US5387489A
Expired / Lapsed
US
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Processes for the preparation of developer compositions
Assignee: Xerox Corp
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Filing: 1993-07-28
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Granted: 1995-02-07
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Expires: 2013-07-28
Abstract
Abstract Disclosed is a process for preparing a liquid or dry electrophotographic developer comprising: (a) forming a melt mixture comprised of a polymer resin or resins, a colorant, a charge director, and a nonaqueous solvent to obtain a first suspension of colored polymeric particles with a volume average diameter of from about 5 to about 100 microns; and (b) homogenizing with a dairy piston homogenizer said first suspension under pressure of from about 100 to about 500 Bars to obtain a second suspension containing colored polymeric particles with a volume average diameter of from about 0.1 to about 5 microns.
Inventors
- 👤 Timothy J. Fuller
- 👤 James R. Larson
- 👤 Frank J. Bonsignore
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:44
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/0802; G03G9/0815; G03G9/0804; G03G9/12
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
97 words
A process for preparing a liquid or dry electrophotographic developer comprising: (a) forming a melt mixture comprised of a polymer resin or resins, a colorant, a charge director, and a nonaqueous solvent to obtain a first suspension of colored polymeric particles with a volume average diameter of from about 5 to about 100 microns; and (b) homogenizing with a dairy piston homogenizer said first suspension under pressure of from about 100 to about 500 Bars to obtain a second suspension containing colored polymeric particles with a volume average diameter of from about 0.1 to about 5 microns.
Claim 2
Dependent Claim
97 words
A process for preparing a liquid or dry electrophotographic developer comprising: (a) forming a melt mixture comprised of a polymer resin or resins, a colorant, a charge director, and a nonaqueous solvent to obtain a first suspension of colored polymeric particles with a volume average diameter of from about 5 to about 100 microns; and (b) homogenizing with a dairy piston homogenizer said first suspension under pressure of from about 100 to about 500 Bars to obtain a second suspension containing colored polymeric particles with a volume average diameter of from about 0.1 to about 5 microns.
Claim 3
Dependent Claim
62 words
A process in accordance with claim 1 wherein the polymer resin is selected from the group consisting of polymers and copolymers prepared from monomer selected from the group of unsaturated monomers consisting of styrene and derivatives thereof, monocarboxylic acids and derivatives thereof; dicarboxylic acids and derivatives thereof; vinyl ketones; vinyl ethers; vinyl naphthalene; mono-olefins; diolefins; vinylidene halides; N-vinyl compounds; and mixtures thereof.
Claim 4
Dependent Claim
33 words
A process in accordance with claim 1 wherein the colorant is selected from the group consisting of cyan, yellow, magenta, red, green, blue, brown, orange and black pigments or dyes, and mixtures thereof.
Claim 5
Dependent Claim
28 words
A process in accordance with claim 1 wherein said charge director is selected from the group consisting of a fatty acid or fatty acid salt and mixtures thereof.
Claim 6
Dependent Claim
35 words
A process in accordance with claim 1 wherein the nonaqueous solvent is selected from the group consisting of linear and branched aliphatic hydrocarbons with from about 10 to about 25 carbon atoms and mixtures thereof.
Claim 7
Dependent Claim
36 words
A process according to claim 1 further comprising dispersing said melt mixture with high shear or ball milling, and or heating with agitation from about 25° C. to about 100° C., to obtain said first suspension.
Claim 8
Dependent Claim
18 words
A process according to claim 6 further comprising cooling said first suspension after heating to about 25° C.
Claim 9
Dependent Claim
22 words
A process according to claim 1 further comprising isolating from said second suspension the pigmented polymeric particles and optionally washing and drying.
Claim 10
Dependent Claim
51 words
A process according to claim 1 further comprising thermally cycling or shocking said first suspension at 25° C. by heating to 100° C. over a period of about 1 to about 10 minutes and then rapidly cooling to about 10° C. to about 25° C. just prior to said homogenization step.
Claim 11
Dependent Claim
23 words
A process in accordance with claim 1 wherein the first suspension is homogenized under a pressure of about 200 to about 350 Bars.
Claim 12
Dependent Claim
28 words
A process in accordance with claim 1 wherein the colored polymeric particles obtained have an area average particle diameter of from about 1.0 micron to about 2.5 microns.
Claim 13
Dependent Claim
27 words
A process in accordance with claim 1 wherein the pigmented polymeric particles obtained have a geometric particle size distribution (GSD) of from about 1.2 to about 1.5.
Claim 14
Dependent Claim
39 words
A process in accordance with claim 1 wherein the polymer resin has a number (M n ) and weight (M w ) average molecular weight between about 5,000 to about 500,000 and about 10,000 to about 2,000,000, 2,000,000, respectively.
Claim 15
Dependent Claim
49 words
A process in accordance with claim 1 wherein the number (M n ) and weight average molecular weight (M w ) of the polymer resin is between about 5,000 to about 50,000 and about 10,000 to about 100,000, respectively, and a polydispersity of between about 1 and about 15.
Claim 16
Dependent Claim
44 words
A liquid developer obtained by the process of claim 1 comprising a polymer resin or resins, a colorant, a charge director, and a nonaqueous solvent wherein the resulting colored polymeric particles have a volume average diameter of from about 1 to about 4 micrometers.
Claim 17
Dependent Claim
70 words
A liquid developer according to claim 15 wherein the polymeric resin or resins comprises from about 70 to about 98 percent by weight of the solids content of the developer, the colorant comprises from about 1 to about 30 percent by weight of the solids content of the developer, and the charge director comprises from about 1 to about 15 percent by weight of the solids content of the developer.
Claim 18
Dependent Claim
26 words
A liquid developer according to claim 15 wherein the nonaqueous solvent is present from about 50 to about 98 of the total weight of the developer.
Claim 19
Dependent Claim
56 words
A liquid developer according to claim 15 further comprising adding surface additives, charge directors or flow aids comprised of fine powders of conductive metal oxides, metal salts, metal salts of fatty acids, colloidal silicas, titanates, quaternary ammonium salts, metal complexes, organometallic complexes, or mixtures thereof, to the surfaces of the suspended finely divided colored polymeric particles.
Claim 20
Dependent Claim
55 words
A liquid developer according to claim 18 wherein the charge directors are selected from the group consisting of a mixture of a colloidal silica or titanate, and an organoaluminum, organoboron, organozinc, organochromium complex of a salicylic acid or catechol and said charge directors are added to the bulk of the polymer in said melt mixture.
Claim 21
Dependent Claim
31 words
A liquid developer according to claim 19 further comprising adding said charge director additives to the continuous nonaqueous solvent phase for regulating the charging properties of the dispersed colored polymeric particles.
Claim 22
Dependent Claim
25 words
A liquid developer according to claim 20 wherein the charge director compounds are comprised of quarternary ammonium salts, conductive metal oxides, metal and organometallic salts.
Claim 23
Dependent Claim
26 words
A developer according to claim 21 further comprising removing the nonaqueous solvent to afford a dry free flowing powder suitable for use as a dry developer.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-02-06 | 1998-08-08 | 1999-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-02-06 | 2002-08-08 | 2003-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-02-06 | 2006-08-08 | 2007-02-07 | $7700.00 | Window Closed / Lapsed |