Resin-coated carrier for electrophotographic developer and electrophotographic developer using the resin-coated carrier
Provided is a resin-coated carrier for an electrophotographic developer, wherein the surface of a magnetic particle is coated with a mixed resin composed of two resins, and when the two resins are denoted by the resin 1 and the resin 2 , respectively, the relative difference between the respective adsorbed moisture amounts of the resin 1 and the resin 2 at a temperature of 30° C. and a relative humidity of 80% satisfies the following formula (1): 1≦| ax−b (100− x )|≦10 (1) a: the adsorbed moisture content (% by weight) of the resin 1 b: the adsorbed moisture content (% by weight) of the resin 2 x: the content percentage of the resin 1 (0<x<100).
1. A resin-coated carrier for an electrophotographic developer, wherein the surface of a magnetic particle is coated with a mixed resin composed of two resins, and when the two resins are denoted by the resin 1 and the resin 2 , respectively, the relative difference between the respective adsorbed moisture amounts of the resin 1 and the resin 2 at a temperature of 30° C. and a relative humidity of 80% satisfies the following formula (1):
1≦| ax−b (100− x )|≦10 (1)
a: the adsorbed moisture content (% by weight) of the resin 1
b: the adsorbed moisture content (% by weight) of the resin 2
x: the content percentage of the resin 1 (0<x<100).
2. The resin-coated carrier for an electrophotographic developer according to claim 1 , wherein the sum of the respective adsorbed moisture amounts of the resin 1 and the resin 2 satisfies the following formula (2):
2≦ ax+b (100− x )≦20 (2)
a: the adsorbed moisture content (% by weight) of the resin 1
b: the adsorbed moisture content (% by weight) of the resin 2
x: the content percentage of the resin 1 (0<x<100).
3. An electrophotographic developer comprising the resin-coated carrier according to claim 2 and a toner.
4. The resin-coated carrier for an electrophotographic developer according to claim 1 , wherein the element Fe derived from the resins is contained in the mixed resin in a total amount of 0.2 to 1.9% by weight.
5. An electrophotographic developer comprising the resin-coated carrier according to claim 4 and a toner.
6. The resin-coated carrier for an electrophotographic developer according to claim 1 , wherein the coating of the mixed resin is performed by dry coating.
7. An electrophotographic developer comprising the resin-coated carrier according to claim 6 and a toner.
8. An electrophotographic developer comprising the resin-coated carrier according to claim 1 and a toner.
9. The resin-coated carrier for an electrophotographic developer according to claim 1 , wherein the two resins are selected from a straight silicone resin, an acrylic resin, a styrene resin, a polyester resin, an epoxy resin, a polyamide resin, a polyamideimide resin, an alkyd resin and a fluororesin.