| 摘要 |
PURPOSE:To enable the black ground of a wide area and the black ground of a narrow area to be both developed with good reproducibility by providing the carrier of which the resistivity when a 10V/cm DC electric field is applied to 5-15 timee the resistivity when a 100V/cm DC electric field is applied. CONSTITUTION:The carrier of which the resistivity value when a 10V/cm DC electric field is applied is 10<8>-10<11>OMEGA.cm, the resistivity value when a 100V/cm DC electric field is applied is 10<7>-10<10>OMEGA.cm and the former is 5-15 times the latter is used. Such carrier is obtained by adding reduced iron powder into the water added with, for example, a silane coupling agent and controlled to 4.0pH with an acetic acid, and sticking a cationic conductivity imparting material to the heat- treated iron powder. By the use of the carrier, the formation of blank-out etc. on the black ground of a wide area is eliminated, and the narrow balck ground of characters, line images, etc. is reproduced faithfully to the oringial. In addition, the occurrence of the deterioration of the carrier after copying of multiple sheets is made difficult. |
