Security liquid electrostatic ink composition

Patent metadata

Field	Value
Publication number	US-2019033742-A1
Application number	US-201616072470-A
Country	US
Kind code	A1
Filing date	Mar 10, 2016
Priority date	Mar 10, 2016
Publication date	Jan 31, 2019
Grant date	—

Abstract

Described herein is a LEP ink composition comprising a luminescent component, a resin; and a carrier liquid security liquid electrostatic ink composition for printing a security image.

First claim

1 . A security liquid electrophotographic (LEP) ink composition comprising:
a luminescent component; a resin; and a carrier liquid,
wherein the LEP ink composition is colourless when viewed under visible light and luminesces to emit visible light on exposure to IR light.

2 . A LEP ink composition according to claim 1 , wherein the luminescent component comprises a transition metal containing material or a rare-earth containing material.

3 . A LEP ink composition according to claim 2 , wherein the luminescent component comprises a transition metal complex and/or a lanthanide complex.

4 . A LEP ink composition according to claim 1 , wherein the luminescent material comprises a transition metal or rare-earth oxysulfide, oxide, hydroxide, hydride, halide or combinations thereof.

5 . A LEP ink composition according to claim 1 , wherein the luminescent material absorbs IR light having a wavelength in the range of 940 nm to 1060 nm.

6 . A LEP ink composition according to claim 1 , wherein the luminescent material emits visible light on exposure to IR light having an intensity above a threshold value.

7 . A LEP ink composition according to claim 6 , wherein the threshold value for the intensity of IR light is 1 mW/mm 2 or greater.

8 . A LEP ink composition according to claim 1 which forms a LEP image which is invisible to the human eye.

9 . A LEP ink composition according to claim 1 comprising a charge director.

10 . A LEP ink composition according to claim 1 , wherein the resin comprises a copolymer of an alkylene monomer and an acrylic acid monomer or a methacrylic acid monomer.

11 . A method of providing a security liquid electrophotographic (LEP) ink composition, the method comprising:
providing a luminescent component which emits visible light on exposure to IR light; and combining the luminescent component with a resin and a carrier liquid to provide a LEP ink composition which is colourless when viewed under visible light.

12 . A method according to claim 11 , wherein the luminescent component is selected to emit visible light at a pre-selected wavelength on exposure to IR light.

13 . A method according to claim 11 , comprising providing a first luminescent component and a second luminescent component, wherein the first luminescent component and the second luminescent component are selected to provide a LEP ink composition having pre-selected emission spectrum on exposure to IR light.

14 . A method of printing a security LEP image, the method comprising:
providing a LEP ink composition comprising:
a luminescent component which emits visible light on exposure to IR light;
a resin; and
a carrier liquid; and
liquid electrophotographically printing the LEP ink composition onto a print substrate to provide a security LEP image disposed on the print substrate, wherein the security LEP image is invisible to the human eye when viewed under visible light.

15 . A method according to claim 14 , comprising:
providing: a red LEP ink composition comprising a luminescent component which absorbs IR light and emits red light; a green LEP ink composition comprising a luminescent component that absorbs IR light and emits green light; and a blue LEP ink composition comprising a luminescent component which absorbs IR light and emits blue light; and liquid electrophotographically printing the red, green and blue LEP ink compositions onto a print substrate to provide a security LEP image disposed on the print substrate, wherein the security LEP image is invisible to the human eye when viewed under visible light.

Assignees

• Hp Indigo Bv

Inventors

• Cohen Haim
• Grinwald Yaron
• Kornilov Julia
• Avigdor Reut
• Amir Gideon

Classifications

• G03G9/131

  obtained by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• G03G9/122 Primary

  characterised by the colouring agents · CPC title

• G03G9/1355

  Ionic, organic compounds · CPC title

• G03G15/10

  using a liquid developer · CPC title

• G03G15/0121

  for developing · CPC title