JPH05119513A - Dry toner for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To ensure narrow distribution of an electrostatically charged state, high electrostatic chargeability, satisfactory electrostatic charge retentivity and satisfactory electric charge exchangeability by fixing an electrostatic charge controlling agent on the surface of a toner contg. a uniformly dispersed electrostatic charge controlling resin. CONSTITUTION:An electrostatic charge controlling resin is incorporated into a dry toner for developing an electrostatic charge image contg. at least a binding resin and a colorant as essential components and an electrostatic charge controlling agent is added to the toner. Since the electrostatic charge controlling resin is incorporated into the toner, the dispersibility of the resin in the toner particles is improved and uneven existence of the inner electrostatic charge controlling component among the toner particles and the concentration of the component in the surface layers of the toner particles can be prevented. Since the electrostatic charge controlling agent is added to the toner, uneven existence of the electrostatic charge controlling component in the surface layers of the toner particles can be suppressed. Since the added controlling agent is not electrostatically stuck but is fixed on the surfaces of the toner particles by mechanical force with a Henschel mixer, etc., the impaction of the controlling agent on a carrier and a photosensitive body is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry toner for developing an electrostatic charge image used for developing an electrostatic latent image in electrophotography and electrostatic recording.

[0002]

2. Description of the Related Art In electrophotography, a photoconductive substance such as selenium is used as a photoconductor to form an electrostatic latent image by various methods, and a toner is formed on the electrostatic latent image by a magnetic brush developing method. The method of attaching and visualizing is generally adopted. The developing toner used there carries various positive and negative charges depending on the polarity of the electrostatic latent image to be developed by various friction charging methods. By the way, the charging performance of the developing toner can be secured to some extent by the thermoplastic binder resin which is the main component of the toner, but it is not sufficient. When the chargeability of the toner is not proper, problems such as fogging, a decrease in density and the like in image characteristics and a short life occur. Therefore, many methods have been proposed for the purpose of solving the above problems by adding a charge control agent to the toner.

For example, a method in which a binder resin and a charge control agent are kneaded, such as a kneading and pulverization method, and the distribution of the charge control agent on the toner surface is controlled, thereby eliminating charge variations among toner particles. , Get a stable charge, for example,
A method of externally adhering a charge control agent or forming a layer on the surface of the toner containing no charge control agent (JP-A-63-27854, JP-A-63-85755, JP-A-63-1).
No. 04064, Japanese Patent Laid-Open No. 63-131148,
JP-A-64-72168, etc.) or a charge control agent added internally, and a method of additionally adding and fixing from the outside (JP-A-63-289558, JP-A-2-73).
No. 371, etc.), and further, by controlling the distribution of the charge control component inside the toner, stable charging can be obtained by eliminating the variation in charge among the toner particles.
Many methods are known, such as the method of simultaneously and internally adding a charge control agent and a charge control resin described in JP-A-167565.

[0004]

However, it is difficult to disperse the charge control agent finely and uniformly in the method of kneading the binder resin and the charge control agent like the kneading and pulverization method.
Therefore, it tends to exist as an aggregate in the toner.
At the time of crushing, the interface of the aggregate easily breaks, and as a result, the charge control agent is present on the toner surface due to the crushing. Therefore, although the charging speed becomes faster, the charge distribution becomes wider because the amount of the surface charge control agent varies among the toner particles, and the amount of the charge present in the toner also differs due to poor dispersion, resulting in charge exchange and charging. There is a problem that maintainability deteriorates.

Further, in the method of controlling the distribution of the charge control agent on the toner surface to eliminate the charge variation between the toner particles and obtain a stable charge, a large amount of the charge control agent is present on the toner surface layer, and Variations in charging ability between toner particles are reduced. Therefore, the charge distribution becomes sharp, but if the charge control agent inside the toner becomes more dominant with respect to the charge behavior over time, the distribution will be different or nonexistent among the toner particles. There are still problems with maintainability.

Furthermore, in the method of controlling the distribution of the charge control component inside the toner to eliminate the charge variation between the toner particles and obtain a stable charge, the influence of the aggregate of the charge control agent is eliminated inside the toner. Because I can't handle it
The effect of improving the charge maintaining property is small, and the distribution of the charge control agent among the toner particles is uneven on the surface. Therefore, the charge distribution becomes wide, and a problem occurs in charge exchange. As described above, all of the conventional methods of adding a charge control agent to a toner have various characteristics required for the toner, that is, a narrow charge distribution, high chargeability, good charge retention and good charge exchange characteristics. Even if some of the above are solved, not all of them can be satisfied.

The present invention has been made in order to solve the problems in view of the above-mentioned actual state of the prior art. That is,
The object of the present invention is to achieve a narrow charge distribution, high chargeability, good charge maintainability, and good charge exchangeability by externally adding a charge control agent to the surface of toner particles in which a charge control resin is uniformly dispersed. Another object of the present invention is to provide a dry toner for developing an electrostatic image.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present inventors have found a relationship between the presence state of a charge control agent on the toner surface layer and inside thereof and the chargeability, charge exchangeability, and charge maintainability of the toner. As a result of various investigations focusing on the fact, the initial charging behavior is affected by the charge control agent on the surface layer of the toner particles, and the effect of the charge control agent inside the toner gradually appears over time. When the charge control agent is present, it has excellent charge exchange properties and high chargeability, but the charge retention becomes poor, and when a large amount of the charge control agent is present inside the toner particles, the charge retention property becomes poor. It was found that the chargeability was poor, but the chargeability was low, especially the charge speed was slow, although it was excellent. Then, they have found that the above object of the present invention can be achieved by improving the dispersibility of each of the charge control components existing in the surface layer of the toner particles and inside thereof, and have completed the present invention. That is, the present invention relates to a dry toner for developing an electrostatic image containing at least a binder resin and a colorant as essential components, in which a charge control resin is internally added to toner particles, and a charge control agent is externally added and contained. It is characterized by being

The present invention will be described in detail below. As described above, the toner of the present invention contains a charge control resin internally and a charge control agent externally added to a dry toner for electrostatic image development containing at least a binder resin and a colorant as essential components. It was made. In such a toner, by internally adding the charge control resin, the dispersibility of the charge control resin in the toner particles is improved, and the dispersion of the internal charge control component among the toner particles and the charge control on the surface layer of the toner particles are controlled. It is possible to eliminate the concentration of the components, and by externally adding the charge control agent, it is possible to reduce the variation in the presence of the charge control component on the surface layer of the toner particles.

Examples of the charge control resin of the present invention include a positive charge control resin represented by the following general formula (I) and a negative charge control resin represented by the general formula (II). Are not limited to these.

[0011]

[Chemical 1] (In the formula, R ₁ , R ₅ and R ₆ each represent a hydrogen atom or a methyl group, R _{2 to} R ₄ each represent an alkyl group having 1 to 5 carbon atoms and a benzyl group, and X
^- represents an anion. Further, n and n ′ are 1 to
Means an integer of 5, k, l, and m are monomer ratios, and k is an integer of 0 or 1 or more, l and m
Means an integer of 1 or more. )

[0012]

[Chemical 2] (Wherein R ₁ and R ₇ represent a hydrogen atom or a methyl group, R ₈ and R ₉ represent a hydrogen atom or an alkyl group, and y and z represent a monomer ratio, x means an integer of 1 to 10, y and z
Means an integer of 1 or more. ) The amount of charge control resin added is 0.1 based on the total weight of the toner.
To 20% by weight, more preferably 0.5
Is in the range of up to 5% by weight.

As the externally added charge control agent in the present invention, any positive or negative charge control agent can be used as long as it is known. Examples of the positive charge control agent include quaternary ammonium salt compounds, organic dyes, particularly basic dyes and salts thereof, and negative charge control agents include chromium-containing monoazo complexes, salicylate metal complex compounds, and the like. Examples include chloro organic dyes. The amount added is preferably in the range of 0.1 to 10% by weight, more preferably 0.5 to 3% by weight, based on the total weight of the toner. Further, the particle diameter is preferably 3 μm or less, more preferably 1 μm or less.

These charge control agents may be electrostatically adhered to the surface of the toner particles, but they are fixed by a mechanical mixing treatment such as a Henschel mixer or a hybridizer, or after being fixed, they are fused by heating. preferable. By such a mechanical mixing treatment, the charge control agent is fixed to the surface of the toner particles, and the impaction of the charge control agent on the carrier and the photoconductor is expected to be eliminated, and the preferable effect of the present invention is exhibited. Here, “fixed” means that the transfer rate of the charge control agent to the carrier after the toner and the carrier are shaken for 1 hour in a Turbula mixer is 1% or less.

In the present invention, as the toner to which the charge control resin and the charge control agent are added, known toners containing a binder resin and a colorant as essential components can be used.

Examples of the binder resin include styrenes such as styrene, chlorostyrene and vinyl styrene; monoolefins such as ethylene, propylene, butylene and isoprene; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate and vinyl butyrate. Methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate,
Octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate,
Α-Methylene aliphatic monocarboxylic acid esters such as dodecyl methacrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl butyl ether; homopolymers of vinyl ketone such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropenyl ketone. Alternatively, a copolymer can be exemplified, and as a typical binder resin, polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer,
Examples thereof include styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyethylene and polypropylene. In addition, polyester, polyurethane,
Examples thereof include epoxy resin, silicone resin, polyamide, modified rosin, and paraffins.

Further, as the colorant for the toner, carbon black, magnetic powder, dyes and pigments such as nigrosine dye, aniline blue, calcoil blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow and methylene blue chloride are used. , Phthalocyanine blue, malachite green oxalate,
Lamp Black, Rose Bengal, C.I. I. Pigment Red 48: 1, C.I. I. Pigment Red 12
2, C.I. I. Pigment Red 57: 1, C.I. I. Pigment Yellow 97, C.I. I. Pigment Yellow 12, C.I. I. Pigment Blue 15: 1, C.I.
I. Pigment Blue 15: 3 and the like can be illustrated as a typical example.

Further, the toner of the present invention has, if desired, a hydrophobized SiO ₂ , TiO ₂ , MgO or Al ₂ O ₃ such as hexamethyldisilazane, dimethyldichlorosilane and octyltrimethoxysilane. , Mn
_{O, ZnO, Fe 2 O 3} , Ca0, BaSO 4, CeO
₂ , K ₂ O, Na ₂ O, ZrO ₂ , CaO · SiO, K
Inorganic oxide fine particles such as ₂ O (TiO ₂ ) n and Al ₂ O ₃ .2SiO ₂ may be added as a flow promoter, and further known additives such as a release agent and a cleaning aid may be contained. Good.

The toner in the present invention may be a magnetic one-component toner containing a magnetic material or a capsule toner. In the present invention, the toner average particle diameter is 30 μm.
In the following, it is particularly preferable to set in the range of 3 to 20 μm.

When the toner of the present invention is used as a two-component developer, the carrier used is not particularly limited as long as it is a known carrier, and it is an iron powder type carrier, a ferrite type carrier or a surface coated ferrite. A system carrier, a magnetic powder dispersion type carrier or the like can be used.

The toner of the present invention can be appropriately used depending on the dry process, but in general, an electrostatic latent image is formed on an electrostatic latent image carrier such as electrophotography and electrostatic recording. After that, it can be used in the process of visualizing the electrostatic latent image by the developer in the developing machine, transferring the visible image to another carrier, and then cleaning the toner remaining on the electrostatic latent image carrier. ..

As the electrostatic latent image bearing member, a Se type photosensitive member,
Conventionally known organic photoconductors, amorphous silicon photoconductors, or those whose surface is overcoated if necessary can be used. Further, as the developing machine, all known ones such as a conventional two-component developing machine and a one-component developing machine can be used. Further, as the cleaning means, a cleaning method by blade pressure bonding, a fur brush cleaning method, or any other known method can be used.

[0023]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the following explanation,
"Part" represents "part by weight".

Example 1 Binder resin (styrene-butyl acrylate copolymer) 100 parts Positive charge control resin of the following formula (III) (Mw = 7.0 × 10 ³ , 3 parts Mn = 3.5 × 10) ³ k ': l': m '= 90: 7: 3) Carbon black (R330 Cabot Co., Ltd.) 10 parts Low molecular weight polypropylene (Viscor 660P Sanyo Chemical Co., Ltd.) 5 parts

[0025]

[Chemical 3]

The above components were kneaded with a Banbury mixer, pulverized and classified to prepare toner particles having an average particle diameter of 11 μm. To 100 parts of the toner particles, 1 is added a positive charge control agent (Bontron P-51 manufactured by Orient Chemical Industry Co., Ltd.).
Part of the mixture was added to a V-type blender, and the mixture was stirred at a rotation number of 40 rpm for 20 minutes to adhere to the surface of the toner particles. Further, 2 parts of titanium dioxide fine powder was added to 100 parts of the toner particles and dispersed and mixed by a V-type blender to obtain a toner. Next, 4 parts of vinylidene fluoride-hexafluoropropylene copolymer was dissolved in 100 parts of dimethylformamide to prepare a coating solution, and 500 parts of spherical iron oxide powder having an average particle diameter of 100 μm was flowed in a fluidized bed coating apparatus. The solution for coating was sprayed and the solvent was removed to obtain a carrier. A developer composition was prepared by mixing 5 parts of the toner and 95 parts of the carrier.

Example 2 Using a Henschel mixer, the peripheral speed of the charge control agent was 40 m /
A developer composition was obtained in the same manner as in Example 1 except that the toner particles were fixed on the surfaces of the toner particles for 15 minutes under the condition of sec.

Example 3 After the charge control agent was fixed on the surface of the toner particles in the same manner as in Example 2, a fluidized bed dryer (manufactured by Okawara Seisakusho Co., Ltd.) was used and the charge control agent was heated in a gas phase heated to 110 ° C. Except for heating for a minute and fusing the toner surface by locally melting it,
A developer composition was obtained in the same manner as in Example 1.

Example 4 Binder resin (styrene-butyl acrylate copolymer) 100 parts Negative charge control resin (Mw = 7.0 × 10 ³ ) of the following formula (IV) 3 parts (y ′: z ′ =) 95: 5) Carbon black (BP1300 manufactured by Cabot) 10 parts Low molecular weight polypropylene (Viscor 660P manufactured by Sanyo Kasei) 5 parts

[0030]

[Chemical 4]

The above components were kneaded in a Banbury mixer, pulverized and classified to prepare toner particles having an average particle diameter of 11 μm. To 100 parts of the toner particles, 1 part of a charge control agent (Spilon Black TRH, Hodogaya Chemical Co., Ltd.) was added and put in a V-type blender, and stirred at a rotation speed of 40 rpm for 20 minutes to adhere to the toner particle surface. It was further,
2 parts of fine silica powder was added to 100 parts of the toner particles,
A V type blender was used for dispersion and mixing to obtain a toner. Next, 0.8% by weight of a methyl methacrylate polymer (Mw = based on spherical iron oxide powder having an average particle diameter of 85 μm)
8.5 × 10 ⁴ ) was added, and coating was performed using a fluidized bed coating device so that the film thickness was about 1.2 μm to obtain a carrier. A developer composition was prepared by mixing 5 parts of the toner and 95 parts of the carrier.

Example 5 Using a Henschel mixer, the peripheral speed of 40 m /
A developer composition was obtained in the same manner as in Example 4, except that the toner particles were fixed on the surfaces of the toner particles for 15 minutes under the condition of sec. The developer was shaken in a Turbula mixer for 1 hour, and the toner was separated by a carrier by blow-off and collected. In addition, the carrier is at 0.
Chromium was quantified by fluorescent X-rays for each of the toner and the carrier collected as described above, which was rinsed out with a 5% Triton solution, and was not detected in the carrier, and 99.8% was detected in the toner. Was done.

Example 6 After the charge control agent was fixed on the surface of the toner particles in the same manner as in Example 5, a fluidized bed dryer (manufactured by Okawara Seisakusho) was used in a gas phase heated near the toner Tg. A developer composition was obtained in the same manner as in Example 4, except that the toner surface was locally melted by heating for 3 minutes to fuse the toner.

Comparative Example 1 A developer composition was obtained in the same manner as in Example 1 except that the charge control agent was not added externally.

Comparative Example 2 Binder resin (styrene-butyl acrylate copolymer) 100 parts Charge control agent (Bontron P-51 manufactured by Orient Chemical Co., Ltd.) 2 parts Carbon black (manufactured by R330 Cabot Co.) 10 parts Low molecular weight polypropylene (Viscole 660P, manufactured by Sanyo Kasei Co., Ltd.) 5 parts A developer composition was obtained in the same manner as in Example 1 except that the toner composition was as described above and the charge control agent was not added externally.

Comparative Example 3 Binder resin (styrene-butyl acrylate copolymer) 100 parts Carbon black (R330 Cabot Co.) 10 parts Low molecular weight polypropylene (Viscor 660P Sanyo Chemical Co., Ltd.) 5 parts Toner composition as above A developer composition was obtained in the same manner as in Example 1 except that

Comparative Example 4 Binder resin (styrene-butyl acrylate copolymer) 100 parts Charge control agent (Bontron P-51 manufactured by Orient Chemical Industry Co., Ltd.) 2 parts Carbon black (manufactured by R330 Cabot Co.) 10 parts Low molecular weight polypropylene (Viscole 660P, manufactured by Sanyo Kasei Co., Ltd.) 5 parts A developer composition was obtained in the same manner as in Example 1 except that the toner composition was changed as described above.

Comparative Example 5 As in Example 1, except that the charge control resin and 1 part of the charge control agent (Bontron P-51 Orient Chemical Co., Ltd.) were added internally and the charge control agent was not added externally. A developer composition was obtained in the same manner.

Comparative Example 6 A developer composition was obtained in the same manner as in Example 1 except that the charge control agent was not added externally.

Comparative Example 7 Binder resin (styrene-butyl acrylate copolymer) 100 parts Charge control agent (Spiron Black TRH Hodogaya Chemical Co., Ltd.) 2 parts Carbon black (BP1300 Cabot Co.) 10 parts Low molecular weight polypropylene (Viscole 660P, manufactured by Sanyo Kasei Co., Ltd.) 5 parts A developer composition was obtained in the same manner as in Example 4 except that the toner composition was as described above and the charge control agent was not added externally.

Comparative Example 8 Binder resin (styrene-butyl acrylate copolymer) 100 parts Carbon black (BP1300 manufactured by Cabot) 10 parts Low molecular weight polypropylene (Viscole 660P manufactured by Sanyo Kasei Co., Ltd.) 5 parts Toner composition as described above A developer composition was obtained in the same manner as in Example 5, except that

Comparative Example 9 Binder resin (styrene-butyl acrylate copolymer) 100 parts Charge control agent (Spiron Black TRH Hodogaya Chemical Co., Ltd.) 2 parts Carbon black (BP1300 Cabot Co.) 10 parts Low molecular weight polypropylene (Viscole 660P, manufactured by Sanyo Kasei Co., Ltd.) 5 parts A developer composition was obtained in the same manner as in Example 5 except that the toner composition was changed as described above.

Comparative Example 10 The procedure of Example 4 was repeated except that the charge control resin and 1 part of the charge control agent (Spiron Black TRH, Hodogaya Chemical Co., Ltd.) were added internally and the charge control agent was not added externally. A developer composition was obtained in the same manner as in Example 4.

Table 1 shows the addition states of the charge control components of these developer compositions, and Table 2 shows the test results obtained using the developer compositions.

[0045]

[Table 1]

[0046]

[Table 2] * 1: Each measurement was performed after blending for 30 minutes in a normal environment using a V blender. * 2: Examples 1 to 3 and Comparative Examples 1 to 5 are Vivace 500 manufactured by Fuji Xerox, Examples 4 to 6, and Comparative Examples 6 to.
For No. 10, after making 50,000 copies with Fuji Xerox FX-5990, each measurement was performed. * 3: The amount of charge was measured using a probe-off measuring device. * 4: The solid density and background density were measured using a Macbeth densitometer. * 5: Charge distribution is measured by Charge spec
It was carried out based on the results using a ra graph measuring device. * 6: TC latitude is expressed by the following equation. TC (L) = TC (high) -TC (low) TC (high): The upper limit TC at which fog does not occur. TC (low): Concentration measured by Macbeth densitometer 1.
I copied 0 solid patch. Lower limit T at which the sample exhibits a concentration of 1.1 or higher measured by a Macbeth densitometer.
C. ** Not suitable for ADC (automatic density adjustment function). (The image density does not rise because the density does not follow this function.)

[047]

In the dry toner for developing an electrostatic image of the present invention, since the charge control resin is contained in the toner particles, the dispersibility in the toner particles is improved and the internal charge control component between the toner particles is improved. The existence variation of is eliminated. Also,
Since the charge control agent is externally added, variations in the charge control component on the surface layer of the toner particles are also reduced. Therefore, the dry toner for developing an electrostatic charge image of the present invention has a narrow charge distribution, and can achieve both high chargeability, good charge maintainability, and good charge exchangeability. In addition, the charge control agent added from the outside is not attached electrostatically, but is fixed to the toner particle surface by mechanical force such as a Henschel mixer, a hybridizer, etc. The impaction of is eliminated.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takayoshi Aoki 1600 Takematsu, Minamiashigara City, Kanagawa Prefecture Fuji Zero Tux Co., Ltd. Takematsu Office

Claims (1)

[Claims] 1. A dry toner for developing an electrostatic charge image, which comprises at least a binder resin and a colorant as essential components,
A dry toner for developing electrostatic images, characterized in that a charge control resin is internally added to toner particles, and a charge control agent is externally added and contained.