Understanding Impact Printers – CompTIA A+ 220-901 – 1.14

Dot-matrix printers are some of the most venerable printing methods in used today. In this video, you’ll learn how dot-matrix printers combine a print head with a fabric ribbon to create our printed output.

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One of the most common kind of impact printers is a dot-matrix printer. It’s called an impact printer because we are literally taking a tiny pin inside of the print head, pushing it through a ribbon, and hitting a piece of paper to put a mark on that paper. If you look very closely, you can even see the tiny little pin marks that are being made as it’s pushing through the ribbon and hitting the paper to make the mark.

This is a great printer to use for making multiple copies because you’re able to push through a carbon, or a carbon-less set of papers, all at one time with that single pin and have multiple copies instantly available. It’s also a very low cost per page. Your ink is from the ink cartridge, and it’s very low cost relative to other types of printers.

Unfortunately, because it is physically impacting this piece of paper, it’s relatively noisy. So it’s not good to use in environments where you might disturb others. Also, the graphic capabilities of this are very poor compared to other kinds of printers. This is really designed for printing text on a piece of paper. Interestingly enough, you’ll find impact printers being used in very niche environments, like car rentals, or airports, where every time you’re on a plane and every time you’re renting a car, they print out a lot of information directly from a dot-matrix printer.

A dot-matrix printer has a printer head that is pushing through this ribbon and onto the piece of paper. And it’s only a single print head, so it has to move all the way across this piece of paper to be able to mark and put the information onto the page.

Here’s a close up of the print head. You can see the ribbon placed in between the print head and the piece of paper itself. And it’s going back and forth over this particular piece of paper to be able to hit every spot it needs to make that impression. You look at the other side of the print head, it looks like this. This is a 24 pin print head, with 12 pins on each side. That’s what’s moving across the paper and making those small marks. And that matrix is building those different characters that we see on the page.

The ink that we see in a dot-matrix printer comes directly from this printer ribbon. This is a fabric ribbon. It’s one long piece of ribbon that goes into the cartridge itself. It’s bundled up and then finally comes back out as one long circle. When we start running out of ink, you’ll start seeing the printout on a dot-matrix printer get lighter and lighter. So you have to replace this cartridge. That’s relatively easy to replace. You just pull out the old one and put a new one in its place. But it is a proprietary size, so you have to have exactly the right kind of printer ribbon cartridge for the dot-matrix printer that you own.

Because this is one long ribbon, if you looked inside of the printer cartridge, you would see it bundled up like this inside of the cartridge, and it just keeps cycling through until we’re able to get rid of all of the ink that’s across every bit of this ribbon.

The paper that comes from a dot-matrix printer can be pulled through with a friction feed, which uses just standard paper, but could also use this tractor feed, where you have small holes on each side of the paper and it’s pulling them through using those holes. This gives you a continuous piece of paper that’s constantly moving through the printer, and it just has perforations that you can use between the pages to separate those pages.

The holes in the tractor fed paper have to line up perfectly, especially if you’re printing to a form, or you have to print on a very specific part of the paper. And very often the paper will be set up so that will be one long continuous piece. And occasionally the paper may be even perforated on the side, so you can remove the holes once you’ve printed your output.