LED printing is a recent technology in computer printing. LED printers are capable of printing at the same quality as most laser printers. LED printers were developed by Casio. These printers work much like laser printers but utilize a LED panel that recreates the image on a negatively charged drum.
The technology used in LED printing gives the same results as conventional laser printing. It uses the same method of applying toner to the paper. It uses a light-emitting diode array as a light source in the printhead. A static charge is applied to the photo-receptive drum. The light from the LED array hits the drum and the charge is reversed and creates a pattern of dots that corresponds to the image that finally appear on the page. Then electrically charged dry toner is applied, which sticks to the areas of the drum that have had their charge reversed. Finally it is applied to the paper as it passes past the drum on its way to the output tray.
There are technical limitations that lowers the quality of LED printers against the highest quality laser printers. LED printers function by means of an array of LEDs built into the cover of the printer. A LED printer having a resolution of 300 dots-per-inch must have 300 LEDs per inch, while a printer with 600 dpi resolution must have 600 LEDs per inch. A number of laser printers commonly prints at 1200 dpi. But making that much small LEDs is quite difficult. LED printers print a skewed image resolution such as 600x1200 dpi. Their horizontal resolution is limited to 600 dpi by the physical size of the LEDs. However the vertical resolution is simply a matter of how fast the LEDs flash as the paper passes by.
Advantages of LED Printers
LED printers are mechanically more efficient than conventional laser printers, since they have fewer moving parts.
Depending on the design, LED printers can have faster printing rate than some laser-based designs.
A row of LEDs is cheaper to make than a laser and mirror with lots of moving parts. Hence they are generally cheaper to manufacture.
The LED systems are also compact in comparison to conventional laser printers.
Disadvantages of LED Printers
The horizontal resolution of LED printers is absolutely fixed and that is the main disadvantage of LED technology. Though some resolution enhancements can be applied but they are not sufficient to compete with the true lasers.
The efficiency and speed of LED printers come to its best when continuous, high-volume printing is required.