General Electric Company

Videojet Systems International, Inc.

Beatrice M Nicholas

Alan Mosley

Michael G Clark

Cyril Hilsum

Carolyn Bowry

Nicholas A Davies

A hot melt ink comprising, a eutectic composition and an image-forming agent, wherein the melting point of the eutectic composition is from about 80.degree. C. to about 130.degree. C. and the compounds present in the eutectic compositions have melting points of at least about 100.degree. C. Also disclosed is a method for ink jet printing comprising:

Eutectic compositions for hot melt jet inks

A device for indicating whether a rise in temperature above a predetermined value has occurred includes a support member, such as a label, on which a temperature-sensitive material is deposited. The material includes a large number of fracturable microcapsules containing a medium which changes from a solid state to a liquid state at the predetermined temperature value. The viscosity of the medium in its liquid state and the material of the support member are chosen such that the distance d.sub.1 by which the medium flows across the support member after the fracturing of the microcapsules so as to activate the device is indicative of the time between activation of the device and cooling of the device to below the predetermined temperature value. If the temperature is subsequently allowed to rise above the predetermined value, the medium will again assume its liquid state and will flow further across the support member, reaching a distance of, say, d.sub.2, thus indicating that the rise in temperature has occurred. The material may be printed on the label as a bar code, so that any rise above the predetermined temperature level will be indicated by distortion of the bar code which renders it unreadable.

Temperature-sensitive materials and devices

A liquid crystal device comprises a ferroelectric smectic phase liquid crystal enclosed between two surfaces, the surfaces being such that the directors of the liquid crystal adjacent the surfaces are not parallel to the surfaces. The directors adjacent one of the surfaces are not parallel to the directors adjacent the other surface, the liquid crystal cone angle being equal to half the angle between a pair of directors each adjacent a different one of the surfaces.

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Tring, United Kingdom

Beatrice M Nicholas