Abstract: A method and apparatus for adjusting a printhead. The position of a thermal printhead for printing on a print medium that passes between the printhead and a print medium support member can be adjusted relative to the print medium support member. The adjustment is accomplished by adjusting the position of a shaft, attached to a printhead heat sink and passing through a printhead support member, relative to the printhead support member. The adjustment mechanism, placed at the end of the shaft passing through the printhead support member, includes a lever that can be adjusted rotationally with respect to the axis of the shaft. In one embodiment, the lever has a series of wedging surfaces of differing longitudinal thickness which engage a fastener near the end of the shaft.

Abstract: A method of printing on a print face of a linerless media with the printing face of a printhead without a platen member opposite the printing face. The method comprises the steps of, guiding the print face of the media to a point close adjacent and slightly above the printing face; routing the print face across the printing face; pulling the media across the printing face from a point slightly above the printing face; and, creating a drag force on the media to hold the print face against the printing face during printing. A guide member guides the media to a point close adjacent the printing face. The drag can be created by putting a drag clutch on the supply roll, routing the media between drag rollers, or having a high friction surface on the guide member.

Abstract: An optical element causes emission of a visible spotter beam [emitted by]from a hand-held scanning bar code reader. The visible beam provides visible indications of the area of a surface which is being scanned by an invisible scanning beam. The optical element transforms the visible spotter beam, at its extreme of travel, into two pairs of cursor beams which are directed along predetermined trajectories relative to the trajectory followed by the scanning beam. The predetermined trajectories can be above and below, or to the left and right of the center of travel of the invisible scanning beam. In one embodiment, a method of identifying the proper focusing distance of the scanning reader is presented. The method identifies the focusing distance by directing the pairs of cursor beams formed from the visible beam at its two angular extremes to form a predetermined pattern indicating the proper focusing distance.

Abstract: A method and apparatus for controlling a thermal printhead. In response to a sequence of print commands, the method and apparatus generate an energization signal for each thermal print element in the printhead. In one embodiment, the energization is a function of at least the present print command and a future print command. In certain embodiments, the energization signal may also be a function of a past print command, print commands for at least one adjoining print element, and other parameters. Each print element in the printhead can, accordingly, be maintained at a proper temperature to ensure long printhead life and cause the printhead to generate sharp images.

Abstract: A thermal printhead formed on a substrate. The plurality of thermal print elements in the thermal printhead are formed in a linear array. Each of the plurality of thermal print elements is respectively connected to a plurality of common electrode traces and a plurality of ground electrode traces. The common electrode traces are switchably connected to a single common electrode and the ground electrode traces are connected to a single ground electrode. The common electrode is held at a common voltage and the ground electrode is held at a ground voltage. The electrical circuit includes at least one common remote sense electrode connected to the single common electrode and, optionally, at least one ground remote sense electrode connected to the single ground electrode.

Abstract: A system for controlling the temperature of the printing elements of a thermal printhead. The printhead is provided with a plurality of spaced apart temperature sensor that measure the temperature at various locations on the printhead. A processor receiving outputs from the sensors determines the approximate temperature of each printing element based upon its proximity to at least one temperature sensor and the temperature sensor outputs. The processor then uses the approximate temperature of the printing elements to formulate either a strobe signal or a serial data stream that is applied to the respective printing element. Each printing element thus receives a quantity of energy that is a function of whether the printing element will contribute to the printing of an image during a scan line as well as the approximate temperature of the printing element.

Abstract: A bar code symbology employs symbol characters that are 13 modules wide and employs 4 bars, all of the bars being 1-wide bars. Three of the symbol characters are used as a stop character, a start character and a numeric compression start character. The start/stop characters have a particular bar/space pattern to allow standard bar code readers to determine the state of optical focus of an electro-optical input device in the reader. The numeric compression start character, and a numeric compression latch character, initiate a numeric compression method that allows three symbol characters to encode five numeric data characters. Shift and latch symbol characters allow the full ASCII and extended ASCII characters to be encoded under the symbology of the present invention. The symbology employs a single error detection character generated by a prime modulo 53 method.

Abstract: A method and apparatus for maintaining a constant optical path length when scanning objects at different distances. The apparatus has a reading device that reads data carrying symbology on an object being scanned, and an optical system having a plurality of optical paths between the object being scanned and the reading device, where each of the plurality of optical paths has a different path length. The apparatus also has a size detector that determines a dimension of the size of the object being scanned and outputs a signal based on the dimension, and a selecting device that selects one of the plurality of optical paths of the optical system based on the signal output by the size detector to maintain an optical path length between the object being scanned and the reading device within a predetermined range.

Abstract: In a label printer printing on individual labels carried in spaced relationship on a surface of a longitudinally moving backing strip, this invention discloses apparatus for adjustably sensing leading edge positions of the labels. A stationary member is carried above the backing strip on one side of the backing strip. A movable member is carried by the stationary member for longitudinal movement along the path of the backing strip. There is provision for adjusting the longitudinal position of the moving member. A sensor is carried by the movable member for sensing leading edge positions of individual labels as a function of a change of thickness between the backing strip alone and the backing strip with a label on the surface. Both optical and mechanical versions are disclosed.

Abstract: A method and apparatus for transmitting data in a packet radio communication system having data sources, destinations and intermediate repeaters. According to a packet protocol, a repeat count in the protocol is decremented each time a packet is retransmitted, until the repeat count reaches zero, at which time the packet is discarded. According to another packet protocol, a sequence index is used to prevent duplicate packets from being received by requiring that the sequence number fall within a sequence number window at each device, which is incremented each time a packet is received. The sequence number is also used to cause the retransmission of packets which are lost, at which time the sequence number windows in the devices which are affected are reset to allow transmission of the lost packet.

Abstract: A method and window for providing a clean aperture at the reading face of a symbology reader. The window includes a layered structure including laminar sheets of optically transmissive material overlaying a window base and the adjacent laminar sheets. Each laminar sheet is releasably bonded to the window base. In use, when the outermost laminar sheet is damaged, it is peeled away to reveal the clean sheet beneath. In one embodiment, each laminar sheet includes an integral grasping tab projecting outwardly. The grasping tabs in each successive sheet are offset to permit a user to grasp the single tab corresponding to the outermost laminar sheet to peel it away. In one embodiment, a flexible boot covers an edge portion of the window to protect the window structure and retain the laminar sheets from being inadvertently peeled off. In one embodiment, the grasping tabs are replaced with recesses to provide access for gripping subsequent sheets.

Abstract: A bar code scanner-and-reader system wherein a scanner unit scans the encoded information contained in a selected bar code and transmits the information to a reader unit that displays the decoded information in human or machine readable form where the system has an information transfer link between the scanner and reader units that is a line-of-sight (LOS) infrared (IR) wireless link.

Abstract: A spur gear ratchet mechanism is provided to enable simplified replacement of a ribbon roll for a thermal transfer printer. The spur gear ratchet mechanism is intended for use with a printer comprising a fixed base portion and a pivotal cage portion in which the cage portion can be selectively moved between a closed operational position and an open non-operational position. A transporting mechanism controls the movement of the thermal transfer ribbon, and is attached to the pivotal cage portion so that it moves in association therewith. The transporting mechanism comprises at least one rotatable hub that is driven by an associated drive gear. When the cage portion moves from the closed operational position to the open non-operational position, the drive gear disengages from the pinion of a drive motor that is fixed within the base portion of the printer. Concurrently, the spur gear ratchet mechanism engages the drive gear and impedes undesirable rotation of the hub.

Abstract: A handle assembly for a portable electronic device includes a handle attached to the electronic device and a trigger projecting from the handle. A replaceable trigger switch is selectively, mechanically retained by the handle, allowing simple replacement of the switch. In a first embodiment, the switch is located within a rechargeable battery pack, and the battery pack is removably retained within the handle. In a second embodiment, the replaceable trigger switch is retained within a trigger frame, and the trigger frame is removably retained within the handle.

Abstract: A symbology reader having a pair of optical sources for producing cursor beams. The cursor beams are emitted from two spaced apart locations on the reader and angled with respect to an image direction of a detector assembly within the reader. The cursor beams intersect at a desired object distance to form a composite image indicating that the reader is positioned an appropriate distance from a target object. In one embodiment, multiple composite images are formed. The composite images are spaced apart to delineate the extent of an object field of the detector assembly. In one embodiment, the optical sources are LEDs concealed beneath a mounting platform and emitting light transversely to the image direction. In this embodiment, turning mirrors redirect the light forward of the reader to form the cursor beams.

Abstract: An apparatus for use in a thermal printer for printing bar code symbols onto a paper substrate material is provided which utilizes a ribbon having a multi-transfer ink layer. The thermal printer enables the ink ribbon to be transported at a rate that is selectively lower than the transporting rate of the paper substrate. The thermal printer comprises a platen and a thermal head disposed adjacent to the platen having a region defined therebetween through which the paper substrate material is transported at a first rate. Images or symbols are imprinted onto the paper substrate material by operation of the thermal head in cooperation with ink from the multi-transfer ink ribbon advanced to the region. A supply hub carries a supply of the ribbon, and a first motor is mechanically linked to the supply hub. The first motor rotates the hub in a direction opposite to a direction of advancement of the ribbon.

Abstract: An electrophotographic printer especially for bar code printing having an image transfer drum for placing an image onto a continuous form to be printed moved along a path by a form feed. A fusing roller is located downstream to fix the image on the form. The form is fed along a path past the transfer drum and fusing roller and after printing the last printed form is separated from the continuous form downstream of the image transfer drum leaving a leading edge on the unprinted form. The separation of the printed form is signaled to a controller which disables the image transfer device and fusing roller and causes the form feed to reverse moving the new leading edge upstream to a location immediately adjacent the image transfer drum. Various forms of printing, fixing the image onto the form, feeding the form and various types of forms such as barcoded labels on a carrier continuous form are disclosed.

Abstract: A portable bar code reader including a keyboard and a bar code system computer wherein the bar code system computer is constructed for executing a standard operating system to enable the bar code system computer to execute standard application programs written for the standard operating system. The keyboard includes a keypad coupled to a keyboard processor and a keyboard memory wherein the keyboard memory is constructed to store a plurality of token data units. The keypad includes a plurality of keys and is constructed to provide a plurality of X-Y position signals wherein each X-Y position signal is indicative of an associated key being depressed. The keypad also includes a change meaning assembly constructed to provide a change meaning signal to the keyboard processor 308. The keyboard processor 308 is responsive to the change meaning signal to select a portion of the keyboard memory that stores the meanings of the keys associated with the change meaning signal.

Abstract: A symbology reader having a replaceable window element. The window element is user replaceable and incorporates varying features for varying applications. By removing and replacing a window element, the user may provide a clear, uncontaminated surface through which light may enter or exit the reader. In some embodiments, the window element includes focusing elements for defining a target plane for a detector assembly within the reader. In one such embodiment, the reader also includes additional focusing elements for focusing spotter beams to aid a user in aligning the reader to the defined target plane. The window element also incorporates polarizers and color selected filters for optimizing the reader for specific applications. In one embodiment, the reader includes a protective rubber boot to provide shock protection and to releasably retain the window element in attachment to the reader. In an alternative embodiment, the reader includes a releasable tab to hold the window element in position on the reader.

Abstract: A method and apparatus for estimating an X-dimension of a machine-readable symbol having a recognition pattern that includes elements comprising bars and spaces. The method and apparatus proceed from a boundary between two of the elements of the machine-readable symbol. The method and apparatus selects a plurality of sampling paths across a particular one of the elements at the boundary, and determines a median path length across the particular one of the elements out of each of the plurality of sampling paths. The selection of a plurality of sampling paths and the determination of the median path length are repeated for each of the elements of the recognition pattern. The method and apparatus then averages the median path length for all the elements to provide the estimated X-dimension of the machine-readable symbol.