Abstract:
The present invention relates improved device is provided for holding down textile the material on the platen of the digital printer. The inventive device includes a textile gripping material formed to define a border band on the periphery of the platen. The border material has a structure that engages/grips the textile and hold the textile in place. In operation, the textile is laid onto the platen surface and the edges are pulled taut to align the textile and remove wrinkles and the textile is next pressed onto the border material to be engaged by the border material. The border material grips and holds the textile in position, to provide a smooth textile surface on which the ink jets are applied. After the printing operation, the textile is lifted off of the border material and removed from the platen.

Description:
[0001]    The present invention claims the benefit of the filing date of the provisional application filed on 9 Oct. 2012 by the same inventor hereof, Darren Livingston, for “Digital Printer Platen Material Holding Apparatus” and is an improvement in the field of U.S. Pat. No. 7,854,200. 
     
    
     BACKGROUND OF INVENTION 
       [0002]    The invention relates generally to digital printing machines wherein, as is known, the printer prints on textiles directly. Digital printing is a much newer process than the long established screen printing technique, although the latter technique is still in wide use. The digital printing method makes possible the reproduction of complicated design, to print colors and detail that were not feasible before, to readily make changes in design etc. 
         [0003]    Digital printers can effectively print on different type materials and on material of different sizes and on material placed or positioned on a relatively large platen. It has been found that the materials positioned on the platen must be wrinkle free, and be stretched tautly and smoothly over the platen to provide satisfactory printing results. Since the platens and the material positioned thereon are both relatively of large size, better means have been sought for positioning/mounting the material on the platen in a smooth, wrinkle free and firmly taut fashion. 
       SUMMARY OF INVENTION  
       [0004]    The present invention relates to a digital printer for textile material wherein an improved device is provided for holding down the material on the platen of the digital printer. The material is held down in a smooth, firm and wrinkle free position for purposes of suitably printing images and/or text thereon. More specifically, the inventive device includes a platen having a flat center surface surrounded by a border of textile engaging material mounted on the periphery of the platen. The border material has a structure that allows it to engage/grip the textile and hold it in place. One useful type of the textile holding material used in the invention is known as lint brush material. 
         [0005]    The textile to be printed on is laid onto the platen surface and the edges are pulled taut to position and align the textile and remove wrinkles. The textile is next pressed/patted down onto the border material to be engaged by the border material. The border material grips and holds the textile in position, to thereby provide a smooth textile surface on which the ink jets are applied. After the printing operation, the textile is lifted off of the border material and removed from the platen. 
         [0006]    The foregoing features and advantages of the present invention will be apparent from the following more particular description of the invention. The accompanying drawings, listed herein below, are useful in explaining the invention. 
     
    
     
       DRAWINGS 
         [0007]      FIG. 1  depicts a textile digital printing machine of the type incorporating the present invention and the platen assembly on which the inventive device is positioned; 
           [0008]      FIG. 2  is a view of second embodiment of a textile printing machine where an inventive platen assembly is utilized with a printing machine having a conveyor system for inserting and removing the platen (and the textile draped there over) from the printing machine; 
           [0009]      FIG. 3  is an isometric view of the platen assembly shown in  FIG. 2 ; 
           [0010]      FIG. 4  is an exploded view of the platen assembly of  FIG. 3  to more clearly show the structure of the platen assembly and the cantilever projections extending over the support; 
           [0011]      FIG. 5  is view of another embodiment of the platen assembly of  FIG. 3  wherein a neck profile if formed on the platen plate and provides an effective feature particularly when printing T-shirts; 
           [0012]      FIG. 6  is a relatively enlarged view in cross section to show the mounting of the border material positioned on the platen and more particularly show the groove or recess formed on the edges of the platen; 
           [0013]      FIG. 7  is an isometric view to depict the gripping surface of one type of border material; 
           [0014]      FIG. 8A-8C  show details of various ways of positioning the border material on a platen wherein  FIG. 8A  shows beveled edges,  FIG. 8B  shows a platen with a square edge and the border material affixed to the top and side of the platen and  FIG. 8C  shows the border material wrapped completely around the edge of the platen; and, 
           [0015]      FIG. 9  is an enlarged view to show an embodiment of a preferred type of border material. 
       
    
    
     DESCRIPTION OF THE INVENTION  
       [0016]      FIG. 1  depicts a digital printing machine  10  of well-known type wherein a textile  15  material (see  FIG. 5 ) on which text, photos, caricatures, figures etc., is to be selectively printed. The printing machine  10  depicted in  FIG. 1  is generally similar to the machine disclosed in the aforementioned U.S. Pat. No. 7,854,200.  FIG. 1  depicts the housing  11  including a platen  17  on which the textile  15  (see  FIG. 40 ) is to be positioned. Basically, the platen  17  is a cantilevered structure that extends over a support member. As shown in  FIG. 1  platen  17  is commonly rectangular in shape may be mounted on an elongated flat plate/track  19 . Platen  17  is slid/pushed into the housing  11  for the printing operation. For printing, the textile  15  is positioned to encase the platen  15  (see  FIG. 5 ) with preferably only one layer of the textile lying flat over the platen and other textile layers being under the platen. 
         [0017]      FIG. 2  shows another embodiment of a printing machine  10 A including a platen assembly  25 . Printing machine  10 A has a housing  11 A in which a conveyor loop  23  of a suitable known design is mounted. Platen assembly  25  comprises a second embodiment of the platen labeled  17 A; basically platen  17 A is mounted on a support pedestal but otherwise is similar to platen  17 . As depicted in  FIG. 2 , platen assembly is positioned on a conveyor  23  to be moved into the interior of housing  11 A for printing the textile that is positioned on the platen assembly  25 . 
         [0018]    Referring now also to  FIGS. 3 and 4 , platen  17 A is mounted on a spacer block/cube  28 , which in turn is mounted on a base plate  29  which together comprise the platen assembly  25 . Platen  17 A is cantilevered, that is, overhangs or extends beyond the block  28  on four sides. The inventive border material labeled generally as  30  is positioned on the sides generally labeled  32  of the platen  17 A. As can be seen in  FIG. 4 , the sides  32  are beveled. The beveled surface provides a smooth curving surface for the textile  15  to rest on to thereby tend to maintain the textile on the surface of the platen  17 A wrinkle free, taut and smooth. 
         [0019]    In operation, the textile  15  to be printed is placed over platen  17 A (and similarly on platen  17 ). The textile  15 , for example a T-shirt (see  FIG. 5 ), is inserted around the platen with one aide of the T-shirt position on the top flat surface of the platen and the other side around the underside of the platen. The textile  15  is moved to a desired position on the platen and held in a flat unwrinkled condition by the border material  30 , as will be explained. The platen assembly  25  is mounted on conveyor belt  23  of printing machine  10 A and suitable known controls activate the conveyor to move the platen into the printing machine; or, in the embodiment of  FIG. 1  the platen  17  and textile  15  are moved/slid into the printing machine  10  for the printing operation. After printing, the direction of motion of conveyor  23  is reversed and the platen is withdrawn to an initial position and the imprinted textile  15  is taken off of the platen  17 A. In the embodiment of  FIG. 17 , the platen is pulled out of the machine  10  and the textile removed. 
         [0020]    A very large percentage of the textile to be imprinted consists of the well known “T-shirts.” It has been found that it is very convenient to use the disclosed cantilevered platens  17  and  17 A where only one layer of a T-shirt is positioned to rest above the platen surface and the other layer of the shirt is underneath the platens. The cantilevered platen will be partially “wearing” the shirt, see  FIG. 5 . The present inventive border material functions best when only one layer of fabric is on the upper surface of the platen. 
         [0021]    The exploded view of the platen  25  assembly clearly shows the positioning of the inventive border material  30  on the platen  17 A. As can be seen in  FIG. 3 , the sides  32  of the platen  17 A are beveled and the border material  30  comprising elongated panels or bands are cut/formed to fit or conform to the beveled sides  32 . The border material is suitably attached by adhesive indicated at  33 , or by suitable known clips indicated at  34 . In the embodiments shown in  FIGS. 3 and 4 , the border material  30  extends completely around the sides of the platen  17 A. In the embodiment of  FIG. 5 , the border material extends only on three sides, for reasons to be explained. 
         [0022]    The width of the border material is selected dependent on the textile to be printed and the type of gripping material used, the selected gripping area, and gripping strength desired. It has been found that the wider the border the more grip strength provided, however this may result in less effective print area. In two present embodiments, border materials having widths of ⅜″ and ¾″ have been found effective, although these dimensions are limitations and other widths of border material can be used. 
         [0023]    One type of border gripping material  30  is depicted in  FIG. 7  indicating the material as having a coarse, knobbed or rough surface. The grip layer of border material  30  may also be a coarse, fibrous, foamed material or may be a processed hemp material. One excellent type of a border material  30  is known as “lint brush material.” Lint brush material is textured and may include a warp weave, a knobbed or rough weave, to provide a non-smooth surface. Various types and brands of lint brush material are available commercially, one brand name being “Tricot.” 
         [0024]    Refer now to  FIG. 9  which depicts a preferred embodiment of the lint brush border material  30  used in the present invention. As shown in the enlarged view of  FIG. 9  the border material  30  is mounted on the sides of the platen  17  with the textured surface  39  of the lint brush material  30  facing outwardly. The textured surface  39  depicts flexible extensions or hairs  40  that extend outwardly from the surface and function to engage the textile material  15  when the textile material is pressed or pushed against the surface  39 . That is, the extensions  40  tend to penetrate and sink into the textile, thus gripping and holding the textile in position. Extensions  40  may be made to extend in a single direction or in multiple direction to engage the textile dependent on type of textile which is to be processed. As mentioned above a large percentage of the textiles that are imprinted consist of “T-shirts,” hence a border material such as depicted in  FIG. 9  is well suited for used as the border material. 
         [0025]      FIG. 6  is a view to show the border material  30  positioned on the beveled and grooved side  32  of the platen  17 A. As shown, the border material  30  includes a base layer  35  of any suitable flexible material and a layer of textile gripping material  37 . The base layer  35  is affixed to platen  17 A by adhesive. The groove/recess  41  on side  32  of platen functions to retain the base layer  35  of border material  30  more securely in place. In addition to providing a securing place for the border material the groove  41  also assures that the top surface of platen  17 A plus the thickness of the border material  30  present a smooth level printing surface for the textile  15 . 
         [0026]      FIG. 4  discloses another embodiment of the platen labeled  17 B. One side (the top side) of platen  17 B is contoured to form a neck profile  35  for accommodating placement of textiles and particularly the important T-shirts products on the platen. As mentioned above, T-shirts are the garments on which the printing, text, pictures and characters etc., are most frequently applied. As depicted in  FIG. 5 , in this embodiment of the platen  15 B the one side, the neck profile  35  conveniently provides a means of quickly and more properly positioning the T-shirt on the platen  17 B for the printing process. In the embodiment of  FIG. 4 , border material  30  is not placed on one side of the plated  17 B to conveniently permit the T-shirt to be placed (slipped onto) the platen via the neck profile, arranged, positioned with any engagement gripping by the border material. The T-shirt is then affixed to the border material  30  on the other three sides of the platen. Likewise, for other applications the border material can be placed on only three or possibly even two sides of the platen dependent on the garment  15  being printed. 
         [0027]      FIGS. 8A-8C  show other ways of mounting the border material  30  on to the platens  17 ,  17 A,  17 B. In operation the textile  15  is caused to engage to the border material  15 , and hence when the textile is pulled and stretched to flatten and fit onto the platen, a pulling force will be exerted on the border material. The border material must thus be properly affixed to the pattern. As described with reference to the sides  32  of the platen  17  are recessed to receive the border material which provides a level platen printing surface and also assists in holding the border material in place. 
         [0028]      FIG. 8A  shows a different way for affixing the border material  30 X to a platen  17 X having a beveled edge and wherein the border material  30 X is wrapped around the entire edge of a platen  17 X and adhered by adhesive. In this modification, the border material is of a lesser thickness and slight variation of the border material above the printing plane is acceptable for certain printing operations. 
         [0029]      FIG. 8B  shows a platen  30 Y having a square edge and border material wrapped around the upper and outside edges.  FIG. 8  shows that the edges of the platen have been recessed to compensate for the thickness of the border material  30 Y, to thereby maintain a smooth planar surface on the platen  17 A, similarly as described for  FIG. 6 . In one embodiment, the lint brush material used is an unidirectional hair fabric adhered to ⅛″ thick open cell foam, and the overall thickness is about 3/16″. Accordingly, the platen top was machined as at  44  to provide for a recessed area around the sides of the platen as to maintain the border grip material  30 Y level with the printing plane. 
         [0030]      FIG. 8C  shows a platen  17 Z having the border material  30 Z wrapped around the upper, lower and side edges of the platen  17 Z. Similarly as in  FIG. 8A , the border material is of a lesser thickness and a slight variation of the border material above the printing plane is acceptable for certain printing operations. 
         [0031]    Other such positioning of the border material  30  onto a platen  17  can of course be envisioned. The desired result is that the border material be firmly affixed to the platen to hold the textile  15  flat, wrinkle free, and taut on the planar face of the platens. 
         [0032]    A significant advantage and feature of the present invention, and in particular with the neck profile embodiment of the platen shown in  FIG. 5  is that loading/mounting of T-shirts and most other garments will be quicker/faster with the border grip material than with previously known platens. The border material will catch a T-shirt or other textile at the edge of the platen yet allow the interior portion of the fabric to flatten freely. The full operation is relatively much faster since the operator has to only position and press/pat the garment onto the border material to prepare for the printing cycle. 
         [0033]    While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.