WO1996001442A1 - Toner electrophotographique d'amplification de charge negative - Google Patents

Toner electrophotographique d'amplification de charge negative Download PDF

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Publication number
WO1996001442A1
WO1996001442A1 PCT/NL1994/000157 NL9400157W WO9601442A1 WO 1996001442 A1 WO1996001442 A1 WO 1996001442A1 NL 9400157 W NL9400157 W NL 9400157W WO 9601442 A1 WO9601442 A1 WO 9601442A1
Authority
WO
WIPO (PCT)
Prior art keywords
toner
liquid
negative
particles
compound
Prior art date
Application number
PCT/NL1994/000157
Other languages
English (en)
Inventor
Benzion Landa
Yaacov Almog
Original Assignee
Indigo N.V.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Indigo N.V. filed Critical Indigo N.V.
Priority to AU74685/94A priority Critical patent/AU7468594A/en
Priority to PCT/NL1994/000157 priority patent/WO1996001442A1/fr
Publication of WO1996001442A1 publication Critical patent/WO1996001442A1/fr

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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
    • G03G9/12—Developers with toner particles in liquid developer mixtures
    • 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
    • G03G9/12—Developers with toner particles in liquid developer mixtures
    • G03G9/135—Developers with toner particles in liquid developer mixtures characterised by stabiliser or charge-controlling agents

Definitions

  • Electrophotographic toner for negative charging FIELD AND BACKGROUND OF THE INVENTION This invention relates to the field of electrostatic imaging and, more particularly, to the preparation of liquid toners containing components for enhancing negative charging of liquid toner particles.
  • a latent electrostatic image is generally produced by first providing a photoconductive imaging surface with a uniform electrostatic charge, e.g. by exposing the imaging surface to a charge corona.
  • the uniform electrostatic charge is then selectively discharged by exposing it to a modulated beam of light corresponding, e.g., to an optical image of an original to be copied, thereby forming a latent electrostatic image having a background portion at one potential and a "print" portion at another potential.
  • the latent electrostatic image can then be developed by applying to it charged pigmented toner particles, which adhere to the "print" portions of the photoconductive surface to form a toner image which is subsequently transferred by various techniques to a substrate (e.g. paper). It will be understood that other methods may be employed to form an electrostatic image, such as, for example, providing a carrier with a dielectric surface and transferring a preformed electrostatic charge to the surface.
  • the charge may be formed from an array of styluses.
  • This invention will be described in respect of office copiers, though it is to be understood that it is applicable to other uses involving electrostatographics including electrostatographic printing.
  • the toner particles are usually dispersed in an insulating non-polar liquid carrier such as an aliphatic hydrocarbon fraction, which generally has a high-volume resistivity above 10 9 ohm cm, a dielectric constant below 3.0 and a low vapor pressure (less then 10 torr. at 25 °C).
  • the liquid developer system further comprises so-called charge directors, i.e.
  • Low background conductivity charge director as used herein is defined as a charge director which has a low specific low field conductivity, more specifically, ⁇ at 0.1% by weight of carrier liquid is less than 10 pmho/cm. Efficacy of the method is believed to result from the presence of halogenocarbon (and more preferably fluorocarbon) chains bonded to the toner material at the surface of the toner particles.
  • the present invention provides a composition suitable for use in the preparation of liquid toners of the negative type for electrostatic imaging, which comprises: an insulating non-polar carrier liquid; and toner particles micro-dispersed in said carrier liquid, which particles have been treated with at least one compound of formula R'SiC ⁇ , wherein R' is as defined above.
  • the invention provides a method for producing liquid toners for electrostatic imaging processes of the negative toner type, which method comprises the steps of: preparing a micro-dispersion of toner particles in an insulating non-polar carrier liquid; treating said micro-dispersed toner particles with at least one compound of formula R'SiCl 3 , wherein R' is as defined above; and adding to the thus-treated micro-dispersed toner particles, at least one low background conductivity negative charge director compound.
  • the invention provides an electrostatic imaging process of the negative toner type which comprises the steps of : forming a charged latent electrostatic image on a photoconductive surface ; applying to said surface the liquid toner according to the invention, or prepared according to a method of the invention ; and transferring the resulting toner image to a substrate .
  • the toner particles which in accordance with the present invention are treated with at least halogenocarbon compound , pre ferably a f luorocarbon compound such as R ' SiCl 3 , where R ' is a halogenocarbon radical , preferably a saturated fluorocarbon radical and preferably comprise at least one resin and at least one pigment .
  • At least one low background conductivity negative charge director compound may be present in the l iqui d developer , e . g . , at a concentration of from about 0. 1 to about 20% ( preferably from about 0.2 to about 10% ) , by weight , based on the weight o f the toner particles .
  • the carrier l iqui d may e . g . comprise at least one branched-chain aliphatic hydrocarbon, such as an isoparaf f inic fraction which has a boiling range above 155°C.
  • n is from 1 to 6, and in this embodiment R' may be e.g.
  • n is from 7 to 20, and in this embodiment R' may be e.g. 1H, 1H, 2H, 2H-perf luorooctyl .
  • R'SiCl3 are also referred to herein by the respective formulae CF3CH 2 CH 2 SiCl3 and C 8 F 13 H 4 SiCl3.
  • the toner particles including, in particular, resins and pigments), insulating non-polar carrier liquids, and low background conductivity negative charge director compounds, which may suitably be used in the liquid toners and the compositions of the invention may be those known in the art.
  • the insulating non-polar liquid carrier which should preferably also serve as carrier for the charge directors, is most suitably a hydrocarbon fraction, particularly an aliphatic hydrocarbon fraction, having suitable electrical and other physical properties.
  • the carrier is preferably an insulating non polar carrier liquid hydrocarbon having a volume resistivity above l ⁇ " ohm-cm and a dielectric constant below 3.0.
  • Preferred solvents are the series of branched-chain aliphatic hydrocarbons and mixtures thereof, e.g. the isoparaf f inic hydrocarbon fractions having a boiling range above about 155 ⁇ C, which are commercially available under the name Isopar (a trademark of the Exxon Corporation).
  • the toner particles may comprise, e.g., thermoplastic resin particles as is known in the art.
  • the pigments utilized in the present invention are also those which are essentially known in the art.
  • the at least one compound of formula R'SiCl is preferably used in an amount of more than about 2% by weight, more preferably within the range of about 3 to about 10% by weight, based on the weight of the toner solids. While the present invention is not to be regarded as limited by any theory of operation, it is presently believed that the compounds R'SiCl 3 may hydrolyze and/or self- condense to polysiloxanes which modify the toner particle surface by hydrogen bonding and/or reaction e.g.
  • the specific surface area of the toner particles is typically 1 m 2 /g and the MW of the compound R'SiC ⁇ where R' is (e.g.) 1H, 1H, 2H, 2H-perfluorooctyl, is 481, the amount of this compound required to cover the toner particle in a monolayer is about 70mg/g, or 7%, which is quite close to the empirically used amounts. It has been noted that in practice when using the compound R'SiCl3 where R' is (e.g. ) 3, 3, 3-trifluoropropyl, the toner dispersion should be rinsed several times (for example with Marcol 82 or Isopar), before adding negative charge director, in order to avoid high background conductivity.
  • the particles are di spersed in Marcol 82 which is therea f ter charged wi th Lubri zo l 890 negat ive charge director .
  • the toner used in the experiment whose results are shown in Table 1 , is produced by compounding 60g of Dynacol 7150 , a hydroxyl terminated copolyester ( Hulls ) together with 13.3 g of each of yellow pigment Sicomet D 1355DD, cyan pigment BT 583D and magenta pigment FR6B .
  • the compounding was carried out on a two roll mill, heated with oil at 140 C C at 60 rpm and at a torque of 40Nm for about 20 min. The material is discharged from the rollers and is shredded into small pieces.
  • the chargeability of the toner dispersion is indicated by the dif ference between the high field and low field conductivities , since the high f ield conductivity i s believed to include the contributions of the carrier liquid and the particles and the low field conductivity is believed to include almost only the effects of carrier liquid conductivity.
  • the onset of particle charging started at 2-3% and is not yet saturated even at 5-10%.
  • toner materials suitable for use in the invention are Elvax II type polymers, Hydroxy and Carboxy terminated resins, styrene-allyl alcohol polymers. Of these materials only the Elvax II materials can be charged sufficiently without the treatment described herein.
  • EXAMPLE 1 (a) 80 g of Acryloid B67, a resin marketed by Rohm and Haas, and 20 g of Mogul L carbon black, are loaded onto the rolls of a Brabender 2-roll mill, preheated by an oil heating unit to 140"C, operating at a speed of 60 rpm and a torque of 40 Nm.
  • EXAMPLE 2 20 9 of Acryloid B67, 60 g of Surlyn 9020 (Dupont) and 20 g of Mogul L carbon black, are loaded onto the rolls of a Brabender 2-roll mill, preheated by an oil heating unit to 140°C, operating at a speed of 60 rpm and a torque of 40 N.m. 100 g of Marcol 82 is added and after about 20 minutes the material is discharged and shredded into small pieces. (b) 60 g of the shredded material from (a), together with 140 g of Marcol 82, are ground in an SO attritor (Union Process) for 16.5 hours, while the attritor is cooled with tap water at 5°C.
  • SO attritor Union Process
  • the resultant particles have a median size of 1.36 micrometers.
  • (c) The product of (b) is diluted to 2% n.v.s with Marcol 82. 100 mg CgF ⁇ H ⁇ SiC ⁇ per g of imaging material are added to the dispersion and the system is left to equilibrate for 12 hours. Lubrizol 890 (100 mg/g imaging material) are added. The product has a high field conductivity of 19 pmho/cm, which represents good chargeability in Marcol 82.
  • EXAMPLE 3 (a) 74 parts by weight of Dynacol 7150, a resin marketed by Hulls, 25 parts by weight of BT583D blue pigment (Cookson), 18.5 parts by weight of Mogul L carbon black, and 5.2 parts by weight of Dertocal 140 calcium resinate (DRT, France) are loaded onto the rolls of a Brabender 2-roll mill preheated by an oil heating unit to 140°C, operating at a speed of 60 rpm and a torque of 40 N.m. After about 20 minutes the material is discharged and shredded into small pieces.
  • Dynacol 7150 a resin marketed by Hulls
  • BT583D blue pigment Cookson
  • Mogul L carbon black 18.5 parts by weight
  • DTT Dertocal 140 calcium resinate
  • (c) The product of (b) is diluted to 2% n.v.s with Marcol 82. 100 mg CgF ⁇ H ⁇ SiCl per g of imaging material are added to the dispersion and the system is left to equilibrate for 12 hours . Lubrizol 890 ( 100 mg/g imaging material ) charge director is added . The product has a high field conductivity of 34 pmho/cm , which represents good chargeability in Marcol 82.
  • EXAMPLE 4 (a) 70 g of Dynacol 7150 and 30g of FR6B magenta pigment (Toyo) are loaded onto the rolls of a Brabender 2- roll mill, preheated by an oil heating unit to 140°C, operating at a speed of 60 rpm and a torque of 40 N.m. After about 20 minutes the material is discharged and shredded into small pieces. (b) 50 g of the shredded material from (a), together with 150 g of Marcol 82, are ground in an SO attritor (Union Process) for 17 hours, while cooling the attritor with tap water at 5°C. The resultant particles have a median size of 2.25 micrometers.
  • SO attritor Union Process
  • (c) The product of (b) is diluted to 2% n.v.s with Marcol 82. 80 mg CF 3 CH2CH 2 SiCl3 per g of imaging material are added to the dispersion and the system is left to equilibrate for 12 hours. It is centrifuged at 5000 rpm for 10 minutes, after which the supernatant is removed and replaced by fresh Marcol 82. Lubrizol 890 (60 mg/g imaging material) is added. After 1 hour of equilibration the product has a particle conductivity of 25 pmho/cm, which represents good chargeability in Marcol 82.
  • EXAMPLE 5 (a) 750 g Dynacol 7150 and 30 g BT583D blue pigment (Cookson) are loaded onto the rolls of a Brabender 2-roll mill, preheated by an oil heating unit to 140°C, operating at a speed of 60 rpm and a torque of 40 N.m. After about 20 minutes the material is discharged and shredded into small pieces. (b) 50 g of the shredded material from (a), together with 150 g of Marcol 82, are ground in an SO attritor (Union Process) for 17 hours, while cooling the attritor with tap water at 5 ⁇ C. The resultant particles have a median size of 3.08 micrometer. (c) The product of (b) is diluted to 2% n.v.s with 1 Marcol 82 . 80 mg CF3CH 2 CH 2 SiCl3 per g of imaging material
  • Lubrizol 890 100 mg/g imaging
  • the resultant particles have a median size of

Abstract

Composition servant à préparer des toners liquides de type négatif, afin d'obtenir une image électrostatique et comprenant: un véhicule liquide isolant et non polaire; des particules de toner en micro-dispersion dans ledit véhicule liquide, lesdites particules ayant subi un traitement de surface, de telle façon que le matériau de toner à la surface desdites particules comporte des chaînes de carbone halogéné.
PCT/NL1994/000157 1994-07-06 1994-07-06 Toner electrophotographique d'amplification de charge negative WO1996001442A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
AU74685/94A AU7468594A (en) 1994-07-06 1994-07-06 Electrophotographic toner for negative charging
PCT/NL1994/000157 WO1996001442A1 (fr) 1994-07-06 1994-07-06 Toner electrophotographique d'amplification de charge negative

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/NL1994/000157 WO1996001442A1 (fr) 1994-07-06 1994-07-06 Toner electrophotographique d'amplification de charge negative

Publications (1)

Publication Number Publication Date
WO1996001442A1 true WO1996001442A1 (fr) 1996-01-18

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Country Status (2)

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AU (1) AU7468594A (fr)
WO (1) WO1996001442A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6212353B1 (en) 1996-12-03 2001-04-03 Indigo N.V. Method and apparatus for cleaning an image transfer member
US6562539B1 (en) 1999-07-05 2003-05-13 Indigo N.V. Printers and copiers with pre-transfer substrate heating
EP2691814A1 (fr) * 2011-03-30 2014-02-05 Hewlett-Packard Indigo B.V. Composition d'encre électrostatique

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1991002297A1 (fr) * 1989-07-31 1991-02-21 Spectrum Sciences B.V. Compositions directrices de charges ameliorees pour revelateurs liquides
JPH04145453A (ja) * 1990-10-05 1992-05-19 Toyo Ink Mfg Co Ltd 電子写真用液体現像剤
US5244766A (en) * 1991-12-03 1993-09-14 Xerox Corporation Halogenated resins for liquid developers

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1991002297A1 (fr) * 1989-07-31 1991-02-21 Spectrum Sciences B.V. Compositions directrices de charges ameliorees pour revelateurs liquides
JPH04145453A (ja) * 1990-10-05 1992-05-19 Toyo Ink Mfg Co Ltd 電子写真用液体現像剤
US5244766A (en) * 1991-12-03 1993-09-14 Xerox Corporation Halogenated resins for liquid developers

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
CHEMICAL ABSTRACTS, vol. 117, no. 24, 14 December 1992, Columbus, Ohio, US; abstract no. 242716q, page 613; column 2; *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6212353B1 (en) 1996-12-03 2001-04-03 Indigo N.V. Method and apparatus for cleaning an image transfer member
US6562539B1 (en) 1999-07-05 2003-05-13 Indigo N.V. Printers and copiers with pre-transfer substrate heating
EP2691814A1 (fr) * 2011-03-30 2014-02-05 Hewlett-Packard Indigo B.V. Composition d'encre électrostatique
EP2691814A4 (fr) * 2011-03-30 2014-10-29 Hewlett Packard Indigo Bv Composition d'encre électrostatique

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