Patent Publication Number: US-2010119281-A1

Title: Cartridge Media Retention Mechanism

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application No. 61/113,124 filed Nov. 10, 2008, the disclosure of which is hereby incorporated by reference in entirety. 
    
    
     STATEMENT OF FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     This invention relates to cartridges for printers. In particular, this invention relates to retention mechanisms for preventing the undesired movement of media within the cartridge when the cartridge is not loaded in the printer. 
     Handheld printers are used for printing applications in which portability and mobility are important considerations. Many such handheld printers are designed to receive cartridges containing rolls of media. This media may be, for example, adhesive-backed labels for application to documents, packages, and the like. 
     Providing the media in cartridge form provides many benefits. One benefit is that the media can be protected inside of a cartridge housing. This reduces the risk of the media being damaged if the printer is mishandled or operated in a harsh environment. Another benefit is that the structure of the cartridge may improve the loading of the media into the printer. Typically, it is difficult for a user to manually thread the media between the print head and a platen roller, given the small size of most handheld printers and the tight confines into which the media would need to be loaded. The cartridge can be designed so that, during the loading of the cartridge into the printer, the media is automatically placed between the print head and platen roller. 
     However, storing the media in a cartridge also creates problems. Typically, the media in cartridges is coiled into a roll and a free end of the media extends from an exit end of the cartridge. If the free end is pulled into the cartridge, then it is usually inaccessible and the cartridge is rendered useless. Even if the free end remains outside the cartridge, it is possible that the media could be pulled out of any media guides that guide the free end of the media. If the free end is not guided properly past the print head and platen, then improper loading or feeding the media could jam the printer. 
     One solution to this problem has been to include a disposable adhesive transportation tab on the cartridge. This tab prevents the media in the cartridge from feeding forwards or backwards until the cartridge has been loaded in the printer and the tab has been removed. However, once the tab is removed, the cartridge must remain in the printer to maintain tension on the media. Hence, this solution does not accommodate the transfer of cartridges between printers or the switching of cartridges within a printer to change the type of media being printed on. 
     Another solution to this problem has been to provide a long path for the media within the cartridge to frictionally prevent the media from recoiling. However, having a long path increases the footprint of the cartridge and increases the force required to feed the media. This presents inefficiencies in feeding and marginalizes some of the benefit of reducing the size of the printer in the first instance. 
     Hence, a need exists for an improved way of preventing the movement of the free end of a length of media extending from a cartridge when the cartridge is not load in a printer. 
     SUMMARY OF THE INVENTION 
     A media cartridge is disclosed for use in a printer that prints onto the media. The media cartridge includes a cartridge housing having an exit passage. The media cartridge has a length of media with an end extending from the exit passage. The media cartridge further includes a retaining arm having a pinch position and an open position. In the pinch position, the retaining arm impinges on the media in the exit passage to inhibit passage of the media through the exit passage. In the open position, the retaining arm allows passage of the media through the exit passage. 
     According to one form of the media cartridge, a protrusion may extend outwardly from the cartridge housing. The protrusion may be engageable with an engagement structure on the printer to move the retaining arm from the pinch position to the open position when the media cartridge is loaded into the printer. The protrusion may be integrally formed with the retaining arm. The retaining arm may be separately formed from the cartridge housing. 
     According to another form of the media cartridge, when in the pinch position, the retaining arm and a portion of the cartridge housing may both contact the media. 
     According to yet another form of the media cartridge, when in the pinch position, the retaining arm may contact the media to convolute a path of the media. 
     A cartridge is also disclosed that has a media retention mechanism for use in a printer adapted to removably receive the cartridge. A cartridge housing contains a length of media. At least a portion of the length of media extends from an exit passage of the cartridge housing. A biasing mechanism biases a retaining arm part towards a portion of the cartridge housing. The media extends between the retaining arm part and the portion of the cartridge housing. 
     According to one aspect of the cartridge, the retaining arm part may have a pinch position in which the retaining arm part is driven toward the portion of the cartridge housing by the biasing mechanism to contact the media and an open position in which the retaining arm part is moved away from the portion of the cartridge housing to release the media. When the cartridge is inserted into the printer adapted to receive the cartridge, the protrusion on the retaining arm part may be actuated by the printer to move the retaining arm part to the open position. In the pinch position, the media may be pinched between the retaining arm part and the portion of the cartridge housing. In the pinch position, the media may be frictionally held in place by the retaining arm part and the portion of the cartridge. In the pinch position, the retaining arm part may contact the media to form a convoluted guide path for the media. 
     According to another aspect of the cartridge, the biasing mechanism may be a spring. 
     According to yet another aspect of the cartridge, the retaining arm part may be formed separately from the cartridge housing. The retaining arm part may be at least partially outside the cartridge housing. 
     According to one aspect of the cartridge, the cartridge may be for a thermal transfer printer. 
     According another aspect of the cartridge, the cartridge housing may comprise at least two case parts. 
     According to yet another aspect of the cartridge, the retaining arm part may be rotatable about an axis of rotation and the biasing mechanism may rotatably bias the retaining arm part towards a portion of the cartridge housing. 
     According to still another aspect of the cartridge, the cartridge includes media guides for guiding the length of media extending from the exit passage. 
     Thus, the disclosed media cartridge and associated retention mechanism provide an improved way of inhibiting the movement of a free end of a length of media when the cartridge is not loaded in a printer. Prior to the insertion of the cartridge in the printer or when the cartridge is removed from the printer, the retention mechanism inhibits the movement of the media. However, when the cartridge is inserted into the printer, the retention mechanism allows the media to be fed. With this design, the free end of the length of media is unlikely to recoil into the cartridge housing, rendering the cartridge unusable. Moreover, the retention mechanism helps to keep the end of the length of media in the media guides, so that during insertion of the cartridge into the printer, the media is properly threaded between the print head and the platen roller. This minimizes the risk of the media jamming during printing or feeding. 
     These and still other advantages of the invention will be apparent from the detailed description and drawings. What follows is merely a description of the preferred embodiments of the present invention. To assess the full scope of the invention, the claims should be looked to as the preferred embodiments are not intended to be the only embodiments within the scope of the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a handheld printer with a cartridge placed therein; 
         FIG. 2  is an exploded perspective view of the handheld printer of  FIG. 1  in which the cartridge is removed from the printer; 
         FIG. 3  is an exploded view of the cartridge; 
         FIG. 4  is a cross-sectional view of the cartridge with the retaining arm in the pinch position taken along line  4 - 4  of  FIG. 2 ; 
         FIG. 5  is a cross-sectional view of the cartridge in the printer in which the retaining arm has been moved to the open position by an engagement surface of the printer taken along line  5 - 5  of  FIG. 1 ; 
         FIG. 5A  is a detailed cross-sectional view of the interaction between the protrusion an the printer taken along line  5 A- 5 A of  FIG. 5 ; 
         FIG. 6  is a perspective view of the cartridge with the top housing removed to reveal and better show the exit passage of the cartridge; and 
         FIG. 7  is a perspective view of another embodiment of the cartridge in which the biasing mechanism is a spring in tension. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring first to  FIGS. 1 and 2 , a handheld printer  10  is shown. The handheld printer  10  has a body portion  12  and a head portion  14 . The body portion  12  includes a keypad  16  for entering data and operating the handheld printer  10 . On the lateral sides of the body portion  12  of the handheld printer  10  there are a pair of buttons  24 . Preferably, the pair of buttons  24  are located on opposing sides of the handheld printer  10  such that the pair of buttons  24  can be actuated towards the body portion  12  and, at the same time, towards one another (by a pinching motion). 
     The head portion  14  is adapted to receive a cartridge  18 . The cartridge  18  is removably received into a bay  22  in the head portion  14  of the handheld printer  10 . A rotating lock  23  on the handheld printer  10  is used to retain the cartridge  18  within the bay  22 . 
     Referring now to  FIGS. 3-6 , the various parts of the cartridge  18  can be seen. As best seen in  FIG. 3 , the cartridge  18  houses a roll  20  of printing media  40  such as, for example, adhesive-backed labels. The cartridge  18  further includes a cartridge housing  30  comprising a top housing  32  and a bottom housing  34  that are joined together. However, in other forms, the cartridge housing  30  may be a single piece or may include more than two pieces. The cartridge housing  30  supports the roll  20  and the various other internal parts of the cartridge  18  as will be described below. 
     In general, the cartridge  18  has two sides as viewed from the front of the handheld printer  10  when the cartridge  18  is loaded into the bay  22 . On a left side portion  36 , a spool  38  formed in the bottom housing  34  supports the roll  20  of printing media  40 . On a right side portion  42 , there are two spools  44  with an ink ribbon  46  spanning therebetween. The printing media  40  is wrapped about the spool  38  and a free end  48  of the printing media  40  extends from the roll  20  towards the right side portion  42  of the cartridge  18 . The free end  48  extends though an exit passage  50  located between the left side portion  36  and the right side portion  42 . 
     After passing through the exit passage  50 , the free end  48  then extends through media guides  52  on the far right side of the cartridge  18 . For a distance between the exit passage  50  and the media guides  52 , the free end  48  of the roll  20  and the ink ribbon  46  run substantially parallel to one another. 
     A guide tab  58  formed on the cartridge  18  extends for a portion of the length between the exit passage  50  and the media guides  52  prior to the thermal print head  54 . The guide tab  58  helps to define the path of the ink ribbon  46  as it passes between the two spools  44  and also guides the printing media  40  between the exit passage  50  and the media guides  52 . 
     As best seen in  FIG. 5 , when the cartridge  18  is received in the handheld printer  10 , a portion of the free end  48  of the printing media  40  and the ink ribbon  46  are threaded between a thermal print head  54  and a platen roller  56  as the printing media  40  extends from the exit passage  50  to the media guides  52 . In a gap between the end of the guide tab  58  and the media guides  52 , there is sufficient room for placement of the thermal print head  54  for printing on the printing media  40 . 
     The bottom of the cartridge  18  may also include an identification plate  60 . The identification plate  60  may have conductive surfaces which selectively provide electrical pathways to contacts in the bay  22  of the handheld printer  10 . Depending on the electrical connectivity of the contacts resulting from the electrical pathways formed by the identification plate  60 , different characterizing features of the cartridge  18  may be indicated to the handheld printer  10  (e.g., the type of media, the length of media, the type of ink, the compatibility of the cartridge with the printer, and so on). 
     Most notably, however, the cartridge  18  includes a retaining arm  62 . In the form shown, the retaining arm  62  includes a hub  64  that is rotatable about an axis of rotation A-A coaxial with the roll  20 . The hub  64  includes a protrusion  66  that extends outwardly from the cartridge housing  30 , a pinch finger  68 , and hub biasing surface  70  for engaging a biasing mechanism which is, in the form shown, a compression spring  72 . 
     The pinch finger  68  extends axially downward from a periphery of the hub  64  such that the pinch finger  68  forms a portion of the exit passage  50  along with a portion of the cartridge housing  30 . In the embodiment shown, the exit passage  50  for the printing media  40  is defined on one side by the pinch finger  68  and, on the other side, by an edge  74  of the bottom housing  34 . 
     The retaining arm  62  is biased toward a pinch position by the biasing mechanism (the spring  72 ). In the form shown, the spring  72  is compressed between the hub biasing surface  70  of the retaining arm  62  and a house biasing surface  76  of the top housing  32 . As the spring  72  attempts to expand, it drives the hub biasing surface  70  away from the housing biasing surface  76 . This, in turn, imposes a clockwise torque on the retaining arm  62  (as viewed from the front of the cartridge  18 ). This applied torque causes the pinch finger  68  of the retaining arm  62  to be driven toward the edge  74  of the bottom housing  34  thus “pinching” or impinging on the printing media  40  extending through the exit passage  50  between the cartridge housing  30  and the retaining arm  62 . 
     In the pinch position, the retaining arm  62  inhibits the passage of the printing media  40  through the exit passage  50 . The pinching frictionally captures the printing media  40  to inhibit the backwards feeding of the printing media  40  due to an uncoiling of the roll  20 . 
     Referring now to  FIG. 5 , during the loading of the cartridge  18  into the bay  22  of the handheld printer  10 , the protrusion  66  outside of the cartridge housing  30  engages a wall or other engagement structure of the handheld printer  10 . This engagement causes the rotation of the retaining arm  62  and the release of the free end  48  of the printing media  40 . 
     Preferably, As can be best seen in  FIG. 5A , the protrusion  66  has a tapered profile such that, during loading into handheld printer  10 , the protrusion  66  interferes a wall of the bay  22 . The tapered profile of the protrusion  66  causes the protrusion  66  to rotate as the protrusion  66  is wedged into the bay  22 . 
     The induced rotation of the retaining arm  62  during loading causes the retaining arm  62  to move to an open position. In the open position, the pinch finger  68  moves away or is separated from the edge  74  of the bottom housing  34 . This allows the printing media  40  to move through the exit passage  50  of the cartridge  18 . In this state, the printing media  40  may be pulled from the roll  20 , printed on, and fed through the discharge slot  26  of the handheld printer  10 . 
     After the printing media  40  has been fed through the discharge slot  26 , the pair of buttons  24  may be pressed to operate a cutting mechanism  28 . The cutting mechanism  28  cuts the printing media  40  to separate the portion of the printing media  40  extending from the discharge slot  26  of the handheld printer  10  from the rest of the roll  20 . 
     Thus, the cartridge  18  has a retention mechanism that selectively allows or inhibits the feeding of the printing media  40 . Whether or not feeding can occur is conditioned on whether the cartridge  18  is loaded into the handheld printer  10 . 
     When the cartridge  18  is not loaded in the handheld printer  10 , the retention mechanism is biased such that the feeding of printing media  40  is inhibited. This may be the case, for example, before the cartridge is put into use or after removing a partially used cartridge to put in another type of printing media. 
     Although the retaining arm  62  is shown pinching the printing media  40 , the retaining arm  62  could inhibit the movement of the printing media  40  in some other way. For example, the retaining arm  62  may convolute the guide path of the printing media  40  to make feeding more difficult. 
     Although the retaining arm has been shown as being formed separately from the cartridge housing, the retaining arm could also be integrally formed with at least a portion of the cartridge housing. In some forms, the biasing mechanism may be integrally formed with at least a part of the cartridge housing. If this is the case, the biasing mechanism could move from the pinch to open positions via elastic deformation. 
     Moreover, although the biasing mechanism has been shown as a compression spring, the biasing mechanism may take another form. For example, referring to  FIG. 7 , a tension spring  78 , is used to cause the retaining arm  62  to rotate toward the pinch position. 
     Further, although the retaining arm is shown as a rotatable hub having the projection and pinch finger, other forms of retaining arms are contemplated. For example, rather than rotation, the portion of the retaining arm that pinches or impinges upon the printing media may be actuated in a linear direction. Moreover, the retaining arm may be an assembly of various components instead of an integrally formed component. 
     Although the protrusion has been shown as having a tapered profile that interacts with the wall of the bay to move the cartridge from the pinch position to the open position during loading, other constructions and types of interactions between these components are contemplated. For example, the protrusion may have essentially vertical surfaces that interact with a ramped surface on the bay wall to move the protrusion, and thus the retaining arm, during loading. 
     While a roll of printing media  40  has been described above, the length of media could take of number of forms. For instance, the media could be folded back and forth over itself with the folds at lines of perforation. Regardless of the form of the supply of the media within the cartridge  18 , at least a portion of the length of media should extend though the exit passage  50  of the cartridge housing  30  for printing. 
     Many modifications and variations to these preferred embodiments will be apparent to those skilled in the art, which will be within the spirit and scope of the invention. Therefore, the invention should not be limited to the described embodiments. To ascertain the full scope of the invention, the following claims should be referenced. 
     INDUSTRIAL APPLICABILITY 
     The invention provides a cartridge with a retention mechanism for avoiding the reverse feeding of printing media when the cartridge is not loaded in a printer.