JPH07295289A - Production of non-magnetic one component developer - Google Patents

Abstract

PURPOSE:To produce a negatively chargeable non-magnetic one component developer capable of providing a distinct picture due to sufficient reduction of fogging from low charge potential to high potential of a photoreceptor and wide in a developing condition. CONSTITUTION:0.1-10wt.% fluororesin fine powder having 4-20mum wt. average grain size and whose fine powder content having <=37mum grain size is 130wt.% is added to a toner consisting essentially of a thermoplastic binding resin and a colorant. In this case. polyester resin, etc., are used as the thermoplastic binding resin and polytetrafluoroethylene fine powder is used as the fluororesin fine powder to be added preferably. Moreover appropriately, an addition of an inorg. fine powder subjected to treatment to change into hydrophobic is use jointly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-magnetic one-component developer used for developing an electrostatic latent image in electrophotography, electrostatic recording, electrostatic printing, etc. by a non-magnetic one-component developing method. More specifically, there is no stain (fog) on the non-image area over a wide range of developing conditions, or over time with changes in the developing device including a developer and a photoreceptor associated with repeated development, and excellent resolution, The present invention relates to a negatively chargeable non-magnetic one-component developer capable of obtaining a clear image having high image density.

[0002]

2. Description of the Related Art A method of developing an electrostatic latent image is well known in the art, and for example, in electrophotography, a uniformly charged photoreceptor layer composed of selenium, zinc oxide, vinylcarbazole compound, cadmium sulfide, phthalocyanine compound, etc. To the electrostatic latent image obtained by exposing the same photo image as the original image to eliminate the electrostatic charge on the photoconductor, and electrostatically attaching the toner composed of the binder resin, the colorant, and other additives to the electrostatic latent image. It is performed by forming a toner image by adhesion. The obtained toner image is transferred to an image support such as paper, if necessary, and then melted by heating, the toner is softened or melted by a solvent, or the toner is deformed by pressure to form an image support. Permanently fixed.

In the electrostatic latent image developing method, a toner and a photoconductor having the same polarity as a so-called regular developing method, in which the toner and the photoconductor are opposite in polarity depending on the polarities of the charged toner and the photoconductor, are used. And a developing bias is applied to the photoconductor to perform development, and the reversal development method is used. Further, various methods such as a cascade method, a powder cloud method, a magnetic brush method, a jumping method, and a touchdown method are known as methods relating to the supply of the developer to the photoconductor for each of the developing methods. The electrostatic image developers used for development are roughly classified into two-component developers and one-component developers depending on the developing method. The two-component developer is toner and iron powder having a larger particle size than the toner,
The electrostatic latent image is developed by a toner, which is composed of carriers such as steel balls, ferrite, and glass beads, and which is charged by frictional charging with the carrier. The one-component developer further contains a magnetic material such as iron tetroxide, iron sesquioxide, ferrite, etc. in the toner so that the developer layer formed on the developer carrier using the magnetic force can be electrostatically charged. It is classified into a magnetic one-component developer that develops a latent image and a non-magnetic one-component developer that develops an electrostatic latent image with a developer layer formed on a developer carrier by contact charging, friction charging, etc. .

The developing method using a non-magnetic one-component developer is a method of developing an electrostatic latent image without using a carrier and a magnetic material as described above, and the developing device can be downsized and simplified. There are advantages. The developing device has at least a layer forming member for imparting an electrostatic charge to the developer by contact charging, triboelectric charging, and forming a developer layer having a uniform thickness, and a developer carrying member. Currently, a developing device using a contact developing method, which supplies a developer to the surface of an electrostatic latent image for development by bringing a photosensitive member on which an electrostatic latent image is formed into contact with each other, is most widely used at present.

As the above-mentioned toner, generally, a thermoplastic resin is used as a binder resin, and the resin contains a colorant, a charge control agent, and
A fine powder is used in which other additives are melt-kneaded and dispersed, and then the composition is finely pulverized and classified to have a particle size of 5 to 30 μm. Further, a developer in which other substances are added to the toner for the purpose of imparting the properties required as an electrostatic image developer is also known.

As the above-mentioned thermoplastic resin, conventional styrene resin, acrylic resin, styrene-acrylic copolymer resin,
Vinyl-based resin such as styrene-butadiene copolymer resin, or polyester resin, epoxy resin, polyamide resin, polyurethane, polycarbonate, fluorine-based resin,
Silicone resin, phenol resin, maleic acid resin,
Although coumarone resin and the like are known, among them, polyester resin is particularly (a) charging property, (b) fixing property, (c)
It is excellent in transparency, (d) glossiness, and (e) vinyl chloride migration resistance, and has been put into practical use in recent years as a binder resin for toner.

On the other hand, an electrostatic charge image developer obtained by adding a fluorine-based resin fine powder to a toner is used for the purpose of preventing the so-called filming phenomenon in which the toner adheres to the photosensitive layer during repeated development, which is disclosed in JP-B-51-1130. Disclosed in JP-B-48-8141 and JP-A-54-126031, a developer containing polymer particles which are electrically more negative than sulfur in a triboelectric system. A developer to which polymer particles having a free energy smaller than that of the toner is added, and a developer to which low molecular weight polytetrafluoroethylene fine powder is added, which is disclosed in JP-A-1-281459, is known.

The most important thing in the development of the electrostatic latent image using such an electrostatic image developer is the quality of the finally obtained image, that is, the charging potential of a wide range of the photoreceptor or the electrostatic latent image. Contamination of the non-image area (fogging) and disturbance of the edge of the image area against development conditions such as image potential, or changes over time in a developing device including a developer and a photoconductor due to repeated development. There is a need for a developer that provides excellent resolution and high image density. In particular, there is an extremely high demand for reducing the fogging caused by the developer electrostatically adhering to the non-image area of the photoconductor after the photoimage exposure, that is, the unexposed area of the photoconductor that continues to retain electric charges. However, great efforts have been made so far to reduce the fog.

Conventionally, in order to solve the above problems, for example,
Addition of inorganic fine inorganic powder as disclosed in JP-B-2-10419, addition of conductive fine particles disclosed in JP-A-62-184473, or silane-based surface treatment agent, Many methods are known, such as addition of an inorganic fine powder that has been subjected to a hydrophobic treatment with a fluorine-based surface treatment agent or a titanium-based surface treatment agent, a method of adding the fine powder, and an improvement of a charge control agent and a binder resin.

Certainly, when the electrostatic latent image is developed by using the developer produced by the above method, there is no fog or disturbance of the image edge portion under a specific developing method and developing condition, and an excellent resolution is obtained. In some cases, an image having a high image density can be obtained.

[0011]

However, when an electrostatic latent image is developed by the non-magnetic one-component developing method using the developer disclosed in the above publication, the image quality of the obtained image does not always meet the above requirements. I'm not satisfied. Binder resin,
Depending on the combination of the constituent materials of the above-mentioned developer such as the charge control agent and the additive, the opposite effect may be exerted, which may cause remarkable fog. Further, even when a clear image without fog is obtained by the developer, the effect of the developer on the image quality is recognized only under a narrow developing condition, which facilitates the design of the developing device. A developer satisfying the requirements has not been obtained for a wide range of developing conditions, or for a developer accompanying repeated development and a change with time of a developing device including a photoconductor.

As an example of the change of fog with respect to the developing conditions, the charging potential of the photoconductor under the developing conditions, the developer, the photoconductor, and the negative charging non-magnetic one-component developer depending on the developing method,
A change in fog with respect to the charging potential in the case of using a negatively chargeable photoreceptor and reversal development for developing an electrostatic latent image by applying a developing bias will be described in detail.

By using the developer and the developing method, only the charging potential of the surface of the photosensitive member can be arbitrarily changed within a range of 0V to the practical charging potential of the photosensitive member which does not cause dielectric breakdown in the negative polarity. The electrostatic latent image is developed with a potential. As described above, the toner image on the photoconductor developed with various charging potentials, or the fogging in the image transferred and fixed on the image support such as paper changes depending on the charging potential, and The change in fogging greatly depends on the developer used.
As the charging potential is increased from 0 V to the negative polarity, the static electricity between the non-image portion of the photoconductor after the photoimage exposure, that is, the unexposed portion of the photoconductor that continues to hold the negative charge and the developer. Repulsive force increases. Therefore, the electrostatic repulsion force is increased by the charging potential, and electrostatic adhesion of toner to the non-image portion is less likely to occur, whereby the fog is gradually reduced and the image sharpness tends to be improved. It is in. Further, as the charging potential is further increased to the negative polarity, the fog is most reduced at a certain charging potential, that is, the fog becomes minimum and then saturated. Alternatively, although the detailed reason is unknown, depending on the developer, the fog may gradually increase together with the charging potential.

As described above, the fog tends to gradually decrease with the charging potential and then become saturated, or to increase again after a certain minimum value. At a certain charging potential, the fog is reduced and an image with improved sharpness is obtained. can get.

However, in the case of the conventional non-magnetic one-component developer or the developer disclosed in the above-mentioned publication, when the developing is carried out by using the charging potential which minimizes the fog within the range of the practical charging potential of the photoreceptor. Even in this case, it is not possible to obtain a clear image with sufficiently reduced fogging that can be put to practical use. Alternatively, even when an image in which fogging is sufficiently reduced by the charging potential is obtained, it is necessary to use a high negative potential as the charging potential. Alternatively, when the charging potential is further increased beyond the surface potential in the negative polarity, a remarkable increase in fog occurs and an image that can be put to practical use cannot be obtained.

When there is a photoconductor charging potential capable of producing a clear image with reduced fog which can be put to practical use, when the photoconductor charging potential is increased from 0 V to a negative polarity, the potential is such that the image is obtained. The fog that occurs in the potential range of is referred to as the low-pressure side fog. Further, the fog generated when the fog that can be put to practical use is obtained, or when the fog is remarkably increased over the electric potential range is referred to as high-pressure fog. The size of the potential range in which the image that can be practically used is obtained is indicated by the absolute value of the difference between the fog generation potential on the high voltage side and the fog generation potential on the low voltage side. FIG. 1 described later shows an example of a change in fog density on the photoconductor described later when the photoconductor charging potential is arbitrarily changed within the practical potential range of the potential.

That is, in the conventionally known developer, when the electrostatic latent image is developed, there is no photoconductor charging potential that can provide a clear image with reduced fog that can be put to practical use, or , Fog is generated on the low voltage side to a high potential in the negative polarity, and a high potential is required to obtain the image, or fog is generated on the high voltage side from a low potential on the negative polarity in addition to the fog on the low voltage side. There is a problem that the potential range in which an image can be obtained is extremely narrow, and the above requirements cannot be satisfied.

In addition, the toner disclosed in JP-B-51-1130, JP-B-48-8141, JP-A-54-126031, and JP-A-1-281459 is mixed with a fluorine resin fine powder. The electrostatic image developer is limited to the purpose of preventing cleaning failure and filming of the photoconductor due to toner physically and chemically adhering to the photoconductor. Therefore, the fogging is a stain caused by the developer electrostatically adhering to the non-image portion on the photosensitive member on which the electrostatic latent image is formed. Mixing does not solve the fog that occurs depending on the surface potential of the photoconductor.
In the publication, for example, surface free energy of resin fine powders to be mixed and triboelectric charging series are defined, and mixing of fluororesin fine powders such as polytetrafluoroethylene fine powder and polyvinylidene fluoride fine powder, and polyethylene fine powder is disclosed. However, the developer mixed with polytetrafluoroethylene fine powder having a large amount of fine powder does not have any effect on the above problems, but rather increases the fog over the practical potential range of the photoconductor and has an adverse effect. Becomes Similarly, a developer in which a fine powder of polyvinylidene fluoride, a fine powder of polyethylene or the like is mixed does not have any effect on the problem, and an image having a sufficient density cannot be obtained. Further, even if the cleaning failure of the photosensitive member and the filming are prevented by improving the cleaning mechanism of the photosensitive member and the photosensitive member, the problem occurs due to the surface potential of the photosensitive member.

The present invention has been made to solve the above-mentioned problems in the prior art.

That is, an object of the present invention is to provide a negatively chargeable non-magnetic one-component developer capable of sufficiently reducing fog and obtaining a clear image having excellent resolution and high image density.

Still another object of the present invention is to provide a wide range of development conditions for obtaining a clear image in which fogging is sufficiently reduced from a low photoconductor charging potential to a high photoconductor potential, and a wide allowable range is set for designing a developing device. A non-magnetic one-component developer to be provided is provided.

Another object of the present invention is to provide a wide range of developing conditions for obtaining a clear image without fog, and to provide a clear image with respect to a change with time of a developing device including a developer and a photoreceptor, which accompanies repeated development. It is intended to provide a non-magnetic one-component developer capable of obtaining various images.

[0023]

Means for Solving the Problems As a result of repeated studies to solve the above-mentioned problems, the inventors have found that a toner containing a thermoplastic binder resin and a colorant as main components is 0.1 to 10% by weight. %
By adding a fluororesin fine powder having a weight average particle diameter of not more than the weight average particle diameter of the above toner and a fine powder content of not more than 3 μm and not more than 30% by weight to a wide range of developing conditions, Alternatively, a non-magnetic single component that gives a clear image with excellent resolution and high image density, with sufficiently reduced fog against changes with time of a developing device including a developer and a photoconductor that accompany repeated development. It was found that a developer can be obtained, and the present invention has been completed.

[0024]

The present invention will be described in detail below. In the present invention, a fluororesin fine powder having an average particle size smaller than that of the toner and having a fine powder content of 3 μm or less and 30% by weight or less can be used.

When the fine powder content of 3 μm or less in the fluorine-based resin fine powder is higher than 30% by weight, the effect of the present invention, that is, the effect of sufficiently reducing fogging by the fine resin powder,
Not only can the resolution not be improved, but the fog can be significantly increased. Further, with respect to the reduction effect of fog generation potential on the low voltage side, the effect of expanding the photoconductor charging potential range in which fog is sufficiently reduced by reducing the fog on the high voltage side, and a wide range of developing conditions that facilitate the design of the developing device, In addition, the effect of reducing fogging and the effect of improving resolution with respect to changes with time of the developing device including the developer and the photoconductor due to repeated development cannot be obtained.

The average particle diameter in the present invention is a median diameter obtained from the weight-based particle diameter distribution of the resin fine powder.
The fine powder content of not more than μm is the weight fraction of fine powder obtained from the distribution. The weight-based particle size distribution is measured by a laser diffraction type particle size distribution measuring device, a Coulter counter (manufactured by Coulter, Inc.), a centrifugal sedimentation method or the like, or a number-based particle size measured by a scanning electron microscope or the like. It is obtained by converting the distribution into a particle size distribution based on weight. The average particle size and the amount of fine powder of the resin fine powder vary greatly depending on the method of measuring the particle size distribution and the method of preparing the measurement sample. Particularly, the resin fine powder is mixed with a suitable dispersant in water or a dispersion medium such as an organic solvent. In the so-called wet method in which the resin fine powder is dispersed and measured, the dispersion of the resin fine powder in the dispersion medium is often insufficient, and it is difficult to obtain an accurate particle size distribution. In the present invention, the fine powder content determined from the weight average particle size and the particle size distribution on a weight basis is HELOS using a dry dispersion unit (RODOS).
& RODOS Laser diffraction type particle size distribution measuring device (manufactured by Sympatech Co., Ltd.). In the present invention, the dispersion of the resin fine powder in the dispersion unit is carried out by an air flow shearing force using compressed air of 5 bar, or a wall collision by attaching the air flow shearing force and a cascade to the unit to obtain an average particle size Measure the diameter distribution.

The average particle size of the fluororesin fine powder may be such that the primary particle size is smaller than the average particle size of the toner, and there is no problem even if they aggregate to form secondary particles. The fluororesin fine powder can be produced by suspension polymerization, low-temperature pulverization of the resin, or pulverization of the resin irradiated with radiation. Further, if necessary, fine powder of 3 μm or less in the fine powder obtained by the manufacturing method or coarse powder larger than the particle diameter of the toner is removed by a classification step to control the average particle diameter and the particle diameter distribution. Can also be used.

The fluororesin used in the present invention includes:
Polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-ethylene copolymer Examples thereof include polymers, polychlorotrifluoroethylene, chlorotrifluoroethylene-ethylene copolymers, polyvinylidene fluoride, polyvinyl fluoride, and mixtures thereof.
Particularly, in the present invention, it is preferable to use polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl ether copolymer, or tetrafluoroethylene-hexafluoropropylene copolymer as the fluorine-based resin. Further, the effect of the present invention is that the molecular weight of the fluororesin fine powder,
The characteristics of the fine powder such as molecular weight distribution, crystallinity and melting point are not limited.

In the present invention, the above-mentioned fluororesin fine powder is used in the range of 0.1 to 10% by weight, preferably 0.2.
It can be added to the toner in the range of ˜7% by weight.

When the amount of the fluorine-based resin fine powder added to the developer is less than 0.1% by weight, the effect of the present invention, that is, the effect of sufficiently reducing the fog by the resin fine powder and the improvement of the resolution are obtained. No effect. Even when the effect is obtained, the effect is recognized only under a narrow developing condition, and the fog is sufficiently reduced by reducing the fog generation potential on the low voltage side and the fog on the high voltage side. The effect of expanding the charging potential range and a wide range of developing conditions that facilitate the design of the developing device, or sufficient fogging with respect to changes over time of the developing device including the developer and the photoconductor due to repeated development Neither reduction effect nor resolution improvement effect can be obtained.

If the amount added exceeds 10% by weight, the fog on the high pressure side increases, the fog generation potential on the high voltage side decreases, the resolution is poor, and the fixing of the developer is poor.

As the method for adding the fluorine-based resin fine powder to the toner, simple mixing of the resin fine powder and the toner, adhesion of the resin fine powder to the toner surface using mechanical shearing force,
A physical method such as immobilization, immobilization of the resin fine powder on the toner surface by the combined use of mixing and heat treatment, or immobilization of the resin fine powder on the toner surface by the combined use of mixing and mechanical impact, or a toner And a chemical method such as immobilization by a covalent bond between the fine powder and a chemical bond such as hydrogen bond. Particularly in the present invention, a method of mixing the resin fine powder and the toner by mechanical shearing force or shaking is preferable. To mix such toner and the resin fine powder, a stirrer mixer, an airflow stirrer mixer, a high-speed flow mixer, a V-shaped mixer, a conical screw mixer, a double-cone mixer, a ball mill, Turbula mixer (trade name) can be used. Particularly, in the present invention, it is preferable to use a high-speed fluid type mixer having a high-speed stirring blade inside and mixing the toner and the resin fine powder by a shearing force, or a turbula mixer.

The toner used in the present invention has an average particle size of 5
It is possible to use toner of 30 μm or less in the range of μm or more.

The toner is mainly composed of a thermoplastic resin and a colorant, and a material known as a toner material can be used as the constituent raw material. Examples of the thermoplastic resin used as the binder resin in the present invention include vinyl resins such as styrene resin, acrylic resin, styrene-acrylic copolymer resin, and styrene-butadiene copolymer resin, or polyester resin, epoxy resin, polyamide resin, Examples thereof include polyurethane, polycarbonate, fluorine resin, silicone resin, phenol resin, maleic acid resin, coumarone resin and the like.

Among the resins, particularly in the present invention, the charging polarity,
It is preferable to use a polyester resin which is excellent as a binder resin for toner in terms of charging characteristics such as charging stability. The polyester resin is composed of dicarboxylic acids, diols and phenols that are polycondensed with these dicarboxylic acids as constituent raw materials, and if necessary, these constituent raw materials may be tricarboxylic acid, tetracarboxylic acid, polycarboxylic acid, carboxylic acid. It is produced by adding a polyvalent carboxylic acid such as a copolymer, a polyhydric alcohol such as triol, tetraol and polyol, or an isocyanate compound to form a crosslinked structure in the resin.

Examples of the dicarboxylic acid include maleic acid, citraconic acid, itaconic acid, fumaric acid, mesaconic acid, glutaconic acid (unsaturated aliphatic dicarboxylic acid), oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid,
Pimelic acid, suberic acid, azelaic acid, sebacic acid,
Cyclohexanedicarboxylic acid (saturated dicarboxylic acid), phthalic acid, isophthalic acid, terephthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid (aromatic dicarboxylic acid), and their acid anhydrides and lower alkyl esters Etc.

Examples of the diol which is polycondensed with the above-mentioned dicarboxylic acid to produce polyester include ethylene glycol, diethylene glycol, triethylene glycol,
1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, trimethylene glycol, 1,4-butanediol, 1,4-butenediol, 1,5-pentanediol, neopentyl glycol, 1,6 -Hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,10-decanediol, pinacol, hydrobenzoin, benzvinacol, cyclopentane-1,2-diol, cyclohexane-1,2-diol , Cyclohexane-1,4-
Examples thereof include diol and 1,4-bis (hydroxymethyl) cyclohexane.

Examples of tricarboxylic acids include tricarballylic acid, 1,2,3-butanetricarboxylic acid, 1,
2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 2,
Examples thereof include 5,7-naphthalene tricarboxylic acid, 1,2,4-naphthalene tricarboxylic acid, and their acid anhydrides and lower alkyl esters.

Examples of triols include glycerin, 1,2,4-butanetriol, 1,2,5-pentanetriol, 2-methylpropanetriol, 2
-Methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane and the like can be mentioned.

Examples of phenols include catechol, resorcinol, hydroquinone, pyrogallol, phloroglucinol, 1,2,4-benzenetriol,
1,3,5-trihydroxymethylbenzene, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropyleneated bisphenol A and the like can be mentioned.

Further, in the present invention, the above polyester binder resins may be used alone or in admixture of two or more, or may be used in the form of block or graft copolymerization of two or more. In addition, the above polyester resin is mixed with other resin,
Block copolymer or graft copolymer may be used. Examples of the binder resin include vinyl resins such as styrene resin, acrylic resin, styrene-acrylic copolymer resin, styrene-butadiene copolymer resin, epoxy resin, polyamide resin, polyurethane, polycarbonate, fluorine resin, and silicone resin. Examples thereof include resins, phenol resins, maleic acid resins, coumarone resins and the like.

Particularly in the present invention, terephthalic acid, 1, 2, 4
-A polyester resin composed of benzenetricarboxylic acid, polyoxyethylenated bisphenol A, or polyoxypropyleneized bisphenol A, and an oxyalkylene ether of a novolak type phenol resin obtained by adding an alkylene oxide to a novolak type phenol resin as a trunk polymer. It is preferable to use polyester resins EX-102 and EX-103 manufactured by Sanyo Kasei Co., Ltd. in which the polyester resin composed of polycarboxylic acid and polyol is graft-copolymerized with the polymer.

Further, in the present invention, it is preferable that the addition of the above-mentioned fluorine-based resin fine powder to the toner and the addition of the inorganic fine powder to the toner are used together. By using the addition of the fluorine-based resin fine powder to the toner and the addition of the inorganic fine powder to the toner in combination, the effect of sufficiently reducing fogging and the effect of improving resolution by the resin fine powder Alternatively, a reduction effect of fog generation potential on the low voltage side, an effect of expanding the photoconductor charging potential range in which fog is sufficiently reduced by reducing the fog on the high voltage side,
And a sufficient fogging reduction effect and resolution improvement effect over a wide range of developing conditions that facilitate the design of the developing device, or with respect to changes over time of a developing device including a developer and a photoreceptor associated with repeated development. It can be obtained more significantly.

The particle size of the inorganic fine powder is 0.00
1 to 2 μm, preferably 0.002 to 0.2 μm, and there is no problem even if they aggregate to form secondary particles. The inorganic fine powder is 0.1 to 0.1% with respect to the toner.
It can be added to the toner in the range of 5% by weight, particularly preferably in the range of 0.1 to 1% by weight.

The inorganic fine powder used in the present invention is preferably a metal oxide fine powder, and examples of such metal oxide fine powder include silica, tin oxide, aluminum oxide, titanium dioxide, zinc oxide, and these. The surface-treated product of the present invention may be mentioned, but particularly in the present invention, so-called dry process silica produced by vapor phase oxidation of a silicon halogen compound,
Alternatively, fine silica powder called colloidal silica is preferable. Further, it is preferable to use hydrophobic silica in which silica which is hydrophilic as it is is surface-treated with a known hydrophobizing agent. Examples of such silica include silica fine powder and a silane coupling agent such as dimethyldichlorosilane, hexamethyldisilazane, and trimethylsilane, or isopropyltriisostearoyl titanate, isopropyltridodecylbenzenesulfonyl titanate, and tetraisopropylbis (dioctyl). (Phosphate) titanate and other titanium coupling agents are used to replace the silanol groups on the surface of the silica fine powder with organic groups,
Hydrophobicized hydrophobic silica can be used.

The method of adding the inorganic fine powder to the toner is the same as the method of adding the fluorine-based resin fine powder to the toner, that is, simple mixing of the inorganic fine powder and the toner and mechanical shearing force are used. Adhesion of the fine powder to the surface of the toner used,
A physical method such as immobilization, immobilization of the fine powder on the toner surface by combined use of mixing and heat treatment, or immobilization of the fine powder on the toner surface by combined use of mixing and mechanical impact, or the toner and the Chemical methods such as immobilization by covalent bonding between fine powders or chemical bonding such as hydrogen bonding may be used.
Particularly in the present invention, a method of mixing the inorganic fine powder and the toner by mechanical shearing force or shaking is preferable. The method of adding the inorganic fine powder to such a toner includes a stirring type mixer, an air flow stirring type mixer, a high-speed flow type mixer, a V type mixer, a conical screw mixer, and a double cone type mixer. , Ball mill, Turbula mixer (trade name), etc. can be used. Particularly, in the present invention, it is preferable to use a high-speed fluid mixer or a turbula mixer which has a high-speed stirring blade inside and adds the inorganic fine powder to the toner by shearing force.

The inorganic fine powder may be added to the toner at the same time as the addition of the fluorine-based resin fine powder or before and after the addition.

On the other hand, known colorants can be used as the colorant used in the toner, and examples thereof include carbon black, iron black, ultramarine blue, aniline blue, phthalocyanine blue, phthalocyanine green, chalco oil blue, chrome yellow and quinacdrine. Indren blue,
Peacock blue, permanent red, lake red, rhodamine lake, Hansa yellow, permanent yellow, benzidine yellow, rose bengal and the like are used. The addition amount of these colorants is used in a wide range, but is usually 1 to 2 with respect to 100 parts by weight of the binder resin.
It is contained in the toner particles in an amount of 0 part by weight.

If desired, a well-known low molecular weight polyolefin wax may be contained in the toner particles for the purpose of preventing offset. Examples of such low molecular weight polyolefin wax include paraffin, chlorinated paraffin, polyethylene, chlorinated polyethylene, polyethylene oxide, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, Ethylene-methacrylic acid copolymer, ethylene-methacrylic acid ester copolymer, ethylene-vinyl chloride copolymer, ethylene-butene copolymer, ethylene-
Pentene copolymer, polypropylene, polypropylene oxide, ethylene-propylene copolymer, propylene-butene copolymer, propylene-pentene copolymer, ethylene-propylene-butene copolymer, ethylene-3-methyl-1-butene copolymer Examples thereof include polymers, olefin homopolymers such as polyisobutylene, and copolymers. These low molecular weight polyolefin waxes may be used alone or as a mixture in the toner. The polyolefin wax is used in a wide range, but it is usually contained in the toner in an amount of 0.3 to 5 parts by weight based on the binder resin.

If necessary, a charge control agent may be contained in the toner particles for the purpose of generating charges in the toner or stabilizing the charging of the toner. Examples of such a charge control agent used in the present invention include metal complex salts of azo dyes, chlorinated polyolefins, chlorinated polyesters, sulfonylamines of copper phthalocyanine, oil blacks, metal salts of naphthenic acids, and metal salts of fatty acids.

Further, the toner has fluidity, development and transferability, storage stability, prevention of filming of the toner on the surface of the photoreceptor,
Well-known external additives other than the inorganic fine powder may be added for the purpose of imparting the cleaning property. Examples of such external additives include long-chain fatty acids such as stearic acid and esters thereof, amides, metal salts, carbon black, graphite, fluorinated graphite, polycyclic aromatic compounds and the like. These external additives may be added at the same time as the addition of the fluororesin fine powder of the present invention to the toner and the addition of the inorganic fine powder to the toner, or before or after these additions.

The method for producing the developer according to the present invention will be described below. The toner according to the present invention can be produced by a known method, in which a binder resin, a colorant, a low molecular weight polyolefin wax, a charge control agent are premixed, and then a roll,
A kneaded product is obtained by kneading and dispersing with a Banbury mixer, an extruder, a kneader or the like. After cooling the kneaded product, it is roughly pulverized to 1 mm or less by a hammer mill or the like, then finely pulverized by a jet mill and further classified by an air stream classifier to obtain a toner having an average particle size of 5 to 30 μm. Further, if necessary, the inorganic fine powder is added to the toner by using a high-speed flow type mixer, and at the same time as the addition, or before or after the addition, the fluorine-based resin fine powder using the apparatus is added. The developer of the present invention is obtained by adding the toner to the toner.

The fog produced by the developer according to the present invention is
Develop a white solid image where the entire surface of the photoconductor is the non-image area,
Measure the fog density of the photoreceptor to which the developer is electrostatically adhered or the white solid image is transferred and fixed on an image support such as paper after development and the fog density of the support to which the developer is adhered It can be evaluated by doing. In order to measure the fogging density of the photoconductor to which the developer is attached, the white solid image is developed under specific development conditions, and the process is interrupted during the development process. Next, a transparent portion having adhesiveness is applied to a portion of the photoreceptor after development, which is originally to be transferred to an image support such as paper, that is, a portion between the developing position of the electrostatic latent image and the transfer position to the support. A transfer body such as a tape is attached, and the developer adhering to the photosensitive body is transferred to the transfer body with a physicochemical adhesive force. The fogging density was measured by measuring the optical reflection density of the sample by sticking the transfer body, to which the developer was transferred, onto a support such as paper, and then measuring the optical reflection density of the sample as a blank density from the density of the transfer body and the support. It is obtained by subtracting the dynamic reflection density and obtaining the density of only the developer.

On the other hand, in order to measure the fog density on the image support to which the developer is attached, the white solid image is developed, transferred and fixed under a specific developing condition, and the non-image area is developed with the developer. The support on which is fixed is used as a sample. The fog density can be obtained by subtracting the reflection density of only the support from the optical reflection density of the sample to obtain the density of only the developer.

The developing conditions used in the present invention include brush charging, scorotron charging, roller charging, and other charging methods for photoconductors, photoconductor charging potentials, and developers that have changed over time due to repeated development, and photoconductors. Examples include the use of a developing device.

A clear image with reduced fog that can be used in the present invention means that the fog density on the photoreceptor is 0.02 or less, or the fog density on the image support is 0.01 or less. When a black solid image is developed, the image density of the solid black portion after fixing on the image support is 1.
The image is 30 or more.

The range of development conditions for obtaining the above image is determined from the above charging method and the change in fog density of a white solid image with respect to the potential obtained by arbitrarily changing the photoconductor charging potential within the practical range of the potential. . The range of the developing conditions is an arbitrary charging method, and a fog density of 0.02 or less in the charging method is set as an allowable value, and a maximum photoconductor potential and a minimum photoconductor potential at which the fog density less than the allowable value is obtained. The magnitude of the absolute value of the difference, that is, the combination of the magnitude of the absolute value of the difference between the high-pressure side fog occurrence potential and the low-pressure side fog occurrence potential that gives a fog density greater than 0.02. . In addition, by measuring the optical reflection density of a black solid image developed at the photoconductor charging potential within the range of the high-voltage side fog generation potential and the low-voltage side fog generation potential, it is possible to obtain a sufficient image density within the potential range. It can be confirmed that it can be obtained.

Similarly, the change in the fog density of a white solid image with respect to the above-mentioned arbitrary photoconductor potential at the time of initial development using a developing device containing an unused developer and a photoconductor, and the fog density after repeated development. From the change, the range of the developing condition for obtaining the above-mentioned image when the developing condition accompanying the repeated development and the changing condition of the developing device with time are the developing conditions is shown. Similarly, from the optical reflection density of the black solid image developed at the photoconductor charging potential within the range of the high-pressure side fog generation potential and the low-pressure side fog generation potential at the initial development and the density after repeated development, It can be confirmed that an image having a high density can be obtained with respect to changes with time of a developing device including a developer and a photoconductor that accompany repeated development.

[0059]

EXAMPLES The present invention will be specifically described below with reference to production examples, examples and comparative examples, but the present invention is not limited to these examples. In addition, the middle part of the following examples shows the weight part with respect to the binder resin.

(Production Example 1) Binder resin (polyester resin EX-103 manufactured by Sanyo Kasei Co., Ltd.) ... 100 parts Carbon black (MA-100 manufactured by Mitsubishi Kasei Co., Ltd.)・ ・ ・ ・ ・ ・ ・ 9 parts Charge control agent (T-77 manufactured by Hodogaya Chemical Co., Ltd.) ・ ・ ・ ・ 2 parts Low molecular weight polypropylene (Viscor 550P manufactured by Sanyo Chemical Co., Ltd.) ・······································································ Off of each of the constituent raw materials is preliminarily mixed, and then continuously kneaded with a kneader heated to 150 ° C. After cooling the obtained lumps to room temperature, they are roughly crushed to about 1 mm * 1 mm with a cutter mill, finely crushed with a jet mill, and then classified with an air stream classifier to obtain toner having a weight average particle size of 10 μm. did.

(Production Example 2) A binder resin was used as a styrene-acrylic copolymer resin (TBH150 manufactured by Sanyo Kasei Co., Ltd.).
0), charge control agent TRH manufactured by Hodogaya Chemical Co., Ltd.,
A toner was manufactured in the same manner as in Manufacturing Example 1 except that the weight average particle diameter was 9 μm.

Example 1 A high-speed flow type mixer was used for the toner obtained in Production Example 1, and 0.4% by weight of the toner was used.
Ratio of hydrophobic silica (R97 manufactured by Nippon Aerosil Co., Ltd.
After the addition of 2) to the toner was performed, 1.3
A polytetrafluoroethylene fine powder having a weight average particle diameter of 5.5 μm and a fine powder content of 22 μ% or less having a weight average particle diameter of 3 μm or less was added at a ratio of wt% to obtain a developer.

A commercially available PC-PR1000 printer (NE, in which this developer is charged by scorotron charging as a photoreceptor charging method and a toner cartridge using a titanyl phthalocyanine photoreceptor as a photoreceptor is installed, and a hot roll fixing device is mounted.
(Manufactured by Company C), changes in fog density with respect to photosensitive belt charging potential at initial development, image density, and changes in fog density with respect to photosensitive belt charging potential after running 5000 sheets, and image density were examined. The photoconductor charging potential was controlled by an external high voltage power source by insulating the scorotron charger from the printer.

For measuring the fog density, the fog density on the photoconductor by the photoconductor to which the developer was attached was used. The fog density was measured by measuring the optical reflection density at any 5 points of the sample with a Macbeth densitometer after transferring the transfer material obtained by transferring the developer from the photoconductor to a sample, and transferring it as a blank density from the density. It was obtained by averaging the fog densities obtained by subtracting the optical reflection densities of the body and the support only. At the time of initial development and after running 5000 sheets, the obtained fog density is plotted against the electrified electric potential of the photoconductor, and the fog density becomes higher than 0.02. The high-side fog generation potential, the low-side fog generation potential, and the fog The absolute value of the difference between the high-voltage side fog-generated potential and the low-voltage side fog-generated potential was determined as the size of the potential range in which the fog was sufficiently reduced.

Regarding the image density, a solid black image was developed using a Macbeth densitometer during initial development and after running 5000 sheets, and a solid black image was developed within the range of the photoconductor charging potential at which the fog density was sufficiently reduced. It was obtained by measuring arbitrary 5 points on the image and obtaining the average value of all the obtained optical reflection densities.

Next, a developer similar to the above-described developer is charged into the toner cartridge by brush charging, and a toner cartridge using a titanyl phthalocyanine photoreceptor is filled in the photoreceptor, and a commercially available PC equipped with a hot roll fixing device is loaded. -PR1000E
/ 4 printer (manufactured by NEC Corporation), similarly to the above, changes in fog density with respect to photosensitive belt charging potential at initial development, and image density, and changes in fog density with respect to photosensitive belt charging potential after running 5000 sheets, Also, the image density was examined.

The results are shown in Table 1 below together with the following examples and comparative examples. As shown in the table, when the above-mentioned developers are used, fogging is sufficiently reduced, a clear image having excellent resolution and high image density is obtained, the developing conditions for obtaining the image are wide, and repeated development is performed. It was shown that a clear image can be obtained even with the change with time of the developing device including the developer and the photoconductor.

Example 2 Example 1 was repeated except that toner and hydrophobic silica were added and polytetrafluoroethylene fine powder was added at the same time to make the proportion of the polytetrafluoroethylene fine powder 2% by weight. A developer was prepared in the same manner as in.

This developer was filled in two types of toner cartridges in the same manner as in Example 1, and a PC-PR1000 printer and a PC-PR1000E / 4 printer were used to change the fog density with respect to the photosensitive belt charging potential at the initial development. , And the image density, and the change in the fog density with respect to the charging potential of the photosensitive belt after running 5000 sheets, and
The image density was examined.

As shown in Table 1, when the above-mentioned developer is used, fog is sufficiently reduced, a clear image having excellent resolution and high image density is obtained, and the developing conditions for obtaining the image are wide. It has been shown that a clear image can be obtained even with a change with time of a developing device including a developer and a photoconductor due to repeated development.

Example 3 A high-speed flow type mixer was used for the toner obtained in Production Example 2, and 0.4% by weight of the toner was used.
Ratio of hydrophobic silica (R97 manufactured by Nippon Aerosil Co., Ltd.
At the same time as the addition of 2) to the toner, a tetrafluoroethylene-perfluoroalkyl ether copolymerization having a weight average particle diameter of 6 μm and a fine powder content of 3 μm or less of 18 wt% at a ratio of 1.5% by weight to the toner Fine powder of coalescence was added to obtain a developer.

This developer was filled in two types of toner cartridges in the same manner as in Example 1, and a PC-PR1000 printer and a PC-PR1000E / 4 printer were used to change the fog density with respect to the charging potential of the photosensitive belt at the time of initial development. , And the image density, and the change in the fog density with respect to the charging potential of the photosensitive belt after running 5000 sheets, and
The image density was examined.

As shown in Table 1, when the above developer is used, fogging is sufficiently reduced, a clear image having excellent resolution and high image density is obtained, and the developing conditions for obtaining the image are wide. It has been shown that a clear image can be obtained even with a change with time of a developing device including a developer and a photoconductor due to repeated development.

Example 4 A developer was prepared in the same manner as in Example 1 except that the amount of hydrophobic silica added was 0% by weight.

This developer was filled in two kinds of toner cartridges in the same manner as in Example 1, and a PC-PR1000 printer and a PC-PR1000E / 4 printer were used to change the fog density with respect to the photosensitive zone charging potential at the initial development. , And the image density, and the change in the fog density with respect to the charging potential of the photosensitive belt after running 5000 sheets, and
The image density was examined.

As shown in Table 1, when the above developer is used, fogging is sufficiently reduced, a clear image having excellent resolution and high image density is obtained, and the developing conditions for obtaining the image are wide. It has been shown that a clear image can be obtained even with a change with time of a developing device including a developer and a photoconductor due to repeated development.

(Comparative Example 1) Hydrophobic silica (R972 manufactured by Nippon Aerosil Co., Ltd.) was used in the toner obtained in Production Example 1 in a high-speed flow type mixer at a ratio of 0.4% by weight to the toner.
Was added as a developer.

This developer was filled in two kinds of toner cartridges as in Example 1, and a PC-PR1000 printer and a PC-PR1000E / 4 printer were used to change the fog density with respect to the photosensitive zone charging potential at the time of initial development. , And the image density, and the change in the fog density with respect to the charging potential of the photosensitive belt after running 5000 sheets, and
The image density was examined.

As shown in Table 1, when the above-mentioned developer was used, scorotron charging resulted in an image having a low density although there was a photoconductor potential capable of sufficiently reducing fogging. On the other hand, with brush charging, there was no photoconductor potential sufficient to reduce fogging, and only low density images were obtained.

(Comparative Example 2) Polytetrafluoroethylene fine powder having a weight average particle diameter of 3.9 μm and a fine powder amount of 3 μm or less is 33% by weight, and the addition amount to the toner is 1.
A developer was manufactured in the same manner as in Example 2 except that the amount was 3% by weight.

This developer was filled in two types of toner cartridges in the same manner as in Example 1, and the fog density was changed with respect to the photosensitive zone charging potential at the time of initial development by using a PC-PR1000 printer and a PC-PR1000E / 4 printer, respectively. , And the image density, and the change in the fog density with respect to the charging potential of the photosensitive belt after running 5000 sheets, and
The image density was examined.

As shown in Table 1, when the above developer was used, a high image density was obtained by both scorotron charging and brush charging, but there was no photoconductor potential sufficient to reduce fogging.

(Comparative Example 3) The addition amount to the toner was 13
A developer was manufactured in the same manner as in Example 2 except that the content was changed to% by weight.

This developer was filled in two types of toner cartridges in the same manner as in Example 1, and a PC-PR1000 printer and a PC-PR1000E / 4 printer were used to change the fog density with respect to the photosensitive zone charging potential at the time of initial development. , And the image density, and the change in the fog density with respect to the charging potential of the photosensitive belt after running 5000 sheets, and
The image density was examined.

As shown in Table 1, when the above-mentioned developer was used, a high image density could be obtained by both scorotron charging and brush charging, but the photoconductor potential at which fogging was sufficiently reduced was narrow. In addition, the image after fixing has defective fixing.

Comparative Example 4 The same procedure as in Example 2 was repeated except that polytetrafluoroethylene fine powder was used as polyvinylidene fluoride having a weight average particle diameter of 5 μm and the addition amount to the toner was 1.3% by weight. Manufactured.

This developer was filled in two kinds of toner cartridges in the same manner as in Example 1, and the fog density was changed with respect to the photosensitive belt charging potential at the time of initial development by using a PC-PR1000 printer and a PC-PR1000E / 4 printer, respectively. , And the image density were examined.

As shown in Table 1, in the case of using the above-mentioned developer, there is no photoconductor potential capable of sufficiently reducing fogging by both scorotron charging and brush charging, and only an image having an extremely low density is obtained. I couldn't do it.

(Comparative Example 5) Polytetrafluoroethylene fine powder was polyethylene with a weight average particle diameter of 4 μm, and the addition amount to the toner was 4% by weight.
A developer was prepared in the same manner as in.

This developer was filled in two kinds of toner cartridges in the same manner as in Example 1, and the fog density was changed with respect to the charging potential of the photosensitive belt at the time of initial development by using a PC-PR1000 printer and a PC-PR1000E / 4 printer, respectively. , And the image density were examined.

As shown in Table 1, when the above-mentioned developer is used, there is no photoconductor potential which can sufficiently reduce fogging by both scorotron charging and brush charging, and only an image having an extremely low density can be obtained. I couldn't do it.

[0092]

[Table 1]

[0093]

The non-magnetic one-component developer of the present invention has various excellent effects. That is, in the conventionally known developer,
For any charging method, there is no photoconductor charging potential that can provide a clear image with reduced fog that can be put to practical use, or low-pressure side fog occurs up to a high potential, and in order to obtain the image, There is a problem that a high potential is required, or fogging occurs on the high voltage side due to a low potential in addition to the fog on the low voltage side, and the development conditions for obtaining a clear image without fog are extremely narrow. However, the non-magnetic one-component developer provided by the present invention does not have such a problem, and the developer with a wide range of developing conditions, or the developer accompanying repeated development,
Further, fogging is sufficiently reduced even with respect to a change with time of a developing device including a photoconductor, and a clear image having excellent resolution and high image density is provided.

[Brief description of drawings]

FIG. 1 is an example of a change in fog density on a photoconductor with respect to the potential when the photoconductor charging potential is arbitrarily changed within a practical range of the potential.

[Explanation of symbols]

1 Fog generation potential on low voltage side 2 Fog is sufficiently reduced and clear image can be obtained Allowable value of fog density on photoreceptor 3 High potential fog potential 4 Low potential fog region 5 Fog is sufficiently reduced , Potential region where clear image is obtained 6 Potential region where fog on the high voltage side occurs

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[Procedure amendment]

[Submission date] July 20, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction content]

The fluororesin used in the present invention includes:
Polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-ethylene copolymer Polymer, polychlorotrifluoroethylene, chlorotrifluoroethylene- ethylene
And copolymers thereof, and the like. Particularly, in the present invention, it is preferable to use polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl ether copolymer, or tetrafluoroethylene-hexafluoropropylene copolymer as the fluorine-based resin. Further, the effect of the present invention is that the molecular weight of the fluororesin fine powder,
The characteristics of the fine powder such as molecular weight distribution, crystallinity and melting point are not limited.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location 372 375

Claims (6)

[Claims] 1. A toner having a thermoplastic binder resin and a colorant as main components, and having a weight average particle diameter of 0.1 to 10% by weight, the weight average particle diameter being equal to or smaller than the weight average particle diameter of the toner, Diameter 3μ
A method for producing a non-magnetic one-component developer, which comprises adding a fluororesin fine powder having a fine powder content of m or less of 30% by weight or less. 2. The method for producing a non-magnetic one-component developer according to claim 1, wherein the thermoplastic binder resin is a polyester resin. 3. The method for producing a non-magnetic one-component developer according to claim 1, wherein the fluororesin fine powder is polytetrafluoroethylene fine powder. 4. The weight average particle diameter of the fluorinated resin fine powder is from 4 to 4.
The method for producing a non-magnetic one-component developer according to claim 1, wherein the non-magnetic one-component developer has a thickness of 20 μm. 5. At the same time as the addition of the fluorine-based resin fine powder to the toner, or after the addition of the resin fine powder, the toner of the toner of 0.
The method for producing a non-magnetic one-component developer according to claim 1, wherein the inorganic fine powder is added in a proportion of 1 to 5% by weight. 6. The method for producing a non-magnetic one-component developer according to claim 5, wherein the inorganic fine powder is colloidal silica surface-treated with a hydrophobizing agent.