Electron beam irradiation device

Abstract

To prevent radiation leaking from shielding measures from reaching specific areas. [Solution] The electron beam irradiation device (100) comprises an electron beam generator (4) that generates an electron beam, a transport cylinder (5) that transports the paper (P) so that it passes through the irradiation area (IR) irradiated by the electron beam by holding and rotating a part of the paper (P) to be irradiated by the electron beam, a shielding structure (8) provided around the irradiation area (IR) in the transport cylinder (5) to shield the radiation, and a guide structure (10) that guides the radiation leaked from the end of the shielding structure (8) in a specified direction.

Description

Technical Field

[0001] The present disclosure relates to an electron beam irradiation apparatus that irradiates an object to be irradiated with an electron beam.

Background Art

[0002] In an electron beam irradiation apparatus, an object to be irradiated is conveyed so as to pass through an irradiation region where an electron beam is irradiated, thereby irradiating the object to be irradiated with the electron beam. Further, in an electron beam irradiation apparatus, since radiation is generated accompanying the irradiation of the electron beam, the radiation is shielded so that the radiation does not leak to the outside.

[0003] For example, Patent Document 1 describes an electron beam irradiation apparatus that holds a printed object as an object to be irradiated by a gripper device provided on the surface of a rotating cylinder and conveys it so as to pass through an electron beam irradiation region. In the electron beam irradiation apparatus, shielding means for shielding X-rays is provided around the electron beam irradiation region in the cylinder.

[0004] The shielding means has a curved surface formed at a certain interval from the surface of the cylinder and is provided in a predetermined range from the end of the electron beam irradiation region. The X-rays leaked from the end of the shielding means are irradiated downward, reflected by the lower end surface of the electron beam irradiation apparatus or the floor surface, and reflected in the direction of the upper part of the apparatus.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] A space may be provided above the above-described electron beam irradiation apparatus for an operator to enter for maintenance of the electron beam generation unit. There is a possibility that the X-rays reflected downward as described above may reach this space.

[0007] One aspect of this disclosure aims to prevent radiation leaking from a shielding means from reaching a specific area. [Means for solving the problem]

[0008] To solve the above problems, an electron beam irradiation apparatus according to one aspect of the present disclosure comprises: an electron beam generator that generates an electron beam; a cylindrical body that carries the object to be irradiated by the electron beam by holding and rotating a part of the object to be irradiated so that it passes through the irradiation area to which the electron beam is irradiated; a shielding structure provided around the irradiation area in the cylindrical body for shielding radiation; and a guide structure for guiding the radiation leaking from the end of the shielding structure in a specified direction. [Effects of the Invention]

[0009] According to one aspect of this disclosure, it is possible to prevent radiation leaking from a shielding means from reaching a specific area. [Brief explanation of the drawing]

[0010] [Figure 1] This is a cross-sectional view showing the configuration of an electron beam irradiation apparatus according to one embodiment of the present disclosure. [Figure 2] This is a perspective view showing the configuration of the guide structure in the electron beam irradiation apparatus described above. [Modes for carrying out the invention]

[0011] [Embodiment] One embodiment of this disclosure will be described in detail below.

[0012] <Configuration of the electron beam irradiation device> Figure 1 is a cross-sectional view showing the configuration of the electron beam irradiation apparatus 100 according to this embodiment. Figure 2 is a perspective view showing the configuration of the guide structure 10 in the electron beam irradiation apparatus 100.

[0013] As shown in Figure 1, the electron beam irradiation device 100 irradiates the paper P (object to be irradiated) with an electron beam generated by the electron beam generator 4 for printing. To this end, the electron beam irradiation device 100 transports the paper P so that it passes through the irradiation area IR where the electron beam is irradiated by rotating the transport cylinder 5 (cylindrical body). The electron beam irradiation device 100 also shields the radiation generated when the electron beam irradiates the transport cylinder 5 (metal) with a shielding structure 8. The electron beam irradiation device 100 comprises a housing 1, a shielding cover 2, a pair of support members 3, an electron beam generator 4, a transport cylinder 5, a supply body 6, a discharge body 7, a shielding structure 8, a shielding plate 9, and a guide structure 10.

[0014] The housing 1 is a structure that covers the transport cylinder 5, the supply body 6, the discharge body 7, the shielding structure 8, the shielding plate 9, and the guide structure 10. The housing 1 has a bottom plate 1a, a pair of partition plates 1b, and a top cover plate 1c. The pair of partition plates 1b are formed to rise from the rear and front edges of the electron beam irradiation device 100 on the bottom plate 1a and to face each other.

[0015] The housing 1 has open left and right sides in Figure 1 to allow for the supply of paper P to the supply unit 6 and the receipt of paper P from the discharge unit 7. In addition, the top of the housing 1 on the discharge unit 7 side is open to facilitate maintenance of the shielding structure 8, transport cylinder 5, and discharge unit 7, which will be described later.

[0016] The upper cover plate 1c is positioned from the lower end of the wall portion on the supply body 6 side of the shielding cover 2 (described later) to one side end of the electron beam irradiation device 100 (the right end in Figure 1). The upper cover plate 1c is provided to cover the area above the supply body 6 of the pair of partition plates 1b. The upper cover plate 1c is rotatable around a hinge structure (not shown) provided near the lower end of the wall portion of the shielding cover 2.

[0017] During normal use and non-use of the electron beam irradiation apparatus 100, the upper cover plate 1c is closed at the position shown in FIG. 1. The closed upper cover plate 1c is a specific area around the electron beam generator 4. An operator stands on the upper cover plate 1c and performs operations such as maintenance of the electron beam generator 4. Also, during maintenance of the transfer cylinder 5, the supply body 6, the shielding structure 8, etc., the upper cover plate 1c is rotated and opened toward the electron beam generator 4 side.

[0018] In addition, in FIG. 1, only the partition plate 1b on the back side is shown, and the partition plate 1b on the front side is omitted. Also, the structure of the housing 1 described above is merely an example and is not limited to this structure.

[0019] The shielding cover 2 is a box-shaped cover that shields the electron beam generator 4. The basic structure of the shielding cover 2 is formed of lead, and the inner and outer surfaces of the basic structure are covered with a stainless steel layer for rust prevention and strength assurance.

[0020] The pair of support members 3 are members that support the shielding structure 8 described later. The pair of support members 3 are fixed to the inner surfaces of the pair of partition plates 1b by bolt fastening so as to be arranged at positions facing each other.

[0021] The electron beam generator 4 accelerates a wide electron beam generated by the electron source 42 in the vacuum chamber 41 by an electric field due to the application of a DC high voltage. The electron beam generator 4 irradiates the electron beam obliquely downward toward the irradiation region IR by transmitting the accelerated electron beam through a metal foil provided on the irradiation window 43.

[0022] The electron beam generator 4 irradiates an electron beam downward by being provided at the upper part of the electron beam irradiation apparatus 100. Specifically, the electron beam generator 4 is generally arranged above the first transfer position where the gripping mechanisms 52, 62 described later transfer the paper P, and irradiates the electron beam obliquely downward toward the central axis 51a of the cylinder body 51.

[0023] The conveying cylinder 5 holds the sheet-like paper P supplied from the supplier 6 and rotates it, thereby conveying it so as to pass through the irradiation region IR. The conveying cylinder 5 has a cylinder main body 51 and a pair of gripping mechanisms 52.

[0024] The cylinder main body 51 has a central axis 51a at both ends. One end of the central axis 51a is rotatably supported by the partition plate 1b shown on the back side of the housing 1, and is rotationally driven by a drive mechanism (not shown) fixed to the back side of this partition plate 1b. The other end of the central axis 61a is rotatably supported by a partition plate 1b (not shown) on the front side of the housing 1.

[0025] A pair of recesses 51c are provided on the outer peripheral surface 51b of the cylinder main body 51. The pair of recesses 51c are formed so as to be located on opposite sides with the central axis 51a in between. In other words, the pair of recesses 51c are arranged at an interval of 180° with respect to the central axis 51a.

[0026] The pair of gripping mechanisms 52 are mechanisms that hold one end of the paper P so as to grip it. The gripping mechanism 52 is disposed inside the recess 51c. The gripping mechanism 52 has a fixed portion 52a, a movable portion 52b, and a support shaft 52c. The fixed portion 52a is fixed to the bottom surface of the recess 51c. The movable portion 52b is movable with respect to the fixed portion 52a and is formed in a tapered shape that becomes thinner as it approaches the tip. The movable portion 52b is driven by a drive device (not shown). The support shaft 52c supports the movable portion 52b so as to be rotatable with respect to the fixed portion 52a.

[0027] In the gripping mechanism 52 configured as described above, the movable portion 52b rotates toward the inner surface of the recess 51c, and thereby grips one end of the paper P with the inner surface. Further, the movable portion 52b rotates to the opposite side of the inner surface, and thereby releases the paper P away from the inner surface.

[0028] The supply unit 6 holds and rotates the paper P supplied from a paper introduction mechanism (not shown) to a predetermined first transfer position, where it transfers the paper P to the transport cylinder 5. For this reason, the supply unit 6 is positioned upstream of the transport cylinder 5 in the direction of paper P transport. The supply unit 6 has a rotating body 61 and a pair of gripping mechanisms 62.

[0029] The rotating body 61 is a cylindrical body having central axes 61a at both ends, with a cross-section perpendicular to the central axes 61a formed, for example, in a rhombic shape. The central axes 61a are rotatably supported by a pair of partition plates 1b and are rotationally driven by a drive mechanism (not shown). The tip portion 61b of the rotating body 61 is provided with a pair of recesses 61c having a structure similar to the pair of recesses 51c. The pair of gripping mechanisms 62 are mechanisms for holding one end of the paper P. The gripping mechanism 62 has a fixed portion 62a, a movable portion 62b, and a support shaft 62c, and operates in the same manner as the gripping mechanism 52.

[0030] The discharge unit 7 holds the paper P received from the transport cylinder 5 at a predetermined second transfer position and rotates, thereby transporting the paper P to a transfer position with a paper discharge mechanism (not shown), and at that transfer position, it transfers the paper P to the paper discharge mechanism. For this reason, the discharge unit 7 is positioned downstream of the transport cylinder 5 in the direction of transport of the paper P. The discharge unit 7 has a rotating body 71 and a pair of gripping mechanisms 72.

[0031] The rotating body 71 is a cylindrical body having central axes 71a at both ends, and its cross-section perpendicular to the central axes 71a is formed, for example, in a rhombic shape. The central axes 71a are rotatably supported by a pair of partition plates 1b and are rotationally driven by a drive mechanism (not shown). The tip portion 71b of the rotating body 71 is provided with a pair of recesses 71c having a structure similar to the pair of recesses 51c. The pair of gripping mechanisms 72 are mechanisms for holding one end of the paper P. The gripping mechanism 72 has a fixed part 72a, a movable part 72b, and a support shaft 72c, and operates in the same manner as the gripping mechanism 72.

[0032] The shielding structure 8 is a structure that shields against radiation generated when the electron beam is irradiated into the irradiation area IR. The shielding structure 8 is provided in the vicinity of the irradiation area IR in the transport cylinder 5, within a predetermined range from the irradiation area IR. Specifically, the shielding structure 8 extends from directly above the first transfer position described above to directly above the second transfer position where the gripping mechanisms 52 and 72 transfer the paper P. The shielding structure 8 is provided with a through hole 8a for the electron beam irradiated into the irradiation area IR to pass through.

[0033] The shielding structure 8 is formed as a semi-cylindrical body, such that a cylindrical body is divided along its central axis. The shielding structure 8 has a curved surface on its inner surface that is formed at a predetermined distance from the outer surface 51b of the conveying cylinder 5. The shielding structure 8 is fixed to a pair of support members 3 via brackets (not shown) at both ends facing the pair of partition plates 1b.

[0034] Because the gripping mechanism 52 is provided on the transport cylinder 5, the paper P is lifted up relative to the outer surface 51b, and the gripping mechanism 52 protrudes from the outer surface 51b. For this reason, a predetermined gap, for example 10 mm, needs to be provided between the outer surface 51b and the shielding structure 8.

[0035] The shielding plate 9 shields the space between the second member 82 on the first transfer position side in the shielding structure 8 and the inner surface of the lower end of the shielding cover 2 on the supply body 6 side. Like the first member 81, the shielding plate 9 is composed of a main body made of lead and an outer cover made of stainless steel.

[0036] The guide structure 10 is a structure that guides radiation leaking from the end of the cylinder body 51 in the shielding structure 8 that is parallel to the central axis 51a (hereinafter referred to as the "shielding end") in a specified direction. As shown in Figure 2, the guide structure 10 has a reflection unit 11, a support plate 12, a pair of support bars 13, and a pair of support bars 14.

[0037] The reflective unit 11 has an opening 11a, a bottom plate portion 111, a first side plate portion 112, a second side plate portion 113, a third side plate portion 114, and a fourth side plate portion 115. The bottom plate portion 111 is fixed on a support plate 12. The first side plate portion 112, the second side plate portion 113, the third side plate portion 114, and the fourth side plate portion 115 are formed to rise from the outer peripheral ends of each side of the bottom plate portion 111, and adjacent portions are connected at their respective side ends. With this structure, the reflective unit 11 has an opening 11a at its top.

[0038] The reflective unit 11 has multiple reflective surfaces 111a, 112a, 113a, 114a, and 115a formed on the inner surfaces of the bottom plate portion 111, the first side plate portion 112, the second side plate portion 113, the third side plate portion 114, and the fourth side plate portion 115, respectively. As a result, the reflective unit 11 reflects the radiation incident from the opening 11a with the multiple reflective surfaces 111a, 112a, 113a, 114a, and 115a, guiding it in a specified direction.

[0039] The first side plate portion 112 is positioned on the side of the central axis 61a of the supply body 6, such that its reflective surface 112a faces one side of the electron beam irradiation device 100 (the left side in Figure 1). The first side plate portion 112 is supported on the support plate 12 by a pair of support bars 13. The first side plate portion 112 is inclined with respect to the bottom plate portion 111 so as to reflect radiation leaking from the shielding end of the shielding structure 8 to the bottom plate portion 111. Specifically, the first side plate portion 112 is slightly inclined such that its upper end is closer to a hypothetical plane hanging down from the central axis 61a of the supply body 6 than its lower end.

[0040] The second side plate portion 113 is positioned on the side of the transport cylinder 5, facing the first side plate portion 112. The second side plate portion 113 is supported on the support plate 12 by a pair of support bars 14. The second side plate portion 113 is inclined with respect to the bottom plate portion 111 so as to reflect radiation reflected from the bottom plate portion 111 upward (towards the vicinity of the first handover position). Specifically, the second side plate portion 113 is inclined at a larger angle than the first side plate portion 112 such that its upper end is closer to a hypothetical plane hanging down from the central axis 61a of the supply body 6 than its lower end.

[0041] The third side plate portion 114 is positioned near the front partition plate 1b of the electron beam irradiation device 100, parallel to this partition plate 1b. The fourth side plate portion 115 is positioned near the rear partition plate 1b of the electron beam irradiation device 100, parallel to this partition plate 1b. The third side plate portion 114 and the fourth side plate portion 115 are positioned parallel to each other and facing each other.

[0042] <Reflection of radiation> In the electron beam generator 4 configured as described above, the shielding structure 8 is divided into a first range on the supply side 6 and a second range on the discharge side 7, with the irradiation area IR in between. In the shielding structure 8, the first range is about half the length of the second range and is therefore short.

[0043] Therefore, in the second range, a sufficiently long distance is ensured from the irradiation area IR to the shielding end of the shielding structure 8. Consequently, the radiation generated in the irradiation area IR is sufficiently attenuated in the second range by being reflected multiple times by the outer surface 51b of the cylinder body 51 and the inner surface of the shielding structure 8. Thus, when the radiation leaking from the leakage end on the second range side of the shielding structure 8 is irradiated downwards, reflected by the bottom plate 1a of the housing 1, and travels upwards, its intensity is sufficiently attenuated to a level that does not affect the human body by changing its direction of travel several times.

[0044] On the other hand, the radiation generated in the irradiated IR region is reflected only once between the outer surface 51b of the cylinder body 51 and the inner surface of the shielding structure 8 within the first range. Therefore, the radiation leaks out from the shielding end of the shielding structure 8 without its intensity being sufficiently reduced.

[0045] Radiation leaking from the shielding end in the first range of the shielding structure 8 travels diagonally downward as shown by the dashed line in Figure 1 and enters the interior of the reflecting unit 11 through the opening 11a. This radiation is first reflected by the reflecting surface 112a of the first side plate portion 112, then a portion of it is reflected by the reflecting surface 111a of the bottom plate portion 111, and further reflected by the reflecting surface 113a of the second side plate portion 113, before traveling in the direction toward the first handover position as specified. In addition, the remaining portion reflected by the reflecting surface 112a is reflected by the reflecting surfaces 113a and 115a of the third side plate portion 114 and the fourth side plate portion 115, respectively, and travels in the direction toward upward as specified. These specified directions are defined as directions that do not lead toward the top cover plate 1c, which is the work area.

[0046] Thus, the radiation incident on the guide structure 10 travels in the direction specified above and does not reach the upper cover plate 1c.

[0047] <Effects of electron beam irradiation device> In the electron beam generator 4, the guide structure 10 has a reflection unit 11 that guides the radiation leaking from the end of the shielding structure in a specified direction. The specified direction is set to avoid the work area where an operator enters the electron beam irradiation device. This prevents the radiation from reaching the upper cover plate 1c, which is the work area.

[0048] The reflective unit 11 has an opening 11a and a plurality of reflective surfaces 111a, 112a, 113a, 114a, and 115a. As a result, the reflective unit 11 reflects radiation incident from the shielding end of the shielding structure 8 through the opening 11a using the reflective surfaces 111a, 112a, 113a, 114a, and 115a. In the reflective unit 11, the radiation can be easily guided in a specified direction by adjusting the angles of each of the reflective surfaces 111a, 112a, 113a, 114a, and 115a.

[0049] Furthermore, the radiation that propagates after being reflected by the reflective surfaces 111a, 112a, 111a, and 113a is reflected three times within the reflection unit 11. Radiation has the property that its intensity decreases as it changes direction of propagation as it travels through the air. Therefore, the radiation emitted from the reflection unit 11 is significantly attenuated by the three reflections. Consequently, the intensity of the radiation is sufficiently attenuated to the point where it does not affect the human body.

[0050] The reflection unit 11 guides radiation leaking from the shielding end of the shielding structure 8 to a specific area around the electron beam generator 4, i.e., the area excluding the top cover plate 1c. Since radiation does not reach the top cover plate 1c, workers standing on the top cover plate 1c can avoid being affected by radiation. Furthermore, workers can avoid being affected by radiation when opening the top cover plate 1c for maintenance inside the housing 1.

[0051] 〔summary〕 An electron beam irradiation apparatus according to a first aspect of the present disclosure comprises: an electron beam generator that generates an electron beam; a cylindrical body that carries an object to be irradiated by the electron beam by holding and rotating a part of the object to be irradiated so that it passes through an irradiation area to be irradiated by the electron beam; a shielding structure provided around the irradiation area in the cylindrical body for shielding radiation; and a guiding structure for guiding radiation leaking from the end of the shielding structure in a specified direction.

[0052] In the above configuration, if the direction in which the radiation is guided is set in the electron beam irradiation device to avoid the work area where the worker enters, the radiation can be prevented from reaching the work area.

[0053] In the first embodiment, the electron beam irradiation apparatus according to a second aspect of the present disclosure has a guide structure having an opening and a plurality of reflective surfaces, and the radiation incident from the opening may be guided in the specified direction by reflecting it off the plurality of reflective surfaces.

[0054] In the above configuration, radiation can be easily guided in a specified direction by adjusting the angle of each of the multiple reflective surfaces.

[0055] In a third aspect of the present disclosure, an electron beam irradiation apparatus, in the first or second aspect, is provided above the cylindrical body to irradiate the electron beam downward, and the shielding structure is provided in an area around the irradiation area where the object to be irradiated is transported, and has a curved surface formed along the outer surface of the cylindrical body at a predetermined distance from the outer surface, and is provided within a predetermined range from the irradiation area, and the guide structure guides the radiation leaking from the end of the shielding structure to an area excluding a specific area around the electron beam generator.

[0056] According to the above configuration, radiation does not reach the specific area, thus preventing workers who enter that area from being affected by radiation.

[0057] [Additional Notes] This disclosure is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in each embodiment are also included within the technical scope of this disclosure. [Explanation of Symbols]

[0058] 1c Upper cover plate (specific area) 4. Electron beam generator 5. Conveying cylinder (cylindrical body) 8 Shielding structure 10 Guide Structure 11a opening 100 Electron beam irradiation equipment 111a~115a Reflective surface P Paper (object to be irradiated) IR irradiation area

Claims

1. An electron beam generator that generates an electron beam, A cylindrical body that holds and rotates a portion of the object to be irradiated by the electron beam, thereby transporting the object to be irradiated so that it passes through the irradiation area to which the electron beam is irradiated, A shielding structure is provided around the irradiation area of ​​the cylindrical body to shield against radiation, An electron beam irradiation device comprising a guide structure for guiding the radiation leaking from the end of the shielding structure in a specified direction.

2. The electron beam irradiation apparatus according to claim 1, wherein the guide structure has an opening and a plurality of reflective surfaces, and guides the radiation incident from the opening in the specified direction by reflecting it off the plurality of reflective surfaces.

3. The electron beam generator is provided above the cylindrical body to irradiate the electron beam downwards. The shielding structure is provided in the area around the irradiation region where the object to be irradiated is transported, and has a curved surface formed along the outer surface of the cylindrical body at a predetermined distance from the outer surface of the cylindrical body. The electron beam irradiation apparatus according to claim 1 or 2, wherein the guide structure guides the radiation leaking from the end of the shielding structure to an area excluding a specific area around the electron beam generator.

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