JPS61219963A - Positively electrifiable toner - Google Patents

Abstract

PURPOSE:To improve melt kneadability and durability by incorporating a metal or its oxide or the like in a copolymer obtained by polymerizing monomers contg. an aminoacrylic monomer in the presence of a specified polymerization initiator to form a positively electrifiable toner. CONSTITUTION:The copolymer is obtained by copolymerizing monomers contg. an aminoacrylic monomer, such as dimethylaminoethyl acrylate, in an amt. of 2-15wt%, and as other monomers, styrene or acrylic type monomers or the like in the presence of a polymerization initiator represented by the formula shown here, R1-R4 being a 1-8C satd. hydrocarbon group, and at least one of them being a >=2C group. This copolymer is added together with a metal, metal oxide, metal sulfide, metal halide, or the like to the positively electrifiable toner to regulate its saturation magnetization to <=10emu/g in an external magnetic field of 5,000Oe, and the addition of a specified aminoacrylate type copolymer into the positively electrifiable toner permits pulverizability, toner scattering resistance, and electrifiability to be improved.

Description

[Detailed Description of the Invention] [Technical Field to Which the Invention Pertains] The present invention relates to a dry toner used in electrophotography, electrostatic recording, electrostatic printing, etc., and more specifically, to a dry toner containing a magnetic material such as magnetite. The present invention relates to a substantially non-magnetic positively chargeable toner.

[Description of prior art]

Conventionally, developing methods using non-magnetic toner in electrophotography include, for example, the cascade method described in U.S. Pat. No. 2,618,552, and, for example, U.S. Pat. No. 2,221,766. Methods such as the powder cloud method described in
Generally, as a representative example, U.S. Patent No. 2.874.063
In order to efficiently convey the non-magnetic toner to the developing section as seen in the specification, there is a method of mixing the toner with magnetic particles such as iron powder or ferrite powder. A so-called two-component magnetic brush development method is widely known in which a p-electrostatic charge image is developed by mixing particles with a magnetic brush to form a magnetic brush and rubbing the magnetic brush against the surface of a photoreceptor having an electrostatic charge image. ing. In this method, the substantially non-magnetic toner must be maintained in a uniformly mixed state with the magnetic particles in the developing section, and the force to achieve this state is mainly static electricity. physical attraction and physical adhesion are dominant.

That is, it is required that the amount of electrostatic charge and triboelectric charging ability of the toner be precisely controlled. It is well known that, particularly with regard to positively chargeable toners, searches have been made to find optimal positive charge controllability and positively chargeable resins in order to precisely control the chargeability of positively chargeable toners. Nowadays, color images are desired, and since the resin itself is colorless, there is a strong desire for the emergence of an appropriate positively charging resin that can uniformly and strongly positively charge toner and can be applied to color toners. be.

However, so far, not many uniformly positively charged toner resins have been found, especially for positively chargeable toners, and even the conventionally known resins have problems and are not fully satisfactory. . For example, the positively chargeable resin shown in the examples described in Japanese Patent Publication No. 47-41931 is a mechanically brittle resin because it contains an excessive amount of an amino component that controls positive chargeability. , mechanical strength required as a binder resin for toner,
It has problems in terms of durability, stable productivity, etc. In addition, when the positively chargeable resin shown in the examples described in JP-A-54-143647 is used as a binder resin for toner, the pulverizability in the pulverization process during toner particle production is improved. However, there are problems in that it is difficult to maintain a good balance between the toner particles and the fixing performance in fixing the toner particles, and only so-called non-viscous toner can be obtained. Furthermore, in the case of the positively chargeable resin described in JP-A-58-72950, it is often too hard to be used as a binder resin for toner because it has a small amount of amino components, and it also has a stable positive charge. It also has the problem that it is difficult to obtain charging properties. In this way, conventional positively chargeable binder resins for toners have appropriate positive chargeability, but the durability and
The reality is that it is not possible to create a positively chargeable resin that satisfies all requirements such as thermal stability, fixing performance, storage stability, cleaning performance of the photoreceptor surface, and productivity. In other words, all of the resins conventionally considered to be positively chargeable have a charge control role, and are completely unsuitable for use as the main binder resin of toner. . Incidentally, especially in the case of the toner used in the above-mentioned two-component magnetic brush development method, since it is a positively charged non-magnetic toner that does not contain any magnetic material mixed with hard magnetic particles and consists essentially only of organic matter, the main binder is Therefore, there are no examples of toners in which such a suitable resin is used as the main binder resin.

Regarding conventional non-magnetic positively chargeable toner, although its chargeability, fluidity, etc. can be controlled in terms of developability, it is important to prevent unexpected situations such as toner scattering. is not sufficient, and in some cases, it may cause serious problems, especially if the toner cannot be collected by magnetic force.

[Purpose of the invention]

An object of the present invention is to provide a positively chargeable toner that solves the above-mentioned problems.

Another object of the present invention is to provide a positively chargeable toner suitable for use in combination with magnetic particles.

Still another object of the present invention is to use a copolymer having excellent compatibility and affinity with other polymers and colorants in combination with inorganic particles, which can be easily made into fine particles, and which is highly productive. An object of the present invention is to provide a positively chargeable toner rich in .

Another object of the present invention is to provide a positively chargeable toner that has excellent durability for long-term use.

Yet another object of the present invention is to provide a positively chargeable toner with excellent fixing properties.

Another object of the present invention is to provide a positively chargeable toner having excellent environmental stability and storage stability.

Still another object of the present invention is to provide a cleaning method that does not cause damage or filming to the surface of a photoreceptor.

[Structure and effect of the invention]

The positively chargeable toner of the present invention, which achieves the above-mentioned objects of the present invention, contains an aminoacrylic monomer in an amount of 2 to 15% by weight in all the constituent components, and has the structural formula as a polymerization initiator: % Formula % [However, in the formula, R1, R2, R5, and R4 are each a saturated hydrocarbon group having 1 to 8 carbon atoms, and at least one group among them is a saturated hydrocarbon group having 2 or more carbon atoms. It is something. ] A copolymer obtained using the compound represented by and containing one or more of metals, metal oxides, metal sulfides, and metal halides, and has a saturation magnetization in an external magnetic field of 5000 Oe. is 10 emu/
It is characterized by the following:

The present inventors conducted intensive research to develop an optimal positively chargeable toner by eliminating the various problems mentioned above regarding conventional positively chargeable toners, and as a result, they used a compound represented by structural formula (1). When the copolymer obtained by It has properties such as hardness, viscosity, and brittleness, and has excellent mechanical crushability, melt spray granulation properties, etc., and is easy to atomize into toner, which means it has excellent toner productivity. It goes without saying that the toner has stable positive chargeability, as well as durability for long-term continuous use, fixability, and storage stability under special environments such as high temperature and high humidity, low temperature and low humidity. Furthermore, toner scattering during the development, transfer, and fixing processes is extremely low, and furthermore, there are no problems such as damage to the surface of the photoreceptor made of organic photoconductive substances or amorphous silicon, and filming. It was found as a fact that this does not occur, and the present invention was completed based on these facts.

The aminoacrylic monomer used in the copolymer of the present invention is
Those represented by the following structural formula (n) are preferred.

CH, = C(n) [However, % R5 is a hydrogen atom, a methyl group or an ethyl group, R6 is a substituted or unsubstituted alkylene group having 1 to 4 carbon atoms, R7 and R8 are Each carbon number is 1~
Six substituted or unsubstituted alkyl groups, or a phenyl group. ] Specifically, the aminoacrylic monomer represented by the structural formula (It) includes acrylate derivatives such as dimethylaminoethyl acrylate, diethylaminoethyl acrylate, and dibutylaminoethyl acrylate%N-ethyl-N-enylaminoethyl acrylate. Also, methacrylate derivatives such as dimethylaminoethyl methacrylate, dietylaminoethyl methacrylate, dibutylaminoethyl methacrylate, and N-ethyl-N-phenylaminoethyl methacrylate can be used. Considering the influence on the hardness and viscosity of the resulting copolymer, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, diethylamine methyl acrylate, and dimethylaminoethyl methacrylate are particularly preferred.

As the constituent components of the copolymer used in the present invention other than the above-mentioned aminoacrylic monomers, all conventionally known monomers can be used, but generally vinyl monomers, particularly styrene monomers, are used. It is desirable that the acrylic comonomer is contained in an amount of 70% by weight or more. Specific examples of styrenic monomers include styrene, vinyltoluene, α-methylstyrene, etc., and specific examples of acrylic monomers include acrylic acid, methyl acrylate, Examples include esters of ethyl, propyl, butyl, or 2-ethylhexyl, methacrylic acid, esters of methyl methacrylate, ethyl, furoyl, butyl, or 2-ethylhexyl, and the like. Among these, particularly preferred ones are at least a styrene monomer and a homopolymer having a Ty (glass transition point) of approximately 30.
It is a copolymer consisting of acrylic acid or methacrylic acid ester having a temperature of 0.degree. C. or lower and the above aminoacrylic monomer.

As the polymerization initiator used in the copolymer of the present invention, all compounds represented by the structural formula (1) can be used, but in order to appropriately adjust the hardness, viscosity, brittleness, etc. of the resulting copolymer, is %R,,R2,R3, and -C
Ha, -CH2CH2, -CH2CH2(J肱CH(C
H3)2, -CH2CH,CH,CH,, -CH(CH
3) CH2CH3, -CH2CH(CH3)2, -C
(CHa)fi, -CH2CH2CH2CH2CH
a, -CLCH2CH2CH2CH2CHs, -CH2
It is desirable to appropriately select one or more types from groups such as CH (CTC), C (CTC), C (C), C (C), C (Mu), and the like. Also, s Rls R2% R3, and all of the mountains are -CH
If there are three groups, the effect of the addition of the initiator will not appear on the mechanical and thermal properties of the copolymer, making it difficult to control the physical properties well, which is not preferable.

In order to fully exhibit its function, the above-mentioned copolymer used in the present invention must be present in a proportion of 30% by weight in the toner.
As mentioned above, it is preferable to contain the amount of 50% by weight or more.

Regarding the metals, metal oxides, metal sulfides, and metal halides used in the present invention, all conventionally known metals can be used as long as they are stable at room temperature and do not have strong magnetism. For example, cr, Mnx l
;'e1co, Ni%cu%zn.

Ti%Ba%Ce, A4. V%Mo, Ags, I
n%Sn%Sb, W, Pt.

Examples include metals such as Au, (::d) and their oxides, sulfides, and halides.Also, alloys of the metals and eutectics of the metal compounds may be used. The inorganic substance is used in the form of particles, and since they are to be uniformly dispersed in the toner, it is desirable that the particle size be 5 μm or less, preferably 3 μm or less.

In addition, these inorganic particles are required to exhibit the above-mentioned effects in a proportion of 100 parts by weight of toner binder resin.
It is desirable to add in an amount of 5 parts by weight or more, preferably 7 parts by weight or more and 120 parts by weight or less.

In the present invention, other resin polymers and the like can be added to the toner in addition to the above copolymer. Examples include styrene copolymers such as polystyrene, polystyrene-butadiene copolymers, styrene-acrylic copolymers, and ethylene copolymers such as polyethylene, polyethylene-vinyl acetate copolymers, and polyethylene-vinyl alcohol copolymers. Examples include polymers, phenolic resins, epoxy resins, allyl phthalate resins, polyamide resins, polyester resins, and maleic acid resins. There are no particular restrictions on the manufacturing method of any of these resins.

As the coloring material used in the toner of the present invention, conventionally known coloring materials such as carbon black, dyes, and pigments can be used.

Further, a fluidity improver such as silica or alumina may be added to the toner.

Further, when the toner of the present invention is used as a microcapsule toner, the structure of the present invention can be implemented in the core material, the shell material, or both.

〔Example〕

The content of the present invention will be explained in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Note that all "parts" on each side are parts by weight. Furthermore, the results for each side are summarized in Table 1.

Example 1 A comonomer consisting of 82 parts of styrene, 15 parts of n-butyl methacrylate, and 3 parts of dimethylaminoethyl methacrylate was copolymerized in a xylene solvent using 2 parts of a compound having the structural formula: % formula % as a polymerization initiator. , a copolymer was obtained. 100 parts of this copolymer and 60 parts of α-Fe2O3 fine particles (average particle size 0.5 μm) were mixed, jet-pulverized and classified to obtain a non-magnetic toner having an average particle size of 10 μm. The toner yield was good at 90%.

A Canon copier NP was modified to mix 8 parts of the toner with 100 parts of iron powder carrier to form a negative latent image.
・When copying was carried out using the 5000, a good sepia color image was obtained. Even after making 100,000 copies, the images did not deteriorate as long as the toner was properly replenished.

Furthermore, there was no toner scattering and the copying machine was not soiled. Furthermore, the obtained image did not peel off when bent, and was strongly fixed.

Same thing, 15℃, 10%RH or 35℃, 90
When the test was carried out under a special environment of %RH, good images were obtained.

Furthermore, even after being left in the same monkey environment for three months, there was no deterioration in image quality.

Example 2 100 parts of the copolymer obtained in Example 1, 10 parts of titanium oxide fine particles (average particle size 0.4μ), and 7 parts of rhodamine lake pigment were kneaded, jet-pulverized and classified, and the average particle size was 1
A 2μ toner was obtained. Thereafter, the same test as in Example 1 was conducted, and as in Example 1, good results were obtained.

Comparative Example 1 The same operations as in Example 1 were performed except that α-Fe203f was not included. As a result, image quality, durability,
Although the fixing properties were good, toner scattering was significant.

Comparative Example 2 A comonomer consisting of 81 parts of styrene, 18 parts of butyl methacrylate, and 1 part of dimethylaminoethyl methacrylate was used in Example 1, using 2 parts of the same polymerization initiator as in Example 1.
A copolymer was obtained according to the method of . Other procedures were carried out in the same manner as in Example 1, and the yield of toner with an average particle size of 10 μm was as high as 60 μm.

Further, when a copying test was conducted in the same manner as in Example 1, the obtained image had a lot of fog and the fixability was also poor.

Comparative Example 3 A comonomer consisting of 70 parts of styrene, 12 parts of butyl methacrylate, and 18 parts of dimethylaminoethyl methacrylate was used in Example 1.
Copolymerization was carried out according to the method of Example 1 using 2 parts of the same polymerization initiator as in Example 1 to obtain a copolymer.

The following was carried out in the same manner as in Example 1, and although both the toner yield and the image were good, the image density decreased significantly at 35°C and 90% RH, and the image almost disappeared after being left for one month. .

Comparative Example 4 A copolymer was obtained by carrying out the method of Example 1 except that 2 parts of benzoyl peroxide was used as a polymerization initiator. This copolymer was colored and made into a toner in the same manner as in Example 1, but stable pulverization could not be achieved. Also, 15℃, 10
In a cold RH environment, it will charge up and the temperature will drop to 35℃.
, under an RH environment of 90°, the image density was significantly lowered and the charging property was not stable at all.

Example 3 A comonomer consisting of 80 parts of styrene, 16 parts of 2-ethylhexyl acrylate, and 8 parts of diethylaminoethyl methacrylate was copolymerized in a xylene solvent using 1.5 parts of a compound of the structural formula as a polymerization initiator. , a copolymer was obtained.

60 parts of this copolymer, 40 parts of styrene-butadiene copolymer, 15 parts of alumina fine particles (average particle size 50 mμ), and 5 parts of rhodamine pigment were melted, mixed, jet-pulverized and classified to obtain an average particle size. A 14μ toner was obtained. The toner yield was good at 88 cm.

When 5 parts of this toner and 100 parts of iron powder carrier were completely mixed and a copying test was conducted in the same manner as in Example 1, good results were obtained as in Example 1.

Example 4 A copolymer was prepared in the same manner as in Example 3 using a comonomer consisting of 80 parts of styrene, 8 parts of n-butyl acrylate, and 12 parts of diethylaminoethyl acrylate, using 4 parts of the same polymerization initiator as in Example 3. I got it.

100 parts of this copolymer, 80 parts of molybdenum sulfide fine particles (average particle size 0.4 μm), and 6 parts of an azo red pigment were melted, kneaded, jet-pulverized and classified to obtain a toner with an average particle size of 10 μm with 92% Obtained in high yield.

When 3 parts of this toner and 100 parts of ferrite carrier were mixed and a copying test was conducted in the same manner as in Example 1, the image quality and
Similar to Example 1, good results were obtained in terms of durability, storage stability, fixability, and environmental dependence.

Example 5 Copper iodide fine particles (average particle size 1μ) were used instead of molybdenum sulfide.
) Except for using 30 parts, the same procedure as in Example 4 was carried out, and similarly good results were obtained.

Claims (3)

[Claims] (1) A copolymer obtained by containing an aminoacrylic monomer in an amount of 2 to 15% by weight in the total constituent components and using a compound represented by the following structural formula (I) as a polymerization initiator. It is characterized by containing a polymer and one or more of metals, metal oxides, metal sulfides, and metal halides, and having a saturation magnetization of 10 emu/g or less in an external magnetic field of 5000 Oe. Positively chargeable toner. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) [However, in the formula, R_1, R_2, R_3, and R_4 are each a saturated hydrocarbon group having 1 to 8 carbon atoms, and at least one of them is One group has two or more carbon atoms. ] (2) Positive charging according to claim 1, characterized in that the binder resin contains 30% by weight or more of the copolymer obtained using the compound represented by the structural formula (I). sex toner. (3) The content of at least 5 parts by weight of one or more of metals, metal oxides, metal sulfides, and metal halides is based on 100 parts by weight of the binder resin. The positively chargeable toner according to item 1.