Stock material or miscellaneous articles – Structurally defined web or sheet – Discontinuous or differential coating – impregnation or bond
Reexamination Certificate
1996-04-03
2003-06-10
Schwartz, Pamela R. (Department: 1774)
Stock material or miscellaneous articles
Structurally defined web or sheet
Discontinuous or differential coating, impregnation or bond
Reexamination Certificate
active
06576324
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a printing medium suitable for use in printing with inks. In particular, the present invention relates to a printing medium for ink-jet, which can provide images high in optical density and bright in color tone, scarcely causes beading even when using inks comprising a surfactant to improve their penetrability into printing media, and has excellent ink-absorbing capacity, a production process thereof, and an image-forming process using this medium.
2. Related Background Art
In recent years, an ink-jet recording system, in which minute droplets of an ink are flown by any one of various working principles to apply them to a printing medium such as paper, thereby making a record of images, characters and/or the like, has been quickly spread as a recording apparatus for various images in various applications including information instruments because it has features that printing can be conducted at high speed and with a low noise, color images can be formed with ease, printing patterns are very flexible, and development and fixing process are unnecessary.
Further, it begins to be applied to a field of recording of full-color images because images formed by a multi-color ink-jet system are comparable in quality with multi-color prints by a plate making system and photoprints by a color photographic system, and such printed images can be obtained at lower cost than the usual multi-color prints and photoprints when the number of copies is small.
With the improvement in printability such as speeding up and high definition of printing, and full-coloring of images, printing apparatus and printing methods have been improved, and printing media have also been required to have higher properties. This requirement has offered problems to be solved.
In order to solve such problems, a wide variety of printing media has heretofore been proposed. For example, Japanese Patent Application Laid-Open No. 52-53012 discloses paper for ink-jet, in which a base paper web having a low sizing degree is impregnated with a surface coating. Japanese Patent Application Laid-Open No. 53-49113 discloses paper for ink-jet, in which a sheet containing urea-formalin resin powder therein is impregnated with a water-soluble polymer. Japanese Patent Application Laid-Open No. 55-5830 discloses paper for ink-jet recording, in which a coating layer having good ink absorbency is provided on a surface of a base material. Japanese Patent Application Laid-Open No. 55-51583 discloses that non-crystalline silica is used as a pigment in a coating layer. Japanese Patent Application Laid-Open No. 55-144172 discloses an image-receiving sheet having a coating layer containing a pigment which adsorbs a coloring component in a water-based ink. Japanese Patent Application Laid-Open No. 55-146786 discloses that a coating layer formed of a water-soluble polymer is used.
In U.S. Pat. Nos. 4,879,166 and 5,104,730, and Japanese Patent Application Laid-Open Nos. 1-97678, 2-276670, 5-24335 and 6-297831, there have been proposed recording sheets each having an ink-receiving layer in which an alumina hydrate of a pseudoboehmite structure is used.
However, the ideas described in the above documents only relate to the improvement of properties such as ink absorbency, resolution, optical density, coloring ability, color reproducibility and transparency, and these documents do not describe anything about problems of beading which tends to markedly occur at printed areas on printing media when using inks comprising a surfactant, and means for solving such problems.
The term “beading” as used herein refers to a phenomenon caused by the fact that droplets of inks applied to a printing medium aggregate into larger droplets in the course of absorption and/or the like. It is said that beading readily occurs in particular on media low in ink absorbency or slow in fixing speed of a dye in an ink. This beading phenomenon is visually recognized as color irregularity about the size of a bead.
In a printing medium provided with an ink-receiving layer, beading is observed on the surface of the ink-receiving layer or in the interior of the ink-receiving layer.
There are the following problems in the conventional measures for the beading.
1. Japanese Patent Application Laid-Open Nos. 55-29546 and 6-24123 each disclose recording inks, in which a surfactant is added into the inks in a proportion ranging from several percent to ten-odd percent so as to improve the penetrability of the ink. These inks have an advantage that they can be used in printing on plain paper having a comparably high sizing degree. However, when printing is conducted with these inks on a porous ink-receiving layer comprising, as an principal component, a alumina or silica material, there arises a problem that the absorption of the inks becomes poor, or beading occurs. In particular, in an ink in which the concentration of the surfactant is increased near to a critical micelle concentration so as to enhance its penetrability, the ink components applied tend to aggregate on the ink-receiving layer to cause beading.
2. Japanese Patent Application Laid-Open Nos. 58-110287, 60-137685, 60-245588 and 02-276670 each disclose a printing medium in which the porous structure, such as pore radius distribution and pore volume, of an ink-receiving layer are adjusted to increase its ink-absorbing rate and ink absorption quantity.
Japanese Patent Application Laid-Open Nos. 05-024335 and 06-297831 each disclose a printing medium having an ink-receiving layer composed of pseudoboehmite and a binder, in which the thickness of the ink-receiving layer, a ratio of the pigment to the binder and a coating weight of the receiving layer are adjusted to increase its ink-absorbing rate and ink absorption quantity.
These are based on an idea that the ink-absorbing rate is increased, thereby preventing beading. However, the occurrence of beading also depends upon the fixing quantity and speed of a dye in an ink, so that the occurrence of beading cannot be prevented only by the increase of the ink-absorbing rate. Further, these documents do not describe anything about the measures for beading occurring upon the use of inks containing a surfactant.
3. Japanese Patent Application Laid-Open Nos. 57-173194, 60-046290, 63-151477, 04-115983 and 04-122672 each disclose a printing medium using a resin material having high solvent absorbency, while Japanese Patent Application Laid-Open Nos. 60-171190, 61-132376 and 03-043291 each disclose a printing medium to which a surfactant and the like are added.
These are based on an idea that a material high in ink absorbency or ink-diffusing ability is used to improve the absorption of ink. However, the beading phenomenon is also caused by aggregation of a dye in an ink, so that the occurrence of beading cannot be prevented only by the improvement of the ink absorbency. Further, these documents do not describe anything about the measures for beading occurring upon the use of inks containing a surfactant.
4. Japanese Patent Application Laid-Open No. 55-144172 discloses a printing medium provided with a receiving layer containing a pigment which adsorbs a dye in an ink, Japanese Patent Application Laid-Open No. 60-232990 a printing medium provided with an ink-receiving layer containing cationic aluminum oxide, Japanese Patent Application Laid-Open No. 62-264988 a printing medium containing a material which precipitates a dye in an ink, and Japanese Patent Application Laid-Open No. 01-097678 a printing medium using a substance having an adsorbing capacity of from 20 to 100 mg/g in combination with an ink absorbent.
These are based on an idea that the material high in adsorbing capacity is used to increase the adsorption quantity and adsorption rate of a dye in an ink. The water fastness of images printed is improved. However, since the quantity of the dye to be adsorbed on the ink-receiving layer also depends upon the specific surface area and coating weight of a material from which the receiving layer is
Ito Yoshikuni
Yoshino Hitoshi
LandOfFree
Printing medium does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Printing medium, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Printing medium will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3124159