| Printheads are the complex nozzles behind jetting or spraying ink from the cartridge to the desired media (paper, cloth, cd, etc.). There are two main types of printheads, including printheads that employ a continuous inkjet and printheads that utilize drop-on-demand printing. The printheads that use the continuous inkjet method, also known as Piezo or Micro-Piezo printing, have multiple chambers that are constantly filling with ink and being squeezed or pumped out. Each tiny chamber contains a piezo element which changes shape, by contracting the instant an electrical current touches it. Each contraction creates an acoustic wave successfully breaking the ink into smaller droplets before an electrostatic deflection plate repels the newly charged ink droplets onto the media or back into a recycling chamber. Some Piezo elements are paired with vibration plates which allow the piezo crystal to rapidly expand and retract inside the chambers, pumping the ink through the microscopic nozzles. The printheads using the drop-on-demand method or bubblejet printing contain a series of chambers that each have their own heater. The heat causes the water-based ink to quickly vaporize into another chamber forming a bubble and pushing the ink that was already occupying this new chamber, out through the microscopic nozzles. The bubble will then burst and collect into this new chamber before another bubble of heated ink pushes it out through the nozzles. Inkgrabber.com offers the Original Equipment Manufacturer (OEM) or Genuine Printheads which are created by the printer manufacturer. All products, including the HP OEMC4921A, are ISO 9001 certified, meeting the highest standards and offered at only $36.99. Every Genuine HP Printhead has up to a 2-3 Year shelf-life and is backed with the Inkgrabber 90 Day Money Back Guarantee. In addition Inkgrabber.com also provides a 1 year exchange policy for damaged or faulty hardware. |
HP C4921A 
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The OEMC4921A is compatible with the printers listed below:
