Patent ID: 6537715
Filing Date: 2003-03-25
Classification: G03G

Abstract:
A toner comprising toner particles containing at least (i) a binder resin, (ii) a colorant and (iii) a sulfur-containing compound selected from the group consisting of a sulfur-containing polymer and a sulfur-containing copolymer, wherein:the toner has a weight-average particle diameter of from 5 &mgr;m to 12 &mgr;m; and at least 90% of the total number of particles of the toner having a diameter of 3 &mgr;m or larger have a circularity a of 0.900 or higher as determined from the following expression (1): Circularity a=L0/Lâ€ƒâ€ƒ(1) where L0 represents the circumferential length of a circle having the same projected area as a particle image of a particle of the toner, and L represents the circumferential length of the particle image; and in which:a) the relationship between cut rate Z and toner weight-average particle diameter X satisfies the following expression (2): Cut rate Z&lE;5.3Ã—Xâ€ƒâ€ƒ(2) provided that the cut rate Z is represented by the following expression (3): Z=(1âˆ’B/A)Ã—100â€ƒâ€ƒ(3) where A is the particle concentration of the whole measured particles as measured with a flow-type particle image analyzer FPIA-1000, manufactured by Toa Iyou Denshi K. K., and B is the particle concentration of measured particles of 3 &mgr;m or larger in circle-corresponding diameter; and for the toner particles of 3 &mgr;m or larger in diameter having a number-based circularity distribution of the circularity a, the relationship between the number-based cumulative value Y of particles with a circularity a of 0.950 or higher and the toner weight-average particle diameter X satisfies the following expression (4): Number-based cumulative value Y of particles with a circularity a of 0.950 or higher&gE;exp 5.51Ã—Xâˆ’0.645â€ƒâ€ƒ(4) provided that the toner weight-average particle diameter X is from 5.0 &mgr;m to 12.0 &mgr;m; or b) the relationship between the cut rate Z and the toner weight-average particle diameter X satisfies the following expression (5): Cut rate Z>5.3Ã—Xâ€ƒâ€ƒ(5); â€ƒand for the toner particles of 3 &mgr;m or larger in diameter having a number-based circularity distribution of the circularity a, the relationship between the number-based cumulative value Y of particles with a circularity a of 0.950 or higher and the toner weight-average particle diameter X satisfies the following expression (6): â€ƒNumber-based cumulative value Y of particles with a circularity a of 0.950 or higher&gE;exp 5.37Ã—Xâˆ’0.545â€ƒâ€ƒ(6)provided that the toner weight-average particle diameter X is from 5.0 &mgr;m to 12.0 &mgr;m.