hold-means-side link or weight-side link is connected to the transmission means so as to be turnable around a connection support shaft via a bearing in the direction in which the transmission means meanders. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image reading apparatus that reads radiation image information accumulated in a stimulable phosphor sheet.

  Radiation images such as X-ray images are often used for disease diagnosis and the like. Traditionally, in order to obtain such a radiographic image, X-rays that have passed through a subject are irradiated onto a phosphor layer (phosphor screen), thereby generating visible light and taking a normal photograph of this visible light. Similarly, so-called radiographs in which a film using a silver salt was irradiated and developed were used. However, in recent years, a technique has been devised for extracting an image directly from a phosphor layer without using a film coated with silver salt. As an example of this method, radiation that has passed through a subject such as a patient is absorbed by the phosphor, and then the phosphor is accumulated by the above-described absorption by exciting the phosphor with, for example, light or thermal energy. Some of them emit radiation energy as fluorescence, and detect and image this fluorescence.

  Specifically, for example, a radiation image conversion method using a stimulable phosphor and using visible light or infrared light as stimulating excitation light is disclosed (for example, Patent Documents 1 and 2). This method uses a photostimulable phosphor sheet in which a photostimulable phosphor layer is formed on a support, and the stimulable phosphor layer of the photostimulable phosphor sheet is irradiated with radiation transmitted through a subject. The radiation energy corresponding to the radiation transmittance of each part of the subject is accumulated to form a latent image, and then the stimulable phosphor layer is scanned with the stimulating excitation light to radiate the accumulated radiation energy of each part. Then, this is converted into light, and the intensity of this light is converted into an image signal through a photoelectric conversion means such as a photomultiplier to obtain a radiation image as digital image data.

  Based on such digital image data, an image is formed on a silver salt film, or an image is output to a CRT or the like for visualization. The digital image data is stored in an image storage device such as a semiconductor storage device, a magnetic storage device, or an optical disk storage device, and then taken out from these image storage devices as necessary, via a silver salt film, CRT, LCD, etc. Can be visualized.

By the way, when the photostimulable phosphor sheet is scanned with photostimulable excitation light, the photostimulable phosphor sheet and the photostimulable excitation light source must be precisely moved relative to each other at a constant speed. For this reason, in the prior art, a method has been proposed in which a stimulable phosphor sheet and a counterweight are connected by a metal belt, and the metal belt is driven to scan an image (for example, Patent Documents 3 and 4).
U.S. Pat. No. 3,859,527 Japanese Patent Application Laid-Open No. 55-12144 (pages 1 to 6, FIGS. 1 to 3) JP 2002-277999 A (page 1 to page 19, FIGS. 1 to 6) JP 2002-278000 (page 1 to page 16, FIGS. 1 to 5)

  In such a system in which the stimulable phosphor sheet and the counterweight are connected by a metal belt and the image is scanned by driving the metal belt, vibration in the traveling direction of the stimulable phosphor plate is caused by a belt resonance attenuation mechanism or the like. Is decreasing. However, since the metal belt is long and is only supported by a drive pulley, a guide pulley, or the like, the metal belt may meander when the metal belt is driven.

  Due to such meandering of the metal belt, the feed rate unevenness of the photostimulable fluorescent plate is aggravated. As a result, there is a problem that image unevenness occurs and the efficiency of diagnosis is lowered.

  The present invention has been made in view of the problems of the prior art, and is capable of obtaining a good image without image unevenness, and thereby providing an image that can be diagnosed with good diagnostic efficiency. An object of the present invention is to provide a simple image reading apparatus.

  In order to solve the above-described problems and achieve the object, the present invention is configured as follows.

The invention according to claim 1 is a plate-like member attached with a stimulable phosphor sheet, or holding means for holding the stimulable phosphor sheet;
Guide means for guiding the holding means;
Driving means for driving the holding means to move;
Transmission means for moving the holding means;
Drive transmission means for transmitting the drive of the drive means to the transmission means;
A counterweight connected to the holding means via the transmission means;
Main scanning means for scanning in a direction orthogonal to the moving direction of the holding means,
When the driving means is driven, the storage means moves in the direction opposite to the moving direction of the counterweight, and the stimulable phosphor sheet is configured to be main scanned by the main scanning means,
At least one of a holding means side connecting portion between one end of the transmitting means and the holding means, or a weight side connecting portion between the other end of the transmitting means and the counterweight can be rotated in the meandering direction of the transmitting means. The image reading apparatus is connected to

 In addition, a plate-shaped member is a member to which a stimulable phosphor sheet can be attached, and is a plate-shaped member. Specific examples thereof include a back plate and a front plate of a cassette for a stimulable phosphor sheet, but are not limited thereto, and may be a member other than the cassette. The holding means is means for holding a plate-like member attached with the stimulable phosphor sheet or the stimulable phosphor sheet, for example, like the sub-scanning moving plate shown in the embodiment. The transmission means is formed of, for example, a “thin plate or linear material” used in the definition of “B65H” of the IPC classification such as a web like a belt or a wire shown in the embodiment. It is preferable. Further, the driving means is preferably one that rotates and drives like the motor shown in the embodiment, but is not limited thereto. In addition, the drive transmission means may be a gear that transmits gears like the speed reduction mechanism shown in the embodiment. It may be.

The invention according to claim 2 is characterized in that the holding means side connecting portion or the weight side connecting portion is
2. The image reading apparatus according to claim 1, wherein a connecting fulcrum shaft is connected to a fulcrum so as to be rotatable in a meandering direction of the transmission means via a bearing.

According to a third aspect of the present invention, the holding means side connecting portion or the weight side connecting portion is
A connecting fulcrum shaft supported by the holding means or the counterweight via fulcrum shafts at both ends, and having an attachment surface to which the end of the transmission means is attached;
A receiving means that is inserted into an attachment hole formed in an end portion of the transmission means, is attached to an attachment surface of the connection fulcrum shaft, and holds the end portion of the transmission means;
3. The image reading apparatus according to claim 1, further comprising: the bearing inserted between the mounting hole of the transmission unit and the receiving unit. 4.

  According to a fourth aspect of the invention, there is provided the image reading apparatus according to any one of the first to third aspects, wherein the transmission means is a metal belt.

  With the above configuration, the present invention has the following effects.

  According to the first aspect of the present invention, at least one of the holding means side connecting part between the one end of the transmitting means and the holding means or the weight side connecting part between the other end of the transmitting means and the counterweight is connected to the transmitting means. Since it is pivotally connected in the meandering direction, even when a force is applied to the transmission means in the meandering direction when the transmission means is driven, the meandering of the transmission means is absorbed by the holding means side connection part or the weight side connection part. It is not transmitted to the holding means or the counterweight. As a result, it is possible to prevent unevenness in the feeding speed of the photostimulable fluorescent plate due to meandering of the transmission means, and it is possible to obtain a good image without image unevenness, and thereby provide an image that can be diagnosed with good diagnostic efficiency. Is possible.

  According to the second aspect of the present invention, the meandering of the transmitting means is connected to the holding means side connecting portion or the weight by a simple structure in which the connecting fulcrum shaft is pivotally connected to the supporting point via the bearing in the meandering direction of the transmitting means. It is possible to prevent absorption by at least one of the side connecting portions and transmission to the holding means and the counterweight.

  According to the third aspect of the invention, the end of the transmission means is held by the receiving means on the mounting surface of the connecting fulcrum shaft, and the bearing is inserted between the mounting hole of the transmission means and the receiving means. The meandering of the means is absorbed via the bearing, and the meandering of the transmission means can be prevented from being transmitted more reliably to the holding means and the counterweight.

  According to the fourth aspect of the present invention, the transmission means is a metal belt, and the rigidity of the metal belt can prevent uneven feeding speed of the photostimulable fluorescent plate.

  Hereinafter, an embodiment of the image reading apparatus of the present invention will be described, but the present invention is not limited to this embodiment. The embodiment of the present invention shows the most preferable mode of the present invention, and the present invention is not limited to this.

  FIG. 1 is a perspective view showing a cassette used in the image reading apparatus. The cassette 1 is composed of a separable front plate 10 and a back plate 20, and FIG. 1 shows a state where the front plate 10 and the back plate 20 of the cassette 1 are separated. The front plate 10 includes a frame 11 and a front plate 13.

  The frame 11 is preferably made of a material that can withstand a large load during full weight photography, such as aluminum or hard plastic, and the front plate 13 is relatively small in radiation absorption, such as aluminum or carbon fiber reinforced plastic. It is preferable to form with a member.

  A cassette of the type that opens and closes the side of the cassette or pulls out the side plate of the cassette has a structure that is weak against the load from the front because the outer periphery of the cassette cannot be configured with a continuous structure. On the other hand, in this embodiment, the frame 11 of the front plate 10 has a structure that seamlessly covers the outer periphery of the front plate 13, so that the load applied from the front plate 10 side of the cassette 1 during photographing is evenly distributed throughout the frame 11. Can take it. For this reason, it has an extremely strong structure against the load applied from the front plate 10 side. On the front plate side surface 110, grip recesses 16a and 16b are formed.

  The back plate 20 is formed of a back plate body 21, a support plate 27 provided with a lead foil on the back surface, and a stimulable phosphor sheet 28, and the stimulable phosphor sheet 28 is fixed to the support plate 27. ing. The back plate main body 21 is preferably formed of a ferromagnetic plastic so that it can be attracted to the rubber magnet 54 of FIG. 3 by magnetic force. Alternatively, the back plate body 21 may be formed of ordinary plastic, and a ferromagnetic sheet such as iron foil may be attached to the back surface of the back plate 20. Further, a method of applying a ferromagnetic substance to the back surface of the back plate 20 may be used.

  Further, the back surface of the back plate 20 is designed such that the back surface of the back plate 20 follows a plane formed by the rubber magnet 54 when attracted to the rubber magnet 54. In other words, the back plate 20 has a certain degree of rigidity and is flexible enough to follow the plane formed by the rubber magnet 54. In this way, by providing the back plate 20 with a certain degree of flexibility, even if the back plate 20 is deformed or warped due to aging or usage, for example, the back plate 20 follows the plane on the rubber magnet 54 side. The deformation and warpage of the are corrected. Therefore, the surface of the photostimulable phosphor sheet 28 can always be kept flat when reading image information.

  When photographing with a load (such as bed photographing or full load photographing) is performed from the front plate 10 side, a situation occurs in which the front plate 13 of the front plate 10 has a considerable amount on the back plate 20 side. At this time, if the rigidity of the back plate 20 is too high, the back plate 20 maintains flatness, so that the stimulable phosphor sheet 28 is pressed by a considerable amount from both the front plate 10 and the back plate 20. And damage the stimulable phosphor. As described above, if the back plate 20 has both a certain degree of rigidity and a certain degree of flexibility, the back plate 20 can be somewhat changed in the direction of escaping from the pressing from the front plate 10. Therefore, the stimulable phosphor sheet 28 is not damaged. Of course, the back plate 20 should not have more flexibility than necessary. If the back plate 20 is given more flexibility than necessary, the durability of the cassette 1 is lowered. Further, if the back plate 20 is given more flexibility than necessary, the back plate 20 will loosen due to its own weight, causing a problem with light-shielding properties. May cause problems with sex.

  Although the front plate 10 and the back plate 20 are separable, usually radiography is performed in a combined state as shown in FIG.

  Next, cassette locking will be described. In order to keep the front plate 10 and the back plate 20 in a combined state, the cassette 1 is provided with a lock mechanism. 30a, 30b, 30c, and 30d of the back plate 20 are lock claws, and the tips of the lock claws protrude or retract from the openings 31a, 31b, 31c, and 31d in accordance with the lock ON / OFF operation. Is configured to do.

  The lock claws 32a and 32b of the back plate 20 are lock claws different from the lock claws 30a, 30b, 30c and 30d. The lock claws 32a and 32b are configured to protrude or retract from the openings 33a and 33b in accordance with the lock ON / OFF operation.

  The lock ON state refers to a state in which the tips of the lock claws 30a, 30b, 30c, and 30d protrude outward from the back plate side surface 211. At this time, the tip of the lock claw is in a state of entering the front plate 10. The lock OFF state refers to a state in which the tips of the lock claws 30a, 30b, 30c, and 30d enter inside the openings 31a, 31b, 31c, and 31d.

  In addition, when the cassette 1 is in the lock ON state, if the rod-shaped member 900 is inserted and pushed once in the direction of the arrow P from the insertion hole 34, the cassette 1 shifts to the lock OFF state, and the front plate 10 and the back plate 20 are separated. It becomes possible. Next, unless the rod-shaped member 900 is acted from the insertion hole 34, this lock OFF state is continuously maintained. Further, when the rod-shaped member 900 is inserted from the insertion hole 34 only once in the direction of the arrow P and pushed in the lock OFF state, the connecting member 35 stops in a state where it has moved by a predetermined distance in the direction of the arrow Q1 and is locked. Transition to the ON state. That is, when the rod-shaped member 900 is inserted and pushed once in the direction of arrow P from the insertion hole 34 in the lock OFF state, the lock plate is shifted to the ON state, and the front plate 10 and the back plate 20 cannot be separated. It becomes. Next, unless the rod-shaped member 900 is acted from the insertion hole 34, this lock ON state is continuously maintained.

  As described above, the cassette 1 of this embodiment employs a system (push / latch system) in which the lock ON state / lock OFF state is switched each time the rod-shaped member 900 is inserted through the insertion hole 34 and pushed. The push-latch method is well known as a mechanism used when a ballpoint pen core is taken in and out of the ballpoint pen exterior.

  FIG. 3 is a diagram showing an embodiment of the image reading apparatus.

  The apparatus main body 2 is provided with a cassette insertion port 3 and a cassette discharge port 4. The apparatus main body 2 includes two units, a main body 2a and a cassette insertion / ejection unit 2b. The cassette insertion / ejection unit 2b has a structure that can be easily detached from the main body 2a. Further, an anti-vibration rubber 73 is disposed between the main body 2a and the cassette insertion / ejection portion 2b, so that vibration at the time of cassette insertion / extraction is not easily transmitted to the main body 2a.

  Further, the sub-scanning unit 50 and the conveying unit 40 in the main body 2a are constructed on the same substrate 71. By arranging the anti-vibration rubber 72 between the substrate 71 and the bottom plate 70, an anti-vibration structure that does not propagate the vibration of the cassette insertion / discharge unit 2b to the sub-scanning unit 50 is realized.

  Further, an anti-vibration rubber 74 is disposed between the upper end of the sub-scanning unit 50 and a device frame (not shown), and the anti-vibration structure for the sub-scanning unit 50 is reinforced. With such an anti-vibration structure, the cassette 2 is inserted into the insertion port 3 while the image information is being read from the photostimulable phosphor sheet 28 by the main body 2a, and the cassette is taken out from the discharge port 4. Even if the main body 2 is vibrated, it is possible to prevent noise caused by vibration in the read image information.

  In addition, since the sub-scanning unit 50 and the transport unit 40 are constructed on the same substrate 71, the transfer position is blurred when the back plate 20 is transferred from the transport unit 40 to the sub-scanning unit 50, as will be described later. There is no. Thereby, the separation | separation of the front board 10 and the back board 20, and the union | combination operation | work can be implemented stably and accurately.

  Next, the operation of the image reading apparatus according to the present invention will be described with reference to FIGS.

  As shown in FIG. 3, the cassette 1 on which the radiographic imaging has been performed is inserted into the insertion port 3 in the direction of the arrow A1. At this time, it inserts so that the insertion hole 34 may be on the lower side and the front plate 13 of the front plate 10 faces obliquely downward. That is, the stimulable phosphor sheet 28 is inserted so that the reading surface faces obliquely downward. When the cassette 1 is inserted into the insertion port 3, the presence of the cassette 1 is recognized by a cassette detection sensor (not shown), and the cassette 1 is inserted into the insertion port 3 by the width adjusting means 47 arranged in the insertion port 3. Widened to the center.

  When the cassette 1 is brought close to the center of the insertion slot 3, the code attached to the back surface of the back plate 2 is read by the code reading means 45.

  When the code reading means 45 reads the code correctly, the cassette size is detected from the read code, and the adjustment of the width of the conveying means 40 is started according to the cassette size. That is, the width adjusting means 401a and 401b in FIG. 4 start moving in the direction of the arrow M in accordance with the size of the cassette 1.

  Next, the insertion roller 42 is operated to take the cassette 1 into the apparatus main body 2 along the dotted line a in the direction of the arrow A2. The transport means 40 is already waiting at the position of the dotted line a when the insertion roller 42 is operated, and receives the cassette 1 carried by the insertion roller 42 from the insertion port 3. When the cassette grips 402a, 402b on the lifting platform 402 (operating along the transport means 40) catch the lower end of the cassette 1, the lifting platform 402 transports the cassette 1 along the transport means 40 in the direction of arrow A2, The upper end of the cassette 1 is controlled to stop at the position indicated by the arrow Z in FIGS.

  FIG. 5 is a diagram showing the positional relationship between different cassette sizes on the conveying means 40. 1A is a half-cut cassette, 1B is a large-size cassette, 1C is a large four-size cassette, 1D is a four-cut cassette, 1E is a six-cut cassette, 1Fa is a 24x30cm size cassette, and 1Fb is a 24x30cm size A cassette for mammography, 1Ga is an 18 × 24 cm size cassette, 1Gb is an 18 × 24 cm size mammography cassette, and 1H is a 15 × 30 cm size dental cassette. Regardless of the size of all the cassettes, the position of the lifting platform 402 is controlled so that the upper end of the cassette is at the position of the arrow Z. In this way, the method of controlling the upper end of the cassette 1 so as to always stop at the same place of the conveying means 40 is called upper reference control.

  The advantages of the upper reference control are the following two points.

  1) Since the time for the sub-scanning unit 50 to transport the back plate 20 to the reading position B can be minimized regardless of the cassette size, the processing capability (throughput) of the apparatus can be improved.

  2) Since the cassette tip (upper end) can be protruded from the sub-scanning moving plate 53 by the same distance regardless of the cassette size (see FIGS. 4 and 5), the tip detection and side of the cassette 1 as described later Edge detection (see FIG. 7) can be performed. Thereby, the reading area of the photostimulable phosphor sheet 28 can be determined with high accuracy. In addition, it is possible to construct a rough and inexpensive mechanism by reducing the conveyance accuracy of the cassette 1 by the conveyance unit 40 and the accuracy of delivery of the back plate 20 from the conveyance unit 40 to the sub-scanning unit 50.

  Of course, the lower reference control, that is, a method of controlling the position of the cassette lifting platform 402 so that the lower end of the cassette 1 always stops at the same place may be adopted. One advantage cannot be gained.

  A dotted line V in FIG. 5 is a center line of the sub-scanning moving plate 53. The width adjusting means 401a and 401b are controlled so that the centers of all the cassettes are aligned with the center line of the sub-scanning moving plate 53. This is called center-based control.

  Usually, when a film is transported or the photostimulable phosphor sheet 28 is transported, one-side reference control is performed in which the film or the photostimulable phosphor sheet 28 is transported toward one side. In the case of this embodiment, since the transport means 40 and the sub-scanning unit 50 must handle the cassette 1 and the back plate 20 of various sizes, the horizontal center of gravity of the cassette 1 and the back plate 20 is controlled in one-side reference control. The position does not match the center of the sub-scanning moving plate 53 or the lifting platform 402, and the balance of sub-scanning and conveyance is lost. Furthermore, since the cassette 1 and the back plate 20 are objects that are considerably heavier than the film and the photostimulable phosphor sheet 28, the poor balance of the control on one side is not preferable in terms of reliability and stability. . Therefore, center reference control is preferred in this embodiment.

  Further, when the back plate 20 is delivered between the transport means 40 and the sub-scanning unit 50, the cassette grips 402a and 402b and the sub-scanning moving plate 53 (or the rubber magnet 54) interfere with each other to avoid this. As a measure, interference avoidance openings 540a and 540b are provided in the sub-scanning moving plate 53. In the one-side reference control, the positions of the interference avoidance openings 540a and 540b cannot be specified, and a more complicated mechanism is required. In this sense, the center reference control is preferable in this embodiment.

  Although the center reference control is employed in this embodiment, the essence of the present invention is not impaired even if the one-side reference control that avoids the above problem is performed.

  When the cassette 1 stops in accordance with the upper reference control, the tips of the grip claws 403a and 403b are inserted into the recesses of the grip recesses 16a and 16b existing on the front plate side surface 110, and the front plate 10 is moved with respect to the conveying means 40. Keep it fixed.

  The conveying means 40 has a rotating shaft 404, and can freely rotate and move at least in the range from the dotted line a to the dotted line c (the range of the angle θ) with the rotating shaft 404 as the rotation center. When the cassette 1 is taken into the apparatus main body 2 by the conveying means 40, the conveying means 40 rotates from the position of the dotted line a to the position of the dotted line c in the direction of the arrow A3 with the rotation shaft 404 as the rotation center. When the conveying means 40 rotates to the position of the dotted line c, the back surface of the back plate 20 of the cassette 1 having a ferromagnetic material is attracted to the rubber magnet 54 by magnetic force.

  FIG. 4 shows a state in which the back surface of the back plate 20 of the cassette 1 is attracted to the rubber magnet 54 by a magnetic force. In the present embodiment, a six-cut cassette is assumed. The width adjusting means 401a and 401b adjust the cassette 1 having a six-cut size to the center reference. The width adjusting means 401a and 401b, the lock pin 402c, and the lifting platform 402 do not protrude toward the sub-scanning moving plate 53 side from the back surface of the back plate 20 of the cassette 1 so as not to interfere with the sub-scanning moving plate 53. It is designed as follows. In order to avoid interference between the cassette grips 402a and 402b and the sub-scanning moving plate 53 (or the rubber magnet 54), interference avoiding openings 540a and 540b are provided in the sub-scanning moving plate 53.

  A lock pin 402c for turning ON / OFF the lock mechanism of the cassette 1 is disposed on the lifting platform 402, and the lock mechanism of the cassette 1 can be turned ON / OFF by moving the lock pin 402c up and down. . Further, the upper end (upper reference position Z) of the cassette 1 projects upward from the sub-scanning moving plate 53 of the sub-scanning unit 50 for the purpose of detecting the upper end or the side end of the cassette 1 during sub-scanning. Is configured to do.

  The sub-scanning unit 50 includes a sub-scanning rail 51, sub-scanning movable units 52a and 52b, a sub-scanning moving plate 53, and a rubber magnet 54. The sub-scanning moving plate 53 is fixed to the sub-scanning movable portions 52a and 52b, and is configured so that the sub-scanning moving plate 53 can move up and down on the sub-scanning rail 51 by a driving unit (not shown). . As the sub-scanning rail 51, a linear guide or a linear bearing guide having high conveyance performance can be used.

  In this embodiment, the rubber magnet 54 is a permanent magnet having a predetermined area. As shown in FIG. 4, the rubber magnet may have one sheet having interference avoiding openings 540a and 540b attached to the entire surface of the sub-scanning moving plate 53, or the rubber magnet may be divided into a predetermined number to move in the sub-scanning direction. You may affix on the board 53. FIG. Further, the rubber magnet can take any shape. Also, permanent magnets or electromagnets other than rubber magnets can be used.

  The surface portion of the rubber magnet 54 that adsorbs the back surface of the back plate 20 has high flatness, and when the rubber magnet 54 adsorbs the back surface of the back plate 20, the ferromagnetic surface of the back surface of the back plate 20 is the surface of the rubber magnet 54. By following the plane, it is considered that the reading surface of the photostimulable phosphor sheet 28 is as complete as possible. Therefore, even when the back plate 20 is deformed or warped, when the back surface of the back plate 20 is attracted to the rubber magnet 54, the deformation or warpage is corrected, and the reading surface of the photostimulable phosphor sheet 28 is corrected. Can ensure flatness.

  When the back plate 20 is attracted to the rubber magnet 54, the lock pin 402c housed in the lifting platform 402 rises, and the tip of the lock pin 402c is inserted into the insertion hole 34 of the front plate 10 (see FIG. 4). ). By this operation, the lock of the cassette 1 in the lock ON state is released, and the state shifts to the lock OFF state. That is, the back plate 20 and the front plate 10 can be separated. When the cassette 1 shifts to the lock OFF state, the lock pin 402c is lowered and stored in the lifting platform 402 again.

  When the cassette 1 is unlocked and shifts to the lock OFF state, the conveying means 40 rotates in the direction of the arrow A6 and stops at the retracted position (for example, the position of the dotted line b). By this operation, the back plate 20 and the front plate 10 are completely separated.

  FIG. 6 is a view showing a state in which the back plate 20 and the front plate 10 are completely separated and the conveying means 40 is stopped at the retracted position. The cassette 1 assumes a half-cut cassette. By retracting the front plate 10 from the back plate 20 at a sufficient angle, it is possible to prevent the back plate 20 and the front plate 10 from interfering when the back plate 20 performs a sub-scanning operation. In this way, means for performing a series of operations for separating the back plate 20 and the front plate 10 are collectively referred to as separation means.

  When the back plate 20 is completely separated from the front plate 10 by the separating means, a drive unit (not shown) is operated, and the back plate 20 is conveyed (sub-scanned) in the direction of arrow A4 (upward). During the sub-scanning operation, the photostimulable phosphor sheet 28 is main-scanned in the direction perpendicular to the sub-scanning direction by the laser light R emitted from the laser scanning unit 61.

  When laser light acts on the photostimulable phosphor sheet 28, photostimulated light (image information) proportional to the radiation energy accumulated in the photostimulable phosphor sheet 28 is emitted, and this photostimulated light passes through the light guide 62. It is collected in the condenser 63 through. A photoelectric conversion element such as a photomultiplier (not shown) is disposed on the end face of the condenser tube, and converts the condensed light that has been collected into an electrical signal. The photostimulated light converted into the electrical signal is subjected to predetermined signal processing as image data, and then is transmitted from the apparatus main body 2 via a communication cable (not shown) to an operation terminal, an image storage device, an image display device, and a dry imager. Or the like (not shown).

  In this way, a means for reading image information, which includes the laser scanning unit 61, the light guide 62, the condenser 63, the photoelectric conversion element, and the like, is defined as the reading means 60. It goes without saying that the reading means 60 may be achieved by a configuration other than this embodiment as long as it reads image information from the photostimulable phosphor sheet 28.

  It is preferable that the image data capturing start time is determined by detecting the upper end of the back plate 20 with the sensor 90. When the back plate 20 is not present, the sensor 90 receives the laser light R and continues to output a signal having a predetermined intensity. However, when the upper end of the back plate 20 moves to a position where the laser light R is blocked, the sensor 90 Since the signal strength of the electrical signal output from the lowering of the back plate 20 is reduced, the upper end of the back plate 20 can be detected. Moreover, you may comprise so that the side edge of the back board 20 may be detected with a mechanism like FIG. FIG. 7A1 is a diagram showing a state in which the back plate 20 has not reached the scanning position of the laser light R. FIG. A rod 91 is connected to the light receiving surface of the sensor 90, and the laser beam R reaches the sensor 90 through the rod 91. The laser light reaching the sensor 90 is photoelectrically converted by the sensor 90 and output as an electrical signal.

  The rod 91 is, for example, a hollow tube having an opening for introducing the laser beam R, and at least an inner wall portion of the tube on which the laser beam R directly acts is coated with a substance that diffuses light. is there. The rod 91 is, for example, a rod-shaped plastic member or glass member, and a material that reflects or diffuses light is applied to the outer wall other than the opening for introducing the laser light R.

  FIG. 7B1 is a diagram illustrating the signal strength of the electrical signal output from the sensor 90 in the state illustrated in FIG. The signal intensity rises at time T0, gradually decreases with time, and disappears at time T2, that is, at the time when the laser light R passes through the right end of the rod 91.

  FIG. 7A2 is a diagram at the moment when the upper end of the back plate 20 reaches the scanning position of the laser beam R. FIG. The signal intensity of the electrical signal output from the sensor 90 at this time is represented by FIG. 7 (B2). The signal intensity rises at time T0, but sharply decreases at time T1, that is, when the laser light R passes through the left end of the cassette 1. Accordingly, if the time T1 is detected by signal processing or the like, it is possible to detect the side end of the cassette 1 (the left end in the case of the present embodiment), thereby controlling the Hsync of the laser beam and the generation timing of the image data. Can be calculated.

  Thus, if the upper end and the side edge of the back plate 20 can be detected, the reading area of the photostimulable phosphor sheet 28 can be determined with high accuracy. Further, by using such detection means at the end of the back plate 20, the conveyance accuracy of the cassette 1 by the conveyance device 40 and the delivery accuracy of the back plate 20 from the conveyance device 40 to the sub-scanning unit 50 are reduced, and rough. And an inexpensive mechanism can be constructed.

  Further, it is desirable that the laser intensity when detecting the upper end and the side edge of the back plate 20 is smaller than the laser intensity when reading the photostimulable phosphor sheet 28. The reason is that the laser light is reflected inside the apparatus and excites the photostimulable phosphor sheet 28 that has not yet started reading.

  When reading of the image information from the photostimulable phosphor sheet 28 is completed, a drive unit (not shown) starts conveying the back plate 20 in the direction of arrow A5 (downward). While the back plate 20 is conveyed in the direction of the arrow A5, the erasing light C is emitted from the erasing means 64, and the image information remaining on the photostimulable phosphor sheet 28 is erased. As the erasing lamp used in the erasing means 64, a halogen lamp, a high-intensity fluorescent lamp, an LED array, or the like can be used.

  As described above, in this embodiment, the image information is read in the forward path (upward conveyance) of the sub-scanning unit 50, and the image information remaining in the backward path (downward conveyance) of the sub-scanning unit 50 is read. Since erasing is performed, the time required for the reciprocating motion of the sub-scanning unit 50 can be used effectively without wasting it. Thereby, the processing capability (throughput) of the radiation image reading apparatus can be improved.

  Further, in this embodiment, since the erasing unit 64 is arranged at the lower stage in the vertical direction of the reading unit 60, the moving direction of the sub-scanning unit 50 is immediately changed to the backward direction (downward) when the reading operation of the image information by the reading unit 60 is completed. Direction). As a result, the erasing operation can be started without loss of time during the reciprocating motion of the sub-scanning unit 50, so that the processing capability (throughput) of the radiation image reading apparatus can be further improved.

  In addition, since the erasing unit 64 is arranged at the lower stage in the vertical direction of the reading unit 60, the lower end of the back plate 20 does not pass through the reading position B of the reading unit 60. It is possible to prevent an accident that the back plate cannot be lowered due to interference with the light collecting member. For this reason, it becomes possible to improve the reliability and stability of the apparatus.

  When the back plate 20 is lowered to the position delivered to the rubber magnet 54, the drive unit (not shown) stops the movement of the back plate 20 by the sub-scanning unit 50. When the back plate 20 stops at the position where it is delivered to the rubber magnet 54, the conveying means 40 that has been retracted to the retracted position rotates again to the position of the dotted line c, and the back plate 20 and the front plate 10 are united. . When the back plate 20 and the front plate 10 are combined, the lock pin 402c stored in the lifting platform 402 is raised, and the tip of the lock pin 402c is inserted into the insertion hole 34 of the front plate 10. By this operation, the cassette 1 that has been in the lock OFF state is locked, and shifts to the lock ON state. That is, the back plate 20 and the front plate 10 cannot be separated. When the cassette 1 shifts to the lock ON state, the lock pin 402c is lowered and stored in the lifting platform 402 again. In this way, means for performing a series of operations for shifting the lock state of the cassette 1 from the lock OFF state to the lock ON state are collectively referred to as a coalescing means.

  When the uniting operation of the back plate 20 and the front plate 10 is completed by the uniting means, the conveying unit 40 again rotates in the direction of the arrow A6 to the position of the dotted line b and stops. In this way, the operation of peeling off the back plate 20 (cassette 1) from the rubber magnet 54 is performed with rotational movement, and therefore the back plate 20 (cassette 1) with a small force compared to the case of peeling off by parallel movement. Can be peeled off from the rubber magnet 54.

  When the conveying means 40 stops at the position of the dotted line b, the fixed state of the front plate 10 by the grip claws 403a and 403b is released, and the cassette 1 becomes capable of being conveyed on the conveying means 40.

  When the fixed state of the front plate 10 is released, the lifting platform 402 conveys the cassette 1 in the direction of the discharge port 4 along the conveying means 40, and delivers the cassette 1 to the discharge roller 43. When the discharge roller 43 receives the cassette 1, the discharge roller 43 performs a discharge operation until the cassette 1 is completely discharged to the discharge port 4. When the cassette 1 is completely discharged to the discharge port 4, the transport means 40 rotates and moves to the position of the dotted line “a” in the direction of the arrow A 6, and shifts to a state in which the next cassette 1 can be received.

  In this embodiment, it has a stacker part in which about 2 to 5 cassettes 1 can be stacked in the discharge port 4. When the position of the cassette 1 immediately after moving in the direction of the arrow A7 and completing the discharge to the discharge port 4 is represented by 1a, the cassette 1 discharged to the place 1a is removed from the upper end of the cassette 1 by its own weight. It falls in the direction of arrow A8 and finally moves to the position represented by 1b. The bottom plate portion of the discharge port 4 is inclined from the 1a side to the 1b side so that this operation is performed only by the own weight of the cassette 1. Further, in order to reliably transport the cassette 1 from the 1a side to the 1b side, for example, a transport mechanism 44 that transports the lower portion of the cassette 1 in the direction of the arrow A8 is provided, and the entire cassette 1 extends from the position 1a to the position 1b. You may make it comprise so that it may move reliably. Since the discharge port 4 is configured so that about 2 to 5 discharge cassettes 1 can be stacked, the user can remove the discharge cassette 1 until the discharge port 4 is filled with the discharge cassette 1, Sequentially inserted cassettes 1 can be inserted into the insertion slot 3. In general, radiographic imaging uses 1 to 5 cassettes in average, and about 1.8 on average, so the outlet 4 can be configured to stack about 2 to 5 cassettes 1 discharged. By doing so, the user is less troubled with the removal of the discharged cassette 1 during the inspection, and the work can be performed efficiently.

  The conveying means 40 in this embodiment is configured to separate the front plate 10 and the back plate 20 after the back surface of the back plate 20 is attracted to the rubber magnet 54. However, the front plate 10 and the back plate 20 are separated. After that, the back plate 20 may be configured such that the back surface of the back plate 20 is attracted to the rubber magnet 54.

  In addition, the front plate 10 and the back plate 20 are separated after the cassette 1 is rotated, but after the front plate 10 and the back plate 20 are separated, only the back plate 20 is rotated. May be. In addition, the back plate 20 and the photostimulable phosphor sheet 28 are delivered to the sub-scanning unit 50 by the rotation of the conveying unit 40. However, a part or the whole of the sub-scanning moving plate 53 is rotated and moved. By doing so, the back plate 20 and the photostimulable phosphor sheet 28 may be delivered to the sub-scanning unit 50.

  Next, the sub-scanning unit 50 will be described with reference to FIG. FIG. 2 is a partially transparent perspective view showing the transport mechanism in the sub-scanning unit 50. In FIG. 2, the back plate 20 has a ferromagnetic portion made of iron or the like on a part of the attachment surface side, and a rubber magnet 54 or a permanent magnet is attached to the attachment surface of the support, such as a double-sided tape or an adhesive. Is attached by adsorption to the sub-scanning moving plate 53 attached by the magnetic force.

Further, a linear sub-scanning rail 51 fixed in the vertical direction to a frame (not shown) is engaged with and guided by the back surface of the support of the sub-scanning moving plate 53. The drive pulley 459 is connected to a motor 453 fixed to a frame (not shown) via a direct drive and coupling 452. Further, when there is a restriction on the motor speed, a reduction mechanism 450 including a motor pulley 454 and an endless belt 458 may be provided between the motor 453 and the drive pulley 459. FIG. It shows about the case where a mechanism is used. In the speed reduction mechanism of this embodiment, the drive pulley 459 and the motor pulley 454 are preferably made of stainless steel, and the endless belt 458 is made of a material having a Young's modulus of 1.5 kgf / mm ² or more. Then, it is made of nickel.

  One end of one belt 440 is connected to the upper end of the sub-scanning moving plate 53, and the other end of the belt is connected to the counterweight 460 via a pulley that is freely attached to a frame (not shown). Connected to the top. The mass of the counterweight 460 is substantially equal to the total mass of the lightest plate and the sub-scanning moving plate 53 when there are a plurality of types of back plates 20. Further, when the sub-scanning moving plate 53 moves upward, the counterweight 460 moves downward, so that the moving direction is opposite.

  Next, the operation of the reading unit in this embodiment will be described. A laser beam is deflected and scanned from the laser scanning unit 61 and emitted, and is irradiated onto the photostimulable phosphor plate 28 provided on the back plate 20. At this time, since a light emission phenomenon occurs according to the latent image from the photostimulable phosphor layer on the surface of the photostimulable phosphor plate 28, the light is condensed by the condenser 63, subjected to photoelectric conversion, and signal processing. Read the image.

  On the other hand, the motor 453 rotates the driving pulley 459 at a constant speed, but the driving force from the motor 453 is generated by the friction force through the coupling 452, the endless belt 458, and the speed reduction mechanism 450 using the motor pulley 454. Communicated. Further, the endless belt 458 is maintained at a predetermined tension by a tension adjusting mechanism (not shown) in order to ensure not only power transmission of the speed reduction mechanism but also precise constant speed control and positioning accuracy. When there is no restriction on the motor rotation speed, the output shaft of the motor 453 may be arranged on the same axis as the rotation shaft of the drive pulley 459 and directly connected using a coupling or the like.

  The driving pulley 459 that rotates at a constant speed is driven by the frictional force of the belt 440 that is in contact therewith, and thereby the back plate 20 together with the sub-scanning moving plate 53 that is precisely guided in the vertical direction by the sub-scanning rail 51. Moves upward so that the entire surface of the back plate 20 can be scanned. When erasing the latent image, if the erasing means 64 is below the main scanning portion, the motor 453 is rotated in the opposite direction to that during reading, and the sub-scanning moving plate 53 is moved downward. Further, when the erasing means 64 is above the main scanning portion, it may be erased immediately after reading the image, or the stimulable fluorescent plate may be moved downward during reading and moved upward during erasing. good.

  Further, when driving the belt 440, a drive pulley 459 and a backup roller 451 that does not have a drive paired with the drive pulley 459 may be provided, and thereby the belt 440 is configured to be crimped and sandwiched. Since the pulley can increase the frictional force between the belts, the use of a backup roller can aim to further improve the conveyance accuracy. The belt 440 is driven by being guided by a guide pulley 470.

The belt 440 to be used is preferably formed of a material having a Young's modulus of 1.5 kgf / mm ² or more, and a metal belt, a metal wire, a resin belt, or the like is used. You may hang in parallel by composition. One belt may be arranged on the center line in the sub-scanning direction, or a plurality of belts may be arranged at positions symmetrical with respect to the center line.

  One linear guide may be arranged on the center line in the sub-scanning direction, or a plurality of linear guides may be arranged in a line symmetrical position with respect to the center line. This is preferable because the time required for adjustment can be reduced. Furthermore, the arrangement of only one linear motion guide is more preferable because it is not necessary to substantially adjust the parallelism between the plurality of linear motion guides. Further, the usage quantities of the belt and the linear guide can be freely selected as necessary.

  Further, a counterweight 460 having a mass substantially equal to the total mass of the back plate 20 and the sub-scanning moving plate 53 is connected to the sub-scanning moving plate 53 via a belt 440 and fixed to a frame (not shown). Fixed and guided. Further, since the sub-scanning moving plate 53 is driven in the direction opposite to the moving direction of the sub-scanning moving plate 53, the inertia of the back plate 20 and the sub-scanning moving plate 53 can be offset, and the sub-scanning moving plate 53 The driving reaction force during the movement of 53 can be kept small. In this embodiment, the movement direction of the sub-scanning moving plate 53 is the anti-gravity direction, so that the burden on starting the motor 453 can be reduced when the sub-scanning moving plate 53 is moved in the lifting direction. . Next, the effect of the counterweight 460 will be described. When there are a plurality of types of back plates 20, the sub-scanning moving plate 53 and the back plate 20 can be combined with the back plate 20 when the mass of the counterweight 460 is made equal to the total weight of the lightest back plate 20 and the sub-scanning moving plate 53. Compared with a case where a counterweight is not formed when lifting, the load applied when starting the motor 453 is obviously reduced, which can contribute to miniaturization of the motor to be used.

  Further, during the reading operation that requires the most constant speed accuracy, the back plate 20 and the sub-scanning moving plate 53 are moved while keeping a constant load on the motor 453. Desirably, there may be a configuration in which the total mass of the back plate 20 and the sub-scanning moving plate 53 is different from the mass of the counterweight 460. In that case, either the suction plate portion or the counterweight will be urged in the direction of gravity, and as a result, the motor 453 is always in the constant speed rotation except when the motor 453 is started and stopped. As a result, a constant load is applied, which enables precise constant speed control and accurate positioning.

  When the total mass of the back plate 20 and the sub-scanning moving plate 53 is lighter than the mass of the counterweight 460, it is effective when the stimulable fluorescent plate is moved upward at the time of reading. When the total mass of the sub-scanning moving plate 53 is heavier than the mass of the counterweight 460, it is effective when the stimulable fluorescent plate is moved downward during reading.

  Therefore, a difference is made between the total mass of the back plate 20 and the sub-scanning moving plate 53 and the mass of the counterweight 460, but by making the difference small, the motor can be miniaturized and precise. This is desirable because the effects of both constant speed control and accurate positioning can be obtained. Furthermore, in the case where there are a plurality of types of back plates 20, the total mass of the lightest back plate 20 and sub-scanning moving plate 53 is balanced. It is more desirable to reduce the mass of the weight 460 or to make the mass of the counterweight 460 heavier than the total mass of the back plate 20 and the sub-scanning moving plate 53 with the heaviest weight.

  Further, in this apparatus, when viewed from the surface direction of the sub-scanning moving plate 53 along the moving direction of the sub-scanning moving plate 53, the center line of the moving direction (that is, in this embodiment, the sub-scanning moving plate 53 The back plate 20 is held at a line symmetrical position with respect to the vertical center line when viewed from the plane side.

  Further, a sub-scanning rail 51 for guiding the sub-scanning moving plate 53 is provided. When viewed from the image forming surface direction of the back plate 20, the center line in the vertical movement direction of the sub-scanning rail 51 is the back plate 20. And the sub-scanning moving plate 53 is configured to pass through the center of gravity (that is, on the center line in the vertical direction of the sub-scanning moving plate 53 because the sub-scanning moving plate 53 is symmetrical in this embodiment). This is preferable because the sub-scanning moving plate 53 and the back plate 20 can be guided while the weight balance is good. Furthermore, considering the assembly time, when only one belt is configured, it goes without saying that the assembly time is shorter than when multiple belts are configured in parallel, and between the multiple belts. There is virtually no need to take into account possible adverse effects due to component accuracy or assembly errors. As a result, requirements for component accuracy and assembly accuracy can be relaxed, which is more preferable. Similarly, considering the assembly time of the linear motion guides, it is preferable that the number of linear motion guides is small because the time required for adjusting the parallelism can be reduced. Furthermore, it is more preferable to configure the linear guide with only one, since it is not necessary to substantially adjust the parallelism that occurs when the linear guides are configured in parallel.

  A counterweight 460 having substantially the same mass as that of the sub-scanning moving plate 53 and the suction plate is fixed to both ends of the belt 440, and the belt 440 can be maintained at an appropriate tension by using the mass. As a result, the frictional force between the pulley and the belt is increased, and precise constant speed control and accurate positioning are possible. The belt 440 is preferably a steel belt made of stainless steel, which has extremely low elasticity among belt materials, because it can achieve improved conveyance accuracy. A wire, a resin belt, etc. may be used and it is good also as a structure which combined them.

  Furthermore, since the frictional force between the pulley and the belt can be increased by providing the backup roller 451, the drive transmission performance at the belt can be maintained higher, and by increasing the frictional force between the pulley and the belt, Since the sub-scanning moving plate 53 and the counterweight 460 can be reduced in weight, the overall weight of the apparatus can be reduced.

  By transmitting the drive between the motor 453 and the drive pulley 459 using the speed reduction mechanism 450 using the motor pulley 454 and the endless belt 458, the reduction ratio can be configured in an arbitrary state, so that the vibration frequency band of the motor rotation Can be easily designed so as not to affect the natural frequency of the apparatus, thereby achieving precise constant speed control and improved positioning accuracy, thereby contributing to the improvement of the diagnostic image quality. Further, for the endless belt 458 in this embodiment, a nickel electroformed belt is used from the viewpoint of ease of parts manufacture and stability of part accuracy, but other metal or resin belts such as stainless steel are used. May be used.

  The belt 440 is connected to one end 440a of the belt 440 serving as a transmission unit and the holding unit side coupling unit 600 of the sub-scanning moving plate 53 serving as a holding unit, or the weight side coupling unit 700 between the other end 440b of the belt 440 and the counterweight 460. It is connected so that it can rotate in the meandering direction. Since the holding means side connecting portion 600 and the weight side connecting portion 700 are configured similarly, only the holding means side connecting portion 600 will be described in detail with reference to FIGS. 8 is a front view showing the holding means side connecting portion and the sub-scanning movable portion, FIG. 9 is a side view showing the holding means side connecting portion and the sub-scanning movable portion, and FIG. 10 shows the holding means-side connecting portion and the sub-scanning movable portion. FIG. 11 is a view showing a connecting member of the holding means side connecting portion.

  The holding means side connecting portion 600 of this embodiment includes a connecting fulcrum shaft 601, a pair of connecting fulcrum plates 602a and 602b, a receiving means 603, a bearing 604, a pair of collars 605a and 605b, and a washer 606. Have. The bearing 604 includes an outer ring 604a, an inner ring 604b, and a ball 604c.

  The connecting fulcrum shaft 601 has small-diameter fulcrum shaft portions 601a1 and 601a2 at both ends, and has a mounting surface 601b formed by cutting out a concave shape at the center, and a mounting female at the center in the axial direction of the mounting surface 601b. A screw hole 601c is formed. The connection fulcrum shaft 601 is made of stainless steel, but other metal or resin may be used. The pair of connection fulcrum plates 602a and 602b are formed in an L shape, and include attachment portions 602a1 and 602b1, and connection portions 602a2 and 602b2. The pair of connection fulcrum plates 602a and 602b are made of stainless steel, but other metals or resins may be used. The pair of connection fulcrum plates 602a and 602b oppose the connection parts 602a2 and 602b2 with a predetermined interval capable of supporting the connection fulcrum shaft 601, and the attachment parts 602a1 and 602b1 are moved to the sub-scanning movable part 52a by the pair of screws 610a and 610b. The upper part 52a1 is fastened and fixed.

  The fulcrum shaft portions 601a1 and 601a2 at both ends of the connection fulcrum shaft 601 are rotatably connected to the connection portions 602a2 and 602b2 of the connection fulcrum plates 602a and 602b arranged opposite to each other through bearings 611a and 611b, respectively. ing. The connection fulcrum shaft 601 is smoothly supported by the connection fulcrum plate 602 by bearings 611a and 611b. As the bearings 611a and 611b, ball bearings including outer rings 611a1 and 611b1, inner rings 611a2 and 611b2, and balls 611a3 and 611b3 are used, but thrust bearings or the like may be used.

  The receiving means 603 has a male screw portion 603a and a head portion 603b, and is made of a metal such as stainless steel. An annular recess 603b1 is formed inside the head 603b, and a tool engagement groove 603b2 is formed outside.

  One end portion 440a of the belt 440 is provided with folded portions 440a1 and 440a2 on the left and right sides of the tip. The folded portions 440a1 and 440a2 serve as mounting guides, and the one end portion 440a of the belt 440 is reinforced to make it difficult to bend. Yes. The one end 440a of the belt 440 has a mounting hole 440a3 formed at the center, and the bearing 604 is assembled to the mounting hole 440a3. In assembling the bearing 604, the outer ring 604a is fixed to the mounting hole 440a3.

  As shown in FIG. 10, one end 440a of the belt 440 is applied to the mounting surface 601b of the connection fulcrum shaft 601, and the bearing 604 of the belt 440 is positioned in the mounting female screw hole 601c of the mounting surface 601b via the collar 605a. To do. In this state, the male threaded portion 603a of the receiving means 603 is inserted through the collar 605b and the washer 606, and further inserted into the bearing 604 and the collar 605a, and the tool is engaged with the head 603b of the receiving means 603 so that the male screw is engaged. The portion 603a is screwed into the mounting female screw hole 601c. When the receiving means 603 is screwed, the washer 606, the collar 605b, and the bearing 604 are positioned in the annular recess 603b1, and the washer 606, the collar 605b, and the bearing 604 are protected by the receiving means 603.

  In this embodiment, the belt 440 is supported by the drive pulley 459, the guide pulley 470, and the like. However, when the belt 440 is driven, the belt 440 may meander. Thus, when meandering to the belt 440, as shown in FIG. 8, the one end portion 440a of the belt 440 is rotated by the bearing 604 in the direction of the arrow with the male screw portion 603a of the receiving means 603 as a fulcrum, and the sub-scanning movable portion 52a. Not transmitted to.

  Clearances 910a and 910b are formed between the folded portions 440a1 and 440a2 of the belt 440 and the side walls 601b1 and 601b2 of the mounting surface 601b formed by cutting out in a concave shape, and the front end portion 440d of the belt 440 and the sub-scanning movable portion 52a. A gap 911 is formed between the upper portion 52a1 of the belt 440 and the one end 440a of the belt 440 is allowed to rotate in the direction of the arrow by the bearing 604 with the receiving means 603 as a fulcrum.

  Thus, even if a meandering force is applied to the belt 440, the meandering of the belt 440 is absorbed by the holding means side connecting portion 600 and is not transmitted to the sub-scanning movable portion 52 a and the sub-scanning moving plate 53. As a result, it is possible to prevent unevenness in the feeding speed of the photostimulable fluorescent plate 28 due to meandering of the belt 440, and to obtain a good image without image unevenness. It is possible to provide. In this embodiment, meandering of the belt 440 can be absorbed by a simple structure in which the bearing 604 is inserted between the mounting hole 440a3 of the belt 440 and the receiving means 603.

  Further, when the belt 440 resonates and the one end 440a of the belt 440 swings as shown in FIG. 9, the connecting fulcrum shaft 601 uses the fulcrum shafts 601a1 and 601a2 at both ends as fulcrums via the bearings 611a and 611b. To turn. As described above, the connection fulcrum shaft 601 smoothly rotates to the connection fulcrum plate 602 by the bearings 611a and 611b, so that the resonance of the belt 440 is attenuated and the vibration in the traveling direction of the photostimulable fluorescent plate 28 is reduced. Yes.

  In this embodiment, the holding means side connecting portion 600 and the weight side connecting portion 700 are configured in the same manner. However, at least one of the holding means side connecting portion 600 and the weight side connecting portion 700 is shown in FIGS. As shown, the belt 440 serving as the transmission means may be configured so as to be rotatable in the meandering direction.

  The present invention has been described with reference to the embodiment of the present invention. However, the present invention should not be construed as being limited to the above-described embodiment, and can be changed or improved as appropriate. For example, a toothed belt may be used as the belt, and the belt may be meshed with a belt that has a pulley.

  The image reading apparatus is configured such that when the driving unit is driven, the storage phosphor moves in a direction opposite to the moving direction of the counterweight, and the stimulable phosphor sheet is main-scanned by the main scanning unit. Even when a force acts in a meandering direction on the transmission means during driving, the meander of the transmission means is absorbed by at least one of the holding means side connecting portion and the weight side connecting portion and is not transmitted to the holding means or the counterweight. Therefore, it is possible to obtain a good image without image unevenness, and to provide an image that can be diagnosed with good diagnostic efficiency.

It is a perspective view which shows the cassette used with an image reading apparatus. FIG. 6 is a partial perspective view illustrating a transport mechanism in a sub-scanning unit. 1 is a diagram illustrating an embodiment of an image reading apparatus. FIG. 6 is a diagram in which the width adjusting means starts moving in the direction of arrow M according to the size of the cassette. It is the figure which showed what kind of positional relationship a different cassette size has on a conveyance mechanism. It is a figure of the state which isolate | separated the back board and the front board completely, and the conveyance mechanism stopped in the retracted position. It is a figure which shows the signal strength of the electrical signal output from a sensor. It is a front view which shows a holding means side connection part and a subscanning movable part. It is a side view which shows a holding means side connection part and a subscanning movable part. It is a top view which shows a holding means side connection part and a subscanning movable part. It is a figure which shows the connection member of the holding means side connection part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cassette 2 Apparatus main body 2a Main body part 10 Front board 20 Back board 28 Stimulable fluorescent substance sheet 40 Conveyance mechanism 50 Subscanning part 51 Subscanning rail 53 Subscanning moving plate 61 Laser scanning unit 440 Belt 600 Holding means side connection part 601 Connection fulcrum shafts 602a, 602b A pair of connection fulcrum plates 603 Receiving means 604 Bearings 605a, 605b A pair of collars 606 Washers 700 Weight side connection part

Claims (4)

A plate-like member attached with the stimulable phosphor sheet, or a holding means for holding the stimulable phosphor sheet;
Guide means for guiding the holding means;
Driving means for driving the holding means to move;
Transmission means for moving the holding means;
Drive transmission means for transmitting the drive of the drive means to the transmission means;
A counterweight connected to the holding means via the transmission means;
Main scanning means for scanning in a direction orthogonal to the moving direction of the holding means,
When the driving means is driven, the storage means moves in the direction opposite to the moving direction of the counterweight, and the stimulable phosphor sheet is configured to be main scanned by the main scanning means,
At least one of a holding means side connecting portion between one end of the transmitting means and the holding means, or a weight side connecting portion between the other end of the transmitting means and the counterweight can be rotated in the meandering direction of the transmitting means. An image reading apparatus connected to the image reading apparatus. The holding means side connecting portion or the weight side connecting portion is
2. The image reading apparatus according to claim 1, wherein the connecting fulcrum shaft is connected to a fulcrum so as to be rotatable in a meandering direction of the transmission means via a bearing. The holding means side connecting portion or the weight side connecting portion is
A connecting fulcrum shaft supported by the holding means or the counterweight via fulcrum shafts at both ends, and having an attachment surface to which the end of the transmission means is attached;
A receiving means that is inserted into an attachment hole formed in an end portion of the transmission means, is attached to an attachment surface of the connection fulcrum shaft, and holds the end portion of the transmission means;
The image reading apparatus according to claim 1, further comprising the bearing inserted between the mounting hole of the transmission unit and the receiving unit. The image reading apparatus according to claim 1, wherein the transmission unit is a metal belt.

Images