Electrophotographic coated carrier particles and methods thereof

Claim 2

A process for the preparation of carrier particles with substantially stable conductivity parameters which comprises (1) mixing carrier cores with a polymer mixture comprising from about 10 to about 90 percent by weight of a first polymer, and from about 90 to about 10 percent by weight of a second polymer, wherein said first and second polymers are not in close proximity in the triboelectric series; (2) dry mixing the carrier core particles and the polymer mixture for a sufficient period of time enabling the polymer mixture to adhere to the carrier core particles; (3) heating the mixture of carrier core particles and polymer mixture to a temperature of between about 200° F. and about 550° F., whereby the polymer mixture melts and fuses to the carrier core particles; and (4) thereafter cooling the resulting coated carrier particles wherein the polymer mixture is selected from the group consisting of polyvinylidene fluoride and polyethylene; polymethylmethacrylate and copolyethylene vinyl acetate; copolyvinylidenefluoride tetrafluoroethylene and polyethylenes; copolyvinylidenefluoride tetrafluoroethylene and copolyethylene vinyl acetate; and polymethylmethacrylate and polyvinylidene fluoride.

Claim 3

A process in accordance with claim 1 wherein the carrier core is steel.

Claim 4

A process in accordance with claim 1 wherein the carrier core is selected from the group consisting of iron and ferrites.

Claim 5

A process in accordance with claim 1 wherein the polymer mixture selected is comprised of from about 40 percent by weight to about 60 percent by weight of the first polymer, and from about 60 percent by weight to about 40 percent by weight of the second polymer.

Claim 6

A process in accordance with claim 1 wherein the triboelectric charging value of the resulting carrier particles is from about -5 microcoulombs per gram to about -80 microcoulombs per gram.

Claim 7

A process in accordance with claim 1 wherein the coating is continuous, and is present in a thickness of from about 0.2 micron to about 1.5 microns.

Claim 8

A process in accordance with claim 1 wherein the polymer mixture is heated for a period of from about 10 minutes to about 60 minutes.

Claim 9

A process in accordance with claim 7 wherein there results on the carrier a triboelectric charge of from a -8 microcoulombs per gram to a -80 microcoulombs per gram.

Claim 10

A process in accordance with claim 1 wherein the carrier core is nickel.

Claim 11

A process in accordance with claim 1 wherein the carrier core particles have an average particle diameter of between about 30 microns and about 200 microns.

Claim 12

A process in accordance with claim 1 wherein the carrier core has a surface area of at least 200 cm 2 per gram, and up to 1,000 cm 2 per gram.

Claim 13

A process in accordance with claim 1 wherein the polymer mixture adheres to the carrier core particles by impaction.

Claim 14

A process in accordance with claim 1 wherein the polymer mixture adheres to the carrier core by electrostatic attraction.

Claim 15

A developer composition comprised of the carrier particles obtained by the process of claim 1 and a toner composition comprised of toner resin particles and pigment particles.

Claim 16

A developer composition in accordance with claim 14 wherein the toner resin is comprised of styrene polymers.

Claim 17

A developer composition in accordance with claim 15 wherein the styrene polymers are selected from the group consisting of styrene methacrylates, and styrene acrylates.

Claim 18

A developer composition in accordance with claim 14 wherein the toner resin is selected from the group consisting of polyesters and styrene butadienes.

Claim 19

A developer composition in accordance with claim 14 wherein the pigment particles are carbon black.

Claim 20

A developer composition in accordance with claim 14 wherein the toner contains therein charge enhancing additives.

Claim 21

A developer composition in accordance with claim 19 wherein the charge enhancing additive is selected from alkyl pyridinium halides, organic sulfate and sulfonate compositions, and distearyl dimethyl ammonium methyl sulfate.

Claim 22

A developer composition in accordance with claim 14 wherein the core for the carrier particles is selected from the group consisting of iron, ferrites, steel and nickel.

Claim 23

A developer composition in accordance with claim 14 wherein the first polymer carrier coating is present in an amount of from about 10 percent by weight to about 90 percent by weight, and the second polymer carrier coating is present in an amount of from about 90 percent by weight to about 10 percent by weight.

Claim 24

A process for the preparation of carrier particles with substantially stable conductivity parameters which comprises (1) providing carrier cores, and a polymer mixture comprised of a first polymer and a second polymer, wherein said first and second polymers are not in close proximity in the triboelectric series, which polymer mixture is selected from the group consisting of polyvinylidene fluoride and polyethylene; polymethylmethacrylate and copolyethylene vinyl acetate; copolyvinylidenefluoride tetrafluoroethylene and polyethylenes; copolyvinylidenefluoride tetrafluoroethylene and copolyethylene vinyl acetate; and polymethylmethacrylate and polyvinylidenefluoride; (2) dry mixing the cores and the polymer mixture; (3) heating the carrier core particles and polymer mixture, whereby the polymer mixture melts and fuses to the carrier core particles; and (4) thereafter cooling the resulting coated carrier particles.

Claim 25

A process for the preparation of carrier particles with substantially stable conductivity parameters which comprises (1) providing carrier cores, and a polymer mixture comprised of a first polymer and a second polymer, wherein said first and second polymers are not in close proximity in the triboelectric series, which polymer mixture is selected from the group consisting of polyvinylidene fluoride and polyethylene; polymethylmethacrylate and copolyethylene vinyl acetate; copolyvinylidenefluoride tetrafluoroethylene and polyethylenes; copolyvinylidenefluoride tetrafluoroethylene and copolyethylene vinyl acetate; and polymethylmethacrylate and polyvinylidenefluoride; (2) dry mixing the cores and the polymer mixture; (3) heating the carrier core particles and polymer mixture, whereby the polymer mixture melts and fuses to the carrier core particles; and (4) thereafter cooling the resulting coated carrier particles.

Claim 26

A process in accordance with claim 23 wherein the dry mixing is affected for a sufficient period of time enabling the polymer mixture to adhere to the carrier core particles.

Claim 27

A process in accordance with claim 23 wherein the carrier core is steel.

Claim 28

A process in accordance with claim 23 wherein the carrier core is selected from the group consisting of iron and ferrites.

Claim 29

A process in accordance with claim 23 wherein the polymer mixture selected is comprised of from about 10 percent by weight to about 90 percent by weight of the first polymer, and from about 90 percent by weight to about 10 percent by weight of the second polymer.

Claim 30

A process in accordance with claim 23 wherein the resulting carrier particles are of a conductivity of from about 10 -6 mho-cm -1 to about 10 -17 mho-cm -1 .

Claim 31

A process in accordance with claim 23 wherein the triboelectric charging value of the resulting carrier particles is from about -5 microcoulombs per gram to about -80 microcoulombs per gram.

Claim 32

A process in accordance with claim 23 wherein the coating is continuous, and is present in a thickness of from about 0.2 micron to about 1.5 microns.

Claim 33

A process in accordance with claim 23 wherein the polymer mixture is heated for a period of about 10 minutes to about 60 minutes.

Claim 34

A developer composition comprised of the carrier particles obtained by the process of claim 23, toner resin particles and pigment particles.

Claim 35

A developer composition in accordance with claim 32 wherein the pigment particles are carbon black.

Claim 36

A developer composition in accordance with claim 32 wherein the toner resin particles are selected from the group consisting of styrene methacrylate copolymers, styrene butadiene copolymers, styrene acrylate copolymers, and polyesters.

Claim 37

A developer composition in accordance with claim 32 including therein charge enhancing additives.

Claim 38

A developer composition in accordance with claim 35 wherein the charge enhancing additives are selected from the group consisting of alkyl pyridinium halides, organic sulfate compositions, organic sulfonate compositions, and quaternary ammonium compounds.

Claim 39

A developer composition in accordance with claim 32 wherein the carrier core is selected from the group consisting of steel, iron, and ferrites.

Claim 40

A method of formulating images which comprises generating an electrostatic latent image on a photoconductive imaging member; thereafter developing this image with developer composition comprised of the carrier particles obtained by the process of claim 1 and a toner composition comprised of toner resin particles and pigment particles; subsequently transferring the developed image to a supporting substrate; and thereafter affixing the image thereto.

Claim 41

A method in accordance with claim 38 wherein fixing is accomplished by heat.

Claim 42

A method in accordance with claim 38 wherein sequential image development is accomplished by continuously generating electrostatic latent images on the imaging member and thereafter developing each of the images formed.

Claim 43

A method in accordance with claim 38 wherein developer is comprised of a toner composition with charge enhancing additives.

Claim 44

A method in accordance with claim 41 wherein the charge enhancing additives are selected from the group consisting of alkyl pyridinium halides, organic sulfate compositions, organic sulfonate compositions, and quaternary ammonium compounds.

Claim 45

A method in accordance with claim 42 wherein the charge enhancing additive is cetyl pyridinium chloride, distearyl dimethyl ammonium methyl sulfate, or stearyl phenyl dimethyl ammonium methyl tosylate.

Claim 46

A carrier composition comprised of a core with a coating thereover comprised of a powder mixture of first and second polymers which are not in close proximity in the triboelectric series, said mixture being selected from the group consisting of polyvinylidene fluoride and polyethylene; polymethylmethacrylate and copolyethylene vinyl acetate; copolyvinylidenefluoride tetrafluoroethylene and polyethylenes; copolyvinylidenefluoride tetrafluoroethylene and copolyethylene vinyl acetate; and polymethylmethacrylate and polyvinylidene fluoride wherein the triboelectric charging properties of the carrier are independent of the conductivities thereof, said triboelectric properties being dependent on the ratio of polymers present, and said conductivities being dependent on the coating weight of the polymers selected.

Claim 47

A carrier composition comprised of a core with a coating thereover comprised of a powder mixture of first and second polymers which are not in close proximity in the triboelectric series, said mixture being selected from the group consisting of polyvinylidene fluoride and polyethylene; polymethylmethacrylate and copolyethylene vinyl acetate; copolyvinylidenefluoride tetrafluoroethylene and polyethylenes; copolyvinylidenefluoride tetrafluoroethylene and copolyethylene vinyl acetate; and polymethylmethacrylate and polyvinylidene fluoride wherein the triboelectric charging properties of the carrier are independent of the conductivities thereof, said triboelectric properties being dependent on the ratio of polymers present, and said conductivities being dependent on the coating weight of the polymers selected.

Claim 48

A carrier composition in accordance with claim 44 wherein substantially constant conductivities and different triboelectric charging properties are achieved by maintaining a substantially similar coating weight on the carrier particles and modifying the ratio of polymers present.

Claim 49

A carrier composition in accordance with claim 44 which possess substantially constant triboelectric charging properties and wherein the conductivities thereof are modified by selecting a substantially constant ratio of polymers and modifying the coating weight thereof.

Claim 50

A carrier composition in accordance with claim 46 wherein the polymer ratio for the first and second polymers are from about 0.5 to about 9, and from about 9 to about 0.5.

Claim 51

A carrier composition in accordance with claim 47 wherein the polymer ratio for the first and second polymers are from about 0.5 to about 9, and from about 9 to about 0.5.

Claim 52

A carrier composition in accordance with claim 45 wherein the coating weight of the polymer mixture is from about 0.05 to about 3 weight percent.

Claim 53

A carrier composition in accordance with claim 49 wherein the coating weight of the polymer mixture is from about 0.05 to about 3 weight percent.

Claim 54

A carrier composition in accordance with claim 44 wherein the triboelectric charge is from about a -5 to about a -80 microcoulombs per gram, and wherein the carrier possesses a substantially constant conductivity.

Claim 55

A carrier composition in accordance with claim 44 wherein the conductivities thereof are from about 10 -6 mho-cm -1 to about 10 -17 mho-cm -1 , and wherein the carrier possesses a substantially constant triboelectric charging value.

Claim 56

A carrier composition in accordance with claim 44 wherein the conductivity thereof is from about 10 -6 mho-cm -1 to about 10 -17 mho-cm -1 .

Claim 57

A carrier composition in accordance with claim 44 wherein the coating weight is 1.0 percent, the carrier coating polymer mixture ratio is 9 to 1, the triboelectric charge on the carrier particles is -63 microcoulombs per gram, and the carrier particles have a conductivity of 10 -15 mho-cm -1 .

Claim 58

A carrier composition in accordance with claim 44 wherein the coating weight is 0.5 percent, the carrier coating polymer mixture ratio is 3 to 2, the triboelectric charge on the carrier particles is -29.8 microcoulombs per gram, and the carrier particles have a conductivity of 10 -14 mho-cm -1 .

Claim 59

A carrier composition in accordance with claim 44 wherein the coating weight is 0.4 percent, the carrier coating polymer mixture ratio is 7 to 3, the triboelectric charge on the carrier particles is -47.6 microcoulombs per gram, and the carrier particles have a conductivity of 10 -14 mho-cm -1 .

Claim 60

A carrier composition in accordance with claim 44 wherein the coating weight is 0.7 percent, the carrier coating polymer mixture ratio is 7 to 3, the triboelectric charge on the carrier particles is -43.0 microcoulombs per gram, and the carrier particles have a conductivity of 10 -15 mho-cm -1 .

Claim 61

A carrier composition in accordance with claim 44 with a constant triboelectric charging value.

Claim 62

A carrier composition in accordance with claim 44 with a constant conductivity.

Claim 63

A process for the preparation of carrier particles with substantially stable conductivity parameters which comprises (1) mixing carrier cores with a polymer mixture comprising from about 10 to about 90 percent by weight of a first polymer, and from about 90 to about 10 percent by weight of a second polymer, wherein said first and second polymers are not in close proximity in the triboelectric series; (2) dry mixing the carrier core particles and the polymer mixture for a sufficient period of time enabling the polymer mixture to adhere to the carrier core particles; (3) heating the mixture of carrier core particles and polymer mixture to a temperature of between about 200° F. and about 550° F., whereby the polymer mixture melts and fuses to the carrier core particles; and (4) thereafter cooling the resulting coated carrier particles wherein the polymer mixture is selected from the group consisting of polyvinylidene fluoride and polyethylene; polymethylmethacrylate and copolyethylene vinyl acetate; copolyvinylidenefluoride tetrafluoroethylene and polyethylenes; copolyvinylidenefluoride tetrafluoroethylene and copolyethylene vinyl acetate; and polymethylmethacrylate and polyvinylidene fluoride wherein the triboelectric charging properties of the carrier are independent of the conductivities thereof, said triboelectric properties being dependent on the ratio of polymers present, and said conductivities being dependent on the coating weight of the polymers selected.

Claim 64

A process for the preparation of carrier particles with substantially stable conductivity parameters which comprises (1) mixing carrier cores with a polymer mixture comprising from about 10 to about 90 percent by weight of a first polymer, and from about 90 to about 10 percent by weight of a second polymer, wherein said first and second polymers are not in close proximity in the triboelectric series; (2) dry mixing the carrier core particles and the polymer mixture for a sufficient period of time enabling the polymer mixture to adhere to the carrier core particles; (3) heating the mixture of carrier core particles and polymer mixture to a temperature of between about 200° F. and about 550° F., whereby the polymer mixture melts and fuses to the carrier core particles; and (4) thereafter cooling the resulting coated carrier particles wherein the polymer mixture is selected from the group consisting of polyvinylidene fluoride and polyethylene; polymethylmethacrylate and copolyethylene vinyl acetate; copolyvinylidenefluoride tetrafluoroethylene and polyethylenes; copolyvinylidenefluoride tetrafluoroethylene and copolyethylene vinyl acetate; and polymethylmethacrylate and polyvinylidene fluoride wherein the triboelectric charging properties of the carrier are independent of the conductivities thereof, said triboelectric properties being dependent on the ratio of polymers present, and said conductivities being dependent on the coating weight of the polymers selected.

Claim 65

A process for the preparation of carrier particles which comprises (1) providing carrier cores, and a polymer mixture comprised of a first polymer and a second polymer, wherein said first and second polymers are not in close proximity in the triboelectric series, which polymer mixture is selected from the group consisting of polyvinylidene fluoride and polyethylene; polymethylmethacrylate and copolyethylene vinyl acetate; copolyvinylidenefluoride tetrafluoroethylene and polyethylenes; copolyvinylidenefluoride tetrafluoroethylene and copolyethylene vinyl acetate; and polymethylmethacrylate and polyvinylidene fluoride; (2) dry mixing the cores and the polymer mixture; (3) heating the carrier core particles and polymer mixture, whereby the polymer mixture melts and fuses to the carrier core particles; and (4) thereafter cooling the resulting coated carrier particles wherein the triboelectric charging properties of the carrier are independent of the conductivities thereof, said triboelectric properties being dependent on the ratio of polymers present, and said conductivities being dependent on the coating weight of the polymers selected.

Claim 66

A process for the preparation of carrier particles which comprises (1) providing carrier cores, and a polymer mixture comprised of a first polymer and a second polymer, wherein said first and second polymers are not in close proximity in the triboelectric series, which polymer mixture is selected from the group consisting of polyvinylidene fluoride and polyethylene; polymethylmethacrylate and copolyethylene vinyl acetate; copolyvinylidenefluoride tetrafluoroethylene and polyethylenes; copolyvinylidenefluoride tetrafluoroethylene and copolyethylene vinyl acetate; and polymethylmethacrylate and polyvinylidene fluoride; (2) dry mixing the cores and the polymer mixture; (3) heating the carrier core particles and polymer mixture, whereby the polymer mixture melts and fuses to the carrier core particles; and (4) thereafter cooling the resulting coated carrier particles wherein the triboelectric charging properties of the carrier are independent of the conductivities thereof, said triboelectric properties being dependent on the ratio of polymers present, and said conductivities being dependent on the coating weight of the polymers selected.