Compositions: coating or plastic – Coating or plastic compositions – Marking
Reexamination Certificate
1999-03-12
2001-04-10
Klemanski, Helene (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Marking
C106S031580, C106S031850, C106S031860
Reexamination Certificate
active
06214099
ABSTRACT:
RELATED APPLICATIONS
The present invention is based on Japanese Patent Application No. 10-85862, each content of which being incorporated by reference.
BACKGROUND OF THE INVENTION
1 Field of the Invention
The present invention pertains to a liquid composition that is suited for use in image formation using the inkjet recording method, an ink set combining the liquid composition and ink, and an image forming method using said liquid composition and ink set.
2 Description of the Related Art
An inkjet recording method refers to a method in which droplets of ink are expelled from small holes such that the ink will adhere to a recording medium consisting of paper, for example. For the ink used in this method, ink comprising various different coloring agents dissolved or dispersed in water or a medium comprising water and various organic solvents are generally known. Ink of various colors, i.e., yellow, cyan, magenta, black, red, blue and green, is commercially available for the reproduction of color images.
Ink used for inkjet recording is required to dry quickly in order to achieve fast recording (15 ppm or more) and printing on regular paper. In an attempt to provide ink that dries quickly, organic solvents that have a relatively high volatility have been used to improve the drying property.
However, because the inkjet method involves expulsion of ink droplets from small holes, the problem arises that the holes become clogged with dried ink. Because the improvement of the drying property and the prevention of clogging are opposing objectives, a balance between the two is currently achieved by means of a maintenance mechanism to prevent the ink from drying, but given the increasing demand for faster printing speeds, achieving these two objectives to an equal extent has become an important task.
On the other hand, U.S. Pat. No. 5,618,338, for example, proposes a technology to cause a liquid composition containing a specific substance to adhere to the image formation area, in addition to the ink, from the viewpoint of improving the quality of the recorded images, but this technology is not capable of completely achieving the two objectives described above. In addition, said patent makes no mention the balanced achievement of these objectives.
OBJECT AND SUMMARY
The present invention was made in consideration of the situation described above. Its object is to provide a liquid composition, an ink set and an image forming method that improve the drying property of the ink and prevent the clogging of the holes from which the ink is expelled.
The present invention relates to a liquid composition that is used in an image forming method that includes a step in which the liquid composition is caused to attach to an image formation area of the recording medium and a step in which the ink is provided to the recording medium by means of the inkjet recording method, s aid liquid composition including an organic solvent having a vapor pressure of 30 to 60 mmHg at 20° C. and water, wherein the ratio by weight of the organic solvent to the water (organic solvent/water) is between 95/5 and 45/55.
The present invention also relates to an ink set comprising the liquid composition and ink of at least one color.
The present invention also relates to an image forming method including a step in which the liquid composition is caused to attach to an image formation area of the recording medium and a step in which the ink is provided to the recording medium by means of the inkjet recording method.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The inventors of the present invention discovered that, with regard to a liquid composition that is used in an image forming method that includes a step in which the liquid composition is caused to attach to at least an image formation area of the recording medium and a step in which the ink is provided to the recording medium by means of the inkjet recording method, if a mixed solution including a highly volatile organic solvent and water is used as the composition, the improvement of the ink's drying property and the prevention of clogging of the nozzles may be easily achieved.
The liquid composition pertaining to the present invention comprises a liquid composition including at minimum a highly volatile organic solvent and water. For the highly volatile organic solvent, any water-soluble organic solvent having a vapor pressure of 30 to 60 mmHg, may be used without any specific limitations. For example, the solvent may comprise a lower alcohol, such as ethanol or isopropyl alcohol. If an organic solvent having a vapor pressure of less than 30 mmHg at 20° C. were used, the quick drying characteristic could not be obtained in the ink, which would create a problem. Further, if an organic solvent having a vapor pressure of over 60 mmHg were used, although the effects of the present invention, i.e., improved quick drying property of the ink and prevention of clogging of the nozzles, would be obtained, the liquid composition would dry too quickly and it would become necessary to keep it airtight inside the image forming apparatus, which would not be preferred.
The ratio by weight of the organic solvent to water (organic solvent/water) in the liquid composition pertaining to the present invention should preferably be between 95/5 and 45/55, although this range may vary depending on the type of the organic solvent used. If the ratio by weight of the organic solvent is smaller than said range in the mixture solution, it becomes difficult to obtain the quick drying property for the ink, and if said range is exceeded, the handling of the liquid composition inside the image forming apparatus may become difficult.
The liquid composition pertaining to the present invention may include a viscosity adjusting agent, a pH adjusting agent, a preservative, various surfactants, an antioxidant and an evaporation promoting agent. The additives should be 1% or less by weight.
The liquid composition may be easily obtained by simply mixing the ingredients listed above. It is preferred that the liquid composition be filtered under pressure using a membrane filter having a pore size of 0.1 &mgr;m through 1.0 &mgr;m (Fluoro Porefilter by Sumitomo Electric Industries, Ltd., for example) after the ingredients are mixed together.
The ink set pertaining to the present invention comprises the liquid composition described above and ink of at least one color selected from the group of color inks, i.e., yellow, magenta, cyan, black, red, blue and green.
The ink used in the present invention comprises at minimum a coloring agent and water, said coloring agent being dissolved or dispersed in the water. It is also acceptable if a moisture retaining agent, a viscosity adjusting agent, a pH adjusting agent, a preservative, various surfactants and an antioxidant are included where necessary. In the ink used in the present invention, a small amount of a water-soluble organic solvent may be included so that the additives will be efficiently dissolved in the water. The ink used in the present invention is explained in detail below.
The coloring agent used may comprise a dye or a pigment. As specific examples, for the yellow coloring agent used in the ink, where a dye is used, C.I. Direct Yellow 86, C.I. Acid Yellow 23 or C.I. Acid Yellow 79 may be used, and where a pigment is used, C.I. Pigment Yellow 1, C.I. Pigment Yellow 2, C.I. Pigment Yellow 3, C.I. Pigment Yellow 13, C.I. Pigment Yellow 16 or C.I. Pigment Yellow 83 may be used. But the coloring agent is not limited to these.
For the magenta coloring agent, where a dye is used, such substances as C.I. Acid Red 289, C.I. Acid Red 52 or C.I. Reactive Red 120 may be used, and where a pigment is used, such substances as C.I. Pigment Red 5, C.I. Pigment Red 7, C.I. Pigment Red 12, C.I. Pigment Red 48 (Ca), C.I. Pigment Red 48 (Mn), C.I. Pigment Red 57 (Ca), C.I. Pigment Red 112 or C.I. Pigment Red 122 may be used. But the coloring agent is not limited to these.
For the cyan coloring agent, where a dye is used, such substances as C.I. Direct Blue 86, C.I. Direc
Hotomi Hideo
Tabata Kenichi
Ueda Noboru
Ueda Takamasa
Faison Veronica F.
Klemanski Helene
McDermott & Will & Emery
Minolta Co. , Ltd.
LandOfFree
Liquid composition and ink set, and an image forming method... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Liquid composition and ink set, and an image forming method..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Liquid composition and ink set, and an image forming method... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2521532