WO1999026790A1

WO1999026790A1 - Image receiving element

Info

Publication number: WO1999026790A1
Application number: PCT/US1998/006821
Authority: WO
Inventors: Susan K. Yarmey; Larry J. Bresina; Michael L. Steiner; Khanh Huynh; Ronald J. Moudry
Original assignee: Imation Corp.
Priority date: 1997-11-24
Filing date: 1998-04-06
Publication date: 1999-06-03

Abstract

An ink jet receptor that has a very thin gelatin layer over an ink absorptive layer to provide good dye fade resistance as well as good dry time.

Description

IMAGE RECEIVING ELEMENT

Field of the Invention This invention relates to an image receiving element and, more specifically, a receptor for ink jet printing.

Background of the Invention

As ink jet technology has improved, ink jet printing is being used for increasingly critical imaging applications, such as proofing, high end graphics, etc. One key factor in controlling image quality is the receptor. Desirably the receptor enables the ink image to dry rapidly. Slow drying may lead to smearing of the undried image.

Another issue that becomes critical in certain applications is the image stability (also referred to as "dye fade") over time. Dye fade can lead to unacceptable image quality if it is severe or if it occurs over relatively short time periods.

A receptor for ink jet printing typically comprises a support material bearing an ink receiving material. A variety of compounds and mixtures have been proposed for use as the ink receiving material. For example. U.S. Patent No. 3,889.270 describes an ink-receiving layer consisting of a protein, polysaccharide, cellulose, a cellulose derivative, polyvinyl alcohol, a copolymer of vinyl alcohol, gelatin, albumen, casein or silica gel. One problem with gelatin receiving layers is that such layers do not yield good ink jet printed images, particularly in portions having relatively large areas of high density inks. This appears to be due to the relatively slow rate of water absorbency from the inks. This allows puddling to occur when inks are applied because a substantial amount of aqueous liquid must be absorbed by the receptor layer.

Gelatin has been blended with other water absorptive polymers to improve the absorption rate into the coating (i.e. dry time). For example, U.S. Patent No.5, 141, 599 discloses a receptor layer which contains a mixture of gelatin and starch. U.S. Patent No. 4,503,111 teaches the use of polyvinylpyrrolidone (PVP) blended with a compatible matrix-forming polymer (swellable by water and insoluble at room temperature but soluble at elevated temperatures). The matrix forming-polymer described includes gelatin or polyvinyl alcohol (PVA). Applicants have found that such blends have poor image stability.

Other patents, such as U.S. Patent Nos. 5,389,723 and 5,342,688, describe a composition that is capable of forming liquid-absorbent, semi-interpenetrating networks, hereinafter referred to as SIPNs. The SIPNs disclosed are polymeric blends wherein at least one of the polymeric components is crosslinked after blending to form a continuous network throughout the bulk of the material, and through which the uncrosslinked polymeric component or components are intertwined in such a way as to form a macroscopically homogenous composition. Applicants have found that these systems show acceptable dry times but their image stability is not as good as a gelatin receiving layer.

Use of two layer receiving materials has also been discussed. US 5,567,507 and WO 96/26840 disclose an ink-receptive coating comprising at least two layers, a base layer for ink absorption, and a thin upper layer comprising methylcellulose, hydroxypropyl cellulose or blends of those materials. This coating shows a fast dry time, but Applicants have found it to have poor image stability. Additional publications (JP 63039373, JP 62263084, JP 61035988) discuss the use of at least two coating layers for inkjet media where the ink absorption rate of the top receiving layer is higher than the ink absorption of the lower receiving layer. Applicants have found that such systems appear to have poor image stability. U.S. Patent 4,877,678 teaches an ink jet receptor having a first water absorbing layer which has a thickness of 3 to 30 μm and a second water-absorption controlling layer which has a thickness of 5 to 50 μm. The second layer comprises a water absorptive inorganic filler in a polymeric binder. The binder may be gelatin. JP 60259488 discloses an inkjet recording element in which surface tack is adjusted by (i) fixing powder on the surface, (ii) applying a coating of starch, gelatin, polyamide, melamine resin, PVA, etc. over the surface or (iii) using select materials in the ink acceptance layer. JP 2055186 discloses a system having an ink holding layer and an ink penetration layer. The ink penetration layer is 5-150 μm thick and contains porous particles in a binder selected from PVA acrylic resins, PVP, starch, methylcellulose, gelatin, etc. JP 1262183 discloses a system having an ink accepting layer and a protecting layer which is cured with an anti-diffusive crosslinking agent. The binder for the protective layer may be gelatin, starch, methyl cellulose, or water-soluble synthetic polymer.

Summary of the Invention

Applicants have discovered that a receptor having a very thin layer of gelatin over a layer of a water absorptive material provides excellent dye stability without substantial deterioration in dry time for water based inks. Specifically, this invention is an ink receiving element comprising a substrate, a first layer of a first ink receiving material on the substrate, and a second layer of a second ink receiving material over the first layer, the second ink receiving material comprising gelatin. According to one embodiment the second layer consists essentially of gelatin, preferably consisting only of gelatin.

According to a second embodiment, the second layer may include other materials such as matting agents and the second layer is coated at a dry coating weight of less than 0.65 g/ft². According to yet another embodiment, the second layer may include other materials such as matting agents and the second layer has a thickness of less than 5 μm. According to yet another embodiment, the invention is a method of forming an image on the above described receptors by use of an ink jet apparatus. While the receptor of this invention is primarily concerned with performance with aqueous based inks, it is also contemplated that the receptor may be used with solvent based inks.

Detailed Description of the Invention

The substrate may be any material that provides a suitably strong support for the ink receiving layers. Examples of suitable substrates include paper, cloth, polymers, metals, and glass. Thin flexible sheets are preferred. Paper is useful when an opaque support is desired, while polymeric films may provide translucent or transparent supports. The thickness of the substrate is preferably in the range of 0.05 to 1.0 mm. The substrate may be treated with a subbing layer such as a primer or an antistatic layer. An anti-curl layer may be coated on the back side of the substrate. The first ink receiving material may be any water absorptive ink receiving material known in the art. Hydrophilic polymers which absorb water at room temperature in an amount of preferably at least 1.0, more preferably at least 1.5, times the weight of the polymer are preferred. Non-limiting examples of suitable materials include polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyhydroxyethvlmethacrylate, cellulose, cellulose derivatives, polymers containing acrylic acid, and semi-interpenetrating polymeric networks as disclosed in US 5,389,723; US 5,342,688; WO 96/26840; and WO 96/26841. The first layer preferably has a thickness of about 5 to about 75 μm.

The second ink receiving material comprises as a major component gelatin. Gelatin is a derived protein which, though not homogeneous, is chemically well defined. It is the main product of mild, but irreversible collagenolytic breakdown. When tissues which contain collagen are subjected to mildly degradative processes, usually involving treatment with alkali or acid followed or accompanied by some degree of heating in the presence of water, the systematic fibrous structure of the collagen is broken down irreversibly. The main product of this change has characteristic properties. It forms a highly viscous solution in water, which sets to a gel on cooling and its chemical composition is, in many respects, closely similar to that of its parent collagen. Thus, gelatin is a protein and, in common with all proteins, is made up of amino acids joined together by peptide linkages to form polymer chains. The nature of the side chain group will vary for different amino acids. Gelatin is composed of 18 different amino acids and its composition is remarkably consistent, irrespective of its physical properties or whether it is derived from hide/skin or bone collagen or manufactured by an acid or alkali process. Certain features of the amino acid composition which are characteristic of gelatin and its parent protein collagen are the high glycine content (approximately one third of the total number of residues), the high hydroxyproline content; the presence of hydroylysine, and the deficiency of sulphur-containing amino acids and tryptophan. The term gelatin is applied not only to the "protein" but also to the commercial product which contains, not only the protein as its main constituent but also smaller amounts of various inorganic and organic impurities. Commercially available sources of gelatin include Photographic Gelatin 17332 (referred to herein as Gl), 17907 (G2), and 19720 (G5) from Systems Bio Industries, Inc. Langhorne, PA; Photographic Gelatin P-4117 (G3) from Nitta Gelatin Inc. Osaka, Japan; Hydrolized Gelatin D4572 (G4), Tilapia Fish Skin Gelatin (OCL REF 96411) (G6), Low Viscosity Deionised Gelatin (G7) and Gelatin Bone 669 Photographic (G8) from Croda Colloids Ltd. Cheshire, England.

Applicants have found that even very thin layers of gelatin improve dye fade resistance. However, the second layer should not be so thick as to have a long dry time. Preferably, the thickness is less than 5 μm, more preferably, less than 4 μm. Due to the coating process the interface between the first and second layers may be graduated rather than a sharp interface. Therefore, it is also helpful to define the thickness by coating weight of the second layer. Preferably, the coating weight is less than 0.65 g/ft² (lg/ft² = 10.8 g/m²), more preferably less than 0.55 g/ft². Additives such as surfactants, plasticizers, antistatic agents, buffers, coating aids, matting agents, particulates for managing mechanical processing of the ink receiving element, hardeners, colorants, viscosity modifiers, preservatives, and the like may also be added to either or both the first and second layers. The gelatin layer could be lightly crosslinked by several methods known in the art. One way would be to use a cross-linking agent (e.g. formaldehyde) incorporated in the coating composition used to form the ink-receiving layer. The ink-receiving layer would be non-blocking yet would have to rapidly absorb the water-based liquid ink that is applied thereto. The gelatin layer must not harden to too high a degree, or the ink-receiving layer will not rapidly absorb the ink and may cause the ink to pool at the surface. These receptors function well as receptors for ink jet printing or image forming. Any suitable inkjet printer or the like may be used. Suitable examples of such printers include Iris Realist 5030 (Iris Graphics), HP Deskjet 855C (Hewlett Packard), and Epson Stylus Pro (Epson America).

EXAMPLES In the following experiments, dye stability and dry time (absorption rate into the coating) are measured for a series of different materials. Dye stability measurements are discussed within each sample set. All density measurements were done by a Gretag spectrophotometer (either Gretag SMP 50 LT or Gretag

Spectroscan and Spectrolino). dE = ΔE*_atø = square root of [(ΔL*)²+ (Δa*)² +

(Δb*)²] where ΔL*, Δa*, and Δb* represent the change in L*, a*, and b* between the original and aged samples. ΔE*_atø = the CIE [Commission Internationale de l'Eclairage (International Commission of Illumination)] 1976 (L*a*b*) color difference or CIELAB color difference where a 3D model is used whereby L is the lightness axis, a is the red-green axis, and b is the yellow-blue axis. Image stability was determined for light fade using a fluorescent fade box at 1500 ft-cd in a controlled environment (21°C and 50%RH) for 48 or 72 hours or for dark fade, 24 hours in the dark at ambient conditions.

Dry times were evaluated using the following procedure. A 0.5 cm wide and 23.6 cm long magenta stripe with an optical density (OD) of 2.08 was printed on the coating. The printer used is the HP Deskjet 855C (Hewlett-Packard, Palo Alto, CA) which takes approximately 3 minutes to print this stripe. After waiting some designated amount of time, a Xerographic copier paper (Cascade™ X-9000, Boise Cascade Paper Division) is placed on the stripe and a metal roller of parameters: 6.4cm wide, 10.1cm diameter and 4.2kg weight is rolled over the copier paper once in a single direction. The copier paper is then removed from the coated paper and the density of the magenta color on the copier paper is measured at a specified place. By taking into account the time off the printer before applying the paper as well as where the measurement on the paper is taken, one can determine the length of time it takes for the ink to be absorbed into the coating.

All experimental coatings were done over a polyethylene coated paper base. The specific gelatins used are identified as G1-G8 having the identities listed as above. In all cases when gelatin was used, the gelatin was placed in deionized water for 30 minutes at ambient conditions and then heated at 50°C for at least one hour. Triton™ X-100, a surfactant (available from Rohm and Haas) was then added and the solution was coated warm (at around 40°C). If gelatin was being blended with another polymer, the gelatin was placed in deionized water for 30 minutes at ambient conditions and then heated at 50°C for at least one hour. The other polymer was dissolved in deionized water and then added to the 50°C gelatin solution. Then the Triton™ X-100 was added and the entire solution was coated at around 40°C. Coating weights were determined by the Meyer rod number, wet thickness, % solids of solutions and material density (1.36 for gelatin) or by empirically weighing the coating.

Example 1 In this series of experiments, polyvinylpyrolidone, manufactured by ISP

Technologies and sold under the tradename PVP-K90 (PVP) and gelatin (Gl), were used.

In Comparative Sample #1C, a coating solution of 10% PVP in deionized water containing Triton™ X-100 at a level of 2 drops for every gram of PVP was coated using a knife coater (at 5 mil (127 μm) gap) and dried at 60°C for 5 minutes.

In Comparative Sample #2C, a coating solution containing 10% Gl in deionized water and Triton™ X-100 at a level of 2 drops for every gram of Gl was coated using a knife coater (5 mil (127 μm) gap) and dried at 60°C for 7 minutes.

Comparative Sample #3C was a 10% coating solution of solids containing one part (by weight) of PVP and one part Gl in deionized water. Triton™ X-100 was used at a level of 2 drops for every gram of solid. This solution was coated using a knife coater (5 mil (127 μm) gap) and dried at 60°C for 5 minutes. Comparative Sample #4C was initially prepared the same as Comparative

Sample #2C except with the addition of formaldehyde (0.34 grams per 10 grams of gelatin). A hardener was necessary or the Gl could not be overcoated (the over coat layer solvent attacked the gelatin underlayer). Then, the coated surface was overcoated with a 10% solution of PVP in deionized water with Triton™ X-100 at a level of 2 drops for every gram of PVP using a 22 Meyer rod and dried for 5 minutes at 60°C.

In Sample #1, PVP was coated as stated in Comparative Sample #1C. Then, the coated surface was overcoated with a 10% solution of Gl in deionized water with Triton™ X-l 00 at a level of 2 drops for every gram of gelatin using a 18 Meyer bar, dried for 60°C for όminutes

In this Example, Iris Realist 5030 (Iris Graphics, Bedford, MA) printer and inks were used to image. Image stability was determined using a fluorescent fade box at 1500 ft-cd (1 ft-cd = 1 foot candle corresponds to a flux density of 1 Lumen/square foot = a flux density of 27.3 Lumens/square meter) in a controlled environment (21 °C and 50% relative humidity) for 48 hours. The average dE refers to an averaging of primary and secondary colors as well as black and 3 color black for 6 steps of color throughout the density range from 5% to 100% coverage. Duplicates of each formulation were included in the averaging of dE. The maximum dE refers to the average of the highest dE observed for any color, any step for each replicate. The gelatin alone layer shows good image stability while the PVP alone layer shows poor image stability. When incorporating PVP into the Gl layer at 50 weight %, a small improvement in image stability is observed relative to the PVP alone coating; however, the image stability is still poor when compared to the Gl alone layer. When overcoating Gl with PVP, dye stability is as poor as the PVP alone layer. When overcoating PVP with Gl, dye stability improved to almost that of the Gl alone.

Dry times show that PVP is substantially faster at absorbing the ink than Gl. And, that blending or overcoating the Gl layer with PVP improves the dry time significantly when compared to the gelatin only layer. Overcoating PVP with gelatin gave a slower dry time than PVP alone.

Example 2 In this series of experiments, the standards shown are X, a two layer construction having a substrate, a first layer with a coating weight of 2.04g/ sq. ft., and a second layer with a coating weight of .08g/ sq. ft. and Y, a one layer construction having substrate and layer with a coating weight of 1.3g/ sq. ft. These coating weights were determined empirically by weighing the coatings. For X, the substrate is polyethylene coated paper of 185 microns with a very thin subbing layer of gelatin to promote adhesion. For X, the bottom layer solution was made following example 2 in patent WO 96/26840 with the following changes: Pycal 94 used at 17 g per lOOg polymer and the coating solution was made with 75% water and 25%o ethanol (160 proof). The top layer solution was made following example 9 in WO 96/26841 with the following specifics: 1.2 g of Methocel K15M, 2.1g of Ludox LS, 0.7g of PEI (water free)/ PTSA (1:2.2), 0.13g of 8μ polymethylmethacrylate beads, 0.05g of Zonyl (Dupont), 76.4g of water, and 19.6g of 160 proof ethanol. The coating method used was extrusion. For Y, the substrate was a polyethylene coated paper base of 147 microns with a very thin subbing layer of gelatin to promote adhesion. Solution was made following example 1 in patent US 5,342,688 with the following exceptions: level changes of copolymer B at 55% solids, Vinyl™ 523 at 30% solids and Gohsenol™ at 10% solids; polyethylene glycol 600 (Aldrich Chem. Co., Inc.) added at 3% solids; no polymethylmethacrylate beads were added. The coating method used was extrusion.

Comparative Sample #1C was X. Comparative Sample #2C was Y. In comparative sample #3C, the X bottom layer was coated. In comparative samples #4C-#6C, coating solutions (10% in deionized water) containing Y solution as described above and Gl at the described weight percent ratios were made. Triton™ X-100 was added at a level of 2 drops per gram of solid. These solutions were coated on a knife coater at a 5 mil (127 μm) gap and dried at 60°C for 5 minutes. In comparative sample #7C, a 10% solution of G 1 with Triton™ X- 100 (added at a level of 2 drops per gram of solid) in deionized water was knife coated at a 5 mil (127 μm) gap and dried at 60°C for 8 minutes.

For samples #1 and #2, coatings of comparative sample #2C and comparative sample #3C were overcoated with Gl at 10% solids in deionized water with Triton™ X-100 (2 drops per gram Gl) using a 16 Meyer bar and dried at 60°C for 6 minutes.

Iris Realist 5030 (Iris Graphics, Bedford, MA) printer and inks were used. Image stability was determined using a fluorescent fade box at 1500 ft-cd (1 ft-cd = 1 foot candle corresponds to a flux density of 1 Lumen/square foot = a flux density of 27.3 Lumens/square meter) in a controlled environment (21°C and 50% relative humidity) for 48 hours. The average dE refers to an averaging of primary and secondary colors as well as black and 3 color black for 4 steps of color throughout the density range from 25% to 100%) coverage. Duplicates of each formulation were included in the averaging of dE. The maximum dE refers to the average of the highest dE observed for any color, any step for each replicate.

When incorporating Gl into the Y layer, some improvement in the dye stability was observed when compared to the Y layer alone. However, the dry time of the Y layer was degraded by incorporating Gl . By overcoating the Y or X layer, a large improvement was seen in dye stability. In the case of example 2, sample #2 (Gl overcoating), the dye stability was increased to nearly that of the Gl alone layer. The dry times were improved with the Gl overcoatings.

Example 3 In example 3, comparative sample #1C, Y coating was made as described in Example 2, comparative sample 2C. In example 3, sample 1, comparative sample lc was then overcoated with Gl as described in example 2, sample 1 except using a 10 Meyer bar.

Iris Realist 5030 (Iris Graphics, Bedford, MA) printer and inks were used. Image stability for dark fade was determined by measuring the ink densities within the first hour after printing, placing the samples in the dark at ambient conditions and, after 24 hours, measuring the densities again. The average dE refers to an averaging of primary and secondary colors as well as black and 3 color black for 4 steps of color throughout the density range from 25% to 100% coverage. Duplicates of each formulation were included in the averaging of dE. The maximum dE refers to the average of the highest dE observed for any color, any step for each replicate.

When overcoating gelatin over the original Y receptor, dE values (both average and maximum) were greatly decreased, showing a vast improvement in image stability. The dry times were improved with the Gl overcoatings.

Example 4

In this experiment, comparative samples #1C, #2C, #3C are used that were described in example 2, comparative samples #1C, #3C, #2C, respectively.

Sample #1 was prepared as described in example 2, sample #2. Samples #2-#4 were prepared as described in example 2, sample #1. The only difference being that gelatin was coated with a 18 Meyer rod and different gelatins (as described in Table 1) were used for samples #3 and #4.

HP Deskjet 855C (Hewlett-Packard, Palo Alto, CA) printer and inks were used. Image stability was determined using a fluorescent fade box at 1500 ft-cd in a controlled environment (21°C and 50%relative humidity) for 72 hours. The average dE refers to an averaging of primary and secondary colors as well as black and 3 color black for 4 steps of color with densities ranging from mid-tones to highest density. Duplicates of each formulation were included in the averaging of dE. The maximum dE refers to the average of the highest dE observed for any color, any step for each replicate.

When gelatin was used as an overcoat for the X (bottom layer) or Y formulations, an increase in dye stability was demonstrated. For the HP inks, the gelatin overcoat greatly decreased the dE values (both average and maximum).

The magnitude of the dye stability effect was independent of the type of gelatin used.

Example 5: In this experiment, comparative samples #1C and #2C are used that were described in example 2, comparative samples #1C and #3C, respectively. In comparative sample #3C, a coating solution of 10% solids of polyvinyl alcohol (PVA) manufactured by Air Product and Chemicals and sold under the tradename Airvol 523 in deionized water was coated using a knife coater (at 5 mil (127 μm) gap) and dried at 60°C for 5 minutes. In comparative sample 4C, a coating solution of 10% solids of polyvinyl alcohol (PVA) sold as Gohsenol™ (from Nippon Gohsei) was coated over Y using a 22 Meyer bar and dried at 60°C for 5 minutes.

Samples #l-#5 used were described in example 2, sample #2. The only difference being that gelatin was coated with a 18 Meyer rod and different gelatins as described above were used. Epson Stylus Pro (Epson America, Torrance, CA) printer and inks were used. Image stability was determined using a fluorescent fade box at 1500 ft-cd in a controlled environment (21°C and 50%relative humidity) for 72 hours. The average dE refers to an averaging of primary and secondary colors as well as black and 3 color black for 4 steps of color with densities ranging from mid-tones to highest density. Duplicates of each formulation were included in the averaging of dE. The maximum dE refers to the average of the highest dE observed for any color, any step for each replicate. The sample using PVA showed poor dye stability and a slow dry time. When gelatin was used as an overcoat for the X (bottom layer) formulation, an increase in dye stability was demonstrated. For the Epson inks, the gelatin overcoat greatly decreased the dE values (both average and maximum). In the Epson inks, certain types of gelatin had somewhat differing results in the magnitude of the reduction in both the average and maximum dE values. The magnitude of the dye stability effect is somewhat dependent on the ink and gelatin type.

Table 1

* Significant magenta color is still observed.

Example 6: In this experiment, Gl was coated at different coating weights over the Y formulation (which was coated as described in Example 2, sample #2C). For samples #l-#3, Gl was overcoated using an extrusion method and coating weight was measured. For sample #4-#6, Gl was overcoated as described in Example 2, sample #1 with the difference being the Meyer rod number (22, 30 and 36 respectively). Iris Realist 5030 (Iris Graphics, Bedford, MA) printer and inks were used. Image stability was determined using a fluorescent fade box at 1500 ft-cd in a controlled environment (21°C and 50%relative humidity) for 48 hours. The average dE refers to an averaging of primary and secondary colors as well as black and 3 color black for 4 steps of color throughout the density range from 25% to 100% coverage. Duplicates of each formulation were included in the averaging of dE. The maximum dE refers to the average of the highest dE observed for any color, any step for each replicate.

In this series of experiments, it is shown that the dye stability improves and then levels off as the gelatin overcoat coating weight is increased (Table 2). Table 2 - Dye Stability with varying thickness of gelatin (Iris inks)

Example 7: In this experiment, Gl was coated over Y formulation as described in Example 2, sample #1. The only difference was the Meyer rod number: sample #1, 10; sample #2, 16; sample #3, 30; and in sample #4, a knife coater was used at a 5 mil (127 μm) gap. For sample #4, coating weight was measured.

This experiment shows that slower dry times are recorded as the coating weight of the gelatin overcoat is increased (Table 3).

Table 3 - Dry times with varying thicknesses of gelatin

Claims

What is claimed is:

1. An ink receiving element comprising a substrate, a first layer of a first ink receiving material on the substrate, and a second layer of a second ink receiving material over the first layer, the second ink receiving material consisting of gelatin.

2. The element of claim 1 wherein the second layer has a thickness less than 5 ╬╝m.

3. The element of claim 1 wherein the second layer has a coating weight less than 0.65 g/ft².

4. The element of either claims 1, 2 or 3 wherein the ink image is applied using an inkjet apparatus.

5. The element of either of claims 1, 2 or 3 wherein the second ink receiving material further comprises a matting agent.

6. The element of either of claims 1, 2 or 3 wherein the first ink receiving material is a hydrophilic polymer which absorbs water at room temperature in an amount equal or greater to the weight of the polymer.

7. The element of either of claims 1, 2 or 3 wherein the first ink receiving material is selected from the group consisting of polyvinyl alcohol, polyvinylpyrrolidone, polyhydroxyethylmethacrylate, cellulose, cellulose derivatives, polymers containing acrylic acid and/or semi-interpenetrating polymeric networks.

8. A method for forming an image comprising the steps of a) providing a receptor material which comprises a substrate, a layer of a first ink receiving material on the substrate, and a second layer of a second ink receiving material coated over the first layer, wherein the second layer consists of gelatin, b) applying an ink to the receptor material in an image-wise manner.

9. The method as in claim 9 wherein the second layer has a thickness less than 5 ╬╝m.

10. The method as in claim 9 wherein the second layer has a coating weight less than 0.65 g/ft².

11. The method of either of claims 8, 9 or 10 wherein the applying step comprises use of an inkjet printing apparatus.