Toner compositions
View Patent ↗A toner having charge control agents which impart excellent triboelectric charging characteristics. In embodiments, the toner particles are made by a process in which the toner particles are made without a shell which provides homogenous distribution of the charge control agents, providing a toner with higher charge and better environmental stability.
1. A toner comprising
shell-less toner particles comprising
a core portion comprising a resin, wax and colorant, and
a charge control agent distributed homogenously throughout the core portion, wherein a bulk level of the charge control agent in the core portion is from about 0.1 to about 50 percent by weight of the total weight of the toner particle and a surface level of the charge control agent on the core portion is from about 0.01 to about 10 percent by weight of the total weight of the toner particle.
2. The toner of claim 1 , wherein toner is an emulsion aggregation toner.
3. The toner of claim 1 , wherein the charge control agent is selected from the group consisting of metal complexes of alkyl derivatives of acids such as salicylic acid, dicarboxylic acid derivatives, benzoic acid, oxynaphthoic acid, and sulfonic acids, or other complexes such as polyhydroxyalkanoate quaternary phosphonium trihalozincate, and metal complexes of dimethyl sulfoxide, and mixtures thereof.
4. The toner of claim 1 , wherein the charge control agent is present in an amount of from about 0.01 to about 15 percent by weight of the total weight of the toner particle.
5. The toner of claim 1 having a triboelectric charge of from about −5 to about −60 uC/gm in A zone.
6. The toner of claim 1 , wherein the bulk level of the charge control agent is increased from about 5 to about 30 percent as compared to a bulk level of a toner particle prepared with the shell.
7. The toner of claim 1 , wherein the surface level of the charge control agent is increased from about 0.1 to about 15 percent as compared to a surface level of a toner particle prepared with the shell.
8. The toner of claim 1 , wherein the toner particles further comprise one or more surface additives.
9. The toner of claim 1 , wherein the toner particles have an average particle size of from about 4.5 to about 7.5 um.
10. A toner comprising
shell-less toner particles comprising
a core portion comprising a resin, wax and colorant,
a charge control agent distributed homogenously throughout the core portion, and
a residual surfactant on a surface of the core portion, wherein an amount of surfactant present in the toner particle is from about 20 to about 2500 ppm of the toner particle.
11. The toner of claim 10 , wherein the amount of surfactant present in the toner particle is reduced as compared to an amount of surfactant present in a toner particle prepared with the shell.
12. The toner of claim 10 , wherein amount of surfactant present in the toner particle is decreased from about 80 percent to about 30 percent as compared to an amount of surfactant present in a toner particle prepared with the shell.
13. A process for producing toner comprising:
adding and mixing a colorant, a wax, and a charge control agent to an emulsion comprising at least one resin to form toner particles;
aggregating the particles to form aggregated particles; and
coalescing the aggregated particles to form shell-less toner particles comprising
a core portion comprising a resin, wax and colorant, and
a charge control agent distributed homogeneously throughout the core portion, wherein a bulk level of the charge control agent in the core portion is from about 0.1 to about 50 percent by weight of the total weight of the toner particle and a surface level of the charge control agent on the core portion is from about 0.01 to about 10 percent by weight of the total weight of the toner particle.
14. The process of claim 13 further comprising washing the shell-less toner particles.
15. The process of claim 13 , wherein toner is an emulsion aggregation toner.
16. The process of claim 13 , wherein the charge control agent is selected from the group consisting of a zinc complex of 3,5-di-tert-butylsalicylic acid in powder form, a mixture of hydroxyaluminium-bis[2-hydroxy-3,5-di-tert-butylbenzoate] and 3,5-di-tert-butylsalicylic acid, a calcium complex of 3,5-di-tert-butylsalicylic acid, a zirconium complex of 3,5-di-tert-butylsalicylic acid, an aluminum complex of 3,5-di-tert-butylsalicylic acid, mixtures thereof.
17. The process of claim 13 , wherein the toner has a triboelectric charge of from about −5 to about −60 uC/gm.