JP4434177B2 - Non-magnetic one-component electrostatic latent image developing method, image forming method, image forming apparatus and toner used therefor - Google Patents

Description

  The present invention relates to a non-magnetic one-component electrostatic latent image developing method, an image forming method, an image forming apparatus, and a toner used for the same.

  As non-magnetic one-component development systems, for example, systems described in JP-A-62-212946, JP-A-63-271374, JP-A-2774534, and the like are known. This system includes a toner conveying member, a toner layer regulating member, and a toner replenishing auxiliary member, and is thinned using a developing device in which the toner replenishing auxiliary member and the toner conveying member are in contact with each other. In this system, layered nonmagnetic toner is supplied to the surface of the electrostatic latent image forming body to develop the latent image. In this method, the nonmagnetic toner is charged by frictional charging between the nonmagnetic toner and the toner conveying member or the toner layer regulating member.

  However, when this method is used, fogging or the like is observed when used for a long time as a major problem, and this solution is required. The main reason for this phenomenon is that the toner is likely to be fused to the member for conveying the toner and the member for regulating the toner layer, and as a result, the triboelectric charging property is lowered, so that the nonmagnetic property is reduced. This is considered to be due to a decrease in the charge amount of the toner.

  Further, in the conventional pulverized toner, toner fine powder is generated during pulverization, and it is difficult to remove it by classification, and it remains in the final toner. When toner containing such fine powder is used, the fine powder itself has strong adhesion, so it does not move while adhering to the surface of the toner conveying member, and is repeatedly stressed by the toner layer regulating member, etc. It fuse | melts and will reduce the charge provision capability of a conveyance member. As a result, fogging or the like is likely to occur due to a decrease in the charge amount of the nonmagnetic toner and an increase in the charge amount distribution (such as an increase in the weakly chargeable toner amount).

  Further, as a solution to the above-mentioned problem of fine powder toner, in JP-A-60-31147, JP-A-60-107656 and JP-A-60-117255, a suspension polymerization toner having a spherical shape and a small particle size distribution is disclosed. Has been proposed. However, since the suspension-polymerized toner is spherical, it tends to be excessively conveyed from the toner layer regulating member, and the charging property may not be sufficiently provided. Furthermore, since the spherical shape has strong adhesion to the photoconductor, there is a problem that it is difficult to clean.

  For this reason, in order to solve the above problems, there has been a proposal to change the shape of the toner to one having irregularities on the toner surface rather than a true spherical shape. For example, Japanese Patent Application Laid-Open No. 7-36207 proposes an image forming method in which the level of toner deforming is defined by a shape factor to solve these problems.

  However, the toner deforming means disclosed in this document is a conventional method in which the resin particles are attached to the surface of the suspension polymerization toner, or the suspension polymerization toner is immersed in a solvent to swell, and then the pressure is reduced. It is a method of drying and deforming. When the suspension polymerization toner surface is deformed by attaching resin particles, the resin particles adhering to the surface are separated from the toner surface due to frictional stress between the toner conveying member and the toner layer regulating member, or charged charges are concentrated on the resin particles on the surface. However, the charge amount distribution tends to be broad, and the resolution of characters is deteriorated. Further, a toner in which a suspension-polymerized toner is swollen by immersing it in a solvent so as to have a deformed surface has problems that the toner characteristics are likely to be unstable due to differences in production lots and the image is not stable. As a result, although it is a non-magnetic one-component development system that is a simple and useful technique, it has not been possible to achieve stable image formation over a long period of time.

  On the other hand, in recent years, the electrophotographic system is used in various fields. For example, it is used not only in monochrome copying machines but also in the fields of printers as computer output terminals, color copying machines, color printers, and the like. As the use of these advances, the demand for image quality is increasing, but it is necessary to achieve both compactness and simplified mechanism. The one-component development method using a developer composed only of toner as a development method has various applications due to its simplicity. In particular, the non-magnetic one-component development method using non-magnetic toner does not contain magnetic powder in the toner, so it has good environmental characteristics and can be colorized. is there.

  However, as described above, in this development method, a toner layer is formed as a thin layer on the surface of the developer conveying member in a state where the developer conveying member made of an elastic body and the photosensitive member are in contact with each other, and contact development is performed. It is common to do it. Therefore, it is necessary to form the toner layer uniformly in a thin layer, and also in terms of chargeability, unlike the two-component developer, since there is no carrier as an electricity applying member, friction charging with the developer conveying member is required. It is necessary to quickly start up uniform charging.

For this reason, as a non-magnetic one-component development system, improvements from various toner surfaces and development systems have been proposed (for example, Patent Document 1). However, in the examination so far, the improvement has been insufficient, and when the above-mentioned problems are improved to some extent, problems that have not been regarded as problems so far have become clear. For example, there is a phenomenon called so-called development ghost, in which toner is not sufficiently replenished to the developing sleeve portion where the toner layer once subjected to development is adsorbed. For this reason, a phenomenon of insufficient development density occurs due to a shortage of toner, or toner with different chargeability accumulates on the developer conveying member due to long-term use, causing problems such as fogging. Furthermore, it is easily affected by environmental fluctuations, and problems such as fogging due to charging leakage in a high temperature and high humidity environment may occur.
Japanese Patent Laid-Open No. 9-50150

An object of the present invention is a non-magnetic one-component electrostatic that can form an image without high-quality high density and low fog density, which is stable over a long period of time, and without halftone image unevenness, without being affected by environmental fluctuations. It is an object to provide a latent image developing method, an image forming method, an image forming apparatus, and a toner used therefor.

  The inventors of the present invention have intensively studied and analyzed the charging deterioration phenomenon in the non-magnetic one-component development, and as a result, the present invention has been completed. The inventors of the present invention have found out that the shape and distribution of a specific toner, as well as the presence or absence of a specific angle, etc. are greatly related to the decrease in charge imparting ability in magnetic one-component development. It was. A solution to the problem has been found and the present invention has been completed.

  That is, the object of the present invention is achieved by adopting one of the following configurations.

(1)
The developing device is provided with a toner conveying member, a toner layer regulating member, and a toner replenishing auxiliary member, and is thinned using a developing device in which the toner replenishing auxiliary member and the toner conveying member are in contact with each other. In the non-magnetic one-component electrostatic latent image developing method in which the non-magnetic toner is supplied to the surface of the electrostatic latent image forming body to develop the latent image, the toner polymerizes at least a polymerizable monomer in an aqueous medium. and made by associating the resulting resin particles in an aqueous medium, it is no angular toner particles 50% by number or more in the following measurement method, and wherein the number variation coefficient in the number particle size distribution is not more than 27% A non-magnetic one-component electrostatic latent image developing method.
(Measurement method)
When the inner diameter of the toner particle is a circle having a major axis L and L / 10 is a radius R, and the inner side of the toner particle is in contact with the inner circumference of the toner particle at one point, the circle is substantially outside the toner. The case where it does not start is called toner particles having no corners. The case where it does not protrude substantially refers to one or less protrusions where the protruding circle exists. The major axis of the toner particles refers to the width of the particle that maximizes the interval between the parallel lines when the projected image of the toner particles on the plane is sandwiched between two parallel lines.
To measure the toner having no corners, first, a photograph in which the toner particles are enlarged is taken with a scanning electron microscope, and further enlarged to obtain a 15,000 times photographic image. The photographic image is then measured for the presence or absence of the corners. This measurement is performed on 100 toner particles.

(2)
An image forming method comprising the steps of latent image formation, development, transfer, and fixing using the nonmagnetic one-component electrostatic latent image developing method described in (1).

(3)
The image forming method according to (2), wherein the toner used contains 65% by number or more of toner particles having a shape factor in the range of 1.0 to 1.6.

(4)
The image forming method as described in (2 ), wherein the toner used contains 65% by number or more of toner particles having a shape factor in the range of 1.2 to 1.6.

(5)
The image forming method according to (2), (3) or (4), wherein the toner used has a number average particle diameter of 3 to 8 μm.

(6)
When the particle size of the toner particles used is D (μm), a natural logarithm lnD is taken on the horizontal axis, and the horizontal axis is a histogram showing the number-based particle size distribution divided into a plurality of classes at intervals of 0.23. The sum (M) of the relative frequency (m1) of toner particles contained in the most frequent class and the relative frequency (m2) of toner particles contained in the next most frequent class after the most frequent class is 70% or more. The image forming method as described in (2) or (3) above.

( 7 )
An image forming apparatus comprising the steps of forming a latent image, developing, transferring, and fixing using the non-magnetic one-component electrostatic latent image developing method described in (1).

( 8 )
The developing device is provided with a toner conveying member, a toner layer regulating member, and a toner replenishing auxiliary member, and is thinned using a developing device in which the toner replenishing auxiliary member and the toner conveying member are in contact with each other. In the toner used in the nonmagnetic one-component electrostatic latent image developing method for developing the latent image by supplying the nonmagnetic toner to the surface of the electrostatic latent image forming body, the toner contains at least a polymerizable monomer in an aqueous medium. The number of toner particles having no corners in the following measurement method is 50% by number or more, and the number variation coefficient in the number particle size distribution is 27% or less. Toner characterized by the above.
(Measurement method)
When the inner diameter of the toner particle is a circle having a major axis L and L / 10 is a radius R, and the inner side of the toner particle is in contact with the inner circumference of the toner particle at one point, the circle is substantially outside the toner. The case where it does not start is called toner particles having no corners. The case where it does not protrude substantially refers to one or less protrusions where the protruding circle exists. The major axis of the toner particles refers to the width of the particle that maximizes the interval between the parallel lines when the projected image of the toner particles on the plane is sandwiched between two parallel lines.
To measure the toner having no corners, first, a photograph in which the toner particles are enlarged is taken with a scanning electron microscope, and further enlarged to obtain a 15,000 times photographic image. The photographic image is then measured for the presence or absence of the corners. This measurement is performed on 100 toner particles.

  The reason why the object of the present invention is achieved by the above-described configurations is not fully understood, but is considered as follows.

  In the non-magnetic one-component development, since the carrier is not used, the toner itself is frictionally charged with the developer conveying member and the toner is charged. For this reason, if there is a distribution in the surface properties of the toner itself, there is a problem that a difference occurs in the tribocharging property and the charge amount distribution is widened. Development itself is often contact development, and the latitude is quite large, but a phenomenon such as development ghost is likely to occur. That is, toner having a high charge amount has strong adhesion to the surface of the developer conveying member, so that it is difficult for replacement to occur, and as a result, a problem of developing ghosts due to less replacement of the developer tends to occur. Furthermore, when the environment fluctuates, the difference in charge amount increases, and charge leakage in a high-temperature and high-humidity environment tends to occur and fogging is likely to occur.

  As a result of intensive studies, the present inventors have suppressed the generation of fine particles generated due to stress on a portion where the toner contacts, such as a developer conveying member, due to the smoothness of the surface of toner particles having no corners. Because there is no accumulation of excessive chargeability due to triboelectric charging due to its smooth surface properties, problems such as development ghosts are less likely to occur, and the same effect is exhibited even if the shape variation is somewhat large I found out. That is, it has been found that the problem of the present invention can be solved by using a toner having 50% by number or more of toner particles having no corners and a number variation coefficient of 27% or less in the number particle size distribution.

  As a result of studying toner particles that easily contaminate the developer conveying member and the charge imparting member, the present inventors have found that toner particles having irregular shapes and corner portions are not formed when the image forming process is repeated. The toner particles contained tend to be easily contaminated. Although the reason for this is not clear, when the toner particles are irregularly shaped, the toner composition is susceptible to mechanical stress due to stirring or the like inside the developing device, and a portion to which excessive stress is applied is generated. Was transferred to the contaminated material and adhered, and the chargeability of the toner was estimated to change.

  Further, the difference in how stress is applied varies depending on the particle size of the toner particles, and the smaller particle size has a higher adhesive force, so that it is likely to be contaminated when subjected to stress. When the toner particle size is large, such contamination is less likely to occur, but there is a problem that the image quality such as resolution is lowered.

  Furthermore, the initial toner charge amount distribution is also important for such contamination. When the charge amount distribution is wide, so-called selective development occurs in the image forming process, and toner particles that are difficult to develop accumulate in the developing device and developability deteriorates. Due to the stress, there is a problem that contamination occurs or the surface property of the toner changes to change the chargeability, resulting in a weakly charged toner or a toner having a reverse polarity, resulting in a deterioration in image quality.

  As a result of examining the toner charge amount distribution, in order to make the toner charge amount distribution extremely sharp, it is necessary to control the variation in the particle size of the toner particles to be small and the shape variation to be small. It has been found. By making the toner charge amount distribution extremely sharp, even when the toner charge amount is set low, it is possible to obtain stable chargeability over a long period of time.

  In addition, as a result of investigations by paying attention to the minute shape of each toner particle, the present inventors have changed the shape of the corner portion of the toner particle to become round inside the developing device, and the portion is contaminated. It was found that it was generated. Although the reason for this is not clear, it is presumed that stress is easily applied to the corner portion, and the toner composition moves to and adheres to the contaminated substance due to wear and fracture of this portion, thereby changing the chargeability of the toner. Further, when charge is applied to the toner particles by frictional charging, it is presumed that the charge tends to concentrate particularly at the corners and the toner particles are likely to be non-uniformly charged.

  In other words, by controlling the number of toner particles having no corners to 50% by number or more and controlling the number variation coefficient in the number particle size distribution to 27% or less, a high-quality image can be formed over a long period of time with excellent developability and fine line reproducibility. As a result, the present invention has been completed.

  The shape factor of the toner of the present invention is represented by the following formula and indicates the degree of roundness of the toner particles.

Shape factor = ((maximum diameter / 2) ² × π) / projection area Here, the maximum diameter is the distance between the parallel lines when the projected image of toner particles on a plane is sandwiched between two parallel lines. The maximum particle width. The projected area refers to the area of the projected image of the toner particles on the plane.

  In the present invention, this shape factor is obtained by taking a photograph in which the toner particles are magnified 2000 times with a scanning electron microscope, and then using “SCANNING IMAGE ANALYZER” (manufactured by JEOL Ltd.) based on this photograph. It was measured by performing analysis. At this time, the shape factor of the present invention was measured by the above formula using 100 toner particles.

  In the above configuration, the number of toner particles having a shape factor in the range of 1.0 to 1.6 is preferably 65% by number or more, and more preferably 70% by number or more. More preferably, the number of toner particles having a shape factor in the range of 1.2 to 1.6 is 65% by number or more, and more preferably 70% by number or more.

  When the number of toner particles having a shape factor in the range of 1.0 to 1.6 is 65% by number or more, the triboelectric chargeability on the developer conveying member and the like becomes more uniform, and excessively charged toner is accumulated. In addition, since it becomes easier to replace the toner from the surface of the developer conveying member, problems such as development ghost are less likely to occur. Further, the toner particles are less likely to be crushed, the contamination of the charging member is reduced, and the chargeability of the toner is stabilized.

  The method for controlling the shape factor is not particularly limited. For example, a method in which toner particles are sprayed into a hot air stream, a method in which toner particles are repeatedly applied with mechanical energy due to impact force in a gas phase, or a method in which a toner is not dissolved in a solvent and a swirl flow is applied. To prepare a toner having a shape factor of 1.0 to 1.6, or 1.2 to 1.6, and adding the toner into a normal toner so as to be within the range of the present invention. There is. In addition, there is a method of preparing a toner having a shape factor adjusted to 1.0 to 1.6 or 1.2 to 1.6 by controlling the overall shape at the stage of adjusting a so-called polymerization method toner.

  Among the above methods, the polymerization toner is preferable because it is simple as a production method and has excellent surface uniformity as compared with the pulverized toner.

According to the present invention, a non-magnetic one-component electrostatic latent image capable of forming an image free from the influence of environmental fluctuations and capable of forming a high-quality, high-density , low-fogging density that is stable over a long period of time and has no halftone image unevenness. A developing method, an image forming method, an image forming apparatus, and a toner used therefor can be provided.

  The toner of the present invention is produced by subjecting a monomer to emulsion polymerization in a suspension polymerization method or a liquid obtained by adding an emulsified liquid of necessary additives to produce fine polymer particles. It can manufacture by the method of adding and associating. A method of preparing by mixing with a dispersion liquid such as a release agent and a colorant necessary for the composition of the toner at the time of association, and a toner component such as a release agent and a colorant dispersed in the monomer And a method of emulsion polymerization. Here, the association means that a plurality of resin particles and colorant particles are fused.

  In addition, the aqueous medium as used in the field of this invention shows what contained 50 mass% or more of water at least.

  That is, various constituent materials such as a colorant and, if necessary, a release agent, a charge control agent, and a polymerization initiator are added to the polymerizable monomer, and a homogenizer, a sand mill, a sand grinder, an ultrasonic disperser, etc. Various constituent materials are dissolved or dispersed in the polymerizable monomer. The polymerizable monomer in which these various constituent materials are dissolved or dispersed is dispersed in oil droplets having a desired size as a toner in an aqueous medium containing a dispersion stabilizer using a homomixer or a homogenizer. Thereafter, the stirring mechanism is transferred to a reaction apparatus which is a stirring blade described later, and the polymerization reaction is advanced by heating. After completion of the reaction, the dispersion stabilizer is removed, filtered, washed, and dried to prepare the toner of the present invention.

  As a method for producing the toner of the present invention, a method of preparing the resin particles by associating or fusing them in an aqueous medium can also be mentioned. This method is not particularly limited, and examples thereof include methods described in JP-A Nos. 5-265252, 6-329947, and 9-15904.

  A method of associating a plurality of dispersed particles of constituent materials such as resin particles and a colorant, or a plurality of fine particles composed of a resin and a colorant, in particular, after dispersing them in water using an emulsifier, At the same time as adding a flocculant and salting out, the particle size was gradually grown while forming the fused particles by heating and fusing above the glass transition temperature of the polymer itself, and the desired particle size was achieved. By the way, the particle size growth is stopped by adding a large amount of water, and the shape is controlled by smoothing the particle surface while heating and stirring, and the particles are heated and dried in a fluid state while containing water. Toner can be formed. Here, an organic solvent that is infinitely soluble in water may be added simultaneously with the flocculant.

  As the polymerizable monomer constituting the resin, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decyl Styrene, styrene such as pn-dodecylstyrene or styrene derivatives, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, Methacrylic acid ester derivatives such as lauryl tacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, acrylic Isobutyl acid, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, acrylic acid ester derivatives such as phenyl acrylate, olefins such as ethylene, propylene, isobutylene, vinyl chloride, vinylidene chloride, odor Halogenated vinyls such as vinyl fluoride, vinyl fluoride, vinylidene fluoride, vinyl esters such as vinyl propionate, vinyl acetate, vinyl benzoate, vinyl methyl ether, vinyl ethyl ether Vinyl ethers such as vinyl, vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone, vinyl hexyl ketone, N-vinyl compounds such as N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone, vinyl naphthalene, vinyl pyridine, etc. There are acrylic acid or methacrylic acid derivatives such as vinyl compounds, acrylonitrile, methacrylonitrile, acrylamide and the like. These vinyl monomers can be used alone or in combination.

  Further, it is more preferable to use a combination of monomers having an ionic dissociation group as the polymerizable monomer constituting the resin. For example, it has a substituent such as a carboxyl group, a sulfonic acid group, a phosphoric acid group as a constituent group of the monomer, specifically, acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumar Acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrene sulfonic acid, allyl sulfosuccinic acid, 2-acrylamido-2-methylpropane sulfonic acid, acid phosphooxyethyl methacrylate, 3-chloro-2-acid phosphooxy And propyl methacrylate.

  Furthermore, multifunctional such as divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, etc. It is also possible to use a crosslinkable resin by using a functional vinyl.

  These polymerizable monomers can be polymerized using a radical polymerization initiator. In this case, an oil-soluble polymerization initiator can be used in the suspension polymerization method. Examples of the oil-soluble polymerization initiator include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carboxyl). Nitriles), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azo- or diazo-based polymerization initiators such as azobisisobutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate , Cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis- (4,4- t-butylperoxycyclohexyl) propane, tris The (t-butylperoxy) triazine peroxide polymerization initiator or a peroxide, such as and the like polymeric initiator having a side chain.

  In the case of using an emulsion polymerization method, a water-soluble radical polymerization initiator can be used. Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and its salts, hydrogen peroxide and the like.

  Dispersion stabilizers include tricalcium phosphate, magnesium phosphate, zinc phosphate, aluminum phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate , Bentonite, silica, alumina and the like. Furthermore, those generally used as surfactants such as polyvinyl alcohol, gelatin, methylcellulose, sodium dodecylbenzenesulfonate, ethylene oxide adduct, and higher alcohol sodium sulfate can be used as the dispersion stabilizer.

  As the resin excellent in the present invention, those having a glass transition point of 20 to 90 ° C. are preferred, and those having a softening point of 80 to 220 ° C. are preferred. The glass transition point is measured by a differential calorimetric analysis method, and the softening point can be measured by a Koka flow tester. Further, these resins preferably have a molecular weight measured by gel permeation chromatography of 1,000 to 100,000 in terms of number average molecular weight (Mn) and 2000 to 1,000,000 in terms of mass average molecular weight (Mw). Further, the molecular weight distribution is preferably such that Mw / Mn is 1.5 to 100, particularly 1.8 to 70.

  The flocculant used is not particularly limited, but those selected from metal salts are preferably used. Specifically, as a monovalent metal, for example, an alkali metal salt such as sodium, potassium or lithium, as a divalent metal, for example, an alkaline earth metal salt such as calcium or magnesium, or a divalent metal such as manganese or copper. And salts of trivalent metals such as iron and aluminum, and specific salts include sodium chloride, potassium chloride, lithium chloride, calcium chloride, zinc chloride, copper sulfate, magnesium sulfate, manganese sulfate, etc. Can be mentioned. These may be used in combination.

  These flocculants are preferably added in an amount equal to or higher than the critical aggregation concentration. The critical flocculation concentration is an index relating to the stability of the aqueous dispersion, and indicates a concentration at which flocculation occurs when a flocculant is added. This critical aggregation concentration varies greatly depending on the emulsified components and the dispersant itself. For example, it is described in Seizo Okamura et al., “Polymer Chemistry 17, 601 (1960) edited by the Japanese Society of Polymer Science”, and the like, and a detailed critical aggregation concentration can be obtained. As another method, a desired salt is added to the target particle dispersion at different concentrations, the ζ (zeta) potential of the dispersion is measured, and the salt concentration at which this value changes is defined as the critical aggregation concentration. You can ask for it.

  The addition amount of the flocculant of the present invention may be not less than the critical aggregation concentration, but is preferably 1.2 times or more, more preferably 1.5 times or more the critical aggregation concentration.

  The solvent that dissolves infinitely means a solvent that dissolves infinitely in water, and in the present invention, a solvent that does not dissolve the formed resin is selected. Specific examples include alcohols such as methanol, ethanol, propanol, isopropanol, t-butanol, methoxyethanol, and butoxyethanol, nitriles such as acetonitrile, and ethers such as dioxane. In particular, ethanol, propanol, and isopropanol are preferable.

  The addition amount of the infinitely soluble solvent is preferably 1 to 100% by volume with respect to the polymer-containing dispersion to which the flocculant is added.

  In order to make the shape uniform, it is preferable to fluidly dry a slurry containing 10% by mass or more of water based on the particles after preparing and filtering colored particles. Those having a polar group are preferred. The reason for this is considered to be that it is particularly easy to make the shape uniform, in order to exhibit the effect that the water present is somewhat swollen with respect to the polymer in which the polar group is present.

  The toner of the present invention contains at least a resin and a colorant, but may contain a release agent, a charge control agent, or the like, which is a fixability improving agent, if necessary. Further, an external additive composed of inorganic fine particles or organic fine particles may be added to the toner particles containing the resin and the colorant as main components.

  As the colorant used in the toner of the present invention, carbon black, a magnetic material, a dye, a pigment, and the like can be arbitrarily used. Examples of the carbon black include channel black, furnace black, acetylene black, thermal black, and lamp black. used. Magnetic materials include ferromagnetic metals such as iron, nickel and cobalt, alloys containing these metals, compounds of ferromagnetic metals such as ferrite and magnetite, alloys that do not contain ferromagnetic metals but exhibit ferromagnetism by heat treatment, For example, a kind of alloy called Heusler alloy such as manganese-copper-aluminum, manganese-copper-tin, chromium dioxide, or the like can be used.

  As the dye, C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95 etc. can be used, and a mixture thereof can also be used. Examples of the pigment include C.I. I. Pigment Red 5, 48: 1, 53: 1, 57: 1, 122, 139, 144, 149, 166, 177, 178, 222, C.I. I. Pigment Orange 31 and 43, C.I. I. Pigment yellow 14, 17, 93, 94, 138, C.I. I. Pigment green 7, C.I. I. Pigment Blue 15: 3, 60, etc. can be used, and a mixture thereof can also be used. The number average primary particle diameter varies depending on the type, but is preferably about 10 to 200 nm.

  As a method for adding the colorant, the polymer particles prepared by the emulsion polymerization method are added at the stage of agglomerating by adding an aggregating agent, and the polymer is colored, or at the stage of polymerizing the monomer. The method of adding, polymerizing, and making it a colored particle etc. can be used. In addition, when adding a coloring agent in the step which prepares a polymer, it is preferable to use it, treating the surface with a coupling agent etc. so that radical polymerization property may not be inhibited.

  Further, a low molecular weight polypropylene (number average molecular weight = 1500 to 9000), a low molecular weight polyethylene, or the like as a fixing property improving agent may be added.

  Similarly, various known charge control agents and those that can be dispersed in water can be used. Specific examples include nigrosine dyes, naphthenic acid or higher fatty acid metal salts, alkoxylated amines, quaternary ammonium salt compounds, azo metal complexes, salicylic acid metal salts or metal complexes thereof. These charge control agent and fixability improving agent particles preferably have a number average primary particle size of about 10 to 500 nm in a dispersed state.

  In a suspension polymerization method toner in which a toner component obtained by dispersing or dissolving a toner component such as a colorant in a so-called polymerizable monomer is suspended in an aqueous medium and then polymerized. The shape of the toner particles can be controlled by controlling the flow of the medium. That is, when a large amount of toner particles having a shape factor of 1.2 or more are formed, the flow of the medium in the reaction vessel is turbulent and the polymerization proceeds to exist in an aqueous medium in a suspended state. When the oil droplets gradually become polymerized, the oil droplets become soft particles. By colliding the particles, particle coalescence is promoted, and particles with an irregular shape are obtained. . When spherical toner particles having a shape factor smaller than 1.2 are formed, spherical particles can be obtained by using a laminar flow of the medium in the reaction vessel to avoid particle collision. By this method, the toner shape distribution can be controlled within the scope of the present invention.

  In the suspension polymerization method, a turbulent flow can be formed by using a specific stirring blade, and the shape can be easily controlled. Although the reason for this is not clear, when the configuration of the stirring blade attached to the rotary shaft as shown in FIG. 1 is used in a single stage, the flow of the medium formed in the stirring tank is Only the flow moves along the wall surface from the lower part to the upper part of the stirring tank. Therefore, conventionally, a baffle plate such as a wall surface of a stirring tank is generally arranged to form a turbulent flow and increase the efficiency of stirring. However, in such an apparatus configuration, although the turbulent flow is partially formed, the fluid flow acts rather in the direction of stagnation due to the presence of the turbulent flow, resulting in less shear stress on the particles. Can not control.

  A stirring tank provided with a stirring blade that can be preferably used will be described with reference to the drawings. FIG. 2 is an example of a stirring tank provided with a stirring blade. A rotating shaft 3 is suspended from the central portion of a vertical cylindrical stirring tank 2 fitted with a heat exchange jacket 1 on the outer periphery of the stirring tank, and is brought close to the bottom surface of the stirring tank 2. There are a lower stirring blade 4 disposed and a stirring blade 5 disposed further above. The upper stirring blade 5 is disposed with a crossing angle α preceding the stirring blade 4 positioned in the lower stage in the rotational direction. In the present invention, the crossing angle α is preferably less than 90 degrees (°). The lower limit of the crossing angle is not particularly limited, but may be particularly preferably about 5 degrees or more, preferably 10 degrees or more. FIG. 3 shows this in a top sectional view. If there are three or more stages, the crossing angle α between the adjacent stirring blades may be less than 90 degrees.

  With this configuration, the medium is first stirred by the stirring blade disposed in the upper stage, and a downward flow is formed. Next, the flow formed by the upper stirring blade is further accelerated downward by the stirring blade disposed in the lower stage, and the downward flow is also separately formed in the stirring blade itself, and the flow is accelerated as a whole. Presumed to progress. As a result, a flow area having a large shear stress formed as a turbulent flow is formed, and it is estimated that the shape of the toner can be controlled.

  2 and 3, the arrows indicate the rotation direction, 7 indicates the upper material input port, and 8 indicates the lower material input port. Reference numeral 9 denotes a turbulent flow forming member for making stirring effective.

  Here, the shape of the stirring blade is not particularly limited, but it may be a square plate, a notch in a part of the blade, one or more holes in the center, and a so-called slit. Can be used. Examples of these are described in FIG. In FIG. 4, (a) is a stirring blade without a hole, (b) is a large hole 6 in the center, (c) is a horizontally long hole 6, (d) There is a vertically long hole 6. In addition, these may be different in the upper hole and the lower hole, or the same one may be used.

  Moreover, the example of the preferable structure which can be used as a structure of this stirring blade is shown to FIGS. FIG. 5 shows a configuration having a protrusion and / or a bent portion at the end of the stirring blade, FIG. 6 shows a configuration having a slit in the lower stirring blade and a bent portion and a projection at the end, and FIG. FIG. 8 shows a configuration in which the upper stirring blade has a gap and a lower stirring blade has a bent portion and a projection in the end of the stirring blade. FIG. 7 shows the configuration of the stirring blade in 3 Each of the stages is shown. The angle of the bent portion at the end of the stirring blade is preferably about 5 to 45 °.

  A stirring blade having a structure having a bent portion or a protrusion on the upper or lower portion effectively generates turbulent flow.

  The gap between the upper and lower stirring blades having the above-described configuration is not particularly limited, but it is preferable to have at least a gap between the stirring blades. Although the reason for this is not clear, it is considered that the stirring efficiency is improved because a medium flow is formed through the gap. However, the gap is preferably 0.5 to 50% width, more preferably 1 to 30% width with respect to the liquid surface height in the stationary state.

  Further, the size of the stirring blade is not particularly limited, but the total height of all the stirring blades is 50% to 100%, preferably 60% to 95% of the liquid surface height in the stationary state. is there.

  FIG. 9 shows an example of a stirring blade and a stirring tank used when a laminar flow is formed in the suspension polymerization method. The stirring tank is characterized in that no obstacle such as a baffle plate that forms a turbulent flow is provided. Regarding the configuration of the stirring blade, similar to the stirring blade used when forming the turbulent flow described above, the upper stirring blade is arranged with an intersecting angle α preceding the lower stirring blade in the rotational direction. It is preferable to have a multi-stage configuration.

  The shape of the stirring blade is not particularly limited as long as it does not form a turbulent flow, but is preferably formed by a continuous surface such as the rectangular plate in FIG. 4A, and has a curved surface. It may be.

  On the other hand, in a polymerization method toner that associates or fuses resin particles in an aqueous medium, by controlling the flow and temperature distribution of the medium in the reaction vessel at the fusing stage, and further in the shape control step after fusing. By controlling the heating temperature, the number of rotations of stirring, and the time, the shape distribution and shape of the entire toner can be arbitrarily changed.

  For polymerized toner that associates or fuses resin particles, the flow in the reactor is laminar, and the mixing process and shape control are performed using a stirring blade and a stirring tank that can make the internal temperature distribution uniform. By controlling the temperature, rotation speed, and time in the process, the toner having the shape factor and uniform shape distribution of the present invention can be formed. The reason for this is that if the laminar flow is fused in a place where the laminar flow is formed, strong stress is not applied to the particles (aggregation or agglomerated particles) in which aggregation and fusion proceed, and in laminar flow where the flow is accelerated As a result of the uniform temperature distribution in the stirring tank, the shape distribution of the fused particles is estimated to be uniform. Further, the fused particles gradually become spherical by heating and stirring in the subsequent shape control step, and the shape of the toner particles can be arbitrarily controlled.

  As the stirring blade and the stirring tank used in the polymerization method toner for associating or fusing the resin particles, the same one as in the case of forming a laminar flow in the suspension polymerization method described above can be used, for example, as shown in FIG. Can be used. The stirring tank is characterized in that no obstacle such as a baffle plate that forms a turbulent flow is provided. Regarding the configuration of the stirring blade, similar to the stirring blade used in the suspension polymerization method described above, the upper stirring blade is disposed with a crossing angle α preceding the lower stirring blade in the rotational direction. In addition, a multistage configuration is preferable.

  The shape of the stirring blade is not particularly limited as long as it does not form a turbulent flow as long as it can use the same laminar flow as that in the suspension polymerization method described above, but the rectangular shape in FIG. What is formed by the continuous surface, such as a plate-shaped thing, is preferable, and may have a curved surface.

  The variation coefficient of the shape factor of the toner of the present invention is calculated from the following equation.

Coefficient of variation = [S / K] x 100 (%)
In the formula, S represents the standard deviation of the shape factor of 100 toner particles, and K represents the average value of the shape factor.

  The variation coefficient of the shape factor is 16% or less, preferably 14% or less. When the variation coefficient of the shape factor is 16% or less, voids in the transferred toner layer are reduced, fixing property is improved, and offset is less likely to occur. In addition, the charge amount distribution becomes sharp and the image quality is improved.

  Toner particles that are being formed in the process of polymerizing, fusing, and controlling the shape of resin particles (polymer particles) in order to uniformly control the shape factor of the toner and the coefficient of variation of the shape factor without variation in lots. An appropriate process end time may be determined while monitoring the characteristics of the (colored particles).

  Monitoring means that a measuring device is incorporated in-line, and process conditions are controlled based on the measurement result. In other words, in the case of a polymerization method toner that is formed by incorporating measurement such as shape in-line, for example, by associating or fusing resin particles in an aqueous medium, the shape and particle size are measured while performing sequential sampling in the fusing step. The reaction is stopped when the desired shape is obtained.

  Although it does not specifically limit as a monitoring method, The flow type particle image analyzer FPIA-2000 (made by Toa Medical Electronics Co., Ltd.) can be used. This apparatus is suitable because the shape can be monitored by performing image processing in real time while passing the sample liquid. That is, a pump or the like is used from the reaction field and is constantly monitored to measure the shape and the like, and the reaction is stopped when the desired shape is obtained.

  The number particle size distribution and the number variation coefficient of the toner of the present invention are measured by a Coulter Counter TA-II or Coulter Multisizer (manufactured by Coulter Inc.). In the present invention, a Coulter Multisizer is used, and an interface (manufactured by Nikka Kisha Co., Ltd.) for outputting the particle size distribution and a personal computer are connected. The aperture used in the Coulter Multisizer was 100 μm, and the volume and number of toners of 2 μm or more were measured to calculate the particle size distribution and average particle size. The number particle size distribution represents the relative frequency of the toner particles with respect to the particle size, and the number average particle size represents the median diameter in the number particle size distribution.

  The number variation coefficient in the toner number particle size distribution is calculated from the following equation.

Number variation coefficient = (S / Dn) × 100 (%)
In the formula, S represents the standard deviation in the number particle size distribution, and Dn represents the number average particle size (μm).

  The number variation coefficient of the toner of the present invention is 27% or less, preferably 25% or less. When the number variation coefficient is 27% or less, voids in the transferred toner layer are reduced, fixing properties are improved, and offset is less likely to occur. In addition, the charge amount distribution becomes sharp, the transfer efficiency is increased, and the image quality is improved.

  The method for controlling the number variation coefficient of the present invention is not particularly limited. For example, a method of classifying toner particles by wind force can be used, but classification in a liquid is effective for reducing the number variation coefficient. As a method of classifying in this liquid, there is a method of separating and collecting toner particles according to a difference in sedimentation speed caused by a difference in toner particle diameter by using a centrifuge and controlling the rotation speed.

  In particular, when a toner is produced by a suspension polymerization method, a classification operation is indispensable in order to make the number variation coefficient in the number particle size distribution 27% or less. In the suspension polymerization method, it is necessary to disperse a polymerizable monomer in an oil droplet having a desired size as a toner in an aqueous medium before polymerization. That is, mechanical shearing with a homomixer or homogenizer is repeated for large oil droplets of a polymerizable monomer to reduce the oil droplets to the size of toner particles. In the method using shearing, the number particle size distribution of the obtained oil droplets is wide, and therefore the particle size distribution of the toner obtained by polymerizing the oil droplets is also wide. For this reason, classification operation is essential.

  The toner particles having no corners of the present invention refer to toner particles that substantially do not have projections that concentrate electric charges or projections that easily wear due to stress. Toner particles without toner. That is, as shown in FIGS. 10A, 10B, and 10C, a circle having a major axis of the toner particle L and a radius R of L / 10 is in contact with the toner particle peripheral line at one point. On the other hand, when the inside is rolled, the case where the circle does not substantially protrude outside the toner is referred to as toner particles having no corners. The case where it does not protrude substantially refers to one or less protrusions where the protruding circle exists. The major axis of the toner particles refers to the width of the particle that maximizes the interval between the parallel lines when the projected image of the toner particles on the plane is sandwiched between two parallel lines.

  The measurement of toner without corners was performed as follows. First, an enlarged photograph of the toner particles is taken with a scanning electron microscope, and further enlarged to obtain a 15,000 times photographic image. The photographic image is then measured for the presence or absence of the corners. This measurement was performed on 100 toner particles.

  In the toner of the present invention, the proportion of toner particles having no corners is 50% by number or more, preferably 70% by number or more. When the ratio of toner particles having no corners is 50% by number or more, generation of fine particles is less likely to occur due to stress with the developer conveying member, and the toner having excessive adhesion to the surface of the developer conveying member. In addition, the contamination of the developer conveying member can be suppressed, and the charge amount can be sharpened. In addition, toner particles that easily wear and break and toner particles having a portion where charges are concentrated are reduced, the charge amount distribution becomes sharp, the chargeability is stable, and good image quality can be formed over a long period of time.

  A method for obtaining toner having no corners is not particularly limited. For example, as described above as a method for controlling the shape factor, a method in which toner particles are sprayed into a hot air stream, a method in which toner particles are repeatedly applied with mechanical energy by impact force in a gas phase, or a toner is dissolved. It can be obtained by adding in a solvent that does not, and applying a swirling flow.

  Further, in the polymerization toner formed by associating or fusing the resin particles, the fusing particle surface has many irregularities at the fusing stop stage, and the surface is not smooth, but the temperature in the shape control step, By making the conditions such as the number of revolutions of the stirring blade and the stirring time appropriate, a toner having no corners can be obtained. These conditions vary depending on the physical properties of the resin particles. For example, by setting the rotational speed to be higher than the glass transition temperature of the resin particles, the toner can be formed with a smooth surface and no corners.

  The toner of the present invention preferably has a number average particle diameter of 3 to 8 μm. When the toner particles are formed by a polymerization method, the particle size can be controlled by the concentration of the aggregating agent, the amount of the organic solvent added, the fusing time, and further the composition of the polymer itself.

  When the number average particle diameter is 3 to 8 μm, it is possible to reduce the presence of toner having excessive adhesion to the developer conveying member or toner having low adhesion force in the fixing process, and developability over a long period of time. And the transfer efficiency is increased, the image quality of halftone is improved, and the image quality of fine lines and dots is improved.

  As the toner of the present invention, when the particle size of the toner particle is D (μm), the natural logarithm lnD is taken on the horizontal axis, and the number-based particle size distribution is divided into a plurality of classes at intervals of 0.23. In the histogram shown, the sum (M) of the relative frequency (m1) of the toner particles included in the most frequent class and the relative frequency (m2) of the toner particles included in the next most frequent class after the most frequent class is 70. % Of the toner is preferable. When the sum (M) of the relative frequency (m1) and the relative frequency (m2) is 70% or more, the dispersion of the particle size distribution of the toner particles becomes narrow. Therefore, selective development can be performed by using the toner in the image forming process. Can be reliably suppressed.

  In the present invention, the histogram showing the particle size distribution based on the number is a natural logarithm lnD (D: particle size of individual toner particles) having a plurality of classes (0 to 0.23: 0.23) at intervals of 0.23. 0.46: 0.46-0.69: 0.69-0.92: 0.92-1.15: 1.15-1.38: 1.38-1.61: 1.61-1. 84: 1.84 to 2.07: 2.07 to 2.30: 2.30 to 2.53: 2.53 to 2.76, and so on). This histogram was created by transferring the particle size data of the sample measured by the Coulter Multisizer to the computer via the I / O unit according to the following conditions and using the particle size distribution analysis program in the computer. is there.

Measurement conditions (1) Aperture: 100 μm
(2) Sample preparation method: Electrolyte [ISOTON R-11 (manufactured by Coulter Scientific Japan)] 50-100 ml, an appropriate amount of a surfactant (neutral detergent) is added and stirred, and 10-20 mg of a measurement sample is added thereto. Add This system is prepared by dispersing for 1 minute with an ultrasonic disperser.

  In addition, the toner of the present invention can be more effective by adding and using fine particles such as inorganic fine particles and organic fine particles as external additives. The reason for this is presumed that the effect can be conspicuous because the burying and detachment of the external additive can be effectively suppressed.

  As the inorganic fine particles, inorganic oxide particles such as silica, titania, and alumina are preferably used, and these inorganic fine particles are preferably hydrophobized with a silane coupling agent or a titanium coupling agent. The degree of the hydrophobizing treatment is not particularly limited, but a methanol wettability of 40 to 95 is preferable. Methanol wettability is an evaluation of wettability to methanol. In this method, 0.2 g of inorganic fine particles to be measured is weighed and added to 50 ml of distilled water in a 200 ml beaker. Methanol is slowly dropped from a burette whose tip is immersed in a liquid, with slow stirring until the entire inorganic fine particles are wet. When the amount of methanol necessary to completely wet the inorganic fine particles is a (ml), the degree of hydrophobicity is calculated by the following formula.

Hydrophobicity = (a / (a + 50)) × 100
The addition amount of the external additive is 0.1 to 5.0% by mass, preferably 0.5 to 4.0% by mass in the toner. In addition, various external additives may be used in combination.

  Next, as for numerical values according to the present invention, conventionally known numerical values of toner will be described. This value varies depending on the manufacturing method.

  In the case of pulverized toner, the proportion of toner particles having a shape factor of 1.2 to 1.6 is about 60% by number. The variation coefficient of the shape factor of this is about 20%. Further, in the pulverization method, in order to reduce the particle size while repeating the crushing, the toner particles have more corners, and the proportion of toner particles without corners is 30% by number or less. Therefore, in order to obtain a rounded toner with uniform shapes and no corners, a process for spheroidizing with heat or the like as described above is required as a method for controlling the shape factor. In addition, the number variation coefficient in the number particle size distribution is about 30% when the classification operation after pulverization is one time, and in order to make the number variation coefficient 27% or less, it is necessary to repeat the classification operation. There is.

  In the case of a toner by suspension polymerization, since it is conventionally polymerized in a laminar flow, substantially spherical toner particles are obtained. For example, in the toner described in JP-A-56-130762, the shape factor is 1 The ratio of toner particles having a diameter of 2 to 1.6 is about 20% by number, the coefficient of variation of the shape factor is about 18%, and the ratio of toner particles without corners is about 85% by number. In addition, as described above in the method for controlling the number variation coefficient in the number particle size distribution, mechanical shearing is repeatedly performed on large oil droplets of the polymerizable monomer to reduce the oil droplets to the size of toner particles. Therefore, the distribution of the oil droplet diameter is widened, and therefore, the particle size distribution of the obtained toner is wide and the number variation coefficient is as large as about 32%. To reduce the number variation coefficient, the technique described in the above publication is used. If the toner is produced based on the classification, a classification operation is required.

  In the polymerization method toner formed by associating or fusing resin particles, for example, in the toner described in JP-A-63-186253, the ratio of toner particles having a shape factor of 1.2 to 1.6 Is about 60% by number, the coefficient of variation of the shape factor is about 18%, and the proportion of toner particles without corners is about 44% by number. Further, the particle size distribution of the toner is wide, the number variation coefficient is 30%, and classification operation is necessary to reduce the number variation coefficient.

  The developing methods in which the toner of the present invention can be used are shown below.

  A developing device used in the image forming apparatus of the present invention will be described. The developing device used in the present invention includes a toner conveying member, a toner layer regulating member, and a toner replenishing auxiliary member, and the toner replenishing auxiliary member and the toner conveying member, and the toner layer regulating member and the toner conveying member are in contact with each other. It is. In this system, the non-magnetic toner thinned using the apparatus is supplied to the surface of the electrostatic latent image forming body to develop the latent image.

  The toner conveying member supplies non-magnetic one-component toner to the electrostatic latent image forming body. This member is preferably a member having elasticity in order to ensure a sufficient development region by its elasticity in a state where it is in contact with the electrostatic latent image forming body.

  In the present invention, a roller of urethane rubber or silicone rubber, a nickel endless belt-like member including a sponge roller, or the like can be used as the toner conveying member.

  The toner layer regulating member has a function of uniformly applying toner to the toner conveying member and imparting frictional charging. In this case, an elastic body such as urethane rubber or a metal plate is used, and a thin layer of toner is formed on the toner conveying member by contacting the elastic body with the toner conveying member. The thinned layer is a layer formed by overlapping a maximum of 10 toner layers, preferably 5 layers or less, in the development region. The toner layer regulating member is preferably in contact with the toner conveying member at a pressure of 0.1 N / cm to 5.0 N / cm. More preferably, it is 0.2-4.0 N / cm. When this pressure is less than 0.1 N / cm, toner conveyance is non-uniform, uneven conveyance is likely to occur, and white streaks are likely to occur on the image. The toner conveying member preferably has a diameter of 10 to 50 mm.

  The toner replenishing auxiliary member is a unit for stably supplying toner to the toner conveying member. As this, a water wheel-like roller with a stirring blade or a sponge-like roller can be used. This preferably has a diameter in the range of 0.2 to 1.5 times that of the toner conveying member. If the diameter is too small, the toner supply is insufficient, and if it is too large, the toner supply is excessive, and the toner supply is not stabilized, and streaky image defects are likely to occur.

  The electrostatic latent image forming member is typically an electrophotographic photosensitive member. Specific examples include inorganic photoreceptors such as selenium and arsenic selenium, amorphous silicon photoreceptors, and organic photoreceptors. Particularly preferred is an organic photoreceptor having a laminated structure of a charge transport layer and a charge generation layer.

  Hereinafter, the developing device of the image forming method of the present invention will be specifically described.

  Next, FIG. 11 is a schematic sectional view of the developing device of the image forming method of the present invention.

  In FIG. 11, the non-magnetic one-component toner 16 built in the toner tank 17 is forcibly conveyed and supplied onto the sponge roller 14 as the toner replenishment auxiliary member by the stirring blade 15 as the toner replenishment auxiliary member. The toner thus incorporated on the sponge roller is conveyed onto the rubber roller 12 as a toner conveying member by the rotation of the roller 14 in the direction of the arrow, and electrostatically and physically on the surface by friction with the roller 12. Adsorbed. On the other hand, the toner adhering to the rubber roller 12 is uniformly thinned and frictionally charged by the rotation of the roller 12 in the arrow direction and the steel elastic blade 13 as a toner layer thickness regulating member. Next, the latent image is developed on the toner thin layer on the rubber roller 12 by contact or proximity to the surface of the electrophotographic photosensitive drum 11 as an electrostatic latent image carrier.

  Needless to say, the developing device used in the method of the present invention is not limited to that shown in FIG.

  A preferred fixing method used in the present invention is a so-called contact heating method. In particular, examples of the contact heating method include a heat pressure fixing method, a heat roller fixing method, and a pressure heating fixing method in which fixing is performed by a rotating pressure member including a fixedly arranged heating body.

  In the hot roll fixing method, in many cases, an upper roller having a heat source inside a metal cylinder composed of iron, aluminum or the like whose surface is coated with tetrafluoroethylene or polytetrafluoroethylene-perfluoroalkoxy vinyl ether copolymers, etc. And a lower roller made of silicone rubber or the like. A typical example of the heat source is one having a linear heater and heating the surface temperature of the upper roller to about 120 to 200 ° C. In the fixing unit, pressure is applied between the upper roller and the lower roller to deform the lower roller to form a so-called nip. The nip width is 1 to 10 mm, preferably 1.5 to 7 mm. The fixing linear velocity is preferably 40 mm / sec to 600 mm / sec. If the nip is narrow, heat cannot be uniformly applied to the toner, and uneven fixing occurs. On the other hand, when the nip width is wide, the melting of the resin is promoted, and the problem of excessive fixing offset occurs.

  A fixing cleaning mechanism may be provided for use. As this method, a method of supplying silicone oil to the upper roller or film for fixing, or a method of cleaning with a pad, roller, web or the like impregnated with silicone oil can be used.

  Next, a method for fixing by a rotating pressure member including a fixedly arranged heating body used in the present invention will be described.

  This fixing method is a method in which pressure fixing is performed by a fixedly arranged heating body and a pressure member that is in pressure-contact with the heating body and that closely contacts the recording material with the heating body through a film.

  In this press-contact fixing device, the heating body has a smaller heat capacity than a conventional heating roller, and has a line-shaped heating section in a direction perpendicular to the passing direction of the recording material. 300 ° C.

  Note that pressure contact fixing is a method in which an unfixed toner image is pressed against a heating source, such as a method in which a recording material with unfixed toner is passed between a heating member and a pressure member, as is usually used. is there. In this way, since heating is performed quickly, the fixing speed can be increased. However, temperature control is difficult, and the toner remains attached to a portion directly pressed against unfixed toner such as a surface portion of the heating source. There are also problems that toner offset is likely to occur, and that the recording material is likely to break down such as winding around the fixing device.

  Next, embodiments of the present invention will be described with reference to examples, but the present invention is of course not limited to these embodiments.

(Toner Production Example 1: Example of emulsion polymerization association method)
Add 0.90 kg of sodium n-dodecyl sulfate and 10.0 L of pure water and dissolve with stirring. To this solution, 1.20 kg of Legal 330R (Cabot Black Carbon Black) was gradually added and stirred well for 1 hour, followed by continuous dispersion for 20 hours using a sand grinder (medium disperser). This is referred to as “colorant dispersion 1”. A solution composed of 0.055 kg of sodium dodecylbenzenesulfonate and 4.0 L of ion-exchanged water is referred to as “anionic surfactant solution A”.

  A solution composed of 0.014 kg of nonylphenol polyethylene oxide 10 mol adduct and 4.0 L of ion-exchanged water is referred to as “nonionic surfactant solution B”. A solution obtained by dissolving 223.8 g of potassium persulfate in 12.0 L of ion-exchanged water is referred to as “initiator solution C”.

  To a 100 L GL (glass lining) reaction kettle equipped with a temperature sensor, a cooling pipe, and a nitrogen introducing device, a WAX emulsion (a polypropylene emulsion having a number average molecular weight of 3000: number average primary particle size = 120 nm / solid content concentration = 29.9%) ) Put 3.41 kg, the total amount of “anionic surfactant solution A” and the total amount of “nonionic surfactant solution B”, and start stirring. The configuration of the stirring blade was the configuration shown in FIG. The angle and overall size of the stirring blade are shown in the attached table. Then, 44.0 L of ion exchange water is added.

  Heating was started and when the liquid temperature reached 75 ° C., the entire amount of “Initiator Solution C” was added dropwise. Thereafter, while controlling the liquid temperature to 75 ° C. ± 1 ° C., 12.1 kg of styrene, 2.88 kg of n-butyl acrylate, 1.04 kg of methacrylic acid, and 548 g of t-dodecyl mercaptan are added dropwise. After completion of the dropwise addition, the liquid temperature was raised to 80 ° C. ± 1 ° C. and stirring was performed for 6 hours. Next, the liquid temperature is cooled to 40 ° C. or lower, stirring is stopped, and the mixture is filtered through a pole filter, which is designated as “Latex 1-A”.

  The glass transition temperature of the resin particles in the latex 1-A was 57 ° C., the softening point was 121 ° C., the molecular weight distribution was weight average molecular weight = 17,000, and the mass average particle size was 120 nm.

  A solution obtained by dissolving 0.055 kg of sodium dodecylbenzenesulfonate in 4.0 L of ion-exchanged pure water is referred to as “anionic surfactant solution D”. Further, a solution obtained by dissolving 0.014 kg of nonylphenol polyethylene oxide 10 mol adduct in 4.0 L of ion-exchanged water is referred to as “nonionic surfactant solution E”.

  A solution obtained by dissolving 200.7 g of potassium persulfate (manufactured by Kanto Chemical Co., Ltd.) in 12.0 L of ion-exchanged water is referred to as “initiator solution F”.

  The structure of the stirring blade of a 100 L GL reaction kettle equipped with a temperature sensor, a cooling pipe, a nitrogen introducing device, and a comb-shaped baffle is shown in FIG. 4A, WAX emulsion (polypropylene emulsion having a number average molecular weight of 3000: number average primary particle size = 120 nm / solid content concentration 29.9%) 3.41 kg, the total amount of “anionic surfactant solution D” and the total amount of “nonionic surfactant solution E” are added, and stirring is started. Next, 44.0 L of ion exchange water is added. Heating is started, and when the liquid temperature reaches 70 ° C., “initiator solution F” is added. Next, a solution prepared by previously mixing 11.0 kg of styrene, 4.00 kg of n-butyl acrylate, 1.04 kg of methacrylic acid, and 9.02 g of t-dodecyl mercaptan is dropped. After completion of the dropwise addition, the liquid temperature was controlled at 72 ° C. ± 2 ° C., and the mixture was heated and stirred for 6 hours. Furthermore, the liquid temperature was raised to 80 ° C. ± 2 ° C., and the mixture was heated and stirred for 12 hours. The liquid temperature is cooled to 40 ° C. or lower and stirring is stopped. It filtered with the pole filter and this filtrate was set to "latex 1-B."

  The glass transition temperature of the resin particles in the latex 1-B was 58 ° C., the softening point was 132 ° C., the molecular weight distribution was weight average molecular weight = 245,000, and the mass average particle size was 110 nm.

  A solution obtained by dissolving 5.36 kg of sodium chloride as a salting-out agent in 20.0 L of ion-exchanged water is referred to as “sodium chloride solution G”.

  A solution obtained by dissolving 1.00 g of a fluorine-based nonionic surfactant in 1.00 L of ion-exchanged water is referred to as “nonionic surfactant solution H”.

  In a 100 L SUS reaction kettle equipped with a temperature sensor, a cooling pipe, a nitrogen introduction device, and a particle size and shape monitoring device (the configuration of the stirring blade is FIG. 4A), the latex 1-A = 20. 0 kg, latex 1-B = 5.2 kg, colorant dispersion 1 = 0.4 kg and ion-exchanged water 20.0 kg are added and stirred. Next, the mixture is heated to 40 ° C., and sodium chloride solution G, isopropanol (manufactured by Kanto Chemical Co.) 6.00 kg, and nonionic surfactant solution H are added in this order. Then, after standing for 10 minutes, the temperature rise was started, the temperature was raised to a liquid temperature of 85 ° C. in 60 minutes, and the particles were heated and stirred at 85 ± 2 ° C. for 0.5 to 3 hours while being salted out / fused. Grow. Next, 2.1 L of pure water is added to stop the particle size growth.

  In a 5 L reaction vessel equipped with a temperature sensor, a cooling pipe, a particle size and shape monitoring device (the configuration of the stirring blade is FIG. 9), 5.0 kg of the fused particle dispersion prepared above was placed, and the liquid temperature was 85 ° C. The shape was controlled by heating and stirring at ± 2 ° C. for 0.5 to 15 hours. Then, it cools to 40 degrees C or less and stops stirring. Next, using a centrifugal separator, classification is performed in the liquid by a centrifugal sedimentation method, followed by filtration with a sieve having an opening of 45 μm. Subsequently, wet cake-like non-spherical particles were collected from the association liquid 1 by using a Nutsche. Thereafter, it was washed with ion exchange water.

  The non-spherical particles were dried at a suction air temperature of 60 ° C. using a flash jet dryer and then dried at a temperature of 60 ° C. using a fluidized bed dryer. To 100 parts by mass of the obtained colored particles, 1 part by mass of silica fine particles was externally added and mixed with a Henschel mixer to obtain a toner by an emulsion polymerization association method.

  In the monitoring of the salting-out / fusion stage and the shape control process, by controlling the number of revolutions of stirring and the heating time, the coefficient of variation of the shape and the shape factor is controlled, and further the particle size and particle size distribution by subclassification in the liquid. Were arbitrarily adjusted to obtain toners 1 to 50 shown in Tables 1 to 3.

(Toner production example 2: Example of emulsion polymerization association method)
Toner 51 to 59 shown in Table 3 were obtained in the same manner as in Toner Production Example 1 except that 1.05 kg of benzidine yellow pigment was used instead of carbon black as the colorant.

(Toner production example 3: Example of emulsion polymerization association method)
Toners 60 to 68 shown in Tables 3 to 4 were obtained in the same manner as in Toner Production Example 1 except that 1.20 kg of quinacridone-based magenta pigment was used instead of carbon black.

(Toner Production Example 4: Example of Emulsion Polymerization Association Method)
Toners 69 to 77 shown in Table 4 were obtained in the same manner as in Toner Production Example 1, except that 0.60 kg of phthalocyanine cyan pigment was used instead of carbon black as the colorant.

(Toner Production Example 5: Example of suspension polymerization method)
165 g of styrene, 35 g of n-butyl acrylate, 10 g of carbon black, 2 g of di-t-butyl salicylic acid metal compound, 8 g of styrene-methacrylic acid copolymer and 20 g of paraffin wax (mp = 70 ° C.) are heated to 60 ° C. A homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) was uniformly dissolved and dispersed at 12000 rpm. To this, 10 g of 2,2′-azobis (2,4-valeronitrile) was added as a polymerization initiator and dissolved, followed by polymerization. A functional monomer composition was prepared. Next, 450 g of 0.1 M sodium phosphate aqueous solution was added to 710 g of ion exchange water, and 68 g of 1.0 M calcium chloride was gradually added while stirring at 13,000 rpm with a TK homomixer to prepare a suspension in which tricalcium phosphate was dispersed. did. The polymerizable monomer composition was added to this suspension, and stirred at 10,000 rpm for 20 minutes with a TK homomixer to granulate the polymerizable monomer composition. Then, using the reaction apparatus which made the structure of the stirring blade the FIG. 2, it was made to react at 75-95 degreeC for 5 to 15 hours. Tricalcium phosphate was dissolved and removed with hydrochloric acid, and then classified in a liquid by centrifugal sedimentation using a centrifugal separator, and then filtered, washed and dried. To 100 parts by mass of the obtained colored particles, 1 part by mass of silica fine particles was externally added and mixed with a Henschel mixer to obtain a toner by suspension polymerization.

  Monitoring is performed during the polymerization, and the variation coefficient of the shape and shape factor is controlled by controlling the liquid temperature, the number of rotations of stirring, and the heating time. Furthermore, the variation coefficient of the particle size and particle size distribution is arbitrarily determined by classification in the liquid. The toners 78 to 83 shown in Tables 4 to 5 were obtained.

(Toner Production Example 6: Example of suspension polymerization method)
In Toner Production Example 5, a toner 84 shown in Table 5 was obtained in the same manner except that the configuration of the stirring blade was changed to that shown in FIG. 9 and that the classification in the liquid using a centrifuge was not performed.

(Toner Production Example 7: Example of grinding method)
A toner raw material consisting of 100 kg of styrene-nbutyl acrylate copolymer resin, 10 kg of carbon black and 4 parts by mass of polypropylene is premixed with a Henschel mixer, melt kneaded with a twin screw extruder, and coarsely pulverized with a hammer mill. The resulting powder was pulverized by a jet pulverizer, and the obtained powder was dispersed in a hot air stream of a spray dryer (at 200 to 300 ° C. for 0.05 seconds) to obtain particles whose shape was adjusted. These particles were repeatedly classified with an air classifier until the desired particle size distribution was obtained. To 100 parts by mass of the obtained colored particles, 1 part by mass of silica fine particles was externally added and mixed with a Henschel mixer to obtain toners 85 to 88 shown in Table 5 by a pulverization method.

  In this way, toners shown in Tables 1 to 5 below were obtained in which the variation coefficient of the shape and the shape factor was controlled and the variation coefficient of the particle size and the particle size distribution was adjusted.

Evaluation A digital copying machine Konica 7033 manufactured by Konica was modified and an image was formed using the developing device shown in FIG.

  As the developing unit, a toner conveying member made of a 25 mm silicon rubber roller was used, and the diameter of the toner replenishing auxiliary member was 20 mm. The toner layer regulating member is made of urethane rubber, and the contact pressure is 0.6 N / cm. The copy speed was changed to A4, 20 sheets / minute (ppm), and a live-action evaluation was performed. As the photoconductor, a laminated organic photoconductor was used. Further, a method of cleaning the untransferred toner remaining on the photoreceptor by a blade cleaning method was adopted.

  As a recording material to be used, a sheet having a continuous weight of 55 kg was used, and an image was formed in the vertical direction.

  Further, as image forming conditions, a line drawing having a pixel rate of 5% was used in a high temperature and high humidity environment (30 ° C., 85% RH), and 50,000 sheets were printed by a single sheet intermittent printing method. The initial image and the image after 50000 sheets were evaluated. As the image, a solid black, a halftone image, and a solid white image were printed, and the image density, fog density, and presence / absence of unevenness of the halftone image were evaluated. For the image density, RD-918 manufactured by Macbeth Co. was used, and the absolute reflection density was measured. The fog density was measured at a relative reflection density where the reflection density of the paper was “0”. Further, the halftone uniformity was judged visually, and the uniformity of the halftone image was evaluated. The rank was evaluated as follows.

Rank A: Uniform image without unevenness Rank B: Existence of thin uneven stripes Rank C: Existence of several thin uneven stripes Rank D: Existence of several uneven lines of unevenness Pressure contact as a fixing device A heat fixing device of the type was adopted. The configuration is as follows.

  It has an upper roller made of columnar iron with a 30 mm diameter heater coated in the center with a surface coated with a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, and the surface is similarly tetrafluoroethylene-perfluoroalkyl ether It has a lower roller 30 mm in diameter composed of silicone rubber coated with a copolymer. The linear pressure was set to 8.0 N / cm, and the nip width was 4.3 mm. Using this fixing device, the linear speed of printing was set to 250 mm / sec. The fixing temperature was controlled by the surface temperature of the upper roll, and was set to a set temperature of 185 ° C. Note that a web-type supply system impregnated with polydiphenyl silicone (having a viscosity of 10 Pa · s at 20 ° C.) was used as a cleaning mechanism of the fixing device.

  As described above, according to the image formation performed, it can be seen that all the examples in the present invention have characteristics that can be put into practical use. However, the comparative example outside the present invention has a problem in at least one of the characteristics.

The perspective view of an example of the stirring tank provided with the conventional stirring blade. The perspective view of an example of the stirring tank provided with the stirring blade of this invention. FIG. 3 is a top sectional view of FIG. 2. The outline figure of the shape of a stirring blade. The perspective view of an example of the stirring tank provided with the stirring blade of this invention. The perspective view of an example of the stirring tank provided with the stirring blade of this invention. The perspective view of an example of the stirring tank provided with the stirring blade of this invention. The perspective view of an example of the stirring tank provided with the stirring blade of this invention. The perspective view of an example of the stirring tank provided with the stirring blade of this invention. Schematic illustrating toner particles without corners. 1 is a schematic cross-sectional view showing an example of a developing device used for an electrostatic latent image developing method in the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat exchange jacket 2 Stirrer tank 3 Rotating shaft 4 Lower stirrer blade 5 Upper stirrer blade 6 Middle hole 11 Electrostatic latent image carrier (electrophotographic photosensitive drum)
12 Toner conveying member (rubber roller)
13 Toner layer thickness regulating member (steel elastic blade)
14, 15 Toner replenishment auxiliary member (roller with stirring blade and sponge roller)
16 Non-magnetic one-component toner 17 Toner tank

Claims (8)

The developing device is provided with a toner conveying member, a toner layer regulating member, and a toner replenishing auxiliary member, and is thinned using a developing device in which the toner replenishing auxiliary member and the toner conveying member are in contact with each other. In the non-magnetic one-component electrostatic latent image developing method in which the non-magnetic toner is supplied to the surface of the electrostatic latent image forming body to develop the latent image, the toner polymerizes at least a polymerizable monomer in an aqueous medium. and made by associating the resulting resin particles in an aqueous medium, it is no angular toner particles 50% by number or more in the following measurement method, and wherein the number variation coefficient in the number particle size distribution is not more than 27% A non-magnetic one-component electrostatic latent image developing method.
(Measurement method)
When the inner diameter of the toner particle is a circle having a major axis L and L / 10 is a radius R, and the inner side of the toner particle is in contact with the inner circumference of the toner particle at one point, the circle is substantially outside the toner. The case where it does not start is called toner particles having no corners. The case where it does not protrude substantially refers to one or less protrusions where the protruding circle exists. The major axis of the toner particles refers to the width of the particle that maximizes the interval between the parallel lines when the projected image of the toner particles on the plane is sandwiched between two parallel lines.
To measure the toner having no corners, first, a photograph in which the toner particles are enlarged is taken with a scanning electron microscope, and further enlarged to obtain a 15,000 times photographic image. The photographic image is then measured for the presence or absence of the corners. This measurement is performed on 100 toner particles. An image forming method comprising the steps of forming a latent image, developing, transferring, and fixing using the nonmagnetic one-component electrostatic latent image developing method according to claim 1. 3. The image forming method according to claim 2, wherein the toner used contains 65% by number or more of toner particles having a shape factor in the range of 1.0 to 1.6. 3. The image forming method according to claim 2, wherein the toner used contains 65% by number or more of toner particles having a shape factor in the range of 1.2 to 1.6. The image forming method according to claim 2, 3 or 4, wherein the toner used has a number average particle diameter of 3 to 8 µm. When the particle size of the toner particles used is D (μm), the natural logarithm lnD is taken on the horizontal axis, and the horizontal axis is a histogram showing the number-based particle size distribution divided into a plurality of classes at intervals of 0.23. The sum (M) of the relative frequency (m1) of toner particles contained in the most frequent class and the relative frequency (m2) of toner particles contained in the next most frequent class after the most frequent class is 70% or more. The image forming method according to claim 2, wherein the image forming method is an image forming method. An image forming apparatus comprising the steps of forming a latent image, developing, transferring, and fixing using the nonmagnetic one-component electrostatic latent image developing method according to claim 1 . The developing device is provided with a toner conveying member, a toner layer regulating member, and a toner replenishing auxiliary member, and is thinned using a developing device in which the toner replenishing auxiliary member and the toner conveying member are in contact with each other. In the toner used in the nonmagnetic one-component electrostatic latent image developing method for developing the latent image by supplying the nonmagnetic toner to the surface of the electrostatic latent image forming body, the toner contains at least a polymerizable monomer in an aqueous medium. The number of toner particles having no corners in the following measurement method is 50% by number or more, and the number variation coefficient in the number particle size distribution is 27% or less. Toner characterized by the above.
(Measurement method)
When the inner diameter of the toner particle is a circle having a major axis L and L / 10 is a radius R, and the inner side of the toner particle is in contact with the inner circumference of the toner particle at one point, the circle is substantially outside the toner. The case where it does not start is called toner particles without corners. The case where it does not protrude substantially refers to one or less protrusions where the protruding circle exists. The major axis of the toner particles refers to the width of the particle that maximizes the interval between the parallel lines when the projected image of the toner particles on the plane is sandwiched between two parallel lines.
  To measure the toner having no corners, first, a photograph in which the toner particles are enlarged is taken with a scanning electron microscope, and further enlarged to obtain a 15,000 times photographic image. The photographic image is then measured for the presence or absence of the corners. This measurement is performed on 100 toner particles.

Images