JPH0616183B2 - Positively charged toner - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a dry toner used in electrophotography, electrostatic recording, electrostatic printing, and the like, and more specifically, contains a magnetic substance such as magnetite. Without being concerned with a substantially non-magnetic positively charging toner.

[Description of Prior Art]

Conventionally, as a developing method using a non-magnetic toner in the electrophotographic method, for example, the cascade method described in US Pat.No. 2,618,552, for example, US Pat.
Although methods such as the powder cloud method described in No. 221,766 are also known, in general, a non-magnetic toner as shown in U.S. Pat. In order to convey the toner to the toner, a method of mixing the toner with magnetic particles such as iron powder and ferrite powder, that is, a substantially non-magnetic toner and magnetic particles are mixed to form a magnetic brush. A so-called two-component magnetic brush developing method, which develops an electrostatic charge image by rubbing the surface of a photoreceptor having an electrostatic charge image, is widely known. In this method, the substantially non-magnetic toner must be kept in a state of being uniformly mixed with the magnetic particles in the developing section, and the force for achieving this state is mainly electrostatic. Gravity and physical adhesion are dominant. That is, it is required that the electrostatic charge amount and the triboelectric charging ability of the toner be precisely controlled. It is well known that a search has been made to find an optimum positive charge controllable resin and a positively chargeable resin in order to precisely control the chargeability of the positively chargeable toner. In recent years when a color image is desired, since the resin itself is colorless, it is strongly desired to develop a suitable positively chargeable resin that can uniformly and strongly positively charge the toner and can be applied to a color toner. is there.

However, a uniform resin for positively charging toner has not been found so far, especially for positively charging toner, and any of the conventionally known resins has a problem and is not sufficiently satisfactory. . For example, the positively chargeable resin shown in the example described in JP-B-47-41931 is a mechanically fragile resin because the amino component controlling the positive chargeability is excessive.
Mechanical strength, durability, required as a binder resin for toner,
Furthermore, there are problems in terms of stable productivity.
Further, when the positively chargeable resin shown in the examples described in JP-A-54-143647 is used as the binder resin for toner, the pulverizability in the pulverization step during the production of toner particles is improved. However, there is a problem that it is difficult to maintain a good balance with the fixability in fixing the toner particles, and only so-called sticky toner can be obtained. Further, in the case of the positively chargeable resin described in JP-A-58-72950, since the amount of the amino component is small, it often becomes too hard as a binder resin for toner, and a stable positive charge is obtained. There is a problem that it is difficult to obtain the property. As described above, the conventional binder resin for positively chargeable toner, which had appropriate positive chargeability, is required to have the durability, heat stability, fixability, and storage property required for the binder resin for toner. sex,
The reality is that a positively chargeable resin that satisfies all the requirements for cleaning the photoreceptor surface and productivity is not possible. That is, all of the conventionally known positively chargeable resins mainly have a charge control role, and it is extremely unsuitable to use them as the main binder resin of the toner. Incidentally, in particular, in the case of the toner used in the above-mentioned two-component magnetic brush developing method, since it is a positively chargeable non-magnetic toner consisting essentially of an organic substance containing no magnetic substance mixed with hard magnetic particles, the main binding Since the resin is required to have a considerable physical strength, a positively chargeable resin suitable for this has not been found so far, and therefore an example is found for a toner using such a suitable resin as a main binder resin. Absent.

In addition, regarding the conventional non-magnetic positively chargeable toner, in general, although the chargeability, fluidity and the like can be controlled with respect to the developing property, for example, prevention of an unexpected situation such as toner scattering Is not sufficient, and a toner that cannot be collected by a magnetic force may cause a serious problem in some cases.

[Object of the Invention]

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

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

Still another object of the present invention is to use another polymer, a compatibility with a colorant, a copolymer excellent in affinity and an inorganic particle in combination, so that fine particle formation is easy, and productivity is also improved. The purpose of the present invention is to provide a positively chargeable toner rich in toner.

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

Still another object of the present invention is to provide a positively chargeable toner having an excellent fixing property.

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

Still another object of the present invention is to provide a toner having excellent cleaning properties which does not cause damage to the surface of the photoconductor or filming.

Still another object of the present invention is to provide a toner having good positive chargeability.

[Structure of the Invention, Effect] To achieve the above-mentioned object of the present invention, the positively chargeable toner of the present invention contains an amino acrylic monomer as a constituent in an amount of 2 to 15 wt% in all constituents, Structural formula as a polymerization initiator: [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 has 2 or more carbon atoms. belongs to. ] A copolymer obtained by using a compound represented by
r, Mn, Fe, Co, Ni, Cu, Zn, Ti, B
a, Ce, A, V, Mo, Ag, In, Sn, Sb,
A metal selected from the group consisting of W, Pt, Au and Cd,
It contains one or more of a metal oxide of the metal, a metal sulfide of the metal, and a metal halide of the metal, and has a saturation magnetization of 10 em in an external magnetic field of 5000 oersted (Oe).
It is characterized by being u / g or less.

The present inventors have conducted diligent research to eliminate the above-mentioned various problems with the conventional positively chargeable toner and develop an optimum positively chargeable toner, and as a result, use a compound represented by the structural formula (I). The obtained copolymer is made of Cr, Mn, Fe, Co, N
i, Cu, Zn, Ti, Ba, Ce, A, V, Mo,
Binder resin for toner together with particles of metal selected from the group consisting of Ag, In, Sn, Sb, W, Pt, Au and Cd, metal oxide of the metal, metal sulfide of the metal or metal halide of the metal. When used as a product, they both act in an additive manner to bring about excellent melt-kneading properties, and have moderate hardness, viscosity, and brittleness characteristics, and are rich in mechanical pulverizability, melt-spray granulation properties, etc. However, it is easy to atomize the toner, that is, the toner productivity is excellent, and it goes without saying that the obtained toner has stable positive chargeability, durability for long-term continuous use as a toner, and fixability, Furthermore, it has excellent storage stability under special environments such as high temperature and high humidity, low temperature and low humidity, and very little toner scattering during the development, transfer, and fixing processes. Amorph Assilico Or damage the photosensitive member surface consisting of such, it found a fact that there will be no problems such as Fuirumingu, the present invention was allowed to reach completion based on the fact of it, and the like.

Amino acrylic monomer used in the copolymer of the present invention,
Those represented by the following structural formula (II) are preferable.

[However, R ₅ is a hydrogen atom, a methyl group or an ethyl group, R ₆ is a substituted or unsubstituted alkylene group having 1 to 4 carbon atoms, and R ₇ and R ₈ are each a carbon number. 1-6
A substituted or unsubstituted alkyl group or a phenyl group. As the amino acrylic monomer represented by the structural formula (II), specifically, dimethylaminoethyl acrylate,
Acrylate derivatives such as diethylaminoethyl acrylate, dibutylaminoethyl acrylate, N-ethyl-N-phenylaminoethyl acrylate, and dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, dibutylaminoethyl methacrylate, N-ethyl-N-phenylaminoethyl A methacrylate derivative such as methacrylate can be used.
Considering the effects on the hardness and viscosity of the copolymer obtained, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, diethylaminomethyl acrylate, and dimethylaminoethyl methacrylate are particularly preferable.

As the constituent component other than the above amino acrylic monomer of the copolymer used in the present invention, all conventionally known monomers can be used, but generally vinyl monomers, particularly styrene- It is desirable to contain the acrylic comonomer in an amount of 70% by weight or more. Specific examples of the styrene-based monomer include styrene, vinyltoluene, α-methylstyrene, and the like, and specific examples of the acrylic-based monomer include acrylic acid, methyl acrylate, and the like. Examples thereof include ethyl, propyl, butyl, and 2-ethylhexyl esters, and methacrylic acid and methacrylic acid methyl, ethyl, propyl, butyl, and 2-ethylhexyl esters. Among these, particularly preferable ones have a Tg (glass transition point) of at least 30 ° C. of the styrene-based monomer and the homopolymer.
It is a copolymer composed of the following acrylic acid or methacrylic acid ester and the amino acrylic monomer.

The polymerization initiator used in the copolymer of the present invention has a structural formula
Although all compounds represented by (I) can be used, in order to appropriately adjust the hardness, viscosity, brittleness, etc. of the resulting copolymer, as R ₁ , R ₂ , R ₃ , and R ₄ , -CH _3, -
_{CH 2 CH 3, -CH 2 CH} 2 CH 3, -CH (CH 3) 2,
_{-CH 2 CH 2 CH 2 CH 3} , -CH (CH 3) CH 2 C
_{H 3, -CH 2 CH (CH} 3) 2, -C (CH 3) 3, -CH
_{2 CH 2 CH 2 CH 2 CH} 3, -CH 2 CH 2 CH 2 CH 2 CH 2
_{CH 3, -CH 2 CH (CH} 2 CH 3) CH 2 CH 2 CH 2 C
H ₃ , It is desirable to appropriately select one kind or two or more kinds from such groups. Further, all of R ₁ , R ₂ , R ₃ and R ₄ are -CH.
_In the case of ₃ groups, the effect of adding the initiator is unlikely to appear in the mechanical and thermal properties of the copolymer, and it becomes difficult to control the physical properties satisfactorily, which is not preferable.

The above-mentioned copolymer used in the present invention is preferably contained in the toner in an amount of 30% by weight or more, more preferably 50% by weight or more, in order to fully exert its function.

Metals used in the present invention, namely, Cr, Mn, Fe,
Co, Ni, Cu, Zn, Ti, Ba, Ce, A,
V, Mo, Ag, In, Sn, Sb, W, Pt, Au and Cd are all stable at room temperature and do not have strong magnetism. In the present invention, these metals may be an alloy of the metal or a eutectic of a metal compound of the metal. These inorganic substances are used in the form of particles, and since they are uniformly dispersed in the toner, it is desirable that the particle size is 5 μm or less, preferably 3 μm or less.

In order to exert the above-mentioned effects, such inorganic substance particles are added to the toner binder resin in an amount of 5 parts by weight.
It is desirable to add it in the range of 7 parts by weight or more, preferably 7 parts by weight or more and 120 parts by weight or less.

In the present invention, in addition to the above-mentioned copolymer, other resin polymers and the like can be added to the toner. Examples thereof include styrene-based copolymers such as polystyrene, polystyrene-butadiene copolymers, styrene-acrylic copolymers, and ethylene-based copolymers such as polyethylene, polyethylene vinyl acetate copolymers and polyethylene alcohol copolymers. Coalesced, phenolic resin, epoxy resin,
Examples include allyl phthalate resin, polyamide resin, polyester resin, and maleic acid resin. The manufacturing method of any of these resins is not particularly limited.

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.

Furthermore, when the toner of the present invention is used as a microcapsule toner, the constitution of the present invention can be carried out by the core material, the shell material, or both.

〔Example〕

The contents of the present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In addition, all "parts" in each example are parts by weight. Further, the results of each example are summarized in Table 1.

Example 1 Styrene 82 parts n-butyl methacrylate 15 parts Dimethylaminoethyl methacrylate 3 parts A comonomer of the structural formula: 2 parts of the above compound was used as a polymerization initiator and copolymerized in a xylene solvent to obtain a copolymer. With 100 parts of this copolymer,
60 parts of α-Fe ₂ O ₃ fine particles (average particle size 0.5 μ) were kneaded, crushed with jet and classified to obtain a non-magnetic toner having an average particle size of 10 μ.
The toner yield was as good as 90%.

Canon copying machine NP-500 modified by mixing 8 parts of the toner and 100 parts of iron powder carrier to form a negative latent image
When it was put into 0 and copied, a good sepia color image was obtained. The image was not deteriorated even after 100,000 copies were made by appropriately replenishing the toner.
Further, the toner was not scattered and the copying machine was not soiled. Furthermore, the obtained image did not peel off due to bending and was strongly fixed.

When the same operation was performed under a special environment of 15 ° C., 10% RH or 35 ° C., 90% RH, good images were obtained.

Moreover, the image quality did not deteriorate even after being left for 3 months in the same environment.

Example 2 100 parts of the copolymer obtained in Example 1, 10 parts of titanium oxide fine particles (average particle size 0.4 μ), and Rhodamine lake pigment 7
The resulting mixture was kneaded, crushed with a jet, and classified to obtain a toner having an average particle diameter of 12 μ. Then, when the same test as in Example 1 was performed, the same good result as in Example 1 was obtained.

Comparative Example 1 Example 1 except that no α-Fe ₂ O ₃ was contained.
When the same operation as that of 1. was carried out, the image quality, the durability and the fixing property were good, but the toner scattering was remarkable.

Comparative Example 2 Copolymer according to the method of Example 1 using 2 parts of the same polymerization initiator as in Example 1 with a comonomer consisting of 81 parts of styrene, 18 parts of butyl methacrylate and 1 part of dimethylaminoethyl methacrylate. Got Others were performed in the same manner as in Example 1, and the yield of the obtained toner having an average particle diameter of 10 μ was 60%, which was not good.

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 fixing property was poor.

Comparative Example 3 A comonomer consisting of styrene 70 parts butyl methacrylate 12 parts dimethylaminoethyl methacrylate 18 parts was copolymerized according to the method of Example 1 using 2 parts of the same polymerization initiator as in Example 1, A copolymer was obtained.

When the following steps were performed in the same manner as in Example 1, both the toner yield and the image were good, but the image density was remarkably reduced under the environment of 35 ° C. and 90% RH, and the image almost disappeared when left for 1 month.

Comparative Example 4 A copolymer was obtained by the method of Example 1 except that 2 parts of benzoyl peroxide was used as a polymerization initiator. This copolymer was colored with a color and was converted into a toner in the same manner as in Example 1, but stable pulverization could not be performed. Also, 15 ℃, 10% RH
Under the environment, it will charge up, 35 ℃, 90% R
Under the H environment, the chargeability was not stable at all, as the image density was remarkably reduced.

Example 3 Styrene 80 parts 2-Ethylhexyl acrylate 16 parts Diethylaminoethyl methacrylate 8 parts A comonomer having the structural formula: 1.5 parts of the compound of 1 was used as a polymerization initiator and copolymerized in a xylene solvent to obtain a copolymer.

60 parts of this copolymer and 40 parts of styrene-butadiene copolymer
Parts, 15 parts of alumina fine particles (average particle size 50 mμ), and 5 parts of rhodamine-based pigment were melted, kneaded, jet milled and classified to obtain a toner having an average particle size of 14 μ. The toner yield was as good as 88%.

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

Example 4 Copolymer in the same manner as in Example 3 except that 4 parts of the same polymerization initiator as in Example 3 was used as a comonomer consisting of 80 parts of styrene, 8 parts of n-butyl acrylate, and 12 parts of diethylaminoethyl acrylate. Got

100 parts of this copolymer, 80 parts of molybdenum sulfide fine particles (average particle size 0.4μ) and 6 parts of azo red pigment are melted, kneaded, jet crushed and classified to obtain 92 toner particles having an average particle size of 10μ.
Obtained in high yield of%.

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

Example 5 Instead of molybdenum sulfide, copper iodide fine particles (average particle size 1
The same procedure was performed as in Example 4 except that 30 parts of μ) was used, and similarly good results were obtained.

Claims (3)

[Claims] 1. A constituent comprising an aminoacrylic monomer in an amount of 2 to 15% by weight in all constituents, and a compound represented by the following structural formula (1) is used as a polymerization initiator. The resulting copolymer and Cr, Mn, Fe, Co, N
i, Cu, Zn, Ti, Ba, Ce, Al, V, Mo,
One or more of a metal selected from the group consisting of Ag, In, Sn, Sb, W, Pt, Au and Cd, a metal oxide of the metal, a metal sulfide of the metal and a metal halide of the metal. And a saturation charge in an external magnetic field of 5,000 Oersted (Oe) is 10 emu / g or less. [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 a hydrocarbon group having 2 or more carbon atoms. belongs to. ] 2. A binder resin containing 30% by weight or more of a copolymer obtained by using the compound represented by the structural formula (I). Positively chargeable toner. 3. One or more of the metal, the metal oxide of the metal, the metal sulfide of the metal, and the metal halide of the metal are contained in an amount of 5 parts by weight per 100 parts by weight of the binder resin. Claim 1 characterized by containing the above
The positively chargeable toner according to the item 1.