US4720449A — Thermal imaging method

Claim 1

Independent Claim 128 words

A heat-sensitive element comprising a support carrying at least one imaging layer of a substantially colorless di- or triarylmethane imaging compound possessing within its di- or triarylmethane structure an aryl group substituted in the ortho position to the meso carbon atom with a moiety ring-closed on the meso carbon atom to form a 5- or 6-membered ring, said moiety possessing a nitrogen atom bonded directly to said meso carbon atom and said nitrogen atom being bound to a group with a masked acyl substituent that undergoes fragmentation upon heating to liberate the acyl group for effecting intramolecular acylation of said nitrogen atom to form a new group in the ortho position that cannot bond to the meso carbon atom whereby said di- or triarylmethane compound is rendered colored.

Claim 2

Dependent Claim 128 words

A heat-sensitive element comprising a support carrying at least one imaging layer of a substantially colorless di- or triarylmethane imaging compound possessing within its di- or triarylmethane structure an aryl group substituted in the ortho position to the meso carbon atom with a moiety ring-closed on the meso carbon atom to form a 5- or 6-membered ring, said moiety possessing a nitrogen atom bonded directly to said meso carbon atom and said nitrogen atom being bound to a group with a masked acyl substituent that undergoes fragmentation upon heating to liberate the acyl group for effecting intramolecular acylation of said nitrogen atom to form a new group in the ortho position that cannot bond to the meso carbon atom whereby said di- or triarylmethane compound is rendered colored.

Claim 3

Dependent Claim 40 words

A heat-sensitive element as defined in claim 1 wherein an infra-red absorber is associated with said imaging layer of colorless imaging compound for absorbing radiation at wavelengths above 700 nm and transferring said absorbed radiation as heat to said compound.

Claim 4

Dependent Claim 18 words

A heat-sensitive element as defined in claim 1 wherein said colorless imaging compound upon heating is rendered black.

Claim 5

Dependent Claim 20 words

A heat-sensitive element as defined in claim 1 which comprises at least two said imaging layers of colorless imaging compound.

Claim 6

Dependent Claim 41 words

A heat-sensitive element as defined in claim 3 wherein each said imaging layer of colorless imaging compound has an infra-red absorber associated therewith for absorbing radiation at wavelengths above 700 nm and transferring said absorbed radiation as heat to said compound.

Claim 7

Dependent Claim 27 words

A heat-sensitive element as defined in claim 5 wherein said infra-red absorbers associated with said imaging layers selectively absorb radiation at different predetermined wavelengths above 700 nm.

Claim 8

Dependent Claim 26 words

A heat-sensitive element as defined in claim 5 wherein said infra-red absorbers associated with said imaging layers absorb radiation at the same wavelength above 700 nm.

Claim 9

Dependent Claim 19 words

A heat-sensitive element as defined in claim 5 which additionally includes a thermal isolation layer between adjacent imaging layers.

Claim 10

Dependent Claim 49 words

A heat-sensitive element as defined in claim 8 wherein said support carries an imaging layer of colorless imaging compound for forming a cyan image, an imaging layer of colorless imaging compound for forming a magenta image and an imaging layer of colorless imaging compound for forming a yellow image.

Claim 11

Independent Claim 158 words

A method of thermal imaging which comprises heating imagewise a heat-sensitive element comprising a support carrying at least one imaging layer of a substantially colorless di- or triarylmethane imaging compound possessing within its triarylmethane structure an aryl group substituted in the ortho position to the meso carbon atom with a moiety ring-closed on the meso carbon atom to form a 5- or 6-membered ring, said moiety possessing a nitrogen atom bonded directly to said meso carbon atom and said nitrogen atom being bound to a group with a masked acyl substituent that undergoes fragmentation upon heating to liberate the acyl group for effecting intramolecular acylation of said nitrogen atom to form a new group in the ortho position that cannot bond to the meso carbon atom, said imagewise heating effecting the formation of said new group in the ortho position whereby said di- or triarylmethane compound is rendered colored in an imagewise pattern corresponding to said imagewise heating.

Claim 12

Independent Claim 158 words

A method of thermal imaging which comprises heating imagewise a heat-sensitive element comprising a support carrying at least one imaging layer of a substantially colorless di- or triarylmethane imaging compound possessing within its triarylmethane structure an aryl group substituted in the ortho position to the meso carbon atom with a moiety ring-closed on the meso carbon atom to form a 5- or 6-membered ring, said moiety possessing a nitrogen atom bonded directly to said meso carbon atom and said nitrogen atom being bound to a group with a masked acyl substituent that undergoes fragmentation upon heating to liberate the acyl group for effecting intramolecular acylation of said nitrogen atom to form a new group in the ortho position that cannot bond to the meso carbon atom, said imagewise heating effecting the formation of said new group in the ortho position whereby said di- or triarylmethane compound is rendered colored in an imagewise pattern corresponding to said imagewise heating.

Claim 13

Dependent Claim 62 words

A method of thermal imaging as defined in claim 10 wherein an infra-red absorber is associated with said imaging layer of colorless imaging compound for absorbing radiation at wavelengths above 700 nm and transferring said absorbed radiation as heat to said compound, said layer being heated imagewise by imagewise exposure to infra-red radiation at a wavelength strongly absorbed by said infra-red absorber.

Claim 14

Dependent Claim 37 words

A method of thermal imaging as defined in claim 11 wherein said imaging layer is heated imagewise by imagewise exposure to a laser beam source emitting infra-red radiation at a wavelength strongly absorbed by said infra-red absorber.

Claim 15

Dependent Claim 20 words

A method of thermal imaging as defined in claim 10 wherein said element comprises at least two said imaging layers.

Claim 16

Dependent Claim 24 words

A method of thermal imaging as defined in claim 13 wherein said heat-sensitive element additionally includes a thermal isolation layer between adjacent imaging layers.

Claim 17

Dependent Claim 89 words

A method of thermal imaging as defined in claim 13 wherein an infra-red absorber is associated with each said imaging layer for absorbing radiation at wavelengths above 700 nm and transferring said absorbed radiation as heat to each said colorless imaging compound, said infra-red absorbers associated with said imaging layers selectively asorbing infra-red radiation at different predetermined wavelengths above 700 nm, said imagewise heating being effected by imagewise exposure to a plurality of laser beam sources emitting infra-red radiation at the respective wavelengths selectively absorbed by said infra-red absorbers.

Claim 18

Dependent Claim 91 words

A method of thermal imaging as defined in claim 13 wherein an infra-red absorber is associated with each said imaging layer for absorbing radiation at wavelengths above 700 nm and transferring said absorbed radiation as heat to each said colorless imaging compound, said infra-red absorbers associated with said imaging layers absorbing infra-red radiation at the same wavelength or at different wavelengths above 700 nm, said imaging layers being heated imagewise by adjusting the depth of focus of a laser beam source emitting radiation at the wavelength absorbed by said infra-red absorber.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1991-01-18	1991-07-20	1992-01-19	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1995-01-18	1995-07-20	1996-01-19	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1999-01-18	1999-07-20	2000-01-19	$7700.00	Window Closed / Lapsed

Thermal imaging method

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