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ISO/IEC 28360-2: Information Technology — Office Equipment — Chemical Emission from Printers
Specialized emission testing protocols for printers, copiers, and multifunction printing devices
ISO/IEC 28360-2 specifically addresses chemical emission measurement for printing and imaging equipment, building upon the general framework established in Part 1. Printers present unique emission challenges due to their complex mechanical and thermal processes: laser printers generate ozone through corona charging, toner particles are released during fusing and paper handling, and inkjet printers emit volatile compounds from ink formulations. This standard provides tailored testing protocols that capture the distinctive emission profiles of different printing technologies.
Part 2 is indispensable for printer manufacturers, office furniture designers, and facility ventilation engineers. Understanding the specific emission characteristics of different printing technologies enables targeted mitigation strategies — such as localized exhaust ventilation for laser printers in high-volume printing environments.
Printer-Specific Emission Test Setup
The standard establishes printer-specific test conditions that reflect realistic usage patterns. For laser printers, the test protocol requires measurement of ozone during continuous printing operations, as corona discharge from the charging roller and transfer roller generates ozone as a byproduct. Toner particle emissions are collected using cascade impactors that separate particles by aerodynamic diameter, enabling size-distribution analysis of ultrafine, fine, and coarse fractions.
For inkjet printers, the focus shifts to VOC emissions from ink formulations, particularly glycol ethers, 2-pyrrolidone, and other solvents used in aqueous and solvent-based inks. The standard specifies print patterns with varying ink coverage to capture the relationship between ink usage and emission rates. Fixative and maintenance cartridge compounds are also analyzed during cleaning cycles.
| Printer Type | Primary Emissions | Key Measurement Parameters | Typical Test Duration |
|---|---|---|---|
| Laser monochrome | Ozone, ultrafine particles, VOCs from toner | Ozone concentration, particle count (10-400 nm), VOC profile | 4-6 hours continuous printing |
| Laser color | Same as monochrome + color toner VOCs | Same + color-specific VOC markers | 6-8 hours mixed print jobs |
| Inkjet (aqueous) | Glycol ethers, 2-pyrrolidone, humectants | VOC concentration, aerosol particle distribution | 4-8 hours intermittent printing |
| Inkjet (solvent) | Cyclohexanone, MEK, aromatic solvents | Solvent vapor concentration, VOC speciation | 6-8 hours continuous printing |
| Multifunction (all-in-one) | Combined emissions from print + scan + copy | All parameters across all operating modes | 8-12 hours full operational cycle |
Ozone measurement requires particular attention: the half-life of ozone in test chambers is relatively short (minutes), and sampling lines must be constructed from ozone-inert materials such as PTFE or stainless steel. Ozone reacts readily with chamber walls and other compounds, so real-time measurement using UV photometric or electrochemical sensors is preferred over integrated sampling methods to capture peak concentrations accurately.
Toner Particle Characterization and Exposure Assessment
ISO/IEC 28360-2 provides detailed methods for characterizing toner particle emissions, which are of particular health concern due to their ultrafine size fraction. Laser printers emit particles predominantly in the 30-100 nanometer range during printing operations, with peak emissions occurring during the fusing phase when toner is thermally bonded to paper. The standard specifies particle counting using condensation particle counters (CPCs) and scanning mobility particle sizers (SMPS) to capture the full size distribution.
Chemical characterization of toner particles includes analysis of trace metals (iron, chromium, manganese), carbon black content, and polymer binder composition. The standard references ISO 21501 for particle counter calibration and ISO 15900 for differential electrical mobility analysis of aerosol particles. Exposure assessment calculations incorporate deposition fractions in the human respiratory tract using the International Commission on Radiological Protection (ICRP) lung deposition model.
The particle measurement protocols in ISO/IEC 28360-2 have enabled significant advances in printer emissions research. Studies using these standardized methods have demonstrated that modern low-emission printers can reduce ultrafine particle emissions by 80-90% compared to conventional models, through design improvements including optimized fuser temperature profiles, enhanced corona shielding, and integrated filtration systems.
Emission Mitigation and Product Certification
The standard facilitates comparative evaluation of printer emissions for product certification and procurement decisions. Blue Angel certification for printers (DE-UZ 171 and DE-UZ 205) directly references ISO/IEC 28360-2 for emission testing requirements. The certification sets maximum allowable emission rates for ozone, TVOC, and particles, with the strictest limits applying to devices intended for use in occupied office spaces.
Engineering mitigation strategies validated through this standard’s test methods include: optimized corona roller materials that reduce ozone generation by 60-70%, integrated carbon filters for internal air recirculation, low-fusing-temperature toner formulations that reduce thermal decomposition products, and encapsulation technologies that bind toner particles more effectively to paper during the printing process.
| Mitigation Strategy | Technology Approach | Emission Reduction | Implementation Considerations |
|---|---|---|---|
| Ozone reduction | Catalytic ozone converters, corona optimization | 60-80% ozone reduction | Converter maintenance interval, cost increase |
| Particle filtration | HEPA or electrostatic internal filters | 70-90% particle reduction | Filter replacement cycle, airflow resistance |
| Low-emission toner | Reduced fusing temperature, polymer optimization | 40-60% VOC reduction | Print quality validation, compatibility testing |
| Encapsulation | Improved toner-to-paper fixation | 50-70% particle reduction | Fuser durability, energy consumption |
| Ventilation integration | Direct exhaust connection for high-volume printers | 90%+ exposure reduction | Building HVAC integration, installation cost |
The health implications of chronic exposure to printer emissions should not be underestimated. Multiple epidemiological studies have linked occupational exposure to laser printer emissions with increased prevalence of respiratory symptoms, particularly among office workers with pre-existing conditions such as asthma. Never locate high-volume printers in unventilated enclosed spaces or near individual workstations without adequate localized exhaust ventilation.
When specifying printers for low-emission certification programs, request documentation of ISO/IEC 28360-2 compliance including the specific emission test report. Pay attention to the operational mode that triggers peak emissions — some printers have a “quiet mode” or “draft mode” that reduces emissions but at the cost of print speed or quality. Choose devices that meet emission limits under normal operating conditions, not just in a reduced-performance mode.
Frequently Asked Questions
Q: Are inkjet printers safer than laser printers in terms of chemical emissions?
A: The answer depends on the specific emission profile. Laser printers primarily emit ultrafine particles and ozone during printing, while inkjet printers emit VOCs from ink solvents. For most office environments, modern inkjet printers have lower overall health impact because their emissions are dominated by relatively low-toxicity glycol ethers and do not include ultrafine particles. However, solvent-based inkjet printers used in wide-format printing can emit significant VOC levels. The safest approach is to select devices certified to low-emission standards regardless of printer type.
Q: How long do printer emissions persist in office air after a print job?
A: Ultrafine particles from laser printers decay rapidly through coagulation and deposition, with concentrations typically returning to background levels within 15-30 minutes after printing stops. Ozone decays even more quickly due to its reactivity, with a half-life of minutes in typical indoor environments. VOCs from both laser and inkjet printers can persist longer, with some compounds remaining detectable for several hours, particularly in spaces with low ventilation rates.
Q: What is the relationship between print coverage and emission rates?
A: Emission rates generally increase with print coverage, but the relationship is not always linear. For laser printers, toner particle emissions plateau at medium coverage levels due to saturation effects in the fusing process. Ozone generation is more closely related to the number of pages printed per minute than to coverage density. For inkjet printers, VOC emissions show a more linear relationship with ink consumption, as the majority of emitted VOCs come from the ink drying process. ISO/IEC 28360-2 specifies standard test patterns at 5% and 20% coverage for comparability.
Q: Can aftermarket or refilled toner cartridges affect emission profiles?
A: Absolutely. Third-party toner formulations can produce significantly different emission profiles compared to original equipment manufacturer (OEM) toner. Differences in particle size distribution, polymer composition, and additive packages can increase emissions by 2-5 times in some cases. ISO/IEC 28360-2 testing conducted with OEM consumables may not represent emissions when using aftermarket supplies. Organizations concerned about indoor air quality should verify emission performance with the specific consumables they intend to use.
