| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a magnetic black toner having easily adjustable luster and capable of forming a high grade image having moderate luster with high transfer efficiency. SOLUTION: This magnetic black toner contains 1st inorg. fine powder besides magnetic black toner particles contg. a bonding resin, 30-200 pts.wt. magnetic substance based on 100 pts.wt. of the bonding resin and 1st solid wax having the main heat absorption peak by DSC in the range of 60-120 deg.C. The ratio (Mw/Mn) of the wt. average mol.wt. Mw of the wax to the number average mol.wt. Mn is 1.0-2.0. In the mol.wt. distribution of the THF-soluble component of the bonding resin, the content (M1) of a part whose mol.wt. is <50,000 is 40-70%, the content (M2) of a part whose mol.wt. is 50,000-500,000 is 20-45%, the content (M3) of a part whose mol.wt. is >500,000 is 2-25% and the relation of M1>=M2>M3 is satisfied. The ratio of the viscoelasticity tanδof the bonding resin at 150 deg.C to that at 100 deg.C is >=1 and the values Emin and Emax at 150-190 deg.C are in the range of 0.5-3.0.</p> |
