Electrophotographic toner, process for producing the same, and process for forming image

1. An electrophotographic toner comprising:

a binder resin; and

a colorant,

wherein:

log 10 {[Cu]/[C]} is satisfactory witgh the following equation (1):

−5.0≦log 10 {[Cu]/[C]}−3.5  (1)

wherein

[C] represents a carbon content (%) measured with fluorescent X-ray, and [Cu] represents a copper content (%) measured with fluorescent X-ray.

2. The electrophotographic toner according to claim 1 , wherein the colorant contains at least one of a pigment of a yellow colorant, a pigment of a magenta colorant, a dye of a yellow colorant, and a dye of a magenta colorant.

3. The electrophoto graphic toner according to claim 1 , wherein the colorant is an organic colorant having a chromophoric group selected from the group consisting of an anisidino group, an anisoyl group, an anilino group, an isoquinolyl group, an isonicotinoyl group, an isophthaloyl group, an indolyl group, a quinolidino group, a xanthenyl group, a xylyl group, a quinolyl group, a salicylidene group, a salicyl group, a salicyloyl group, a diphenylamino group, a diphenylmethylene group, a cinnamyl group, a cinnamoyl group, a styryl group, a sulfanylyl group, a sulfanylamide group, a toluidino group, a toluoyl group, a naphthylazo group, a naphthyloxy group, a naphthoyl group, a naphthoyloxy group, a nicotinoyl group, a piperidino group, a piperidyl group, a piperonyl group, a pimeloyl group, a pyrazinyl group, a pyrazonyl group, a pyrazolyl group, a pyranyl group, a pyridinio group, a pyridyl group, a pyridyloxy group, a 2-pyridinecarbonyl group, a pyrimidinyl group, a pyrrolidinyl group, a pyrrolinyl group, a pyrrolyl group, a phenylazo group, a phenylimino group, a phenylcarbamoyl group, a phenylsulfamoyl group, a phenylsulfinyl group, a phenylsulfonylamino group, a phenylthio group, a phenylacetyl group, a phenacylidene group, a phenacyl group, a phthalidylidene group, a phthalidyl group, a phthalimide group, a phthaloyl group, a furyl group, a fluorenyl group, a fluorenylidene group, a benzilidene group, a benzyloxy group, a benzyloxycarbonyl group, a benzylthio group, a benzamide group, a benzimidoyl group, a benzhydrilidene group, a benzoylimino group, a benzoyloxy group, a benzoquinonyl group and a benzofuranyl group.

4. The electrophotographic toner according to claim 1 , wherein the colorant contains at least one of a monoazo pigment, a benzimidazolone pigment, a disazo condensation pigment, an isoindolinone pigment, an anthraquinone pigment, a disazo pigment, an azolake pigment and an quinophthalone pigment.

5. The electrophotographic toner according to claim 1 , wherein a compound exhibiting a copper strength is an inorganic copper compound.

6. The electrophotographic toner according to claim 1 , wherein a compound exhibiting a copper strength is an inorganic copper compound, and the inorganic copper compound is water soluble.

7. The electrophotographic toner according to claim 1 , wherein a compound exhibiting a copper strength is an inorganic copper compound, and a copper atom of the inorganic copper compound is monovalent.

8. The electrophotographic toner according to claim 1 , wherein GSDp is of 1.23 or less,

where

GSDp represents a particle size distribution of the electrophotographic toner.

9. The electrophotographic toner according to claim 1 , wherein a shape factor SF1 of the electrophotographic toner is from 110 to 140.

10. The electrophoto graphic toner according to claim 1 , further comprising a releasing agent.

11. The electrophotographic toner according to claim 1 , further comprising an ultraviolet absorbent.

12. The electrophotographic toner according to claim 1 , further containing water in an amount of from 0.3 to 3.0% based on the total weight of the electrophotographic toner.

13. A method for producing for producing an electrophotographic toner comprising:

aggregating binder resin particles having a particle diameter of 1 μm or less and a colorant to form aggregated particles having a diameter of a toner particle diameter by mixing a binder resin particle dispersion liquid having the binder resin particles dispersed therein and a colorant dispersion liquid having the colorant dispersed therein; and

fusing the aggregated particles to form toner particles by heating to a temperature equal to or higher than a glass transition temperature of the binder resin particles,

wherein

a copper compound is made present in at least one of the aggregating and the fusing for controlling a carbon content [C] (%) and a copper content [Cu] (%) measured with fluorescent X-ray to satisfy the following equation (1):

−5.0≦log 10 {[Cu]/[C]}≦−3.5  (1).

14. The method according to claim 13 , further comprising aggregating the binder resin particle dispersion liquid and the colorant dispersion liquid along with a copper compound.

15. The method according to claim 13 , further comprising aggregating the binder resin particle dispersion liquid and the colorant dispersion liquid along with a copper compound and an ultraviolet absorbent.

16. The method according to claim 13 , wherein the toner is controlled to contain water in an amount of from 0.3 to 3.0% based on the total weight of the toner.

17. An electrophotographic developer comprising:

an electrophotographic toner; and

a carrier,

wherein the electrophotographic toner includes:

a binder resin; and

a colorant,

wherein log 10 {[Cu]/[C]} is satisfactory with the following equation (1):

−5.0≦log 10 {[Cu]/[C]}≦−3.5  (1)

wherein

[C] represents a carbon content (%) measured with fluorescent X-ray, and [Cu] represents a copper content (%) measured with fluorescent X-ray.

18. The electrophotographic developer according to claim 17 , wherein the colorant contains at least one of a monoazo pigment, a benzimidazolone pigment, a disazo condensation pigment, an isoindolinone pigment, an anthraquinone pigment, a disazo pigment, an azolake pigment and an quinophthalone pigment.

19. The electrophotographic developer according to claim 18 , wherein a compound exhibiting a copper strength is an inorganic copper compound.