Patent Publication Number: US-6213659-B1

Title: Print medium loading error detection for use in printing devices

Description:
BACKGROUND AND SUMMARY 
     The present invention relates to printing devices. More particularly, the present invention relates to an apparatus and method for detecting error in loading a print medium in a printing device. 
     Printing devices, such as inkjet printers and laser printers, use printing composition (e.g., ink or toner) to print text, graphics, images, etc. onto a print medium. Inkjet printers may use print cartridges, also known as “pens”, which shoot drops of printing composition, referred to generally herein as “ink”, onto a print medium such as paper, transparencies or cloth. Each pen has a printhead that includes a plurality of nozzles. Each nozzle has an orifice through which the drops are fired. To print an image, the printhead is propelled back and forth across the page by, for example, a carriage while shooting drops of ink in a desired pattern as the printhead moves. The particular ink ejection mechanism within the printhead may take on a variety of different forms known to those skilled in the art, such as thermal printhead technology. 
     In a current thermal system, a barrier layer containing ink channels and vaporization chambers is located between an orifice plate and a substrate layer. This substrate layer typically contains linear arrays of heating elements, such as resistors, which are energized to heat ink within the vaporization chambers. Upon heating, the ink in the vaporization chamber turns into a gaseous state and forces or ejects an ink drop from an orifice associated with the energized resistor. By selectively energizing the resistors as the printhead moves across the print medium, ink is expelled in a pattern on to the print medium to form a desired image (e.g. picture, chart and/or text). 
     Printing devices typically include one or more print media input devices, such as input trays for sheets of print media or input racks for rolls of print media. These input trays and input racks usually include means to adjust for the particular width and/or length of the print media to help assure proper registration of the print media in the input tray or on the input rack. Proper registration in turn helps ensure that print media is fed into the print zone of a printing device in the correct alignment so that the printed image is properly oriented on the print media which helps achieve high-quality printed output by the printing device. 
     The means to adjust for the particular width and/or length of the print medium includes a print medium width adjuster and/or a print medium length adjuster. The positions of such print medium width adjusters and a print medium length adjusters may be varied through a range of predetermined distances, either manually or mechanically, so that such adjusters abut against the print medium. 
     If a user of a printing device improperly positions either the print medium width adjuster or the print medium length adjuster, then the print medium may be incorrectly fed into the print zone of the printing device such that the printed image is improperly oriented on the print medium, producing less than optimal output print quality. In some cases, the printed output may be partially or completely illegible. Improper positioning of either the print medium width adjuster or print medium length adjuster may also lead to jamming of the printing device during transport of the print medium to the print zone which requires user intervention to clear the jam and decreases printing device throughput, both of which are undesirable. Improper positioning of either the print medium width adjuster or print medium length adjuster may further lead to wasted print medium caused by such poor printing device output print quality and jamming, both of which can be expensive. 
     Alleviation of these problems would be a welcome improvement, thereby helping to maintain optimal printing device output print quality, prevent print medium jamming, optimize printing device throughput, minimize necessary user intervention, and prevent waste of print media. Accordingly, the present invention is directed to solving printing device problems caused by improper positioning of either the print medium width adjuster or print medium length adjuster. The present invention accomplishes this objective by providing an apparatus and method for detecting error in loading a print medium in a printing device. 
     An embodiment of a method in accordance with the present invention for use in a printing device includes determining a position of a print medium width adjuster and measuring a width of a print medium. The method additionally includes comparing the print medium width adjuster position with the determined print media width and prompting a user of the printing device to properly position the print medium width adjuster in instances where the print medium width adjuster is improperly positioned for the determined print media width. 
     The above-described embodiment of a method in accordance with the present invention may be modified and include the following, as described below. The method may additionally include determining a position of a print medium length adjuster and measuring a length of the print medium. In such cases, the method additionally includes comparing the print medium length adjuster position with the determined print medium length and prompting a user of the printing device to properly position the print medium length adjuster in instances where the print media length adjuster is improperly positioned for the determined print medium length. 
     An alternative embodiment of a method in accordance with the present invention includes determining a position of a print medium length adjuster and measuring a length of a print medium. The method additionally includes comparing the print medium length adjuster position with the determined print medium length and prompting a user of the printing device to properly position the print medium length adjuster in instances where the print medium length adjuster is improperly positioned for the determined print medium length. 
     An embodiment of an apparatus in accordance with the present invention for use in a printing device includes a print medium width adjuster sensor configured to determine a position of a print medium width adjuster. The apparatus also includes a width sensor configured to measure a width of a print medium. The apparatus further includes a computing device configured both to compare the print medium width adjuster position determined by the print medium width adjuster position sensor with the print medium width measured by the width sensor, and to verify that the print medium width adjuster is properly positioned for the determined print media width. 
     The above-described embodiment of an apparatus in accordance with the present invention may be modified and include the following characteristics, as described below. The apparatus may additionally include a print medium length adjuster position sensor configured to determine a position of a print medium length adjuster and a length sensor configured to measure a length of the print medium. In such cases, the computing device is additionally configured both to compare the print medium length adjuster position determined by the print medium length adjuster position sensor with the print medium length measured by the length sensor, and to verify that the print medium length adjuster is properly positioned for the determined print medium length. 
     The length sensor may include a print medium axis position quadrature encoder. The length sensor may additionally or alternatively include a flag configured to be actuated by the print medium. 
     The width sensor may include a printing device carriage position quadrature encoder. 
     An alternative embodiment of an apparatus in accordance with the present invention for use in a printing device includes a print medium length adjuster position sensor configured to determine a position of a print medium length adjuster. The apparatus also includes a length sensor configured to measure a length of a print medium. The apparatus further includes a computing device configured both to compare the print medium length adjuster position determined by the print medium length adjuster position sensor with the print medium length measured by the length sensor, and to verify that the print medium length adjuster is properly positioned for the determined print medium length. 
     The above-described alternative embodiment of an apparatus in accordance with the present invention may be modified to include the following characteristics, as described below. The length sensor may include a print medium axis position quadrature encoder. The length sensor may additionally or alternatively include a flag configured to be actuated by the print medium. 
     Another alternative embodiment of an apparatus in accordance with the present invention for use in a printing device includes structure for determining a position of a print medium width adjuster and structure for measuring a width of a print medium. The apparatus additionally includes structure for comparing the print medium width adjuster position with the determined print media width and structure for prompting a user of the printing device to properly position the print medium width adjuster when the print medium width adjuster position differs from the determined print medium width. 
     The above-described additional alternative embodiment of an apparatus in accordance with the present invention may be modified to include the following characteristics, as described below. The apparatus may further include structure for determining a position of a print medium length adjuster and structure for measuring a length of the print medium. In such cases, the apparatus further includes structure for prompting a user of the printing device to properly position the print medium length adjuster when the print medium length adjuster position differs from the determined print medium length. 
     A still further alternative embodiment of apparatus in accordance with the present invention for use in a printing device includes structure for determining a position of a print medium length adjuster and structure for measuring a length of a print medium. The apparatus additionally includes structure for comparing the print medium length adjuster position with the determined print medium length and structure for prompting a user of the printing device to properly position the print medium length adjuster when the print medium length adjuster position differs from the determined print medium length. 
     Other objects, advantages, and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a printing device that includes an embodiment of the present invention. 
     FIG. 2 is a perspective view of an input tray having a manually repositionable print medium width adjuster and a manually repositionable print medium length adjuster. 
     FIG. 3 is a perspective view of a print medium length sensor in accordance with the present invention configured to measure a length of a print medium. 
     FIG. 4 is a side view of a print medium width sensor in accordance with the present invention configured to measure a width of a print medium. 
     FIG. 5 is a schematic block diagram of an embodiment of an apparatus in accordance with the present invention. 
     FIG. 6 is a flow chart of an embodiment of a method in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates an embodiment of an inkjet printing device  20 , here shown as an a “off-axis” inkjet printer, constructed in accordance with the present invention, which may be used for printing business reports, correspondence, desktop publishing, and the like, in an industrial, office, home or other environment. A variety of inkjet printing devices are commercially available. For instance, some of the printing devices that may embody the present invention include plotters, portable printing units, copiers, cameras, video printers, and facsimile machines, to name a few, as well as various combination devices, such as combination facsimiles and printers. In addition, the present invention may be used in other types of printing devices such as “on-axis” inkjet printers, dot matrix printers, and laser jet printers. For convenience, the concepts of the present invention are illustrated in the environment of inkjet printer  20 . 
     While printing device components may vary from model to model, a typical inkjet printer  20  includes a frame or chassis  22  surrounded by a housing, casing or enclosure  24 , typically made of a plastic material. Sheets of print media are fed through a printzone  25  by a print media handling system  26 . The print media may be any type of suitable material, such as paper, card-stock, transparencies, photographic paper, fabric, metalized media, etc. Print media handling system  26  includes an input tray  28  for storing sheets of print media for printing. A series of conventional print media drive rollers  30  rotate about a shaft  31  which is driven by a motor  35  through a series of drive gears  33  and  34 . Gears  33  and  34  are rotateably coupled to shaft  31  to rotate shaft  31  in a direction generally indicated by arrow  93 . Drive rollers  30  are used to move print medium from input tray  28 , through printzone  25  and, after printing, onto a pair of extendable output drying wing members  36 , shown in a retracted or rest position in FIG. 1 . Wings  36  momentarily hold a newly printed sheet of print media above any previously printed sheets still drying in an output tray  37 . Print media handling system  26  also includes means for accommodating different sizes of print media, including letter, legal, A-4, B, envelopes, etc. This means includes a print medium length adjuster  38  and a print medium width adjuster  39 . As discussed below in connection with FIG. 2, print medium length adjuster  38  and print medium width adjuster  39  are manually repositionable against the sides of different sizes of print medium, and thereby accommodate for these different sizes. An envelope feed port  29  may be used in lieu of repositioning print medium length adjuster  38  and print medium width adjuster  39  to accommodate for the smaller size of such envelopes. Although not shown, it is to be understood that print media handling system  26  may also include other items such as one or more additional input trays. Additionally, print media handling system  26  and printing device  20  may be configured to support specific print tasks such as duplex printing (i.e., printing on both sides of the sheet of print media) and banner printing. 
     Printing device  20  also has a computing device  40 , illustrated as a microprocessor or controller, that receives instructions from a host device, typically a computer, such as a personal computer (not shown). Many of the functions of computing device  40  may be performed by a host computer, including any printing device drivers resident on the host computer, by electronics in the printing device, or by interactions between the host computer and the electronics. As used herein, the term “computing device  40 ” encompass these functions, whether performed by a host computer, printing device  20 , an intermediary device between the host computer and printing device  20 , or by combined interaction of such elements. Computing device  40  may also operate in response to user inputs provided through a keypad  42  located on the exterior of casing  24 . A monitor (not shown) coupled to the computer host may be used to display visual information to a user of printing device  20 , such as the printer status or a particular program being run on the host computer. Personal computers, input devices, such as a keyboard and/or a mouse device, and monitors are all known to those skilled the art. 
     A carriage guide rod  44  is supported by chassis  22  to slideably support an off-axis inkjet carriage  45  for travel back and forth across printzone  25  along a scanning axis generally designated by arrow  46  in FIG.  1 . As can be seen in FIG. 1, scanning axis  46  is substantially parallel to be X-axis of the XYZ coordinate system shown in FIG.  1 . It should be noted that the use of the words substantially in this document is used to account for things such as engineering and manufacturing tolerances, as well as variations not affecting performance of the present invention. Carriage  45  is also propelled along guide rod  44  into a servicing region, generally indicated by arrow  48 , located within the interior of housing  24  of printing device  20 . A conventional carriage drive gear and motor assembly (both of which are not shown in FIG. 1) may be coupled to drive an endless loop, which may be secured in a conventional manner to carriage  45 , with the motor operating in response to control signals received from a computing device  40  to incrementally advanced carriage  45  along guide rod  44  in response to movement of the motor. 
     In printzone  25 , a sheet of print medium receives ink from an inkjet cartridge, such as black ink cartridge  50  and three monochrome color ink cartridges  52 ,  54 , and  56 . Cartridges  50 ,  52 ,  54 , and  56  are also called “pens” by those skill the art. Pens  50 ,  52 ,  54 , and  56  each include small reservoirs for storing a supply of printing composition, referred to generally herein as “ink” in what is known as an “off-axis” ink delivery system, which is in contrast to a replaceable ink cartridge system where each pen has a reservoir that carries the entire ink supply as the printhead reciprocates over printzone  25  along carriage scan axis  46 . The replaceable ink cartridge system may be considered an “on-axis” system, whereas systems which store the main ink supply at a stationary location remote from the printzone scanning axis are called “off-axis” systems. It should be noted that the present invention is operable in both off-axis and on-axis systems. 
     In the illustrated off-axis printing device  20 , ink of each color from each printhead is delivered via a conduit or tubing system  58  from a group of main ink reservoirs  60 ,  62 ,  64 , and  66  to the on-board reservoirs of respective pens  50 ,  52 ,  54 , and  56 . Ink reservoirs  60 ,  62 ,  64 , and  66  are replaceable ink supplies stored in a receptacle  68  supported by printer chassis  22 . Each of pens  50 ,  52 ,  54 , and  56  has a respective printhead, as generally indicated by arrows  70 ,  72 ,  74 , and  76 , which selectively ejects ink to form an image on a print medium in printzone  25 . 
     Printheads  70 , 72 ,  74 , and  76  each have an orifice plate with a plurality of nozzles formed therethrough in a manner well-known to those skill the art. The illustrated printheads  70 , 72 ,  74 , and  76  are thermal inkjet printheads, although other types of printheads may be used, such as piezoelectric printheads. Thermal printheads  70 , 72 ,  74 , and  76  typically include a plurality of resistors which are associated with the nozzles. Upon energizing a selected resistor, a bubble of gas is formed which ejects a droplet of ink from the nozzle onto the print medium in printzone  25  under the nozzle. The printhead resistors are selectively energized in response to firing command control signals delivered by a multi-conductor strip  78  (a portion of which is shown in FIG. 1) from computing device  40  to printhead carriage  45 . 
     An optical quadrature encoder strip  80  extends along the length of printzone  25  and over the area of service station region  48  to provide carriage  45  positional feedback information to computing device  40 , with a carriage position quadrature encoder reader  82  (see FIG. 4) being mounted on a back surface of printhead carriage  45  to read positional information provided by optical quadrature encoder strip  80 . Together, optical quadrature  30  encoder strip  80  and carriage position quadrature encoder reader  82  constitute a printing device carriage position quadrature encoder. Printing device  20  uses optical quadrature encoder strip  80  and the carriage position quadrature encoder reader  82  to trigger the firing of printheads  70 , 72 ,  74 , and  76 , to provide feedback for position and velocity of carriage  45 , and to measure the width of a print medium, as discussed more fully below in connection with FIG.  4 . 
     Optical encoder strip  80  may be made from things such as photo imaged MYLAR brand film, and works with a light source and a light detector (both of which are not shown) of carriage position quadrature encoder reader  82 . The light source directs light through strip  80  which is received by the light detector and converted into an electrical signal which is used by computing device  40  of printing device  20  to control firing of printheads  70 ,  72 ,  74 , and  76 , to control carriage  45  position and velocity, and to measure the width of a sheet of print medium, as discussed more fully below in connection with FIG.  4 . Markings or indicia on encoder strip  80  periodically block this light from the light detector of carriage position quadrature encoder reader  82  in a predetermined manner which results in a corresponding change in the electrical signal from the detector of carriage position quadrature encoder reader  82  which is processed by computing device  40 . 
     A print medium axis position quadrature encoder  84  is also shown in FIG.  1 . Print medium axis position quadrature encoder  84  provides positional feedback information to computing device  40  regarding the position of print media drive rollers  30  and also provides data, in combination with flag  86 , to computing device  40  so that the length of a print medium can be measured, as discussed below in connection with FIG.  3 . Printing device  20  uses print medium axis position quadrature encoder  84  to help accurately position print medium in printzone  25 , to control printing by one or more of printheads  70 ,  72 ,  74 , and  76 , and to measure the length of print medium, as discussed more fully below in connection with FIG.  3 . Print medium axis position quadrature encoder  84  includes a rotary encoder  88  and a pair of rotary encoder readers  90  and  92 . Rotary encoder  88  is coupled to shaft  31  to rotate therewith in the direction generally indicated by arrow  93 . 
     Rotary encoder  88  may be made from things such as photo imaged MYLAR brand film, and works with a light source and a light detector (both of which are not shown) of each of rotary encoder readers  90  and  92 . These light sources direct light through rotary encoder  88  which is received by the light detectors and converted into an electrical signal which is used by computing device  40  of printing device  20  to help accurately position print medium in printzone  25 , to control firing of printheads  70 ,  72 ,  74 , and  76 , and to measure the length of print medium, as discussed more fully below in connection with FIG.  3 . Markings or indicia on rotary encoder  88  periodically block this light from the light detectors of rotary encoder readers  90  and  92  in a predetermined manner which results in a corresponding change in the electrical signal from the detectors of rotary encoder readers  90  and  92  which is processed by computing device  40 . 
     A perspective view of input tray  28  with manually repositionable print medium length adjuster  38  and a manually repositionable print medium width adjuster  39  is shown in FIG.  2 . As can be seen in FIG. 2, print medium length adjuster  38  includes a handle portion  94  for manual grasping that is coupled to a base portion  96 . Input tray  28  in turn is formed to include a track  98  of a predetermined length that is sized to slideably receive base portion  96  of print medium length adjuster  38 . In this way, print medium length adjuster  38  is manually repositionable along the length of track  98  in the directions indicated by double-headed arrow  100  so that input tray  28  can accommodate for a variety of different lengths of print medium by placing handle portion  94  against a side of the print medium. 
     As can also be seen in FIG. 2, print medium width adjuster  39  includes a handle portion  102  that is coupled to base portions  104  and  106 . Input tray  28  in turn is formed to include tracks  108  and  110  each of a predetermined length that are sized to slideably receive base portions  104  and  106  of print medium width adjuster  39 . In this way, print medium width adjuster  39  is manually repositionable along the lengths of tracks  108  and  110  in the directions indicated by double-headed arrow  112  so that input tray  28  can accommodate for a variety of different widths of print medium by placing handle portion  102  against a side of the print medium. 
     In operation of printing device  20 , print medium length adjuster  38  and print medium width adjuster  39  should be positioned against the sides of a print medium in input tray  28  to help assure proper registration of the print medium against respective walls  114  and  116  of input tray  28 . Such registration in turn helps assure proper transport by print media handling system  26  from input tray  28  to printzone  25 . 
     A perspective view of a print medium length sensor  118  constructed in accordance with the present invention is shown in FIG.  3 . Print medium length sensor  118  is configured to measure a length of different sizes of print medium transported by print medium handling system  26  from input tray  28  to printzone  25 , such as the length of print medium  120 . As can be seen in FIG. 3, print medium length sensor  118  includes print medium axis position quadrature encoder  84  and flag  86  which is schematically illustrated in FIG.  3 . 
     In operation, print medium  120  is transported from input tray  28  to printzone  25  by print media handling system  26  in a direction generally indicated by arrow  122 . Prior to entering printzone  25 , side  124  of print medium  120  contacts angled edge  126  of flag  86  which actuates flag  86  about pivot  128  in the direction shown by arrow  130 . Actuation of flag  86  about pivot  128  in the direction of arrow  130  signals computing device  40  to begin tracking rotation of rotary encoder  88  in the direction generally indicated by arrow  93  via rotary encoder readers  90  and  92 . Flag  86  remains in this position until edge  132  of print medium  120  clears angled edge  126 , at which point flag  86  returns to its original position which signals computing device  40  to cease tracking rotation of rotary encoder  88  via rotary encoder readers  90  and  92 . Computing device  40  can then calculate the length of print medium  120  by using the length of the diameter of drive rollers  30  and the number of turns of rotary encoder  88  between edges  124  and  132  via the formula: 
     
       
         Print Medium Length=(Number of Rotations)×C drive rollers 30 =(Number of Rotations)×π×d drive rollers 30 , 
       
     
     where (Number of Rotations) is the number of rotations of rotary encoder  88 , (C) is the circumference of drive rollers  30 , and (d) is the diameter of drive rollers  30 . For example, if d=1.0000 inches, Number of Rotations=3.5014, then: 
     
       
         Print Medium Length=(3.5014)×(π)×(1.000)=11 inches. 
       
     
     A side view of a print medium width sensor  134  constructed in accordance with the present invention is shown in FIG.  4 . Print medium width sensor  134  is configured to measure a width of different sizes of print medium transported by print medium handling system  26  from input tray  28  to printzone  25 , such as the width of print medium  120 . As can be seen in FIG. 4, print medium width sensor  134  includes optical quadrature encoder strip  80 , carriage position quadrature encoder reader  82 , and a print medium side detector  136 . 
     In operation, print medium  120  is transported from input tray  28  to printzone  25  by print media handling system  26  in a direction generally indicated by arrow  122 , as discussed above in connection with FIG.  3 . Prior to entering printzone  25 , carriage  45  is moved in the direction of arrow  140  so that side  138  of print medium  120  is detected by beam  142  of print medium side detector  136 . Detection of side  138  of print medium  120  signals computing device  40  to begin measuring the distance traveled by carriage  45  in the direction of arrow  140  by recording the position shown on optical quadrature encoder strip  80 . Carriage  45  continues movement in the direction of arrow  140  until side  144  of print medium  120  is detected by print medium side detector  136  of print medium width sensor  134  at which point computing device  40  ceases to measure the distance traveled by carriage  45 . Computing device  40  can then calculate the width of print medium  120  which is equal to the distance traveled by carriage  45  as measured by optical quadrature encoder strip  80  and carriage position quadrature encoder reader  82 . 
     As discussed above, ideally print medium width adjuster  39  should be positioned against one of the sides of a print medium in input tray  28  to help assure proper registration of the print medium against wall  116  of input tray  28 . Such registration in turn helps assure proper transport by print media handling system  26  from input tray  28  to printzone  25 . If either print medium length adjuster  38  or print medium width adjuster  39  is not positioned against one of the sides of the print medium, then the print medium may not be properly registered. Such improper registration can cause the print medium to be incorrectly fed into the print zone of a printing device such that the printed image is improperly oriented on the print medium, producing less than optimal output print quality. In some cases, the printed output may be partially or completely illegible. Improper positioning of either print medium length adjuster  38  or print medium width adjuster  39  may also lead to jamming of printing device  20  during transport of the print medium to print zone  25  which requires user intervention and decreases printing device  20  throughput, both of which are undesirable. Improper positioning of either print medium length adjuster  38  or print medium width adjuster  39  may further lead to wasted print medium caused by such poor printing device  20  output print quality and jamming which can be expensive. The present invention is directed to solving printing device  20  problems caused by improper positioning of either the print medium length adjuster  38  or print medium width adjuster  39 . 
     A schematic block diagram of an embodiment of an apparatus for detecting error in loading print medium in a printing device  146  in accordance with the present invention is shown in FIG.  5 . As can be seen in FIG. 5, apparatus  146  includes a print medium width adjuster position sensor  148  that is electrically coupled to computing device  40 . Print medium width adjuster position sensor  148  determines the position of print medium width adjuster  39  in input tray  28 . 
     Print medium width adjuster position sensor  148  may be configured in a variety of different ways including both electrically or optically. For example, an electrical configuration could include the use of a potentiometer consisting of electrical contacts on the bottom of at least one of bases  104  or  106  and a corresponding electrical contact along the length of either or both of respective tracks  108  and  110 . Depending on the particular configuration, one end of either or both of tracks  108  and  110  could be connected to a voltage and the other end connected to ground. For the particular location of print medium width adjuster  39 , the value of the resistance at either or both of bases  104  and  106  could then be measured and interpreted by computing device  40  to determine the position of print medium width adjuster  39 . An optical configuration could include the use of emitter/detector pairs on base  104  and track  108 , and additionally or alternatively on base  106  and track  110 . 
     As can also be seen in FIG. 5, apparatus  146  additionally includes a print medium length adjuster position sensor  150  that is electrically coupled to computing device  40 . Print medium length adjuster position sensor  150  determines the position of print medium length adjuster  38  in input tray  28 . 
     Print medium length adjuster position sensor  150  may be configured in a variety of different ways including both electrically or optically. For example, an electrical configuration could include the use of a potentiometer consisting of electrical contacts on the bottom of base  96  and a corresponding electrical contact along the length of track  98 . One end of track  98  could be connected to a voltage and the other end connected to ground. For the particular location of print medium length adjuster  38 , the value of the resistance at base  96  could then be measured and interpreted by computing device  40  to determine the position of print medium length adjuster  38 . An optical configuration could include the use of an emitter/detector pair on base  96  and track  98 . 
     As can additionally be seen in FIG. 5, apparatus  146  includes print medium width sensor  134  that is electrically coupled to computing device  40  and was discussed above in connection with FIG.  4 . As can further be seen in FIG. 5, apparatus  146  also includes a print medium length sensor  118  that is electrically coupled to computing device  40  and was discussed above in connection with FIG.  3 . In accordance with the present invention, computing device  40  is configured to utilize the data provided by sensors  118 ,  134 ,  148 , and  150  to detect error in loading print medium in printing device  20 , as discussed more fully below in connection with FIG. 6, and output any detected error through a user interface  152 , such a display (not shown) of printing device  20  or monitor coupled to a computer host (also not shown). 
     A flow chart of an embodiment of a method for detecting error in loading print medium in a printing device  154  in accordance with the present invention is shown in FIG.  6 . As can be seen in FIG. 6, method  154  includes determination of the print medium width adjuster position  156  by the above-described print medium width adjuster position sensor  148  and determination of the print medium length adjuster position  158  by the above-described print medium length adjuster position sensor  150 . Method  154  additionally includes measurement of the print medium width  160  by the above-described print medium width sensor  134  and measurement of the print medium length  162  by the above-described print medium length sensor  118 . 
     Next, the print medium width adjuster position is compared with the measured print medium width  164  and a determination made as to whether the print medium width adjuster position and the print medium width are the same  166 . If they are the same, then print medium width adjuster  39  is properly positioned against a side of the print medium helping to properly register the print medium for transport by print media handling system  26 , and the print medium length adjuster position is next compared with the measured print medium length  168 . If not, then the user of printing device  20  is prompted via user interface  152  to properly position print medium width adjuster  39  as indicated at  176 , and the print medium width adjuster position again determined  156 , as shown. 
     Once print medium width adjuster  39  has been properly positioned, the print medium length adjuster position is compared with the measured print medium length  168 , and a determination is made as to whether the print medium length adjuster position and the print medium length are the same  171 . If they are the same, then print medium length adjuster  38  is properly positioned against a side of the print medium helping to properly register the print medium for transport by print media handling system  26 , and method  154  ends  172 . If not, then the user of printing device  20  is prompted via user interface  152  to properly position print medium length adjuster  38  as indicated at  174 , and the print medium length adjuster position again determined  158 , as shown. The method continues until print medium length adjuster  38  is properly positioned against a side of the print medium. 
     Although the invention has been described and illustrated in detail, it is to be clearly understood that the same is intended by way of illustration and example only, and is not to be taken necessarily, unless otherwise stated, as an express limitation. For example, alternative embodiments of apparatuses and methods in accordance with the present invention may only determine proper position of either print medium length adjuster  38  or print medium width adjuster  39 , rather than both as discussed above. The spirit and scope of the present invention are to be limited only by the terms of the following claims.