JPS60233659A - Electrophotographic dry developer composition - Google Patents

Abstract

PURPOSE:To prevent offset in a heat roller fixing system without adding an offset inhibitor and to enable fixing at low fixing temp. by using a specified binder resin for the component of a developer. CONSTITUTION:The binder resin is composed of structural units of (a) styrene or styrene deriv., such as m-methylstyrene, as the main skeleton of the resin, (b) (meth)acrylic acid or its ester, such as methyl acrylate, for controlling the thermal property, such as softening point, and triboelectricity of the resin, and (c) a unit having 7-30C, and >=1 COOH, and >=1 unsaturated bond for changing the properties of the polymer so as to make it possible to lower the fixing temp. and to enhance offset resistance. The addition of the structural unit (c) in an amt. of 0.05-10wt% of the total wt. of (a)+(b) permits low temp. fixability and storage stability to be ensured.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a binder resin and a developer composition used for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, etc. It is.

[Conventional technology and problems]

Conventional electrophotographic methods include, as described in U.S. Pat. No. 2,297,691, U.S. Pat.
The photoconductive insulating layer is uniformly charged, the layer is then exposed to light, and the charge on the exposed portions is dissipated to form an electrical latent image, which is then injected with a color called toner. The resulting visible image is visualized by attaching fine powder with an electric charge (developing process), and the resulting visible image is transferred to a transfer material such as transfer paper (transfer process).

It consists of a step of permanently fixing (fixing step 11) using heat, pressure or other suitable fixing methods.

In this way, toner is used not only in the development process.

It must have the functions required in each step of the transfer process and 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 during copying of tens to tens of thousands of sheets. To prevent such toner deterioration, a strong resin with a large molecular weight that can withstand mechanical friction force can be used, but these resins generally have a high softening point and are not suitable for oven fixing, which is a non-contact fixing method.

Radiant fixing using infrared rays has poor thermal efficiency, so fixing cannot be performed sufficiently, and contact fixing has good thermal efficiency. It becomes necessary to raise the temperature of the resin, which not only causes problems such as deterioration of the fixing device, curling of paper, and increased energy consumption, but also reduces production efficiency when producing toner by pulverizing such resins. Significantly decreased. For that reason.

A binder resin (binding resin) with a high degree of polymerization and a high softening point cannot be used.

One roller fixing method has extremely good thermal efficiency because the surface of the heating roller and the toner image surface of the sheet to be fixed are in pressure contact1, and it is widely used from low speeds to high speeds. When the toner comes into contact with the heating roller, the toner adheres to the surface of the heating roller and is transferred to a subsequent transfer paper or the like. A so-called offset phenomenon is likely to occur. 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 spraying silicone oil etc.
This is not preferable because the fixing device becomes large and costly, and it becomes a double track, which tends to cause trouble.

Also, Special Publication No. 1982-6895, q# Kaisho 56-98202
As described in the above publication, there is a method of improving the offset phenomenon by widening the molecular weight distribution width of the binder resin, but since the degree of polymerization of the resin is high, it is necessary to increase the fixing temperature.

As a further improved method, as described in Japanese Patent Publication No. 57-493, Japanese Patent Application Laid-open No. 50-44856, and Japanese Patent Application Publication No. 57-37555, there is a method of improving the offset phenomenon by making the resin asymmetrical and crosslinking it. However, the retention point has not improved.

Generally, the minimum fusing temperature is between cold offset and hot offset, so the usable temperature range is between the minimum fusing temperature and hot offset. By raising the temperature as much as possible, the fixing temperature used can be lowered, and the usable temperature range can be widened, resulting in energy savings, high-speed fixing, and prevention of curling of the paper. In addition, since double-sided copying can be performed without trouble, there are many advantages such as increased intelligence in copying machines, precision in temperature control of the fixing device, and relaxed tolerances.

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 although it is desirable to use styrene resins economically, styrene resins inherently have a high minimum fixing temperature, and the resin composition and wax There were naturally limits to the improvement that could be made by adding such substances.

[Failure to solve the problem]

The present invention has been made to meet these demands, and its purpose is to prevent offset without applying an anti-offset liquid in a heat roller fixing method, and to achieve a result that can be fixed at a lower fixing temperature. Our objective is to provide adhesive resins and developers.

Another object of the present invention is to provide a binding resin and a developer that can prevent offset without adding an offset inhibitor in a heat roller fixing system and can fix at a lower fixing temperature.

Another object of the present invention is to provide a binding resin and a developer that have good fluidity, do not cause blocking, and have a long life (hard to deteriorate).

The present inventors have arrived at the present invention as a result of intensive research to achieve the above object.

That is, 1 the present invention provides (a) styrene and/or styrene derivatives, and (b) at least one type of (meth)acrylic acid or its ester, (c) one or more carboxyl groups and one or more unsaturations in the molecule. Has a bond and has 7 or more carbon atoms
A binding resin having an @-sign consisting of a resin copolymerized with 0.05 to 10% by weight of the compound No. 30 added to the total amount of (a) and (b) above, and the binding resin. The present invention provides a dry developer composition for electrophotography, which contains a binder resin as a main component, and a colorant as a main component.

Preferred binding resins for the present invention are those having a softening point of N100 to 160°C using a Koka type flow tester.

[Effect]

Examples of the styrene or styrene derivative (a) in the present invention include styrene, 0-methylstyrene, m
-Methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, z, a-dimethylstyrene% p-n-butylstyrene, p-tert-butylstyrene, p-n-hexylstyrene* p- "-Octylstyrene %P-"-nonylstyrenes p-n-decylstyrene%T'-n-dodecylstyrene, p-methoxystyrene, p-phenylstyrene, p-/lorstyrene%3.4-dichlor Examples include styrene.

(B) Examples of (meth)acrylic acid or its ester include acrylic acid, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, and tert acrylate. -Butyl, amyl acrylate, cyclohexyl acrylate, n-octyl acrylate, isooctyl acrylate, decyl acrylate, acrylic lauryl, 2-ethylhexyl acrylate, stearyl acrylate, methoxyethyl acrylate, acrylic acid 2
-Hydroxyethyl.

glycidyl acrylate, 2-chloroethyl acrylate,
Phenyl acrylate, methyl α-chloroacrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, methacrylic@tert-butyl, methacrylic acid amyl, cyclohexyl methacrylate, n-butyl methacrylate, isooctyl methacrylate, decyl methacrylate,
Examples include lauryl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, methoxyethyl methacrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, etc. .

Component (c) is a compound that has one or more carboxyl group and one or more unsaturated bond in the molecule and has 7 to 30 carbon atoms.The property of the polymer may be modified to meet the purpose of the present invention. Such a chemical structure is sufficient because it can be changed, but such compounds can be easily converted by known methods such as the reaction of unsaturated carboxylic acids such as maleic acid, acrylic acid, and methacrylic acid with unsaturated hydrocarbons. can get.

Preferred as component (c) are alkenyl succinic acids or their acid anhydrides; examples of alkenyl succinic acids include n-dodecenyl succinic acid, isododecenyl succinic acid, n-octenyl succinic acid, isooctenyl succinic acid, and their Examples include acid anhydrides.

Among the components constituting the binding resin according to the present invention.

(a) Styrene or styrene derivative forms the main skeleton of the resin, and (b) (meth)acrylic acid or its ester is used to adjust the thermal properties such as the softening point of the resin, determine the charge, and control the amount of charge. The compound (c) becomes a component that improves the minimum fixing temperature and offset resistance. Among these components, the ratio of (()) styrene or styrene derivative to (b) (meth)acrylic acid or its ester is preferably 20:80 to 95:5 (weight ratio), and (c) The compound is added in an amount of 0.05 to 10% by weight based on the total amount of (a) and (b).If the amount of the compound (c) is less than 0.05% by weight, fixing properties cannot be improved; Furthermore, if the content exceeds 10% by weight, the storage stability of the toner will deteriorate.

Further, the softening point of the binder resin used in the developer composition of the present invention is preferably 100 to 160°C using a Koka type flow tester; if it is too low, the offset resistance will be insufficient, and if it is too high, the fixing property will be poor. It becomes insufficient.

The method for producing the binding resin of the present invention is carried out by well-known addition polymerization reactions such as free radical, anionic, and cationic polymerization methods.

Coloring agents used in the present invention include carbon black, acetylene black, phthalocyanine blue, permanent brown FG, brilliant first scarlet, pigment clean B, rhodamine-B base,
Solvent Red)' a 9, Solvent Red 14
6, Solvent Blue 35, etc., and mixtures thereof, etc., and usually 1 to 100 parts by weight of heat supply resin.
About 15 parts by weight are used.

Examples of the magnetic material used in the present invention include alloys or compounds containing ferromagnetic elements such as ferrite and magnetite, and the magnetic material is bound in the form of fine powder with an average particle size of 0.1 to 1 μm. It can be used by dispersing it in a resin in an amount of 40 to 70% by weight.

[Examples and effects]

Examples of the present invention will be described below, but the present invention is not limited to these examples.

All composition ratios shown in the examples are parts by weight.

Example 1 200 parts of toluene and 27 parts of isooctenylsuccinic acid are charged into a reactor equipped with a stirring device, a nitrogen inlet tube, a thermometer, a reflux condenser, and a dropping funnel, and the temperature is adjusted to 90°C. A mixed solution of styrene 9001'lS, 50 parts of 2-ethylhexyl acrylate, 23 parts of 2-hydroxyethyl acrylate, and 15 parts of benzoyl peroxide is dropwise polymerized over 5 hours under a nitrogen stream. After the dropwise addition was completed, the temperature was raised to 100'C and after aging for 4 hours, the pressure was reduced to 60 lffmHg while gradually raising the temperature to 200'C to distill off the toluene, and the molten resin was taken out into a stainless steel vat and allowed to stand. The resin was cooled and pulverized to obtain a powdered resin (softening point: 124.4°C, 'I'g: 61.3°C using Koka flow tester). This softening point was determined by using a Koka-type flow tester (manufactured by Takasugi Seisakusho) to heat a 1-part 5 sample at a heating rate of 6°C/min and applying a load of 20rf/cIL2 with a plunger. ,
When extruding a nozzle with diameter 1) II and length 11M, draw a plunger drop-temperature curve (softening flow curve) of the flow tester, and let h be the height of the B-shaped curve. The temperature corresponding to h/2 is defined as the softening point. 93 parts of the resin and 7 parts of carbon black (Su-Gal 400 R manufactured by Cabot Corporation) were mixed in a ball mill, kneaded using a hot roll, cooled, coarsely ground in a hammer mill, further finely ground in a jet mill, and then averaged after classification. A toner with a particle size of 14.2 microns was obtained. The obtained toner was mixed with carrier iron powder, and the amount of charge was measured using a blow-off measuring device, and it was found to be -17 μc/t.

The toner 91t was mixed with carrier iron powder 1209F to prepare a developer, and then used in a commercially available electrophotographic copying machine (the photoreceptor was Be, the rotation speed of the fixing roller was 255 k/sec, and the temperature of the heat roller in the fixing device was variable). When the image was produced using the same machine (with the oil applicator removed), a clear image was obtained with no background smudges, smearing, or removal of solid black areas.

The fixing temperature was controlled at 140 DEG C. to 220 DEG C., and the image fixability and offset property were evaluated. At 155 DEG C., the image was sufficiently fixed and no offset occurred. After printing up to 20,000 images, clear images were obtained with no background fogging or missing black areas.

Here, set the minimum fixing temperature, use a sand eraser with a bottom surface of 15 x 7.5 sheets, put a load of 5002 on the rubber, and rub it back and forth 5 times over the fixed image through the fixing machine. The temperature of the fixing roller when the degree of optical reflection is measured using a reflection densitometer and the fixing rate exceeds 70% according to the following definition. 40 parts of n-dodecenylsuccinic acid manufactured by Co., Ltd. was added, and the temperature was adjusted to 90°C. A mixture of 880 parts of α-methylstyrene, 50 parts of n-butyl acrylate, 30 parts of 2-hydroxyethyl methacrylate, and 15 parts of lauroyl peroxide was dropwise polymerized under a nitrogen stream over 5 hours. After raising the temperature to 200°C and aging for 4 hours.

While gradually increasing the temperature, the pressure was reduced to 60 Hg and toluene was distilled off. The molten resin was taken out into a stainless steel vat, allowed to cool, and ground to form a powdered resin (Koka flow tester, softening point: 128.5°C, Tg: 65. 2°C).

93 parts of the resin and 7 parts of carbon black (SU-GAL 400 R manufactured by Cabot Corporation) were mixed in a ball mill, mixed, crushed and classified to obtain a toner having an average particle size of 14.4 microns. The amount of charge of the obtained toner was -20 μc/f.

A developer was prepared by mixing the toner 91F with carrier iron powder 1209r, and an image was produced using the same evaluation machine as in Example 1. A clear image was obtained without background smudges, bleeding, or missing black areas. . When the fixing temperature of the fixing device was controlled and the image fixing performance and off-kit performance were evaluated, the result was 160.
It was fixed at ℃ and no offset occurred. When images were printed up to 20,000 sheets, clear images were obtained with no visible background or black solid areas.

Example 3 200 parts of toluene and 15 parts of indodecenylsuccinic acid were charged into the reactor of Example 1, and the temperature was adjusted to 90°C. 820 parts of styrene, 2 parts of acrylic acid under nitrogen flow
-90 parts of ethylhexyl, sa part of 2-hydroxyethyl methacrylate, 40 parts of diethylaminoethyl methacrylate
Part and α.

Add 5 parts of a mixture of 15 parts of α'-7di-7zobisisoptrile to
Polymerize dropwise over time. After dropping, the temperature was raised to 100°C, and after aging for 4 hours, the temperature was gradually raised to 200°C for 60 minutes.
The pressure was reduced with Hgt to distill off the toluene, the molten resin was taken out into a stainless steel vat, allowed to cool, and ground to form a powdered resin (Koka flow tester softening point: 127.6°C, 'r
g 66.5°C) was obtained.

93 parts of the resin and 7 parts of carbon black (SU-GAL 400 R, manufactured by Cabot Corporation) were mixed in a ball mill, mixed, crushed, and classified into 1 class to obtain a toner having an average particle size of 14.3 microns. The amount of charge of the obtained toner was +20 μc/f.

The toner 91F was mixed with carrier iron powder 1209F to prepare a developer, and a commercially available electrophotographic copying machine (the photoreceptor was an organic photoconductor, the rotation speed of the roller was zssm/sec, and the temperature of the heat roller in the fixing device) By controlling the fixing temperature of the fixing device and removing the oil coating device, a clear image was obtained with no background smudges or black spots. Evaluation of fixing and offset properties.

It was fixed at 160° C. and no offset occurred.

When images were printed up to 20,000 sheets, clear images were obtained with no background or black areas missing.

Comparative Example 1 Using the reactor of Example 1, a mixture of 9oo1[L 2-ethylhexyl acrylate aOS of styrene, 20 parts of 2-hydroxyethyl acrylate, and 15 parts of benzoyl peroxide] was prepared in 200 parts of toluene at 90°C. was added dropwise over 3 hours, the temperature was raised to 100°C, and the mixture was aged for 4 hours. Then Example 1
Toluene is distilled off using the method described above, extracted and pulverized to form a powdered resin (
Koka type flow tester Softening point 128.8℃, Tg 67
．． 4°C). Using this resin, a toner (charge amount Fi-19 μc/f) was prepared in exactly the same manner as in Example 1.
When a developing agent was prepared and an image was produced using the same evaluation machine as in Example 1, a clear image was obtained without background smudges, blurring, or missing black areas. When the fixing temperature of the fixing device was controlled and the image fixing and offset properties were evaluated, it was fixed at 180°C, but the percentage was 140°C to 220°C.
Offsets occurred at all temperatures up to °C.

Comparative Example 2 Using the reactor of Example 1, 890 parts of styrene, 100 g of n-butyl acrylate, in 200 parts of toluene at 90°C.
A mixed solution of 10 parts of divinylbenzene and 15 parts of lauroyl peroxide was added dropwise over 3 hours, and after aging at 100°C for 4 hours,
Toluene was distilled off by the method of Example 1, extracted and pulverized.
1 g (61.5°C) was obtained. A toner (charge amount was -18 μC/f) was prepared using the resin in exactly the same manner as in Example 1, and a developer was prepared, and an image was formed using the same evaluation machine as in Example 1. In some places, 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 property were evaluated, offset did not occur up to 220°C, but the fixing temperature was 190°C.

As can be seen from the above Examples and Comparative Examples, clear images can be obtained with the developer composition according to the present invention.

It is clear that it has excellent durability, good off-resistance, and can be fixed at low temperatures.

Applicant's agent Kaoru Furutani

Claims (1)

[Scope of Claims] 1 (a) styrene and/or a styrene derivative and (b) at least one type of (meth)acrylic acid or ester thereof, (c) one or more carboxyl groups and one A compound having 7 to 30 carbon atoms and having an unsaturated bond of 0.05% based on the total amount of (a) and (b) above.
A binding resin characterized by comprising a copolymerized resin with addition of ~10% by weight. 2. The binding resin according to claim 1, wherein the component (c) is alkenylsuccinic acid or an acid anhydride thereof. 3. In an electrophotographic dry developer composition containing a binding resin and a colorant as main components, the main components of the binding resin are (a) styrene and/or styrene derivatives, and (b) at least one type of styrene derivative. A copolymer of (meth)acrylic acid or its ester, and (c) a compound having one or more carboxyl X- and one or more unsaturated bond in the molecule and having 7 to 30 carbon atoms, A dry developer composition for electrophotography, characterized in that the content of the component (c) in the polymer is 0.05 to 10% by weight. 4. Softening point of binder resin is 100
The dry developer composition for electrophotography according to claim 3, which has a temperature of 160°C. 5. The dry developer composition for electrophotography according to claim 3, wherein the component (c) is alkenylsuccinic acid or an acid anhydride thereof.