U.S. patent application number 14/304936 was filed with the patent office on 2015-11-26 for overprinting system and method.
The applicant listed for this patent is Kobi BAR, Eli GRINBERG. Invention is credited to Kobi BAR, Eli GRINBERG.
Application Number | 20150339545 14/304936 |
Document ID | / |
Family ID | 54434623 |
Filed Date | 2015-11-26 |
United States Patent
Application |
20150339545 |
Kind Code |
A1 |
GRINBERG; Eli ; et
al. |
November 26, 2015 |
OVERPRINTING SYSTEM AND METHOD
Abstract
A method of adaptive overprinting of a first digital image over
a pre-printed second image comprising at least one feature, the
method comprising: capturing an image of a substrate pre-printed
with said second image and with at least one registration mark;
automatically computing: one or more offsets from intended
pre-determined properties of the at least one registration mark;
and one or more compensation adjustment values to be applied to
properties of the at least one feature, based on said one or more
computed offsets; applying said computed one or more compensation
adjustment values to said first digital image to create a corrected
digital image; and printing said corrected digital image over said
second image.
Inventors: |
GRINBERG; Eli; (Pardesia,
IL) ; BAR; Kobi; (Kfar Saba, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GRINBERG; Eli
BAR; Kobi |
Pardesia
Kfar Saba |
|
IL
IL |
|
|
Family ID: |
54434623 |
Appl. No.: |
14/304936 |
Filed: |
June 15, 2014 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
12682163 |
May 16, 2011 |
|
|
|
14304936 |
|
|
|
|
Current U.S.
Class: |
358/1.5 |
Current CPC
Class: |
G06K 2215/101 20130101;
G06K 15/1889 20130101; G06F 3/12 20130101; G06K 15/027 20130101;
G06K 15/186 20130101; G06K 15/021 20130101; G06K 15/105 20130101;
G06K 2215/111 20130101 |
International
Class: |
G06K 15/02 20060101
G06K015/02; G06K 15/10 20060101 G06K015/10 |
Claims
1. A method of adaptive overprinting of a first digital image over
a pre-printed second image comprising at least one feature, the
method comprising: capturing an image of a substrate pre-printed
with said second image and with at least one registration mark;
automatically computing one or more global offsets from intended
pre-determined properties of the at least one registration mark;
automatically computing one or more global compensation adjustment
values to be applied to the at least one feature, based on said one
or more computed global offsets; applying, by a processor using
image processing, said computed one or more global compensation
adjustment values to said first digital image to create a corrected
digital image; and printing said corrected digital image over said
second image.
2. The method of claim 1, wherein said global offset comprises at
least one of a global spatial shifts, a global intensity shift and
a global color shift.
3. The method of claim 2, wherein said global spatial shifts
comprise at least one of a global rotational shift and a global
size shift.
4. The method of claim 1, further comprising: automatically
computing one or more local offsets from intended pre-determined
properties of the at least one feature; automatically computing one
or more local compensation adjustment values to be applied to the
at least one feature, based on said one or more computed local
offsets; and applying, by a processor using image processing, said
computed one or more local compensation adjustment values to said
first digital image to create a corrected digital image.
5. The method of claim 4, wherein said local offset comprises one
or more missing parts of said at least one feature.
6. The method of claim 4, wherein said local offset comprises one
or more shifted parts of said at least one feature.
7. The method of claim 4, wherein said local offset comprises at
least one of a local intensity shift and a local color shift.
8. The method of claim 1, further comprising: recording in a log
identification information associated with the substrate when the
one or more determined offsets have values indicative that the
substrate requires shift adaptive overprint intervention.
9. A system for adaptive overprinting of a first digital image over
a pre-printed second image comprising at least one feature, the
system comprising: an imager configured to capture an image of a
substrate pre-printed with said second image and with at least one
registration mark; a processor configured to: automatically compute
one or more global offsets from intended properties of the at least
one registration mark pre-printed on the substrate, based on the
captured image of the substrate; automatically compute one or more
global compensation adjustment values to be applied to the at least
one feature, based on said computed global offsets; and apply,
using image processing, said computed one or more global
compensation adjustment values to said first digital image to
create a corrected digital image; and a printer configured to print
said corrected digital image over said second image.
10. The system of claim 9, wherein said global offset comprises at
least one of a global spatial shift, a global intensity shift and a
global color shift.
11. The system of claim 10, wherein said global spatial shifts
comprise at least one of a global rotational shift and a global
size shift.
12. The system of claim 9, wherein said processor is further
configured to: automatically compute one or more local offsets from
intended pre-determined properties of the at least one feature;
automatically compute one or more local compensation adjustment
values to be applied to the at least one feature, based on said one
or more computed local offsets; and apply using image processing,
said computed one or more local compensation adjustment values to
said first digital image to create a corrected digital image.
13. The system of claim 12, wherein said local offset comprises one
or more missing parts of said at least one feature.
14. The system of claim 12, wherein said local offset comprises one
or more shifted parts of said at least one feature.
15. The system of claim 12, wherein said local offset comprises at
least one of a local intensity shift and a local color shift.
16. The method of claim 1, wherein said substrate is a single
page.
17. The method of claim 1, wherein said substrate is part of a
roll.
18. The system of claim 9, wherein said substrate is a single
page.
19. The system of claim 9, wherein said substrate is part of a
roll.
20. The method of claim 1, wherein said printing comprises printing
with one of: varnish, colors, security inks and conductive inks.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to overprinting, and more
particularly to adaptive corrected overprinting.
BACKGROUND OF THE INVENTION
[0002] Overprinting is the intentional printing of one or more
layers of ink, or other such printing media, on top of another, for
example by coating or varnishing. In this manner, a previously
printed media can be enhanced, for example, with a glossy finish.
The overprint or overcoat can be on the entire media or substrate,
on one or more features previously printed on the substrate or be
printing printed adjacent to previously printed features, or any
combination of these.
[0003] To print on specific features and produce a high quality
overprint, it is critical that the overprint ink be accurately
applied on the substrate. For this purpose, the overprint coating
applicator, for example, an ink-jet nozzle, must be accurately
aligned with the features to be coated.
[0004] Another example of overprinting one in which a symbol or
text, etc, is printed after a first printing, and the overprinting
is printed adjacent or in proximity to, but not necessarily
directly over, the symbol or text.
[0005] U.S. Pat. No. 4,857,715 (Koch et al) discloses a scannable
form for an optical mark scanning apparatus in the form of a
generally rectangular sheet of paper or like material having a
preprinted timing track along one edge and a plurality of
preprinted quality assurance marks is printed by a laser printer
with customized questions and corresponding response bubbles to
create a survey form. An overprint registration system is used in
conjunction with the scannable forms to align material for printing
on the scannable forms prior to printing the survey form by
printing an overprint registration mark corresponding to at least
one of the quality assurance marks and adjusting the position of
the overprint registration mark to establish the alignment between
the response bubbles to be printed and the preprinted timing track.
The system may also include a verification process wherein a
plurality of alignment marks will be overprinted in the position of
the overprint registration marks during the printing of the survey
form, so that the alignment of each form in relation to the quality
assurance marks may be verified during scanning.
[0006] U.S. Pat. No. 5,600,350 (Cobbs et al) describes an image
registration system for a multicolor inkjet printer/plotter. The
system comprises a carriage assembly for retaining multiple inkjet
cartridges. Each cartridge has a plurality of nozzles adapted to
eject ink in response to the application of an electrical signal
thereto. A first mechanism is provided for moving the carriage
assembly means in a first axis. A second mechanism is provided for
moving print media in a second axis transverse to the first axis,
the first axis being a scan axis and the second axis being a media
axis. A first position encoder senses the position of the carriage
assembly in the first axis and a second position encoder senses the
carriage assembly in the second axis and providing position encoder
signals in response thereto. A control circuit provides electrical
signals which cause the nozzles in the inkjet cartridges to eject
ink onto the media and create an image thereon in response to
timing signals. The system includes a sensor module which optically
senses the image and provides a set of sensed signals in response
thereto. The sensed signals are processed to provide timing signals
for use in correcting the image miss-registration.
[0007] U.S. Pat. No. 6,454,383 (Lund et al) provides a method and
apparatus for a test pattern used in the alignment of an ink-jet
pen which deposits fixer fluid, or other clear ink precursor fluid,
on print media uses the change in reflectivity caused by
overprinting a series of positional-calibration indicia with
colorant to obtain data with respect to deviations in a
carriage-scan x-axis and a paper scan y-axis. Thus the invention
measures distances between pens or nozzles.
[0008] U.S. Pat. No. 5,803,504 (Deshiens et al) describes a method
of producing a lottery ticket with an overprint region provided
over a scratch-off layer. To ensure proper alignment of printing
layers of the overprint region, photocell devices are installed at
each of the stations of press maybe linked to various controls of
the paper feeding mechanism of the press. Preferably, the
registration devices in the flexographic press should allow no more
than a 0.005 inch (0.013 cm) variation on each station.
[0009] U.S. Pat. No. 6,840,173 (Kawabata et al) discloses a plate
cylinder and printing plate holder for the cylinder, which is
capable of adjusting relative positions of plural printing plate
holders and fixing the printing plate holders on the plate cylinder
without causing misalignments of images among printing plates held
by the printing plate holders even after overprinting. The plate
cylinder is equipped with at least two printing plates wrapped
around the outer circumference thereof. The plate cylinder
comprises printing plate holders, one per each printing plate, for
holding the printing plates on the outer circumference of the plate
cylinder. The printing plate holders include one printing plate
holder in a stationary state and fixed against the plate cylinder
and other printing plate holders that are adjustable to move in the
circumferential direction of the plate cylinder and fixable against
the plate cylinder.
[0010] U.S. Pat. No. 5,434,956 (Myungsea son et al) discloses a
method and apparatus for printing an image in a specified
positional relationship with a preprinted registration mark. Each
two-dimensional alignment mark on a printing medium is found by
using information about the whole mark area, or with respect to
each of two different directions relative to the medium by using a
distinctive two-dimensional pattern or characteristic of the mark;
or by finding the mark centroid, or by scanning the mark region to
obtain a two-dimensional representation for analysis--and
preferably by combinations of these procedures. An image is then
aligned and printed by reference to the mark so located. A previous
image may also be preprinted in known relation with the mark, so
that the new image is aligned with the preprinted one--sometimes on
the same piece of medium. Preferably information used includes the
mark's intended size, shape, areal disposition and other
properties; and a two-dimensional search template is defined which
matches the mark in at least one of these. A template position is
then found that essentially maximizes areal intersection with the
mark; this position is then treated as the mark position, for
printing the new image. The invention preferably determines a
position of the template along each of two directions in
alternation--maximizing the areal intersection with respect to
shifting along each direction, iteratively--until no significant
increase is obtained.
[0011] U.S. Pat. No. 6,325,480 (Moghadam et al) discloses an inkjet
printer and method capable of forming a plurality of registration
marks on a receiver and sensing the marks formed thereby. The
method includes a print head for printing an image of predetermined
length on the receiver. The receiver has an image area for
receiving the image therein and a border area adjacent to the image
area. A marker forms the plurality of registration marks in the
border area, so that the marks extend the length of the image. In
addition, a sensor is disposed in sensing relationship to the marks
for sensing the marks. The invention provides a combination marker
for marking a receiver and a sensor for sensing the marks so that
each image line is in registration with other lines of the image.
Also, use of the invention avoids need for costly precision motors
to advance the receiver during printing of image lines.
[0012] To aid in applying the overprint coating accurately, prior
art relies on registration markers, typically in the form of cross
hairs, located in two corners of the substrate. However, during the
pre-overprinting print, registration markers and the specific
features may be misaligned; i.e. moved from their intended location
in an x-direction, and/or a y-direction, and/or at an angle, and/or
due to scaling (enlargement/reduction) and so on. Other types of
misalignment can also be present, as will be discussed in more
detail below.
[0013] It is therefore a long felt need to disclose a means and
method for overprinting that overcomes the difficulty of
identifying a misalignment between registration markers and
preprinted features, such that the overprint is not aligned in
accordance with said registration markers, but rather in accordance
with said pre-printed features. Moreover, it is a long felt need to
address a plurality of printing shifts beyond misalignment, namely
global shift, a local shift, a linear shift, an angular shift, a
size shift, an intensity shift, a color shift, or any combination
thereof.
[0014] It is also a long felt need to compensate for the
misalignment and shifts using image processing rather than by
mechanical means (a set of signals to the printer), thus enabling
to address any printer suitable for the task.
SUMMARY OF THE INVENTION
[0015] According to a first aspect of the present invention there
is provided a method of adaptive overprinting of a first digital
image over a pre-printed second image comprising at least one
feature, the method comprising: capturing an image of a substrate
pre-printed with said second image and with at least one
registration mark; automatically computing one or more global
offsets from intended pre-determined properties of the at least one
registration mark; automatically computing one or more global
compensation adjustment values to be applied to the at least one
feature, based on said one or more computed global offsets;
applying said computed one or more global compensation adjustment
values to said first digital image to create a corrected digital
image; and printing said corrected digital image over said second
image.
[0016] The global offset may comprise at least one of a global
spatial shifts, a global intensity shift and a global color
shift.
[0017] The global spatial shifts may comprise at least one of a
global rotational shift and a global size shift.
[0018] The method may further comprise: automatically computing one
or more local offsets from intended pre-determined properties of
the at least one feature; automatically computing one or more local
compensation adjustment values to be applied to the at least one
feature, based on said one or more computed local offsets; and
applying said computed one or more local compensation adjustment
values to said first digital image to create a corrected digital
image.
[0019] The local offset may comprise one or more missing parts of
said at least one feature.
[0020] The local offset may comprise one or more shifted parts of
said at least one feature.
[0021] The local offset may comprise at least one of a local
intensity shift and a local color shift.
[0022] The method may further comprise: recording in a log
identification information associated with the substrate when the
one or more determined offsets have values indicative that the
substrate requires shift adaptive overprint intervention.
[0023] According to a second aspect of the present invention there
is provided a system for adaptive overprinting of a first digital
image over a pre-printed second image comprising at least one
feature, the system comprising: an imager configured to capture an
image of a substrate pre-printed with said second image and with at
least one registration mark; a processor configured to:
automatically compute one or more global offsets from intended
properties of the at least one registration mark pre-printed on the
substrate, based on the captured image of the substrate;
automatically compute one or more global compensation adjustment
values to be applied to the at least one feature, based on said
computed global offsets; and apply said computed one or more global
compensation adjustment values to said first digital image to
create a corrected digital image; and a printer configured to print
said corrected digital image over said second image.
[0024] The global offset may comprise at least one of a global
spatial shift, a global intensity shift and a global color
shift.
[0025] The global spatial shifts may comprise at least one of a
global rotational shift and a global size shift.
[0026] The processor may further be configured to: automatically
compute one or more local offsets from intended pre-determined
properties of the at least one feature; automatically compute one
or more local compensation adjustment values to be applied to the
at least one feature, based on said one or more computed local
offsets; and apply said computed one or more local compensation
adjustment values to said first digital image to create a corrected
digital image.
[0027] The local offset may comprise one or more missing parts of
said at least one feature.
[0028] The local offset may comprise one or more shifted parts of
said at least one feature.
[0029] The local offset may comprise at least one of a local
intensity shift and a local color shift.
[0030] The substrate may be a single page.
[0031] The substrate may be part of a roll.
[0032] The printing may be done by printing with one of: varnish,
colors, security inks and conductive inks.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] The invention may be more clearly understood upon reading of
the following detailed description of non-limiting exemplary
embodiments thereof, with reference to the following drawings, in
which:
[0034] FIG. 1 is a perspective view of an embodiment of a printing
system for overprinting on a substrate of the present
invention;
[0035] FIG. 2 is an elevated view of a substrate having a feature
disposed in its designed location (with no offset);
[0036] FIGS. 3A-3H are elevated views of substrates with exemplary
offsets that can accurately overprinted by the printing system of
the present invention;
[0037] FIG. 4 is a flowchart depicting an embodiment of a method of
the present invention; and
[0038] FIG. 5 is a flowchart depicting another embodiment of a
method of the present invention.
DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0039] The following description is provided, alongside all
chapters of the present invention, so as to enable any person
skilled in the art to make use of said invention and sets forth the
best modes contemplated by the inventor of carrying out this
invention. Various modifications, however, will remain apparent to
those skilled in the art, since the generic principles of the
present invention have been defined specifically to provide a means
and method for adaptive overprinting.
[0040] The term `handling device` refers hereinafter to the devices
or mechanisms for feeding a substrate into a printing device, for
holding the substrate during printing and for expelling the
substrate after printing.
[0041] The term `plurality` refers hereinafter to any integer
number equal or higher than one, e.g., 2, 3, 4, etc.
[0042] The terms `shift` or `printing shift` are used
interchangeably hereinafter in the broadest manner including a
longitudinal and/or lateral disposition (i.e. x-y or Cartesian
coordinate skew; also know as a linear shift); an angular shift or
disposition (i.e. polar coordinate type); a size shift (e.g. due to
an enlargement or size reduction anomaly of any or all features or
portion(s) thereof); a local shift (i.e. wherein only one or
some--or portions thereof--of features contain anomalies or
deviations; an intensity shift (i.e. the intensity or boldness or
portion thereof deviates from the designed intensity a color shift
wherein the color or shade of a feature(s) appearing on the
substrate are not as intended (e.g. fading due to age or sun
exposure, dirt, chemicals, etc) or the color shift is used to
determine a proper color for matching a color to be printed
adjacent to the feature(s). Aside from the local shifts, the
aforementioned shift types may be categorized as "global shifts" if
the feature(s) are affected (shifted, etc.) in an analogous manner
to the registration markers.
[0043] The aforementioned meanings and explanations of the
interchangeable terms misalignment, skew and shift should become
clearer upon reading of the detailed description.
[0044] The term `substrate` is used in its broadest meaning and
includes any medium that can be printed upon, for example, paper,
plastic, wood, metal, films and so on.
[0045] The `pre-printed feature` refers hereinafter to any image or
markings that have been stamped upon a substrate prior to being
introduced to the overprint system.
[0046] Advantages of the overprinting system and method of the
present invention include: [0047] 1. It does not require set up and
does not require plates, screens or pre-press preparation. [0048]
2. It can be used for flood coating or spot coating, e.g. a UV spot
coating. [0049] 3. It is conveniently used with most common paper
sizes in the conventional and digital printing industry. [0050] 4.
The coating is determined directly from a computer file.
[0051] FIG. 1 shows an embodiment of an overprinting system of the
present invention for printing on a substrate 10, for example a
sheet of paper and the like. The substrate 10 has a pair of
registration markers 12a and 12b, typically in the form of cross
hairs, located for example in two corners thereof. The substrate 10
further comprises a feature 14 from a previous printing thereon,
shown as a square for demonstration purposes only. The feature 14
or parts thereof are designed to be overprinted by the overprinting
system or to serve as a reference point for overprinting.
[0052] The system of the present invention comprises a paper feeder
16, a platform 18 for receiving the substrate 10, an imaging device
or imager 20, an overprinting mechanism 22, a control module or
controller 24, shown housed in a housing or cabinet 26 and a
processor 25 configured to perform image processing. The controller
24 is operationally connected to the imager 20 and to the
overprinting mechanism 22.
[0053] The system also comprises a device (not shown) for moving
the paper 10 from the platform 18 where overprinting occurs to any
following stage, for example, exposure to UV radiation to dry the
overprinting ink, in the case of a UV spot coating. Such following
stage is represented schematically by tray 28.
[0054] In accordance with particular embodiments, the overprinting
mechanism 22 comprises a printing head such as an ink-jet nozzle 30
or a plurality thereof (only one shown), and a mechanism for
holding and moving the ink-jet nozzle such as a moveable bar 32.
The overprinting mechanism 22 may be designed to move the ink jet
nozzle 30 in both the x-direction and y-direction, for example by
moving the ink jet nozzle 30 along the bar 32 (e.g. in the
x-direction) and moving the bar (e.g. in the y-direction) over the
substrate 10 when it resides on the platform 18. It should be
understood that other printing mechanisms may be used, for example,
a laser printing mechanism (not shown).
[0055] The imager 20 is typically an optical imager whose function
and mechanism can constituted by a variety of means, for example it
may be housed in the bar 32 and scan the substrate 10. Likewise, it
should be understood that other ink-jet nozzle movement options can
be devised, one example being wherein the substrate 10 is moved in
one or both of the x-direction and/or y-direction--or in
combination with the overprinting mechanism 22.
[0056] In another embodiment of the present invention, the paper
feeder 16 may be replaced by a roll to roll feeding method or by
any feeding method known in the art.
[0057] In the present invention, a plurality of registration marks
may be applied. The greater the number of registration markers the
greater the degree of accuracy that may be achieved in aligning the
overprint to the pre-printed image on the substrate. For
explanation purposes the description hereinafter refers to a pair
of markers but it is understood that the scope of the invention is
not limited to these specific examples.
[0058] In cases of a distortion offset, a rotation offset and the
like the correction will be better and more accurate with a
plurality of markers. The higher the number of registration marks,
the better the compensation may be. As will be described below, the
compensation may be done by the processor using image processing by
manipulating the overprinting file and when needed, manipulating
the digitized image of the master substrate as well as will be
explained below. Thus the printing and/or the overprinting may be
done with any printer suitable for the task, independent of the
specific printer, since the compensation is done on the image and
not by controlling the printer movements.
[0059] FIG. 2 shows the substrate 10 with its registration markers
12a and 12b in their intended locations. These registration markers
12a and 12b are standard commercially utilized markers. For
explanation purposes, the feature 14 is shown a distance of "D"
units in the x-direction from the registration marker 12a center
and a distance of "S" units in the y-direction from that marker.
However, due to offset(s), the registration markers 12a and 12b may
not be in their intended locations.
[0060] FIG. 3A shows a first example of a possible offset wherein
the registration markers 12a and 12b are not in their intended
locations. In this example, the registration markers 12a and 12b
are shifted or translated a distance "d" in the x-direction from
those intended locations. For explanation purposes, the shifted
registration marks are shown using dashed lines and their actual
positions are designated 13a and 13b, respectively. These reference
numerals will be used throughout in regard to global positional and
size offsets (as compared to local offsets, intensity offsets and
color offsets, which will be discussed below).
[0061] Prior to applying the overprint, the imager 20 images the
substrate 10 or parts thereof and thereby determines and quantifies
the aforementioned shift, i.e. the actual locations 13a and 13b of
the registration markers 12a and 12b and that the shift is "d"
units in the x-direction. The feature 14 is therefore determined to
be shifted "d" units in the x-direction from its intended location.
This information is conveyed to the controller 24 which in turn
actuates and controls the overprinting mechanism 22 to compensate
for this offset. Thus an accurate overprinting over or in relation
to feature 14 can be performed.
[0062] Alternatively, the compensation process may be done by the
processor using image processing, namely, by manipulating the
overprinting file according to the x-direction offset. Then,
printing the manipulated file over or in relation to feature 14.
Thus an accurate overprinting can be performed.
[0063] FIG. 3B shows another example of a possible offset wherein
the registration markers 12a and 12b are not in their intended
locations. In this example, the registration markers 12a and 12b
are shifted or translated a distance "d1" in the y-direction from
those intended locations.
[0064] In a similar manner as described with reference to FIG. 3A,
prior to applying the overprint, the imager 20 images the substrate
10 or parts thereof and thereby determines and quantifies the
aforementioned shift, i.e. the actual locations 13a and 13b of the
registration markers 12a and 12b and that the shift is "d1" units
in the y-direction. The feature 14 is therefore determined to be
shifted "d1" units in the y-direction from its intended location.
This information is conveyed to the controller 24 which in turn
actuates and controls the overprinting mechanism 22 to compensate
for this offset.
[0065] Alternatively, the compensation process may be done by the
processor using image processing, namely, by manipulating the
overprinting file according to the y-direction offset. Then,
printing the manipulated file over or in relation to feature 14.
Thus an accurate overprinting can be performed.
[0066] FIG. 3C shows yet another example of a possible offset
wherein the registration markers 12a and 12b are not in their
intended locations. In this example, the registration markers 12a
and 12b are turned or angled at an angle "theta". For convenience
of displaying this offset, the actual positions 13a and 13b will be
displayed as having an x-direction offset as well (however, the
feature 14 is not shifted). It should be understood that any and
all combinations of offsets, those already described, those yet to
be described, and those not described herein but falling within the
scope of the claimed invention, can occur separately or in
combination.
[0067] Again, prior to applying the overprint, the imager 20 images
the substrate 10 or parts thereof and thereby determines and
quantifies the aforementioned shift, i.e. the actual locations 13a
and 13b of the registration markers 12a and 12b and that the offset
is an angle "theta" (and any x-direction and/or y-direction units
shift). This information is conveyed to the controller 24 which in
turn actuates and controls the overprinting mechanism 22 so that an
accurate overprinting over feature 14 can be produced.
Alternatively, the compensation process may be done by the
processor sing image processing, namely, by manipulating the
overprinting file according to the rotation angle. Then, printing
the manipulated file over or in relation to feature 14. Thus an
accurate overprinting can be performed.
[0068] FIG. 3D shows still another example of a possible offset,
which will be termed a size offset. Here, the actual (imaged) size
of the markers 13a and 13b is different than the intended size of
the markers 12a and 12b. Consequently, the feature 14 may appear
somewhat enlarged or reduced in size versus the intended size. In
FIG. 3D, an enlargement offset is exemplified. For visualization
purposes only, the actual positions 13a and 13b (indicating an
enlargement in this example) will be displayed as having an
x-direction offset as well. It can be noticed that the feature 14
is enlarged in proportion to the enlargement of the registration
markers 12a and 12b in their actual sizes 13a and 13b.
[0069] Once again, prior to applying the overprint, the imager 20
images the substrate 10 or parts thereof and thereby determines and
quantifies the aforementioned enlargement, and there is a
compensating effect applied by the overprinting system for this
offset.
[0070] The compensation process may be done by the processor in
image processing, namely, by manipulating the overprinting file
according to the scaling factor. Then, printing the manipulated
file over or in relation to feature 14. Thus an accurate
overprinting can be performed.
[0071] FIG. 3E shows another example of a possible offset, which
will be termed an intensity offset. Here, the intensity of the
markers 13a and 13b, may be different than the intended intensity,
i.e. lighter or darker. For explanation purposes, to represent an
increased intensity offset, i.e. bolder/darker than intended, the
actual intensity is shown by thicker dashed lines of markers 13a
and 13b. Similarly, the feature 14 is shown having thicker lines.
It should be understood that a faded or lighter feature 14 can also
appear on the substrate 10 to be overprinted. Such offsets can
occur, for example, due to printing errors, printing equipment
issues (nozzle blockage, spurting, etc), due to exposure to
environmental factors such as light and/or dirt, and for other
reasons.
[0072] The intensity information is conveyed to the controller 24
by the imager 20, which in turn actuates and controls the
overprinting mechanism 22 to compensate for the intensity offset,
so that a proper overprinting over or in relation to feature 14 is
achieved.
[0073] Alternatively, the compensation process may be done by the
processor using image processing, namely, by manipulating the
overprinting file according to the intensity offset. Then, printing
the manipulated file over or in relation to feature 14. Thus a
suitable overprinting can be performed.
[0074] FIG. 3F shows a still further example of a possible offset,
which will be termed a color offset. Here, the color(s) of the
feature 14, or portions thereof, may be different than the intended
color(s), e.g. a different color or shade. Such offsets can occur,
for example, due to printing errors, printing equipment issues
(blockage of nozzles or portions of nozzles relating to certain
color or colors), fading, cover-up or distortion as a result of
exposure to environmental factors such as light and/or dirt, and
for other reasons.
[0075] Sometimes the overprinting is the application of a symbol
(or text, etc) adjacent the feature 14, and a matching of color
with the feature, or a portion of it, is desired. Such an
overprinting is also considered within the scope of this
example.
[0076] The color(s) can be determined, for example, by the emitted
wavelength of the registration markers 12a and 12b and/or
feature(s) 14 previously printed on the substrate 10.
[0077] For explanation purposes, to represent an offset wherein the
color is different than intended, the actual color 13a and 13b is
shown as having curved dashed lines (and slightly larger and
shifted to the right so those lines can be seen more easily). To
represent an analogous relationship, the feature 14 is shown having
lines made up of a sequence of curved segments.
[0078] The imager 20 conveys the color information to the
controller 24 which in turn actuates and controls the overprinting
mechanism 22 to compensate for the difference in color--so that a
proper overprinting ink (varnish, colors, security inks, conductive
inks, etc) color is used.
[0079] Alternatively, the compensation process may be done by the
processor using image processing, namely, by manipulating the
overprinting file according to the color offset. Then, printing the
manipulated file over or in relation to feature 14. Thus a suitable
overprinting can be performed.
[0080] If the offset is global, the registration markers 12a and
12b and the feature 14 will be affected in an analogous manner.
Alternatively, the offset may be local. In other words, only some
features 14, or portions thereof, may be affected (have an offset).
Either way, the imager 20 can determine and quantify such offsets
and correct for them. The correction can be in the form of adding
or reducing the intensity (amount of ink, varnish, etc., and/or
perhaps its color) overprinted on the feature 14, or portion
thereof; or even blocking out unintended stray or miss-placed
lines/marks.
[0081] FIGS. 3G and 3H illustrate examples of local offsets, by way
of the feature 14 which is exemplified by a simply drawn house. In
FIG. 3G, the house feature 14 is missing the top of its roof. This
can be added during the overprinting. In addition to determining
and compensating for all of the aforementioned type offsets and
others not exemplified, if any, the processor 25 compares the
components of the feature 14 with a digitized image of the master
substrate (not shown) whose data has been digitized and stored. As
a result, the processor 25 determines that the roof top is missing
and actuates the overprinting mechanism 22 to add it, in addition
to any other overprinting applications.
[0082] Alternatively, the process may be done using image
processing.
[0083] In case that feature 14 is both missing a part and has one
or more offsets (such as in FIGS. 3A-3F), compensation process by
the processor using image processing may be done by manipulating
the digitized image of the master substrate according to the
specific offset(s) in order to print the missing part(s) in the
right position. Then, the overprinting file is manipulated
according to the same offset(s) in order to overprint over feature
14. Thus a suitable overprinting can be performed.
[0084] An application of the aforementioned example is one wherein
the overprinting completes or provides a portion of an electronic
circuit, for example by printing an electronic ink to connect the
ends of two portions of the electronic circuit.
[0085] FIG. 3H illustrates a slightly different issue. Here the
rooftop of the feature 14 is in an incorrect position. The
overprinting system performs a similar determination as just
described, however, when overprinting, it must first delete the
miss-positioned rooftop. This can be accomplished by determining
the background color and overprinting that color on the
miss-positioned rooftop in order to delete it, as well as
overprinting the roof top as it should be.
[0086] FIG. 4 is a flowchart illustrating an embodiment of a method
for overprinting wherein offset issues are taken into account. In a
first step 102, the substrate is fed or otherwise positioned on the
platform 18 of the overprinting system. Then, in a subsequent step
104, the substrate 10 is imaged, including imaging the registration
markers 12a and 12b and all features 14 on the substrate. In a next
step 106, the imager 20 provides a digitized image (image data) of
the substrate 10 to the processor 25 which receives and analyzes
the data and determines what compensation is required, if any, to
compensate for the offsets that may be present, in a step 108. The
controller 24 then, in a step 110, actuates the overprinting
mechanism 22 in a suitable manner, by way of signals for the
overprinting mechanism 22 to apply ink (varnish, colors, security
inks, conductive inks etc.) shifted linearly (x-y direction),
angularly, to compensate for intensity issues, color issues, local
anomalies, and the like. In a final step 112, the overprinting
mechanism 22 applies ink (varnish, colors, security inks,
conductive inks etc.) in accordance with the signals provided to it
by the controller 20.
[0087] In accordance with particular embodiments, the method
further comprises inputting data relating to the features 14 of the
substrate 10 as they are intended to be. In the case where local
anomalies are to be corrected, such inputting of data would be
required.
[0088] FIG. 5 is a flowchart illustrating another embodiment of a
method for overprinting wherein offset issues are taken into
account. In a first step 502, the substrate is fed or otherwise
positioned on the platform 18 of the overprinting system. Then, in
a subsequent step 504, the substrate 10 is imaged, including
imaging the registration markers 12a and 12b and all features 14 on
the substrate. In a next step 506, the imager 20 provides a
digitized image (image data) of the substrate 10 to the processor
25 which receives, analyzes the data, determines what compensation
is required, if any, to compensate for the offsets that may be
present and creates a corrected digital image. In a step 508 the
controller 24 transmits the printing data of the corrected digital
image to the printer in order to print the corrected image over or
in relation to feature 14.
[0089] In accordance with particular embodiments, the method
further comprises inputting data relating to the features 14 of the
substrate 10 as they are intended to be. In the case where local
anomalies are to be corrected, such inputting of data would be
required.
[0090] It should be understood that the above description is merely
exemplary and that there are various embodiments of the present
invention that may be devised, mutatis mutandis.
* * * * *