Stock material or miscellaneous articles – Ink jet stock for printing
Reexamination Certificate
2001-06-26
2003-12-02
Hess, B. Hamilton (Department: 1774)
Stock material or miscellaneous articles
Ink jet stock for printing
C428S500000, C428S522000
Reexamination Certificate
active
06656544
ABSTRACT:
TECHNICAL FIELD
The present invention relates to recording media, and specifically, relates to recording media for ink jet printers, in which superior effects can be exhibited in the storage of recorded images, in particular, in the prevention of deterioration phenomena in recorded images such as lowering of image clarity, decrease in density, and change in color tone, under high temperature and high humidity.
BACKGROUND ART
The use of ink jet printers is further increasing in recent years because they have characteristics such as vividness of recorded images, quiet operation, ease of coloring, and the like. In order to prevent the nozzle from being blocked due to drying of ink, an ink which is difficult to dry must be used in the ink jet printer. As ink having this property, water-soluble ink which is dissolved or dispersed with binder, dye, solvent, additives, or the like, in water, is generally employed. However, a letter or an image formed on the recording medium by using the water-soluble ink is easily affected by storage conditions for recorded images (temperature, humidity, etc.), and lowering of image clarity, decrease in density, and change in color tone are more easily caused than in printed matter using pigment-type inks or in silver halide photographs.
In recent years, as ink jet printers become less expensive and high vividness and colorfulness of printed images is anticipated, the requirements for storage of recorded images, or the like, are gradually becoming severe. Therefore, completely preventing deterioration of recorded images, which is caused by these image storage conditions, is an essential goal for recording media for ink jet printers.
In view of the present state, prevention of deterioration in recorded images caused by storage conditions of recording media for ink jet printers is being researched. Specifically, many methods in which deterioration of recorded images caused by storage conditions is prevented by adding various mordants to an ink receiving layer, have been proposed. However, the effects obtained by adding these mordants are insufficient, and moreover, a deleterious influence which lowers light resistance of images and which is larger than the effect is caused. Thus, although there is fear that the deleterious influences such as lowering image clarity which is larger than the effect of preventing deterioration of recorded images caused by the storage conditions is caused by adding strong mordants, etc., most of the approaches at present are in research with respect to additives, and there is little research with respect to resin compositions having effects of preventing deterioration of recorded images.
Furthermore, in general recording media for ink jet printers, although research with respect to prevention of deterioration of recorded images under indoor environments has been carried out, research under high temperature and high humidity in consideration of light resistance has not yet been sufficiently carried out, and a recording medium having a satisfactory effect for preventing deterioration of recorded images has not yet been obtained. Therefore, it is an object of the present invention to provide a recording medium for ink jet printers, in which superior effects can be obtained in storage of recorded images, and in particular, in the prevention of deterioration of recorded images, such as lowering of image clarity, decrease in density, and change in color tone, under high temperature and high humidity.
DISCLOSURE OF INVENTION
The present inventors have conducted various research with regard to resin compounds for use in an ink receiving layer, and have found that the deterioration of recorded images, such as lowering of image clarity, decrease in density, and change in color tone, under high temperature and high humidity, are very effectively prevented by using a water soluble acrylic type copolymer synthesized and prepared under specific conditions in the ink receiving layer, and the present invention has thereby been attained.
That is, a recording medium for ink jet printers according to the present invention is characterized in that an ink receiving layer is provided on a base material, and the ink receiving layer contains an acrylic type copolymer in which at least (meth)acrylate having a solubility parameter (&dgr;) of 15.0 to 23.0 MPa
½
is a copolymerizing component.
In addition, it is preferable that the acrylic type copolymer used in an ink receiving layer of a recording medium for ink jet printers according to the present invention be copolymerized (meth)acrylate in which an ester group is a cycloalkyl group. Furthermore, it is more preferable that the acrylic type copolymer be a copolymer consisting of at least four copolymerizing components, (a) component: (meth)acrylate having a solubility parameter (&dgr;) of 15.0 to 23.0 MPa
½
, (b) component: dialkylaminoalkyl (meth)acrylate, (c) component: acrylamide, and (d) component: alkoxy polyethylene glycol (meth)acrylate, and it is most preferable that the acrylic type copolymer be a copolymer consisting of five copolymerizing components in which (e) component: 2-hydroxyalkyl (meth)acrylate is further added.
In the case in which the above ink receiving layer is provided as a multilayer, an ink receiving layer provided on the surface side is given a glossiness in which the specular gloss is 10 or more and is formed as a glossiness adjusting layer. In this way, according to a recording medium for ink jet printers of the present invention which contains the above acrylic type copolymer in the glossiness adjusting layer, the glossiness is improved in comparison with conventional media, and a water repellent effect is obtained without decreasing the absorbability of the ink for ink jet printing. Therefore, the medium does not immediately absorb water even if the medium is wetted by water, and an effect for improving the water resistance of the recording medium can also be obtained.
In the following, preferable embodiments according to the present invention will be explained in detail.
A recording medium for ink jet printers of the present invention is a laminated structure in which an ink receiving layer is provided on a base material by a laminating means such as coating method, and the ink receiving layer may consist of two or more layers. The surfacemost layer in the ink receiving layer may be an ink receiving layer in which the specular gloss is adjusted to a desired glossiness, that is, a glossiness adjusting layer. The glossiness of this layer can be optionally adjusted from non-gloss to high-gloss by a coating method, drying method, composition, etc. In the case in which the ink receiving layer consists of multiple layers, an acrylic type copolymer in the present invention may be contained in at least one ink receiving layer.
As an acrylic type copolymer used in an ink receiving layer in a recording medium for ink jet printers of the present invention, it is necessary to contain a copolymer in which (meth)acrylate having a solubility parameter (&dgr;) of 15.0 to 23.0 MPa
½
is a copolymerizing component. In addition, it is preferable that a water-soluble acrylic copolymer consist of (a) component: (meth)acrylate having a solubility parameter (&dgr;) of 15.0 to 23.0 MPa
½
and at least one copolymerizing component chosen from (b) component: dialkylaminoalkyl (meth)acrylate, (c) component: acrylamide, (d) component: alkoxy polyethylene glycol (meth)acrylate, and (e) component: 2-hydroxyalkyl (meth)acrylate. In the following, materials which constitute a recording medium for ink jet printers of the present invention and a process for producing the medium will be explained.
A. Acrylic Type Copolymer
(1) Copolymerizing Component
The present invention is characterized in that an effect for preventing deterioration of recorded images under high temperature and high humidity is exercised by using (a) component: (meth)acrylate having a solubility parameter (&dgr;) of 15.0 to 23.0 MPa
½
as an essential component. The (a) component in the present
Asai Shigeki
Ishikawa Takayuki
Ishikawa Yukari
Iwamoto Kiyoshi
Kubota Nobuhiro
Arent Fox Kintner & Plotkin & Kahn, PLLC
Hess B. Hamilton
Shewareged B.
Tomoegawa Paper Co., LTD
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