As part of container manufacturing, or in some cases during filling or sealing operations of containers, markings may be placed on a number of container locations including the end closure. The markings may serve a variety of purposes, including decorating the container, identifying contents, identifying the location or date of manufacture or use, identifying the maker of the container or container component, the style or materials for the container, providing trade names, advertising, promotion, or the like. In some situations, promotional information such as sweepstakes, contests, or some other indicia are placed or marked on containers or container components.
A variety of devices and procedures have been used for marking containers and container components, such as pull tabs. Currently the container body is the primary surface of a container that is marked. However, container bodies and the markings thereon are frequently obstructed during use of the container, such as by the consumer's hand during consumption of a beverage from a beverage container. Metal tabs used to open containers provide a unique and effective surface for marking with advertising and other indicia in new and creative ways. Unlike the container body, consumers naturally look at the tab to open the container. Further, the tab is typically not obstructed or blocked during consumption of a beverage from a beverage container.
Pull tabs, or “tabs” as discussed herein, are formed separately from the container body during an end closure manufacturing process. The manufacture of container end closures requires a number of processing steps collectively referred to as a conversion process. A typical conversion process is generally illustrated and described in “How Ball Makes Beverage Ends,” available at http://www.ball.com/images/ball_com/product_options_files/How_Ball_Makes_Beverage_Ends.pdf (last visited Mar. 16, 2015) and U.S. Pat. No. 6,533,518, which are incorporated herein by reference in their entirety. During the conversion process, an uncoiler feeds a continuous sheet of metal tab stock into a conversion press. The conversion press forms the sheet of metal into tabs and interconnects the tabs to the end closure with a rivet. Various methods of marking container tabs and other components of beverage containers are described in U.S. Pat. No. 6,105,806, U.S. Pat. No. 7,972,426, U.S. Pat. No. 7,638,252, U.S. Pat. No. 8,146,768, U.S. Patent Application No. 2005/0045637, U.S. Patent Application No. 2013/0075401, U.S. Patent Application No. 2013/0270269, and PCT International Publication No. WO 2013/049320 which are incorporated herein by reference in their entirety.
In some cases, embossing or incising processes have been used to mark containers and tabs. Embossing or incising, via stamping, can require an undesirably large inventory of tools for different kinds of lettering or symbols forming the marks. Further, embossing or incising processes typically require the need to shut down an assembly line or conversion press to disassemble the conversion press whenever it is necessary to replace tools for maintenance or repairs or to change the mark being incised or embossed. Such shutdowns are particularly troublesome when it is desirable to change the marks with relatively high frequency, such as when markings on containers or tabs are intended to be used as part of a contest or sweepstakes in which there are preferably a relatively large number of different possible markings or indicia. Furthermore, it is difficult to accurately control the depth of embossing or incising and, in some cases, embossing or incising that is too deep may lead to leakage or container/end closure failure.
Another process which has been used for placing markings on containers and tabs has been one or more printing processes. Contact or press printing is sometimes useful for decorating or placing markings on containers where it is desired to place a relatively large number of identical markings on containers. However, contact printing is believed impractical for many components, such as tabs, because of the shape or position of the tab. Contact printing is also inefficient when it is desired to change the marks with relatively high frequency because of the need to stop a production line and at least partially disassemble the contact print device in order to change the configuration of the markings being printed on the tabs.
In some situations, components of containers, including tabs, may be marked using a non-contact printing process such as an inkjet process. Although inkjet equipment can be controlled to provide changes in markings, inkjet processes and equipment have been found to be relatively unreliable and to require frequent maintenance and repair. Inkjet processes have also been found to be subject to unwanted placement or positioning of ink. For example, inkjet printing can result in a mist of ink which can interfere with the printing process, cause undesired markings on containers, or cause equipment malfunction. In some cases, the use of an inkjet process can result in the loss of up to 20% or more of potential production time due to the need for clean up, maintenance, and/or repair. It has also been found difficult to achieve reliable adhesion of the ink to containers or container components. Additionally, inkjet processes have been difficult to provide at high speed without slowing the conversion press and while maintaining print quality to mark letters or other indicia without distortion. Finally, inkjet printing and direct contact printing processes provide only surface markings without forming indentations or otherwise altering the containers or container components. Accordingly, inkjet and other printing processes are generally inappropriate for use in connection with contest sweepstakes or to provide other valuable tokens or indicia as there is an undesirably large potential for counterfeiting or altering of the markings in an attempt to claim a contest or sweepstakes prize.
Some or all of the above difficulties in previous container marking systems and methods are particularly troublesome for metallic containers or container components such as typical aluminum alloy beverage containers and tabs. As compared with plastic or other container materials, metallic containers can be relatively difficult to mark, at least because it can be difficult to adhere ink to metal surfaces, because of the harder surfaces of metallic containers, and because of the higher melting or softening point of the metal material of the metallic containers. Further, marking systems must be capable of operating quickly to ensure downstream production equipment, such as the conversion press, can operate at a rated speed of approximately 750 cycles (or strokes) per minute. Accordingly, devices and processes used in connection with some container materials are not necessarily applicable to others. Further, in most situations, the functions or purposes of markings placed on metallic containers will rarely justify use of different methods and apparatus which would involve expenses that are substantially in excess of those involved with current methods and apparatus or that require operating the production line at a slower speed.
One known system of decorating tabs is described in U.S. Pat. No. 6,498,318 which is incorporated herein by reference in its entirety. The system described in U.S. Pat. No. 6,498,318 solves the problems described above by using laser light to mark the sheet of metal tab stock used to form a tab. The system marks the tab stock before the conversion press forms the tab stock into tabs and interconnects the tabs to the end closures. However, the system is directly integrated to the conversion press and cannot operate out of phase with the conversion press. Because the system cannot run independently of the feed rate of the conversion press, the available laser print times are limited and cannot be increased without reducing the speed of the conversion press.
Another method of decorating tabs involves coating the tabs or tab stock with a lacquer including a color agent or a lacquer having photonically active material. A laser then removes predetermined portions of the lacquers (or alters the appearance of the lacquers) to form an image. These methods of marking tabs are generally considered to be unsuitable as the lacquers added to the tab unacceptably increase the productions costs of tabs substantially in excess of those involved with current processes.
Some other methods describe the use of more powerful lasers to form a desired mark on the tab. For example, one method describes the use of a 200 Watt or a 600 Watt laser. However, the energy required to power lasers of these strengths makes their use uneconomical in an end closure manufacturing process where several hundred thousand or millions of tabs are manufactured daily. For example, in one known end closure manufacturing facility up to 5 million tabs are manufactured daily.
Accordingly, there is an unmet need for systems and methods of marking containers and tabs that can be removably integrated with a container end closure production line and that can operate out of phase with the container end closure production line without decreasing the efficiency, or increasing the costs, of current container end closure manufacturing processes.