Stock material or miscellaneous articles – Ink jet stock for printing – Physical property of ink receptive layer specified
Reexamination Certificate
2001-11-28
2004-05-18
Shewareged, B. (Department: 1774)
Stock material or miscellaneous articles
Ink jet stock for printing
Physical property of ink receptive layer specified
C428S032350, C428S032380
Reexamination Certificate
active
06737128
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an ink-jet recording sheet (hereinafter referred simply to as a recording sheet), and in more detail to an ink-jet recording sheet which exhibits excellent ink absorbance and results in minimized image degradation due to harmful gases. Further, the present invention relates to an ink-jet recording method in which recording is carried out by jetting ink and a preparing method of the recording material.
BACKGROUND OF THE INVENTION
Ink-jet recording is carried out in such a manner that fine ink droplets are jetted onto a recording sheet such as a paper sheet, employing various working principles so that images and text are recorded. Said ink-jet recording exhibits advantages such as relatively high speed, low noise, and easy multicolor reproduction.
Conventional drawbacks with nozzle clogging and maintenance in said recording method have been overcome due to improvement of both inks and devices. As a result, at present, said recording method has been increasingly applied to various fields such as various types of printers, facsimile machines, and computer terminals.
Recently, said printers have been particularly improved so as to produce high quality images which approach conventional photographic image quality. Accordingly, needed are recording sheets capable of realizing conventional photographic quality and of further reproducing conventional photographic print-like properties (glossiness, smoothness and toughness).
In order to reproduce such conventional photographic print-like properties, developed as conventional recording sheets have been so-called swelling type sheets which are prepared by applying hydrophilic binders such as gelatin and polyvinyl alcohol onto a support. However, said sheets exhibit drawbacks such as slow ink absorption, surface stickiness after printing, and ease of image bleeding due to the presence of moisture during storage. Particularly, it is very difficult to reach the conventional photographic image quality due to the fact that since the ink absorption rate is low, prior to ink absorption, ink droplets are blended with each other, tending to result in bleeding between different colors and beading within the same colors.
Instead of said swelling type recording sheets, a so-called porous type recording sheet has now been playing a major role. Said porous type recording sheet exhibits a feature in that since ink is absorbed into multiple fine voids, the ink absorption rate is high. Examples of recording sheets, which achieve conventional photographic image quality, as well as conventional photographic print-like properties, as described above, are described in Japanese Patent Publication Open to Public Inspection Nos. 10-119423, 10-119424, 10-175364, 10-193776, 10-193776, 10-217601, 11-20300, 11-106694, 11-321079, 11-348410, 10-178126, 11-348409, 2000-27093, 2000-94830, 2000-158807, and 2000-211241.
On the other hand, in addition to said image quality and conventional-print like properties, higher level of durability as well as image retention properties has been demanded and much researches has been conducted to improve light fastness, moisture resistance, and water resistance to the level of silver halide photography. For example, regarding improvement of the light fastness, many techniques are disclosed in Japanese Patent Publication Open to Public Inspection Nos. 57-74192, 57-87989, 57-74193, 58-152072, 64-36479, 1-95091, 1-115677, 3-13376, 4-7189, 7-195824, 8-25796, 11-321090, 11-277893, 2000-37951.
In addition to the light fastness problem, porous type recording sheets have a problem in which, due to the multiple-void structure, discoloration and fading tend to occur due to harmful gases. Water-soluble phthalocyanine based dyes, which are employed in common color ink-jet printers, tend to result in said problem.
The mechanism of said discoloration and fading has not yet been fully clarified. However, it is assumed that a very small amount of active harmful gases such as ozone, oxidants, SO
x
, and NO
x
in ambient air decomposes said dyes, since the multiple-void structure has a large surface area and an active surface of inorganic fine particles.
Techniques for reducing said discoloration and fading are described in Japanese Patent Publication Open to Public Inspection Nos. 63-252780, 64-11877, 1-108083, 1-216881, 1-218882, 1-258980, 2-188287, 7-237348, 7-266689, 8-164664, and others. However, recording sheets for producing photographic image quality, utilizing a finer multiple-void structure than conventional, tend to be more readily degraded. Accordingly, conventional improvement techniques have not resulted in sufficient effects and more essential improvement has been demanded.
Said swelling type recording sheets tend to result in fewer such problems, but exhibit inherent difficulty to improve the low ink absorption rate.
It is possible to overcome discoloration and fading problems by utilizing an ink-jet recording method in which a pigment-based ink is used. However, drawbacks such as bronzing on the recording sheet surface have not been overcome so as to result in sufficiently acceptable image quality in terms of overall product quality. Further, the following gas insulation methods are very effective: prints are subjected to a lamination treatment or placed in a frame, or as described in Japanese Patent Publication Open to Public Inspection Nos. 53-27426, 59-222381, 62-271781, 11-157207, 11-245507, and 2000-71608, recording sheets, comprising fine thermoplastic particles on the surface, are printed, and subsequently heated or pressed to result in formation of a gas insulation layer. However, each of said methods needs a post-treatment to result in an additional manufacturing process. Specifically, in ink-jet recording employing a large-sized sheet at a width of at least 60 cm, lamination and heat roll treatments are troublesome and special devises are expensive. Accordingly, it can be safely assumed that said methods are not generally employed.
Japanese Patent Publication Open to Public Inspection No. 63-60784 describes an ink-jet recording media comprising a porous layer having organic fine particles and inorganic fine particles. However, the organic fine particles disclosed in the Japanese Publication are only capable of being dissolved in a special solvent having high solubility, and cannot dissolved in organic solvents, which are used in conventional inks for ink-jet recording. Therefore, such ink-jet recording medias cannot be used in conventional ink-jet recording.
From the viewpoints of the foregoing, the present invention has been achieved. An object of the present invention is to minimize image degradation due to harmful gases without applying any additional process to an ink-jet recording sheet having a high ink absorption rate.
SUMMARY OF THE INVENTION
The object of the present invention has been achieved employing the following embodiments.
[Structure 1]
An ink-jet recording sheet comprising a first porous layer at the outermost position of the ink-jet recording sheet, wherein the ink-jet recording sheet satisfies the following Formula (1), when an aqueous solution, which comprises a water-soluble alcohol-type organic solvent having an SP value in an range of from 18.414 to 30.69 (MPa)
½
and a boiling point of not less than 120° C. in an amount of from 10 to 40%, is provided to the surface of the ink-jet recording sheet in an amount of 20 ml/m
2
,
Vc/Vd≦
0.4 Formula (1)
wherein Vc represents a water transition amount of a first area of the ink-jet recording sheet, where the aqueous solution is provided, during a contact time of 0.8 seconds when the first area is subjected to Bristow's Measurement, and Vd represents a water transition amount of a second area of the ink-jet recording sheet, where the aqueous solution is not provided, during a contact time of 0.8 seconds when the second area is subjected to Bristow's Measurement.
[Structure 2]
The ink-jet recording sheet of Structure 1, wherein the ink-jet recording shee
Konica Corporation
Muserlian Lucas and Mercanti
Shewareged B.
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