Incremental printing of symbolic information – Ink jet – Medium and processing means
Reexamination Certificate
2000-11-09
2002-10-08
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Medium and processing means
C347S100000, C347S096000
Reexamination Certificate
active
06460989
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a technique for forming a color image with excellent color development and color uniformity Particularly, the present invention relates to an ink set comprising a liquid composition and an aqueous color ink suitable for image formation by an ink-jet recording system, a method for forming a colored area on a recording medium; and an ink-jet recording apparatus employing the ink set.
2. Related Background Art
The ink-jet recording system conducts recording by ejecting an ink onto a recording medium like a paper sheet. For example, ink-jet recording systems which employ an electro-thermal transducer as an ejection energy supplying means and eject liquid droplets by forming bubbles in the ink with thermal energy applied to the ink are disclosed in Japanese Patent Publication Nos. 61-59911, 61-59912, and 61-59914. In such an ink-jet recording system, the recording head orifice can readily be multiplied in a high density to obtain images with high resolution and high quality at a high speed.
In conventional ink-jet recording systems, the ink is mainly composed of water and contains a water-soluble high-boiling solvent such as glycol to prevent drying of ink in the nozzle and clogging of the nozzle, and for other purposes. Such an ink may cause problems of incomplete fixation of the ink, or nonuniformity of the formed image presumably caused by nonuniform distribution of a filler or a sizing agent on the face of a recording medium paper sheet. On the other hand, in recent years, the ink-jet recorded image is required to have a high image quality comparable to that of silver salt photograph and greatly demanded technically to give a higher image density and a broader color reproduction range of the ink-jet recorded image, and higher uniformity of the color of the recorded image
In such circumstances, many methods are proposed for stabilization of the ink-jet recording and improvement of the quality of ink-jet recorded matters One of the proposals concerning the recording medium is a method of coating the base paper of the recording medium with a filler or a sizing agent on the surface thereof. For example, porous fine particles capable of adsorbing a coloring material are applied as a filler on the base paper to form an ink-receiving layer. Coated paper for ink-jet recording is commercially available as the recording medium produced by employing such techniques.
Other typical methods are summarized below.
(1) Incorporation of a Volatile Solvent, or a Penetrative Solvent Into an Ink:
Japanese Patent Application Laid-Open No. 55-65269 discloses adding a compound which promotes penetration of a surfactant or the like to the ink for accelerating fixation of the ink on the recording medium. Japanese Patent Application Laid-Open No. 55-66976 discloses using an ink mainly composed of a volatile solvent
(2) Mixing of an Ink with a Liquid Composition Reactive to the Ink on a Recording Medium.
An image-improving liquid composition is applied on a recording medium, before or after application of a recording ink, to improve image density and water resistance and to prevent bleeding.
Japanese Patent Application Laid-Open No. 63-60783 discloses preliminary application of a basic polymer-containing liquid composition and subsequent recording with an ink containing an anionic dye. Japanese Patent Application Laid-Open No. 63-22681 discloses a recording method in which a first liquid composition containing a reactive chemical species and a second liquid composition containing a compound capable of reacting with the reactive chemical species are mixed on a recording medium. Japanese Patent Application Laid-Open No. 63-299971 discloses preliminary application of a liquid composition containing an organic compound having two or more cationic groups per molecule onto a recording medium and subsequent recording with an ink containing an anionic dye. Japanese Patent Application Laid-Open No. 64-9279 discloses a recording method in which an acidic liquid composition containing succinic acid or the like is applied onto a recording medium and subsequently recording is conducted with an ink containing an anionic dye.
Japanese Patent Application Laid-Open No. 64-63185 discloses application of a liquid composition capable of insolubilizing an ink dye before recording with an ink. Japanese Patent Application Laid-Open No. 8-224955 discloses using a liquid composition containing cationic substances of different molecular distribution regions in combination with an ink containing an anionic compound. Japanese Patent Application Laid-Open No. 8-72393 discloses using a liquid composition containing a cationic substance and finely pulverized cellulose in combination with an ink. These methods are said to give good images which are high in the image density, better in the print quality and water resistance, and also better in the color reproducibility and non-bleeding. Japanese Patent Application Laid-Open No. 55-150396 discloses, after recording with a dye ink on a recording medium, applying a water resistance-imparting agent which forms a lake by reaction with the dye to improve the water resistance of a recorded image.
(3) Mixing of an Ink with a Fine Particle-containing Liquid Composition on a Recording Medium:
Japanese Patent Application Laid-Open No. 4-259590 discloses applying a colorless liquid containing colorless inorganic fine particles on a recording medium and subsequently applying a nonaqueous recording liquid thereto. Japanese Patent Application Laid-Open No. 6-92010 discloses a method in which a solution containing fine particles or a solution containing fine particles and a binder polymer is first applied to a recording medium and subsequently an ink containing a pigment, a water-soluble resin, a water-soluble solvent and water is applied thereto. These methods are said to give images with better print quality and color development, irrespective of the kind of paper used.
Background Technique
The inventors of the present invention, after comprehensive investigation on various ink-jet recording techniques as mentioned above, have found that the above described methods achieve remarkable effects in solving the respective technical problems, but other important ink-jet recording properties may be impaired instead. For example, the above technique (1) improves fixation of an ink on a recording medium, but the Image density may become deteriorated, and the color reproduction range which is important in recording on plain paper or recording a color image may become insufficient. The above technique (2) gives high image density owing to the coloring material of the ink made to remain on the surface of a recording medium, but the color reproduction range or color chroma may be lowered, presumably owing to aggregation of the coloring material on the surface of the recording medium.
The aforementioned recording medium having a base paper the surface of which is coated with a filler or a sizing agent (hereinafter referred to as “coated paper”) is recognized to be capable of forming a high-quality image.
Generally, for obtaining an image of high chroma, it is known that the coloring material should be left on the surface of a recording medium in a monomolecular state without being aggregated. The fine porous particles of the coated paper serve surely to make the coloring material to remain on the recording medium surface. However, for achieving a high image density and high image chroma, a larger amount of the porous fine particles is required to form an ink-receiving layer with a thickness enough to cover the base paper, which gives rise to a disadvantageous problem that the feel or texture of the base paper sheet is lost. The inventors have presumed that such a thick ink-receiving layer is required because the coloring material is not effectively adsorbed to the porous fine particles.
For the explanation below, a coated paper is taken which has a single ink-receiving layer.
FIG. 9
shows schematically a cross section of the s
Endo Makiko
Kato Masao
Kondo Yuji
Kurabayashi Yutaka
Ono Mitsuhiro
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