DE102018220528A1 - Method for operating a printing press - Google Patents

Abstract

In a method for operating a printing press sheets are conveyed with a chain gripper along a gripper bridge track (3) in a powder air channel (4). By a pneumatic seal (6), an air curtain (7) is emitted, which crosses the gripper bar web (3). In this case, at least one operating parameter of the pneumatic seal (6) is set as a function of at least one operating parameter of the printing press.

Description

The present invention relates to a method for operating a printing machine, being conveyed with a chain gripper along a gripper bridge track in a powder air duct sheets and a pneumatic curtain air curtain is emitted, which crosses the gripper bridge track.

In the third figure of the DE 196 43 747 A1 a device for applying a separation medium is shown on flat products. In this device, the products are conveyed by means of a conveyor below a foreclosure. At the outlet end of the foreclosure an axial fan is arranged, the downwardly directed air flow generates a kind of air curtain, which secures the separation medium from the conveying path, without this passes from the foreclosure in downstream sections of the conveying path.

The disadvantage of this is that the efficiency of the axial fan is not the same in all circumstances. For example, encapsulation at high machine speeds is not as good as low.

The invention has for its object to provide a method for operating a printing press, in which the pneumatic seal works equally well in different operating situations.

This object is achieved by a method for operating a printing machine, which conveyed with a chain conveyor along a gripper bridge path in a powder air duct sheets and a pneumatic curtain air curtain is emitted, which crosses the gripper bridge path, and wherein at least one operating parameter of the pneumatic seal in dependence is set by at least one operating parameter of the printing press.

An advantage of the method according to the invention is that the adjustment of the pneumatic seal is adapted to the respective operating situation and thereby the pneumatic seal acts optimally in every operating situation.

• Der mindestens eine Betriebsparameter der pneumatischen Dichtung kann ein Abstrahlwinkel des Luftvorhangs sein.
• Der mindestens eine Betriebsparameter der pneumatischen Dichtung kann ein Blasluftdruck sein.
• Der mindestens eine Betriebsparameter der Druckmaschine kann die Maschinengeschwindigkeit sein.
• Der mindestens eine Betriebsparameter der Druckmaschine kann das Format der zu verarbeitenden Druckbogen sein.
• Der mindestens eine Betriebsparameter der Druckmaschine kann die Grammatur der zu verarbeitenden Druckbogen sein.
• Hierbei kann bei leichter Grammatur ein flacher Abstrahlwinkel und bei schwerer Grammatur ein steiler Abstrahlwinkel eingestellt werden.
• Außerdem oder alternativ kann hierbei bei leichter Grammatur ein niedriger Blasluftdruck und bei schwerer Grammatur ein hoher Blasluftdruck eingestellt werden.
• Der Luftvorhang kann durch die pneumatische Dichtung im Transporttakt der Druckbogen abgestrahlt werden.
• Mit einer Absaugung kann in Transportrichtung der Druckbogen vor dem Luftvorhang Puderluft aus dem Puderluftkanal abgesaugt werden.

Various developments of the method according to the invention are possible:

• The at least one operating parameter of the pneumatic seal may be a radiation angle of the air curtain.
• The at least one operating parameter of the pneumatic seal may be a blown air pressure.
• The at least one operating parameter of the printing press may be the machine speed.
• The at least one operating parameter of the printing press can be the format of the printed sheets to be processed.
• The at least one operating parameter of the printing press can be the grammage of the printed sheets to be processed.
• This can be set with light grammage a flat beam angle and heavy grammage a steep beam angle.
• In addition or as an alternative, a low blowing air pressure can be set for light grammages and a high blown air pressure for heavy grammages.
• The air curtain can be radiated by the pneumatic seal in the transport cycle of the press sheets.
• With a suction can be sucked in the transport direction of the sheet in front of the air curtain powder air from the powder air duct.

• 1: eine Druckmaschine mit einer Vorrichtung zur Durchführung des erfindungsgemäßen Verfahrens und
• 2: eine Detaildarstellung der Vorrichtung aus 1.

Further developments will become apparent from the following description of an embodiment and the accompanying drawings, in which:

• 1 : a printing press with a device for carrying out the method according to the invention and
• 2 : a detailed view of the device 1 ,

1 shows a printing press 1 , in the sheet 5 be printed by offset printing or inkjet printing. The printing press 1 has a boom for laying out the printed sheets 5 on a pile. In the boom is a chain gripper 2 who the sheetfed 5 transported to the stack. The chain gripper 2 includes two endless chains that carry gripper bridges between them, covering the press sheets 5 Keep pinched at the front edge. The gripper bars move along a gripper bridge track 3 , The lower runs of the two chains run through a powder air channel 4 ,

In transport direction 9 (see. 2 ) the printed sheet 5 in front of the stack are the sheets 5 dusted with powder. The required pollination device is not shown in the drawing. Not on the sheet 5 sticking powder gets into the powder air duct 4 and gets from the chain gripper 2 carried away.

2 shows that the powder air duct 4 to a suction 8th is connected, so that the stray powder does not uncontrolled from the powder air duct 4 exit. The suction 8th flows into the ceiling of the powder air duct 4 , which also has a bottom and two side walls and is thus completely closed. In transport direction 9 after the suction 8th is a pneumatic seal 6 arranged an air curtain 7 ejects. Powdered air charged with the powder 10 in the powder air duct 4 gets through the air curtain 7 for suction 8th redirected. The pneumatic seal 6 prevents the escape of powdered air 10 from the powder air duct 4 and supports the suction 8th ,

The pneumatic seal 6 is designed as a blowpipe and the air curtain 7 extends over the entire width of the sheet 5 , The air curtain 7 is formed by a plurality of blast air jets which are ejected from a series of nozzles which enter the pneumatic seal 6 are introduced.

The pneumatic seal 6 pushes the air curtain 7 under a beam angle α relative to the gripper bridge track 3 in the powder air duct 4 out. She pushes the air curtain 7 against the transport direction 9 tilted off, the beam angle α is pointed. The size of the radiation angle α is due to a swing 13 the pneumatic seal 6 set by a drive 11 is adjusted. The drive 11 can be an electric motor or pneumatic cylinder and is controlled by a controller 12 driven.

The control 12 also controls a blast air device 14 on which the blown air of the pneumatic seal 6 controls. The blast air device 14 can z. Example, be an adjustable aperture with different hole diameters, by adjusting the nozzle cross section of the nozzle of the pneumatic seal 6 depending on one or more operating parameters of the printing press 1 can be varied. Instead of the orifice other valves or throttles can be used. The blast air device 14 can also be a blower, z. B. a compressor.

The control 12 is connected to or part of the central machine control and thus has access to the data and operating parameters of the printing machine 1 for the respective print job. For example, the controller has 12 Access to the data on the format and the grammage of the printed sheets 5 for the respective print job.

For example, the controller provides 12 For the processing of a heavy grammage (eg cardboard sheets) the beam angle α greater and / or the blowing air pressure of the pneumatic seal 6 higher than for processing a light grammage (eg paper sheet). The controller controls this 12 automatically to adjust the beam angle α the drive 11 and / or for adjusting the blowing air pressure, the blast air device 14 on.

In addition, the controller can control the beam angle α and / or vary the blast air pressure during the current print job as a function of the machine speed. For example, the controller 12 with an increase in the machine speed proportional to this increase the blown air pressure.

The control 12 can the blast air device 14 also with the transport cycle of the printed sheets 5 control synchronously, so that the blowing air is applied to the gaps between successive sheets 5 unlike the Blasluftbeaufschlagung the sheet 5 even done. For example, the blast air pressure may be during the passage of each gap in the air curtain 7 greater than during the passage of each signature 5 his.

According to a modification not shown in the drawing, a further suction is provided in the ceiling of the pneumatic seal 6 in the transport direction 9 following section of the powder air duct 4 empties.

With the method according to the invention, it is possible to operate the device at the optimum operating point, so that a maximum powder deflection is achieved with minimal arc disturbance.

LIST OF REFERENCE NUMBERS

1

press

2

chain gripper

3

Gripper rail

4

Powder air duct

5

sheet

6

pneumatic seal

7

air curtain

8th

suction

9

transport direction

10

powder air

11

drive

12

control

13

swing

14

blast air

α

Beam

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19643747 A1 [0002]

Claims (10)

Method for operating a printing machine (1), wherein print sheets (5) are conveyed along a gripper bridge web (3) in a powder air channel (4) by means of a chain gripper (2) and an air curtain (7) is emitted by a pneumatic seal (6), which intersects the gripper bar web (3), characterized in that at least one operating parameter of the pneumatic seal (6) is adjusted as a function of at least one operating parameter of the printing machine (1). Method according to Claim 1 , characterized in that the at least one operating parameter of the pneumatic seal (6) is a radiation angle (α) of the air curtain (7). Method according to Claim 1 or 2 , characterized in that the at least one operating parameter of the pneumatic seal (6) is a blown air pressure. Method according to one of Claims 1 to 3 , characterized in that the at least one operating parameter of the printing machine (1) is the machine speed. Method according to one of Claims 1 to 4 , characterized in that the at least one operating parameter of the printing press (1) is the format of the printed sheets (5) to be processed. Method according to one of Claims 1 to 5 , characterized in that the at least one operating parameter of the printing press (1) is the grammage of the printed sheets (5) to be processed. Method according to Claim 6 , characterized in that with light grammage a flat emission angle (α) and heavy grammage a steep emission angle (α) can be adjusted. Method according to Claim 6 or 7 , characterized in that at low grammage a lower blowing air pressure and heavy grammage a high blowing air pressure can be adjusted. Method according to one of Claims 1 to 8th , characterized in that the air curtain (7) through the pneumatic seal (6) in the transport cycle of the printing sheet (5) is emitted. Method according to one of Claims 1 to 9 , characterized in that with a suction (8) in the transport direction (9) of the sheet (5) in front of the air curtain (7) powder air (10) is sucked out of the powder air channel (4).

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