188宝金博页面版

EP 1 858 991 B12510152025303540455055DescriptionBACKGROUND[0001] Infrared (IR) sensors and associated infrared sensitive inks have traditionally been used for tracking and au-thenticating a number of different objects. More specifically, labels, barcodes, or other identifiable markings formed frominfrared sensitive inks have been formed on the surface of a number of objects. Once marked, objects could then beilluminated with IR light and examined by an infrared sensor to authenticate or track the object.[0002] While traditional methods for tracking and authenticating objects with infrared sensors and associated infraredsensitive inks have been used, these traditional methods have a number of limitations. Specifically, water-based inkscontaining water soluble IR sensitive dyes have durability and water fastness limitations. Similarly, solvent-based inkscontaining solvent soluble IR dyes have manufacturing and environmental limitations due to solvent emission. UV curableinks provide unique benefits of print durability as well as environmental friendliness by eliminating solvent emissions.However, many of the IR dyes tend to bleach or experience photo chemical degradation upon exposure to high intensityradiation used for curing UV curable inks.SUMMARY[0003] An ultraviolet (UV) curable ink having infrared (IR) sensitivity includes an ultraviolet (UV) light curable matrix,a UV photoinitiator, and an infrared sensitive dye.BRIEF DESCRIPTION OF THE DRAWINGS[0004] The accompanying drawings illustrate various embodiments of the present system and method and are a partof the specification. The illustrated embodiments are merely examples of the present system and method and do notlimit the scope thereof.Fig. 1 is a perspective view of an ink dispensing apparatus, according to one exemplary embodiment.Fig. 2 is a bar graph illustrating the maintenance of IR sensitivity after UV curing, according to one exemplaryembodiment.[0005] Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.DETAILED DESCRIPTION[0006] An exemplary formulation of UV curable inks containing IR dyes which retain their IR sensitivity (i.e. do notundergo photochemical degradation) even after exposure to high intensity radiation used for curing the ink is disclosedherein. More specifically, according to one exemplary embodiment, a UV curable ink containing IR dyes which retaintheir IR sensitivity includes a UV curable matrix, a UV photoinitiator, and an IR sensitive dye. According to this exemplaryembodiment, the IR dye may be any number of infrared sensitive or near infrared sensitive dyes.[0007] As used in the present specification and the appended claims, the term "ultraviolet curable ink" or "UV curableink" is meant to be understood broadly as referring to any formulation of ink including a component that is configured toharden and/or cure when exposed to ultraviolet radiation. Additionally, the term "infrared sensitive dye" or "IR sensitivedye" is meant to be understood broadly as a dye that absorbs light in the infrared light spectrum (light having a wavelengthfrom approximately 1 micron to 1 mm). Similarly, the term "near infrared sensitive dye" is meant to be understood asany dye that absorbs light having a wavelength ranging from approximately 0.7 microns to approximately 3 microns.[0008] In the following description, for purposes of explanation, numerous specific details are set forth in order toprovide a thorough understanding of the present system and method for a UV curable ink having IR sensitivity. It will beapparent, however, to one skilled in the art, that the present method may be practiced without these specific details.Reference in the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, orcharacteristic described in connection with the embodiment is included in at least one embodiment. The appearance ofthe phrase "in one embodiment" in various places in the specification are not necessarily all referring to the sameembodiment.[0009] Figure 1 illustrates the components of the present system that facilitate reception of the UV curable ink havingIR sensitivity (160) onto the ink receiving medium (170). As shown in Figure 1, a medium transport system (180) includinga number of positioning rollers and/or belts may transport and positionally secure an ink receiving medium (170) duringa printing operation. Alternatively, any number of belts, rollers, substrates, or other transport devices may be used totransport and/or positionally secure the ink receiving medium (170) during a printing operation, as is well known in the