Abstract:
A digital cliché pad printing system includes a conveyor for conveying a substantially non-elastic support medium, a material deposition jetting device for depositing a curable material onto the support in a desired pattern, the desired pattern having at least one void space, means for curing the material in the desired pattern, the cured material defining a cliché having a top surface, an ink delivery system for depositing ink in the at least one void space and for wiping ink from the top surface and a pad configured to contact the cliché to transfer ink from the void space to the pad the pad also configured to move into contact with an object to which the ink is transferred. A digital cliché media and method are also disclosed.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of priority of Provisional U.S. Patent Application Ser. No. 61/144,329, filed Jan. 13, 2009, entitled “DIGITAL CLICHE PAD PRINTING SYSTEM AND METHOD”. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to pad printers. More particularly, the present invention relates to a digital cliché pad printing system and method. 
         [0003]    Pad printing systems are used to apply high quality print, e.g. indicia. Pad printing systems use a deformable pad which receives ink, transferred as an image, from a cliché plate. The plate has an etching or engraving of the indicia formed therein. The image is transferred from the pad to the item onto which the indicia is applied. 
         [0004]    These systems work well to produce high quality image transfer and for transferring images onto flat, as well as textured and non-planar surfaces. One drawback to the pad printing method is that cliché plates are expensive to fabricate, e.g., prepare, etch, and mount. As such, short run or single run printing is cost prohibitive using a pad printing method. 
         [0005]    Digital systems (e.g., laser or ink jet printing) are often used for short run or single run printing due to the flexibility of these systems. These methods lend themselves well to short run and single run printing because printing commands such as image shapes are purely machine controlled. Accordingly, much lower costs are incurred in changing over the image to be printed or transferred. 
         [0006]    It has been found that digital printing is however, limited in practical application to symmetrical shapes (e.g., spheres, cones, cylinders) or to flat or near-flat applications that allow the print head to remain within a narrow stand-off distance from the surface of the object (typically within a distance of about 0.5 to about 2.5 mm) 
         [0007]    Other solutions to enable the flexibility of digital printing in a pad system include directly jetting ink onto the printing pads which is then transferred onto the object surface. It has however been found that inks that “jet” are not well suited for pad transfer, and often smudge or smear resulting in unacceptable image transfer. 
         [0008]    Accordingly, there is a need for a digital cliché pad printing system and method. Desirably, such a system and method permit the use of a cliché in single run and short run printing applications. More desirably, such a system and method provide high quality image transfer without the costs associated with conventional cliché preparation. 
       SUMMARY OF THE INVENTION 
       [0009]    A digital cliché pad printing system includes a conveyor for conveying a substantially non-elastic support member, a fluid jetting device for jetting a curable fluid onto the support in a desired pattern and means for curing the fluid in the desired pattern. The pattern has at least one void space and the cured fluid defines a cliché having a top surface. 
         [0010]    An ink delivery system deposits ink in the at least one void space and wipes ink from the top surface of the cliché. A printing pad is configured to contact the cliché and transfer ink from the void space to the pad. The pad is further configured to move into contact with an object to which the ink is transferred. In a present embodiment, a controller controls the fluid jetting device. 
         [0011]    A contemplated cliché forming fluid is UV curable and the means for curing the fluid is a UV energy source. 
         [0012]    In one embodiment, the support member is an elongate flexible element. The system can including a dispenser for dispensing the support member and a take up for taking up the support member following printing. 
         [0013]    The ink delivery system can include an ink cup and a doctor blade for delivering ink to the cliché and depositing ink in the at least one void space, and for wiping excess ink from the cliché. 
         [0014]    A digital cliché media and a method for pad printing are also disclosed. 
         [0015]    These and other features and advantages of the present invention will be readily apparent from the following detailed description, in conjunction with the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    The benefits and advantages of the present invention will become more readily apparent to those of ordinary skill in the relevant art after reviewing the following detailed description and accompanying drawings, wherein: 
           [0017]      FIG. 1  is a schematic illustration of an embodiment of a digital cliché pad printing system embodying the principles of the present invention, the cliché being illustrated in partial cross-section to show the void spaces therein; and 
           [0018]      FIG. 2  is an exemplary letter “O” formed in accordance with the principles of the present invention and provided for explanatory purposes. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    While the present invention is susceptible of embodiment in various forms, there is shown in the drawings and will hereinafter be described a presently preferred embodiment with the understanding that the present disclosure is to be considered an exemplification of the invention and is not intended to limit the invention to the specific embodiment illustrated. 
         [0020]    It should be understood that the title of this section of this specification, namely, “Detailed Description Of The Invention”, relates to a requirement of the United States Patent Office, and does not imply, nor should be inferred to limit the subject matter disclosed herein. 
         [0021]    Referring now to  FIG. 1  there is shown a schematic illustration of a digital cliché pad printing system  10 . The illustrated system  10  includes various components of a conventional pad printing system, including a supply  11  of ink  12 , an ink cup  14  with a doctor blade  16  and a printing pad  18 . The pad  18  is a resilient member the moves into contact with an inked image-containing member (typically a cliché  20  and referred to herein as a cliché or an image-containing member) and picks up the image from the cliché  20 . The pad  18  is resilient so that it can transfer the image, in total, onto a non-planar surface. 
         [0022]    In a typical arrangement, the pad  18  reciprocates (as indicated at  22 ) to move into contact with the image-containing member  20  and away from the image-containing member/cliché  20 . Various configurations can be used to then move the pad  18  into contact with an object onto which the image is to be transferred. One arrangement is illustrated in Hessert et al., U.S. Pat. No. 7,210,405, commonly assigned with the present application and incorporated herein by reference. 
         [0023]    Unlike known pad printing systems, the present system  10  uses a digitally-created cliché  20 . It enables the decoration of complex contoured shapes, symmetric shapes, near flat shapes and flat shapes, and any other shape that can be decorated using a conventional pad printing process. 
         [0024]    In a present embodiment, the cliché  20  is created on a supporting medium/media  24 , preferably a flexible, transportable supporting media, such as a paper tape, foil, polymeric material or the like. The supporting media  24  is dispensed from a supply  26 , such as a roll. 
         [0025]    As with other digital systems that use a controller  27 , such as a machine (computer) controller, the supporting media  24  is presented to a fluid jetting device  28  or the like, such as, or similar to, an ink jetting device. A cliché-forming material  30 , such as a fluid and/or ceramic-based material, is expressed from the jetting device  28  onto the supporting media  24 . Unlike conventional printing systems, in the present digital cliché system  10 , the cliché-forming material  30  is jetted in the image of the negative space  36  (see  FIG. 2 ), and is jetted so as to build up those regions that define the negative space  36 . For example, referring to  FIG. 2 , for creating the letter “O” in the cliché  20 , the cliché-forming material  30  would be jetted to create the central solid circular portion (shown cross-hatched as indicated at  32 ) and the outer periphery of the letter (shown cross-hatched as indicated at  34 ). This would define the open area (negative space, as indicated at  36 ) between the central solid circular portion and the outer periphery as the letter O. 
         [0026]    Once the negative space  36  of the cliché  20  is created, conventional printing methods, e.g., pad printing methods, are used. That is, using an ink cup  14  or other ink delivery system, the negative space  36  is flooded with ink  12  and the cliché  20  is scraped clean such as by a doctor blade  16  on the ink cup  14 . The pad  18  is then brought into contact with the cliché  20  and the ink  12  in the negative spaces  36  is transferred onto the pad  18 . The pad  18  is then moved into contact with the object onto which the image is to be transferred. 
         [0027]    Unlike known methods for creating clichés (which are subtractive processes—that is, material is removed from a plate), as set forth above, the present digitally created cliché  20  is formed by an additive process, or by depositing a cliché-forming material  30 , such as a curable fluid, onto the support media  24 . In a presently contemplated embodiment, the support media  24  and cliché-forming material  30  are co-engineered (custom engineered) to create a non-elastic member having high adhesion (between the cliché-forming material  30  and the media  24 ), and a smooth finish of the cliché-forming material  30 . Preferably, the fluid or cliché-forming material  30 , which is applied in a drop-on-demand type system (such as a piezo ink jet, thermal ink jet or the like), dries into a relative hard, non-absorbing state. 
         [0028]    In a contemplated digitally created cliché  20 , the cliché-forming material  30  is an energy (e.g., ultraviolet—UV) curable material. Such a material  30  can be formulated to reduce or eliminate the use of solvents necessary to carry the material, and to enable immediate or almost immediate use as a cliché surface. Other materials, such as epoxies and the like (preferably immediate or almost immediate curing) are also contemplated. 
         [0029]    As seen in  FIG. 1 , in one anticipated system and method, the support medium  24  is supplied from a roll  26  and is conveyed through a jetting station  38 , at which a fluid jet device  28  jets fluid/clichë-forming material  30  onto the support medium  28  in a negative of the desired image. 
         [0030]    The support medium  24  with the deposited cliché-forming material  30  is then conveyed through a UV curing station  40  to cure the cliché-forming material  30 , such as fluid, on the support medium  24 . The hardened cliché-forming material  30 , which is built up (additive), creates the conventional cliché  20 , in that the negative spaces  36  ( FIG. 2 ) are void spaces for receiving ink. 
         [0031]    The cliché  20  on the support medium  24  is then transported to an ink transfer station  41  at which an ink cup  14  is moved over the cliché  20  to deposit ink  12  in the void spaces  36  and a doctor blade  16  removes or scrapes excess ink  12  from the surface of the cliché  20 . Alternately, the ink cup  14  can be stationary and the cliché  20  (web) moved relative to the ink cup  16 . The pad  18  is then moved into contact with the cliché  20  to transfer ink  12  onto the pad  18 , which is then moved into contact with the object onto which the image is to be transferred. 
         [0032]    Alternately, the support medium  24  can be a porous material to enable ink  12  to permeate the image area and be presented to the printing pad  18  without the surface flooding and doctoring steps. 
         [0033]    The support media  24  can be wound onto a waste roll  42  and discarded or reused/recycled. The cliché-forming materials  30  can also be of the type to be discarded or perhaps recycled. As set forth above, the cliché  20  itself can be used for short run or single application printing runs. Due to the relatively inexpensive nature of the support media  24  and the cliché-forming material(s)  30  used, and the reduced time (labor) needed to create a cliché  20 , such limited production runs can now be accomplished with the same high quality results as conventional pad printing processes. 
         [0034]    Alternately the cliché support medium  24  can be a rigid support material, such as metal, ceramic or glass, upon which the additive process is applied to create the negative image cliché surface. In such an embodiment, the support medium  24  can be moved in a rotary fashion past the additive process, any curing process, inking/doctoring process and pad printing process. A final station can be configured to remove the additive or cliché-forming material  30  and prepare the surface for a new application of or cliché-forming material  30  to define a new image. 
         [0035]    By the present method, the additive cliché manufacturing process  10  can be used to create a unique image for each cycle of the printing system. Of course, each image can be used to decorate several items in succession before presenting a new image for printing. 
         [0036]    It will be appreciated that one or more fluid jetting devices  28  can be used to apply the cliché-forming material  30  to the support media  24  to effect an efficient process. It will also be understood from the description above that the various components, e.g., the fluid jetting device(s)  28 , fluid jetting station  38 , the curing station  40 , the ink transfer station  41 , and the like, can be separate from one another by space, by shrouds  44 , or by other separating means as required. Given that space is often at a premium and most machines are designed with the smallest practical footprint, it is envisioned that partitions and/or shrouds  44  will be used to separate the stations  38 ,  40 ,  41  as necessary. 
         [0037]    It will also be appreciated that any additive type of additive process can be used to create the cliché  20 . For example, currently known (and to be developed)  3 -D printing technologies, rapid prototyping technologies, other additive manufacturing processes can be used to create the cliché surface. To this end, the material can be jetted or, if solid or powdered, deposited onto the support media and allowed to harden (generally cure), for use. It is preferred that curing occurs immediately or almost immediately so as to provide an efficient printing process. 
         [0038]    All patents referred to herein, are incorporated herein by reference, whether or not specifically done so within the text of this disclosure. 
         [0039]    In the disclosure, the words “a” or “an” are to be taken to include both the singular and the plural. Conversely, any reference to plural items shall, where appropriate, include the singular. 
         [0040]    From the foregoing it will be observed that numerous modification and variations can be effectuated without departing from the true spirit and scope of the novel concepts of the present invention. It is to be understood that no limitation with respect to the specific embodiments illustrated is intended or should be inferred. The disclosure is intended to cover by the appended claims all such modifications as fall within the scope of the claims.