JP2010237689A - Negative charging electrophotographic toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a negative charging toner having a high charge amount and showing fast rising on charging and high environmental stability. <P>SOLUTION: The toner includes a 2:1-type iron complex compound expressed by a general formula (1) as a charge controlling agent by α mass%. A monoazo compound as ligand included as impurity by β mass% in the iron complex compound is manufactured by setting and managing the compound to be α×β≤10. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a toner for developing an electrostatic image in an image forming method such as electrophotography and electrostatic recording.

Development methods applied to electrophotography and the like are roughly classified into a dry development method and a wet development method. The former is further divided into a method using a two-component developer and a method using a one-component developer.
As toners that can be used in these development methods, fine powders in which dyes or pigments are dispersed in natural or synthetic resins are conventionally used. For example, particles obtained by finely pulverizing a colorant dispersed in a binder resin such as polystyrene to about 5 to 15 μm are used as toner. As the magnetic toner, a toner containing magnetic particles such as magnetite is used.

  Any toner must have a positive or negative charge depending on the polarity of the latent electrostatic image to be developed. In order to retain the charge of the toner, the triboelectric chargeability of the resin, which is a component of the toner, can be used, but with this method sufficient developability such as fogging of the resulting image and reduction in image density due to insufficient charging. May not be obtained. Therefore, a charge control agent is added to impart desired triboelectric chargeability to the toner.

  The toner containing the charge control agent has different charging characteristics depending on the combination of the type of binder resin and the type of charge control agent. Among such charge control agents, it is known to use a monoazo metal complex compound. However, these charge control agents have a drawback that the quality of the initial copy image is likely to fluctuate due to insufficient affinity of the toner for the binder resin and the effect of imparting frictional charge. Further, it is easily affected by temperature and humidity, and has a drawback that the amount of charge is reduced in an environment with high humidity. Some monoazochrome complex compounds have solved these problems, but the possibility of producing very small amounts of harmful hexavalent chromium at the time of combustion and disposal cannot be completely denied, and this is given to the environment and the human body. There are concerns about the impact. Therefore, a charge control agent that uses a safer metal and is sufficiently satisfactory in terms of performance has been desired.

Several monoazo iron complex compounds having good performance are disclosed (for example, refer to Patent Document 1). However, since all those having good performance are azo complexes having a plurality of nitro groups, the compound is synthesized during synthesis. There is a risk of fire and explosion. In particular, when the central metal is iron, there is a significant risk of ignition and explosion, and the drying and pulverization processes are extremely dangerous operations. In addition, since the pulverized toner is generally kneaded by an extrusion kneader and pulverized and manufactured, there is a great possibility of powder explosion at the time of toner production. When chromium is used as the central metal, the risk of ignition / explosion is lower than that of iron, but the monoazochrome complex salt compound having a nitro group obtained in this case is also a self-reactive substance (Class 5 dangerous substance). Applicable and subject to restrictions.
A toner using a monoazo iron complex salt compound in which the central metal is iron is disclosed as a charge control agent (see, for example, Patent Document 2), and is practical as a negatively chargeable charge control agent that does not use chromium as the central metal. Some have a charge amount.

Japanese National Patent Publication No. 8-50092 JP 61-155464 A

  In recent years, printers and copiers that apply electrophotography have become widespread, and the speed of printing has been increasing year by year. Toners that maintain a proper charge instantaneously (good charge rise) are required compared to conventional copiers. It has come to be. That is, it is required more than a conventional toner for a toner containing an iron complex salt compound to maintain an appropriate charge instantly when the output state is entered from the rest state. The present invention provides a negatively chargeable electrophotographic toner which has a high charge amount, has a remarkably good charge rise, and can maintain a stable charge amount without being affected by temperature and humidity. The purpose is that.

  As a result of researches, the present inventors have found that a high charge amount can be obtained by using an iron complex salt compound and reducing the content of a specific intermediate compound in the iron complex salt compound to a certain range or less in the toner. The inventors have found that the rise of charge is remarkably good and that a stable charge amount is maintained without being affected by temperature and humidity. That is, the present invention provides the following general formula (1)

(Expressed in the formula, A, B are each independently a hydrogen source frame other is a halogen atom, X represents an alkyl group having a carbon number of 1 to 8, Y is substituted with an unsubstituted aromatic ring group or a halogen atom .J representing the aromatic ring group represents a hydrogen ion, an alkali metal ion, ammonium ion, or alkylammonium ions, these ions in J is represented by two or more may be mixed.) A toner containing α% by mass of a 2: 1 type iron complex salt compound as a charge control agent, wherein β mass% is contained as an impurity in the iron complex salt compound.

(Expressed in the formula, A, B are each independently a hydrogen source frame other is a halogen atom, X represents an alkyl group having a carbon number of 1 to 8, Y is substituted with an unsubstituted aromatic ring group or a halogen atom represents an aromatic ring group. represented by monoazo compound), in order to 1000ppm or less as content to the toner, and the content α in the toner of the charge control agent as 1 to 3 wt% a negatively chargeable electrophotographic toner characterized in that it is manufactured by setting management in α × β ≦ 10.

In the present invention, preferably the following general formula (3)

(Wherein, X represents an alkyl group having a carbon number of 1 to 8, C, D is hydrogen original frame other independently represents a halogen atom, J is hydrogen ion, alkali metal ions, ammonium ions or, A toner containing α% by mass of a 2: 1 type iron complex salt compound represented by the formula (1), wherein two or more of these ions may be mixed in J): The following general formula (4) contained in the iron complex compound as an impurity in an amount of β mass%.

1000 ppm (wherein, X represents an alkyl group having a carbon number of 1 to 8, C, D represent. Independently a hydrogen source frame other is a halogen atom) a monoazo compound represented by the content of the toner In order to achieve the following, negatively chargeable electrons produced by controlling the content α of the charge control agent in the toner to be 1 to 3% by mass and setting α × β ≦ 10 It is a photographic toner.

Another embodiment of the present invention is the following general formula (1).

(Expressed in the formula, A, B are each independently a hydrogen source frame other is a halogen atom, X represents an alkyl group having a carbon number of 1 to 8, Y is substituted with an unsubstituted aromatic ring group or a halogen atom .J representing the aromatic ring group represents a hydrogen ion, an alkali metal ion, ammonium ion, or alkylammonium ions, these ions in J is represented by two or more may be mixed.) A toner containing α% by mass of a 2: 1 type iron complex salt compound as a charge control agent, wherein β mass% is contained as an impurity in the iron complex salt compound.

(Expressed in the formula, A, B are each independently a hydrogen source frame other is a halogen atom, X represents an alkyl group having a carbon number of 1 to 8, Y is substituted with an unsubstituted aromatic ring group or a halogen atom represents an aromatic ring group. represented by monoazo compound), in order to 1000ppm or less as content to the toner, and the content α in the toner of the charge control agent as 1 to 3 wt% , and sets managed α × β ≦ 10, a negatively charged electrophotographic toner produced during impurity suppressed management method.

In another embodiment of the present invention, the following general formula (3) is preferable.

(Wherein, X represents an alkyl group having a carbon number of 1 to 8, C, D is hydrogen original frame other independently represents a halogen atom, J is hydrogen ion, alkali metal ions, ammonium ions or, A toner containing α% by mass of a 2: 1 type iron complex salt compound represented by the formula (1), wherein two or more of these ions may be mixed in J): The following general formula (4) contained in the iron complex compound as an impurity in an amount of β mass%.

1000 ppm (wherein, X represents an alkyl group having a carbon number of 1 to 8, C, D represent. Independently a hydrogen source frame other is a halogen atom) a monoazo compound represented by the content of the toner In order to achieve the following, a negatively chargeable electrophotographic toner characterized in that the content α of the charge control agent in the toner is 1 to 3% by mass and is set and managed as α × β ≦ 10 This is an impurity suppression management method during manufacturing.

Among the negatively chargeable electrophotographic toners of the present invention, those having excellent performance include those in the general formula (3) wherein X is a methyl group, C and D are hydrogen atoms, and X is methyl. And a group in which C is a hydrogen atom and D is a 4-chloro group, X is a methyl group, C is a 3-chloro group, and D is a 4-chloro group. In addition, in the case of these 2: 1 type iron complex salt compounds, the method can be satisfactorily applied also in the impurity suppression management method during the production of the negatively chargeable electrophotographic toner of the present invention.

The negatively chargeable electrophotographic toner of the present invention has a high amount of charge, has a fast charge start-up, and is environmentally stable because the specific impurity content is suppressed by the impurity suppression management method at the time of toner production. Are better. Further, in the negatively chargeable electrophotographic toner of the present invention, since the 2: 1 type iron complex salt compound in the toner does not have a nitro group in the structural formula, it does not cause powder explosion during toner production. In addition, since it does not contain metals such as chromium, there is no possibility of producing harmful substances even when it is burned or oxidized, so it is safe for the environment. It is also suitable as an impurity suppression management method during toner production.

In the impurity suppression management method during the production of the negatively chargeable electrophotographic toner of the present invention, the general formula (2) which is an impurity in the 2: 1 type iron complex salt compound represented by the general formula (1) in the first step. The monoazo compound content β represented by is analyzed. In the second stage, depending on the obtained β value, whether to proceed directly to the next toner production stage or whether to repurify the 2: 1 type iron complex salt compound represented by the general formula (1). decide. When the β value is large, the amount of 2: 1 type iron complex compound added to the toner manufactured in the third stage is limited. In the case of a toner with a low addition amount of the 2: 1 type iron complex salt compound, even if the β value is slightly large, it is possible to proceed directly to the third stage toner production. However, if the addition amount of the 2: 1 type iron complex salt compound in the toner is excessively reduced, the performance of the toner is impaired. When the β value is further increased, the 2: 1 type iron complex compound is purified again. In this way, by analyzing the β value in the first stage in advance, it is possible to reliably reduce the risk factor for producing poor quality toner. Conversely, it is possible to reliably reduce the burden of excessive purification. Furthermore, this means that the monoazo compound content β represented by the general formula (4), which is an impurity in the 2: 1 type iron complex salt compound represented by the general formula (3), is analyzed in the first stage. The same effect as described above can be obtained.

As a means for analyzing the monoazo compound content β represented by the general formula (2) or the general formula (4) in the first stage in the impurity suppression management method during the production of the negatively chargeable electrophotographic toner of the present invention, high-speed Liquid chromatography is suitable. Other gas chromatography methods can also be employed. Any of these is a means suitable as an impurity suppression management method at the time of compound production.

2: 1 type at the time of production in the 2: 1 type iron complex salt compound represented by the general formula (1) or general formula (3), and when the β value is large in the first stage and repurification is necessary. As a method for removing the monoazo compound represented by the general formula (2) or the general formula (4) which is an impurity in the iron complex salt compound, it is most suitable to use the difference in solubility. This is because the solubility of the monoazo compound in the solvent is relatively high.

As a method for removing the monoazo compound as an impurity, a method of washing with methanol, dimethylformamide (DMF) or the like, a method of recrystallization with methanol, DMF or the like, a solvent such as tetrahydrofuran (THF), DMF, or dimethylsulfoxide (DMSO) is used. As a method of dissolving and crystallizing using a low-solubility solvent such as cyclohexane, and a method of increasing the purity, there are a method of extracting using a polar solvent after separating on a column by chromatography, etc. Or it is possible by combining.

Examples are shown below, but are not limited thereto. In the examples, parts and% are parts by mass or mass% unless otherwise specified.
As a 2: 1 type iron complex salt compound, in the formula of the general formula (1), A = 5-Cl group, B = hydrogen atom, X = CH ₃ group, Y = unsubstituted phenyl group, J = hydrogen ion (general formula In the formula of (3), those in which X = CH ₃ group, C and D are hydrogen atoms, J = hydrogen ion) were selected. Among these, as impurities, in the formula of the general formula (2), A = 5-Cl group, B = hydrogen atom, X = CH ₃ group, Y = unsubstituted phenyl group (in the formula of the general formula (4), X = CH ₃ group, C and D are hydrogen atoms) were prepared so that the content was 0.9% by mass, and three types of 2: 1 type iron complex salt compounds were prepared. 5 parts of carbon black and styrene acrylic synthetic resin (Mitsui Chemicals, trade name CPR-200) are blended in the proportions shown in [Table 1] below, mixed thoroughly, heated, melted and kneaded, cooled, and pulverized and classified by conventional methods. As a result, a negatively chargeable toner having a volume average particle size of 9 ± 0.5 μm was obtained. This toner was mixed and shaken at a ratio of 4 to 100 parts by mass with a silicon-coated carrier (trade name: F96-100, manufactured by Powder Tech Co.) to charge the toner negatively, and then measured with a blow-off charge amount measuring device. . In this case, the content β of the monoazo compound of the general formula (2) in the 2: 1 type iron complex salt compound of the general formula (1) is 0.9% by mass, and Since the addition amount α of the 2: 1 type iron complex salt compound is 1% by mass, α × β = 0.9.

The toner was prepared in the same manner as in Example 1 except that the addition amount α of the 2: 1 type iron complex salt compound of the general formula (1) into the toner was 2% by mass, and measured with a blow-off charge amount measuring device. . In this case, α × β = 1.8.

The toner was prepared in the same manner as in Example 1 except that the addition amount α of the 2: 1 type iron complex salt compound of the general formula (1) into the toner was 3% by mass, and measured with a blow-off charge amount measuring device. . In this case, α × β = 2.7.

The 2: 1 type iron complex salt of the general formula (1) in the 2: 1 type iron complex salt compound of the general formula (1) is 3.1% by mass, and the 2: 1 type iron complex salt of the general formula (1) in the toner is used. The toner was prepared in the same manner as in Example 1 except that the compound addition amount α was 1% by mass, and the toner was measured with a blow-off charge measuring device. In this case, α × β = 3.1.

The toner was prepared in the same manner as in Example 4 except that the addition amount α of the 2: 1 type iron complex salt compound of the general formula (1) into the toner was 2 mass%, and measured with a blow-off charge measuring device. . In this case, α × β = 6.2.

The toner was prepared in the same manner as in Example 4 except that the addition amount α of the 2: 1 type iron complex salt compound of the general formula (1) into the toner was 3% by mass, and measured with a blow-off charge measuring device. . In this case, α × β = 9.3.

The 2: 1 type iron complex salt of the general formula (1) in the general formula (1) is set to 5.3 mass% in the 2: 1 type iron complex salt compound of the general formula (1). The toner was prepared in the same manner as in Example 1 except that the compound addition amount α was 1% by mass, and the toner was measured with a blow-off charge measuring device. In this case, α × β = 5.3.

[Comparative Example 1]
The 2: 1 type iron complex salt of the general formula (1) in the general formula (1) is set to 5.3 mass% in the 2: 1 type iron complex salt compound of the general formula (1). The toner was prepared in the same manner as in Example 1 except that the compound addition amount α was 2 mass%, and was measured with a blow-off charge amount measuring device. In this case, α × β = 10.6.

[Comparative Example 2]
The 2: 1 type iron complex salt of the general formula (1) in the general formula (1) is set to 5.3 mass% in the 2: 1 type iron complex salt compound of the general formula (1). The toner was prepared in the same manner as in Example 1 except that the compound addition amount α was 3% by mass, and the toner was measured with a blow-off charge amount measuring device. In this case, α × β = 15.9.

In addition, a time constant (τ), which is an index of charge rising property, was also calculated. The time constant (τ) is measured by a blow-off charge amount measuring device at regular intervals until reaching the saturation charge, and is described in Journal of Electrophotographic Society, P307, Vol. 27, No. 3 (1988). Then, ln (q _max −q) was calculated by the following equation, and the relationship between time t and ln (q _max −q) was plotted on a graph to obtain the time constant (τ).
(Q _max −q) / (q _max −q ₀ ) = exp (−t / τ)
Here, q _max is the saturation charge amount, q ₀ is the initial charge amount (here, the value when the charge time is 30 seconds), t is each measurement time, and the charge amount at that time is q.
Those with good rise in charge have a smaller time constant. The unit of time constant is seconds.

In addition, the environmental stability evaluation method for evaluating the environmental stability of the charge is not only a measurement in a normal 25 ° C.-50% RH (relative humidity) environment, but also in a high temperature and high humidity environment (35 The determination was made by measuring the charge amount at (° C.-85% RH).
In the measurement of the charge amount, the developer exposed for 24 hours in each environment was sufficiently charged while remaining in that environment, and the saturation charge amount was measured by a blow-off charge amount measuring device.
In two environments, a change in charge amount of less than 20% was evaluated as good (◯), and a value exceeding 20% was determined as poor (x). The results are shown in [Table 1].

From the results of [Table 1], the content of the monoazo compound of the general formula (2) β mass% in the 2: 1 type iron complex salt compound of the general formula (1) and 2 of the general formula (1) into the toner. It can be seen that the toner satisfying the condition that the product of the addition amount of α-type iron complex salt compound: α mass% satisfies the condition of 10 or less has a high charge amount and good charge rise and environmental stability.

The negatively chargeable electrophotographic toner of the present invention is required to have a high charge amount, rapid charge rise, and environmental stability since the specific impurity content is suppressed by the impurity suppression management method at the time of toner production. Suitable for use. It does not have a nitro group in the structural formula, and when it is required that there is no powder explosion at the time of toner production or because it does not contain metals such as chromium, it generates harmful substances even if it is burned or oxidized. Suitable when there is no requirement. It is also suitable as an impurity suppression management method during toner production.

Claims (8)

The following general formula (1)

(Expressed in the formula, A, B are each independently a hydrogen source frame other is a halogen atom, X represents an alkyl group having a carbon number of 1 to 8, Y is substituted with an unsubstituted aromatic ring group or a halogen atom the .J representing the aromatic ring group, a hydrogen ion, represents an alkali metal ion, ammonium ion, or alkylammonium ions, these ions in J may be mixed two or more kinds. However, X is A toner containing α% by mass of a 2: 1 type iron complex compound represented by the formula (1) as a charge control agent , except for a methyl group and Y being an unsubstituted phenyl group. The following general formula (2) containing β mass% as impurities

(Represents wherein, A, B are each independently a hydrogen source frame other is a halogen atom, X represents an alkyl group having a carbon number 1 to 8, Y is substituted with an unsubstituted aromatic ring group or a halogen atom In which the monoazo compound represented by the formula (1) is 1000 ppm or less in terms of the toner content, except for the case where X is a methyl group and Y is an unsubstituted phenyl group. In addition, a negatively chargeable electrophotographic toner produced by controlling the content α of the charge control agent in the toner to 1 to 3 mass% and setting α × β ≦ 10. The following general formula (3)

(Wherein, X represents an alkyl group having a carbon number of 1 to 8, C, D is hydrogen original frame other independently represents a halogen atom, J is hydrogen ion, alkali metal ions, ammonium ions or, Represents an alkylammonium ion, and two or more of these ions may be mixed in J, except that X is a methyl group and C and D are hydrogen atoms at the same time. A toner containing 2% by mass of a 2: 1 type iron complex salt compound as a charge control agent, wherein β mass% is contained as an impurity in the iron complex salt compound.

(Wherein, X represents an alkyl group having a carbon number of 1 to 8, C, D is hydrogen original frame other independently represents a halogen atom. However, X is a methyl group, the C and D At the same time, except for the case of a hydrogen atom, the content α of the charge control agent in the toner shall be 1 to 3% by mass in order to make the monoazo compound represented by , negatively chargeable electrophotographic toner characterized in that it is manufactured by setting management in α × β ≦ 10. The negatively chargeable electrophotographic toner according to claim 2, wherein X is a methyl group, C is a hydrogen atom, and D is a 4-chloro group in the general formula (3) and the general formula (4). . The negatively chargeable electrophotographic image according to claim 2, wherein X is a methyl group, C is a 3-chloro group, and D is a 4-chloro group in the general formula (3) and the general formula (4). Toner. The following general formula (1)

(Expressed in the formula, A, B are each independently a hydrogen source frame other is a halogen atom, X represents an alkyl group having a carbon number of 1 to 8, Y is substituted with an unsubstituted aromatic ring group or a halogen atom the .J representing the aromatic ring group, a hydrogen ion, represents an alkali metal ion, ammonium ion, or alkylammonium ions, these ions in J may be mixed two or more kinds. However, X is A toner containing α% by mass of a 2: 1 type iron complex compound represented by the formula (1) as a charge control agent , except for a methyl group and Y being an unsubstituted phenyl group. The following general formula (2) containing β mass% as impurities

(Expressed in the formula, A, B are each independently a hydrogen source frame other is a halogen atom, X represents an alkyl group having a carbon number of 1 to 8, Y is substituted with an unsubstituted aromatic ring group or a halogen atom In which the monoazo compound represented by the formula (1) is 1000 ppm or less in terms of the toner content, except for the case where X is a methyl group and Y is an unsubstituted phenyl group. In addition, the content α of the charge control agent in the toner is 1 to 3% by mass, and is controlled to be set to α × β ≦ 10. Impurities during production of negatively chargeable electrophotographic toner Control management method. The following general formula (3)

(Wherein, X represents an alkyl group having a carbon number of 1 to 8, C, D is hydrogen original frame other independently represents a halogen atom, J is hydrogen ion, alkali metal ions, ammonium ions or, Represents an alkylammonium ion, and two or more of these ions may be mixed in J, except that X is a methyl group and C and D are hydrogen atoms at the same time. A toner containing 2% by mass of a 2: 1 type iron complex salt compound as a charge control agent, wherein β mass% is contained as an impurity in the iron complex salt compound.

(Wherein, X represents an alkyl group having a carbon number of 1 to 8, C, D is hydrogen original frame other independently represents a halogen atom. However, X is a methyl group, the C and D At the same time, except for the case of a hydrogen atom, the content α of the charge control agent in the toner shall be 1 to 3% by mass in order to make the monoazo compound represented by , α × β ≦ 10 and sets managed, impurity suppression management method producing the toner for negative charging electrophotography. The negatively chargeable electrophotographic toner according to claim 6, wherein X is a methyl group, C is a hydrogen atom, and D is a 4-chloro group in the general formula (3) and the general formula (4). Impurity suppression management method during manufacturing. The negatively charged electrophotographic image according to claim 6, wherein X is a methyl group, C is a 3-chloro group, and D is a 4-chloro group in the general formula (3) and the general formula (4). Impurity suppression management method for manufacturing toner.