The document WO 2006/035217 A1 discloses an ink distributor unit, which comprises an extruded profile provided with a chamber with doctor blades and with inlets and outlets. Fig. 5 shows a version of the ink distributor unit which is provided with a movable scraper element for cleaning the ink chamber. The extruded profile is extended with a space intended for a drive mechanism for the scraper element. The extension is secured to the chamber profile in a manner which is not described in detail. The purpose of the scraper element and of the configuration of the ink distributor unit is to establish an improved possibility of collecting and re-using as much as pos- sible of the excess ink in the chamber, e.g. when changing colour.

The document US 5,477,782 discloses an ink distributor unit which comprises a two chamber system (8, 9), fig. 1. The chamber (8) is connected with an ink source under pressure and with an ink chamber (9), which is disposed in close proximity to the printing roller. The unit is provided with a scraper (20) for removing excess ink, from which it drips down into an open collection trough (19).

The brochure "BPI sinus kammerrakel", published by the applicant, discloses an ink distribution system as stated in the opening paragraph. The excess ink is conveyed from the chamber down to an open collection tray and further on to an ink reservoir. The drawback of this system is that the vapours from the solvents of the ink may get mixed with the air in the surroundings, and that the ink dries unnecessarily with the result that it perhaps has to be discarded. Another drawback is that a collection tray in- volves extra cleaning work.

The object of the invention

It is the object of the invention to provide an ink distributor unit of the type mentioned in the opening paragraph, which is easy to manufacture, and which is easy to clean, make ready, mount and remove.

Another object of the invention is to enhance the rigidity of the ink distributor unit so that the deflection of the unit is reduced as much as possible.

A further object of the invention is to reduce waste of ink and the amount of harmful vapours.

Summary of the invention

The objects stated above are achieved by an ink distributor unit as described in the introductory portion of claim 1 , characterized in that one or more inlets pass transversely through the second chamber and terminate in the first chamber, and that channels are arranged between the chambers, said channels conveying excess ink from the first chamber to the second chamber, and that at least one outlet from the second chamber directs the excess ink further on to an external reservoir.

This makes it possible to use the second chamber as a collection chamber for excess ink, as the excess ink seeps back to the collection chamber via the channels between the first chamber and the second chamber. It is moreover ensured that the cleaning process is simplified, and that waste of ink and harmful vapours are reduced, as the excess ink is conveyed in closed channels between the chambers and further onto an external reservoir for ink.

When the first chamber and the second chamber extend along each other in close proximity to each other in the full length of the profile just separated by a wall, an ink distributor unit is achieved, which has a great rigidity, which is compact and relatively light, and where the channels between the chambers are as short as possible.

When, as stated in claim 2, the channels between the two chambers are arranged partly in a high position and partly in a low position, and the high position is above the level of the inlet for fresh ink, and the low position is below the inlet for fresh ink at the bottom of the first chamber, then the high position determines the maximum/optimum ink level in the first chamber, and the low position ensures that emptying of the first chamber takes place at stoppage or change of ink, and a further advantage is that a sufficient supply of ink to the raster roller may be maintained.

When, as stated in claim 3, the profile is configured such that the length of the profile corresponds to the length of a raster roller, and the profile and thereby the chambers are defined on the length of two tightly fitting end plates with stays for the suspension of the unit, then an ink distribution cov- ering the entire raster roller and a unit easy to mount and remove are achieved. When, as stated in claim 4, the engagement faces of the profile are configured for doctor blades with a groove which extends in the full length of the engagement faces for receiving a doctor clamp for clamping its respective doctor blade, it is ensured that the doctor blades may be mounted or re- moved merely by activating or releasing the doctor clamp, and that the doctor blades may be removed without the use of tools, e.g. at cleaning.

When, as stated in claim 5, the profile is provided with upper and lower grooves which extend in the full length of the profile, and which are config- ured for receiving a plurality of locking elements for locking a doctor clamp, and when, as stated in claim 6, the locking element comprises a bolt and a finger nut, it is ensured that the doctor clamp may be activated or deactivated by a simple rotation of the locking element. Finally, it is expedient, as stated in claim 7, that the doctor clamp is configured as an angular profile with a length like the profile and with an obtuse angle between the angle legs, and that the one angle leg is configured with a boss-like bulge in the full length of the angular profile, which protrudes into the area between the angle legs.

The drawing

Exemplary embodiments of the invention will be described more fully below with the reference to the drawing, in which fig. 1 shows a perspective view of an exploded ink distributor unit with associated end plates and doctor clamp, figs. 2, 2a and 2b show sectional views of the profile of the ink distributor unit, fig. 3 shows the connections between the first chamber and the second chamber, fig. 4 shows a sectional view of a doctor clamp profile, fig.5 shows a locking element, figs. 6 and 6a show hand tools, and figs. 7 and 7a show sealing elements. Detailed description of the invention

An ink distributor unit for applying ink to a raster roller for a rotary printing machine according to the invention is shown in figures 1 - 7.

Fig. 1 is a perspective view of an exploded ink distributor unit 1 with associated end plates 12 and doctor clamps 17. The distributor unit 1 is composed of a profile 2 which is provided with a trough 3 for ink and a second chamber 6 for collecting excess ink. The trough 3, together with the end plates 12 and with the doctor blades (not shown), which engage a raster roller (not shown), forms a first chamber 5. Both the first chamber and the second chamber are closed by the end plates 12. Channels 9, 10 are established between the two chambers 5, 6, which channels provide a safeguard against overflow, and which allow circulation of ink and emptying of the first chamber 5 at stoppage or change of ink.

Moreover, the profile 2 is configured with upper and lower engagement faces 4, 4a for the doctor blades. Figs. 2 and 2a show a sectional view of the profile 2. The profile has a length corresponding to the raster roller with which it is to be engaged. The figure shows the trough 3 which forms part of the first chamber 5, and that the second chamber 6 is arranged along and immediately behind the first chamber just separated by a wall 24. Both chambers have the same length as the profile 2 and thereby the same length as the raster roller.

The shown configuration of the profile ensures that the ink distributor unit has a great rigidity, so that the deflection of the unit is reduced consider- ably. This is especially important in case of tasks where the distribution of ink is to be carried out on roller lengths of 1700 - 3200 mm. Tests have shown that the deflection of an ink distributor unit of 3200 mm may be reduced to 1.5 tenths of a millimetre. In addition, the profile is provided with one or more inlets 7 which direct fresh ink from an external ink reservoir directly into the first chamber 5. The inlet 7 passes transversely through the second chamber 6 and terminates in the first chamber 5. Inlets which are not used for an assigned task, are closed off by a plug. The second chamber 6 is provided with one or more outlets 8 to an external ink reservoir.

The front edge of the profile is configured as engagement faces 4, 4a for the doctor blades. The engagement faces extend in the full length of the profile and are provided with grooves 15, 16 of the same length as the pro- file for receiving doctor clamps 17.

The upper and lower sides of the profile are likewise provided with grooves 22, 23 for receiving locking elements 21. The grooves extend in the full length of the profile.

The wall 24, which is shown in figs. 2, 2a and fig. 3, is provided with chan- nels 9, 10 which establish connections between the chambers 5, 6 and with an inlet opening 7. The chamber 5 is filled with ink in that ink is pumped from an external reservoir through the inlet 7. The supplied amount of ink must be adapted to the consumption, and it is important that the raster of the raster roller is constantly filled with ink. The consumption is determined by the size of the pressure face and by the speed at which the rotary printing machine operates.

To ensure that the amount of ink is sufficient during the entire printing process, the pump pressure is adjusted such that the first chamber 5 is filled to a high level determined by the channels 9. Excess ink will seep back to the second chamber 6, from which it is discharged via the outlet 8 to an external reservoir. In the event that the printing task requires a printing area which is smaller than the length of the ink distributor unit and of the printing roller, the active length of the chambers may be reduced by introducing plastics gaskets 25 into the first chamber and sealing elements 13 into the second chamber. The gaskets 25 are arranged in selected depressions 26 in the first chamber, and the sealing elements 13 are introduced to a desired position in the second chamber, by means of a hand tool 28 (see fig. 6a) configured as a threaded stay with a support plate and a handle. This allows blocking of areas of the chambers, so that unnecessary admission of ink is avoided, and the cleaning work and the consumption of cleaning liquid are reduced.

Channels 10 are arranged at a level lower than the inlet, which ensure circulation of ink back to the second chamber 6, and which are used for emptying the first chamber at stoppage or change of ink.

The end plates 12 are shown in fig. 1. A sealing element 13 (see fig. 7), which is provided with depressions for O-rings 13a, is secured by screws to the end plate on the side facing inwards toward the chambers. End plates and sealing elements are made of an aluminium alloy. On the opposite side, the end plate is provided with two stays 14 for the suspension of the distributor unit 1 from brackets on the printing machine. For cleaning, the distributor unit is lifted out of the printing machine. Then it is possible to pull the end plates 12 manually out of the profile by means of a simple hand tool 27 (see fig. 6), so that the chambers may be emptied completely and be cleaned.

The cleaning process has been simplified much with the distributor unit according to the invention. Thus, it is not necessary to arrange an open ink collection tray below the distributor unit, because the ink is encapsulated in the second chamber. Moreover, evaporation of the solvents in the ink and during the cleaning is reduced.

The doctor clamps 17 shown in fig. 1 , fig. 2b and fig. 4 are intended to secure the doctor blades and are configured as an angular profile with a length like the profile 2 and with an obtuse angle between the angle legs. The one angle leg is provided with a boss-like bulge 18, which extends in the full length of the angular profile, and which protrudes into the area between the angle legs. The doctor clamps are mounted in the profile 2 by moving the bulge 18 into the grooves 15 or 16. The clamps may now be tilted in the groove.

The doctor clamps 17 are activated or deactivated with one or more locking elements 21 shown in fig. 1 , fig. 2b and fig. 5. Each locking element comprises a bolt 20 with a hexagonal head and a disc-shaped finger nut 19. The bolts 20 are arranged in the grooves 22, 23, which are provided for receiving a bolt with a hexagonal head. When the bolt and the finger nut are screwed away from each other, the finger nut presses against the one angle leg of the doctor clamp, whereby the clamp tilts so that the other leg is pressed against the doctor blade and locks it. Conversely, the doctor blade is loosened by screwing the bolt and the finger nut closer together.