U.S. patent application number 12/428323 was filed with the patent office on 2010-10-28 for systems and methods for activating thermochromic ink labels.
Invention is credited to Brad Reddersen, Kerry Strand.
Application Number | 20100269454 12/428323 |
Document ID | / |
Family ID | 42990856 |
Filed Date | 2010-10-28 |
United States Patent
Application |
20100269454 |
Kind Code |
A1 |
Reddersen; Brad ; et
al. |
October 28, 2010 |
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.
Inventors: |
Reddersen; Brad; (Pasadena,
CA) ; Strand; Kerry; (Los Angeles, CA) |
Correspondence
Address: |
PERKINS COIE LLP
POST OFFICE BOX 1208
SEATTLE
WA
98111-1208
US
|
Family ID: |
42990856 |
Appl. No.: |
12/428323 |
Filed: |
April 22, 2009 |
Current U.S.
Class: |
53/411 ;
53/131.4; 53/203; 53/461 |
Current CPC
Class: |
B65C 9/0015 20130101;
C09D 11/50 20130101 |
Class at
Publication: |
53/411 ;
53/131.4; 53/203; 53/461 |
International
Class: |
B65B 61/26 20060101
B65B061/26; B65B 11/00 20060101 B65B011/00 |
Claims
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.degree. 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.degree. 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.degree. 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.degree. 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.degree. 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.degree. 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.degree. C. within 3
seconds from the time that movement of the label from the heating
station begins.
Description
BACKGROUND OF THE INVENTION
[0001] The field of the invention is activation of labels using
thermochromic ink as a time/temperature indicator.
[0002] Time/temperature indicators are commonly used on perishable
products, typically food products that require refrigeration to
maintain product quality. Although various types of
time/temperature indicators have been used, they all generally are
designed to provide an indication that the indicator has been
exposed to a temperature above a specified temperature, for more
than a specified period of time. For example, a time/temperature
indicator on a perishable dairy product such as pasteurized milk
may change color, or undergo another form of visual change, if
exposed to a temperature above 5.degree. C. (40.degree. F.) for
more than four hours.
[0003] One type of time/temperature indicator uses an activated
thermochromic material, such as thermochromic ink. Thermochromic
inks change color in response to temperature changes. In use for a
time/temperature indicator, the ink may be printed on a label that
is applied to or wrapped around a specific perishable food item.
When the temperature of the label exceeds a given value, the
thermochromic ink in a typical case darkens noticeably. The
darkening provides a visible indication that the product may have
been exposed to higher temperatures than is appropriate. Some
thermochromic inks must be activated after they are printed onto a
label to be used as a time/temperature indicator. Activation is
achieved by first exposing the thermochromic ink on the label
either to an intense light source or high heat, and then followed
by quickly cooling the thermochromic ink to a very low temperature.
After activation is achieved, the thermochromic ink will retain its
initial color and remain stable or "untripped", unless exposed to a
temperature above a "trip" temperature, for a sufficient amount of
time. The trip temperature is selected based on the particular
temperature requirements of the product that the thermochromic
label is used on, and is achieved via the chemical composition of
the ink. These characteristics of thermochromic materials are well
known, as described for example in International Patent Application
No. PCT/US2003/020537, incorporated herein by reference.
[0004] In view of the requirements for activation for thermochromic
inks as described above, engineering challenges remain in designing
systems and methods for effectively performing activation. It is an
object of the invention to provide improved systems and methods for
achieving activation of thermochromic ink labels.
SUMMARY OF THE INVENTION
[0005] In a first aspect of the invention, a label may include a
thermochromic ink section and a conventional printing area. A
package parameter, such as the weight of a food package or portion
is determined and can be printed in the conventional printing area.
This printing can be accomplished in various ways, including direct
thermal printing. After the conventional printing is completed, at
least the thermochromic ink section of the label is exposed first
to an activation energy source, such as intense light or high heat.
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 a very low temperature. Where heat is
used as the activation energy, the label temperature is typically
at least 100.degree. C. The cooling station typically brings the
label to a temperature below 0.degree. C. The activation energy
source may activate the thermochromic ink with or without
substantial heating of the label.
[0006] In a second aspect of the invention, as applied to food
products, a food package labeling system for refrigerated or frozen
foods includes a scale and a label printer for printing a weight as
measured by the scale on a label. A thermochromic ink label
activator in the system includes a first stage activation energy
source and a second stage rapid label cooling unit. The system also
includes a label transport system for moving a sequence or strip of
the labels through the label printer and thermal label activator.
The labels may have a first area for printing by the label printer,
and a second area containing a thermochromic ink which is activated
by the thermal label activator. The first stage activation energy
source may include a may include a radiant illumination unit, such
as a UV or IR lamp. It may also instead include a contact hot plate
or hot air source to help cause rapid absorption of energy into the
thermochromic ink part of the label. The rapid cooling unit may
include a cold plate moving into momentary physical contact with
the second area of the label.
[0007] The methods and systems of the invention provide for
improved thermochromic ink label activation. Other and further
objects and advantages will become apparent from the following
detailed description of the invention. This description provides
examples of embodiments of the invention and is not intended to be
understood as defining the limits of the scope of invention.
Rather, the scope of the invention is set forth in the claims, and
their equivalents, following the detailed description, and in the
detailed description itself.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] In the drawings, the same element number indicates the same
element in each of the views.
[0009] FIG. 1 is a schematic view of the present labeling
system.
[0010] FIG. 2 is a schematic side view of the thermal activation
unit shown in FIG. 1.
[0011] FIG. 3 is a schematic side view of an alternative labeling
system.
[0012] FIG. 4 is a schematic side view of another alternative
labeling system.
[0013] FIG. 5 is a flow chart showing a label activation
process.
[0014] FIG. 6 is an enlarged view of a label that may be activated
using the systems and methods described.
DETAILED DESCRIPTION OF THE DRAWINGS
[0015] Turning now in detail to the drawings, as shown in FIG. 1, a
labeling system 10 includes a printer 16 and a thermochromic ink
activator unit 20. These and other system components may be
contained within an enclosure or housing 12. The system 10 may also
include a scale 22 and a keyboard/monitor 24, or other user
interface and controller. The printer 16 is electrically linked to
the scale 22. As food portions or packages are placed on the scale
22, the printer 16 prints the package weight on a printing section
of a label 34. The printer 16 may use conventional ink on paper
printing techniques.
[0016] In the design shown in FIG. 1, labels 34 are provided on
backing strip or tape 32 on a spool 14. FIG. 6 shows an enlarged
view of a label 34. The printer 16 prints on a printing section 114
of the label 34. The printer 16 may be a direct thermal printer
using temperatures over 150.degree. C. The label also has a
trans-informational section 110A including a thermochromic ink.
Additional details on the physical characteristics of the label are
provided in U.S. Pat. No. 7,157,048, incorporated herein by
reference.
[0017] Referring still to FIG. 1, a label drive system 18 moves the
strip 32 through or past the printer 16 and the activator unit 20.
The activator unit 20 includes a first stage activation subsystem
38 and a cooler 50. As shown in FIG. 2, the first stage activation
system may include a radiant lamp 40 and a reflector 42 to energize
a label 34 positioned at a first or activation energy station. One
or more lenses 44 may optionally be used. The lamp 40 may be a
linear UV lamp. Various other types of radiant light illumination
systems may alternatively be used. Conductive and convective
heaters, and combinations of radiant light illumination systems,
plus conductive and convective heating, may also be used. Radiant
light illumination system are advantageous as they do not require
any moving parts and can be calibrated to provide uniform and
precise energizing of the label as the first stage of activation.
They also do not require physical contact with the label, which can
cause inadvertent displacement of the thermochromic ink on the
label. Direct thermal printing may used for the conventional
printing, and the first stage of label activation for the
thermochromic ink designed for this process and may be activated at
slightly over about 100.degree.C. Then because the activation
temperatures used are lower than the temperature required to print
with direct thermal printing, the first stage of activation does
not damage the printed information on the label, even if the
printed information is exposed to the first stage of
activation.
[0018] In the particular design shown in FIG. 2, the cooling unit
50 includes a thermoelectric cooler 56 having a cold plate 54
associated with a cooling station 60. An exhaust fan 58 removes
heat from the thermo-electric cooler 56, in a direction away from
the cold plate 54. A cold plate actuator 62 moves the cold plate 54
into and out of contact with an activated label 34 moving into the
cooling station 60 from the activation energy station 46. A
pressure pad 52 may optionally be aligned with the cold plate 54.
Of course, various other equivalent types of cooling units and
cooling techniques may be used. A de-icer 70 may be used to avoid
build up of ice on the cold plate, so that the cold plate 54
remains efficient in cooling labels 34 during operation of the
labeling system. The de-icer 70 may use various known techniques
for removing ice, including heating, chemical removal, or physical
removal using moving mechanical elements and/or streams of liquids
or gases.
[0019] Referring to FIGS. 1 and 2, the labels 34 may have an
adhesive back and be provided on the label strip 32, with a small
uniform gap between each adjacent label. The label strip 32 extends
through the printer 16 and the thermal activator unit 20. Alignment
guides 35 may optionally be used to keep the label strip 32
properly aligned and positioned within the printer 16 and the
activator 20. However, in most designs operating with a label
strip, alignment guides are generally not needed. As shown in FIG.
2, a base plate 30 may extend at least through the activator 20, to
support the label strip 32 vertically, while the alignment guides
35 (if used) support or guide the label strip 32 laterally. The
label drive system 18 pulls the label strip 32 from the spool 14,
through the printer 16 and the activator 20, typically in uniform
steps to sequence labels 34 on the label strip 32 through the
labeling system 10. The label drive system 18 may advance the label
strip 32 via pinch rollers 18, reciprocating elements, or similar
designs. The label drive system may be set up to contact only the
edges of the label strip 32, so as not to contact the labels
themselves.
[0020] In operation, the labeling system 10, in a typical setup,
may be located in the meat or fish department of a supermarket or
similar retail store. The system operator uses the keyboard,
control panel or other interface 24 to turn the system 10 on, and
optionally to check that the system 10 is ready for operation.
These checks may include indications that a sufficient label strip
32 is loaded onto the spool 14, and that the system components such
as the scale 22, printer 16 and activator 20 are ready for
operation. One or more test labels may optionally be printed and
activated.
[0021] The user places a food portion or package on the scale 22.
The scale 22 may optionally be separate and remote from the
labeling system 10, depending on the setup and work flow. The
weight of the food portion or package as measured by the scale is
provided to the printer 16 as an electrical signal. The scale 16
prints the weight onto a label. The scale may optionally print
additional information as well, such as price per pound, time,
date, store number, etc. The food portion may be placed into a
tray, such as a Styrofoam tray or other single use support. The
food portion may also be wrapped, or unwrapped, when weighed. After
the weight is printed on the label 34, the drive system 18 is
momentarily actuated to move the printed label from the printer 16
to the activation energy station 46. During this movement, a
following adjacent label on the label strip 32 moves into the
printer 16.
[0022] The first stage activation system 38 may generally operate
at a steady state. Regardless of whether a radiant illumination
source or a convection or contact heat source is used to energize
the label at this stage, it is helpful to have the heat source or
the lamp 40 left on when the system 10 is in constant use. As a
result, energy absorption at the activation energy station 46 is
consistent, based on the design of the activation system
components, which may include a specific lamp and optics or
specific heating element devices. If the system 10 is in
intermittent use, the activation energy station 46 may switch on
and on according to various timing sequences, as controlled or
programmed by the controller 25. The on/off operation of the first
stage activation system may also be linked to the operation of the
printer 16, since operation of the printer 16 precedes operation of
the first stage activation system 38.
[0023] FIG. 5 shows the steps associated with the activator unit
20. At step 80, a label 34 on the strip 32 is positioned to move
into the printer 16. This step may be achieved via the use of the
alignment guides 35 and the base plate 30. Alternatively, some
types of label strips 32 may feed directly from a spool 14 (or
other bulk label storage element) into the printer 16. At step 82,
the label 34 moves into the printer 16. The printer 16 prints the
food weight and/or other information on the printing section 114 of
the label 34. The printed information may be generated by the scale
and/or the keyboard 24 or electronic controller 25. The drive
system 18 then incrementally advances the label strip 32, moving
the now printed label 34 into the activation energy station 46.
Next, at step 86, in the activation energy station or system 46,
either exposure to high radiant energy or high heat is applied to
the label 34. If direct heat is used at this stage, the label 34
may be heated to an elevated temperature, typically a temperature
of between 80 and 150.degree. C. and for a period of between 0.5
and 4 seconds. High energy absorption at this first stage of
activation causes the molecules of the thermochromic ink to change
shape and unfold. This changes the optical properties of the ink.
The precise temperatures and/or illumination exposure requirements
at this energy activation stage or step will vary with the type of
thermochromic ink used, and may be obtained from the ink
manufacturer, or determined empirically.
[0024] After the activation energy step 86, the drive system 18
again incrementally advances the label strip to move the label 34
into the cooling station 60. When the thermochromic ink is no
longer exposed to the activation energy source, it tends to revert
to its original state. To prevent this reversion, and to preserve
the utility of the label 34 as a time/temperature indicator, the
label is quickly cooled at the cooling station, at step 90. This
step is performed by cooling the label 34 to a typical temperature
of from -5 to -25.degree. C. or -10 to -20.degree. C. for 1, 2, 3,
4 or 5 seconds. This cooling completes the activation of the
thermochromic ink on the label 34. Colder temperatures and longer
cooling times may be used, but generally are not necessary. At step
92 in FIG. 5, the drive system 18 again advances the label strip 32
moving the now fully activated label out of the activator unit
20.
[0025] To achieve rapid cooling of the label 34, the cooler 50
including the cold plate 54 may be used. In this case, the cold
plate actuator 62, optionally controlled by the controller 25,
quickly moves into contact with the activation area 110 on the
label 34. The label 34 is lightly pressed between the cold plate 54
and an underlying supporting surface, such as the pressure pad 52
of a base plate 30. To reduce the time delay between exposure to
the activation energy source and cooling, the label drive system 18
may advance the label strip quickly, so that movement of the label
into the cooling station 60 takes less than 1, 0.5 or 0.3
seconds.
[0026] The cooling station 60 may also be adjacent to the
activation energy station 46, to reduce the time required for
movement of the label into the cooling station. The minimum spacing
between the activation energy station 46 and the cooling station 60
will depend in part on the size of the labels 34. Typical labels
are about 5-14 cm (2-5 inches) long (dimension L in FIG. 6) and 5-9
cm (2-3.5 inches) wide. The strip 32 may be 2-10 cm wider than the
label 34. With 8 cm.times.8 cm labels, the centers of the
activation energy station and the cooling station may be less than
16, 12, or 10 cm apart. The activation area or field 100 of the
label 34 is generally at least 5 cm wide and 2 cm long. The
activation energy station 46 and the cooling station 60 may be
dimensioned based on the activation area. While the labels 34 are
generally adhesive back paper labels, labels of other materials,
such as plastic, may also be used.
[0027] After weighing, the food package is wrapped (unless it has
already been wrapped before weighing). Wrapping may be done
manually by the operator or automatically via a wrapper or packager
26 associated with the labeling system 10. The now activated label
is applied to the food package. This may be done manually by the
operator or automatically by a label applicator 28.
[0028] The activated label is temperature sensitive. If the label
is exposed to a temperature above a selected trip temperature, the
thermochromic ink layers on the label will begin to darken or
"trip". The trip temperature is determined by the make up of the
thermochromic ink. A typical trip temperature is 4.degree. C.
(40.degree. F.). This trip temperature is useful for many
perishable food products that require refrigeration. The activated
label will remain stable and un-tripped for virtually as long as it
remains at 4.degree. C., or lower. If exposed to temperatures over
about 4.degree. C. for a sufficient trip time period (usually
several hours), the label will trip as the thermochromic layers of
the label permanently darken. The darkened label provides a visual
indication that the food product has been exposed to too high a
temperature for too long of a time during some point in its
handling and storage, prior to reaching the point-of-sale, or some
other interim scanning or inspection point.
[0029] Too avoid initiation of tripping the labels immediately
after they are activated, the labeling system may be located in an
environment at 4.degree. C. or less. For use on frozen foods, the
labels 34 have a trip temperature of 0.degree. C. or less. Other
trip temperatures may be used for other types of products, such as
medical products including pharmaceuticals, blood and organs,
vaccines, live organisms, etc. Activated labels may also be used on
chemical products, such as paint. In addition to placing labels 34
onto food, beverage, wine and candy packages or containers,
activated labels may be used on raw materials, shipping containers,
and the packaging or containers of various temperature sensitive
products.
[0030] FIG. 3 shows an alternative design similar to the system 10
shown in FIGS. 1-2, but operating with individual labels moved on a
conveyor belt 36. In this design, labels may be placed manually
onto the conveyor for movement to the activation energy station 46
and the cooling station 60. Since unlike the system 10 shown in
FIGS. 1-2, the labels are not on a label strip 32, guides 35 are
used to keep the labels properly aligned.
[0031] FIG. 4 shows another alternative design similar to the
system 10, but with two coolers 50 positioned on opposite sides of
the label 34. In this design, upper and lower (or left and right)
cooling plates 54 move against upper and lower surfaces of the
label. Faster cooling may be achieved by cooling both sides of the
label simultaneously. Optionally, either one of the two cooling
plates shown in FIG. 4 may be fixed in place, essentially forming a
cooling base plate 30. As shown in FIG. 4, a similar concept may be
used for exposing the label to activation energy, such as UV or IR
radiation, or to thermal heating. In FIG. 4, a first activation
energy source or heater 38, shown in solid lines, exposes or heats
a first side of the label. If desired, a second activation energy
source or heater, shown in dotted lines, may be used to expose or
heat the second side of the label. However, as the labels are less
sensitive to heating times than to cooling times, usually a single
activation energy source 38 will be sufficient.
[0032] Thus, a novel labeling system and thermal label activator
have been shown and described. Various changes and substitutions
may of course be made without departing from the spirit and scope
of the invention. The invention, therefore, should not be limited,
except by the following claims and their equivalents.
* * * * *