Paper making and fiber liberation – Processes and products – Non-fiber additive
Reexamination Certificate
2001-10-05
2003-09-09
Fortuna, Jose A. (Department: 1731)
Paper making and fiber liberation
Processes and products
Non-fiber additive
C162S158000, C428S326000, C428S323000
Reexamination Certificate
active
06616808
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to an inkjet printing paper of noncoated type. More particularly, the invention relates to an inkjet printing paper of noncoated type, which is produced from 100% of waste paper pulp through a paper machine.
BACKGROUND OF THE INVENTION
An inkjet printer is a unit for printing images, letters, various graphics and the like, by an inkjet printing method where small drops of ink are ejected directly against a printing paper for the attachment of the ink according to various operation principles represented by piezoelectric type, thermal type.
The inkjet printer has many advantages. This unit can be operated in high speed and quietly. With the inkjet printer, it is easy to perform multiple color printing. Further, this unit has flexibility in use of printing patterns. Additionally, the inkjet printer requires neither development nor fixing. The inkjet printer can offer images of multiple color with inks of various colors. These colors contain color materials, such as yellow, magenta, cyanogen, black, which are dissolved in solvents. Then, the inkjet printer yield images which are not less fine and not less clear than those obtained from a printing method of photoengraving or plate making. In these years, due to such advantages, the inkjet printers have quickly come into wide use.
The printing paper used for the inkjet printer is required to have the following properties. The paper of this kind should have high opacity, printing density, and white degree. Further, this paper is needed to perform vibrant coloring and absorb ink quickly. Then, on the inkjet printing paper, it is desired that ink does not run even when ink-dots are overlapped each other. It is also desired that the size of each ink-dot is controlled so as not to exceed its suitable one. Additionally, the inkjet printing papers are to be fed in an inkjet printer without any trouble such as paper jam. That is to say, the inkjet printing paper should have reliable conveyability.
Inkjet printing papers can be divided into two types, coated type and noncoated type. In order to produce each coated paper, on the surface of a pure paper, synthetic paper, synthetic resin film, or the like, a coating mixture, mainly containing filler and binder, is coated by utilizing a coater such as a blade coater and knife coater. Therefore, an ink recepter layer is formed on the coated paper. The noncoated paper is typically a pure paper and wood containing paper. The inkjet printing paper of noncoated type can be used more widely, comparing with coated type. The noncoated paper can be used for not only inkjet printers but also other kinds of printers and usual writing materials. Further, the inkjet printing paper of noncoated type has an advantage to be economical, since waste papers can be used as the material pulp. In contrast to this, the waste papers can not be used for the inkjet printing paper of coated type.
However, as for the above inkjet printing properties, a current noncoated inkjet printing paper is inferior to the coated one. Particularly when the noncoated paper is produced from the waste papers, a certain amount of waste paper pulp, which is contained in the noncoated paper, deteriorates fibers in the paper. Accordingly, the above inkjet printing properties can not be supported in the noncoated paper.
The noncoated inkjet printing paper does not have an ink recepter layer. This means that the fibers formed on the surface of the noncoated inkjet printing paper are exposed so that the paper tends to be blotted with the ink. This phenomenon is called as feathering. One drawback of the current noncoated inkjet printing paper is high tendency of this feathering. In order to prevent this phenomenon, it has been considered to increase the amount of filler for improving the smoothness of the paper. However, too many filler increases the tendency of paper powders to fall from the paper's surface. At the same time, the smoothness of the paper results in decrease of its conveyability. As a result, feathering can not be restrained effectively only by increasing the amount of filler.
SUMMARY OF THE INVENTION
It is, therefore, the first object of the present invention is to provide an inkjet printing paper of noncoated type, where inkjet printing properties are satisfied, feathering can be restrained sufficiently, and reliable conveyability is ensured. The second object of the present invention is to provide an inkjet printing paper of noncoated type, which can be produced from recycled waste papers in order to utilize resources effectively. The third object of the present invention is to provide a printing method, which allows inkjet printing paper of noncoated type to be printed without feathering and to provide a printed matter, which is obtained from such method.
According to the first aspect of the present invention, there is provided an inkjet printing paper of noncoated type produced from pulp through a paper machine, the paper comprising filler, which has calcium carbonate, wherein the paper contains ash of 10 to 30 weight % as defined in JIS P 8128 and wherein the paper has Stockigt sizing degree of 0.001 to 0.05 sec/g/m
2
according to JIS P 8122.
In the first aspect of the present invention, this inkjet printing paper comprises the filler, which has calcium carbonate, and the paper contains ash of 0 to 30 weight % as defined in JIS P 8128. By doing so, the above mentioned feathering can be prevented. Additionally, this inkjet printing paper has Stockigt sizing degree of 0.001 to 0.05 sec/g/m
2
according to JIS P 8122. This makes the paper to absorb ink very quickly whereby the ink can be dried easily on the paper. This results in that the size of each ink-dot is controlled so as not to exceed its suitable size and the ink-dots are prevented from overlapping. Accordingly, the ink does not run on this inkjet printing paper. Precisely, the preferable inkjet printing properties are given to the inkjet printing paper, which ensures clear inkjet printing. As used herein the term “Stockigt sizing degree according to JIS P 8122” refers to the value of (Stockigt sizing degree according to JIS P 8122)/(basis weight).
According to the second aspect of the present invention, there is provided an inkjet printing paper of noncoated type produced from pulp through a paper machine, the paper comprising filler, which has calcium carbonate, wherein, on X-ray image obtained from area-analysis with an energy-distributed X-ray microanalyzer for the surface of the inkjet printing paper, area of white part, which indicates the presence of calcium, is 3 to 40% related to the total area of the X-ray image.
In the second aspect of the present invention, the inkjet printing paper is produced so that on the X-ray image obtained from the area-analysis with the energy-distributed X-ray microanalyzer for the surface of the inkjet printing paper, the area of white part, which indicates the presence of calcium, is 3 to 40% related to the total area of the X-ray image. This makes the paper to absorb ink very quickly, whereby the ink can be dried easily on the paper. This results in that the size of each ink-dot is controlled so as not to exceed its suitable size and the ink-dots are prevented from overlapping. Accordingly, the ink does not run on this inkjet printing paper. Precisely, the preferable inkjet printing properties are given to the inkjet printing paper, which ensures clear inkjet printing.
The above mentioned pulp can be made from 100% of waste paper pulp. By recycling the waste papers, resources can be utilized effectively, which leads to environmental protection.
At least one side of the front and back sides of the inkjet printing paper may have the coefficient of dynamic friction of 0.3 to 0.7 measured according to JIS P 8147.
Since the inkjet printing paper has the coefficient of dynamic friction of 0.3 to 0.7, reliable conveyability can be ensured, resulting in the prevention of paper jam. In addition, by using such inkjet printing paper, a feed roller can be kept free from paper powders.
The
Ando Hiroyuki
Haga Katsuhiko
Osumi Hiroyuki
Yamada Noboru
Fortuna Jos'e A.
McDermott & Will & Emery
Seiko Epson Corporation
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