GB2263437A

GB2263437A - Web handling between printing press and dryer.

Info

Publication number: GB2263437A
Application number: GB9301013A
Authority: GB
Inventors: Ralf Haller
Original assignee: Heidelberger Druckmaschinen AG
Current assignee: Heidelberger Druckmaschinen AG
Priority date: 1992-01-21
Filing date: 1993-01-20
Publication date: 1993-07-28
Anticipated expiration: 2013-01-20
Also published as: GB9301013D0; DE4201481A1; GB2263437B

Description

2263437 - 1 Device for handling material webs in rotary printing presses

The invention relates to a device for handling material webs in rotary printing presses.

The German patent application DE 39 29 227 discloses a paper web cutting device and a paper web holding device for a web-fed rotary printing press. The paper web holding device consists of two clamping bodies being made of resilient, deformable material. The one of the clamping bodies is displaceable with respect to the other one. The engaging force is created by actuator cylinders. In this disclosure the problem is solved by installing a paper web holding device for each printing unit and a control device after each printing unit.

The German Patent DE 33 09 558 discloses a catching device for printed material webs, which is arranged after the last printing unit and in front of a thermal dryer. This catching device consists of two cylinders which are driven and provided with a layer. The cylinders are of the same dimension as the printing unit cylinders of the preceding printing units. However., since the upper one of the two cylinders of the catching device for a printed material web is designed so as to be displaceable vertically, the drive mechanism automatically tends to be elaborate and costly.

In view of this state of the art, it is the object of the present invention to optimize a device for handling material webs to the extent that, in the event of a web break, the gripped front edge of the material web is directly drawn into an adjacent dryer, in order to enable a quick restart of the machine.

As a solution to the object according to the invention there are arranged, after the last printing unit. a roller with a separate drive and pressdown elements. so that in case of need a material web can be cought as well as drawn into a dryer.

The advantage of this solution is to be seen in the that, in the event of a web break, the remaining part of the web still present in preceding printing units can be wound up behind the last printing unit, be cut, and the new front edge of the material web be threaded into the subsequently arranged dryer. No additional devices are necessary for this process. After the wound-up part of the web has been removed, the machine can be started again und continue in the "production printing" mode. Thus, long stand-sti 11 times do not occur.

In a further development of the inventive idea, a control unit c6ntrols a drive for the roller and an adjustment device for the press-down elements. The control unit is activated by signals and sensors. The signals transmitted by the sensors of the control unit effect an activation of the adjustment device and thereby of the press-down elements for gripping the material web. The press-down elements are pressed against the driven roller. Thereby, the material web remains in a defined position and can subsequently be wound up.

It is another advantageous feature of the invention that, by means of a selector switch, the control unit can be switched between a "production printing" mode and a "thread-in" mode. Thereby is achieved that, while the machine is in the "production printing" mode, the sensors remain activated enabling the detection of a web break, and that, in the event of a web break., the control unit can immediately be switched to the "thread-in" mode. Thus, one and the same control unit 3 - can be used; however, different detection sensors are activated.

In a further embodiment of the invention the control unit, in the "threadin" mode, is activated through signals of sensors which are situated behind the dryer. In this way., the thread-in operations are activated, until the material web emerging from the dryer is registered behind the dryer In the "production printing" mode however the contro i S 0 sensors 1 unit activated through signals of which are situated in front of and behind the dryer, in order to enable an immediate reaction to a web break.

In another press-down device are unit can according space.

embodiment of the invention the roller, the elements, the drive as well as the adjust'ment combined in one material web handling unit. This be installed very near the dryer entrance and to individual requirements and availability of According to yet another embodiment of the invention. the dryer is provided with a pneumatic draw-in device. In the "thread-in" mode this pneumatic draw-in device is automatically activated through the selector switch, when a material web is threaded into the dryer.

According to an alternative embodiment of the invention, the roller, the press-down elements as well as the adjustment device are arranged at the dryer entrance.

The present invention will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Fig. 1 is a view of the inventive device for handling a material web, located at the entrance of a dryer; and Fig. 2 is a view of the inventive device for handling a material web, with all its components located within a closed material web handling unit.

Fig. 1 shows a material web handling device located at the entrance of a dryer. In a printing unit 1 of a rotary printing press there are arranged printing unit cylinders 2 to print on both sides of a material web 6. The printed material web 6 emerging from the printing unit 1 is dried in a dryer 5, and from there, after having passed a group of chill rolls (7), it is transported into a further processing unit (not shown).

A rotational speed measuring means 3, which is located at the printing unit 1, transmits pulses to a control unit 4. The control unit 4 controls the rotational speed of a drive 10, which drives a roller 8, on the basis of the pulses transmitted from said rotational speed measuring means 3. Above the driven roller 8 there are disposed press-down elements 9 which are operated by an adjustment device 11. The adjustment device 11 interacts with a lever 12 which is turnably mounted at the dryer 5 and, at its free end, bears press-down elements 9. The press-down elements 9 can be designed, for example, as individual pulleys being rotatably mounted next to one another or as one single roller extending across the width of the material web 6. The driven roller 8 is attached to the housing of the dryer 5 by means of a roller bearing 13. Within the dryer 5 there is accommodated a pneumatic draw-in device Sa. Through this draw- in device 5a the material web 6 can be transported through the dryer 5, until a sensor 14b transmits a signal to-the control unit 4 indicating the presence of a material web at the end of the dryer.

tl In the event-of a break of the material web 6, a respective signal is transmitted to the control unit 4 through a sensor 14a which herein is arranged below the material web 6. The control unit 4 activates the adjustment device 11, and the press-down elements 9 are pressed onto the roller 8. Thus, the material web 6 is gripped on both sides and can be wound onto the roller 8. This becomes necessary, for example, when the printing on the material web 6 passing between the respective printing unit cylinders 2 in the printing units has become incomplete or deficient, due to sudden trouble-related braking of the machine. Consequently, this deficient part of printed web has to be removed and for that purpose is wound up on the roller 8 then serving as a winding roller, and is cut off. The newly created front end of the material web 6 is gripped between press-down elements 9 and the driven roller 8 and then guided through the dryer 5 by means of the pneumatic draw-in device Sa, until the sensor 14b generates a signal that the material web 6 is present and available at the end of the dryer. This combined web-catching/thread-in device makes the transport of material web 6 considerably easier and reduces the change-over times required for the machine to be brought into a state of resuming production printing to a minimum.

a Fig. 2 illustrates a modification of the material web handling device. In difference to Fig. 1, the device of Fig. 2 shows the components, such as roller 8., press-down elements 9, adjustment device 11 and drive 10 all being accommodated in one closed web handling unit 16. In the operational mode "production printing" the control unit 4, by means of the selector switch 4a, is switched to a state in which the sensor 15a transmits a signal to the control unit 4 immediately upon a web break. Then, the control unit 4 moves the adjustment device 11. The press-down elements 9 are brought into engagement with the roller 8 and thereby the material web 6 is gripped. In this mode of operation - the 6 - press is now stopped the deficiently printed-part of the web still present in the preceding Printing units can be wound up and subsequentLy be removed. The winding-up of said deficiently printed material web 6 is effected through a selection made by means of a selector switch 4a. Besides, fresh printing ink on the material web 6 has a favorable influence on the winding-up process. After the wound-up part of the material web 6 is cut off and removed, the threading-in of the material web 6 into the dryer 5 can take place. As shown in Fig. 1, the dryer 5 is equipped with a pneumatic draw-in device 5a which moves the material web 6 through the dryer. A sensor 15b detects the completion of the thread-in operations into the dryer 5 and feeds this information back to the control unit 4.

The device according to the invention, thus, permits the catching of a material web 6 in the event of a web break and the immediate guiding of the material web 6 into the dryer 5, after a deficiently printed part thereof has been removed from the machine. Thereby, the stand-still times of a press can be considerably reduced and production can be resumed much faster.

It will of course be understood that the present invention has been described above purely by way of example, and modifications of detail can be made within the scope of the invention.

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Claims

CLAIMS:

1. Device f or handling a material web coming from a rotary p:inting machine, comprising a separately driven roller, which is driven approximately at machine speed so as to prevent damage to printing units in the rotary printing machine, and at least one press-down element, both of which are arranged downstream of a last printing unit in the machine in order to catch the material web, if needed, as well as to thread it into a dryer.

2. Device according to claim 1 in which a drive for the roller and an adjustment device for the press-down element are controlled through a control unit.

3. Device according to claim 2 in which the control unit is activated by sensors.

4. Device according to claim 2 or 3 in which the mode of operation of the control unit can be selected by means of a selector switch between the mode "thread-in" and the mode "production printing".

5. Device according to claims 3 and 4 in which the control unit, in the mode of operation "production printing", is activated by the signals of the sensors at the dryer.

6. Device according to claims 3 and 4 in which the control unit, in the mode of operation "thread-in", is activated by signals of the sensors at the dryer.

7. Device according to any one of claims 2-6 in which the roller, the press-down element, the drive, as well as the adjustment device are combined in one web handling unit.

8. Device according to any one of claims 1-7 in which the dryer comprises a pneumatic draw-in device.

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9. Device according to any one of claims 2-8 in which the roller, the pressdown element, as well as the adjustment device are arranged at the entrance of the-dryer--.

10. A devi,ce f or handling web material from a rotary printing machine, substantially as hereinbef ore described with reference to the accompanying drawings.