JP2003276899A - Sheet material retention device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet material retention device capable of reducing unevenness in press force of a sheet material by a clamp part, and preventing the floating of the sheet material from a rotation drum. <P>SOLUTION: In a tip chuck unit 10, a plurality of tip chucks 26 turnably supported by a support shaft 48 parallel to a shaft of the rotation drum 12 respectively have the clamp parts 52 pinching a printing plate between the rotation drum 12 and the clamp parts 52 on one side of the support shaft 48, and have weight members 58 capable of changing gravity center positions of the tip chucks 26 according to screwing amounts of male parts 60 on the other side. When the rotation drum 12 rotates, centrifugal force of the weight member 58 or the like is converted into pinching force of the printing plate by the clamp part 52. A width of each the tip chuck 26 and an interval of the adjacent tip chucks 26 are set to be smaller than a non-pinching distance allowing maintenance of a closely contact state of the printing plate with the rotation drum 12, between pinching points. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet material holding device for holding an end portion of a sheet material in a winding direction between the sheet material and a peripheral surface of the rotary drum when or after the sheet material is wound around the rotary drum.

[0002]

2. Description of the Related Art A sheet-shaped recording material (sheet material), particularly a printing plate having a photosensitive layer (emulsion surface) provided on a support is used, and the printing plate is wound around a peripheral surface of a rotary drum at high speed. A technique for recording an image on the photosensitive layer by irradiating the photosensitive layer of the printing plate with a laser beam by a recording head that moves (sub-scan) along the axial direction of the rotating drum while rotating (main scanning). A printing plate exposure apparatus) has been developed. With such a technique, it is possible to quickly record an image on a printing plate.

In recording an image on a printing plate, the leading end of the printing plate supplied from the plate feeding unit in the winding direction is held by a leading end chuck of a leading end chuck unit which is a sheet material holding device attached to a rotating drum. Further, in this state, the rotary drum is rotated at a low speed to wind the printing plate around the rotary drum, and the rear end of the printing plate wound around the rotary drum is held by the rear end chuck of the rear end chuck unit which is a sheet material holding device. It is supposed to do.

The leading end chuck is attached to a predetermined position of the rotating drum so that a plurality of printing plates having different vertical and horizontal sizes can be wound around the rotating drum, and the trailing end chuck is provided for printing plates of different sizes. The rotary drum is movable or attachable / detachable to the circumferential position according to the rear end position.

With respect to such a sheet material holding device, an example of the tip chuck unit will be described with reference to FIG. As shown in this figure, the tip chuck unit 100 is
A plurality of tip chucks 104, which are attached at predetermined positions on the outer peripheral portion of the rotating drum 102 and are arranged in a line along the rotation axis direction of the rotating drum 102, are provided.

Each tip chuck 104 is rotated (swinged) around the support shaft 106 by a support shaft 106 parallel to the rotation axis direction and a base block 108 that supports the support shaft 106 and is fixed to the rotating drum 102. Supported). Further, in each of the tip chucks 104, a portion provided so as to project toward the outer peripheral surface 102A side of the rotary drum 102 over the entire width at the end portion on the printing plate supply side is the clamp portion 1.
04A, the clamp portion 104A with the support shaft 106 interposed therebetween.
The portion on the side opposite to is the action portion 104B. A spring (not shown) is engaged with the action portion 104B, and the clamp portion 104A is moved to the outer peripheral surface 102A by the urging force of the spring.
Is urged in the direction of abutting against.

When the acting portion 104B is pressed toward the outer peripheral surface 102A by a chuck opening / closing unit (not shown), the tip chuck 104 is rotated against the biasing force, and the clamp portion 104A is separated from the outer peripheral surface 102A. The printing plate is ready to be received. In this state, the tip of the printing plate is inserted between the outer peripheral surface 102A and the clamp portion 104A,
After that, when the chuck opening / closing unit releases the pressed state of the action portion 104B, the leading end of the printing plate is sandwiched between the outer peripheral surface 102A and the clamp portion 104A by the biasing force.

Further, the tip chuck 104 has a working portion 1
It has a weight member (not shown) fixed to 04B, and its center of gravity is located closer to the action portion 104B than the support shaft 106. As a result, when the rotary drum 102 rotates, the centrifugal force in the direction in which the acting portion 104B side separates from the rotary shaft of the rotary drum 102 causes the pressing force of the printing plate by the clamp portion 104A, that is, between the clamp portion 104A and the outer peripheral surface 102A. It is converted into the clamping force of the printing plate, and the leading edge of the printing plate is more firmly clamped.

The interval between the tip chucks 104 (width of the base block 108) is about 20 mm to 30 mm. By setting in this way, even if there is a portion where the printing plate is not sandwiched between the adjacent front end chucks 104, the outer peripheral surface 10 of the printing plate sandwiched on both sides thereof is provided.
It can be wrapped around (attached to, and maintained in the attached state) without floating on 2A.

[0010]

However, in the conventional tip chuck unit 100 as described above, the width of the clamp portion 104A (the dimension in the rotation axis direction) over the entire width of the tip chuck 104 is as large as about 100 mm, There is a problem that the pressing force distribution in the width direction of the clamp portion 104A tends to vary when the printing plate is clamped due to the processing accuracy, the mounting accuracy, the deformation, and the like of the clamp portion 104A.

Specifically, only both ends in the width direction of the clamp portion 104A are likely to be pressing portions (pressing points), and the pressing force on the printing plate does not act on the central portion in the width direction of the clamp portion 104A (the pressing force is small). (Part) In the vicinity of the non-sandwiched part, the printing plate floats up from the outer peripheral surface 102A of the rotary drum 102.

Therefore, a so-called crown shape is adopted in which the central portion in the width direction of the clamp portion 104A is more convex than both end portions,
A configuration in which a substantially uniform pressing force is applied over the entire width of the clamp part 104A is conceivable, but setting of such a shape promotes the above-mentioned variation in the pressing force when an error occurs, so that the clamp part 104A (tip chuck ) Processing accuracy,
It is difficult to realize because it requires further improvement in mounting accuracy and rigidity. The same applies to the case where the clamp portion 104A is formed to be uneven along the width direction and the pressing portions are provided at a plurality of positions in the width direction.

In consideration of the above facts, an object of the present invention is to obtain a sheet material holding device capable of reducing the variation of the pressing force of the sheet material by the clamp portion and preventing the sheet material from floating from the rotary drum. is there.

[0014]

In order to achieve the above-mentioned object, a sheet material holding device according to the invention of claim 1 winds the sheet material between the outer peripheral surface of a rotary drum around which the sheet material is wound. A sheet material holding device for sandwiching end portions in a direction, each of which is rotatably supported around an axis parallel to the rotation axis of the rotary drum,
A clamping position for clamping the sheet material with the outer peripheral surface by the pivoting of the pivoting members, and a releasing position for releasing the clamping. And a clamp portion capable of taking the position, and provided on the other side with respect to the rotation center of the plurality of rotation members,
The clamp includes: a centrifugal force generated by the rotation of the rotary drum, which is converted by the rotating member into a clamping force of the sheet material in the clamp part, and the clamping force is adjustable. Both the axial width dimension of the section and the interval between the adjacent clamp sections are set to be equal to or less than the maximum value of the non-clamping distance capable of maintaining the close contact state of the sheet material to the rotating drum between the clamping points. , Is characterized.

In the sheet material holding device according to the first aspect, when the end portion of the sheet material is inserted between the clamp portion and the outer peripheral surface of the rotary drum when the clamp portion is located at the release position, the sheet material holding device is rotated. The moving member rotates to move the clamp portion to the holding position. When the rotary drum is rotated around the rotation axis in this state, the centrifugal force of the clamping force imparting portion causes the rotating member to press the sheet material by the clamp portion, that is, the sheet between the clamp portion and the outer peripheral surface. Converted to the clamping force of the material. As a result, the rotary drum rotates while holding the sheet material with a sufficient clamping force.

Here, since the clamping force (pressing force) by each clamp portion can be adjusted to be substantially constant by the clamping force applying means, the variation of the clamping force among the clamp portions can be suppressed within the allowable range. can do.

Further, the interval between the respective clamp portions is set to be equal to or less than the maximum value (hereinafter referred to as a reference value) of the non-sandwiching distance which can maintain the close contact state of the sheet material to the rotating drum between the sandwiching points. The portion of the sheet material that is located between the clamp portions and is not sandwiched is in close contact with the outer peripheral surface of the rotating drum, and the floating does not occur.

Further, since the width dimension of each clamp portion is not more than the above-mentioned reference value, only the both widthwise end portions become pressing (holding) portions due to processing accuracy, mounting accuracy, deformation, etc. Even so, the non-sandwiching distance of the sheet material is equal to or less than the above-mentioned reference value, and the portion of the sheet material in the center portion in the width direction is also prevented from floating.

As described above, in the sheet material holding device according to the first aspect, it is possible to reduce the variation in the pressing force of the sheet material by the clamp portion and prevent the sheet material from floating from the rotary drum. That is, the sheet material can be sandwiched with an appropriate pressing force distribution without floating, and can be held on the rotating drum.

The above-mentioned reference value is set according to the diameter and rotation speed of the rotating drum and the characteristics of the sheet material (strength of the waist determined by the material and thickness, etc.). When the sheet material holding device of this configuration is applied to the printing plate exposing device, it is possible to adopt the conventional maximum value of the facing distance between the clamp portions of 30 mm.

According to a second aspect of the present invention, there is provided the sheet material holding device according to the first aspect, wherein the width dimension of the clamp portions is set smaller than the distance between the clamp portions. It has a feature.

In order to reduce the variation of the pressing force in the width direction, the width of the clamp portion is preferably as small as possible without impairing the workability and rigidity thereof. However, in the sheet material holding device according to claim 2, Since the width of the clamp portions is smaller than the interval between the clamp portions (that is, the maximum value of the non-holding distance), the variation in the pressing force is further reduced.
Further, since the interval between the clamp portions is larger than the width of the clamp portions, the number of clamp portions is not unnecessarily (unnecessarily) increased.

That is, in the sheet material holding device according to the second aspect of the present invention, the distribution of the appropriate pressing force for the sheet material is suppressed while suppressing an increase in the number of clamp portions (that is, the entire rotating member including the holding force applying portion). It can be clamped and held on the rotating drum without floating. Further, since the increase in the number of parts is suppressed, the rotation moment when the rotating drum rotates can be reduced.

According to a third aspect of the present invention, there is provided the sheet material holding device according to the second aspect, wherein the clamp portion is tapered toward a portion for holding the sheet material. It has a feature.

In the sheet material holding device according to the third aspect of the present invention, since the clamp portion is formed so as to taper toward the portion for sandwiching the sheet material, the strength of the rotating member provided with the clamp portion is maintained. The width of the clamp can be set small.
Further, since the clamp portion is formed in a tapered shape, in other words, since the clamp portion is continuously reduced in width from the rotating member side,
The width can be reduced while ensuring its rigidity.

The tapered shape includes, for example, a trapezoidal shape in cross section, a taper shape such as a triangle, and a curved shape such as an arc shape in cross section.

A sheet material holding device according to a fourth aspect of the present invention is the sheet material holding device according to any one of the first to third aspects, wherein the clamping force applying portion is the other of the rotating members. A weight member connected to the side, and clamping force adjusting means provided between the weight member and the rotating member and capable of changing the fixed position of the weight member. It has a feature.

The gripping force applying portion according to any one of claims 1 to 3 is formed integrally with the rotating member (the center of rotation is displaced from the center of gravity) or fixed to the rotating member. It is possible to adjust the clamping force by scraping off a part of the weight. However, in the sheet material holding device according to claim 4, the fixing position of the weight member constituting the clamping force applying portion with respect to the rotating member is the clamping force adjusting means. It is variable by. That is, since the gripping force adjusting means can change the position of the center of gravity of the portion that rotates together with the rotating member to adjust the gripping force of the sheet material for each clamp portion, the gripping force for each clamp portion ( The pressing force) can be adjusted to be substantially constant.

Further, when the weight member is scraped off, it is difficult to readjust the holding force while maintaining the predetermined holding force. However, by providing the holding force adjusting means, the predetermined holding force can be maintained. It is also possible to adjust the clamping force again. Furthermore, for example, it is possible to increase or decrease the clamping force according to the rotation speed of the rotary drum or the like.

A sheet material holding device according to a fifth aspect of the present invention is the sheet material holding device according to the fourth aspect, wherein the holding force adjusting means is provided on one of the weight member and the rotating member. It is characterized in that it has a male screw portion and a female screw portion provided on the other side and screwed into the male screw portion.

In the sheet material holding device according to the fifth aspect, when the male screw portion and the female screw portion are deeply screwed together, the weight member comes close to the turning member and the center of gravity comes close to the turning center of the turning member. . On the other hand, when the male screw part and the female screw part are shallowly screwed together, the weight member is separated from the rotating member, and the center of gravity is separated from the rotation center of the rotating member. That is, the clamping force of the clamp part can be adjusted according to the screwing amount of the male screw part and the female screw part.

Here, since the clamping force is adjusted by screwing the male screw portion and the female screw portion, it is easy to finely adjust the clamping force, and the clamping force (pressing force) of the sheet material varies among the clamp portions. Can be further reduced. Further, the clamping force adjusting means is realized with an extremely simple structure.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION A tip chuck unit 10 as a sheet material holding device according to an embodiment of the present invention will be described. First, a schematic configuration of an exposure unit 14 of a printing plate automatic exposure device as an image recording apparatus having a rotary drum 12 to which the tip chuck unit 10 is applied will be described, and then the rotary drum 12 and the tip chuck unit 10 will be described. And

FIG. 6 shows a schematic structure of the exposure unit 14 and the transport guide unit 18 that transports the printing plate 16 to the exposure unit 14. As shown in this figure, the exposure unit 14
Includes a rotary drum 12 that holds a printing plate 16 as a sheet material wound around an outer peripheral surface thereof. The printing plate 16 is guided by a conveyance guide unit 18 and is tangential to the rotary drum 12. It is supposed to be sent from.

The transport guide unit 18 is used for the plate feed guide 2
0 and the plate discharge guide 22. The relative position relationship between the plate feed guide 20 and the plate discharge guide 22 of the transport guide unit 18 is a horizontal V shape, and the structure is such that the plate feed guide 20 and the plate discharge guide 22 rotate in the vertical direction on the paper surface of FIG. By this rotation, the plate supply guide 20 or the plate discharge guide 22 is selectively made to correspond to the puncher 24 arranged near the rotary drum 12 or the transport guide unit 18 (the rotary drum 1
2 can be arranged tangentially).

The puncher 24 is the printing plate 1 sent in.
A notch for positioning is formed at the tip of 6. Then, in the exposure unit 14, first, the printing plate 16
Is guided by the plate feeding guide 20 and fed into the puncher 24, and the puncher 24 forms a notch for positioning at the tip thereof. Further, after the processing by the puncher 24, the printing plate 16 is once returned to the plate feed guide 20, and when the transport guide unit 18 is rotated, the printing plate 16 is moved to a position corresponding to the rotary drum 12.

The rotary drum 12 is driven by a driving means (not shown) so as to be in the mounting exposure direction of the printing plate 16 (direction shown by arrow A in FIG. 6) and in the direction opposite to the mounting exposure direction.
It is configured to be rotated in the removing direction (direction indicated by arrow B in FIG. 6). In addition, when the arrow A and the arrow B are shown in the other drawings, they indicate the mounting exposure direction and the removal direction, respectively.

The rotary drum 12 which constitutes the exposure section 14
The tip chuck unit 1 at a predetermined position on the outer peripheral surface.
A tip chuck 26, which constitutes 0, is attached.
In the exposure unit 14, when the printing plate 16 is mounted on the rotating drum 12, first, the leading end chuck 26 faces the leading end of the printing plate 16 fed by the plate feed guide 20 of the transport guide unit 18 (the printing plate 16). The rotating drum 12 is stopped at the mounting position).

In the exposure section 14, a chuck opening / closing unit 28 is provided so as to face the tip chuck 26 at the printing plate mounting position.
Is provided. The tip chuck 26 is in a receiving state in which the printing plate 16 can be inserted between the tip chuck 26 and the outer peripheral surface of the rotating drum 12 when the telescopic rod 28A of the chuck opening / closing unit 28 extends and one end side is pressed. In this state, the printing plate 16 is guided and conveyed by the plate feed guide 20 between the leading end chuck 26 and the outer peripheral surface of the rotating drum 12, and the leading end of the printing plate 16 is projected on the rotating drum 12 at a predetermined position. The printing plate 16 is positioned by being abutted against a positioning pin (not shown).

In this state, the telescopic rod 28A of the chuck opening / closing unit 28 is pulled back to pull the tip chuck 26
When the pressure is released, the tip of the printing plate 16 (one end in the winding direction) is clamped and held between the tip chuck 26 and the peripheral surface of the rotary drum 12. The detailed configuration of the tip chuck unit 10 having the tip chuck 26 will be described later.

When the front end of the printing plate 16 is fixed to the rotary drum 12, the exposure unit 14 rotates the rotary drum 12 in the mounting exposure direction. As a result, the printing plate 16 fed from the plate supply guide 20 of the transport guide unit 18 is wound around the outer peripheral surface of the rotary drum 12.

Further, a squeeze roller 30 is arranged downstream of the printing plate mounting position (chuck opening / closing unit) near the outer peripheral surface of the rotary drum 12 in the mounting exposure direction. This squeeze roller 30 is used for the rotary drum 12.
When the printing plate 16 is wound around the outer peripheral surface of the rotating drum 12, the printing plate 16 is wound around the rotating drum 12 by moving toward the outer peripheral surface. The printing plate 16 is pressed against the rotary drum 12 and brought into close contact with the peripheral surface of the rotary drum 12.

The exposure unit 14 includes a squeeze roller 3
A rear end chuck attachment / detachment unit 32 is arranged near the upstream side of the rotary drum 12 in the mounting exposure direction with respect to zero. The trailing end chuck attachment / detachment unit 32 includes a trailing end chuck 36 attached to the tip of a shaft 34 protruding toward the rotary drum 12.

In the exposure section 14, the trailing edge of the printing plate 16 wound around the rotary drum 12 is the trailing edge chuck attaching / detaching unit 3
When reaching the position opposite to 2, the rear end chuck attaching / detaching unit 32 causes the shaft 34 to project, and the rear end chuck 36 is mounted at a predetermined position on the rotary drum 12. As a result, the rear end chuck 36 moves the rotary drum 12
The rear end of the printing plate 16 is sandwiched and held between and.

In the exposure unit 14, the squeeze roller 30 is separated when the front and rear ends of the printing plate 16 are held on the rotary drum 12. After this, the exposure unit 1
In No. 4, while rotating the rotating drum 12 at a high speed at a predetermined rotation speed, in synchronization with the rotation of the rotating drum 12, the recording head unit 38 irradiates the printing plate 16 with a light beam modulated based on image data. It has become. As a result, the printing plate 16 is scanned and exposed based on the image data.

Further, in the exposure section 14, when the scanning exposure of the printing plate 16 is completed, the trailing edge chuck 36 holding the trailing edge of the printing plate 16 faces the trailing edge chuck attachment / detachment unit 32 at the position of the rotary drum. 12, the trailing edge chuck attaching / detaching unit 32 removes the trailing edge chuck 36 from the rotary drum 12 to open the trailing edge of the printing plate 16.

Furthermore, in the exposure section 14, the printing plate 16
The rotary drum 12 is set to the printing plate 16 with its rear end opened.
The printing plate 16 is discharged from the rear end side along the tangential direction of the rotating drum 12 to the plate discharge guide 22 of the conveyance guide unit 18 by being rotated in the take-out direction, and then is conveyed to the developing device in the next step. is there.

Next, the structures of the rotary drum 12 and the tip chuck unit 10 will be described. FIG. 1 is a perspective view of the rotary drum 12 to which the tip chuck unit 10 is attached. As shown in this figure, the rotary drum 12 includes a plurality of (eight in this embodiment) drums 4.
0, a rotary shaft 42, and a receiving member 44.

Each drum 40 has a drum body 40A around which the printing plate 16 is wound, and a hub 40B provided at the center.
And a plurality of (four in the present embodiment) spokes 40D connecting the drum body 40A and the hub 40B with each other, and a hub hole 40C axially penetrating the hub 40B. The spokes 40D are provided radially along the radial direction of the drum 40.

These drums 40 are axially separated from each other, and are fixed coaxially and integrally rotatably to the rotary shafts 42 inserted through the hub holes 40C. The rotating shaft 42 is adapted to transmit a rotational force in the mounting exposure direction or the removing direction by the driving means. As described above, the rotating drum 12 is arranged so that the drums 40 are spaced apart from each other in the axial direction, so that the weight is reduced, that is, the rotational moment (the driving force of the driving means) is reduced.

The exposure unit 14 processes a plurality of types of printing plates 16 having different sizes.
In the interval of 0, various printing plates 16 are used for the rotary drum 12 respectively.
It is determined that the end portions of the various printing plates 16 in the width direction (direction orthogonal to the winding direction) are not positioned between the drums 40 when wound around the drum 40. On the other hand, the widthwise end of the printing plate 16 may be located between the drums 40.

Further, at the connecting portion between each drum 40A and one spoke 40D, holding recesses 40E which are open at both ends in the radial direction outside and in the axial direction are provided along the axial direction. The holding recesses 40E are arranged in a straight line in the connected state of the drums 40, and are substantially long rectangular parallelepiped-shaped receiving members 44 bridged over the drum bodies 40A (drums 40).
Is inserted and fixed without steps.

In this state, both ends of the receiving member 44 substantially coincide with the axially outer end faces of the drums 40 located at both ends of the rotary drum 12, respectively. The spoke 40D corresponding to the holding recess 40E to which the receiving member 44 is fixed is
The deformation of the drum body 40A is prevented against the centrifugal force of the tip chuck unit 10 attached to the receiving member.

The tip chuck unit 10 is attached to the receiving member 44 constituting the rotary drum 12 described above. The tip chuck unit 10 includes a plurality of (13 in the present embodiment) base blocks 46 fixed to the receiving member 44 by press fitting, screwing, or the like. The base blocks 46 are arranged at substantially equal intervals along the longitudinal direction of the receiving member 44, and the base blocks 46 at both ends are
Each is located at the longitudinal end of the receiving member 44.

As shown in FIG. 2, each base block 46 has a shaft hole 46A penetrating in the longitudinal direction of the receiving member 44 and arranged coaxially therewith. A support shaft 48 is inserted through these shaft holes 46A. That is, the base block 46 is configured to support the support shafts 48 parallel to the rotation shaft 42 of the rotary drum 12 at substantially equal intervals and prevent (suppress) the support shafts 48 from bending.

A plurality of tip chucks 26 are rotatably supported on the support shaft 48. As shown in FIG. 3, the tip chuck 26 includes a chuck body 50 as a rotating member provided with a shaft hole 50A into which the support shaft 48 is inserted. A clamp part 52 is provided at one end of the chuck body 50 so as to project downward in the plane of the drawing of FIG. 3, and clamps the printing plate 16 with the receiving member 44.

As a result, in each tip chuck 26 rotatably supported by the support shaft 48, the respective clamp parts 52 are received independently from each other by the chuck body 50 rotating about the support shaft 48. Member 44 (rotary drum 12
The outer peripheral surface) can be contacted and separated.

The vicinity of the end of the chuck body 50 opposite to the clamp part 52 with the shaft hole 50A interposed therebetween is a pressing part 50B which is pressed by the telescopic rod 28A of the chuck opening / closing unit 28. This chuck body 5
A spring receiving portion 50C is provided between the zero pressing portion 50B and the shaft hole 50A. The other end of the spring 54 whose one end is locked to the receiving member 44 is locked to the spring receiver 50C. The chuck body 50 is urged by the urging force of the spring 54 in a direction in which the clamp portion 52 contacts the receiving member 44.

As described above, in the tip chuck 26, the clamping portion 52 is normally received by the receiving member 44 by the urging force of the spring 54.
When the pressing portion 50B is pressed by the telescopic rod 28A, the pressing portion 50B swings against the urging force of the spring 54, and the clamp portion 52 causes the clamp portion 52 to move as shown by an imaginary line in FIG.
And the receiving state (moving to the releasing position), the printing plate 1 is placed between the clamp portion 52 and the receiving member 44.
When the chuck opening / closing unit 28 pulls back the telescopic rod 28A with the end portion of the winding direction 6 being inserted, the spring 5
The end portion of the printing plate 16 is clamped (moved to the clamping position) between the clamp portion 52 and the receiving member 44 by the urging force of 4. That is, the clamp portion 52 of the tip chuck 26 can be moved between the holding position and the releasing position by rotating the chuck body 50 around the support shaft 48.

Further, the chuck body 50 has a pressing portion 5
A screw hole 56 is provided as a screw portion for opening on the end surface on the 0B side. A male screw portion 60 provided integrally with the weight member 58 is screwed into the screw hole 56. Further, the male screw portion 60 has a holding nut 62 for fixing (non-rotating).
Are screwed together.

As a result, the center of gravity of the tip chuck 26 is located closer to the pressing portion 50B than the shaft hole 50A (see FIG. 3). Then, when the rotary drum 12 rotates at a high speed, a centrifugal force is generated in a direction in which the pressing portion 50B side of the tip chuck 26 is separated from the receiving member 44, and this centrifugal force is generated by the chuck body 50 that is rotatable around the support shaft 48. Clamp part 5
2, the pressing force of the printing plate 16, that is, the clamp portion 5
2 is converted into a clamping force for clamping the printing plate 16 with the receiving member 44.

Further, by adjusting the screwing amount (screw-in depth) of the male screw portion 60 into the screw hole 56, the weight member 58 is brought into contact with and separated from the chuck body 50, and the center of gravity of the tip chuck 26 (the above centrifugal force). The magnitude of the force) can be changed, and the clamping force can be adjusted. The adjusted state is maintained by tightly tightening the presser nut 62 in the adjusted state.

The part of the chuck body 50 (part of the pressing portion 50B side including the screw hole 56), the weight member 58, and the male screw portion 60 described above correspond to the "clamping force imparting portion" in the present invention. Of these, the screw hole 56 and the male screw portion 60
And correspond to the “clamping force adjusting means” in the present invention.

The present embodiment (maximum of about 1200 m
In the case of being applied to the rotary drum 12 on which the m-width printing plate 16 can be wound), the tip chuck unit 10 is provided with four tip chucks 26 having the above-mentioned configuration, four each between the base blocks 46, for a total of 48. . Further, the tip chucks 26 are arranged apart from each other in the longitudinal direction of the receiving member 44, and the separation distance is made constant by the base block 46 or the spacer 64.

Specifically, as shown in FIG. 4, the opposing interval L of each base block 46 is approximately 100 mm, and the width W1 of each clamp portion 52 (tip chuck 26) is approximately 10 mm.
The distance D1 between the adjacent clamp portions 52 is approximately 20 mm. That is, the width of each base block 46 and the width of each spacer 64 are approximately 20 mm.

The width W1 and the distance D1 are reference values of 30 mm experimentally obtained in the exposure unit 14 as the non-holding distance for maintaining the close contact state of the printing plate 16 with the rotary drum 12 between the holding points (the above-mentioned value). It is not the maximum of the non-holding distance) or less.

Further, in this state, the clamping force for each clamp portion 52 of each tip chuck 26 (the clamping force obtained by adding the clamping force obtained by converting the centrifugal force when the rotary drum 12 rotates to the clamping force by the spring 54). The amount of screwing of each male screw portion 60 into the screw hole 56 is adjusted so that is substantially constant. As a result, the variation of the clamping force in each clamp portion 52 is suppressed within the allowable range.

In the chuck opening / closing unit 28, the corresponding expansion / contraction rods 28A of the tip chucks 26 are integrally expanded / contracted (for example, the ends on the opposite side to the pressing side are connected to each other). The pressing portion 50B of each tip chuck 26 is simultaneously pressed or released.

Next, the operation of this embodiment will be described.

The transport guide unit 18 of the printing plate automatic exposure device inserts the printing plate 16 fed into the puncher 24. The puncher 24 forms a notch at the tip of the printing plate 16. The printing plate 16 in which the notch is formed is returned to the plate feed guide 20 of the transport guide unit 18.

The printing plate 16 on the plate feed guide 20 is conveyed along the tangential direction to the rotary drum 12 stopped at the printing plate mounting position. At this time, the chuck opening / closing unit 28 is operated, and the telescopic rod 28A extends to press the pressing portion 50B of the tip chuck 26.

Then, the tip chuck 26 is rotated to separate the clamp portion 52 from the receiving member 44 to be in the receiving state. Then, by the above-mentioned conveyance, the printing plate 16 is inserted between the clamp portion 52 in the receiving state and the receiving member 44, and the printing plate 16 is abutted against the positioning pin to be positioned. When the telescopic rod 28A of the chuck opening / closing unit 28 is pulled back in this state, the tip of the printing plate 16 is clamped between the receiving member 44 and the clamp portion 52 by the urging force of the spring 54.

When the rotary drum 12 rotates in the mounting exposure direction and the squeeze roller 30 moves to the rotary drum 12 side while holding the front end of the printing plate 16, the printing plate 1
6 is tightly wound around the outer peripheral surface of the rotary drum 12. Then, when the trailing edge of the printing plate 16 reaches a position facing the trailing edge chuck attaching / detaching unit 32, the trailing edge chuck 36 of the trailing edge chuck attaching / detaching unit 32 is attached to the rotating drum 12 and rotates with the trailing edge chuck 36. The rear end of the printing plate 16 is held between the outer peripheral surface of the drum 12.

With the above, preparation for exposure is completed. In this state, the image data is read and the recording head unit 3
The exposure process is started by the light beam from 8. In the exposure process, the rotary drum 12 is rotated at high speed (main scanning).
Meanwhile, the so-called scanning exposure is performed in which the recording head unit 38 is moved in the axial direction of the rotary drum 12.

At this time, with the rotation of the rotary drum 12, a centrifugal force is generated in the direction in which the pressing portion 50B side (the portion corresponding to the holding force applying portion) of each tip chuck 26 is separated from the receiving member 44, and The pressing force with which the clamp part 52 presses the printing plate 16 by the chuck body 50, which is rotatably supported by the support shaft 48 by the centrifugal force, that is, the clamp part 52.
And the receiving member 44 are converted into the clamping force of the printing plate 16 and added to the clamping force of the spring 54. This allows
The printing plate 16 is firmly held on the rotating drum 12 by the tip chuck unit 10, and the exposure process is performed in this state.

When the exposure process is completed, the transport guide unit 18 is switched (the plate discharge guide 22 is made to correspond to the rotary drum 12), and then the printing plate 16 wound around the rotary drum 12 is discharged in the tangential direction. At this time, the printing plate 16 is sent to the plate discharge guide 22.

When the printing plate 16 is sent to the plate ejection guide 22, the conveyance guide unit 18 is switched to move the plate ejection guide 2
2 is made to correspond to the discharge port, and the printing plate 16 is discharged. A developing unit is provided in the discharging direction, and the printing plate 16 is continuously developed.

Here, as shown in FIG. 5, the clamping force of each clamp portion 52 is adjusted by adjusting the screwing amount of the male screw portion 60 into the screw hole 56 (the position of the center of gravity of the tip chuck 26). Is substantially constant and the variation is suppressed within an allowable range. Therefore, the printing plate 16 is clamped by the clamping force of the clamp portion 52 (pressing force P shown in FIG. 5) which is substantially evenly distributed at predetermined intervals over the entire width. Hold properly.

Further, the distance D1 between the clamps 52 (distribution distance of the holding force) is set to about 20 mm, which is a reference value of 30 mm or less, as described above, and therefore each clamp 5 is
The floating of the non-sandwiched portion of the printing plate 16 between the two is prevented (the close contact state is maintained).

The width of each clamp portion 52 is W1.
Is as narrow as 10 mm, so dimensional accuracy and rigidity in the width direction are high. Therefore, the distribution of the clamping force in the width direction of each clamp portion 52 is less likely to vary, and the printing plate 16 does not become completely non-clamped at the center portion of each clamp portion 52 in the width direction (at least FIG. 5). The pressing force indicated by the broken line in FIG.

Further, since the width W1 of the clamp portion 52 is about 10 mm, which is not more than the reference value of 30 mm, even if only both ends in the width direction of each clamp portion 52 serve as pressing portions, the non-holding distance of the printing plate 16 is eliminated. Is 30 mm or less, and the printing plate 16 is prevented from floating at the center portion in the width direction (contact state is maintained).

FIG. 5 is a diagram showing the distribution of the pressing force (holding force) corresponding to a part (four pieces) of the plurality of clamp parts 52, and the alternate long and short dash line is the conventional one shown for comparison. Is a pressing force distribution by the clamp part of.

As described above, in the tip chuck unit 10 according to this embodiment, the printing plate 1 by the clamp portion 52 is used.
It is possible to reduce the variation in the pressing force of 6 (distribution of the holding force with the receiving member 44) and prevent the printing plate 16 from floating from the rotary drum 12.

In the tip chuck unit 10, the distance D1 between the clamp portions 52, which is less than or equal to the reference value, is larger than the width W1 of the clamp portions 52. As described above, it is possible to maintain the function of preventing the variation of the pressing force in the width direction of each clamp portion 52 without increasing the above. In other words, in the tip chuck unit 10,
While suppressing an increase in the number of clamp parts 52 (that is, the tip chucks 26), the printing plate 16 can be clamped and held on the rotating drum 12 with a proper distribution of pressing force without floating.

Furthermore, since the increase in the number of parts is prevented as described above, the rotation moment when the rotary drum 12 rotates can be reduced. In particular, since each tip chuck 26 is thinned as a whole (the conventional tip chuck is divided into four tip chucks 26 separated from each other), the tip chuck unit 10 as a whole is lightweight. Therefore, the rotation moment when the rotary drum 12 rotates is further reduced.

Further, here, the tip chuck unit 10
Then, since the clamping force in each clamp portion 52 can be adjusted by simply adjusting the screwing amount of the male screw portion 60 into the screw hole 56, the adjustment work is easy. In particular, adjustment of the clamping force (changing the position of the center of gravity of the tip chuck 26) is necessary for adjusting the screw portion 6
Since the screwing between 0 and the screw hole 56 is used, for example, fine adjustment of the clamping force is easier than the configuration in which the weight member 58 slides linearly with respect to the chuck body 50 to change the position of the center of gravity. is there. As a result, it is possible to further reduce the variation in the clamping force (pressing force) acting on the printing plate 16.

Further, for example, in the configuration in which the clamping force is adjusted by scraping off the weight member 58, it is difficult to readjust the clamping force while maintaining a predetermined clamping force. However, the clamping force adjusting means of the above configuration is used. In the provided tip chuck unit 10,
The clamping force can be readjusted while maintaining the predetermined clamping force. Furthermore, for example, the clamping force can be increased or decreased and set according to the rotation speed of the rotary drum 12.

The holding force adjusting means is realized by a very simple structure by the screw hole 56 provided in the chuck body and the male screw portion 60 provided in the weight member 58.

In the above embodiment, the width W1 of the clamp portion 52 is made equal to the width of the chuck body 50, and the flat end surface of the clamp portion 52 presses the printing plate 16, but the present invention is not limited to this. Is not limited to this, and may have a configuration according to a modified example as shown in FIG. 7 or FIG. Hereinafter, these modified examples will be described. Basically, the same components and parts as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted.

FIG. 7 shows a front end chuck unit 70 according to a first modification in a front view corresponding to FIG. As shown in this figure, the tip chuck unit 70
Each of the tip chucks 26 constituting the above has a clamp portion 72 instead of the clamp portion 52. Each of the clamp portions 72 has an arcuate tip end, and is tapered toward a portion that holds the printing plate 16.

The width W2 of the portion of the clamp portion 72 that substantially presses the printing plate 16 is about 2 mm to 3 mm, which is sufficiently smaller than the reference value of 30 mm. The width W1 of the chuck body 50 is about 10 mm, and the width D1 of each spacer 64 and the base block 46 is about 20 mm.
Since it is mm, the distance between the ends of the width W2 is about 2
It is set to 7 mm to 28 mm, which is also below the reference value.

Therefore, the tip chuck unit 70 according to the first modification can also achieve the same effect as the tip chuck unit 10 having the above-described configuration. Further, since each clamp portion 72 is formed in a tapered shape, the clamp portion 72 is rotatably supported by the support shaft 48, and the screw hole 56 and the male screw portion 6 are provided.
Chuck body 5 to which a weight member 58 is attached via
While maintaining the strength of 0 (the tip chuck 26), the width of the clamp portion 72 is further reduced, and the variation of the pressing force in the width direction of the clamp portion 72 is further reduced. Further, since the arc-shaped clamp portion 72 is continuously reduced in width from the chuck body 50 side, its rigidity is ensured and unnecessary deformation (deformation in the direction orthogonal to the width direction) is prevented.

Further, FIG. 8 shows a front end chuck unit 80 according to a second modification in a front view corresponding to FIG. As shown in this figure, each tip chuck 26 that constitutes the tip chuck unit 80 has a clamp portion 82 instead of the clamp portion 52. Each clamp portion 82 is formed in a tapered shape (triangular shape) toward a portion that holds the printing plate 16, and the widthwise central portion at the tip is substantially sharpened.

In this clamp portion 82, the width W3 of the portion that presses the printing plate 16 is a value sufficiently smaller than the reference value 30 mm (a value close to 0 mm), and the printing plate 16 is clamped in a substantially line contact state. It is supposed to do. Further, since the width W1 of the chuck body 50 is approximately 10 mm and the width D1 of each spacer 64 and the base block 46 is approximately 20 mm, the distance between the end portions of the width W3 is approximately 30 mm, which is the reference value above. The setting is almost the same (included below the reference value).

Therefore, the tip chuck unit 80 according to the second modification can achieve the same effect as that of the tip chuck unit 10 having the above configuration. In addition, since each clamp portion 82 is tapered, the same effect as that of the tip chuck unit 70 according to the first modification can be obtained. Further, it goes without saying that even if the clamp portion 82 is formed in a tapered trapezoidal shape, the same effect as that of the tip chuck units 10 and 70 can be obtained.

In the above-described embodiment and each modification, the above-mentioned reference value (rotation of the printing plate 16 between the nipping points) is used as a reference for the widths of the clamp parts 52, 72, 82 and the intervals between the clamp parts 52, etc. The non-holding distance at which the close contact state with the drum 12 is maintained) is 30 mm, but the present invention is not limited to this, and the reference value is, for example, the diameter or rotation speed of the rotating drum, the characteristics of the printing plate 16 ( It may be determined experimentally or theoretically in accordance with the strength of the waist based on the material, the thickness, etc.), the clamping allowance (length of the sandwiching portion in the circumferential direction of the rotary drum 12) by the clamp portion 52, and the like. When the clamp allowance is set small in order to increase the exposure range (image forming area) on the printing plate 16, it is necessary to set the reference value small (for example, between 20 mm and 25 mm).

Further, in the above-mentioned embodiment and each modified example, the example in which the sheet material holding device of the present invention is applied to the tip chuck units 10, 70, 80 is shown, but the present invention is not limited to this. For example, the sheet material holding device of the present invention can be applied to the trailing edge chuck 36 (rear edge chuck unit) that is attached to and detached from the rotary drum 12 by the trailing edge chuck attaching / detaching unit 32. The configuration of the trailing end chuck 36 except the attachment / detachment mechanism to / from the rotary drum 12 is basically the same as that of the leading end chuck 26.

Further, in the above-described embodiment and each modified example, the width W1, W2, W of each clamp portion 52, 72, 82 is obtained.
3 are the intervals D1, D2, D of the respective clamp parts 52, etc.
Although the preferable configuration is smaller than 3, the present invention is not limited to this, and for example, the width W1 or the like of each clamp portion 52 or the like may be equal to or more than the interval D1 or the like of each clamp portion 52 or the like. Needless to say, the number of the tip chucks 26 is not limited to that in the above embodiment.

Furthermore, in the above-described embodiment and each of the modified examples, the screw hole 56 constituting the clamping force adjusting means is provided in the chuck body 50, and the male screw portion 60 is provided with the weight member 58.
However, the present invention is not limited to this, and the screw hole 56 is provided in the weight member 58 and the male screw portion 6 is provided.
0 may be provided on the chuck body 50. Further, the clamping force adjusting means is not limited to the configuration in which the screw hole 56 and the male screw portion 60 are screwed together, and for example, the chuck body 5
0 and the weight member 58, the structure in which the mounting angle of the arm member with respect to the longitudinal direction of the chuck main body 50 is changed, and the chuck member 50 is housed in the chuck main body 50.
The position of the weight member 58 urged to one side in the longitudinal direction may be engaged with the tip of the screw screwed to the chuck body 50 to change the screwing amount of the screw.

Further, in the above-described embodiment, an example applied to the attachment of the tip chuck unit 10 to the rotary drum 12 which is constituted by the plurality of drums 40 and the receiving members 44 bridged over the respective drums 40. However, it is needless to say that the present invention is not limited to this and may be applied to, for example, attachment of the tip chuck unit 10 to the rotary drum 12 configured by one drum.

[0101]

As described above, the sheet material holding device according to the present invention has an excellent effect of reducing the variation in the pressing force of the sheet material by the clamp portion and preventing the sheet material from floating from the rotary drum. Have.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state in which a tip chuck unit according to an embodiment of the present invention is attached to a rotary drum.

FIG. 2 is an enlarged perspective view of a part of the tip chuck unit according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a tip chuck that constitutes a tip chuck unit according to an embodiment of the present invention.

FIG. 4 is a front view showing the width dimension and spacing of the tip chucks constituting the tip chuck unit according to the embodiment of the present invention.

FIG. 5 is a diagram showing a pressing force distribution of the printing plate when the printing plate is clamped by the tip chuck unit according to the embodiment of the present invention.

FIG. 6 is a schematic view showing an exposure unit of the printing plate automatic exposure apparatus to which the tip chuck unit according to the embodiment of the present invention is applied.

FIG. 7 is a front view corresponding to FIG. 4, showing a tip chuck unit according to a first modification of the embodiment of the present invention.

FIG. 8 is a front view corresponding to FIG. 4, showing a tip chuck unit according to a second modification of the embodiment of the present invention.

FIG. 9 is a perspective view showing a conventional sheet material holding device.

[Explanation of symbols]

10 tip chuck unit (sheet material holding device) 12 rotary drum 16 printing plate (sheet material) 26 tip chuck (rotating member) 44 receiving member (rotating drum) 50 chuck body (rotating member, clamping force applying means) 52 clamp Part 56 Screw hole (female screw part, holding force adjusting means) 58 Weight member (holding force applying means) 60 Male screw part (holding force adjusting means) 70, 80 Tip chuck unit (sheet material holding device) 72, 82 Clamping part

Claims (5)

[Claims] 1. A sheet material holding device for sandwiching an end portion in the winding direction of the sheet material with an outer peripheral surface of a rotating drum around which the sheet material is wound, each axis line being parallel to a rotation axis of the rotating drum. A plurality of rotating members that are rotatably supported around and a plurality of rotating members that are respectively provided on one side with respect to the center of rotation of the plurality of rotating members and that rotate between the outer peripheral surface. A clamp portion that can take a sandwiching position for sandwiching the sheet material and a release position for releasing the sandwiching, and a clamp portion that is respectively provided on the other side with respect to the center of rotation of the plurality of rotating members, and rotates with the rotation drum. The rotating member converts the generated centrifugal force into the clamping force of the sheet material in the clamp part, and further comprises a clamping force applying part capable of adjusting the clamping force. Both the size and the interval between the adjacent clamp portions are set to be equal to or less than the maximum value of the non-sandwiching distance capable of maintaining the close contact state of the sheet material to the rotating drum between the sandwiching points. Material holding device. 2. The sheet material holding device according to claim 1, wherein a width dimension of the clamp portions is set to be smaller than an interval between the clamp portions. 3. The sheet material holding device according to claim 2, wherein the clamp portion is formed so as to be tapered toward a portion for sandwiching the sheet material. 4. The holding force applying portion is provided between the weight member connected to the other side of the rotating member and the weight member and the rotating member, and changes a fixing position of the weight member. The sheet material holding device according to any one of claims 1 to 3, wherein the sheet material holding device is configured to include a possible clamping force adjusting means. 5. The clamping force adjusting means has a male screw portion provided on one of the weight member and the rotating member, and a female screw portion provided on the other and screwed into the male screw portion. The sheet material holding device according to claim 4, wherein the sheet material holding device is configured as follows.