Patent Application
20100120613
A label, method of printing and method of manufacture described herein relates generally to improvements to printable labels. More particularly, the invention relates to improvement to labels used in harsh environments.
A label used in a hazardous environment can come into contact with harsh chemicals, abrasive materials and other elements that will degrade the readability of the label. Labels uses in such hazardous conditions typically have a protective layer applied to the exterior surface of the label to protect the label from the hazardous environment. Currently, labels used in hazardous environments are printed using standard printing processes (i.e., thermal, ink jet or laser) and then in a separate step, they are laminated with a transparent layer to protect the labels from hazardous conditions. The lamination step, while effective, is time consuming and adds expense to the label.
The invention, in accordance with preferred and exemplary embodiments, together with further objects and advantages thereof, is more particularly described in the following description taken in conjunction with the accompanying drawings in which like reference characters designate the same or similar parts throughout the several views and wherein:
In the following description, numerous details are set forth to provide an understanding of the claimed invention. However, it will be understood by those skilled in the art that the claimed invention may be practiced without these details and that numerous variations or modifications from the described embodiments are possible.
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To print a pattern containing text, graphic or an image on the printable multilayer sheet 10, a section of the printable multilayer sheet 10 is feed through the thermal print head assembly 350. Based on the desired pattern, the print head 340 selectively generates heat in selected areas on the surface of the transparent protective layer 20. The heat is conducted through the transparent protective layer 20 to the thermosensitive image-forming adhesive layer 25 causing thermally active dye in the heated area of the thermosensitive image-forming adhesive layer 25 to change color. This process is repeated until the desired pattern is imaged on the surface of the thermosensitive image-forming adhesive layer 25. Since the transparent protective layer 20 is transparent, it permits the pattern to be viewed while protecting the thermosensitive image-forming adhesive layer 25 from adverse conditions that would negatively impact the readability of the pattern. The printable multilayer sheet 10 can be cut or separated into smaller labels, each containing a pattern. Printable multilayer sheets 10 can be manufactured in different sizes and length depending on the type printer being used or the desired label.
Once a label 10 has been printed, it can be attached to a desired surface by peeling the release liner 30 off the bottom surface of the thermosensitive image-forming adhesive layer 25, placing the bottom surface of the thermosensitive image-forming adhesive layer 25 against the desired surface and applying temporary pressure to the front surface 20 of the label 10.
The present embodiment uses thermal printing techniques to illustrate the invention however, other embodiments are based on different printing techniques such as light diode technology. Light diode technology uses light to activate a component, similar to a thermal dye. A light receptive dye is placed in the adhesive layer in place of the thermal dye. Light from a diode passing through the clear protective layer activates the light receptive dye causing it to change color similar to heat causing the thermal dye to change color.
In another embodiment, the release layer 30 and thermosensitive image-forming adhesive layer 25 are sufficiently thin for a printer to print through the release layer 30 to the thermosensitive image-forming adhesive layer 25 causing the thermally active dyes to change color and be visible through the transparent protective layer 20. The thermosensitive image-forming adhesive layer 25 must be sufficiently thin so that the heat causes the thermally active dyes to completely change color through the entire thickness of the thermosensitive image-forming adhesive layer 25. Otherwise, the pattern will not visible from the front side of the label 10. In this embodiment, a mirror image of the pattern to be viewed is printed through the release layer 30 (backside of the label 10) and the pattern is properly viewed through the transparent protective layer 20 (front side of the label 10).
While the invention is disclosed in the context of thermal printing on a printable multilayer sheet or label, it will be recognized that a wide variety of implementations may be employed by a person of ordinary skill in the art consistent with the above discussion and the claims, which follow below.
