Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Post imaging process – finishing – or perfecting composition...
Reexamination Certificate
2000-09-27
2002-03-26
Goodrow, John (Department: 1753)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Post imaging process, finishing, or perfecting composition...
C430S109400
Reexamination Certificate
active
06361914
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a resin binder composition for a non-contact fixing process used for developing electrostatic latent images formed in electrophotography, electrostatic recording method, electrostatic printing, and the like, a toner for a non-contact fixing process comprising the resin binder composition, a developer comprising the toner for a non-contact fixing process, and a method for fixing the toner in a non-contact fixing process.
2. Discussion of the Related Art
A non-contact fixing process includes a process in which light or heat energy is applied to a toner in a non-contacting state, thereby fixing the toner, such as a flash fixing or radiant (oven) fixing process, which has a feature in that the offset phenomenon and the deterioration of resolution, which are often found in contact-fixing, are not found. However, when the light or heat energy is deficient during fixing, the toner cannot be sufficiently melted, so that satisfactory fixing ability cannot be obtained. On the other hand, when the light or heat energy is too intensive, the viscosity of the toner drastically is lowered. When the surface tension acting on the toner exceeds the viscosity, the aggregation and migration of the toner at printed portion take place, so that there is generated a so-called “voids,” which are white voids phenomenon on a fixed image, whereby the photographic density of the image is lowered. Therefore, toners using a specific resin binder are disclosed in Japanese Patent Laid-Open Nos. Hei 8-87130, Hei 5-107805, and the like, in view of eliminating these defects found in the non-contacting fixing process. However, further improvements in the environmental resistance and the storage ability are desired, even though the fixing ability and the void resistance are somewhat improved.
An object of the present invention is to provide a resin binder composition for a non-contact fixing process which effectively prevents the generation of voids in the non-contacting fixing process and is excellent in the environmental resistance and the storage ability as well as in the fixing ability.
Another object of the present invention is to provide a toner for a non-contacting fixing process comprising the resin binder composition, and a developer comprising the toner for a non-contacting fixing process.
Still another object of the present invention is to provide a method for fixing the toner in a non-contact fixing process.
These objects and other objects of the present invention will be apparent from the following description.
SUMMARY OF THE INVENTION
The present invention pertains to the following:
[1] a resin binder composition for a non-contact fixing process comprising two or more polyesters having different softening points, wherein each of the polyesters is a resin obtained from an alcohol component consisting essentially of a compound represented by the formula (I):
wherein R 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, and wherein at least a polyester having the highest softening point is a cross-linked polyester;
[2] a toner for a non-contact fixing process comprising the resin binder composition as defined above;
[3] a developer comprising the toner as defined above; and
[4] a method for fixing a toner in a non-contact fixing process, comprising applying the toner to a fixing device, wherein the toner comprises the resin binder composition defined above.
DETAILED DESCRIPTION OF THE INVENTION
The resin binder composition for a non-contact fixing process of the present invention comprises two or more polyesters having different softening points. Since the polyesters having different softening points are contained as mentioned above, the molecular weight distribution of the resin binder composition becomes wider, so that the generation of voids found generally in the non-contacting process can be effectively prevented, whereby the fixing ability can be improved. The resin binder composition of the present invention can be especially preferably used as a resin binder composition for flash fixing process among the non-contact fixing processes such as flash fixing or radiant (oven) fixing processes, from the viewpoint of energy efficiency.
A further great feature of the present invention resides in that all of the polyesters are obtained from an alcohol component consisting essentially of a compound represented by the formula (I):
wherein R 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. Since the compound represented by the formula (I) is used as an alcohol component, a resin having low water-adsorbency is obtained, so that the environmental resistance of the resin is markedly improved. Also, since an aliphatic alcohol is not essentially used, the storage ability is improved. Here, the phrase “consisting essentially of a compound represented by the formula (I)” means that other compounds may be slightly contained in an amount so as not to hinder the object of the present invention.
Therefore, the polyester usable in the present invention, as mentioned above, is obtained by polycondensation of an alcohol component consisting essentially of a compound represented by the formula (I) with a carboxylic acid component. As the carboxylic acid component, dicarboxylic acid compounds may be used for the linear polyesters, and tricarboxylic or higher polycarboxylic acid compounds as well as the dicarboxylic acid compounds may be used for cross-linked polyesters.
The compound represented by the formula (I) includes bisphenol A of an alkylene oxide adduct, each of which has average moles added of 1 to 16, preferably 1.5 to 5.0, such as polyoxypropylene(2.2)-2,2-bis(4-hydroxyphenyl)propane and polyoxyethylene(2.2)-2,2-bis(4-hydroxyphenyl)propane. These compounds may be used alone or in admixture of two or more kinds.
The dicarboxylic acid compound includes phthalic acid compounds such as phthalic acid, isophthalic acid, and terephthalic acid; fumaric acid; maleic acid; adipic acid; and succinic acid compounds, which may be substituted by an aliphatic hydrocarbon group having 4 to 20 carbon atoms, such as dodecenylsuccinic acid or octylsuccinic acid, preferably substituted by an alkenyl group, acid anhydrides thereof, alkyl (1 to 8 carbon atoms) esters thereof, and the like. Among them, the phthalic acid compounds, the succinic acid compounds, acid anhydrides thereof and alkyl esters thereof are preferable.
The tricarboxylic or higher polycarboxylic acid compound includes trimellitic acid, pyromellitic acid, acid anhydrides thereof, alkyl(1 to 8 carbon atoms) esters thereof, and the like.
In the cross-linked polyester, the tricarboxylic or higher polycarboxylic acid compound is contained in an amount of preferably from 3 to 40% by mol, more preferably from 5 to 25% 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.
In the present invention, it is preferable that two or more of the polyesters having different softening points comprise at least one polyester having a softening point of 80° C. or more and less than 120° C. (low-softening point polyester), and at least one polyester having a softening point of 120° C. or more and 160° C. or less (high-softening point polyester).
It is desired that the softening point of the low-softening point polyester is 80° C. or more and less than 120° C., preferably 90° C. or more and 110° C. or less, and that the softening point of the high-softening point polyester is 120° C. or more and 160° C. or less, preferably 130° C. or more and 153° C. or less, from the viewpoints of the fixing ability and the storage ability. In addition, the glass transi
Semura Tetsuhiro
Ueno Yoshihiro
Goodrow John
Kao Corporation
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