EP0898206A2 - A method for coating carrier particles for use in electrostatic developers - Google Patents
A method for coating carrier particles for use in electrostatic developers Download PDFInfo
- Publication number
- EP0898206A2 EP0898206A2 EP98202689A EP98202689A EP0898206A2 EP 0898206 A2 EP0898206 A2 EP 0898206A2 EP 98202689 A EP98202689 A EP 98202689A EP 98202689 A EP98202689 A EP 98202689A EP 0898206 A2 EP0898206 A2 EP 0898206A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- carrier particles
- particles
- vessel
- coating
- solvent
- Prior art date
- Legal status (The legal status 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 status listed.)
- Granted
Links
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
- G03G9/10—Developers with toner particles characterised by carrier particles
- G03G9/113—Developers with toner particles characterised by carrier particles having coatings applied thereto
- G03G9/1131—Coating methods; Structure of coatings
-
- 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
- G03G9/10—Developers with toner particles characterised by carrier particles
- G03G9/113—Developers with toner particles characterised by carrier particles having coatings applied thereto
- G03G9/1132—Macromolecular components of coatings
- G03G9/1135—Macromolecular components of coatings obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
- G03G9/1136—Macromolecular components of coatings obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds containing silicon atoms
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Developing Agents For Electrophotography (AREA)
Abstract
- bringing the carrier particles to be coated in a vessel equipped with means for agitating the carrier particles, so that the carrier particles occupy less than 85 % by volume of the vessel, and the agitation of the carrier particles is described by a Froude number between 0.2 and 20,
- adding a solution containing between 6 and 60 % by weight with respect to the total volume of the solution of chemical compounds for coating the carrier particles in a solvent with a boiling point of A °C to the vessel at such a rate that, at any time, the solvent is present in an amount lower than 1.25 10-4 ml per cm2 of surface of the carrier particles to be coated ,
- keeping the carrier particles in the vessel at a temperature of at most (A + 10) °C, and
- continuously evacuating the solvent.
Description
- bringing said carrier particles to be coated in a vessel equipped with means for agitating said carrier particles , so that said carrier particles occupy less than 85 % by volume of said vessel, and the agitation of the carrier particles is described by a Froude number between 0.2 and 20,
- adding a solution containing between 6 and 60 % by weight with respect to the total volume of said solution of chemical compounds for coating said carrier particles in a solvent with a boiling point of A °C to said vessel at such a rate that, at any time, said solvent is present in an amount lower than 1.25 10-4 ml per cm2 of surface of said carrier particles to be coated ,
- keeping said carrier particles in said vessel at a temperature of at most (A + 10) °C, and
- continuously evacuating said solvent.
The Froude number is a description of a specific ratio of inertia versus gravity forces, both forces being of importance in the description of agitation, as is discussed in the publication entitled KENZAHLEN UND ÄHNLICHKEITSGESETZE IM INGENIEURWESEN, by J. Stichlmair, p 33, published by Altos-Verlag Doris Stichlmair Essen 1990. The Froude number can be calculated as a dimensionless number using the formula:
In the method of the invention, the temperature of the loose bed of particles (i.e. the temperature of the particles in the vessel) is held at a temperature that is at most 10 °C higher than the boiling point of the solvent that is used in the solution containing the coating compound. Thus when the boiling point of the solvent is A °C, then the temperature of the loose bed (i.e. the particles in the vessel) is kept at a temperature that is at most (A + 10) °C, preferably the temperature in the vessel is at most (A + 5) °C. When a mixture of solvents is used, the temperature of the loose bed of particles is held at a temperature that is at most 10 °C higher, preferably at most 5 °C higher, than the boiling point of the solvent with the lowest boiling point. In this invention the boiling point means the boiling point at the atmospheric pressure at which the coating is carried out. When the method of this invention is carried out at normal atmospheric pressure-, the boiling point to be considered is the boiling point at normal atmospheric pressure, when the coating proceeds at lowered pressure, then the boiling point to be considered is the boiling point at that lowered pressure.
Claims (9)
- A method for coating carrier particles, having a volume average diameter between 20 and 200 µm, for use in electrostatic developers, comprising the steps of :bringing said carrier particles to be coated in a vessel equipped with means for agitating said carrier particles , so that said carrier particles occupy less than 85 % by volume of said vessel, and the agitation of the carrier particles is described by a Froude number between 0.2 and 20,adding a solution containing between 6 and 60 % by weight with respect to the total volume of said solution of chemical compounds for coating said carrier particles in a solvent with a boiling point of A °C to said vessel at such a rate that, at any time, said solvent is present in an amount lower than 1.25 10-4 ml per cm2 of surface of said carrier particles to be coated ,keeping said carrier particles in said vessel at a temperature of at most (A + 10) °C, andcontinuously evacuating said solvent.
- A method according to claim 1, wherein said Froude number is between 0.5 and 8 both limits included.
- A Method according to claim 1 or 2, wherein said solution contains between 15 and 40 % by weight with respect to the total volume of said solution of chemical compounds for coating said particles.
- A method according to any of claims 1 to 3, wherein said solution is added to said vessel at a rate that, at any time, said solvent is present in an amount lower than 0.6 10-4 ml per cm2 of surface of said particles to be coated.
- A method according to any of claims 1 to 4, wherein said carrier particles have an average weight Wavg such that 1. 10-11 Kg ≤ Wavg ≤ 5 10-8 Kg.
- A method according to any of claims 1 to 4, wherein said carrier particles have an average weight Wavg such that 1 10-10 Kg ≤ Wavg ≤ 1 10-8 Kg.
- A method according to any of claims 1 to 6, wherein said vessel with a mechanical mixer is a ploughshare mixer.
- A method according to any of claims 1 to 7, wherein said chemical compounds are selected from the group consisting of (a monomeric, polyfunctional organosilane, an hydrolysis product of a monomeric, polyfunctional organosilane, a reaction product of a monomeric, polyfunctional organosilane and a organosilane containing an heteroatom and a reaction product of a monomeric, polyfunctional organosilane and an alkoxide.
- A method according to any of the preceding claims wherein said carrier particles comprise magnetic material.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP19980202689 EP0898206B1 (en) | 1997-08-20 | 1998-08-08 | A method for coating carrier particles for use in electrostatic developers |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP97202551 | 1997-08-20 | ||
EP97202551 | 1997-08-20 | ||
EP19980202689 EP0898206B1 (en) | 1997-08-20 | 1998-08-08 | A method for coating carrier particles for use in electrostatic developers |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0898206A2 true EP0898206A2 (en) | 1999-02-24 |
EP0898206A3 EP0898206A3 (en) | 1999-03-17 |
EP0898206B1 EP0898206B1 (en) | 2003-02-19 |
Family
ID=26146795
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19980202689 Expired - Lifetime EP0898206B1 (en) | 1997-08-20 | 1998-08-08 | A method for coating carrier particles for use in electrostatic developers |
Country Status (1)
Country | Link |
---|---|
EP (1) | EP0898206B1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1146398A2 (en) * | 2000-04-11 | 2001-10-17 | Xeikon Nv | Method for coating carrier particles |
US6420029B1 (en) | 1998-11-26 | 2002-07-16 | Xeikon International | Hybrid carrier coating containing a silane network and a polymeric compound not containing silicon atoms |
US6551754B2 (en) | 2000-04-11 | 2003-04-22 | Xeikon, N.V. | Method for coating carrier particles |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3507686A (en) * | 1967-06-23 | 1970-04-21 | Xerox Corp | Method of coating carrier beads |
US3947271A (en) * | 1972-02-14 | 1976-03-30 | International Business Machines Corporation | Electrostatic imaging method using a polytetrafluoroethylene coated carrier particle |
GB2014876A (en) * | 1978-01-26 | 1979-09-05 | Xerox Corp | Coated carrier particles |
US5102769A (en) * | 1991-02-04 | 1992-04-07 | Xerox Corporation | Solution coated carrier particles |
US5340677A (en) * | 1991-04-26 | 1994-08-23 | Canon Kabushiki Kaisha | Carrier for electrophotography, two-component type developer for electrostatic images, process for producing carrier for electrophotography, and image forming method |
-
1998
- 1998-08-08 EP EP19980202689 patent/EP0898206B1/en not_active Expired - Lifetime
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3507686A (en) * | 1967-06-23 | 1970-04-21 | Xerox Corp | Method of coating carrier beads |
US3947271A (en) * | 1972-02-14 | 1976-03-30 | International Business Machines Corporation | Electrostatic imaging method using a polytetrafluoroethylene coated carrier particle |
GB2014876A (en) * | 1978-01-26 | 1979-09-05 | Xerox Corp | Coated carrier particles |
US5102769A (en) * | 1991-02-04 | 1992-04-07 | Xerox Corporation | Solution coated carrier particles |
US5340677A (en) * | 1991-04-26 | 1994-08-23 | Canon Kabushiki Kaisha | Carrier for electrophotography, two-component type developer for electrostatic images, process for producing carrier for electrophotography, and image forming method |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6420029B1 (en) | 1998-11-26 | 2002-07-16 | Xeikon International | Hybrid carrier coating containing a silane network and a polymeric compound not containing silicon atoms |
EP1146398A2 (en) * | 2000-04-11 | 2001-10-17 | Xeikon Nv | Method for coating carrier particles |
EP1146398A3 (en) * | 2000-04-11 | 2003-04-09 | Xeikon Nv | Method for coating carrier particles |
US6551754B2 (en) | 2000-04-11 | 2003-04-22 | Xeikon, N.V. | Method for coating carrier particles |
Also Published As
Publication number | Publication date |
---|---|
EP0898206A3 (en) | 1999-03-17 |
EP0898206B1 (en) | 2003-02-19 |
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