Incremental printing of symbolic information – Ink jet – Medium and processing means
Reexamination Certificate
2000-08-29
2002-06-25
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Medium and processing means
C347S105000, C428S195100
Reexamination Certificate
active
06409334
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an ink jet printing method. More particularly, this invention relates to an ink jet printing method using an ink jet recording element containing a porous ink receiving layer having interconnecting voids and an ink-permeable polyester substrate.
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 or pigment, and a large amount of solvent. The solvent, or carrier liquid, typically is made up of water, an organic material such as a monohydric alcohol, a polyhydric alcohol or mixtures thereof.
An ink jet recording element typically comprises a support having on at least one surface thereof an ink-receiving or image-forming layer, and includes those intended for reflection viewing, which have an opaque support, and those intended for viewing by transmitted light, which have a transparent support.
While a wide variety of different types of image-recording elements for use with ink jet devices have been proposed heretofore, there are many unsolved problems in the art and many deficiencies in the known products which have limited their commercial usefulness.
It is well known that in order to achieve and maintain photographic-quality images on such an image-recording element, an ink jet recording element must:
Be readily wetted so there is no puddling, i.e., coalescence of adjacent ink dots, which leads to non-uniform density
Exhibit no image bleeding
Exhibit the ability to absorb high concentrations of ink and dry quickly to avoid elements blocking together when stacked against subsequent prints or other surfaces
Exhibit no discontinuities or defects due to interactions between the support and/or layer(s), such as cracking, repellencies, comb lines and the like
Not allow unabsorbed dyes to aggregate at the free surface causing dye crystallization, which results in bloom or bronzing effects in the imaged areas
Have an optimized image fastness to avoid fade from contact with water or radiation by daylight, tungsten light, or fluorescent light
An ink jet recording element that simultaneously provides an almost instantaneous ink dry time and good image quality is desirable. However, given the wide range of ink compositions and ink volumes that a recording element needs to accommodate, these requirements of ink jet recording media are difficult to achieve simultaneously.
Ink jet recording elements are known that employ porous or non-porous single layer or multilayer coatings that act as suitable image receiving layers on one or both sides of a porous or non-porous 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 inkjet 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 good quality, including high optical density and low coalescence, and that can be handled without smearing shortly after printing. Large amounts of ink are often required for printing high quality, photographic-type images.
U.S. Pat. No. 5,354,601 discloses a recording sheet wherein an ink absorbing layer is coated on at least one side of a void-containing polyester film substrate. However, there is a problem with this element in that the voids in the polyester film are not connected to each other. Since there is no pathway for ink to penetrate, the substrate will not contribute to a faster dry time, as will be shown hereafter.
U.S. application Ser. No. 09/472,487 of Laney et al. filed Dec. 27, 1999, entitled, “Permeable Surface Imaging Support”, discloses a permeable support for an imaging element which may have an ink receiving layer on top. However, there is no disclosure in this application that the ink receiving layer may be porous.
It is an object of this invention to provide an ink jet printing method using an ink jet recording element that has a fast ink dry time. It is another object of this invention to provide an ink jet printing method using an ink jet recording element that has good image density.
SUMMARY OF THE INVENTION
These and other objects are achieved in accordance with the invention which comprises an ink jet printing method, comprising the steps of:
A) providing an ink jet printer that is responsive to digital data signals;
B) loading the printer with ink jet recording elements comprising an ink-permeable polyester substrate comprising a base polyester layer and an ink-permeable upper polyester layer, the upper polyester layer comprising a continuous polyester phase having an ink absorbency rate resulting in a dry time of less than about 10 seconds and a total absorbent capacity of at least about 14 cc/m
2
, the substrate having thereon a porous image-receiving layer having interconnecting voids;
C) loading the printer with an ink jet ink composition; and
D) printing on the ink jet recording element using the ink jet ink in response to the digital data signals.
Use of the ink jet printing method of the invention provides a fast ink dry time and good image density.
DETAILED DESCRIPTION OF THE INVENTION
As noted above, the ink-permeable polyester substrate used in the invention contains a base polyester layer and an ink-permeable upper polyester layer. This substrate is described more fully in U.S. application Ser. No. 09/472,487 of Laney et al. filed Dec. 27, 1999, entitled, “Permeable Surface Imaging Support”, the disclosure of which is hereby incorporated by reference.
The substrate used in this invention may be made on readily available polyester film formation machines. The substrate is preferably prepared in one step with the ink-permeable upper polyester layer and the base polyester layer being coextruded, stretched, and integrally connected during formation. The one step formation process leads to low manufacturing cost. The substrate used in this invention has rapid absorption of ink, as well as high absorbent capacity, which allows rapid printing and a short dry time. A 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 substrate employed in this invention has the look and feel of paper, which is desirable to the consumer, has a desirable surface look without pearlescence, presents a smooth desirable image, is weather resistant and resistant to curling under differing humidity conditions, and has high resistance to tearing and deformation.
The base and upper polyester layers of the coextruded substrate have levels of voiding, thickness, and smoothness adjusted to provide optimum ink absorbency, stiffness, and gloss properties. The upper polyester layer contains voids 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 base polyester layer of the substrate provides stiffness to the substrate employed in the invention and provides physical integrity to the upper permeable layer. The thickness of the base polyester layer is chosen so that the total substrate thickness is 50 to 500 &mgr;m depending on the required stiffness of the film. However, the thickness of the upper polyester layer is adjusted to the total absorbent capacity of the ink recording element. A thickness of at least 28.0 &mgr;m is needed to achieve a total absorbency of 14 cc/m
2
.
The ink-permeable upper polyester layer preferably contains voids that are interconnected or open-celled. This type of structure enhances ink absorption rate by enabling capillary action to occur.
As descri
Campbell Bruce C.
Chu Lixin
Laney Thomas M.
Todd Lisa B.
Barlow John
Cole Harold E.
Eastman Kodak Company
Shah Manish S.
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