JP3427574B2 - Non-magnetic one-component developing toner composition - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder toner composition used for electrophotographic development.

[0002]

2. Description of the Related Art Powder toner used in electrophotography is
In terms of electrical properties such as triboelectrification and electrical resistance related to development and transfer performance, thermal properties related to fixing performance and heat resistance performance (storage stability), and powder properties such as fluidity and hardness, An appropriate level is required according to the usage conditions.

Conventionally, as a resin material used for powder toner, polystyrene, styrene-acrylic acid ester copolymer, styrene-butadiene copolymer, polyester, epoxy resin, butyral resin, xylene resin, coumarone indene. Resins and the like can be mentioned, and various proposals have been made for the detailed design of resins according to their applications.

In particular, a heat roll fixing resin is required to have improved fixing performance on transfer paper and anti-offset performance. The toner fixing performance is achieved by heating and melting by a fixing roller or the like and binding to the transfer paper, and the offset resistance performance is obtained by melting the toner by the heating roller.
Cold offset does not occur, and hot offset does not occur when viscosity is lost.

A number of design examples have been proposed to achieve these objects. Above all, in order to maintain the viscoelasticity at the time of heating and melting, or to suppress the viscosity change due to temperature change,
Techniques have been studied that include means such as broadening the molecular weight distribution, imparting a crosslinked structure, and applying a rubber elastic material. For example, Japanese Patent Application Laid-Open No. 1-267661 discloses a technique using these means.

Further, as an electrophotographic method, US Pat.
Although various methods are described in Japanese Patent Publication No. 297,691, Japanese Patent Publication No. 42-23910, Japanese Patent Publication No. 43-24748, etc., in general, a photoconductive substance is used, and it is exposed by various means. Form an electrostatic latent image on the body,
Then, the latent image is developed with a developer (electrostatic charge developing toner) to form a visible image, and if necessary, the visible image is transferred to paper or the like and then fixed by pressurization, heating or solvent vapor, A fixed image is obtained.

Although many developing methods are known in the electrophotographic method, they are roughly classified into fine particles of iron powder, ferrite, nickel, glass and the like (20 to 500 μm).
There are a two-component developing method using a mixture of a carrier of m) and a toner as a developer, and a one-component developing method using a developer consisting of only a toner. In either method, generally, the electric charge is triboelectrically injected into the toner.

Typical examples of the two-component developing method include a cascade method described in US Pat. No. 2,618,552 and a magnetic brush method described in US Pat. No. 2,874,063. According to these methods, a good image can be stably obtained, but on the other hand, the surface of the carrier is contaminated by toner and the like, and the image quality is deteriorated due to the change of triboelectrification due to the change of the mixing ratio of the carrier and the toner. Is likely to occur, and it is necessary to devise various devices and materials in order to prevent it.

The one-component developing method avoids the problems of the two-component developing method. For example, US Pat. No. 4,336,318 discloses an electrically insulating magnetic toner. A method of developing is described. In these methods, an electric charge is injected into the toner by frictional electrification between the toner particles and the toner carrier or the toner thinning member, or frictional electrification between the toner particles to form an electrostatic latent image on the photoreceptor. Electrostatically adhere to.

In this developing method, since no carrier is used and a device for controlling the mixing ratio of the carrier and the toner is not required, the problems of the two-component developing method can be avoided and the developing device can be downsized. Has the advantage that

On the other hand, in the same method, in order to form the magnetic brush layer of the toner on the metal sleeve, it is necessary to give the toner itself suitable magnetic characteristics. Therefore, the magnetite,
A magnetic material such as ferrite is an essential material in the toner constituent components. The required content of these magnetic materials is generally 30 to 60% by weight, although it varies somewhat depending on the developing conditions and material type.

However, the inclusion of a large amount of such a magnetic material, which generally has low electric resistance and easily absorbs moisture, causes a decrease in electric resistance and a decrease in humidity resistance of the toner itself, and as a result, a stable developing performance against environmental changes is obtained. It becomes difficult to obtain the image density, and the image density or the background stain level greatly varies in various usage environments.

Further, the fact that the proportion of the resin material as the binder contained in the toner is smaller than that of the two-component toner is a design disadvantage in terms of fixing performance. Furthermore, recently
Considering the increasing use of color images, since many magnetic materials are colored, there are problems that the colors that can be handled are limited or that clear color image quality is difficult to obtain.

In order to solve the problems of the one-component developing method using the magnetic toner, a non-magnetic one-component developing method which does not require magnetic characteristics of the toner has been proposed. Various devices have been studied as such a method, but most of them are ones in which toner is attached to a developing sleeve or the like by electrostatic force, and the toner is conveyed to the latent image surface for development. The developing method is greatly different from the developing method in that the magnetic material is not an essential component in the structure of the toner used, and it can be expected to avoid various problems caused by the inclusion of the magnetic material.

As a non-magnetic one-component developing method, an electrophotographic powder toner containing a binder resin, a colorant and a charge control agent as essential components is used.

Examples of the charge control agent in this case include nigrosine dye, quaternary ammonium salt, trimethylethane dye, copper phthalocyanine, perylene, quinacridone,
Examples thereof include azo pigments, metal complex salt azo dyes, and heavy metal-containing acid dyes such as azochrome complex.

[0017]

In many non-magnetic one-component developing methods, the toner is held and conveyed only by the charging and electrostatic force of the toner. Therefore, when the toner is replenished to the developing sleeve or the like, the toner is instantaneously discharged. However, the toner containing the above-mentioned charge control agent alone as described above is not suitable for continuous printing. However, since the toner charging is not stable, there are various problems such as a decrease in image density and a fog phenomenon in which toner is deposited on a non-image area.

The problem to be solved by the present invention is toner for non-magnetic one-component development which is capable of stably charging not only an initial image but also continuous printing and obtaining a good image.
-Providing a composition .

[0019]

Means for Solving the Problems The present inventors have
As a result of earnest research to solve
It was That is, in order to solve the above problems, the present invention provides a vine
Resin (A), colorant (B), charge control agent (C)
And contains as essential ingredientsToner compositionsmell
hand,As the binder resin (A), aromatic trical
Polybasic acids containing boric acid or its derivatives and polyhydric alcohols
Using a polyester resin that has reacted withThe charge control
Agent(C)As at least the following formula (1) andformula
Characterized by using two kinds of charge control agents represented by (2)
Non-magnetic one-component development tonerCompositionI will provide a.

Equation (1)

[0021]

[Chemical 3]

Equation (2)

[0023]

[Chemical 4]

In the present invention, as the binder resin (A), any of known and commonly used binder resins can be used. For example, polystyrene, styrene- (meth) acrylic acid ester copolymer, styrene-butadiene copolymer, polyester resin, Examples thereof include epoxy resin, butyral resin, xylene resin, coumarone indene resin, and the like. This may be used alone or in combination of two or more kinds.

Binder resin (A) usable in the present invention
Among them, polyester resins are preferable because they have good fixing performance while maintaining running durability. The polyester resin can be obtained, for example, by ester condensation of a polybasic acid containing a dicarboxylic acid and a polyhydric alcohol as essential components. Of course, an ester-forming derivative may be used as the polybasic acid and the polyhydric alcohol, and the transesterification reaction may be performed to obtain it.

The specific method for obtaining the polyester resin is not particularly limited, and it can be easily synthesized by polycondensation in a known solution. However, a diol component as a polyhydric alcohol and a polybasic acid are used. Can be obtained by using a dicarboxylic acid component as the compound and a carboxylic acid having a valence of 3 or more.

Examples of the diol component to obtain a polyester resin, such as ethylene glycol, propylene glycol, butanediol, diethylene Les glycol,
Triethylene glycol, tetraethylene glycol,
Examples thereof include hexanediol, neopentyl glycol, cyclohexanedimethanol, hydrogenated bisphenol A, propylene oxide adduct of bisphenol A, and ethylene oxide adduct of bisphenol A.

Examples of the dicarboxylic acid component include maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid, phthalic anhydride, terephthalic acid, isophthalic acid, orthophthalic acid, hexahydrophthalic anhydride and tetrahydrophthalic anhydride. , Cyclohexanedicarboxylic acid,
Examples thereof include succinic acid, malonic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, mesaconic acid, metaconic acid, glutaconic acid and cyclohexanedicarboxylic acid.
Of course, these anhydrides and lower alkyl esters can also be used.

Examples of the trivalent or higher carboxylic acid component include trimellitic acid, toluentrycarboxylic acid, cyclohexanetricarboxylic acid, naphthalenetricarboxylic acid, butanetricarboxylic acid and other tricarboxylic acids, tetra (methylenecarboxylic) methane, pyromellitic acid and the like. Tetracarboxylic acid etc. are mentioned. Of course, these anhydrides and lower alkyl esters can also be used. Of these, trimellitic anhydride is preferable.

A polyester resin using a polybasic acid having an aromatic ring and / or a polyhydric alcohol is preferable because it has good blocking resistance. In particular, a polyester resin obtained by reacting a polybasic acid containing an aromatic tricarboxylic acid or its derivative with a polyhydric alcohol is most preferable.

The polyester resin can be usually obtained by carrying out a dehydration condensation reaction or a transesterification reaction using the above raw material components in the presence of a catalyst in an organic solvent.
The reaction temperature and reaction time at this time are not particularly limited, but are usually 20 to 200 ° C. and 30 minutes to 24 hours.

As other components in carrying out the above reaction, esterification catalysts and transesterification catalysts such as magnesium acetate, zinc acetate, manganese acetate, lead acetate, antimony trioxide, germanium dioxide, zinc oxide, and oxidation are used as other components for the purpose of promoting the reaction. Stannous tin, dibutyltin oxide, dibutyltin dilaurate and the like can be used as appropriate.

The binder resin has only to have a glass transition point and a melt viscosity characteristic suitable for a non-magnetic one-component developing toner, and the temperature at which the viscosity becomes 1 × 10 ⁵ poise is 105 ° C. or higher. However, in the case of the polyester resin, the temperature at which the viscosity becomes 1 × 10 ⁵ poise is preferably 105 to 170 ° C.

The acid value of the polyester resin is 15 m
It is preferably gKOH / g or less from the viewpoint that the moisture resistance of the toner is good.

On the other hand, its glass transition temperature (Tg) is 5
It is preferably 7 ° C or higher, but the Tg is 5
Those of 7 to 83 ° C. are particularly preferable.

As the colorant (B), various non-magnetic organic pigments and inorganic pigments can be used. Specifically, for example, carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue. ,
DuPont Oil Red, Quinoline Yellow, Methylene Blue Chloride, Phthalocyanine Blue, Malachite Green Oxalate, Lamp Black, Rose Bengal,
C. I. Pigment Red 122, C.I. I. Pigment Yellow 97, C.I. I. Pigment Blue 15 and the like, and they may be used alone or in combination of two or more.

[0037] as a car carbon black is, for example Mogul L, Elf Tex (ELFTEX) 8 (manufactured by the United States Cabot Corporation), and the like MA100 [manufactured by Mitsubishi Chemical Co., Ltd.].

In the toner of the present invention, the weight ratio of the resin (A) and the colorant (B) is not particularly limited, but the colorant (B) is usually 1 to 60 per 100 parts by weight of the resin (A).
Parts by weight, preferably 3 to 30 parts by weight.

The composition of the present invention is most characterized in that the following two specific charge control agents (C) are used in combination.

[0040]

[Chemical 5]

[0041]

[Chemical 6]

[0042] While the weight ratio is not particularly limited in the charge control agent, preferably the formula (1) and (2)
It is desirable to use them in a weight ratio of 40/60 to 60/40, where 100 is the total weight of the two types of charge control agents.

Further, it is desirable to use a total of 0.5 to 3 parts by weight of these per 100 parts by weight of the solid content of the binder resin (A).

In obtaining the toner of the present invention, various auxiliaries such as a charge control agent, a release agent and a fluidity improver can be added in any step of its production. It is effective to attach the fluidity improver to the toner surface.

Other known and conventional compounds which can be used in combination with the charge control agent (C) include, for example, nigrosine dyes,
A quaternary ammonium salt, a trimethylethane dye, copper phthalocyanine, perylene, quinacridone, an azo pigment, a metal complex salt azo dye, a heavy metal-containing acid dye such as an azochrome complex, and the like are used as necessary.

Further, in heat roll fixing applications, various waxes are optionally used as an auxiliary agent for enhancing the releasing effect for the purpose of preventing troubles due to the toner sticking to the heat roll (offset). For example, montanic acid. Natural wax such as ester wax, polyolefin wax such as high-pressure polyethylene, polypropylene, silicone wax, fluorine wax and the like can be used.

Suitable waxes include, for example, Viscole 660P, Viscole 550P and Viscole 330.
P, TP-32 (manufactured by Sanyo Kasei Co., Ltd.), Mitsui High Wax NP505, P200, P300, P4
There is 00 etc.

Examples of lubricants include metal soap and zinc stearate, and examples of abrasives include cerium oxide and
Silicon carbide or the like can also be used.

The toner of the present invention can be obtained by any known and commonly used production method. For example, the resin (A) and the colorant (B) are above the melting point (softening point) of the resin (A). It can be obtained by melt-kneading, pulverizing and classifying. Of course, it may be manufactured by a method other than this.

Specifically, for example, the resin (A) and the colorant (B) are mixed as essential components by a kneading means such as a two-roll, a three-roll, a pressure kneader, or a twin-screw extruder. To do. At this time, the colorant (B) may be uniformly dispersed in the resin (A), and the conditions of the melt-kneading are not particularly limited, but usually at 80 to 180 ° C. for 10 minutes to
2 hours.

In the kneading, for example, the binder resin (A), the colorant (B) and the release agent are mixed with the colorant 1 to 10.
It may be prepared in advance so that the amount of the release agent is 0.5 to 5% by weight and the balance is the binder resin (A) and the charge control agent (C).

Then, after cooling, it is finely pulverized by a pulverizer such as a jet mill and classified by an air classifier or the like. The toner particles have an average particle size of 1
It is preferably ˜15 μm.

The toner powder of the present invention can be used as it is as a powder toner for electrophotography, but by externally adding silica, the powder fluidity and the like can be further improved and it is practically suitable. Is.

Examples of the silica used in the present invention include those having hydrophobicity among silicon dioxide, and examples thereof include those obtained by surface-treating silicon dioxide with various polyorganosiloxanes, silane coupling agents and the like. . For example, there are products marketed under the following trade names.

AEROSIL R972, R974, R
202, R805, R812, RX200, RY20
0, R809, RX50 [Japan Aerosil Co., Ltd.]

WACKER HDK H2000, H2
050EP [Wacker Chemicals East Asia Co., Ltd.] Nipsil SS-10, SS-15, SS-20,
SS-50, SS-60, SS-100, SS-50
B, SS-50F, SS-10F, SS-40, SS-
70, SS-72F [Nippon Silica Industry Co., Ltd.]

As silica, there are silica having a relatively large average particle diameter and silica having a relatively small average particle diameter, and these may be used alone or in combination. As the amount of silica added externally, a charge amount is necessary and sufficient, which does not damage the photoconductor drum or worsen the environmental characteristics of the toner.
Practically suitable is 0.1 to 5.0 parts by weight.

The silica may be externally added to the toner particles by using, for example, an ordinary powder mixer such as a Henschel mixer, or a so-called surface modifier such as a hybridizer. Incidentally, this external addition may be carried out by attaching silica to the surface of the toner particles, or by embedding a part of the silica in the toner particles.

As a one-component developing method using a non-magnetic toner, there is a contact-type non-magnetic one-component developing method in which a developing sleeve carrying a developer is brought into contact with a photosensitive drum having an electrostatic latent image for development. .

The toner obtained in the present invention is passed through a space between a developing sleeve and a charging member pressed against the developing sleeve, and the toner is triboelectrically charged to form an electrostatic latent image formed on the surface of the photosensitive member. It can be particularly effectively used for a contact-type non-magnetic one-component developing method for developing a toner.

[0061]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples. In the following, the numerical values in the composition table represent "parts by weight" and "% by weight", respectively. First, a synthetic example of the binder resin used for preparing the toner is shown below.

(Example of resin synthesis) Bisphenol A68
A mol part, 16 mol parts of terephthalic acid, 10 mol parts of trimellitic anhydride, 5 mol parts of ethylene glycol and 0.06 mol parts of dibutyltin oxide were charged into a flask and reacted at 220 ° C. under a nitrogen atmosphere for about 20 hours to give a polyester resin. Synthesized.

The obtained polyester resin has an acid value of 10,
The temperature at which the melt viscosity became 1 × 10 ⁵ poise was 164 ° C. and the glass transition temperature (Tg) was 70 ° C.

Example 1 and Comparative Examples 1 and 2 Based on the following compounding ratios in Table 1, the polyester resin (resin A in the table) and the charge control agent of the formula (1) [in the table, CC
A (1)], a charge control agent of the formula (2) [in the table, CCA
(2)], Elftex 8 (carbon black powder, carbon with surface) made by Cabot Corporation of the United States, Viscor 550P
[Sanyo Kasei Co., Ltd. polypropylene wax, in the table,
Wax, respectively, blended, melt-kneaded,
50% volume average particle size 10.5 μm
Toner was obtained. AEROSIL R972 [Japan Aerosil Co., Ltd.
0.5% by weight of hydrophobic silica] was externally added to obtain a toner composition of the present invention.

[0065]

[Table 1]

Each of the toners obtained in Table 1 above was evaluated for continuous printing on 8000 sheets by a printer using a developing machine described below. The results are shown in Table 2. The toner composition of Example 1 had stable image density, and an image with less fog was obtained. Regarding the difference between ○ and ◎ in the fog evaluation, ○ is a practically no problem level in visual evaluation, and ◎ is an even better level.

On the other hand, each of the toner compositions of the comparative examples resulted in a printed image which had a problem in practical use due to unstable image density and a large amount of fog. The evaluation of fogging x is a level at which there is a problem in visual evaluation.

[0068]

[Table 2]

Examples 2 to 12 Toner compositions were prepared as shown in Table 3 in the same manner as in Example 1 above, and the results of evaluation by the same evaluation criteria as above are shown in Table 4.

[0070]

[Table 3]

[0071]

[Table 4]

[0072]

The toner composition of the present invention according to the present invention, since a combination of two kinds of charge control agent having a specific structure, the image density is stable from the initial to the large number, the fog is extremely small, non-magnetic The one-component system has a particularly remarkable effect that it has a sufficient continuous running performance for practical use and can stably provide a good image quality even when developing a large number of sheets.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a developing machine used in a continuous printing test in Examples and Comparative Examples of the present invention.

[Explanation of symbols]

1 developing roll 2 Charging blade 3 Toner supply roll 4 stirring rolls 5 Toner hopper 6 Toner room 7 photoconductor

─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-4-360155 (JP, A) JP-A-6-332240 (JP, A) JP-A-3-67268 (JP, A) JP-A-3- 131869 (JP, A) JP-A-7-306545 (JP, A) JP-A-5-53376 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 9/097 CA ( STN) REGISTRY (STN)

Claims (6)

(57) [Claims] 1. A binder resin (A) and a colorant (B).
And a charge control agent (C) as essential components
In the toner composition , the binder resin (A)
, Polybasic containing aromatic tricarboxylic acid or its derivative
Polyester resin made by reacting acid and polyhydric alcohol
The used, the as a charge control agent (C), at least the following formula (1) and non-magnetic one-component developing toner composition characterized by using two kinds of charge control agents represented by the formula (2). [Chemical 1] Formula (1) Formula (2) When wherein that in the formula (1) and (2) 100 two the total weight of the charge control agent represented by them 4
The non-magnetic one-component developing toner composition according to claim 1, which is used in an amount of 0/60 to 60/40 (weight ratio). When wherein that in the formula (1) and 100 the total weight of the two charge control agent represented by the formula (2), they 4
The non-magnetic one-component developing toner composition according to claim 1, which is used in an amount of 0/60 to 60/40 (weight ratio), and is used in a total amount of 0.5 to 3 parts by weight per 100 parts by weight of the binder resin. 4. A polypropylene wack as a release agent.
The non-woven fabric according to claim 1, 2 or 3 containing
Toner composition for magnetic one-component development. 5. A developing sleeve and a photosensitive drum are brought into contact with each other.
Claim to use in contact type non-magnetic one-component developing device for developing
Item 5. The toner composition according to any one of items 1, 2, 3 and 4. 6. The method according to claim 1, 2, 3 or 4.
Of the toner composition on the developing sleeve, and
Contact-type non-magnetic one-component developing method that develops in contact with ram
Law.