1. Field of the Invention
The present disclosure relates to printers in general and, more particularly, to a direct thermal barcode printer.
2. Description of the Related Art
The use of electronically controlled thermal printers has increased very rapidly over the last few years. In particular, the market for thermal label printers has shown significant improvement with users focusing on utilizing label printing, especially bar-code labeling, to improve capital asset management, inventory control or time and attendance reporting—or to meet corporate or industry mandated labeling requirements—such as automotive AIAG, electronic EIA, or retail UCC/UPC specifications. Label printers typically incorporate a media supply of “peel away” labels adhered to a coated substrate wound in a rolled configuration. The media with the labels is drawn against a printing head, which causes images to be created on the label in response to localized heating of the printing head.
In some prior art printers, calibration or alignment of the print head with respect to the different print media types is complicated and may require the printer to be returned to the factory or a service center. This may result in additional costs to the customer as well as increased “down-time” or availability of the printer. Therefore, a need exists for a printer that may be calibrated or aligned at the customer's location.
A direct thermal barcode printer is hereinafter disclosed. According to an embodiment of the disclosure, the direct thermal barcode printer includes a base, a platen bracket, and a cover releasably attached to the platen bracket. A printed circuit board is attached to the platen bracket and the combination is removably positioned in the base. A media storage assembly, a media guide assembly, and a carrier assembly are also removably attached to the platen bracket.
In particular, the media storage assembly is adapted to receive a quantity of a print media and position the print media for printing. The media storage assembly includes first and second support members that are positionable along an axis of the platen bracket and generally biased by springs towards a center of the platen bracket thereby securing the print media in the media storage assembly. First and second support members may lock in position after a desired amount of movement away from the center of the platen bracket thereby facilitating the installation and/or removal of the print media in the media storage assembly. Additionally, movement of the first and second support members may be synchronized such that when a support member is moved a distance from the center of the platen bracket, the other support member moves a corresponding distance in the opposing direction from the center of the platen bracket.
The media guide assembly includes first and second guide portions that are movable towards and away from each other to define a media path therebetween. Each guide portion includes first and second openings at opposed ends of the guide portion with a channel portion disposed between the first and second openings. As assembled, first and second openings of each guide portion define first and second openings of the media guide assembly. In addition, the first and second channel portions define a channel through the media guide assembly for receiving a quantity of the print media therethrough. One of the guide portions may include a sensor for detecting the presence or absence of the print media. Additionally, movement of the first and second guide members may be coordinated such that when a guide member is moved a distance from the center of the platen bracket, the other guide member moves a corresponding distance in the opposing direction from the center of the platen bracket. A roller is disposed near one of the openings of the media guide assembly for advancing or retracting a quantity of the print media.
A carrier assembly is positioned atop a portion of the platen bracket such that is proximal to the roller. The carrier assembly includes a carrier bracket having a pair of carrier latches. A print assembly, a print adjustment assembly, and a pressure adjustment assembly are attached to the carrier bracket. Carrier latches include torsion springs and fingers for biasing the carrier assembly towards the platen bracket during printing operations. The print assembly is most proximal to the roller and includes an adapter plate and a print head attached thereto. One or more print head cables may be connected to the print head for communicating data to and/or from the print head. The adapter plate includes first and second shaft brackets and a pivot bracket adapted to receive a shaft therethrough. In one embodiment, the pivot bracket has an open side.
The print adjustment assembly, in cooperation with the carrier bracket, includes a shaft and one or more thumbwheels rotatably attached to the carrier bracket. Rotation of one thumbwheel urges the shaft longitudinally within an elongate opening of the carrier bracket. As the shaft contacts a surface of either shaft bracket without contacting a surface of the pivot bracket, the adapter plate is pivoted causing it to skew with respect to the roller. In one embodiment, two thumbwheels are included that are independently rotatable for precisely aligning the print head to the print media and the roller. In another embodiment, the thumbwheels are adapted for engaging correspondingly dimensioned holes in the platen bracket for releasably positioning the carrier assembly in the platen bracket.
The print head is rotatably mounted to the carrier bracket allowing repositioning of the print head towards and away from the roller. The pressure adjustment assembly includes a hub and at least one compression spring disposed between the hub and the carrier bracket. A ridge disposed on an outer surface of the hub interacts with at least one pointer on the carrier bracket such that rotation of the hub compresses or decompresses the at least one compression spring such that the print head applies more or less pressure, respectively, to the print media, thereby adjusting the printing pressure.
Embodiments of the presently disclosed direct thermal barcode printer are described herein with reference to the drawings, wherein:
Embodiments of the presently disclosed direct thermal barcode printer will now be described in detail with reference to the drawings, in which like reference numerals designate identical or corresponding elements in each of the several views.
Referring initially to
Printed circuit board 20 is attached to a bottom portion of platen bracket 40 as seen in
Although only one latch 32 is shown in
Referring now to
Additionally, a plurality of feet 17 is disposed along a bottom surface of base 10 to minimize movement of printer 1 after it is placed in a desired location. A slot 14 is defined along a rear-facing surface near a bottom surface of base 10. Slot 14 is configured and dimensioned to receive interface connection 22 such that interface connection 22 is accessible from the exterior of the assembled printer 1.
Platen bracket 40 will now be described in detail with reference to
Media storage assembly 50 includes spaced apart first and second support members 51a, 51b each of which include a disc 52a, 52b that is adapted for engaging a portion of media supply 53. Media supply 53 may include a support tube 53a that engages discs 52a, 52b such that media supply 53 is rotatable on discs 52a, 52b thereby allowing print media to be fed from media supply 53. In another embodiment, first and second support members 51a, 51b also include additional discs 52c, 52d, respectively, that are configured and dimensioned for engaging a differently dimensioned media supply 53. By way of example only, discs 52a, 52b may be configured for rotatably receiving support tube 53a having a diameter of approximately 1 inch whereas discs 52c, 52d may be configured for rotatably receiving support tube 53a having a diameter of approximately 1.5 inches. In addition, mounting plates 54a, 54b, each having at least one foot 55, are attached to a bottom portion of support members 51a, 51b. Toothed members 56a, 56b are attached to respective mounting plates 54a, 54b and are generally elongate structures that are attached transverse to respective support members 51a, 51b. Support members 51a, 51b are positionable towards and away from each other as described in detail hereinbelow.
Media guide assembly 70 includes spaced apart first and second guide portions 71a, 71b that are also positionable towards and away from each and will be discussed in detail hereinafter. More specifically, guide portions 71a, 71b include channel portions 76a, 76b that are generally arcuately shaped. Channel portions 76a, 76b have respective first open portions 77a, 77b and respective second open portions 78a, 78b. When media guide assembly 70 is installed in platen bracket 40, first open portions 77a, 77b define a first open end 77, second open portions 78a, 78b define a second open end 78, and channel portions 76a, 76b define a channel 76 extending between open ends 77, 78. First and second open ends 77, 78 in conjunction with channel 76 define a media path. The spacing between first and second media guide portions 71a, 71b define a width of the media path. A first toothed member 72a and a second toothed member 72b are attached in a generally transverse arrangement to a bottom portion of guide portions 71a, 71b. In addition, each guide portion 71a, 71b includes at least one foot 74.
In one embodiment of printer 1, one or both of guide portions 71a, 71b include a sensor 75. Sensor 75 is adapted to detect the presence and/or absence of a print media in media guide assembly 70 and is in communication with control circuitry on printed circuit board 20. Sensor 75 may be an optical sensor, a mechanical sensor, or another suitable sensor as is known in the art. The presence or absence of print media, as determined by sensor 75, influences functions of printer 1 according to programming within the control circuitry. By way of example only, the absence of print media may inhibit operation of motor 46, provide audible or visible indication of the absence of print media, or inhibit printing operations.
Movement of first and second support members 51a, 51b will now be discussed with reference to
When positioned in platen bracket 40, first and second toothed members 56a, 56b are oriented towards each other and spaced apart to accommodate a gear 62 (
Referring again to
First and second support members 51a, 51b are installed in platen bracket 40 as follows. Each support member 51a, 51b is positioned near a wall of platen bracket 40 such that feet 55 are aligned with the enlarged end region of guide slots 33a–d and tabs 57a, 57b are aligned with the enlarged end regions of guide slots 33e–f. When first and second support members 51a, 51b are aligned, toothed members 56a, 56b are also aligned with respective holding arms 35a, 35b in holding slots 34a, 34b. Since feet 55 and tabs 57a, 57b are aligned with the enlarged end portions of their respective guide slots, as first and second support arms 51a, 51b are moved towards platen bracket 40, toothed members 56a, 56b are slidably received in holding slots 34a, 34b respectively. In addition, toothed members 56a, 56b deflect respective holding arms 35a, 35b in a generally downward direction as support arms 51a, 51b are moved in a generally downward direction.
After support members 51a, 51b are positioned in platen bracket 40, movement of support members 51a, 51b towards each other disengage toothed members 56a, 56b from a top surface of holding arms 35a, 35b thereby allowing the bias of holding arms 35a, 35b to return them into a substantially parallel alignment with their respective holding slots 34a, 34b. Extensions on feet 55 and tabs 57a, 57b slidably engage portions of the bottom surface of platen bracket 40 (see
As support arms 51a, 51b move towards outside walls of platen bracket 40, tabs 57a, 57b contact ends of holding arms 35a, 35b thereby inhibiting additional outward movement of support members 51a, 51b. In particular, holding arms 35a, 35b are configured such that when toothed members 56a, 56b contact the ends of holding arms 35a, 35b, feet 55 and tabs 57a, 57b are positioned inboard of the enlarged end portions of their respective guide slots, thereby preventing feet 55 and tabs 57a, 57b from aligning with the enlarged end portions of their respective guide slots to retain support members 51a, 51b in platen bracket 40.
Support members 51a, 51b may be removed from platen bracket 40 as follows. Prior to or concurrently with outward movement of support members 51a, 51b, holding arms 35a, 35b are urged generally downwards to overcome their normal bias, thereby repositioning them such that their ends will not engage toothed members 56a, 56b. Continued outward movement of support members 51a, 51b position toothed members 56a, 56b such that they slidingly contact the top surface of holding arms 35a, 35b. By positioning toothed members 56a, 56b on the top surface, the deflection of holding arms 35a, 35b is maintained and toothed members 56a, 56b may slide along and permit support members 51a, 51b to be moved outwards towards the walls of platen bracket 40. In particular, support members 51a, 51b are moved such that feet 55 and tabs 57a, 57b are aligned with the enlarged end portions of their respective guide slots, thereby allowing generally upward motion to remove support members 51a, 51b from platen bracket 40.
Additionally, platen bracket 40 includes guide slots 41a, 41b that are adapted for slidably receiving feet 74 of first and second guide portions 71a, 71b. Each guide slot 41a, 41b includes an enlarged portion adapted for receiving foot 74 in a manner such that each guide portion 71a, 71b may be installed or removed from platen bracket 40. With guide portions 71a, 71b disposed in platen bracket 40, respective toothed members 72a, 72b are oriented towards each other and spaced apart to accommodate a gear 64 (
As shown in
In one embodiment, media storage assembly 50 is adapted for locking support members 51a, 51b in an open position wherein a predetermined distance between support members 51a, 51b is maintained without additional user intervention as would be desirable prior to loading a quantity of print media 53. Referring to
Movement of second support member 51b towards the center of platen bracket 40 is inhibited by the engagement of edge A of second support member 51b and a vertical surface of ramp member 40b. As discussed hereinabove, support members 51a, 51b are configured to move substantially in unison. Since inwards movement of second support member 51b is inhibited by ramp member 40b, inwards movement of support member 51a is also inhibited, thereby locking media storage assembly 50 in the open position. By applying force to second support member 51b in a direction away from roller 49, the bottom surface of second support member 51b depresses second ramp member 40c, thereby allowing second support member to tilt away from roller 49 and disengaging edge A from the vertical surface of first ramp member 40b. With second support member 51b tilted away from roller 49 and edge A disengaged from first ramp member 40b, second support member 51b is no longer inhibited from movement towards the center of platen bracket 40 and media storage assembly 50 is now in the unlocked position. Support members 51a, 51b are now capable of movement towards the center of platen bracket 40 by the bias of springs 68 (see
Carrier assembly 80 is illustrated in
Carrier assembly 80 is maintained in proximity to platen bracket 40 using a pair of carrier latches 93 as shown in
Print assembly 110, as illustrated in
As seen in
Interspaced between adapter plate 120 and carrier bracket 82 is pressure adjustment assembly 130 as seen in
Referring now to FIGS. 7,7A, and 8, hub 131 has a ridge 134 along an outside surface thereof that includes a series of ramps defining a series of angles with respect to a bottom surface 135 of hub 131. Hub 131 is positionable among a plurality of positions including a first or minimum pressure position, a second or maximum pressure position, and at least one pressure position therebetween. In addition, hub 131 is disposed in throughhole 84 such that ridge 134 slidably engages posts 136. As hub 131 rotates among the plurality of positions, ridge 134 rides along posts 136. Since ridge 134 includes a series of ramps, as hub 131 rotates among the plurality of positions, hub 131 compresses or relaxes spring 132a. In the minimum pressure position, hub 131 is positioned such that spring 132a is in a relatively relaxed state, thereby applying a minimum amount of force to adapter plate 120 and print head 112 applies a minimum amount of pressure against print media 53. As hub 131 is rotated towards the maximum pressure position, movement of ridge 134 along posts 136 compresses spring 132a, thereby applying more force to adapter plate 120 and print head 112 applies an increasing amount of pressure against print media 53 that is proportional to the compression of spring 132a.
In addition to rotatable movement, adapter plate 120, and thus print head 112, is also capable of being pivoted about a central point using print adjustment assembly 90 as discussed herein. Print adjustment assembly 90 includes a shaft 91 and at least one thumbwheel 92. Shaft 91 is disposed through elongate holes 88 of carrier bracket 82. Elongate holes 88 and shaft 91 are configured and dimensioned such that shaft 91 is rotatable in elongate holes 88 and also positionable along a longitudinal axis thereof. Shaft 91 is slidably received in a groove 104 of the at least one thumbwheel 92. In one embodiment, the at least one thumbwheel 92 includes an aperture 97 for receiving screw 95. Aperture 97 is generally arcuate to correspond to the curvature of thumbwheel 92 and is located along a peripheral region of thumbwheel 92. In this configuration, the at least one thumbwheel 92 is eccentrically attached to shaft 91. In addition, the at least one thumbwheel 92 includes a central orifice 100 with a plurality of fingers 102 extending along an inner circumference thereof. Fingers 102 slidingly engage an inner surface of opening 86 such that the at least one thumbwheel 92 is rotatable in openings 86. The at least one thumbwheel 92 is attached to carrier bracket using screw 95 and washer 96.
The at least one thumbwheel 92 is rotatable and capable of positioning shaft 91. Shaft 91 is positioned such that it extends through shaft brackets 123a, 123b and pivot bracket 124. In one embodiment, shaft 91 does not contact inner surfaces of shaft brackets 123a, 123b or pivot bracket 124. Groove 104 of the at least one thumbwheel 92 engages an end of shaft 91 and the at least one thumbwheel 92 is attached to carrier bracket 82 using screws 95 and washers 96 thereby fastening shaft 91 to carrier assembly 80 and providing a rotating surface for adapter plate 120 for adjusting a distance between print head 112 and roller 49 as discussed above.
In an embodiment of carrier assembly 80, adapter plate 120, to which print head 112 is attached, is also pivotable about pivot bracket 124 in addition to being rotatable on shaft 91 along an axis thereof. Since shaft brackets 123a, 123b are enclosed structures, they maintain the relative position of shaft 91 to adapter plate 120 while allowing shaft 91 to rotate freely. However, pivot bracket 124 has at least one open side 127 thereby providing greater range of motion to shaft 91 in pivot bracket 124. By providing a greater range of motion to shaft 91, adapter plate 120, and ultimately print head 112, may be pivoted about pivot bracket 124 as detailed below.
In an embodiment having a pair of thumbwheels 92, each thumbwheel 92 is rotatably attached to carrier bracket 82 such that each thumbwheel 92 is capable of independent rotation. With screw 95 loosely contacting thumbwheel 92, rotation of thumbwheel 92 causes rotational forces to be transferred to shaft 91 through the engagement of an end of shaft 91 and groove 104 in thumbwheel 92. Since shaft 91 is axially offset from a center of thumbwheel 92, the resulting eccentric motion urges shaft 91 to move along the longitudinal axis of elongate hole 88. Once shaft 91 is moved into contact with the inner surface of one of shaft brackets 123a or 123b, continued longitudinal movement of shaft 91 urges adapter plate 120 to move a corresponding amount in a corresponding direction. While one thumbwheel 92 is rotating, the other thumbwheel 92 may be held stationary thereby acting as a pivot point for shaft 91 and adapter plate 120. In this configuration, the alignment between print head 112 and roller 49 may be altered to accommodate operating parameters of printer 1 (i.e. print head 112 is skewed in relation to roller 49). Additionally, both thumbwheels 92 may be rotated to alter the alignment between print head 112 and roller 49 in the manner described above. Alternatively, thumbwheels 92 may be operated substantially simultaneously to alter the alignment between print head 112 and roller 49. Independent rotation of thumbwheels 92 modifies the angular relationship between print head 112 and roller 49 while simultaneous rotation of thumbwheels 92 will modify the lateral relationship between print head 112 and roller 49. Once the desired alignment is attained, screws 95 may be tightened to minimize alteration of the desired alignment.
In addition, thumbwheels 92 are adapted for positioning and attaching carrier assembly 80 to platen bracket 40 wherein each thumbwheel is adapted to be received by an opening 40a (see
By providing print adjustment assembly 90, printer 1 may be field calibrated or aligned by an operator or field service personnel thereby reducing “down-time” or unavailability of the printer as well as reducing the operating and maintenance cost of the printer to the customer.
It will be understood that various modifications may be made to the embodiments disclosed herein. Therefore, the above description should not be construed as limiting, but merely as exemplifications of preferred embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.
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Number | Date | Country | |
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20060228148 A1 | Oct 2006 | US |