JP6210796B2 - Image forming method - Google Patents

Description

  The present invention relates to an image forming method capable of obtaining a full color image.

  2. Description of the Related Art In recent years, electrophotographic apparatuses such as printer apparatuses have been desired to develop toner that can be easily fixed on a transfer material such as paper at a low temperature from the viewpoint of energy saving. At the same time, as the resolution of the image increases, the glossiness of the image must be controlled and, in the case of a color machine, good color mixing and a wide range of color reproducibility are required in order to approach the image quality of photographs and prints. ing. For example, it is required to obtain an image having a high gloss level close to a photographic quality.

  Therefore, it is necessary to lower the glass transition point (Tg) of the binder resin used for the toner and to lower the average molecular weight of the binder resin used for the toner. However, if the Tg and average molecular weight of the binder resin used for the toner are simply reduced, in the case of a non-magnetic one-component development system that can be developed at a high speed or can be reduced in size, toner fusion or Contamination of parts due to the seepage of wax may occur. In extreme cases, the storage stability of the toner may be impaired and an image may not be obtained.

  That is, if the fixing characteristics are simply improved, the developing characteristics are impaired. Conversely, if priority is given to the development characteristics, there is a case where the fixing characteristics do not increase. In particular, from the viewpoints of high definition and high image quality, the average particle size of toner is in the direction of decreasing the particle size, and it is intended to achieve both low temperature fixability and component contamination due to toner fusion and wax exudation. Making it even more difficult. It is an important issue required for toners to satisfy both seemingly contradictory performances such as development stability and low-temperature fixability of the toners.

  By using low melting point wax, silica fine particles with high fixing rate of silicone oil are used while maintaining low-temperature fixability, and even if left in a high temperature and high humidity environment for a long period of time, it suppresses the exudation of wax in the toner. An example of such a toner has been proposed (see Patent Document 1).

  However, when a toner having silica fine particles having a high immobilization rate of silicone oil is applied to a color machine having an intermediate transfer member, cleaning failure may occur.

  Proposes an example of a toner that combines the opposite effects of image defects such as void and density unevenness while improving the fixing tail by using two types of silica fine particles with different silicone oil fixation rates in the same toner. (See Patent Document 2).

  Certainly, by adding two types of silica fine particles having different functions in the same toner, it is recognized that the latitude spreads against various image problems, and a well-balanced toner design can be performed. However, with respect to the suppression of wax exudation in the toner when left for a long period of time in a high temperature and high humidity environment, the risk of image damage increases depending on the proportion of silica fine particles having a low silicone oil fixation rate. As a result, the use of low melting point waxes is limited, and depending on the transportation process and storage conditions in the warehouse, there are still problems to improve the usability without getting bored.

JP 2009-276643 A JP 2009-276641 A

  The present invention is to solve the above-mentioned problems of the prior art.

An object of the present invention is to provide a full-color image forming method in which an intermediate transfer member is used and toner remaining on the intermediate transfer member is removed using a cleaning blade.
(1) An object of the present invention is to provide an image forming method that is excellent in low-temperature fixability and can satisfy an appropriate glossiness and image density to approximate the image quality of photographs and printing.
(2) An object of the present invention is to provide an image forming method excellent in durability with little member contamination even in image printing after standing for a long period of time in a high temperature and high humidity environment.
(3) It is an object of the present invention to provide an image forming method that is difficult to cause defective cleaning even in full-color image output and has high cleaning properties.

  As a result of intensive studies, the present inventors have found that the above-described problems can be solved by the following configuration, and have reached the present invention.

That is, according to the present invention, (i) a first electrostatic latent image is formed on an electrostatic latent image carrier, and a first selected from the group consisting of cyan toner, magenta toner, yellow toner, and black toner is selected. Developing the first electrostatic latent image with toner to form a first toner image on the electrostatic latent image carrier, and primarily transferring the first toner image to an intermediate transfer member;
(Ii) A second electrostatic latent image is formed on the electrostatic latent image carrier, and a second other than the first toner selected from the group consisting of cyan toner, magenta toner, yellow toner, and black toner. The second electrostatic latent image is developed with the toner to form a second toner image on the electrostatic latent image carrier, and the second toner image is formed on the intermediate transfer member. Primary transfer over the image,
(Iii) forming a third electrostatic latent image on the electrostatic latent image bearing member, and the first toner and the second toner selected from the group consisting of cyan toner, magenta toner, yellow toner, and black toner The third electrostatic latent image is developed with a third toner other than the first toner to form a third toner image on the electrostatic latent image carrier, and the third toner image is formed on the intermediate transfer member. Primary transfer over the first toner image and the second toner image,
(Iv) forming a fourth electrostatic latent image on the electrostatic latent image carrier, the first toner selected from the group consisting of cyan toner, magenta toner, yellow toner, and black toner; The fourth electrostatic latent image is developed with a toner other than the first toner and the fourth toner other than the third toner to form a fourth toner image on the electrostatic latent image carrier, and the fourth toner The image is primarily transferred over the first toner image, the second toner image, and the third toner image on the intermediate transfer member,
(V) Secondary transfer of the first to fourth toner images on the intermediate transfer member onto a transfer material, and heating and fixing the first to fourth toner images on the transfer material. A full-color image forming method in which a full-color image is formed on the transfer material, and residual transfer toner remaining on the intermediate transfer member after secondary transfer is removed using a cleaning blade in contact with the surface of the intermediate transfer member Because
The black toner is 3.0 parts by mass or more and 50.0 parts by mass or less with respect to 100.0 parts by mass of toner particles containing a binder resin, carbon black, and a release agent and untreated silica fine particles. A silica fine particle A having a carbon-based immobilization rate of the silicone oil of 50% or less,
The cyan toner, the magenta toner, and the yellow toner are each composed of toner particles containing a binder resin, a colorant, and a release agent, and 100.0 parts by mass of untreated silica fine particles. Contains silica fine particles treated with 0 to 50.0 parts by mass of silicone oil, and contained in at least one toner selected from the group consisting of the cyan toner, the magenta toner, and the yellow toner The present invention relates to an image forming method in which the silica fine particles contain silica fine particles B having a fixing ratio of 60% or more of the silicone oil based on carbon.

  The image forming method of the present invention is capable of excellent low-temperature fixability even at the time of printing out a large number of sheets in a machine that has been advanced at a high speed and miniaturized. In addition, even when the image is left for a long period of time in a high-temperature and high-humidity environment, the member is less contaminated and has excellent durability. Further, even after full color image output, it is difficult for the intermediate transfer body to be poorly cleaned and the cleaning property is high.

It is a schematic block diagram of an example of the image forming apparatus used for the image forming method of this invention. FIG. 3 is a schematic configuration diagram of an example of an intermediate transfer belt cleaning device used in the image forming method of the present invention. FIG. 3 is a cross-sectional configuration diagram of an example of an intermediate transfer belt used in the image forming method of the present invention. It is a schematic block diagram of an example of a process cartridge used in the image forming method of the present invention. FIG. 5 is a diagram illustrating toner movement of a developing device in the process cartridge of FIG. 4. 2 is a schematic configuration diagram of an example of a fixing device used for the toner of the present invention.

  Hereinafter, the present invention will be described in detail with reference to embodiments of the present invention.

In the image forming method of the present invention, (i) a first electrostatic latent image is formed on the electrostatic latent image carrier, and the first electrostatic latent image is selected from the group consisting of cyan toner, magenta toner, yellow toner, and black toner. The first electrostatic latent image is developed with one toner to form a first toner image on the electrostatic latent image carrier, and the first toner image is primarily transferred to an intermediate transfer member. ii) A second electrostatic latent image is formed on the electrostatic latent image carrier, and a second toner other than the first toner selected from the group consisting of cyan toner, magenta toner, yellow toner, and black toner is used. The second electrostatic latent image is developed with toner to form a second toner image on the electrostatic latent image carrier, and the second toner image is formed on the intermediate transfer member. (Iii) a third electrostatic latent image on the electrostatic latent image carrier. And forming the third electrostatic latent image with a third toner other than the first toner and the second toner selected from the group consisting of cyan toner, magenta toner, yellow toner, and black toner. Development is performed to form a third toner image on the electrostatic latent image carrier, and the third toner image is superimposed on the first toner image and the second toner image on the intermediate transfer member to be primary. (Iv) forming a fourth electrostatic latent image on the electrostatic latent image carrier, the first toner selected from the group consisting of cyan toner, magenta toner, yellow toner, and black toner; The fourth electrostatic latent image is developed with a fourth toner other than the second toner and the third toner to form a fourth toner image on the electrostatic latent image carrier. 4 toner image on the intermediate transfer member Primary transfer is performed on the first toner image, the second toner image, and the third toner image, and (v) the first to fourth toner images on the intermediate transfer member are used as a transfer material. Secondary transfer is performed, and the first to fourth toner images on the transfer material are heated and fixed to form a full color image on the transfer material, which remains on the intermediate transfer body after the secondary transfer. A full-color image forming method for removing untransferred toner using a cleaning blade in contact with the surface of the intermediate transfer member,
The black toner is 3.0 parts by mass or more and 50.0 parts by mass or less with respect to 100.0 parts by mass of toner particles containing a binder resin, carbon black, and a release agent and untreated silica fine particles. A silica fine particle A having a carbon-based immobilization rate of the silicone oil of 50% or less,
The cyan toner, the magenta toner, and the yellow toner are each composed of toner particles containing a binder resin, a colorant, and a release agent, and 100.0 parts by mass of untreated silica fine particles. Contains silica fine particles treated with 0 to 50.0 parts by mass of silicone oil, and contained in at least one toner selected from the group consisting of the cyan toner, the magenta toner, and the yellow toner The silica fine particles are characterized by having silica fine particles B having a fixing rate of 60% or more based on carbon of the silicone oil.

  The low melting point wax used as a release agent is essential for improving the low-temperature fixability. When a toner using a low melting point wax is left in a high temperature and high humidity environment for a long period of time, the wax dispersed in the toner is likely to move and easily ooze out to the toner particle surface. Usually, the wax is present in a crystalline state in the toner. However, if the wax is left for a long period of time under high temperature and high humidity, a part of the wax becomes compatible with the binder resin, so that it is considered that the wax is easy to move. . When the wax oozes out on the surface of the toner particles, members such as a developer carrying member and a developing blade are contaminated, and image defects such as fogging and streaks are likely to occur. In some cases, the fluidity is deteriorated and the uniformity of the solid density is inferior.

  Of silica fine particles treated with 3.0 to 50.0 parts by mass of silicone oil based on 100.0 parts by mass of untreated silica fine particles, the fixing rate of silicone oil is 60% on a carbon basis. When the above silica fine particles are externally added to the toner particles, the seepage of the wax onto the toner surface can be suppressed.

  By increasing the immobilization rate of silicone oil based on carbon content, silicone oil is not released from the silica fine particles and does not migrate to the surface of the toner particles, so that the dispersion state is stably maintained in the toner even if the melting point of the wax is low. be able to. On the other hand, if the carbon oil-based immobilization rate of the silicone oil is low, the silicone oil is released from the silica fine particles and migrates to the toner particle surface, and the same hydrophobic wax is induced and the toner particle surface is easily oozed out. .

  In a full-color image forming method having an intermediate transfer member, removal of transfer residual toner using a cleaning blade is generally performed.

  When the transfer residual toner of the toner to which silica fine particles having an immobilization rate of silicone oil of 60% or more on the basis of carbon are externally added is removed using a cleaning blade, a cleaning failure may occur.

  By increasing the carbon oil-based fixing ratio of the silicone oil in the silica fine particles, the amount of oil interposed between the cleaning blade and the intermediate transfer member is reduced, and the slipperiness is deteriorated. As a result, it seems that this is because the wear of the cleaning blade rubber part is likely to proceed or chipping occurs.

  Therefore, in a full-color image forming method in which the transfer residual toner of the intermediate transfer body is blade-cleaned, at least the black toner contains silica fine particles A having a carbon-based immobilization ratio of 50% or less of silicone oil. Improvements were made.

  When forming full-color images, it is common to use a method (called UCR) that replaces the overlap of yellow, magenta, and cyan with black and reduces the color toner by that amount in order to increase image sharpness and consumption. It has become.

  Therefore, when the black toner contains silica fine particles A having a carbon-based immobilization rate of 50% or less of the silicone oil, the silicone oil is constantly supplied to the cleaning blade portion, thereby suppressing defective cleaning. I can.

  On the other hand, as described above, there is a concern that if the carbon oil-based immobilization rate of the silicone oil is low, the wax tends to exude to the toner particle surface.

  However, when carbon black is used as the colorant for the black toner, it has a high affinity for wax because of its high oil absorption, and can suppress the seepage of wax on the toner particle surface.

  Further, among the cyan toner, magenta toner, and yellow toner, the silica fine particles contained in at least one kind of toner include silica fine particles B having a silicone oil immobilization rate of 60% or more based on carbon. It is.

  By doing so, it is possible to achieve compatibility at a higher level with respect to improving the cleaning property while suppressing the harmful effects caused by the seepage of the wax.

The silicone oil immobilization rate of the silica fine particles A needs to be 50% or less on the basis of the amount of carbon. A more preferable silicone oil immobilization rate is 30% or less based on the amount of carbon.

The silicone oil immobilization rate of the silica fine particles B needs to be 60% or more on the basis of the amount of carbon. Further, the silica oil immobilization rate of the silica fine particles B is preferably 80% or more based on the carbon amount.

  The silicone oil treatment amount of the silica fine particles A and B needs to be 3.0 parts by mass or more and 50.0 parts by mass or less with respect to 100.0 parts by mass of the untreated silica bulk fine particles. When included in this range, the effects of the silica fine particles A and B described above can be sufficiently exhibited. If it is higher than 50.0 parts by mass, it is difficult to uniformly treat the silica fine particles with silicone oil, and the silica fine particles may form aggregates, which is not preferable. Moreover, when it is less than 1.0 part by mass, there is a possibility that the effect expected in this configuration cannot be obtained.

The immobilization rate of silicone oil can be measured by the following quantitative method.
1. Place 0.50 g of silica fine particles and 40 ml of chloroform in a beaker and stir for 2 hours.
2. Stop stirring and let stand for 12 hours.
3. The sample is filtered and washed 3 times with 40 ml of chloroform.

  Next, the amount of carbon is measured.

The sample is burned at 1100 ° C. in an oxygen stream, and the amount of generated CO and CO ₂ is measured by IR absorbance to measure the amount of carbon in the sample. By comparing the amount of carbon before and after extraction of silicone oil, the immobilization rate of silicone oil is calculated.
1. Place 2.00 g of sample in a cylindrical mold and press.
2. 0.15 g of the pressed sample is precisely weighed, placed on a combustion board, and measured with Horiba EMA-110.
3.100− (carbon amount before extraction−carbon amount after extraction) / carbon amount before extraction × 100 is defined as an immobilization rate of silicone oil.

  In the cyan toner, magenta toner, and yellow toner of the present invention, the endothermic amount (J / g) derived from the release agent measured by the first scanning of the differential scanning calorimeter (DSC) is H1 and H2. When the endothermic amount (J / g) obtained by scanning is H2, the silica fine particles A are preferably contained when H1-H2 ≦ 1.45 is satisfied.

  It is possible to achieve a higher level of compatibility with improving the cleaning property while suppressing adverse effects caused by the exudation of the wax.

  A more preferable silicone oil immobilization rate is H1-H2 ≦ 1.00.

  The endothermic amounts H1 and H2 can be measured by the following method using a differential scanning calorimeter (DSC). Set the toner on the DSC. Next, the measurement is performed in the following sequence, and the endothermic peak heat quantity resulting from the release agent in the first cycle is H1, and the endothermic peak heat quantity in the first cycle is H2.

<Sequence>
1st cycle:-Hold at 20 ° C for 1 minute
・ Raise the temperature to 100 ° C. at 10 ° C./min. Hold for 60 minutes after temperature rise
・ Temperature drop to 20 ° C at 1 ° C / min.
Second cycle: · Hold at 20 ° C for 10 minutes
・ Raise the temperature to 100 ° C at 10 ° C / min. Hold for 1 minute after temperature rise
・ Rapid cooling to 20 ℃. Hold for 1 minute after temperature drop

  The DSC measurement is performed as follows. The DSC is measured according to ASTM D3418-82 using, for example, “Q1000” (manufactured by TA Instruments). The temperature correction of the device detection unit uses the melting points of indium and zinc, and the correction of heat uses the heat of fusion of indium. Specifically, about 2 mg of a polar resin / ester wax mixture as a specimen is precisely weighed, placed in an aluminum pan, and measured using the above sequence using an empty aluminum pan as a reference.

  The silica fine particles A and B preferably have a primary particle number average particle diameter (Dn) of 5.0 nm or more and 15.0 nm or less. More preferably, it is 5.0 nm or more and 12.0 nm or less.

  By ensuring the fluidity of the toner, it is possible to obtain a high-quality image with high uniformity of solid density throughout durability. In particular, although details will be described later, in the present invention, when the developer carrying member and the supply member that are preferably used for improving durability are used in an image forming method that rotates in the same direction at the nip portion, fluidity is ensured. But it becomes more important.

  The average primary particle diameter of the silica fine particles A and B is determined by an electron microscope. Specifically, the particle diameter is measured by taking an image of a silica fine particle at a magnification of 200,000 with a transmission electron microscope (TEM) and using the enlarged photograph as a measurement object. Let the average value which measured the particle diameter of arbitrary 200 particle | grains be an average primary particle diameter. In addition, the primary particle diameter in arbitrary silica fine particles makes the maximum distance which can exist in the outline of the silica fine particle the primary particle diameter of the silica fine particle.

  The silica fine particles A are preferably surface-treated with silicone oil after surface treatment with at least one of alkoxysilane and silazane. By treating in this way, the fixing rate of the silicone oil can be lowered and released effectively, and the sliding property between the cleaning blade and the intermediate transfer member is improved. Further, since the surface of the silica fine particles A is hydrophobic even after being released, a highly charged toner can be maintained, and fogging under high temperature and high humidity is difficult to occur.

  The silica fine particle B is preferably surface-treated with at least one of alkoxysilane and silazane after the surface treatment with silicone oil. By treating in this way, it is expected that a stable layer of alkoxysilane or silazane exists on the silicone oil layer. Thereby, the immobilization rate of silicone oil can be increased and release can be suppressed, and a sufficient amount of silicone oil can be uniformly and stably retained on the surface of the silica fine particles. For this reason, the seepage of the wax to the toner particle surface can be suppressed. Further, higher fluidity can be obtained than silica fine particles in which a relatively large amount of silicone oil is present in the outermost layer of silica fine particles. Apart from the viewpoint of the fixing rate, it is possible to suppress the seepage to the toner particle surface than the surface layer of only oil.

  The content of silica fine particles A and silica fine particles B contained in the toner is preferably 0.5% by mass or more and 5.0% by mass or less. When the content of the silica fine particles is within this range, it is easy to maintain good fluidity, cohesiveness, and chargeability of the toner, and it is easy to obtain an image with good image quality. A more preferable range of the content of silica fine particles A and silica fine particles B is 0.6% by mass or more and 3.0% by mass or less.

  The silica fine particles A and B used in the present invention are applicable to both negative toners and positive toners.

  Specific examples of the alkoxysilane and silazane used in the present invention include trimethylethoxysilane, triethylethoxysilane, trimethylpropoxysilane, dimethyldiethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisilazane, hexaethyldisilazane. Hexaphenyldisilazane, diethyltetramethyldisilazane, hexatolyldisilazane, isopropyltrimethoxysilane, and the like. You may use these as 1 type or a mixture of 2 or more types.

  Examples of silicone oils preferably used in the present invention include amino-modified, epoxy-modified, carboxyl-modified, carbinol-modified, methacryl-modified, mercapto-modified, phenol-modified, and heterofunctional group-modified reactive silicones; polyether-modified, methylstyryl-modified, Non-reactive silicones such as alkyl-modified, fatty acid-modified, alkoxy-modified and fluorine-modified; straight silicones such as dimethyl silicone, methylphenyl silicone, diphenyl silicone, and methylhydrogen silicone.

  Among these silicone oils, alkyl groups, aryl groups, alkyl groups in which some or all of the hydrogen atoms are substituted with fluorine atoms, and silicone oils having hydrogen as a substituent are preferable. Specific examples include dimethyl silicone oil, methylphenyl silicone oil, methyl hydrogen silicone oil, and fluorine-modified silicone oil. These silicone oils may be used alone or as a mixture of two or more.

These silicone oils preferably have a viscosity at 25 ° C. of 5 mm ² / s to 20,000 mm ² / s, more preferably 10 mm ² / s to 1,000 mm ² / s, and even more preferably 20 mm ^2. / S or more and 500 mm ² / s or less. When the viscosity of the silicone oil is within this range, the silica fine particles treated with the silicone oil can easily obtain sufficient hydrophobicity, and the surface treatment can be easily performed without forming an aggregate.

  The silica fine particles A and B used in the present invention have a treatment step of pulverizing the primary treated fine particles after the primary surface treatment, and further subjecting the fine pulverized fine particles to a secondary surface treatment. can do. Note that the crushing treatment may be performed simultaneously with the primary surface treatment.

  The surface treatment with silicone oil and the surface treatment with alkoxysilane or silazane may be either dry treatment or wet treatment.

  The specific procedure for surface treatment with alkoxysilane or silicone oil is, for example, by reacting silica fine particles in a solvent (preferably adjusted to pH 4 with an organic acid, etc.) in which silicone oil is dissolved, and then removing the solvent. And crushing. Subsequently, when performing surface treatment with alkoxysilane or silazane, the specific procedure is to put the crushed treated fine particles in a solvent in which these are dissolved and react, then remove the solvent and crush the treatment. Apply. Further, the following method may be used. For example, in the surface treatment with silicone oil, silica fine particles are put into a reaction vessel. Then, alcohol water is added with stirring in a nitrogen atmosphere, silicone oil is introduced into the reaction tank to perform surface treatment, and the mixture is further heated and stirred to remove the solvent, followed by crushing treatment. In the surface treatment with alkoxysilane or silazane, the surface treatment is performed by introducing alkoxysilane or silazane while stirring in a nitrogen atmosphere, and further, the mixture is heated and stirred to remove the solvent, and then cooled. Further, the surface treatment may be performed as follows. For example, any of silicone oil, alkoxysilane, and silazane and silica fine particles are put into a treatment tank, and the inside of the treatment tank is stirred with a stirring member such as a stirring blade to mix the raw materials. This mixing may be directly mixed using a mixer such as a Henschel mixer. Alternatively, a method of spraying any one of silicone oil, alkoxysilane, and silazane onto silica fine particles may be used. Further, the silica fine particles may be heat-treated at 100 ° C. or higher after being treated with any of silicone oil, alkoxysilane, and silazane.

  In the silane compound treatment used for the surface treatment of the silica fine particles A and B, it is preferable to use 5 parts by mass or more and 40 parts by mass or less of the treating agent with respect to 100 parts by mass of the silica fine particles. More preferably, they are 5 to 35 mass parts, Most preferably, they are 10 to 30 mass parts.

  The methanol wettability of the silica fine particles A and B used in the present invention is preferably 60% by volume or more. When the methanol wettability of the silica fine particles B is 60% by volume or more, the silica fine particles are hydrophobized, making it difficult to absorb moisture, and the charge amount does not decrease when the toner is used for a long time in a high temperature and high humidity environment. More preferably, it is 70% or more, and more preferably 75% or more.

  For the production of the silica fine particles used in the present invention, a known production method such as a wet production method or a dry production method can be used.

For example, by using vapor phase oxidation of a silicon halide compound, silica fine particles called so-called dry silica or fumed silica can be obtained. Specifically, it utilizes a thermal decomposition oxidation reaction of silicon tetrachloride gas in an oxyhydrogen flame, and the basic reaction formula is as follows.
SiCl ₄ + 2H ₂ + O ₂ → SiO ₂ + 4HCl

  In this production process, it is also possible to obtain composite fine particles of silica and other metal oxides by using other metal halogen compounds such as aluminum chloride or titanium chloride together with silicon halogen compounds. These are also included as silica fine particles used in the present invention.

  The wax used in the present invention preferably has an endothermic peak derived from the wax at 60 ° C. or more and 80 ° C. or less in a DSC curve measured by a differential scanning calorimeter (DSC) from the viewpoint of low temperature fixability.

  When the endothermic peak is less than 60 ° C., the low-temperature fixability is excellent, but the wax in the toner becomes very mobile. Therefore, even if the silica fine particles of the present invention are used, when the particles are left in a high temperature and high humidity environment for a long period of time, the exudation of the wax onto the toner particle surfaces cannot be suppressed, and the effects of the present invention are hardly obtained.

  The toner particles are preferably produced by a production method of granulating in an aqueous medium such as suspension polymerization or suspension granulation. Among these, the suspension polymerization method capable of easily producing toner particles having a core / shell structure is suitable in terms of achieving both developability and fixability.

  The toner of the present invention preferably contains a polar resin A which is a styrene resin containing a carboxylic acid group and a polar resin B which is a polyester resin as polar resins.

  The toner particles are produced in an aqueous medium, and by using the polar resins A and B described above as the polar resin, the vicinity of the surface of the toner particles is relatively hard, but the outermost layer has a sharp melt property when heated, In addition, toner particles with soft toner particles can be easily obtained. Specifically, the glass transition point (Tg) of the binder resin forming the inner layer of the toner particles is lowered, or the peak molecular weight (Mp) is lowered. As the outer layer of the toner particles, a sufficient amount of the polar resin A having a Tg or Mp higher than that of the binder resin and the polar resin B having a sharp melt property can be used.

  In addition, if the adhesion between the inner layer (core) and the outer layer (shell) is weak, if the toner continues to be stressed with continuous output, the outer layer peels off or is scraped, and the toner particles have a surface composition at a certain point. It is difficult to obtain high reliability with respect to developability and transferability. Therefore, in the present invention, a polar resin having polarity and compatibility with the core binder resin (core binder) is used as a part of the shell, so that sufficient adhesion with the core is ensured. However, it is important to form a shell. Therefore, the polar resin A contains a styrenic material that is suitably used in the suspension polymerization method, which is a preferred production method of the present invention.

  The polar resin B is a polyester resin. In particular, by controlling the relationship of the interfacial tension described later, it is possible to take a preferred shell form in the present invention in which the polar resin B is held on the surface of the toner particle and the polar resin A is present on the inner layer thereof. Become.

  When the toner particles used in the present invention are produced by suspension polymerization, it is preferable to add polar resins A and B during the polymerization reaction from the dispersion step to the polymerization step. In that case, the presence state of the polar resin can be controlled according to the balance of polarity exhibited by the polymerizable monomer composition serving as toner particles and the aqueous dispersion medium. That is, it is possible to form a shell of a thin layer of polar resin on the surface of the toner particles, or to make the polar resin exist with a gradient from the toner particle surface toward the center. In addition, the strength of the shell portion of the core-shell structure can be freely controlled by adding the polar resin. Therefore, it is possible to optimize the durability and fixability of the toner.

  By adopting the toner design as described above, since the phase separation occurs while the polar resin A is compatible in the binder resin, the respective components are compatible at the interface between the inner layer and the outer layer and have high adhesion. Toner particles having a core / shell structure can be obtained. In addition, the adhesion between the polar resins A and B is sufficient. The reason is not clear, but it is thought to be due to the interaction at the polar group part of the polar resin. In addition, it is possible to obtain a toner having a highly adhesive core / shell structure in which the polarity continuously increases from the inner layer to the outer layer of the toner particles. As a result, it is possible to easily achieve both development durability, toner storage stability and low-temperature fixability.

  The polar resin A used in the present invention is a polymer of a nitrogen-containing monomer such as dimethylaminoethyl methacrylate or diethylaminoethyl methacrylate, or a copolymer of a nitrogen-containing monomer and a styrene-unsaturated carboxylic acid ester. Nitrile monomers such as acrylonitrile; halogen-containing monomers such as vinyl chloride; unsaturated carboxylic acids such as acrylic acid and methacrylic acid; unsaturated dibasic acids; unsaturated dibasic acid anhydrides; Polymer of monomer or styrene monomer, styrene-acrylic acid copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid ester copolymer, styrene-maleic acid Copolymers with styrene copolymers such as acid copolymers; polyesters; epoxy resins.

  In particular, when a styrene-methacrylic acid copolymer or a styrene-acrylic copolymer is used and a toner is produced by suspension polymerization using a vinyl-based polymerizable monomer, the phase of the toner and the binder resin is reduced. This is preferable because the solubility is further improved.

  Moreover, when using a styrene-type copolymer, it is preferable that residual styrene is the range of 0-300 ppm in order to make familiarity with polar resin and binder resin favorable.

  The polar resin A preferably has a weight average molecular weight Mw (A) measured by gel permeation chromatography (GPC) of 8,000 to 50,000. Moreover, what has ratio (Mw / Mn) of a number average molecular weight (Mn) and a weight average molecular weight (Mw) is 1.05-5.00 is preferable. More preferably, the weight average molecular weight Mw (A) is 10,000 to 30,000.

  Moreover, what is 80-100 degreeC is preferable for glass transition point Tg (A). Furthermore, the acid value Av (A) is preferably 5 to 30 mgKOH / g, and the hydroxyl value OHv (A) is preferably 5 to 50 mgKOH / g. In that case, it is preferable to have an acid value and a hydroxyl value simultaneously.

  The content of the polar resin A is preferably 5 to 40 parts by mass with respect to 100 parts by mass of the polymerizable monomer or the binder resin. More preferably, it is 5-30 mass parts.

  The polar resin B used in the present invention has a peak molecular weight Mp (B) measured by GPC of 5,000 to 20,000. Moreover, what is 60-80 degreeC is preferable for glass transition point Tg (B).

  The content of the polar resin B is preferably 1 to 15 parts by mass with respect to 100 parts by mass of the polymerizable monomer or the binder resin. More preferably, it is 3-10 mass parts.

  As the polar resin B used in the present invention, either one or both of a saturated polyester resin and an unsaturated polyester resin can be appropriately selected and used.

  The alcohol component and acid component which comprise the said polyester resin are illustrated below. As alcohol components, ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexane Diol, neopentyl glycol, 2-ethyl-1,3-hexanediol, cyclohexanedimethanol, butenediol, octenediol, cyclohexenedimethanol, hydrogenated bisphenol A, and bisphenol derivatives represented by the following general formula (I):

（式中、Ｒはエチレンまたはプロピレン基であり、ｘ，ｙはそれぞれ１以上の整数であり、かつｘ＋ｙの平均値は２〜１０である。）
あるいは一般式（Ｉ）の化合物の水添物、また、下記一般式（ＩＩ）で示されるジオール、

(In the formula, R is an ethylene or propylene group, x and y are each an integer of 1 or more, and the average value of x + y is 2 to 10.)
Alternatively, a hydrogenated compound of the compound of the general formula (I), a diol represented by the following general formula (II),

あるいは式（ＩＩ）の化合物の水添物のジオール、さらには、グリセリン、ペンタエリスリトール、ソルビット、ソルビタン、ノボラック型フェノール樹脂のオキシアルキレンエーテルなどの多価アルコール等が挙げられる。

Or the diol of the hydrogenated compound of the compound of Formula (II), Furthermore, polyhydric alcohols, such as oxyalkylene ether of glycerol, pentaerythritol, sorbit, sorbitan, a novolak-type phenol resin, etc. are mentioned.

  Examples of the divalent carboxylic acid include the following. Benzene dicarboxylic acid such as phthalic acid, terephthalic acid, isophthalic acid, and phthalic anhydride or its anhydride, alkyl dicarboxylic acid such as succinic acid, adipic acid, sebacic acid, azelaic acid or its anhydride, and further 6 to 18 carbon atoms. Succinic acid substituted with alkyl or alkenyl groups or anhydrides thereof, unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid, itaconic acid or anhydrides thereof, and trimellitic acid, pyromellitic acid, 1 , 2,3,4-butanetetracarboxylic acid, polyvalent carboxylic acids such as benzophenone tetracarboxylic acid and their anhydrides.

  The toner of the present invention preferably contains a polar resin C which is a polymer having a sulfonic acid group, a sulfonic acid group or a sulfonic acid ester group.

  By including the polar resin C, it is possible to further improve both the durability and the fixing property of the toner and the storage stability. Further, the charge controllability is improved, the toner coat amount in the longitudinal direction of the toner carrier is made uniform, and development on the photoreceptor can be performed more faithfully. Also, high in-page uniformity can be obtained. In addition to this, even with a transfer material having low smoothness, transfer uniformity similar to that of a transfer material having high smoothness can be obtained. In addition, when toner particles are produced by a suspension polymerization method, the granulation stability in an aqueous medium can be improved.

  In particular, when the toner of the present invention is produced by a suspension polymerization method, the addition of the polar resin C promotes the core-shell structure of the toner particles in the polymerization stage as well as stabilizing the granulation. For this reason, both the durability and the fixing property of the toner and the storage stability are further enhanced.

  Examples of the monomer having a sulfonic acid group, a sulfonic acid group salt, or a sulfonic acid ester group for producing the polar resin C include styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, and 2-methacrylamide. Examples include 2-methylpropane sulfonic acid, vinyl sulfonic acid, and methacryl sulfonic acid. And what made the sulfonic acid group which these monomers have into a salt, and the compound esterified by the methyl group and the ethyl group can also be used.

  The polar resin C used in the present invention may be a homopolymer of the above monomer, but may be a copolymer of the above monomer and another monomer. As a monomer that forms a copolymer with the above monomer, there is a vinyl polymerizable monomer, and a monofunctional polymerizable monomer or a polyfunctional polymerizable monomer can be used.

  The polar resin C preferably has a glass transition point Tg (C) of 70 to 90 ° C.

  The polar resin C is preferably contained in an amount of 0.1 to 3.0 parts by mass with respect to 100 parts by mass of the binder resin.

  The polar resin C is preferably a styrene polymer or copolymer having a peak molecular weight (Mp) of 12,000 or more and 28,000 or less. By setting the peak molecular weight (Mp) of the polar resin C to 12,000 or more and 28,000 or less, the compatibility with the binder resin, the polar resin A, and the polar resin B and the layer separation proceed appropriately, and a more preferable core / shell structure is obtained. I can do it.

  In order to obtain a good fixed image, the toner of the present invention preferably contains 0.5 to 50 parts by mass, preferably 3 to 30 parts by mass of a wax component with respect to 100 parts by mass of the binder resin. More preferably, it is 5 mass parts-20 mass parts. If the content of the wax component is within the above range, low temperature offset can be satisfactorily suppressed while maintaining long-term storage stability. Also, good fluidity and image characteristics can be maintained without disturbing the dispersion of other toner materials.

  Examples of the wax component that can be used in the toner of the present invention include the following. Petroleum waxes such as paraffin wax, microcrystalline wax, petrolactam and derivatives thereof; montan wax and derivatives thereof; hydrocarbon waxes and derivatives thereof according to the Fischer-Tropsch method; polyolefin waxes and derivatives thereof such as polyethylene wax and polypropylene wax; carnauba wax Natural waxes such as candelilla wax and derivatives thereof. These derivatives include oxides, block copolymers with vinyl monomers, and graft modified products. Furthermore, fatty acids such as higher aliphatic alcohols, stearic acid and palmitic acid, or compounds thereof, acid amide waxes, ester waxes, ketones, hydrogenated castor oil and derivatives thereof, plant waxes, and animal waxes. Of these, ester wax and hydrocarbon wax are particularly preferred from the viewpoint of excellent releasability.

  In particular, it is preferable that two types of waxes, ester wax and hydrocarbon wax, are used in combination, and the total content of ester wax and hydrocarbon wax is based on 100 parts by mass of the polymerizable monomer or binder resin. It is preferably 1 part by mass or more and 30 parts by mass or less. The mass part of the binder resin here is the mass part of the polymerizable monomer when the toner particles are produced in an aqueous medium.

  The mass ratio of the content of ester wax and hydrocarbon wax (ester wax: hydrocarbon wax) is preferably (95: 5) to (60:40).

  When producing toner particles by the suspension polymerization method, it is considered that Tg increases due to the compatibility of the polar resin (shell binder) to be added. Specifically, it is preferable that the theoretical Tg of the monomer for producing the binder resin (core binder) is set to be low so that the Tg of the manufactured toner is within a predetermined range. When designed with a low theoretical Tg, the heat resistance (blocking resistance) tends to decrease, but by designing in this way, the decrease in heat resistance can be suppressed. Further, improvement in developability, transferability and fixability can be achieved, and better characteristics than conventional toner can be obtained. In this invention, it is preferable that Tg of binder resin (core binder) is 10-45 degreeC, More preferably, it is 15-40 degreeC.

  Although the reason is not clear, it is preferable to add an aromatic organic solvent (for example, toluene or xylene) to the monomer when the toner particles are produced by the suspension polymerization method. While the shell binder is compatible with the binder resin (core binder), phase separation is promoted, and the effects of the present invention are easily exhibited.

  Examples of the binder resin (core binder) used in the present invention include styrene-acrylic copolymers, styrene-methacrylic copolymers, epoxy resins, and styrene-butadiene copolymers. Examples of the polymerizable monomer used in the production of the binder resin include vinyl polymerizable monomers capable of radical polymerization. As the vinyl polymerizable monomer, a monofunctional polymerizable monomer or a polyfunctional polymerizable monomer can be used.

  Examples of the binder resin (core binder) used in the present invention include styrene-acrylic copolymers, styrene-methacrylic copolymers, epoxy resins, and styrene-butadiene copolymers. Examples of the polymerizable monomer used in the production of the binder resin include vinyl polymerizable monomers capable of radical polymerization. As the vinyl polymerizable monomer, a monofunctional polymerizable monomer or a polyfunctional polymerizable monomer can be used.

  Examples of the vinyl polymerizable monomer include the following.

  Styrene; Styrenic monomers such as o- (m-, p-) methylstyrene, m- (p-) ethylstyrene; methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, Propyl methacrylate, butyl acrylate, butyl methacrylate, octyl acrylate, octyl methacrylate, dodecyl acrylate, dodecyl methacrylate, stearyl acrylate, stearyl methacrylate, behenyl acrylate, behenyl methacrylate, 2-ethylhexyl acrylate, Acrylic acid ester monomers such as 2-ethylhexyl methacrylate, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, etc. Ether-based monomers; butadiene, isoprene, cyclohexene, acrylonitrile, methacrylonitrile, acrylic acid amide, ene-based monomers such as methacrylic acid amide.

  These may be used alone or in general by appropriately mixing monomers with reference to the theoretical glass transition temperature (Tg) described in the publication Polymer Handbook 2nd edition III-p139-192 (manufactured by John Wiley & Sons). Used.

  In the present invention, the weight average particle diameter (D4) of the toner is preferably 3.0 to 8.0 μm.

  The weight average particle diameter (D4) of the toner can be satisfied by adjusting the particle size in a particle size adjusting process such as air classification and sieving at the time of toner production. In the case of a polymerized toner which is a preferred form of the present invention, it can be adjusted by the amount of the dispersion stabilizer charged.

  The average circularity of the toner of the present invention is preferably 0.960 to 1.000. If it is within this range, the contact area between the toner and the photoconductor is small, and the adhesion of the toner to the photoconductor due to mirror image force, van der Waals force, etc. is reduced, so that high transferability is obtained. Can do. Further, the toner coating amount in the longitudinal direction of the toner carrying member becomes uniform, and the electrostatic latent image on the photosensitive member can be faithfully developed with the toner.

  The number of particles having a circularity of less than 0.960 is preferably 2 to 30% by number. By controlling within this range, it is possible to prevent embedding of the external additive due to the toner being easily clogged in the developing device. When a large number of images having a high printing ratio such as photographic images are output, it is possible to suppress density fluctuation due to insufficient supply of toner onto the developer carrying member. In addition, it is possible to suppress poor cleaning due to an increase in the amount of residual toner, and to stably obtain an image faithful to the electrostatic latent image even with a large number of output sheets.

  The number of particles less than 2 μm of the toner is preferably 2 to 20% by number. By controlling within this range, it is possible to prevent embedding of the external additive due to the toner being easily clogged in the developing device. When a large number of images having a high printing ratio such as photographic images are output, it is possible to suppress density fluctuation due to insufficient supply of toner onto the developer carrying member. In addition, toner fusion to each member such as a developer carrier and an electrostatic latent image carrier is suppressed, and image defects such as toner adhering to a non-image portion such as a fog or a spot can be prevented. It becomes possible.

The average circularity is
(1) When the toner is produced by suspension polymerization, the pH in the aqueous medium during granulation is controlled.
(2) The toner is spheroidized by heat in an aqueous medium.
(3) The toner is spheroidized by a mechanical method.
Thus, the above range can be satisfied. The number of particles having a degree of circularity of less than 0.960 and the number of particles of less than 2 μm can satisfy the above range by controlling the acid value and hydroxyl value of a polar resin described later.

  In the present invention, the main peak molecular weight Mp in GPC of the tetrahydrofuran (THF) soluble part of the toner is preferably 10,000 to 40,000, more preferably 15,000 to 35,000. When the main peak molecular weight is within the above range, the oozing out of the wax becomes appropriate and good high temperature offset resistance can be obtained. Moreover, since it has moderate strength, good developability and transferability can be obtained. Further, excellent characteristics can be obtained with respect to low-temperature fixability.

  It should be noted that the above-described conditions regarding the main peak molecular weight Mp of the toner can be satisfied by adjusting the temperature at the time of toner production. In particular, when a toner is produced by a polymerization method which is a preferred production method of the present invention, it can be satisfied by adjusting the polymerization conditions (temperature, initiator type, initiator amount).

  The toner of the present invention preferably has a glass transition temperature (Tg) of 30 to 58 ° C. measured by a differential scanning calorimeter. More preferably, it is 40-55 degreeC.

The toner of the present invention preferably has a melt viscosity at 100 ° C. measured by a constant load extrusion type capillary rheometer of 5.00 × 10 ^{3 to} 3.50 × 10 ⁴ Pa · s. When the melt viscosity of the toner is within the above range, the oozing out of the wax becomes appropriate, and better high temperature offset resistance can be obtained. Moreover, since moderate toughness is maintained, developability and transferability become better. Furthermore, since the adhesive force with the transfer paper becomes appropriate, a better effect can be obtained with respect to the low-temperature fixing property and the winding property. Further, it becomes easier to obtain a fixed image having high glossiness.

  In addition, the said melt viscosity can satisfy | fill conditions by adjusting the molecular weight and glass transition temperature of binder resin, or adjusting the kind and content of a wax component. Moreover, it is also possible to adjust with the kind and content of polar resin A, B, C. Furthermore, in the case of the polymerized toner which is a preferred embodiment of the present invention, it is possible to adjust the polymerization conditions (temperature, initiator type, initiator amount).

  In the present invention, a crosslinking agent may be used for the purpose of increasing the mechanical strength of the toner while maintaining a low Tg of the core portion of the toner particles.

  The cross-linking agent used in the present invention is preferably divinylbenzene, but the following cross-linking agents can also be used.

  Examples of the bifunctional crosslinking agent include the following. Bis (4-acryloxypolyethoxyphenyl) propane, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol Diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 200, # 400, # 600 diacrylate, dipropylene glycol diacrylate, polypropylene glycol diacrylate , Polyester type diacrylate (MANDA Nippon Kayaku), and dimethacrylate replaced with dimethacrylate.

  The following are mentioned as a polyfunctional crosslinking agent. Pentaerythritol triacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate and its methacrylate, 2,2-bis (4-methacryloxypolyethoxyphenyl) propane, diallyl phthalate, tri Allyl cyanurate, triallyl isocyanurate and triallyl trimellitate.

  The addition amount of these crosslinking agents is preferably 0.001 to 1.000 parts by mass, more preferably 0.010 to 0.500 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

  The following are mentioned as a polymerization initiator used for this invention. 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis Azo or diazo polymerization initiators such as -4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile; benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl Peroxide-based polymerization initiators such as peroxide, lauroyl peroxide, and tert-butyl-peroxypivalate.

  Although the usage-amount of these polymerization initiators changes with the target degree of polymerization, generally it is 3-20 mass parts with respect to 100 mass parts of said polymerizable monomers. The kind of the polymerization initiator varies slightly depending on the polymerization method, but is selected with reference to the 10-hour half-life temperature, and used alone or in combination.

  Examples of the colorant preferably used in the present invention include the following organic pigments or dyes and inorganic pigments.

  As an organic pigment or organic dye as a cyan colorant, a copper phthalocyanine compound and a derivative thereof, an anthraquinone compound, or a basic dye lake compound can be used.

  Specific examples include the following. C. I. Pigment blue 1, C.I. I. Pigment blue 7, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 1, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 60, C.I. I. Pigment blue 62, C.I. I. Pigment Blue 66.

  Examples of the organic pigment or organic dye as the magenta colorant include the following. Condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, perylene compounds.

  Specific examples include the following. C. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment violet 19, C.I. I. Pigment red 23, C.I. I. Pigment red 48: 2, C.I. I. Pigment red 48: 3, C.I. I. Pigment red 48: 4, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 81: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 144, C.I. I. Pigment red 146, C.I. I. Pigment red 150, C.I. I. Pigment red 166, C.I. I. Pigment red 169, C.I. I. Pigment red 177, C.I. I. Pigment red 184, C.I. I. Pigment red 185, C.I. I. Pigment red 202, C.I. I. Pigment red 206, C.I. I. Pigment red 220, C.I. I. Pigment red 221, C.I. I. Pigment Red 254.

  As the organic pigment or organic dye as the yellow colorant, compounds represented by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds are used.

  Specific examples include the following. C. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 62, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 109, C.I. I. Pigment yellow 110, C.I. I. Pigment yellow 111, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 127, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 129, C.I. I. Pigment yellow 147, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 168, C.I. I. Pigment yellow 174, C.I. I. Pigment yellow 175, C.I. I. Pigment yellow 176, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 181, C.I. I. Pigment yellow 191, C.I. I. Pigment Yellow 194.

  As the black colorant, carbon black and carbon black that is toned to black using the yellow / magenta / cyan colorant are used.

  These colorants can be used alone or mixed and further used in the form of a solid solution. The colorant used in the toner of the present invention is selected from the viewpoints of hue angle, saturation, brightness, light resistance, OHP transparency, and dispersibility in the toner.

  The colorant is preferably used by adding 1 to 20 parts by mass with respect to 100 parts by mass of the binder resin.

  In the present invention, when a toner is obtained using a polymerization method, it is necessary to pay attention to the polymerization inhibitory property and water phase transfer property of the colorant. Therefore, it is preferable that the colorant be subjected to surface modification, for example, a hydrophobic treatment with a substance that does not inhibit polymerization. In particular, dyes and carbon blacks have many polymerization inhibiting properties, so care must be taken when using them.

  Examples of a method for suppressing the polymerization inhibitory property of the dye-based colorant include a method in which a polymerizable monomer is polymerized in the presence of these dyes in advance, and the obtained colored polymer is used as a polymerizable monomer composition. Added.

  Moreover, about carbon black, you may process with the substance which reacts with the surface functional group of carbon black other than the process similar to the said dye, for example, polyorganosiloxane.

  In the toner of the present invention, a charge control agent can be mixed with toner particles as necessary. By adding a charge control agent, the charge characteristics can be stabilized, and the optimum triboelectric charge amount can be controlled according to the development system.

  As the charge control agent, known ones can be used, and in particular, a charge control agent that has a high frictional charging speed and can stably maintain a constant triboelectric charge amount is preferable. Further, when the toner is produced by a direct polymerization method, a charge control agent having a low polymerization inhibitory property and substantially free from a solubilized product in an aqueous dispersion medium is particularly preferable.

  Examples of the charge control agent that control the toner to be negatively charged include organometallic compounds and chelate compounds. Examples thereof include monoazo metal compounds, acetylacetone metal compounds, aromatic oxycarboxylic acids, aromatic dicarboxylic acids, oxycarboxylic acids, and dicarboxylic acid-based metal compounds. Others include aromatic oxycarboxylic acids, aromatic mono- and polycarboxylic anhydrides, esters, phenol derivatives such as bisphenol. Furthermore, urea derivatives, metal-containing naphthoic acid compounds, boron compounds, quaternary ammonium salts, calixarene, and resin charge control agents can be mentioned.

  On the other hand, examples of the charge control agent that control the toner to be positively charged include the following. Nigrosine modified products with nigrosine and fatty acid metal salts; guanidine compounds; imidazole compounds; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and the like Some onium salts such as phosphonium salts and their lake pigments; triphenylmethane dyes and their lake pigments (as rake agents, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid , Ferricyanides, ferrocyanides); metal salts of higher fatty acids; resin-based charge control agents.

  The toner of the present invention can contain these charge control agents alone or in combination of two or more.

  Among these charge control agents, a salicylic acid-based compound containing a metal is preferable, and the metal is particularly preferably aluminum or zirconium. The most preferred charge control agent is an aluminum 3,5-di-tert-butylsalicylate compound.

  A preferable blending amount of the charge control agent is 0.01 to 20.00 parts by mass, and more preferably 0.50 to 10.00 parts by mass with respect to 100 parts by mass of the binder resin. However, in the toner of the present invention, it is not always necessary to include a charge control agent in the toner by actively utilizing frictional charging with the toner layer thickness regulating member or the toner carrier.

  In addition to silica fine particles, the toner of the present invention may be used in combination with inorganic fine powder for the purpose of improving fluidity. Silica fine powder and fine powder of titanium oxide, alumina or their double oxide can be used in combination. As the inorganic fine powder used in combination, titanium oxide is preferable.

  The inorganic fine powder other than the silica fine particles is added for improving the fluidity of the toner and making the toner particles triboelectrically charged. Hydrophobic treatment of inorganic fine powder can provide functions such as adjustment of triboelectric charge amount of toner, improvement of environmental stability, improvement of characteristics under high humidity environment, etc. It is preferable to use inorganic fine powder. When the inorganic fine powder externally added to the toner particles absorbs moisture, the amount of triboelectric charge as the toner decreases, and the developability and transferability tend to decrease.

  Examples of the treatment agent for the hydrophobic treatment of the inorganic fine powder include the following.

  Unmodified silicone varnish, various modified silicone varnishes, unmodified silicone oil, various modified silicone oils, silane compounds, silane coupling agents, other organosilicon compounds, and organotitanium compounds. These treatment agents may be used alone or in combination.

  Hereinafter, the method for producing the toner particles will be described by exemplifying a suspension polymerization method suitable for obtaining the toner particles used in the present invention.

  The toner particles include a polymerizable monomer, a colorant, a wax component and other additives as necessary used in the production of the binder resin, and a disperser such as a homogenizer, a ball mill, a colloid mill, or an ultrasonic disperser. Or evenly dissolved or dispersed. In particular, the colorant-containing monomer and the resin obtained in the dispersion step after passing through the dispersion step of obtaining a colorant-containing monomer by dispersing at least the colorant in the polymerizable monomer by a known dispersion method It is preferable to perform the adjustment process of mixing. A polymerization initiator is dissolved in this, and a polymerizable monomer composition is prepared.

  Next, toner particles are manufactured by suspending the polymerizable monomer composition in an aqueous medium containing a dispersant and performing polymerization. The polymerization initiator may be added simultaneously with the addition of other additives to the polymerizable monomer, or may be mixed immediately before being suspended in the aqueous medium. Also, a polymerization initiator dissolved in a polymerizable monomer or solvent can be added immediately after granulation and before starting the polymerization reaction.

  As the dispersant, known inorganic and organic dispersants can be used.

  Specifically, examples of the inorganic dispersant include the following. Tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, magnesium carbonate, calcium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina .

  On the other hand, examples of the organic dispersant include the following. Polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, carboxymethyl cellulose sodium salt, starch.

  Further, commercially available nonionic, anionic and cationic surfactants can be used as the dispersant. Examples of such surfactants include the following. Sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, calcium oleate.

  As the dispersant, an inorganic poorly water-soluble dispersant is preferable, and it is preferable to use a poorly water-soluble inorganic dispersant that is soluble in an acid.

  In the present invention, when preparing an aqueous dispersion medium using a hardly water-soluble inorganic dispersant, the amount of these dispersants used is 0.2 to 100 parts by mass with respect to 100 parts by mass of the polymerizable monomer. It is preferable that it is 2.0 mass parts. Moreover, in this invention, it is preferable to prepare an aqueous dispersion medium using 300-3,000 mass parts water with respect to 100 mass parts of polymerizable monomer compositions.

  In the present invention, when preparing an aqueous dispersion medium in which the poorly water-soluble inorganic dispersant as described above is dispersed, a commercially available dispersant may be used as it is. In addition, in order to obtain dispersant particles having a fine uniform particle size, the above water-insoluble inorganic dispersant may be produced in a liquid medium such as water under high speed stirring to prepare an aqueous dispersion medium. For example, when tricalcium phosphate is used as a dispersant, it is possible to form a tricalcium phosphate microparticle by mixing a sodium phosphate aqueous solution and a calcium chloride aqueous solution under high-speed stirring.

<Measurement of toner glass transition point (Tg)>
The toner Tg measurement method in the present invention basically uses the same apparatus as the method for obtaining the solubility of ester wax in a polar resin. However, since the DSC melting point peak of the wax and the Tg of the toner overlap during heating, the modulated mode is used in the toner of the present invention. Measurement is performed under the following conditions, and the glass transition point is obtained from the peak position of the DSC curve at the first temperature increase. In addition, the glass transition temperature of core binder resin and the glass transition temperature of shell binder resin (polar resin A, B) are measured similarly. Regarding the glass transition temperature of the core binder resin, since it is difficult to isolate only the binder resin (core binder) from the toner particles, the theoretical Tg calculated from the formulation is the Tg of the binder resin (core binder). May be considered.

<Measurement conditions>
• Equilibrate at 20 ° C for 5 minutes.
・ Modulation of 1.0 ° C / min is applied, and the temperature is increased to 140 ° C at 1 ° C / min.
• Equilibrate at 140 ° C for 5 minutes.
-Lower the temperature to 20 ° C.

  The glass transition temperature (Tg) here is determined by the midpoint method. Further, the peak temperature (P1) of the maximum endothermic peak of the toner is a temperature showing a maximum value in the endothermic peak. When there are a plurality of endothermic peaks, the highest endothermic peak is the one having the highest height from the baseline in the region above the endothermic peak.

<Measurement of molecular weight>
In the present invention, the main peak molecular weight of the THF soluble matter of the toner and the main peak molecular weights (MpA, MpB, MpC) of the polar resins A, B, and C are measured by the following methods.

  The measurement sample is prepared as follows.

  The sample and THF are mixed at a concentration of about 0.5 to 5 mg / ml (for example, about 5 mg / ml) and left at room temperature for several hours (for example, 5 to 6 hours). Next, shake well and mix the THF and sample well (until the sample is no longer united), and then let stand at room temperature for 12 hours or longer (for example, 24 hours). At this time, the time from the start of mixing the sample and THF to the end of standing is set to 24 hours or longer. Thereafter, a sample processing filter (pore size 0.45 to 0.5 μm, for example, Mysori Disc H-25-2 manufactured by Tosoh Corp., Excro Disc 25CR manufactured by Gelman Science Japan Co., Ltd. can be preferably used) is passed through GPC. A sample is used. The sample concentration is adjusted so that the resin component is 0.5 to 5 mg / ml. In addition, when the resin does not dissolve in THF or is difficult to dissolve, it is possible to use a basic solvent such as DMF. Furthermore, as for the polar resin C of the present invention, for those containing sulfonic acid groups, the column elution rate depends also on the amount of sulfonic acid groups, so that the accurate molecular weight and molecular weight distribution were measured. Must not. Therefore, it is necessary to prepare a sample in which sulfonic acid groups are capped in advance. Methyl esterification is preferable for capping, and a commercially available methyl esterifying agent can be used. Specifically, a method of treating with trimethylsilyldiazomethane can be mentioned.

<Measurement conditions>
Equipment: High-speed GPC “HLC8120 GPC” (manufactured by Tosoh Corporation)
Column: Seven series of Shodex KF-801, 802, 803, 804, 805, 806, 807 (manufactured by Showa Denko KK)
Eluent: tetrahydrofuran (THF) or DMF if the resin is difficult to dissolve
Flow rate: 1.0 ml / min
Oven temperature: 40.0 ° C
Sample injection volume: 0.10 ml

  In calculating the molecular weight of the sample, standard polystyrene resin (TSO standard polystyrene F-850, F-450, F-288, F-128, F-80, F-40, F-20, F- manufactured by Tosoh Corporation) was used. 10, F-4, F-2, F-1, A-5000, A-2500, A-1000, A-500).

<Measurement of Acid Value Av (mgKOH / g)>
In the present invention, the acid value Av of the carboxyl group-containing styrene resin is measured by the following method based on JIS K 0070-1992. The same applies to the measurement of the acid value of the polyester resin.

(Sample preparation)
Weigh accurately 1.0 g of sample in a 200 ml beaker, dissolve in 120 ml of toluene while stirring with a stirrer, and add 30 ml of ethanol. The weight of the accurately weighed sample is defined as W (g).

(apparatus)
As an apparatus, a potentiometric automatic titrator AT-400WIN (manufactured by Kyoto Electronics Industry Co., Ltd.) is used. The setting of the apparatus is intended for a sample dissolved in an organic solvent. The glass electrode and the comparative electrode to be used should be compatible with organic solvents. As the pH glass electrode, for example, product code # 100-H112 (manufactured by Kyoto Electronics Industry Co., Ltd.) is used. In addition, the tip must not be dried. A product code # 100-R115 (manufactured by Kyoto Electronics Co., Ltd.) is used for the cork-type reference electrode. In addition, the tip must not be dried. Check if the internal liquid is filled up to the internal liquid replenishment port. Use 3.3M KCl solution as the internal solution.

(procedure)
The adjusted sample is set in the autosampler of the apparatus, and the electrode is immersed in the sample solution. Next, a titrant (1 / 10N KOH (ethanol solution)) is set on the sample solution, and 0.05 mL is added dropwise by automatic intermittent titration to calculate the acid value. The amount of KOH solution used at this time is set to S (mL), and a blank is measured at the same time. The amount of KOH solution used at this time is set to B (mL). The acid value is calculated from the obtained result by the following formula. f is a factor of KOH.
Acid value (mgKOH / g) = {(SB) × f × 5.61} / W

<Measurement of hydroxyl value OHv (mgKOH / g)>
In the present invention, the hydroxyl value OHv (JIS hydroxyl value) of the carboxyl group-containing styrene resin is determined by the following method. The hydroxyl value is the number of mg of potassium hydroxide required to neutralize acetic acid bonded to a hydroxyl group when 1 g of a sample is acetylated. The hydroxyl value of the binder resin is measured according to JIS K 0070-1992. Specifically, it is measured according to the following procedure.

(A) Preparation of reagent 25 g of special grade acetic anhydride is placed in a 100 mL volumetric flask, pyridine is added to make the total volume 100 mL, and shaken sufficiently to obtain an acetylating reagent. The obtained acetylating reagent is stored in a brown bottle so as not to come into contact with moisture, carbon dioxide gas and the like. Dissolve 1.0 g of phenolphthalein in 90 ml of ethyl alcohol (95 vol%), add ion exchange water to make 100 mL, and obtain a phenolphthalein solution. Dissolve 35 g of special grade potassium hydroxide in 20 ml of water, add ethyl alcohol (95 vol%) to 1 L. In order not to touch carbon dioxide, etc., put in an alkali-resistant container and let stand for 3 days, then filter to obtain a potassium hydroxide solution. The obtained potassium hydroxide solution is stored in an alkali-resistant container. Factor of the potassium hydroxide solution is that 25 ml of 0.5 mol / L hydrochloric acid is placed in an Erlenmeyer flask, a few drops of the phenolphthalein solution is added, titrated with the potassium hydroxide solution, and the potassium hydroxide required for neutralization. Determine from the amount of solution. As the 0.5 mol / L hydrochloric acid, one prepared according to JIS K 8001-1998 is used.

(A) Operation (A) Main test 1.0 g of the pulverized resin is precisely weighed in a 200 mL round bottom flask, and 5.0 mL of the acetylating reagent is accurately added to this using a whole pipette. At this time, if the sample is difficult to dissolve in the acetylating reagent, a small amount of special grade toluene is added and dissolved. A small funnel is placed on the mouth of the flask, and the bottom of the flask is immersed in a glycerin bath at about 97 ° C. and heated. At this time, in order to prevent the temperature of the neck of the flask from rising due to the heat of the bath, it is preferable to cover the base of the neck of the flask with a cardboard having a round hole.

  After 1 hour, the flask is removed from the glycerin bath and allowed to cool. After standing to cool, 1 mL of water is added from the funnel and shaken to hydrolyze acetic anhydride. The flask is again heated in the glycerin bath for 10 minutes for further complete hydrolysis. After cooling, wash the funnel and flask walls with 5 ml of ethyl alcohol. Add several drops of the phenolphthalein solution as an indicator and titrate with the potassium hydroxide solution. The end point of titration is when the light red color of the indicator lasts for about 30 seconds.

(B) Blank test Titration similar to the above operation is performed except that no binder resin sample is used.

(C) Substituting the obtained results into the following equation to calculate the hydroxyl value.
A = [{(BC) × 28.05 × f} / S] + D

  Here, A: hydroxyl value (mg KOH / g), B: addition amount (ml) of potassium hydroxide solution in blank test, C: addition amount (ml) of potassium hydroxide solution in this test, f: potassium hydroxide Factor of solution, S: sample (g), D: acid value of binder resin (mgKOH / g).

<Measurement of weight average particle diameter (D4)>
In the present invention, the weight average particle diameter (D4) is measured with a Coulter counter.

  Measurement of toner and toner particle size distribution: As a measuring device, for example, Coulter Counter TA-II, Coulter Multisizer II (Coulter) or Coulter Multisizer III (Coulter) is used. As the electrolyte, first grade sodium chloride is used to prepare an approximately 1% NaCl aqueous solution. For example, ISOTON-II (manufactured by Coulter Scientific Japan) can be used. As a measurement method, 0.1 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 ml of the electrolytic aqueous solution, and 5 mg of a measurement sample (toner and toner particles) is further added. The electrolytic solution in which the sample is suspended is dispersed for about 1 minute with an ultrasonic disperser, and the volume and number of toner particles are measured for each channel using the above-described measuring apparatus using a 100 μm aperture as the aperture. Volume distribution and number distribution are calculated. A weight-average toner weight average particle diameter D4 (μm) obtained from the volume distribution of the toner particles is obtained.

<Measurement of average circularity, number of particles having a circularity of less than 0.960, and number of particles of less than 2 μm>
The average circularity of the toner in the present invention, the number of particles having an average circularity of less than 0.960, and the number of particles of less than 2 μm are measured using a flow type particle image analyzer “FPIA-3000 type” (manufactured by Sysmex). Measured according to the manual.

  The measurement principle of the above apparatus is to take a flowing particle as a still image and perform image analysis. The sample added to the sample chamber is fed into the flat sheath flow cell by a sample suction syringe. The sample fed into the flat sheath flow is sandwiched between sheath liquids to form a flat flow. The sample passing through the flat sheath flow cell is irradiated with strobe light at 1/60 second intervals, and the flowing particles can be photographed as a still image. Further, since the flow is flat, the image is taken in a focused state. The particle image is picked up by a CCD camera, and the picked-up image is image-processed with an image processing resolution of 512 × 512 (0.37 μm × 0.37 μm per pixel), the contour of each particle image is extracted, and the particle image Projected area, perimeter, etc. are measured.

  The image signal is A / D converted by the image processing unit, captured as image data, and image processing for determining the presence or absence of particles is performed on the stored image data. Next, contour enhancement processing is performed as preprocessing for accurately extracting the contour of the particle image. Next, the image data is binarized at an appropriate threshold level.

  Next, it is determined whether each of the binarized particle images is an edge point (contour pixel representing a contour), and in which direction there is an edge point adjacent to the target edge point. Information, that is, chain code is generated.

Next, the projected area S and the perimeter L of each particle image are obtained. Using the projected area S and the perimeter L, the equivalent circle diameter and the circularity are obtained. The equivalent circle diameter is the diameter of a circle having the same area as the projected area of the particle image, and the circularity C is a value obtained by dividing the circumference of the circle obtained from the equivalent circle diameter by the circumference of the projected particle image. And is calculated by the following formula.
Circularity C = 2 × (πS) ^1/2 / L

  When the particle image is circular, the degree of circularity is 1.000, and the degree of circularity becomes smaller as the degree of unevenness on the outer periphery of the particle image increases.

  After calculating the circularity of each particle, the range of the circularity of 0.200 to 1.000 is divided into 800, and the average circularity is calculated by arithmetic mean using the center value of the dividing points and the number of measured particles.

  As a specific measuring method, 10 ml of ion-exchanged water from which impure solids have been previously removed is prepared in a container, and after adding alkylbenzene sulfonate as a dispersant, 0.02 g of a measurement sample is further added. , Uniformly dispersed. As a dispersing means, an ultrasonic disperser UH-50 type (manufactured by SMT) equipped with a titanium alloy chip having a diameter of 5 mm as a vibrator was used and subjected to a dispersion treatment for 5 minutes to obtain a dispersion for measurement. In that case, it cooled suitably so that the temperature of the said dispersion liquid might not become 40 degree | times or more. For the measurement, the above-mentioned flow type particle image analyzer equipped with a standard objective lens (10 times) was used, and a particle sheath “PSE-900A” (manufactured by Sysmex Corporation) was used as the sheath liquid. The dispersion prepared according to the above procedure is introduced into the flow particle image analyzer, and 3000 toner particles are measured in the total count mode in the HPF measurement mode. The binarization threshold at the time of particle analysis was set to 85%, the analysis particle diameter was limited to a circle equivalent diameter of 2.00 μm to 200.00 μm, and the average circularity was determined.

  Further, regarding the number of particles having a circularity of less than 0.960, the analysis particle diameter is limited to the equivalent circle diameter of 2.00 μm to 200.00 μm, and the average circularity is calculated to be limited to 0.960 to 1.000. did.

  In the measurement, automatic focus adjustment was performed using standard latex particles (for example, Duke Scientific 5200A diluted with ion-exchanged water) before the measurement was started. Thereafter, it is preferable to perform focus adjustment every two hours from the start of measurement.

  In the examples of the present application, except for using a flow type particle image analyzer that has been issued a calibration certificate issued by Sysmex Corporation, the analysis particle diameter is limited to an equivalent circle diameter of 2.00 μm to 200.00 μm. Measurements were taken under the measurement and analysis conditions when the calibration certificate was received.

<Measurement of melt viscosity of toner>
The melt viscosity of the toner in the present invention is measured by the following method.

  The viscosity of the toner at 100 ° C. is measured using a constant-load extrusion type capillary rheometer “Flow Characteristic Evaluation Apparatus Flow Tester CFT-500D” (manufactured by Shimadzu Corporation) according to the manual attached to the apparatus. In this device, while applying a constant load from the top of the measurement sample with a piston, the measurement sample filled in the cylinder is heated and melted, and the molten measurement sample is extruded from the die at the bottom of the cylinder, and the temperature at this time And measure the relationship between the amount of piston descent.

  In the present invention, measurement is performed from 50 ° C. to 200 ° C., and the apparent viscosity calculated at 100 ° C. is defined as the viscosity (Pa · s) of the toner at 100 ° C.

The apparent viscosity η (Pa · s) at 100 ° C. is calculated as follows. First, the flow rate Q (cm ³ / s) is calculated from the following equation (4). In the formula, the cross-sectional area of the piston is A (cm ² ), and the time required for the piston to descend between 0.10 mm above and below the position of the piston at 100 ° C. (interval 0.20 mm) is Δt (Seconds).
Q = (0.20 × A) / (10 × Δt) (4)

Then, using the obtained flow rate Q, the apparent viscosity η at 100 ° C. is calculated from the following equation (5). In the formula, the piston load is P (Pa), the diameter of the hole of the die is B (mm), and the length of the die is L (mm).
η = (π × B4 × P) / (128000 × L × Q) (5)

As a measurement sample, about 1.0 g of toner is compression-molded at about 10 MPa using a tablet molding compressor (for example, NT-100H, manufactured by NPA System) in an environment of 25 ° C. for about 60 seconds. A cylindrical shape having a diameter of about 8 mm is used. The measurement conditions of CFT-500D are as follows.
Test mode: Temperature rising start temperature: 50 ° C
Achieving temperature: 200 ° C
Measurement interval: 1.0 ° C
Temperature increase rate: 4.0 ° C./min
Piston cross-sectional area: 1.000 cm ²
Test load (piston load): 10.0 kgf (0.9807 MPa)
Preheating time: 300 seconds Die hole diameter: 1.0 mm
Die length: 1.0mm

<Image forming apparatus configuration>
An overall configuration of an embodiment of an electrophotographic image forming apparatus (image forming apparatus) according to the present invention will be described. FIG. 1 is a cross-sectional view of the image forming apparatus 100 of the present embodiment. The image forming apparatus 100 of this embodiment is a full-color laser beam printer that employs an inline method and an intermediate transfer method. The image forming apparatus 100 can form a full-color image on a recording material (for example, recording paper, plastic sheet, cloth, etc.) according to the image information. The image information is input to the image forming apparatus main body from an image reading apparatus connected to the image forming apparatus main body or a host device such as a personal computer connected to the image forming apparatus main body so as to be communicable.

  The image forming apparatus 100 includes, as a plurality of image forming units, first, second, and third images for forming yellow (Y), magenta (M), cyan (C), and black (K) images, respectively. And fourth image forming units SY, SM, SC, and SK. In the present embodiment, the first to fourth image forming units SY, SM, SC, and SK are arranged in a line in a direction that intersects the vertical direction. In the present embodiment, the configurations and operations of the first to fourth image forming units are substantially the same except that the colors of the images to be formed are different. Therefore, in the following, unless there is a particular distinction, the subscripts Y, M, C, and K given to the reference numerals to indicate that they are elements provided for any color are omitted, and generally explain.

  In this embodiment, the image forming apparatus 100 includes four drum-type electrophotographic photoreceptors, that is, the photoreceptor drums 1 arranged in parallel in a direction intersecting the vertical direction as a plurality of image carriers. The photosensitive drum 1 is rotationally driven by a driving means (drive source) (not shown) in the direction indicated by an arrow A (clockwise). Around the photosensitive drum 1, a charging roller 2 and a scanner unit (exposure device) 3 are arranged. Here, the charging roller 2 is a charging unit that uniformly charges the surface of the photosensitive drum 1. The scanner unit (exposure device) 3 is an exposure unit that forms an electrostatic image (electrostatic latent image) on the photosensitive drum 1 by irradiating a laser based on image information. A developing unit (developing device) 4 and a cleaning member 6 are disposed around the photosensitive drum 1. Here, the developing unit 4 is a developing unit that develops an electrostatic image as a toner image. The cleaning member 6 is a cleaning unit that removes toner (transfer residual toner) remaining on the surface of the photosensitive drum 1 after transfer. Further, an intermediate transfer belt 5 as an intermediate transfer body for transferring the toner image on the photosensitive drum 1 to the recording material 12 is disposed opposite to the four photosensitive drums 1. In the rotation direction of the photosensitive drum 1, the charging position by the charging roller 2, the exposure position by the scanner unit 3, the development position by the development unit 4, the transfer position of the toner image to the intermediate transfer belt 5, and the cleaning position by the cleaning member 6 are They are provided in this order.

  In this embodiment, the developing unit 4 uses a non-magnetic one-component developer, that is, toner, as the developer. In this embodiment, the developing unit 4 performs reverse development by bringing a developing roller (described later) as a developer carrying member into contact with the photosensitive drum 1. That is, in this embodiment, the developing unit 4 is configured to expose the toner charged to the same polarity as the charging polarity of the photosensitive drum 1 (negative polarity in this embodiment) on the photosensitive drum 1 so that the charge is attenuated. It is made to adhere to the part (image part, exposure part) which carried out. As a result, the electrostatic image on the photosensitive drum 1 is developed.

  In this embodiment, the photosensitive drum 1 and the charging roller 2, the developing device 4 and the cleaning member 6 as process means acting on the photosensitive drum 1 are integrally formed into a cartridge to form a process cartridge 7. ing. The process cartridge 7 is attachable to and detachable from the image forming apparatus 100 via mounting means such as a mounting guide and a positioning member provided in the image forming apparatus main body. In this embodiment, the process cartridges 7 for each color all have the same shape, and each of the process cartridges 7 for each color has yellow (Y), magenta (M), cyan (C), and black (K), respectively. ) Is stored. Instead of the configuration of the process cartridge, the developing device 4 may be configured to be detachable from the image forming apparatus main body alone.

  The intermediate transfer belt 5 formed of an endless belt as an intermediate transfer member abuts on all the photosensitive drums 1 and circulates (rotates) in the direction of arrow B (counterclockwise) in the figure. The intermediate transfer belt 5 is stretched around a plurality of support members (a driving roller 51, a secondary transfer counter roller 52, and a tension roller 53).

  On the inner peripheral surface side of the intermediate transfer belt 5, four primary transfer rollers 8 as primary transfer means are arranged in parallel so as to face the respective photosensitive drums 1. The primary transfer roller 8 presses the intermediate transfer belt 5 toward the photosensitive drum 1 to form a nip (primary transfer nip) at the primary transfer portion N1 where the intermediate transfer belt 5 and the photosensitive drum 1 are in contact with each other. A bias having a polarity opposite to the normal charging polarity of the toner is applied to the primary transfer roller 8 from a primary transfer bias power source (high voltage power source) as a primary transfer bias applying unit (not shown). As a result, the toner image on the photosensitive drum 1 is transferred (primary transfer) onto the intermediate transfer belt 5.

  In addition, a secondary transfer roller 9 as a secondary transfer unit is disposed at a position facing the secondary transfer counter roller 52 on the outer peripheral surface side of the intermediate transfer belt 5. The secondary transfer roller 9 is in pressure contact with the secondary transfer counter roller 52 via the intermediate transfer belt 5 and nips (secondary transfer nip) to the secondary transfer portion N2 where the intermediate transfer belt 5 and the secondary transfer roller 9 are in contact with each other. Form. A bias having a polarity opposite to the normal charging polarity of the toner is applied to the secondary transfer roller 9 from a secondary transfer bias power source (high voltage power source) as a secondary transfer bias applying unit (not shown). As a result, the toner image on the intermediate transfer belt 5 is transferred (secondary transfer) to the recording material 12. The primary transfer roller 8 and the secondary transfer roller 9 have the same configuration.

  At the time of image formation, first, the surface of the photosensitive drum 1 is uniformly charged by the charging roller 2. Next, the surface of the charged photosensitive drum 1 is scanned and exposed by laser light corresponding to the image information emitted from the scanner unit 3, and an electrostatic image according to the image information is formed on the photosensitive drum 1. Next, the electrostatic image formed on the photosensitive drum 1 is developed as a toner image by the developing unit 4. The toner image formed on the photosensitive drum 1 is transferred (primary transfer) onto the intermediate transfer belt 5 by the action of the primary transfer roller 8.

  For example, when forming a full-color image, the above-described process is sequentially performed in the first to fourth image forming units SY, SM, SC, and SK, and the toner images of the respective colors are sequentially superimposed on the intermediate transfer belt 5. The primary transfer.

  Thereafter, the recording material 12 is conveyed to the secondary transfer portion N2 in synchronization with the movement of the intermediate transfer belt 5. The four-color toner images on the intermediate transfer belt 5 are collectively transferred onto the recording material 12 by the action of the secondary transfer roller 9 that is in contact with the intermediate transfer belt 5 via the recording material 12. The

  The recording material 12 onto which the toner image has been transferred is conveyed to a fixing device 10 as a fixing unit. The toner image is fixed on the recording material 12 by applying heat and pressure to the recording material 12 in the fixing device 10.

  The primary transfer residual toner remaining on the photosensitive drum 1 after the primary transfer step is removed by the cleaning member 6 and collected in a removed toner chamber (described later). The secondary transfer residual toner remaining on the intermediate transfer belt 5 after the secondary transfer process is cleaned by the intermediate transfer belt cleaning device 11.

  Note that the image forming apparatus 100 can form a single-color or multi-color image using only a desired single or some (not all) image forming units.

<Cleaning configuration of intermediate transfer belt>
Next, cleaning of the intermediate transfer belt in the color image forming apparatus will be described.

  FIG. 2A schematically shows a portion where the intermediate transfer belt cleaning device 11 used in the present embodiment and the intermediate transfer belt 5 are in contact with each other. The intermediate transfer belt cleaning device 11 used an elastic cleaning blade 28 made of urethane rubber. The cleaning blade 28 has a structure in which a rubber part 29 made of urethane rubber is bonded to a sheet metal part 30 made of a plated steel sheet, and the rubber part 29 has a thickness of 2 mm. The rubber part 29 had a hardness of 77 ° according to JIS K6253 standard. The cleaning blade 28 is configured to swing, and the cleaning shaft is fixed around the swing shaft 32 by fixing the swing shaft 32 to an intermediate transfer belt unit (not shown) and pressurizing the sheet metal 30 with a pressure spring 31. 28 moves. A tension roller 53 is disposed inside the intermediate transfer belt 5 so as to face the rubber part 29. The cleaning blade 28 contacts the tension roller 53 in the counter direction with respect to the driving rotation direction of the intermediate transfer belt 5, and scrapes off the toner at the nip portion 33 (FIG. 3B). In this way, after the secondary transfer is completed, the transfer residual toner remaining on the intermediate transfer belt 5 is removed and collected from the surface by the intermediate transfer belt cleaning device 11.

  The mounting position of the cleaning blade 28 is set at a set angle θ (angle formed by the tangent to the tension roller 53 at the intersection of the intermediate transfer belt 5 and the cleaning blade rubber portion 29 and the cleaning blade rubber portion 29). Further, the penetration amount δ (the length in the thickness direction in which the cleaning blade rubber portion 29 overlaps the tension roller 53) was 1.5 mm, and the contact pressure of the cleaning blade 28 was 0.6 N / cm. By setting this setting position, it is possible to suppress turning-up and slipping of the cleaning blade in a high-temperature and high-humidity environment (30 ° C./80%). In addition, good cleaning performance can be obtained without causing poor cleaning in a low-temperature and low-humidity environment (15 ° C./10%).

  The cleaning configuration of the present invention is appropriately selected according to the intermediate transfer belt material. Preferably, the hardness of the cleaning blade rubber portion 29 is in the range of 70 to 80 ° according to JIS K6253 standard, and the contact pressure of the cleaning blade 28 is preferably in the range of 0.4 to 0.8 N / cm. . The thickness of the rubber part is preferably 1.5 mm to 2.5 mm. Further, the preferable range of the setting angle θ is 15 ° to 30 °, and the penetration amount δ is preferably 1.0 mm to 2.0 mm.

<Configuration of intermediate transfer belt>
Next, the configuration of the intermediate transfer belt of the present invention will be described.

  The intermediate transfer belt 5 of the present invention is an endless film-like member composed of a base layer and a surface layer. FIG. 3 is an enlarged partial cross-sectional view in the direction orthogonal to the rotational driving direction near the surface layer of the intermediate transfer belt 5. The base layer 101 is a layer having a thickness of 70 μm in which carbon black is dispersed as a resistance adjusting agent in a polyethylene naphthalate resin. The surface layer 102 is made of a layer having a thickness of 3 μm in which antimony-doped zinc oxide 105 is dispersed as a resistance adjusting agent in an acrylic resin 103 and polytetrafluoroethylene (hereinafter referred to as PTFE) particles 104 are added. As shown in FIG. 3 (a), the PTFE particles 104 added to the surface layer 102 are deposited on the outermost surface and form a protrusion shape in a partially exposed state, and are also dispersed in the surface layer. Existing.

The volume resistivity of the intermediate transfer belt 5 is Hiresta UP MCP-HT450 (manufactured by Mitsubishi Chemical Corporation), the temperature is 25 ° C., and the relative humidity is 10 ¹⁰ Ω · cm in a 50% environment. In addition, if the volume resistivity of the intermediate transfer belt 5 is in the range of 10 ⁹ to 10 ¹² Ω · cm, good image formation can be performed.

<Method for producing intermediate transfer belt>
Next, a method for producing the intermediate transfer belt 5 of the present invention will be described.

  First, examples of the material used for the base layer 101 of the intermediate transfer belt 5 of the present invention include polycarbonate, polyvinylidene fluoride (PVDF), polyethylene, polypropylene, polymethylpentene-1, polystyrene, polyamide, polysulfone, polyarylate, and polyethylene. Examples include thermoplastic resins such as terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyphenylene sulfide, polyethersulfone, polyethernitrile, thermoplastic polyimide, polyetheretherketone, thermotropic liquid crystal polymer, and polyamic acid. It is done. Two or more of these can be mixed and used. Further, the base layer 101 of the intermediate transfer belt 5 can be obtained by melt-kneading a conductive material or the like in these thermoplastic resins, and then appropriately selecting a molding method such as inflation molding, cylindrical extrusion molding, or blow molding. .

  Next, a method for manufacturing the surface layer 102 will be described.

  From the viewpoint of increasing the surface hardness of the intermediate transfer belt 5 and improving durability (abrasion resistance), the surface layer 102 that holds the toner transferred from the photosensitive drum 1 is made of thermosetting, ultraviolet rays, electron beams, or the like. A curable material that is cured by irradiation with energy rays is used. In particular, ultraviolet rays having high curability and electron beams are preferable, but not limited thereto.

  Among the curable materials, examples of the organic material include curable resins such as melamine resin, urethane resin, alkyd resin, acrylic resin, and fluorine curable resin. Examples of inorganic materials include alkoxysilane / alkoxyzirconium-based materials and silicate-based materials. Examples of the organic / inorganic hybrid material include inorganic fine particle-dispersed organic polymer materials, inorganic fine particle-dispersed organoalkoxysilane materials, acrylic silicon materials, and organoalkoxysilane materials. Among these, a resin material is preferable among the curable materials from the viewpoint of wear resistance, crack resistance, and the like of the intermediate transfer belt surface layer 102. Among the curable resins, the unsaturated double bond-containing acrylic copolymer is cured. The resulting acrylic resin is preferred. The unsaturated double bond-containing acrylic copolymer is available, for example, as lucifural (trade name, manufactured by Nippon Paint Co., Ltd.), which is an acrylic ultraviolet curable hard coat material.

  Furthermore, a conductive material may be added to the intermediate transfer belt surface layer 102 of the present invention for resistance control. As the conductive material, an electron conductive material or an ion conductive material can be used. Examples of the electronically conductive material include carbon black, PAN-based carbon fibers, and carbon-based conductive fillers in the form of particles, fibers, or flakes such as pulverized expanded graphite. Furthermore, particulate, fibrous, or flaky metallic conductive fillers such as silver, nickel, copper, zinc, aluminum, stainless steel, and iron are also included. Further, particulate metal oxide conductive fillers such as antimony-doped tin oxide, tin-doped indium oxide, and aluminum-doped zinc oxide can be used. Examples of the ion conductive material include an ionic liquid, a conductive oligomer, and a quaternary ammonium salt. One or more of these conductive materials are selected as appropriate, and an electronic conductive material and an ion conductive material may be mixed and used. Among these, a particulate metal oxide conductive filler of submicron or less is preferable in that the addition amount is small and surface smoothness is obtained.

  Further, a solid lubricant may be added to the material for the intermediate transfer belt surface layer 102. Examples of solid lubricants include PTFE resin powder, ethylene trifluoride chloride resin powder, ethylene tetrafluoride hexafluoropropylene resin powder, vinyl fluoride resin powder, vinylidene fluoride resin powder, difluoride difluoride. Fluorine-containing particles such as ethylene chloride resin powder, fluorinated graphite, and copolymers thereof are appropriately selected. Moreover, it is not necessarily limited to these, Solid lubricants, such as a silicone resin particle and a molybdenum disulfide powder, may be sufficient. Among these, emulsion-polymerized PTFE resin particles are preferable because they have a low coefficient of friction on the particle surface and can reduce wear of other members in contact with the surface layer 102 of the intermediate transfer belt.

  Antimony-doped zinc oxide as a conductive material is mixed in the unsaturated double bond-containing acrylic copolymer, and dispersed and mixed with a high-pressure emulsifying disperser to prepare a coating solution for forming a surface layer.

  Examples of a method for forming the surface layer 102 on the base layer 101 include a normal coating method such as dip coating, spray coating, roll coating, spin coating, and the like. By appropriately selecting from these methods, the surface layer 102 having a desired film thickness can be obtained.

<Configuration of process cartridge>
Next, the overall configuration of the process cartridge 7 that is preferably mounted on the image forming apparatus 100 of the present embodiment will be described. In the present embodiment, the configuration and operation of the process cartridge 7 for each color are substantially the same except for the type (color) of the toner contained therein.

  FIG. 4 is a schematic cross-sectional view (main cross-sectional view) of the process cartridge 7 of this embodiment viewed along the longitudinal direction (rotational axis direction) of the photosensitive drum 1. The posture of the process cartridge 7 in FIG. 4 is a posture in a state where the process cartridge 7 is mounted on the image forming apparatus main body. When the positional relationship and direction of each member of the process cartridge are described below, the positional relationship and direction in this posture are described below. Etc.

  The process cartridge 7 is configured by integrating a photosensitive unit 13 including the photosensitive drum 1 and the developing unit 4 including a developing roller 17 and the like.

  The photoconductor unit 13 has a cleaning frame 14 as a frame that supports various elements in the photoconductor unit 13. The photosensitive drum 1 is rotatably attached to the cleaning frame 14 via a bearing (not shown). The photosensitive drum 1 is rotationally driven in the direction of the arrow A (clockwise) in accordance with the image forming operation by transmitting the driving force of a driving motor (not shown) as a driving means (driving source) to the photosensitive unit 13. Is done. In this embodiment, the photosensitive drum 1 which is the center of the image forming process is an organic photosensitive drum in which an outer surface of an aluminum cylinder is coated with a functional undercoat layer, a carrier generation layer, and a carrier transfer layer in this order. 1 is used.

  Further, the cleaning unit 6 and the charging roller 2 are disposed in the photosensitive unit 13 so as to come into contact with the peripheral surface of the photosensitive drum 1. The transfer residual toner removed from the surface of the photosensitive drum 1 by the cleaning member 6 falls and is stored in the cleaning frame 14.

  The charging roller 2 as charging means is driven to rotate by bringing the roller portion of conductive rubber into pressure contact with the photosensitive drum 1.

  Here, as a charging process, a predetermined DC voltage is applied to the core of the charging roller 2 with respect to the photosensitive drum 1, whereby a uniform dark portion potential (Vd) is applied to the surface of the photosensitive drum 1. Is formed. The spot pattern of the laser beam emitted in accordance with the image data by the laser beam from the scanner unit 3 described above exposes the photosensitive drum 1, and the exposed portion is charged on the surface by the carrier from the carrier generation layer. Disappears and the potential drops. As a result, an electrostatic latent image is formed on the photosensitive drum 1 with a predetermined light portion potential (Vl) at an exposed portion and a predetermined dark portion potential (Vd) at an unexposed portion. In this embodiment, Vd = −500V and Vl = −100V.

  On the other hand, the developing unit 4 has a developing roller 17 as a developer carrying member for carrying toner 80 and a developing chamber in which a toner supply roller 20 as a supply member for supplying toner to the developing roller 17 is disposed. doing. Further, the developing unit 4 includes a toner storage chamber 18 that stores toner.

  The toner supply roller 20 is rotated by forming a toner nip N (a portion where the toner is sandwiched between the development roller 17 and the toner supply roller 20) between the toner supply roller 20 and the development roller 17.

  A stirring and conveying member 22 is provided in the toner storage chamber 18. The agitating / conveying member 22 agitates the toner accommodated in the toner accommodating chamber 18 and also conveys the toner toward the upper portion of the toner supply roller 20 in the direction of arrow G in the figure. In this embodiment, the agitating and conveying member is driven to rotate at 30 rpm.

  The developing blade 21 is disposed below the developing roller 17 and is in contact with the developing roller at a counter, and regulates the coating amount of the toner supplied by the toner supply roller 20 and applies a charge. In the present embodiment, a SUS thin plate having a thickness of 0.1 mm is used as the developing blade 21 and a contact pressure is formed by utilizing the spring elasticity of the thin plate. Abut. Here, the developing blade is not limited to this, and may be a thin metal plate such as phosphor bronze or aluminum. Alternatively, the surface of the developing blade 21 may be coated with a thin film such as polyamide elastomer, urethane rubber, or urethane resin.

  The toner is triboelectrically charged by rubbing between the developing blade 21 and the developing roller 17 to be charged, and at the same time the layer thickness is regulated. In this embodiment, a predetermined voltage is applied to the developing blade 21 from a blade bias power source (not shown) to stabilize the toner coat. In this example, V = −500 V was applied as the blade bias.

  The developing roller 17 and the photosensitive drum 1 rotate so that the surfaces of the developing roller 17 and the photosensitive drum 1 move in the same direction (in this embodiment, from the bottom to the top).

  In the present embodiment, the developing roller 17 is disposed in contact with the photosensitive drum 1, but the developing roller 17 is disposed close to the photosensitive drum 1 at a predetermined interval. May be.

  In this embodiment, a toner charged negatively by frictional charging with respect to a predetermined DC bias applied to the developing roller 17 has a bright portion potential portion in a developing portion where the toner contacts the photosensitive drum 1 from the potential difference. The electrostatic latent image is visualized by transferring only to. In this embodiment, by applying V = −300 V to the developing roller, a potential difference ΔV = 200 V from the bright portion is formed, and a toner image is formed.

  The surfaces of the toner supply roller 20 and the development roller 17 rotate in the same direction at the nip portion N (in this embodiment, the toner supply roller 20 is in the direction of the arrow E (clockwise), and the development roller 17 is It is rotating in the direction of arrow D).

  This reduces the load on the toner in the nip portion N compared to when rotating in the reverse direction, and it is possible to suppress toner deterioration.

  As the toner used in the process cartridge preferably used in the present invention, securing fluidity is more important.

  Although the configuration in which the developing roller and the toner supply roller rotate in the same direction in the nip portion is certainly in the direction of suppressing toner deterioration, the toner supply roller, which is another role of the toner supply roller, is poorly peelable. Is the direction. For this reason, the toner that has not contributed to the development is likely to be carried around to the developing roller, a difference in charge amount from the portion that has contributed to the development is generated, and a ghost image is likely to be generated. It is considered that improving the fluidity of the toner improves the rising of the charging of the toner on the developing roller and suppresses the charge amount difference. Further, it is believed that improving the fluidity of the toner leads to an increase in the movement of the toner in the nip portion between the developing roller and the toner supply roller, thereby suppressing the charge amount difference.

As described above, as a method for ensuring the fluidity of the toner,
(1) The amount of silica fine particles added to the toner particles is controlled.
(2) Control by the particle size of the silica fine particles added to the toner particles.
(3) The type is controlled by the type, amount, and method of the surface treatment agent for silica fine particles.
(4) In addition to silica fine particles, other inorganic fine powders such as titanium and alumina are used in combination.
(5) Control is performed by a combination of the type of release agent used for the toner particles and the type of silica fine particles added to the toner particles.
The method etc. are mentioned.

  The toner supply roller 20 is an elastic sponge roller in which a foam layer is formed on the outer periphery of a conductive metal core. The toner supply roller 20 and the developing roller 17 are in contact with each other with a predetermined amount of penetration, that is, in FIG. The toner supply roller 20 and the developing roller 17 rotate with a peripheral speed difference in the same direction at the nip portion N. With this operation, the toner is supplied to the developing roller 17 by the toner supply roller 20. . At this time, the toner supply amount to the developing roller can be adjusted by adjusting the potential difference between the toner supply roller and the developing roller. In this embodiment, the toner supply roller is driven to rotate at 200 rpm and the developing roller is driven to rotate at 100 rpm, and a DC bias is applied to the toner supplying roller so as to have the same potential as the developing roller.

  In this embodiment, both the developing roller 17 and the toner supply roller 20 have an outer diameter of 15 mm, and the amount of toner supply roller 20 entering the developing roller 17, that is, the toner supply roller 20 is recessed by the developing roller 17. The dent amount ΔE is set to 1.0 mm. Further, the toner supply roller and the developing roller are arranged so that the center height is the same.

  Details of the toner supply roller used in this embodiment will be described below.

  The toner supply roller 20 in this embodiment includes a conductive support and a foam layer supported by the conductive support. Specifically, a foamed urethane layer as a foamed layer composed of a cored bar electrode 20a having an outer diameter of φ5 (mm), which is a conductive support, and an open cell body (open cells) in which bubbles are connected to the periphery thereof. 20b is provided and rotates in the direction E in the figure.

A large amount of toner can enter the inside of the toner supply roller 20 by using urethane on the surface layer as an open cell body. Further, the resistance of the toner supply roller 20 in this embodiment is 1 × 10 ⁹ (Ω).

  Here, a method of measuring the resistance of the toner supply roller 20 will be described. The toner supply roller 20 is brought into contact with an aluminum sleeve having a diameter of 30 mm so that an intrusion amount described later becomes 1.5 mm. By rotating the aluminum sleeve, the supply roller 2 is driven to rotate relative to the aluminum sleeve at 30 rpm.

  Next, a DC voltage of −50 V is applied to the developing roller 17. At that time, a resistance of 10 kΩ is provided on the ground side, the current is calculated by measuring the voltage at both ends, and the resistance of the toner supply roller 20 is calculated. In this embodiment, the surface cell diameter of the toner supply roller 20 is set to 50 μm to 1000 μm.

  Here, the cell diameter means the average diameter of the foamed cells having an arbitrary cross section. First, the area of the foamed cell that is the maximum is measured from the enlarged image of the arbitrary cross section, and the maximum cell diameter is converted from this area by converting the equivalent circle diameter. Get. And after deleting the foam cell which is 1/2 or less of this maximum cell diameter as noise, it points out the average value of each cell diameter converted similarly from the remaining individual cell area.

  Next, the flow of toner in the developing chamber will be described with reference to FIGS.

  In this embodiment, FIG. 5 is an enlarged schematic cross-sectional view of the developing chamber, and shows the movement of the toner conveyed from the agitating and conveying member 22 to the toner supply roller 20.

  The toner is supplied to the developing chamber by the agitating / conveying member 22 mainly toward the upper portion of the toner supply roller 20 (arrow G in FIG. 5), and the supplied toner is applied to the inside of the toner supply roller and the surface thereof. Retained. Since the toner supply roller 20 rotates in the direction of arrow E, the toner held on the toner supply roller is conveyed toward the nip portion N with the developing roller (arrow F1 in FIG. 5). Here, a part of the toner conveyed by the toner supply roller is discharged by deformation of the toner supply roller at the entrance to the nip portion N, and is accumulated and stored above the nip portion N (arrow in FIG. 5). F2). In this way, by storing the toner above the nip portion N, the decrease in the toner amount in the supply roller is suppressed between the time when the agitating and conveying member 22 conveys the toner to the developing chamber and the next time it is conveyed. it can. As a result, the stored toner can be stably supplied to the toner supply roller and the developing roller.

  Next, the toner transported to the nip portion N is charged by being rubbed and charged in the nip because the toner supply roller and the developing roller are rotated with a difference in peripheral speed. Thereafter, a part of the charged toner is transferred to the developing roller. In this embodiment, since the peripheral speed of the toner supply roller is faster than the peripheral speed of the developing roller, the amount of toner passing over the developing roller per unit time increases, and more toner is transferred to the developing roller. It will be. The toner transferred to the developing roller is regulated and charged by the developing blade at a regulating portion between the developing roller and the developing blade, and a uniform toner coat is formed on the developing roller by the toner passing through the regulating portion.

  On the other hand, the toner regulated by the developing blade is conveyed toward the developing opening (opening portion) provided in the developing chamber by the rotation of the toner supply roller, and is returned to the toner containing chamber through the developing opening.

<Fixer configuration>
FIG. 6 shows an apparatus for fixing a toner image by heating a heat-resistant film using a heating element. FIG. 6 shows a fixing device having a structure in which no tension is applied to the heat resistant film (tension-free type). In the present invention, the heating element has a small heat capacity and has a linear or planar heating section, and the maximum temperature of the heating section is preferably 100 ° C. or more and 300 ° C. or less.

  The heat-resistant film is preferably a heat-resistant sheet having a thickness of 1 μm or more and 100 μm or less. As these heat-resistant sheets, polyester, PET (polyethylene terephthalate), PFA (tetrafluoroethylene-par In addition to polymer sheets such as fluoroalkyl vinyl ether copolymer), PTFE (polytetrafluoroethylene), polyimide, and polyamide, metal sheets such as aluminum, and laminate sheets composed of metal sheets and polymer sheets are used.

Reference numeral 64 denotes a low heat capacity linear heating element fixedly supported by the apparatus, and includes a heater substrate 64a, an energization heating resistor (heating element) 64b, a surface protection layer 64c, a temperature detecting element 64d, and the like. The heater substrate 64a is a member having heat resistance, insulation, low heat capacity, and high heat conductivity, and is, for example, an alumina substrate having a thickness of 1 mm, a width of 10 mm, and a length of 240 mm. The heating element 64b is coated with an electric resistance material in a linear or narrow strip shape having a thickness of about 10 μm and a width of 1 to 3 mm along the longitudinal center of the lower surface of the heater substrate 64a (the side facing the heat resistant film 65). doing. And about 10 micrometers of heat-resistant glass is coated as a surface protective layer 64c on it. As the electrical resistance material, for example, Ag / Pd (silver palladium), Ta ₂ N, RuO ₂ or the like is used. Moreover, as a coating method of the electrical resistance material, a screen printing method or the like is used. The temperature measuring element 64d is, for example, a low-temperature-capacitance resistance measuring resistor such as a Pt film that is applied by screen printing or the like on the substantially central portion of the upper surface of the heater substrate 64a (the side opposite to the surface on which the heating element 64b is provided). Is the body. A thermistor with a low heat capacity can also be used.

  In the case of the heating element 64 of this example, the heating element 64b having a linear or planar shape is energized at a predetermined timing by an image formation start signal to cause the heating element 64b to generate heat over substantially the entire length. The energization is AC 100 V, and the supplied power is controlled by controlling the phase angle of energization by an energization control circuit (not shown) including a triac according to the temperature detected by the temperature sensing element 64d.

  Since the heating element 64 has a small heat capacity of the heater substrate 64a, the heating element 64b, and the surface protective layer 64c by energizing the heating element 64b, the surface of the heating element is rapidly heated to a required fixing temperature (for example, 140 ° C. to 200 ° C.). To rise. The heat resistant film 65 is in contact with the heating body 64.

  In order to reduce the heat capacity and improve the quick start performance, the heat resistant film 65 is made of a single layer or composite layer film having a total thickness of 100 μm or less and 20 μm or more, which has heat resistance, releasability, strength and durability. Can be used. For example, polyimide, polyetherimide (PEI), polyethersulfone (PES), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (PFA), polyetheretherketone (PEEK), polyparabanic acid (PPA), Alternatively, a composite layer film such as a 20 μm-thick polyimide film on at least the image contact surface side is made of PTFE (tetrafluoroethylene resin), fluororesin such as PAF / FEP, silicone resin, etc., and further conductive material (carbon black, graphite, And a releasable coat layer to which conductive whiskers and the like are added is applied to a thickness of 10 μm.

  The support roller 62, which is a rotating body, is made of a rubber elastic body having good releasability, such as silicon rubber, and is pressed against the heating body 64 via a heat resistant film 65 to form a nip portion, and the heat resistant film 65 is fixed to the predetermined length. Drive moving to speed. When a recording material sheet as a material to be heated is introduced between the heat resistant film 65 and the recording material sheet, the recording material sheet is brought into close contact with the surface of the heat resistant film 65 and pressed against the heating body 64, and is moved and driven together with the heat resistant film 65. Let

  In the above-described embodiment, the printer is exemplified as the image forming apparatus, but the present invention is not limited to this. For example, the present invention is also effective in other image forming apparatuses such as a copying machine, a facsimile machine, or a multifunction machine that combines these functions. The same effect can be obtained even in an image forming apparatus that uses a recording material carrier and sequentially superimposes and transfers the toner images of the respective colors on the recording material carried on the recording material carrier.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to the examples. In addition, all "parts" described in the examples indicate parts by mass.

(Production example of silica fine particles (A-1))
As the silica raw material fine particles, those having an average primary particle size of 7.0 nm and a BET specific surface area of 380 m ² / g were used. As a primary treatment agent, a solution in which 10.0 parts of hexamethyldisilazane was dissolved in 10,000 parts of hexane was sprayed on 100 parts of silica base particles. The reaction was carried out at 200 ° C. with sufficient stirring so that particle coalescence did not occur. Next, as a secondary treating agent, a solution in which 15.0 parts of dimethyl silicone oil (viscosity = 100 mm ² / s) was dissolved in 10,000 parts of hexane was sprayed on 100 parts of silica base particles. Heating treatment was performed at 270 ° C. for 2 hours with sufficient stirring so that the coalescence of particles did not occur, and silica fine particles A-1 were obtained. Table 1 shows the physical properties of the obtained silica fine particles A-1.

(Production example of silica fine particles (A-2))
The primary treatment agent was changed to 10.0 parts isobutyltrimethoxysilane. In addition, the secondary treatment agent was changed to 15.0 parts of methylphenyl silicone oil (viscosity = 100 mm ² / s). Other than that was carried out similarly to the manufacture example of silica fine particle (A-1), and obtained silica fine particle A-2. Table 1 shows the physical properties of the obtained silica fine particles A-2.

(Production example of silica fine particles (A-3))
The silica fine particles (A-1) were changed to 45.0 parts dimethylsilicone oil (viscosity = 1000 mm ² / s) as the primary treatment agent, except that the heat treatment was performed at 150 ° C. for 2 hours and the secondary treatment was not performed. ) To obtain silica fine particles A-3. Table 1 shows the physical properties of the obtained silica fine particles A-3.

(Production example of silica fine particles (A-4))
The silica fine particles (A-1) except that 30.0 parts of dimethyl silicone oil (viscosity = 100 mm ² / s) was changed as a primary treatment agent, heat treatment was performed at 150 ° C. for 2 hours, and no secondary treatment was performed. ) To obtain silica fine particles A-4. Table 1 shows the physical properties of the obtained silica fine particles A-4.

(Production example of silica fine particles (A-5))
As the silica raw material fine particles, those having an average primary particle size = 5.0 nm and a BET specific surface area of 410 m ² / g were used. Further, silica fine particles A-5 are obtained in the same manner as in the production example of the silica fine particles (A-1) except that the secondary treatment agent is changed to 17.0 parts of dimethyl silicone oil (viscosity = 100 mm ² / s). It was. Table 1 shows the physical properties of the obtained silica fine particles A-5.

(Production example of silica fine particles (A-6))
As the silica raw material fine particles, those having an average primary particle size = 9.8 nm and a BET specific surface area of 250 m ² / g were used. Further, silica fine particles A-6 were obtained in the same manner as in the production example of silica fine particles (A-1) except that the secondary treatment agent was changed to 12.0 parts of dimethyl silicone oil (viscosity = 100 mm ² / s). It was. Table 1 shows the physical properties of the obtained silica fine particles A-6.

(Production example of silica fine particles (A-7))
As the silica original fine particles, those having an average primary particle size = 12.1 nm and a BET specific surface area of 200 m ² / g were used. Further, silica fine particles A-7 are obtained in the same manner as in the production example of the silica fine particles (A-1) except that the secondary treatment agent is changed to 10.0 parts of dimethyl silicone oil (viscosity = 100 mm ² / s). It was. Table 1 shows the physical properties of the obtained silica fine particles A-7.

(Production example of silica fine particles (A-8))
As the silica original fine particles, those having an average primary particle size = 15.9 nm and a BET specific surface area of 130 m ² / g were used. Further, silica fine particles A-8 are obtained in the same manner as in the production example of the silica fine particles (A-1) except that the secondary treatment agent is changed to 8.0 parts of dimethyl silicone oil (viscosity = 100 mm ² / s). It was. Table 1 shows the physical properties of the obtained silica fine particles A-8.

(Production example of silica fine particles (B-1))
As the silica raw material fine particles, those having an average primary particle size of 7.0 nm and a BET specific surface area of 380 m ² / g were used. A solution in which 30.0 parts of dimethyl silicone oil (viscosity = 100 mm ² / s) is dissolved in 10,000 parts of hexane with respect to 100 parts of silica raw material fine particles as a primary treating agent with respect to 100 parts of silica raw material fine particles. Sprayed. The mixture was heat-treated at 250 ° C. for 2 hours with sufficient stirring so that the particles were not coalesced. Next, a solution obtained by dissolving 30.0 parts of hexamethyldisilazane in 10,000 parts of hexane was sprayed as a secondary treatment agent. The mixture was allowed to react at 200 ° C. with sufficient stirring so as not to cause coalescence of particles to obtain silica fine particles B-1. Table 1 shows the physical properties of the obtained silica fine particles B-1.

(Production example of silica fine particles (B-2))
The primary treatment agent was changed to 30.0 parts of methylphenyl silicone oil (viscosity = 100 mm ² / s). Moreover, it changed into 10.0 parts isobutyltrimethoxysilane as a secondary processing agent. Other than that was carried out similarly to the manufacture example of silica fine particle (B-1), and obtained silica fine particle B-2. Table 1 shows the physical properties of the obtained silica fine particles B-2.

(Production example of silica fine particles (B-3))
The silica was treated in the same manner as in the production example of the silica fine particles (B-1) except that 30.0 parts of dimethyl silicone oil (viscosity = 100 mm ² / s) was changed as the primary treatment agent and the secondary treatment was not performed. Fine particles B-3 were obtained. Table 1 shows the physical properties of the obtained silica fine particles B-3.

(Production example of silica fine particles (B-4))
The silica was treated in the same manner as in the production example of silica fine particles (B-1) except that the primary treatment agent was changed to 45.0 parts of dimethyl silicone oil (viscosity = 100 mm ² / s) and the secondary treatment was not performed. Fine particles B-4 were obtained. Table 1 shows the physical properties of the obtained silica fine particles B-4.

(Production example of silica fine particles (B-5))
As the silica raw material fine particles, those having an average primary particle size = 5.0 nm and a BET specific surface area of 410 m ² / g were used. Further, silica fine particles B-5 were obtained in the same manner as in the production example of silica fine particles (B-1) except that the primary treatment agent was changed to 33.0 parts of dimethyl silicone oil (viscosity = 100 mm ² / s). . Table 1 shows the physical properties of the obtained silica fine particles B-5.

(Production example of silica fine particles (B-6))
As the silica raw material fine particles, those having an average primary particle size = 9.8 nm and a BET specific surface area of 250 m ² / g were used. Further, silica fine particles B-6 were obtained in the same manner as in the production example of silica fine particles (B-1) except that the primary treatment agent was changed to 25.0 parts of dimethyl silicone oil (viscosity = 100 mm ² / s). . Table 1 shows the physical properties of the obtained silica fine particle B-6.

(Production example of silica fine particles (B-7))
As the silica original fine particles, those having an average primary particle size = 12.1 nm and a BET specific surface area of 200 m ² / g were used. Further, silica fine particles B-7 were obtained in the same manner as in the production example of silica fine particles (B-1) except that the primary treatment agent was changed to 20.0 parts of dimethyl silicone oil (viscosity = 100 mm ² / s). . Table 1 shows the physical properties of the obtained silica fine particle B-7.

(Production example of silica fine particles (B-8))
As the silica original fine particles, those having an average primary particle size = 15.9 nm and a BET specific surface area of 130 m ² / g were used. Further, silica fine particles B-8 were obtained in the same manner as in the production example of the silica fine particles (B-1) except that the primary treatment agent was changed to 12.0 parts of dimethyl silicone oil (viscosity = 100 mm ² / s). . Table 1 shows the physical properties of the obtained silica fine particles B-8.

(Production example of silica fine particles (B-9))
Silica fine particles B-9 were obtained in the same manner as in the production example of the silica fine particles (B-1) except that the primary treatment agent was changed to 10.0 parts of dimethyl silicone oil (viscosity = 100 mm ² / s). Table 1 shows the physical properties of the obtained silica fine particles B-9.

(Production example of silica fine particles (B-10))
Except for changing to 10.0 parts of dimethyl silicone oil (viscosity = 100 mm ² / s) as a primary treatment agent and performing heat treatment at 300 ° C. for 2 hours, in the same manner as in the production example of silica fine particles (B-1), Silica fine particles B-10 were obtained. Table 1 shows the physical properties of the obtained silica fine particle B-10.

(Production example of black toner (Bk-1))
(Preparation of aqueous dispersion medium)
・ Water: 350.00 parts ・ Trisodium phosphate: 15.00 parts While stirring the above mixture at a speed of 12,000 rpm with a high-speed agitator TK-type homomixer, the mixture was heated to 60 ° C. Retained. Next, 9 parts of calcium chloride was added to prepare an aqueous dispersion medium containing a fine hardly water-soluble stabilizer Ca ₃ (PO ₄ ) ₂ .

(Preparation of polymerizable monomer composition 1: dispersion step)
-Styrene ... 30.00 parts-Carbon black ... 8.00 parts (DBP oil absorption 42.2 (ml / 100g), pH 9.0)
・ Negative charge control agent 1.00 parts (aluminium compound of 3,5-di-tertiary butylsalicylic acid)
The above mixture was dispersed with an attritor at room temperature for 5 hours to obtain a polymerizable monomer mixture 1. Subsequently, the monomer mixture 1 was put into a stirring tank capable of adjusting the temperature, and the temperature was raised to 60 ° C. Then
Wax (myristyl stearate): 15.00 parts of the above are put into the stirring tank, and
Divinylbenzene: 0.20 part was added, and stirring was continued for 1 hour to prepare a polymerizable monomer composition 1.

(Preparation of polymerizable monomer composition 2: dissolution step)
· Styrene · · · 40.00 parts · n-butyl acrylate · · · 30.00 parts · Polar resin A1 · · · 25.00 parts (styrene-methacrylic acid-methyl methacrylate-2- Hydroxyethyl methacrylate copolymer, Mw = 15200, Tg = 90 ° C., acid value Av = 25 mgKOH / g, hydroxyl value OHv = 8 mgKOH / g)
Polar resin B1 5.00 parts (polyester resin which is a polycondensate of propylene oxide modified bisphenol A and terephthalic acid, Mw = 9500, Tg = 74 ° C., acid value Av = 9 mgKOH / g, hydroxyl group Value OHv = 25 mg KOH / g)
Polar resin C1 2.00 parts (styrene-2-ethylhexyl acrylate copolymer containing 10% 2-acrylamido-2-methylpropanesulfonic acid, Mp = 18000)
The above mixture was charged into a temperature-adjustable stirring tank, and the formulation was charged into a temperature-controllable stirring tank, and the temperature was raised to 60 ° C. After raising the temperature to 60 ° C., the mixture was stirred for 5 hours.

(Adjustment process)
The temperature of the polymerizable monomer composition 2 was raised to 70 ° C., and the polymerizable monomer composition 1 was added thereto, followed by stirring for 10 minutes. Thereafter, the temperature was slowly lowered to 65 ° C.

(Granulation / polymerization process)
The obtained mixture of the polymerizable monomer compositions 1 and 2 was put into the aqueous dispersion medium. Furthermore, 8.00 parts of 2,2′-azobis-isobutyrovaleronitrile as a polymerization initiator was added to the aqueous medium dispersion, and granulated for 20 minutes while maintaining the rotation speed of the stirrer at 12000 rpm. Thereafter, the high-speed stirrer was transferred to a propeller-type stirrer, the internal temperature was raised to 70 ° C., and the reaction was allowed to proceed for 5 hours with slow stirring. Next, the temperature inside the container was raised to 80 ° C. and maintained for 5 hours. Thereafter, the mixture was cooled to obtain a polymer fine particle dispersion.

(Washing / Solid-liquid separation / Drying process / External addition process)
Diluted hydrochloric acid was added to the obtained polymer fine particle dispersion to adjust the pH to 1.4, and the stabilizer Ca ₃ (PO ₄ ) ₂ was dissolved. Further, after filtration and washing, the resultant was vacuum-dried at a temperature of 40 ° C., coarse particles were removed using a sieve having an opening of 150 μm, and the particle diameter was adjusted to obtain black toner particles. To 100.00 parts of the obtained black toner particles, 2.00 parts of silica fine particles (A-1) were externally added by stirring for 10 minutes with a Henschel mixer to obtain black toner (Bk-1). . Table 3 shows the physical properties of the toner.

(Production example of yellow toner (Y-1))
In the production example of black toner (Bk-1), 8.00 parts of carbon black was added to C.I. I Pigment Yellow 155 was changed to 6.00 parts. Further, a yellow toner is produced in the same manner as in the black toner (Bk-1) production example except that 2.00 parts of silica fine particles (A-1) are changed to 2.00 parts of silica fine particles (B-1). (Y-1) was produced. Table 3 shows the physical properties of the toner.

(Production example of magenta toner (M-1))
In the production example of black toner (Bk-1), 8.00 parts of carbon black was added to C.I. Magenta toner (M-1) was produced in the same manner as in the production example of black toner (Bk-1) except that I Pigment Red 122 was changed to 8.00 parts. Table 3 shows the physical properties of the toner.

(Production example of cyan toner (C-1))
In the production example of black toner (Bk-1), 8.00 parts of carbon black was added to C.I. I Pigment Blue 15: 3 was changed to 7.00 parts. Moreover, 2.00 parts of silica fine particles (A-1) were changed to 2.00 parts of silica fine particles (B-1). Except for the above changes, cyan toner (C-1) was produced in the same manner as in the production example of black toner (Bk-1). Table 3 shows the physical properties of the toner.

(Example of intermediate transfer belt production)
<Preparation of base layer>
A method for producing the base layer 101 of the intermediate transfer belt in FIGS. 1 and 4 will be described. A bottle-shaped molded body was obtained by blow-molding a polyethylene naphthalate resin, and an endless belt body was obtained by cutting this with an ultrasonic cutter. In the polyethylene naphthalate resin, carbon black is dispersed as a resistance adjusting agent. The polyethylene naphthalate resin belt having a thickness of 70 μm thus obtained was used as the base layer 101 of the intermediate transfer belt 5.

<Preparation of surface layer forming coating solution (ultraviolet curable resin composition)>
Lucifal (trade name, manufactured by Nippon Paint Co., Ltd.), which is an acrylic ultraviolet curable hard coat material containing pentaerythritol triacrylate and pentaerythritol tetraacrylate, was put into a container shielded from ultraviolet rays. Subsequently, PTFE particles having a particle size of 200 nm were added as slidability imparting particles. Next, a high molecular weight fluorine-based graft polymer GF400 (trade name, manufactured by Toagosei Co., Ltd.) and methyl isobutyl ketone are added as a dispersant for PTFE particles, and the mixture is treated with a high-speed shearing disperser (homogenizer). Dispersion was performed.

  Thereafter, the liquid subjected to the above-described rough dispersion treatment was subjected to the main dispersion treatment using a high-pressure emulsification disperser (Nanobeta: manufactured by Yoshida Kikai Kogyo Co., Ltd.). Further, the liquid after completion of the PTFE dispersion treatment was added dropwise to SELNAX (trade name, 210IP: manufactured by Nissan Chemical Industries, Ltd.) as conductive particles while stirring a liquid in which an amine having a low molecular weight was added as a dispersant. Thus, a coating solution for forming the surface layer was obtained.

<Preparation of intermediate transfer belt with surface layer>
On the base layer 101 for the intermediate transfer belt, the ultraviolet curable resin composition was dip-coated in a coating environment of 25 ° C. and a relative humidity of 60%. Then, ultraviolet rays are irradiated using an ultraviolet irradiation device (trade name: UE06 / 81-3, manufactured by Eyegraphic Co., Ltd., integrated light quantity: 1000 mJ / cm ² ) in the same place as the coating environment 10 seconds after the coating is completed. Was applied to cure the surface layer 102. As a result, a cured resin film having a thickness of 3 μm was formed, and this cured resin film was used as the intermediate transfer belt surface layer 102. Thus, the intermediate transfer belt 5 having the surface layer 102 was produced.

  The following [1] to [8] were evaluated for the black toner (Bk-1), yellow toner (Y-1), magenta toner (M-1), and cyan toner (C-1). The evaluation results are shown in Table 5. As an image forming apparatus for image evaluation, a remodeling machine of LBP-9500C (manufactured by Canon), which is a commercially available laser printer as shown in FIG. 1, was used. The remodeling points of this evaluation machine are as follows. Also, during full-color image formation, UCR control is performed in which the overlap of yellow, magenta, and cyan is replaced with black and the color toner is reduced by that amount.

  (1) The process speed was set to 210 mm / sec by changing the gear and software of the evaluation machine main body.

  (2) As a cartridge used for evaluation, the product toner was extracted from each commercially available color cartridge in FIG. 1, and the inside was cleaned by air blow. 4 and 5, the developing roller and the toner supply roller rotate in the same direction at the nip portion.

  Evaluation was performed by filling 280 g of black toner (Bk-1), yellow toner (Y-1), magenta toner (M-1), and cyan toner (C-1) in the modified cartridges corresponding to the respective colors.

  (3) The aforementioned acrylic resin coated belt was used as the intermediate transfer belt.

  (4) The software of the fixing device was changed so that the heating temperature could be controlled at 200 ° C. ± 30 ° C.

Black toner (Bk-1), yellow toner (Y-1), magenta toner (M-1), and cyan toner (C-1) are placed in a polycup and controlled to a constant temperature and humidity at 40 ° C./90% humidity. The mixture was left in the constant temperature and humidity layer for 30 days. Thereafter, each toner was packed in a process cartridge and left for 24 hours in a high temperature and high humidity environment (30.0 ° C., 80% RH). Next, using A4 CS-680 (basis weight 68 g / cm ² ) as a transfer material and outputting a full-color image in which the printing rate of each color is adjusted to 3.0%, the image evaluation of 10,000 sheets Went.

  Under high-temperature and high-humidity environment (30.0 ° C, 80% RH), after the image evaluation of 10000 sheets, the following evaluation items [1] to [7] are performed to obtain solid density uniformity, fogging, and blistering Evaluation was made with respect to pressure roller contamination, toner scattering, ghost, and development streaks.

[1] Solid whole area (solid black) image density uniformity A4 CS-680 (basis weight 68 g / cm ² ) was used as a transfer material, and three single-color solid whole area images were continuously output for each color toner. On the first and third images, the average density (measured with a Macbeth reflection densitometer) was measured according to the following procedure. The change rate (%) of the average density of the third sheet relative to the average density of the first sheet was calculated, and the stability of the solid image density was evaluated.

  The average density was obtained by dividing the obtained solid whole area image into nine areas and calculating the average density of the image density at the approximate center of each area. The image density was measured by using “Macbeth reflection densitometer RD918” (manufactured by Macbeth Co.) according to the attached instruction manual for the relative density with respect to the image of the white background portion where the document density was 0.00.

The criteria are shown below.
A: Less than 3% B: 3% or more and less than 5% C: 5% or more and less than 10% D: 10% or more

[2] Image fog In glossy paper mode (1/2 speed), Letter size HP Brochure Paper 200g, Glossy (basis weight 200g / cm ² ) is used as a transfer material, and a solid white image with a printing rate of 0% is printed. Out. Using “REFLECTMETER MODEL TC-6DS” (manufactured by Tokyo Denshoku Co., Ltd.), the fog density (%) is calculated from the difference between the whiteness of the white portion of the measured printout image and the whiteness of the transfer paper, and the image fogging is calculated. Evaluated. Filters were measured for each of green, blue, and amber filters.
A: Less than 0.5% B: 0.5% or more and less than 1.0% C: 1.0% or more and less than 1.5% D: 1.5% or more

[3] Firing Using A4 CS-680 (basis weight 68 g / cm ² ) as a transfer material, secondary color solid images of red, green and blue were output, and the occurrence of blistering of each color was evaluated. Swelling is a phenomenon in which a part of an image is peeled off by a fixing roller during a fixing process because a sufficient amount of heat is not applied to toner particles, and is an index of low-temperature fixability. This level of blistering was evaluated visually. The criteria are shown below.
A: Not generated B: Generated slightly C: Generated but no problem Level D: Remarkably generated

[4] Stain of pressure roller The appearance of residual toner adhering to the pressure roller of the fixing device and the influence on the printout image were visually evaluated. The pressure roller contamination is a phenomenon in which the toner offset to the heating film contaminates the heating roller side between papers, and serves as an index of fixing offset. The criteria are shown below.
A: No toner sticking occurred B: Toner sticking to the edge was observed, but no effect on the fixed image was observed.
C: Although slight toner smearing occurs on the back surface of the printout image due to the toner adhering to the edge, there is almost no effect on the fixed image. D: The toner image has an influence on the fixed image.

[5] Contamination of main body and cartridge due to toner scattering In order to evaluate the balance between chargeability and fluidity of the toner, the degree of contamination by toner around the cartridge and the cartridge in the main body was observed. The criteria are shown below.
A: No contamination by toner around the cartridge and the cartridge in the main body is observed.
B: Contamination due to a small amount of toner is observed on the cartridge.
C: Stain due to toner around the cartridge and the cartridge in the main body is observed, but does not affect the attachment / detachment of the image / cartridge.
D: The periphery of the cartridge and the cartridge in the main body is extremely stained with toner, and there is an adverse effect on the attachment / detachment of the image / cartridge.

[6] Circumferential streak (development streak)
The developing container was disassembled, and the surface and end of each color toner carrier were visually observed. The criteria are shown below.
A: There is no streak in the circumferential direction due to the foreign matter sandwiched between the toner regulating member and the toner carrying member due to toner destruction or fusion at the surface or end of the toner carrying member.
B: Some foreign matter is caught between the toner carrier and the toner end seal.
C: 1-4 streaks in the circumferential direction can be seen at the ends.
D: Five or more streaks in the circumferential direction are observed in the entire region.

[7] Ghost After the evaluation from [1] to [6], each process cartridge was left in a low temperature and low humidity environment (15.0 ° C., 10% RH) for 24 hours. A4 CS-680 (basis weight 68 g / cm ² ) was used as a transfer material, and after printing out a solid white image with a 0% printing ratio of a single color for each color toner, a single-color ghost determination image was output. . The ghost determination image is a 15 mm × 15 mm solid image arranged in a horizontal row at 15 mm intervals at a position 5 mm from the upper end of the transfer paper 1, and the bottom of the solid image is a half with a toner loading of 0.20 mg / cm ² . It is a tone image. A density difference caused by a solid image of 15 mm × 15 mm in the halftone portion of the image was visually determined based on the following criteria.
A: No difference in shading is observed.
B: The difference in light and shade is very slight. There is no problem in actual use.
C: A slight difference in shading is recognized. There is almost no problem in practical use.
D: Difference in shading is recognized. Thereafter, when a full color image is output, a difference from the original image is recognized.

Each toner of black toner (Bk-1), yellow toner (Y-1), magenta toner (M-1), and cyan toner (C-1) is packed in a process cartridge, and is at room temperature and humidity (23 ° C./50). % RH) for 24 hours. Next, using A4 CS-680 (basis weight 68 g / cm ² ) as a transfer material, and outputting a full-color image in which the printing rate of each color is adjusted to 3.0%, 100K image output evaluation Went. At this time, image printing was performed while replacing the cartridge as needed according to the life of each cartridge.

  Then, item [8] was performed and the ITB cleaning property was evaluated.

[8] ITB Cleaning Property A4 CS-680 (basis weight 68 g / cm ² ) was used as a transfer material, and one red image was output without applying a secondary transfer current. Next, after returning the secondary transfer current to an appropriate value, ten 0% printed (solid white) images were output continuously. The obtained image was visually confirmed to evaluate cleaning properties. The criteria are shown below.
A: All 10 sheets show good cleaning properties.
B: Slightly inferior cleaning property is observed on the eighth sheet.
C: A slightly inferior cleaning property is observed on the fifth sheet.
D: A sheet having poor cleaning properties is recognized on the first sheet.

<Examples 2 to 18, Comparative Example 1 and Comparative Example 2>
A black toner (Bk-2 to Bk-12), a yellow toner (Y-2 to Y-10), and a magenta toner (M) are the same as in Example 1 except that the materials described in Tables 3 and 4 are used. -2 to M-8) and cyan toners (C-2 to C-14) were prepared. Thereafter, evaluation was performed in the same manner as in Example 1 using the toner described in Table 5. The evaluation results are shown in Table 5.

<Example 19>
A black toner (Bk-3), a yellow toner (Y-3), a magenta toner (M-3), and a cyan toner (C) are the same as in Example 1 except that the materials described in Tables 3 and 4 are used. -3) was adjusted. In the evaluation, a modified machine of LBP-9500C (manufactured by Canon) was used. The remodeling points of this evaluation machine are as follows. For the toner, the product toner was extracted from a commercially available process cartridge, the interior was cleaned by air blow, and 280 g of each color toner cartridge was filled for evaluation. At the time of full-color image formation, UCR control is performed in which the overlap of yellow, magenta, and cyan is replaced with black and the color toner is reduced by that amount.

  (1) The process speed was set to 210 mm / sec by changing the gear and software of the evaluation machine main body.

  (2) As a cartridge used for evaluation, the product toner was extracted from each commercially available color cartridge in FIG. 1, and the inside was cleaned by air blow. After that, 280 g of black toner (Bk-1), yellow toner (Y-1), magenta toner (M-1), and cyan toner (C-1) were filled in the modified cartridge corresponding to each color for evaluation. It was. The developing roller and the toner supply roller are configured to rotate in the counter direction at the nip portion.

  (3) The aforementioned acrylic resin coated belt was used as the intermediate transfer belt.

  (4) The software of the fixing device was changed so that the heating temperature could be controlled at 200 ° C. ± 30 ° C. The evaluation method was the same as in Example 1. The evaluation results are shown in Table 5.

  1 Photosensitive drum (electrophotographic photosensitive member), 2 charging roller, 3 scanner unit (exposure device), 4 developing unit (developing device), 5 intermediate transfer belt, 6 cleaning member, 7 process cartridge, 8 primary transfer roller, 9 Secondary transfer roller, 10 fixing device, 11 intermediate transfer belt cleaning device, 12 recording material, 51 driving roller, 52 secondary transfer counter roller, 53 tension roller, 100 image forming device

Claims (7)

(I) A first electrostatic latent image is formed on the electrostatic latent image carrier, and the first toner is selected from a group consisting of cyan toner, magenta toner, yellow toner, and black toner. An electrostatic latent image is developed to form a first toner image on the electrostatic latent image carrier, and the first toner image is primarily transferred to an intermediate transfer member;
(Ii) A second electrostatic latent image is formed on the electrostatic latent image carrier, and a second other than the first toner selected from the group consisting of cyan toner, magenta toner, yellow toner, and black toner. The second electrostatic latent image is developed with the toner to form a second toner image on the electrostatic latent image carrier, and the second toner image is formed on the intermediate transfer member. Primary transfer over the image,
(Iii) forming a third electrostatic latent image on the electrostatic latent image bearing member, and the first toner and the second toner selected from the group consisting of cyan toner, magenta toner, yellow toner, and black toner The third electrostatic latent image is developed with a third toner other than the first toner to form a third toner image on the electrostatic latent image carrier, and the third toner image is formed on the intermediate transfer member. Primary transfer over the first toner image and the second toner image,
(Iv) forming a fourth electrostatic latent image on the electrostatic latent image carrier, the first toner selected from the group consisting of cyan toner, magenta toner, yellow toner, and black toner; The fourth electrostatic latent image is developed with a toner other than the first toner and the fourth toner other than the third toner to form a fourth toner image on the electrostatic latent image carrier, and the fourth toner The image is primarily transferred over the first toner image, the second toner image, and the third toner image on the intermediate transfer member,
(V) Secondary transfer of the first to fourth toner images on the intermediate transfer member onto a transfer material, and heating and fixing the first to fourth toner images on the transfer material. A full-color image forming method in which a full-color image is formed on the transfer material, and residual transfer toner remaining on the intermediate transfer member after secondary transfer is removed using a cleaning blade in contact with the surface of the intermediate transfer member Because
The black toner is 3.0 parts by mass or more and 50.0 parts by mass or less with respect to 100.0 parts by mass of toner particles containing a binder resin, carbon black, and a release agent and untreated silica fine particles. A silica fine particle A having a carbon-based immobilization ratio of the silicone oil of 50% or less,
The cyan toner, the magenta toner, and the yellow toner are each composed of toner particles containing a binder resin, a colorant, and a release agent, and 100.0 parts by mass of untreated silica fine particles. Contains silica fine particles treated with 0 to 50.0 parts by mass of silicone oil, and contained in at least one toner selected from the group consisting of the cyan toner, the magenta toner, and the yellow toner The image forming method, wherein the silica fine particles contain silica fine particles B having a fixing ratio of 60% or more based on carbon of the silicone oil.   For the cyan toner, the magenta toner, and the yellow toner, the endothermic amount (J / g) derived from the release agent measured by the first scanning of the differential scanning calorimeter (DSC) is H1 and H2. 2. The image forming method according to claim 1, wherein the silica fine particles A are contained when H <b> 1 − H <b> 2 ≦ 1.45, where H <b> 2 is an endothermic amount (J / g) obtained by scanning.   The image forming method according to claim 1, wherein the silica fine particles A and B have a number average particle diameter (Dn) of primary particles of 5.0 nm or more and 15.0 nm or less.   The image forming method according to claim 1, wherein the silica fine particles A are surface-treated with silicone oil after surface treatment with at least one of alkoxysilane and silazane.   5. The image forming method according to claim 1, wherein the silica fine particles B are surface-treated with at least one of alkoxysilane and silazane after surface treatment with silicone oil. The releasing agent is, image formation according to any one of claims 1 to 5, an endothermic peak derived from the releasing agent to be measured, having a 60 ° C. 80 ° C. less than the differential scanning calorimetry (DSC) Method. The toner image formation on the electrostatic latent image carrier is arranged to be in contact with the developer carrier that carries the toner, and the supply member that supplies the toner to the developer carrier. The developer carrying body and the supply member are rotated in the same direction at a nip portion where each surface abuts . Image forming method.

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