Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
2000-09-01
2001-11-27
Nguyen, Thinh (Department: 2861)
Incremental printing of symbolic information
Ink jet
Controller
C014S046000
Reexamination Certificate
active
06322188
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a recording method using yellow ink compositions, and more particularly to an ink jet recording method using yellow ink compositions.
2. Background Art
Various properties are required of images produced by ink compositions. One of them is lightfastness. When color images are formed using ink compositions, it is common practice to use at least magenta, yellow, and cyan inks. These inks should satisfy properties commonly required of ink compositions, for example, no change in composition and properties during storage. Additional requirements to be satisfied are such that sharp images are formed on recording materials and there is no deterioration in images during storage for a long period of time.
Further, in color images produced by a plurality of ink compositions, the presence of only one color having poor lightfastness leads to a change in hue of images and consequently extremely deteriorates the quality of color images. Thus, more controlled lightfastness is required of color ink compositions.
In recent years, ink jet recording printers have become widely spread. The ink jet recording method is a printing method wherein droplets of an ink composition are ejected and deposited on recording media, such as paper, to perform printing. The feature of the ink jet recording method is that images having high quality with high resolution can be printed at a high speed by means of a relatively inexpensive apparatus. In particular, color ink jet recording apparatuses can realize improved image quality, and have also become used as an output device for photographs and as a digital printer, a plotter, a CAD output device and the like. Images printed by means of ink jet recording printers, which have become widely used in the art, are considered utilizable in various forms. In particular, photograph-like prints are considered to be placed for display in a place exposed to light emitted from a fluorescent lamp or direct sunlight in the open or the like for a long period of time. Therefore, lightfastness is a very important property requirement to be satisfied by images produced by the ink jet recording method.
C.I. Pigment Yellow 74 has hitherto been widely used as a colorant for yellow ink compositions. Among pigment-based colorants, this pigment has exceptionally good yellow color development. However, there is still room for improvement in lightfastness.
Japanese Patent Laid-Open No. 25440/1998 proposes an ink composition for ink jet recording, containing C.I. Pigment Yellow 154. This publication, however, discloses neither the use of C.I. Pigment Yellow 74 in combination with C.I. Pigment Yellow 109, 110, 128, 150, or 154 nor advantages provided by this combination.
SUMMARY OF THE INVENTION
The present inventors have now found that combining a yellow ink containing C.I. Pigment Yellow 74 with a yellow ink containing C.I. Pigment Yellow 109, 110, 128, 150, or 154 under certain conditions for use in printing can significantly improve the lightfastness of yellow images. The present invention has been made based on such finding.
Accordingly, it is an object of the present invention to provide an image recording method which can form yellow images possessing excellent lightfastness and color development.
The image recording method according to the present invention is an image recording method using at least an ink composition containing C.I. Pigment Yellow 74 and a second yellow ink composition containing at least one yellow pigment selected from the group consisting of C.I. Pigment Yellow 109, 110, 128, 150, and 154, said method comprising the steps of: printing a high-density yellow portion using the ink composition containing C.I. Pigment Yellow 74; and printing a low-density yellow portion using an ink composition including the second yellow ink composition.
DETAILED DESCRIPTION OF THE INVENTION
The image recording method according to the present invention is a recoding method using an ink composition. Recording methods using an ink composition include, for example, an ink jet recording method, screen printing, recording methods with writing implements, such as pens, and other various printing methods. The present invention, particularly when applied to the ink jet recording method, can exhibit significant effect.
The recording method of the present invention uses at least an ink composition containing C.I. Pigment Yellow 74 and a second yellow ink composition containing at least one yellow pigment selected from the group consisting of C.I. Pigment Yellow 109, 110, 128, 150, and 154. In an image to be printed, a high-density yellow portion is printed using the ink composition containing C.I. Pigment Yellow 74, and a low-density yellow portion is printed using the second yellow ink composition. The image recording method according to the present invention can realize yellow images possessing excellent color development and lightfastness.
According to a preferred embodiment of the present invention, the high-density yellow portion is defined as a portion corresponding to a yellow density provided by printing an ink composition containing C.I. Pigment Yellow 74 at not more than 100% duty to more than 70% duty, and the low-density yellow portion is defined as a portion corresponding to a yellow density provided by printing an ink composition containing C.I. Pigment Yellow 74 at not more than 70% duty.
According to another preferred embodiment of the present invention, a medium-density yellow portion is printed using the ink composition containing C.I. Pigment Yellow 74 in combination with the second yellow ink composition. Preferably, a high-density yellow portion is defined as a portion corresponding to a yellow density provided by printing an ink composition containing C.I. Pigment Yellow 74 at not more than 100% duty to more than 75% duty, a low-density yellow portion is defined as a portion corresponding to a yellow density provided by printing an ink composition containing C.I. Pigment Yellow 74 at not more than 65% duty, and a medium-density yellow portion is defined as a portion corresponding to a yellow density provided by printing an ink composition containing C.I. Pigment Yellow 74 at not more than 75% duty to more than 65% duty. The high-density yellow portion is printed using the ink composition containing C.I. Pigment Yellow 74, the low-density yellow portion is printed using the second yellow ink composition, and the medium-density yellow portion is printed using the ink composition containing C.I. Pigment Yellow 74 in combination with the second yellow ink composition. According to this embodiment, yellow images possessing better color development and lightfastness can be realized.
The unit “duty” used herein refers to a unit of a value D defined and calculated by equation (I):
D
=
number
of
actually
printed
dots
longitudinal
resolution
×
transverse
resolution
×
100
(
duty
)
(
I
)
The yellow ink composition used in the present invention contains as a colorant C.I. Pigment Yellow 74 or C.I. Pigment Yellow 109, 110, 128, 150, or 154. The formulation of the ink composition except for the colorant may vary depending upon printing methods and recording methods.
According to a preferred embodiment of the present invention, the upper limit of the content of C.I. Pigment Yellow 74 as the colorant according to the present invention is not more than 10% by weight, more preferably not more than 7% by weight. The lower limit of the content of C.I. Pigment Yellow 74 is preferably not less than 1% by weight, more preferably not less than 2% by weight. For C.I. Pigment Yellow 74 or C.I. Pigment Yellow 109, 110, 128, 150, or 154, the upper limit of the content thereof is preferably not more than 10% by weight, more preferably not more than7% by weight. The lower limit of the content thereof is preferably not less than 1% by weight, more preferably not less than 2% by weight.
Ladas & Parry
Nguyen Thinh
Seiko Epson Corporation
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