The Elements of Green Pad Printing
by David Ho
KENT Engineering Co., Ltd.
KENT Engineering Co., Ltd. wrote the book on green pad printing – literally – in an effort to encourage responsible decorating practices.
How does pad printing cause pollution?
Like other forms of printing, pad printing utilizes ink, solvents, films and various kinds of chemicals. Some of these chemicals will be disposed into the water, soil and air, which eventually will pollute the environment.
Ink and cleaning solvents are by far the most serious pollutants. Ink solvents evaporate into the air from pad printers using open ink trays; one pad printer with a 150mm-wide ink tray can evaporate 5ml solvent into the air in 30 minutes. Solvents used to clean the pads or the plates can include alcohol or acetone. Environmentally friendly solvents have been developed, but arent used in all shops.
The printing plate etching process and the chemicals used also can create pollutants. Traditionally, there are three common plates used in pad printing: thick steel, thin steel and polymer. Each has a different printing life, cost and print quality. They also need different chemicals to process, including acids or alcohols used for etching, photo resist coatings and developing liquids.
What is green pad printing?
Green pad printing is an advanced printing process which employs technologies to reduce pollution, cut chemicals used, lower production cost, reduce labor, reduce rejects and increase productivity.
Green pad printing is composed of five elements.
- Green ink cup: A sealed ink cup system is able to cut 90 percent of ink solvent and cleaning solvent. There is no need to wash the Green ink cup when a color change is required. The Green ink cup has a patented plastic inner cup to hold the ink inside the aluminum cup. As a result, the ink does not come in contact with the aluminum cup, and the inner cup can be stored with a lid or disposed when changing colors.
- Green plate: Environmentally friendly laser-engraved pad printing plates have a low cost, enjoy a long life and offer high-quality prints. The use of laser engraving to etch the design onto the plate eliminates the need for acids and other chemicals.
- KCTP: The direct computer-to-plate laser engraving process eliminates the chemical etching process, films and acids. While using lasers to engrave pad printing plates is not a new process, engraving speeds have significantly increased, as has resolution quality.
- Green ink (UV ink): Green inks are not a brand from any particular manufacturer, but simply are another term used to describe UV inks. UV ink dries instantly when exposed to a UV light source and contains less than 15 percent solvent, which reduces evaporation and fights air pollution. A lower solvent ratio also allows the ink to maintain a consistent ink viscosity for a longer period of time.
- Green printer: Again, a green printer is not a specific machine model. Instead, it is a term used to describe a high-efficiency pad printing machine that consumes less energy, uses less material to build, needs fewer people to operate, achieves higher print quality and increases productivity. All printing parameters should be digitally controlled with data memory, and reject rates should be below .5 percent at all times.
Green pad printing eventually will reduce pollution, save costs and increase productivity. A pollution-controlled factory is an indication of its management, quality assurance standards and productivity.