| 摘要 |
PURPOSE:To prevent generation of a mixed color fogging by intrusion of different toners by deciding the bulk sp. gr. of a 1st toner at the bulk sp. gr. smaller than the bulk sp. gr. of the 2nd toner. CONSTITUTION:The bulk sp. gr. of the 1st toner which is so set that the electrostatic chargeability changes slightly to a reverse characteristic side than the 2nd toner by the interaction of the 1st toner and the 2nd toner is made smaller than the bulk sp. gr. of the 2nd toner. The 1st toner intruding into a 2nd developer, therefore, hardly comes into contact with a carrier by expelling the 2nd toner having the larger bulk sp. gr. and the electrostatic charge quantity thereof depends only on the interaction with the 2nd toner. The 1st toner having no electrostatic charge quantity any more scatters in the form of powder fumes to the outside of a 2nd developing device and can be removed by air suction. The color mixing is, therefore, surely prevented and the generation of the mixed color fogging is prevented as well, since such 1st toner which adheres to an electrostatic latent image (image part) hardly exists even if the 1st toner introduces into the 2nd developer. |
