JPH03180854A - Flash fixing toner and manufacture of same - Google Patents

Abstract

PURPOSE:To prevent dropout of a toner image due to void by using a specified polyester as a binder. CONSTITUTION:This toner contains as the alcoholic component for composing the binder polyester one of a metal alkoxide, such as AlOCH2CH2OAl, and a metal phenoxide as an essential component. As the acid component, terephthalic acid and the like can be used. It is preferred to add at least a colorant and an electric charge controller to this binder, to melt and knead it to form toner blocks, to pulverize and classify them, and thus to manufacture the flash fixing toner.

Description

[Detailed Description of the Invention] [Summary] The purpose of this invention is to commercialize a toner for flash fixing that has excellent void resistance and excellent fixing properties. Alternatively, a polyester resin containing either metal phenoxide as an essential monomer is used as a binder, at least a coloring agent and a charge control agent are added to the binder, melt-kneaded to form a toner mass, and the toner mass is crushed and classified. A method for producing a toner for flash fixing is characterized by:

[Industrial application field]

The present invention relates to a flash fixing toner having excellent void resistance and fixing properties, and a method for producing the same.

Electrophotographic technology is widely used in copying machines, but is also actively used in information devices such as printers and facsimile machines.

As an electrophotographic method, the method described in US Pat. No. 2,297,691 is well known.

That is, a uniform electrostatic charge is applied to a photoconductive insulator such as a photocondrum by corona discharge, and an electrostatic latent image is formed by irradiating a light image by various means.
Next, this latent image is developed and visualized using a colored fine powder called toner, and if necessary, the toner image is transferred to paper etc., and then fixed by applying pressure, heat, light, etc. to obtain printed matter. It is.

[Conventional technology]

The toner used to develop the electrostatic latent image is a melt-kneaded product in which a colorant such as carbon black is dispersed in a binder resin made of natural or synthetic polymer material.
It is used as a two-component developer by pulverizing it to about 20 μm and combining it with magnetic powder such as iron powder, ferrite powder, magnetite powder, etc. with an average particle size of about 100 μm, or a carrier coated with resin. ing.

This developer is triboelectrically charged by being mixed and stirred in the developing device, and the toner is carried to the latent image area on the photoconductive insulator while being supported on the carrier, and only the charged toner is electrostatically charged. Development is accomplished by selectively adhering to the latent image using force.

Next, fixing is the process of melting the toner powder image and fixing it to the recording paper.As mentioned above, there are various methods for this, but flash fixing is the most typical optical fixing method. This is a method of fixing by flashing light from a discharge tube such as a xenon flash lamp, and has the following characteristics.

■Since it is non-contact, there is no reduction in image resolution during development.

■There is no waiting time after turning on the power, allowing a quick start.

■Even if recording paper gets stuck inside the fuser due to a malfunction, it will not cause a fire.

■Can be used regardless of the thickness or material of the recording paper.

Next, the process by which toner is fixed to recording paper by flash fixing is as follows.

When the toner image is transferred to the recording paper, the toner adheres to the recording paper in the form of a powder and easily crumbles when rubbed with a finger.

When a flash from a discharge tube such as a xenon flash lamp is applied to the toner, the toner absorbs the energy of the flash, its temperature rises, it softens and melts, and adheres to the recording paper.

Then, after the flash ends, the temperature of the toner drops, solidifies and becomes a fixed image, and the fixation is completed, and the fixed image fixed on the recording paper is in a state that it will not crumble even if rubbed with a finger.

2) What is important in flash fixing is that the toner melts and firmly adheres to the recording paper, and the toner must absorb light energy from the flash and melt sufficiently.

Therefore, if light energy is insufficient, the toner cannot be sufficiently melted and sufficient fixability cannot be obtained.

On the other hand, if the light energy is too strong, explosive fixation of horse chestnuts will occur and white spots will occur, resulting in a decrease in image density.

FIG. 1 schematically shows this state. As shown in FIG. 1(A), if the irradiation energy is too large, only the toner 2 on the surface will melt. As a result, an umbrella-shaped melt 3 is formed and condensed (FIG. B), and later, when the toner 2 inside is melted, it aggregates and solidifies, thereby creating a void 4 in the center. (C in the same figure) This phenomenon tends to occur when the viscosity at the time of melting (referred to as melt viscosity) is low.

However, until now, low polymer polymers called oligomers have been used as binder resins for toners.

The reason for this is that oligomers have a low molecular weight and therefore have a low melt viscosity, have good adhesion to paper and therefore have good fixing properties, and also have excellent thermal stability.

However, due to the low melt viscosity, the occurrence of voids during flash fixing is unavoidable, which is a problem.

[Problem to be solved by the invention]

As described above, it is necessary for the toner for electrophotographic fixing to exhibit good fixing properties, but it is also necessary that white spots due to voids do not occur in Fra-Sauche fixing.

Here, there is a contradictory relationship: when the melt viscosity is low, the fixing properties are good, but voids are likely to occur.

Therefore, the challenge is to solve this problem.

[Means to solve the problem]

The above problem can be solved by using a polyester resin as an alcohol component constituting the polyester and using either a metal alkoxide or a metal phenoxide as an essential monomer as a binder, adding at least a coloring agent and a charge control agent to this binder, and melting and kneading the resin. This problem can be solved by configuring a toner for flash fixing which is obtained by pulverizing and classifying the toner lumps.

[Effect]

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.

However, when such a resin is used as a binder resin, it is necessary to use an oligomer with a relatively small molecular weight and a low melting point in order to obtain good fixing properties, resulting in a low melt viscosity.

Therefore, the generation of voids was unavoidable during irradiation with flash light.

In order to prevent this, increasing the degree of polymerization of the resin to increase its melt viscosity resulted in a problem in that the melting point of the resin increased, resulting in poor fixing properties and the toner not being sufficiently fused and solidified to the paper. .

Therefore, the inventors proposed a method for increasing the melt viscosity.
Either metal alkoxide or metal phenoxide is used as the alcohol component forming the main chain of the polyester resin used as the binder.

When this is used as an alcohol component, metal atoms are precipitated as metal oxides during the polyester resin synthesis stage.

Therefore, even when using an oligomer that has a relatively small molecular weight, a low melting point, and therefore exhibits good fixing properties, the melt viscosity can be kept high and the generation of voids can be prevented.

Here, examples of the metal alkoxide or metal phenoxide used in the present invention include sodium (Na), potassium (K), and aluminum (An).

Magnesium (Mg), titanium (Ti), beryllium (
Be).

Calcium (Ca), Iron (Fe), ml Balt (Co)
), copper (Cu).

Zinc (Zn), antimony (Sb), tin (Sn),
:- Alkoxides or phenoxides such as nickel (Ni) and manganese (Mn) are mentioned.

Moreover, as an alcohol component which comprises polyester, ethylene glycol, i,3-propylene glycol, 1,2-propylene glycol, trimethylene glycol, and tetramethylene glycol.

1.4-butylene glycol, 1.2-butylene glycol, l,5-pentylene gelicol, pentamethylene glycol, hexamethylene glycol, heptamethylene glycol, diethylene glycol, triethylene glyal, tetramethylene glyal, p- Di(hydroxymethyl)benzene, hydroquinone, hydroquinone di(β-hydroxyethyl) ether, 4-4-
-dihydroxybiphenyl, bis-(4-hydroxyphenyl)ketone, bis-(4-hydroxyphenyl)
Alcohols such as ether, bis-(4-hydroxyphenyl)diphenylmethane, and bis-(4-hydroxyphenyl)sulfone in which some or all of the hydrogen atoms in the hydroxyl groups are replaced with metals can be used alone or in combination.

When making a polyester resin, the present invention uses a polyester resin containing either a metal alkoxide or a metal phenoxide as an essential monomer as an essential alcohol component. This method takes advantage of the fact that the melt viscosity increases due to the release of .

In this case, if the content of the metal oxide contained in the polyester resin used in the present invention is less than 0.5% by weight of the toner weight, no effect of increasing the melt viscosity can be expected.

On the other hand, if the content of the metal oxide is 10% by weight or more based on the weight of the toner, the melt viscosity during toner kneading will extremely increase, which is unsuitable.

For this purpose, it is necessary to adjust the content of metal alkoxide or metal phenoxide in the essential alcohol component constituting the polyester.

The polyether 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, 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 conventionally known methods.

That is, the binder resin 1 colorant, charge control agent, etc. are melt-kneaded and uniformly dispersed using, for example, a pressure kneader, roll mill, extruder, etc., finely pulverized using, for example, a jet mill, and then processed using a classifier such as a wind classifier. A desired toner can be obtained by classifying the toner.

〔Example〕

Example 1: As the alcohol component of the binder resin, 65 parts by weight of aluminum alkoxide (AI0CH2CH20Al) in which the hydrogen (H) of some hydroxyl groups (OH) constituting ethylene glycol (HOCH2CH20H) was substituted with Al7, and as the acid component Terephthalic acid Cc6)[4(CO
2) 2330 parts by weight of 1) was used to obtain a polyester resin in which the content of AA metal oxide was 3% by weight based on the weight of the resin.

To 92 parts by weight of this polyester resin, carbon black (product name: Black Pearls L, manufactured by Cabot Corporation, average particle size 24 mμ, specific surface area 138 m2/g) was added as a coloring agent.
5 parts by weight, metal-containing azo dye (Product name Bontron 5-34
．． 3 parts by weight (manufactured by Orient Chemical Co., Ltd.) were added thereto and melted and mixed for 30 minutes at 130° C. using a pressure kneader to obtain a toner mass.

The cooled toner mass was then ground into ~2 mm coarse toner using a Rotoplex grinder.

Next, the coarse toner was passed through a jet mill (product name: PJM pulverizer 12), and the pulverized product was classified using an air classifier (manufactured by Alpine) to obtain positively charged toner having a particle size of 5 to 20 μm.

A developer consisting of 5 parts by weight of this toner and 95 parts by weight of amorphous iron powder (product name: TSV100/2θO1 made by Nippon Steel Powder) as a carrier was prepared, and a developer was prepared using a laser printer (product name: FACOM).
-67 150 modified machine) was used to conduct a printing test.

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, the toner had no voids at all.

In addition, the melt viscosity of polyester resin was measured by measuring the softening temperature using a flow tester (manufactured by Shimadzu Corporation), and at this temperature
After preheating for 00 seconds, the resin was allowed to flow down by gravity while being maintained at this temperature, and the temperature was determined from the slope of the chart.

As a result, the melt viscosity was 8×10′ voids.

Comparative Example 1: A polyester resin was obtained in the same manner as in Example 1 except that ethylene glycol was used as the alcohol component of the binder resin.

Then, a toner was prepared in exactly the same manner, and a printing test was conducted using this toner.

As a result, a large number of voids were generated, and the melt viscosity was 7XIO'' voids.

〔Effect of the invention〕

As described above, by carrying out the present invention, it is possible to obtain a toner having good flash fixing properties and high melt viscosity.

[Brief explanation of drawings]

In FIG. 1, the white areas are an explanatory diagram of the phenomenon. In the figure, 1 is paper, 2 is toner 4 is boi Do, It is. (A.J. CB) The white outline is an explanatory diagram of the phenomenon. Tsumugi 1 Diagram

Claims (3)

[Claims] (1) As an alcohol component constituting polyester,
A toner for flash fixing, characterized in that a polyester resin containing either metal alkoxide or metal phenoxide as an essential monomer is used as a binder. (2) A polyester resin containing either a metal alkoxide or a metal phenoxide as an essential monomer is used as a binder, at least a colorant and a charge control agent are added to the binder, melted and kneaded to form a toner mass, and the toner mass is crushed and classified. A method for producing a flash fixing toner, characterized in that it is obtained by: (3) In the toner, the content of metal oxide contained in the binder resin is 0.5 to 10% of the weight of the binder resin.
% by weight. The flash fixing toner according to claim 1.