Claims
- 1. A negatively chargeable toner, comprising:
toner particles prepared by means of a wet granulation method; and external additives externally added to the toner particles, wherein the external additives comprises a first hydrophobic silica having a mean primary particle size of 5 nm to 18 nm, a second hydrophobic silica having a mean primary particle size of 18 nm to 50 nm, which is greater than that of the first hydrophobic silica, and a hydrophobic titanium oxide having a mean primary particle size of 10 nm to 40 nm.
- 2. The toner according to claim 1, wherein said toner particles are gained by coagulating particles in a particle dispersion liquid where particles including at least resin particles are dispersed in an aqueous medium and by heating and fusing the coagulated particles.
- 3. The toner according to claim 1, wherein the toner particles do not include a charge control agent.
- 4. The toner according to claim 1, wherein inorganic fine particles having a mean primary particle size of 80 nm to 1200 nm are externally added to the negatively chargeable toner.
- 5. The toner according to claim 4, wherein said inorganic fine particles have a mean primary particle size of 100 nm to 800 nm.
- 6. The toner according to claim 4, wherein said inorganic fine particles are strontium titanate.
- 7. The toner according to claim 1, wherein a fatty acid metal salt is externally added to said negatively chargeable toner.
- 8. The toner according to claim 7, wherein the fatty acid metal salt is calcium stearate.
- 9. The toner according to claim 1, wherein the first hydrophobic silica has a mean primary particle size of 5 nm to 16 nm, the second hydrophobic silica has a mean primary particle size of 20 nm to 35 nm and the hydrophobic titanium oxide has a mean primary particle size of 15 nm to 30 nm.
- 10. The toner according to claim 1, wherein the addition amount of the first hydrophobic silica is 0.05 to 2 parts by weight, the addition amount of the second hydrophobic silica is 0.1 to 2 parts by weight and the addition amount of the hydrophobic titanium oxide is 0.1 to 2 parts by weight relative to the 100 parts by weight of toner particles.
- 11. A full color toner that is negatively chargeable and utilized for a full color image-forming apparatus, comprising:
toner particles prepared by means of a wet granulation method; and external additives externally added to the toner particles, wherein the external additives comprises a first hydrophobic silica having a mean primary particle size of 5 nm to 18 nm, a second hydrophobic silica having a mean primary particle size of 18 nm to 50 nm, which is greater than that of the first hydrophobic silica, and a hydrophobic titanium oxide having a mean primary particle size of 10 nm to 40 nm.
- 12. The toner according to claim 11, wherein said toner particles are gained by coagulating particles in a particle dispersion liquid where particles, including, at least, resin particles, are dispersed in an aqueous medium and by heating and fusing the coagulated particles.
- 13. The toner according to claim 11, wherein the toner particles do not include a charge control agent.
- 14. The toner according to claim 11, wherein inorganic fine particles having a mean primary particle size of 80 nm to 1200 nm are externally added to the negatively chargeable toner.
- 15. The toner according to claim 11, wherein said first hydrophobic silica has a mean primary particle size of 5 nm to 16 nm, said second hydrophobic silica has a mean primary particle size of 20 nm to 35 nm and said hydrophobic titanium oxide has a mean primary particle size of 15 nm to 30 nm.
- 16. The toner according to claim 11, wherein a fatty acid metal salt is externally added to said negatively chargeable toner.
- 17. The toner according to claim 11, in which the full color image-forming apparatus comprises the steps of:
forming a full color toner image, wherein the step of forming a toner image on an electrostatic latent image-support member and transferring this toner image from the electrostatic latent image-support member to an intermediate transfer member by means of a primary transfer roller is sequentially carried out for each of the predetermined color so that toner images of the respective colors are overlapped on the intermediate transfer member; transferring said full color toner image on the intermediate transfer member from the intermediate transfer member to a recording medium by means of a secondary transfer roller at a portion where the intermediate transfer member is supported by a support roller; and fixing the transferred full color toner image on the recording medium.
- 18. The toner according to claim 11, wherein the full color image-forming apparatus comprising:
a first image formation unit for transferring a first toner image to an intermediate transfer member; a second image formation unit for transferring a second toner image of a color differing from that of the first toner image to said intermediate transfer member; a third image formation unit for transferring a third toner image of a color differing from those of said first and second toner images to said intermediate transfer member; and a fourth image formation unit for transferring a fourth toner image of a color differing from those of said first to third toner images to said intermediate transfer member.
- 19. The toner according to claim 18, wherein said first to fourth image formation units are placed beneath the intermediate transfer member.
- 20. A full color image-forming method, wherein the full color negatively chargeable toner according to claim 11 is utilized, comprising the steps of:
forming a full color toner image by overlapping first to fourth toner images on an intermediate transfer member through the steps of: forming a first toner image on a first electrostatic latent image-support member and transferring this first toner image from said first electrostatic latent image-support member to the intermediate transfer member by means of a first primary transfer roller; forming a second toner image of a color differing from that of said first toner image on a second electrostatic latent image-support member and transferring this second toner image from said second electrostatic latent image-support member to the intermediate transfer member by means of a second primary transfer roller; forming a third toner image of a color differing from those of said first and second toner images on a third electrostatic latent image-support member and transferring this third toner image from said third electrostatic latent image-support member to the intermediate transfer member by means of a third primary transfer roller; and forming a fourth toner image of a color differing from those of said first to third toner images on a fourth electrostatic latent image-support member and transferring this fourth toner image from said fourth electrostatic latent image-support member to the intermediate transfer member by means of a fourth primary transfer roller; transferring the full color toner image on the intermediate transfer member from the intermediate transfer member to a recording medium by means of a secondary transfer roller at a portion where the intermediate transfer member is supported by a support roller; and fixing the transferred full color toner image on the recording medium.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2002-002207 |
Jan 2002 |
JP |
|
Parent Case Info
[0001] This application is based on an application No. 2002-002207 filed in Japan, the contents of which are hereby incorporated by reference.