EP0725025B1 - Sheet guiding device for printing machines - Google Patents

Description

The invention relates to a sheet guiding device for Printing machines with guide surfaces for guiding the sheet, being in the guide surfaces nozzles are provided, which with blown air or Suction air can be acted upon.

Such a sheet guide device is from the DE 34 11 029 C2 known. With this sheet guiding device tries to hover the bow safely achieve nozzles in the form of perpendicular in the guide surfaces arranged holes a certain proportion of the area Identify the guiding surface. A disadvantage of this Sheet guiding device is that the nozzles are perpendicular against the bow to be guided. The one from the nozzles escaping air bounces against the bow, must be under it Application forces are redirected and then flows from the nozzle injection point from radially under 360 ° after all Pages from. The impulse forces resulting from the deflection stimulate the bow to flutter. To be unstable through this and turbulent jet clear jets stably lead, it is necessary to apply the impulse force very sensitively adjust the respective substrate. The form of the air blown in must be minimal. However, to nonetheless, the entire sheet guiding area must be greased hold is a high volume flow and to generate this a very specific proportion of the area of nozzle bores in the Management level necessary.

Furthermore, in the device according to DE 34 11 029 Air volume flowing out of the nozzles, after their deflection through the arch, the same air volumes of the neighboring Nozzles directed opposite. These face each other Volumes collide and create around the nozzles Areas with turbulence fields where the jet air swirls and the kinetic energy of the jet air is consumed.

In these zones, due to the strong vortex formation a disruption of sheet transport. The bows become Flutter and excited to vibrate and especially the Trailing edge carries out lashing movements. The Possibility of smear-free a sheet printed on both sides it can only be managed, if at all, at a lower rate Machine speed and takes a considerable amount of time for the adjustment of the inherently unstable Blown air free jets given. A machine anyway to be able to operate, the nozzles with suction air acted upon and only generate one under friction Sheet guide, the higher speeds of the printing press allows. Now a sheet printed on both sides should be processed areas are necessary on the back, which must remain blank. In these areas, the absorbing holes become active. It is in between possible by blowing air on the printed sheets to lubricate prevent, since the sheet holding forces only ever from the sucking Areas are created.

The invention has for its object a To create sheet guide, which has the disadvantages of Avoids state of the art and a safe Sheet run with different substrates in straight printing as well as in perfecting with minimal set-up times ensures.

This object is achieved according to the invention by the features of Claims 1 and 2 solved. Other features of the invention are contained in the subclaims.

The advantage of the invention is that in the preferred operating mode, the blown air mode, the Printing machine capable of through the tangential air flow all printing materials to be processed are safe and to be lubricated-free. This is done through the leadership of the Arch on an air flow caused by the tangential and rectified blowing direction of the nozzles from several individual streams to one main stream with one united flow direction united. This pouring Air cushion is due to its uniformity and Uniformity able to bow without touching the sheet guide plates and thus free of grease, even in the case that both sides of the sheets are freshly printed. This is especially true at all machine speeds possible with shorter set-up times as a time-consuming adjustment of the air flow to the substrate and the speed of the press is very rare becomes necessary. To a machine, which is optionally in the Straight printing or in perfecting is operated in Case of processing of touch-insensitive Back of sheets even at the highest machine speeds as soon as possible, d. H. with minimal setup and Response times, in the state of a safe continued printing move, the invention provides that in straight printing a Conversion of the sheet guide is possible through the problematic areas of the sheet run a suction takes place, the sheet metal touching the unprinted sides of the Bow can result. Such sheet metal contact In this case it does no harm, but can lead to one lead to a significant reduction in machine set-up time. The In this case, sheets become clean and smooth on the sheet led along. You will experience a braking force, the one Tightening causes so that the bow without this any formation of wrinkles and air pockets the next Printing cylinders can be passed.

The areas or sections of the Printing presses are preferably on all sheet-guiding Drums arranged as it is easy in their centrifugal range comes to sheet running disturbances. These drums are for example, the one following the investor Feed drum to the arranged between the printing units Transfer drums and around the delivery drum with which the The delivery takes over the sheets from the last printing unit. If additional Transfer drums are built into the machine, guide surfaces should also be attached there, which are in problematic areas can be supplied with suction air. The arrangement of suction air can also be arranged Areas also in the boom, for example in front of the sheet brake possible.

The outlet areas of the guide surfaces are expedient of the sheet-guiding drums located upstream of the printing cylinders designed to be acted upon by suction air. With these drums can be transfer drums between the Printing cylinders of the individual printing units are arranged. It However, it is also possible that between the printing cylinders several sheet transport drums are arranged. In the Sheet transport drum in front of the first impression cylinder a feed drum that feeds the sheet from the feeder takes over and transported to the printing cylinder. It However, it is also possible that another in this area Transport drum is provided. A clean sheet guide is with the sheet leading upstream of the impression cylinders Drums are particularly important because of the support of the bow on the printing cylinders and thus the quality of the print depends. By the action of suction air in these areas the sheet experiences one when it is transferred to the impression cylinder additional advantageous automatic stabilization that the Bow tightens and thereby a smooth application of the Arch serves on the impression cylinder, which in particular the Adaptation of the printing press to the respective substrate in the In the case of touch-sensitive sheet backs considerably is simplified.

Furthermore, the inlet areas of the guiding surfaces of the bow-leading drums optionally with suction air actable. This is beneficial in the event that it is too machine comes to a standstill, for example due to a Emergency stop or when the machine turns slowly in tip mode. Is such a machine downtime or slowly turn the bow end in the infeed area the guide surface of a sheet-guiding drum, so in the Rule the back end of the bow overhead, and the Machine stop or a very slow forward rotation cause the bow end to fall down and it becomes a Folding of the bow comes. In the state of the art known machines, the printing press must first such sheets eject in tip mode, or they must be removed until a new print is made can. Due to the suction air in the inlet area of the The end of the bow becomes the guide surface of the bow-guiding drums kept safe, and it is possible after a Machine stop or after slowly turning the Printing press to continue printing immediately as there is none Falling down the ends of the bow comes up.

A further development of the invention provides that the Air supply is via axial fans, which are related their direction of rotation are switchable. This allows you to very simple way to switch the desired one Carry out sections of the printing press.

The air supply to the nozzles is preferably via variable speed fans. In this way Blowing operation the hover guide can be set, and in It is possible to suction the paper adapted frictional force of the bow on the guide surfaces adjust. In addition, there is the suction mode Possibility to suck just enough air that it is not yet there is a contact between the bend and the baffle.

It is possible to pass through relatively large nozzles individually To supply fans with the desired air, or an air supply can be provided at which individual areas or parts of the air supply via Air supply box is done. There is at least one Subdivision of the guiding surfaces into areas required either blowing or suction air can be applied and those areas of the guide surfaces, which are preferably only in Blown air operation can be operated. It goes without saying further subdivision possible, according to how strong the Air exposure in a specific area Guide surface has to take place. The advantage of air supply boxes is that many nozzles by means of a Air supply element can be supplied. So for a larger number of nozzles, for example strong axial fans are used. Through the It is still possible to subdivide the individual areas to apply air to the guide surfaces variably. Therefore it is proposed that each blow box have an axial fan assign and the size of the air supply boxes to the Adjust air requirements in the respective areas.

A further development provides that the control surfaces a different, adapted to the respective air requirement Have area coverage with nozzles. For example possible to use the inlet and outlet areas of the guide surfaces a higher area occupancy and those in between Leadership zones with a lower area allocation too Mistake. It is also possible to cover the area with nozzles largest in the middle of the sheet path and to the edge declining. This is particularly useful if the nozzles towards the outside of the sheet path are directed slot nozzles. It will then be in the middle of the Arc run generates the appropriate airflow that to Edge only needs to be maintained, so no more the number of nozzles is required, as in the middle of the Sheet raceway.

All sections that can be exposed to air are advantageous the press with a remote control. In particular, the switch to suction operation by a Remote control is time saving when the machine is off Backprint on straight printing or on the operation with problematic papers to be converted. Very easy can do this by electronic control of the Axial fans or other fans take place.

The invention is described below with reference to the drawing illustrated embodiments explained.

Fig. 1

eine schematische Darstellung der Druckmaschine mit der erfindungsgemäßen Bogenleiteinrichtung,

Fig. 2

eine vergrößerte Darstellung einer Leitfläche der Umführtrommel,

Fig. 3

eine aus Luftversorgungskästen aufgebaute Bogenleiteinrichtung,

Fig. 4, 5, 6

Axialventilatoranordnungen bei Luftversorgungskästen,

Fig. 7

eine Düsenanordnung,

Fig. 8

eine Schlitzdüse und

Fig. 9

zeigt eine Leitfläche bei der das Ansaugen des Bogens in mittig zur Bogenlängsachse angeordneten Abschnitten erfolgt.

Show it:

Fig. 1

2 shows a schematic representation of the printing press with the sheet guiding device according to the invention,

Fig. 2

an enlarged view of a guide surface of the transfer drum,

Fig. 3

a sheet guiding device constructed from air supply boxes,

4, 5, 6

Axial fan arrangements in air supply boxes,

Fig. 7

a nozzle arrangement,

Fig. 8

a slot nozzle and

Fig. 9

shows a guide surface in which the suction of the sheet takes place in sections arranged centrally to the longitudinal axis of the sheet.

Fig. 1 shows a schematic representation of a Printing machine with an embodiment of an inventive Sheet guiding device. In the printing press are for simple representation of only two printing units 20 and 20 ' shown; usually has such a printing press however over four and more printing units. Each printing unit 20, 20 ' has a pressure cylinder 8, 8 ', Rubber cylinder 9, 9 'and a plate cylinder 10, 10' and about ink works not shown. Between the printing units 20 and 20 'provides a transfer drum 6 for forwarding the sheet to be printed 4. Has a printing press multiple printing units, so there are always between two printing units Transfer drums 6 arranged. Of course it is possible that 6 instead of a transfer drum Sheet transport drums are arranged. In the illustrated Printing machine, the sheet track 17 is shown, wherein arrows 24 show the direction of sheet travel. The arch 4 are removed from a feeder stack 19 and by means of a feeder, not shown, to a feed drum 5 passed on the sheet 4 with their grippers one Printing cylinder 8 passes for printing. From the impression cylinder 8 the sheet 4 is gripped by the gripper 26 of the transfer drum 6 taken over and fed to a further pressure cylinder 8 ', so that further printing can take place. In the machine shown passes the pressure cylinder 8 to Sheet 4 to the delivery drum 7 of a boom 21. Die Delivery drum 7 is the transfer drum for gripper bridges, which are arranged on the boom chain 22 and which the sheet 4 taken over to the end of the jib 21 transport where the sheets 4 on the delivery stack 23rd be filed.

In section 3 of the printing press there is an additional one Sheet guide useful, so that the sheet 4 clean transported and especially the printing cylinders 8 and 8 'smooth to be handed over. Sections 3 include this Baffles 1 arranged, preferably a number of have slot-shaped nozzles 2. These are in the 1 not shown, but they are to take the example of the transfer drum 6 of FIG. 2. The Nozzles 2 are constructed in such a way that at least some of the nozzles 2 their blowing air essentially tangent to the surface of the Guide surface 1 in the between the arch 4 and the guide surface 1st supplies formed area. The angle between airflow and Surface can be between 0.1 ° and 30 °, for example be. The arrangement of the nozzles 2 and the blowing direction the same is further preferably chosen so that the Air flows from adjacent nozzle groups to one Total flow with essentially parallel streamlines overlay. The guide surface 1 on the transfer drum 6 shows a total of four separated by partitions 44, 46, 48 Nozzle areas 11, 12, 40, 42, which by a Axial fan 15 are charged with air. The Nozzle areas 11, 12, 40, 42 consist of several nozzles 2, seen in the direction of Fig. 2 one behind the other are arranged. The arrows 25 show the possible Blowing direction of the axial fans 15. A sheet 4, which from the pressure cylinder 8 by means of a gripper row 26 was taken over by the transfer drum 6, the Printing cylinder 8 'transported further.

If the sheet guiding device works in the blowing mode, the bow 4 experiences a levitation in which it between the transfer drum 6 and the guide surface 1 without touching the guide surface 1 is guided. Such a levitation is for example in reverse printing, since none of the Sides of the sheet 4 on the transfer drum 6 or on the Lubricate guide surfaces 1.

However, if the machine is run in face-to-face printing, then it is lower side of sheet 4 unprinted, and a floating guide not necessary. So it can be critical Sections 3 of the printing press guide the sheet 4 can be chosen along the guide surfaces 1, thereby the to shorten the set-up times mentioned at the beginning. To for this purpose, the axial fans 15 in Inlet area 11 and one in the outlet area 12 corresponding guide surface 1 switched to suction mode. As a result, the arch 4 can be moved along the areas 11 and 12 of the guide surfaces 1 slide, between sheet 4 and the Baffles 1 frictional forces can occur. The bow 4 is thereby held in the inlet area 11, so that it at slow machine operation or when the machine stops with its rear end not falling down and it as a result, the sheet 4 cannot be folded. Farther the suction operation in the outlet area 12 leads to a tightening of sheet 4, making labile papers, especially those with low basis weight, e.g. Bible papers, also at transfer maximum speed to the pressure cylinder 8 and therefore neither waves nor air pockets exhibit. This way, even problematic papers with high quality and greatest speed under Compliance with minimum machine set-up times can be printed. A guide of the arch 4 along the guide surfaces 1 in Outlet area 12 can also be used for less problematic Papers can be helpful when using the printing press For example, it runs accordingly fast and therefore high Centrifugal forces act on the bow 4, this this to the outside drive, which can cause the sheet 4 to flutter. Also in this case, the guide described by Holding forces generated in both blowing and suction operation on the sheet 4 along the guide surfaces 1 serve that the sheet 4 is neatly applied to the impression cylinder 8 '.

1 shows that also on the feed drum 5 Axial fans 15 are arranged, which in Inlet area 11 or in the outlet area 13 of the corresponding guide surface 1, the nozzles 2 by suction air can apply to a tight arch guidance there too to allow the sheet 4 on the impression cylinder 8 well lies on. There is also a display drum 7 Axial fan 15 is provided, which ensures that a The bow end is guided safely in this area and at one Machine stop cannot fall down, causing it to become a The sheet 4 can fold over and become unusable. It can be seen as in section 3 of the boom 21 more Axial fans 15 can be arranged for sheet guidance, which are used to safely secure the sheet 4 to the delivery stack 23 transport or to the fact that they are above the delivery stack 23 are acted upon with blowing air in such a way that they become place it quickly on delivery pile 23.

3 shows a guide surface 1 which has nozzles 2 which by means of air supply boxes 16 and 16 'with air be charged. The top view of the Guide surface 1, the partitions shown as lines are and for the division into different air supply boxes 16 and 16 'care. The areal density of the as Slit nozzles 18 formed nozzles 2 is preferred trained differently. So are in the inlet area 11th two air supply boxes 16 arranged, which are high Have surface density at nozzles 2. Then comes one Guide zone 14 with a surface density of nozzles 2, which in middle area is stronger and weaker at the edges. This guide zone 14 corresponds e.g. the Nozzle areas 40, 42, in which a blowing air is applied is sufficient for every operation of the printing press. Of the Guide zone 14 closes in the direction of sheet travel 24 the outlet area 12, which has a higher nozzle density has, and in the relatively large suction air operation Holding forces must act on the arch 4.

Fig. 4 shows how that shown in Fig. 3 Air supply boxes 16 and 16 'axial fans 15 can be assigned. However, it is also possible that Arrangement of air supply boxes 16, 16 'and Axial fans 15, as shown in Fig. 5 to make. This arrangement essentially corresponds to that in FIG. 2 shown arrangement of air supply boxes with Partitions 44, 46, 48.

Fig. 6 shows how with less air requirement on a Subdivision can be dispensed with, so that in the inlet area 11 and in the discharge area 12 each a blow box 16 and in a large blow box 16 '' 'is arranged in the guide zone 14 is. The nozzle arrangement, which is is shown in Fig. 7.

8 shows the preferred embodiment of the nozzles 2, which has already been indicated in Fig. 3. It is a matter of Slot nozzles 18, which in the sheet metal of the guide surfaces 1 are easy to punch. The one shown in Fig. 3 The blowing direction is directed outwards (Arrows 50), causing a tightening of the arch 4 across its direction of travel is achieved. For this purpose it is required that two strong outwards in the middle directed air currents are formed, which are to the side of the Move bow 4, and the outside with a smaller Number of nozzles 2, 18 can be maintained.

In a preferred embodiment of FIG Invention are in the inlet area 11 and / or Outflow area 12 of the guide surface 1, nozzle areas 52, 54 provided, the nozzles depending on the to be processed Printing material can be switched between blowing and suction operation.

The remaining nozzles of the guide surface 1 are in this Embodiment of the invention preferably in the blowing mode operated. The nozzle areas 52, 54 preferably have each have a fan 15 assigned to them preferably arranged centrally to the sheet raceway 17 and have a width less than the smallest of sheet format that can be processed by the printing press.

The exemplary embodiments merely represent possibilities of Design of the sheet guide device according to the invention, further embodiments with different nozzle arrangements, possibly other blowing directions are also possible. Instead of the Axial fans 15 can also provide a central air supply with blowing and suction air or another type of fan be used.

REFERENCE SIGN LIST

1

Control surfaces

2nd

Nozzles

3rd

Areas with additional arch guidance

4th

bow

Bow-leading drums:

5

Feed drum

6

Transfer drum

7

Delivery drum

8, 8 '

Impression cylinder

9, 9 '

Rubber cylinder

10, 10 '

Plate cylinder

11

Infeed areas of the sheet leading drums

12th

Outfeed area of the transfer drum

13

Outfeed area of the feed drum

14

Leadership zones

15

Axial fans

16, 16 ', 16' ', 16' ''

Air supply boxes

17th

Sheet raceway

18th

Slot nozzles

19th

Stack of feeders

20, 20 '

Printing units

21

boom

22

Cantilever chain

23

Delivery pile

24th

Arrows that show the direction of sheet travel

25th

Arrows that indicate the direction of the blow Symbolize axial fans

40

Nozzle area

42

Nozzle area

44, 46, 48

Partitions

50

Blowing direction

52, 54

Sections

Claims (13)

1. Sheet guiding device for printing machines with guide surfaces (1) for guiding the sheets (4), nozzles (2, 18) to which blown air or suction air can be applied being provided in the guide surfaces (1), characterized in that, viewed in the sheet transport direction (24), nozzles (2, 18) arranged in the entry region (11) of a guide surface (1) can have suction air or blown air applied to them optionally, depending on the printed material being processed, and in that the nozzles (2, 18) of the guide zone (14) arranged between the entry region (11) and the exit region (12) of the guide surface (1) have blown air applied to them, at least some of the nozzles (2, 18) feeding the blown air essentially tangentially to the surface of the guide surface (1).
2. Sheet guiding device for printing machines with guide surfaces (1) for guiding the sheets (4), in particular according to Claim 1, nozzles (2, 18) to which blown air or suction air can be applied being provided in the guide surfaces (1), characterized in that at least some of the nozzles (2, 18) arranged in the exit region (12) of a guide surface (1), viewed in the sheet transport direction, can have suction air or blown air applied to them optionally, depending on the printed material being processed, and in that the nozzles (2, 18) of the guide zone (14) arranged between the entry region (11) and the exit region (12) of the guide surface (1) have blown air applied to them, at least some of the nozzles (2, 18) feeding the blown air essentially tangentially to the surface of the guide surface (1).
3. Device according to Claim 1 or 2, characterized in that the air supply to the nozzles (2, 18) is carried out via speed-controllable fans.
4. Device according to one of Claims 1 to 3, characterized in that the air supply to the nozzles (2, 18) is carried out via axial fans (15) which can be switched over with reference to their direction of rotation.
5. Device according to one of Claims 2 to 4, characterized in that the air supply of individual sections (3) of the printing machine or of parts of the same is carried out by air supply boxes (16, 16', 16'', 16'''), a fan (15) being assigned to each air supply box (16, 16', 16'', 16'''), and the size of the air supply box (16, 16', 16'', 16''') being matched to the air requirement of the respective section (3).
6. Device according to one of the preceding claims, characterized in that the guide surface (1) has a different area population of nozzles (2, 18) that is matched to the respective air requirement.
7. Device according to Claim 6, characterized in that the area population of nozzles (2, 18) is greatest in the centre of the sheet running path (17) and decreases towards the edge of the sheet running path (17).
8. Device according to one of the preceding claims, characterized in that the nozzles (2, 18) are slot nozzles (18) directed in the direction towards the outside of the sheet running path (17).
9. Device according to one of the preceding claims, characterized in that the changeover between suction operation and blowing operation is carried out by remote control.
10. Device according to one of the preceding claims, characterized in that the nozzles (2, 18) at the entry region (11) of the guide surface (1) have suction air applied to them when processing lightweight printed materials.
11. Device according to one of Claims 2 to 10, characterized in that the nozzles (2, 18) at the exit region (12) of the guide surface (1) have suction air applied to them when processing lightweight printed materials.
12. Device according to one of the preceding claims, characterized in that suction by means of the suction air is carried out in a section (52, 54) of the guide surface (1) which is essentially arranged centrally in relation to the sheet running path (17) in the entry region (11) and/or exit region (12) of the guide surface (1).
13. Device according to Claim 12, characterized in that the width of the section (52, 54) is smaller than the width of the smallest sheet format that can be processed by the printing machine.

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