Toner and process of preparing the same
View Patent ↗A toner includes a core containing a binder resin, wax, and a colorant, and an external additive layer coating the core, wherein the core is prepared such that it is extruded and extended to have a fiber phase, and is pulverized. The toner has an improved fixing ability to allow an electrostatic image to be fixed at a low temperature while having an excellent durability and an improved storage stability, while exhibiting reduced toner blocking and offset phenomena.
1. A toner comprising:
a core which contains a binder resin, wax, and a colorant, the core having a fibril-structure and an aspect ratio in which a ratio of a major axis length of a section of the core to a minor axis length of a section of the core ranges from about 40 to about 70; and
an external additive layer to coat the core.
2. The toner of claim 1 , wherein the core includes a diameter in a range of about 4 to about 20 μm.
3. The toner of claim 1 , wherein the core contains 1 to 20 parts by weight of wax, and 0.6 to 6 parts by weight of a colorant, based on 100 parts by weight of the binder resin.
4. The toner of claim 1 , wherein the binder resin is polyester based resin or polystyrene-acryl based resin.
5. The toner of claim 1 , wherein the binder resin includes a number average molecular weight in a range of 1,000 to 120,000 and a softening point in a range of about 90 to about 170° C.
6. The toner of claim 1 , wherein the wax is shaped of a fibril.
7. The toner of claim 1 , wherein the melting point of the wax is in a range of about 50 to about 150° C.
8. The toner of claim 1 , wherein the colorant is selected from the group consisting of carbon black, aniline black, yellow, magenta, cyan colorants, and combinations thereof.
9. The toner of claim 1 , wherein the external additive layer includes silica, metallic oxide, and polymer beads.
10. The toner of claim 1 , wherein the external additive contains 0.1 to 10 parts by weight of silica, 0.01 to 1 parts by weight of metallic oxide and 0.1 to 10 parts by weight of polymer beads, based on 100 parts by weight of the total content of the binder resin.
11. The toner of claim 9 , wherein the silica includes macroparticles having a volume-average particle diameter of 30 to 200 nm and microparticles having a volume-average particle diameter of 5 to 20 nm.
12. The toner of claim 9 , wherein the metallic oxide is titanium oxide (TiO 2 ).
13. The toner of claim 9 , wherein the polymer beads include at least one selected from the group consisting of spherical styrene resin, spherical methyl methacrylate resin, spherical styrene-methyl methacrylate copolymer, spherical acrylic resin, and spherical styrene-acrylic copolymer.
14. The toner of claim 1 , wherein the toner has a volume-average particle diameter in a range of about 3 to about 10 μm.
15. An image forming apparatus, comprising:
an organic photoreceptor;
a means for charging a surface of the organic photoreceptor;
a means for forming an electrostatic latent image on the surface of the organic photoreceptor;
a means for receiving a toner, the toner comprising:
a core containing a binder resin, wax, and a colorant, the core having a fibril-structure and an aspect ratio in which a ratio of a major axis length of a section of the core to a minor axis length of a section of the core ranges from about 40 to about 70; and
an external additive layer coating the core;
a means for forming a toner image by supplying the toner to develop the electrostatic latent image of the organic photoreceptor; and
a means for transferring the toned image from the photoreceptor to a transferring member.
16. A toner usable with an image forming apparatus, comprising:
a core containing a colorant and having a fibril-structure and an aspect ratio in which a ratio of a major axis length of a section of the core to a minor axis length of a section of the core ranges from about 40 to about 70; and
an external additive layer to coat the fibril-shaped core.
17. The toner of claim 16 , wherein the core includes a diameter in a range of about 4 to about 20 μm.
18. The toner of claim 16 , wherein the core further includes a resin and a wax.