JPS61105561A - Electrophotographic developing composition - Google Patents

Abstract

PURPOSE:To prevent an offset and to ensure a fixing at a low temp. by incorporating a polyester resin obtd. by polycondensating a specific diol, a polycarboxylic acid or its anhydride or its lower alkylester, and a polyhydric alcohol having >=3 hydroxyl groups as a main component of a binding resin to the titled composition. CONSTITUTION:In the titled composition consisting of the binding resin and the coloring agent, the polyester resin is obtd. by polycondensating the diol component shown by formula I, the polycarboxylic acid or its anhydride or its lower alkylester, and the polyhydric alcohol having >=3 hydroxyl groups shown by formula II as the main component of the binding resin. In the predescribed formula, R is an ethylene or a propylene, (x) and (y) are each >=1, and an average of (x+y) is 2-7, R1 is a hydrogen atom or 1-20C hydrocarbon group, R2 and R3 are a methylene, an oxyethylene or an oxypropylene group, (p) is 0 or 1, (m1) and (m2) may be same or different, and are 0-7, (n1) is 1-, (n2) is 0-4, (q) is 1-6, (n1)Xq>=3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developer composition for developing electrostatic images in photographic photography, electrostatic recording, electrostatic printing, and the like.

[Conventional technology and problems]

As a conventional electrophotographic method, as described in U.S. Patent Nos. 2,297,691 and 2,357,809, etc.
Uniformly charge the photoconductive insulating layer.

The layer is then exposed to light, the charge on the exposed areas dissipates to form an electrical latent image, and a colored electrically charged fine powder called toner is deposited on the latent image. visualized by (development process),
After transferring the obtained visible image to a transfer material such as transfer paper (
(transfer step), and permanent fixation (fixing step) by heating, pressure or other suitable fixing methods.

In this way, toner is used not only in the development process but also in the transfer process.
It must have the functions required in steps 6 and 11 of 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 during copying of tens to tens of thousands of sheets. To prevent this type of toner deterioration, it is best to use a strong resin with a large molecular weight that can withstand mechanical (frictional) forces, but these resins generally have a high softening point and are used in open fixing, which is a non-contact fixing method.

Radiant fixing using infrared rays has poor thermal efficiency, so the fixing is not sufficient, and contact fixing has good thermal efficiency, so even in the widely used heat roller fixed fixing method, a heat roller is used to ensure sufficient fixing. It is necessary to raise the temperature of the toner, which causes problems such as deterioration of the fixing device, curling of paper, and increased energy consumption.Using such resin improves manufacturing efficiency when making toner by pulverizing it. decreases significantly. Therefore, it is not possible to use a binder resin that has a high degree of polymerization and also has a high softening point.

On the other hand, in the heat roller fixed fixing method, the heating roller surface and the toner image surface of the fixing sheet come into pressure contact, so the thermal efficiency is extremely high, and it is widely used from low speeds to high speeds.
When the heating roller surface and the toner image surface come into contact, a so-called offset phenomenon tends to occur, in which the toner adheres to the heating roller surface and is transferred to a connecting 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 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 etc.
(The fixing device is large), which is not desirable because it is not a cost-effective instrument and is complicated, which can easily cause trouble.

There is also a method of improving the offset phenomenon by widening the molecular weight distribution width of the binder resin, as described in Japanese Patent Publication No. 55-68j5 and Japanese Patent Application Laid-Open No. 56-98202, but the degree of polymerization of the resin is high. It is also necessary to increase the fusing temperature.

A further improved method is a method of improving the offset phenomenon by making the resin asymmetrical and crosslinking, as described in Japanese Patent Publication No. 57-493, Japanese Patent Application Laid-open No. 50-44856, and Japanese Patent Application Publication No. 57-37355. 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 hot offset temperature as much as possible, the fixing temperature used can be lowered and the usable temperature range can be expanded, resulting in energy saving, high speed fixing, and prevention of curling of paper. In addition, since double-sided copying can be performed without trouble, there are many advantages such as making the copying machine more intelligent, controlling the temperature of the fixing device more accurately, and relaxing the tolerance range.

For this reason, there is a constant need for toner resins and toners that have good fixing properties and anti-offset properties.

In addition, when using a methylene-based binder resin to achieve such requirements, Japanese Patent Application Laid-Open Nos. 49-65252 and 1972
As described in No. 0-28840 and JP-A No. 50-81342, methods of adding paraffin wax, low molecular weight polyolefin, etc. as anti-offset agents are known; It has been confirmed that the developer deteriorates quickly, and in the case of polyester resin, even if the above-mentioned anti-offset agent is applied, it has little effect, and that the more the amount used, the faster the developer deteriorates.

Polyester resin inherently has good fixing properties and can be fixed sufficiently even in a non-contact fixing method as described in U.S. Pat. It was difficult to use. JP-A-50-44856, JP-A-57-37355,
As described in JP-A-5'7-109875, polyester resins with improved anti-offset properties using polycarboxylic acids do not have sufficient anti-offset properties to be used, or do not have sufficient anti-offset properties to be used. The ones that do exist are not sacrificing the low-temperature fixing properties that polyester resin originally has.
In the toner production process, the crushability was extremely poor, and there were also problems in developer production.

[Means for solving problems]

The present invention has been 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 fixed fixing method and that can be fixed at a lower fixing temperature. The goal is to provide the following.

- 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 fixed fixing method and which can be fixed at a much 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 provide a developer that exhibits good crosstalk and pulverization properties during developer production.

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 an electrophotographic developer composition comprising a binder resin and a colorant, in which the main component of the binder resin is represented by the following formula (wherein R is ethylene or propylene group, 6D,
+ 7 must each be an integer greater than or equal to 1, and! The average value of +7 is 2-7. ) and a diol component represented by.

An electrophotographic developer composition that is a polyester resin obtained by cocondensation polymerization of a polyhydric carboxylic acid, its acid anhydride, or its lower alkyl ester and a trivalent or higher polyhydric alcohol represented by the following general formula (I[). It provides:

(In the formula, R1 is hydrogen or a hydrocarbon group having 1 to 20 carbon atoms.

R2, R, is a methylene group, oxyethylene group, or oxypropylene group; p is an integer of O or 1;

J p m2 are the same or different integers from 0 to 7, nl is an integer from 1 to 4, n2 is an integer from a to 4.

q is an integer from 1 to 6.

As the diol component represented by formula (1) in the present invention (ns
Polyoxypropylene (2,2)-2,2-bis(4-
hydroxyphenyl)propane, polyoxypropylene (s,s)-2°2-bis(4-hydroxyphenyl)propane.

Polyoxyethylene (2,0) -2,2-bis(4-
hydroxyphenyl)propane, polyoxypropylene (2,0)-polyoxyethylene (2,0) -2,2
-bis(4-hydroxyphenyl)propane, polyoxypropylene(6)-2,2-bis(4-hydroxyphenyl)propane, and the like.

In addition, examples of the polyvalent carboxylic acid in the present invention include at least one selected from terephthalic acid, isophthalic acid, 7-malic acid, maleic acid, succinic acid, alkyl ° or alkenyl succinic acid having 4 to 18 carbon atoms. Among them, the alkyl or alkenyl succinic acids include, for example,
n-dodecenylsuccinic acid, indodecenylsuccinic acid, n
-Dodecylsuccinic acid, isododecylsuccinic acid, n-octylsuccinic acid, n-octenylsuccinic acid, n-butylζ
In addition to the above compounds, 1.2.
More preferably, the acid component contains 0 to 30 mol% of 4-benzenetricarboxylic acid, its acid anhydride, or its alkyl ester.

In addition, the trivalent or higher polyhydric alcohol represented by the general formula (1) in the present invention includes 1, for example, polyoxyethylene (5) -1,3,5-benzenetriol, polyoxyethylene (5) -1, 2,4-benzenetriol, polyoxypropylene (3) -1゜5.5-benzenetriol, polyoxyethylene (3) -α, α′
, α“-tris(4-hydroxyphenyl) -1,3
, 5-triisoglobilbenzene, is, s'-(1-
methylethylidene)bis(2-hydroxy-1
, 3-benzenedimethanol, 5,5'-methylenebis(2-hydroxy-1,5-benzenedimetatool), and the like. The blending ratio of the polyhydric alcohol represented by this general formula (Shu) is preferably 1 to 50 mol% in the alcohol component.

When producing the polyester resin according to the present invention,
The above raw materials are used.

It is possible to use other alcohol components and carboxylic acid components as the resin for the developer as long as the attributes of the polyester resin according to the present invention disclosed by the present invention are not lost, and such polyester resins can also be used in the present invention. include.

Further, the softening point (ring and ball softening point according to a8TM 128-sl T) of the polyester resin used in the developer composition of the present invention is preferably 100 to 180°C; if it is too low, the offset resistance may be insufficient. If it is too high, the fixing properties will be insufficient. Further, the glass transition temperature is preferably 55°C or higher.

The polyester resin used in the present invention is prepared by mixing a polyhydric carboxylic acid component and a polyol component in an inert gas Wfl atmosphere at 18%
It can be produced by polycondensation at a temperature of 0 to 250'C. In this case, in order to accelerate the reaction, commonly used esterification catalysts such as zinc oxide, stannous oxide, diptyltin oxide, diptyltin silaclate, etc. can be used. It can also be produced under reduced pressure for the same purpose.

As the colorant used in the present invention, generally known colorants can be used, such as carbon black, acetylene black, phthalocyanine blue, permanent plump FG, brilliant 7 earth scarlet, pigment green 9, rotamine Examples include B-Pace, Solvent Red 49, Solvent Red 146, Solvent Blue 35, and mixtures thereof.
Usually, about 1 to 15 parts by weight is used per 100 parts by weight of the binder resin.

The electrophotographic developer according to the present invention may be used together with other components. A typical example is a magnetic material, and examples of the magnetic material used include alloys or compounds containing elements exhibiting ferromagnetism, such as ferrite and magnetite, and the magnetic material has an average particle size of 0.1 to It can be used in the form of a 1 micron fine powder dispersed in a binder resin in an amount of 40 to 70% by weight.

〔Example〕

Examples of manufacturing the resin used in the present invention and examples of the present invention will be described below, but the present invention is not limited to these examples.

Production example 1 Polyoxypropylene (2,2) -2,2-bis(4
-hydroxyphenyl)propane 748t1 terephthalic acid 2491, fumar@174F and polyoxyethylene (3) -1,3,5-benzenetriol 1551
was placed in a four-piece 2J glass flask, fitted with a thermometer, a stainless steel stirring bar, a flowing-down condenser, and a nitrogen inlet tube, and heated to 220°C under a nitrogen stream in an electric heating mantle.
The reaction was carried out while stirring. The degree of polymerization is ASTM I!
The softening point was tracked according to f2B-51T, and the reaction was terminated when the softening point reached 122°C. The obtained resin was a pale yellow solid, and the glass transition temperature measured by D8C (differential calorimeter) was 66°C.0 The obtained resin was referred to as resin (1).0 Production Example 2 Polyoxypropylene (2) ,2) -2,2-bis(4
-Hydroxyphenylene/I/) Gronoku 75541% polyoxyethylene (2) -2,2-bis(4-hydroxyphenyl)propane 4751% Terephthalic acid 549
1. and polyoxyethylene (5) -1゜5.5-be/Centriol 59f were reacted at 220°C using exactly the same equipment as in Production Example 1 to obtain 1,2,4-benzenetricarboxylic acid 189f The reaction was terminated when the softening point reached 122°C. The obtained resin was a pale yellow solid with a glass transition point of 64°C. Production Example 3 Polyoxypropylene (2,2) -2,2-bis(4) using this resin as resin (2)
-Hydroxyphenyl)gulon(n)748 f.

Inphthalic acid 5991. Indodecenyl Anhydrous Kohari lol!
159t was reacted at 220°C using exactly the same equipment as in Production Example 1. Furthermore, s,s'-(1-methylethylidene)bis(2-hydroxy-1,3-benzenedimetatool) 157t was added. The reaction continues until the softening point reaches 1.
The reaction was terminated when the temperature reached 20°C. The resulting resin was a yellow solid with a glass transition temperature of 65°C. Production Example 4 Polyoxypropylene (2,2) -2,2-bis(4) using this resin as resin (5)
-Hydroxyphenyl)propane 5541° Polyoxyethylene (2) -2,2-bis(4-hydroxyphenyl)propane a75t, TeV7tal1. i#46
1 and polyoxyethylene (3)-α.

α′, α“-tris(4-hydroxyphenyl)-1,
3,5-) Liisopropylbenzene 92f was reacted at 220° C. using the same apparatus as in Preparation Example 1.

Further, 1,2,4-benzenetricarboxylic acid F11651 was added to continue the reaction, and the reaction was terminated when the softening point reached 124°C.

The obtained resin is referred to as resin (4).

Production Example 5 In Production Example 1, polyoxyethylene (3) -1°3.
Polyoxypropylene (2,2) -2,2 was used to keep the alcohol/acid ratio constant except for 5-benzenetriol.
-bis(4-hydroxyphenyl)propane at 320r
Polymerization was carried out in exactly the same manner except for the increase in temperature, and the reaction was terminated when the softening point reached 122°C.

The obtained resin is referred to as Comparative Resin (1).

Production Example 6 In Production Example 1, polyoxyethylene (3)-1,3゜5
- Polymerization was carried out in exactly the same manner except that an equivalent amount of glycerin was used in place of benzenetriol, and the softening point was 12.
The reaction was terminated when the temperature reached 2° C. The resulting resin is referred to as Comparative Resin (2).

Production Example 7 In Production Example 2, polyoxyethylene (3) -1°3.
In order to keep the alcohol/acid ratio constant, 5-benzenetriol was polymerized in exactly the same manner except that the amount of TEL7 was reduced by 589, and the reaction was terminated when the softening point reached 122°C.

The obtained resin is referred to as Comparative Resin (3).

Production Example 8 In Production Example 3, s,s'-(1-methylethylidene)bis(2-hydroxy-1,3-benzenedimetatool)
Polymerization was carried out in exactly the same manner except that an equal amount of pentaerythritol was used instead.

The obtained resin is referred to as comparative resin (4).

Example 1 10 parts by weight of the resin (1) obtained in Production Example 1 and 10 parts by weight of carbon black (Mitsubishi Kasei MA600) were mixed uniformly in a ball mill, melted in a pressure kneader, mixed, and then mixed in a jet mill. The powder was pulverized to produce a toner having an average particle size of 12 μm.

100 tons of the obtained toner was mixed with iron powder (DBP1 manufactured by Dowa Iron Powder Co., Ltd.).
35) A developer was prepared by mixing with 1.2.

When the developer was used to produce an image using a commercially available copying machine, a clear image without background smudge was obtained.

In addition, no offset was observed when the fixing temperature of the heat roller was changed by using an external fixing device (only the fixing unit of a commercially available copying machine was made independent).

Further, the toner 30F was placed in a 50 cc polyglopylene cleft temple bottle and left to stand at 55°C for one week, and the blocking properties of the toner were examined, and the toner showed exactly the same fluidity as before storage and no solidification was observed.

Examples 2 to 4 and Comparative Examples 1 to 4 Developers were prepared using the same formulation and exactly the same procedure as in Example 1 for resins (2) to (4) and comparative resins (1) to (4). Furthermore, evaluation was performed using exactly the same procedure.

The results are shown in Table 1.

It is clear from the above results that one of the fruits of the present invention (both on the downstream side has excellent storage stability and high hot offset properties, yet has a low fixing temperature and excellent image quality). It shows.

On the other hand, when a commonly known polyhydric alcohol with a valence of 3 or higher is used, unfavorable phenomena such as storage stability, image stability due to environmental changes, fixing performance/hot offset property, etc. are observed.

Claims (1)

[Scope of Claims] 1. In an electrophotographic developer composition consisting of a binder resin and a colorant, the main component of the binder resin is represented by the following formula ▲ Numerical formula, chemical formula, table, etc. ▼ (I) (in the formula R is an ethylene or propylene group, x, y
are each an integer of 1 or more, and the average value of x+y is 2 to 7. ) A polyester resin obtained by co-condensation polymerization of a diol component represented by (), a polyvalent carboxylic acid or its acid anhydride, or its lower alkyl ester, and three or more polyhydric alcohols represented by the following general formula (II). An electrophotographic developer composition characterized by certain features. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (In the formula, R_1 is hydrogen or a hydrocarbon group having 1 to 20 carbon atoms, R_2 and R_3 are methylene group, oxyethylene group, oxypropylene group, p is 0 or m_1 and m_2 are the same or different integers from 0 to 7, n_1 is an integer from 1 to 4, n_2 is an integer from 0 to 4, q is an integer from 1 to 6, and n_1×q≧3. 2. The electrophotographic developer composition according to claim 1, wherein the proportion of the polyhydric alcohol represented by formula (II) in the alcohol component is 1 to 50 mol %. 3 Polyvalent carboxylic acids include terephthalic acid, isophthalic acid,
The electrophotographic developer composition according to claim 1, which is at least one selected from fumaric acid, maleic acid, succinic acid, and alkyl or alkenyl succinic acids having 4 to 18 carbon atoms. 4 Polyester resin has a ring and ball softening point of 100-180℃
, the glass transition temperature is 55°C or higher.
The electrophotographic developer composition described in 1. 5. The electrophotographic developer composition according to claim 1, wherein the polyester resin contains 0 to 3.0 mol% of 1,2,4-benzenetricarboxylic acid, its acid anhydride, or its alkyl ester in the acid component. .