Image forming method
View Patent ↗A cleaner-less image forming method includes forming an electrostatic latent image on a electrostatic latent image carrying member; developing the electrostatic latent image with a developer comprising a toner and a carrier to form a toner image; and transferring the toner image. The carrier has a median of an arithmetic average height distribution of from 0.45 to 0.65 μm, and the toner includes an external additive and has an average circularity of 0.975 or more.
1. A developer for developing an electrostatic latent image, the developer comprising:
a carrier comprising a core material and a coating resin; and
a toner including coloring particles which at least contain a binder resin, a coloring agent and a releasing agent, and an external additive,
wherein
the carrier has a median of an arithmetic average height distribution of from 0.45 to 0.65 μm,
the core material has a volume average particle diameter of from 10 to 55 μm,
the core material comprises magnetic particles having a saturation magnetization at 3,000 Oe of 50 A·m 2 /kg or more,
the toner has an average circularity of 0.975 or more, and
the circularity is defined by:
(
Circularity
)
=
(
peripheral
length
of
equivalent
circle
diameter
)
/
(
Peripheral
length
)
=
(
2
×
(
A
π
)
1
/
2
)
/
PM
where A represents a projected area of a particle, and PM represents a peripheral length of a particle.
2. The developer according to claim 1 , wherein a surface of the toner has a fluctuation of an arithmetic average height of from 25 to 35.
3. The developer according to claim 1 , wherein a surface of the toner has a median of an arithmetic average height distribution of from 0.05 to 0.12 μm.
4. The developer according to claim 1 , wherein a surface of the carrier has a 90% cumulative frequency value of an arithmetic average height distribution of 0.8 μm or more.
5. The developer according to claim 1 , wherein the core material comprises ferrite.
6. The developer according to claim 1 , wherein the coating resin contains a conductive powder.
7. The developer according to claim 6 , wherein the conductive powder has a conductivity of 1×10 10 Ω·cm or less.
8. The developer according to claim 1 , wherein the toner has a number average particle diameter of from 5.0 to 7.0 μm.
9. The developer according to claim 1 , wherein the external additive has a median diameter of 0.1 μm or more and less than 0.3 μm.
10. The developer according to claim 1 , wherein the external additive has a fluctuation coefficient of 40% or less, and the fluctuation coefficient is defined by a ratio of an arithmetic standard deviation to an arithmetic average particle diameter.
11. A cleaner-less image forming method comprising:
forming an electrostatic latent image on a electrostatic latent image carrying member;
developing the electrostatic latent image with a developer comprising a toner and a carrier to form a toner image, the carrier comprising a core material and a coating resin, and the toner including coloring particles which at least contain a binder resin, a coloring agent and a releasing agent, and an external additive;
transferring the toner image to a fixing substrate; and
fixing the transferred toner image to the fixing substrate by heating,
wherein
the carrier has a median of an arithmetic average height distribution of from 0.45 to 0.65 μm,
the core material has a volume average particle diameter of from 10 to 55 μm,
the core material comprises magnetic particles having a saturation magnetization at 3,000 Oe of 50 A·m 2 /kg or more,
the toner has an average circularity of 0.975 or more, and
the circularity is defined by:
(
Circularity
)
=
(
peripheral
length
of
equivalent
circle
diameter
)
/
(
Peripheral
length
)
=
(
2
×
(
A
π
)
1
/
2
)
/
PM
where A represents a projected area of a particle, and PM represents a peripheral length of a particle.
12. The cleaner-less image forming method according to claim 11 , wherein a surface of the toner has a fluctuation of an arithmetic average height of from 25 to 35.
13. The cleaner-less image forming method according to claim 11 , wherein a surface of the toner has a median of an arithmetic average height distribution of from 0.05 to 0.12 μm.
14. The cleaner-less image forming method according to claim 11 , wherein a surface of the carrier has a 90% cumulative frequency value of an arithmetic average height distribution of 0.8 μm or more.
15. The cleaner-less image forming method according to claim 11 , wherein the external additive has a median diameter of 0.1 μm or more and less than 0.3 μm.
16. The cleaner-less image forming method according to claim 11 , wherein the external additive has a fluctuation coefficient of 40% or less, and the fluctuation coefficient is defined by a ratio of an arithmetic standard deviation to an arithmetic average particle diameter.