Image forming method

• US 20050214671A1
• Filed: 10/13/2004
• Published: 09/29/2005
• Est. Priority Date: 03/24/2004
• Status: Active Grant

• Current Assignee: Fujifilm Business Innovation Corp. (Fujifilm Holdings Corporation), Komatsu Ltd.
• Original Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Inventors: Yano, Toshiyuki, Ninomiya, Masanobu, Mizutani, Noriyuki, Shibuya, Yuusaku
• Granted Patent: US 7,759,040 B2
• Time in Patent Office: Days
• US Class Current: 430/111.350
• CPC Class Codes: G03G 9/0819 characterised by the dimensions of the particles
• CPC Class Codes: G03G 9/0821 characterised by physical parameters magnetic parameters G03G9/083
• CPC Class Codes: G03G 9/0827 characterised by their shape, e.g. degree of sphericity
• CPC Class Codes: G03G 9/09708 Inorganic compounds
• CPC Class Codes: G03G 9/09716 treated with organic compounds
• CPC Class Codes: G03G 9/09725 Silicon-oxides; Silicates
• CPC Class Codes: G03G 9/1085 with non-ferrous metal oxide, e.g. MgO-Fe2O3
• CPC Class Codes: G03G 9/1131 Coating methods; Structure of coatings
• CPC Class Codes: G03G 9/1133 obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: G03G 9/1138 Non-macromolecular organic components of coatings
• CPC Class Codes: G03G 9/1139 Inorganic components of coatings

Abstract

A cleaner-less image forming method includes forming an electrostatic latent image on a electrostatic latent image carrying member; developing the electrostatic latent image with a developer comprising a toner and a carrier to form a toner image; and transferring the toner image. The carrier has a median of an arithmetic average height distribution of from 0.45 to 0.65 μm, and the toner includes an external additive and has an average circularity of 0.975 or more.

Claims

1. A developer for developing an electrostatic latent image, the developer comprising:

a carrier; and

a toner including an external additive,

wherein the carrier has a median of an arithmetic average height distribution of from 0.45 to 0.65 μ

m, the toner has an average circularity of 0.975 or more, and the circularity is defined by;

$\begin{array}{c}\left(\mathrm{Circularity}\right)=<br><br>\left(\mathrm{peripheral}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{length}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{of}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{equivalent}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{circle}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{diameter}\right)/\\ <br><br>\left(\mathrm{Peripheral}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{length}\right)\\ =<br><br>\left(2\times <br><br>{\left(A<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\pi <br><br>}\right)}^{1/2}\right)/\mathrm{PM}\end{array}$

where A represents a projected area of a particle, and PM represents a peripheral length of a particle.

2. The developer according to claim 1, wherein a surface of the toner has a fluctuation of an arithmetic average height of from 25 to 35.

3. The developer according to claim 1, wherein a surface of the toner has a median of an arithmetic average height distribution of from 0.05 to 0.12 μ

m.

4. The developer according to claim 1, wherein a surface of the carrier has a 90% cumulative frequency value of an arithmetic average height distribution of 0.8 μ

m or more.

5. The developer according to claim 1, wherein the carrier comprises a core material and a coating resin.

6. The developer according to claim 5, wherein the core material has a volume average particle diameter of from 10 to 55 μ

m.

7. The developer according to claim 5, wherein the core material comprises magnetic particles having a saturation magnetization at 3,000 Oe of 50 A·

m²/kg or more.

8. The developer according to claim 5, wherein the core material comprises ferrite.

9. The developer according to claim 5, wherein the coating resin contains a conductive powder.

10. The developer according to claim 9, wherein the conductive powder has a conductivity of 1×

10¹⁰ Ω

·

cm or less.

11. The developer according to claim 1, wherein the toner has a number average particle diameter of from 5.0 to 7.0 am.

13. The developer according to claim 1, wherein the external additive has a median diameter of 0.1 μ

m or more and less than 0.3 μ

m.

14. The developer according to claim 1, wherein the external additive has a fluctuation coefficient of 40% or less, and the fluctuation coefficient is defined by a ratio of an arithmetic standard deviation to an arithmetic average particle diameter.

12. A method for producing a developer containing a carrier and a toner, the method comprising:

subjecting binder resin particles and coloring agent particles to hetero aggregation in a liquid to form aggregated particles having a toner diameter; and

fusing the aggregated particles to form a toner,

wherein the carrier has a median of an arithmetic average height distribution of from 0.45 to 0.65 μ

m, and the toner has an average circularity of 0.975 or more, and the circularity is defined by;

$\begin{array}{c}\left(\mathrm{Circularity}\right)=<br><br>\left(\mathrm{peripheral}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{length}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{of}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{equivalent}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{circle}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{diameter}\right)/\\ <br><br>\left(\mathrm{Peripheral}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{length}\right)\\ =<br><br>\left(2\times <br><br>{\left(A<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\pi <br><br>}\right)}^{1/2}\right)/\mathrm{PM}\end{array}$

where A represents a projected area of a particle, and PM represents a peripheral length of a particle.

15. A cleaner-less image forming method comprising:

forming an electrostatic latent image on a electrostatic latent image carrying member;

developing the electrostatic latent image with a developer comprising a toner and a carrier to form a toner image; and

transferring the toner image,

wherein the carrier has a median of an arithmetic average height distribution of from 0.45 to 0.65 μ

m, and the toner includes an external additive and has an average circularity of 0.975 or more, and the circularity is defined by;

$\begin{array}{c}\left(\mathrm{Circularity}\right)=<br><br>\left(\mathrm{peripheral}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{length}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{of}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{equivalent}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{circle}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{diameter}\right)/\\ <br><br>\left(\mathrm{Peripheral}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{length}\right)\\ =<br><br>\left(2\times <br><br>{\left(A<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\pi <br><br>}\right)}^{1/2}\right)/\mathrm{PM}\end{array}$

where A represents a projected area of a particle, and PM represents a peripheral length of a particle.

16. The cleaner-less image forming method according to claim 15, wherein a surface of the toner has a fluctuation of an arithmetic average height of from 25 to 35.

17. The cleaner-less image forming method according to claim 15, wherein a surface of the toner has a median of an arithmetic average height distribution of from 0.05 to 0.12 μ

m.

18. The cleaner-less image forming method according to claim 15, wherein a surface of the carrier has a 90% cumulative frequency value of an arithmetic average height distribution of 0.8 μ

m or more.

19. The cleaner-less image forming method according to claim 15, wherein the external additive has a median diameter of 0.1 μ

m or more and less than 0.3 μ

m.

20. The cleaner-less image forming method according to claim 15, wherein the external additive has a fluctuation coefficient of 40% or less, and the fluctuation coefficient is defined by a ratio of an arithmetic standard deviation to an arithmetic average particle diameter.