| 摘要 |
PURPOSE:To obtain a developer which is stable and uniform in the quantity of frictional electrostatic charging, is free from photographic fogs, and scattering and cohesion of the toner, increases the number of enduring copies and has a high transfer effect at high humidity by permitting fine silicic acid powder synthesized by a wet method to be contained. CONSTITUTION:The fine powder of the silicic acid which is synthesized by a wet method, and is of 6-11 pH dispersed at 4wt% in distilled water is contained in a developer. The fine powder of the silicic acid of 0.01-2mum average primary grain sizes is used, and the amt. of its application is preferably 0.01-20% base on the weight of the developer. For example, 100pts. polystyrene resin, 5pts. carbon black, and 5pts. methylene blue chloride are kneaded with hot rolls, after which the mixture is pulverized to 10-20mum average grain sizes. 1.0pt.wt. said fine silicic acid powder is added to this and is mixed with a Henschel mixer. 100pts. iron powder carrier of 50-80mum average grain sizes is added to 5pts. the mixture prepd. by this, and these are mixed, whereby the developer is obtained. |
