JPS6335067A - Light beam scanning mechanism - Google Patents

Abstract

PURPOSE:To exactly carry a body to be scanned, in the sub-scanning direction by a simple constitution, by constituting a pair of rollers for inserting/holding and carrying various bodies to be scanned whose sizes are different by putting them in order in one end side, so that a nip force of one end side becomes larger than a nip force of the other end side. CONSTITUTION:The respective accumulative phosphor sheets A whose sizes are different are guided by a doubling plate 71 as shown by a one point chain line and inserted and held by a pair of the first rollers 44 so that the respective one side faces are put in order in the respective shaft 50b, 52b sides of a pair of the first rollers 44. Accordingly, in order that a pressure force of a pressure member 64b engaged to the shaft 52b becomes larger than a pressure force to a shaft 52a by a pressure member 64a, a coil spring 73 whose spring constant is larger than that of a coil spring 72 is used. Also, even if the spring constants are the same, when length of the coil spring 73 is selected so as to be longer than length of the coil spring 72, the pressure force to the shaft 52b can be made larger substantially than the pressure force to the shaft 52a.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a light beam scanning mechanism, and more particularly, the present invention relates to a light beam scanning mechanism, and more specifically, for example, scanning and reading by irradiating an object to be scanned, such as a stimulable phosphor sheet on which a radiation image is accumulated and recorded, with excitation light. The present invention relates to a light beam scanning mechanism configured to accurately transport objects to be scanned of various sizes in the sub-scanning direction by aligning them on one end side and sandwiching them between a pair of rollers.

Recently, a radiation image recording and reproducing system that obtains a radiation image of a subject using a stimulable phosphor (stimulable phosphor) has been attracting attention. Here, the storage fluorophore refers to radiation (X-rays, α
When irradiated with rays, β rays, γ rays, electron beams, ultraviolet rays, etc., a part of this radiation energy is accumulated, and later when excitation light such as visible light is irradiated, stimulated luminescence light is produced according to the accumulated energy. Refers to the phosphor that is produced.

The radiation image recording and reproducing system described above utilizes this stimulable phosphor, and the radiation image information of a subject such as a human body is stored on a sheet having a layer made of a stimulable phosphor (hereinafter referred to as a ``stimulable phosphor sheet''). (or simply referred to as a "sheet"), this stimulable phosphor sheet is scanned with excitation light such as a laser beam to generate stimulated luminescent light, and the stimulated luminescent light is read photoelectrically. An electrical signal is obtained, and based on this electrical signal, a radiation image of the subject is output as a visible image to a recording material such as a photographic light-sensitive material or a display device such as a CRT.

Therefore, in such a radiographic image recording and reproducing system, an image reading device that reads a radiographic image from a stimulable phosphor sheet on which the radiographic image is stored and recorded specifically reads the radiographic image by the following method. reading.

That is, a stimulable phosphor sheet is scanned two-dimensionally with a light beam such as a laser beam, and the stimulated luminescent light emitted by this is detected in time series with a photodetector such as a photomultiplier to create an image. get information. The two-dimensional scanning of the light beam usually involves performing main scanning by deflecting and irradiating the light beam onto the phosphor sheet in a -dimensional manner, and moving the sheet in a direction substantially orthogonal to the main scanning direction. This is accomplished by mechanically conveying the image using a belt conveyor or the like, thereby performing sub-scanning.

Next, the image information obtained as described above is sent to an image recording device. The image recording device irradiates a photographic light-sensitive material, which is a recording material, with a laser beam modulated based on the image information obtained from a stimulable phosphor sheet to record a predetermined image on the photographic light-sensitive material. It is composed of

After the photographic light-sensitive material on which the new image has been recorded is subjected to development processing, it is stored at a predetermined location and used for medical diagnosis, etc., as necessary.

Incidentally, the stimulable phosphor sheets are used in various sizes depending on the subject. That is,
The stimulable phosphor sheet only needs to have a size necessary for storing and recording a desired radiation image. For example, if the subject is a relatively small object or part, the stimulable phosphor sheet should have a size corresponding to the subject. It is extremely economical to use a small stimulable phosphor sheet. Therefore, the image reading device is loaded with stimulable phosphor sheets of various sizes,
A scanning reading operation is performed on each stimulable phosphor sheet.

In this case, in the image reading device, when conveying stimulable phosphor sheets of different sizes to the reading section, for example, a conveying belt is provided to be inclined toward the reading section, and the conveying belt is tilted toward the reading section. The respective stimulable phosphor sheets are conveyed via a belt so as to be aligned with one end of the reading section. For this reason, when the stimulable phosphor sheet is conveyed in the sub-scanning direction by the pair of conveying rollers, especially when the stimulable phosphor sheet is narrow in the main scanning direction, one end of the pair of rollers You will pass by the side.

However, in this case, both ends of one of the rollers constituting the pair of rollers are pressed toward the other roller by elastic bodies having the same strength.

Therefore, especially when a relatively thick sheet such as a stimulable phosphor sheet is held between one end of the pair of rollers,
Due to the elastic force of the elastic body at the other end of the pair of rollers, the one roller tends to tilt significantly. Therefore, only a portion of the stimulable phosphor sheet is held between the pair of rollers, and there is a possibility that the stimulable phosphor sheet is not conveyed accurately in the sub-scanning direction. As a result, in the case of a stimulable phosphor sheet that is not suitably conveyed in the sub-scanning direction, it is pointed out that there is a disadvantage that the image scanning and reading operation of the stimulable phosphor sheet becomes inaccurate.

The present invention has been made to overcome the above-mentioned disadvantages, and the object to be scanned, such as the stimulable phosphor sheet 1-, is scanned by being held and conveyed so as to be aligned with one end of a pair of rollers. In addition, by selecting the nip force on the one end side of the pair of rollers to be larger than the nip force on the other end side,
Even if the object to be scanned is relatively narrow, the eccentric movement of the rollers that tends to occur when the object is sandwiched between the pair of rollers can be prevented by the difference in nip force at each end. It is an object of the present invention to provide a light beam scanning mechanism that has an extremely hourly configuration and can accurately convey objects to be scanned of various sizes in the sub-scanning direction to suitably perform scanning reading, scanning recording, etc. purpose.

In order to achieve the above object, the present invention performs sub-scanning by transporting a sheet-shaped object to be scanned in one direction, and irradiates the main scanning object with a light beam deflected in a direction substantially perpendicular to the one direction. A light beam scanning mechanism that scans a pair of rollers that nip and convey various scanned objects of different sizes so that they are aligned on one end, and the nip force on one end is greater than the nip force on the other end. It is characterized by being configured so that

Next, preferred embodiments of the light beam scanning mechanism according to the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 1, reference numeral 10 indicates an image reading device incorporating a light beam scanning mechanism according to the present invention. A supply magazine 14 is removably attached to the chamber 12 in the image reading device 10, and stimulable phosphor sheets A on which radiation images have been stored and recorded are stored in a stacked manner in the supply magazine 14. ing. A sheet feeding mechanism including a suction cup 16 is provided in the chamber 12 adjacent to the supply magazine 14, and below the suction cup 16 is an endless first conveyor belt for conveying the stimulable phosphor sheet A. An eye 8 is provided.

The first conveyor belt 18 extends vertically downward and is bent at an internal corner of the image reading device 10 so as to be oriented in the horizontal direction. A plurality of rollers 20a are arranged in the vertical direction so as to be in contact with each other.
20d are provided. Furthermore, a large-diameter roller 22 is disposed at the lower bent portion of the first conveyance heald 18 .

Therefore, the light beam scanning mechanism 24 according to this embodiment is provided at the center of the lower side of the image reading device 10.

In this case, the light beam scanning mechanism 24 is connected to the image reading section 26.
and a first conveyor belt) 18 located below the reading section 26.
Sheet body conveying section 2 provided at a slight distance from the terminal end of
It basically consists of 8.

The reading section 26 includes a laser light source 30, and a mirror 34 for scanning the laser light 32 on the sheet, a galvanometer mirror 36, and a condensing reflecting mirror 38 are provided on the laser light output side of the laser light tX30. There is. Further, a light guide 40 is disposed along the main scanning line at the scanning position of the laser beam 32 on the sheet, and a photomultiplier 42 is mounted above the light guide 40.

On the other hand, the sheet conveying section 28 includes a first roller pair 44 and a second roller pair 46, and the roller pair 44, 46 includes a first roller pair 44 and a second roller pair 46.
Guide members 48a and 48b for holding the stimulable phosphor sheet A being conveyed are arranged between them. Said first
The roller pair 44 includes a rotationally driven roller 50 and a roller 52 that rotates in sliding contact with the roller 50, while the second roller pair 46 includes a rotationally driven roller 54 and a roller 56 disposed above the roller 50. Consisting of In this case, the first roller pair 44 is configured as shown in FIGS. 2 and 3, and the second roller pair 46 is also configured similarly to the first roller pair 44, so the second roller pair 44 is configured as shown in FIGS. A detailed explanation of 46 will be omitted.

That is, the shafts 5Qa and 50b of the rollers 50 constituting the first roller pair 44 are rotatably supported by support plates 58a and 58b that are provided upright within the image reading device 10. The roller 50 is engaged with, for example, a roller 54 constituting the second roller pair 46 via a belt or the like, and rotates under the driving action of a rotational drive source (not shown) that is engaged with the roller 54. It is configured like this. Moreover, the shafts 52a, 52 of the roller 52
b denotes an oblong hole 60 formed in the support plates 58a and 58b, respectively.
a, 60b, in which case a gap 62 is defined between the roller 52 and the roller 50 when the roller 52 is at its lowest end (see FIG. 3). The gap 62 is selected to be slightly smaller than the thickness of the stimulable phosphor sheet A held between the roller pair 44, for example, when the thickness of the stimulable phosphor sheet A is approximately 0.5 mm to If it is 0.7 mm, it is preferable to select the gap 62 to be approximately 0.2+Im to 0.4 fins. Furthermore, the shaft 52 of the roller 52
Pressing members 64a and 64b are engaged with a and 52b.

The pressing members 64a, 64b have a U-shape, and the upper portions 66a, 66b of each are bulged in the horizontal direction.
Shafts 52a, 52b are provided on the lower surfaces of the upper portions 66a, 66b.
Grooves 68a and 68b are formed for fitting. The lower portions 70a, 70b of the pressing members 64a, 64b are bulged in the horizontal direction like the upper portions 66a, 66b, and coil springs 72, 73 are attached to the respective lower portions 70a, 70b.
One end of the is engaged. Said coil spring 72.73
Although the other end portions are not shown, they are fixed within the image reading device 10, and the pressing members 64a, 64b are pressed vertically downward by the elastic force of the respective coil springs 72, 73.

In this case, each stimulable phosphor sheet A of different size
is guided by the contact plate 71 indicated by the dashed line in FIG.
, 52b side with one side of each of the first
It is held between a pair of rollers 44. Therefore, in order to make the pressing force of the pressing member 64b that engages with the shaft 52b larger than the pressing force of the pressing member 64a against the shaft 52a, the coil spring 73 has a larger spring constant than the coil spring 72. Further, even if the spring constants are the same, if the length of the coil spring 73 is selected to be longer than the length of the coil spring 72, the length of the coil spring 72 is substantially the same as that of the shaft 52.
The pressing force on the shaft 52a can be made larger than the pressing force on the shaft 52a.

Next, the roller 52 is inserted into the oblong hole 60a.
, 60b engage roller displacement means 74 for vertical movement. An electromagnetic actuator constituting the roller displacement means 74, for example, a rotary solenoid 76, is mounted on the support plate 58a, and one end of a first arm 78 is fixed to a rotational drive shaft 76a extending from the rotary solenoid 76. be done. The other end of the first arm 78 engages with a bearing 82 provided at one end of the second arm 80, and in this case, the second arm 80 has both ends attached to respective support plates 58a, A rotating shaft 86 rotatably supported by 58b is fitted and engaged. Also,
A locking portion 80a is provided at the other end of the second arm 80 via a stepped portion.
is formed, and the shaft 52a of the roller 52 is attached to this locking portion 80a.
Place. On the other hand, an arm 88 is similarly secured to the support plate 58b side of the rotating shaft 86, and a locking portion 88a is formed at the end of the arm 88 via a stepped portion.

An endless second conveyance belt 92 is provided close to the second roller pair 46 of the light beam scanning mechanism 24 configured in this manner. The second conveyor belt 92 once extends in the horizontal direction, and in FIG. 1, it extends largely vertically upward, bends in the horizontal direction at its terminal end, and has a tip directed slightly downward. put. In addition,
A large-diameter roller 94 is disposed at the lower bent portion of the second conveyor belt 92 . Further, a plurality of rollers 96a to 96e are provided in a vertically extending portion of the second conveyor belt 92.
A large diameter roller 98 and rollers 100a and 100b are provided at the upper bent portion of the second conveyor belt 92 to convey the stimulable phosphor sheet A vertically downward. ing.

A receive magazine 102 for storing the stimulable phosphor sheet A is provided adjacent to the roller 100b.

Furthermore, within the chamber 12, for example, a conveyor belt 92 is provided.
An erasing unit 10 is provided between rollers 96b and 96c provided in
Place 4. Note that a plurality of erasing light sources (not shown) are provided inside the erasing section 104.

The image reading device incorporating the light beam scanning mechanism of this embodiment is basically constructed as described above, and its operation and effects will be explained next.

First, the supply magazine 14 is installed in the chamber 12 of the image reading device 10 . In this case, the supply magazine 1
A plurality of stimulable phosphor sheets A on which radiation images of a subject such as a human body are stored and recorded are stacked and housed in the storage unit 4 .

Therefore, the stimulable phosphor sheets A are taken out one by one from the supply magazine 14 under the action of a single sheet mechanism including a suction cup 16, and a first conveyor belt 18 provided below the suction cup 16 and a plurality of The sheet is conveyed to the sheet conveyance section 28 side via the rollers 20a to 20d and the roller 22.

Here, the roller displacement means 74 is driven. That is,
Rotating drive shaft 76 under the driving action of rotary solenoid 76
When a rotates in the direction of arrow B, the first arm 78 that is engaged with the rotation drive shaft 76a similarly swings in the direction of arrow B, and presses the bearing 82 that is engaged with one end thereof in the direction of arrow B. . The bearing 82 is attached to the second arm 80, and when the bearing 82 is pressed in the direction of arrow B, the second arm 80 swings integrally with the rotating shaft 86, and the second arm 80 swings integrally with the rotating shaft 86. The locking portion 80a swings in the direction of arrow C. At this time, the other arm 88 is engaged with the rotating shaft 86, and a locking portion 88a formed at the tip of this arm 88 similarly swings in the direction of arrow C. Therefore, the shafts 52a, 52b that engage with the respective locking portions 80a, 88a are guided into the oblong holes 60a, 6'Ob against the tensile force of the coil springs 72, 73 that engage the pressing members 54a, 64b. and is displaced vertically upward. As a result, the rollers 52 with their respective shafts 52a, 52b are separated from the rollers 50 by at least the thickness of the stimulable phosphor sheet A.

Therefore, when the stimulable phosphor sheet A enters between the rollers 50 and 52, the rotary solenoid 76 constituting the roller displacement means 74 is driven again. In this case, under the action of the rotary solenoid 76, the rotary drive shaft 76a is rotated in the direction of the arrow, contrary to the above, and the rotary drive shaft 76a
The first arm 78 that engages similarly swings in the direction of the arrow. Therefore, the holding action of the shafts 52a, 52b by the second arm 80 and the arm 88 is released, and the shafts 52a,
52b is displaced vertically downward via pressing members 54a and 64b that engage coil springs 72 and 73, and the stimulable phosphor sheet 1-A is held between the first pair of rollers 44. Here, the gap 62 between the rollers 50 and 52 is selected in advance to be smaller than the thickness of the stimulable phosphor sheet A, and when the stimulable phosphor sheet A is sandwiched between the rollers 50 and 52, the roller A pressing member 5 is attached to the shafts 52a and 52b of 52.
The tensile force of the coil spring 72.73 acts directly through 4a, 64b.

As a result, the stimulable phosphor sheet A is suitably held between the first pair of rollers 44 by the tensile force of the coil springs 72 and 73.

When the roller 54 is rotated under the driving action of a rotational drive source (not shown) connected to the roller 54 constituting the second roller pair 46, the roller 50 engaged with the roller 54 via a heald or the like is rotated. and stimulable phosphor sheet A
is held between the first roller pair 44 and the second roller pair 46
transported to the side.

In this way, the stimulable phosphor sheet A is transported in the sub-scanning direction (direction of arrow E) via the sheet transport section 28, and the reading section 26 is driven.

That is, the laser light 32 derived from the laser light source 30
is reflected by a mirror 34 to reach a galvanometer mirror 36, and the laser beam 32 is scanned on the sea 1-A while the galvanometer mirror 36 swings. Thereby, the stimulated luminescence light emitted from the sheet A is incident directly or reflected by the reflection mirror 38 into the light guide 40, and is converted into an electrical signal by the photomultiplier 42 and used, for example, in an image recording device. send.

At this time, the leading end side of the stimulable phosphor sheet A, which is conveyed in the direction of arrow E via the first roller pair 44, is transferred to the second roller pair 44.
6. Here, similarly to the first roller pair 44 described above, the roller 56 constituting the second roller pair 46 is separated from the roller 54 via a roller displacement means (not shown).

Further, the stimulable phosphor sheet A is attached to the respective rollers 54 and 5.
6, the roller 56 is displaced downward, and the second roller pair 46 removes the stimulable phosphor seal l.
-Grasp A. Then, while the stimulable phosphor sheet 1-A is conveyed in the direction of arrow E by the second roller pair 46 and the first roller pair 44 under the driving action of a rotational drive source (not shown) connected to the roller 54, the reading unit Scanning and reading of the stimulable phosphor sheet A is continued under the driving action of 26. Therefore, the stimulable phosphor sheet A that is being scanned can enter the second roller pair 46 very smoothly without causing any impact, and the scanning and reading operation can be performed with high precision. becomes.

Further, as the stimulable phosphor sheet 1-A is conveyed in the direction of arrow E, the rear end side of the stimulable phosphor sheet 1-A is
It attempts to separate from the roller pair 44. In this case, by driving the roller displacement means 74 to displace the roller 52 vertically upward in the same manner as described above, the first roller pair 4
It is possible to avoid shocks that are likely to occur when the end of the stimulable phosphor sheet A separates from the stimulable phosphor sheet A, and to perform the scanning reading operation by the reading section 26 in a suitable manner.

Therefore, the stimulable phosphor sheet 1-A is two-dimensionally scanned by the laser beam 32, and the stimulable phosphor sheet A is conveyed in the direction of arrow E via the sheet conveying section 28. The image signal is then passed through the reading section 26 and all of its image signals are read.

Then, the stimulable phosphor sheet) A is the 21st! The conveying belt 92) reaches the erasing section 104 via the roller 94 and rollers 96a and 96b. In the erasing section 104, a plurality of erasing light sources (not shown) are turned on, so that the irradiated light completely erases the radiation image remaining on the stimulable phosphor sheet A. The stimulable phosphor sheet A from which the radiation image has been erased is transferred to the second conveyor belt 92) rollers 96c to 96.
It is conveyed to the upper part of the image reading device 10 via the roller 98 and the rollers 100a and 100b, and is stored in the receive magazine 102 with its traveling direction being deviated.

In this case, there is a supply magazine 1 in the image reading device 10.
4 through various different sizes of stimulable phosphor sheets A
is loaded, and each of the stimulable phosphor sheets A is scanned and read by the light beam scanning mechanism 24.

At this time, the stimulable phosphor sheet A is conveyed to the sheet body 1 general feeding section 28 (one side of the stimulable phosphor sheet A is guided by the backing plate 71 and the rollers 50 and 52 constituting the first roller pair 44 Therefore, in the relatively large stimulable phosphor sheath 1-A shown by the two-dot chain line in FIG. versus 4
It will be transported to the 6th side.

However, in FIG. 2, the stimulable phosphor sheet A indicated by the solid line
In the case of a roller having a considerably small size such as the one shown in FIG.
0.52 toward the respective axes 50b and 52b.

Therefore, as shown in FIG. 3, there is a relatively long gap 62 between the rollers 50 and 52 on the respective shafts 50a and 52a.
is defined, and the roller 52 attempts to tilt using the end of the stimulable phosphor sheet 1-A as a fulcrum via a pressing member 64a that engages with a coil spring 72 (as shown by the dashed line in FIG. 3). reference).

However, in this embodiment, in this case, the pressing member 64
The coil spring 73 that engages b has a larger spring constant than the coil spring 72 that engages the pressing member 64a. Therefore, even when a relatively narrow stimulable phosphor sheet (A) is conveyed while being held between one end of the pair of rollers 44 as shown in FIG. It will not tilt due to the force of the spring. As a result, the narrow stimulable phosphor sheet A is held between the respective rollers 50 and 52 and is accurately conveyed in the direction of arrow E (sub-scanning direction).

In this way, the stimulable phosphor sheets A of various sizes can be transferred to the sheet conveying section 2 without being affected by their respective dimensions.
8 can be suitably conveyed in the sub-scanning direction under the driving action of 8, and the scanning/reading operation by the reading section 26 can always be performed with high precision. In the embodiment described above, the grip of the stimulable phosphor sheet A by the first roller pair 44 is released when the sheet A leaves the roller pair 44, but the second roller pair 46 grips the stimulable phosphor sheet A. When the leading end of the sheet A is gripped, the grip of the sheet A by the first pair of rollers 44 may be released, and subsequent sub-scanning conveyance may be performed only by the second pair of rollers 46.

As described above, according to the present invention, an object to be scanned, such as a stimulable phosphor sheet, is held between a pair of rollers and conveyed in the sub-scanning direction, and a relatively narrow object to be scanned is also held between the pair of rollers. The nip force on one end side is selected to be thicker than the nip force on the other end side.For this reason, for example, when a relatively thick object to be scanned, such as a stimulable phosphor sheet, is When the object to be scanned is nipped at one end side, the nip force at the one end side that holds the object to be scanned is greater than the nip force at the other end side defining a gap, thereby preventing the tilting operation of the roller. I can do it.

As a result, objects to be scanned having various sizes can be held between a pair of rollers and conveyed accurately in the sub-scanning direction, resulting in the effect that scanning reading or scanning recording work can be performed with high precision. can get. Furthermore, there is an advantage that the light beam scanning mechanism can be manufactured economically due to its simple configuration.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments.
Of course, various improvements and changes in design are possible without departing from the gist of the invention.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of an image reading device incorporating a light beam scanning mechanism according to the present invention, FIG. 2 is a schematic perspective view of main parts of a light beam scanning mechanism according to the present invention, and FIG. FIG. 3 is a schematic side view of main parts of the beam scanning mechanism. 10... Image reading device 14... Supply magazine 24... Light beam scanning mechanism 26... Reading section 2
8... Sheet body conveyance section 30... Laser light source 44
．． 46... Roller pair 50.52.54.56... Rollers 64a, 64b... Pressing member 72.73... Coil spring 74... Roller displacement means 76... Rotary solenoid 78.80... ... Arm 86 ... Rotating shaft 88
...Arm 92...Transportation heald 102
...Receive magazine 104...Elimination section procedure amendment d (voluntary) October 8, 1986

Claims (7)

[Claims] (1) A light beam scanning mechanism that performs sub-scanning by transporting a sheet-shaped object to be scanned in one direction, and performs main scanning by irradiating a light beam deflected in a direction substantially perpendicular to the one direction. A pair of rollers that nip and convey various scanned objects of different sizes so that they are aligned on one end side are configured so that the nip force on the one end side is greater than the nip force on the other end side. Light beam scanning mechanism. (2) In the mechanism set forth in claim 1, the pair of rollers includes a first roller that engages with a rotational drive source and rotates, and a pressing member that engages the elastic body at both ends. and a second roller that is pressed toward the first roller side, and a second roller that engages with one end of the second roller that clamps the objects to be scanned so that one side of each scanned object of different size is aligned. 1
The elastic body is selected to have a larger tensile force than the second elastic body that engages with the other end of the second roller, and when the object to be scanned is held between one end of the pair of rollers, The tensile force of the first elastic body is applied to the second elastic body against the tensile force of the second elastic body.
A light beam scanning mechanism that prevents the roller from tilting. (3) In the mechanism recited in claim 2, the second
The first elastic body that engages with one end of the roller is made of a coil spring, and this first coil spring has a larger spring constant than the coil spring that is made of a second elastic body that engages with the other end of the second roller. A light beam scanning mechanism comprising: (4) In the mechanism recited in claim 2, the second
The coil spring that is the first elastic body that engages with one end of the roller has the same spring constant as the coil spring that is the second elastic body that engages with the other end of the second roller. A light beam scanning mechanism in which the length of the first coil spring is selected to be longer than the length of the second coil spring. (5) In the mechanism according to any one of claims 2 to 4, the second roller is provided with a roller displacement means, and under the action of the roller displacement means, the second roller is pulled by an elastic body. A light beam scanning mechanism configured to move the light beam away from the first roller against force. (6) A light beam scanning mechanism according to any one of claims 1 to 5, in which the object to be scanned is a stimulable phosphor sheet. (7) A light beam scanning mechanism according to any one of claims 1 to 5, in which the object to be scanned is made of a photographic light-sensitive material.