Abstract:
A book binding structure which includes at least one adhesive binder strip and a pair of supporting sheets for supporting the binder strip during a binder strip printing process. Opposite ends of the binder strip are supported on separate support sheets, which are coupled together only by way of the binder strip to allow independent movement of the ends of the binder strip. The sheets are arranged to support the binder strip as is passes along the paper path of a conventional printer.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to the field of bookbinding and in particular to binder strips used in binding a stack of sheets to form a bound book. 
     2. Description of Related Art 
     Binder strips utilizing heat activated adhesives are commonly used to bind a stack of sheets utilizing a desk top binding machine. A typical binder strip is disclosed in USPNo. 4,496,617, the contents of which are fully incorporated herein by reference. Referring to the drawings, FIG.  1 A/B depict such a conventional binder strip  18 . One side  18 B of the strip, as shown in  FIG. 1B  includes a layer of heat activated adhesive which is formed on a flexible substrate of paper or plastic. A conventional binding machine operates to apply heat and pressure to the binder strip and to fold the strip around the edge of a stack of sheets to be bound. The adhesive, upon cooling, secures the edges of the sheets together and also to the substrate. Binder strips are available in differing widths to accommodate stacks of differing thickness. A typical binding machine for carrying out the actual binding process is disclosed in U.S. Pat. No. 5,052,873, the contents of which are also fully incorporated herein by reference. 
     It is frequently desirable to provide descriptive information and other graphics on the printable side  18 A of  FIG. 1A  of the binder strip before a book is bound. Such graphics may include, by way of example, a title, a listing of authors and/or a company logo. U.S. Pat. No. 6,027,265, the contents of which are also fully incorporated herein by reference, discloses a desk top binder strip printing machine capable of printing binder strips. This printing machine is capable of reliably printing binder strips, including strips which have roughly textured surfaces. However, the machine is dedicated to printing binder strips and is significantly more expensive than most desk top printers. 
     There is a need for a book binding structure which enables the printing of binder strips using conventional, general purpose printers. As will become apparent upon a reading of the following Detailed Description of the Invention together with the drawings, the present invention provides these and other advantages. 
     SUMMARY OF THE INVENTION 
     A book binding structure is disclosed for enabling the printing of graphics on binder strips used in binding books. The structure includes at least one elongated adhesive binder strip, a support sheet and an extension sheet. Each of the binder strips includes a printing side and an adhesive side opposite the printing side. The adhesive sides each include first and second opposite end portions and an intermediate portion disposed intermediate the end portions with the intermediate portion comprising a majority of a length of the binder strip. Only the first end portion of the at least one binder strip is secured to the support sheet, with only the second end portion being secured to the extension sheet, with the intermediate portion of the adhesive side being unsecured to either the support or the extension sheets. Preferably the extension sheet extends past the trailing edge of the binder strip a minimum distance 
     The support and extension sheets support the at least one binder strip as is passes through the paper path of a conventional printer. This arrangement decouples the opposite ends of the binder strip from one another to compensate for dimensional changes in the binder strips even after being mounted on the support and extension sheets. In addition, the extension sheet helps to secure the trailing ends of the binder strips as they pass under the print head. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG.  1 A/B depict a conventional individual binder strip. 
         FIG. 2  is a plan view a book binding structure in accordance with one aspect of the present invention showing three binder strips after printing. 
         FIG. 3  is a plan view of the book binding structure of  FIG. 2  prior to printing. 
         FIG. 4  is a perspective view of the  FIG. 3  book binding structure. 
         FIGS. 5 and 6  are further perspective views of the  FIG. 3  book binding structure illustrating that one end of the binder strips in the book binding structure is free to move with respect to the opposite end. 
       FIG.  7 A/B/C are simplified schematic diagrams which facilitate an understanding of the operation of the subject book binding structure. 
         FIG. 8  is a simplified diagram of a portion of a conventional ink jet printer. 
         FIG. 8A  is an expanded view of the print head and paper feed aspects of the  FIG. 8  printer showing a part of the subject book binding structure. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring again to the drawings,  FIGS. 3-6  illustrate one embodiment  20  of the subject book binding structure. This embodiment permits three binder strips  26 ,  30  and  34  to be simultaneously printed, preferably using a conventional desk top ink jet printer. (Laser printers produce heat during the printing process which is likely to activate the binder strip adhesive, possibly resulting in damage to the printer.) It should be noted that additional binder strips can be provided, particularly if narrower strips are to be printed. In addition, the number of strips can be reduced from three to two or even to one, although the present invention is particularly suited for simultaneously printing multiple strips. 
     The subject book binding structure  20  has a form factor compatible with conventional desk top ink jet printers. The structure includes a support sheet  22 , preferably made from paper stock, that is somewhat wider than the total width of the binder strips  26 ,  30  and  34  and somewhat longer than the strips. These dimensions provide margins  39  around the perimeter of the support sheet  22  which compensates for printer overspray on three sides. The support sheet  22  has a leading edge  22 A that is fed first into the printer input and an opposite trailing edge  22 B ( FIG. 5 ). The binder strips are positioned on support sheet  22  so that the respective leading edges  26 A,  32 A and  34 A of the strips are adjacent the leading edge  22 A of the sheet as shown in  FIG. 3 . The leading edges of each strip are secured to the support sheet  22 . Preferably, this is accomplished by selectively applying heat to a small region of the strip substrate at the strip end so as to activate a small portion of the underlying strip adhesive. This causes each strip to be tacked to the support sheet as indicated by respective drawing elements  28 A,  32 A and  36 A. Once printing has been carried out, a user can then manually separate the strips from the support sheet  22  prior to binding. The strips are positioned laterally over sheet  22  to provide gaps  38  between the strips to further accommodate printer overspray. Note also that the strips are tacked only at the respective extreme ends of the strip, with the intermediate central portion of the strip being free floating. Preferably, the intermediate central portion comprises at least a majority (50%) of the length of the elongated binder strips and preferably at least 80%. 
     The opposite or trailing edges  26 B,  32 B and  36 B are tacked in a similar manner to an extension sheet  24 , near the leading edge  24 A of the sheet as can best be seen in  FIG. 5 . Respective drawing elements  28 B,  32 B and  34 B indicate the regions where the strip adhesive tacks the trailing edges of the strips to extension sheet  24 . Extension sheet is also preferably made from paper stock. Again, once printing has been carried out, a user can then manually separate the strips from the extension sheet  24  prior to binding. The extension sheet  24  has a width about equal to that of support sheet  22  and a length such that the distance between the trailing edges  28 B,  32 B and  36 B of the binder strips and the trailing edge  24 B of the sheet is at least one inch, preferably approximately one and one-half inches. As will be explained in greater detail, the length of the extension sheet is dictated by the paper feed mechanism of conventional ink jet printers such as printer  44  of  FIG. 8 . 
     Note that extension sheet  24  further functions to receive printer overspray near the trailing edges  26 B,  30 B and  34 B of the binder strips. In addition, the regions on support sheet  22  located behind gaps  38  also receive printer overspray. Thus, ink is not deposited on the printer paper drive mechanism during the printing process. 
     In order to carry out the printing process, it is first necessary to configure the printer in the conventional manner to provide the desired graphics for the binder strips. 
     This can be done by first preparing a printing template that defines the boundaries of the three binder strips. The graphics themselves can readily be produced using readily available software such as Adobe Illustrator®. It is possible to configure the printer to provide the same or different graphics for each of the strips. 
     Referring to  FIG. 8 , once the printer, such as printer  44 , has been set up, the bookbinding structure  20  is inserted in the paper input of the printer, with the leading edge  22 A being fed first. The paper drive mechanism of the printer includes a first pair of pinch rollers  46 A and a second pair of pinch rollers  46 B which define part of a paper path through the printer as indicated by arrows  40 . A print head mechanism  50  is disposed over the paper path intermediate the pinch roller pairs, with a platen  48  being located below the path, under the print head mechanism.  FIG. 2  shows the bookbinding structure  20  after printing including exemplary graphics on each of the strips. Once the printing has been carried out, the three binder strips can be readily manually separated from sheets  22  and  24  and when used to bind a book. 
     A better appreciation of the subject bookbinding structure  20  can be provided in connection with the simplified schematic diagrams of FIG.  7 A/B/C.  FIG. 7A  shows one approach where a single support sheet  22  is used. One or more binder strips  26  are secured at opposite ends to the underlying sheet  22  by adhesive tacking as indicated by drawing elements  23 A/B. However, it is not usually possible to match the physical characteristics of the binder strips with the support sheet. Much of the difference is due to the presence of the adhesive on the strip  26  which reacts to moisture content differently than sheet  22 . This frequently causes the effective length of the strip to increase slightly after being tacked onto the support sheet. When the structure passes through the two pairs of pinch rollers  46 A and  46 B the leading edge  24 A is forced against sheet  22 . As the structure progresses along the paper path in the direction indicated by arrow  40 , the pinch rollers will eventually cause the strip to buckle up slightly in the region around the trailing edge  26 B of the strip due to the slight increase in the binder strip length. This buckling will frequently result in an unattractive smearing of the graphics in this region. 
       FIG. 7B  shows another approach where only the leading edge  26 A of the strip is attached to support sheet  22  by way of tacking  23 A. The remainder of the strip, including the trailing edge  26 B, is left free floating. Thus, any change in the binder strip  26  characteristic visa vie the support sheet will not create the strip buckling as previously described in connection with  FIG. 7A . However, in some cases when the trailing edge  26 B arrives at a location intermediate the pinch rollers as indicated by arrows  42 , the trailing edge may tend to curl up as shown in phantom designated by numeral  27 . Once again, this may result in smearing of the graphics near the trailing end of the strip. 
     Referring now to  FIG. 7C  which represents one embodiment of the present invention, as previously described, the leading edge of strip  26  is attached near a leading edge  22 A of the support sheet  22  by adhesive tack  28 A. The trailing edge of the strip is attached near the leading edge  24 A of the extension sheet  24 , with the length of the sheet being great enough to span the distance  42  between the pinch roller pairs. Thus, when the structure  20  is driven to the point the trailing edge of the strip is intermediate the pinch roller pair, extension sheet  24  will still be gripped by pinch roller pair  46 B ( FIG. 8A ) thereby preventing the trailing edge from curling up as depicted in  FIG. 7B . Further, since the extension sheet  24  is not connected to the support sheet  22 , other than by way of binder strip  26  (or by way of multiple binder strips), the trailing edge of the strip is free floating with respect to the leading edge so that any change in the binder strip characteristics after mounting on the sheets  22  and  24  does not result in graphic smearing as was the case previously described in connection with  FIG. 7A . Note that support sheet  22  should extend past the leading edge  24 A of the extension sheet  24  as shown in  FIG. 7C  to reduce the likelihood that the leading edge will get stuck in the drive mechanism. To this end, it is also preferable that the adhesive tack  28 B be located close to the leading edge  24 A of the sheet to reduce that likelihood that the leading edge will get caught in the drive mechanism. 
     Thus, a novel bookbinding structure has been disclosed. Although one embodiment has been described in some detail, it is to be understood that various changes can by made by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.