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US3640751A Expired / Lapsed US ⏱️ 0.0 years remaining

Method for liquid-developing an electrostatic image

Assignee: Ricoh Co Ltd
•
Filing: 1968-10-31
•
Granted: 1972-02-08
•
Expires: 1988-10-31
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Abstract

Abstract An electrophotographic liquid-developing method comprising controlling the polarity of the toner by varying the mixing proportion of the dispersion media and/or the temperature of the developer solution. An electrostatic charge-substrate having an electrostatically charged latent image is immersed in the developer solution to convert such latent image into a visible image. Said developer solution comprises a toner consisting of pigment particles and at least one resin selected from the group consisting of alkyd resin, phenol resin and vinyl resin, and a carrier liquid in which said toner is dispersed. The carrier liquid comprises a mixture of two dispersion media having different affinities to said resin. Dispersion media having a larger affinity to the resin include halogenated hydrocarbons, aromatic hydrocarbons and petroleum hydrocarbons containing aromatic ingredients. Dispersion media having a smaller affinity to the resin include isoparaffinic and paraffinic hydrocarbons.

Inventors

  • 👤 Kazuhiko Kasuya
  • 👤 Wasaburo Ohta
  • 👤 Zenjiro Okuno

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-24 14:34
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/12; G03G9/13; G03G9/132; G03G13/00; G03G13/06; G03G13/10; G03G9/125; G03G9/131; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2991; Y10T428/31504; Y10T428/31786

Claims Analysis

Total Claims: 13
Claim 1
Independent Claim 9 words
The method of claim 1 wherein (b) is CCl3F.
Claim 2
Dependent Claim 9 words
The method of claim 1 wherein (b) is perchloroethylene.
Claim 3
Dependent Claim 18 words
The method of claim 1 wherein (b) is petroleum hydrocarbOn containing about 99 volume percent of isoparaffinic hydrocarbon.
Claim 4
Dependent Claim 9 words
The method of claim 1 wherein (b) is ligroin.
Claim 5
Dependent Claim 18 words
The method of claim 1 wherein (b) is petroleum hydrocarbon containing about 98 volume percent of aromatic hydrocarbon.
Claim 6
Dependent Claim 24 words
The method of claim 1 wherein (b) is petroleum hydrocarbon containing about 25 percent of aromatic hydrocarbon and 70 volume percent of paraffinic hydrocarbon.
Claim 7
Dependent Claim 24 words
The method of claim 1 wherein (b) is petroleum hydrocarbon containing 15 volume percent of aromatic hydrocarbon and 80 volume percent of paraffinic hydrocarbon.
Claim 8
Dependent Claim 9 words
The method of claim 1 wherein (b) is toluene.
Claim 9
Dependent Claim 172 words
In a method for liquid developing an electrostatic latent image to form a visible image by immersion in a liquid developer comprising a dispersion of an electrically charged toner in a carrier liquid, said toner comprising fine particles of carbon black coated with phenol resin, said carrier liquid consisting essentially of a mixture of (a) a first dispersion medium of petroleum hydrocarbon containing about 98 volume percent of aromatic hydrocarbon and having a relatively large solubility to said resin, and (b) a second dispersion medium of petroleum hydrocarbon containing about 99 volume percent of isoparaffinic hydrocarbon and having a relatively small solubility to said resin, the improvement comprising adding to and mixing with said liquid developer having a first electrical polarity an additional quantity of one of said dispersion mediums (a) or (b) in an amount so that the resultant composition has a volume concentration of the (b) component within the range of opposite polarity, for the various weight ratios of phenol resin to carbon black, as defined by the following table:
Claim 10
Dependent Claim 16 words
The method of claim 10 wherein the weight ratio of resin to carbon black is 1/1.
Claim 11
Dependent Claim 16 words
The method of claim 10 wherein the weight ratio of resin to carbon black is 2/1.
Claim 12
Dependent Claim 16 words
The method of claim 10 wherein the weight ratio of resin to carbon black is 3/1.
Claim 13
Dependent Claim 16 words
The method of claim 10 wherein the weight ratio of resin to carbon black is 4/1.

References Cited (Backward Citations)

US3058914A Cited
US3251687A Cited
US3220830A Cited
US3296140A Cited
US3507679A Cited
US3356498A Cited
US3357828A Cited
US3438004A Cited
US3444083A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1975-02-07 1975-08-09 1976-02-08 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1979-02-07 1979-08-09 1980-02-08 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1983-02-07 1983-08-09 1984-02-08 $7700.00 Window Closed / Lapsed

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