CA2046572C - Recording sheets - Google Patents

Abstract

Disclosed is a recording sheet which comprises, in the order stated, an ink receiving layer, a base sheet, a heat absorbing layer, and an anticurl layer The recording sheet can be transparent or opaque, and can be used in a wide variety of printing and imaging processes. The recording sheet exhibits little or no curling, even after exposure to heat and/or a wide range of relative humidities.

Description

2~ 4 6572 RECORDING SHEETS
BACKGROUND OF THE INVENTION
The present invention is directed to sheets suitable as receiving substrates in printing and imaging processes. More specifically, the present invention is directed to recording sheets sultable for printing and imaging processes which contain layers of heat resistant polymers. One embodiment of the present invention is directed to a recording sheet which comprises, in the order stated, an ink receiving layer, a base sheet, a heat absorbing layer, and an anticurl layer.
Recording sheets suitable for various printing and ima~qing p,u.,esses are known. For example, U.S. Patent 4,528,242 (Burwasser) discloses an ink jet recording l~d~ Jd~nCy capable of absorbing colored, aqueous-miscible inks to provide pe~ d"e"L smear-resistant images. The transparency includes a transparent resinous support and a coating which is clear and comprises a mixture of a carboxylated polymer or copolymer having a molecular weight of about 50,0û0 to 1 million, and a polyalkylene glycol having an average molecular weight of about 5,000 to 25,000, with the glycol being present in an amount of about 5 to about 70 percent of the polymer.
In addition, U.S. Patent 4,547,405 (Bedell et al.) discloses an ink jet recording sheet comprising a transparent support carrying a layer comprising 5 to 100 percent by weight of a coalesced block copolymer latex of polyvinyl alcohol with polyvinyl (benzyl ammonium chloride) and 0 to 95 percent by weight of a water soluble polymer selected from the group consisting of polyvinyl alcohol, polyvinyl pyrrolidone, and copolymers thereof.
Further, U.S. Patent 4,555,437 (Tanck) discloses a ,a"~,a,t:"l recording medium which c~ es a conventional ~lal~spal~l~cy base material coated with hydroxy~ se and optionally cûntaining one or mûre additional polymers compatible therewith .
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204657~
AddiLionr"y, U.S. Patent 4,575,465 (Viola) discloses an ink jet recording sheet comprising a transparent support carrying a layer comprising up to 5û percent by weight of vinylpyridine/vinylbenzyl quaternary salt copolymer and a hydrophilic polymer selected from the group consisting of gelatin, polyvinyl alcohol, and hydroxypropyl cellulose and mixturesthereof.
U.S. Patent 4,578,285 (Viola) discloses a printing substrate adapted to receive ink droplets to form an image generated by an ink jet printer which comprises a transparent support carrying a layer comprising at least 7û
percent by weight polyurethane and 5 to 3û percent by weight of a polymer selected from the group consisting of polyvinylpyrrolidone, polyvinylpyrrolidone/vinyl acetate copolymer, poly(ethyleneoxide), gelatin, and polyaccylicacid.
In addition, U.S. Patent 4,592,954 (Malhotra~ discloses a ~ ,ua~t:"-,~
for ink jet printing which comprises a supporting substrate and thereover a coating consisting essentially of a blend of carboxymethyl cellulose and polyethylene oxides. This patent also discloses papers for use in ink jet printing which comprise a plain paper substrate and a coating thereover consisting essentially of polyethylene oxides.
Further, U.S. Patent 4,649,064 (Jones) discloses a rapid-dryincJ imaJe recording element adapted for water based liquid ink marking in devices such as pen plotters, ink jet printers and tlle like. The element comprises a support having thereon a hydrophilic ink receiving layer which is crosslinked to a degree sufficient to render it nonblocking and waterfast while permitting it to absorb rapidly a water-based liquid ink. The element is used in combination with a water-based liquid ink that comprises a water-dispersable crosslinkable colorantJresin composition and the ink receiving layer contains a crosslinking agent which crosslinks the colorant .~

204~572 resin composition to render the markings smear resistant, abrasion resistant, and waterfast.
Addi~iol1 "y, U.S. Patent 4,781,985 (Desjarlais) discloses an ink jet transparency which comprises a substantially transparent resinous support such as a polyester film and a substantially clear coating thereon which includes a specific fluorosurfactant.
U.S. Patent 4,887,097 ~Akiya et al.) discloses a recordin~ medium having a substrate and an ink receiving layer provided on the substrate, wherein the ink receiving layer contains, in combination, solvent soluble resin (A) that is capable of absorbing water in an amount of 0.5 times or more as much as its own weight and is substantially water insoluble, and particles of solvent insoluble resin (B) that is capable of absorbing water in an amount of 50 times or more as much as its own weight In addition, U.S. Patent 4,865,914 (Malhotra) discloses a Lldr~
which comprises a supporting substrate and a blend which comprises polyethylene oxide and carboxymethyl ce!lulose together with a component selected from the group consisting of (1) hydroxypropyl cellulose; (2) vinylmethyl ether/maleic acid copolymer; (3) carboxymethyl hydroxyethyl cellulose; (4) hydroxyethyl cellulose; (5) acrylamide/acrylic acid copolymer; (6) cellulose sulfate; (7) poly(2-acrylamido-2-methyl propane sulfonic acid); (8) poly(vinyl alcohol); (9) poly(vinyl pyrrolidone);
and (1û) hydroxypropyl methyl cellulose. Papers with these coatings are also disclosed.
Additional disclosures concerning recording sheets are disclosed in, for example, U.S. Patent 3,535,112, U.S Patent 3,539,340, U.S. Patent 4,071,362, U.S. Patent 4,085,245, U.S. Patent 4,259,422, U.S. Patent 4,489,122, U.S. Patent 4,526,847, U.S. Patent 4,547,405, U.S. Patent 4,575,465, U.S. Patent 4,770,934, U.S. Patent 4,865,914, U.S. Patent 3,488,189, U.S. Patent 3,493,412, U.S. Patent 3,619,279, U.S. Patent 3,539,341, U.S. Patent 3,833,293, U.S. Patent 3,8~-,942, U.S. Patent J~

204~572 4,234,644, U.S. Patent 4,419,004, U.S. Patent 4,419,005, U S. Patent 4,480,003, U.S. Patent 4,711,816, U.S. Patent 4,637,974, U.S. Patent 4,370,379, U.S. Patent 4,599,293, U.S. Patent 4,466,174, U.S. Patent 4,371,582, U.S. Patent 4,680,235, U.S. Patent 4,775,594, U.S. Patent 4,474,850, U.S. Patent 4,592,954, U.S. Patent 4,503,111, U.S. Patent 4,650,714, U.S. Patent 4,732,786, U.S. Patent 4,308,542, U.S. Patent 4,269,891, U.S. Patent 4,371,582, U.S. Patent 4,301,195, U.S. Patent 4,578,285, U.S. Patent 4,555,437, U.5. Patent 4,711,816, U.S. Patent 4,781,985, U.S. Patent 4,686,118, U.S. Patent 4,701,837, U.S. Patent 3,320,089, U.S. Patent 3,841,903; U.S. Patent 4,770,934, and U.S. Patent 4,830,91 1 .
Heat resistant coating materials are also known. For example, U.S. Patent 4,732,815 (Mizobuchi et al.~ and U.S. Patent 4,778,729 (Mizobuchi) disclose a heat transfer sheet comprising a base film and a hot melt ink layer formed on one surface of the base film, said hot melt ink layer comprising one or more components which impart filling to the printed areas of a transferable paper during transferring. Another type of heat transfer sheet comprising a base film, a hot melt ink layer laminated on one surface of the base film, and a filling layer laminated on the hot melt ink layer is also disclosed. The sheet can have a backing layer of a heat resistant antistick polymer such as silicone-modified acrylic resins, silicone-modified polyester resins, vinylidene fluoride resins, and the like.
In addition, U.S. Patent 4,875,961 (Oike et al.) discloses a heat sensitive transfer medium comprising a support and a transfer layer comprising at least a nonflowable ink layer and an adhesive layer, said two layers being provided in that order from the support side. The transfer medium can have a backing layer of a material such as a fluorine cOIli ' li"g polymer.
U.S. Patent 5,006,407 (Malllotra), issued April 19, 1991, dis~loses a ~la~ .a,t:l-cy which cc""p~;ses a l,~dr~pl-,"' A

204657~
coatin~ and a pld:,Li~ such as a pl~o~.h~ , a substituted phthalic anhydride, a ~Iycerol, a glycol, a substituted ~Iycerol, a pyrrolidinone, an alkylene carbonate, a sulfolane, or a stearic acid derivative. Papers havinJ the disclosed coatin~s are also included in the disclosure.
U.S. Patent 4,956,225 (Malhotra), issued September 11, 1990, discloses ~ "~pa,~ s suitable for r,l~,L,u~,c,ph;c and xerographic imaging which comprise a polymeric substrate with a toner receptive coating on one surface comprising blends of: poiy(ethylene oxide) and carboxymethyl cellulose; poly(ethylene oxide), carboxymethyl cellulose and hydroxypropyl cellulose; poly(ethylene oxide) and vinylidene fluoride/hexafluoropropylene copolymer, poly(chloroprene) and poly(a-methylstyrene); poly(caprolactone) and poly(a-methylstyrene);
poly(vinylisobutylether) and poly(a-methylstyrene); blends of poly(caprolactone) and poly(p-isopropyl a-methylstyrene); blends of poly(1,4-butylene adipate) and poly(a-methylstyrene); chlorinated poly(propylene) and poly(a-methylstyrene); chlorinated poly(ethylene) and poly(Q-methylstyrene); and chlorinated rubber and poly(Q-methylstyrene).
This copending application also discloses transparencies suitable for electrographic and xerographic imaging processes comprising a supporting polymeric substrate with a toner receptive coating on one surface thereof which comprises: (a) a first layer coating of a crystalline polymer selected from the group consisting of poly(chloroprene), chlorinated rubbers, blends of poly(ethylene oxide), and vinylidene fluoridelhexafluoropropylene copolymers, chlorinated poly(propylene), chlorinated poly(ethylene), poly(vinylmethyl ketone), poly(caprolactone), poly(1,4-butylene adipate), poly(vinylmethyl ether), and poly(vinyl isobutylether); and (b) a second overcoating layer comprising a cellulose ether selected from the group con .; ,li"~ of hydroxypropyl methyl cellulose, hydroxypropyl cellulose, and ethyl cellulose.
U.S. Patent 4,997,697 (Malhotra), issued March 5, 1991 discloses a Lldllspc"t"l substrate material for receiving or co" ,i"g an image which cci"~,,ises a supporting substrate base, an antistatic polymer layer coated on one or both sides of the substrate and comprising hydrophilic cellulosic co~"pol~e"L~, and a toner receiving polymer layer contained on one or both sides of the antistatic layer, which polymer coi"p~ises h~.J,~,pho~;c cellulose ethers, hydrophobic cellulose esters or mixtures thereof, and wherein the toner receiving layer contains adhesive col~ ol~
Although l~nown recordi ng sheets are suitable for thei r intended purposes, a need remains for recording sheets that do not exhibit curling and which retain their anticurl characteristics after exposure to heat.
Known recording sheets, such as the transparency sheets disclosed in, for example, U.S. Patent 4,592,954 and U.S. Patent 4,865,914, generally comprise ink receiving coatings or layers on a base sheet. Frequently, the ink receiving layer is present on the base sheet in a coating weight of, for example, from about 8.0 to about 20.0 grams per square meter, and the layer frequently is present only on one side of the base sheet. These heavy coating weights can result in curling problems with the recording sheets, particularly when the sheets are transparencies used for projection of images. One possible method of avoiding the curling problem is to coat both surfaces of the base sheet with the ink receiving layer. Recording sheets bearing ink receiving layers on both surfaces, however, can present difficulties during stacking of the sheets, wherein an ink image is transferred from the printed surface of one recording sheet to the printed or non,~"i"Lt:d surface of another recording sheet. Another possible method of avoiding curling problems is to provide a recording sheet with a two-layered anticurl back layer. Recording sheets of this configuration perform well under all humidities at 80F temperatures in printers that do not use A

heaters for fast dryin~ of the ink images. When employed in printers equipped with heaters, however, these recordin~ sheets may exhibit curling problems as a result of loss of moisture caused by the heating.
Accordingly, there is a need for recording sheets that do not exhibit curl upon exposure to a wide range of relative humidities and do not curl 5~lhse~l ~ent to being subjected to head.
SUMMARY OF THE INVFNTION
It is an object of an aspect of the present invention to provide recording sheets suitable for printing and imaging 2~F' Iions.
It is an object of an aspect of the present invention to provide recordin~ sheets that do not curl upon exposure to a wide ran~qe of relative humidities.
It is an object of an aspect of the present invention to provide recording sheets that do not curl s~hseq~ent to exposure to heat.
It is an object of an aspect of the present invention to provide recording sheets that enable the formation of hi~qh quality color ima~es thereon .
An object of an aspect of the present invention is to provide recording sheets compatible with printing p,ucesses wherein heat is applied to the recording sheet.
An object of an aspect of the present invention is to provide recording sheets that enabie the formation of ima~es of high optical density thereon.
An object of an aspect of the present invention is to provide recording sheets that can be imaged and then stacked together with little or no transfer of ima~es from one sheet to adjacent sheets.
It is an object of an aspect of the present invention to provide recording sheets for which curl is minimized or: ' " ,dled.

- - 10- 20~6572 It is an object of an aspect of the present invention to provide recording sheets which, when printed with inks of more than one color, exhibit good mixing of primary colors to generate high quality secondary colors .
It is an object of an aspect of the present invention to provide recording sheets which, when printed with inks of more than one color, exhibit little or no bleeding of colors.
An object of an aspect of the present invention is to provide recording sheets that are Su~ alli "y L~allspa~t:"l.
An object of an aspect of the present invention is to provide recording sheets that are opaque, such as coated papers, coated opaque polymeric base sheets, and the like.
An object of an aspect of the present invention is to provide recording sheets that enable the formation of suL,~Ialli "y pe""a,le, images thereon.
It is an object of an aspect of the present invention to provide recording sheets suitable for use in ink jet printing process.
It is an object of an aspect of the present invention to provide recording sheets suitable for use in elecrophulu~,dplli~, ionographic, and electrographic imaging process.
It is an object of an aspect of the present invention to provide recording sheets that avoid or minimize jamming when fed along the paper path of a printing or imaging device, particularly at fuser rolls in eleul,opllolùgraphic, ionographic, or el~ ,u~,aphic ima~qing devices.
These and other objects of the present invention (or specific en ho~' "e"l~ thereof) can be achieved by providing a recording sheet which ~o",,urises, in the order stated, an ink receiving layer, a base sheet, a heat absorbing layer, and an anticurl layer. Another embodiment of the present invention is directed to a recording sheet - 10a-which c~",p,i~as, in the order stated, an ink receiving layer, a first heat absorbing layer, a base sheet, a second heat absorbing layer, and an anticurl layer. Yet another ~,IIL "e"~ of the present invention is directed to a process which COlllp(i:~5 applying a recording liquid to a recording sheet of the present inventio~ in an illlag~ir~;~G pattern.
Still another embodiment of the present invention is directed to a printing process which cor"J,is~ (1) illCOI,lJ~:>ldlill9 into an ink jet printing apparatus Golli ' ~' ~9 an ink a recording sheet of the present invention and causing droplets of the ink to ~ - 1 1 -~04~
be ejected in an imagewise pattern onto the recording sheet, thereby generating images on the recording sheet. Another embodiment of the present invention is directed to a process for generating images which comprises generating an electrostatic latent image on an imaging member in an imaging apparatus, developing the latent image with a toner, transferring the developed image to a recording sheet of the present invention, and optionally permanently affixing the transferred image to the recording sheet Yet another embodiment of the present invention is directed to an imaging process which comprises generating an electrostatic latent image on a recording sheet of the present invention, developing the latent image with a toner, and optionally permanently affixing the developed image to the recording sheet.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 illustrates schematically in cross section one embodiment of the recording sheet of the present invention comprising a base sheet having an ink receptive layer on one surface and a heat absorbing layer and an anticurl layer on the other surface.
Figure 2 illustrates schematically in cross section another embodiment of the recording sheet of the present invention comprising a base sheet having a heat absorbing layer and an ink receptive layer on one surface and a heat absorbing layer and an anticurl layer on the other su rface.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Illustrated schematically in Figure 1 is one embodiment of the recording sheet of the present invention which comprises a base sheet 11 with an ink receiving layer 15 on one surface and, on the other surface, a heat absorbing layer 17 in contact with base sheet 11 and an anticurl layer 19 coated onto heat absorbing layer 17.
Illustrated schematically in Figure 2 is another e,~,bo.l;",e"~ of the recording sheet of the present invention which comprises a base sheet 21 coated on one surface with a first heat absorbing layer 23. First heat ~ -t2- 2~ 72 absorbing layer 23 is coated with ink receiving layer 25. The opposite surface of base sheet ~1 is coated with second heat absorbing layer 27, and second heat absorbing layer 27 is coated with an anticurl layer 29.
The base sheet for the recording sheets of the present invention can be any suitable material for receiving images. Examples include transparent materials, such as polyester, including MylarTY, available from E.l. Du Pont de Nemours & Company, Melinex7U, available from Imperial Chemicals, Inc, Celanar7Y, available from Celanese Corporation, polycarbonates such as LexanTU, available from General Electric Company, polysulfones, cellulose triacetate, polyvinylchloride cellophane, polyvinyl fluoride, and the like, with polyester such as MylarTY being preferred in view of its availability and relatively low cost. The base sheet can also be opaque, such as paper, including plain papers such as Xerox~ 4û24, diazo papers, or the like, or opaque plastics and filled polymers, such as Melinex'~, available from ICI. The base sheet can be of any effective thickness. Typical thicknesses for the base sheet are from about 50 to about 125 microns, and preferably from about 100 to about 125 microns.
The ink receiving layer or layers of the recording sheets of the present invention are selected to be compatible with the material from which images will be formed on the recording sheet. For example, when the recording sheet is intended for use in ink jet printing processes, the ink receiving layer or layers are of a material that will enable formation of high quality images with the ink used in the process, which typically is an aqueous based ink. When the recording sheet is intended for use in electrophotographic, ionographic, or electrographic printing processes, the ink receiving layer or layers are of a material compatible with the toner employed to develop the images, which may be either a dry toner or a liquid toner, and which typically is hydrophobic. Examples of coating materials suitable for recording sheets for printing processes employing aqueous based inks include hydrophilic materials, such as binary blends co~prising poly(ethylene oxide), such as POLYOXT~ W5RN-3000, available from Union Carbide Company, preferably in an amount of from about 10 to about 90 percent by weight, and a component, pl~r~relbly in an amount of 2~ 7~
from about 10 to about 90 percent by weight, selected from the group consisting of: (1) hydroxypropyl methyl cellulose, such as Methocelr"
K35LV, available from Dow Chemical Company; (2) vinylmethyl ether/maleic acid copolymers, such as Gantrez'~ 5-95, available from GAF
Corporation; (3) acrylamide/acrylic acid copolymers, available from Scientific Polymer Products; (4) salts of carboxymethylhydroxyethyl cellulose, such as sodium carboxymethylhydroxyethyl cellulose, such as CMHEC43H'~ and 37LT~, available from Hercules Chemical Company (CMHEC 43HT~ j5 believed to be a high molecular weight polymer with carboxymethyl cellulose (CMC/hydroxyethyl cellulose (HEC) ratio of 4:3, CMHEC 37LTU is believed to be a low molecular weight polymer with CMC/HEC ratio of 3:7); (5) hydroxyethyl cellulose, such as Natrosol 250LR, available from Hercuies; (6) water soluble ethylhydroxyethyl cellulose, such as BermocollT~, available from Berol Kem, AB, Sweden; (7) cellulose sulfate, available from Scientific Polymer Products; (8) poly(vinyl alcohol), available from Scientific Polymer Products; (9) poly(vinyl pyrrolidone), available from GAF Corporation; (10) hydroxybutylmethyl cellulose, available from Dow Chemical Company; (11) hydroxypropyl cellulose, such as Klucelr~ Type E, available from Hercules; (12) poly(2-acrylamido-2-methyl propane sulfonic acid, available from 5cientific Polymer Products); (13) methyl cellulose, available from Dow Chemical Company; (14) hydroxyethylmethyl cellulose, such as HEM, available from British Celanese Ltd., and Tylose MH, MHK
from Kalle A.G.; (15) cellulose acetate, available from Scientific Polymer Products; (16) cellulose acetate hydrogen phthalate, such as CAP, available from Eastman Kodak Company; (17) hydroxypropylmethyl cellulose phthalate, such as HPMCP, available from Shin-Etsu Chemical; (18) vinylalcohol/vinylacetate copolymers, available from Scientific Polymer Products; (19) vinylalcohol/vinylbutyral copolymers, available from Scientific Polymer Products; (20) salts of carboxymethyl cellulose, such as sodium ~drLoxy",~ yl cellulose, such as CMC Type 7HOF, available from Hercules Chemical Company; and (21) vinyl pyrrolidone/vinyl acetate copolymers, available from Scientific Polymer Products. Also suitable are ternaryblendscomprisingpoly(ethyleneoxide),p~ere,ablyinanamountof 2~ 7~
from about 1û to about 50 percent by weight, salts of carboxymethyl cellulose, such as sodium carboxymethyl celluiose, preferably in an amount of from about 5 to about 85 percent by weight, and a component, pr~r~rdbly in an amount of from about 5 to about 45 percent by weight, selected from the group consisting of (1) hydroxypropyl methyl cellulose, such as MethocelT`' K35LV, available from Dow Chemical Company; (2) vinylmethyl ether/maleic acid copolymers, such as GantrezTU S-95, available from GAF Corporation; (3) acrylamide/acrylic acid copolymers, available from Scientific Polymer Products; (4) salts of carboxymethylhydroxyethyl cellulose, such as sodium carboxymethylhydroxyethyl cellulose, such as CMHEC43HT~, 37L, available from Hercules Chemical Company; (5) hydroxyethyl cellulose, such as Natrosoll~ 250LR, available from Hercules;

(6) water soluble ethylhydroxyethyl cellulose, such as BermocollTU, available from Berol Kem, AB, Sweden; (7) cellulose sulfate, available from Scientific Polymer Products; (8) poly(vinyl alcohol), available from Scientific Polymer Products; (9) poly(vinyl pyrrolidone), available from GAF Corporation; (10) hydroxybr~lyll"~ yl cellulose, available from Dow Chemical Company; (11) hydroxypropyl cellulose, such as KlucelT" Type E, availabie from Hercules;
(12) poly(2-acrylamido-2-methyl propane sulfonic acid), available from Scientific Polymer Products; (13) methyl cellulose, available from Dow Chemical Company; (14) hydroxyethylmethyl cellulose, such as HEM
available from British Celanese Ltd., and TyloseT" MH, MHK from Kalle A G.;
(15) poly(diethylene triamine-co-adipic acid), available from Scientific Polymer Products; (16) poly(imidazoline) quaternized, available from Scientific Polymer Products; (17) poly(ethylene imine) epichlorohydrin modified, available from Scientific Polymer Products; (18) poly(N,N
dimethyl-3, 5-dimethylene piperidinium chloride), available from Scientific Polymer Products; and (19) poly(ethylene imine) ethoxylated, available from Scientific Polymer Products. Also suitable are ternary blends of poly(ethylene oxide), preferably in an amount of from about 10 to about 50 percent by weight, hydroxyalkylmethyl cellulose (wherein the alkyl group generally has from 1 to about 1û carbon atoms, such as ethyl, propyl or butyl), preferably in an amount of fronn about 5 to about 85 percent by 2~4~72 weight, and a component, preferably in an amount of from about 5 to about 45 percent by weight, selected from the group consisting of (1) hydroxypropyl cellulose, such as KlucelTY Type E, available from Hercules;
(2) vinylmethyl ether/maleic acid copolymers, such as Gantrez~H S-95, available from GAF Corporation; (3) acrylamide/acrylic acid copolymers, available from Scientific Polymer Products, (4) salts of carboxymethylhydroxyethyl cellulose, such as sodium carboxymethylhydroxyethyl cellulose, such as CMHEC43HTY, 37L, available from Hercules Chemical Company; (5) hydroxyethyl cellulose, such as Natrosol 250LR, available from Hercules Chemical Company; (6) water soluble ethylhydroxyethyl cellulose, such as BermocollTY, available from Berol l<em, AB, Sweden; (7) cellulose sulfate, available from Scientific Polymer Products; (8) poly(vinyl alcohol), available from Scientific Polymer Products; (9) poly(vinyl pyrrolidone), available from GAF Corporation; (10) poly(2-acrylamido-2-methyl propane sulfonic acid), available from Scientific Polymer Products; (11) methyl cellulose, available from Dow Chemical Company; (12) salts of carboxymethyl cellulose, such as sodium carboxymethyl cellulose, such as CMC 7HOFTH, available from Hercules Chemical Company; (13) poly(diethylene triamine-co-adipic acid), available from Scientific Polymer Products; (14) poly(imidazoline) quaternized, available from Scientific Polymer Pro~ucts; (15) poly(ethylene imine) epichlorohydrin modified, available from Scientific Polymer Products; (16) poly(N,N-dimethyl-3,5-dimethylene piperidinium chloride), available from Scientific Polymer Products; and (17) poly(ethylene imine) ethoxylated, available from Scientific Polymer Products.
Illustrative specific examples of binary (two polymers) and ternary (three polymers) blends suitable as ink receiving layers for printing processes employing aqueous based inks include binary blends of hydroxyethylmethyl cellulose, 75 percent by weight, and poly(ethylene oxide), 25 percent by weight; binary blends of hydroxypropylmethyl cellulose, 80 percent by weight, and poly(ethylene oxide), 20 percent by weight; binary blends of hydroxybutylmethyl cellulose, 70 percent by weight, and poly(ethylene oxide), 30 percent by weight; binary blends of ~ 2046572 sodium carboxymethyl cellulose, 80 per~ent by weight, and poly(ethylene oxide), 20 percent by weight; ternary blends of hydroxyalkylmethyl cellulose, 50 percent by weight, sodium carboxymethyl cellulose, 25 percent by weight, and poly(ethylene oxide), 25 percent by weight; ternary blends of hydroxyalkylmethyl cellulose, 60 percent by weight, poly(ethylene oxide), 20 percent by weight, and poly(N,N-dimethyl-3,5-dimethylene piperidinium chloride), 20 percent by weight; and ternary blends of hydroxypropylmethyl cellulose, 50 percent by weight, poly(ethylene oxide), 25 percent by weight, and sodium carboxymethyl cellulose, 25 percent by weight, and the like. Binary blends of hydroxypropylmethyl cellulose, 80 percent by weight, and poly(ethylene oxide), 20 percent by weight, are preferred in some embodiments as these yield images of high optical density (when, for example imaged in Xerox~ 4020~ ink jet printers), such as 1.15 (black), 1.44 (magenta), 0.84 (cyan) and 0.57 (yellow), which images are resistant to humidity, for example between 20 to 80 percent humidity at 80~F. Further examples of coating materials compatible with aqueous based inks are disclosed in, for example, U.S. Patent 4,528,242, U.S Patent 4,547,405, U.S. Patent 4,555,437, U.S. Patent 4,575,465, U.S. Patent 4,578,285, U.S. Patent 4,592,954, U.5. Patent 4,649,064, U.5. Patent 4,781,985, U.S. Patent 4,887,097, U.S. Patent 4,474,850, U.S. Patent 4,650,714, U.S. Patent 4,732,786, U.S. Patent 4,775,594, U.5. Patent 4,308,542, U.S. Patent 4,269,891, U.5. Patent 4,371,582,U.S. Patent 4,301,195, U.S. Patent 4,503,111, U.S. Patent 4,686,118, U.S. Patent 4,701,837, U.S. Patent 4,770,934, U.S. Patent 4,466,174, U.S. Patent 4,371,582, U.5. Patent 4,680,235, U.S. Patent 4,711,816, and U.S. Patent 4,830,91 1 .
Examples of coating materials suitable for recording sheets for electrophotographic, ionographic, or electrographic imaging processes employing dry or liquid toners include hydrophobic materials, such as blends of poly(Q-methyl styrene) (molecular weight M between 103 and 105, available from Amoco as resin 18-290), preferably in an amount of from about 5 to about 95 percent by weight, and a component, preferably ~ -17-~ 72 in an amount of from about 5 to about 95 percent by weight, selected from the group consisting of (1) poly(ethylene oxide), such as POLY OX-WSRN7"
3000, available from Union Carbide Company; (2) halogenated (such as chlorinated, brominated, fluorinated, iodated, or the like) rubber, such as a rubber with a chlorine content of about 65 percent, available from Scientific Polymer Products; (3) halogenated (such as chlorinated, brominated, fluorinated, iodated, or the like) poly(propylene), such as a polypropylene with a chlorine content of about 65 percent by weight, available from Scientific Polymer Products; (4) halogenated (such as chlorinated, brominated, fluorinated, iodated, or the like) poly(ethylene), such as a polyethylene with a chlorine content of about 48 percent by weight, available from Scientific Polymer Products; (5) poly(caprolactone), such as pLC 700'U, available from Union Carbide Company; (6) poly(chloroprene), available from Scientific Polymer Products; (7) poly(1,4-butylene adipate), available from Scientific Polymer Products; (8) poly(vinylmethylether), such as LutonalTY M-40, available from BASF; (9) poly(vinylisobutylether), such as Lutonal~ 160, available from BASF; (10) styrene-butadiene copolymers, such as KratonTU 1102 and Kraton'~ 1652, available from Shell Company; and (11) ethyl cellulose, such as EthocelT~
Type-i~l, available from Hercules Chemical Company. Specific examples of binary blends suitable as toner or ink receiving layer materials for electrophotographic, ionographic, or electrographic imaging include blends of poly(a-methyl styrene) in an amount of about 80 percent by weight and poly(chloroprene) in an amount of about 20 percent by weight;
blends of chlorinated rubber in an amount of about 80 percent by weight and poly(a-methyl styrene) in an amount of about 20 percent by weight;
blends of poly(a-methyl styrene) in an amount of about 20 percent by weigh~and styrene-butadiene copolymer in an amountof about80 percent by weight; and blends of poly(a-methyl styrene) in an amount of about 20 percent by weight and ethyl cellulose in an amount of about 80 percent by weight. Blends of poly(a-~nethyl styrene) with chloroprene or ethyl cellulose or chlorinated rubber are often preferred, as recording sheets coated with these polymers and imaged with a Xerox~ 10051Y color copier -~8-~ ~ 2046572 yie~d high optical density images of, for example, 1.6 (black), 1.40 (magenta), 1.50 (cyan), and 0.80 (yellow), which could not be lifted off with 3M scotch tape 60 seconds subsequent to their preparation. Further examples of coating materials compatible with dry and liquid toners are disclosed in, for example, U.S. Patent 3,320,089, U.S. Patent 3,488,189, U.S.
Patent 3,493,412, U.S. Patent 3,535,112, U.S. Patent 3,539,340, U.S. Patent 3,539,341, U.S. Patent 3,619,279, U.S. Patent 3,833,293, U.S. Patent 3,841,903, U.S. Patent 3,854,942, U.5. Patent 4,071,362, U.S. Patent 4,085,245, U.S. Patent 4,234,644, U.S. Patent 4,259,422, U.5. Patent 4,370,379, U.S. Patent 4,419,004, U.S. Patent 4,419,005, U.S. Patent 4,480,003, U.S. Patent 4,489,122, U.S. Patent 4,526,847, and U.S. Patent 4,599,293.
The ink receiving layer or layers can be of any effective thickness.
Typical thicknesses are from about 1 to about 25 microns, and preferably from about 5 to about 15 microns. In addition, the ink receiving layer can optionally contain filler materials, such as inorganic oxides, including silicondioxide, titanium dioxide (rutile), and the like, colloidal silicas, such as Syloid'~ 74 available from W.R. Grace & Company, calcium carbonate, or the like, as well as mixtures thereof, in any effective amount. Typical amounts of fillers are from about 1 to about 25 percent by weight of the coating composition, and preferably from about 2 to about 10 percent by weight of the coating composition. When it is desired that the recording sheet of the present invention be transparent, the filler typically is present in an amount of up to about 3 percent by weight. Filler components may be useful as a slip component for feeding the recording sheet through a printing or imaging apparatus, since addition of the filler renders the sheet surface discontinuous, thereby imparting roughness to the surface and making it easy to grip in a machine equipped with pinch rollers. In addition, fillers such as silica can enhance color mixing when primary colors are mixed to form secondary colors, particularly in ink jet printing processes.

2~ 7~
The heat absorbing layer or layers of the recording sheets of the present invention is of a material capable of absorbing or dissipating heat applied to the recording sheet. Specific examples of materials suitable for the recording sheets of the present invention include: (1) vinylidene fluoride/hexafluoropropylene copolymels, such as VitonrU E-45, available from E.~. Du Pont de Nemours & Company, or Fluorel7U, available from 3M
Company; (2) vinylidene fluoride/hexafluoro propylene/tetrafluoroethylene copolymers, such as VitonTY B, available from E.l Du Pont de Nemours 13 Company; (3) vinylidene fluoride/tetrafluoroethylene/perfluoro methylvinyl ether terpolymers, such as VitonTU GLT and KalrezTU, available from E.l. Du Pont de Nemours &
Company; (4) tetrafluoro propylene/propylene copolymers, such as AftalTU, available from Asahi Glass Company; (5) vinylidene fluoride/chloro trifluoroethylene copolymers, such as Kel-FTU, available from 3M Company;
(6) tetrafluoroethylene/ethylene copolymers, such as Tefzel-200TU and HT-2004T~ available from E.l. Du Pont de Nemours & Company; (7) tetrafluoroethylene/hexafluoropropylene copolymers, such as TeflonTU
FEP-140, available from E.l. Du Pont de Nemours & Company; (8) poly(vinyl f~uoride), such as TedlarTU resin and Tedlar'Y PVF film, available from E.l. Du Pont de Nemours & Company (9) poly(vinylidene fluoride), such as Kynar'~, available from Pennwalt Corporation; (10) styrene-b-isoprene-b-dimethylsiloxane triblock copolymers, preferably with a styrene content of about 50 percent by weight, isoprene content of about 30 percent by weight and dimethylsiloxane content of about 20 percent by weight (s~"~ si~ed via sequential addition anionic polymerization of styrene with n-butyl lithium and initiator followed by addition of isoprene and octamethyl cycl~ Lla~ilo~dne, and quenching the reaction with methanol);
(11) dimethyl siloxane-b-bisphenol A carbonate diblock copolymers, such as #789, available from Scientific Polymer Products; (12) dimethylsiloxane-b-a-methyl styrene diblock copolymers, such as #790, available from Scientific Polymer Products; (13) poly(sulfone), such as #046, available from Scientific Polymer Products; (14) poly(sulfide), such as #588, available from Scientific Polymer Products; (15) chlorosulfonated poly(ethylene), such as #1û7, ~ 4~57~
availabie from Scientific Polymer Products; (16) acrylonitrile/butadiene copolymers, such as #055, available from Scientific Polymer Products; (17) acrylonitrile/butadiene/styrene terpolymers, such as #051, available from Scientific Polymer Products; (18) styrene/butadiene copolymers, such as KratonTU 1102 and KratonT~ 1652, available from Shell Company, (19) styrene/isoprene diblock copolymers, preferably with a molecular weight of about 1.0 x 105 and preferably with a styrene content of about 50 percent by weight (synthesized via anionic sequential addition polymerization of styrene followed by addition of isoprene, n-butyl lithium being the initiator and methanol as the terminator); (20) isobutylene/isoprene halogenated (such as brominated, chlorinated, or the like) copolymers, such as #649, available from Scientlfic Polymer Products; (21) ethylene/propylene rubber, such as #358, available from Scientific Polymer Products; (22) ethylene/ethylacrylate copolymers, such as #455, available from Scientific Polymer Products; (23) ethylene/propylene/diene terpolymers, such as #359, available from Scientific Polymer Products; (24) ethylene/vinyl acetate copolymers, such as #786, available from Scientific Polymer Products; and (25) ethylene/maleic anhydride copolymers, such as #197, available from Scientific Polymer Products.
Specific examples of heat absorbing or dissipating materials include fluorine containing polymers such as vinylidene fluoride/hexafluoropropylene copolymers with from about 10 to about 40 percent by weight of hexafluoropropylene;
tetrafluoroethylene/hexafluoropropylene random copolymers with from about 10 to about 50 percent by weight of hexafluoropropylene;
vinylidene fluoride/hexafluoro propylene/tetrafluoroethylene terpolymers with from about 10 to about 60 percent by weight of hexafluoro propylene, from about 40 to about 10 percent by weight of vinylidene fluoricle, and from about 30 to about 50 percent by weight of tetrafluoroethylene; vinylidene fluoride/hexafluoro propylene/tetrafluoroethylene terpolymers with from about 10 to about 60 percent by weight of hexafluoro propylene, from about 10 to about 40 percent by weight of vinylidene fluoride, and from about 30 to about 50 ~ -21- 20~72 percent by weight of tetrafluoroethylene; vinylidene fluorideltetrafluoroethylene/perfluoromethyl vinyl ether terpolymers with from about 10 to about 60 percent by weight of vinylidene fluoride, from about 30 to about 50 percent by weight of tetrafluoroethylene, and from about 10 to about 40 percent by weight of perfluoromethylvinyl ether;
tetrafluoroethylenelpropylene copolymers with a propylene content of from about 10 to about 60 percent by weight; vinylidene fluoridelchlorotrifluoroethylene copolymers with a vinylidene fluoride content of from about 10 to about 60 percent by weight;
tetrafluoroethylene/ethylene copolymers with an ethylene content of from about 20 to about 70 percent by weight; poly(vinylidene fluoride);
poly(vinyl fluoride); siloxane containing polymers such as styrene-b-isoprene-b-dimethylsiloxane triblock copolymers with a styrene content of from about 10 to about 70 percent by weight, an isoprene content of from about 20 to about 50 percent by weight, and a dimethylsiloxane content of from about 10 to about 40 percent by weight; dimethylsiloxane-b-bisphenol A carbonate diblock copolymers with a dimethylsiloxane content of from about 10 to about 70 percent by weight; dimethylsiloxane-b-a methylstyrene diblock copolymers with a dimethylsiloxane content of from about 10 to about 70 percent by weight; sulfur containing polymers such as poly(sulfone); polysulfide rubber (which is a terpolymer of bis(2 chloroethyl) formallsodium sulfidel1,2,3-trichloro propane);
chlorosulfonated poly(ethylene); diene containing polymers such as acrylonitrilelbutadiene copolymers with an acrylonitrile content of from about 15 to about 60 percent by weight; acrylonitrilelbutadienelstyrene terpolymers with an acrylonitrile content of from about 15 to about 60 percent by weight, a butadiene content of from about 10 to about 65 percent by weight, and a styrene content of from about 20 to about 30 percent by weight; styrenelbutadiene copolymers with a styrene content of from about 10 to about 90 percent by weight; styrenelisoprene copolymers with a styrene content of from about 1û to about 90 percent by weight;
isobutylenc,';,opr~,~e brominated with an isoprene content of about 1.5 percent by weight and a bromine content of 2.1 percent by weight; alkene 2a46.~,~2 containing polymers such as ethylene/propylene rubber with an ethylene content of from about 2û to about 6û percent by weight;
ethylene/ethylacrylate copolymers with an ethylene content of from about 25 to about 85 percent by weight; ethylenelpropylene/diene copolymers with an ethylene content of from about 2û to about 7û percent by weight, a diene content of from about 3 to about 20 percent by weight, and a propylene content of from about 10 to about 77 percent by weight;
ethylene/vinylacetate copolymers with an ethylene content of from about 25 to about 95 percent by weight; and ethylene/maleic anhydride copolymers with an ethylene content of from about 25 to about 75 percent by weight. Additional examples of heat absorbing materials are disclosed in, for example, U.S. Patent 4,832,815, U.S. Patent 4,778,729, and U.S.
Patent 4,875,961. Mixtures of two or more heat absorbin~ or dissipatin~ materials can also be employed.
The heat absorbing layer or layers are of any effective thickness.
Typical thicknesses are from about 1 to about 25 microns, and preferably from about 2 to about 15 microns when one heat absorbing layer is present between the base sheet and the anticurl layer. When two heat absorbing layers are present, one between the base sheet and the anticurl layer and the other between the base sheet and the ink receiving layer or layers, typical thicknesses are from about 1 to about 25 microns, and preferably from about 2 to about 15 microns for the heat absorbing layer situated between the base sheet and the anticurl layer, and from about 1 to about 10 microns, and preferably from about 2 to about 5 microns for the heat absorbing layer situated between the base sheet and the ink receiving layer or layers.
The anticurl layer is of a material that reduces or eliminates curli~g of the recording sheet of the present invention, even when it is exposed to a wide range of relative humidities. Examples of suitable materials for the anticurl layer include hydrophilic materials, such as (1) hydroxypropylmethyl cellulose, such as Methocel'" K35 LV, available from Dow Chemical Company; (2) hydroxybutylmethyl cellulose, available from 2Q~7?
Dow Chemical Company; (3) hydroxyethylmethyl celluiose, such as HEM'~, available from British Celanese Ltd., and Tylose MH, MHK available from Kalle A-G; ~4) hydroxyethyl cellulose, such as Natrosol 25ûLR, available from Hercules Chemical Company; (5) ethylhydroxyethyl celiulose, such as Bermocoll, available from 8erol Kem, AB, Sweden; (6) salts of carboxyrnethyl cellulose, such as sodium carboxymethyl cellulose, such as CMC 7HOF, available from Hercules Chemical Company; (7) salts of carboxymethyl hydroxyethyl cellulose, such as sodium carboxymethyl hydroxyethyl cellulose, such as CMHEC 43H, 37L, available from Hercules Chemical Company; (8) methyl cellulose, such as Methocel-A, available from Dow Chemical Company; (9) poly(acrylamide) polymers, available from Scientific Polymer Products; (1û) cellulose sulfate, available from Scientific Polymer Products; (11) hydroxyalkylmethyl cellulose (wherein the alkyl group generally has from 1 to about 10 ~arbon atoms, such as ethyl, propyl or butyl); (12) acrylamide-acrylic acid copolymers; and the like.
Mixtures of two or more anticurl materials can also be used. The anticurl layer is of any effective thickness. Typical Illickl,esses are from about 1 to about 25 microns, pler~rdbl~ from about 2 to about 15 microns.
r,~ r~,c,bl~, the total combined thickness of both the anticurl layer and the heat absorbin~ layer situated between the base sheet and the anticurl layer is from about 2 to about 50 microns, and more preferably from about 5 to about 25 microns.
The recording sheets of the present invention can be prepared by any suitable method. For example, the layer coatings can be applied by a number of known techniques, including melt extrusion, reverse roll, solvent extrusion, and dip coating processes. In dip coating, a web of material to be coated is transported below the surface of the coating material by a single roll in such a manner that the exposed site is saturated, followed by the removal of any excess coating by a blade, bar, or squeeze roll; the process is then repeated with the appropriate coating materials for A

2~46~72 application of the other layered ~oatings. With reverse roll coating, the pr~",~le~d coating material is transferred from a steel applicator roll onto the web material to be coated. The metering roll is stationary or is rotating slowly in the direction opposite to that of the applicator roll. In slot extrusion coating, a flat die is used to apply coating materials with the die lips in close proximity to the web of material to be coated. Once the desired amount of coating has been appiied to the web, the coating is dried at 25 to 100C in an air drier. In melt extrusion, an extruder converts solid pellets or powder of thermoplastic resin into a uniform bubble-free melt at the required temperature, and this melt is extruded through a flat die vertically downward into the nip of the coating rolls where it is deposited on the web of the material to be coated in the form of a film. After cooling, the film is laminated to the web material. An extrusion coater can be used to prepare recording sheets of the present invention by coating a polyester base sheet with fluoro polymers that are not soluble in common solvents.
A specific example of a process for preparing a recording sheet of the present invention entails providing a base sheet such as Mylar7Y (in roll form) in a thickness of from about 100 to about 125 microns and applying to one side of the MylarrU by a solvent extrusion process on a Faustel coater in a thickness of about 2 to about 25 microns a heat dissipating vinylidene fluoride/hexafluoro propylene copolymer, which copolymer is present in a concentration of about 5 percent by weight in a solvent such as acetone. Thereafter, the coating is air dried at about 60C
and the resulting polymer layer is then overcoated on the Faustel coater with a hydrophilic layer in a thickness of about 1 to about 25 microns of, for example, hydroxypropylmethyl cellulose present in a concentration of 4 percent by weight in a mixture of water (75 percent by weight) and methanol (25 percent by weight). Subsequent to air drying at a temperature of about 1 00C, an anticurl two-layered coating on one side of the two-sided base sheet is obtained. After rewinding the coated side of the Mylar~Y on an empty core, the uncoated side of the Mylar7Y j5 coated in a thickness of from about 2 to about 25 microns with an ink receiving -25- ~4~5~2 hydrophilic coating layer such as a blend of hydroxypropylmethyl cellulose, 80 percent by weight, and poly(ethylene oxide), 20 percent by weight, which blend is present in a concentration of about 3 percent by weight in water. Thereafter, the coating is air dried and the resulting transparency can be used in apparatuses such as heat assisted color ink jet printers and the like as indicated herein Other recording sheets of the present invention can be prepared in a similar or equivalent manner.
Another specific example of a process for preparing a recording sheet of the present invention entails providing a MylarlU base sheet (in roll form) in a thickness of from 100 to 125 microns and applying to one side of the MylarTY by the known solvent extrusion process on a Faustel coater, in a thickness of from about 2 to about 25 microns a dimethyl siloxane-b-bisphenol A carbonate copolymer, which copolymer is present in a co~centration of about 2 percent by weight in dichloromethane.
Thereafter, the coating is air dried at about 100C and the resulting polymer layer is overcoated with sodium carboxymethyl cellulose (in a thickness of from about 1 to about 25 microns) present in a concentration of about 2 percent by weight in water. Subsequent to air drying at about 100C, an anticurl two-layered coating is obtained on one surface of the MylarTY. Rewinding the coated side onto an empty core and using this roll, the uncoated side of the Mylar'Y roll is coated, in a thickness of from about 2 to about 25 microns, with a hydrophobic ink receiving layer blend of chlorinated rubber, 80 percent by weigl~t, and poly(a -methyl styrene), 20 percent by weight, which blend is present in a concentration of about 3 percent by weight in toluene. Thereafter, the coating is air dried at about 100C and the resulting transparency can be utilized in a xerographic imaging apparatus, such as those available commercially as the Xerox~
1005"', and images can be obtained with optical density values of, for example, 1.6 (black), 0.85 (yellow), 1.45 (magenta), and 1.45 (cyan). Other recording sheets of the present inventi3n can be prepared in a similar or equivalent manner.
The present invention also includes printing and imaging processes with recording sheets of the present invention. One embod iment 204657?
of the present invention is directed to a process for generating images which comprises generating an electrostatic latent image on an imaging member in an imaging apparatus, developing the latent image with a toner, l~d~r~r, i"g the developed image to a recording sheet of the present invention, and optionally permanently affixing the transferred image to the recording sheet. The electrostatic latent image can be created on a photosensitive imaging member by the well known electrophotographic process, as described in, for example, U.S. Patent 2,297,691 to Chester Carlson. In addition, the electrostatic latent image can be created on a dielectric imaging member by an ionographic process, which entails applying a charge pattern imagewise to an imaging member, developing the image with a toner, and transferring the developed image to a recording sheet. Further, the recording sheet of the present invention can be employed in electrographic printing processes, which entail generating an electrostatic latent image on a recording sheet of the present invention, developing the latent image with a toner, and optionally permanently affixing the developed image to the recording sheet. Ionographic and electrographic processes are well known, and are described in, for example, U.S. Patent 3,564,556, U.S. Patent 3,611,419, U.S. Patent 4,240,084, U.S.
Patent 4,569,584, U.S. Patent 2,919,171, U.S. Patent 4,524,371, U.S. Patent 4,619,515, U.S. Patent 4,463,363, U.S. Patent 4,254,424, U.S. Patent 4,538,163, U.S. Patent 4,409,604, U.S. Patent 4,408,214, U.S. Patent 4,365,549, U S. Patent 4,267,556, U.S. Patent 4,160,257, and U.S. Patent 4, 1 55,093.
The recording sheets of the present invention can also be employed in ink jet printing processes. Generally, this embodiment of the present invention is directed to a printing process which comprises (1) incorporating into an ink jet printing apparatus containing an ink a recording sheet of the present invention and causing droplets of the ink to be ejected in an imagewise pattern onto the recording sheet, thereby generating images on the recording sheet. Ink jet printing systems generally are of two types: continuous stream and drop-on-demand. In .. ~

-27- 20~6~
continuous stream ink jet systems, ink is emitted in a continuous stream under pressure through at least one orifice or nozzle. The stream is perturbed, causing it to break up into droplets at a fixed distance from the orifice. At the break-up point, the droplets are charged in accordance with digital data signals and passed through an electrostatic field which adjusts the trajectory of each droplet in order to direct it to a gutter for recirculation or a specific location on a recording medium. In drop-on-demand systems, a droplet is expelled from an orifice directly to a position on a recording medium in accordance with digital data signals. A droplet is not formed or expelled unless it is to be placed on the recording medium.
One type of drop-on-demand system has as its major components an ink filled channel or passageway having a nozzle on one end and a piezoelectric transducer near the other end to produce pressure pulses Another type of drop-on-demand system is known as thermal ink jet, or bubble jet, and produces high velocity droplets and allows very close spacing of nozzles. The major components of this type of drop-on-demand system are an ink filled channel having a nozzle on one end and a heat generating resistor near the nozzle. Printing signals representing digital information originate an electric current pulse in a resistive layer within each ink passageway near the orifice or nozzle, causing the ink in the immediate vicinity to evaporate almost instantaneously and create a bubble. The ink at the orifice is forced out as a propelled droplet as the bubble expands. When the hydrodynamic motion of the ink stops, the process is ready to start all over again.
The operating sequence of the bubble jet system begins with a current pulse through the resistive layer in the ink filled channel, the resistive layer being in close proximity to the orifice or nozzle for that channel. Heat is transferred from the resistor to the ink. The ink becomes superheated far above its normal boiling point, and for water based ink, finally reaches the critical ~ e,dlure for bubble formation or nucleation of around 280C. Once nucleated, the bubble or water vapor thermally isolates the ink from the heater and no further heat can be applied to the ink. This bubble expands until all the heat stored in the ink in excess of the normal boiling point diffuses away or is used to ~onvert liquid to vapor, which removes heat due to heat of vaporization. The expansion of the bubble forces a droplet of ink out of the nozzle, and once the excess heat is removed, the bubble collapses on the resistor. At this point, the resistor is no longer being heated because the current pulse has passed and, concurrently with the bubble collapse, the droplet is propelled at a high rate of speed in a direction towards a recording sheet. The resistive layer encounters a severe cavitational force by the collapse of the bubble, which tends to erode it. Subsequentiy, the ink channel refills by capillary action.
This entire bubble formation and collapse sequence occurs in about 1û
microseconds. The channel can be refired after 1ûO to 500 microseconds minimum dwell time to enable the channel to be refilled and to enable the dynamic refilling factors to become somewhat dampened. Thermal ink jet processes are well known and are described in, for example, U.S. Patent 4,601,777, U.S. Patent 4,2S1,824, U.S. Patent 4,410,899, U.S. Patent 4,412,224, and U.S. Patent 4,532,530.
The recording sheets can be used in any other printing or imaging process, such as printing with pen plotters, handwriting with ink pens (either aqueous or nonaqueous based inks), offset printing processes, or the li ke, provided that the i nk employed to form the i mage is compati ble with the material selec~ed as the ink receiving layer of the recording sheet.
Generally, the term "curl" refers to the distance between the base line of the arc formed by recording sheet when viewed in cross-section across its width (or shorter dimension - for example, 8.5 inches in an 8.5 x 11 inch sheet, as opposed to length, or longer dimension - for example, 11 inches in an 8.5 x 11 inch sheet) and the midpoint of the arc. To measure curi, a sheet can be held with the thumb and forefinger in the middle of one of the long edges of the sheet (for example, in the middle of one of the 11 inch edges in an 8.5 x 11 inch sheet) and the arc formed by the sheet can be matched against a pre-drawn standard template curve ranging from zero (flat) to 65 millimeters or more (highly curled). The recording sheets of the present invention generally exhibit curl values of from 0 to about 1û
A

29- ~046~Z
millimeters. Generally, acceptable curl values for recording sheets employed in electrophotographic processes are from 0 to about 15 millimeters and acceptable curl values for recording sheets employed in ink jet printing processes are from 0 to about 20 millimeters. Image recording on more highly curled substrates can be imprecise, and higher degrees of curl can result in jamming when the sheet is fed through the machine. In addition, in ink jet printing processes, since the printhead is always moving, it can be entangled with curled sheets, thereby jamming the machine. In contrast to recording sheets of the present inYention, transparencies coated on one side with an ink receiving layer and with no heat absorbing layer will curl into tubes when subjected to varying humidity conditions and heat. Transparency materials coated on both sides with ink receiving layers and subjected to varying humidity conditions and heat typically will exhibit curl values of from about 100 to about 150 millimeters. Transparency materials having a moisture resistant coating, when subjected to varying humidity condiLions and heat will typically exhibit curl values of from about 50 to about 100 ", " "~
The recording sheets of the present invention also exhibit little or no blocking. Blocking refers to the transfer of ink or toner from a printed image from one sheet to another when recording sheets are stacked together. The recording sheets of the present invention exhibit substantially no blocking under, for example, environmental conditions of from about 20 to about 80 percent relative humidity and at temperatures of about 65CC.
Further, the recording sheets of the present invention exhibit high resistance to humidity. Resistance to humidity generally is the capacity of a recording sheet to control the blooming and bleeding of printed images, wherein blooming r~:p~s~"l~ intra-diffusion of dyes and bleeding represents inter-diffusion of dyes. The blooming test can be performed by printing a bold filled letter such as T on a recording sheet and placing the sheet in a constant environment chamber preset for humidity and temperature. The vertical and horizontal spread of the dye in the letter T is 2~ 72 monitored periodically under a microscope. Resistance to humidity limit is established when the dyes selected begin to diffuse out of the letterT. The bleeding test is performed by printing a checker board square pattern of various different colors and measuring the inter-diffusion of colors as a function of humidity and temperature.
Specific embodiments of the invention will now be described in detail. These examples are intended to be illustrative, and the invention is not limited to the materials, conditions, or process parameters set forth in these embodiments. All parts and percentages are by weight unless otherwise indicated.
The optical density measurements recited herein were obtained on a Pacific 5pectrograph Color System. The system consists of two major components, an optical sensor and a data terminal. The optical sensor employs a 6 inch integrating sphere to provide diffuse illumination and 8 degrees viewing. This sensor can be used to measure both transmission and reflectance samples. When reflectance samples are measured, a specular component may be included. A high resolution, full dispersion, grating monochromator was used to scan the spectrum from 380 to 720 nanometers. The data terminal features a 12 inch CRT display, numerical keyboard for selection of operating parameters and the entry of tristimulus values, and an alphanumeric keyboard for entry of product standard information.
EXAMPLE I
Twenty transparent recording sheets were prepared by the solvent extrusion process (single side each time initially) on a Faustel Coater by providing for each a MylarT~ base sheet (roll form~ with a thickness of 75 microns and coating the base sheet with a copolymer of vinylidene fluoride/hexafluoropropylene (Viton E-45, obtained from E.l. Du Pont de Nemours & Company), which copolymerwas present in a concentration of 5 percent by weight i~ acetone. Subsequent to air drying at 60'C and monitoring the .lirre~ei~ce in weight prior to and subsequent to coating, the dried MylarD' rolls were coated on one side with 0.5 gram, 5 microns in 2~ 7~
thickness, of a vinylidene fluoride/hexafluoro propylene copolymer heat absorbing layer. The dried heat absorbing layer was then overcoated on the Faustel Coater in each instance with a second anticurl hydrophilic layer of hydroxypropylmethyl cellulose (Methocel K35LV, obtained from Dow Chemical Company), present in a concentration of 4 percent by weight in a mixture of water (75 percent by weight) and methanol (25 percent by weight). Subsequent to air drying at a temperature of 100C and monitoring the difference in weight prior to and subsequent to coating, the sheets were coated with 0.7 gram, in a thickness of 7 microns, of the hydrophilic polymer anticurl layer in contact with the vinylidene fluoride/hexafluoro propylene heat absorbing layer. Rewinding the coated side of the Mylar'~ onto an empty core and using these rolls, the uncoated sides of the Mylar'`' were coated in each instance (20 sheets) with a hydrophilic ink receiving layer comprising a blend of 25 percent by weight sodium carboxymethyl cellulose (CMC 7HOF, obtained from Hercules Chemical Company), 25 percent by weight of poly(ethylene oxide) (POLYOX
WSRN-30û0, obtained from Union Carbide Company), and 50 percent by weight of hydroxypropylmethyl cellulose (Methocel D35LV, obtained from Dc~w Chemical Company), which blend was present in a concentration of 4 percent by weight in water. Subsequent to air drying at 100C and monitoring the weight prior to and subsequent to coating, the sheets were coated with 0.8 gram, in a thickness of 8 microns, of the ink receiving layer.
Half of these sheets (10) were then fed individually into a Xerox~ 4020'`' ink jet color printer containing four separate inks (commercially available and obtained from Sharp Inc. as inks for the 4020'~) which comprised water, glycols, and magenta, cyan, yellow or black dyes, respectively. Images were obtained on the ink receiving layers with average optical densities for the 10 sheets of 1.15 (black), 1.34 tmagenta), 0.84 (cyan) and 0.57 (yellow).
These imaged transparency sheets were then stacked one over the other (the imaged side of one sheet in contact with the nonimaged side of the adjacent sheet) and placed iri an environment chamber preset at 80F and 80 percent relative humidity (RH) for a period of 24 hours. Under these conditions, no transfer of colors occurred from the imaged side of one 2~ 72 sheet to the nonimaged side of the adjacent sheet, and the optical density of the images remained unchanged. The imaged sheets did not stick together and exhibited a curl value of zero. Upon lowering the humidity of the environment chamber from 80 percent to 20 percent, the imaged sheets evidenced an acceptable curl value of between zero and 10 millimeters and no transfer of ink occurred from one sheet to the adjacent sheet. The other 10 sheets were fed into an experimental heat assisted ink jet printer test fixture equipped with a platen heater. Each of the sheets was imaged as it lay on the stationary platen heater set at 65C, using movable ink jet heads carrying an aqueous black ink, for a period of from about 30 to about 60 seconds. Under these conditions the record ing sheets of the present invention yielded acceptable curl values of between zero and 10 millimeters, and the average optical density of the images was 2.5 Twenty transparent recording sheets were prepared by the solvent extrusion process (single side each time initially) on a Faustel Coater by providing a Mylar~" base sheet (roll form) in a thickness of 100 microns and coating the base sheet with a copolymer, dimethylsiloxane-b-bisphenol A carbonate (Scientific Polymer Products #78g), which solution was present in a concentration of 5 percent by weight in dichloromethane. Subsequent to air drying at 100C and monitoring the difference in weight prior to and subsequent to coating, the dried Mylarl~ roll was coated on one side with 0 9 gram, 9 microns in thickness, of a dimethylsiloxane-b-bisphenol A
carbonate copolymer heat absorbing layer. The dried copolymer layer was then overcoated on the Faustel Coater with a hydrophilic layer of sodium carboxymethyl cellulose (CMC 7HOF, obtained from Hercules Chemical Company), which cellulose was present in a concentration of 2 percent by weight in a mixture of methanol (25 percent by weight) and water (75 percent by weight). Subsequent to air drying at a t~i"perdlure of 100C
and monitoring the difference in weight prior to and subsequent to coating, each of the 20 sheets were coated with 0.6 gram, 6 microns in thickness, of the hydrophilic polymer anticurl layer in contact with the ~ 33 7~
dimethyl siloxane-b-bisphenol A carbonate copolymer heat absorbing layer. Rewinding the coated side of the MylarrU coated with the two layers on an empty core and using this roll, the uncoated side of the Mylarr~ was coated with a hydrophilic ink receiving layer comprising a blend of 80 percent by weight of hydroxypropylmethyl cellulose (Methocel K35LV, obtained from Dow Chemical Company) and 20 percent by weight of poly(ethylene oxide) ~POLYOX WSRN-30ûû, obtained from Union Carbide Company), which blend was present in a concentration of 4 percent by weight in water. Subsequent to air drying at 100C and monitoring the weight prior to and subsequent to coating, each of the sheets was coated with 0.8 gram, in a thickness of 8 microns, of the ink receiving layer. Ten of the transparency sheets were then fed individually into a Xerox~ 4020TU ink jet color printer as in Example I, and images were obtained with average optical densities of 1.10 (black), 1.25 (magenta), 0.80 (cyan) and 0.57 (yellow). These imaged sheets were stacked one over the other and placed in an environment chamber preset at 80F and 80 percent RH for a period of 24 hours. Under these conditions, no transfer of colors occurred from the imaged side of one sheet to the nonimaged side of the adjacent sheet, and the optical density of the images remained unchanged. The imaged sheets did not stick together and yielded a curl value of zero. Upon lowering the humidity (RH) of the environment chamber from 80 percent to 20 percent, the imaged sheets yielded curl values of between zero and 10 millimeters, and no ink transfer occurred from one transparency sheet to the adjacent tranparencysheet. Theother10sheetswerefedintoanexperimentalheat assisted ink jet printer equipped with a platen heater. Each of the sheets was imaged as it lay on the stationary platen heater set at 65C, using movable ink jet heads carrying an aqueous black ink, for a period of from about30toabout60se~onds. Undertheseconditionsthetransparenciesof the present invention yielded acceptable curl values of between zero and 10 millimeters, and the average optical density of the images was 2.5.

2~a~72 Ten transparent recording sheets were prepared by the solvent extrusion process (single side each time) on a Faustel Coater by providing a Mylarn' base sheet (roll form) in a thickness of 100 microns and coating the base sheet with a copolymer of styrene/butadiene (butadiene content of 70 percent by weight, obtained from Shell Company), which solution was present in a concentration of 2 percent by weight of toluene. Subsequent to air drying at 1 00C and monitoring the difference in weight prior to and subsequent to coating, the dried Mylar"' roll was coated on one side with 0.3 gram, 3 microns in thickness, of the styrene/butadiene copolymer heat absorbing layer. The dried copolymer layer was then overcoated on the Faustel Coater with an anticurl layer of a hydrophilic sodium carboxymethyl cellulose (CMC 7HOF, obtained from Hercules Chemical Company), which cellulose was present in a concentration of 1 percent by weight in a mixture of methanol (25 percent by weight) and water (75 percent by weight).
Subsequent to air drying at a temperature of 100C and monitoring the difference in weight priorto and subsequentto coating, the 10 transparent sheets were coated with 0.3 gram, 3 microns in thickness, of the hydrophilic polymer anticurl layer in contact with the styrene/butadiene copolymer heat absorbing layer Rewinding the coated side of the MylarTU on an empty core, and using this roll with the two layers, the uncoated side of the Mylar~ was coated with a hydrophobic ink receiving layer comprising a blend of 80 percent by weight of poly(a-methylstyrene) (Amoco resin 18-29, obtained from Amoco Chemical Company) and 20 percent by weight of poly(chloroprene), which blend was present in a concentration of 2 percent by weight in toluene. Subsequent to air drying at 100~C and monitoring the weight prior to and subsequent to coating, the sheets were coated with 0.3 gram, in a thickness of 3 microns, of the ink receiving layer. The resulting 10 l,d,~,,.,ar~n~y sheets were then fed individually into a Xerox0 1005T~ color xerographic imaging apparatus. The average optical density of the images obtained was 1.6 (black), 0.80 (yellow), 1.40 (magenta) and 1.50 (cyan). These images could not be handwiped or lifted off with 3M
scotch tape 6û seconds subsequent to their preparation. The curl value of . -35-2~6572 these sheets before and after printing was in the acceptable range of zero to 10 millimeters.
Other embodiments and modifications of the present invention may occur to those skilled in the art subsequent to a review of the information presented herein; these embodiments and modifications, as well as equivalents thereof, are also included within the scope of this invention.

Claims (32)

1. A recording sheet which comprises, in the order stated, an ink receiving layer, a base sheet, a heat absorbing layer, and an anticurl layer.

2. A recording sheet according to claim 1 wherein the sheet is substantially transparent

3. A recording sheet according to claim 2 wherein the base sheet is of a material selected from the group consisting of polyesters, polycarbonates, polysulfones, cellulose triacetate, polyvinyl chloride, cellophane, polyvinyl fluoride, and mixtures thereof.

4. A recording sheet according to claim 1 wherein the sheet is opaque.

5. A recording sheet according to claim 4 wherein the base sheet is of a material selected from the group consisting of paper, opaque plastics, and filled polymers.

6. A recording sheet according to claim 1 wherein the base sheet has a thickness of from about 50 to about 125 microns.

7. A recording sheet accolding to claim 1 wherein the ink receiving layer is hydrophilic.

8. A recording sheet according to claim 1 wherein the ink receiving layer is of a material selected from the group consisting of:
a. binary blends comprising poly(ethylene oxide) and a component selected from the group consisting of (i) hydroxypropyl methyl cellulose; (ii) vinylmethyl ether/maleic acid copolymers; (iii) acrylamidelacrylic acid copolymers; (iv) carboxymethylhydroxyethyl cellulose salts;
(v) hydroxyethyl cellulose; (vi) water soluble ethylhydroxyethyl cellulose; (vii) cellulose sulfate; (viii) poly(vinyl alcohol); (ix) poly(vinyl pyrrolidone); (x) hydroxybutylmethyl cellulose; (xi) hydroxypropyl cellulose;
(xii) poly(2-acrylamido-2-methyl propane sulfonic acid);
(xiii) methyl cellulose; (xiv) hydroxyethylmethyl cellulose;
(xv) cellulose acetate; (xvi) cellulose acetate hydrogen phthalate; (xvii) hydroxypropylmethyl cellulose phthalate;
(xviii) vinylalcohol/vinylacetate copolymers; (xix) vinylalcohollvinylbutyral copolymers; (xx) saits of carboxymethyl cellulose; and (xxi) vinyl pyrrolidone/vinyl acetate copolymers;
b. ternary blends comprising poly(ethylene oxide), salts of carboxymethyl cellulose, and a component selected from the group consisting of (i) hydroxypropyl methyl cellulose;
(ii) vinylmethyl etherlmaleic acid copolymers; (iii) acrylamidelacrylic acid copolymers; (iv) salts of carboxymethylhydroxyethyl cellulose; (v) hydroxyethyl cellulose; (vi) water soluble ethylhydroxyethyl cellulose;
(vii) cellulose sulfate; (viii) poly(vinyl alcohol); (ix) poly(vinyl pyrrolidone); (x) hydroxybutylmethyl cellulose;
(xi) hydroxypropyl cellulose; (xii) poly(2-acrylamido-2-methyl propane sulfonic acid); (xiii) methyl cellulose; (xiv) hydroxyethylmethyl cellulose; (xv) poly(diethylene triamine-co-adipic acid); (xvi) poly(imidazoline) quaternized; (xvii) poly(ethylene imine) epichlorohydrin modified; (xviii) poly(N,N dimethyl-3, 5-dimethylene piperidinium chloride); and (xix) poly(ethylene imine) ethoxylated; and c. ternary blends of poly(ethylene oxide), hydroxyalkylmethyl cellulose, and a component selected from the group consisting of (i) hydroxypropyl cellulose; (ii) vinylmethyl ether/maleic acid copolymers; (iii) acrylamide/acrylic acid copolymers; (iv) salts of carboxymethylhydroxyethyl cellulose; (v) hydroxyethyl cellulose; (vi) water soluble ethylhydroxyethyl cellulose; (vii) cellulose sulfate; (viii) poly(vinyl alcohol); (ix) poly(vinyl pyrrolidone); (x) poly(2-acrylamido-2-methyl propane sulfonic acid); (xi) methyl cellulose; (xii) salts of carboxymethyl cellulose; (xiii) poly(diethylene triamine-co-adipic acid); (xiv) poly(imidazoline) quaternized; (xv) poly(ethylene imine) epichlorohydrin modified; (xvi) poly(N,N-dimethyl-3,5-dimethylene piperidinium chloride); and (xvii) poly(ethyleneimine) ethoxylated.

9. A recording sheet according to claim 1 wherein the ink receiving layer is hydrophobic.

10. A recording sheet according to claim 1 wherein the ink receiving layer is of a material comprising a binary blend of poly(.alpha.-methyl styrene) and a component selected from the group consisting of (i) poly(ethylene oxide); (ii) halogenated rubber; (iii) halogenated poly(propylene); (iv) halogenated poly(ethylene); (v) poly(caprolactone);
(vi) poly(chloroprene); (vii) poly(1,4-butylene adipate); (viii) poly(vinylmethylether); (ix) poly(vinylisobutylether); (x) styrene-butadiene copolymers; and (xi) ethyl cellulose.

11. A recording sheet according to claim 1 wherein the ink receiving layer has a thickness of from about 1 to about 25 microns.

12. A recording sheet according to claim 1 wherein the ink receiving layer contains a filler material in an amount of from about 1 to about 25 percent by weight of the ink receiving layer, said filler being selected from the group consisting of inorganic oxides, colloidal silicas, calcium carbonate, and mixtures thereof.

13. A recording sheet according to claim 1 wherein the heat absorbing layer is of a material selected from the group consisting of (i) vinylidene fluoride/hexafluoropropylene copolymers; (ii) vinylidene fluoride/hexafluoro propylene/tetrafluoroethylene copolymers; (iii) vinylidene fluoride/tetrafluoroethylene/perfluoro methylvinyl ether terpolymers; (iv) tetrafluoro propylene/propylene copolymers; (v) vinylidene fluoride/chloro trifluoroethylene copolymers; (vi) tetrafluoroethylene/ethylene copolymers; (vii) tetrafluoroethylene/hexafluoropropylene copolymers; (viii) poly(vinyl fluoride); (ix) poly(vinylidene fluoride); (x) styrene-b-isoprene-b-dimethylsiloxane triblock copolymers; (xi) dimethyl siloxane-b-bisphenol A
carbonate diblock copolymers; (xii) dimethylsiloxane-b-.alpha.-methyl styrene diblock copolymers; (xiii) poly(sulfone); (xiv) poly(sulfide); (xv) chlorosulfonated poly(ethylene); (xvi) acrylonitrile/butadiene copolymers;
(xvii) acrylonitrile/butadiene/styrene terpolymers; (xviii) styrene/butadiene copolymers; (xix) styrene/isoprene diblock copolymers; (xx) isobutylene/isoprene halogenated copolymers; (xxi) ethylene/propylene rubber; (xxii) ethylene/ethylacrylate copolymers; (xxiii) ethylene/propylene/diene terpolymers; (xxiv) ethylene/vinyl acetate copolymers; (xxv) ethylene/maleic anhydride copolymers; and mixtures thereof.

14. A recording sheet according to claim 1 wherein the heat absorbing layer has a thickness of from about 1 to about 25 microns.

15. A recording sheet according to claim 1 wherein an additional heat absorbing layer is situated between the ink receiving layer and the base sheet.

16. A recording sheet according to claim 15 wherein the heat absorbing layer situated between the base sheet and the anticurl layer has a thickness of from about 1 to about 25 microns and the additional heat absorbing layer situated between the base sheet and the ink receiving layer has a thickness of from about 1 to about 10 microns.

17. A recording sheet according to claim 1 wherein the anticurl layer is of a material selected from the group consisting of (i) hydroxypropylmethyl cellulose; (ii) hydroxybutylmethyl cellulose; (iii) hydroxyethylmethyl cellulose; (iv) hydroxyethyl cellulose; (v) ethylhydroxyethyl cellulose; (vi) salts of carboxymethyl cellulose; (vii) salts of carboxymethyl hydroxyethyl cellulose; (viii) methyl cellulose; (ix) poly(acrylamide) polymers; (x) cellulose sulfate; (xi) hydroxyalkylmethyl cellulose; (xii) acrylamide-acrylic acid copolymers; and mixtures thereof.

18. A recording sheet according to claim 1 wherein the anticurl layer has a thickness of from about 1 to about 25 microns.

19. A process which comprises applying a recording liquid in an imagewise pattern to a recording sheet which comprises, in the order stated, an ink receiving layer, a base sheet, a heat absorbing layer, and an anticurl layer.

20. A process according to claim 19 wherein the recording sheet has an additional heat absorbing layer situated between the ink receiving layer and the base sheet.

21. A printing process which comprises (1) incorporating into an ink jet printing apparatus containing an ink a recording sheet which comprises, in the order stated, an ink receiving layer, a base sheet, a heat absorbing layer, and an anticurl layer, and causing droplets of the ink to be ejected in an imagewise pattern onto the recording sheet, thereby generating images on the recording sheet.

22. A process according to claim 21 wherein the recording sheet has an additional heat absorbing layer situated between the ink receiving layer and the base sheet.

23. A printing process according to claim 21 wherein the ink receiving layer is hydrophilic.

24. A printing process according to claim 21 wherein the ink receiving layer is of a material selected from the group consisting of:
a. binary blends comprising poly(ethylene oxide) and a component selected from the group consisting of (i) hydroxypropyl methyl cellulose; (ii) vinylmethyl ether/maleic acid copolymers; (iii) acrylamide/acrylic acid copolymers; (iv) carboxymethylhydroxyethyl cellulose salts;
(v) hydroxyethyl cellulose; (vi) water soluble ethylhydroxyethyl cellulose; (vii) cellulose sulfate; (viii) poly(vinyl alcohol); (ix) poly(vinyl pyrrolidone); (x) hydroxybutylmethyl cellulose; (xi) hydroxypropyl cellulose;
(xii) poly(2-acrylamido-2-methyl propane sulfonic acid);
(xiii) methyl cellulose; (xiv) hydroxyethylmethyl cellulose;
(xv) cellulose acetate; (xvi) cellulose acetate hydrogen phthalate; (xvii) hydroxypropylmethyl cellulose phthalate;
(xviii) vinylalcohol/vinylacetate copolymers; (xix) vinylalcohol/vinylbutyral copolymers; (xx) salts of carboxymethyl cellulose; and (xxi) vinyl pyrrolidone/vinyl acetate copolymers;
b. ternary blends comprising poly(ethylene oxide), salts of carboxymethyl cellulose, and a component selected from the group consisting of (i) hydroxypropyl methyl cellulose;
(ii) vinylmethyl ethel/maleic acid copolymers; (iii) acrylamide/acrylic acid copolymers; (iv) salts of carboxymethylhydroxyethyl cellulose; (v) hydroxyethyl cellulose; (vi) water soluble ethylhydroxyethyl cellulose;
(vii) cellulose sulfate; (viii) poly(vinyl alcohol); (ix) poly(vinyl pyrrolidone); (x) hydroxybutylmethyl cellulose;
(xi) hydroxypropyl cellulose; (xii) poly(2-acrylamido-2-methyl propane sulfonic acid); (xiii) methyl cellulose; (xiv) hydroxyethylmethyl cellulose; (xv) poly(diethylene triamine-co-adipic acid); (xvi) poly(imidazoline) quaternized; (xvii) poly(ethylene imine) epichlorohydrin modified; (xviii) poly(N,N dimethyl-3, 5-dimethylene piperidinium chloride); and (xix) poly(ethylene imine) ethoxylated; and c. ternary blends of poly(ethylene oxide), hydroxyalkylmethyl cellulose, and a component selected from the group consisting of (i) hydroxypropyl cellulose; (ii) vinylmethyl ether/maleic acid copolymers; (iii) acrylamide/acrylic acid copolymers; (iv) salts of carboxymethylhydroxyethyl cellulose; (v) hydroxyethyl cellulose; (vi) water soluble ethylhydroxyethyl cellulose; (vii) cellulose sulfate; (viii) poly(vinyl alcohol); (ix) poly(vinyl pyrrolidone); (x) poly(2-acrylamido-2-methyl propane sulfonic acid); (xi) methyl cellulose; (xii) salts of carboxymethyl cellulose; (xiii) poly(diethyiene triamine-co-adipic acid); (xiv) poly(imidazoline) quaternized; (xv) poly(ethylene imine) epichlorohydrin modified; (xvi) poly(N,N-dimethyl-3,5-dimethylene piperidinium chloride); and (xvii) poly(ethyleneimine) ethoxylated.

25. A process for generating images which comprises generating an elctrostatic latent image on an imaging member in an imaging apparatus, developing the latent image with a toner, transferring the developed image to a recording sheet which comprises, in the order stated, an ink receiving layer, a base sheet, a heat absorbing layer, and an anticurl layer, and optionally permanently affixing the trarlsferred image to the recording sheet.

26. A process according to claim 25 wherein the recording sheet has an additional heat absorbing layer situated between the ink receiving layer and the base sheet

27. A process according to claim 25 wherein the ink receiving layer is hydrophobic.

28. A process according to claim 25 wherein the ink receiving layer is of a material comprising a binary blend of poly(.alpha.-methyl styrene)and a component selected from the group consisting of (i) poly(ethylene oxide); (ii) halogenated rubber; (iii) halogenated poly(propylene); (iv) halogenated poly(ethylene); (v) poly(caprolactone); (vi) poly(chloroprene);
(vii) poly(1,4-butylene adipate); (viii) poly(vinylmethylether); (ix) poly(vinylisobutylether); (x) styrene-butadiene copolymers; and (xi) ethyl cellulose.

29. An imaging process which comprises generating an electrostatic latent image on a recording sheet which comprises, in the order stated, an ink receiving layer, a base sheet, a heat absorbing layer, and an anticurl layer, developing the latent image with a toner, and optionally permanently affixing the developed image to the recording sheet.

30. A process according to claim 29 wherein the recording sheet has an additional heat absorbing layer situated between the ink receiving layer and the base sheet.

31. A process according to claim 29 wherein the ink receiving layer is hydrophobic.

32. A process according to ciaim 29 wherein the ink receiving layer is of a material comprising a binary blend of poly(.alpha.-methyl styrene)and a component selected from the group consisting of (i) poly(ethylene oxide); (ii) halogenated rubber; (iii) halogenated poly(propylene); (iv) halogenated poly(ethylene); (v) poly(caprolactone); (vi) poly(chloroprene);
(vii) poly(1,4-butylene adipate); (viii) poly(vinylmethylether); (ix) poly(vinylisobutylether); (x) styrene-butadiene copolymers; and (xi) ethyl cellulose.