Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
2000-03-09
2002-07-23
Crispino, Richard (Department: 1734)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S241000, C156S540000, C156S581000, C156SDIG009, C156SDIG001
Reexamination Certificate
active
06423169
ABSTRACT:
TECHNICAL FIELD
The present invention relates to the field of sublimation heat transfer systems, and more particularly to a carousel type system for, and to a related method of, transferring patterns to coatings on articles in an efficient and continuous fashion.
BACKGROUND OF THE INVENTION
Over the past several years the process of printing by sublimation, that is transforming a solid directly to a vapor, has been used to transfer decorative patterns/images to articles. In this process, sublimable inks/dyes are printed on a transfer sheet and transferred to the articles upon the application of heat and pressure. The transfer sheet is placed in direct contact with a coating on the article that is capable of receiving and retaining the pattern. When heated to a temperature at least as high as the sublimation temperature of the selected inks constituting the pattern, vaporization of the inks/pattern occurs, allowing their absorption into the coating.
Since all substances in vapor form tend to expand, a true-pattern transfer can be achieved only if the sublimated inks/patterns are captured by the heated coating instantly upon vaporization. Accordingly, steady contact between the pattern/transfer sheet and the coating/article under a constant pressure is essential for a superior quality transfer. In addition, both pressure and temperature must be uniformly distributed over the transfer surface in order to avoid blurring and distortion of the transferred pattern. Thus, the elimination of hot or cold spots and/or non-uniform contact between the pattern/transfer sheet and the coating/article is paramount.
Execution of these basic concepts have alluded the industry in the past. While there has been varying degrees of success with several single application sublimation transfer machines since the late 1980's, much is left to be desired. For example, U.S. Pat No. 4,874,454 to Talalay et al. discloses a sublimation transfer machine that utilizes a flexible heating pad that is pressed against the curved surface of a mug by an enveloping tensioning belt. Although effective in transferring the printed pattern onto the mug, the utilization of the heating pad can result in some blurring or distorting of the transferred pattern. It is believed that this problem results from hot or cold spots and/or induced sliding movement of the transfer sheet caused by the non-uniform contact between the pattern and the mug. In addition, only one article at a time may be printed.
Similarly, the device of U.S. Pat No. 4,943,684 to Kramer suffers the same shortcoming in that it is limited to a single application sublimation transfer, and it has two levered elements and corresponding heating pads which encase an article that are hard to stabilize. During the sublimation process the transfer sheet is prone to shift slightly so as to destroy the sharpness of the image.
Thus, an important aspect of the effort to improve this technology, is to provide a sublimation heat transfer system and related method capable of transferring patterns from transfer sheets to coatings on articles in a more efficient manner, while providing an emphasis on improving the quality of printed image. One aspect of improving the efficiency would be to utilize a plurality of fixtures for receiving the articles and transfer sheets to make the process continuous. Cooperating extendable plungers should be used for engaging and uniformly forcing the articles against the transfer sheets in a repeatable and consistent manner in terms of both pressure and temperature.
Additionally, the transfer system should include the loading/unloading of articles in an easy manner, and by operating in a continuous manner with the minimum of operator involvement. As a result, overall increased operating efficiency is accomplished while significantly reducing, if not eliminating, the occurrence of blurred or distorted printed articles.
SUMMARY OF THE INVENTION
Accordingly, it is a primary object of the present invention to provide a novel and improved sublimation heat transfer system and related method that are particularly adapted to provide improved operating efficiency, in order to overcome the limitations of the prior art.
Another object of the present invention is to provide a sublimation heat transfer system that is particularly adapted for transferring patterns to multiple articles in a continuous fashion.
It is yet another object of the present invention to provide a sublimation heat transfer system having a carousel for moving an article and a transfer sheet in an endless path through loading/unloading portions, and through a transfer portion where heat is applied.
Still another object of the present invention is to provide a novel and improved method of transferring a pattern from a transfer sheet to a coating on an article moving around a carousel of a sublimation heat transfer system.
Yet another object of the present invention is to provide a sublimation heat transfer system which utilizes a plurality of fixtures and plungers attached to a carousel for transferring patterns to multiple articles in a continuous fashion.
Additional objects, advantages, and other novel features of the invention will be set forth in part in the description that follows and in part will become apparent to those skilled in the art upon examination of the following or may be learned with the practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
To achieve the foregoing and other objects of the present invention as described herein, an improved sublimation heat transfer system is provided for transferring patterns from transfer sheets to coatings on one or more articles. More specifically, the sublimation heat transfer system includes a carousel for moving each article and transfer sheet in an endless path through loading/unloading portions, and through a transfer portion within an oven for heating.
A driver for the carousel imparts smooth motion to the carousel and the attached fixtures and plungers, which are arranged in groups around the periphery. The oven surrounding the carousel provides the even heat to activate the coating on the article and the ink on the transfer sheet to cause the controlled sublimation desired. As a result, the process operates in a highly efficient manner, and advantageously generates superior and sharper images on the articles.
An actuator acts to extend the plungers along the loading portion of the endless path for forcing the transfer sheets firmly against the coatings of the articles throughout the transfer portion. In accordance with an important aspect of the present intention, the transfer portion is extended a distance and the speed of the carousel is regulated to maintain the heat for a sufficient time to effect the transfer. The actuator further acts to retract the plungers along the unloading portion of the endless path for removal of the printed articles and the spent transfer sheets.
In the most preferred embodiment, the actuator for the plunger is a cam along the lower part of the oven that contacts and extends the plunger along the loading portion of the carousel's endless path. More specifically, self-aligning cam followers are attached to the plungers for contacting the cam along the loading/unloading portions. The angled mounting of the followers prevents binding of the support spindle for the plunger. Throughout the transfer portion during passage through the oven, the cam follower rides atop the cam thereby maintaining the force applied to the transfer sheets against the coatings of the articles in a consistent manner. Advantageously, in this manner both pressure and temperature are uniformly applied to the transfer sheet and articles, thus avoiding blurring or distorting of the transferred images. It has been found that hot or cold spots and non-uniform pressure between the transfer sheets and the articles is effectively eliminated.
Additionally, the fixtures are formed
Crispino Richard
Hunter Manufacturing Group, Inc.
King and Schickli PLLC
Shortsle Kevin P
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