发明授权
US6124067A Magnetic carrier, two-component developer and image forming method 有权
磁性载体,双组分显影剂和成像方法

Magnetic carrier, two-component developer and image forming method
摘要:
A magnetic carrier constituting a two-component developer for use in an electrophotographic image forming method is formed of a carrier core comprising a first resin and magnetic fine particles dispersed in the first resin, and a second resin surface-coating the carrier core. (a) The magnetic carrier has a true specific gravity of 2.5-4.5, a magnetization .sigma..sub.1000 as measured in a magnetic field of 1000.times.(10.sup.3 /4.pi.).multidot.A/m (1000 oersted) of 15-60 Am.sup.2 /kg (emu/g), a residual magnetization .sigma..sub.r of 0.1-20 Am.sup.2 /kg (emu/g) and a resistivity of 5.times.10.sup.11 -5.times.10.sup.15 ohm.cm. (b) The first resin has a polymer chain including a methylene unit (--CH.sub.2 --). (c) The second resin has at least a fluoro-alkyl unit, a methylene unit (--CH.sub.2 --) and an ester unit. (d) The carrier core is surface-coated with (i) a mixture of the second resin and a coupling agent having at least an amino group and a methylene unit, or (ii) a coupling agent having at least an amino group and a methylene unit, and then with the second resin.
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