JP2006113169A - Image scanner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image scanner for obtaining excellent diagnosing images without image irregularity. <P>SOLUTION: The image scanner for reading image information by irradiating a stimulable phosphor plate P with exciting light L1 comprises an optical unit 1 irradiating and scanning the stimulable phosphor plate P with the exciting light L1 from a light source and reading the image information by condensing and photoelectric-converting stimulable luminescense light emitted from the stimulable phosphor plate P; a support member 2 mounted through a vibration-proof member 4 on a body frame 8 and movably supporting the optical unit 1 in a horizontal direction; a linear motor for moving the optical unit 1; and a first guide rail 31 provided on the support member 2 and guiding the optical unit 1 in the horizontal direction. In addition, the support member 2 is balanced with the optical unit 1, and provided with a balancer 5 moved relatively by being interlocked with movement of the optical unit 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus, and more particularly to an image reading apparatus excellent in scanning transportability of a photostimulable phosphor plate suitable for use in the medical field or printing field.

Radiation images such as X-ray images are often used for disease diagnosis and the like. Conventionally, in order to obtain such a radiographic image, X-rays that have passed through a subject are irradiated onto a phosphor layer (fluorescent screen), thereby generating visible light and taking a normal picture 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 absorption by exciting the phosphor with, for example, light or thermal energy. Some radiation energy is emitted as fluorescence, and this fluorescence is detected and imaged. A stimulable phosphor plate in which a stimulable phosphor layer is formed on a support is used. The stimulable phosphor layer of this stimulable phosphor plate is irradiated with radiation transmitted through the subject, Radiation energy corresponding to the radiation transmittance of each part is accumulated to form a latent image, and then the stimulable phosphor layer is scanned with stimulated 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 via a photoelectric conversion means such as 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 the image storage device as necessary, via a silver salt film, a CRT, or the like. Can be visualized.

By the way, when the photostimulable phosphor plate is scanned with the photostimulable excitation light, the image reading unit (optical unit) must be precisely moved relative to the photostimulable phosphor plate at a constant speed. That is, constant speed is required in a conveyance body such as an image reading unit, and high-performance speed control is required.
However, the image reading unit is provided, for example, with a base in the apparatus main body, and is provided in a box placed on the base. For this reason, external vibration applied to the apparatus main body may be transmitted to the image reading unit through the base and the box, which may affect the movement of the image reading unit. For this reason, a technique is known in which the box body in which the image reading unit is arranged is fixed on a base via vibration isolation means such as vibration isolation rubber (for example, see Patent Document 1).
JP 11-305362 A

However, as described above, when the image reading unit is moved from the image reading start end to the terminal end of the stimulable phosphor plate in the box, the vibration-proof rubber or the like is bent due to the weight of the image reading unit. In some cases, the image reading unit is conveyed in an inclined state. As a result, rising and falling slopes occur in a series of operations with the transport center as the boundary, speed fluctuation occurs when transported by a linear motor, and the stimulable phosphor plate is excited by stimulating light. When scanning with, the image becomes uneven and there is a problem that the diagnostic image is hindered.
The present invention has been made in view of the above circumstances, and an object thereof is to provide an image reading apparatus capable of obtaining a good diagnostic image without image unevenness.

In order to solve the above problems, the invention of claim 1 is an image reading apparatus for reading image information by irradiating a stimulable phosphor sheet or a plate-like member attached with a stimulable phosphor sheet with excitation light. ,
An optical unit that reads the image information by condensing and photoelectrically converting the photostimulated luminescence emitted from the photostimulable phosphor sheet by irradiating the photostimulable phosphor sheet while scanning with excitation light from a light source;
A support member mounted on the main body frame via a vibration isolation member and supporting the optical unit so as to be movable in the horizontal direction;
A linear motor that moves the optical unit;
A guide member provided on the support member for guiding the optical unit in a horizontal direction;
The support member is provided with a balancer that balances with the optical unit and relatively moves in conjunction with the movement of the optical unit.

According to the first aspect of the present invention, the optical unit is moved in the horizontal direction along the guide member by the linear motor, and the balancer is moved in the direction opposite to the movement of the optical unit. Balance is kept in balance. As a result, unlike the conventional case, the vibration-proof member is not bent due to the weight of the optical unit, and the optical unit can be moved at a constant speed while being held in a horizontal state. Therefore, when the photostimulable phosphor plate is scanned with photostimulated excitation light, a good diagnostic image without image unevenness can be obtained.
Further, since the vibration isolating member is provided between the main body frame and the support member, the vibration isolating member can prevent vibration transmitted from the outside to the support member and the optical unit via the main body frame. it can. Therefore, the optical unit can be moved smoothly.

According to a second aspect of the present invention, in the image reading apparatus according to the first aspect,
The optical unit and the balancer are connected by a belt or a wire.

  According to the invention of claim 2, since the optical unit and the balancer are connected by the belt or the wire, the optical unit and the balancer can have a simple configuration and can be easily manufactured. Further, compared with a gear mechanism, for example, it is possible to suppress the occurrence of vibration due to the movement of the optical unit or the balancer, and it is possible to move at a constant speed.

The invention of claim 3 is the image reading apparatus according to claim 1 or 2,
The guide member is provided with a guided member that is guided by the guide member and is movable in the horizontal direction while supporting the optical unit or the balancer.
The position of the center of gravity of the optical unit substantially coincides with the center position of the guided member in the moving direction.

  According to the invention of claim 3, since the gravity center position of the optical unit or the balancer substantially coincides with the center position in the moving direction of the guided member, the optical unit can be moved in the most stable state. It is possible to move at a more uniform speed.

The invention of claim 4 is the image reading apparatus according to any one of claims 1 to 3,
The weights of the optical unit and the balancer are substantially equal.

  According to the invention of claim 4, since the weights of the optical unit and the balancer are substantially equal, the optical unit can be moved in the horizontal direction in a stable state.

According to the image reading apparatus of the present invention, the optical unit is moved along the horizontal direction of the guide member by the linear motor, and accordingly, the balancer is moved in the direction opposite to the movement of the optical unit. As a result, the balance of the center of gravity due to the movement of the optical unit is kept in balance.
Therefore, it is possible to move the optical unit at a constant speed while keeping the optical unit in a horizontal state, and to obtain a good diagnostic image without image unevenness when the photostimulable phosphor plate is scanned with photostimulated excitation light. Can do.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 is a perspective view of a transport mechanism in an image reading apparatus according to an embodiment of the present invention, FIG. 2 is a YZ plan view in FIG. 1, FIG. 3 is an XY plan view in FIG. 1, and FIG. 1 is an XZ plan view in FIG.
In the present invention, the stimulable phosphor sheet is not rigid by itself and is difficult to handle in the apparatus. It is supported by sticking it on a support such as a plate or by housing it in a removable case called a cassette and bonding it to the inner surface of the cassette. In this way, the structure in which the photostimulable phosphor sheet is supported by the support or the cassette is referred to as a photostimulable phosphor plate in the following description.
The photostimulable phosphor plate absorbs the radiation transmitted through the subject at the time of photographing, and a part of the energy is accumulated as information of the radiation image in the photostimulable phosphor. The image reading apparatus according to the present invention is an apparatus for reading information on a radiographic image accumulated in such a stimulable phosphor.

  As shown in FIGS. 1 to 4, the image reading apparatus irradiates a stimulable phosphor plate P while irradiating excitation light from a laser light irradiation device (light source) (not shown) while scanning the stimulable phosphor. The optical unit 1 that collects and photoelectrically converts the photostimulated light L2 emitted from the plate P to read image information, the support member 2 that supports the optical unit 1 so as to be movable in the horizontal direction, and the optical unit 1 are moved. A linear motor and guide members 31 and 32 provided on the support member 2 to guide the optical unit 1 in the horizontal direction are provided.

  The optical unit 1 includes a laser beam irradiation device that irradiates the photostimulable phosphor plate P while scanning the laser beam L1 in a direction orthogonal to the moving direction of the optical unit 1, and a stimulable fluorescence by the laser beam irradiation device. The light guide plate 13 that guides the stimulated emission light L2 excited from the stimulable phosphor plate P when the body plate P is irradiated with the laser light L1 and the stimulated emission light L2 that is guided by the light guide plate 13 are collected. It has a light collecting tube 11 and a photoelectric converter 12 such as a photomultiplier that converts the stimulated emission light L2 collected by the light collecting tube 11 into an electric signal.

The support member 2 is a long plate-like member extending in the horizontal direction, and is a substantially U-shaped body frame 8 having a substantially U-shaped cross-sectional view provided in the image reading apparatus in a substantially horizontal manner (in FIG. Only) and is fixed so as to be substantially horizontal via the vibration isolating member 4.
As shown in FIGS. 2 and 3, the vibration isolation member 4 is provided at the four corners of the lower surface of the support member 2, interposed between the upper surface of the main body frame 8 and the lower surface of the support member 2, and the support member 2 from the outside. And the vibration transmitted to the optical unit 1 is absorbed. Examples of the material of the vibration isolation member 4 include those made of an elastic material such as rubber.
Further, the photostimulable phosphor plate P is held so that the upper surface of the support member 2 and the laser light irradiation surface of the photostimulable phosphor plate P are substantially perpendicular. That is, this photostimulable phosphor plate P is transported into the image reading apparatus by a transport means (not shown), and then the support side surface (back surface) is fixed to the fixing plate 14 attached on the support member 2. Has been.
The support member 2 includes an optical unit 1 that can move in the longitudinal direction (horizontal direction) and a balancer 5 that balances the optical unit 1 via a connecting member 6 such as a steel wire. Are supported so as to be movable in opposite directions.
That is, as shown in FIG. 2, a first guide rail (guide member) 31 that guides the optical unit 1 in the horizontal direction is provided substantially at the center of the upper surface of the support member 2. The 2nd guide rail (guide member) 32 which guides 5 to a horizontal direction is provided. The first guide rail 31 and the second guide rail 32 are rod-shaped members having a substantially rectangular shape in cross section.

  A first guided member (guided member) 33 having a substantially U-shaped cross-section guided by the first guide rail 31 is engaged with the first guide rail 31. The first guided member 33 is fixed to the attachment member 35 on the lower end surface of the optical unit 1.

  Of the side of the mounting member 35, on the side facing the photostimulable phosphor plate P, a magnet portion 71 constituting a linear motor is supported by a support piece 72 formed integrally with the support member 2, and is horizontally It extends in the direction. The magnet portion 71 is formed in a shaft shape by connecting a plurality of N poles or S poles of a permanent magnet having a circular cross section.

  A movable coil 73 that constitutes the linear motor 7 is provided on the side of the mounting member 35. This movable coil 73 has a coil formed in a cylindrical shape, and this coil is covered with a box-shaped cover member. And the linear motor is comprised so that the magnet part 71 may penetrate the center of the movable coil 73. FIG.

  Further, a linear scale 74 constituting an encoder for detecting the position and moving speed of the optical unit 1 extends in the horizontal direction on the opposite side of the first guide rail 31 on the upper surface of the support member 2 from the magnet unit 71. Is provided. Further, on the other side portion of the attachment member 35, a sensor portion 75 that configures an encoder and reads the linear scale 74 at a position facing the linear scale 74 is provided.

A second guided member 32 (guided member) 34 having a substantially U-shaped cross section guided by the second guide rail 32 is engaged with the second guide rail 32 provided at the substantially center of the lower surface of the support member 2. ing. The second guided member 34 is attached to the upper end surface of the balancer 5. The balancer 5 is housed in the recess of the main body frame 8.
The material of the balancer 5 may be made of metal or resin, for example, and is not particularly limited. Moreover, it is preferable that the weight of the whole optical unit 1 and the weight of the balancer 5 are substantially equal.
Furthermore, it is preferable that the optical unit 1 and the balancer 5 substantially coincide with the center positions of the first guided member 33 and the second guided member 34 in the moving direction, respectively.

  On the other hand, as shown in FIGS. 1 and 3, two pulleys 61 on which the connecting member 6 is stretched are provided on each of the upper and lower surfaces of the support member 2 at both ends in the horizontal direction of the support member 2. . That is, at one end in the horizontal direction of the support member 2, the upper pulley 61 a on the upper surface side of the support member 2, the lower pulley 61 b on the lower surface side, and the upper surface of the support member 2 at the other horizontal end of the support member 2. An upper pulley 61a is provided on the side, and a lower pulley 61b is provided on the lower surface side. The pulleys 61 a and 61 b are held by fixing a holding plate 63 that holds the shaft portion 62 of each pulley 61 a and 61 b to the support member 2. The connecting member 6 is stretched between the pulleys 61a and 61b, the attachment member 35 of the optical unit 1 is fastened to the connecting member 6 on the upper surface side of the support member 2, and the balancer 5 is fastened to the connecting member 6 on the lower surface side. Yes.

  In the image reading apparatus of the present invention, although not shown, the photostimulable phosphor is used to release the radiation energy remaining in the photostimulable phosphor plate P after the radiation energy is read by the optical unit 1. An erasing device that irradiates the plate P with erasing light is provided.

Next, the operation of the image reading apparatus configured as described above will be described.
The photostimulable phosphor plate P is taken into the image reading apparatus by the conveying means and fixed to the fixing plate 14. When performing an image reading process, first, the linear motor is driven to move the optical unit 1 along the first guide rail 31. In conjunction with the movement of the optical unit 1, the balancer 5 moves in the horizontal direction along the second guide rail 32 in the direction opposite to the optical unit 1.
As a result, the optical unit 1 is moved to a position facing the laser light irradiation surface of the photostimulable phosphor plate P, and is moved from the laser light irradiation device while moving along the horizontal direction of the photostimulable phosphor plate P. The light L1 is scanned. At this time, the laser beam L1 is irradiated while scanning in a direction orthogonal to the moving direction of the optical unit 1. As a result, the excited stimulated emission light L2 is guided by the light guide plate 13 and condensed on the condenser tube 11, and converted into an electric signal by the photoelectric converter 12.

  The operation of the linear motor is controlled based on the detection result by the encoder, and the optical unit 1 is moved at a constant speed so that the laser beam L1 is accurately scanned.

When the reading process by the optical unit 1 is completed up to one end of the photostimulable phosphor plate P, the linear motor is stopped.
Thereafter, the photostimulable phosphor plate P is irradiated with erase light by an eraser (not shown), thereby erasing the radiation image remaining on the photostimulable phosphor plate P. Further, the stimulable phosphor plate P is transported to the outside of the image reading device by the transporting means.

As described above, according to the image reading apparatus of the embodiment of the present invention, the optical unit 1 is moved in the horizontal direction along the first guide rail 31 by the linear motor, and accordingly, the direction opposite to the movement of the optical unit 1. The balancer 5 moves in the horizontal direction along the second guide rail 32. As a result, the balance of the center of gravity due to the movement of the optical unit 1 is kept in balance, and unlike the conventional case, the vibration isolating member 4 is not bent due to the weight of the optical unit 1, and the optical unit 1 is held in a horizontal state. , Can be moved at the same speed. Therefore, when the photostimulable phosphor plate P is scanned with the laser light L1, a good diagnostic image without image unevenness can be obtained.
Further, since the vibration isolating member 4 is provided between the main body frame 8 and the support member 2, the vibration isolating member 4 transmits the vibration to the support member 2 and the optical unit 1 from the outside via the main body frame 8. Vibration can be prevented. Therefore, the optical unit 1 can be moved smoothly.
Moreover, since the optical unit 1 and the balancer 5 are connected by the wire 6, it can be set as a simple structure and manufacture is easy. Further, by adopting such a structure, generation of vibration due to movement of the optical unit 1 and the balancer 5 can be suppressed, and movement at a constant speed becomes possible.
Furthermore, the center of gravity of the optical unit 1 or the balancer 5 substantially coincides with the center position of the first guided member 33 or the second guided member 34 in the moving direction, so that the optical unit 1 or the balancer 5 is most stable. In this respect, it is possible to move at a constant speed.
Moreover, since the weight of the optical unit 1 and the balancer 5 is substantially equal, the optical unit 1 can be moved in the horizontal direction in a stable state. In addition, since the optical unit 1 and the balancer 5 are configured to be movable by a single guide member including the first guide rail 31 and the second guide rail 32, the entire apparatus can be reduced in size and cost. Can do.

In addition, embodiment of this invention is not limited to the said embodiment, Unless it changes the summary, it can change suitably.
In the above embodiment, the optical unit 1 and the balancer 5 are provided on the upper and lower surfaces with the support member 2 interposed therebetween. However, the optical unit 1 and the balancer 5 are provided on the same surface of the support member 2, for example, on the upper surface of the support member 2. Each of the optical units 1 and the balancer 5 may be provided so as to be movable in opposite directions. In this case, the second guide rail 32 provided on the lower surface of the support member 2 is provided in parallel with the first guide rail 31 on the upper surface of the support member 2, and the balancer 5 is horizontally moved by the second guide rail 32. Move it.

The optical unit 1 and the balancer 5 are configured to be movable by a single guide member made up of the first guide rail 31 and the second guide rail 32. The unit 1 and the balancer 5 may be configured to be movable by a plurality of guide members. Further, the shapes of the first and second guide rails 31 and 32 and the first and second guided members 33 and 34 are not limited to the rod-like members having a substantially rectangular shape in cross section, and may be in a substantially circular shape in cross section.
Furthermore, in the said embodiment, although the steel wire was used as the connection member 6, you may use a belt etc., for example.

FIG. 3 is a perspective view of a transport mechanism in the image reading apparatus for illustrating an embodiment of the present invention. It is a YZ top view in the conveyance mechanism of FIG. FIG. 2 is an XY plan view of the transport mechanism in FIG. 1. FIG. 2 is an XZ plan view of the transport mechanism in FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical unit 2 Support member 4 Anti-vibration member 5 Balancer 6 Wire 8 Main body frame 31 1st guide rail (guide member)
32 Second guide rail (guide member)
33 First guided member (guided member)
34 Second guided member (guided member)
L1 Laser light (excitation light)
L2 photostimulated light

Claims (4)

In an image reading apparatus for reading image information by irradiating a stimulable phosphor sheet or a plate-like member attached with a stimulable phosphor sheet with excitation light, the stimulable phosphor sheet is scanned with excitation light from a light source. An optical unit that reads the image information by condensing and photoelectrically converting the photostimulated luminescence emitted from the photostimulable phosphor sheet while being irradiated,
A support member mounted on the main body frame via a vibration isolation member and supporting the optical unit so as to be movable in the horizontal direction;
A linear motor that moves the optical unit;
A guide member provided on the support member for guiding the optical unit in a horizontal direction;
The image reading apparatus according to claim 1, wherein the support member is provided with a balancer that balances with the optical unit and relatively moves in conjunction with the movement of the optical unit.   The image reading apparatus according to claim 1, wherein the optical unit and the balancer are connected by a belt or a wire. The guide member is provided with a guided member that is guided by the guide member and is movable in a horizontal direction while supporting the optical unit or the balancer.
3. The image reading apparatus according to claim 1, wherein a position of the center of gravity of the optical unit substantially coincides with a center position in a moving direction of the guided member.   The image reading apparatus according to claim 1, wherein weights of the optical unit and the balancer are substantially equal.

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