Magnetic carrier and two-component developer
First Claim
1. A magnetic carrier of which a resin-filled core is coated with a vinyl-resin, the resin-filled core having a porous ferrite particle in pores of which a resin is filled, whereinthe porous ferrite particlei) has a resistivity at 100 V/cm of from at least 8.0×
- 104 Ω
·
cm to not more than 5.0×
106 Ω
·
cm,ii) contains an oxide of Mg in the range from at least 1.00 mass % to not more than 15.00 mass % as MgO with reference to the mass of the porous ferrite particle, andiii) contains an oxide of Sr and an oxide of Ca, with a total content of these oxides of from at least 0.20 mass % to not more than 3.00 mass % as SrO and CaO with reference to the mass of the porous ferrite particle, and whereinin a backscattered electron projection image of the magnetic carrier obtained by using a scanning electron microscope at an acceleration voltage of 2.0 kV, the magnetic carrier has a total area for regions originating from the porous ferrite particle of from at least 0.2 area % to not more than 5.0 area % with reference to the projected area of the magnetic carrier.
1 Assignment
0 Petitions
Accused Products
Abstract
The present invention provides a magnetic carrier that can stably impart charge to a toner on a long term basis and that exhibits an excellent toner separation property and thus exhibits an excellent developing performance. This magnetic carrier is a magnetic carrier in which a vinyl resin coats the surface of a resin-filled core in which a resin is filled in pores of a porous ferrite particle, wherein the resistivity, Mg content, and total content of Sr and Ca oxides of the porous ferrite particle exhibit prescribed values and the magnetic carrier has a total area—in the backscattered electron projection image obtained by observation using a scanning electron microscope at an acceleration voltage of 2.0 kV—for a region originating with the porous ferrite particle of from at least 0.2 area % to not more than 5.0 area % with reference to the projected area of the magnetic carrier.
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Citations
10 Claims
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1. A magnetic carrier of which a resin-filled core is coated with a vinyl-resin, the resin-filled core having a porous ferrite particle in pores of which a resin is filled, wherein
the porous ferrite particle i) has a resistivity at 100 V/cm of from at least 8.0× - 104 Ω
·
cm to not more than 5.0×
106 Ω
·
cm,ii) contains an oxide of Mg in the range from at least 1.00 mass % to not more than 15.00 mass % as MgO with reference to the mass of the porous ferrite particle, and iii) contains an oxide of Sr and an oxide of Ca, with a total content of these oxides of from at least 0.20 mass % to not more than 3.00 mass % as SrO and CaO with reference to the mass of the porous ferrite particle, and wherein in a backscattered electron projection image of the magnetic carrier obtained by using a scanning electron microscope at an acceleration voltage of 2.0 kV, the magnetic carrier has a total area for regions originating from the porous ferrite particle of from at least 0.2 area % to not more than 5.0 area % with reference to the projected area of the magnetic carrier. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
- 104 Ω
Specification