Stock material or miscellaneous articles – Ink jet stock for printing – Plural ink receptive layers
Reexamination Certificate
1999-02-22
2003-10-14
Schwartz, Pamela R. (Department: 1774)
Stock material or miscellaneous articles
Ink jet stock for printing
Plural ink receptive layers
C428S032180, C428S032340, C428S032370
Reexamination Certificate
active
06632488
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink jet recording material. More particularly, the present invention relates to an ink jet recording material usable for an ink jet recording system, in which aqueous ink images are recorded on recording material, having an excellent ink-absorption and capable of recording ink images having high clarity and precision with an excellent reproducibility.
2. Description of the Related Art
The ink jet recording system using an aqueous ink is advantageous in that the noise of the ink jet recording operation is low, colored images can be easily recorded, and the recording can be effected at a high speed. Therefore, the ink jet recording system is widely utilized in terminal printers, facsimile machines, and plotter machines and for printing account books and slips. Since the conventional woodfree paper sheets and coated paper sheets which are usable for usual printing have a poor ink-absorption, the ink images applied on surfaces of the conventional paper sheets remain in a non-dried condition over a long time, and the wetted ink images stain the printers and the printed sheets, and thus the ink images, per se, are solid. Therefore, conventional woodfree paper sheets and coated paper sheets are not practically useful for the ink jet recording system. To solve the above-mentioned problems, Japanese Unexamined Patent Publication No. 52-53012 discloses a recording paper sheet having a low degree of sizing and Japanese Unexamined Patent Publication No. 53-49,113 discloses a recording sheet produced by preparing a paper sheet from an aqueous paper-forming pulp slurry containing a urea-formaldehyde resin and then impregnating the resultant urea-formaldehyde resin-containing paper sheet with a water-soluble polymer.
Further, various types of ink jet recording sheets having a surface layer coated on a paper sheet substrate and containing inorganic porous pigment particles, for example, amorphous silica particles are disclosed, for example, in Japanese Unexamined Patent Publications No. 55-51,583 and No. 56-148,585, for the purpose of improving the quality of the colored images of the ink and the reproducibility of the colored ink images. Also, Japanese Unexamined Patent Publications No. 58-110,287, No. 59-185,690 and No. 61-141,584 disclose various types of porous pigment particles useful for forming a ink receiving layer capable of receiving thereon ink images having high precision and clarity, which preventing a blotting of the printed ink images.
With popularization of the ink jet recording system, the ink jet recording material is required to have both a satisfactory pencil writing property, as an office recording sheet, and a sufficient aqueous ink recording property. To meet the requirements, Japanese Unexamined Patent Publication No. 4-16,379 discloses to use two types of porous pigment particles different in average radius of pores from each other, together, to form the ink receiving layer.
However, since the recent development of the ink jet printing technology is very significant and the precision of the printer has been enhanced, an ink jet recording material having an image quality similar to the image quality of silver salt photography is required.
To meet with the above-mentioned requirement, it is necessary to make the range of reproducible colors broad. For this purpose, the amount of the inks applied onto the recording material tends to increase. Therefore, the recording material must have an increased ink-receiving capacity and an enhanced resistance to cockling of the recording material due to the increased amount of the applied ink.
When aqueous ink images are recorded on a recording material including a substrate comprising a paper sheet, the recorded material may be cockled or corrugated. This phenomenon is referred to as a cockling phenomenon. When the cockling phenomenon occurs, the distance between the recording material surface and the recording head and the contact angle of the recording head with the recording material surface may locally vary, and thus the intervals between ink droplets applied to the recording material surface and the sizes of the ink droplets become uneven, and the positions of the printed ink dots become inaccurate. Therefore, the resultant print has a decreased degree of precision and accuracy, and the printed ink images have a low quality. In a certain case, the cockled recording material comes into contact with the recording head, the recorded ink images are stained by the recording head, the recording material is broken by the recording head and further the recording head is broken.
The cockling phenomenon is assumed to be generated due to the following reasons.
Namely, when aqueous ink jets are applied to a recording material surface, a water component in the aqueous ink penetrates into the paper sheet substrate, through the ink-receiving layer and is absorbed by the pulp fibers in the paper sheet substrate to cause the pulp fibers to swell. It is well known that when the pulp fibers are swollen with water, the degrees of swelling of the pulp fibers in the longitudinal direction thereof and the transverse direction in a right angle with the longitudinal direction are different from each other to a great extent. When the paper sheet is produced by a paper-forming machine, the pulp fibers are mainly oriented in the flow direction in the paper-forming machine. Therefore, the swelling degree of the paper sheet is much higher in the transverse direction than that in the longitudinal (machine) direction. Namely, the paper sheet is anisotropic in the swelling direction. Also, when the ink jets are applied to the recording sheet surface, the amount of the applied ink is variable in response to the pattern of images. Namely, the amount of the applied ink is small in the images having a low density of color and is large in the images having a high density of color. Therefore, the position in the recording material printed with a high color density image has a high swelling degree of the pulp fibers in the paper sheet substrate. The cockling phenomenon of the recording material is generated due to the anisotropy in the water-swelling property of the paper sheet substrate, the unevenness in the amount of the applied aqueous ink, and the unevenness in the swelling degree of the aqueous ink-applied portions of the recording material. Therefore, in the ink jet recording material having a paper sheet substrate, it is very difficult to solve or reduce the cockling problem.
Japanese Unexamined Patent Publications No. 62-95,285 and No. 3-199,081 disclose methods for removing or reducing the cockling problem on the ink jet recording material. In the method of Japanese Unexamined Patent Publication No. 62-95,285, the coating layer is dried under specifically restricted conditions, for example, by a cast-coating procedure, because when the coated recording material is dried under the usual drying conditions, the ultimate elongation of the recording material wetted with water cannot be controlled to a level of 2.0% or less. Also, the Japanese publication provides a drying procedure in which a paper sheet for a substrate of the recording material is dried under specifically restricted conditions and by, for example, a Yankee drier. Also, Japanese Unexamined Patent Publication No. 3-199,081 discloses a method of producing an ink jet recording material having enhanced resistance to cockling, in which method, to make the difference in the degree of fiber orientation of the pulp fibers between the longitudinal and transverse directions in the paper sheet substrate as small as possible, the ratio in the ultimate elongation of the paper sheet substrate wetted in water in the longitudinal direction (machine direction) to that in the transverse direction is controlled to 1.3 or less. These methods are satisfactory to a certain extent, but are unsatisfactory to provide a ink jet recording material capable of recording ink images with high precision and clarity.
SUMMARY OF THE INVEN
Kawashima Yoshiharu
Kohro Takaaki
Kondo Hiromasa
Okumura Yoshitaka
Arent Fox Kintner & Plotkin & Kahn, PLLC
OJI Paper Co., LTD
Schwartz Pamela R.
LandOfFree
Ink jet recording material does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ink jet recording material, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ink jet recording material will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3138624