JPH04337737A - Electrostatic charge image developing toner - Google Patents

Abstract

PURPOSE:To obtain excellent offset resistance and the transparency of OHP images and to substantially prevent the generation of filming on the surface of a photosensitive body by using a binder resin, coloring agents and low mol.wt. polypropylene (PP) as essential components and compounding a nucleus agent and modified polyolefin resin therewith. CONSTITUTION:This toner consists mainly of the binder resin, the coloring agents and the low mol.wt. PP and further contains the nucleus agent and the polyolefin resin modified with unsatd. carboxylic acid, unsatd. dicarboxylic acid or the acid anhydride thereof. The PP mixture of the toner consisting mainly of the binder resin, coloring agent and low mol.wt. PP mixture may be formed by dispersing and mixing the nucleus agent and the polyolefin resin modified with the unsatd. carboxylic acid, unsatd. dicarboxylic acid or the acid anhydride thereof in and with the low mol.wt. PP.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is applicable to electrophotography, electrostatic recording,
The present invention relates to a dry toner for developing electrostatic images in electrostatic printing and the like.

0002

[Prior Art] Methods for developing electrostatic images are broadly divided into liquid developing methods that use a developer in which various pigments and dyes are finely dispersed in an insulating organic liquid, cascade methods, magnetic brush methods, There is a dry development method, such as a powder cloud method, which uses a fine powder developer called a toner in which a colorant is dispersed in a natural or synthetic resin.

In the dry development method, an electrostatic image is developed using toner, transferred onto a transfer sheet, and then fused and fixed onto the transfer sheet to obtain a copy. In this case, the toner image is fused by contact with solution vapor, by pressure, or by heating. As the heating method, a non-contact heating method using an electric furnace, a pressure heating method using a heating roller, etc. are generally adopted.

[0004] In the pressure heating method using a heating roller, the toner image surface of the sheet to be fixed is passed through the surface of the heating roller, the surface of which is made of a material that has releasability to the toner, while being in pressure contact with the toner, thereby fixing the sheet. It is something that is done;
Generally referred to as the heating roller fixing method, this method brings pressure contact between the surface of the heating roller and the toner image surface of the fixing sheet, resulting in extremely high thermal efficiency when fusing the toner image onto the fixing sheet. It is good and can be fixed quickly. However, in this method, the surface of the fixing roller and a portion of the toner image may adhere to the surface of the fixing roller, resulting in a so-called offset phenomenon, which may cause stains on the sheet to be fixed.

Therefore, in order to prevent offset, there are methods of supplying a liquid with release properties such as silicone oil to the surface of the fixing roller and coating the roller surface with a thin film of the liquid, and a method in which the toner contains a resin with release properties. Method of making
04 Publication) and a method of combining these methods.

[0006]

However, the method of applying a releasable liquid to the surface of the fixing roller requires a liquid applicator to be installed in the fixing device, which increases costs.
Furthermore, there are drawbacks such as an odor caused by the releasing liquid during fixing. In addition, the method of adding a resin with release properties to the toner may reduce the transparency of the toner, reduce the quality of OHP images in the case of color toners, or even cause release of the resin with release properties. However, there were problems such as abnormal images being produced due to filming on the surface of the photoreceptor.

Therefore, it is an object of the present invention to solve these problems, namely, to solve the problem of toner being fused to the surface of the fixing roller.
It is an object of the present invention to provide a toner that can be efficiently fixed with a hot roller without causing the so-called offset phenomenon, has good transparency of an OHP image, and does not cause filming on the surface of a photoreceptor.

[0008]

[Means for Solving the Problem] As a result of extensive studies, the present inventors have discovered that a toner containing a nucleating agent and a modified polyolefin resin together with low molecular weight polypropylene is suitable for the above purpose. The invention was completed.

That is, according to the present invention, there is provided a toner mainly consisting of a binder resin, a colorant, and a low molecular weight polypropylene, which is further modified with a nucleating agent and an unsaturated carboxylic acid, an unsaturated dicarboxylic acid, or an acid anhydride thereof. There is also provided a toner for developing electrostatic images, characterized in that it contains a binder resin, a colorant, and a low molecular weight polypropylene mixture, the polypropylene mixture being a low molecular weight polypropylene mixture. There is provided a toner for developing electrostatic images, characterized in that it is made by dispersing and mixing a nucleating agent and a polyolefin resin modified with an unsaturated carboxylic acid, an unsaturated dicarboxylic acid, or an acid anhydride thereof in molecular weight polypropylene. Ru.

The toner of the present invention is a mixture of a binder resin, a colorant, and a low molecular weight polypropylene, and a nucleating agent and a modified polyolefin resin. However, crystalline polymers such as polypropylene are usually Transparency is poor due to uneven formation. However, when a nucleating agent is added to polypropylene, the nucleating agent disperses in the polypropylene and becomes the nucleus of the crystal. As a result, the polypropylene crystals become fine and uniform. Furthermore, when a modified polyolefin resin is added,
The compatibility of polypropylene with the binder resin is increased and the polypropylene is homogeneously dispersed in the toner, resulting in a significant increase in transparency.

Furthermore, when polypropylene is added to the toner, continuous use of a copying machine causes the polypropylene to film on the surface of the photoreceptor, resulting in a decrease in image quality. When the filmed polypropylene was analyzed, it was confirmed that it was amorphous polypropylene. However, when a nucleating agent and a modified polyolefin resin are added to polypropylene, crystallization and compatibility of the polypropylene are increased, and filming of the polypropylene on the photoreceptor surface is reduced.

Therefore, the toner of the present invention not only exhibits excellent anti-offset properties during heating roller fixation, but also provides good transparency of OHP images, and is less likely to cause filming on the surface of the photoreceptor.

Nucleating agents used in the present invention include alum, silica, titanium, calcium oxide, magnesium oxide, ε-caprolactam, talc, polyester fiber, nylon fiber, i-PS, brominated biphenyl ether, Dechloraue B, and dichloromethane. Benzylidene sorbitol (DBS), p-methyl-DBS, dimethyl-DB
Substituted DBS such as S, p-ethyl DBS, i-propyl DBS, p-chloro DBS, bis(p-ethylbenzylidene) sorbitol, organic carboxylate, organic phosphate,
Examples include cyclic triethylene glycol terephthalate.

[0014] Furthermore, the modified polyolefin resin used in the present invention can be produced by a known method. For example, it can be produced by a method in which the following polyolefin resin and the following unsaturated carboxylic acid are reacted under heating in a solution state or a molten state. In this case, the polyolefin resin is a homopolymer or copolymer of ethylene, propylene, butylene, etc., and the comonomer is a halogenated polyolefin modified with vinyl acetate, vinyl chloride, (meth)acrylic acid ester, chlorine, etc. can be used.

Examples of unsaturated carboxylic acids or unsaturated dicarboxylic acids or their acid anhydrides used for modification include acrylic acid, methacrylic acid, maleic acid monoalkyl ester, fumaric acid monoalkyl ester, crotonic acid, maleic acid, and fumaric acid. Examples include acids, itaconic acid, maleic anhydride, itaconic anhydride, and the like. In addition, commercially available products include, for example, MPX-1000, MPX-1010, M
Examples include PX-1001 and MPX-2000 (both manufactured by Sanyo Chemical Industries, Ltd.).

[0016] The amount of the nucleating agent added is 10
0.005 to 5 parts by weight per 0 parts by weight is desirable. In addition, the amount of modified polyolefin resin added is as follows: toner 1
0.1 to 10 parts by weight per 00 parts by weight is desirable.

The toner of the present invention is made by blending a binder resin, a colorant, and a low molecular weight polypropylene with the above-mentioned nucleating agent and a modified polyolefin resin, and the manufacturing method thereof is arbitrary, but it can be produced by any conventional method. In the method, all the above ingredients are first mixed. However, as mentioned above, the nucleating agent and modified polyolefin resin are blended to modify the low molecular weight polypropylene (mold release agent) component in the toner, so the nucleating agent and modified polyolefin resin are added to the low molecular weight polypropylene in advance. It is very preferable from the viewpoint of the performance of the toner and the production of the toner to prepare a mixture obtained by dispersing and mixing the modified polyolefin resin and to use the mixture as a release agent component to make a toner. .

As described above, when the nucleating agent and the modified polyolefin resin are dispersed and mixed in low molecular weight polypropylene in advance, the amount of the nucleating agent added is preferably 0.05 to 10 parts by weight per 100 parts by weight of polypropylene. The amount of modified polyolefin resin added is preferably 0.1 to 5 parts by weight per 1 part by weight of polypropylene.

As the binder resin used in the toner of the present invention, all binder resins conventionally used as binder resins for toners can be used. Specifically, polystyrene,
Monopolymers of styrene and its substituted products such as polychlorostyrene and polyvinyltoluene; styrene/p-chlorostyrene copolymers, styrene/propylene copolymers, styrene/vinyltoluene copolymers, styrene/vinylnaphthalene copolymers , styrene/methyl acrylate copolymer, styrene/ethyl acrylate copolymer, styrene/butyl acrylate copolymer, styrene/octyl acrylate copolymer, styrene/methyl methacrylate copolymer,
Styrene/ethyl methacrylate copolymer, styrene/butyl methacrylate copolymer, styrene/α-methyl chloromethacrylate copolymer, styrene/acrylonitrile copolymer, styrene/vinyl methyl ether copolymer,
Styrene/vinyl ethyl ether copolymer, styrene/
Styrenic compounds such as vinyl methyl ketone copolymer, styrene/butadiene copolymer, styrene/isoprene copolymer, styrene/acrylonitrile/indene copolymer, styrene/maleic acid copolymer, and styrene/maleic acid ester copolymer Copolymers: polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenolic resin, aliphatic or fatty resin Cyclic hydrocarbon resin, aromatic petroleum resin,
Examples include chlorinated paraffin and paraffin wax, which may be used alone or in combination of two or more.

Furthermore, as the colorant used in the toner of the present invention, all known colorants for toners can be used. As the black coloring agent, for example, carbon black, aniline black, furnace black, lamp black, etc. can be used. Examples of cyan colorants that can be used include phthalocyanine blue, methyllene blue, Victoria blue, methyl violet, aniline blue, and ultramarine blue. Examples of magenta colorants include Rhodamine 6G Lake, Dimethylquinacridone, Watching Red, Rose Bengal, and Rhodamine B.
, alizarin lake, etc. can be used. Examples of yellow colorants that can be used include chrome yellow, benzidine yellow, Hansa yellow, naphthol yellow, molybdenum orange, quinoline yellow, and tartrazine.

Furthermore, the toner of the present invention may contain, for example, dyes and pigments, charge control agents, etc. in order to provide more efficient charging. Examples of charge control agents include metal complex salts of monoazo dyes, nitrofumic acid and its salts, salicylic acid, naphthoic acid, Co, Cr, or Fe of dicarboxylic acids.
metal complexes, organic dyes, quaternary ammonium salts, etc.

[0022] In order to obtain the toner of the present invention, conventionally known toner manufacturing methods can be employed. For example, a binder resin, a colorant, a low molecular weight polypropylene, the nucleating agent, the modified polyolefin resin, and if necessary a charge control agent are melt-kneaded using hot rolls at 120°C, then cooled and solidified, and then mixed using a jet mill. Obtained by crushing and classifying. When using a low molecular weight polypropylene mixture, prepare a mixture in advance by dispersing and mixing the nucleating agent and the modified polyolefin resin in the low molecular weight polypropylene, and then add the nucleating mixture to the binder resin, colorant, etc. do it.

[0023]Additives may be mixed into the toner of the present invention, if necessary. Examples of additives include fluidizing agents such as colloidal silica, metal oxides such as titanium oxide and aluminum oxide, abrasives such as silicon carbide, and lubricants such as fatty acid metal salts. The additive may be mixed with the toner by any conventionally known method, and may be mixed using an apparatus such as a Henschel mixer or a speed kneader.

The toner of the present invention is used as a dry one-component developer and a dry two-component developer. When used as a dry two-component developer, the amount of carrier and toner of the present invention to be used is such that the toner particles adhere to the carrier surface of the carrier particles and occupy 30 to 90% of the surface area. It is preferable to do so. In this case, all conventionally known carriers can be used, such as uncoated carriers such as iron powder and ferrite, carriers coated with styrene/acrylic resin, silicone resin, fluorine-modified acrylic resin, etc., and granulated carriers. etc. are used.

[0025]

EXAMPLES The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited thereto. Note that all parts shown below are based on weight.

Example 1 Polyester resin

90 parts low molecular weight polypropylene

5 parts Maleic anhydride modified polypropylene
5 parts Bis(p-ethylbenzylidene) sorbitol 0
．． Part 03 Chrome Yellow

5 parts Salicylic acid zinc salt

2 parts The mixture having the above composition was melt-kneaded, cooled, pulverized, and classified to obtain a toner having an average particle size of 8.6 μm.

Example 2 Styrene/acrylic copolymer
9
2 parts low molecular weight polypropylene

6 parts Acrylic acid modified polyethylene

2 parts Bis(p-ethylbenzylidene) sorbitol 0.0
Part 5 Phthalocyanine blue

Part 2 Salicylic acid zinc salt

Two parts of the mixture having the above composition were melt-kneaded, cooled, pulverized, and classified to obtain a toner having an average particle size of 8.3 μm.

Example 3 Styrene/acrylic copolymer
9
2 parts low molecular weight polypropylene

4 parts Maleic anhydride modified polyethylene

4 parts Bis(p-ethylbenzylidene)
Sorbitol 0.05 parts Phthalocyanine blue

Part 2 Quaternary ammonium salt

Two parts of the mixture having the above composition were melt-kneaded, cooled, pulverized, and classified to obtain a toner having an average particle size of 8.5 μm.

Example 4 Polyester resin

90 parts low molecular weight polypropylene

5 parts Maleic anhydride modified polypropylene
5 parts p-methyl DBS

0.03 part chrome yellow
5
Part Salicylic acid zinc salt

Two parts of the mixture having the above composition were melt-kneaded, cooled, pulverized, and classified to obtain a toner having an average particle size of 8.6 μm.

Example 5 Styrene/acrylic copolymer
9
2 parts low molecular weight polypropylene

4 parts Maleic anhydride modified polyethylene

Part 4 DBS

0.05 parts Phthalocyanine blue
2nd part
Quaternary ammonium salt

Two parts of the mixture having the above composition were melt-kneaded, cooled, pulverized, and classified to obtain a toner having an average particle size of 8.5 μm.

Example 6 (Mold release agent mixture 1) Low molecular weight polypropylene

80 parts Maleic anhydride modified polyethylene

20 parts Bis(p-ethylbenzylidene) sorbitol 0.3 parts The mixture having the above composition was melt-kneaded, cooled, and coarsely ground to prepare a mold release agent mixture 1.

Polyester resin

90 parts mold release agent mixture 1

Part 10 Chrome Yellow

5th part
Salicylic acid zinc salt

Two parts of the mixture having the above composition were melt-kneaded, cooled, pulverized, and classified to obtain a toner having an average particle size of 8.6 μm.

Example 7 Styrene/acrylic copolymer
9
2 parts mold release agent mixture 1

Part 8 Phthalocyanine blue

Part 2 Salicylic acid zinc salt
Two parts of the mixture having the above composition were melt-kneaded, cooled, pulverized, and classified to obtain a toner having an average particle size of 8.3 μm.

Example 8 (Mold release agent mixture 2) Low molecular weight polypropylene

50 parts acrylic acid modified polyethylene

50 parts bis(p-ethylbenzylidene) sorbitol 3
A mixture having the above composition was melt-kneaded, cooled, and coarsely pulverized to prepare a mold release agent mixture 2.

Styrene/acrylic copolymer
9
2 parts mold release agent mixture 2

Part 8 Phthalocyanine blue

Part 2 Quaternary ammonium salt
Two parts of the mixture having the above composition were melt-kneaded, cooled, pulverized, and classified to obtain a toner having an average particle size of 8.5 μm.

Example 9 (Mold release agent mixture 3) Low molecular weight polypropylene

80 parts Maleic anhydride modified polypropylene

20 parts DBS

0.3 part A mixture having the above composition was melt-kneaded, cooled, and coarsely ground to prepare a mold release agent mixture 3.

Polyester resin

90 parts mold release agent mixture 3

Part 10 Chrome Yellow

5th part
Salicylic acid zinc salt

Two parts of the mixture having the above composition were melt-kneaded, cooled, pulverized, and classified to obtain a toner having an average particle size of 8.6 μm.

Example 10 Styrene/acrylic copolymer
9
2 parts mold release agent mixture 3

Part 8 Phthalocyanine blue

Part 2 Salicylic acid zinc salt
Two parts of the mixture having the above composition were melt-kneaded, cooled, pulverized, and classified to obtain a toner having an average particle size of 8.3 μm.

Example 11 (Release agent mixture 4) Polypropylene

50 parts Maleic anhydride modified polyethylene
50 parts bis(p-ethylbenzylidene)
Sorbitol
3 parts of the mixture having the above composition, melt-kneaded, cooled and coarsely pulverized,
A mold release agent mixture 4 was prepared.

Styrene/acrylic copolymer
9
2 parts mold release agent mixture 4

Part 8 Phthalocyanine blue

Part 2 Quaternary ammonium salt
Two parts of the mixture having the above composition were melt-kneaded, cooled, pulverized, and classified to obtain a toner having an average particle size of 8.5 μm.

Comparative Example 1 Polyester resin

90 parts low molecular weight polypropylene

Part 10 Chrome Yellow

5 parts Salicylic acid zinc salt

Two parts of the mixture having the above composition were melt-kneaded, cooled, pulverized, and classified to obtain a toner having an average particle size of 8.8 μm.

Comparative Example 2 Styrene/acrylic copolymer
9
2 parts low molecular weight polypropylene

Part 8 Phthalocyanine blue

Part 2 Salicylic acid zinc salt

Two parts of the mixture having the above composition were melt-kneaded, cooled, pulverized, and classified to obtain an average particle size of 8.
．． A toner of 4 μm was obtained.

The toner obtained above was evaluated in the following manner. That is, 5 parts of toner and 95 parts of non-coated amorphous iron powder carrier were continuously stirred in a ball mill pot to form a developer, and IMAGI manufactured by Ricoh Co., Ltd.
The film was set in a modified O-320 digital copying machine, and filming on the surface of the photoreceptor was evaluated. The results are shown in Table 1.

[0044]

[Table 1]

From Table 1, it can be seen that the toner of the present invention has a hot offset margin and does not cause toner filming on the surface of the photoreceptor.

[0046]

Effects of the Invention The toner of claim 1 has a structure in which the main components are a binder resin, a colorant, and a low molecular weight polypropylene, and further contains a nucleating agent and a modified polyolefin resin, so that it has the following advantages. It has the same effect. (a) Shows excellent offset resistance in heating roller fixing. (b) The transparency of the OHP image is good. (c) Filming is less likely to occur on the surface of the photoreceptor.

Further, the toner of claim 2 has a structure in which the main components are a binder resin and a colorant, and further a mixture prepared by dispersing and mixing a nucleating agent and a modified polyolefin resin in low molecular weight polypropylene is blended in advance. Therefore, it becomes easy to modify the low molecular weight polypropylene, which has the added effect of improving the above-mentioned properties and making production easier.

Claims (2)

[Claims] Claim 1: A toner mainly comprising a binder resin, a colorant, and low molecular weight polypropylene, further comprising a nucleating agent and a polyolefin resin modified with an unsaturated carboxylic acid, an unsaturated dicarboxylic acid, or an acid anhydride thereof. A toner for developing electrostatic images characterized by: 2. A toner mainly comprising a binder resin, a colorant, and a low molecular weight polypropylene mixture, wherein the polypropylene mixture comprises a low molecular weight polypropylene, a nucleating agent, and an unsaturated carboxylic acid, an unsaturated dicarboxylic acid, or an acid anhydride thereof. A toner for developing an electrostatic image, characterized in that it is made by dispersing and mixing a polyolefin resin modified with.