Sealing assembly for an ink chamber which includes self-lubricating anilox roll seal with improved blade/seal area

Abstract

A sealing assembly for an ink chamber associated with an anilox roll, includes a doctor blade having a doctoring edge, with each end having a notch at the doctoring edge, and first and second seals adapted to seal ends of the ink chamber. Each seal includes a peripheral supporting wall, an upper wall thereon including an upper concave surface for engaging an outer surface of the anilox roll, a flat upper supporting surface at opposite ends of the upper wall on which ends of the doctor blade seat, and an extension above the flat upper supporting surface for engaging within the notch at the end of the doctor blade to permit the doctor blade to bend thereat. A lubricant chamber is defined therein and the upper wall includes an opening through which the lubricant is forced out of the lubricant chamber due to external pressure.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of doctor and sealing blade seal according to the present invention;

FIG. 1A is a perspective view of doctor and sealing blade seal according to another embodiment of the present invention;

FIG. 2 is a side elevational view the doctor and sealing blade seal of FIG. 1;

FIG. 3 is a top plan view of the doctor and sealing blade seal of FIG. 1;

FIG. 4 is a cross-sectional view of the doctor and sealing blade seal of FIG. 3, taken along line 4-4 thereof;

FIG. 5 is a cross-sectional view of the doctor and sealing blade seal of FIG. 3, taken along line 5-5 thereof;

FIG. 6 is a cross-sectional view of the doctor and sealing blade seal of FIG. 3, taken along line 6-6 thereof;

FIG. 7 is a cross-sectional view of the doctor and sealing blade seal of FIG. 3, taken along line 7-7 thereof;

FIG. 8 is an end elevational view of the doctor and sealing blade seal of FIG. 1;

FIG. 9 is a plan view of the end portion of a doctor/sealing blade according to the present invention;

FIG. 10 is a perspective view of the seal assembly with the doctor blade and sealing blade assembled with the doctor and sealing blade seal; and

FIG. 11 is a cross-sectional-view of a conventional doctor and sealing blade seal in association with an anilox roll.

DETAILED DESCRIPTION

Referring to the drawings in detail, and initially to FIG. 11 thereof, there is shown a conventional doctor and sealing blade sealing assembly 10. Conventionally, in printing machines, such as flexographic printing machines, an ink transfer or anilox roll 12 transfers ink to an adjacent plate roll (not shown) for printing. Ink is supplied to anilox roll 12 from an ink chamber 14 defined by a chamber housing 16 which is adjacent to and may partially surround anilox roll 12. Anilox roll 12 rotates in the direction of arrow 12a.

In order to prevent the escape of ink from ink chamber 14, while ensuring that the ink enters the cells in anilox roll 12 and has a predetermined volume on anilox roll 12, sealing and doctor blades 18 and 20 are provided at the entry and exit positions of anilox roll 12 relative to ink chamber 14. Blades 18 and 20 are fixed to chamber housing 16 by an blade holder (not shown) so that blades 18 and 20 overhang chamber housing 16 and contact anilox roll 12. Blades 18 and 20 are placed at an angle against the periphery of anilox roll 12 and help to define ink chamber 14 which extends along the length of anilox roll 12.

Seals 22 are provided at each end of anilox roll 12 to seal the ends of ink chamber 14. Each seal 22 has an upper concave surface 22a which lies against the peripheral surface of the rotating anilox roll 12. The edges of upper concave surface 22a continue in downwardly sloping flat supporting surfaces 22b and 22c which support blades 18 and 20, respectively.

With this arrangement, the outer surface of anilox roll 12 passes through ink chamber 14 and picks up ink for printing. The ink is metered by means of doctor blade 20 held to the outlet end of chamber housing 16, and sealed with sealing blade 18 held to the inlet end, with the free ends of blades 18 and 20 being in contact with the outer surface of anilox roll 12.

However, because each end of blades 18 and 20 sits upon a flat supporting surface 22a or 22b of a respective seal 22, there is not much “give” or flexibility at the ends of each blade 18 and 20 where it is held by seals 22. For example, when a blade 18 or 20 is pressed down by air and other forces at its center, the blade cannot bend a great amount and there is much pressure on the blade. Because there is more force by seals 22 on each blade 18 and 20 at the ends thereof where they are held, they are less capable of flexing or bending at these points. As a result, there is uneven wear of blades 18 and 20 adjacent seals 22, which tends to cause more wear and more leakage of ink at the ends of anilox roll 12. Further, ink scraped by blades 18 and 20 tends to ride under the blades, that is, between blades 18 and 20 and flat supporting surfaces 22a and 22b of seals 22, causing blades 18 and 20 to lift up away from seals 22, thereby resulting in still more leakage.

If a seal 22 is lubricated, blades 18 and 20 will not wear as much in the seal areas as compared to an area outside of seal 22. On the other hand, if a seal 22 is not lubricated, the dried ink will wear blades 18 and 20 faster at flat supporting surfaces 22a and 22b. In either case, the areas where anilox roll 12, blades 18 and 20 and seals 22 join are susceptible to leakage because of geometric changes.

In accordance with a first aspect of the present invention, as shown in FIGS. 1-10, a blade/ink chamber seal 122 for use in a sealing assembly according to the present invention for use with an anilox roll 112 and sealing blade 118 and doctor blade 120, includes spaced apart side walls 122d and 122e connected together at upper ends thereof by an upper wall 122f having an upper surface 122a which continues in inlet and outlet downwardly sloping flat upper blade supporting surfaces 122b and 122c that support blades 118 and 120, respectively. The opposite ends of downwardly sloping flat upper blade supporting surfaces 122b and 122c are connected to spaced apart end walls 122g and 122g, and side edges thereof are connected to side walls 122d and 122e. As a result, a lubricant chamber 113 is defined between side walls 122d and 122e, upper wall 122f and end walls 122g and 122g. There is no bottom wall because the lower ends of side walls 122d and 122e and end walls 122g and 122g, form a seal along a wall 16a (FIG. 11) of chamber housing 16, which effectively functions as the bottom wall thereof.

In accordance with the present invention, upper surface 122a is formed by two spaced apart upper concave surface portions 122a1 and 122a2, with an intermediate upper wall portion 122a3 therebetween. Each upper concave surface portion includes blade engaging extensions 122i and 122j at opposite ends thereof which extend directly above downwardly sloping flat upper blade supporting surfaces 122b and 122c and which follow and continue the same curvature as upper concave surface portions 122a1 and 122a2. However, it will be appreciated that blade engaging extensions 122i and 122j need not follow and continue the same curvature as upper concave surface portions 122a1 and 122a2. Thus, there are two such blade engaging extensions 122i on one side of seal 122 which are positioned in spaced apart relation above downwardly sloping flat upper blade supporting surface 122b and there are two such blade engaging extensions 122j on the opposite side of seal 122 which are positioned in spaced apart relation above downwardly sloping flat upper supporting surface 122c.

In correspondence therewith, each blade 118 and 120, as shown best in FIGS. 9 and 10, is provided with two spaced apart notches 123 and 124 at each end and along the same lengthwise doctoring/sealing edge 126, thereby defining a flat generally rectangular cantilevered tab 128 therebetween. When blades 118 and 120 are assembled in the sealing assembly, the two spaced apart notches 123 and 124 receive two adjacent blade engaging extensions 122i or 122j on one side of each seal 122. Tab 128 thereby rests on and seals against the respective downwardly sloping flat upper blade supporting surface 122b or 122c. As a result, the main central portion 130 of each blade 118 and 120 which extends between notches 123 at opposite ends thereof, is permitted to bend relative to seal 122. Thus, even though the end portion 132 of each blade 118 and 120, that is, the portion other than main central portion 130 which contains notches 123 and 124 and tab 128, is held flush with downwardly sloping flat upper blade supporting surface 122b or 122c, main central portion 130 can flex or bend relative thereto. During such bending, the side edge 130a of main body 130 defined by cut-out notch 123 bends or folds down and scrapes along the inner facing side wall surface 111 of side wall 122d so as to provide an effective sealing arrangement thereat. In addition, notches 123 and 124, along with blade engaging extensions 122i or 122j, serve to properly align blades 118 and 120 on each seal 122.

This means that blades 118 and 120 can bend just as easily at their ends in the same manner as they can bend at their center portions so that any wear along doctoring/sealing edge 126 will wear evenly. In addition, any caked ink that travels between downwardly sloping flat upper blade supporting surfaces 122b and 122c and blades 118 and 120 will not affect the sealing relation since the side edges 130a of blades 118 and 120 will still provide an effective sealing arrangement against inner facing side wall surface 111 of side wall 122d of seal 122.

Thus, notches 123 and 124 permit blades 118 and 120 to bend properly, as well as positioning blades 118 and 120 properly on top of seal 122, while still permitting blades 118 and 120 to seal at inner facing side wall surface 111 of side wall 122d of seal 122. As a result of this construction, blades 118 and 120 are permitted to bend at the position of seal 122 while still providing a good sealing capability thereat.

It will be appreciated that the present invention is not limited to the above embodiment, but rather, is limited only by the claims herein. For example, upper concave surface portion 122a2 and intermediate upper wall portion 122a3, along with notch 124, can be eliminated so that there would be only upper concave surface portion 122a1 and single notch 123 at each end of each blade 118 and 120.

As a further embodiment, notches 123 and 124, and blade engaging extensions 122i and 112j, can be eliminated entirely. In other words, it is only important that an edge of the blade 118 and 120 seal against inner facing side wall surface 111 of seal 122. For example, as an alternative embodiment of a seal 122′, shown in FIG. 1A, blade engaging extensions 122i and 122j are connected together in a large extension 122k which also covers and eliminates downwardly sloping flat upper blade supporting surfaces 122b and 122c of FIG. 1. In other words, there are no downwardly sloping flat upper blade supporting surfaces 122b and 122c on which the blade rests. Large extension 122k also extends the surface area of inner facing side wall surface 111. In this regard, a conventional blade, which is held separately by a blade holder, is positioned so that the end edges thereof (edge 131 in FIGS. 10 and 11) seal against inner facing side wall surface 111. The alignment of the end edges of the blade against inner facing side wall surface 111 can be performed manually or with detection equipment, such as an optical detector of the like.

It will be appreciated that the first embodiment of seal 122 of FIG. 1 has the advantage over the seal 122′ of FIG. 1A of also automatically accurately aligning side edges 130a of blades 118 and 120 in sealing contact with inner facing side wall surface 111, as a result of notches 123 and 124 and blade engaging extensions 122i and 112j.

In accordance with a second aspect of the present invention, as shown best in FIGS. 4 and 7, and as discussed above, seal 122 is made from an elastomer which is deformable and resilient. The elastomer forming seal 122 has an internal lubricant chamber 113 filled with a lubricant 115. When, due to wear, the pressure on a portion of seal 122 which lies against the peripheral surface of anilox roll 112 increases, an opening 134, or a plurality of such openings, in that intermediate upper wall portion 122a3 of upper surface 122a between upper concave surface portions 122a1 and 122a2 at the inlet end, allows lubricant 115 to flow from internal lubricant chamber 113 to the interface between seal 122 and anilox roll 112. Increased pressure on seal 122 against the peripheral surface of anilox roll 112 increases the pressure of the lubricant in lubricant chamber 113 and causes the lubricant to flow from lubricant chamber 113 to the interface between seal 122 and anilox roll 112.

As a result, lubricant 115 in internal lubricant chamber 113 of seal 122 is caused to flow to the anilox roll/seal interface upon increased pressure of seal 122 on anilox roll 112, which reduces the wear on seal 122, and particularly, on upper concave surface portions 122a1 and 122a2.

It will be appreciated that, although the present invention has been discussed in relation to an anilox roll, the present invention is not limited thereby, and is applicable to any fluid carrying roll, such as a gravure roll, an ink roll, etc. Further, the present invention is not limited to rolls associated with a printing operation and can be used with other fluid carrying rolls-associated with other operations where a doctoring/sealing operation is required, such as glue rolls, etc.

Having described a specific preferred embodiment of the invention with reference to the accompanying drawings, it will be appreciated that the present invention is not limited to that precise embodiment and that various changes and modifications can be effected therein by one of ordinary skill in the art without departing from the scope or spirit of the invention as defined by the appended claims.

Claims

1. A sealing assembly for a fluid chamber which supplies fluid to a roll, comprising: a first seal adapted to seal an end of the fluid chamber, said first seal including: a first upper wall including a first upper concave surface adapted to engage an outer surface of the roll, anda first inner facing side wall surface;a second seal adapted to seal an opposite end of the fluid chamber, said second seal including: a second upper wall including a second upper concave surface adapted to engage the outer surface of the roll, anda second inner facing side wall surface; anda doctor blade having a doctoring edge for doctoring fluid on the roll, and opposite first and second end edges, said first end edge being in sealing engagement with said first inner facing side wall surface and said second end edge being in sealing engagement with said second inner facing side wall surface.

2. A sealing assembly according to claim 1, wherein: the doctor blade includes first and second opposite ends;the first seal includes: a first flat upper doctor blade supporting surface at one end of the first upper wall for receiving the first end of the doctor blade thereon, anda first doctor blade engaging extension positioned above said first flat upper supporting surface;the second seal includes: a second flat upper doctor blade supporting surface at one end of the second upper wall for receiving the second end of the doctor blade thereon, anda second doctor blade engaging extension positioned above said second flat upper supporting surface;the first end of the doctor blade having a first cut-out notch therein at said doctoring edge for engaging with said first doctor blade engaging extension to accurately align said first end of the doctor blade with said first seal, said first cut-out notch having a first side edge forming the first end edge in sealing engagement with the first inner facing side wall surface; andthe second end of the doctor blade having a second cut-out notch therein at said doctoring edge for engaging with said second doctor blade engaging extension to accurately align said second end with said second seal, said second cut-out notch having a second side edge forming the second end edge in sealing engagement with the second inner facing side wall surface.

3. A sealing assembly according to claim 2, wherein each doctor blade engaging extension is formed as a continuation of a respective said upper wall.

4. A sealing assembly according to claim 2, wherein each of said first and second upper concave surfaces is formed by first and second spaced apart upper concave surface portions.

5. A sealing assembly according to claim 4, wherein: said first seal includes a third doctor blade engaging extension positioned above said first flat upper doctor blade supporting surface in spaced relation from said first doctor blade engaging extension;said second seal includes a fourth doctor blade engaging extension positioned above said second flat upper doctor blade supporting surface in spaced relation from said second doctor blade engaging extension;the first end of the doctor blade includes two said first cut-out notches therein at said doctoring edge for engagement with said first and third doctor blade engaging extensions, and a tab between said two first cut-out notches for engagement with said first flat upper doctor blade supporting surface; andthe second end of the doctor blade includes two said second cut-out notches therein at said doctoring edge for engagement with said second and fourth doctor blade engaging extensions, and a tab between said two second cut-out notches for engagement with said second flat upper doctor blade supporting surface.

6. A sealing assembly according to claim 1, further comprising a sealing blade having a sealing edge for sealing fluid on an opposite side of the fluid chamber, and opposite first and second end edges, said first end edge of the sealing blade being in sealing engagement with said first inner facing side wall surface and said second end edge of the sealing blade being in sealing engagement with said second inner facing side wall surface.

7. A sealing assembly according to claim 6, wherein: the sealing blade includes opposite first and second ends;the first seal includes: a first flat upper sealing blade supporting surface at an opposite end of the first upper wall for receiving the first end of the sealing blade thereon, anda first sealing blade engaging extension positioned above said first flat upper sealing blade supporting surface;the second seal includes: a second flat upper sealing blade supporting surface at an opposite end of the second upper wall for receiving the second end of the sealing blade thereon, anda second sealing blade engaging extension positioned above said second flat upper sealing blade supporting surface;the first end of the sealing blade having a first cut-out notch therein for engaging with said first sealing blade engaging extension to accurately align said first end of the sealing blade with said first seal, said first cut-out notch of the sealing blade having a first side edge forming the first end edge of the sealing blade in sealing engagement with the first inner facing side wall surface;the second end of the sealing blade having a second cut-out notch therein for engaging with said second sealing blade engaging extension to accurately align said second end of the sealing blade with said second seal, said second cut-out notch having a second side edge forming the second end edge of the sealing blade in sealing engagement with the second inner facing side wall surface.

8. A sealing assembly according to claim 7, wherein each extension is formed as a continuation of a respective said upper concave surface.

9. A sealing assembly according to claim 7, wherein each of said first and second upper concave surfaces is formed by first and second spaced apart upper concave surface portions.

10. A sealing assembly according to claim 9, wherein: said first seal includes a third sealing blade engaging extension positioned above said first flat upper supporting surface in spaced relation from said first sealing blade engaging extension;said second seal includes a fourth sealing blade engaging extension positioned above said second flat upper supporting surface in spaced relation from said second sealing blade engaging extension;the first end of the sealing blade includes two said first cut-out notches therein at said sealing edge for engagement with said first and third sealing blade engaging extensions, and a tab between said two first cut-out notches for engagement with said first flat upper sealing blade supporting surface; andthe second end of the sealing blade includes two said second cut-out notches therein at said sealing edge for engagement with said second and fourth sealing blade engaging extensions, and a tab between said two second cut-out notches for engagement with said second flat upper sealing blade supporting surface.

11. A sealing assembly according to claim 1, wherein each of said first and second upper concave surfaces is formed by first and second spaced apart upper concave surface portions.

12. A method of sealing a fluid chamber which supplies fluid to a roll, comprising the steps of: positioning a first seal of a type having a first upper wall including a first upper concave surface adapted to engage an outer surface of the roll, and a first inner facing side wall surface, at an end of the fluid chamber to seal said end of the fluid chamber,positioning a second seal of a type having a second upper wall including a second upper concave surface adapted to engage the outer surface of the roll, and a second inner facing side wall surface, at an opposite end of the fluid chamber to seal said opposite end of the fluid chamber, andpositioning a doctor blade having a doctoring edge for doctoring fluid on the roll against the roll such that a first end edge thereof is in sealing engagement with said first inner facing side wall surface and an opposite second end edge thereof is in sealing engagement with said second inner facing side wall surface.

13. A method according to claim 12, wherein: the doctor blade includes first and second opposite ends;the first seal includes: a first flat upper doctor blade supporting surface at one end of the first upper wall for receiving the first end of the doctor blade thereon, anda first doctor blade engaging extension positioned above said first flat upper doctor blade supporting surface;the second seal includes: a second flat upper doctor blade supporting surface at one end of the second upper wall for receiving the second end of the doctor blade thereon, anda second doctor blade engaging extension positioned above said second flat upper doctor blade supporting surface;the first end of the doctor blade having a first cut-out notch therein at said doctoring edge; andthe second end of the doctor blade having a second cut-out notch therein at said doctoring edge; andfurther comprising the steps of: engaging the first cut-out notch with said first doctor blade engaging extension to accurately align said first end of the doctor blade with said first seal such that a first side edge of said first cut-out notch which forms the first end edge is in sealing engagement with the first inner facing side wall surface; andengaging the second cut-out notch with said second doctor blade engaging extension to accurately align said second end of the doctor blade with said second seal such that a second side edge of said second cut-out notch which forms the second end edge is in sealing engagement with the second inner facing side wall surface.

14. A method according to claim 12, further comprising the step of positioning a sealing blade having a sealing edge for sealing fluid on an opposite side of the fluid chamber against the roll such that a first end edge thereof is in sealing engagement with said first inner facing side wall surface and an opposite second end edge thereof is in sealing engagement with said second inner facing side wall surface.

15. A method according to claim 14, wherein: the sealing blade includes opposite first and second ends;the first seal includes: a third flat upper sealing blade supporting surface at an opposite end of the first upper wall for receiving the first end of the sealing blade thereon, anda third sealing blade engaging extension positioned above said third flat upper sealing blade supporting surface;the second seal includes: a fourth flat upper sealing blade supporting surface at an opposite end of the second upper wall for receiving the second end of the sealing blade thereon, anda fourth sealing blade engaging extension positioned above said fourth flat upper sealing blade supporting surface;the first end of the sealing blade having a first cut-out notch therein at said sealing edge;the second end of the sealing blade having a second cut-out notch therein at said sealing edge; andfurther comprising the steps of: engaging the first cut-out notch of the sealing blade with said third sealing blade engaging extension to accurately align said first end of the sealing blade with said first seal such that a first side edge of said first cut-out notch of said sealing blade is in sealing engagement with the first inner facing side wall surface;engaging the second cut-out notch of the sealing blade with said fourth sealing blade engaging extension to accurately align said second end of the sealing blade with said second seal such that a second side edge of said second cut-out notch of the sealing blade is in sealing engagement with the second inner facing side wall surface.

16. A seal adapted to seal an end of a fluid chamber which supplies fluid to a roll, comprising: at least one supporting wall,an upper wall including an upper concave surface on said at least one supporting wall and adapted to engage an outer surface of the roll,a flat upper doctor blade supporting surface at one end of the upper wall for receiving an end of a doctor blade thereon,an inner facing side wall surface, anda doctor blade engaging extension positioned above said flat upper doctor blade engaging supporting surface and adapted to engage within a notch at an end of the doctor blade to permit the doctor blade to bend thereat such that an end edge of the doctor blade at the notch slides along the inner facing side wall surface to maintain a sealing arrangement between the doctor blade and said seal when the doctor blade bends at said notch.

17. A seal according to claim 16, wherein said seal further includes: a second flat upper sealing blade supporting surface at an opposite end of the upper wall for receiving an end of a sealing blade thereon, anda second sealing blade engaging extension positioned above said second flat upper sealing blade supporting surface for engaging within a notch at the end of said sealing blade to permit said sealing blade to bend thereat such that an end edge of the sealing blade at the notch slides along the inner facing side wall surface to maintain a sealing arrangement between the sealing blade and said seal when the sealing blade bends at said notch.

18. A seal according to claim 17, wherein each said sealing blade engaging extension is formed as a continuation of said upper wall.

19. A seal according to claim 16, wherein said upper concave surface includes first and second spaced apart upper concave surface portions.

20. A seal adapted to seal an end of a fluid chamber which supplies fluid to a roll, comprising: at least one supporting wall,an upper wall on said at least one supporting wall, said upper wall including an upper concave surface adapted to engage an outer surface of the roll,opposite end walls,a lubricant chamber defined between said at least one supporting wall, said upper wall and said ends walls, for holding a lubricant therein,said seal being made of a deformable and resilient material, andwherein said upper wall includes at least one opening through which said lubricant is forced out of said lubricant chamber when said seal is deformed as a result of external pressure thereon.

21. A seal according to claim 20, wherein each end wall includes a flat upper blade supporting surface for receiving an end of a blade thereon.

22. A seal according to claim 20, wherein said upper concave surface includes first and second spaced apart upper concave surface portions with an intermediate upper wall portion therebetween.

23. A seal according to claim 22, wherein said at least one opening is formed through said intermediate upper wall portion.

24. A seal according to claim 20, wherein said at least one supporting wall includes an inner facing side wall surface, and said seal includes a doctor blade engaging extension positioned above each said end wall and adapted to engage within a first cut-out notch at the end of a doctor blade to permit the doctor blade to bend thereat such that a side edge of the first cut-out notch in is in sealing engagement with the inner facing side wall surface.

25. A seal according to claim 24, wherein said seal further includes a sealing blade engaging extension positioned above said second end wall for engaging within a second cut-out notch at an opposite end of a sealing blade to permit the sealing blade to bend thereat such that a side edge of the second cut-out notch is in sealing engagement with the inner facing side wall surface.

26. A seal according to claim 25, wherein each sealing blade engaging extension is formed as a continuation of said upper concave surface.

27. A doctor/sealing blade for use with seals adapted to doctor/seal ends of a fluid chamber which supplies fluid to a roll, with the seals being of a type including at least one supporting wall having an inner facing side wall surface, an upper wall including an upper concave surface on the at least one supporting wall and adapted to engage an outer surface of the roll, a flat upper blade supporting surface at one end of the upper wall, and a blade engaging extension positioned above each said flat upper blade supporting surface, the doctor/sealing blade comprising: a thin plate having a lengthwise edge and opposite first and second ends, each end adapted to seat on the flat upper blade supporting surface of each respective seal, andat least one cut-out notch at each end of said thin plate at said lengthwise edge and adapted to receive a blade engaging extension of one said seal therein to permit the blade to bend thereat such that a side edge of said at least one cut-out notch is in sealing engagement with the inner facing side wall surface.

28. A doctor blade according to claim 26, wherein each end of the blade includes two said spaced apart cut-out notches therein at said lengthwise edge and a tab between said cut-out notches.