Systems and methods for activating thermochromic ink labels

Abstract

In methods and systems for activating a label including a thermochromic ink used as a time/temperature indicator, the label has a first or printing section, and a second or thermochromic ink section. A package parameter, such as the weight of a food package or portion, is determined and printed on the printing section of the label. The label is advanced to an activation energy station. At least the thermochromic ink section of the label is exposed to activation energy, such as heat or radiation. The label is then quickly moved to a cooling station. At the cooling station, at least the thermochromic ink section of the label is quickly cooled, to activate the label for use as a time/temperature indicator.

1 . A food package labeling system for refrigerated or frozen foods, comprising:
 a scale;   a label printer electrically linked to the scale;   a label activator for activating a food package label, the activator including an activation energy unit and a rapid label cooling unit; and   a label transport system for moving a sequence of labels containing thermochromic ink through the label printer and label activator.   
     
     
         2 . The labeling system of  claim 1  further comprising a strip of labels on a spool, and with the label transport system comprising contact elements that contact the strip of labels as the strip exits from the thermal label activator. 
     
     
         3 . The labeling system of  claim 1  further comprising an automatic food package wrapper adapted for wrapping a food package after the food package is weighed on the scale. 
     
     
         4 . The labeling system of  claim 1  further comprising a label applicator adapted to attach an activated food label onto a food package. 
     
     
         5 . The labeling system of  claim 1  with the activation energy unit comprising a radiant heater, a UV light source, and/or an IR light source. 
     
     
         6 . The labeling system of  claim 1  with the cooling unit having a cold plate and an actuator for moving the cold plate into contact with label. 
     
     
         7 . The labeling system of  claim 6  further comprising a flexible pressure pad associated with the cold plate. 
     
     
         8 . The labeling system of  claim 1  with the label transport system comprising a conveyor belt. 
     
     
         9 . A food package labeling system for refrigerated or frozen foods, comprising:
 a label printer;   a label activator for activating a food package label, the activator including an activation energy station having a radiant energy source, with the label provided on a strip of labels and the label containing a thermochromic element, the radiant energy source fixed in position relative to the activation energy station, and the label activator also including a cooling station adjacent to the activation energy station, a cold plate associated with the cooling station, and an actuator for moving the cold plate and the label together into physical contact with each other at the cooling station; and   a label strip transport system for moving the strip of labels through the label printer and label activator.   
     
     
         10 . The food packaging labeling system of  claim 9  with the activation energy station having a first dimension in the direction of movement of the strip, and with the cooling station having a second dimension in the direction of movement of the strip, and with the activation energy station spaced apart from the cooling station in the direction of movement of the strip by a dimension less than the first dimension and less than the second dimension. 
     
     
         11 . The food packaging system of  claim 9  with the activation energy station continuous with the cooling station. 
     
     
         12 . The food packaging system of  claim 9  further comprising a scale for weighing food, with the scale electrically linked to the label printer. 
     
     
         13 . A method of labeling food packages, comprising:
 providing a label including a thermochromic ink section and a printing section;   determining a food parameter;   printing the food parameter on the printing section of the label;   exposing at least the thermochromic ink section of the label to activation energy at an activation energy station;   moving the label to a cooling station;   cooling the label at the cooling station to a temperature below 0° C., within 3 seconds from the time that movement of the label from activation energy station begins.   
     
     
         14 . The method of  claim 13  wherein the label is cooled at the cooling station to a temperature below −15° C. within 3 seconds from the time that movement of the label from the activation energy station begins. 
     
     
         15 . The method of  claim 13  wherein the exposing step comprises heating the label. 
     
     
         16 . The method of  claim 15  further comprising heating the label to a temperature above 100° C. 
     
     
         17 . The method of  claim 13  wherein the exposing step comprises exposing the label to radiant energy. 
     
     
         18 . The method of  claim 17  wherein the radiant energy comprises UV or IR light. 
     
     
         19 . The method of  claim 13  further comprising printing the food parameter via direct thermal printing. 
     
     
         20 . The method of  claim 13  further comprising cooling the label via a spray of a cooling medium. 
     
     
         21 . The method of  claim 21  wherein the cooling medium comprises a cooling gas. 
     
     
         22 . The method of  claim 21  wherein the cooling gas comprises liquid nitrogen or cooled air. 
     
     
         23 . The method of  claim 13  wherein the label is cooled at the cooling station to a temperature below −15° C. within 1 second from the time that movement of the label from the heating station begins. 
     
     
         24 . The method of  claim 13  wherein the food parameter is weight, and the food parameter is determined by weighing the food. 
     
     
         25 . The method of  claim 13  wherein the cooling is performed by contacting the thermochromic ink section of the label with a cold plate. 
     
     
         26 . The method of  claim 25  wherein the cooling is performed by pressing the thermochromic ink section of the label between the cold plate and a pressure surface. 
     
     
         27 . The method of  claim 26  further comprising de-icing at least one of the cold plate and the pressure surface by applying heat. 
     
     
         28 . A method of labeling food packages, comprising:
 providing a label including a thermochromic ink section and a printing section;   determining a food parameter;   printing the food parameter on the printing section of the label;   heating at least the thermochromic ink section of the label to a temperature of greater than 100° C. at a heating station;   moving the heated label to a cooling station;   cooling the heated label at the cooling station to a temperature below 0° C., within 3 seconds from the time that movement of the label from heating station begins.   
     
     
         29 . The method of  claim 28  wherein the heated label is cooled at the cooling station to a temperature below −15° C. within 3 seconds from the time that movement of the label from the heating station begins.