GB2316913A

GB2316913A - Device for the treatment of sheet-like printed materials

Info

Publication number: GB2316913A
Application number: GB9719287A
Authority: GB
Inventors: Manfred Herold; Ulrich Jung
Original assignee: MAN Roland Druckmaschinen AG
Current assignee: Manroland AG
Priority date: 1996-09-10
Filing date: 1997-09-10
Publication date: 1998-03-11
Anticipated expiration: 2017-09-10
Also published as: DE19636658C2; JP2935680B2; JPH1086332A; GB2316913B; FR2753129A1; DE19636658A1; GB9719287D0; FR2753129B1

Abstract

The invention relates to a device for treatment of sheet-like printed materials (4), particularly for heat drying or powder application, in a printing press. Improved results are obtained by the use of rows of nozzles (11, 12, 13) of length adjustable to match the sheet format, which rows are rotated about an axis (16) so that they dip into spaces between successive gripper systems (2) to be closely adjacent the sheet-like material (4), at which position a suitable medium (hot air for drying, powder and air for powdering) is ejected from the outlet openings of the nozzles towards the sheets (4).

Description

2316913 DEVICE FOR THE TREATMENT OF SHEET-LIKE PRINTED MATERIALS This

invention relates to a device for the treatment of sheet-like printed materials in printing presses, particularly surface treatment by means of heat drying or powder application.

A device for surface treatment of printed materials by heat drying is known from DE 44 42 942 Al. A blowing bar with a plurality of blowing channels incorporates a heating device as a heating cartridge in a housing.

A device for surface treatment by powder application is known from DE 295 17 283 Ul. In the delivery of a printing press, a powder shower is arranged with a series of powder nozzles extending across the format width. Fitted to the powder nozzles is a blower directed towards the sheets, wherein the powder nozzles themselves are arranged in the airstream generated by the blower. In a further development, between blower and powder nozzles, an air guiding element is arranged to generate a laminar air flow.

Disadvantageous with these constructions is that particularly by the circulating gripper systems, airstreams necessarily arise which, depending upon the type of surface treatment, agitate the hot air or the powder on the printed material surface. Thereby satisfactory drying or powder application results are obtained mainly only in the region of the sheet front edge guided in the gripper closure. Insufficiently dried or powdered printing materials can stick to one another on pile formation or form the pile skewed, which is to be traced back to an excess powdering of the rear region of the printed material. Contamination of the delivery as well as of the gripper system is furthermore the result and overall unnecessarily much energy and powder is used up. In this connection, it is furthermore disadvantageous that the powder nozzles or hot air nozzles themselves generate turbulent airstreams which act negatively on the sheet guidance.

It is the object of the invention to create a device, the surface treatment of sheet form printed materials by means of heat drying or powder application of which is influenced by airstreams as little as possible.

In accordance with the invention, there is provided apparatus for the treatment of sheet-like printed materials, particularly for heat drying or for powder application in printing presses, wherein the sheet-like printed materials are moved along a path by way of a feeder system set in a frame and having gripper systems circulating about the path and guiding the printed material in a gripper closure, the apparatus including at least one row of outlet nozzles extending across the maximum format width and arranged rotatably about an axis mounted horizontally with respect to the frame and with respect to the path of the gripper system; means for swivelling the outlet nozzles after passage of a gripper system into the path of the gripper system and out of this path before passage of a following gripper system, and means for subjecting the outlet nozzles to at least one medium while they are located in a defined sector of their rotation and directed towards the path of the sheet material.

In accordance with the invention, the device has rotatable outlet nozzles which, in the rhythm of the machine, apply the respective medium (hot air or powder) on to the printed material for surface treatment. By rotatable outlet nozzles, the distance to the printed material is reduced so that in the case of heat drying, the drying power is used up better and in the case of powder application, the powder is arranged distributed more evenly on the printed material. The region of the printed material located directly behind the gripper system is dried or powdered respectively better since the rotating outlet nozzles extend to a distance closer to the printed material and on the passage of the gripper systems rotate around these. The core stream of each outlet nozzle is utilised better. The circulating feeding system always runs in the free spaces of the rotating outlet nozzles. Furthermore, improved sheet guidance is obtainable since the airstreams are less turbulent. By means of the more even drying, the print quality is improved and by the more even powder application, pile formation improved.

The invention is illustrated by way of example with reference to the accompanying drawings, in which:

Figure 1 shows a delivery of a printing press in diagrammatical side view; Figure 2 is a diagrammatic side view of a first device for surface treatment in accordance with the present invention, and Figure 3 is a like view of a second device for surface treatment in accordance with the invention.

Referring first to Figure 1, this shows a delivery arranged at the end of a multi-colour offset printing press with a varnishing unit. By means of a circulating conveyor system 1, sheets 4 grasped by their front edge in a gripper closure are fed by gripper systems 2 in the sheet running direction 3 past a sheet brake 5 to a delivery pile 6 and laid against stops. For accelerating sheet deposition on to the delivery pile 6, a blowing unit 14 is arranged in an area above this. The delivery furthermore has sheet guide devices 7, 8 wherein the sheet guide device 7 is preferably double walled and, for cooling sheets 4 as they pass, has means enabling a flow of a cooling agent to occur through the device. Above the sheet path are located a drying device 10 and a powder application device 9. Drying.device 10 and powder application device 9 are essentially constructed identically and their construction is shown in more detail in Figure 2 which shows the powder unit 9.

The powder unit 9 extends across the maximum format width of the printed material to be worked with and has, according to Figure 2, three rows of outlet nozzles 11 to 13 extending across the width of the printed material and which can be activated in dependence on the format. The three rows are fixed to a central member and evenly spaced offset by 120 around the periphery. The outlet nozzles 11 to 13 are preferably arranged flush in each row and are rotatable in the direction of rotation 15 (in the mathematically negative rotational sense) so that the row of nozzles nearest the path of sheets 4 moves in the same direction as the sheet running direction 3. The rows of nozzles rotate about a central axis 16 transverse to the sheet running direction 3 and horizontal with respect to the frame. The openings of the outlet nozzles 11 to 13 are constructed, e.g., as slots. The ends of each row of the outlet nozzles 11 to 13 are preferably coupled with a rotary transformer 17 which is arranged to feed the appropriate medium, e. g. powder in combination with compressed air for the surface treatment only while the row of nozzles lies within a defined sector bounded by radii 18. Thus, as the rows rotate, medium is fed in turn to each row of outlet nozzles 11, 12 and 13. If desired, the powder and also compressed air can be fed separately to the outlet nozzles 11 to 13 and can emerge from separate but neighbouring openings in those nozzles, so-called twin beam nozzles. The compressed air emerging entrains the preferably intermittently emerging powder particles from the neighbouring openings in the flow direction and both media mix up.

Figure 3 shows an alternative powder device or drier device with only two rows of outlet nozzles arranged offset around the periphery by 180'. The outlet nozzles 11, 12 are again arranged flush in a row across the maximum format width and mounted rotatably about the axis 6 16.

The device shown in Figure 2 is essentially constructionally identical when used as a drier device 10, though when so used, the rows of nozzles are sequentially coupled via the rotary transformer 17 with an external supply of compressed air, preferably a hot air supply, as they rotate. Via the outlet nozzles 11 to 13, in dependence on format, the printed material is subjected to hot air.

The outlet nozzles 11 and 13, shown turned away from the sheet 4 in Figure 2 are, in that position and whether the device is being used as a powder device 9 or as a drying is device 10 ineffective, as the construction of the rotary transformer 17 ensures the feed of the respective medium to the nozzles only when they lie within a defined sector bounded by radii 18.

The mode of operation is as follows:

The circulating conveyor system 1 transports, by means of gripper system 2, printed and varnished sheets 4 in the sheet running direction 3 to the delivery pile 6. The first device for surface treatment which sheets 4 pass is arranged as drier device 10. The outlet nozzles 11 to 13 rotate in the rhythm of the press so that always a row of nozzles 11 or 12 or 13 is coordinated to a sheet 4. The gripper system 2 goes past the drying device 10 in the sheet running direction 3. In this connection, the nozzles 11 to 13 are located in a position in such a fashion that no collision can take place with the gripper system 2.

The heat drying is explained in more detail with reference to the example of the series of outlet nozzles 13. After the passage of the gripper system 2, the row of rotatable outlet nozzles 13 swivels into the region of the circulating conveyor system 1 and the outlet nozzles 13 are subjected, via the rotary transformer 17 and over a defined sector bounded by radii 18, to hot air. In this connection, the series of outlet nozzles 13 can rotate into the position where the nozzles are close to sheet 4 and then remain stationary in a defined position while sheet 4 travels past, or slowly further swivel in the direction of rotation 15. Continuous or intermittent drive mechanisms, coordinated to the press rhythm, may be used to effect the desired movement of successive rows of nozzles. The outlet nozzles 13 are arranged to be adjacent the sheet path and fed with appropriate medium for a length of time dependent on the format of the sheet 4 being transported. Once the sheet 4 leaves the region of drying device 10, then the outlet nozzles 13 are swivelled out of the path of the gripper system 2 in the direction of rotation 15. The hot air feed is switched off. Thereby, a free space for the passage of the following gripper system 2 is created. Immediately after passage of the following gripper system 2, the next row of outlet nozzles, i.e. after row 13, row 12 swivels into the path of the circulating gripper systems 2. The outlet nozzles 12 are coordinated in dependence on format to the next sheet 4, and the hot air feed is activated. When the second sheet 4 leaves the region of the drier device 10, the outlet nozzles 12 swivel out of the path of the gripper system 2 again so that after passage of the next gripper system 2 with the third sheet 4, the outlet nozzles 11 swivel in and can be activated dependent on format and coordinated to the sheet 4.

This working principle is maintained up until the end of printing, with the gripper systems 2 running in and out of the f ree spaces between the sets of rotating outlet nozzles 11 to 13, as they move in the sheet running direction 3.

Once past the drier device 10, the sheets 4 are fed further in the sheet running direction 3 to pass the subsequently arranged powder application device 9. The powder application device 9 is essentially constructionally identical to drier device 10, it has again three rows of outlet nozzles 11 to 13 arranged offset around the periphery by 120 or also to 11 to 12 respectively offset by 18C, which swivel rotatably about the axis 16 in the direction of rotation 15. The outlet nozzles 11 to 13 are linked with an external powder supply system for powder in combination with compressed air and are driven analogously to drier device 10 over a defined sector bounded by radii 18. With separated powder or compressed air supply (twin beam nozzles), the media supply also separated in the rotary transformer 17 is supplied over a defined circular sector and transported with separate conduits to the outlet nozzles 11 to 13.

The rotary transformer 17 is constructed of a stationary portion and a rotating portion. The stationary portion is provided with a stationary transformer face, that face having an aperture therein angularly midway between the radii 18. The aperture communicates with a supply chamber which is connected to feed means for whatever material is to be passed through nozzles 11 to 13.

The rotary portion is provided with a rotary transformer face, that face having as many apertures therein as there are rows of outlet nozzles. The apertures are positioned so that they communicate with the ends of the conduits that supply nozzles 11 to 13. 5 In use, the stationary and rotating transformer faces are adjacent to each other and so positioned that when the rotary face rotates the apertures therein sequentially overly the aperture in the stationary face. Pressurised air and/or powder is supplied to the supply chamber and when each aperture in the rotating face overlies the aperture in the stationary transformer face, the pressurised air and/or powder passes into the conduit supplying a row of nozzles.

is The stationary and rotating transfer faces are most preferably sealed to each other to prevent the pressurised air and/or powder from exiting the supply chamber except into a conduit. It is preferred that the apertures in both transformer faces are of the same shape, and most preferentially, they are both trapezoidal.

Because of the dipping rotational movements of the powder applicator device 9 and drying device 10 in combination with the gripper systems 2, circulating in the rhythm of the press, the outlet nozzles 11 to 13 can be brought close to the respective sheets 4. Thereby, the distances between sheet 4 and outlet openings 11 to 13 are small, which noticeably improves the results of the drying and/or powdering process. As a result, the sheets 4 dry more evenly across the format and the powder is itself distributed more evenly in the region of the sheet front edge.

Claims

1. Apparatus for treating sheet-like printed materials, particularly for heat drying or for powder application in printing presses, wherein the sheet-like printed materials are moved along a path by way of a feeder system set in a frame and having gripper systems circulating about the path and guiding the printed material in a gripper closure, the apparatus including at least one row of outlet nozzles extending across the maximum format width and arranged rotatably about an axis mounted horizontally with respect to the frame and with respect to the path of the gripper system; means for swivelling the outlet nozzles after passage of a gripper system into the path of the gripper system and out of this path before passage of a following gripper system, and means for subjecting the outlet nozzles to at least one medium while they are located in a defined sector of their rotation and directed towards the path of the sheet material.

2. Apparatus according to Claim 1 wherein the means for subjecting the nozzles to a medium are adapted to supply compressed air thereto.

3. Apparatus according to Claim 1 wherein the means for subjecting the nozzles to a medium are adapted to supply a powder in combination with compressed air thereto.

4. Apparatus according to any one of Claims 1 to 3 and including means to swivel the outlet nozzles into and out of the path of the gripper systems in the rhythm of the press.

5. Apparatus according to any one of Claims 1 to 4 and wherein the outlet nozzles are arranged to rotate in a direction of rotation such that the nozzles nearest the sheet path run substantially in the same direction as the sheet running direction.

6. Apparatus according to any one of Claims 1 to 5 and including means to actuate or close off one or more of the outlet nozzles dependent upon the sheet format to be treated.

7. Apparatus according to any one of Claims 1 to 6 and including a rotary transformer adapted to connect an external supply unit for the corresponding treatment medium with t-he row(s) of outlet nozzles.

8. Apparatus according to Claim 7 wherein the rotary transformer is adapted to connect the supply unit to the outlet nozzles only over a defined circular sector of the rotary path of the nozzles.

9. Apparatus according to any one of Claims 1 to 8 and including a plurality of rows of outlet nozzles arranged equi-angularly spaced about a common axis of rotation.

10. Apparatus according to Claim 9 and including two rows of outlet nozzles offset by 180 about the axis.

11. Apparatus according to Claim 9-and including three rows of outlet nozzles offset by 120 about the axis.

12. Apparatus according to any one of Claims 1 to 11 wherein the outlet nozzles have slit-shaped openings.

13. Apparatus for the treatment of sheet form printed materials within a printing press substantially as hereinbefore described with reference to the accompanying drawings.