Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1999-04-01
2004-09-14
Shosho, Callie (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C523S161000, C523S205000, C106S031280, C106S031600
Reexamination Certificate
active
06790878
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink which is suitable for use in ink-jet recording, excellent in reliability, and capable of providing an image having a high optical density even on plain paper and also forming an image having excellent water fastness and resistance to line marker, and an ink set, ink cartridge, recording unit, image recording apparatus and image recording process using such an ink. The present invention also relates to an ink which is suitable for use in ink-jet recording, excellent in reliability, capable of providing an image having a high optical density even on plain paper, forming an image having excellent water fastness and resistance and further extremely effectively preventing bleeding at boundaries between different colors of a multi-color image on a recording medium when the multi-color image is formed together with other color inks by an ink-jet recording method, and an ink set, ink cartridge, recording unit, image recording apparatus and image recording process using such an ink.
2. Related Background Art
An ink-jet recording method is a system in which recording is conducted by ejecting an ink to apply the ink to a recording medium such as paper. According to an ink-jet recording system disclosed in, for example, Japanese Patent Publication Nos. 61-59911, 61-59912 and 61-59914, in which an electrothermal converter is used as an ejection-energy supply means to apply thermal energy to an ink so as to generate bubbles, thereby ejecting the ink, the formation of a high-density multi-orifice in a recording head can be realized with ease, and a high-resolution and high-quality image can be recorded at high speed. Therefore, such an ink-jet system is a main system for ink-jet recording methods put to practical use at present.
By the way, for example, a water-soluble dye is used as a coloring material in an ink used in such an ink-jet recording method. However, images recorded with such an ink are required to more improve their water fastness, and resistance to line marker on plain paper.
When a multi-color printing is conducted on plain paper, there is also a demand for further reduction in the so-called color bleed caused by mixing of inks of different colors at boundaries between the inks in an image formed with such inks.
A great number of means for overcoming such problems, particularly, improving the optical density and water fastness of recorded images have been proposed to date. As one of the solutions thereof, it is proposed to prepare an ink containing a pigment as a coloring material and dispersed in water. For example, an ink using carbon black as a coloring material permits the provision of an image having a high optical density and excellent water fastness by ink-jet recording. However, such a recorded image still leaves room for improvement in rub-off resistance and resistance to line marker on plain paper in particular.
As a technique for overcoming such problems as described above, it has been known to improve image fixing ability by adding a resin in the ink. For example, Japanese Patent Application Laid-Open No. 3-172362 discloses a technique wherein a cationic emulsion, in which resin particles are dispersed as a fixing agent, is contained in an ink comprising a dye or pigment as a coloring material to improve the fixing ability of the ink on a recording medium. Japanese Patent Application Laid-Open No. 8-239610 discloses a water-based pigment composition for ink-jet, comprising a pigment, a colored resin and a humectant as essential components. It is also disclosed that a print excellent in both coloring ability and water fastness can be provided by such a composition.
SUMMARY OF THE INVENTION
According to the extensive study of the aforementioned prior art by the present inventor, since the upper limits of amounts of a pigment and a resin, which can be contained in an ink, are naturally defined when the ejection stability of the ink is taken into consideration, it is inevitable to choose the amount of the pigment, which affects the optical density of a recorded image, and the amount of the resin, which affects the image fixing ability of the ink, in terms of the balance between the trade-off characteristics, i.e., the optical density and the image fixing ability. Therefore, the present inventor has concluded that it cannot be yet said under the circumstances that the pigment inks proposed to date fully make the best use of merits obtained by using a pigment as a coloring material.
More specifically, Japanese Patent Application Laid-Open No. 8-239610 explains in the specification thereof that the colored resin is a dispersion of a resin colored by a dye. According to the preparation process of the colored resin described in the Example thereof, a dye is first added to an emulsion of a resin, and the mixture is heated to about 80° C. and then cooled, thereby preparing the colored resin. However, in page 4, left column, lines 38 to 41 of this patent specification, it is described that “In order for the dye to be sufficiently taken in the resin, the amount (of the dye) is preferably 10 parts or less, particularly 8 parts or less, per 100 parts of the resin”. In each of the preparation processes described in Preparation Examples 8 to 13 of the specification, a mixing proportion of the dye to the solid resin content in the emulsion polymer is described as about 1:10 to 1:12 (dye:resin). According to the investigation by the present inventor, it has however been concluded that, when such a colored resin as described in Japanese Patent Application Laid-Open No. 8-239610 is used, such a proportion of the dye to the resin as described in the specification may not be said in some cases to be sufficient to compensate for a reduction in an optical density, due to a reduction of amount of a coloring material which can be contained in an ink, accompanied by the addition of the resin to the pigment ink for the purpose of improving the fixing ability of the ink to recording media. Further, it is inferred that when the colored resin is intended to added to such an extent that a sufficient optical density is achieved, the colored resin must be added in such an amount that departs from a range in which an ink-jet ink can be precisely ejected by an ink-jet recording system. As described above, from the investigations as to the prior art, the present inventor has reached a conclusion that the development of a new technique entirely different from the conventional techniques is required for further improvements in optical density and image fixing ability in pigment inks.
Therefore, the present inventor has carried out a further investigation. As a result, a technique which can solve the problems on inks containing a pigment while making the best use of the merits obtained by using the pigment as a coloring material has been found, thus leading to completion of the present invention. Similarly, as the result of the investigation by the present inventors, a technique which can solve the problems on inks containing a pigment while making the best use of the merits obtained by using the pigment as a coloring material, and extremely effectively prevent bleeding when applied to multi-color printing has also been found, thus leading to completion of the present invention.
It is an object of the present invention to provide an ink which can provide an image high in optical density and excellent in rub-off resistance, water fastness and resistance to line marker, and exhibits excellent ejection stability from a recording head when used in ink-jet recording.
Another object of the present invention is to provide an ink which can provide an image high in optical density and excellent in rub-off resistance, water fastness and resistance to line marker, has excellent ejection stability from a recording head when used in ink-jet recording, and moreover can extremely effectively reduce bleeding when used in a multi-color printing.
A further object of the present invention is to provide an image recording process
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Middleton Y.
Shosho Callie
LandOfFree
Ink, ink set, ink cartridge, recording unit, image recording... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ink, ink set, ink cartridge, recording unit, image recording..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ink, ink set, ink cartridge, recording unit, image recording... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3232256