Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
2001-08-22
2004-08-10
Meier, Stephen D. (Department: 2853)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
C347S101000, C347S105000, C347S095000
Reexamination Certificate
active
06773101
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a pigment ink which gives excellent full-color images, an ink-jet recording system using a recording medium and an ink-jet recording method.
2. Related Background Art
With the advent in recent years of color printers and the development of software for personal computers, which are capable of processing color images, there is an increasing demand for providing higher-definition full-color images. Therefore, developments of high-resolution printing heads, special media for ink-jet, which are high in glossiness, whiteness degree and absorbency, etc. are advancing rapidly. Since an ink-jet printing system is a non-contact printing system, plate-making is not required, and high-speed printing becomes feasible. Therefore, the ink-jet printing system is expected to be used in an increasing number of industrial applications.
Many attempts to use pigments as coloring materials for inks in ink-jet recording have been recently made. The reason is that pigments are the best materials for imparting fastness properties such as water fastness and light fastness in an ink-jet system. Such ink-jet inks using such pigments are disclosed as water-based pigment inks satisfying basic properties such as print quality, ejection stability, shelf stability, resistance to clogging and fixing ability in Japanese Patent Application Laid-Open Nos. 2-255875, 6-99656, 4-57859 and 4-57860.
When it is intended to provide a high-definition full-color image with pigment inks, however, sufficient coloring ability is not achieved when plain paper is used. Therefore, such special media for ink-jet as described above must be selected under the circumstances.
In the industrial applications, base materials having no ink absorbency are often used for ink-jet recording. In such a case, an ink-receiving layer must be coated on such a base material to use it.
However, since most of such ink-receiving layers for ink-jet recording have been developed as special media for ink-jet printers using the conventional dye inks, their suitability for pigment inks is not considered. In glossy media in particular, a highly-absorbable water-soluble resin is often used as a main component for their ink-receiving layers. Such an ink-receiving layer involves a disadvantage that the ink-receiving layer itself has no water resistance, namely, that even when a pigment with good water resistance is used, the pigment runs out together with the ink-receiving layer, since the ink-receiving layer is soluble in water. Further, in an image portion formed with the pigment ink, a problem of rub-off resistance, more specifically, a problem arises that when the image portion is touched or rubbed with a finger, the color of the image is simply faded, or the image is stained. This phenomenon is particularly marked at a mixed-color portion of the color image in which the amount of inks applied is increased.
As a current means for solving such a problem as described above, the whole surface of the recording medium with the color image is subjected to a post-treatment such as a laminating treatment. However, such a treatment is not always satisfactory from the viewpoints of cost, workability and the like, and it is desired that it shall be improved.
Some proposals have been made on ink-jet recording media for pigment inks. For example, Japanese Patent Application Laid-Open No. 9-123593 discloses that ink-jet recording is conducted with pigment inks on a highly-absorbable water-soluble receiving layer provided on a porous layer of alumina hydrate as an ink-jet recording medium for pigment inks. However, water among components of the pigment inks applied is absorbed into the porous layer of alumina hydrate, but pigments themselves are fixed to the water-soluble resin layer which is the uppermost layer. Therefore, such a problem of water fastness as described above remains unsolved after all. Japanese Patent Application Laid-Open No. 10-119422 discloses that ink-jet recording is conducted with pigment inks on a carboxylated SBR resin layer provided on a porous layer containing alumina hydrate or silica. Since the carboxylated SBR resin layer is an ink-receiving layer with good affinity for non-aqueous inks, satisfactory suitability for water-based pigment inks is not to be expected. Japanese Patent Application Laid-Open No. 10-67168 discloses that a porous layer containing silica or alumina is provided on a base material (cellulose paper, synthetic paper or the like) having porosity and ink-jet recording is conducted with pigment inks thereon. However, the structure of the base material is limited to that having porosity in which liquid components in the inks can be absorbed. In addition, image properties when a full-color image, in which the amount of inks applied increases, is recorded, particularly, rub-off resistance at an image portion, and the like-are not known.
In any event, under the circumstances, sufficient investigations have not been made on a pigment ink for ink-jet recording and optimization of an ink-receiving layer in and to which the ink is absorbed and fixed.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an ink-jet recording system and method using pigment inks and a recording medium, by which good coloring ability and ink absorbency are achieved when a high-definition full-color image is formed with pigment inks of plural colors, and moreover an ink-jet color recorded article having improved rub-off resistance and water fastness at an image portion thereof is provided.
The above object can be achieved by the present invention described below.
According to the present invention, there is thus provided an ink-jet recording system which employs an ink-jet recording apparatus comprising a recording-medium-holding part for a recording medium having an ink-receiving layer on a base material and an ink-holding part for a pigment ink to record an image on the ink-receiving layer of the recording medium fed from the recording-medium-holding part using the pigment ink fed from the ink-holding part, wherein
(1) the ink-receiving layer of the recording medium is a porous layer comprising alumina hydrate and a resin binder and has a pore volume ranging from 0.1 to 1.0 ml/g; and
(2) the pigment ink comprises an aqueous medium, a resin and a pigment, the particle diameter of the pigment substantially falls within a range of from 10 to 500 nm, and the proportion of the pigment particles having a particle diameter of 300 to 500 nm is at most 30% based on the total number of particles of the pigment.
According to the present invention, there is also provided an ink-jet recording method comprising conducting ink-jet recording on a recording medium having an ink-receiving layer on a base material using a pigment ink to form an image, wherein
(1) the ink-receiving layer is a porous layer comprising alumina hydrate and a resin binder and has a pore volume ranging from 0.1 to 1.0 ml/g; and
(2) the pigment ink comprises an aqueous medium, a resin and a pigment, the particle diameter of the pigment substantially falls within a range of from 10 to 500 nm, and the proportion of the pigment particles having a particle diameter of 300 to 500 nm is at most 30% based on the total number of particles of the pigment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
(Recording Medium)
As the base material used in the present invention, may be used paper such as suitably sized paper, water leaf paper or resin-coated paper, or a film or sheet of a resin. However, the base material is not particularly limited thereto, As the base material formed from a resin, may be used a transparent film such as a film of polyesters, polystyrene, polyvinyl chloride, polymethyl methacrylate, cellulose acetate, polyethylene or polycarbonate, or an film or sheet opacified by filling of alumina hydrate, titanium white or the like, or by foaming.
In order to improve adhesion to the ink-receiving layer, the surface of the base material may be subjected to a surface treatmen
Kondo Yuji
Tochihara Shin-ichi
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Meier Stephen D.
Shah Manish
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