Reference is made to commonly-assigned co-pending U.S. patent application Ser. No. 11/615,025, filed Dec. 22, 2006, now U.S. Publication No. 2008/0153038, entitled HYBRID OPTICAL HEAD FOR DIRECT ENGRAVING OF FLEXOGRAPHIC PRINTING PLATES, by Siman-Tov et al.; and U.S. patent application Ser. No. 11/424,919, filed Jun. 19, 2006, now U.S. Publication No. 2008/0018943, entitled DIRECT ENGRAVING OF FLEXOGRAPHIC PRINTING PLATES, by Eyal et al.; the disclosures of which are incorporated herein.
The present invention relates to 3D imaging of a flexographic plate by using multiple emitters. The multiple emitters are configured to engrave on the same region of the flexographic plate during different time periods.
Prior to setting forth the background of the invention in detail, it may be helpful to set forth definitions of certain terms that will be used hereinafter. The term computer-to-plate (CTP) as used herein relates to an imaging technology used in modern printing processes. In this technology, an image created in a desktop publishing application is output directly to a printing plate. CTP as used hereinafter relates also to the imaging device carrying out the process of outputting the computer-stored image to printing plates.
There are different types of printing plates used by CTP imaging devices. Most plates require post processing steps to produce two or three-dimensional features. The present invention refers to the type of plate known as flexographic printing plates. More specifically it refers to a CTP imaging device that is used for direct engraving of a flexography plates utilizing a light source configured from multiple emitters.
Direct engraving of a flexography plates means three-dimensional (3D) carving on the plate material by applied light source energy such as a laser. The concept of direct engraving is remarkably different from two-dimensional imaging techniques which require post processing steps in order to produce three-dimensional features on a plate to be applicable for the flexography market.
Group 112 emits light 136 on plate surface 108 during first drum revolution 124, group 116 emits light 140 during the second drum revolution 128, and group 120 emits light 144 during the third drum revolution 132. Each of the three groups 112, 116, and 120 in the previous example emit light on the same region of plate surface 108, i.e. pixels p1, p2, and p3 of pixels array 160 are affected by the three groups.
Additionally, during the second drum revolution 128 the first group of emitters 112 emits light 148 on pixels p4-p6. During the third drum revolution 132 pixels p4-p6 are affected by the second group of emitters 116 emitting light 152, while the first group of emitters 112 emit light 156 on pixels p7-p9. The emitters described by the prior art are all imaged just on the surface plane of the flexographic printing plate.
The present invention propose new embodiments concepts for CTP machines, wherein a light source, configured from multiple emitters, is adjusted in a slant or stair configuration relative to the surface plane of the flexographic plate. The slant or stair configuration enables simultaneously imaging different emitters on both the surface plane and at various depths within the printing plate. The multiple emitters are then activated in a way that enhances the direct engraving and ablating effect.
Briefly, according to one aspect of the present invention an imaging head writes an image on a substrate. The head includes an array of emitters comprised of groups of emitters; imaging lens that focuses light from each group onto the substrate; and wherein light from each group is focused at a different depth relative to a surface of the substrate.
The invention and its objects and advantages will become more apparent in the detailed description of the preferred embodiment presented below.
The subject matter regarded as the invention will become more clearly understood in light of the ensuing description of embodiments herein, given by way of example and for purposes of illustrative discussion of the present invention only, with reference to the accompanying drawings wherein:
In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the disclosure. However, it will be understood by those skilled in the art that the teachings of the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, components and circuits have not been described in detail so as not to obscure the teachings of the present disclosure.
Multiple emitters array 104 is shown as part of an imaging head 404, which includes at least the array of multiple emitters 104 and an imaging lens 408 such as a telecentric lens. The array of emitters emits light, which is focused by the imaging lens 408 on pixels 160 of printing plate 416. The printing plate 416 is wrapped around, the imaging drum 412, and is imaged by imaging head 404 as the drum rotates.
The configuration in
In order to achieve more efficient engraving on plate surface 108, the focal plane of the emitted light applied on the same region should be substantially different for each subsequent drum revolution.
Similarly
An array 204, with multiple group of emitters offset to each other, is difficult to manufacture.
Similarly
While the invention has been described with respect to a limited number of embodiments, these should not be construed as limitations on the scope of the invention, but rather as exemplifications of some of the preferred embodiments. Other possible variations, modifications, and applications are also within the scope of the invention. For example, even though one imaging lens has been shown, multiple lenses may be used.
Number | Name | Date | Kind |
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4376282 | Kotani et al. | Mar 1983 | A |
6150629 | Sievers | Nov 2000 | A |
20020195012 | Juffinger et al. | Dec 2002 | A1 |
20080018943 | Eyal et al. | Jan 2008 | A1 |
20080153038 | Siman-Tov et al. | Jun 2008 | A1 |
20080225108 | Koizumi et al. | Sep 2008 | A1 |
Number | Date | Country |
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2 098 366 | Sep 2009 | EP |
WO 2007149208 | Dec 2007 | WO |
WO 2009029167 | Mar 2009 | WO |
Number | Date | Country | |
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20110058010 A1 | Mar 2011 | US |