JP2002278000A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reader which can provide an excellent image having no image unevenness and provide an image enabling diagnosis with excellent diagnosis efficiency. SOLUTION: A vibration attenuating means is arranged between a holding means which holds a plate type member with a storage phosphor sheet attached thereto or the storage phosphor sheet and a balance weight coupled with the holding means through a transmission means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a radiation image reading apparatus for reading radiation image information stored in a stimulable phosphor sheet.

[0002]

2. Description of the Related Art Radiation images such as X-ray images are widely used for diagnosing diseases. Conventionally, in order to obtain such a radiation image, X-rays that have passed through a subject are irradiated on a phosphor layer (fluorescent screen) to generate visible light, and this visible light is used to take a normal photograph. In the same manner, a so-called radiograph in which a film using a silver salt is irradiated with light and developed is used. However, in recent years, techniques have been devised for directly taking out an image from the phosphor layer without using a film coated with a silver salt. As an example of this technique, the phosphor that has passed through a subject such as a patient is absorbed by the phosphor, and then the phosphor is excited by, for example, light or thermal energy, so that the phosphor is accumulated by the absorption. There is one that emits radiation energy as fluorescent light, detects the fluorescent light, and forms an image.
Specifically, for example, U.S. Pat.
No. 5-12144 discloses a radiation image conversion method using a stimulable phosphor and using visible light or infrared light as stimulating excitation light. This method uses a stimulable phosphor sheet having a stimulable phosphor layer formed on a support, and irradiates the stimulable phosphor layer of the stimulable phosphor sheet with radiation transmitted through a subject. By accumulating radiation energy corresponding to the radiation transmittance of each part of the subject to form a latent image, and then scanning this stimulable phosphor layer with stimulating excitation light, the accumulated radiation energy of each part is emitted. Then, this is converted into light, and the intensity of the 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 the digital image data, an image is formed on a silver halide film, or an image is output to a CRT or the like and visualized. The digital image data is stored in an image storage device such as a semiconductor storage device, a magnetic storage device, and an optical disk storage device, and is then taken out of these image storage devices as needed, via a silver halide film, a CRT, an LCD, or the like. Can be visualized.

[0003] When a stimulable phosphor sheet is scanned with stimulable excitation light, the stimulable phosphor sheet and the stimulable excitation light source must be relatively moved precisely at a constant speed. For this reason, in the prior art, the stimulable phosphor sheet is driven in one direction by using a ball screw while guiding the stimulable phosphor sheet by a linear motion guide.

[0004]

However, in such a conventional technique, the vibration of the linear motion guide and the vibration of the ball screw appear as feed unevenness in the sub-scanning direction, and the accumulation property of the stimulable phosphor plate or the like is increased. When scanning the phosphor with excitation light,
In some cases, the image became uneven and the diagnostic image was hindered.

In order to solve such a problem, a belt transport system instead of a ball screw is conceivable. In this system, the vibration in the traveling direction of the stimulable phosphor plate is small, and the feeding speed unevenness is good.

However, in a low-speed conveyance state of 10 mm / s or the like, when the sliding resistance of the linear guide is large, a stick-slip phenomenon that occurs due to the relationship between the static friction and the dynamic friction of the linear guide causes a counterweight with the suction plate. , Via the belt, they are pulled against each other, and as a result, the amplitude of vibration in the traveling direction is amplified, so that the unevenness of the feeding speed of the stimulable fluorescent plate is deteriorated, and as a result, image unevenness occurs. There is a problem that the efficiency of diagnosis is reduced. The present invention has been made in view of the problems of the related art, and has as its object to obtain a good image without image unevenness. Also,
Accordingly, it is an object to provide an image which can be diagnosed with good diagnostic efficiency.

[0007]

SUMMARY OF THE INVENTION The above-mentioned object of the present invention is as follows.
This is achieved by the following apparatus. (1) a plate-like member to which the stimulable phosphor sheet is attached;
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, and driving A drive transmission means for transmitting the drive of the means to the transmission means, a counterweight connected to the holding means via the transmission means, and a main scanning means for scanning in a direction orthogonal to the moving direction of the holding means. When the driving unit is driven, the holding unit 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 unit. An image reading device, wherein vibration damping means is arranged between the holding means and the counterweight.

The plate-like member is a member to which a stimulable phosphor sheet can be attached, and is a plate-like member. Specific examples thereof include a back plate and a front plate of a cassette for a stimulable phosphor sheet, but the present invention is not limited to these, and members other than the cassette may be used.

The holding means is, for example, a means for holding a plate-like member to which a stimulable phosphor sheet is attached or a stimulable phosphor sheet, such as the sub-scanning moving plate 53 shown in the embodiment.

The transmitting means is formed of, for example, a "sheet-like or linear material" used in the definition of "B65H" of the IPC classification, such as a web or a wire such as the belt 440 described in the embodiment. Preferably, it is

It is preferable that the driving means is, for example, a means for rotationally driving like the motor 453 shown in the embodiment, but is not limited to this. In addition, the drive transmission means,
For example, the transmission may be performed by changing the speed as in the speed reduction mechanism 450 described in the embodiment, but is not limited thereto, and the drive of the driving unit may be directly transmitted to the transmission unit.

(2) The image scanning device according to (1), wherein the vibration damping means includes a roller and a spring.

(3) An image according to (1), wherein a rotation mechanism for rotating the transmission means is provided in a connecting portion between the counterweight and the transmission means in a direction substantially perpendicular to a traveling direction. Scanning device.

(4) A rotation mechanism for rotating the transmission means in a direction substantially perpendicular to the traveling direction is provided at a joint between the holding means and the transmission means (1).
An image scanning device according to claim 1.

(5) The image scanning apparatus according to (1), wherein the connecting portion of the holding means and the transmission means is rotatable about an axis substantially perpendicular to a traveling direction.

(6) The transmission means connected to the driving means, and a backup roller for improving a frictional force on a side of the transmission means opposite to the drive transmission means when the transmission means is driven by friction. The image reading device according to any one of (1) to (5), which is characterized in that:

(7) The transmitting means has a Young's modulus of 1.5 k.
The image reading device according to any one of (1) to (6), wherein the image reading device is formed of a material of gf / mm ² or more.

(8) The image reading apparatus according to any one of (1) to (7), wherein the transmission unit is a metal belt.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a perspective view showing a cassette 1 used in the radiation image reading apparatus of the present invention. The cassette 1 includes 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 such as aluminum or hard plastic that can withstand a large load during full-load photographing.
For example, aluminum and carbon fiber reinforced plastic,
It is preferable to be formed of a member having relatively small radiation absorption.

In a cassette of the type in which the side surface of the cassette is opened and closed or the side plate of the cassette is pulled out, the outer periphery of the side surface of the cassette cannot be formed with a continuous structure, so that the structure is weak against the load from the front side. ing. On the other hand, in this embodiment, since the frame 11 of the front plate 10 has a structure that covers the outer periphery of the front plate 13 without a break, the load applied from the front plate 10 side of the cassette 1 during photographing is evenly applied to the entire frame 11. Can be accepted. Therefore, the structure is extremely strong against the load applied from the front plate 10 side.

The back plate 20 is formed of a back plate main body 21, a support plate 27 having a lead foil on the back surface, and a stimulable phosphor sheet 28. The stimulable phosphor sheet 28 It is fixed to. The back plate main body 21 is preferably formed of a ferromagnetic plastic or the like so that it can be attracted to the rubber magnet 54 of FIG. 3 by magnetic force. Alternatively, the back plate main body 21 may be formed of ordinary plastic, and a ferromagnetic sheet such as an iron foil may be attached to the back plate back surface 210. Further, a method of applying a ferromagnetic substance to the back plate 210 may be used.

The back plate back surface 210 is designed so that when attracted to the rubber magnet 54, the back plate back surface 210 follows the plane formed by the rubber magnet 54. That is, the back plate 20 has a certain degree of rigidity, and has sufficient flexibility 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, for example, even if the back plate 20 is deformed or warped due to aging or usage, the back plate 20 follows the flat surface on the rubber magnet 54 side. 20 deformation and warpage are corrected. Therefore, the surface of the stimulable phosphor sheet 28 can always be kept flat when reading image information.

When a load-bearing photographing (bed photographing, full load photographing, or the like) is performed from the front plate 10 side, a situation occurs in which the front plate 13 of the front plate 10 is considerably large on the back plate 20 side. At this time, if the rigidity of the back plate 20 is too high, the back plate 20 will maintain its planarity.
Are pressed by a considerable amount from both sides, and the stimulable phosphor is damaged. 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 bent to some extent in a direction in which the back plate 20 escapes from being pressed by the front plate 20. Therefore, the stimulable phosphor is not damaged.

Of course, the back plate 20 should not have more flexibility than necessary. If the back plate 20 has more flexibility than necessary, the durability of the cassette 1 will be reduced. Also, if the back plate 20 is given more flexibility than necessary, the amount of slack of the back plate 20 due to the weight of the back plate 20 becomes large, causing a problem in light shielding properties, or a problem with the photostimulable phosphor surface during photographing. Or a problem with sex.

Although the front plate 10 and the back plate 20 are separable, radiation imaging or the like is usually performed in a united state as shown in FIG.

Next, locking of the cassette will be described.

The cassette 1 is provided with a lock mechanism to keep the front plate 10 and the back plate 20 combined. 30a, 30b, 30c, 3 of the back plate 20
Reference numeral 0d denotes a lock claw, and the tip of each lock claw has an opening 31a, 3
It is configured to protrude or retract from 1b, 31c, 31d.

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

The lock ON state means that the lock claws 30a, 3a
The state in which the tips of 0b, 30c, and 30d protrude outside the back plate side surface 211. At this time, the tip of the lock claw is in a state of protruding into the front plate 10. The lock-off state refers to a state in which the tips of the lock claws 30a, 30b, 30c, 30d enter the insides of the openings 31a, 31b, 31c, 31d.

When the cassette 1 is inserted in the insertion hole 34 only once in the direction of arrow P and pushed when the cassette 1 is in the lock ON state, the cassette 1 shifts to the lock OFF state,
The front plate 10 and the back plate 20 can be separated. Next, as long as the rod-shaped member is not actuated from the insertion hole 34, this lock-off state is maintained continuously. When the rod-shaped member is inserted only once in the direction of arrow P from the insertion hole 34 and pushed in the lock-off state, the connecting member 3
5 stops in a state where it has moved a predetermined distance in the direction of arrow Q1, and shifts to the lock ON state. That is, when the rod-shaped member is inserted only once from the insertion hole 34 in the direction of the arrow P and pushed in the lock-off state, the state shifts to the lock-on state, and the front plate 10 and the back plate 20 become inseparable. Become. Next, as long as the rod-shaped member is not actuated from the insertion hole 34, this lock ON state is continuously maintained.

As described above, the cassette 1 of this embodiment is
Employs a system (push-latch system) in which the lock ON state / lock OFF state is switched each time the rod-shaped member is inserted from the insertion hole 34 and pushed. The push-latch system is well known as a mechanism used when inserting and removing a ball-point pen core from a ball-point pen exterior.

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

The apparatus main body 2 is provided with a cassette insertion port 3 and a cassette discharge port 4. The device body 2
Is composed of two units, a main body 2a and a cassette insertion / ejection section 2b, and the cassette insertion / ejection section 2b is
It has a structure that can be easily removed from. A vibration isolating rubber 7 is provided between the main body 2a and the cassette insertion / ejection section 2b.
3 to provide a vibration-proof structure in which vibrations at the time of cassette insertion / discharge are not easily transmitted to the main body 2a.

The sub-scanning section 50 and the transport means 40 in the cassette insertion / ejection section 2b are constructed on the same substrate 71. By disposing the vibration isolating rubber 72 between the substrate 71 and the bottom plate 70, a vibration isolating structure that does not allow the vibration of the cassette insertion / ejection unit 2b to propagate to the sub-scanning unit 50 is realized.

An anti-vibration rubber 74 is disposed between the upper end of the sub-scanning section 50 and an apparatus frame (not shown) to reinforce the anti-vibration structure for the sub-scanning section 50.

With such a vibration-proof structure, a cassette is inserted into the insertion slot 3 or a cassette is taken out from the discharge port 4 while image information is being read from the stimulable phosphor sheet 28 in the main body 2a. Also, even if the apparatus main body 2 is vibrated, it is possible to prevent generation of noise due to vibration in the read image information.

Further, since the sub-scanning section 50 and the transport means 40 are constructed on the same substrate 71, as will be described later, when the back plate 20 is transferred from the transport means 40 to the sub-scanning section 50, the transfer position There is no blurring. This allows
Separation and uniting work of the front plate 10 and the back plate 20 can be stably and accurately performed.

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

As shown in FIG. 3, the cassette 1 on which the radiographic image has been taken is inserted into the insertion slot 3 in the direction of arrow A1. At this time, the insertion is performed so that the insertion hole 14 faces downward 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 thereof faces obliquely downward. When the cassette 1 is inserted into the insertion slot 3, the presence of the cassette 1 is recognized by a cassette detection sensor (not shown), and the cassette is moved to the center of the insertion slot 3 by the width adjusting means 47 arranged in the insertion slot 3. It is narrowed down to.

When the cassette is moved toward the center of the insertion slot 3, the code attached to the back plate back surface 210 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 transport means 40 is started in accordance with the cassette size. That is, the width shifting means 401a of FIG.
401b starts moving in the direction of arrow M according to 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 arrow A2. By the time the insertion roller 42 operates, the transport means 40 is already waiting at the position indicated by the dotted line a, and receives the cassette 1 carried by the insertion roller 42 from the insertion port 3. When the cassette grips 402a and 402b on the lift platform 402 (operating along the transport unit 40) catch the lower end of the cassette 1, the lift platform 402 transports the cassette 1 along the transport unit 40 in the direction of arrow A2. The upper end of the cassette 1 is controlled so as to stop at the position indicated by the arrow Z in FIGS.

FIG. 5 is a diagram showing how different cassette sizes have a positional relationship on the transport mechanism 40. 1A is a half-sized cassette, 1B is a large-sized cassette, 1C is a large-sized cassette, 1D is a 4-sized cassette, 1E is a 6-sized cassette, 1
Fa is 24x30cm size cassette, 1Fb is 24
A cassette for mammography with a size of 30 cm, 1 Ga
18x24cm size cassette, 1Gb is 18x2
4cm size mammography cassette, 1H is 15x3
This is a 0 cm size dental cassette. Regardless of the size of all cassettes, the position of the elevator 402 is controlled so that the upper end of the cassette is located at the position indicated by the arrow Z. In this manner, a method of controlling the upper end of the cassette 1 to always stop at the same position of the transport means 40 is referred to as upper reference control.

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

1) Since the time required for the sub-scanning section 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) The tip (upper end) of the cassette can be made to protrude by the same distance from the sub-scanning moving plate 53 irrespective of the cassette size (see FIGS. 4 and 5). Edge detection (see FIG. 7) can be performed. Thereby, the reading area of the stimulable phosphor sheet 28 can be accurately determined. Further, it is possible to construct a rough and inexpensive mechanism by lowering the transport accuracy of the cassette 1 in the transport unit 40 and the delivery accuracy of the back plate 20 from the transport unit 40 to the sub-scanning unit 50.

Of course, a lower reference control, that is, a method of controlling the position of the cassette lift 402 so that the lower end of the cassette 1 always stops at the same position of the transport means 40 may be adopted. In this case, The two advantages described above cannot be obtained.

The dotted line V in FIG.
Center line. The width adjusting means 40 is adjusted so that the center of all cassettes is aligned with the center line of the sub-scanning moving plate 53.
1a and 401b are controlled. This is called center-based control.

In general, when a film or a stimulable phosphor sheet is conveyed, a one-side reference control for conveying the film or the stimulable phosphor sheet to one side is performed.
In the case of this embodiment, since the transporting means 40 and the sub-scanning unit 50 must handle cassettes 1 and back plates 20 of various sizes, in the control on one side reference, the center of gravity of the cassette 1 and the back plate 20 in the horizontal direction is controlled. The position does not match the center of the sub-scanning moving plate 53 or the elevating table 402, and the balance of sub-scanning and conveyance is lost. Further, the cassette 1 and the back plate 20
Is an object that is considerably heavier than a film or a stimulable phosphor sheet, so that the imbalance in control on one side is not preferable in terms of reliability and stability. Therefore, in this embodiment, control based on the center is preferable.

When transferring the back plate 20 between the transport mechanism 40 and the sub-scanning mechanism 50, the cassette grip 40
2a, 402b and the sub-scanning moving plate 53 (or the rubber magnet 54) interfere with each other.
b is provided. In one-sided control, the position of the interference avoiding aperture cannot be specified, and a more complicated mechanism is required.
In this sense, the center-based control is preferable in this embodiment.

In this embodiment, the control based on the center reference is adopted. However, the control of the one-side reference avoiding the above problem does not impair the essence of the present invention.

When the cassette 1 is stopped in accordance with the control based on the upper side, the tips of the grip claws 403a and 403b are brought into contact with the grip recesses 16a on the side surface 110 of the front plate.
The front plate 10 is inserted into the recess 16b and fixed to the conveying means 40.

The transporting means 40 has a rotating shaft 404, and can freely rotate and move around the rotating shaft 404 at least in the range from the dotted line a to the dotted line c (the range of the angle θ). When the cassette 1 is taken into the apparatus main body 2 by the transport mechanism 40, the transport mechanism 40 rotates around the rotation shaft 404 from the position indicated by the dotted line a to the position indicated by the dotted line C in the direction of the arrow A3. When the transport mechanism 40 is rotated to the position indicated by the dotted line c, the back plate back surface 210 of the cassette 1 having the ferromagnetic material is
Is attracted by magnetic force.

FIG. 4 shows the back plate back surface 210 of the cassette 1.
Shows a state where the rubber magnet 54 is magnetically attracted to the rubber magnet 54. In the present embodiment, it is a diagram assuming a cassette of six-section size. The width shifting means 401a and 401b adjust the cassette 1 of the six-cut size to the center reference. The width shifting means 401a, 401b, the lock pin 402c, and the elevating table 402 do not project toward the sub-scanning moving plate 53 from the back plate back surface 210 of the cassette 1 so as not to interfere with the sub-scanning moving plate 53. Designed for In order to avoid interference between the cassette grips 402a and 402b and the sub-scanning moving plate 53 (or the rubber magnet 54), the sub-scanning moving plate 53 is provided with an interference avoiding opening 54.
0a and 540b are provided.

A lock pin 402c for turning on / off the lock mechanism of the cassette 1 is disposed on the lift table 402, and the lock mechanism of the cassette 1 is turned on / off by moving the lock pin 402c up and down. be able to. The upper end of the cassette 1 (upper reference position Z)
Is configured so that the upper end of the cassette 1 protrudes above the sub-scanning moving plate 53 of the sub-scanning unit 50 in order to detect the upper end or the side end of the cassette 1 during sub-scanning.

The sub-scanning section 50 includes a sub-scanning rail 51, sub-scanning movable sections 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 the driving portion (not shown) moves the sub-scanning moving plate 53 to the sub-scanning rail 51.
It is configured to be able to move up and down. As the sub-scanning rail 51, a linear guide, a linear bearing guide, or the like having high transport performance can be used.

In this embodiment, the rubber magnet 54
Is a permanent magnet having a predetermined area. The rubber magnet is provided with interference avoiding openings 540a and 540b as shown in FIG.
May be attached to the entire surface of the sub-scanning moving plate 53, or a predetermined number of rubber magnets may be divided and attached to the sub-scanning moving plate 53. Further, the rubber magnet can take any shape. Also,
Permanent magnets and electromagnets other than rubber magnets can be used.

Back plate back surface 21 of rubber magnet 54
The surface portion that adsorbs 0 has high flatness, and when the rubber magnet 54 adsorbs the back plate back surface 210, the ferromagnetic surface of the back plate back surface 210 follows the plane of the rubber magnet 54, and thus the stimulable phosphor It is considered that the reading surface of the sheet 28 is as perfect as possible. Therefore, even if the back plate 20 is deformed or warped,
When the back plate back surface 210 is attracted to the rubber magnet 54, its deformation and warpage are corrected, and the reading surface of the stimulable phosphor sheet 28 can maintain flatness.

When the back plate 20 is attracted to the rubber magnet 54, the lock pin 402c housed in the lift table 402 rises, and the tip of the lock pin 402c is inserted into the insertion hole 14 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 cassette 1 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 descends and is stored in the elevator 402 again.

The lock of the cassette 1 is released and the lock O
When the state shifts to the FF state, the transport mechanism 40 rotates and moves in the direction of arrow A6 and stops at the retracted position (for example, the position indicated by the dotted line b). By this operation, the back plate 20 and the front plate 10
Is 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 transport mechanism 40 is stopped at the retracted position. The cassette 1 is assumed to be a half-sized cassette. By retracting the front plate 10 at a sufficient angle from the back plate, it is possible to prevent the back plate 20 from interfering with the front plate 10 when the back plate 20 performs the sub-scanning operation. As described above, means for performing a series of operations for separating the back plate 20 and the front plate 10 is generally 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) operates, and the back plate 20 is transported (sub-scanned) in the direction of arrow A4 (upward). . During this sub-scanning operation, the stimulable phosphor sheet 28 is main-scanned by the laser light B emitted from the laser scanning unit 61 in a direction perpendicular to the sub-scanning direction.

When laser light acts on the stimulable phosphor sheet 28, stimulable light (image information) proportional to the radiation energy stored in the stimulable phosphor sheet 28 is emitted,
The stimulated emission passes through the light guide 62 and is collected in the condenser tube 63. The condenser tube 63 is, for example, disclosed in Japanese Patent Application No. 2000-10390.
It is preferable to use a light collecting tube having a structure as described in Japanese Patent Application Laid-Open Publication No. HEI 7-303, 1988. On the end face of the condenser tube, a photoelectric conversion element such as a photomultiplier (not shown) is arranged.
The collected photostimulated light is converted into an electric signal. After being subjected to predetermined signal processing as image data, the photostimulated light converted into an electric signal is transmitted from the device main body 2 via a communication cable (not shown) to an operation terminal, an image storage device, an image display device, a dry imager. To an image output device (neither is shown).

As described above, the laser scanning unit 61,
A unit configured to read image information, which includes the light guide 62, the condenser tube 63, the photoelectric conversion element, and the like, is defined as a reading unit 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 stimulable phosphor sheet 28.

It is preferable that the start time of image data capture 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 continuously receives the laser beam B and continuously outputs a signal having a predetermined intensity. However, when the upper end of the back plate 20 moves to a position where the laser beam B is blocked, the sensor 90 Since the signal strength of the electric signal output from the power supply decreases, the upper end of the back plate 20 can be detected. Alternatively, a mechanism as shown in FIG. 7 may be used to detect the side edge of the back plate 20. FIG. 7 (A1) is a diagram showing a state where the back plate 20 has not reached the scanning position of the laser beam B. A rod 91 is connected to the light receiving surface of the sensor 90, and the laser beam B reaches the sensor 90 along the rod 91. The laser light reaching the sensor 90 is photoelectrically converted by the sensor 90 and output as an electric signal.

The rod 91 is, for example, a hollow tubular member having an opening for introducing the laser light B, and at least a substance that diffuses light is present at least on the inner wall portion of the tube where the laser light B directly acts. It has been applied. In addition, rod 9
Reference numeral 1 denotes, for example, a rod-shaped plastic member or a glass member, and a material that reflects or diffuses light is applied to an outer wall other than the opening for introducing the laser beam B.

FIG. 7 (B1) is a diagram showing the signal strength of the electric signal output from the sensor 90 in the state shown in FIG. 7 (A1). The signal strength rises at time T0, and gradually decreases with the passage of time.
2, which disappears at the time when the laser beam B passes through the right end of the rod 91.

FIG. 7A2 is a view at the moment when the upper end of the back plate 20 reaches the scanning position of the laser beam B. The signal strength of the electric signal output from the sensor 90 at this time is shown in FIG. 7 (B2). The signal strength rises at time T0, but sharply decreases at time T1, ie, the time when the laser beam B passes through the left end of the cassette 1. Therefore, if the time T1 is detected by signal processing or the like, the side end (the left end in the present embodiment) of the cassette 1 can be detected, and
As a result, it becomes possible to control the Hsync of the laser light and calculate the generation timing of the image data.

As described above, if the upper end and the side end of the back plate 20 can be detected, the reading area of the stimulable phosphor sheet 28 can be determined with high accuracy. In addition, such a back plate 20
By using the edge detection means, the accuracy of transporting the cassette 1 by the transport means 40 and the accuracy of transferring the back plate 20 from the transport means 40 to the sub-scanning unit 50 are reduced, and a rough and inexpensive mechanism is constructed. Becomes possible.

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

When reading of the image information from the stimulable phosphor sheet 28 is completed, the driving unit (not shown)
Is started in the direction of arrow A5 (downward). While the back plate 20 is being conveyed in the direction of the arrow A5, the erasing light C is emitted from the erasing means 64, and the stimulable phosphor sheet 28 is emitted.
The remaining image information is erased. The erasing lamp used in the erasing means 64 includes a halogen lamp, a high-intensity fluorescent lamp,
An LED array or the like can be used.

As described above, in this embodiment, image information is read on the outward path (upward transport) of the sub-scanning section 50, and remains on the return path (downward transport) of the sub-scanning section 50. Since the image information is erased, the time required for the reciprocating movement of the sub-scanning unit 50 can be effectively used without wasting. Thereby, the processing capability (throughput) of the radiation image reading apparatus can be improved.

In this embodiment, the erasing means 64
Are arranged at the lower part in the vertical direction of the reading means 60, so that when the reading operation of the image information by the reading means 60 is completed, the moving direction of the sub-scanning section 50 can be immediately switched to the backward direction (downward). Thereby, the sub-scanning unit 50
Since the erasing operation can be started without a loss of time during the reciprocating motion, the processing capability (throughput) of the radiation image reading apparatus can be further improved.

Further, since the erasing means 64 is disposed below the reading means 60 in the vertical direction, the lower end of the back plate 20 does not pass through the reading position B of the reading means 60. It is possible to prevent an accident that the back plate cannot be lowered due to interference with the light collecting member such as 62. Because of this, the reliability of the device. Stability can be improved.

When the back plate 20 is lowered to the position transferred to the rubber magnet 54, the driving 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 transferred to the rubber magnet 54, the transporting means 40 retracted to the retracted position is rotated again to the position indicated by the dotted line c,
The back plate 20 and the front plate 10 are combined. When the back plate 20 and the front plate 10 are united, the lock pins 402c housed in the elevating table 402 rise, and the tips of the lock pins 402c are inserted into the insertion holes 14 of the front plate 10. By this operation, the cassette 1 which has been in the lock OFF state is locked, and the cassette 1 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 descends, and the elevator 40
2 is stored. 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 is collectively referred to as uniting means.

When the joining operation of the back plate 20 and the front plate 10 is completed by the joining means, the conveying means 40 is again rotated in the direction of arrow A6 to the position of the dotted line b and stopped.
Thus, the back plate 20 is removed from the rubber magnet 54.
Since the operation of peeling off the (cassette 1) is performed along with the rotational movement, the back plate 20 (cassette 1) can be peeled off from the rubber magnet 54 with a smaller force as compared with the case of peeling off by the parallel movement. is there.

When the conveying means 40 stops at the position indicated by the dotted line b, the front plate 1 is gripped by the grip claws 403a and 403b.
The fixed state of “0” is released, and the cassette 1 becomes a state in which the cassette 1 can be transported on the transport unit 40.

When the fixed state of the front plate 10 is released, the elevator 402 conveys the cassette 1 in the direction of the discharge port 4 along the conveying means 40, and moves the cassette 1 to the discharge roller 4
Hand over to 3. Upon receiving 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 mechanism 40 rotates to the position indicated by the dotted line a in the direction of arrow A6, stops, and shifts to a state in which the next cassette 1 can be received.

In this embodiment, a stacker unit capable of stacking about 2 to 5 cassettes 1 at the discharge port 4 is provided. When the position of the cassette 1 immediately after the discharge to the discharge port 4 is completed is represented by 1a, the cassette 1 discharged to the place of 1a falls down in the direction of arrow A8 from the upper end of the cassette 1 due to the weight of the cassette 1, and the final position. To the position represented by 1b. The bottom plate portion of the discharge port 4 is inclined from the side 1a toward the side 1b so that this operation is performed only by the weight of the cassette 1. Further, in order to reliably transport the cassette 1 from the side 1a to the side 1b, for example, a transport mechanism 44 for transporting the lower portion of the cassette 1 in the direction of arrow A8 is provided, and the entire cassette 1 is moved 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 does not need to remove the discharge cassette 1 until the discharge port 4 is filled with the discharge cassette 1. The photographed cassette 1 can be sequentially inserted into the insertion opening 3. In general, a radiographic examination uses 1 to 5 cassettes in one examination, and about 1.8 sheets on average. Therefore, the discharge port 4 is configured so that about 2 to 5 discharge cassettes 1 can be stacked. By doing so, the user is less bothered to remove the discharge cassette 1 during the inspection, and the work can be performed efficiently.

The transport means 40 in this embodiment is configured to separate the front plate 10 and the back plate 20 after the back plate 210 of the back plate 20 is attracted to the rubber magnet 54, but the front plate 10 is separated. After separating the back plate 20 and the back plate 20, the back plate back surface 210 of the back plate 20 may be attracted to the rubber magnet 54.

Although the front plate 10 and the back plate 20 are separated after the cassette 1 is rotated, only the back plate 20 is rotated after the front plate 10 and the back plate 20 are separated. May be configured.
Further, the back plate 20 and the plate 29 are transferred to the sub-scanning unit 50 by rotating the transport unit 40. However, when the sub-scanning moving plate 53 is partially or entirely rotated, the back plate 20 or the plate 29 is rotated. Plate 20 or plate 2
9 may be passed to the sub-scanning unit 50.

Next, the sub-scanning section 50 of this embodiment will be described with reference to FIG. FIG. 2 is a partially transparent perspective view showing a transport mechanism in the sub-scanning unit 50 in the main reading unit 3. In FIG. 2, the back plate 20 shown in the figure has a ferromagnetic portion made of iron or the like on a part on the mounting surface side, and a rubber magnet 5 on the mounting surface of the support.
4 or a permanent magnet is magnetically attracted to a sub-scanning moving plate 53 to which a double-sided tape or an adhesive is attached.

On the back side of the support of the sub-scanning moving plate 53, a linear sub-scanning rail 51 fixed vertically to a frame (not shown) is engaged and guided. The pulley 451 is connected via a direct drive and a coupling 452 to a motor 453 fixed to a frame (not shown). Further, when there is a restriction on the number of rotations of the motor, the motor 45
A speed reduction mechanism 450 including a motor pulley 454 and an endless belt 458 may be provided between the pulley 3 and the pulley 451. This drawing shows a case where the speed reduction mechanism is used. In the speed reduction mechanism of the present embodiment, the motor pulley 402 and the motor pulley 454 are preferably made of stainless steel, and the endless belt 458 is preferably made of a material having a Young's modulus of 1.5 kgf / mm ² or more. 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 via a driven pulley 470 rotatably attached to a frame (not shown). 460
Is connected to the upper end of When there are a plurality of types of back plates 20, the mass of the counterweight is substantially equal to the total mass of the lightest plate and the sub-scanning moving plate 53. Also, if the sub-scanning moving plate 53 moves upward,
The counterweight 460 is formed so that its moving direction is directly opposite, such as moving downward.

As shown in FIG. 8, a roller 501 and a tension spring 502 are arranged between the driven pulley 470 and the counterweight 406 so as to press the belt 440 in a direction substantially perpendicular to the traveling direction. Extension spring 502
Is suspended between a shaft 503 and a shaft 504 so that the roller 501 is constantly pressed against the belt 405. The tension of the tension spring 502 is equal to that of the belt 405.
Is appropriately selected in accordance with the tension of. Adjustment of the pulling force may use a spring constant that has been changed.
The mounting position of the shaft 504 may be changed. Also, the pressing direction of the belt 405 is changed in the direction opposite to the direction of the figure.
5 may be arranged in such a manner as to be pressed. Also,
In the figure, a configuration using a tension spring is described, but a pressing spring that presses the roller 501 may be used.

The roller 501 and the tension spring 502 may be arranged closer to the sub-scanning moving plate 53 than the suction plate 404, and the driving pulley 459 and the driven pulley 47 are provided.
0 may be arranged. Moreover, you may arrange by these multiple combination. Counterweight 460 and belt 4
The connecting portion 40 has a rotation mechanism that can freely rotate in a direction substantially perpendicular to the traveling direction. Therefore, belt 4
Even if 40 reciprocating bending movements occur, there is no break. In addition, since the belt 405 is rotatable about an axis substantially perpendicular to the traveling direction, even if the relative positional relationship between the linear guide 410 and the belt 405 is not parallel to the traveling direction, the belt 405 does not twist. Also, no image unevenness occurs due to the restoration impact of the belt 405 during the reading operation. In addition, a similar effect can be obtained at the connecting portion between the suction plate 404 and the belt 405, so that the effect is further enhanced.

Next, the operation of the book reader according to the present embodiment will be described. The laser beam is deflected and emitted from the laser scanning unit 61 and is emitted to irradiate the stimulable phosphor plate 28 provided on the back plate 20. At this time,
Since a luminous phenomenon occurs from the stimulable phosphor layer on the surface of the stimulable phosphor plate 28 in accordance with the latent image, the light emission
The light is condensed, photoelectrically converted, signal processed, and the image is read.

On the other hand, the motor 453 rotates the pulley 451 at a constant speed, but the driving force from the motor is driven by the frictional force via the coupling 452 and the speed reduction mechanism 450 using the endless belt 458 and the motor pulley 454. Is transmitted. The endless belt 458 is maintained at a predetermined tension by a tension adjusting mechanism (not shown) not only for transmitting the power of the speed reduction mechanism but also for ensuring precise constant speed control and positioning accuracy. If there is no restriction on the motor rotation speed, the output shaft of the motor 453 may be arranged coaxially with the rotation shaft of the pulley 451 and directly connected using a coupling or the like.

The pulley 451 rotating at a constant speed
Is driven by the frictional force of the belt 440 in contact therewith, whereby the back plate 2 and the sub-scanning moving plate 53 guided by the sub-scanning rail 51 precisely in the vertical direction.
0 moves upward, and the entire surface of the back plate 20 can be scanned. When erasing the latent image, if the erasing means is located below the main scanning portion, the motor 453 is rotated in the direction opposite to the reading direction, and the sub-scanning moving plate 53 is moved downward.

When the erasing means is located above the main scanning portion, the image may be erased immediately after reading the image. The stimulable phosphor plate may be moved downward during reading and moved upward during erasing. May be.

When the belt 440 is driven, a drive pulley 459 and a backup roller 451 having no drive paired with the drive pulley 459 may be provided, so that the belt 440 is pressed and clamped. As a result, the frictional force between the pulley and the belt can be increased, so that the use of a backup roller can further improve the transfer accuracy.

The belt to be used has a Young's modulus of 1.5 k.
gf / mm ² or more is preferable, using a metal belt, a metal wire, a resin belt, etc.
One or a plurality of combinations may be applied in parallel. One or more belts may be arranged on the center line in the sub-scanning direction, or a plurality of belts may be arranged at line-symmetric positions with respect to the center line.

The linear motion guide is located on the center line in the sub-scanning direction.
A plurality of linear guides may be arranged at a line symmetrical position with respect to the book or the center line. However, when assembling is taken into consideration, a smaller number of linear motion guides is preferable because the time required for parallelism adjustment can be reduced. Further, when only one linear motion guide is arranged, it is more preferable because the parallelism adjustment between a plurality of linear motion guides is substantially unnecessary.

[0095] The used quantity of each of the belt and the linear motion guide can be freely selected as required. Also, the vibration damping means can be selected as necessary, similarly to the number of belts used.

In the radiation image reading apparatus of the present embodiment, a rotating body as a friction driving body, that is, a pulley 451 drives a belt 440 as a friction driven section connected to the sub-scanning moving plate 53. Therefore, there is no need for a drive unit such as a conventional ball screw. Therefore, not only the assembling becomes easy, but also the device configuration can be made simple, compact and inexpensive.

Further, by configuring the speed reduction mechanism 450 in the process of transmitting the drive from the motor 453 to the pulley 451, the degree of freedom of the arrangement position of the motor 453 in the apparatus is remarkably increased. On the upper side, the distance between the sub-scanning moving plate 53 and the counterweight 460 can be arranged as close as possible to the diameter of the pulley 451 without restricting the above operation, so that the apparatus configuration is made more compact. Contribute to. In the speed reduction mechanism, the motor pulley 402 and the motor pulley 454 are made of stainless steel because the processing accuracy and rust prevention can be easily managed. However, in order to reduce the cost of the device, a resin material may be used.
In order to increase the frictional force with the endless belt 458, a coating such as tungsten spraying may be performed. The holding of the back plate 20 is performed because the ferromagnetic material such as iron formed on at least a part of the back plate 20 is held by the rubber magnet 54 attached to at least a part of the sub-scanning moving plate 53, A complicated mechanism for holding is not required in the device, which contributes to downsizing of the device.

When the back plate 20 is held, the holding and non-holding states of the back plate 20 may be arbitrarily switched by using an electromagnet, and a permanent magnet is used to reduce the cost of the apparatus. May be. Further, even when the back plate 20 is slightly deformed due to the handling of the user or the like, the surface of the sub-scanning moving plate 53 is maintained in a plane with a predetermined accuracy, and the reading is performed by the back plate 20 being flat with this plane. In order to maintain the planar accuracy of the image surface during scanning, it is possible to easily control the accuracy of the back plate 20 and the cassette for housing the same.

Further, the back plate 20 and the sub-scanning moving plate 53
Weight 460 with a total mass of approximately equal
Is connected to the sub-scanning moving plate 53 via the belt 440,
It is fixed and guided by a linear motion guide 410 fixed to a frame (not shown). Furthermore, since the sub-scanning moving plate 53 is driven in a 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 can be canceled. The driving reaction force during the movement of 53 can be reduced.

In particular, in the present embodiment, since the moving direction of the sub-scanning moving plate 53 is the anti-gravity direction,
In moving the motor 453 in the lifting direction, the load at the time of starting the motor 453 can be reduced.

Next, the effect of the counterweight 460 will be described. When there are a plurality of types of back plates 20, when the weight of the counterweight 460 is made equal to the total weight of the lightest back plate 20 and the sub-scanning moving plate 53, the sub-scanning moving plate 53 is moved together with the back plate 20. When the motor 453 is lifted, the load applied when the motor 453 is started is obviously reduced as compared with the case where no counterweight is configured, so that the motor used can be reduced in size.

During the reading operation requiring the highest 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. More desirably, the total mass of the back plate 20 and the sub-scanning moving plate 53 may be different from the mass of the counterweight 460 in some cases. In this case, one of the suction plate portion and the counterweight is urged in the direction of gravity, and as a result, the motor 453 is constantly rotated with respect to the motor 453 during the constant-speed rotation except when the motor 453 is started or stopped. A constant load is applied, thereby enabling precise constant speed control and accurate positioning.

When the total weight of the back plate 20 and the sub-scanning moving plate 53 is balanced, and the weight of the weight 460 is light,
This is effective when the stimulable fluorescent plate is moved upward during reading. On the contrary, when the total weight of the back plate 20 and the sub-scanning moving plate 53 is balanced and the weight 460 is heavy, the stimulable fluorescent plate is moved. This is effective when the fluorescent plate is configured to be moved downward during reading.

Therefore, the back plate 20 and the sub-scanning moving plate 53
The difference between the total mass of the motor and the mass of the counterweight 460 is small. By making the difference small, the effect of both the miniaturization of the motor and the precise constant velocity control and accurate positioning can be obtained. In the case where there are a plurality of types of back plates 20, the weight of the counterweight 460 is reduced with respect to the total weight of the lightest back plate 20 and the sub-scanning moving plate 53, or the weight is reduced. It is more preferable that the counterweight 460 be heavier than the total weight of the back plate 20 and the sub-scanning moving plate 53.

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

Further, a sub-scanning rail 51 for guiding the sub-scanning moving plate 53 is provided, and when viewed from the direction of the image forming surface of the back plate 20, the center line of the sub-scanning rail 51 in the vertical movement direction is: The center of gravity of the combination of the back plate 20 and the sub-scanning moving plate 53 (that is, in the present embodiment, since the sub-scanning moving plate 53 is bilaterally symmetric,
3 (on the vertical center line in the vertical direction) because the sub-scanning moving plate 53 and the back plate 20 can be guided with a good weight balance. In addition, when assembling is taken into consideration, it is needless to say that when only one belt is used, the assembling time is shorter than when a plurality of belts are configured in parallel, and the parts between the plurality of belts are used. It is substantially unnecessary to consider adverse effects that may occur due to errors in accuracy or assembly. This is more preferable because the requirements for component accuracy and assembly accuracy can be relaxed.

Similarly, when assembling the linear guides in consideration of the assembling time, it is preferable that the number of the linear guides is small because the time required for adjusting the parallelism can be reduced. Further, it is more preferable that only one linear guide is used, because it is not necessary to substantially perform the parallelism adjustment that occurs when a plurality of linear guides are arranged in parallel.

At both ends of the belt 440, the sub-scanning moving plate 5
3 and a counterweight of approximately the same weight as the suction plate 4
60 are fixed, and the belt 440 can be maintained at an appropriate tension by using the mass thereof, whereby the frictional force between the pulley and the belt increases,
Precise constant speed control and accurate positioning are possible. It is preferable to use a steel belt made of stainless steel, which has extremely low elasticity among the materials of the belt, as the belt 440 can improve the transport accuracy. However, depending on the apparatus configuration, a metal wire may be used. Or a resin belt or the like, or a combination thereof.

Further, by providing the backup roller 451, the frictional force between the pulley and the belt can be increased, so that the drive transmission performance of the belt can be maintained higher and the frictional force between the pulley and the belt can be increased. This makes it possible to reduce the weight of the counterweight 460 with the sub-scanning moving plate 53, thereby contributing to the weight reduction of the entire apparatus.

Further, the counterweight 460 and the belt 440
Since the connecting portion 464 is provided so as to freely rotate in a direction substantially perpendicular to the traveling direction, the belt 405
It does not break even if the reciprocating bending motion of.

Also, since the belt can be rotated about an axis substantially perpendicular to the traveling direction, the belt 405 may be twisted even if the relative positional relationship between the linear guide 410 and the belt 405 is not parallel to the traveling direction. No image unevenness occurs due to the impact of the restoration of the belt 405 during the reading operation.
Therefore, by these effects, it is possible to prevent the feed speed unevenness of the suction plate 404 from being deteriorated, and it is possible to obtain a good diagnostic image without image unevenness.

By transmitting the drive between the motor 453 and the pulley 451 by using the reduction mechanism 450 using the motor pulley 454 and the endless belt 458, the reduction ratio can be set to an arbitrary state. It is possible to easily design the frequency band so as not to affect the natural frequency of the device, thereby achieving precise constant speed control and improving the accuracy of positioning, thereby contributing to the improvement of the quality of diagnostic images. In addition, the endless belt 458 in the present embodiment.
As for, a nickel electroformed belt is used in view of easiness of component production and stability of component accuracy, but a belt made of other metal such as stainless steel or resin may be used.

Although the present invention has been described with reference to the embodiments, it should be understood that the present invention should not be construed as being limited to the above-described embodiments, and that modifications and improvements can be made as appropriate. is there. For example, a toothed belt may be used as the belt, and the belt may be engaged with a belt on which a pulley is hung.

If the sub-scanning moving plate 53 of the sub-scanning section 50 is configured to be able to be moved up and down manually, the sub-scanning moving plate 53 can be manually operated to a position where the back plate 20 can be easily peeled off from the rubber magnet 54. it can.

In the radiation image reading apparatus of the present embodiment, the counterweight 40 and the suction plate 404 are used.
6 vibrates in the traveling direction via the belt 405, so that the feeding speed unevenness of the suction plate is deteriorated, and as a result, image unevenness may occur, which may hinder the diagnostic image. By pressing the roller 501 between the suction plate 404 and the counterweight 406 so as to press the belt 405 in a direction substantially perpendicular to the traveling direction, the vibration of the belt 405 can be absorbed. Vibration amplification can be prevented.

The rotation shaft 505 of the roller 501 is rotatably held on both sides by side plates 506 on both sides. The side plates 506 on both sides are supported by a fulcrum shaft 503 provided at a position away from the rotation shaft 505 of the roller 501.
And a shaft 5 provided at a position distant from the fulcrum shaft 503.
07. And this fulcrum shaft 503
Is rotatably held by a frame (not shown).
And these are fulcrum shafts 50 as an integrated unit.
3 so as to be rotatable.

A shaft 504 fixed to a frame (not shown) is separated from the rotation range of the unit.
Is provided. Further, a tension spring 502 is bridged between the shaft 507 and the shaft 504, and constantly urges the roller 501 to be pushed into the belt 405.
Accordingly, the vibration of the belt 405 can be absorbed, and the amplification of the vibration of the suction plate 404 can be prevented.

Note that the image forming apparatus of the present invention is applicable not only to the medical field but also to general image reading apparatuses.

[0119]

According to the present invention, the amplification of the vibration amplitude in the sub-scanning mechanism can be suppressed, so that a good image in which image unevenness is suppressed in the image read while performing sub-scanning by the sub-scanning mechanism can be obtained. Obtainable. In particular, even if the present invention is applied to a medical diagnostic image requiring high image quality, a good image suitable for the medical diagnostic image can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view when a front plate and a back plate of a cassette are separated.

FIG. 2 is a partially transparent perspective view showing a transport mechanism in a sub-scanning unit 50.

FIG. 3 is a diagram illustrating a configuration example of a radiation image reading apparatus.

FIG. 4 is a diagram illustrating a relationship between a conveying unit and a sub-scanning unit when transferring a back plate.

FIG. 5 is a diagram illustrating a positional relationship of a cassette based on an upper reference and a center reference;

FIG. 6 is a diagram illustrating a relationship between a conveying unit and a sub-scanning unit in a retracted state.

FIG. 7 is a diagram illustrating a side edge detection method of the back plate.

FIG. 8 is a detailed view of a vibration damping means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1K cassette 2 Main body 2a Main body part 2b Cassette insertion / ejection part 3 Insertion opening 3a, 3b Insertion / extraction opening 3c, 3d Loading opening 4 Emission opening 5 Opening door 10 Front plate 20 Back plate 28 Stimulable phosphor sheet 29 Plate Reference Signs List 40 conveying means 50 sub-scanning section 54 magnet 60 reading means 64 erasing means 70 bottom plate 80 display means

Claims (8)

[Claims] 1. A plate-like member to which the stimulable phosphor sheet is attached, or holding means for holding the stimulable phosphor sheet, a guide means for guiding the holding means, and for moving the holding means. A driving unit for driving, a transmission unit for moving the holding unit, a drive transmission unit for transmitting the drive of the driving unit to the transmission unit, and a counterweight coupled to the holding unit via the transmission unit, Main scanning means for scanning in a direction orthogonal to the direction of movement of the holding means, and when the driving means is driven, the storage means moves in the direction opposite to the moving direction of the counterweight, and An image reading unit configured so that a body sheet is main-scanned by the main scanning unit, and a vibration damping unit is arranged between the holding unit and the counterweight; apparatus. 2. An image scanning apparatus according to claim 1, wherein said vibration damping means includes a roller and a spring. 3. The image scanning device according to claim 1, wherein a rotation mechanism for rotating said transmission means is provided at a joint between said counterweight and said transmission means in a direction substantially perpendicular to a traveling direction. apparatus. 4. The image scanning apparatus according to claim 1, wherein a rotation mechanism for rotating said transmission means is provided at a connecting portion between said holding means and said transmission means in a direction substantially perpendicular to a traveling direction. apparatus. 5. The image scanning device according to claim 1, wherein the connecting portion between the holding unit and the transmitting unit is rotatable about an axis substantially perpendicular to a traveling direction. 6. The transmission means connected to the drive means, and a backup roller for improving a frictional force on a side of the transmission means opposite to the drive transmission means when the transmission means is driven by friction. The image reading device according to claim 1. 7. The transmission means has a Young's modulus of 1.5 kgf / mm ^2.
The image reading device according to claim 1, wherein the image reading device is formed of the above material. 8. An image reading apparatus according to claim 1, wherein said transmission means is a metal belt.