Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Post imaging process – finishing – or perfecting composition...
Reexamination Certificate
2000-08-25
2002-02-26
Rodee, Christopher (Department: 1753)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Post imaging process, finishing, or perfecting composition...
C430S108300, C430S108700
Reexamination Certificate
active
06350551
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a yellow toner used for development of electrostatic images formed in electrophotography, electrostatic recording, electrostatic printing, or the like.
2. Discussion of the Related Art
As a yellow toner, a toner containing a dichlorobenzidine pigment such as Pigment Yellow 17 as a colorant has been used. However, in the toner, the changes in hue by continuous printing are large depending upon the kinds of the charge control agent contained. Moreover, since dichlorobenzidine is listed as one of the environmental label Blue Angel regulation in Eco-marks in Germany, there has been expected a development of a yellow toner using a colorant without containing the dichlorobenzidine pigment.
Therefore, there has been reported a toner containing Pigment Yellow 185 excellent in the heat resistance in Japanese Patent Laid-Open No. Hei 6-118715. However, in order to obtain a more excellent toner for practical purposes, the toner is required to satisfy various properties such as environmental stability or color reproducibility, fixing ability, and changes in hues.
An object of the present invention is to provide a yellow toner having excellent environmental stability, color reproducibility, and fixing ability, and being less likely to undergo changes in hue, even when subjected to continuous printing.
The above and other objects of the present invention will be apparent from the following description.
SUMMARY OF THE INVENTION
The present invention relates to a yellow toner comprising fine resin particles and an external additive being added to surfaces of the fine resin particles, wherein the fine resin particles comprise:
(a) a resin binder comprising a polyester obtained by polycondensing an alcohol component comprising a compound represented by the formula (I):
wherein R
1
is an alkylene group having 2 or 3 carbon atoms; each of x and y is a positive number, wherein a sum of x and y is 1 to 16, with a carboxylic acid component comprising a dicarboxylic acid compound and a tricarboxylic or higher polycarboxylic acid compound;
(b) a colorant comprising a compound represented by the formula (II):
(c) a charge control agent comprising a compound selected from the group consisting of metal compounds of a salicylic acid derivative represented by the formula (III):
wherein each of R
2
, R
3
, and R
4
is independently hydrogen atom, a linear or branched alkyl group having 1 to 10 carbon atoms, or allyl group; M is zinc, zirconium, chromium, aluminum, copper, nickel, or cobalt; m is an integer of 2 or more; and n is an integer of 1 or more; and metal compounds of a benzilic acid derivative represented by the formula (IV):
wherein Q is boron or aluminum; m is an integer of 2 or more; and n is an integer of 1 or more; and
wherein the external additive comprises silica having an average particle size of from 35 to 350 nm.
DETAILED DESCRIPTION OF THE INVENTION
The resin binder in the present invention comprises a polyester obtained by polycondensing an alcohol component comprising a compound represented by the formula (I):
wherein R
1
is an alkylene group having 2 or 3 carbon atoms; each of x and y is a positive number, wherein a sum of x and y is 1 to 16, preferably 1.5 to 5.0, with a carboxylic acid component comprising a dicarboxylic acid compound and a tricarboxylic or higher polycarboxylic acid compound.
The compound represented by the formula (I) includes alkylene(2 to 3 carbon atoms) oxide(average moles added 1 to 16) adduct of bisphenol A such as polyoxypropylene(2.2)-2,2-bis(4-hydroxyphenyl)propane and polyoxyethylene(2.0)-2,2-bis(4-hydroxyphenyl)propane. In addition, other alcohol components include ethylene glycol, propylene glycol, glycerol, pentaerythritol, trimethylolpropane, hydrogenated bisphenol A, sorbitol, or alkylene oxide(average moles added 1 to 16) adducts thereof, of which alkylene moiety has 2 to 4 carbon atoms. These compounds may be used alone or in admixture of two or more kinds.
It is desired that the compound represented by the formula (I) is contained in an amount of 5% by mol or more, preferably 50% by mol or more, more preferably 100% by mol or more, of the alcohol component.
The dicarboxylic acid compound includes dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, fumaric acid, and maleic acid; succinic acids substituted by an alkyl group having 1 to 20 carbon atoms or by an alkenyl group having 2 to 20 carbon atoms, such as dodecenylsuccinic acid and octylsuccinic acid; acid anhydrides thereof, alkyl(1 to 8 carbon atoms) esters of these acids, and the like.
The tricarboxylic or higher polycarboxylic acid compound includes trimellitic acid, pyromellitic acid, acid anhydrides thereof, alkyl(1 to 8 carbon atoms) esters of these acids, and the like.
The dicarboxylic acid compound is contained in an amount of preferably from 70 to 99.95% by mol, more preferably from 70 to 90% by mol, of the carboxylic acid component. In addition, the tricarboxylic or higher polycarboxylic acid compound is contained in an amount of preferably from 0.05 to 30% by mol, more preferably from 10 to 30% by mol, of the carboxylic acid component.
The polycondensation of the alcohol component with the carboxylic acid component is carried out, for instance, by the reaction at a temperature of from 180° to 250° C. in an inert gas atmosphere, using an esterification catalyst as occasion demands.
It is preferable that the polyester has an acid value of from 0.1 to 55 mg KOH/g, a hydroxyl value of from 15 to 50 mg KOH/g, a softening point of from 90° to 140° C., and a glass transition temperature of 50° to 70° C., respectively.
In the present invention, the resin binder may comprise a linear polyester obtained without using a tricarboxylic or higher polycarboxylic acid compound. It is desired that such a linear polyester is used so that the polyester obtained from the above tricarboxylic or higher polycarboxylic acid compound is contained in an amount of 30% by weight or more, preferably 50% by weight or more, more preferably 100% by weight, of the resin binder.
The colorant in the present invention comprises a compound represented by the formula (II):
As the colorant, there can be used commercially available products such as “Paliotol Yellow D1155” (commercially available from BASF).
The compound represented by the formula (II) is contained in an amount of preferably from 1 to 25 parts by weight, more preferably from 2.5 to 5.0 parts by weight, based on 100 parts by weight of the resin binder.
The charge control agent in the present invention comprises a compound selected from the group consisting of metal compounds of a salicylic acid derivative represented by the formula (III):
wherein each of R
2
, R
3
, and R
4
is independently hydrogen atom, a linear or branched alkyl group having 1 to 10 carbon atoms, or allyl group; M is zinc, zirconium, chromium, aluminum, copper, nickel, or cobalt; m is an integer of 2 or more; and n is an integer of 1 or more; and
metal compounds of a benzilic acid derivative represented by the formula (IV):
wherein Q is boron or aluminum; m is an integer of 2 or more; and n is an integer of 1 or more.
Here, the metal compound may be either a metal salt or a metal complex. By the use of the metal compound of the formula (III), the resulting yellow toner is imparted with remarkably excellent environmental stability, and by the use of the metal compound of the formula (IV), the resulting yellow toner is imparted with remarkably excellent color reproducibility.
In the formula (III), R
3
is preferably hydrogen atom, and each of R
2
and R
4
is preferably a branched alkyl group having 3 to 10 carbon atoms, more preferably tert-butyl group.
Among zinc, zirconium, chromium, aluminum, copper, nickel, and cobalt which are represented by M, zinc, zirconium and chromium which have an excellent effect of imparting chargeability are preferable, and zinc and zirconium are more preferable.
Commercially available products which are suitably used in the present i
Sata Shin-ichi
Shirai Eiji
Birch & Stewart Kolasch & Birch, LLP
Kao Corporation
Rodee Christopher
LandOfFree
Yellow toner does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Yellow toner, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Yellow toner will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2954955