Background Printers can release particles, which is harmful to human health. However, there is insufficient research on how printing conditions affect the level of particles released by printers.

Objective To explore the effects of different printing conditions on the level of printer-emitted particles.

Methods The experiment was carried out in a closed experimental chamber, and the changes in the number concentration of particles (size range: 0.25-32 μm) and ozone concentration in the experimental chamber during designed printing process were monitored with a portable aerosol particle size spectrometer and an ozone detector respectively. The monitoring included three parts: 2 min before printing as the background number concentration, printing 72 sheets with a designed printing task sets, and then 10 min after printing. A set of printing tasks with predetermined conditions included font, font size, single/double-sided printing mode, page layout, paper size, paper brand, and paper moisture content. The association between printing conditions and level of printer-emitted particles was evaluated by Spearman correlation analysis.

Results When printing in different fonts (Song and Kai) and different font sizes (14 points and 10.5 points), the number concentration peaks of particles in the experimental chamber were 14.71-59.35 P·cm⁻³, and there was no significant difference (P>0.05). There was no difference in the peak concentrations of printer-emitted particles between single-sided printing and double-sided printing (P>0.05), but there was a significant difference in the time of peak occurrence (P<0.05). For different page layouts, a significant difference in the peak concentrations of printer-emitted particles was found among each trisection area (P<0.05, upper 1/3> middle 1/ 3> lower 1/3). No increase in the concentration of printer-emitted particles was detected when printing with B5 paper. The peak concentration of printer-emitted particles in printing paper with varying degrees of paper moisture showed differences (P<0.05), and the concentration of particulate matter increased with the increase of moisture content (r=0.95, P<0.05). The peak area of particles was found only related to degree of paper moisture (P<0.05). There were significant differences in the emission rate of particles under different page layouts and degrees of paper moisture (P<0.05). There was no significant change of ozone concentration in the experimental chamber under different printing conditions (P>0.05).

Conclusion By changing printing conditions, the levels of printer-emitted particles are affected. Among them, page layout, paper size, and degree of paper moisture have a significant impact on the results; however, single/double-sided printing, font, font size, and paper brand have no significant impact on the results.