Toner for electrostatic image development, developer for electrostatic image development, developer cartridge, process cartridge, and image-forming apparatus, and image-forming method

1. A toner for electrostatic image development comprising:

a toner particle containing a polyester resin and a coloring agent; and

an uncolored particle containing a polyester resin and not containing a coloring agent,

wherein

a ratio of an amount of a Sn element contained in the uncolored particle to an amount of a Sn element contained in the toner particle is from 1.1 to 3.0,

a shape factor SF1 of the uncolored particles is 110 or less, and

a number of the uncolored particles is 50 or less based on 5,000 toner particles.

2. The toner for electrostatic image development as claimed in claim 1 , wherein the Sn element contained in the uncolored particle is a tin compound catalyst used in polymerization of the polyester resin.

3. The toner for electrostatic image development as claimed in claim 1 , wherein an alkenylsuccinic acid is contained as a constitutional component of the polyester resin contained in both the toner particle and the uncolored particle.

4. The toner for electrostatic image development as claimed in claim 1 , wherein a weight average molecular weight Mw of the polyester resins contained in both the toner particle and the uncolored particle is 5,000 or more.

5. The toner for electrostatic image development as claimed in claim 1 , wherein

the toner particle comprises a release agent, and

a content of the release agent is from 1 part by weight to 10 parts by weight with respect to 100 parts by weight of the polyester resin contained in the toner particle.

6. The toner for electrostatic image development as claimed in claim 1 , which has a volume average particle size of from 4 μm to 8 μm.

7. The toner for electrostatic image development as claimed in claim 1 , which has a volume average particle size distribution index GSD v of 1.27 or less.

8. The toner for electrostatic image development as claimed in claim 1 , which has a shape factor SF1 of 110 or more and 140 or less.

9. A developer for electrostatic image development comprising the toner as claimed in claim 1 .

10. An image-forming method comprising:

a charging process for charging a surface of an image holding member;

a latent image-forming process for forming an electrostatic latent image on the surface of the image holding member;

a developing process for forming a toner image by developing the electrostatic latent image formed on the surface of the image holding member with a developer; and

a transfer process for transferring the developed toner image to a transfer-receiving material;

wherein the developer is the developer for electrostatic image development as claimed in claim 9 .