JPH1184551A - Method and device for image read-out - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably detect the tip of a sheet without taking the attaching position of a detecting means into consideration at the time of detecting the tip of a stimulable phosphor sheet. SOLUTION: Stimulated phosphorescent light 13a generated by radiating a laser beam 11 to a sheet is reflected by a condensing mirror 7 having a characteristic to reflect only the stimulated phosphorescent light 13a and is condensed at a condensing guide 14a. A sensor detecting the laser beam 11 reflected by the sheet is provided at a mirror mount 6 supporting the condensing mirror 7. When the sheet is carried at the radiation position of the laser beam 11, the laser beam 11 is reflected by the sheet, and reflected light is transmitted through the condensing mirror 7 and is detected by the sensor, so that the tip of the sheet is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading method and apparatus for irradiating a stimulable phosphor sheet on which a radiation image is accumulated and recorded with excitation light and obtaining an image signal representing the radiation image from the sheet. .

[0002]

2. Description of the Related Art A recorded radiographic image is read to obtain an image signal, and the image signal is subjected to appropriate image processing.
2. Description of the Related Art Reproduction and recording of images are performed in various fields.
For example, an X-ray image is recorded using a film having a low gamma value designed to be compatible with later image processing, and this X-ray image is recorded.
The X-ray image is read from the film on which the line image is recorded, converted into an electric signal, the electric signal (image signal) is subjected to image processing, and then reproduced as a visible image in a copy photograph or the like, so that the contrast and sharpness are improved. A system capable of obtaining a reproduced image having good image quality performance such as graininess has been developed (see Japanese Patent Publication No. 61-5193).

[0003] Further, according to the present applicant, radiation (X-ray, α
Rays, β-rays, γ-rays, electron beams, ultraviolet rays, etc.), a part of this radiation energy is accumulated, and then, when irradiated with excitation light such as visible light, the amount of stimulated emission light corresponding to the accumulated energy is increased. Phosphor that emits light (stimulable phosphor)
Utilizing, a radiographic image of a subject such as a human body is once photographed and recorded on a sheet-shaped stimulable phosphor, and the stimulable phosphor sheet is scanned with excitation light such as laser light to generate stimulated emission light,
A radiation recording / reproducing system that photoelectrically reads the obtained stimulated emission light to obtain an image signal, and outputs a radiation image of a subject as a visible image to a recording material such as a photographic photosensitive material or a CRT based on the image signal. Have already been proposed (JP-A-55-12429, JP-A-56-11395, JP-A-55-0163472,
Nos. 56-164645 and 55-116340). In such a radiation image recording / reproducing system, the stimulating light is scattered and emitted from the stimulable phosphor sheet, so that the stimulating light is irradiated with excitation light in order to efficiently collect the scattered stimulating light. A light-collecting guide and a light-collecting mirror are provided near the position,
The scattered stimulated emission light is reflected toward the light-collecting guide by the light-collecting mirror and is collected by the light-collecting guide.

In a radiation image information recording / reproducing system using such a stimulable phosphor sheet, a photoelectric reading means is provided on both sides of the stimulable phosphor sheet as a method of photoelectrically reading stimulated emission light. Then, both sides or only one side of the stimulable phosphor sheet is scanned with excitation light, and the stimulated emission light emitted by this excitation light scanning is photoelectrically read from both sides of the stimulable phosphor sheet. (For example, see Japanese Patent Application Laid-Open No. 55-87970). Such a double-sided condensing reading method is applicable to a stimulable phosphor sheet.
Since two radiation images are accumulated and recorded, and stimulated emission light is condensed from both sides of the stimulable phosphor sheet, the light collection efficiency is improved and the S / N ratio is further improved.

On the other hand, in the above-described radiation image reproducing system, a plurality of stimulable phosphor sheets obtained by photographing the same subject are respectively scanned to obtain a plurality of image signals. When performing a superimposition process for obtaining an image having a high / N ratio or a high contrast, or a subtraction process for removing a part of an image from a certain image, it is necessary to perform scanning by accurately matching the starting end of each scan. is there. For this reason, a method for detecting the leading end of the stimulable phosphor sheet has been proposed in, for example, JP-A-58-31662. In the method described in Japanese Patent Application Laid-Open No. 58-31662, when the tip of the stimulable phosphor sheet is scanned by the excitation light, the reflection of the excitation light by the tip is detected by a sensor or the like, and the stimulable phosphor sheet is detected. In this case, the leading end of the body sheet is detected.

[0006]

The method described in Japanese Patent Application Laid-Open No. 58-31662 requires a sensor for detecting the reflected light. In a reading device provided with a light collecting mirror and a light collecting guide for detection, there is no flexibility in the mounting position of the sensor, and the mounting restrictions are severe. For this reason, the mounting position of the sensor is limited, and stable tip detection cannot be performed at the limited position. In particular, in an apparatus employing the above-described double-sided reading method, a light-collecting guide is also provided on the back side of the stimulable phosphor sheet, so that the mounting position of the sensor is further restricted.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an image reading method and apparatus capable of stably detecting the leading end of a stimulable phosphor sheet.

[0008]

According to a first image reading method of the present invention, a stimulable phosphor sheet on which a radiation image is accumulated and recorded is main-scanned with excitation light, and the stimulable phosphor sheet is scanned with the stimulable phosphor sheet. The radiation image is converted into photostimulated light by sub-scanning in a direction substantially perpendicular to the scanning direction, and photostimulated light obtained from the stimulable phosphor sheet is irradiated with the excitation light in the stimulable phosphor sheet. In the image reading method, the light is reflected and condensed by a converging mirror disposed in the vicinity of a portion to be read, and the condensing mirror transmits photoelectrically reflected excitation light reflected by the stimulable phosphor sheet. When the leading end of the stimulable phosphor sheet is main-scanned by the excitation light, the reflected excitation light transmitted through the converging mirror among the reflected excitation light by the leading end of the stimulable phosphor sheet is detected. The accumulation It is characterized in that detecting the end of an optical sheet.

A second image reading method according to the present invention is characterized in that, in the above-described image reading method of the double-sided reading method, the condensing mirror has a property of transmitting the reflected excitation light reflected by the stimulable phosphor sheet. Then, when the tip of the stimulable phosphor sheet is main-scanned by the excitation light, the reflection excitation light transmitted through the converging mirror among the reflection excitation light reflected by the tip of the stimulable phosphor sheet is detected. The end of the stimulable phosphor sheet is detected.

It is preferable that the condensing mirror has a characteristic of reflecting the stimulated emission light.

Further, in the first and second image reading methods, the stimulable phosphor sheet is subjected to the sub-scanning while a lower surface thereof is supported by a guide plate, and the stimulable phosphor sheet has a lower surface. It is preferable that an opening is provided at a position of the guide plate corresponding to a position where the excitation light is irradiated, and at least the excitation light of the stimulable phosphor sheet is irradiated instead of the opening. The position of the guide plate corresponding to the position to be performed may be colored black.

Further, a first image reading apparatus according to the present invention is for carrying out the first image reading method according to the present invention, and an excitation light is applied to a stimulable phosphor sheet on which a radiation image is stored and recorded. Main scanning means for performing main scanning, sub-scanning means for sub-scanning the stimulable phosphor sheet in a direction substantially perpendicular to the main scanning direction, and brightness obtained from the stimulable phosphor sheet by main scanning of the excitation light. A condensing mirror that reflects stimulated emission light and is disposed in the stimulable phosphor sheet near a location where the excitation light is irradiated; and a stimulable luminescent light obtained from the stimulable phosphor sheet and the stimulable phosphor sheet. An image reading apparatus comprising: reading means for photoelectrically reading stimulated emission light reflected by an optical mirror, wherein the condensing mirror has a property of transmitting reflected excitation light reflected by the stimulable phosphor sheet. I Detecting means for detecting the reflected excitation light transmitted through the condensing mirror is provided on the supporting means for supporting the condensing mirror, and when the leading end of the stimulable phosphor sheet is main-scanned by the excitation light, The reflection excitation light transmitted through the condensing mirror among the reflection excitation light from the front end of the phosphor sheet is detected by the detection means to detect the front end of the stimulable phosphor sheet.

Further, the second image reading apparatus according to the present invention is characterized in that, in the image reading apparatus of the above-mentioned double-side reading system, the light-collecting mirror transmits the reflection excitation light reflected by the stimulable phosphor sheet. A detecting means for detecting the reflected excitation light transmitted through the condensing mirror is provided on a supporting means for supporting the condensing mirror, and when the leading end of the stimulable phosphor sheet is main-scanned by the excitation light, The reflection excitation light transmitted through the converging mirror among the reflection excitation light by the tip of the stimulable phosphor sheet is detected by the detection means to detect the tip of the stimulable phosphor sheet. .

It is preferable that the condensing mirror has a characteristic of reflecting the stimulated emission light.

Further, the first and second image reading apparatuses further include a guide plate for guiding a lower surface of the stimulable phosphor sheet, and the guide plate includes the excitation light of the stimulable phosphor sheet. It is preferable that an opening is provided at a position corresponding to a position where the excitation light is irradiated, instead of the opening at least at a position where the excitation light of the stimulable phosphor sheet is irradiated. The corresponding position may be colored black.

[0016]

According to the image reading method and apparatus of the present invention, the reflection excitation reflected by the tip of the stimulable phosphor sheet which has passed through the condensing mirror for reflecting and condensing the scattered stimulating light is reflected. Since the light is detected, it is not necessary to consider the mounting position of the detecting means for detecting the reflected excitation light, and the apparatus can be simply configured. In particular, in the image reading method and apparatus that performs double-sided focusing, the reading unit is also provided on the back surface of the stimulable phosphor sheet, so it is very difficult to attach the detecting unit. By detecting the reflected excitation light transmitted through the condensing mirror, the detecting means can be attached to the supporting means of the condensing mirror as in the apparatus according to the present invention, and the apparatus can be constructed without any trouble. Can be. Further, since the mounting position of the detecting means can be fixed to the supporting means of the condenser mirror, the leading end of the stimulable phosphor sheet can always be detected stably.

When the lower surface of the stimulable phosphor sheet is guided by the guide plate, an opening is provided at a position of the guide plate corresponding to a portion of the stimulable phosphor sheet irradiated with the excitation light. Until the tip of the stimulable phosphor sheet is sub-scanned at the position where the excitation light is irradiated, the excitation light is not reflected by the guide plate,
The reflected excitation light is not detected by the detecting means.
Thus, the reflected excitation light is detected by the detecting means only when the tip of the stimulable phosphor sheet is irradiated with the excitation light, so that the tip of the stimulable phosphor sheet can be detected more accurately. it can.

Further, in this case, without providing an opening in the guide plate, at least the position of the stimulable phosphor sheet corresponding to the position where the excitation light is irradiated is colored black, so that the excitation light is applied to the guide plate. Even if irradiated, the excitation light is hardly reflected. Therefore, the excitation light is not reflected by the guide plate until the tip of the stimulable phosphor sheet is sub-scanned to the position where the excitation light is irradiated.
The reflected excitation light is no longer detected by the detection means,
Thereby, the reflected excitation light is detected by the detecting means only when the tip of the stimulable phosphor sheet is irradiated with the excitation light, and the tip of the stimulable phosphor sheet can be detected more accurately.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a radiation image photographing apparatus. As shown in FIG. 1, the stimulable phosphor sheet 4 is arranged, the radiation source 3 is driven, and the radiation 2 is emitted, so that the radiation 2 transmitted through the subject 1 is irradiated on the stimulable phosphor sheet 4. Then, the radiation image information of the subject 1 is accumulated and recorded on the stimulable phosphor sheet 4.

Next, from the stimulable phosphor sheet 4, FIG.
The radiation image is read by the image reading apparatus according to the present invention as shown in FIG.

The stimulable phosphor sheet 4 is placed on endless belts 9a and 9b rotated by a motor (not shown). The endless belts 9a and 9b support both sides of the stimulable phosphor sheet 4, and the center of the stimulable phosphor sheet 4 is supported by a center guide 8. Above the sheet 4, a laser light source 10 that emits laser light 11 as excitation light
And a rotary polygon mirror 12 that reflects and deflects the laser light 11 and rotates the motor 4 (not shown) that scans the sheet 4 in the main direction. The laser light in the center guide 8
An opening 8A is formed at a position where 11 is irradiated.
Further, above the position where the laser light 11 is scanned, a light-collecting guide 14a for condensing stimulated emission light emitted by the scanning of the laser light 11 from above is disposed in close proximity, and below the position. A light condensing guide 14b for condensing stimulated emission light from below is disposed perpendicular to the sheet 4. In addition, a light-collecting mirror 7 is disposed near the light-collecting guide 14a to reflect stimulated emission light scattered and emitted from the stimulable phosphor sheet 4 toward the light-collecting guide 14a. . Note that the condenser mirror 7 is supported by the mirror mount 6.
Each of the condensing guides 14a and 14b is provided with a photomultiplier (photomultiplier) 15 for photoelectrically detecting photostimulated light.
a and 15b are connected. This photo multiplier
15a and 15b are connected to logarithmic amplifiers 16a and 16b, and the logarithmic amplifiers 16a and 16b further connect to A / D converters 17a and 17b.
, And each A / D converter 17a, 17b is connected to the storage means 18.

The converging mirror 7 is formed of a dichroic mirror and has a wavelength range of
It transmits light in the wavelength range of 0 nm and is 400
It reflects light in the wavelength range of ~ 500 nm. As shown in FIG. 3, a sensor 5 for detecting light transmitted through the light collecting mirror 7 is embedded in the center of a mirror mount 6 that supports the light collecting mirror 7. As shown in FIG. 2, a passage 6 </ b> A for guiding the light transmitted through the condenser mirror 7 is formed substantially at the center of the mirror mount 6, and the light passing through the passage 6 </ b> A is detected by the sensor 5. Then, the detection output of the sensor 5 is input to the sequence controller 20 of the present apparatus as a start point signal B. Here, the sequence controller 20
Starts detection of photostimulated light by the photomultipliers 15a and 15b based on the start signal B input from the sensor 5.

The stimulable phosphor sheet 4 on which the radiation image of the subject is stored is set on the endless belts 9a and 9b and on the center guide 8. The stimulable phosphor sheet 4 set at the predetermined position is provided with an endless belt 9a,
By 9b, the sheet is conveyed (sub-scan) in the arrow Y direction. on the other hand,
Laser light 11 emitted from a laser light source 10 is reflected and deflected by a rotating polygon mirror 12 driven by a motor (not shown) and rotated at a high speed, enters the sheet 4 and is substantially perpendicular to the sub-scanning direction (arrow Y direction). Main scanning in the direction perpendicular to the paper).

Here, the laser beam 11 is applied to the center guide 8 until the sheet 4 is conveyed to the irradiation position of the laser light 11. Since the opening 8A is formed, the laser beam 11 is not reflected by the center guide 8. When the sheet 4 is conveyed to the irradiation position of the laser light 11, the stimulated emission light 13a, 13b having a light amount corresponding to the radiation image information stored and recorded is emitted from the portion of the sheet 4 irradiated with the laser light 11. (Here, the stimulating light 13a, 13b
Are emitted from above and below the sheet 4, respectively), and the laser beam 11 is reflected by the leading end of the sheet 4. Although the stimulated emission light 13a emitted from the surface of the sheet 4 is scattered, it is reflected by the condensing mirror 7 and condensed on the condensing guide 14a. On the other hand, the laser beam 11 reflected by the sheet 4 passes through the condenser mirror 7 and is detected by the sensor 5 provided on the mirror mount 6. The sensor 5 is a laser beam transmitted through the focusing mirror 7.
When 11 is detected, the start signal B is sent to the sequence controller.
Output to 20. The sequence controller 20 includes the sensor 5
The detection by the photomultipliers 15a and 15b is started based on the starting point signal B input from the.

The stimulated emission light 13a that has entered the light-collecting guide 14a from the incident end face travels through the light-guiding guide 14a after repeated total reflection, exits from the emission end face, is received by the photomultiplier 15a, Stimulated light 13a representing an image
Is converted into an electric signal by the photomultiplier 15a. Similarly, the stimulated emission light 13b is
And is photoelectrically detected by the photomultiplier 15b.

The photo-analog image signal output from the multiplier 15a S _A are input is logarithmically amplified by a logarithmic amplifier 16a to the A / D converter 17a, a storage unit where it is converted into digital image signals S ₁ Entered in 18. Similarly, photomultiplier 15b analog image signals output from the S _B is inputted is logarithmically amplified by a logarithmic amplifier 16b to the A / D converter 17b, a storage where it is converted into a digital image signal S ₂ Input to means 18. Storage means
The digital image signals S ₁ and S ₂ stored in 18 are input to the image processing means 19 and added together. The added image signal Sadd thus obtained is subjected to predetermined image processing, and is used for reproducing a radiation image by a reproducing unit (not shown).

This reproducing means may be a display means such as a CRT or a recording device for performing optical scanning recording on a photosensitive film.

As described above, in the present embodiment, the sensor 5 for detecting the leading end of the stimulable phosphor sheet 4 is provided on the mirror mount 6 supporting the light collecting mirror 7.
It is not necessary to consider the mounting position of the sensor 5 for detecting the leading end of the sheet 4, and the apparatus can be simply configured. In particular, in the image reading apparatus that performs double-sided focusing as in the present embodiment, since the focusing guide 14b is also provided on the back surface of the stimulable phosphor sheet 4, it is very difficult to attach the sensor 5. However, by attaching the sensor 5 to the mirror mount 6 of the condenser mirror 7 as in the present embodiment, the device can be configured without any trouble. Further, since the mounting position of the sensor 5 is fixed to the mirror mount 6, the leading end of the stimulable phosphor sheet 4 can be stably detected.

Further, in the present embodiment, the opening 8A is provided at a position corresponding to the position where the laser beam 11 is irradiated on the center guide 8 for guiding the lower surface of the stimulable phosphor sheet 4.
Is provided, the tip of the stimulable phosphor sheet 4 is
Since the laser beam 11 is not reflected by the center guide 8 even if the laser beam 11 is not located at the position where the
Then, the reflected laser beam 11 is not detected. As a result, the reflected laser light 11 is detected by the sensor 5 only when the laser light 11 is irradiated to the tip of the stimulable phosphor sheet 4, so that the tip of the stimulable phosphor sheet 4 can be detected more accurately. Can be.

In the above-described embodiment, the image reading apparatus that performs double-side reading has been described. However, as shown in FIG. 4, a radiation image reading apparatus that reads a radiation image from only one side of the stimulable phosphor sheet 4 is used. The present invention can be applied to the radiation image reading apparatus shown in FIG. In FIG. 4, the same components as those in FIG. 2 are assigned the same reference numerals as those in FIG. 2 except for “a”, and detailed descriptions thereof are omitted.

Further, in the above embodiment, the opening 8A is provided at the position of the center guide 8 where the laser beam 11 is irradiated, but the surface of the center guide 8 is colored black without providing the opening 8A. You may make it. As a result, even if the center guide 8 is irradiated with the laser beam 11, the laser beam 11 is hardly reflected, so that the stimulable phosphor sheet 4
The laser beam 11 is not reflected by the center guide 8 until the tip of the laser beam 11 is conveyed to the location where the laser beam 11 is irradiated. As a result, the reflected laser light 11 is detected by the sensor 5 only when the laser light 11 is irradiated to the tip of the stimulable phosphor sheet 4, so that the tip of the stimulable phosphor sheet 4 can be detected more accurately. Can be done. Note that the portion colored black may be the entire surface of the center guide 8 or only the portion irradiated with the laser beam 11.

Further, in the above embodiment, the sensor 5 is provided substantially at the center of the mirror mount 6 as shown in FIG. 3, but at a position where the reflected laser beam 11 transmitted through the condenser mirror 7 can be detected. If so, it may be provided at any position. Further, the sensor 5 is embedded in the mirror mount 6, but is not limited to this.
You may make it attach to the surface of.

[Brief description of the drawings]

FIG. 1 is a diagram showing a radiographic image capturing apparatus;

FIG. 2 is a diagram illustrating an image reading apparatus according to an embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a mirror mount.

FIG. 4 is a diagram showing an image reading apparatus according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Subject 2 Radiation 3 Radiation source 4 Storage phosphor sheet 5 Sensor 6 Mirror mount 7 Condensing mirror 8 Center guide 8A Opening 10 Laser light source 11 Laser light 12 Rotating polygon mirror 13a, 13b Stimulated emission light 14a, 14b Condensing Guides 15a, 15b Photomultipliers 16a, 16b Logarithmic amplifiers 17a, 17b A / D converter 18 Storage means 19 Image processing means 20 Sequence controller

Claims (10)

[Claims] An excitation light is main-scanned on a stimulable phosphor sheet on which a radiation image is accumulated and recorded, and the stimulable phosphor sheet is sub-scanned in a direction substantially perpendicular to the main scanning direction to convert the radiation image. The stimulable phosphor sheet is converted into stimulable luminescent light, and the stimulable luminescent light obtained from the stimulable phosphor sheet is reflected by a condensing mirror disposed near a location of the stimulable phosphor sheet irradiated with the excitation light. In the image reading method for condensing and reading photoelectrically, the condensing mirror has a property of transmitting reflected excitation light reflected by the stimulable phosphor sheet, and the tip of the stimulable phosphor sheet is excited by the excitation light. When the main scanning is performed by the light, the reflection excitation light transmitted through the converging mirror among the reflection excitation light reflected by the tip of the stimulable phosphor sheet is detected to detect the tip of the stimulable phosphor sheet. Image Preparative Method. 2. The radiation image is scanned by main scanning the stimulable phosphor sheet on which the radiation image is accumulated and recorded, and sub-scanning the stimulable phosphor sheet in a direction substantially perpendicular to the main scanning direction. The stimulable phosphor sheet is converted into stimulable luminescence light, and the stimulable luminescence light obtained from the surface of the stimulable phosphor sheet is disposed in the vicinity of a position where the excitation light is irradiated on the surface side of the stimulable phosphor sheet. An image reading method wherein the light is reflected and collected by the condensing mirror and read photoelectrically, and the photostimulable emission light obtained from the back surface of the stimulable phosphor sheet is read photoelectrically. Having the property of transmitting the reflected excitation light reflected by the body sheet; and when the tip of the stimulable phosphor sheet is main-scanned by the excitation light, the reflected excitation light is reflected by the tip of the stimulable phosphor sheet. The collection Image reading method characterized by detecting the reflected excitation light transmitted through the mirror to detect the leading end of the stimulable phosphor sheet. 3. The image reading method according to claim 1, wherein the condenser mirror further has a characteristic of reflecting the stimulated emission light. 4. The stimulable phosphor sheet has its lower surface supported by a guide plate and is subjected to the sub-scanning, and the guide plate corresponding to a portion of the stimulable phosphor sheet irradiated with the excitation light. 4. The image reading method according to claim 1, wherein an opening is provided at the position of (1). 5. The stimulable phosphor sheet has its lower surface supported by a guide plate and is subjected to the sub-scanning, and at least the guide corresponding to a portion of the stimulable phosphor sheet irradiated with the excitation light. 4. The image reading method according to claim 1, wherein the position of the plate is colored black. 6. A main scanning means for main-scanning an excitation light on a stimulable phosphor sheet on which a radiation image is stored and recorded, and a sub-scan for sub-scanning the stimulable phosphor sheet in a direction substantially perpendicular to the main scanning direction. Means for collecting photostimulated light obtained from the stimulable phosphor sheet by main scanning of the stimulable light, the stimulable phosphor sheet reflecting a stimulable light emitted from the stimulable phosphor sheet; An image reading apparatus comprising: a light mirror; and a reading unit that photoelectrically reads stimulated emission light obtained from the stimulable phosphor sheet and stimulated emission light reflected by the condensing mirror. Has a characteristic of transmitting the reflection excitation light reflected by the stimulable phosphor sheet, and a detection means for detecting the reflection excitation light transmitted through the light collection mirror is provided on a support means for supporting the light collection mirror, The accumulation When the leading end of the stackable phosphor sheet is main-scanned by the excitation light, the reflected excitation light transmitted through the converging mirror among the reflected excitation light by the leading end of the stimulable phosphor sheet is detected by the detection unit. An image reading device for detecting a tip of the stimulable phosphor sheet. 7. Main scanning means for main scanning excitation light on a stimulable phosphor sheet on which a radiation image is stored and recorded, and sub-scanning for sub-scanning the stimulable phosphor sheet in a direction substantially perpendicular to the main scanning direction. Means for reflecting stimulated emission light obtained from the surface of the stimulable phosphor sheet by the main scanning of the stimulable phosphor sheet, the stimulable phosphor sheet being disposed in the vicinity of a portion of the stimulable phosphor sheet irradiated with the excitation light. A condenser mirror, first reading means for photoelectrically reading stimulated emission light obtained from the surface of the stimulable phosphor sheet and stimulated emission light reflected by the condenser mirror, and the stimulable phosphor An image reading apparatus comprising: a second reading unit that photoelectrically reads stimulated emission light obtained from a back surface of a sheet; wherein the light-collecting mirror transmits reflected excitation light reflected by the stimulable phosphor sheet. Has characteristics Detecting means for detecting reflected excitation light transmitted through the condensing mirror is provided on supporting means for supporting the condensing mirror, and when the leading end of the stimulable phosphor sheet is main-scanned by the excitation light, An image reading apparatus, wherein the detecting means detects the reflected excitation light transmitted through the converging mirror among the reflected excitation light from the front end of the phosphor sheet to detect the front end of the stimulable phosphor sheet. 8. The image reading apparatus according to claim 6, wherein the light collecting mirror further has a characteristic of reflecting the stimulated emission light. 9. A stimulable phosphor sheet further comprising a guide plate for guiding a lower surface of the stimulable phosphor sheet, wherein the guide plate has an opening at a position corresponding to a location of the stimulable phosphor sheet irradiated with the excitation light. The image reading apparatus according to any one of claims 6 to 8, further comprising: 10. A guide plate for guiding a lower surface of the stimulable phosphor sheet, wherein at least a position of the stimulable phosphor sheet corresponding to a portion of the stimulable phosphor sheet irradiated with the excitation light is black. 9. The image reading apparatus according to claim 6, wherein the image reading apparatus is colored.