WO2005108086A1

WO2005108086A1 - A brush arrangement for a blanket cylinder

Info

Publication number: WO2005108086A1
Application number: PCT/SE2005/000524
Authority: WO
Inventors: Birger Hansson
Original assignee: Baldwin Jimek Ab
Priority date: 2004-05-07
Filing date: 2005-04-13
Publication date: 2005-11-17
Also published as: EP1742799A1; SE0401186D0; EP1742799B1; SE526314C2; SE0401186L

Abstract

A brush arrangement (4; 26) for cleaning a blanket (7) on a rotatable blanket cylinder (3) in a printing press (1) from printing ink, paper fibers, lint and the like, includes a pivoting arrangement (8) for its application against the blanket cylinder (3). The brush arrangement (4; 26) includes at least one row of bristles (23a; 23b) that are inclined in relation to an axis perpendicular to the longitudinal direction of the brush arrangement (4; 26).

Description

A BRUSH ARRANGEMENT FOR A BLANKET CYLINDER

TECHNICAL FIELD The present invention relates to a brush arrangement for cleaning a blanket on a rotatable blanket cylinder in a printing press from printing ink, paper fibers, lint, and the like.

BACKGROUND OF THE INVENTION As is well known in the printing industry, one cylinder in an offset printing press is a blanket cylinder, provided on its surface with a so-called blanket, normally made of rubber. The blanket that is attached to the blanket cylinder needs to be cleaned at intervals to remove printing ink, paper fibers, lint, and the like that sticks to the blanket during the printing process. It is previously known to have a brush arrangement that is axially applied to the blanket and where the brush arrangement is oscillated on the surface of the blanket during the rotation of the blanket cylinder. A separate dampening device supplies cleaning liquid. The dampening device may also be provided on the brush arrangement. An example of an oscillating brush arrangement is shown in US-Bl-6 557 470. The oscillation of the brush arrangement provides a fairly good cleaning process of the blanket, but the axial application to and removing of the brush arrangement from the blanket often cause an undesired pattern on the blanket. It is also previously known from US-Bl-4 972 780 to have a brush arrangement that is pivoted between an engaged and a disengaged position, which reduces the occurrence of undesired patterns on the blanket during the removing action, but there is still a problem with remaining patterns on the blanket. The problem with the solution according to the prior art is that a pattern of the cleaning brush arrangement remains on the blanket, no matter if the brush arrangement is axially or pivotally removed from the blanket. Another problem is that the result of the cleaning with prior art cleaning solutions not is satisfying.

SUMMARY OF THE INVENTION These problems may according to the invention be solved by a pivoting application of a brush arrangement to the blanket together with at least one row of inclined bristles arranged on the brush arrangement. There may be two parallel rows of bristles, arranged with the opposite inclination of the rows. The rows of bristles may be replaceably arranged in two grooves. Further aspects of the invention are covered by the dependent claims .

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in further detail below with reference to the accompanying drawings, in which: Fig. 1 shows an overview of a printing press with brush arrangements according to the present invention; Fig. 2 shows an enlargement of area A in Fig. 1; Figs. 3a-3b show perspective views of a certain portion of the brush arrangement according to the present invention in two working positions; Fig. 4a shows a perspective view of the brush arrangement according to the present invention; Fig. 4b shows an enlargement of area B in Fig. 4a; Figs. 5a-5b show side views of a first embodiment of the brush arrangement according to the present invention in two working positions; Figs. βa-6b show side views of a second embodiment of the brush arrangement according to the present invention in two working positions; and Fig. 7 shows a perspective view of the brush arrangement according to the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS In Fig. 1 an overview of a printing press 1, more particularly an offset printing press, is shown with supply arrangements 2, blanket cylinders 3, brush arrangements 4, an applicator 5 and a paper web 6. Each supply arrangement 2 includes an ink tray with the printing ink, a dampening device/spray bar for fountain solution, a printing cylinder with printing plates, an ink train transferring ink from the ink tray to the printing cylinder and a fountain solution train transferring fountain solution to the printing cylinder. The ink contained in the ink tray is transferred to the printing cylinder and to the printing areas thereof by the ink train. The fountain solution contained in the dampening device is sprayed to a first cylinder of the fountain solution train and further transferred by other cylinders in the fountain solution train to the printing cylinder and to the non-printing areas thereof. The print of the printing cylinder is transferred to the paper web 6 via the blanket cylinder 3. The basic function of the offset press is that the paper web 6 is fed through the printing press 1 getting in contact with a blanket 7 mounted on each blanket cylinder, where the ink in the printing layout has been provided on the blanket 7 by the printing cylinder and is printed on the paper web 6. The brush arrangement 4, that is used after a printing process to clean the blanket 7 from residues from the printing process, e.g. printing ink, paper fibers, lint or the like, is provided at each blanket cylinder 3. In Fig. 2 the brush arrangement 4 has been applied to the blanket cylinder 3 for cleaning the blanket 7, but is retracted therefrom during the printing process. The brush arrangement 4 is arranged parallelly to the blanket cylinder 3 and includes a pivoting arrangement 8 (see Figs. 3a and 3b) for pivoting the brush arrangement 4 from a ^ήon-cleaning position to a cleaning position, i.e. pivoting the brush arrangement 4 into contact with the blanket 7. In Figs. 3a and 3b, one end of the brush arrangement 4 and the pivoting arrangement 8 is shown, where the brush arrangement 4 is suspended by the pivoting arrangement 8. The pivoting arrangement 8 includes a plate 9, a suspension device 10 connected to the plate 9, and a cylinder arrangement 11 mounted on the suspension device 10 for the pivoting of the brush arrangement 4. The suspension device 10 is connected to the plate 9 by two elongated, hexagonal parts 12 arranged between the suspension device 10 and the plate 9, and a set of bolts 13 holding the parts together,. Another set of bolts 14 connects the plate 9 to the superstructure of the printing press 1. In one end of the suspension device 10 a mounting bracket 15 is mounted by a set of bolts 16, and a first end of the cylinder arrangement 11 is attached to the mounting bracket 15. In the other end of the suspension device 10 the brush arrangement 4 is pivotally arranged in an aperture (not shown) . A stub axle 17 (see Fig. 4b) for suspending the brush arrangement 4 on the suspension device 10 is arranged in both ends of the brush arrangement 4 and projects through the aperture of the suspension device 10. The stub axle 17 is connected to a pivoting lever 18, which connects to a second end of the cylinder arrangement 11. The cylinder arrangement 11 is pivotally arranged in respect of the pivoting lever 18. The cylinder arrangement 11, which typically is connected to and controlled by a pneumatic system, comprises a piston 19 pivotally connected to the pivoting lever 18 and a cylinder 20 pivotally connected to the mounting bracket 15. By the pneumatic system the piston 19 can be pushed out of the cylinder 20 and be retracted into the cylinder 20, thereby pivoting the brush arrangement 4 connected to the piston 19. The cylinder arrangement 11 enables the brush arrangement 4 to be pivoted around an axis of the stub axle 17 from a first position to a second position. The first position is the non-cleaning position and the second position is the cleaning position. A retraction of the piston 19 pivots the brush arrangement 4 into the cleaning position and an extension of the piston 19 pivots the brush arrangement 4 into the non-cleaning position. In Fig. 3a the brush arrangement 4 is shown in the non-cleaning position, where the piston 19 of the cylinder arrangement 11 is extended. In Fig. 3b the brush arrangement 4 is shown in the cleaning position, where the piston 19 of the cylinder arrangement 11 is retracted into the cylinder 20. It should be appreciated that a similar pivoting arrangement 8 is arranged at the other end of the brush arrangement 4. It is, however, also possible to pivot the brush arrangement 4 by a single pivoting arrangement arranged at one of both ends of the brush arrangement 4. In Fig. 4a a first preferred embodiment of the brush arrangement 4 is shown with the pivoting arrangement 8 mounted at one end 21 of the brush _^arrangement 4. An enlargement of the other end 22 of the brush arrangement 4 is shown in Fig. 4b, where the stub axle 17 of the brush arrangement 4 is also shown. In Fig. 4b two rows of bristles 23a and 23b are also shown, where the bristles are inclined in relation to an axis perpendicular to the longitudinal direction C of the brush arrangement 4. The inclination of the bristles in the rows of bristles 23a, 23b is 10-45 degrees, preferably 20-30 degrees, in relation to the perpendicular axis A. If two rows of bristles are arranged in the brush arrangement, the two rows of bristles can be alternatively orientated, e.g. oppositely orientated. The distance between the two rows 23a, 23b is preferably approximately 15 mm, but can be varied as long as it is possible to pivotally remove the brush arrangement 4 without permanently damaging the brush arrangement 4 or the rows of bristles 23a, 23b, or without creating a pattern of the bristles on the blanket 7 after the bristles have been removed. In Fig. 4b a cover plate 24 is also shown, which is attached at the end 22 of the brush arrangement 4 by a bolt 25. The cover plate 24 covers the end of the brush arrangement 4, but also the ends of two longitudinal grooves wherein the rows of bristles 23a, 23b are removably arranged. The row of bristles 23a, 23b are arranged in profiles, which are preferably made of plastic and have holes therefore. The plastic profiles have a cross-section corresponding to the cross-section of the grooves to enable the profiles to be removably inserted in the grooves. The length of the plastic profiles typically equals the length of the grooves, but can also be shorter, so that several plastic profiles equal the length of the grooves. If several shorter profiles are arranged in the same row and the brush arrangement possibly includes only a single row of bristles, the profiles can be alternatively orientated so that the bristles are inclined in different directions along the profile, e.g. opposite directions. The bristles in the brush arrangement 4 are preferably made of nylon, but can be made of any suitable material that is able to withstand the chemical environment. The bristles preferably have a diameter of approximately 0.4 mm and a length of approximately 20 mm, but the dimensions can be varied within the scope of the invention as long as the contact pressure when applied against the blanket cylinder 3 is enough to clean the blanket 7 thoroughly. In Fig. 5a a side view of the brush arrangement 4 mounted on a pivoting arrangement 8 at one end of the brush arrangement 4 is shown, where the brush arrangement 4 is in the non-cleaning position. The piston 19 is extended. The two rows of bristles 23a, 23b are also shown. In Fig. 5b a side view of the brush arrangement 4 mounted on a pivoting arrangement 8 at one end of the brush arrangement 4 is shown, where the brush arrangement 4 is in the cleaning position. The piston 19 is retracted in the cylinder 20. In Fig. 6a a side view of an alternative brush arrangement 26 mounted on a pivoting arrangement 8 at one end of the brush arrangement 26 is shown, where the brush arrangement 26 is in the non-cleaning position. A piston 19 is extended. The brush arrangement 26 corresponds to the brush arrangement 4, but also includes a dampening arrangement 27 for spraying cleaning liquid on the blanket 7 during the cleaning process. The dampening arrangement 27 is provided in a third groove arranged parallel to and between the two rows of bristles 23a, 23b. A supply pipe or supply hose for supplying the dampening arrangement 27 with cleaning liquid can be connected to a connector part on the brush arrangement 26. In Fig. 6b a side view of the alternative brush arrangement 26 mounted on a pivoting arrangement 8 at one end of the brush arrangement 26 is shown, where the brush arrangement 26 is in the cleaning position. The piston 19 is retracted in the cylinder 20. The dampening arrangement 27 can be a plastic tubing provided with small holes for spraying the cleaning liquid onto the blanket 7. The diameter of the holes on the plastic tubing is preferably between 0.15 and 0.4 mm. A valve {not shown) is provided for controlling the supplying of cleaning liquid to the dampening arrangement 27. In Fig. 7 the brush arrangement 26 is shown with two rows of bristles 23a, 23b arranged in grooves of the brush arrangement 26. Between the rows of bristles 23a, 23b a dampening arrangement 27 is arranged in a third groove. The longitudinal direction C of the brush arrangement 26 is also shown. Cleaning liquid can also separately and optionally be provided by an applicator 5, as shown in Fig. 1. Such an applicator 5 is further described in EP-Bl-0 816 080 and has a roller, which is in contact with a cleaning liquid in the applicator and which may be brought into contact with the paper web 6, when cleaning is to be performed. The applicator 5, when not in operation, is closed by a cover preventing undesired matter from entering the applicator .5. The cleaning liquid in the applicator 5 is a solvent for the ink used in the printing press, normally an oil. The function of the cleaning arrangement is as follows. When blanket cleaning is desired, the press speed is decreased from the printing speed, and the supply of ink to an ink train therefore is disrupted. If an applicator 5 is used, an applicator roller, which is in contact with a cleaning liquid in the applicator 5, is brought into contact with the paper web 6 and impregnates it with cleaning liquid. The brush arrangement 4 is pivoted from the non-cleaning position to the cleaning position as the impregnated paper web 6 gets into contact with the blanket 7. The brush arrangement 4 starts to mechanically clean the surface of the blanket 7 in combination with cleaning liquid of the paper web 6. The dirt, such as printing ink, paper fibers, lint, and the like, will be removed by the paper web 6, which is continuously moving through the press 1 during the cleaning process. Additionally a dampening arrangement 27 on the brush arrangement 4 may spray the blanket 7 with complementary cleaning liquid. During the pivoting removing of the brush arrangement 4, the brush arrangement 4 can be displaced longitudinally to further minimize the risk of creating a pattern on the blanket 7 as the brush arrangement 4 is pivoted away from the blanket 7. The advantage of applying and removing the brush arrangement 4 with a pivoting movement to and from the blanket 7 is that a relative movement of the brush arrangement 4 to the blanket 7 minimizes the risk of creating a pattern on the blanket 7 during the removing action as is the case with prior art solutions with an axial removal action. The advantage of having rows of inclined brush bristles is that the contact surface of the bristles is larger on the blanket 7 and that the bristles will not remain in the same position all the time. The inclined bristles are to some degree self-cleaning as they gather lesser dirt compared with non-inclined bristles. Another advantage with the inclined bristles is that a rotation of the bristles on the blanket is achieved. Yet another advantage is that the cleaning result is substantially improved with the inclined bristles. It is possible to longitudinally displace the brush arrangement during the pivotal application to the blanket and during the pivotal removing of the brush arrangement from the blanket. The longitudinal displacement further reduces the risk of leaving a pattern of the brush arrangement on the blanket during the removing of the brush arrangement. The longitudinal displacement can be achieved by a cam surface that is arranged at one or both sides of the brush arrangement, so that it forces the brush arrangement to be displaced in a longitudinal direction relative to the longitudinal direction of the brush arrangement and the longitudinal direction of the blanket, during the pivotal movement of the brush arrangement. The cam surface can be designed in different ways to enable the longitudinal displacement of the brush arrangement, e.g. by making the displacement greater or smaller by increasing or decreasing the longitudinal difference between the starting point and the ending point of the cam surface. An advantage of using a plastic tubing for spraying cleaning liquid on the blanket is that no aerosols are created, but just a stream of cleaning liquid. The aerosols are non-desirable as they create a mist that affects the printing equipment and the working environment . The invention is not limited to the embodiment of two rows of bristles in the brush arrangement, but the invention is also working having only one row of bristles. The invention is not limited to the above-described examples or to the drawings showing examples of embodiments, but can be varied within the scope of the appended claims .

Claims

1. A brush arrangement (4; 26) for cleaning a blanket (7) on a rotatable blanket cylinder (3) in a printing press (1) from printing ink, paper fibers, lint and the like, the brush arrangement (4; 26) including a pivoting arrangement (8) for its application against the blanket cylinder (3), characterized in that the brush arrangement (4; 26) includes at least one row of bristles (23a; 23b) that are inclined in relation to an axis perpendicular to the longitudinal direction of the brush arrangement (4; 26) .

2. A brush arrangement (4; 26) according to claim 1, wherein the bristles are arranged in a profile and where the profile is exchangeably arranged in a groove on the brush arrangement (4; 26) .

3. A brush arrangement (4; 26) according to any preceding claim, wherein the bristles (23a, 23b) are inclined by 10-45 degrees in relation to the axis perpendicular to the longitudinal direction of the brush arrangement (4; 26) .

4. A brush arrangement (4; 26) according to any preceding claim, wherein two rows of bristles (23a, 23b) are parallelly arranged on the brush arrangement (4; 26) .

5. A brush arrangement (4; 26) according to claim 4, wherein the bristles in a first row of bristles (23a) are inclined in a first direction and the bristles in a second row of bristles (23b) are inclined in a second direction, and where the first and the second directions of the inclined bristles (23a, 23b) differ.

6. A brush arrangement according to any preceding claim, wherein the brush arrangement includes a spray device (27) arranged in a longitudinal direction of the brush arrangement.

7. A brush arrangement according to claim 6, wherein the spray device is a pipe (27) for supplying cleaning liquid is arranged in a longitudinal direction of the brush arrangement .

8. A brush arrangement according to any of claims 6 or 7, wherein the pipe (27) for supplying cleaning liquid is arranged in a groove parallel to the row of bristles (23a; 23b) .

9. A brush arrangement according to any of claims 7 or 8, wherein the pipe (27) is provided with small holes along its length.

10. A brush arrangement according to any of claims 7- 9, wherein the pipe (27) is connected to a liquid supply by a connecting part on the brush arrangement.

11. A brush arrangement (4; 26) according to any preceding claim, wherein the brush arrangement (4; 26) is provided with a cam surface enabling a longitudinal displacement of the brush arrangement (4; 26) during application to and removal from the blanket cylinder (3) .