JP2016177043A - Manufacturing device of toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing device of toners capable of effectively eliminating VOC (volatile organic compounds) from a dry gas discharged from an upper part of a fluidized bed drying machine.SOLUTION: A manufacturing device 10 of the toners dehydrates slurry containing toner base particles obtained by a wet method, and after that, the obtained dehydrated cake is dried by a fluidized bed drying machine 18. The manufacturing device 10 of the toners includes: a dehumidifier 28 for dehumidifying a dried gas discharged from the upper part of the fluidized bed drying machine 18; a heater 24 for heating the dried gas dehumidified by the dehumidifier 28; and a push-in blower 22 for feeding the dried gas heated by the heater 24 to the lower part of the fluidized bed drying machine 18. An upper space 18b of the inner part of the fluidized bed drying machine 18 is installed with active charcoal 60.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an apparatus for producing an electrostatic charge image developing toner used in an image forming apparatus such as an electrophotographic copying machine or a printer.

  The electrostatic image developing toner is used in image forming apparatuses such as printers, copiers, and facsimiles. Generally, the toner for developing an electrostatic image is produced by a wet method such as a suspension polymerization method, an emulsion polymerization aggregation method, or a dissolution suspension method. The suspension polymerization method is a method for producing toner particles by dispersing a composition containing a polymerizable monomer, a polymerization initiator, a colorant and the like in an aqueous medium and then polymerizing the composition. In the emulsion polymerization aggregation method, polymer primary particles are obtained by adding a polymerizable monomer to an aqueous medium containing a polymerization initiator and an emulsifier and stirring. Next, a colorant and, if necessary, a charge control agent are added thereto to agglomerate the polymer primary particles. Then, the obtained aggregate particles are aged to produce toner particles. In the dissolution suspension method, a solution phase obtained by dissolving a binder resin in an organic solvent and then adding a colorant or the like is dispersed by a mechanical shearing force in an aqueous phase containing a dispersant or the like. In this method, droplets are formed and an organic solvent is removed from the droplets to produce toner particles.

  The toner obtained by the wet method contains water and is in the form of a slurry. The slurry toner is subjected to steps such as dehydration and washing, and then dried by a dryer. As a dehydrator for dehydrating the slurry toner, for example, a filter press device is used. As a dryer for drying the cake obtained by dehydration, for example, a fluidized bed dryer is used (see Patent Document 1).

  In a conventional toner production apparatus, a dehydrated cake obtained by dehydrating slurry toner is placed in the middle stage of a fluidized bed dryer. In the lower part of the fluidized bed dryer, drying gas for drying the charged dehydrated cake is blown. As the drying gas for drying the dehydrated cake, for example, air heated to 40 to 55 ° C., nitrogen gas, or a mixed gas thereof is used. When the drying gas is blown into the lower part of the fluidized bed dryer, a fluidized bed is formed inside the fluidized bed dryer, and efficient contact and stirring between the dehydrated cake and the drying gas are performed. Moisture contained in the dewatered cake is discharged from the upper part of the fluidized bed dryer accompanying the drying gas.

JP 2001-134016 A

  In the toner manufacturing process, a volatile organic compound (VOC) such as toluene or benzene may be used as a solvent. Since VOC may cause pollution such as photochemical smog when released into the environment, the amount of VOC in toner shipped as a product is strictly regulated so as to be a predetermined value or less.

  VOC contained in the toner is removed to some extent together with moisture in the toner by drying the toner with a fluidized bed dryer. Since VOC in the toner is harder to remove than moisture, it is necessary to dry the toner for a long time with a fluidized bed dryer in order to keep the VOC amount in the toner below a predetermined value.

  However, if the time for drying the toner by the fluidized bed dryer becomes long, the VOC removal efficiency is lowered. This is because the dry gas discharged from the upper part of the fluidized bed dryer is dehumidified by the dehumidifier and then sent again to the lower part of the fluidized bed dryer, so that the VOC concentration in the dry gas gradually increases and the This is because the difference between the VOC concentration and the VOC concentration in the dry gas is reduced, and a concentration gradient sufficient to transfer the VOC component from the toner to the dry gas cannot be obtained.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a toner manufacturing apparatus capable of efficiently removing VOC from dry gas discharged from the upper part of a fluidized bed dryer. .

The present invention is as follows.
A toner production apparatus for producing a toner by dehydrating a slurry containing toner mother particles obtained by a wet method with a dehydrator and then drying the obtained dehydrated cake with a fluidized bed dryer,
A dehumidifier for dehumidifying the dry gas discharged from the upper part of the fluidized bed dryer;
A heater for heating the dry gas dehumidified by the dehumidifier;
A pushing blower for feeding the drying gas heated by the heater to the lower part of the fluidized bed dryer,
An apparatus for producing toner, wherein activated carbon is installed in an upper space inside the fluidized bed dryer.

Inside the fluidized bed dryer, a bag filter is installed,
The activated carbon is preferably installed above the bag filter.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing apparatus of the toner which can remove VOC efficiently from the dry gas discharged | emitted from the upper part of a fluidized bed dryer can be provided.

FIG. 3 is a flowchart of a toner manufacturing apparatus.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The toner manufacturing apparatus according to the present embodiment is an apparatus for manufacturing an electrostatic charge image developing toner used in electrophotography, electrostatic photography, and the like.

FIG. 1 is a process flow diagram of a toner manufacturing apparatus according to the present embodiment.
As shown in FIG. 1, the toner manufacturing apparatus 10 includes a storage hopper 12, a screw feeder 14, a rotary valve 16, a fluidized bed dryer 18, a bag filter 20, a pushing blower 22, a heater 24, a suction blower 26, and a dehumidifier. 28, an air inlet 30, a first gas filter 32, a second gas filter 34, and the like.

  Slurry toner obtained by a wet method such as a suspension polymerization method, a dissolution suspension method, or an emulsion polymerization method is first dehydrated to a water content of about 25% by a dehydrator such as a filter press to form a cake. Then, it is stored in the storage hopper 12. The cake-like toner (dehydrated cake) stored in the storage hopper 12 is discharged from the lower portion of the storage hopper 12 while being pulverized by the screw feeder 14. The dewatered cake discharged by the screw feeder 14 is fed into the middle stage portion 18a of the fluidized bed dryer 18 by a predetermined amount by the rotary valve 16. The rotational speed of the rotary valve 16 is variable, and the supply speed of the dehydrated cake put into the fluidized bed dryer 18 can be controlled by the rotary valve 16.

In the lower part of the fluidized bed dryer 18, a plate plate 36 is installed, and the plate plate 36 is provided with a number of holes. The toner dehydrated cake charged into the middle stage 18 a of the fluidized bed dryer 18 is deposited on the upper part of the countersink plate 36. Then, a dry gas heated to, for example, about 40 to 55 ° C. is blown from below the eye plate plate 36, thereby forming a fluidized layer of toner on the upper portion of the eye plate plate 36. As a result, contact and stirring of the toner and the drying gas are simultaneously performed, so that the toner can be efficiently dried. As a drying gas for drying the dehydrated cake, for example, air, nitrogen, or a mixed gas thereof is used. Drying air is taken into the system via the atmospheric inlet 30. Nitrogen for drying can be supplied into the system from a nitrogen supply source such as a PSA nitrogen generator, a membrane separation nitrogen generator, or a nitrogen cylinder.
Such fluidized bed dryers are known and disclosed in, for example, Japanese Patent Application Laid-Open Nos. 2001-134016 and 11-344831.

A bag filter 20 is installed above the inside of the fluidized bed dryer 18. The bag filter 20 includes a plurality of cylindrical filter cloths 20a. The plurality of cylindrical filter cloths 20 a are installed in a state of being suspended inside the fluidized bed dryer 18. The plurality of cylindrical filter cloths 20a can separate the dry gas discharged from the upper part of the fluidized bed dryer 18 from the powdered toner.
In addition, a backwash device (not shown) that can blow air, nitrogen, or a mixed gas thereof into the inside of the cylindrical filter cloth 20a is installed on the upper portion of the bag filter 20. With this backwash device, the toner adhering to the surface of the filter cloth 20a can be dropped intermittently downward.

  The pushing blower 22 is a device for sending the drying gas into the lower part of the fluidized bed dryer 18. In the present embodiment, a turbo fan is used for the pushing blower 22. A damper 38 is installed on the suction side of the pusher blower 22. A damper 39 is installed on the discharge side of the pushing blower 22.

  Further, a heater 24 and a first gas filter 32 are installed on the discharge side of the push blower 22. The dry gas pushed by the pushing blower 22 is heated to, for example, about 40 to 55 ° C. by the heater 24, and then small foreign matters such as dust are removed by the first gas filter 32. The dry gas that has passed through the first gas filter 32 is sent to the lower part of the fluidized bed dryer 18. As the heater 24, for example, a plate fin tube heat exchanger can be used. As the heating medium of the heater 24, for example, steam can be used.

  The suction blower 26 is a device for sucking dry gas from the upper part of the fluidized bed dryer 18. In the present embodiment, a turbo fan is used for the suction blower 26. Two dampers 40 and 42 are installed on the suction side of the suction blower 26.

  The number of rotations of the pusher blower 22 and the suction blower 26 is variable by an inverter. By controlling the rotational speeds of the push blower 22 and the suction blower 26, the flow rate of the drying gas supplied to the lower part of the fluidized bed dryer 18 can be controlled.

  A dehumidifier 28 and a second gas filter 34 are installed between the suction blower 26 and the bag filter 20. The dry gas sucked from the upper part of the fluidized bed dryer 18 by the suction blower 26 is sent to the dehumidifier 28 after the fine powder of toner is removed by the second gas filter 34. The dry gas sent to the dehumidifier 28 is dehumidified by being cooled to 8 to 16 ° C., for example. As the dehumidifier 28, for example, a plate fin tube heat exchanger can be used. As the cooling medium of the dehumidifier 28, for example, water can be used.

  All or a part of the drying gas sucked from the upper part of the fluidized bed dryer 18 by the suction blower 26 circulates in the system through the circulation line 45. That is, all or part of the dry gas sucked by the suction blower 26 passes through the circulation line 45 and is then sent again to the lower part of the fluidized bed dryer 18 by the push blower 22.

  On the discharge side of the pusher blower 22, a discharge duct 51 is provided for discharging excess system gas to the outside according to the pressure inside the fluidized bed dryer 18. The discharge duct 51 is provided with a valve 52. By opening the valve 52, it is possible to release excess gas in the system, and the pressure inside the fluidized bed dryer 18 can be controlled to be constant.

  A nitrogen supply duct 53 is provided on the discharge side of the pusher blower 22 to supply nitrogen gas into the system in which the dry gas circulates. The nitrogen supply duct 53 is provided with a valve 54. By this valve 54, the oxygen concentration of the dry gas circulating in the system can be controlled to a predetermined value or less. Further, by controlling the oxygen concentration of the drying gas to a predetermined value or less, it is possible to prevent a dust explosion from occurring inside the fluidized bed dryer 18.

  When it is necessary to replace the interior of the system with air during cleaning or maintenance of the toner manufacturing apparatus 10, the damper 55 installed in the circulation line 45 is closed, the intake damper 38 is opened, and the exhaust damper 56 is opened. open. Thereby, since the flow of the dry gas in the system is changed from the circulation path to one path, the dry gas in the system can be replaced by the external air.

  As described above, the toner manufacturing apparatus 10 of the present embodiment heats the dehumidifier 28 for dehumidifying the dry gas discharged from the upper part of the fluidized bed dryer 18, and the dry gas dehumidified by the dehumidifier 28. And a pusher blower 22 for feeding the drying gas heated by the heater 24 to the lower part of the fluidized bed dryer 18. And the activated carbon 60 for removing VOC (volatile organic compound) contained in dry gas is installed in the upper space 18b inside the fluidized bed dryer 18.

  The drying gas discharged from the upper part of the fluidized bed dryer 18 circulates in the system connecting the upper part and the lower part of the fluidized bed dryer 18. For this reason, when the VOC contained in the dry gas is not removed, the VOC concentration in the dry gas gradually increases.

  In the conventional toner production apparatus 10, it has been considered to install activated carbon for removing VOC at the outlet side of the dehumidifier 28 in order to remove VOC from the dry gas circulating in the system. This is because, on the outlet side of the dehumidifier 28, the temperature of the dry gas is low, so that it is considered that the adsorption ability of the activated carbon is more effectively exhibited.

However, the present inventor has found that there is the following problem when activated carbon is installed on the outlet side of the dehumidifier 28.
(1) A drain pipe for discharging moisture removed from the dry gas is provided inside the dehumidifier 28. The drain pipe may be clogged with fine toner powder or the like. When the drain pipe is clogged, water accumulates inside the dehumidifier 28. When water accumulates inside the dehumidifier 28, the activated carbon installed on the outlet side of the dehumidifier 28 gets wet by water droplets accompanying the dry gas, and VOC contained in the dry gas is effectively removed. You will not be able to.
(2) Due to the structure of the dehumidifier 28, there is almost no space where activated carbon can be installed on the outlet side of the dehumidifier 28. For this reason, when installing activated carbon in the exit side of the dehumidifier 28, you have to manufacture the box for exclusive use for installing activated carbon. Therefore, the cost increases as much as the dedicated box is manufactured and installed.
(3) Since an inspection port (manhole) for an operator to enter is not provided on the outlet side of the dehumidifier 28, it is extremely difficult to replace the activated carbon installed in the dehumidifier 28.

  As a result of examining the installation location of the activated carbon for removing VOC, the present inventor has surprisingly found that the upper space 18b inside the fluidized bed dryer 18 is suitable.

  The upper space 18b inside the fluidized bed dryer 18 was considered to be unsuitable as a place for installing activated carbon because the temperature of the drying gas was high. That is, it is common technical knowledge that the adsorption ability of activated carbon increases as the temperature of the gas to be adsorbed decreases. Therefore, from the conventional technical common sense, the upper space 18b inside the fluidized bed dryer 18 is a place that is considered unsuitable as a place for installing activated carbon, and is a place that could not be conceived by those skilled in the art. is there.

  The present inventor has discovered that by installing the activated carbon 60 in the upper space 18b inside the fluidized bed dryer 18, the VOC concentration of the dry gas circulating in the system can be reduced as in the conventional case. The reason why such an effect is obtained by the present invention is not clear, but the upper space 18b inside the fluidized bed dryer 18 has a high temperature of the drying gas but a low relative humidity. It is presumed that the adsorption capacity is effectively exhibited and the decrease in adsorption capacity due to increase in adsorption temperature is offset.

  The type and shape of the activated carbon 60 are not particularly limited, and for example, activated carbon in a fibrous, honeycomb, cylindrical pellet, crushed, granular, or powder form can be used.

  The installation method of the activated carbon 60 is not particularly limited, and any method may be used. For example, the activated carbon 60 may be stored in a net-like container, and the container may be installed so as to be suspended in the upper space 18 b inside the fluidized bed dryer 18. Alternatively, the activated carbon 60 formed in a sheet shape may be installed so as to be suspended in the upper space 18 b inside the fluidized bed dryer 18.

A bag filter 20 for separating the toner from the dry gas is installed on the upper part of the fluidized bed dryer 18.
An inspection port 62 (manhole) for performing maintenance or replacement of the filter cloth 20a of the bag filter 20 is installed on the ceiling 18c on the upper surface of the fluidized bed dryer 18.

  According to the toner manufacturing apparatus 10 of the present embodiment, an operator can enter the inside of the fluidized bed dryer 18 by using the existing inspection port 62 provided in the fluidized bed dryer 18. For this reason, it is very easy to install and replace the activated carbon 60 in the fluidized bed dryer 18.

  Further, according to the toner manufacturing apparatus 10 of the present embodiment, since the activated carbon 60 is installed in the space above the bag filter 20, the space above the bag filter 20, which has conventionally been a dead space, is effectively used. can do.

  In addition, a sufficient space for installing the activated carbon 60 is secured above the bag filter 20, so that it is not necessary to manufacture and install a dedicated box for installing the activated carbon 60. Costs for manufacturing and installing boxes can be reduced.

  As described above, according to the toner manufacturing apparatus 10 of the present embodiment, VOC can be efficiently and cost-effectively removed from the dry gas discharged from the upper part of the fluidized bed dryer 18. .

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the following examples, “parts” means parts by mass. In addition, the live-action test was conducted by the following method. Further, the particle diameter, circularity, electrical conductivity, etc. of the toner were measured as follows.

<Volume average diameter measurement (Mv)>
The volume average diameter (Mv) of polymer primary particles having a volume average diameter (Mv) of less than 1 μm is measured by Nikkiso Co., Ltd. Model Microtrac Nanotrac 150 (hereinafter abbreviated as “Nanotrack”) and analysis software Microtrac Particle Analyzer Ver10.1.2-019EE Using the ion exchange water having an electric conductivity of 0.5 μS / cm as a solvent, the refractive index of the solvent: 1.333, the measurement time: 600 seconds, the number of measurements: 1 The measurement was performed by the method described in the instructions. Other setting conditions were particle refractive index: 1.59, transparency: transmission, shape: true sphere, density: 1.04.

<Volume median diameter of wax dispersion>
In order to determine the end point at the time of wax emulsification, the median diameter measured using Partica LA-950V2 (hereinafter abbreviated as LA950) manufactured by HORIBA, Ltd., which is a laser diffraction scattering type particle size distribution measuring apparatus capable of high-speed measurement, is determined as the end particle size. It was. Using ion-exchanged water having an electric conductivity of 0.5 μS / cm as a solvent, the sample amount was adjusted so as to be in a concentration range of solvent refractive index: 1.333 and visible light transmittance of 70% to 90%, and emulsified. The wax particle size was measured.

<Measurement method and definition of median diameter (volume: Dv50 and number: Dn50)>
As a pre-measurement treatment of the toner finally obtained through the external addition process, it was performed as follows. In a cylindrical polyethylene (PE) beaker having an inner diameter of 47 mm and a height of 51 mm, 0.100 g of toner using a spatula, and 20% by weight DBS (sodium dodecylbenzenesulfonate) aqueous solution using a dropper (Daiichi Kogyo Seiyaku Co., Ltd.) 0.15 g manufactured by Neogen S-20A) was added. At this time, toner and a 20% DBS aqueous solution were added only to the bottom of the beaker so that the toner would not scatter on the edge of the beaker. Next, the mixture was stirred for 3 minutes using a spatula until the toner and 20% DBS aqueous solution became a paste. At this time, the toner was prevented from being scattered on the edge of the beaker.

  Subsequently, 30 g of dispersion medium Isoton II was added, and the mixture was stirred for 2 minutes using a spatula to obtain a uniform solution as a whole. Next, a fluororesin-coated rotor having a length of 31 mm and a diameter of 6 mm was placed in a beaker and dispersed using a stirrer at 400 rpm for 20 minutes. At this time, using a spatula at a rate of once every 3 minutes, macroscopic particles visually observed at the gas-liquid interface and the edge of the beaker were dropped into the beaker so as to form a uniform dispersion. Subsequently, this was filtered through a mesh having an opening of 63 μm, and the obtained filtrate was designated as “toner dispersion”. Regarding the measurement of the particle diameter during the production process of the toner base particles, the filtrate obtained by filtering the agglomerated slurry with a 63 μm mesh was used as the “slurry liquid”.

  The median diameter of the particles (Dv50 and Dn50) is Beckman Coulter Multisizer III (aperture diameter 100 μm) (hereinafter abbreviated as “Multisizer”), the dispersion medium is Isoton II, and the above-mentioned The “toner dispersion liquid” or “slurry liquid” is diluted so that the dispersoid concentration becomes 0.03% by mass, and the KD value is 118. Measured as 5. The measurement particle diameter range is from 2.00 to 64.00 μm, and this range is discretized into 256 divisions so as to be equidistant on a logarithmic scale, and the volume calculated based on the statistical values on the basis of the volume is the volume. The median diameter (Dv50) and the value calculated based on the statistical value on the basis of the number were defined as the number median diameter (Dn50).

<Measuring method and definition of average circularity>
The “average circularity” in the present invention is measured as follows and is defined as follows. That is, the toner base particles are dispersed in a dispersion medium (Isoton II, manufactured by Beckman Coulter, Inc.) in a range of 5720 to 7140 particles / μL, and a flow type particle image analyzer (manufactured by Sysmex Corporation, FPIA3000) is used. Measured under the following apparatus conditions, the value is defined as “average circularity”. In the present invention, the same measurement is performed three times, and an arithmetic average value of three “average circularity” is adopted as the “average circularity”.
・ Mode: HPF
-HPF analysis amount: 0.35 μL
・ Number of HPF detections: 8,000 to 10,000

The following is measured by the device and automatically calculated and displayed in the device, and “circularity” is defined by the following equation.
[Circularity] = [Perimeter of a circle with the same area as the projected particle area] / [Perimeter of projected particle image]
Then, the number of HPF detected is 8,000 to 10,000, and the arithmetic average (arithmetic mean) of the circularity of each particle is displayed on the apparatus as “average circularity”.

<Measuring method of glass transition temperature>
Using a differential scanning calorimeter DSC 6220 manufactured by Seiko Instruments Inc., the monomer component constituting the binder resin was measured under the condition of a temperature rising rate of 10 ° C./min. The glass transition temperature was obtained from the intersection of the extension line of the DSC curve base line and the tangent line showing the maximum inclination in the endothermic curve, using analysis software (Muse standard analysis software) attached to the apparatus. Further, when measuring the glass transition temperature of the toner base particles, when the glass transition temperature cannot be clearly determined due to a change in the amount of heat of other components other than the resin, such as wax, Instead of adopting the theoretical glass transition temperature, measurement was performed on components (monomer components constituting the binder resin) excluding components such as waxes that obstruct measurement of the differential scanning calorimeter.

Example 1
<Adjustment of colorant dispersion>
Carbon black produced by a furnace method with a toluene extract of 0.02 and a true density of 1.8 g / cm 3 in a container of a stirrer equipped with a propeller blade (manufactured by Mitsubishi Chemical Corporation, Mitsubishi Carbon Black) MA100S) 20 parts, anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen S-20D) 1 part, nonionic surfactant (manufactured by Kao Corporation, Emulgen 120) 4 parts, ion with conductivity 1 μS / cm 75 parts of exchange water was added and predispersed to obtain a pigment premix solution. The volume cumulative 50% diameter Dv50 of the carbon black in the dispersion after the premix was about 90 μm. The premix solution was supplied as a raw material slurry to a wet bead mill and subjected to one-pass dispersion. Note that zirconia beads (true density 6.0 g / cm 3) having a diameter of 120 mmφ, a separator diameter of 60 mmφ, and a diameter of 50 μm were used as a dispersion medium. Since the effective internal volume of the stator is about 2 liters and the media filling volume is 1.4 liters, the media filling rate is 70%. When the rotational speed of the rotor is constant (the peripheral speed at the tip of the rotor is about 11 m / sec), the premix slurry is supplied from the supply port by a non-pulsating metering pump at a supply speed of about 40 liters / hr, and reaches a predetermined particle size. The product was acquired from the outlet. During operation, cooling water at about 10 ° C. was circulated from the jacket to obtain a colorant dispersion.

<Preparation of wax dispersion A1>
As a wax, HiMic-1090 (manufactured by Nippon Seiwa Co., Ltd .: melting point 89 ° C.) 28.5 parts, decaglycerin decabehenate (acid value 3.2, hydroxyl value 27) 1.5 parts, 20% DBS (dodecylbenzenesulfonic acid) Sodium) aqueous solution (Daiichi Kogyo Seiyaku Co., Ltd., Neogen S20D, hereinafter abbreviated as 20% DBS aqueous solution) 2.8 parts and 67.3 parts of demineralized water were added and heated to 100 ° C., and a homogenizer with a pressure circulation line ( Primary circulation emulsification was performed under a pressure of 10 MPa using a LAB 60-10TBS type manufactured by Gorin. The particle diameter is measured every few minutes with LA950, and when the median diameter is reduced to around 500 nm, the pressure condition is further increased to 25 MPa, followed by secondary circulation emulsification. A wax dispersion A1 was produced by dispersing until the median diameter was 230 nm or less. The volume median diameter of the wax dispersion was 220 nm.

<Preparation of polymer primary particle dispersion B1>
In a reactor equipped with a stirring device (three blades), a heating / cooling device, a concentrating device, and each raw material / auxiliary charging device, the wax dispersion A1: 35.7 parts (182.0 kg), demineralized water 259 parts Was heated to 90 ° C. under a nitrogen stream while stirring.
Thereafter, the mixture of the following “polymerizable monomers and the like” and “emulsifier aqueous solution” was added to the solution over 5 hours while continuing to stir the liquid. The time at which this mixture was started to be dropped was designated as “polymerization start”, and the following “initiator aqueous solution” was added over 4.5 hours from 30 minutes after the start of polymerization. Further, after 5 hours from the start of polymerization, the following “additional start” The agent aqueous solution ”was added over 2 hours, and the polymerization reaction was continued for 1 hour while maintaining the internal temperature at 90 ° C. while continuing the stirring. The design glass transition temperature (Tg) of the binder resin obtained from the following polymerizable monomers was designed to be 56.0 ° C. The design glass transition temperature (Tg) of the binder resin is a value that is arithmetically derived from the weight fraction (mass ratio) of the main monomers constituting the binder resin, and was calculated as in the following formula (3). . Here, main monomers constituting the binder resin are styrene and butyl acrylate.
Design glass transition temperature (Tg) of binder resin = glass transition temperature of styrene alone (° K) × mass% of styrene in the total amount of styrene and butyl acrylate + glass transition temperature of butyl acrylate alone (° K) × Mass% of butyl acrylate in the total amount of styrene and butyl acrylate (3)

[Polymerizable monomers, etc.]
Styrene 76.3 parts Butyl acrylate 23.7 parts Acrylic acid 1.5 parts Hexanediol diacrylate 0.7 parts Trichlorobromomethane 1.0 part

  After completion of the polymerization reaction, the mixture was cooled to obtain a milky white polymer primary particle dispersion B1. The volume average diameter (Mv) measured using Nanotrac was 277 nm, and the solid content concentration was 22.7% by mass.

<Manufacture of toner mother particle C1>
Using the following components, toner base particles C1 were produced by carrying out the following aggregation process (core material aggregation process / shell coating process) / circularization process.

Polymer primary particle dispersion B1 80 parts as solid content (Dispersion B1: 280.0 kg / solid content: 63.3 kg for core)
Polymer primary particle dispersion B1 20 parts as solid content (dispersion B1: 70.0 kg / solid content: 15.8 kg for shell)
Colorant fine particle dispersion 6.0 parts as a colorant solid content 20% DBS aqueous solution 6 parts as a solid content in the rounding step

○ Core material agglomeration step Polymer primary particle dispersion B1 is charged into a mixer (volume 1000 L, inner diameter 850 mm) equipped with a stirrer (double helical blade), heating / cooling device, and raw material / auxiliary charging device, and the internal temperature is 10 Mix uniformly at 10 ° C. for 10 minutes. Subsequently, at an internal temperature of 10 ° C. and 101 rpm, a 5 mass% aqueous solution of potassium sulfate was continuously added as K2SO4 over 0.12 parts over 1 minute, and then the colorant fine particle dispersion was continuously applied over 5 minutes. The mixture was added and mixed uniformly at an internal temperature of 10 ° C.
Thereafter, 0.3 part by weight of an aqueous solution of 0.5% by mass of aluminum sulfate was continuously added over 30 minutes, and the internal temperature was raised to 48.0 ° C. over 70 minutes while maintaining the rotation speed at 101 rpm ( 0.5 ° C./min). Subsequently, after raising the temperature by 1 ° C. every 30 minutes (0.03 ° C./min), the temperature was maintained at 54.0 ° C., the volume median diameter was measured using a multisizer, and grown to 5.17 μm.

Shell coating step Thereafter, the polymer primary particle dispersion B1 was continuously added over 15 minutes while maintaining the internal temperature at 54.0 ° C. and the rotation speed of 101 rpm, and held as it was for 60 minutes. At this time, Dv50 of the particles was 5.51 μm.

○ Circularization step Subsequently, the mixture was heated to 90 ° C. while adding a mixed aqueous solution of 20% DBS aqueous solution (6 parts as solids) and 0.04 part of water over 30 minutes with the same rotation speed, and then The temperature was raised by 1 ° C. every 30 minutes, raised to 95 ° C., and heating and stirring were continued under these conditions until the average circularity reached 0.968 over 2.5 hours. Thereafter, the mixture was cooled to 20 ° C. over 50 minutes to obtain a slurry of toner base particles C1. At this time, the volume median diameter (Dv50) of the particles was 5.61 μm, the number median diameter (Dn50) was 5.23 μm, the distribution Dv50 / Dn50 was 1.07, and the average circularity was 0.967.

○ Washing process The obtained slurry is filtered for the purpose of removing coarse particles using a wet electromagnetic sieve shaker (AS200 / Lecche Co., Ltd.) equipped with a sieve having a mesh size of 24 μm and equipped with a stirrer. Once stored in the tank. After that, the slurry was applied to a horizontal centrifuge (HZ40Si type / Mitsubishi Chemical Corporation) equipped with a filter cloth (polyester TR815C, Nakao filter industry / thickness 0.3 mm / air permeability 48 (cc / cm 2 / min)). Then, centrifugal dehydration washing was performed under the condition of acceleration 800G. When ion-exchanged water having an electric conductivity of 1 μS / cm was added at about 60 times the amount of slurry solids at a rate not overflowing from the rim, the electric conductivity of the filtrate was 2 μS / cm. Finally, water was thoroughly shaken off, and the cake was recovered with a scraping device.

○ Drying process The cake obtained in the washing process is put into a fluidized bed dryer: AGM-35PJ type (manufactured by Hosokawa Micron Corporation) and dried for 180 minutes using 40 ° C. dry nitrogen gas heated by a heater, and toner base particles C1 Got. At that time, 150 g of activated carbon ZX-9 (manufactured by Calgon Carbon Japan) was filled into the space above the bag filter of the dryer in a container made of a SUS304 cubic frame with a 1.4 mm square polyethylene net. A total of 5 objects were hung at equal intervals.
The water content of the obtained toner was less than 0.2% as measured with a Karl Fischer moisture meter.
Volatile organic compounds emitted from the toner base particles C1 were measured by the following method.

<Measurement method of volatile organic compounds>
Put toner base particle C1 in a 20 mL glass sample bottle, seal the main body and lid of the sample bottle with sealing tape, and then put it in a bag (Lami Zip; manufactured by Seinichi Co., Ltd.) to change the amount of volatile organic compounds in the gas. After 4 days in this state, elute between n-hexane and n-hexadecane on a non-polar column for gas chromatography by headspace gas chromatography mass spectrometry according to the following measurement procedure. Among the volatile organic compounds, the benzaldehyde concentration, the styrene concentration and the ethylbenzene concentration converted using the toluene concentration and the toluene correction coefficient measured with the following mixed standard sample were measured. Furthermore, the concentration obtained by converting the peak area of a volatile organic compound identified between n-hexane and n-hexadecane measured by headspace gas chromatography mass spectrometry using a toluene correction coefficient, and for gas chromatography The total volatile organic compound (Total-) represented by the sum of the peak area of the volatile organic compound not identified between n-hexane and n-hexadecane on the nonpolar column and the concentration converted using the toluene correction factor The concentration of VOC) was measured.

  The measurement procedure is as follows. Toner mother particles C1: 0.5 g was weighed into a 20 mL headspace (HS) vial (Chromacol 20-CV), and then the vial was capped (cap: Chromacol 20-MCB 224, PTEF / silicone septum: GL Sciences 20- ST3). The vial was placed in an oven set at 180 ° C. (agitator attached to MPS manufactured by GERSTEL), heated for 10 minutes while rotating at 750 rpm, and then the gas in the gas phase in the vial was injected into GC (gas chromatography), and the head Space gas chromatograph (HS-GC / MS) measurement was performed. Here, an empty vial not filled with the sample was processed in the same manner to obtain a blank.

A mixed standard solution of about 1,000 μg / mL of benzene, toluene, ethylbenzene, m-xylene, styrene, n-hexane, n-hexadecane, n-hexanal, n-heptanal, n-octanal and benzaldehyde using acetone as a solvent. Was prepared, capped with 1, 2, and 4 μL of this standard solution in 20 mL headspace vials, respectively, and then HS-GC / MS measurement was performed in the same manner as the sample. The results are shown in Table 1. In addition, the manufacturer and grade of each reagent are shown below. Benzaldehyde concentration converted from this mixed standard solution using a toluene correction factor, styrene concentration converted using a toluene correction factor, ethylbenzene concentration converted using a toluene correction factor, and n-hexane to n -It is not identified between the concentration obtained by converting the peak area of the volatile organic compound identified up to hexadecane using the toluene correction factor and n-hexane to n-hexadecane on the non-polar column for gas chromatography. The concentration of the total volatile organic compound (Total-VOC) indicated by the sum of the peak area of the volatile organic compound and the concentration converted using the toluene correction coefficient was measured.
(1) Acetone: Wako Pure Chemical Industries, reagent special grade (2) Benzene: Wako Pure Chemical Industries, residual agricultural chemical test (3) Toluene: Wako Pure Chemical Industries, residual brain abbreviation / PCB test (4) Ethylbenzene : ACROS ORGANICS, reagent grade (5) m-xylene: manufactured by Kanto Chemical Co., Ltd., reagent special grade (6) Styrene: manufactured by Wako Pure Chemical Industries, reagent special grade (7) n-hexane: manufactured by Wako Pure Chemical Industries, pesticide residue PCB test (8) n-hexadecane: manufactured by Wako Pure Chemical Industries, reagent special grade (9) n-hexanal: manufactured by Tokyo Chemical Industry Co., reagent grade (10) n-heptanal: manufactured by Tokyo Chemical Industry Co., Ltd., reagent grade (11) n-octanal: Wako Pure Chemical Industries, reagent grade 1 (12) benzaldehyde: Nacalai Tesque, reagent grade

<Manufacture of developing toner D1: external addition process>
Toner toner particles C1: 2500 g obtained are mixed with 50 g of Clariant H05TD silica and 15 g H30TD silica as external additives, mixed with a Henschel mixer (Mitsui Mine), sieved with 150 mesh, and developing toner. D1 was obtained.

(Example 2)
Although the same operation as in Example 1 was performed, the drain pipe was clogged in the dehumidifier during the operation, and water accumulated in the dehumidifier 28. Toner base particles C2 were obtained in the same manner as in Comparative Example 1 for toner base particles C2 obtained here, and the concentration of volatile organic compounds was measured by headspace gas chromatography mass spectrometry. Using this toner base particle C2, a developing toner D2 was obtained in the same manner as in Example 1.

(Comparative Example 1)
Except that activated carbon was installed at the outlet of the dehumidifier, toner mother particles C3 were obtained in the same manner as in Example 1, and the concentration of the volatile organic compound was measured by headspace gas chromatography mass spectrometry. Using this toner base particle C3, a developing toner D3 was obtained in the same manner as in Example 1.

(Comparative Example 2)
Although the same operation as Comparative Example 1 was performed, the drain piping was clogged in the dehumidifier during the operation, and water accumulated in the dehumidifier 28 and the activated carbon was submerged. Toner base particles C4 were obtained in the same manner as in Comparative Example 1 to obtain toner base particles C4, and the concentration of volatile organic compounds was measured by headspace gas chromatography mass spectrometry. Using the toner base particles C4, a developing toner D4 was obtained in the same manner as in Example 1.

(Comparative Example 3)
The gas in a glass beaker in which a commercially available toner R1 (OK1 Microline 9600PS manufactured by Mitsubishi Chemical Corporation) was allowed to stand was measured in the same manner as in Example 1 by headspace gas chromatography mass spectrometry.

(Comparative Example 4)
Gas in a glass beaker in which a commercially available toner R2 (manufactured by Konica Minolta, magigolor 5570) was allowed to stand in the same manner as in Example 1 was measured by headspace gas chromatography mass spectrometry.

(Comparative Example 5)
Gas in a glass beaker in which a commercially available toner R3 (manufactured by LEXMARK, C780) was allowed to stand in the same manner as in Example 1 was measured by headspace gas chromatography mass spectrometry.

  Table 1 shows the measurement results of Examples 1 and 2 and Comparative Examples 1 to 5.

  As shown in Table 1, the toner base particles of Example 1 are equivalent to the toner base particles of Comparative Example 1 in spite of an inexpensive apparatus configuration that does not require installation of a large box or the like for storing VOC. A VOC concentration of 10 μm was achieved.

  Further, in Example 2 and Comparative Example 2, there was a trouble that the drain pipe in the dehumidifier was clogged. In Comparative Example 2, although the VOC removal capability was lower than that in Comparative Example 1, trouble was caused in Example 2. It was possible to maintain the same VOC removal ability as when there was not.

  In addition, the toner base particles of Example 1 and Example 2 are reduced to about ½ compared to commercially available toners (Comparative Examples 3 to 4) that satisfy the specified values specified in the “Blue Angel” mark standard and the like. Total VOC was reduced, and among volatile organic compounds, the styrene concentration was reduced to a fraction of the concentration.

  From the results in Table 1, it was confirmed that a toner having a sufficiently reduced volatile organic compound containing styrene can be obtained even if it contains a styrene resin as the binder resin.

DESCRIPTION OF SYMBOLS 10 Toner production apparatus 12 Storage hopper 18 Fluidized bed dryer 18b Upper space 20 Bag filter 22 Push blower 24 Heater 26 Suction blower 28 Dehumidifier 30 Air inlet 32 First gas filter 34 Second gas filter 45 Circulation line 60 Activated carbon 62 Inspection port

Claims (2)

A toner production apparatus for producing a toner by dehydrating a slurry containing toner mother particles obtained by a wet method with a dehydrator and then drying the obtained dehydrated cake with a fluidized bed dryer,
A dehumidifier for dehumidifying the dry gas discharged from the upper part of the fluidized bed dryer;
A heater for heating the dry gas dehumidified by the dehumidifier;
A pushing blower for feeding the drying gas heated by the heater to the lower part of the fluidized bed dryer,
An apparatus for producing toner, wherein activated carbon is installed in an upper space inside the fluidized bed dryer. Inside the fluidized bed dryer, a bag filter is installed,
The toner production apparatus according to claim 1, wherein the activated carbon is installed above the bag filter.

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