Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Weight per unit area specified
Reexamination Certificate
1999-03-26
2001-01-23
Hess, Bruce H. (Department: 1774)
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Weight per unit area specified
C347S105000, C428S195100, C428S211100, C428S331000, C428S537500
Reexamination Certificate
active
06177188
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a recording medium having a natural texture of kenaf paper with excellent characteristics for images, and an ink jet recording method using the recording medium in which ink droplets fly for recording.
1. Related Background Art
The ink jet recording system is a recording method for images and characters by letting minute ink droplets fly and attach to a recording medium such as paper based on various operation principles. The feature of the system includes high-speed printing, low-noise operation, easy adaptation for multi-color printing, and adaptability for various recording patterns, as well as the absence of image fixation process. Recently, the system has been widely used no only for recording images such as characters in monochrome, but also in recording full-color images. Moreover, not limited its use to business machines, this system is rapidly spreading in various fields, such as industry and art creation.
Various materials are used for the recording medium of the ink jet recording system, including not only ordinary paper made of ordinary wood pulp such as copy paper and bond paper, but also various coated sheets each having an image forming layer on its surface, transparent film formed of synthetic resin for OHP, textile of various fibers and the like. Among these, the amount of plain paper used as a recording medium has been remarkably increasing with recent popularization of personal computers, and office automation.
According to the popularization of the ink jet system, various properties are required for the recording medium, such as rapid ink-absorbency, high ink-absorbing capacity, and improved image density and printing quality on printing, as far as increased water resistance of printed matters. It is especially required for the recording medium to allow the ink jet attached to the recording medium quickly to penetrate into the medium and apparently become dry on the surface. Furthermore, since a water-base ink is usually used in the ink jet system, resulting in poor drying properties, a phenomenon called cockling may occur, i.e., the printed portion may become wavy, especially when paper made of cellulose pulp is used as the recording medium.
To solve these problems, Japanese Patent Application Laid-Open No. 55-51583 discloses that a coat layer of amorphous silica and a high-molecular binder provides the high ink absorbency for water-base ink printing, and is suitable for high-speed printing. Therefore, the application of such a coat layer as an ink-receiving layer for the ink jet recording medium seems to be effective.
Kenaf has been attracting attentions as a pulp material for paper production, a substituent for pulp wood. Kenaf pulp made from kenaf is largely classified in the total trunk pulp obtained by pulping both ligneous and bast portions, the bast pulp obtained by pulping only the bast portion, and the ligneous pulp obtained by pulping only the ligneous portion. The kenaf paper mainly made of the kenaf pulp has a texture like Japanese paper, with such properties as bulkiness, large ink-absorbing capacity, and excellent ink-receptibility.
A paper recording medium such as kenaf having an excellent ink absorbency and a large ink-absorbing capacity has a problem that feathering or printing-through occurs when the ink is applied. Furthermore, the printed portion of recording medium is disadvantageously elongated becoming wavy, i.e., so-called cockling occurs. Thus, the kenaf paper excellent in both ink absorbency and image quality properties has not been obtained yet. If an ink receiving layer is formed on a kenaf paper surface to improve the above-mentioned shortcomings, ink jet recording properties such as the ink absorbency and suitability for high-speed printing can be improved, but there is a problem that the natural texture of kenaf paper is lost, and when an ink receiving surface is white, black ink turns to brown, with poor quality of formed full-color image.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a recording medium provided with an ink receiving layer on kenaf paper as a base paper without deteriorating the texture of kenaf paper, to allow the applied ink to penetrate into the medium quickly to suppress cockling or beading on the printed surface, and to provide a high-quality image with a high clarity without feathering or print-through. An ink jet recording method using the recording medium is also provided.
The present invention provides a recording medium which comprises an ink receiving layer on at least one surface of a base paper containing a kenaf pulp, wherein the ink receiving layer contains a pigment, a coating amount of the ink receiving layer is in the range of 1 to 10 g/m
2
by solid content, and a ratio W/D of the elongation of the sheet in water (W) to the density (D) of the recording medium is in the range of 0.1 to 6.0. There is also provided an ink jet recording method using the recording medium.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Preferred embodiments of the present invention is described in detail.
First, the base paper for use in the present invention is described. The base paper made of kenaf pulp is not especially limited so long as it contains the pulp. Therefore, base paper solely made of the kenaf pulp may be used, or paper made of the kenaf pulp and wood pulp or another type of pulp can be used. Kenaf comprises a ligneous portion and a bast portion, and the ligneous portion is slightly different in properties from the bast portion. A ligneous pulp formed of the ligneous portion contains shorter fibers and a large lignin content, while a bast pulp made from the bast portion contains longer fibers and a small lignin content. When the ligneous and bast portions are pulped together, the pulp has intermediate properties.
In the present invention, any kenaf pulp can be used, preferably a kenaf pulp comprised of the ligneous pulp containing an appropriate amount of bast pulp in accordance with desired properties. Specifically, when a chemical ligneous pulp solely made of the kenaf ligneous portion is used, a resulting base paper is poor in air permeability, thus especially when the recording medium of the present invention is used as an ink jet recording paper, the ink absorbency easily becomes insufficient.
The base paper to be used in the present invention contains the kenaf pulp, but the content of the kenaf pulp is preferably in the range of 10 to 100 wt % in total pulp constituting the base paper, more preferably in the range of 30 to 100 wt % from the viewpoint of kenaf texture in the present invention. When the content of kenaf pulp in the base paper is less than 10 wt %, the kenaf paper undesirably lacks the texture or color shade specific to kenaf.
Examples of a pulp which can be used together with the kenaf pulp include wood pulps mainly made from Japanese red pine, black pine, silver fir, todomatsu (
Abies sachalinensis
FR. SCHMIDT), cedar or another coniferous tree, or beech, birch, pasania and another broad-leaved tree. The wood may be pulped in any method and, for example, mechanical pulp, sulfite pulp, kraft pulp, semi-chemical pulp, chemimechanical pulp, refiner ground wood pulp and the like can be used. Wastepaper pulp obtained by recycling can further be used. Moreover, in the recording medium of the present invention, in addition to the cellulose fibers, glass fiber or another inorganic fiber, or polyester fiber, aramid fiber or another synthetic fiber may appropriately be used as required. To produce the base paper used in the present invention, the above-mentioned materials may be used together with the kenaf pulp, alone or in appropriate combination thereof according to the use of the recording medium.
The base paper used in the present invention can be made using a conventional paper machine after adding to the pulp materials containing the kenaf pulp those additives including: various fillers for improving paper softness, surface smoothness, opacity, printing capa
Ichioka Masako
Kondo Yuji
Yoshino Hitoshi
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Hess Bruce H.
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