JPH0545108B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a light beam scanning mechanism, and more specifically, for example, when scanning and reading a stimulable phosphor sheet on which a radiographic image is stored and recorded by irradiating excitation light with it, or when scanning a photographic image. When a photosensitive material is irradiated with a light beam to scan and record an image on the photosensitive material, a pair of rollers arranged to convey a sheet-like object to be scanned are substantially mutually conveyed during the conveyance. The light beam scanning system is configured such that the rollers are brought into pressure contact with the body, while at the time of non-transportation they are separated from each other with a predetermined clearance to avoid deformation of the rollers themselves, thereby constantly conveying the conveyed body with high precision. Regarding the mechanism.

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, storage fluorophores are radiation (X-rays, α-rays, β-rays, γ-rays, electron beams,
A phosphor that accumulates a portion of this radiation energy when irradiated with ultraviolet rays (such as ultraviolet rays), and then produces stimulated luminescent light in response to the accumulated energy when it is later irradiated with excitation light such as visible light.

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. It's reading.

That is, a stimulable phosphor sheet is scanned two-dimensionally with a light beam such as a laser beam, and the stimulated luminescence light emitted thereby is detected in time series with a photodetector such as a photomultiplier. to obtain image information. The two-dimensional scanning of the light beam is usually carried out by mechanically conveying the stimulable phosphor sheet in one direction with a pair of conveying rollers, etc., and at the same time performing a sub-scanning of the stimulable phosphor sheet one-dimensionally. This is achieved by performing main scanning by irradiating a light beam that is deflected in a direction perpendicular to the transport direction.

Next, when the image information obtained as described above is to be output to a photographic material, it is sent to an image recording device. The image recording device irradiates a photographic light-sensitive material as a recording material with laser light modulated based on image information obtained from a stimulable phosphor sheet,
It is configured to expose and record a predetermined image on the photographic material. 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, in the image reading device and the image recording device, the object to be scanned, such as a stimulable phosphor sheet, must be conveyed smoothly in the sub-scanning direction during scanning reading or scanning recording. This is to read or record accurate image information. In order to achieve this objective, it is conceivable to employ nip rollers that rotate while being in pressure contact with each other as a mechanism for conveying the object to be scanned. However, if the rollers are in constant contact with each other under a predetermined pressure, the object to be scanned will receive an impact when it comes between the pair of conveying rollers, and the light beam on the object will be affected. becomes misaligned. As a result, in the case of objects to be scanned that are not smoothly transported in the sub-scanning direction, scanning reading or scanning recording cannot be performed accurately. When trying to perform a medical diagnosis using a medical device, there is a concern that misdiagnosis may occur.

Therefore, in order to reduce the impact that is likely to occur when the object to be scanned enters between the pair of conveying rollers during scanning, and to accurately scan and record the object to be scanned, the applicant has devised a new method. We are also making a number of prototypes. For example, one roller constituting a roller pair is separated from the other roller through the elastic force of an elastic body, and when a scanned object enters between this pair of rollers, the One example is a light beam scanning mechanism configured to nip and convey the object to be scanned in the sub-scanning direction by pressing one roller against the other roller.

By the way, since the roller pair slides on and conveys the object to be scanned, each of the rollers constituting the roller pair is made of a relatively soft material so as not to cause scratches or the like on the surface of the object to be scanned. It is made of material. For example, if the object to be scanned is a stimulable phosphor sheet, each roller is made of polyurethane rubber or the like to achieve accurate scanning and reading without causing scratches on the sheet.
In addition, in order for the pair of rollers to accurately convey the object to be scanned, a relatively large frictional force is required in the pair of rollers, and for this reason, the material forming each roller must be selected to be fairly soft. It won't happen.

Therefore, when the object to be scanned is not conveyed, if the rollers are in a pressed state through the elastic force of the elastic body, the rollers may be deformed because they are made of a soft material. There is a risk of it getting lost. The object to be scanned, which is held and conveyed by the pair of rollers that have been deformed in this way, has a conveyance speed that changes due to the deformation of the pair of rollers in the sub-scanning direction, making it impossible to scan or record the image of the object to be scanned. Concerns regarding accuracy have been raised.

The present invention has been made in view of the above, and when a sheet body such as a stimulable phosphor sheet or a photographic light-sensitive material is sandwiched and conveyed between a pair of rollers and scanned, the A clearance smaller than the thickness of the sheet body is provided so that when the sheet body enters or leaves the pair of rollers, one roller is displaced in a direction away from the other roller under the action of an actuator. By configuring this structure, impact etc. are not caused to the sheet body, and furthermore, it is possible to avoid deformation of each roller due to the pair of rollers being separated when the sheet body is not conveyed. It is an object of the present invention to provide a light beam scanning mechanism that can accurately and smoothly convey a sheet in the sub-scanning direction to suitably read an image or record a visible image.

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. The light beam scanning mechanism performs scanning, and is configured to provide a gap smaller than the thickness of the object to be scanned between a pair of rollers that sandwich and convey the object to be scanned, and at least one of the pair of rollers. The present invention is characterized in that it includes a roller displacement means that displaces one of the rollers to widen the gap.

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 conveyance belt for conveying the stimulable phosphor sheet A. 18 are 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 horizontally.
A plurality of rollers 20a to 20d arranged in the vertical direction are provided on one surface of the roller so as to be in sliding contact with the roller. Furthermore, a large-diameter roller 22 is disposed at the lower bent portion of the first conveyor belt 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 basically consists of an image reading section 26 and a sheet conveying section 28 located below the reading section 26 and provided at a slight distance from the terminal end of the first conveying belt 18. has been done.

The reading unit 26 includes a laser light source 30, and the laser light source 30 has a laser light source 30 on the laser light output side.
A mirror 34, a galvanometer mirror 36, and a condensing reflecting mirror 38 are provided for scanning the light beam 2 onto the sheet. 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 pair of rollers 44 and a second pair of rollers 46, and a space between the pair of rollers 44 and 46 is for holding the stimulable phosphor sheet A to be conveyed. guide members 48a, 4
8b is arranged. The first 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 52 disposed above the roller 50. It consists of a roller 56. In this case, the first
The roller pair 44 is configured as shown in FIGS. 2 and 3, and the second roller pair 46 is also configured in the same manner as the first roller pair 44, so a detailed description of the second roller pair 46 will be given below. is omitted.

That is, shafts 50a 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. This roller 50 is, for example, a second
It is configured to engage with a roller 54 constituting the roller pair 46 via a belt or the like, and to rotate under the driving action of a rotational drive source (not shown) that is engaged with the roller 54. Moreover, the shafts 52a, 52 of the roller 52
b fit into oblong holes 60a and 60b formed in the support plates 58a and 58b, respectively, and in this case, when the roller 52 is located at the lowest end, a gap 62 is created between the roller 52 and the roller 50. defined (third
(see figure). 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 0.7 mm. If so, it is preferable to select the gap 62 to be approximately 0.2 mm to 0.4 mm. Furthermore, shafts 52a and 52b of the roller 52
Pressing members 64a and 64b are engaged with.

The pressing member 64a has a U-shape, and its upper part 66a bulges in the horizontal direction, and a groove 68a for fitting the shaft 52a is formed in the lower surface of the upper part 66a. The pressing member 64a
A lower portion 70a of the coil spring 70a bulges out in the horizontal direction like the upper portion 66a, and one end of a coil spring 72a engages with this lower portion 70a. Although not shown, the other end of the coil spring 72a is fixed within the image reading device 10, and the pressing member 64a is pressed vertically downward by the elastic force of the coil spring 72a. On the other hand, the pressing member 6
4b is constructed in the same manner as the above-described pressing member 64a, and in this case, the same reference numerals are given the same suffix b for the same components, and detailed explanation thereof will be omitted.

Next, a roller displacement means 74 is engaged with the roller 52 for vertically moving the roller 52 through the oblong holes 60a and 60b. an electromagnetic actuator constituting the roller displacement means 74;
For example, the rotary solenoid 76 is connected to the support plate 58a.
This rotary solenoid 76
One end of a first arm 78 is fixed to a rotary drive shaft 76a extending from the rotary drive shaft 76a. The other end of the first arm 78 engages with a bearing 82 provided at one end of a second arm 80, and in this case, the second arm 80 has both ends attached to respective support plates 58 at approximately the center thereof.
A rotary shaft 86 rotatably supported by a and 58b is fitted and engaged. Further, a locking portion 80a is formed at the other end of the second arm 80 via a stepped portion, and the shaft 52a of the roller 52 is placed on this locking portion 80a. 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 then in FIG. I'll keep it. Note that a large-diameter roller 94 is disposed at the lower bent portion of the second conveyor belt 92. Furthermore, the second conveyor belt 9
A plurality of rollers 9 are provided in the vertically extending portion of 2.
6a to 96e are disposed in sliding contact with each other, and 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. It is composed of A receive magazine 102 for storing the stimulable phosphor sheet A is provided adjacent to the roller 100b.

Furthermore, an erasing section 104 is disposed within the chamber 12, for example, between rollers 96b and 96c provided on the conveyor belt 92. Note that the erasing section 1
A plurality of erasing light sources (not shown) are disposed inside 04.

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 14 stores a plurality of stacked stimulable phosphor sheets A on which radiation images of a subject such as a human body are stored, for example.

Therefore, the stimulable phosphor sheet A is attached to the suction cup 1.
The sheets are taken out one by one from the supply magazine 14 under the action of a single sheet mechanism including a suction cup 16.
The sheet is transported to the sheet transport section 28 side via the first transport belt 18 provided below, a plurality of rollers 20a to 20d, and a roller 22.

Here, the roller displacement means 74 is driven. That is, when the rotary drive shaft 76a rotates in the direction of arrow B under the driving action of the rotary solenoid 76, the first arm 78 that is engaged with the rotary drive shaft 76a
similarly swings in the direction of arrow B, and presses the bearing 82 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 is rotated around the rotation axis 86.
The locking portion 80a formed at the tip thereof swings in the direction of arrow C. At this time, the other arm 88 is attached to the rotating shaft 86,
A locking portion 88 formed at the tip of this arm 88
Similarly, a also swings in the direction of arrow C. Therefore, the shaft 5 that engages with the respective locking portions 80a and 88a
2a, 52b are guided into the oblong holes 60a, 60b and are displaced upward in the vertical direction against the elastic force of the coil springs 72a, 72b that engage the pressing members 64a, 64b. In the end, the respective shafts 52a, 52b
The roller 52 providing the phosphor sheet A is separated from the roller 50 by at least the thickness of the stimulable phosphor sheet A being conveyed (see FIG. 4a).

Therefore, when the stimulable phosphor sheet A enters between the rollers 50 and 52, the roller displacement means 74
The rotary solenoid 76 constituting the motor 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 arrow D, contrary to the above, and the first arm 78 that engages with this rotary drive shaft 76a similarly swings in the direction of arrow D. . Therefore, the holding action of the shafts 52a and 52b by the second arm 80 and the arm 88 is released, and the shaft 5
2a and 52b are displaced vertically downward via pressing members 64a and 64b that engage with coil springs 72a and 7b, and the stimulable phosphor sheet 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 50 A coil spring 72 is connected to the shafts 52a, 52b via pressing members 64a, 64b.
The elastic forces of a and 72b act directly. As a result, the stimulable phosphor sheet A is suitably held between the first pair of rollers 44 by the elastic force of the coil springs 72a and 72b.

The rollers 5 constituting the second roller pair 46
When the roller 54 is rotated under the driving action of a rotational drive source (not shown) connected to the roller 4, the roller 50, which is engaged with the roller 54 via a belt or the like, rotates, and the stimulable phosphor sheet A is rotated. 1 roller pair 44
It is conveyed to the second roller pair 46 side while being held between the two rollers.

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 beam 32 emitted from the laser light source 30 is reflected by the mirror 34 to reach the galvanometer mirror 36, and the laser beam 32 is scanned on the sheet A while the galvanometer mirror 36 is oscillating. Thereby, the stimulated luminescence light emitted from the sheet A is made to enter the light guide 40 either directly or by being reflected by the reflecting mirror 38, and is converted into an electrical signal by the photomultiplier 42, for example, to record an image. Supply to equipment, etc.

At this time, the leading end side of the stimulable phosphor sheet A conveyed in the direction of arrow E via the first pair of rollers 44 faces the second pair of rollers 46 . Here, the first
A roller 56 constituting the second roller pair 46 similar to the roller pair 44 is separated from the roller 54 via a roller displacement means (not shown) (see FIG. 4b). Further, after the stimulable phosphor sheet A enters between the respective rollers 54 and 56, the roller 56 is displaced downward and the stimulable phosphor sheet A is moved by the second roller pair 46. grasp. Then, the stimulable phosphor sheet 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 rotary drive source (not shown) connected to the roller 54, while the reading section 26 is being conveyed. Scanning and reading of the stimulable phosphor sheet A is continued under the driving action. Therefore, the stimulable phosphor sheet A during scanning scanning is
It is possible to enter the roller pair 46 extremely smoothly without causing an impact or the like, and it is possible to perform the scanning and reading operation with high precision.

Further, as the stimulable phosphor sheet A is conveyed in the direction of arrow E, the rear end side of the stimulable phosphor sheet A tends to separate from the first pair of rollers 44 . In this case, similarly to the above, the roller displacement means 74
By driving the rollers 52 to displace the rollers 52 upward in the vertical direction, shocks that are likely to occur when the ends of the stimulable phosphor sheet A are separated from the first pair of rollers 44 are avoided, and the reading unit 26 The scanning reading operation can be carried out suitably (see Fig. 4c).

Therefore, the stimulable phosphor sheet 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. , and all of the image signals are read by passing through the reading section 26.

Next, the stimulable phosphor sheet A is transferred to the second conveyor belt 92, the roller 94, and the rollers 96a, 9.
6b to the erasing unit 104. The erasing section 1
At 04, a plurality of erasing light sources (not shown) are turned on, and therefore, 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 and the rollers 96c to 96e.
The receive magazine 1 is conveyed to the upper part of the image reading device 10 via the rollers 98 and rollers 100a and 100b, and is displaced in its advancing direction.
It is stored in 02.

In this case, for example, the rollers 52 constituting the first roller pair 44 are configured to slide on the surface of the stimulable phosphor sheet A and convey the stimulable phosphor sheet A. Therefore, in particular, the roller 5
2 is made of a soft material such as polyurethane rubber so as not to cause scratches on the surface of the stimulable phosphor sheet A. Therefore, if the rollers 50 and 52 are in constant pressure contact, especially the roller 52 will be deformed, and the stimulable phosphor sheet A held between the rollers 52 and 50 will be accurately moved in the sub-scanning direction. It becomes difficult to transport.
Moreover, in order to convey the stimulable phosphor sheet A more effectively through the roller pair 44,
It is necessary to make each roller 50, 52 of a considerably soft material to increase the frictional force with the stimulable phosphor sheet A. In this case, the roller 50
Also, if the rollers 52 are in pressure contact, the respective rollers 5
The deformation caused at 0.52 will be quite large.

However, in this embodiment, a gap 62 is provided between the respective rollers 50 and 52 when the stimulable phosphor sheet A is not conveyed, and a gap 62 is provided between the rollers 50 and 52 when the stimulable phosphor sheet A is not conveyed. The stimulable phosphor sheet A is sandwiched between the rollers 50 and 52 only occasionally. Therefore, even if the rollers 50 and 52 are made of a soft material, the rollers 50 and 52 will not be deformed, and the stimulable phosphor sheet A can be accurately conveyed in the sub-scanning direction. It will be readily understood that in the second roller pair 46 as well, desired materials can be used for the respective rollers 54 and 56.

Furthermore, in this embodiment, the stimulable phosphor sheet A is
6 and when leaving the pair of rollers 44, 46, each roller 52, 56 is separated from the other roller 50, 54. Therefore, the stimulable phosphor sheet A enters the respective roller pairs 44 and 46 or the roller pair 4
The stimulable phosphor sheet A can be conveyed extremely smoothly in the sub-scanning direction while suitably avoiding shocks that are likely to occur when detached from the stimulable phosphor sheet A. As a result, it is possible to achieve the effect that the scanning reading operation by the reading section 26 is performed with even higher accuracy. In addition,
In the embodiment described above, the grip of the stimulable phosphor sheet A by the first pair of rollers 44 is released when the sheet A leaves the pair of rollers 44.
When the leading edge of the sheet A is gripped by the second pair of rollers 46, the grip of the sheet A by the first pair of rollers 44 may be released, and sub-scanning conveyance may be performed thereafter only by the second pair of rollers 46.

As described above, according to the present invention, when scanning an object to be scanned such as a stimulable phosphor sheet, the object to be scanned is conveyed while being held between a pair of rollers, and the object to be scanned is conveyed between a pair of rollers. A predetermined clearance is provided in advance, and one roller is configured to be movable.
Therefore, even if the rollers are formed of a relatively soft material, since the rollers are spaced apart from each other, deformation or the like will not occur in the rollers. as a result,
The object to be scanned can be transported in the sub-scanning direction with high precision, and the scanning reading or scanning recording operation on the object to be scanned can be performed accurately.
Moreover, by relatively displacing the pair of rollers so that the distance between the rollers is larger than the thickness of the object to be scanned, an impact or the like is caused to the object to be scanned that is about to enter or leave between the pair of rollers. This makes it possible to perform scanning reading or scanning recording work with high precision.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to this embodiment. For example, a torque motor or the like may be used instead of a rotary solenoid as the roller displacement means. Of course, various improvements and changes in design are possible without departing from the gist of the present invention.

[Brief explanation of the drawing]

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 the light beam scanning mechanism according to the present invention, and FIG.
The figure is a schematic side view of the main part of the light beam scanning mechanism according to the present invention, and FIGS. 4a to 4c are schematic diagrams illustrating the operation of the light beam scanning mechanism according to the present invention. 10... Image reading device, 12... Room, 14...
Supply magazine, 18... Conveyor belt, 24...
...Light beam scanning mechanism, 26...Reading unit, 28...
Sheet body conveyance section, 30... Laser light source, 44, 4
6... Roller pair, 50, 52, 54, 56... Roller, 64a, 64b... Pressing member, 72a, 7
2b... Coil spring, 74... Roller displacement means, 76... Rotary solenoid, 78, 80
...Arm, 86...Rotation axis, 88...Arm,
92... Conveyor belt, 102... Receive magazine, 104... Eraser section.

Claims (1)

[Claims] 1. A light beam 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. The scanning mechanism is configured to provide a gap smaller than the thickness of the object to be scanned between a pair of rollers that sandwich and convey the object to be scanned, and at least one of the pair of rollers is displaced. 1. A light beam scanning mechanism, comprising: a roller displacement means for widening the gap. 2. In the mechanism set forth in claim 1,
The pair of rollers includes a first roller that is engaged with a rotational drive source and rotates, and a first roller that is fitted into a guide hole and rotated.
a second roller that defines a gap between the roller and the first roller and is pressed toward the first roller through a pressing means, and the second roller is pushed by the pressing means under the action of a roller displacement means. A light beam scanning mechanism configured to expand a gap between the first roller and the second roller by displacing the light beam along the guide hole against pressure. 3. In the mechanism according to claim 1 or 2, the roller displacement means substantially includes a rotational drive source and a first roller that is engaged with and oscillates on the rotational drive source.
a second arm that is rotatable and has one end engaged with the first arm and the other end engaged with one of the rollers.
an arm, and configured to displace the one roller in a direction away from the other roller via the first and second arms under the action of the rotational drive source. 4 In the mechanism set forth in claim 2,
The pressing means includes a pressing member and a spring, and the first
When the object to be scanned enters between the roller and the second roller, the pressing member presses the second roller toward the first roller through the elastic force of the spring. A light beam scanning mechanism in which the object to be scanned is held between a roller and a second roller. 5. A light beam scanning mechanism according to any one of claims 1 to 4, in which the object to be scanned is a stimulable phosphor sheet. 6. A light beam scanning mechanism according to any one of claims 1 to 4, in which the object to be scanned is made of a photosensitive material.