EP0528264B1 - Ink reservoir for feeding ink to a short-inking device in rotary offset printing machines - Google Patents

Description

The invention relates to an ink container for an ink supply for a short inking unit in offset rotary printing machines according to the preamble of claim 1.

In the case of inking units of offset rotary printing machines, in particular in the case of short inking units, it is known that the ink in the circuit between the doctor blade and the ink pump is continuously enriched with water. This leads to changes in the physical properties of the color. This can have adverse effects on print quality.

In order to mix the ink that has been scraped off the anilox roller with the paint that is partially freshly added in the ink fountain, it has been proposed in EP 01 82 325 to introduce the scraped paint into an area of the ink fountain that is far away from the removal point in the ink fountain, by means of an immersion roller . This relatively long path should result in a good mixing and mixing of the ink scraped off from the doctor roller and back into the ink tank with the ink in the ink tank.

However, this device mentioned is defective in that the returning ink, which has a different viscosity than the one in the ink tray, does not mix on its way from the baffle until it is removed by the dip roller, since the viscosity difference is too great.

The invention has for its object to provide an ink container for an ink supply for a short inking unit in offset rotary printing machines, with which a continuous supply of portions of new ink and portions of ink doctored by the anilox roller takes place.

This object is achieved according to the characterizing part of patent claim 1. Appropriate configurations can be found in the subclaims.

The advantages of the inking unit according to the invention for offset rotary printing machines consist in particular in that only a small amount of ink is in circulation due to the smaller volume of the circulation chamber compared to the storage chamber. Only the ink used in the circulation chamber runs continuously from the storage chamber. This ensures that the physical printing properties of the ink are retained for the offset process.

Fig. 1

die schematische Ansicht eines erfindungsgemäßen Farbwerkes mit geteiltem Farbbehälter;

Fig. 2

eine zweite Ausführungsform des Farbbehälters;

Fig. 3

eine dritte Ausführungsform des Farbbehälters;

Fig. 4

eine vierte Ausführungsform des Farbbehälters;

Gemäß Fig. 1 ist eine insgesamt mit 1 bezeichnete Kammerrakel unterhalb einer Rasterwalze 2 angeordnet. Die Kammerrakel 1 sowie die Welle der Rasterwalze 2 sind in nicht dargestellten Seitenwänden eines Maschinengestells gehalten. Über einen Anschlußstutzen 3 besitzt die Kammerrakel 1 eine symbolisch durch eine Mittellinie dargestellte Farbzuführung 4, welche mit dem Anschlußstutzen 6 einer Farbpumpe 7 in Verbindung steht. Die Farbpumpe 7 befindet sich zusammen mit einem angeflanschten Motor 8 auf einer Grundplatte 9. Auf einem der Grundplatte 9 gegenüberliegenden Einlaßstutzen 11 der Farbpumpe 7 befindet sich ein geteilter Farbbehälter 12, welcher einen im wesentlichen trichterförmigen Querschnitt besitzt und an seinem umgebördelten Fußteil 13 mittels eines Gewindeflansches 14 auf dem mit Gewinde versehenen Einlaßstutzen 11 der Farbpumpe 7 befestigt ist. Der sich nach oben verbreiternde Trichter des Farbbehälters 12 ist mittels einer Trennwand 16 in eine Speicherkammer 17 und eine Umlaufkammer 18 unterteilt. Die Trennwand 16 verläuft parallel zur senkrechten Seitenwand 19 des Farbbehälters 12 und erstreckt sich in axialer Richtung zur Rasterwalze 2. Die Trennwand 16 ist fest mit der Außenwand des Farbbehälters 12, beispielsweise durch Schweißnähte, verbunden. Zwischen dem unteren Ende der Trennwand 16 und dem Boden des Farbbehälters 12 befindet sich ein Durchlaß 21, der die Speicherkammer 17 mit der Umlaufkammer 18 verbindet. Die Speicherkammer 17 enthält neu zugeführte Druckfarbe, welche durch die Niveaulinie 22 sichtbar gemacht ist. Die Trennwand 16 kann jedoch auch in vertikaler Richtung hin- und herbewegbar in Art eines mit seitlichen Führungen versehenen Schiebers ausgeführt sein, so daß der Durchlaß 21 einstellbar ist.The invention will be explained below using several exemplary embodiments. Show in the accompanying drawings

Fig. 1

the schematic view of an inking unit according to the invention with a divided ink tank;

Fig. 2

a second embodiment of the paint container;

Fig. 3

a third embodiment of the paint container;

Fig. 4

a fourth embodiment of the paint container;

1, a chamber doctor blade, generally designated 1, is arranged below an anilox roller 2. The chamber doctor blade 1 and the shaft of the anilox roller 2 are held in side walls of a machine frame, not shown. Via a connecting piece 3, the doctor blade 1 has an ink supply 4 symbolically represented by a center line, which is connected to the connecting piece 6 of an ink pump 7. The paint pump 7 is located together with a flange-mounted motor 8 on a base plate 9. On an inlet connection 11 of the paint pump 7 opposite the base plate 9 there is a divided paint container 12 which has an essentially funnel-shaped cross section and on its flanged base part 13 by means of a threaded flange 14 is attached to the threaded inlet port 11 of the paint pump 7. The funnel of the paint container 12 which widens upwards is divided into a storage chamber 17 and a circulation chamber 18 by means of a partition wall 16. The partition 16 runs parallel to the vertical side wall 19 of the ink container 12 and extends in the axial direction to the anilox roller 2. The partition 16 is firmly connected to the outer wall of the ink container 12, for example by welds. Between the lower end of the partition 16 and the floor of the paint container 12 there is a passage 21 which connects the storage chamber 17 with the circulation chamber 18. The storage chamber 17 contains newly supplied printing ink, which is made visible by the level line 22. The dividing wall 16 can, however, also be designed to be movable back and forth in the manner of a slide provided with lateral guides, so that the passage 21 can be adjusted.

In the circulation chamber 18 there is the liquid which has been doctored off by the anilox roller 2 and which consists of ink and water and which leaves the doctor blade 1 in the direction of arrow A and is collected in the circulation chamber 18. Due to the different viscosities of the in the two chambers 17; 18 liquids, the fill level in the circulation chamber 18 is lower, which is made visible by the level line 23.

During the operating state, i.e. H. Movement of the anilox roller 2 in the direction of arrow A, a water-ink mixture is fed in the direction of arrow A to the circulation chamber 18 of the ink container 12. By means of the ink pump 7, said mixture is supplied with a proportion of new ink from the storage chamber 17 through the passage 21 of the chamber doctor blade 1 via the ink supply. This arrangement ensures a continuous and even supply of portions of new ink and portions of components scraped off the anilox roller. In addition to the anilox roller 2 there is still a dampening unit, not shown.

2 to 4, further embodiments of divided paint containers 12 are shown, which are in the Differentiate between the design and fastening of the partition. Thus, a partition 24 is shown in Fig. 2, which has at its lower end a strip 26 made of flexible material, such as rubber, which is fastened to the partition 24 by means of rivets 27, so that in turn a passage 21 can be formed. The attachment must be form-fitting and can also be done otherwise.

3, the chambers 17; 18 of the paint container 12 divided by a partition wall 28, which is mounted on its side facing the funnel opening in pivot points 29 in the direction of arrow A. This can also result in a passage 21, not shown, as shown in FIG. 2.

According to FIG. 4, the partition is initially firmly connected to the paint container 12 as in FIG. 2. At the lower part of the partition 31 there is a strip 33 mounted in articulation points 32 which can be opened against the force of a tension spring 34 so that a passage 21 can be created.

Parts list

1

Chamber squeegee

2nd

Anilox roller

3rd

Connecting piece

4th

Ink feed

5

-

6

Connecting piece

7

Paint pump

8th

engine

9

Base plate

10th

-

11

Inlet connector

12th

Paint container

13

Base

14

Threaded flange

15

-

16

partition wall

17th

Storage chamber

18th

Circulation chamber

19th

Side wall

20th

-

21

Passage

22

Level line

23

Level line

24th

partition wall

25th

-

26

strip

27

rivet

28

partition wall

29

pivot point

30th

-

31

partition wall

32

Hinge point

33

Stripes

34

Tension spring

A

Arrow direction

Claims (11)

1. Ink reservoir (12) for mixing offset printing ink comprising a mass flow of wiped-off, returned printing ink containing damping medium and a mass flow of newly supplied printing ink, the mixed-ink flow being fed to a metering device of a short inking unit (12; 4; 2; 1) by means of a pump (7), characterised in that the ink reservoir (12) has, separated from one another, a first chamber (18) for receiving the returned mass flow and a second chamber (17) for receiving the supplied mass flow, in that the first chamber (18) and the second chamber (17) are connected to one another via an opening (21).
2. Ink reservoir according to Claim 1, characterised in that the opening (21) has a variable cross-section.
3. Ink reservoir according to Claims 1 to 2, characterised in that the first chamber (18) and second chamber (17) are separated from one another by means of a dividing wall (24) having the opening (21).
4. Ink reservoir according to Claims 1 to 3, characterised in that the opening (21) is arranged at the lower end of the dividing wall (24).
5. Ink reservoir according to Claims 3 and 4, characterised in that the dividing wall (24) has at its lower end a flexible strip (26) positively connected to the dividing wall (24).
6. Ink reservoir according to Claims 3 and 4, characterised in that the dividing wall (28) is pivotably mounted at its upper side (29) facing the funnel opening.
7. Ink reservoir according to Claims 3 and 4, characterised in that the dividing wall (31) has at its lower side facing the funnel outlet a strip (33) which is pivotable at hinge points (32) fixed to the dividing wall and is movable against the force of tension springs (34).
8. Ink reservoir according to Claim 3, characterised in that the ink reservoir (12) has substantially a funnel shape and is detachably connected to an inlet connection (11) of an ink pump (7).
9. Ink reservoir according to Claims 1 to 8, characterised in that a chamber doctor (1) is provided as ink-metering device.
10. Ink reservoir according to Claims 1 to 9, characterised in that the ink reservoir (12) has a width corresponding to half or alternatively a quarter of the length of a roller (2) to be inked by means of the ink-metering device (1).
11. Ink reservoir according to Claims 1 to 10, characterised in that the first chamber (18) opens into the inlet connection (11) of the ink pump (7).

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