Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Post imaging process – finishing – or perfecting composition...
Reexamination Certificate
2001-03-29
2003-06-03
Goodrow, John (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Post imaging process, finishing, or perfecting composition...
C430S111400, C428S400000
Reexamination Certificate
active
06573018
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the surface-treated metallic-oxide fine powder, which has good flow ability and excellent stability against agitation time, and especially relates to a surface-treated silica fine powder. More specifically, this invention relates to the surface-treated metallic-oxide fine powder which improves the stability against agitation time, its production method, and an electrophotographic toner using the same, regarding the surface-treated silica fine powder etc., which is added in a powder coating, an electrophotographic toner, etc., in order to improve the flow ability, to prevent aggregation or to adjust charge, etc.
2. Prior Art
The surface-treated metallic-oxide fine powder, in which the surface of metallic-oxide fine powder, such as silica, titania, and alumina, is treated with organic materials, is widely used as the flow ability improving agent of the electrophotographic toner for a copying machine, a laser beam printer, and a plain-paper facsimile. In such applications, the tribo-electro static charge to an iron powder and an iron oxide powder as a carrier is one of the important quality factors. Wherein, although the metallic-oxide powder which has negative charge in the tribo-electro static charge is general, the metallic-oxide powder which is controlled to positive charge is also known.
In the charge of the metallic-oxide fine powder, for example, a metallic-oxide powder having positive charge or zero charge, which is introduced with the amino group and the hydrophobic group, is disclosed in Japanese Patent Laid Open No.62-185405. In addition, a method is shown in Japanese Patent Laid Open No.63-52561 in which the silica synthesized by a vapor phase method is treated with a silane containing epoxy groups and subsequently with the amines. Moreover, the metallic-oxide powder, which was heated with the modified silicone oil containing epoxy groups, and treated with an organic compound containing amino group, is shown in Japanese Patent Laid Open No. 63-155155.
Problems to be Solved
However, while these conventional metallic-oxide powders, especially silica powder, can control early time tribo-electro static charge, the stability with time is inferior. That is, there is a problem that the charge varies much as agitation time becomes longer. As a method for solving this problem, addition of titanium oxide to the toner is proposed in Japanese Patent Laid Open No. 8-220791. Moreover, the method of adding alumina to the toner is proposed in Japanese Patent Laid Open No. 9-150382. However, compared with silica powder, titanium-oxide powder and alumina powder are inferior in the effectiveness for improving the toner flow ability.
The present invention solves the above-mentioned conventional problems, and provides the surface-treated metallic-oxide fine powder having excellent stability against agitation time as well as good flow ability. According to this invention, the metallic-oxide fine powder, especially silica fine powder, which has excellent stability against agitation time is obtained. For example, a surface-treated powder is obtained in which the difference between the amounts of charge for 1 minute and 5 minutes is less than 200 &mgr;C/g, or the ratio of said amounts is less than 2.5.
Means to Solve Problems
The surface-treated metallic-oxide fine powder of the present invention controls the charge of the metallic-oxide fine powder and improves the stability by suppressing the variation of the amount of charge with time by surface-treating with two silane coupling agents containing amino group, one of which is for controlling the charge and the other is for increasing the charge stability, and the hydrophobic agent and introducing plural kinds of amino groups and hydrophobic groups to the surface of the metallic-oxide fine powder.
That is, this invention relates to the surface-treated metallic-oxide fine powder which comprises the following formulations and its production method or use.
1. A surface-treated metallic-oxide fine powder satisfying at least one of the relational expressions of the following formula 1 or 2, in which the amount of tribo-electro static charge to iron powders is shown:
|Q1−Q5|<200 &mgr;C/g (formula 1)
Q1/Q5<2.5 (formula 2)
wherein Q1 is the amount of tribo-electro static charge at 1 minute after the agitation of the iron powder and the metallicoxide fine powders, and Q5 is the amount of tribo-electro static charge at 5 minutes after.
2. A hydrophobic surface-treated metallic-oxide fine powder, wherein the tribo-electro static charge is stabilized by surface-treating of the metallic-oxide fine powder, using the silane coupling agent containing primary amino group shown by the following formula 3, and at least one of silane coupling agent containing amino group chosen from silane coupling agents containing amino group shown by the following formula 4, and the hydrophobic agent
XnR
(3-n)
Si—(CH
2
)
m
—NH
2
(formula 3)
wherein X is the functional group which can be hydrolyzed, R is the hydrogen group or the alkyl group, n is an integer from 1 to 3, m is an integer from 1 to 6.
XnR
(a-n)
Si—(CH
2
)
m
−NR1R2 (formula 4)
wherein X and R are the same as above mentioned ones, R1 and R2 are hydrogen groups, alkyl groups, or aryl groups, and the part of said groups can be replaced by oxygen, nitrogen, or sulfur atom except the case of R1═R2═H, n is an integer from 1 to 3 and m is an integer from 1 to 6.
3. A surface-treated metallic-oxide fine powder according to above 1, which has the tribo-electro static charge satisfying at least one of the relational expressions shown in above-mentioned formula 1 and 2, by surface-treating the metallic-oxide fine powder using the silane coupling agent containing primary amino group shown by above-mentioned formula 3, at least one of silane coupling agent containing amino group chosen from the silane coupling agent containing amino groups shown by above-mentioned formula 4, and the hydrophobic agent.
4. A surface-treated metallic-oxide fine powder according to above 2, wherein the addition of the silane coupling agent containing primary amino group of group of above-mentioned formula 3, is 0.1-20% by weight, and the addition of the silane coupling agent containing the amino group of above-mentioned formula 4, is 0.1-20% by weight, and the addition of the hydrophobic agent is 5-50% by weight.
5. A surface-treated metallic-oxide fine powder according to above 2, 3 or 4, wherein the hydrophobic agent is an alkyl silazane compound, an alkylalkoxy-silane compound, a chloro-silane compound, a silicone varnish containing reactive functional groups, a non-reactive silicone varnish, a silicone oil containing reactive functional groups, or a non-reactive silicone oil, and the degree of hydrophobicity by the permeability method is 70% or more.
6. A surface-treated metallic-oxide fine powder according to above 1 or 2, wherein said metallic-oxide fine powder is the silica fine powder which generated by the flame hydrolysis of a volatile silicon compound having BET specific surface area less than 400 m
2
/g.
7. A production method of the surface-treated metallic-oxide fine powder, wherein the silane coupling agent containing primary amino group shown by above-mentioned formula 3, the silane coupling agent containing amino group shown by above-mentioned formula 4, and the hydrophobic agent, are sprayed to the metallic-oxide fine powder to be heated, or said metallic-oxide fine powder is heated after dipped in the mixed solutions of these agents.
8. A toner containing the surface-treated silica fine powder according to above 1, 2 or 3.
Embodiment of the Invention
Hereafter, this invention is concretely explained based on examples.
As the surface-treated metallic-oxide fine powder of the present invention, especially as the silica fine powder, so-called humed silica can be used efficiently, which has the specific surface area (by nitrogen adsorption-process or BET process
Brandes Ralph M.
Ishibashi Naruyasu
Komai Eiji
Goodrow John
LaPointe Dennis G.
Marson Law, P.A.
Nippon Aerosil Co., Ltd.
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