Patent Application
20140318340
The present invention relates to a rotary die cutter comprises a pair of a magnet roller on which a flexible die is mounted, and an anvil roller arranged opposite to the magnet roller and punches out a sheet is supplied one by one between the magnet roller and the anvil roller.
A conventional rotary die cutter comprises a magnet roller, an anvil roller arranged opposite to the magnet roller, a single flexible die mounted on the magnet roller and a sheet feed unit supplying a sheet one by one between the magnet and anvil rollers, in which the sheet supplied from the sheet feed unit is punched out by the flexible die (the term “punch” may be used to denote not only its original meanings but also “emboss”, “score”, “perforate” and so on. The same applies hereinafter.) while the sheet is conveyed by the magnet and anvil rollers (See, for example, JP 2003-237018 A and JP 2012-161859 A).
In such rotary die cutter, the punching of one sheet is completed each time the magnet and anvil rollers make one revolution because the punching is done with the conveyance of the sheet by the magnet and anvil rollers. Therefore, commonly, in order to maximize a production volume per revolution of the magnet and anvil rollers, that is, a. production volume per hour, the largest possible size of the flexible die (the flexible die extending over the whole circumference of the magnet roller) is used. This configuration is quite effective in mass production of the same type of product.
On the other hand, this conventional rotary die cutter has the disadvantages that a sheet needs to have a certain size adapted for the flexible die and the use of a small size of the flexible die causes reduction of a production volume per revolution of the magnet and anvil rollers. Consequently, even when a small amount of small-sized products which are considerably smaller than a processable size of sheet, it is necessary to form a number of the same punching patterns on a large-sized flexible die and punch a certain size of sheet by use of the large-sized flexible die, which raises production costs.
It is, therefore, an object of the present invention to provide a rotary die cutter enable manufacturing of a wide variety of products in small quantities at low cost.
In order to achieve this object, according to the present invention, there is provided a rotary die cutter comprising: a magnet roller; an anvil roller arranged in parallel with and opposite to the magnet roller with a gap therebetween; a single sheet-like flexible die mounted on the magnet roller; a pair of feed rollers spaced from the pair of magnet and anvil rollers; a first drive mechanism rotating the magnet and anvil rollers in such a way that the magnet and anvil rollers are constantly rotated synchronously with each other at an equal circumferential velocity, a second drive mechanism rotating the pair of feed rollers; a controller controlling the first and second drive mechanisms, the magnet and anvil rollers being rotated in a direction to receive a sheet from the pair of feed rollers; and a sensor arranged between the pair of magnet and anvil rollers and the pair of feed rollers to detect the passage of a leading end of the sheet, wherein every time a detection signal is outputted from the sensor, the pair of feed rollers is intermittently rotated in a direction to convey the sheet to the pair of magnet and anvil rollers, or alternately rotated in the direction to convey the sheet to the pair of the magnet and anvil rollers and the reverse direction at a predetermined timing corresponding to a peripheral velocity and a rotational position of the flexible die so that a plurality of areas spaced from each other in the conveying direction on the sheet are punched by the flexible die while the sheet is conveyed between the magnet and anvil rollers by the pair of feed rollers. Here, the term “punch” may be used to denote not only its original meanings but also “emboss”, “score”, “perforate” and so on. The same applies hereinafter.
According to a preferred embodiment of the present invention, the controller comprises an input unit for receiving input of the data about the punching of the sheet including a size of the sheet, a distance from the leading end of the sheet to a leading end of a punching range on the sheet, and a position of a start point of punching on the sheet at each punching operation of the flexible die, and the timing of rotation of the pair of feed rollers is determined by the controller based on the data about the punching of the sheet, the rotational velocity of the pair of feed rollers, and the peripheral velocity and the rotational position of the flexible die.
According to another preferred embodiment of the present invention, the rotary die cutter further comprises: a sheet supply unit supplying sheets one by one from a sheet stack; and a suction conveyor belt extending between the sheet supply unit and the pair of feed rollers so as to convey the sheet from the sheet supply unit to the pair of feed rollers while the sheet is sucked by the suction conveyor belt at the underside thereof, wherein the sheet supply unit and the suction conveyor belt is controlled by the controller so that the suction conveyor belt constantly operates while the sheet supply unit supplies the next sheet every time the punching of the previous sheet is completed.
According to the present invention, the first drive mechanism rotating the magnet and anvil rollers and the second drive mechanism rotating the pair of feed rollers are arranged independently of each other so that the pair of magnet and anvil rollers does not contribute to conveying the sheet substantially but exclusively performs the punching operation of the sheet on the one hand and the pair of feed rollers conveys the sheet on the other hand, and thereby the punching of the sheet is performed while the sheet is conveyed by the pair of feed rollers between the magnet and anvil rollers. Consequently, the punching can be accurately done at the predetermined positions on the sheet independently of a size of the flexible die.
Furthermore, the pair of feed rollers is intermittently rotated in the direction to convey the sheet to the pair of magnet and anvil rollers, or alternately rotated in the direction to convey the sheet to the pair of magnet and anvil rollers and the reverse direction at the predetermined timing so that the sheet is intermittently moved forward, or repeatedly moved forward and backward with respect to the pair of magnet and anvil rollers, and thereby the pair of magnet and anvil rollers can make two or more revolutions while the sheet passes through the pair of magnet and anvil rollers. Consequently, a length of the flexible die along a circumference of the magnet roller can be limited to the bare minimum, so that the cost of manufacturing the flexible die is considerably reduced when compared to the above-mentioned conventional rotary die cutter. Therefore, it is possible to achieve the manufacturing of a wide variety of products in small quantities at low cost.
A preferred embodiment of the present invention will be described below with reference to accompanying drawings.
The suction conveyor belt 2 comprises a pair of horizontal roller 6, 7 arranged adjacent to the sheet supply unit 1 and the punching unit 3 and extending across and perpendicular to a sheet conveying path, and an endless belt 10 extending between the pair of rollers 6, 7. Vents are uniformly formed on the endless belt 10. One roller 6 of the pair of rollers 6, 7 is provided with a first pulley 8 at a shaft thereof and a motor 11 is arranged below the roller 6. A drive shaft of the motor 11 extends parallel to the roller 6 and is provided with a second pulley 12. An another endless belt 13 extends between the first and second pulleys 8, 12. Thus the endless belt 10 is circulated by the motor 11.
Furthermore, a suction duct 14 is arranged below an upper straight portion of the endless belt 10 between the pair of rollers 6, 7. The suction duct 14 is provided with intake vents at its upper surface and connected to a vacuum pump 15. Thus the endless belt 10 circulates and the vacuum pump operates so that the sheet S supplied from the sheet supply unit 1 is conveyed to the punching unit 3 while the sheet S is sucked by the suction conveyor belt 10 at the underside thereof. The motor 11 and the vacuum pump 15 are controlled by the controller 5
The punching unit 3 comprises a magnet roller 16 arranged parallel to the pair of rollers 6, 7, and an anvil roller 17 arranged in parallel with and opposite to the magnet roller 16 with a gap therebetween. As shown in
Referring to
The motor 19, the third and fourth pulleys 18, 19a, the first timing belt 20 and the connecting mechanism (not shown) construct a first drive mechanism rotating the magnet and anvil rollers 16, 17.
A rotary encoder 22 is arranged between the anvil roller 17 and the motor 19. A rotary shaft of the rotary encoder 22 is provided with a fifth pulley 21 and extends parallel with the shaft of the anvil roller 17. The fifth pulley 21 contacts with the first timing belt 20 so as to be rotated by the circulation of the first timing belt 20. The control unit 5 detects a rotational position of the anvil roller 17, that is, the magnet roller 16 (that is, the flexible die 29) based on pulses outputted from the rotary encoder 22.
The punching unit 3 further comprises a pair of feed rollers 23a, 23b spaced upstream of the pair of magnet and anvil rollers 16, 17 and arranged adjacent to the downstream of the suction conveyor belt 2. The pair of feed rollers 23a, 23b consists of a pair of rollers which are arranged opposite to each other in a vertical direction and extend parallel to the magnet and anvil rollers 16, 17.
A lower roller 23b of the pair of feed rollers 23a, 23b is provided with a sixth pulley 24 at a shaft thereof. A servo motor 25 is arranged below the lower roller 23b, and a drive shaft of the servo motor 25 is provided with a seventh pulley 26 and extends parallel to the lower roller 23b. A second timing belt 27 extends between the sixth and seventh pulleys 24, 26 so that the pair of feed rollers 23a, 23b are rotated in clockwise and anticlockwise directions by the servo motor 25. The servo motor 25 is controlled by the control unit 5. The servo motor 25, the sixth and seventh pulleys 24, 26 and the second timing belt 27 construct a second drive mechanism rotating the pair of feed rollers 23a, 23b.
A sensor 28 is arranged downstream of the pair of feed rollers 23a, 23b so as to detect the passage of a leading end of the sheet S. Detection signals are sent to the controller 5. A flat support plate 32 is arranged between the pair of feed rollers 23a, 23b and the pair of magnet and anvil rollers 16, 17 so as to support the underside of the sheet conveyed by the pair of feed rollers 23a, 23b. The support plate 32 is provided if needed.
The controller 5 comprises an input unit for receiving input of the data about the punching of the sheet, for example, a size of the sheet S, a distance from the leading end of the sheet S to a leading end of a punching range on the sheet S, and a position of a start point of punching on the sheet S at each punching operation of the flexible die 28. In this embodiment, the input unit is composed of a touch panel display 9 and a numerical key pad (not shown).
In this case, if the distance from the reading end of the sheet to the leading end of the whole punching range on the sheet and the distances between the leading ends of the adjacent punching ranges on the sheet can be inputted separately, for example, when a sheet is punched according to a pattern printed thereon, even though a shrink of the sheet due to printing causes misalignment of shapes of the printed pattern, correspondingly, it is possible to easily correct the position of punching.
Thus the sheet S supplied by the sheet supply unit 1 is conveyed by the suction conveyor belt 2 and fed in a gap between the pair of feed rollers 23a, 23b. In this case, the suction conveyor belt 2 constantly operates while the sheet supply unit 1 supplies the next sheet S every time the punching of the previous sheet S is completed. The operation of the suction conveyor belt 2 does not block the conveyance of the sheet S by the rotation of the pair of feed rollers 23a, 23b in the clockwise and anticlockwise directions.
The sheet S fed in the gap between the pair of feed rollers 23a, 23b is conveyed to a gap between the magnet and anvil rollers 16, 17 by the pair of feed rollers 23a, 23b while being guided by the support plate 32. Then, every time a detection signal is outputted from the sensor 28, the pair of feed rollers 23a, 23b is intermittently rotated in a direction to convey the sheet S to the pair of magnet and anvil rollers 16, 17, or alternately rotated in the direction to convey the sheet S to the pair of the magnet and anvil rollers 16, 17 and the reverse direction at a predetermined timing corresponding to a peripheral velocity and a rotational position of the flexible die 29 (the rotation of the pair of feed rollers 23a, 23b in the direction to convey the sheet to the pair of magnet and anvil rollers 16, 16 will be referred as “forward rotation” and the rotation of the pair of feed rollers 23a, 23b in the reverse direction will be referred as “reverse rotation” hereinafter). The timing of rotation of the pair of feed rollers 23a, 23b is determined by the controller 5 based on the data about the punching of the sheet S, the data being inputted through the input unit, the rotational velocity of the pair of feed rollers 23a, 23b, and the peripheral velocity and the rotational position of the flexible die 29.
Thus the sheet S is intermittently advanced toward, or alternately advanced toward and retreated from the pair of magnet and anvil rollers 16, 17 so that, as shown in
The ejecting unit 4 comprises a conveyor belt 30 extending from an exit of the pair of magnet and anvil rollers 16, 17 to an exit of the rotary die cutter, a feed roller 31 arranged adjacent to the downstream of the conveyor belt 30. The feed roller 31 extends perpendicularly to the conveyor belt 30 and contacts the upper surface of the conveyor belt 30. The sheet S punched by the punching unit 3 is conveyed by the conveyor belt 30 and the feed roller 31 and discharged from the exit of the rotary die cutter.
Next, an operation of the punching unit 3 of the rotary die cutter according to the present invention will be explained in detail. As shown in
Referring to
When the tail end of the flexible die 29 is separated from the sheet S, the pair of feed rollers 23a, 23b starts decelerating, and when the punched area G1 of the sheet is completely ejected from the pair of magnet and anvil rollers 16, 17, the pair of feed rollers 23a, 23b stops rotating (See, the point C in
Next, the sheet S is retreated by the reverse rotation of the pair of feed rollers 23a, 23b (See, the point D in
As before, the punching is performed by the flexible die 29 in the second punching range m2 on the sheet S during one revolution of the pair of magnet and anvil rollers 16, 17, and the punching is performed by the flexible die 29 in the third punching range m3 on the sheet S during further one revolution of the pair of magnet and anvil rollers 16, 17. Thus, as shown in
Secondly, an operation of the punching unit 3 when the rotary die cutter of the present invention operates in another operation mode will be explained. In this operation mode, the punching is performed while the sheet S is intermittently advanced toward the pair of magnet and anvil rollers 16, 17.
Referring to
When the punched area G1 of the sheet S is completely ejected from the pair of magnet and anvil rollers 16, 17, the pair of feed rollers 23a, 23b stops rotating and therefore, the sheet S remains stationary. On the other hand, the pair of magnet and anvil rollers 16, 17 continues to rotate while the pair of feed rollers 23a, 23b stops rotating (See, the point C in
Then the pair of feed rollers 23a, 23b starts the forward rotation right before the leading end of the flexible die 29 reaches the lowest point of the periphery of the magnet roller 16 again, so that the sheet S is advanced (conveyed toward the downstream between the magnet and anvil rollers 16, 17) at the same speed as the peripheral velocity of the pair of magnet and anvil rollers 16, 17. In this period, a second punching operation by the flexible die 29 is performed within the second punching range m2 on the sheet S (See, the point D in
When the punched area G2 of the sheet S is completely ejected from the pair of magnet and anvil rollers 16, 17, the pair of feed rollers 23a, 23b stops rotating and therefore, the sheet S remains stationary. On the other hand, the pair of magnet and anvil rollers 16, 17 continues to rotate while the pair of feed rollers 23a, 23b stops rotating. Thus the punching is performed by the flexible die 29 in the second punching range m2 on the sheet S during one revolution of the pair of magnet and anvil rollers 16, 17. Further, as before, the punching is performed by the flexible die 29 in the third punching range m3 on the sheet S during one revolution of the pair of magnet and anvil rollers 16, 17. Thus, as shown in
In the rotary die cutter of the present invention, the first drive mechanism rotating the magnet and anvil rollers 16, 17 and the second drive mechanism rotating the pair of feed rollers 23a, 23b are arranged independently of each other so that the pair of magnet and anvil rollers 16, 17 does not contribute to conveying the sheet S substantially but exclusively performs the punching operation of the sheet S on the one hand and the pair of feed rollers 23a, 23b conveys the sheet S on the other hand, and thereby the punching of the sheet S is performed while the sheet S is conveyed by the pair of feed rollers 23a, 23b between the magnet and anvil rollers 16, 17. As a result, the punching can be accurately done at the predetermined positions on the sheet S independently of a size of the flexible die 29.
In addition, the pair of feed rollers 23a, 23b is intermittently rotated in the direction to convey the sheet S to the pair of magnet and anvil rollers 16, 17, or alternately rotated in the direction to convey the sheet S to the pair of magnet and anvil rollers 16, 17 and the reverse direction at the predetermined timing in such a way that the sheet S is intermittently moved forward, or repeatedly moved forward and backward with respect to the pair of magnet and anvil rollers 16, 17, and thereby the pair of magnet and anvil rollers 16, 17 can make two or more revolutions while the sheet S passes through the pair of magnet and anvil rollers 16, 17. Consequently, a length of the flexible die 29 along a circumference of the magnet roller 16 can be limited to the bare minimum, so that the cost of manufacturing the flexible die 29 is considerably reduced when compared to the above-mentioned conventional rotary die cutter. Therefore, it is possible to achieve the manufacturing of a wide variety of products in small quantities at low cost.
Although the present invention has been explained based on some preferred embodiment thereof, the present invention is not limited to those embodiments and one skilled in the art can easily devise various modified embodiments within the scope of the claims of the present application. For example, although a servo motor is used in the first drive mechanism rotating the pair of feed rollers 23a, 23b and a general motor is used in the second drive mechanism rotating the pair of magnet and anvil rollers 16, 17 and a rotary encoder is used for detection of rotational position of the magnet roller 16 in the above-mentioned embodiments, servo motors or stepping motors may be used in both of the first and second drive mechanisms.
Although the punching of the same pattern is performed on the sheet S at regular intervals in the conveying direction in the above-mentioned embodiments, the punching pattern of the same pattern may be performed a plurality of areas of the sheet randomly spaced in the conveying direction. Although the punching pattern is two-dimensional in the above-mentioned embodiments, as shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 2013-093711 | Apr 2013 | JP | national |
| 2014-059951 | Mar 2014 | JP | national |
