Apparatus for forming high definition lithographic images on containers
09962924 ยท 2018-05-08
Assignee
Inventors
Cpc classification
B41F17/08
PERFORMING OPERATIONS; TRANSPORTING
B41M1/40
PERFORMING OPERATIONS; TRANSPORTING
B41M1/20
PERFORMING OPERATIONS; TRANSPORTING
B41N1/006
PERFORMING OPERATIONS; TRANSPORTING
B41M1/22
PERFORMING OPERATIONS; TRANSPORTING
International classification
B41N1/00
PERFORMING OPERATIONS; TRANSPORTING
B41M1/40
PERFORMING OPERATIONS; TRANSPORTING
B41F17/08
PERFORMING OPERATIONS; TRANSPORTING
B41F7/16
PERFORMING OPERATIONS; TRANSPORTING
B41M1/22
PERFORMING OPERATIONS; TRANSPORTING
Abstract
The present invention relates to using soft photopolymer plates in a printing process, and more specifically, to an apparatus and methods of using soft photopolymer materials to decorate an exterior surface of cylindrical metallic containers with high definition graphics and other indicia.
Claims
1. An apparatus for forming a high-definition lithographic image on an exterior surface of a metallic container, comprising: a first inker operable to transfer a first ink to a first printing plate attached to a circumference of a first plate cylinder; a second inker operable to transfer a second ink to a second printing plate attached to a circumference of a second plate cylinder, wherein the second printing plate includes a relief area that will not receive the second ink; a blanket cylinder having one or more printing blankets affixed to a circumference of the blanket cylinder, each of the printing blankets having an image with a depth extending below a plane defined by a face portion of a printing blanket, the blanket cylinder operable to move the printing blankets into rotational contact with the first and second printing plates attached to the first and second plate cylinders, wherein the first ink is transferred from the first printing plate to the image on each of the printing blankets, and wherein the second ink is transferred from the second printing plate to a portion of each of the printing blankets, and wherein the relief area will not transfer the second ink to the image on each of the printing blankets; and a support cylinder operable to move the metallic container into contact with a printing blanket affixed to the blanket cylinder, wherein the first and second inks are transferred from the printing blanket to the exterior surface of the metallic container to form the high-definition lithographic image.
2. The apparatus of claim 1, wherein at least one of the printing blankets includes a relief area positioned around an image formed on the printing blanket.
3. The apparatus of claim 2, wherein the relief area does not accept ink from the printing plates such that an uninked area is formed on the metallic container.
4. The apparatus of claim 1, wherein each of the printing blankets comprises a photopolymer material with a different image formed thereon, and wherein each of the different images are formed by creating a film negative of each different image, placing the film negatives on predetermined portions of the printing blankets, exposing the printing blankets and the film negatives to light, removing the film negatives from the printing blankets, and cleaning the photopolymer material to remove unexposed material.
5. The apparatus of claim 1, wherein each of the images are formed in a same location on each of the printing blankets and the images align with the relief area of the second printing plate.
6. The apparatus of claim 1, wherein the depth is from about 0.0009 inch to about 0.089 inch.
7. The apparatus of claim 1, wherein the images are formed by removing material from the face portions of the printing blankets.
8. A decorator to decorate exterior surfaces of a plurality of metallic containers with different images, comprising: a first plate cylinder with a first printing plate which includes a first ink receiving region and a relief area that will not receive ink; a first inker to transfer a first ink to the first ink receiving region; a second plate cylinder with a second printing plate which includes a second ink receiving region; a second inker to transfer a second ink to the second ink receiving region; and a blanket cylinder aligned with the first and second plate cylinders, the blanket cylinder including a first transfer plate and a second transfer plate, the first transfer plate including a first image and the second transfer plate including a second image, at least a portion of the first and second images having a depth that extends below a face portion of the respective first and second transfer plates, wherein the blanket cylinder is operable to rotate with respect to the first and second plate cylinders such that the first ink receiving region of the first printing plate transfers the first ink to a portion of each of the first and second transfer plates and the second ink receiving region of the second printing plate transfers the second ink to the first and second images, wherein the relief area of the first printing plate aligns with the first and second images, wherein the first transfer plate subsequently contacts an exterior surface of a first metallic container which is decorated with the first ink and with the first image, and wherein the second transfer plate subsequently contacts an exterior surface of a second metallic container which is decorated with the first ink and with the second image.
9. The decorator of claim 8, wherein the first transfer plate comprises a photopolymer material from which some of the photopolymer material has been removed from the face portion to reveal the first image.
10. The decorator of claim 9, wherein portions of the first image have different depths.
11. The decorator of claim 8, wherein the first image of the first transfer plate is surrounded by a relief area that will not receive ink from the first and second printing plates such that the first image formed on the first metallic container is surrounded by a non-inked area.
12. The decorator of claim 8, further comprising a support cylinder to move the first and second metallic containers into contact with the first and second transfer plates.
13. The decorator of claim 8, wherein at least one of the first and second transfer plates is comprised of at least one of an elastomer which is curable by a photopolymerization process, a chloroprene cross-linked with trimethylolpropane triacrylate, and a styrene-isoprene rubber with a polyacrylate.
14. The decorator of claim 8, wherein no portion of the first image projects above a first plane defined by the face portion of the first transfer plate.
15. The decorator of claim 8, wherein the depth of the first image on the first transfer plate is from about 0.0009 inch to about 0.089 inch.
16. A decorator with a photopolymer plate to decorate an exterior surface of a generally cylindrical container, comprising: a blanket cylinder; a first photopolymer plate affixed to the blanket cylinder, the first photopolymer plate including a first image formed thereon, wherein at least a portion of the first image has a depth that is lower than a first plane defined by a face portion of the first photopolymer plate and no portion of the first image projects above the first plane; a first plate cylinder; a first printing plate interconnected to the first plate cylinder, wherein the first printing plate is operable to transfer a first ink to at least a portion of the first photopolymer plate; a second plate cylinder; a second printing plate interconnected to the second plate cylinder, the second printing plate including a second image, wherein the second printing plate is operable to transfer a second ink from the second image to the first photopolymer plate, and wherein the second printing plate does not transfer the second ink to the first image; and a support element to move the generally cylindrical container into contact with the first photopolymer plate, wherein the first and second inks are transferred from the first photopolymer plate to the exterior surface of the generally cylindrical container to form the first and second images on the generally cylindrical container.
17. The decorator of claim 16, wherein the first photopolymer plate is comprised of a photo-curable material that has been cured by light to form the first image.
18. The decorator of claim 16, wherein the first image on the first photopolymer plate is a negative comprising relief areas that will not receive ink from the first printing plate.
19. The decorator of claim 16, further comprising a second photopolymer plate affixed to the blanket cylinder, the second photopolymer plate including a third image formed thereon, wherein the first printing plate is operable to transfer the first ink to at least a portion of the second photopolymer plate and the second printing plate is operable to transfer the second ink from the second image to the second photopolymer plate, wherein the second printing plate does not transfer the second ink to the third image, and wherein the first and second inks are subsequently transferred from the second photopolymer plate to an exterior surface of a second generally cylindrical container to form the second and third images on the second generally cylindrical container.
20. The decorator of claim 16, wherein the first image on the exterior surface of the generally cylindrical container is formed of the first ink and the second image is formed of the second ink.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and together with the Summary of the Invention given above and the Detailed Description of the drawings given below, serve to explain the principles of these embodiments. In certain instances, details that are not necessary for an understanding of the disclosure or that render other details difficult to perceive may have been omitted. It should be understood, of course, that the invention is not necessarily limited to the particular embodiments illustrated herein. Additionally, it should be understood that the drawings are not necessarily to scale.
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(20) To assist in the understanding of one embodiment of the present invention the following list of components and associated numbering found in the drawings is provided herein:
(21) TABLE-US-00001 Number Component 2 Printing plate 4 Face portion 6 Back portion 8 Ink receiving region 10 Non-ink region 12 Relief area 14 Soft photopolymer plate 16 Ink receiving region 18 Image 20 Relief area 22 Screened area 24 Decorator 26 Plate cylinder 28 Inker 30 Rollers 32 Blanket cylinder 34 Metallic container 36 Conveyor 38 Support cylinder 40 Station for metallic container 42 Storage facility 44 Container surface 46 Non-inked portion
DETAILED DESCRIPTION
(22) The present invention has significant benefits across a broad spectrum of endeavors. It is the Applicant's intent that this specification and the claims appended hereto be accorded a breadth in keeping with the scope and spirit of the invention being disclosed despite what might appear to be limiting language imposed by the requirements of referring to the specific examples disclosed. To acquaint persons skilled in the pertinent arts most closely related to the present invention, a preferred embodiment that illustrates the best mode now contemplated for putting the invention into practice is described herein by, and with reference to, the annexed drawings that form a part of the specification. The exemplary embodiment is described in detail without attempting to describe all of the various forms and modifications in which the invention might be embodied. As such, the embodiments described herein are illustrative, and as will become apparent to those skilled in the arts, may be modified in numerous ways within the scope and spirit of the invention.
(23) Although the following text sets forth a detailed description of numerous different embodiments, it should be understood that the detailed description is to be construed as exemplary only and does not describe every possible embodiment since describing every possible embodiment would be impractical, if not impossible. Numerous alternative embodiments could be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims. To the extent that any term recited in the claims at the end of this patent is referred to in this patent in a manner consistent with a single meaning, that is done for sake of clarity only so as to not confuse the reader, and it is not intended that such claim term by limited, by implication or otherwise, to that single meaning.
(24) Referring now to
(25) Printing plates 2B may also be formed with a relief area 12, as illustrated in
(26) After one or more of the ink receiving regions 8, non-ink regions 10, and/or relief areas 12 are formed on a printing plate 2, the plate 2 is attached to a plate cylinder of a decorator, discussed below in conjunction with
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(28) In one embodiment the soft photopolymer plates have a thickness of about 0.04 inch to about 0.1 inch. In one preferred embodiment, the thickness of the soft photopolymer plates is from about 0.060 inch to about 0.090 inch. In another preferred embodiment, the soft photopolymer plates are about 0.05 inch thick. In still another preferred embodiment, the soft photopolymer plates are about 0.0725 inch thick. Soft photopolymer plates of other suitable thicknesses may also be used with the present invention. In one embodiment, the soft photopolymer plates have a hardness of from about 40 durometers to about 110 durometers. In a preferred embodiment, the hardness of the soft photopolymer plates is from about 60 durometers to about 100 durometers. In another preferred embodiment, the hardness of the soft photopolymer plates is from about 50 durometers to about 90 durometers. However, soft photopolymer plates that are harder or softer may be used with the method of the present invention. In one embodiment, the hardness of the soft photopolymer plates is measured after the plates have been cured and an image formed thereon as described below. The soft photopolymer plate may be made of any photo-curable material, whether made of a polymer or not. One example is a UV-curable material. Another example is made of a material cured by light of a different wavelength, not necessarily UV light. Although many such plates are made of polymer compositions today, the current invention is applicable to plates made of any material and composition that are curable by light of a desired wavelength. In one embodiment, the photopolymer plate is comprised of elastomers which are cured using a light-catalyzed photopolymerization process. In another embodiment, the photopolymer plate is comprised of chloroprene cross-linked with trimethylolpropane triacrylate. In still another embodiment, the photopolymer plate is comprised of styrene-isoprene rubber with a polyacrylate. Still other embodiments may use soft photopolymer plates comprised of other suitable light-curable materials known to those skilled in the art or developed in the future.
(29) Soft photopolymer plates have primarily been used for creating high resolution graphics on flexible plastic packaging (such as soft plastic vegetable and produce bags), tags, labels, folding cartons, and tissue wrappers. Soft photopolymer plates are not known to have been used in the metallic container industry due to the significant challenges of high speed printing on an exterior surface of a metallic substrate.
(30) Referring now to
(31) Images are formed on the soft photopolymer plates 14 with a computer to plate (CTP) process, a conventional plate exposure process, or any other suitable method. A piece of soft photopolymer plate 14 with a Mylar backing is generally used as a backing, although other materials commonly known by one skilled in the art may also be employed as a backing. An image 18 to be printed onto an exterior surface of the metallic container is formed.
(32) In the conventional plate exposure process, a film negative of the image 18 is created. The film negative is placed on a predetermined portion of the face portion 4 of the soft photopolymer plate 14. The soft photopolymer plate 14 with the film negative is then placed into an exposure device that exposes the soft photopolymer plate and the film negative to a light source. The film negative acts as a negative mask that blocks and prevents some of the light from reaching the face portion 4 of the soft photopolymer plate 14. The light shines through the clear sections of the film negative and hardens the material of the soft photopolymer plate 14. Exposure time to an ultraviolet light source may range from approximately 0.01 minute to approximately 10 minutes.
(33) The material on the face portion 4 of the soft photopolymer plate 14 hardens where light passes through the film negative and strikes the face portion 4. Portions of the soft photopolymer plate 14 that are not covered by the film negative are also exposed to the light and harden. The material on the face portion of the soft photopolymer plate 14 under the areas of the film negative that block the light, or some of the light, remain unexposed and soft.
(34) Using the CTP process, the image 18 is transferred directed to the plate in a digital imager apparatus. The digital imager apparatus ablates, or otherwise removes, portions of an opaque mask coating on the face portion 4 of the soft photopolymer plate 14 to form a negative of the image 18. The soft photopolymer plate 14 is then placed into an exposure device that exposes the soft photopolymer plate to a light source. The exposure device may be the same as, or similar to, the exposure device used in the conventional plate exposure process described above. Portions of the mask coating that were not ablated block light and prevent the light from reaching the face portion 4 of the soft photopolymer plate 14. The polymer material of the soft photopolymer plate 14 under remaining portions of the mask coating remains unexposed and soft. Light from the exposure device contacts the polymer material of the soft photopolymer plate in the image areas where the mask coating has been removed and hardens the material of the soft photopolymer plate 14. Exposure time to an ultraviolet light source may range from approximately 0.01 minute to approximately 10 minutes. An example of the CTP process is described in Advancing Flexography, The Technical Path Forward by Ray Bodwell and Jan Scharfenberg, available at http://www2.dupont.com/Packaging_Graphics/en_US/assets/downloads/pdf/AdvFlexo_Brochure.pdf, which is herein incorporated by reference in its entirety. Examples of suitable digital imager apparatus are described in Cyrel? Digital flex plate Imagers (CDI), available at http://www2.dupont.com/Packaging_Graphics/en_GB/assets/downloads/pdf/CDI_family_English.pdf, which is herein incorporated by reference in its entirety.
(35) Once the image is transferred to the soft photopolymer plate 14 using either the CTP process or the conventional plate exposure process, the soft, unexposed polymer material on the face portion 4 of the exposed soft photopolymer plate 14 is removed. In one embodiment, the exposed soft photopolymer plate 14 is placed in a washing station. The unexposed, soft polymer material on unexposed areas of the face portion 4 of the soft photopolymer plate 14 is removed by washing and scrubbing the face portion 4. The washing station may include either water or a solvent, such as Cyrel Nutre-Clean. As will be appreciated, other solutions and solvents may be used in the washing station. In another embodiment, the unexposed polymer material is removed from the face portion by a post processing apparatus that does not use solvents and/or other liquids. The post processing apparatus may use thermal energy and a developer roll to remove the unexposed polymer material. After the soft, unexposed polymer material is removed, the soft photopolymer plate 14 may be exposed to light a second time to complete polymerization and ensure all areas of the plate have been hardened and to attain maximum durability.
(36) When the unexposed soft material on areas of the face portion 4 of the soft photopolymer plate 14 have been removed, the face portion 4 will have relief areas 20 that will not receive ink and hardened areas forming images 18 that can receive ink. The image 18 formed on the soft photopolymer plate can be three dimensional and have different depths in the face portion 4 depending on the amount of light that passed through the film negative or the masking coating. The image 18, or portions of the image, have a depth of about 0.0009 inch to about 0.089 inch. In a more preferred embodiment, the depth of the image 18, or within portions of an image 18, is from approximately 0.001 inch to approximately 0.084 inch deep. In some embodiments, the soft photopolymer plates 14 may also be etched or engraved on the face portion 4 before, during, or after the curing process to form one or more additional recessed portions. The etched or engraved areas may be formed using a laser or any other means known by those of skill in the art.
(37) The images 18 have a maximum thickness equal to the original thickness of the photopolymer plate 14. The images 18A, 18B can be surrounded by relief areas 20A, 20B that were not exposed and therefore remained soft. The unexposed, soft material of the soft photopolymer plates was subsequently removed to form the relief areas 20A, 20B. The size, location, and shape of the relief area formed in the soft photopolymer plates may align with the size, location, and shape of the non-ink region 10 illustrated in
(38) After the image 18 has been formed on the face portion 4 of the soft photopolymer plate 14, an adhesive transfer tape or adhesive stickyback may be added to the Mylar portion or other backing on the back portion 6 of the soft photopolymer plate 14. Suitable adhesive stickyback is available from a variety of commercial suppliers. In one embodiment, the adhesive stickyback is about 2.0 mil (or about 0.002 inch) thick. In another embodiment, the adhesive stickyback is about 15 mil (or about 0.015 inch) thick. The soft photopolymer plate 14 with the stickyback on the back portion 6 is then attached to the blanket cylinder of the decorator.
(39) Although not illustrated in
(40) Referring now to
(41) In the example illustrated in
(42) The decorator 24 also includes a blanket cylinder 32 to which one or more soft photopolymer plates 14 are attached. Additionally, or alternatively, the one or more soft photopolymer plates 14 can be a sleeve or cylinder of a soft photopolymer material that wraps around the circumference of the blanket cylinder 32. The blanket cylinder 32 rotates in a second direction opposite to the first direction of the plate cylinder 26. Each soft photopolymer plate 14 may have a different image 18 formed thereon. For example, the soft photopolymer plates 14 illustrated in
(43) The plate cylinders 26 rotate in the first direction and the blanket cylinder 32 rotates in the second opposite direction in unison to bring the printing plates 2 into contact with the soft photopolymer plates 14. Ink is transferred to the ink receiving regions 16 and images 18 of the soft photopolymer plates 14 that contact the inked ink receiving regions 8 of the printing plates 2. The main image exposure occurs on the inked printing plates 2 and a secondary image is produced by the soft photopolymer plates 14. The soft photopolymer plates 14 may have ink receiving regions 16 that are common for all of the soft photopolymer plates 14. The areas where images 18 are formed on the soft photopolymer plates, such as the images 18A, 18B illustrated in
(44) In operation, a metallic container 34 is fed to a support cylinder 38 by a conveyor 36 or other means from a storage location or facility 42. The support cylinder 38 has a plurality of stations 40 adapted to receive and hold a metallic container 34 in a predetermined position aligned with the soft photopolymer plates 14. The stations 40 can hold the metallic containers 34 in a stationary position and can also rotate the metallic containers 34 about each container's longitudinal axis. As the blanket cylinder 32 rotates in the second direction, the support cylinder 38 rotates in unison in the first direction to bring an exterior surface 44 of the metallic container 34 into rotational contact with an inked soft photopolymer plate 14 attached to the blanket cylinder 32. The ink is then transferred from the soft photopolymer plate 14 to the exterior surface 42 of the metallic container 34. Although a support cylinder 38 is illustrated in
(45) Two decorated metallic containers 34A, 34B are also illustrated in
(46) Decorators 24 used in the commercial metallic container industry may have blanket cylinders 32 with from 8 to 12 individual soft photopolymer plates 14 attached. When each of the 8 to 12 individual soft photopolymer plates 14 has a unique image 18 formed thereon, the decorator 24 can produce from 8 to 12 different lithographic images without changing the printing plates 2. The present invention will work with a blanket cylinder 32 with any number of soft photopolymer plates 14 attached to its circumference. In addition, although the soft photopolymer plates 14 are illustrated in
(47) Referring now to
(48) Referring now to
(49) Referring now to
(50) The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limiting of the invention to the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments described and shown in the figures were chosen and described in order to best explain the principles of the invention, the practical application, and to enable those of ordinary skill in the art to understand the invention.
(51) While various embodiments of the present invention have been described in detail, it is apparent that modifications and alterations of those embodiments will occur to those skilled in the art. However, it is to be expressly understood that such modifications and alterations are within the scope and spirit of the present invention, as set forth in the following claims. Further, the invention(s) described herein is capable of other embodiments and of being practiced or of being carried out in various ways. In addition, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of including, comprising, or having and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.