Abstract:
A portable printer having improved ergonomic and operational characteristics. The printer includes an asymmetrically-damped media centering mechanism having first and second media support members moveable along a common longitudinal axis and configured to grasp roll media. The media support members are coupled to a reciprocal movement mechanism configured to translate a longitudinal movement of the first media support member into a corresponding opposite longitudinal movement of the second media support member. A pivoting arm is coupled to the reciprocal movement mechanism. The pivoting arm pivots to a first position when the first and second media support members are moved closer to each other, which causes a damping gear to engage the reciprocal movement mechanism, thereby damping the grasping motion of the media support members and providing an improved user experience. The printer facilitates one-handed operation, including one-handed loading and unloading of media, enabling its use in a variety of environments.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is a divisional application of pending U.S. patent application Ser. No. 12/904,467, filed Oct. 14, 2010, which application claims priority from, and the benefit of, U.S. Provisional Application Ser. No. 61/304,964, filed Feb. 16, 2010, the contents of each of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     The present disclosure relates to continuous feed printers, and more particularly, to a portable label or thermal printer having a selectively adjustable, asymmetrically damped media centering assembly. 
     Portable or desktop printers are often used in commercial settings, e.g., in warehouses, in industrial and manufacturing environments, by shipping services, in vending machine routes, in the vending and gaming industries, and in retail establishments for ticket printing and inventory control. Ideally, portable printers weigh only a few pounds and are small enough to be easily carried during use and/or easily attached to a buckle or a harness-type device. This enables the user to print labels or receipts on demand without having to retrieve a printed label from a printing station. Because the printer is portable, the printer may include a power source, such as a disposable or rechargeable battery, and may additionally communicate with a host terminal or network connection via a wireless interface, such as a radio or optical interface. A portable printer may utilize sheet-fed media, or, more popularly, continuous-feed media, e.g., rolls of paper, labels, tags, and the like. Portable printers commonly employ direct thermal transfer techniques, whereby thermochromic media passes over a thermal print head which selectively heats areas of the media to create a visible image. Also popular are thermal transfer printers which employ a heat-sensitive ribbon to transfer images to media. 
     A continuous feed printer is particularly suitable for printing onto stock material which may include, but is not necessarily limited to, labels, receipts, item labels, shelf labels/tags, ticket stubs, stickers, hang tags, price stickers, and the like. Label printers may incorporate a media supply of “peel away” labels adhered to a coated substrate wound in a rolled configuration. Alternatively, a media supply may include a plain paper roll suitable for ink-based or toner-based printing. Continuous media is typically supplied in rolls, and is available in a wide range of widths. The roll media may be wound around a generally tubular core which supports the roll media. The core may have a standard size, or arbitrarily-sized inner diameter. In use, the media is drawn against a printing head, which, in turn, causes images to be created on the media stock by, e.g., impact printing (dot matrix, belt printing), by localized heating (thermal transfer printing), inkjet printing, toner-based printing, or other suitable printing methods. 
     Portable or thermal printers may be designed for use with one type of printing media or one particular size of print media, e.g., 2-inch label stock or 3-inch label stock. Other portable printers may be configurable to accommodate different media types and sizes. Such printers may include a media centering mechanism which is designed to accommodate roll media of varying widths and/or core diameters. The media centering mechanism may include opposing support members configured to engage the media roll core. A media centering mechanism typically includes first and second support members that are generally biased towards each other to secure the media roll. Movement of the first and second support members may be synchronized by one or more gears or belts such that, when a support member is moved a distance from the centerline of the media roll, the other support member moves a corresponding distance in the opposing direction from the centerline of the media roll. 
     Many of the media centering mechanisms associated with portable printers are not particularly versatile or convenient to use, and may employ various spring-loaded elements that are intended to accommodate media of various types and sizes. As a result, even though certain portable printers may accommodate media of various sizes, to load such media a user must manipulate the spring-loaded members and other mechanical elements using both hands. Such spring-loaded elements can suddenly snap into position with considerable force, which may result in an unpleasant user experience, damage to the print media, and even damage to the printer itself. 
     SUMMARY 
     The present disclosure is directed to a portable printer having an asymmetrically-damped media centering mechanism. The mechanism allows a user to open the spring-loaded media support members with ease, but, upon release, damping is provided to the media support members to cause the retraction thereof to occur at slower, controlled rate. In this manner, the disclosed media centering mechanism may facilitate easier media loading (including one-handed loading), may provide an improved user experience, and may prevent damage to the print media and/or to the printer. 
     The dampening mechanism includes a damping gear, and a pivoting arm having at least one idler gear wherein the pivoting arm pivots between at least a first, non-damped position and a second, damped position in response to movement of a media support member. The damping gear includes a rotational resistance element, such as, without limitation, damping grease, a frictional mechanism, a regenerative braking mechanism, a magnetic braking mechanism, a centrifugal governor, and combinations thereof and/or of other suitable rotational resistance elements now or in the future known. The idler gear cooperates with one or more drive elements associated with the media support member, such as without limitation, a rack and pinion drive and/or a belt drive. The pivot arm is arranged such that, when a media support member is moved toward an open position, the drive element causes the pivot arm to move into the non-damped position wherein the idler gear on the pivot arm is disengaged from the damping gear, thus allowing free movement of the media support member. When the media support member moves toward the closed position, the pivot arm moves into the damped position wherein the idler gear on the pivot arm engages the damping gear, which in turn slows the motion of the drive element and media support member. In this manner, asymmetrical damping is achieved whereby the media support members open freely against only the spring force, but retract slowly with the dampening effect as the idler gear engages the dampening gear. 
     An asymmetrically-damped media centering mechanism is disclosed which includes a first media support member moveable along a longitudinal axis thereof and a second media support member moveable along a longitudinal axis thereof. The first and second media support members may share a common longitudinal axis of movement. The disclosed media centering mechanism includes a reciprocal movement mechanism operably coupled to the first and second media support members that is configured to translate a longitudinal movement of the first media support member into a corresponding opposite longitudinal movement of the second media support member. The media centering mechanism further includes a pivoting arm coupled to the reciprocal movement mechanism. The pivoting arm is pivotable between at least a first and a second position. During use, the pivoting arm pivots to the first position when the first and second media support members are moved closer to each other (e.g., when grasping or closing onto a media roll positioned therebetween), and the pivoting arm pivots to the second position when the first and second media support members are moved further apart from each other (e.g., when spreading the media support members to insert a media roll therebetween). A damping gear is provided that is configured to engage the reciprocal movement mechanism when the pivoting arm is in the first position. The reciprocal movement mechanism may include a first and second drive member operably coupled to the first and second media support members, respectively, and may include a drive belt operably coupled to the first and second drive members and at least partially disposed around the driven gear. Additionally or alternatively, the reciprocal movement mechanism may include a first and second rack member operably coupled to the first and second media support members, respectively, wherein a pinion gear is operably engageable with the first and second rack members and configured to translate movement of the first rack member into a corresponding opposite movement of the second rack member. In embodiments, the pinion gear is axially coupled to the driven gear. 
     Also disclosed is a method of centering a media roll, comprising the steps of providing a first and a second media support member moveable along a longitudinal axis and dimensioned to axially engage a media roll. The method includes the step of providing a reciprocal movement mechanism operably coupled to the first and second media support members wherein a longitudinal movement of one media support member causes a corresponding opposite longitudinal movement of the other media support member. A pivoting arm is provided, which operably couples to the reciprocal movement mechanism, wherein the pivoting arm pivots to the first position when the media support members are moved closer to each other, and the pivoting arm pivots to the second position when the media support members are moved further apart from each other. A damping gear is provided which is configured to engage the reciprocal movement mechanism when the pivoting arm is in the first position. 
     Also disclosed is a portable printer that includes a display having an overmolded bezel associated therewith. The overmolded bezel is formed from resilient material that provides shock resistance and which protects the display, printer, and associated components thereof from damage in the event the portable printer is dropped or otherwise mishandled. In embodiments, the overmolded bezel is formed from Versollan™ OM 1255NX-9, a thermoplastic elastomer manufactured by PolyOne Corporation of Avon Lake, Ohio, USA. The overmolded bezel additionally or alternatively seals the display and printer to resist the infiltration of contaminants, e.g., dust and moisture, into the display and/or printer. 
     Disclosed is a portable printer having ergonomic enhancements. In embodiments, a printer in accordance with the present disclosure includes a media loading arrangement capable of single-handed operation. A media cover may be unlatched using a lever operable by a single hand. Using a single hand, the media cover may be fully unlatched, e.g., both sides freed from an associated housing, such that the media cover swings clear of the housing to expose a media storage well. Media may be loaded into the media storage well and the media cover closed with one hand. Single-handed operation may provide a number of benefits. In one envisioned scenario, the portable printer may be hung from the waistbelt of a user, e.g., a warehouse worker. Such a worker is often situated precariously, such as on a forklift, on an elevated platform of a Hi-Lo machine, and the like, wherein using two hands to manipulate a portable device may be hazardous. By facilitating one-handed operation, a portable printer in accordance with the present disclosure may offer safer, more convenient, and more reliable operation. 
     In another aspect, a portable printer in accordance with the present disclosure includes a dual wall, frame housing that provides improved strength and shock resistance. The dual wall construction includes a continuous inner frame structure adapted to support one or more internal printer components, which may include, without limitation, a printhead, a roller assembly, a drive assembly, media centering assembly, and/or a battery assembly. The inner frame is surrounded at least in part by a second, outer structure that provides additional stiffness, strength, and drop resistance. The housing includes a media access opening and a corresponding media access cover configured to facilitate the loading of media into the printer. The size of the media access opening is kept to the minimum size necessary to accommodate the media for use with the printer. By minimizing the media opening, greater space is available for the inner frame and/or the outer structure, further improving the strength, rigidity, and impact resistance of the printer. 
     The disclosed printer may include one or more connectors that extend from the interior of housing to the exterior. While the connector(s) may include an electrical connector, other connector types are contemplated within the scope of the present disclosure, e.g., moisture-proof connectors, fluidic connectors, security connectors (e.g., K-Slot), and the like. In embodiments, two electrical connectors are provided, wherein a first connector is adapted to couple a source of electrical power to the printer and a second connector is adapted to couple a data signal to the printer. In embodiments, the disclosed printer may include a USB connector, a serial (e.g., RS-232, RS-422, RS-485), connector, a Firewire (IEEE-1394) connector, a network (10Base-T, 100Base-TX, and 1000Base-T) connector, and/or a parallel (IEEE 1284) connector. The disclosed printer may additionally or alternatively include a dust cover assembly that is adapted to cover one or more connectors. The dust cover assembly includes a cap portion that is dimensioned to seal the one or more connectors associated with the dust cover. In embodiments, the dust cover is formed from resilient material. The cover is joined to a base by a resilient hinge or tethering member that retains the cap portion to the base. The cap, hinge member, and base may be integrally formed. The hinge member may be a living hinge. The base is retained to the printer by any suitable manner of fastening, including without limitation, threaded fasteners, clips, tabs, and the like. Advantageously, the dust cover assembly may be user-replaceable, so that a worn or broken dust cover assembly may be readily replaced with a new dust cover assembly. In embodiments, a spare dust cover assembly may be stored within a recess provided by the printer housing. 
     A portable printer having a media feed cover assembly is disclosed. In certain applications, it may be desirable to feed media into the printer from an external media source. To facilitate external media feeding, the disclosed printer includes a media feed opening defined in the housing. A media feed cover is provided to seal the media feed opening from moisture, dust, and other contaminants. The media feed cover is supported by a pocket formed between the outer enclosure and the inner frame. The cover assembly is configured to provide two or more detents to enable the cover to be positioned in an open and a closed position. In an embodiment, the pocket includes a recess in the open and closed position that provides detents for each of the open and closed positions. 
     Also disclosed is a portable printer that includes an upper inner frame structurally associated with a lower inner frame to form an inner support structure. An asymmetrically-damped media centering assembly is fixed to the inner support structure. An upper housing and a lower housing are joined to the inner support structure to form a dual-wall housing assembly. A media opening defined in the upper housing exposing a media well, and a media access door having at least a closed position and an open position is operatively associated with the media opening. A latch assembly having a first, normally latched position and a second, unlatched position, the latch assembly is associated with the inner support structure and is configured to retain the media access door in the closed position when the latch is in the latched position, and to release the media access door when the latch is in the unlatched position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various embodiments of the subject instrument are described herein with reference to the drawings wherein: 
         FIG. 1  is a view of an embodiment of an asymmetrical damping mechanism in accordance with the present disclosure shown in a first, non-damped position; 
         FIG. 2  is a view of the  FIG. 1  embodiment of an asymmetrical damping mechanism in accordance with the present disclosure shown in a second, damped position; 
         FIG. 3  is a cross-sectional view of a pivot arm of the  FIG. 1  embodiment of an asymmetrical damping mechanism in accordance with the present disclosure; 
         FIG. 4  is a cross-sectional view of a damping gear of the  FIG. 1  embodiment of an asymmetrical damping mechanism in accordance with the present disclosure; 
         FIG. 5  is a perspective view of another embodiment of an asymmetrical damping mechanism in accordance with the present disclosure shown in a first, non-damped position; 
         FIG. 6  is a perspective view of the  FIG. 5  embodiment of an asymmetrical damping mechanism in accordance with the present disclosure shown in a second, damped position; 
         FIG. 7  is a perspective view of yet another embodiment of an asymmetrical damping mechanism in accordance with the present disclosure shown in a first, non-damped position; 
         FIG. 8  is a perspective view of the  FIG. 7  embodiment of an asymmetrical damping mechanism in accordance with the present disclosure shown in a second, damped position; 
         FIG. 9  is a view of still another embodiment of an asymmetrical damping mechanism in accordance with the present disclosure shown in a first, non-damped position; 
         FIG. 10  is a view of the  FIG. 9  embodiment of an asymmetrical damping mechanism in accordance with the present disclosure shown in a second, damped position; 
         FIG. 11  is a perspective view of an embodiment of a portable printer in accordance with the present disclosure; 
         FIG. 12  is another perspective view of the  FIG. 11  embodiment of a portable printer in accordance with the present disclosure; 
         FIG. 13  is an exploded view of the  FIG. 11  embodiment of a portable printer in accordance with the present disclosure; 
         FIG. 14  illustrates an inner frame of an embodiment of a portable printer in accordance with the present disclosure; and 
         FIG. 15  illustrates an embodiment of a dust cover assembly for a portable printer in accordance with the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Particular embodiments of the present disclosure are described hereinbelow with reference to the accompanying drawings; however, it is to be understood that the disclosed embodiments are merely exemplary of the disclosure, which may be embodied in various forms. Well-known and/or repetitive functions and constructions are not described in detail to avoid obscuring the present disclosure in unnecessary or redundant detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure. In addition, as used herein, terms referencing orientation, e.g., “top”, “bottom”, “up”, “down”, “left”, “right”, “clockwise”, “counterclockwise”, and the like, are used for illustrative purposes with reference to the figures and features shown therein. It is to be understood that embodiments in accordance with the present disclosure may be practiced in any orientation without limitation. In this description, as well as in the drawings, like-referenced numbers represent elements which may perform the same, similar, or equivalent functions. 
     With reference to  FIGS. 1-4 , an embodiment of an asymmetrically-damped media centering mechanism  100  is shown. The disclosed mechanism  100  is adapted for use with a toothed drive belt  118  that is operably coupled to a first media support drive member  119  and a second media support drive member  125 . While a toothed drive belt is shown, any suitable belt or chain may be used (e.g., vee belt, round belt, flat belt, drive chain, etc.). As shown, first drive member  119  engages drive belt  118  within a notched region  124 . Second drive member  125  engages belt  118  within notched region  126 . It should be noted that any suitable manner of attachment may be utilized such that linear motion of drive members  119 ,  125  is translated to/from drive belt  118 . The disclosed arrangement of drive belt  118 , first drive member  119 , and second drive member  125  provides for reciprocal linear movement of drive member  119  with respect to movement of drive member  125 . First drive member  119  and second drive member  125  may be slidably associated with one or more guides (not explicitly shown) that are configured to constrain the movement thereof to a substantially longitudinal axis of motion corresponding to the movement of belt  118 . 
     A pivot arm  110  that is rotatable around a pivot pin  115  is disposed on a support member  121 . Pivot arm  110  includes a first idler gear  113  and a driven gear  116  rotatably mounted thereupon adjacent to opposite ends  111  and  112 , respectively, of pivot arm  110 . First idler gear  113  and driven gear  116  are positioned on pivot arm  110  in essentially coplanar alignment with drive belt  118 . Drive belt  118  is disposed around idler gears  113  and  116  at one end of the mechanism  100 , and around a second idler gear  127  at an opposite end of mechanism  100 . As shown, drive belt  118  is continuous, however, drive belt  118  may be discontinuous or segmented. 
     A biasing member  128  is disposed between a free end  129  of drive member  119  and an anchor  130  and adapted to bias drive member  119  away from pivot arm  110 . Additionally or alternatively, a biasing member  128 ′ may be disposed between a free end  131  of drive member  125  and a corresponding anchor  130 ′. Biasing member  128  and/or biasing member  128 ′ may include an extension spring. At rest, biasing member  128  causes drive member  119  to be drawn leftward, and drive member  125  to be drawn rightward, e.g., causes both drive members  119 ,  125  to be drawn generally towards the center of centering mechanism  100 . A media support member (not explicitly shown) is associated with each of drive member  119 ,  125  to retain a media roll therebetween, as described herein. 
     The disclosed media centering mechanism includes a damping gear  120  that is configured to engage driven gear  116 . With particular reference to  FIG. 4 , damping gear  120  is associated with damping grease  122  that is applied between a movable surface  132  of damping gear  120  and a stationary surface, e.g., support member  121  and/or pin  123 . It is envisioned that any suitable damping grease, such as without limitation, SmartGrease™ Fluorocarbon Gel, manufactured by Nye Lubricants, Inc. of Fairhaven, Mass., United States, may be utilized. Damping grease  122  resists the rotational motion of damping gear  120 . 
     Referring again to  FIG. 1 , during use, first drive member  119  and/or second drive member  125  may be caused to be moved in a direction indicated by the arrows, e.g., generally outwardly from the center of mechanism  100 , overcoming the biasing force of biasing member  128 , and causing belt  118  to traverse in a generally counterclockwise direction. The counterclockwise motion of belt  118  is translated through first idler gear  113  and/or driven gear  116  to cause a corresponding counterclockwise rotation of pivot arm  110 , which, in turn, causes driven gear  116  to disengage from damping gear  120 . In this manner, the outward linear motion of first drive member  119  and second drive member  125  is unimpeded by damping gear  120  thus enabling a user to freely open the media support members (not explicitly shown) associated therewith to facilitate the introduction of a media roll therebetween. 
     Continuing now with reference to  FIG. 2 , the first drive member  119  and/or second drive member  125  may be caused to be moved in the opposite direction (generally inwardly towards the center of mechanism  100 ) by, e.g., the biasing force of biasing member  128 . The described inward motion of first drive member  119  and second drive member  125 , in turn, causes belt  118  to traverse in a generally clockwise direction. The clockwise motion of belt  118  is translated through first idler gear  113  and/or driven gear  116  to cause a corresponding clockwise rotation of pivot arm  110 , which, in turn, engages driven gear  116  with damping gear  120 . The rotational resistance of damping gear  120  is translated through driven gear  116  to belt  118 , which slows the movement of first drive member  119  and second drive member  125 , and the media support members associated therewith. Thus, the dampening effect of engaged dampening gear  120  enables the return, or closing, of the first drive member  119  and second drive member  125 , and the media support members associated therewith, to be achieved in a smooth and controlled manner. 
     Other embodiments are contemplated wherein a second damping gear (not explicitly shown) may be employed to provide damping in a direction opposite to that provided by a first damping gear. In one arrangement, the second damping gear is arranged such that the pivot arm causes the second damping gear to engage one or more of the idler or driven gears mounted thereupon when the drive member(s) move in an opening direction. 
     Turning now to  FIGS. 5 and 6 , an embodiment of a print media subassembly  200  having an asymmetrically damped media centering mechanism  201  is shown. Print media subassembly includes a housing  205  having defined therein a media storage well  250  that is dimensioned to accommodate a variety of roll-fed media. Housing  205  includes a support member  221  configured to support media centering mechanism  201  as described herein. Housing  205  includes one or more mounting bosses  251  configured to accept a fastener, pin, or other structural or connective element. The disclosed mechanism  201  includes a drive belt  218  that is operably coupled to a first media support drive member  219  and a second media support drive member  225 . While a toothed drive belt  218  is shown, any suitable belt or chain may be used as described herein. As shown, first drive member  219  engages drive belt  218  within a notched region  224 . Second drive member  225  engages belt  218  within notched region  226 . First and second drive members  219 ,  225  include a retention tab  249  that is configured to retain belt  218  within notched region  224  and notched region  226 , respectively. It should be noted that any suitable manner of retention may be utilized such that linear motion of drive members  219 ,  225  is translated to/from drive belt  218 . 
     Drive belt  218 , first drive member  219 , and second drive member  225  provide for reciprocal linear movement of drive member  219  with respect to movement of drive member  225 . First drive member  219  is slidably disposed within a slot  242  that is defined in support member  221  and includes a wide portion  244  and a narrow portion  243 . Second drive member  225  is slidably disposed within a slot  245  that is defined in support member  221  and includes a wide portion  247  and a narrow portion  246 . Slots  242  and  245  are configured to constrain the movement of drive members  219 ,  225 , respectively, to a substantially longitudinal axis of motion corresponding generally to the movement of belt  218 . A positive stop  248  is disposed at an end of slot narrow portion  243  and/or slot narrow portion  246  and configured to limit the longitudinal travel of drive member  219  and/or drive member  225 , respectively. 
     A pivot arm  210  that is rotatable around a pivot pin  215  is disposed on a support member  221 . Pivot arm  210  includes a first idler roller  213  and a driven gear  216  rotatably mounted on pivot arm  210 . First idler roller  213  and driven gear  216  are positioned on pivot arm  210  in essentially coplanar alignment with drive belt  218 . Drive belt  218  is disposed around first idler roller  213  and driven gear  216  at one end of the mechanism  201 , and around a second idler roller  227  at an opposite end of mechanism  201 . As shown, drive belt  218  is continuous, however, drive belt  218  may be discontinuous or segmented. 
     An extension spring  228  is disposed between an anchor pin  230  provided on support member  221 , and a mounting tab  229  provided on drive member  219 . As can be readily appreciated, extension spring  228  is configured to bias drive member  219  away from pivot arm  210 , which, by operation of drive belt  218 , first idler roller  213 , driven gear  216 , and second idler roller  227 , serves to bias drive member  225  toward pivot arm  210  in a reciprocally synchronized manner. Biasing member  228  causes drive member  219  to be drawn leftward, and drive member  225  to be drawn rightward, e.g., causes both drive members  219 ,  225  and media support members  240 ,  241  respectively associated therewith to be drawn generally towards the center of storage well  250  to retain a roll of media therebetween. 
     First media support member  240  is operatively associated with drive member  219 , and second media support member  241  is operatively associated with drive member  225 . As shown, media support members  240 ,  241  are joined to drive members  219 ,  225 , respectively, by a fastener  252  which may include a threaded fastener, rivet, pin, or clip, however, any suitable manner or combination of attachment may be utilized, including without limitation, chemical bonding, adhesive, welding, and the like. Media support member  240 ,  241  may be integrally formed with drive member  219 ,  225 , respectively. 
     The disclosed media centering mechanism includes a damping gear  220  that is configured to engage with driven gear  216 . Damping gear  220  is associated with damping grease (not explicitly shown) that is applied between a movable surface of damping gear  220  and a stationary surface, e.g., support member  221  and/or pin  223  and adapted to resist the rotational motion of damping gear  220 . Any suitable damping grease (as previously described herein) may be utilized. 
     During use, a user loads a roll of media by opening one or both media support members  240 ,  241 , inserting a roll of media (not explicitly shown) and releasing the media support members  240 ,  241  which retain the media roll under tension provided by extension spring  228 . In greater detail, a user moves first media support member  240  and/or second media support member  241  generally outwardly from the center of mechanism  201 , thereby overcoming the biasing force of extension spring  228 , and causing belt  218  to traverse in a generally counterclockwise direction. The counterclockwise motion of belt  218  is translated through idler roller  213  and/or driven gear  216  to cause a corresponding counterclockwise rotation of pivot arm  210 , which, in turn, causes driven gear  216  to disengage from damping gear  220 . In this manner, the outward linear motion of first drive member  219  and second drive member  225  is unimpeded by damping gear  220  thus enabling a user to freely open media support members  240 ,  241  associated therewith to facilitate the introduction of a media roll therebetween. 
     Continuing, a user may relax pressure on, or release completely, media support members  240 ,  241  to allow first drive member  219  and/or second drive member  225  to move in the opposite direction, e.g., closing direction generally inwardly towards the center of mechanism  201  by e.g., the biasing force of extension spring  228 . The described inward motion of first drive member  219  and second drive member  225 , in turn, causes belt  218  to traverse in a generally clockwise direction. The clockwise motion of belt  218  is translated through first idler roller  213  and/or driven gear  216  to cause a corresponding clockwise rotation of pivot arm  210 , which, in turn, engages driven gear  216  with damping gear  220 . The rotational resistance of damping gear  220  is translated through driven gear  216  to belt  218 , which slows the movement of first drive member  219 , second drive member  225 , and the associated media support members  240 ,  241 . Thus, the dampening effect of engaged dampening gear  220  enables the return, or closing, of media support members  240 ,  241  to be achieved in a smooth and controlled manner. 
     With reference now to  FIGS. 7 and 8 , an embodiment of an asymmetrically-damped media centering mechanism  300  employing a rack and pinion arrangement is shown. The disclosed media centering mechanism  300  includes a first media support member  340  and a second media support member  341 . The first and second media support members  340 ,  341  are joined respectively to rack members  342 ,  343  that extend inwardly towards the center of mechanism  300 . The media support members  340 ,  341  may be joined to the respective rack member  342 ,  343  by any suitable manner of attachment, including threaded fasteners, adhesive, welding, clips. Additionally or alternatively, media support members  340 ,  341  may be integrally formed with the respective rack member  342 ,  343  thereof. 
     Rack members  342 ,  343  are reciprocally synchronized by pinion gear  314  that is axially coupled to driven gear  313 , such that pinion gear  314  and driven gear  313  rotate in tandem. Pinion gear  314  and driven gear  313  may be positively joined by a common shaft (not explicitly shown) and/or may be integrally formed. Media support members  340 ,  341  are biased toward each other by an extension spring  328  that is fixed to media support members  340 ,  341  by a retention clip  330 . The biasing force of extension spring  328  is sufficient to secure a media roll (not explicitly shown) between media support members  340 ,  341 . Media support members  340 ,  341  may include media hubs  344 ,  345 , respectively, that are dimensioned to operatively engage an inner diameter (e.g., a core) of a media roll. 
     A damping gear  320  rotatably mounted on pin  323  is associated with damping grease  322  that is applied between a movable surface of damping gear  320  and an adjacent stationary surface (not explicitly shown) and/or pin  323 . Damping gear  320  is adapted to resist the rotational motion thereof by the viscous friction provided by damping grease  322 . As described elsewhere herein, any suitable damping grease may be utilized. In embodiments, additional or alternative friction-inducing elements may be employed in association with damping gear  320 , including without limitation magnetic elements, inertial elements (e.g., a flywheel), clockworks elements, clutch mechanisms, and the like. 
     Pinion gear  313  engages movable gear  316  that is rotatably mounted on a pivot arm  310  that is configured to pivot on an axis (not explicitly shown) such that, when media support members  340 ,  341  are moved apart from each other (e.g., when loading a media roll), pivot arm  310  swings movable gear  316  away from damping gear  320 , thereby disengaging movable gear  316  and damping gear  320 . Conversely, when media support members  340 ,  341  are moved toward from each other (e.g., when a media roll is grasped therebetween for use), pivot arm  310  swings movable gear  316  towards damping gear  320 , thereby engaging movable gear  316  and damping gear  320 . In an embodiment, the pivot axis of pivot arm  310  is coincident with the rotational axis of driven gear  313  and/or pinion gear  314 . The pivoting motion of pivot arm  310  may be induced by parasitic friction that may be present among and between driven gear  313 , pinion gear  314 , and/or pivot arm  310 , and associated components thereof. Thus, the dampening effect of engaged dampening gear  320  enables the return, or closing, of media support members  340 ,  341  to be achieved in a smooth and controlled manner while permitting the opening of media support members  340 ,  341  to be performed without any appreciable resistance apart from that provided by extension spring  328 . 
     Turning to  FIGS. 9 and 10 , still another embodiment of an asymmetrical damping mechanism  400  in accordance with the present disclosure is shown wherein a damping roller  420  is disposed outside of a perimeter defined by drive belt  418 . Drive belt  418  is of a toothed type having a plurality of drive teeth  421  disposed on at least an outer surface  419  thereof. A pivoting arm assembly  410  is configured such that as the drive belt moves in a clockwise direction, e.g., a direction corresponding to the closing of a pair of media support members (not explicitly shown), the pivoting arm  410  rotates in a clockwise direction, causing the outer teeth  421  of drive belt  418  to engage damping roller  420 . 
     Turning to  FIGS. 11 and 12 , an embodiment of a portable printer  500  in accordance with the present disclosure includes a control panel  523  having an overmolded bezel  520  associated therewith. The overmolded bezel  520  is formed from resilient material that may provide shock resistance and prevent the infiltration of contaminants into the control panel  523 , printer  500 , user interface element(s)  524 , and components associated therewith. The control panel  523  includes a display  522  that is adapted to present operational information to a user. By way of example, and without limitation, the display  522  may present status information, diagnostic information, setup information, and the like. Display  522  may include a text display, a graphical display, a monochrome display, a color display, and may include any display means now or in the future known, including without limitation a liquid crystal display (LCD), a light emitting diode (LED) display, an organic light emitting diode (OLED) display, a vacuum fluorescent display, and the like. Control panel  523  includes one or more user interface elements  524 , e.g., buttons and/or switches, adapted to accept user inputs. The overmolded bezel  520  may include the one or more user interface elements  524 , such that the resilient material of the bezel  520  provides a seal associated with the one or more user interface elements  524 . 
     Printer  500  includes a housing  540  having an upper housing  542  and a lower housing  544 . A media access door  510  is provided to facilitate the loading and unloading of media (not explicitly shown) in a media well  550 . As shown in  FIG. 13 , media centering assembly  560  is positioned within media well  500 . Media centering assembly includes a pair of media support members  561  and an asymmetrically-damped centering mechanism  562  as described hereinabove. Printer  500  includes a belt clip  526  affixed to the lower housing  544  thereof. Belt clip  526  may be removably coupled to lower housing  544  by any suitable manner of attachment, such as without limitation threaded fasteners, one or more clips, and the like. 
     Printer  500  includes an upper inner frame  548 , as shown in  FIG. 14 , and a lower inner frame  546 . The combination of upper inner frame  548  and lower inner frame  546  provides an inner support structure, which, in combination with upper housing  542  and lower housing  544 , forms a dual-wall housing assembly that provides increased impact resistance and rigidity. Latch lever  530  is operably associated with media cover  510  such that actuation of latch lever  530  disengages one or more latches (not explicitly shown) to permit media cover  510  to open. Media cover  510  is configured to be positioned in at least a first, closed position as shown in  FIG. 11  and a second, open position as shown in  FIG. 12 . Detents are provided in association with media cover  510  to retain media cover  510  in each of the open and closed positions. A spring (not explicitly shown) may be associated with media cover  510  and configured to bias media cover  510  toward an open position as shown in  FIG. 12 . Upper inner frame  548  provides support for latch lever  530 . An opening  532  is defined in housing  540  to facilitate access to and actuation of latch lever  530 . A fingertip recess  531  is defined in latch lever  530  to enable the convenient actuation thereof by, e.g., the fingertip of a user. In this manner, media cover  510  may be unlatched using a single-handed motion to expose media storage well  550  for loading and loading media. A media roller  536  is operably associated with upper inner frame  548  to facilitate feeding of media along a print path. 
     Lower inner frame  546  includes a battery well  561  that is adapted to operably receive a battery pack  560 . Battery pack  560  may include one or more cells, which may be connected in series, in parallel, or in a combination of series and parallel, to provide operating power to printer  500 . Battery pack  560  may include a primary battery (e.g., non-rechargeable), a secondary battery (e.g., rechargeable), and or combinations thereof. Battery pack  560  may include an identifier, e.g., a physical, an electrical, or an optical identifier, that identifies to the printer  500  one or more characteristics of the battery pack  560 . Such characteristics may include, without limitation, a voltage, an amperage, an ampere-hour rating, a battery type (e.g., NiCd, NiMH, Li-ion), and a charge cycle count. 
     As shown in  FIG. 15 , printer  500  includes dust cover assembly  570  that is dimensioned to cover one or more connectors (not explicitly shown). The dust cover assembly  570  may be formed from resilient material, e.g., silicone, neoprene, or other elastomeric material. The dust cover assembly includes a cap  571  that is joined to a base  574  by a resilient hinge or tethering member  575  that retains the cap  571  to the base  574 . The cap  571 , hinge member  575 , and base  574  may be integrally formed. Hinge member  575  may be a living hinge. The base  575  is retained to lower housing  544  by any suitable manner of fastening, including without limitation, threaded fasteners  572 , clips, tabs, and the like. Advantageously, the dust cover assembly may be user-replaceable, so that a worn or broken dust cover assembly  570  may be readily replaced with a new dust cover assembly  570 . In embodiments, a spare dust cover assembly  570  may be stored within a recess provided by the printer housing (not explicitly shown.) 
     The described embodiments of the present disclosure are intended to be illustrative rather than restrictive, and are not intended to represent every embodiment of the present disclosure. Further variations of the above-disclosed embodiments and other features and functions, or alternatives thereof, may be made or desirably combined into many other different systems or applications without departing from the spirit or scope of the disclosure as set forth in the following claims both literally and in equivalents recognized in law.