JP5253046B2 - Image forming method - Google Patents

Description

  The present invention relates to an electrostatic image developing toner and an image forming method used for developing an electrostatic latent image in electrophotography and electrostatic recording. More specifically, the present invention relates to an image forming method used in an image recording apparatus that can be used in a copying machine, a printer, a facsimile, or the like.

  In recent years, the technological trend of printers has progressed toward the miniaturization and speeding up of machines, and it has come to be used in various usages and environments regardless of whether it is a home or office.

  On the other hand, users are demanding printing on a wide variety of transfer materials. An intermediate transfer system that forms a multicolor image on an intermediate transfer body and transfers the multicolor image to an image fixing material at one time is a transfer material. Many have been adopted in that they can be transferred without choosing any of them.

  However, in the image forming method using the intermediate transfer member, the transfer efficiency generally tends to be lower than that in the image forming method not using the intermediate transfer member. Further, when the transfer residual toner on the intermediate transfer member cannot be sufficiently collected, an image adverse effect that the transfer residual toner is printed on the image tends to occur.

  For this reason, it is necessary to install a large-scale toner collection process, waste toner BOX, and the like in the machine, and so far, reduction of parts in the toner collection process, such as waste toner BOX, has been studied from the viewpoint of miniaturization.

  In order to solve the above problem, there has been proposed an image forming method in which the transfer residual toner is reversely charged using a charging roller or a charging brush and returned to the latent image carrier to perform cleaning (for example, Patent Documents 1 to 5). reference).

  In particular, when a charging brush is used, there is an effect that the transfer residual toner is dispersed on the intermediate transfer body and there is an effect of charging, and a charging roller is used because the transfer residual toner can be uniformly charged. Compared to the case, there was a tendency to be more advantageous for cleaning the intermediate transfer member.

  On the other hand, due to the diversification of printer use environments, the temperature has become low near 0 ° C. at night, and printers have been used even in cold regions where the temperature is extremely low and low humidity in the daytime.

  In the above environment, the fluidity of the toner tends to decrease due to an increase in electrostatic cohesion, and the transfer residual toner tends to stay on the brush in the cleaning method using a charging brush.

  Further, in the environment, brush contamination tends to easily progress due to the increase in electrostatic adhesion force due to toner and external additives released from the toner.

  As a result, the transfer residual toner on the intermediate transfer member cannot be sufficiently charged from the charging brush, making it difficult to collect by the latent image carrier, and as a result, the intermediate transfer member tends to be poorly cleaned. there were.

  On the other hand, a need from the market is to continue to provide a stable image under any environment, and a toner excellent in cleaning on an intermediate transfer body is required even in such an environment.

JP-A-1-105980 JP-A-4-340564 Japanese Patent Laid-Open No. 5-29739 Japanese Patent Laid-Open No. 9-50167 JP-A-10-333454

  An object of the present invention is to provide an image forming method that solves the above-mentioned problem, that is, a cleaning failure in a cleaning process in which a charge is applied to a transfer residual toner on an intermediate transfer member and collected by a latent image carrier using a charging brush. There is.

  As a result of intensive studies, the present inventors have found that the above problem can be solved by the following configuration, and have completed the present invention.

That is, the present invention repeats the formation of the toner image on the first image carrier and the primary transfer of the toner image onto the second image carrier for the plurality of color toner images. An image forming method for forming a color image by superimposing a plurality of color toner images on a carrier and then secondarily transferring the plurality of color toner images to a transfer material at once.
The Grant charge by a charging brush against the remaining residual toner on said after the secondary transfer second image bearing member, is transferred to the first image bearing member from said second image carrier And a step of recovering the toner transferred onto the first image carrier from the second image carrier with a cleaning device for cleaning the first image carrier ,
A front Symbol charging bristle density of the brush 1.0 × 10 ⁷ to 1.0 × 10 ⁹ (present / m ^2),
Mean diameter I ([mu] m) is 10 to 70 ([mu] m) Der hair single prior Symbol charging brush is,
The toner has toner particles and fatty acid metal salt,
The fatty acid metal salt is externally added in an amount of 0.05 to 0.50 parts by mass with respect to 100.00 parts by mass of toner particles .
Before SL or less 25.0% free rate is 1.0% or more from the toner of the fatty acid metal salt,
The present invention relates to an image forming method characterized by satisfying a relationship of 0.15 ≦ D50s ≦ 1.00 when a volume-based median diameter (D50) of the fatty acid metal salt is D50s (μm).

  According to the present invention, in an image forming method having a cleaning step of applying a charge to a transfer residual toner on an intermediate transfer member using a charging brush and recovering the toner with a latent image carrier, printing is performed in a cryogenic low-humidity environment. However, it is possible to provide an image forming method excellent in the cleaning property of the transfer residual toner on the intermediate transfer member over a long period of time.

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

In the image forming method of the present invention, the formation of the toner image on the first image carrier and the primary transfer of the toner image onto the second image carrier are repeated for the plurality of color toner images. After superimposing a plurality of color toner images on the image carrier, the plurality of color toner images are collectively transferred to a transfer material to form a color image, and after the second transfer, the second image is formed. The transfer residual toner remaining on the carrier is transferred onto the first image carrier from the second image carrier by applying a charge with at least one charging brush, and further The image bearing member is collected by a cleaning device, and the charging brush has a bristle density of 1.0 × 10 ^{7 to} 1.0 × 10 ⁹ (lines / m ² ), and the charging brush Formation with an average diameter I (μm) of one brush of 10 to 70 (μm) In the method
The toner is a toner in which at least 0.05 to 0.50 parts by mass of a fatty acid metal salt is externally added to 100.00 parts by mass of toner particles, and the liberation ratio of the fatty acid metal salt to the toner is 1.0%. More than 25.0%,
When the volume-based median diameter (D50) of the fatty acid metal salt is D50s (μm), it is a great feature that the relationship of 15 ≦ D50s ≦ 1.00 is satisfied.

  An example of an image forming apparatus using an image forming method to which the present invention is applied will be described below. This is shown in FIG. 1 and the configuration of the present invention will be described in more detail. However, this does not limit the present invention in any way. Absent.

  FIG. 1 is a schematic configuration diagram of an example of an image forming apparatus according to the present invention.

  The image forming apparatus of the present example is a tandem type in which photosensitive drums that are a plurality of first image carriers 1 (latent image carriers) are arranged side by side.

  The image forming apparatus has a second image carrier 30 (intermediate transfer belt) and a charging brush (fixed charging brush in the figure) 34 for charging the transfer residual toner on the second image carrier. This is an electrophotographic color (multicolor image) printer.

  In this example, an electrophotographic color printer of four colors of yellow, magenta, cyan, and black is given as an example, but the color, the number of colors, and the color order are not limited at all.

  In each of the first to fourth image forming units PY, PM, PC, and PBk, each photosensitive drum 1 that is driven to rotate forward is charged by a charging roller 2 to which a charging bias is applied from a power circuit (not shown) during the rotation process. The primary charging is uniformly performed to a predetermined polarity and potential.

  Light image exposures LY, LM, LC, and LBk, which are color separation component images of full-color images, respectively according to the image patterns of yellow, magenta, cyan, and black, are formed on the charging surface by the LED array device 3, respectively. Through the exposure process, an electrostatic latent image of image information is formed on each photosensitive drum 1.

  The electrostatic latent image is developed on each of the photosensitive drums 1 of the first to fourth image forming portions PY, PM, PC, and PBk through a developing process in which the electrostatic latent image is developed as a toner image by the developing device 4. In each of the electrophotographic processes, color toner images of yellow, magenta, cyan, and black, which are color separation component images of a full-color image, are formed at a predetermined sequence control timing.

  In each of the first to fourth image forming units PY, PM, PC, and PBk, yellow, magenta, cyan, and black color toner images are formed on the surface of each photosensitive drum 1.

  Next, the first to fourth images are respectively applied to the surface of the intermediate transfer belt 30 that is driven to rotate at the same speed as the photosensitive drum 1 in the clockwise direction indicated by the forward arrow in the forward rotation direction of each photosensitive drum 1. In the primary transfer portions of the formation portions PY, PM, PC, and PBk, the primary transfer rollers are sequentially transferred (primary transfer) by a primary transfer bias applied from a power supply circuit (not shown) (primary transfer step).

  Through the primary transfer process, an unfixed full-color toner image (mirror image) is synthesized and formed on the surface of the intermediate transfer belt 30 that is rotationally driven.

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

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

  A contact portion between the secondary transfer roller 32 and the intermediate transfer belt 30 is a secondary transfer portion.

  Reference numeral 40 denotes a paper feed cassette disposed in the lower part of the main body of the image forming apparatus, in which a transfer material P as a final recording medium is stacked and accommodated.

  The conveying means (pickup roller) 31 is driven at a predetermined sequence control timing to separate and feed one transfer material P in the paper feed cassette 40, and is fed to the secondary transfer unit at a predetermined timing.

  An unfixed full-color toner image synthesized and formed on the intermediate transfer belt 30 is transferred onto the surface of the transfer material P by a secondary transfer bias applied from a power supply circuit (not shown) to the secondary transfer roller 32 in the secondary transfer portion. Transfer is performed through a secondary transfer process in which batch transfer is performed.

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

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

  In the present invention, the untransferred toner remaining on the intermediate transfer belt 30 in the secondary transfer step is dispersed on the intermediate transfer belt by the charging brush 34 that is in contact with the intermediate transfer belt 30 and is given a charge.

  The charging brush may be a rotating brush or a fixed brush.

The density of the bristle of the charging brush used in the present invention is 1.0 × 10 ^{7 to} 1.0 × 10 ⁹ (lines / m ² ), and the average diameter I (μm) of one brush of the charging brush. Is 10 to 70 (μm).

The volume resistance value of the brush in the present invention is preferably 1.0 × 10 ^{4 to} 1.0 × 10 ¹⁰ Ω · cm because a preferable charge can be imparted to the toner.

  The material of the charging brush is not limited in any way, but examples thereof include those in which the resistance value is controlled by adding carbon or metal powder to fibers such as rayon, acrylic, and polyester.

  Further, it is preferable to use the charging roller 33 in combination in that the toner can be further charged.

  In order to satisfactorily charge the transfer residual toner, it is possible to apply a bias to the transfer residual toner from the charging brush and the charging roller.

  The bias to be applied is preferably 500 to 2500V.

  The charged transfer residual toner is transferred to an arbitrary drum from the intermediate transfer belt 30 to an arbitrary primary transfer roller 5 by a primary transfer bias applied from a power supply circuit (not shown).

  Thereafter, the toner is removed by the cleaning blade 6a of the blade cleaning device 6 and sent to the waste toner box 6 in the image forming unit for storage.

  More preferably, the image forming unit that performs the secondary transfer residual toner cleaning step is appropriately changed.

  As a result, the waste toner is collected without being biased to the waste toner box 6 in each image forming unit, so that the apparatus can be further reduced in size (secondary transfer residual toner cleaning step).

  By having the secondary transfer residual toner cleaning step as described above, it is possible to further reduce the size of the apparatus by reducing members such as a cleaning blade and a waste toner collection box for cleaning the intermediate transfer belt.

  Compared to charging the transfer residual toner with the charging roller, the charging brush disperses the transfer residual toner to charge the toner efficiently, improving the transfer to the drum, and cleaning drum on the drum. It can be expected to reduce the recovery load due to.

  However, since a member with a special structure called a charging brush is used, there is a tendency that untransferred toner remains on the brush or the brush is contaminated when printing over a long period of time in an extremely low temperature and low humidity environment. there were.

  For this reason, when printing is performed for a long time in a low-temperature and low-humidity environment, it becomes impossible to give a sufficient and uniform charge to the transfer residual toner by the charging brush, which tends to cause cleaning failure.

  As a result of intensive studies, the present inventors have found that the above problem can be solved by using a toner in which a fine fatty acid metal salt is externally added to toner particles so as to have an appropriate release rate.

Specifically, it is a toner in which at least 0.05 to 0.50 parts by mass of a fatty acid metal salt is externally added to 100.00 parts by mass of toner particles, and the liberation ratio of the fatty acid metal salt to the toner is 1.0. % To 25.0%, when the volume-based median diameter (D50) of the fatty acid metal salt is D50s (μm),
0.15 ≦ D50s ≦ 1.00
The above problem is solved by using a toner satisfying the above relationship.

  Although the specific mechanism is not clear, it is considered that the toner of the present invention is improved in lubricity between the toner and the charging brush by the external addition of the fatty acid metal salt.

  Therefore, even in an extremely low temperature and low humidity environment, the transfer residual toner is less likely to stay in the brush, and it is easy to obtain an effect of efficiently dispersing the transfer residual toner on the intermediate transfer member and imparting an electric charge. It is predicted that high cleaning properties can be obtained.

  In addition, since fatty acid metal salts have a smaller particle size than conventional ones and are easily externally added to toner particles and are not easily released, brush contamination due to the release of fatty acid metal salts tends not to occur, resulting in high cleaning properties. I think it is possible to maintain.

  Furthermore, since it is a fine fatty acid metal salt having an appropriate release rate, it is possible to charge the transfer residual toner over a long period of time by suppressing brush contamination due to the release of the fatty acid metal salt due to friction with the brush. I guess.

  On the other hand, the improvement in lubricity of the brush itself due to the release of moderate fine fatty acid metal salt makes it difficult for the toner to stay in the brush, and it is assumed that the transfer residual toner can be charged well over a long period of time. Yes.

  In the toner of the present invention, a fatty acid metal salt is preferably added in an amount of 0.05 to 0.50 parts by mass with respect to 100.00 parts by mass of toner particles, and more preferably 0.10 to 0.30 parts by mass. It is.

  When the number of added parts is less than 0.05, the effect of adding the fatty acid metal salt tends to be small, and the toner tends to stay in the brush.

  On the other hand, when the ratio is larger than 0.50, the fatty acid metal salt is likely to be liberated, and it becomes difficult to uniformly charge the transfer residual toner due to the contamination of the charging brush by the fatty acid metal salt, which tends to cause poor cleaning.

  The liberation rate of the fatty acid metal salt with respect to the toner is preferably 1.0% or more and 25.0% or less, and more preferably 2.0% or more and 20.0% or less.

  When the liberation rate is less than 1.0%, it becomes difficult to maintain the lubricity of the brush due to moderate liberation of fine fatty acid metal salts, and the toner tends to stay in the brush, resulting in transfer on the intermediate transfer member. It tends to be difficult to impart sufficient charge to the remaining toner.

  On the other hand, if the liberation rate is larger than 25.0%, member contamination due to liberation of the fatty acid metal salt tends to proceed.

  Further, in the case of printing for a long time due to liberation of the fatty acid metal salt, the lubrication effect by the fatty acid metal salt is reduced due to the liberation of the fatty acid metal salt, and the toner tends to stay in the charging brush.

  The liberation rate of the fatty acid metal salt in the toner in the present invention was calculated as follows.

  Using a powder tester (manufactured by Hosokawa Micron Corporation) having a digital vibrometer (Digivibro MODEL 1332), the amount of fatty acid metal salt before and after the sieve is measured with a fluorescent X-ray analyzer Axios (manufactured by PANallytical), measurement condition setting and measurement data analysis The amount of fatty acid metal salt liberation was determined using the attached dedicated software “SuperQ ver. 4.0F” (manufactured by PANalytical).

  As a specific measuring method, a sieve having a mesh size of 25 μm (635 mesh) is set on a vibrating table of a powder tester. 5 g of a sample accurately weighed is added to the sieve having a mesh size of 25 μm (635 mesh), the amplitude of the digital vibrometer is adjusted to about 0.60 mm, and vibration is applied for about 2 minutes. The above operation is repeated two more times, and the sample is passed through a 25 μm (635 mesh) sieve a total of three times. Next, about 4 g of the obtained sample is placed on an aluminum ring having a diameter of 40 mm, and compressed by a press machine at 150 kN to prepare a sample. The obtained sample was measured with a fluorescent X-ray analyzer (Axios). Rh is used as the anode of the X-ray tube, the measurement atmosphere is vacuum, the measurement diameter (collimator mask diameter) is 27 mm, and the measurement time is 10 seconds. Further, when measuring a light element, it is detected by a proportional counter (PC), and when measuring a heavy element, it is detected by a scintillation counter (SC).

The liberation rate of the fatty acid metal salt was determined from the following formula by measuring the Kα ray net intensity (KCPS) of the metal element of the fatty acid metal salt before and after the sieve.
{(Kα ray net intensity of metal element of fatty acid metal salt in toner before sieve) − (Kα ray net intensity of metal element of fatty acid metal salt in toner passed through sieve)} / (Fatty acid metal salt in toner before sieve) (Kα line net intensity of metallic elements)

  The volume-based median diameter D50s (μm) of the fatty acid metal salt is preferably 0.15 ≦ D50s ≦ 1.00, more preferably 0.15 ≦ D50s ≦ 0.75, and still more preferably 0. .15 ≦ D50s ≦ 0.60.

  When D50s is smaller than 0.15, it tends to be difficult to obtain a sufficient effect of adding a fatty acid metal salt.

  On the other hand, when the value is larger than 1.00, the electrostatic adhesion force with the toner particles becomes small, so that the fatty acid metal salt tends to be liberated, and the member tends to be contaminated and the toner stays in the brush.

  The volume-based median diameter D50s and span value A of the fatty acid metal salt used in the present invention are measured in accordance with JIS Z8825-2 (2001), and are specifically as follows.

  As a measuring device, a laser diffraction / scattering particle size distribution measuring device “LA-920” (manufactured by Horiba, Ltd.) is used. The dedicated software “HORIBA LA-920 for Windows (registered trademark) WET (LA-920) Ver. 2.02” attached to LA-920 is used for setting measurement conditions and analyzing measurement data. As the measurement solvent, ion-exchanged water from which impure solids are removed in advance is used.

The measurement procedure is as follows.
(1) A batch type cell holder is attached to LA-920.
(2) A predetermined amount of ion-exchanged water is put into a batch type cell, and the batch type cell is set in a batch type cell holder.
(3) The inside of the batch cell is stirred using a dedicated stirrer chip.
(4) Press the “refractive index” button on the “display condition setting” screen and select the file “110A000I” (relative refractive index 1.10).
(5) In the “display condition setting” screen, the particle diameter reference is set as the volume reference.
(6) After performing warm-up operation for 1 hour or more, optical axis adjustment, optical axis fine adjustment, and blank measurement are performed.
(7) Put about 60 ml of ion-exchanged water in a glass 100 ml flat bottom beaker. Among them, as a dispersant, “Contaminone N” (a nonionic surfactant, an anionic surfactant, a 10% by weight aqueous solution of a neutral detergent for washing a pH 7 precision measuring instrument comprising an organic builder, Wako Pure Chemical Industries, Ltd. About 0.3 ml of a diluted solution obtained by diluting the product (manufactured) with ion exchange water about 3 times by mass is added.
(8) Two oscillators with an oscillation frequency of 50 kHz are incorporated with the phase shifted by 180 degrees, and an ultrasonic disperser “Ultrasonic Dissipation System Tetora 150” (manufactured by Nikki Bios Co., Ltd.) having an electrical output of 120 W is prepared. About 3.3 l of ion-exchanged water is placed in the water tank of the ultrasonic disperser, and about 2 ml of Contaminone N is added to the water tank.
(9) The beaker of (7) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. And the height position of a beaker is adjusted so that the resonance state of the liquid level of the aqueous solution in a beaker may become the maximum.
(10) In a state where the aqueous solution in the beaker of (9) is irradiated with ultrasonic waves, about 1 mg of a fatty acid metal salt is added to the aqueous solution in the beaker little by little and dispersed. Then, the ultrasonic dispersion process is continued for another 60 seconds. In this case, the fatty acid metal salt may solidify and float on the liquid surface. In that case, ultrasonic dispersion is performed for 60 seconds after the mass is submerged by shaking the beaker. Moreover, in ultrasonic dispersion, it adjusts suitably so that the water temperature of a water tank may become 10 to 40 degreeC.
(11) The aqueous solution in which the fatty acid metal salt prepared in the above (10) is dispersed is immediately added little by little to a batch type cell, taking care not to enter bubbles, and the transmittance of the tungsten lamp is 90% to 95%. Adjust so that Then, the particle size distribution is measured. Based on the obtained volume-based particle size distribution data, the median diameter (D50), 5% integrated diameter (D5s), and 95% integrated diameter (D95s) are obtained, and the span value A is calculated from the following equation (1). .
Span value A = (D95s−D5s) / D50s (1) Formula

  The span value A of the fatty acid metal salt is preferably 1.75 or less, more preferably 1.00 or less.

  When the span value A is larger than 1.75, the particle size of the fatty acid metal salt varies, and therefore, there is a tendency that the charge applied to the untransferred toner varies.

  In addition, the cohesion of the toner is increased as a result of the variation in the particle diameter, and the toner tends to stay in the brush. The volume-based median diameter D50t (μm) of the toner is preferably 4.0 ≦ D50t ≦ 9.0, and more preferably 4.0 ≦ D50t ≦ 7.0.

  When D50t is smaller than 4.0, the toner itself is likely to be stored in the brush, and the cleaning performance tends to be deteriorated. When it is larger than 9.0, the fine line reproducibility is deteriorated. There is a tendency not to satisfy.

  When the toner has an average circularity of 0.960 to 0.995 as measured by a flow particle image analyzer, the toner can be triboelectrically charged by lubrication by reducing the mechanical load applied to the toner. Is preferable in that it is easily charged uniformly.

  On the other hand, if it is less than 0.960, the added fatty acid metal salt is present in the concave portion of the toner surface, and the charge distribution tends to occur in the particles, so that it is difficult to uniformly charge the transfer residual toner. is there.

The toner particles of the present invention have a volume resistance value of 1.0 × 10 ^{13 to} 1.0 × 10 ¹⁷ Ω · cm at an electric field strength of 5 × 10 ³ V / cm, which is appropriate due to frictional charging with the brush. It is preferable in that it can be easily charged.

  The toner particles of the present invention are not particularly limited as long as the toner production method can achieve the characteristics, and a known production method can be used.

  Among the known production methods, the toner particles of the present invention are obtained by dispersing a polymerizable monomer composition containing at least a polymerizable monomer, a colorant, a polar resin, a release agent and a polymerization initiator in an aqueous medium. The toner particles are preferably produced by granulating and polymerizing a polymerizable monomer.

  The toner particles synthesized by the granulation method have a sharp particle size distribution and are easy to obtain a toner having a high degree of circularity, tend to increase the fluidity of the toner, cause tribocharging, and easily obtain excellent charging performance.

  Hereinafter, the most suitable suspension polymerization method for obtaining the toner particles used in the present invention will be exemplified and the production method of the toner particles will be described.

  Dissolve or disperse the polymerizable monomer, colorant, polar resin, release agent and other additives as required uniformly using a disperser such as a homogenizer, ball mill, colloid mill, or ultrasonic disperser. In this, a polymerization initiator is dissolved to prepare a polymerizable monomer composition.

  Next, the polymerizable monomer composition is dispersed in an aqueous medium containing a dispersion stabilizer and granulated to form particles, and toner particles are produced by polymerizing the polymerizable monomer in the particles. To do.

  The polymerization initiator may be added at the same time when other additives are added to the polymerizable monomer, or may be mixed immediately before the polymerizable monomer composition is dispersed in the aqueous medium. .

  Also, a polymerization initiator dissolved in a polymerizable monomer or solvent can be added immediately after granulation and before starting the polymerization reaction.

  In the present invention, it is preferable to add an appropriate acid for pH adjustment at the time of dispersion, granulation, and before starting the polymerization reaction.

  As the acid used in the toner of the present invention, commonly used acids such as hydrochloric acid, sulfuric acid, and nitric acid can be used.

  By adjusting the aqueous solution during polymerization to an appropriate pH, it is possible to obtain a toner having more uniform charging performance.

  When a polar resin is added during the polymerization reaction from the dispersion step of the polymerizable monomer composition to the polymerization step, the polarity varies depending on the balance between the polarity of the polymerizable monomer composition to be toner particles and the aqueous dispersion medium. The presence state of the resin can be controlled.

  That is, by adding a polar resin, functional separation according to the resin layer is possible. Further, the toner particles obtained by the suspension polymerization method are preferable because they have a core-shell structure including a release agent component.

  Examples of the polar resin include polyester resin, epoxy resin, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, and styrene-maleic acid copolymer.

  A polyester resin is particularly preferable, and the acid value is preferably in the range of 4 to 20 mgKOH / g. When the acid value is less than 4 mgKOH / g, it is difficult to form a shell structure, and the rise of charging is slow, which tends to cause problems such as a decrease in image density and fogging.

  When the acid value exceeds 20 mgKOH / g, the chargeability is affected and the developability tends to deteriorate. The molecular weight of 3,000 to 30,000 is preferably a main peak molecular weight because the fluidity and negative frictional charging characteristics of the toner particles can be improved.

  A preferable addition amount of the polar resin is 1 to 25 parts by mass, and more preferably 2 to 15 parts by mass with respect to 100 parts by mass of the polymerizable monomer constituting the binder resin.

  If the amount is less than 1 part by mass, the presence state of the polar resin in the toner particles tends to be non-uniform. On the other hand, if it exceeds 25 parts by mass, the layer of the polar resin formed on the surface of the toner particles becomes thick.

  As the polymerizable monomer constituting the binder resin used in the toner of the present invention, generally used styrene-acrylic copolymer, styrene-methacrylic copolymer, epoxy resin, styrene-butadiene copolymer Coalescence is mentioned.

  As the polymerizable monomer constituting the binder resin, a vinyl polymerizable monomer capable of radical polymerization can be used. As the vinyl polymerizable monomer, a monofunctional polymerizable monomer or a polyfunctional polymerizable monomer can be used.

  Examples of the polymerizable monomer for constituting the binder resin include the following. Styrene; Styrenic monomers such as o- (m-, p-) methylstyrene, m- (p-) ethylstyrene; methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, Propyl methacrylate, butyl acrylate, butyl methacrylate, octyl acrylate, octyl methacrylate, dodecyl acrylate, dodecyl methacrylate, stearyl acrylate, stearyl methacrylate, behenyl acrylate, behenyl methacrylate, 2-ethylhexyl acrylate, Acrylic acid ester monomers such as 2-ethylhexyl methacrylate, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate and diethylaminoethyl methacrylate, Ether-based monomers; butadiene, isoprene, cyclohexene, acrylonitrile, methacrylonitrile, acrylic acid amide, such as ene-based monomers methacrylamide.

  These polymerizable monomers are used alone or in general, and have a theoretical glass transition point (Tg) described in publication polymer handbook 2nd edition III-p139 to 192 (John Wiley & Sons) of 40 ° C. to A polymerizable monomer is appropriately mixed and used so as to exhibit 75 ° C.

  When the theoretical glass transition point is less than 40 ° C., a problem is likely to occur from the viewpoint of the durability stability of the toner, whereas when it exceeds 75 ° C., the glossiness at low temperature fixing is lowered.

  In the present invention, it is possible to add a low molecular weight polymer in order to make the THF soluble content of the toner have a preferable molecular weight distribution and improve the low-temperature fixing performance.

  The low molecular weight polymer can be added to the polymerizable monomer composition when toner particles are produced by suspension polymerization.

  The low molecular weight polymer has a weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) in the range of 2,000 to 5,000, and Mw / Mn is less than 4.5, preferably Those of less than 3.0 are preferred in terms of fixability and developability.

  Examples of low molecular weight polymers include: Homopolymers of styrene such as polystyrene and polyvinyltoluene and substituted products thereof; styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene- Ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-dimethylaminoethyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate Copolymer, styrene-butyl methacrylate copolymer, styrene-dimethylaminoethyl methacrylate copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer , Styrene-butadi Copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, styrene copolymer such as styrene-maleic acid ester copolymer; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, Polypropylene, polyvinyl butyral, silicone resin, polyester resin, polyamide resin, epoxy resin, polyacrylic resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin.

  In addition, the said low molecular weight resin can be used individually or in mixture.

  Among these low molecular weight resins, the glass transition point of the low molecular weight resin is preferably 40 to 100 ° C. If the glass transition point is less than 40 ° C., the toner particles tend to deteriorate. On the other hand, if the glass transition point exceeds 100 ° C., the problem of poor fixing tends to occur.

  The glass transition point of the low molecular weight resin is preferably 40 to 70 ° C., more preferably 40 to 65 ° C. from the viewpoint that low temperature fixability can be obtained.

  The addition amount of the low molecular weight resin is preferably 0.1 to 75.0 parts by mass with respect to 100.0 parts by mass of the polymerizable monomer constituting the binder resin in the toner particles. If the amount is less than 0.1 parts by mass in 100.0 parts by mass of the polymerizable monomer constituting the binder resin in the toner particles, the effect of adding the low molecular weight resin is small. On the other hand, if it exceeds 75.0 parts by mass, the durability of the toner particles tends to decrease.

  In the present invention, a crosslinking agent may be used when the binder resin is synthesized in order to increase the mechanical strength of the toner particles and to control the molecular weight of the THF soluble component of the toner.

  Examples of the bifunctional crosslinking agent include the following. Divinylbenzene, bis (4-acryloxypolyethoxyphenyl) propane, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6 -Hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 200, # 400, # 600 diacrylate, dipropylene glycol diacrylate, polypropylene Glycol diacrylate, polyester-type diacrylate (MANDA Nippon Kayaku), and dimethacrylate instead of diacrylate Thing.

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

  The addition amount of these crosslinking agents is preferably 0.05 to 10.00 parts by mass, more preferably 0.10 to 5.00 parts by mass with respect to 100.00 parts by mass of the polymerizable monomer. Part.

  The release agent used in the present invention is preferably a hydrocarbon-based release agent, and the content of the release agent component is preferably 4.0 parts by mass with respect to 100.0 parts by mass of the polymerizable monomer. Part to 25.0 parts by weight, more preferably 7.0 parts by weight to 15.0 parts by weight.

  If the release agent content is less than 4.0 parts by mass, sufficient glossiness cannot be obtained at low temperature fixing. On the other hand, if it is larger than 25.0 parts by mass, the durability is lowered.

  Furthermore, the release agent preferably has a maximum endothermic peak temperature in the range of 40 ° C. to 110 ° C., more preferably, in the DSC curve at the time of temperature rise measured by a differential scanning calorimetry (DSC) device. 45 ° C to 90 ° C.

  When the maximum endothermic peak temperature is less than 40 ° C., the durability of the toner decreases. On the other hand, when the maximum endothermic peak temperature exceeds 110 ° C., the glossiness at the time of low-temperature fixing decreases.

  The release agent used in the present invention is particularly preferably a release agent having a small polar component such as a hydrocarbon-based release agent in that it is easily encapsulated in the toner particle central part.

  Examples of other mold release agents include the following. Amide waxes, higher fatty acids, long chain alcohols, ketone waxes, ester waxes, and derivatives such as these graft compounds and block compounds. If necessary, two or more release agents may be used in combination.

  Examples of the hydrocarbon release agent include the following. Petroleum wax such as paraffin wax, microcrystalline wax, petrolatum and derivatives thereof; Fischer-Tropsch wax and derivatives thereof according to Fischer-Tropsch method; polyolefin wax such as polyethylene wax and polypropylene wax and derivatives thereof. Derivatives include oxides, block copolymers with vinyl monomers, and graft modified products. Further examples include hydrogenated castor oil and derivatives thereof, vegetable waxes and animal waxes. These waxes can be used alone or in combination of two or more.

  Note that an antioxidant may be added to these hydrocarbon release agents as long as the chargeability of the toner is not affected.

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

  The amount of these polymerization initiators used varies depending on the desired degree of polymerization, but is generally 3 to 20 parts by mass with respect to 100 parts by mass of the polymerizable vinyl monomer.

  The kind of the polymerization initiator varies slightly depending on the polymerization method, but is used alone or in combination with reference to the 10-hour half-life temperature.

  The toner of the present invention contains a colorant as an essential component in order to impart coloring power. Examples of the colorant preferably used in the present invention include the following organic pigments, organic dyes, and inorganic pigments.

  Examples of organic pigments or organic dyes as cyan colorants include copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, and basic dye lake compounds.

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

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

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

  Examples of the organic pigment or organic dye as the yellow colorant include compounds typified by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds.

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

  Examples of the black colorant include carbon black and those prepared by using the yellow colorant / magenta colorant / cyan colorant toned to black.

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

  The colorant is preferably used by adding 1 part by mass to 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

  In the present invention, when toner particles are obtained using a polymerization method, it is necessary to pay attention to the polymerization inhibitory property and water phase migration property of the colorant, and preferably, a hydrophobic treatment with a substance that does not inhibit polymerization is performed. It is better to apply it to the colorant.

  In particular, since dye-based colorants and carbon black have many polymerization inhibiting properties, care must be taken when using them.

  In addition, as a method for suppressing the polymerization inhibitory property of the dye-based colorant, a method of polymerizing a polymerizable monomer in the presence of these dyes in advance can be mentioned, and the obtained colored polymer is composed of a polymerizable monomer composition. Add to product.

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

  As the dispersion stabilizer used when preparing the aqueous medium, known inorganic and organic dispersion stabilizers can be used.

  Specifically, the following are mentioned as an example of an inorganic dispersion stabilizer. Tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, magnesium carbonate, calcium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina .

  Examples of the organic dispersant include the following. Polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, carboxymethyl cellulose sodium salt, starch.

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

  As the dispersion stabilizer used in preparing the aqueous medium used in the toner of the present invention, an inorganic poorly water-soluble dispersion stabilizer is preferable, and it is preferable to use a poorly water-soluble inorganic dispersion stabilizer that is soluble in acid. .

  In the present invention, when an aqueous medium is prepared, the amount of these dispersion stabilizers used is 0.2 to 2.0 parts by mass with respect to 100.0 parts by mass of the polymerizable monomer. Preferably there is. In the present invention, it is preferable to prepare an aqueous medium using 300 parts by mass to 3,000 parts by mass of water with respect to 100 parts by mass of the polymerizable monomer composition.

  In the present invention, when preparing an aqueous medium in which the above dispersion stabilizer is dispersed, a commercially available dispersion stabilizer may be used as it is.

  In order to obtain particles of a dispersion stabilizer having a fine uniform particle size, an aqueous medium may be prepared by generating a dispersion stabilizer in a liquid medium such as water under high-speed stirring.

  For example, when tricalcium phosphate is used as a dispersion stabilizer, a preferred dispersion stabilizer can be obtained by mixing sodium phosphate aqueous solution and calcium chloride aqueous solution under high speed stirring to form fine particles of tricalcium phosphate. Can do.

  In the toner of the present invention, a charge control agent can be mixed with toner particles and used as necessary. By adding a charge control agent, it is possible to improve and stabilize the charge characteristics, and to control the optimum triboelectric charge amount according to the development system.

  As the charge control agent, a known one can be used, and a charge control agent that has a high charging speed and can stably maintain a constant charge amount is particularly preferable.

  Further, when the toner particles are produced by a direct polymerization method, a charge control agent having a low polymerization inhibition property and a small amount of solubilized products in an aqueous medium is particularly preferable.

  Examples of the charge control agent that control the toner to be negatively charged include the following. Organic metal compounds and chelate compounds are effective, and monoazo metal compounds, acetylacetone metal compounds, aromatic oxycarboxylic acids, aromatic dicarboxylic acids, oxycarboxylic acids, and dicarboxylic acid-based metal compounds. Other examples include aromatic oxycarboxylic acids, aromatic mono- and polycarboxylic acids and metal salts thereof, anhydrides, esters, and phenol derivatives such as bisphenol. Further examples include urea derivatives, metal-containing salicylic acid compounds, metal-containing naphthoic acid compounds, boron compounds, quaternary ammonium salts, calixarene, and resin charge control agents.

  Among these, the polymer having a sulfonic acid functional group as a charge control agent is preferably a polymer or copolymer having a sulfonic acid group, a sulfonic acid group, or a sulfonic acid ester group.

Specifically, a polymer having a sulfonic acid group having the following structure is exemplified.
X (SO ₃ ⁻ ) n · mY ^{k +}
(X represents a polymer site derived from the polymerizable monomer, Y ^{k +} represents a counter ion, k is a valence of the counter ion, m and n are integers, and n = k × m is there.)

  In this case, the counter ions are preferably hydrogen ions, sodium ions, potassium ions, calcium ions, and ammonium ions.

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

  A preferable blending amount of the charge control agent is 0.01 to 20.00 parts by mass, more preferably 0.50 to 10.00 parts by mass with respect to 100.00 parts by mass of the polymerizable monomer. .

  The toner of the present invention is a toner in which a fatty acid metal salt is externally added to toner particles. The fatty acid metal salt suitably used in the present invention is preferably a metal salt selected from zinc, calcium, magnesium, aluminum and lithium, more preferably zinc or calcium salt.

Further, the volume resistance value of the fatty acid metal salt of the present invention at an electric field strength of 5 × 10 ³ V / cm is 1.0 × 10 ^{13 to} 1.0 × 10 ¹⁷ Ω · cm due to frictional charging with the brush. It is preferable in that it is easily charged properly.

  In the present invention, when a fatty acid having 12 or more carbon atoms is used, free fatty acid can be easily suppressed and preferably used. The free fatty acid is preferably 0.20% or less, and if it is more than 0.20%, fog is likely to occur.

  In the toner of the present invention, inorganic fine powder can be externally added as necessary. In that case, it is preferable from the viewpoint of charging stability that the fatty acid metal salt is exposed on the outermost surface of the toner.

  Examples of the inorganic fine powder include fine powder such as silica fine powder, titanium oxide fine powder, alumina fine powder, and double oxide fine powder thereof. Among the inorganic fine powders, silica fine powder and titanium oxide fine powder are preferable.

Examples of the silica fine powder include dry silica or fumed silica produced by vapor phase oxidation of silicon halide, and wet silica produced from water glass. As the inorganic fine powder, dry silica having less silanol groups on the surface and inside the silica fine powder and less Na ₂ O and SO ₃ ²⁻ is preferable. The dry silica may be a composite fine powder of silica and another metal oxide by using a metal halogen compound such as aluminum chloride or titanium chloride together with a silicon halogen compound in the production process.

  The inorganic fine powder is externally added to the toner particles in order to improve the fluidity of the toner and to make the charge of the toner particles uniform. By hydrophobizing the inorganic fine powder, it is possible to adjust the charge amount of the toner, improve the environmental stability, and improve the characteristics in a high-humidity environment. It is preferable to use it. When the inorganic fine powder added to the toner absorbs moisture, the charge amount as the toner decreases, and the developability and transferability tend to decrease, and the durability in a harsh environment tends to decrease.

  Non-modified silicone varnishes, various modified silicone varnishes, unmodified silicone oils, various modified silicone oils, silane compounds, silane coupling agents, other organosilicon compounds, and organotitanium compounds are used as hydrophobic treatment agents for inorganic fine powders. Can be mentioned. These treatment agents may be used alone or in combination.

  Among these, inorganic fine powder treated with silicone oil is preferable. More preferably, when the inorganic fine powder is hydrophobized with a coupling agent, or after the hydrophobization treatment, the hydrophobized inorganic fine powder treated with silicone oil maintains a high charge amount of toner particles even in a high humidity environment, and is stable. The point which can provide the done image is good.

  The total amount of the inorganic fine powder is preferably 1.0 to 5.0 parts by mass with respect to 100.0 parts by mass of the toner particles.

  The apparatus used in the external addition process of the present invention is not particularly limited as long as the characteristics can be achieved, and a known manufacturing method can be used. However, as an example of the apparatus, existing apparatuses such as a Henschel mixer and a super mixer can be used. A high-speed stirring type mixer can be mentioned.

  Any means may be used to control the liberation rate of the fatty acid metal salt as long as it falls within the scope of the present invention, but the fatty acid metal salt is more easily liberated than silica, which is a general external additive. It is desirable to optimize the mixing process conditions as follows.

  In the mixing step of the toner particles and the additive, the stirring blade disposed in the mixing unit moves, and the toner particles and the external additive receive energy from the stirring blade and collide with each other. Additives adhere to the surface.

  When the mixing of the toner particles and the additive starts, a difference in the movement speed between the toner particles and the additive occurs due to the difference in the particle size and specific gravity, and the chance of the toner particles and the additive colliding increases. Thereby, the homogenization of the additive in the toner proceeds mainly. When mixing is continued and the movement of the toner particles and the additive reaches a steady state, the difference in relative motion speed between the particles becomes small, and the chance of collision between the toner particles and the additive decreases. By the contact, the adhesion of the additive to the toner particles mainly proceeds.

  In the present invention, it is preferable to control the liberation rate within a certain range while maintaining the particle size of the fatty acid metal salt.

  For this purpose, it is important that the fatty acid metal salt is present more uniformly on the surface of the toner particles and efficiently adhered to the toner particles.

  In order to make the fatty acid metal salt exist more uniformly on the surface of the toner particles, a pause process is provided and the mixing process is divided into several times, resulting in several times the difference in the kinetic speed at which the additive becomes uniform. Let

  In this way, the time during which the difference in the kinetic speed between the toner particles and the fatty acid metal salt occurs is longer than when the normal mixing process is performed, thereby further homogenizing the fatty acid metal salt on the toner particle surface. It will be in an advanced state.

  Further, when the homogenization of the fatty acid metal salt on the surface of the toner particles progresses by repeating the pause process and the mixing process in this way, even when the movement of the toner particles and the fatty acid metal salt becomes steady and the adhesion proceeds, the necessary minimum Therefore, the release rate can be controlled within a desired range while suppressing the loss of fatty acid metal salt due to excessive stress.

  In addition, by providing a pause step, the toner particles, external additives, and the toner to be produced can be prevented from rising due to friction with the vessel wall, stirring blades, etc., so that exudation of wax and cracking of particles are reduced. A high-quality image can be obtained.

  The peripheral speed at the leading edge of the stirring blade in the mixing step is preferably in the range of 32.0 m / sec to 78.0 m / sec. Within this range, the energy from the stirring blade can be reduced to a level that does not accompany rapid heat generation.

  When the peripheral speed at the leading edge of the stirring blade is less than 32.0 m / sec, the strength for proceeding the adhesion strengthening treatment is insufficient and the additives are likely to be liberated. On the other hand, when the peripheral speed at the leading edge of the stirring blade exceeds 78.0 m / sec, the toner particles are likely to exude from the toner particles or crack the toner particles due to the rapid heat generation described above. Furthermore, there is a risk of losing the fatty acid metal salt particles.

  In the resting process, the stirring blade is decelerated to a peripheral speed range of 0 or more and 15.0 m / sec or less for the purpose of giving a difference in motion speed between the toner particles and the additive as described above, and the circumference thereof is 10 seconds or more. Maintaining in the speed range is preferable because a difference in the speed of movement between the toner particles and the additive occurs frequently.

  As described above, the temperature in the tank during the mixing step is preferably 42 ° C. or lower in order to suppress deterioration of the fatty acid metal salt, the toner particles, and the toner.

<Measurement of brush hair density and brush average diameter I>
The measurement of the brush bristle density and the brush bristle average diameter was performed by taking a photograph of the brush bristle magnified 500 to 1000 times with an electron microscope FE-SEM (S-4700, manufactured by Hitachi, Ltd.) and using the magnified photograph.

100 or more brushes were counted from the enlarged photograph, and the brush hair density per 1 m ² was calculated.

  The average brush diameter I was determined by arbitrarily measuring the diameter of twelve brush hairs on the enlarged photograph and taking the average value of the ten hairs excluding the maximum and minimum values as the average bristle diameter I.

<Measurement of volume resistance of member>
In the present invention, for example, measurement can be performed in a volume resistance measuring device (4140B pA MATER manufactured by Hewlett-Packard Company) in an environment of 23 ° C. and 65%.

<Measurement of volume-based median diameter D50t of toner particles>
As a measuring device, a precise particle size distribution measuring device “Coulter Counter Multisizer 3” (registered trademark, manufactured by Beckman Coulter, Inc.) using a pore electrical resistance method equipped with a 100 μm aperture tube is used.

  For setting the measurement conditions and analyzing the measurement data, the attached dedicated software “Beckman Coulter Multisizer 3 Version 3.51” (manufactured by Beckman Coulter, Inc.) is used. The measurement is performed with 25,000 effective measurement channels.

  As the electrolytic aqueous solution used for the measurement, special grade sodium chloride is dissolved in ion-exchanged water so as to have a concentration of about 1% by mass, for example, “ISOTON II” (manufactured by Beckman Coulter, Inc.) can be used.

  Prior to measurement and analysis, dedicated software was set up as follows.

  On the “Change Standard Measurement Method (SOM)” screen of the dedicated software, set the total count in the control mode to 50000 particles, set the number of measurements once, and set the Kd value to “standard particles 10.0 μm” (Beckman Coulter, Inc.) Set the value obtained using

  By pressing the “Threshold / Noise Level Measurement Button”, the threshold and noise level are automatically set. In addition, the current is set to 1600 μA, the gain is set to 2, the electrolyte is set to ISOTON II, and the “aperture tube flush after measurement” is checked.

  In the “Pulse to particle size conversion setting” screen of the dedicated software, the bin interval is set to logarithmic particle size, the particle size bin is set to 256 particle size bin, and the particle size range is set to 2 μm to 60 μm.

The specific measurement method is as follows.
(1) About 200 ml of the electrolytic solution is placed in a glass 250 ml round bottom beaker exclusively for Multisizer 3, set on a sample stand, and the stirrer rod is stirred counterclockwise at 24 rpm. Then, the dirt and bubbles in the aperture tube are removed by the “aperture flush” function of the dedicated software.
(2) About 30 ml of the electrolytic aqueous solution is put into a glass 100 ml flat bottom beaker. In this, "Contaminone N" (nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for pH7 precision measuring instrument cleaning, made by organic builder, manufactured by Wako Pure Chemical Industries, Ltd. About 0.3 ml of a diluted solution obtained by diluting 3) with ion-exchanged water is added.
(3) Two oscillators with an oscillation frequency of 50 kHz are incorporated with the phase shifted by 180 degrees, and an ultrasonic disperser “Ultrasonic Dissipation System Tetora 150” (manufactured by Nikki Bios Co., Ltd.) having an electrical output of 120 W is prepared. A predetermined amount of ion-exchanged water is placed in a water tank of an ultrasonic disperser, and about 2 ml of the contamination N is added to the water tank.
(4) The beaker of (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. And the height position of a beaker is adjusted so that the resonance state of the liquid level of the electrolyte solution in a beaker may become the maximum.
(5) In a state where the electrolytic aqueous solution in the beaker of (4) is irradiated with ultrasonic waves, about 10 mg of toner is added to the electrolytic aqueous solution little by little and dispersed. Then, the ultrasonic dispersion process is continued for another 60 seconds. In the ultrasonic dispersion, the temperature of the water tank is appropriately adjusted so as to be 10 ° C. or higher and 40 ° C. or lower.
(6) To the round bottom beaker of (1) installed in the sample stand, the electrolyte solution of (5) in which the toner is dispersed is dropped using a pipette, and the measurement concentration is adjusted to about 5%. . Measurement is performed until the number of measured particles reaches 50,000.
(7) The measurement data is analyzed with the dedicated software attached to the apparatus, and the number-based median diameter D50t is calculated. The “average diameter” on the “analysis / number statistical value (arithmetic average)” screen when the graph / number% is set in the dedicated software is the median diameter D50t based on the number of toners.

<Measurement of average circularity of toner>
The average circularity of the toner is measured using a flow type particle image measuring device “FPIA-2100” (manufactured by Sysmex Corporation). Details are as follows.

First, the circularity is calculated from the following equation.
Circularity = (perimeter of a circle having the same area as the particle projection area) / (perimeter of the particle projection image)

  Here, the “particle projected area” is the area of the binarized particle image, and the “peripheral length of the particle projected image” is the length of the contour line obtained by connecting the edge points of the particle image. . The measurement uses the perimeter of the particle image when image processing is performed at an image processing resolution of 512 × 512 (pixels of 0.3 μm × 0.3 μm).

  In the present invention, the degree of circularity is an index indicating the degree of unevenness of particles, and is 1.00 when the particles are perfectly spherical. The more complicated the surface shape, the smaller the degree of circularity.

  The average circularity C, which means the average value of the circularity frequency distribution, is calculated from the following formula (2), where ci is the circularity at the dividing point i of the particle size distribution and m is the number of measured particles.

  The circularity standard deviation SD is calculated from the following equation (3) where the average circularity C, the circularity ci of each particle, and the number of measured particles are m.

  A specific measurement method is as follows.

  First, about 10 ml of ion-exchanged water from which impure solids and the like are previously removed is put in a glass container.

  In this, "Contaminone N" (nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for pH7 precision measuring instrument cleaning, made by organic builder, manufactured by Wako Pure Chemical Industries, Ltd. About 0.1 ml of a diluted solution obtained by diluting the solution with ion exchange water about 3 times by mass.

  Further, about 0.02 g of a measurement sample is added, and dispersion treatment is performed for 2 minutes using an ultrasonic disperser to obtain a dispersion for measurement.

  As an ultrasonic disperser, two oscillators with an oscillation frequency of 50 kHz are incorporated with the phase shifted by 180 degrees, and an ultrasonic disperser with an electric output of 120 W “Ultrasonic Dispense System Tetora 150 type” (manufactured by Nikkei Bios) Is used.

  A predetermined amount of ion-exchanged water is placed in the water tank of the ultrasonic disperser, and about 2 ml of the contamination N is added to the water tank. In that case, it cools suitably so that the temperature of this dispersion may not be 40 degreeC or more.

  Further, in order to suppress variation in circularity, the installation environment of the apparatus is controlled to 23 ° C. ± 0.5 ° C. so that the in-machine temperature of the flow type particle image analyzer FPIA-2100 is 26 to 27 ° C.

  In addition, automatic focus adjustment is performed using standard latex particles of 2 μm at regular intervals, preferably every 2 hours (for example, “RESEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5200A” manufactured by Duke Scientific) is diluted with ion-exchanged water. Do.

  The flow type particle image measuring apparatus was used for measuring the circularity of the toner particles, and the particle sheath “PSE-900A” (manufactured by Sysmex Corporation) was used as the sheath liquid.

  The dispersion prepared according to the above procedure is introduced into the flow type particle image analyzer, and the concentration of the dispersion is readjusted and measured so that the toner particle concentration at the time of measurement is about 5000 particles / μl. After the measurement, the average circularity of the toner in the range of the circle equivalent diameter of 2.00 μm or more and less than 40.02 μm is obtained using this data.

The equivalent circle diameter is a value calculated as follows.
Equivalent circle diameter = (particle projected area / π) ^1/2 × 2

  “FPIA-2100”, which is a measuring apparatus used in the present invention, has a thinner sheath flow (7 μm → 4 μm) than “FPIA-1000” which has been used for observing the shape of a conventional toner. ) And the magnification of the processed particle image.

  In addition, the processing resolution of the captured image is improved (256 × 256 → 512 × 512), and the accuracy of toner shape measurement is improved.

<Toner and fatty acid metal salt volume resistance measurement method>
The volume resistance value of the toner was measured by the following method.

  An apparatus used for measuring the volume resistance value is shown in FIG. Specifically, after 0.3 to 1.0 g of the measurement sample 17 is tapped into the cylinder A having the lower electrode 11 having a diameter of 5 mm, the upper electrode 12 having a diameter of 15 mm is placed and a load of 350 g is applied. After measuring the thickness of the sample at this time, a voltage is applied from the power source 16 in increments of 0 to 100 V between the electrodes, the voltage at that time is monitored by the voltmeter 15, and the flowing current is measured by the ammeter 14. The resistance value was calculated by

The electric field was calculated from the sample thickness and the applied voltage, and the volume resistance value of the sample at 5 × 10 ³ V / cm was obtained. The measurement conditions were 23 ° C., 65% environment, and sample thickness of 0.5 to 1.0 mm.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to the examples.

[Production Example of Toner Particle (1)]
In a four-necked vessel, 60.0 parts by mass of ion-exchanged water, 300.0 parts by mass of a 0.1 mol / liter sodium phosphate aqueous solution and 10.0 parts by mass of 1.0 mol / liter-hydrochloric acid were added. The mixture was stirred at 12,000 rpm using a stirrer TK-homomixer and kept at 60 ° C.

To this, 25.0 parts by mass of 1.0 mol / liter-CaCl ₂ aqueous solution was added at once to prepare an aqueous dispersion medium containing a fine hardly water-soluble dispersion stabilizer Ca ₃ (PO ₄ ) ₂ .

-Styrene monomer 78.0 mass parts-N-butyl acrylate 22.0 mass parts-C.I. I. Pigment Blue 15: 3 8.0 parts by mass / styrene resin (polystyrene Mw = 2880, Mw / Mn = 2.2) 20.0 parts by mass / polyester resin (isophthalic acid-propylene oxide modified bisphenol A (2 mol adduct) ) -Propylene oxide modified bisphenol A (3 mol adduct) (molar ratio 30:55:15)) 8.0 parts by mass / negative charge control agent (Orient Chemical Industries, Ltd .: Bontron E88)) 0.7 parts by mass・ Wax (paraffin wax (manufactured by Nippon Seiwa): HNP-10) 12.5 parts by mass

  The material is dispersed at 5,000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), and then heated to 65 ° C. to uniformly dissolve and disperse the polymerizable monomer composition. Was prepared. After adding 7.5 parts by mass of 1,1,3,3-tetramethylbutylperoxy 2-ethylhexanoate (75% toluene solution) as a polymerization initiator to the polymerizable monomer composition, It put into the aqueous dispersion medium. And it granulated for 5 minutes, maintaining the rotation speed of a stirrer at 12,000 rpm. Thereafter, the high-speed stirrer was changed to a propeller stirrer, the internal temperature was raised to 67 ° C., and the reaction was allowed to proceed for 5 hours with slow stirring.

Next, the temperature in the container was raised to 80 ° C. and maintained for 40 minutes, and the vessel was gradually cooled to 30 ° C. at a cooling rate of 1 ° C. per minute to obtain slurry 1. Dilute hydrochloric acid was added to the container containing the slurry 1 to remove the dispersion stabilizer. Further, after filtering, washing and drying, classification was performed using a multi-division classifier utilizing the Coanda effect to obtain toner particles (1) having a number-based median diameter D50t of 5.9 μm. The obtained toner particles (1) had an average circularity of 0.990 and a volume resistance value of 5.0 × 10 ¹⁵ Ω · cm.

[Production Example of Toner Particles (2)]
・ Binder resin 100 parts by mass [Polyester resin (1)]
・ C. I. Pigment Blue 15: 3 5 parts by mass, negative charge control agent (Orient Chemical Industries, Ltd .: Bontron E88)) 0.6 parts by mass, wax (manufactured by Nippon Seiwa Co., Ltd .: HNP-10)) 5 parts by mass, divinylbenzene 3 parts by mass

  The monomer composition ratio used for the polyester resin (1) as the binder resin is shown below.

59 mol% of diol component represented by (x + y = 3.0) in the above structure
Fumaric acid 21 mol%
Terephthalic acid 11mol%
Trimellitic acid 9mol%

  The above materials were sufficiently premixed with a Henschel mixer and melt kneaded at an arbitrary barrel temperature with a twin screw extruder kneader.

  After cooling, it was coarsely pulverized using a hammer mill, and as a first stage, it was finely pulverized to a particle size of 10 μm or less with a mechanical pulverizer.

  Furthermore, as a second stage, the finely pulverized product was further pulverized by a mechanical pulverizer whose pulverization conditions were changed, and the obtained finely pulverized product was processed at 65 ° C. by a thermal spheronizer.

Thereafter, the obtained finely pulverized product is classified and spheroidized by an apparatus that simultaneously performs classification and surface modification treatment using mechanical impact force to obtain toner particles (2) having a number-based median diameter D50t of 4.5 μm. It was. Toner particles (2) had an average circularity of 0.975 and a volume resistivity of 1.1 × 10 ¹⁴ Ω · cm.

[Production Example of Fatty Acid Metal Salt (1)]
A receiving container with a stirrer was prepared, and the stirrer was rotated at 400 rpm. 500 mass parts of 0.5 mass% sodium stearate aqueous solution was thrown into this receiving container, and liquid temperature was adjusted to 83 degreeC. Next, 500 mass parts of 0.2 mass% zinc sulfate aqueous solution was dripped at this receptacle over 20 minutes. After the completion of charging the whole amount, the reaction was terminated by aging for 10 minutes at the temperature during the reaction.

  Next, the fatty acid metal salt slurry thus obtained was washed by filtration. The obtained washed fatty acid metal salt cake was roughly crushed and then dried at 105 ° C. using a continuous instantaneous air dryer.

Then, after pulverizing with a nano grinding mill [NJ-300] (manufactured by Sanrex) under conditions of an air volume of 6.0 m ³ / min and a processing speed of 80 kg / h, reslurry and fine particles using a wet centrifugal classifier After removing the coarse particles, the mixture was dried at 80 ° C. using a continuous instantaneous air flow dryer to obtain a fatty acid metal salt (1).

The fatty acid metal salt (1) obtained had a volume-based median diameter (D50) of 0.52 μm, a span value A of 1.21, and a volume resistance value of 2.0 × 10 ¹⁵ Ω · cm. Table 1 shows the physical properties of the fatty acid metal salt (1).

[Production Examples of Fatty Acid Metal Salts (2), (3), (5), (6))
Fatty acid metal salts (2), (3), (5), and (6) were obtained by appropriately changing the pulverization and classification conditions in the production example of the fatty acid metal salt (1). Table 1 shows the physical property values of the obtained fatty acid metal salts (2), (3), (5), and (6).

[Production Example of Fatty Acid Metal Salt (4)]
In the metal soap fine particle 1, the 0.5 mass% sodium stearate aqueous solution was changed to 1.0 mass% sodium stearate, the 0.2 mass% zinc sulfate aqueous solution was changed to 0.7 calcium chloride aqueous solution, and the liquid temperature was changed. A fatty acid metal salt (4) was obtained in the same manner as in the production example of the fatty acid metal salt (1) except that the temperature was 81 ° C.

  The physical property values of the fatty acid metal salt (4) obtained are shown in Table 1.

[Fatty acid metal salt (7)]
Commercially available zinc stearate (Nissan Electol MZ-2 manufactured by NOF Corporation) is used as the fatty acid metal salt (7). The physical properties of the fatty acid metal salt (7) are shown in Table 1.

[Fatty acid metal salt (8)]
Commercially available zinc stearate (SZ2000 manufactured by Sakai Chemical Industry) is used as the fatty acid metal salt (8). The physical properties of the fatty acid metal salt (8) are shown in Table 1.

[Production Example of Toner (1)]
With respect to 100.00 parts by mass of the toner particles (1), 0.10 parts by mass of the fatty acid metal salt (1) and 1.7 parts by mass of hydrophobic silica fine powder surface-treated with hexamethyldisilazane (number average primary A particle diameter: 7 nm) is mixed for 100 seconds using a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) at a rotation speed of 4000 rpm (mixing process 1).

  Immediately after the 30-second pause process (pause process 1), the mixing process is resumed, and the 100-second mixing process is performed (mixing process 2). Thereafter, a pause process of 30 seconds is taken (pause process 2). Mixing was resumed immediately after 30 seconds and mixing was continued for 100 seconds (mixing step 3).

  Thus, the toner (1) of the present invention was obtained. Table 2 shows the physical properties of the obtained toner.

[Production Example of Toner (2)]
Toner (2) is obtained by using toner particles (2) instead of toner particles (1) in the production example of toner (1) and changing the number of added fatty acid metal salt (1) to 0.05 parts. It was. Table 2 shows the physical properties of the obtained toner.

[Production Example of Toners (3) and (13)]
Toners (3) and (13) were obtained in the same manner as in the production example of toner (1) except that in the production example of toner (2), the number of added fatty acid metal salts was changed to that shown in Table 1. Table 2 shows the physical properties of the obtained toner.

[Production Example of Toner (4)]
In the production example of the toner (1), a 30-second pause process is further performed (pause process 3). Mixing was resumed immediately after 30 seconds, and mixing was continued for 100 seconds (mixing step 4). Thus, toner (4) was obtained. Table 2 shows the physical properties of the obtained toner.

[Production Example of Toner (5)]
In the toner (1) production example, a toner (5) was obtained in the same manner as in the toner (1) production example, except that the mixing step was performed twice and the pause step was performed once. Table 2 shows the physical properties of the obtained toner.

[Production Example of Toners (6) and (17)]
In the production example of the toner (1), toners (6) and (17) were obtained by changing the number of revolutions to those shown in Table 2. Table 2 shows the physical properties of the obtained toner.

[Production Example of Toner (7)]
In the production example of the toner (5), a pause process of 30 seconds is further taken (pause process 3). Mixing was resumed immediately after 30 seconds, and mixing was continued for 100 seconds (mixing step 4). Thus, toner (7) was obtained. Table 2 shows the physical properties of the obtained toner.

[Production Examples of Toners (8) to (11) and (14) to (16))
In the production example of toner (1), toners (8) to (11) and (14) to (16) are obtained by using the fatty acid metal salts shown in Table 2 instead of the fatty acid metal salt (1). It was.

[Production Example of Toner (12)]
In the production example of the toner (1), a toner (12) was obtained in the same manner as in the production example of the toner (1) except that the fatty acid metal salt was not added.

[Production Example of Toner (18)]
In the production example of the toner (6), a pause process of 30 seconds is further taken (pause process 2). Mixing was resumed immediately after 30 seconds and mixing was continued for 100 seconds (mixing step 3). Thus, toner (18) was obtained. Table 2 shows the physical properties of the obtained toner.

<Example 1>
When the toner (1) was used and the image evaluation described below was performed using the following image forming apparatus, it was excellent in the cleaning property of the transfer residual toner on the intermediate transfer body even in printing in a cryogenic environment. It was.

  Hereinafter, specific evaluation means will be described.

  As an image forming apparatus, a modified machine (process speed: 150 mm / sec) obtained by modifying a commercially available laser printer LBP-3700 (manufactured by HP) as shown in FIG. 1 was used.

  In the evaluation, 150 g of the toner (1) was filled in the cartridge and mounted in the cyan station, and dummy cartridges were mounted in the other stations.

  For the intermediate transfer member, a cleaning blade and a waste toner box were removed, and a charging brush and a charging roller capable of applying a bias were mounted instead.

  In FIG. 1, the charging brush and the charging roller are in contact with the intermediate transfer belt where the cleaning blade is normally disposed. In this embodiment, the charging brush uses a brush member made of conductive fibers.

The charging brush has a resistance value controlled by adding carbon to the fiber of rayon. In this embodiment, a brush having a brush diameter of 23 μm, 1.1 × 10 ⁸ pieces / m ² , a bristle length of 5 mm, and a brush volume resistance value of 1.3 × 10 ⁷ Ω · cm was used.

  This charging brush was brought into contact with the intermediate transfer belt so that the penetration amount was 1 mm, and the width of the contact nip was 5 mm.

  The configuration of the charging roller is a three-layer configuration in which a lower layer, an intermediate layer, and a surface layer are laminated around a core metal (supporting member). The lower layer is a foamed sponge layer, the intermediate layer is a resistance layer to obtain uniform resistance for the entire charging roller, and the surface layer is provided to prevent leakage even if there are defects such as pinholes. It is a protective layer.

  The charging roller of the present embodiment uses a stainless steel round bar with a diameter of 6 mm as a core metal, and the outer diameter as a roller is 14 mm.

  Image evaluation to be described later was performed using the image forming apparatus.

The evaluation image was adjusted to a toner applied amount of 0.40 mg / cm ² , and an image having a width of 20 cm in the longitudinal direction was used so that the printing ratio would be 1% at 5 cm from the tip. Further, LETTER size XEROX 4024 paper (manufactured by XEROX, 75 g / m ² ) was used as evaluation paper.

  Evaluation environment is normal temperature and normal humidity environment (N / N: temperature 23.5 ° C, humidity 60% RH), 0 ° C environment (temperature 0.0 ° C, humidity 50% RH) and cryogenic low humidity environment. Evaluation was performed in an environment (hereinafter referred to as a cold region mode) in which (temperature 10.0 ° C., humidity 15% RH) was alternately repeated.

  This cold region mode simulates a use environment where the storage temperature of the printer at night is as low as about 0 ° C. The mode will be described in detail below.

  First, as a pre-treatment, a storage mode is set for 10 hours in a 0 ° C. environment (temperature 0.0 ° C., humidity 50% RH), and the evaluation environment is set to a low temperature and low humidity environment (temperature 10.0 ° C., humidity 15 % RH).

  2000 images are run in a cryogenic and low humidity environment (temperature 10.0 ° C., humidity 15% RH).

  Further, after 12 hours have passed in the cryogenic low humidity environment, the environment is changed from the cryogenic low humidity environment to the 0 ° C. environment over one hour.

  After standing at 0 ° C. for 10 hours, the cycle is repeated 4 times.

  In both environments, 10,000 sheets were printed and evaluated as described below.

<Toner retention measurement method in charging brush>
During the evaluation, printing is stopped when 50 sheets, 5000 sheets, and 10000 sheets are printed, and the charged brush in the main body is observed from the direction of the hair tip, and the toner staying in the charged brush from the area occupied by the staying toner The amount was judged.
A: The staying toner area is smaller than 30% of the entire brush area.
B: The area of staying toner is 30 to 50% of the area of the entire brush.
C: The staying toner area is larger than 50% of the entire brush area.

<Charging brush contamination measurement method>
During the evaluation, printing was stopped when 10,000 sheets were printed, and the charged brush in the main body was taken out and observed after removing the staying toner by air blowing to determine the degree of contamination of the charged brush.
A: Dirt is not seen on the charging brush.
B: Some dirt is seen on a part of the charging brush.
C: The charging brush is extremely contaminated.

<Cleaning performance measurement method>
During the evaluation, a solid white image was output on the entire surface of LETTER-sized XEROX 4024 paper (manufactured by XEROX, 75 g / m ² ) when 50 sheets, 5,000 sheets, and 10,000 sheets were printed. The cleaning performance was evaluated from the image stain on the white image.
A: Dirt is not seen on the surface of the intermediate transfer member, and there is no defect on the image.
B: Slight dirt is observed on the surface of the intermediate transfer member and slight dirt is seen on the image, but this is not a problem level.
C: The surface of the intermediate transfer member is very dirty, and the image is stained.

  The obtained evaluation results are shown in Table 4.

<Examples 2 and 3>
The image evaluation was performed in the same manner as in Example 1 except that the image forming apparatus using the brush density and the brush diameter described in Table 3 was used. The evaluation results are shown in Table 4.

<Examples 4 and 5>
The same procedure as in Example 1 was used except that the toner shown in Table 3 was used instead of the toner (1) of Example 1 and the image forming apparatus using the brush density and brush diameter shown in Table 3 was used. The image evaluation described later was performed. The evaluation results are shown in Table 4.

<Examples 6 to 13>
The image evaluation was performed in the same manner as in Example 1 except that the toner shown in Table 3 was used instead of the toner (1) in Example 1. The evaluation results are shown in Table 4.

<Comparative Examples 1, 3 to 7>
The image evaluation was performed in the same manner as in Example 1 except that the toner shown in Table 3 was used instead of the toner (1) in Example 1. The evaluation results are shown in Table 4.

<Comparative example 2>
The same procedure as in Example 1 was used except that the toner shown in Table 3 was used instead of the toner (1) of Example 1 and the image forming apparatus using the brush density and brush diameter shown in Table 3 was used. The image evaluation was performed. The evaluation results are shown in Table 4.

It is explanatory drawing of an example of the image forming apparatus of this invention. It is explanatory drawing of an example of the apparatus which measures the volume resistance value in this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Charging roller 3 Exposure apparatus 4 Developing apparatus 5 Primary transfer roller 6 Cleaning apparatus 7 Fixing apparatus 30 Intermediate transfer belt 31 Pickup roller 32 Secondary transfer roller 33 Charging roller 34 Charging brush 35 Paper conveyance belt 36 Paper discharge part 11 Lower part Electrode 12 Upper electrode 14 Ammeter 15 Constant voltage device 17 Measurement sample 18 Guide ring d Measurement sample thickness A Volume resistance measurement cell

Claims (4)

The formation of a toner image on the first image carrier and the primary transfer of the toner image onto the second image carrier are repeated for a plurality of color toner images, and a plurality of colors are formed on the second image carrier. An image forming method for forming a color image by superimposing the plurality of toner images on a transfer material at once,
The Grant charge by a charging brush against the remaining residual toner on said after the secondary transfer second image bearing member, is transferred to the first image bearing member from said second image carrier And a step of recovering the toner transferred onto the first image carrier from the second image carrier with a cleaning device for cleaning the first image carrier ,
A front Symbol charging bristle density of the brush 1.0 × 10 ⁷ to 1.0 × 10 ⁹ (present / m ^2),
Mean diameter I ([mu] m) is 10 to 70 ([mu] m) Der hair single prior Symbol charging brush is,
The toner has toner particles and fatty acid metal salt,
The fatty acid metal salt is externally added in an amount of 0.05 to 0.50 parts by mass with respect to 100.00 parts by mass of toner particles .
Before SL or less 25.0% free rate is 1.0% or more from the toner of the fatty acid metal salt,
An image forming method characterized by satisfying a relationship of 0.15 ≦ D50s ≦ 1.00 when a volume-based median diameter (D50) of the fatty acid metal salt is D50s (μm).   The image forming method according to claim 1, wherein the D50s satisfies a relationship of 0.15 ≦ D50s ≦ 0.75. When the 5% cumulative diameter on the volume basis of the fatty acid metal salt is D5s and the 95% cumulative diameter on the volume basis is D95s, the span value A defined by the following formula (1) is 1.75 or less. The image forming method according to claim 1, wherein the image forming method is an image forming method.
Span value A = (D95s−D5s) / D50s (1) Formula The image forming method according to any one of claims 1 to 3, wherein the liberation percentage of the toner of the fatty acid metal salt is 20.0% or more and 2.0% or less.

Images