Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G9/00—Developers
  • G03G9/08—Developers with toner particles
  • G03G9/09—Colouring agents for toner particles
  • G03G9/0926—Colouring agents for toner particles characterised by physical or chemical properties

Definitions

• the present invention relates to a conductive monocomponent security toner which fluoresces under UV or black light.
• the invention further relates to an ion deposition type (MIDAX) security toner for use in non-impact printing which fluoresces or becomes visible under UV, black light or other electromagnetic energy, i.e. the non-visible spectrum.
• MIDAX ion deposition type
• Monocomponent toners are toners in which a magnetically attractable material is contained within the toner particles. Thus, a monocomponent toner does not require a magnetic carrier material as does a dual component toner system which uses non magnetic toner particles.
• a variety of prior art toner systems employ fluorescent materials.
• the uses for the fluorescent materials vary widely as does the manner in which the fluorescent material is included within the toner system.
• IBM Technical Disclosure Bulletin Vol. 21, No. 4, September 1978 describes a toner for use in identifying the copy machine from which a copy was produced or for establishing that a particular document is not an original.
• the toner of the IBM Disclosure is for a copy machine and is thus a dual component toner.
• the magnetic carrier material remains within the development section and is used to triboelectrically charge the toner component to provide printing.
• U.S. Patent No. 4,443,527 to Heikens et al. describes a monocomponent toner which is dyed to form a colored toner composition.
• the toner particles comprise a magnetically attractable core.
• a masking layer is then applied to effectively conceal or mask the color of the magnetic core material.
• a coloring material including a fluorescent material is added to cause the toner to produce an image having a color such as red, blue or yellow under ordinary daylight conditions.
• Another object of the present invention to provide a monocomponent conductive toner which fluoresces or becomes visible upon exposure to UV, black light or other electromagnetic radiation in the non-visible spectrum.
• a further object of the invention is to provide a monocomponent conductive toner for use in non-impact printing which fluoresces or becomes visible upon exposure to UV, black light or other electromagnetic radiation in the non-visible spectrum.
• a fluorescent pigment particle is mixed in with the monocomponent toner particle and attaches to the toner particle by cohesive forces.
• the toner When the toner is imaged onto the paper it appears as black lettering and has a normal appearance. Under UV light, black light or other electromagnetic radiation in the non-visible spectrum, the lettering fluoresces.
• the present invention provides a monocomponent conductive toner wherein a fluorescent pigment is mixed therewith, attaching to the toner particles by cohesive forces.
• a fluorescent pigment is mixed therewith, attaching to the toner particles by cohesive forces.
• the present invention adds an important security feature to a monocomponent, conductive toner by fluorescing or becoming visible under UV, black light or other electromagnetic radiation in the non-visible spectrum, without altering the functionality of the toner.
• any tampering or forgery can be easily detected by exposing the document to UV or black light.
• Standard black MIDAX toner may include particles having magnetically attractive material therein, a binder and a pigment. Toner is considered conductive if the bulk resistivity is less than 1010 ohm-cm. Standard black MIDAX toner is conductive, having a resistivity of from about 105 to about 109 ohm-cm.
• MIDAX Intelligent imaging among them MICR (Magnetic Ink Character Recognition) and OCR (Optical Character Recognition). This type of security feature did not heretofor exist with MIDAX Intelligent imaging because standard MIDAX toner does not fluoresce under UV light.
• MICR and OCR are enhanced by using the MIDAX toner of the present invention.
• the toner according to the present invention it would be possible to determine, under UV radiation, whether characters had been tampered with or forged.
• MICR and OCR are enhanced by printing with the toner of the invention on black paper. Thus, characters which would be invisible to the human eye under regular light would be quite vivid and easy to read under UV radiation.
• MIDAX toner On type of MIDAX toner is produced by Coates and is a monocomponent, magnetic conductive toner. This is in contrast to nonconductive or photoconductive toners, such as dual component toners, which require triboelectric charges.
• Conductive toners are toners which conduct electric charge through their mass due to the conductivity of their formulation (i.e., naturally conductive materials that make up the toner).
• Photoconductive toner refers to toners used in a printing process in which a photoconductor is used to form the electronic image. Generally, photoconductive material is material that becomes conductive once illuminated. Once the illumination ceases, it can no longer conduct electricity.
• photoconductive toner processes conduct electric charge triboelectrically (i.e. by constant rubbing and mixing in the toner hopper, the toner exhibits conductivity on its surface).
• the monocomponent toner comprises particles having magnetically attractable material therein.
• This magnetically attractable material may be one single magnetically attractable particle or a binder containing magnetically attractable particles.
• the magnetically attractable particles include materials known for use in monocomponent toners or mixtures thereof including iron, nickel, chromium dioxide, magnetite, gamma-ferrioxide and ferrites.
• the magnetically attractable particles are preferably iron oxide, and more preferably magnetite, and generally have a particle size from about 0.05 ⁇ to about 5.0 ⁇ and more particularly from about 0.1 ⁇ to about 1.0 ⁇ .
• the binder may be selected from any known suitable binder for use in monocomponent toner formulations. Suitable binders include polystyrene, polyvinyl chloride, polyacrylates and polymethacrylates, polyolefins, ethylene vinyl acetate, polyester resins, polyamides, epoxy resins and mixtures thereof. The binder is preferably selected from polyolefins, ethylene vinyl acetate and polyamides.
• the toner particles are mixed with a fluorescent pigment which attaches to the toner particles by a cohesive force.
• the resultant toner appears as black lettering when imaged onto paper and viewed under normal daylight. When viewed under a UV, black light or other electromagnetic radiation in the non-visible spectrum, the lettering fluoresces.
• Fluorescent pigments for use in the present invention include those pigments which will attach to the toner particles without interfering with the conductive properties of the toner required for imaging.
• Suitable fluorescent pigments include LUMOGEN YELLOW S 0790 produced by BASF, Holland, MI. This pigment exhibits a yellow-green fluorescence when exposed to UV light.
• Other pigments can be used that exhibit other colors under suitable electromagnetic radiation having a wave length in the non-visible spectrum, such as alzadine pigment and Pigment Yellow 101 C.I. #48052.
• the fluorescent pigment is mixed with the toner in an amount of from about 0.1 parts to about 10 parts per 100 parts of toner. More preferably, the pigment is added in an amount of from about 0.1 parts to about 5 parts per 100 parts of toner. Most preferably, the pigment is added in an amount of from about 0.9 parts to about 2.5 parts per 100 parts of toner.
• MIDAX printing is a high speed, non-impact printing process whereby a dry monocomponent toner is used to develop an electric image.
• the image is created on a dielectric drum which rotates towards the developing station where the toner is kept to develop the image.
• the developed image is then transfixed to a substrate, such as plain paper, or by pressure.
• the residual toner on the drum is cleaned, and the process repeats with a new image.
• a fluorescent dye has been post added to a standard MIDAX toner.
• the mixer was a type chemical blender with a mixing propeller and a blender cup. The mixing process was done in the dry state and took place in small, short intervals so as not to heat up the toner and melt it. Melting the toner and binding it to the pigment was undesirable because then the solid mixing had to be crushed to powder again.
• the mixing process started with powder and ended with a powder mix.
• the fluorescent dye adhered to the toner particles by cohesive forces.
• the resulting toner was used to develop an image on a MIDAX 300 printer and transferred to OCR #24 paper.
• the samples were found to have the same image quality and optical density as standard MIDAX and when viewed under UV light exhibited a high degree of yellow-green fluorescence.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Developing Agents For Electrophotography (AREA)
• Printing Methods (AREA)

Applications Claiming Priority (2)

Publications (1)

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Cited By (5)

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Citations (6)

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• 1993
  • 1993-07-30 EP EP93306055A patent/EP0586093A1/fr not_active Withdrawn
  • 1993-08-02 NZ NZ24830893A patent/NZ248308A/en unknown
  • 1993-08-03 CA CA 2101807 patent/CA2101807A1/fr not_active Abandoned
  • 1993-08-03 AU AU44381/93A patent/AU665847B2/en not_active Ceased
  • 1993-08-04 JP JP5212172A patent/JPH0683101A/ja active Pending

Patent Citations (6)

Non-Patent Citations (2)

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