JPH04256598A - Cross cutter for web material with printed image - Google Patents

Abstract

PURPOSE: To discharge a separating belt at high efficiency and without a trouble without requiring a large amount of cost on a cross cutter for a web material with a printed image consisting of a cutter wheel, a pair of two cutters provided on it and an opposite cutter provided standstill. CONSTITUTION: A suction and blast hole 9 free to reciprocally work by negativepressure and blast air through a valve control device dependent on a rotating position of a cutter wheel is provided between cutters 4a, 4b. A separating belt 8 which is cut off is held by negative pressure between the cutters of the suction and blast hole 9, carried to a specific position, blown off by blast air and discharged. The valve control device to change blast air and suction air over to each other is provided on an end surface side of the cutter wheel 3, furnished with an inlet and an outlet to be rotationally displaced, and they are opened by a pipe connecting port connected to the suction and blast hole 9 through passages 16a, 16b, 17 in the inside of the cutter wheel 3.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention relates to a cutter wheel equipped with a pair of parallel cutters, a stationary opposed cutter, and a cutter wheel provided with a cutter wheel provided with a pair of parallel cutters, and a cutter wheel provided with a cutter wheel provided with a pair of parallel cutters, a stationary opposed cutter, and a cutter wheel provided with a cutter wheel provided with a pair of parallel cutters. The present invention relates to a cross cutter for web material with printed images, comprising a removal device operated by suction air.

0002

BACKGROUND OF THE INVENTION In the printing industry, there are increasingly high demands on the processing steps from paper rolls to printed sheets. The sheets must already be imaged and cut in the rotary printing press, and labor-intensive operations for depiling, shaking and face-cutting the sheets must be avoided. For this purpose, it is necessary to remove the separation bands of unprinted areas between printed images or areas printed with printing marks, which occur when cross-cutting, from the area of the transport path of the cut sheets. Otherwise, stray stripping bands will interfere with subsequent processing steps.

In the case of known cross cutters of the type mentioned at the outset, the bladed roller has a slit between each pair of parallel cutters, into which the cutting strip is sucked, and air pressure is applied through the hollow wheel journal. is discharged by. Such a cross cutter has no practical value because the discharge passage is easily clogged. Enlarging the cross-sectional area of the discharge channel in order to reduce the risk of clogging reduces the associated stability of the cutter wheel, especially if the cutter wheel
A converse reduction results when a pair of parallel cutters is provided.

In the case of other crosscutters, purely mechanical means are provided for retaining and removing the cutting strip. In this cross cutter, a cutter wheel with a pair of parallel cutters is provided with a hardened smooth counterwheel that rotates synchronously. This counterwheel is provided with protruding needles which are thrust into the web material so as to fix the separation strip and which are scraped off on the opposite side by the fixed projections of the comb.

Furthermore, other cutting devices for web materials and sheets are known, which devices consist of two synchronously rotating wheels, one of which is fitted with a cutter for cutting the Fenster. The other wheel is designed as a counterpressure wheel (DE 1928966 A1). In this cutting device, a suction and blowing hole is provided inside the cutter, which hole is connected to a passage extending over a part of the circumference of the cutter wheel. This cutter wheel is surrounded by a suction cover such that the passage hole is inside the suction cover during cutting. In this way, the cutting strip is sucked in during cutting. Upon further rotation, the separation strip is fixed by the suction force while the entrance of the passage is in the suction cover. However, if the entrance of the passage passes past the suction cover, air is drawn in from the outside air through the suction passage and the separation strip is released for evacuation. If the power is low, it may be possible to hold the separating strip and release it in the area of the suction cover to eject it. In the case of high powers, such as are currently required in the case of rotary offset printing presses, in order to maintain the separation strip, which is exposed to large centrifugal forces due to high rotational speeds, it is necessary to The negative pressure applied would be inappropriate. It is possible to hold and/or release the separating strip without direct active action due to large underpressures and overpressures.

[0006]Finally, other devices are known for cutting sheet or web material, in which the cutting strip produced during cutting is held by negative pressure and is replaced for cutting and discharged. At a suitable location, they are separated by supplying blowing air. In this device, the suction and blowing air is supplied and discharged by hollow shafts, tubes and valves. However, such devices are not welcomed as unsuitable devices due to the high costs involved (German Published Patent Application No. 1928966, page 2 bottom to page 3 top).

[0007]

OBJECTS OF THE INVENTION The basic object of the invention is to
It is an object of the present invention to provide a cross cutter for web material with printed images of the type mentioned at the outset, in which the resulting separation band can be discharged with high efficiency and without any hindrance.

[0008]

[Means for Solving the Problem] This purpose is to provide a cross cutter in which the removing device has a suction/blow hole between the cutters of each pair of cutters, and the suction/blow hole is used to draw in air during cutting. source and in the rotational range turned to the cutting rotation position, so as to be connected to the spraying source;
Via the at least one passageway extending through the cutter wheel, the suction and blowing holes can be connected by the valve control device depending on the angle of rotation of the rotating cutter wheel and are separated by the blowing air. A suction cover for the separation band is provided around the cutter wheel in said rotation range, in which case a valve control device is provided on the cutter wheel and a fixed control of the suction and blowing air source;
This is achieved by having oppositely rotationally displaced inlets and outlets and at least one pipe connection which alternately opens said inlets and outlets of the passages leading to and leaving the suction and blowing holes. In that case, an inlet is provided on one end side of the cutter wheel, an outlet is provided on the other end side, and each channel on both end sides has a pipe connection.

[0009]

[Operation] In the case of the cross cutter of the present invention, it is possible to increase the negative pressure and overpressure of the suction/blow air source in the suction/blow hole by means of the valve control device.
Separation bands occurring between the cutters of the cutter pair are reliably removed from the process even at high powers. The switching operations of the valve control device with rapid pressure rises and falls, which are necessary in the case of crosscutters used in printing shops, can be controlled without problems by a special design of the valve control device. For 30 printed images per second, 60 air changes per second are required. If the switching action of the valve control device is determined to be 1/3 of a turn in each case, there is a surplus of several milliseconds for the rise and fall of the pressure. The switching induced from the relative movement between the cutter wheel and the fixed inlet and outlet of the suction and blowing air source ensures that this requirement is met.

[0010] To assist in the evacuation of the resulting separation zone, a floating nozzle with a conveying action is provided, as shown in another embodiment of the invention, which delivers blowing air to the inside of the suction cover.

Particularly when high rotational speeds inevitably create turbulence around the cutter wheel, it is possible to improve the separation band by providing a rearwardly offset support surface for the separation band between the cutter and the opposing blade. can be protected from inadvertent removal. In this embodiment, the cutter provides some shielding effect on the separation strip.

0012

Embodiments Next, embodiments of the present invention will be described with reference to the drawings.

The web material 1 with a printed image is transferred via a floating table 2 from a rotating cutter wheel 3 having two cutter pairs consisting of parallel cutters 4a and 4b and a stationary opposing cutter 5 having one cutter 4c. The cross cutter is supplied with A series of suction and blow holes 9 are provided between the cutters 4a and 4b, which holes 9 form a radial passage 17 depending on the rotational position of the cutter wheel 3, as explained below.
can be connected alternately to a suction air source and a blowing air source through.

At the position of the cutter wheel 3 shown in FIG. 1, the cutter 4a, together with the cutter 4c, cuts a sheet 6 with a printed image from the web material 1, and this sheet 6 is placed on a floating table 7. It is discharged. Furthermore, the cutting strip 8 to be cut is held by a suction/blow hole 9 which is under negative pressure. When the cutter wheel 3 rotates further, the cutter 4b cuts the separation strip 8 together with the cutter 4c. This separation band 8 remains attached to the suction and blowing hole 9 until the suction and blowing hole 9 is separated from the suction air source and connected to the blowing air source. The connection changeover takes place after the cutter wheel 3 has made a minimum 1/4 turn and a maximum 1/2 turn, in particular 1/3 turn, from the cutting position.

In order to discharge the dislodged separation strip 8, a suction cover 12 is provided on the cutter wheel 3, which suction cover 12 is provided with a suction cover 12 by forming a blowing air nozzle 13 provided on the inside. , has a feeding action in the direction of arrows 11 and 14.

In order to provide the cutters 4a, 4b and the suction/blow holes 9, the cutter wheel 3 has legs 10;
Cutters 4a and 4b are fixed to this side surface with screws 21a and 21b. The cavity 22 allows easy access to the mounting screws 21a, 21b. The cavity 22 is covered by an outer shell 23. Legs 10
A suction/blow hole 9 is provided in the hole 9, which hole 9 consists of a suction opening 9a and a mounting screw 9b which holds it and is passed through in the axial direction. The axial passage of the mounting screw 9b communicates with a passage 17, which in turn communicates with the axial groove 16a of the rod 15 fitted in the center hole of the cutter wheel 3. In this example, two identical pairs of cutters are provided diametrically opposite, so that two axial passages 16a are fitted in the groove 18 and are closely closed to each other by a sealing member acted by an elastic tube. ,1
6b is provided on the rod 15.

As shown in FIGS. 4 and 5, pipe connection ports 27a and 27 are provided at the end faces of the two passages 16a and 16b.
b, which is in close contact with stationarily mounted distribution plates 25a, 25b having an inlet 26a and an outlet 26b. The inlet and outlet 26a, 26b are for suction and
When the blowing hole 9 is in the cutting position, this hole communicates with the inlet 26a for suction air (see the bottom of FIG. 4), and
When the blowing holes 9 are not in the cutting position, they are pivoted relative to each other so that they are in communication with the outlet 26b for blowing air (see top of FIG. 4). In that case, the inlet and outlet 26a, 26
The pivoting displacement b is carried out in such a way that the separating strip 8 is held for a sufficiently long time on the one hand, and is blown away quickly enough to be swept away on the other hand. This is the inlet and outlet 26a
, 26b must not be diametrically opposed.

The stationary distribution plates 25a, 25b have hollow journals 2 connected by conduits to a source of suction and blowing medium.
4a and 24b with screws. The stationary hollow journals 24a, 24b are supported on the hollow journal 3a of the cutter wheel 3 by bearings 28a, 28b. The pressing force necessary to seal between the distribution plate 25a and the pipe connections 27a, 27b is generated by the spring 30. This spring 30 is supported on the one hand in a threaded ring 29 fitted into the hollow journal 3a and on the other hand in a bearing 28b formed as an inclined spherical bearing 28b and fixed in the axial direction to the hollow journal 24b.

Next, the relationship in the case of the cross cutter shown in the embodiment will be explained using specific numbers.

100 each for suction and blowing air
A side passage compressor with mbar working pressure is used,
In that case, the resistance causes a pressure loss of about 50%. Each of the flow passages 16 has a cross section of about 1 cm2,
Its volume is 200cbcm including the connected hole 17
, to achieve a vacuum of 50 mbar below standard pressure requires 4 ms at a total resistivity of 12.5 when the suction opening 9a is closed, and for an open suction opening with a 2 mm hole in the mounting screw 10. In some cases, 8ms is required. At this time, the cutter stroke is 22.5° or 4
40 or 80 mm, corresponding to an angular travel of 5°. The opening and closing times of a 12.5 mm diameter hole with an eccentric position of 15 mm each last 8 ms for an angular travel of 45°. Therefore, in order to guarantee stable function, the time required to switch from the suction operation to the spray operation is exactly one of the cutter wheels 3 when the number of sheets is 30 per second, that is, when the rotation speed is 900 revolutions per minute. /
It's only 4 rotations shorter.

At a rotational speed of 900 revolutions per minute and a cutter wheel diameter of 210 mm, a centrifugal force of 180 g acts on the wide cutting strip 8 weighing 2 g. In the illustrated example, the holding force at the suction opening 9a with an internal diameter of 10 mm is 1250 g at a pitch of 30 mm;
The pushing-off force of the spray hole 9 with a diameter of 2 mm is 50 g. This large value of the suction and holding forces is such that the separation band 8 can be easily removed without air stagnation before the separation band 8 is pulled by the suction force behind the protective leading edge into the suction opening 9a located at the rear. Ensures that the leading edge is taken off the feed rate. This stagnation of air that becomes an obstacle at the leading edge of the separation band 8 is caused by the blown air in the gap between the cutter 4a and the cutter 4a.
, 4b, and cannot be removed by the air blown from the floating platform 2. The effective action of the blowing air occurs again only on the leading edge of the following sheet.

[0022]

As explained above, the present invention provides a suction/blow hole that can be operated alternately by negative pressure and blowing air via a valve control device depending on the rotational position of the cutter wheel. The valve control device makes it possible to increase the negative pressure and overpressure of the suction and blowing air source in the blowing hole, so that the cutting strip can be evacuated with high efficiency and without any problems, without requiring large expenditures. There is an effect that can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of a cross cutter of the present invention during a cutting operation.

FIG. 2 is an enlarged sectional view showing a pair of cutters constituting the cross cutter shown in FIG. 1;

FIG. 3 is a plan view of the pair of cutters shown in FIG. 2, viewed from below.

FIG. 4 is an explanatory diagram showing an air flow path inside a cutter wheel that constitutes the cross cutter shown in FIG. 1;

5 is a cross-sectional view along the cutter wheel rotation axis showing the structure of the end face side portion of the cutter wheel shown in FIG. 4. FIG.

[Explanation of symbols]

1 Web material 2 Floating table 3 Cutter wheels 4a, 4b, 4c Cutter 5 Opposing cutter 6 Sheet paper 7 Floating table 8 Separation band 9 Suction/blow hole 9a Suction opening 9b Mounting screw 10 Leg 11 Arrow 12 Suction cover 13 Blow air nozzle 14 Arrow 15 Rod 16a, 16b Passage 17 Passage 18 Groove 21a, 21b Screw 22 Cavity 23 Outer shell 24a, 24b Hollow journal 25a, 25b
Distribution plates 26a, 26b Inlet and outlet 27a, 27b
Pipe connection ports 28a, 28b Bearing 29 Screw ring 30 Spring

Claims (3)

[Claims] 1. A cutter wheel (3) equipped with a pair of parallel cutters (4a, 4b), a stationary opposing cutter (4c), and a cutter wheel (4a, 4b) that is provided with a pair of parallel cutters (4a, 4b);
) and cutter (4b) for the separation band (8),
a cross cutter for web material with printed images, comprising a removal device (9, 12) actuated by suction air, said removal device (9, 12) comprising a cutter (4a), a cutter (4b) of the respective pair of cutters; A suction/blow hole (9) is provided in between, and this suction/blow hole (9) is connected to a suction air source during cutting and is connected to a blow source in the rotation range turned to the cutting rotation position. a valve control device (27) via at least one passage (16a, 16b, 17) extending through said cutter wheel (3),
a, 27b, 25a, 25b, 26a, 26b), the suction/blow hole (9) can be connected depending on the angle of rotation of the rotating cutter wheel (3) and is pierced by blowing air. The separated separation band (8)
A suction cover (12) is provided around the cutter wheel (3) in the rotation range, in which case the valve control device (25a, 25b, 26a, 26b,
27a, 27b) are provided on said cutter wheel (3), and are connected to fixed and oppositely rotationally displaced inlets and outlets (26a, 26b) of the suction and blowing air source and to said suction and blowing holes (9). ) of the passage leading to and exiting from the
A cross cutter for web material with printed images, characterized in that it has at least one pipe connection port (27a, 27b) which alternately opens the inlet and outlet (26a, 26b). 2. The cutter wheel (3) is provided with an inlet (26b) on one end face side, an outlet (26a) on the other end face side, and a respective passageway (16a, 16b) on both end face sides. 2. The cross cutter according to claim 1, wherein the cross cutter has pipe connections (27a, 27b). 3. A cutter (4) for the separation band (8).
Cross cutter according to claim 1, characterized in that a rearwardly offset support surface is provided between a, 4b) and the blade opposite thereto.