Stock material or miscellaneous articles – Ink jet stock for printing – Plural ink receptive layers
Reexamination Certificate
2002-06-14
2004-11-30
Shewaraged, B. (Department: 1774)
Stock material or miscellaneous articles
Ink jet stock for printing
Plural ink receptive layers
C428S032170, C428S032310, C428S032350, C428S032360, C427S245000
Reexamination Certificate
active
06824843
ABSTRACT:
The present invention relates to a high quality recording medium employing a water-impermeable substrate, excellent in color reproducibility and sharpness, and particularly having a low psychometric lightness at a black printed portion, and a method for its production.
As a recording medium to be used for ink jet recording, an ink jet recording medium having various properties such as fixing property of an ink for ink jet recording, absorptivity, print density, roundness of dots, sharpness around dots, gloss, whiteness, water resistance and light resistance is developed. However, for such an ink jet recording medium, particularly for one for a photo grade, an ink jet recording medium having a high gloss, gloss and smoothness close to those of a photograph, a high print density, and excellent fixing property and absorptivity of an ink for ink jet recording, as properties of its recording surface, has been required.
However, in a case where a first porous layer is formed on a water-impermeable substrate and a second porous layer is further formed thereon, if the amount of a solvent in a coating liquid for formation of the second porous layer is in excess of the absorption of the first porous layer, no uniform surface would be formed due to bubbles from the porous layer. Further, if the amount of a solvent in a coating liquid for formation of the second porous layer is excessively smaller than the absorption of the first porous layer, the solid content concentration in the coating liquid for formation of the second porous layer rapidly increases due to water absorbing power of the first porous layer, whereby no smooth coated surface or no uniform coated surface can be formed.
Under these circumstances, it is an object of the present invention to provide a high quality ink jet recording medium having controlled surface of the second porous layer, having a high gloss, gloss and smoothness close to those of a photograph, a high print density, a high fixing property and high absorptivity of an ink for ink jet recording, and particularly excellent in color reproducibility and sharpness, and a method for producing it.
According to a first aspect of the present invention, there is provided an ink jet recording medium comprising a water-impermeable substrate, a first porous layer formed on the substrate, and a second porous layer formed on the first porous layer, wherein the psychometric lightness (L*) at a black solid printed portion with a black dye ink is at most 5.0.
According to a second aspect of the present invention, there is provided a method for producing an ink jet recording medium, which comprises coating a first porous layer containing inorganic fine particles and a binder, formed on a water-impermeable substrate, with a coating liquid containing inorganic fine particles and a binder to form a second porous layer, wherein the solid content concentration C (mass %) in the coating liquid for formation of the second porous layer satisfies the following Formulae 1 and 2:
C
≧20
D
/(
D+X/
5) Formula 1
C
≦500
D
/(
D+
5
X
) Formula 2
wherein X (g/m
2
) is the total water absorption of the first porous layer and D (g/M
2
) is the coating amount of the second porous layer after drying. The total water absorption of the first porous layer is obtained in such a manner that the area of the medium having the first porous layer formed on the water-impermeable substrate is defined, the medium is immersed in water for 60 seconds, and the mass of the medium before the immersion is subtracted from the mass after the immersion.
Of the ink jet recording medium of the present invention, the psychometric lightness (L*) at a black printed portion by solid printing with a black dye ink (hereinafter referred to simply as black printed portion) is at most 5.0, whereby the ink jet recording medium has excellent color reproducibility and sharpness at a black printed portion. L* measured at a black printed portion is preferably at most 3.0, particularly preferably at most 2.0. The psychometric lightness (L*) at a black printed portion of the ink jet recording medium of the present invention is evaluated by psychometric lightness in L*a*b* color system of JIS-Z8729 as measured by a method of JIS-Z8722 measured at a black printed portion (hereinafter referred to as L*).
In the second aspect of the present invention, it is required to adjust C in accordance with conditions of X and D at the time of forming the second porous layer on the first porous layer formed on the water-impermeable substrate, so as to obtain a recording medium having a high gloss. If C is out of the range of Formula 1, the amount of the solvent in the coating liquid for formation of the second porous layer tends to be large. Accordingly, after formation of the second porous layer, the air in the first porous layer can not adequately come out, thus causing bubbly defects on the surface of the second porous layer. If C is out of the range of Formula 2, when the first porous layer is coated with the coating liquid for formation of the second porous layer, the solvent in the coating liquid is rapidly absorbed in the first porous layer, whereby the surface of the second porous layer tends to be non-uniform. Further, the leveling property on the surface of the second porous layer tends to decrease, whereby no adequate smoothness of the surface of the second porous layer tends to be obtained. Namely, if C is out of at least one of the ranges of Formula 1 and Formula 2, smoothness of the surface of the second porous layer tends to be poor, whereby the amount of irregularly reflected light on the surface tends to increase, thus decreasing color reproducibility and sharpness at a black printed portion.
Accordingly, an ink jet recording medium formed by using the coating liquid for formation of the second porous layer, the solid content concentration of which satisfies both Formulae 1 and 2, has a high surface smoothness of the second porous layer even after a drying step. Accordingly, the amount of irregularly reflected light on the surface of the second porous layer tends to be small, reproducibility and sharpness of an image tend to be excellent, and excellent reproducibility and sharpness of an image particularly at a black printed portion can be obtained.
Now, the present invention will be described in detail with reference to the preferred embodiments.
The ink jet recording medium according to the first aspect of the present invention has such a construction that at least one ink-receiving layer (hereinafter referred to as a first porous layer) is provided on at least one side of a substrate, and another ink-receiving layer (hereinafter referred to as a second porous layer) is laminated thereon.
The substrate to be used in the present invention is required to be a water-impermeable substrate. The water-impermeable substrate may, for example, be a highly smooth polyester film of e.g. polyethylene terephthalate or polyethylene naphthalate, a synthetic paper obtained by biaxial orientation of a polyolefin, or a resin coated paper (RC paper) having a polyolefin resin coated layer.
For the ink jet recording medium of the present invention, it is required to provide at least one first porous layer between the water-impermeable substrate and the second porous layer, so as to achieve an ink jet recording medium which adequately absorbs an ink and which has more excellent ink jet recording properties. The first porous layer preferably contains a binder resin and inorganic pigment fine particles. Further, it may contain an additive such as a water resistance imparting agent, a light resistance imparting agent, a weather resistance imparting agent or a hardening agent.
The inorganic pigment fine particles contained in the first porous layer may be inorganic pigment fine particles which are insoluble or hardly soluble in water. Specifically, preferred are a synthetic amorphous silica, a xerogel obtained by removing a solvent from a silica sol, a xerogel obtained by removing a solvent from a silica sol having its s
Inoue Masahiro
Wakabayashi Hirokazu
Asahi Glass Company Limited
Shewaraged B.
LandOfFree
Ink jet recording medium and method for its production 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 jet recording medium and method for its production, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ink jet recording medium and method for its production will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3338459