| 摘要 |
There is described a negative charge control agent for use in electroreprography which comprises one or more pyrazolones of Formula (I), which includes all electroreprographically effective forms of such compounds selected from one ore more of the following (including mixtures thereof and combinations thereof in the same species): stereoisomers, zwitterions, polymorphs, solvates, isotopic forms; and salts thereof; where in Formula (I): R<1>, R<2> and R<3> each independently represents one or more substituents selected from one or more of: H, hydroxy, mercapto, amino, nitro, sulpho, sulpheno, sulphino, carboxy, halo, cyano, optionally substituted C1-30 hydrocarbyl. |
