The present invention relates to plastic containers having digital images printed thereon, particularly curved plastic containers.
Conventional techniques for printing onto curved plastic containers are subject to significant drawbacks. For example, it is difficult to obtain proper registration between colors, and changing images, designs or wording is expensive and time consuming.
Inkjet printing with multiple nozzles is useful for flat surfaces. However, it is difficult to satisfactorily use multiple nozzles on curved surfaces.
It would be highly desirable to print a digitally generated image directly onto a plastic container, particularly a curved plastic container, wherein the printing can be done at a reasonable speed and at a reasonable cost.
The present invention provides for printing digital images or indicia directly onto a plastic container, particularly a curved, plastic container, and accomplishing this in a continuous operation at a reasonable speed and at a reasonable cost. Full color digital graphic images or indicia may be directly printed onto containers at multiple areas thereon.
In accordance with the present invention a series of plastic containers are firmly held and moved to and from a first digital printing location and a first digital image is printed thereon at the first printing location on a first printing area on the containers, with the containers held at the top thereof and at a second position spaced from the top thereof, preferably at the base. Desirably, the containers are moved from the first digital printing location to a second digital printing location and a second digital image printed thereon on a second printing area on the containers spaced from the first printing area, with the containers held at the top thereof and at a second area spaced from the top, preferably at the base. The containers are preferably maintained under internal pressure while the digital image or images are printed thereon.
The steps of digitally printing the digital image directly onto the plastic container prints the digital images directly onto a preformed container, for example onto an injection molded or blow molded container, such as polyethylene terephthalate (PET) or high density polyethylene (HDPE). The digital printing operation may print the digital image directly onto the plastic container as by jetting ink through an inkjet print head and onto the container surface. The ink may be a UV-reactive ink, in which case after printing the ink may be cured by exposure to UV light. One may also, for example, treat the container surface to be printed prior to the printing operation, as by flame treatment, corona treatment or plasma jet treatment.
Further features of the present invention will be discussed hereinbelow.
The present invention will be more readily understandable from a consideration of the following illustrative drawings, wherein:
As can be seen from
As can be seen, particularly in
Upon clamping container 11 at the container entry 16 internal pressure is applied to the inside of the container via air pressure means 32 and pressure line 34 (
As the containers enter the track curved portion or radius 28 they first pass through a first pre-treatment location A-1, see
The containers will then pass the first printing site 30, area B-1 in
The printed containers will then pass through a first curing station C-1, which will cure the ink or inks applied at the first printing site 30. This may be an ultra violet light source or other radiant curing method.
The containers 11 then enter a straight section 42 of container track 26 where they are rotated, as for example, 180°, to expose second surface 44 of the containers to the second printing site 46, as by the clamp assembly 18 or other rotating means. The second container surface 44 is spaced from the first container surface 38, desirably an area opposed to the first container surface, as 180° therefrom.
After rotation the containers 11 with container first surface 38 having printing thereon are moved through a second pre-treatment area A-2 where the surface energy of the container on the container second surface 44 is raised as at the first pre-treatment area A-1. The containers will then pass the second printing site 46, area B2, wherein the second printing will be performed on the second surface 44 of the containers.
Similar to first printing site 30, printing at the second printing site may be a direct drop on demand inkjet head as shown in
The printed containers will then pass through a second curing station C-2 which will cure the ink or inks applied at the second printing site. Here again, this may be an ultra violet light source other radiant curing method.
The container clamp assembly 18 will then release the containers, printed on two sides or two locations and pass them on to an out-feed conveyer or storage and return to repeat the cycle.
In the printing procedure it is desirable to maintain a plurality of print heads at a constant distance and perpendicularity from the non-planar container surface during the printing process. A plurality of print heads may be desirably articulated during the printing process to maintain a constant distance and perpendicularity from the non-planar container surface. A plurality of sensors may be used to measure the curvature of the non-planar surface and to control the articulation of the plurality of print heads to maintain the constant distance and perpendicularity from the non-planar surface. The print heads and/or container are desirably moved at a constant velocity relative to the non-planar surface during the printing process. Also real time control is preferably provided to the printing control system to determine the relative position of the non-planar surface to the printing process. The foregoing features provide improved digital printing on the curved container surface.
Thus, for example, as shown in
Thus, the present invention provides an improved procedure for printing digital images or indicia directly onto a curved plastic container. The procedure is continuous and efficient and enables two sides or two areas to be efficiently printed.
It is to be understood that the invention is not limited to the illustrations described and shown herein, which are deemed to be merely illustrative of the best modes of carrying out the invention, and which are susceptible of modification of form, size, arrangement of parts and details of operation. The invention rather is intended to encompass all such modifications which are within its spirit and scope as defined by the claims.
This application is a continuation of application Ser. No. 11/446,792, filed Jun. 5, 2006, now pending, which is a division of application Ser. No. 11/219,411, filed Sep. 2, 2005, issued as U.S. Pat. No. 7,210,408 on May 1, 2007, which claims priority from Provisional Application No. 60/640,605, filed Dec. 30, 2004.
Number | Date | Country | |
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60640605 | Dec 2004 | US |
Number | Date | Country | |
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Parent | 11219411 | Sep 2005 | US |
Child | 11446792 | US |
Number | Date | Country | |
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Parent | 11446792 | Jun 2006 | US |
Child | 12768196 | US |