| abstract |
A toner comprising toner particles having at least one type of surface additive, the toner particles having an FPIA average circularity of at least 0.95, whereby at least 80% wt of the total amount of surface additives stays onto the surface of the toner particles when an ultrasonic treatment of 4500 to 4700 J/gram of toner is applied; a substrate printed or marked with the above-described toner; and a method for manufacturing a toner, said method including the steps of: mixing a binder resin, a colorant and optionally other additives, thereby forming a mixture, melting, kneading and milling said mixture, thereby obtaining a melted kneaded product, pulverizing said melted kneaded product, adding at least one surface additive before or while bringing the FPIA average circularity of said toner particles to 0.95 by modifying the shape or surface of said particles, wherein the total amount of surface additive does not exceed 2% wt of toner particles, whereby at least 80% wt of the total amount of surface additive stays on the surface of the toner particles when an ultrasonic treatment of 4500 to 4700 J/gram of toner is applied. |