JPH0594037A - Electrophotographic developer - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic developer having stable electrifying property and excellent in fluidity. CONSTITUTION:A hydrophobic silica powder which is treated by an amino substituted silane compound shown in the expression and organopolysiloxane, of which frictional electrification quantity to iron is in a region of 100-(-100)muC/g and ratio of hydrophobicity determined by transmission factor method is >=60% is added to a toner. In this expression, R<1> is an amino substituted alkyl group having 1-10 carbon number; R<2> is an alkyl group having 1-5 carbon number; R<3> is Cl, Br or alkoxy group having 1-5 carbon number; and (n) is an integer of 1-3.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a developer used in electrophotography and electronic recording.

[0002]

2. Description of the Related Art Additives (fluidity improvers) have been widely used in electrophotographic developer toners for the purpose of increasing fluidity and preventing aggregation. Conventionally, a metal oxide fine powder having a hydrophobic surface, particularly silica powder, has been generally used as a fluidity improver. However, in view of the triboelectric chargeability with iron (iron oxide) which is generally used as a carrier, these additives themselves have high chargeability. Therefore, the influence on the chargeability of the toner itself becomes remarkable, and the development such that the dependency of the charge amount on the humidity and the temperature is increased or the stability with time is decreased occurs. Therefore, the amount of these additives used is generally 1 part by weight or less, and the resulting improvement in fluidity is not always sufficient.

[0003]

SUMMARY OF THE INVENTION In consideration of the above-mentioned problems of the prior art, an object of the present invention is to use an additive having a small effect on the chargeability of the toner itself and having a sufficient fluidity improving effect.
An object is to provide an electrophotographic developer having stable chargeability and excellent fluidity. The inventors of the present invention have conducted extensive studies to achieve the above object. The surface treatment is performed by combining an appropriate amount of an amino-substituted silane compound and an organopolysiloxane, and the absolute value of the triboelectric charge amount with respect to iron is the same as the conventional hydrophobicity. It has been found that silica, which is smaller than silica and has a high degree of hydrophobicity, is suitable for the above purpose. That is, when this surface-treated silica is added to the toner, the change in the amount of charge of the toner itself is extremely small, so that even if used in a relatively large amount, sufficient fluidity can be obtained without impairing the characteristics of the toner, and the humidity can be improved. The object of the present invention was achieved by confirming that the image is less likely to be affected by the temperature and the temperature, and further less likely to cause the fog and the image deterioration.

[0004]

According to the present invention, an amino-substituted silane compound and an organopolysiloxane are used for treatment, and the triboelectrification amount for iron is 100 μC / g to −100 μC / g, preferably 50 μC / g.
In the range of μC / g to −50 μC / g, and the hydrophobicity measured by the transmittance method is 60% or more, preferably a silica powder showing a value of 70% or more is added to the toner, A developer for electrophotography is provided.

The amino-substituted silane compound used in the present invention is represented by the general formula (1) R ¹ SiR ² _3-n R ³ _n [wherein each R ¹ is an amino-substituted alkyl group having 1 to 10 carbon atoms; R2 is an alkyl group having 1 to 5 carbon atoms; R3 is C
l, Br or an alkoxy group having 1 to 5 carbon atoms; n is 1 to
Represents an integer of 3. ] The compound shown below is illustrated. _{H 2 N (CH 2) 3} Si (OEt) 3 H 2 N (CH 2) 2 NH (CH 2) 3 Si (OMe) 3 H 2 N (CH 2) 2 NH (CH 2) 3 SiMe (OMe) ₂ C ₆ H ₅ HN (CH ₂ ) ₃ Si (OMe) ₃ H ₂ N (CH ₂ ) ₂ NH (CH ₂ ) ₃ SiCl ₃ The organopolysiloxane used in the present invention adheres uniformly to the silica powder surface. It is not particularly limited except that it has a certain degree of fluidity, but from the viewpoint of processing operation, 10cs to 1000cs
It is preferable to use one having a viscosity of a certain degree. In addition, from the viewpoint of hydrophobicity and availability,-(SiR ⁴ R
⁵ O)-[wherein R ⁴ and R ⁵ represent the same or different substituents selected from an alkyl group, a phenyl group, a phenyl-substituted alkyl group, an alkoxy group and a hydrogen group (provided that R ⁴ and R ⁵ Is not simultaneously a hydrogen group)], and an organopolysiloxane having a repeating unit represented by The silica powder used in the present invention may have a particle size suitable for the application required for its charging characteristics, and particularly preferably has a specific surface area of 50 m ² / g or more.

The method for measuring the amount of triboelectricity with respect to iron is specified in the literature such as "Coloring Material" (55 [9] 630-636, 1982). It is practically desirable that the value is in the range of 100 μC / g to −100 μC / g, preferably 50 μC / g to −50 μC / g in order to suppress the influence on the charging property of the toner.

The transmittance method is a method for experimentally determining the hydrophobicity of the treated silica powder, and is measured by the following procedure. 1.0 g of the treated silica powder and 100 ml of water are placed in an extraction flask and shaken vigorously for 5 minutes. Then, it is allowed to stand for 1 minute, and a small amount of suspension is withdrawn from the bottom of the flask.
The transmittance of this liquid for 550 nm light is 1% for pure water.
The value expressed as 00% is the hydrophobicity of the silica. As the value of the hydrophobicity ratio thus measured is higher, the hygroscopicity of the silica powder is reduced, the change of the charge amount of the toner with respect to the humidity is reduced, and the effect of preventing aggregation is enhanced, and the utility value is high. However, in practice, it is desirable to have a value of 60% or more, preferably 70% or more.

As a method for treating the silica powder used in the present invention, a conventionally known method is applied. While the silica powder to be treated is mechanically stirred sufficiently, an amino-substituted silane compound and subsequently or simultaneously organopolysiloxane are added dropwise or sprayed thereto. At this time, it is preferable to add diethylamine or the like as a catalyst for enhancing the reactivity of the amino-substituted silane compound, or to blow in ammonia gas. It is also possible to use a solvent such as an alcohol, a ketone or a hydrocarbon as a diluent depending on the viscosity of the amino-substituted silane compound and the organopolysiloxane used. After the treating agent is added, the reaction is completed by heating at a temperature in the range of 100 ° C. to 250 ° C. under a nitrogen atmosphere to remove the solvent.

The hydrophobic silica used in the present invention, that is, the amount of triboelectrification against iron is in the range of 100 μC / g to −100 μC / g, and the hydrophobicity measured by the transmittance method is
The amount of the amino-substituted silane compound and organopolysiloxane used to obtain the silica powder characterized by exhibiting a value of 60% or more depends on the specific surface area of the silica to be treated and the type of the treating agent. Specifically, for example, the specific surface area 13
In the case of 0 m ² / g silica powder, the amount of amino-substituted silane compound used is 1.0 wt% to 4.0 wt% of the weight of silica to be treated.
It is sufficient if the amount of the organopolysiloxane used is about 3.0% by weight to about 8.0% by weight. Silica particles treated with the above amino-substituted silane compound and dimethylpolysiloxane are added to the toner by a usual method to prepare the developer of the present invention.

[0010]

The developer according to the present invention is treated with the amino-substituted silane compound and the organopolysiloxane as described above, and the triboelectric charge amount to iron is from 100 μC / g to −10.
The developer is characterized in that silica particles having a hydrophobicity of 60% or more as measured by a transmittance method in a range of 0 μC / g are added to the toner. Since the developer has a small triboelectrification property, the present developer is greatly improved in the stability of the charge amount of the toner against the environment and the stability over time, and as a result, the effect of suppressing the occurrence of fog and the deterioration of image quality is achieved. can get. Further, the amount of silica particles added can be increased as compared with conventional additives, and as a result, excellent fluidity can be obtained. Hereinafter, the present invention will be specifically described with reference to examples.

[0011]

Example 1 Heat-dried silica (specific surface area 130 m ² / g) 2
0 g was placed in a stainless steel container, and a treating agent having the following composition was sprayed onto the silica at room temperature while stirring under a nitrogen atmosphere. Treatment agent Amino-substituted silane compound H ₂ N (CH ₂ ) ₃ Si (OEt) ₃ 0.36 g Dimethyl polysiloxane Shin-Etsu Chemical Co., Ltd. KF-96 (50cs) 1.00 g Diethylamine few drops n-Propanol 5.0 ml After stirring for 30 minutes at 70 ° C., external heating was performed under a nitrogen stream, the temperature was raised to 150 ° C. over 40 minutes, the temperature was maintained for 30 minutes, and then the mixture was allowed to cool to room temperature. The hydrophobicity of the obtained powder (Powder-1) by the transmittance method and the triboelectric charge with respect to iron were 83% and -27 µC / g, respectively. Next, disperse 18% carbon in styrene-acrylic resin,
After crushing, resin powder (resin powder-
1) Toner was prepared by mixing 1 g of the above silica particles in 100 g. Furthermore, 30 g of this toner is added to 1000 g of iron oxide powder.
In addition, a developer was used. The triboelectric charge of this developer is -15
It was μC / g. When this developer was put in a commercially available copying machine and subjected to a life test, no fog occurred on the image even after copying about 20,000 sheets. Higher temperature and humidity (28
A good image was shown even under the environment of ℃ and 85% RH. The triboelectric charge amount of the developer prepared without adding silica particles was also -15 μC / g.

[0012]

Example 2 A developer was prepared in the same manner as in Example 1 except that the amount of the silica powder (powder-1) obtained in Example 1 was changed from 1 g to 2 g. The charge amount of this developer was −16 μC / g. When this developer was put into a commercially available copying machine and a life test was conducted, no fog occurred on the image even after copying about 28,000 sheets. Furthermore, it showed good performance even under the environment of high temperature and high humidity (28 ℃, 85% RH).

[0013]

Example 3 Carbon 18 in styrene-acrylic resin
%, Nigrosine 5%, dispersed and pulverized, and then classified into 10 μ to 20 μ (resin powder-2), which was used in place of (resin powder-1) in Example 1 Then, a developer was prepared. The charge amount of this developer was +18 μC / g. When this developer was put in a commercial copying machine and a life test was performed,
Fogging did not occur in the image even when copying about 25,000 sheets or more. Furthermore, it showed good performance even under the environment of high temperature and high humidity (28 ℃, 85% RH).

[0014]

Example 4 Heat-dried silica (specific surface area 130 m ² / g) 2
0 g was placed in a stainless steel container, and a treating agent having the following composition was sprayed onto the silica at room temperature while stirring under a nitrogen atmosphere. Treatment agent Amino-substituted silane compound H ₂ N (CH ₂ ) ₂ NH (CH ₂ ) ₃ Si (OMe) ₃ 0.30 g Dimethylpolysiloxane Shin-Etsu Chemical Co. KF-96 (50cs) 1.50 g Diethylamine A few drops of acetone 5.0 ml After spraying, further stir at room temperature for 30 minutes, then heat externally under a nitrogen stream to raise the temperature to 150 ° C over 40 minutes, hold at this temperature for 30 minutes, and then allow to cool to room temperature. did. The hydrophobicity of the obtained powder by the transmittance method and the triboelectric charge on iron were 95% and +23 μC / g, respectively. Next, Example 1
A toner was prepared by mixing 0.5 g of the above silica particles with 100 g of (resin powder-1), and 30 g of this toner was added to 1000 g of iron oxide powder to obtain a developer. The triboelectric charge of this developer was -15 μC / g. When this developer was put into a commercially available copying machine and a life test was conducted, no fog occurred on the image even after copying about 28,000 sheets. Furthermore, it showed good performance even under the environment of high temperature and high humidity (28 ℃, 85% RH).

[0015]

Example 5 A developer was prepared in the same manner as in Example 4 except that (resin powder-1) in Example 1 was replaced with (resin powder-2) in Example 3. The charge amount of this developer was +17 μC / g.
When this developer was put into a commercially available copying machine and a life test was conducted, no fog occurred on the image even after copying about 34,000 sheets. Furthermore, it showed a good image even under the environment of high temperature and high humidity (28 ℃, 85% RH).

[0016]

Example 6 Heat-dried silica (specific surface area 130 m ² / g) 2
0 g was placed in a stainless steel container, and a treating agent having the following composition was sprayed onto the silica at room temperature while stirring under a nitrogen atmosphere. Treatment agent Amino-substituted silane compound H ₂ N (CH ₂ ) ₂ NH (CH ₂ ) ₃ Si (OMe) ₃ 0.41 g Methyl human chloropolysiloxane Shin-Etsu Chemical Co. KF-99 (20cs) 1.00 g Diethylamine A few drops of n-Propanol 5.0 ml After spraying, stir at room temperature for 30 minutes, then heat externally under a nitrogen stream to raise the temperature to 150 ° C over 40 minutes, hold at this temperature for 30 minutes, and then reach room temperature. I let it cool. The hydrophobicity of the obtained powder by the transmittance method and the amount of triboelectricity with respect to iron were 91% and -8 μC / g, respectively. Next, Example 1
A toner was prepared by mixing 0.5 g of the above silica particles with 100 g of (resin powder-1), and 30 g of this toner was added to 1000 g of iron oxide powder to obtain a developer. The triboelectric charge of this developer was -15 μC / g. When this developer was put into a commercially available copying machine and a life test was conducted, no fog occurred in the image even after copying about 24,000 sheets. Furthermore, it showed good performance even under the environment of high temperature and high humidity (28 ℃, 85% RH).

[0017]

Example 7 A developer was prepared in the same manner as in Example 6 except that (resin powder-1) in Example 1 was replaced with (resin powder-2) in Example 3. The charge amount of this developer was +18 μC / g.
When this developer was put into a commercially available copying machine and subjected to a life test, no fog occurred on the image even after copying about 23,000 sheets. Furthermore, it showed a good image even under the environment of high temperature and high humidity (28 ℃, 85% RH).

[0018]

Example 8 Heat-dried silica (specific surface area 130 m ² / g) 2
0 g was placed in a stainless steel container, and a treating agent having the following composition was sprayed onto the silica at room temperature while stirring under a nitrogen atmosphere. Treatment agent Amino-substituted silane compounds _{C 6 H 5 NH (CH 2} ) 3 Si (OMe) 3 0.30g methylalkoxy Ho ° polysiloxane manufactured by Shin-Etsu Chemical Co. KF-851 (80cs) 0.95g Shi Bu ethylamine A few drops of n-Propanol 5.0 ml After spraying, stir at room temperature for 30 minutes, then heat externally under a nitrogen stream to raise the temperature to 150 ° C over 40 minutes, hold at this temperature for 30 minutes, and then reach room temperature. I let it cool. The hydrophobicity of the obtained powder by the transmittance method and the amount of triboelectricity with respect to iron were 88% and +11 μC / g, respectively. Next, Example 1
A toner was prepared by mixing 0.5 g of the above silica particles with 100 g of (resin powder-1), and 30 g of this toner was added to 1000 g of iron oxide powder to obtain a developer. The triboelectric charge of this developer was -15 μC / g. When this developer was put into a commercially available copying machine and subjected to a life test, no fog occurred on the image even after copying about 21,000 sheets. Furthermore, it showed good performance even under the environment of high temperature and high humidity (28 ℃, 85% RH).

[0019]

Example 9 A developer was prepared in the same manner as in Example 8 except that (resin powder-1) in Example 1 was replaced with (resin powder-2) in Example 3. The charge amount of this developer was +18 μC / g.
When this developer was put in a commercially available copying machine and subjected to a life test, no fog occurred on the image even after copying about 20,000 sheets. Furthermore, it showed a good image even under the environment of high temperature and high humidity (28 ℃, 85% RH).

[0020]

Example 10 Heat-dried silica (specific surface area 130 m ² /
g) 20 g was placed in a stainless steel container, and a treating agent having the following composition was sprayed onto the silica at room temperature while stirring under a nitrogen atmosphere. Treatment agent Amino-substituted silane compound H ₂ N (CH ₂ ) ₂ NH (CH ₂ ) ₃ Si (OMe) ₃ 0.40 g Methylstyrylpolysiloxane Shin-Etsu Chemical KF-410 (1000cs) 1.20 g Diethylamine A few drops of n-Propanol 5.0 ml After spraying, stir at room temperature for 30 minutes, then heat externally under a nitrogen stream to raise the temperature to 150 ° C over 40 minutes, hold at this temperature for 30 minutes, and then reach room temperature. I let it cool. The hydrophobicity of the obtained powder by the transmittance method and the amount of triboelectricity with respect to iron were 87% and -24 μC / g, respectively. Next, Example 1
A toner was prepared by mixing 0.5 g of the above silica particles with 100 g of (resin powder-1), and 30 g of this toner was added to 1000 g of iron oxide powder to obtain a developer. The triboelectric charge of this developer was -16 μC / g. When this developer was put into a commercially available copying machine and subjected to a life test, no fog occurred on the image even after copying about 25,000 sheets. Furthermore, it showed good performance even under the environment of high temperature and high humidity (28 ℃, 85% RH).

[0021]

Example 11 A developer was prepared in the same manner as in Example 10 except that (resin powder-1) in Example 1 was replaced with (resin powder-2) in Example 3. The charge amount of this developer was +18 μC / g. When this developer was put into a commercially available copying machine and subjected to a life test, no fog occurred on the image even after copying about 26,000 sheets. Furthermore, it showed a good image even under the environment of high temperature and high humidity (28 ℃, 85% RH).

[0022]

Example 12 Heat-dried silica (specific surface area 130 m ² /
g) 20 g was placed in a stainless steel container, and a treating agent having the following composition was sprayed onto the silica at room temperature while stirring under a nitrogen atmosphere. Treatment agent Amino-substituted silane compound H ₂ N (CH ₂ ) ₂ NH (CH ₂ ) ₃ Si (OEt) ₃ 0.38 g Methyl human chloropolysiloxane Shin-Etsu Chemical Co. KF-99 (20cs) 1.10 g Diethylamine A few drops of n-Propanol 5.0 ml After spraying, stir at room temperature for 30 minutes, then heat externally under a nitrogen stream to raise the temperature to 150 ° C over 40 minutes, hold at this temperature for 30 minutes, and then reach room temperature. I let it cool. The hydrophobicity of the obtained powder by the transmittance method and the amount of triboelectricity with respect to iron were 95% and +5 μC / g, respectively. Next, Example 1
A toner was prepared by mixing 0.5 g of the above silica particles with 100 g of (resin powder-1), and 30 g of this toner was added to 1000 g of iron oxide powder to obtain a developer. The triboelectric charge of this developer was -16 μC / g. When this developer was put into a commercially available copying machine and a life test was conducted, no fog occurred on the image even after copying about 28,000 sheets. Furthermore, it showed good performance even under the environment of high temperature and high humidity (28 ℃, 85% RH).

[0023]

Example 13 A developer was prepared in the same manner as in Example 12 except that (resin powder-1) in Example 1 was replaced with (resin powder-2) in Example 3. The charge amount of this developer was +18 μC / g. When this developer was put into a commercially available copying machine and subjected to a life test, no fog occurred on the image even after copying about 27,000 sheets. Furthermore, it showed a good image even under the environment of high temperature and high humidity (28 ℃, 85% RH).

[0024]

Comparative Example 1 Heat-dried silica (specific surface area 130 m ² / g) 2
0 g was placed in a stainless steel container, and a treating agent having the following composition was sprayed onto the silica at room temperature while stirring under a nitrogen atmosphere. Treatment agent Amino-substituted silane compound H ₂ N (CH ₂ ) ₃ Si (OEt) ₃ 0.40 g Diethylamine A few drops of n-Propanol 5.0 ml After spraying, stir at room temperature for 30 minutes, then heat externally under a nitrogen stream to raise the temperature to 150 ° C over 40 minutes, hold at this temperature for 30 minutes, and then reach room temperature. I let it cool. The hydrophobicity of the obtained powder by the transmittance method and the amount of triboelectrification on iron were 41% and +15 μC / g, respectively. Next, Example 1
A toner was prepared by mixing 0.5 g of the above silica particles with 100 g of (resin powder-1), and 30 g of this toner was added to 1000 g of iron oxide powder to obtain a developer. The triboelectric charge of this developer was -14 μC / g. When this developer was put in a commercially available copying machine and a life test was conducted, fog was generated on the image in about 14,000 copies or more. Furthermore, in the environment of high temperature and high humidity (28 ℃, 85% RH), a clear image deterioration was shown.

[0025]

Comparative Example 2 A developer was prepared in the same manner as in Comparative Example 1 except that (resin powder-1) in Example 1 was replaced with (resin powder-2) in Example 3. The charge amount of this developer was +18 μC / g.
When this developer was put in a commercially available copying machine and a life test was conducted, fog was generated on the image in about 15,000 or more copies. Furthermore, in the environment of high temperature and high humidity (28 ℃, 85% RH), a clear image deterioration was shown.

[0026]

[Comparative Example 3] Heat-dried silica (specific surface area: 130 m ² / g) 2
0 g was placed in a stainless steel container, and a treating agent having the following composition was sprayed onto the silica at room temperature while stirring under a nitrogen atmosphere. Treatment agent Methyl human chloropolysiloxane Shin-Etsu Chemical Co., Ltd. KF-99 (20cs) 1.10g n-Propanol 5.0ml After spraying is complete, after stirring for 30 minutes at room temperature, external heating is performed under a nitrogen stream for 150 minutes at 40 ° C. The temperature was raised to, held at this temperature for 30 minutes, and then allowed to cool to room temperature. The hydrophobicity of the obtained powder by the transmittance method and the amount of triboelectricity with respect to iron were 92% and -158 µC / g, respectively. Next, Example 1
A toner was prepared by mixing 0.5 g of the above silica particles with 100 g of (resin powder-1), and 30 g of this toner was added to 1000 g of iron oxide powder to obtain a developer. The triboelectric charge of this developer was -16 μC / g. When this developer was put in a commercially available copying machine and a life test was conducted, fog was generated on the image in about 14,000 copies or more. Furthermore, in the environment of high temperature and high humidity (28 ℃, 85% RH), a clear image deterioration was shown.

[0027]

Comparative Example 4 A developer was prepared in the same manner as in Comparative Example 3 except that (Resin powder-1) in Example 1 was replaced with (Resin powder-2) in Example 3. The charge amount of this developer was +16 μC / g.
When this developer was put into a commercially available copying machine and a life test was conducted, fog was generated on the image in about 10,000 or more copies. Furthermore, in the environment of high temperature and high humidity (28 ℃, 85% RH), a clear image deterioration was shown.

Claims (3)

[Claims] 1. Treated with an amino-substituted silane compound represented by the general formula (1) and an organopolysiloxane, the amount of triboelectricity with respect to iron is in the range of 100 μC / g to −100 μC / g, and measured by the transmittance method. The hydrophobized rate is 60%
A developer for electrophotography, comprising a silica powder having the above values added to a toner. General formula (1) R ¹ SiR ² _3-n R ³ _n [wherein each R ¹ is an amino-substituted alkyl group having 1 to 10 carbon atoms; R ² is an alkyl group having 1 to 5 carbon atoms; R ³ is C
l, Br or an alkoxy group having 1 to 5 carbon atoms; n represents an integer of 1 to 3. ] 2. The specific surface area of the treated silica is at least 50.
The developer for electrophotography according to claim 1, wherein the developer is m ² / g or more. 3. The organopolysiloxane is-(SiR ⁴ R
⁵ O)-[wherein R ⁴ and R ⁵ represent the same or different substituents selected from an alkyl group, a phenyl group, a phenyl-substituted alkyl group, an alkoxy group and a hydrogen group (provided that R ⁴ and R ⁵ Have no repeating units).] The electrophotographic developer according to claim 1 or 2, having a repeating unit represented by the formula: