Stock material or miscellaneous articles – Ink jet stock for printing – Hardened – cured – or cross-linked ink receptive layer
Reexamination Certificate
2002-04-04
2004-07-13
Shewareged, B. (Department: 1774)
Stock material or miscellaneous articles
Ink jet stock for printing
Hardened, cured, or cross-linked ink receptive layer
C428S032280, C428S032300, C428S032330, C428S032340
Reexamination Certificate
active
06761941
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a recording material suitable for inkjet recording with liquid ink such as aqueous ink (containing a colorant of dye or pigment) or oily ink or with solid ink that is solid at room temperature but is melted into liquid for image formation. Precisely, the present invention relates to an inkjet recording sheet having the advantage of good receptivity to ink.
2. Description of the Related Art
With remarkable development of information industries in recent years, various information-processing systems have been developed, and various recording methods and devices suitable for such information systems have been developed and put into practical use.
Among the recording methods for information systems, an inkjet recording method has become much popularized not only in office use but also in home use, since it is applicable to various recording materials and the hardware for it is relatively inexpensive and compact and is not so noisy while driven.
With the increase in image resolution in recent inkjet printers, it has become possible to obtain photographic high-quality images in inkjet recording. On the other hand, the hardware for inkjet recording has also been much developed, and various inkjet recording sheets have been developed.
In general, the necessary properties of inkjet recording sheets are that (1) they can rapidly dry (that is, they can rapidly absorb ink), (2) they can receive suitable and uniform ink dots (with no ink bleeding), (3) the granularity of images recorded on them is good, (4) the circularity of ink dots they have received is good, (5) the color density of images recorded on them is high, (6) the color saturation of images recorded on them is high, (7) after printed, they have good lightfastness and waterproofness, (8) their whiteness is high, (9) their storability is good (that is, they do not yellow even after stored long), (10) they hardly deform and their dimensional stability is good (that is, they curl little), and (11) they well run in hardware. In addition, photographic glossy paper to form photographic high-quality images thereon are further desired to have high glossiness, good surface smoothness and a printing paper feel like silver-salt photographs, in addition to the properties mentioned above.
To improve these properties, an inkjet recording sheet with a porous colorant-receiving layer has been developed and put into practical use. Having a porous structure, the colorant-receiving layer of the inkjet recording sheet can rapidly absorb ink (that is, the sheet rapidly dries), and the sheet is glossy.
However, the porous structure-having inkjet recording sheet is problematic in that the porous colorant-receiving layer thereof may crack and the sheet itself often curls since the colorant-receiving layer shrinks in dry while its porous structure is formed. If the layer cracks, the yield of the recording sheet lowers and the quality thereof worsens; and if the recording sheet curls, it could not well run in printers. On the other hand, when the porosity of the colorant-receiving layer is increased in some degree, the amount of fine inorganic pigment particles such as silica to be in the porous layer inevitably increases relative to the binder therein, and the adhesion of the colorant-receiving layer to the support is thereby lowered. This is another problem with the porous structure-having inkjet recording sheet.
In Japanese Patent Application Laid-Open (JP-A) 6-270531, proposed is an inkjet recording sheet that contains a sol filler of silica sol or alumina sol, an inorganic filler of aluminium hydroxide, clay, talc, calcium carbonate or barium sulfate, or a resin filler of acrylic resin, halogeno-olefin resin or melamine resin. Containing such filler, the ink-receiving layer of the recording sheet is prevented from cracking while it is formed and dried, and its dry surface strength is high. However, the filler used does not still solve the problem of poor ink absorbability and poor glossiness of the sheet.
In JP-A 10-119423 and 10-217601, proposed is an inkjet recording sheet having a colorant-receiving layer formed on its support, in which the layer contains fine inorganic pigment particles and a water-soluble resin and its porosity is high.
Having such a structure, the recording sheet proposed has a good ability to absorb ink and has a good ability to receive ink to form high-resolution images thereon and its glossiness is high, but when it is stored for a long time in a high-temperature and high-humidity atmosphere after processed to have images thereon, the solvent in the colorant-receiving layer thereof diffuses along with dye therein to thereby cause a problem of image bleeding in the sheet. The problem is referred to as “time-dependent image bleeding” in stored color prints.
In JP-A 2001-10211, proposed is an inkjet recording sheet that contains polyvinyl alcohol and a water-soluble plasticizer for polyvinyl alcohol in its ink-receiving layer for the purpose of increasing the print density and the glossiness thereof and improving the ink absorbability and the cracking resistance thereof. In this, the water-soluble plasticizer used is ethylene glycol, diethylene glycol or triethylene glycol, and it worsens the storage stability of the coating liquid for the ink-receiving layer. When the sheet contains urea, it often deposits on the surface of the ink-receiving layer while the recording sheet is stored for a long time.
As in the above, the conventional inkjet recording sheets must be further improved in many aspects of, for example, improving the properties of the sheets, preventing the colorant-receiving layer from shrinking in dry while its porous structure is formed, preventing the layer from cracking, improving the ability of the sheets to smoothly run in printers and increasing the adhesion of the colorant-receiving layer to the support.
Anyhow, at present, no one has succeeded in providing a satisfactory inkjet recording sheet that satisfies all the following requirements: Its colorant-receiving layer is tough, not readily cracking, and has a good ink absorbability to form high-resolution images, or that is, the layer has a good ink absorbability; the images formed are glossy and have good lightfastness and good waterproofness not bleeding even after stored for a long time; the images formed are vivid and have a high density, and they can be stably stored for a long time as they are, or that is, the images have good storage stability; and the colorant-receiving layer of the sheet shrinks little in dry while its porous structure is formed, and it well adheres to the support.
SUMMARY OF THE PRESENT INVENTION
The present invention is to solve the problems in the prior art noted above, and to attain the objects mentioned below.
Specifically, one object of the present invention is to provide an inkjet recording sheet that satisfies the following requirements: Its colorant-receiving layer has good ink absorbability, and does not shrink in dry while the porous structure of the layer is formed; the layer does not crack and the sheet having the layer does not curl, or that is, the productivity of the sheet is high, the quality of the sheet is good, and the ability of the sheet to smoothly run in printers is good; and the colorant-receiving layer well adheres to the support.
Another object of the present invention is to provide an inkjet recording sheet, which is tough, not readily cracking, and has a good ink absorbability to form high-resolution images thereon.
Still another object of the present invention is to provide an inkjet recording sheet which is, after processed to form images thereon, highly resistant to water and glossy with no problem of time-dependent image bleeding, and is highly resistant to light such as sunlight and fluorescent light.
The objects of the present invention are attained as follows.
In, its first aspect, the present invention provides an inkjet recording sheet comprising a support and, on a surface of the support, a colorant-recei
Kobayashi Takashi
Suzuki Katsuyoshi
Fuji Photo Film Co. , Ltd.
Shewareged B.
Sughrue & Mion, PLLC
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