Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41F—PRINTING MACHINES OR PRESSES
  • B41F27/00—Devices for attaching printing elements or formes to supports
  • B41F27/10—Devices for attaching printing elements or formes to supports for attaching non-deformable curved printing formes to forme cylinders
  • B41F27/105—Devices for attaching printing elements or formes to supports for attaching non-deformable curved printing formes to forme cylinders for attaching cylindrical printing formes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41F—PRINTING MACHINES OR PRESSES
  • B41F16/00—Transfer printing apparatus
  • B41F16/0006—Transfer printing apparatus for printing from an inked or preprinted foil or band
  • B41F16/002—Presses of the rotary type
  • B41F16/0033—Presses of the rotary type with means for applying print under pressure only, e.g. using pressure sensitive adhesive
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41F—PRINTING MACHINES OR PRESSES
  • B41F30/00—Devices for attaching coverings or make-ready devices; Guiding devices for coverings
  • B41F30/02—Devices for attaching coverings or make-ready devices; Guiding devices for coverings attaching to impression cylinders
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41F—PRINTING MACHINES OR PRESSES
  • B41F21/00—Devices for conveying sheets through printing apparatus or machines
  • B41F21/10—Combinations of transfer drums and grippers
  • B41F21/104—Gripper details
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41F—PRINTING MACHINES OR PRESSES
  • B41F27/00—Devices for attaching printing elements or formes to supports
  • B41F27/12—Devices for attaching printing elements or formes to supports for attaching flexible printing formes
  • B41F27/1262—Devices for attaching printing elements or formes to supports for attaching flexible printing formes without tensioning means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41F—PRINTING MACHINES OR PRESSES
  • B41F31/00—Inking arrangements or devices
  • B41F31/16—Continuous, e.g. endless, band apparatus

Definitions

• the present invention relates to devices and methods for securing cylinder jackets to cylinders, such as used in printing systems.
• Printing can be divided into direct and indirect processes, depending on the surface upon which an ink image is first deposited. In the former printing method, the ink image is directly deposited on a printing substrate, whereas in the latter process the ink image is first formed on an intermediate surface.
• Conventional offset printing processes include lithography, flexography, gravure and screen printing. But the ink image can also be digitally created by a number of techniques.
• Printing devices can, for instance, use an indirect inkjet printing process in which an inkjet print head is used to deposit ink droplets forming an ink image onto the surface of an intermediate transfer member, which is then used to transfer the image onto a substrate.
• the intermediate transfer member may be any suitable plate, drum or endless flexible belt.
• This latter type of indirect printing may lead to several problems, such as the abrasion of a surface as a result of repeated contact with another or dirt and detritus accumulating, with time, on the ITM and on surfaces contacting it.
• problems can be aggravated when a relatively high pressure is applied to urge contact between the different surfaces, for instance the outer surface of an impression cylinder at the image transfer location may experience an increased rate of deterioration.
• back transfer can cause dried ink and/or other unwanted materials to transfer from the previously printed image to the surface of the‘perfecting’ impression cylinder, adding one more cause for decline in the properties of the cylinder surface.
• Printing cylinders may include more than one cylinder jacket along a circumferential direction of the cylinder.
• GB 764,560 discloses a device for clamping a printing plate to a printing cylinder that employs a lever mounted in a recess in the printing cylinder and a magnet to retain the lever in a position in which it clamps an end of the printing plate against the cylinder.
• An aim of the invention is inter alia to enable quick and effective attachment of jackets to cylinders which have no such jacket attachment arrangements provided.
• a jacket-securing arrangement for mounting in a cylinder, which cylinder has an outer surface and at least one recess in the outer surface for receiving an inwardly turned edge of a replaceable jacket overlying at least part of the outer surface of the cylinder, wherein the jacket-securing arrangement is mountable within the recess so as not to project beyond the outer surface of the cylinder when the jacket is secured thereto, and includes a clamping lever pivotable about a shaft located within the recess between a clamping position in which the edge of the replaceable jacket is clamped between the lever and a side wall of the recess and a release position in which the lever is spaced from the side wall of the recess, a magnet being provided to retain the lever in the clamping position, wherein the clamping lever is formed of two or more members assembled around the shaft and defining between them a bearing surface engaging an outer surface of the shaft.
• the cylinder in which the jacket securing arrangement can be advantageously implemented is a cylinder of a printing system, such as a cylinder for transporting a printing substrate between stations of a printing system, the transported substrate being optionally subjected to a step of the printing process while being displaced by the cylinder.
• the cylinder may alternatively be named after the printing step performed therewith, for instance, a cylinder transporting a substrate during impression of an ink image to the substrate can be termed an impression cylinder or a perfecting cylinder, if the impression is to be made on a rear side of a substrate previously printed on its front side.
• Impression cylinders perfecting cylinders and mere transport cylinders (e.g., simply ensuring motion of a substrate along a path from a feeding stack to a delivery pile) often include an arrangement for gripping a leading or tailing edge of a substrate sheet as it is being transported. Therefore, the illustrative foregoing cylinders of a printing system, can be individually or collectively referred to as substrate transport cylinders.
• the substrate gripping arrangement each such cylinder may include, may comprise a plurality of grippers mounted on a gripper shaft located within a recess in the cylinder. Individual grippers can be fixedly mounted at spaced intervals along the gripper shaft and can be moved between positions in which they grip and release the substrate.
• the shaft about which the clamping levers of the jacket-securing arrangement are pivotable may be the gripper shaft of an arrangement for gripping an end of substrate sheets transported by the cylinder.
• the clamping levers may be disposed in spaces on the gripper shaft between the substrate grippers. Because the clamping levers are formed of two (or possibly more) members that can be assembled around the shaft while the shaft remains in situ, enables the clamping levers to be retrofitted in existing impression cylinders.
• the shaft about which the clamping levers of the jacket-securing arrangement are pivotable may be a dual coaxial shaft.
• the grippers may be mounted on one of the coaxial shaft and the clamping levers on the other, the clamping levers being disposed on their shaft in regions corresponding to spaces on the gripper shaft between the substrate grippers.
• a cylinder the cylindrical surface of the cylinder including a recess for receiving an inwardly turned edge of a replaceable jacket overlying at least part of the outer surface of the cylinder, and a shaft located in the recess, wherein the cylinder is further provided with a jacket-securing arrangement as briefly described above and further detailed herein.
• the cylinder is for a printing system, optionally for transporting a printing substrate.
• a printing system comprising a cylinder having a cylindrical surface, a recess in the cylindrical surface for receiving an inwardly turned edge of a replaceable jacket overlying at least part of the outer surface of the cylinder, a shaft located in the recess, wherein the cylinder is further provided with a jacket-securing arrangement as briefly described above and further detailed herein.
• the cylinder of the printing system is for transporting a printing substrate.
• kits the parts of which can be mounted around a shaft to form a jacket-securing arrangement as briefly described above and further detailed herein.
• the kit can be used for mounting the jacket-securing arrangement around the shaft of cylinder of a printing system, the cylinder optionally serving for transporting a printing substrate.
• Figure 1 is an elevation-view schematic illustration of a printing system according to embodiments of the present invention.
• Figure 2 is a perspective view of an impression cylinder having cylinder gaps, according to embodiments of the present invention.
• Figures 3A and 3B are, respectively, a schematic cross-section (elevation) view and a partial top (plan) view of an impression cylinder with gripper shaft and grippers, according to embodiments of the present invention.
• Figure 4 is an end (elevation) projection view of the impression cylinder and associated equipment of Figure 2, with a cylinder jacket mounted and secured to the cylinder, according to embodiments of the present invention.
• Figures 5A and 5B are, respectively, a top (plan) view and an end (elevation) view of a cylinder jacket according to embodiments of the present invention.
• Figure 5C shows an alternative partial end view of the trailing portion of a cylinder jacket according to embodiments of the present invention.
• Figure 6 is schematic illustration of jacket tabs of the jacket of Figure 5 A, and corresponding gripper shaft, grippers and inter-gripper regions of an impression cylinder, according to embodiments of the present invention.
• Figure 7 is an annotated illustration of the jacket tabs of Figure 6.
• Figure 8 is an annotated illustration of the gripper shaft, grippers and inter-gripper regions of Figure 6.
• Figures 9A and 9B are, respectively, side and top views of a jacket-securing arrangement according to embodiments of the present invention, in an assembled state on a gripper shaft.
• Figures 9C and 9D are, respectively, elevation views of the jacket-securing arrangement of Figure 9A, in a first disassembled state showing complete disassembly, and in a second disassembled state using a linkage arrangement.
• Figures lOA and IOC are, respectively, elevation views of a jacket-securing arrangement that is magnetically securing a j acket tab to a surface of a cylinder gap of the impression cylinder of Figure 2, according to preferred and alternative embodiments of the present invention.
• Figure 10B is a detail view of a jacket tab with an affixing element on one side and a friction pad on the other side, according to embodiments of the present invention.
• Figures 11 A and 1 IB are, respectively, elevation views of a jacket-securing arrangement in an assembled state on a gripper shaft, in a first rotated position and a second rotated position, according to embodiments of the present invention.
• Figure 12 is an elevation view of a jacket-securing arrangement in the assembled state and in the first rotated position, showing the location of a force on a force-receiving surface of the jacket-securing arrangement, said force being effective for rotating the jacket-securing arrangement away from the first rotated position and in the direction of the second rotated position, according to embodiments of the present invention.
• Figure 13 is a partial perspective view of the cylinder of Figure 2, including a bracket provided for applying the force of Figure 12 to a plurality of jacket-securing arrangements, according to embodiments of the present invention.
• Figure 14A is a schematic illustration of thickness options for force-receiving portion of a jacket-securing arrangement according to embodiments of the present invention.
• Figure 14B is an illustration of the integration of the thickness options of Figure 14A with the elevation view of Figure 12.
• Figure 14C is an illustration of respective rotation angles associated with two of the thickness options of Figures 14A and 14B.
• Figure 15 shows the elevation view of Figure 3 with two cylinder jackets mounted and secured thereto, according to embodiments of the present invention.
• Figure 16 is a partial view of one of the two cylinder gaps of the impression cylinder of Figure 15, showing arrangements for securing the end of the jacket that is not the end secured by the jacket-securing arrangement of Figure 10A, according to embodiments of the present invention.
• Figure 17 is an end (elevation) view of a perfecting cylinder suitable for use in a printing system configured for duplex printing, with a cylinder jacket mounted and secured thereto, according to embodiments of the present invention.
• Figure 18 is an elevation view of a jacket-securing arrangement for use with the perfecting cylinder of Figure 17, according to embodiments of the present invention.
• Figure 19 shows a flowchart of a method for installing a jacket-securing arrangement and a cylinder jacket, according to embodiments of the present invention.
• Figure 20 shows a flowchart of a method for replacing a cylinder jacket on a cylinder, according to embodiments of the present invention.
• subscripted reference numbers may be used to designate multiple separate appearances of elements of a single species, when in a drawing or not; for example: 10i is a single appearance (out of a plurality of appearances) of element 10.
• 10i is a single appearance (out of a plurality of appearances) of element 10.
• the same elements can alternatively be referred to without subscript (e.g. , 10 and not 10i) when not referring to a specific one of the multiple separate appearances, i.e. , to the species in general.
• an ink image is first formed (e.g. , selectively deposited or activated) on a surface of an intermediate transfer member (ITM), and transferred from the surface of the intermediate transfer member to a substrate (i.e. sheet substrate or web substrate).
• a substrate i.e. sheet substrate or web substrate.
• the location in the printing system at which the ink is deposited or the image otherwise formed (e.g. , by application of energy) on the ITM is referred to as the“image forming station”.
• the ITM comprises a flexible or endless“belt” and the terms“belt” and“ITM” are used interchangeably in such descriptions.
• the ITM being, as mentioned, additionally able to include a more rigid body, the ITM being an outer surface of a plate or a drum.
• the surface upon which the ink image is deposited or formed can also be referred to as the“release surface”, in view of its ability to transfer the ink image at an impression station.
• FIG. 1 is a schematic diagram of an example of a printing system 100 for indirect printing according to some embodiments of the present invention.
• ITM intermediate transfer member
• FIG. 1 comprises an intermediate transfer member (ITM) 210 comprising a flexible endless belt mounted over a plurality of guide rollers 232, 240, 260, 253, 255, 242.
• ITM intermediate transfer member
• This figure shows aspects of a specific configuration relevant to discussion of the invention, and the shown configuration is not limited to the presented number and disposition of the rollers, nor is it limited to the shape and relative dimensions, all of which are shown here for convenience of illustrating the system components in a clear manner.
• the ITM 210 rotates in the clockwise direction relative to the drawing, as indicated by arrow 2012. This direction can also be referred to as the“printing direction”.
• the printing system 100 can further comprise:
• an image forming station 212 comprising print bars, in the number of four in the present illustration: 222A-222D (each designated one of C - for Cyan, M - for Magenta, Y - for Yellow and K - for black).
• the image forming station 212 is configured to form ink images 50 (only a few being shown the figure) upon a surface of the ITM 210 (e.g., by droplet deposition thereon);
• an impression station 216 where the ink images 50 are transferred from the surface of the ITM 210 to a substrate 231.
• the substrate 231 is shown as sheet-fed substrate, such as paper or carton product, but it can alternatively be a continuous-feed (web) substrate.
• the substrate transport system conveying the substrate from a feeding end to a delivery end via the impression station is not shown in the figure.
• the impression station 216 comprises an impression cylinder 220 and a pressure cylinder assembly 318 which includes a pressure cylinder 218 and an optional compressible blanket 219 disposed at least around a large portion of the circumference of the pressure cylinder.
• the impression cylinder 220 is rotatable in the direction indicated by arrow 2010, so as to transport sheets of substrate 231 from a supply stack to a delivery one.
• the pressure cylinder 218 can rotate synchronously with the impression cylinder 220 but in the opposite direction, as shown by arrow 2011.
• the respective rotation of the cylinders forming the impression station can be synchronized through the use of gears and/or bearers on the corresponding cylinders.
• the line of contact between the two may be referred to as the“impression nip”.
• Disengagement may be achieved by increasing the distance between the axes of rotation of the cylinders, for instance, by lifting-up the pressure assembly 318.
• the axes of rotation of the cylinders may remain at a same spacing enabling contact, however at least one of the cylinders include a gap, so that as the gap reaches the nip, contact cannot be made with the circumference of the facing cylinder.
• a printing system can include additional features and components such as, for example, a different number of components in the previously described stations (e.g . , a different number of print bars in the imaging station), a conditioning station, a cooling station or a cleaning station, to respectively condition (e.g., chemically and/or physically treat), cool or clean the surface of the GGM, if desired.
• the printing system can include arrangements for performing duplex printing (i.e. printing a second image on the second side of a substrate printed on its first side), the printing system including an additional substrate transport system allowing to feed the other side of the substrate to the impression station or including a second (‘perfecting’) impression cylinder for that purpose.
• the cylinder 220 has a first cylinder gap 320i and a second cylinder gap 3202.
• a cylinder gap as is known in the printing industry, is a recess in the circumference of a printing cylinder for housing and/or anchoring ancillary equipment within the gap.
• the remainder of the cylinder circumference - from the trailing edge of a first cylinder gap (e.g. , 320i) to the leading edge of a second cylinder gap (e.g., 3202) - is smooth.
• grippers can be used to grip sheets of substrate 231 on impression cylinders (and on some other types of cylinders, which are not relevant to this disclosure).
• Grippers serve to releasably engage the sheets on the impression cylinder and to maintain them thereon, often by way of gripper pads at one end of gripper fingers pivotably mounted on an axis.
• Figures 3A and 3B schematically illustrate an impression cylinder 220 wherein a plurality of grippers 350 attached to gripper shaft 351 are substantially recessed (meaning, in this disclosure: either completely recessed, or at least 90% recessed, or at least 80% recessed) inside the impression cylinder gap 320 so as to substantially not extend (meaning: either the grippers 350 do not extend at all, or at most of the grippers 350 extend by 10% or 20%) beyond the circumference of the impression cylinder, i.e.. the virtual cylinder where the cylindrical circumference would be without the discontinuity of the impression cylinder gap 320.
• One of the reasons for selecting a design with recessed grippers can be so as to avoid damage or excessive wear of the ITM 210 as it traverses the impression station 216.
• FIG. 3A is a cross-sectional view showing only a single gripper 350
• Fig. 3B is a partial top view showing a plurality of grippers 350 spaced along the length of gripper shaft 351.
• the grippers 350 are not necessarily evenly spaced along the length of the shaft 351.
• the number and spacing of grippers are illustrative and there can be different numbers of grippers and/or different spacing of grippers in other examples.
• the grippers 350 extend from the gripper shaft 351 and overlap the trailing edge of the cylinder gap 320 (in the direction of rotation 2010).
• the grippers 350 can be seen, in both Figs. 3A and 3B, to overlap a part of the surface of the impression cylinder 220 beyond the edge of the cylinder gap 320.
• cylinder jackets can be provided to cover a surface of a cylinder, including, by way of example, impression cylinders.
• such jackets should be easy to mount on or remove from the cylinder the cylindrical surface of which they are due to at least partly envelop.
• the cylinder jackets can also be referred to as being“releasable jacket(s)” and to the extent they are optionally changed or discarded they may also be referred to as“replaceable jacket(s)”.
• Figure 4 shows another view of an impression cylinder with a jacket 225 attached on one side of the cylinder, covering the cylinder surface on one smooth circumferential surface between cylinder gaps 320.
• the plurality of grippers 350 shown in Fig. 3B may tend to interfere with the attachment of the jacket 225 at its leading edge, i.e., at the edge where grippers 350 are extended from the cylinder gap 320 and cover a small part of the cylinder surface.
• FIG. 5A Details of the jacket 225, illustrating an example of how the potential blockage by grippers 350 at the edge of the cylinder gap 320 can be overcome, can be seen in Figures 5A and 5B.
• An examination of Fig. 5B will reveal that the jacket 225 is the same as the one mounted on the cylinder 220 in Fig . 4, but rotated here for convenience .
• a plurality of folded or foldable tabs 229 is provided on the leading edge of the j acket 225 the leading edge in cylinder rotation direction 2010.
• the tabs are shown in an unfolded state in Fig. 5A and in a folded state in Fig. 5B.
• the tabs 229 can be folded at first folding line 226i so as to facilitate mounting and securing of the jacket 225 on the cylinder 220.
• the‘folding’ may in some embodiments be more like‘bending,’ i.e. , with a larger radius that does not crease or create a distinct comer.
• a trailing portion 227 is folded (or bent) at a second folding line 2202for purposes of mounting and securing on the cylinder 220.
• the folding of a flat jacket trailing edge shall preferably be by more than 90°, so that the angle resulting in the folded angle of the jacket be of 90° or less, facilitating the retention in the recess of a jacket being“tensioned” at its leading edge by a jacket securing arrangement according to the present teachings.
• the foldable trailing portion 227 on the trailing edge of the jacket 225 need not be a solid strip as illustrated, and in some examples of suitable jackets 225, the foldable portion 227 can comprise multiple portions including, for example, tabs similar to tabs 229. As illustrated in Fig. 5C, the foldable portion 227 can include multiple foldable portions that may be designed in accordance with a surface of a specific cylinder gap 320, or of equipment therein, to which the foldable portion conforms when mounted on a cylinder 220.
• the folding of the tabs 229 and the trailing portion 227 can be factory-performed or supplier-performed, i. e. , a jacket 225 is provided with tabs 229 and trailing portion 227 already folded.
• the jacket 225 can be provided unfolded, and the folding is performed, e.g. , by a jacket installer, whether in situ by placing the jacket 225 on a cylinder 220 and folding the tabs 229 and trailing portion 227 around the edges of the cylinder gaps 320, or as part of preparing a jacket 225 for installation by using a folding jig ⁇
• Figure 6 illustrates schematically how the provision of tabs on the leading edge of ajacket can help to overcome the partial and intermittent‘blocking’ of the edge of the cylinder gap by the grippers extending from the cylinder gap so as to cover part of the cylinder surface.
• the underlying concept is that a folded tab 229 can be inserted between each pair of adjacent grippers 350.
• the gripper shaft 351 and fourteen grippers 350 of Fig. 3B are shown. Between each pair of grippers is a region of space, such that there are thirteen spaces defined by the fourteen grippers.
• inter-gripper space Three of these regions are marked as “other inter-gripper space.” These spaces are so marked because, according to a non-limiting example, the presence of other equipment (not shown) in the spaces prevent the insertion of a jacket tab.
• a common type of equipment present in such cases is a shaft bearing that secures the gripper shaft and allows it to rotate through at least the rotation range necessary for opening and closing grippers when gripping and‘un-gripping’ sheets of substrate on the surface of the impression cylinder 220.
• the other ten between-gripper spaces constitute inter-gripper regions 353 which can be used to accommodate jacket tabs 229.
• N is equal to 10
• the efficacy of this notation is illustrated when considering the leading edge of jacket 225 having tabs 229 extending therefrom, on the right side of the diagram of Fig. 6. It can be seen that, in this example, ten tabs 229 corresponding to the ten inter-gripper regions 353 are provided, and that for every REGION(n) from REGION(l ) to REGION(l 0), there is a corresponding TAB(n), i. e.. from TAB(l) to TAB(10).
• the value of N is the same for inter-gripper regions and for tabs.
• TAB-WIDTH(n) is a one-dimensional array of values of widths corresponding to respective tabs TAB(n). If a tab 229 has a substantially rectangular shape (‘substantially’ meaning except as modified for manufacturing purposes, e.g. , because of cutting radiuses) as per preferred embodiments and as illustrated throughout this disclosure, then the value of TAB- WIDTH(n) is obviously the width of TAB(n) as shown in Fig. 7. In alternative embodiments in which the width is irregular, then TAB-WIDTH (n) can equal the maximum value of the width at any point on the TAB(n). Nonetheless, a substantially rectangular shape can be preferable so as to best facilitate use of the tabs in securing a jacket to the cylinder.
• TAB-SPACING(n) is a one-dimensional array of values of spacing corresponding to respective tabs TAB(n). Spacing of tabs can be assessed in different ways. In the example of Fig. 7, TAB-SPACING(n) is assessed as the distance from a lateral edge of the jacket 225 to the‘beginning’ of the respective tab, i.e., to the‘bottom’ of the tab in the plan view of Fig. 7. Alternatively, spacing can be from tab to tab (beginning -to-beginning, ending- to-ending or centerline to centerline), from jacket lateral edge to centerline of tab, from jacket lateral edge to ending of tab, and so on.
• Figure 8 illustrates one-dimensional arrays REGION-SPACING(n) and REGION-WIDTH (n) respective of the set of inter-gripper regions REGION(n) described earlier in the discussion of Fig. 6.
• TAB-SPACING(n) be substantially equal to REGION-SPACING(n), and it is also preferable that TAB-WIDTH(n) be no larger than REGION-WIDTH (n) . It is especially preferable that each TAB-WIDTH(n) be smaller than the corresponding REGION- WIDTH (n) .
• Printing cylinders commonly include a ferromagnetic material such that it is possible to secure a jacket to the cylinder using magnets.
• the area of a cylinder gap in which such magnetic securing is likely to take place is also used to house the gripper shaft and set of grippers.
• the magnet may have a magnetic pull strength of more than 5 kg or more than 10 kg or more than 20 kg.
• a jacket-securing arrangement 270 comprises a two-armed bell-crank clamping lever formed of first and second members 272, 274.
• a jacket- securing arrangement 270 may include more than two members.
• first member 272 may itself be formed of two sub-members, which may, by way of example, facilitate the attachment of a magnet 280 to one of the sub-members prior to securing it to the other sub member, so as to form the shape sought for the first member.
• jacket-securing arrangement 270 of Fig. 9A is shown in an assembled state.
• the assembled state of jacket-securing arrangement 270 according to some embodiments satisfies the following features:
• the two members 272, 274 are releasably attached to each other. This can be accomplished effectively, for example, by providing one or more pre-drilled holes 267, e.g., for screws or bolts, passing through the second member 274, and corresponding receiving portion(s) (not shown - they are obscured in Fig. 9B by second member 274), e.g. , threaded receptacles in the first member 272 for receiving the screws or bolts.
• the screws are captive screws.
• Two holes 267 are shown so as to accommodate two respective screws, which are disposed one on each side of the shaft, but there can be any number.
• the assembled jacket-securing arrangement 270 is rotatably mounted around gripper shaft 351.
• the jacket-securing arrangement must be able to freely rotate (in terms of the gripper shaft 351) although the range of its rotation may be otherwise limited by the confines of the cylinder gap 320.
• the members 272, 274 are each formed with part of a bearing surface to permit the clamping lever to rotate about the axis of the gripper shaft 351. In the non-limiting example of Fig. 9A and subsequent figures, each of the members 272, 274 has a part-cylindrical surface for engaging the circumference of the gripper shaft 351.
• the assembled jacket-securing arrangement 270 is disposed in an inter-gripper region, such as in any REGION(n) as discussed in connection with Fig. 6.
• the jacket-securing arrangement 270 can only be disposed in an inter-gripper region 353 because otherwise a gripper 350 or other equipment (e.g. , shaft bearing 269) will preclude such disposition.
• the jacket-securing arrangement also includes a magnet 280, such as a neodymium magnet.
• the magnet 280 in the example of Fig. 9 A, is fixedly attached to the first member 272, although in alternative embodiments the magnet 280 can be attached to another part of the clamping lever.
• the magnet 280 can be attached directly to a member of the jacket-securing arrangement 270 or, alternatively, it can be installed in a magnet holder (not shown) which is fixedly attached to the member.
• a magnet 280 may alternatively or additionally be secured to the wall of the recess and the clamping lever may be made of a ferromagnetic material. Such a configuration may be adopted in a situation where the material of the wall of the recess in the cylinder is not strongly ferromagnetic.
• the jacket assembly 270 cannot be mounted on a gripper shaft 351 when in the assembled state. Rather, it must be in an unassembled state.
• Figure 9C shows a jacket-securing arrangement 270 in a first unassembled state - the members 272, 274 are completely disassembled and are not connected in any way.
• Figure 9D shows a jacket-securing arrangement 270 in a second unassembled state according to an alternative embodiment - the members 272, 274 are connected by a linking arrangement 273.
• Linking arrangement 273 can comprise a hinge, as shown in Fig. 9D, or it can comprise any other mechanical arrangement, such as a cable, for connecting the two members in the unassembled state.
• Using a linking arrangement can be beneficial, for example, where the possibility of dropping one of the members into the cylinder gap during installation or removal of the jacket-securing arrangement 270 might be a concern.
• the jacket-securing arrangement of Fig. 9A in the assembled state (i.e.. rotatably mounted around the gripper shaft 351 and disposed in an inter gripper region 353), secures a tab 229 of jacket 225 to a surface of the cylinder gap 320.
• the magnet 280 holds the jacket-securing assembly 270 in place, by the force of its magnetic attraction to the surface of the cylinder gap at a first location 321;‘in place’ can mean, for example, that the jacket-securing assembly 270 is not easily rotatable when in this position.
• This magnetic force is effective to cause the securing of an upper portion 275 of first member 272 to the surface of the cylinder gap at a second location 322, with a portion of the jacket tab 229 being‘clamped’ or‘trapped’ between the upper portion 275 and the surface of the cylinder gap.
• the force of the magnetic attraction at the first location 321 causes the‘indirect’ [magnetic] securing of the jacket tab 229 at the second location 322.
• the magnetic securing provided by the jacket-securing arrangement encompasses the‘direct’ securing of the first magnet on a first part of the cylinder gap (e.g.
• a portion of the jacket of the impression cylinder to a second part of the cylinder gap (e.g. , at a second location 322), for instance by reversible, quick release, mechanical clamping.
• an adjustment mechanism 281 is provided to facilitate manual adjustment (e.g., tightening or loosening) of the connection between the first member 272 and the magnet 280.
• This can be a useful feature to have available when, for example, imperfections in the surface of the cylinder gap 320 at the first location are such that the magnet is not disposed at the optimal angle when the upper portion 275 contacts the tab 229 at the second location 322 during installation of the jacket-securing arrangement 270.
• the surface of the cylinder gap 320 at the second location 322 may be machined, while the surface at the first location 321 may be the result of a less precise casting process, the‘step’ between the two locations being one artefact of such a two-step manufacturing process.
• one or more additional elements can be fastened to a jacket tab 229 for improving the installation process on a cylinder 220 and for otherwise increasing the effectiveness of the use of jacket-securing arrangements 270.
• the jacket installation process can be made more efficient by lightly affixing the jacket tabs 225 to the cylinder gap surface, using sufficient adhesion to temporarily keep the tabs 229 in place long enough to complete the installation process.
• an affixing element 81 is caused to adhere to the cylinder facing side of a jacket tab.
• affixing element 81 comprises a small, thin magnet with sufficient force to hold a respective jacket tab 229 in place during installation - but which does not require undue force or special tooling for disconnecting the tab from the cylinder gap surface when the jacket 225 is eventually removed and the jacket-securing arrangement 270 is rotated out of the first rotated position.
• affixing element 81 comprises an adhesive tape or film, which can be a two-sided adhesive tape or film, for example a reusable tape or film.
• Friction pad 79 can be provided so as to increase a frictional resistance force between the upper portion 275 of first member 272 of jacket-securing arrangement 270, and the surface of the tab 229.
• Friction pad 79 can comprise a cloth, a rubber, a plastic or any combination of such materials that increases the frictional resistance and can help reduce possible centrifugal slippage of the tab 229 during operation of the printing system 100
• Any number of tabs 229 on a jacket 225, from zero to N (all the tabs) can be equipped with friction pads 79 and/or affixing elements 81.
• tabs 229 are equipped with one or both of a friction pad 79 and an affixing element 81, or even that all tabs 229 are equipped with one or both of a friction pad 79 and an affixing element 81.
• the magnet 280 can be attached elsewhere, for example to the upper portion 275, such that the magnet directly secures the jacket tab 229 to the surface of the cylinder gap 320 at the‘second’ (only) location 322.
• the magnet 280 is attached to, and at other times removed from, the surface of the cylinder gap 320 at the first location 321 by rotating the jacket-securing arrangement 270 around the gripper shaft 351.
• the jacket-securing arrangement is in a first rotated position where, as in Fig. 10A, the magnet is in place at the first location 321 on the surface of the cylinder gap 320, and the jacket tab 229 is secured by the upper portion 275 at the second location 322.
• the first rotation position is thus the‘jacket-securing position’.
• the rotation of the jacket-securing arrangement 270 to the first rotation position is in the direction indicated by arrow 2020. As shown in Fig.
• the jacket-securing arrangement 270 can comprise a second magnet 285 attached to a portion of the jacket-securing arrangement 270 displaced from the first magnet 280.
• the second magnet can be attached directly or, as shown in Fig. 11A by a bracket 287 that holds the second magnet 285 at a more favorable angle for its purpose.
• the jacket-securing arrangement 270 is shown in the second rotated position.
• the rotation of the jacket-securing arrangement 270 to the second rotation position is in the direction indicated by arrow 2030, and is opposite to the direction of rotation to the first rotated position which is indicated in Fig. 11A by arrow 2020.
• the second rotated position as shown in Fig.
• the first magnet is displaced from the first location 321 on the surface of the cylinder gap 320.
• a magnetic attraction between the second magnet 285 and a second surface portion 323 of the cylinder gap 320 holds the jacket-securing arrangement 270 in the second rotated position, the second surface portion 323 being therefore also referred to as the second position surface portion or as a third location of the gap surface.
• the second magnet 285 is not provided, and if necessary, other methods of preventing the magnet 280 from‘snapping back’ to its regular target of the first location 321 on the surface of the cylinder gap 320 can be used, such as providing a mechanical restraint.
• a preferred method for rotating a jacket-securing arrangement to the second rotated position is to apply a force to the second arm of the bell-crank clamping lever (e.g . , on the side of second member 274 distal from magnet 280) that will translate to sufficient moment to remove the magnet 280 from where it adheres magnetically to the first location 321 on the surface of the cylinder gap 320.
• a force F can be applied effectively to a force -receiving surface 277 of the jacket-securing arrangement 270.
• the force-receiving surface 277 in Fig. 12 is an upward-facing surface of a force-receiving portion 278 of the jacket- securing arrangement 270.
• the force-receiving portion 278 is provided so as to be diametrically opposite the first location 321 where the magnet 280 is disposed when in the first rotated position - or within +30° of being diametrically opposed, or within +15° of being diametrically opposite.
• the force F can be applied in a downward direction relative to the cylinder gap, meaning roughly parallel to the surface of the cylinder gap 320 at the first location 321.
• valleyly parallel we mean within 15° either way of being parallel, or within 30° either way of being parallel.
• the force-receiving surface at the time of applying the force F is roughly perpendicular to the surface of the cylinder gap 320 at the first location 321.
• the release of the jacket tabs 229 coincident with the release of the magnet 280 from the surface of the cylinder gap 320 is effectively accomplished by leveraging the rotatability of the jacket-securing arrangement 270 around the gripper shaft 351.
• applying a moderate force F to the force-receiving portion on the opposite side of the jacket-securing arrangement 270 i.e.. the side of the jacket-securing arrangement 270 that is on the opposite side of the gripper shaft 351 makes it possible to accomplish the release of the magnet 280 with less force than would be necessary to pull it directly off with a force applied at the first location 321.
• removing a jacket 225 from a cylinder 220 involves releasing multiple magnets 280 from the surface of the cylinder gap 320 and rotating multiple jacket-securing arrangements 270 away from the first rotated position.
• An elongated, rigid bar or bracket 369 can be provided to apply a force (e.g., F) at each of the force-receiving surfaces
• a method of releasing the jacket tabs 229 can be performed which includes using a bracket 369 to apply a force simultaneously to all of the force-receiving surfaces 277, but without simultaneous rotation of all of the plurality of jacket- securing arrangements 270. According to the method, a thickness of the force-receiving portion
• FIG. 14A a schematic illustration of a force-receiving portion 278 (of a jacket- securing arrangement 270) is shown with multiple possible thicknesses and corresponding possible dispositions (or versions) of the upward-facing force-receiving surface 277.
• Each force-receiving portion 278 can have a variable thickness along its length, but the variable thickness is nonetheless different in each of the thickness possibilities shown in Fig. 14A.
• the force-receiving portion 278 shown in all previous figures in this disclosure has the maximum thickness possibility of all the possibilities illustrated in Fig. 14A and includes the uppermost force-receiving surface 277A.
• the second-thickest possible force-receiving portion 278 in Fig. 14A includes force-receiving surface 277B.
• the third-thickest possible force receiving portion 278 in Fig. 14A includes force -receiving surface 277C, and so on until the thinnest possible force-receiving portion 278 of the possibilities illustrated in Fig. 14 includes force-receiving surface 277G.
• the efficacy of this solution can be understood from Figure 14B, which integrates the illustration of multiple force-receiving portion thicknesses of Fig. 14A with the elevation view of Fig. 12.
• jacket- securing arrangements 270 When disposed in the first rotated position, all of the jacket- securing arrangements 270 are parallel to each other: (a) respective magnets 280 are disposed against the surface of the cylinder gap 320 at respective first locations 321 and therefore are parallel to each other; and (b) the bottom or downward-facing surfaces of the respective force receiving portions 278 are also parallel to each other.
• the relative disposition of different upward-facing force-receiving surfaces 277A, 277B, etc. can be defined by rotation angles with respect to the gripper shaft 351.
• a force-receiving surface 277A is at a first rotation angle indicated by the arrow 2040A
• a force-receiving surface 277B is at a second rotation angle indicated by the arrow 2040B.
• Each possible receiving surface 277 can have a different corresponding rotation angle 2040.
• the rotational difference between the two consecutive rotation angles 2040A and 2040B can be, for example 1°.
• all pairs of respective rotation angles 2040 corresponding to consecutive thickness options are separated by substantially the same 1° angle. In other examples, the separation can involve larger or smaller angles of rotational differences, and not all angles of rotational differences between consecutive thickness options of force receiving portions need be the same.
• the interval between the‘first time’ and the‘second time’, or between the‘second time’ and the‘third time’ can be less than a second, less than half a second, or less than one tenth of one second.
• the total time elapsed between contacting the highest force receiving surface 277 (277A) and contacting the lowest force-receiving surface 277 e.g., 277G or 277F, or 277E, etc., depending on how many different thicknesses of force-receiving portions 278 are deployed
• the intervals are sufficient to distribute the work of applying forces F' among the different time intervals, and thereby allow the release of all of the respective magnets 280 from the surface of the cylinder gap 320 with a single downward force-application of bracket 369.
• no more than two jacket-securing arrangements 270 share the same force-receiving portion thickness.
• no more than three jacket-securing arrangements 270 share the same force-receiving portion thickness.
• jacket-securing arrangements 270 are arranged so that the distribution of force-receiving portion thicknesses is symmetrical.
• jacket-securing arrangements 270 with force-receiving surfaces 277A are placed as the outermost jacket-securing arrangements 270, i.e., closest to the opposite ends of the cylinder gap 320. Adjacent to them (inter-gripper region 353 closer to the center of the array of jacket-securing arrangements 270) are those with force-receiving surfaces 277B, and then those with force-receiving surfaces 277C, and so on.
• the bracket 369 can be positioned such that a protrusion (not shown) included near each end of the bracket 369 can be fitted to a matching receptacle (265 in Fig.
• the protrusion-receptacle fitting can be useful in firmly positioning the bracket for the application of the force that rotates the jacket-securing arrangements 270 away from the first rotated position and thereby releases the jacket tabs 229.
• a printing system 100 can be designed such that an impression cylinder 220 completes one rotation for every two ink-images transferred to substrate 231.
• Figure 15 illustrates an example of such a case, wherein tabs 229i of first jacket 225i are secured by first jacket-securing arrangements 270i in first cylinder gap 320i, and tabs 2292 of second jacket 2252 are secured by second jacket-securing arrangements 2702 in second cylinder gap 3202.
• a first trailing portion 227i of first j acket 225i is secured in second cylinder gap 3202
• a second trailing portion 2272 of second jacket 2252 is secured in first cylinder gap 320i.
• Figure 16 shows in greater detail (with the second jacket-securing arrangement 2702 removed from the drawing) the securing of first trailing portion 227i within second cylinder gap 3202.
• the trailing portion does not encounter grippers and grippers shafts and therefore can be simply secured to a surface of the cylinder gap without special arrangements.
• a trailing edge of the jacket can be inwardly turned to follow an undercut segment of the gap, the undercut wall being recessed with respect to the outer surface of the cylinder.
• the folded angle formed by the trailing edge and the jacket shall be of less than 90°.
• a trailing edge magnet holder 290 for applying and removing a trailing-portion magnet 223 (or a plurality of trailing-portion magnets 223) is provided for securing the first trailing portion 227i.
• a printing system 100 adapted to enable printing on both sides of a substrate 231 (perfecting) can include a second impression cylinder 520 for that purpose.
• a jacket 225 according to the various embodiments disclosed herein can be mounted on the perfecting cylinder 520 in the same manner as described for mounting on the‘simplex’ impression cylinder 220: a jacket-securing arrangement 270 rotatably mounted on a gripper shaft 351 in cylinder gap 620 magnetically secures a jacket tab 229 to a surface of the cylinder gap 620 using a magnet 280.
• the jacket-securing arrangement 270 of the perfecting cylinder 520 can be positioned with magnet 280 removed from the surface of the cylinder gap 620 (and jacket tab 229 released) by the use of second magnet 285 and its magnetic attraction to opposite cylinder gap surface 624.
• the arrangement of the second magnet 285 here can be different than the arrangement in the simplex cylinder (Fig. 1 IB) because of structural differences between the cylinder gaps. This minor difference does not change the underlying concept of using a second magnet 285 to hold the jacket-securing arrangement 270 in the second rotated position, e.g., for replacement of a jacket 225.
• a method for installing a jacket-securing arrangement 270 and a cylinder jacket 225 on a cylinder 220 (or 520).
• the method comprises: a) Step SOI assembling a plurality of jacket-securing arrangements 270, each jacket- securing arrangement 270 comprising (i) a magnet 280, (ii) a first member 272 holding the magnet, and (iii) a second member 274 that is reversibly attachable to the first member 272, such that each assembled jacket-securing arrangement 270 is disposed in a respective inter-gripper region 353 and rotatably mounted around the gripper shaft 351.
• Step S02 arranging, on the cylinder 220 (or 520), a jacket 225 having a plurality of tabs 229 extending therefrom, such that each of the tabs 229 is disposed in a corresponding inter-gripper region 353.
• Step S03 causing each of the jacket-securing arrangements 270 to rotate around the gripper shaft 351 to the first rotated position, so as to magnetically secure each of the jacket tabs 229 to a surface portion of the cylinder gap 320 (or 620).
• the method additionally comprises the following optional step: d) Step S04 when the assembled jacket-securing arrangements 270 are in the first rotated position, and the corresponding jacket tabs 229 are secured to the surface of the cylinder gap 320 (or 520), manually adjusting a connecting arrangement 281 between a magnet 280 and a respective jacket-securing arrangement 270 so as to improve the contact between the magnet 280 and the surface of the cylinder gap 320 (or 620) at a respective first location 321.
• a method for replacing a cylinder jacket 225 on a cylinder 220 (or 520) on which jacket-securing arrangements 270 are installed according to any of the embodiments disclosed herein.
• the method comprises:
• Step Sll applying a force F (or F) at a respective force-receiving surface 277 of each of the jacket-securing arrangements 270, so as to rotate the jacket-securing arrangements 270 to the second rotated position and thereby release the jacket tabs 229 from being magnetically secured to the surface of the cylinder gap 320 (or 620).
• Step S12 removing the used jacket 225 from the cylinder 220 (or 520).
• Step S13 arranging a replacement jacket 225 on the cylinder 220 (or 520), such that each of the tabs 229 is disposed in a corresponding inter-gripper region 353.
• Step S14 causing each of the jacket-securing arrangements 270 to rotate around the gripper shaft 351 to the first rotated position, so as to magnetically secure each of the tabs 229 of the replacement jacket 225 to the surface of the cylinder gap 320 (or 620).
• the terms“configured to”,“adapted to”,“operative to”,“suitable for”, “made to”, and“designed to” may be used interchangeably to indicate the ability or capability of an element or structure to perform its recited function.
• each of the verbs,“comprise”, “include” and“have”, and conjugates thereof, are used to indicate that the object or objects of the verb are not necessarily a complete listing of features, members, steps, components, elements or parts of the subject or subjects of the verb.
• the singular form“a”, “an” and“the” include plural references unless the context clearly dictates otherwise.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Feeding Of Articles By Means Other Than Belts Or Rollers (AREA)
• Ink Jet (AREA)
• Screen Printers (AREA)
• Supply, Installation And Extraction Of Printed Sheets Or Plates (AREA)

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• 2019
  • 2019-03-19 GB GB1903768.8A patent/GB2582333B/en not_active Expired - Fee Related
• 2020
  • 2020-03-18 US US17/435,694 patent/US12246528B2/en active Active
  • 2020-03-18 CN CN202080021180.5A patent/CN113646175B/zh active Active
  • 2020-03-18 WO PCT/IB2020/052448 patent/WO2020188491A1/en not_active Ceased
  • 2020-03-18 EP EP20720119.5A patent/EP3941749B1/en active Active
  • 2020-03-18 JP JP2021556610A patent/JP7581229B2/ja active Active
• 2025
  • 2025-01-14 US US19/020,330 patent/US20250144930A1/en active Pending

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