EP1122064B1 - Method and device for sheet guide in a rotary press - Google Patents

Abstract

In the direction (8) of the sheets' travel in front of the printing zone is a nozzle system (7) formed of annular gap nozzles (16) forming a blower and fixed to a cross-bar (15) attached to a frame. At least several annular gap nozzles point towards the rubber blanket/ form cylinder (11) and are connected to a distributor duct, a feeder duct and an on-off valve with a pressurized air source.

Description

The invention relates to a method and a device for sheet guiding in a rotary printing machine according to claims 1 and 6.

[State of the art]

A sheet guiding apparatus is known from EP 0 306 682 A2 known. The device consists essentially of two acted upon with blowing air blowing strips, which are arranged axially parallel before and after the pressure zone formed by a blanket cylinder and a printing cylinder over the cylinder width. The front in the conveying direction blowing bar is arranged in the zwickelförmigen space above the incoming sheet between blanket cylinder and impression cylinder. The blast air flow is directed to the blanket cylinder, in the print zone itself and on the top of the sheet guided in the gripper closure on the printing cylinder. The arranged in the conveying direction after the pressure zone rear blowing bar achieves a Blasluftstrom, which is directed against the conveying direction on the top of the sheet guided on the printing cylinder and on the blanket cylinder. In this case, a blow bar by means of a controllable valve in the phase between the start of printing and the end of the sheet material by means of pulsed blowing air is operable.

The invention primarily describes the sheet guiding device in the printing operation (pressure on position). It is also in the printing practice another operating position in use, such that when the blanket cylinder (pressure off position) of the blast air operation is maintained, for example, when controlling the paper path or if a printing unit is not involved in the pressure. The printing material is then conveyed in the gripper closure on the printing cylinder through the printing gap (contactless to the inactive blanket cylinder) by means of blowing air through the appropriate printing unit.

Out DE 43 18 777 C2 is a sheet guiding device for a not involved in printing printing unit with existing gap between the blanket cylinder and impression cylinder known. For this particular operating position, in each case a blower tube with nozzles is arranged before and after the pressure zone, wherein in each case a nozzle of the upstream blowpipe faces a nozzle of the downstream blowpipe. In this case, the nozzles of the upstream blowpipe blow a constant blown air against the blanket cylinder, which is deflected in front of the print zone, and the nozzles of the downstream blowpipe blow a constant blown air against the printing cylinder, so that the sheet material is struck against the conveying direction.

In order to achieve a smoothing of sheets, according to another known embodiment according to DE 39 20 730 C2 at least one nozzle used, which directs an air jet on the sheet-shaped substrate and thereby achieves a coating effect. The nozzles are mounted in front of the nip about an axis parallel to the axis of the printing cylinder pendelbar and can be coupled with a drive, which in the working cycle of the printing press, the blowing nozzle moves back and forth in the conveying direction of the printing material. As a result of the oscillatory movement, a relaxation and uniform placement of the sheet material on the sheet guiding cylinder, especially for thin substrates with low basis weight, certainly not guaranteed. In this case, the air flow of the nozzles in the working cycle of the printing machines can be controlled in one embodiment.

Out DE 195 30 039 C2 and DE 197 00 370 A1 are blowing devices for supporting the bowing known, with each specially trained blowpipe cyclically with blown air can be acted upon.

A disadvantage is the relatively high air consumption of such sheet guiding devices. A further disadvantage is that delays occur through the volume of the blower tubes in cyclically acted sheet guiding devices, so that the sheet guiding devices react relatively sluggishly during cyclic operation, in particular at higher machine speeds.

Out DE-A 197 53 089 a sheet guiding device is known, which extends in the conveying direction of the sheet material before and after a printing nip box-shaped at least over the minimum format width. The sheet guiding device is coupled to a pneumatic system for the purpose of supplying blown air, has a plurality of chambers for receiving air and has openings for the Blasluftaustritt. In this case, the leaking blast air has a gradient with respect to the pressure energy. The sheet guiding device is used in the printing operation with rubber blanket / forme cylinder employed in the printing zone or for a blanket / forme cylinder not involved in the printing with a gap present between it and a sheet guiding cylinder.

According to US-A-4,384,524 a device for spreading sheet material on a printing cylinder of a printing machine is known. In this case, the printing cylinder leads the resting sheet material at a leading edge of the sheet in the gripper closure. At a distance above the pressure cylinder two mutually spaced at a distance blowpipes are provided. The blowpipes extend in the axial direction over the full cylinder width and are at least partially covered by an air chamber forming an air cushion cover plate.

Out US 5,816,155 a sheet guiding device for printing presses is known, which has nozzles penetrated with guide surfaces. The nozzles can be acted upon with blown air and in some areas optionally with suction air and serve to Schwebeführung the respective arc on an air cushion along the fins.

In DE-A-197 21 390 is a device for non-contact sheet guiding in a printing press described in which are arranged in a sheet guide Blasluftdüsen with an inclined from the Bogenleitfläche downwardly directed air duct. The bow is guided floating on an air cushion.

OBJECT OF THE INVENTION

The invention has for its object a method and apparatus for sheet guiding in a rotary printing machine to avoid the disadvantages mentioned, which allow a more uniform guidance of the printing material on a sheet guiding cylinder, in particular a printing cylinder, and have a more favorable energy consumption of compressed air.

The object is solved by the training features of claims 1 and 6. Further developments emerge from the subclaims.

[Examples]

A first advantage of the invention is due to the fact that the device has a nozzle system, which is formed in the region of a print zone by a plurality of arranged over the maximum format width of the printing material annular gap nozzles. Such a nozzle system can be operated with compressed air, which emerges at very high speed at the annular gap nozzles. This nozzle system entrains large amounts of ambient air, which emerges bundled with the compressed air as jet flow from the annular gap nozzles and on the sheet material works. Since the annular gaps of the nozzle system are very narrow and preferably adjustable and in addition the existing ambient air is used, the energy consumption of compressed air is relatively low. Since the annular gaps are preferably adjustable, the jet pressure acting on the printing material can be adjusted taking into account the weight per unit area and / or the stiffness and / or the Drucksujets the sheet material. This results in adjustable annular gap nozzles the advantage that considered across the format width different jet flows act on the sheet material.

A further advantage is that the nozzle system generates a low sound level, so that the noise load for the operator or the environment can be reduced.

At least in the conveying direction of an arcuate printing material is arranged in front of a blanket from the blanket / forme cylinder and the sheet guiding cylinder, preferably the printing cylinder, a printing device, a sheet guiding device with a cyclically operable nozzle system. This device has at least in zwickelförmigem space in the conveying direction of the sheet-shaped printing material in front of the printing zone axially parallel to the sheet guiding cylinder arranged nozzle system with annular gap nozzles, which is in functional communication with a compressed air system and a device for timing control, eg a switching valve. The nozzle system arranged in front of the printing gap is preferably arranged with its flow direction completely or partially directed onto the lateral surface of the blanket cylinder / forme cylinder.

Another advantage is that in the control of clocked compressed air, the sheet format is taken into account, such that a Unterblasen the sheet trailing edge (end of the sheet) on the sheet guiding cylinder by a nozzle system regardless of the respective operating position (pressure on position, pressure off position ) is avoidable. The device for controlling the timing of the compressed air is preferably in functional connection with a central machine control. By means of this machine control, the cycle operation of the nozzle system is preferably format-dependent, preferably angularly correlated.
A further advantage is that the nozzle system in the cycled compressed air operation is responsive controllable because short switching times can be realized.

Finally, it is advantageous that the nozzle system has a low energy consumption of compressed air. By means of the nozzles compressed air at high speed can be achieved, which entrains large amounts of ambient air and thus a bundled air flow with high jet pressure as a reinforcing effect can be generated. By sharing the existing ambient air a favorable energy consumption of compressed air is achieved.

In another embodiment, in addition to the arranged in the conveying direction before the printing zone sheet guiding device another device for sheet guiding mirror image analogous to the upstream sheet guiding device with a nozzle system with annular nozzle, a device for timing control, such as a switching valve, and a compressed air system in functional connection. These annular gap nozzles of the nozzle system are thereby directed to the lateral surface of the sheet guiding cylinder (printing cylinder) and serve to guide the printing material when leaving the print zone.

A further advantage is that the nozzle systems are arranged pivotably on a traverse and in the axial direction of the traverse slidably.

The invention will be explained in more detail using an exemplary embodiment.

Fig. 1

eine Bogenrotationsdruckmaschine (Ausschnitt),

Fig. 2

eine Vorrichtung zur Bogenführung im Bereich eines Druckspaltes (Seitenansicht),

Fig. 3

eine Vorrichtung zur Bogenführung in Längsansicht,

Fig. 4

eine erste Ausbildung einer Düse,

Fig. 5

eine zweite Ausbildung einer Düse.

Showing:

Fig. 1

a sheet-fed rotary printing press (detail),

Fig. 2

a device for sheet guiding in the region of a printing nip (side view),

Fig. 3

a device for bowing in longitudinal view,

Fig. 4

a first embodiment of a nozzle,

Fig. 5

a second embodiment of a nozzle.

A sheet-fed rotary printing machine is according to FIG. 1 shown in rows. In this case, several printing units 1 are lined up for the multi-color printing with sheet guiding cylinders and interconnected with printing cylinders 5 and transfer cylinders 4 and turning systems and have sheet holding systems, eg gripper systems, vacuum systems, for sheet transport.

According to FIG. 1 a section of such a printing machine for inline finishing is shown. Only one last printing unit 1 with a plate cylinder 10, a blanket cylinder 11 and the impression cylinder 5 is shown as a sheet guiding cylinder. The plate cylinder 10 is associated with an inking unit and possibly a dampening unit, which will not be discussed in detail here.
The printing unit 1 is downstream of a first coating unit 3 in the conveying direction 8, which is formed by a forme cylinder 11, an applicator roller 12 and a metering system 13, for example a chambered doctor blade. The impression cylinder 5 is in turn associated with the forme cylinder 11. The first coating unit 3 is a dryer device 14, for example, an infrared dryer, an adjacent printing cylinder 5 or an adjacent transfer cylinder 4 assigned downstream. The drying device 14 follows in the conveying direction 8, a second coating unit 3 with forme cylinder 11, applicator roller 12 and a metering 13. The printing cylinder 5 of the printing units 1, Lackwerke 3 and the dryer 14 are interconnected by means of transfer cylinder 4 for sheet transport. The second coating unit 3 follows in the conveying direction 8, a boom 2, which feeds the sheet-shaped substrate by means of rotating conveyor systems 6 in a known manner to a delivery pile and deposits there.

In the area of a printing zone 29 formed by a blanket / forme cylinder 11 and a sheet guiding cylinder 5 of a printing unit 1 and / or at least one coating unit 3, an upstream nozzle system 7 is arranged in the conveying direction 8 in front of the printing zone 29. In the conveying direction 8, downstream of the pressure zone 29, a downstream nozzle system 9 is preferably mirror-inverted (Preferably identical) arranged to the nozzle system 7.

The nozzle systems 7, 9 extend axially parallel in the longitudinal direction over the width of the sheet guiding cylinder, here the printing cylinder 5, and are formed from a plurality of annular gap nozzles 16. The arrangement of the annular gap nozzles 16 in the upstream nozzle system 7 is for the arrangement of the annular gap nozzles 16 in the downstream nozzle system of any kind.

According to the invention, the annular gap nozzles 16 of the upstream nozzle system 7 point in the direction of the blanket / form cylinder 11, and the annular gap nozzles 16 of the downstream nozzle system 9 point in the direction of the pressure cylinder 5.

In an embodiment, the annular gap nozzles 16 of the upstream nozzle system 7 point exclusively in the direction of the pressure cylinder 5. Alternatively, the annular gap nozzles 16 of the nozzle system 7 point in the direction of the blanket / forme cylinder 11 and in the direction of the impression cylinder 5. In the latter embodiment, the proportion of the / Forme cylinder 11 facing annular gap nozzles 16. At least one annular nozzle 16 is directed to the sheet guiding cylinder 5.
In a further embodiment, the majority of the annular gap nozzles 16 is directed against the blanket / form cylinder 11 and a lesser proportion of the annular gap nozzles 16 points in the direction of pressure zone 29. Alternatively, the vast majority directed against the blanket / forme cylinder 11 and a share of Annular gap nozzles 16 is directed in the direction of the pressure zone 29 and on the sheet guiding cylinder 5.

The annular gap nozzles 16 are pivotally mounted on a fixed in the side frames 21 traverse 15 about the axis and displaceably arranged in the axial direction. The Annular gap nozzles 16 of each nozzle system 7, 9 are each operatively connected to a distribution channel 17. The distribution channel 17 is in functional connection with a feed channel 18, which preferably opens in the middle region. The feed channel 18 is in functional connection with a compressed air source 20, wherein for each nozzle system 7 or 9, a device for clock control, preferably a controllable switching valve 19, is connected in between.

In the FIGS. 4 and 5 are annular gap nozzles 16 shown in their basic structure. It shows FIG. 4 an annular gap nozzle 16 with an externally arranged annular gap 22, however, shows FIG. 5 an annular gap nozzle 16 with an annular gap 22 arranged inside.

The annular gap nozzle 16 according to FIG. 4 has a base body 28 with a channel 30 which is in operative connection via the distribution channel 17 with the compressed air source 20. On the base body 28, a cone 25 is releasably secured, for example, screwed onto the base body 28. Between the base body 28 and the cone 25 an outer annular gap 22 is arranged, which is in operative connection with the channel 30 in the main body 28. Preferably, the cone 25 is releasably connected to the base body 28 by means of thread 32. About the thread 32 is self-locking or finely metered adjustable by means of stop the annular gap 22 in its cross section.

In FIG. 5 The base body 28 also has a channel 30, which is in functional connection via the distributor channel 17 with the compressed air source 20. Within the base body 28, an insert element 27 is detachably fastened, for example screwed to the base body 28. Between the base body 28 and the insert member 27, an inner annular gap 22 is arranged, which communicates with the channel 30 in the main body 28 is in functional connection. Preferably, the insert element 27 is releasably connected to the main body 28 by means of thread 32 self-locking or by means of stop. About the thread 32 of the annular gap 22 is finely metered in its cross section adjustable. The main body 28 also has an intake opening 31 for the ambient air 24, which is in operative connection with a centrally disposed within the insert element 27, with the annular gap 22 in functional connection channel.

The nozzle systems 7.9 are optionally with annular gap nozzles 16 according to the Fig. 4 and / or 5 executable.

The operation of the annular gap nozzles 16 is as follows:
Compressed air is continuously supplied from the compressed air source 20 to the controllable switching valve 19 of the respective nozzle system 7 or 9. Compressed air is supplied from the compressed air source 20 via the feed channel 18 and the distributor channel 17 into the channel 30 of the annular gap nozzle 16, and within the channel 30 the compressed air is distributed and passes through the annular gap 22.

According to FIG. 4 occurs a gap flow 23 after the annular gap 22, which follows the contour of the cone 25 due to the Coanda effect. In this case, the ambient air 24 is entrained to a high degree and at the top of the cone 25 dissolves a bundled flow 23 and ambient air 24 bundled jet flow 26 with high jet pressure to support the bowing.

According to FIG. 5 remains after passing through the annular gap 22, the gap flow 23 in the channel 30 of the insert element 27. Since the channel 30 is coupled to the suction port 31 of the main body 28, via the intake port 31, the ambient air 24 is highly entrained in the channel 30 and exits at the end of the channel 30 as a jet stream 26 (formed from gap flow 23 and ambient air 24) with high jet pressure to assist bowing.

The working method of the nozzle systems 7, 9 is as follows. The first switching valve 19 for the upstream nozzle system 7 controls the incident on the sheet material jet flow 26 such that only in the phase between the beginning and End of each guided on the sheet guiding cylinder (pressure cylinder 5) sheet material, the jet stream 26 from the annular gap nozzles 16 in the nozzle system 7 exits (clock mode). If the end of the sheet material passes through the printing nip 29, the jet stream 26 is interrupted immediately.

The jet flow 26 is directed at least against the blanket / forme cylinder 11. In a development, the jet flow 26 is at least one annular nozzle 16 of the nozzle system 7 against the sheet guiding cylinder, here the impression cylinder 5, directed. Alternatively, the jet flow 26 of at least one annular gap nozzle 16 may also be directed into the pressure zone 29. The cyclic operation of the nozzle system 7 is realized in the printing operation when hired blanket / form cylinder 11 or a blanket / forme cylinder 11 not involved in the pressure with a gap in the print zone 29 between blanket and forme cylinder 11 and the sheet guiding cylinder 5.

If a pressure system 29 downstream nozzle system 9 is provided, so in synchronism with the interrupted jet flow 26 of the upstream nozzle system 7, the compressed air on the preferably coupled to a machine control, second controllable switching valve 19 is supplied to the nozzle system 9, such that a second jet flow 26 in the nozzle system 9 between the beginning and end of a guided on a sheet guiding cylinder (pressure cylinder 5) sheet material, in particular to the end of the sheet material on this incident. The second jet flow 26 of the annular gap nozzles 16 is directed against the sheet guiding cylinder, here the impression cylinder 5.

In a development, the jet flow 26 of the nozzle system 7 arranged in front of the pressure zone 29 is directed at least against the blanket / forme cylinder 11 and exits in the cycle operation in the phase between the center and the end of the sheet material.
In a further embodiment, the second jet flow 26 of the arranged after the pressure zone 29 nozzle system 9 against the sheet guiding cylinder, here the impression cylinder 5, directed and exits in the cycle operation in the phase between the center and end of the sheet material.

In a further embodiment, the pressure zones 29 upstream and downstream nozzle systems 7,9 are combined and operable. In this case, at least one directed against the blanket / forme cylinder 11 jet flow 26 intermittently from the nozzle system 7 and directed against the sheet guiding cylinder (pressure cylinder 5) second jet stream 26 emerges intermittently from the nozzle system 9.
This mode of operation is in the printing operation when employed blanket / forme cylinder 11 or not involved in the pressure blanket / forme cylinder 11 with a gap in the print zone 29 between blanket / forme cylinder 11 and the sheet guiding cylinder 5 realized to the sheet guide on the sheet guiding cylinder 5 guided sheet material support.

The nozzle systems 7, 9 can be arranged individually and operated individually. The jet streams 26 are activated in the cyclic operation between the beginning and end of a guided on the sheet guiding cylinder 5 sheet material.

In a further development, the nozzle systems 7, 9 can be arranged combined and operated in combination. In this embodiment, the jet stream 26 of the upstream nozzle system 26 exits first and is immediately interrupted when the end of the sheet material passes the print zone 29. Subsequently, the downstream nozzle system 9 is activated so that the second jet stream 26 from the annular gap nozzles 16 impinges on the sheet material and is switched off when passing from the end of the sheet material.
For example, the cyclic operation of the jet streams 26 of the nozzle systems 7, 9 can be realized in such a way that it overlaps. Here, first the upstream nozzle system 7 is activated and shortly before switching off this nozzle system 7, the downstream nozzle system 9 is already activated.

[REFERENCE LIST]

1

printing unit

2

boom

3

coating unit

4

transfer cylinder

5

Printing cylinder, sheet guiding cylinder

6

conveyor system

7

upstream nozzle system

8th

conveying direction

9

downstream nozzle system

10

plate cylinder

11

Blanket / form cylinder

12

applicator roll

13

dosing

14

drying device

15

traverse

16

annular die

17

distribution channel

18

feed

19

switching valve

20

Compressed air source

21

side frame

22

annular gap

23

gap flow

24

ambient air

25

cone

26

(second) jet flow

27

insert element

28

body

29

pressure zone

30

channel

31

suction

32

thread

Claims (9)

1. A method for sheet guidance in a rotary printing press in the region of a printing zone (29) formed by a rubber blanket/form cylinder (11) and a sheet guiding cylinder (5) by means of air jets which between start and end of a sheet material guided in a sheet guiding cylinder (5) issue from a blowing device (7, 9) arranged parallel to the axis of the sheet guiding cylinder, and the rubber blanket/form cylinder (11) during printing operation is set against the printing zone (29) or, if the rubber blanket/form cylinder (11) is not involved in the printing, there is a gap between said rubber blanket/form cylinder and the sheet guiding cylinder (5), wherein the air jets issue as gap flow (23) with very high speed from a nozzle system (7)supplied with compressed air arranged before of the printing zone (29), that the gap flow (23) drags with it ambient air (24) to a high degree, that the gap flow (23) and the ambient air (24) form a jet flow (26) at least directed against the rubber blanket/form cylinder (11), that the jet flow (26) cyclically only issues in the phase between start and end of the sheet material guided on the sheet guiding cylinder (5) and is immediately interrupted when the end of the sheet material passes the printing gap (29).
2. The method according to Claim 1, characterized in that a second gap flow (23) cyclically issues from a compressed-air supplied nozzle system (9) arranged after the printing zone (29) and the second gap flow (23) and the ambient air (24) form a jet flow (26) directed against the sheet guiding cylinder (5) which between start and end of a sheet material guided in the sheet guiding cylinder (5) hits said sheet material
3. The method according to Claim 1, characterized in that at least the jet flow (26) directed at the rubber blanket/form cylinder (11) issues from the nozzle system (7) before the printing zone (29) in the phase between middle and end of the sheet material.
4. The method according to Claim 2, characterized in that the second jet flow (26) directed against the sheet guiding cylinder (5) issues from the nozzle system (9) after the printing zone (29) in the phase between middle and end of the sheet material.
5. The method according to Claims 1 and 2, characterized in that the cyclical operation of the jet flows (26) of the nozzle systems (7, 9) overlaps.
6. A device for sheet guidance in a rotary printing press in the region of a printing zone (29) formed by a rubber blanket/form cylinder (11) and a sheet guiding cylinder (5) with air jets that issue between start and end of a sheet material conveyed ' on the sheet guiding cylinder (5) from a blowing device (7, 9) arranged parallel to the axis of the sheet guiding cylinder, and the rubber blanket/form cylinder (11) during printing operation is set against the printing zone (29) or with a rubber blanket/form cylinder (11) not involved in the printing there is a gap between said rubber blanket/form cylinder and the sheet guiding cylinder (5), wherein in conveying direction (8) of the sheet material before the printing zone (29) as blowing device a nozzle system (7) formed of a plurality of ring gap nozzles (16) with a ring gap (22) arranged on the outside or on the inside is detachably fastened on a frame-fixed beam (15), that at least a plurality of ring gap nozzles (16) are directed against the rubber blanket/form cylinder (11) and the ring gaps (22) are functionally connected with a distribution channel (17), an upstream supply channel (18) and an upstream controllable switching valve (19) with a compressed-air source (20).
7. The device according to Claim 6, characterized in that in conveying direction (8) of the sheet material after the printing zone (29) as blowing device a downstream nozzle system (9) formed of a plurality of ring gap nozzles (16) with a ring gap (22) arranged on the outside or on the inside is detachably fastened on a frame-fixed beam (15),that each ring gap nozzle is directed at the sheet guiding cylinder (5) and the ring gaps (22) are functionally connected with a distribution channel (17), an upstream supply channel (18) and an upstream controllable switching valve (19) with a compressed-air source (20).
8. The device according to anyone of the Claims 6 or 7, characterized in that the ring gap nozzles (16) on the beams (15) are adjustable in axial and/or in circumferential direction.
9. The device according to at least Claim 6, characterized in that at least one ring gap nozzle (16) of the upstream nozzle system (7) is directed at the sheet guiding cylinder (5).

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