Laser printers are now to be found in many offices. Discussion of the emissions from these devices has rumbled on for several years. Ink-jet printers have repeatedly been proposed as an alternative. Ink-jet printers have however been unsuitable for many commercial applications, since their printing speeds were substantially lower than those of laser printers. Since 2014, ink-jet printers have been available that constitute a serious alternative to laser printers. One model for example is able to print 100 pages per minute on one side or 50 pages per minute on both sides. The printouts are permanent in accordance with PTS standards (Papiertechnische Stiftung, Heidenau, formerly BAM) and can therefore be used by solicitors, notaries, etc. Other manufacturers have also entered this market and are now offering ink-jet printers and multi-function devices in the performance class over 30 pages per minute for commercial use.
Before now, the level of emissions from such products was not known. The "Blue Angel" environment mark applies to all types of office equipment with printing function, but was used in the past primarily for the testing of laser printers.
Following a market survey to identify the manufacturers offering ink-jet printers with high printing speeds, one product each from Brother, Epson and Hewlett Packard was procured together with the associated inks.
The inks were first analysed with regard to their chemical composition, particular attention being paid to VVOCs (very volatile organic compounds) and potentially allergenic constituents.
The emissions from the ink-jet printers were determined in accordance with the test procedure described in RAL-UZ 171, with supplementary sampling for very volatile solvents (VVOCs), since such solvents were detected in the inks. In order for the VVOC levels to be detected, a new sampling and analysis method first had to be developed.
The emissions from the products were determined in a closed test chamber both during standby and in the printing and post-printing phases; the ozone, dust, UFP, VOC and VVOC emission rates were determined.
As expected, ozone emissions were not detected on any product.
Dust-emission rates from the products of 0.3, 0.5 and 1 mg/h were measured (mean values of three measurements per product); the emission rates are thus substantially below the RAL-UZ 171 test limit value of 4 mg/h.
Ultrafine particle emissions were detected only in very small number concentrations. All printer models tested clearly meet the test requirement of 3.5 × 10exp11 particles/cm³.
VOC emissions (determined as the total volatile organic compounds, TVOC) of 0.3, 0.5 and 2.6 mg/h were measured. All TVOC values are below the test limit values of 10 mg/h (for monochrome printing) and 18 mg/h (for colour printing). The test requirements for benzene (0.05 mg/h) and styrene (1 and 1.8 mg/h for monochrome and colour printing respectively) are also observed.
VVOC emissions in the form of ethanol, acetone and i-propanol were detected. RAL-UZ 171 contains no test requirements for VVOC emissions, as a result of which these emissions cannot currently be evaluated.
As an alternative, the TVVOC and TVOC emissions of each product were added together. The totals were also below the TVOC test requirements.
To conclude, the ink-jet printers studied satisfy the emission requirements of the RAL-UZ 171 standard on the basis of which the Blue Angel mark is awarded, and emit hazardous substances at levels substantially below those from low-emission laser printers. Owing to their high printing speeds, they constitute an alternative to laser printers.
-cross sectoral-Type of hazard:
solventsDescription, key words:
Ink printer, emissions, ink, VVOC