Patent Publication Number: US-2016243886-A1

Title: Digital imaging screen printing process

Description:
CLAIM OF PRIORITY 
     This application claims the benefit of U.S. Provisional Application No. 62/120,193, filed 24 Feb. 2015. The information contained therein is hereby incorporated by reference. 
    
    
     BACKGROUND 
     1. Field of the Invention 
     The present application relates generally to screen printing and digital printing heat transfers, and more particularly to an improved process which combines the techniques of screen printing and digital printing to create a heat transfer. 
     2. Description of Related Art 
     Screen printing, by which ink is pressed through a stencil which is supported by a woven mesh to create an image on a substrate, such as a garment of clothing, has been a form of printing for a long time. Screen printing templates typically include multiple colors. The current process for printing a multi-colored image has many disadvantages. 
     In particular, each color on a template is typically printed with a separate screen. This necessitates a plurality of machines to be used to generate a single image. The result is a multi-stage process which increases time and costs to produce the image. Many of these disadvantages were addressed by the advent of digital printing heat transfers, by which a printer is used to create a digitally printed design onto a heat transferable substrate which is then applied to a garment using heat and pressure. The substrates, however, have limitations, such as the inability to transfer to dark colored garments, the inability to print white or gradients, the need to weed the design before transferring, cracking and peeling of prints, and so forth. The heat transferable substrates are lacking. 
     An improved substrate transfer paper is needed which leads to a more efficient printing process. Although great strides have been made, considerable shortcomings remain. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The novel features believed characteristic of the application are set forth in the appended claims. However, the application itself, as well as a preferred mode of use, and further objectives and advantages thereof, will best be understood by reference to the following detailed description when read in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of a transfer paper substrate according to the preferred embodiment of the present application. 
         FIG. 2  is an exploded side view of the layers of the transfer paper substrate of  FIG. 1 . 
         FIG. 3  is a chart of steps taken to make the transfer paper substrate of  FIGS. 1 and 2 . 
         FIG. 4  is an exemplary digital image for use in the screen printing using the transfer paper substrate of  FIG. 1 . 
     
    
    
     While the substrate and method of the present application is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the application to the particular embodiment disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the process of the present application as defined by the appended claims. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Illustrative embodiments of the preferred embodiment are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developer&#39;s specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure. 
     In the specification, reference may be made to the spatial relationships between various components and to the spatial orientation of various aspects of components as the devices are depicted in the attached drawings. However, as will be recognized by those skilled in the art after a complete reading of the present application, the methods described herein may be positioned in any desired order. The use of terms to describe a spatial relationship between various components or to describe the spatial orientation of aspects of such components should be understood to describe a relative relationship between the components or a spatial orientation of aspects of such components, respectively, as the device described herein may be oriented in any desired direction. 
     The substrate and method in accordance with the present application overcomes one or more of the above-discussed problems commonly associated with existing printing processes. Specifically, the substrate of the present application is configured to permit the single stage screening process of a multi-colored digital image. The image is transferrable onto a piece of fabric in a single heat transfer step. The image does not need to be weeded afterwards and is not limited in color selection. The present application discloses the characteristics of the heat transferable substrate that is configured to accept a digitally printed image. Furthermore, the substrate herein is configured to permit for a more simplified and efficient method of screen printing. These and other unique features of the system are discussed below and illustrated in the accompanying drawings. 
     The substrate and method will be understood, both as to its structure and operation, from the accompanying drawings, taken in conjunction with the accompanying description. Several embodiments of the device may be presented herein. It should be understood that various components, parts, and features of the different embodiments may be combined together and/or interchanged with one another, all of which are within the scope of the present application, even though not all variations and particular embodiments are shown in the drawings. It should also be understood that the mixing and matching of features, elements, and/or functions between various embodiments is expressly contemplated herein so that one of ordinary skill in the art would appreciate from this disclosure that the features, elements, and/or functions of one embodiment may be incorporated into another embodiment as appropriate, unless otherwise described. 
     The substrate and method of the present application is illustrated in the associated drawings. The substrate includes multiple layers of various elements configured to accept a printed image. The layers include a plastisol mixture and a coating of non-adhesive powder (i.e. paper mache powder). The image is printed across the powder. Once printed, the substrate is modified to further include additional layers to allow for adhesion to the fabric. An additional plastisol layer is added as well as an adhesive powder. The locating of the image between two layers of plastisol materials allows for the self-weeding characteristic and freedom to use any colors. Additional features and characteristics of the substrate are illustrated and discussed below. 
     Referring now to the drawings wherein like reference characters identify corresponding or similar elements in form and function throughout the several views.  FIGS. 1-2  illustrate transfer paper substrate  10 .  FIG. 1  provides a perspective view wherein the substrate includes a first stage layer configured to accept a digitally printed image. It is important to note that substrate  10  is illustrated in  FIG. 1  is in a condition prepared to accept the image. A second stage layer is applied after printing of the image to allow for the efficient and clean transfer of the image to the fabric. It is an object of the method of this disclosure to utilize substrate  10  to sandwich and locate a digitally printed image  17  between opposing layers of plastisol. Plastisol is used to transfer and adhere the image  17  to the fabric.  FIG. 2  illustrates the various stage layers in association with substrate  10 . 
     The system of the present application is configured to include an improved transfer paper substrate  10  to produce a full color, no peel transfer for dark or light colored images. The screen printing process of the present application is configured to use substrate  10  to receive digital color prints and then transfer such prints directly to a fabric material in a single step heating process. The color print/image may utilize one or more colors. Transfer paper substrate  10  is developed for the printing industry, using a combination of digital aqueous inkjet printing and screen printing to produce a full color. It is preferred that the images are printed using a pigment based printer as opposed to a dye based printer. 
     As seen in  FIG. 2 , substrate  10  is illustrated having the first stage layer  11  and a second stage layer  12 . In its base form, substrate  10  includes the first stage layer  11 . In this form, substrate  10  is prepared for transportation, sale, and the acceptance of digitally printed images  17 . These may be mass produced following a series of steps (see  FIG. 3 ). 
     Referring also to  FIG. 3  in the drawings, a series of steps are illustrated in a chart  50  for the creation and use of substrate  10 . Substrate  10  includes first stage layering  11 . First stage layering  11  includes a plastisol mixture  13  and a non-adhesive powder  15 . Mixture  13  is applied directly to paper  14 . Powder  15  is applied over mixture  13 , opposite paper  14 . Paper  14  may be any type of paper suitable for screen printing in the industry. An example would be standard 20 lb white paper. Alternative colors and weights of paper may be used. 
     Mixture  13  is a combination of elements mixed together, namely plastisol, a water reducer, and talc powder. Plastisol forms a solid layer when it is heated. The water reducer is used to counteract the hardened nature of plastisol, by weakening the bond of the plastisol. Water reducer is water based and does not normally mix well with plastisol. Talc powder is a solvent and is added to allow both the water reducer and plastisol to mix. The specific mixing ratios may be adjusted to vary the desired results. The idea is to create a weaker bond in the plastisol to allow part of the image to pull off when substrate  10  is removed after the heat press step. Mixture  13  helps provide the characteristic of being self-weeding. The term weeding refers to the extra step needed to remove portions of most conventional digital transfer paper, which is not needed with substrate  10  and the associated screen printing process. 
     As stated above, a thin coat of mixture  13  is applied to a first surface  16  of paper  14 . Mixture  13  may be applied to paper  14  in different ways. For example, mixture  13  may be screen printed onto the paper, but any means that produces a thin smooth plastisol layer may be used. Mixture  13  is flashed at 350 degrees F. for 20 seconds on paper  14 . The temperature and time duration may be adjusted and is not herein limiting. At this point, mixture  13  has a tacky feel. Paper  14  and mixture  13  are dusted with powder  15 . The excess powder  14  is then removed either with compressed air or by wiping. Substrate  10  is now ready to accept printing. By removing the tacky feel of mixture  13 , substrate  10  may be stacked and shipped more easily without fear of damage from sticking. 
     Once image  17  has been selected and printed onto mixture  13 , second stage layer  12  is applied. Layer  12  includes a layer of plastisol  19  and a layer of adhesive powder  21 . Plastisol  19  is applied directly over image  17  and over non-adhesive powder  15  where image  17  does not exist. Image  17  is sandwiched between two layers of plastisol or plastisol based materials (items  13  and  19 ). Powder  15  acts to prevent the bonding of plastisol  19  directly with mixture  13 . However, image  17  is in contact with plastisol  19  and mixture  13 . Contact with mixture  13  occurs from printing. When paper  14  is removed after the heating process, part of image  17  remains on first stage  11  and substrate  10  in general. Adhesive powder  21  is applied over plastisol  19  and is configured to provide adhesion between plastisol  19 , image  17 , and the fabric. In order to initiate a transfer of the digital image, substrate  10  with the digital image  17  and layers  11  and  12  are laid over the fabric such that layer  12  is in contact with the fabric. Heat is applied that induces the transfer to the fabric. The paper is removed after a designated time for cooling. The use of powder  15  along with the image between plastisol  19  and mixture  13  allows for the self-weeding characteristic of the screen printed image. 
     Referring now also to  FIG. 4  in the drawings, an exemplary digital image for use with substrate  10  and the digital imaging process herein disclosed is shown.  FIG. 4  designates areas that are black (garment)  103 , colored  105 , and white  107 . The white areas are a patterned series of circles laid over a colored  105  background. The image is loaded into design software and printed on substrate  10  across first stage layer  11 . The digital image is mirrored so as to print in reverse on substrate  10  to ensure the correct orientation upon transferring. Printing of the digital image may be done in a single process. The digital image may include one or more colors. 
     Once printed, second stage layer  12  is applied to substrate  10  and the digital image. This may be applied as follows: substrate  10  is aligned with the digitally printed image onto a template. The plastisol layer  19  is screened onto first stage layer  11  and the digital image. The digital image print is now sandwiched between two layers of plastisol. The plastisol does not adhere to the powder  13  and will not transfer at those areas. Taping may be used to secure substrate  10  in the template. 
     Substrate  10  is removed from the screen. The new plastisol layer is covered with an adhesive powder  21 . Excessive or excess powder is to be removed. Compressed air may be used to remove any remaining adhesive powder that may be left outside of the print area. Cure the white ink and adhesive as necessary. 
     In order to transfer the design to the substrate, place the first surface of the transfer face down on the garment or fabric. Heat is applied to bond the image and transfer it to the garment substrate. Heat press the image at 330 degrees for 10-15 seconds with medium pressure. Peel cold. The design is configured to transfer completely and self-weed any non-printed areas. 
     The resulting transfer has several unique advantages over traditional transfer methods, such as at least the following: (1) low cost of printing; (2) ease of a single step screening of colored images; (3) printed images sandwiched between layers of plastisol to permit the transfer of multicolored images and self-weeding; (4) low set up time; (5) high quality images to resist cracking, peeling, and fading after washing; and (6) printing of full color images along with specialty plastisol inks. 
     Use of the present process and transfer paper eliminates hassles that exist with conventional processes and papers. “Patterned” images may be generated within the software and printed as well as different text styles (i.e. wrap text in colorful patterns), specialty styles (i.e. Puff, Glow in the dark, granite, etc.), and simulated embroidery to name a few. 
     The particular embodiments and method disclosed above are illustrative only, as the application may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. It is therefore evident that the particular embodiments disclosed above may be altered or modified, and all such variations are considered within the scope and spirit of the application. Accordingly, the protection sought herein is as set forth in the description. It is apparent that an application with significant advantages has been described and illustrated. Although the present application is shown in a limited number of forms, it is not limited to just these forms, but is amenable to various changes and modifications without departing from the spirit thereof.