Toner

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Black toner container Toner-container-black-0a.jpg
Black toner container
Colored toner container Toner.jpg
Colored toner container

Toner is a powder mixture used in laser printers and photocopiers to form the printed text and images on the paper, in general through a toner cartridge. Mostly granulated plastic, early mixtures only added carbon powder and iron oxide, however, mixtures have since been developed containing polypropylene, fumed silica, and various minerals for triboelectrification. [1] Toner using plant-derived plastic also exists as an alternative to petroleum plastic. [2] Toner particles are melted by the heat of the fuser, and are thus bonded to the paper.

Contents

In earlier photocopiers, this low-cost carbon toner was poured by the user from a bottle into a reservoir in the machine[ citation needed ]. Later copiers, and laser printers from the first 1984 Hewlett-Packard LaserJet, [3] feed directly from a sealed toner cartridge.

Laser toner cartridges for use in color copiers and printers come in sets of cyan, magenta, yellow and black (CMYK), allowing a very large color gamut to be generated by mixing.

Composition, size and manufacture

The specific polymer used varies by manufacturer but can be a styrene acrylate copolymer, a polyester resin, a styrene butadiene copolymer, or a few other special polymers. Toner formulations vary from manufacturer to manufacturer and even from machine to machine. Typically formulation, granule size and melting point vary the most.

Originally, the particle size of toner averaged 14–16 micrometres [4] or greater. To improve image resolution, particle size was reduced, eventually reaching about 8–10 micrometers for 600 dots per inch resolution.[ citation needed ] Further reductions in particle size producing further improvements in resolution are being developed through the application of new technologies such as Emulsion-Aggregation. [5] Toner manufacturers maintain a quality control standard for particle size distribution in order to produce a powder suitable for use in their printers.

Toner has traditionally been made by compounding the ingredients and creating a slab which was broken or pelletized, then turned into a fine powder with a controlled particle size range by air jet milling. This process results in toner granules with varying sizes and aspherical shapes. To get a finer print, some companies are using a chemical process to grow toner particles from molecular reagents. [6] This results in more uniform size and shapes of toner particles. The smaller, uniform shapes permit more accurate colour reproduction and more efficient toner use.

Clean-up

Toner can be washed off skin and garments with cold water. Hot or warm water softens the toner, causing it to bond in place. Toner fused to skin eventually wears off, or can be partially removed using an abrasive hand cleaner. Toner fused to clothing usually cannot be removed. Unfused toner is easily cleaned from most water-washable clothing. Because toner is a wax or plastic powder with a low melting temperature it must be kept cold while cleaning.

Toner particles have electrostatic properties by design and can develop static-electric charges when they rub against other particles, objects, or the interiors of transport systems and vacuum cleaner hoses. Because of this and the small particle size, toner should not be vacuumed with a conventional home vacuum cleaner. Static discharge from charged toner particles theoretically may ignite dust [7] in the vacuum cleaner bag or create a small explosion if sufficient toner is airborne. Toner particles are so fine that they are poorly filtered by household vacuum cleaner filter bags and can blow through the vacuum motor into the room. So they also can cause overheating by clogging the motor filter and short circuit by their electric conductivity (carbon, iron) when they melt inside the motor. [8]

If toner spills into the laser printer, a special type of vacuum cleaner with an electrically conductive hose and a high efficiency (HEPA) filter may be needed for effective cleaning. These are called electrostatic discharge-safe (ESD-safe) or toner vacuums. Similar HEPA-filter equipped vacuums should be used for clean-up of larger toner spills.

Health risks

Muhle et al. (1991) reported that the responses to chronically inhaled copying toner, a plastic dust pigmented with carbon black, titanium dioxide and silica, were also similar qualitatively to titanium dioxide and diesel exhaust. [9]

Carbon black, one of the components of toner, is classified as "possibly carcinogenic" (Group 2B) by the IARC.

As a fine powder, toner can remain suspended in the air for some period, and is considered to have health effects comparable to inert dust. It can be an irritant to people with respiratory conditions such as asthma or bronchitis. Following studies on bacteria in the 1970s that raised concerns about health effects resulting from pyrrole, a contaminant created during manufacture of the carbon black used in black toner, manufacturing processes were changed to eliminate pyrrole from the finished product.

Research by the Queensland University of Technology has indicated that some laser printers emit submicrometer particles which have been associated in other environmental studies with respiratory diseases. [10]

A study at the University of Rostock has found that the microscopic particles in toner are carcinogenic, similar to asbestos. Several technicians who had been working with printers and copiers on a daily basis were observed for several years. They showed increased lung problems. [11] This confirms previous research published in 2006. [12]

Research at Harvard University has shown that, during printing, metal-oxide nanoparticles (defined as 100 nanometres and smaller, hence 0.1 micrometres and smaller) are released into the air from toner-based laser printers and multifunction devices. These machines use toner particles that are on average 20 micrometres in overall diameter, but the surfaces of the toner particles themselves carry innumerable tiny metal-oxide nanoparticles. [13] These ultra-small metal-oxide nanoparticles are highly bioactive and could cause harm to the lungs and also elsewhere in the body, given that particles 0.1 micrometres and smaller can cross biological membranes (including lung alveoli), thereby gaining access to all organs via blood circulation. [14] This remains an area of active research, with many knowledge gaps. [15] [16]

Packaging

The toner cartridge is a kind of toner container, that is also a consumable component of the printer. Tonerkassette Laserdrucker HP.jpg
The toner cartridge is a kind of toner container, that is also a consumable component of the printer.

The toner container can be a simple pack, for toner storage and transportation, or further, a consumable component of the printer. The most common way to consume toner is with a toner cartridge (or laser toner), as an office supply of a laser printers.

Repackaging

Several toner manufacturers offer toner in wholesale quantities. Typically, bulk loose toner is sold in barrels or 10 kg (22-pound) bags.

Toner is then used by a variety of industries in order to provide consumers with a finished laser toner cartridge.

Original Equipment manufacturers such as HP and Canon as well as manufacturers of compatible toner cartridges use the toner in the process of manufacturing a brand new OEM cartridge. Remanufacturers [17] of toner cartridges use the bulk toner in the process of creating remanufactured toner cartridges. Other companies use the toner to provide a toner refill service.

Most toner cartridges are available to the average consumer through retail outlets or local remanufacturing operations. Remanufactured and refilled toner cartridges are generally offered at a lower cost than original toner cartridges, having been either wholly remanufactured and then refilled with toner (the more-optimal method) or just refilled with toner (the less-optimal method)..

Environmental considerations

Recycling of pre-consumer waste toner is practiced by most manufacturers. Classifying toner to the desired size distribution produces off-size rejects, but these become valuable feedstocks for the compounding operation, and are recycled this way. Post-consumer waste toner appears primarily in the cleaning operation of the photo-printing machine. In early printers, as much as 20 to 25% of feed toner would wind up in the cleaner sump and be discarded as waste. Improved printer efficiencies have reduced this waste stream to lower levels, although on average 13% of the toner in each cartridge is still wasted. [18] Some printer designs have attempted to divert this waste toner back into the virgin toner reservoir for direct reuse in the printer; these attempts have met with mixed success as the composition of the toner will change by expending fusibles while retaining developer particles. Some consideration and fewer industry attempts have been made to reclaim waste toner by cleaning it and "remanufacturing" it.

Most toner goes to printed pages, a large fraction of which are ultimately recycled in paper recovery and recycling operations. Removal of toner from the pulp is not easy, and toner formulations to ease this step have been reported. [19] Hydrolyzable, water-soluble, and caustic-soluble toner resins have been reported, but do not appear to enjoy widespread application. Most paper recycling facilities mix toner with other waste material, such as inks and resins, into a sludge with no commercial use.

In the UK, large compatible ink cartridge manufacturers like Jet Tec & Dubaria have implemented toner recycling programs in order to receive back empty cartridges for refilling of HP, Lexmark, Dell, etc. cartridges, as no compatible version is readily available.

Toner-modified asphalt binder

Since toner consists of several copolymers and it is a carbon-based material, it can be used as a useful modifier for the asphalt industry. It has been shown that inclusion of left-over burnt toner enhances the rheological and mechanical properties of asphalt binder, significantly. Such an application can be placed as an environmentally friendly alternative to prevent soil contamination due to the landfilling of waste toner. [20] Adding waste toner into asphalt binder and mixture decreases the binder's glass transition temperature and also, in the meantime increase the crystallization temperature as well. [21] [22]

Related Research Articles

Laser printing Electrostatic digital printing process

Laser printing is an electrostatic digital printing process. It produces high-quality text and graphics by repeatedly passing a laser beam back and forth over a negatively charged cylinder called a "drum" to define a differentially charged image. The drum then selectively collects electrically charged powdered ink (toner), and transfers the image to paper, which is then heated in order to permanently fuse the text, imagery, or both, to the paper. As with digital photocopiers, laser printers employ a xerographic printing process. Laser printing differs from traditional xerography as implemented in analog photocopiers in that in the latter, the image is formed by reflecting light off an existing document onto the exposed drum.

Inkjet printing Type of computer printing

Inkjet printing is a type of computer printing that recreates a digital image by propelling droplets of ink onto paper and plastic substrates. Inkjet printers are the most commonly used type of printer, and range from small inexpensive consumer models to expensive professional machines.

Xerography Dry photocopying technique

Xerography is a dry photocopying technique. Originally called electrophotography, it was renamed xerography—from the Greek roots ξηρός xeros, "dry" and -γραφία -graphia, "writing"—to emphasize that unlike reproduction techniques then in use such as cyanotype, the process of xerography used no liquid chemicals.

Nanomaterials Materials whose granular size lies between 1 to 100 nm

Nanomaterials describe, in principle, materials of which a single unit small sized between 1 and 100 nm.

An electrofax involved electrostatic printer and copier technology, where an image was formed directly on the paper, instead of first on a drum, then transferred to paper, as it would be in xerography. It was used in the United States from the 1950s through the 1980s.

Nanoparticle Particle with size less than 100 nm

A nanoparticle or ultrafine particle is usually defined as a particle of matter that is between 1 and 100 nanometres (nm) in diameter. The term is sometimes used for larger particles, up to 500 nm, or fibers and tubes that are less than 100 nm in only two directions. At the lowest range, metal particles smaller than 1 nm are usually called atom clusters instead.

Nanostructure

A nanostructure is a structure of intermediate size between microscopic and molecular structures. Nanostructural detail is microstructure at nanoscale.

Nano-thermite or super-thermite is a metastable intermolecular composite (MICs) characterized by a particle size of its main constituents, a metal and a metal oxide, under 100 nanometers. This allows for high and customizable reaction rates. Nano-thermites contain an oxidizer and a reducing agent, which are intimately mixed on the nanometer scale. MICs, including nano-thermitic materials, are a type of reactive materials investigated for military use, as well as for general applications involving propellants, explosives, and pyrotechnics.

Ink cartridge

An ink cartridge or inkjet cartridge is a component of an inkjet printer that contains the ink that is deposited onto paper during printing.

Reuse Using an item again after it has been used, instead of recycling or disposing

Reuse is the action or practice of using an item, whether for its original purpose or to fulfil a different function. It should be distinguished from recycling, which is the breaking down of used items to make raw materials for the manufacture of new products. Reuse – by taking, but not reprocessing, previously used items – helps save time, money, energy and resources. In broader economic terms, it can make quality products available to people and organizations with limited means, while generating jobs and business activity that contribute to the economy.

Compatible ink is manufactured by third party manufacturers and is designed to work in designated printers without infringing on patents of printer manufacturers. Compatible inks and toners may come in a variety of packaging including sealed plastic wraps or taped plastic wraps. Regardless of packaging, compatible products are generally priced lower than original equipment manufacturer (OEM) brand inks and toners.

Dynamic Cassette International (DCI) is an internationally recognised Boston, Lincolnshire, UK based ink cartridge and laser toner manufacturing company, producing products under the Jet Tec brand name. DCI is the sole UK manufacturer of compatible ink cartridges. DCI is notable for winning the Queen's Award for Enterprise: Innovation in 2004 and the Queen's Award for Export and being one of the biggest employers in Boston, employing over 300 staff at its 40,000 square metres factory. The company is currently Europe's largest manufacturer of compatible inkjet cartridges and has a turnover in excess of £20 million.

Toner refill

Toner refilling is the practice of refilling empty laser printer toner cartridges with new toner powder. This enables the cartridge to be reused, saving the cost of a complete new cartridge and the impact of the waste and disposal of the old one.

Photocopier Device for reproducing documents

A photocopier is a machine that makes copies of documents and other visual images onto paper or plastic film quickly and cheaply. Most modern photocopiers use a technology called xerography, a dry process that uses electrostatic charges on a light-sensitive photoreceptor to first attract and then transfer toner particles onto paper in the form of an image. The toner is then fused onto the paper using heat, pressure, or a combination of both. Copiers can also use other technologies, such as ink jet, but xerography is standard for office copying.

Nano spray dryer

Nano spray dryers refer to using spray drying to create particles in the nanometer range. Spray drying is a gentle method for producing powders with a defined particle size out of solutions, dispersions, and emulsions which is widely used for pharmaceuticals, food, biotechnology, and other industrial materials synthesis.

Toner cartridge

A toner cartridge, also called laser toner, is the consumable component of a laser printer. Toner cartridges contain toner powder, a fine, dry mixture of plastic particles, carbon, and black or other coloring agents that make the actual image on the paper. The toner is transferred to paper via an electrostatically charged drum unit, and fused onto the paper by heated rollers during the printing process. It will not stain like ink cartridges, but it can get messy if handled improperly.

Products made from a variety of materials can be recycled using a number of processes.

Micronized rubber powder (MRP) is classified as fine, dry, powdered elastomeric crumb rubber in which a significant proportion of particles are less than 100 µm and free of foreign particulates. MRP particle size distributions typically range from 180 µm to 10 µm. Narrower distributions can be achieved depending on the classification technology.

Remax World Expo

The RemaxWorld Expo is an annual trade show comprising vendors from within the print consumables industry. The event began in 2007, resulting from a joint venture between the China Council for the Promotion of International Trade (CCPIT) and Recycling Times Media Corporation. Centered in Zhuhai, widely recognized as being the print consumables capital of the world, the exhibition currently takes place in the newly constructed Zhuhai International Convention & Exhibition Center. In 2015, the show accommodated 463 exhibitors and 13,938 visitors from 83 countries.

Katun is a supplier of OEM-compatible imaging consumables and supplies for office equipment. Katun designs, manufactures, sells, and distributes OEM-compatible imaging products for copiers, printers, and other imaging equipment worldwide.

References

  1. Simmons, Lee. "Inside Laser Printer Toner: Wax, Static, Lots of Plastic". WIRED.
  2. . The US Environmental Protection Agency https://rechargermag.com/articles/67765/.Missing or empty |title= (help)
  3. "HP Virtual Museum: Hewlett-Packard LaserJet printer, 1984". Hp.com. Retrieved 28 January 2016.
  4. Nakamura, Y.; Kutsuwada, N. (October 1–5, 1989). "Direct measurement of toner particle size". Industry Applications Society Annual Meeting, 1989. pp. 2239–2242. doi:10.1109/IAS.1989.96951.
  5. Mahabadi, Hadi; Stocum, Anne (2006-08-01). "Xerox's Emulsion Aggregation Toner – An Environmentally Friendly Technology" (PDF). Xerox . Archived from the original (PDF) on 2007-09-28. Retrieved 2007-08-03.
  6. "Chemically Prepared Toner" (PDF). Galliford Consulting. 2006. Archived from the original (PDF) on 2006-10-15.
  7. Robert Zalosh (2009). "Dust Explosion Fundamentals: Ignition Criteria and Pressure Development" (PDF). National Fire Prevention Association. pp. 7, 8.
  8. "Step By Step 16 - Preventative Maintenance". Dan's Data.
  9. "11.6 metals" (PDF).
  10. Morawska, Lidia; He, Congrong; Taplin, Len (2007-07-10). "Particle Emission Characteristics of Office Printers" (PDF). International Laboratory for Air Quality and Health (Queensland University of Technology); Queensland Department of Public Works. SF Gate. pp. 1–7. Retrieved 2007-08-03.
  11. "Laut Studie kann Tonerstaub Krebs verursachen" [Toner dust can cause cancer, according to study]. Berliner Morgenpost (in German). Retrieved 2017-08-06.
  12. Ewers, U.; Nowak, D. (2006). "Gesundheitsschäden und Erkrankungen durch Emissionen aus Laserdruckern und Kopiergeräten?" [Health hazards caused by emissions of laser printers and copiers?](PDF). Gefahrstoffe – Reinhaltung der Luft (in German). Dusseldorf: Springer. 66 (5): 203–210. ISSN   0949-8036.
  13. Powell, Alvin. At Harvard Chan School, nano safety is no small concern (interview with Philip Demokritou, October 24, 2018). https://news.harvard.edu/gazette/story/2018/10/at-harvard-chan-school-nano-safety-is-no-small-concern/ Accessed February 6 2020.
  14. Pirela, Sandra V. et al. Engineered nanoparticles emitted from laser printers: Quantifying the health implications from nano-enabled products during consumer use. Quantifying Potential Acute and Chronic Exposure from 3D Printing/Additive Manufacturing (Conference presentation October 9 2018). https://www.nano.gov/sites/default/files/achievements/Pirela_1.pdf Accessed February 6 2020.
  15. Pirela, Sandra V.; Martin, John; Bello, Dhimiter; Demokritou, Philip (2017). "Nanoparticle exposures from nano-enabled toner-based printing equipment and human health: State of science and future research needs". Critical Reviews in Toxicology. 47 (8): 678–704. doi:10.1080/10408444.2017.1318354. PMC   5857386 . PMID   28524743.
  16. Pirela, Sandra V.; Sotiriou, Georgios A.; Bello, Dhimiter; Shafer, Martin; Bunker, Kristin Lee; Castranova, Vincent; Thomas, Treye; Demokritou, Philip (11 November 2014). "Consumer exposures to laser printer-emitted engineered nanoparticles: A case study of life-cycle implications from nano-enabled products". Nanotoxicology. 9 (6): 760–768. doi:10.3109/17435390.2014.976602. PMC   4671491 .
  17. "Whitepaper - Managing the cost of printing and copying". tonerguy.net. Gunn Trading Ltd. 2015. Retrieved 16 May 2015.
  18. "Asphalt mix made with recycled printer toner paves way for eco-friendly roads". The Guardian. 2015-05-20. Retrieved 2015-09-17.
  19. Kittelberger, Steve and Sacripante, Guerino, "Easily deinkable toner: A solution to the deinking problem for small mills". Pulp & Paper Canada. 104:5, (2003) p.37.
  20. Notani, M. A., & Mokhtarnejad, M. (2018). Investigating the rheological and self-healing capability of toner-modified asphalt binder. Proceedings of the Institution of Civil Engineers-Construction Materials, 1-9.
  21. Notani, M. A., Moghadas Nejad, F., Fini, E. H., & Hajikarimi, P. (2019). Low-Temperature Performance of Toner-Modified Asphalt Binder. Journal of Transportation Engineering, Part B: Pavements, 145(3), 04019022.
  22. Notani, M. A., Moghadas Nejad, F., Khodaii, A., & Hajikarimi, P. (2018). Evaluating fatigue resistance of toner-modified asphalt binders using the linear amplitude sweep test. Road Materials and Pavement Design, 1-14.