Stock material or miscellaneous articles – Ink jet stock for printing – Particles present in ink receptive layer
Reexamination Certificate
2001-09-24
2004-02-24
Kelly, Cynthia H. (Department: 1774)
Stock material or miscellaneous articles
Ink jet stock for printing
Particles present in ink receptive layer
C428S032240, C428S032250
Reexamination Certificate
active
06696118
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a recording medium suitable for forming a print having texture and image quality of a silver halide photograph by a method of applying droplets of recording liquid such as ink, particularly by an ink-jet recording method, and an image forming method utilizing such recording medium.
2. Related Background Art
The ink-jet recording method is to record an image or a character by causing a micro droplet of liquid (recording liquid) such as ink to fly by various working principles and applying such micro droplet to a recording medium such as paper it has advantages of large flexibility in the recording pattern and not requiring a development process, and is rapidly spreading not only to the stand-alone printer but also the output unit in information equipment such as copying apparatus, word processors, facsimile apparatus, plotters etc. Also various imaging equipment of high performance such as digital cameras, digital video cameras, scanners etc. are recently commercialized inexpensively and a printer utilizing the ink-jet recording method is becoming employed advantageously for the output of image information obtained by such imaging equipment, in combination with the popularization of the personal computer. Based on such background, it is being desired to output an image comparable to that of the silver halide photograph or the multi-color press printing, in a simpler manner by the ink-jet recording method.
In order to meet such requirement, there have been achieved improvements in the structure of the printer itself and in the recording method toward a higher recording speed, a higher definition and higher image quality in full-color recording, and there are being actively investigated improvements on the structure and characteristics of the recording medium.
For the recording medium to be employed for example in the ink-jet recording, there have already been proposed the media of various configurations. For example, the Japanese Patent Application Laid-open No. 52-9074 discloses a recording medium provided, as an ink-receiving layer, with a layer having a void and consisting principally of a silica pigment of a large specific surface area in order to increase the ink absorbing rate, and the Japanese Patent Application Laid-open No. 63-22997 discloses a recording medium in which the void of the pigment layer constituting the ink-receiving layer is regulated. Also the Japanese Patent Applications Laid-open Nos. 55-51583 and 56-157 teach mixing of powdered amorphous silica in order to improve the ink absorptivity of the ink-receiving layer and to obtain a high print density and print dot without bleeding.
For the component of the ink receiving portion in the recording medium, alumina hydrate is attracting attention in recent years, because alumina hydrate provides advantages such as a high coloring ability and an image of high gloss owing to the fact that the alumina hydrate has a positive charge to improve the fixability of the dyes in the ink.
With respect to the recording medium utilizing such alumina hydrate, for example U.S. Pat. Nos. 4,879,166 and 5,104,730 and the Japanese Patent Applications Laid-open Nos. 2-276670, 4-37576 and 5-32037 disclose a recording medium having, as the ink-receiving layer, a layer containing alumina hydrate of pseudo-boehmite structure, while the Japanese Patent Application Laid-open No. 10-94754 discloses a recording medium containing particles of alumina hydrate in the ink-receiving layer.
Also the Japanese Patent Application Laid-open No. 11-1060 discloses a recording medium having a porous layer containing barium sulfate and a layer containing non-oriented alumina hydrate in succession in this order as the ink-receiving layer on a base material in order to increase the ink absorption rate thereby preventing the beading phenomenon and achieving excellent print quality. Also for achieving high ink absorptivity and high gloss at the same time, the Japanese Patent Application Laid-open No. 6-79967 discloses a recording medium including a layer containing alumina hydrate by cast coating. Also the Japanese Patent No. 2686670 discloses to form a two-layered ink-receiving layer consisting of an upper layer and a lower layer wherein the upper layer is principally composed of aluminum oxide of a large specific surface area and the lower layer is principally composed of a pigment of a small specific surface area, thereby obtaining a high image density.
In these recording media, there are being proposed various methods in order to further increase the image density and the color saturation. For example there is proposed a method of adding a cationic agent to retain the dye in the vicinity of the surface or a method of increasing the ink shot-in quantity to the recording medium thereby raising the dye density. However, in the method of increasing the ink shot-in quantity, there is required an even larger ink absorptivity in the ink receiving portion of the recording medium. For this purpose there is being tried to employ a pigment of a large pore volume thereby forming a structure having larger voids for absorbing and retaining the ink in the ink-receiving layer or to employ an ink-absorbing high molecular material for constituting the ink-receiving layer, but the formed dot may become turbid for example by random light reflection whereby the desired image density or gloss may not be attained. Also in order to increase the ink absorptivity, it is often necessary to increase the coating thickness of the ink-receiving layer, and there has to be adopted a costly method both in the materials and the manufacturing steps.
Also the method of adding the cationic agent is certainly capable of retaining the dye in the vicinity of the surface of the recording medium thereby increasing the image density, but the fastness of the image to light or ozone may not be sufficient depending on the composition of the ink.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a recording medium having excellent surface gloss, an extremely high print image density and reduced deterioration of the print image with age by light or by ozone at a low cost, and to minimize the time required for color stabilization after printing.
The above-mentioned object can be attained, according to the present invention, by a recording medium provided with a base material and an ink-receiving layer provided thereon, wherein the ink-receiving layer is composed of an upper layer containing an aluminum-based pigment and a lower layer containing an aluminum-based pigment having a BET specific surface area larger than that of the aluminum-based pigment in the upper layer.
Also according to the present invention, there is provided an image forming method which is featured by forming an image by applying a recording liquid according to the recording information to a surface formed by the ink-receiving layer of the recording medium of the above-described configuration.
The present invention can provide a recording medium having excellent surface gloss, an extremely high print image density and reduced deterioration of the print image with age by light or by ozone at a low cost, and to minimize the time required for color stabilization after printing.
The color stabilization mentioned in the present invention indicates the following phenomenon. In case of printing on a recording medium having a receiving layer principally composed of micro particles as in the configuration of the present invention, there is generated, immediately after the printing operation, a phenomenon that the receiving layer becomes turbid by the absorption of solvent therein whereby the developed color also becomes turbid. Such turbidity in color is resolved by the evaporation of the solvent and by a shift from the receiving layer to a lower layer, whereby the color density becomes stable in time. Such phenomenon is called color stabilization.
Also since an extremely high image density can be obtained in the image formation o
Asaoka Masanobu
Misuda Katsutoshi
Onuma Kenji
Kelly Cynthia H.
Shewareged B.
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