JPH0456868A - Toner - Google Patents

Abstract

PURPOSE:To contrive the improvements in a void resistance characteristic and a fixing property by using an epoxy resin being a monomer consisting of a metal phenoxyd resin as an alcoholic component of a binder resin. CONSTITUTION:The epoxy resin in which the monomer is the metal phenoxyd as an alcoholic component constituting the epoxy resin in the toner using an epoxy resin, is used as the binder resin. As the used metal phenoxyds, the phenoxids of Al, Mg, Sn, Be, Ca, Fe, Co, Cu, Zn, Sb, etc., are exemplified. By using the metal phenoxyd in such a manner, even in the case that an oligomer which deposits as a metal oxide at the resin manufacturing stage and has an improved fixing property is used, the melt viscosity of the toner at a fixation time is kept higher and the void phenomenon is prevented.

Description

[Detailed Description of the Invention] [Summary] Regarding a toner for flash fixing used for developing electrostatic latent images such as in electrophotography, this toner has excellent void resistance and
In order to provide a toner with high fixing properties, the toner uses an epoxy resin as a binder resin, and an epoxy resin containing a metal phenoxide as a monomer is used as an alcohol component constituting the epoxy resin.

[Industrial Application Field] The present invention relates to a toner for flash fixing used to provide electrostatic latent images in electrophotography and the like.

As an electrophotographic method, the method described in U.S. Pat. A similar electrostatic charge is formed on the body, and then the latent image is developed and visualized using fine powder called toner, and if necessary, the toner image is fixed on paper or the like to obtain a copy.

[Prior Art] Toners for developing these electrostatic latent images have conventionally been prepared by dispersing a colorant such as carphone black in a binder resin made of natural or synthetic polymer.
Particles pulverized to about 20 μm are used. Such toner is usually used alone or mixed with a carrier material such as iron powder or glass to develop an electrostatic latent image.

When the toner is used alone (-component development method), the toner usually contains magnetic powder, and the toner becomes triboelectrically charged when it rubs against members such as the wall of the developing device and the magnet roll in the developing device. Furthermore, the toner is held on the magnet roll by the magnetic force of the magnet roll, and as the magnet roll rotates, the toner is carried to the latent image area on the photoconductive insulator, and the charged toner is transferred to the latent image by the electrical attraction force. Development is performed by adhesion.

In addition, when using a mixture of carrier and toner (two-component development method) 1, the toner is carried on the carrier to the latent image area on the photoconductive insulator, and only the charged toner is electrically attracted. Development is achieved by selective attachment by force. In this case as well, the toner image is formed using only toner.

In the case of a two-component development method, iron powder or other ferromagnetic particles are usually used as the carrier, and in this case,
The magnetic particles are held by a magnet roll in the developer device to form a magnetic brush, and as the magnet roll rotates, the magnetic particles are carried by the magnetic brush to the latent image area on the photoconductive insulator. Toner is transported.

On the other hand, as a binder resin used in toner, a low polymer polymer generally called an oligomer is often used. Oligomers have low molecular weight, so their melt viscosity is low;
Because of its good thermal stability, it is widely used as a binder resin for electrophotographic toners.

Further, the fixing is to melt the powder image of the toner and fix it to the recording paper, and the various methods described above are available for this purpose. Among these methods, flash fixing, which is a typical optical fixing method, is a method in which fixing is performed by flashing light from a discharge tube such as a xenon flash lamp, and has the following major characteristics.

■Since it is non-contact, it does not degrade image resolution during development.

■There is no waiting time after the power is turned on, and a quick start is possible.

■Even if the recording paper gets stuck in the fuser due to system failure, it will not ignite.

■Fixing is possible regardless of the material or thickness of the recording paper, such as glued paper, preprinted paper, or paper of different thickness.

The process by which toner adheres to recording paper by flash fixing is as follows.

As described above, when a toner image is transferred to recording paper, it adheres to the recording paper as a powder to form an image, and if rubbed with a finger, for example, the image will collapse. When the toner is irradiated with a flash of light from a discharge tube such as a xenon flash lamp, the toner absorbs the energy of the flash, its temperature rises, it softens and melts, and adheres to the recording paper. After the flash ends, the temperature drops and the image solidifies to become a fixed image, completing the fixing process.The fixed image fixed on the recording paper will not disintegrate even if it is rubbed with a finger, for example.

What is important in flash fixing is that the toner firmly adheres to the molten recording paper, and for this purpose, the toner emits light energy in the flash, including the thermal energy that is dissipated into the outside world and does not contribute to the temperature rise. It must be absorbed and sufficiently melted. Therefore, if the applied light energy is insufficient, the toner cannot be sufficiently melted and satisfactory fixing performance cannot be obtained. On the other hand, if the light energy is too strong, as shown in FIG. 1, explosive fixation of toner 1 causes white spots called voids 5 to occur in the image, resulting in a decrease in image density. Therefore, the toner 1 for flash fixing needs to exhibit good fixing properties in a light energy range where voids 5 are not generated due to explosive fixing. In FIG. 1, 2 represents a recording paper, 3 represents a flash of light, and 4 represents a fixed image, respectively.

Conventionally, epoxy resins such as bisphenol A diglycidyl ether polymer and polyester resins such as polyethylene terephthalate have been commonly used as binder resins for electrophotographic toners.

[Problems to be Solved by the Invention] However, in such conventional toners, when epoxy resin or polyester resin is used as the binder resin, in order to obtain good fixing properties, it is necessary to use low molecular weight Since it is necessary to use an oligomer with a melting point, the melt viscosity is low, and when the toner is melted by flash light irradiation, the toner aggregates and fuses to solidify, making it impossible to avoid the generation of voids in the image. In order to prevent this, increasing the degree of polymerization of the resin and increasing its melt viscosity also raises the melting point, which in turn deteriorates the fixing properties and causes the problem that the toner is not sufficiently fused and solidified to the paper.

Another method of increasing the melt viscosity of the resin is to disperse an inorganic filler in the resin, but in this case, the powdery filler is added to the resin, so the dispersibility is poor, and the addition of the filler has no effect on the charging characteristics of the toner. It is not desirable because it appears strongly.

The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a toner having excellent void resistance and high fixability.

[Means for Solving the Problems] As a result of study, the inventors found that as a method of increasing only the melt viscosity of the binder resin while preventing the melting point of the binder resin from increasing, the alcohol component that forms the main chain structure of the binder resin was developed. By using a metal phenoxide as an essential component, it precipitates as a metal oxide during the resin synthesis stage, so even when using an oligomer that has a relatively small molecular weight and a low melting point and has good fixing properties, it is difficult to fix. The inventors have discovered that it is possible to maintain a high melt viscosity of the toner and to prevent the above-mentioned void phenomenon, and have accomplished the present invention.

That is, the present invention is a toner using an epoxy resin as a binder resin, in which an epoxy resin containing a metal phenoxide as a monomer is used as an alcohol component constituting the epoxy resin.

The present invention will be explained in detail below.

Examples of metal phenoxides used in the present invention include phenoxides of aluminum, magnesium, titanium, beryllium, calcium, iron, cobalt, copper, zinc, antimony, tin, nickel, manganese, and the like. Further, the amount of these metal phenoxides is determined based on the melting characteristics of the toner, but usually the metal content is 0.0% of the toner weight. If it is less than 5w1%, no effect of increasing the melt viscosity of the toner due to the formation of metal oxides can be expected.

On the other hand, if the metal content is 10% by weight or more of the toner weight, the melt viscosity at the time of toner cross-linking will increase extremely, resulting in poor toner productivity.

In addition, alcohol components constituting epoxy include novolacs such as phenol novolac and oxocresol novolac, bisphenol A, and bisphenol F.
Alcohols in which part or all of the hydrogen atoms in the hydroxyl groups are replaced with metals, such as bisphenols such as alcohols, can be used alone or in combination. When alcohols are used in combination, if one monomer is provided with a metal oxide in an amount greater than the required amount, the remaining monomer does not need to replace the hydrogens of the hydroxyl groups with metals.

The epoxy used in the present invention can be used alone as a toner binder, but it can also be used in combination with other binder resins. When using other binder resins in combination, any resin used in electrophotography may be used, such as styrene acrylic, epoxy, polyester, etc.

The toner used in the present invention can be manufactured by a conventionally known method. That is, binder resin, colorant, carbon, charge control agent, etc. are melt-kneaded and uniformly dispersed using, for example, a pressure kneader, roll mill, extruder, etc., and then, for example,
The desired toner can be obtained by pulverizing the toner using a jet mill or the like and classifying it using a classifier such as a wind classifier.

[Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

Example First, as the alcohol component of the binder resin, 50 mole parts of aluminum phenoxide, in which some of the hydrogens in the hydroxyl groups of bisphenol A are replaced with aluminum metal, and as the acid component, 30 mole parts of epichlorohydrin, so that the aluminum metal oxide content is 3 wt%. Epoxy resin b (epoxy equivalent: 900 to 1000) was obtained.

Next, using 92 parts by weight of the epoxy resin B, 5 parts by weight of carbon black (Black Pearls L: average particle size 0.024 μm 1 specific surface area 138 n (/g; manufactured by Capot Co., Ltd.) as a coloring agent, and metal-containing azo dye (Bontron) 5
-34. Orient chemical type) was added thereto, and melt-kneaded at 130° C. for 30 minutes using a pressure kneader to obtain a toner mass. The cooled toner mass was then processed into a coarse toner of about 2 mm using a Rotobrex mill.

Next, the coarse toner is finely pulverized using a jet mill (PJM pulverizer, manufactured by Nippon Pneumatic Industries), and the pulverized product is classified using an air classifier (manufactured by Alpine), and the particle size is 5 to 5.
A positively charged toner B of 20 μm was obtained.

85 parts by weight of toner, unshaped iron powder TSV1 as carrier
A developer consisting of 95 parts by weight of 00/200 (Japanese iron powder type) was prepared and a printing test was conducted using a modified FACOM-6715D printer. At this time, the thickness of the toner on the recording paper was set to 10 to 15 μm, and the occurrence of voids was visually determined.

As a result of printing evaluation, toner B did not generate any voids.

Comparative Example Epoxy resin C was obtained in the same manner as in Example 1, except that bisphenol A not substituted with AA was used as the alcohol component of the binder resin. Toner C was prototyped using epoxy resin C, and printing was evaluated.

As a result, a large number of voids were generated in Toner C.

5. Void.

Claims (1)

[Scope of Claims] A toner using an epoxy resin as a binder resin, characterized in that an epoxy resin containing a metal phenoxide as a monomer is used as an alcohol component constituting the epoxy resin.