Developer for developing electrostatic image, image forming apparatus and image forming method

• US 20040072091A1
• Filed: 07/10/2003
• Published: 04/15/2004
• Est. Priority Date: 07/10/2002
• Status: Abandoned Application

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Umemura, Kazuhiko, Sugiura, Hideki, Nakayama, Shinya, Mochizuki, Satoshi, Asahina, Yasuo
• Application Number:
  US10/615,770
• Publication Number:
  US 20040072091A1
• Time in Patent Office: Days
• US Class Current: 430/108.7
• CPC Class Codes: G03G 9/0827 characterised by their shape, e.g. degree of sphericity
• CPC Class Codes: G03G 9/09725 Silicon-oxides; Silicates

Abstract

A developer, which includes a base toner containing at least a binding resin and a coloring agent; and inorganic fine particles; wherein the base toner satisfies 105≦SF-1≦130 and 120≦SF-2≦180, wherein SF-1=((absolute maximum length of a particle of the base toner)²/area of the particle of the base toner)×(π/4)×100, wherein SF-2=(peripheral length of the particle of the base toner)²/(area of the base toner)×(¼π)×100, wherein the inorganic fine particles have an average particle diameter that ranges between 30 nm to 160 nm.

Claims

1. A developer, comprising:

a base toner containing at least a binding resin and a coloring agent; and

inorganic fine particles;

wherein the base toner satisfies 105≦

SF-1≦

130 and 120≦

SF-2≦

180,

wherein SF-1=((absolute maximum length of a particle of the base toner)²/area of the particle of the base toner)×

(π

/4)×

100,

wherein SF-2=(peripheral length of the particle of the base toner)^2/(area of the base toner)×

(¼

π

)×

100,

wherein the inorganic fine particles have an average particle diameter that ranges between 30 nm to 160 nm.

2. The developer as claim in claim 1, wherein the inorganic fine particles are formed as silica.

3. The developer as claimed in claim 1, wherein the inorganic fine particles are applied with a sol-gel technique and are thereby formed as spherical shaped hydrophobic silica fine particles.

4. The developer as claimed in claim 1, wherein the developer contains further inorganic fine particles having an average particle diameter which is smaller than the inorganic fine particles.

5. The developer as claimed in claim 1, wherein the developer is combined with a magnetic particle to function as a carrier.

6. An image forming apparatus, comprising:

a developer for developing an electrostatic latent image formed on an electrostatic latent image carrier body to form a toner image;

a transfer unit for transferring the toner image to a transfer medium;

wherein the developer includes a further developer and a carrier,

wherein the further developer has a base toner containing at least a binding resin and a coloring agent, and inorganic fine particles,

wherein the carrier has a magnetic particle,

wherein the base toner satisfies 105≦

SF-1≦

130 and 120≦

SF-2≦

180,

wherein SF-1=((absolute maximum length of a particle of the base toner)²/area of the particle of the base toner)×

(π

/4)×

100,

wherein SF-2=(peripheral length of the particle of the base toner)^2/(area of the base toner)×

(¼

π

)×

100,

wherein the inorganic fine particles have an average particle diameter that ranges between 30 nm to 160 nm.

7. The image forming apparatus as claimed in claim 6, wherein the inorganic fine particles are formed as silica.

8. The image forming apparatus as claimed in claim 6, wherein the inorganic fine particles are applied with a sol-gel technique and are thereby formed as spherical shaped hydrophobic silica fine particles.

9. The image forming apparatus as claimed in claim 6, wherein the developer contains further inorganic fine particles having an average particle diameter which is smaller than the inorganic fine particles.

10. The image forming apparatus as claimed in claim 6, wherein the developer is combined with a magnetic particle to function as a carrier.

11. The image forming apparatus as claimed in claim 6, wherein the developer includes a plurality of colors.

12. A process cartridge, comprising:

a charge unit charging a photoconductor;

an exposure unit exposing light to the photoconductor to form an image on the photoconductor;

a development unit developing the image formed on the photoconductor with a developer;

a transfer unit transferring the image formed on the photoconductor to a transfer medium;

a cleaning unit cleaning the transfer unit;

wherein the developer includes a further developer and a carrier,

wherein the further developer has a base toner containing at least a binding resin and a coloring agent, and inorganic fine particles,

wherein the carrier has a magnetic particle,

wherein the base toner satisfies of 105≦

SF-1≦

130 and 120≦

SF-2≦

180,

wherein SF-1=((absolute maximum length of a particle of the base toner)²/area of the particle of the base toner)×

( π

/4)×

100,

wherein SF-2=(peripheral length of the particle of the base toner)^2/(area of the base toner)×

(¼

π

)×

100,

wherein the inorganic fine particle has an average particle diameter that ranges between 30 nm to 160 nm.

13. The process cartridge as claimed in claim 12, wherein the inorganic fine particles are formed as silica.

14. The process cartridge as claimed in claim 12, wherein the inorganic fine particles are applied with a sol-gel technique and are thereby formed as spherical shaped hydrophobic silica fine particles.

15. The process cartridge as claimed in claim 12, wherein the developer contains further inorganic fine particles having an average particle diameter which is smaller than the inorganic fine particles.

16. The process cartridge as claim in claim 12, wherein the developer is combined with a magnetic particle to function as a carrier.

17. A image forming method, comprising the steps of:

charging a photoconductor;

exposing light to the photoconductor to form an image on the photoconductor;

developing the image formed on the photoconductor with a developer;

transferring the image formed on the photoconductor to a transfer medium;

wherein the developer includes a further developer and a carrier,

wherein the further developer has a base toner containing at least a binding resin and a coloring agent, and inorganic fine particles,

wherein the carrier has a magnetic particle,

wherein the base toner satisfies 105≦

SF-1≦

130 and 120≦

SF-2≦

180,

wherein SF-1=((absolute maximum length of a particle of the base toner)²/area of the particle of the base toner)²×

(π

/4)×

100),

wherein SF-2=(peripheral length of the particle of the base toner/area of the base toner)×

(¼

π

)×

100,

wherein the inorganic fine particles have an average particle diameter that ranges between 30 nm to 160 nm.

18. The image forming method as claimed in claim 17, wherein the inorganic fine particles are formed as silica.

19. The image forming method as claimed in claim 17, wherein the inorganic fine particles are applied with a sol-gel technique and are thereby formed as spherical shaped hydrophobic silica fine particles.

20. The image forming method as claim in claim 17, wherein the developer contains further inorganic fine particles having an average particle diameter which is smaller than the inorganic fine particles.

21. The image forming method as claim in claim 17, wherein the developer is combined with a magnetic particle to function as a carrier.