Mixture of dyes for black dye donor for thermal color proofing

A black dye-donor element for thermal dye transfer comprising a support having thereon a dye layer comprising a mixture of at least one cyan, magenta and yellow dyes dispersed in a polymeric binder, at least one of the cyan dyes having the formula: ##STR1## and at least one of the yellow dyes having the formula: ##STR2## and at least one of the magenta dyes having the formula: ##STR3##

This invention relates to use of a mixture of cyan, yellow and magenta dyes 
in a black dye-donor element for thermal dye transfer imaging which can be 
used in a four-color proofing system that accurately represents the hue of 
a printed color image obtained from a printing press. 
In order to approximate the appearance of continuous-tone (photographic) 
images via ink-on-paper printing, the commercial printing industry relies 
on a process known as halftone printing. In halftone printing, color 
density gradations are produced by printing patterns of dots or areas of 
varying sizes, but of the same color density, instead of varying the color 
density continuously as is done in photographic printing. 
There is an important commercial need to obtain a color proof image before 
a printing press run is made. It is desired that the color proof will 
accurately represent at least the details and color tone scale of the 
prints obtained on the printing press. In many cases, it is also desirable 
that the color proof accurately represent the image quality and halftone 
pattern of the prints obtained on the printing press. In the sequence of 
operations necessary to produce an ink-printed, full-color picture, a 
proof is also required to check the accuracy of the color separation data 
from which the final three or more printing plates or cylinders are made. 
Traditionally, such color separation proofs have involved silver halide 
photographic, high-contrast lithographic systems or non-silver halide 
light-sensitive systems which require many exposure and processing steps 
before a final, full-color picture is assembled. Colorants that are used 
in the printing industry are insoluble pigments. In particular, carbon is 
often used in such a black ink and results in fairly uniform absorbance 
across the visible spectrum. In thermal transfer color printing systems 
that use diffusible dyes it is often difficult to find a blend of two or 
more dyes which yields both uniform neutral (black) color and fulfills the 
other requirements of the printing system such as transfer efficiency and 
donor storage stability. In U.S. patent application Ser. No. 514,643, 
filed Apr. 25, 1990, of DeBoer, a process is described for producing a 
direct digital, halftone color proof of an original image on a 
dye-receiving element. The proof can then be used to represent a printed 
color image obtained from a printing press. The process described therein 
comprises: 
a) generating a set of electrical signals which is representative of the 
shape and color scale of an original image; 
b) contacting a dye-donor element comprising a support having thereon a dye 
layer and an infrared-absorbing material with a first dye-receiving 
element comprising a support having thereon a polymeric, dye 
image-receiving layer; 
c) using the signals to imagewise-heat by means of a diode laser the 
dye-donor element, thereby transferring a dye image to the first 
dye-receiving element; and 
d) retransferring the dye image to a second dye image-receiving element 
which has the same substrate as the printed color image. 
In the above process, multiple dye-donors are used to obtain a complete 
range of colors in the proof. For example, for a full-color proof, four 
colors: cyan, magenta, yellow and black are normally used. 
By using the above process, the image dye is transferred by heating the 
dye-donor containing the infrared-absorbing material with the diode laser 
to volatilize the dye, the diode laser beam being modulated by the set of 
signals which is representative of the shape and color of the original 
image, so that the dye is heated to cause volatilization only in those 
areas in which its presence is required on the dye-receiving layer to 
reconstruct the original image. 
Similarly, a thermal transfer proof can be generated by using a thermal 
head in place of a diode laser as described in U.S. Pat. No. 4,923,846. 
Commonly available thermal heads are not capable of generating halftone 
images of adequate resolution but can produce high quality continuous tone 
proof images which are satisfactory in many instances. U.S. Pat. No. 
4,923,846 also discloses the choice of mixtures of dyes for use in thermal 
imaging proofing systems. The dyes are selected on the basis of values for 
hue error and turbidity. The Graphic Arts Technical Foundation Research 
Report No. 38, "Color Material" (58-(5) 293-301, 1985 gives an account of 
this method. 
An alternative and more precise method for color measurement and analysis 
uses the concept of uniform color space known as CIELAB in which a sample 
is analyzed mathematically in terms of its spectrophotometric curve, the 
nature of the illuminant under which it is viewed and the color vision of 
a standard observer. For a discussion of CIELAB and color measurement, see 
"Principles of Color Technology", 2nd Edition, p. 25-110, 
Wiley-Interscience and "Optical Radiation Measurements", Volume 2, p. 
33-145, Academic Press. 
In using CIELAB, colors can be expressed in terms of three parameters: L*, 
a* and b*, where L* is a lightness function, and a* and b* define a point 
in color space. Thus, a plot of a* v. b* values for a color sample can be 
used to accurately show where that sample lies in color space, i.e., what 
its hue is. This allows different samples to be compared for hue if they 
have similar density and L* values. 
In color proofing in the printing industry, it is important to be able to 
match the proofing ink references provided by the International Prepress 
Proofing Association. These ink references are density patches made with 
standard 4-color process inks and are known as SWOP (Specifications Web 
Offset Publications) Color References. For additional information on color 
measurement of inks for web offset proofing, see "Advances in Printing 
Science and Technology", Proceedings of the 19th International Conference 
of Printing Research Institutes, Eisenstadt, Austria, June 1987, J. T. 
Ling and R. Warner, p. 55. 
Thus, this invention relates to the use of a mixture of cyan, yellow and 
magenta dyes for thermal dye transfer imaging to approximate a hue match 
of the black SWOP Color Reference. The mixtures of dyes described in this 
invention provide a closer hue match to the SWOP standard and better 
transfer density than the preferred dye mixtures of U.S. Pat. No. 
4,923,846. 
In U.S. Pat. No. 4,816,435, a combination of thermally transferable dyes is 
disclosed for use in producing black images. The dye types disclosed are 
di- and tri-cyanovinylanilines (for the yellow and magenta respectively) 
and phenol-based indoaniline cyan dyes. There is a problem with using 
these dyes in dye-donors in that the storage stability is not as good as 
one would like it to be. It would be desirable to provide a black 
dye-donor with good storage stability. 
Accordingly, this invention relates to a black dye-donor element for 
thermal dye transfer comprising a support having thereon a dye layer 
comprising a mixture of cyan, yellow and magenta dyes dispersed in a 
polymeric binder, at least one of the cyan dyes having the formula: 
##STR4## 
wherein R.sup.1 and R.sup.2 each independently represents hydrogen; an 
alkyl group having from 1 to about 10 carbon atoms; a cycloalkyl group 
having from about 5 to about 7 carbon atoms; allyl; or such alkyl, 
cycloalkyl or allyl groups substituted with one or more groups such as 
alkyl, aryl, alkoxy, aryloxy, amino, halogen, nitro, cyano, thiocyano, 
hydroxy, acyloxy, acyl, alkoxycarbonyl, aminocarbonyl, alkoxycarbonyloxy, 
carbamoyloxy, acylamido, ureido, imido, alkylsulfonyl, arylsulfonyl, 
alkylsulfonamido, arylsulfonamido, alkylthio, arylthio, trifluoroethyl, 
etc., e.g., methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, 
methoxyethyl, benzyl, 2-methanesulfonamidoethyl, 
2-hydroxyethyl,2-cyanoethyl, methoxycarbonylmethyl, cyclohexyl, 
cyclopentyl, phenyl, pyridyl, naphthyl, thienyl, pyrazolyl, p-tolyl, 
p-chlorophenyl, m-(N-methyl-sulfamoyl)phenylmethyl, methylthio, butylthio, 
benzylthio, methanesulfonyl, pentanesulfonyl, methoxy, ethoxy, 
2-methane-sulfonamidoethyl, 2-hydroxyethyl, 2-cyanoethyl, 
methoxy-carbonyl-methyl, imidazolyl, naphthyloxy, furyl, p-tolylsulfonyl, 
p-chlorophenylthio, m-(N-methyl sulfamoyl)phenoxy, ethoxy-carbonyl, 
methoxyethoxycarbonl, phenoxy-carbonyl, acetyl, benzoyl, 
N,N-dimethyl-carbamoyl, dimethylamino, morpholino, anilino, pyrrolidino 
etc.; with the proviso that R.sup.1 and R.sup.2 cannot both be hydrogen; 
or R.sup.1 and R.sup.2 can be joined together to form, along with the 
nitrogen to which they are attached, a 5- to 7-membered heterocyclic ring 
such as morpholine or pyrrolidine; 
or either or both of R.sup.1 and R.sup.2 can be combined with an R.sup.3 to 
form a 5- to 7-membered heterocyclic ring; 
each R.sup.3 independently represents substituted or unsubstituted alkyl, 
cycloalkyl or allyl as described above for R.sup.1 and R.sup.2 ; alkoxy, 
aryloxy, halogen, thiocyano, acylamido, ureido, alkylsulfonamido, 
arylsulfonamido, alkylthio, arylthio or trifluoromethyl; 
or any two of R.sup.3 may be combined together to form a 5- or 6-membered 
carbocyclic or heterocyclic ring; or one or two of R.sup.3 may be combined 
with either or both of R.sup.1 and R.sup.2 to complete a 5- to 7-membered 
ring; 
m is an integer of from 0 to 4; 
R.sup.4 represents hydrogen or an electron withdrawing group such as cyano, 
alkoxycarbonyl, aminocarbonyl, alkylsulfonyl, arylsulfonyl, acyl, nitro, 
etc.; 
R.sup.5 represents an electron withdrawing group such as those listed above 
for R.sup.4 ; an aryl group having from about 6 to about 10 carbon atoms; 
a hetaryl group having from about 5 to about 10 atoms; or such aryl or 
hetaryl groups substituted with one or more groups such as are listed 
above for R.sup.1 and R.sup.2 ; 
R.sup.6 and R.sup.7 each independently represents an electron withdrawing 
group such as those described above for R.sup.4 ; or R.sup.6 and R.sup.7 
may be combined to form the residue of an active methylene compound such 
as a pyrazolin-5-one, a pyrazoline-3,5-dione, a thiohydantoin, a 
barbituric acid, a rhodanine, a furanone, an indandione, etc., 
and at least one of the yellow dyes having the formula: 
##STR5## 
wherein: R.sup.8, R.sup.9 and R.sup.11 each independently represents a 
substituted or unsubstituted alkyl group of from 1 to about 10 carbon 
atoms, such as those listed above for R.sup.1 ; a cycloalkyl group of from 
about 5 to about 7 carbon atoms, such as those listed above for R.sup.1 ; 
an allyl group, such as those listed above for R.sup.1 ; or an aryl group 
having from about 6 to about 10 carbon atoms, such as phenyl, naphthyl, 
p-tolyl, m-chlorophenyl, p-methoxyphenyl, m-bromophenyl, o-tolyl, etc.; 
or R.sup.8 and R.sup.9 can be joined together to form, along with the 
nitrogen to which they are attached, a 5- or 6-membered heterocyclic ring, 
such as a pyrrolidine or morpholine ring; 
or either or both of R.sup.8 and R.sup.9 can be joined to the carbon atom 
of the benzene ring at a position ortho to the position of attachment of 
the anilino nitrogen to form a 5- or 6-membered ring, thus forming a 
polycyclic system such as 1,2,3,4-tetrahydroquinoline, julolidine, 
2,3-dihydroindole, or benzomorpholine; 
R.sup.10 represents hydrogen; a substituted or unsubstituted alkyl group of 
from 1 to about 10 carbon atoms, such as those listed above for R.sup.1 ; 
a cycloalkyl group of from about 5 to about 7 carbon atoms, such as those 
listed above for R.sup.1 ; an allyl group, such as those listed above for 
R.sup.1 ; halogen; carbamoyl, such as N,N-dimethylcarbamoyl; or 
alkoxycarbonyl, such as ethoxycarbonyl or methoxyethoxy-carbonyl; 
R.sup.12 represents a substituted or unsubstituted alkoxy group having from 
1 to about 10 carbon atoms, such as methoxy, ethoxy, methoxyethoxy or 
2-cyanoethoxy; a substituted or unsubstituted aryloxy group having from 
about 6 to about 10 carbon atoms, such as phenoxy, m-chlorophenoxy, or 
naphthoxy; NHR.sup.13 ; NR.sup.13 R.sup.14 or the atoms, such as O, 
CH.sub.2, S, NR.sup.13, etc., necessary to complete a 6-membered ring 
fused to the benzene ring; 
R.sup.13 and R.sup.14 each independently represents any of the groups for 
R.sup.8, or R.sup.13 and R.sup.14 may be joined together to form, along 
with the nitrogen to which they are attached, a 5- or 6-membered 
heterocyclic ring, such as a pyrrolidine or morpholine ring; 
n is a positive integer from 1 to 5; and 
G represents a substituted or unsubstituted alkyl or alkoxy group of from 1 
to about 10 carbon atoms, such as those listed above for R.sup.1 and 
R.sup.12 ; halogen; aryloxy; or represents the atoms necessary to complete 
a 5- or 6-membered ring, thus forming a fused ring system such as 
naphthalene, quinoline, isoquinoline or benzothiazole; 
and at least one of the magenta dyes having the formula: 
##STR6## 
wherein R.sup.15 is a substituted or unsubstituted alkyl or allyl group of 
from 1 to about 10 carbon atoms, such as those listed above for R.sup.1 ; 
X is an alkoxy group of from 1 to about 4 carbon atoms or represents the 
atoms which when taken together with R.sup.16 forms a 5- or 6-membered 
ring; 
R.sup.16 is any of the groups for R.sup.15 or represents the atoms which 
when taken together with X forms a 5- or 6-membered ring; 
Y is R.sup.15, an alkoxy group of from 1 to about 4 carbon atoms, hydrogen, 
halogen, or NHJR.sup.17 ; 
R.sup.17 is a substituted or unsubstituted alkyl group of from 1 to about 
10 carbon atoms such as those listed above for R.sup.1, or a substituted 
or unsubstituted aryl group of from about 6 to about 10 carbon atoms such 
as phenyl, naphthyl, p-tolyl, m-chlorophenyl, p-methoxyphenyl, 
m-bromophenyl, o-tolyl, etc.; J is CO, CO.sub.2, --SO.sub.2 -- or 
CONR.sup.20 --; 
R.sup.18 is a substituted or unsubstituted alkyl or allyl group of from 1 
to about 10 carbon atoms, such as those listed above for R.sup.1, or a 
substituted or unsubstituted aryl group of from about 6 to about 10 carbon 
atoms, such as those listed above for R.sup.17 ; 
R.sup.19 is hydrogen, cyano, a substituted or unsubstituted alkyl group of 
from 1 to about 10 carbon atoms, such as those listed above for R.sup.1, 
or a substituted or unsubstituted aryl group of from about 6 to about 10 
carbon atoms, such as those listed above for R.sup.17 ; and 
R.sup.20 is hydrogen or R.sup.18. 
In a preferred embodiment for compounds according to formula I employed in 
the invention, R.sup.4, R.sup.6 and R.sup.7 are cyano. In another 
preferred embodiment for compounds according to formula I employed in the 
invention, R.sup.1 is C.sub.2 H.sub.5, C.sub.2 H.sub.4 OH, or n-C.sub.3 
H.sub.7. In yet another preferred embodiment for compounds according to 
formula I employed in the invention, R.sup.2 is C.sub.2 H.sub.5 or 
n-C.sub.3 H.sub.7. In yet still another preferred embodiment for compounds 
according to formula I employed in the invention, R.sup.3 is hydrogen, 
OC.sub.2 H.sub.5, CH.sub.3 or NHCOCH.sub.3. In another preferred 
embodiment for compounds according to formula I employed in the invention, 
R.sup.5 is p-C.sub.6 H.sub.4 Cl, m-C.sub.6 H.sub.4 NO.sub.2 or naphthyl. 
Compounds included within the scope of formula I employed in the invention 
include the following: 
__________________________________________________________________________ 
##STR7## 
__________________________________________________________________________ 
Compound 
R.sup.1 R.sup.2 
R.sup.3 
R.sup.5 
__________________________________________________________________________ 
1 C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
CH.sub.3 
C.sub.6 H.sub.5 
2 C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
H C.sub.6 H.sub.5 
3 C.sub.2 H.sub.4 OH 
C.sub.2 H.sub.5 
CH.sub.3 
C.sub.6 H.sub.5 
4 C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
OC.sub.2 H.sub.5 
C.sub.6 H.sub.5 
5 n-C.sub.3 H.sub.7 
n-C.sub.3 H.sub.7 
NHCOCH.sub.3 
C.sub.6 H.sub.5 
6 C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
CH.sub.3 
o-C.sub.6 H.sub.4 OCH.sub.3 
7 C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
CH.sub.3 
p-C.sub.6 H.sub.4 OCH.sub.3 
8 C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
CH.sub.3 
p-C.sub.6 H.sub.4 Cl 
9 C.sub.2 H.sub.5 
C.sub. 2 H.sub.5 
CH.sub.3 
m-C.sub.6 H.sub.4 NO.sub.2 
10 C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
CH.sub.3 
##STR8## 
11 C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
CH.sub.3 
##STR9## 
12 C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
CH.sub.3 
##STR10## 
13 C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
H 
##STR11## 
14 C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
CH.sub.3 
p-C.sub.6 H.sub.4 F 
15 C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
CH.sub.3 
o-C.sub.6 H.sub.4 Cl 
16 C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
CH.sub.3 
p-C.sub.6 H.sub.4 CN 
17 C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
CH.sub.3 
3,4-C.sub.6 H.sub.3 Cl.sub.2 
18 C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
CH.sub.3 
2,4-C.sub.6 H.sub.3 Cl.sub.2 
19 C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
CH.sub.3 
##STR12## 
20 C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
CH.sub.3 
##STR13## 
21 C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
CH.sub.3 
##STR14## 
22 C.sub.2 H.sub.4 OH 
C.sub.2 H.sub.5 
CH.sub.3 
p-C.sub.6 H.sub.4 Cl 
23 C.sub.2 H.sub.4 NHSO.sub.2 CH.sub.3 
C.sub.2 H.sub.5 
CH.sub.3 
p-C.sub.6 H.sub.4 Cl 
24 
##STR15## 
25 
##STR16## 
26 
##STR17## 
27 
##STR18## 
__________________________________________________________________________ 
The above dyes may be prepared analogously to the method described in 
Example 1 below. 
In a preferred embodiment for compounds according to formula II employed in 
the invention, R.sup.11 is phenyl; R.sup.12 is ethoxy or NHR.sup.13, 
wherein R.sup.13 is methyl or phenyl; n is 1; and R.sup.10 is hydrogen. 
In another preferred embodiment for compounds according to formula II 
employed in the invention, R.sup.12 is O and completes a 6-membered ring 
fused to the benzene ring. In another preferred embodiment for compounds 
according to formula II employed in the invention, R.sup.12 is NH.sup.13 
R.sup.14, wherein each R.sup.13 and R.sup.14 is methyl or R.sup.13 is 
ethyl and R.sup.14 is phenyl. 
In another preferred embodiment for compounds according to formula II 
employed in the invention, R.sup.12 is NR.sup.13 R.sup.14, wherein 
R.sup.13 and R.sup.14 are joined together to form, along with the nitrogen 
to which they are attached, a pyrrolidine or morpholine ring. 
The compounds of formula II employed in the invention above may be prepared 
by any of the processes disclosed in U.S. Pat. No. 4,866,029, the 
disclosure of which is hereby incorporated by reference. 
Compounds included within the scope of formula II employed in the invention 
include the following: 
__________________________________________________________________________ 
##STR19## 
__________________________________________________________________________ 
Cmpd. 
G R.sup.8 
R.sup.9 R.sup.10 
R.sup.11 
R.sup.12 
__________________________________________________________________________ 
II-1 
H C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
H C.sub.6 H.sub.5 
N(CH.sub.3).sub.2 
II-2 
H CH.sub.3 
CH.sub.3 H C.sub.6 H.sub.5 
N(CH.sub.3).sub.2 
II-3 
H n-C.sub.4 H.sub.9 
n-C.sub.4 H.sub.9 
H C.sub.6 H.sub.5 
N(CH.sub.3).sub.2 
II-4 
3-CH.sub.3 
C.sub.2 H.sub.5 
CF.sub.3 CH.sub.2 O.sub.2 CCH.sub.2 
H C.sub.6 H.sub.5 
N(CH.sub.3).sub.2 
II-5 
H 
##STR20## H C.sub.6 H.sub.5 
N(CH.sub.3).sub.2 
II-6 
H C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
H C.sub.6 H.sub.5 
NHC.sub.6 H.sub.5 
II-7 
H C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
H C.sub.6 H.sub.5 
##STR21## 
II-8 
H C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
H C.sub.6 H.sub.5 
##STR22## 
II-9 
H C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
H C.sub.6 H.sub.5 
NHCH.sub.3 
II-10 
H C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
H C.sub.6 H.sub.5 
N(C.sub.2 H.sub.5)(C.sub.6 H.sub.5) 
2 
II-11 
3-OCH.sub.3 
C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
H C.sub.6 H.sub.5 
N(CH.sub.3).sub.2 
II-12 
H n-C.sub.4 H.sub.9 
n-C.sub.4 H.sub.9 
H C.sub.6 H.sub.5 
OC.sub.2 H.sub.5 
II-13 
3-Cl CH.sub.3 
C.sub.2 H.sub.5 O.sub.2 CCH.sub.2 
H C.sub.10 H.sub.9 
N(CH.sub.3).sub.2 
II-14 
H 
##STR23## H 4-ClC.sub.6 H.sub.4 
OCH.sub.3 
II-15 
3-CH.sub.3 
ClC.sub.2 H.sub.4 
ClC.sub.2 H.sub.4 
H CH.sub.2 C.sub.6 H.sub.5 
OC.sub.6 H.sub.5 
II-16 
3-C.sub.2 H.sub.5 
C.sub.6 H.sub.5 CH.sub.2 
C.sub.2 H.sub.5 
H CH.sub.3 
N(CH.sub.3).sub.2 
II-17 
2,5-(OCH.sub.3).sub.2 
CH.sub.3 
CH.sub.3 H 3,5-(Cl).sub.2C.sub.6 H.sub.3 
NHCH.sub.3 
II-18 
H CH.sub.3 
CH.sub.3 CO.sub.2 C.sub.2 H.sub.5 
C.sub.6 H.sub.5 
N(CH.sub.3).sub.2 
II-19 
H CH.sub.3 
CH.sub.3 Cl C.sub.6 H.sub.5 
N(CH.sub.3).sub.2 
II-20 
3-CH.sub.3 
C.sub.2 H.sub.5 
C.sub.6 H.sub.5 CH.sub.2 
H C.sub.6 H.sub.5 
OC.sub.2 H.sub.5 
II-21 
H C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
H C.sub.6 H.sub.5 
OC.sub.3 H.sub.7 -i 
II-22 
3-CH.sub.3 
C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
H C.sub.6 H.sub.5 
OC.sub.2 H.sub.5 
II-23 
##STR24## 
II-24 
##STR25## 
II-25 
##STR26## 
II-26 
##STR27## 
II-27 
##STR28## 
II-28 
##STR29## 
II-29 
##STR30## 
II-30 
##STR31## 
__________________________________________________________________________ 
In a preferred embodiment for compounds according to formula III employed 
in the invention, R.sup.15 and R.sup.16 are each ethyl, X is OCH.sub.3, J 
is CO, R.sup.17 and R.sup.18 are each CH.sub.3, and R.sup.19 is C.sub.4 
H.sub.9 -t. In another preferred embodiment of the invention, R.sup.15 and 
R.sup.16 are each ethyl, X is OCH.sub.3, J is CO, R.sup.17 is CH.sub.3, 
R.sup.18 is CH.sub.2 CHOHCH.sub.3, and R.sup.19 is C.sub.4 H.sub.9 -t. 
The compounds of formula III above employed in the invention may be 
prepared by any of the processes disclosed in U.S. Pat. No. 3,336,285, BR 
1,566,985, UK 1,531,071 and Dyes and Pigments, Vol 3, 81 (1982), the 
disclosures of which are hereby incorporated by reference. 
Magenta dyes included within the scope of formula III include the 
following: 
__________________________________________________________________________ 
##STR32## 
__________________________________________________________________________ 
Dye R.sup.15 R.sup.16 R.sup.17 
R.sup.18 R.sup.19 
X J 
__________________________________________________________________________ 
III-1 
C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
CH.sub.3 
CH.sub.3 C.sub.4 H.sub.9 -t 
OCH.sub.3 
CO 
III-2 
C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
CH.sub.3 
CH.sub.2 CHOHCH.sub.3 
C.sub.4 H.sub.9 -t 
OCH.sub.3 
CO 
III-3 
C.sub.3 H.sub.7 
C.sub.3 H.sub.7 
CH.sub.3 
CH.sub.3 C.sub.4 H.sub.9 -t 
OCH.sub.3 
CO 
III-4 
C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
C.sub.4 H.sub.9 -t 
CH.sub.3 CH.sub.3 
OCH.sub.3 
CO 
III-5 
C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
CH.sub.3 
C.sub.2 H.sub.5 
C.sub.4 H.sub.9 -t 
OC.sub.2 H.sub.5 
SO.sub.2 
III-6 
C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
CH.sub.3 CH.sub.3 
OC.sub.2 H.sub.5 
CO 
III-7 
C.sub.2 H.sub.5 
C.sub.3 H.sub.7 
CH.sub.3 
CH.sub.3 C.sub.4 H.sub.9 -t 
OCH.sub.3 
CO 
III-8 
C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
CH.sub.3 
CH.sub.3 C.sub.4 H.sub.9 -t 
OCH.sub.3 
CO.sub.2 
III-9 
C.sub.2 H.sub.5 
C.sub.2 H.sub.5 
C.sub.6 H.sub.5 
C.sub.3 H.sub.7 
C.sub.4 H.sub.9 -t 
OC.sub.2 H.sub.5 
SO.sub.2 
III-10 
CH.sub.2CHCH.sub.2 
CH.sub.2CHCH.sub.2 
CH.sub.3 
CH.sub.2 C.sub.6 H.sub.5 
C.sub.4 H.sub.9 -t 
OCH.sub.3 
CO 
III-11 
C.sub.3 H.sub.7 
C.sub.3 H.sub.7 
C.sub.2 H.sub.5 
CH.sub.2 CN 
CN OC.sub.3 H.sub.7 
CO 
III-12 
C.sub.3 H.sub.7 
C.sub.3 H.sub.7 
C.sub.2 H.sub.5 
C.sub.6 H.sub.5 
CH.sub.3 
OC.sub.3 H.sub.7 
SO.sub.2 
III-13 
##STR33## 
III-14 
##STR34## 
III-15 
##STR35## 
III-16 
##STR36## 
__________________________________________________________________________ 
The use of dye mixtures in the dye-donor of the invention permits a wide 
selection of hue and color that enables a close hue match to a variety of 
printing inks and also permits easy transfer of images one or more times 
to a receiver if desired. The use of dyes also allows easy modification of 
image density to any desired level. The dyes of the dye-donor element of 
the invention may be used at a coverage of from about 0.05 to about 1 
g/m.sup.2. 
The dyes in the dye-donor of the invention are dispersed in a polymeric 
binder such as a cellulose derivative, e.g., cellulose acetate hydrogen 
phthalate, cellulose acetate, cellulose acetate propionate, cellulose 
acetate butyrate, cellulose triacetate or any of the materials described 
in U.S. Pat. No. 4,700,207; a polycarbonate; polyvinyl acetate; 
poly(styrene-co-acrylonitrile); a poly(sulfone) or a poly(phenylene 
oxide). The binder may be used at a coverage of from about 0.1 to about 5 
g/m.sup.2. 
The dye layer of the dye-donor element may be coated on the support or 
printed theron by a printing technique such as a gravure process. 
Any material can be used as the support for the dye-donor element of the 
invention provided it is dimensionally stable and can withstand the heat 
of the laser or thermal head. Such materials include polyesters such as 
poly(ethylene terephthalate); polyamides; polycarbonates; celulose esters 
such as cellulose acetate; fluorine polymers such as polyvinylidene 
fluoride or poly(tetrafluoroethylene-co-hexafluoropropylene); polyethers 
such as polyoxymethylene; polyacetals; polyolefins such as polystyrene, 
polyethylene, polropylene or methylpentene polymers; and polyimides such 
as polyimide-amides and polyether-imides. The support generally has a 
thickness of from about 5 to about 200 .mu.m. It may also be coated with a 
subbing layer, if desired, such as those materials described in U.S. Pat. 
No(s). 4,695,288 or 4,737,486. 
The reverse side of the dye-donor element may be coated with a slipping 
layer to prevent the printing head from sticking to the dye-donor element. 
Such a slipping layer would comprise either a solid or liquid lubricating 
material or mixtures thereof, with or without a polymeric binder or a 
surface active agent. Preferred lubricating materials include oils or 
semi-crystalline organic solids that melt below 100.degree. C. such as 
poly(vinyl stearate), beeswax, perfluorinated alkyl ester polyethers, 
poly(capro-lactone), silicone oil, poly(tetrafluoroethylene), carbowax, 
poly(ethylene glycols), or any of those materials disclosed in U.S. Pat. 
No(s). 4,717,711; 4,717,712; 4,737,485; and 4,738,950. Suitable polymeric 
binders for the slipping layer include poly(vinyl alcohol-co-butyral), 
poly(vinyl alcohol-co-acetal), poly(styree), poly(vinyl acetate), 
cellulose acetate butyrate, cellulose acetate propionate, cellulose 
acetate or ethyl cellulose. 
The amount of the lubricating material to be used in the slipping layer 
depends largely on the type of lubricating material, but is generally in 
the range of about 0.001 to about 2 g/m.sup.2. If a polymeric binder is 
employed, the lubricating material is present in the range of 0.1 to 50 
weight %, preferably 0.5 to 40, of the polymeric binder employed. 
The dye-receiving element that is used with the dye-donor element of the 
invention usually comprises a support having thereon a dye image-receiving 
layer. The support may be a transparent film such as a poly(ether 
sulfone), a polyimide, a cellulose ester such as cellulose acetate, a 
poly(vinyl alcohol-co-acetal) or a poly(ethylene terephthalate). The 
support for the dye-receiving element may also be reflective such as 
baryta-coated paper, polyethylene-coated paper, an ivory paper, a 
condenser paper or a synthetic paper such as duPont Tyvek.RTM.. Pigmented 
supports such as white polyester (transparent polyester with white pigment 
incorporated therein) may also be used. 
The dye image-receiving layer may comprise, for example, a polycarbonate, a 
polyurethane, a polyester, polyvinyl chloride, 
poly(styrene-co-acrylonitrile), poly(caprolactone), a poly(vinyl acetal) 
such as poly(vinyl alcohol-co-butyral), poly(vinyl alcohol-co-benzal), 
poly(vinyl alcohol-co-acetal) or mixtures thereof. The dye image-receiving 
layer may be present in any amount which is effective for the intended 
purpose. In general, good results have been obtained at a concentration of 
from about 1 to about 5 g/m.sup.2. 
As noted above, the dye-donor elements of the invention are used to form a 
dye transfer image. Such a process comprises imagewise-heating a dye-donor 
element as described above and transferring a dye image to a dye-receiving 
element to form the dye transfer image. 
The dye-donor element of the invention may be used in sheet form or in a 
continuous roll or ribbon. If a continuous roll or ribbon is employed, it 
may have only the dyes thereon as described above or may have alternating 
areas of other different dyes or combinations, such as sublimable cyan 
and/or yellow and/or black or other dyes. Such dyes are disclosed in U.S. 
Pat. No. 4,541,830, the disclosure of which is hereby incorporated by 
reference. Thus, one-, two-, three- or four-color elements (or higher 
numbers also) are included within the scope of the invention. 
Thermal printing heads which can be used to transfer dye from the dye-donor 
elements of the invention are available commercially. There can be 
employed, for example, a Fujitsu Thermal Head (FTP-040 MCSOO1), a TDK 
Thermal Head F415 HH7-1089 or a Rohm Thermal Head KE 2008-F3. 
A laser may also be used to transfer dye from the dye-donor elements of the 
invention. When a laser is used, it is preferred to use a diode laser 
since it offers substantial advantages in terms of its small size, low 
cost, stability, reliability, ruggedness, and ease of modulation. In 
practice, before any laser can be used to heat a dye-donor element, the 
element must contain an infrared-absorbing material, such as carbon black, 
cyanine infrared absorbing dyes as described in DeBoer application Ser. 
No. 463,095, filed Jan. 10, 1990, or other materials as described in the 
following U.S. application Ser. No(s). 366,970, 367,062, 366,967, 366,968, 
366,969, 367,064, 367,061, 369,494, 366,952, 369,493, 369,492, and 
369,491, the disclosures of which are hereby incorporated by reference. 
The laser radiation is then absorbed into the dye layer and converted to 
heat by a molecular process known as internal conversion. Thus, the 
construction of a useful dye layer will depend not only on the hue, 
transferability and intensity of the image dyes, but also on the ability 
of the dye layer to absorb the radiation and convert it to heat. 
Lasers which can be used to transfer dye from dye-donors employed in the 
invention are available commercially. There can be employed, for example, 
Laser Model SDL-2420-H2 from Spectra Diode Labs, or Laser Model SLD 304 
V/W from Sony Corp. 
A thermal printer which uses the laser described above to form an image on 
a thermal print medium is described and claimed in copending U.S. 
application Ser. No. 451,656 of Baek and DeBoer, filed Dec. 18, 1989, the 
disclosure of which is hereby incorporated by reference. 
Spacer beads may be employed in a separate layer over the dye layer of the 
dye-donor in the above-described laser process in order to separate the 
dye-donor from the dye-receiver during dye transfer, thereby increasing 
the uniformity and density of the transferred image. That invention is 
more fully described in U.S. Pat. No. 4,772,582, the disclosure of which 
is hereby incorporated by reference. Alternatively, the spacer beads may 
be employed in the receiving layer of the dye-receiver as described in 
U.S. Pat. No. 4,876,235, the disclosure of which is hereby incorporated by 
reference. The spacer beads may be coated with a polymeric binder if 
desired. 
The use of an interadiate receiver with subsequent retransfer to a second 
receiving element may also be employed in the invention. A multitude of 
different substrates can be used to prepare the color proof (the second 
receiver) which is preferably the same substrate used for the printing 
press run. Thus, this one intermediate receiver can be optimized for 
efficient dye uptake without de-smearing or crystallization. 
Examples of substrates which may be used for the second receiving element 
(color proof) include the following: Flo Kote Cove.RTM. (S. D. Warren 
Co.), Champion Textweb.RTM. (Champion Paper Co.), Quintessence Gloss.RTM. 
(Potlatch Inc.), Vintage Gloss; (Potlatch Inc.), Khrome Kote.RTM. 
(Champion Paper Co.), Co; Consolith Gloss.RTM. (Consolidated Papers Co.), 
Ad-Proof Paper.RTM. (Appleton Papers, Inc.) and Mountie Matte (Potlatch 
Inc.). 
As noted above, after the dye image is obtained on a first dye-receiving 
element, it is retransferred to a second dye image-receiving element. This 
can be accomplished, for example, by passing the two receivers between a 
pair of heated rollers. Other methods of retransferring the dye image 
could also be used such as using a heated platen, use of pressure and 
heat, external heating, etc. 
Also as noted above, in making a color proof, a set of electrical signals 
is generated which is representative of the shape and color of an original 
image. This can be done, for example, by scanning an original image, 
filtering the image to separate it into the desired additive primary 
colors-red, blue and green, and then converting the light energy into 
electrical energy. The electrical signals are then modified by computer to 
form the color separation data which is used to form a halftone color 
proof. Instead of scanning an original object to obtain the electrical 
signals, the signals may also be generated by computer. This process is 
described more fully in Graphic Arts Manual, Janet Field ed., Arno Press, 
New York 1980 (p. 358ff), the disclosure of which is hereby incorporated 
by reference. 
A thermal dye transfer assemblage of the invention comprises 
a) a dye-donor element as described above, and 
b) a dye-receiving element as described above, the dye-receiving element 
being in a superposed relationship with the dye-donor element so that the 
dye layer of the donor element is in contact with the dye image-receiving 
layer of the receiving element. 
The above assemblage comprising these two elements may be preassembled as 
an integral unit when a monochrome image is to be obtained. This may be 
done by temporarily adhering the two elements together at their margins. 
After transfer, the dye-receiving element is then peeled apart to reveal 
the dye transfer image. 
When a three-color image is to be obtained, the above assemblage is formed 
three times using different dye-donor elements. After the first dye is 
transferred, the elements are peeled apart. A second dye-donor element (or 
another area of the donor element with a different dye area) is then 
brought in register with the dye-receiving element and the process 
repeated. The third color is obtained in the same manner.

The following examples are provided to illustrate the invention. 
EXAMPLE 1 SYNTHESIS OF COMPOUND 1 
A. Synthesis of 2-phenyl-1,1,3-tricyano-propene (intermediate for Compound 
1) 
A mixture of benzoylacetonitrile (9.94 g, 0.0685 mole), malononitrile (11.3 
g, 0.17 mole), ammonium acetate (5.4 g, 0.07 mole) and ethanol (100 mL) 
was heated at reflux for 1.5 hours. After cooling to room temperature, the 
reaction mixture was diluted with water (50 mL) and concentrated 
hydrochloric acid (7.5 mL) was added dropwise over 5 minutes. The 
resulting precipitate was collected by filtration and washed with water 
and ligroin. The yield was 10.0 g (76%), m.p. 92.degree.-98.degree. C. 
B. Synthesis of Compound 1: 
2-phenyl-1,1,3-tricyano-3-(4-diethylamino-2-methylphenylimino)-propene 
##STR37## 
A mixture of the phenyltricyanopropene above (0.58 g, 0.003 mole) and 
2-amino-5-diethylaminotoluene hydrochloride (0.64 g, 0.003 mole) in a 
solution of methanol (30 mL) and water (10 mL) was treated with 
concentrated ammonium hydroxide (1.8 mL). To this mixture was slowly added 
a solution of potassium ferricyanide (4.94 g, 0.015 ,le) in water (20 mL), 
keeping the temperature below 20.degree. C. with external cooling. After 
stirring for 2 hours, the reaction mixture was diluted with water (100 mL) 
and the resulting precipitate was collected by filtration and washed well 
with water. The crude dye was crystallized from methanol to yield 0.85 g 
(81%) of a dark green powder. The dye had a lambda max of 604 nm with a 
molar extinction coefficient of 44,200 (in acetone solution). 
EXAMPLE 2 
A black dye-donor element was prepared by coating on a 100 .mu.m 
poly(ethylene terephthalate) support: 
1) a subbing layer of oly(acrylonitrile-co-vinylidene chloride-co-acrylic 
acid) (0.054 g/m.sup.2) (14:79:7 wt. ratio); and 
2) a dye layer containing a mixture of cyan dye 8, yellow dye II-1 and 
magenta dye III-2 illustrated above, (each at 0.22 g/m.sup.2) and the 
cyanine infrared absorbing dye illustrated below (0.054 g/m.sup.2) in a 
cellulose acetate propionate binder (2.5% acetyl, 45% propionyl) (0.27 
g/m.sup.2) coated from dichloromethane. 
Comparison dye-donors using a mixture of cyan, yellow and magenta dyes of 
the prior art as identified below, at a total noverage of 0.66 g/m.sup.2, 
were also prepared. 
Cyanine Infrared Absorbing Dye 
##STR38## 
An intermediate dye-receiving element was prepared by coating on an 
unsubbed 100 .mu.m thick poly(ethylene terephthalate) support a layer of 
crosslinked poly(styrene-co-divinylbenzene) beads (12 micron average 
diameter) (0.11 g/m.sup.2), triethanolamine (0.09 g/m.sup.2) and 
DC-510.RTM. Silicone Fluid (Dow Corning Company) (0.01 g/m.sup.2) in a 
Butar 76 binder, a poly(vinyl alcohol-co-butyral), (Monsanto Company) (4.0 
g/m.sup.2) from 1,1,2-trichloroethane and dichloromethane. 
Single color black images were printed as described below from dye-donors 
onto a receiver using a laser imaging device as described in U.S. Pat. No. 
4,876,235. The laser imaging device consisted of a single diode laser 
connected to a lens assembly mounted on a translation stage and focused 
onto the dye-donor layer. 
The dye-receiving element was secured to the drum of the diode laser 
imaging device with the receiving layer facing out. The dye-donor element 
was secured in face-to-face contact with the receiving element. 
The diode laser used was a Spectra Diode Labs No. SDL-2430-H2, having an 
integral, attached optical fiber for the output of the laser beam, with a 
wavelength of 816 nm and a nominal power output of 250 milliwatts at the 
end of the optical fiber. The cleaved face of the optical fiber (100 
microns core diameter) was imaged onto the plane of the dye-donor with a 
0.33 magnification lens assembly mounted on a translation stage giving a 
nominal spot size of 33 microns and a measured power output at the focal 
plane of 115 milliwatts. 
The drum, 312 mm in circumference, was rotated at 500 rpm and the imaging 
electronics were activated. The translation stage was incrementally 
advanced across the dye-donor by means of a lead screw turned by a 
microstepping motor, to give a center-to-center line distance of 14 
microns (714 lines per centimeter, or 1800 lines per inch). For a 
continuous tone stepped image, the current supplied to the laser was 
modulated from full power to 16% power in 4% increments. 
After the laser had scanned approximately 12 mm, the laser exposing device 
was stopped and the intermediate receiver was separated from the dye 
donor. The intermediate receiver containing the stepped dye image was 
laminated to Ad-Proof Paper.RTM. (Appleton Papers, Inc.) 60 pound stock 
paper by passage through a pair of rubber rollers heated to 120.degree. C. 
The polyethylene terephthalate support was then peeled away leaving the 
dye image and polyvinyl alcohol-co-butyral firmly adhered to the paper. 
The paper stock was chosen to represent the substrate used for a printed 
ink image obtained from a printing press. 
The Status T density of each of the stepped images was read using an 
X-Rite.RTM. 418 Densitometer to find the single step image within 0.05 
density unit of the SWOP Color Reference. For the black standard, this 
density was 1.6. 
The a* and b* values of the selected step image of transferred dye-mixture 
was compared to that of the SWOP Color Reference reading on an X-Rite.RTM. 
918 Colorimeter set for D50 illuminant and a 10 degree observer. The L* 
reading was checked to see that it did not differ appreciably from the 
reference. The a* and b* readings were recorded and the distance from the 
SWOP Color Reference calculated as the square root of the sum of 
differences square for a* and b*: 
##EQU1## 
e=experiment (transferred dye) s=SWOP Color Reference 
In addition, the above dye-donors were evaluated for storage stability by 
comparing transmission spectra of the donor before and after incubation at 
50.degree. C./50% RH for 4 days. 
The following results were obtained: 
TABLE 1 
______________________________________ 
Dyes Distance 
Density 
(Weight From @ Storage 
Ratio) a* b* Reference 
500 rpm 
Stability 
______________________________________ 
SWOP 1.5 2.0 
8/II-1/III-2 
0.5 -0.5 2.5 1.6 good 
(33:33:34) 
8/II-1/III-1 
0.5 1 1 1.8 good 
(37:26:37) 
8/II-22/III-1 
3.5 1 2 1.4 good 
(37:23:40) 
1/II-1/III-2 
2 -3 5 1.7 good 
(33:33:34) 
1/II-22/III-2 
5 -2 5 1.5 good 
(33:28:39) 
Control 1.sup.a 
-1.2.sup.b 
-5.4.sup.b 
8.0 0.8 good 
(46:27:27) 
Control 2.sup.c 
-2.4 -1.5 5.5 1.6 .sup. poor.sup.d 
(54:21:25) 
______________________________________ 
.sup.a Similar to Table C17 from U.S. Pat. No. 4,923,846, a mixture of 
Solvent Blue 36, Solvent Red 19 and Foron Brilliant Yellow S6GL 
(structures below). 
.sup.b The drum speed was reduced to 400 rpm so that sufficient density 
could be obtained to allow a valid hue comparison. 
.sup.c Similar to Example 1 of U.S. Pat. No. 4,186,435 (dye structures 
below). 
.sup.d At room temperature after two days, some of the magenta dye 
sublimed out of the coating onto an adjacent piece of paper. In addition, 
after incubation, at least 75% of the absorption due to the cyan dye was 
lost. 
##STR39## 
The above results indicate that by using a mixture of cyan, magenta and 
yellow dyes according to the invention in an appropriate ratio, a hue 
closely corresponding to that of the black SWOP Color Reference was 
obtained, in comparison to the controls of the prior art which were 
further away from the SWOP Color Reference. 
Although Control 2 yields high transfer density and a reasonable color 
match, the storage stability was poor as noted above. Although Control 1 
had good storage stability, it was difficult to obtain useful densities. 
The invention has been described in detail with particular reference to 
preferred embodiments thereof, but it will be understood that variations 
and modifications can be effected within the spirit and scope of the 
invention.