Compositions: coating or plastic – Coating or plastic compositions – Marking
Reexamination Certificate
1999-10-06
2002-12-03
Klemanski, Helene (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Marking
C106S031270, C106S031600
Reexamination Certificate
active
06488751
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink set for ink jet recording which can realize images having excellent lightfastness, and an ink jet recording method using the same.
2. Background Art
Fading of color images with the elapse of time sometimes makes the color images different from the original one. One conventional method for rendering the change in images unnoticeable is to use inks having substantially the same fading rate. This is based on a thought that, since the inks fade on substantially the same level, the printed inks constituting the printed color image would fade on substantially the same level. This makes it difficult to notice the fading of the whole color image.
On the other hand, in general, many properties are required of colorants used in inks for ink jet printers. For example, dissolution or dispersion in solvents is necessary for stable ejection from the ink jet recording head and prevention of clogging. Additional properties required of the colorants include that the colorants do not deteriorate head members and fixation onto recording sheets and color development are good. In addition, safety and the like are required. The above various restrictions unfavorably limit colorants usable in inks for ink jet recording. Therefore, it is very difficult to use color inks having the same fading rate.
SUMMARY OF THE INVENTION
The present inventors have now found that, even though the inks used with ink jet printers do not have identical fading, use of a combination of the inks that have a difference in fading in the order of lightness of the inks renders the fading of a color image visually unnoticeable. Further, the present inventors have found that deposition of the inks in the order from highest to lowest of fading onto recording media can more effectively enjoy the above advantage. The present invention has been made based on such finding.
Thus, according to one aspect of the present invention, there is provided an ink set for ink jet recording, comprising two or more inks, the order from highest to lowest of fading of the inks being in the order from highest to lowest of lightness of the inks.
According to another aspect of the present invention, there is provided an ink jet recording method comprising the steps of: ejecting droplets of inks; and depositing the droplets onto a recording medium to perform printing, the inks being inks constituting the ink set according to the present invention. According to a preferred embodiment of the present invention, the inks are deposited in the order from highest to lowest of fading onto the recording medium.
Color images formed by the ink set according to the present invention, even when faded with the elapse of time, cannot visually notice the fading without difficulty. Therefore, the lightfastness of the printed images can be apparently improved. This advantage is significant in recording using ink jet printers wherein ink droplets are deposited directly onto recording media, and is more significant in ink systems using dispersed pigments.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Ink Set
The ink set according to the present invention comprises a combination of two or more inks selected so that the order from highest to lowest of fading of the inks is in the order from highest to lowest of lightness of the inks. Therefore, for example, if assume that inks A, B, and C respectively having lightnesses La, Lb, and Lc (La>Lb>Lc) are present and these are combined to constitute an ink set according to the present invention, the fading of the ink A (Fa), the fading of the ink B (Fb), and the fading of the ink C (Fc) should satisfy the following relationship: Fa>Fb>Fc.
The ink set according to the present invention preferably comprises at least a yellow ink, a magenta ink, and a cyan ink. When the order from highest to lowest of lightness of the inks contained in this ink set is the yellow ink, the magenta ink, and the cyan ink, the fading of the yellow ink (Y), the fading of the magenta ink (M), and the fading of the cyan ink (C) should satisfy the following relationship: Y>M>C. That is, the order from largest to smallest of the fading should be the yellow ink, the magenta ink, and the cyan ink.
When the ink set according to the present invention further contains a black ink in addition to the yellow ink, the magenta ink, and the cyan ink, and, in this case, when the order from highest to lowest of lightness of the inks contained in this ink set is the yellow ink, the magenta ink, the cyan ink, and the black ink, the fading of the light black ink (K), the fading of the yellow ink (Y), the fading of the magenta ink (M), and the fading of the cyan ink (C) should satisfy the following relationship: Y>M>C>K.
When the ink set according to the present invention comprises a light magenta ink and/or a light cyan ink in addition to the yellow ink, the magenta ink, and the cyan ink, and, in this case, when the order from highest to lowest of lightness of the inks contained in this ink set is the yellow ink, the light magenta ink, the light cyan ink, the magenta ink, and the cyan ink, the fading of the yellow ink (Y), the fading of the light magenta ink (Lm), the fading of the light cyan ink (Lc), the fading of the magenta ink (M), and the fading of the cyan ink (C) should satisfy the following relationship: Y>Lm>Lc>M>C.
When the ink set according to the present invention further contains a black ink in addition to the yellow ink, the light magenta ink, the light cyan ink, the magenta ink, the cyan ink, and the black ink, and, in this case, when the order from highest to lowest of lightness of the inks contained in this ink set is the yellow ink, the light magenta ink, the light cyan ink, the magenta ink, the cyan ink, and the black ink, the fading of the black ink (K), the fading of the yellow ink (Y), the fading of the light magenta ink (Lm), the fading of the light cyan ink (Lc), the fading of the magenta ink (M), and the fading of the cyan ink (C) should satisfy the following relationship: Y>Lm>Lc>M>C>K.
The “light magenta” refers to pale magenta, and the “light cyan” refers to pale cyan. The light magenta ink used in the present invention may be easily produced by a conventional method, for example, by reducing the content of a colorant (a pigment or a dye) used in the preparation of a magenta ink, or, in the case of a pigment ink, by reducing the particle diameter of the pigment used. Likewise, the light cyan ink used in the present invention may be easily produced by a conventional method, for example, by reducing the content of a colorant (a pigment or a dye) used in the preparation of a cyan ink, or, in the case of a pigment ink, by reducing the particle diameter of the pigment used.
When the ink set according to the present invention comprises an orange ink and/or a green ink in addition to the yellow ink, the magenta ink, and the cyan ink, and, in this case, when the order from highest to lowest of lightness of the inks contained in this ink set is the yellow ink, the orange ink, the magenta ink, the cyan ink, and the green ink, the fading of the yellow ink (Y), the fading of the orange ink (O), the fading of the magenta ink (M), the fading of the cyan ink (C), and the fading of the green ink (G) should satisfy the following relationship: Y>O>M>C>G.
When the ink set according to the present invention further contains a black ink in addition to the yellow ink, the magenta ink, the cyan ink, the orange ink, and the green ink, and, in this case, when the order from highest to lowest of lightness of the inks contained in this ink set is the yellow ink, the orange ink, the magenta ink, the cyan ink, the green ink, and the black ink, the fading of the black ink (K), the fading of the yellow ink (Y), the fading of the orange ink (O), the fading of the magenta ink (M), the fading of the cyan ink (C), and fading of the green ink (G) should satisfy the following relationship: Y>O>M>C>G>K.
The term “li
Klemanski Helene
Ladas & Parry
Seiko Epson Corporation
LandOfFree
Ink set for ink jet recording and ink jet recording 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 Ink set for ink jet recording and ink jet recording method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ink set for ink jet recording and ink jet recording method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2957139