METHOD OF PRINTING OF TAMPER PROOF UNIQUE CODES IN A
PACKAGING LAMINATE USING THERMAL TRANSFER OVERPRINTING
(TTO) TECHNOLOGY AND SYSTEM THEREOF
FIELD OF INVENTION
This invention relates to a method of printing tamper proof unique codes in a
packaging laminate using a thermal transfer overprinting technology and the
system thereof. More particularly, the present invention relates to a method of
printing with help of an available printing facility for printing non-repetitive tamper-
proof auto generated code from a group of codes on a packaging laminate.
In this specification the term codes, as used, refers to alpha-numerical or
numerical or symbols or combinations thereof and the term pattern includes one
or more pictures, logos, images, designs, monograms, graphics, slogans, trade
marks or names, devices, or phrases in single or multi colours or combinations
thereof.
BACKGROUND
Generally in recent increasing retail market of packaging, consumer products are
packed in packages made of flexible packaging laminates, which are made by
laminating two or more substrates using adhesives coating or extrusion. To
increase aesthetic value and awareness of consumer products and to attract
customers to promote the sales, lucrative gifts and incentives are sometimes
offered for selected purchases of products by providing promotional / winning
codes in the packages without losing the attractiveness of the pack. Usually, the
codes are printed on the outer surface or on inner outer surface of the packaging

laminates after the lamination. The printing of the codes on the outer or inner
outer surface of the packaging laminates is usually carried out by Inkjet screen or
pad printing. By this printing, printed codes on the outer or inner outer surface of
the packaging laminates are exposed and can be easily tampered with. Another
disadvantage of codes printed on the inner outer surface of the packaging
laminates is its coming into contact with the contents of the packages. This is
highly undesirable especially in the case of consumer products like food or
personal or oral products or medicines, which can be contaminated.
The codes are generally printed at the inner surface of the outer or outermost
substrate of the laminate where the desired pattern is printed, the printed
substrate is laminated with the remaining substrate(s) of the laminate so as to
sandwich the printed matter i.e. the pattern and the codes. In such a laminate,
then printed codes can be visible and transparent along with the printed pattern
when viewed from the outer side of the laminate. Alternatively, the outer
substrate whose inner surface is printed with the desired pattern, is laminated
with an intermediate substrate and the codes are printed on the intermediate
substrate. The intermediate substrate is laminated with another transparent
substrate so as to sandwich the printed codes and conceal or hide the same
when viewed from the outer side of the laminate. The pattern and codes are
usually printed by Gravure or Flexoprinting, in which the pattern and codes to be
printed on the respective substrates are etched or impressed upon the Gravure
cylinders or Flexoplates. Because of the limited number of the Gravure cylinders
or flexoplates corresponding to the number of ons or ups (i.e. packaging strips or
sections) across the width of the laminates, the number of different codes that
can be printed is limited and the codes are repetitive in each repeat of the ons
and ups. The reduced surface area of the Gravure cylinders or flexoplates also
limits the size of the codes. As the number of different codes that can be printed
is limited, unique codes cannot be allocated to each of the ons or ups to be
formed into packages for the products so as to identify the packages by the
respective codes or so as to serve as security seal or stamp for the respective

packages. The codes so provided are, however, within the laminates and are
tamper-proof.
SUMMARY OF INVENTION
An object of the invention is to provide a method of printing/device for printing
unique tamper-proof codes in a packaging laminate in a transparent or non-
transparent manner, which method is simple and easy to operate/carry out.
Therefore such as herein described there is provided a method of printing of
tamper proof unique codes in a packaging laminate using thermal transfer
overprinting (TTO) technology comprising steps of: providing a primary
printable substrate which is made to pass through different printing stations to
get printed in Gravure/Flexo printing machine. The printed substrate is next to
feed on Unwinder of Doctoring/Rewinding/Inspection machine. TTO coder is
made to be fitted on Unwinder or Rewinder side of
Doctoring/Rewinding/Inspection machine according to requirement. After getting
signal from Rewinding machine Print head of TTO unit get activated and made to
print non repetitive unique codes, patterns etc. on reverse side within registered
block which is printed on primary substrate in Printing machine. Laminating the
TTO coded substrate with a transparent intermediate substrate; unique non
repetitive codes get sandwiched between the substrate. In case any opaque
intermediate substrate present in laminate, non-repetitive unique codes is made
to be printed in same way described above on Rewinding machine without/with
registered block in printed substrate and get laminated as described in Fig No. 3
with a transparent substrate thereby making the codes abrasion proof and
tamper resistant.

Another object of the invention is to provide a method of printing /a packaging
laminate/a device for printing unique tamper-proof codes in a packaging laminate
in a transparent or non-transparent manner, which codes can serve as winning
codes for selected purchasers of the products packed in packages formed with
the packaging laminate.
Another object of the invention is to provide a method of printing/a packaging
laminate/ a device for printing unique tamper-proof codes in a packaging
laminate in a transparent or non-transparent manner, which codes can serve as
identification codes or as security seals or stamps for the products packed in
packages formed with the packaging laminate.
Another object of the invention is to provide a method of printing/a packaging
laminate/ a device for printing unique tamper-proof codes in a packaging
laminate in a transparent or non-transparent manner, which codes do not come
in contact with the contents of the packages formed with the packaging
laminates.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
A detailed description of the invention is described below with reference to the
diagram
Figure 1 and 1A, illustrates a schematic diagram of Gravure printing process in
accordance with the present invention;
Figure 2 illustrates the schematic diagram of Rewinding and Thermal transfer
overprint (TTO) Coding Process in accordance with the present invention;
Figure 2A illustrates a schematic diagram of Thermal Transfer Overprint(TTO)
Process in accordance with the present invention;
Figure 3 illustrates the schematic diagram of lamination with secondary substrate
in accordance with the present invention; and

Figure 4 illustrates the process flow chart in accordance with the present
invention.
DETAILED DESCRIPTION
This present disclosure relates to a method of printing auto generated
tamperproof non repetitive codes in packaging laminate in transparent and
nontransparent manner, comprising TTO printing. In TTO Method, the substrate
to be printed offline continuously passes under the TTO printer unit which is fixed
on the Inspection/Rewinding machine. TTO print heads are aligned according to
number of ons or ups across the width of the printed substrate or laminate. The
printing by print heads are being controlled by programmable digitally controlled
user interface.
As shown in Fig 2, the Doctoring / Rewinding / Inspection machine comprises
Unwinder I, Rewinder 1°, few idle rollers, Nip roller, TTO unit, Lay on roller,
Printed substrate.
While printing outermost substrate by Gravure or Flexo printing method as shown
in Fig 1 & 1A, a separate registered block is printed on which the code will be
printed further and finally laminated with the remaining transparent substrate for
providing a sealant layer. Due to presence of the registered block, the codes can
be concealed easily to restrict it's visibility from outermost substrate of the
package.
In case of any opaque intermediate substrate to be placed in the laminate
according to the product requirement/customer's requirement, the TTO printing is
done on the inner side of the intermediate substrate before laminating the sealant
layer which is transparent in nature.

Preferably the said procedure is applied on the packaging material which is
flexible in nature. The considered substrates are as under:
Printable substrates :- Natural Polyester film (PET), Bi-axially oriented poly
propylene ( BOPP), Cast poly propylene (CPP), polyethylene (PE), paper,
aluminum foil etc.
Intermediate substrates (Opaque in nature):- METPET, MET BOPP,
METCPP, Paper, Aluminum Foil, etc
To facilitate the disclosed method a device is provided for printing auto-
generated, unique, tamper resistant codes in a packaging laminate in transparent
or non-transparent manner. The device comprises of a thermal print head and
thermal transfer ribbon as shown in Figure no. 2 and 2A. The print head
comprises of a ceramic coating which is covering a row of thermal pixels which
are activated by the tiny resistors mounted inside the print head. When a signal is
send through inspection/rewinding machine to the TTO unit, it transmits the auto-
generated, unique, tamper resistant codes to be printed on the registered block
of the printable or intermediate substrate which is passing from the unwinding to
rewinding roller.
The printed substrate (Gravure or Flexo printing process) with registered block
preferably used on the Unwinder I is the inner of the outer of opaque
intermediate substrate of the packaging laminate. The above mentioned
substrate is passing through different rollers which use to guide and maintain
tension of the substrate throughout the path way. The TTO coding printer is
positioned on the same side of the unwinder from which the substrate passes to
the Rewinder. The print head of the TTO unit is activated after getting signal from
the Inspection machine and transfer melted ink from the thermal transfer ribbon
on the substrate.

Inventive step
a) The normal TTO printing or any other coding printing facilities are
available only to print on the outermost surface area of the laminate. In
this case, the TTO application has been done in the reverse side of the
printed substrate which is registered with auto generated, unique, tamper
resistant codes, after doing the final lamination the said registered codes
has been sandwiched .Hence this is abrasion proof and tamper resistant.
b) As the ink of the printed code is lying in the sandwich layer therefore
there is no chance of direct contamination between the ink and product
packed therein.
c) This winning / promotional/ identification /security seal stamp printed on
the inner part of the product packed in the packages therefore this
particulars can't be visible from the outside of the package.
d) It will not loose the aesthetic value of the package.
e) In Gravure printing or Flexo printing procedure the printing cannot be done
in non repetitive manner as well as the size of the code remains fixed, as
there is an area constraint in Gravure cylinders and flexo plates which we
can be done in TTO process.
PRINTING (GRAVURE) PROCESS :
A rotogravure printing machine as shown in Fig 1 & 1A consists of printing units
comprise of at least one station in Ref. Fig. No. - 1A) for each color ink (T in Fig.
No- 1A), typically CMYK or Cyan, Magenta, Yellow and key (printing terminology
for Black), but the number of units varies depending on what colors are required
to produce the final image. There are five basic components in each color unit:
an engraved cylinder 'd' whose circumference can differ according to the layout

of the job; an ink tray 'e'; a doctor's blade 'g'; an impression roller 'a', a drying
unit '3'.The ink is made to be applied directly to the cylinder 'd' and transferred
from the cylinder to the substrate 'h'. While the machine is in operation, the
engraved cylinder 'd' is kept partially immersed in the ink tray 'e' for filling the
recessed cells.
As the cylinder'd' rotates, it draws ink out of the tray 'e' with it. Acting as a
squeegee, the doctor blade 'g' scrapes the cylinder'd' before it makes contact
with the substrate, removing excess ink from the non-printing (non-recessed)
areas and leaving in the cells the right amount of ink required: this tool is kept
quite close to the substrate so that the ink left in the cells does not have enough
time to dry.
Next, the substrate is made to pass between the Impression rollers 'a' and the
Gravure cylinder 'd' this is where the ink gets transferred from the recessed cells
to the substrate. The purpose of the Impression roller 'a' is to apply force,
pressing the substrate onto the Gravure cylinder 'd', ensuring even and
maximum coverage of the ink.
The capillary action of the substrate and the pressure from Impression rollers 'a'
force the ink out of the cell cavity and transfer it to the substrate. Then the
substrate goes through a dryer 3 because it must be completely dried before
going through the next color unit and absorbing another coat of ink.
Unprinted input is loaded in unwinding section 1 of the machine and after printing
printed substrate 5 and 'b' is winded in rewinding section 4 of the printing
machine.
II. REWINDING & TTO CODING PROCESS
As shown in Fig 2, the printed substrate (6) [Output of Step I. printing process]
with registered block preferably used on the unwinder (I) such that the inner of
the opaque intermediate substrate of the packaging laminate is exposed. The

above mentioned substrate is made to pass through Nip roller (8) different Idle
rollers (J) which use to guide and maintain tension of the substrate throughout
the path way. Alignment of the unwinder is controlled by edge guider (7).
Stroboscope (11) is fitted for easy defect detection, if any. The TTO coding
printer is to be positioned on the same side of the unwinder from which the
substrate passes to the Rewinder (l°). One Lay-On roller (12) is there to maintain
proper winding. The print head (10) of the TTO unit (9) activates after getting
signal from the Inspection machine and transfers melted ink from the thermal
transfer ribbon on the substrate. TTO Coded substrate (13) is winded in
Rewinder (l°).
Thermal Transfer Overprint Process (Ref. Figure no.- 2A)
The TTO printer as shown in Fig 2A is positioned on the Inspection/Rewinding
machine, such that the input substrate (16) passes under the TTO printer unit [by
rotating rollers - (17)]. While passing input substrate through TTO print head (19)
and over the top of a hard but pliable rubber surface (18) (known as a platen pad
or platen roller). During TTO coding, a signal is sent by a sensor (15) to the TTO
unit, the signal informs that the pre - selected non repeated code needs to be
printed. The print head lowers towards the substrate, intended to be coded. As
the print head lowers, it touches the TTO ribbon (14) and the TTO ribbon (14)
makes contact with the input substrate (16). Then print head, ribbon and the
substrate further lowers together and make contact with the hard rubber surface
(18) and this produces a pressure between the print head (19) and the rubber
surface (18). Once the pressure is generated between print head and the rubber
surface, the miniature elements in print head are activated/deactivated
sequentially, depending on the characters to be coded, which generates heat at
the print head (19). The heated elements produce enough heat to melt the dry
ink film (20) of the ribbon, turning the ink to liquid. The pressure of the print head,
coupled with the heating of the elements and the wetting of the ink, transfers
molten ink (21) from the ribbon to the input substrate and the required

code/image is coded on the substrate. Once the intended character is completely
coded, the print head returns to idle position inside the TTO unit (9 of Fig no. 2)
and waits for next signal to receive again.
The substrate may include one or more reverse coatings on the side of the
substrate opposite to that on which the structure appears. Reverse coatings may
be non-IR black or any other desired color inks that are preferably insensitive to
heating via infrared light. Such coatings may be conventional inks and may
include confusion patterns, game instructions or other information or indicia.
Structure, applied on the image side of substrate, preferably includes one or
more image layer, one or more obscuration layers, and one or more thermal
reactive layers. (The image and, if desired, reverse side of substrate may also
feature graphic images formed of conventional colored ink layers as desired.)
The structure may also include one or more overprint layers between the thermal
reactive layers and the obscuration layers, if desired, in order to provide a lighter
background for the thermal reactive layers.
The reverse coating or coatings and the color layers may be applied to the stock
before or after the sizing layer. These are applied by automated TTO printing
technology as a preferred embodiment.
III. LAMINATION PROCESS (REF. Figure No. - 3):
In Lamination process different layers are pasted together with the help of
adhesive and, and / or heat. The primary input layer (with TTO coding) is
preferably loaded in unwinder-1 (K), secondary input is loaded preferably in
unwinder-2 (L) and laminated output is winded in rewinder (K+L). The edge
guider (28) in unwinder-1 (K) section controls proper alignment of the unwinder
from which the TTO printed substrate (13 of Fig. No-2) is made to be passed
through the Adhesive coating cylinder (27) which is in contact with an adhesive
(24). On the other side transparent sealing substrate (29) from unwinder-2 (L) is
sandwiched with the adhesive coated substrate (26) by help of the Nip roller (25).
Sandwiched laminated output (30) is winded up in rewinder (K+L).

During passing from Unwinder-1 to rewinder adhesive coated primary input
substrate (26) passes through a hood (31) where sometimes heat may be
required depending on the requirement of lamination process.
In case of multilayer laminate where more than two substrates are there and the
layer/ layers subsequent to Gravure printed substrate are not transparent then
TTO coding to be done on the substrate which is immediately adjacent to
transparent sealant layer. In this case TTO coded laminate material to be loaded
to unwinder of Inspection/Rewinding machine (Ref. Fig.-2), before lamination
with transparent sealant layer.
IV. SLITTING: Coded laminate using TTO method is made to be slitted over a
cutting tool as per size required by customers. Final output is sent to dispatch
after packing.
Although the foregoing description of the present invention has been shown and
described with reference to particular embodiments and applications thereof, it
has been presented for purposes of illustration and description and is not
intended to be exhaustive or to limit the invention to the particular embodiments
and applications disclosed. It will be apparent to those having ordinary skill in the
art that a number of changes, modifications, variations, or alterations to the
invention as described herein may be made, none of which depart from the spirit
or scope of the present invention. The particular embodiments and applications
were chosen and described to provide the best illustration of the principles of the
invention and its practical application to thereby enable one of ordinary skill in the
art to utilize the invention in various embodiments and with various modifications
as are suited to the particular use contemplated. All such changes, modifications,
variations, and alterations should therefore be seen as being within the scope of
the present invention as determined by the appended claims when interpreted in
accordance with the breadth to which they are fairly, legally, and equitably
entitled.

Claims:
1. A method of printing of tamper proof unique codes in a packaging laminate
using thermal transfer overprinting (TTO) technology comprising steps of:
providing a primary printable substrate which is made to pass through
different printing stations to get printed in Gravure/Flexo printing machine;
feeding the said printed substrate on uniform aligned Unwinder of
Doctoring / Rewinding / Inspection machine through Nip roller and
different Idle rollers;
fitting the TTO coder on Unwinder or Rewinder side of Doctoring /
Rewinding / Inspection machine;
activating the TTO unit after getting signal from Rewinding machine Print
head for printing non repetitive unique codes, patterns on reverse side
registered block which is printed on primary substrate in Printing machine;
laminating the TTO coded substrate with a transparent intermediate
substrate;
wherein the unique non repetitive codes get sandwiched between the
substrate and;
wherein in case any opaque intermediate substrate present in laminate,
non-repetitive unique codes are made to be printed above on Rewinding
machine without/with registered block in printed substrate and get
laminated with a transparent substrate thereby making the codes abrasion
proof and tamper resistant.
2. A method of printing of tamper proof unique codes in a packaging
laminate as claimed in claim 1, wherein the Nip roller and different Idle rollers
(J) are used to guide, align and maintain tension of the substrate throughout
the path way.

3. A method of printing of tamper proof unique codes in a packaging
laminate as claimed in claiml, wherein the Thermal Transfer Overprint (TTO)
transfers the melted ink from the thermal transfer ribbon on the substrate.
4. A method of printing of tamper proof unique codes in a packaging
laminate as claimed in claim 2, wherein alignment of the unwinder is
controlled by edge guider.
5. A method of printing of tamper proof unique codes in a packaging
laminate as claimed in claiml, wherein any defect detection is carried out by
using Stroboscope .
6. A method of printing of tamper proof unique codes in a packaging
laminate as claimed in claiml, wherein the TTO coding printer is positioned
on the same side of the unwinder from which the substrate passes to the
rewinder.
7. A method of printing of tamper proof unique codes in a packaging
laminate as claimed in claiml, wherein proper winding / rewinding is
controlled by One Lay-On roller.
8. A method of printing of tamper proof unique codes in a packaging
laminate as claimed in claim 1, wherein during TTO coding, a signal is sent by
a sensor to the TTO unit, to locate the area of printing on substrate and the
signal informs that the pre - selected non repeated code needs to be printed.
9. A method of printing of tamper proof unique codes in a packaging
laminate as claimed in claim 1, wherein the TTO printed substrate is
preferably loaded in unwinder-1 (K), first printed substrate is loaded
preferably in unwinder-2 (L) and laminated output is winded in rewinder (K+L);
and

wherein the edge guider in unwinder-1 (K) section controls proper alignment
of the unwinder from which the TTO printed substrate is made to be passed
through the Adhesive coating cylinder which is in contact with an adhesive.
10.A method of printing of tamper proof unique codes in a packaging
laminate as claimed in claiml, further comprising the step of slitting wherein
the packaging laminate is made to be slitted in size.