Over the years, two distinct forms of black have become available: one that blends readily with other colors for graphical printing, and a near-waterproof variant for text. Color inkjets use the CMYK color model: cyan, magenta, yellow, and the key, black.(In thermal printers) metallic plate / resistor: is heated with a weak electrical current which heats the ink.(In piezoelectric printers) piezoelectric substrate: houses the piezoelectric crystal.Common ink chamber: where ink is transferred from the body before printing.Cover plate: covers the nozzles when they are not in use.Nozzle plate: the part where ink goes through from ink cartridge to paper.Printheads of ink cartridges consists of four parts: Some ink cartridges have printheads installed on them. Others contain hydrophobic foam that prevents refilling. It also can make a smaller ink drop in some situations than thermal inkjet schemes. For example, roughly 1/1000 of every ink jet is vaporised due to the intense heat, and ink must be designed not the clog the printer with the products of thermal decomposition. This cool environment allows use of inks which react badly when heated. containing an ink channel, orifice, reservoir and crystal). The ink channels in a piezoelectric ink jet print head can be formed using a variety of techniques, but one common method is lamination of a stack of metal plates, each of which includes precision micro-fabricated features of various shapes (i.e. There are two types of crystals used: those that elongate when subjected to electricity or bi-morphs which bend. When current is applied, the crystal changes shape or size, increasing the pressure in the ink channel and thus forcing a droplet of ink from the nozzle. When the ink first begins to run low, the cartridge should be refilled or replaced, to avoid overheating damage to the print head.Īll Epson printers use a piezoelectric crystal in each nozzle instead of a heating element. The ink also acts as a coolant to protect the metal-plate heating elements − when the ink supply is depleted, and printing is attempted, the heating elements in thermal cartridges often burn out, permanently damaging the print head. Tap water contains contaminants that may clog the print head, so distilled water and a lint-free cloth is recommended. It must be administered carefully with a dropper or a syringe. But it is strong enough to dissolve clogs. Isopropyl alcohol does not damage the susceptible sponge that is vital in transferring ink to paper. Dried ink can be cleaned from a cartridge print head using 91% denatured isopropyl alcohol (not rubbing alcohol). The printing depends on the smooth flow of ink, which can be hindered if the ink begins to dry at the print head, as can happen when an ink level becomes low. This process takes a fraction of a millisecond. As a consequence, an ink droplet is forced out of the cartridge nozzle onto the paper. In response to a signal given by the printer, a tiny current flows through the metal or resistor making it warm, and the ink in contact with the heated resistor is vaporized into a tiny steam bubble inside the nozzle. Most consumer inkjet printers, such as those made by Canon, HP, and Lexmark (but not Epson) use a thermal inkjet inside each partition of the ink reservoir is a heating element with a tiny metal plate or resistor.