JPH10178514A - Radiation image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To read stably image information even in the case that a carrying direction of a stimulable phosphor sheet in a read section is set to a vertical direction in a radiation image reader. SOLUTION: A leaf spring 40 extended over from one end of a stimulable phosphor sheet A in the width direction to another end is fixed to a mirror mount 39a supporting a collecting light mirror 39, the leaf spring 40 presses the sheet A onto a guide plate 75 close to an emission position P of a stimulating light Lx so as to make a state of the sheet A stable at the light emission position P and the vicinity and a collecting light system consisting of the collecting light mirror 39 and a light guide 38 collects a stimulating light Ly from the laser light irradiating position P to read radiation image information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation image reading apparatus, and more particularly, to a stable radiation image reading apparatus which does not generate reading unevenness when condensing photostimulated light emitted from a stimulable phosphor sheet to read image information. The present invention relates to a radiation image reading apparatus capable of reading.

[0002]

2. Description of the Related Art Heretofore, a part of this radiation energy has been accumulated when irradiated with radiation, and subsequently, when irradiated with excitation light such as visible light, a stimulable phosphor sheet which exhibits stimulated emission according to the accumulated energy. Is used to record radiation image information of a subject such as a human body and to further obtain this image information as a visible image.

In this case, the radiation image information stored and recorded on the stimulable phosphor sheet (hereinafter simply referred to as “sheet”) is obtained by photoelectrically reading stimulated emission light generated when the sheet is irradiated with excitation light. Is reproduced as a visible image by a recording material such as a photographic photosensitive material or a CRT based on the image signal obtained by the above. The sheet from which the radiation image information is read in this way can be reused because the radiation image information is erased by irradiating the sheet with erasing light from an erasing light source such as a fluorescent lamp or a tungsten lamp. Become.

A device for reading the radiation image information from the sheet on which the radiation image information is recorded as described above generally includes a cassette holding portion for detachably holding a cassette in which the sheet is freely inserted and removed, and A reading unit for reading the radiation image information as described above, and an erasing unit for erasing the radiation image information after the reading, and transporting the cassette from the cassette held in the cassette holding unit to the reading unit, After reading the radiation image information, the sheet is conveyed to an erasing unit, and after erasing the radiation image information in the erasing unit, the sheet is conveyed toward the cassette and stored again in the cassette. (Japanese Patent Laid-Open No.
320252, JP-A-5-297489, etc.).

A reading section of such a radiation image reading apparatus generally has a configuration in which a sheet is conveyed in a horizontal direction, that is, an image is read by irradiating radiation in a state in which the sheet is sub-scanned in a horizontal direction. (See FIG. 5). Normally, the sheet has a slight curl at the leading end and the trailing end, and the curl may cause the sheet to float and the image reading state may become unstable. Therefore, in order to read the image stably without unevenness, the guide plate 10 is arranged on the back side of the sheet, and the number of scanning lines on the sheet A is reduced by two pairs of rollers 5 (5a, 5b) and 6 (6a, 6b). Sub-scanning conveyance is performed with the nip at a position separated by centimeters. Further, if a sheet has an impact when the sheet enters or exits the roller pair, unevenness in image information reading occurs. Therefore, the nip rollers 5a and 6a are movable up and down, and when the sheet A enters the pair of rollers 5 and 6, the nip rollers 5a and 6a are moved upward so as not to apply an impact to the sheet after entering the sheet. Return to the normal position and nip the sheet. Similarly, at the time of discharging the sheet, the nip rollers 5a and 6a are moved upward to prevent an impact. In this manner, the irradiation position of the radiation L on the sheet is stabilized to perform image reading and reading without unevenness. Note that the arrow Y in the figure is the transport direction.

[0006]

However, due to the structure of the apparatus, for example, in order to reduce the size of the apparatus, there is a case where it is desired to read the image while the sheet is conveyed vertically in the reading section. is there. In such a case, the configuration is the same as the case where the sheet is conveyed in the horizontal direction as described above. For example, the case where the sheet A is sub-scanned vertically downward (arrow Z direction) as shown in FIG. When the nip roller 5a moves and the sheet is released from the gripping state when the trailing end of the sheet A is discharged from the roller pair 5 (5a, 5b) on the downstream side, the movement of the nip roller 5a The edges fall down due to curling. As a result, the irradiation position of the radiation L on the sheet A becomes unstable, and adverse effects such as unevenness in image reading occur.

[0007] The present invention has been made in view of the above circumstances, and has as its object to provide a radiation image reading apparatus capable of always performing stable image reading.

[0008]

According to the radiation image reading apparatus of the present invention, a pair of rollers for nipping and transporting a stimulable phosphor sheet on which radiation image information is stored are shorter than the length of the sheet in the transport direction. Two pairs are arranged at intervals, and the two pairs of rollers are used for sub-scanning conveyance, and the pair of rollers is irradiated with excitation light deflected in a direction substantially perpendicular to the sub-scanning conveyance direction to perform main scanning. And irradiating the radiation image information in two dimensions by condensing stimulated emission light emitted from at least the surface of the sheet by irradiating the excitation light from a light condensing system positioned close to the sheet. In the radiation image reading apparatus, the light condensing system includes a light guide for guiding the photostimulated light to a photodetector, and a condensing device for reflecting the photostimulated light toward an incident end face of the light guide. With mirror A guide plate that supports the back surface of the sheet is disposed between the pair of rollers, and a part of a mirror mount that supports the condensing mirror includes the sheet on the guide plate near the irradiation position of the excitation light. A leaf spring for pressing and extending from one end of the sheet in the width direction to the other end is fixedly provided.

That is, the radiation image reading apparatus of the present invention stabilizes the sheet by reading the radiation image information from the stimulable phosphor sheet by pressing the sheet on the guide plate in the vicinity of the condensing system. The information reading accuracy is improved.

The direction of the sub-scanning conveyance is not limited to the vertical direction.

[0011] The portion of the leaf spring that contacts the sheet is
It is made of a material that does not hinder the sheet and does not hinder the smooth conveyance of the sheet, or a portion of the leaf spring that contacts the sheet, without damaging the sheet, and It is desirable that a material that does not hinder proper transport be provided.

The leaf spring presses the sheet with a force that does not hinder sheet conveyance when the sheet is pressed onto the guide plate and that does not damage the sheet.

[0013]

The radiation image reading apparatus of the present invention accumulates in the vicinity of the irradiation position of the excitation light by a plate spring fixed to a part of a mirror mount that supports a condenser mirror which is a part of a condenser system. With the configuration in which the stimulable phosphor sheet is pressed against the guide plate and the radiation image is read from the stimulable phosphor sheet, more stable image reading is possible even in the case of a configuration in which the sub-scanning is performed in the horizontal direction. Even in the case of a configuration in which vertical scanning is performed, the sheet can be stably maintained without fluctuation at the excitation light irradiation position of the sheet, and as a result, stable image reading without unevenness can be performed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a specific embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic sectional view of the radiation image reading apparatus of the present embodiment, and FIGS. 2 and 3 are a perspective view and a sectional view showing a schematic configuration of a reading section of the radiation image reading apparatus of FIG.

As shown in FIG. 1, the radiation image reading apparatus includes a stimulable phosphor sheet A (hereinafter simply referred to as a sheet).
And a cassette holding unit 20 for detachably holding a cassette B in which the cassette B is stored so as to be freely inserted and removed, and radiation image information accumulated and recorded on the sheet A (hereinafter simply referred to as image information or image).
A reading unit 30 for reading the image information, an erasing unit 50 for erasing the image information, and loading the sheet A into the reading unit 30 from the cassette B held in the cassette holding unit 20; A sheet conveying means 60 for carrying in the cassette B from the inside of the cassette B via the erasing section 50;

The cassette holding section 20 has an opening 21 into which one end of the cassette B provided with the opening / closing lid b can be inserted and an instruction plate 22 for detachably holding the cassette B in a horizontal posture. The cassette holding portion 20 is configured to open and close the opening / closing lid b of the cassette B by a lid opening / closing mechanism (not shown) when one end of the cassette B is fitted into the opening 21.

The sheet conveying means 60 conveys the sheet A from the cassette B to the erasing section 50 and the reading section 30 by carrying in and out rollers 61 provided near the opening 21 of the cassette holding section 20. Conversely, cassette B from reading unit 30 through erasing unit 50
Roller pairs 62 to 67 for conveying the sheet A and guide members 70 to 74 for guiding the sheet. A pair of rollers 66 (66a, 66b), 67 arranged near the image reading position P of the reading unit 30
One of the rollers (67a, 67b) is a nip roller having a slow-up / down mechanism (not shown), and is movable in a direction away from the paired rollers 66b, 67b. These nip rollers 66a, 67a
When the sheet enters the roller pair 66, 67 and when the roller pair
When the sheet is discharged from 66, 67, the sheet moves in the separating direction (the direction of arrow Y).

The reading section 30 includes an excitation light irradiating means 31 for irradiating the sheet A with excitation light Lx such as a laser beam, and the excitation light L
stimulable light L emitted from the sheet A upon irradiation of x
and a photoelectric reading unit 36 for receiving the y and reading the image information stored and recorded on the sheet A.

An excitation light irradiating means 31 emits a laser light Lx having a predetermined wavelength, and reflects and deflects the emitted laser light Lx to apply the laser light Lx to the sheet A by an arrow X.
Polygon mirror 34 for main scanning in the direction, a motor 33 for rotating the polygon mirror 34, and a laser beam Lx reflected and deflected by the polygon mirror 34 converge to a predetermined irradiation position P on the sheet A, and The scanning lens 35 scans at a constant speed.

The photoelectric reading means 36 includes a condensing system for condensing stimulated emission light Ly emitted from the sheet A on which image information is recorded when the sheet A on which image information is recorded is irradiated with the laser light Lx at the irradiation position P. A photomultiplier 37 receives the condensed stimulated emission light Ly, reads the image information of the sheet A, photoelectrically converts it into an image signal S, and outputs this to an external device (not shown). Here, the condensing system includes a light guide 38 projecting from the light receiving surface of the photomultiplier 37 toward the laser beam irradiation position P of the sheet A and condensing the photostimulated light Ly. Light guide 38 for light Ly efficiently
And a converging mirror 39 extending in the main scanning direction of the laser beam Lx and guided to the incident end face of the laser beam Lx. In addition, focusing mirror
39 is supported by a mirror mount 39a. Further, a guide plate 75 is provided on the back side of the sheet at the irradiation position P to support the sheet when reading an image.

Further, in order to stabilize the state of the laser beam irradiation position P on the sheet A at the time of image reading, the mirror mount 39a is located at a distance r from the irradiation position P to the upstream side in the sub-scanning conveyance. The leaf spring 40 for pressing the sheet against the guide plate 75 is fixedly provided. The leaf spring 40 is specifically arranged so as to press the sheet A at a position of 3 to 5 mm from the scanning line, that is, at a position of r = 3 to 5 mm. The leaf spring 40 presses the sheet A against the guide plate 75 from one end to the other end in the width direction of the sheet A to support the sheet A. The contact portion with the sheet A damages the sheet A. A material (sliding material) 41 that does not hinder the smooth conveyance of the sheet A is provided (see FIG. 4). Specifically, as shown in FIG. 4, the leaf spring 40 has a total length of about 15 mm, of which about 5 mm is fixed to the mirror mount 39a. As the leaf spring 40, a PET sheet having a thickness of 190 μm is used, and as the sliding member 41, for example, a light emitting Stratec is used.

The erasing section 50 includes an erasing light source 51 such as a fluorescent lamp or a tungsten lamp for irradiating the erasing light Lz, and a semicircular reflector 52 provided above the erasing light source 51.

Next, the operation of the radiation image information reading apparatus thus configured will be described.

Image information of a human body or the like is recorded on the cassette B.
When reading image information from the sheet A stored in the cassette B, the cassette B is first held horizontally by the cassette holding unit 20, and the radiation image reading apparatus is driven in this state.

The sheet A is first unloaded from the cassette B by the unloading and loading rollers 61, and the unloaded sheet is received by the pair of rollers 62, and is sent to the reading section 30 via the erasing section 50 in which the erasing light source 51 is turned off. and it is guided by the guide members 70,71,72,73,74, by rollers 63,64,65,66,67, one end a ₂ of the sheet a is conveyed until the position in the laser beam irradiation position P.

The image reading is started from the state in which one end A ₂ is located in the sheet A to the laser beam irradiation position P. Excited light Lx is irradiated to the irradiation position P by the excitation light irradiating means 31, rollers 66, 67 gradually conveyed in the opposite direction by, i.e. vertically downward is sub scanning (arrow Z direction) the other from one end A ₂ sheets sequentially laser light irradiation is performed towards the end A _2. At the time of irradiation with the excitation light Lx, the stimulating light Ly is emitted from the sheet A at the irradiation position P in accordance with the accumulated and recorded image information. The emitted light Ly is received by the photomultiplier 37, so that the image information is read sequentially toward the other end portion A ₂ from the sheet end portion A _1.

The sheet A, first roller pair 67 is conveyed in the Z direction by being image reading is performed, the nip roller 66a is in one end A ₁ of the sheet A enters the rollers 66 are once moved in the direction of arrow Y The sheet A smoothly enters the roller pair 66, and then the nip roller 66a returns to the original position and nips the sheet A.
The image is read while being conveyed while being gripped by the and 67. At this time, the seat A
Since the sheet is conveyed (sub-scanned) while being pressed by the guide plate 75 at a position on the upstream side r from the laser beam irradiation position P by the plate spring 40 fixed to the laser beam 39a, the sheet state at the irradiation position P becomes stable and uneven. Image reading is performed. Then, when the other end A ₂ of the sheet A is discharged from the roller pair 67 is discharged sheets A without impacting the sheet A moves the nip roller 67a is in the direction of the arrow Y is effected smoothly.
Thus sheet A be released from the holding state by the roller pair 67, because it is pressed against the guide plate 75 by the leaf spring 40, without being affected by curling from the sheet and the other end A ₂ to a position a distance r Image reading without unevenness can be performed.

Hereinafter, the force generated in the leaf spring 40 will be specifically described with reference to examples.

For example, when the Young's modulus E of the stimulable phosphor sheet used is E = 3.4 [GPa] and the sheet is placed vertically, if the curl is such that the leading end is separated from the vertical position by about 10 mm. I do. At this time, the force W required to keep the sheet vertically back curl from W = 3EIv / l ^3, 0.28
kg. Here, I is the second moment of area, v is the amount of deflection of the sheet (here, 10 mm), and l is the width of the sheet. On the other hand, the force generated by the leaf spring 40 used in the present embodiment is theoretically about W = 600 g, which is sufficient strength to press the sheet A against the guide plate 75 so as to support the sheet A vertically. It is.

The sheet A is conveyed to the erasing section 50 from the reading unit 30, from the one end A ₁ read the image information of the sheet A at the erasing section 50 of the image information remaining toward the other end portion A ₂ Erasure is performed. That is, the erasing light source 51
Erasing light Lz emanating from and the sequentially irradiated onto the sheet A from the first end A ₁ toward the other end portion A _2, the radiation image information remaining on the sheet A is gradually erased gradually .

In this way, when the sheet A passes through the erasing section 50 and is returned to the cassette B, the image information has been completely erased, and the cassette B in which the sheet A is stored again is held in the cassette. By removing from part 20,
The sheet A can be reused.

In the present embodiment, the reading unit is a one-sided condensing reading unit that condenses stimulated emission light only from the surface.
The present invention is not limited to this mode, and may be a double-sided condensing reading unit that condenses stimulated emission light also from the back surface.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a schematic configuration of a radiation image reading apparatus according to the present invention.

FIG. 2 is a perspective view schematically showing a reading unit of the radiation image reading apparatus.

FIG. 3 is a sectional view schematically showing a reading unit of the radiation image reading apparatus.

FIG. 4 is a view showing a leaf spring fixed to a mirror mount.

FIG. 5 is a schematic configuration diagram of a reading unit of a conventional radiation image reading apparatus.

FIG. 6 is a diagram illustrating a problem when a sub-transport direction in a reading unit of a conventional radiation image reading apparatus is a vertical direction.

[Explanation of symbols]

 20 Cassette holding unit 30 Reading unit 31 Excitation light irradiation means 36 Reading means 37 Photomultiplier 38 Light guide 39 Condensing mirror 39a Mirror mount 40 Leaf spring 41 Sliding material 50 Erasing unit 60 Sheet transport means 61,62,63,64 , 65, 66, 67 Roller pair 66a, 67a Nip roller 75 Guide plate A A stimulable phosphor sheet

Claims (4)

[Claims] 1. A pair of rollers for sandwiching and transporting a stimulable phosphor sheet on which radiographic image information is stored and recorded at an interval shorter than the length of the sheet in the transport direction, and the two pairs of rollers are arranged. The main scanning is performed by irradiating excitation light deflected in a direction substantially orthogonal to the sub-scanning conveyance direction between the pair of rollers while performing the main scanning, and the excitation light is irradiated between the pair of rollers. A radiation image reading apparatus for two-dimensionally reading the radiation image information by condensing stimulated emission light emitted from at least the surface of the sheet from a light condensing system positioned close to the sheet, Comprises a light guide for guiding the stimulated emission light to a photodetector, and a condensing mirror for reflecting the stimulated emission light toward an incident end face of the light guide, and a guide for supporting a back surface of the sheet. Board in front A part of a mirror mount that is disposed between a pair of rollers and supports the light-collecting mirror, and presses the sheet onto the guide plate near the irradiation position of the excitation light, from one end to the other end in the width direction of the sheet. A radiation image reading apparatus, wherein a leaf spring extending in a direction is fixedly provided. 2. The radiation image reading apparatus according to claim 1, wherein the direction of the sub-scanning conveyance is a vertical direction. 3. The sheet spring according to claim 1, wherein a portion of the leaf spring in contact with the sheet is made of a material that does not damage the sheet and does not hinder smooth conveyance of the sheet. Or a radiation image reading apparatus according to the above. 4. The sheet spring according to claim 1, wherein a material that does not damage the sheet and does not prevent smooth conveyance of the sheet is disposed in a portion of the leaf spring that contacts the sheet. Or a radiation image reading apparatus according to the above.