JPH0643688A - Electrostatic charge image developing toner - Google Patents

Abstract

PURPOSE:To obtain a low-temp. fixative toner without deteriorating the crushability, preservation stability and fixability by incorporating a resin consisting of a specified repeating unit into the toner. CONSTITUTION:This toner contains a resin consisting of a repeating unit shown by formula I. In the formula, R<1> is a 1-25C alkylene group having a straight chain or branched chain, R<2> is a styrenic polymer, X is a group shown by formula II, X<1> and X<2> are the group shown by formula II or III when X is directly coupled, X<1> is-O-where X is shown by formula II, X<2> is a group shown by formula IV, (y) and (z) are 0 or 1, and (m) and (n) are an integer of 1. The resin has a thermotropic liq. crystal property, the crystallinity is generally high, and the resin exhibits a thermosoftening behavior below the m.p. The resin is rapidly liquefied (melted), when further heated, the viscosity is lowered, and the temp. is decreased.

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 the fields of electrophotography, electrostatic recording and the like.

[0002]

2. Description of the Related Art In electrophotography or electrostatic recording, an electrostatic charge image is formed and then the electrostatic charge image is developed with toner fine particles in which a colorant is dispersed in a binder resin. Then, after the toner image is transferred onto the surface of the transfer material such as paper, it is fixed on the surface of the transfer material by heat, pressure, heat pressure or the like to perform copying or recording image. For fixing the toner image, a method of heating the toner image to a temperature at which the toner softens and at the same time applying pressure to fix the toner image on the surface of the transfer target material, that is, a toner image is formed between a pair of heating rolls and a pressure roll. A so-called thermal roll fixing method is generally used, in which the material to be transferred is inserted and heated and pressed to fix the material. This heat roll fixing method is an effective fixing method because it has high thermal efficiency, little heat dissipation, and quick fixing.

A conventional toner for developing an electrostatic charge image applied to such a heat roll fixing method has an Mn of 3000 to 1000.
No. 0 styrene-acrylic copolymer was used. However, when low temperature fixing due to the recent demand for low energy is carried out with the toner according to such a conventional technique, there is a problem that low temperature fixing, that is, low energy fixing cannot be performed due to the high softening point of the toner resin. It was Therefore, in order to solve these problems, it is necessary to lower the softening point of the toner, as disclosed in JP-A-59-228658 and JP-A-2-2519.
No. 71, various binder resins have been proposed.

However, the resins used for these toners can be fixed at a low temperature by lowering the softening temperature. However, the lowering of the softening temperature lowers the fluidity in the pulverizing step in toner production, or transport and storage. There is a problem of poor storage stability that causes aggregation of the toner, and there are none satisfying all of low energy fixing, fluidity and storage stability, and there is still a problem.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is an electrostatic charge image capable of low temperature fixing without impairing pulverizability, storage stability, and fixability. To provide a developing toner.

[0006]

As a result of intensive studies to solve the above problems, the present inventor has found that the binder constituting the toner contains a specific resin having thermotropic liquid crystallinity to reduce the Energy fixation is possible, and
The present invention has been accomplished by finding that pulverizability is good and storage stability is good. That is, the electrostatic image developing toner of the present invention is characterized by containing a resin comprising a repeating unit represented by the following general formula (I).

[Chemical 2]

In the present invention, the resin comprising the repeating unit represented by the general formula (I) can be produced by the following synthetic method, but the present invention is not limited thereto. (A) First step <Synthesis of the following general formula (II)>

[Chemical 3] By reacting 4,4'-biphenyl having a hydroxyl group at both ends with a halogen group at one end and an alkyl compound R having a hydroxyl group at the other end and having 25 or less carbon atoms, the compound represented by the general formula (II) can be easily obtained. Compounds can be synthesized. Examples of the alkyl compound used in the synthesis of the general formula (II) include 1-chloro-6-hydroxyhexane and 1-bromo-6-hydroxyhexane.
An alkyl compound having a halogen group at one end and a hydroxyl group at the other end and having a straight or branched chain having 1 to 25 carbon atoms can be mentioned, but it is not particularly limited. In this case, when the number of carbon atoms of the alkyl group exceeds 25, the melting point of the resin having thermotropic liquid crystallinity becomes too low and the resin easily aggregates, which is unfavorable in terms of pulverizability and storage stability.

(B) Second step <Synthesis of general formula (I) (when y = 0)>

[Chemical 4] When y = 0 in the general formula (I), that is, the resin used in the present invention represented by the general formula (III) is
(I) In the case of z = 0, the compound represented by the general formula (II) is polymerized using, for example, COCl ₂ or the like, and (ii) in the case of z = 1, the general formula (II) And the alkyl compound R ¹ having a hydroxyl group, a carboxylic acid group or an isocyanate group at both ends and having 25 or more carbon atoms
It can be obtained by copolymerizing and.

(C) Third Step <Synthesis of General Formula (I) (when y = 1)> When y = 1 in the above general formula (I), the resin used in the present invention has the general formula (III ) And a styrenic polymer R ² having a hydroxyl group capable of reacting with the terminal group of the general formula (III) at one end. Examples of the styrene-based polymer used here include polystyrene, styrene-acrylic copolymer, styrene-butadiene copolymer and the like, but are not particularly limited.

The resin comprising the repeating unit represented by the general formula (I) used in the present invention obtained as described above is
Has thermotropic liquid crystallinity, usually high crystallinity,
Although it exhibits a gentle thermal softening behavior up to the melting point, it has the property of rapidly liquefying (dissolving) when the temperature further rises, lowering the viscosity and lowering the temperature. Further, in the present invention, such a resin has an intrinsic viscosity of 0.2 to 30 measured at 30 ° C. in a dichloroacetic acid solvent having a concentration of 0.2 g / dl.
Those in the range of 3.0 dl / g are preferable. When the intrinsic viscosity exceeds 3.0 dl / g, the melting temperature becomes high and low-temperature fixing becomes difficult, and when it is 0.2 or less, it is too soft and blocking is likely to occur, which is not preferable.

The electrostatic charge image developing toner of the present invention may contain a colorant, a charge control agent, an offset preventive agent, other binder resin, a magnetic material and the like in the thermotropic liquid crystalline resin, if necessary. . In this case, as the colorant, carbon black, acetylene black, phthalocyanine blue, permanent brown FG, brilliant fast scarlet, pigment green B,
Examples thereof include Rhodamine-B base, Solvent Red 49, Solvent Red 146, Solvent Blue 35, and the like, and mixtures thereof. Usually, resin component 100
About 1 to 15 parts by weight is used with respect to parts by weight. The resin component in this case means a combination of the resin of the general formula (I) and other binder resin.

Examples of the charge control agent include alkylpyridium halides, organic sulfates, sulfonic acid compounds, distearyldimethylammonium methylsulfate and the like, and the addition amount of these is 0.1% with respect to 100 parts by weight of the resin component. About 1 to 15 parts by weight is used. Further, as the offset preventing agent, low molecular weight polypropylene, fatty acid ester wax, polyvalent carboxylic acid, metal salt of fatty acid and the like can be used. Other binder resins include acrylic resins, polycarbonate resins, polyester resins, polyurethane resins, polystyrene resins,
Alternatively, a copolymer of the constituent monomers of these resins can be used. Furthermore, examples of the magnetic substance include alloys and compounds exhibiting ferromagnetism such as ferrite and magnetite. The magnetic material has an average particle size of 0.1 to 0.1.
An amount of 40 to 70% by weight can be dispersed and used in the resin component in the form of fine particles of 1 μm.

The toner for developing an electrostatic image according to the present invention is prepared by adding necessary additives to a resin component, melt-kneading at a temperature equal to or higher than the melting point of the resin component, cooling, pulverizing, and further classifying. It can be produced by a so-called kneading and pulverizing method. It can also be manufactured by a manufacturing process of a toner by a polymerization method such as suspension polymerization. The toner for developing an electrostatic image of the present invention has a particle diameter of about 5 to 25 μm, and for fixing on a transfer material, a contact or non-contact method such as flash fixing, infrared heat fixing, heating oven fixing, and heat roll fixing. Can be done at.

[0014]

The present invention is described in detail below with reference to examples, but the present invention is not limited thereto. Example 1 (A) Synthesis of Resin (IIIs) of General Formula (I) 350 ml of N, N-dimethylformamide (DMF) contains 93.1 g (0.5%) of 4,4′-dihydroxydiphenyl.
Mol) and 6-chlorohexanol 152
g (11 mol) and calcium carbonate 159 g (1.15
Mol) was added and the mixture was refluxed for 24 hours and then poured into a 5% aqueous hydrochloric acid solution to obtain 6,6 ′-(4,4′-biphenylenedioxy).
Dihexanol (Is) was precipitated. This precipitate is D
It was recrystallized from a mixed solvent of MF and water. The melting point of this compound was 171.5 to 173.0 ° C, and the yield was about 80%. Next, a solution prepared by dissolving 37.1 g (0.35 mol) of 1,6-hexadiol in 70 ml of pyridine was cooled to 5 ° C., and 120.4 g (0.77 mol) of phenoxycarbonyl chloride was added to this solution. The solution was dropped in the form of liquid droplets and further stirred for 4 hours to cause a reaction. The reaction solution was poured into a large amount of 5% hydrochloric acid aqueous solution to precipitate a reactive substance, which was washed with water to obtain 87.7 g of hexyl diphenyl dicarbonate (II
s) (yield about 70%) was obtained. The melting point of this compound is 88.
It was 5-90.0 degreeC. 77.3 g (0.2 mol) of the above compound Is thus obtained and IIs 78.8
g (0.22 mol) and 1.4 g of zinc acetate as a catalyst
180 to 19 while coexisting with stirring under a nitrogen atmosphere
The mixture was reacted at 0 ° C. for 2 hours, then depressurized to 12 to 13 torr and depressurized to 190 to 200 ° C. for 1 hour, and further depressurized to 2 torr to 200 to 205 ° C. for 30 minutes to prepare a compound represented by the following formula (III
Resin (IIIs) represented by s) used in the present invention was obtained.

[Chemical 5] The resin has an intrinsic viscosity of 0.52 dl / g (in a dichloroacetic acid solvent, a concentration of 0.2 g / dl, 30 ° C., the same applies hereinafter), an average molecular weight of 8300 (in terms of polystyrene) and a yield of about 92.
%Met. Identification was performed by elemental analysis, and C: 74.
9, H: 7.00 (calculated values are C: 76.1, H: 6.9
It was 4). The resin exhibited liquid crystallinity at 110 ° C. (Olympus Optical polarization microscope POM)

(B) Preparation of toner for developing electrostatic image: Resin (IIIs) obtained in (A) above 93 parts by weight Carbon black 7 parts by weight After mixing the above components in a ball mill, pressurization The mixture was kneaded in a kneader for 30 minutes, cooled, coarsely pulverized, and then finely pulverized by a jet pulverizer to prepare an electrostatic image developing toner of the present invention having an average particle diameter of 12 μm.

Example 2 30.1 g (4 mmol) of the resin (IIIs) obtained in Example 1
And 6 g (1 mmol) of 1,2-dihydroxyethane polystyrene having a hydroxyl group at one end (manufactured by Towa Synthetic Chemical Industry Co., Ltd., average molecular weight: about 6000) under nitrogen atmosphere in the presence of 0.7 g of zinc acetate catalyst, 180 Resin (IVs) represented by the following formula (IVs) by reacting at ˜190 ° C. for 2 hours, further under 12 to 13 Torr at 190 to 200 ° C. for 30 minutes, and further at 2 Torr at 200 to 205 ° C. for 30 minutes. Got The obtained resin had an intrinsic viscosity of 0.67 dl / g and an average molecular weight of 22,100. As a result of FTIR identification of this resin, the absorption corresponding to the carbonyl group was around 1730 cm ^{−1 and} the absorption corresponding to the unsubstituted phenyl ring was 700 and 750.
It was observed around cm ^-1 . The temperature at which the resin exhibits liquid crystallinity was 124 ° C.

[Chemical 6] (However, PS is polystyrene and the molar ratio of LC polycarbonate and PS is 4: 1.) After 93 parts by weight of the resin (IVs) obtained above and 7 parts by weight of carbon black are mixed in a ball mill, Knead for 30 minutes with a pressure kneader,
After cooling, finely pulverize with a jet pulverizer to obtain an average particle size of 12 μm.
A toner for developing an electrostatic image according to the present invention was prepared.

Example 3 Exactly the same as Example 2, except that the resin (IIIs) was changed from 30.1 g to 22.6 g (3 mmol) and the resin (IVs) was changed from 6 g to 12 g (2 mmol). The resin (Vs) represented by the above formula (IVs) used in the present invention was obtained by the method. In the resin (Vs), the molar ratio of LC polycarbonate to PS is 3: 2. The resin had an intrinsic viscosity of 0.72 dl / g and an average molecular weight of 25,000. In addition, the result of identification by elemental analysis of the resin is C: 7.
5.5, H: 7.89 (calculated values are C: 76.1, H:
7.94), and liquid crystallinity was observed at 122 ° C. A mixture of 93 parts by weight of the resin (Vs) obtained above and 7 parts by weight of carbon black was treated in the same manner as in Example 2 to prepare an electrostatic image developing toner of the present invention having an average particle size of 12 μm.

Example 4 Except that the resin (IIIs) was changed from 30.1 g to 37.7 g (5 mmol) and the resin (IVs) was changed from 6 g to 30 g (5 mmol) in Example 2, Resins (VI) represented by the above formula (IVs) used in the present invention in exactly the same manner.
s) was obtained. In the resin (VIs), the molar ratio of LC polycarbonate to PS is 1: 1. The resin has an intrinsic viscosity of 0.55 dl / g and an average molecular weight of 14,10.
0, and liquid crystallinity was observed at 122 ° C. 93 parts by weight of the resin (VIs) obtained above and 7 parts by weight of carbon black were mixed in a ball mill, kneaded in a pressure kneader for 30 minutes, cooled, and finely ground in a jet grinder to obtain an average particle size of 12
A μm toner of the present invention for developing an electrostatic image was prepared.

Comparative Example 1 Polystyrene acrylic copolymer (TTR manufactured by Fujikura Kasei Co., molecular weight of about 130,000) 93 parts by weight Carbon black 7 parts by weight After mixing the composition having the above composition by a ball mill, 30 by a pressure kneader. After kneading, the mixture was cooled and then finely pulverized with a jet pulverizer to obtain a comparative electrostatic image developing toner having an average particle diameter of 12 μm.

Table 1 collectively shows the evaluation results of the toners for developing electrostatic images obtained in Examples 1 to 4 and Comparative Example 1.

[Table 1] The evaluation method is as follows. Crushability: Jet crusher (made by Nippon New Mac Co.,
I-10) was used to evaluate its grindability. ◯: Very good, Δ: Slightly bad, x: Cannot be crushed Storage stability: Temperature of prepared toner: 50 ° C., humidity: 8
After being left for 8 hours in a 0% environment, its fluidity was examined. ◯: No change, Δ: Slightly worse, x:
Agglomeration is observed Fixing temperature: A developer prepared by mixing 5 parts by weight of toner with 95 parts by weight of a magnetic carrier (F141-2535 manufactured by Powdertech Co., Ltd.) has a sufficient fixing property for practical use measured by the method described below. The minimum temperature required for fixing was defined as the fixing temperature. Specifically, a commercially available copying machine (SF-9800, manufactured by Sharp Corp.) was used so that the surface temperature of the heat roll of this copying machine could be freely changed, and the accompanying offset prevention sleeve was removed. The fixing temperature was measured by loading the developer into a copying machine having only a fixing roll made of silicone rubber and a Teflon-coated heat roll. The image density is 1.0 to 1.1 when the optical density of the Macbeth reflection densitometer is 1.0 to 1.1.
In the solid black part, the toner adhered to the cellophane tape was set as a limit at which there was no practical problem. As is clear from Table 1, it was confirmed that the toner for developing an electrostatic image of the present invention is capable of low energy fixing without impairing pulverizability, storage stability and fixability.

[0021]

INDUSTRIAL APPLICABILITY The present invention can provide a toner for developing an electrostatic charge image, which can be fixed at a low energy at a lower temperature without deteriorating its pulverizability, storage stability and fixability.

Claims (1)

[Claims] 1. A toner for developing an electrostatic charge image, which comprises a resin comprising a repeating unit represented by the following general formula (I). [Chemical 1]