CN115674896A

CN115674896A - Powder spreading device

Info

Publication number: CN115674896A
Application number: CN202210553706.5A
Authority: CN
Inventors: C·哈斯; B·赫尔曼; M·莱瓦; A·朔尔普
Original assignee: Heidelberger Druckmaschinen AG
Current assignee: Heidelberger Druckmaschinen AG
Priority date: 2021-07-29
Filing date: 2022-05-19
Publication date: 2023-02-03
Also published as: DE102022116598A1

Abstract

The invention relates to a device for powdering printed sheets in a printing press, comprising a rotating rotary element for interrupting a powder jet (6) from a nozzle head (11). The nozzle head (11) is arranged outside the rotating element and the rotating element is configured as a shaft (9) with at least one row of grooves, for example through openings (12).

Description

Powder spreading device

Technical Field

The invention relates to a device for powdering printed sheets in a printing press, comprising a nozzle head and a rotating rotary element for interrupting a powder jet from the nozzle head.

Background

DE 197 07 157 A1 describes a dusting device in which a flap is provided, which can be pivoted back and forth, as is indicated by the double arrow in fig. 4 of the document. A nozzle is disposed outside the flip. In this document, a further powdering device is described, in which an orifice plate is provided which is pivoted in a direction indicated by the arrow in fig. 3 of this document. A nozzle is disposed within the orifice plate.

This results in a design which requires relatively much installation space, since the perforated plate must be large.

DE 10 2013 205 783 A1, DE 10 2011 084 026 A1, DE 12 52 a and DE 10 2011 012 A1 constitute further prior art.

Disclosure of Invention

The object of the invention is to provide a space-saving dusting device.

This object is achieved by a device for powdering printed sheets in a printing press, comprising a rotating rotary element which is swivelled in order to interrupt a powder jet from a nozzle head, characterized in that the nozzle head is arranged outside the rotary element and the rotary element is designed as a shaft with at least one row of recesses.

"slew" means: the rotary element performs a respective 360 ° continuous rotation in one direction only.

Since the nozzle head is located outside the shaft, the shaft can be designed compactly. The compact shaft results in a construction of the device which requires relatively little installation space.

Different developments are possible:

the shaft may be configured as a solid shaft.

The shaft can have two rows of openings, through which the aforementioned recesses are formed.

The shaft may be configured as a hollow shaft.

The shaft can have two rows of circumferential slots, by means of which the abovementioned grooves are formed.

The shaft may be disposed in the suction chamber.

A deflecting surface may be provided on the shaft.

The diverting surface may be concave.

Drawings

Further developments can also be taken from the following description of embodiments and the figures, in which:

FIG. 1 shows an overall view of a printing press;

fig. 2 shows a detail of the powdering device of the printing press;

fig. 3 shows a sectional view of a first rotational position of the dusting device;

fig. 4 shows a second rotational position of the powdering device;

FIG. 5 shows a shaft of the powdering device; and is

Fig. 6 shows a modification of the powdering device.

Detailed Description

Fig. 1 shows a printing press 1 with a sheet delivery 2. A dusting device 3 is provided in the sheet feeder 2.

Fig. 2 shows: the dusting device 3 dusts the printed sheets 4. The printed sheet 4 is transported in a transport direction TR. The dusting device 3 has a row of openings 5, from which a powder jet 6 is discharged onto the sheet 4. The powdering device 3 is provided with a suction air line 7 and a motor 8.

Fig. 3 shows: a shaft 9 is provided in the suction chamber 10 of the powdering device 3. The opening 5 opens into a housing wall of the suction chamber 10. The suction chamber 10 can be formed by a preferably rectangular hollow profile, for example a square tube.

A row of nozzle heads 11 extends parallel to the row of openings 5. The mouth of the nozzle head 11 is outside the circle of revolution of the shaft 9. The nozzle head 11 is inserted into the wall of the suction chamber 10. The opening 5 is aligned with the nozzle head 11 in the direction of the powder jet 6. The nozzle head 11 outputs the powder jet 6 into the suction chamber 10.

The shaft 9 is arranged in alignment with both the nozzle head 11 and the opening 5, wherein the geometrical rotation axis of the shaft 9 intersects all powder jets 6. The suction chamber 10 is connected to a vacuum generator by means of a suction air line 7 (fig. 2). A motor 8 (fig. 2) drives the shaft 9 in rotation. At a uniform printing speed of the printing press 1, the shaft 9 rotates in one direction at a uniform speed. However, it is also conceivable for the shaft 9 to rotate at a non-uniform speed at a uniform printing speed and for the shaft 9 to in particular be decelerated and accelerated again periodically in this case.

The shaft 9 serves here as a rotary valve which interrupts the introduction of the powder jet 6 into the opening 5 in the conveying rhythm of the printed sheet 4. All the powder jets 6 are transported from the shaft to the opening 5 in a first rotational position of the shaft 9 shown in fig. 3 and are not transported from the shaft to the opening in a second rotational position shown in fig. 4. In the first rotational position, the powder jet 6 passes through a groove provided in the shaft, which may be configured as a through-opening 12 (fig. 3 and 4) or as a circumferential slot 14 (fig. 5). The grooves form at least one row extending parallel to the geometric rotation axis of the shaft 9 or, preferably, a plurality of rows, which are evenly distributed along the circumference of the shaft 9. Within the or each row, the grooves are arranged at uniform distances from one another. This distance corresponds to the mutual distance of the openings 5 and also to the mutual distance of the nozzle heads 11.

In the first rotational position, one of the passing printed sheets 4 is opposite the powdering device 3, and in the second rotational position, a gap is formed between two successive printed sheets 4. In the second rotational position, the powder jet 6 impinges on the shaft 9 and the powder that bounces off the shaft 9 into the suction chamber 10 is sucked out of the suction chamber 10 via the suction air line 7.

In the variant shown in fig. 3 and 4, the shaft 9 is a solid shaft provided with two rows of radial through-holes 12 on diametrically opposite ends (or diametrically opposite). In the first rotational position (fig. 3), the powder jets 6 from the nozzle head 11 pass through the through-openings 12 and reach the openings 5, from which they are then discharged from the powdering device 3. In the second rotational position (fig. 4), the section 13 of the shaft 9 is in the beam path of the powder beam 6. These sections 13 are located between the openings 12 in the circumferential direction.

In the variant shown in fig. 5, the shaft 9 is designed as a hollow shaft with two circumferential rows of slots 14. In the first rotational position, each powder jet 6 flows through two circumferential slots 14 on diametrically opposite ends to the opening 5. In the second rotational position, the powder jet 6 is blocked by the webs 15 which are located in the pipe wall of the shaft 9 between the circumferential slots 14. The webs 15 are located between the circumferential slots 14 in the circumferential direction of the shaft 9.

Fig. 6 shows a modification which differs from the powdering device 3 shown in fig. 3 and 4 only in that a deflecting surface 16 is present on the shaft 9. When the shaft 9 is in the second rotational position, the respective deflection surface 16 deflects the powder jet 6 discharged from the nozzle head 11 into a separate region or block of the suction chamber 10. The powder air mixture can be concentrated in this separate area so that they can be better sucked out. In this case, preferably both the separate regions and the entire suction chamber are subjected to a vacuum. However, it is alternatively also possible to apply a vacuum only to the separate regions. The diverted powder jet 6 is indicated by an arrow in the figure.

The deflecting surfaces 16 are arranged at diametrically opposite ends with respect to one another and each lie between a section 13 and a passage 12. The deflecting surface 16 is concave and can be formed as a crescent or a concave arc or can be fixed as a blade on the shaft 9. The respective deflection surfaces 16 are preferably uninterrupted along the row of nozzle heads 10, which are common deflection surfaces 16 of the nozzle heads 10. However, it is alternatively also possible that the respective deflection surface 16 is formed by a row of partial surfaces with interruptions between them, wherein each partial surface is aligned with a different nozzle head 10 or a different group of nozzle heads 10.

List of reference numerals

1. Printing machine

2. Sheet delivery device

3. Powder spreading device

4. Printed sheet

5. Opening of the container

6. Powder jet

7. Suction air line

8. Motor with a stator and a rotor

9. Shaft

10. Suction chamber

11. Nozzle head

12. Piercing port

13. Segment of a motor vehicle

14. Circumferential slot

15. Tab

16. Surface of revolution

TR transport direction.

Claims

1. A device for powdering printed sheets (4) in a printing machine (1), comprising a rotating rotary element which is turned around to interrupt a powder jet (6) from a nozzle head (11), characterized in that the nozzle head (11) is arranged outside the rotary element and the rotary element is configured as a shaft (9) with at least one row of recesses.

2. The device according to claim 1, characterized in that the shaft (9) is constructed as a solid shaft.

3. Device according to claim 2, characterized in that the shaft (9) has two rows of through openings (12) forming the grooves.

4. The device according to claim 1, characterized in that the shaft (9) is configured as a hollow shaft.

5. The device according to claim 4, characterized in that the shaft (9) has two rows of circumferential slots (14) forming the grooves.

6. Device according to any one of claims 1 to 5, characterized in that the shaft (9) is arranged in a suction chamber (10).

7. A device according to any one of claims 1-6, characterised in that a diverting surface (16) is provided on the shaft (9).

8. Device according to claim 7, characterized in that the diverting surface (16) is concave.