Patent ID: 8039190

Claim:
A carrier core material for an electrophotographic developer comprising Li ferrite, maghemite, and Fe 3 O 4 , wherein a part thereof is substituted with Mn, Li content is 1 to 2.5% by weight, Mn content is 2 to 7.5% by weight, and silicon content is 25 to 10,000 ppm, the following equation (1) is satisfied when respective integrated strengths of spinel crystal structure (110), (210), (211), and (311) faces in X-ray diffraction are respectively I 110 , I 210 , I 211 , and I 311 , a resistivity R 50 of 50 V across a 6.5 mm gap is 5×10 7 to 7×10 8 Ω, and a resistivity R 1000 of 1,000 V across a 6.5 mm gap is 1×10 7 to 8×10 8 Ω 2<100×( I 110 +I 210 +I 211 )/ I 311 <14 (1).