The present disclosure relates to printing on generally cylindrical objects. The term “generally cylindrical” is intended to refer to straight-sided three-dimensional objects, such as cans and tubes, having a uniform essentially circular or elliptical cross section.
In a wide variety of fields, it is desired to print an image onto the surface of generally cylindrical objects made of a variety of materials. Such processes are common in the packaging industry for a variety of containers from relatively rigid canisters made of metallic or plastics materials (such as food or beverage cans, aerosol cans, caulking paste tubes and the like) to relatively flexible containers (such as toothpaste tubes, yoghurt cups, margarine tubs, drinking glasses and the like), as well as for lids for such containers of solids or liquids.
In some cases, a cylindrical surface is produced by rolling and seam welding a flat sheet, and, in such cases, printing can be carried by conventional means on the surface while it is still flat. However, different printing techniques are required when the cylindrical surface is formed, for example, by deep drawing or extrusion and the ink image must be applied to a curved surface.
Printing systems are known for printing on cylindrical objects that are open at one end, such as cans that have yet to be closed and filled. The hollow objects may be passively fed to a printing apparatus by gravity or they may be mounted on mandrels of a system that advances the cans through an impression station. Typically, the mandrels rotate the cans around their longitudinal axis while ink is directly or indirectly deposited on their outer surface. In indirect offset printing systems, the rotating mandrels generally press the objects mounted thereon against an ink image bearing surface during their passage through the impression station to impress an ink image onto the cylindrical surface. To meet the needs of the industry, such systems are preferably high speed continuous decorating machines.
The printing apparatus has a transport turret 14 that carries around its circumference a plurality of cantilevered mandrels 16 mounted in a planetary manner around a center of rotation, each mandrel being dimensioned to fit within a respective one of the cans. Each mandrel may be mechanically rotated through gears, pulleys and the like, or may be directly driven by a motor, such as a servo motor. The effect of the gearing or servo motor, not shown, is to cause each mandrel 16 to spin about its own axis at approximately the same surface velocity as the surface of circumferentially spaced blanket pads 20 while being transported counter-clockwise along a circular path by the transport turret 14. The transport turret 14 in this way brings each can sequentially to an impression station at a nip region 18 where it rotates and rolls against one of several circumferentially spaced blanket pads 20 that are carried on the outer surface of a clockwise rotating impression drum 24. The blanket pads 20 are ink bearing pads that, during rotation of the impression drum 24, pass beneath a plurality of print heads 22 sequentially depositing parts of the ink image.
Each print head 22 is controlled to apply ink of a respective color to a respective region of each blanket pad. Ink application in such apparatus is traditionally performed by conventional means known in the field of offset printing, for instance using plates such as employed for flexographic printing. Digitally controlled application of inks by ink jetting techniques are also known, so that print heads 22 may encompass any such device suitable for either “mechanical printing” or “digital printing”. In this way, during a cycle of rotation of the impression drum 24, a multicolor ink image is built up on each blanket pad and at a nip region 18 of the impression station, the blanket pad 20 makes rolling contact with one of the cans 106 in order to impress the applied multicolor ink image onto its outer surface, the different colors typically residing in a registered manner in different regions of the blanket pad, so as to not unduly overlap.
The objects must be aligned with and conveyed to the blanket pads, so that the ink images can be transferred onto the surfaces of the objects in a controlled manner, which need not be detailed herein.
Such an apparatus may further comprise a pre-printing processing station 15 and/or a post-printing processing station 17, serving respectively to treat the cans before and after the impression station in any manner suitable and desirable for the particular printing process.
In the apparatus of
The present disclosure seeks to provide an improved design of the transport and transfer mechanisms in a system for printing on a cylindrical surface that inter alia overcomes certain disadvantages, which will be discussed in greater detail below.
In accordance with a first aspect of the invention, there is provided an apparatus for printing images on generally cylindrical objects, comprising:
In some embodiments, the impression platen is configured to apply a force directly to each object, by making rolling contact with a region of the surface of each object diametrically opposite a line of contact between the object and the imaging surface.
In alternative embodiments, the impression platen may be configured to contact the transport mechanism, so as to urge the mandrels on which the objects are supported towards the imaging surface.
The transport turret 14 in the printing apparatus of
In some embodiments, the mandrels carrying the objects that are advanced through the impression station are connected to one, or more, flexible endless drive member(s).
Because the drive member used to advance the mandrels through the impression station is not called upon to apply a force to urge the objects against the imaging surface, there is nothing to preclude the drive member from being a chain or a drive belt instead of a turret. This offers the advantage that the drive member may now form part of a conveyor transporting the objects through various other stations. Such stations may include a pre-treatment station, where, for example, a primer may be applied to the objects or a post-treatment, where, for example, a varnish may be applied to protect the ink image.
It has also been proposed to use as the imaging surface the continuous outer surface of an Intermediate Transfer Member (ITM) of an offset printing system in place of the individual blanket pads 20 of the impression drum 24 shown in
While the ITM 30 passes through the nip region 18 where it contacts the object to be printed or decorated, the ink image transfers from the outer (e.g., hydrophobic) surface of the ITM 30 to the objects 106 carried by the mandrels 16, and the surface of the ITM can then optionally be cleaned or otherwise treated at a cleaning/treatment station 36 before returning to the imaging station 32 to commence a new cycle. The apparatus of
In some embodiments of the present disclosure, the imaging surface upon which an ink image can be deposited is that of an endless ITM of an offset printing system.
The force acting to apply pressure at the nip may, in some embodiments, result from the tension in the ITM. A sufficient tension of the ITM in the region overlapping the impression platen can be maintained by a variety of techniques to be detailed hereinbelow. Alternatively, the inner surface of the ITM may rest on a support surface which resists the force applied by the impression platen via the objects or which applies a force to the inner surface, urging the ITM towards the impression platen. As used herein the term “support surface” encompasses any area of a solid or flexible body able to urge or maintain the ITM at a distance from the impression platen suited to ensure rolling contact of the objects passing therebetween.
The support surface may be that of a solid object contoured to match the surface of the impression platen. By “contoured to match”, it is meant that the distance between the impression platen and the support surface corresponds to the width dimension of the objects as they roll through the nip region. For circular objects, the width dimension is the constant diameter of the objects, whereas for elliptical objects it is the dimension as measured along a line passing through the intersection point of the major and minor axes of the ellipse and the points of contact of the objects with the impression platen and the support surface, as they roll without sliding through the nip region.
In order to maintain rolling contact between the objects and the ITM, it is necessary for the speed of the drive member transporting the mandrels through the nip region to move at half the speed of the ITM.
While ITMs having a relatively short circumference can have a seamless outer surface, longer ITMs are generally formed from a blanket strip of which the ends are joined to one another at a seam to form of a continuous loop. An ITM, which is also sometimes termed a transfer belt, may include more than one seam, depending on the numbers of blanket strips being attached to obtain any desired length.
It is not desirable to use a region of the ITM bearing a seam for printing, if good results are to be achieved, as the seam imperfections may create image defects. Because the speed of the ITM is exactly related to the speed of the drive member of the mandrels, and because the separation of the mandrels is predetermined, it is possible, by appropriate selection of the total length of the ITM, to ensure that only the same predetermined regions of the ITM are used for printing. This enables any seam region of the ITM to be designated as a no-print area and printing defects can be avoided by preventing objects from being loaded onto mandrels at locations that would coincide in the nip region with seam regions of the ITM.
Other regions of the ITM may be designated no-print regions. For example, if the ITM develops a local defect during use, the apparatus may be programmed not to print in the region of the defect instead of replacing the entire ITM.
Because of the presence of no-print regions on the ITM, in some embodiments, the printing apparatus may comprise a skip-feed mechanism to prevent objects from passing through the nip region if they would coincide with a no-print region.
While it would be possible merely to avoid loading objects onto selected mandrels, it is preferable for the mandrels to be removably connected to their drive member, so that a mandrel may be entirely removed from any location on the drive member that is synchronized with a no-print region of the ITM. This removal of the mandrel from its shaft, or even the removal of the shaft itself, is advantageous in printing processes where the ITM is pre-treated with a material which may transfer to the mandrel surface. Removal of mandrels is, for example, desired if the ITM is chemically conditioned.
A mechanism that may be used for loading and unloading of objects onto the mandrels may comprise an endless conveyor on which cradles are mounted at the same pitch as the mandrels. The conveyor has a transfer run that extends parallel to the drive member carrying the mandrels and the conveyor is timed so that the cradles and the mandrels remain correctly aligned with one another over the entire length of the transfer run. Objects from a vertical stack are dropped individually into each cradle and a force is applied as the mandrels and cradles travel side by side to transfer the objects from the cradles to the mandrels.
As a printing apparatus is preferably adapted to print on a variety of generally cylindrical objects that may have different diameters, the shape of the cradles can be varied for each diameter and/or the conveyer can be lowered or heightened with respect to the drive member, ensuring that the longitudinal axis of the object on the cradle is aligned to be co-axial with the shaft of the mandrel. The force effecting the transfer of the objects from the cradles to the mandrels or back may be applied by a stationary ramp. Alternatively, or additionally, an air knife, or other source of air pressure, may act to push the cradled objects towards the mandrels and suction may be applied by the mandrels to pull the objects onto them. To this end, the mandrels may be hollow and connected to a source of negative pressure as they pass along the transfer run. A reversed air pressure can be applied for unloading the printed objects.
The force effecting the transfer of the objects from the cradles to the mandrels may be maintained once the object is mounted on the mandrel for the duration of the impression, serving then as a locking mechanism. For instance, suction of the object on a hollow mandrel may maintain the object in position with respect to the shaft of the mandrel, allowing it to rotate during its passage between the impression platen and the support surface (e.g., tensioned ITM or solid body). Alternative, or additional, mechanisms may be used to lock the object in position once mounted on the mandrel. By way of non-limiting examples, the locking mechanisms may include expansion rings or sleeves and for ferric objects may involve a magnet. Alternatively, the objects may be held in place on the mandrels during the image transfer process simply by a guard rail preventing them from sliding out of position.
In a loading mechanism of this design, a skip-feed may be achieved by operation of a gate located at the bottom of the stack from which objects are dropped onto the cradles. Such a gate is opened when an object is to be dropped onto a cradle of the conveyor and is then closed to await the arrival of the next cradle onto which an object is to be loaded. If a cradle is one aligned with a location on the drive member where no printing is to take place, then the gate is merely kept closed during the passage of that cradle.
It is possible to identify cradles where no printing is to take place merely by counting, as the pattern of no-print regions on the ITM will repeat cyclically. Thus, the gate may be operated to follow a preset program. Alternatively, if mandrels are removed from the drive member at locations where no printing is to take place, then the sensed absence of a mandrel may serve to generate a signal to close the gate.
The ink image can be deposited on the outer or imaging surface of the ITM by any suitable printing process whether digital or not. Printing processes that are commonly used to form an ink image directly on the end substrate (e.g., paper or plastic foils), may be adapted to apply the ink image instead on an ITM. Such printing processes may include lithography, flexography, gravure and screen printing, which are well suited to long runs of identical images. In such processes, the ink image can at least partially transfer to the outer surface of the objects, reapplication of an identical ink image (reinking) being performed substantially at the same location on the ITM in a subsequent cycle.
Advantageously, the ink image is deposited by digital printing processes, such as ink jetting, xerographic printing or other electrophotographic printing methods, more adapted for shorter runs of changing images. The ink image when digitally deposited on the imaging surface of the ITM could even allow customization of individual objects, if desired. In such processes, because images may differ from cycle to cycle, the ink image should preferably transfer substantially fully to the object. While partial transfer may be tolerated, such would impose a duty to sufficiently clean the imaging surface before returning the ITM to the imaging station for the following cycle.
After an ink image has been impressed onto the first half of an object, it will come into rolling contact with the impression platen. As the ink image at this stage may retain some of its tackiness, it is desirable to form the surface of the impression platen of a low surface energy material, to which the tacky ink will not adhere. Non-limiting examples of such low surface energy materials (e.g., having a surface energy of 50, 40, 30 or 20 millinewtons per meter (mN/m) or less) are silicone, fluoro-silicone, ethylene-tetrafluoroethylene and polytetra-fluoroethylene (PTFE).
In some embodiments, the ITM passes in the nip region over a cylinder in rolling contact with the ITM and the impression platen is concave.
In alternative embodiments of the invention, the impression platen may be flat or convex.
If the impression platen is convex, the tension in the ITM may suffice to ensure rolling contact with the objects as they pass through the nip region. With metal and plastics objects, that have a smooth surface, and that may have been pre-treated to improve their bonding to the ink image, a relatively small force may suffice to permit transfer of the ink images from the ITM to the objects. If the ITM tension is insufficient, an additional force may be applied to the inner surface of the ITM by a sponge roller as it passed through the nip region.
If the impression platen is flat, the inner surface of the ITM may rest against a flat support surface. The support surface in such case may be made of, or coated with a low-friction material, such as PTFE (e.g., Teflon®).
To reduce friction between the ITM and the support surface, it is possible to use as a support surface a tensioned run of a belt that is driven at the same speed as the ITM. If desired, to avoid even small deflection of the ITM during passage through the nip region, a stationary body may be provided in contact with the opposite side of the run of the belt that contacts the ITM.
The drive member serving to transport the mandrels through the nip region may suitably be constructed as a belt, such as a toothed belt, or as a chain formed of links that are pivotably connected to one another.
In some embodiments, the flexible drive member carries through the impression station evenly spaced rotatable mandrels. Mandrels aligned to one another in the print direction on a same side of the drive member can be viewed as a “column” of mandrels. In some embodiments, the flexible drive member carries a single column of mandrel, for single-sided mounting of generally cylindrical objects. Alternatively, to avoid the weight of the mandrels applying a torque to the drive member about an axis parallel to its direction of movement, it is desirable to dispose the mandrels symmetrically on opposite sides of the drive member. In this case, the mandrels are rotatably coupled to the flexible drive member as two parallel columns of mandrels, pairs of two mandrels in the adjacent columns of a common drive member being typically aligned with one another along their longitudinal axis. Mandrels aligned “side-by-side” to one another on each side of the drive member in the direction traverse to the print direction can be viewed as a “row” of mandrels.
As mentioned, it may be advantageous to be able to easily remove rows of mandrels to avoid no-print regions. The ability to easily modify the sequence of the mandrels on the drive member is advantageous in additional circumstances, for instance when the size and/or shape of the objects to be printed upon is changed from one print job to another. Such adaptability of the drive member may preclude the need to hold a variety of drive members each adapted for a different type (size and shape) of objects.
In some embodiments, the mandrel is attached to the drive member via an independent mandrel shaft. The mandrel shaft is rotatably attached to the drive member and the mandrel body (hollow or not) is fixedly attached to its shaft. Preferably, the mandrel shafts may be capable of supporting a number of different mandrel bodies, allowing printing on at least the same number of different objects mountable on each of the mandrel bodies.
While the pitch between mandrels can be modified according to the diameter of the objects to be mounted thereon, the pitch should correspond to at least about half the circumference of the object. The drive member can alternatively be suited for printing on the largest objects available at a decorating plan, in which case the replacement of the mandrel body with smaller mandrels without reducing the maximal pitch only increases the non-image gaps between the ink images on the ITM.
If the drive member is in the form of a chain, it is desirable for the axle of each mandrel to be aligned with one of the pivot pins connecting two links of the chain. In this way, even in the case of very small diameter mandrels, a single impression platen can be employed for each pair of mandrels without the chain interfering with the impression platen.
As an ITM may be considerably wider than the axial length of the objects (e.g., at least twice, at least three-times, or at least four-times the axial length of the object), it is possible for several drive members each carrying single-side columns of mandrels/objects or side-by-side pairs of objects to interact at the same time with a common ITM. For instance, the transport mechanism may consist of a) one drive member carrying two columns of mandrels side-by-side, or two drive members each carrying to the impression station a single column of mandrels, hence allowing concomitant printing on a row of mandrels mounted by two generally cylindrical objects; b) two drive members each carrying two column of mandrels side-by-side, hence allowing printing on four objects at a time in a row; or c) two drive members one carrying a single column of mandrels, the other supporting two such columns, hence allowing synchronous printing on three objects in a row of mandrels, and so on. Alternatively, several drive members may interact with the same ITM at stations staggered along the direction of travel of the ITM.
The number of flexible drive members in a transport mechanism, as well as the number of columns of mandrels each such drive would support, depends on the width of the imaging surface and the length of each cylindrical object to be mounted.
According to a second aspect of the invention, there is provided a method of printing on the outer surfaces of generally cylindrical objects, which method comprises:
In some embodiments of the printing method, the force is directly applied to each object by the impression platen, by making rolling contact with a region of the surface of each object diametrically opposite a line of contact between the object and the imaging surface.
In alternative embodiments of the printing method, the force is indirectly applied to each object by the impression platen, the impression platen alternatively contacting the transport mechanism so as to urge the mandrels supporting the objects towards the imaging surface.
According to a further aspect of the invention, there is provided an apparatus for printing on three-dimensional objects, having a printing station and a conveyor for transporting objects through the printing station, wherein the conveyor comprises mandrels connected to an endless drive member, a loading station at which objects are mounted onto the mandrels prior to passage through the printing station and an unloading station for removing the objects from the mandrels after passage through the printing station, wherein operation of the printing station is capable of temporary interruption and the endless drive member of the conveyor is configured to operate continuously, including times when the printing station is inoperative, and wherein the loading station includes a device for inhibiting loading of objects onto mandrels that will pass through the printing station at times when the printing station is inoperative.
In one embodiment, the mandrels are rotatably connected to an endless drive member of the conveyor for transporting the three-dimensional objects to be mounted thereon.
Some embodiments of the disclosure will now be described further, by way of example, with reference to the accompanying figures, where like reference numerals or characters indicate corresponding or like components. The description, together with the figures, makes apparent to a person having ordinary skill in the art how some embodiments of the disclosure may be practiced. The figures are for the purpose of illustrative discussion and no attempt is made to show structural details of an embodiment in more detail than is necessary for a fundamental understanding of the disclosure. For the sake of clarity and convenience of presentation, some objects depicted in the figures are not necessarily shown to scale.
In the Figures:
Nip Regions, ITM Support Surfaces and Impression Platens
As in the apparatus shown in
The contact between the objects 106 and the impression platen 124 causes the objects and their mandrels to rotate such that the objects 106 make rolling contact with the impression platen 124. For rolling contact between the objects 106 and the stationary platen 124, contact with the platen imparts an angular acceleration to the objects, causing them to spin with an angular velocity co, which is such that ω,r=v, where r is the radius of the objects and v is equal to the velocity of drive member 120. For the opposite side of the objects 106 to make rolling contact with the ITM 130, the latter must move with a velocity ω,r+v, that is to say at twice the speed of the drive member 120.
As the drive member 120 is flexible in the plane of
After the objects have rotated within the nip region through 180°, ink will reside on the surface of the objects in contact with the impression platen 124 and, as the ink may still be tacky, it is desirable for the impression platen 124 to have a low surface energy surface to which the ink will not adhere. Non-limiting examples of such low surface energy materials are silicone, fluorosilicone, ethylene-tetrafluoroethylene and poly-tetrafluoroethylene.
In the embodiment of
The embodiments of
In the embodiment of
The embodiments shown in
It will be noted in all six of the embodiments shown in
The embodiment of
In the embodiment of
The embodiment of
Mandrels Drive Members
In the embodiment of
The embodiments shown in
Skip-Feed Mechanism
As mentioned, an ITM suitable for transferring ink images to the outer surfaces of generally cylindrical objects according to the present teachings can be formed of one or more elongated blanket strips. The ends of the strip can be attached to one another by soldering, gluing, taping (e.g., using silicone adhesive strips, Kapton® tape, RTV liquid adhesives or PTFE thermoplastic adhesives with a connective strip overlapping both edges of the strip), or any other method commonly known. Any method of joining the ends of the blanket strip to form a transfer belt may cause a discontinuity, referred to herein as a seam.
The seam can be of different types. In particular, the edges may overlap one another or a patch may be applied to overlie the two ends. In either case, the seam may be subsequently processed, such as by grinding, to reduce its thickness to obtain an ITM having substantially the same thickness along the entire loop. Still the presence of one or more seams in an ITM may affect the print quality of an ink image which may span them. Therefore, in some embodiments, the printing process can be adapted to avoid applying an ink image in an area of the ITM including a seam. The feeding of the objects being printed upon needs to be accordingly discontinued, so that objects are transported through the impression station only synchronously with actual presence of ink images on the image bearing surface. An exemplary method (and device) to achieve this effect, referred to herein as “skip-feed”, will now be described by reference to
Each mandrel 816, 818 is fitted to the shaft 814 so that it can be pulled on and off simply and yet retained securely when in position. Retention of each mandrel is achieved by the magnet 1216 and/or by a spring-biased detent 1220 located in the shaft 814 adjacent the bearing 1218a proximal to the drive member. Such mounting allows the mandrels 816, 818 to be easily and quickly replaced by smaller ones when printing on smaller objects and enables individual mandrels to be removed when they synchronize with a no-print region of the ITM.
While a magnet has been proposed in the above with reference to
The way in which objects are loaded onto, and unloaded from, the mandrels will now be explained by reference to
As the cradles 1416, 1418 pass under their respective stacks 1430, 1432, objects drop, one at a time, into each cradle aligned with a mandrel. Whether or not an object 106 is allowed to drop out of a stack is determined by an interposer 1510 shown in
The interposer can 1510 be constructed in a variety of ways. In its simplest form, it may operate purely mechanically and take the form of a pivotable shaft having at one end a finger obstructing the descent of objects 106 from a stack and at the other end a sensing lever that rides on the mandrels. If a mandrel is present, then the sensing lever rotates the shaft to displace the finger lying in the path of the falling objects, whereas when no mandrel is present, the finger at the opposite end of the shaft prevents loading of an object onto the associated cradle.
In an alternative embodiment, the interposer may operate electrically and take the form of a solenoid operating a gate at the bottom of each stack. The solenoid may receive signals to close the gate upon detection of the absence of a mandrel by an associated electrical sensor. Alternatively, a pre-programmed digital processor which controls the application of ink images to the ITM may send signals to the interposer 1510 to prevent loading of object at positions that synchronize with no-print regions of the ITM.
The transfer of objects from the cradles 1416, 1418, to the mandrels 816, 818 can be performed mechanically, most simply by a stationary ramp acting on the closed end of the objects 106. However, in some embodiments shown in
To unload the objects from the mandrels, as depicted in
A Printing Apparatus
Referring now to
The objects on which printing is to take place are supplied in the illustrated embodiment from two pairs of stacks, 1830 and 1832, to two loading stations designated 1834a and 1834b, each of which is as previously described by reference to
After an ink image has been impressed on the objects, they may optionally pass again through a pre-treatment station 1842, where the objects may be subjected to a flame, a corona or plasma to prepare them for a varnish coating that can be applied at a varnishing station 1844. After the varnish, if applied, has been dried or otherwise cured such as, for example, by UV exposure or e-beam radiation in drying/curing station 1846, the paths of the two drive members carrying the mandrels once again diverge to take each drive member through a respective one of two unloading stations 1848a and 1848b at which the objects are sent on to further processing stations of the production line. In a production line for beverage cans, the objects may, for example, be internally coated or subsequently have their shape modified, and they may be filled with a beverage before a cap is secured to them to seal their contents.
Drying station 1840 and 1846 may also serve as heating stations for the mandrels and the objects to ensure that the surfaces of the objects enter the impression station at an elevated temperature which, in some embodiments, may be desirable to help ensure complete image transfer. Such pre-heating of the mandrels may also be accomplished by the addition of heaters or heating ovens at any location in the mandrel path, as, in some embodiments, the heat capacity of the mandrels enables them to heat the objects and maintain their elevated temperature even when not continuously exposed to external heat sources. Though any temperature above room temperature may be desirable, preferred mandrel temperatures may be between 30° C. and 100° C.
It will be seen that in
As has previously been explained, the speed of the ITM 1812 needs to be twice that of drive members of the mandrels. However, minor adjustments may be made to the speed of the ITM 1812 or of the drive members to ensure correct synchronization with the objects. Such adjustments to the synchronization are necessary as each of the ITM 1812 and the drive members has a degree of elasticity which requires slight periodic compensation to ensure that the ink images and the objects meet one another in register at the impression station when transfer is effected.
Furthermore, as has previously been mentioned, it is necessary for the length of the ITM 1812 to be a whole number multiple of the pitch between the objects. Since the ITM 1812 is somewhat elastic, tensioning of the ITM 1812 can be used to make minor adjustments to its length. It is for this reason that the ITM 1812 in
While the above-described skip-feeding mechanism for three-dimensional objects has been described in the context of a printing system according to the present teachings, wherein ink images are indirectly applied to the outer surface of generally cylindrical objects, this should not be construed as limiting. Moreover, while the presence of a seam on the ITM could be one reason to desire punctually discontinuing the mounting of objects on mandrels, other motives may exist, for instance, avoiding different types of defects on the ITM or on the objects to be printed upon.
Though not shown in
A skilled person will readily appreciate that the same principles of skip-feeding can be implemented in other printing systems, wherein the objects may have different shapes and/or wherein the ink image may be directly applied (e.g., by ink-jetting suitable ink compositions towards the object outer surface) instead of by contacting an ITM.
In all the embodiments described above, the objects are directly urged against the ITM at the nip by means of a stationary impression platen in contact with the objects on their opposite side to that in contact with the ITM. However, it is possible to avoid the impression platen coming into contact with the printing surface, if it is instead used to apply a force, via the transport mechanism, to the mandrels. Such embodiment is shown in
Additional Printing Stations
It is understood that in addition to the transport mechanism and the impression station wherein ink images are impressed on the surface of the object using an impression platen as above-mentioned, a printing apparatus as herein disclosed may further comprise inter alia a conditioning station and/or a cleaning station to respectively treat (e.g., by physical or chemical means) and/or clean the intermediate transfer member (such as illustrated by 36 in
The printing system may additionally, or alternatively, comprise stations wherein the object is processed. By way of non-limiting examples, the printing system may include a forming station where the object can be formed into a generally cylindrical object optionally including a lid at one end, a shaping station where surfaces of the object can be embossed or otherwise modified to include a functional or decorative pattern; a washing station where the object can be degreased or etched (e.g., ahead of printing), a drying station where a wet object can be dried (ahead of and/or following printing), a priming station where a priming composition or treatment (e.g., corona) can be applied to the outer surface of the object prior to printing (e.g., to further the adherence of the ink image to the object), a heating station or a cooling station to modify the object temperature along its path, a curing station (e.g., to cure an ink image transferred to the object), a coating station (e.g., to coat the transferred ink image with a protective or decorative varnish and/or to coat the interior of the object with a lining) and any other finishing station for further processing the printed objects. Any such station located upstream of the impression region can be termed a pre-processing station and any such station located downstream of the impression region can be termed a post-processing station. Such stations are schematically illustrated in
If desired the printing systems of the present disclosure can be connected in-line with a downstream filling system, wherein the printed objects can be filled with their intended content and lids thereafter attached (e.g., seamed by welding) to the filled bodies to seal the contents. All such stations known in the fields of printing and packaging need not be considered in detail in the present context.
The interested reader is referred to the following literature for non-limiting examples further illustrating how to implement the present invention and its various embodiments.
U.S. Pat. No. 5,893,016 describes an apparatus for printing images on generally cylindrical objects such as cans, including an image bearing surface having an image thereon and having an impression guide which is generally parallel to and spaced from the image bearing surface, which guide supports the cylindrical objects in rolling contact with the image bearing surface, whereby images are transferred from the image bearing surface to surfaces of the cylindrical objects in contact therewith. In U.S. Pat. No. 5,893,016, the objects are not supported on mandrels and the apparatus is not therefore well suited to printing on cans before they are filled and sealed. Furthermore, the articles are not advanced by a drive member through the printing station, relying instead first on gravity then on friction with the image bearing surface, and there is nothing to prevent the articles from skewing, prior to or during their passage through the printing station.
Printing sub-systems suitable for the apparatuses according to the present teachings are known to the skilled person and need not be detailed herein. Exemplary sub-systems which may be used, in some embodiments, are further detailed in WO 2017/208145 and WO 2017/208146, wherein, as opposed to the present invention, the objects are mounted on mandrels attached to a rigid support, the ink images being transferred in absence of an impression platen.
Consumables suitable for printing methods and apparatuses according to the present teachings include, in addition to the generally cylindrical objects being printed on, at least one of a) ink compositions, b) intermediate transfer members (e.g., continuous belts with or without a seam), and optionally c) conditioning liquids (e.g., for pre-treating the transfer members ahead of ink application), d) cleaning or washing liquids (e.g., for removing ink residuals from transfer members or degreasing the objects), e) priming liquids (e.g., for pre-coating the objects prior to printing), f) coating liquids (e.g., for applying an overcoat covering the ink image on the printed object), g) lining liquids (e.g., for applying a coat to the interior of the object); and h) like compositions readily appreciated by a person skilled in the art of printing.
Such consumables are selected and adapted to any desired particular configuration and operation of the printing method and apparatus. Moreover, the consumables are compatible with one another. For instance, if, during the printing process, the image bearing surface of the ITM is to be exposed to elevated temperature, it should be heat resistant at least to the applied temperature; if the transfer member is a tensioned belt, it should have mechanical resistance at least to the applied tension; if the transfer member is displaced, it should include, on the side opposite the surface upon which ink is deposited, a layer providing suitable friction or lack thereof with underneath guiding systems; and any such consideration readily appreciated by a person skilled in printing allowing use of the consumable under the operating conditions.
Similarly, from a chemical standpoint, the ink compositions need first to be compatible with the intermediate transfer member and/or with a conditioning liquid (if present). They also need to be adapted to the surface of the object the inks are printed on, and/or to be compatible with a priming compound and/or with a coating compound (if any pre- or post-applied to the object). Fundamentally, a material or a chemical composition is compatible with another if it does not prevent its activity or does not reduce it to an extent that would significantly affect the intended purpose. For instance, the ink compositions would not be compatible if, among other things, they swell the imaging surface of the ITM or otherwise distort its characteristics; if they are unable to at least partially transfer from the image bearing outer surface and/or attach to the surface of the object, whether or not pre-coated; if they are unable to attach an overcoat; if they resist cleaning of the printing system and have any like undesired effect. As readily understood, this principle of chemical compatibility of any consumable used herein with any other consumable should preferably guide the selection of all materials necessary for the compositions to be used in a printing system as disclosed herein.
Consumables suitable for printing methods and apparatuses according to the present teachings are known to the skilled person and need not be detailed herein. Exemplary consumables which may be used, in some embodiments, are further detailed in WO 2013/132418 and WO 2017/208152.
Ink compositions suitable for printing methods and apparatuses according to the present teachings are known to the skilled person and need not be detailed herein. Exemplary ink compositions which may be used, in some embodiments, are further detailed in WO 2013/132339, WO 2015/036812 and WO 2015/036865.
Intermediate transfer members suitable for printing methods and apparatuses according to the present teachings are known to the skilled person and need not be detailed herein. Exemplary transfer members which may be used or prepared, in some embodiments, are further detailed in WO 2013/132432, WO 2013/132438, WO 2017/208144 and WO 2017/208155.
Conditioning liquids suitable for printing methods and apparatuses according to the present teachings are known to the skilled person and need not be detailed herein. Exemplary conditioning liquids which may be used, in some embodiments, are further detailed in WO 2013/132339, WO 2015/036864, WO 2015/036960 and WO 2017/208246.
It is appreciated that certain features of the disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination or as suitable in any other described embodiment of the disclosure. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.
Although the present disclosure has been described with respect to various specific embodiments presented herein for the sake of illustration only, such specifically disclosed embodiments should not be considered limiting. Many other alternatives, modifications and variations of such embodiments will occur to those skilled in the art based upon Applicant's disclosure herein. Accordingly, it is intended to embrace all such alternatives, modifications and variations and to be bound only by the spirit and scope of the disclosure and any change which come within their meaning and range of equivalency.
The word “exemplary” is used herein to mean “serving as an example, instance or illustration”. Any example, embodiment, case, instance, or figure/illustration of certain feature(s) described as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments and/or to exclude the incorporation of one or more features from other embodiments. Furthermore, a feature which is described as preferred or advantageous in some embodiments, may not necessarily be preferred or advantageous in other embodiments.
As used herein, in the description and claims of the present disclosure, 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.
As used herein, the singular form “a”, “an” and “the” include plural references and mean “at least one” or “one or more” unless the context clearly dictates otherwise. At least one of A and B is intended to mean either A or B, and may mean, in some embodiments, A and B.
Unless otherwise stated, the use of the expression “and/or” between the last two members of a list of options for selection indicates that a selection of one or more of the listed options is appropriate and may be made.
As used herein, unless otherwise stated, adjectives such as “substantially” and “about” that modify a condition or relationship characteristic of a feature or features of an embodiment of the present technology, are to be understood to mean that the condition or characteristic is defined to within tolerances that are acceptable for operation of the embodiment for an application for which it is intended, or within variations expected from the measurement being performed and/or from the measuring instrument being used. When the term “about” precedes a numerical value, it is intended to indicate +/−15%, or +/−10%, or even only +/−5%, and in some instances the precise value. Furthermore, unless otherwise stated, the terms (e.g., numbers) used in an embodiment of the presently disclosed subject matter, even without such adjectives, should be construed as having tolerances which may depart from the precise meaning of the relevant term but would enable the embodiment or a relevant portion thereof to operate and function as described, and/or as understood by a person skilled in the art.
Positional or motional terms such as “upper”, “lower”, “right”, “left”, “bottom”, “below”, “lowered”, “low”, “top”, “above”, “elevated”, “high”, “vertical”, “horizontal”, “backward”, “forward”, “upstream” and “downstream”, as well as grammatical variations thereof, may be used herein for exemplary purposes only, to illustrate the relative positioning, placement or displacement of certain components, to indicate a first and a second component in present illustrations or to do both. Such terms do not necessarily indicate that, for example, a “bottom” component is below a “top” component, as such directions, components or both may be flipped, rotated, moved in space, placed in a diagonal orientation or position, placed horizontally or vertically, or similarly modified.
To the extent necessary to understand or complete the disclosure of the present invention, all publications, patents, and patent applications mentioned herein, including in particular the applications of the Applicant or the Inventor, are expressly incorporated by reference in their entirety for all purposes as is fully set forth herein. Citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the disclosure.
Certain marks referenced herein may be common law or registered trademarks of third parties. Use of these marks is by way of example and shall not be construed as descriptive or limit the scope of this disclosure to material associated only with such marks.
Number | Date | Country | Kind |
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1814882.5 | Sep 2018 | GB | national |
1907890.6 | Jun 2019 | GB | national |
This application is a Divisional of U.S. patent application Ser. No. 18/053,428, filed on Nov. 8, 2022, which is a Continuation of U.S. patent application Ser. No. 17/199,487, filed on Mar. 12, 2021, now issued as U.S. Pat. No. 11,541,652, which is a Continuation-in-Part (CIP) of International Application No. PCT/IB2019/057474, filed on Sep. 5, 2019, which claims priority to Great Britain Application Nos. GB 1814882.5, filed on Sep. 13, 2018, and GB 1907890.6, filed on Jun. 3, 2019. The entire disclosures of all the afore-mentioned applications are incorporated by reference herein for all purposes as if fully set forth herein.
Number | Date | Country | |
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Parent | 18053428 | Nov 2022 | US |
Child | 18424809 | US |
Number | Date | Country | |
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Parent | 17199487 | Mar 2021 | US |
Child | 18053428 | US |
Number | Date | Country | |
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Parent | PCT/IB2019/057474 | Sep 2019 | US |
Child | 17199487 | US |