Developer, developer cartridge, developing device and image forming apparatus
A developer including a colored resin particle and an external additive added to a surface of the colored resin particle and having a diameter smaller than or equal to 200 nm is provided. The external additive includes a nitrogen-containing resin particle. In elemental analysis of the nitrogen-containing resin particle, a peak appearing in a range of 0.38-0.42 keV is expressed as an N-peak, and a peak appearing in a range of 0.48-0.52 keV is expressed as an O-peak. Maximum count numbers in the N-peak and the O-peak of the external additive on a surface of the colored resin particle are respectively expressed as N 1 and O 1 . Maximum count numbers in the N-peak and the O-peak of the surface of the colored resin particle where no external additive is observed are respectively expressed as N 2 and O 2 . The count numbers N 1 , O 1 , N 2 and O 2 satisfy 1.7×(N 2 /O 2 )<(N 1 /O 1 ).
1. A toner comprising:
a colored resin particle; and
an external additive added to a surface of the colored resin particle and having particle diameters smaller than or equal to 200 [nm], the external additive comprising nitrogen-containing resin particles,
wherein, in elemental analysis of the nitrogen-containing resin particles using an energy dispersion X-ray spectroscope, when a peak appearing in a range from 0.38 to 0.42 keV is expressed as an N-peak, a peak appearing in a range from 0.48 to 0.52 keV is expressed as an O-peak, a maximum count number in the N-peak and a maximum count number in the O-peak of the external additive on a surface of the colored resin particle are respectively expressed as N 1 and O 1 , and a maximum count number in the N-peak and a maximum count number in the O-peak of the surface of the colored resin particle where no external additive is observed are respectively expressed as N 2 and O 2 , the count numbers N 1 , O 1 , N 2 and O 2 satisfy 1.7 x (N 2 /O 2 ) <(N 1 /O 1 ), and
wherein the toner has a cohesion degree in a range from 63.7 to 80.9.
2. The toner according to claim 1 , wherein the external additive comprises silica.
3. The toner according to claim 1 , wherein the nitrogen-containing resin particles have particle diameters in a range from 60 [nm] to 185[nm].
4. The toner according to claim 1 , wherein the external additive includes a plurality of different external additives, each external additive having a mean particle diameter smaller than 200 [nm].
5. A toner cartridge comprising a storage part storing the toner according to claim 1 .
6. A developing device comprising:
a latent image bearing body;
a charging member that charges a surface of the latent image bearing body; and
a developer bearing body that bears the toner according to claim 1 , and develops a latent image on the surface of the latent image bearing body using the toner.
7. The developing device according to claim 6 , further comprising a resilient member contacting the latent image bearing body at a position upstream of the charging member and downstream of the developer bearing body in a rotating direction of the latent image bearing body.
8. An image forming apparatus comprising:
the developing device according to claim 6 ;
a transfer section that transfers a toner image formed on the surface of the latent image bearing body to a recording medium; and
a fixing section that fixes the toner image to the recording medium.
9. The image forming apparatus according to claim 8 , wherein the image forming apparatus has a configuration of a non-magnetic single-component development system.