Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
2002-03-11
2004-04-20
Meier, Stephen (Department: 2853)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
C347S095000, C106S031130, C106S031270
Reexamination Certificate
active
06722765
ABSTRACT:
FIELD OF THE INVENTION
The present invention is drawn to the area of ink-jet imaging. More specifically, the present invention is drawn to ink-jet ink vehicles that are adapted for use in low dye load inks, contain no salts, and provide low orifice plate puddling.
BACKGROUND OF THE INVENTION
In recent years, computer printer technology has evolved to a point where very high resolution images can be transferred to various types of media, including paper. One particular type of printing involves the placement of small drops of a fluid ink onto a media surface in response to a digital signal. Typically, the fluid ink is placed or jetted onto the surface without physical contact between the printing device and the surface. Within this general technique, the specific method that the ink-jet ink is deposited onto the printing surface varies from system to system, and can include continuous ink deposit and drop-on-demand ink deposit.
With regard to continuous printing systems, inks used are typically based on solvents such as methyl ethyl ketone and ethanol. Essentially, continuous printing systems function as a stream of ink droplets are ejected and directed by a printer nozzle. The ink droplets are directed additionally with the assistance of an electrostatic charging device in close proximity to the nozzle. If the ink is not used on the desired printing surface, the ink is recycled for later use. With regard to drop-on-demand printing systems, the ink-jet inks are typically based upon water and solvents such as glycols. Essentially, with these systems, ink droplets are propelled from a nozzle by heat or by a pressure wave such that all of the ink droplets ejected are used to form the printed image.
There are several reasons that ink-jet printing has become a popular way of recording images on various media surfaces, particularly paper. Some of these reasons include low printer noise, capability of high-speed recording, and multi-color recording. Additionally, these advantages can be obtained at a relatively low price to consumers. However, though there has been great improvement in ink-jet printing, accompanying this improvement are increased demands by consumers in this area, e.g., higher speeds, higher resolution, full color image formation, increased stability, etc.
In general, ink-jet inks are either dye- or pigment-based inks. Both are typically prepared in an ink vehicle that contains the dye and/or the pigment. Dye-based ink-jet inks generally use a liquid colorant that is usually water-based to turn the media a specific color. Conversely, pigmented inks typically use a solid or dispersed colorant to achieve color.
Many properties that are desirable for ink-jet printing include good edge acuity and optical density of an image on a media substrate, good dry time of the ink on the substrate, adhesion to the substrate, lack of deviation of ink droplets when fired, presence of all dots, resistance of the ink after drying to water and other solvents, long-term storage stability, good dot size and dot gain, color-to-color bleed alleviation, acceptable coalescence, long term reliability without corrosion or nozzle clogging, good light fastness, good wet fastness, low humid hue shift, and other known properties. Many inks are known to possess some of the above described properties. However, few inks are known that possess all of these properties, since an improvement in one property often results in the degradation in another property. Accordingly, investigations continue into developing ink formulations that have improved properties and that do not improve one property at the significant detriment of another. However, many challenges still remain to further improve the image quality and lightfastness of ink-jet prints without sacrificing pen performance and reliability.
SUMMARY OF THE INVENTION
It has been recognized that the use of certain vehicle components in certain combinations provide a non-reactive ink vehicle that works well with low dye load magenta and cyan dyes, and medium dye load black dyes. This is particularly useful when such ink vehicles (with their respective dye component) are used in an ink-jet pen that is designed to share a service station with a pen containing acrylate dispersed pigment-based ink. Because the ink vehicles of the present invention are non-reactive with these and other ink-jet inks, the sharing of a service station does not result in increased orifice crusting.
In accordance with principles of an embodiment of the present invention, a non-reactive ink-vehicle for low dye-load ink-jet inks can comprise an effective amount of water; from 1% to 3% by weight of a 1,5-pentanediol co-solvent; from 7.5% to 15% by weight of a trimethylolpropane co-solvent; and from 5% to 8% by weight of a third co-solvent, with the proviso that the ink-vehicle comprise at least 20% by weight of total co-solvents.
In an alternative embodiment, a non-reactive ink-vehicle for low dye-load ink-jet inks can comprise an effective amount of water; from 1% to 3% by weight of a 1,5-pentanediol co-solvent; from 7.5% to 15% by weight of a trimethylolpropane co-solvent; and from 0.05% to 0.25% of a buffer consisting essentially of 2-amino-2-(hydroxymethyl)-1,3-propanediol.
A system having swappable ink-jet pens for use in a single service station can comprise a first ink-jet pen containing a pigment-based ink-jet ink; a second ink-jet pen containing a dye-based ink-jet ink that is non-reactive with the pigment-based ink-jet ink; and a single service station configured for servicing the first ink-jet pen and the second ink-jet pen. Preferably, the present system can function by utilizing swappable pens wherein substantially no reaction between the pigment-based ink-jet ink and the dye-based ink-jet ink occurs at the service station, the first ink-jet pen, or the second ink-jet pen upon swapping the first ink-jet pen for the second ink-jet pen, or vice versa.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
Before the present invention is disclosed and described, it is to be understood that this invention is not limited to the particular process steps and materials disclosed herein because such process steps and materials may vary somewhat. It is also to be understood that the terminology used herein is used for the purpose of describing particular embodiments only. The terms are not intended to be limiting because the scope of the present invention is intended to be limited only by the appended claims and equivalents thereof
It must be noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the content clearly dictates otherwise.
As used herein, “effective amount” refers to the minimal amount of a substance or agent, which is sufficient to achieve a desire effect. For example, an effective amount of a “surfactant” is the minimum amount required in order to create a dye-based ink-vehicle, while maintaining properties in accordance with embodiments of the present invention.
As used herein, “liquid vehicle” or “ink vehicle” refers to the vehicle in which colorant is placed to form an ink. Many ink vehicles and vehicle components are known in the art. However, the use of specific components at specific amounts can provide improved ink-jet ink characteristics. Typical ink vehicles can include a mixture of a variety of different agents, such as surfactants, solvents, co-solvents, buffers, biocides, sequestering agents, viscosity modifiers, surface-active agents, and water.
“Non-reactive ink-vehicle” refers to ink vehicles that do not contain reactive salts. However, dyes used in conjunction with non-reactive ink-vehicles can be a salt, provided the salt content is low enough that the ink-jet ink formulation is substantially non-reactive.
With this in mind, the present invention is drawn to the area of ink-jet imaging. More specifically, the present invention is drawn to ink-jet ink vehicles that are adapted for use in low dye load inks, contain no salts, and provide low orifice plate puddling. Particu
Rolly Luanne J.
Thierheimer Jr. Charles L
Tyrell Paul
Hewlett--Packard Development Company, L.P.
Meier Stephen
Shah Manish
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