Patent Publication Number: US-7215604-B2

Title: Time indicator assembly

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
   Not Applicable. 
   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
   Not Applicable. 
   TECHNICAL FIELD 
   This invention relates to time indicator assemblies, and in particular to a time indicator assembly including migrating ink that migrates through an opaque layer of material forming part of the assembly to produce a viewable image after a period of time. 
   DESCRIPTION OF THE BACKGROUND ART 
   A known time indicator assembly  1  including migrating ink  2 , such as shown in  FIG. 1 , produces a visible image after a period of time. The migrating ink  2  is applied to a base material  3 , such as by printing, to form a back part  4  of the assembly  1 . The back part  4  is adhesively joined with a front part  5  formed from one or more layers  7 ,  8 ,  9  of opaque and/or transparent material or coatings by an adhesive  6  to form and activate the assembly  1 . Over a period of time, the migrating ink  2  of the activated assembly  1  migrates through the adhesive  6  to form a viewable image. The front part  5  and the back part  4  are not joined together until activation of the time indicator assembly  1  is desired. As a result, properly aligning the front part  5  and back part  4  to form and activate the assembly can be difficult. 
   This problem is solved by a time indicator assembly having a front part and a back part adhesively joined at one edge, such as disclosed in U.S. Pat. Nos. 5,107,470 and 5,974,003 which are fully incorporated herein by reference. These patents disclose an assembly having a front part and a back part similar to the time indicator assembly shown in  FIG. 1 . The back part includes migrating ink applied to a base material, and the front part includes one or more opaque coatings or layers. In order to ensure the front part and the back part are properly aligned, an edge of the front part is adhesively joined to the back part adjacent to the migrating ink. Prior to activation, a release liner interposed between the migrating ink and the front part prevents the migrating ink from contacting the front part and migrating through the opaque layers. When a user wishes to activate the assembly and initiate migration of the ink, the release liner is removed and the portion of the front part overlying the migrating ink is joined to the back part. 
   Since only one edge of the front part is joined to the back part, the front part is free to flop around. The floppy front part causes havoc when printing on outer surfaces of the assembly. Moreover, in one embodiment disclosed in the &#39;470 patent, the release liner is folded over to form a pull tab for removing the release liner and activating the assembly. Prior to activation of the assembly, this folded release liner forms an assembly having an uneven thickness which causes further problems when attempting to print on an outer surface of the assembly. 
   SUMMARY OF THE INVENTION 
   The present invention provides a time indicator assembly having a front part and a back part that can easily pass through a printer. The assembly includes a base substrate forming at least part of the back part having a first surface and a second surface extending between edges. A migrating ink is applied over a portion of the first surface of the base substrate, and a release sheet overlies the migrating ink to prevent migration of the migrating ink toward the front part. In one embodiment, an adhesive is applied over the release sheet and onto the base substrate. The adhesive joins a cover substrate forming at least part of the front part to the base substrate over at least a portion of the release sheet along at least two of the front part edges to prevent the cover substrate from flopping around. Upon removal of the release sheet, the migrating ink migrates through the adhesive to form the image in the cover substrate. In another embodiment a lift strip is formed in at least one of the front part and the back part for easily separating the front part and the back part to expose and remove the release sheet. 
   A general objective of the present invention is to provide a time indicator assembly having a non-floppy front part. This objective is accomplished by securing the front part to at least two edges of the back part. 
   Another objective of the present invention is to provide a time indicator assembly having a front part that is easily separated from the back part to expose a release liner for easy removal. This objective is accomplished in one embodiment of the present invention by providing a lift strip in the one of the front part and back part. 
   The foregoing and other objectives and advantages of the invention will appear from the following description. In the description, reference is made to the accompanying drawings which form a part hereof, and in which there is shown by way of illustration a preferred embodiment of the invention. Such embodiment does not necessarily represent the full scope of the invention, however, and reference is made therefore to the claims herein for interpreting the scope of the invention. 

   
     BRIEF SUMMARY OF THE DRAWINGS 
       FIG. 1  is a cross sectional view of a prior art time indicator assembly formed from two independent parts; 
       FIG. 2  is a perspective view of a time indicator assembly incorporating the present invention in the form of a badge prior to activation; 
       FIG. 3  is a perspective view of the time indicator assembly of  FIG. 2  after activation; 
       FIG. 4  is a sectional view along line  4 — 4  of  FIG. 2 ; 
       FIG. 5  is a sectional view of another embodiment of a time indicator assembly incorporating the present invention; and 
       FIG. 6  is a sectional view of yet another embodiment of a time indicator assembly incorporating the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   A time indicator assembly  10  in the form of a badge is shown in  FIGS. 2–4 , and includes a front part  12  having at least two edges  14 ,  16  fixed relative to a back part  18  by a pressure sensitive adhesive  20 . Migrating ink  22  applied to a top surface  24  of the back part  18  is separated from the adhesive  20  by a release sheet  26 . The time indicator assembly  10  is activated by removing the release sheet  26  and pressing the front part  12  and back part  18  together. Upon activation, the migrating ink  22  migrates through the adhesive  20  until it is visible through a transparent outer layer  28  forming part of the front part  12 . Advantageously, fixing at least two edges of the front part  12  relative to the back part  18  prevents the front part  12  from flopping prior to use and when the time indicator assembly  10  passes through a printer that prints indicia on an exposed surface  66  of the time indicator assembly  10 . 
   The back part  18  includes a base substrate  30  upon which the migrating ink  22  is printed. The base substrate  30  has a periphery defined by the edges  32 ,  34 ,  36 ,  38 , and includes the top surface  24  of the back part  18  and a bottom surface  31 . In the embodiment disclosed herein, the base substrate  30  is rectangular having four edges  32 ,  34 ,  36 ,  38 , however, the base substrate  30  can have any shape, such as a circle wherein each edge is defined by an arc of approximately 90 degrees. The base substrate  30  can be formed from one or more layers of material, such as paper, cardboard, plastic, foil, and the like, without departing from the scope of the invention. Moreover, the back part  18  can include a pressure sensitive adhesive  40  applied to the bottom surface  31  of the base substrate  30  and covered with a release liner  42  to form a badge useable as a name tag that can releasebly adhere to a user&#39;s clothing. 
   In the embodiment disclosed in  FIGS. 2–4 , the migrating ink  22  is applied to a portion of the back part top surface  24  and spaced inwardly from at least two of the base substrate edges  32 ,  34 ,  36 ,  38 . The migrating ink  22  defines an image  44 , or other indicia, such as alphanumeric characters, symbols, graphic designs, stripes, and the like. The migrating ink  22  can be any known ink which upon contact with the adhesive  20  migrates therethrough to form the image  44  in the front part  12 , such as disclosed in U.S. Pat. No. 4,212,153 which is fully incorporated herein by reference. Forming an image  44  in the front part  12  or cover substrate  60  does not require the migrating ink  22  to migrate into any part of the front part  12  or cover substrate  60 . The image  44  must, however, be at least viewable through the front part  12  or cover substrate  60  to be formed in the front part  12  or cover substrate  60 . Of course, non-migrating ink can be applied to the base substrate  30  to hide the image  44  formed by the migrating ink  22 , and/or reduce the contrast between the background color seen through the front part  12  and the image  44 , without departing from the scope of the invention. 
   The release sheet  26  overlies the migrating ink  22  and separates the migrating ink  22  from the adhesive  20  to prevent activation of the time indicator assembly  10 . The release sheet  26  can be formed from any known material impervious to the migrating ink  22  and releasable from the adhesive  20 , such as coated paper, foil, and the like, without departing from the scope of the claims. 
   The adhesive  20  overlies the release sheet  26  and base substrate  30  to form an adhesive layer that fixes the front part  12  relative to the base substrate  30 . The adhesive  20  can be any adhesive known in the art, such as a rubber or acrylic based pressure sensitive adhesive. In one embodiment, the adhesive  20  includes an opaqueing agent, such as titanium dioxide blended in a polymer mixture, to form an opaque adhesive which obscures the migrating ink  22  from view as the migrating ink  22  migrates therethrough. Of course, the adhesive  20  can be clear and an opaque layer forming part of the front part  12  can be provided to obscure the migrating ink  22  from view as the migrating ink  22  migrates through the adhesive  20  and opaque layer following activation of the time indicator assembly  10 . 
   The adhesive  20  is applied over the release sheet  26  and onto the base substrate  30  adjacent at least two of the front part edges  14 ,  16  to fix the two edges  14 ,  16  of the front part  12  relative to the two edges  32 ,  34  of the base substrate  30 . The edges  14 ,  16  of the front part  12  fixed relative to the base substrate  30  can be opposing edges, such as edges  14 ,  16 , or adjacent edges, such as edges  14 ,  50 , without departing from the scope of the invention. Advantageously, by fixing at least two edges of the front part  12  relative to the base substrate  30 , the front part  12  is prevented from flopping around which allows the time indicator assembly  10  to pass through a printer without jamming the printer. Advantageously, the adhesive  20  can be spaced inwardly from at least one edge of the front part  12  to allow a user to slip a fingernail, or other object, between the front part  12  and base substrate  30  to separate the front part  12  from the base substrate  30  to expose and remove the release sheet  26 . 
   In the embodiment disclosed herein, the front part  12  is bounded by the edges  14 ,  16  and edges  50 ,  52  which coincide with edges of a cover substrate  60  forming the front part  12 . The cover substrate  60  is formed from an inner layer  62  and the outer layer  28  of material which overlies and covers the migrating ink  22 . The cover substrate  60  is joined to the base substrate  30  and the release sheet  26  by the adhesive  20 . Although only two layers  62 ,  28  are disclosed, any number of layers can be used to form the cover substrate  60  without departing from the scope of the invention. 
   The inner layer  62  can be formed from an opaque material including a non-porous polymer containing titanium oxide, or other opaqeuing agent, through which the migrating ink  22  can migrate. Of course, if the adhesive  20  is opaque, the opaque inner layer  62  can be eliminated, or be substituted with a transparent layer, such as a non-porous polymer including plasticized PVC (polyvinyl chloride), semiplasticized PVC, acrylics, polyurethanes and hytrel, and the like, without departing from the scope of the invention. Moreover, any number of inner layers can be provided without departing from the scope of the invention. 
   The outer layer  28  is transparent and impervious to the migrating ink  22 , such as a clear inert acetate or polyester film, to allow a user to see the image  44  formed by the migrating ink  22  once it has migrated through the adhesive  20  and/or opaque inner layer  62  while preventing external migrating ink from passing through the outer layer  28  from an external source of migrating ink. Preferably, ink can be applied to an outwardly facing surface  66  of the outer layer  28 , such as by printing, stenciling, writing, and the like, to form indicia  68  on the outwardly facing surface  66 . 
   A lift strip  64  is formed in the back part  18  adjacent to the migrating ink  22  by forming a cut  33  spaced inwardly from one edge  34  of the back part  18 . The lift strip  64  is adhesively fixed to the front part  12 , and permits a person to easily lift the front part  12  to expose and remove the release sheet  26  to activate the assembly  10 . Although forming the lift strip  64  in the back part  18  is disclosed, the lift strip  64  can be formed in the front part  12  without departing from the scope of the invention. 
   In use, the time indicator assembly  10  including the release sheet  26  interposed between the front part  12  and back part  18  is passed through a printer for printing indicia  68  thereon. Advantageously, by securing the front part  12  and back part  18  relative to each other by fixing at least two edges  32 ,  34  of the base substrate  30  relative to two edges  14 ,  16  of the front part  12 , the front part  12  cannot flop around and jam the printer. In  FIG. 2 , the front part edge  52  is shown rolled back from the base substrate edge  38  to show the release sheet  26  disposed therebetween. 
   The time indicator assembly  10  is activated by a user grasping the lift strip  64  and separating the front part  12  from the back part  18  without breaking the adhesive bond between at least one pair of adhesively bonded edges, such as edges  32 ,  14 , to expose the release sheet  26 . The release sheet  26  is removed and the front part  12  and the back part  18  are then pressed together to urge the adhesive  20  into contact with the migrating ink  22  to activate the time indicator assembly  10 . Advantageously, by maintaining one pair of edges, such as edges  32 ,  14 , together, the edges of the front part  12  and back part  18  remain aligned when pressed together. 
   In other embodiments shown in  FIGS. 5 and 6  where like components are assigned like reference numbers, an adhesive  70  can be interspersed with the migrating ink  22 , such as shown in  FIG. 5 , or applied adjacent to the migrating ink  22 , such as shown in  FIG. 6 , to fix the release sheet  26  relative to the back part  18  which is adhesively fixed to the front part  12  to fix at least two edges of the front part  12  relative to the back part  18 . Advantageously, in the embodiment shown in  FIG. 6 , the lift strip  64  is adhesively fixed to the release sheet  26  which is easy to grasp for removing the release sheet  26 . Advantageously, in all of the embodiments, the release sheet  26  remains flat to provide a flat surface for printing on the time indicator assembly  10 , and the time indicator assembly  10  remains inert in its composite construction prior to removal of the release sheet  26 . Of course, the release sheet  26  can be folded or extend past one of the edges of the time indicator assembly  10  to provide a tab for easy removal of the release sheet  26 . 
   While there has been shown and described what is at present considered the preferred embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention defined by the appended claims.