The present invention relates to overprinting, and more particularly to adaptive corrected overprinting.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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 pre-printed 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.
It is an object of the present invention to disclose an adaptive overprint system for providing an overprint upon a substrate; the substrate comprising a plurality of registration markers at predetermined locations thereon and at least one pre-printed feature; the system comprising: an imager for capturing a digital image of said substrate with said registration markers and said feature; a printing platform upon which the substrate resides during overprinting; a printing mechanism for stamping said overprint upon said pre-printed feature; a controller operatively connected to said imager and said printing mechanism; and a handling device to move the substrate in and out of the printer; wherein said controller is adapted to identify and calculate the shift in said pre-printed feature based on said image of the substrate received from said imager, and to calculate a correlating compensation or correction shift to be electronically applied to the overprinted image.
It is within the scope of the above mentioned overprint system that the above mentioned shift is selected from a group consisting of: a global shift, a local shift, a linear shift, an angular shift, a size shift, an intensity shift, a color shift, or any combination thereof.
The overprint system as defined above additionally comprising a means for storing a log of the substrates identified as requiring shift adaptive overprint intervention.
It is within the scope of the above mentioned overprint system, additionally comprises a sorting means for stacking adaptively overprinted substrates separately from overprinted substrates that did not require shift adaptive intervention.
It is within the scope of the above mentioned overprint system, additionally comprises a means for marking substrates that have undergone shift adaptive overprinting.
It is within the scope of the above mentioned overprint system, additionally comprises a computerized means for selecting shifts that should be discarded, said shifts selected from a group consisting of: a global shift, a local shift, a linear shift, an angular shift, a size shift, an intensity shift, a color shift, or any combination thereof.
It is within the scope of the present invention that the above mentioned printing mechanism comprises an inkjet printing head.
It is within the scope of the present invention that the above mentioned overprint system is adapted to produce a UV spot coating.
It is yet another object of the present invention to disclose a method of adaptive overprinting on a substrate having a plurality of registration markers at predetermined locations thereon that has been pre-printed with at least one feature, said feature having being printed with a shift , the method comprising steps of: obtaining an adaptive overprint system for providing an overprint upon a substrate; the substrate comprising a plurality of registration markers at predetermined locations thereon and at least one pre-printed feature; the system comprising: an imager for capturing a digital image of said substrate with said registration markers and said feature; a printing platform upon which the substrate resides during overprinting; a printing mechanism for stamping said overprint upon said pre-printed feature; a controller operatively connected to said imager and said printing mechanism; and a handling device to move the substrate in and out of the printer; capturing a digital image of the substrate, comprising capturing said plurality of registration markers and said feature to be overprinted; producing image data related to the shift in said captured image; analyzing said image data to produce an appropriately shifted printing instructions; overprinting on the substrate in accordance with said shifted printing instruction, and thereby aligning said overprint with said pre-printed feature by shifting said overprint to match said original shift in said pre-printed feature.
It is within the scope of the present invention that the above mentioned shift is selected from a group consisting of: a global shit, a local shift, a linear shift, an angular shift, a size shift, an intensity shift, a color shift, or any combination thereof.
It is within the scope of the present invention that the above mentioned method of adaptive overprinting, additionally comprises a step of storing a log of the substrates requiring shift adaptive overprint intervention.
It is within the scope of the present invention that the above mentioned method of adaptive overprinting, additionally comprises a step of sorting said overprinted substrates and stacking adaptively overprinted substrates separately from overprinted substrates that did not undergo shift adaptive intervention.
It is within the scope of the present invention that the above mentioned method of adaptive overprinting, additionally comprises, additionally comprises a step of marking substrates that have undergone shift adaptive overprinting.
It is within the scope of the present invention that the above mentioned method of adaptive overprinting, additionally comprises a step of selecting shifts that should be discarded, said shifts selected from a group consisting of: a global shift, a local shift, a linear shift, an angular shift, a size shift, an intensity shift, a color shift, or any combination thereof; and consequently discarding substrates identified as having said selected shifts.
It is yet another object of the present invention to disclose a method of compensating or correcting for shift or printing anomaly on a pre-printed substrate, comprising the steps of obtaining an adaptive overprint system for providing an overprint upon a substrate; the substrate comprising a plurality of registration markers at predetermined locations thereon and at least one pre-printed feature; the system comprising: an imager for capturing a digital image of said substrate with said registration markers and said feature; a printing platform upon which the substrate resides during overprinting; a printing mechanism for stamping said overprint upon said pre-printed feature; a controller operatively connected to said imager and said printing mechanism; and a handling device to move the substrate in and out of the printer; positioning said substrate in an overprinting system; capturing an image of said substrate to produce image data; analyzing said image data to determine a suitable compensation for overprinting; and, actuating a printing mechanism to print on the substrate according to the determined compensation.
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:
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.
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.
The term ‘plurality’ refers hereinafter to any integer number equal or higher than one, e.g., 2, 3, 4, etc.
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.
The aforementioned meanings and explanations of the interchangeable terms misalignment, skew and shift should become clearer upon reading of the detailed description.
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.
The ‘pre-printed feature’ refers hereinafter to any image or markings that have stamped upon a substrate prior to being introduced to the overprint system.
Advantages of the overprinting system and method of the present invention include:
1. It does not require set up and does not require plates, screens or pre-press preparation.
2. It can be used for flood coating or spot coating, e.g. a UV spot coating.
3. It is conveniently used with most common paper sizes in the conventional and digital printing industry.
4. The coating is determined directly from a computer file.
The system also comprises a device (not seen) for moving the paper 10 from the platform 18 where printing 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.
In accordance with particular embodiments, the printing 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 printing 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).
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 is one or both of the x-direction and/or y-direction—or in combination with the printing mechanism 22.
Prior to applying the overprint, the imager 20 images the substrate 10 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 “d” units in the x-direction. This information is conveyed to the controller 24 which in turn actuates and controls the printing mechanism 22 to compensate for this offset. Thus an accurate overprinting can be performed.
In a similar manner as described with reference to
Again, prior to applying the overprint, the imager 20 images the substrate 10 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 printing mechanism 22 to compensate for this offset so that an accurate overprinting can be produced.
Once again, prior to applying the overprint, the imager 20 images the substrate 10 and thereby determines and quantifies the aforementioned enlargement, and there is a compensating effect applied by the overprinting system for this offset.
The intensity information is conveyed to the controller 24 by the imager 20, which in turn actuates and controls the printing mechanism 22 to compensate for the intensity offset, so that a proper overprinting is achieved.
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.
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.
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.
The imager 20 conveys the color information to the controller 24 which in turn actuates and controls the printing mechanism 22 to compensate for the difference in color—so that a proper overprinting ink (varnish, etc) color is used.
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.
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.
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.
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.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/IL08/01323 | 10/6/2008 | WO | 00 | 5/16/2011 |
Number | Date | Country | |
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60960637 | Oct 2007 | US |