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US 7,678,515 B2Granted
Thermally gated photochromic medium
AssigneeXerox Corporation
InventorsKentaro Morimitsu, Tyler Norsten, Gabriel Iftime, Peter Kazmaier
Life of this patent
Estimating the term…
Abstract
The presently disclosed embodiments are directed to image forming mediums useful for reimageable and transient documents. More particularly, the embodiments pertain to an image forming medium comprising thermally gated photochromic materials comprising diarylethene (DAE) photochromes which avoid problems with unwanted reduction in color contrast due to background coloration.
Claims24
An image forming medium, comprising:
- a substrate;
- and
- an imaging layer coated on or impregnated into the substrate, wherein the imaging layer comprises an imaging composition that exhibits a reversible transition between a colorless state and a colored state and further comprises a thermally gated diarylethene photochromic material dissolved in a solvent or polymeric binder, and further wherein the diarylethene photochromic material comprises a diarylethene molecule represented by a general formula selected from the group consisting of
- wherein in formula (I) each X independently represents a hydrogen, an alkyl chain having 1 to 20 carbon atoms, cyano, fluorine, bromine, chlorine or an iodine atom;
- in formula (II) X represents S or O;
- in formula (IV) X represents S, O or C═O, and Y represents O, CH2 or C═O;
- in formula (V) Y represents CH2 or C═O;
- in formula (VI), X represents CH or N;
- in formula (VII), Y represents CH2 or C═O;
- in formula (VIII), X represents S or O;
- and in formulas (II), (III), (V) and (VIII), R1-R3 represents an alkyl group wherein the alkyl group can be a straight, branched or cyclic, substituted or unsubstituted, from 1 to about 40 carbon atoms, an substituted or unsubstituted aromatic or heteroaromatic group;
- further wherein:
- A represents a formula selected from the group consisting of (g), (h) and (i) as shown below;
- and
- B represents a formula selected from the group consisting of (j), (k) and (l) as shown below
- and further wherein:
- R4 and R8 independently represent hydrogen bond forming groups selected from the group consisting of a carboxy, hydroxy, amino, amino acid, amide, and peptide group which form pairwise hydrogen bonds with each other;
- R5 and R9 independently represent a hydrogen atom, a halogen atom, an aryl group, a substituted or unsubstituted alkylaryl group wherein hetero atoms either may or may not be present in the alkyl portion of the alkylaryl group or the aryl portion of the alkylaryl group, a saturated or unsaturated hydrocarbons which is optionally substituted, a fluoroalkyl group, a cyano group, a formyl group, or a carboxy group;
- R6 and R10 independently represent a hydrogen atom, an alkyl group, a halogen atom, an alkoxy group, a fluoroalkyl group, a cyano group, an aryl group, or a substituted alkylaryl group;
- R7 and R11 independently represent an alkyl group, an aryl group, or an alkylaryl group including substituted alkylaryl groups, unsubstituted alkylaryl groups, and wherein hetero atoms either may or may not be present in the alkyl portion of the alkylaryl group or the aryl portion of the alkylaryl;
- Q represents direct bonds, aryl, alkylaryl, heteroaryl, heteroalkylaryl, straight, branched or cyclic, hetero substituted or unsubstituted, alkyl groups from 1 to about 10 carbon atoms, alkenyl, alkynyl, or fluoroalkyl groups, wherein hetero atoms either may or may not be present and are optionally substituted;
- and
- U and Z each independently represent sulfur or oxygen atoms.
20 more elements
An image forming medium, comprising:
- a substrate;
- and
- an imaging layer coated on or impregnated into the substrate, wherein the imaging layer comprises an imaging composition that exhibits a reversible transition between a colorless state and a colored state and further comprises a thermally gated photochromic material dissolved in a solvent or polymeric binder, the thermally gated photochromic material being a diarylethene molecule having hydrogen bond forming groups bonded together through hydrogen bonds, and further wherein the hydrogen bond forming groups are attached at phenyl groups at both ends of the diarylethene molecule or are attached at 2-positions of thiophene moieties at both ends of the diarylethene molecule.
A method for forming an image, comprising:
- providing an image forming medium comprising
- a substrate, and
- an imaging layer coated on or impregnated into the substrate, wherein the imaging layer comprises an imaging composition that exhibits a reversible transition between a colorless state and a colored state and further comprises a thermally gated photochromic material dissolved in a solvent or polymeric binder, the thermally gated photochromic material being a diarylethene molecule represented by a general formula selected from the group consisting of
- wherein in formula (I) each X independently represents a hydrogen, an alkyl chain having 1 to 20 carbon atoms, cyano, fluorine, bromine, chlorine or an iodine atom;
- in formula (II) X represents S or O;
- in formula (IV) X represents S, O or C═O, and Y represents O, CH2 or C═O;
- in formula (V) Y represents CH2 or C═O;
- in formula (VI), X represents CH or N;
- in formula (VII), Y represents CH2 or C═O;
- in formula (VIII), X represents S or O;
- and in formulas (II), (III), (V) and (VIII), R1-R3 represents an alkyl group wherein the alkyl group can be a straight, branched or cyclic, substituted or unsubstituted, from 1 to about 40 carbon atoms, an substituted or unsubstituted aromatic or heteroaromatic group;
- further wherein:
- A represents a formula selected from the group consisting of (g), (h) and (i) as shown below;
- and
- B represents a formula selected from the group consisting of (j), (k) and (l) as shown below
- and further wherein:
- R4 and R8 independently represent hydrogen bond forming groups selected from the group consisting of a carboxy, hydroxy, amino, amino acid, amide, and peptide group which form pairwise hydrogen bonds with each other;
- R5 and R9 independently represent a hydrogen atom, a halogen atom, an aryl group, a substituted or unsubstituted alkylaryl group wherein hetero atoms either may or may not be present in the alkyl portion of the alkylaryl group or the aryl portion of the alkylaryl group, a saturated or unsaturated hydrocarbons which is optionally substituted, a fluoroalkyl group, a cyano group, a formyl group, or a carboxy group;
- R6 and R10 independently represent a hydrogen atom, an alkyl group, a halogen atom, an alkoxy group, a fluoroalkyl group, a cyano group, an aryl group, or a substituted alkylaryl group;
- R7 and R11 independently represent an alkyl group, an aryl group, or an alkylaryl group including substituted alkylaryl groups, unsubstituted alkylaryl groups, and wherein hetero atoms either may or may not be present in the alkyl portion of the alkylaryl group or the aryl portion of the alkylaryl;
- Q represents direct bonds, aryl, alkylaryl, heteroaryl, heteroalkylaryl, straight, branched or cyclic, hetero substituted or unsubstituted, alkyl groups from 1 to about 10 carbon atoms, alkenyl, alkynyl, or fluoroalkyl groups, wherein hetero atoms either may or may not be present and are optionally substituted;
- and
- U and Z each independently represent sulfur or oxygen atoms;
- and
- exposing the image forming medium to ultraviolet irradiation of a first wavelength and heat in an imagewise manner to form a visible image.
22 more elements
Dependencies are inferred from the claim text.