Stock material or miscellaneous articles – Structurally defined web or sheet – Discontinuous or differential coating – impregnation or bond
Reexamination Certificate
1999-12-27
2002-04-30
Hess, Bruce H. (Department: 1774)
Stock material or miscellaneous articles
Structurally defined web or sheet
Discontinuous or differential coating, impregnation or bond
C428S212000, C428S304400, C428S480000
Reexamination Certificate
active
06379780
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to an opaque image-recording element and, more particularly, the present invention relates to a recording element for an automated printing assembly such as a computer-driven ink-jet printer having excellent ink-receiving properties.
BACKGROUND OF THE INVENTION
In a typical ink-jet recording or printing system, ink droplets are ejected from a nozzle at high speed towards a recording element or medium to produce an image on the medium. The ink droplets, or recording liquid, generally comprise a recording agent, such as a dye, and a large amount of solvent in order to prevent clogging of the nozzle. The solvent, or carrier liquid, typically is made up of water, an organic material such as a monohydric alcohol or a polyhydric alcohol or a mixed solvent of water and other water miscible solvents such as a monohydric alcohol or a polyhydric alcohol.
The recording elements or media typically comprise a substrate or a support material having on at least one surface thereof an ink-receiving or image-forming layer. The elements include those intended for reflection viewing, which usually have an opaque support, and those intended for viewing by transmitted light, which usually have a transparent support.
While a wide variety of different types of image-recording elements have been proposed heretofore, there are many unsolved problems in the art and many deficiencies in the known products which have severely limited their commercial usefulness. The requirements for an image-recording medium or element for ink-jet recording are very demanding. For example, the recording element must be capable of absorbing or receiving large amounts of ink applied to the image-forming surface of the element as rapidly as possible in order to produce recorded images having high optical density and good color gamut.
One example of an opaque image-recording element is described in U.S. Pat. No. 5,326,391. It consists of a layer of a microporous material which comprises a matrix consisting essentially of a substantially water-insoluble thermoplastic organic polymer, such as a linear ultra-high molecular weight polyethylene, a large proportion of finely divided water-insoluble filler of which at least about 50 percent by weight is siliceous and interconnecting pores. The porous nature of the image-recording element disclosed in U.S. Pat. No. 5,326,391 allows inks to penetrate the surface of the element to produce text and/or graphic images. However, the cost of producing these elements is relatively high. Also, the image density has been found to be of poor quality, i.e., the images have low optical densities and poor color gamut. U.S. Pat. No. 5,605,750 has already addressed the latter shortcomings of image density and color gamut via the application of an upper image-forming layer. This upper image forming layer is a porous, pseudo-boehmite having average pore radius of from 10 to 80 Å. However, the high manufacturing cost of the article to form the absorbent layer is not solved in U.S. Pat. No. 5,605,750. This is due to the requirements for the porous substrate as described in U.S. Pat. No. 5,326,391. Thus, it can be seen that a need still exists in the art for the provision of an opaque image-recording element suitable for use in an ink-jet printer, which is capable of recording images (including color images) having fast dry times, high optical densities and good color gamut, but which is capable of being manufactured at a relatively low manufacturing cost. It is towards fulfilling this need that the present invention is directed.
PROBLEM TO BE SOLVED BY THE INVENTION
There remains a need for an image-receiving member that has rapid absorption of ink and relatively low cost.
SUMMARY OF THE INVENTION
It is an object of the invention to overcome disadvantages of prior imaging supports.
It is another object of the invention to produce imaging supports that have short dry time for inks.
It is a further object of the invention to provide imaging supports that are dimensionally stable and low in cost.
These and other objects of the invention are accomplished by an imaging support comprising a base polyester layer and an ink permeable upper layer, said upper layer comprising of a continuous polyester phase having an ink absorbency rate resulting in a dry time of less than 10 seconds and a total absorbent capacity of at least 14.0 cm
3
/m
2
.
ADVANTAGEOUS EFFECT OF THE INVENTION
It is an object of the invention to provide an imaging member that has a high absorptive capacity for ink and is relatively low in cost.
DETAILED DESCRIPTION OF THE INVENTION
The invention has numerous advantages over prior practices in the art. The imaging members of the invention may be made on readily available polyester film formation machines. The members of the invention preferably are made in one step with the permeable layer and the bottom base layer being coextruded, stretched, and integrally connected during formation. The imaging members are low in cost as the one step formation process leads to low manufacturing cost. The imaging members of the invention have rapid absorption of ink, as well as high absorbent capacity, which allows rapid printing and short dry time. Short dry time is advantageous, as the prints are less likely to smudge and have higher image quality as the inks do not coalesce prior to drying. The imaging members of the invention have the look and feel of paper, which is desirable to the consumer. The imaging members of the invention have a desirable surface look without pearlescence and present a smooth desirable image. The imaging member of the invention further is weather resistant and resistant to curling under differing humidity conditions. The imaging members of the invention further have high resistance to tearing and deformation. These and other advantages will be apparent from the detailed description below.
The term as used herein, “top”, means the side or toward the side of the permeable polyester layer. The terms “bottom” and “base” mean the side or toward the side of the base polyester.
The layers of the coextruded polyester sheet of this invention have levels of voiding, thickness, and smoothness adjusted to provide optimum ink absorbency, stiffness, and gloss properties. The polyester sheet has a voided layer to efficiently absorb the printed inks commonly applied to ink-jet imaging supports without the need of multiple processing steps and multiple coated layers. The coextruded polyester base of the invention contains a polyester layer to provide stiffness to the imaging support of the invention and to provide physical integrity to the highly voided absorbing layer. The thickness of the base layer is chosen to cause the total imaging support thickness to be 50 to 500 &mgr;m depending on the required stiffness of the film. However, the thickness of the top layer is adjusted to the total absorbent capacity of the medium. A thickness of at least 28.0 &mgr;m is needed to achieve a total absorbency of 14 cm
3
/m
2
. The rate at which inks are absorbed into the permeable layer is critical as discussed hereinbefore. The voiding should be such that the voids are interconnected or open-celled. This type of structure enhances ink absorption rate by enabling capillary action to occur. The sheet of the described invention has a permeable layer with an absorbing rate resulting in a dry time of less than 10 seconds.
Dry time is measured by printing a color line on the side of the top layer with an ink-jet printer at a laydown of approximately 15 cm
3
/m
2
utilizing inks of the following formulation:
2-Pyrro-
Diethylene
1,5
Ink
Water
lidone
Glycol
Pentadiol
EHMP
Dyes
Cyan
76%
6%
ND
8.6%
7.7%
1.7%
Magenta
75%
7.8%
ND
8.5%
7.5%
1.2%
Yellow
81%
4.2%
4.3%
ND
8.2%
1.3%
Where: EHMP=2-ethyl-2-(hydroxymethyl)-1,3-propanediol
This was accomplished utilizing an HP 722 ink-jet printer using standard HP dye-based ink cartridge (HP #C1823A) with the printed lines running in the direction of the sheet as it is conveyed through
Arrington Eric E.
Greener Jehuda
Laney Thomas M.
Sampson Julie A.
Eastman Kodak Company
Hess Bruce H.
Leipold Paul A.
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