Electrostatic-image-developing toner, method of producing the same, electrostatic image developer, image forming method and image forming apparatus

1. An electrostatic-image-developing toner, which is obtained by:

adding a phosphonic acid based sequestering agent in a particle dispersion, and then

being subject to aggregation,

wherein the phosphonic acid based sequestering agent comprises at least one of a compound represented by the following formula (1) and a compound represented by the following formula (2):

wherein each of R 1 and R 2 represents —OM, wherein M represents a hydrogen atom, an alkali metal or a quaternary ammonium;

each of R 3 , R 4 and R 5 independently represents a hydroxyl group, a carboxyl group, an alkyl or alkenyl group optionally having a hydroxyl or carboxyl group at the terminal thereof, or NR 12 R 13 , wherein each of R 12 and R 13 independently represents a hydrogen atom, an alkyl group, an alkenyl group or an acyl group, and R 12 and R 13 may be bonded together to form a ring; and

R 1 and R 2 may be the same as or different from each other,

wherein each of R 6 , R 7 , R 10 and R 11 represents —OM, wherein M represents a hydrogen atom, an alkali metal or a quaternary ammonium;

each of R 8 and R 9 independently represents a hydrogen atom, a hydroxyl group, an alkyl group, an alkenyl group or NR 12 R 13 , wherein each of R 12 and R 13 independently represents a hydrogen atom, an alkyl group, an alkenyl group or an acyl group, and R 12 and R 13 may be bonded together to form a ring; and

R 6 , R 7 , R 10 and R 11 may be the same as or different from each other, and

wherein the following requirements are satisfied:

0.05≦A≦0.5

0.40 ≦B/A ≦0.75

wherein A represents a ratio of an intensity of phosphorus element to a total intensity of all elements detected in the toner by the fluorescent X-ray analysis, and

B represents a ratio of an intensity of phosphorus element to a total intensity of all elements detected in a toner having been dispersed in an alcoholic solvent and followed by drying, by the fluorescent X-ray analysis.

2. The electrostatic-image-developing toner according to claim 1 , further comprising:

at least one of a mold releasing agent and a coloring agent.

3. The electrostatic-image-developing toner according to claim 1 , wherein

an average circularity the toner is from about 0.950 to about 0.980, and

a number ratio of particles having circularity of 0.980 or less within a particle diameter range of from 0.5 times to 0.7 times larger than a number-average particle diameter is from about 1.5% to about 15.5%.

4. An electrostatic image developer comprising:

the electrostatic-image-developing toner according to claim 1 ; and

a carrier.

5. A method of producing the electrostatic-image-developing toner according to claim 1 , comprising:

dispersing at least one of a coloring agent and a mold releasing agent to give at least one of a coloring agent dispersion and a mold releasing agent dispersion;

mixing the phosphonic acid based sequestering agent with at least one of the coloring agent dispersion and the mold releasing agent dispersion to give a phosphonic acid based sequestering agent mixture dispersion; and

mixing the phosphoric acid based sequestering agent mixture dispersion with a resin particle dispersion to aggregate and fuse the dispersed substances.

6. An image forming method comprising:

forming an electrostatic latent image on a surface of a latent image holding member;

developing the electrostatic latent image formed on the surface of the latent image holding member with a developer comprising a toner to form a toner image;

transferring the toner image formed on the surface of the latent image holding member to a surface of a transfer-receiving material; and

fixing the toner image transferred on the surface of the transfer-receiving material;

wherein

the toner is the electrostatic-image-developing toner according to claim 1 .

7. An image forming apparatus comprising:

a latent image holding member;

a charging unit that charges the latent image holding member;

an exposing unit that exposes the latent image holding member to form an electrostatic latent image on the latent image holding member;

a development unit that develops the electrostatic latent image with a developer to form a toner image; and

a transfer unit that transfers the toner image on the latent image holding member to a recording material;

wherein the developer comprises the electrostatic-image-developing toner according to claim 1 .