JP2002202611A - Fixing device for sheet body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a rotary drum from losing the balance of rotation when the rotary drum is rotated at a high speed in order to securely fix a sheet body. SOLUTION: A clamp 100 forming a front end chuck 62 is provided with a fulcrum PA near a clamping section 102 projected from a device body 122, by which a centroid position G is brought to the side opposite to the clamping section 102 across the fulcrum PA and a vertical distance L1 is made longer than a vertical distance L4. The energizing force F2 by a coil spring 138 is made smaller by increasing the vertical distance L2, by which the vertical distance L3 is necessitated to be shorter than the vertical distance L2. As a result, the sure fixation of a printing plate 12 is made possible and the compactification and weight reduction of the clamp are made possible. Even when the rotary drum is rotated at a high speed, the rotary drum does not lose the balance of rotation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet fixing device for fixing a peripheral portion of a sheet such as a photosensitive lithographic printing plate wound around a rotating drum rotated at a high speed by sandwiching the peripheral surface between the rotating drum and the sheet. About.

[0002]

2. Description of the Related Art Image exposure in which a photosensitive printing plate (hereinafter referred to as "printing plate") having a photosensitive layer formed on a support, such as a thin aluminum sheet used for printing, is used as a support. In some apparatuses, a printing plate is wound around a peripheral surface of a rotary drum, rotated, and the printing plate is scanned and exposed. In such an image exposure apparatus, when the printing plate is positioned and wound on the peripheral surface of the rotating drum, a fixing device that clamps and fixes the peripheral portion of the printing plate between the rotating drum and a clamp is used. .

In an image exposure apparatus using a rotating drum, a printing plate is exposed by irradiating a printing plate with a light beam modulated based on image data while rotating the rotating drum around which the printing plate is wound at a high speed. When the rotating drum is rotated at a high speed, a centrifugal force acts not only on the printing plate but also on the clamp. For this reason, the clamping force of the printing plate by the clamp is reduced, causing the printing plate to be displaced, and the image recording position on the printing plate may be displaced.

In order to prevent this, it is necessary to increase the urging force or to increase the clamping force by using centrifugal force.

On the other hand, when a printing plate is mounted on a rotating drum,
When the printing plate is removed from the rotary drum, it is necessary to swing the clamp in a direction against the urging force of the urging means by the clamping release means using a cam or the like. At this time, by configuring the cam to abut on the clamp at a position distant from the swing center of the clamp, it is possible to mount and remove the printing plate smoothly.

[0006]

However, when the biasing force for applying the printing plate clamping force to the clamp is increased,
It is necessary to strengthen the clamp, and to increase the centrifugal force, the weight of the clamp increases. In addition, the increase in the size of the clamp necessitates a further increase in the size of the clamp in order to smoothly clamp / release the sheet body by the clamp.

[0007] Such an increase in the size and weight of the clamp causes the rotation balance to be lost when the rotating drum rotates at a high speed. This causes distortion and the like.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and when the peripheral portion of a sheet wound around a rotary drum is clamped and fixed between the rotary drum and the rotary drum, the rotational balance of the rotary drum is lost. It is an object of the present invention to propose a fixing device for a sheet member that prevents the sheet member from being lost.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a rotating drum which is rotated with a sheet wound around a peripheral surface thereof, wherein the peripheral edge of the sheet is defined as a rotating drum. A fixing device for fixing the sheet body by sandwiching the sheet member between the peripheral surface of the rotating drum and the peripheral surface of the rotating drum at one end side along the circumferential direction of the rotating drum. And a clamp whose center of gravity is deviated to the other end side along the circumferential direction of the clamp unit and the rotating drum, and the clamp unit rotates the clamp in the vicinity of the clamp unit. A support shaft that is supported by the rotating drum so as to be swingable in a direction of contact and separation from the peripheral surface of the drum, and the clamp portion that clamps the sheet body between the rotating drum and the rotating drum when the rotation of the rotating drum is stopped. Of the rotating drum Urging means for urging the other end of the clamp along the circumferential direction of the rotary drum so as not to be separated from the surface; and a position supported by the support shaft and the urging when the rotary drum stops at a predetermined position. Between the urging positions by the means, by pressing the clamp against the urging force of the urging means, the clamp release means for swinging the clamp in a direction away from the peripheral surface of the rotary drum, It is characterized by including.

According to the present invention, the clamp is supported by the rotary drum near the clamp portion, and the clamp clamps the sheet body with the peripheral surface of the rotary drum by the urging force applied by the urging means.

Further, when a centrifugal force is generated in the clamp due to the rotation of the rotary drum, the sheet body is nipped by the nipping force generated by the centrifugal force in addition to the urging force of the urging means.

At this time, since the center of gravity of the clamp is deviated to the side opposite to the clamp portion and the support shaft is near the clamp portion, a large clamping force can be obtained even if the clamp is small and compact. Therefore, the sheet body can be reliably fixed by the centrifugal force generated in the clamp.

[0013] Further, if the sheet body can be held and fixed by the holding force mainly generated by the centrifugal force, the biasing means applies the biasing force suppressed to such an extent that the clamp portion does not float due to the rigidity of the sheet body or the like. Is fine.

Further, since the fixing releasing means presses the clamp between the support shaft and the biasing position of the biasing means, it is not necessary to enlarge the clamp to clamp / release the sheet body.

This makes it possible to reduce the size and weight of the clamp and prevent the clamp from breaking the rotational balance of the rotary drum even when the rotary drum rotates at high speed.

The position where the fixing releasing means presses the clamp is preferably near the biasing position of the urging means which is the end of the clamp, whereby the load on the fixing releasing means can be reduced. .

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of an image exposure apparatus 10 applied to the present embodiment. The image exposure apparatus 10 includes a photosensitive lithographic printing plate (hereinafter, referred to as a “printing plate 12”) in which a photosensitive layer is formed on a rectangular thin plate-shaped (for example, having a thickness of about 0.3 mm) support formed of, for example, aluminum or the like as a sheet body. The printing plate 12 is irradiated with a light beam modulated on the basis of image data to perform scanning exposure. The printing plate 12 that has been subjected to image exposure by the image exposure device 10 is subjected to development processing and the like by an automatic developing device (not shown) or the like.

The image exposure apparatus 10 is configured such that a cassette loading section 18, a plate feeding transport section 20, a recording section 22, a discharge buffer section 24 and the like are arranged in a machine frame 14. The cassette loading section 18 is disposed in the machine frame 14 at the lower right side in FIG. 1, and a plurality of cassettes 16 each accommodating a large number of printing plates 12 are inclined at a predetermined angle. Will be loaded.

The image exposure apparatus 10 can process a plurality of sizes of printing plates 12 having different vertical and horizontal dimensions.
The printing plate 12 of any size is accommodated in the cassette 16 with the photosensitive layer facing upward and one end positioned at a predetermined position. Further, the cassette loading section 18 is loaded with a plurality of cassettes 16 at a predetermined interval and one end of the printing plate 12 accommodated in each cassette 16 has a substantially constant height.

The plate feeding section 20 is arranged above the cassette loading section 18, and the recording section 22 is arranged at the lower center of the apparatus adjacent to the cassette loading section 18. The plate feeder 20 is provided with a pair of side plates 26 (only one is shown in FIG. 1).
8 and a single-wafer unit 30 are attached.

The reversing unit 28 includes a reversing roller 32 having a predetermined outer diameter, and a plurality of small rollers (in the present embodiment, as an example, the small roller 3 is provided around the reversing roller 32).
4A, 34B, 34C, and 34D). The small rollers 34 </ b> A to 34 </ b> D are arranged so as to extend from the cassette loading unit 18 side to above the reversing roller 32 and to the recording unit 22 side, and the endless transport belt 36 is wound therearound. As a result, the transport belt 36 is wound around the reversing roller 32 over about a half circumference between the small rollers 34A and 34D.

On the other hand, the single wafer unit 30 includes the cassette 16
A plurality of suction cups 38 for sucking the upper end portion of the printing plate 12 therein are provided.
The printing plate 12 is sucked by the suction cup 38 so as to face the upper end of the printing plate 12 in the cassette 16 loaded in the cassette 8. Further, the sheet-feeding unit 30 pulls out the printing plate 12 from the cassette 16 by moving the suction cup 38 on which the printing plate 12 has been sucked substantially upward. Insert between 36. In FIG. 1, the outline of the moving position of the suction cup 38 is indicated by a two-dot chain line.

The reversing unit 28 rotates the reversing roller 32 and the transport belt 36 in the direction in which the printing plate 12 is pulled out from the cassette 16 (the direction of arrow A in FIG. 1). As a result, the printing plate 12 is sandwiched between the reversing roller 32 and the transport belt 36 and pulled out of the cassette 16, and is wound around the reversing roller 32, thereby being transported while being curved and inverted. The reversing roller 32
Is a dimension that does not cause the printing plate 12 to break or bend when the printing plate 12 is curved (for example, 100 mm).
mm or more).

As shown by the solid line and the two-dot chain line in FIG. 1, the side plate 26 moves horizontally according to the position of the cassette 16 from which the printing plate 12 is taken out. Thus, the suction cup 38 of the sheet unit 30 is opposed to the printing plate 12 in the selected cassette 16.

The side plate 26 is provided with a guide 40 below the small roller 34D. The printing plate 12 inverted by the reversing roller 32 moves between the reversing roller 32 and the transport belt 36 on the small roller 34D side. From this guide 40
Sent out to. In addition, above the recording unit 22,
A transport conveyor 42 is provided, and the reversing unit 28
The printing plate 12 sent out of the printer is guided by the guide 40 toward the transport conveyor 42.

The guide 40 swings with the movement of the side plate 26 so that the guide direction of the printing plate 12 is always directed to the conveyor 42. The small roller 3 on the recording unit 22 side
4D moves so as to change the sending direction of the printing plate 12 from the reversing unit 28 with the movement of the side plate 26, and the small roller 34C applies a substantially constant tension to the transport belt 36 when the small roller 34D moves. Move to give. Thereby, the printing plate 1 sent out from the reversing unit 28
2 is gently curved by the guide 40.

On the conveyor 42, a conveyor belt 48 is wound between a roller 44 adjacent below the plate feeding unit 20 and a roller 46 adjacent above the recording unit 22.
The roller 46 is inclined so that the roller 46 side faces downward. A roller 50 is arranged on the conveyor 42 so as to face the roller 46. The printing plate 12 sent to the conveyor 42 is conveyed on the conveyor belt 48 and
6 and 50.

As shown in FIGS. 1 and 2, the recording unit 2
2, a rotary drum 54 and a recording head 56 are mounted on a gantry 52. Further, a puncher 58 is disposed above the rotating drum 54, and the transport conveyor 42 holds the printing plate 12 between the rollers 46 and 50, and inserts the leading end of the printing plate 12 into the mouth opening 60 of the puncher 58. Hold. When the leading end of the printing plate 12 is inserted into the mouth opening 60, the puncher 58 punches out a positioning notch at a predetermined position of the leading end of the printing plate 12.

When the notch is formed in the printing plate 12, the transport conveyor 42, together with the transport belt 48,
50 is driven in reverse, and the leading end of the printing plate 12 is
8 is pulled out from the mouthpiece 60. Also, the conveyor 42
Is provided with a swinging means (not shown), and the swinging means moves the roller 46 side around the roller 44 side so as to approach the rotating drum 54 of the recording unit 22. Thereby, the printing plate 12 on the transport belt 48 is
The leading end is directed to a predetermined position on the outer peripheral surface of the rotating drum 54, and is transported on the transport belt 48 toward the rotating drum 54.

The rotating drum 54 is rotated by a driving means (not shown) in the mounting exposure direction of the printing plate 12 (arrow B direction) and the direction of removing the printing plate 12 opposite to the mounting exposure direction (arrow C direction). .

As shown in FIG. 2, a tip end chuck 62 is attached to a rotating drum 54 provided in the recording section 22 at a predetermined position on the outer peripheral surface as a fixing device. When the printing plate 12 is mounted on the rotating drum 54, first, the tip chuck 62 stops the rotating drum 54 at a position (printing plate mounting position) opposed to the leading end of the printing plate 12 fed by the conveyor 42.

The recording section 22 is provided with a mounting cam 64 as one of fixing releasing means facing the tip chuck 62 at the printing plate mounting position. When the mounting cam 64 rotates and one end side is pressed, the tip chuck 62
The printing plate 12 can be inserted between the rotating drum 54 and the peripheral surface thereof. In the recording unit 22, with the leading end of the printing plate 12 inserted between the leading end chuck 62 and the rotary drum 54, the mounting cam 64 is rotated to release the pressing on the leading end chuck 62, and thereby the printing plate 12 is released. The tip of the tip chuck 62
And the peripheral surface of the rotating drum 54. At this time, the printing plate 12 is positioned with respect to the rotary drum 54 by inserting a positioning pin (not shown) projecting from a predetermined position of the rotary drum 54 into a notch formed by the puncher 58. Is done.

In the recording section 22, when the leading end of the printing plate 12 is fixed to the rotating drum 54, the rotating drum 54 is rotated in the mounting exposure direction. As a result, the printing plate 12 sent from the conveyor 42 is wound around the peripheral surface of the rotating drum 54.

In the vicinity of the peripheral surface of the rotary drum 54, the squeeze roller 6 is located downstream of the printing plate mounting position in the mounting exposure direction.
6 are arranged. The squeeze roller 66 moves toward the rotating drum 54 so that the rotating drum 54
The printing plate 12 to be wound around is pressed toward the rotating drum 54 to bring the printing plate 12 into close contact with the peripheral surface of the rotating drum 54.

The recording section 22 includes a squeeze roller 6.
A rear end chuck attaching / detaching unit 68 is provided near the upstream side of the rotary drum 54 in the mounting exposure direction with respect to 6, and a removal cam 70 is disposed near the downstream side in the mounting exposure direction as fixing release means. In the rear end chuck attaching / detaching unit 68, a rear end chuck 74 is attached to a front end of a shaft 72 protruding toward the rotating drum 54.

In the recording section 22, the rear end of the printing plate 12 wound around the rotary drum 54 is connected to the rear end chuck attaching / detaching unit 6.
8, the shaft 72 is made to protrude, and the rear end chuck 74 is mounted at a predetermined position on the rotating drum 54. As a result, the rear end chuck 74 sandwiches and holds the rear end of the printing plate 12 with the rotating drum 54.

In the recording unit 22, when the rotating drum 54 holds the leading and trailing ends of the printing plate 12, the squeeze roller 66
Apart. After that, the recording unit 22
The recording head 56 emits a light beam modulated based on image data in synchronism with the rotation of the rotating drum 54 while rotating the drum 4 at a high speed at a predetermined rotation speed. Thus, the printing plate 12 is scanned and exposed based on the image data. Note that a conventionally known configuration can be used for the rotation mechanism and the like of the rotary drum 54, and a detailed description is omitted.

In the recording unit 22, when the scanning exposure on the printing plate 12 is completed, the rotating drum 54 is moved to a position where the rear end chuck 74 holding the rear end of the printing plate 12 faces the rear end chuck attaching / detaching unit 68. The printing plate 12 is temporarily stopped, and the printing plate 12 is
Sandwich. The rear end chuck attaching / detaching unit 68 removes the rear end chuck 74 from the rotary drum 54 when the rear end chuck 74 faces and the rotation of the rotary drum 54 stops.
Thereby, the rear end of the printing plate 12 is opened.

In the recording section 22, when the rear end chuck 74 is removed from the rotary drum 54, the rotary drum 54 is
2. Rotate in the unloading direction.

As shown in FIG. 1, the discharge buffer unit 2
4 is provided above the squeeze roller 66,
As the rotating drum 54 rotates in the direction in which the printing plate 12 is removed, the printing plate 12 is moved from the rear end side to the discharge buffer unit 2.
It is sent out to 4. The rotating drum 54 rotates in the direction in which the printing plate 12 is removed, and stops at the printing plate removal position where the tip chuck 62 faces the removal cam 70. The recording unit 22 presses the tip chuck 62 by rotating the removal cam 70, and
The holding of the leading end of the printing plate 12 between the rotating drum 2 and the rotating drum 54 is released. As a result, the printing plate 12 is
Removed from

On the other hand, the discharge buffer section 24 is provided inside a discharge port 76 formed in the machine casing 14,
A discharge roller 78 is provided. Around the discharge roller 78, a plurality of small rollers (for example, small rollers 80A,
80B, 80C, 80D, 80E) are arranged,
An endless transport belt 82 is wound between these small rollers 80A to 80E. As a result, the discharge roller 78 has a 1/1 between the small roller 80A and the small roller 80E.
The transport belt 82 is wound around in a range of two to three quarters.

The small roller 80A protrudes toward the squeeze roller 66 of the recording unit 22, and the roller 84 is disposed to face the small roller 80A. The printing plate 12 sent from the recording unit 22 is guided between the small rollers 80A and the rollers 84, and is held between the small rollers 80A and the rollers 84.

In the discharge buffer section 24, the discharge rollers 78
Is rotated in the direction in which the printing plate 12 is pulled in (in the direction of arrow D), so that the printing plate 12 sandwiched between the small rollers 80A and the rollers 84 is guided between the discharge roller 78 and the transport belt 82 while being pulled out from the recording unit 22. , Discharge roller 78
, And wound around the discharge roller 78. At this time, in the discharge buffer unit 24, the printing plate 12 wrapped around the discharge roller 78 is firstly held by clamping the leading end of the printing plate 12 (the leading end chuck 62 side in the recording unit 22) between the small rollers 80 </ b> A and the rollers 84. Hold.

On the other hand, as shown by a two-dot chain line in FIG.
In the discharge buffer section 24, the small roller 80A and the roller 84
Moves to a position facing the outlet 76. At this time, the small roller 80A and the roller 84 rotate integrally, so that the leading end of the printing plate 12 is directed to the discharge port 76. The small roller 80B above the small roller 80A moves following the movement of the small roller 80A, and applies a constant tension to the transport belt 82.

In the discharge buffer section 24, when the leading end of the printing plate 12 is directed to the discharge port 76, the discharge roller 78 is moved to the printing plate 12 in a processing device such as an automatic developing device arranged adjacent to the discharge port 76. The printing plate 12 is driven to rotate at a rotation speed corresponding to the conveyance speed of the printing plate 12 in the direction in which the printing plate 12 is sent out (the direction opposite to the direction of arrow D). As a result, the printing plate 12 is sent out from the outlet 76.

A tip chuck 62 is attached to the rotating drum 54 as a fixing device for fixing the printing plate 12 as a sheet as described above.

As shown in FIG.
Is provided with a clamp 100 formed in a strip shape of a predetermined length. The tip chuck 62 includes a plurality of clamps 1.
00 are arranged along the axial direction of the rotating drum 54.

As shown in FIGS. 3 to 5, the clamp 100 is provided with a clamp portion 102 protruding toward the peripheral surface of the rotary drum 54. This clamp part 1
Numeral 02 is formed at the tip end of the rotary drum 54 extending in the circumferential direction from the main body 122 having a rectangular cross section along the circumferential direction of the rotary drum 54.

The clamp 100 includes a clamp 102
Are disposed facing the upstream side in the mounting exposure direction of the rotating drum 54, and the clamp portion 102 and the rotating drum 5
4, the front end of the printing plate 12 wound around the rotating drum 54 is held and fixed.
That is, the tip chuck 62 includes a plurality of clamps 100.
Thereby, the leading end of the printing plate 12 is fixed along the width direction thereof.

The surface of the clamp 100 near the clamp portion 102 and opposite to the clamp portion 102 (FIGS. 3 to 5)
A plurality of concave portions 1 having a substantially rectangular shape
04 is formed. That is, each of the concave portions 104 is provided so as to be deviated toward the clamp portion 102 which is one end side in the width direction of the clamp 100.

As shown in FIGS. 4 and 5, the clamp 100 has legs 10 serving as support shafts in respective recesses 104.
6 are attached. The leg 106 is formed with, for example, a base 108 having a rectangular block shape.
The base 108 is inserted into the rotary drum 54 and fixed.

The leg 106 includes a base portion 108 and a leg portion 110.
As shown in FIG. 5, a support shaft 112 having a smaller diameter protrudes from the leg portion 110. Clamp 10
In the recess 104, a through hole 114 is formed in the recess 104, into which the support shaft 112 of the leg 106 is inserted.

The inner diameter of the through hole 114 is larger than the outer diameter of the support shaft 112, and the leg 106 is connected to the support shaft 1.
12 is inserted into the through hole 114, and a screw 116 is screwed into the tip of the support shaft 112, and attached to the clamp 100. At this time, the clamp 100 and the leg 110 of the leg 106
Between the clamp 100 and the screw 116, a seat plate 118 formed of an elastic body is sandwiched.
8 and a holding plate 120 formed by a flexible member are sandwiched.

As a result, the clamp 100 is
By elastically deforming the support 8 and the holding plate 120, the support plate 112 can swing around a predetermined position (hereinafter, referred to as “support point P _A ”) near the support shaft 112.

On the other hand, as shown in FIG. 5 and FIG.
Is formed on the side opposite to the main body 122, the center of gravity position G is on the side opposite to the clamp portion 102 with the support shaft 112 interposed therebetween. Further, the support shaft 112 is
Of the center of gravity G
It is far away from 12.

As shown in FIGS. 4 to 6, the main body 122 of the clamp 100 is provided with a plurality of biasing legs 124 on the rotating drum 54 side (the lower side of the paper in FIGS. 4 and 5). . Each of the biasing legs 124 is, for example, a leg 1
06 can be provided as a pair.

The biasing leg 124 has a substantially disk-shaped contact plate 126 facing the peripheral surface of the rotary drum 54, and a shaft 128 erected from the contact plate 126 is connected to the main body 122 of the clamp 100. Through hole 13 formed in
0 (see FIG. 5) so as to be movable along the axial direction.

The shaft 128 has a flange 132 at an intermediate portion along the axial direction. Further, the through hole 130 has an enlarged diameter portion 134 formed on the opposite side of the rotary drum 54, and prevents the flange portion 132 from entering the enlarged diameter portion 134 to prevent the shaft 128 from coming off to the rotating drum 54 side. ing.

As shown in FIG. 5 and FIG.
24 includes a backing plate 126 and a clamp 100 (the main body 12).
Between 2), a coil spring 136 is arranged as an urging means (not shown in FIG. 4). The urging leg 124 is urged toward the peripheral surface of the rotary drum 54 by the urging force of the coil spring 136.

The tip chuck 62 has a backing plate 126 in contact with the rotary drum 54, thereby the clamp 1
00 is urged by the coil spring 136 in a direction in which the main body 122 side is separated from the peripheral surface of the rotary drum 54.

The contact plate 126 of the urging leg 124 may be in contact with the outer peripheral surface of the rotary drum 54 when the clamp 100 is attached to a predetermined position of the rotary drum 54. A concave portion may be formed on the peripheral surface of the device, and the concave portion may enter the concave portion.
In addition, each of the backing plate 126 and the clamp 100 includes
A guide ring 138 having an enlarged diameter of the shaft 128 is formed, and the guide ring 138 enters the end of the coil spring 136 to prevent the coil spring 136 from shifting.

The clamp 100 is urged in the direction in which the clamp portion 102 approaches the peripheral surface of the rotary drum 54 by urged by the coil spring 136 on the main body 122 side. With this urging force, the clamping force of the printing plate 12 is applied to the clamp 100 between the clamp part 102 and the rotating drum 54.

Here, in the present embodiment, the rotating drum 5
4 is stopped, the printing plate 12 sandwiched between the clamp unit 102 and the peripheral surface of the rotating drum 54 is
Due to the rigidity of the support, the clamping unit 102
The urging force of the coil spring 136 is reduced so that a clamping force that does not separate from the peripheral surface of the coil spring 4 is applied.

On the other hand, as shown in FIGS. 1 and 2, the recording section 22 is provided with a mounting cam 64 and a detaching cam 70 as fixing release means. As shown in FIG. 6, the mounting cam 64 and the removal cam 70 face the upper surface 140 of the main body 122.

That is, in the recording section 22, when the printing plate 12 is wound around the rotary drum 54, the tip chuck 62
The rotary drum 54 is stopped at a position where the upper surface 140 of the main body 122 of the clamp 100 that forms In the recording unit 22, when removing the printing plate 12 from the rotating drum 54, the main body 122 of the clamp 100 is removed.
Is stopped at a position where the upper surface 140 faces the removal cam 70.

The mounting cam 64 and the detaching cam 70 have a pressing portion 142 protruding, and the pressing portion 142 is rotated (for example, about 90 °) so as to face the upper surface 140 of the clamp 100 (main body 122). , The pressing portion 142 abuts on the upper surface protrusion 140 of the main body 122 and the coil spring 13
6, the main body 122 side of the clamp 100 is pushed down.

The clamp 100 swings by the urging force of the coil spring 136 when the mounting cam 64 and the removal cam 70 are rotated back and the pressing portion 142 is separated from the upper surface 140 of the main body 122. The side 122 is separated from the peripheral surface of the rotating drum 54.

When the main body 122 is pressed by the mounting cam 64 or the removing cam 70, the clamp 100 swings in a direction in which the clamp portion 102 separates from the peripheral surface of the rotary drum 54 against the urging force of the coil spring 136. I do. The swing of the clamp 100 allows the leading end of the printing plate 12 to be inserted and removed between the clamp unit 102 and the rotating drum 54. The mounting cam 64 and the detaching cam 70
May be provided so as to face one or more of each of the plurality of clamps 100, and may be provided in the axial direction of the rotary drum 54 (elongated along the longitudinal direction of the clamps 100, You may make it oppose.

On the other hand, as shown in FIG. 6, the clamp 10 of the tip chuck 62 attached to the rotary drum 54
0 is the pressing force F by the mounting cam 64 and the removal cam 70.
₁ , the urging force F ₂ by the coil spring 136, the clamp 10
Clamping force to the printing plate 12 by 2 F ₃ and the rotary drum 54
There centrifugal force F ₄ acts when the rotation. In FIG. 6, only the approximate directions of the pressing force F ₁ , the urging force F ₂ , the clamping force F ₃ and the centrifugal force F ₄ are shown by arrows.

[0070] biasing force F ₂ of the centrifugal force F ₄ and the coil spring 138, the center of gravity of the clamp 100 positions G and coil spring 1
Each of the biasing center P _B by 36, rotating drum 54
In the direction away from the peripheral surface of the printing plate 12, the clamping force F ₃ by the clamp portion 102 is
Acting toward the axial direction of the rotary drum 54 in the contact center P _C to. The pressing force F ₁ by mounting the cam 64 and the detaching cam 70 is mounted a cam 64, act toward the contact center P _D to the rotating drum 54 to the pressing portion 142 of the detaching cam 70. The pressing portion 142 of the mounting cam 64 and the detaching cam 70 abuts on the upper surface 140 of the clamp 100,
Thereby, even if the clamp 100 rotates, the pressing portion 14
Contact position of 2 is the tip portion of the pressing portion 142, FIG. 6 illustrates the distal end of the pressing portion 142 as a contact center P _D.

Here, in the clamp 100 applied to the present embodiment, the clamp section 1 is moved from the main body 122 having a rectangular cross section.
02 is projected to, by providing the fulcrum P _A in the vicinity of the clamping portion 102, the vertical distance L ₁ with respect to the centrifugal force F ₄ from the fulcrum P _A, the vertical distance L ₂ for the urging force F ₂ of the coil spring 136, he mounted cam When the vertical distance L _{3 with} respect to the pressing force F ₁ of the mounting cam 64 and the removal cam 70 and the vertical distance L ₄ with respect to the clamping force F ₃ of the clamp portion 102, the vertical distance L ₁ is set to be longer than the vertical distance L ₄ . (L ₁ >
L ₄ ).

As a result, when the rotary drum 54 is rotated, the centrifugal force F ₄ is increased, and is changed to the clamping force F ₃ when the clamp section 102 clamps the printing plate 12 with the rotating drum 54. Like that.

In the clamp 100, the vertical distance L ₂
Is longer than the vertical distance L ₄ (L ₂ > L ₄ ). Therefore, even if the urging force F ₂ of the coil spring 136 is small,
Predetermined clamping force F ₃ is to be obtained.

Further, in the clamp 100, the mounting cam 6
4 and the contact center P _D of the removal cam 70 is set near the urging center P _B (L ₃ ≦ L ₂ ). That is, in the clamp 100, the vertical distances L ₁ , L ₂ , L ₃ , and L ₄ are L ₄ <
L ₁ <L ₃ ≦ L ₂ . In the present invention,
It is sufficient that at least L ₄ <L ₁ , L ₃ ≦ L ₂ , the vertical distance L ₄ is the smallest, and the vertical distance L ₂ is the largest.

Thus, the urging force F of the coil spring 136 is
₂ from a slightly large pressing force F _1, it is possible to fixed and unpinning the rotary drum 54 of the printing plate 12 by the clamp 100, by reducing the biasing force F ₂ of the coil spring 136, also the pressing force F ₁ They are relatively small.

The operation of the present embodiment will be described below.

In the image exposure apparatus 10, image data to be exposed on the printing plate 12 is input, and the printing plate 12 for performing image exposure is input.
When the size and the number of exposures are set and the start of image exposure is instructed, the image exposure processing on the printing plate 12 is started. Note that these processes may be performed by providing an operation panel in the image exposure apparatus 10 and instructing the same by operating a switch on the operation panel. A signal from an image processing apparatus or the like that outputs image data to the image exposure apparatus 10 may be used. May be used to instruct the image exposure apparatus 10 to start processing.

When the start of the processing is instructed, the image exposing apparatus 10 moves the sheet-feeding unit 30 together with the reversing unit 28 to a position corresponding to the cassette 16 accommodating the printing plate 12 of the designated size. The suction plate 38 sucks and removes the printing plate 12 in the corresponding cassette 16, and sends the printing plate 12 between the reversing roller 32 of the reversing unit 28 and the transport belt 36. As a result, the printing plate 12 is moved
2 and the conveyor belt 36 to be conveyed.
Sent to

The transport conveyor 42 inserts the leading end of the printing plate 12 into the opening 60 of the puncher 58, and the puncher 58 forms a positioning notch at a predetermined position on the printing plate 12. When the notch is formed in the printing plate 12, the conveyor 42 pulls out the printing plate 12 from the mouth 60 of the puncher 58 and sends out the printing plate 12 toward the peripheral surface of the rotating drum 54.

In the recording unit 22, when the leading end of the printing plate 12 is held on the rotating drum 54 by the tip chuck 62, the printing plate 12 is wound around the rotating drum 54 while being squeezed by the squeeze roller 66, and the trailing end of the printing plate 12 is Is held on the rotating drum 54 by the rear end chuck 74.

Thereafter, in the recording section 22, the rotating drum 54
The recording plate 56 irradiates the printing plate 12 with a light beam based on image data while rotating the printing plate 12 at a high speed.
Is exposed by scanning. When the scanning exposure of the printing plate 12 is completed,
The trailing end chuck 74 is removed from the rotating drum 54, and the printing plate 12 is sent to the discharge buffer unit 24.

In the discharge buffer section 24, after the printing plate 12 is nipped and conveyed by the small rollers 80A and the rollers 84 and wound around the discharge rollers 78, the small plates 80A and the rollers 84
Is discharged from the outlet 76 at a predetermined transport speed so as to face the outlet 76.

On the other hand, the rotary drum 54 is provided with a front end chuck 62 and a rear end chuck 74 is mounted thereon. When the printing plate 12 wound around the rotating drum 54 is fed from the conveyor 42 to the recording unit 22, the leading end is fixed to the rotating drum 54 by the leading end chuck 62 and wound around the rotating drum 54. In the recording unit 22, the printing plate 1 is mounted by attaching a rear end chuck 74 to the rotating drum 54 in accordance with the rear end position of the printing plate 12 wound around the rotating drum 54.
2 is fixed to the rotating drum 54 at its rear end.

In the recording section 22, the leading end and the trailing end of the printing plate 12 wound around the rotating drum 54 are held at the leading end chuck 62.
Then, when fixed by the rear end chuck 74, the rotating drum 54 is rotated at a high speed in the mounting exposure direction.

By the way, the clamp 1 of the tip chuck 62
00 is mounted on the rotating drum 54 supported by the legs 106. In addition, this clamp 100
A biasing leg 124 is attached to the extending portion 122, and the clamp portion 102 is biased toward the peripheral surface of the rotary drum 54 by the biasing force of a coil spring 136 provided on the biasing leg 124, and The printing plate 12 can be clamped and fixed to the drum 54.

Here, the clamp 100 is arranged such that the vertical distance L ₂ with respect to the urging force F ₂ from the fulcrum P _A is
It is longer than the vertical distance L ₄ for clamping force F ₃ acting. For this, the clamp 100, even small urging force F _2, the desired clamping force F ₃ is obtained. This allows
The clamp 100 can securely fix the printing plate 12 to the rotary drum 54 without using a strong coil spring 136 that can provide a large urging force. The coil spring 13
When 6 a biasing force F ₂ of the larger, it becomes necessary to strengthen or increase the clamp 100 in accordance therewith, but resulting in an increase in weight of the clamp 100, the coil spring 1
Since the urging force of the clamp 36 can be reduced, such an increase in the weight of the clamp 100 can be prevented. That is,
The weight and compactness of the clamp 100 can be reduced.

Therefore, the printing plate 12 is moved to the rotating drum 54
The rotating drum 54 and the clamp 1
It is not necessary to increase the weight of 00, and it is possible to prevent a large load from being applied to the driving unit for driving the rotating drum 54, and to prevent the rotating drum 54 from becoming unbalanced. .

On the other hand, the clamp 100 of the tip chuck 62
The mounting cam 64 or the removal cam 70 is
2 against the upper surface 140 of the main body 122 of the clamp 100, and against the urging force F ₂ of the coil spring 136, the main body 12
By pressing 2, rotates about a fulcrum P _A, to separate the clamping portion 102 from the circumferential surface of the rotary drum 54.

That is, the clamp 100 is mounted on the mounting cam 6
By body 122 side is pressed toward the rotating drum 54 by 4 or removal cam 70 rotates about the fulcrum P _A. By the rotation of the clamp 100, the fulcrum P _A
The clamp portion 102 provided on the opposite side of the main body 122 across the is separated from the peripheral surface of the rotary drum 54, and the printing plate 12 can be inserted and removed between the clamp portion 102 and the peripheral surface of the rotary drum 54. Gaps occur.

Thus, in the recording section 22, the leading end of the printing plate 12 can be inserted between the clamp section 102 and the peripheral surface of the rotary drum 54, and the leading end of the printing plate 12 is pressed and fixed by the clamp section 102. In this case, the pressing of the printing plate 12 is released, and the printing plate 12 can be removed from the peripheral surface of the rotating drum 54. In other words, the mounting cam 64 and the removal cam 70 formed by the eccentric cam can easily fix and release the leading end of the printing plate 12.

At this time, the urging force F _{2 of the} coil spring 136
, The mounting cam 64 and the detaching cam 7
Contact center P _D 0 is, the fulcrum P _A from the vicinity or biased center P _B of the urging center P _B of the clamp 100 by a coil spring 136
Closer to also as long obtain a relatively small pressing force F _1, the fixed and unlocking of the printing plate 12 becomes possible.

That is, the mounting cam 64 and the detaching cam 7
Since requires 0 a small pressing force F ₁ by mounting the cam 64
In addition, it is possible to substantially improve the durability of the mounting cam 64 and the removal cam 70 without imposing a large burden on the rotating shaft of the removal cam 70 and the driving means for driving the mounting cam 64 and the removal cam 70.

[0093] Further, if the urging force F ₂ of the coil spring 136 is large, in order to reduce the pressing force F ₁ has to the vertical distance L ₃ greater than the vertical distance L _2, the clamp 100 for this purpose Becomes large. In contrast, in the clamp 100, since the vertical distance L ₃ can be smaller than the vertical distance L _2, together with the compact becomes possible, while reducing the load reduction of mounting cams 64 and removal cam 70, reliable printing plate 12 Can be fixed and released.

[0094] In this embodiment, although the vertical distance L ₃ is shorter than the vertical distance L ₂ (L ₃ <L _2), the vertical distance L ₃ may be the same as the vertical distance L ₂ (L ₃ =
L _2). That is, it is sufficient that L ₃ ≦ L ₂ .

[0095] On the other hand, the centrifugal force F ₄ acts on each of the clamp 100 by rotating the rotary drum 54. The centrifugal force F ₄ is increased by the rotating drum 54 rotates at a high speed. Clamp 100, so as to provide a fulcrum P _A in the vicinity of the clamping portion 102 projecting from the main body 122, the center of gravity position G is, the clamp portion 102 across the fulcrum P _A
And it becomes opposite, and the vertical distance L ₁ is set to be larger than the vertical distance _{L 4 (L 1> L 4} ).

[0096] Thus, the clamp 100 can be small and light, it is possible to produce a large clamping force F ₃ to the clamp unit 102 when the rotary drum 54 is rotated,
The leading end of the printing plate 12 can be reliably fixed to the rotating drum 54 without the clamping of the printing plate 12 by the clamp 100 being loosened.

Therefore, even if the clamp 100 is reduced in size and weight, the leading end chuck 62 applied to the present embodiment can prevent the printing plate 1 from rotating when the rotating drum 54 rotates at high speed.
2 can be reliably fixed at a predetermined position on the rotating drum 54.

The rotating drum 54 to which such a clamp 100 is attached as the tip chuck 62 does not lose its rotational balance even when rotated at high speed. Therefore, the image exposure apparatus 10 to which the rotating drum 54 is attached does not become large, and the printing plate 12 wound around the rotating drum 54 is placed at an appropriate position.
An image can be formed.

Note that the present embodiment described above does not limit the configuration of the present invention. In the present embodiment,
Although the present invention is applied to the front end chuck 62, it may be applied to the rear end chuck 70. In the present embodiment, the printing plate 12 is used as a sheet member, and the image exposure apparatus 10 that performs scanning exposure of an image on the printing plate 12 has been described as an example. However, the sheet member is not limited to the printing plate 12, Various photosensitive materials such as film and photographic paper can be applied, and the present invention can be applied to apparatuses having various configurations provided with a rotating drum that rotates by winding the photosensitive material.

[0100]

As described above, according to the present invention, the weight and size of the clamp can be reduced, and the sheet can be securely fixed to the rotating drum. Therefore, an excellent effect is obtained in that the rotational balance is not lost on the rotating drum that rotates at a high speed by winding the sheet body, and the device provided with the rotating drum is not increased in size. .

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an image exposure apparatus to which the present invention is applied.

FIG. 2 is a schematic configuration diagram illustrating a recording unit of the image exposure apparatus.

FIG. 3 is a schematic perspective view showing a tip chuck to which the present invention is applied.

FIG. 4 is a schematic perspective view showing a main part of the tip chuck.

FIG. 5 is a schematic sectional view along a width direction of a clamp showing a main part of the tip chuck.

FIG. 6 is a schematic view of a tip chuck showing a centrifugal force generated in a clamp and a clamping force generated in a clamp portion when a rotary drum is rotated.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Image exposure apparatus 12 Printing plate (sheet body) 22 Recording part 54 Rotating drum 62 Tip chuck (fixing device of sheet body) 64 Mounting cam (fixing releasing means) 70 Removal cam (fixing releasing means) 100 Clamp 102 Clamping part 106 Leg 112 Support shaft 122 Main body 124 Urging leg 136 Coil spring (urging means)

Claims (1)

[Claims] 1. A sheet fixing device which is provided on a rotating drum which rotates with a sheet wound around a peripheral surface, and which fixes a peripheral portion of the sheet by sandwiching the peripheral portion between the sheet and the rotating drum. A clamp portion is provided on one end side of the rotary drum along the circumferential direction, the clamp portion being opposed to the peripheral surface of the rotary drum and sandwiching the sheet body with the peripheral surface of the rotary drum. And a clamp biased to the other end side along the circumferential direction of the rotating drum; and the clamp can swing in the direction of contact and separation of the clamp from the circumferential surface of the rotating drum near the clamp. A supporting shaft supported by the rotating drum, and a rotating portion of the rotating drum such that the clamp portion for holding the sheet body between the rotating drum and the rotating drum in a stopped state of the rotating drum does not separate from a circumferential surface of the rotating drum. Along the direction Urging means for urging the other end of the clamp; and when the rotary drum stops at a predetermined position, between the position supported by the support shaft and the position energized by the urging means. And a fixing release means for pressing the clamp against the urging force of the above to swing the clamp in a direction in which the clamp part separates from the peripheral surface of the rotary drum.