Pressure-fixable developing powder
AssigneeMinnesota Mining and Manufacturing Company
InventorsDoyle L. Strong, Curtis Dale Hargadine
Life of this patent
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Abstract
A dry, pressure-fixable, developing powder comprising a thermoplastic component having a low creep compliance and a non-volatile component having a high creep compliance, wherein the low creep compliance material is present in a greater amount by volume than the other component.
Claims7
Flowable, pressure-fixable, dry powder particles, the binder material of said particles having a conductivity of at most 10.sup.-.sup.12 mho/cm., said binder comprising (a) about 74 to 98 parts by volume of a thermoplastic component having a softening point of at least about 60.degree.C., a 10-second shear creep compliance in the range of about 1 .times. 10.sup.-.sup.12 cm.sup.2 /dyne to 1 .times. 10.sup.-.sup.10 cm.sup.2 /dyne, and a heat deflection temperature below about 300.degree.C., and (b) about 2 to 26 parts by volume of a non-volatile component having a principal glass transition temperature below about 0.degree. C. and a 10-second shear creep compliance greater than about 8 .times. 10.sup.-.sup.8 cm.sup.2 /dyne;
- wherein said powder exhibits a transfer density of less than about 0.15 and a paper abrasion density of less than about 0.15;
- wherein said non-volatile component is an elastomer selected from the group consisting of synthetic diene rubbers, acrylate rubbers, polyurethane elastomers, and rubbery block copolymers;
- and wherein said binder further comprises a tackifier for said elastomer.
A powder in accordance with claim 5 wherein said electrically conductive particles have a conductivity of at least 10.sup.-.sup.2 mho/cm and an average diameter below about 100 millimicrons;
- and wherein said dry powder particles exhibit:
- a. an electronic conductivity ranging monatonically without decreasing from between about 10.sup.-.sup.11 and 10.sup.-.sup.4 mho/cm in a 100 v./cm. DC electrical field to between about 10.sup.-.sup.8 and 10.sup.-.sup.3 mho/cm in a 10,000 v./cm. DC electrical field,
- b. a number average particles diameter below about 20 microns, and
- c. a volume ratio of said electrically conductive particles to total dry powders particle volume of between 0.01/100 and 4/100.
Dependencies are inferred from the claim text.