Abstract:
A cartridge identification system for identifying a characteristic of a cartridge inserted in a printer. The cartridge identification system comprises an identification circuit which is triggered by an electrical connection between a printed circuit board coupled to the cartridge and a plurality of spring contacts in a cartridge receptacle in the printer. An electrical logic signal is read by an internal processing unit, which determines a characteristic of the cartridge based on the logic signal.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS  
         [0001]    Not Applicable  
         STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH  
         [0002]    Not Applicable  
         TECHNICAL FIELD  
         [0003]    The present invention relates to a cartridge-based printer and associated cartridge, and more particularly to a method and apparatus for identifying a cartridge inserted in a cartridge-based printer.  
         DESCRIPTION OF THE BACKGROUND ART  
         [0004]    There are a number of U.S. patents that disclose electronic apparatus for printing indicia on labels, some of these are restricted to hand held units and others that disclose tabletop units. Hand held labeling machines are disclosed, for example, in U.S. Pat. No. 4,264,396, Stewart; U.S. Pat. No. 4,407,692, Torbeck; U.S. Pat. No. 4,473,426, Goodwin et al.; U.S. Pat. No. 4,477,305, Hamisch; U.S. Pat. No. 4,490,206, Makely; U.S. Pat. No. 4,497,683, Hamisch; U.S. Pat. No. 4,498,947, Hamisch et al.; U.S. Pat. No. 4,511,422, Hamisch et al.; U.S. Pat. No. 4,544,434, Mistyurik; U.S. Pat. No. 4,556,442, Torbeck; U.S. Pat. No. 4,561,048, Hamisch et al.; and U.S. Pat. No. 4,680,078, Vanderpool et al. Tabletop units for this general purpose, some of which are portable are described in U.S. Pat. No. 4,440,248, Teraoka; U.S. Pat. No. 4,501,224, Shibayama; U.S. Pat. No. 4,630,538, Cushing; and U.S. Pat. No. 4,655,129, Wirth et al.  
           [0005]    The electronic machines for printing labels of the type disclosed above all include the same general combination of elements, a print head, means for feeding labeling media to be printed past the print head, a microprocessor, a read only memory programmed with appropriate instructions to operate the microprocessor, a random access memory, a keyboard with letter, number, and function keys for the entry of alphanumeric information and instructions concerning the indicia to be printed, and a visual display such as a LED, LCD unit to assist the operator in using the machine. In a hand held printer, these components may all be enclosed in a single housing.  
           [0006]    The labeling media comprises labeling material attached to a carrier strip, and is fed through the printer. Legends, or other indicia, are printed on the labels by the printer. The printed labels are then removed from the carrier strip and attached to the objects needing identification. As there are many types of label applications, there are many combinations of labels and carrier strips that provide labels of varying sizes, colors and formats.  
           [0007]    A particular type of print head employs thermal transfer printing technology. Thermal transfer printing uses a heat generating print head to transfer a pigment, such as wax, carbon black, or the like, from a thermal transfer ribbon to a labeling media. By using digital technology, characters are formed by energizing a sequence of pixels on the print head which in turn melt the wax or other pigment on the ribbon transferring the image to the labeling media.  
           [0008]    Many prior art thermal printers include various means and methods for automatically identifying a width or identifying a characteristic feature of a labeling media or tape associated with a cartridge inserted in a cartridge-based printer. For example, U.S. Pat. No. 5,492,420, Nunokawa, discloses a plurality of holes formed on the bottom of a cartridge wall wherein the depths of the holes are varied to selectively trip a plurality of switches in the cartridge holder, thereby providing an indication of the type of cartridge that has been inserted. Similarly, U.S. Pat. No. 5,553,818 discloses a portable printer in which a plurality of plunger assemblies in the printer mechanism are selectively activated depending on the configuration of a plurality of punch-out tabs in the cartridge to provide an indication of the type of cartridge inserted in a printer. Another similar system, U.S. Pat. No. 5,562,353 discloses a tape printing apparatus in which microswitches in the printer are selectively tripped by projections on the cartridge to provide identification information.  
           [0009]    While a number of identification circuits for identifying a cartridge inserted in a cartridge-based label printer are therefore known in the art, these systems typically require complicated switching systems which require a number of moving parts, and are therefore relatively expensive to implement. Furthermore, due to the number of moving parts, repetitive insertion and removal of a cartridge from the printer can cause significant wear on the switching systems, which can lead to incorrect identifications, maintenance problems and even failure of the printer. A need exists, therefore, for a cartridge identification system for use in a hand held cartridge-based label printer which is inexpensive to construct, reliable, and easy to maintain.  
         SUMMARY OF THE INVENTION  
         [0010]    The present invention provides a method and apparatus for identifying a cartridge inserted in a cartridge-based printer. Generally, a first plurality of electrical contacts are provided on the printer cartridge. As the printer cartridge is inserted into the printer, a second plurality of electrical contacts in the printer mate with the first plurality of contacts, providing an identification of the cartridge to internal printer circuitry. The identification provides information relating to characteristics of the inserted cartridge, and more particularly identifies a width of a labeling media contained in the cartridge  
           [0011]    More specifically, the cartridge-based printer includes a plurality of spring contacts which extend axially into a cartridge receptacle. The spring contacts are each electrically coupled to a printed circuit board in the thermal printer device, where they are selectively connected to a circuit common and/or a reference potential. The cartridge includes a printed circuit board or other conductive media supplying a second plurality of electrical contacts. When the cartridge is inserted in the cartridge receptacle, the electrical contacts coupled to the wall of the cartridge selectively connect one or more of the spring contacts in the cartridge receptacle to another of the spring contacts in the cartridge receptacle, providing an electrical identification signal identifying the cartridge, and more particularly a width of the labeling media in the cartridge.  
           [0012]    The spring contacts are designed to elastically deform and to provide a spring force opposing the cartridge when the cartridge is inserted into the cartridge receptacle, and to expand when the cartridge is removed. The force provided by the elasticity of the spring contact therefore provides and maintains a strong electrical connection between the conductive material coupled to the cartridge and the printed circuit board in the printer. Furthermore, due to the ability to expand and contract, the spring contacts can provide an accurate identification of the inserted cartridge, even when there are minor variations in the size of the cartridge or in the alignment of the cartridge in the cartridge receptacle.  
           [0013]    The second plurality of electrical contacts are preferably constructed as a printed circuit board. The printed circuit board can be constructed of typical circuit board materials, or can comprise a flexible printed circuit board, a metallized tape, or other conductive material. The printed circuit board is preferably adhesively coupled to the wall of the cartridge, thereby providing an inexpensive means for identifying the cartridge.  
           [0014]    A general objective of the present invention is to provide a method and apparatus for automatically identifying a characteristic of a cartridge inserted in a cartridge-based printer which is inexpensive to implement. This objective is accomplished by providing an identification circuit which comprises an electrical connection between inexpensive electrical spring contacts and a printed circuit board.  
           [0015]    Another object of the invention is to provide a method and apparatus for automatically identifying a characteristic of a cartridge inserted in a cartridge-based printer which has high durability. This objective is achieved by providing an electrical identification circuit with a minimal number of moving parts.  
           [0016]    The foregoing and other objectives and advantages of the invention will appear from the following description. In the description, reference is made to the accompanying drawings which form a part hereof, and in which there is shown by way of illustration a preferred embodiment of the invention. Such embodiment does not necessarily represent the full scope of the invention, however, and reference is made therefore to the claims herein for interpreting the scope of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]    [0017]FIG. 1 is a perspective view of a hand held label printer which employs the present invention;  
         [0018]    [0018]FIG. 2 is a top view of the printer of FIG. 1 with the cartridge removed;  
         [0019]    [0019]FIG. 3 is an exploded perspective view of the printer of FIG. 2;  
         [0020]    [0020]FIG. 4 is a top perspective view of the cartridge of FIG. 1;  
         [0021]    [0021]FIG. 5 is a bottom perspective view of the cartridge of FIG. 1;  
         [0022]    [0022]FIG. 6 is a bottom view of the cartridge of FIG. 1;  
         [0023]    [0023]FIG. 7 is a top perspective view of the cartridge receptacle of the printer of FIG. 2;  
         [0024]    [0024]FIG. 8 is a bottom perspective view of the cartridge receptacle of FIG. 7;  
         [0025]    [0025]FIG. 9 is a perspective view of the camshaft, cam and lever of FIG. 3;  
         [0026]    [0026]FIG. 10 is an exploded perspective view of the cartridge receptacle and cutter mechanism of FIG. 3;  
         [0027]    [0027]FIG. 11 is a detailed top view of the printer mechanism assembly of FIG. 3 with the platen roller in the nonprinting position;  
         [0028]    [0028]FIG. 12 is a detailed top view of the printer mechanism assembly of FIG. 4 with the platen roller in the printing position;  
         [0029]    [0029]FIG. 13 is a front view of the printer of FIG. 1 with the lever in the lock position;  
         [0030]    [0030]FIG. 14 is a partial illustration of the cartridge receptacle of FIG. 7 after assembly;  
         [0031]    [0031]FIG. 15 is a side illustration view of a spring contact of FIG. 3 as assembled in the printed circuit board of FIG. 3;  
         [0032]    [0032]FIG. 16 is a partial circuit diagram of the printed circuit board of FIG. 3, illustrating the cartridge identification circuit constructed in accordance with the present invention;  
         [0033]    [0033]FIG. 17 is a partial circuit diagram illustrating the connection of the spring contact;  
         [0034]    [0034]FIG. 18 is a first embodiment of the printer circuit board of FIG. 5;  
         [0035]    [0035]FIG. 19 is a second embodiment of the printed circuit board of FIG. 5; and  
         [0036]    [0036]FIG. 20 is a third embodiment of the printed circuit board of FIG. 5. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0037]    Referring particularly to FIGS.  1 - 3 , a thermal printing machine  10  which employs the preferred embodiment of the present invention includes a molded plastic housing  2  that supports a keyboard  4  on its front surface and a display  6  positioned above the keyboard  4 . An opening  8  formed in the housing  2  above the display  6  receives a cartridge  12  containing labeling media  14  and an ink ribbon  16  (shown in FIG. 6). The cartridge  12  is inserted through the opening  8  into a cartridge receptacle  18  housed in the printer housing  2 , and the labeling media  14  and ink ribbon  16  from the cartridge are threaded through a printer mechanism assembly  20  including a print head  22  and roller platen  24  for printing indicia on labels forming part of the labeling media  14 . The printed labels pass through a cutter mechanism  26  which cuts the labeling media to separate the printed labels from unprinted labels.  
         [0038]    The labeling media  14  is known in the art, and generally comprises a carrier web which supports a series of adhesive labels. The size, width, color, and type of web material varies depending upon the particular print application. The labeling media is dispensed from the cartridge  12 , and urged along a web path as it is consumed by the printer  10 .  
         [0039]    Referring to FIGS.  3 - 7 , the cartridge  12  includes a cartridge housing  28  having a top wall  30  and a bottom wall  32  joined by periphery walls  34 ,  36 ,  38 ,  40 . The periphery walls  34 ,  36 ,  38 ,  40  define a semi circular labeling media container  42  and a rectangular ink ribbon container  44  joined to the labeling media container  42 . The top wall  30  extends past the periphery walls  34 ,  38 , and defines a printing area  46  outside of the housing periphery walls  34 ,  38  at the junction of the labeling media container  42  and ink ribbon container  44 . Labeling media  14  and ink ribbon  16  from inside the cartridge housing  28  pass through the printing area  46  for engagement with the roller platen  24  and print head  22 . A shelf  48  formed along one edge of the top wall  30  is flush with the printer opening  8  to allow engagement of the shelf  48  with a lever  50  which locks the cartridge  12  in the receptacle  18 .  
         [0040]    The labeling media container  42  receives the labeling media  14  in the form of a roll. An exit slot  52  formed in the periphery wall  34  defining the labeling media container  42  opens into the printing area  46 , and provides an exit for the labeling media  14  and ink ribbon  16  to pass out of the cartridge housing  28  and into the printing area  46 . A projection  54  extending adjacent to the exit slot  52  guides the labeling media  14  and ink ribbon  16  as they exit the cartridge  12  through the exit slot  52 .  
         [0041]    The ink ribbon container  44  extends tangentially from the semicircular labeling media container  42 , and has a proximal end  56  which opens into the labeling media container  42  and an opposing, closed, distal end  58  joined by the exterior periphery wall  36  which is a tangential extension of the labeling media container periphery wall  34 . The interior ink ribbon periphery wall  38  extending between the proximal and distal ends  56 ,  58  is spaced from the ink ribbon exterior periphery wall  36 , and defines a boundary of the printing area  46 . Ink ribbon  16  which has passed through the printing area  46  reenters the ink ribbon container  44  through an entrance slot  60  formed at the junction of the interior ink ribbon periphery wall  38  and the ink ribbon container periphery end wall  40 .  
         [0042]    An ink ribbon supply spool (not shown) is supported between the top and bottom walls  30 ,  32  of the cartridge housing  28 , and has a roll of ink ribbon  16  wound thereon. The ink ribbon  16  is unwound from the supply spool, and passes out of the cartridge  12  with the labeling media  14  through the exit slot  52 . The ink ribbon  16  reenters the cartridge  12  through the entrance slot  60 , and is wound onto an ink ribbon take up spool (not shown).  
         [0043]    The take up spool is supported between the cartridge housing top and bottom walls  30 ,  32 , and is rotatably driven by an ink ribbon drive shaft  62  which extends through an opening  64  formed in the cartridge bottom wall  32 . The shaft  62  engages the take up spool to rotatably drive the spool and wind the ink ribbon  16  thereon.  
         [0044]    A labeling media guide  66  is formed at the ink ribbon container distal end  58 , and extends perpendicular to the interior ink ribbon periphery wall  38 . A guiding slot  67  formed in the guide  66  directs the labeling media  14  which has passed through the printing area  46  toward the cutter mechanism  26 .  
         [0045]    A conductive strip  302  is coupled to the periphery wall  34 . The conductive strip  302  is positioned on the wall  34  in a location selected to provide an electrical connection between the conductive strip  302  and spring contacts  300  (FIG. 3) for identifying the cartridge  12  as will be described below. The wall  34  can include a flat mounting section  303  to which the conductive strip  302  can be mounted by adhesive, or in other ways apparent to those of skill in the art. The conductive strip  302  is preferably adhesively coupled to the wall  34  of the cartridge  12 , and can be constructed of typical circuit board materials, flexible printed circuit board materials, a metallized tape, or other conductive material.  
         [0046]    Referring back to FIGS.  1 - 3 , the cartridge  12  is received in the cartridge receptacle  18  housed in the printer housing  2 . The printer housing  2  is, preferably, formed from two halves  68 ,  70 , and houses printer components, such as the cartridge receptacle  18 , the keyboard  4 , display  6 , the cutter mechanism  26 , a printed circuit board  72  having printer circuitry, an identification circuit for identifying a cartridge  12  inserted into the cartridge receptacle  18 , and the like. The printed circuit board  72  further includes a plurality of spring contacts  300  which extend from one end of the board  72  into the cartridge receptacle  18  of the assembled printer  10  for electrically connecting to the conductive strip  302  coupled to the cartridge  12 , as described below.  
         [0047]    The opening  8  formed in the housing top half  68  provides access to the cartridge receptacle  18  for insertion of the cartridge  12  into the receptacle  18 . A slot  74  formed in the housing  2  adjacent the cutter mechanism  26  provides an exit for labeling media  14  (FIG. 6) which has passed through the cutter mechanism  26 .  
         [0048]    Referring to FIGS.  6 - 12 , the cartridge receptacle  18  has a sidewall  76  generally shaped to conform with the cartridge periphery walls  34 ,  36 ,  38 ,  40 , and a floor  78  which supports the cartridge  12  therein. The sidewall  76 , therefore, includes at least a portion which is semi-circular or arcuate in shape to receive the semi-circular labeling media container  42 . A plurality of slots  304  are defined in the sidewall  76 , the slots  304  being sized and dimensioned to receive the spring contacts  300  (FIG. 3) extending axially from the printed circuit board  72  (FIG. 3).  
         [0049]    An eject mechanism  80  is formed as an integral part of the receptacle floor  78 , and includes a cantilevered arm  82  with a button  84  extending perpendicular to the arm  82  from the arm distal end  86 . The button  84  extends away from the receptacle floor  78  through the printer housing  2  (FIG. 2) for engagement by a user. The user urges the button  84  toward the receptacle  18  to engage the arm  82  with the cartridge  12  and push the cartridge  12  out of the receptacle  18 .  
         [0050]    The printer mechanism assembly  20  is fixed to the printer receptacle  18 , and includes the stationary print head  22  and pivotable platen roller  24  mounted on a U-shaped frame  88 . The U-shaped frame  88  includes two upwardly extending legs  90 ,  92  joined by a base  94  (FIG. 2). One leg  90  has an inwardly facing surface  96  for mounting the print head  22  thereon. The opposing leg  92  has a distal end  98  with a tab  100  extending inwardly toward the one leg  90 . Preferably, the frame  88  is fixed to the receptacle  18  with screws  91 . However, any method known in the art for fixing a frame to another object, such as rivets, bonding, and the like, can be used without departing from the scope of the present invention.  
         [0051]    The fixed thermal print head  22  is mounted to the inwardly facing surface  96  of the leg, and extends into the cartridge printing area  46  when the cartridge  12  is received in the receptacle  18 . The print head  22  cooperates with the ink ribbon  16  and the labeling media  14  such that the print head  22  can print characters or symbols on the labeling media. This is described in greater detail in U.S. Pat. No. 5,078,523 which is incorporated herein by reference. The labeling media  14  and ink ribbon  16  passing through the printing area  46  are advanced past the print head  22  by the platen roller  24  which maintains the ribbon  16  and labeling media  14  in close cooperation with the print head  22 .  
         [0052]    The platen roller  24  is mounted on a roller shaft  102  which is rotatably fixed to an end  108  of a pivot linkage  104 . One end of the drive shaft extends through the receptacle floor  78 . A drive gear  106  is fixed to the one end of the shaft  102 , and is coaxial with the platen roller  24 . The drive gear  106  engages a stationary gear  114  which is rotatably mounted to the underside of the receptacle floor  78 . The stationary gear  114  forms part of a gear assembly  116 , and meshes with the drive gear  106  to rotatably drive the platen roller  24 .  
         [0053]    The pivot linkage  104  has an opposing end  110  pivotally fixed to a pin  112  supported between the frame tab  100  and base  94  (FIG. 2). The pivot linkage pivots  104  about the pin  112  to move the platen roller  24  between a printing position (shown in FIG. 12) and a nonprinting position (shown in FIG. 11) and to engage and disengage the drive gear  106  from the stationary gear  114 . A cam follower  111  extending from the pivot linkage  104  between the linkage ends  108 ,  110  engages a cam  118  to pivot the linkage  104  about the pin  112 . Although fixing the pivot linkage  104  to the pin  112  supported between the frame tab  100  and base  94  (FIG. 2) is disclosed, other methods for movably mounting the platen roller relative to the print head, such as slidably mounting the roller shaft in a slot formed in the housing and the like, can be used without departing from the scope of the present invention.  
         [0054]    As shown in FIG. 12, when the pivot linkage  104  pivots to move the platen roller  24  to the printing position, the drive gear  106  engages a rotatably driven stationary gear  114  to rotatably drive the platen roller  24 , and the platen roller  24  extends into the receptacle  18  (FIG. 7) and urges the labeling media  14  and ink ribbon  16  against the print head  22 . In the nonprinting position shown in FIG. 11, the drive gear  106  is disengaged from the stationary gear  114 , and the platen roller  24  is spaced from the print head  22  to allow insertion of the labeling media  14  and ink ribbon  16  therebetween.  
         [0055]    Referring to FIGS.  2 - 4 ,  8 - 13 , the cam  118  engages the pivot linkage  104  to move the platen roller from the nonprinting position to the printing position and to engage and disengage the drive gear  106  with the stationary gear  114 . A spring  121  wrapped around one end of the pin  112  biases the linkage  104  against the cam  118  to bias the pivot linkage  104  away from the platen roller printing position. The cam  118  is fixed to a cam shaft  120  which is rotated about a cam shaft axis  113  by the lever  50  fixed to an end of the cam shaft  120  extending through the printer housing  2 .  
         [0056]    The elongated lever  50  has one end  124  fixed to the cam shaft  120 , and is pivotable about the cam shaft axis  113  (shown in FIGS. 11 and 12) between a lock position (shown in FIG. 13) and an unlock position (shown in FIG. 1). Pivoting the lever  50  about the cam shaft axis  113  between the lock and unlock positions, rotates the camshaft  120  to engage and disengage the cam  118  from the pivot linkage  104 . Advantageously, in the lock position, the lever opposed end  127  extends over the receptacle  18 , and engages the cartridge top wall shelf  48  to lock the cartridge  12  in the receptacle  18 . In the unlock position, the lever  50  is disengaged from the cartridge  12 , and allows the cartridge  12  into or out of the receptacle  18 . Preferably, the lever  50  includes a rib  122  extending along a lever edge to provide an engagement surface for a user to easily engage the lever  50  to pivot it about the cam shaft axis  113 .  
         [0057]    Referring back to FIGS. 7 and 8, the gear assembly  116  includes a plurality of intermeshed gears  114 ,  126 ,  128 ,  130 ,  132  rotatably mounted to the underside of the receptacle floor  78 . The gear assembly  116  is rotatably driven by a motor  134  fixed to the receptacle  18 . The motor  134  includes a shaft  136  which extends through the receptacle floor  78 , and has a pinion  138  fixed to the shaft  136  which meshes with the gear assembly  116 . The printer circuitry energizes the motor  134  to rotatably drive the shaft  136 , and thus the stationary gear  114 .  
         [0058]    One of the plurality of intermeshed gears  132  is fixed to and coaxial with the ink ribbon drive shaft  62  which extends through the receptacle floor  78  to rotatably drive the ink ribbon take up spool. Advantageously, the gear assembly  116  simultaneously drives the platen roller  24  and ink ribbon drive shaft  62  to synchronize the operation of the platen roller  24  and ink ribbon take up spool to smoothly urge the ink ribbon  16  (FIG. 6) and labeling media  14  (FIG. 6) along the web path.  
         [0059]    Referring to FIGS. 1, 4,  7 ,  11 , and  12 , once the cartridge  12  is locked in place, the platen roller  24  is in the printing position, and the drive gear  106  is engaged with the stationary gear  114 , the printing machine  10  is ready to produce printed labels. When printing on the labels, the platen roller  24  and a take up spool advance the labeling media  14  and ribbon  16  through the printing area  46  past the print head  22 . When a desired character is input by an operator or other means, the electronics of the machine  10  energizes pixels on the print head  22  as the labeling media  14  and ribbon  16  advance past the head  22 . The head pixels are variously energized to imprint the character on the labeling media  14 . This is described in greater detail in U.S. Pat. No. 5,078,523 which has been incorporated herein by reference.  
         [0060]    After printing, labeling media  14  advances to a “cut” position, at which time, the operator manually actuates the cutting mechanism  26  to separate the labeling media  14  containing printed labels from the unused portion. As shown in FIG. 3, the cutting mechanism  26  is disposed adjacent the printing mechanism  20  at the end of the web. Labeling media  14  fed into the cutting mechanism  26  is cut by a blade (not shown) disposed within the cutting mechanism  26 . The cut position exposes the printed labels to the operator through the printer housing slot  74 . Once the operator actuates the cutting mechanism  26 , the labels are retrieved by the operator for use.  
         [0061]    Referring now to FIGS. 1, 3,  5 , and  14 , in operation the printer  10  identifies the cartridge  12  by means of the electrical connection of the spring contacts  300 A,  300 B, and  300 C (FIGS. 3 and 14) with the conductive strip  302  (FIG. 5). Referring now specifically to FIGS. 3 and 14, the three spring contacts  300 A,  300 B, and  300 C are physically connected to an end of the circuit board  72 . When assembled in the printer  10 , the spring contacts  300 A,  300 B, and  300 C extend through slots  304 A,  304 B, and  304 C defined in the sidewall  76  of the cartridge receptacle  18 , respectively. The spring contacts  300 A,  300 B, and  300 C therefore extend axially into the cartridge receptacle  18 , and are located in the cartridge receptacle  18  such that they provide an electrical connection to the conductive strip  302  (FIG. 5) coupled to the cartridge sidewall  34  (FIG. 5) when the cartridge  12  is inserted into the cartridge receptacle  18 .  
         [0062]    Referring now to FIG. 15, each of the spring contacts  300  comprises a spring wire which is bent into three sections: a generally U-shaped mounting section  320 , a semi-circular portion  322 , and a contact portion  324 . Each of the legs  326  and  328  of the generally U-shaped mounting section  320  is directed through a through-hole  330  and  332  respectively of the printed circuit board  72 , while the flat section  334  of the generally U-shaped mounting section  320  rests in a slot  336  defined in the printed circuit board  72  between the through-holes  330  and  332 . Solder joints  338 ,  340  and  342  retain the spring contact  300  in the mounting holes  330  and  332  and associated slot  336 , provide an electrical connection between the spring contact  300  and the circuitry on the printed circuit board  72 , and provide structural stability as the contact end is elastically deformed when a cartridge  12  (FIG. 4) is inserted in the cartridge receptacle  18  (FIG. 7). The multiple solder joints  338 ,  340 , and  342  help to distribute force applied along the spring contact  300  through interaction with the conductive strip  302 , and further provide a redundant failure mechanism, wherein an electrical connection between the spring contact  300  and the printed circuit board  72  continues to be maintained even if one or more of the solder joints  338 ,  340 , and  342  is broken.  
         [0063]    The semi-circular portion  322  of the spring contact  300  extends downwardly from the bottom of the printed circuit board  72  and rearwardly to a point on the circuit board  72  substantially equivalent to the diameter of the semi-circular portion  322  from the through-hole  332 . The semi-circular section  322  provides structural stability to the spring contact, and does not provide an electrical connection. Therefore, the end  344  of the semi-circular portion  322  is not connected to the board.  
         [0064]    The contact portion  324  extends outwardly from the edge of the printed circuit board  72  such that the contact portion  324  can be inserted through the slots  304 A,  304 B and  304 C (all in FIG. 14) described above. The second end  346  of the spring contact  300  hangs loose allowing the contact portion  324  to elastically deform and expand as a force is applied i.e., as a cartridge  12  (FIG. 4) is inserted in the cartridge receptacle  18  (FIG. 7). The contact section  324  is also generally U-shaped and comprises three sections  360 ,  362 ,  364 : an upwardly extending section  360 , a generally downwardly extending section  362 , and a rearwardly extending section  364 . The upwardly extending section  360  is angled and includes a bend, such that the contact section  364  can pivot about this section as a force is applied. Electrical contact between the spring contact  300  and the printed circuit board is generally made to the downwardly extending section  364 , which provides a relatively large and flexible contact surface.  
         [0065]    Each of the spring contacts  300  is constructed of a music wire generally used in the construction of springs, and is preferably coated with a highly conductive layer. In the embodiment disclosed herein, the spring contacts  300  are constructed of a music wire having a diameter of 0.014 inches which is coated with an electrolytic nickel having a depth between two ten thousandths and three ten thousandths of an inch. Music wire is typically constructed of a high carbon steel wire having a high degree of elasticity, and is frequently used in the construction of small springs.  
         [0066]    Referring to FIGS.  3 - 7 , as noted above, when the cartridge  12  is inserted into the cartridge receptacle  18 , the conductive strip  302  is aligned with the spring contact  300 . The insertion of the cartridge  12  applies a force against the spring contacts  300 , causing the spring contacts  300  to provide a responsive spring force against the conductive strip  302 , and to contact the conductive strip  302  with a wiping motion, ensuring a good electrical connection between the conductive strip  302  and the spring contacts  300 . The ability to extend into the cartridge receptacle and contract as the cartridge is inserted is particularly important where, as shown above, the cartridge receptacle and cartridge include circular or circular elements as opposed to flat surfaces. Because the spring contacts can elastically expand and contract and provide a spring force against the conductive strip  302 , the electrical connection is not affected by minor variations in the size and diameter of the cartridge  12 , or in slight misalignments of the cartridge  12  in the cartridge receptacle  18 .  
         [0067]    Referring now to FIG. 16, the spring contacts  300 A and  300 C are coupled to a processing unit  312  which is electrically coupled to at least two of the spring contacts  300 A and  300 C by means of the input lines  310 A and  310 B respectively. Within the processing unit  312 , the input lines  310 A and  310 B are coupled to a peripheral interface device  316  which in turn directs signals received from the input lines  310 A and  310 B to a microprocessor  314 . The microprocessor  314  is programmed to determine the width of a labeling media  14  (FIG. 6) contained in a cartridge  12  (FIG. 6) inserted in the printer device  10  (FIG. 1) depending on whether the signals received on the input lines  310 A and  310 B are at reference potential or at a circuit common.  
         [0068]    Referring now to FIGS. 16 and 17, it can be seen that each of the spring contacts  300 A and  300 C are tied to a reference potential through a resistor  318 A and  318 B, respectively. The third spring contact  300 B is tied directly to circuit common. Therefore, each of the input lines  310 A and  310 B are normally held at the reference potential, and are pulled low to circuit common only when one of the spring contacts  300 A and  300 C is connected to the spring contact  300 B.  
         [0069]    Referring now to FIGS. 5, 16 and  18 - 20 , the conductive strip  302  which is coupled to the cartridge  12  provides three conductive contact pads  306 A,  306 B and  306 C which are physically aligned with the spring contacts  300 A,  300 B and  300 C in the cartridge receptacle  18  (FIG. 7) thereby providing an electrical connection between the conductive contact pad  306 A,  306 B,  306 C, and the spring contacts  300 A,  300 B, and  300 C, respectively. The conductive strip  302  further comprises traces  308 A and  308 B, which selectively tie the contacts  306 A and  306 C to the contact  306 B. The traces  308 A and  308 B selectively pull the input lines  310 A and  310 B to a circuit common, thereby providing input data to the microprocessor  314 , which is programmed to determine a width of the labeling media  14  (FIG. 6) in the inserted cartridge  12  (FIG. 6) based on this data, as described more fully below.  
         [0070]    Referring now specifically to FIGS.  16 - 20  and to Table 1, below, three possible configurations of the conductive strip  302  are shown. Referring first to FIG. 18, in a first configuration, hereafter referred to as conductive strip  302 A, the contact  306 A is tied to the contact  306 B through the trace  308 A. When the conductive strip  302 A is electrically coupled to the contacts  300 A,  300 B, and  300 C, the spring contact  300 A is tied to contact  300 B through the contact  306 A, the trace  308 A and the contact  306 B. Microprocessor  314  senses that the input line  310 A has been pulled to circuit common while the input line remains  310 B at reference potential. The microprocessor  314  determines a width of a tape or other labeling media  14  (FIG. 6) based on this input data, as shown in row 1 of Table 1. In a second configuration of conductive strip  302 B shown in FIG. 19, the trace  308 B electrically couples the contact  306 C to the contact  306 B. In a similar manner as described above and as shown in row 2 of Table 1, the input line  310 B is pulled to circuit common while the input line  310 A remains at reference potential. In the conductive strip  302 C of FIG. 20 both of the input lines  310 A and  310 B are pulled to circuit common as shown in row 3 of Table 1, below. If a cartridge  12  (FIG. 6) is not inserted in the cartridge receptacle  18  (FIG. 7), both of the input lines  310 A and  310 B are at reference potential, as shown in row 4 of Table 1.  
                                                   TABLE 1                           Characteristics identified with three contacts and three cartridge PCB&#39;s.                310A   310B   What does it tell the Printer?                        302A   0   1   Tape media width #1       302B   1   0   Tape media width #2       302C   0   0   Tape media width #3       No Connection   1   1   Cartridge is not inserted                  
 
         [0071]    While there has been shown and described what are at present considered the preferred embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention defined by the appended claims. For example, although a microprocessor and associated peripheral interface device have been shown, it will be apparent that a number of available types of processing units could be used, including microprocessors, microcontrollers, and other logical operators. These devices can be used in conjunction with a peripheral device, as shown above, or through a direct connection to the contacts. Furthermore, although a specific spring contact construction has been shown, it will be apparent that modifications can be made thereto while still providing the required functionality. For example, the number of contacts and associated logical operations can be varied depending on the number and type of labeling media characteristics to be determined. Also, although the conductive strip  302  is shown adhesively coupled to the cartridge  12 , other methods of coupling the conductive strip  302  to the cartridge will be apparent to those of ordinary skill in the art. Furthermore, although a printed circuit board comprising electrical conductive pads and associated pads has been shown, it will be apparent that conductors of various types and varieties can be used to electrically couple the spring contacts together, including, for example, conductive or metallized tape that does not include defined pads and connecting traces.