Incremental printing of symbolic information – Light or beam marking apparatus or processes
Reexamination Certificate
1999-07-23
2002-08-06
Pham, Hai (Department: 2861)
Incremental printing of symbolic information
Light or beam marking apparatus or processes
C219S121600
Reexamination Certificate
active
06429889
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates in general to directly marking discrete consumable articles such as pills, capsules, tablets, and the like; and, in particular, to rapidly marking such discrete articles on the fly without the deposition of any ink or other external marking material to the articles, and without degrading the articles. With the use of ultraviolet laser energy such articles can be precisionly marked at rates of speed previously unobtainable, and while the articles remain in continuous motion. Uniquely, the marking can be accomplished even when the articles are fully encapsulated in a transparent package.
2. Description of the Prior Art
The pharmaceutical industry today produces billions upon billions of human consumable articles such as therapeutically effective pills, tablets, jell-caplets, and the like. These articles contain a wide variety of different prescription and non-prescription drugs, and due to the wide variety and large production quantity of these consumed articles numerous health problems and concerns have arisen. For example, there has become an increasing need to provide direct identification on each individual consumable article, particularly therapeutically effective articles, so their contents can be traced at a later date. This has been found to be very valuable for the elderly where over prescription problems can result, as described in Nellhaus U.S. Pat. No. 5,845,264. Nellhaus describes the application of bar codes directly to consumable drugs by utilizing conventional high resolution printing techniques. These techniques deposit selected amounts of a marking material directly on the surface of the drugs, such as non-toxic or inert ink. A common technique is to apply food grade ink approved by the Food and Drug Administration with an ink jet or rotary wheel printer.
Individually marking individual consumable article has many advantages. For one, the articles can always be identified and distinguished from other articles even when removed from their containers or packaging. In addition, they can always be distinguished from other non-pharmaceutical consumable articles such as candies, and the like. With the individual marking of each consumable article, serious life threatening mistakes can be avoided. Such individual marking is also advantageous as accidental overdose situations, and the like, can be more quickly diagnosed.
Ablative laser marking of tablets had been proposed previously. Gajdos U.S. Pat. No. 4,906,813 teaches treating tablets with a gas laser beam to induce marking by ablatively burning off layers of the tablets. Riddle U.S. Pat. No. 5,294,770 teaches drilling drug release ports in pharmaceutical tablets with a laser. Undesirably, in both of these teachings, the laser energy is provided at such a high concentration as to physically burn off material from the surface of the tablet, that is, ablatively remove a portion of the material from the tablet. The removal leaves voids that can readily be seen with a 5X or less powered microscope. This ablation can cause many problems. Clear, sharp marking is difficult to achieve depending on the amount of chipping that occurs due to the ablative activity. In addition, the burning caused by the laser may chemically alter the remaining material of the tablet near the mark, which is highly undesirable in pharmaceutical applications. Thus, in order to make it feasible to mark consumable articles with a laser, a non-ablative method is needed.
Lasers are not presently used to mark consumable articles. Instead, the prior proposed expedients for marking pills utilized ink, frequently the ink jet process, wherein a precisely controlled amount of an edible or inert ink material was deposited directly on the surface of the pill in a predefined pattern. The prior equipment for marking pills was large, expensive, and required high maintenance. As such, the prior equipment was inherently less than perfect and introduced a significant cost increase in the production process.
Ink marking requires precise control of the objects in order to positively and accurately deposit the ink. This is troublesome since consumable articles are very small, and they must be mass produced. Individually marking each consumable article at a cost effective rate has proven to be problematic. Production rates are limited because each article must be securely held in position relative to an ink depositing instrument. The production rate may also be undesirably reduced since each freshly marked article must not be disturbed for a particular period of time dictated by the drying requirements of the ink.
Another problem with ink marking technology is maintaining the precise location of the ink head to the article in order to apply the desired amount of ink. This is further complicated when the articles are not of a uniform size in a given batch or from batch to batch of the same or different products. A change in size or shape requires a retooling of the marking equipment. When this precise positioning is not adequately controlled, too much or too little ink may be applied, undesirably resulting in an increased scrap rate. These problems exist with ink imprinting procedures such as ink jets, stamps, rollers and the like.
Still yet another problem is that ink feed devices such as ink jet heads are inherently subject to clogging. Clogging not only increases maintenance costs, but when ink feeds clog during a marking production run, a large quantity of tablets or pills may have to be scrapped. A high scrap rate is highly undesirable.
However, one of the greatest drawbacks to utilizing ink technology to mark consumable articles is the cost associated with preparing the articles for marking. Contaminants, such as organic oils and the like, on the surface of the articles must be removed prior to marking. These contaminants undesirably reduce or eliminate legibility and durability of the ink marking. Their removal requires that special pre-treatment cleaning systems be incorporated into the process. Most pharmaceutical articles require the application of a coating of oil on their surfaces during processing, and this coating must be removed prior to marking with conventional ink techniques. Thus, in pharmaceutical applications, a special pre-treatment cleaning system is required prior to marking. The equipment used to accomplish the pre-treatment cleaning is undesirably large and expensive, and also requires high maintenance.
Given the above problems, the prior art ink based marking systems could achieve maximum production marking rates of only about 1,200 pills per minute, or 72,000 per hour.
Another drawback in utilizing ink based processes to mark consumable articles is that the ink dispenser must be close to or in direct contact with the surface of the articles to be marked. Because the prior art printing techniques required that the printing mechanism have direct access to the surfaces that were to be marked, products that had already been encapsulated in packaging materials could not be marked. It would be highly desirable to be able to mark such articles after they are encapsulated in packaging. This permits greater flexibility in production operations.
Another limitation of the prior art equipment is that the edible or inert marking material must satisfy Federal food and drug regulations. Thus, it would be very desirable to mark these articles without introducing any additional material.
When ultraviolet energy is absorbed by certain titanium dioxide containing materials, the titanium dioxide changes color. This phenomena has been successfully utilized to provide markings on various non-consumable objects such as wire insulation, electronic components, ceramics, glass, plastics, and the like. See. for instance, U.S. Pat. Nos. 5,501,827, 5,091,284, 5,415,939, 5,697,390, 5,111,523, 4,595,647, 4,753,863, 4,769,310, 5,030,551, 5,206,280, 5,773,494, 5,489,639, and 5,798,037, describe laser marking of non-consumable articles made from various materials.
Those concerned with these problems
Jagger Bruce A.
Pham Hai
Tri-Star Technologies
LandOfFree
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