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Inkjet Printer Inside: Image Gallery Inkjet printers spray minuscule ink droplets onto paper, forming a smooth and continuous line. Check out more pictures of inkjet printers.
Mytour.comWherever you are reading this, it's highly probable you have a printer close by, and it’s likely an inkjet printer. Since their debut in the mid-1980s, inkjet printers have become more efficient, powerful, and affordable.
An inkjet printer is any type of printer that deposits extremely tiny ink droplets onto paper to form an image. If you ever examine a page printed by an inkjet, you will notice that:
- The droplets are incredibly small (typically between 50 and 60 microns wide), smaller than a human hair (70 microns)!
- The droplets are arranged with high accuracy, achieving resolutions of up to 1440x720 dots per inch (dpi).
- The droplets come in various colors, blending together to produce photo-quality pictures.
In this article, you'll discover the different components of an inkjet printer and how they work together to produce an image. You'll also learn about the ink cartridges and the specialized paper used by some inkjet printers.
To start, let's briefly explore the various printer technologies available.
Impact vs. Non-impact
A Hewlett Packard LaserJet 4050T
Mytour.comThere are a number of prominent printer technologies on the market. These technologies can be divided into two primary categories, with several different types within each category.
Impact - These printers use a mechanism that physically makes contact with the paper to produce an image. There are two main types of impact technologies:
- Dot matrix printers work by using small pins that strike an ink-coated ribbon, transferring the ink to the paper at the point of impact.
- Character printers function like computerized typewriters. They feature a ball or series of bars that have embossed characters (letters and numbers). The selected character strikes the ink ribbon, transferring the image onto the paper. These printers are fast and accurate for basic text but are limited in their use beyond that.
Non-impact - These printers do not make contact with the paper when producing an image. Inkjet printers belong to this category, which also includes:
- Inkjet printers, as explained in this article, use a series of nozzles to directly spray ink droplets onto the paper.
- Laser printers, discussed in detail in How Laser Printers Work, employ dry ink (toner), static electricity, and heat to transfer and bond the ink to the paper.
- Solid ink printers use wax-like ink sticks that are melted and applied to the paper, where they then harden in place.
- Dye-sublimation printers use a long roll of transparent film made of sheets in red, blue, yellow, and gray, which are bonded together. This film contains solid dyes in the four basic printing colors: cyan, magenta, yellow, and black (CMYK). The print head adjusts its temperature based on the required color, causing the dyes to vaporize and permeate the glossy paper surface before solidifying. The printer performs a complete pass over the paper for each color, slowly building up the image.
- Thermal wax printers combine dye-sublimation and solid ink technologies. They use a ribbon with alternating CMYK color bands that passes in front of a heated print head. Tiny heated pins melt the wax, which adheres to the paper and hardens in place.
- Thermal autochrome printers place the color in the paper rather than in the printer itself. The paper has three layers (cyan, magenta, and yellow), with each activated by a specific amount of heat. The print head, equipped with a variable heating element, passes over the paper three times, applying the appropriate temperature to each color layer as needed.
Among all the amazing printing technologies, inkjet printers stand out as the most popular. In fact, the only real competition today comes from laser printers.
Now, let’s dive deeper and explore the components inside an inkjet printer.
Exploring the Inside of an Inkjet Printer
The print head assemblyTypical inkjet printers consist of several key components, including the Print head assembly:
- Print head - The central component of an inkjet printer, the print head features a series of nozzles responsible for spraying tiny ink droplets onto the paper.
- Ink cartridges - Ink cartridges vary by printer model and manufacturer. They can come as separate black and color cartridges, as combined black and color cartridges, or even individual cartridges for each ink color. In some models, the print head is integrated into the cartridge itself.
- Print head stepper motor - This stepper motor drives the print head assembly (which includes both the print head and ink cartridges) back and forth over the paper. Some printers feature an additional motor to park the print head assembly when the printer is idle. This parking function acts like a brake, preventing unintended movement of the print head assembly.
- Belt - A belt connects the print head assembly to the stepper motor, facilitating precise movement.
- Stabilizer bar - The stabilizer bar ensures that the print head assembly moves with accuracy and control.
Paper feed assembly:
- Paper tray/feeder - Most inkjet printers feature a paper tray for loading paper. Some printers use a feeder instead, which typically opens at an angle from the back of the printer. The feeder generally holds less paper than a traditional tray.
- Rollers - A set of rollers grabs the paper from the tray or feeder and moves it forward to ensure the print head assembly is positioned for the next pass.
- Paper feed stepper motor - This motor drives the rollers that move the paper, ensuring it advances in precise increments for continuous image printing.
- Power supply - Unlike older printers that often used external transformers, modern printers typically feature an integrated power supply built directly into the printer.
- Control circuitry - A compact yet advanced set of circuits is embedded in the printer, managing the mechanical operations and interpreting data sent from the computer.
- Interface port(s) - While the parallel port is still in use by many printers, newer models predominantly rely on the USB port. Some printers may also utilize a serial port or a small computer system interface (SCSI) port.
Heat vs. Vibration
View of the nozzles on a thermal bubble inkjet print headInkjet printers generate ink droplets in a variety of ways. Currently, two major inkjet technologies are used by manufacturers:
- Thermal bubble - This technology, used by brands like Canon and Hewlett Packard, is commonly known as bubble jet. In a thermal inkjet printer, small resistors heat the ink, causing it to vaporize and form a bubble. As the bubble expands, it pushes ink through the nozzle and onto the paper. When the bubble bursts, it creates a vacuum that draws more ink from the cartridge into the print head. A bubble jet print head typically has 300 or 600 tiny nozzles, all of which can fire ink droplets at the same time. Click the button to see how a thermal bubble inkjet printer works.
- Piezoelectric - Invented by Epson, this method uses piezo crystals. A crystal is placed at the back of the ink reservoir in each nozzle. When the crystal receives a small electric charge, it vibrates, pushing a small amount of ink out of the nozzle. As it vibrates outward, it draws in fresh ink to refill the reservoir.
Let’s go through the printing process to better understand what actually happens when a document is printed.
Click "OK" to Print
When you press the print button, a series of events are triggered to begin the printing process.
- The software you're using sends the print data to the printer's driver.
- The driver then translates this data into a format the printer can understand and verifies that the printer is online and ready to print.
- Next, the driver sends the data from the computer to the printer through the connection interface (such as parallel, USB, etc.).
- The printer receives the data and temporarily stores it in a buffer. The buffer's size varies from 512 KB to 16 MB of RAM, depending on the model. This buffering allows the printer to process data quickly, so you don’t need to wait for the entire page to finish printing. A larger buffer can hold more complex or multiple documents.
- If the printer has been idle for a while, it will usually perform a quick cleaning cycle to ensure the print head(s) are clear. After the cleaning is done, the printer is ready to start printing.
- The control circuitry triggers the paper feed stepper motor, which moves the rollers to load a sheet of paper into the printer from the tray. A small trigger in the tray is activated when there’s paper. If it’s not pressed, the printer will show an “Out of Paper” LED and alert the computer.
- Once the paper is correctly positioned, the print head stepper motor uses a belt to move the print head assembly across the page. The motor pauses briefly at each point where ink is sprayed onto the paper, then advances slightly before stopping again. This happens so rapidly it seems like continuous movement.
- Multiple ink droplets are applied at each stop, spraying CMYK colors in specific amounts to create any other color you need.
- At the end of each pass, the paper feed stepper motor moves the paper slightly forward. Depending on the printer, the print head either resets to the start of the page or reverses direction to continue printing.
- The printing continues until the entire page is finished. Printing time can vary based on the complexity of the page, image size, and printer model. For example, a printer may print 16 pages per minute of black text but take a couple of minutes to print a full-color, image-heavy page.
- When printing is done, the print head parks. The paper feed stepper motor moves the rollers to push the printed page into the output tray. Since most modern inks dry quickly, you can pick up the page right away without smudging.
In the next section, we’ll explore the ink cartridges and paper used in the printing process.
Paper and Ink
A typical color ink cartridge: This cartridge contains separate reservoirs for cyan, magenta, and yellow ink.
Mytour.comInkjet printers are generally affordable. They cost less than most black-and-white laser printers, and significantly less than color laser printers. In fact, several manufacturers even sell some printers at a loss. It’s not uncommon to find a printer on sale for less than the price of the ink cartridges required for it!
Why do they do this? The answer is simple: they rely on the supplies you buy to generate their profit. This is similar to the model in the video game industry. The hardware is often sold at or below its actual cost, but once you've purchased a specific brand, you're locked into buying their compatible products. For instance, you can't buy a printer from Manufacturer A and ink cartridges from Manufacturer B—they just won’t work together.
Another strategy they use to cut costs is by integrating the print head into the ink cartridge itself. Manufacturers argue that since the print head is the most likely component to wear out, replacing it every time you change the cartridge helps prolong the life of the printer.
The type of paper you use in your inkjet printer plays a major role in determining the quality of the printout. While regular copier paper can be used, it doesn’t provide as sharp or vibrant an image as paper specifically designed for inkjet printers. There are two key factors that influence image quality:
- Brightness
- Absorption
The brightness of paper is typically determined by its surface texture. Rougher paper scatters light in multiple directions, while smoother paper reflects light more directly, making it appear brighter. This, in turn, makes the printed image appear more vibrant. A good comparison can be made by looking at a photo in a newspaper versus one in a magazine. The smoother, glossier paper in magazines reflects light much more effectively than the rougher texture of newspaper paper. Paper labeled as bright is usually smoother than average.
Another crucial factor affecting image quality is absorption. When ink is deposited on the paper, it should remain as a precise, symmetrical dot. Excessive absorption into the paper can cause the ink to feather, which means the dot will expand unevenly and cover a slightly larger area than intended. This leads to a blurry image, especially along the edges of text and objects.
Imagine the dot on the left as being on coated paper, and the dot on the right as being on low-quality copier paper. You'll notice how irregular and larger the dot on the right is compared to the one on the left.Feathering, as mentioned, occurs due to the paper’s absorption of the ink. To prevent this, high-quality inkjet paper is often coated with a waxy layer that helps keep the ink on the surface. Coated paper usually produces a much sharper print. The lower absorption of coated paper is essential for achieving high resolution with many modern inkjet printers. For example, an Epson inkjet printer can print at up to 720x720 dpi on regular paper. However, with coated paper, this resolution can increase to 1440x720 dpi. This happens because the printer can slightly shift the paper and print a second row of dots for every normal row, ensuring the ink doesn’t feather and cause a blur.
Inkjet printers are versatile and can print on a wide range of media. Commercial inkjet printers may even print directly onto objects, like the label on a beer bottle. For personal use, there are various specialty papers available, including adhesive-backed labels, stickers, business cards, and brochures. You can even find iron-on transfers that allow you to print designs and transfer them onto T-shirts! Inkjet printers are an excellent and affordable way to bring your creative ideas to life.
For further details on inkjet printers and related topics, be sure to check out the links below.
Due to the high cost of inkjet cartridges, a thriving industry has developed around the concept of refilling them. For many, refilling is a cost-effective option, but there are a few important things to keep in mind:
- Ensure that the refill kit is compatible with your printer model. As discussed earlier, different printers employ various methods for transferring ink to paper. Using the wrong ink can affect print quality or even damage your printer. While some commercial inkjets use oil-based inks, most home and office inkjets rely on water-based ink. The ink composition can differ significantly between brands. For instance, thermal bubble inkjets require ink that remains stable at higher temperatures than piezoelectric printers.
- Many manufacturers insist that only their approved ink be used, and using third-party refills could void your warranty.
- While refilling cartridges is possible, you should be cautious with those that integrate the print head. It's not recommended to refill these cartridges more than two or three times, as doing so may cause the print head to degrade and potentially damage your printer.
Visit this site for helpful links and information on inkjet refills.
