This invention relates to improvements in the printing process involving reduction of clean-up time for ink reservoirs, minimizing environmental damage from volatile solvents.
Ink cups (also known as but not limited to reservoirs, chambers, vessels, cartridges ink wells, etc.) are used in pad printing and other applications to bring ink to the printing plate surface and the artwork image area. The liquid ink inside the cup is mixed with a volatile solvent, which evaporates at a predictable rate of speed. In the present technology, the ink cup is filled with ink. After use, the ink cup is emptied and cleaned, to be re-used later. This clean-up process involves immersing said ink cup in a solvent or emulsifier, with potentially high Volatile Organic Compound (VOC) content. The ink cup is then wiped down and stored or reused.
The clean-up process is time consuming, involving fifteen minutes to half and hour of employee time for each complete cleanup. Because of the environmental hazard of using high VOC cleaning fluids, gloves have to be worn and the area has to be ventilated.
The present technology involves significant environmental impact and a moderate amount of labor cost, especially for multiple ink cup cleanings. A method of reducing the exposure of cleaning solutions to the air and evaporation of high-VOC solvents is needed.
The present invention consists of a modified ink cup with TEFLON®-coated interior and exterior surfaces. The ink cup would be sprayed with a solution of Teflon® and the coating baked to a hard finish at or around 500 degrees Fahrenheit.
The TEFLON® coating causes the ink to bead up and drain such that the ink residue can be easily removed by rinsing and with wiping or a quick water flush. A low-VOC, green solvent, mixed with water, is all that is necessary to clean the cup interior.
In
The ink cup 101 can be made with any material that is rigid and that stands up to the baking temperature. Aluminum is the preferred embodiment for the current ink cup. Because aluminum is porous to most fluids, an aluminum ink cup 101 would normally trap ink in the pores of its interior surface. Hence, the coating 102 seals these pores and presents a smooth, non-porous interior surface to ink 103 stored in the ink cup 101.
The TEFLON® coating 102 possesses a low coefficient of friction
In the preferred embodiment, the TEFLON® coating is selected as 958-203 TEFLON® FEP for its spray-able characteristics, but other TEFLON® and other non-stick coatings can be used. TEFLON® FEP possesses a low coefficient of static friction ranging from 0.12 to 0.2, which will allow ink 103 to bead up on the sprayed interior surface 102 of the cup 101 and slide off due to the force of gravity, if nothing else. These values are from the Physics Factbook, edited by Glenn Elert.
Since surfaces coated with Teflon® coatings are both oleophobic and hydrophobic, they are not readily wetted. Cleanup is easier and more thorough—in many cases, surfaces are self-cleaning. The improvement to the present technology results in reduced clean-up time, by measurement at least three times faster. This is a significant reduction in labor cost. Low-VOC solvents mixed with water can be used and therefore exposure by employees to high-VOC solvents and emulsifiers is eliminated. This is a significant saving in environmental damage and disposal costs.
This invention has other applications, potentially, and one skilled in the art could discover these. The explication of the features of this invention does not limit the claims of this application; other applications developed by those skilled in the art will be included in this invention.
This application is a Continuation-in-Part of U.S. patent application Ser. No. 13/363,354, filed on Jan. 31, 2012, which is currently co-pending.
Number | Date | Country | |
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Parent | 13363354 | Jan 2012 | US |
Child | 14450255 | US |