Magnetic toner
First Claim
1. A magnetic toner comprising magnetic toner base particles each containing at least a binder resin and magnetic iron oxide, wherein:
- (i) the binder resin contains a polyester unit;
(ii) the toner has a weight average particle size (D4) of 5.0 to 9.0 μ
m;
(iii) the toner has a true specific gravity of 1.34 to 1.56 g/cm3;
(iv) the toner has a saturated magnetization of 20 to 35 Am2/kg in a magnetic field of 796 kA/m;
(v) the toner contains 60 number % or more of toner having a circularity of 0.93 or more; and
(vi) a dielectric loss tangent (tan δ
) of the toner at 100 kHz satisfies the following formula (I);
(tan δ
H−
tan δ
L)/tan δ
L<
0.20
(1)wherein tan δ
H represents a dielectric loss tangent of the toner at a glass transition temperature (°
C.)+10°
C. and tan δ
L represents a dielectric loss tangent of the toner at the glass transition temperature (°
C.)−
10°
C.
1 Assignment
0 Petitions
Accused Products
Abstract
To provide a magnetic toner which: enables a stable image density to be obtained irrespective of a use environment; and exhibits excellent low-temperature fixability, little image deterioration upon fixation, high coloring power, and a reduced toner consumption. The present invention relates to a magnetic toner containing at least: a binder resin; and a magnetic body. The binder resin contains a polyester unit. The toner has a weight average particle size of 5.0 to 9.0 μm, a true specific gravity of 1.3 to 1.7 g/cm3, and a saturated magnetization of 20 to 35 Am2/kg in a magnetic field of 796 kA/m. The dielectric loss tangent (tan δ) of the toner satisfies (tan δH−tan δL)/tan δL≦0.20 at 100 kHz.
-
Citations
7 Claims
-
1. A magnetic toner comprising magnetic toner base particles each containing at least a binder resin and magnetic iron oxide, wherein:
-
(i) the binder resin contains a polyester unit; (ii) the toner has a weight average particle size (D4) of 5.0 to 9.0 μ
m;(iii) the toner has a true specific gravity of 1.34 to 1.56 g/cm3; (iv) the toner has a saturated magnetization of 20 to 35 Am2/kg in a magnetic field of 796 kA/m; (v) the toner contains 60 number % or more of toner having a circularity of 0.93 or more; and (vi) a dielectric loss tangent (tan δ
) of the toner at 100 kHz satisfies the following formula (I);
(tan δ
H−
tan δ
L)/tan δ
L<
0.20
(1)wherein tan δ
H represents a dielectric loss tangent of the toner at a glass transition temperature (°
C.)+10°
C. and tan δ
L represents a dielectric loss tangent of the toner at the glass transition temperature (°
C.)−
10°
C.- View Dependent Claims (2, 3, 4, 5, 6, 7)
-
Specification