Dot Matrix Printer

The Jurassic era of printers consisted of a specie known as impact printer whose members trod the lengths and breadths of this blue planet with their heads held high above the horizon! The two major races of this specie were the daisy wheel - the elder one - and the dot matrix – the younger one - printers. Time, the impartial witness, will confirm that out of the two raptors the younger brethren populated the dense rainforests of the computing world until the meteors – the inkjet and the laser printer – struck the earth to efface their blue-blood line altogether!

Working principle of device:

Dot matrix printers can neither rival the quality or speed of inkjet or laser printers and are costly to maintain. In addition to that these printers exacerbate the ambient noise levels to insufferable limits! Hence dot matrix printers are rarely used today. The printer consists of a print head that contains numerous pins, a cloth ribbon soaked in ink, a stepper motor to move the print head and entry and exit rollers to move the paper through the printer. These printers can print virtually all kinds of graphics and fonts as they do not rely upon the striking of the pre-carved characters on the paper as was the case with type writers and daisy wheel printers (on a nostalgic note: characters were engraved on a wheel whose shape resembled that of a daisy flower and hence the name). The print head can abound up to 48 pins. However, 24 pin heads were fairly common in those days. The print drivers convert the digital data into signals that the printer can understand. The instructions are passed to the printer character after character unlike laser printers that take instructions of how to print the whole page at a single go. All of the pins in the print head get excited in a certain order, as suggested by the instruction received from the driver, and ‘hit’ the cloth ribbon that is soaked in ink. This ‘impact’ caused the ink to get transferred to the paper where a dot appears for every pin that struck the ribbon. The various combinations/patterns of the pins striking the ribbon create a plethora of graphics and fonts. Thus the overall print consists of innumerable dots crunched together in a definite manner to create an illusion of a fluid image. The quality of the print is often draft quality or NLQ (near letter quality) which largely depends upon the number of pins present in the print head (it ranges from 9 to 24 in normal cases and means that each character consists of 9-24 dots). The stepper motors move the print head across the paper from the left to the right and back. The entry and exit rollers account for the vertical motion of the paper inside the printer.

Device installation: The printers can be connected via the Parallel, Serial, USB or the Ethernet ports. Appropriate drivers for the operating system used must be installed before the printer is ready to hum happily along the good road!

Manufacturer of device, its models and prices:

1.      Epson – Epson FX-2175 DOT Matrix Printer 9-Pin (Rs. 14,500), Epson Dot Matrix LQ50 Monochrome (Rs. 9,498), New Epson LX-310+II 9-Pin USB DOT MATRIX (Rs. 8,950) etc

2.      TVS – TVS Classic Dot Matrix Printer MSP 240 (Rs. 8,268), TVS MSP-245 Monochrome (Rs. 11,890), Tvs MSP 250 Monochrome (Rs. 10,088) etc

Standard Configuration of device: As a special note, these printers require a special kind of feed paper that is thin, continuous and has a column of holes punched on both the sides of the paper. Owing to these characteristics the feed mechanism used is called the tractor-feed mechanism where two protruding wheels insert themselves into the holes on the paper while a line is being printed and then get detached only to be re-attached to the next holes in the series! Much Ado about nothing ain’t it?! However, modern laser printers use friction mechanism instead of tractor feed and are thus capable of printing even on ordinary papers. The speed of the printer is measured in cps (characters per second) and range from 50 to 1500 cps! Even at a whooping 1500cps the printers max out at 800 pages per hour which doesn’t even touch the hem of the throughput of high-end laser printers roaming in the wild today! 

Cost: Dot matrix printers are cheap and require little maintenance. The ribbon, ink, feed paper and other replaceable components needed for its operation are relatively cheap. It is safe inasmuch as to say that a one-time investment of about Rs. 10,000 – Rs. 15,000 will suffice so long as the printer breathes!

Market share of different models (Standard companies only):

l  Epson

l  TVS