Electrophotographic toner with uniformly dispersed wax
View Patent ↗Toner particles are described containing at least one toner resin and at least one wax. The wax present in the toner particles has an average domain size of about 1 micron or less. Developer systems, two component and monocomponent, are further described as well development systems and methods for developing an electrostatic image.
1. Toner particles comprising a composition consisting of at least one toner resin melt-compounded with at least one wax, wherein said at least one wax has an average domain size in the toner particles of about 1 micron or less, and wherein said toner particles are negative charging toner particles.
2. The toner particles of claim 1 , wherein said average domain size is from about 0.1 to about 1 micron.
3. The toner particles of claim 1 , wherein said average domain size is from about 0.1 to about 0.5 micron.
4. The toner particles of claim 1 , wherein said average domain size is from about 0.5 micron or less.
5. The toner particles of claim 1 , wherein said average domain size is from about 0.05 to about 1 micron.
6. The toner particles of claim 1 , further comprising at least one surface treatment agent.
7. The toner particles of claim 6 , wherein said surface treatment agent comprises silica.
8. The toner particles of claim 1 , further comprising at least one colorant, at least one charge agent, at least one surface agent, or combinations thereof.
9. The toner particles of claim 1 , wherein said toner resin comprises cross-linked styrene acrylate or cross-linked polyester or derivatives thereof.
10. The toner particles of claim 1 , wherein said wax comprises polyethylene.
11. The toner particles of claim 1 , wherein said wax comprises at least one polyolefin wax.
12. A two component developer comprising the toner particles of claim 1 and carrier particles.
13. The two component developer of claim 12 , wherein said carrier particles are hard carrier particles.
14. A monocomponent developer comprising the toner particles of claim 1 , wherein said toner particles further comprise charging particles present in said toner particles.
15. A development system for toner comprising:
a supply of dry developer mixture comprising the toner particles of claim 1 and hard magnetic carrier particles;
a non-magnetic, cylindrical shell for transporting the developer from said supply to a development zone, wherein said shell is rotatable or stationary;
a rotating magnetic core of a pre-selected magnetic field strength;
means for rotating at least said magnetic core to provide for the transport of said toner particles from said shell to an electrostatic image.
16. The development system of claim 15 , wherein said toner particles have a spacing agent on the surface of said toner particles.
17. The development system of claim 16 , wherein said spacing agent comprises silica.
18. A method for developing an electrostatic image with the toner particles of claim 1 comprising developing an electrostatic image member bearing an electrostatic image pattern by moving the image member through a development zone and transporting developer through the development zone in developing relation with the charge pattern of the moving imaging member by rotating an alternating-pole magnetic core of a pre-selected magnetic field strength within an outer non-magnetic shell, which is rotating or stationary, and controlling the directions and speeds of the core and optionally the shell rotations so that developer flows through the development zone in a direction co-current with the image member movement, wherein said developer comprises charged toner particles of claim 1 and oppositely charged hard magnetic carrier particles.
19. The toner particles of claim 1 , wherein said toner resin comprises a polyester.
20. The toner particles of claim 1 , wherein said toner resin comprises a polyester synthesized from a bisphenol diol and a polycarboxylic acid.
21. A method of making the toner particles of claim 1 comprising melt-compounding at least one toner resin and at least one wax together wherein during melt-compounding, the melt viscosity of said wax and the melt viscosity of said toner resin are at a ratio of 1/10 or greater.
22. The method of claim 21 , wherein said ratio is from about 1/10 to about 10/10.
23. The method of claim 21 , wherein said ratio is from about 4/10 to about 10/10.
24. A method of making the toner particles of claim 1 comprising melt-compounding at least one toner resin and at least one wax together at a temperature such that the melt viscosities of said wax and said toner resin are at the closest to each other.