Field of the Invention

The present invention relates to a method for cleaning of newly produced plate-shaped cliches made from a rubber web or substrate and of the type as defined in the pream- ble to claim 1.

The invention also relates to a cleaning apparatus for carrying out the method for cleaning of plate-shaped cliches.

Background of the Invention

Known cleaning methods and processes comprise a cleaning chamber where cleaning fluid is applied to a plate-shaped cliche while simultaneously the plate-shaped cliche is brushed with a soft brush. The cleaning chamber is part of a closed circuit where the cleaning fluid is recirculated from and to a receptacle. After the cleaning chamber the plate-shaped cliche passes another cleaning chamber where the plate-shaped cliche is flushed with fresh cleaning fluid and dried. The latter is carried out by means of a special sponge roller acting at the same time as a wet cloth and a sponge. US 2009/0013888 Al discloses a method for feeding a photopolymerised elastomeric printing plate, subsequent to exposure and washing out thereof, along a path through a rinsing station, comprising: optionally providing a plate assembly comprising the plate and, supporting the plate, a carrier having a pair of opposed peripheral regions each extending laterally beyond respective opposed lateral edge regions of the plate, providing, transversely of the path, at least one pair of driven rollers defining a nip there between through which the plate can pass so as to be forwarded along the path by frictional engagement of the plate or palter assembly with each of the driven rollers within the nip, at least one of which rollers is profiled so as to allow contact of the profiled roller with the opposed lateral edge regions of the plate or, when provided, corresponding opposed peripheral regions of the plate assembly, thereby to allow the said frictional engagement, but to allow freedom from contact of the plate with the or each profiled roller at an interior region of the plate between the said regions in con- tact with the or each profiled roller, and feeding the plate, or optionally when provided, the plate assembly, by the driven rollers along the path through the rinsing station.

Object of the Invention

In the printing industry a quite new development is that as the prices for acquiring rather complicated laser cutting devices has been lowered more printing business acquires rather complicated laser cutting system for the production of plate-shaped cliches by themselves and therefore it is the purpose of the present invention to provide an improved method for the cleaning of plate-shaped cliches where special adaptions of the known method is achieved by adding a high-pressure.

Description of the Invention

According to the invention the method for cleaning of plate-shaped cliches is characterised in comprising the further actions

- feeding the plate-shaped cliches into and through a high-pressure cleaning chamber situated between said first cleaning chamber and said other cleaning chamber;

- flushing in said high-pressure cleaning chamber a high-pressure cleaning fluid at a range of 30-120 bar to at least said print side of the plate-shaped cliches.

By a rather simple method and means it hereby becomes possible to obtain sufficient cleaning of newly produced plate-shaped cliches made from a rubber web or substrate (EPDM) by which the printing side in advance has been laser cut with the desired printing pattern whereby sufficient removing of the resulting EPDM dust can be effectively flushed of and removed from the front side of the plate-shaped cliches by an effective and safe continuously cleaning process.

In order to obtain an improved method for cleaning plate-shaped cliches according to the invention it can be advantageous to make use of combined transport and separation rollers preferably made from semi-hard rubber at an entrance to and at an outlet from said first cleaning chamber and said high-pressure cleaning chamber.

Such semi-hard rollers has a double function namely to act both as transportation roller for the continuously moving of the plate-shaped cliches through the respective cleaning chambers and at the same time to prevent the cleaning fluid to escape from the cleaning chambers along the plate-shaped cliches.

Because of the semi-hard rubber material the semi-hard surface of the rubber rollers is able to act as a continuous barrier following the surface pattern of the printing surface of the plate-shaped cliches.

It may furthermore be advantageous that said cleaning brushes of said primary cleaning chamber are reciprocating perpendicular to the direction of movement of the plate- shaped cliches.

In order to optimize and simplify the method for cleaning plate-shaped cliches according to the invention may by modified by using fresh water as cleaning fluid in said high-pressure cleaning chamber.

The present invention also relates to a cleaning apparatus for cleaning plate-shaped cliches comprising a first cleaning chamber where said plate-shaped cliches are fed through an entrance opening onto a carrier surface supporting the rear side of the plate-shaped cliches, when the print side of the plate-shaped cliches is brushed by means of cleaning brushes and at the same time the plate-shaped cliches are flushed by cleaning fluid applied from nozzles before leaving the first cleaning chamber through an outlet opening, and are then fed through an entrance opening to another cleaning chamber comprising a subsequent flushing and drying zone with a drying sponge roller and a hot air blower, which cleaning apparatus is characterised in com- prising a high-pressure cleaning chamber for applying high-pressure cleaning fluid to said plate-shaped cliches, said high-pressure cleaning chamber is placed between said first cleaning chamber and said other cleaning chamber.

By a rather simple apparatus - as seen from a technical point of view - it hereby becomes possible to obtain both an effective and a sufficient cleaning of plate-shaped cliches by which the printing side in advance has been laser cut with the desired printing pattern, whereby sufficient removing of the resulting EPDM dust can be effectively flushed of and removed from the front side of the plate-shaped cliches by an effective and safe continuously cleaning process. The cleaning apparatus according to the invention may be such provided that said entrance opening and said outlet opening being provided with combined transport and separation rollers made from semi-hard rubber or a similar elastic material.

As mentioned above such semi-hard rollers has a double function namely to act both as transportation roller for the continuously moving of the plate-shaped cliches through the respective cleaning chambers and at the same time to prevent the cleaning fluid to escape from the cleaning chambers along the plate-shaped cliches.

In order to support the recirculation and reuse of the cleaning fluid it may be advantageous that the apparatus according to the invention is such provided that each cleaning chambers are provided with lower funnel-shaped drainage openings through which cleaning fluid from the respective chamber is collected and led to receptacles or tanks, since the cleaning fluid preferably is recirculated and reused in the respective chambers.

Advantageously the cleaning apparatus according to the invention may be such provided that said other cleaning chamber also comprises an entrance opening provided with combined separation and transport rollers made from semi-hard rubber or a similar elastic material.

In order to optimize and simplify the cleaning process the cleaning apparatus according to the invention may be such provided that said high-pressure cleaning chamber is adapted to use cleaning fluid preferable in the form of fresh water applied to the front or print side of the plate-shaped cliches through one or more nozzles for high-pressure cleaning fluid.

Description of the Drawing

The invention is explained in more details with reference to the accompanying drawing in which:

Fig. 1 shows a plane view illustrating schematically a prior art cleaning method for cleaning of plate-shaped cliches, Fig. 2 shows a plane view illustrating schematically an embodiment of an improved cleaning method for cleaning plate-shaped cliches according to the invention,

Fig. 3 shows a perspective view of an embodiment for a cleaning apparatus for cleaning plate-shaped cliches according to the invention - shown with a high- pressure cleaning chamber exposed (without top cover),

Fig. 4 shows a perspective view of the cleaning apparatus for cleaning plate-shaped cliches cf. Fig. 3 with the high-pressure cleaning chamber closed by a hood- shaped top cover,

Fig. 5 shows a perspective view of another embodiment for a cleaning apparatus according to the invention, and

Fig. 6 shows a perspective view showing the respective chamber parts of the cleaning apparatus cf. Fig. 5 according to the invention.

Detailed Description of the Invention

In Fig. 1 is shown a prior art cleaning method where a plate-shaped cliche 2 is cleaned by means of a cleaning apparatus as the plate-shaped cliche 2 is feed into a first cleaning chamber 4 through an entrance opening 34 provided with combined transport and separation rollers 14 made from semi-hard rubber or a similar elastic material such that the combined transport and separation rollers 14 at the same time take care of the continuously transport of the plate-shaped cliche 2 and the holding back the cleaning fluid from streaming out along the upper surface of the plate-shaped cliche 2, since the latter also leaves the first cleaning chamber 4 through an outlet opening 36 provided with combined transport and separation rollers 14 made from semi-hard rubber or a similar elastic material.

In said first cleaning chamber the upper printing side of cliche 2 is brushed by mean of reciprocating cleaning brushes 16 and at the same time cleaning fluid is applied to the upper surface of the cliche 2 from nozzles 10. The cleaning brushes 16 are reciprocating perpendicular to the direction of movement of the cleaning brushes 16 indicated with arrows 18. From said first cleaning chamber 4 the cliche 2 leaves the chamber through an outlet opening 36 and into another cleaning chamber 6 through an entrance opening 34 similar to that of said first cleaning chamber 4. In the other cleaning chamber 6 the cliche 2 is again flushed with cleaning fluid before leaving the other cleaning chamber 6 when passing a drying zone with a drying sponge roller 24 and a hot air blower 26.

Both the first and the other cleaning chambers 4, 6 are in the bottom provided with lower funnel-shaped drainage openings 28, 30 through which the cleaning fluid is collected and lead to receptacles or tanks as preferably the cleaning fluid is recirculat- ed and reused in the respective cleaning chambers 4, 6.

Fig. 2 shows a schematically plane view of an embodiment for a cleaning apparatus 3 for carrying out the method according to the invention and consequently the cleaning apparatus 3 comprising a first cleaning chamber 4 and another cleaning chamber 6 - however between the first and other cleaning chambers 4, 6 is built-in a high-pressure cleaning chamber 8 so that a plate-shaped cliche 2 can be continuously feed through three successively arranged cleaning chambers 4, 6, 8.

In this connection is important to be aware of that the size the plate-shaped cliches 2 in question may differ rather dramatically from a small size of 100 x 100 mm to a medium size of 2000 x 3000 mm - or maybe even a special size of 2000 mm x endless. In other words such plate-shaped cliches 2 may have any configuration including rectangular or squared. And in the cleaning apparatus 3 the front or print side of the cliches 2 are always facing upwards towards the reciprocating brushes 16 of the first cleaning chamber 4 and the high-pressure nozzles 20 of the high-pressure cleaning chamber 8.

The high-pressure cleaning chamber 8 has an entrance opening 34 with combined transport and separation rollers 14 and an outlet opening 36 also with combined transport and separation rollers 14 - the special double function of these combined transport and separation rollers 14 is previously explained.

Figs 3-6 show further embodiments for a cleaning apparatus 3 according to the invention, where the specific apparatus parts are designated with the same reference numbers as appear from the glossary. Glossary - reference numbers used in the drawings

2 plate-shaped cliche

3 cleaning apparatus for carrying out the method according to the invention

4 first cleaning chamber

6 other cleaning chamber

8 high-pressure cleaning chamber

10 nozzles for cleaning fluid

12 hood-shaped top cover for high-pressure cleaning chamber

14 combined transport and separation rollers made from semi-hard rubber 16 cleaning brushes is reciprocating perpendicular to the direction of movement of the plate-shaped cliches

18 arrows showing the direction of movement of the plate-shaped cliches

20 nozzles for high-pressure cleaning fluid (water)

22 carrier surfaces for plate-shaped cliches

24 drying sponge roller

26 hot air blower

28 lower funnel-shaped drainage opening from first cleaning chamber

30 lower funnel-shaped drainage opening from other cleaning chamber

32 lower funnel-shaped drainage opening from high-pressure cleaning chamber 34 entrance opening of first cleaning chamber and high-pressure cleaning chamber

36 outlet opening of first cleaning chamber and high-pressure cleaning chamber