JPH09292736A - Toner for developing electrostatic images - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a toner having a sufficiently wide anti-offsetting temp. region, fixable at a low temp., excellent in fixing strength and giving sufficiently high image density even after copying repeated many times by incorporating vinyl polymer grafted polyester resin and vinyl copolymer resin. SOLUTION: This toner contains vinyl polymer grafted polyester resin and vinyl copolymer resin. Since the vinyl polymer grafted polyester resin is used as polyester resin, compatibility with the vinyl copolymer resin is improved and uniform mixing is enabled. The pref. vinyl polymer content of the grafted polyester resin is 1-50wt.%, especially 4-30wt.%. The grafted polyester resin is produced by allowing diol to react with dicarboxylic acid, its lower alkyl ester or anhydride and a vinyl macromonomer having a dihydroxyl group or a dicarboxyl group at one terminal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic charge image developing toner used in electrophotography, electrostatic recording, electrostatic printing and the like.

[0002]

2. Description of the Related Art In an electrophotographic method, an electrostatic recording method, an electrostatic printing method, or the like, an electrostatic charge image formed on a photoreceptor is visualized using toner particles in which a colorant or the like is dispersed in a resin. This visualized image is fixed on the photoreceptor as it is,
Alternatively, it is fixed after being transferred to a transfer paper. That is, the characteristics required for the toner include not only the developability but also the good transferability and fixability. Especially,
In recent years, low energy fixing has been strongly demanded from the viewpoint of energy saving. As a heat fixing method,
There are a non-contact heating method such as oven fixing and a contact heating fixing method of heat roller fixing. The contact heating fixing method has high thermal efficiency, does not require a large amount of power for the fixing section, and can be downsized, and is a method that is in line with the times from the viewpoint of energy saving. However, this method has a problem that an offset occurs. Offset means that at the time of fixing, part of the toner forming the image is transferred to the surface of the heating roller, and this is transferred onto the transfer paper that is sent next.
This is a phenomenon that contaminates the image. In order to prevent this offset phenomenon, various proposals have been made and put to practical use. One of the methods is to include a compound having releasability such as wax in a toner, and this method is widely practiced. However, when this compound is blended, the wax adheres to the photoreceptor, so-called filming is likely to occur, and the storage stability of the toner is poor. In addition, offset can be prevented by using a high molecular weight polymer as a resin constituting the toner, but the softening point is increased and the fixing temperature is increased, and the resin is tough and pulverization during toner production becomes difficult. Not practical. In order to improve these disadvantages, it has been proposed to use a polymer having a wide molecular weight distribution from a low molecular weight to a high molecular weight in a toner using a vinyl resin such as styrene. This toner is somewhat satisfactory in terms of offset prevention and fixability, but
The fixability at low temperatures is not satisfactory. On the other hand, a condensation resin such as a polyester resin gives a polymer having a relatively low molecular weight, and therefore it has been proposed that a toner capable of fixing at a low temperature can be produced by using this, but it has a hot offset resistance. It was insufficient. Therefore, in order to solve these problems, a toner using a mixture of a high molecular weight vinyl resin and a low molecular weight polyester resin, which takes in such characteristics of the vinyl resin and the condensation resin, is also disclosed in JP-A-54-54. 114245, JP-A-58-1
No. 1955 and Japanese Patent Laid-Open No. 58-14147. Although these toners have some effect on the hot offset resistance, a new problem arises in that the toner cannot be uniformly mixed, and the toner tends to have non-uniform triboelectrification. Further, as one monomer component of the polyester resin, a trivalent or higher alcohol and / or 3
To prevent offset by using a resin having a crosslinked structure using a carboxylic acid having a valency or more as a resin for toner, it is disclosed in JP-A-54-86342 and JP-A-56-1952.
JP-A-56-21136, JP-A-56-1686
60, JP-A-57-37353, JP-A-58-14
146, JP-A-59-30542, JP-A-61-1.
05561, JP-A 61-105563, JP-A 6-
It is disclosed in JP-A No. 1-124961 and JP-A No. 61-275769.

[0003]

However, even in toners using these resins, if the amount of the polyhydric alcohol or carboxylic acid added is 30 mol% or less, the crosslinking reaction is not sufficiently carried out and the effect of preventing offset is insufficient. However, if added more than that, there is an offset preventing effect, but there is a problem that unreacted alcoholic hydroxyl group or carbonyl group of carboxylic acid is likely to remain, and the moisture resistance of the toner is significantly lowered. Further, since the crosslinking reaction proceeds too much, the melting start temperature of the resin rises and the fixing temperature of the toner also rises accordingly, which is not useful for low temperature fixing. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a novel toner for developing an electrostatic image in which the problems of the known toners described above are improved. Still another object of the present invention is to provide an energy-saving type electrostatic image developing toner suitable for a heat fixing method.

[0004]

SUMMARY OF THE INVENTION The present invention is a toner for developing an electrostatic charge image, which comprises a vinyl polymer graft polyester resin and a vinyl copolymer resin. Polyester resin and vinyl resin cannot be mixed uniformly, but by using vinyl polymer graft polyester resin as polyester resin,
The compatibility with the vinyl resin is improved and uniform mixing is possible. The vinyl polymer graft polyester resin is produced by the reaction of a diol component, a dicarboxylic acid component or a lower alkyl ester thereof or an acid anhydride thereof, and a vinyl macromonomer having a dihydroxyl group or a dicarboxyl group at one end. it can.

The main constituent components of the vinyl polymer graft polyester resin used in the present invention are described below. As the diol component, diethanolamine, ethylene glycol, diethylene glycol, propylene glycol, isopropylene glycol, octane diol,
2,2-diethyl-1,3-propanediol, spiroglycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 2-butyl-2
-Ethyl-1,3-propanediol, 1,6-hexanediol, hexylene glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, hydrobenzoin, bis (β-hydroxyethyl) terephthalate , Bis (hydroxybutyl) terephthalate,
Examples thereof include polyoxyethylenated bisphenol A, polyoxypropyleneized bisphenol A, polyoxyethylenated biphenol, and polyoxypropyleneized biphenol. Further, as the dicarboxylic acid, fumaric acid, maleic acid, succinic acid, itaconic acid, mesaconic acid, citraconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid,
Cyclohexene dicarboxylic acid, adipic acid, sebacic acid, dodecanedioic acid, naphthalenedicarboxylic acid, biphenyl-4,4'-dicarboxylic acid, 2,3-piperazine dicarboxylic acid, iminodicarboxylic acid, imidazole-4,
5-dicarboxylic acid, piperidine dicarboxylic acid, pyrazole dicarboxylic acid, N-methylpyrazole dicarboxylic acid, N-phenylpyrazole dicarboxylic acid, pyridinedicarboxylic acid, carbazole-3,6-dicarboxylic acid, 9
-Methylcarbazole-3,6-dicarboxylic acid, carbazole-3,6-dibutyric acid, carbazole-3,6-γ,
Examples thereof include γ'-diketobutyric acid, its acid anhydride, its lower alcohol ester and the like.

As the vinyl-based macromonomer having a dihydroxyl group at one end, a dihydroxyl type polystyrene macromonomer (trade name: manufactured by Toagosei Kagaku Kogyo Co., Ltd .:
HS-6), dihydroxyl type polystyrene acrylonitrile macromonomer (trade name: HN-6 manufactured by Toagosei Chemical Industry Co., Ltd.), dihydroxyl type polymethylmethacrylate macromonomer (trade name: HA-6 manufactured by Toagosei Chemical Industry Co., Ltd.), etc. Is mentioned. Examples of the vinyl macromonomer containing a dicarboxyl group at one end include dicarboxyl type polystyrene macromonomer (trade name: CS-6 manufactured by Toagosei Chemical Industry Co., Ltd.), dicarboxyl type polystyrene acrylonitrile macromonomer (trade name of Toagosei Chemical Industry Co., Ltd.). : CN-6), dicarboxyl type polybutyl acrylate macromonomer (trade name: CB-6 manufactured by Toagosei Kagaku Kogyo Co., Ltd.) and the like.

The main constituent components of the vinyl copolymer resin used in the present invention will be described below. Examples of the styrene-based monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene,
pn-butyl styrene, p-dodecyl styrene, p-
Methoxystyrene, p-phenylstyrene, p-chlorostyrene and the like can be mentioned. As acrylic monomers,
Methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, stearyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate , Stearyl methacrylate, cyclohexyl methacrylate, dimethylaminoethyl methacrylate and the like. These monomers can be used alone or in combination of two or more.

The content of the vinyl polymer in the vinyl polymer graft polyester resin used in the present invention is preferably 1 to 50% by weight. More preferably, 4
３０30% by weight. When the content of the vinyl-based polymer is less than the lower limit of the range, it is difficult to uniformly mix it at the time of mixing because the compatibility with the vinyl-based copolymer resin is poor. The characteristics of the vinyl-based polymer such as poor fixing to transfer paper become stronger, and the low-temperature fixability of the polyester resin may be lost. In addition, the content of the vinyl-based polymer in the present invention means the weight (%) of the vinyl-based macromonomer in the total monomer components (weight) in the monomer components of the graft polyester resin. The molecular weight peak in the GPC chromatogram of the vinyl polymer graft polyester resin is preferably 10 ³ to 2 × 10 ⁴ . When the molecular weight peak is smaller than the lower limit of the range, the mechanical strength of the resin is small, and therefore, the resin is easily crushed by collision with the carrier and the durability as a developer is lost. On the other hand, when the amount is larger than the upper limit of the range, the resin strength increases and the pulverizability after melt-kneading deteriorates. The melting start temperature of the vinyl polymer graft polyester resin is 50 to 1
It is preferably 10 ° C. More preferably, 70
１００100 ° C. If the melting start temperature is lower than the lower limit of the range, blocking resistance is insufficient, and conversely, if the melting start temperature is higher than the upper limit of the range, sufficient low temperature fixability cannot be obtained. Further, the content of the vinyl copolymer resin in the resin component is preferably 1 to 50% by weight. More preferably, it is 5 to 30% by weight. If the content is less than the lower limit of the range, the offset resistance becomes insufficient, and conversely if it is more than the upper limit of the range, the melting start temperature and the flow softening point become high, and the lowering of the fixing lower limit temperature and the fixing strength A decrease occurs and sufficient low temperature fixability cannot be obtained. The molecular weight peak in the GPC chromatogram of the vinyl-based copolymer resin used in the present invention is 1
0 ⁵ to 10 ⁷ are preferable. When the molecular weight peak is smaller than the lower limit of the range, the melt viscosity of the resin is low and the offset resistance is insufficient. On the other hand, if it is larger than the upper limit of the range, the melt viscosity becomes too high, and it becomes difficult to mix the resin.

The vinyl polymer graft polyester resin of the present invention comprises a diol component, a dicarboxylic acid component or a lower alkyl ester thereof or an acid anhydride thereof, and a dihydroxyl or dicarboxyl group macromonomer at one end at a temperature of 180 to 260 ° C. It is obtained by a polycondensation reaction with. The reaction is preferably performed in an inert gas such as nitrogen gas. The reaction may be accelerated by reducing the pressure in the reaction system to a vacuum of 10 mmHg or less. At the time of the reaction, an esterification catalyst such as zinc oxide, dibutyltin oxide, tetrabutoxytitanate, and p-toluenesulfonic acid may be used. The vinyl polymer graft polyester resin used in the present invention is a differential scanning calorimeter (D
The glass transition temperature measured by SC) is preferably 50 ° C. or higher, more preferably 50-80 ° C., and the flow softening point measured by a Koka type flow tester is preferably 80-.
The temperature is 150 ° C, more preferably 80 to 130 ° C.

The melting start temperature and the flow softening point measured by a Koka type flow tester were measured by the following methods. The model used was Shimadzu's advanced flow tester CFT.
-500C. First, the resin pellets are placed in a cylinder having an area of about 1 cm ² preheated to about 50 to 80 ° C. A nozzle having a diameter of 1 mm and a length of 1 mm is provided at the bottom of the cylinder. A 1 cm ² area plunger with a load of 20 kgF is set on top of the resin pellets. The resin pellets in the cylinder are heated at a temperature rising rate of 6 ° C./min, and the softened resin is discharged from the nozzle. The temperature at the start of the descent of the plunger was taken as the melting start temperature, and the temperature at the time when the plunger reached half the distance to the bottom of the cylinder was taken as the flow softening point.

The toner for developing an electrostatic image of the present invention is produced by mixing a vinyl polymer graft polyester resin, a vinyl copolymer resin, a colorant and other additives, hot melt kneading, pulverizing and classifying. it can. Supermixer for mixing, uniaxial extrusion kneader for hot melt kneading, 2
Axial extrusion kneader, extruder, roller mixer,
A Banbury mixer, a pressure kneader, etc. are used, a jet mill is used for pulverization, and a dry airflow classifier is used for classification.

The colorants used in the present invention include garbon black, aniline blue, phthalocyanine blue,
Quinoline yellow, malachite green, lamp black, rhodamine-B, quinacridone and the like. The amount of the colorant added is 1 to 20% by weight based on the resin. As the charge control agent, for a positively charged toner, nigrosine dye, anthenium salt, pyridinium salt, azine or the like is added in an amount of 0.1 to 10% by weight based on the resin. A toner using a polyester resin generally gives a negative charge. When a charge control agent for a negative charge toner is added as necessary, a chromium complex, an iron complex, or the like is used. Further, when the negative chargeability is too strong, it is possible to control the neutralization by adding the positive charge control agent.

[0013]

The present invention will be described in detail below with reference to synthetic examples of resins used in the present invention and examples of the present invention, but the present invention is not limited to these examples. <Synthesis of vinyl-based polymer-grafted polyester resin> Synthesis example 1 Polyoxyethylenated bisphenol A 252.8 g,
68.8 g of polyoxypropyleneized bisphenol A,
166.1 g of terephthalic acid, 45 g of a dihydroxyl group-terminated polystyrene macromonomer (trade name: HS-6 manufactured by Toagosei Chemical Industry Co., Ltd.) and 0.05 of dibutyltin oxide.
g into a glass 1 liter 4-necked flask, equipped with a thermometer, a stirrer, a downflow condenser and a nitrogen introducing tube, and heated with a mantle heater to 180 to 220 ° C.
The reaction was carried out at a reaction temperature of 6 hours under a nitrogen stream to obtain a polystyrene graft polyester resin (G-1). Tg of the obtained resin by DSC was 63 ° C., melting start temperature by a flow tester was 85 ° C., and flow softening point was 105 ° C. The molecular weight peak measured by GPC is 5 ×.
It was 10 ³ , and the content of the vinyl polymer was 8.4%. Synthesis Example 2 126.4 g of polyoxyethylenated bisphenol A,
Polyoxypropylene bisphenol A 206.4
g, isophthalic acid 166.1 g, dihydroxyl group-terminated polystyrene acrylonitrile macromonomer (trade name: HN-6 manufactured by Toagosei Kagaku Kogyo Co., Ltd.) and dibutyltin oxide 0.05 g were placed in a four-necked flask, and Synthesis Example 1
A polystyrene acrylonitrile-grafted polyester resin (G-2) was obtained by synthesizing by the same operation as above. The obtained resin has a DSC Tg of 65 ° C., a flow tester melting start temperature of 88 ° C., and a flow softening point of 107 ° C.
Met. The molecular weight peak measured by GPC is
It was 4.8 × 10 ³ , and the content of the vinyl polymer was 4.8%. Synthesis Example 3 214.9 g of polyoxyethylenated bisphenol A,
58.5 g of polyoxypropylene bisphenol A,
166.1 g of terephthalic acid, 50 g of dihydroxyl group-terminated polymethylmethacrylate macromonomer (trade name: HA-6 manufactured by Toagosei Kagaku Kogyo Co., Ltd.) and 0.05 g of dibutyltin oxide were placed in a 4-neck flask, and the same procedure as in Synthesis Example 1 was performed. It synthesize | combined by operation and the polymethylmethacrylate graft polyester resin (G-3) was obtained. The Tg of the obtained resin was 63 ° C., the melting start temperature was 84 ° C., and the flow softening point was 105 ° C. The molecular weight peak measured by GPC was 4.2 × 10 ³ , and the content of the vinyl polymer was 10.2%. Synthesis Example 4 158 g of polyoxyethylenated bisphenol A, 172 g of polyoxypropyleneized bisphenol A, 132.9 g of isophthalic acid, dicarboxyl group terminated polystyrene macromonomer (trade name: C manufactured by Toagosei Kagaku Kogyo Co., Ltd.
S-6) 30 g and dibutyl tin oxide 0.05 g 4
The mixture was placed in a necked flask and synthesized in the same manner as in Synthesis Example 1 to give polystyrene-grafted polyester resin (G-4).
I got Tg of the obtained resin was 63 ° C., melting start temperature was 83 ° C., and flow softening point was 102 ° C. Also, GP
The molecular weight peak measured by C is 4.9 × 10 ³ ,
The content of the vinyl polymer was 6.1%. Synthesis Example 5 63.2 g of polyoxyethylenated bisphenol A, 275.2 g of polyoxypropyleneated bisphenol A,
132.9 g of terephthalic acid, 35 g of a polycarboxylate-terminated polybutyl acrylate macromonomer (trade name: CB-6 manufactured by Toagosei Kagaku Kogyo Co., Ltd.) and 0.05 g of dibutyltin oxide were placed in a 4-neck flask, and the same procedure as in Synthesis Example 1 was performed. It synthesize | combined by operation and the polybutyl acrylate graft polyester resin (G-5) was obtained. Tg of the obtained resin
Is 62 ° C, melting start temperature is 81 ° C, flow softening point is 99
° C. The molecular weight peak measured by GPC is
It was 5.8 × 10 ³ , and the content of the vinyl polymer was 5.9%.

<Synthesis of Ordinary Polyester Resin> Comparative Synthetic Example 1 Synthetic Example 1 except that HS-6 of Synthetic Example 1 was charged without using.
Polyester resin (P-1) was obtained by the same operation as. The obtained resin has a Tg of 62 ° C. and a melting start temperature of 86.
C., the flow softening point was 105.degree. The molecular weight peak measured by GPC was 5.1 × 10 ³ . Comparative Synthesis Example 2 Synthesis Example 2 except that HN-6 of Synthesis Example 2 was charged without use.
Polyester resin (P-2) was obtained by the same operation as. The obtained resin has a Tg of 64 ° C. and a melting start temperature of 86.
C., the flow softening point was 104.degree. The molecular weight peak measured by GPC was 4.9 × 10 ³ . Comparative Synthesis Example 3 Synthesis Example 3 except that HA-6 of Synthesis Example 3 was charged without use.
Polyester resin (P-3) was obtained by the same operation as. The obtained resin has a Tg of 64 ° C. and a melting start temperature of 86.
C., the flow softening point was 105.degree. The molecular weight peak measured by GPC was 4.1 × 10 ³ . Comparative Synthesis Example 4 Synthesis Example 4 except that CS-6 of Synthesis Example 4 was charged.
Polyester resin (P-4) was obtained by the same operation as. The obtained resin has a Tg of 62 ° C. and a melting start temperature of 83.
C., the flow softening point was 103.degree. The molecular weight peak measured by GPC was 4.5 × 10 ³ . Comparative Synthesis Example 5 Synthesis Example 5 except that CB-6 of Synthesis Example 5 was charged without use.
Polyester resin (P-5) was obtained by the same operation as. The obtained resin has a Tg of 65 ° C. and a melting start temperature of 86.
C., the flow softening point was 109.degree. The molecular weight peak by GPC measurement was 4.8 × 10 ³ .

<Production of Toner> Example 1 Graft polyester resin (G-1) 80 parts by weight Vinyl copolymer resin (A-1) 20 parts by weight Carbon black (MA-100 manufactured by Mitsubishi Chemical Corporation) 5 parts by weight Chromium complex salt dye (TRH manufactured by Hodogaya Chemical Co., Ltd.) 2 parts by weight Low molecular weight polypropylene (Viscole 330P manufactured by Sanyo Kasei Co., Ltd.) 2 parts by weight After mixing the mixture having the above composition with a super mixer, a twin-screw kneader Melt kneaded. After cooling the melt-kneaded product, pulverization and classification were performed to obtain negatively-chargeable toner particles having an average particle diameter of 10 μm. 0.5 parts by weight of hydrophobic colloidal silica was externally added to 100 parts by weight of the toner particles using a Henschel mixer to obtain a toner for developing an electrostatic image of the present invention. The Tg of the toner was 63 ° C., the melting start temperature was 96 ° C., and the flow softening point was 122 ° C. As the vinyl copolymer resin (A-1), a styrene butyl acrylate copolymer having a molecular weight peak of 8 × 10 ⁵ (monomer composition: styrene 70 / butyl acrylate 30) was used. Example 2 Graft polyester resin (G-2) 75 parts by weight Vinyl copolymer resin (A-2) 25 parts by weight Carbon black (MA-600 manufactured by Mitsubishi Chemical Corporation) 5 parts by weight Chromium-based complex salt dye 2 parts by weight ( Orient Chemical Co., Ltd. Bontron S-34) Low molecular weight polypropylene (Sanyo Kasei Co., Ltd. Viscole 330P) 2 parts by weight A mixture having the above composition was treated in the same manner as in Example 1 to obtain the electrostatic image developing toner of the present invention. Obtained. The toner had a Tg of 63 ° C., a melting start temperature of 98 ° C., and a flow softening point of 129 ° C. The vinyl-based copolymer resin (A-
As 2), a styrene-acrylonitrile copolymer having a molecular weight peak of 5.8 × 10 ⁵ (monomer composition: styrene 60 / acrylonitrile 40) was used. Example 3 90 parts by weight of graft polyester resin (G-3) Vinyl copolymer resin (A-3) 10 parts by weight Carbon black (MA-600 manufactured by Mitsubishi Chemical Corporation) 5 parts by weight Chromium complex salt dye 2 parts by weight ( Orient Chemical Co., Ltd. Bontron S-44) Low molecular weight polypropylene (Sanyo Kasei Co., Ltd. Viscole 330P) 2 parts by weight A mixture of the above-mentioned compounding mixture was subjected to the same procedure as in Example 1 to carry out the electrostatic image developing toner of the present invention. Got The toner had a Tg of 65 ° C., a melting start temperature of 92 ° C., and a flow softening point of 120 ° C. The vinyl-based copolymer resin (A-
As 3), a methyl methacrylate butyl acrylate copolymer (monomer composition: methyl methacrylate 80 / butyl acrylate 20) having a molecular weight peak of 3.5 × 10 ⁵ was used. Example 4 Graft polyester resin (G-4) 70 parts by weight Vinyl copolymer resin (A-1) 30 parts by weight Carbon black (MA-100 manufactured by Mitsubishi Chemical Corporation) 5 parts by weight Chromium-based complex salt dye (Hodogaya Chemical Co., Ltd. TRH) manufactured by Kogyo Co., Ltd. 2 parts by weight Low molecular weight polypropylene (Viscole 330P manufactured by Sanyo Kasei Kogyo Co., Ltd.) 2 parts by weight A mixture having the above composition was treated in the same manner as in Example 1 to obtain the toner for developing an electrostatic image of the present invention. Obtained. The toner had a Tg of 64 ° C., a melting start temperature of 97 ° C., and a flow softening point of 125 ° C. Example 5 Graft polyester resin (G-5) 70 parts by weight Vinyl copolymer resin (A-3) 30 parts by weight Carbon black (MA-100 manufactured by Mitsubishi Chemical Corporation) 5 parts by weight Chromium-based complex salt dye 2 parts by weight ( Orient Chemical Co., Ltd. Bontron S-44) Low molecular weight polypropylene (Sanyo Kasei Co., Ltd. Viscole 330P) 2 parts by weight A mixture of the above-mentioned compounding mixture was subjected to the same procedure as in Example 1 to carry out the electrostatic image developing toner of the present invention. Got The toner had a Tg of 64 ° C., a melting start temperature of 95 ° C., and a flow softening point of 125 ° C.

Comparative Example 1 Polyester resin (P-1) of Comparative Synthesis Example 60 60 parts by weight Vinyl copolymer resin (A-1) 40 parts by weight Carbon black (MA-100 manufactured by Mitsubishi Chemical Corporation) 5 parts by weight Chromium Complex salt dye (TRH manufactured by Hodogaya Chemical Co., Ltd.) 2 parts by weight Low molecular weight polypropylene (Viscole 330P manufactured by Sanyo Kasei Co., Ltd.) 2 parts by weight The mixture having the above composition was treated in the same manner as in Example 1 to obtain toner particles. Got Tg of the toner is 64 ° C.,
The melting start temperature was 92 ° C and the flow softening point was 108 ° C. Comparative Example 2 Polyester resin (P-2) of Comparative Synthesis Example 70 70 parts by weight Vinyl copolymer resin (A-2) 30 parts by weight Carbon black (MA-100 manufactured by Mitsubishi Chemical Corporation) 5 parts by weight Chromium complex salt dye 2 parts by weight (Bontron S-34 manufactured by Orient Chemical Co., Ltd.) Low molecular weight polypropylene (Viscor 330P manufactured by Sanyo Kasei Kogyo Co., Ltd.) 2 parts by weight The mixture having the above composition was subjected to the same operation as in Example 1 to obtain toner particles. It was Tg of the toner is 62 ° C.,
The melting start temperature was 91 ° C and the flow softening point was 107 ° C. Comparative Example 3 Polyester resin (P-3) of Comparative Synthesis Example 90 90 parts by weight Vinyl copolymer resin (A-3) 10 parts by weight Carbon black (MA-100 manufactured by Mitsubishi Chemical Corporation) 5 parts by weight Chromium-based complex salt dye (TRH manufactured by Hodogaya Chemical Co., Ltd.) 2 parts by weight Low molecular weight polypropylene (Viscole 330P manufactured by Sanyo Kasei Kogyo Co., Ltd.) 2 parts by weight The mixture having the above composition was treated in the same manner as in Example 1 to obtain toner particles. . Tg of the toner is 65 ° C.,
The melting start temperature was 90 ° C and the flow softening point was 106 ° C. Comparative Example 4 Polyester resin of Comparative Synthesis Example 4 (P-4) 92 parts by weight Vinyl copolymer resin (A-1) 8 parts by weight Carbon black (MA-100 manufactured by Mitsubishi Chemical Corporation) 5 parts by weight Chromium complex salt dye 2 parts by weight (Bontron S-34 manufactured by Orient Chemical Co., Ltd.) Low molecular weight polypropylene (Viscor 330P manufactured by Sanyo Kasei Kogyo Co., Ltd.) 2 parts by weight The mixture having the above composition was subjected to the same operation as in Example 1 to obtain toner particles. It was Tg of the toner is 62 ° C.,
The melting start temperature was 88 ° C and the flow softening point was 102 ° C. Comparative Example 5 Polyester resin of Comparative Synthesis Example 5 (P-5) 55 parts by weight Vinyl copolymer resin (A-2) 45 parts by weight Carbon black (MA-100 manufactured by Mitsubishi Chemical Corporation) 5 parts by weight Chromium complex salt dye (TRH manufactured by Hodogaya Chemical Co., Ltd.) 2 parts by weight Low molecular weight polypropylene (Viscole 330P manufactured by Sanyo Kasei Kogyo Co., Ltd.) 2 parts by weight The mixture having the above composition was treated in the same manner as in Example 1 to obtain toner particles. . Tg of the toner is 68 ° C.,
The melting start temperature was 92 ° C and the flow softening point was 112 ° C. Table 1 shows the resin compositions and physical properties of the toners obtained in Examples and Comparative Examples.

[0017]

[Table 1]

The following tests were carried out using the electrostatic image developing toners obtained in the above Examples and Comparative Examples. (1) Non-Offset Temperature Region and Non-Offset Temperature Range 5 parts by weight of the toner for developing an electrostatic image and 95 parts by weight of a ferrite carrier (DFC150S6 manufactured by Dowa Iron Powder Co., Ltd.) were mixed to prepare a two-component developer. Next, a plurality of belt-shaped unfixed images each having a length of 2 cm and a width of 5 cm were produced on an A4 transfer paper by using a commercially available copying machine (Z-133 manufactured by Sanyo Electric Co., Ltd.) using the developer. Then, a heat-fixing roll having a surface layer made of Teflon and a pressure-fixing roll having a surface layer made of silicone rubber are paired and rotated, and a roll pressure is 1 kg / cm ² and a roll speed is 200 mm / s.
The surface temperature of the heat-fixing roll was changed stepwise so that the toner image on the transfer paper having the unfixed image was fixed at each surface temperature. At this time, observe whether there is toner stain in the margin,
The temperature range where dirt does not occur is the non-offset temperature range,
The difference between the maximum value and the minimum value in the non-offset temperature region was defined as the non-offset temperature width. (2) Fixing Strength The surface temperature of the heat fixing roll of the fixing device was set to 130 ° C., and the toner image on the transfer paper on which the unfixed image was formed was fixed. Then, after measuring the image density of the formed fixed image using a reflection densitometer (RD-914 manufactured by Macbeth Co.), the fixed image was rubbed with a cotton pad, and then the image density was similarly measured. Was measured. The fixing strength was calculated from the obtained measured value by the following formula and used as an index of the low energy toner. The results are shown in Table 2.

[Equation 1] Fixing strength (%) = (image density of fixed image after rubbing / image density before rubbing) × 100

[0019]

[Table 2]

As is clear from the results of Table 2, the non-offset temperature range of the toner for developing an electrostatic charge image of the present invention does not cause offset from a low temperature to a high temperature, and the non-offset temperature range is 100 ° C. or more. Therefore, it was confirmed that a practically sufficient range was maintained. Also, 130
Since the fixing strength at a fixing temperature of 80 ° C. was 80% or more, which was a practically sufficient fixing strength, it was confirmed that the fixing ability was excellent at low temperature. Furthermore, the image density of the developed image was sufficient, and there was no fogging of the non-image portion, which was practically sufficient. On the other hand, in Comparative Examples 1 to 5, the non-offset temperature region was not obtained, and it was practically unusable. Further, in each of Comparative Examples 1 to 5, the carbon dispersion in the toner was poor, and white spots in the developing area and fog in the non-developing area were conspicuous and not practical. Also,
A continuous copy test of up to 10,000 sheets was conducted using each developer and the copying machine of the example in the above item (1). As a result, in all of the examples, the triboelectric charge amount measured by the blow-off triboelectric charge measuring device (manufactured by Toshiba Chemical Co., Ltd.) was changed at a value of −25 to −29 μc / g from the initial stage to 10000 sheets, and the image density was also changed. It maintained 1.4 or more in the process of continuous copying from the initial stage to 10000, and the non-image area fog measured by a color difference meter (Z-1001DP manufactured by Nippon Denshoku Co., Ltd.) was 0.6 or less, which is a practical problem. It was confirmed that there is no. Further, even if the toner was left to stand at 50 ° C. for 2 days, neither blocking nor caking was observed.

[0021]

The toner for developing an electrostatic image of the present invention has a sufficient non-offset temperature region, can be fixed at a low temperature, has excellent fixing strength, and has a sufficient image density. There is an effect that the number of sheets can be obtained. Therefore, when the electrostatic image developing toner of the present invention is applied to a copying machine, a printer, or the like, it is possible to reduce power consumption, and it is extremely possible to reduce the machine cost by lowering the pressure of the roll and increase the copying speed. It is valid.

Claims (7)

[Claims] 1. A toner for developing an electrostatic charge image, comprising a vinyl polymer graft polyester resin and a vinyl copolymer resin. 2. A vinyl polymer graft polyester resin comprising at least a diol component, a dicarboxylic acid component or a lower alkyl ester thereof or an acid anhydride thereof, and a vinyl macromonomer having a dihydroxyl group or a dicarboxyl group at one end. The toner for developing an electrostatic image according to claim 1, which is a resin obtained by the reaction of. 3. The electrostatic image development according to claim 1, wherein the content of the vinyl polymer in the vinyl polymer graft polyester resin is 1 to 50% by weight based on the total weight of the resin. For toner. 4. The molecular weight peak in the GPC chromatogram of the vinyl polymer graft polyester resin is
The toner for developing an electrostatic charge image according to claim 1, which is present in the range of 10 ^{3 to} 2 × 10 ⁴ . 5. The toner for developing an electrostatic image according to claim 1, wherein the melting start temperature of the vinyl polymer graft polyester resin is 50 to 110 ° C. 6. The electrostatic image developing toner according to claim 1, wherein the vinyl copolymer resin has a molecular weight peak in the GPC chromatogram of 10 ⁵ to 10 ⁷ . 7. The toner for developing an electrostatic image according to claim 1, wherein the content of the vinyl copolymer resin in the resin component is 1 to 50% by weight.