Basics of How an Inkjet Printer Functions

Inkjet printers are a staple in many homes, businesses and even schools and universities. They have a variety of uses from printing greeting cards to labels to business presentations and business cards. Inkjet printers once had a bad reputation for producing lower grade quality prints but technology has significantly advanced and many inkjet printers now provide clean, crisp prints at quick speeds.

Inkjet Mechanics Overview

In its most simple explanation, an inkjet printer works by spraying tiny dots of ink onto the paper in a specific order to create text or an image. In earlier machines it was easier to see the dots. Advancements in technology allow modern machines to spray ink dots that are small than the diameter of a human hair. The average diameter of a human hair is 70 microns and the dots of ink an inkjet printer sprays are between 50 and 60 microns in diameter.

The dots are sprayed in very specific pattern which creates the resolution or density. Resolution is measured in the amount of dot per inch. Different types of inkjet printers are able to print at different resolution. The higher the resolution, the better quality the print. Printers that print at higher resolutions also tend to be more expensive. An inkjet printer can print in resolutions of up to 1440 by 720 dots per inch (dpi). When creating a print of a photo, the dots have different colors to create a photo-quality print. You can enhance the quality of your photo print by choosing the right type of photo paper.

On the Inside

Few people take apart an inkjet printer unless they're trying to fix it. But if you were to take one apart, you'd see that there's a power supply, control circuitry, interface ports, a paper feed assembly with various parts and a print head assembly with various parts.

Modern inkjet printers have a standard power supply. Earlier models used an external transformer. The control circuitry is a tiny board with plenty of wires and knobs that control all mechanical aspects of the printer operation. In some ways it's like a computer circuit board and is also designed to decode information sent from the computer so that the content you need can be printed.

As far as interface ports are concerned, most printers are being manufactured with a Universe Serial Bus connector, also called a USB port. Often there's a parallel port that uses a wire to connect. You might still come across printers that use a serial port or computer system interface port to transfer information from a computer to the printer.

The paper feed assembly is, as the name implies, the mechanical parts that pull the paper through the printer. It starts with the paper tray or feeder. Inkjet printers are sheet fed and usually these sheets are stored in a tray until they're used. The tray is usually inside the printer. Some inkjets use a feeder which snaps onto the outside of the printer usually at an angle and usually at the back of the unit. Feeders tend to hold fewer sheets of paper.

Rollers grip and advance the paper towards the print head where the ink is sprayed on the surface of the paper in a very specific pattern. A paper feed stepper motor controls the speed at which the rollers pull the paper making sure the paper moves at the exact increments to create the printed image.

The printer head assembly is the section of the printer that distributes the ink. They include the print head, cartridges, print head stepper motor, belt and stabilizer bar.

The print head is the part of the printer with the nozzles that spray the ink. The cartridges hold the ink. The print head stepper motor moves the print head back and forth over the paper and is attached to the head with the belt. The stabilizer bar basically reinforces the entire print assembly unit to reduce the chance of unnecessary movement which could ruin the print.