Photocopying – Projection printing and copying cameras – Identifying – composing – or selecting
Reexamination Certificate
2000-09-18
2001-07-10
Adams, Russell (Department: 2851)
Photocopying
Projection printing and copying cameras
Identifying, composing, or selecting
C355S043000, C355S047000, C355S049000, C355S057000, C355S065000, C250S580000, C250S581000, C250S582000, C250S586000, C250S587000
Reexamination Certificate
active
06259507
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a radiation image read-out apparatus, wherein a stimulable phosphor sheet, on which a radiation image has been stored, is exposed to stimulating rays, and an image signal representing the radiation image is detected from the stimulable phosphor sheet.
2. Description of the Related Art
It has been proposed to use stimulable phosphors in radiation image recording and reproducing systems. Specifically, a radiation image of an object, such as a human body, is recorded on a sheet provided with a layer of the stimulable phosphor (hereinafter referred to as a stimulable phosphor sheet). The stimulable phosphor sheet, on which the radiation image has been stored, is then exposed to stimulating rays, such as a laser beam, which cause the stimulable phosphor sheet to emit light in proportion to the amount of energy stored thereon during its exposure to the radiation. The light emitted by the stimulable phosphor sheet, upon stimulation thereof, is photoelectrically detected with photoelectric read-out means, such as a photomultiplier, and converted into an electric image signal. The image signal is then processed and used for the reproduction of the radiation image of the object as a visible image on a recording material.
In the radiation image recording and reproducing systems described above, the light is emitted in a scattering state from the stimulable phosphor sheet. Therefore, alight guide member and a light guiding mirror are located in the vicinity of the position that is exposed to the stimulating rays. The light emitted in the scattering state from the stimulable phosphor sheet is reflected by the light guiding mirror toward the light guide member. In this manner, the efficiency, with which the emitted light is collected, is enhanced.
The light guiding mirror described above is supported by support means, which is formed from a metal. The support means is secured by screws, or the like, to a frame within a radiation image read-out apparatus. Therefore, the support means is in a grounded state (i.e., in the state in which the support means is electrically connected with a ground). In cases where the radiation image is read out from the stimulable phosphor sheet having been charged electrostatically, lines of electric force concentrate upon the support means, and dust clinging to the stimulable phosphor sheet clings to the light guiding mirror by electrostatic adsorption. If the dust clings to the light guiding mirror in this manner, the stimulating rays will be eclipsed by the dust. In such cases, since the stimulable phosphor sheet is also scanned with the stimulating rays in a sub-scanning direction, streak-like nonuniformity in image density occurs in the sub-scanning direction. Also, the light guiding mirror is formed with, for example, a technique, wherein a dichroic coating layer is formed on a glass substrate. Therefore, the light guiding mirror is adhered to the support means with an adhesive agent. In such cases, if the adhesive agent protrudes from the area of adhesion of the light guiding mirror and dust clings to the protruding adhesive agent, it will become difficult to remove the dust.
SUMMARY OF THE INVENTION
The primary object of the present invention is to provide a radiation image read-out apparatus, wherein dust is capable of being prevented from clinging to a light guiding mirror.
Another object of the present invention is to provide a radiation image read-out apparatus, wherein dust is capable of being prevented from clinging to a light guiding mirror, and a cost of the radiation image read-out apparatus is capable of being kept low.
The present invention provides a first radiation image read-out apparatus, comprising:
i) main scanning means for scanning a stimulable phosphor sheet, on which a radiation image has been stored, with stimulating rays in a main scanning direction, the stimulating rays causing the stimulable phosphor sheet to emit light in proportion to an amount of energy stored thereon during its exposure to radiation,
ii) sub-scanning means for scanning the stimulable phosphor sheet in a sub-scanning direction, which is approximately normal to the main scanning direction,
iii) read-out means for photoelectrically detecting the light, which is emitted by the stimulable phosphor sheet when the stimulable phosphor sheet is scanned with the stimulating rays in the main scanning direction, and obtaining an image signal representing the radiation image,
iv) a light guiding mirror for reflecting the emitted light toward the read-out means, the light guiding mirror being located to extend in the main scanning direction at a position in the vicinity of a position on the stimulable phosphor sheet, which position is scanned with the stimulating rays in the main scanning direction, and
v) support means for supporting the light guiding mirror,
wherein the support means is formed from a metallic material and is electrically isolated from a ground.
In the first radiation image read-out apparatus in accordance with the present invention, the support means is electrically isolated from the ground. Specifically, the support means is in the state in which the support means is not grounded.
In the first radiation image read-out apparatus in accordance with the present invention, the light guiding mirror should preferably be constituted of a film-shaped member.
The term “film-shaped member” as used herein means the member, which does not have rigidity and has flexibility.
Also, in the first radiation image read-out apparatus in accordance with the present invention, the light guiding mirror should preferably be constituted of a filter, which absorbs the stimulating rays and has been subjected to mirror surface processing.
In the first radiation image read-out apparatus in accordance with the present invention, wherein the light guiding mirror is constituted of the film-shaped member, the support means should preferably be means for engaging with upper and lower ends of the light guiding mirror, such that the light guiding mirror is curved in a concave form.
The term “upper and lower ends of a light guiding mirror” as used herein means the two longitudinal side regions of the light guiding mirror, which extends in the main scanning direction. Therefore, with the support means, which is constituted to engage with the upper and lower ends of the light guiding mirror, the light guiding mirror is curved in the concave form, as viewed in a cross-section normal to the main scanning direction, and is thus curved into a cylindrical mirror-like shape.
The present invention also provides a second radiation image read-out apparatus, comprising:
i) main scanning means for scanning a stimulable phosphor sheet, on which a radiation image has been stored, with stimulating rays in a main scanning direction, the stimulating rays causing the stimulable phosphor sheet to emit light in proportion to an amount of energy stored thereon during its exposure to radiation,
ii) sub-scanning means for scanning the stimulable phosphor sheet in a sub-scanning direction, which is approximately normal to the main scanning direction,
iii) read-out means for photoelectrically detecting the light, which is emitted by the stimulable phosphor sheet when the stimulable phosphor sheet is scanned with the stimulating rays in the main scanning direction, and obtaining an image signal representing the radiation image,
iv) a light guiding mirror for reflecting the emitted light toward the read-out means, the light guiding mirror being located to extend in the main scanning direction at a position in the vicinity of a position on the stimulable phosphor sheet, which position is scanned with the stimulating rays in the main scanning direction, and
v) support means for supporting the light guiding mirror,
wherein the support means is formed from an electrical insulating material.
As the electrical insulating material, a material having an electrical resistivity of at least 1×10
2
&OHgr;m may be employed. Examples of the ele
Adams Russell
Brown Khaled
Fuji Photo Film Co. , Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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