liquid toner The most well-known use of liquid toner is Electrolnk® by HP/lndigo. Here toner particles of 1 to 2 my are suspended in a liquid. The toner liquid is referred to as Isopar and adding special polarizing substances to the liquid toner electrically charges the toner particles.
By developing ElectroInk as liquid toner, Indigo is sticking to the offset printing method. The benefit of printing inks and liquid toners lies in their very small pigment/toner particle size, which enables much sharper image reproduction and can be transferred to printing substrate in very thin layers. When liquid toners are used with digital printing systems by Indigo, ElectroInk is in liquid form on the printing cylinder and is deposited at electronically generated points of the subsequent printed image via the principle of electrophoresis. The liquid toner is then transferred to the transfer cylinder in a liquid state. The heated surface of the rubber blanket cylinder (100 to 200ºC) plasticizes and fuses the polymer toner particles. The individual colours are transferred to the printing substrate in succession, building layer upon layer of toner on the paper.
For single-colour printing, only one rotation of the backing cylinder is required, whereas with four-colour printing the cylinder has to rotate four times before the sheet is completely printed and released. Transferring the heated ElectroInk to the printing substrate can also be referred to as laminating the toner layer, because no liquid toner is absorbed into the paper fibre. The dye substances in contact with the printing substrate dry instantly so no additional fixing of the toner is necessary. HP/Indigo’s liquid toner method calls for a specific surface quality for printing substrates.
