| 摘要 |
PURPOSE:To increase image density and to obtain a sharp image without development fogging and scattering of a toner to the periphery of the latent image edge by incorporating specific zinc dithiocarbamic acid into a developer. CONSTITUTION:The zinc dithiocarbomate expressed by the formula (R1, R2 are respectively lower alkyl or phenyl, alkyl phenyl of 1-4 carbon atoms) is incorporated into a developer as a positive electrification controlling agent. The method for incorporating the same into the developer may be either of a method for adding the same into the developer or a method for adding externally the same to the developer. The zinc dithiocarbamate is preferably used at 0.5- 50pts.wt. with 100pts.wt. the resin in the case of internal addition and about 0.01-40pts.wt. with 100pts.wt. the resin in the case of external addition. The quantity of electrification can be adequately controlled and fogging and scattering of the toner to the periphery of the latent image edges are prevented by using such zinc dithiocarbamate, by which the high image density is obtd. and the reproducibility of halftone is improved. Since the dithiocarbamic acid is white and is therefore suitable for obtaining a sharp color image and since said acid itself has stability with heat and time and low hygroscopicity, the image stable for a long period of time is obtd. |
