Non – Impact Printers:Ink Jet Printers

1. Ink Jet Printers:

Combining the easy of use like impact printers with the graphics capabilities of offset printing has made the ink jet printer the most common printer found in home and business today. These printers are also called bubble jet printer and are the least expensive than the laser printer. Ink jet printers produce images by spraying ink through tiny nozzles in a print head that passes over the page at the rate of approximately 250 characters per second. The ink is absorbed into the paper and dries instantly. Various colors of ink can also be used. It produces the output similar to dot matrix printers by laying small dots of ink on the output media. The difference is that ink jet printers do not use pins to impact the paper. Instead ink is fired directly from the printhead in small droplets which are absorbed and held in place by media substrate. Thus ink jet printers are known as non-impact printers.

Operation of Ink Jet Printers
To understand an ink jet printer works you must understand its most important mechanical component, the printhead. The inkjet printhaead acts much the way a dot-matrix printhead does, in that it passes back and forth across the paper and place small dots of the ink on the paper. What makes the ink jet printhead unique is that does this without actually touching the paper.
The process is very simple. Ink is stored in a reservoir which is connected to the printhead. These reservoirs can be permanently joined to the printhead or they can be independently replaceable components. Form the reservoir ink flows through a filter into an area called pre-chamber, which acts as a temporary storage area. From the pre-chamber the ink flows into the firing charmer. The firing chamber looks like a small flattened box. The bottom of the firing chamber has a series of holes in the nozzles. Directly above each nozzles, one or more firing nodes (they can be terminal resistors or piezo crystal) provide the impulse which moves the ink through the nozzles. The surface tension of the ink keeps the ink from escaping the nozzles normally, but where a firing node is activated the ink expands, and moves through the nozzles and falls towards the paper. By controlling many variables such as firing temperature, length of firing time, surface tension of the ink, and the diameter of the nozzles opening, the proper sized droplet of ink can be realized.