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)Ink is all around us — in the pens we use, on the newspapers and magazines we read, decorating the billboards we view, on the signs and banners we see, and of course, in our inkjet printers. Most of us take it for granted. Except for the occasion when the ink in a pen or cartridge goes dry, as typical consumers, we don’t think much about ink — we just expect it to be there when we need it.
But for an inkjet remanufacturer, ink is the fuel that runs the engine. And just as putting regular gasoline in a diesel automobile can cause engine damage and affect performance, putting the wrong ink in an inkjet cartridge can have the same unfortunate results. Understanding some basics about ink can help in making choices that will enhance the performance of remanufactured cartridges and lead to greater customer satisfaction and profitability.
So What Exactly Is Ink Anyway?
Ink is a chemical composition used to create an output. However, all inks are not alike. There are many different types of ink for many different uses, and they are not interchangeable. Inkjet ink is one category of ink, and within it there are sub-categories of inkjet applications:
* Desktop: Text, charts, graphics.
* Photographic: Photo creation, reproduction, restoration.
* Wide format: Signs, banners, billboards, POS, fine art reproduction.
* Industrial: Bar codes, mailing, labels.
* Specialty: Dye sublimation, OCR, security, medical imaging.
Inks for desktop applications are the lifeblood of inkjet remanufacturing and will be the focus of this article.
A Recipe for Ink
Desktop inkjet inks are aqueous (water-based). Because of this, a remanufacturer working with water-based ink can set up shop without a large capital outlay for special venting and hazardous material precautions, unlike some businesses that use solvent-based inks for industrial and specialty applications.
Desktop inks are composed of seven to 14 different chemicals. See Figure 1.
Ink quality is determined by measuring the following physical properties. These are important for the remanufacturer to consider when researching and selecting inks.
Figure 1.
Viscosity — measurement of the flow properties of ink. This impacts laydown, spread, dry time, drop size and flow.
Surface tension — the ability of a liquid to wet a surface. This is one of the most important parameters. It affects ink flow through the sponge or bladder, drop integrity, edge acuity, print sharpness and inter-color bleed.
pH — Measure of acidity of a water-based solution. It normally should be above neutral (7.0) and in the slightly basic range. Incorrect pH can cause color shifts on certain media; it may also cause damage to the cartridge or printer components.
Conductivity — Measurement of inorganic salts in the ink. In general, the value of this measurement is related more to dye purity than to any performance factor.
Color absorbance — Measurement of color shade and intensity. This affects tonal reproduction, halftones, gray tones and shade gradations.
Visual color — A colorimeter is used for quantitative analysis of color. Media, lighting and laydown can all affect the visual color of a printed sample.
Ink purity — Measurement of dissolved solids in the ink. Impurities can cause nozzle clogging and major print failure.
Dye-Based Versus Pigment-Based
Inks for inkjet cartridges are further broken down into dye-based and pigment-based. There are advantages and disadvantages to each.
Dye-based inks are made by completely dissolving liquid or powdered dye in purified water. They offer a wider variety of color selections and are easier and cheaper to make than pigment-based inks. However, dye-based inks have a tendency to soak into the paper fibers and spread out more, which can lead to problems with wicking and bleeding, as well as quicker fading.
Pigment-based inks are formed by suspending sub-micron particles in solution (called dispersion). These minute crystals reflect light and adhere to the printing medium. The pigment sits on the paper surface more readily than a dye. As a result, pigment-based inks are more lightfast and colorfast, making them preferable for archival purposes. However, the dispersion in pigment-based inks can make them more prone to nozzle clogging than dye-based inks.
The chart in Figure 2 compares different characteristics of pigment- and dye-based inks.
Figure 2.
Currently, most pigment-based inks are black, and most colored inks are dye-based, although the industry is starting to evolve towards the use of pigmented colored inks.
When remanufacturing inkjet cartridges, it is important to know which cartridges require dye-based ink and which require pigmented. It’s common for some OEM ink to remain in a cartridge to be remanufactured, even after it has been vacuum cleaned. If pigmented ink is put in a dye-based cartridge (or vice versa), the new ink could interact with the remaining old ink, causing a change in the chemical makeup. This in turn can increase the risk of cartridge failure.
There are some specialty inks available that are formulated to be used successfully in either environment. An ink supplier will be able to provide more information.
Figure 3 provides a list of some common cartridges, categorized as dye-based or pigment-based.
Figure 3.
Testing the Ink
Preferably, inks should be tested thoroughly before being used in production. To get the most out of the testing process, request a sample from the manufacturer and:
* Print comparison pages with both the test ink and OEM, using the same printer and exactly the same paper type.
* Judge them as a customer would.
* Test for blackness, crispness, dry time, color bleed and color hues.
* Print on different media and different weights of paper.
* Compare total page count (how many pages a remanufactured cartridge puts out versus the OEM).
* Let the cartridge with test ink sit for several months and then re-test.
Ink Storage
Most ink has a shelf life of approximately one year. Ideally, it should be stored at room temperature (around 72 degrees Fahrenheit/22 degrees Celsius). Extremes of heat, cold or humidity could cause changes in the ink’s chemical composition over time.
It is also important to cover any opened ink supply to protect it from contaminants. One way to accomplish this is to run the ink supply line through a hole drilled in the original cap and then screw the cap back on. See Figure 4.
Figure 4.
In Summary
As we have seen, ink chemistry and formulations can determine, at least in part, the final quality of a printed image. That makes ink selection a critical step in the remanufacturing process. Understanding ink’s basic properties, characteristics and testing mechanisms gives the remanufacturer an edge in making that decision.
But for an inkjet remanufacturer, ink is the fuel that runs the engine. And just as putting regular gasoline in a diesel automobile can cause engine damage and affect performance, putting the wrong ink in an inkjet cartridge can have the same unfortunate results. Understanding some basics about ink can help in making choices that will enhance the performance of remanufactured cartridges and lead to greater customer satisfaction and profitability.
So What Exactly Is Ink Anyway?
Ink is a chemical composition used to create an output. However, all inks are not alike. There are many different types of ink for many different uses, and they are not interchangeable. Inkjet ink is one category of ink, and within it there are sub-categories of inkjet applications:
* Desktop: Text, charts, graphics.
* Photographic: Photo creation, reproduction, restoration.
* Wide format: Signs, banners, billboards, POS, fine art reproduction.
* Industrial: Bar codes, mailing, labels.
* Specialty: Dye sublimation, OCR, security, medical imaging.
Inks for desktop applications are the lifeblood of inkjet remanufacturing and will be the focus of this article.
A Recipe for Ink
Desktop inkjet inks are aqueous (water-based). Because of this, a remanufacturer working with water-based ink can set up shop without a large capital outlay for special venting and hazardous material precautions, unlike some businesses that use solvent-based inks for industrial and specialty applications.
Desktop inks are composed of seven to 14 different chemicals. See Figure 1.
Ink quality is determined by measuring the following physical properties. These are important for the remanufacturer to consider when researching and selecting inks.
Figure 1.
Viscosity — measurement of the flow properties of ink. This impacts laydown, spread, dry time, drop size and flow.
Surface tension — the ability of a liquid to wet a surface. This is one of the most important parameters. It affects ink flow through the sponge or bladder, drop integrity, edge acuity, print sharpness and inter-color bleed.
pH — Measure of acidity of a water-based solution. It normally should be above neutral (7.0) and in the slightly basic range. Incorrect pH can cause color shifts on certain media; it may also cause damage to the cartridge or printer components.
Conductivity — Measurement of inorganic salts in the ink. In general, the value of this measurement is related more to dye purity than to any performance factor.
Color absorbance — Measurement of color shade and intensity. This affects tonal reproduction, halftones, gray tones and shade gradations.
Visual color — A colorimeter is used for quantitative analysis of color. Media, lighting and laydown can all affect the visual color of a printed sample.
Ink purity — Measurement of dissolved solids in the ink. Impurities can cause nozzle clogging and major print failure.
Dye-Based Versus Pigment-Based
Inks for inkjet cartridges are further broken down into dye-based and pigment-based. There are advantages and disadvantages to each.
Dye-based inks are made by completely dissolving liquid or powdered dye in purified water. They offer a wider variety of color selections and are easier and cheaper to make than pigment-based inks. However, dye-based inks have a tendency to soak into the paper fibers and spread out more, which can lead to problems with wicking and bleeding, as well as quicker fading.
Pigment-based inks are formed by suspending sub-micron particles in solution (called dispersion). These minute crystals reflect light and adhere to the printing medium. The pigment sits on the paper surface more readily than a dye. As a result, pigment-based inks are more lightfast and colorfast, making them preferable for archival purposes. However, the dispersion in pigment-based inks can make them more prone to nozzle clogging than dye-based inks.
The chart in Figure 2 compares different characteristics of pigment- and dye-based inks.
Figure 2.
Currently, most pigment-based inks are black, and most colored inks are dye-based, although the industry is starting to evolve towards the use of pigmented colored inks.
When remanufacturing inkjet cartridges, it is important to know which cartridges require dye-based ink and which require pigmented. It’s common for some OEM ink to remain in a cartridge to be remanufactured, even after it has been vacuum cleaned. If pigmented ink is put in a dye-based cartridge (or vice versa), the new ink could interact with the remaining old ink, causing a change in the chemical makeup. This in turn can increase the risk of cartridge failure.
There are some specialty inks available that are formulated to be used successfully in either environment. An ink supplier will be able to provide more information.
Figure 3 provides a list of some common cartridges, categorized as dye-based or pigment-based.
Figure 3.
Testing the Ink
Preferably, inks should be tested thoroughly before being used in production. To get the most out of the testing process, request a sample from the manufacturer and:
* Print comparison pages with both the test ink and OEM, using the same printer and exactly the same paper type.
* Judge them as a customer would.
* Test for blackness, crispness, dry time, color bleed and color hues.
* Print on different media and different weights of paper.
* Compare total page count (how many pages a remanufactured cartridge puts out versus the OEM).
* Let the cartridge with test ink sit for several months and then re-test.
Ink Storage
Most ink has a shelf life of approximately one year. Ideally, it should be stored at room temperature (around 72 degrees Fahrenheit/22 degrees Celsius). Extremes of heat, cold or humidity could cause changes in the ink’s chemical composition over time.
It is also important to cover any opened ink supply to protect it from contaminants. One way to accomplish this is to run the ink supply line through a hole drilled in the original cap and then screw the cap back on. See Figure 4.
Figure 4.
In Summary
As we have seen, ink chemistry and formulations can determine, at least in part, the final quality of a printed image. That makes ink selection a critical step in the remanufacturing process. Understanding ink’s basic properties, characteristics and testing mechanisms gives the remanufacturer an edge in making that decision.
Guide created: 02-20-2008 (updated 07-07-2008)
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