JP2681859B2 - Magnetic toner and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to electrophotography, electrostatic recording,
The present invention relates to a magnetic toner for developing an electrostatic image in electrostatic printing and a method for manufacturing the magnetic toner.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic method, US Pat.
Many methods are known as described in Japanese Patent Publication No. 297691, Japanese Patent Publication No. 42-23910 and Japanese Patent Publication No. 43-24748, but generally, a photoconductive substance is used and various methods are used. An electrical latent image is formed on the photoconductor, the latent image is developed with toner, and the toner image is transferred to a transfer material such as paper, if necessary, and then heat, pressure, heat pressurization or The toner is fixed by a solvent vapor or the like to obtain a copy, and the toner remaining on the photoreceptor without being transferred is removed by various methods, and the above steps are repeated.

In recent years, such a copying apparatus is not an office processing copying machine for simply copying an original, but as an information output device linked to another information processing device by the introduction of digital technology, or as a multifunctional device. By making it easier to process and edit image information, it began to be used as a printer for creating new original manuscripts. Furthermore, the use as personal copying machines for individuals is also increasing.

Therefore, higher speed, higher image quality, smaller size and lighter weight have been pursued, and higher reliability has been strictly pursued. On the other hand, copiers and printers are being pursued for cost reduction, and are being configured with simpler elements in various respects. As a result, the performance required for toner used in copying machines and printers has become high, and unless improvement in toner performance can be achieved, an excellent electrophotographic apparatus cannot be established.

For example, various methods have been developed for the process of fixing a toner image on a recording material such as transfer paper. Currently, the most common method is a pressure heating method, and a heat roll fixing method is often used.

In the heat roll fixing method, the toner image surface of the recording material is heated and pressed while being in contact with the surface of a heat roller having a surface formed of a material having releasability for toner.
Fixing is done by letting it pass. In this method, the surface of the heat roller and the toner image on the recording material come into contact with each other under pressure, so that the thermal efficiency at the time of fusing the toner image on the recording material is extremely good, and rapid fixing is possible. it can.

However, the heat roll fixing requires a wait time for the heat roller to reach a predetermined temperature, and the wait time is shortened and the toner image is fixed on the recording material as the speed of the copying machine increases. The heating time is shortened, and fixing defects are likely to occur due to a decrease in the temperature of the heating roller as the recording material passes.

Further, since the surface of the heat roller and the toner image come into contact with each other under pressure in a molten state of the toner, a part of the toner image adheres and transfers to the surface of the heat roller and retransfers to the next recording material. The offset phenomenon is likely to occur.

Therefore, in order to achieve the reduction of the wait time, the speeding up of the fixing, and the high image quality while maintaining the excellent fixing property of the toner image to the recording material without the image stain due to the offset phenomenon, Low-temperature fixing performance and anti-offset performance of toner are important.

Japanese Patent Publication No. Sho 63-32182 has been proposed for the purpose of improving the low-temperature fixability and fluidity of toner and the stain resistance of toner holding members such as photoconductors. This publication proposes a toner containing as a binder resin component of the toner, a vinyl polymer having at least one local maximum in each specific region of low molecular weight and high molecular weight. The toner has a relatively large amount of a low molecular weight component to improve the fixability. However, when the present inventors proceed with further studies, both the maximum peaks on the low molecular weight side and the high molecular weight side are peaked. In the meantime, there are many components that cannot effectively contribute to fixability, and there is still room for improvement not only in fixability but also in offset resistance.

On the other hand, in order to solve the problem of the offset phenomenon, a method of adding a releasing agent such as low molecular weight polyethylene or low molecular weight polypropylene to the toner is conventionally known. However, it is usually difficult to produce a toner containing the release agent in the best condition. In the conventional manufacturing of toner, after premixing a binder resin, a coloring agent such as a magnetic material, other additives as necessary, and a release agent,
A toner having a desired particle size is obtained through a process of heating, melting and kneading, cooling the kneaded product, and then pulverizing and classifying. However, in the manufacturing method, since the compatibility between the binder resin and the release agent at the time of heating and melting is poor, particles containing the release agent as a main component are generated during pulverization, and the release agent is contained in the obtained toner particles. It is difficult to obtain a toner that is sufficiently uniformly dispersed. Furthermore, particles formed only with the release agent or particles containing the release agent as a main component are likely to be generated during pulverization. When a large amount of the release agent is present among the toner particles as the release agent particles which are singly released, the obtained toner tends to decrease the release effect.

The above-mentioned Japanese Patent Publication No. 63-32182 proposes a toner containing, by kneading, an ethylene-based olefin homopolymer or copolymer which can serve as a release agent. However, in the toner, since the binder resin contains a relatively large amount of the low molecular weight component, shearing force is not easily applied in the melt kneading of the ethylene-based olefin polymer with other components, and the toner of the polymer is obtained. Dispersion in the particles is likely to be insufficient. Even if the release agent is dispersed and mixed in the toner particles, the combination of the binder resin and the release agent is not sufficient in terms of fixability and anti-offset property. The releasability of does not sufficiently act, and the releasability of the toner tends to decrease.

In order for the toner to exert a sufficient releasing effect, a large amount of the releasing agent may be added, but this causes a further increase in the releasing agent particles released between the toner particles. ,
When the toner is applied to a copying machine, the fluidity in the developing device is deteriorated, the surface of the toner carrier such as carrier particles and developing sleeve is contaminated, and the toner is apt to adhere to the non-image area during the development, and Due to adverse effects such as filming on the developed image, the developed image is easily deteriorated.

Heretofore, JP-A-62-195683 has been proposed for the purpose of uniformly dispersing a release agent in a toner. This proposes a toner in which a low molecular weight wax is mixed with a binder resin solution and desolvated under heating to use the dispersion state of the wax in the toner particles. In the toner, the weight average molecular weight (Mw) of the binder resin is 23,000 or less, and the binder resin is composed of a polymer having a very low molecular weight. However, according to the study by the present inventors, in the binder resin which does not contain a high molecular weight component and only has a low molecular weight like the binder resin, the viscosity increase at the time of desolvation in a binder resin solution containing a wax is increased. Therefore, the low molecular weight wax is likely to re-aggregate and precipitate as large particles in the binder resin after desolvation or after cooling the binder resin in the next step due to its poor compatibility. The dispersed state of the release agent of No. 1 still leaves room for improvement. Further, since the toner containing the binder resin does not have a high molecular weight component, the elasticity of the heat-melted toner at the time of fixing is too low, and thus the offset resistance performance is difficult to reach a high level.

Further, Japanese Patent Publication No. 2-235069 has been proposed for the purpose of improving fixability, anti-offset property, and background stain during development. This is because the binder resin has two peaks in the molecular weight distribution, and the dispersion ratio of each of the low molecular weight region and the high molecular weight region is reduced with the minimum value between the two peaks as the base point to reduce the heat of the toner. It aims to improve cohesiveness and pulverizability during toner production. However, in the molecular weight distribution of the binder resin, particularly when the dispersion ratio in the high molecular weight region is small, the components having a molecular weight larger than the peak on the high molecular weight side are reduced, so that the melt viscosity on the high molecular weight side is reduced and It is difficult to fully demonstrate the offset performance.

[0016]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems.

An object of the present invention is to provide a magnetic toner excellent in low-temperature fixing performance and anti-offset property, and a manufacturing method thereof .

An object of the present invention is to provide a magnetic toner excellent in blocking resistance and a method for producing the magnetic toner.

An object of the present invention is to provide a magnetic toner in which free olefin fine particles are not contained between magnetic toner particles or in a very small amount, and a method for producing the same.

An object of the present invention is to provide a magnetic toner having excellent durability and a method for producing the same.

An object of the present invention is to provide a magnetic toner and a magnetic toner which hardly pollute the developing sleeve surface and the photosensitive drum surface.
It is to provide a manufacturing method of.

[0022]

SUMMARY and operation for solving] The present invention is a magnetic toner comprising a binder resin having at least a styrenic polymer or styrenic copolymer, a polyolefin, or wax, and a magnetic material, forming Resin and magnetic material
Before the and are mixed, the polyolefin or wax
Yes is previously dispersed in a binder resin, said binder resin is a non-crosslinked polymer, the tetrahydrofuran binding Chakujushi solvent
To GPC (gel permeation chromatography)
The chromatogram measured by
The maximum peak height (H1) on the low molecular weight region side and the maximum peak height on the high molecular weight region side (H1) have at least one maximum in each of the 20,000 to 200,000 and 200,000 to 1,000,000 regions. H3) and the height of the minimum value (H2) between the both peaks satisfy the relationship of H1: H2: H3 = 3 to 25: 1: 1.5 to 12, and the weight average molecular weight (Mw) and the number average are molecular weight (Mn) but relates to a magnetic toner, wherein the Ru Mw / Mn = 15 to 80 der.

Further, the present invention provides (a) low molecular weight polymerization
Body, (b) high molecular weight polymer, (c) polyolefin or
Is mixed with wax and (d) solvent,
Molecular weight polymer, high molecular weight polymer, polyolefin or wax
To prepare a mixture in which the
The medium is removed and the polyolefin or wax is dispersed.
Generating a binder resin which is a polyolefin or wax
The binder resin in which the particles are dispersed and the magnetic material are kneaded,
The kneaded product was cooled, pulverized and cooled kneaded material, the pulverized product
Classify to at least styrene polymer or styrene
Binder resin having a system-based copolymer and polyolefin or
A magnetic toner containing wax and a magnetic material,
The binder resin is a non-crosslinked polymer and the binder resin tetrahydrate
GPC (gel permeation ink)
Chromatogram measured by chromatography)
Of the molecular weight range of 5,000 to 20,000 and 200,000 to 1,000,000
Has at least one local maximum in each of the regions of
Maximum peak height (H1) on the molecular weight region side and high molecular weight region
Height of maximum peak on the region side (H3) and minimum between both peaks
The height of the value (H2) is H1: H2: H3 = 3 to 25:
1: The relationship of 1.5 to 12 is satisfied, and the weight average molecular weight is
(Mw) and number average molecular weight (Mn) are Mw / Mn = 1
5 to 80, a method for producing a magnetic toner
Regarding

In order to impart excellent low-temperature fixing performance and offset resistance to the toner at the same time, the inventors of the present invention control the molecular weight distribution so that the binder resin effectively works for each performance. , It is necessary that the release agent be contained in the toner in order to work effectively, but in the conventional toner, it does not contribute to the fixing performance between the maximum peaks on both the low molecular weight side and the high molecular weight side of the binder resin. We found that the problem was that there were too many inactive components and that the uniform dispersibility of the release agent in the toner was not yet fully resolved. The invention has been reached.

The magnetic toner of the present invention can achieve the above-mentioned object by reducing the viscosity at the time of heating and melting the toner by accelerating the low-temperature fixability while the binder resin contained therein is a non-crosslinked polymer. , Mw in the molecular weight distribution of the binder resin
By increasing the value of / Mn, the toner melt elasticity is enhanced, offset resistance is secured, and in the molecular weight distribution, the maximum peak P1ma on the low molecular weight side and the maximum peak on the high molecular weight side are obtained.
The height of the minimum value V2min between x and P3max (H
By controlling 2) to be low, it is possible to reduce the amount of components that cannot sufficiently contribute to the fixability, so that the entire structure of the molecular weight distribution of the resin effectively acts on the fixability and the offset resistance. Conceivable. As a result, the magnetic toner of the present invention has improved low-temperature fixability and offset resistance. Further, when a polyolefin as a release agent is mixed and contained in the binder resin in the presence of a component on the high molecular weight side in advance, re-aggregation of the release agent after dispersion is unlikely to occur and precipitated particles are in a very small state. Since the particles of the releasing agent are not present between the toner particles because they are uniformly dispersed, or even if they are present, the amount of the releasing agent is extremely small, so that the blocking resistance,
It is considered that fluidity, durability and image stability can be obtained.

The binder resin used in the present invention is a non-crosslinked polymer, and the chromatogram of the binder resin measured by gel permeation chromatography (GPC) is
Molecular weight range of 5,000 to 20,000 and molecular weight of 200,000 to 100
Has at least one local maximum in each of the ten thousand regions,
Height of maximum peak P1max on the low molecular weight region side (H1)
And the height of the maximum peak P3max on the high molecular weight region side (H
3) and the height of the minimum value V2min between the both peaks (H
2) and H1: H2: H3 = 3 to 25: 1: 1.5 to 1
It is necessary to satisfy the relationship of 2 and have a weight average molecular weight (Mw) and a number average molecular weight (Mn) of Mw / Mn of 15 to 80 and further contain a polyolefin. Furthermore, in the chromatogram measured by the GPC, the molecular weight of 8,000 to 16,000 and 400,000 to
It has at least one local maximum in each region of 800,000 and the height of the maximum peak P1max on the low molecular weight region side (H
1) and the height (H3) of the maximum peak P3max on the high molecular weight region side and the height (H) of the minimum value V2min between the both peaks.
2) and H1: H2: H3 = 6 to 20: 1: 3 to 9 are satisfied, and the weight average molecular weight (Mw) and the number average molecular weight (Mn) have a value of Mw / Mn of 22 to 60. Is more preferable.

Further, in the GPC chromatogram, the height H1 is preferably higher than the height H3,
Furthermore, a binder resin containing 5 to 30% (more preferably 7 to 25%) of a high molecular weight component existing in a region of a molecular weight of 500,000 or more is preferable because it simultaneously satisfies both fixability and offset resistance.

In the chromatogram of the binder resin measured by GPC, when the molecular weight at the maximum peak position on the low molecular weight side is less than 5,000, the blocking resistance of the toner is lowered and the toner holding member such as a developing sleeve is deteriorated. Contamination and fogging tend to occur during development, and conversely, when the molecular weight at the maximum peak position on the low molecular weight side exceeds 20,000, low-temperature fixability deteriorates, which is not preferable. If the molecular weight at the maximum peak position on the high molecular weight side is less than 200,000, blocking resistance and offset resistance are reduced, and conversely, if the molecular weight at the maximum peak position on the high molecular weight side exceeds 1 million, the toner is heated and melted. It is not preferable because the viscosity starts to increase and the low temperature fixability deteriorates.
If the maximum peak height (H1) on the low molecular weight region side is less than 3, or if the maximum peak height (H3) on the high molecular weight region side exceeds 12, low temperature fixability deteriorates, which is not preferable. On the contrary, when the H1 exceeds 25 or the H3 is less than 1.5, the offset resistance and the dispersibility of the release agent are deteriorated, which is not preferable. When the weight average molecular weight (Mw) / number average molecular weight (Mn) is less than 15, the offset resistance tends to be poor, and when it exceeds 80, the low temperature fixing property tends to be poor, which is not preferable.

The high molecular weight polymer preferably contains 40 to 80% of a component having a molecular weight of 500,000 or more.

As a preferred method for producing the binder resin of the present invention, in the chromatogram of GPC, the molecular weight at the peak position of the maximum value is in the range of 5,000 to 20,000 and Mw / Mn is 3.0 or less. In a polymer solution prepared by dissolving the low molecular weight polymer in a good solvent, or in a solution prepared by the solution polymerization method of the low molecular weight polymer, the molecular weight at the peak position of the maximum maximum value is 200,000 to 1,000,000. In the region, the component in the region of molecular weight 500 to 100,000 is 30 wt% or less, and the molecular weight component in the region of molecular weight 500,000 or more is 40-8
A method of adding 0% by weight of a high molecular weight polymer and a polyolefin, heating and dissolving them, and then removing the solvent can be mentioned.

The low molecular weight polymer as described above can be obtained by any of solution polymerization method, suspension polymerization method, bulk polymerization method and emulsion polymerization method, but a low molecular weight polymer solution in the next step is obtained. In consideration of this, it is preferable to prepare the low molecular weight polymer by the solution polymerization method and use the solution at the time of solution polymerization. Examples of the solvent used in the solution polymerization method include hydrocarbon-based organic solvents such as benzene, xylene, and cyclohexane; ketone-based organic solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; amide-based organic solvents such as dimethylformamide and dimethylacetamide. can give. These solvents can also be used as good solvents for dissolving the low molecular weight polymer to obtain a polymer solution.

As the initiator for polymerizing the polymerizable monomer, for example, t-butylperoxy 2-ethylhexaneate, t-butylperoxylaurate, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, Di-t-butyl peroxide,
t-butyl cumyl peroxide, diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 2,2 A radical initiator such as'-azobis (4-methoxy-2,4-dimethylvaleronitrile) is used alone or as a mixture. The amount of radical polymerization initiator used is
0.1 with respect to the polymerizable monomer constituting the low molecular weight polymer
-15 wt%, preferably 1-10 wt% is suitable.

On the other hand, as a method for obtaining the high molecular weight polymer satisfying the above-mentioned molecular weight conditions, the production of a polymer having a molecular weight of 100,000 or less is suppressed during synthesis by selecting a polymerization initiator of a polymerizable monomer. Alternatively, the content of the polymer having a molecular weight of 100,000 or less can be reduced by the fractional removal of the polymer having a molecular weight of 100,000 or less; or a combination of both can be obtained.

The polymerization method may be any of a bulk polymerization method, a solution polymerization method, a suspension polymerization method and an emulsion polymerization method, but a suspension polymerization method in which a relatively high polymer is easily obtained and the molecular weight distribution is easily controlled. Is preferred.

As the initiator for polymerizing the polymerizable monomer, it is preferable to use a bifunctional radical initiator, for example, 1,1-bis (t-butylperoxy) 3,3,5-
Trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, 1,4-bis (t-butylperoxycarbonyl) cyclohexane, 2,2-bis (t-butylperoxy) octane, n-butyl 4 ，
4-bis (t-butylperoxy) valerate, 2,2
-Bis (t-butylperoxy) butane, 1,3-bis (t-butylperoxy-isopropyl) benzene,
2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3,2,5-dimethyl-
2,5-di (benzoylperoxy) hexane, di-t
-Butylperoxyisophthalate, 2,2-bis (4,4-di-t-butylperoxycyclohexyl)
Propane, di-t-butylperoxy α-methylsuccinate, di-t-butylperoxydimethyl glutarate, di-t-butylperoxyhexahydroterephthalate, di-t-butylperoxyazelate, 2,5 −
Examples thereof include difunctional radical polymerization initiators such as dimethyl-2,5-di (t-butylperoxy) -hexane, diethylene glycol bis (t-butylperoxy carbonate), and di-t-butylperoxytrimethyl adipate. These may be used alone or in combination, or may be used in combination with other radical initiators if necessary. The amount of these radical polymerization initiators used is appropriately 0.05 to 5% by weight, preferably 0.1 to 3% by weight, based on the polymerizable monomer constituting the high molecular weight polymer.

Examples of the method for fractionating the polymer component include a fractional precipitation method, a fractional dissolution method, a column fractionation method and a GPC method. Particularly, it is preferable to reduce the polymer having a molecular weight of 100,000 or less by the fractional precipitation method. As a good solvent for dissolving a high molecular weight polymer by the fractional precipitation method, benzene,
Hydrocarbon-based solvents such as xylene and cyclohexane; ketone-based solvents such as acetone, methyl ethyl ketone and cyclohexanone; ether-based solvents such as tetrahydrofuran and methyl cellosolve. Examples of the poor solvent for precipitating and precipitating the high molecular weight polymer from the solution in which the polymer is dissolved include alcohol solvents such as methanol, ethanol and iso-propyl alcohol.

As the low molecular weight polymer, a styrene-based polymer or styrene-based copolymer having a styrene component of 75 to 100% by weight is preferable in terms of developability, heat fixing property and offset resistance. More preferably, the low molecular weight polymer is a styrene-based copolymer having a styrene component of 80 to 95% by weight.

As the high molecular weight polymer, a styrene copolymer having a styrene component of 60 to 99% by weight (more preferably 70 to 90% by weight) is preferable.

As a method for obtaining the high molecular weight polymer satisfying the above-mentioned molecular weight conditions, the selection of the polymerization initiator of the polymerizable monomer suppresses the generation of the polymer having the molecular weight of 100,000 or less during the synthesis and suppresses the molecular weight. A polymer having a molecular weight of 500,000 or more is produced or distributed, or a polymer having a molecular weight of 100,000 or less is separately removed by maintaining the content of the polymer having a molecular weight of 500,000 or more. It is obtained by reducing the content of chisel or by using both of them together.

The binder resin used in the present invention is composed of a styrene polymer or a styrene copolymer. Examples of the monomer for synthesizing the styrene polymer include styrenes such as styrene, α-methylstyrene, vinyltoluene and chlorostyrene. As a monomer for synthesizing a styrene-based copolymer, in addition to the above-mentioned styrene monomer, for example, acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, octyl acrylate. Acrylic acid esters such as 2-ethylhexyl acrylate, n-tetradecyl acrylate, n-hexadecyl acrylate, lauryl acrylate, cyclohexyl acrylate, diethylaminoethyl acrylate, dimethylaminoethyl acrylate, and methacrylic acid. Acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, decyl methacrylate, dodecyl methacrylate, Methacrylic acid lauryl, cyclohexyl methacrylate, phenyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, dimethylaminoethyl methacrylate, glycidyl methacrylate, such as methacrylic acid esters of stearyl methacrylate and the like. Examples of the other monomer include acrylonitrile, 2-vinylpyridine, 4-vinylpyridine, vinylcarbazole, vinylmethyl ether, butadiene, isoprene, maleic anhydride, maleic acid, maleic acid monoesters, maleic acid diesters, vinyl acetate, etc. Can be given. These monomers may be used alone or in combination of two or more together with the styrene monomer.

In addition to the binder resin component, the toner of the present invention may contain the following compounds in a proportion smaller than the content of the binder resin component. For example, silicone resin, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, rosin, modified rosin, terpene resins, phenol resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffin.

Paraffin is used as the wax applied to the present invention.
Examples of the polyolefin include , for example, ethylene, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, a homopolymer of α-olefin, or a copolymer of two or more α-olefins. Examples thereof include coalesce and polyolefin oxides. Further, these polyolefins may be vinyl graft-modified polyolefins graft-modified with vinyl monomers such as styrene.

The vinyl-based graft modified polyolefin is composed of the above-mentioned polyolefin component and modifying component, and the modifying component is grafted to the polyolefin component. As the modifying component, a vinyl-based monomer is used. For example, as the aliphatic vinyl-based monomer, methacrylic acid and methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, 2-ethylhexyl are used. Methacrylate, lauryl methacrylate, stearyl methacrylate, dodecyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, 2-hydroxyethyl methacrylate,
Methacrylates such as 2,2,2-trifluoroethyl methacrylate, glycidyl methacrylate; acrylic acid and methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-octyl acrylate, lauryl acrylate, stearyl acrylate, Dodecyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, 2-chloroethyl acrylate, 2-hydroxyethyl acrylate, cyclohexyl acrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dibutylaminoethyl acrylate, 2-ethoxyacrylate, 1,4 Acrylates such as butanediol diacrylate; maleic acid, fumaric acid, Conic acid, citraconic acid and monoethylmalate, diethylmalate, monopropylmalate, dibutylmalate, monobutylmalate, dibutylmalate, di-2 ethylhexyl fumarate, monoethyl fumarate, di-ethyl fumarate , Dibutyl fumarate, di-2 ethylhexyl fumarate, monoethyl itaconate, diethyl itaconate, monoethyl citracone, diethyl citracone, and the like. One or more of these can be used simultaneously.

Styrene as the aromatic vinyl monomer,
o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, 2,4-dimethylstyrene, p-ethylstyrene, pn-butylstyrene,
Examples thereof include p-tert-butylstyrene, pn-dodecylstyrene, p-phenylstyrene, p-chlorostyrene and the like. These 1 type (s) or 2 or more types can be used simultaneously.

As a method for graft modification, a conventionally known method can be used. For example, a graft-modified polyolefin is obtained by reacting the above-mentioned polyolefin with an aromatic vinyl monomer and an aliphatic vinyl monomer in a solution state or a molten state under heating in the atmosphere or under pressure in the presence of a radical initiator, to cause a reaction. The grafting with the aromatic vinyl monomer and the aliphatic vinyl monomer may be carried out both at the same time or separately.

The polyolefin used in the present invention preferably has a weight average molecular weight of 2000 to 300 in high temperature GPC measurement using o-dichlorobenzene as a solvent.
00, more preferably a low molecular weight of 5,000 to 18,000.

In the magnetic toner of the present invention, the addition amount of the polyolefin to the binder resin is 10
The amount is preferably 0.1 to 20 parts by weight, more preferably 0.1 to 10 parts by weight, based on 0 parts by weight. If the amount is less than 0.1 parts by weight, the effect on offset resistance is difficult to be exerted, and if the amount is more than 20 parts by weight, the polyolefin particles precipitated in the binder resin become large and the toner blocking resistance is increased. The property is likely to deteriorate.

In the present invention, the molecular weight distribution of the chromatogram of the binder resin by GPC is measured under the following conditions using THF (tetrahydrofuran) as a solvent.

The column was stabilized in a heat chamber at 40 ° C. and THF was added as a solvent to the column at this temperature.
At a flow rate of 1 ml per minute, and the THF sample solution is added to about 100
Inject μl and measure. In measuring the molecular weight of the sample, the molecular weight distribution of the sample was calculated from the relationship between the logarithmic value and the count number of a calibration curve prepared from several kinds of monodisperse polystyrene standard samples. As a standard polystyrene sample for preparing a calibration curve, for example, a standard polystyrene sample having a molecular weight of about 10 ^{2 to} 10 ⁷ manufactured by Tosoh Corporation or Showa Denko Corporation is used, and it is suitable to use a standard polystyrene sample of at least about 10 points. . An RI (refractive index) detector is used as the detector. As the column, it is preferable to combine a plurality of commercially available polystyrene gel columns, for example, Shodex GPC KF-801, 80 manufactured by Showa Denko KK
2,803,804,805,806,807,800
Combination of P and TSKgel G10 manufactured by Tosoh Corporation
00H (H _XL ), G2000H (H _XL ), G300
0H (H _XL ), G4000H (H _XL ), G5000
H (H _XL ), G6000H (H _XL ), G7000H
(H _XL ), the combination of TSKguardcolumn can be mentioned.

In the present invention, the GPC measuring device is LC-
As GPC150C (manufactured by Waters) and columns, shodex KF-801, 802, 803, 8 is used.
04,805,806,807 and 800P (manufactured by Showa Denko KK) were used.

The sample is prepared as follows. The binder resin or the magnetic toner is put in THF, left for several hours, shaken sufficiently, and well mixed with THF (until the coalescence of the sample disappears), and the mixture is left standing for 12 hours or more. At this time, TH
The time of leaving in F is set to 24 hours or more. After that, a sample processing filter (pore size 0.45 to 0.5 μm, for example, Mysholydisk H-25-
5 The product passed through Tosoh Co., Ltd., and can be used as a sample of GPC. The sample concentration is adjusted so that the resin component is 3 to 7 mg / ml.

At the time of sample preparation, components insoluble in THF are removed, and GPC of the components soluble in THF is measured.

The overall molecular weight distribution measured by GPC of the binder resin in the present invention means the molecular weight distribution measured by a molecular weight of 500 or more.

The content ratio of the component having a molecular weight of 500 to 100,000 is the molecular weight of 500 to 1 in the GPC chromatogram.
Cut out the part of 0,000, and weigh the part and the molecular weight of 10
It can be calculated by comparing the weights of ten or more cutout parts.

The content of the component having a molecular weight of 500,000 or more depends on the GP.
In the chromatogram of C, it can be determined by cutting out a region having a molecular weight of 500,000 or more, measuring the weight, and comparing it with the weights of other regions. In addition, molecular weight 5
It is also possible to obtain the area of more than 100,000 regions and compare it with the area of other regions.

Further, the magnetic toner of the present invention contains a magnetic material. Examples of the magnetic material contained in the magnetic toner of the present invention include iron oxides such as magnetite, γ-iron oxide ferrite, and iron-excessive ferrite; metals such as iron, cobalt, and nickel; or metals such as these, aluminum, cobalt, and copper. , Lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium,
Examples thereof include alloys with metals such as manganese, selenium, titanium, tungsten, and vanadium, and mixtures thereof.

These ferromagnetic materials have an average particle size of 0.1 to 1
μm, preferably about 0.1 to 0.5 μm. Resin component 1 should be included in the magnetic toner.
60 to 110 parts by weight with respect to 00 parts by weight, and preferably 65 to 100 parts by weight with respect to 100 parts by weight of the resin component.

In the magnetic toner of the present invention, it is preferable to use a charge control agent in the toner particles (internal addition) or mixed with the toner particles (external addition). Depending on the charge control agent,
It is possible to control the optimum charge amount according to the developing system, and particularly in the present invention, it is possible to further stabilize the balance between the binder resin and the charge. Examples of the positive charge control agent include modified products of nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate; dibutyltin oxide, dioctyltin. Oxides, diorganotin oxides such as dicyclohexyltin oxide; diorganotinborates such as dibutyltin borate, dioctyltin borate, and dicyclohexyltin borate. These can be used alone or in combination of two or more. Among these, nigrosine-based charge control agents and charge control agents such as organic quaternary ammonium salts are particularly preferably used.

General formula

[0060]

Embedded image [In the formula, R ₁ represents H or CH ₃ , and R ₂ and R ₃ represent a substituted or unsubstituted alkyl group (preferably C _{1 to} C ₄ ). ] A homopolymer of a monomer represented by the following; or a copolymer with a polymerizable monomer such as styrene, acrylic acid ester, and methacrylic acid ester as described above can be used as a positive charge control agent. In this case, these charge control agents also function as (all or part of) the binder resin.

As the negative charge control agent that can be used in the present invention, for example, an organometallic complex and a chelate compound are effective. Acetylacetone metal complex, salicylic acid metal complex or salt is particularly preferable. Examples thereof include aluminum acetylacetonate, iron (II) acetylacetonate, chromium 3,5-ditert-butylsalicylate, and zinc 3,5-ditert-butylsalicylate. In particular, a salicylic acid-based metal complex (including a substituted monoalkyl group or a substituted dialkyl group) or a salicylic acid-based metal salt (including a substituted monoalkyl group and a substituted dialkyl group) is preferable.

The charge control agent (which does not function as a binder resin) described above is preferably used in the form of fine particles. In this case, the number average particle size of the charge control agent is
Specifically, it is preferably 4 μm or less (further, 3 μm or less).

When internally added to the toner, such a charge control agent is preferably used in an amount of 0.1 to 20 parts by weight (more preferably 0.2 to 10 parts by weight) per 100 parts by weight of the binder resin.

The magnetic toner according to the present invention may be internally or externally mixed with various additives, if necessary. As the colorant, conventionally known dyes and pigments can be used, and usually 0.5 to 20 parts by weight may be used with respect to 100 parts by weight of the binder resin. Other additives include, for example, lubricants such as zinc stearate; abrasives such as cerium oxide, silicon carbide and strontium titanate; fluidity-imparting agents or anti-caking agents such as colloidal silica and aluminum oxide; carbon black, for example.
There are conductivity-imparting agents such as tin oxide.

In order to produce the magnetic toner of the present invention, a binder resin containing magnetic iron oxide and polyolefin, and if necessary, a pigment or dye as a colorant, a charge control agent and other additives are added in a ball mill or the like. After thoroughly mixing with a mixer, use a heat kneader such as a heating roll, kneader, or extruder to melt, knead, and knead meat to disperse or dissolve the pigment or dye in the resin to make them compatible with each other. The magnetic toner according to the present invention can be obtained by crushing, cooling and solidifying, and then pulverizing and classifying.

Fine silica powder may be added internally or externally and mixed to the magnetic toner according to the present invention, but externally added and mixed is more preferable. When the magnetic toner particles are frictionally charged by bringing the magnetic toner particles into contact with the surface of a cylindrical conductive sleeve having a magnetic field generating means inside, when the number of contact between the toner particle surface and the sleeve increases, the toner particles wear Is likely to occur. When the magnetic toner of the present invention is combined with the silica fine powder, the silica fine powder is present between the toner particles and the surface of the sleeve, so that the wear is remarkably reduced.
As a result, the durability of the magnetic toner can be improved, and a developer having the magnetic toner that is more excellent in long-term use can be obtained.

As the silica fine powder, silica fine powder produced by a dry method or a wet method can be used, but it is preferable to use the silica fine powder by the dry method from the viewpoint of filming resistance and durability.

The dry method mentioned here is a method for producing fine silica powder produced by vapor phase oxidation of a silicon halogen compound. For example, in a method utilizing the thermal decomposition oxidation reaction of silicon tetrachloride gas in oxygen-hydrogen, the basic reaction formula is as follows.

SiCl ₄ + 2H ₂ + O ₂ → SiO ₂ + 4HCl In this manufacturing process, for example, by using another metal halogen compound such as aluminum chloride or titanium chloride together with a silicon halogen compound, a composite fine powder of silica and another metal oxide is obtained. It is possible to obtain the body, and it includes them.

Commercially available silica fine powders produced by vapor phase oxidation of a silicon halogen compound used in the present invention include, for example, those commercially available under the following trade names.

AEROSIL (Japan Aerosil Co., Ltd.) 130 200 300 380 OX50 TT600 MOX80 MOX170 COK84 Ca-O-SiL (CABOTO Co.) M-5 MS-7 MS-75 HS-5 EH-5 Wacker HDK N 20 V15 ( WACKER-CHEMIE GMBH) N20E T30 T40 DC Fine Silica (Dow Corning Co.) Francol (Fransil) The wet method for producing the silica fine powder used in the present invention is various conventionally known methods. Can be applied. For example, decomposition of sodium silicate represented by the following general reaction formula by an acid can be mentioned.

Na ₂ O · XSiO ₂ + HCl + H ₂ O → SiO ₂ · nH ₂ O + NaCl In addition, after decomposition of sodium silicate with ammonia salts or alkali salts, after generating an alkaline earth metal silicate from sodium silicate , A method of decomposing with acid to silicic acid, a method of converting a sodium silicate solution into silicic acid by an ion exchange resin, a method of utilizing natural silicic acid or a silicate, and the like.

As the silica fine powder referred to herein, anhydrous silicon dioxide (colloidal silica) and other silicates such as aluminum silicate, sodium silicate, potassium silicate, magnesium silicate and silicic acid can be applied.

Examples of commercially available silicic acid fine powders synthesized by the wet method include those commercially available under the following trade names. Carplex Shionogi NIPSEAL NIPPON SILICA TOKUSEAL, FINE SEAL Tokuyama Soda Vita-seal Takihi Shilton, Shirnex Mizusawa Chemical Stasir Kamijima Kagaku Himedir Ehime Pharmaceutical Syroid Fuji-Dil Chemical Hi-Sil (High Seal) Pittsburgh Plate Glass. Co (Pittsburgh Plate Glass) Durosil (Duro-Seal) Ultrasil (Ultra-Seal) Fillstoff-Gesellschaft Marquart (Furstoff Gesellschaft Marquardt) Manosil (Manosir) Hardman and Henmann Harden and Harden G (Hemische Fabry Heche) Sil-Stone Stoner Rubber Co. (Stoner rubber) Nalco Nalco Chem. Co. (Narco Chemical) Quoso (Philadelphia Quartz Co.) (Philadelphia Quartz) Imsil Illinois Minerals Co. (Illinois Minerals) Calcium Silikat Chemische Fabrik Hoesch. KG (Hemische Fabryg Hech) Calsil (Calzil) Fillstoff-Gesellschaft Marquart (Furstoff-Geselleschaft Marquardt) Fortafil (Fortafil) Imperial Chemical Industries. Ltd. (Imperial Chemical Industries) Microcal Joseph Crossfields & Sons. Ltd. (Joseph Crossfield and Sons) Manosil (Manosir) Hardman and Holden (Hardman and Holden) Vulkasil (Burkazir) Farbenfabriken Brier, A. -G. (Farben Fabry Ken Bayer) Tufknit (Tough Knit) Durham Chemicals. Ltd. (Durham Chemicals) Silmos Shiraishi Kogyo Starrex Kamishima Kagaku Fricosil Polywood Manure Of the above silica fine powder, the specific surface area by nitrogen adsorption measured by the BET method is 30 m ² / g or more (particularly 50 to 400 m ² / g) The ones inside give good results. Silica fine powder 0.
It is preferable to use 01 to 8 parts by weight, preferably 0.1 to 5 parts by weight.

When the magnetic toner according to the present invention is used as a positively chargeable magnetic toner, it is preferable to use positively chargeable silica fine powder as the silica fine powder to be added, rather than negatively chargeable silica. It is preferable because it does not impair.

As the method for obtaining finely charged silica fine powder, the above-mentioned untreated silica fine powder is treated with a silicone oil having an organo group having at least one nitrogen atom in its side chain, or a nitrogen-containing silica powder. There is a method of treating with the above silane coupling agent, or a method of treating with both of them.

In the present invention, the positively chargeable silica is one having a positive triboelectric charge with respect to the iron powder carrier when measured by the blow-off method.

As the silicone oil having a nitrogen atom in the side chain used for treating the silica fine powder, a silicone oil having at least a partial structure represented by the following formula can be used.

[0079]

Embedded image (In the formula, R ₁ represents hydrogen, an alkyl group, an aryl group or an alkoxy group, R ₂ represents an alkylene group or a phenylene group, R ₃ and R ₄ represent hydrogen, an alkyl group or an aryl group, and R ₅ Represents a nitrogen-containing heterocyclic group) In the above formula, the alkyl group, the aryl group, the alkylene group and the phenylene group may have an organo group having a nitrogen atom, and within a range not impairing the charging property, such as halogen. It may have a substituent.

The nitrogen-containing silane coupling agent used in the present invention generally has a structure represented by the following formula.

R _m —Si—Y _n (R represents an alkoxy group or halogen, Y represents an amino group or an organo group having at least one nitrogen atom, and m and n are integers of 1 to 3. M +
n = 4. Examples of the organo group having at least one nitrogen atom include an amino group having an organic group as a substituent, a nitrogen-containing heterocyclic group, or a group having a nitrogen-containing heterocyclic group. As the nitrogen-containing heterocyclic group, there is an unsaturated heterocyclic group or a saturated heterocyclic group, and known ones can be applied. Examples of the unsaturated heterocyclic group include the following.

[0082]

Embedded image Examples of the saturated heterocyclic group include the following.

[0083]

Embedded image The heterocyclic group used in the present invention is preferably a 5- or 6-membered ring in consideration of stability.

Examples of such treating agents include aminopropyltrimethoxysilane, aminopropyltriethoxysilane, dimethylaminopropyltrimethoxysilane,
Diethylaminopropyltriethoxysilane, dipropylaminopropyltrimethoxysilane, dibutylaminopropyldimethoxysilane, monobutylaminopropyltriethoxysilane, dioctylaminopropyltriethoxysilane, dibutylaminopropyltrimethoxysilane, dibutylaminopropylmonomethoxysilane, dimethyl There are aminophenyltriethoxysilane, trimethoxysilyl-γ-propylphenylamine, trimethoxysilyl-γ-propylbenzylamine, and further, as the nitrogen-containing heterocyclic group, those having the above structure can be used,
Examples of such compounds include trimethoxysilyl-
There are γ-propylpiperidine, trimethoxysilyl-γ-propylmorpholine, and trimethoxysilyl-γ-propylimidazole.

The amount of the treated positively charged silica fine powder applied is 0.01 to 8 parts by weight based on 100 parts by weight of the positively charged magnetic toner, and particularly preferably 0. When added in an amount of 1 to 5 parts by weight, it exhibits a positive chargeability with excellent stability. A preferable mode of addition is as follows: 0.1 to 3 parts by weight of the treated silica fine powder adheres to the toner particle surface with respect to 100 parts by weight of the positively chargeable magnetic toner. good. The untreated fine silica powder described above can be used in the same application amount.

The silica fine powder used in the present invention may be treated with a silane coupling agent or a treating agent such as an organic silicon compound for the purpose of hydrophobizing, if necessary, and it reacts with the silica fine powder or is physically adsorbed. Is treated with the above-mentioned treating agent. Examples of such a treating agent include hexamethylsilane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, and bromine. Methyldimethylchlorosilane,
α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganoserialylate, vinyldimethylacetoxysilane, dimethylethoxysilane,
Dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane, and 2 to 12 siloxane units per molecule, terminal There is a dimethylpolysiloxane containing a hydroxyl group bonded to Si for each one unit located at. These are used alone or in a mixture of two or more.

In the magnetic toner of the present invention, fine powder of a fluorine-containing polymer may be added internally or externally. Examples of the fluorine-containing polymer fine powder include fine powders of polytetrafluoroethylene, polyvinylidene fluoride, and a tetrafluoroethylene-vinylidene fluoride copolymer. Particularly, fine powder of polyvinylidene fluoride is preferable in terms of fluidity and abrasivity. The amount added to the toner is 0.01 to 2.0% by weight, especially 0.02
To 1.0% by weight is preferable.

In particular, for the magnetic toner in which the fine silica powder and the fine powder are externally added and mixed, the reason why the presence of the silica adhering to the toner is stabilized and the adhering silica is released from the toner, although the reason is not clear. As a result, the effects of toner abrasion and sleeve contamination are not reduced, and the charging stability can be further increased.

An example of a specific apparatus that can be used for carrying out the image forming process in the present invention will be described with reference to FIGS. 1 and 2 which is a partially enlarged view of FIG.

Reference numeral 2 denotes a corona charger as a charging means for the photosensitive drum 1, which charges the photosensitive drum to a negative polarity and forms an electrostatic latent image by exposure. The latent image is developed with, for example, the positively chargeable magnetic toner 10 of the present invention in a developing device 9 having a non-magnetic developing sleeve 4 as a developer carrying body containing a magnetic blade 11 made of iron and a magnet 40.
The developing sleeve 4 is a stainless steel sleeve (SUS30) sandblasted with # 400 carborundum.
4) is used. In the developing section, the bias applying means 1 is provided between the conductive substrate of the photosensitive drum and the developing sleeve 4.
Alternate bias, pulse bias and / or DC bias are applied by 2. When the transfer sheet P is conveyed and reaches the transfer section, the rear surface of the transfer sheet P is charged by the corona charger 3 having the voltage applying means 14, so that a developed image (toner image) on the surface of the photosensitive drum 1 is formed. It is electrostatically transferred onto the transfer paper P. Transfer paper P separated from the photosensitive drum 1
The toner image on the transfer paper P is fixed by the heat and pressure roller fixing device 7.

The magnetic toner remaining on the photosensitive drum 1 after the transfer process is removed by a cleaning device 8 having a cleaning blade. After the cleaning, the photosensitive drum 1 is neutralized by the erase exposure 6, and the process starting from the charging process by the charger 2 is repeated again.

[0092]

Although the basic structure and features of the present invention have been described above, the present invention will be specifically described below with reference to examples.
However, this does not limit the invention in any way. Parts in the following formulations are parts by weight.

Example 1 200 parts of ion-exchanged water, 80 parts of styrene, 20 parts of n-butyl acrylate, 1,4 as a polymerization initiator were placed in a four-necked flask equipped with a nitrogen gas introduction tube, a condenser, a stirrer and a thermometer. -Bis (t-butylperoxycarbonyl)
0.4 parts of cyclohexane (HTP) was added and the polymerization temperature was 9
Suspension polymerization was carried out at 0 ° C for 24 hours. Then, it was cooled, washed with water and dried to obtain a high molecular weight polymer (resin P). 100 parts of this high molecular weight polymer was added to 1000 parts of methyl ethyl ketone.
Part, then, ethanol was added dropwise to this solution until 95% by weight of the high molecular weight polymer component was precipitated, and the precipitated high molecular weight polymer component was washed with water and dried to obtain a binder resin component I. It was The molecular weight distribution of this binder resin component I is
When measured by C, as shown in Table 1, it had a peak (P2) at a molecular weight of 630,000, and the ratio of components having a molecular weight of 500 to 100,000 was 12.1%.

Next, xylene 80 was placed in a four-necked flask equipped with a nitrogen gas introduction tube, a condenser, a stirrer, and a thermometer.
0 parts was added, and the temperature was raised with stirring under a nitrogen gas stream and maintained at 90 ° C., 83 parts of styrene, 17 parts of n-butyl acrylate,
Di-t-butyl peroxide (DT) as a polymerization initiator
A mixture of 4.3 parts of (BP) was added dropwise using a continuous dropping device over 6 hours to carry out solution polymerization to obtain a solution in which a binder resin component B which is a low molecular weight polymer was dissolved. When the molecular weight distribution of the binder resin component B was measured by GPC, it had a peak (P1) at a molecular weight of 12,000 as shown in Table 1, and M
It was w / Mn = 1.95.

The above solution (containing 60 parts of binder resin component B)
Binder resin component I: 40 parts, low molecular weight polypropylene (weight average molecular weight = about 10000): 4 parts were added thereto, and the mixture was dissolved and mixed at a temperature of 100 ° C for about 4 hours with sufficient stirring, and then xylene. Was removed to obtain a final binder resin for toner.

With respect to 100 parts of the above binder resin for toner,
The following materials were mixed well with a blender. -Triiron tetraoxide (average particle size: 0.2 μm): 80 parts-Nigrosine: 2 parts Then, the mixture was kneaded with a twin-screw kneading extruder set at 80 ° C. The obtained kneaded product is cooled, coarsely pulverized by a cutter mill, then finely pulverized by a fine pulverizer using a jet stream, and the finely pulverized powder obtained is divided by a multi-division classifier utilizing the Coanda effect. And classified to obtain positively charged magnetic black fine powder (magnetic toner) having a volume average particle diameter of 8.5 μm.

100 parts of the obtained magnetic toner was added to positively charged hydrophobic dry silica fine powder (BET specific surface area: 200 m ²
/ G) 0.6 part, and 0.1 part of polyvinylidene fluoride fine powder are added and mixed with a Henschel mixer,
A positively chargeable insulating magnetic toner having silica particles in the magnetic toner particles v / was used.

The molecular weight distribution of the above binder resin for magnetic toner measured by GPC under the following measurement conditions is shown in FIG.

-GPC measurement condition apparatus LC-GPC 150C (Waters Co.) column Shodex KF-801, 802, 803, 804, 805, 806 and 807, KF-800P (Showa Denko KK) temperature 40 ° C solvent tetrahydrofuran ( THF) flow rate 1.0 ml / min sample 0.1 ml of sample having a sample concentration of 3 to 7 mg / ml was injected. As a result, the maximum value of P1max was located at a molecular weight of 12,000, and the maximum value of P3max was at a molecular weight of 630,000. The ratio of the height H1 of the maximum peak P1max on the low molecular weight region side to the height H3 of the maximum peak P3max on the high molecular weight region side to the height H2 of the minimum value V2min between both peaks is H1:
H2: H3 = 9.5: 1: 4.5 and Mw / Mn =
It was 28.0.

The above magnetic toner was put into a developing device of a modified machine in which the fixing device of the electrophotographic copying machine NP4835 (manufactured by Canon Inc.) was removed, and an unfixed image was obtained. On the other hand, the fixing device detached from the copying machine NP4835 was modified to be a temperature-variable heat-pressure roller external fixing device, and using this, a fixing test of an unfixed image and an offset test were conducted.

The nip width of the external fixing device is set to 4.0 mm, the process speed is set to 150 mm / s, and the temperature is set to 100 ° C to 2 ° C.
The unfixed image is fixed at each temperature by controlling the temperature in the temperature range of 40 ° C. at intervals of 5 ° C.
was rubbed with lens-cleaning paper applying a load of cm ^2, and the fixing temperature rubbing before and image density decrease rate after rubbing is 2% or less and the fixing initiation temperature. As a result, the fixing start temperature is 160 ° C.
It was low and excellent in low-temperature fixability. The offset start temperature was as high as 240 ° C. or higher, and the offset resistance was excellent. Further, an image forming test was conducted using an electrophotographic copying machine NP3725 (manufactured by Canon Inc.) having a developing sleeve blasted with irregular particles, and the state of contamination on the surface of the developing sleeve was observed. Image drawing test 50
A durability test was also performed continuously for 00 times. Initial image and 5
The image density Dmax was high in all 000-sheet durable images, and the images were clear and of high image quality without fog, and no toner contamination was found on the surface of the developing sleeve.

The magnetic toner was allowed to stand in a dryer at 50 ° C. for 2 weeks to test the blocking resistance of the toner, but there was no problem at all.

Further, when the obtained toner was observed with a polarizing microscope, the release agent was uniformly dispersed in the toner particles, and no release agent released between the toner particles was found at all.

The results are shown in Tables 2 and 3.

Comparative Example 1 Magnetic properties were the same as in Example 1 except that 90 parts of the binder resin component B was mixed as the low molecular weight polymer component and 10 parts of the binder resin component I was mixed as the high molecular weight polymer component. A toner was prepared and evaluated.

Comparative Example 2 Example 1 was repeated except that only 100 parts of the binder resin component B which was a low molecular weight polymer component was used as the binder resin for toner.
In the same manner as above, a magnetic toner was prepared and evaluated.

The results of Comparative Examples 1 and 2 are shown in Tables 2 and 3. When compared with Example 1, both Comparative Examples were able to obtain the same or higher performance in terms of fixing property, but were significantly inferior in offset start temperature, and could not be preferably used practically. Initial and 5000
The image quality after sheet durability and the blocking resistance were also inferior to those of Example 1 in both comparative examples. Comparative Example 1 was slightly better than Comparative Example 2. It is considered that this is because the dispersibility of the release agent was improved by adding the high molecular weight polymer component. For this confirmation, when the toners of Comparative Examples 1 and 2 were observed with a polarization microscope, the presence of more released release agent particles than that of Comparative Example 1 was observed between the toner particles of Comparative Example 2.

Comparative Example 3 As shown in Table 1, a resin P used for preparing a binder resin component I as a high molecular weight polymer component by a fractional precipitation method.
A magnetic toner was prepared and evaluated in the same manner as in Example 1 except that itself was used. The results are shown in Tables 2 and 3. The fixing start temperature was increased to 170 ° C. and the offset start temperature was decreased to 220 ° C. as compared with the above-described Example 1. It is considered that this is because, since the fractional precipitation method was not used, the components in the intermediate molecular weight region, which did not contribute to fixing and offset resistance, increased, which caused deterioration of fixing property and offset property. There were no problems regarding image characteristics and blocking resistance.

Then, the type of polymerization initiator, the amount used, the type of solvent, the polymerization temperature, etc. were changed and the same procedure as in Example 1 was conducted.
Shown in Polymers A, CtoH and JtoO composed of styrene-n-butyl acrylate copolymer were prepared and used in the following Comparative Examples and Examples.

Comparative Example 4 As shown in Table 1, as a high molecular weight polymer component, BPO (benzoyl peroxide) 0.4 was used as a polymerization initiator.
A binder resin was produced in the same manner as in Example 1 except that the resin O obtained by using the parts was used as it was without performing the fractional precipitation method. Then, a magnetic toner was prepared and evaluated.
The molecular weight distribution of GPC of the binder resin measured in the same manner as in Example 1 is shown in FIG. As a result of the evaluation, as shown in Tables 2 and 3, some fog was recognized from the initial image, and
In the post-durability image after printing 0 sheets, severe fog was recognized on the image. Regarding the fixability, the fixing start temperature is 17
The fixing start temperature was as high as 0 ° C., and the low-temperature fixability was not excellent. As a result of the offset test, the offset start temperature was 200 ° C., which was worse than that of Example 1. Further, in the evaluation of blocking resistance, the aggregation of the toner was more severe than that in Example 1 described above. This is because the position of the maximum value of P3max on the polymer side is extremely small,
It is considered that the dispersibility of the release agent deteriorated and that it was caused as a result.

Example 2 A magnetic toner was prepared and evaluated in the same manner as in Example 1 except that the solution of the low molecular weight polymer containing the binder resin component D was used.

Example 3 A magnetic toner was prepared and evaluated in the same manner as in Example 1 except that the solution of the low molecular weight polymer containing the binder resin component E was used.

The results of Examples 2 and 3 are shown in Tables 2 and 3. Compared with Example 1, offset start temperature, blocking resistance, and image characteristics after enduring 5,000 sheets in Example 2 were slightly lower than fixing start temperature in Example 3, but good results were obtained. Was given.

Comparative Example 5 A magnetic toner was prepared and evaluated in the same manner as in Example 1 except that a low molecular weight polymer solution containing the binder resin component F was used.

Comparative Example 6 A magnetic toner was prepared and evaluated in the same manner as in Example 1 except that the solution of the low molecular weight polymer containing the binder resin component G was used.

The results of Comparative Examples 5 and 6 are shown in Tables 2 and 3. When compared with Example 1, the offset start temperature in Comparative Example 5 was significantly reduced in image characteristics after 5000 sheets of durability and blocking resistance, and in Comparative Example 6, the fixability was significantly decreased. In Example 3, the fixing start temperature was slightly lowered, but good results were obtained.

Example 4 except that Binder Resin K is used as the high molecular weight polymer component
A magnetic toner was prepared and evaluated in the same manner as in Example 1.

Example 5 Except that the binder resin L was used as the high molecular weight polymer component,
A magnetic toner was prepared and evaluated in the same manner as in Example 1.

The results of Examples 4 and 5 are shown in Tables 2 and 3. When compared with Example 1, a slight decrease was observed in the offset start temperature in Example 4 and in the fixing start temperature in Example 5, but it was not a problem. Other properties were good as in Example 1.

Comparative Example 7 Except that a binder resin M was used as the high molecular weight polymer component,
A magnetic toner was prepared and evaluated in the same manner as in Example 1.

Comparative Example 8 Except that the binder resin N was used as the high molecular weight polymer component,
A magnetic toner was prepared and evaluated in the same manner as in Example 1.

The results of Comparative Examples 7 and 8 are shown in Tables 2 and 3. When compared to Example 1, Comparative Example 7 was significantly inferior in offset start temperature and blocking resistance, and Comparative Example 8 was significantly inferior in fixing property.

Example 6 A solution containing a resin C as a low molecular weight polymer component and a binder resin H used as a high molecular weight polymer component were used. A magnetic toner was prepared and evaluated in the same manner as in Example 1 except that the components were mixed so as to form parts.

Example 7 A solution containing a binder resin A as a low molecular weight polymer component and a binder resin I as a high molecular weight polymer component were prepared by combining resin A and resin I as a binder resin component. 70 copies and 3 respectively
A magnetic toner was prepared and evaluated in the same manner as in Example 1 except that the mixing was carried out so that the content was 0 part.

The results of Examples 6 and 7 are shown in Tables 2 and 3. When compared with Example 1, the fixing start temperature in Example 6 and the offset start temperature in Example 7 and the image characteristics after 5000 sheets endurance and blocking resistance were slightly lowered, but the results were good. It was Other properties were good as in Example 1.

Comparative Example 9 A solution containing a binder resin E as a low molecular weight polymer component and a binder resin H as a high molecular weight polymer component were prepared by combining resin E and resin H as a binder resin component. 35 copies and 6 respectively
A magnetic toner was prepared and evaluated in the same manner as in Example 1 except that 5 parts were mixed.

COMPARATIVE EXAMPLE 10 A solution containing a binder resin D as a low molecular weight polymer component and a binder resin L as a high molecular weight polymer component were mixed with resin D and resin L as a binder resin component. 65 copies and 3 respectively
A magnetic toner was prepared and evaluated in the same manner as in Example 1 except that 5 parts were mixed.

The results of Comparative Examples 9 and 10 are shown in Tables 2 and 3. When compared with Example 1, a significant deterioration was observed in the fixability in Comparative Example 9, and in the offset start temperature, the image characteristics at the initial stage and after 5000 sheets endurance, and the blocking resistance in Comparative Example 10.

Example 8 A solution containing a binder resin B as a low-molecular weight polymer component and a binder resin H as a high-molecular weight polymer component were mixed with each other by using a resin B and a resin H as binder resin components. 65 copies and 3 respectively
A magnetic toner was prepared and evaluated in the same manner as in Example 1 except that 5 parts were mixed.

Example 9 A solution containing a binder resin A as a low molecular weight polymer component and a binder resin J as a high molecular weight polymer component were prepared by combining resin A and resin J as a binder resin component. 35 copies and 6 respectively
A magnetic toner was prepared and evaluated in the same manner as in Example 1 except that 5 parts were mixed.

The results of Examples 8 and 9 are shown in Tables 2 and 3. When compared with Example 1, the offset start temperature in Example 8 was good, but the image characteristics and blocking resistance after enduring 5000 sheets were good, while the fixing start temperature in Example 9 was slightly lowered. . Other characteristics are
It was equivalent to Example 1.

Comparative Example 11 A solution containing a binder resin A as a low molecular weight polymer component and a binder resin K which is a high molecular weight polymer component were prepared by combining a resin A and a resin K as binder resin components. 70 copies and 3 respectively
A magnetic toner was prepared and evaluated in the same manner as in Example 1 except that the mixing was carried out so that the content was 0 part.

Comparative Example 12 A solution containing a binder resin A as a low molecular weight polymer component and a binder resin as a high molecular weight polymer component, and a resin A and a resin as binder resin components were 30 and 30 respectively. A magnetic toner was prepared and evaluated in the same manner as in Example 1 except that the mixing ratio was adjusted to 70 parts.

The results of Comparative Examples 11 and 12 are shown in Tables 2 and 3.
Shown in When compared to Example 1, the offset start temperature, the image characteristics at the initial stage and after 5000 sheets of endurance, and the blocking resistance were significantly reduced in Comparative Example 11, and the fixability was significantly reduced in Comparative Example 12.

Example 10 A solution containing a binder resin E as a low molecular weight polymer component and a binder resin H as a high molecular weight polymer component were mixed with each other by using a resin E and a resin H as binder resin components. 70 copies and 3 respectively
A magnetic toner was prepared and evaluated in the same manner as in Example 1 except that the mixing was carried out so that the content was 0 part.

Example 11 A solution containing a binder resin E as a low molecular weight polymer component and a binder resin L as a high molecular weight polymer component were prepared by combining a resin E and a resin L as binder resin components. 35 copies and 6 respectively
A magnetic toner was prepared and evaluated in the same manner as in Example 1 except that 5 parts were mixed.

The results of Examples 10 and 11 are shown in Tables 2 and 3.
Shown in When compared with Example 1, in Example 10, the offset start temperature, the image characteristics after 5,000 sheets endurance,
The blocking resistance was still good in Example 11, although the fixing start temperature was slightly lowered. The other characteristics were the same as in Example 1.

Comparative Example 13 A solution containing a binder resin E as a low molecular weight polymer component and a binder resin K as a high molecular weight polymer component were prepared by combining resin E and resin K as a binder resin component. 75 copies and 2 respectively
A magnetic toner was prepared and evaluated in the same manner as in Example 1 except that 5 parts were mixed.

Comparative Example 14 A solution containing a binder resin B as a low-molecular weight polymer component and a binder resin L as a high-molecular weight polymer component were mixed with resin B and resin L as a binder resin component. 25 copies and 7 respectively
A magnetic toner was prepared and evaluated in the same manner as in Example 1 except that 5 parts were mixed.

The results of Comparative Examples 13 and 14 are shown in Tables 2 and 3.
Shown in When compared with Example 1, the offset start temperature, the image characteristics at the initial stage and after the 5000-sheet endurance, and the blocking resistance in Comparative Example 13 were significantly inferior in the fixing property in Comparative Example 14.

Comparative Example 15 The same as Example 1 except that low-molecular-weight polypropylene was not previously dispersed and contained in the binder resin, but was added in the raw material rough mixing process like iron trioxide and nigrosine. Then, a magnetic toner was prepared and evaluated. Compared with Example 1, the image characteristics (fogging), offset resistance, and blocking resistance were slightly inferior. To find out why blocking resistance is slightly inferior,
Observation of the untreated toner with a polarizing microscope revealed that many free release agent particles were present among the toner particles. It is considered that the particles of the released release agent slightly deteriorated the blocking resistance as compared with Example 1.

[0142]

[Table 1]

[0143]

[Table 2]

[0144]

[Table 3]

Comparative Example 16 A high molecular weight polymer Q was synthesized in the same manner as the resin P in Example 1 using benzoyl peroxide as a polymerization initiator. The obtained high molecular weight polymer Q has a peak value (P2) of 220,000, a content of a component in the molecular weight range of 500 to 100,000 is 32%, and a content of a component in the molecular weight range of 500,000 or more. Is 11% and Mw / Mn is 1.7.
Met.

Next, a low molecular weight polymer R was synthesized in the same manner as the resin B in Example 1 using benzoyl peroxide as a polymerization initiator. The obtained low molecular weight polymer has a peak value (P1) of 12,000 and Mw /
Mn was 2.00, and the component in the region having a molecular weight of 500,000 or more was not substantially contained.

66 parts by weight of the low molecular weight polymer R, 34 parts by weight of the high molecular weight polymer and 4 parts by weight of the low molecular weight polypropylene were added to 300 parts by weight of xylene and mixed while heating at a temperature of 100 ° C. Then, xylene was removed to prepare a binder resin.

The obtained binder resin had a P1max of 1.2.
10,000, P3max is 220,000, H1: H2: H
3 was 9.5: 1: 1.2, Mw / Mn was 21, and the content of the component in the region where the molecular weight was 500,000 or more was 3%.

Using the obtained binder resin, a magnetic toner was prepared in the same manner as in Example 1, and an image development test was conducted in the same manner as in Example 1 to evaluate. However, the offset start temperature was 200 ° C., which was lower than that in Example 1, and the temperature range in which good heat and pressure fixing could be performed was narrow.

[0150]

The magnetic toner of the present invention is excellent in low-temperature fixing performance against heat roll fixing and, at the same time, can maintain offset resistance.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram for explaining an image forming process in which a magnetic toner of the present invention can be used.

FIG. 2 is a partially enlarged view of FIG. 1 for explaining a developing process.

3 is a molecular weight distribution of the binder resin of the magnetic toner of Example 1 measured by GPC. FIG.

FIG. 4 is a molecular weight distribution measured by GPC of a binder resin of a magnetic toner of Comparative Example 4.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrostatic image carrier 2 Charging means 3 Transfer means 7 Fixing means 9 Developing means 10 Magnetic toner

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kuniko Kobayashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masami Fujimoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Kazuyoshi Hagiwara 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) Reference JP 4-24649 (JP, A) JP 2-3111851 (JP) , A) JP 2-12160 (JP, A) JP 63-17461 (JP, A)

Claims (7)

(57) [Claims] 1. A binder resin containing at least a styrene polymer or a styrene copolymer, and a polyolefin or a binder resin .
Others wax, magnetic toner der containing a magnetic substance
Before the binder resin and magnetic substance are mixed,
Or wax Yes is previously dispersed in a binder resin, said binder resin is a non-crosslinked polymer, the chromatogram measured by GPC (gel permeation chromatography) using tetrahydrofuran for binding Chakujushi and solvent, It has at least one maximum in each of the molecular weight range of 5,000 to 20,000 and 200,000 to 1,000,000, and has the maximum peak height (H1) on the low molecular weight region side and the maximum peak height on the high molecular weight region side. Sa (H3)
And the minimum height (H2) between the two peaks is H1: H
2: H3 = 3 to 25: 1: 1.5 to 12 are satisfied, and the weight average molecular weight (Mw) and the number average molecular weight (Mn) are satisfied.
DOO is, the magnetic toner, wherein the Ru Mw / Mn = 15 to 80 der. 2. The polyolefin has a weight average molecular weight of 2
The magnetic toner according to claim 1, which is 000 to 30,000.
- 3. The polyolefin or wax is a solvent.
Dissolved with the binder resin and then the solvent can be removed.
The dispersion according to claim 1 or 2 dispersed in the binder resin by
The magnetic toner described. 4. A low molecular weight polymer (a), a high molecular weight polymer (b)
Coalesced, (c) polyolefin or wax and (d)
Mixing with a solvent, the low molecular weight polymer, high molecular weight in the solvent
Dissolve polymer and polyolefin or wax
To prepare a mixture The solvent is removed from the mixture to remove the polyolefin or wax.
To produce a binder resin in which Binder with dispersed polyolefin or wax
Kneading fat and magnetic material, Cool the kneaded material, Crush the cooled kneaded product, Classify the crushed material, At least styrene-based polymer or styrene-based copolymer
Binder resin with polyolefin and polyolefin or wax
And a magnetic substance, and the binder resin
Is a non-crosslinked polymer, and the binder resin is tetrahydrofuran.
GPC (gel permeation chromatography)
Chromatogram measured by Rafi) shows the molecular weight
Areas of 5000 to 20,000 and 200,000 to 1 million
Each has at least one local maximum and low molecular weight region
Side maximum peak height (H1) and maximum high molecular weight region side
Peak height (H3) and minimum height between both peaks
(H2) is H1: H2: H3 = 3 to 25: 1: 1.5
And the weight average molecular weight (Mw) is satisfied.
The number average molecular weight (Mn) is Mw / Mn = 15 to 80
A method for producing a magnetic toner characterized by the following. 5. The high molecular weight polymer has a molecular weight of 500 to 1
The component of the range of 0,000 is 30% by weight or less.
Method for manufacturing magnetic toner described above. 6. The low molecular weight polymer is a styrenic copolymer.
Yes, claim that the high molecular weight polymer is a styrenic copolymer
Item 6. A method for producing a magnetic toner according to Item 4 or 5. 7. The polyolefin has a weight average molecular weight of 20.
It is 00-30000, It describes in any one of Claims 4 thru | or 6.
Method for manufacturing magnetic toner described above.