US4772528A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid electrostatic developers composed of blended resins
Assignee: EIDP Inc
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Filing: 1987-05-06
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Granted: 1988-09-20
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Expires: 2007-05-06
Abstract
Abstract A liquid electrostatic developer containing negatively chargeable resin particles with improved charging characteristics, said developer consisting essentially of (A) nonpolar liquid having a Kauri-butanol value of less than 30, present in a major amount; (B) resin particles of a blend of at least two polymers, at least one polymer containing at least one acidic constituent having a pKa of less than 4.5 measured at 25° C. in water, and the blend having an acid number of at least one due to said acidic constitutent; the resin particles having an average by area particle size of less than 10 μm, and (C) nonpolar liquid soluble ionic or zwitterionic charge director compound. A preferred polymer blend is composed of polystyrene and a sulfonated polymer, e.g., poly(2-acrylamido-2-methyl-1-propanesulfonic acid). The average resin particle size by area is less than 10 μm. Optionally a colorant and other additives or adjuvants are present. The liquid electrostatic developer is useful in copying making proofs including digital color proofs, lithographic printing plates, and resists.
Inventors
- 👤 James R. Larson
- 👤 Torence J. Trout
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:13
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/12; G03G9/13; G03G9/131; G03G9/135; G03G9/1355
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
110 words
A liquid electrostatic developer containing negatively chargeable resin particles with improved charging characteristics, said developer consisting essentially of (A) nonpolar liquid having a Kauri-butanol value of less than 30, present in a major amount; (B) resin particles of a blend of at least two polymers, at least one polymer containing at least one acidic constituent having a pKa of less than 4.5 measured at 25° C. in water, and the blend having an acid number of at least one due to said acidic constituent; the resin particles having an average by area particle size of less than 10 μm, and (C) nonpolar liquid soluble ionic or zwitterionic charge director compound.
Claim 2
Dependent Claim
110 words
A liquid electrostatic developer containing negatively chargeable resin particles with improved charging characteristics, said developer consisting essentially of (A) nonpolar liquid having a Kauri-butanol value of less than 30, present in a major amount; (B) resin particles of a blend of at least two polymers, at least one polymer containing at least one acidic constituent having a pKa of less than 4.5 measured at 25° C. in water, and the blend having an acid number of at least one due to said acidic constituent; the resin particles having an average by area particle size of less than 10 μm, and (C) nonpolar liquid soluble ionic or zwitterionic charge director compound.
Claim 3
Dependent Claim
24 words
A liquid electrostatic developer according to claim 1 wherein the resin particles are substantially insoluble in nonpolar liquid (A) at temperatures below 40° C.
Claim 4
Dependent Claim
21 words
A liquid electrostatic developer according to claim 2 wherein the pKa of at least one acidic constituent is less than 3.0.
Claim 5
Dependent Claim
16 words
A liquid electrostatic developer according to claim 1 wherein the first polymer is poly(2-acrylamido-2-methyl-1-propane sulfonic acid).
Claim 6
Dependent Claim
17 words
A liquid electrostatic developer according to claim 1 wherein the first polymer is poly(styrene/2-acrylamido-2-methyl-1-propane sulfonic acid) (95%/5%).
Claim 7
Dependent Claim
33 words
A liquid electrostatic developer according to claim 4 wherein said second polymer is a copolymer of ethylene (89% by weight)/methacrylic acid (11% by weight) having a melt index of 100 at 190° C.
Claim 8
Dependent Claim
33 words
A liquid electrostatic developer according to claim 5 wherein said second polymer is a copolymer of ethylene (89% by weight)/methacrylic acid (11% by weight) having a melt index of 100 at 190° C.
Claim 9
Dependent Claim
14 words
A liquid electrostatic developer according to claim 4 wherein said second polymer is polystyrene.
Claim 10
Dependent Claim
14 words
A liquid electrostatic developer according to claim 5 wherein said second polymer is polystyrene.
Claim 11
Dependent Claim
52 words
A liquid electrostatic developer according to claim 1 wherein component (A) is present in 85.0 to 99.9% by weight component (B) is present in 0.1 to 15.0% by weight, based on the total weight of the developer, and component (C) is present in an amount of 1 to 1000 mg/g developer solids.
Claim 12
Dependent Claim
25 words
A liquid electrostatic developer according to claim 1 containing up to about 60% by weight of a colorant based on the weight of developer solids.
Claim 13
Dependent Claim
25 words
A liquid electrostatic developer according to claim 10 containinq up to about 60% by weight of a colorant based on the weight of developer solids.
Claim 14
Dependent Claim
14 words
A liquid electrostatic developer according to claim 11 wherein the colorant is a pigment.
Claim 15
Dependent Claim
28 words
A liquid electrostatic developer according to claim 13 whereln the percent pigment in the resin is 0.1% to 30% by weight based on the weight of developer solids.
Claim 16
Dependent Claim
14 words
A liquid electrostatic developer according to claim 11 wherein the colorant is a dye.
Claim 17
Dependent Claim
23 words
A liquid electrostatic developer according to claim 1 wherein the particles have an average by area particle size of less than 5 μm.
Claim 18
Dependent Claim
15 words
A liquid electrostatic developer according to claim 1 wherein component (C) is Basic Barium petronate.
Claim 19
Dependent Claim
13 words
A liquid electrostatic developer according to claim 1 wherein component (C) is lecithin.
Claim 20
Dependent Claim
21 words
A liquid electrostatic developer according to claim 1 wherein the resin particles comprise particles having a plurality of fibers extending therefrom.
Claim 21
Dependent Claim
14 words
A liquid eIectrostatlo deveIoper according to claim 1 wherein the resin particles are nonfibrous.
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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) | 1991-09-20 | 1992-03-21 | 1992-09-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-20 | 1996-03-21 | 1996-09-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-20 | 2000-03-21 | 2000-09-20 | $7700.00 | Window Closed / Lapsed |