JP2003162091A - Method for manufacturing nonmagnetic monocomponent developer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a nonmagnetic monocomponent developer having both excellent anti-offsetting property and excellent resistance to fusion bonding to a blade and also having improved durability in repetitive use. <P>SOLUTION: In the method for manufacturing a nonmagnetic monocomponent developer in which at least a binder resin, a colorant and a release agent are mixed, kneaded, comminuted and classified, the binder resin comprises a polyester resin consisting of polycarboxylic acid components including aromatic dicarboxylic acids and aromatic tricarboxylic acids and polyol components including aromatic diols, at least part of which are polyoxyethylenated bisphenols, and having 100-140°C softening point, the release agent is an ester wax having an endothermic peak measured with a differential scanning calorimeter (DSC) at 50-90°C and the kneading is carried out with a two-shaft screw extruder having a plurality of temperature controllable cylinder blocks and two screws rotatable in the same direction. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a non-magnetic one-component developer, and more particularly to a method for producing a non-magnetic one-component developer used in electrophotographic copying machines and electrostatic recording devices. More specifically, the present invention relates to a method for producing a non-magnetic one-component developer having both excellent fixing property and excellent blade fusion resistance, and excellent durability.

[0002]

2. Description of the Related Art As a developing method used in a copying machine or an electrostatic recording apparatus, a developer is conveyed by a conveying member, and the electrostatic latent image formed on a photoreceptor by the conveyed developer is visualized. The method of converting into a known substance is well known. With this development method,
Generally, a one-component developer composed of only toner or a two-component developer composed of toner and carrier is used.

In recent years, various types of development using a one-component developer (hereinafter also referred to as a one-component developer) consisting of toner alone have the advantage that the apparatus can be downsized and maintenance is easy. A scheme has been proposed and used. Although there are non-magnetic and magnetic one-component developers, vigorous development of non-magnetic ones is in progress due to compatibility with color printers.

Development using a non-magnetic one-component developer (hereinafter also referred to as non-magnetic toner) is carried out, for example, using a developing device having the following structure. That is, a toner transport member (developing roller) and a toner replenishing auxiliary member (supply roller) are provided in pressure contact with the photosensitive drum in a toner container installed near the electrostatic latent image holder (photosensitive drum). Therefore, the developing bias voltage is applied to the toner conveying member from the power source. Further, a non-magnetic toner is contained in the toner container and is conveyed to the contact surface between the toner replenishment auxiliary member and the toner conveying member. Here, the particles of the non-magnetic toner are regulated to have an appropriate layer thickness by a toner layer thickness regulating member (charging blade) and are charged, and move onto the toner conveying member to form a thin layer on the surface thereof. The non-magnetic toner is carried to the latent image holding member side as the toner conveying member rotates, comes into contact with the surface of the latent image holding member, and moves onto the latent image holding member corresponding to the electrostatic latent image formed there. The electrostatic latent image is thereby developed. The image formed of the non-magnetic toner formed on the latent image holding member is electrostatically transferred onto a transfer target material such as paper in a transfer section including a transfer roller,
Subsequently, it is heated and fixed on the material to be transferred in a fixing unit including a fixing roller and the like.

At the fixing portion, there is a phenomenon in which the non-magnetic toner on the transfer material migrates and adheres to the fixing roller, which is called an offset phenomenon. As a method for avoiding the offset phenomenon, it is common to supply a releasing agent such as silicone oil onto the fixing roller, and it is widely practiced. However, the supply of the release agent onto the fixing roller has a problem that the surface of the fixing roller is contaminated by the release agent or its decomposed product, as well as the technical difficulties associated with the constant supply.

Therefore, a fixing method (hereinafter also referred to as oilless fixing) in which the release agent is not supplied onto the fixing roller has been desired, and technical development has been made. As a typical method for oilless fixing, a method has been proposed in which a release agent is contained in the non-magnetic toner itself.

[0007]

The method of incorporating a releasing agent into a non-magnetic toner, which has been proposed for oilless fixing, is an effective method, but it also has problems. That is, for this purpose, waxes having a melting point lower than that of the non-magnetic toner itself are usually used, but it is necessary to contain a considerably large amount of waxes in order to realize oilless fixing. However, the dispersed diameter of the wax in the resin varies depending on the type of the resin and wax constituting the non-magnetic toner, and when the wax is excessively dispersed and has a small particle size, the obtained toner has a large adhesive force. The fluidity is poor, and the toner consumption is likely to be deteriorated by causing a decrease in charge with repeated use. On the other hand, when the wax is insufficiently dispersed and the dispersed particle size is excessively large, the wax particles are likely to be detached from the surface and the wax particles are apt to be fused to the developing roller, the charging blade and the photosensitive drum.

In particular, in the contact portion between the developing roller portion and the charging blade, the non-magnetic toner is retained under pressure and heat due to friction, but it is contained for improving the fixability (low temperature fixability). If the amount of waxes to be applied is large, a phenomenon of aggregation and fusion of the toner to the charging blade (hereinafter, also referred to as blade fusion) is likely to occur. When blade fusion occurs, the non-magnetic toner cannot move onto the developing roller at the location where the blade fusion occurs, and development cannot be performed. As a result, image defects called white lines are caused. These problems have been pointed out as serious problems particularly in full-color toners that are developed using a plurality of color toners such as cyan, magenta, yellow, and black. Therefore, it is no exaggeration to say that the durability as a toner depends on the optimum dispersed particle diameter of the wax, but conventionally, sufficient information has been disclosed regarding the combination of the resin and the wax used. I can't say that

As described above, in the non-magnetic toner containing waxes for oilless fixing, the fixing property (low temperature fixing property, anti-offset property) and the blade fusion resistance property are contradictory to each other. It has been strongly desired to combine the above-mentioned properties and to improve the durability during repeated use and continuous use. These problems eventually result in what kind of characteristics (thermal characteristics such as Tg and viscoelastic characteristics such as elasticity) and the wax are used in combination.

The object of the present invention is to provide a method for producing a non-magnetic one-component developer which has both excellent fixability and excellent blade fusion resistance and has improved durability during repeated use and continuous use. Is to provide.

[0011]

As a result of intensive studies to solve the above-mentioned problems, the present inventors have identified a non-magnetic one-component developer in which a specific binder resin and a release agent are combined as a specific method. The present invention has been completed by finding out that the above problems can be solved by manufacturing the present invention. That is, the gist of the present invention is a method for producing a non-magnetic one-component developer comprising mixing at least a binder resin, a colorant and a release agent, kneading, pulverizing, and classifying the binder resin,
A softening point 100 to 140 comprising a polyvalent carboxylic acid component containing an aromatic dicarboxylic acid and an aromatic tricarboxylic acid and a polyhydric alcohol component containing an aromatic diol, at least a part of which is a polyoxyethylenated bisphenol. Containing a polyester resin of ° C, and
The releasing agent is an ester wax having an endothermic peak measured by a differential scanning calorimeter (DSC) at 50 to 90 ° C., and kneading has a plurality of temperature-adjustable cylinder blocks and two screws that can rotate in the same direction. It is carried out by an axial screw extruder, and the screw is composed of at least a transportation section, one or more kneading sections, and an extrusion section, and the temperature setting of the cylinder block corresponding to the transportation section of the screw is set to 20 from the endothermic peak temperature of the release agent. Cylinder block corresponding to the kneading part of the screw is set at 20 ° C or more higher than the endothermic peak temperature of the release agent and 10 ° C or more lower than the softening point of the binder resin, corresponding to the extruding part of the screw. A non-magnetic one-component developer characterized in that the cylinder block is set at 20 ° C. or more higher than the softening point of the binder resin. Production method, consists in.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. The non-magnetic one-component developer of the present invention contains a binder resin, a colorant, and a releasing agent as essential components, but may optionally contain a charge control agent, various fine particles, other additives and the like.

As the binder resin, a binder resin containing a polyvalent carboxylic acid component containing an aromatic dicarboxylic acid and an aromatic tricarboxylic acid and a polyhydric alcohol component containing an aromatic diol as an essential component is used. . Although other known resins suitable for developers can be used in combination, the proportion of the above polyester resin in the binder resin is at least 50% by weight, preferably 70% by weight or more, more preferably 85% by weight or more. .

Examples of other resins that can be used in combination include other saturated polyester resins, unsaturated polyester resins, styrene resins, and epoxy resins. Examples of the aromatic dicarboxylic acid serving as the polycarboxylic acid component of the polyester resin used as the essential component include, for example, terephthalic acid, isophthalic acid, phthalic acid, diphenic acid, naphthalenedicarboxylic acid, and the like, or methyl ester of these acids, and ethyl. Examples thereof include lower alkyl esters such as esters (having about 1 to 4 carbon atoms in the alkyl group). Above all, it is desirable to select terephthalic acid because a resin having a high rigidity and a high Tg can be obtained and the generation of streaks can be suppressed. At least 50 mol% or more of all polyvalent carboxylic acid components is terephthalic acid. Is preferred. Similarly, examples of the aromatic tricarboxylic acid serving as a polyvalent carboxylic acid component include trimellitic acid and naphthalene tricarboxylic acid. Above all, it is desirable to select trimellitic acid because a resin having a high Tg and a high elasticity due to cross-linking is obtained and the offset resistance is improved, and at least 0.1 to 10 mol of the polyvalent carboxylic acid component is contained. It is preferred that% is trimellitic acid. The trimellitic acid may be anhydride.

Further, a part of the polyvalent carboxylic acid component of the polyester resin, preferably 30 mol% or less, may be used in combination with another polyvalent carboxylic acid. Examples of such polyvalent carboxylic acids include adipic acid, sebacic acid, cyclohexanedicarboxylic acid, butanetricarboxylic acid, hexanetricarboxylic acid, octanetetracarboxylic acid and the like.

On the other hand, examples of the aromatic diol which is the polyhydric alcohol component of the polyester resin used as the above essential component include biphenyl-4,4'-diol,
Biphenyl-3,3'-diol, bisphenols such as bisphenol A; etherified bisphenols such as polyoxyethylenated bisphenol A and polyoxypropyleneized bisphenol A; and other bisphenol compounds, such as aromatic diol components. It is necessary to use polyoxyethylenated bisphenols as at least a part, and polyoxyethylenated bisphenol A is preferably used. Among the polyoxyethylenated bisphenols, polyoxyethylene (n) -2,2-bis (4-hydroxyphenyl) propane is preferable, and 2.1 ≦ n ≦ 2.5 is more preferable. Optimally, oxyethylene (n) -2,2-bis (4-hydroxyphenyl) propane is used as at least a part of the aromatic diol component. By using the above-mentioned polyoxyethylenated bisphenols, a resin having a high rigidity and a high Tg can be obtained, and the durability as a resin is improved, so that the occurrence of image streaks is suppressed. On the other hand, the use of this component may cause difficulty in pulverization at the time of toner production. Therefore, the amount used is preferably 5 to 60 mol% based on all carboxylic acid components. Part of the polyhydric alcohol component of the polyester resin, preferably 30
Other polyhydric alcohols may be used in combination at a mol% of not more than. Examples of such polyhydric alcohols include ethylene glycol, 1,2-propylene glycol,
Examples thereof include diols such as 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol and 1,4-butenediol, trimethylolethane, trimethylolpropane, glycerin, pentaerythritol and the like.

The thermal characteristics and molecular weight distribution of these binder resins are generally adjusted so as to suit the developing device and fixing system, but considering the application to full-color toner, the softening point by the flow tester 1/2 method is 100 to 100. It needs to be 140 ° C, and preferably 110 to 130 ° C.
Further, the glass transition point (Tg) by DSC method is 55 to 7
The temperature is preferably 5 ° C, more preferably 60 to 70 ° C. Further, the amount of the tetrahydrofuran (THF) -soluble component of the resin is preferably 80% or more, more preferably 90% or more of the whole resin. Moreover, regarding the molecular weight of the soluble component by gel permeation chromatography (GPC), the maximum peak molecular weight is 4000 to 10,000, the weight average molecular weight (Mw) is 30,000 to 200,000, and the number average molecular weight (Mn) is It is good that it is 4000-8000 and the ratio Mw / Mn is 4-30. Furthermore, in consideration of charging characteristics and humidity resistance, the acid value of the resin of the present invention is preferably 30 KOHmg / g or less when measured by the method of JIS-K0070 or a method equivalent thereto, more preferably 1 to 15 KOHmg. It is better to prepare it so that it becomes / g.

In the production of the polyester resin, the reaction temperature, the reaction pressure and the like may be determined according to the monomer composition (reactivity) according to a known method, and the reaction may be terminated when predetermined physical properties are obtained. Examples of the colorant include carbon black, lamp black, iron black, ultramarine blue, nigrosine dye, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa yellow G, rhodamine dyes and pigments, chrome yellow, quinacridone, benzidine yellow, rose bengal, tritium. Any known dyes and pigments such as allylmethane dyes, monoazo dyes and pigments, disazo dyes and pigments, condensed azo dyes and pigments can be used alone or in combination. Particularly in the case of a full-color developer, yellow is benzidine yellow, monoazo dyes and pigments, condensed azo dyes and pigments, magenta is quinacridone, rhodamine dyes and pigments, monoazo dyes and pigments, cyan is phthalocyanine blue, and black is carbon black. It is preferably used. The colorant is usually used in the range of 1 to 20 parts by weight, more preferably 3 to 10 parts by weight, based on 100 parts by weight of the binder resin. The colorant may be used as a masterbatch with the resin in advance.

The releasing agent is a differential scanning calorimeter (DS).
It is required to be an ester wax having an endothermic peak according to C) at 50 to 90 ° C. This is preferable because low-temperature fixability can be achieved, but among them, those having an endothermic peak at 60 to 90 ° C. are particularly preferable in view of heat resistance and storage stability of the obtained toner. The ester wax is a monovalent carboxylic acid having 18 or more carbon atoms and 18 carbon atoms.
The ester with the above monohydric alcohol is preferable. Examples of the monovalent carboxylic acid include stearic acid, arachidic acid, behenic acid, and lignoceric acid. Examples of the monovalent alcohol include stearyl alcohol, arachidyl alcohol (icosanol), and the like.
Examples thereof include behenyl alcohol (docosanol) and tetracosanol. Suitable ester waxes in the present invention include, for example, stearyl stearate, arachidyl arachidyl, behenyl behenate, and the like. Among them, behenyl behenate is particularly preferable. The release agent is usually used in an amount of 0.1 to 10 parts by weight, preferably 1 to 7 parts by weight, based on 100 parts by weight of the binder resin. If the amount added is less than the above range, it becomes difficult to obtain the effect of low-temperature fixability as a toner, and if it is used in excess of the above range, the fluidity of the obtained toner tends to deteriorate, so that a uniform layer is obtained. There is a possibility that the image cannot be formed and the image quality is deteriorated, such as a decrease in image density.

The endothermic peak temperature of the wax is measured by DSC (for example, DSC120 manufactured by Seiko Denshi KK) under the following conditions.

[0021]

[Table 1] Measurement temperature: 30 to 150 ° C. Temperature rising rate: 2 ° C./min Sample amount: 10 mg In addition to the above specific ester-based releasing agent, a relatively low temperature is mainly used for the purpose of improving fixability. Melting point paraffin wax, higher fatty acid, fatty acid amide, ketone wax, rice wax,
Carnauba wax, Fischer-Tropsch wax, and other low-melting-point waxes are used in a range that does not impair the effects of the above-mentioned specific ester wax, usually the above ester-based release agent 100.
You may add in 0.1-10 weight part with respect to weight part.

A small amount of various silicone oils, modified silicone oils, silicone varnishes and modified silicone varnishes commonly used as a release agent may be added. The ester wax according to the present invention is dispersed in the polyester resin according to the present invention, and the dispersed particle diameter thereof is preferably 1 to 2.5 μm in number average diameter, more preferably 1 to 2.5 μm in number average diameter. The thickness of 2 μm is preferable in terms of further improving durability. If the dispersed particle diameter of the ester wax is smaller than the above range, the excessive dispersion of the wax tends to cause a decrease in charge during repeated use of the toner. On the contrary, when the dispersed particle size exceeds the above range and the dispersed particle size is excessively large, the coarse wax particles are likely to cause the filming phenomenon on the developing roller or the photosensitive drum.
Further, when the wax according to the present invention is dispersed in the resin according to the present invention within the above range of dispersion diameter, a bad phenomenon such as blade fusion hardly occurs.

The wax dispersion diameter in the present invention is measured by a transmission electron microscope (TEM), and the measurement is performed as follows. That is, a sucrose aqueous solution is added to the toner particles and kneaded, a small amount thereof is put on the sample carrier head, and cooled with liquid nitrogen to prepare a frozen sample. Next, using an ultramicrotome whose cutting unit can be cooled with liquid nitrogen, the frozen sample is chamfered with a glass cutter and then cut with a diamond cutter to a thickness of 70 nm to prepare a sample. Further, the cut sample is placed on the collodion film-clad mesh and dyed with ruthenium tetroxide. Using this dyed sample, T
EM (Hitachi H-7500 system) 1 at 10,000 times magnification
Take a photographic image of 0 field or more. 300 or more wax particles are arbitrarily extracted from the obtained image, the Feret diameter in the horizontal direction is measured, and the average value is taken as the number average diameter. The calculation may be either an image analysis method or an actual measurement method using calipers.

In addition, in the present invention, a charge control agent may be used so that the toner has a positive polarity or a negative polarity depending on the purpose. Examples of the charge control agent in which the toner exhibits negative polarity include, for example, azo complex dyes containing metals such as Fe and Cr, copper phthalocyanine dyes, metal complexes of salicylic acid or its alkyl derivatives, metal salts, calixarene, organozirconium compounds, organic compounds. Examples thereof include boron compounds. Examples of the charge control agent in which the toner exhibits a positive polarity include a nigrosine dye, a phenylmethane dye containing a tertiary amine as a side chain, a quaternary ammonium salt compound, cetyltrimethylammonium bromide, a polyamine resin, and an imidazole derivative. To be The amount used is preferably in the range of 0.5 to 10 parts by weight with respect to 100 parts by weight of the binder resin. Among the above, in consideration of the charging characteristics of the polyester resin according to the present invention, it is preferable to use the toner as a negatively charged toner. It is better to select according to the suitability for toner to toner.

Further, if necessary, various inorganic fine particles such as magnetite, ferrite, cerium oxide, strontium titanate, barium titanate, talc, talcites, silicon nitride, silicon carbide, titanium nitride and silica are added. You can These inorganic fine particles have a hydrophobicity of 50.
The above is preferable. More preferably, it is 60 or more. The hydrophobizing agent may be used by chemically fixing it to the surface of the inorganic fine particles using a coupling agent or the like, or by merely physically fixing it. By adding the inorganic fine particles having a hydrophobicity of 50 or more, the charging characteristics of the charging blade are improved, the adhesion to the photosensitive drum is reduced, and the transfer efficiency is improved.

As the organic fine particles, resin fine particles made of styrene resin, acrylic resin, benzoguanamine resin, melamine resin, etc. can be added. The addition amount of these various fine particles is usually in the range of 0.01 to 10 parts by weight with respect to 100 parts by weight of the developer.
The non-magnetic one-component developer according to the present invention can be produced from each of the above components by a conventional method. Usually, a binder resin, a colorant and a release agent, and optionally a charge control agent, various fine particles, and other additives are uniformly dispersed and mixed in a mixer, and the resulting mixture is then mixed. After melt-kneading with a shaft extruder or the like, after cooling, coarsely crushed with a crusher, hammer mill, etc., finely crushed with a jet mill, high-speed rotor rotary mill, etc., wind classifier (for example, elbow jet of inertia classification method, A method of classifying with a centrifugal force classifying method such as microplex, DS separator, etc. is adopted.

In the present invention, the above-mentioned preferable wax dispersed particle size can be obtained by selecting specific production conditions. That is, in a kneading and pulverizing method including mixing, kneading, pulverizing, and classifying a toner constituent material such as the binder resin of the present invention and an ester wax, the kneading includes a plurality of temperature-adjustable cylinder blocks and two cylinder blocks. It is carried out by a twin-screw extruder having a screw rotatable in the same direction, and the screw is composed of at least a transport section, one or more kneading sections, and an extrusion section, and temperature setting of a cylinder block corresponding to the screw transport section. Is set to 20 ° C or more lower than the endothermic peak temperature of the release agent, and the cylinder block corresponding to the kneading part of the screw is 20 ° C or more higher than the endothermic peak temperature of the release agent and 10 ° C or more lower than the softening point of the binder resin. The cylinder block corresponding to the screw extruding part is set higher than the softening point of the binder resin by 20 ° C or more. If produced by Condition for preferred ranges wax dispersion diameter of the present invention is obtained.

In the screw of the twin-screw extruder, the transportation part is a process of compressing and conveying powder raw materials such as resin to give residual heat, but the set temperature of the cylinder block corresponding to that part is 20 ° C. or more from the wax endothermic peak temperature. By lowering the wax component, the wax component that has been uniformly powder-mixed by mixing is pushed into the next without being reaggregated and coarsened by heat. In kneading with a twin-screw extruder,
Generally, the residence time of the material such as resin in the apparatus is very short, and therefore, once the wax component becomes coarse, it is difficult to sufficiently disperse it in the subsequent steps. Next to the transport section, there are one or more kneading sections as screws, in which melting of resin and dispersion and mixing with additives such as wax are performed.
Then, by setting the set temperature of the cylinder block corresponding to the kneading portion to be higher than the wax endothermic peak temperature by 20 ° C. or more, the wax can be sharply melted to rapidly reduce the viscosity. Moreover, since the set temperature is lower than the softening point of the resin by 10 ° C. or more, the wax in the low viscosity state is dispersed in the resin having a sufficiently high viscosity and easily subjected to shearing force in an appropriate size. Further, the set temperature of the cylinder block corresponding to the screw extruding part is set to be 20 ° C. or more higher than the resin softening point, so that the overall viscosity can be greatly reduced and extruded without making a great change in the dispersion state in the kneading part. it can. As described above, the ester wax of the present invention is dispersed in the polyester resin of the present invention in a desired dispersed particle size. In addition,
In addition, in order to more appropriately obtain the wax dispersion diameter of the present invention, it is preferable to use a screw having two or more kneading parts in a twin-screw extruder and to provide a vent between them to draw a vacuum. . In addition, it is desirable to provide a water cooling mechanism inside the screw for cooling during kneading.

The powder characteristics of the toner have a great influence on the durability and the like of the developer of the present invention, and therefore must be properly controlled. That is, the particle size distribution of the toner preferably satisfies the following requirements. The measurement is by the Coulter counter method.

[0030]

[Table 2] [Arithmetic mean diameter] -The arithmetic mean diameter in the volume distribution is 5 to 15 µm, and more preferably 7 to 10 µm. -The arithmetic mean diameter in the number distribution is 4 to 15 m, more preferably 6 to 9 m. [Variation coefficient (CV value)]-The variation coefficient in the volume distribution is 30% or less, and more preferably 25% or less. -The coefficient of variation in the number distribution is 35% or less, more preferably 30% or less.

[0031]

[Table 3] [Amount of 5.04 μm or less] The amount of 5.04 μm or less in the volume distribution is 7% or less, more preferably 1 to 5%. The amount of 5.04 μm or less in the number distribution is 25% or less, more preferably 5 to 20%. [Amount of 10.1 μm or more] The amount of 10.1 μm or more in the volume distribution is 30% or less, more preferably 3 to 25%. The amount of 10.1 μm or more in the number distribution is 15% or less, more preferably 1 to 10%.

Further, the shape of the toner particles depends on the chargeability, the image quality,
Since it affects durability, it is important to set it in a desirable range. That is, the shape factor calculated by the following formula by an image analysis method (Luzex-F manufactured by Nireco Co., Ltd.) from an electron micrograph of particles is 120 to 180, and more preferably 140.
It should be between ~ 160. The numerical value fluctuates due to the distortion of the shape of the particles. The closer to a circle, the closer the numerical value is to 100, and the longer the elongated shape, the larger the numerical value.

[0033]

[Equation 1]

The non-magnetic one-component developer of the present invention is useful for an image forming method by the non-magnetic one-component developing system in electrophotography. An image forming method using the toner of the present invention will be described below. Hereinafter, the image forming method of the present invention will be described with reference to FIG. 1 as an example. The toner conveying member 1 used in the present invention usually has a cylindrical or cylindrical surface as a surface for carrying a developer. As a material, an elastic body is generally used in a so-called contact developing method in which the electrostatic latent image holding member 3 and the toner conveying member 1 are in contact with each other with the non-magnetic developer 6 interposed therebetween. The surface of the toner carrying member 1 may be provided with an appropriate surface roughness in order to improve the carrying property of the developer 6. In addition, it is necessary to consider a material that can obtain appropriate frictional charging with the toner particles. In the case of non-magnetic one-component contact type development, as a general form of the elastic toner conveying member 1, a conductive rubber roller (NBR rubber, silicone rubber or the like in which conductive particles are dispersed and contained) is used.
To use. A dielectric layer may be provided on the surface of the conductive rubber.

Toner layer thickness regulating member 2 used in the present invention
Examples include various types such as a rigid body having a rectangular rod shape, an elastic body having a protrusion shape, a leaf spring shape or the like that uses a surface or a tip, a roller, or the like, or a composite type thereof. Layer thickness control member 2
Is linearly pressed against the toner conveying member 1 by its own elastic force, the elastic force of the toner conveying member 1, an external force, or a combined force thereof. Regarding the electrical characteristics of the toner layer thickness regulating member 2, when a voltage is applied to an insulating material or a conductive material, or if it is a conductive material, it is electrically connected to nothing and floats. And so on. By relatively moving the toner conveying member 1 so as to slide in a direction perpendicular to the linear pressing, the developer particles 6 pass while spreading the pressing portion, and are uniformly applied onto the toner conveying member 1 to form the developer. Form the layers. The developer layer thickness and the toner charge amount are controlled by the form, pressure, composition and applied voltage of the pressing portion. Generally, the larger the pressure, the thinner the applied developer layer and the higher the amount of charge, but the morphology, pressure, composition, and applied voltage are complicated physical and chemical phenomena and cannot be generally discussed.

The electrostatic latent image holder 3 that holds the electrostatic latent image is
An electrostatic latent image pattern due to the electrostatic charge distribution is formed on the surface. In the image forming method of the present invention, OP is used as the latent image carrier.
C is used. As a general form, an organic photosensitive material containing a polycarbonate resin, an acrylic resin or the like is applied to the surface of a conductive base material formed of a metal cylinder such as aluminum or a thin film, and used. The photosensitive layer has a relative dielectric constant of about 1 to 5, and is generally used with a layer thickness of about 10 to 50 μm.

In the image forming process, a latent image is formed in accordance with the generally used principle of xerography, such as uniform charging by a corona charger, a contact type roller system, a brush system, etc., an exposure procedure by a lamp, a laser beam, etc. A latent image of electrostatic charge distribution is formed on the holder 3. The maximum potential on the latent image carrier 3 at this time is about 100 to 1200 V in absolute value, more preferably 300 to 90, based on the conductive base material.
It is controlled to be about 0V.

On the other hand, the developer 6 is applied to the toner conveying member 1 by the toner layer thickness regulating member 2 as described above. There is a case where no voltage is applied between the toner conveying member 1 and the toner layer thickness regulating member 2, a short circuit is made to have the same potential, or a voltage of about 500 V or less is applied.
Further, a toner replenishing auxiliary member 4 is provided upstream of the toner layer thickness regulating member 2 in the relative movement direction of the toner conveying member 1. As the replenishment auxiliary member 4, a member in which the developer 6 positively moves toward the toner conveying member 1 in addition to the force of the developer 6 adhering to the toner conveying member 1 due to its own weight and fluidity is used. For example, a method is used in which the developer 6 is included in a sponge-like or brush-like member and is slid on the toner conveying member 1. The friction at this time may be used to accelerate the triboelectrification of the developer 6. Using a conductive material for the supplementary auxiliary member 4,
A voltage may be applied between the developer 6 and the toner conveying member 1 so as to apply an electrostatic force toward the toner conveying member 1.
Further, since the roller-shaped endless toner conveying member 1 is generally used, the toner conveying member 1 to which the remaining developer after the development on the latent image holding member 3 is adhered is located at this supplementary auxiliary member 4. Since it comes back, it can also serve as a cleaning means. If you want to positively use the effect,
Conversely, a voltage may be applied so that a force is applied in the direction in which the developer 6 separates from the toner conveying member 1. Further, in the case of both cleaning and supply, an alternating electric field may be applied for the purpose of increasing the charge of the developer 6.

However, in order to reduce the cost of the apparatus, it is preferable to apply no voltage between the toner conveying member 1 and the supplementary auxiliary member 4. Further, when the developing device having the configuration as shown in FIG. 1 is used, the developer 6 may leak from the gap below the toner conveying member 1, so that the developer leak seal member 5 is generally attached. By the above process,
The toner conveying member 1 having the developer layer formed thereon and the electrostatic latent image carrier 3 having the latent image formed thereon face each other, and at least the toner particles in the developer 6 are transferred to visualize the latent image.

At this time, the toner particles corresponding to the latent image pattern are transferred by electrostatic force by being pressed through the developer layer. A general method is to keep the potential of the developing sleeve 1 at a potential between the latent image potential to which the toner is to be transferred and the latent image potential to be the white background. The toner transferred to the latent image pattern is further transferred to a transfer material such as paper or film in the case of an ordinary copying machine or a laser printer. In this transfer step, a method in which a transfer target material is brought into contact with a latent image carrier and a charge is applied from the back surface by corona discharge, or a method in which a conductive transfer roller is pressed to apply a voltage is generally used.

After the transfer step, the particles remaining on the latent image holding member are removed by rubbing with a cleaning blade 9 made of polyurethane or the like that contacts the photosensitive member. The toner image on the transfer material is fixed by a fixing member 10 such as a heat roller.

[0042]

EXAMPLES Specific examples of the present invention will be described below in more detail with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. [Polyester Resin Production Examples 1 to 6] The materials having the compositions shown in Table 1 below were placed in a reaction vessel equipped with a thermometer, a stirrer, and a nitrogen introducing tube and capable of depressurizing and heating, and further added with a polymerization catalyst. Then, the reaction was allowed to proceed while maintaining the internal temperature of the container under reduced pressure of about 250 ° C. while stirring under a nitrogen stream. The reaction state was traced while measuring the softening point, the reaction was stopped when predetermined physical properties were reached, and further cooled to room temperature to obtain each polyester resin.

[0043]

[Table 4]

In Table 1, acid components and alcohol components are represented by abbreviations, which represent the following raw materials.

[0045]

[Table 5] TPA: terephthalic acid IPA: isophthalic acid TMA: trimellitic acid diol A: polyoxyethylene (2.2) -2,2-
Bis (4-hydroxyphenyl) propanediol B: polyoxypropylene (2.2) -2,2
-Bis (4-hydroxyphenyl) propane EG: Physical properties of polyester resins having ethylene glycol or higher are shown in Table 2 below.

[0046]

[Table 6]

[Toner Composition Examples 1 to 16] Table 3 below shows a list of the toner compositions of Toner Composition Examples 1 to 16 and the kneading conditions.

[0048]

[Table 7]

[Nonmagnetic One-Component Developer Examples 1 to 16] Table-3
Each non-magnetic one-component developer is prepared as described below under the composition and kneading conditions of. According to each composition, they were mixed with a Henschel mixer and melt-kneaded with a twin-screw extruder. The screw of the extruder rotates in the same direction and has two kneading parts. In addition, vent suction in vacuum is performed between the first kneading portion and the second kneading portion. Further, about 10 ° C of water is passed through the screw for axial cooling. The kneading conditions are shown in Table-3.
As described in.

Next, the kneaded material is cooled and rolled by a cooling roller,
It is roughly crushed with a hammer mill to a particle size of about 1 mm. The coarsely crushed material is finely pulverized by a fluidized bed jet mill and classified by a rotor rotary type classifier. Further, with respect to 100 parts by weight of the obtained classified product, hydrophobic silica HDK-H1018 (Wack
1 part by weight (manufactured by er) is mixed with a Henschel mixer and externally added. Then, open the externally treated product to about 100
Coarse particles were removed by a vibrating sieve set with a sieve of μm to obtain a non-magnetic one-component developer. The physical properties of the resulting non-magnetic one-component developer are shown in Table 4 below (No. of the non-magnetic one-component developer example corresponds to Toner composition example No., respectively).

[0051]

[Table 8]

The arithmetic mean diameter, coefficient of variation, and 5.
Co is measured in an amount of 04 μm or less and 10.1 μm or more.
It was carried out with a uter Multisizer 2 (manufactured by Beckman Coulter, Inc.). The shape factor SF-1 is a scanning electron micrograph (SEM) of each of the toners, and a plurality of fields of view of 1000 times are photographed, and an image analysis of 100 particles at random is Luzex-F (manufactured by Nireco). Done by
It was calculated. The average dispersed particle diameter of the wax in the toner particles was measured by the method described in the text. The wax dispersion particle size is the same as that of the developer example No. 1 to 9 is 1 to 2 μm, and developer examples (comparative) 10, 11, 13, 14, and 16 are 2.5 μm.
m, and the developer example (comparative) 15 was less than 1 μm.

[Evaluation Method of Non-Magnetic One-Component Developer] Each developer was evaluated by a fixing property test and an actual copying durability test. The measuring method is as follows. (Fixing Property Test) The fixing device of a commercially available full-color printer was removed, and the temperature was set and modified so that it could be driven independently. The fixing device is a heat roller type, each of the upper and lower rollers is made of silicon rubber, a heater is built in the upper roller (toner contact surface), and a PTFE tube is covered on the outermost surface. The rotation speed of the roller is about 80 mm /
Let be sec. The surface temperature of the upper roller of the fixing machine is 1
The temperature is set in the range of 30 to 230 ° C in steps of 10 ° C. Separately, a basis weight of about 80 g / m ² plain paper (A4 size) the toner adhesion amount of about over 0.6 mg / cm ²
The band-shaped solid is printed with to obtain an unfixed printed image. This unfixed image was passed through the above-mentioned fixing machine whose temperature was set to obtain a fixed image at each temperature. Then, the presence or absence of the offset phenomenon is visually checked, and the temperature range in which the offset phenomenon does not occur is set as the offset temperature range. Also, the fixing temperature is 170
The fixing strength was evaluated by the solid folding method (ratio% of image density before and after folding) using the image at ° C. The evaluation may be performed by using a toner that does not cause an offset in a wider temperature range and has a high bending strength (the image of the fold portion after the bending is difficult to peel off) as the fixing property, but is performed as follows.

[0054]

[Table 9] Offset temperature range: It is preferable that the difference between the upper limit temperature and the lower limit temperature is 70 ° C or more, and there is a problem in practical use at 50 ° C or less. Bending fixing strength: 90% or more is preferable, and if less than that, there is a practical problem.

(Real-image shooting durability test) The real-image evaluation was performed using a non-magnetic one-component developer. The live-action image evaluation device was used by modifying a commercially available tandem printer. The photoreceptor (image carrier) of this printer is a drum-shaped laminated organic photoconductor (OPC) having a diameter of 24 mm and containing a polycarbonate resin in the surface layer, and the developing device is made of a rubber containing a conductive agent. A urethane rubber blade (layer thickness regulating member) and a sponge-like supply roller (supplementary supplement member) are pressed against the developing sleeve (conveying member). These photoconductors, developing devices, etc. are assigned for each color, and a total of four colors are arranged in series. The paper is conveyed by a conveyor belt. The fixing is performed by a heat roll having no silicone oil supply mechanism, and the surface layer of the upper roller (toner contact surface) is made of PTFE,
It is set to have a surface temperature of about 180 ° C. The lower roller is made of silicone rubber.

About 360 g of each color developer in each of the four color developing devices
It is supplied and a printing test is performed on about 6000 sheets with a 4-color pattern having a solid density of 10% (A4 size) for each color. During that time, patterns for image evaluation were printed on the initial 2000, 4000, and 6000 sheets. The image evaluation is performed as follows.

[0057]

[Table 10] Image density: measured with a color difference meter SPM-50 (manufactured by Gretag). It should be 1.40 or higher throughout all tests. Fog: Color difference meter Z-300 that measures the whiteness difference before and after passing the paper.
It was measured with A (manufactured by Nippon Denshoku Co., Ltd.). 1.0 throughout all tests
It should be: White streak and solid uniformity: visually evaluated in the following four grades ◎: Very good ○: No problem in practical use △: Some problem in practical use ×: Significant problem in practical use and toner consumption by measuring the weight of each developing device (G / 10
(00 sheets) is calculated. As a guide, average 50g
It is preferable that the number is less than 1000 sheets.

[Evaluation Results of Non-Magnetic One-Component Developer] Non-magnetic one-component developers Examples 1 to 16 were tested for fixability and actual copying durability. The results are shown in Table 5 below.

[0059]

[Table 11]

As a result, in Developer Examples 1 to 9, the offset temperature range was over 70 ° C., the bending fixing strength was over 90%, the image density was 1.40 or more, and the fog was 1.0 or less in the actual copying test. The generation of white streaks and the uniformity of solids were at a level of practically no problem, and the average toner consumption was less than 50 g / 1000 sheets, which were all excellent results.

On the other hand, Comparative Developer Examples 10 to 16
Had some drawbacks as follows. Developer Example 10: An example in which polyoxyethylenated bisphenol A is not included as a constituent material of the polyester resin, but the wax dispersion diameter is large, and the image density in the latter half of the actual image is reduced, white streaks are generated, and solid uniformity is reduced. Is getting worse,
There are practical problems.

Developer Example 11: This is an example in which polyoxyethylenated bisphenol A was not included as a constituent material of the polyester resin, but the wax dispersion diameter was large and the image density decreased in the latter half of the actual shooting, the occurrence of white streaks and the solid uniformity. Is worse, which is a practical problem. Developer Example 12: This is an example in which polyethylene wax was used in place of the ester wax, but the fixing offset temperature range was only 40 ° C., and the fixability was poor.

Developer Example 13: The case where the set temperature of the cylinder block corresponding to the screw transporting section at the time of kneading is not lower than the endothermic peak temperature of wax by 20 ° C. or more. Occurrence of streaks and deterioration of solid uniformity are observed, which is a problem in practical use.

Developer Example 14: The case where the set temperature of the cylinder block corresponding to the screw kneading portion at the time of kneading was not higher than the endothermic peak temperature of wax by 20 ° C. or more. Occurrence of white stripes and deterioration of solid uniformity were observed, and the average toner consumption was also rather high, which was a practical problem.

Developer Example 15: In the case where the set temperature of the cylinder block corresponding to the screw kneading portion at the time of kneading is not lower than the softening point of the resin by 10 ° C. or more, the wax dispersion diameter is small, and the solid image in the latter half of the actual shooting is small. The uniformity is deteriorated, and the average toner consumption is also deteriorated, which is a practical problem.

Developer Example 16: The set temperature of the cylinder block corresponding to the extruded portion at the time of kneading is 20 than the softening point of the resin.
Although it is not higher than 0 ° C., the wax dispersion diameter is large, white streaks are generated in the latter half of actual copying, and solid uniformity is deteriorated, which is a problem in practical use.

[0067]

EFFECTS OF THE INVENTION The present invention has both excellent fixing properties (offset resistance, etc.) and excellent blade fusion resistance, and further has improved durability during repeated use and continuous use. A method for producing a non-magnetic one-component developer having

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing a useful example of an image forming method of the present invention using a non-magnetic one-component developer according to the present invention.

[Explanation of symbols]

1 Toner transport member 2 Toner layer thickness control member 3 Electrostatic latent image holder 4 Toner supply auxiliary member 5 Developer leak seal member 6 Non-magnetic one-component developer 7 Latent image carrier charging member 8 Transfer member 9 Cleaning blade 10 Fixing member

Claims (3)

[Claims] 1. A method for producing a non-magnetic one-component developer, which comprises mixing at least a binder resin, a colorant and a release agent, kneading, pulverizing and classifying, wherein the binder resin is an aromatic dicarboxylic acid. A polyester having a softening point of 100 to 140 ° C., which comprises a polyvalent carboxylic acid component containing an acid and an aromatic tricarboxylic acid and a polyhydric alcohol component containing an aromatic diol, and at least a part of the aromatic diol is a polyoxyethylenated bisphenol. An ester wax containing a resin and having a release agent having an endothermic peak measured by a differential scanning calorimeter (DSC) at 50 to 90 ° C., a plurality of cylinder blocks in which kneading is possible, and two cylinder blocks in the same direction. It is carried out by a twin-screw extruder having a rotatable screw, and the screw has at least a transport section and one or more kneading sections. And the extruding section, the temperature of the cylinder block corresponding to the screw transport section is set lower than the endothermic peak temperature of the release agent by 20 ° C. or more, and the cylinder block corresponding to the kneading section of the screw is set to the release agent. The endothermic peak temperature is set to 20 ° C. or higher and the softening point of the binder resin is set to 10 ° C. or lower, and the cylinder block corresponding to the screw extruding portion is set to 20 ° C. or higher to the softening point of the binder resin. Manufacturing method of non-magnetic one-component developer. 2. The method for producing a non-magnetic one-component developer according to claim 1, wherein the release agent is dispersed in the polyester resin with a number average diameter of 1 to 2.5 μm. 3. The nonmagnetic one-component developer according to claim 1, wherein the release agent is an ester wax composed of a monovalent carboxylic acid having 18 or more carbon atoms and a monohydric alcohol having 18 or more carbon atoms. Manufacturing method.