Stock material or miscellaneous articles – Structurally defined web or sheet – Discontinuous or differential coating – impregnation or bond
Reexamination Certificate
1999-10-06
2002-10-29
Kelly, Cynthia H. (Department: 1774)
Stock material or miscellaneous articles
Structurally defined web or sheet
Discontinuous or differential coating, impregnation or bond
C428S212000, C427S152000
Reexamination Certificate
active
06472053
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an ink jet recording material which can meet basic requirements for characteristics of a recording material, including high ink absorbency, vivid ink coloration and excellent keeping quality. More particularly, the invention concerns an ink jet recording sheet having high surface gloss, causing only a slight drop in gloss by recording and enabling the recording of high-grade images. Further, the invention relates to a method of effectively ensuring satisfactorily high surface gloss for the ink jet recording sheet having excellent properties as mentioned above.
BACKGROUND OF THE INVENTION
The ink jet recording is an art of jetting out fine ink drops on any of various working principles and making them adhere to a recording material, such as a recording paper, to record pictures and letters. This art enables a recording apparatus to be operated at a high speed and with a low noise and to easily form full color images, and further requires no processing with chemicals, such as development and fixation. Therefore, the use of ink jet recording systems has been spreading rapidly.
Moreover, the use of multicolor ink jet recording arts enables the formation of high-grade color images comparable to the images formed by multicolor graphic arts utilizing plate-making processes or those formed by color photography, and that at a low price in the case of printing a small number of copies. In recent years, therefore, the ink jet recording arts have come to be also utilized in the field of recording full-color images.
For the purpose of making it possible to use woodfree paper and coated paper, which are generally used for graphic arts and note-taking, as recording materials in the ink jet recording art, examinations of recording apparatus and ink composition have so far been made from various aspects. On the other hand, recent remarkable improvements in performance of ink jet recording apparatus, as seen from substantial increases in recording speed and definition and/or the achievement of full-color recording, have expanded the potential of ink jet recording arts, and thereby new uses have been created. Such progress in the recording apparatus side has come to require ink jet recording materials to have higher-grade recording suitability. Thus, higher levels of qualities than usual have come to be requested for recording materials.
In addition to the conventional two requirements, one being excellent image quality and the other no gloss decrease in the image-recorded area, the recording suitability enabling the recording of images with high-grade quality equivalent to that of color photographic paper is required for ink jet recording materials nowadays. In order to meet such a new requirement, it is necessary to confer higher gloss than ever on the surface of ink jet recording material itself and to ensure the glossiness equivalent to that of photographic paper surface in both the background and image-recorded areas. These qualities required for recorded images are expressed plainly in a phrase “photographic style quality”, and widely known now.
The properties the recording material is required to have include (i) ensuring a high density, a circular form and coloration with a bright-and-vivid tone in individual ink dots constituting the images recorded on the recording material, (ii) enabling high-speed drying of ink to cause neither running nor blurring of the ink even when a plurality of ink dots are overlapped on the recording material surface, and (iii) enabling moderate diffusion of ink dots in the horizontal direction and ensuring a smooth and clear circumference in the individual ink dots.
Moreover, it becomes an important factor in forming images of high-grade quality that the recording material has high surface gloss and causes only a slight gloss decrease in the image-recorded area to keep gloss comparable with that in the background area after recording also.
However, the glossiness of ink jet recording paper is generally low in the image-recorded area, compared with in the background area. This phenomenon is supposed to occur with a cause that, simultaneously with the absorption of ink adhering to the recording paper surface, the resin and the pigment contained in the ink-receiving layer of recording paper dissolve or swell in the ink and therefrom the surface structure of the recording paper collapses.
In order to solve these problems, some proposals as mentioned below have so far been offered.
As examples of means to provide excellent image quality, the ink jet recording paper prepared by applying a coating color for surface conversion to a low-sized base paper is disclosed in Japanese Tokkai Sho 52-53012 (the term “Tokkai” as used herein means an “unexamined published patent application”), and the ink jet recording paper prepared by impregnating a paper sheet containing therein urea-formaldehyde resin particles with a water-soluble resin is disclosed in Japanese Tokkai Sho 53-49113. These ink jet recording papers of plain paper type can absorb ink quickly, but have a disadvantage in that the ink dots put thereon are liable to be blurred in their circumferences and suffer from a decrease in dot density.
In addition, the ink jet recording paper having on a support surface a coated layer with high ink absorbency is disclosed in Japanese Tokkai Sho 55-5830, and the case wherein the silica powder is used as a filler in the coated layer is disclosed in Japanese Tokkai Sho 55-51581. These ink jet recording papers of coated paper type have improvements in the size, shape, density and color-tone reproduction of ink dots adhering thereto over those of plain paper type.
As to the ink used for those ink jet recording papers, on the other hand, the water-based ink using water-soluble dyes prevails at present. When the images formed on the recording paper get wet as occasionally happens, therefore, the dyes in the image-recorded area are dissolved again to ooze out to the paper surface; as a result, the value as recorded matter is seriously damaged. In other words, such recording papers have a problem of being poor in water resistance.
In another case where the ink-receiving layer contains a large amount of water-soluble resin, the ink jet recording paper has a defect that the resin swells or dissolves upon contact with water-based ink to lower the gloss in the recorded area (the area brought into contact with the ink) in contrast to the background area.
For the purpose of mitigating those drawbacks, the improvement in water resistance of the recording paper by incorporating porous cationic hydrated aluminum oxide particles into an ink-receiving layer has been proposed in Japanese Tokko Hei 3-24906 (the term “Tokko” as used herein means an “examined patent publication”). This proposal directs its attention to the porosity of cationic hydrated aluminum oxide. More specifically, the liquid substances, such as ink and water, enter into pores and are confined thereto; as a result, it becomes very difficult for the ink to cause the swelling and the dissolution in the ink-receiving layer and thereby the decrease of glossiness in the image-recorded area is checked.
Although the proposal mentioned above enabled the production of ink jet recording paper satisfying the two requirements of ensuring excellent image quality and causing no gloss decrease in the image-recorded area, it cannot ensure for the ink jet recording paper sufficiently high surface gloss after recording.
As means to produce ink jet recording paper having satisfactorily high surface gloss after recording, there are known a method of using a calender wherein ink jet recording paper is passed between a hot steel roll and an elastic roll as the pressure is applied thereto, and a cast coating method wherein the ink-receiving layer in a wet condition is pressed against the specular surface of a hot drum and dried as it is (as disclosed, e.g., in JP-A-6-79967).
To mention in detail, the calendering known as a general art of surface treatment is a method of passing a paper sheet t
Hoshino Mitsuhide
Ito Fumiko
Kuwabara Satoshi
Yabe Norio
Kelly Cynthia H.
Millen White Zelano & Branigan P.C.
Nippon Paper Industries Co. Ltd.
Shewareged B.
LandOfFree
Ink jet recording sheet 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 sheet, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ink jet recording sheet will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2995863