Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
This invention relates to printed documents and to a
method of printing same.
With the advent of readily available copying machines
which can reproduce colors with fidelity, forging of checks and
the like has become a more serious problem since, if a forger can
gain access to a single blank check, he can readily make numerous
reproductions on such a copying machine with colored backing de-
tails faithfully reproduced.
An object of this invention is to provide a check which,
when copied on such a copying machine yields a copy which can read-
ily be distinguished from the original.
A further object of this invention is to provide a check
or the like which has portions which readily are copied by the
copying machine and other portions which are not reproduced
thereby.
Briefly, this invention provides a check or the like
having a background which is formed of dots of two different sizes
or diameters, the larger dots being of a size which can be repro-
duced by a copying machine, the smaller dots being of a size that
the copying machine cannot reproduce. A portion of the background
~ cf the check including wording for voiding the check can be formed
r ~` 30 of one size of dots while the remaining portion of the background
can be formed of the other size of dots. The dots in each portion
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1 can be arranged in groups separated by spaces so that both por-
tions can give a mottled effect. The number of the s~aller dots
per unit area can be sufficiently greater than the number of the
larger dots per unit area that both portions can gi~e a similar
effect and the portions appear to blend into each other. However,
if a copy is made, only the larger dots are reproduced so that
the portion having the smaller dots appears blank in the copy.
The above and other o~jects and features of the invention
will be apparent to those skilled in the art to which this inven-
tion pertains from the following detailed description and thedrawings, in which:
Fig. 1 is a plan view of a check constructed in accord-
ance with an embodiment of this invention;
Fig. 2 is a plan view of a cop~ of the check illustrated
in Fig. l;
Fig. 3 is a fragmentary plan view on an enlarged scale
of a portion of the check, the portion being indicated by dot-
dash lines in Fig. l;
Fig. 4 is a plan view of a mask used in forming a plate
from which the check is printed;
Fig. 5 is a fragmentary plan view on an enlarged scale
; of a portion of a mezzotint mask used in forming the plate;
Fig. 6 is a fragmentary plan view on an enlarged scale
of a patterned mask used in forming the plate;
Fig. 7 is a fragmentary view in side elevation showing
a first stack of elements used in forming the plate;
Fig. 8 is a fragmentary view in side elevation of a
second stack of elements used in forming the plate; and
Fig. 9 is a frag~lentary view in side elevation of a
third stack of elements used in forming the plate.
In the following detailed description and the drawings,
like reference characters indicate like parts.
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1 In Fig. 1 is shown a check 16 which can carry standard
indicia 18 and which is provided with a printed background 26 in
a se~lected color. The background 20 is made up of large dots 22
(Fig. 3) and small dots 24 arranged in a pattern on the face of
the check. A border line 25 (Figs. 1 and 2) can extend around a
selected portion of the periphery of the background. The large
dots 22 (Fig. 3) can be of a size which is readil~ reproduced by
a color copying machine, such as the machine known as a Xerox 6500, ;
a trademark of Xerox Corporation. The small dots 24 can be suf-
ficiently small in diameter that such a machine cannot reproduce
them. The showing in Fig. 3 is enlarged so that the diameter of
each of the dots is shown approximately 8 times the actual diam-
eter. Each of the large dots can be approximately 1/100 inch in
diameter. Each of the smaller dots can be approximately 1~200
inch in diameter.
The pattern of the dots can be such that, when a copy of
the check is made and only the large dots are reproduced, a copy
is formed as shown at 26 in Fig. 2 in which indicia 28 is formed
on the face of the check copy to invalidate the copy. The indicia
28 represents the portion of the background in small dots. The
indicia appears unprinted in the copy whereas, in the check 16
(Fig. 1), all the background can give a substantially continuous
and uniform appearance to the naked eye, and there is a sufficient
concentration of small dots in the indicia portion to give the
same effect to the human eye as the large dots in the background
portion surrounding the indicia.
A plate for printing the background for the check can be
formed photographically. The plate is prepared in a series of
stages or steps.
In the first step in a preferred method of preparing the
printing plate, a photosensitized plate 30 (Fig. 7) is assembled
with a mask 32, which carries a positive of the indicia, a screen
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1 34, which can form the large dots, and a mask 36, which provides
an :irregular textured or mezzotint pattern. The screen 34 can be
a sl;andard 85 line 30 percent screen. The mask 36 can have an
irregular pattern as shown at 38 in Fig, 5. In Fig. 5, the design
is shown on the same enlarged scale (8 diameters) as in Fig. 3.
q~he mask 36 can be formed as a negative of a standard heavy mezzo-
tint design such as that known as CHARTPAK Cat. No~ PT009, a trade- ;
mark of Chart-Pak, Incorporated. The plate is exposed in this
first assembly.
In a second step of the preferred method (Fig. 8), the
sensitized plate 30 is assembled with a mask 40, which can be a
negative of the mask 32, a screen 42 which can form the small dots,
and the mezzotint mask 36. The screen 42 can be a standard 150
line 15 percent screen. The relationship between the plate 30
and the mezzotint mask 36 in step 2 can be the same as in the
first step. The indicia on the negative mask 40 can be in the
same position relative to the plate 30 in the second step as the
indicia of the mask 32 in the first step. The plate is exposed
in this second assembly.
In a third step of the preferred method, the sensitized
plate 30 is assembled with the mask 40, the screen 42, and a pat-
terned mask 44. The relationship between the plate 30, the mask
40, and the screen 42 can be the same in the third step as in the
second step. The mask 44 can have the pattern shown in Fig. 6 at
46. In Fig. 6, the design is shown on the same enlarged scale
(8 diameters) as the showing in Fig. 3. The pattern is selected
to add sufficient small dots to those already on the plate so that
the concentration of small dots is sufficient to give the same
effect to the human eye in the indicia portions as is provided by
the large dots in the other portions of the background, The mask
44 can be a negative of a commercial design known as FOR~TT No~
7115, a trademark of Graphic Products, Corporation. The plate is
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1 exposed in this third assembly.
After having been exposed, the plate is developed in the
usual way and is used for printing the background of checks in
the usual fashion.
The check is shown with the indicia portion of the back-
ground in small dots and the remaining portion of the background
in large dots. However, the indicia portion of the background
can be printed in large dots and the remaining portion of the
background can be printed in small dots.
The pattern of the document background is subject to
variation within the scope of the appended claims.
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