Method of using an identification mark assigned to a document
The invention relates to a method of using an identification mark comprising a data
matrix, a bar code or the like assigned to a document for charging, payment,
validation and/or checking purposes and printed on the document or on a label that
can be applied thereto by means of thermal printing.
Methods of this kind are known and used, inter alia, for the digital franking of mail
items, in particular letters, parcels and the like. The envelope franked by a franking
system or a franking machine is provided with an identification mark comprising at
least one data matrix by a thermal printer, e.g. by thermal direct printing, thermal
transfer printing or thermal sublimation printing. These printing methods are
described in the relevant literature.
In the postal service, the identification data stored in a data matrix and printed on the
envelope or on the parcels, e.g. an MAC (message authentication code) or HMAC
(hash message authentication code), is secured and transmitted to a central server of
the franking system manufacturer. The letter is then sent on to a regional sorting
office. The conformance of the identification data on the envelopes is checked
electronically between the regional postal service and the central server of the
franking machine manufacturer before release so that it is possible to prevent, inter
alia, multiple or repeated use of the same postage stamp or mark or of the data matrix.
In Asian countries and in South American states, post offices, banks, law offices,
insurance companies and tax offices use what are referred to as tax meters for
collecting and charging fees and taxes of many different kinds, in particular for
deducting paid sums of money and issuing a corresponding receipt, e.g. by printing it
on a document or by applying a printed or preprinted label to the document,

By introducing a data matrix into the identification mark, governments and authorities
have incorporated an additional security element against unauthorised use, although it
is not produced by an algorithm suitable for drawing conclusions which could prevent
re-use, as the appropriate checking means are not available.
This method is being used increasingly in tax meters, although with the restriction that
the documents provided with the identification mark remain with the owner after the
payment of a charge, as a result of which re-use is not completely excluded.
Some tax offices have therefore been set up for a payment procedure in which the
customer pays his taxes or fees at a staffed counter and obtains an identification mark
printed on the voucher documenting the payment or on a label that can be applied
thereto confirming payment of the taxes. This printed identification mark can be
provided with an additional data matrix and is scanned at a Registration Office.
This prescribed official method of procedure and the equipment used therefor cannot
or does not provide any guarantee that the re-use or unauthorised use of the
identification mark issued as confirmation of or as a receipt for a payment made is
impossible, although the tax meters used are considered forgery-proof as the stamped
taxes or fees are stored in a tamper-proof security module and can be checked.
The individual amounts printed on the various documents by the tax meter are added
up by the tax meter and must correspond to the amount of money collected.
The original imprint on the document is moreover evidence of the fact that the
corresponding amount of money has been paid.
Although information technology in some countries of the world has not yet reached
the highest available state of the art, equipment allowing for the high-quality copying
of a contrasting ink can be found there, as a result of which differences between an
original identification mark and a mark copied or scanned therefrom are barely
discernible or readable.
The aim of this invention is to provide a method of the type mentioned at the outset
which stops the unauthorised use of copied or scanned identification marks as a result

of the possibility of confusion and prevents the possibility of deception by copying or
scanning.
The problem is solved according to the invention in that at least part of the print area
occupied by the identification mark is printed in at least one ink differing from the
remaining print area of the identification mark.
The areas are advantageously printed together in one operation so that the time
required therefor can be kept within limits.
Alternatively, the areas can be printed in two operations as a result of the differing
inks, the printing operations being carried out one after the other.
The areas preferably differ from one another by way of a visible or scannable ink and
an ink which cannot be read in the said manner, thereby making re-use by copying or
scanning much more difficult.
In the case of the identification mark containing a data matrix, a bar code or the like in
one of the areas, the area intended for the data matrix can be printed in an ink that
cannot be copied or scanned and that is not visible, thereby preventing complete
reproducibility.
It has proven to be advantageous for the remaining area of the identification mark
adjacent to the area comprising the code produced in black or dark blue contrasting
ink to be printed in a fluorescent ink. A printed image produced in a fluorescent ink
cannot be copied in identical form or in identical colours and the copy can be
distinguished from the original printed image in a relatively simple manner under
black light or ultraviolet light. A combination of a data matrix in a (common)
contrasting ink in one area and a fluorescent ink in another area provides additional
security against forgery, particularly in rural areas where collection points are not
equipped with a more modern IT infrastructure and may rely on or have to rely on
simpler checking with black light or ultraviolet light and fluorescent ink. Fluorescent
ink can be neither scanned, nor copied with colour fidelity. Comparison with an
original printed image will reveal at least a striking colour difference.

The method can preferably be carried out by a franking system or the identification
mark can be printed by a franking machine. A franking machine having a suitably
high-tech IT infrastructure improves efficiency and increases reliability and security
against forgery and unauthorised use.
One embodiment of the invention will now be described with reference to the cited
and citing prior art and to the drawings, to which reference should be made with
respect to all of the details not mentioned in the description. In the drawings:
Fig. 1 shows an identification mark printed by means of a tax meter and
Fig. 2 shows an identification mark printed according to the invention by a franking
machine.
Fig. 1 shows a known identification mark 1 printed on a document in a standard
contrasting ink by means of a tax meter and comprising the identification data and
information on the payment of taxes and fees required for its use as a voucher or
receipt or for (subsequent) checking. The identification mark 1 shown contains the
address (2) of the legal or natural person paying the required amount in rupees, the
national currency of India, "Rs. 0000000" (3). The identification mark 1 further
contains a licence number "012345678912" (4) assigned to the payer; the name of the
state "MAHARASHTRA" (5) for which payment is being made; the number of the
tax meter "FROOOOOO" (6) which printed the identification mark; the date and time of
the payment made printed by the tax meter "JUL 18 2009 08:15" (7); name of the
state in Hindi (8); type of form or voucher recorded "AGREEMENT" (9); amount
paid in words "ZERO ..." (10); serial number (not recorded) "54321" (11); country
"INDIA" (12); emblem for India (13); country in Hindi (14) and a data matrix 15.
The identification mark 1 distinguished according to the invention by at least two inks
is shown in Fig. 2. At least part 21, 22 of the print area occupied by the identification
mark 1 is printed in at least one ink differing from the adjacent remaining area 22, 21
by way of a visible contrasting ink, one of the areas 21, 22, as shown, being printed in
an ink that is not visible without aid, e.g. a fluorescent ink. The proportion of the total
print area of the identification mark 1 used for the area 21 and for the remaining area
22 is arbitrary.

Printing can be carried out in one ink or in a number of different inks and in one or
more operations accordingly, for which a franking system or a franking machine is
provided according to the invention. A suitable franking machine is described, e.g. in
WO 01/62503 A1 and WO 01/62504.
The identification mark 1 according to Fig. 2 has an area 21 printed in a contrasting
ink, e.g. black or dark blue, provided with general information and a data matrix 15.
The remaining area 22 comprises the special data and information of the identification
mark 1 which is not visible and cannot be copied or scanned, wherein this serves as
confirmation of payment and, e.g. can be read exclusively with an aid, such as a
fluorescent light, but, as already noted, cannot be copied. This special or protected
information, present in the area 22, may correspond to the content of the details found
in the data matrix 15 in Fig. 1.
The area 21 with the data matrix 15 can be printed in an ink that cannot be copied by
virtue of the method according to the invention.

WE CLAIM
1. Method of using an identification mark comprising a data matrix or a bar code
assigned to a document for charging, payment, validation and/or checking
purposes and printed on the document or on a label that can be applied thereto by
means of thermal printing, characterised in that at least part of the print area
occupied by the identification mark is printed in at least one ink differing from the
adjacent remaining area of the identification mark printed in a contrasting ink.
2. Method according to claim 1, characterised in that the areas are printed together
in one operation.
3. Method according to claim 1, characterised in that the areas are printed in at least
two operations.
4. Method according to claim 3, characterised in that the operations are carried out
one after the other.
5. Method according to one of claims 1 to 4, characterised in that the printed areas
differ from one another by way of a visible or scannable ink and a non-readable
ink.
6. Method according to claim 5, in which the data matrix or the bar code is arranged
in one of the areas of the identification mark, characterised in that the area
intended for the data matrix or the bar code is printed in the readable contrasting
ink and the adjacent remaining area is printed in an ink that cannot be copied or
scanned.
7. Method according to claim 6, characterised in that the area of the identification
mark adjacent to the area comprising the data matrix or the bar code is printed in
a fluorescent ink.
8. Method according to one of claims 1 to 7, characterised in that the identification
mark (1) is printed by a franking machine.

A method of using an identification mark comprising a data matrix or a bar code
assigned to a document for charging, payment, validation and/or checking purposes
and printed on the document or on a label that can be applied to a document by means
of thermal printing, consisting of at least part of the print area occupied by the
identification mark and printed in at least one ink differing from the adjacent
remaining area of the identification mark printed in a contrasting ink.