Patent Publication Number: US-8985730-B2

Title: Media processing device with enhanced media and ribbon loading and unloading features

Description:
BACKGROUND OF THE INVENTION 
     Various embodiments of the invention are directed to printers and other systems for processing media including labels, receipt media, cards, and the like. Applicant has identified a number of deficiencies and problems associated with the manufacture, use, and maintenance of conventional printers. Through applied effort, ingenuity, and innovation, Applicant has solved many of these identified problems by developing a solution that is embodied by the present invention, which is described in detail below. 
     BRIEF SUMMARY 
     Various embodiments of the present invention are directed to a system and method for applying pressure to a printhead of a printer. Example embodiments may provide a system that allows for pressure to be adjustable and variable along the length of the printhead. Such embodiments are configured to improve print quality by ensuring consistent printing along the length of a printhead. 
     Example embodiments of the present invention are directed to a printhead pressure adjustment assembly including a barrel configured to rotate about an axis and a biasing element received within the barrel and configured to apply a biasing force generally along the axis to a printhead. The biasing force applied to the printhead may be adjustable in response to the barrel being rotated. The assembly may further include a threaded insert received within the barrel, the threaded insert including external threads configured to engage reciprocally configured internal threads defined by the barrel to translate the threaded insert generally along the axis within the barrel in response to the barrel being rotated. The assembly may further include a cup received within the barrel and attached to the biasing element. A spring may be disposed between the threaded insert and the cup, where the spring is compressed in response to the barrel being rotated in a first direction and the spring is decompressed in response to the barrel being rotated in a second direction, opposite the first direction. 
     The printhead pressure adjustment assembly of some embodiments may further include a spring configured to be compressed between the biasing element and the threaded insert, where the spring applies the biasing force to the biasing element, where the spring is compressed in response to the barrel being rotated in a first direction, and the spring is decompressed in response to the barrel being rotated in a second direction, opposite the first direction. The biasing force may be increased in response to the spring being compressed and the biasing force may be decreased in response to the spring being decompressed. The adjustment assembly may be supported by a toggle assembly and the toggle assembly may be configured to be toggled between an engaged position and a disengaged position. The biasing force may be configured to be adjustable between about 3.5 pounds-force and about 9.3 pounds-force. The printhead pressure adjustment assembly of some embodiments may include a spring disposed within the barrel and configured to apply the biasing force to the biasing element. The barrel may include biasing force level demarcations arranged around a perimeter of the barrel for reference by a user during biasing force adjustment. 
     Embodiments of the present invention may include a printhead pressure adjustment assembly including a barrel defining an internally threaded bore, a threaded insert disposed within the barrel, where the threaded insert defines an external thread configured to engage the internally threaded bore of the barrel, a biasing element configured to apply a biasing force to a printhead, and a spring coupled to the threaded insert. The spring may be compressed, increasing the biasing force in response to the barrel being rotated in a first direction and the spring may be decompressed, decreasing the biasing force, in response to the barrel being rotated in a second direction, opposite the first direction. 
     According to some embodiments, the threaded insert may be configured to remain rotationally fixed as the barrel is rotated. The biasing force may be configured to be adjustable between about 3.5 pounds-force and about 9.3 pounds-force. The printhead pressure adjustment assembly may be configured to be rotated between an engaged position in which the biasing element is engaged with a printhead, and a disengaged position in which the biasing element is disengaged within the printhead. The printhead pressure adjustment assembly of some embodiments may include a base plate configured to retain the biasing element within the barrel in response to the printhead pressure adjustment assembly being moved to the disengaged position. Embodiments may include a friction element configured to provide a friction force to resist rotation of the barrel. The barrel may include an external rotation stop configured to limit rotation of the barrel to less than 360 degrees. 
     Embodiments of the present invention may include a printer including a printhead assembly and a printhead pressure adjustment assembly configured to apply pressure to the printhead assembly. The printhead pressure adjustment assembly may include an internally threaded barrel configured to rotate about an axis, wherein the barrel includes biasing pressure level demarcations arranged around a perimeter of the barrel. The printhead pressure adjustment assembly may further include a threaded insert including external threads that are configured to engage the internal threads of the barrel, a biasing element received within the barrel and configured to apply a biasing force generally along the axis to the printhead assembly, wherein the biasing force applied to the printhead is adjustable in response to the barrel being rotated, and a spring arranged to apply the biasing force to the biasing element. The spring of some embodiments may be compressed and the biasing force increased in response to the barrel being rotated in a first direction, and the spring may be decompressed and the biasing force is decreased in response to the barrel being rotated in a second direction, opposite the first direction. The printhead pressure adjustment assembly of some embodiments may be configured to toggle between an engaged position in which the printhead pressure adjustment assembly applies a pressure to the printhead assembly, and a disengaged position in which the printhead pressure adjustment assembly does not apply pressure to the printhead assembly. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
       Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein: 
         FIG. 1  illustrates a media processing device according to example embodiments of the present invention; 
         FIG. 2  illustrates a media processing device according to example embodiments of the present invention having an access door assembly disposed in a major support position; 
         FIG. 3  depicts a front view of the media processing device shown in  FIG. 2 , wherein the access door assembly is disposed in an operational position; 
         FIG. 4  depicts a front view of the media processing device shown in  FIG. 2 , wherein the access door assembly is disposed in transition between the operational position and the full support position; 
         FIG. 5  depicts a front view of the media processing device shown in  FIG. 2 , wherein the access door assembly is comprised of a major door and a minor door, and wherein the minor door is disposed in a minor support position; 
         FIG. 6  depicts a front view of the media processing device shown in  FIG. 2 , wherein the major door is disposed in a major support position, the minor door is disposed in the minor support position, and the access door assembly is disposed in the full support position; 
         FIG. 7  illustrates a side view of a media processing device according to example embodiments of the present invention wherein the access door assembly is disposed in the full support position; 
         FIG. 8  illustrates a detail view of a printing mechanism of a media processing device, taken along detail circle  8  of  FIG. 7 ; 
         FIG. 9A  illustrates a detail view of the printing mechanism of  FIG. 8 , wherein the printing mechanism is disposed in a printing position; 
         FIG. 9B  illustrates a detail view of the toggle assembly of  FIG. 9A ; 
         FIG. 9C  illustrates an exploded view of the toggle assembly of  FIG. 9B ; 
         FIG. 9D  illustrates a detail view of the toggle assembly of  FIG. 9A  including a section view of a barrel of the adjustment assembly; 
         FIG. 9E  is a detail view of the sectioned barrel of the adjustment assembly of  FIG. 9D  with the biasing element engaged with a printhead; 
         FIG. 9F  is a detail view of the sectioned barrel of the adjustment assembly of  FIG. 9D  with the biasing element engaged with a printhead and the threaded insert in a retracted position; 
         FIG. 10  illustrates a perspective detail view of the printing mechanism of  FIG. 8 , wherein the printing mechanism is disposed in the loading position; 
         FIG. 11  illustrates a perspective detail view of the printing mechanism of  FIG. 8 , wherein the printing mechanism is disposed in the printing position; 
         FIG. 12A  is a side view of a printhead assembly for a media processing device according to example embodiments of the present invention with a retention spring in a disengaged position; 
         FIG. 12B  is a side view of the printhead assembly of  FIG. 12A , wherein the retention spring in an engaged position; 
         FIG. 12C  is a top view of a retention spring structured according to example embodiments of the present invention; 
         FIG. 13  is a side view of the media processing device of  FIG. 7  with a roll of media installed; 
         FIG. 14  is a detail view of the printing mechanism of  FIG. 8 , wherein the printing mechanism is disposed in the loading position and ribbon has been installed; and 
         FIG. 15  is a detail view of the printing mechanism of  FIG. 14 , wherein the printing mechanism is disposed in the printing position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. Indeed, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout. 
     Printers and media processing devices may be configured to print and/or encode media drawn from a roll or spool. Such media may include a web supporting a plurality of individually cut media components, such as adhesive-backed and carrier-supported labels, or the media may be a continuous web such as a spool of linerless label media or direct thermal tag stock. Printers process (e.g., print, encode, etc.) the media by drawing the media from the spool and routing the media proximate various processing components (e.g., printhead, RFID reader/encoder, magnetic stripe reader/encoder etc.). Processing the media from a spool may facilitate a continuous or batch printing process. 
     From time to time, printers exhaust the available supply of media such that a user must replace the media supply spool. Other consumables such as ribbon, printheads, and the like must also be periodically replaced. Once such consumables have been replaced, it is important that they be positioned/routed efficiently and precisely to ensure limited downtime and proper print quality. 
     Embodiments of the present invention are directed to an improved media processing device that is structured to enhance user serviceability, simplify printhead alignment, and ease media routing. Such embodiments are configured to provide these advantages while maintaining a compact size footprint. 
       FIG. 1  illustrates a printer or processing device according to example embodiments of the present invention. While the illustrated embodiments and description provided herein are directed primarily to a printing device, other media processing devices such as media encoders or laminators, may benefit from the mechanisms described. Further, an example embodiment of the present invention may provide printing, encoding, and/or laminating functionality in a single device. 
     The printer  300  of  FIG. 1  includes a housing  301  and a base  303 . The housing  301  may include a front panel  330 , a rear panel  315 , a side panel  302 , and a support surface  310 . The housing may include a user interface  350  and a media exit  360 . The media exit may be arranged in the front panel  330  of the printer  300  and may be configured to expel media after it has been processed. The housing may further include an access door assembly  320  comprising a major door  322  and a minor door  324 . The major door  322  may be hingedly attached to the support surface  310  with hinges  340  and the minor door  324  may be hingedly attached to the major door  322 . The access door assembly  320  of  FIG. 1  is illustrated in the closed, operational position in which access to the internal components of the media processing device is precluded. In addition to keeping dirt, dust, and foreign objects from entering an internal cavity of the printer and potentially contaminating the consumables or the electronics of the processing device, the closed door may also reduce noise and prevent users from inadvertently touching sensitive components. 
     The major door  322  of the access door assembly  320  may pivot about hinges  340  through a range of approximately 180 degrees to a major support position to provide access to an interior cavity  306  of the printer as illustrated in  FIG. 2 . The hinges  340  may be located proximate a centerline of the housing  301  defined between the support surface  310  and the access door assembly  320 . Positioning the hinges  340  proximate a centerline of the housing  301  allows the access door assembly  320  to pivot about hinges  340  and achieve the major support position when the major door  322  comes to rest on the support surface  310 . Locating the hinges  340  proximate the centerline of the housing  301  further enables the side panel  302  of the printer to be situated against a surface, such as a wall or a cabinet, while still permitting the access door assembly  320  to achieve the major support position. The major door  322  may include at least a portion of the front panel  317  and/or a portion of the rear panel  319  to provide greater access to the interior cavity  306  when the major door is disposed in the major support position as will be described further below. In other embodiments, however, the major door  322  may include only a portion of the front panel. 
     The minor door  324  may be hingedly attached to the major door  322  and pivotable between an operational position (as shown in  FIG. 1 ) and a minor support position (as shown in  FIG. 2 ). In the operational position, the minor door  324  may be substantially co-planar with the access door assembly side  304  of the housing. In this operational position, the media processing device is ready for use and the internal cavity  306  is not accessible due to the position of the access door assembly  320 . Optionally, operation of the media processing device may be precluded when the access door assembly  320  is not in the operational position. As the major door  322  is rotated about hinges  340 , through a range of approximately 180 degrees, the minor door  324  pivots about hinges  323  through a range of approximately 90 degrees relative to the major door  322 . 
       FIGS. 3-6  illustrate a frontal view of a media processing device according to example embodiments of the present invention.  FIG. 3  illustrates the access door assembly  320  in an operational position where the minor door and at least a portion of the major door are generally coplanar.  FIG. 4  illustrates the access door assembly  320  in transition between the operational position and the major support position.  FIG. 5  illustrates the minor door  324  in the minor support position and the access door assembly  320  in transition between the operational position and the major support position. In the operational position, the back surface of the minor door faces the internal cavity  306  of the media processing device  300 . When disposed in the minor support position, the back surface of the minor door  324  rests against at least a portion of the major door  322 . In the illustrated embodiment, the major door includes a portion of the front surface  317  and the rear surface  319  (see  FIG. 2 ) upon which the minor door  322  rests in the minor support position. Optionally, should the major door  322  not include portions of the front surface  317  and rear surface  319 , the minor door may rest upon a stop or be supported by a maximum permitted rotation by the hinges  323  when in the minor support position. 
       FIG. 6  illustrates the access door assembly  320  in the major support position and the minor door  324  in the minor support position. A portion of the major door  322  may be supported by the support surface  310  of the media processing device when the major door  322  is rotated about hinges  340  about 180 degrees. This position is called the major support position. Further illustrated in  FIG. 6  is an imaginary plane  375  extending upwardly beyond the support surface  310 . The access door assembly  320  may be supported on the support surface without crossing the imaginary plane  375 , thereby allowing the side panel  302  of the printer  300  to be situated against a surface without hindering the opening of the access door assembly  320 . A portion of the major door may be substantially coplanar with the side panel when the major door is in the major support position illustrated in  FIG. 6 . 
     Referring back to  FIG. 2 , when the major door  322  is in the major support position, access to all of the necessary components to load and unload consumables (e.g., print media and printer ribbon) within internal cavity  306  is provided. Access to the internal cavity  306  is provided, at least partially, through at least three sides (e.g., the front side via a portion of the front panel  317 , the access door side and top side through the access door assembly  320 , and/or the rear side via a portion of the rear panel  319 ) which permit easier access and view of the internal components as will be described below. In other embodiments, the major door  322  may include only one, or possibly neither of a portion of the front panel  317  or the rear panel  319 . 
       FIG. 7  illustrates a side view of a printer according to example embodiments of the present invention with the major door  322  of the access door assembly  320  in the major support position exposing the internal cavity  306  and the printer chassis  308 . The printer chassis  308  is a structural member configured to support some or all of the internal components of the printer  300 . The internal components within the internal cavity  306  may include a media spindle  410 , a ribbon supply spindle  420 , and a ribbon take up spindle  430 . The media spindle  410  may be configured to hold a media spool (not shown) or media roll. The ribbon supply spindle  420  may be configured to hold a spool of the unused portion of a ribbon while the ribbon take-up spindle  430  may be configured to hold a spool of the used portion of the ribbon. Also illustrated is the media exit  360  through which printed media exits the printer  300 . The printer chassis  308  holds the media spindle  410 , ribbon supply and take-up spindles  420 ,  430 , and the printing mechanisms in place within the internal cavity  306 . 
     The printer chassis  308  may further hold a printing mechanism as shown in detail circle  8  which is further illustrated in  FIGS. 8 and 9A  depicting an enlarged view of the detail circle  8  of  FIG. 7 . The printing mechanism may include a printhead assembly  450  including a printhead  460 , a platen assembly  470  including a platen roller  480 , and a toggle assembly  440  including a toggle handle  442 , biasing element  446 , and a lift strap  448 . 
     The printhead assembly  450  is illustrated in a loading position in  FIG. 8  and a printing position in  FIG. 9A . The illustrated printing mechanism embodiment may be configured for thermal transfer printing wherein the printhead  460  and the platen roller  480 , when engaged, define a nip therebetween. A media substrate and a printer ribbon may be fed through the nip and the printhead may heat and compress the ribbon against the media substrate to deposit ink from the ribbon onto the media substrate. In the printing position, the printhead  460  engages platen roller  480  along a print line. 
     In the illustrated embodiment, the printhead assembly  450  of the printing mechanism is pivotally attached along axis  452  to the printer chassis  308 . The printhead assembly  450  includes the printhead  460  which is mounted to the printhead assembly with a retention spring mechanism as will be further detailed below. The toggle assembly  440  is pivotally attached to the printer chassis  308  and is configured to be manually rotated by a user via handle  442  between a disengaged position ( FIG. 8 ) and an engaged position ( FIG. 9A ). As the toggle assembly  440  is rotated from the disengaged position to the engaged position along arrow  444 , the biasing elements  446  bias the printhead assembly  450  into the printing position. The biasing elements  446  may include a curved profile configured to slidably engage a surface of the printhead assembly  450  as the toggle assembly  440  is rotated along arrow  444 . The curved profile of the biasing elements may provide a cam-type functionality which moves along the printhead assembly  450  as the toggle assembly  440  is rotated and drives the printhead assembly  450  into the printing position. Thus, the contact areas between the driving elements  446  and the printhead assembly  450  may be configured to allow a sliding motion as the toggle assembly is rotated to the engaged position. Detents within the toggle assembly  440  are configured to retain the toggle assembly in either the engaged position or the disengaged position. When the toggle assembly  440  is in the engaged position, the biasing elements  446  maintain pressure on the printhead assembly  450  in the printing position with the printhead  460  engaged with the platen roller  480 . In response to the toggle assembly being moved from the engaged position of  FIG. 9A  to the disengaged position of  FIG. 8 , the biasing elements  446  are disengaged from the printhead assembly  450  and the lift strap  448  is configured to raise the printhead assembly  450  out of the printing position and into the loading position. 
       FIG. 9B  illustrates the toggle assembly  440  of the printer that is configured with two adjustment assemblies  447  adapted to support the biasing elements  446 . Each adjustment assembly  447  may be configured to vary the pressure applied to the printhead assembly  450  through its corresponding biasing element  446 . As the pressure between the printhead and the platen roller  480  plays a critical role in print quality, it is important to maintain a selected pressure across the printhead based upon, among other things, the media that is being printed and the printhead characteristics. Example embodiments of the present invention may be configured to apply pressure to the printhead assembly  450 , where the pressure is variable between a minimum and a maximum level and where a user may adjust the pressure to numerous values within this range. For example, each biasing element may be adjustable, by the adjustment assembly to exert a force of between about 3.5 pounds-force and 9.3 pounds-force. 
       FIG. 9C  illustrates an exploded view of the toggle assembly  440  including the two adjustment assemblies  447  and associated biasing elements  446 . The toggle assembly may include a toggle bar  710  that is connected to a base plate  720 . The toggle bar  710  may be connected to the base plate  720  in a variety of manners; for example, the illustrated embodiment includes interlocking tabs  725  of the base member that engage corresponding recesses  715  in the toggle bar  710 . 
     The adjustment assemblies  447  may include a barrel  730  that is disposed between the toggle bar  710  and the base plate  720 . The barrel  730  is rotatable along its longitudinal axis relative to the toggle bar  710  as will be further detailed below. Within the barrel  730  are housed a spring  750 , a threaded insert  740 , a cup  760 , and a corresponding biasing element  446 . 
     The biasing element  446  may define a non-circular shape, such as a hexagon, that is configured to engage a correspondingly shaped hole  722  in the base plate  720  to preclude rotation between the biasing element  446  and the base plate  720 . 
     The cup  760  may be integrally formed with the biasing element  446  or otherwise attached to the biasing element  446  such that the cup  760  and the biasing element  446  are fixed relative to one another. In this regard, the cup  760  and the biasing element  446  may be rotationally fixed relative to the base plate  720 . However, as will be further detailed below, the biasing element  446  may move axially (generally along the longitudinal axis of the barrel  730 ) within the hole  722  of the base plate  720 . 
     The threaded insert  740  of the adjustment assembly  447  may define an external thread, such as a double-start ACME thread. The threaded insert  740  may be received within the barrel  730 , which defines a reciprocally configured mating thread that is structured to engage the external threads of the threaded insert  740 . The threaded insert  740  may further define an internal channel  745  that is configured to receive the biasing element  446  there through. The internal channel  745  of the threaded insert  740  may define a shape corresponding to the non-circular shape of the biasing element  446  to maintain the threaded insert  740  in fixed rotational alignment with the biasing element  446  (e.g., if the biasing element were hexagonal then the threaded insert  740  may define a hexagonal bore). 
     A spring  750  may be captured between the threaded insert  740  and the cup  760  where the biasing element  446  passes through the spring  750 . When assembled, the threaded insert  740  may engage one end of the spring  750  while the other end of the spring  750  is engaged within the cup  760 . 
       FIG. 9D  is a partial section view of the assembled toggle assembly  440  to better illustrate the assembled internal components of an example adjustment assembly  447 . In the depicted embodiment, the external threads of the threaded insert  740  engage the internal threads of the barrel  730  and the spring  750  is held between the threaded insert  740  and the cup  760 . The cup  760  is shown seated on the base member  720  with the biasing element  446  protruding through the opening in the base member  720 . As cup  760  is integrally formed with the biasing element  446  or otherwise secured thereto, when the cup  760  is seated against the base member  720  as shown, the biasing element  446  extends through the hole in the base member  720  while being retained by the cup  760 . 
     When the toggle assembly  440  engages the printhead assembly  450  as illustrated in  FIG. 9A , the printhead assembly  450  presses against the biasing element  446  along arrow  780 . As depicted in  FIG. 9E , which illustrates a detail view of the sectioned adjustment assembly of  FIG. 9D , the printhead assembly  450  pressing against biasing element  446  causes the cup  760  to rise off of the base member  720 , thereby compressing the spring  750 , such that the spring  750  applies a force to the biasing element  446 , which is transmitted through the biasing element  446  to the printhead assembly  450  in the direction of arrow  785 . 
     The biasing force applied or transmitted by the biasing element  446  to the printhead assembly  450  may be adjusted by rotating the barrel  730  of the adjustment assembly  447 . Rotation of the barrel  730  about an axis along which the biasing force is applied in a first direction (e.g., clockwise) may cause the threaded insert  740  to retract toward the toggle bar  710 . As the threaded insert  740  is rotationally fixed by the biasing element  446 , which his rotationally fixed by the base member  720 , rotation of the barrel  730  causes the internal thread of the barrel  730  to turn relative to the threaded insert  740 , which results in the threaded insert  740  advancing or retracting within the barrel  730  depending upon the direction of rotation of the barrel  730 . Rotation of the barrel in a second direction (e.g., counter-clockwise) may cause the threaded insert  740  to advance toward the base member  720 .  FIG. 9F  illustrates the sectioned adjustment assembly of  FIG. 9D  with the threaded insert  740  in a retracted position, toward the toggle bar  710 . As depicted, the spring  750  is less compressed than the illustrated embodiment of  FIG. 9E , thereby exerting a lower force on the biasing element  446  against the printhead assembly  450 . The spring  750  is decompressed in response to the threaded insert  740  being retracted toward the toggle bar  710 . 
     As will be appreciated by one of skill in the art in view of this disclosure, movement of the threaded insert  740  within the barrel  730  may compress or decompress the spring  750  between the threaded insert  740  and the cup  760 . In order to increase the biasing force exerted by the biasing element  446  on the printhead assembly  450 , the spring may be compressed by turning the barrel  730  in order to advance the threaded insert  740  in a direction opposite arrow  780  of  FIG. 9D . In order to decrease the force exerted by the biasing element  446  on the printhead assembly  450 , the spring may be decompressed by turning the barrel  730  in order to retract the threaded insert  740  in the direction of arrow  780 . 
     In some embodiments, rotation of the barrel  730  may be limited to define a maximum biasing force and a minimum biasing force for any given spring that is used. The maximum biasing force being exerted when the spring is at a first level of compression (e.g., a relatively high level of compression) permitted by rotation of the barrel  730  and the minimum biasing force being exerted when the spring is at a second level of compression (e.g., a relatively low level of compression) permitted by rotation of the barrel. The limitation of rotation of the barrel  730  may be achieved, for example, as illustrated in  FIG. 9C , by an external protrusion  734  defined by barrel  730 , which is configured to engage a protrusion  724  defined by the base member  720 . Such a rotation limitation feature may allow, for example, 270 degrees of rotation of the barrel. The amount of rotation, combined with the pitch of the threads (both internally on the barrel  730  and externally on the threaded insert  740 ), may dictate the travel of the threaded insert  740  within the barrel  730 . For example, a thread pitch of six threads-per-inch, combined with a maximum rotation limit of 270 degrees may combine to allow the threaded insert to travel ⅛ th  of an inch from maximum compression to maximum decompression of the spring  750 . 
     The position of the threaded insert  740  within the barrel  730  may correlate with the biasing force applied by the spring  750 ; however, it is appreciated that in an example embodiment in which the cup  760  is resting on base member  720 , and the spring  750  is fully decompressed, rotation of the barrel  730  to further reduce the biasing force would have no effect. Similarly, when the threaded insert  740  is rotated to the fully advanced position, further advancing of the threaded insert  740  may be precluded by the termination of the internal threads of the barrel  730 , or the threaded insert  740  may be in contact with the cup  760 , thereby preventing further compression of the spring  750 . In such an embodiment, the biasing force may not be further increased by rotation of the barrel. 
     The range of force available to be exerted by the biasing element  446  on the printhead assembly  450  may also be a factor for spring  750  selection. For example, to achieve a minimum biasing force of 3.5 pounds-force and a maximum of 9.3 pounds-force, with a maximum threaded insert travel of ⅛ th  of an inch, a spring  750  may be selected that is configured to provide 3.5 pounds-force at a compression of 1/16 th  of an inch and provide 9.3 pounds-force at a compression of 3/16 th  of an inch. As in the aforementioned example, it may be desirable to maintain a spring force on the biasing element  446  even under the minimum biasing force. Maintaining the spring in compression may be desirable such that the cup  760  is biased into engagement with the base member  720 , even when the toggle mechanism  440  is moved to the disengaged position and there is no resistive force pressing against the biasing element  446 . Maintaining the engagement between the cup  760  and the base member  720  applies a spring force to the threaded insert  740  thereby applying a pressure between the threads of the threaded insert  740  and the internal threads of the barrel  730  The pressure between the threads of the threaded insert  740  and the barrel  730  results in an increase in friction between the barrel  730  and the threaded insert  740  which may serve as a “barrel break” to reduce accidental or unintended rotation of the barrel  730  when the toggle assembly  440  is in the disengaged position or moved between the engaged and the disengaged positions. 
     The amount of force applied by the biasing elements  446  against the printhead assembly  450  may be measured, for example, as the amount of force required to initially raise the cup  760  off of the base member  720 . Optionally, the printhead assembly  450  may be arranged such that when the toggle assembly  440  is in engaged with the printhead assembly  450 , the biasing elements  446  are configured to be depressed within the adjustment assemblies  447  to a predefined depression. This predefined depression (e.g., 1/16 th  of an inch) may be the point at which the force of the biasing elements  446  is measured. 
     Another mechanism by which unintended rotation of the barrel may be deterred is by increasing the friction between the barrel and the toggle bar  710 . The barrel  730  may be received by a collar  712  of the toggle bar and the adjustment assembly  447  is held between the collar  712  and the base member  720 . An  0 -ring, such as a silicone  0 -ring, may be received within a recess in the collar  712  and/or in the barrel  730 . The  0 -ring may provide additional friction between the collar  712  and the barrel  730  such that unintended rotation of the barrel  730  is deterred. While unintended rotation of the barrel  730  is undesirable, an unnecessarily high level of friction between the barrel and toggle bar  710  may be undesirable as a user must be able to manually turn the barrel  730  to adjust the biasing force. Therefore, the force required to turn the barrel  730  may be high enough to deter unintended rotation, but low enough to allow a user to easily rotate the barrel  730 . To aid a user in rotation of the barrel, the barrel  730 , or a portion thereof, may be coated with a soft-touch or higher friction material (e.g., rubber) that enables a user to more easily turn the barrel  730 , possibly with the use of a single finger. 
     The barrel  730  may be configured with demarcations  732 ,  733  around the exterior of the barrel, as shown in  FIG. 9B . The demarcations may be indicative of the biasing force level of the adjustment assembly  447 . A stationary mark may be located on the toggle bar  710  or the base member  720  such that alignment between the stationary mark and the demarcations  732 ,  733  may indicate the biasing force level. Optionally, the demarcations may be arranged to face a particularly visible direction as an indication of the biasing force level. A single bar, as illustrated at  733 , may be indicative of the lowest biasing force level (i.e., the threaded insert  740  is fully retracted within the barrel, towards the toggle bar  710 ), while four bars, as illustrated at  732 , may be indicative of the highest force level (i.e., the threaded insert  740  is fully advanced within the barrel, away from toggle bar  710 ). While the illustrated demarcations are a series of lines, any series of demarcations may be used that convey an increasing level of biasing force. Smaller demarcations  731  may also be provided between the larger demarcations  732 ,  733  to provide reference marks for users to reference during adjustment. 
     As printhead and material characteristics may be variable, the biasing force of each of the adjustment assemblies  447  may be independently adjusted, and the appropriate biasing force for optimum print quality may be different between the adjustment assemblies. 
     As previously outlined, the toggle assembly  440  may be configured to lift the printhead assembly  450  from the printing position to the loading position. The lift strap  448  may be attached at one end to the toggle assembly  440  and at the other end to the printhead assembly  450 . The lift strap  448  may be made of any flexible, high-tensile strength material with low elasticity, but is preferably a polyester film. In response to the toggle assembly  440  being moved from the engaged position of  FIG. 9A  to the disengaged position of  FIG. 8 , the toggle assembly  440  lifts the lift strap  448  to raise the printhead assembly  450  from the printing position to the loading position. Further, the lift strap  448  suspends the printhead assembly  450  in the loading position while the toggle assembly  440  is in the disengaged position. 
       FIGS. 10 and 11  illustrate perspective views of the print mechanism in the loading position and the printing position respectively. As illustrated, in the loading position of  FIG. 10 , the printhead assembly  450  is raised away from the platen roller  480  and platen assembly. The platen assembly includes forks  475  projecting upwardly from the platen assembly and configured to engage the printhead assembly  450 . The forks  475  are configured with a bevel disposed on their inward-facing sides arranged to receive a corresponding tab  455  from the printhead assembly  450 . The tab  455  engages the forks  475  to align the printhead  460  with the platen roller  480 . The forks  475  align the printhead  460  to the platen roller  480  to achieve the optimum print-line location between the components. Proper alignment results in higher quality printing. As the printhead assembly  450  is moved from the loading position to the printing position, the forks  475  engage the tabs  455  of the printhead  460  to adjust the location of the printhead  460  relative to the platen roller  480  to achieve proper alignment. 
     Example embodiments of the present invention may provide a quick-release printhead attachment mechanism whereby the printhead  560  is secured to the printhead assembly  550 .  FIG. 12A  depicts a printhead assembly  550  including a printhead  560 . The printhead  560  may include one or more studs  562  extending from the back of the printhead  560 . The studs  562  include a relatively large diameter head  564  with a relatively small diameter stem  566 . The printhead  560  is configured to be securely attached to the printhead assembly  550  by inserting the studs  562  through a respective through hole in the printhead assembly  550  and through a respective keyhole  572  in a retention spring  570  when the retention spring is in the unlocked position depicted in  FIG. 12A . An example embodiment of the top view of a retention spring is illustrated in  FIG. 12C  including the keyhole  572  with a keyway  574 . Once the studs  562  of the printhead  560  are inserted through the printhead assembly  550  and the keyhole  572  of the retention spring  570 , the retention spring  570  may be slid in the direction of arrow  600  to a locked position as illustrated in  FIG. 12B . 
     In response to the retention spring  570  being slid in the direction of arrow  600 , the stud  562  slides from keyhole  572  to keyway  574 . The head  564  of the stud  562  is configured to be a greater diameter than the width of the keyway  574  such that the stud cannot be removed from the printhead assembly  550  as the stud head  564  will not pass through the keyway  574  of the retention spring  570 . As the retention spring  570  is moved in the direction of arrow  600 , the head  564  of the stud  562  is engaged by an arcuate portion  576  of the retention spring  570 . The arcuate portion  576  drives the head  564  of the stud  562  in an upward direction relative to the printhead assembly  550 , thereby drawing the printhead  560  into a secured position on the printhead assembly  550 . The retention spring  570  maintains the printhead  560  in the secured position as the arcuate portion  576  in its relaxed state is of greater height than the height of the stud head  564  in the secured position. The resultant deformation of the arcuate portion  576  maintains tension on the stud  562 , thereby holding the printhead  560  securely in position on the printhead assembly  550 . 
     Removal of the printhead  560  from the printhead assembly  550  may be performed by sliding the retention spring  570  in a direction opposite arrow  600 , disengaging the arcuate portion  576  from the stud  562  and allowing the stud head  564  to pass through the keyhole  572  and the through-hole through the printhead assembly  550 . 
     Before a printing operation may begin, the print media must be loaded into the printer.  FIG. 13  illustrates the printer of  FIG. 7  with a media roll  610  loaded on the media spindle  410 . The illustrated embodiment includes a media spindle alignment feature  412 , a media guide  414 , and a media sensor  416 . The alignment feature  412  that may fold or rotate to a loading position, whereby a media roll  610  may be loaded onto the media spindle  410 , and subsequently, the alignment feature  412  may fold or rotate back into engagement with the media roll  610  to maintain the media roll  610  in the proper position on the media spindle  410 . The media web  612  may extend from the media roll, through one or more guiding features, to the printing mechanism and/or other processing components. In the illustrated embodiment, the media web  612  extends from the media roll  610 , around the media guide  414  and past the media sensor  416  to arrive at the printhead assembly  450 . 
     The media sensor  416  may provide a signal to the printer electronics when the media web is present which may allow the printer to determine when printing may occur. The media sensor may be configured to read or otherwise sense the transition or delineation between individual media elements on the media web  612  to enable alignment of the image printed at the print line of the printhead  460  relative to the edges of the media element. The media web  612  may extend along the printhead assembly  450 , between the nip defined by the printhead  460  and the platen roller  480 , and out through the media exit  360 . As illustrated, when the printhead assembly  450  is disengaged from the platen roller  480 , a loading gap  660  is created between the printhead  460  and the platen roller  480  which allows a user to more easily feed the media web  612  from the media roll  610 , past the media sensor  416 , and through the print mechanism to the media exit  360 . Conventionally, if the printhead  460  does not disengage from the platen roller  480 , the structure of the platen/printhead nip can present a conflict in that tight tolerances between the printhead  460  and the platen  480  assist in printing, but such tolerances may make it difficult for a user to insert the print media web  612  between the printhead  460  and the platen  480  during loading of the print media web  612  into the printer  300 . 
     Example embodiments of the present invention may allow simplified media loading as described above; however, example embodiments may further provide for simplified ribbon loading as described herein. Thermal transfer printers use an ink ribbon that contains ink disposed on a substrate, where the ink is transferred to a media substrate via pressure and heat. Media processing devices according to example embodiments of the present invention may use any number of types of ribbons including dye ribbons, hologram ribbons, security material ribbons, and UV coating ribbons, among others. Therefore, in addition to the media substrate being loaded and aligned between the printhead assembly  450  and the platen roller  480 , the ink ribbon  640  must be similarly inserted between the printhead  460  and the platen roller  480 .  FIG. 14  illustrates the printing mechanism of  FIG. 8  with a printer ribbon installed. The ink ribbon  640  includes a supply spool  620  and a take-up spool  630 , each disposed on a respective spindle. The ink ribbon  640  is fed along an ink ribbon path extending from the supply spool  620 , around the printhead assembly  450 , past the printhead  460 . The ink ribbon  640  makes a relatively sharp upward transition after the printhead  460  toward the toggle assembly  440 , around which the ink ribbon bends to arrive at the take-up spool  630 . The relatively sharp transition after the printhead  460  provides a peel-mechanism whereby the ink ribbon is lifted from the media substrate at a sharp angle to reduce the flash or excess ink that may surround a printed image. 
       FIG. 14  illustrates the ink ribbon  640  installed onto the print mechanism and properly routed past the printhead  460 . As illustrated, the loading gap created  660  when the printhead assembly  450  is disengaged from the platen roller  480  allows the ribbon  640  to be easily routed and aligned to the printhead assembly  450 .  FIG. 15  illustrates the ink ribbon  640  as installed with the printhead assembly  450  in the engaged position. As depicted, the path from the supply spool  620  to the take up spool  630  is longer when the printhead assembly  450  is in the printing position such that when the toggle assembly  440  is moved from the loading position to the printing position, tension is applied to the ink ribbon  640 . The tension applied to the ink ribbon  640  is desirable and ensures that the ink ribbon  640  lays flat against the printhead  460 . Further, the tension applied to the ink ribbon  640  provides more consistent and repeatable alignment of the ribbon. 
     As will be apparent to one of ordinary skill in the art in view of this disclosure, print media and ink ribbon may be loaded and fed with greater ease and flexibility by incorporating one or more structures herein discussed. 
     Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.