Patent Grant
8474378
The present invention relates to a sealing assembly for an ink chamber associated with an anilox roll and chamber blade assembly, and more particularly, is directed to an improved doctor/containment blade with an improved blade/seal area between the doctor blade and containment blade and the chamber seal.
Conventionally, in printing machines, such as flexographic printing machines, an ink transfer or anilox roll transfers ink to an adjacent plate roll for printing. Ink is supplied to the anilox roll from an ink chamber defined by a chamber housing which partially surrounds the anilox roll. Specifically, ink is supplied through an ink supply tube and then through an ink supply line in the chamber housing, into the ink chamber. In like manner, ink is removed from the ink chamber through an ink return line in the chamber housing and then through an ink return tube.
In order to prevent the escape of ink from the chamber, while ensuring that the ink enters the cells in the anilox roll and has a predetermined volume on the anilox roll, doctor and containment blades are provided at the exit and entry positions of the anilox roll relative to the ink chamber. The blades are fixed to the chamber housing so that the blades overhang the chamber housing and contact the anilox roll.
With this arrangement, the outer surface of the anilox roll passes through the ink chamber and picks up ink for printing. The ink is metered by means of the doctor blade held to the outlet end of the chamber housing, and sealed with a containment blade held to the inlet end, with the free ends of the blades being in contact with the outer surface of the anilox roll.
A seal is provided at each end of the blade, that is, at each end of an anilox roll for sealing the ends thereof. Examples of such arrangements are shown in U.S. Pat. Nos. 6,739,248; 6,672,207; 6,598,525; 5,983,797; 5,735,210; 5,662,042; and 5,150,651.
Examples of doctor blades used in such arrangement are shown in U.S. Pat. Nos. 5,638,751 and 6,546,861.
Each seal is formed by a compressible or deformable body. Since the seals provided at each end of the anilox roll function to seal the ends of the ink chamber, each seal must lie against the peripheral surface of the rotating anilox roller. As a result, each seal is therefore exposed to mechanical stresses as well as wear. Further, during the printing operation, the blades, which press against the anilox roll, also wear. The geometry of the sealing function between the anilox roll, the two blades and the end seal changes.
Conventionally, each end of a blade sits upon a flat supporting area of the respective seal. As a result, a gap may be created at the opposite ends of the blades where they are held by the chamber seals. However, there is uneven wear on the ends of the blades adjacent the seals, which tends to cause leakage of ink at the ends of the anilox roll. As the doctor blades are forced against the anilox roll and, in particular, when the doctor blades wear unevenly in the sealing area, the sealing and doctor blades may flex or bow outwardly relative to the flat supporting area of the seal, due in part to the flimsiness of the thin blades, pressure on the blades, dried ink under the blades, fluid pressure in the chamber, etc. Thus, the areas where the anilox roll, blades and seals join are susceptible to leakage because of geometric changes.
The above U.S. patent application Ser. No. 12/710,763 provides a solution to the above problems by providing an improved doctor blade and containment blade with additional wear resistance, improved leakage resistance, increased rigidity and increased wear life at the position of the end seals. This is accomplished by a wear element which increases the stiffness and/or wear of the thin plate of the blades, the wear element mounted to a surface of the thin plate at least at a position corresponding to the end seals, such that the thickness of the reinforced blade is greater at the opposite ends thereof which lie against the seals than at positions thereof between the end seals.
However, the wear element increases the thickness of the blade thereat. Because of the extra thickness thereat, when the wear element hits the anilox roll, there is increased force by the anilox roll on the blade at this position, which can result in undesirable effects. Specifically, because of this increased force on the blade, the blade wears faster thereat, even though the life of the blade at this position is still longer than a blade without the wear element. There are also wiping problems thereat which can cause dripping of the ink.
Accordingly, it is an object of the present invention to provide an improved containment blade with an improved sealing function with the seals associated therewith at the ends of the ink chamber.
It is another object of the present invention to provide an improved containment blade with additional wear resistance at the position of the end seals.
It is a still further object of the present invention to provide an improved containment blade that provides improved leakage resistance at the end seals.
It is a yet further object of the present invention to provide an improved containment blade that provides increased wear life thereof.
It is another object of the present invention to provide an improved containment blade having increased rigidity at the end seals.
It is still another object of the present invention to provide an improved containment blade that eliminates the aforementioned wiping problems.
It is yet another object of the present invention to provide an improved containment blade that is easy to use and economical to manufacture.
In accordance with an aspect of the present invention, a chamber blade/sealing assembly for use with a fluid chamber which supplies fluid to a roll, includes a containment blade including an elongated thin plate having opposite ends; and a wear element which increases at least one of stiffness and wear of the thin plate, the wear element mounted to a surface of the thin plate at the opposite ends thereof. First and second end seals for sealing first and second ends of the fluid chamber are provided. Each of the first and second end seals include at least one supporting wall, an upper concave surface on the at least one supporting wall and adapted to engage an outer surface of the roll, and a first upper supporting surface extending from one end of the upper concave surface, the first upper supporting surface adapted to receive the wear element such that the wear element does not substantially increase pressure from the roll on the containment blade at the first upper supporting surface.
In one embodiment, the first upper supporting surface includes a recess therein, and the wear element is positioned within the recess. The recess can be bounded by a raised wall at at least one end thereof. Preferably, the wear element has a shape and dimensions similar to those of the recess.
Preferably, the wear element is a plate material made from the same material as the blade, and has a thickness at least equal to a thickness of the blade.
The first upper supporting surfaces are formed by downwardly sloping flat supporting surfaces which continue at an angle from one edge of the upper concave surface.
In addition, a height of each first upper supporting surface at any point thereon is lower than would be required for a chamber blade/sealing assembly without said wear element, in order to account for extra thickness of the containment blade and wear element together.
The end seal is made of one of a compressible and deformable material, and the compressible and deformable material of a portion of said seal containing the first upper supporting surface has a durometer which is less than a durometer of the compressible and deformable material of a remainder of said seal.
In accordance with another aspect of the present invention, a chamber blade/sealing assembly for use with a fluid chamber which supplies fluid to a roll, includes a containment blade including an elongated thin plate having opposite ends; and a wear element which increases at least one of stiffness and wear of the thin plate, the wear element mounted to a surface of the thin plate at the opposite ends thereof. First and second end seals for sealing first and second ends of the fluid chamber are provided. Each of the first and second end seals include at least one supporting wall, an upper concave surface on the at least one supporting wall and adapted to engage an outer surface of the roll, and a first upper supporting surface extending from one end of the upper concave surface, the first upper supporting surface adapted to receive the wear element such that an effective thickness of the containment blade and the wear element together between the seal and the roll remains substantially the same as the thickness of the containment blade alone.
The above and other objects, features and advantages of the invention will become readily apparent from the following detailed description thereof which is to be read in connection with the accompanying drawings.
Referring to the drawings in detail, and initially to
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, an elongated sealing or containment blade 18 and an elongated doctor blade 20 are provided at the entry and exit positions of anilox roll 12 relative to ink chamber 14. Blades 18 and 20 each include a clamping portion that is fixed to chamber housing 16 by a blade holder (not shown) at a position beyond the chamber housing 16, as is well known in the art, 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 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 containment blade 18 held to the inlet end, with the roll contact portions, that is, the free contact edges, of blades 18 and 20 being in contact with the outer surface of anilox roll 12.
However, each end of blades 18 and 20 sits upon a supporting surface 22b or 22c of a respective seal 22. As a result, in part because of the flimsiness or thinness of the blades, a gap may be created at the opposite ends of the blades 18 and 20 where they are in contact with the chamber seal 22. Because there is uneven wear of blades 18 and 20 adjacent seals 22, this tends to cause leakage of ink at the ends of anilox roll 12. In such case, the sealing and doctor blades 18 and 20 may flex or bow outwardly relative to the supporting surfaces 22b and 22c of the respective seal 22, as shown in
In addition, another problem at the end seals is that of back blading. Specifically, as anilox roll 12 rotates, each position thereon reenters the ink chamber 16. During this rotation when containment blade 18 is the upper blade, ink thereat catches on containment blade 18 and builds up at this position. The ink then builds up and runs along the interface of containment blade 18 and anilox roll 12, and drips down from the edge of containment blade 18 in the seal area. When containment blade 18 is the lower blade, the ink merely drips down and creates stalactites of ink.
As a result, in order to prevent or limit back blading, it is known to increase the width of containment blade 18, for example, from 25 mm to 35 mm, with the extra width section 18a thereof being bent such that the portion of containment blade 18 in contact with anilox roll 12 is at an acute angle α which is much less than the angle β of contact of a conventional 25 mm blade, as shown in
Referring now to
The width of each wear element 21 preferably extends to the outer edge of the respective flat supporting surface 22b and 22c, but is not limited thereto, and may vary in width therefrom. Each wear element 21 can be of any suitable thickness. Wear element 21 can be made of any suitable material, such as the same material as blades 18, 20.
With wear elements 21 added to each blade 18, 20, the rigidity of each blade 18,20 at downwardly sloping flat supporting surfaces 22b and 22c of seal 22, is increased. As a result, there is much less tendency for each blade 18, to bow at the position of seals 22. In effect, each wear element 21 inhibits or prevents ink from entering into the area between blades 18, 20 and downwardly sloping flat supporting surfaces 22b and 22c of seals 22, thereby inhibiting or preventing leakage of ink at the seal areas.
It is noted that, at each seal area, the respective blade 18, 20 may wear down faster than at areas between the seal areas where the blades 18, 20 are in contact with anilox roll 12, since there is little or no lubricating ink at the seal areas. As a result, an opening may develop in each blade 18, 20 at the seal areas through which ink can leak, particularly if the blades 18, 20 are bowed outwardly. This ink leakage under the blades 18, 20 tends to push the respective blades 18, 20 further away from downwardly sloping flat supporting surfaces 22b and 22c of seal 22, which results in further leakage of ink thereat. By providing the extra material thickness of wear elements 21, even if a wear opening is provided in each blade 18, 20, the blade is not pushed away from downwardly sloping flat supporting surfaces 22b and 22c of seal 22, due to the increased rigidity of the blades 18, 20 at the seal areas, so that there is little or no ink leakage. Further, as the blade wears down in the seal area, the anilox roll 12 comes into contact with the increased thickness wear element 21, whereby the additional material of wear element 21 functions to increase the wear life of the blade.
It will be appreciated that, while wear element 21 is preferably secured to blades 18, 20, it may be provided as a separate element held by the machine and which lies against the same area of blades 18, 20 described herein. Therefore, reference to wear element 21 being “mounted” refers to wear element 21 being fixed to blades 18, 20, or as a separate element pressed thereagainst.
Further, as shown in
In such case, extra width portion 18a is also positioned between anilox roll 12 and seal 22, as shown in
However, by additionally providing wear element 21, leakage does not occur, even with such open area 19. As a result, in tests performed by the applicant herein, a containment blade 18 with an extra width portion 18a but without wear elements 21, leaked in a flexographic printing machine in about 12 hours. However, the same blade 18 in the same flexographic printing machine and under the same conditions, but with wear elements 21 added of the same material and thickness as blade 18, was still functioning with little or no ink leakage even after 24 hours of operation, even though a similar open area 19 was created. Because wear element 21 is in contact with anilox roll 12, the wear life of blade 18 is greatly increased.
Thus, the invention of U.S. patent application Ser. No. 12/710,763, provides that the material of blade 18 is sufficiently flexible to bend and pass between anilox roll 12 and seal 22, while made sufficiently rigid by wear element 21 to prevent leakage beneath blade 18, even when worn away to provide an open area 19 thereof.
Although wear element 21 has been shown mounted on the outer surface of each blade 18, 20 outside of the ink chamber, it can be mounted on the inner surface within the ink chamber.
The invention of the above U.S. patent application Ser. No. 12/710,763 thereby provides an improved doctor blade and containment blade with additional wear resistance, improved leakage resistance, increased rigidity and increased wear life at the position of the end seals. This is accomplished by a wear element which increases the stiffness and/or wear of the thin plate of the blades, the wear element mounted to a surface of the thin plate at least at a position corresponding to the end seals, such that the thickness of the reinforced blade is greater at the opposite ends thereof which lie against the seals than at positions thereof between the end seals.
However, wear element 21 increases the thickness of the blade thereat. Because of the extra thickness thereat, when wear element 21 hits the anilox roll, there is increased force by the anilox roll on the blade at this position, which can result in undesirable effects. Specifically, because of this increased force on the blade, the blade wears faster thereat, even though the life of the blade at this position is still longer than a blade without wear element 21. There are also wiping problems thereat which can cause dripping of the ink.
Referring now to
It will be appreciated that the present invention is also applicable to the modification of
It will be appreciated that, instead of a recess 22d which is bounded at opposite ends thereof by raised walls, as shown in
As a further alternative, in place or recess 22d or lower height downwardly sloping supporting surface 22b, the height of downwardly sloping supporting surface 22b can be the same as that of a downwardly sloping supporting surface 22c which would be required for a chamber blade/sealing assembly without wear element 21. However, at least a portion 22e of seal 22 shown by dashed lines in
It will be appreciated that combinations of the above embodiments can be provided. For example, the recess 22d or lowered height downwardly sloping supporting surface 22b need not have a height corresponding to the thickness of wear element 21, but can have a height less than the thickness of wear element 21. In such case, recess 22d or lowered height downwardly sloping supporting surface 22b can be combined with a lower durometer material thereat to provide the same result.
The key to all of the above embodiments is that wear element 21 increases the life of containment blade 18, while not increasing the pressure or force thereon at the position of end seal 22.
In this regard, it will be appreciated that containment blade 18, rather than wear element 21, can be in direct contact with downwardly sloping supporting surface 22b or recess 22d, as long as the effective thickness of containment blade 18 and wear element 21 between seal 22 and roll 12 remains substantially the same as the thickness of containment blade 18 alone.
Having described specific preferred embodiments of the invention with reference to the accompanying drawings, it will be appreciated that the present invention is not limited to those precise embodiments 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.
The present application is a continuation-in-part of pending U.S. patent application Ser. No. 12/710,763, filed Feb. 23, 2010 and having one of the inventors thereof as the common inventor herein and entitled IMPROVED DOCTOR/CONTAINMENT BLADE FOR A PRINTING PRESS.
| Number | Name | Date | Kind |
|---|---|---|---|
| 273536 | Howell, Jr. | Mar 1883 | A |
| 805100 | Silver | Nov 1905 | A |
| 1092798 | Nuttall | Apr 1914 | A |
| 2148456 | Grossarth | Feb 1939 | A |
| 2313830 | Lundbye | Mar 1943 | A |
| 2361554 | Lundbye | Oct 1944 | A |
| 2495017 | Meyer | Jan 1950 | A |
| 3273536 | Galer et al. | Sep 1966 | A |
| 3848992 | Smith | Nov 1974 | A |
| 3848993 | Hasiotis | Nov 1974 | A |
| 3855927 | Simeth | Dec 1974 | A |
| 4060031 | Philipp | Nov 1977 | A |
| 4089264 | Jeschke et al. | May 1978 | A |
| 4184429 | Widmer | Jan 1980 | A |
| 4254709 | Arnolds | Mar 1981 | A |
| 4373445 | Kobler | Feb 1983 | A |
| 4378736 | Sarda | Apr 1983 | A |
| 4393775 | Cappel et al. | Jul 1983 | A |
| 4538518 | Dahlgren | Sep 1985 | A |
| 4676160 | Linska | Jun 1987 | A |
| 4773327 | Moetteli | Sep 1988 | A |
| 4821672 | Bruno | Apr 1989 | A |
| 5027513 | Allison, Jr. | Jul 1991 | A |
| 5046414 | Oozeki | Sep 1991 | A |
| 5119755 | Beisswanger | Jun 1992 | A |
| 5150651 | Flores | Sep 1992 | A |
| 5152221 | Weeks | Oct 1992 | A |
| 5237375 | Michlin et al. | Aug 1993 | A |
| 5410961 | DeNicola et al. | May 1995 | A |
| 5483885 | Leineweber | Jan 1996 | A |
| 5524540 | Van Denend | Jun 1996 | A |
| 5536312 | Madrzak et al. | Jul 1996 | A |
| 5638751 | Daetwyler et al. | Jun 1997 | A |
| 5662042 | Compton et al. | Sep 1997 | A |
| 5713276 | Teoh et al. | Feb 1998 | A |
| 5735210 | Rogge et al. | Apr 1998 | A |
| 5806427 | Niemiro et al. | Sep 1998 | A |
| 5826296 | Steven | Oct 1998 | A |
| 5895150 | Watabe et al. | Apr 1999 | A |
| 5983797 | Secor | Nov 1999 | A |
| 5983798 | Iijima et al. | Nov 1999 | A |
| 6016748 | Kolbe | Jan 2000 | A |
| 6112661 | Albiez | Sep 2000 | A |
| 6202252 | Harrisson | Mar 2001 | B1 |
| 6318259 | Chou et al. | Nov 2001 | B1 |
| 6360660 | Allison, Jr. | Mar 2002 | B1 |
| 6405649 | Fina | Jun 2002 | B1 |
| 6412410 | Poullier | Jul 2002 | B1 |
| 6526884 | Bardet et al. | Mar 2003 | B1 |
| 6546861 | Manser | Apr 2003 | B2 |
| 6571703 | Metrope | Jun 2003 | B1 |
| 6598525 | Metrope | Jul 2003 | B2 |
| 6629496 | Boose et al. | Oct 2003 | B1 |
| 6672207 | Kolbe et al. | Jan 2004 | B2 |
| 6739248 | Kolbe et al. | May 2004 | B2 |
| 6799509 | Naniwa | Oct 2004 | B2 |
| 7597761 | Van Denend | Oct 2009 | B2 |
| 20030121435 | Jendroska et al. | Jul 2003 | A1 |
| 20040261640 | Maccagni et al. | Dec 2004 | A1 |
| Number | Date | Country |
|---|---|---|
| 847173 | Sep 1960 | GB |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12710763 | Feb 2010 | US |
| Child | 13026791 | US |
