Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
2000-11-09
2003-03-25
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
C347S096000
Reexamination Certificate
active
06536890
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention generally relates to the technology of forming color images excellent in terms of coloring property and color evenness. More particularly, the present invention relates to a liquid composition optimally applicable to image forming processes using an ink-jet recording method as well as to an ink set, an image forming method and an image forming apparatus using such a liquid composition.
2. Related Background Art
With the ink-jet recording method, ink is made to fly and stick to a recording medium such as a sheet of paper for recording. Japanese Patent Publications Nos. 61-59911, 61-59912 and 61-59914 disclose an ink-jet recording method using an electrothermal transducer as ejection energy supply means to provide ink with thermal energy and generate a bubble there so as to make it possible to eject liquid droplets. The disclosed method provides an advantage that it allows the use of a high density multi-orifice recording head so that a high resolution and high definition image can be recorded at high speed.
Meanwhile, ink to be used with the known ink-jet recording method contains water as principal ingredient along with a water-soluble high boiling point solvent such as glycol added thereto for the purpose of preventing ink from drying in the nozzle and clogging the latter. Such ink is short of being positionally fixed satisfactorily on the recording medium and can produce an uneven image probably because of the uneven distribution of the filler and the sizing agent on the surface of the recording medium, which is typically a sheet of paper. On the other hand, there has arisen a strong demand for high quality ink-jet recording comparable to the quality level of silver salt photography. Thus, currently there is a strong technological demand for raising the optical density of images formed by ink-jet recording, broadening the spectrum of color reproducibility of ink-jet recording and improving the color evenness of recorded images.
Under these circumstances, various techniques have been proposed to enhance the stability of ink-jet recording and improve the quality of images formed by ink-jet recording. According to certain techniques proposed for recording medium, a filler and a sizing agent are applied to the surface of the base paper of recording medium. For example, porous micro-particles adapted to adsorb coloring materials are applied to the base paper to form an ink receiving layer of porous micro-particles on it. Coat paper (certain types of coated paper) for ink-jet recording is currently marketed as recording medium realized on the basis of such techniques.
As for techniques concerning recording liquid that is to be ejected on the recording medium in the form of a jet stream, there is one proposed for applying ink and a processing solution chemically sensitive to ink onto the recording medium in such a way that they react with each other on the recording medium. Ink-jet printers that utilizes this technique have also been marketed.
For instance, Japanese Patent Application Laid-Open No. 63-60783 discloses a recording method of causing a liquid composition containing a basic polymer to adhere to a recording medium and subsequently recording an image by using inks containing an anionic dye and Japanese Patent Application Laid-Open No. 63-22681 discloses a recording method of mixing a first liquid composition containing reactive chemical species and a second liquid composition containing compounds that react with the reactive chemical species on a recording medium. Furthermore, Japanese Patent Application Laid-Open No. 63-299971 discloses a recording method of applying a liquid composition containing an organic compound having two or more than two cationic radicals per molecule onto a recording medium and subsequently recording an image by using ink containing an anionic dye and Japanese Patent Application Laid-Open No. 64-9279 discloses a recording method of applying an acidic liquid composition containing succinic acid and subsequently recording an image by using ink containing an anionic dye. Japanese Patent Application Laid-Open No. 64-63185 discloses a recording method of applying a liquid composition that makes dyes insoluble before recording an image by using ink.
Additionally, Japanese Patent Application Laid-Open No. 8-224955 discloses a recording method of using a liquid composition containing a first cationic substance showing a different molecular weight distribution range and ink containing an anionic coloring material and Japanese Patent Application Laid-Open No. 8-72393 discloses a liquid composition containing a cationic substrate and finely divided cellulose with ink. These patent documents suggest that they can produce excellent images in terms of high optical density, printing quality and water-resistance as well as color reproducibility and bleeding. Japanese Patent Application Laid-Open No. 55-150396 proposes a recording method of recording an image on a recording medium by means of a dye ink and subsequently applying a water-proofing agent adapted to form a lake there as means for making the recorded image water-resistant.
On the other hand, there has been recognized a problem called bleeding, which is a phenomenon occurring when a plurality of inks of different colors are applied adjacent to each other onto a recording medium for forming a multi-color image and can blur the image by the mixing of inks with each other at the boundary areas of the image.
To avoid the problem, proposals have been made for accelerating the fixing process of ink on the recording medium (such as recording paper). Japanese Patent Application Laid-Open No. 55-65269 discloses a method of adding a compound for improving the permeability of ink such as a surface active agent to ink and Japanese Patent Application Laid-Open No. 55-66976 discloses the use of ink containing a volatile solvent as principal ingredient. However, while the former method of adding a surface active agent to ink may improve the permeability of ink relative to the recording medium to make the ink advantageous in terms of fixation or bleeding, the coloring materials in the ink can also permeate deep into the recording medium to disadvantageously reduce the optical density and the saturation of the image formed on the recording medium.
SUMMARY OF THE INVENTION
The recording medium obtained by applying a filler and a sizing agent to the surface of base paper (hereinafter referred to as coated paper) has been recognized as a technological achievement for forming high quality images.
It is known that the coloring material applied to the surface of a recording medium generally has to be made to remain in an isolated molecular state without being coagulated on the surface in order to obtain a highly saturated image. The porous micro-particles of coat paper operates to show such a functional feature. However, in order to obtain a satisfactory level of optical density and saturation for the image formed thereon, a thick ink receiving layer has to be formed on the surface of base paper by applying porous micro-particles at an enhanced rate to completely cover the base paper so that, as a result, the texture of the base paper can be lost. To begin with, the inventors of the present invention presumed that such a thick ink receiving layer is needed at the cost of the texture of the base paper because the coloring material is not adsorbed by the porous micro-particles effectively and efficiently.
The following description is based on an assumption of using coat paper having a single ink receiving layer.
FIG. 9
of the accompanying drawings is a schematic cross sectional view of a type of coat paper, showing only a part of the surface thereof. Referring to
FIG. 9
, there are shown base paper
901
and an ink receiving layer
903
. Generally, the ink receiving layer contains porous micro-particles
905
and an adhesive agent
907
for rigidly holding them. As ink is applied to the surface, it permeates to fill the gaps among the porous micro-particl
Endo Makiko
Kato Masao
Kondo Yuji
Kurabayashi Yutaka
Ono Mitsuhiro
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