JP5387946B2 - Method for producing surface smoothing toner in aqueous medium - Google Patents

Description

  The present invention relates to a toner, an image forming method using the toner, and a process cartridge.

  In recent years, in the field of electrophotographic image forming technology, competition for development of a color image forming apparatus (high quality color image forming technology) capable of high-speed image formation and high image quality is intensifying. For this reason, in order to obtain a full-color image at a high speed, a plurality of electrophotographic photosensitive members are arranged in series in the image forming method, and an image for each color component is formed on each electrophotographic photosensitive member, and is superimposed on the intermediate transfer member. Many so-called tandem systems that collectively transfer onto a recording material have been adopted (for example, Patent Document 1 and Patent Document 2). When an intermediate transfer member is used, if background stains occur on the electrophotographic photosensitive member during development, there is an effect of preventing the background stains from being transferred directly to a recording material such as paper. The system to be used passes through two transfer processes: a transfer process from an electrophotographic photosensitive member to an intermediate transfer body (primary transfer) and a transfer process to obtain a final image from the intermediate transfer body (secondary transfer). Therefore, transfer efficiency is lowered.

  On the other hand, in addition to the above problems, there is a demand for higher-quality full-color image formation, and developers have been designed for higher image quality. In order to meet the demand for higher image quality, particularly full-color image quality, toners are increasingly becoming smaller in particle size and are being studied to faithfully reproduce latent images. To reduce the particle size, a toner manufacturing method using a polymerization method has been proposed as a means for controlling the toner to have a desired toner shape and surface structure. (For example, Patent Document 3 and Patent Document 4). In the case of the polymerization toner, in addition to controlling the particle size of the toner particles, shape control is possible. In addition, by reducing the particle size together with this, the reproducibility of dots and fine lines can be improved, the pile height (image layer thickness) can be lowered, and higher image quality can be expected.

  However, when a small particle size toner is used, the non-electrostatic adhesion force between the toner particles and the electrophotographic photosensitive member or between the toner particles and the intermediate transfer member is increased, so that the transfer efficiency is likely to further decrease. For this reason, when a small-diameter toner is used in a high-speed full-color image forming apparatus, a decrease in transfer efficiency particularly in secondary transfer becomes significant. The reason for this is that non-electrostatic adhesion to the intermediate transfer member per toner particle is increasing due to the reduction in toner particle size, and in the secondary transfer, a plurality of color toners are superimposed. This is because the time during which the toner particles are subjected to the transfer electric field at the nip portion of the secondary transfer is shortened as the speed is increased, which makes it difficult to transfer the toner particles.

  In order to address the above problems, it is conceivable to further increase the transfer electric field of the secondary transfer. However, if the transfer electric field is excessively increased, the transfer may be caused by the occurrence of discharge when the intermediate transfer member and the recording material are peeled off. There is a limit as efficiency decreases. In addition, it is conceivable to increase the time during which the toner particles are subjected to the transfer electric field by increasing the width of the nip portion of the secondary transfer. However, in the case of a contact-type voltage application method such as a bias roller, the nip width is increased. The only way to achieve this is to either increase the contact pressure of the bias roller or increase the roller diameter of the bias roller. Increasing the contact pressure has a limit due to the relationship with the image quality, and increasing the roller diameter has a limit due to the relationship with the downsizing of the apparatus. Further, in the case of a non-contact voltage application method using a charger or the like, there is a limit because the nip width of secondary transfer must be increased by increasing the number of chargers. For this reason, it can be said that it is practically impossible to increase the nip width until a transfer efficiency higher than this is obtained, particularly in a high-speed machine.

  In contrast, as a means for reducing the non-electrostatic adhesion between the toner particles and the electrophotographic photosensitive member, or between the toner particles and the intermediate transfer member, the type and amount of the additive are adjusted (especially addition with a large particle size). Have been proposed. (For example, Patent Document 5 and Patent Document 6). By this method, the toner particles can obtain the effect of reducing the non-electrostatic adhesion force and improve the transfer efficiency, and also can obtain the effects of improving the development stability and cleaning.

  Initially, the toner particles described above can improve the transfer efficiency of the image forming apparatus. However, when the toner has been subjected to mechanical stress such as stirring for a long time in the developing device of the image forming apparatus, the additive is buried in the toner base particles or enters the minute unevenness present on the toner particle surface. As a result, the effect of reducing the adhesive force by the additive is not exhibited, and the transfer efficiency of the image forming apparatus is lowered. In particular, in the case of a high-speed machine, since the stirring in the developing device is intense, this mechanical stress is large, and the embedding and entering of the additive into the toner base are likely to be accelerated. For this reason, it is assumed that transfer efficiency is lowered at a relatively early stage.

For this reason, in order to maintain high transfer efficiency stably over a long period of time in a high-speed machine, the toner can be present on the surface without being embedded or entering the toner base particles even under mechanical stress. It is necessary to control the surface property.
Japanese Patent Application Laid-Open No. 07-209952 JP 2000-077551 Japanese Patent No. 3640918 Japanese Patent Laid-Open No. 06-250439 JP 2001-0666820 A Japanese Patent No. 3692929

  The present invention has been made in view of the current state of the art, and in a high-speed full-color image forming method, toner that improves transfer efficiency, eliminates image defects during each transfer, and outputs an image with good reproducibility in the long term. And a full-color image forming method using the toner, and a process cartridge.

The present invention is solved by the following (1) to ( 11 ).
(1) “In a method for producing a toner for obtaining a toner by surface-treating colored particles, a step of preparing a colored particle dispersion by dispersing colored particles in an aqueous medium containing at least a surfactant; and the colored particles a Dressings containing surface treatment step of heating the dispersion, between the colored particle dispersion step the colored particle surface treatment step of adjusting the includes the step of further washing the colored particles, the surface treatment step, the A step of reducing irregularities on the surface of the toner base particles, wherein the amount of the surfactant in the colored particle dispersion in the surface treatment step is 0.1 to 2.0 times the critical micelle concentration of the surfactant. And a heating method (T1) in the surface treatment step is −10 ° C. or more and less than 10 ° C. with respect to the glass transition temperature (Tg) of the toner ”,
(2) “a step of preparing a colored particle dispersion by granulating a toner material mixture in an aqueous medium containing a surfactant, a colored particle surface treatment step of heating the colored particle dispersion, a surface from the dispersion the treated colored particles were filtered, to obtain the toner base particles and dried, and treated with an external additive to toner base particles to obtain a toner is Dressings containing, the step of adjusting the colored particle dispersion And a step of washing the colored particles between the colored particle surface treatment step, and the surface treatment step is a step of reducing irregularities on the surface of the toner base particles, and the colored particle dispersion in the colored particle surface treatment step The amount of surfactant in the liquid is 0.1 to 2.0 times the critical micelle concentration of the surfactant, and the heating temperature (T1) is −10 ° C. with respect to the glass transition temperature (Tg) of the toner. 10 ℃ Method for producing a toner, which is a fully "
( 3 ) “The step of adjusting the colored particle dispersion is to dissolve or disperse at least a resin material, a colorant, a release agent, and a toner material in an organic solvent, and the dissolved or dispersed solution is an aqueous system containing a surfactant. The method for producing a toner according to (1) or (2) above, which is a step of adjusting a colored particle dispersion by dispersing in a medium ”,
( 4 ) “The step of preparing the colored particle dispersion is carried out by using an organic solvent as a toner material containing at least unmodified polyester resin, urea or urethane-modified polyester resin, amine, colorant, and release agent. Polyester resin having a urea or urethane bond obtained by dissolving or dispersing in, dispersing the dispersion or dispersion in an aqueous medium containing a surfactant, and reacting the modified polyester resin with the amine The method for producing a toner according to any one of ( 1 ) to ( 3 ), wherein the toner is a step of preparing a colored particle dispersion containing
( 5 ) "Toner obtained by the method for producing toner according to (1) to ( 4 )",
( 6 ) “The ratio Sbet / Dv between the BET specific surface area (Sbet) of the toner and the volume average particle diameter (Dv) of the toner is 2.0 × 10 ⁵ m / g or more and less than 4.0 × 10 ⁵ m / g. The toner according to item ( 5 ), wherein:
( 7 ) "The toner according to any one of ( 5 ) or ( 6 ), wherein the average circularity of the toner is 0.940 or more and less than 0.970",
( 8 ) "The toner according to any one of ( 5 ) to ( 7 ) above, wherein the volume average particle diameter of the toner is 1.0 µm or more and less than 6.0 µm",
( 9 ) “Charging step of charging the electrophotographic photosensitive member with a charging unit, an exposure step of forming an electrostatic latent image on the charged electrophotographic photosensitive member with an exposing unit, and the formation of the electrostatic latent image. A developing step of forming a toner image on the electrophotographic photosensitive member using toner by a developing unit, and a primary transfer step of transferring the toner image formed on the electrophotographic photosensitive member onto an intermediate transfer member by a primary transferring unit. A secondary transfer step of transferring the toner image transferred onto the intermediate transfer member onto a recording material by a secondary transfer means, and fixing the toner image transferred onto the recording material with a heat and pressure fixing member A fixing step for fixing the toner image on the recording material by the means, and cleaning residual toner adhering to the surface of the electrophotographic photosensitive member having the toner image transferred onto the intermediate transfer member by the primary transfer means by the cleaning means. And a cleaning step that a full-color image forming method, wherein the toner in the developing step is a toner according to any one of the first (5) section to the (8) term "
( 10 ) “In the secondary transfer step, the linear velocity of transfer of the toner image to the recording material is 300 to 1000 mm / sec, and the transfer time at the nip portion of the secondary transfer means is 0.5 to 20 msec. The full-color image forming method according to item ( 9 ), "
( 11 ) “The full color image forming method according to item ( 9 ) or ( 10 ), wherein the tandem electrophotographic image forming process is employed”.

  As will be apparent from the following detailed and specific description, according to the present invention, in a high-speed full-color image forming method, transfer efficiency is improved, image defects are eliminated at the time of each transfer, and long-term reproducible images. In particular, it is possible to provide a method for producing a toner that outputs toner, a full-color image forming method using the toner, and a process cartridge.

  The best mode for carrying out the present invention will be described with reference to the drawings as necessary. Note that it is easy for a person skilled in the art to make other embodiments by changing or correcting the present invention within the scope of the claims, and these changes and modifications are included in the scope of the claims. The following description is an example of a preferred embodiment of the present invention and is not intended to limit the scope of the claims.

  As described above, the toner production method of the present invention includes a step of dispersing colored particles in an aqueous medium containing at least a surfactant to prepare a colored particle dispersion, and a surface for heating the colored particle dispersion. Including a treatment step, the amount of the surfactant in the colored particle dispersion in the surface treatment step is 0.1 to 2.0 times the critical micelle concentration of the surfactant, and in the surface treatment step The heating temperature (T1) is −10 ° C. or more and less than 10 ° C. with respect to the glass transition temperature (Tg) of the toner. Such a toner production method of the present invention typically prepares a colored particle dispersion in which colored particles for toner containing at least a binder resin and a colorant are dispersed in an aqueous medium containing a surfactant. And a surface treatment step in which the colored particle dispersion is heated, and the amount of the surfactant in the colored particle dispersion in the surface treatment step is 0.1 to 2 times the critical micelle concentration. And the heating temperature (T1) in the surface treatment step is −10 ° C. or more and less than 10 ° C. with respect to the glass transition temperature (Tg) of the toner. Here, in the present invention, the “toner base” is assumed to be a particle after the surface treatment is completed and before the external addition treatment, and a particle that has not been subjected to the previous surface treatment is referred to as a “colored particle”.

  We have already removed an organic solvent liquid containing a crosslinkable low molecular weight binder resin component and a toner material such as a colorant from an O / W type dispersion obtained by emulsifying and dispersing it in an aqueous dispersion. Many toner manufacturing technologies have been proposed that contain toner base particles by solvent treatment. In these technologies, fine inorganic and / or resin fine particles are dispersed as an aqueous dispersion. A lot of those using an aqueous dispersion are also included. Regardless of the order, the aging step of the toner base particles, the cleaning to remove the surfactant derived from the O / W type emulsion dispersion by washing the toner base particles. Several toner manufacturing techniques including a process and a surfactant treatment process for toner base particles are also included. In the process of further studying these, the present inventors controlled the amount of surfactant during aging to a smaller range, and when aging was performed, the formation of minute irregularities was adjusted and the result was excellent in surface smoothing. Based on this knowledge, it has been discovered that such a result is applicable to other chemical toner manufacturing techniques, and that it is also applicable to toner manufacturing using pulverized toner. Further studies have been made and the toner production method of the present invention has been completed.

  The toner obtained by the above production method is heated softly in water containing a small amount of surfactant at a temperature close to the glass transition temperature of the toner, so that the binder resin component contained in the toner toner colored particles is weakened and softened. Since it flows in a very small region so as to reduce the surface area, minute unevenness of several nm to several hundred nm existing on the surface of the toner base particle can be relaxed and smoothed. Normally, when the toner due to stirring in the developing device is subjected to mechanical stress, the external additive enters the minute irregularities on the surface of the toner particles, thereby increasing the non-electrostatic adhesion force and the transfer efficiency. descend. In particular, when a toner having a small particle diameter is used, the non-electrostatic adhesion force between the toner particles and the electrophotographic photosensitive member or between the toner particles and the intermediate transfer member is increased, so that the transfer efficiency is further lowered. Furthermore, when a small particle size toner is used in a high-speed machine, non-electrostatic adhesion to the intermediate transfer member is increased by reducing the particle size of the toner, and the transfer nip portion, It is known that the transfer efficiency in the secondary transfer is significantly reduced because the time during which the toner particles are subjected to the transfer electric field in the nip portion of the secondary transfer is shortened.

  In the toner obtained by the production method of the present invention, since the fine irregularities on the surface of the toner particles are alleviated by the surface treatment process, the function deterioration due to the external additive entering the irregularities of the toner particles as described above is prevented. Thus, even when the toner is subjected to mechanical stress, the increase in non-electrostatic adhesion can be suppressed and high transfer efficiency can be obtained. In addition, since the surface area of the toner per unit weight becomes smaller than that of the toner surface where minute irregularities exist because the minute irregularities on the toner surface are alleviated, external addition to the toner surface when a certain amount of external additive is added. The effective coverage of the agent increases. As a result, the effect of reducing the non-electrostatic adhesion force by the external additive is increased, so that even when the toner is subjected to mechanical stress, an increase in the non-electrostatic adhesion force can be suppressed and high transfer efficiency can be obtained. .

  In the present invention, the heat treatment is carried out in water. However, when it is carried out in the gas phase, the toner particles are likely to be fused even at the same temperature as in water, and the toner particle size distribution may be deteriorated. Further, when the same treatment is performed in the gas phase, a higher heating temperature is required, and the toner particles are further fused. When the surfactant concentration is higher than twice the critical micelle concentration, the surfactant protects minute irregularities on the toner surface when heated, so that the toner surface is not smoothed and high transfer efficiency is obtained. I can't. When the surfactant concentration is less than 0.1 times the critical micelle concentration, not only the unevenness of several nm to several hundred nm on the toner surface but also the unevenness of several μm is alleviated, so that the blade cleaning property is improved. It will get worse. On the other hand, when the concentration is less than 0.1 times the critical micelle concentration, the toner particles are likely to be fused with each other by heating in the surface treatment process, and the particle size distribution of the toner may be deteriorated.

  When the heating temperature in the surface treatment step is less than 10 ° C. with respect to the glass transition temperature of the toner, since the binder resin in the toner does not soften, the toner surface is not smoothed and high transfer efficiency is obtained. Absent. Further, when the heating temperature is 10 ° C. or higher with respect to the glass transition temperature, the toner particle is fused with the softening of the toner resin at the low surfactant concentration as in the present invention. Will worsen.

  The production method of the present invention preferably includes a step of removing a surfactant obtained by adjusting a toner material containing at least a binder resin and a colorant in an aqueous medium containing a surfactant. In the case of a toner obtained in an aqueous medium, since the toner material has an affinity with water as a dispersion solvent, the toner surface can be more easily smoothed by heating. In addition, since the manufacturing process includes a state in which the toner is dispersed in the aqueous medium and a step of removing the surfactant, an increase in the manufacturing process associated with the surface treatment step can be suppressed.

  Moreover, it is preferable that the binder resin used for this invention contains a polyester resin. Polyester resin is superior in impact resistance compared to other resins even when a low softening point is used to improve low-temperature fixability, so it can improve the stress resistance of the toner and has a hydrophilic group in the molecular structure. Since it has a relatively high polarity, it has excellent affinity with an aqueous medium, and it is easier to achieve surface smoothing.

Further, the toner obtained by the production method of the present invention has a ratio Sbet / Dv between the BET specific surface area (Sbet) of the toner and the volume average particle diameter (Dv) of the toner of 2.0 × 10 ⁵ m / g or more and 4.0 ×. It is preferably less than 10 ⁵ m / g. When Sbet / Dv is less than 2.0 × 10 ⁵ m / g, the shape of the toner particles becomes close to a true sphere, and the cleaning ability of the transfer residual toner on the photosensitive member and the intermediate transfer member may be inferior. When Sbet / Dv is 4.0 × 10 ⁵ m / g or more, the fine irregularities on the toner surface are not sufficiently relaxed, and high transfer efficiency may not be obtained.

  The toner obtained by the production method of the present invention preferably has an average circularity of 0.940 or more and less than 0.970. When it is 0.970 or more, the shape of the toner particles is close to a true sphere, and the cleaning ability of the transfer residual toner on the photosensitive member and the intermediate transfer member may be poor. If it is less than 0.940, since there are many relatively large irregularities of about several hundred nm on the toner surface, high transfer efficiency can be achieved even if minute irregularities of several nm to several hundred nm are alleviated in the present invention. It may not be obtained.

  The particle size of the toner obtained by the production method of the present invention is controlled so that the volume average particle size is 1 to 6 μm. In particular, the toner preferably has a volume average particle diameter of 2 to 5 μm. If it is smaller than 1 μm, toner dust is likely to occur in primary transfer and secondary transfer. Conversely, if it is larger than 6 μm, dot reproducibility becomes insufficient, and the graininess of the halftone portion also deteriorates. A high-definition image cannot be obtained.

(Critical micelle concentration)
The critical micelle concentration of the surfactant with respect to the aqueous medium can be determined by a surface tension method, an electric conductivity method, a dye method, or the like.
For example, it measured using the surface tension meter Sigma (made by KSV Instruments), and analyzed using the analysis program in a Sigma system. Surfactant was added dropwise by 0.01 wt% with respect to the aqueous medium, and the interfacial tension after stirring and standing was measured. From the obtained surface tension curve, the surfactant concentration at which the interfacial tension did not decrease even when the surfactant was dropped was calculated as the critical micelle concentration.

(Measurement of surfactant concentration)
The measurement of the surfactant concentration in the toner dispersion can be performed, for example, by the following method.

  The surfactant used in the toner dispersion is dropped 0.01% by weight on an aqueous medium, the electrical conductivity at that time is measured, and a calibration curve for the surfactant is created. The electrical conductivity of the toner dispersion is measured, and the surfactant concentration in the toner dispersion can be calculated from the calibration curve obtained.

(BET specific surface area)
The BET specific surface area of the toner particles was measured using an automatic specific surface area / pore distribution measuring device (TriStar 3000: manufactured by Shimadzu Corporation). About 0.5 g of a sample was weighed in a sample cell, and this was vacuum-dried for 24 hours with a pretreatment smart prep (manufactured by Shimadzu Corporation) to remove impurities and moisture on the sample surface. The pretreated sample is set in TriStar 3000, and the relationship between the nitrogen gas adsorption amount and the relative pressure is obtained. From this relationship, the BET specific surface area of the sample can be obtained by the BET multipoint method.

(Volume average particle size)
The volume average particle size (Dv) was measured with a particle size measuring device (“Multisizer III” manufactured by Beckman Coulter, Inc.) with an aperture diameter of 100 μm, and analyzed with analysis software (Beckman Coulter Multisizer 3 Version 3.51). . Specifically, 0.5 ml of 10 wt% surfactant (alkylbenzene sulfonate Neogen SC-A; Daiichi Kogyo Seiyaku) was added to a glass 100 ml beaker, 0.5 g of each toner was added, and the mixture was stirred with a micropartel. Subsequently, 80 ml of ion-exchanged water was added. The obtained dispersion was subjected to a dispersion treatment for 10 minutes with an ultrasonic disperser (W-113MK-II, manufactured by Honda Electronics Co., Ltd.). The dispersion was measured using the Multisizer III and Isoton III (manufactured by Beckman Coulter) as the measurement solution. In the measurement, the toner sample dispersion was dropped so that the concentration indicated by the apparatus was 8 ± 2%. In this measurement method, it is important that the concentration is 8 ± 2% from the viewpoint of the reproducibility of the particle size. Within this concentration range, no error occurs in the particle size.

(Average circularity)
The average circularity of the toner is defined by the following formula (A).

  Measurement was performed using a flow type particle image analyzer (“FPIA-2100”; manufactured by Sysmex Corporation), and analysis was performed using analysis software (FPIA-2100 Data Processing Program for FPIA version 00-10). Specifically, 0.1 to 0.5 ml of 10 wt% surfactant (alkylbenzene sulfonate Neogen SC-A; Daiichi Kogyo Seiyaku) is added to a glass 100 ml beaker, and each toner 0.1 to 0 is added. 0.5 g was added and stirred with a microspatel, and then 80 ml of ion-exchanged water was added. The obtained dispersion was subjected to a dispersion treatment for 3 minutes with an ultrasonic disperser (Honda Electronics). The shape and distribution of the toner were measured using the FPIA-2100 until the density of the dispersion was 5000 to 15000 / μl. In this measurement method, it is important that the concentration of the dispersion liquid is 5000 to 15000 / μl from the viewpoint of measurement reproducibility of the average circularity. In order to obtain the dispersion concentration, it is necessary to change the conditions of the dispersion, that is, the amount of surfactant to be added and the amount of toner. The amount of the surfactant varies depending on the hydrophobicity of the toner as in the measurement of the toner particle diameter described above. If it is added in a large amount, noise due to bubbles is generated, and if it is too small, the toner cannot be sufficiently wetted. It will be enough. Further, the toner addition amount differs from the particle size, and it is necessary to decrease the small particle size and increase the large particle size. When the toner particle size is 3 to 7 μm, the toner amount is 0.1 to 0. By adding 0.5 g, the dispersion concentration can be adjusted to 5000 to 15000 / μl.

(Glass-transition temperature)
Here, the glass transition temperature (Tg) of the toner can be measured using, for example, a DSC system (differential scanning calorimeter) (“DSC-60” manufactured by Shimadzu Corporation).
First, about 5.0 mg of a polyester resin was placed in an aluminum sample container, and the sample container was placed on a holder unit and set in an electric furnace. Subsequently, it heated from 20 degreeC to 150 degreeC with the temperature increase rate of 10 degree-C / min in nitrogen atmosphere. Thereafter, the temperature is lowered from 150 ° C. to 0 ° C. at a rate of temperature decrease of 10 ° C./min, further heated to 150 ° C. at a rate of temperature increase of 10 ° C./min, and a differential scanning calorimeter (“DSC-60” manufactured by Shimadzu Corporation) DSC curve was measured. From the obtained DSC curve, using the analysis program in the DSC-60 system, the shoulder of the DSC curve at the second temperature rise can be selected, and the glass transition temperature (Tg) of the toner can be calculated.

[Each toner material constituting the present invention]
<Binder resin>
Even when the binder resin has a low softening point for improving low-temperature fixability, it has superior impact resistance compared to other resins, so it can improve the stress resistance of the toner and has a molecular structure. Since it has a hydrophilic group in it and has a relatively high polarity, it has excellent affinity with an aqueous medium, and it is easier to achieve surface smoothing. A polyester resin is preferred because good low-temperature fixability can be obtained. In addition to the binder resin, a colorant is preferably included, and a release agent such as wax and other subcomponents as described below can be further included.

-Polyester resin-
There is no restriction | limiting in particular as said polyester resin, The molecular weight of a polyester resin, a structural monomer, etc. can be suitably selected according to the objective. The polyester resin can be obtained by dehydration condensation of a polyhydric alcohol and a polyvalent carboxylic acid. Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, , 6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, divalent alcohols obtained by adding cyclic ethers such as ethylene oxide and propylene oxide to bisphenol A, etc. Is mentioned. In order to crosslink the polyester resin, sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol 1,2,5-pentatriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxybenzene, etc. It is preferable to use a trivalent or higher alcohol together.

  Examples of the polyvalent carboxylic acid include benzene dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid or anhydrides thereof, and alkyldicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid, or anhydrides thereof. Unsaturated dibasic acids such as maleic acid, citraconic acid, itaconic acid, alkenyl succinic acid, fumaric acid, mesaconic acid, etc., unsaturated maleic anhydride, citraconic anhydride, itaconic anhydride, alkenyl succinic anhydride, etc. Dibasic acid anhydride, trimet acid, pyrometic acid, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid Acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicar Xyl-2-methyl-2-methylenecarboxypropane, tetrakis (methylenecarboxy) methane, 1,2,7,8-octanetetracarboxylic acid, emporic trimer acid, anhydrides thereof, partial lower alkyl esters, etc. It is done.

  In addition, the polyester resin has at least one peak in a molecular weight range of 3,000 to 50,000 in the molecular weight distribution of components soluble in THF from the viewpoint of toner fixing property and offset resistance. Preferably, it has at least one peak in a region having a molecular weight of 5,000 to 20,000. Further, the component of the polyester resin soluble in THF preferably has a content of a component having a molecular weight of 100,000 or less of 60 to 100% by mass. Here, the molecular weight distribution of the polyester resin can be measured, for example, by gel permeation chromatography (GPC) using THF as a solvent.

  The glass transition temperature (Tg) of the polyester resin is preferably 55 to 80 ° C., and more preferably 60 to 75 ° C. from the viewpoint of toner storage stability. When the Tg is 55 to 80 ° C., the stability of the toner during high-temperature storage is excellent, and the toner has excellent low-temperature fixability.

  Further, the binder resin may contain a resin other than the polyester resin. Examples of the resin other than the polyester resin include homopolymers or copolymers such as styrene monomers, acrylic monomers, and methacrylic monomers, polyol resins, phenol resins, silicone resins, polyurethane resins, Examples thereof include polyamide resin, furan resin, epoxy resin, xylene resin, terpene resin, coumarone indene resin, polycarbonate resin, and petroleum resin. Resins other than the polyester resin may be used alone or in combination of two or more. There is no restriction | limiting in particular as said mold release agent, Although it can select suitably according to the objective, The low melting-point mold release agent whose melting | fusing point is 60-90 degreeC is preferable. The low melting point release agent, when dispersed with the resin, effectively acts as a release agent between the fixing roller and the toner interface, thereby preventing oilless (a release agent such as oil on the fixing roller). Even if it is not applied), the hot offset property is good. In particular, in the present invention, it is assumed that the fixing roller temperature is used at a set temperature lower than the conventional temperature by fixing the toner at a low temperature by introducing a fixing auxiliary component. Therefore, it is necessary to exhibit releasability at a lower temperature. Therefore, a release agent having a melting point of 90 ° C. or higher is preferably used. In addition, when the melting point of the release agent is less than 60 ° C., the high-temperature storage stability of the toner may be inferior, and the obtained image may be deteriorated.

  Examples of the waxes and waxes include plant waxes such as carnauba wax, cotton wax, wood wax and rice wax; animal waxes such as beeswax and lanolin; mineral waxes such as ozokerite and cercin; paraffin and micro wax And natural waxes such as petroleum waxes such as crystallin and petrolatum. In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax, polyethylene wax, and polypropylene; synthetic waxes such as esters, ketones, and ethers; Furthermore, fatty acid amide compounds such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, chlorinated hydrocarbon; low molecular weight crystalline polymer resin, poly-n-stearyl methacrylate, poly-n -Polyacrylate homopolymer or copolymer such as lauryl methacrylate (eg, n-stearyl acrylate-ethyl methacrylate copolymer); crystalline polymer having a long alkyl group in the side chain, etc. Good.

  These may be used alone or in combination of two or more. Among the release agents, as the release agent of the present invention, hydrocarbon waxes such as paraffin, polyethylene, and polypropylene are preferable. Since the hydrocarbon wax has low compatibility with the fixing auxiliary component of the present invention and can act independently without impairing the functions of each other, sufficient low-temperature fixability can be obtained.

  The colorant can be appropriately selected from known dyes and pigments according to the purpose. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium Yellow, yellow iron oxide, ocher, yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG) , Vulcan Fast Yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Lead Red, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R, Para red Parachloroorthonitroaniline red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine B, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Tolujing Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon, Oil Red, Quinacridone , Pyrazolone red, polyazo red, chrome vermilion, benzidine orange, perinone orange, oil orange, cobalt blue, cerulean blue, alkali blue rake, peacock blue rake, Victoria blue rake, metal free phthalocyanine blue, phthalocyanine blue, fast sky blue , Indanthrene Blue (RS, BC), Indigo, Ultramarine, Bitumen, Anthraquinone Blue, Fast Violet B, Methyl Violet Lake, Cobalt Purple, Manganese Purple, Dioxane Violet, Anthraquinone Violet, Chrome Green, Zinc Green, Chrome Oxide, Pyridian , Emerald Green, Pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Examples include green lake, phthalocyanine green, anthraquinone green, titanium oxide, zinc white, lithopone, and the like.

  The content of the colorant in the toner material is preferably 1 to 15% by weight, and more preferably 3 to 10% by weight. If the content is less than 1% by weight, the coloring power of the toner may be reduced. If the content exceeds 15% by weight, poor dispersion of the pigment in the toner will occur. The characteristics may be degraded. The colorant may be used as a master batch combined with a resin. Examples of such resins include polyesters, styrene or substituted polymers thereof, styrene copolymers, polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, and epoxy resins. , Epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, aliphatic hydrocarbon resin, alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax 2 or more types may be used in combination.

  Examples of the polymer of styrene or a substituted product thereof include polystyrene, poly (p-chlorostyrene), and polyvinyl toluene. Examples of the styrene copolymer include styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer. Copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-methacrylic copolymer Acid butyl copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene- Acrylonitrile-indene copolymer, steel Down - maleic acid copolymer, styrene - maleic acid ester copolymers and the like.

  The master batch can be manufactured by applying a high shear force and mixing or kneading the resin and the colorant. At this time, it is preferable to add an organic solvent in order to enhance the interaction between the colorant and the resin. Also, the so-called flushing method is preferable in that the wet cake of the colorant can be used as it is, and there is no need to dry it. The flushing method is a method in which an aqueous paste containing water of a colorant is mixed or kneaded together with a resin and an organic solvent, and the colorant is transferred to the resin side to remove water and the organic solvent. For mixing or kneading, for example, a high shear dispersion device such as a three-roll mill can be used.

  The toner of the present invention can further contain a charge control agent, inorganic fine particles, a cleaning improver, a magnetic material, and the like.

  Examples of the charge control agent include nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts). ), Alkylamide, simple substance or compound of phosphorus, simple substance or compound of tungsten, fluorine-based surfactant, metal salt of salicylic acid, metal salt of salicylic acid derivative, and the like.

  Commercially available products may be used as the charge control agent. For example, bontron 03 of nigrosine dye, bontron P-51 of quaternary ammonium salt, bontron S-34 of metal-containing azo dye, oxynaphthoic acid metal complex E-82, E-84 of salicylic acid metal complex, E-89 of phenol-based condensate (above, manufactured by Orient Chemical Co., Ltd.), TP-302, TP-415 of quaternary ammonium salt molybdenum complex (above, Hodogaya) Chemical Industry Co., Ltd.) Quaternary ammonium salt copy charge PSY VP2038, Triphenylmethane derivative copy blue PR, Quaternary ammonium salt copy charge NEG VP2036, Copy charge NX VP434 (above, Hoechst), LRA-901 LR-147 which is a boron complex (manufactured by Nippon Carlit), copper lid Examples thereof include polymer compounds having functional groups such as Russianine, perylene, quinacridone, azo pigments, sulfonic acid groups, carboxyl groups, and quaternary ammonium bases.

  The content of the charge control agent in the toner composition is, for example, preferably 0.1 to 10% by weight, and more preferably 0.2 to 5% by weight with respect to the binder resin. If the content is less than 0.1% by weight, the charge controllability may not be obtained. If the content exceeds 10% by weight, the chargeability of the toner becomes too large and the effect of the main charge control agent is reduced. As a result, the electrostatic attraction force with the developing roller increases, which may lead to a decrease in toner fluidity and a decrease in image density.

The inorganic fine particles are used as an external additive for imparting fluidity, developability, chargeability and the like to the toner. Examples of inorganic fine particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, quartz sand, clay, mica, wollastonite, diatomaceous earth, Examples thereof include chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. The inorganic fine particles preferably have a primary particle size of 5 nm to 2 μm, more preferably 5 to 500 nm. The content of the inorganic fine particles in the toner is preferably 0.01 to 5.0% by weight, and more preferably 0.01 to 2.0% by weight. The inorganic fine particles are preferably surface-treated with a fluidity improver. As a result, the hydrophobicity of the inorganic fine particles is improved, and a decrease in fluidity and chargeability can be suppressed even under high humidity. Examples of the fluidity improver include, for example, a silane coupling agent, a silylating agent, a silane coupling agent having a fluorinated alkyl group, an organic titanate coupling agent, an aluminum coupling agent, silicone oil, and modified silicone oil. Is mentioned. Silica and titanium oxide are preferably surface-treated with a fluidity improver and used as hydrophobic silica and hydrophobic titanium oxide.
The cleaning property improver is used to facilitate removal of toner remaining on the photoreceptor and the primary transfer medium after transfer. Examples of the cleaning improver include fatty acid metal salts such as zinc stearate and calcium stearate, polymer fine particles produced by soap-free emulsion polymerization such as polymethyl methacrylate fine particles and polystyrene fine particles. The polymer fine particles preferably have a relatively narrow particle size distribution, and preferably have a volume average particle size of 0.01 to 1 μm.

  Examples of the magnetic material include iron powder, magnetite, and ferrite. The magnetic material is preferably white from the viewpoint of the color tone of the toner. The toner of the present invention is excellent in low-temperature fixability and offset resistance, and can form a high-quality image over a long period of time. Therefore, the toner of the present invention can be used in various fields, and is particularly preferably used for image formation by electrophotography.

-Toner production method-
The toner base particle production method can be appropriately selected from conventionally known toner production methods according to the purpose as long as it includes a surface smoothing treatment step in an aqueous medium. -A grinding method, a polymerization method, a dissolution suspension method, a spray granulation method, etc. are mentioned. Among them, since the toner material has an affinity with water as a dispersion solvent, it is easier to achieve smoothing of the toner particle surface by heating, and in the first place, the toner is dispersed in an aqueous medium. In addition, since it includes a step of removing the surfactant, the polymerization method and the dissolution suspension method are preferable from the viewpoint of suppressing an increase in the production process accompanying the surface treatment step.

-Kneading and grinding method-
In the kneading and pulverizing method, for example, a toner material containing at least a binder resin, a release agent, and a fixing auxiliary component is melt-kneaded, and the obtained kneaded material is pulverized and classified, whereby the base material of the toner is obtained. A method for producing particles. In the melt kneading, the toner materials are mixed, and the mixture is charged into a melt kneader and melt kneaded. As the melt kneader, for example, a uniaxial or biaxial continuous kneader or a batch kneader using a roll mill can be used. For example, a KTK type twin screw extruder manufactured by Kobe Steel, a TEM type extruder manufactured by Toshiba Machine Co., Ltd., a twin screw extruder manufactured by Casey Kay Co., Ltd., a PCM type twin screw extruder manufactured by Ikegai Co., Ltd. Used. This melt-kneading is preferably performed under appropriate conditions that do not cause the molecular chains of the binder resin to be broken. Specifically, the melt-kneading temperature is determined with reference to the softening point of the binder resin. If the temperature is higher than the softening point, cutting is severe, and if the temperature is too low, dispersion may not proceed.

  In the pulverization, the kneaded product obtained by the kneading is pulverized. In this pulverization, it is preferable that the kneaded material is first coarsely pulverized and then finely pulverized. At this time, a method of pulverizing by colliding with a collision plate in a jet stream, pulverizing particles by colliding with each other in a jet stream, or pulverizing with a narrow gap between a mechanically rotating rotor and a stator is preferably used.

  In the classification, the pulverized product obtained by the pulverization is classified and adjusted to particles having a predetermined particle diameter. The classification can be performed, for example, by removing the fine particle portion with a cyclone, a decanter, a centrifuge, or the like. After the pulverization and classification are completed, the pulverized product is classified in an air stream by a centrifugal force or the like to produce toner base particles having a predetermined particle size.

  Next, the external additive is externally added to the toner base particles. By mixing and stirring the toner base particles and the external additive using a mixer, the surface of the toner base particles is coated while being crushed. At this time, it is important from the viewpoint of durability that the external additives such as inorganic fine particles and resin fine particles are uniformly and firmly attached to the toner base particles.

-Polymerization method-
As a method for producing a toner by the polymerization method, for example, a toner material containing a modified polyester resin capable of at least urea or urethane bond, a release agent, and a fixing aid is dissolved or dispersed in an organic solvent. Then, this solution or dispersion is dispersed in an aqueous medium, subjected to polyaddition reaction, the solvent of this dispersion is removed, and the surfactant or the like is washed.

  Examples of the modified polyester resin capable of being bonded with urea or urethane include, for example, polyester prepolymer having an isocyanate group obtained by reacting a carboxyl group or a hydroxyl group at a terminal of a polyester with a polyvalent isocyanate compound (PIC). Can be mentioned. The modified polyester resin obtained by crosslinking and / or extending the molecular chain by the reaction of the polyester prepolymer with an active hydrogen group-containing compound such as amines improves the hot offset property while maintaining the low temperature fixability. be able to.

  Examples of the polyvalent isocyanate compound (PIC) include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane). Aromatic diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanates; And those blocked with oxime, caprolactam, and the like. These may be used individually by 1 type and may use 2 or more types together. The ratio of the polyvalent isocyanate compound (PIC) is preferably 5/1 to 1/1 as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group, 4/1 to 1.2 / 1 is more preferable, and 2.5 / 1 to 1.5 / 1 is still more preferable.

  The number of isocyanate groups contained per molecule in the polyester prepolymer (A) having the isocyanate group is preferably 1 or more, more preferably 1.5 to 3 on average, and 1.8 to 2.5 on average. Is more preferable.

  Examples of amines (B) to be reacted with the polyester prepolymer include a divalent amine compound (B1), a trivalent or higher polyvalent amine compound (B2), an amino alcohol (B3), an amino mercaptan (B4), an amino acid (B5). ), B1 to B5 amino groups blocked (B6), and the like. Examples of the divalent amine compound (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′-). Dimethyl dicyclohexyl methane, diamine cyclohexane, isophorone diamine, etc.); aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.) and the like. Examples of the trivalent or higher polyvalent amine compound (B2) include diethylenetriamine and triethylenetetramine. Examples of the amino alcohol (B3) include ethanolamine and hydroxyethylaniline. Examples of the amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan. Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid. Examples of the blocked B1-B5 amino group (B6) include ketimine compounds and oxazolidine compounds obtained from the amines of B1 to B5 and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). . Among these amines (B), B1 and a mixture of B1 and a small amount of B2 are particularly preferable.

  The ratio of the amines (B) is equivalent to the equivalent ratio [NCO] / [NHx of the isocyanate group [NCO] in the polyester prepolymer (A) having an isocyanate group and the amino group [NHx] in the amine (B). ] Is preferably 1/2 to 2/1, more preferably 1.5 / 1 to 1 / 1.5, and still more preferably 1.2 / 1 to 1 / 1.2.

  According to the method for producing a toner by the polymerization method as described above, a toner having a small particle diameter and a spherical shape can be produced at low cost with little environmental load.

(Surface treatment process)
The toner of the present invention includes a toner surface smoothing step of heating a toner dispersion liquid in which the toner is dispersed in an aqueous medium. In a toner prepared by a pulverization method or a spray granulation method, a toner dispersion can be obtained by adding a surfactant to an aqueous medium, adding the toner, and dispersing with a high-speed shearing disperser. In the polymerization method, it is preferable to carry out the surface treatment step after adjusting the amount of the surfactant in the toner dispersion to not more than twice the critical micelle concentration in the present invention, which is the surfactant concentration in the present invention.

(Aqueous medium)
The aqueous medium is not particularly limited and can be appropriately selected from known ones. For example, water, a solvent miscible with water, a mixture thereof, and the like can be used. Is particularly preferred. The solvent miscible with water is not particularly limited as long as it is miscible with water. For example, alcohol, dimethylformamide, tetrahydrofuran, cellosolves, lower ketones, and the like can be used. Examples of the alcohol include methanol, isopropanol, and ethylene glycol. Examples of lower ketones include acetone and methyl ethyl ketone. These may be used individually by 1 type and may use 2 or more types together.

  The developer of the present invention has the toner of the present invention, but may further have a component such as a carrier, and may be used as a one-component developer composed of toner, a two-component developer composed of toner and carrier, or the like. However, it is preferable to use a two-component developer in the high-speed printer and the like corresponding to the recent improvement in information processing speed from the viewpoint of improving the service life. Such a developer can be used in various known electrophotographic methods such as a magnetic one-component development method, a non-magnetic one-component development method, and a two-component development method. When the developer of the present invention is used as a one-component developer, even if the balance of the toner is performed, the fluctuation of the toner particle size is small, and the blade for filming the toner on the developing roller and thinning the toner The toner can be prevented from being fused to a member such as the above, and good and stable developability can be obtained even in the long-term use (stirring) of the developing device. Further, when the developer of the present invention is used as a two-component developer, even if the toner balance is maintained over a long period of time, there is little fluctuation in the particle size of the toner, and even in the long-term agitation in the developing device, it is good and stable Developability is obtained.

  The content of the carrier in the two-component developer is preferably 90 to 98% by weight, and more preferably 93 to 97% by weight. The carrier is not particularly limited, but preferably has a core material and a resin layer covering the core material. Examples of the core material include 50 to 90 emu / g manganese-strontium (Mn—Sr) -based material, manganese-magnesium (Mn—Mg) -based material, and two or more of them may be used in combination. In terms of securing image density, it is preferable to use a highly magnetized material such as iron powder (100 emu / g or more) or magnetite (75 to 120 emu / g) as the core material. In addition, a copper-zinc (Cu-Zn) system (30 to 80 emu / g) is used as a core material in that it can weaken the hitting of the photoconductor in which the toner is in a spiked state, and is advantageous in improving the image quality. It is preferable to use a weakly magnetized material such as

  The core material preferably has a volume average particle size (D50) of 10 to 150 μm, more preferably 20 to 80 μm. If D50 is less than 10 μm, fine particles increase in the particle size distribution of the carrier, so that the magnetization per particle may decrease and carrier scattering may occur. On the other hand, if D50 exceeds 150 μm, the specific surface area of the carrier may decrease and toner scattering may occur. As a result, the reproducibility of the solid portion may be deteriorated particularly in a full color with many solid portions.

  Examples of the material of the resin layer include amino resins, polyvinyl resins, polystyrene resins, halogenated olefin resins, polyester resins, polycarbonate resins, polyethylene resins, polyvinyl fluoride resins, polyvinylidene fluoride resins, polytrifluoro Ethylene resin, polyhexafluoropropylene resin, copolymer of vinylidene fluoride and acrylic monomer, copolymer of vinylidene fluoride and vinyl fluoride, terpolymer of tetrafluoroethylene, vinylidene fluoride and non-fluorinated monomer Examples thereof include fluoroterpolymers such as polymers, silicone resins, and the like, and two or more of them may be used in combination.

  Examples of the amino resin include urea-formaldehyde resin, melamine resin, benzoguanamine resin, urea resin, polyamide resin, and epoxy resin. Examples of the polyvinyl resin include acrylic resin, polymethyl methacrylate, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, and polyvinyl butyral. Examples of polystyrene resins include polystyrene and styrene-acrylic copolymers. Examples of the halogenated olefin resin include polyvinyl chloride. Examples of the polyester-based resin include polyethylene terephthalate and polybutylene terephthalate.

  Moreover, a resin layer may contain conductive powder etc. as needed. Examples of the conductive powder material include metals, carbon black, titanium oxide, tin oxide, and zinc oxide. The conductive powder preferably has an average particle size of 1 μm or less. When the average particle size exceeds 1 μm, it may be difficult to control the electric resistance. The resin layer is formed by, for example, preparing a coating solution by dissolving a silicone resin or the like in a solvent, and then applying the coating solution to the surface of the core material by a known coating method, followed by drying and baking. Can do. Examples of the application method include a dipping method, a spray method, and a brush coating method. Examples of the solvent include toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, celsol butyl acetate and the like. Furthermore, the baking method may be either an external heating method or an internal heating method, for example, a method using a fixed electric furnace, a fluid electric furnace, a rotary electric furnace, a burner furnace, or the like, or using a microwave. Methods and the like.

  The content of the resin layer in the carrier is preferably 0.01 to 5.0% by weight. If this content is less than 0.01% by weight, a uniform resin layer may not be formed on the surface of the core material. If it exceeds 5.0% by weight, the resin layer becomes too thick and the carriers are combined. Granulation may occur and a uniform carrier may not be obtained.

  The developer of the present invention can be suitably used for image formation by various known electrophotographic methods such as a magnetic one-component development method, a non-magnetic one-component development method, and a two-component development method.

  The developer container of the present invention contains the developer of the present invention, but the container is not particularly limited and can be appropriately selected from known ones, but has a container body and a cap. Etc. In addition, the size, shape, structure, material, etc. of the container body are not particularly limited, but the shape is preferably cylindrical, etc., spiral irregularities are formed on the inner peripheral surface, and by rotating, It is particularly preferable that the developer as the contents can move to the discharge port side, and that some or all of the spiral irregularities have a bellows function. Furthermore, the material is not particularly limited, but is preferably one having good dimensional accuracy. For example, polyester resin, polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, polyacrylic acid, polycarbonate resin, ABS resin, Examples thereof include resin materials such as polyacetal resin.

  Since the developer container is easy to store and transport and has excellent handleability, the developer container can be detachably attached to a process cartridge, an image forming apparatus, etc., which will be described later, and used for replenishing the developer.

[Full-color image forming method]
The full color image forming method of the present invention comprises a charging step of charging an electrophotographic photosensitive member with a charging unit, an exposure step of forming an electrostatic latent image on the charged electrophotographic photosensitive member with an exposing unit, and the electrostatic A developing step of forming a toner image on the electrophotographic photosensitive member on which the latent image is formed by a developing unit including toner, and a toner image formed on the electrophotographic photosensitive member is transferred onto the intermediate transfer member by a primary transfer unit. A primary transfer step, a secondary transfer step of transferring a toner image transferred onto the intermediate transfer member onto a recording material by a secondary transfer means, and heat and pressure fixing of the toner image transferred onto the recording material. A fixing step of fixing on a recording material by a fixing means including a member, and cleaning of residual toner adhering to the surface of the electrophotographic photosensitive member having the toner image transferred onto the intermediate transfer member by the primary transfer means. And a cleaning step of cleaning the stage. The toner used in the development process is a toner manufactured by the above-described manufacturing method of the present invention. In the full color image forming method of the present invention, in the secondary transfer step, the linear velocity of transfer of the toner image to the recording material is 300 to 1000 mm / sec, and the transfer time at the nip portion of the secondary transfer means is 0.5. It is preferable to set it to -20 msec. The full color image forming method of the present invention preferably employs a tandem electrophotographic image forming process.

(Charging process)
As the charging device used in the image forming method of the present invention, for example, the contact type charging device shown in FIGS. 1 and 2 can be used.

<Roller type charging device>
FIG. 1 shows a schematic configuration of an example of a roller charging device (500) which is a kind of contact charging device. A photosensitive member (505) as an image bearing member, which is a member to be charged, is driven to rotate at a predetermined speed (process speed) in the direction of the arrow. The charging roller (501), which is a charging member brought into contact with the photosensitive member (505), has a core metal (502) and a conductive rubber layer (503) formed on the roller concentrically and integrally on the outer periphery of the core metal (502). The basic structure is such that both ends of the core metal are held freely rotating by a bearing member (not shown), and are pressed against the photosensitive drum with a predetermined pressure by a pressing means (not shown). The roller (501) rotates following the rotational drive of the photoreceptor (505). The charging roller (501) is formed to a diameter of 16 mm by coating a medium resistance conductive rubber layer (503) of about 100,000 Ω · cm on a core metal having a diameter of 9 mm. The cored bar (502) of the charging roller (501) and the illustrated power source (504) are electrically connected, and a predetermined bias is applied to the charging roller (501) by the power source (504). As a result, the peripheral surface of the photoconductor (505) is uniformly charged to a predetermined polarity and potential.

<Fur brush type charging device>
The shape of the charging device used in the present invention may take any form, such as a magnetic brush type charging device or a fur brush type charging device, in addition to the roller type charging device, according to the specifications and form of the electrophotographic apparatus. Can be selected. When a magnetic brush charging device is used, the magnetic brush is composed of various ferrite particles such as Zn-Cu ferrite as a charging member, a non-magnetic conductive sleeve for supporting the charging member, and a magnet roll included therein. The In addition, when using a fur brush type charging device, for example, as a material of the fur brush, a fur treated with carbon, copper sulfide, metal, and metal oxide is used, and this is used as a metal or other conductive treated core. A charging device is formed by winding or sticking on gold.

  FIG. 2 shows a schematic configuration of an example of a contact-type brush charging device (510). A photoconductor (515) as an image carrier as a member to be charged is driven to rotate at a predetermined speed (process speed) in the direction of the arrow. A fur brush roller (511) constituted by a fur brush is brought into contact with the photoconductor (515) with a predetermined nip width with a predetermined pressing force against the elasticity of the brush portion (513).

  The fur brush roller (511) as a contact charging device in this example is composed of a metal cored bar (512) having a diameter of 6 mm which also serves as an electrode, and a conductive rayon fiber REC manufactured by Unitika Ltd. as a brush part (513). A tape with -B piled is wound spirally into a roll brush with an outer diameter of 14 mm and a longitudinal length of 250 mm. The brush of the brush portion (513) has a density of 300 denier / 50 filaments and 155 brushes per square millimeter. This roll brush was inserted into a pipe having an inner diameter of 12 mm while rotating in one direction, and the brush and the pipe were set to be concentric, and left in a high-temperature and high-humidity atmosphere to bend and bevel.

  The resistance value of the fur brush roller (511) is 1 × 10E5Ω at an applied voltage of 100V. This resistance value was converted from the current that flows when a fur brush roller is brought into contact with a metal drum having a diameter of φ30 mm with a nip width of 3 mm and a voltage of 100 V is applied. The resistance value of the brush-type charging device (510) is such that even when a low-voltage defective portion such as a pinhole is generated on the photosensitive member (515) to be charged, an excessive leak current flows into this portion. 10E4Ω or more is necessary to prevent an image defect in which the nip portion is poorly charged, and 10E7Ω or less is necessary to sufficiently inject the charge onto the surface of the photoreceptor (515).

  As the material of the brush, in addition to REC-B manufactured by Unitika Ltd., REC-C, REC-M1, REC-M10, SA-7 manufactured by Toray Industries, Inc., manufactured by Nippon Kashiwa Co., Ltd. Possible examples include Sanderlon, Kanebo Beltron, Kuraray Co., Ltd., Krabobo, carbon dispersion in rayon, Mitsubishi Rayon Co., Ltd. global. One brush is 3 to 10 denier, and preferably has a density of 10 to 100 filaments / bundle and 80 to 600 brushes / mm. The hair foot is preferably 1 to 10 mm.

  The fur brush roller (511) is rotationally driven at a predetermined peripheral speed (surface speed) in a direction (counter) opposite to the rotation direction of the photoconductor (515), and contacts the photoconductor surface with a speed difference. A predetermined charging voltage is applied to the brush roller (511) from the power source (514), so that the surface of the rotating photosensitive member is uniformly contact-charged to a predetermined polarity and potential.

  In this example, the contact charging of the photoreceptor (515) by the fur brush roller (511) is performed by direct injection charging, and the surface of the rotating photoreceptor is almost equal to the applied charging voltage to the fur brush roller (511). Charged to potential.

  In addition to the fur brush roller (511), the charging member used in the present invention may take any form such as a charging roller or a fur brush, and can be selected according to the specifications and form of the electrophotographic apparatus. is there. When a charging roller is used, it is generally used by coating a medium resistance rubber layer of about 100,000 Ω · cm on a cored bar. In the case of using a magnetic brush, the magnetic brush is composed of various ferrite particles such as Zn—Cu ferrite as a charging member, a non-magnetic conductive sleeve for supporting it, and a magnet roll included therein.

<Magnetic brush type charging device>
FIG. 2 is also a diagram showing a schematic configuration of an example of a magnetic brush type charging device. A photoreceptor (515) as a charged body and an image carrier is driven to rotate at a predetermined speed (process speed) in the direction of the arrow. A brush roller (511) constituted by a magnetic brush is brought into contact with the photoreceptor (515) with a predetermined nip width with a predetermined pressing force against the elasticity of the brush portion (513).

  As a magnetic brush as a contact charging member in this example, Zn—Cu ferrite particles having an average particle diameter of 25 μm and Zn—Cu ferrite particles having an average particle diameter of 10 μm are mixed at a weight ratio of 1: 0.05, Magnetic particles obtained by coating ferrite particles having an average particle diameter of 25 μm and having a peak at each average particle diameter position with a medium resistance resin layer were used. The contact charging member is composed of the coated magnetic particles prepared above, a nonmagnetic conductive sleeve for supporting the coated magnetic particles, and a magnet roll included therein, and the coated magnetic particles are formed on the sleeve with a thickness. Coating was performed at 1 mm to form a charging nip having a width of about 5 mm between the photosensitive member and the photosensitive member. The gap between the magnetic particle holding sleeve and the photosensitive member was about 500 μm. Further, the magnet roll is rotated so that the sleeve surface rubs in the opposite direction at twice as fast as the peripheral speed of the surface of the photoconductor, and the photoconductor and the magnetic brush are in uniform contact with each other. I did it.

(Development process)
In developing the latent image on the photoreceptor in the present invention, it is preferable to apply an alternating electric field. In the developing device (600) shown in FIG. 3, during development, a vibration bias voltage in which an AC voltage is superimposed on a DC voltage is applied to the developing sleeve (601) as a developing bias by a power source (602). The background portion potential and the image portion potential are located between the maximum value and the minimum value of the vibration bias potential. As a result, an alternating electric field whose direction changes alternately is formed in the developing portion (603). In this alternating electric field, the developer toner and the carrier vibrate vigorously, and the toner (605) flies to the photosensitive member (604) by shaking off the electrostatic binding force to the developing sleeve (601) and the carrier. It adheres corresponding to the latent image. The toner (605) is a toner manufactured by the above-described manufacturing method of the present invention.

  The difference (maximum peak voltage) between the maximum value and the minimum value of the vibration bias voltage is preferably 0.5 to 5 kV, and the frequency is preferably 1 to 10 kHz. As the waveform of the vibration bias voltage, a rectangular wave, a sine wave, a triangular wave, or the like can be used. As described above, the DC voltage component of the vibration bias is a value between the background part potential and the image part potential, but the value closer to the background part potential than the image part potential is more likely to cover the background part potential region. This is preferable for preventing toner adhesion.

  When the vibration bias voltage waveform is a rectangular wave, the duty ratio is preferably 50% or less. Here, the duty ratio is a ratio of time during which the toner is directed to the photosensitive member during one period of the vibration bias. By doing so, the difference between the peak value at which the toner is directed to the photoreceptor and the time average value of the bias can be increased, so that the movement of the toner is further activated and the potential of the latent image surface is increased. It can adhere to the distribution and improve the roughness and resolution. In addition, since the difference between the peak value of the carrier having a charge opposite to that of the toner and the time average value of the bias toward the photosensitive member can be reduced, the movement of the carrier is reduced, and the background portion of the latent image is reduced. The probability of carriers adhering to the substrate can be greatly reduced.

(Fixing device)
As the fixing device used in the image forming method of the present invention, for example, a charging device shown in FIG. 4 can be used. The fixing device shown in FIG. 4 includes a heating roller (710) heated by electromagnetic induction of an induction heating means (760), and a fixing roller (720) (opposite rotating body) arranged in parallel with the heating roller (710). And an endless belt that is stretched between the heating roller (710) and the fixing roller (720), is heated by the heating roller (710), and rotates in the direction of arrow A by at least one of these rollers rotating. A fixing belt (heat-resistant belt, toner heating medium) (730) and a pressure that is pressed against the fixing roller (720) via the fixing belt (730) and rotates in the forward direction with respect to the fixing belt (730). It is comprised from a roller (740) (pressure rotary body).

  The heating roller (710) is made of, for example, a hollow cylindrical magnetic metal member such as iron, cobalt, nickel, or an alloy of these metals, and has an outer diameter of, for example, 20 to 40 mm and a wall thickness of, for example, 0.3 to 1.0 mm. It has a low heat capacity and quick temperature rise.

  The fixing roller (720) (opposite rotating body) is made of, for example, a metal core (721) made of stainless steel or the like and a heat-resistant silicone rubber that is solid or foamed and covered with the core (721). It consists of a member (722). In order to form a contact portion having a predetermined width between the pressure roller (740) and the fixing roller (720) by the pressing force from the pressure roller (740), the outer shape is set to about 20 to 40 mm. 710). The elastic member (722) has a thickness of about 4 to 6 mm. With this configuration, since the heat capacity of the heating roller (710) is smaller than the heat capacity of the fixing roller (720), the heating roller (710) is rapidly heated and the warm-up time is shortened.

  The fixing belt (730) stretched between the heating roller (710) and the fixing roller (720) is heated at the contact portion (W1) with the heating roller (710) heated by the induction heating means (760). . Then, the inner surface of the fixing belt (730) is continuously heated by the rotation of the heating roller (710) and the fixing roller (720). As a result, the entire belt is heated. In the figure, reference numeral (742) denotes an elastic member, and reference numeral (750) denotes a temperature detection member.

FIG. 5 shows a layer structure of the fixing belt (730). The belt (730) has the following four layers from the inner layer to the surface layer, and can be configured as follows.
-Base (731): Resin layer such as polyimide (PI) resin-Heat generation layer (732): Conductive material layer such as Ni, Ag, SUS-Intermediate layer (733): Elastic layer for uniform fixing-Release layer (734): Resin layer such as fluorine resin material for releasing effect and oil-less

  The thickness of the release layer (734) is preferably about 10 μm to 300 μm, particularly about 200 μm. In this way, in the fixing device (700) as shown in FIG. 4, the toner image (T) formed on the recording material (770) is sufficiently wrapped by the surface layer portion of the fixing belt (730). The image (T) can be heated and melted uniformly. The thickness of the release layer (734), that is, the surface release layer, needs to be at least 10 μm in order to ensure wear resistance over time. Further, when the thickness of the release layer (734) is larger than 300 μm, the heat capacity of the fixing belt (730) is increased and the time required for warm-up is increased. Further, the surface temperature of the fixing belt (730) is hardly lowered in the toner image fixing step, and the effect of aggregating the melted toner at the fixing portion outlet cannot be obtained, and the releasability of the fixing belt (730) is lowered. The toner of the toner image (T) adheres to the fixing belt (730), and so-called hot offset occurs. The heat generating layer (732) made of the above metal may be used as the base of the fixing belt (730), but the heat resistance of fluorine resin, polyimide resin, polyamide resin, polyamideimide resin, PEEK resin, PES resin, PPS resin, etc. A resin layer having properties may be used.

  The pressure roller (740) includes, for example, a metal core (741) made of a metal cylindrical member having a high thermal conductivity such as copper or aluminum, and heat resistance and toner separation provided on the surface of the metal core (741). It is comprised from the elastic member (742) with high moldability. In addition to the above metal, SUS may be used for the core metal (741). The pressure roller (740) presses the fixing roller (720) via the fixing belt (730) to form a fixing nip (N). In this embodiment, the pressure roller (740) By making the hardness harder than that of the fixing roller (720), the pressure roller (740) bites into the fixing roller (720) (and the fixing belt (730)), and by this biting, the recording material (770) becomes. The recording material (770) is easily separated from the surface of the fixing belt (730) because it follows the circumferential shape of the surface of the pressure roller (740). The outer diameter of the pressure roller (740) is about 20 to 40 mm, which is the same as that of the fixing roller (720), but the wall pressure is about 0.5 to 2.0 mm and is thinner than the fixing roller (720).

  As shown in FIG. 4, the induction heating means (760) for heating the heating roller (710) by electromagnetic induction includes an excitation coil (761) as a magnetic field generation means and a coil around which the excitation coil (761) is wound. And a guide plate (762). The coil guide plate (762) has a semi-cylindrical shape disposed close to the outer peripheral surface of the heating roller (710), and the excitation coil (761) has a single long excitation coil wire as the coil guide plate (762). Along the axial direction of the heating roller (710). The excitation coil (761) has an oscillation circuit connected to a drive power supply (not shown) whose frequency is variable. On the outside of the exciting coil (761), a semi-cylindrical exciting coil core (763) made of a ferromagnetic material such as ferrite is fixed to the exciting coil core support member (764) and is disposed close to the exciting coil (761). Yes.

[Process cartridge]
The process cartridge of the present invention includes an electrophotographic photosensitive member, a charging unit that charges the electrophotographic photosensitive member, an exposure unit that forms an electrostatic latent image on the charged electrophotographic photosensitive member, and the electrophotographic photosensitive member. Developing means for converting the electrostatic latent image formed on the body into a toner image with toner, and transferring the toner image formed on the electrophotographic photosensitive member onto a recording material with or without an intermediate transfer member. A transfer unit; a fixing unit fixing step of fixing the toner image transferred onto the recording material onto the recording material by a heat and pressure fixing member; and the toner image is transferred onto the intermediate transfer member or the recording material by the transfer unit. Among the units in the image forming apparatus provided with the cleaning unit for cleaning the transfer residual toner adhering to the surface of the subsequent electrophotographic photosensitive member, the upper part including at least the electrophotographic photosensitive member and the developing unit. It is obtained by detachable to the image forming apparatus main body integrally supported means. The developing means includes a toner manufactured by the above-described manufacturing method of the present invention. As the developing unit and the charging unit, the above-described developing device and charging device can be preferably used.

  An example of the process cartridge of the present invention is shown in FIG. The process cartridge (800) shown in FIG. 6 includes a photoreceptor (801), a charging unit (802), a developing unit (803), and a cleaning unit (806). The operation of the process cartridge (800) will be described. The photosensitive member (801) is rotationally driven at a predetermined peripheral speed. In the rotating process, the photosensitive member (801) is uniformly charged at a predetermined positive or negative potential on its peripheral surface by the charging means (802), and then from an image exposure means (not shown) such as slit exposure or laser beam scanning exposure. In this way, an electrostatic latent image is sequentially formed on the peripheral surface of the photoreceptor (801), and the formed electrostatic latent image is then converted into a toner image by the developing means (803) and developed. The toner image is sequentially transferred from the paper feeding unit to the recording material fed between the photosensitive member (801) and a transfer unit (not shown) in synchronization with the rotation of the photosensitive member (801) by the transfer unit. . The recording material that has undergone image transfer is separated from the surface of the photosensitive member, introduced into an image fixing means (not shown), and fixed on the image, and printed out as a copy (copy). The surface of the photoconductor (801) after the image transfer is cleaned by removing the transfer residual toner by the cleaning means (806), and after being further discharged, it is repeatedly used for image formation. In the figure, reference numeral (804) denotes toner, and reference numeral (805) denotes a developing roller.

(Full color image forming method)
As the full-color image forming apparatus used in the full-color image forming method of the present invention, for example, the tandem image forming apparatus (100) shown in FIGS. 7 and 8 can be used. In FIG. 7, an image forming apparatus (100) includes an image writing unit (120Bk, 120C, 120M, 120Y), an image forming unit (130Bk, 130C, 130M, 130Y), a feed for performing color image formation by electrophotography. It is mainly composed of a paper portion (140). Based on the image signal, image processing is performed by an image processing unit (not shown) and converted into black (Bk), cyan (C), magenta (M), and yellow (Y) color signals for image formation, It transmits to an image writing part (120Bk, 120C, 120M, 120Y). The image writing unit (120Bk, 120C, 120M, 120Y) is a laser scanning optical system including, for example, a laser light source, a deflector such as a rotary polygon mirror, a scanning imaging optical system, and a mirror group (none of which are shown). There are four writing optical paths corresponding to the respective color signals, and image writing corresponding to the respective color signals is performed in the image forming units (130Bk, 130C, 130M, and 130Y).

  The image forming unit (130Bk, 130C, 130M, and 130Y) includes photoconductors (210Bk, 210C, 210M, and 210Y) for black, cyan, magenta, and yellow, and the photoconductors (210Bk, 210C, and 210Y) for these colors. 210M and 210Y) are usually OPC photoreceptors. Around each photoconductor (210Bk, 210C, 210M, 210Y), there is a charging device (215Bk, 215C, 215M, 215Y), an exposure unit for laser light from the image writing unit (120Bk, 120C, 120M, 120Y). , Developing devices for each color (200Bk, 200C, 200M, 200Y), primary transfer devices (230Bk, 230C, 230M, 230Y), cleaning devices (300Bk, 300C, 300M, 300Y), static eliminators (not shown), etc. Is arranged. The developing device (200Bk, 200C, 200M, 200Y) uses a two-component magnetic brush developing system. An intermediate transfer belt (220) is interposed between each photoconductor (210Bk, 210C, 210M, 210Y) and the primary transfer device (230Bk, 230C, 230M, 230Y), and this intermediate transfer belt (220). The toner images of the respective colors are sequentially transferred from the respective photoconductors so as to carry the toner images on the respective photoconductors.

  In some cases, a pre-transfer charger (502) as pre-transfer charging means is disposed outside the intermediate transfer belt (220) at a position after passing the primary transfer position of the final color and before passing the secondary transfer position. It is preferable. The pre-transfer charger (502) transfers the toner image before transferring the toner image on the intermediate transfer belt (220) transferred to the photosensitive member (210) to the transfer paper as a recording material. The toner image is uniformly charged to the same polarity as the toner image.

  The toner image on the intermediate transfer belt (220) transferred from each photoconductor (210Bk, 210C, 210M, 210Y) includes a halftone portion and a solid portion, or includes portions having different amounts of toner overlap. Therefore, the charge amount may vary. Further, when the discharge amount generated in the gap adjacent to the downstream side of the primary transfer portion in the movement direction of the intermediate transfer belt causes variation in charge amount in the toner image on the intermediate transfer belt (220) after the primary transfer. There is also. Such variation in the charge amount in the same toner image lowers the transfer margin in the secondary transfer portion that transfers the toner image on the intermediate transfer belt (220) onto the transfer paper. Therefore, the toner image before being transferred to the transfer paper by the pre-transfer charger is uniformly charged to the same polarity as the toner image, thereby eliminating the variation in the charge amount in the same toner image and the transfer margin in the secondary transfer portion. Has improved. In the figure, reference numerals (250Bk, 250C, 250M, 250Y) denote toner transfer pipes of the respective colors, reference numeral (260) denotes an intermediate transfer belt cleaning device, reference numeral (500) denotes a transfer belt, and reference numeral (502) denotes a transfer charger. , (600) is a secondary transfer roller, (10Y, 10C, 10M, 10K) is each photoconductor, (14) is a first support roller, and (15) is a second support roller. Reference numeral (16) indicates a third support roller, reference numeral (130) indicates a document table, reference numeral (40) indicates a photosensitive member, reference numeral (142) indicates a paper feed roller, and reference numeral (143) indicates a paper bank. , (144) is a paper feed cassette, (145) is a separation roller, (146) is a paper feed path, (147) is a transport roller, and (148) is a paper feed path. (52) is the separation roller, Reference numeral (58) denotes a paper feed roller, reference numeral (62) denotes a primary transfer device, reference numeral (100) denotes an image forming apparatus, reference numeral (110) denotes a copying apparatus main body, and reference numeral (110) denotes an image forming apparatus main body. Reference numeral (120) denotes each color image forming unit, reference numeral (130) denotes a document placement table, reference numeral (145) denotes a separation roller, reference numeral (146) denotes a paper feed path, and reference numeral (147) denotes a conveyance roller. Reference numeral (148) denotes a paper feed path.

  As described above, according to this image forming method, the toner image on the intermediate transfer belt (220) transferred from each photoconductor (210Bk, 210C, 210M, 210Y) is uniformly charged by the pre-transfer charger (502). Even if there is a variation in the charge amount in the toner image on the intermediate transfer belt (220), the transfer characteristics in the secondary transfer portion are made almost constant across the portions of the toner image on the intermediate transfer belt (220). Can do. Therefore, it is possible to suppress a decrease in transfer margin when transferring to transfer paper and to stably transfer a toner image.

  In this image forming method, the amount of charge charged by the pre-transfer charger varies depending on the moving speed of the intermediate transfer belt (220) that is the object to be charged. For example, if the moving speed of the intermediate transfer belt (220) is slow, the time for the same portion of the toner image on the intermediate transfer belt (220) to pass through the charging area by the pre-transfer charger becomes long, and the charge amount increases. Conversely, when the moving speed of the intermediate transfer belt (220) is fast, the charge amount of the toner image on the intermediate transfer belt (220) becomes small. Therefore, when the moving speed of the intermediate transfer belt (220) changes while the toner image on the intermediate transfer belt (220) passes through the charging position by the pre-transfer charger, the intermediate transfer belt (220 It is desirable to control the pre-transfer charger so that the charge amount with respect to the toner image does not change in the middle according to the movement speed of ().

  Conductive rollers (241), (242), and (243) are provided between the primary transfer devices (230Bk, 230C, 230M, and 230Y). After the transfer paper is fed from the paper feed unit (140), it is carried on the transfer belt (500) via the registration roller pair (160), and the intermediate transfer belt (220) and the transfer belt (500) are in contact with each other. The toner image on the intermediate transfer belt (220) is transferred to the transfer paper by the secondary transfer roller (600), and a color image is formed.

  Then, the transfer paper after image formation is conveyed to the fixing device (150) by the secondary transfer belt (180), and the image is fixed to obtain a color image. The toner on the intermediate transfer belt (220) remaining without being transferred is removed from the belt by the intermediate transfer belt cleaning device (260).

  Since the toner polarity on the intermediate transfer belt (220) before transfer onto the transfer paper is the same negative polarity as that during development, a positive transfer bias voltage is applied to the secondary transfer roller (170), and the toner is transferred. It is transferred onto paper. The nip pressure at this portion affects the transfer property and greatly affects the fixability. Further, the toner on the intermediate transfer belt (220) remaining without being transferred is discharged and charged to the positive polarity side and charged from 0 to the positive side at the moment when the transfer paper and the intermediate transfer belt (220) are separated. Note that the toner image formed when the transfer paper is jammed or in the non-image area is not affected by the secondary transfer, and of course remains in the negative polarity.

  The thickness of the photoreceptor layer is 30 μm, the beam spot diameter of the optical system is 50 × 60 μm, and the light quantity is 0.47 Mw. The developing process is carried out with the charging (exposure side) potential V0 of the photoconductor (black) (210Bk) set to -700V, the post-exposure potential VL set to -120V, and the developing bias voltage set to -470V, ie, the developing potential 350V. The visible image of the toner (black) formed on the photoconductor (black) (210Bk) is then transferred (intermediate transfer belt and transfer paper) and completed as an image through a fixing process. First, all colors are transferred from the primary transfer device (230Bk, 230C, 230M, 230Y) to the intermediate transfer belt (220), and then applied to the transfer paper by applying a bias to another secondary transfer roller (170). Transcribed.

  Next, the photoconductor cleaning device will be described in detail. In FIG. 7, each developing device (200Bk, 200C, 200M, 200Y) and each cleaning device (300Bk, 300C, 300M, 300Y) are connected to each other by a toner transfer pipe (250Bk, 250C, 250M, 250Y). (Dashed line in FIG. 7). Each toner transfer pipe (250Bk, 250C, 250M, 250Y) contains a screw (not shown), and the toner collected by each cleaning device (300Bk, 300C, 300M, 300Y) Each developing device (200Bk, 200C, 200M, 200Y) is transferred.

  In the conventional direct transfer method using the combination of the four photosensitive drums and the belt conveyance, paper dust adheres when the photoreceptor and the transfer paper come into contact with each other, and the paper dust is contained when the toner is collected. The image was deteriorated such as toner missing and could not be used. Furthermore, in the conventional system combining a single photoconductor drum and intermediate transfer, the use of an intermediate transfer member eliminates paper dust adhesion to the photoconductor during transfer paper transfer, but recycling of residual toner on the photoconductor In practice, it is practically impossible to separate the mixed color toners. There is also a proposal to use a mixed color toner as a black toner, but even if all the colors are mixed, it does not become black, and the color changes depending on the print mode. Therefore, it is impossible to recycle the toner with one photoconductor configuration.

  On the other hand, the full-color molding apparatus uses an intermediate transfer belt (220), so that paper dust is less mixed and also prevents paper dust from adhering to the intermediate transfer belt (220) during paper transfer. Is done. Since each photoconductor (210Bk, 210C, 210M, 210Y) uses independent color toner, it is not necessary to contact or separate each photoconductor cleaning device (300Bk, 300C, 300M, 300Y), and only the toner is reliably collected. can do.

  The positively charged toner remaining on the intermediate transfer belt (220) is cleaned by a conductive fur brush (262) to which a negative voltage is applied. The method of applying a voltage to the conductive fur brush (262) is exactly the same as that of the conductive fur brush (261) except for the polarity. The toner remaining without being transferred is also almost cleaned by the two conductive fur brushes (261) and (262). Here, toner, paper powder, talc, and the like remaining without being cleaned by the conductive fur brush (262) are negatively charged by the negative voltage of the conductive fur brush (262). The next black primary transfer is a transfer using a positive voltage, and negatively charged toner or the like is attracted to the intermediate transfer belt (220) side, so that the transfer to the photoconductor (black) (210Bk) side can be prevented.

  Next, the intermediate transfer belt (220) used in this image forming apparatus will be described. As described above, the intermediate transfer belt is preferably a single resin layer, but may have an elastic layer or a surface layer as necessary.

  As the resin material constituting the resin layer, polycarbonate, fluororesin (ETFE, PVDF), polystyrene, chloropolystyrene, poly-α-methylstyrene, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene -Vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer) Styrene-octyl acrylate copolymer and styrene-phenyl acrylate copolymer), styrene-methacrylic acid ester copolymer (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene- (Methacrylic acid phenyl copolymer, etc.), styrene -Styrenic resins (monopolymer or copolymer containing styrene or a styrene-substituted product) such as methyl α-chloroacrylate copolymer, styrene-acrylonitrile-acrylic acid ester copolymer, methyl methacrylate resin, methacrylic acid Butyl resin, ethyl acrylate resin, butyl acrylate resin, modified acrylic resin (silicone modified acrylic resin, vinyl chloride resin modified acrylic resin, acrylic / urethane resin, etc.), vinyl chloride resin, styrene-vinyl acetate copolymer, vinyl chloride -Vinyl acetate copolymer, rosin modified maleic acid resin, phenol resin, epoxy resin, polyester resin, polyester polyurethane resin, polyethylene, polypropylene, polybutadiene, polyvinylidene chloride, ionomer resin, polyurethane resin, silicone resin , Ketone resin, ethylene - ethyl acrylate copolymer, may be used xylene resin and polyvinyl butyral resin, polyamide resin, one kind or two kinds or more selected from the group consisting of modified polyphenylene oxide resin. However, it is a matter of course that the material is not limited to the above materials.

  Examples of the elastic material (elastic material rubber, elastomer) constituting the elastic layer include butyl rubber, fluorine-based rubber, acrylic rubber, EPDM, NBR, acrylonitrile-butadiene-styrene rubber natural rubber, isoprene rubber, styrene-butadiene rubber, Butadiene rubber, ethylene-propylene rubber, ethylene-propylene terpolymer, chloroprene rubber, chlorosulfonated polyethylene, chlorinated polyethylene, urethane rubber, syndiotactic 1,2-polybutadiene, epichlorohydrin rubber, ricone rubber, fluororubber, Polysulfide rubber, polynorbornene rubber, hydrogenated nitrile rubber, thermoplastic elastomer (eg polystyrene, polyolefin, polyvinyl chloride, polyurethane, polyamide, polyurea, polyester) It is possible to use one kind or two kinds or more selected from the group consisting of fluorocarbon resin) or the like. However, it is a matter of course that the material is not limited to the above materials.

  The material for the surface layer is not particularly limited, but a material that reduces the adhesive force of the toner to the surface of the intermediate transfer belt and increases the secondary transfer property is required. For example, materials that use one or more of polyurethane, polyester, epoxy resin, etc. to reduce surface energy and increase lubricity, such as fluorine resin, fluorine compound, fluorocarbon, titanium dioxide, silicon carbide, etc. One kind or two or more kinds of powders and particles or particles having different particle diameters can be dispersed and used. Further, it is also possible to use a material having a surface energy reduced by forming a fluorine-rich layer on the surface by heat treatment, such as a fluorine-based rubber material.

  A resistance value adjusting conductive agent is added to the resin layer and the elastic layer. The conductive agent for adjusting the resistance value is not particularly limited. For example, carbon black, graphite, metal powder such as aluminum and nickel, tin oxide, titanium oxide, antimony oxide, indium oxide, potassium titanate, antimony oxide-tin oxide Conductive metal oxides such as composite oxide (ATO) and indium oxide-tin oxide composite oxide (ITO), and conductive metal oxide covered with insulating fine particles such as barium sulfate, magnesium silicate, and calcium carbonate. It may be a thing. Of course, the conductive agent is not limited thereto.

  FIG. 8 shows another example of an image forming apparatus used in the image forming method of the present invention, which is a copying apparatus (100) provided with a tandem indirect transfer type electrophotographic image forming apparatus. In FIG. 8, (101) is a copying apparatus main body, (200) is a paper feed table on which it is placed, (300) is a scanner mounted on the copying apparatus main body (101), and (400) is an automatic document feeder mounted thereon. Device (ADF). The copying machine main body (101) is provided with an endless belt-shaped intermediate transfer member (10) in the center.

  Then, as shown in FIG. 8, in this example, the three support rollers (14), (15), and (16) are hung to enable rotation and conveyance in the clockwise direction in the figure. In this illustrated example, an intermediate transfer body cleaning device (17) for removing residual toner remaining on the intermediate transfer body (10) after image transfer is provided on the left of the second support roller (15) among the three. Further, among the three, the intermediate transfer member (10) stretched between the first support roller (14) and the second support roller (15) has yellow, cyan and magenta along the transport direction. The four black image forming means (18) are arranged side by side to constitute a tandem image forming apparatus (20).

  An exposure device (21) is further provided on the tandem image forming apparatus (20) as shown in FIG. On the other hand, a secondary transfer device (22) is provided on the side opposite to the tandem image forming device (20) with the intermediate transfer member (10) interposed therebetween. In the illustrated example, the secondary transfer device (22) includes a secondary transfer belt (24), which is an endless belt, spanned between two rollers (23), and the second transfer device (22) passes through an intermediate transfer member (10). 3 is pressed against the support roller (16), and the image on the intermediate transfer body (10) is transferred to the sheet. Next to the secondary transfer device (22), a fixing device (25) for fixing the transferred image on the sheet is provided. The fixing device (25) is configured by pressing a pressure roller (27) against a fixing belt (26) which is an endless belt. The secondary transfer device (22) described above is also provided with a sheet transport function for transporting the image-transferred sheet to the fixing device (25). Of course, as the secondary transfer device (22), a transfer roller or a non-contact charger may be arranged. In such a case, it is difficult to provide this sheet conveying function together. In the illustrated example, a sheet is placed under such a secondary transfer device (22) and a fixing device (25) so as to record an image on both sides of the sheet in parallel with the tandem image forming device (20). A sheet inverting device (28) for inverting is provided.

  Now, when making a copy using this color electrophotographic apparatus, the document is set on the document table (30) of the automatic document feeder (400). Alternatively, the automatic document feeder (400) is opened, a document is set on the contact glass (32) of the scanner (300), and the automatic document feeder (400) is closed and pressed by it.

  When a start switch (not shown) is pressed, when the document is set on the automatic document feeder (400), the document is transported and moved onto the contact glass (32), and then the other contact glass (32). When a document is set on the scanner, the scanner (300) is immediately driven to travel on the first traveling body (33) and the second traveling body (34). Then, the first traveling body (33) emits light from the light source, and the reflected light from the document surface is further reflected toward the second traveling body (34) and reflected by the mirror of the second traveling body (34). Then, the image is placed in the reading sensor (36) through the imaging lens (35) and the content of the original is read.

  When a start switch (not shown) is pressed, one of the support rollers (14), (15), and (16) is driven to rotate by the drive motor (not shown), and the other two support rollers are driven to rotate. The transfer body (10) is rotated and conveyed. At the same time, the individual image forming means (18) rotates the photoreceptor (40) to form monochrome images of black, yellow, magenta, and cyan on each photoreceptor (40). Then, along with the conveyance of the intermediate transfer member (10), these monochrome images are sequentially transferred to form a composite color image on the intermediate transfer member (10).

  On the other hand, when a start switch (not shown) is pressed, one of the paper feed rollers (42) of the paper feed table (200) is selectively rotated, and one of paper feed cassettes (44) provided in multiple stages in the paper bank (43). The sheet is fed out from the sheet, separated one by one by a separation roller (45), put into a sheet feeding path (46), and conveyed by a conveying roller (47) to a sheet feeding path (48) in the copying machine main body (100). Guide and stop against the registration roller (49).

  Alternatively, the sheet feeding roller (50) is rotated to feed out the sheets on the manual feed tray (51), separated one by one by the separation roller (52), and placed in the manual sheet feeding path (53). ) And stop. Then, the registration roller (49) is rotated in time with the composite color image on the intermediate transfer member (10), and the sheet is fed between the intermediate transfer member (10) and the secondary transfer device (22). The image is transferred by the next transfer device (22) and a color image is recorded on the sheet.

  The sheet after the image transfer is conveyed by the secondary transfer device (22) and sent to the fixing device (25). The fixing device (25) applies heat and pressure to fix the transferred image, and then the switching claw. It is switched at (55), discharged by the discharge roller (56), and stacked on the discharge tray (57). Alternatively, it is switched by the switching claw (55) and put into the sheet reversing device (28), where it is reversed and guided again to the transfer position, and an image is recorded also on the back surface, and then the paper discharge tray (56) is discharged by the discharge roller (56). 57) Drain up.

  On the other hand, the intermediate transfer member (10) after the image transfer is removed by the intermediate transfer member cleaning device (17) to remove residual toner remaining on the intermediate transfer member (10) after the image transfer, and the tandem image forming device (20). To prepare for image formation again. Here, the registration roller (49) is generally used while being grounded, but it is also possible to apply a bias for removing paper dust from the sheet.

  Examples of the present invention will be described below, but the present invention is not limited to the examples. As described above, the method for producing the toner of the present invention is not particularly limited. In the examples, the result of producing the toner using the dissolution suspension method, which is one of the underwater granulation methods, will be described. In addition, a part means a mass part.

-Synthesis of polyester resin A-
Into a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, 65 parts of 2-molar addition product of ethylene oxide of bisphenol A, 86 parts of 3-mole addition product of propion oxide of bisphenol A, 274 parts of terephthalic acid and 2 parts of dibutyltin oxide And allowed to react at 230 ° C. for 15 hours under normal pressure. Next, it was made to react under reduced pressure of 5-10 mmHg for 6 hours, and the polyester resin was synthesize | combined. The obtained polyester resin A has a number average molecular weight (Mn) of 2,300, a weight average molecular weight (Mw) of 8,000, a glass transition temperature (Tg) of 58 ° C., an acid value of 25 mgKOH / g, and a hydroxyl value of It was 35 mgKOH / g.

-Synthesis of styrene acrylic resin A-
In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, 300 parts of ethyl acetate, 185 parts of styrene, 115 parts of acrylic monomer and 5 parts of azobisisobutylnitrile were introduced, and the temperature was 65 ° C. (atmospheric pressure). ) For 8 hours. Next, 200 parts of methanol was added and stirred for 1 hour, and then the supernatant was removed and dried under reduced pressure to synthesize styrene-acrylic resin A. The obtained styrene acrylic resin A had Mw of 20,000 and Tg of 58 ° C.

-Synthesis of prepolymer (polymer capable of reacting with active hydrogen group-containing compound)-
In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, 682 parts by mass of bisphenol A ethylene oxide 2 mol adduct, 81 parts by mass of bisphenol A propylene oxide 2 mol adduct, 283 parts by mass of terephthalic acid, trimellitic anhydride 22 parts by mass and 2 parts by mass of dibutyltin oxide were charged and reacted at 230 ° C. for 8 hours under normal pressure. Subsequently, it was made to react under reduced pressure of 10-15mHg for 5 hours, and the intermediate polyester was synthesize | combined.

  The obtained intermediate polyester has a number average molecular weight (Mn) of 2,100, a weight average molecular weight (Mw) of 9,600, a glass transition temperature (Tg) of 55 ° C., an acid value of 0.5, and a hydroxyl value of 49.

  Next, 411 parts by mass of the intermediate polyester, 89 parts by mass of isophorone diisocyanate, and 500 parts by mass of ethyl acetate are charged in a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube, and reacted at 100 ° C. for 5 hours. Thus, a prepolymer (polymer capable of reacting with the active hydrogen group-containing compound) was synthesized.

  The free isocyanate content of the obtained prepolymer was 1.60% by mass, and the solid content concentration of the prepolymer (after standing at 150 ° C. for 45 minutes) was 50% by mass.

-Synthesis of ketimine (the active hydrogen group-containing compound)-
In a reaction vessel equipped with a stir bar and a thermometer, 30 parts by mass of isophoronediamine and 70 parts by mass of methyl ethyl ketone were charged and reacted at 50 ° C. for 5 hours to synthesize a ketimine compound (the active hydrogen group-containing compound). The amine value of the obtained ketimine compound (the active hydrogen machine-containing compound) was 423.

-Preparation of master batch-
1,000 parts of water, 540 parts of carbon black Printex 35 (manufactured by Degussa) having a DBP oil absorption of 42 mL / 100 g and a pH of 9.5, and 1,200 parts of polyester resin A, Henschel mixer (manufactured by Mitsui Mining) And mixed. Next, the obtained mixture was kneaded at 150 ° C. for 30 minutes using two rolls, then cooled by rolling, and pulverized with a pulverizer (manufactured by Hosokawa Micron Corporation) to prepare a master batch.

Example 1
In Example 1, toner was prepared by the following polymerization method.

-Preparation of aqueous medium-
An aqueous medium was prepared by mixing and stirring 306 parts of ion-exchanged water, 265 parts of a 10% by mass suspension of tricalcium phosphate, and 1.0 part of sodium dodecylbenzenesulfonate, and uniformly dissolving them.

-Measurement of critical micelle concentration-
The critical micelle concentration of the surfactant was measured by the following method. Using a surface tension meter Sigma (manufactured by KSV Instruments), analysis was performed using an analysis program in the Sigma system. Surfactant was added dropwise by 0.01 wt% with respect to the aqueous medium, and the interfacial tension after stirring and standing was measured. From the obtained surface tension curve, the surfactant concentration at which the interfacial tension did not decrease even when the surfactant was dropped was calculated as the critical micelle concentration. When the critical micelle concentration of sodium dodecylbenzenesulfonate with respect to the aqueous medium of Example 1 was measured with a surface tension meter Sigma, it was 0.05 wt% with respect to the weight of the aqueous medium.

-Adjustment of toner material liquid-
In a beaker, 70 parts of polyester resin A, 10 parts by mass of prepolymer and 100 parts of ethyl acetate were added and dissolved by stirring. As a release agent, 5 parts of paraffin wax (HNP-9, melting point 75 ° C., manufactured by Nippon Seiki Co., Ltd.), 2 parts of MEK-ST (Nissan Chemical Industry Co., Ltd.), and 10 parts of masterbatch were added. After 3 passes under the condition that the liquid feeding speed is 1 kg / hour, the peripheral speed of the disk is 6 m / second, and 80% by volume of zirconia beads having a particle diameter of 0.5 mm are filled, the ketimine 2.7 is used. A part by mass was added and dissolved to prepare a toner material solution.

―Preparation of emulsion or dispersion―
150 parts by mass of the aqueous medium phase is placed in a container, and stirred at a rotational speed of 12,000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). The mixture was added and mixed for 10 minutes to prepare an emulsified dispersion (emulsified slurry).

―Removal of organic solvent―
100 parts by mass of the emulsified slurry was charged into a Kolben equipped with a stirrer and a thermometer, and the solvent was removed at 30 ° C. for 12 hours while stirring at a stirring peripheral speed of 20 m / min.

-Washing-
After 100 parts by mass of the dispersion slurry was filtered under reduced pressure, 100 parts by mass of ion-exchanged water was added to the filter cake, mixed with a TK homomixer (10 minutes at a rotational speed of 12,000 rpm), and then filtered. To the obtained filter cake, 300 parts by mass of ion-exchanged water was added, mixed with a TK homomixer (10 minutes at 12,000 rpm), and then filtered twice. To the obtained filter cake, 20 parts by mass of a 10% by mass aqueous sodium hydroxide solution was added, mixed with a TK homomixer (30 minutes at 12,000 rpm), and then filtered under reduced pressure. To the obtained filter cake, 300 parts by mass of ion-exchanged water was added, mixed with a TK homomixer (at 12,000 rpm for 10 minutes), and then filtered. To the obtained filter cake, 300 parts by mass of ion-exchanged water was added, mixed with a TK homomixer (10 minutes at 12,000 rpm), and then filtered twice. Furthermore, 20 mass parts of 10 mass% hydrochloric acid was added to the obtained filter cake, mixed with a TK homomixer (at a rotation speed of 12,000 rpm for 10 minutes) and then filtered.

-Surfactant adjustment-
To the filter cake obtained by the above washing, 300 parts by mass of ion-exchanged water was added, and the electrical conductivity of the toner dispersion was measured by mixing with a TK homomixer (10 minutes at 12,000 rpm). The surfactant concentration of the toner dispersion was calculated from a calibration curve for surfactant concentration prepared in advance. From this value, ion-exchanged water was added so that the surfactant concentration was the target surfactant concentration of 0.05 wt%, and a toner dispersion was obtained.

―Surface treatment process―
The toner dispersion liquid adjusted to the predetermined surfactant concentration was heated for 10 hours at a heating temperature T1 = 55 ° C. in a water bath while mixing at 5000 rpm with a TK homomixer. Thereafter, the toner dispersion was cooled to 25 ° C. and filtered. Further, 300 parts by mass of ion-exchanged water was added to the obtained filter cake, mixed with a TK homomixer (10 minutes at 12,000 rpm), and then filtered.

―Dry―
The obtained final filter cake was dried with a circulating dryer at 45 ° C. for 48 hours, and sieved with a mesh of 75 μm to obtain toner base particles of Example 1.

―External treatment―
Further, with respect to 100 parts by weight of the toner base particles, 0.6 part by weight of hydrophobic silica having an average particle diameter of 100 nm, 1.0 part by weight of titanium oxide having an average particle diameter of 20 nm, and hydrophobic silica having an average particle diameter of 15 nm 0.8 parts of the fine powder was mixed with a Henschel mixer to obtain the toner of Example 1.

(Example 2)
A toner of Example 2 was prepared in the same manner as in Example 1 except that the heating temperature T1 in the surface treatment process of Example 1 was changed to 46 ° C.

(Example 3)
A toner of Example 2 was prepared in the same manner as in Example 1 except that the heating temperature T1 in the surface treatment process of Example 1 was changed to 64 ° C.

( Reference Example 1 )
The toner of Reference Example 1 was produced by the pulverization method as follows.
-Preparation of toner base particles-
After adding 80 parts by mass of polyester resin A, 5 parts of paraffin wax (HNP-9 melting point 75 ° C., manufactured by Nippon Seiki Co., Ltd.) and 10 parts of master batch, the mixture was sufficiently stirred and mixed in a Henschel mixer, and then at 130 ° C. using a roll mill. The mixture was heated and melted for 30 minutes, further cooled to room temperature, and the obtained kneaded material was coarsely pulverized to 200 to 400 μm with a hammer mill. Next, a finely pulverized apparatus that directly pulverizes the coarsely pulverized product against the impingement plate using a jet stream, and a finely pulverized powder obtained by the finely pulverized apparatus forms a swirl flow in the classification chamber, and Crushing and classification were performed using an IDS-2 type pulverizing and classifying apparatus (manufactured by Nippon Pneumatic Industry Co., Ltd.) integrally having an air classifier that was separated by centrifugation, and toner base particles were obtained after classification.

  The desired particle size distribution is measured with a Coulter counter, the supply amount of the object to be crushed, the pressure and flow rate of the pulverizing high-pressure air, the hair on the collision member for pulverization, and the air when the air in the classifier is sucked It can be adjusted by changing the inflow position, the inflow direction, the exhaust blower pressure, and the like.

-Adjustment of toner dispersion-
100 parts by mass of the obtained toner base particles, 5 parts by mass of sodium dodecylbenzenesulfonate, and 895 parts by mass of ion-exchanged water are added and mixed with a TK homomixer (at 12,000 rpm for 10 minutes) to disperse the toner. A liquid was obtained.

―Surface treatment process―
The toner dispersion obtained as described above was heated for 10 hours at a heating temperature T1 = 55 ° C. in a water bath while mixing at 5000 rpm with a TK homomixer. Thereafter, the toner dispersion was cooled to 25 ° C. and filtered. Further, 300 parts by mass of ion-exchanged water was added to the obtained filter cake, mixed with a TK homomixer (10 minutes at 12,000 rpm), and then filtered.

―Dry―
The obtained final filter cake was dried with a circulating dryer at 45 ° C. for 48 hours, and sieved with a mesh of 75 μm to obtain toner base particles of Reference Example 1 .

―External treatment―
Further, with respect to 100 parts by weight of the toner base particles, 0.6 part by weight of hydrophobic silica having an average particle diameter of 100 nm, 1.0 part by weight of titanium oxide having an average particle diameter of 20 nm, and hydrophobic silica having an average particle diameter of 15 nm 0.8 parts of the fine powder was mixed with a Henschel mixer to obtain the toner of Reference Example 1 .

( Reference Example 2 )
The toner of Reference Example 2 was prepared in the same manner except that the heating temperature T1 in the surface treatment step of Reference Example 1 was changed to 64 ° C.

(Example 4 )
The toner of Example 4 was prepared as follows.

-Preparation of aqueous medium-
An aqueous medium was prepared by mixing and stirring 306 parts of ion-exchanged water, 265 parts of a 10% by mass suspension of tricalcium phosphate, and 1.0 part of sodium dodecylbenzenesulfonate, and uniformly dissolving them.

―Measurement of critical micelle concentration―
The critical micelle concentration of the surfactant was measured by the following method. Using a surface tension meter Sigma (manufactured by KSV Instruments), analysis was performed using an analysis program in the Sigma system. Surfactant was added dropwise by 0.01 wt% with respect to the aqueous medium, and the interfacial tension after stirring and standing was measured. From the obtained surface tension curve, the surfactant concentration at which the interfacial tension did not decrease even when the surfactant was dropped was calculated as the critical micelle concentration. When the critical micelle concentration of sodium dodecylbenzenesulfonate with respect to the aqueous medium of Example 1 was measured with a surface tension meter Sigma, it was 0.05 wt% with respect to the weight of the aqueous medium.

-Adjustment of toner material liquid-
In a beaker, 80 parts by mass of styrene acrylic resin A and 100 parts of ethyl acetate were added and dissolved by stirring. As a release agent, 5 parts of paraffin wax (HNP-9, melting point 75 ° C., manufactured by Nippon Seiki Co., Ltd.), 2 parts of MEK-ST (Nissan Chemical Industry Co., Ltd.), and 10 parts of masterbatch were added. The toner material solution is prepared after three passes under the condition that 80% by volume of zirconia beads having a particle diameter of 0.5 mm are filled at a liquid feeding speed of 1 kg / hour and a peripheral speed of the disk of 6 m / second. did.

―Preparation of emulsion or dispersion―
150 parts by mass of the aqueous medium phase is placed in a container, and stirred at a rotational speed of 12,000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). The mixture was added and mixed for 10 minutes to prepare an emulsified dispersion (emulsified slurry).

―Removal of organic solvent―
100 parts by mass of the emulsified slurry was charged into a Kolben equipped with a stirrer and a thermometer, and the solvent was removed at 30 ° C. for 12 hours while stirring at a stirring peripheral speed of 20 m / min.

-Washing-
After 100 parts by mass of the dispersion slurry was filtered under reduced pressure, 100 parts by mass of ion-exchanged water was added to the filter cake, mixed with a TK homomixer (10 minutes at a rotational speed of 12,000 rpm), and then filtered. To the obtained filter cake, 300 parts by mass of ion-exchanged water was added, mixed with a TK homomixer (10 minutes at 12,000 rpm), and then filtered twice. To the obtained filter cake, 20 parts by mass of a 10% by mass aqueous sodium hydroxide solution was added, mixed with a TK homomixer (30 minutes at 12,000 rpm), and then filtered under reduced pressure. To the obtained filter cake, 300 parts by mass of ion-exchanged water was added, mixed with a TK homomixer (at 12,000 rpm for 10 minutes), and then filtered. To the obtained filter cake, 300 parts by mass of ion-exchanged water was added, mixed with a TK homomixer (10 minutes at 12,000 rpm), and then filtered twice. Furthermore, 20 mass parts of 10 mass% hydrochloric acid was added to the obtained filter cake, mixed with a TK homomixer (at a rotation speed of 12,000 rpm for 10 minutes) and then filtered.

-Surfactant adjustment-
To the filter cake obtained by the above washing, 300 parts by mass of ion-exchanged water was added, and the electrical conductivity of the toner dispersion was measured by mixing with a TK homomixer (10 minutes at 12,000 rpm). The surfactant concentration of the toner dispersion was calculated from a calibration curve for surfactant concentration prepared in advance. From this value, ion-exchanged water was added so that the surfactant concentration was the target surfactant concentration of 0.05 wt%, and a toner dispersion was obtained.

―Surface treatment process―
The toner dispersion liquid adjusted to a predetermined surfactant concentration was heated with a water bath at a heating temperature T1 = 55 ° C. for 10 hours while being mixed with a TK homomixer at 5000 rpm. Thereafter, the toner dispersion was cooled to 25 ° C. and filtered. Further, 300 parts by mass of ion-exchanged water was added to the obtained filter cake, mixed with a TK homomixer (10 minutes at 12,000 rpm), and then filtered.

―Dry―
The obtained final filter cake was dried with a circulating dryer at 45 ° C. for 48 hours, and sieved with a mesh of 75 μm to obtain toner base particles of Example 4 .

―External treatment―
Further, with respect to 100 parts by weight of the toner base particles, 0.6 part by weight of hydrophobic silica having an average particle diameter of 100 nm, 1.0 part by weight of titanium oxide having an average particle diameter of 20 nm, and hydrophobic silica having an average particle diameter of 15 nm 0.8 part of the fine powder was mixed with a Henschel mixer to obtain the toner of Example 4 .

(Example 5 )
The toner of Example 5 was prepared in the same manner except that the target surfactant concentration was adjusted to 0.09 wt% in the surfactant amount adjustment of Example 1.

(Comparative Example 1)
The toner of Comparative Example 1 was obtained in the same manner except that the surfactant adjustment and surface treatment steps of Example 1 were not performed, and the toner was obtained by washing and drying.

(Comparative Example 2)
A toner of Comparative Example 2 was prepared in the same manner as in Example 1 except that the heating temperature T1 in the surface treatment process of Example 1 was changed to 44 ° C.

(Comparative Example 3)
A toner of Comparative Example 3 was prepared in the same manner as in Example 1 except that the heating temperature T1 in the surface treatment process of Example 1 was changed to 66 ° C.

(Comparative Example 4)
The toner of Comparative Example 4 was prepared in the same manner except that the surfactant concentration in the aqueous medium was adjusted to 0.12 wt% in the adjustment of the surfactant amount in Example 1.

(Comparative Example 5)
The toner of Comparative Example 5 was prepared in the same manner as in Example 1 except that the surfactant concentration in the aqueous medium was adjusted to 0.003 wt% in the adjustment of the surfactant amount.

Table 1 shows a list of production conditions of the toners of Examples 1 to 5, Reference Examples 1 and 2 and Comparative Examples 1 to 5 obtained as described above, and Table 2 shows various physical property values of the obtained toners. Show.

<Creation of carrier>
To 100 parts of toluene, 100 parts of silicone resin organostraight silicone, 5 parts of γ- (2-aminoethyl) aminopropyltrimethoxysilane and 10 parts of carbon black are added and dispersed with a homomixer for 20 minutes. Was prepared. Using a fluidized bed type coating apparatus, the resin layer coating solution was applied to the surface of 1,000 parts of spherical magnetite having an average particle size of 50 μm to prepare a carrier.

<Production of developer>
Using a ball mill, 5 parts of toner and 95 parts of carrier were mixed to prepare a developer.

<Evaluation method and evaluation results>
The following evaluation was performed using the obtained developer. The evaluation results are shown in Table 3.
[Evaluation of toner]

[Transfer efficiency (%)]
A solid pattern of A4 size and 0.6 mg / cm2 of toner adhesion was used for each developer using an evaluation machine that was remodeled from Fuji Xerox DocuColor 8000 Digital Press and tuned so that the linear speed and transfer time could be adjusted. A running test to output as a test image was performed. After outputting 100,000 test images and 1,000,000 test images, the transfer efficiency in primary transfer was determined from the following formula (3), and the transfer efficiency in secondary transfer was determined from the following formula (4). The evaluation criteria are as follows.

評価基準は、
◎・・・９０％以上
○・・・８５％以上９０％未満
△・・・８０％以上８５％未満
×・・・８０％未満
とした。

Evaluation criteria are
◎ ... 90% or more ○ ... 85% or more and less than 90% △ ... 80% or more and less than 85% × ... less than 80%

[Transfer unevenness]
A black solid image was formed using an evaluation machine that was remodeled from Fuji Xerox DocuColor 8000 Digital Press and tuned so that the linear speed and transfer time could be adjusted, and the resulting image was visually observed for transfer unevenness. The transfer unevenness was evaluated. It should be noted that there is no transfer unevenness and a very good level (◎), there is no transfer unevenness and there is no problem in actual use (○), there is a little transfer unevenness, but actual use The determination was made with (Δ) indicating a possible level and (×) indicating that there was a transfer unevenness and a practically problematic level.

[Cover]
Using a tandem color electrophotographic apparatus imagio Neo 450 (manufactured by Ricoh Co., Ltd.) having a cleaning blade in contact with the photosensitive member and a charging roller, black solid and white solid at intervals of 1 cm in a direction perpendicular to the rotation direction of the developing sleeve. After outputting 10,000 A4 horizontal charts (image pattern A), a blank image was output and the presence or absence of fogging was visually evaluated. It should be noted that a very good level with no fogging (◎), a level with almost no fogging and no problem in actual use (○), a level with a little fogging but practically usable. A thing with a ((triangle | delta)) and a fogging and the level which has a problem practically was determined as (x).

[Cleanability]
The cleaning property was evaluated as follows. The toner remaining on the photoconductor after passing the cleaning process at the initial stage and after printing 1000 sheets and 100,000 sheets is transferred to a white paper using a scotch tape (manufactured by Sumitomo 3M) and measured with a Macbeth reflection densitometer RD514 type. The difference from the blank is less than 0.005 is good (◎), 0.005 or more and less than 0.015 (◯), 0.015 or more and less than 0.025 (△), Those exceeding 025 were judged as defective (x).

As can be seen from Table 3, Examples 1 to 5 and Reference Examples 1 and 2 are all good in primary, secondary transfer efficiency, transfer unevenness, fogging and cleaning, but in all evaluations of Comparative Examples 1 to 5. There was nothing satisfactory.

It is a schematic diagram showing an example of a developing device in the image forming method of the present invention. It is the schematic which shows an example of the roller-type charging device of this invention. It is the schematic which shows an example of the brush-type charging device in the image forming method of this invention. It is the schematic which shows an example of the process cartridge of this invention. FIG. 3 is a schematic diagram illustrating an example of a fixing device in the image forming method of the present invention. FIG. 3 is a schematic diagram illustrating an example of a layer configuration of a belt provided in a fixing device in the image forming method of the present invention. 1 is a schematic diagram illustrating an example of a configuration of an image forming apparatus of the present invention. It is the schematic which shows another example of a structure of the image forming apparatus of this invention.

Explanation of symbols

(About Figure 1)
500 Roller-type charging device 501 Charging roller 502 Core metal 503 Conductive rubber layer 504 Power source 505 Photoconductor (FIG. 2)
510 Brush-type charging device 511 Brush roller (fur brush roller or magnetic brush roller)
512 Core 513 Brush 514 Power Supply 515 Photosensitive Member (About FIG. 3)
600 Development device (developer)
601 Developing sleeve 602 Power source 603 Developing unit 604 Photoconductor 605 Toner (FIGS. 4 and 5)
700 Fixing Device 710 Heating Roller 720 Fixing Roller (Counter Rotating Body)
721 Core 722 Elastic member 730 Fixing belt (heat-resistant belt, toner heating medium)
731 Substrate 732 Heat generation layer 733 Intermediate layer 734 Release layer 740 Pressure roller (pressure rotator)
741 Core metal 742 Elastic member 750 Temperature detection member 760 Induction heating means 761 Excitation coil 762 Coil guide plate 763 Excitation coil core 764 Excitation coil core support member 770 Recording medium (recording material)
A Belt rotation direction N Fixing nip W1 Contact part T Toner image (FIG. 6)
800 Process cartridge 801 Photoconductor 802 Charging means 803 Developing means 804 Toner 805 Developing roller 806 Cleaning means (about FIG. 7)
100 Image forming apparatus 120Bk Image writing unit (black)
120C Image writing unit (cyan)
120M Image writing unit (Magenta)
120Y Image writing unit (yellow)
130Bk image forming part (black)
130C Image forming unit (cyan)
130M Image forming unit (Magenta)
130Y Image forming unit (yellow)
140 Feeder 150 Fixing Device 160 Registration Roller Pair 170 Secondary Transfer Roller 180 Transfer Belt 200Bk Developing Device (Black)
200C Developer (Cyan)
200M Developer (Magenta)
200Y Development device (yellow)
210Bk photoconductor (black)
210C photoconductor (cyan)
210M photoconductor (magenta)
210Y photoconductor (yellow)
215Bk charging device (black)
215C charging device (cyan)
215M charging device (magenta)
215Y Charging device (yellow)
220 Intermediate transfer belt 230Bk Primary transfer device (black)
230C primary transfer device (cyan)
230M Primary transfer device (Magenta)
230Y primary transfer device (yellow)
241 Conductive roller 242 Conductive roller 243 Conductive roller 250Bk Toner transfer tube (black)
250C Toner transfer tube (cyan)
250M Toner transfer pipe (Magenta)
250Y Toner transfer tube (yellow)
260 Intermediate transfer belt cleaning device 261 Conductive fur brush 262 Conductive fur brush 300Bk Cleaning device (black)
300C Cleaning device (Cyan)
300M Cleaning device (Magenta)
300Y Cleaning device (yellow)
500 Transfer belt 502 Transfer charger 600 Secondary transfer roller (reference numeral in FIG. 8)
10Y, 10C, 10M, 10K Each photoconductor 14 First support roller 15 Second support roller 16 Third support roller 17 Intermediate transfer member cleaning device 18 Image forming unit 21 Exposure unit 22 Secondary transfer unit 23 Roller 24 2 Next transfer belt 25 Fixing device 26 Fixing belt 27 Pressure roller 28 Sheet reversing device 130 Document table 32 Contact glass 33 First traveling member 34 Second traveling member 35 Imaging lens 36 Reading sensor 40 Photosensitive member 42 Feeding roller 43 Paper bank 144 Paper feed cassette 145 Separation roller 146 Paper feed path 147 Transport roller 148 Paper feed path 49 Registration roller 50 Paper feed roller 51 Manual feed tray 53 Paper feed path 55 Switching claw 56 Paper discharge roller 57 Paper discharge tray 58 Manual paper feed roller 62 1 Next transfer apparatus 100 Image forming apparatus 101 Copying apparatus main body 110 Image Forming device main body 120 Color image forming unit 130 Document placing table 142 Paper feed roller 143 Paper feed cassette 144 Paper feed cassette 145 Separating roller 146 Paper feed path 147 Transport roller 148 Paper feed path 200 Paper feed table 300 Scanner 400 Automatic document transport apparatus ( ADF)

Claims (11)

In a toner manufacturing method for obtaining toner by surface-treating colored particles, a step of preparing colored particle dispersion by dispersing colored particles in an aqueous medium containing at least a surfactant, and heating the colored particle dispersion to a Dressings containing surface treatment step, between the step and the colored particles surface treatment step of adjusting the colored particle dispersion, comprising the step of further washing the colored particles, the surface treatment step, the toner base particle surface The amount of the surfactant in the colored particle dispersion in the surface treatment step is 0.1 to 2.0 times the critical micelle concentration of the surfactant, and A method for producing a toner, wherein the heating temperature (T1) in the surface treatment step is -10 ° C or higher and lower than 10 ° C with respect to the glass transition temperature (Tg) of the toner. A step of preparing a colored particle dispersion by granulating a toner material mixture in an aqueous medium containing a surfactant, a colored particle surface treatment step of heating the colored particle dispersion, and a surface-treated colored particle from the dispersion was filtered, to obtain the toner base particles and dried, and treated with an external additive to toner base particles are Dressings containing obtaining a toner, the surface of the colored particles and the step of adjusting the colored particle dispersion A step of washing the colored particles between the treatment steps, wherein the surface treatment step is a step of reducing irregularities on the surface of the toner base particles, and the interface in the colored particle dispersion in the colored particle surface treatment step The amount of the activator is 0.1 to 2.0 times the critical micelle concentration of the surfactant, and the heating temperature (T1) is −10 ° C. or more and less than 10 ° C. with respect to the glass transition temperature (Tg) of the toner. In Method for producing a toner, characterized in that. The step of adjusting the colored particle dispersion comprises dissolving or dispersing at least a resin material, a colorant, a release agent, and a toner material in an organic solvent, and dispersing the dispersion or dispersion in an aqueous medium containing a surfactant. 3. The toner production method according to claim 1, wherein the toner production method is a step of adjusting the colored particle dispersion. The step of preparing the colored particle dispersion comprises dissolving at least an unmodified polyester resin, a modified polyester resin capable of bonding with urea or urethane, an amine, a colorant, and a toner material containing a release agent in an organic solvent. Colored particles containing a polyester resin having a urea or urethane bond obtained by dispersing, dispersing the dispersion or dispersion in an aqueous medium containing a surfactant, and reacting the modified polyester resin with the amine 4. The toner manufacturing method according to claim 1, wherein the toner is a step of adjusting a dispersion. The toner obtained by the toner manufacturing method according to claims 1 to 4. The ratio Sbet / Dv between the BET specific surface area (Sbet) of the toner and the volume average particle diameter (Dv) of the toner is 2.0 × 10 ⁵ m / g or more and less than 4.0 × 10 ⁵ m / g. The toner according to claim 5 . The toner according to claim 5, wherein the toner has an average circularity of 0.940 or more and less than 0.970. The toner according to claim 5, wherein the toner has a volume average particle diameter of 1.0 μm or more and less than 6.0 μm. A charging step for charging the electrophotographic photosensitive member by a charging unit; an exposure step for forming an electrostatic latent image on the charged electrophotographic photosensitive member by an exposing unit; and an electrophotographic photosensitive member on which the electrostatic latent image is formed. A developing process for forming a toner image on the body using toner by a developing means, a primary transfer process for transferring the toner image formed on the electrophotographic photosensitive member onto an intermediate transfer body by a primary transfer means, and the intermediate A secondary transfer step of transferring the toner image transferred onto the transfer body onto a recording material by a secondary transfer means, and a recording material by means of a fixing means including a heat and pressure fixing member for transferring the toner image transferred onto the recording material. A fixing step of fixing the toner image on the surface of the electrophotographic photosensitive member having the toner image transferred onto the intermediate transfer member by the primary transfer unit; And a ring step, full-color image forming method, wherein the toner in the developing step is a toner according to any one of claims 5 to 8. In the secondary transfer step, the linear speed of transfer of the toner image to the recording material is 300 to 1000 mm / sec, and the transfer time at the nip portion of the secondary transfer means is 0.5 to 20 msec. The full-color image forming method according to claim 9 . 11. The full color image forming method according to claim 9 , wherein a tandem type electrophotographic image forming process is employed.

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