June 22, 2009

Laser Printer Particle Emissions: The New Second-Hand Smoke?

By Kara Hiltz

Australian Scholars Believe Heat Generated by Laser Printers May Cause Harmful Levels of Toner Particles

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Many of us spend one-third of our lives or more in office space surrounded by copiers and laser printers, both of which use toner — the new second-hand smoke. Well, maybe that's an exaggeration but Lidia Morawska and her colleagues at the Queensland University of Technology continue to investigate a danger that may lurk in the average office — laser printer particle emissions.

Morawska Ups the Ante With a Follow-Up Study

Morawska's initial 2007 study Particle Emission Characteristics of Office Printers, created some bad blood with HP because it reported that HP LaserJet printers had among the worst emission levels.

In our 2007 interview, Morawska told us that further research was needed. She has since followed up on that promise with a new study. Her findings show that a laser printer's temperature might correlate with the amount of particles the printer emits.

In a nutshell, the researchers looked at two popular printers — an HP 2200, a "low-level" emitter, and an HP 1320n, a "high-level" emitter. The study sought to answer what comprises these particles, under what conditions do they form, and why some printers emit more particles than others.

Morawska found that high-level emitters suffer from temperature spikes between the time that paper has exited the printer and the time when a new sheet of paper enters the printer. While the paper comes in contact with the fuser during printer, it absorbs surplus heat to keep the temperature even. "Unless the printer can pre-empt this process, by reducing the power delivered to the heater before the paper is removed, the temperature must rise rapidly until a new sheet arrives to absorb the excess heat," the report explains. Otherwise, these temperature instabilities cause spikes in the amount of particle emissions.

Environmental Science & Technology published the report, An Investigation into the Characteristics and Formation Mechanisms of Particles Originating from the Operation of Laser Printers, in issue vol. 43, no. 4, 2009. (You can purchase the full report for a $30 fee.)

Similarities to Cigarette Smoke?

In some ways, the particles that laser printers emit resemble those from cigarette smoke, household appliances, or car pollution. But they also differ in very important ways.

"The indoor concentration of the particles from printer operations can reach similar levels as indoor concentration of second hand cigarette smoke or outdoor concentrations near busy roads," Morawska explains.

But laser printer particles are secondary in nature, whereas cigarette smoke and other pollutants are primary and "comprised of solid carbonaceous material." The chemistry of cigarette smoke and car pollution differs completely from laser printer particle emissions.

That's nice but what does it mean? Should we all dump our trusty laser printers?

Morawska anticipated this question and offers some practical advice. She suggests that you keep laser printers in well-ventilated areas away from where office workers sit. If your office space uses mechanical means of ventilation, like air conditioning, make sure it works at all times.

And remember, the particle emissions only occur when the printers are actually printing. If you have a home office in which you occasionally print a document, your emissions will stay low. But if you're printing one document after another in an enclosed space, you should employ adequate ventilation before your particle levels reach dangerous levels.

Too bad ventilation doesn't work as well for trans fats.

About Databazaar Blog
Virtually everyone who uses a computer uses a printer. But computers get all the glory. So we launched this blog to give printers their due. We hope you find our coverage enjoyable and useful, and encourage you to subscribe and participate.

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