EP1288011A2

EP1288011A2 - Ink jet recording element and printing method

Info

Publication number: EP1288011A2
Application number: EP02078431A
Authority: EP
Inventors: Sridhar Eastman Kodak Company Sadasivan; Lixin Eastman Kodak Company Chu; John Marion Eastman Kodak Company Baier; Elizabeth Ann Eastman Kodak Company Gallo
Original assignee: Eastman Kodak Co
Current assignee: Eastman Kodak Co
Priority date: 2001-08-31
Filing date: 2002-08-19
Publication date: 2003-03-05
Anticipated expiration: 2022-08-19
Also published as: EP1288011A3; JP4149765B2; DE60209997D1; EP1288011B1; JP2003145927A; DE60209997T2

Abstract

An ink jet recording element comprising a support having thereon a porous image-receiving layer comprising at least 50% by weight of particles and less than 20% by weight of a binder, the particles comprising a mixture of (a) inorganic particles having a primary particle size of from 7 to 40 nm in diameter which may be aggregated to provide a mean aggregate particle size of up to 500 nm; and (b) colloidal particles having a mean particle size of from 20 to 500 nm; and wherein the difference between the mean aggregate particle size of the (a) inorganic particles and the mean particle size of the (b) colloidal particles is within 10%.

Description

This invention relates to an ink jet recording element, more particularly to a porous ink jet recording element and a printing method using the element.
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 and 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-receiving 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.
An important characteristic of ink jet recording elements is their need to dry quickly after printing. To this end, porous recording elements have been developed which provide nearly instantaneous drying as long as they have sufficient thickness and pore volume to effectively contain the liquid ink. For example, a porous recording element can be manufactured by cast coating, in which a particulate-containing coating is applied to a support and is dried in contact with a polished smooth surface.
In addition, when a porous recording element is printed with dye-based inks, the dye molecules penetrate the coating layers. However, there is a problem with such porous recording elements in that the optical densities of images printed thereon are lower than one would like. The lower optical densities are believed to be due to optical scatter that occurs when the dye molecules penetrate too far into the porous layer.
World Publication 00/01539 discloses a porous ink jet recording element containing first and second group particles, the first group comprising metal oxide particles which are aggregates of smaller, primary particles with a mean diameter of the aggregates from 100 nm to 500 nm and the second group comprising of particles with a mean diameter less than 50% of the mean diameter of the aggregates in the first group. However, there is a problem with this recording element in that it has a poor dry time as will be shown hereinafter.
It is an object of this invention to provide a porous ink jet recording element that has a good image quality with good gloss and has an excellent dry time.
Another object of the invention is to provide a printing method using the above-described element.
These and other objects are achieved in accordance with the invention which comprise an ink jet recording element comprising a support having thereon a porous image-receiving layer comprising at least 50% by weight of particles and less than 20% by weight of a binder, the particles comprising a mixture of
(a) inorganic particles having a primary particle size of from 7 to 40 nm in diameter which may be aggregated to provide a mean aggregate particle size of up to 500 nm; and
(b) colloidal particles having a mean particle size of from 20 to 500 nm;
By use of the invention, a porous ink jet recording element is obtained that has a good image quality with good gloss and has an excellent dry time.
Another embodiment of the invention relates to an ink jet printing method comprising the steps of:
I) providing an ink jet printer that is responsive to digital data signals;
II) loading the printer with the ink jet recording described above;
III) loading the printer with an ink jet ink composition; and
IV) printing on the image-receiving layer using the ink jet ink composition in response to the digital data signals.
The porous image-receiving layer useful in the invention comprises at least 50% by weight of particles, preferably from 80-90% by weight, and less than 20% by weight of binder. This amount of binder will insure that the layer is porous, i.e., have interconnecting voids so that a solvent in the ink jet ink used in printing on the recording element can travel through the image-receiving layer to a support or base layer if one is present.
Examples of (a) inorganic particles useful in the invention include alumina, boehmite, hydrated alumina, silica, titanium dioxide, zirconium dioxide, clay, calcium carbonate, inorganic silicates or barium sulfate. The particles may be porous or nonporous. In a preferred embodiment of the invention, the (a) inorganic particles are metallic oxides, preferably fumed. Preferred examples of fumed metallic oxides which may be used include silica and alumina fumed oxides. Fumed oxides are available in dry form or as dispersions of the aggregates.
In another preferred embodiment of the invention, the (a) inorganic particles may be in the form aggregated particles. The aggregates are comprised of smaller primary particles 7 to 40 nm in diameter, and are aggregated up to 500 nm in diameter. In still another preferred embodiment, the (a) inorganic particles have a mean aggregate particle size of from 50 nm to 200 nm.
Examples of (b) colloidal particles useful in the invention include alumina, boehmite, hydrated alumina, silica, titanium dioxide, zirconium dioxide, clay, calcium carbonate, inorganic silicates, barium sulfate or organic particles such as polymeric beads. Examples of organic particles useful in the invention are disclosed and claimed in U.S. Patent Application Serial Numbers: 09/458,401, filed Dec. 10, 1999; 09/608,969, filed June 30, 2000; 09/607,417, filed June 30, 2000; 09/608,466 filed June 30, 2000; 09/607,419, filed June 30, 2000; and 9/822,731, filed March 30, 2001. In a preferred embodiment of the invention, the (b) colloidal particles are silica, alumina, boehmite or hydrated alumina. The particles may be porous or nonporous. In another preferred embodiment of the invention, the (b) colloidal particles may be in the form of primary particles. In yet another preferred embodiment of the invention, the mean particle size of the primary particles may range from 20 nm to 500 nm.
In a preferred embodiment of the invention, the first (a) inorganic particles comprise from 5 to 25% by weight of the particle mixture. In another preferred embodiment, the first (a) inorganic particles have a mean aggregate particle size of from 50 nm to 200 nm. In yet another preferred embodiment, the (b) colloidal particles have a mean particle size of from 50 nm to 200 nm.
The above particles are preferred for ink jet recording elements because they possess positively charged surfaces, which are capable of binding anionic ink jet printing dyes, rendering printed images resistant to dye migration due to water and high humidity conditions.
It has been found that the size difference between the (a) first inorganic particles and the (b) colloidal particles determines the dry time of the ink jet recording element. If the mean particle size of the (b) particles is much smaller than the mean aggregate particle size of the (a) first inorganic particles, then the (b) colloidal particles may fill in the void space between the (a) first inorganic particles in the dry coating, which would reduce the porosity of the image-receiving layer. A reduction in porosity of the image-receiving layer would reduce the dry time of the image-recording element.
In general, any binder may be used in the image-receiving layer of the invention. In a preferred embodiment, the binder is a hydrophilic polymer such as poly(vinyl alcohol), poly(vinyl pyrrolidone), gelatin, cellulose ethers, poly(oxazolines), poly(vinylacetamides), partially hydrolyzed poly(vinyl acetate/vinyl alcohol), poly(acrylic acid), poly(acrylamide), poly(alkylene oxide), sulfonated or phosphated polyesters and polystyrenes, casein, zein, albumin, chitin, chitosan, dextran, pectin, collagen derivatives, collodian, agar-agar, arrowroot, guar, carrageenan, tragacanth, xanthan, rhamsan and the like. In another preferred embodiment, the hydrophilic binder is poly(vinyl alcohol). The polymeric binder should be chosen so that it is compatible with the aforementioned particles.
The thickness of the image-receiving layer may range from 5 to 40 µm, preferably from 10 to 20 µm. The coating thickness required is determined through the need for the coating to act as a sump for absorption of ink solvent and the need to hold the ink near the coating surface. The coating may be applied in a single layer or in multiple layers so the functionality of each coating layer may be specified; for example, a two-layer structure can be created wherein the base coat functions as a sump for absorption of ink solvent while the top coat holds the ink.
In a preferred embodiment, the recording element also contains a base layer having at least 50% by weight of inorganic particles. The base layer is coated between the support and the image-receiving layer. In another preferred embodiment, the inorganic particles in the base layer comprise calcium carbonate, magnesium carbonate, barium sulfate, silica, alumina, boehmite, hydrated alumina, clay or titanium oxide. In another preferred embodiment, the inorganic particles in the base layer have an anionic surface charge. In yet another preferred embodiment, the inorganic particles in the base layer have a mean particle size of from 100 nm to 5 µm.
In still another preferred embodiment, the base layer contains a binder such as a polymeric material and/or a latex material, such as poly(vinyl alcohol) and/or styrene-butadiene latex. In still another preferred embodiment, the binder in the base layer is present in an amount of from 5 to 20 weight %. In still another preferred embodiment, the thickness of the base layer may range from 5 µm to 50 µm, preferably from 20 to 40 µm.
After coating, the ink jet recording element may be subject to calendering or supercalendering to enhance surface smoothness. In a preferred embodiment of the invention, the ink jet recording element is subject to hot, soft-nip calendering at a temperature of 65 ° C and pressure of 14000 kg/m at a speed of from 0.15 m/s to 0.3 m/s.
The support for the ink jet recording element used in the invention can be any of those usually used for ink jet receivers, such as resin-coated paper, paper, polyesters, or microporous materials such as polyethylene polymer-containing material sold by PPG Industries, Inc., Pittsburgh, Pennsylvania under the trade name of Teslin ®, Tyvek ® synthetic paper (DuPont Corp.), and OPPalyte® films (Mobil Chemical Co.) and other composite films listed in U.S. Patent 5,244,861. Opaque supports include plain paper, coated paper, synthetic paper, photographic paper support, melt-extrusion-coated paper, and laminated paper, such as biaxially oriented support laminates. Biaxially oriented support laminates are described in U.S. Patents 5,853,965; 5,866,282; 5,874,205; 5,888,643; 5,888,681; 5,888,683; and 5,888,714. These biaxially oriented supports include a paper base and a biaxially oriented polyolefin sheet, typically polypropylene, laminated to one or both sides of the paper base. Transparent supports include glass, cellulose derivatives, e.g., a cellulose ester, cellulose triacetate, cellulose diacetate, cellulose acetate propionate, cellulose acetate butyrate; polyesters, such as poly(ethylene terephthalate), poly(ethylene naphthalate), poly(1,4-cyclohexanedimethylene terephthalate), poly(butylene terephthalate), and copolymers thereof; polyimides; polyamides; polycarbonates; polystyrene; polyolefins, such as polyethylene or polypropylene; polysulfones; polyacrylates; polyetherimides; and mixtures thereof. The papers listed above include a broad range of papers, from high end papers, such as photographic paper to low end papers, such as newsprint.
The support used in the invention may have a thickness of from 50 to 500 µm, preferably from 75 to 300 µm. Antioxidants, antistatic agents, plasticizers and other known additives may be incorporated into the support, if desired.
Coating compositions employed in the invention may be applied by any number of well known techniques, including dip-coating, wound-wire rod coating, doctor blade coating, gravure and reverse-roll coating, slide coating, bead coating, extrusion coating, curtain coating and the like. Known coating and drying methods are described in further detail in Research Disclosure no. 308119, published Dec. 1989, pages 1007 to 1008. Slide coating is preferred, in which the base layers and overcoat may be simultaneously applied. After coating, the layers are generally dried by simple evaporation, which may be accelerated by known techniques such as convection heating.
In order to impart mechanical durability to an ink jet recording element, crosslinkers which act upon the binder discussed above may be added in small quantities. Such an additive improves the cohesive strength of the layer. Crosslinkers such as carbodiimides, polyfunctional aziridines, aldehydes, isocyanates, epoxides, polyvalent metal cations, and the like may all be used.
To improve colorant fade, UV absorbers, radical quenchers or antioxidants may also be added to the image-receiving layer as is well known in the art. Other additives include adhesion promoters, rheology modifiers, biocides, lubricants, dyes, optical brighteners, matte agents, antistatic agents, etc.
The coating composition can be coated so that the total solids content will yield a useful coating thickness, and for particulate coating formulations, solids contents from 10-60% are typical.
Ink jet inks used to image the recording elements of the present invention are well-known in the art. The ink compositions used in ink jet printing typically are liquid compositions comprising a solvent or carrier liquid, dyes or pigments, humectants, organic solvents, detergents, thickeners, preservatives, and the like. The solvent or carrier liquid can be solely water or can be water mixed with other water-miscible solvents such as polyhydric alcohols. Inks in which organic materials such as polyhydric alcohols are the predominant carrier or solvent liquid may also be used. Particularly useful are mixed solvents of water and polyhydric alcohols. The dyes used in such compositions are typically water-soluble direct or acid type dyes. Such liquid compositions have been described extensively in the prior art including, for example, U.S. Patents 4,381,946; 4,239,543 and 4,781,758.
The following examples further illustrate the invention.

Control Element C-1 (Mixture of particles with greatly different particle sizes in the image-receiving layer) (WO 00/01539)

A coating solution for a base layer was prepared by mixing 100 dry g of precipitated calcium carbonate Albagloss-s® (Specialty Minerals Inc.) as a 70% solution and 8.5 dry g of silica gel Gasil® 23F (Crosfield Ltd.) with 0.5 dry g of poly(vinyl alcohol) Gohsenol® GH-17 (Nippon Gohsei Co., Ltd.) as a 10% solution and 5 dry g of styrene-butadiene latex CP692NA® (Dow Chemicals) as a 50% solution. The solids of the coating solution was adjusted to 35% by adding water.
The base layer coating solution was bead-coated at 25°C on a base paper, Nekoosa Solutions Smooth ® (Georgia Pacific), Grade 5128 (Carrara White ®, Color 9220), basis weight 150 g/m², and dried at 60°C by forced air. The thickness of the base coating was 25 µm or 27 g/m².
A coating solution for the image-receiving layer was prepared by mixing 100 dry g of colloidal silica Ludox® Cl (DuPont Corp.) as a 30% solution and 30 dry g of fumed alumina Cab-O-Sperse® PG003 (Cabot Corp.) as a 40% solution with 4 dry g of poly(vinyl alcohol) Gohsenol® GH-17 (Nippon Gohsei Co. Ltd.) as a 10% solution and 0.1 dry g of 2,3-dihydroxy-1,4-dioxane (Clariant Corp). The solids of the coating solution was adjusted to 20% by adding water. The mean particle size of the Ludox® Cl colloidal silica was only 10 nm while the mean aggregate size of the Cab-O-Sperse® PG003fumed alumina was 130 nm.
The image-receiving layer coating solution was coated on top of the base layer described above. The recording element was then dried at 60 ° C by forced air to yield a two-layer recording element. The thickness of the image-receiving layer was 8 µm or 8.6 g/m².
The recording element was then calendared at 0.15 (m/min) with a 14000 (kg/m) pressure at 60° C.

Element I of the Invention

This element was prepared the same as Control Element C-1 except that 100 dry g of alumina Dispal® 14N4-80 (Condea Vista Co.) as 20% solution was added in place of Ludox® Cl to the image-receiving layer coating solution. The mean particle size of the Dispal® 14N4-80 was 120 nm and the mean aggregate size of the Cab-O-Sperse® PG003 was 130 nm (the size difference is within 10%).

Element 2 of the Invention

This element is the same as Element 1 of the invention except that the amount of Cab-O-Sperse® PG003 was 10 dry g.

Element 3 of the Invention

This element is the same as Element 1 of the invention except that the amount of Cab-O-Sperse® PG003 was 20 dry g.

Comparison Element C-2

This element was prepared the same as Element 1 of the invention except that it omitted the Dispal® 14N4-80.

Comparison Element C-3

This element was prepared the same as Element 1 of the invention except that it omitted the Cab-O-Sperse® PG003.

Gloss

The above recording elements were measured for 60° specular glossiness using a Gardener® Gloss Meter.

Printing

Images were printed using an Epson Stylus Color 740 printer for dye-based inks using Color Ink Cartridge S020191/IC3CL01. The images comprised a series of cyan, magenta, yellow, black, green, red and blue strips, each strip being in the form of a rectangle 0.8 cm in width and 20 cm in length.

Dry Time

Immediately after ejection from the printer, a piece of bond paper was placed over the printed image and rolled with a smooth, heavy weight. Then the bond paper was separated from the printed image. The length of the color strip transferred to the bond paper was measured and is proportional to the time needed for the printed image to dry. The dry time is rated as 1 when there is no transfer of the inks to the bond paper, and is considered acceptable. If there is a full transfer of at least one color strip, the dry time is rated as 5, and is unacceptable. Intermediate transfer lengths are rated between 1 and 5.

Image Quality

The image quality was evaluated subjectively. Coalescence refers to the non-uniformity or puddling of the ink in solid filled areas. Bleeding refers to the inks flowing out of its intended boundaries. The following results were obtained:

Element	Gloss	Dry Time	Image Quality
1 (Invention)	47	1	No coalescence and no bleeding
2 (Invention)	48	1	No coalescence and no bleeding
3 (Invention)	48	1	No coalescence and no bleeding
C-1 (Control)	40	3	Bad coalescence and bad bleeding
C-2 (Comparison)	10	1	No coalescence and no bleeding
C-3 (Comparison)	45	2	Some coalescence and some bleeding

The above data show that the Elements of the invention had high gloss, good dry time and good image quality, as compared to the control and comparison elements which did not have all of these properties at the same time.

Claims

An ink jet recording element comprising a support having thereon a porous image-receiving layer comprising at least 50% by weight of particles and less than 20% by weight of a binder, said particles comprising a mixture of

(a) inorganic particles having a primary particle size of from 7 to 40 nm in diameter which may be aggregated to provide a mean aggregate particle size of up to 500 nm; and

(b) colloidal particles having a mean particle size of from 20 to 500 nm;

and wherein the difference between said mean aggregate particle size of said inorganic particles and said mean particle size of said colloidal particles is within 10%.
The recording element of Claim 1 wherein said (a) inorganic particles are alumina, boehmite, hydrated alumina, silica, titanium dioxide, zirconium dioxide, clay, calcium carbonate, inorganic silicates or barium sulfate.
The recording element of Claim 1 wherein said (b) colloidal particles are alumina, boehmite, hydrated alumina, silica, titanium dioxide, zirconium dioxide, clay, calcium carbonate, inorganic silicates, barium sulfate or organic particles.
The recording element of Claim 1 wherein said (a) inorganic particles comprise fumed alumina or fumed silica.
The recording element of Claim 1 wherein said (a) inorganic particles comprise from 5 to 25% by weight of said mixture.
The recording element of Claim 1 wherein said (b) colloidal particles comprise alumina, boehmite, hydrated alumina or silica.
The recording element of Claim 1 wherein said (a) inorganic particles have a mean aggregate particle size of from 50 nm to 200 nm.
The recording element of Claim 1 wherein said (b) colloidal particles have a mean particle size of from 50 nm to 200 nm.
The recording element of Claim 1 wherein said (a) inorganic particles and said (b) colloidal particles are positively charged.
An ink jet printing method comprising the steps of:

I) providing an ink jet printer that is responsive to digital data signals;

II) loading said printer with the ink jet recording of Claim 1;

III) loading said printer with an ink jet ink composition; and

IV) printing on said image-receiving layer using said ink jet ink composition in response to said digital data signals.