From time to time we are asked the question, "Does a Universal ink jet ink exist?" This is usually directed to us or other ink manufacturers by someone who wants to use one ink for all similar applications. Theanswer in the past has always been "NO." All inks have characteristics that are specific for a certain ink jet application.
Recently, however, there have been some new thoughts on this matter. Now, the answer is "No," but with a few exceptions. Before I offer an explanation, allow me to discuss what it now takes to create an ink jet ink. The science of ink research and manufacturing has become more definitive. Routinely, new information and parameters are documented and used. Companies that invest in research and development, use this data as building blocks to position superior ink jet inks in a wide variety of applications. This database of information also allows us to compare and contrast the characteristics of different inks and then predict the performance of the inks for certain applications.
 
Ink and Ink/Printer/Substrate Characteristics
Boiling Point - The boiling point of a water-based ink is usually around 100-102p C.
Capillary Action - A method used by some ink jet systems to transfer ink from the primary reservoir to the print head. This feeding mechanism uses the natural attraction of the ink for the transfer material to keep a constant ink flow.
Capillary Train - The path the ink travels inside the reservoir as it is printed or removed.
Cartridge Type - Cartridges can have either an open or foam reservoir with either an attached or a remote printhead.
Color Density - The intensity of the color of the ink usually measured by a specific type of equipment.
Compatibility - The ability of an ink and the materials around it to work together.
Dot Overlap - The pattern the drops of ink make as it is printed.
Dry Time - The time it takes for an ink to withstand incidental contact or rubbing without smearing.
Evaporation Rate - The speed at which water is taken from the orifice of the printhead. This can affect print.
Freezing Point - The point at which a liquid ink turns into a solid. This is usually around 30-32p F for water-based ink.
Humectant - An ingredient added to an ink that assists in keeping the orifices of an ink jet cartridge open by drawing moisture from the air.
Ink Base - For ink jet cartridges, the base or major solvent of the ink is water. Other ink bases include alcohol and oils.
Ink Coverage - The ability of an ink to mask or cover a substrate, usually relating to the opacity and evenness of print.
Ink Flow - The tendency of an ink to travel through the reservoir to the printhead.
Ink Settling - A term to describe the precipitation of particles in a pigmented ink.
Ink Type - This term usually pertains to the colorant type either being dye or pigment.
Lambda Max - The wavelength at which a dye absorbs the most light. This is found by using a UV Visible Spectrophotometer.
Lightfastness - The durability of the print intensity when exposed to light. When an ink is lightfast, it is fade resistent.
Meniscus Shape - Term describing the interface of an ink at the orifice of the ink jet printer. It is caused by the degree of attraction the ink has to the material of the printhead.
Particle Distribution - The number and size of particles in a pigmented ink.
pH - A measure of the acid or basic character of the ink. The pH values are in a range of 0-14 with a low pH being acidic and a high pH being basic.
Print Clarity - Term describing the cleanness or definition of a print.
Printer Type - Typical ink jet printers employ either bubble jet or piezo printing technology.
Printhead Frequency - This term describes the speed at which a print head shoots drops of ink at any given time. A typical frequency or drop rate for ink jet cartridges would be 2-5 Khz (2,000-5,000 drops/second).
Reservoir Type - The container or storage area for the ink in an ink jet system. It can vary greatly in size, content, and construction.
Shelf Life - The usable print life of an ink after storage.
Specific Gravity - The density of a material at a given volume.
Starting - The term describing the ability of a cartridge to completely print the first line (or sometimes the first character) after a waiting period.
Strike Through - A term used to describe the act of an ink penetrating through a substrate. This can be seen by looking at the back of the substrate after printing.
Surface Tension - The attraction of a liquid for any material with which it is in contact. A high surface tension means low attraction and a low surface tension means a high degree of attraction.
Waterfastness - The resistance of an impression to dilution or removal by water. A waterfast ink has a reduced tendency to wick, feather, or be washed away.
Wetting Characteristics - This relates to the ability of an ink to penetrate into an ink reservoir and especially the foam structure.
Wicking/Feathering - A term used to describe the tendencies of an ink to travel in uneven patterns along the structure or fiber of a given substrate.
UV Visible Spectrophotometer - An analytical instrument used to measure the absorption of light by a colorant at certain wavelengths.
Viscosity - A measure of the relative thickness of a liquid. Lower viscosities are like water while higher viscosities are like syrup.
As you can see, the criteria is extensive and involved. Additionally, as these are researched, it becomes evident that some of them are even intertwined. If you change one, others are also affected.
For example, if the surface tension of an ink is lowered, some positive results may be seen. It may enhance the ability of the ink to penetrate the foam and improve the capillary action of the ink in that cartridge. But, lower surface tensions can also cause the ink to wick and feather excessively on certain substrates. Or, if you change or lower the humectant content in the ink, it could improve or shorten ink dry times on certain substrates. But, this lower content could increase the evaporation rate of the ink in the orifices of the printhead and cause voids when the cartridge first starts to print.
So, since all of these items are important and are checked as inks are developed, we continue to have a deeper and more vast understanding of the support data. Now, about universal inks. While no one ink can be used for all applications, we know from our research and customer contact, that some inks can be used for more applications than originally intended.
Here are two instances of note:
1) A large volume end-user wanted a brighter, more vivid color out of a certain cartridge type. They were using an OEM color-matched ink and wanted to know if another ink was available that could produce a brighter or more vivid color. We reviewed the research information we have amassed on a variety of inks to find some that were similar in most characteristics but were brighter or more intense in color. We were reasonably sure that the inks would perform satisfactorily and asked the customer to field test our recommendations. The customer liked results and now has inks that are "universal" or that were designed for one application but able to be used in others.
2) A reinker wanted to supply a wide variety of reinking capabilities but did not want to carry the inventory for some of its lower volume or less requested products. When the customer contacted us, we once again reviewed the data we had collected on ink characteristics and found families of inks that had similar characteristics but were slightly different in color shade or intensity. Most commonly requested are the Epson Stylus Color cartridges. When these inks were tried by the customer, acceptable results for many applications were realized. So, once again this Reinker has inks that are "universal" or used in more than one application.
So, even when we try to encourage using a specific ink for a specific application, customers and end-users understand their businesses and their customer base. They make their own choices and know what is acceptable to their end-users. While one ink is never going to work for all applications, one can be used for several.