Impact printing is done by several tiny pins, aligned in a column, striking an ink ribbon positioned between the pins and the paper, creating dots on the paper. Characters are composed of patterns of these dots by moving the print head laterally across the page in very small increments.
The pins, contained in the print head, are driven by several hammers (actuating plate) which force each pin into contact with the ink ribbon (and paper) at a certain time. The force on these hammers comes from the magnetic pull of small wire coils (solenoids/drive coil) which are energized at a particular time, depending on the character to be printed. Timing of the signals sent to the solenoids is programmed into the printer for each character, and translated from information sent by the host about which characters to print.
Benefits: ? Price generally cheaper than other printing methods ? No special paper media. ? Highly reliable and durable in harsh hospitality environments such as kitchens. ? Impact receipts can be used with multi-part paper. This is ideal for credit card receipts and journaling.
Drawbacks: ? Noisy – fine for a kitchen but not an upscale boutique. ? Slower than other printing methods. ? Ribbons that need replacing – ink on your hands.