The present invention generally relates to the wiping of rotatable intaglio printing cylinders of intaglio printing presses. More precisely, the present invention relates to an ink wiping system of an intaglio printing press and to an intaglio printing press comprising the same.
Intaglio printing presses are widely used in security printing for printing security documents, especially banknotes. Prior art intaglio printing presses are for instance disclosed in Swiss Patent No. CH 477 293 A5, European Patent Applications Nos. EP 0 091 709 A1, EP 0 406 157 A1, EP 0 415 881 A2, EP 0 563 007 A1, EP 0 873 866 A1, EP 1 602 483 A1, and International Applications Nos. WO 01/54904 A1, WO 03/047862 A1, WO 2004/026580 A1, WO 2005/118294 A1, WO 2011/077348 A1, WO 2011/077350 A1, WO 2011/077351 A1, all assigned to the instant Applicant.
The sheets are fed from the sheet feeder 2 onto a feeder table and then onto the impression cylinder 7. The sheets are then carried by the impression cylinder 7 to the printing nip between the impression cylinder 7 and the plate cylinder 8 where intaglio printing is performed. Once printed, the sheets are transferred from the impression cylinder 7 to a sheet transporting system 11 in order to be delivered to the delivery unit 4. The sheet transporting system 11 conventionally comprises an sheet conveyor system with a pair of endless chains driving a plurality of spaced-apart gripper bars for holding a leading edge of the sheets (the freshly-printed side of the sheets being oriented downwards on their way to the delivery unit 4), sheets being transferred in succession from the impression cylinder 7 to a corresponding one of the gripper bars.
During their transport to the sheet delivery unit 4, the freshly printed sheets are preferably inspected by an optical inspection system 5. In the illustrated example, the optical inspection system 5 is advantageously disposed along the path of the sheet transporting system 11, right after the printing unit 3. Such an optical inspection system 5 is already known in the art and does not need to be described in detail. Examples of optical inspection systems adapted for use as optical inspection system 5 in the intaglio printing press of
Before delivery, the printed sheets are preferably transported in front of a drying or curing unit 6 disposed after the inspection system 5 along the transport path of the sheet transporting system 11. Drying or curing could possibly be performed prior to the optical inspection of the sheets.
The inking system 9 comprises in this example four inking devices, three of which cooperate with a common ink-collecting cylinder or Orlof cylinder 9.5 (here a two-segment cylinder) that contacts the plate cylinder 8. The fourth inking device is disposed so as to directly contact the surface of the plate cylinder 8. It will be understood that the illustrated inking system 9 is accordingly adapted for both indirect and direct inking of the plate cylinder 8. The inking devices cooperating with the ink-collecting cylinder 9.5 each include an ink duct 9.10, 9.20, 9.30 cooperating in this example with a pair of inking rollers 9.11, 9.21 and 9.31, respectively. Each pair of inking rollers 9.11, 9.21, 9.31 in turn inks a corresponding chablon cylinder (also designated as selective inking cylinder) 9.13, 9,23, 9.33, respectively, which is in contact with the ink-collecting cylinder 9.5. As for the fourth inking device, it includes an ink duct 9.40, an additional inking roller 9.44, a pair of inking rollers 9.41 and a chablon cylinder 9.43, this latter cylinder being in contact with the plate cylinder 8. The additional ink roller 9.44 is necessary in this latter case as the fourth inking device 9.4 is used to directly ink the surface of the plate cylinder 8 which rotates in opposite direction as compared to the ink-collecting cylinder 9.5. As is usual in the art, the surface of the chablon cylinders 9.13, 9.23, 9.33 and 9.43 is structured so as to exhibit raised portions corresponding to the areas of the intaglio printing plates 8a, 8b, 8c intended to receive the inks in the corresponding colours supplied by the respective inking devices.
The ink wiping system 10, on the other hand, typically comprises a wiping tank 10.1, a wiping roller assembly 10.2 supported on and partly located in the wiping tank and contacting the plate cylinder 8, cleaning means 10.3 for removing wiped ink residues from the surface of the wiping roller assembly 10.2 using a wiping solution that is sprayed or otherwise applied onto the surface of the wiping roller assembly 10.2, and a drying blade 10.4 contacting the surface of the wiping roller assembly 10.2 for removing wiping solution residues from the surface of the wiping roller assembly 10.2. In the above known solution, as schematically illustrated in
A particularly suitable solution for an ink wiping system comprising a wiping roller assembly is disclosed in International Application No. WO 2007/116353 A1 which is incorporated herein by reference in its entirety.
The most common solution used for wiping excess ink from the surface of an intaglio printing cylinder is, as discussed hereinabove, to use a wiping roller assembly that rotates in the same direction as the intaglio printing cylinder. Such wiping roller assembly typically consists of a cylinder base made commonly of metal and bearing at least one layer of wiping material, preferably a layer of polymer material such as PVC material. The structure and manufacture of such wiping roller assemblies is for instance disclosed in U.S. Pat. Nos. 3,785,286, 3,900,595, 4,054,685 and International Applications Nos. WO 2007/031925 A2, WO 2007/031927 A2, WO 2007/034362 A2 which are incorporated herein by reference.
As mentioned above, such wiping roller assembly is typically supported on and partly located in a wiping tank for rotation against the surface of the intaglio printing cylinder, the surface of the wiping roller assembly being cleaned from wiped ink residues using a wiping solution that is commonly sprayed onto the surface of the wiping roller assembly. It is to be understood that, in operation, the wiping roller assembly is supported in an upper section of the wiping tank so that a lower portion thereof can be sprayed with the wiping solution, used wiping solution being recovered in a lower section of the wiping tank.
With such known solutions, the wiping pressure between the intaglio printing cylinder and the wiping roller assembly is adjusted by playing with the position of the axis of rotation of the wiping roller assembly with respect to the axis of rotation of the intaglio printing cylinder. This is typically achieved by using two adjusting mechanisms acting on the two ends of the wiping roller assembly, such by means of eccentric bearings. Adjustment mechanisms for adjusting the wiping pressure between a wiping roller assembly and an intaglio printing cylinder are for instance disclosed in European Patent Applications Nos. EP 0 475 890 A1, EP 0 526 398 A1, and U.S. Pat. Nos. 2,987,993, 3,762,319. More recently, a solution has been proposed by the present Applicant with a view to allow selective adjustment of the wiping pressure at a plurality of locations along the contact portion between the wiping roller assembly and the intaglio printing cylinder. Such a solution is disclosed in greater detail in pending European patent applications Nos. EP 11166852.1 and EP 11166854.7 of May 20, 2011 both entitled “INK WIPING SYSTEM FOR AN INTAGLIO PRINTING PRESS”.
Maintenance operations of the known ink wiping systems are time-consuming as the wiping roller assembly is a relatively heavy component to manipulate, which typically necessitates the use of a crane to remove the wiping roller assembly from the wiping tank as already mentioned. In addition, the use of a crane necessary implies that the wiping roller assembly is extracted from or lowered onto the wiping tank along a substantially vertical trajectory, which in turn necessitates movement of the entire wiping tank, including the wiping roller assembly, to a retracted maintenance position (as for instance indicated by reference numeral 10′ in
An improved solution is thus required.
A general aim of the invention is therefore to provide an improved ink wiping system for use in an intaglio printing press as compared to the solutions already known in the art.
A further aim of the invention is to provide such an ink wiping system that facilitates maintenance operations, in particular cleaning of the ink wiping system.
Yet another aim of the invention is to provide such an ink wiping system that allows an easy and quick exchange of a used wiping roller assembly by a new wiping roller assembly.
These aims are achieved thanks to the ink wiping system defined in the claims.
According to a first aspect of the invention, there is accordingly provided an ink wiping system of an intaglio printing press comprising a wiping tank and a rotatable wiping roller assembly supported on and partly located in the wiping tank for wiping excess ink from the surface of a rotatable intaglio printing cylinder of the intaglio printing press, the ink wiping system comprising a wiping roller retracting device which forms an integral part of the ink wiping system and is adapted to be coupled to the wiping roller assembly to move the wiping roller assembly between a working position where the wiping roller assembly is supported on and partly located in the wiping tank for cooperation with the intaglio printing cylinder and a parking position where the wiping roller assembly is retracted out of the wiping tank and away from the intaglio printing cylinder, wherein, in the working position of the wiping roller assembly, the wiping roller retracting device is coupled to the wiping roller assembly. According to this first aspect of the invention, the ink wiping system includes, at the parking position, a storage section adapted to receive the wiping roller assembly which is retracted by the wiping roller retracting device.
Such an ink wiping system greatly facilitates maintenance operations in that the wiping roller assembly can simply be retracted to the parking position by means of the wiping roller retracting device, thereby freeing and allowing full access to the wiping tank for cleaning purposes. Once the cleaning operations have been completed, the wiping roller assembly can be moved back to its working position.
The storage section can advantageously be located immediately below the wiping tank, which ensures a very compact configuration and allows unobstructed access to the wiping tank.
In an advantageous variant, the wiping roller retracting device can be adapted to release the wiping roller assembly in the parking position. In such a context, the storage section is preferably provided with a wiping roller holding device adapted to hold the wiping roller assembly in the parking position upon release by the wiping roller retracting device, which wiping roller holding device may advantageously comprise first and second arms adapted to be brought into cooperation with a respective one of first and second extremities of the wiping roller assembly.
According to a preferred variant of this first aspect of the invention, the ink wiping system further comprises an interlocking mating guide designed to guide and position a trolley with respect to the ink wiping system and along a path of the wiping roller retracting device, the trolley being designed to allow exchange of a used wiping roller assembly by a new wiping roller assembly. Advantageously, the wiping roller retracting device is adapted to release the used wiping roller assembly in the parking position, prior to coupling of a trolley to the interlocking mating guide and the storage section is provided with means for transferring the used wiping roller assembly from the storage section onto the trolley coupled to the interlocking mating guide.
According to a second aspect of the invention (which second aspect can be implemented in combination with the above first aspect as mentioned above) there is provided an ink wiping system of an intaglio printing press comprising a wiping tank and a rotatable wiping roller assembly supported on and partly located in the wiping tank for wiping excess ink from the surface of a rotatable intaglio printing cylinder of the intaglio printing press, the ink wiping system comprising a wiping roller retracting device which forms an integral part of the ink wiping system and is adapted to be coupled to the wiping roller assembly to move the wiping roller assembly between a working position where the wiping roller assembly is supported on and partly located in the wiping tank for cooperation with the intaglio printing cylinder and at least one retracted position where the wiping roller assembly is retracted out of the wiping tank and away from the intaglio printing cylinder, wherein, in the working position of the wiping roller assembly, the wiping roller retracting device is coupled to the wiping roller assembly. According to this second aspect of the invention, the ink wiping system further comprises an interlocking mating guide designed to guide and position a trolley with respect to the ink wiping system and along a path of the wiping roller retracting device, which trolley is designed to allow exchange of a used wiping roller assembly by a new wiping roller assembly.
Such an ink wiping system likewise greatly facilitates maintenance operations in that a used wiping roller assembly can simply be transferred onto a trolley coupled to the interlocking mating guide, while a new wiping roller assembly can be transferred from a trolley coupled to the interlocking mating guide to the working position. It will become apparent from the following description that one and a same trolley can be used to transport the new wiping roller assembly to the ink wiping system and evacuate the used wiping roller assembly, in which case the aforementioned storage section can be exploited as temporary storage area (see illustrations of
In an advantageous variant, the wiping roller retracting device can be adapted to move and release the used wiping roller assembly directly onto a trolley coupled to the interlocking mating guide.
In yet another advantageous variant, the wiping roller retracting device can be adapted to take up the new wiping roller assembly sitting on a trolley coupled to the interlocking mating guide and move the new wiping roller assembly directly from the trolley to the working position.
In an advantageous embodiment of the invention, the wiping roller retracting device is adapted to pivot the wiping roller assembly away from and to the working position. In this context, the wiping roller retracting device may advantageously comprise first and second rotatable supporting arms adapted to be coupled at one end to a respective one of first and second extremities of the wiping roller assembly. The wiping roller retracting device is preferably pivotally supported onto the wiping tank.
In yet another advantageous embodiment, the wiping tank can be fixedly secured to a machine frame of the intaglio printing press and be unable to move with respect to the machine frame, which solution allows for a highly robust ink wiping system configuration.
There is further provided an intaglio printing press comprising an ink wiping system as provided above.
Further advantageous embodiments of the ink wiping system form the subject-matter of the dependent claims and are discussed below.
Other features and advantages of the present invention will appear more clearly from reading the following detailed description of embodiments of the invention which are presented solely by way of non-restrictive examples and illustrated by the attached drawings in which:
Within the scope of the present invention, the expression “intaglio printing cylinder” designates either a cylinder whose surface is provided with intaglio patterns engraved directly onto the circumference of the cylinder or a plate cylinder carrying on its circumference at least one intaglio printing plate with engraved intaglio patterns (the second solution being now more common in the art). In the following description, it will be assumed for the sake of illustration that the intaglio printing cylinder is a plate cylinder carrying several intaglio printing plates on its circumference.
Also shown in
According to the invention, the ink wiping system 100 comprises a wiping roller retracting device (not specifically illustrated in
According to the invention, it shall be appreciated that, in the working position of the wiping roller assembly, the wiping roller retracting device (which is an integral part of the ink wiping system) is coupled to the wiping roller assembly. This contrasts with the known solution discussed in the preamble hereof, where a separate crane is only coupled to the wiping roller assembly during maintenance operations, which maintenance operations require retraction of the entire wiping tank to a maintenance position (as pictured in
Preferably, as schematically illustrated in
Movement of the wiping roller assembly 102 between the working position W and the parking position P is preferably done via a suitable drive, such as an electric motor, servo-motor or the like, or an adequate pneumatic or hydraulic system.
The wiping tank 101 is typically provided with adequate means designed to remove and clean the surface of the wiping roller assembly 102 from wiped ink residues. This can advantageously be carried out by means of a system as disclosed in International Application No. WO 2007/116353 A1 which is incorporated herein by reference in its entirety.
Reference numerals 50 and 55 in
The embodiment of
If required, the wiping roller retracting device 150 can be operated to at least temporarily move the wiping roller assembly 102 to a storage section 110 that is advantageously provided immediately below the wiping tank 101.
In the illustrated example, it is to be understood that the two rotatable supporting arms 151, 152 are adapted to move, perpendicularly to the axis of rotation of the wiping roller assembly 102, with corresponding spaces provided between the side frames 50 and the lateral side walls of the wiping tank 101. As shown in
One will now describe operation of the wiping roller retracting device 150 in case of replacement of a used wiping roller assembly by a new wiping roller assembly. For the sake of explanation, the used wiping roller assembly will be designated in
In the context of
Before actuating the wiping roller retracting device 150, the wiping roller assembly 102 is uncoupled from the various functional components that are typically associated to operation of the wiping roller assembly 102 during printing operations. Such functional components, which are not specifically illustrated, including in particular a wiping roller drive for driving the wiping roller assembly 102 into rotation and a thermoregulation unit for regulating the temperature of the wiping roller assembly 102. In the context of the present invention, it suffices to understand that suitable coupling systems are provided to ensure that the wiping roller drive and thermoregulation unit can be uncoupled from and coupled to the wiping roller assembly 102 (whether manually or semi-automatically).
Once the used wiping roller assembly 102 has been moved to the position where it rests onto the support portion 180a of the trolley 180 (which position is designated by reference T in
Once the wiping roller assembly 102 has been released onto the trolley 180, the supporting arms 151, 152 are moved to an intermediate position I as illustrated in
A new wiping roller assembly 102* can then be brought to the ink wiping system 100′ which has been freed from the used wiping roller assembly 102, as illustrated by
The ink wiping system 100″ of
The difference between the ink wiping system 100″ of
In addition, a different trolley is used in this other embodiment, namely a trolley, designated by reference numeral 200, which comprises upper and lower support portions 200a and 200b for supporting the wiping roller assembly (see
In this other example, the used wiping roller assembly 102 is first moved to the parking position P by means of the wiping roller retracting device 150 (see
Once this has been done, a new wiping roller assembly 102* can be brought to the ink wiping system 100″ by means of the trolley 200, which trolley 200 is guided and positioned with respect to the ink wiping system 100″ by means of the interlocking mating guide 115, in a manner similar to the embodiment of
Once the trolley 200 with the new wiping roller assembly 102* has been coupled to the ink wiping system 100″, the wiping roller retracting device 150 can be actuated to bring the arms 151, 152 from the intermediate position I (
The wiping roller retracting device 150 can then be actuated to move the new wiping roller assembly 102* directly from the upper portion 200a of the trolley 200 to the working position W (see
The trolley 200, freed of the new wiping roller assembly 102*, is now ready to receive the used wiping roller assembly 102 that is being temporarily stored in the storage section 110. In the illustrated example, this is achieved by means of the wiping roller holding device 170, the two arms 171, 172 thereof being advantageously designed as telescopic arms. As illustrated in
It will accordingly be understood that the embodiment of
Various modifications and/or improvements may be made to the above-described embodiments without departing from the scope of the invention as defined by the annexed claims. For instance, while the disclosed embodiments make use of a pair of rotatable arms designed to pivot the wiping roller assembly about an axis of rotation, other arrangements could potentially be provided to move the wiping roller assembly between the working position and the parking position. A pivoting movement is however of substantial advantage in the context of the present invention, especially in view of the resulting compactness of the system.
In addition, as an alternative to the procedure illustrated in
Number | Date | Country | Kind |
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12158948.5 | Mar 2012 | EP | regional |
Filing Document | Filing Date | Country | Kind |
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PCT/IB2013/051920 | 3/11/2013 | WO | 00 |