subject: advantages of printing inks [print this page] advantages of printing inks advantages of printing inks
Ink-jet printers are known in the art and have advantages over other printing techniques, such as freedom from noise and attainment of high-speed printing, high-quality printing, and color printing. In the ink-jet printing process, an ink is compressed by an electromechanical transducing-vibration or electrothermal transducing-bubble and a high-pressure ink particle is then ejected from a nozzle for printing.
A disadvantage of ordinary inks used in this process is that ordinary ink contains dissolved gases which upon compression from bubbles or bubble nuclei. This results in blank spots in the printing known as the "missing dot" condition.
For this reason, ink-jet printing inks have been subjected to treatment, such as deaeration or fine filtration, to remove bubble nuclei, and then stored in a bag or vessel having low air permeability.
The disadvantage of these treatment and storage methods is that after a period of time, and particularly when the ink is exposed to high temperatures, bubbles still form in the ink notwithstanding the initial deaeration. Thus, after a period of time or exposure to high temperatures, the ink develops the same problems as untreated ink, i.e. an inability to be uniformly ejected from the nozzle. Thus, the prior art inks for ink-jet printers are subjected to limitations of time and temperature which affect the transportation, shelf-life, storage, and use of the ink.
Accordingly, an ink-jet printing ink which can perform in an ink jet printer after long periods of time and at high temperatures is desired.
SUMMARY OF THE INVENTION
Generally speaking, in accordance with the instant invention, an ink-jet printing ink having a nitrite ion concentration in the ink of between 0.2 to 10 parts per million (ppm) is provided In a particularly preferred embodiment, the ink-jet printing ink includes a dye having at least one azo linkage in the molecular structure and has a nitrite ion concentration in the ink of between 0.2 to 10 ppm.
Accordingly, it is an object of the instant invention to provide an improved ink-jet printing ink.
Another of the object of the instant invention is to provide and ink-jet printing ink which resists the formation of bubbles over extended periods of time.
A further object of the instant invention is to provide an ink-jet printing ink which resists a formation of bubbles at high temperatures.
An additional object of the subject invention is to provide a ink-jet printing ink which can be transported over long distances or at high temperatures while resisting the formation of bubbles.
Yet another object of the instant invention is to provide an ink-jet printing ink which has a long shelf life.
Still another object of the instant invention is to provide an ink-jet printing ink which is capable of being stored over long periods of time and may therefore be dispensed in larger volumes without the formation of bubbles.
Yet another object of the instant invention is to provide an ink-jet printing ink which is capable of functioning in ink-jet printers, which operate at high temperatures, without the formation of bubbles.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.
The invention accordingly comprises a composition of matter possessing the characteristics, properties, and the relation of constituents, the several steps and the relation of one or more of such steps with respect to each of the others, and the article possessing the features, properties, and the relation of elements, which are exemplified in the following detailed disclosure and the scope of the invention will be indicated in the claims.
