Abstract:
A holder for a rolled medium is provided. The holder has a mandrel having a drive surface adapted to receive the rolled medium and is adapted to be rotated so that an amount of rolled medium on the drive surface can be unrolled therefrom. A stop is located on a stop end of the drive surface. A retaining surface is located on a load end of the drive surface and is separated from the stop so that a rolled medium can be disposed therebetween with the retaining surface being movable between a first position where the retaining surface projects above the drive surface and a second position where the retaining surface does not project above the drive surface. A resilient biasing structure is joined to the retaining surface to drive the retaining surface toward the first position and the drive surface drives the rolled media toward the stop.

Description:
FIELD OF THE INVENTION 
   The present invention relates media holders for roll stored media such as paper, fabric, film, thermal donor media and thermal receiver media of the type that are used in home and commercial printers. 
   BACKGROUND OF THE INVENTION 
   Thermal printers are becoming an increasingly popular form of commercial and home printing. Such printers require precise alignment of media relative to a printing head throughout a printing operation. However, as media is driven through a thermal printing operation, a possibility arises that the lateral location of the medium on the holder will be adjusted and that registration problems can arise. Even minor registration problems can create unacceptable image artifacts in an image formed by a thermal printer. Accordingly, what is needed is a low cost mechanism to ensure that rolled mediums such as thermal donor or receiver mediums maintain a constant position on during printing operations. Similar considerations arise in other forms of rolled medium printing. 
   One approach to solve this problem is found in the Shinko Electric Company&#39;s model CHC-S7045 printer. In this printer, a holder assembly has a first flange that is retained to a spring-loaded steel shaft and a second removable flange that is located at a fixed position on a threaded end of the steel shaft using a wing nut, which is also threaded onto the shaft. Once the wing nut is unthreaded, the removable flange can be slid off of the steel shaft allowing rolled media to be placed over the steel shaft and interface with the spring-loaded flange remaining on the shaft. The removable flange is re-installed over the steel shaft and the wing nut is threaded onto the steel shaft. The wing nut to removable flange is then tightened to a prefixed location with regard to the edge of the steel shaft creating a fixed dimension from the end of the shaft to the inside flange of the removable flange to thereby constrain the rolled medium. 
   It will be appreciated, however, and that such approach requires manual threading and provides a fixed structure that is expensive and time consuming to load. 
   Thus, what is needed is a low cost system for retaining rolled medium on a mandrel that allows quick replacement of the rolled medium and that provides dynamic constraints to the control the positioning of the rolled medium. What is also needed is an effective and inexpensive system for warning a user when a medium is not located properly thereon. 
   SUMMARY OF THE INVENTION 
   In one aspect of the invention, a holder for rolled medium is provided. The holder has a mandrel with a drive surface adapted to receive the rolled medium and adapted to be rotated so that an amount of rolled medium on the drive surface can be unrolled therefrom. A stop is located on a stop end of the drive surface. A retaining surface is located on a load end of the drive surface and is separated from the stop so that a rolled medium can be disposed therebetween with the retaining surface being movable between a first position where the retaining surface projects above the drive surface and a second position where the retaining surface does not project above the drive surface. A resilient biasing structure is joined to the retaining surface and is elastically deformable, with the biasing structure storing potential energy when the retaining surface is driven to the second position and releasing the stored potential energy to urge the retaining surface to move to the first position. The retaining surface is positioned to engage a rolled medium positioned on the drive surface at a position between the first position and the second position and is shaped to transfer a portion of the stored potential energy in the resilient biasing structure to drive the rolled media toward the stop. 
   In another aspect of the invention, a holder for rolled media is provided. The holder has a mandrel defining a drive surface, the drive surface having a spring finger formed at a load edge thereof with the spring finger having a retaining surface extending outwardly from the drive surface when the spring finger positions the drive surface in a first position. The spring finger being elastically deformable from the first position to a second position wherein the retaining surface is positioned so that it does not extend outwardly from the drive surface. The spring finger is biased to move the retaining surface towards the first position. A stop is positioned at a stop end of the mandrel with the stop to block rolled media on the drive surface from lateral movement along the mandrel toward the stop end. The retaining surface is defined so that when the rolled media is loaded on the mandrel to a position proximate to the stop, the retaining surface engages the rolled media with the spring finger at a position between the first position and a second position, so that a portion of the force biasing the retaining surface from the second position to the first position is applied to drive the rolled media toward the stop. 
   In yet another aspect of the invention, a holder for a rolled medium is provided. The holder has a rolled medium drive surface for receiving the rolled medium; a stop means at a first end of the rolled medium drive surface and a retaining means at a second end of the drive surface. The retaining means is separated from the stop means by a distance defined by a width of the rolled medium, the retaining means being movable between a first position where the retaining means projects above the drive surface and a second position where the retaining means does not project above the contact surface. A biasing means is provided for biasing the retaining means from the second position to the first position. The retaining means has a translation means for converting the biasing from the biasing means into a force applied to urge the rolled medium toward the stop means. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  illustrates a perspective view of a first embodiment of a holder of the present invention; 
       FIG. 2  illustrates a side section view of the embodiment of  FIG. 1 ; 
       FIG. 3  illustrates an end view of a leading edge side of a rolled medium; 
       FIG. 4  illustrates another end view of a trailing edge side of a rolled medium; 
       FIG. 5  illustrates a holder with a retaining surface at a second position; 
       FIG. 6  illustrates a first portion of a loading process for loading rolled medium onto drive; 
       FIG. 7  illustrates a loading process as the rolled medium approaches a stop surface; 
       FIG. 8  illustrates an optional warning system in a warning condition; and 
       FIG. 9  illustrates the optional warning system of  FIG. 8  in a non-warning condition. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   In the embodiment illustrated in  FIGS. 1 and 2 , cylindrical mandrel  14  has an inner chamber  40 . As is shown in  FIG. 2 , chamber  18  is capped at a stop end  20  by a drive end cap  22 . Drive end cap  22  also has a stop end axle  24  that is aligned with a load end axle  26  on a load end cap  28  that is joined to cylindrical mandrel  14  at a load end  30  to provide pivot points to define an axis of rotation for cylindrical mandrel  14 . In the embodiment of  FIG. 1 , drive end cap  22  has an optional assembly drive gear  23  located thereon. Assembly drive gear  23  is adapted to receive co-designed gears of a drive system (not shown) within a printer (not shown) into which holder  10  is placed so that a driving force can be applied to cause cylindrical mandrel  14  and drive surface  12  to rotate about the axis of rotation. Drive end cap  22  also defines a stop surface  32  that is shaped to confront a rolled medium  16  that is inserted on to cylindrical mandrel  14  to limit axial movement of the rolled medium  16  toward stop end  20 . 
   Rolled medium  16  is typically provided in the form of a cylindrical core  34  having an outer surface  36  about which a medium  38  is wound. Medium  38  can comprise any form of material that can be used to donate or receive any type of material that can be transferred by way of a printer (not shown). In this regard, rolled medium  16  can comprise a thermal donor material that carries image forming materials including but not limited to dyes, pigments, inks, other colorants and/or protective materials that can be transferred from the donor onto a receiver by the application of force, energy, or other well known means. Medium  38  can also comprise receiver mediums that are adapted to receive dyes, pigments, inks, or other colorants from a donor medium or to receive inks or other materials from an inkjet, or contact printer. Medium  38  can also be of a type that is adapted to create contrast patterns when heat and/or other forms of energy are supplied thereto so that a thermal or other printer can record images thereon without applying a material such as a material from the donor medium or an ink. Medium  38  can also comprise other forms of receiver type mediums such as films, fabrics, papers and the like. 
   In the embodiment of rolled medium  16  shown in  FIGS. 2-4 , cylindrical core  34  has an inner chamber  40  that comprises an inner wall portion  42 . Inner wall portion  42  is sized and shaped to conform, generally, to the size and shape of drive surface  12  of cylindrical mandrel  14  so that drive surface  12  and inner wall portion  42  engage to cause rolled medium  16  and any medium  38  thereon to rotate generally in concert when holder  10  is installed in a printer and caused to rotate. As is further illustrated in  FIG. 3 , in this embodiment, inner wall portion  42  has one or more optional notch  44  therein that is adapted to engage one or more co-designed optional drive lugs  46  on drive surface  12  so that drive surface  12  and rolled medium  16  can rotate at a common rate. 
   As is also shown in  FIGS. 1 and 2 , a retaining surface  50  is provided proximate to load end  30  of drive surface  12 . Retaining surface  50  is separated from stop surface  32  at a distance that is generally consistent with the anticipated width of rolled medium  16 . Retaining surface  50  is movable between a first position where retaining surface  50  projects above drive surface  12  and a second position where retaining surface  50  does not project above drive surface  12 . 
   Retaining surface  50  is biased to move from the second position to the first position by a resilient biasing member  52 . Biasing member  52  is elastically deformable from an initial state to a set of deformed states whenever retaining surface  50  is driven from the first position to the second position. As this occurs, biasing member  52  stores potential energy. When retaining surface  50  is permitted to return, even partially, toward the first position, biasing member  52  releases the stored potential energy to urge retaining surface  50  to move toward the first position. This brings retaining surface  50  into contact with rolled medium  16  such as by contacting cylindrical inner core  34 . While biasing member  52  continues to drive retaining surface  50  toward the first position, retaining surface  50  is moved in a direction that is generally normal to drive surface  12 . However, the shape of retaining surface  50  translates a portion of the force urging retaining surface  50  in this direction into a force that urges inner core  34  toward stop end  20 . Typically, such a shape can comprise an arcurated, slanted, sloped or contoured shape adapted to translate force in one direction into a vector of the initial direction and a direction that drives rolled medium  16  toward stop surface  32 . 
   A detailed example of a loading process for the holder of  FIGS. 1-4  will now be described with reference to  FIGS. 5-7  which illustrate the interaction of retaining surface  50 , biasing member  52  and rolled medium  16 . In the embodiment of  FIGS. 1-7 , one embodiment of biasing member  52  is shown as a spring finger  54  that is integrally formed on drive surface  12  and that has retaining surface  50  provided thereon. To install a rolled medium  16 , spring finger  54  is moved against its bias from the first position illustrated in  FIGS. 1 and 2  toward a second position shown in  FIG. 5  at which retaining surface  50  is positioned below drive surface  12 . This allows any rolled medium  16  that is currently on drive surface  12  to be removed without interference from retaining surface  50  and also allows another rolled medium  16  to the inserted on to drive surface  12  without interference from retaining surface  50 . Such deflection can be manually induced or mechanically induced, for example by inserting an appropriate tool within inner chamber  40 . 
   In the embodiment of  FIGS. 1-7 , retaining surface  50  is adapted to facilitate such deflection during a first portion of a loading operation. As is illustrated in  FIG. 6 , in this embodiment, retaining surface  50  has a tapered loading portion  60  directed towards load end  30 . Tapered loading portion  60  is shaped so that as a rolled medium  16  is loaded onto drive surface  12  from load end  30  and is advanced toward stop end  20 , contact between a leading edge  62  of advancing rolled medium  16  and tapered loading portion  60  is translated into forces indicated by arrows in  FIG. 6  urging retaining surface  50  to the second position so that rolled medium  16  can be loaded onto drive surface  12 . 
   As leading edge  62  of inner core  34  or some other portion of rolled medium  16  contacts stop end  20 , a trailing edge  64  of inner core  34  begins to confront retaining surface  50 . This allows spring finger  54  to drive retaining surface  50  toward the first position. As rolled medium  16  is advanced along drive surface  12  toward stop surface  32 , a trailing edge  64  of inner core  34  engages retaining surface  50 . This prevents spring finger  54  from driving retaining surface  50  to the first position. As is shown in  FIG. 7 , the tapered sloping shape of retaining surface  50  translates such motion of retaining surface  50  in a direction  70  that is generally outward of drive surface  12  so that at least a part of the energy urging movement in direction  70  becomes a force that is applied against inner core  34  in a direction  72  that urges inner core  34  against stop surface  32  to position rolled medium  16 . As illustrated, in  FIG. 7  this occurs at a point where spring finger  54  has not returned retaining surface  50  to the first position. 
   It will be appreciated that this arrangement provides an initial advantage in helping to ensure that initial placement of rolled medium  16  on drive surface  12  is appropriate and that it also provides a further advantage after loading. Specifically, it will be appreciated that any forces that may be encountered during operation that tend to urge rolled medium  16  toward load end  30  and away from stop surface  32  will be resisted by the biasing force applied by resilient biasing member  52  such as spring finger  54  through retaining surface  50  to provide a dynamic adjustment system. 
     FIGS. 8 and 9  show another embodiment of the holder  10  of the present invention. In this embodiment, holder  10  has two retaining surfaces  50   a  and  50   b  and two resilient biasing members  52   a  and  52   b  illustrated as two spring fingers  54   a  and  54   b  located on opposite sides of drive surface  12 . It will be appreciated that in other embodiments, more than two retaining surfaces and resilient biasing members can be applied. 
   As is also shown in  FIGS. 8 and 9 , holder  10  is further adapted to provide a user with a warning signal that indicates the status of loading of a rolled medium  16  on the holder  10 . In this embodiment, a warning flag  80  is shown fixed to a load end cap  28 . Warning flag  80  comprises a center portion  82  joined to load end cap  28 . Center portion  82  is flanked by two flag projections  84  and  86  extending away from load end cap  28 . Flag projections  84  and  86  are associated with deflection surfaces  88  and  90  respectively. Warning flag  80  is elastically deformable in response to pressure applied against deflection surfaces  88  and  90  by movement of one of retaining surfaces  50   a  and  50   b , resilient biasing members  52   a  and  52   b , (shown as spring fingers  54   a  and  54   b ) tapered loading portion  60   a  and  60   b  during movement of resilient biasing members  52  between the first position and the second position. Warning flag  80  is shaped so that elastic deformation of the warning flag caused by contact with deflection surface  88  or  90  causes flag projection  84  or flag projection  86 , respectively, to move to a position indicating the extent of such contact which in turn is indication of the extent to which retaining surface  50  has moved away from the second position. As shown in  FIGS. 8 and 9  such projection causes flag projections  84  and  86  to extend outwardly from openings  92  and  94  in load end cap  28 . Such a warning flag  80  can be adapted to provide flag projections  84  and  86  that are movable between a warning position indicating that retaining surface  50  is not in a position for holding rolled medium  16  against stop surface  32 , and a position indicating that the retaining surface  50  is in a position for holding rolled medium  16  against the stop surface  32 . 
   It will be appreciated that while the above embodiments have illustrated a resilient biasing member  52  comprising a spring finger  54 , biasing member  52  can include other embodiments. For example, in other embodiments biasing member  52  can comprise at least one of a coil spring, a torsion spring, an air spring, a fluid spring, a combination of magnetic materials, a leaf spring, foams, fabrics or other materials that can be used to perform the function ascribed to resilient biasing member  52 . 
   The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention. 
   
     
       
             
           
             
             
             
           
         
             
                 
             
             
               PARTS LIST 
             
             
                 
             
           
           
             
                 
             
           
        
         
             
                 
               10 
               holder 
             
             
                 
               12 
               drive surface 
             
             
                 
               14 
               cylindrical mandrel 
             
             
                 
               16 
               rolled medium 
             
             
                 
               18 
               chamber 
             
             
                 
               20 
               stop end 
             
             
                 
               22 
               drive end cap 
             
             
                 
               23 
               assembly drive gear 
             
             
                 
               24 
               stop end axle 
             
             
                 
               26 
               load end axle 
             
             
                 
               28 
               load end cap 
             
             
                 
               30 
               load end 
             
             
                 
               32 
               stop surface 
             
             
                 
               34 
               cylindrical inner core 
             
             
                 
               36 
               outer surface 
             
             
                 
               38 
               medium 
             
             
                 
               40 
               inner chamber 
             
             
                 
               42 
               inner wall portion 
             
             
                 
               44 
               notch 
             
             
                 
               46 
               drive lugs 
             
             
                 
               50 
               retaining surface 
             
             
                 
               50a 
               retaining surface 
             
             
                 
               50b 
               retaining surface 
             
             
                 
               52 
               resilient biasing member 
             
             
                 
               52a 
               resilient biasing member 
             
             
                 
               52b 
               resilient biasing member 
             
             
                 
               54 
               spring finger 
             
             
                 
               54a 
               spring finger 
             
             
                 
               54b 
               spring finger 
             
             
                 
               60 
               loading portion 
             
             
                 
               60a 
               loading portion 
             
             
                 
               60b 
               loading portion 
             
             
                 
               62 
               leading edge 
             
             
                 
               64 
               trailing edge 
             
             
                 
               70 
               direction 
             
             
                 
               72 
               direction 
             
             
                 
               80 
               warning flag 
             
             
                 
               82 
               center portion 
             
             
                 
               84 
               flag projection 
             
             
                 
               86 
               flag projection 
             
             
                 
               88 
               deflection surface 
             
             
                 
               90 
               deflection surface 
             
             
                 
               92 
               openings 
             
             
                 
               94 
               openings