JPS62270964A - Flash fixing electrophotographic toner - Google Patents

Abstract

PURPOSE:To obtain the titled toner having an increased melt viscosity of a resin, without raising a melting point thereof by using the resin modified a bisphenol A type epoxy prepolymer with amidated primary or secondary amine which is obtd. by reacting equimolar of an aliphatic monocarboxylic acid and the primary or the secondary diamine as a binder. CONSTITUTION:The compd. usable for the binder is formed by modifying the bisphenol A type epoxy prepolymer with the amidated primary or secondary amine which is obtd. by reacting equimolar of the aliphatic monocarboxylic acid contg. at least 50mol% >=10 C higher aliphatic acid unit in constituent unit with the primary of the secondary diamine, thereby forming a modified epoxy resin compd. which has a softening point of 70-160 deg.C by ring and ball method, and a weight average molecular weight of 2,000-50,000. The compd. is used for the binder. Thus, as the amide compd. has a low molecular weight, the amide compd. does not have an effect of raising the softening point, and the softening point of the epoxy compd. does not change. However, in a melted state, the melt viscosity of the epoxy compd. increases by twisting the amide compds. at the terminal of the epoxy compd. with each other.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [1 Already Required] Amidated primary and secondary diamines obtained by equimolar reaction of aliphatic monocarboxylic acids and primary and secondary diamines By using a resin modified with an amine as a binder for a flash fixing toner, it melts without raising the melting point, compared to a toner made only of bisphenol A diglycidyl ether polymer, which has the same melting point. Toner with increased viscosity.

[Industrial application field]

The present invention relates to a toner whose melt viscosity is increased without increasing its melting point.

Conventionally, as an electrophotographic method, a method described in US Pat. No. 2,297,691 and the like is well known.

This uses a photoconductive insulator, applies a uniform electrostatic charge on the insulator by corona discharge, and forms an electrostatic latent image by irradiating the insulator layer with a light image by various means. Insulating powder called toner is electrostatically attracted to the latent image, developed and visualized, and then this toner image is transferred to paper.
Pressurize this.

Copies are obtained by fixing using heat, solvent vapor, light, etc.

Here, as a toner for developing an electrostatic latent image, a coloring agent such as carbon black is conventionally dispersed in a binder resin (hereinafter referred to as a binder) made of a natural or synthetic polymer material. Particles pulverized to a size of about 1 to 30 μm are used.

Then, such toner is mixed with a carrier material such as iron powder or glass beads to form a developer, which is used for developing an electrostatic latent image.

The present invention relates to improving the properties of such toner.

[Conventional technology]

There are various methods for fixing toner made visible by developing an electrostatic latent image, but flash fixing using a discharge tube such as a xenon lamp is generally used because of the following characteristics.

■ Non-contact fixing does not degrade image resolution during development.

■ No waiting time is required after the power is turned on, and immediate start is possible.

■ Even if recording paper gets jammed inside the fuser due to system failure, the paper will not burn.

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

Here, to explain the process by which toner adheres to recording paper by flash fixing, the toner transferred to recording paper adheres to the recording paper as a powder, forming an image, which crumbles when rubbed with a finger.

Next, when a flash of light is irradiated using a discharge tube such as a xenon Franche lamp, the toner absorbs the energy of the flash, and as a result its temperature rises, softens and melts, and adheres closely to the recording paper.

After the flash ends, the temperature drops and solidifies to produce a fixed image.

Here, the requirements for the toner are that it softens at a relatively low temperature and that the image does not deform even in the molten state.

However, when solids, not just toner, melt, their viscosity decreases,
Surface tension causes the melt to condense and deform, in which case the toner image is deformed.

Conventionally, low polymer polymers called oligomers have been used as binders for toners because they have low melting temperatures and good thermal stability.

However, due to the low melt viscosity, the fixed image is easily deformed and the image quality is degraded, which is a problem. Also, explosive fixing is likely to occur, which causes white spots called voids in the image, resulting in a decrease in image density. The problem is that it is decreasing.

Therefore, it is necessary to improve the toner so that it exhibits good fixing properties and does not cause the void phenomenon. [Problems to be solved by the invention] As described above, oligomers are used as binders in electrophotographic toners. However, due to the low melt viscosity, condensation easily occurs, which causes deformation of the fixed image.
The problem is that it causes a decline in image quality.

[Means for solving problems]

The above problem can be solved by amidation, which is obtained by reacting equimolar amounts of primary and secondary diamines with an aliphatic monocarboxylic acid in which at least 50 mol% of the constituent components are higher fatty acid units having 10 or more carbon atoms. Bisphenol A type epoxy prepolymer is modified using primary and secondary amines to achieve a weight average molecular weight of 2,000 to 50,000 and a ring and ball softening point of 7.
This problem can be solved by forming a terminal amide-modified epoxy resin compound having a temperature of 0 to 160 DEG C., and using an electrophotographic toner for Franche fixing using this compound as a binder.

[Effect]

In order to prevent conventional toner from condensing due to its low melt viscosity and deteriorating image quality, it is necessary to increase the melt viscosity without changing the binder's softening temperature so that it has enough viscosity to overcome the surface tension. In this case, there should be no deterioration in image quality.

In order to solve this problem, the inventors used, as a binder, a terminal amide-modified epoxy compound in which a low molecular weight amide compound was reacted with the molecular terminal of the epoxy compound.

In this way, since the amide compound has a low molecular weight, it does not have the effect of increasing the softening temperature of the epoxy compound, so the softening temperature does not change, but in the molten state, the amide compounds provided at the ends of the epoxy compound become entangled with each other. Therefore, the molecular motion of the epoxy compound is suppressed, making it difficult to move, and as a result, the melt viscosity increases.

In this manner, the present invention increases only the melt viscosity while hardly changing the softening temperature of the binder.

In the present invention, the amide compound consists of an aliphatic monocarboxylic acid, a primary diamine, and a secondary diamine, and the epoxy compound contains bisphenol A diglycidyl ether containing at least two or more epoxy groups in one molecule. It is constructed as a unit.

Here, the aliphatic monocarboxylic acid mentioned above must have at least 50 mol% of its constituent components consisting of higher fatty acid units having 10 or more carbon atoms, and the primary and secondary diamines must be contained in 1. ．． 2. ．． 3. ,
As shown in the example, it is formed from one of a cyclic diamine, an aromatic diamine, and a linear diamine.

Then, an aliphatic monocarboxylic acid, a primary diamine, and a secondary diamine are reacted in equimolar amounts to produce an amidated primary amine and a secondary amine, and the bisphenol A-type epoxy prepolymer is modified with this, This is used as a binder.

The binder thus obtained has a weight average molecular weight of 2
000~50000 Also, the softening temperature by ring and ball method is 80~
160"C, and a binder suitable for electrophotographic toners can be obtained.

Next, the names of chemicals and materials applicable to the present invention are listed as follows.

Aliphatic monocarboxylic acids: caproic acid, enanthic acid, caprylic acid, pelargonic acid,
Capric acid, undecylic acid, lauric acid.

Tridecylic acid 1 myristic acid, pentadecylic acid.

Valmitic acid, heptadecylic acid, stearic acid.

Saturated fatty acids such as nonadecanoic acid, arachidic acid, undecylenic acid, oleic acid, elaidic acid, cetoleic acid, erucic acid, sorbic acid, linoleic acid.

unsaturated fatty acids such as lyrinic acid;

Cyclic diamine: hyherazine, N-aminoethylpiperazine, N-7 minoprobilbiperazine, 1,3-(4-piperazi4)propane, N,N-diaminoethylpiperazine, isophoronediamine, 1,3-diaminocyclohexane, m-xylene diamine, menthanediamine, etc.

Aromatic diamine: 0-phenylenediamine, p-phenylenediamine.

l-phenylene diamine, 4,4-methylene dianiline.

benzidine, 2.4-) luenediamine, etc.

Linear aliphatic diamines: ethylene diamine, propylene diamine, hexamethylene diamine, stearylpropylene diamine, ethylaminoethyl diamine, etc.

Bisphenol-type epoxy resin: (Product name containing bisphenol A diglyl ether as a repeating unit/trade name) Shell's "Epicor" j 828.834.100
1.1004, 1007 and 1009, Ciba Geigy's "Araldite J 6071.70
7L 7072.6084.7097.6097 and 6099, Dow rD, E, R, J 660.661
．． 662, 664, 667, 668 and 669, [Epicron J 105Q] from Dainippon Ink and Chemicals.

3050, 4050.7050° Both are available on the market.

In the production of the amide-modified epoxy resin according to the present invention, the reaction between the aliphatic monocarboxylic acid and the primary and secondary diamines is preferably carried out at about 200°C in an inert atmosphere.

Further, at this time, the reaction rate can be accelerated by using a catalyst or promoter used in the production of general polyamides.

Furthermore, when using an unsaturated monocarboxylic acid, it is desirable to add a small amount of a polymerization inhibitor, such as hydroquinone.

Further, the reaction between the epoxy resin and the amidated primary and secondary amines is preferably carried out at about 150°C.

Next, the toner according to the present invention can be manufactured by a known method.

That is, if necessary, a charge control agent such as polyamine is added to the binder and colorant, and the mixture is mixed using a pressure kneader, roll mill, extruder, etc. ! 12. The desired toner can be obtained by melting and uniformly dispersing the toner, then pulverizing it using a pulverizer, jet mill, etc., and then classifying it using an air classifier.

〔Example〕

Example 1: 1-1 (Production example of toner using amide-modified epoxy resin using cyclic diamine and printing test results) Amide-modified epoxy resin using N-aminoethylpiperazine as cyclic diamine (trade name TNEP-11) , manufactured by Sanwa Chemical Industry, melting point: 98°C, weight average molecular weight: 1173
0) 5 parts by weight of carbon black and 3 parts by weight of nigrosine dye were added to 92 parts by weight, and the mixture was melted and kneaded at 130° C. for 30 minutes using a pressure kneader to obtain a toner mass.

Next, this was crushed to obtain a coarse toner, and a toner having a particle size of 5 to 20 μm and an average particle size of 11.2 μm was obtained using a jet mill.

5 parts by weight of this toner, unshaped iron powder TSV as a carrier
100/200 (Japanese iron powder type) FA that adjusts developer consisting of 95 parts by weight and adopts flash fixing method.
A printing test and a fixing test were conducted using a COM-6715D laser printer.

The setting conditions for the fixing device were such that a capacitor with a capacitance of 160 μF was used, the charging voltage was kept constant at 2050 V, and this was applied to the flash lamp.

In addition, the fixation was evaluated by lightly applying adhesive tape (Scotch Mending Tape, manufactured by Jujutsu 3M Co., Ltd.),
A 20 mm thick iron cylindrical block is rolled over this tape at a constant speed in the circumferential direction to bring the tape into close contact with the recording paper.Then, the tape is peeled off and the optical density after peeling is compared to the optical density of the image before peeling. The fixability was evaluated by expressing the ratio as a percentage.

The optical density was measured using a PCM meter manufactured by Macbeth.

The results of the fixing test showed that the toner fixation rate was 100%, indicating excellent fixing properties, very few voids caused by explosive fixing, and the optical density (abbreviated as 00) of the image was 1.22.
It showed a high degree of blackness.

■-2 (Comparative example) Epoxy resin with the same melting point as used for amide modification (
Epicote 1004. (manufactured by Shell Yuka), a toner was made using the same method as described in 1-2 with a composition of 92 parts by weight of resin, 5 parts by weight of carbon blank, and 3 parts by weight of dye, and 5 parts by weight of this toner was prepared in the same way as before. Similar printing tests and fixing tests were conducted using a developer consisting of 95 parts by weight of amorphous iron powder carrier and 95 parts by weight of amorphous iron powder carrier.

As a result, the fixation rate was relatively good at 90%, but many large nest-like voids due to explosive fixation were observed in the fixed image. Only a low image of =0.85 was obtained.

Example 2 (Manufacturing example and printing test results of toner using amide-modified epoxy resin using linear aliphatic diamine) Amide-modified epoxy resin (trade name: TNEP-18) using hexamethylene diamine as the linear aliphatic diamine ．．
Manufactured by Sanwa Kagaku Kogyo Co., Ltd., melting point 99°C), add 5 parts by weight of carbon blank and 3 parts by weight of nigrosine dye to 4 parts of 92-fold,
A toner having a particle size of 5 to 20 μm and an average particle size of 11.2 μm was obtained by the same method as described in 2.

A developer consisting of 5 parts by weight of this toner and 95 parts by weight of amorphous iron powder TSV100/200 as a carrier was prepared in the same manner as before, and a printing test and a fixing test were conducted in the same manner as before.

As a result, the fixing rate of the toner was 100%, showing excellent fixing properties, and the occurrence of voids was extremely small, and the optical density of the image was 0.0. = 1.20, showing a high degree of blackness.

Example 3 (Manufacturing example and printing test results of toner using amide-modified epoxy resin using aromatic diamine) Amide-modified epoxy resin (trade name: TNEP-22) using 4,4-methylene dianiline as aromatic diamine (manufactured by Sanwa Kagaku Kogyo Co., Ltd., melting point: 100°C), 5 parts by weight of carbon black and 3 parts by weight of nigrosine dye were added, and the same method as described in 1-2 was used to obtain particles with a particle size of 5 to 20 μm and an average particle size of 11. 2μm
I got the toner.

A developer consisting of 5 parts by weight of this toner and 95 parts by weight of amorphous iron powder TSVI00/200 as a carrier was prepared in the same manner as before, and a printing test and a fixing test were conducted in the same manner as before.

As a result, the toner fixation rate was 100%, showing excellent fixing properties, and the occurrence of voids was extremely small, and the optical density of the image was 0. It showed a high degree of blackness, D = 1.25.

〔Effect of the invention〕

As described above, by carrying out the present invention, it is possible to improve the melt viscosity of the toner without substantially changing its melting point, thereby making it possible to improve the image quality.

[Brief explanation of drawings]

The figure is an example of a structural formula of a diamine used in the present invention.

Claims (4)

[Claims] (1) Amidated primary compound obtained by reacting an aliphatic monocarboxylic acid, of which at least 50 mol% of the constituent components is composed of higher fatty acid units having 10 or more carbon atoms, with primary and secondary diamines in equimolar amounts. , using a secondary amine to modify a bisphenol A type epoxy prepolymer to form a terminal amide-modified epoxy resin compound having a weight average molecular weight of 2,000 to 50,000 and a ring and ball softening point of 70 to 160°C; An electrophotographic toner for flash fixing, characterized in that it uses as a binder. (2) The electrophotographic toner for flash fixing according to claim 1, wherein the primary and secondary diamines are cyclic diamines. (3) The electrophotographic toner for flash fixing according to claim 1, wherein the primary and secondary diamines are linear diamines. (4) The electrophotographic toner for flash fixing according to claim 1, wherein the primary and secondary diamines are aromatic diamines.