Solvent printing was a godsend to the wide-format printing industry. While it would be a boon for the outdoor-durable print, it would bring its own set of health and environmental issues. The early solvent inks were just short of running uranium through the printer; just ask anyone who went to a trade show in the early part of this century and had an opportunity to breathe in the fumes. But since the introduction of solvent inks, the formulations have evolved to be less noxious, smelly, and flammable.
Though many of these newer solvents are milder, and are sometimes referred to with the misnomer eco, they still contain ingredients that can be harmful to those who operate them. If you check the Material Safety Data Sheets (MSDS) for substances that are potentially harmful to humans, including carcinogens, you needn’t look far. But never fear, since the effects of solvent fumes and outgassing can be greatly mitigated by taking the appropriate steps. Moreover, you can do the environment a favor by taking proper care in the disposal of your ink waste.
Step one is to know your ink. Is it a strong or mild solvent? This is important, because a strong solvent requires stronger measures. With strong solvents, a ventilation system attached to the printer that vents outside is a must. Most strong solvent printers either come with their own ventilation kit, or it’s an option. Basically, the printer needs to be a closed system that vents fumes outside the building and does not allow the fumes to escape into the production area or into the ventilation system.
If your operation is in a multi-tenant shopping center, for instance, and the printer’s fumes end up in the ventilation system, you’re sure to have some unhappy neighbors. To ensure venting is done properly, you should be familiar with local codes and regulations, and enlist the services of a professional in the HVAC business. This type of closed system is the ideal, even for mild solvent printers. If it can be done, it should, though there are other, simpler options for mild solvent printers. Though mild solvents are milder, they still have hazardous ingredients.
And, just because one solvent smells less than another, it doesn’t mean it’s milder. The less-smelly solvent may have masking agents to keep the smell down, so you can’t always trust your nose, but you can usually trust the MSDS. The key indicator regarding the solvent’s relative strength is the flash point. The flash point measures the temperature at which the ink becomes flammable. The lower the flash point, the more volatile the formulation, and the stronger the solvent is.
First, and at the very least, barring any type of ventilation or air-cleaning system, the printer should be near an open door or window so that the fumes aren’t concentrated in an enclosed area. But it’s strongly recommended that you employ some type of air cleaning and filtration system. Abatement Technologies manufactures the Predator 600, which utilizes a true HEPA (high efficiency particulate air filter) system. This will take care of a lot of the harmful VOCs (volatile organic compounds), while cutting down significantly on the solvent smell.
An air filter/scrubber like the Predator should be situated close to the printer so that it can capture as many of the fumes as possible. Ideally, the finishing area should either be very close to the printer and the filter, or have its own filter since solvent prints that are drying continue to outgas the VOCs, creating their own set of fumes. This is also why you should allow solvent prints to dry for at least 24 hours before lamination and application; if the print is still outgassing when you laminate, it will increase the likelihood of failure in the field.