Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Process of making developer composition
Reexamination Certificate
2001-07-24
2003-09-09
Goodrow, John (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Process of making developer composition
C430S137140
Reexamination Certificate
active
06617091
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a toner and a production method thereof.
BACKGROUND OF THE INVENTION
Currently, a technology for synthesizing a developer for an electrostatic image by a polymerization process has been known. However, the toner particle synthesized by a suspension polymerization method has a shortcoming that such the particle is inferior in the cleaning ability since it has a spherical shape.
Consequently, a method to produce an irregular-shaped toner particle by association of a resin particle obtained by a suspension polymerization process together with a colorant particle is described in Japanese Patent Publication Open to Public Inspection No. 63-186253.
SUMMARY OF THE INVENTION
However, a colorant is exposed at the surface of the toner particle obtained by the above-mentioned method. The charging property and the developing ability of such the toner are varied, for example, when the toner is used for a long period of time under a high humid condition.
The variation of the charging property and the developing ability of the toner causes a variation or lowering of the image density or fogging, and changing of the color of a color image.
The first object of the invention is to provide a polymer toner in which the amount of the colorant existing at the surface of the toner particle is small.
The second object of the invention is to provide a polymer toner which does not cause variation of image density or occurrence of fogging caused by the change of charging property and the developing ability even when the toner is used to image formation for a long period of time.
The third object of the invention is to provide a polymer toner which does not cause variation of color of image caused by the change of the charging property and the developing ability even when the toner is used to color image formation for a long period of time.
The fourth object of the invention is to provide a method for suitably producing the excellent polymer toner as above-mentioned.
The fifth object of the invention is to provide a method for forming an image using the excellent polymer toner as above-mentioned.
1. A method of preparing toner comprising process for adhering by fusing resin particles onto surface of colored particles (core particles) containing a resin particle and a colorant by salting-out/fusion-adhering to form the resin layer (shell).
2. The method of item 1, wherein the colored particles (core particles) are formed by salting-out/fusion-adhering the resin particle (A) and the colorant particle.
3. The method of item 2, wherein process for forming the colored particles (core particles) and a process of forming the resin layer (shell) on the colored particle are continuously performed.
4. The method of item 1, wherein the colored particles (core particles) have an average spherical coefficient of from 0.850 to 0.950.
5. The method of item 1, wherein weight average molecular weight of the resin particle A (MwA) is from 15,000 to 500,000, and the weight average molecular weight of the resin particle A and weight average molecular weight of the resin particle B (MwB) satisfy relation:
0.1≦(
MwA/MwB
)≦20.0.
6. The method of item 2, wherein the resin particle B comprises a low molecular weight resin having a weight average molecular weight of from 5,000 to 20,000.
7. The method of item 2, wherein at least one of the resin particle (A) and the resin particle (B) are formed by a multistep polymerization method.
8. The method of item 7, wherein the resin particle B comprises a low molecular weight resin having a weight average molecular weight of from 5,000 to 20,000 in an amount of not less than 50% byweight.
9. The method of item 2, wherein the colored particles (core particles) are formed by salting-out/fusion-adhering the resin particle A and the colorant particle in an aqueous medium.
10. The method of item 2, wherein the colored particles (core particles) are formed by salting-out/fusion-adhering the resin particle A and the colorant particle at temperature of from Tg+10° C. to Tg+50° C.
11. The method of item 2, wherein the toner is formed by salting-out/fusion-adhering the resin particles B on the colored particles (core particles) at temperature of from Tg+10° C. to Tg+50° C.
12. The method of item 2, wherein the colored particles are formed by salting-out/fusion-adhering a resin particle A having high molecular weight, a resin particle A having middle molecular weight, a resin particle A having low molecular weight and the colorant particle.
13. The method of item 2, wherein Tg of the resin particle A is from 45 to 70° C., and Tg of the resin particle B is from 100 to 140° C.
14. The method of item 2, wherein an interval between time of addition of a salting-out agent to suspension in which the resin particle A and the colorant particle are dispersed, and time at which a temperature of suspension is reached to a temperature high than glass transition temperature Tg, a temperature at which the adherence become possible, is not more than 120 minutes.
15. The method of item 1, wherein weight average molecular weight of the resin particle A (MwA) is from 15,000 to 500,000, and the weight average molecular weight of the resin particle A and weight average molecular weight of the resin particle B (MwB) satisfy relation:
0.1≦(
MwA/MwB
)≦20.0.
16. The method of item 15, wherein the colored particles (core particles) are formed by salting-out/fusion-adhering the resin particle A and the colorant particle at temperature of from Tg+10° C. to Tg+50° C., and the toner is formed by salting-out/fusion-adhering the resin particles B on the colored particles (core particles) at temperature of from Tg +10° C. to Tg+50° C.
17. The method of item 16, wherein Tg of the resin particle A is from 45 to 70° C., and Tg of the resin particle B is from 100 to 140° C.
18. The method of item 17, wherein an interval between time of addition of a salting-out agent to suspension in which the resin particle A and the colorant particle are dispersed, and time at which a temperature of suspension is reached to a temperature high than glass transition temperature Tg, a temperature at which the adherence become possible, is not more than 120 minutes.
19. The method of item 15, wherein the resin particle B comprises a low molecular weight resin having a weight average molecular weight of from 5,000 to 20,000.
20. The method of item 15, wherein at least one of the resin particle (A) and the resin particle (B) are formed by a multistep polymerization method.
The embodiments of the invention are described.
The toner according to the invention is a toner constituted by a toner particle comprising a colored particle (core particle) containing a resin and a colorant and a resin layer (shell) adhered by fusion on the surface of the core colored particle by a salting-out/fusion-adhering method.
The toner according to the invention is a toner comprising a colored particle (core particle) obtained by salting out/fusion-adhering a resin particle A and a colorant particle, and a resin layer (shell) formed by adhering a resin particle B on the surface of the colored core particle by the salting-out/fusion-adhering method.
In the toner according to the invention, it is preferable that the weight average molecular weight of the resin particle A (MwA) is within the range of from 15,000 to 500,000, and the weight average molecular weight of the resin particle A and the weight average molecular weight of the resin particle B (MwB) satisfies the following relation.
0.1≦(
MwA/MwB
)≦20.0
In the toner according to the invention it is preferable that a low molecular weight resin having a weight average molecular weight of from 5,000 to 20,000 is contained in the fine resin particle B.
In the toner according to the invention, it is preferable that at least on of the resin particle A and the resin particle B is a combined resin particle produced by a multistep polymerization.
The production method according to the invention contains the process for adhe
Kohno Shigenori
Nishimori Yoshiki
Shirose Meizo
Yamada Hiroyuki
Yamanouchi Takao
Goodrow John
Konica Corporation
Muserlian Lucas and Mercanti
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