Composite Doctor Blade Chamber

Abstract

A composite doctor blade chamber (1) for a doctor blade chamber system for rotary printing units, the doctor blade chamber (1) including a front side with an open channel (8), wherein the doctor blade chamber is made of two composite profiles, an open profile (30) with a front side and a back side and a closed profile (33) with a front side and a back side, wherein the front side (31) of the open profile is joined with the back side of the closed profile (35), whereby is achieved low weight and high strength, high corrosion resistance, a cleaning-friendly surface, less waste of ink, nice appearance and an improved working environment. In addition it is an object of the invention to provide a doctor blade chamber system with the above mentioned advantages where re placement of doctor blades can be performed faster, more easily and without use of tools.

Claims

1. A method for making a composite doctor blade chamber that includes two composite profiles, wherein the method at least comprises the following step, wherein an open profile with a front side and a back side and a closed profile with a front side and a back side are joined between front side of the open profile and the back side of the closed profile.

2. A method for making a composite doctor blade chamber according to claim 1, wherein the front side of the open profile and the back side of the closed profile are joined by glue.

3. A method for making a composite doctor blade chamber according to claim 1, wherein at least part of the composite doctor blade chamber is made by means of one of the following processes: pultruding; moulding.

4. A composite doctor blade chamber made according to the method indicated in claim 1 for a doctor blade chamber system for rotary printing units, the doctor blade chamber including a front side with an open channel, wherein the doctor blade chamber further includes two composite profiles, an open profile with a front side and a back side and a closed profile with a front side and a back side, wherein the front side of the open profile is joined with the back side of the closed profile.

5. A composite doctor blade chamber according to claim 4, wherein the composite profiles at least include carbon fibres.

6. A composite doctor blade chamber according to claim 4, wherein the joining of the profiles includes glue.

7. A composite doctor blade chamber according to claim 4, wherein the composite doctor blade chamber includes a groove, preferably a T-shaped groove, at either side of and along the open channel.

8. A composite doctor blade chamber according to claim 4, wherein the composite doctor blade chamber at least includes a cleaning nozzle in the open channel.

9. A doctor blade chamber system for rotary printing units, including a doctor blade chamber, a clamping rail and a doctor blade, wherein the doctor blade chamber is a composite doctor blade chamber, and where the doctor blade is clamped between the clamping rail and the composite doctor blade chamber, the clamping action being provided by an elongated profiled rail with a first side engaging a groove in the clamping rail, preferably a T-shaped groove, and with a second side engaging a groove in the composite doctor blade chamber, preferably a T-shaped groove, wherein a resilient element displaces the profiled rail in the groove of the doctor blade chamber inwards in direction of the bottom of the doctor blade chamber groove, the resilient element including elastic foam provided between a wall of the doctor blade chamber groove, the wall being opposite the bottom of the doctor blade chamber groove, and the profiled rail, such that the foam by expansion urges the profiled rail in direction towards the bottom of the doctor blade chamber.

10. A doctor blade chamber system according to claim 9, wherein the doctor blade chamber system also includes a rigid oval tube that is rotatable about its longitudinal axis, the tube disposed between the bottom of the groove and the profiled rail in the groove, the rigid oval tube that is rotatable about its longitudinal axis counteracting the resilient foam when activated so that the doctor blade thereby is no longer clamped between the clamping rail and the composite doctor blade chamber.

11. A doctor blade chamber system according to claim 9, wherein the doctor blade chamber system also includes an elastic tube disposed in the groove of the composite doctor blade chamber between the bottom of the groove and the profiled rail in the groove, the elastic tube capable of pneumatically expanding and counteracting the resilient foam when activated so that the doctor blade thereby is no longer clamped between the clamping rail and the composite doctor blade chamber.

12. A doctor blade chamber system according to claim 11, wherein the doctor blade chamber system includes an air supply.

13. Use of a doctor blade system according to claim 9 for use in a printing unit, e.g. a flexographic printing unit.

Description

DESCRIPTION OF THE DRAWING

[0072] The invention will now be explained more closely in the following by description of non-limiting embodiments with reference to the drawing, where:

[0073] FIG. 1 shows a part of a doctor blade chamber according to prior art in perspective view;

[0074] FIG. 2 shows a cross-section of a doctor blade chamber according to prior art;

[0075] FIGS. 3a-b shows a cross-section through a part of a doctor blade chamber according to prior art where an elastic tube is used in the displacing mechanism;

[0076] FIGS. 3c-d shows a cross-section through a part of a doctor blade chamber according to prior art where a rigid oval tube that is rotatable about its longitudinal axis rail is used in the displacing mechanism;

[0077] FIG. 4 shows a cross-section through part of a doctor blade chamber according to prior art where the profiled rail is shaped so that the clamping rail may be lifted off the doctor blade chamber in an easy way;

[0078] FIG. 5 shows a composite doctor blade chamber according to the invention in a cross-sectional view where the two profiles are separated;

[0079] FIG. 6 shows a composite doctor blade chamber according to the invention in a cross-sectional view where the two profiles are joined;

[0080] FIG. 7 shows a composite doctor blade chamber according to the invention in a perspective view;

[0081] FIG. 8 shows a composite doctor blade chamber according to the invention in a cross-sectional view through a nozzle;

[0082] FIGS. 9a-d shows the same as FIGS. 3a-d where the wave spring is substituted by an elastic profile of foam polymer;

[0083] FIG. 10 shows the same as FIG. 4 where an elastic profile of foam polymer is also shown.

LIST OF DESIGNATIONS

[0084] 1 doctor blade chamber

[0085] 2 end piece

[0086] 4 doctor blade

[0087] 5 clamping rail

[0088] 6 bolt

[0089] 7 ink chamber

[0090] 8 open channel

[0091] 9 ink transfer roller

[0092] 10 surface of ink transfer roller

[0093] 11 part of the ink transfer roller inside the ink chamber

[0094] 14 groove in the doctor blade chamber

[0095] 15 groove in the clamping rail

[0096] 16 profiled rail

[0097] 17 interspace between one side of profiled rail and inner edge of the doctor blade chamber

[0098] 18 one side of profiled rail for disposing in doctor blade chamber groove

[0099] 19 inner edge of doctor blade chamber groove

[0100] 20 wave spring

[0101] 21 bottom of doctor blade chamber groove

[0102] 22 interspace between profiled rail and bottom of doctor blade chamber groove

[0103] 23 sidewall of doctor blade chamber groove

[0104] 24 elastic tube in interspace between profiled rail and bottom of doctor blade chamber groove, displacing mechanism

[0105] 25 internal volume of elastic hose

[0106] 26 eccentric tube, displacing mechanism

[0107] 27 resilient profile of foam polymer

[0108] 29 edge

[0109] 30 open profile

[0110] 31 front side, open profile

[0111] 32 back side, open profile

[0112] 33 closed profile

[0113] 34 front side, closed profile

[0114] 35 back side, closed profile

[0115] 36 foam

[0116] 37 nozzle aperture

[0117] 38 nozzle

[0118] 39 threaded insert

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0119] FIG. 1 is a schematic of a part of a doctor blade chamber 1 according to prior art in perspective view. For the sake of illustration, the doctor blade chamber 1 is shown without end casing normally sealing off the end part 2 so that the ink does not run out of the doctor blade chamber 1. A doctor blade 4 clamped between a clamping rail 5 and the doctor blade chamber 1 is mounted on the doctor blade chamber 1. Clamping rails 5 are screwed onto the doctor blade chamber 1 with bolts 6. Together with the doctor blades 4 the doctor blade chamber 1 constitutes the walls of the ink chamber 7. The open channel 8 between the doctor blades 4 is closed when the doctor blade chamber 1 is adjusted towards the ink transfer roller.

[0120] FIG. 2 shows a cross-section through the doctor blade chamber 1 according to prior art and an ink transfer roller 9. Together with the two doctor blades 4 touching the surface 10 of the roller, the ink chamber 7 is largely closed. When the ink transfer roller 9 rotates about its axis, the part of the roller 11 inside the ink chamber 7 collects ink which it gives off to other rollers in the printing unit. According to prior art, the clamping rails 5 are screwed onto the doctor blade chamber 1 with bolts.

[0121] FIGS. 3a and 3b show a cross-section through one side of the doctor blade chamber according to prior art for fixing a doctor blade 4, where the doctor blade chamber 1 is formed with a T-shaped groove 14 with bottom 21 and sidewalls 23, and the clamping rail 5 is formed with a groove 15 which is largely T-shaped. The latter groove 15 could also be T-shaped. The profiled rail 1 is designed so as to fit in the two grooves 14 and 15 such that the doctor blade chamber 1 and the clamping rail 5 are connected by mounting the profiled rail 16.

[0122] In the interspaces 17 between one T-shaped side 18 of the profiled rail and the inner edge 19 of the groove 14 of the doctor blade chamber, the inner edge 19 being the edge opposite to the bottom 21 of the doctor blade chamber groove 14, there is provided a wave spring 20 (shown by hatching) urging the inner edge 19 of the doctor blade chamber groove 14 and one T-shaped side 18 of the profiled rail away from each other so that the profiled rail 16 is displaced inwardly towards the bottom 21 of the groove. Hereby, a force is exerted on the clamping rail 5 against the doctor blade chamber 1, whereby the doctor blade 4 is clamped therebetween. There is furthermore a displacing mechanism including an elastic tube 24 in the interspace 22 between the profiled rail 16 and the bottom 21 of the doctor blade chamber, wherein the internal volume 25 of the elastic tube can be filled with gas which under pressure expands the elastic tube 24 (see FIG. 3b), counteracting the spring force, whereby the profiled rail 16 is pressed away from the doctor blade chamber bottom 21. The doctor blade 4 is thereby no longer clamped between the clamping rail 5 and the doctor beam 1 and can be removed.

[0123] As an alternative to the resilient tube 24, in the displacing mechanism can be used a rigid oval tube 26 that is rotatable about its longitudinal axis, see FIGS. 3c and 3d, disposed between the bottom 21 of the doctor blade chamber groove and the profiled rail 16. By rotating the tube 26, the profiled rail 16 is pressed away from the bottom 21 of the doctor blade chamber groove, whereby the clamping rail 5 is released from its clamping action.

[0124] FIG. 4 shows a cross-section through a part of the doctor blade chamber 1 in a further embodiment according to prior art for fixing a doctor blade 4. The profiled rail 16 in the clamping device is designed with an edge 29 that is similar to a hook in cross-section, engaging the clamping rail 5 so that the clamping rail 5 can be lifted off the profiled rail 16 when it is pressed outwards in direction away from the bottom 21 of the doctor blade chamber groove by means of a not shown displacing mechanism. This embodiment is an advantage in that mounting and dismounting of the clamping rail 5 can be performed easily and quickly, e.g. when the interspace between the doctor blade 4 and the clamping rail 5 or between the doctor blade 4 and the doctor blade chamber 1 is to be cleaned.

[0125] FIG. 5 shows a composite doctor blade chamber 1 in cross-section, by which it appears that the doctor blade chamber is made of two composite profiles that are shown separated in the form of an open profile 30 with a front side 31 and a back side 32, and a closed profile 33 with a front side 34 and a back side 35.

[0126] FIG. 6 shows a composite doctor blade chamber 1 according to the invention in cross-section, where it appears that the two composite profiles shown on FIG. 5 are assembled now as the front side 31 of the open profile is in contact with the back side 35 of the closed profile, wherein the two composite profiles are joined by means of e.g. glue. A T-shaped groove 14 is also seen on FIG. 6 at either side of and along the open channel 8, by which it also appears that part of the T-groove 14 is constituted by the open profile 30 and part of the T-groove 14 is constituted by the closed profile 33. In the embodiment shown here, the closed profile 33 contains a foam 36 with stabilising properties.

[0127] FIG. 7 shows a composite doctor blade chamber 1 according to the invention in perspective view, by which it appears that a number of nozzle apertures 37 are provided in open channel 8 at the front side 34 of the closed profile. The Figure also shows a number of threaded inserts 39 for application of various fastenings, fittings and the like.

[0128] FIG. 8 shows a composite doctor blade chamber 1 according to the invention and as shown in FIG. 7 seen in cross-section through a nozzle 38 mounted in a nozzle aperture 37, by which it appears that the nozzle aperture 37 goes through the doctor blade chamber 1 and is fastened at the back side 32 of the open profile 30.

[0129] FIGS. 9a-d basically show the same principle with displacing mechanisms as shown on FIGS. 3a-d, but where the doctor blade chamber 1 here is a composite doctor blade chamber and where the wave spring 20 in the interspace 17 between one side 18 of the profiled rail and the inner edge 19 of the doctor blade chamber has been replaced by an elastic profile of foam polymer 27 (shown hatched).

[0130] FIG. 10 basically also shows the same principle of the design of the profiled rail on FIG. 4, but where an elastic profile of foam polymer 27 (shown hatched) is provided and where the displacing mechanisms are omitted as well.