Wensing Michael, Schripp Tobias, Uhde Erik, Salthammer Tunga
Fraunhofer Wilhelm-Klauditz-Institute (WKI), Material Analysis and Indoor Chemistry Bienroder Weg 54E, D-38108 Braunschweig, Germany.
Sci Total Environ. 2008 Dec 15;407(1):418-27. doi: 10.1016/j.scitotenv.2008.08.018. Epub 2008 Sep 21.
The release of ultra-fine particles (UFP, d < 0.1 microm) from hardcopy devices such as laser printers into the indoor environment is currently a topic of high concern. The general emission behavior of a printer can be examined by conducting emission test chamber measurements with particle-counting devices. Chamber experiments with modified laser printers operated without toner or paper also revealed UFP emissions. On the basis of these results we reasonably doubt the opinion that UFPs primarily originate from the toner. Instead, the high-temperature fuser unit is assumed to be one source for ultra-fine particle emission. UFP release typically follows the flow path of the cooling air which may leave the printer casing at various points (e.g. the paper tray). This limits the usability of the commercial filter systems available because the released particles could leave the printer without passing through the filter. Chamber measurements with various filter systems retrofitted to a laser printer demonstrate different efficiencies of UFP reduction. Complementary experiments were carried out in an office room. Here the decay of the particle concentration after a print job was about ten times slower than in the test chamber. A toxicological assessment of the emitted particles requires that their chemical composition be known. Due to the low mass of the released UFPs chemical analysis needs a prior enrichment on a feasible media. Experiments using electrostatic precipitation showed a flame retardant (tri-xylyl phosphate) whose concentration on the media was dependent on the number of pages printed. Whether this compound was particle-bound could not be determined.
诸如激光打印机等硬拷贝设备向室内环境释放超细颗粒（UFP，直径<0.1微米）目前是一个备受关注的话题。打印机的一般排放行为可通过使用颗粒计数设备在排放测试室进行测量来检验。对未使用碳粉或纸张运行的改良激光打印机进行的测试室实验也显示了超细颗粒排放。基于这些结果，我们有理由怀疑超细颗粒主要源自碳粉这一观点。相反，高温定影单元被认为是超细颗粒排放的一个来源。超细颗粒的释放通常遵循冷却空气的流动路径，冷却空气可能在不同位置（如纸盒）离开打印机外壳。这限制了现有商用过滤系统的可用性，因为释放出的颗粒可能未经过滤网就离开打印机。对安装了各种过滤系统的激光打印机进行的测试室测量表明了不同的超细颗粒减排效率。在办公室进行了补充实验。在这里，打印作业后颗粒浓度的衰减比在测试室中慢约十倍。对排放颗粒进行毒理学评估需要了解其化学成分。由于释放出的超细颗粒质量低，化学分析需要先在可行的介质上进行富集。使用静电沉淀的实验显示了一种阻燃剂（磷酸三苯酯），其在介质上的浓度取决于打印的页数。无法确定该化合物是否与颗粒结合。
