System for prevention of unauthorized copying
First Claim
1. A web having phosphor particles uniformly distributed on at least one outer surface of said web, said phosphor particles being substantially white or colorless under ambient room light illumination and which upon excitation by ultraviolet light having a wavelength between about 200 nanometers and about 400 nanometers phosphoresces to emit visible blue radiation having a wavelength longer than said ultraviolet light wavelength, said visible blue radiation being between about 400 nanometers and about 500 nanometers and being detectable on a period of at least 500 microseconds following termination of ultraviolet excitation.
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Accused Products
Abstract
A web having phosphor particles uniformly distributed on at least one outer surface of the web, the phosphor particles being substantially white or colorless under ambient room light illumination and which upon excitation by ultraviolet light phosphoresces to emit visible radiation having a wavelength between about 400 nanometers and about 500 nanometers for a detactable period after ultraviolet excitation. Imaged webs having phosphor particles uniformly distributed on at least one outer surface thereof may be employed in an imaging process the steps of illuminating the outer surface bearing an image with ultraviolet light during an electrostatographic imaging cycle to cause the phosphor particles to emit visible light, terminating the illumination of the outer surface bearing the image with the ultraviolet light, detecting the visible light emitted by the phosphor particles and altering at least one element of the electrostatographic imaging cycle in response to the detection of the visible light whereby the electrostatographic imaging cycle is disabled.
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Citations
16 Claims
- 1. A web having phosphor particles uniformly distributed on at least one outer surface of said web, said phosphor particles being substantially white or colorless under ambient room light illumination and which upon excitation by ultraviolet light having a wavelength between about 200 nanometers and about 400 nanometers phosphoresces to emit visible blue radiation having a wavelength longer than said ultraviolet light wavelength, said visible blue radiation being between about 400 nanometers and about 500 nanometers and being detectable on a period of at least 500 microseconds following termination of ultraviolet excitation.
- 8. An imaging process comprising providing a web having phosphor particles uniformly distributed on at least one outer surface of said web, said phosphor particles being substantially white or colorless under ambient room light illumination and which upon excitation by ultraviolet light phosphoresces to emit visible radiation for a detectable period after ultraviolet light excitation, said outer surface bearing a light absorbing image, illuminating said outer surface bearing said image with ultraviolet light during an electrostatographic imaging cycle to cause said phosphor particles to emit visible light, terminating said illumination of said outer surface bearing said image with said ultraviolet light, detecting said visible light emitted by said phosphor particles after terminating said illumination, and altering at least one element of said electrostatographic imaging cycle in response to the detection of said visible light whereby said electrostatographic imaging cycle is disabled.
- 14. Imaging apparatus comprising means to support a web having phosphor particles uniformly distributed on at least one outer surface of said web, said phosphor particles being capable of phosphorescence to emit visible radiation upon excitation by ultraviolet light, means to apply ultraviolet light to said phosphor particles, means to terminate application of said ultraviolet light to said phosphor particles, means adapted to detect said visible radiation emitted by said phosphor particles after said application of said ultraviolet light to said phosphor particles is terminated, and means to disable operation of said imaging apparatus upon detection of said visible radiation emitted by said phosphor particles after said application of said ultraviolet light to said phosphor particles is terminated.
Specification