JP2006349898A - Toner and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner which satisfies high speed, high image quality, high durability, low environmental load, adaptation to various media and high environmental stability. <P>SOLUTION: The toner is obtained by preparing, in an aqueous medium, a composition containing at least a binder resin, a colorant and a release agent, wherein the binder resin is a styrene polymer, a styrene/acrylate copolymer or a mixture of those. The toner contains 0-10 mass% of a THF-insoluble component, a THF-soluble component of the toner has a weight average molecular weight (Mw1) of 5,000-100,000, the toner contains 20-50 mass% of a component soluble in a 1:1 mixed solvent of acetone/isopropyl alcohol, the component soluble in the mixed solvent has a weight average molecular weight (Mw2) of 2,000-15,000, and the Mw1 and Mw2 satisfy a relationship of 2<Mw1/Mw2<15. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to toner and image formation used in an image forming apparatus such as an electrophotographic system or an electrostatic recording system in which a developer is attached to a latent image formed on an image carrier for visualization. It is about the method.

  We do not know that the demand for higher functionality such as high image quality, higher durability, or further reduction of environmental load in electrophotography will stop, and the development of new technologies that satisfy them will not stop. For example, intermediate transfer technology that enables printing on various media (Patent Document 1, etc.), contact charging technology that suppresses the generation of ozone (Patent Document 2, etc.), and cleanerless system that suppresses the generation of waste toner (Patent) Document 3 etc.) or cleaning recovery toner recycling technology (Patent Document 4 etc.), fixing technology not using oil or cleaning web (Patent Document 5 etc.), etc.

  In particular, in the development process, a color non-magnetic one-component contact development method has been widely studied from the viewpoint of toner scattering and adhesion (for example, Patent Document 6).

  Further, recent copiers and printers are increasingly required to be smaller, lighter, and more reliable, and demands on toner performance are becoming stricter. For example, there is a need for a toner having excellent durability that is less susceptible to filming on a photoreceptor and contamination of the surface of a toner carrier such as a carrier or a sleeve without impairing low-temperature fixability and offset resistance.

  In order to achieve such a demand, many proposals have been made that define the physical properties of the toner, particularly the molecular weight.

  Patent Document 7 proposes a toner obtained by a suspension polymerization method in which the molecular weight distribution has a plurality of peaks, and when the minimum molecular weight peak position is 50,000 or less, the maximum molecular weight peak position is 200,000 or more. ing. However, further improvement is currently required from the viewpoint of low-temperature fixability.

  In Patent Document 8, GPC has a peak Mp1 in a region having a molecular weight of 500 to 2,000, a peak Mp2 in a region having a molecular weight of 10,000 to 100,000, and a weight average molecular weight (Mw) of 10, A color toner having a number average molecular weight (Mn) of 1,500 to 8,000 and a Mw / Mn ratio of 3 or more has been proposed. In this case, it is possible to obtain a color toner that is excellent in offset resistance and has a high chroma and a clear color image, but without damaging the low-temperature fixability, There is a need to develop a toner that is less likely to contaminate the surface of a toner carrier such as a carrier or a sleeve.

  In addition, regarding the molecular weight distribution of the toner, Patent Documents 9 to 14 disclose toners having excellent fixability and development stability. However, improvements have been made in various image forming methods. From the viewpoint of providing a uniform image without uneven glossiness, further improvement is required at present.

  As described above, there is no toner that can solve various problems.

JP-A-5-61385 Japanese Patent Laid-Open No. 5-119580 JP-A-5-224435 JP-A-8-69177 JP-A-9-292820 JP 2003-207921 A Japanese Patent Laid-Open No. 3-251853 JP-A-3-39971 JP-A-4-356057 JP-A-7-84380 Japanese Patent Laid-Open No. 9-230630 Japanese Patent Laid-Open No. 9-50150 JP-A-10-333359 JP 2000-56511 A

  In view of the above circumstances, an object of the present invention is to provide a toner and an image forming method that satisfy high speed, high image quality, high durability, and high environmental stability.

The above object is achieved by the present invention described below. That is, in the present invention, the binder resin is a styrene polymer, a styrene / acrylate copolymer, or a mixture thereof.
The toner has a THF insoluble content of 0 to 10% by mass,
The toner has a THF-soluble component weight average molecular weight (Mw1) of 5,000 to 100,000.
The toner has a soluble component in an acetone / isopropyl alcohol 1: 1 mixed solvent of 20 to 50% by mass, and a weight average molecular weight (Mw2) of the soluble component in the mixed solvent is 2000 to 15000.
The present invention relates to a toner characterized in that Mw1 and Mw2 satisfy a relationship of 2 <Mw1 / Mw2 <15.

  According to the present invention, it is possible to obtain a developer which is excellent in suppressing toner deterioration and excellent in suppressing member contamination.

  According to the present invention, a developer excellent in development stability and transferability can be obtained.

  Furthermore, according to the present invention, it is possible to obtain a developer excellent in low-temperature fixability and high-temperature offset resistance even in a fixing device configuration having a low heat capacity.

  Furthermore, according to the present invention, a developer with little change in gloss (glossiness) in an image can be obtained even in a fixing device configuration having a low heat capacity.

The present invention is a toner obtained by producing a composition containing at least a colorant and a release agent in an aqueous medium,
The binder resin is a styrene polymer, a styrene / acrylate copolymer or a mixture thereof,
1) The THF-insoluble content is 0 to 10% by mass, and the weight-average molecular weight (Mw1) of the THF-soluble content of the toner is 5000 to 100,000.
2) A soluble content of the toner in a 1: 1 mixed solvent of acetone / isopropyl alcohol is 20 to 50% by mass, and a weight average molecular weight (Mw2) of the soluble content in the mixed solvent is 2000 to 15000, Mw1 and Mw2 satisfy the relationship 2 <Mw1 / Mw2 <15.
The toner is characterized by the above.

  In the present invention, regarding the toner to be used, the above-mentioned items 1) and 2) are satisfied at the same time, so that the chargeability and transferability are good in various situations from a low temperature and low humidity environment to a high temperature and high humidity environment, and pictorial. In addition, while achieving color reproducibility and high gloss capable of reproducing a clear image, good results such as low-temperature fixability and high-temperature offset resistance can be obtained.

In the present invention, first, it is necessary that 1) the THF-insoluble content is 0 to 10% by mass, and the weight-average molecular weight (Mw1) of the THF-soluble content of the toner is 5000 to 100,000.

  The main resin component of the toner can be extracted with THF except for the strong cross-linking component and occupies most of the toner component. Therefore, the molecular weight design of this component is important. When the weight-average molecular weight (Mw1) of the THF soluble part of the toner is 5000 to 100,000, there is a polymer soluble in a good solvent in the fixability in a high-speed machine of a light pressure fixing device, and the molecular weight is specified. Therefore, good gloss stability and high-temperature offset resistance are achieved.

  In addition, high image quality that vividly reproduces all solid areas and highlight areas, high durability with little deterioration even after printing many sheets, high environmental stability that guarantees image quality from low temperature and low humidity environments to high temperature and high humidity environments, etc. , Can make images with excellent performance.

  If the weight-average molecular weight (Mw1) of the THF soluble part of the toner is less than 5000, problems are unlikely to occur in the normal mode, but offset tends to occur when fixing with a sufficient amount of heat such as a high gloss mode. .

  Even if the weight-average molecular weight (Mw1) of the THF soluble part of the toner exceeds 100,000, it is usually difficult to cause a problem, but a sufficient amount of heat is not applied to print a large number of sheets at a high temperature in a low temperature environment. In some cases, such as when using rough paper with a roughened surface, fixing to the paper tends to be insufficient.

<Method for measuring molecular weight distribution of THF-soluble matter>
A sample for GPC measurement is prepared as follows.

  The binder resin is placed in tetrahydrofuran (THF) and allowed to stand for several hours, then shaken well and mixed well with THF (until the resin is no longer united), and allowed to stand for an additional 12 hours. At this time, the standing time in THF is set to be 24 hours or longer. Thereafter, a sample processing filter (pore size 0.45 to 0.5 μm, for example, Mysori Disc H-25-5 manufactured by Tosoh Corporation, Excro Disc 25CR manufactured by Gelman Science Japan Co., Ltd., etc.) can be used. A sample of GPC is used. The resin concentration is adjusted so that the resin component is 0.5 to 5 mg / ml.

The molecular weight and molecular weight distribution by GPC of the THF soluble component of the binder resin were stabilized in a 40 ° C. heat chamber measured by the following method, and 1 ml of THF as a solvent was added to the column at this temperature per minute. Flow at a flow rate and measure by injecting about 100 μl of THF sample solution. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the number of counts. As a standard sample for preparing a calibration curve, for example, a standard polystyrene sample having a molecular weight of about 10 ² to 10 ⁷ manufactured by Tosoh Corporation or Showa Denko KK is suitably used. . An RI (refractive index) detector is used as the detector. As the column, it is preferable to combine a plurality of commercially available polystyrene gel columns. For example, a combination of shodex GPC KF-801, 802, 803, 804, 805, 806, 807, 800P manufactured by Showa Denko, TSKge1G1000H (HXL), G2000H (HXL), G3000H (HXL), G4000H (HXL), G5000H (HXL), G6000H (HXL), G7000H (HXL) The combination of TSKguardcolumn is mentioned.

  In particular, the column structure is preferably a combination of A-801, 802, 803, 804, 805, 806 and 807 manufactured by Showa Denko KK.

  Next, when the THF-insoluble content is 0 to 10% by mass, good low-temperature fixability is achieved by fixing the high-speed machine with a polymer insoluble in a good solvent below a certain threshold value. .

  If the insoluble content of the color toner by Soxhlet extraction with tetrahydrofuran solvent exceeds 10% by mass, problems usually do not occur, but there is not enough heat to print many sheets at a high speed in a low temperature environment. In addition, when using rough paper with a roughened surface, fixing to the paper tends to be insufficient.

  Here, a method for measuring the THF-insoluble matter is shown below.

<Method for separating THF-insoluble matter and THF-soluble matter in resin composition>
The THF-insoluble content refers to the mass ratio of the ultra-high polymer component (substantially crosslinked polymer) that has become insoluble in the THF solvent in the resin composition in the toner particles. The THF-insoluble content is defined as a value measured as follows.

A toner sample of 0.5 to 1.0 g is weighed (w ₁ g), put into a cylindrical filter paper (for example, No. 86R manufactured by Toyo Filter Paper), subjected to a Soxhlet extractor, and extracted for 6 hours using 100 to 200 ml of THF as a solvent. After evaporating the soluble component extracted with the THF solvent, it is vacuum-dried at 100 ° C. for several hours, and the amount of the THF-soluble resin component is weighed (W ₂ g). The mass of components other than the resin component such as pigment and wax in the toner is defined as (W ₃ g). The THF-insoluble content can be obtained from the following formula.

In the present invention, further, 2) the toner has a soluble content of 20 to 50% by mass in a 1: 1 mixed solvent of acetone / isopropyl alcohol, and the weight average molecular weight (Mw2) of the soluble component in the mixed solvent is 2000 to 15000, and it is necessary that Mw1 and Mw2 satisfy the relationship of 2 <Mw1 / Mw2 <15.

  When the soluble content of the toner in a 1: 1 mixed solvent of acetone / isopropyl alcohol is 20 to 50% by mass, a low molecular weight release agent is present due to the moderate presence of a polymer that is soluble in a medium good solvent. It is possible to prevent the component and the high molecular weight resin component from being separated into layers. In terms of development characteristics, it is possible to prevent migration of the low molecular release agent component to the surface layer and to have excellent durability. In terms of fixing characteristics, it is possible to prevent the low-molecular release agent component from being separated too much and impair the function as a release agent, and to obtain excellent high-temperature offset resistance.

  When the toner has a soluble content in an acetone / isopropyl alcohol 1: 1 mixed solvent of less than 20% by mass, a low molecular weight release agent component and a high molecular weight are obtained due to a small amount of the polymer soluble in a medium good solvent. The resin component is easily separated into layers.

  When the toner has a soluble content in a 1: 1 solvent mixture of acetone / isopropyl alcohol exceeding 50% by mass, the low molecular weight release agent component and the high molecular weight resin component can be prevented from separating into layers. High temperature offset resistance and durability stability characteristics are difficult to express. Moreover, since low molecular weight components increase as a whole, transferability tends to deteriorate.

  The toner should have a weight average molecular weight (Mw2) of 2000 to 15000 in a soluble part in a 1: 1 solvent mixture of acetone / isopropyl alcohol.

  When the weight average molecular weight (Mw2) of the soluble component is less than 2000, there are relatively many low molecular components in the surface layer, and in the development characteristics, the migration of the low molecular release agent component to the surface layer can be prevented. Therefore, durability is inferior.

  When the weight average molecular weight (Mw2) of the soluble component exceeds 15000, the characteristics are similar to those of the polymer resin, and therefore the effect of preventing the layer separation of the low molecular weight release agent component and the high molecular weight resin component is reduced. End up.

  In the present invention, in addition, the above-described Mw1 and Mw2 must satisfy the relationship of 2 <Mw1 / Mw2 <15.

  When Mw1 and Mw2 are in the relationship of 2 <Mw1 / Mw2 <15, the high molecular weight resin component and the intermediate molecular weight component are appropriately balanced, so that the characteristic expression of the high molecular weight resin component is sufficiently exhibited. In terms of development characteristics, it is possible to prevent migration of the low molecular release agent component to the surface layer and to have excellent durability. In the fixing characteristics, it is possible to prevent the low-molecular release agent component from being separated too much and impair the function as a release agent, and to obtain excellent high temperature offset resistance.

  When Mw1 and Mw2 are in a relationship of Mw1 / Mw2 <2, it is a case where Mw1 is small and Mw2 is large, and high temperature offset resistance and durability stability characteristics of the high molecular weight resin component are difficult to be exhibited. End up.

  If the relationship between Mw1 and Mw2 is 15 <Mw1 / Mw2, conversely, Mw1 is large and Mw2 is small, and the low-molecular release agent component is too divided to impair the function as a release agent. End up.

  Here, the measuring method of the soluble part with respect to 1: 1 mixed solvent of acetone / isopropyl alcohol is shown below.

  In the present invention, the soluble component in a 1: 1 mixed solvent of acetone / isopropyl alcohol is near the toner surface layer that is soluble in the 1: 1 mixed solvent of acetone / isopropyl alcohol in the resin composition in the toner. Indicates the mass proportion of the medium polymer component present. The soluble content is defined as a value measured as follows.

  A toner sample (1.0 g) is weighed, and 60 ml of a 1: 1 mixed solvent of acetone / isopropyl alcohol is used as a solvent and stirred and extracted at room temperature (20 ° C.) for 12 hours. Soluble components extracted by the mixed solvent are evaporated. After that, it is vacuum dried at 100 ° C. for several hours, and the amount of the mixed solvent soluble resin component is weighed.

  In the present invention, although not essential, it is more preferable that the Mw1 and Mw2 satisfy the relationship 3 <Mw1 / Mw2 <10.

  It is more preferable that the toner has at least two peaks at 1000 to 20000 in the molecular weight distribution of the soluble part in the 1: 1 solvent mixture of acetone / isopropyl alcohol.

  In the present invention, more preferred embodiments will be described below.

In the present invention, the hexane soluble content of the toner is 6 to 15% by mass,
The soluble component is mainly composed of wax,
In the molecular weight distribution of the soluble component, it has at least one peak at 500 to 6000,
The weight average molecular weight (Mw3) is 500 to 5000,
More preferably, the Mw2 and Mw3 satisfy the relationship 1.5 <Mw2 / Mw3 <15.

  It is more preferable to have at least two peaks at 500 to 6000 in the molecular weight distribution of the soluble part of the toner in the hexane solvent because the above-described effect is emphasized.

  Examples of the wax used as the release agent in the present invention include polymethylene wax such as paraffin wax, polyolefin wax, microcrystalline wax, and Fischer tropish wax, amide wax, ketone wax, higher fatty acid, long chain alcohol, and ester wax. And derivatives such as these graft compounds and block compounds.

  Examples of the wax preferably used include linear alkyl alcohols having 15 to 100 carbon atoms, linear fatty acids, linear acid amides, linear esters, and montan derivatives. Those from which impurities such as liquid fatty acids have been previously removed from these waxes are also preferred.

  Further, the wax preferably used is a low molecular weight alkylene polymer obtained by polymerizing alkylene with radical polymerization under high pressure or Ziegler catalyst or other catalyst under low pressure; alkylene obtained by thermally decomposing high molecular weight alkylene polymer Polymer: A low molecular weight alkylene polymer produced as a by-product in the polymerization of alkylene, separated and purified; a hydrocarbon polymer distillation residue obtained from a synthesis gas consisting of carbon monoxide and hydrogen by the age method, or a distillation residue And polymethylene wax obtained by extracting and fractionating specific components from a synthetic hydrocarbon obtained by hydrogenation. These waxes may contain an antioxidant.

The toner of the present invention has a fine powder amount of less than 5.04 μm on a number average basis of 15 to 50% and a BET specific surface area (S) of 1.5 to 3.0 (m). ² / g).

  If the amount of fine powder of less than 5.04 μm on a number average basis is less than 15% by number, the density of toner increases, and toner deterioration and drum fusion occur due to the closest packing of toner in the developing machine and at the cleaning site. It becomes easy. When the amount of fine powder of less than 5.04 μm on the number average basis is 50% by number or more, the toner is likely to be scattered and the background fog is likely to occur or the member is likely to be contaminated.

  In the present invention, the average particle diameter of the toner was measured using a Coulter counter. That is, a Coulter Counter TA-II type or Coulter Multisizer (manufactured by Coulter, Inc.) is used as a measuring device. As the electrolyte, first grade sodium chloride is used to prepare an approximately 1% NaCl aqueous solution. For example, ISOTON-II (manufactured by Coulter) can be used. As a measuring method, 0.1 to 5 ml of a surfactant, preferably alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the volume and number of toners are measured by using the measuring apparatus with a 100 μm aperture as the aperture. Distribution was calculated. Then, a ratio of less than 5.04 μm obtained from the number distribution related to the present invention was obtained.

  As channels, 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to less than 6.35 μm; 6 Less than 35 to 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; Use 13 channels less than 40 μm; 25.40 to less than 32.00 μm; 32.00 to less than 40.30 μm.

When the specific surface area of the toner by nitrogen adsorption by the BET method is less than 1.5 m ² / g, the absolute amount of the inorganic fine powder is small and the image uniformity is not satisfied or the toner is likely to deteriorate.

When the specific surface area of the toner by nitrogen adsorption by the BET method is larger than 4.0 m ² / g, the absolute amount of the inorganic fine powder is large, the free inorganic fine powder contaminates the member, or the surface friction coefficient μ decreases. Horizontal streaks are likely to occur.

In the present invention, the measurement of the BET specific surface area of the powder is performed as follows using a specific surface area meter autosorb 1 manufactured by QUANTACHROME. About 0.1 g of a measurement sample is weighed in a cell and degassed for 12 hours or more at a temperature of 40 ° C. and a degree of vacuum of 1.0 × 10 ⁻³ mmHg. Thereafter, nitrogen gas is adsorbed while being cooled with liquid nitrogen, and a value is obtained by a multipoint method.

  The average circularity of the toner of the present invention is preferably 0.960 to 1.000.

  Here, the flow type particle image measuring apparatus is an apparatus that statistically performs image analysis of particle imaging, and the average circularity is calculated by the arithmetic average of the circularity obtained by the following equation using the apparatus.

  In the above equation, the perimeter of the particle projection image is the length of the contour line obtained by connecting the edge points of the binarized particle image, and the perimeter of the equivalent circle is the binarized particle This is the length of the outer circumference of a circle having the same area as the image. The equivalent circle diameter is the diameter of a circle having the same area as the area of the measured two-dimensional image of the particles.

  FPIA-1000 (manufactured by Toa Medical Electronics Co., Ltd.) is used as a flow type particle image measuring device. As a measurement method, 0.02 g of a measurement sample is added to 10 ml (20 ° C.) of a solution prepared by adding 0.1 to 0.5 mass% of a surfactant (preferably Wako Pure Chemicals Contaminone) to ion-exchanged water. To prepare a sample dispersion. As a means for dispersion, an ultrasonic disperser UM-50 manufactured by SMT Co., Ltd. (vibrator is a titanium alloy tip of 5φ) is used, and the dispersion time is set to 5 minutes, and the temperature of the dispersion medium does not exceed 40 ° C. Cooled to. In the measurement, the range of 0.60 to 400 μm is divided into 226 channels, and in the actual measurement, particles are measured in a range where the equivalent circle diameter is 0.60 μm or more and less than 159.21 μm.

  When the average circularity is 0.960 to 1.000, the toner shape is almost spherical, so that there is little transfer residue, and a good result is obtained with less load in charging in the roller and recovery in the cleaning unit. When the average circularity is less than 0.960, a large amount of toner remains after transfer, and charging roller contamination and fusing in the cleaning portion are likely to occur.

  The melt index value (MI) at 135 ° C. of the toner of the present invention is preferably 10 to 60.

  This is because it is difficult to judge the behavior of the toner, which is a composite of various functional substances, based only on the physical properties and addition amount of the material substance, and the gel content (insoluble content) and non-gel content of the binder resin ( It is considered that it can be evaluated as a complex of a release agent) and a release agent.

  In the present invention, by setting the toner melt index (temperature 135 ° C., load 1.2 kg) in 10 minutes to 10 to 60 g, color reproducibility and fixability without impairing durability stability in development. Stable full-color images can be obtained. When the melt index of the toner is less than 10, color mixing is insufficient and color reproducibility is poor. When the melt index of the toner exceeds 60, the durability stability during development deteriorates, and the fixability tends to be inferior to the high temperature offset resistance.

  Here, a method for measuring the melt index of the toner will be described below.

<Measurement of melt index>
The melt index indicates a discharge amount in 10 minutes at an arbitrary temperature and load. In this invention, it is set as the value measured on condition of the following. This basically complies with <JIS standard K-7210>.

  Semi-automatic 2-A Melt Index (Toyo Seiki Co. Ltd) is used as a measuring device.

  An orifice having a hollow inner diameter of 2.095 mm is put, and the temperature is previously adjusted to 135 ° C., and 3 to 8 g of a toner sample is weighed and put therein. At this time, set the metal piston while being careful not to enter air bubbles, and keep the temperature for 5 minutes or more. Thereafter, measurement is performed while applying a constant load such that the sum of the piston and the weight is 1.2 kg. The measurement may be performed at an arbitrary time and converted to a discharge amount of 10 minutes.

  The method for producing the toner of the present invention is a method in which a toner is directly produced using a suspension polymerization method; toner particles are produced by direct polymerization in the presence of a water-soluble polymerization initiator that is soluble in a monomer. Examples thereof include production of toner particles by an emulsion polymerization method typified by a soap-free polymerization method. In addition, production of an interfacial polymerization method such as a microcapsule production method, an in situ polymerization method, a coacervation method, and the like can also be mentioned. Furthermore, an interfacial association method for aggregating at least one kind of fine particles to obtain a desired toner may be used. Alternatively, a method in which the toner obtained by the pulverization method is spheroidized by a mechanical impact force can be used.

  Among these, a suspension polymerization method that can easily obtain toner particles having a small particle diameter is particularly preferable. When suspension polymerization is used as a method for producing toner particles, the toner particles can be produced directly by the following production method.

  Adds a colorant, polymerization initiator, cross-linking agent, and other additives to the monomer, and contains a dispersion stabilizer that is uniformly dissolved or dispersed by a homogenizer, ultrasonic disperser, etc. Disperse in an aqueous medium with a normal stirrer, homomixer or homogenizer. Preferably, granulation is performed by adjusting the stirring speed and time so that the droplets of the monomer composition have a desired toner particle size. Thereafter, stirring may be carried out to such an extent that the particle state is maintained and the sedimentation of the particles is prevented by the action of the dispersion stabilizer. Polymerization is carried out at a polymerization temperature of 40 ° C. or higher, usually 50 to 80 ° C. (preferably 55 to 70 ° C.). The temperature may be raised in the latter half of the polymerization reaction, and the pH may be changed as necessary. In the present invention, in order to remove unreacted polymerizable monomers and by-products that cause odor during toner fixing, the aqueous medium is partially distilled off in the latter half of the reaction or after the completion of the reaction. May be. After completion of the reaction, the produced toner particles are collected by washing and filtration and dried.

  The following describes the material of the polymerization toner.

  As the polymerizable monomer used when the toner of the present invention is produced by the polymerization method, a vinyl polymerizable monomer capable of radical polymerization is used. As the vinyl polymerizable monomer, a monofunctional polymerizable monomer is mainly used. Monofunctional polymerizable monomers include styrene; α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, pn-butyl. Styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p -Styrene derivatives such as phenylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, n-amyl acrylate, n-hexyl acrylate, 2 -Ethylhexyl acrylate acrylic polymerizable monomers such as n-octyl acrylate, n-nonyl acrylate, cyclohexyl acrylate, benzyl acrylate, dimethyl phosphate ethyl acrylate, diethyl phosphate ethyl acrylate, dibutyl phosphate ethyl acrylate, 2-benzoyloxyethyl acrylate; Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, iso-propyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, tert-butyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate , N-nonyl methacrylate, diethyl phosphate ethyl methacrylate Methacrylic polymerizable monomers such as dibutyl phosphate ethyl methacrylate; methylene aliphatic monocarboxylic acid esters; vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate, vinyl formate; vinyl methyl ether Vinyl ether such as vinyl ethyl ether and vinyl isobutyl ether; vinyl ketone such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropyl ketone.

  In the present invention, the above monofunctional polymerizable monomers are used alone or in combination of two or more.

  In the present invention, a water-soluble initiator may be used in combination as an aid to the reaction. Examples include ammonium persulfate, potassium persulfate, 2,2′-azobis (N, N′-dimethyleneisobutyroamidine) hydrochloride, 2,2′-azobis (2-aminodinopropane) hydrochloride, azobis (isobutyl) Amidine) hydrochloride, sodium 2,2′-azobisisobutyronitrile sulfonate, ferrous sulfate or hydrogen peroxide.

  In order to control the degree of polymerization of the polymerizable monomer, a chain transfer agent, a polymerization inhibitor or the like can be further added and used.

  Dispersion stabilizers include tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, and barium sulfate. , Bentonite, silica, alumina, hydroxyapatite and the like. Usually, it is preferable to use 300 to 3000 parts by weight of water as a dispersion medium with respect to 100 parts by weight of the monomer composition.

  As the organic compound, for example, polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose, ethylcellulose, sodium salt of carboxymethylcellulose, starch and the like are used. These dispersants are preferably used in an amount of 0.2 to 2.0 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

  Other dispersion stabilizers preferably used include sparingly water-soluble metal salts of sulfuric acid, carbonic acid, phosphoric acid, pyrophosphoric acid, and polyphosphoric acid. These are acid alkali metal salts and metal halide salts under high-speed stirring in a dispersion medium. It is preferable to prepare by this reaction.

  In order to refine these dispersants, 0.001 to 0.1% by mass of a surfactant may be used in combination. Specifically, commercially available nonionic, anionic and cationic surfactants can be used. For example, sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, calcium oleate and the like are preferably used.

  In the present invention, when a condensation compound is used, for example, polyester, polycarbonate, phenol resin, epoxy resin, polyamide, cellulose and the like can be mentioned. More preferably, polyester is desired due to the variety of materials.

  The colorant used in the present invention is carbon black or a known yellow / magenta / cyan colorant as shown below.

  As the yellow colorant, compounds typified by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds are used. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 168, 180, etc. are preferably used.

  As the magenta colorant, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds are used. Specifically, C.I. I. Pigment Red 2, 3, 5, 6, 7, 23, 48; 2, 48; 3, 48; 4, 57; 1, 81; 1, 122, 146, 166, 150, 169, 177, 184, 185, 202, 206, 220, 221, 254 are particularly preferred.

  As the cyan colorant used in the present invention, copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds, and the like can be used. Specifically, C.I. I. Pigment Blue 1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, 66 and the like are particularly preferably used. These colorants can be used alone or in combination and further in the form of a solid solution. The colorant of the present invention is selected from the viewpoints of hue angle, saturation, brightness, weather resistance, OHP transparency, and dispersibility in the toner. The colorant is added in an amount of 1 to 20 parts by mass with respect to 100 parts by mass of the resin.

  As the toner additive that can be used in the present invention, oil-treated inorganic fine particles such as silica and titania are preferably used. In addition to oxides such as zirconium oxide and magnesium oxide, silicon carbide, silicon nitride, boron nitride, aluminum nitride, magnesium carbonate, organosilicon compounds, and the like can be used in combination.

Silica is preferable in that the coalescence of the primary particles can be controlled arbitrarily to some extent depending on the starting material or the oxidation conditions such as temperature. For example, the silica can be either a so-called dry method produced by vapor phase oxidation of silicon halide or alkoxide, or a so-called wet silica produced from alkoxide, water glass, etc. However, dry silica is preferable because it has few silanol groups on the surface and inside of the silica fine powder and few production residues such as Na ₂ O and SO ₃ ²⁻ . In dry silica, it is also possible to obtain composite fine powders of silica and other metal oxides by using other metal halogen compounds such as aluminum chloride and titanium chloride together with silicon halogen compounds in the production process. Is also included.

  Furthermore, the silica is preferably hydrophobized in order to reduce the dependency of the toner charge amount on the environment, such as temperature and humidity, and to prevent excessive release from the toner surface. Examples of the hydrophobizing agent include coupling agents such as a silane coupling agent, a titanium coupling agent, and an aluminum coupling agent. In particular, the silane coupling agent reacts with residual groups on the inorganic oxide fine particles or adsorbed water to achieve a uniform treatment, which is preferable in terms of stabilizing charging of the toner and imparting fluidity.

The silane coupling agent has the following general formula Rm SiYn
R: an alkoxy group m: an integer of 1 to 3 Y: an alkyl group, a hydrocarbon group including a vinyl group, a glycidoxy group, and a methacryl group n: an integer of 1 to 3, for example, vinyltrimethoxysilane, vinyl Triethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, methyltrimethoxysilane, methyltriethoxysilane, isobutyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, hydroxypropyltrimethoxy Examples include silane, phenyltrimethoxysilane, n-hexadecyltrimethoxysilane, and n-octadecyltrimethoxysilane.
More preferably, C _a H _{2a + 1} —Si (OC _b H _{2b + 1} ) ₃
a = 4-12, b = 1-3.

  Here, when a in the general formula is smaller than 4, the treatment becomes easy, but the hydrophobicity cannot be sufficiently achieved. On the other hand, if a is greater than 12, the hydrophobicity is sufficient, but the coalescence between the particles increases, and the fluidity imparting ability decreases.

  When b is larger than 3, the reactivity is lowered and the hydrophobicity is not sufficiently performed. Therefore, a in the above general formula is 4 to 12, preferably 4 to 8, and b is 1 to 3, preferably 1 to 2.

  With respect to the oil treatment of silica, untreated silica may be directly treated with oil, but it is more preferable from the viewpoint of charging stability that the hydrophobized silica is further treated with oil. As the oil, dimethylpolysiloxane, methylhydrogenpolysiloxane, paraffin, mineral oil and the like can be used, and among them, dimethylpolysiloxane excellent in environmental stability is preferable. The appropriate amount of oil used for the treatment is 2 to 40 parts by mass with respect to 100 parts by mass of the silica fine particle matrix.

  In the toner of the present invention, other additives such as a lubricant powder such as polyethylene fluoride powder, zinc stearate powder, polyvinylidene fluoride powder, cerium oxide powder, silicon carbide powder and the like within a range that does not substantially adversely affect the toner. An abrasive such as strontium titanate powder, an anti-caking agent such as aluminum oxide powder, or a conductivity imparting agent such as carbon black powder, zinc oxide powder or tin oxide powder, and organic and inorganic fine particles of reverse polarity. A small amount can be used as a developability improver.

  Next, an image forming method of the present invention, an image forming apparatus that implements the method, and a process cartridge will be described.

  In the present invention, when the MD-1 hardness of the developing roller (see FIGS. 1 and 2) which is a toner carrier is 20 to 40, it interacts with the essential conditions relating to the toner and provides a more excellent image forming method. I can do it. Details are described below.

  First, in order for the toner to be sufficiently charged so as not to cause defects such as fogging, the MD-1 hardness is preferably 20 or more. On the other hand, when the hardness of the developing roller is high, the MD-1 hardness is preferably set to 40 or less because it is easy to charge up under low humidity in a high-speed process.

  When the MD-1 hardness is less than 20, there is a problem of deformation of the roller itself during long-term storage, and there is a tendency that charging of the toner is insufficient, which is not preferable, such as fogging and an increase in consumption. .

  On the other hand, when the MD-1 hardness exceeds 40, when the toner contains both a resin having a sulfur atom and a metal compound of an aromatic oxycarboxylic acid, the toner itself has a high ability to charge and low humidity in a high-speed process. Since it becomes easy to charge up below, it is not preferable.

  The MD-1 hardness of the roller provided with the surface layer is 5 in an environment of normal temperature and normal humidity (23 ° C., 55% RH) using a micro rubber hardness meter MD-1 type, Type A (manufactured by Kobunshi Keiki Co., Ltd.). For a roller that has been left for more than an hour, the vicinity of the central portion of the roller was measured over five points, and the average value was obtained.

  An image forming method to which the present invention can be applied will be described below with reference to the accompanying drawings.

(Non-magnetic one-component image forming device)
(1) Example of Image Forming Apparatus FIG. 3 is a schematic configuration diagram of an example of an image forming apparatus according to the present invention. The image forming apparatus of this example is a tandem type electrophotographic color (multicolor image) printer of a tandem type in which a plurality of image bearing members (latent image carriers) as photosensitive drums are arranged one above the other.

  PY, PM, PC, and PBk are first to fourth image forming units (image forming units) for forming toner images of yellow (Y), magenta (M), cyan (C), and black (Bk), respectively. Unit), which are arranged in the image forming apparatus main body in parallel from the bottom to the top.

  These first to fourth image forming units PY, PM, PC, and PBk have the same configuration and electrophotographic image forming function except that the colors of the toner images formed are different as described above. Yes. That is, each of the first to fourth image forming units includes a drum-type electrophotographic photosensitive member (photosensitive drum) 1 as a first image carrier, a charging roller 2 as a primary charging unit, and a laser as an exposure unit. The irradiation device 3 includes a toner developing device 4 as a developing unit, a primary transfer roller 5 as a primary transfer unit, a blade cleaning device 6 as a cleaning unit, and the like. The developers accommodated in the toner developing devices 4 of the first to fourth image forming units are yellow toner, cyan toner, magenta toner, and black toner, respectively. Each color toner will be described later.

  The image forming apparatus according to the present exemplary embodiment includes four processes of the photosensitive drum 1, the charging roller 2, the developing device 4, and the blade cleaning device 6 in the first to fourth image forming units PY, PM, PC, and PBk, respectively. The apparatus is a process unit (process cartridge) that is detachable and replaceable with respect to the main body of the image forming apparatus.

  Reference numeral 30 denotes an endless belt-shaped intermediate transfer belt as a second image carrier, and the photosensitive drum 1 side (front side of the printer) of the first to fourth image forming portions PY, PM, PC, and PBk. In FIG. 3, the four image forming units are arranged in the vertical direction by being suspended between a plurality of support rollers (not shown). In each of the first to fourth image forming units, the primary transfer roller 5 is in pressure contact with the photosensitive drum 1 via the intermediate transfer belt 30. A contact portion between each photosensitive drum 1 and the intermediate transfer belt 30 is a primary transfer portion.

  In each of the first to fourth image forming units PY, PM, PC, and PBk, each photosensitive drum 1 that is driven to rotate forward is rotated by a charging roller 2 to which a charging bias is applied from a power supply circuit (not shown). Primary charging processing is uniformly performed to a predetermined polarity and potential, and the charging processing surface is subjected to each of the image patterns of yellow, magenta, cyan, and black, which are color separation component images of full-color images, by the LED array device 3. The optical image exposures LY, LM, LC, and LBk are performed, and an electrostatic latent image of image information is formed on each photosensitive drum 1. Each of the electrostatic latent images is developed as a toner image by the developing device 4 so that each of the first to fourth image forming portions PY, PM, PC, and PBk has an electrophotographic process on the surface of each photosensitive drum 1. As a result, yellow, magenta, cyan, and black color toner images, which are color separation component images of the full-color image, are formed at a predetermined sequence control timing.

  Then, in each of the first to fourth image forming units PY, PM, PC, and PBk, the yellow, magenta, cyan, and black color toner images formed on the surface of each photosensitive drum 1 are the positive images of each photosensitive drum 1. The first to fourth image forming units PY, PM, PC, and PBk with respect to the surface of the intermediate transfer belt 30 that is driven to rotate at the same speed as the photosensitive drum 1 in the clockwise direction of the forward arrow in the rotation direction. In the primary transfer portion, the images are sequentially superimposed and transferred to the primary transfer roller by a primary transfer bias applied from a power supply circuit (not shown). As a result, an unfixed full-color toner image (mirror image) is synthesized and formed on the surface of the intermediate transfer belt 30 that is rotationally driven.

  In each of the first to fourth image forming units PY, PM, PC, and PBk, the transfer residual toner remaining on each photosensitive drum 1 after the primary transfer of the toner image to the intermediate transfer belt 30 is performed by the cleaning blade of the blade cleaning device 6. It is removed and stored in the storage unit 6b in the device 6.

  32 is a secondary transfer roller, and 32a is a counter roller. The counter roller 32a is disposed inside the intermediate transfer belt at the lower end side of the intermediate transfer belt 30, and the secondary transfer roller 32 sandwiches the intermediate transfer belt 30 between the counter roller 32a and the intermediate transfer belt 30. Is disposed in contact with the outer surface. A contact portion between the secondary transfer roller 32 and the intermediate transfer belt 30 is a secondary transfer portion.

  Reference numeral 40 denotes a paper feed cassette disposed in the lower part of the main body of the image forming apparatus, in which a transfer material P as a final recording medium is stacked and accommodated. The CPU 80 drives the conveying means (pickup roller) 31 at a predetermined sequence control timing to separate and feed one transfer material P in the paper feed cassette 40, and feeds it to the secondary transfer section at a predetermined timing. . The unfixed full-color toner image synthesized and formed on the intermediate transfer belt 30 is transferred onto the surface of the transfer material P by a secondary transfer bias applied from a power supply circuit (not shown) to the secondary transfer roller 32 in the secondary transfer portion. It will be batch-transcribed.

  The transfer material P that has passed through the secondary transfer portion is separated from the surface of the intermediate transfer belt 30 and sent to the fixing device 7 by the transport belt 35.

  The transfer residual toner remaining on the intermediate transfer belt 30 is removed by the cleaning blade of the blade cleaning device 33 and sent to the waste toner box 34 to be stored.

  The unfixed full-color toner image on the transfer material P sent to the fixing device 7 is melted and fixed to the transfer material P by applying heat and pressure by the fixing device 7, passes through the sheet path 41, and the upper surface of the image forming apparatus main body. The sheet is discharged as a color image formed product onto a paper discharge tray 36 disposed in the above.

  The present invention will be specifically described below with reference to examples and comparative examples.

(Black toner production example 1)
3 parts by mass of tricalcium phosphate is added to 900 parts by mass of ion-exchanged water heated to 65 ° C., and stirred at 10,000 rpm using a TK homomixer (made by Tokushu Kika Kogyo Co., Ltd.) to obtain an aqueous medium. It was.

on the other hand,
Styrene 75 parts by mass 2-ethylhexyl acrylate 25 parts by mass divinylbenzene 0.01 parts by mass saturated polyester resin (1) 2 parts by mass (polycondensate of propylene oxide-modified bisphenol A and isophthalic acid,
(Tg = 65 ° C., Mn = 17000, Mw / Mn = 2.4)
Saturated polyester resin (2) 2 parts by mass (polycondensate of propylene oxide modified bisphenol A and terephthalic acid,
Tg = 55 ° C., Mn = 2500, Mw / Mn = 1.9)
Carbon black (trade name: MA-100, manufactured by Mitsubishi Chemical Co., Ltd.) 10 parts by mass Methylcalixarene (produced by Orient Chemical Co., Ltd.) 2 parts by mass Disperse the above formulation uniformly using an attritor (Mitsui Miike Chemical Co., Ltd.) Mixed. This monomer composition is heated to 65 ° C.
Paraffin wax (maximum endothermic peak in DSC measurement at 77 ° C.), Mn = 900, Mw / Mn = 1.5) 10 parts by mass was added, mixed and dissolved, and 5 mass parts of a polymerization initiator (t-butylperoxypivalate). Part was dissolved.

The polymerizable monomer system was put into the aqueous medium, and the mixture was granulated by stirring at 10,000 rpm for 7 minutes with a TK homomixer in an N ₂ atmosphere at 70 ° C. As a first reaction, the mixture was then reacted at 70 ° C. for 4 hours while stirring with a paddle stirring blade.

Thereafter, 10 parts by mass of styrene is gradually added again over 30 minutes, and then 1.0 part by mass of a polymerization initiator (t-butylperoxypivalate) is gradually dissolved in xylene solution over 30 minutes. It was dripped. Further, 0.2 parts by mass of isopropanol was added dropwise as a chain transfer agent. As a second reaction, the reaction was carried out at 70 ° C. for 4 hours. Finally, the liquid temperature was raised to 85 ° C. and stirring was continued for 3 hours.

  Hydrochloric acid was added to the suspension cooled to room temperature (25 ° C.) to dissolve the calcium phosphate salt, followed by filtration and washing with water to obtain wet colored particles.

  Next, the particles were dried at 40 ° C. for 12 hours to obtain black colored particles (toner particles) having a weight average particle diameter of 6.9 μm.

100 parts by weight of the toner particles and 0.7 parts by weight of hydrophobic silica fine powder having a BET value of 300 m ² / g treated with silicone oil are mixed with a Henschel mixer (Mitsui Miike Chemical Co., Ltd.) to obtain a black toner. 1 was obtained. Table 1 shows the physical properties of Black Toner 1.

(Black toner production example 2)
The same method as in Toner Production Example 1 except that the addition amount of the polymerization initiator in the first reaction is changed to 8 parts by mass and the chain transfer agent in the second reaction is changed to 0.3 parts by mass. A black toner 2 was obtained. Table 1 shows the physical properties of Black Toner 2.

(Black toner production example 3)
A black toner 3 was obtained in the same manner as in Toner Production Example 1 except that the amount of the polymerization initiator added in the first reaction was changed to 3 parts by mass. Table 1 shows the physical properties of the black toner 3.

(Black toner production examples 4 and 5)
Black toners 4 and 5 were obtained in the same manner as in Toner Production Example 1 except that the amount of paraffin wax added was changed. Table 1 shows the physical properties of the black toner.

(Black toner production examples 6 and 7)
Black toners 6 and 7 were obtained in the same manner as in Toner Production Example 1 except that the molecular weight of the added paraffin wax was changed. Table 1 shows the physical properties of the black toner.

(Black toner production examples 8 and 9)
Black toners 8 and 9 were obtained in the same manner as in Toner Production Example 1 except that the amount of added tricalcium phosphate was changed. Table 1 shows the physical properties of the black toner.

(Black toner production examples 10 and 11)
Black toners 10 and 11 were obtained in the same manner as in Toner Production Example 1 except that the amount of the hydrophobic silica fine powder to be processed into the toner particles was changed. Table 1 shows the physical properties of the black toner.

(Black toner production examples 12 and 13)
Black toners 12 to 13 were obtained in the same manner as in Toner Production Example 1 except that the amount of divinylbenzene added in the first reaction was changed and the toner production conditions (temperature) were changed. Table 1 shows the physical properties of the black toner.

(Black toner production example 14)
Styrene, 2-ethylhexyl acrylate, divinylbenzene copolymer (Tg = 60 ° C., Mn = 10000, Mw / Mn = 3.0) 100 parts by mass saturated polyester resin (1) 2 parts by mass (propylene oxide modified bisphenol A and isophthal Polycondensates with acids,
(Tg = 65 ° C., Mn = 17000, Mw / Mn = 2.4)
Saturated polyester resin (2) 2 parts by mass (polycondensate of propylene oxide modified bisphenol A and terephthalic acid,
Tg = 55 ° C., Mn = 2500, Mw / Mn = 1.9)
Carbon black (trade name: MA-100, manufactured by Mitsubishi Chemical Corporation) 10 parts by mass Methyl calixarene (manufactured by Orient Chemical Co., Ltd.) 2 parts by mass The above formulation is kneaded, pulverized, and classified to give a weight average particle diameter of 6.9 μm. Black colored particles (toner particles) were obtained.

  Thereafter, a black toner 14 was obtained in the same manner as in Toner Production Example 1. Table 1 shows the physical properties of the black toner.

(Black toner production example 15)
A black toner 15 was obtained in the same manner as in Toner Production Example 1 except that the amount of divinylbenzene added in the first reaction was changed to 0.2 parts by mass. Table 2 shows the physical properties of the black toner 15.

(Black toner production example 16)
Black toner 16 was obtained in the same manner as in Toner Production Example 1 except that the amount of the polymerization initiator added in the first reaction was changed to 12 parts by mass and the reaction temperature was 85 ° C. Table 2 shows the physical properties of the black toner 16.

(Black toner production example 17)
In addition to the saturated polyester resins (1) and (2), the unsaturated polyester resin (3) (polycondensate of propylene oxide-modified bisphenol A and maleic acid, Tg = 60 ° C., Mn = 16000, Mw / Mn = 2. A black toner 17 was obtained in the same manner as in Toner Production Example 1 except that 1.0 part by mass of 2) was added and the chain transfer agent in the second reaction was changed to 3.0 parts by mass. Table 2 shows the physical properties of the black toner 17.

(Black toner production example 18)
Similar to Toner Production Example 1, except that the saturated polyester resin (2) of the first reaction was not added, the saturated polyester resin (1) was changed to 10 parts by mass, and the second reaction was not performed. Thus, black toner 18 was obtained. Table 2 shows the physical properties of the black toner 18.

(Black toner production example 19)
Other than not adding the saturated polyester resin (1) of the first reaction, changing the saturated polyester resin (2) to 10 parts by mass, and changing the polymerization initiator of the second reaction to 2.0 parts by mass A black toner 19 was obtained in the same manner as in Toner Production Example 1. Table 2 shows the physical properties of the black toner 19.

(Black toner production examples 20 and 21)
Toner production other than changing the addition amount of the polymerization initiator in the first reaction, changing the addition amount of the chain transfer agent in the second reaction, and changing the toner production conditions (temperature) Black toners 20 and 21 were obtained in the same manner as in Example 1. Table 2 shows the physical properties of the black toners 20 and 21.

<Examples 1 to 14 and Comparative Examples 1 to 7>
(Image evaluation)
Image evaluation was performed according to the following method using the obtained toners 1 to 21.

  As an image forming apparatus, a remodeling machine in which the process speed of a commercially available laser printer HP CLJ-3700 (manufactured by HP) is changed to 150 mm / second is used, in a low temperature and low humidity environment (15 ° C., 10% RH) It was carried out in a wet environment (30 ° C., 80% RH).

  The fixing device is a commercially available fixing device for a laser printer CLJ-1500 (manufactured by HP) so that the temperature control and the pressing force can be changed, and the fixing device is modified and installed so as to enter CLJ-3700.

  The same cartridge for CLJ-3700 was used with the following changes.

(Manufacturing method of developing roller D-1)
As the shaft core, a SUS cylinder was plated with nickel, and a silane coupling primer was applied and baked.

  Next, the shaft core was placed in a mold, the mold was heated at 100 ° C. for 5 minutes, and conductive dimethyl silicone rubber (Asker C hardness 20 ° product) was injected into the cavity formed in the mold. Subsequently, the silicone rubber was vulcanized and cured by heating at 100 ° C. for 15 minutes, and after cooling, it was demolded to provide an elastic layer on the outer periphery of the shaft core body.

  Next, a necessary amount of TMP-modified TDI is added as a cross-linking material based on a chain-extended polyol, and the solid content of the urethane resin (total amount of the chain-extended polyol and isocyanate used as the cross-linking material) is 18. A mixed solution containing methyl ethyl ketone as a main solvent, adjusted to be mass%, and carbon black (trade name: MA-100, manufactured by Mitsubishi Chemical Co., Ltd.) added to the resin component by 30 parts by mass and sufficiently stirred are dip. Liquid. After immersing and coating the shaft core body 21 provided with the elastic layer 22 in this liquid, the surface layer 23 is provided on the outer periphery of the elastic layer 22 by lifting and drying, and heat-treating at 120 ° C. for 5 hours. A developing roller D-1 was obtained.

As a transfer material, LETTER size XEROX 4024 paper (manufactured by XEROX, 75 g / m ² ) was used.

  Using an image with a printing ratio of 2% in each of a low-temperature and low-humidity environment and a high-temperature and high-humidity environment, 10,000 sheets were printed by the continuous printing method shown below in the single color mode.

  The image forming speed was set to the speed in the plain paper mode.

  Image evaluation was performed based on the following evaluation criteria using the 100th, 5000th, and 10000th images.

  Each evaluation result is shown in Table 3.

[Developability evaluation method]
(Measurement of fogging)
The fog was measured using a REFECTOMETER MODEL TC-6DS (manufactured by Tokyo Denshoku Co., Ltd.) and calculated according to the following formula. A lower fog value is better.
Fog (reflectance;%) = (reflectance of standard paper;%) − (reflectance of white solid portion of sample;%)
A: 1.2% or less B: 1.2% and 2.5% or less C: 2.5% and 4.0% or less D: 4.0% or more

(Transfer efficiency)
For the transfer efficiency, the ratio of the toner basis weight transferred onto the paper with respect to the toner basis weight developed on the photoreceptor under N / N conditions using the image forming apparatus shown in FIG. Evaluation was based on criteria.
A: 90% or more.
B: More than 80% and less than 90%.
C: More than 70% and less than 80%.
D: Less than 70%.

(Solid uniformity)
The obtained solid image on the transfer paper was evaluated as A, B, C, and D with a density difference of 5 points.
A: 2% or less B: Over 2% and 5% or less C: Over 5% and 10% or less D: Over 10%

(Drum fusion)
The drum fusion was evaluated based on the following evaluation criteria by visually observing the drum surface and further observing image defects.
A: Defects are not recognized at all on the drum surface and the image.
B: In the latter half of the durability, the drum surface is slightly stained but does not appear in the image.
C: In the latter half of the durability, some dirt is observed on the drum surface, and some unevenness occurs in the image.
D: In the latter half of the endurance, the drum surface is very dirty, and the image is uneven.

(Stable coating amount on developing roller)
The coating amount stability was evaluated based on the following evaluation criteria for the amount of change in the coating amount on the developing roller after the initial durability of the developer in the developing container and after 10,000 sheets were passed.
A: Change amount is 10% or less.
B: Change amount exceeds 10% and is 15% or less.
C: The amount of change exceeds 15% and is 20% or less.
D: The amount of change exceeds 20%.

[Measurement method for evaluation items]
Using black toner (1), a belt-like image having a toner carrying amount of 0.5 to 0.6 dg / m ² is formed on the leading edge of a recording paper having a basis weight of 75 or 80 g / m ² , and a fixing test is performed. Went. The fixing evaluation results are shown in Table 4.

  The preparation of the unfixed image and the fixability test are performed under normal temperature and normal humidity (23 ° C./60%) unless otherwise specified.

  The configuration of the fixing device is the heating fixing device shown in FIG. 4, and the oil application mechanism is omitted.

  As the pressure roller 30, a roller having a roller hardness of 60 degrees (Asker-C 500 g) obtained by coating a core metal 30 a made of Fe with silicone rubber and PFA resin was used.

As the pressing force, the pressure springs 25a and 25b were adjusted to contact with a surface pressure of 70,000 N / m ² through a paper of 80 g / cm ² to obtain a fixing nip of 6.0 mm.

  Further, the paper was passed under a process speed of 94 mm / sec.

(Fixing start temperature)
The unfixed image created by the above method is fixed by adjusting the temperature of the heating section of the fixing device at a temperature range of 100 to 230 ° C. every 5 ° C., and a load of 4900 N / m ² is applied to the obtained fixed image. The temperature at which the image density reduction rate before and after rubbing is 10% or less is defined as the fixing start temperature. The following four ranks were evaluated according to the degree.
A: The fixing start temperature is less than 140 ° C.
B: The fixing start temperature is 140 ° C. or higher and lower than 150 ° C.
C: The fixing start temperature is 150 ° C. or higher and lower than 160 ° C.
D: The fixing start temperature is 160 ° C. or higher.

(High temperature offset resistance)
The fixing temperature is raised, and the highest temperature at which no offset phenomenon occurs visually is defined as a high temperature offset free temperature, which is used as an index of offset resistance. The following four ranks were evaluated according to the degree.
A: The high temperature offset free temperature is 210 ° C. or higher.
B: High temperature offset free temperature is 200 ° C. or higher and lower than 210 ° C.
C: High temperature offset free temperature is 190 ° C or higher and lower than 200 ° C.
D: High temperature offset free temperature is less than 190 ° C.

(Fixing stability)
The unfixed image created by the above method is continuously fed through 10,000 sheets under the condition of the heating unit set temperature of 170 ° C., and the fixability of the first sheet and the 10,000th sheet is confirmed. The obtained fixed image is rubbed twice with sylbon paper applied with a load of 4900 N / m ² , and fixing is performed when the image density reduction rate before and after the rubbing becomes 10% or less. The following four ranks were evaluated according to the degree.
A: Initially fixed after passing 10,000 sheets and the reduction rate is 10% or less.
B: Fixed initially, but not offset after passing 10,000 sheets, but the density reduction rate is 10% or more.
C: Initially fixed, but offset after 10,000 sheets passed, and the back surface is dirty.
D: Offset is in the initial stage.

(Image gloss (gloss) measurement)
The glossiness measuring instrument used in the present invention was PG-3D (incident angle θ = 75 °) manufactured by Nippon Denshoku Industries Co., Ltd., and the standard surface was black glass with a glossiness of 96.9. As charts, nine unfixed 30 mm × 30 mm patch unfixed images were output on Xerox 4024 paper (75 g paper) or CLC-SK paper (Canon).

(Gloss unevenness in the image: difference in image gloss)
Nine patch images of 30mm x 30mm size are output on Xerox 4024 paper (75g paper, legal size) or CLC-SK A3 size paper (Canon), heating unit set temperature 170 ° C, process speed Paper was passed under the condition of 150 mm / second.

  From the viewpoint of uneven gloss, the difference between the maximum value and the minimum value was evaluated among the gloss values at nine locations in the image when one sheet was passed.

The following four ranks were evaluated according to the degree.
A: The gross difference is less than 5.
B: The gloss difference is 5 or more and less than 10.
C: The gloss difference is 10 or more and less than 15.
D: The gloss difference is 15 or more.

It is explanatory drawing of the developing roller shown as an example of this invention, Comprising: It is the perspective view. It is sectional drawing of the developing roller shown in FIG. It is explanatory drawing of the image forming apparatus using the developing device of this invention. It is explanatory drawing of an example of the fixing device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 .... Photosensitive drum 2 .... Charging roller 3 .... Exposure device 4 .... Developing device 5 .... Primary transfer roller 6 .... Cleaning device 6a ... Cleaning blade 7 .... Fixing device 11 .... Drive motor 12 .... Gear Row 20 ..Development roller 21 ..Shaft core 22 ..Elastic layer 23 ..Surface layer 30 ..Intermediate transfer belt 31 ..Pickup roller 32 ..Secondary transfer roller 33 ..Intermediate transfer belt cleaning device 34. -Waste toner box 35-Paper transport belt 36-Paper discharge section

Claims (11)

A toner obtained by producing a composition containing at least a binder resin, a colorant and a release agent in an aqueous medium,
The binder resin is a styrene polymer, a styrene / acrylate copolymer or a mixture thereof,
The toner has a THF insoluble content of 0 to 10% by mass,
The toner has a THF-soluble component weight average molecular weight (Mw1) of 5,000 to 100,000.
The toner has a soluble component in an acetone / isopropyl alcohol 1: 1 mixed solvent of 20 to 50% by mass, and a weight average molecular weight (Mw2) of the soluble component in the mixed solvent is 2000 to 15000.
The toner wherein Mw1 and Mw2 satisfy a relationship of 2 <Mw1 / Mw2 <15.   The toner according to claim 1, wherein the Mw1 and Mw2 satisfy a relationship of 3 <Mw1 / Mw2 <10. N-hexane soluble content of the toner is 6 to 15% by mass;
The soluble component is mainly composed of wax,
In the molecular weight distribution of the soluble component, it has at least one peak at 500 to 6000,
The weight average molecular weight (Mw3) is 500 to 5000,
The toner according to claim 1, wherein the Mw2 and Mw3 satisfy a relationship of 1.5 <Mw2 / Mw3 <15.   The toner according to any one of claims 1 to 3, wherein the toner has at least two peaks at 1000 to 20000 in the molecular weight distribution of a soluble component in a 1: 1 solvent mixture of acetone / isopropyl alcohol.   The toner according to any one of claims 1 to 4, wherein the toner has at least two peaks at 500 to 6000 in the molecular weight distribution of the n-hexane soluble matter.   The toner is used in an image forming method for forming a toner image on an electrostatic latent image carrier by bringing a toner layer carried on the surface of the toner carrier into contact with the surface of the electrostatic latent image carrier. The toner according to claim 1, wherein the toner is a toner.   7. The toner according to claim 1, wherein the toner has a fine powder amount of less than 5.04 μm on a number average basis of 15% by number or more and less than 60% by number. The toner according to claim 1, wherein the toner has a BET specific surface area (S) of 1.5 to 4.0 (m ² / g).   The toner according to claim 1, wherein the toner has an average circularity of 0.960 to 1.000.   The toner according to claim 1, wherein the toner has a melt index value at 135 ° C. of 10 to 60. In a non-magnetic one-component image forming method for forming a toner image on an electrostatic latent image carrier by bringing a toner layer carried on the surface of the toner carrier into contact with the surface of the electrostatic latent image carrier,
MD-1 hardness of the toner carrier is 20 or more and 40 or less,
The toner is a toner obtained by producing a composition containing at least a binder resin, a colorant and a release agent in an aqueous medium,
The binder resin is a styrene polymer, a styrene / acrylate copolymer or a mixture thereof,
The toner has a THF insoluble content of 0 to 10% by mass,
The toner has a THF-soluble component weight average molecular weight (Mw1) of 5,000 to 100,000.
The toner has a soluble component in an acetone / isopropyl alcohol 1: 1 mixed solvent of 20 to 50% by mass, and a weight average molecular weight (Mw2) of the soluble component in the mixed solvent is 2000 to 15000.
A non-magnetic one-component image forming method, wherein the Mw1 and Mw2 satisfy a relationship of 2 <Mw1 / Mw2 <15.

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