EP0437073A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Toner developed electrostatic imaging process for outdoor signs
Assignee: 3M Co
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Filing: 1990-12-20
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Granted: —
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Expires: 2010-12-20
Abstract
Abstract An electrographic imaging process is described in which electrostatic images are toned in sequence to form a multicolor intermediate image on a temporary dielectric receptor. The intermediate image is then transferred to a permanent receptor. Certain relative properties of the toner and the intermediate image, such as surface energy, Tg, work of adhesion, and complex dynamic viscosity, have been found to be important to the production of good final images. <IMAGE>
Inventors
- 👤 Hsin-Hsin C/O Minnesota Mining And Chou
- 👤 John F. C/O Minnesota Mining And Eisele
- 👤 Gaye K. C/O Minnesota Mining And Lehman
- 👤 Wu-Shyong C/O Minnesota Mining And Li
- 👤 Valdis C/O Minnesota Mining And Mikelsons
- 👤 Michael J. C/O Minnesota Mining And Petrich
- 👤 Prabhakara S. C/O Minnesota Mining And Rao
- 👤 Thomas J. C/O Minnesota Mining And Staiger
- 👤 Paul J. C/O Minnesota Mining And Wang
- 👤 Gregory L. C/O Minnesota Mining And Zwadlo
- 👤 Michael G. C/O Minnesota Mining And Baier
- 👤 Richard H. C/O Minnesota Mining And Olson
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 15:53
CPC Classifications
G; G03; G03G; G03G13/00; G03G5/00; G03G5/14; G03G5/147; G03G5/14708; G03G5/14713; G03G5/14747; G03G5/14769; G03G13/01; G03G5/02; G03G5/0202; G03G5/14717; G03G5/14734; G03G5/1476; G03G5/14773; G03G5/14791; G03G7/00; G03G7/0006
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
305 words
An electrographic process for producing multicolored toned images in an electrostatic printer, comprising the steps of a) providing a flexible imaging sheet having at least one surface exhibiting dielectric properties and toner release properties characterized by a surface energy between 14 ergs/cm² and 20 ergs/cm², said surface energy comprising not more than 5% polar component, b) moving said imaging sheet at a substantially steady rate through the printer, c) producing on said surface of said imaging sheet a first electrostatic latent image corresponding to a first color by imagewise deposition of charges, d) developing said first latent image by means of a rotating applicator bar with a first toner corresponding to said first color to produce a first toned image, said first toned image then exhibiting a scratch test strength of not less than 40 g and a surface energy of not more than 50 ergs/cm², e) drying said first toned image, f) repeating steps c), d), and e) in sequence using toners corresponding to at least one more color to complete said multicolored toned image,so that where a later developed toner overlays an earlier developed toner the interface created between said earlier toner and said later toner has a work of adhesion value greater than the largest of work of adhesion values of interfaces created between said toners and said imaging sheet surface, and g) bringing said multicolor toned image deposited on said surface of said imaging sheet in contact with a receptor sheet surface under pressure and at an elevated temperature, so that said multitoned image is transferred to said receptor sheet surface without distortion, said receptor sheet surface having a surface energy greater than the surface energy of said imaging sheet surface, and said receptor sheet surface having a T g value between 10°C and a value 5°C below said elevated temperature.
Claim 2
Dependent Claim
38 words
An electrographic process as recited in claim 1 wherein said flexible imaging sheet comprises a conducting substrate coated on one of its two major surfaces with a dielectric layer and a separate top layer having said release properties.
Claim 3
Dependent Claim
41 words
An electrographic process as recited in claim 2 wherein said top layer comprises a release material selected from the group consisting of silicone-urea block polymers containing from 1% to 65% by weight of polydimethylsiloxane, urethane-silicone copolymers, epoxy-silicone copolymers, and acrylic-silicone copolymers.
Claim 4
Dependent Claim
36 words
An electrographic process as recited in claims 1, 2 or 3 wherein said flexible imaging sheet comprises a conducting substrate coated on one of its two major surfaces with a dielectric layer having said release properties.
Claim 5
Dependent Claim
44 words
An electrographic process as recited in claim 4 wherein said dielectric layer comprises materials selected from the group consisting of terpolymers of polydimethylsiloxane, methylmethacrylate, and polystyrene, and copolymers of polydimethylsiloxane and methylmethacrylate, wherein the polydimethylsiloxane constitutes between 10% and 30% of total polymer weight.
Claim 6
Dependent Claim
25 words
An electrographic process as recited in claim 1 wherein said toners comprise a cyan toner, a magenta toner, a yellow toner, and a black toner.
Claim 7
Dependent Claim
53 words
An electrogaphic process as recited in claim 1 wherein said receptor sheet comprises a substrate carrying a thermoplastic layer comprising a polymer selected from the group consisting of a thermoplastic polymers with a complex dynamic viscosity value of less than about 2.5 x 10⁵ poise at a temperature equal to said elevated temperature.
Claim 8
Dependent Claim
39 words
An electrographic process as recited in claim 7 wherein said thermoplastic layer comprises polymers chosen from the group consisting of methylacrylates, butylmethacrylates, methylmethacrylate copolymers with other acrylates, ethylmethacrylates, isobutylmethacrylates, vinylacetate/vinylchloride copolymers of low molecular weight, polyurethane, and aliphatic polyesters.
Claim 9
Dependent Claim
41 words
An electrographic process as recited in claims 1, 5 or 7 wherein said substrate comprises a polymer selected from the group consisting of polyvinylchloride, acrylics, polyurethanes, polyethylene/acrylic acid copolymers, and polyvinyl butyrals, and said elevated temperature is between 50°C and 150°C.
Claim 10
Dependent Claim
23 words
The electrographic process of claims 1, 2 or 8 wherein said multicolored toned image is produced in one pass through said electrostatic printer.
Claim 11
Dependent Claim
74 words
An electrographic process as recited in claim 4 wherein said dielectric layer comprises a mixture of components A and B, said component A consisting of one or more members selected from the group consisting of dielectric polymers and resins, and said component B consisting of one or more members selected from the group consisting of release materials, the components A and B being present in a weight ratio in the range 1:10 to 10:1.
References Cited (Backward Citations)
No citation records indexed.
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