Media processing devices for applying printable conductive elements

A media processing device includes: a media processing head; a ribbon transport assembly configured to transport ribbon along a ribbon path between a ribbon dispenser and the media processing head; a graphite applicator disposed along the ribbon path, the graphite applicator configured to apply a combination of graphite and graphene to an active side of the ribbon via frictional engagement with the ribbon; and a media transport assembly configured to transport media from a media supply to the media processing head for transfer of at least a portion of the combination of graphite and graphene from the active side of the ribbon onto the media via application of at least one of heat and pressure at the media processing head.

BACKGROUND

Conductive elements may be affixed to various surfaces, such as temperature and other sensors, memories storing identifiers or other data, or the like. Producing such conductive elements, however, may be costly and/or time consuming, reducing the value of deploying such elements.

DETAILED DESCRIPTION

Deploying conductive elements as sensors, or portions of sensor circuits, may be desirable in a wide variety of contexts. For example, temperature and/or humidity sensors may be deployed on items such as packages to track cold-chain compliance, in medical settings such as on skin bandages, and the like. Applying such sensors (or components thereof) to surfaces such as packages, bandages, skin, or the like may be rendered less costly and time-consuming if the sensors or conductive elements thereof can be printed onto media such as a label or other substrate, rather than being previously manufactured, shipped and stored.

Deploying printable conductive elements, however, may require materials that are costly and/or time consuming to manufacture or otherwise prepare. For example, printable conductive elements may be deployed using a media processing device such as a thermal printer, equipped with media (e.g. labels or the like), and ribbon carrying a conductive material instead of, or in addition to, a pigment (e.g. ink). An example of such a conductive material is one or more layers of graphene or graphene oxide, a lattice of carbon with a thickness of one atom. Providing ribbon with a graphene coating may allow the media processing device to apply the graphene to the media in any of a wide variety of configurations, in a manner similar to the application of ink or other pigment to the media. Manufacturing graphene, however, is a costly and time-consuming process, which renders the use of graphene-coated ribbon for printing arbitrary conductive elements less appealing, and in some cases economically impractical. The discussion below sets out mechanisms for deploying lower-cost printable conductive elements.

Examples disclosed herein are directed to a media processing device, comprising: a media processing head; a ribbon transport assembly configured to transport ribbon along a ribbon path between a ribbon dispenser and the media processing head; a graphite applicator disposed along the ribbon path, the graphite applicator configured to apply a combination of graphite and graphene to an active side of the ribbon via frictional engagement with the ribbon; and a media transport assembly configured to transport media from a media supply to the media processing head for transfer of at least a portion of the combination of graphite and graphene from the active side of the ribbon onto the media via application of at least one of heat and pressure at the media processing head.

Additional examples disclosed herein are directed to a media processing device, comprising: a media processing head; a supply of ribbon having an active side, at least a portion of the ribbon having a combination of graphite and graphene releasable from the active side, the ribbon dispensable from the supply along a ribbon path towards the media processing head; a media transport assembly configured to transport media from a media dispenser to the media processing head, for transfer of a portion of the combination of graphite and graphene from the active side of the ribbon onto the media.

Further examples disclosed herein are directed to a method in a media processing device, the method comprising: controlling a ribbon transport assembly to transport a ribbon along a ribbon path from a ribbon dispenser toward a media processing head; at a graphite applicator between the ribbon dispenser and the media processing head, applying a combination of graphite and graphene to an active side of the ribbon via frictional engagement with the ribbon; controlling a media transport assembly to transport media from a media supply to the media processing head; and controlling the media processing head to transfer at least a portion of the combination of graphite and graphene from the active side of the ribbon to the media.

FIG.1illustrates a media processing device100, such as a thermal transfer printer. The device100includes a housing104supporting various other components of the device100, including a control panel108and various internal components to be discussed below. The internal components of the device100may be accessed via a door or cover112, which in this example is movably coupled to the housing104via hinges116. In general, the internal components mentioned above enable the device100to apply indicia, including indicia forming conductive elements, to media such as labels or the like, which is then output from the device100at an outlet120.

FIG.2illustrates the device100with the cover112(shown only partially) in an open position to expose certain internal components of the device100. In particular, the device100, as mentioned above, is a thermal transfer printer, in which pigment and/or conductive material is transferred from a ribbon to media such as a label, paper, or the like. The media, following removal from the device100at the outlet120, can then be affixed to a surface, or otherwise applied to the surface to transfer the pigment and/or conductive material to that surface. For example, the media can be applied to skin, to transfer conductive elements printed on the media from the media to the skin. In further examples, the media can include a wrist band, and the pigment and/or conductive material can be applied to an inner surface of the wrist band, to lie against the skin when the wrist band is worn. In such an implementation, the conductive material on the wrist band can form a sensor for use in medical settings, e.g. for identification and/or collecting physical measurements from a patient.

To transfer the pigment and/or conductive material from the ribbon to the media, the device100includes a media processing head, such as a thermal print head200, as well as a ribbon dispenser204and a media dispenser208. The ribbon dispenser204is a spindle206rotatably supported by the housing104in this example, and can support a spool of ribbon. The ribbon (not shown inFIG.2) carries, on an active side thereof, the pigment and/or conductive material, and is dispensed from the dispenser204towards the print head200, via a ribbon transport assembly that can include rollers and/or guide surfaces defining a ribbon path between the dispenser204and the print head200. The ribbon transport assembly includes, in this example, a guide roller212.

The media dispenser208, in this example, is a spindle rotatably supported by the housing104, to support a roll of media such as labels or the like (not shown inFIG.2). The device100also includes a media transport assembly, which includes a suitable set of guide surfaces and/or rollers for guiding media from the dispenser208towards the print head200. In this example, the media transport assembly includes a media dancer216.

The transport assemblies mentioned above enable the transport of both ribbon and media from their respective supplies to the print head200, which forms a nip with a platen roller220. The nip brings the ribbon and the media into contact between the print head200and the platen roller220. The print head200includes an addressable array of thermal elements that can be independently enabled or disabled by a controller of the device100. For example, the array may disposed in a line across the media's travel path through the nip, such that controlling the array as the media traverses the print head200results in the application of heat to specific portions of rows extending across the ribbon as the ribbon and the media travel together through the nip. The application of heat to the ribbon by the print head200causes the pigment and/or conductive material at positions corresponding to the activated thermal elements to release from the ribbon and affix to the media. In other examples, the media processing head need not be an addressable print head as described above, but can instead be a thermal transfer roller, e.g. a single thermal element rather than multiple individually controlled elements.

The ribbon loaded into the device100prior to operation thereof may be manufactured with a layer of conductive material, such as graphene or graphene oxide. As will be apparent from the discussion below, the layer of conductive material can include a combination of graphene and graphite (e.g. a layer of graphene, overlaid with graphite). Although graphene is preferred to graphite in the context of printable conductive elements, the combination mentioned above may be implemented at a substantially lower cost and complexity relative to ribbon coated exclusively with high-purity graphene. In other examples, as discussed below, the ribbon supported on the ribbon dispenser204may not include the conductive material, and the device100itself can include additional components to apply the conductive material to the ribbon prior to processing of the ribbon and the media at the print head200.

Turning toFIG.3, a side view of the device100with the cover112removed is illustrated. In addition to the components mentioned above, a ribbon path300is illustrated, along which the ribbon travels from a ribbon supply304(e.g. a spool mounted on the dispenser204), to the print head200, before being collected by a take-up roller308. A media path312is also illustrated, along which the media travels from a media supply316(e.g. a spool mounted on the dispenser208) to the print head200and out the outlet120. The device100also includes an applicator320disposed along the ribbon path300. The applicator320is configured to apply a layer of conductive material to an active side of the ribbon. The active side is the side of the ribbon facing towards the media, and which will therefore be in contact with the media at the nip formed by the print head200and the platen roller220. In the example ofFIG.3, the active side is the underside of the ribbon (i.e. the side facing the bottom of the drawing).

The applicator320can be a block of the constituent material forming the conductive material to be applied to the ribbon. In this example, therefore, the applicator320is a block of graphite, e.g. a cylindrical block over which the ribbon travels toward the print head200. The applicator320can be an idle (i.e. non-driven) roller, or a static block that the ribbon rubs against as the ribbon passes towards the print head200. For example, the applicator320can be fabricated as a block of graphite with a hardness equivalent to that of a 9B crayon. In some examples, the applicator320can be adapted from the core of a 9B crayon. Graphite softer than 9B can also be employed. In some examples, graphite harder than 9B may also be employed, however the applicator320preferably has a hardness no greater than that of a 2B crayon.

The applicator320can also include, in some examples, a leveling component at or downstream of the above-mentioned block of graphite, such as a doctor blade, a slot through which the ribbon travels towards the print head200, or the like. The leveling component can scrape or otherwise remove material transferred from the block of graphite to the ribbon that exceeds a predetermined height, in order to produce a coating of graphite and graphene on the ribbon with a substantially uniform thickness.

As will be apparent to those skilled in the art, rubbing graphite against a surface, such as the active side of the ribbon, deposits both graphite and graphene on the surface. Implementing the applicator320in the device100enables the use of standard, readily available ribbon without complex and costly manufacturing techniques to deposit graphene thereon, at the cost of obtaining graphene contaminated to a degree with graphite. It has been found that despite such contamination, the resulting indicia applied to the media exhibit conductivity and temperature sensitivity indicative of the presence of graphene on the media in sufficient quantity to act as a sensor, or a portion of a sensor circuit.

As seen inFIG.3, the applicator320is adjacent to the print head200. That is, the applicator320is at least closer to the print head200than to the ribbon supply304. Such a placement of the applicator320may reduce the distance travelled by ribbon that has been coated with graphene and graphite. As will be apparent, the graphite may shed from the ribbon as dust, which may accumulate in the device100, and reducing the distance travelled by coated ribbon may therefore reduce the frequency with which the interior of the device100requires cleaning.

Turning toFIG.4, another example is shown in which the applicator320is located adjacent to the ribbon supply304, rather than to the print head200. In such examples, the coated ribbon may travel further between the applicator320and the print head200and therefore may shed a greater amount of dust before the print head200. However, in such examples the applicator320may also be deployed in a removable ribbon cartridge. That is, the housing104of the device100can be configured to removably receive a cartridge housing supporting the dispenser204, the take-up roller308, the guide roller212, and the applicator320. When the ribbon is exhausted from the supply304, and/or when the applicator320has worn sufficiently to require replacement, the cartridge may be removed and replaced. In other examples, the applicator320alone may be replaced independently of the ribbon and/or the above-mentioned cartridge.

Turning toFIG.5, application of the conductive material to the ribbon is shown in greater detail. In particular, a ribbon500is shown travelling past the applicator320in a direction504, e.g. along the ribbon path300toward the print head200. A portion of the ribbon500, prior to contacting the applicator320, includes a substrate508(e.g. a plastic or other suitable base material for the ribbon500). The substrate can also include a thermally-activated release coating512defining the active side of the ribbon500. As the ribbon traverses the applicator320, a portion of the applicator320is transferred via friction onto the active side of the ribbon500, forming a layer516of conductive material, which in the current example includes graphene and graphite. The thickness of the coating516of conductive material may be, for example, from about 100 nanometers to about 5 microns.

As shown in the detail view520, the ribbon500may be provided with additional features to aid the conductive material from the applicator320in adhering to the ribbon500. In particular, the coating512and/or the substrate508itself can include a surface treatment514, such as a texture or increased roughness relative to the non-active side of the ribbon500, to improve adherence of the conductive material. In other examples, e.g. in which the ribbon500is manufactured with a coating of conductive material rather than having the coating516applied within the device100, the ribbon500may also include a protective coating overlaid on the conductive material, to mitigate the above-mentioned shedding of dust within the device100.

The media used in the device100may also include a surface treatment514, in some examples, such as a texture or area of increased roughness, to improve adherence of the conductive material to the media upon transfer at the print head200.

Variations to the above are contemplated. For example, in some embodiments the device100can include two or more applicators disposed at different points along the ribbon path300.