WO1994024606A1 - Revelateur electrophotographique liquide contenant un porteur liquide peu volatil - Google Patents

Revelateur electrophotographique liquide contenant un porteur liquide peu volatil Download PDF

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Publication number
WO1994024606A1
WO1994024606A1 PCT/US1994/003632 US9403632W WO9424606A1 WO 1994024606 A1 WO1994024606 A1 WO 1994024606A1 US 9403632 W US9403632 W US 9403632W WO 9424606 A1 WO9424606 A1 WO 9424606A1
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WO
WIPO (PCT)
Prior art keywords
developer composition
weight
liquid
copolymer
liquid developer
Prior art date
Application number
PCT/US1994/003632
Other languages
English (en)
Inventor
Joseph Degraft-Johnson
Feagin A. Wing, Jr.
Original Assignee
Olin Corporation
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 Olin Corporation filed Critical Olin Corporation
Priority to AU66241/94A priority Critical patent/AU6624194A/en
Publication of WO1994024606A1 publication Critical patent/WO1994024606A1/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
    • G03G9/13—Developers with toner particles in liquid developer mixtures characterised by polymer components
    • G03G9/131—Developers with toner particles in liquid developer mixtures characterised by polymer components obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • 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
    • G03G9/125—Developers with toner particles in liquid developer mixtures characterised by the liquid
    • 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
    • G03G9/1355—Ionic, organic compounds

Definitions

  • the present invention relates generally to liquid electrophotographic developers containing specific low volatile liquid carriers.
  • the present invention relates to nonaqueous dyed latex liquid developers that contain selected low volatile carrier liquids which have a very low vapor pressure and high flash point, as well as a viscosity low enough to allow adequate image development.
  • Liquid electrophotographic (also known as electrostatographic) developer compositions are used in office copy machines, computer print-out devices, lithographic master preparation and the like to create a visible counterpart from a latent electrostatic image.
  • Liquid toners generally consist of five components: a carrier liquid, coloring agent, fixative agent, dispersing agent, and charge director. In any given developer composition, there may be one or more of each of these components. Also, one or more chemicals in such developer compositions may simultaneously have multiple functions. For example, a dispersing agent may also act as a fixative. Moreover, when a polymeric dispersing agent is employed, the combination of coloring agent, fixing agent, and dispersing agent is sometimes called a dyed latex toner polymer.
  • the solid toner particles (including dyes or pigments) in the developer composition either migrate to the charged areas or the uncharged areas but not to both. If the toner particles go to the charged areas, this is called positive development. If the toner particles go to the uncharged areas, this is called reversal development.
  • the coloring agent should be essentially insoluble in the carrier liquid and preferably contain no contaminants which are soluble therein. Dyes are selected for their solubility in the fixing agent and insolubility in the carrier liquid as well as for their color. Moreover, pigments are chosen on the basis of proper color, the best intrinsic surface or migration properties, ease of grinding to a desired fine particle size, and the differential between its specific gravity and that of the carrier liquid.
  • Dyes are usually employed for coloring latex toner.
  • the resultant mixture is commonly called "a dyed latex”.
  • Dyes are incorporated therein by reacting them or by dissolving them into the latex polymer.
  • the fixative agent aids in the making of the toned or visual image a permanent part of the underlying substrate (e.g., paper).
  • the fixative agent portion is generally a synthetic polymer or copolymer which has the desirable characteristics of chemical stability, an unobjectionable color, and is insoluble in the liquid carrier as well as being compatible with the substrate onto which the image is deposited.
  • the last component of a dyed latex liquid developer is the charge director.
  • the charge director must be soluble or dispersible in the liquid carrier and must create or augment an electrostatic charge on micron or sub-micron toner particles.
  • the patent literature is replete with different charge director compositions. Typical charge directors are metal salts of long chain fatty acids, both substituted and unsubstituted.
  • volume resistance greater than 10 9 ohm-cm
  • dielectric constant of 3 or less
  • viscosity low enough to permit rapid migrations of particles which are attracted to the electrostatically charged image to be developed e.g., between about 0.5 and 2.5 centipose at room temperature
  • liquid electrostatographic toners (20) solubility parameter of net more than 8.5.
  • suitable carrier liquids for liquid electrostatographic toners including the following:
  • SHELLSOL T Shell Oil
  • SHELLZOLE 71 Shell Oil
  • the most currently used carrier liquids for electrophotographic liquid developers are made with aliphatic hydrocarbons having a flash point from about 100°F to 130°F and viscosities lower than 3.0 centiposes at 25°C.
  • ISOPAR G and H are examples of such commonly employed carrier liquids.
  • carrier liquids Amounts of liquid carrier vapor may be emitted by the electrophotographic platemaker during idle periods.
  • these types of carrier liquids have been recently classified by the United States Department of Transportation as being flammable, whereas they classified as only as combustible. This reclassification restricts their use.
  • plate and background densities vary undesirably during the life of the toner bath.
  • the present invention is directed to a dyed latex liquid developer composition which comprises:
  • the carrier liquid used in the present invention is preferably an aliphatic hydrocarbon carrier liquid having a conductivity of 10 "9 SIEMENS/cm or less, a dielectric constant of 3 or less, a flash point of about 80-115°C, and a viscosity of about 2.5-4.5 cps at 25°C and a vapor pressure of less than about 0.05 torr at 20°C.
  • the preferred carrier liquid is PD-23 Odorless Petroleum Hydrocarbon available from Witco Corporation. It is a clear, colorless, saturated aliphatic petroleum distillate. This product meets the Odorless Light Petroleum Hydrocarbon requirements of FDA 21 CFR 172.884.
  • the typical average molecular weight (ASTM D2502) of PD-23 is 220.
  • the kinematic viscosity value of PD-23 at 25°C is 3.60 cSt (equivalent to 2.87 centiposes at 25°C) .
  • Other typical properties of PD-23 are as follows:
  • the essential characteristics of all suitable carrier liquids of this invention are the high above-discussed electrical volume resistivity, the dielectric constant, flash point, viscosity, and vapor pressure.
  • a feature of these carrier liquids is a low Kauri-Butanol value, less than 30, preferably in the vicinity of 24 to 27, determined by ASTM D 1133.
  • the carrier liquid when ready for use, generally is about 80% to about 99% by weight of the dyed latex developer formulation. More preferably, the ready-to-use carrier liquid constitutes about 85% to about 98% by weight of the dyed latex developer formulation. Most preferably, the ready-to-use carrier liquid constitutes about 90% to 96% by weight. Of course, developer concentrates contain less carrier liquid (i.e., at least 70% by weight carrier liquid) .
  • the present invention contemplates both ready-to-use and concentrated forms.
  • the dyed latex of the present invention is a colloidal suspension of a synthetic resin in the carrier liquid.
  • the present invention encompasses any and all dye latexes used in the liquid developer art including the dyed latexes first disclosed in the above-noted Kosel patents, as well as in U.S. Patent No. 4,476,210, which issued to Croucher et al. on October 9, 1984.
  • the dyed latex of the present invention is the dispersed phase (i.e., dyed sterically stabilized thermoplastic resin particles) in the carrier liquid.
  • Such dyed latex particles of the present invention incorporate a dispersing agent, a fixative agent, and a colorant agent.
  • the dispersing agent portion of the dyed latex is preferably an amphipathic block or graft copolymer steric stabilizer which is prepared in an aliphatic dispersion medium (i.e, preferably, the carrier liquid) in the presence of a free radical initiator.
  • the preferred ingredients for this amphipathic steric stabilizer is lauryl methacrylate and glycidyl methacrylate is in the mole percent ratio range of about 98:2 to 90:10, more preferably, about 95:5.
  • This copolymer is preferably a random copolymer made by vinyl addition polymerization in the carrier liquid. This reaction is initiated by any free radical initiator.
  • a preferred example of such an initiator is VAZO-67, 2,2'-azo-bis- (2-methylbutyronitrile) supplied by DuPont.
  • This vinyl addition polymerization is preferably run at about 80°C to about 105°C, more preferably about 90-100°C.
  • the dispersing agent is made by reacting that copolymer with methacrylic acid.
  • the methacrylic acid groups react with oxirane groups on the glycidyl methacrylate moieties in the copolymer.
  • the resulting soluble copolymer contains pendent vinyl groups.
  • This esterification reaction is generally carried out in the presence of the dispersing medium (e.g., the liquid carrier) and the presence of an effective catalytic amount of a catalystic agent.
  • a catalystic agent e.g., dodecyldimethylamine.
  • This esterification reaction is preferably carried out from about 90°C to about 135°C, more preferably, from 110-130°C.
  • the preferred fixative agent portion of the dyed latex of the present invention is a thermoplastic resin which is insoluble in the carrier liquid.
  • One preferred fixative agent is a copolymer of n-butyl acid maleate with vinyl acetate, preferably in about a 5:95 to 15:85 weight percent ratio.
  • the above fixative agent copolymer is formed simultaneously with an attachment reaction of the fixative agent to the dispersing agent. This is accomplished by carrying out the copolymerization in the presence of the dispersing agent, the dispersing medium (e.g., carrier liquid), and a free radical initiator. The reaction is preferably carried out at a temperature of about 50°C to about 80°C, more preferably from about 60°C to about 70°C.
  • the resulting nonaqueous dispersion has a portion which is soluble in the carrier liquid (e.g., the dispersion agent portion) and a portion which is not soluble (i.e., the fixative portion).
  • the dispersing agent portion (amphipathic stabilizer) becomes intimately bound to the fixative agent (a synthetic resin particle) .
  • intimately bound we intend to define those chemical, as well as physical, interactions that irreversibly anchor the amphipathic stabilizer in such a way that it cannot leave the particle under normal operating conditions.
  • the colorant agent portion of the dyed latex of the present invention may be any suitable dye or combination of dyes useful in making these types of liquid developer formulations.
  • the colorant agent and the nonaqueous dispersion produced above are mixed and heated together to a temperature of about 60-80°C until the dye is sufficiently reacted with, assimilated, bound up or absorbed into the fixative agent portion (or resin particles) .
  • the dye is preferably previously ground to very small particles before this mixing step.
  • the dyes used herein are essentially insoluble in the carrier liquid.
  • the resulting dyed latex dispersion preferably contains about 20-30% by weight solids and may be used as is in the developer composition of the present invention.
  • the dyed latex solids generally constitute about 0.5% to 5% by weight of total developer composition.
  • the dyed latex solids constitute about 0.8% to 3% by weight, most preferably, about 1% to 1.5% by weight of total developer composition.
  • Any charge director used in latex-type developer compositions may be employed in the present invention.
  • ASA-3 anti-static additive for liquid hydrocarbons. This additive is believed to be comprised of 1-10 parts each of: 1. a chromium salt of a C l _ alkyl salicylic acid;
  • a second known charge director composition is described in U.S. Patent No. 4,869,991, which issued to Joseph deGraft-Johnson, Chi Ma, and Richard R.L. Wells on September 26, 1989. That charge director composition is dispersed in a solvent and comprises: A. Salt mixture comprised of 1-10 parts by weight each of:
  • a chromium salt of a C ⁇ g alkyl salicylic acid (i) a calcium didecyl sulfosuccinate; and (iii) a salt of the didecyl ester of sulfosuccinic acid and at least 50% of the basic nitrogen radicals of a copolymer of lauryl methacrylate, stearylmethacrylate, and 2-methyl-5-vinyl pyridine, said copolymer having a vinyl pyridine content of 20-30% by weight and an average molecular weight of 15,000- 250,000; and B.
  • the charge director (as solution) generally constitutes about 0.5% to about 6% by weight of total liquid developer composition.
  • the charge director solution constitutes about 1% to 5% of total liquid developer composition.
  • the charge director solids generally constitute about 0.01% to 0.25% by weight of the total developer.
  • a mineral oil additive it may be preferred to add a mineral oil additive.
  • the mineral oil component of the liquid developer composition of the present invention is preferably any mineral oil (CAS No. 8020-83-5) of sufficient purity so that any contaminants therein will not interfere with the desired end use.
  • Mineral oils generally consist of completely saturated aliphatic and alicyclic hydrocarbons. They are characterized by chemical and biological inertness, nonpolar structure, hydrophobic nature, and excellent electrical properties.
  • One preferred mineral oil is KLEAROL made by Witco. This mineral oil has a viscosity of 7-10 cSt at 40°C; 50-60 SUS at 110°F; and a flash point of 138°C.
  • the mineral oil preferably constitutes about 0.5% to 20% by weight of the liquid developer composition. More preferably, the mineral oil constitutes about 1% to about 10% by weight. Most preferably, the amount of mineral oil is about 2% to 5% by weight of the developer composition.
  • the present developer composition may contain additional optional ingredients as commonly used in the liquid electrophotographic developer art.
  • the present developer composition may be combined with other types of toner particles (e.g., attrited toners) to form hybrid liquid developers such as described in the above-noted Kosel patents.
  • hybrid-type developers will have improved cleanability properties.
  • developer ingredients may be combined according to any conventional blending method.
  • the preferred blending method involves adding a dispersion of the dyed latex into the carrier liquid followed by adding the charge director and then the mineral oil.
  • the ingredients are preferably thoroughly blended in a tank equipped with agitation means.
  • the following Examples and Comparative Examples further illustrate the present invention. All parts and percentages are by weight and all temperatures are Celsius unless explicitly stated otherwise.
  • the latex polymer was a graft-dispersion type polymer made in an aliphatic hydrocarbon solvent (ISOPAR G) . It was made in three separate steps as follows:
  • (l)n-Butyl Acid Maleate was made by heating maleic anhydride in n-butanol, as follows: Charge a 250 ml round-bottom flask fitted with reflux condenser, mechanical stirrer, and thermometer with:
  • ISOPAR H in a 400 beaker fitted with a thermometer and magnetic stirrer. The mixture was heated to 70°C + 2°C and held for 30 minutes, and the resulting dyed latex was cooled to room temperature.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Liquid Developers In Electrophotography (AREA)

Abstract

Une composition de développeur liquide de latex tinté se caractérise par: (a) un liquide porteur; (b) un latex teinté; et (c) un dispositif de guidage de charge. Ce liquide porteur possède une conductivité inférieure à environ 10-9 SIEMENS/cm; une constante diélectrique inférieure à environ 3; un point d'éclair d'environ 80 °C à environ 115 °C; une viscosité d'environ 2,5 à environ 4,5 centipoises à 25 °C; et une pression de vapeur inférieure à environ 0,05 torr à 20 °C.
PCT/US1994/003632 1993-04-19 1994-04-01 Revelateur electrophotographique liquide contenant un porteur liquide peu volatil WO1994024606A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU66241/94A AU6624194A (en) 1993-04-19 1994-04-01 Liquid electrophotographic developer with low volatile carrier liquid

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US4844793A 1993-04-19 1993-04-19
US048,447 1993-04-19

Publications (1)

Publication Number Publication Date
WO1994024606A1 true WO1994024606A1 (fr) 1994-10-27

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Application Number Title Priority Date Filing Date
PCT/US1994/003632 WO1994024606A1 (fr) 1993-04-19 1994-04-01 Revelateur electrophotographique liquide contenant un porteur liquide peu volatil

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AU (1) AU6624194A (fr)
WO (1) WO1994024606A1 (fr)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3990980A (en) * 1974-01-14 1976-11-09 Philip A. Hunt Chemical Corporation Hybrid liquid toners
US4869991A (en) * 1988-03-24 1989-09-26 Olin Hunt Specialty Products Inc. Charge director composition for liquid toner formulations

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3990980A (en) * 1974-01-14 1976-11-09 Philip A. Hunt Chemical Corporation Hybrid liquid toners
US4869991A (en) * 1988-03-24 1989-09-26 Olin Hunt Specialty Products Inc. Charge director composition for liquid toner formulations

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AU6624194A (en) 1994-11-08

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