JP3404463B2 - Magnetic one-component developer and developing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic one-component developer used in electrophotography and a developing method therefor,
Specifically, improvement in image density of a magnetic one-component developing agent for jumping development to prevent or reduce the occurrence of memory phenomenon and its development method.

[0002]

2. Description of the Related Art Generally, electrophotography is a method in which a latent image is electrically formed on a photoconductor, the latent image is developed with a toner, and the toner image is transferred to a transfer material such as paper as required. After that, the toner image is fixed on the transfer material by means such as heating and pressing to obtain a copy. Developers used in such an electrophotographic method include a two-component developer including a toner component and a carrier component, and a one-component developer having both the functions of the toner and the carrier.

The two-component developer is excellent in electrophotographic characteristics such as transferability, fixability and environmental resistance. However, since it is necessary to control the mixing ratio of the toner component and the carrier component, a toner concentration sensor is required in the developing device, and a stirring mechanism for stirring the toner component and the carrier component is required. It had problems such as becoming complicated and complicated. Further, the two-component developer is prone to deterioration and has a problem that the life is short.

In recent years, a developing method using a magnetic one-component developer has been proposed and put into practical use in order to make the developing device compact and simple and to achieve both electrophotographic characteristics. To develop a magnetic one-component developer, the magnetic one-component developer is carried by contacting the magnetic one-component developer carried on a non-magnetic sleeve with a photoreceptor carrying an electrostatic latent image. A contact type magnetic one-component developing method in which the image is transferred to the image for development and a non-magnetic sleeve carrying the magnetic one-component developer and the photoconductor holding the electrostatic latent image have a constant gap (gap). ) Is provided, and the magnetic one-component developer is transferred (jumping) to the electrostatic latent image in a non-contact manner to develop the non-contact type magnetic one-component developing method.

In the contact type magnetic one-component developing method, since the magnetic one-component developer on the non-magnetic sleeve and the photosensitive member are in contact with each other, the developability is good. However, the magnetic one-component developer receives not only friction when it is agitated in the developing device, but also friction caused by contact with the photoconductor, so that the mechanical load on the magnetic one-component developer increases. there were.

FIG. 1 is a schematic view of an apparatus used in a non-contact type magnetic one-component developing method. This developing device includes a cylindrical photosensitive drum 1 which is an electrostatic latent image holder, a hopper 2 in which a magnetic one-component developer 3 is stored, and a photosensitive drum 1.
And a non-magnetic sleeve 6 made of aluminum whose right half peripheral surface is housed in the hopper 2 and whose left half peripheral surface faces the photoconductor drum 1, and a non-magnetic sleeve 6 incorporated therein. The magnetized roller 5 and the magnetic blade 4 that makes the layer of the magnetic one-component developer 3 carried on the non-magnetic sleeve 6 uniform in thickness and the magnetic one-component developer 3 in the hopper 2 are agitated. The stirrer 7, the non-magnetic sleeve 6 and the magnetic blade 4 are kept electrically connected,
The photoconductor drum 1 has a power supply 8 for applying an alternating bias voltage and a DC bias voltage.

The non-contact type magnetic one-component developing method using this apparatus is carried out as follows. First, an electrostatic latent image is formed on the surface of the photosensitive drum 1 by a known electrophotographic method. On the other hand, the magnetic one-component developer 3 in the hopper 2 is
The magnetic blade 4 is carried on the surface of the non-magnetic sleeve 6 containing the magnet roller 5 so as to have a constant layer thickness, and is conveyed. By applying an alternating bias voltage and a DC bias voltage from the power source 8 to the photoconductor drum 1, a DC electric field and an AC electric field are generated between the nonmagnetic sleeve 6 and the photoconductor drum 1, and the nonmagnetic sleeve 6 has a surface. The magnetic one-component developer 3 is jumped and developed into an electrostatic latent image on the surface of the photosensitive drum 1.

In the non-contact type magnetic one-component developing method using this developing device, since the magnetic one-component developer 3 is frictionally charged only by the magnetic blade 4, the magnetic one-component developer 3 is used.
The mechanical load on the However, in the case of the non-contact type, the developability is generally inferior to that of the contact type because a gap is present during development. In particular, when the magnetic toner contained in the magnetic one-component developer 3 has a small particle diameter of several μm, it is difficult to obtain good developability.

In the non-contact type magnetic one-component developing method,
As one of the means for improving the developability, it can be considered to increase the supply amount of the magnetic one-component developer 3 to the non-magnetic sleeve 6. In particular, when a magnetic toner having a small particle diameter of several μm is used, it is an important issue to secure a sufficient transport amount of the magnetic one-component developer 3. As a method of solving this problem, it has been considered to increase the amount of the magnetic one-component developer 3 passing through by widening the gap between the non-magnetic sleeve 6 and the magnetic blade 4 in the developing device.

However, when the passing amount of the magnetic one-component developer 3 is increased as described above, the charge injection into the magnetic one-component developer 3 by the magnetic blade 4 is not sufficiently performed,
The triboelectric charging of the magnetic one-component developer 3 becomes insufficient, and the thin layer of the magnetic one-component developer 3 on the surface of the non-magnetic sleeve 6 becomes uneven. Therefore, when a document such as black solid or halftone is developed in a state where the thin layer of the magnetic one-component developer 3 is not uniform, there is a problem that the image is blurred. In particular, when developing by rotating the non-magnetic sleeve 6 twice or more, the magnetic one-component developer 3 remaining on the surface of the non-magnetic sleeve 4 without being completely transferred to the photosensitive drum 1 during the first rotation There has been a serious problem that a phenomenon that an afterimage appears at the time of the second rotation development, that is, a memory phenomenon occurs.

[0011]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to obtain a uniform thin layer on a non-magnetic sleeve, and to increase the image density and to reduce image blur even when a magnetic toner having a small particle size is used. It is an object of the present invention to provide a magnetic one-component developer capable of reducing the occurrence of a memory phenomenon and a memory phenomenon and obtaining sufficient developability, and a developing method thereof.

[0012]

That is, the magnetic one-component developer of the present invention contains a magnetic toner containing a binder resin and a magnetic substance, a thermosetting resin and a magnetic substance, and has a volume average particle diameter. Is 1 to 15 % by weight of the composite spherical particles having a diameter of 5 μm or more and less than 15 μm . Also,
The magnetic one-component developer of the present invention contains a binder resin and a magnetic material.
Contains magnetic toner, thermosetting resin and magnetic material
And the volume average particle size is 15 μm or more and less than 35 μm
Magnetic composition with certain composite spherical particles 5 to 50% by weight
It is a developer and the content of the magnetic substance in the magnetic toner is 6
5 wt% or less, inclusion of magnetic material in the composite spherical particles
The amount is 85-95% by weight . Also,
The magnetic one-component developer of the present invention contains a binder resin and a magnetic material.
Contains magnetic toner, thermosetting resin and magnetic material
And having a volume average particle diameter of 35 to 100 μm
1 to 5% by weight of spherical particles .
Further, in the developing method of the present invention, the magnetic one-component developer carried on the surface of the non-magnetic sleeve is retained on the surface of the photoconductor drum which is installed with a certain gap from the non-magnetic sleeve. In the developing method of transferring to an electrostatic latent image for development, the magnetic one-component developer of the present invention is used as the magnetic one-component developer.
It is characterized in that a minute developer is used.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. <Magnetic Toner> The magnetic toner used in the present invention contains at least a binder resin and a magnetic substance, and if necessary, a colorant, a charge control agent and the like. The volume average particle diameter of the magnetic toner is not particularly limited, but is preferably 5 to 20 μm.

Examples of the binder resin include polystyrene, poly-p-chlorostyrene, polyvinyltoluene,
Styrenes such as styrene-p-chlorostyrene copolymers and styrene-vinyltoluene copolymers, homopolymers of styrene and its substitution products and copolymers thereof; styrene-methyl acrylate copolymers, styrene-ethyl acrylate copolymers Copolymers of styrene and acrylates such as polymer, styrene-n-butyl acrylate copolymer; styrene-
Copolymers of styrene and methacrylic acid ester such as methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-methacrylic acid-n-butyl copolymer; styrene and acrylic acid ester and methacrylic acid ester Other styrene copolymers; styrene-acrylonitrile copolymer, styrene vinyl methyl ether copolymer, styrene butadiene copolymer, styrene vinyl methyl ketone copolymer, styrene acrylonitrile indene copolymer, styrene-maleic acid ester Styrene-based copolymers of styrene and other vinyl-based monomers such as copolymers; polymethyl methacrylate, polybutyl methacrylate, polyester resins, polyvinyl acetate polyester, polyamide resins, epoxy resins, polyvinyl butyral, polyac Le acid, phenol resins, aliphatic or alicyclic hydrocarbon resins, petroleum resins, chlorinated paraffin, and the like. These can be used alone or as a mixture.

As the magnetic material, for example, cobalt, iron,
Metals such as nickel, aluminum, cobalt, copper, iron,
Used for nickel, magnesium, tin, zinc, gold, silver, selenium, titanium, tungsten, zirconium, alloys of other metals, metal oxides such as aluminum oxide, iron oxide, nickel oxide, ferromagnetic ferrite, magnetite or mixtures thereof. To be The average particle size of the magnetic substance is not particularly limited, but is preferably 0.05 to 3 μm. Further, the content of the magnetic substance is 65 with respect to the magnetic toner.
It is preferably less than or equal to weight%.

As the colorant, for example, the following pigments or dyes can be used. Carbon black, aniline blue (CINo.50405), calco oil blue (CI
No.azoec Blue 3), Chrome Yellow (CINo.1409
0), Ultramarine Blue (CINo.77103), DuPont Oil Red (CINo.26105), Orient Oil Red # 330 (CINo.47005), Methylene Blue Chloride (CINo.52015), Phthalocyanine Blue (CINo.7).
4160), malachite green oxalate (CINo.420
00), Lamp Black (CINo.77266), Rose Bengal (CINo.45435) and mixtures thereof.

As the charge control agent, for the (+) toner,
Nigrosine-based electron-donating dyes, metal salts of naphthenic acid and higher fatty acids, alkoxylated amines, quaternary ammonium salts, alkyd amides, phosphorus, tungsten, molybdic acid lake pigments, fluorine treatment activators and the like are used.
For the (−) toner, an electron-accepting organic complex, chlorinated paraffin, chlorinated polyester, polyester having excess acid groups, sulfonylamine of copper phthalocyanine and the like are used.

<Composite Spherical Particles> The composite spherical particles in the present invention are substantially spherical particles having a volume average particle diameter of 5 to 100 μm in which a plurality of fine magnetic substances are contained in a thermosetting resin. Is. With the composite spherical particles having a volume average particle diameter of less than 5 μm, the effect of preventing the memory phenomenon cannot be obtained, and when it is more than 100 μm, the black solid image portion and the halftone image portion become non-uniform and streaky white spots occur. Cheap. The surface of the composite spherical particles may be coated with a metal or may contain a conductive material such as carbon black.

The magnetic material used for the composite spherical particles includes
For example, magnetite particles, maghemite particles, particles obtained by depositing or containing cobalt on these, hematite particles, ferric hydroxide particles, ferrite particles containing barium or strontium, and metal selected from manganese, nickel, zinc and the like. Iron oxide particles such as spinel ferrite particles containing one or more of the above can be used.
The particle form of these magnetic materials may be any of a cubic form, a polyhedral form, a spherical form, a needle form, a plate form and the like. The average particle size of the magnetic material may be smaller than the average particle size of the target composite spherical particles, and is preferably 0.01 to 5 μm, particularly preferably 0.1 to 2 μm. The ratio of the magnetic substance is preferably 85 to 95% by weight in the composite spherical particles. If the content of the magnetic material is less than 85% by weight, the adhesion to the non-magnetic sleeve due to the magnetic force is weakened and the flying easily occurs, which may cause white spots and the like to disturb the image. If it exceeds 95% by weight, the resin component is reduced, so that the durability of the composite spherical particles themselves is impaired and the composite spherical particles are crushed, which may cause contamination on the photosensitive drum or adversely affect the image. There is a risk.

Examples of the thermosetting resin include epoxy resin and phenol resin. When an epoxy resin is used as the thermosetting resin, in the presence of a magnetic substance, bisphenols and epihalohydrin are reactively cured in an alkaline aqueous medium, or an uncured epoxy resin is cured in an aqueous medium. Thus, composite spherical particles composed of magnetic particles and cured epoxy resin can be obtained.

Specifically, an alkaline aqueous medium containing a magnetic substance, bisphenols and epihalohydrin is heated to a temperature in the range of 60 to 90 ° C. with stirring in the presence of a curing agent, and then for about 1 to 5 hours. A polymerization reaction proceeds, or an aqueous medium containing a magnetic material and an uncured epoxy resin is added,
While stirring in the presence of a curing agent, the temperature is raised to a temperature in the range of 60 to 90 ° C., the curing reaction is allowed to proceed for about 1 to 8 hours, and then solid-liquid separation is performed by a usual method such as filtration or centrifugation. Then, the obtained solid is washed with water, heated and dried to obtain composite spherical particles composed of magnetic particles and an epoxy resin.

Examples of bisphenols include bisphenol A, bisphenol F, bisphenol S,
A compound having two or more phenolic hydrogen groups such as resorcin can be used. The amount of bisphenols used is 0.5 to 25% by weight based on the magnetic material. Examples of epihalohydrin include epichlorohydrin,
Epibromhydrin, epiiodohydrin and the like can be used. The molar ratio of bisphenols to epihalohydrin is 0.5 to 1.0: 1.0.

The alkaline aqueous medium is obtained by adding an alkaline compound such as sodium hydroxide or potassium hydroxide to water. As the curing agent, for example, acid anhydrides, amines, etc., which are widely known as curing agents for epoxy resins, can be used. As the uncured epoxy resin, for example, epoxy compounds having two or more epoxy groups in the molecule such as bisphenol A glycidyl ether at both ends and polyethylene glycol glycol glycidyl ether at both ends can be used.

On the other hand, when a phenol resin is used as the thermosetting resin, in the presence of a magnetic substance and a basic catalyst,
By reacting and curing a phenol or a phenol resin and an aldehyde with stirring in an aqueous medium,
It is possible to obtain composite spherical particles composed of magnetic particles and cured phenol resin. The curing reaction is carried out in an aqueous medium, and the amount of water charged in this case is preferably such that the total solid content concentration is 30 to 95% by weight, particularly 60 to 90% by weight.

Examples of phenols include, in addition to phenol, alkylphenols such as m-cresol, p-tert-butylphenol, o-propylphenol, resorcinol, and bisphenol A, and benzene nucleus or part or all of the alkyl group. Examples thereof include compounds having a phenolic hydroxyl group such as halogenated phenols substituted with an atom or a bromine atom. The phenol resin may be any of a novolac type resin, a resol type resin, and a natural resin modified resin, but a resin soluble in a water-soluble solvent such as alcohol or acetone is preferable.

Examples of aldehydes include formaldehyde and furfural in the form of formalin or paraformaldehyde. Of these, formaldehyde is preferable. The molar ratio of aldehydes to phenols (phenolic resin) is preferably 1 to 4,
More preferably, it is 1.2-3. When the molar ratio is less than 1, the composite spherical particles are hard to be produced, and even if they are produced, the strength of the resin tends to be weak. On the other hand, when the molar ratio exceeds 4, the amount of unreacted aldehydes remaining in the aqueous medium after the reaction tends to increase.

As the basic catalyst, a basic catalyst used in the usual production of resole resins can be used, and examples thereof include aqueous ammonia, alkylamines such as hexamethylenetetramine, diethyltriamine and polyethyleneimine. The amount of these basic catalysts to phenols (phenolic resin) is 0.02 to 0.
7 is preferable.

The amount of the complex spherical particles to be contained in the magnetic one-component developer, the volume average particle diameter of the composite spherical particles, as appropriate, adjust. The volume average particle diameter of the composite spherical particles, in the case of less than 5 [mu] m 15 [mu] m, the composite spherical particles Ru is contained 1 to 15% by weight in the magnetic one-component developer. 1
If it is less than the weight, it is difficult to obtain the effect of preventing the memory phenomenon, and if it exceeds 15% by weight, the black solid image portion and the halftone image portion tend to become non-uniform. The volume average particle diameter of the composite spherical particles, in the case of less than 15 [mu] m 35 [mu] m, the composite spherical particles Ru is contained 5 to 50% by weight in the magnetic one-component developer. If it is less than 5% by weight, the effect of preventing the memory phenomenon is difficult to obtain, and if it exceeds 50% by weight, black solid image portions and halftone image portions become non-uniform and streak-like blank areas are likely to occur.

[0029] The volume average particle diameter of the composite spherical particles, in the case of 35～100Myuemu, complex spherical particles Ru is contained 1-5 wt% in the magnetic one-component developer. If it is less than 1% by weight, it is difficult to obtain the effect of preventing the memory phenomenon, and if it exceeds 5% by weight, the black solid image portion and the halftone image portion become non-uniform, and streak-like white spots are likely to occur. Especially 35
In the magnetic one-component developer containing 1 to 5% by weight of the composite spherical particles of ˜100 μm, the image density is easier and the image characteristics are better than the case of containing the composite spherical particles of other volume average particle size. Above all preferred. This is because the volume average particle diameter of the composite spherical particles is large, so that the composite spherical particles widen the gap between the non-magnetic sleeve and the magnetic blade, the amount of the magnetic one-component developer passing through increases, and It is speculated that this is because the charge injection into the magnetic one-component developer by the blade is sufficiently performed.

[0030] The present invention odor Te is, by containing a complex spherical particles in the magnetic one-component developer, thereby reducing the occurrence of blur and memory phenomena of the image. This is because the spherical particles of the composite are agitated with the magnetic toner in the hopper to improve the triboelectric charge amount of the magnetic toner, and in the magnetic one-component developer on the surface of the non-magnetic sleeve. It is considered that the composite spherical particles have a function of releasing the triboelectric charge amount of the magnetic toner, and an appropriate triboelectric charge amount is imparted to the magnetic toner.

<Developing Method> Next, the developing method of the present invention using the above magnetic one-component developer will be described in detail.
FIG. 1 is a schematic view of a developing device used in the method for developing a magnetic one-component developer of the present invention. This developing device is installed with a cylindrical photosensitive drum 1 serving as an electrostatic latent image holder, a hopper 2 containing a magnetic one-component developer 3, and a constant gap with respect to the photosensitive drum 1. The right half-circumferential surface is housed in the hopper 2, and the left half-circumferential surface faces the photoconductor drum 1, a non-magnetic sleeve 6 made of aluminum, a magnet roller 5 contained in the non-magnetic sleeve 6, and a non-magnetic sleeve. 6, a magnetic blade 4 for making the layer of the magnetic one-component developer 3 carried by 6 uniform in thickness, a stirrer 7 for stirring the magnetic one-component developer 3 in the hopper 2, and a non-magnetic sleeve 6. The magnetic blade 4 is electrically connected to the photosensitive drum 1, and a power source 8 for applying an alternating bias voltage and a DC bias voltage to the photosensitive drum 1 is provided. The gap between the non-magnetic sleeve 6 and the photosensitive drum 1 is about 50-4.
It is set to 00 μm.

The developing method of the magnetic one-component developer of the present invention using this developing apparatus is carried out as follows. First,
An electrostatic latent image is formed on the surface of the photosensitive drum 1 by a known electrophotographic method. On the other hand, the magnetic one-component developer 3 in the hopper 2 is transferred to the magnet roller 5 by the magnetic blade 4.
Is carried on the surface of the non-magnetic sleeve 6 enclosing it so as to have a constant layer thickness, and conveyed. Here, by applying an alternating bias voltage and a DC bias voltage from the power source 8 to the photosensitive drum 1, a DC electric field and an AC electric field are generated between the non-magnetic sleeve 6 and the photosensitive drum 1, and the non-magnetic sleeve 6 The magnetic one-component developer 3 on the surface is jumped and developed into an electrostatic latent image on the surface of the photosensitive drum 1.

[0033]

The present invention will be described in more detail based on the following examples. [Preparation of Magnetic Toner] 57 parts by weight of styrene-acrylic acid ester copolymer resin (CPR-100 manufactured by Mitsui Chemicals, Inc.), magnetite particles (EPT-100 manufactured by Toda Kogyo Co., Ltd.)
0) 38 parts by weight, 2 parts by weight of a metal-containing dye (BONTRON S-34 manufactured by Orient Chemical Industry Co., Ltd.), and 3 parts by weight of a low molecular weight polypropylene wax (Viscole 330P manufactured by Sanyo Chemical Industry Co., Ltd.) were mixed with a super mixer,
After hot melt kneading with a twin-screw kneader, pulverize with a jet mill and then classify with a dry classifier to obtain a volume average particle size of 9.5 μm.
Toner particles were obtained. Then, the toner particles and hydrophobic silica (TS-530, manufactured by Cabot Corporation) were charged into a Henschel mixer at a ratio of 1% by weight of the hydrophobic silica to the weight of the toner particles, and the circumference of the stirring blade was changed. Speed is 20
A magnetic toner was prepared by mixing for 5 minutes under the condition of m / s.

Example 1 The above magnetic toner and composite spherical particles having a volume average particle diameter of 10.4 μm (90% by weight of spherical magnetite particles having a volume average particle diameter of 0.24 μm were contained in a phenol resin. Of the composite spherical particles are mixed in a V blender at a ratio of 10% by weight and mixed for 5 minutes under the condition that the peripheral speed of the V blender is 35 rpm to obtain the magnetic one-component developer of the present invention. It was

[Example 2] The mixing ratio of the composite spherical particles was adjusted to 5
A magnetic one-component developer of the present invention was obtained in the same manner as in Example 1 except that the weight percentage was changed. [Example 3] A magnetic one-component developer of the present invention was obtained in the same manner as in Example 1 except that the mixing rate of the composite spherical particles was changed to 15% by weight.

[Example 4] The above magnetic toner and composite spherical particles having a volume average particle diameter of 6.5 µm (90% by weight of spherical magnetite particles having a volume average particle diameter of 0.24 µm were contained in a phenol resin. Of the composite spherical particles are mixed in a V blender at a ratio of 10% by weight and mixed for 5 minutes under the condition that the peripheral speed of the V blender is 35 rpm to obtain the magnetic one-component developer of the present invention. It was

[Example 5] The above magnetic toner and composite spherical particles having a volume average particle diameter of 14.2 µm (90% by weight of spherical magnetite particles having a volume average particle diameter of 0.24 µm were contained in a phenol resin. Of the composite spherical particles are mixed in a V blender at a ratio of 10% by weight and mixed for 5 minutes under the condition that the peripheral speed of the V blender is 35 rpm to obtain the magnetic one-component developer of the present invention. It was

Example 6 The above magnetic toner and composite spherical particles having a volume average particle diameter of 27 μm (90% by weight of spherical magnetite particles having a volume average particle diameter of 0.24 μm in a phenol resin). Are charged into a V blender at a ratio of 25% by weight of the composite spherical particles,
The magnetic blender of the present invention was obtained by mixing for 5 minutes under the condition that the peripheral speed of the V blender was 35 rpm.

[Example 7] The mixing ratio of the composite spherical particles was adjusted to 5
A magnetic one-component developer of the present invention was obtained in the same manner as in Example 6 except that the content was 0% by weight. [Example 8] A magnetic one-component developer of the present invention was obtained in the same manner as in Example 6 except that the mixing ratio of the composite spherical particles was changed to 5% by weight.

Example 9 The above magnetic toner and composite spherical particles having a volume average particle diameter of 16.2 μm (90% by weight of spherical magnetite particles having a volume average particle diameter of 0.24 μm were contained in a phenol resin. Of the composite spherical particles are mixed in a V blender at a ratio of 25% by weight and mixed for 5 minutes under the condition that the peripheral speed of the V blender is 35 rpm to obtain the magnetic one-component developer of the present invention. It was

[Example 10] The above magnetic toner and composite spherical particles having a volume average particle diameter of 33.8 µm (90% by weight of spherical magnetite particles having a volume average particle diameter of 0.24 µm were contained in a phenol resin. Of the composite spherical particles are mixed in a V blender at a ratio of 25% by weight and mixed for 5 minutes under the condition that the peripheral speed of the V blender is 35 rpm to obtain the magnetic one-component developer of the present invention. It was

Example 11 The above magnetic toner and composite spherical particles having a volume average particle size of 63.4 μm (90% by weight of spherical magnetite particles having a volume average particle size of 0.24 μm were contained in a phenol resin. Of the composite spherical particles are mixed in a V blender at a ratio of 3% by weight and mixed for 5 minutes under the condition that the peripheral speed of the V blender is 35 rpm to obtain the magnetic one-component developer of the present invention. It was

[Example 12] A magnetic one-component developer of the present invention was obtained in the same manner as in Example 11 except that the mixing ratio of the composite spherical particles was changed to 5% by weight. [Example 13] A magnetic one-component developer of the present invention was obtained in the same manner as in Example 11 except that the mixing ratio of the composite spherical particles was set to 1% by weight.

[Example 14] The above magnetic toner and composite spherical particles having a volume average particle diameter of 37.9 µm (90% by weight of spherical magnetite particles having a volume average particle diameter of 0.24 µm were contained in a phenol resin. Of the composite spherical particles are mixed in a V blender at a ratio of 3% by weight and mixed for 5 minutes under the condition that the peripheral speed of the V blender is 35 rpm to obtain the magnetic one-component developer of the present invention. It was

[Example 15] The above magnetic toner and composite spherical particles having a volume average particle diameter of 96.8 µm (90% by weight of spherical magnetite particles having a volume average particle diameter of 0.24 µm were contained in a phenol resin. Of the composite spherical particles are mixed in a V blender at a ratio of 3% by weight and mixed for 5 minutes under the condition that the peripheral speed of the V blender is 35 rpm to obtain the magnetic one-component developer of the present invention. It was

Comparative Example 1 Only the magnetic toner was used as a magnetic one-component developer without mixing the composite spherical particles. Comparative Example 2 The volume average particle diameter of the magnetic toner is 3.
8 μm composite spherical particles (containing 90% by weight of spherical magnetite particles having a volume average particle size of 0.24 μm in a phenol resin) at a ratio of 10% by weight of the composite spherical particles. The mixture was put into a blender and mixed for 5 minutes under the condition that the peripheral speed of the V blender was 35 rpm to obtain a magnetic one-component developer for comparison.

Comparative Example 3 The above magnetic toner and composite spherical particles having a volume average particle diameter of 105.4 μm (90% by weight of spherical magnetite particles having a volume average particle diameter of 0.24 μm are contained in a phenol resin. Of the composite spherical particles are mixed in a V blender at a ratio of 3% by weight, and mixed for 5 minutes under the condition that the peripheral speed of the V blender is 35 rpm to obtain a magnetic one-component developer for comparison. It was

[Comparative Example 4] A magnetic one-component developer for comparison was obtained in the same manner as in Example 1 except that the mixing ratio of the composite spherical particles was changed to 0.5% by weight. [Comparative Example 5] A magnetic single-component developer for comparison was obtained in the same manner as in Example 6 except that the mixing ratio of the composite spherical particles was changed to 55% by weight.

[Evaluation Method] The following tests were carried out on the magnetic one-component developers of the above Examples and Comparative Examples. That is, using the magnetic one-component developers of the above-mentioned Examples and Comparative Examples, a Casio printer 4150II having a developing device configuration as shown in FIG. 1 was used to produce an original having the pattern shown in FIG. 2 four times. Printed, then black solid image. Further, the original of FIG. 2 was printed four times by the same printer, and then a halftone image was printed. And
With respect to the above black solid image and halftone image, image density, black solid memory, and halftone memory were evaluated. The test results are shown in Table 1. In Table 1, the image density is a value obtained by measuring the black solid image portion of FIG. 2 printed for the first time with a reflection densitometer RD-914 manufactured by Macbeth.

Further, the black solid memory was obtained as follows. In the solid black image after the original document of FIG. 2 has been printed four times, the solid black portions 10a, 10b, 10c of FIG.
The part suitable for 10d is a reflection densitometer RD- manufactured by Macbeth.
The average value of the image densities at these four points was defined as A. On the other hand, the white parts 20a, 20b, 20c, 20 of FIG.
The portion matching d is the reflection densitometer RD-91 manufactured by Macbeth.
4 and the average value of the image densities at these four points is designated as B. Then, the value of A-B was evaluated as a black solid memory.

The halftone memory was determined as follows. In the halftone image after printing the document of FIG. 2 four times, the black solid portions 10a and 10 of FIG.
The areas corresponding to b, 10c, and 10d were measured with a reflection densitometer RD-914 manufactured by Macbeth Co., and the average value of the image densities at these four points was defined as C. On the other hand, the white parts 20a, 20b in FIG.
A portion corresponding to 20c and 20d is measured by a reflection densitometer RD-914 manufactured by Macbeth Co., and an average value of image densities at these four points is defined as D. Then, the value of CD was evaluated as a halftone memory.

The values of the black solid memory and the halftone memory nearer to 0 indicate that the image has no memory phenomenon. The image quality is the result of visual evaluation of the solid black image and the halftone image printed the fifth time.

[0053]

[Table 1]

As shown in Table 1 above, the magnetic one-component developer of the present invention and its developing method can obtain an image with little black solid memory and halftone memory while maintaining the uniformity of black solid and halftone. You can

[0055]

As described above, the magnetic one-component developer of the present invention contains a magnetic toner containing a binder resin and a magnetic substance, a thermosetting resin and a magnetic substance, and has a volume average particle diameter. Of spherical particles 1 having a particle size of 5 μm or more and less than 15 μm
Since the content is up to 15 % by weight, it is possible to increase the image density and reduce the occurrence of image blur and memory phenomenon.
Sufficient developability can be obtained. In addition, the magnetic property of the present invention
The one-component developer is a magnetic toner containing a binder resin and a magnetic material.
Solution containing thermosetting resin and magnetic material
A composite spherical shape having an average particle size of 15 μm or more and less than 35 μm
A magnetic one-component developer having 5 to 50% by weight of particles.
When the content of the magnetic substance in the magnetic toner is 65% by weight or less,
Yes, the content of the magnetic material in the composite spherical particles is 85 to 95
Since it is the weight%, the image density is increased and the image
It is possible to reduce the occurrence of scratches and memory phenomenon of
Sufficient developability can be obtained. In addition, the magnetic property of the present invention
The one-component developer is a magnetic toner containing a binder resin and a magnetic material.
Solution containing thermosetting resin and magnetic material
Composite spherical particles 1 having a uniform particle diameter of 35 to 100 μm
5% by weight, the image density is high.
To reduce image blur and memory phenomenon.
It is possible to obtain sufficient developability. Further, in the developing method of the present invention, the magnetic one-component developer carried on the surface of the non-magnetic sleeve is retained on the surface of the photoconductor drum which is installed with a certain gap from the non-magnetic sleeve. In the developing method of developing by transferring to a latent image, since the magnetic one-component developer of the present invention is used as the magnetic one-component developer , the image density is high, and image blur and memory phenomenon An image with reduced occurrence can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a developing device used in a non-contact type magnetic one-component developing method.

FIG. 2 is a diagram showing an image pattern used for image evaluation in Examples.

[Explanation of symbols]

1 ... Photosensitive drum, 3 ... Magnetic one-component developer, 6 ... Non-magnetic sleeve

─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-6-161149 (JP, A) JP-A-8-194333 (JP, A) JP-A-9-146297 (JP, A) JP-A-8- 40724 (JP, A) JP-A-6-110247 (JP, A) JP-A-6-95511 (JP, A) JP-A-56-16145 (JP, A) JP-A-60-220362 (JP, A) JP 10-39547 (JP, A) JP 3-152553 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/08-9/10 G03G 15/09 101

Claims (6)

(57) [Claims] 1. A magnetic toner containing a binder resin and a magnetic material, containing a thermosetting resin and a magnetic material, and the volume average particle diameter of 5 [mu] m or more 15μm below a is composite spherical particles 1-1
And a magnetic one-component developer having a content of 5 % by weight. 2. A magnetic toner containing a binder resin and a magnetic material.
And a thermosetting resin and a magnetic substance, and has a volume average particle size.
5 to 15 μm or more and less than 35 μm
A magnetic one-component developer having an amount of 50% by weight, wherein the content of the magnetic substance in the magnetic toner is 65% by weight or less.
The magnetic substance content in the composite spherical particles is 85 to 95
Magnetic one-component developer characterized in that an amount%. 3. A magnetic toner containing a binder resin and a magnetic material.
And a thermosetting resin and a magnetic substance, and has a volume average particle size.
1 to 5% by weight of composite spherical particles having a particle size of 35 to 100 μm
Magnetic one-component developer, comprising and. 4. A magnetic material carried on the surface of a non-magnetic sleeve.
A one-component developer with a constant gap to the non-magnetic sleeve.
Static electricity held on the surface of the installed photoconductor drum
In the developing method of transferring to a latent image and developing, a binder resin and a magnetic substance are contained as the magnetic one-component developer.
Contains magnetic toner, thermosetting resin and magnetic material
And the volume average particle size is 5 μm or more and less than 15 μm
A composite spherical particle having 1 to 15% by weight is used.
A developing method comprising: 5. A magnetic one-component developer carried on the surface of a non-magnetic sleeve is converted into an electrostatic latent image held on the surface of a photoconductor drum which is installed with a certain gap from the non-magnetic sleeve. In a developing method of transferring and developing, as the magnetic one-component developer, a magnetic toner containing a binder resin and a magnetic substance, a thermosetting resin and a magnetic substance are contained, and the volume average particle diameter is 15 μm or more. der those with complex and the spherical particles 5 to 50 wt% less than 35μm
The magnetic toner content in the magnetic toner is 65% by weight or less.
And the content of the magnetic material in the composite spherical particles is 85 to 9
A developing method, characterized in that 5% by weight is used. 6. A magnetic material carried on the surface of a non-magnetic sleeve.
A one-component developer with a constant gap to the non-magnetic sleeve.
Static electricity held on the surface of the installed photoconductor drum
In the developing method of transferring to a latent image and developing, a binder resin and a magnetic substance are contained as the magnetic one-component developer.
Contains magnetic toner, thermosetting resin and magnetic material
And having a volume average particle diameter of 35 to 100 μm
Use of those having 1 to 5% by weight of spherical particles
And a developing method.