Posts Tagged 'inks'

Inside the Ink Cartridge

Most of us use printers in our everyday lives, whether it’s at work, home, or even in libraries and schools. Printers have long been a part of our culture, revolutionizing how we received news, how advertisers were able to relay messages, how stories and lessons were able to be recorded on a wide scale, and much more. The first printers were complex machines with a numerous variety of components and attachments and needed constant monitoring. Now, we see a printer and immediately know how to operate them, how to change the ink cartridges, and how to give them a proper supply of power. In general, these machines and their accompanying cartridges are pretty familiar and very simple to use, although we seldom look at what is really happening inside the ink cartridge during the printing process.

 The ink cartridge, although it looks uncomplicated and easily slides in and out of the printer when replacing the ink, is actually an intricate component with several moving, conducting, charging, and supporting pieces that make up a single ink cartridge.

The main components of every cartridge are the sump or receptacle portion which expels the ink and the peripheral walls, encasing the cartridge and giving the object its recognizable, rectangular shape (in most cases, although each manufacturer varies). These also happen to be the biggest and most prevalent pieces as they hold and protect the ink from spilling inside the printer.  The sump is also responsible for responding to and supporting the print heads, which act as a funnel to jet ink through to the media. The sump and the walls together, also make up a reservoir for the ink to rest in.

On the diametrically opposed side of the sump portion, designers usually include a small handle with a knurled surface to facilitate the insertion and removal of the ink cartridge. This basically means the cartridge has a protruding handle at the top and in the back of the unit for users to more easily handle the cartridge.  Along with an added handle, the outer portion also contains stabilizing protrusions or datum features at the bottom of the cartridge (much like a stand or feet) to accurately align the cartridge in the printer.

 At the bottom of the unit, a small hole known as the charging opening is also created into the frame or wall which grants access to the ink reservoir. This is where the ink is initially filled when being put together by the assembling machine.

In between the sump portion and the framing walls of the cartridge lies a recessed region which bisects the cartridge. These recessed regions taper off to angled edges known as the chamfers. The chamfers main purpose is to correctly position media when the media is passing by the sump portion of the cartridge. The sump is actually two laterally spaced plates, each with smooth metal faces and ribbed groves on the inner section of the plates to ensure the print head is adhesively secured (or connected) to the cartridge.

A flexible circuit board or flexible member is then added to the cartridge, situated on the sump portion and part of the peripheral wall portion. The circuit board is a crucial piece to the cartridge supporting electrical traces that provide power to an actuating mechanism and delivering electrical impulses to the necessary components inside the cartridge. An electrical impulse will be regulated then distributed to “pogo” pins, a piezo crystal, or an electrical resistance heating material (such as thermal inks) to expel the droplets out of the chamber and through the print head nozzles.

To supply power to the flexible circuit board, a series of “pogo” pins in the ink trough of a printer will touch the conductor strips on the circuit board of the cartridge, creating a pathway for electricity to travel through. Sometimes chips are also added onto cartridges to count the number of pages printed with a particular cartridge and to help big corporations and brand name manufacturers regulate and ultimately monopolize the ink markets.

These are generally the main pieces involved when comprising an ink cartridge, although each manufacturer and each printer series has their own versions, additions, and arrangements of ink cartridge compositions.  

Photo Ink vs. Regular Ink

There are several types of inks and ink formulations when it comes to printing, but they all have the same general purpose; to deliver an image onto a piece of media passing through the printer. However, some ink cartridges will deliver superior results when printing text and others will yield better results when producing images and photographs. The differing results are caused by the variation of elements found in the ink mixtures. An ink cartridge contains a basic mixture of water, glycol (a carrying liquid), and dyes or pigments and are intended to be jetted or sprayed onto paper or media, eventually creating an image.

Differences

The main difference between photo inkjets and regular inkjets is the ability of photo ink formulations to provide lighter tones of each color, commonly being cyan, magenta, and black. A regular cartridge will dispense wider set ink droplets to give image colors a lighter look. However, this makes lighter colored printouts look grainy and even multi-colored when inspected closely. This is because regular ink mixtures can only dispatch color so lightly, being intended for brighter execution to give printouts more vibrancy.

Photograph inks, on the other hand, will produce much lighter tones, perfect for shading and coloring elements such as faces and skin tones that have light colors. Since these mixtures produce lighter color, the ink is not as widely dispersed and results in smoother printouts that can capture high levels of detail. Many photograph ink compositions also avoid pigmented colorants since they do not sit as well on coated media such as photo glossy paper.  Ink formulations vary greatly depending on the machine being used, the frequency of ink being ejected, and depending on the type of printing the machine is intended for.

Ink Types

There are three basic ink compositions, that mostly all inks can be categorized into including Dye-Based Inks, Pigment-Based Inks, and Hybrid Inks. Dye-Based inks are composed of colorants dissolved in a liquid, such as water or glycol and have the most vivid and rich finishing results. Dye-Based inks also have a wide color gamut, providing colors unreachable by other mixtures and are compatible with a wide range of photograph papers. Unfortunately these ink mixtures do not last long and fade easily with light and become runny when moisture is added. In general, a dye-based ink formulation printout will last between 5 and 25 years depending on the surrounding environment.

Pigment-Based inks on the other hand, contain insoluble powder pigments that are suspended in the ink composition and do not dissolve into the solution like dye-based inks. These pigments are coated in a resin-like mixture making them much more stable and giving them resistances to fading or light. A pigment-based printout can last anywhere from 75 years to 150 years depending on how and where the printout was stored and displayed.  However, pigment-based inks do not soak into media as readily and have a tougher time adhering to coated paper.

Hybrid inks are a mixture of dye-based inks and pigment-based inks, and are sometimes referred to as pigmented inks. Combining the longevity of pigment-based inks with vibrancy of dye-based inks, Hybrid inks can be used for a number of applications and often offer superior printing results. Hybrid inks are known as pigmented inks since they use dye-based colorants and pigmented particles together, modifying the benefits and weaknesses of each type. Pigmented inks will have a wider color gamut than pigment-based inks but will not last as long. Pigmented inks (or Hybrid inks) can last up to 75 years when kept in an archival environment, such as being behind glass in a picture frame.

Similarities

Most inkjet printers and ink cartridges also contain conductive elements to help shepherd or guide the ink to the page, usually reducing the size of the droplet in the process, for higher resolution printouts with sharper definition. Both photo and regular ink cartridges can be found with these assisting elements. The most common element that helps to shape and delivery ink is the Piezoelectric crystals. When a small electrical current passes through a Piezo crystal, the element will rapidly change shape forcing the ink out of the printer nozzles. The reaction shapes and can reduce the ink droplet size while forcing the mixture out of the cartridge and onto the paper.

Ink cartridges have differing elements depending on the type of printout being created, which will enhance a project and the overall quality when using the right selection of inks. For example, when printing text documents, a matte black ink cartridge formulation such as the Epson T054820, will yield the best results since the ink has a softer look, making the text easier to read for long periods of time. Using a photo black ink cartridge on text document printing will result in overly shiny characters or grayish texts that do not read as well. 


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