EP0947320A1 - Method and means for reversing a sheet in a printing press - Google Patents

Abstract

The invention relates to a method and apparatus turning a sheet in a printing machine. More specifically, a swing arm is provided to grip a trailing edge of a sheet delivered on a first cylinder and transfer the gripped edge to a second cylinder. The invention provides low-outlay sheet-turning apparatus which provides smear-free sheet transportation. In conjunction with the swing arm, the second cylinder has secant-like flattened sections, or a non-circular cross-section, forming clearance areas within an outer circumference of the second cylinder as defined by a rotary path of radially outward portions of the second cylinder. In face-and-reverse printing mode, these clearances enable the swing arm to synchronously travel a sheet-feed path which intersects the circumference of the second cylinder. With this motion the swing arm draws the sheet from the first cylinder in a substantially tangential manner, avoiding dramatic curving of the sheet. The swing arm deposits the transferred edge of the sheet to a gripper on the second cylinder, which carries the sheet to a downstream cylinder. When the sheet is transferred onto the downstream cylinder, it is "turned over" relative to its initial orientation. In a face printing mode, the swing arm can be fixed in a position near the second cylinder, the swing arm having openings which deliver a flow of air against the sheet to assist in guiding the sheet onto the second cylinder.

Description

The invention relates to a method and device for turning a sheet in a printing press according to the generic terms of main and secondary claims.

A method and a device of this type is known from DE 27 56 507 A1 for a Rotary printing machine in series construction for the Schön- and Schön- and Reverse pressure known. A sheet on an intermediate drum is from a vibrating system, here called swivel gripper, is grasped on its rear edge and with this edge as a turned leading edge to a second intermediate drum transported further. The intermediate drums are full sheet guide cylinders Cylinder surface. The swivel gripper has mechanical grippers for removal and transporting the sheet. This solution is for a printing press suitable, the printing units each connected to several intermediate drums are. The swivel gripper is in particular between two intermediate drums arranged. To the swinging movement of the swivel gripper or Running through the gripper systems of an intermediate drum collisions with an adjacent one The circumference of the intermediate drum should be avoided Can be reduced in size temporarily during the swinging movement. Preferably points this drum on different shell segments, of which at least one provided with grippers is movable. The axis shaft of the swivel gripper is eccentric movable and synchronized with the rotational movement of the intermediate drum. When the swivel gripper is switched off, the printing press can be operated in straight printing.

The disadvantage here is that due to the large number of between the printing units arranged drums and the movable shell segments on a drum this printing press is very complex. Furthermore is between the drums and the swivel gripper requires a sheet guide because the sheet is on a strongly curved trajectory. Especially when rewinding of the swivel gripper there is a risk of greasing if the Swivel gripper comes into contact with the rear area of the arch.

A turning device of this type is also from DE 26 33 183 C2 for a sheet-fed rotary printing press known. This printing machine has i.a. one with a turning drum cooperating transfer drum, wherein between Transfer drum and turning drum a removal device is arranged. In one embodiment, the removal device comprises a gripper device, which the sheet turned on the turning drum with its original Traces the rear edge as the front edge to the same transfer drum from which the sheet was fed to the turning drum.

The disadvantage here is that in addition to the required sheet guiding cylinders, like printing cylinder and transfer drum, additionally a reversing drum with assigned Acceptance device is required.

According to DE 36 02 084 C2 is a sheet transfer drum between printing units known from rotary printing presses between at least two gripper bridges formed essentially as a secant within the drum circumference Has guiding surfaces (flattening). The guide surfaces are intended as guide vanes serve, which generate an air jam in printing operation, the respective sheet with the printed surface away from the guiding surfaces in order to create a lubricating and to create doubling-free sheet guidance.

From DE-AS 12 62 294 is a sheet turning device with a between the Printing cylinders of two printing units of a multi-color sheet-fed rotary printing press arranged transfer cylinder known. When turning, the bow on the rear edge of suction pads as the first gripper system of the transfer cylinder sucked in. The first gripper system swings on the transfer cylinder in a free space and passes the bow to one also on the Transfer cylinder arranged second gripper system. The second gripper system leads the arch so turned in the gripper closure until delivery a downstream printing cylinder. The disadvantage here is that for the transfer cylinder a considerable amount of parts and a complex control the gripper systems is required.

The invention has for its object a method and an apparatus of the type described at the outset, which avoid the disadvantages mentioned, which, in particular, permits a turn with little effort and allows smear-free sheet transport.

The object is achieved by the training features of claim 1 and 7 solved. Further training results from the subclaims.

The solution according to the invention is advantageous for rotary printing presses in Suitable in series, which one or three between the printing units Have transfer cylinders (transfer drums) as sheet guide cylinders, wherein at least one transfer cylinder within the cylinder circumference essentially is limited by secants. Through a transfer cylinder of this kind is inside of the cylinder circumference, a space, preferably created as a segment of a circle, in which a bow-leading vibration system is movable. By such a movement of the oscillating system, a smear-free sheet transport can be realized, because the arc is noticeably less curved and essentially tangential from upstream sheet guide cylinder, preferably the impression cylinder, removable is. A slender sheet run can thus be achieved since the sheet has no essential Curvature from the upstream sheet guide cylinder to the following one Bow guide cylinder can be passed. It is in preferred training the swing system as a bow guide, especially with blown air support, usable.

It is also advantageous that only a small number of transfer cylinders between the printing units and therefore the number of transfer stations from printing unit to printing unit is low. The one according to the invention is preferred Solution can be used in rotary printing machines, which between two printing units, the term also a coating unit or a processing station includes, only have one transfer cylinder each. At least the transfer cylinder assigned to the vibration system is within the cylinder circumference between gripper systems limited by secants.

Finally, another advantage is based on the fact that a transfer cylinder limited by secants can be used as a sheet guiding cylinder for straight printing (one-sided printing) and for face and reverse printing (two-sided printing). This means that no separate reversing cylinders are required, and in existing rotary printing presses with corresponding transfer cylinders for straight printing, the oscillating system can be retrofitted with little effort and thus the rotary printing press can be expanded to include perfecting.
Ultimately, regardless of the desired operating mode, the sheet-guiding cylinders (as a printing cylinder in the printing unit and as a transfer cylinder in the transfer area) can each be carried out uniformly between the printing units, so that the use of one or more reversing drums is no longer necessary. This also eliminates the need to separate the drive wheel train (when changing the format or changing the operating mode). The vibration system can be driven separately or can be switched into the existing drive wheel train by means of a coupling.

Fig. 1

eine Bogenrotationsdruckmaschine,

Fig. 2

eine Wendeeinrichtung mit Schwingsystem,

Fig. 3

ein Detail eines Schwingsystems.

The invention will be explained in more detail using an exemplary embodiment. The following schematically show:

Fig. 1

a sheet-fed rotary printing press,

Fig. 2

a turning device with vibration system,

Fig. 3

a detail of a vibrating system.

1 shows a variant of a sheet-fed rotary printing press in a row construction.
Each printing unit shown is formed from a first sheet guide cylinder 1, here a printing cylinder, symmetrically distributed around the circumference of gripper systems 4 and a blanket cylinder 22. The plate cylinder as well as the inking unit and, if applicable, the dampening unit will not be discussed further here.
In a further embodiment, instead of the blanket cylinder 22, a forme cylinder can be used, for example as a carrier for a flexible high-pressure mold in a coating unit. Between the printing units, a sheet guide cylinder 2 is arranged as a transfer cylinder for sheet transport, which has gripper systems 4 arranged symmetrically on the circumference and, within a flight circle 3 of the gripper systems 4, has flattenings 21 which essentially each correspond to a secant 15. The flats 21 can also be slightly curved (concave or convex). There is therefore a free space, preferably a circular segment 16, between the flats 21 and the flight circle 3. The sheet guiding cylinders 1, 2 are double in size, based on the rubber blanket cylinder 22 with a single large diameter. In the present example, each sheet guide cylinder 1, 2 thus has two gripper systems 4 arranged symmetrically around the circumference. In the area between the two sheet guide cylinders 1, 2, a vibrating system 7 is arranged below these sheet guide cylinders 1, 2.

elektronische Kurvenscheibe" (programmierbarer Servoantrieb). In Verbindung mit dem Antrieb 8 wird über die Lagerung 19 die Bewegung des Schwingsystems 7 mechanisch (Exzenter, Kurvengetriebe) oder elektrisch (elektronische Kurvenscheibe) erzeugt. Das Kurvengesetz ist derart ausgebildet ist, daß das Schwingsystem 7 in den Freiraum des zweiten Bogenführungszylinders 2 bewegbar ist. Dabei ist die Lagerung 19 bevorzugt innerhalb des Schwingsystems 7 oder achsparallel zum Antrieb 8 angeordnet. Der Antrieb 8 ist separat steuerbar oder mit dem Antriebsräderzug über eine Kupplung koppelbar. Abhängig von den zu verarbeitenden Bogen 20 ist über die Lagerung 19 die Formatverstellung des Schwingsystems 7 mechanisch oder elektrisch stufenlos durchführbar.The vibration system 7 is rotatably received in a bearing 19 and is functionally connected to a drive 8. The bearing 19 is, for example, an eccentric, a cam mechanism or a

electronic cam "(programmable servo drive). In connection with the drive 8, the movement of the vibration system 7 is generated mechanically (eccentric, cam mechanism) or electrically (electronic cam) via the bearing 19. The curve law is designed such that the vibration system 7 in the free space of the second sheet guide cylinder 2. The bearing 19 is preferably arranged within the oscillation system 7 or axially parallel to the drive 8. The drive 8 can be controlled separately or can be coupled to the drive wheel train via a clutch the storage 19 the format adjustment of the vibration system 7 mechanically or electrically continuously.

Furthermore, the oscillation system 7 is movable on a guide track 9, which is formed by a forward track 18 and a return track 17. The vibration system 7 has a swing arm 11 which is connected to the bearing 19. On the swing arm 11, a suction bar 10 is arranged at the end, which is functionally connected on the line side to a pneumatic system that generates, preferably switchable, pneumatic air.
In a preferred further development, the swing arm 11 has a plurality of openings 12 to support the sheet guide, which openings are connected on the line side to a pneumatic system which generates, preferably switchable, pneumatic air. The blown air supply and the openings 12 are preferably integrated in the swing arm 11 or arranged on this swing arm 11. Squeegee 10 and openings 12 are assigned to the sheet guide cylinder 1 adjacent to the swing arm 11, the squeegee 10 preferably being format-adjustable, depending on the format length of the substrates to be processed. The pneumatically actuated openings 12 can be used to support the sheet guide.

In a further embodiment, the end of the swing arm 11 in the area of the Squeegee 10 arranged a gripper system 4 with grippers 13, the Squeegee 10 serves as an impact bar. The suction bar 10 is used for suction a bow 20 and the gripper system 4 with grippers 13 serves the additional Positional fixation of the bow 20 during the swinging movement. This additional Training is preferred for sheet-like substrates with higher basis weights, in particular cardboard, cardboard or sheet metal can be used. For the period of the suction of the respective sheet 20 in the takeover area 5 is Squeegee 10 free, i.e. the grippers 13 are pivoted away. The movement of the Gripper 13 is preferably carried out via one or more control cams with one corresponding motion law.

The second sheet guide cylinder is preferred in the conveying direction 14 after the transfer region 6 2 assigned a sheet guiding device (not shown). This sheet guiding device is outside the flight circle 3 at a short distance arranged to the sheet guide cylinder 2 and extends approximately to the takeover area of the downstream (third) sheet guiding cylinder 1. Where is the sheet guide device preferably as a continuous guide surface Openings designed as air nozzles in a flow channel, these openings with blowing air and / or suction air.

For the operating mode "The swing system 7, especially the swing arm 11, can be fixed in the transfer area 6 and forms a sheet guide system with the downstream sheet guiding device, which serves to guide the sheet on the second sheet guide cylinder 2. The suction bar 10 and the blowing openings 12 on the swing arm 11 are with blowing air or suction air Can be supplied via a common or separate, switchable pneumatic system.

For the operating mode Fine and reverse printing ", the openings 12 of the swing arm 11 can be acted upon with blown air at least in the conveying direction 14, preferably on the route of the guide curve 9 from the take-over area 5 to the transfer area 6, in order to support the sheet guidance.

In addition to the described arrangement of a vibration system 7 (between two Printing units) is also a multiple arrangement of vibration systems 7 between the lined up printing units can be realized. The sheet guiding cylinder 1, 2 are as a printing cylinder and transfer cylinder or storage drum and transfer drum Executable within the printing press.

The mode of operation is as follows: an arc 20 is formed on the closed surface of the first sheet guide cylinder 1 in the gripper closure in the conveying direction 14 guided. The front edge of the sheet 20 is in the gripper system 4 by means of Grippers 13 fixed in position.

In straight printing, the sheet 20 is at the tangent point 23 with the leading edge from Gripper system 4 of the first sheet guide cylinder 1 in the conveying direction 14 to the Pass gripper systems 4 of the second sheet guide cylinder 2. The corresponding Gripper system 4 of the second sheet guide cylinder 2 now leads the Sheet 20 and passes this in the conveying direction 14 to the (third) sheet guide cylinder 1 of the following printing unit. The vibration system 7 is in Transfer area 6 fixed in position (at a short distance from the second sheet guide cylinder 2) and is used for the preferably pneumatically supported sheet guide of the second sheet guide cylinder 2 transported in the conveying direction 14 Sheet 20

In front and back at machine speed, the one at first Sheet guide cylinder 1 lying, printed sheet 20 over the tangent point 23 led out. After / after the trailing edge of the arc 20 the tangent point 23 has passed, the end of the sheet 20 in the takeover area 5 of the Vibration system 7 by means of suction bar 10 by suction through its openings detected, the vibration system 7 on an arc in the direction of rotation of the first Bow guide cylinder 1 is moved. Then the speed of the Vibration system 7 decelerated to zero, then receives the vibration system 7 a reversal of movement and the sheet 20 is on the guideway 9 from Vibration system 7 guided in the direction of the second sheet guide cylinder 2 and with its edge - which is now a turned front edge - in the transfer area 6 passed on to the downstream second sheet guide cylinder 2. The gripper system 4 in the second sheet guide cylinder 2 detects the sheet 20 by means of grippers 13 and transfers them to the gripper system in conveying direction 14 4 of the (third) sheet guiding cylinder 1 in the subsequent printing unit. The vibrating system 7 then moves away from the second sheet guiding cylinder 2, is accelerated (towards the upstream sheet guiding cylinder 1) and the next sheet brought up on the first sheet guide cylinder 1 is sucked in.

The activated vibration system 7 can be driven separately from the drive 8 or via the drive wheel train of the machine drive. The guideway 9 for the oscillation system 7 is designed such that this oscillation system 7 intersects the flight circle 3 of the second sheet guiding cylinder 2.
The oscillation system 7 is preferably movable on a forward path 18 intersecting the flight circle 3 of the second sheet guide cylinder 2 and a return path 17 running outside the flight circle 3 (FIG. 2). This design of the leading path 18 has the advantage that the sheet 20 is essentially tangentially stretched (without compressing) from the upstream sheet guiding cylinder 1 and the swing arm 11 can be moved back without lubrication underneath the rear area of the sheet 20 on the return path 17 to the takeover area 5 .

The swing arm 11 (with bow 20) dips in the conveying direction 14 before Gripper system 4 of the second sheet guiding cylinder 2 - the flight circle 3 cutting - into the free space preferably formed as a circular segment 16, emerges from the free space cutting flight circle 3 and goes in the transfer area 6 in the waiting position until the trailing gripper system 4 of the (second) Sheet guiding cylinder 2 is in the transfer area 6. Sheet 20 is handed over and the swing arm 11 moves at a distance to the flight circle 3 from the second Bow guide cylinder 2, pauses briefly and then swings below of the rear sheet area on the return path 17 to the takeover area 5 back. The swing arm 11 preferably cuts the advance path 18 and goes into waiting position in takeover area 5. The first sheet guide cylinder 1 promotes the following bow 20 via the tangent point 23 on the swing arm 11 over, the swing arm 11 in the conveying direction 14 to the sheet guide cylinder 1 moves in unison until the rear edge or the rear area of the Bow 20 sucked by the suction bar 10 on the swing arm 11 and on the leader 18 is brought.

Alternatively, the oscillation system 7 is on the flight circle 3 of the second sheet guide cylinder 2 intersecting return path 17 and the outside of the flight circle 3 running leading path 18 movable.

The oscillation system 7 is also on the flight circle 3 of the second arc guide cylinder 2 intersecting leading path 18 and the intersecting the flight circle 3 Return path 17 movable.

The formation of the sheet guide cylinder 1, 2 is not based on the embodiment described confined with double large cylinders. Rather, they are also suitable Sheet guiding cylinders with multiple large diameters, e.g. triple or four times the diameter. There is also a combination of multiple same size sheet guide cylinders 1 and 2 included. Likewise are Combinations of a double-sized sheet guide cylinder 1 or 2 and a triple-sized sheet guide cylinder 1 or 2 and a triple large sheet guide cylinder 1 or 2 and a fourfold sheet guide cylinder 1 or 2 possible.

List of reference symbols

1

Bow guide cylinder

2nd

Bow guide cylinder

3rd

Flight circle

4th

Gripper system

5

Takeover area

6

Transfer area

7

Vibrating system

8th

drive

9

Guideway

10th

Squeegee

11

Swing arm

12th

Blow opening

13

Gripper

14

Direction of conveyance

15

secant

16

Circle segment

17th

Return path

18th

Preliminary run

19th

storage

20th

bow

21

Flattening

22

Blanket cylinder / forme cylinder

23

Tangent point

Claims (19)

Method for turning a sheet in a printing press, wherein the sheet guided on a first sheet guide cylinder designed with at least one gripper system is taken over by a rotatably mounted oscillating system on its rear edge and transferred with this edge as a front edge to a second sheet guide cylinder arranged downstream,
characterized,
that the oscillating system is moved on a guideway which intersects the flight circle of the second sheet guiding cylinder. Method according to claim 1,
characterized,
that the oscillating system is moved on a leading path of the guideway which intersects the flight circle of the second sheet guiding cylinder and on a return path of the guideway which runs outside the flying circle. Method according to claim 1,
characterized,
that the oscillating system is moved on a return path of the guideway that intersects the trajectory of the second sheet guiding cylinder and on a lead path of the guideway that runs outside the trajectory. Method according to claim 1,
characterized,
that the vibration system is moved on a leading path intersecting the flight circle of the second sheet guiding cylinder and a return path of the guideway. Method according to claim 1,
characterized,
that the end of a sheet guided on the first sheet guide cylinder is sucked in with the vibrating system at machine speed, that the vibrating system is moved on a circular arc in the direction of rotation of the first sheet guide cylinder, then the speed of the vibrating system is decelerated to zero and then the vibrating system receives a reversal of movement and on Machine speed is accelerated and the sheet is transferred to the second sheet guide cylinder and then the vibrating system moves away from the second sheet guide cylinder, is accelerated and the next sheet brought up on the first sheet guide cylinder is sucked in. Method according to claim 5,
characterized,
that the bow is fixed in position on both sides of the oscillating system at the front edge. Device for turning a sheet in a printing press, wherein the sheet guided on a first sheet guide cylinder with at least one gripper bridge can be taken over by a rotatably mounted oscillating system on its rear edge and can be transferred with this edge as a front edge to a downstream second sheet guide cylinder,
characterized,
that the second sheet guide cylinder (2) symmetrically arranged on the circumference gripper bridges (4) and within the circumference between the gripper bridges (4) has essentially secant flats (21) and that between the first sheet guide cylinder (1) and the second sheet guide cylinder (2) is arranged in a bearing (19) in a free movement space (19) formed by the flats (21). Device according to claim 7,
characterized,
that the bearing (19) is an eccentric bearing. Device according to claim 7,
characterized,
that the bearing (19) is a bearing controlled by cam gear. Device according to claim 7,
characterized,
that the storage (19) a means

electronic cam "controlled storage is. Device according to claim 7,
characterized,
that the first sheet guide cylinder (1) is a printing cylinder and the second sheet guide cylinder (2) is a transfer cylinder. Device according to claim 7,
characterized,
that the first sheet guide cylinder (1) is a storage drum and the second sheet guide cylinder (2) is a transfer cylinder. Device according to claim 7,
characterized,
that the sheet guide cylinders (1, 2) are at least twice as large in relation to a single-sized blanket cylinder (22). Device according to claim 7,
characterized,
that the vibration system (7) has a suction bar (10) which is functionally connected to a pneumatic system. Device according to claim 13,
characterized,
that the squeegee (10) is adjustable depending on the format. Device according to claims 7 and 13,
characterized,
that the vibration system (7) has blowing openings (12) for the sheet guide. Device according to claim 13,
characterized,
that outside, at a short distance from the second sheet guiding cylinder (2), a sheet guiding device is arranged in the conveying direction (14) after the transfer area (6). Device according to claim 7,
characterized,
that the vibration system (7) in the operating mode Fine print "in the transfer area (6) of the sheet guiding cylinder (2) can be fixed in position and is a sheet guiding device. Device according to claim 18,
characterized,
that the vibration system (7) is a pneumatically actuated sheet guide device.

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