Abstract:
An adapter assembly for paper roll holders in a printer/plotter comprising ring shaped spacers that increase the diameter of the existing end mounted surfaces of the holder such that a larger size paper roll and be installed.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The invention relates to the field of printer/plotters and, in particular, to an adaptor system that allows a printer/plotter designed to use one size of paper roll to use a larger roll of paper.  
         [0003]     2. Description of Related Art  
         [0004]     A number of printer/plotters are designed to use only one size of paper roll. If high utilization of the printer/plotter occurs, there is an economic impact. For example, large capacity paper rolls (500 feet of paper) on a per foot cost basis can save 55 percent over 150 foot capacity rolls. Furthermore, loading a new paper roll is a somewhat time consuming operation.  
         [0005]     U.S. Pat. No. 5,911,382 Auxiliary Printing Media Roll Holder For Printer/Plotters by B Wilson discloses a paper roll holder adapted to hold a large paper roll that can be inserted in to a printer/plotter to replace the lower capacity holder. While this approach solves the problem it is an expensive piece of equipment and time consuming to install.  
         [0006]     Thus, it is a primary object of the invention to provide to provide a device that will allow a printer/plotter to utilize a larger capacity paper roll.  
         [0007]     It is another primary object of the invention to provide a device that will allow a printer/plotter to utilize a larger capacity paper roll that is easy to install.  
       SUMMARY OF THE INVENTION  
       [0008]     The invention is an adapter assembly for paper roll holders used in a printer/plotter that can only use a first size of paper roll and which allows the holder to accommodate a second larger size paper roll. The first paper roll includes a first tube having a first internal bore and the second paper roll includes a second internal bore. The paper roll holder of the printer/plotter includes spaced apart end members connected by a shaft. Each of the end members includes an external surface for mounting the ends of internal bore of the first size paper roll and incorporates a first retainer on the surface to prevent relative rotation there between. The adaptor system allows the second larger paper roll to be mounted to the holder. The adapter system consists of a spacer mountable to each of the spaced apart mounting members.  
         [0009]     In detail, each spacer includes a ring shaped spacer having an internal bore, the internal bore adapted to mate with the external surface of the end members of the holder and an external surface adapted to mate with the second internal bore of the second larger paper roll. A second retainer is provided for engaging the first retainer on the external surfaces of the end members. A third retainer is provided on the external surface of the cylindrical shaped member for engaging the second bore of the second larger paper roll. Preferably, a locking device is provided for securing the cylindrical shaped member to the end members.  
         [0010]     The first retainer is preferably first retainer are plurality of tapered triangular shaped protrusions; the second retainer is a plurality of tapered triangular shaped grooves, and the third retainer are also a plurality of tapered triangular shaped protrusions. An alternate version of the third retainer is a plurality of set screws space about the periphery of the cylindrical shaped member.  
         [0011]     Thus to install the spacers, all that is necessary is to remove one of the end members from the paper holder, remove the smaller paper roll and install a spacer on each end member of the holder and secure it thereto by means of the locking device. Thereafter, the second larger paper roll is installed such that one end engages the still attached end member with the second third retainer engaging the second roller and reinstalling the removed end member such that at it engages the other end of the second larger paper roll.  
         [0012]     The paper rolls all have a cardboard cylinder upon which the paper is rolled. Thus the first and third retainers engage and distort the cardboard as the rolls are installed preventing relative rotation there between.  
         [0013]     The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages thereof, will be better understood from the following description in connection with the accompanying drawings in which the presently preferred embodiments of the invention are illustrated by way of examples. It is to be expressly understood, however, that the drawings are for purposes of illustration and description only and are not intended as a definition of the limits of the invention.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]      FIG. 1  is a front view of a conventional prior art printer/plotter utilizing a small capacity paper roll.  
         [0015]      FIG. 2  is a cross-section view of the paper roll holder shown in  FIG. 1 .  
         [0016]      FIG. 3  is a cross-sectional view of the paper roll holder shown in  FIG. 2  illustrating the device used to engage the end of the paper roll.  
         [0017]      FIG. 4  is a cross-section view of the paper holder shown in  FIG. 2  with the spacer device, which allow the use of increased capacity paper rolls.  
         [0018]      FIG. 5  is an enlarged cross-sectional view of the spacer device shown in  FIG. 4 .  
         [0019]      FIG. 6  is an enlarged cross-sectional view of a second version of the spacer device. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0020]      FIGS. 1 and 2 , illustrate a typical prior art large capacity printer/plotter, generally referred to by numeral  10 . The printer/plotter  10  includes a housing  11  having a paper storage compartment  13  and a printing assembly  15 . As illustrated, the model shown is a Hewlett-Packard Corporation (HP) 1055CM. A paper roll  16 , having ends  17 A and  17 B is shown mounted on a holder  18  supported by the printer/plotter structure  19 . The paper roll  16  comprises paper  20  rolled up on a hollow cardboard tube  21  having an internal bore  22 . In operation, the paper  20  is unwound from the roll  16  and fed upward to printing assembly  15 .  
         [0021]     Referring to  FIGS. 2 and 3 , the holder  18  includes a shaft  23  having first and second ends  24 A and  24 B The end  24 A includes an end plate assembly  25  having a bore  26  there through mounted near the end  24 A of the shaft  23 . The end plates assembly  25  includes a disc shaped paper roll retainer  27  having a paper mounting member  28  that extends inward. The member  28  has an external surface  29  that includes three triangular shaped protrusions  30 A,  30 B and  30 C adapted to mate with the external bore  22  of the tube  21  of the paper roll  16 . A mounting bushing  32  extends outward from the end pate assembly  25  and incorporates a set screw  33  for securing the end plate assembly  25  to the shaft  23 .  
         [0022]     The mounted near the second end  24 B of the shaft  23  is a removable end plate assembly  33  having an internal bore  34  that slidably engages the shaft  23 . The end plate assembly  33  includes a second disc shaped paper roll retainer  35 . The assembly  33  further includes an inward facing mounting member  36 . The member  36  includes an external surface  37  having three triangular shaped protrusions  38 A,  38 B and  38 C (protrusions  38 B and  38 C are shown in  FIG. 5 ) adapted to mate with the internal bore  22  of the tube  21  of the paper roll  16 . A snap ring  42  is installed in a groove  43  in shaft  23  for securing the end plate assembly  34  in place. A coil spring  44  has one end  45  inserted into a hole  47  in the member  36  and a second end  48  installed in a hole  49  in the shaft  23 . This spring  44  bias the end plate assembly  34  to remain rotationally aligned with the shaft  23 .  
         [0023]     To secure the paper roll  16 , the end plate  34  is removed from the shaft  23 , the paper roll  16  is slid over the shaft until the end  17 A contacts the protrusions  30 A- 30 C on the surface  29  of the member  28  engage the bore  22  of the cardboard tube  21 . The roll  16  is pushed toward the end plate assembly  25 , which will cause the protrusions  30 A- 30 C to bite into the cardboard tube preventing differential rotation there between as the end  19 B abuts the disc  27 . The end plate assembly  33  is then installed on the shaft  23  and pushed toward the endplate assembly  25  until the protrusions  38 A- 38 C  38 C fully engage the cardboard tube  21 . The end  46  of the spring  44  is inserted into the hole  48 . The snap ring  42  is then installed into the groove  43  in the shaft  23  securing the roll  16  to the holder  18 . Note that the protrusions deform the soft cardboard of the tube  21  forming grooves therein. The completed assembly is then installed into the printer.  
         [0024]     Now such a design is limited to a single size paper roll. Referring to  FIGS. 4 and 5 , the subject invention is a roller adapter system that can be installed on the holder  18  to allow it to mount a paper roll  45  having a cardboard tube  46  with an internal bore  47  larger than the bore  22  of the cardboard tube  21  of the paper roll  16 . The adapter system includes a spacer  50 , which has a ring shape having an internal bore  52  adapted to slidably engage the surfaces  31  of the member  28 . The spacer  50  further includes three triangular shaped grooves  53 A,  53 B and  53 C adapted to mate with the protrusions  38 A- 38 C and the external surface  40  of the member  36 . The external surface  54  of the spacer  50  includes three equally spaced triangular shaped protrusions  56 A,  56 B and  56 C. The external diameter of the surface  54  is adapted to mate with the larger bore  47  of the tube  46 . A set screw  58  on the device allows it to be secured to either the member  28  or  36 . A second spacer  50  is installed on the external surface  29  of the member  28 , in an identical manner with the protrusions  38 A- 38 C mating with the grooves  53 A- 53 C.  
         [0025]     Installation is simple, which is accomplished removing the end plate assembly  34  and roll  16  from the shaft  23  and removing any paper roll  16 . Thereafter, a spacer  50  is installed on both the member  28  and  36  such that the grooves mate with the protrusions of the members  28  and  34  and secured thereto by the set screw  58 . Thereafter the larger size roll  45  can be installed as in the previous example.  
         [0026]     Referring to  FIG. 6 a  second version of the spacer, now indicated by numeral  50 ′, is identical except for the elimination of the external protrusions  56 A- 56 C. Here a series of screws  60  installed in threaded holes  62  are installed about the circumference of the external surface  54  can be individually adjusted to match any discrepancies in the internal bore the cardboard tube.  
         [0027]     Thus it can be seen that this simple spacer system can be used to allow the use of any size paper roll, the only limitation being the space within the printer/plotter. Additionally, while triangular shaped protrusions used by HP are typical, other methods are applicable and can be used with this invention.  
         [0028]     While the invention has been described with reference to particular embodiments, it should be understood that the embodiments are merely illustrative as there are numerous variations and modifications, which may be made by those skilled in the art. Thus, the invention is to be construed as being limited only by the spirit and scope of the appended claims.  
       INDUSTRIAL APPLICABILITY  
       [0029]     The invention has applicability to the printer/plotter manufacturing industry.