Toner

Toner, the colorant used in copiers and laser printers, particularly for producing a printing image on a printing material (usually paper ).

• 2.1 component toner
• 2.2 Two -component toner
• 2.3 Transfer liquid

• 3.1 application to the medium
• 3.2 Transfer Technology

• 4.1 Cleanliness
• 4.2 Environmental aspects
• 4.3 Hazards to humans
• 4.4 Disposal and Recycling

Properties

Composition

Toner is a fine powder of 5 to 30 micron size particles. Due to the very small particle size of the powder is free-flowing and behaves much like a liquid. It is composed of a synthetic resin, pigments, metal oxides elektrisierbaren and excipients.

Requirements

The requirements imposed on the toner is very high. Firstly, it must meet the requirements with respect to the print result - including deep blacks and fine as possible graduation without dirt effect. The plastic job should be low, on the other hand is to adhere to as many materials of toner, just not in the device itself ( fuser rollers ). It must be the technical requirements of the instrument justice, may not accept moisture and must remain constant in its consistency until use.

Toner types

Component toner

It is used in virtually all systems in which the toner is accommodated in a cartridge to be replaced as an entire unit. The toner is mixed with a developer which is a rotating magnet to a tube, the so-called developing roller, toner is required to establish a so-called brush. This brush touches the photoconductor drum, and out of the toner particles migrate during the copy process on the photoconductor drum. The advantage of easy maintenance (to replace a single cartridge) is offset by the higher price of the toner. Since the developer must also remain on the medium to be printed, this shall not distort the colors, which is why it is expensive.

Dual component toner development

In two-component toner developer, and the actual toner are separated. As a developer, are usually very fine iron particles used are not applied to the paper and thus not consumed. Used two-component toner especially in copiers and digital presses. Devices of this type are considerably more complex, but the benefits justify it especially with larger devices. The toner must take on any special properties of the developer of consideration, is more simple and therefore more cost effective.

Transfer liquid

A transfer fluid, erroneously often called liquid toner, contains the actual dispersed ink particles. The exposed drum rotates through this transfer liquid and toner particles does, on. The quality of the print is higher because the toner particles have partially less than 1 micron size (see: HP Indigo technology ).

Transfer fluids require no subsequent fixation.

Processing

Application to the medium

After application to the charged with about 5 kV photoconductor drum, the toner particles are transferred by electrical forces on the more loaded, running past to the photoconductor drum paper and then fused solid from a heating roller / fixed ( electrophotography ).

Transfer technique

Since toner is fused by heat on the paper, you can solve it with heat. This behavior makes you look at the so-called toner transfer method advantage. This is usually printed on special films or papers on which the toner does not adhere too tight. After printing, the toner image of this support can using an iron or laminator on T -shirts, metal plates (eg signs ) or even copper-clad boards are transferred.

Handling

Cleanliness

Toner has a strong dirt effect, which is why it is usually sold in the form of mono-component in closed units (toner cartridges). For cleaning of laser printers, copiers, etc. using special toner vacuum cleaner that can retain both the fine toner particles and an electrostatic charge (and thus prevent any damage to be cleaned equipment) prevent.

Environmental aspects

Toner is not a harmless substance, as long as it was not fused to the paper. According to Öko-Test can toners produced in fixing based on synthetic resin ( styrene -acrylate copolymer ) can be released by heat and pressure of styrene ( a suspected carcinogen ) and possibly small amounts of benzene ( carcinogen ). Furthermore, among the established connections increased amounts of dibutyltin were noted, which has a hormone-like effect in humans and animals. Also the toxic tributyltin (TBT) was detected in trace amounts. The investigation methods of eco- test are drawn from the magazine c't in doubt. In particular, the point was made that only two printers were investigated in detail and it just sections the printer well tested as particularly harmful from the c't due to high ozone emissions.

Hazard for humans

Toner caused particulate matter and is to be harmful in reputation. Measurements of toner dust emissions from laser printers and copiers by the BG Institute for Occupational Safety showed that the concentration values ​​are even under unfavorable conditions well below the general dust limit value (A- fraction) of 3 mg / m³. Nevertheless, one should not be too careless when handling toner, because the fine particles that make up the toner, are so small that they can pass freely through the filters and protective function of the lung in part and thus pass into the body. The filter of vacuum cleaners can not hold back the fine particles. Vacuum cleaner by the toner particles are distributed only in the air or in space.

Disposal and recycling

The Waste Act requires environmentally sound disposal. In addition, manufacturers are required to empty toner cartridges for disposal back free of charge. This can be done, for example, they give the dealer 's or return it to the manufacturer. There is also the option of filling toner cartridges with refill toner new, to avoid the disposal of all. Various companies specialize in this work and buy empty toner cartridges at prices from 10 cents to 5 Euros per piece and sell them after filling, replacement of worn parts and test as so-called Rebuilttoner. This is classified as ecologically and economically meaningful, since the toner cartridges are costly constructed and consist of a lot of material. Accordingly, a refilled cartridge usually costs significantly less than a new cartridge. Since 2012 it is in Germany also possible to supply defective toner cartridges of material recycling. In previous years, about 80 % of the 55 million tons incurred cartridges were burnt in Germany alone, and a cartridge needed in the production on average 2 kg oil and causes about 6 kg CO2. The recycling of toner cartridges is usually uneconomical, so toner cartridges are subjected to recycling centers along with a bulky thermal disposal (incineration). A disposal of toner cartridges may not occur via domestic waste. Even empty cartridges contain residues of toner and therefore toxic, health and environmentally hazardous substances. This may not be disposed of with household waste. Improper disposal also excludes a recycle or even reuse.

Further meaning

Paper images or movies - - As a chemical toner or their solution for the treatment of developed silver photographs was called to modify the black tone by toning or recolor.