BACKGROUND OF THE INVENTION
[0001] Many documents.have monetary value. Some are even recognized to be privately issued
substitutes for money -- Traveler's Checks, money orders and stock certificates to
name but a few. Also, other documents have great value to show origin, titles, personal
identification, etc., motor vehicle certificates of origin, birth certificates and
Social Security cards are but a few examples.
[0002] The U.S. patent of Norris, et al., 3,985,927, issued October 12, 1976 discloses compositions
and a method for producing chemical watermarks in finished paper products, the watermarks
being produced by applying to the surface of the paper a chemical composition, which,
after suitable treatment to render its effect permanent replicates the appearance
of a conventional mechanical watermark, without detracting from the finishing, use
and keeping- quality of a document made from the paper. In contrast to printing, a
chemical watermark is colorless and cannot be dissolved from the paper. It is detected
primarily as a pattern of difference in translucence of the paper. The entire disclosure
of this patent of Norris, et al is incorporated herein by reference, inasmuch as it
further illuminates the state of the prior art, as well as teaches ways, means and
compositions for applying chemical watermarks to paper.
[0003] Other U.S. patents disclosing useful ways and means for synthetically watermarking
paper, using synthetic resins which, in contrast to those of Russell, do not require
application of ultraviolet light for curing, are shown and described in the following
U.S. patents, the entire disclosures of which are incorporated herein by reference:

[0004] The term "synthetic watermark" is used herein to denote a watermark which is produced
on paper mainly with the aid of a chemical process, in contrast to its being created
in the paper by mechanical means as a pattern of local thickness discontinuity during
manufacture of the paper from pulped fibers.
[0005] The term "serial number" is used herein to denote the unique string of indicia (characters)
which is applied to a document in order to distinguish that document, both from ones
that are otherwise identical but have applied indica series which differ as to at
least one indicium (character) and from ones which are not genuine. Use of the term
is not intended to imply that the string of indicia consists either partly or wholly
of numbers; in other words, a "serial number" as that term is used herein may include
any combination of numbers, letters, punctuation marks and specialized symbols. Falling
within this definition, in addition to conventional serial number, are amounts, names
and combinations thereof.
Summary of the Invention
[0006] A document security system is provided by providing each document with a synthetic
watermark, for instance using the process, compositions and apparatus disclosed in
the aforementioned U.S. patent of Norris, et al and, within the perimeter of at least
one of the symbols which is provided by the synthetic watermark, an identical complementary
or otherwise corresponding symbol is printed using ink, paint, dye, stain or similarly
contrastingly pigmented substance so as to create, in combination with the synthetic
watermark a juxtaposition that can be looked-for as evidence that the document is
genuine and its serial number unaltered.
[0007] In a preferred practice of the invention, both a synthetic watermark serial number
and a conventionally printed serial number are provided on each document in a set
of documents. Each document is thus made to be different from all of the others in
the set as well as from documents not in the set. In this preferred practice the synthetic
watermark serial number is the same as, but is applied in a larger typeface than the
conventionally printed serial number, with each character of the latter being centered
within the corresponding character of the former. As a result, when held to the light
a water mark "halo" appears around each of the conventionally printed characters,
thus complicating the task of replicating, photocopying or altering the document.
[0008] The principles of the invention will be further discussed with reference to the drawing
wherein a preferred embodiment is shown. The specifics illustrated in the drawing
is intended to exemplify, rather than limit, aspects of the invention as defined in
the claims.
Brief Description of the Drawing
[0009]
Figure 1 is a diagrammatic flow sheet illustrating successive steps in the practice
of preferred embodiment of the present invention; and
Figure 2 is a diagrammatic representation of an examination of a sample of the product
for. genuineness and lack of alteration.
Detailed Description
[0010] By way of example, in Figure 1, the process of the invention is shown being carried
out on a web of successive paper documents at a stage of document manufacture, the
web being conventionally advanced by engagement of tension pull rolls with the web.
(Preferably, the opposite marginal series of holes which may later be used for advancing
the web using conventional drive sprockets engaged therein are not formed in the web
until a later stage, although they could be provided earlier and used at this stage
for web advancement.)
[0011] In practicing the present invention in a preferred way, at a first station 10, a
sheet of paper 12 in a series of such sheets 14 is imprinted with a first string of
characters 16, of which at least one preferably is different for each successive sheet
in the series, so that the string of characters 16 imprinted on each sheet taken as
a whole string is unique and thus capable of functioning as a serial number of uniquely
identifying that particular sheet.
[0012] At this first station 10, the fluid material used for the imprinting is not like
an ink, in the sense that it does not use a solution or suspension of pigment applied
in a visible pattern which contrasts in color, chroma, hue or brilliance with the
paper substrate constituting the sheets 14.
[0013] Rather that fluid material is a composition which, when dried or cured, e.g. at a
subsequent curing station 18, which may include application of photons of a particular
band of energy levels and/or application of air drying with or without added heat,
causes the paper to sharply differ in degree of translucence where imprinted in comparison
with its degree of translucence where not so imprinted.
[0014] The pattern may either be one in which the imprinted characters, when a sheet of
the paper is viewed from the front with strong back-lighting, constitute a regional
pattern where the paper is more translucent than the non-imprinted remainder of the
sheet, or partly more translucent and partly less translucent.
[0015] 'The first string of characters 16 as illustrated in dashed lines in Figure 1, on
successive sheets typically may show-up under strong back lighting as a series of
successive segments e.g., which read, "...,
*6A,
*7A,
*8B,
*9B,
*OB,
*lB,...".
[0016] At a third station, 20,
. each sheet of paper is printed with a pigmented ink so that each bears a second string
of characters 22, illustrated in full lines, of which at least one preferably is different
for each successive sheet in the series, so that the string of characters 22 imprinted
on each sheet taken as a whole string is unique and thus capable of functioning as
a serial number for uniquely identifying that.particular sheet. Although it is preferred
that both strings of characters on each document be printed on the same line, the
principles of the invention can be practiced even if the two strings of characters
are provided on lines which adjoin one another or bear some other predetermined relationship.
[0017] By preference, at least one of the characters of the first string 16 applied and
developed as a synthetic watermark at stations 10, 18 is juxtaposed with at least
one of the characters of the second string 22 applied as a contrasting-color serial
number at station 20.
[0018] For instance the corresponding two characters may be alike and superimposed so that
one of them skirts the perimeter of the other about all of or a substantial part of
that perimeter.
[0019] In the instance depicted, the contrasting color-imprinted second series has a segment
which reads "...
*1 E,
*0 D,
*9 D,
*8 D,
*7 D,
*6 D...".
[0020] In this example, the typefont used for producing the synthetic watermark serial number
is similar to but larger-charactered than that used for producing the contrasting
color-imprinted serial number, so that if the.resulting documents D are held up to
the light, they are seen to be successively read "...
*1BE,
*OBD,
*9BD,
*8BD,
*7AD,
*6AD,...", in which the characters "
*" of the synthetic watermark-type first strings appear to halo 26 (border, permetrically
surround) like characters "
*" 28 imprinted with ink in the second series. In this example, the comparable situation
is true for the corresponding second character, A, in each of the two strings. However,
it is not true for the third character "...A, A, B, B, B, B...", which is present
only in the first strings 16, but not in the second string 22, where the corresponding
space is left non-imprinted, i.e. blank. Nor is it true for the fourth character position,
which in the first strings 16 is left blank, but in the second strings 22 is imprinted
with a character, e.g. "... E, D, D, D, D, D, E......
[0021] Thus, although the process and compositions and apparatus used for imprinting each
of the documents with each of its two strings of characters are known, the combination,
if performed in accordance with the principles of the present invention easily provides
a unique system for readily not only keeping track of the documents by serial number,
but also for conveniently examining them for lack of alteration, and for genuineness.
[0022] For instance, upon strongly back-lighting a document D (Figure 2), the examiner can
conveniently look for the fact that the "
*" in the first character position of the synthetic watermark "halos" the "
*" of the ink-printed serial number, for the fact that the "...1, 0, 9, 8, 7, 6,..."
in the second character position of the synthetic watermark "halos"-the respective
"...1, 0, 9, 8, 7, 6,..." in the second character position of the ink-printed serial
number, for the fact that the synthetic watermark character "..., B, B, B, B, A, A,..."
in the third character position corresponds to a no imprinted space in the third character
position of the ink-printed serial number, and for the fact that no synthetic watermark
character appears in the fourth position, where the ink imprinted serial number has
a character "...,E, D, D,
D,
D,
D,..
."
[0023] In looking at any one document D (Figure 2), the examiner can be looking for completeness
of the serial number (e.g. that it reads *6AD"),. the examiner can be looking for
lack of alteration of the serial number (e.g. that the "
*6" of the synthetic watermark both "halos" an "
*6" of the ink-imprinted serial number) and that the juxtaposition is characteristic
of a genuine one (e.g. that one
*6 is precisely centered on the other, that both are of the same type face and that
the halo extends one-half millimeter beyond the respective printed characters, this
example of juxtaposition and relative characteristics being only one among many which
could be adopted by the designer and issuer of the genuine documents D), and the examiner
can be looking for the side-by- side juxtaposition of synthetic and ink-imprinted
characters, rather than their juxtaposition (e.g. that no ink-imprinted character
appears in the third character position, but a synthetic watermark character does,
and vice versa as to the fourth character position, these being made as checks against
spurious addition or deletion of characters by a counterfeiter who is unwitting of
the code adopted for the serial number printing process).
[0024] Clearly, the examiner which performs the examination referred to in connection with
the above discussion can be but need not be a human, in that the system provided by
the invention lends itself easily to rapid and reliable routine examination of large
numbers of documents by light-sensitive electronic instruments, e.g. sets of photo-electric
cells in sensor circuits programmed to look for and distinguish presence and absence
of correspondence with characteristic features of the particular code adopted.
[0025] Registration systems used in printing processes are well-known and may be used in
a conventional manner for providing proper juxtaposition of the two strings of characters
on each document. Because these techniques are so well known in the trade, it is believed
unnecessary to describe them in further detail.
[0026] Various, conventional printing processes may be used for applying the two character
strings using presses which are sheet fed or web fed, and which apply the synthetic
watermark imprinting fluid of the first character string and the ink of the second
character string by stamping, rotary printing, felt printing, ink jet printing, ribbon-
impact printing or the like.
[0027] Likewise, the devices used for stepping- up the serial number from document to document
may be any convenient ones of such devices as are presently commercially available
for serial numbering of documents, e.g. ones in which the serial numbering is stepped
manually by rotating endless rubber mats of reverse characters as on a hand-operated
date-stamper, ones in which the serial number is automatically mechanically stepped
using a series of cams, pawls, ratchets and cam followers operating endless wheels
or bands of reverse characters, or ones in which serial number stepping is electronically
programmed, e.g. into the controller for a daisy wheel or ink-jet printer.
[0028] It should now be apparent that the document bearing characteristic ink-printed indicia
juxtaposed with corresponding characteristic synthetic watermark and method for producing
same as described hereinabove, possess each of the attributes set forth in the specification
under the heading "Summary of the Invention" hereinbefore. Because it can be modified
to some extent without departing from the principles thereof as they have been outlined
and explained in this specification, the present invention should be understood as
encompassing all such modifications as are within the scope and spirit of the following
claims.
1. A document printed on at least somewhat translucent paper and provided with identifying
characteristics, including:
a first string of characters provided as a synthetic watermark field in which the
relative translucence but not the color of the paper is contrasted, this string including
at least one character; and
a second string of characters provided as an ink-imprinted field in which the color
of the paper is contrasted, this string also including at least one character;
wherein at least one character in said synthetic watermark field is provided to have
a characteristic relative juxtaposition with at least one character in said ink-imprinted
field.
2. The document provided with identifying characteristics of claim 1, wherein:
said at least one character in said synthetic watermark field at least partially surrounds
a respective said at least one character in said ink-imprinted field.
3. The document provided with identifying characteristics of claim 2, wherein:
said at least one character in said synthetic watermark field which at least partially
surrounds said at least one character in said ink-imprinted field is a replication
of the same character, so that said at least one character in said ink-imprinted field
is haloed by said at least one character in said synthetic watermark field.
4. The document provided with identifying characteristics of claim 1, wherein:
said at least one character in said synthetic watermark field lies non-overlappingly
characteristically adjacent said at least one character in said ink-imprinted field.
5. The document provided with identifying characteristics of claim 4, wherein:
on each document said strings are provided in a line common to both of them.
6. The document provided with identifying characteristics of claim 5, wherein:
at least one of said at least one characters in at least one of said fields is provided
in a gap in the corresponding other of said fields.
7. A series of documents printed on paper, each being provided with a unique serial
number, which includes:
a first string of characters provided as a synthetic watermark field in which the
relative translucence but not the color of the paper is contrasted, this string including
at least one character; and
a second string of characters provided as an ink-imprinted field in which the color
of the paper is contrasted, this string also including at least one character;
wherein at least one character in said synthetic watermark field is provided to have
a characteristic relative juxtaposition with at least one character in said ink-imprinted
field.
8. The series of serially numbered documents of claim 7, in which:
said documents are severally connected in series as a web.
9. The series of serially numbered documents of claim 7, wherein:
said at least one character in said synthetic watermark field at least partially surrounds
a respective said at least one character in said ink-imprinted field.
10. The series of serially numbered documents of claim 9, wherein:
said at least one character in said synthetic watermark field which at least partially
surrounds said at least one character in said ink-imprinted field is a replication
of the same character, so that said at least one character in said ink-imprinted field
is haloed by said at least one character in said synthetic watermark field.
11. The series of serially numbered documents of claim 7, wherein:
said at least one character in said synthetic watermark field lies non-ovelappingly
characteristically adjacent said at least one character in said ink-imprinted field.
12. The series of serially numbered documents of claim 11, wherein:
on each document said strings are provided in a line common to both of them.
13. The series of serially numbered documents of claim 12, wherein:
at least one of said at least one characters in at least one of said fields is provided
in a gap in the corresponding other of said fields.
14. A method for providing each document in a series of paper documents with a serial
number, which includes:
printing on each document a first string of characters as a synthetic watermark field
in which relative translucence but not the color of the paper is contrasted; and
printing on each document a second string of characters as an ink-imprinted field
in which the color of the paper is contrasted, while
providing that at least one character in said synthetic watermark field has a characteristic
relative juxtaposition with at least one character in said ink-imprinted field.
15. The method of claim 14, wherein:
at least one said character in at least one said field is stepped in identity on successive
documents in said series.
16. The method of claim 15, wherein:
said at least one characteristically juxtaposted character in said synthetic watermark
field at least partially surrounds a respective said at least one characteristically
juxtaposed character in said ink-imprinted field.
17. The method of claim 16, wherein:
at least one respective said surrounded and surrounding juxtaposed character in said
fields is said at least one character which steps in identity on successive document
in said series.
18. The method of claim 16, wherein:
said at least one character in said synthetic watermark field which at least partially
surrounds said at least one character in said ink-imprinted field is a replication
of the same character, so that said at least one character in said ink-imprinted field
is haloed by said at least one character in said synthetic watermark field.
19. The method of claim 14, wherein:
said at least one character in said synthetic watermark field lies non-overlappingly
characteristically adjacent said at least one character in said ink-imprinted field.
20. The method of claim 19, wherein:
on each document said strings are provided in a line common to both of them.
21. The method of claim 20, wherein:
at least one of said at least one characters in at least one of said fields is provided
in a gap in the corresponding other of said fields.