JPH0316023B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a developer composition for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, and the like. [Prior art and problems] As a conventional electrophotographic method, US Patent No. 2297691
As stated in the specification of No. 2357809, etc.
An electrical latent image is formed by uniformly charging the photoconductive insulating layer, then exposing the layer to light and dissipating the charge on the exposed portions, and then applying toner to the latent image. After the visible image is transferred to a transfer material such as transfer paper (transfer process), heat and pressure are applied. Alternatively, it consists of a step of permanently fixing (fixing step) by another suitable fixing method. As described above, the toner must have the functions required not only in the development process but also in each process such as the transfer process and the fixing process. Generally, toner is subjected to mechanical frictional force due to shearing force and impact force during mechanical operation in a developing device, and deteriorates while copying several thousand to tens of thousands of sheets.
To prevent such toner deterioration, it is best to use a strong resin with a large molecular weight that can withstand mechanical friction, but these resins generally have a high softening point and are suitable for non-contact fixing methods such as oven fixing and infrared fixing. With radiant fixing, the thermal efficiency is poor, so fixing is not sufficient.Also, with the contact fixing method, which has good thermal efficiency, even in the widely used heat roller fixing method, the temperature of the heat roller must be adjusted to ensure sufficient fixing. This not only causes problems such as deterioration of the fixing device, curling of paper, and increased energy consumption, but also causes a significant drop in production efficiency when producing toner by pulverizing such resins. do. Therefore, it is not possible to use a binder resin whose polymerization degree and even softening point are too high. On the other hand, in the heat roller fixing method, the heating roller surface and the toner image surface of the sheet to be fixed are in pressure contact, so the thermal efficiency is extremely high and it is widely used from low speeds to high speeds. When doing so, so-called offset development is likely to occur, in which the toner adheres to the surface of the heating roller and is transferred to subsequent transfer paper or the like. To prevent this phenomenon, the surface of the heating roller is treated with a material with excellent mold release properties such as fluorine-based resin, and in addition, a mold release agent such as silicone oil is applied to the surface of the heating roller to completely prevent the offset phenomenon. are doing. However, the method of applying silicone oil or the like is not preferable because it not only increases the size of the fixing device and increases the cost, but also makes it complicated, which can easily cause trouble. Furthermore, as described in Japanese Patent Publication No. 55-6895 and Japanese Patent Application Laid-Open No. 56-98202, there is a method to improve the offset phenomenon by widening the molecular weight distribution width of the binder resin, but the degree of polymerization of the resin increases and the fixation becomes difficult. The temperature also needs to be high. As a further improved method, Special Publication No. 57-493,
As described in JP-A-50-44836 and JP-A-57-37353, there is a method of improving the offset phenomenon by making the resin asymmetrical and crosslinking, but the fixing point has not been improved. Generally, the minimum fusing temperature is between cold offset and hot offset, so the usable temperature range is
It is between the minimum fixing temperature and hot offset, and by lowering the minimum fixing temperature as much as possible and raising the minimum hot offset temperature as much as possible, it is possible to lower the usable fixing temperature and expand the usable temperature range, which saves energy. , high-speed fixing, and prevents paper from curling. In addition, since double-sided copying can be performed without trouble, copying machines have become more intelligent, and the temperature control of the fixing device has become more accurate.
There are many advantages such as relaxing the tolerance range. Therefore, resins and toners with good fixing properties and offset resistance are always desired. In general, polyester resins and styrene resins are often used as resins, and it is desirable to use styrene resins economically, but styrene resins inherently have a high minimum fixing temperature, and the resin composition and wax Improvements made through the addition of compounds naturally had their limits. The present invention was made to meet these demands, and its purpose is to provide a developer that can prevent offset without applying an anti-offset liquid in a heat roller fixing system and that can fix at a lower fixing temperature. It is about providing. Another object of the present invention is to provide a developer which can prevent offset without adding an offset preventive agent in a heat roller fixing system and which can be fixed at a lower fixing temperature. Another object of the present invention is to provide a developer that has good fluidity, does not cause blocking, and has a long life (hard to deteriorate). Another object of the present invention is to improve kneading properties during developer production.
The objective is to provide a developer with good pulverizability. [Means for Solving the Problems] In order to achieve the above-mentioned object, the present inventors conducted intensive research and arrived at the present invention. That is, the present invention provides an electrophotographic developer composition containing a binder resin and a colorant as main components, wherein the main components of the binder resin are (a) styrene and/or a styrene derivative, and (b) methacrylate. When polymerizing with one or more monomers selected from acids, acrylic acid and esters thereof, (c) a polymer obtained by reacting a divalent or higher carboxylic acid having 7 to 40 carbon atoms; Component (B) contains at least one ester of acrylic acid or methacrylic acid having a small amount of (di)hydroxyl group or epoxy group in an amount equal to or more than the amount of component (C), and (c)
This relates to an electrophotographic developer composition characterized in that the content of the component is 0.05 to 10% by weight based on the total amount of monomers. The electrophotographic developer composition of the present invention is preferably one in which the binder resin has a softening point on a Koka type flow tester of 100 to 160°C and a glass transition temperature of 50°C or higher, and more preferable is one described above ( The compound c) is an acid represented by the following general formula, an acid anhydride thereof, or a lower alkyl ester thereof. (In the formula, R is an alkyl group, alkenyl group, alkylene group, or alkenylene group having 5 to 30 carbon atoms and having one or more side chains having 3 or more carbon atoms, and n is an integer of 0 or 1) In the present invention Component (C) may be reacted with component (B) before polymerization, or may be reacted after polymerization of component (A) and component (B), or during polymerization. It may be reacted. The polymerization reaction mainly proceeds by generally known vinyl polymerization, in which case a polymerization initiator such as a peroxide or an azo compound is used, and reaction conditions are appropriately selected depending on the monomers, initiator, etc. used. Examples of styrene or styrene derivatives (a) in the present invention include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene,
2,4-dimethylstyrene, p-n-butylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-
n-nonylstyrene, p-n-decylstyrene,
Examples include p-n-dodecylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, and others. The proportion of component (a) is preferably 75 to 90% by weight of the total amount of monomers, as exemplified in the examples. Examples of (b) methacrylic acid, acrylic acid or ester thereof include acrylic acid, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-acrylate
Butyl, isobutyl acrylate, tert acrylate
-Butyl, amyl acrylate, cyclohexyl acrylate, n-octyl acrylate, isooctyl acrylate, decyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, methoxyethyl acrylate, 2-hydroxyethyl acrylate , hydroxypropyl acrylate, glycidyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, α
- Methyl chloroacrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate,
n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, amyl methacrylate, cyclohexyl methacrylate, n-octyl methacrylate, isooctyl methacrylate, decyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, methacrylic acid Examples include stearyl, methoxyethyl methacrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, glycidyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and others. Hydroxyethyl acrylate in the component (b) above,
Hydroxypropyl acrylate, glycidyl acrylate, 2-hydroxyethyl methacrylate, and glycidyl methacrylate are the above-mentioned esters of acrylic acid or methacrylic acid having a hydroxyl group or an epoxy group, which is the component (d) above.
It is contained in an amount equal to or more than the mole of component (c). In the present invention, the component (c) above reacts with the hydroxyl group or epoxy group of the component (d) to form an ester bond, and a long chain soft segment is created in the resin produced by the polymerization reaction. It is presumed that the esters are introduced and intermolecular crosslinks are generated by the esters. Component (iii) can be easily obtained by a known method such as a reaction between a divalent unsaturated carboxylic acid such as maleic acid and an unsaturated hydrocarbon, or a subsequent hydrogenation reaction.
Examples of the divalent component (c) include isobutenylsuccinic acid, n-dodecenylsuccinic acid, isododecenylsuccinic acid, n-octenylsuccinic acid, isooctenylsuccinic acid, isobutylsuccinic acid, n-dodecylsuccinic acid, Examples include isododecylsuccinic acid, n-octylsuccinic acid, isooctylsuccinic acid, and acid anhydrides or lower alkyl esters thereof. As tetravalent components, (1) 4-neopentylidenyl-1,2,6,7-
Heptanetetracarboxylic acid (2) 4-Neopentyl-1,2,6,7-heptene (4)-tetracarboxylic acid (3) 3-Methyl-4-heptenyl-1,2,5,
6-hexanetetracarboxylic acid (4) 3-methyl-3-heptyl-5-methyl-
1,2,6,7-heptene(4)-tetracarboxylic acid(5) 3-nonyl-4-methylidenyl-1,2,
5,6-hexanetetracarboxylic acid (6) 3-decylidenyl-1,2,5,6-hexanetetracarboxylic acid (7) 3-nonyl-1,2,6,7-heptene (4)-
Tetracarboxylic acid (8) 3-decenyl-1,2,5,6-hexanetetracarboxylic acid (9) 3-butyl-3-ethylenyl-1,2,5,
6-hexanetetracarboxylic acid (10) 3-methyl-4-butylidenyl-1,2,
6,7-heptanetetracarboxylic acid (11) 3-methyl-4-butyl-1,2,6,7-
Heptene(4)-tetracarboxylic acid(12) 3-methyl-5-octyl-1,2,6,7
-heptene(4)-tetracarboxylic acid and the like. The structural formulas of these compounds are shown below. For convenience, all are shown in the form of acid anhydrides.

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〔Example〕

Examples of the invention will be described below, but the invention is not limited to these examples. It should be noted that all composition ratios shown in Examples are expressed in parts by weight. Example 1 Xylene was added to a reactor equipped with a stirring device, a nitrogen inlet tube, a thermometer, a reflux condenser tube, and a dropping funnel.
500 parts of indodecyl succinic acid and 11.5 parts of 2-hydroxyethyl acrylate were charged, and the temperature was lowered.
Adjust the temperature to 80°C, and stir at the same temperature for 1 hour under a nitrogen stream. 820 parts of styrene, 130 parts of 2-ethylhexyl acrylate, 2-acrylic acid under a nitrogen stream
11.5 parts of hydroxyethyl and 10 parts of benzoyl peroxide
The mixed solution of 1 part was polymerized dropwise over 4 hours. After aging at the same temperature for 10 hours after the dropwise addition, the temperature was gradually raised to 210°C while the pressure was reduced to 2 mmHg, the xylene was distilled off, and the molten resin was taken out into a stainless steel vat, left to cool, and pulverized to form a powder. A resin (Koka flow tester softening point: 125.2°C, Tg: 60.3°C) was obtained. This softening point was determined using a ^1cm3 sample using a Koka type flow tester (manufactured by Shimadzu Corporation) at a heating rate of 6℃/
20Kg/cm ³ by plunger while heating in minutes.
By applying a load of
When the height of the curve is h, the temperature corresponding to h/2 is defined as the softening point. After mixing 93 parts of the resin and 7 parts of carbon black (Regal 400R manufactured by Kabot Corporation) in a ball mill,
The mixture was kneaded using hot rolls, cooled, coarsely pulverized using a hammer mill, further finely pulverized using a jet mill, and classified to obtain a toner having an average particle size of 13.5 μm. The obtained toner was mixed with carrier iron powder (manufactured by Nippon Tetsuko Co., Ltd.; EFV20).
0/300) and measured the amount of charge using a blow-off measuring device, it was -19 μc/g. A developer was prepared by mixing 91 g of the toner with 1209 g of carrier iron powder, and a commercially available electrophotographic copying machine (the photoreceptor is amorphous selenium, the fixing roller has a diameter of 60 mm)
mm, rotation speed is 255 mm/sec, the temperature of the heat roller in the fixing device is variable and the oil application device is removed), and there was no background smearing, bleeding, or missing black solid areas. A clear image was obtained. When the fixing temperature was controlled between 140℃ and 220℃ and the image fixation and offset properties were evaluated, the result was 145.
It was sufficiently fixed at ℃, and no hot offset occurred. When images were printed up to 50,000 sheets, clear images were obtained with no background fogging or missing solid black areas. The minimum fixing temperature here is 15mm x 7.5mm on the bottom.
A load of 500 g was placed on a sand eraser, and the image fixed through the fixing machine was rubbed back and forth 5 times. The optical reflection density was measured using a Macbeth reflection densitometer before and after rubbing, and the fixing rate was determined by the following definition. This refers to the temperature of the fixing roller when it exceeds 70%. Fixing rate = Image density after rubbing / Image density before rubbing Example 2 In the reactor of Example 1, 500 parts of xylene, 20 parts of 3-decenyl-1,2,5,6-hexanetetracarboxylic acid, and 6 parts of 2-hydroxyethyl methacrylate was charged, the temperature was adjusted to 80°C, and the mixture was stirred at the same temperature for 1 hour under a nitrogen stream. α− under nitrogen flow
890 parts of methylstyrene, 74 parts of butyl acrylate,
A mixture of 10 parts of 2-hydroxyethyl methacrylate and 15 parts of lauroyl peroxide is dropwise polymerized over 4 hours. After completion of dripping, after aging at the same temperature for 10 hours,
While gradually raising the temperature to 210℃, the pressure was reduced to 2mmHg, xylene was distilled off, the molten resin was taken out into a stainless steel vat, allowed to cool, pulverized, and powdered resin (Koka flow tester softening point 121.0℃) ,
Tg61.2℃) was obtained. 93 parts of the resin and 7 parts of carbon black (Regal 400R, manufactured by Kayabot Co., Ltd.) were mixed in a ball mill, then kneaded, crushed, and classified to obtain a toner having an average particle size of 13.3 μm. The amount of charge of the obtained toner was -21μc/
It was hot at g. A developer was prepared by mixing 91 g of the toner with 1209 g of carrier iron powder, and an image was produced using the same evaluation machine as in Example 1. A clear image was obtained with no background smudges, bleeding, or missing solid black areas. Ta. When the fixing temperature of the fixing device was controlled and the image fixability and offset properties were evaluated, the image was fixed at 150° C. and no hot offset occurred. When images were printed up to 50,000 sheets, clear images were obtained with no background fogging or missing solid black areas. Example 3 In the reactor of Example 1, 500 parts of xylene, 30 parts of isododecenylsuccinic acid, and glycidyl methacrylate were added.
15 parts, 780 parts of styrene, 35 parts of methyl methacrylate,
Using 140 parts of butyl acrylate and 20 parts of α,α'-azobisdimethylvaleronitrile, a powdered resin (Koka flow tester softening point 126.4°C Tg 63.1) was prepared in the same manner as in Example 1. °C) was obtained. 93 parts of the resin and 7 parts of carbon black (Regal 400R, manufactured by Kabot Corporation) were mixed in a ball mill, then kneaded, pulverized, and classified to obtain a toner having an average particle size of 12.9 μm. Charge amount of the obtained toner - 18μc/g
It was hot. A developer was prepared by mixing 91 g of the toner with 1209 g of carrier iron powder, and an image was produced using the same evaluation machine as in Example 1. A clear image was obtained without background smearing, bleeding, or missing black solid areas. Obtained. Controls the fixing temperature of the fixing device to improve image fixability,
When the offset property was evaluated, it was fixed at 146°C and no hot offset occurred. When images were printed up to 50,000 sheets, clear images were obtained with no background fogging or missing solid black areas. Example 4 In the reactor of Example 1, 500 parts of xylene, 40 parts of octylsuccinic acid, 820 parts of styrene, 20 parts of dimethylaminoethyl methacrylate, 20 parts of glycidyl methacrylate, 100 parts of lauryl methacrylate, and α,
Using 15 parts of α′-azobisisobutyronitrile,
A powdered resin (softening point of Koka flow tester: 124.5°C, Tg: 60.5) was obtained in the same manner as in Example 1. 93 parts of the resin and 7 parts of carbon black (Regal 400R, manufactured by Kyaboru Co., Ltd.) were mixed in a ball mill, then kneaded, pulverized, and classified to obtain a toner with an average particle size of 13.0 μm. The amount of charge of the obtained toner is +20μc/
It was hot at g. A developer was prepared by mixing 91 g of the toner with 1209 g of carrier iron powder, and a commercially available electrophotographic copying machine (the photoreceptor is an organic photoconductor, the fixing roller has a diameter of 60 mm, the rotation speed is 255 mm/sec, and the heat in the fixing device) (Roller temperature variable and oil applicator removed)
When the image was produced using the following method, a clear image was obtained with no background smudges, smearing, or missing solid black areas. When we controlled the fixing temperature of the fixing device and evaluated the image fixing and offset properties, we found that the result was 149.
It was fixed at ℃ and no hot offset occurred. When images were printed up to 50,000 sheets, clear images were obtained with no background fogging or missing solid black areas. Comparatively 1 Using the reactor of Example 1, a mixture of 830 parts of styrene, 170 parts of 2-ethylhexyl acrylate, and 15 parts of benzoyl peroxide was added dropwise to 500 parts of xylene at 80°C over 4 hours, and then the same solution was added. Aged for 10 hours at temperature. Thereafter, xylene was distilled off by the method of Example 1, and a powdered resin (softening point: 130.5° C., Tg: 62.0° C. using a Koka flow tester) was obtained after extraction and pulverization. A toner (charge amount was -18 μc/g) was made using the resin in exactly the same manner as in Example 1, a developer was prepared, and an image was produced using the same evaluation machine as in Example 1. Clear images were obtained with no background smudges, smearing, or missing solid black areas. When the fixing temperature of the fixing device was controlled at 140 DEG C. to 220 DEG C. and the image fixability and offset properties were evaluated, the image was fixed at 175 DEG C., but offset occurred at all temperatures from 140 DEG C. to 220 DEG C. Comparative Example 2 Using the reactor of Example 1, 850 parts of styrene and n-butyl acrylate were mixed in 500 parts of xylene at 80°C.
A mixed solution of 140 parts of divinylbenzene, 15 parts of divinylbenzene, and 15 parts of lauroyl peroxide was added dropwise over 4 hours, and after aging at the same temperature for 10 hours, the xylene was distilled off using the method of Example 1, extracted, and pulverized to form a powder. A resin (softening point: 131.0°C, Tg: 62.2°C using Koka flow tester) was obtained.
A toner (charge amount was -18.5 μc/g) was prepared using the resin in exactly the same manner as in Example 1, a developer was prepared, and an image was produced using the same evaluation machine as in Example 1. Clear images were obtained with no background smudges, smearing, or missing solid black areas. When the fixing temperature of the fixing device was controlled and the image fixability and offset properties were evaluated, no hot offset occurred from 140°C to 220°C, but the fixing temperature was 195°C.

Claims (1)

[Scope of Claims] 1. An electrophotographic developer composition containing a binder resin and a colorant as main components, wherein the main components of the binder resin are (a) styrene and/or a styrene derivative; ) When polymerizing with one or more monomers selected from methacrylic acid, acrylic acid and esters thereof, (c) a monomer having 7 carbon atoms represented by the following general formula;
~40 carboxylic acids or their acid anhydrides or their lower alkyl esters (In the formula, R is an alkyl group having 5 to 30 carbon atoms having one or more side chains having 3 or more carbon atoms,
(representing an alkylene group, an alkenylene group, or an alkenyl group, and n is an integer of 0 or 1), wherein 1) the component (b) above contains at least one type of ( D)
An ester of acrylic acid or methacrylic acid having a hydroxyl group or an epoxyl group is contained in an amount equal to or more than the mole of the component (c) above, and 2) the content of the component (a) above is based on the total amount of monomers. hand
75 to 90% by weight, and 3) The content of the component (c) above is based on the total amount of monomers.
An electrophotographic developer composition characterized in that the content is 0.05 to 100% by weight. 2. The electrophotographic developer composition according to claim 1, wherein the resin has a softening temperature of 100 to 160°C as measured by a Koka type flow tester and a glass transition temperature of 50°C or higher.