Abstract:
Hand-held printers are disclosed that include a housing, a printhead, a controller and at least one position sensor to capture location data as the printer is manually moved across the media. In the described embodiments, the controller uses location data received from the one or more sensors to discern the printer location and reference indicia are used to direct a user to move the printer in a given direction.

Description:
FIELD OF THE INVENTION 
       [0001]    Generally, the present invention relates to handheld printers. Particularly, it relates to improving print quality in handheld printers of the type able to print in random motion patterns. In one aspect, reference indicia on media are used to relocate a lost printer position and/or update (validate) printer position while either inactive or actively printing. In another, particular types and styles of reference indicia are contemplated. Still other aspects relate to media having reference indicia and supply items with reference indicia for use with the media. 
       BACKGROUND OF THE INVENTION 
       [0002]    As is known, handheld printers afford mobile convenience to users. Unlike their immobile or stationary counterparts, users determine the navigation path of a given swath of printing. In some instances, this includes random movement over a media. In others, it includes back-and-forth movement attempting to simulate a stationary printer. Regardless, successful handheld printing dictates that image information relative to the printer location be available at all times. However, all users do not navigate in the same fashion. Nor do they navigate at the same speed or orientation. For at least these reasons, handheld printers rely heavily on sensor inputs, such as those from optical sensors or encoders, for printing images. Yet, sensor inputs are sometimes limited to their capabilities and print jobs are interrupted due to lost or inaccurate printer location calculations. 
         [0003]    In turn, if the printer location ever becomes lost, the printer can either quit printing or guess at location. If printing quits, users have incomplete print jobs. If locations are guessed, print quality suffers. In either, poor results are obtained. In the event printer locations are not completely lost, but simply inaccurate, print quality suffers because of inappropriately placed print patterns being deposited on the media. 
         [0004]    Accordingly, there exists a need in the art for robust, multi-directional and random printing handheld printer having improved print quality. Particularly, there are needs by which handheld printers are able to validate or recalibrate positioning during printing and/or reacquire positioning to complete an interrupted or lost print job. Naturally, any improvements should further contemplate good engineering practices, such as relative inexpensiveness, stability, low complexity, ease of manufacturing, etc. 
       SUMMARY OF THE INVENTION 
       [0005]    The above-mentioned and other problems become solved by applying the principles and teachings associated with the hereinafter described handheld printing with reference indicia. Specifically, methods and apparatus contemplate handheld printers manipulated randomly or predictably over a media on which an image is printed. In this regard, various reference indicia on the media serve to assist in reacquiring a lost printer position or validate/update other positions. 
         [0006]    Representatively, a handheld printer includes one or more position sensors, a controller and an inkjet printhead that are coordinated to print an image. Also, the controller correlates the location of the printhead to the image and, when lost, communicates to a direction indicator of the printer to provide user notification of where to move the housing to reacquire the location. Especially, the direction indicator points to the location of a reference indicia on the media. Once over the reference indicia, the printer reads or views the information therein and location is reacquired. Embodiments of the reference indicia include guide and location patterns, with the guide pattern pointing to the location pattern. The reference indicia is variously provided, but representatively includes being printed by the printer as printing operations begin, being pre-printed on the media or applied to the media as a supply item. 
         [0007]    For validating or recalibrating other than completely lost positions, reference indicia representatively include related tick marks of substantially equal size and shape with substantially equal spacing there between. 
         [0008]    Supply items for applying reference indicia on the media include a substrate with reference indicia thereon. The substrate has a planar size substantially smaller than the media. The reference indicia is also pre-selected to substantially match a reference indicia stored in the printer. 
         [0009]    These and other embodiments, aspects, advantages, and features of the present invention will be set forth in the description which follows, and in part will become apparent to those of ordinary skill in the art by reference to the following description of the invention and referenced drawings or by practice of the invention. The aspects, advantages, and features of the invention are realized and attained by means of the instrumentalities, procedures, and combinations particularly pointed out in the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The accompanying drawings incorporated in and forming a part of the specification, illustrate several aspects of the present invention, and together with the description serve to explain the principles of the invention. In the drawings: 
           [0011]      FIG. 1  is a diagrammatic view in accordance with the present invention of a handheld printer; 
           [0012]      FIG. 2  is a diagrammatic view in accordance with the present invention of a representative inkjet printhead for use in the handheld printer of  FIG. 1 ; 
           [0013]      FIG. 3  is a diagrammatic view in accordance with the present invention of a representative arrangement of a handheld printer for printing with reference indicia; 
           [0014]      FIG. 4  is a diagrammatic view in accordance with the present invention of a representative reference indicia for use in reacquiring printer location; 
           [0015]      FIG. 5  is a flow chart in accordance with the present invention of a representative method for printing with reference indicia; 
           [0016]      FIG. 6  is a flow chart in accordance with the present invention of an alternate embodiment for printing with reference indicia; 
           [0017]      FIGS. 7A-7G  are diagrammatic views in accordance with the present invention of a representative media and/or supply item with reference indicia for use in handheld printing; and 
           [0018]      FIG. 8  is a cross section view in accordance with the present invention of a representative supply item with reference indicia for use with media in handheld printing. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0019]    In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention and like numerals represent like details in the various figures. Also, it is to be understood that other embodiments may be utilized and that process, mechanical, electrical and/or other changes may be made without departing from the scope of the present invention. In accordance with the present invention, a handheld printer for printing with reference indicia is hereafter described. 
         [0020]    With reference to  FIG. 1 , a handheld printer of the invention for printing with one or more reference indicia  11  is given generically as  10 . It includes a housing  14  that an operator  12  maneuvers or manipulates back and forth over a media  16  to print an image  18 . In various embodiments, the image is text, figures, combinations of text and figures or the like. They are typified in color and/or black and white. Also, the printer optionally includes position indicators  17  that, as will be seen below, notify users where to move the housing to pass over the reference indicia to reacquire a lost printer position or validate an existing position. The indicators are representatively given as arrows and may be found electronically as part of a viewable display panel  19  (dashed line) or physically as structures, such as lighted buttons. 
         [0021]    In  FIG. 2 , an inkjet printhead of the printer internal to the housing [ 14 ] is shown generally as  110 . It includes its own housing  112  having a shape that depends upon the shape of the printer. The housing has at least one internal compartment  116  for holding an initial or refillable supply of ink. In one embodiment, the compartment contemplates a single chamber holding a supply of black, cyan, magenta or yellow ink. In other embodiments, it contemplates multiple chambers containing multiple different colored inks. In one instance, it includes supplies of cyan, magenta and yellow ink. In still other embodiments, it includes plurals of black, cyan, magenta and/or yellow ink. It will be appreciated, however, that while the compartment  116  is shown as locally integrated within a housing  112  of the printhead, it may alternatively be separable from the housing  112  and/or printhead  110 , for example. 
         [0022]    At one surface  118  of the housing  112  is a portion  119  of a flexible circuit, especially a tape automated bond (TAB) circuit  120 . At  121 , another portion  121  is adhered to surface  122 . Electrically, the TAB circuit  120  supports a plurality of input/output (I/O) connectors  124  for connecting an actuator chip  125 , also known as a heater chip, to the handheld printer during use. Pluralities of electrical conductors  126  exist on the TAB circuit to connect and short the I/O connectors  124  to the input terminals (bond pads  128 ) of the actuator chip  125  and skilled artisans know various techniques for facilitating this. In an exemplary embodiment, the TAB circuit is a polyimide material and the electrical conductors and connectors are copper or aluminum-copper. For simplicity,  FIG. 2  shows eight I/O connectors  124 , electrical conductors  126  and bond pads  128  but present day printheads have larger quantities and any number is equally embraced herein. Also, skilled artisans will appreciate that the number of connectors, conductors and bond pads, while shown as equal to one another, may vary unequally in actual embodiments. 
         [0023]    At  132 , the actuator chip  125  contains at least one ink via that fluidly connects to the ink of the compartment  116 . During printhead manufacturing, the actuator chip  125  is attached to the housing with any of a variety of adhesives, epoxies, etc., as is well known in the art. To eject ink, the actuator chip contains columns (column A-column D) of fluid firing actuators, such as thermal heaters. In other actuator chips, the fluid firing actuators embody piezoelectric elements, MEMs devices, and the like. In either, this crowded figure simplifies the actuators as four columns of six dots or darkened circles but in practice the actuators might number several dozen, hundred or thousand. Also, vertically adjacent ones of the actuators may or may not have a literal spacing gap or stagger there between. In general, however, the actuators have vertical pitch spacing, such as about 1/300 th , 1/600 th , 1/200 th , or 1/2400 th  of an inch along the longitudinal extent of a via. Further, the individual actuators are typically formed as a series of thin film layers made via growth, deposition, masking, patterning, photolithography and/or etching or other processing steps on a substrate, such as silicon. A nozzle member with pluralities of nozzle holes, not shown, is adhered to or fabricated as another thin film layer on the actuator chip such that the nozzle holes generally align with and are positioned above the actuators to eject ink. 
         [0024]    With reference to  FIG. 3 , a greatly exaggerated view of the handheld primer  10  shows a position sensor  20  and a controller  21 . The position sensor, preferably of the optical type, includes a transmitter  24  and a receiver  26  that together shine light  28  and capture reflections  30  from the media  16 . In this manner, the position or location of the housing, especially printhead  110  is made known at the controller regardless of random or predictable movement of the housing  14  by an operator. 
         [0025]    Among other things, the controller  22  also includes a stored to-be-printed representation of an image  32 . In turn, it correlates the position of the printhead, especially individual actuators, to the image. It then prints the image with ink  35  on the media  16  according to the image pattern  36  in the pixels  38 . A has-been-printed image  34  may also be stored or accessed by the controller to keep track of future printing and to determine whether the image has been printed completely or not. In structure, the controller embodies an ASIC, discrete IC chips, firmware, software, a microprocessor, combinations thereof or the like. Alternatively, the to-be-printed image  32  is dynamically updated to remove pixels that have been printed so that the has-been, printed information  34  is merged with the to-be-printed information. In either, the controller further includes a memory stored reference indicia  39  for comparison, in some instances, to the reference indicia of the media to reacquire a lost printer position or validate other than lost positions. 
         [0026]    With reference to  FIG. 4 , a handheld, printer  10  is being maneuvered over a media  16  in the direction of the arrow A to print an image  18  (representatively given as a Synchronous DRAM specification sheet). Near the image, as practicably as possible, is a reference indicia  11  in the form of an icon  99 . In a variety of ways, the reference indicia is provided on the media. In the first, it is provided by printing from the handheld printer  10 , such as before printing the image  18 . In the second, it is provided as a pre-printed media sheet. In the third, it is provided as a simply item for applying to the media. In may even occur as the result of a combination of the foregoing. As provided below with reference to other figures, the details of the pre-printed media and the supply item will be furnished. 
         [0027]    Regardless of how obtained, the inset shows a magnified representative of the reference indicia including both a location pattern  40  and a guide pattern  41 . As is seen, the location pattern is generally central to the reference indicia periphery  43  while the guide pattern  41  surrounds the location pattern. The guide pattern also includes indicators  45 , such as arcs or chevrons, which are used in combination with the optical sensor(s)  20  to direct the printer, especially sensors, over at least a portion of the location pattern. In this manner, once the sensor can observe the location pattern and communicate same with the controller  22 , including comparison to the stored reference indicia ( FIG. 3 ), the printer location can be reacquired after being lost, far example, during a print job. Normal printing occurs by returning the printer to the unfinished portion of the to-be-printed image. 
         [0028]    With reference to  FIG. 5 , a method for printing with a handheld printer utilizing reference indicia is given as  200 . At step  202 , the reference indicia is provided on the media. As before, this can occur via printing with the printer, application of a supply item to the media, or by way of a pre-printed media. At step  204 , the printing of the image begins. Naturally, this includes a user maneuvering the printer over the media and a controller correlating the image to fluid firing actuators for operation. Such is also done via the assistance of the inputs from the sensors, especially in ascertaining printer velocity or speed and ongoing changes in x and y positions of the printhead relative to the media and observing angular orientations (θ). Thereafter, determinations (regular, ongoing, continuous, irregular, random, etc.) are made at step  206  regarding the printer location relative to the image. If the printer location is known, printing of the image continues at step  208  until the image is fully printed. 
         [0029]    If the printer location is unknown, or lost, a reacquisition mode of printing is entered at step  210 . In this regard, it is preferred that printing of the image ceases so that poor print quality will not result. Then, at step  212 , directions to the reference indicia are indicated. In this regard, the position indicators  17  ( FIG. 1 ) are displayed to show the way to the reference indicia. Intuitively, if a reference indicia is printed on the media before printing of the image, for example, it is preferred that the indicia be so small as to avoid visual detraction from the image. Thus, it should be appreciated that the reference indicia may be so small that users do not even know of its existence and need directions to its location. In some instances, the area of reference indicia is contemplated on the order of a few mm 2 . 
         [0030]    Next, users follow the position indicators until the printer is eventually positioned over the reference indicia, step  214 . Automatically, the controller will then observe the reference indicia, especially the location pattern, and reacquire the location of the printer. Normal printing of the image then occurs by moving the printer back to a position on the media repairing printing, step  208 . Eventually, the complete image is fully printed. 
         [0031]    With reference to  FIG. 6 , reference indicia can be further used according to process  300 . That is, a reference indicia is provided on the media and printing of the image begins at steps  202  and  204 , as before. At step  306 , however, the printer is passed or traversed over the reference indicia during normal printing operations and the location of the printer relative to the image is updated or validated at step  308 . In this regard, reference indicia can be positioned on the media in known locations near the image such that users can regularly pass the printer over the indicia without stopping printing jobs and the current location of the printer be updated if slightly off (e.g., recalibrated) or validated if accurate. 
         [0032]    For example,  FIG. 7A  shows a media  16  for printing an image with reference indicia  11  along a length dimension. The reference indicia includes a plurality of related marks  97 , in this case tick marks, of substantially equal size, shape and spacing S. During use, when an operator prints an image  18  (dashed line) they can regularly traverse over the reference indicia to update or validate printer position. For instance, as the printer travels during image printing, it keeps track of the printer location relative to the image. Then, upon passing over any given mark  97 , the controller expects to see a mark in the nearby vicinity. Upon seeing a mark, it can then update its position if off, or validate its position if accurate. In either, fine-tuning of positional information is obtained. 
         [0033]    Also,  FIG. 7A  shows another feature of the invention in the form of a supply item  100  for use with the media  16 . In this regard, a substrate  103  ( FIG. 8 ) with a reference indicia  101  embossed, printed, engraved, etc., overlays a surface  107  of the media  16 . Preferably, it removably overlays the substrate so that, upon completion of printing the image, the substrate  103  can be removed. In various embodiments, the substrate is single- or multi-layered including an adhesive  105  for permanently or semi-permanently attaching to the substrate. For semi-permanent attachment a weak adhesive is contemplated white permanent attachment contemplates strong adhesives. In either, the composition of the substrate includes of a variety of materials including paper, plastic, metal, and combinations. Packaging of the items can also occur as one or more lengthy strips, such as seen in  FIG. 7A , or as a roll with perforated sections for tearing strips apart. Of course, other embodiments are possible. 
         [0034]    Alternatively,  FIG. 7B  shows a reference indicia  11  on a media  16  for use in handheld printing with both multiple related marks  97  and an icon  99 , of the type described in  FIG. 4  with both guide and location patterns thereon. In this manner, both absolute and relative printer positions are learned from the reference indicia. The absolute printer position occurs (similar to the example of  FIG. 4 ) with a guide pattern pointing toward a location pattern that the printer passes over to locate the starting point of printing and for reacquiring position if lost. The relative printer position occurs by regularly passing the printer over the marks  97  during a print job and this helps maintain calibration of the printer. 
         [0035]    In still other alternate embodiments,  FIG. 7E  shows the supply item  100  simply as the reference indicia  11  in the exclusive form of the icon  99 . For packaging, this too may be in a roll form or as a plurality of stamp-like substrates. In  FIGS. 7C and 7D , no longer is the reference indicia  11  provided as a supply item, but simply adorned on the media  16 . It is contemplated that the reference indicia  11  (as a singular embodiment of related marks  97  or as an icon  99 , or as a combination of both) will be printed on the media, but alternatively may be embossed, etched, engraved, deposited, or the like. In  FIG. 7F , the notion of more than one reference indicia is given as reference indicia  11  on both long sides of the media  16 . It is also shown in this embodiment that the reference indicia can be a composite indicia with both marks  91  and an icon  99 . Of course, it can further be one or the other. In  FIG. 7G , the notion that the reference indicia  11  for use with handheld printing can appear anywhere on the media  16  is given. As seen, a reference indicia  11  appears on a single, short side of the media. Naturally, skilled artisans can contemplate other embodiments and combinations of the foregoing are especially embraced herein. 
         [0036]    In any embodiment, certain advantages of the invention over the prior art are readily apparent. For example, the invention at hand provides updating/validating printer positioning during printing or reacquiring positioning, if lost, to complete an interrupted print job. Alternatively, the invention contemplates supply items for application to media or pre-adorned media with reference indicia for use with handheld printing. Less intuitively, use of reference indicia during handheld printing minimizes accumulated position errors. Better print quality then results. Also, because simple reference indicia can assist in printing, robustness is added and manufacturing costs are minimized. 
         [0037]    Finally, one of ordinary skill in the art will recognize that additional embodiments are also possible without departing from the teachings of the present invention. This detailed description, and particularly the specific details of the exemplary embodiments disclosed herein, is given primarily for clarity of understanding, and no unnecessary limitations are to be imported, for modifications will become obvious to those skilled in the art upon reading this disclosure and may be made without departing from the spirit or scope of the invention. Relatively apparent modifications, of course, include combining the various features of one or more figures with the features of one or more of other figures.