JP3152996B2 - Binder resin for positively chargeable toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner which is excellent in non-offset properties, fixing properties and anti-blocking properties used in electrophotography, electrostatic printing and the like, has excellent positive chargeability, and has no environmental pollution. To provide a binder resin for use.

[0002]

2. Description of the Related Art Toner and binder resin for toner used in copying machines and printers by electrophotography require the following properties: first, fixing property to paper, non-offset property to rollers, Secondly, there are charging characteristics which affect image formation.

With respect to the fixing property, it is most important to lower the fixing temperature due to an increase in printing speed, and a binder resin having good melt fluidity has been used as a binder resin for toner. Regarding the non-offset property, it is important that the toner is not offset to the roller even in a relatively high temperature range, and a high binder resin has been used as the toner binder resin. Regarding the blocking resistance, it is important that the toner does not block even if the temperature during storage of the toner is high, and a binder resin having a relatively high glass transition temperature (Tg) has been used as a binder resin for the toner.

[0004] Further, the charging characteristics which have the most influence on the image formation are important, and the problem of the charging amount and the charging stability (moisture resistance) are important.
Are roughly divided into Regarding the problem of the charge amount, the charge amount of the toner and the binder resin for the toner must be determined by a photoreceptor such as a copying machine or a printer, and the charge amount of the toner binder resin is determined by the monomer and molecular structure used. I've been in control. Regarding the charge stability, it is necessary that the charge amount does not change over time during printing and that the charge amount of the toner does not decrease at high humidity. This is prevented by the resin manufacturing method as a binder resin for toner. I've been.

[0005] There are two types of charging of the toner and the binder resin for the toner: a negative charging type and a positive charging type. The charging amount of the negative charging toner is adjusted by the negative charging resin and the negative charging control agent. Have been. Also, the positively chargeable toner uses a positively chargeable resin and a charge control agent like the negatively chargeable toner, but the control of the charge amount of the positively chargeable toner has various problems, Various researches have been conducted on positively chargeable binder resins for toner.

[0006]

In order to obtain a positively chargeable binder resin, an amine-based or amide-based monomer is generally used. However, when an amine-based or amide-based monomer is used, Requires the use of an azo-based polymerization initiator in the synthesis of the binder resin, resulting in differences in the resin reaction conditions and characteristic values, However, there is a problem that the moisture resistance is deteriorated and the charging stability is deteriorated, and the thermal characteristics of the toner are different, so that the color development of the toner is inferior. Furthermore, azobisisobutyronitrile, which is generally used as an azo-based polymerization initiator, has a problem of environmental pollution because a toxic substance having a CN group is generated as a decomposition by-product.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a binder resin for toner which has excellent non-offset properties, fixing properties and blocking resistance, and has excellent positive charging properties without environmental pollution.

[0008]

Means for Solving the Problems In view of such circumstances, the present inventors have conducted intensive studies on the relationship between the molecular weight of the binder resin and the positive chargeability of the resin for toner. By controlling the molecular weight, a positive charging property having an excellent charging level can be stably obtained, and a binder resin for a toner of the present invention having no environmental pollution has been found. That is,
Positively chargeable toner binder resin of the present invention comprises 1 to 40 wt% of acrylic acid ester component and / or methacrylic acid ester component without chromatic and amino group an ether group in the total polymer component, the glass transition temperature Is 40 ~
68 ° C, softening temperature 80-140 ° C, acid value 20mgK
OH / g or less, weight average molecular weight of 3,000 to 80,0
The number average molecular weight is from 1,000 to 45,000.

[0009] ami possess an ether group used in the present invention
Examples of the acrylate component or methacrylate component having no group include 2-ethoxyethyl acrylate, 2-methoxyethyl acrylate, 2-butoxyethyl acrylate, 2-ethoxyethyl methacrylate, 2-methoxyethyl methacrylate, 2-butoxyethyl methacrylate, and the like. Among them, 2-ethoxyethyl methacrylate is particularly preferred. In the present invention, to the accession <br/> acrylic acid ester component or methacrylate ester component having no chromatic and amino groups these ether groups may be used alone, used in combinations of two or more May be. The amount of acrylic <br/> Le ester component or methacrylate ester component having no possess an ether group amino group is required to be 1 to 40% by weight of the total polymer component, preferably It is in the range of 5 to 30% by weight. This is because if the amount used is less than 1% by weight, it is difficult to obtain a satisfactory charge amount due to poor positive chargeability. Conversely, if the amount used exceeds 40% by weight, the glass transition temperature of the toner becomes low. This is because the blocking resistance is inferior.

In the binder resin of the present invention, the weight average molecular weight is from 3,000 to 80,000, and the number average molecular weight is from 1,000 to 45,000, and the weight is controlled in this molecular weight region. Thereby, excellent positive chargeability can be obtained. This is because if the weight average molecular weight is less than 3,000, the glass transition temperature tends to be low and the blocking resistance is poor, and if it exceeds 80,000, the positive chargeability is poor, and therefore, it is preferable. Has a weight average molecular weight of 5,000 to 7
It is in the range of 0000. In addition, the number average molecular weight is 1,0
If it is less than 00, the glass transition temperature tends to be low, and the blocking resistance is poor.
If it exceeds 00, the positive chargeability is inferior, and the number average molecular weight is preferably in the range of 2,000 to 40,000.

The glass transition temperature of the binder resin of the present invention must be in the range of 40 to 68 ° C., preferably 50 to 65 ° C. This is because if the glass transition temperature is less than 40 ° C., the blocking resistance of the toner is poor, and if it exceeds 68 ° C., the fixability of the toner is poor. Further, in the binder resin of the present invention, the softening temperature needs to be in the range of 80 to 140 ° C, and preferably in the range of 90 to 135 ° C. This is because when the softening temperature is lower than 80 ° C., the non-offset property of the toner is poor, and when it exceeds 140 ° C., the fixing property of the toner is poor. The binder resin of the present invention has an acid value of 20 mgKOH /
g, preferably 15 mgK or less.
OH / g or less. This is because the acid value is 20mgK
If it exceeds OH / g, the moisture resistance of the toner is inferior.

[0012] As components other than the acrylic acid ester component or methacrylate ester component having no chromatic and amino groups of the above ether group constituting the binder resin of the present invention, styrene component, an acrylic acid ester component, methacrylic acid ester Component or unsaturated dibasic acid component. The amount of the styrene component, acrylate component, methacrylate component, unsaturated dibasic acid component, etc. used is selected according to the glass transition temperature, softening temperature and acid value of the binder resin of the present invention. 60-99 in the total polymer components in the total amount of the components
%, Preferably in the range of 70 to 95% by weight. Further, in these components, a combination with a styrene component, an acrylate component and a methacrylate component, a combination with an acrylate component and a methacrylate component, a styrene component, an acrylate component and / or a methacrylic acid component. A combination with an ester component and an unsaturated dibasic acid component is particularly preferred.

Examples of the styrene component include styrene, O-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, and p-methylstyrene. Ethylstyrene, 2,4-dimethylstyrene,
pn-butylstyrene, p-tertbutylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, α-methylstyrene And the like. Among them, styrene, p-methylstyrene and α-methylstyrene are particularly preferred. By using such a styrene component, the moisture resistance of the toner can be improved.

Further, the acrylic acid ester component or methacrylate ester component, amino possess an ether group
It is a component other than the acrylate component or methacrylate component having no group . Examples of the acrylate component include acrylic acid, ethyl acrylate, methyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, and the like. N-butyl acrylate,
2-Ethylhexyl acrylate is particularly preferred. Also,
Examples of the methacrylate component include methacrylic acid, ethyl methacrylate, methyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, propyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, and methacrylic acid. Glycidyl, cyclohexyl methacrylate and the like, among which methacrylic acid, methyl methacrylate,
N-Butyl methacrylate is particularly preferred. Such acrylic acid ester component or methacrylate ester component can be a positively chargeable toner with good synergistic with acrylic acid ester component or methacrylate ester component having no amino groups possess an ether group The effect is easily obtained.

Further, as the unsaturated dibasic acid component, for example, maleic acid, butyl maleate, methyl maleate, dimethyl maleate, fumaric acid, butyl fumarate,
Examples thereof include dibutyl fumarate, diisobutyl fumarate, dimethyl fumarate, and diethyl fumarate. Of these, dibutyl fumarate is particularly preferred. By using such an unsaturated dibasic acid component, it is possible to improve the positive chargeability of the toner. In the present invention, the styrene component, acrylic acid ester component, methacrylic acid ester component, even other than the unsaturated dibasic acid component, as long as it is a component having a double bond capable of radical polymerization, the polymer component Can be used as Examples thereof include vinyl aliphatic carboxylic acid ester components such as vinyl acetate, vinyl propionate, vinyl caproate, and vinyl laurate, with vinyl acetate being particularly preferred. Further, a reaction with a butadiene-based monomer and an unsaturated polyester may be performed.

In the binder resin of the present invention, a chain transfer agent component may be used as a softening temperature and molecular weight modifier. Examples of the chain transfer agent component include α-methylstyrene dimer, n-decyl mercaptan, Examples thereof include thioglycolic acid ester and n-octyl mercaptan. Among them, α-methylstyrene dimer and thioglycolic acid ester are particularly preferable. The binder resin of the present invention can be used alone as a binder resin for a toner, but may be a commonly used binder resin of styrene / acrylic, styrene / butadiene, polyester or the like, or a mixture thereof. They can be used in combination. Examples of the method for producing the binder resin of the present invention include methods such as bulk polymerization, suspension polymerization, emulsion polymerization, and solution polymerization. Two or more of these polymerization methods may be combined. These production methods are preferably selected according to the required characteristics of the toner.

The polymerization initiator used in the production of the binder resin of the present invention is not particularly limited as long as it is one used for ordinary radical polymerization. Is particularly preferred. Examples of the peroxide-based polymerization initiator include benzoyl peroxide, t-butylperoxyisobutyrate, t-butylperoxy 2-ethylhexanoate, t-butylperoxybenzoate, and t-butylperoxy. Examples thereof include isopropyl carbonate and di-t-butyl diperoxyisophthalate. These may be used alone or in combination of two or more.
Among them, benzoyl peroxide and t-butylperoxybenzoate are particularly preferred. Further, 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis (2,4′-dimethylvaleronitrile), 1,1-bis (t-butylperoxy) 3,3,3 5-trimethylcyclohexane, 1,1-azobis (cyclohexane-1-
Carbonitrile), 2,2′-azobis (2,4,4-
Even when an azo-based polymerization initiator such as trimethylpentane) is used, the effect of positive charging can be obtained.

When the binder resin of the present invention is produced by emulsion polymerization or suspension polymerization, ordinary emulsifiers and dispersants can be used. As emulsifiers and dispersants, polyvinyl alcohol, sodium polyacrylate dispersants,
Polyether-based dispersants, ethylene oxide-based dispersants and the like can be mentioned. Further, as dispersion aids, commonly used sodium sulfate, sodium carbonate, aqueous hydrogen peroxide,
Boric acid or the like can be used.

[0019]

The present invention will be specifically described below with reference to examples. In the examples, the glass transition temperature (Tg) was determined by heating the sample to 100 ° C. and melt quenching.
The measurement was performed at a heating rate of 10 ° C./min with a differential calorimeter. The softening temperature was measured using a flow tester CFT-500 manufactured by Shimadzu Corporation having a nozzle of 1.0 mmφ × 10 mm under the conditions of a load of 30 kgf and a heating rate of 3 ° C./min. The temperature at that time was defined as the softening temperature. The acid value was determined by a suitable method using KOH in a toluene solvent.

The molecular weight was determined by gel permeation chromatography HCL-8020 (manufactured by Toso Corporation) in terms of polystyrene. The positive chargeability was determined by weighing 0.45 parts by weight of the toner and 10 parts by weight of the carrier for positive charging in a 50 cc polyethylene container, and leaving the mixture at a temperature of 20 ° C. and a humidity of 60% for about 24 hours. About 20
A mixture 0.2 which was stirred and mixed at a speed of 0 rpm for about 30 minutes.
The parts by weight were weighed, the charge amount was measured using a blow-off charge amount measurement device (TB-500, manufactured by Toshiba Chemical Co., Ltd.), and the sign was inverted to calculate the charge amount per gram of toner. As a result, evaluation was made according to the following criteria.

：: Charge amount of 25 μC / g or more ○: Charge amount of 20 to 24 μC / g Δ: Charge amount of 14 to 20 μC / g ×: Charge amount of less than 14 μC / g The moisture resistance is the same as that of the positive charge. The amount of charge after being left for about 24 hours in an environment of a temperature of 35 ° C. and a humidity of 85% was determined, and the difference from the amount of charge after being left for about 24 hours in an environment of a temperature of 20 ° C. and a humidity of 60% was as follows. Was evaluated according to the criteria of

◎: less than 2 μC / g ：: less than 2 to 3 μC / g △: less than 3 to 4 μC / g ×: 4 μC / g or more For fixing properties, the printing speed was maintained at 20 mm / sec, and silicone oil was applied to the roller surface. The fixing temperature was measured using a fixing tester capable of freely changing the applied temperature, and the results were evaluated according to the following criteria.

◎: less than 120 ° C. ○: 120 to 139 ° C. Δ: 140 to 149 ° C .: 150 ° C. or more For non-offset property, use a fixing tester capable of freely changing temperature and speed. The generation temperature was measured, and the result was evaluated according to the following criteria.

◎: 170 ° C. or higher ：: 155 to 169 ° C. Δ: 140 to 154 ° C. ×: less than 140 ° C. The anti-blocking property is as follows. About 10 g of the toner is placed in a 200 cc crow container and kept at about 40 ° C. After leaving the glass container for about 120 hours, the state of aggregation of the toner when the removed glass container was inverted was evaluated according to the following criteria.

◎: The toner is uniformly dispersed. ト ナ ー: The toner is uniformly dispersed when hit twice. Δ: The toner is uniformly dispersed when hit four times. X: The toner is not aggregated and dispersed. In the evaluation of moisture resistance, fixing property, non-offset property and blocking resistance, those having ◎ to △ are practically usable.

Preparation of Dispersant A A reaction vessel equipped with a stirrer, thermometer and gas inlet tube was charged with 900 parts by weight of deionized water, 25 parts by weight of methyl methacrylate,
75 parts by weight of 3-sodium sulfopropyl methacrylate were charged, and N ₂ gas was blown in for about 30 minutes to expel air in the reaction system. Then, the mixture was heated from the outside with a hot water bath while stirring, the temperature was raised to 60 ° C., and 0.5 part by weight of ammonium persulfate was added. Stirring was continued at the same temperature for about 3 hours to obtain a polymer liquid (solid content 3.3%) having a viscosity of 340 centipoise (25 ° C.) having a bluish white appearance.

Examples 1-4 Mixed 220 parts by weight of deionized water, 0.60 part by weight of sodium polyacrylate (3.3% solids), 2.42 parts by weight of dispersant A, and 0.55 parts by weight of sodium sulfate And a stirrer,
It is charged into a reaction vessel equipped with a distillation tower and a thermometer, and then the monomers and additives in the amounts shown in Table 1 are mixed and charged. The stirring rotation speed is maintained at 300 rpm, and the polymerization is started in the amounts shown in Table 1. The agent was added. Then, the reaction vessel is externally heated with a hot water bath, and the temperature in the reaction system is increased to 92 over about 30 minutes.
The temperature was raised to ° C. to start suspension polymerization. After the suspension polymerization is carried out for about 6 hours, the temperature in the reaction system is raised to about 100 ° C., and about 44 parts by weight of the remaining monomer and deionized water in the reaction system are flowed out of the reaction system. The residual monomer of the polymer was reduced. Thereafter, the temperature in the reaction system was set to about 90 ° C., 0.5 parts by weight of sodium hydroxide was added, and alkali treatment was performed for about 30 minutes while maintaining the temperature at 90 ° C., and then the temperature in the reaction system was reduced to room temperature. The resin was taken out of the reaction vessel and washed with deionized water for about 5 minutes. Then, the resin was dried for about 48 hours with a hot air dryer at 50 ° C. to obtain a resin. Table 2 shows the characteristic values of the obtained resin.

Next, 90 parts by weight of the obtained resin, 5 parts by weight of carbon black and 5 parts by weight of a low-molecular-weight polypropylene wax are mixed for about 20 minutes, and mixed with a mixer for about 20 parts.
Melted and kneaded for minutes. Melt kneading was performed at a temperature 10 ° C. higher than the softening temperature of the resin. Next, the kneaded product was indirectly cooled by water cooling and coarsely pulverized, then finely pulverized by a jet mill pulverizer, adjusted in particle size by a classifier, and finally a toner having an area average particle size of 10 to 11 μm was obtained. Table 2 shows the evaluation results of the obtained toner for positive charge, moisture resistance, fixing property, non-offset property and blocking resistance. The results were evaluated and the results are shown in Table 2.

As shown in Table 2, the toner of Example 1 was
It showed positive chargeability and had a good charge level. Further, the toners of Examples 2 and 4 exhibited positive chargeability and had an excellent charge level. The toner of Example 3 exhibited positive chargeability and the charge amount was slightly low, but at a practical level. Further, the toners of Examples 1 to 4 exhibited excellent moisture resistance with little attenuation of the charge amount. Regarding fixability, Examples 1 to
The toner of No. 3 was good, and the toner of Example 4 showed excellent fixability. As for the non-offset property, the toners of Examples 1 to 3 were excellent, and the toner of Example 4 was good. Regarding the blocking resistance, Examples 1 and 3
The toner of Example 2 showed good blocking resistance, and the toner of Example 2 showed excellent blocking resistance. The toner of Example 4 was slightly inferior in blocking resistance, but at a practical level.

Examples 5 to 6 Under the same conditions as in Examples 1 to 4 except that the monomers, additives and polymerization initiators shown in Table 1 were used, except that deionized water and the remaining monomers were allowed to flow out at 100 ° C. A resin was obtained. Table 2 shows the characteristic values of the obtained resin. Further, the obtained resin was converted into a toner under the same conditions as in Examples 1 to 4. Positive charging property, moisture resistance, fixing property of the obtained toner,
Table 2 shows the evaluation results of the non-offset properties and the blocking resistance.

As shown in Table 2, regarding the positive chargeability,
The toners of Examples 5 and 6 exhibited positive chargeability and also had excellent charge levels. Further, the toners of Examples 5 and 6 were both excellent in moisture resistance and fixability. With respect to the non-offset property and the blocking resistance, the toner of Example 5 exhibited good non-offset property and blocking resistance, and the toner of Example 6 was slightly inferior in both the non-offset property and blocking resistance, but was practicable. Level.

Examples 7 to 8 Except for using the monomers, additives, and polymerization initiators shown in Table 1, except that the suspension polymerization temperature was set at 88 ° C. and the deionized water and the remaining monomers were allowed to flow out at 100 ° C. Examples 1-4
A resin was obtained under the same conditions as described above. Table 2 shows the characteristic values of the obtained resin. Further, the obtained resin was converted into a toner under the same conditions as in Examples 1 to 4. Table 2 shows the evaluation results of the obtained toner for positive charge, moisture resistance, fixing property, non-offset property and blocking resistance.

As shown in Table 2, regarding the positive charging property,
The toners of Examples 7 and 8 exhibited positive chargeability.
The toner of Example 8 showed a good charge level, and the toner of Example 8 had a slightly low charge level, but was at a practical level. Further, the toners of Examples 7 and 8 were all excellent in moisture resistance. Regarding the fixability, the toners of Examples 7 and 8 were slightly inferior, but at a practical level.
Regarding the non-offset properties and the anti-blocking properties, the toners of Examples 7 and 8 both showed excellent non-offset properties and anti-blocking properties.

Example 9 A resin was obtained under the same conditions as in Examples 1 to 4 except that the suspension polymerization temperature was 140 ° C. and the monomers, additives and polymerization initiator shown in Table 1 were used. Table 2 shows the characteristic values of the obtained resin. Further, the obtained resin was converted into a toner under the same conditions as in Examples 1 to 4. Positive chargeability of the obtained toner,
Table 2 shows the evaluation results of the moisture resistance, the fixing property, the non-offset property, and the blocking resistance. As shown in Table 2, it exhibited positive chargeability, was excellent in charge level, and was excellent in moisture resistance.
In addition, it exhibited excellent fixing properties and good non-offset properties. Although the blocking resistance was slightly inferior, it was at a practical level.

Examples 10 to 15 Resins were obtained in the same manner as in Examples 1 to 4, except that the monomers, additives and polymerization initiators shown in Table 1 were used. Table 2 shows the characteristic values of the obtained resin. Further, the obtained resin was converted into a toner under the same conditions as in Examples 1 to 4. Table 2 shows the evaluation results of the obtained toner for positive charge, moisture resistance, fixing property, non-offset property and blocking resistance.

As shown in Table 2, regarding the positive charging property,
The toners of Examples 10 to 15 exhibited positive chargeability, and all were excellent in charge level. Further, the toners of Examples 10 to 14 exhibited excellent moisture resistance, and the toner of Example 15 was slightly inferior in moisture resistance, but at a practical level. Regarding the fixing property and the non-offset property, Examples 10 to 15 were used.
All of the toners had good fixing properties and exhibited excellent non-offset properties. With respect to blocking resistance, the toners of Examples 10, 11 and 13 were good, and the toners of Examples 12, 14 and 15 showed excellent blocking resistance.

[0037]

[Table 1]

[0038]

[Table 2]

Comparative Example 1 A resin was obtained in the same manner as in Examples 1 to 4, except that the monomers, additives and polymerization initiator shown in Table 3 were used.
Table 4 shows the characteristic values of the obtained resin. Further, the obtained resin was converted into a toner under the same conditions as in Examples 1 to 4.
Table 4 shows the evaluation results of the obtained toner for positive charging property, moisture resistance, fixing property, non-offset property and blocking resistance. As shown in Table 4, the chargeability was poor and the charge level was not satisfactory.

Comparative Example 2 A resin was obtained in the same manner as in Example 7, except that the monomers, additives and polymerization initiator shown in Table 3 were used. Table 4 shows the characteristic values of the obtained resin. Further, the obtained resin was converted into a toner under the same conditions as in Examples 1 to 4. Table 4 shows the evaluation results of the obtained toner for positive charging property, moisture resistance, fixing property, non-offset property and blocking resistance.
As shown in Table 4, the fixing property and the blocking resistance were inferior and were unpractical.

Comparative Example 3 A resin was obtained in the same manner as in Examples 1 to 4, except that the monomers, additives and polymerization initiator shown in Table 3 were used.
Table 4 shows the characteristic values of the obtained resin. Further, the obtained resin was converted into a toner under the same conditions as in Examples 1 to 4.
Table 4 shows the evaluation results of the obtained toner for positive charging property, moisture resistance, fixing property, non-offset property and blocking resistance. As shown in Table 4, the fixing property was inferior and was impractical.

Comparative Example 4 A resin was obtained in the same manner as in Example 9 except that the polymerization temperature was 145 ° C., and monomers, additives and a polymerization initiator having the compositions shown in Table 3 were used. Table 4 shows the characteristic values of the obtained resin. Furthermore, the obtained resin was used in Examples 1 to
The toner was formed under the same conditions as in Example 4. Table 4 shows the evaluation results of the obtained toner for positive charging property, moisture resistance, fixing property, non-offset property and blocking resistance. As shown in Table 4,
It was inferior in moisture resistance, non-offset property and blocking resistance, and was not practical.

Comparative Example 5 A resin was obtained in the same manner as in Examples 1 to 4, except that a monomer, an additive and a polymerization initiator having the compositions shown in Table 3 were used. Table 4 shows the characteristic values of the obtained resin. Further, the obtained resin was converted into a toner under the same conditions as in Examples 1 to 4. Positive charging property, moisture resistance, fixing property of the obtained toner,
Table 4 shows the evaluation results of the non-offset properties and the blocking resistance. As shown in Table 4, it was inferior in moisture resistance and was not practical.

[0044]

[Table 3]

[0045]

[Table 4]

The symbols in Tables 1 and 3 indicate the following components, respectively. St: styrene nBA: n-butyl acrylate MAA: methacrylic acid MMA: methyl methacrylate ET: 2-ethoxyethyl methacrylate AET: 2-ethoxyethyl acrylate MT: 2-methoxyethyl methacrylate DBF: dibutyl fumarate VAC: Vinyl acetate DE: diethylaminoethyl methacrylate MSD: α-methylstyrene dimer BPO: benzoyl peroxide tBP: t-butylperoxybenzoate AIBN: azobisisobutyronitrile

[0047]

The toner using the binder resin of the present invention is excellent in fixing property, non-offset property and blocking resistance, has excellent positive chargeability, and has a stable charge amount. Furthermore, the binder resin of the present invention does not use azobisisobutyronitrile, which has a problem of toxicity,
Also, by using a peroxide-based polymerization initiator, a good positively chargeable toner can be obtained, and there is no environmental pollution.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 9/08

Claims (3)

(57) [Claims] 1. A comprising 1 to 40% by weight of A <br/> acrylic acid ester component and / or methacrylic acid ester component without chromatic and amino group an ether group in the total polymer component, the glass transition temperature of 40 ~ 68 ° C, softening temperature 80 ~ 140
° C, an acid value of 20 mgKOH / g or less, a weight average molecular weight of 3,000 to 80,000, and a number average molecular weight of 1,000.
A binder resin for a positively chargeable toner, wherein the binder resin has a molecular weight of 45,000. 2. It contains at least one or more components selected from a styrene component, an acrylate component, a methacrylate component, and an unsaturated dibasic acid component, and the total amount of these components is 60 to 60 in the total polymer component. The binder resin for a positively chargeable toner according to claim 1, wherein the content is 99% by weight. 3. The method of claim 1, wherein at least one peroxide polymerization initiator is used.
3. The binder resin for a positively chargeable toner according to claim 1, wherein at least one kind is used.