Stock material or miscellaneous articles – Ink jet stock for printing – Particles present in ink receptive layer
Reexamination Certificate
1999-05-25
2003-12-30
Hess, Bruce H. (Department: 1774)
Stock material or miscellaneous articles
Ink jet stock for printing
Particles present in ink receptive layer
C427S152000
Reexamination Certificate
active
06670002
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink jet recording sheet. More particularly, it relates to a high quality ink jet recording sheet which is free from yellowing.
2. Discussion of Background
The ink jet recording system is a system wherein fine droplets of ink are jetted by various operational principles such as a deflection, cavity, thermojetting, bubble jetting, thermal ink jetting, slit jetting or spark jetting system, and deposited on an ink jet recording sheet such as a paper sheet to form a record of images or letters. By virtue of its merits such as high speed, low noise, easiness to produce multi-color images, applicability to a wide variety of recording patterns and unnecessity of development or fixation, it has found a wide range of applications in various recording apparatus for figures including Chinese characters and for color images.
Further, images formed by an ink jet recording system using multi-color inks each containing a coloring material of yellow, magenta, cyan or black contained in a solvent such as water or a hydrophilic solvent, are capable of providing a record which is comparable to multi-color printed images by a printing plate system. Still further, when only a small number of prints are required, the ink jet recording system is inexpensive as compared with the development of silver salt photography, and it is being widely used also in the full color image recording field.
The ink jet recording system has been applied to various uses, as a result of developments in technique in recent years. When the use is limited for the output as a hard copy, it can be roughly classified into (1) one for general use (home use and for hobby), (2) one for office use (office automation) and (3) one for business use (EA and factory automation). Particularly for business use, a high quality hard copy of at least 400 dpi (16 dots/mm) is required, and the ink jet recording system is increasingly used.
Particularly, a high quality hard copy obtainable by the ink jet recording system is important as a substitute for a silver salt photography. In addition to the color reproducibility and gradation of the images, the storage stability of the ink jet recording sheet is an important property required. Here, the storage stability of the ink jet recording sheet may be roughly classified into the storage stability of the printed image portion such as color deterioration, color change or bleeding, and the storage stability of white paper such as color deterioration or color change.
Here, particularly with regard to the storage stability of the image portion, it has been known that when a pigment having a high fastness, as proposed, for example, in JP-A-57-10660, JP-A-57-10661, JP-A-4-234467, JP-A-5-156189, JP-A-5-179183, JP-A-5-202324, JP-A-5-263029, JP-A-5-331397, JP-A-6-122846 or JP-A-6-136311, is used instead of a known aqueous dye, light resistance, ozone resistance and water resistance can be significantly improved.
Further, by using an oil-soluble dye such as a naphthol dye, an azo dye, a metal complex dye, an anthraquinone dye, an quinoimine dye, an indigo dye, a cyanine dye, a quinoline dye, a nitro dye, a nitroso dye, a benzoquinone dye, a carbonium dye, a naphthoquinone dye, a naphthalimide dye, a phthalocyanine dye or a pelinine dye, as proposed in JP-B-7-78187, JP-B-7-78188, JP-B-8-6057, JP-B-8-26259, JP-B-6-247034 or JP-B-6-306319, an ink jet recording sheet having a high image density, an excellent color-forming property, high water resistance and cockle resistance, can be obtained.
As described above, with regard to the storage stability of the printed image portion, it has been recognized to be important to conduct overall studies including improvement in the inks, in addition to the ink jet recording sheet, and the inks have been improved in fact.
On the other hand, with regard to the storage stability of white paper, prevention of yellowing has been mainly studied. The yellowing of white paper is due to light, ozone, NO
X
, heat, humidity or the like, and it may sometimes be caused by a certain antioxidant. Particularly, it has been known that the yellowing of white paper by an antioxidant is caused when a high quality hard copy is put in a file for storage, or when an adhesive tape is put on the surface of the ink-receiving layer. It is important to solve the problem for the ink jet recording system to substitute for a silver salt photography, and various studies for improvement have been made. However, a satisfactory ink jet recording sheet has not been obtained yet.
The ink jet recording sheet is required to provide a high image density and a light and clear color tone, to rapidly absorb inks or to prevent bleeding of inks even when printed dots are overlapped, to prevent too much diffusion of printed dots in the lateral direction, to provide almost round printed dots having smooth edge with no diffusion, and to provide high whiteness. It is possible to achieve such objects by coating a synthetic amorphous silica or a salt thereof, or a mixture thereof, with a binder resin as the case requires, on the surface of a paper sheet, or by packing such a material in a paper sheet, as disclosed in JP-A-57-157786, or by incorporating a porous cationic hydrated aluminum oxide in a paper sheet, as disclosed in JP-A-60-232990, or by incorporating a cationic hydrated aluminum oxide as cationic colloidal particles or a synthetic amorphous silica having a large specific surface area by BET method, in a paper sheet, as disclosed in JP-A-60-204390 or JP-A-2-198889.
However, such ink jet recording sheets are Likely to undergo yellowing as mentioned above. In the case of using a synthetic amorphous silica merely having a large specific surface area, or in the case of using colloidal particles of a hydrated alumina having a pseudo boehmite structure, in order to obtain desired image density or color-forming property, white paper significantly turns yellow.
It is estimated that the yellowing of white paper of the ink jet recording sheet is brought about in such a manner that when said recording sheet is put in a file containing 2,6-di-tert-butyl-4-methylphenol (hereinafter referred to as BHT) for storage, BHT transfers from the file to the ink-receiving layer of the recording sheet. Accordingly, it is considered that when the ink jet recording sheet is contacted with an article containing a phenol antioxidant represented by BHT, the recording sheet undergoes yellowing, which is accelerated by secondary factors such as ozone, NO
X
and SO
X
, in air, temperature and humidity.
The yellowing due to BHT is described, for example, in Polymer Degradation and Stability 50 (1995) 313-317, Textil Praxis International Oktober (1980) 1213-1215, Textil Praxis International Marz (1983) 261-264, Textile Chemist and Colorist April (1983) Vol. 15, No. 4, 52-56 and Text. Progr. 15 (1987) 16, and it has been studied in the filed of fiber and apparel as a problem. It is known that the yellowing due to BHT takes place in such a manner that BHT turns to a compound having a stilbene quinone structure through an oxidation reaction.
JP-A-1-222987 interestingly proposes a method to evaluate the catalyst activity of the porous ink-receiving layer in the ink jet recording sheet when a dye in the ink is decomposed by oxygen, by a spot test using [4,4′-methylene-bis-2,6-(di-tert-butylphenol)] (hereinafter referred to as BHT
2
). The spot test by BHT
2
is on the basis such that when BHT is oxidized to form a stilbene quinone structure, it turns yellow. Correlation between results of the test and the color change in a room of the printed images of the ink jet recording material, has been found.
JP-A-1-222987 further proposes that a preferred mode of a coating layer, i.e. the ink-receiving layer, with little yellowing by the spot test by BHT
2
, is one having a silicon-containing pigment containing a metal selected from the group consisting of Mg, Ca, Zn and Ba in an amount of at least 0.1 wt %, contained in a recording surface, i.e. the i
Sekiguchi Hideki
Urasaki Jun
Uto Tetsuya
Hess Bruce H.
Mitsubishi Paper Mills Limited
LandOfFree
Ink jet recording sheet and method for producing it 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 and method for producing it, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ink jet recording sheet and method for producing it will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3108118