| 摘要 |
PURPOSE:To obtain a toner good in positive or negative triboelectrifiability, superior in repeated image formation performance, small in image dependency on circumstances, and appliable to a chromatic toner by incorporating a specified metal diphosphate. CONSTITUTION:The developer is composed essentially of a colorant, a binder resin, and the metal diphosphate represented by formula I or II, R being 1-32C straight or branched hydrocarbon, M being a divalent or more valent valent metal, m being 1-6, and n being 0-5. Said metal salt is, preferably, in an amt. of 0.1-20pts.wt. per 100pts.wt. of the binder resin., and it is preferred to use a binder resin having a softening point of 90-160C deg. measurd with the Kokashiki flow tester and a glass transition point of >=50 deg.C. Such a metal diphosphate is a superior triboelectrifiability controller good in compatibility with the binder resin, and the use of it for the toner permits the toner to obtain sufficient uniform positive or negative triboelectrifiability stability against time lapse and against temps. and humidities, small rising time in triboelectrification and superior repeated image formation performance, and capability of forming sharp black and color images. |
