VARIABLE PRINTING OF THERMOCHROMIC CODES
RELATED APPLICATIONS
[0001] This application claims benefit of priority to provisional application serial number 61/526,211 filed August 22, 2011, which is incorporated by reference to the same extent as though fully replicated herein.
BACKGROUND
[0002] Printed articles of manufacture may contain hidden codes or other indicia that may be used to redeem promotional materials or other valuable things. By way of example, a state lottery may be conducted using printed cards that utilize a plasticized ink to cover an area of the card stating a cash amount that may be revealed by scratching off the plasticized ink. A bottled soft drink may be sealed with a crown, the inside of which contains a promotional code that is redeemed by use of the Internet. A candy bar wrapper may also have an interior surface bearing this type of code, which is revealed only after the candy bar is unwrapped. Promotional indicia may be printed on bars of soap as taught in United States Patent No. 7,743,704.
[0003] Thermochromic inks are not generally regarded as being useful in the variable printing of promotional or other codes. This is because thermochromic inks contain thermochromic pigments in the form of microcapsules that are typically melamine -formaldehyde microcapsules, for example, as taught by United States Patent No. 5,591,255 issued to Small et al., which is hereby incorporated by reference to the same extent as though fully replicated herein. These microcapsules range in size with particle diameters from 0.5 to fifteen microns. These particle sizes may not work well with individually configurable printing systems, such as ink jet printing.
SUMMARY
[0004] The present disclosure overcomes the problems outlined above and advances the art by providing methods and apparatus for variable printing of promotional or other codes using thermochromic inks.
[0005] In one embodiment, label is provided that supports variable printing of codes using thermochromic ink. A background may be printed using a background ink having a first color. A thermochromic ink is printed to overlay the background ink, and there is adopted a means for concealing a code that is revealed when the thermochromic ink undergoes a color transition. This means may be, for example according to one embodiment, a code printed over the background ink, the code being printed with an ink that matches the background ink. The thermochromic ink is colorless at room
temperature and exhibits a color change upon sufficient cooling to reveal the code.
[0006] In one embodiment, the means for concealing may be a code printed in thermochromic ink over the background ink. The code is printed with an ink that is colorless at room temperature and exhibits a color change upon sufficient cooling to reveal the code.
[0007] In one embodiment according to these instrumentalities, a label is provided to supports use of variable printing of matrix codes using thermochromic ink. A first matrix code is printed using a first thermochromic ink that is colorless until cooled to a first predetermined temperature which renders the first matrix code visible in a first color. A second matrix code printed using a second thermochromic ink that provides a second matrix code when cooled to a second predetermined temperature which renders the second matrix code visible in a second color. The first thermochromic ink and the second thermochromic ink are clear at normal room temperature.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Figure 1 shows a system for variable printing of thermochromic codes according to one embodiment;
[0009] Fig. 2 shows a label that has been partially printed using the system of
Fig. 1 ;
[0010] Fig. 3 shows a label that has been completely printed using the system of Fig. l ;
[0011] Fig. 4 shows the label of Fig. 3 adhered to a beverage bottle;
[0012] Fig. 5 shows a label in successive stages of printing according to a laser ablation embodiment;
[0013] Fig. 6 shows a label in successive stages of printing according to an ink overlay embodiment;
[0014] Fig. 7 shows a label in successive stages of printing according to an ink overlay embodiment;
[0015] Figs. 8A and 8B show a label in successive stages of printing according to a two dimensional matrix overlay embodiment.
DETAILED DESCRIPTION
[0016] System 100 contains a roll 102 of material that is continuously unrolled to form a web 104. The web 104 may be, for example, paper or plastic material adhered to a release layer from which may be produced selectively detachable adhesive labels, or a sheet of aluminum. Print stations 106, 108 apply ink to the passing web 104. Print station 110 is for rotogravure printing as is known in the art. A laser station 112 is positioned for operations on the printed web 104. An optional platen assembly 114, 116 is positioned for vertical strokes 118 to cut selected portions of the web 104 into detachable labels (not shown). The printed web 104 is rolled into a demountable spool 120 for later use. A programmable computer 122 governs operations of system 100.
[0017] Fig. 2 shows a label 200 that contains surface 202 with indicia including a promotional code 204 in area 206. The promotional code 204 may be printed using thermochromic ink of any color, such as thermochromic ink that may be purchased on commercial order from Chromatic Technologies, Inc. of Colorado Springs, Colorado. The area 206 may be left unprinted with ink or may be covered with ink that differs from the thermochromic ink of code 204. The promotional code 204 and any ink optionally placed in area 206 may be printed, for example, using print head 106 (see Fig. 1). As shown in Fig. 3, the area 206 and the code 204 (not shown) have been covered by ink 300, as applied by print station 108 (See Fig. 1). The print station 110 has applied additional ink to form indicia 302, 304. The indicia 304 optionally provides instructions for use of the promotional code 204 at print station 110, such as "Chill to Reveal." Fig. 4 shows the label 200 applied to a bottle 400.
[0018] The sequence of printing on area 206, the promotional code 204 and the ink 300 may be provided in any combination. For example, in one embodiment,
neither the ink on area 206 or the ink 300 are required. In one embodiment, indicia on the label 200 may consist only of the promotional code 204 and the top coat of ink 300.
[0019] The spool 120 shown in Fig. 1 may contain a plurality of such labels 200, each bearing a different promotional code 204 as directed by the programming of computer 122 (see Fig. 2). The labels may be detached from spool 120 and applied to the bottles by automated equipment as is well known in the art. The spool 120 is not essential and the web 104 run for direct use at any downstream process.
Laser Ablation
[0020] The promotional code 204 may be formed using laser ablation. One solution is to perform laser ablation of the ink. By way of example, screen printing may be used to cover entirely the area 206 of Fig. 2 with a band of thermochromic ink that is colorless when warm and which exhibits a color change when chilled. This color change may be, for example, from clear to blue. The laser station 112 ablates unwanted portions of ink in area 206 to leave the promotional code 204 using the methodologies reported, for example, in United States Patent Publication No. US 2009/0128860 to Graushar et al., which is incorporated by reference to the same extent as though fully replicated herein. The laser wavelength, pulsing frequency and applied power may be tuned to
accommodate a particular thermochromic inks. While some of the 'clear' thermochromic inks used in this application are undetectable, other inks may leave a residue that is slightly visible. In these circumstances the top coat 300 (see Fig. 3) may be used to hide this residue.
[0021] In one embodiment, the area 206 may be screen printed with a colored ink, such as a white ink, and topcoated with a thermochromic ink that is clear at normal room temperature. The thermochromic ink may be laser ablated to form code 204 while leaving intact the ink over area 206. The thermochromic ink forming code 204 changes color when chilled to a predetermined temperature to contrast with the in on area 206, for example, forming the code 204 in blue on the white background of area 206. Ink 300 may seal or protect the code 204 and cover any ascertainable differences, such as a change in glossiness that might otherwise reveal code 204 to the naked eye even before the label is cooled to the predetermined color transition temperature.
[0022] In another example, Fig. 5 shows a label 500 at different stages of printing, 502 (Fig. 5A), 506 (Fig.; 5B) and 508 (Fig. 5 C). A background area 504 is printed at stage 502. This background may be, for example, a white or gray background. A thermochromic band 508 may be printed at stage 506 and laser ablated at stage 510 to form promotional code 512.
Direct Print Over Thermochromic Band With Matching Background
[0023] A thermochromic pigment is prepared as taught in United States Patent No. States Patent No. 5,591,255, except the pigment is screened to eliminate larger particle sizes. By way of example, the pigment may be centrifuged to separate particles by density gradient, and/or passed through a polyester or nylon screen, such as those obtainable on commercial order from Miami Aqua-culture of Boynton-Beach Florida, or any other source of micron screens known to the art. The screening may eliminate particles of over a certain size, such as by eliminating particles over a size that would be problematic to ink jet printing. Generally, this should eliminate particles over about 5 microns in diameter. Preferably, the particles have a size less than 3 microns and this is most preferably less then 1 micron. The screened pigment may then be used as pigment in a conventional formulation for ink jet ink, for example, as taught in United States Patent No. 5,207,824 issued to Moffatt et al., which is hereby incorporated by reference to the same extent though fully replicated herein. In preparing the ink, care is taken to select ingredients from the list of optional ingredients in Moffat et al. so as to avoid use of aldehydes, ketones, and diols, and most aromatic compounds. The ink so prepared may be used in the system 100 for ink jet printing of thermochromic inks.
[0024] Fig. 6 shows a label 600 at various stages 602, 604, 606 of printing. At stage 602, background ink 608 is printed, such as a white background. Stage 604 entails printing a thermochromic band 610 over the background ink 608 by screen printing or, alternatively, ink jet printing using the ink described above. A promotional code 612 is printed over the thermochromic band 610 using the same ink used as the background ink 608. The thermochromic band 610 is colorless at normal room temperature and changes color when cooled to a predetermined temperature. This predetermined temperature may be, for example, temperature of 5°C indicating that a
beverage has cooled to an optimum temperature to enhance organoleptic properties of a beverage. The color transition renders the code 612 visible to the naked eye, as the code 612 contrasts with the thermochromic band 610. This color transition of the
thermochromic band 610 may be, for example, from clear to blue. The promotional code 612 is optionally topcoated with a clear coating 614 to hide differences in glossiness between the background ink 608 and code 612.
Direct Print Over Thermochromic Band With Matching Colors
[0025] Fig. 7 shows a label 700 at various stages 702, 704 of printing. At stage 702, a thermochromic background ink 706 is printed. At stage 706, a promotional code 708 is printed. The ink used to print the promotional code matches exactly the color of the thermochromic background ink 706 at normal room temperature, such as matching burgundy colors. The thermochromic background ink 706 changes color when chilled to a predetermined temperature, for example, transitioning from burgundy to blue. As shown in the expanded view of Fig. 7A, the promotional code 708 may be cross-hatched with thermochromic ink to hide slight differences between the background ink 708 and the thermochromic ink used to make the promotional code 708.
Matrix Code
[0026] Fig. 8A is a first two dimensional matrix code 800 that may be printed as a label 802 using a first thermochromic ink that is clear at normal room temperature and transitions to a visible color, such as orange, upon being cooled to a first
predetermined temperature. The label 802 is printed with a second thermochromic ink having a color transition temperature lower than the first predetermined temperature. The second thermochromic ink has, for example, transitions from clear to a color, such as black, to revel a second matrix code 804. Thus, the label 802 is provided with a first matrix code 800 that may b e revealed when a beverage is chilled to a state of being refrigerator code, and another matrix code 804 when the beverage is chilled to being freezer cold. The matrix codes 800, 804 may be scanned using, for example, an iPhone application and transmitted to a central server for processing according to promotional contest rules.