Toner for developing electrostatic charged images and developer for developing electrostatic charged images, and image forming method using the same
View Patent ↗The invention provides a toner for developing electrostatic charged images comprising toner mother particles containing a binder resin and a colorant, and an external additive, wherein: the average of shape factors SF 1 of the toner mother particles represented by the following Formula (1) is 140 or less; the external additive contains higher alcohol particles having a volume-average particle diameter of 1 to 12 μm; and the content of the higher alcohol particles having a diameter equal to or less than the volume-average particle diameter of the toner mother particles is in a range of 0.15 to 2.5 parts by weight with respect to 100 parts by weight of the toner mother particles. In addition, the invention provides a developer for developing electrostatic charged images comprising the toner. Further, the invention provides an image forming method using the toner.
1. A toner for developing electrostatic images comprising toner mother particles, and an external additive, wherein:
the average of shape factors SF 1 of the toner mother particles represented by the following Formula (1) is 140 or less;
the external additive contains higher alcohol particles having a volume-average particle diameter of 1 to 12 μm; and
the content of the higher alcohol particles having a diameter equal to or less than the volume-average particle diameter of the toner mother particles is in a range of 0.15 to 2.5 parts by weight with respect to 100 parts by weight of the toner mother particles:
SF 1=( L 2 /A )×(π/4)×100 Formula (1)
wherein L represents the maximum length of each toner mother particle; and A represents the projected area of each toner mother particle.
2. A toner according to claim 1 , wherein the average of shape factor SF 1 of the higher alcohol particles is equal to or more than 140.
3. A toner according to claim 1 , wherein the higher alcohol particles has 16 to 150 carbon atoms.
4. A toner according to claim 1 , wherein a preparation of the higher alcohol particles includes pulverization.
5. A toner according to claim 1 , wherein a volume-average particle diameter of the toner mother particles is 2 to 12 μm.
6. A toner according to claim 1 , further including inorganic oxide particles having a volume-average particle diameter of 20 to 300 nm.
7. A toner according to claim 1 , further including monodisperse spherical silica having a true specific density of 1.3 to 1.9 and a volume-average particle diameter of 80 to 300 nm.
8. A toner according to claim 1 , further including monodisperse spherical silica, the standard deviation of which is a value of volume-average particle diameter D 50 multiplied by 0.22 or less.
9. A toner according to claim 1 , further including monodisperse spherical silica, the Wadell sphericity of which is 0.6 or more.
10. A developer for developing electrostatic charged images comprising a toner for developing electrostatic charged images, wherein:
the toner comprises at least toner mother particles containing a binder resin and a colorant, and an external additive;
the average of the shape factors SF 1 of the toner mother particles represented by the following Formula (1) is 140 or less;
the external additive further comprises higher alcohol particles having a volume-average particle diameter 1 to 12 μm; and
the content of the higher alcohol particles having a diameter equal to or less than the volume-average particle diameter of the toner mother particles is in a range of 0.15 to 2.5 parts by weight with respect to 100 parts by weight of the toner mother particles:
SF =( L 2 /A )×(π/4)×100 Formula (1)
wherein L represents the maximum length of each toner mother particle; and A represents the projected area of each toner mother particle.
11. A developer according to claim 10 , further comprising a resin-coated carrier.
12. A developer according to claim 10 , further comprising a carrier having the volume-average particle diameter of core materials of 10 to 100 μm.
13. An image forming method using a toner for developing electrostatic charged images, comprising:
charging a photoreceptor to form a latent image on a latent image bearing body;
developing the latent image on a developer bearing body by using the toner for developing electrostatic charged images and transferring the developed image; and
cleaning comprising removing the remaining toner on the latent image bearing body, wherein
the toner comprises at least toner mother particles containing a binder resin and a colorant, and an external additive;
the average of the shape factors SF 1 of the toner mother particles represented by the following Formula (1) is 140 or less;
the external additive further comprises higher alcohol particles having a volume-average particle diameter 1 to 12 μm; and
the content of the higher alcohol particles having a diameter equal to or less than the volume-average particle diameter of the toner mother particles is in a range of 0.15 to 2.5 parts by weight with respect to 100 parts by weight of the toner mother particles:
SF 1=( L 2 /A )×(π/4)×100 Formula (1)
wherein L represents the maximum length of each toner mother particle; and A represents the projected area of each toner mother particle.
14. An image forming method according to claim 13 , wherein charging is conducted by contact-type electrostatic charging.
15. An image forming method according to claim 13 , wherein cleaning is conducted by blade cleaning.