Compositions: coating or plastic – Coating or plastic compositions – Marking
Reexamination Certificate
1999-02-02
2002-01-29
Klemanski, Helene (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Marking
C106S031280, C106S031480, C106S031490, C106S031500, C106S031520, C106S031600
Reexamination Certificate
active
06342096
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink-jet recording method which has high reliability and can provide an image high in optical density and good in tone representation. The ink-jet recording method according to the present invention can be preferably applied to, particularly, image forming apparatus and the like which permit the formation of images such as diagnostic images and reference images used in a medical field, in which a high optical density of image is required for a transparent base material.
2. Related Background Art
In an ink-jet recording system, an ink is ejected to apply it to a recording medium such as paper, thereby conducting recording. In particular, according to the system disclosed in 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 droplets of the ink, the formation of a high-density multi-orifice in a recording head can be realized with ease, and high-resolution and high-quality images can be recorded at high speed.
Water-soluble dyes are mainly used as coloring materials in the conventional inks used in the ink-jet recording system. However, the inks using a water-soluble dye as a coloring material involve a problem that when high-density printing is conducted on a transparent recording medium with such an ink, the maximum optical density of image is hard to achieve compared with the optical density of image in the wet silver salt method or the like in application to fields in which particularly a high transmission density of image is required, because the transparency of the coloring material is high.
In order to overcome such a problem as described above in the inks using a water-soluble dye as a coloring material, it is considered to use a coloring material having high hiding power, such as a pigment. When a pigment, for example, carbon black is used as a coloring material for obtaining high optical density of image, however, the so-called undertone of the pigment becomes conspicuous at a highlight portion, and its color tone becomes reddish in which the b* value in the CIELAB color space becomes relatively large, so that fine tone representation may not be achieved in some cases.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an ink-jet recording method by which the above-described problem, i.e., the problem of color tone at the highlight portion caused in the case where a pigment ink is used to obtain an image having a high optical density by the ink-jet recording system, can be solved, and an image good in tone representation can be provided.
Another object of the present invention is to provide a method for improving the tone property of a black image with a plurality of tones which is formed using a plurality of inks in accordance with an ink-jet recording method.
The above objects can be achieved by the present invention described below.
According to the present invention, there is thus provided an ink-jet recording method comprising applying a plurality of inks to a recording medium by an ink jet recording system to form a dual or multi-toned image on the recording medium, wherein each of the inks permits formation of such an image on a transparent recording medium whose a* and b* values of CIELAB determined by measuring CIELAB color space of the image on a transparent recording medium with a single pass, satisfy the relationship represented by the following formula (I):
(a*
2
+b*
2
)
½
≦15 (I).
According to the present invention, there is also provided a process for improving tone property of a dual toned-black image or a multi toned-black image on a transparent recording medium with a plurality of black inks by using an ink-jet recording method,
wherein each of the inks permits formation of such a single toned-black image on a transparent recording medium whose a* and b* values of CIELAB determined by measuring CIELAB color space of the single toned-black images formed with respective inks with a single pass, satisfy the relationship represented by the following formula (I):
(a
*2
+b
*2
)
½
≦15 (I).
REFERENCES:
patent: 5114477 (1992-05-01), Mort et al.
patent: 5614007 (1997-03-01), Kurabayashi et al.
patent: 5631684 (1997-05-01), Takaide et al.
patent: 5700314 (1997-12-01), Kurabayashi et al.
patent: 5910812 (1999-06-01), Yamamoto et al.
patent: 61-59911 (1979-05-01), None
patent: 61-59912 (1979-05-01), None
patent: 61-59914 (1980-02-01), None
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