JP2016147225A - Apparatus and method for manufacturing fine particle, and toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for manufacturing fine particles, capable of preventing droplets from adhering to the wall surface of the apparatus and securing maintainability and achieving high productivity in the production of fine particles by injection granulation.SOLUTION: An apparatus for manufacturing fine particles comprises at least: droplet discharging means 11 for discharging a fine particle raw material containing liquid as droplets from at least one discharge hole; and conveying/solidifying means for conveying and solidify the droplets 21 discharged by the droplet discharging means 11 using a conveying air flow 70. The conveying/solidifying means comprises: a conveying flow passage 12 to be used as the flow passage of the droplets 21 and the conveying air flow 70; conveying air flow generating means for generating the conveying air flow 70; and auxiliary air flow generating means for generating an auxiliary air flow 71 flowing to the upstream side from the downstream side in the conveying direction of the droplets 21 along the wall surface of the conveying flow passage 12. The conveying flow passage 12 has an extension part 73 having a cross sectional area expanded toward the downstream side, and the auxiliary air flow 71 flows along the wall surface of the extension part 73.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fine particle production apparatus, a fine particle production method, and a toner.

As resin fine particles for which uniformity is required, toner for developing electrostatic images used in copying machines, printers, fax machines, and composite machines based on the electrophotographic recording method, spacer particles for liquid crystal panels, and colored fine particles for electronic paper In addition, fine particles and the like as drug carriers of pharmaceuticals are known.
As a method for producing such resin fine particles (particularly, toner for developing an electrostatic charge image), only the conventional pulverization method has been used, but recently, a polymerization method for forming fine particles in an aqueous medium has been widely performed.

The polymerization method involves the polymerization reaction of the fine particle raw material during or during the formation of fine particles. As a polymerization method, various polymerization methods have been put into practical use, and examples thereof include soap-free emulsion polymerization.
The polymerization method makes it easy to obtain fine particles having a small particle size, and the obtained fine particles generally have characteristics such as a narrow particle size distribution and a nearly spherical shape compared to those obtained by the pulverization method.

By using the toner obtained by the polymerization method, there is an advantage that a high-quality image can be easily obtained in the electrophotographic system.
However, the polymerization process requires a long time, and after solidifying, it is necessary to separate the solvent and toner particles, and then repeat washing and drying, which requires a lot of time, water, and energy. .

Therefore, a jet granulation method in which a fine particle material-containing liquid (hereinafter sometimes referred to as toner composition liquid) in which raw material components of toner are dissolved or dispersed in an organic solvent is finely divided and then dried to obtain a powdery toner. Has been proposed (see, for example, Patent Documents 1 and 2).
According to these proposals, it is not necessary to use water, and the steps such as washing and drying can be greatly reduced, so that the disadvantages of the polymerization method can be avoided, the production efficiency is very high, and the energy is saved. A toner having a narrow particle size distribution can be produced.

  However, in the manufacturing apparatus described in Patent Document 1, the discharged toner droplets may be decelerated due to the air resistance due to viscosity, and may be joined with the subsequent toner droplets. If the toner droplets that are coalesced and the toner droplets that are not coalesced are mixed in the gas phase, toner particles having different sizes may be produced, and uniformity may be impaired. In other words, long-time collection may lead to a problem that deteriorates the particle size distribution of the recovered particles.

  Moreover, in the manufacturing apparatus described in Patent Document 2, undried particles may adhere to the air channel wall surface, which may cause a decrease in maintainability. Moreover, since the particles adhering to the wall surface are not collected, the productivity is lowered accordingly.

  Accordingly, an object of the present invention is to provide a fine particle production apparatus capable of preventing droplets from adhering to the wall surface, ensuring maintenance, and realizing high productivity in the production of fine particles by spray granulation.

  In order to achieve such an object, a fine particle manufacturing apparatus according to the present invention includes a liquid droplet discharge unit that discharges a liquid containing a fine particle material as liquid droplets from at least one discharge hole, and a liquid droplet discharged by the liquid droplet discharge unit. Transport solidification means for transporting and solidifying by a transport airflow, wherein the transport solidification means is a transport flow path that serves as a flow path for the droplets and the transport airflow, and a transport airflow generation that generates the transport airflow. And an auxiliary airflow generating means for generating an auxiliary airflow that flows from the downstream side to the upstream side in the transport direction of the liquid droplets, and the transport channel has an extended portion whose cross-sectional area is expanded toward the downstream side. And the auxiliary airflow flows along a wall surface of the extension portion.

  ADVANTAGE OF THE INVENTION According to this invention, in manufacture of the microparticles | fine-particles by injection granulation, the adhesion to the wall surface of a droplet can be prevented, the microparticle manufacturing apparatus which can implement | achieve high productivity while ensuring maintenance property can be provided.

It is a schematic diagram which shows an example of a structure of the fine particle manufacturing apparatus of this embodiment. It is sectional drawing which shows an example of a droplet discharge means. It is sectional drawing of the discharge hole of a droplet discharge means. It is the schematic which shows the standing wave of the speed and pressure fluctuation in the case of N = 1, 2, 3 in a droplet discharge means. It is the schematic which shows the standing wave of the speed and pressure fluctuation in the case of N = 4 and 5 in a droplet discharge means. It is the schematic which shows the mode of the liquid column resonance phenomenon which arises in the liquid column resonance flow path of a droplet discharge means. It is a schematic diagram which shows the conveyance flow path cross section of the microparticle manufacturing apparatus concerning 1st embodiment. It is a schematic diagram which shows the conveyance flow path cross section of the microparticle manufacturing apparatus concerning 2nd embodiment. It is a schematic diagram which shows the conveyance flow path cross section of the microparticle manufacturing apparatus concerning 3rd embodiment. It is a schematic diagram which shows the conveyance flow path cross section of the microparticle manufacturing apparatus concerning 4th embodiment. It is a schematic diagram which shows the conveyance flow path cross section of the conventional fine particle manufacturing apparatus.

  Hereinafter, a fine particle production apparatus, a fine particle production method, and a toner according to the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below, and other embodiments, additions, modifications, deletions, and the like can be changed within a range that can be conceived by those skilled in the art, and any aspect is possible. As long as the functions and effects of the present invention are exhibited, the scope of the present invention is included.

The fine particle manufacturing apparatus according to the present embodiment includes a droplet discharge unit that discharges the liquid containing the fine particle raw material as droplets from at least one discharge hole, and the droplets discharged by the droplet discharge unit are transported by a transport airflow. And at least a conveying and solidifying means for solidifying, and further including other means as necessary.
Examples of other means include a liquid supply means for supplying the fine particle raw material-containing liquid to the droplet discharge means and a solidified fine particle collecting means for collecting the fine particles solidified by the transport solidifying means.
In addition, the fine particle manufacturing method according to the present embodiment includes a droplet discharge step of discharging a liquid containing a fine particle material as droplets from a droplet discharge unit having at least one discharge hole, and a liquid discharged in the droplet discharge step. A transport solidification step of transporting and solidifying the droplets by transport solidification means, and further including other steps as necessary.
Examples of the other steps include a liquid supply step for supplying the fine particle raw material-containing liquid to the droplet discharge means and a solidified fine particle collecting step for collecting fine particles solidified by the transport solidifying means.

Hereinafter, as the fine particle production apparatus and fine particle production method of the present embodiment, a toner production apparatus and a toner production method using a toner composition liquid as the fine particle raw material containing liquid will be described as an example.
The toner composition liquid is a liquid containing a toner material to be described later, and is, for example, a dissolved or dispersed liquid in which at least a resin and a colorant are dissolved or dispersed in a volatilizable solvent.

FIG. 1 is a schematic diagram showing the overall configuration of a toner production apparatus as a fine particle production apparatus of the present embodiment.
The toner manufacturing apparatus 1 includes a liquid supply unit, a droplet discharge unit, a transport solidifying unit, and a solidified particle collecting unit, and manufactures toner as fine particles.

[Liquid supply means, liquid supply step]
The liquid supply means includes a toner composition liquid tank 13 containing the toner composition liquid 14, a toner composition liquid feeding means for supplying the toner composition liquid 14 from the toner composition liquid tank 13, and a solid content adjustment for adjusting the solid content concentration of the liquid. And a degassing means for degassing the dissolved gas in the toner composition liquid 14 and a temporary storage container 5 as a temporary storage means for temporarily storing the degassed liquid. Supply toner composition liquid.

The toner composition liquid tank 13 stores the toner composition liquid 14 prepared in a separate process, and supplies the toner composition liquid 14 to the solid content adjusting means through the toner composition liquid flow path 7. In the toner composition liquid tank 13, it is preferable to stir the toner composition liquid 14 in order to prevent sedimentation of solid components.
As the toner composition liquid feeding means, a general liquid feeding pump such as a gear pump or a rotary pump can be used, and the liquid feeding amount is controlled so that the storage amount of the temporary storage container 5 is constant.

  The deaeration means is used to remove dissolved gas in the toner composition liquid 14 for ejection stability. The deaeration means is not particularly limited, and examples thereof include an apparatus to which a method of removing the gas dissolved in the liquid by depressurizing the inside of the container and an apparatus to which a method of degassing by ultrasonic waves is applied.

In this embodiment, a deaeration device 3 composed of a hollow fiber membrane (manufactured by DIC, deaeration module SEPARERL PF03DG) and a deaeration means composed of a pump 4 are used. By passing the toner composition liquid 14 through a bundle of hollow fibers having gas permeability of the deaerator 3 and reducing the pressure inside the container of the bundle of hollow fibers by the pump 4, only the dissolved gas in the toner composition liquid 14 is obtained. Can be removed.
The deaeration means can be installed in a circulation path for circulating the toner composition liquid 14 in a closed system. By installing the deaerator 3 in the circulation path and allowing the toner composition liquid 14 to pass through a plurality of times, the remaining amount of dissolved gas can be greatly reduced.

In order to stabilize the ejection, it is desirable to appropriately control the pressure of the toner composition liquid 14 supplied to the droplet ejection means 11.
It is desirable that the pressure P1 applied to the droplet discharge unit 11 and the pressure P2 of the solidified particle collecting unit satisfy the relationship P1≈P2. When the pressure is in the relationship of P1> P2, the toner composition liquid 14 may ooze out from the discharge hole of the droplet discharge means 11, and when the pressure is in the relationship of P1 <P2, gas is supplied to the droplet discharge means 11. Entering and discharging may stop.

  Further, a waste liquid tank 30 for storing the waste liquid discharged from the droplet discharge means 11 and an opening / closing valve for opening and closing a path to the waste liquid tank 30 are provided.

[Droplet ejection means, droplet ejection process]
The droplet discharge means 11 is not particularly limited as long as the toner composition liquid 14 can be made into droplets and the particle size distribution of the discharged droplets is narrow, and a known droplet discharge means can be used.
Examples of the droplet discharge means include a one-fluid nozzle, a two-fluid nozzle, a membrane vibration type discharge means (for example, described in JP-A-2008-292976), a Rayleigh split type discharge means (for example, described in Japanese Patent No. 4647506), a liquid Examples thereof include vibration type discharge means (for example, described in JP 2010-102195 A) and liquid column resonance discharge means (for example, described in JP 2011-212668 A). preferable.

The liquid column resonance discharge means includes a liquid column resonance liquid chamber in which discharge holes are formed, and a vibration generating unit that applies vibration to the liquid containing the fine particle raw material in the liquid column resonance liquid chamber. A vibration is imparted to the liquid containing the fine particle raw material in the liquid column resonance liquid chamber to form a pressure standing wave by liquid column resonance, and the fine particle is formed from the discharge hole formed in a region that becomes an antinode of the pressure standing wave. It is the structure which discharges a raw material containing liquid.
It is preferable that a plurality of the discharge holes are formed in the liquid column resonance liquid chamber.

A liquid column resonance ejection unit (hereinafter referred to as “liquid column resonance type droplet ejection unit”) will be described with reference to FIGS.
As shown in FIG. 2, the liquid column resonance type droplet discharge means 11 includes a liquid common supply path 17 and a liquid column resonance liquid chamber (flow path) 18. The liquid column resonance liquid chamber 18 communicates with a liquid common supply path 17 provided on one of the wall surfaces at both ends in the longitudinal direction. Further, the liquid column resonance liquid chamber 18 is provided on a wall surface facing the discharge hole 19 and a discharge hole 19 for discharging the droplet 21 to one wall surface of the wall surfaces connected to both ends. Vibration generating means 20 for generating high-frequency vibrations to form standing waves. The vibration generating means 20 is connected to a high frequency power source.

  In the liquid column resonance liquid chamber 18 filled with the toner composition liquid 14, a pressure distribution is formed by the liquid column resonance standing wave generated by the vibration generating means 20. Then, the droplet 21 is ejected from the ejection hole 19 arranged in a region where the amplitude of the liquid column resonance standing wave is large and the pressure fluctuation is large and which is an antinode of the standing wave.

  The region that becomes the antinode of the standing wave due to the liquid column resonance means a region other than the node of the standing wave. Preferably, it is a region where the pressure fluctuation of the standing wave has an amplitude large enough to discharge the liquid, and more preferably a position where the amplitude of the pressure standing wave becomes a maximum (a section as a velocity standing wave). ) To a minimum position in a range of ± 1/4 wavelength. If the region is an antinode of a standing wave, even if there are a plurality of discharge holes, substantially uniform droplets can be formed from each, and moreover, the droplets can be discharged efficiently. And clogging of the discharge holes is less likely to occur.

  When the amount of the toner composition liquid 14 in the liquid column resonance liquid chamber 18 decreases due to the discharge of the liquid droplets 21, a suction force due to the action of the liquid column resonance standing wave in the liquid column resonance liquid chamber 18 acts, and the liquid common supply The flow rate of the toner composition liquid 14 supplied from the passage 17 increases, and the toner composition liquid 14 is replenished in the liquid column resonance liquid chamber 18. When the toner composition liquid 14 is replenished in the liquid column resonance liquid chamber 18, the flow rate of the toner composition liquid 14 passing through the liquid common supply path 17 is restored.

The liquid column resonance liquid chamber 18 in the liquid column resonance type droplet discharge means 11 is a frame formed of a material having such a high rigidity that does not affect the resonance frequency of the liquid at a driving frequency such as metal, ceramics, or silicon. Are joined to each other.
Further, as shown in FIG. 2, the length L between the wall surfaces at both ends in the longitudinal direction of the liquid column resonance liquid chamber 18 is determined based on the liquid column resonance principle as described later. Further, it is desirable that the width W of the liquid column resonance liquid chamber 18 is smaller than a half of the length L of the liquid column resonance liquid chamber 18 so as not to give an extra frequency to the liquid column resonance.

  A plurality of liquid column resonance liquid chambers 18 are preferably arranged in order to drastically improve productivity. For example, one liquid droplet ejection means provided with 100 to 2000 liquid column resonance liquid chambers 18 is provided. (Droplet forming unit) is more preferable because both operability and productivity can be achieved.

  A flow path for supplying the toner composition liquid is connected to the liquid column resonance liquid chamber 18 from the liquid common supply path 17, and the liquid common supply path 17 communicates with a plurality of liquid column resonance liquid chambers 18.

The vibration generating means 20 in the liquid column resonance type droplet discharging means 11 is not particularly limited as long as it can be driven at a predetermined frequency, but a form in which a piezoelectric body is bonded to the elastic plate 9 is desirable.
The elastic plate 9 constitutes a part of the wall of the liquid column resonance liquid chamber so that the piezoelectric body does not come into contact with the liquid.
Examples of the piezoelectric body include piezoelectric ceramics such as lead zirconate titanate (PZT). However, since the amount of displacement is generally small, the piezoelectric body is often used by being laminated. In addition, piezoelectric polymers such as polyvinylidene fluoride (PVDF), single crystals such as quartz, LiNbO ₃ , LiTaO ₃ , KNbO _{3, and the} like can be given.
It is desirable that the vibration generating means 20 is arranged so that it can be individually controlled for each liquid column resonance liquid chamber 18. In addition, the block-shaped vibrating member made of one material as described above is partly cut in accordance with the arrangement of the liquid column resonance liquid chamber 18 so that each liquid column resonance liquid chamber 18 can be individually controlled via the elastic plate 9. Configuration is desirable.

The diameter of the opening of the discharge hole 19 is desirably in the range of 1 μm to 40 μm.
If the diameter of the opening is smaller than 1 μm, the formed droplets become very small, and thus toner may not be obtained. Also, when solid fine particles such as pigment are contained as a constituent component of the toner, There is a risk that the clogging occurs and the productivity is lowered.
On the other hand, when the diameter of the opening is larger than 40 μm, the diameter of the droplet increases, and the toner composition is very dilute with an organic solvent in order to obtain a desired toner particle diameter (3 to 6 μm) by drying and solidifying it. It may be necessary to dilute into the liquid, and a large amount of drying energy is required to obtain a certain amount of toner.

  As can be seen from FIG. 2, by providing the discharge holes 19 in the width direction in the liquid column resonance liquid chamber 18, a large number of openings of the discharge holes 19 can be provided, and the production efficiency can be increased. Further, since the liquid column resonance frequency varies depending on the arrangement of the discharge holes 19, it is desirable to appropriately determine the liquid column resonance frequency after confirming the discharge of the droplet.

The cross-sectional shape of the discharge hole 19 is not limited to the tapered shape shown in FIG. 2, and can be selected as appropriate.
FIG. 3 shows a cross-sectional shape that the discharge hole 19 can take.
FIG. 3A shows a shape in which the opening diameter becomes narrower while having a round shape from the liquid contact surface of the discharge hole 19 toward the discharge port. When the thin film 41 vibrates, the liquid is near the outlet of the discharge hole 19. Is the most preferable shape for stabilizing the discharge.
FIG. 3B shows a shape in which the opening diameter becomes narrower from the liquid contact surface of the discharge hole 19 toward the discharge port, and the nozzle angle 24 can be appropriately changed. The pressure applied to the liquid can be adjusted in the vicinity of the outlet of the discharge hole 19 when the thin film 41 is vibrated by the nozzle angle 24, and the range is preferably 60 to 90 °. When the nozzle angle 24 is less than 60 °, it is difficult to apply pressure to the liquid, and it is difficult to process the thin film 41.
A case where the nozzle angle 24 is 90 ° is shown in FIG. When the nozzle angle 24 is larger than 90 °, no pressure is applied to the outlet of the discharge hole 19 and the droplet discharge becomes very unstable. The maximum nozzle angle 24 is 90 °.
Moreover, it can also be set as the shape changed in steps like FIG.3 (d).

Next, the mechanism of droplet formation by the liquid column resonance type droplet discharge means 11 will be described.
First, the principle of the liquid column resonance phenomenon that occurs in the liquid column resonance liquid chamber 18 in the liquid column resonance type droplet discharge means 11 of FIG. 2 will be described.
When the sound velocity of the toner composition liquid in the liquid column resonance liquid chamber 18 is c, and the driving frequency applied to the toner composition liquid as a medium from the vibration generating means 20 is f, the wavelength λ at which the liquid resonance occurs is It has the relationship of the following formula 1.

  λ = c / f (Formula 1)

  Further, in the liquid column resonance liquid chamber 18 of FIG. 2, the length from the end of the frame on the fixed end side to the end on the liquid common supply path 17 side is L, and further, the end of the frame on the liquid common supply path 17 side. The height h1 (= about 80 μm) is about twice as high as the communication port height h2 (= about 40 μm). Resonance is most efficiently formed when the length L matches an even multiple of a quarter of the wavelength λ. That is, it is expressed by the following formula 2.

L = (N / 4) λ (Expression 2)
(However, N is an even number.)

Furthermore, the above formula 2 is also established in the case of a double-sided open end where both ends are completely open.
Similarly, when one side is equivalent to an open end having a pressure relief portion and the other side is closed (fixed end), that is, one side fixed end or one side open end, the length L is the wavelength λ. Resonance is most efficiently formed when it matches an odd multiple of a quarter. That is, N in Expression 2 is expressed as an odd number.

  The most efficient driving frequency f is derived from the above formula 1 and the above formula 2 as the following formula 3.

  f = N × c / (4L) (Formula 3)

  However, in reality, since the liquid has a viscosity that attenuates the resonance, the vibration is not amplified infinitely, and has a Q value. As shown in equations 4 and 5, which will be described later, Resonance also occurs at frequencies near the highly efficient drive frequency f.

  FIG. 4 shows the shape of the standing wave of velocity and pressure fluctuation (resonance mode) when N = 1, 2, 3 and FIG. 5 shows the standing wave of velocity and pressure fluctuation when N = 4, 5. The shape (resonance mode) is shown. Originally, it is a dense wave (longitudinal wave), but it is generally expressed as shown in FIGS. The solid line is the velocity standing wave, and the dotted line is the pressure standing wave.

  For example, as can be seen from FIG. 4A showing the case of one fixed end with N = 1, in the case of velocity distribution, the amplitude of the velocity distribution is zero at the closed end, and the amplitude is maximum at the open end. Easy to understand. When the length between both ends in the longitudinal direction of the liquid column resonance liquid chamber is L, the wavelength at which the liquid resonates is λ, and the standing wave is most efficiently generated when the integer N is 1 to 5. . In addition, since the standing wave pattern varies depending on the open / closed state of both ends, they are also shown. As will be described later, the condition of the end is determined by the state of the opening of the discharge hole and the opening of the supply side.

  In acoustics, the open end is an end where the moving speed of the medium (liquid) in the longitudinal direction becomes maximum, and conversely, the pressure becomes minimum. Conversely, the closed end is defined as an end where the moving speed of the medium becomes zero. The closed end is considered as an acoustically hard wall and wave reflection occurs. When ideally completely closed or open, a resonant standing wave of the form shown in FIGS. 4 and 5 is generated by superposition of waves, but it is also determined by the number of discharge holes and the position of the discharge holes. The standing wave pattern fluctuates, and the resonance frequency appears at a position deviated from the position obtained from the above equation 3. However, stable ejection conditions can be created by appropriately adjusting the driving frequency. For example, the sound velocity c of the liquid is 1,200 m / s, the length L of the liquid column resonance liquid chamber is 1.85 mm, wall surfaces exist at both ends, and N = 2 resonance that is completely equivalent to the fixed ends on both sides. When the mode is used, the most efficient resonance frequency is derived as 324 kHz from the above equation (2). In another example, the sound velocity c of the liquid is 1,200 m / s, the length L of the liquid column resonance liquid chamber is 1.85 mm, and the same conditions as described above are used. When the equivalent N = 4 resonance mode is used, the most efficient resonance frequency is derived from the above equation (2) as 648 kHz, and higher-order resonance is utilized even in the liquid column resonance liquid chamber having the same configuration. can do.

The liquid column resonance liquid chamber in the liquid column resonance type droplet discharge means 11 shown in FIG. 2 can be described as an acoustically soft wall due to whether the both ends are equivalent to the closed end state or the influence of the opening of the discharge hole. Although it is preferable for the frequency to increase, it is not limited to this, but it may be an open end. The influence of the opening of the discharge hole here means that the acoustic impedance is reduced, and in particular, the compliance component is increased.
Therefore, the configuration in which the wall surfaces are formed at both ends in the longitudinal direction of the liquid column resonance liquid chamber as shown in FIG. 4B and FIG. 5A is regarded as the resonance mode at both fixed ends and the discharge hole side as an opening. This is a preferred configuration because all resonance modes at one open end can be used.

  In addition, the numerical aperture of the discharge holes, the opening arrangement position, and the cross-sectional shape of the discharge holes are factors that determine the drive frequency, and the drive frequency can be appropriately determined accordingly. For example, when the number of ejection holes is increased, the restriction at the tip of the liquid column resonance liquid chamber, which has been the fixed end, gradually loosens, a resonance standing wave that is almost close to the open end is generated, and the drive frequency increases. In addition, the opening position of the discharge hole that is closest to the liquid supply path is the starting point, and it becomes a loose constraint condition. The cross-sectional shape of the discharge hole is round, or the volume of the discharge hole varies depending on the thickness of the frame. The upper standing wave has a short wavelength and is higher than the driving frequency. When a voltage is applied to the vibration generating means at the drive frequency determined in this way, the vibration generating means is deformed, and a resonant standing wave is generated most efficiently at the drive frequency. Further, the liquid column resonance standing wave is generated even at a frequency in the vicinity of the drive frequency at which the resonance standing wave is generated most efficiently. That is, when the length between both ends in the longitudinal direction of the liquid column resonance liquid chamber is L and the distance to the discharge hole closest to the end on the liquid supply side is Le, both the lengths of L and Le are used. It is possible to oscillate the vibration generating means by using a drive waveform whose main component is the drive frequency f in the range determined by the following formulas 4 and 5, and induce liquid column resonance to eject liquid droplets from the ejection holes. It is.

N × c / (4L) ≦ f ≦ N × c / (4Le) (Formula 4)
N × c / (4L) ≦ f ≦ (N + 1) × c / (4Le) (Formula 5)

  The ratio Le / L between the length L between both ends in the longitudinal direction of the liquid column resonance liquid chamber and the distance Le to the discharge hole closest to the end on the liquid supply side satisfies Le / L> 0.6. It is preferable to satisfy.

The liquid column resonance pressure standing wave is formed in the liquid column resonance liquid chamber 18 of FIG. 2 using the principle of the liquid column resonance phenomenon described above, and the discharge holes 19 arranged in a part of the liquid column resonance liquid chamber 18. In this case, droplet discharge occurs continuously.
Note that it is preferable to dispose the discharge hole 19 at a position where the pressure of the standing wave fluctuates the most, since the discharge efficiency is increased and the driving can be performed with a low voltage.

Further, one discharge hole 19 may be provided in one liquid column resonance liquid chamber 18, but it is preferable to arrange a plurality of discharge holes 19 from the viewpoint of productivity. Specifically, the number of discharge holes 19 is between 2 and 100. preferable.
When the number of ejection holes 19 exceeds 100, it is necessary to set a high voltage to the vibration generating means 20 when desired droplets are formed, and the behavior of the piezoelectric body as the vibration generating means 20 becomes unstable. . When the plurality of discharge holes 19 are opened, the pitch between the discharge holes is preferably 20 μm or more and not more than the length of the liquid column resonance liquid chamber 18. When the pitch between the discharge holes is smaller than 20 μm, there is a high probability that the droplets discharged from the adjacent discharge holes 19 collide with each other to form large droplets, leading to deterioration in the toner particle size distribution.

Next, the state of the liquid column resonance phenomenon occurring in the liquid column resonance liquid chamber 18 will be described with reference to FIG.
In FIG. 6, the solid line written in the liquid column resonance liquid chamber 18 is at any measurement position from the fixed end side in the liquid column resonance liquid chamber 18 to the end on the liquid common supply path 17 side. The velocity distribution plotting the velocity is shown, and the direction from the common liquid supply path 17 side to the liquid column resonance liquid chamber 18 is “+”, and the opposite direction is “−”. The dotted line in the liquid column resonance liquid chamber 18 plots the pressure value at any measurement position from the fixed end side in the liquid column resonance liquid chamber 18 to the end portion on the liquid common supply path 17 side. The positive pressure is “+” and the negative pressure is “−” with respect to the atmospheric pressure. Moreover, if it is a positive pressure, a pressure will be applied to the downward direction in FIG. 6, and if it is a negative pressure, a pressure will be applied to the upward direction in FIG.

  Further, in FIG. 6, the liquid common supply path 17 side is opened as described above, but the height of the opening where the liquid common supply path 17 communicates with the liquid column resonance liquid chamber 18 (the height h <b> 2 shown in FIG. 2). ) Is approximately twice or more the height of the frame serving as the fixed end (height h1 shown in FIG. 2), so that the approximate condition that the liquid column resonance liquid chamber 18 is substantially fixed on both sides is obtained. The respective changes over time in the original velocity distribution and pressure distribution are shown.

FIG. 6 shows a pressure waveform and a velocity waveform in the liquid column resonance liquid chamber 18 when droplets are discharged.
FIG. 6A shows a state where the meniscus pressure increases again after the liquid is drawn immediately after the droplet is discharged. As shown in FIG. 6A, the pressure in the flow path provided with the discharge hole 19 in the liquid column resonance liquid chamber 18 is maximum. Thereafter, as shown in FIG. 6B, the positive pressure in the vicinity of the ejection hole 19 decreases, and the liquid droplet 21 is ejected in a negative pressure direction.

  And as shown in FIG.6 (c), the pressure of the discharge hole 19 vicinity becomes minimum. From this time, the filling of the toner composition liquid 14 into the liquid column resonance liquid chamber 18 starts. Thereafter, as shown in FIG. 6D, the negative pressure in the vicinity of the discharge hole 19 becomes smaller and shifts in the positive pressure direction. At this time, the filling of the toner composition liquid 14 is completed. Then, as shown in FIG. 6A again, the positive pressure in the droplet discharge region of the liquid column resonance liquid chamber 18 becomes maximum, and the droplet 21 is discharged from the discharge hole 19. In this way, a standing wave due to liquid column resonance is generated in the liquid column resonance liquid chamber by high-frequency driving of the vibration generating means, and corresponds to an antinode of standing wave due to liquid column resonance where the pressure changes most. Since the discharge holes 19 are arranged in the droplet discharge region to be discharged, the droplets 21 are continuously discharged from the discharge holes 19 in accordance with the antinode period.

Next, a configuration in which droplets are ejected by the liquid column resonance phenomenon will be described.
The length L between the longitudinal ends of the liquid column resonance liquid chamber 18 is 1.85 mm and the resonance mode is N = 2, and the first to fourth discharge holes are antinodes of the N = 2 mode pressure standing wave. The diameter of the opening of the discharge hole is 10 μm, and the discharge performed with a sine wave with a driving frequency of 330 kHz was observed by laser shadowography, as a result, the diameter was very uniform. The discharge of droplets with almost the same speed was realized.
In the first to fourth nozzles, the discharge speed from each nozzle was uniform and the maximum discharge speed when the drive frequency was around 330 kHz.
From this result, it was found that uniform ejection was realized at the antinode of the liquid column resonance standing wave at 330 kHz which is the second mode of the liquid column resonance frequency.

[Transport solidification means, transport solidification process]
The above-described droplet discharge means 11 causes the toner composition liquid 14 to be discharged into the conveying airflow, and the discharged droplets 21 of the toner composition liquid 14 are dried and solidified by the conveying solidification means and the conveying solidification step. Here, solidification means that the liquid droplets are dried, and the liquid droplets described later are not bonded or joined together.

As shown in FIG. 1, the transport solidification means includes a transport flow path 12 that is a flow path for the droplets 21 and the transport airflow 70, a transport airflow generation means that generates the transport airflow 70, and a wall surface of the transport flowpath 12. And an auxiliary airflow generating means for generating an auxiliary airflow 71 that flows from the downstream side to the upstream side in the transport direction of the droplets 21. The conveyance flow path 12 has an expanded portion 73 whose cross-sectional area is expanded toward the downstream side, and the auxiliary air flow 71 flows along the wall surface of the expanded portion 73.
In the transport and solidification step, the auxiliary airflow 71 is formed along the wall surface of the extension 73.

The transport channel 12 has a droplet discharge space in which the droplet discharge means 11 is arranged on the upstream wall surface, and is substantially orthogonal to the discharge direction with respect to the droplet 21 discharged from the droplet discharge means 11. The air flow 70 is guided so that the droplets 21 are conveyed in the direction in which the liquid drops 21 are conveyed.
The wall surface on which the droplet discharge means 11 is arranged is, for example, the inner surface (inner diameter) surface when the transport channel 12 is cylindrical, and the inner surfaces when the transport channel is prismatic. One of them.
The discharge hole 19 of the droplet discharge means 11 is exposed to the transport channel 12.

  In the fine particle manufacturing apparatus and the fine particle manufacturing method of the present embodiment, the air flow 70 is introduced to prevent the discharged droplets 21 from adhering, and the droplets 21 adhere to the wall surface of the transport flow path 12. In order to prevent this, the conveyance flow path 12 having the expansion part 73 is provided, and the auxiliary air flow 71 is introduced from the downstream side of the expansion part 73.

(Preventing droplet adhesion)
The fine particle manufacturing apparatus according to the present embodiment is a means for maintaining a sufficient distance between the droplets 21 discharged from the droplet discharge means 11 and preventing coalescence in order to obtain solidified particles having a uniform particle size distribution. As a carrier airflow generation means.
Here, coalescence refers to a phenomenon in which the droplets 21 ejected from the droplet ejection means 11 adhere to each other before drying and merge into one droplet.
The droplet 21 ejected from the droplet ejection means 11 has a constant initial velocity immediately after ejection, but gradually decelerates due to the fluid resistance of the surrounding gas and coalesces with the droplet 21 ejected later. May end up. Further, when the droplets discharged from the adjacent discharge holes 19 of the droplet discharge means 11 come into contact before solidifying, the droplets 21 may be similarly bonded.

As a method for preventing the adhesion of the droplets, there are a method of introducing the carrier airflow 70 in the vicinity of the droplet discharge means 11 by the carrier airflow generating means, a method of charging the droplets 21 with the same polarity, and controlling the electric field. Can be mentioned.
In the present embodiment, a method is adopted in which the carrier airflow 70 is introduced into the carrier channel 12 by the carrier airflow generating means.

  The carrier airflow 70 can be, for example, an airflow substantially orthogonal to the direction in which the droplets 21 are discharged from the droplet discharge means 11. The droplets 21 discharged from the droplet discharge means 11 are transported while the flight direction is bent by the transport airflow 70. Further, when the flight direction changes, the droplet 21 diffuses, and the droplet interval can be widened. With such a configuration, the coalescence of the droplets 21 can be suppressed with a simple structure, and particles with a sharp particle size distribution can be obtained.

  The conveying airflow generating means is not particularly limited as long as it is a means capable of generating an airflow, and a known air blowing means or suction means can be used. Examples of the method for generating the carrier airflow include a method in which the carrier airflow introduction unit 64 is provided with a blowing means and pressurizing, and a method in which the carrier airflow discharge unit 65 is provided with a suction means for suction.

(Prevention of droplets from adhering to the wall of the transport channel)
Since the droplets 21 discharged from the droplet discharge means 11 are conveyed while being bent and diffused by the conveying airflow 70 in the conveying channel 12, the droplets 21 may adhere to the wall surface on the downstream side of the conveying channel 12. There is. In particular, in the case of a configuration having a maintenance structure such as cleaning, the distance to which the droplets 21 are transported becomes long and it is easy to hit the wall.
Since the transport airflow 70 is turbulent in the transport flow path 12, the airflow velocity is substantially uniform, and the droplets 21 are carried downstream along the transport airflow 70. At this time, since the droplets 21 are diffused by the transport air flow 70, the droplets 21 adhere to the wall surface of the transport channel 12 if the transport distance is long. If the adhered droplet 21 is not completely dry, it adheres to the wall surface, and maintenance such as cleaning becomes necessary.
In order to ensure the maintainability of the fine particle manufacturing apparatus and realize high productivity, it is necessary to provide means for preventing the droplets 21 from adhering to the wall surface of the transport flow path 12.

  From the viewpoint of hydrodynamics, the droplet 21 is attached to the wall surface of the transport channel 12 by controlling the flow velocity of the transport air flow 70 in the transport channel 12 to be relatively larger on the center side than on the wall side. Can be prevented. This is because the pressure in the central region where the flow velocity of the carrier airflow 70 is relatively large is reduced, and the flow in the peripheral region (wall side region) is drawn, so that the droplet 21 riding on the carrier airflow 70 diffuses in the wall side direction. This is because it can be suppressed.

  The fine particle manufacturing apparatus of the present embodiment has a configuration in which the flow velocity of the conveyance airflow 70 in the conveyance flow path 12 is relatively larger at the center side than at the wall side at least in the expanded portion 73, and the conveyance solidification step. The flow velocity of the conveyance airflow 70 in the conveyance flow path 12 is controlled so as to be relatively larger at the center side than at the wall side at least in the extended portion 73.

Note that the flow velocity of the auxiliary airflow 71 is preferably smaller than the flow velocity of the carrier airflow 70.
When the flow velocity of the auxiliary air flow 71 is larger than the flow velocity of the carrier air flow 70, a sufficient adhesion preventing effect may not be obtained.

The relationship between the expansion part 73 and the auxiliary airflow 71 will be described.
As a method of increasing the flow velocity of the carrier airflow 70 on the center side rather than the wall side of the carrier channel 12, a method of increasing (rapidly expanding) the expansion ratio of the expansion part 73 of the carrier channel 12 can be mentioned. However, there is a possibility that a swirling flow called a back step flow is generated in a portion where the conveying flow path 12 is suddenly expanded, and the suspended droplet 21 rides on this flow and adheres to the wall surface. On the other hand, by providing an auxiliary airflow introduction portion 72 at the downstream end of the expansion portion 73 of the transport flow path 12, the auxiliary airflow 71 flowing from the downstream side to the upstream side is sent from the auxiliary airflow introduction portion 72 to the wall surface of the expansion portion 73. Thus, it is possible to prevent the suspended droplets from adhering to the wall of the extension 73.

  The auxiliary airflow generation means is not particularly limited as long as it can generate airflow, and a known air blowing means can be used. Examples of the method of generating the auxiliary airflow include a method of generating an airflow by providing a blowing means in the auxiliary airflow introduction unit 72 and a method of generating an airflow by supplying a gas pressurized by a compressor or the like.

About the distribution of the flow velocity of the conveyance airflow 70 in the conveyance flow path 12, it can measure by a well-known detection means.
For example, by using a fluid simulation in which the conveyance channel is modeled by measurement using a visualization method using the PIV method (particle image velocity measurement method), the flow velocity of the conveyance air flow 70 in the conveyance channel 12 is at least the expansion unit 73. It can be confirmed that the center side is relatively larger than the wall side.

[First embodiment]
FIG. 7 is a cross-sectional view showing a first embodiment of the conveying and solidifying means.
The conveyance flow path 12 has an expansion portion 73, and an auxiliary airflow introduction portion 72 is provided at the downstream end of the expansion portion 73, and the auxiliary airflow 71 is introduced from the auxiliary airflow introduction portion 72.
Since the extended portion 73 has a shape that expands rapidly in a stepped manner, a backstep flow is generated as described above, and the suspended droplet 21 is carried toward the wall surface. Can be suppressed.

[Second Embodiment]
FIG. 8 is a cross-sectional view showing a second embodiment of the conveying and solidifying means.
The conveyance flow path 12 has an expanded portion 73 having a reverse taper-shaped cross section, and an auxiliary air flow introduction portion 72 is provided at the downstream end of the expansion portion 73, and the auxiliary air flow 71 is introduced from the auxiliary air flow introduction portion 72. The As in the first embodiment, the auxiliary airflow 71 can suppress the droplet 21 from adhering to the wall surface.
Moreover, the cross-sectional shape of the expansion part 73 is the reverse taper shape whose cross-sectional area becomes wider toward the downstream, so that the effect of preventing the droplet 21 from adhering to the wall surface is enhanced.

[Third embodiment]
FIG. 9 is a cross-sectional view showing a third embodiment of the conveying and solidifying means.
The conveyance flow path 12 has an expanded portion 73 having a reverse taper-shaped cross section from a portion expanded in a stepped shape, and an auxiliary air flow introducing portion 72 is provided at the downstream end of the expanded portion 73, and the auxiliary air flow introducing portion An auxiliary airflow 71 is introduced from 72. As in the first embodiment, the auxiliary airflow 71 can suppress the droplet 21 from adhering to the wall surface.
As in the second embodiment, the effect of preventing the droplet 21 from adhering to the wall surface is further enhanced by including an inversely tapered shape in which the cross-sectional shape of the expanded portion 73 becomes wider in the downstream direction. .

[Fourth embodiment]
FIG. 10 is a cross-sectional view showing a fourth embodiment of the conveying and solidifying means.
The conveyance flow path 12 has an extended portion 73 having a reverse tapered cross section on the opposite surface of the wall surface on which the droplet discharge means 11 is provided, and an auxiliary air flow introducing portion 72 is provided at the downstream end of the extended portion 73. The auxiliary airflow 71 is provided from the auxiliary airflow introduction unit 72. As in the first embodiment, the auxiliary airflow 71 can suppress the droplet 21 from adhering to the wall surface.
A maintenance mechanism such as a cleaning means can be installed on the wall surface provided with the droplet discharge means 11 in which the reverse taper shape and the auxiliary airflow introduction portion 72 are not formed.

In the transport solidifying means described above, the droplets 21 are dried by gradually evaporating the volatile solvent contained in the toner composition liquid 14 from the liquid state immediately after being discharged from the droplet discharge means 11 by the transport air flow 70. Proceeds to a solid.
The solidification method can be appropriately selected according to the properties of the toner composition liquid 14. For example, if the toner composition liquid 14 is obtained by dissolving or dispersing solid raw materials in a volatile solvent, a method of volatilizing (drying) the solvent of the droplets 21 in the conveying airflow 70 can be used. Specifically, the drying state can be adjusted by appropriately selecting the temperature, vapor pressure, gas type, and the like of the carrier airflow 70. Further, the particles may be collected in a state where the volatile components are not completely volatilized, and additional drying may be performed as a separate step after the collection.

[Solidified particulate collection means]
The droplets 21 that have been changed to solid in the above-described transport solidifying means are collected as toner powder by the solidified fine particle collecting means.
As shown in FIG. 1, the solidified fine particle collecting means includes a chamber 61, a toner collecting unit (solidified particle collecting unit) 62, and a toner storage unit (solidified particle storage unit) 63.
The toner collecting method can be selected from known powder collecting means. For example, the toner can be collected by cyclone collection, a back filter, or the like.
The collected toner powder is stored in the toner storage unit 63. The toner stored in the toner storage unit 63 is further dried in another process as necessary.

(Secondary drying)
When the amount of residual solvent contained in the obtained toner particles is large, secondary drying is performed by secondary drying means as necessary to reduce this. As the secondary drying means, general known drying means such as fluidized bed drying or vacuum drying can be used. If the organic solvent remains in the toner, not only the toner characteristics such as heat-resistant storage stability, fixing properties, and charging characteristics will change over time. Since the organic solvent volatilizes during fixing by heating, the possibility of adverse effects on the user and peripheral equipment is increased. Therefore, sufficient drying is performed.

〔toner〕
The toner according to the exemplary embodiment is manufactured by the above-described microparticle manufacturing apparatus and microparticle manufacturing method, and contains at least a resin, a colorant, and a wax, and optionally includes a charge adjusting agent, an additive, and other components.

The “toner composition liquid” used in the production of the toner of the present embodiment will be described.
The toner composition liquid may be in a liquid state in which the toner component is dissolved or dispersed in a solvent, or may be free from a solvent as long as it is liquid under the conditions for ejection, and a part or all of the toner component is in a molten state. In a liquid state.
As the toner material, if the toner composition liquid described above can be adjusted, the same material as the conventional electrophotographic toner can be used. As described above, it is possible to make fine droplets from the droplet discharge means, and collect the solidified particles by the solidified particle collecting means to produce the target toner particles.

(resin)
Examples of the resin include at least a binder resin.
The binder resin is not particularly limited, and a commonly used resin can be appropriately selected and used. For example, a styrene monomer, an acrylic monomer, a methacrylic monomer, etc. Vinyl polymers, copolymers of these monomers or two or more types, polyester polymers, polyol resins, phenol resins, silicone resins, polyurethane resins, polyamide resins, furan resins, epoxy resins, xylene resins, terpene resins , Coumarone indene resin, polycarbonate resin, petroleum resin, and the like.

  As the properties of the binder resin, it is desirable that the binder resin be dissolved in a solvent.

(Molecular weight distribution of binder resin)
The molecular weight distribution of the binder resin by GPC (gel permeation chromatography) preferably has at least one peak in the region of molecular weight of 3,000 to 50,000 from the viewpoint of toner fixing property and offset resistance. As the THF-soluble component, a binder resin in which a component having a molecular weight of 100,000 or less is 60 to 100% is preferable, and a binder resin having at least one peak in a region having a molecular weight of 5,000 to 20,000 is more preferable. preferable.

(Binder resin acid value)
What has 60 mass% or more of resin which has an acid value of 0.1-50 mgKOH / g of binder resin is preferable. In the present invention, the acid value of the binder resin component of the toner composition is measured according to JIS K-0070.

  As the magnetic material that can be used in the toner of the present embodiment, known materials that are conventionally used in electrophotographic toners can be used. For example, (1) iron oxide containing magnetic iron oxide such as magnetite, maghemite and ferrite, and other metal oxides, (2) metals such as iron, cobalt, nickel, or these metals and aluminum, cobalt, copper Alloys with metals such as lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium. (3) and mixtures thereof are used. The magnetic material can also be used as a colorant. As the usage-amount of the said magnetic body, 10-200 mass parts of magnetic bodies are preferable with respect to 100 mass parts of binder resin, and 20-150 mass parts is more preferable. The number average particle diameter of these magnetic materials is preferably 0.1 to 2 μm, and more preferably 0.1 to 0.5 μm. The number average diameter can be obtained by measuring a photograph taken with a transmission electron microscope with a digitizer or the like.

(Coloring agent)
The colorant is not particularly limited, and a commonly used resin can be appropriately selected and used.

  The content of the colorant is preferably 1 to 15% by mass and more preferably 3 to 10% by mass with respect to the toner.

  The colorant used in the toner of this embodiment can also be used as a master batch combined with a resin. The master batch is for dispersing the pigment in advance, and may not be used if sufficient dispersion of the pigment is obtained. In general, a master batch is obtained by dispersing a pigment in hardness in a resin by applying high shear to the pigment and the resin. A conventionally well-known thing can be used as binder resin knead | mixed with manufacture of a masterbatch or a masterbatch. These may be used individually by 1 type, and 2 or more types may be mixed and used for them.

  As the usage-amount of the said masterbatch, 0.1-20 mass parts is preferable with respect to 100 mass parts of binder resin.

  A dispersant may be used to increase the dispersibility of the pigment during the production of the masterbatch. From the viewpoint of pigment dispersibility, it is preferable that the compatibility with the binder resin is high, and conventionally known ones can be used. Specific commercial products include “Ajisper PB821”, “Azisper PB822” Techno), “Disperbyk-2001” (by Big Chemie), “EFKA-4010” (by EFKA), and the like.

  The addition amount of the dispersant is preferably 1 to 200 parts by mass, more preferably 5 to 80 parts by mass with respect to 100 parts by mass of the colorant. If it is less than 1 part by mass, the dispersibility may be lowered, and if it exceeds 200 parts by mass, the chargeability may be lowered.

〔wax〕
The toner composition liquid used in the production of the toner of the present embodiment contains a wax together with a binder resin and a colorant.
The wax is not particularly limited and can be appropriately selected from commonly used ones such as low molecular weight polyethylene, low molecular weight polypropylene, polyolefin wax, microcrystalline wax, paraffin wax, and sazol wax. Oxides of aliphatic hydrocarbon waxes such as aliphatic hydrocarbon waxes, polyethylene oxide waxes or block copolymers thereof, plant waxes such as candelilla wax, carnauba wax, wood wax, jojoba wax, beeswax, lanolin Waxes mainly composed of fatty acid esters such as animal waxes such as whale wax, mineral waxes such as ozokerite, ceresin, and petrolatum, and montanic acid ester waxes and castor waxes. Deoxidized carnauba wax and other fatty acid esters that have been partially or wholly deoxidized are included.

  The melting point of the wax is preferably 70 to 140 ° C., and more preferably 70 to 120 ° C., in order to balance the fixability and the offset resistance. If it is less than 70 degreeC, blocking resistance may fall, and if it exceeds 140 degreeC, an offset-proof effect may become difficult to express.

  The total content of the wax is preferably 0.2 to 20 parts by mass and more preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the binder resin.

  In the present invention, the temperature of the peak top of the endothermic peak of the wax measured by DSC (Differential Scanning Calorimetry) is defined as the melting point of the wax.

  The wax or toner DSC measuring device is preferably measured with a high-precision internal heat input compensation type differential scanning calorimeter. As a measuring method, it carries out according to ASTM D3418-82. The DSC curve used in the present invention is one that is measured when the temperature is raised at a temperature rate of 10 ° C./min after raising and lowering the temperature once and taking a previous history.

〔Additive〕
In the toner of this embodiment, as other additives, protection of the electrostatic latent image carrier / carrier, improvement of cleaning properties, adjustment of thermal characteristics / electrical characteristics / physical characteristics, resistance adjustment, softening point adjustment, fixing rate For the purpose of improvement, various metal soaps, fluorosurfactants, dioctyl phthalate, tin oxide, zinc oxide, carbon black, antimony oxide, etc. as conductivity imparting agents, and inorganic such as titanium oxide, aluminum oxide, alumina A fine powder or the like can be added as necessary. These inorganic fine powders may be hydrophobized as necessary. In addition, lubricants such as polytetrafluoroethylene, zinc stearate, polyvinylidene fluoride, abrasives such as cesium oxide, silicon carbide, strontium titanate, anti-caking agents, white particles and black particles having opposite polarity to the toner particles, Can also be used in small amounts as a developability improver.

  These additives have a silicone varnish, various modified silicone varnishes, silicone oil, various modified silicone oils, silane coupling agents, silane coupling agents having functional groups, and other organosilicons for the purpose of charge control and the like. It is also preferable to treat with a treating agent such as a compound or various treating agents.

  As the additive, inorganic fine particles can be preferably used. As said inorganic fine particle, well-known things, such as a silica, an alumina, a titanium oxide, can be used, for example.

  In addition, polymer fine particles such as polystyrene obtained by soap-free emulsion polymerization, suspension polymerization and dispersion polymerization, methacrylic acid ester and acrylic acid ester copolymer, polycondensation system such as silicone, benzoguanamine and nylon, thermosetting resin And polymer particles.

  Such an external additive can be made hydrophobic by the surface treatment agent and prevent deterioration of the external additive itself even under high humidity. Examples of the surface treatment agent include a silane coupling agent, a silylating agent, a silane coupling agent having a fluorinated alkyl group, an organic titanate coupling agent, an aluminum coupling agent, silicone oil, a modified silicone oil, Etc. are preferable.

The primary particle diameter of the external additive is preferably 5 nm to 2 μm, and more preferably 5 nm to 500 nm. Moreover, as a specific surface area by BET method, it is preferable that it is 20-500 m < ² > / g. The use ratio of the inorganic fine particles is preferably 0.01 to 5% by mass of the toner, and more preferably 0.01 to 2.0% by mass.

  Examples of the cleaning property improver for removing the developer after transfer remaining on the electrostatic latent image carrier or the primary transfer medium include fatty acid metal salts such as zinc stearate, calcium stearate, stearic acid, and polymethyl methacrylate. There may be mentioned polymer fine particles produced by soap-free emulsion polymerization such as fine particles and polystyrene fine particles. The polymer fine particles preferably have a relatively narrow particle size distribution and a volume average particle size of 0.01 to 1 μm.

Examples of the present invention will be described below.
First, a method for producing the toner composition liquid (dissolution or dispersion) used in this example will be described.
-Preparation of colorant dispersion-
First, a carbon black dispersion as a colorant was prepared.
17 parts by mass of carbon black (Rega L400; manufactured by Cabot) and 3 parts by mass of a pigment dispersant were primarily dispersed in 80 parts by mass of ethyl acetate using a mixer having stirring blades. As the pigment dispersant, Ajisper PB821 (manufactured by Ajinomoto Fine Techno Co., Ltd.) was used. The obtained primary dispersion is finely dispersed by a strong shearing force using a bead mill (LMZ type manufactured by Ashizawa Finetech Co., Ltd., zirconia bead diameter 0.3 mm), and the secondary dispersion in which aggregates of 5 μm or more are completely removed. A liquid was prepared.

-Preparation of wax dispersion-
Next, a wax dispersion was prepared.
18 parts by mass of carnauba wax and 2 parts by mass of a wax dispersant were primarily dispersed in 80 parts by mass of ethyl acetate using a mixer having stirring blades. The primary dispersion was heated to 80 ° C. with stirring to dissolve the carnauba wax, and then the liquid temperature was lowered to room temperature to precipitate wax particles so that the maximum diameter was 3 μm or less. As the wax dispersant, a polyethylene wax grafted with a styrene-butyl acrylate copolymer was used. The obtained dispersion was further finely dispersed by a strong shearing force using a bead mill (LMZ type manufactured by Ashizawa Finetech Co., Ltd., zirconia bead diameter 0.3 mm), and the maximum diameter was adjusted to 1 μm or less.

-Preparation of dissolution or dispersion-
Next, a toner composition liquid having the following composition to which a resin as a binder resin, the colorant dispersion, and the wax dispersion were added was prepared.
100 parts by mass of a polyester resin as a binder resin, 30 parts by mass of the colorant dispersion, 30 parts by mass of the wax dispersion, 400 parts by mass of ethyl acetate, and stirring for 10 minutes using a mixer having stirring blades, Evenly dispersed. Pigments and wax particles did not aggregate due to shock due to solvent dilution.

[Example 1 (first embodiment)]
As the droplet discharge means 11, a liquid column resonance type droplet discharge means shown in FIG. 2 was used.
Here, the length L between both ends of the liquid column resonance liquid chamber 18 in the longitudinal direction is 1.85 mm and N = 2, and the first to fourth discharge holes 19 have N = 2 mode pressure constant. The thing which has arranged the discharge hole in the position of the antinode of standing waves was used. The discharge hole 19 has an opening diameter of 10.0 μm, and the cross-sectional shape is a round shape as shown in FIG.
Further, a function generator WF 1973 manufactured by NF was used as a drive signal generation source, and connected to the vibration generating means 20 with a polyethylene-coated lead wire. The driving frequency at this time was 330 kHz in accordance with the liquid resonance frequency. The input signal was applied voltage sine wave peak value 10.0V.
As a result of measuring the droplet diameter and the discharge speed of the droplet when the droplet was discharged under the above conditions by the shadowography method, the average droplet diameter was 12 μm, and the average initial velocity of the discharged droplet was 14 m / s. Met.

  In the present embodiment, the droplet discharge means 11 includes two discharge holes 19 in which 192 liquid chambers (channels) having the first to fourth discharge holes 19 are arranged in the longitudinal direction. Two droplet discharge means (discharge heads) having a total of 1536 were used.

As the transport solidifying means, the transport solidifying means having the configuration shown in FIG. 7 was used.
The transport solidification means includes a transport flow path 12, a transport airflow generation means for generating a transport airflow 70, and an auxiliary airflow generation means for generating an auxiliary airflow 71, and is connected to a chamber as a solidified particulate collection means. The shape of the conveyance flow path 12 is a square cross section having a short side direction of 10 mm and a long side direction of 110 mm.
The carrier airflow 70 is supplied in a direction substantially orthogonal to the direction in which the droplets 21 are ejected from the droplet ejection means 11 and diffuses while bending the trajectory of the droplets 21 to prevent coalescence. .
The carrier airflow 70 generated by the Roots blower as the carrier airflow generating means adjusts the airflow rate of the blower so that the airflow velocity at the carrier airflow introduction unit 64 is 10 m / s. The flow is rectified by the honeycomb material of the conveying air flow introducing portion 64.

In order to prevent droplets from adhering to the wall surface, the transport flow path 12 has an expansion portion 73, and the auxiliary airflow means generates an auxiliary airflow 71 along the wall surface of the expansion portion 73.
The expansion part 73 has a structure in which both sides of the transport channel 12 are enlarged by 10 mm stepwise. The auxiliary airflow is introduced after being adjusted from the auxiliary airflow introduction portion 72 having a height of 5 mm so that the airflow velocity becomes 1 m / s. With this configuration, an auxiliary airflow that flows in the reverse direction from the downstream side to the upstream side of the carrier airflow 70 is formed near the wall surface of the extension 73, and the droplets 21 carried by the carrier airflow 70 flow in the wall direction. Can be suppressed and adhesion to the wall surface can be reduced.
The extended portion 73 has a rectangular cross section with a height of 45 mm and a width of 110 mm, and the droplet discharge means 11 is disposed at a height of 55 mm from the chamber.

The toner was collected using the solidified particle collecting means shown in FIG.
The chamber 61 has a cylindrical shape with an inner diameter (diameter) of 300 mm and a height of 2000 mm, and is fixed vertically, and its upper end and lower end are narrowed. The upper end portion of the chamber 61 is connected to the transport flow path 12 provided with the droplet discharge means 11 on the wall surface, and a cyclone collector which is a toner collecting portion is installed at the lower end portion.

Using the above-described toner production apparatus, toner production was carried out for a total of 8 hours. Then, when the wall surface of the conveyance flow path 12 was confirmed, adhesion of the droplet 21 was hardly seen.
Further, as the collection rate (toner recovery rate), the ratio of the weight of the collected toner to the solid content of the toner composition liquid discharged from the droplet discharge device was 90% or more.

[Example 2 (second embodiment)]
Toner was manufactured in the same manner as in Example 1 except that the transport solidifying unit having the configuration shown in FIG. In addition, the gradient of the reverse taper shape of the expansion part 73 is 45 degrees.
After manufacturing for a total of 8 hours, when the wall surface of the conveyance flow path 12 was confirmed, adhesion of the droplet 21 was hardly seen.
Further, as the collection rate (toner recovery rate), the ratio of the weight of the collected toner to the solid content of the toner composition liquid discharged from the droplet discharge device was 90% or more.

[Example 3 (third embodiment)]
Toner was manufactured in the same manner as in Example 1 except that the transport solidifying unit having the configuration shown in FIG. 9 was used as the transport solidifying unit. Note that the height of the stepped enlarged portion of the extended portion 73 is 20 mm, and the gradient of the reverse tapered shape is 45 degrees.
After manufacturing for a total of 8 hours, when the wall surface of the conveyance flow path 12 was confirmed, adhesion of the droplet 21 was hardly seen.
Further, as the collection rate (toner recovery rate), the ratio of the weight of the collected toner to the solid content of the toner composition liquid discharged from the droplet discharge device was 90% or more.

[Example 4 (fourth embodiment)]
Toner was manufactured in the same manner as in Example 1 except that the transport solidifying unit having the configuration shown in FIG. 10 was used as the transport solidifying unit. In addition, the gradient of the reverse taper shape of the expansion part 73 is 45 degrees.
After manufacturing for a total of 8 hours, when the wall surface of the conveyance flow path 12 was confirmed, adhesion of the droplet 21 was hardly seen.
There wasn't.
Further, as the collection rate (toner recovery rate), the ratio of the weight of the collected toner to the solid content of the toner composition liquid discharged from the droplet discharge device was 90% or more.

[Comparative Example 1]
The toner was manufactured in the same manner as in Example 1 except that the transport solidifying unit having the configuration shown in FIG. 11 was used as the transport solidifying unit.
After manufacturing for a total of 8 hours, the wall surface of the transport channel 12 was confirmed, and a large amount of droplets 21 was found on the downstream side of the transport channel 12.
The transport solidifying means in FIG. 11 is not provided with an auxiliary air flow generating means and is not provided with an extension, so that the flow velocity of the transport air flow 70 in the transport flow path 12 is larger on the center side than on the wall side. It is considered that the droplets 21 could not be controlled and could not be prevented from adhering to the wall surface of the transport channel 12.
Further, as the collection rate (toner recovery rate), the ratio of the weight of the collected toner to the solid content of the toner composition liquid ejected from the droplet ejection device was found to be less than 50%.

[Comparative Example 2]
The toner was manufactured in the same manner as in Example 1 except that the transport solidifying means of FIG. 7 was used as the transport solidifying means and the conditions were such that no auxiliary airflow was generated.
After manufacturing for a total of 8 hours, when the wall surface of the conveyance flow path 12 was confirmed, adhesion of the droplet 21 on the wall surface of the extended part 73 was seen a lot.
Since the auxiliary airflow is not generated, the flow velocity of the carrier airflow 70 in the carrier channel 12 cannot be controlled to be larger on the center side than on the wall side, and the backstep flow generated in the expansion portion 73 It is considered that it was not possible to prevent the droplets 21 that had been on them from adhering to the wall surface.
Further, as a collection rate (toner recovery rate), the ratio of the weight of the collected toner to the solid content of the toner composition liquid discharged from the droplet discharge device was found to be less than 60%.

  As described above, according to the fine particle production apparatus and the fine particle production method of the present embodiment, in the production of particles by spray granulation, adhesion of droplets to the wall surface is prevented, and maintainability is ensured and high productivity is achieved. It is feasible.

DESCRIPTION OF SYMBOLS 1 Fine particle manufacturing apparatus 11 Droplet discharge means 12 Conveyance flow path 13 Toner composition liquid tank 14 Toner composition liquid 17 Liquid common supply path 18 Liquid column resonance liquid chamber 19 Discharge hole 20 Vibration generating means 61 Chamber 62 Toner collection part (solidified particle) Collection part)
63 Toner reservoir (solidified particle reservoir)
64 Carrying airflow introduction part 65 Carrying airflow discharge part 70 Carrying airflow 71 Auxiliary airflow 72 Auxiliary airflow introduction part 73 Expansion part

JP 2011-212668 A JP 2013-077876 A

Claims (10)

There are at least a droplet discharge unit that discharges the fine particle raw material-containing liquid as droplets from at least one discharge hole, and a transport solidification unit that transports and solidifies the droplets discharged by the droplet discharge unit by a transport airflow. And
The transport solidifying means includes a transport flow path serving as a flow path for the droplets and the transport air current, a transport air flow generating means for generating the transport air current, and an auxiliary flow from the downstream side to the upstream side in the transport direction of the droplets. An auxiliary airflow generating means for generating an airflow,
The fine particle manufacturing apparatus according to claim 1, wherein the transport flow path has an expanded portion whose cross-sectional area is expanded toward the downstream side, and the auxiliary airflow flows along a wall surface of the expanded portion.   2. The fine particle manufacturing apparatus according to claim 1, wherein the flow velocity of the carrier airflow in the carrier channel is relatively larger at the center side than at the wall side at least in the extended portion.   The fine particle manufacturing apparatus according to claim 1, wherein the extension portion has a cross-sectional shape having a reverse taper shape.   The fine particle manufacturing apparatus according to any one of claims 1 to 3, wherein a flow velocity of the auxiliary airflow is smaller than a flow velocity of the carrier airflow. The droplet discharge means includes a liquid column resonance liquid chamber in which the discharge hole is formed, and a vibration generating unit that applies vibration to the fine particle material-containing liquid in the liquid column resonance liquid chamber;
The vibration generating unit applies vibration to the fine particle raw material-containing liquid in the liquid column resonance liquid chamber to form a pressure standing wave by liquid column resonance, and is formed in a region that becomes an antinode of the pressure standing wave. The fine particle manufacturing apparatus according to claim 1, wherein the fine particle raw material containing liquid is discharged from a discharge hole.   The fine particle manufacturing apparatus according to claim 5, wherein a plurality of the discharge holes are formed in the liquid column resonance liquid chamber.   The apparatus for producing fine particles according to claim 1, wherein the fine particles are toner. A droplet discharge step of discharging a liquid containing a fine particle material as droplets from a droplet discharge unit having at least one discharge hole, and a transport solidification step of transporting and solidifying the droplets discharged in the droplet discharge step by a transport solidification unit Including
The transport solidifying means includes a transport flow path serving as a flow path for the droplets and the transport air flow, a transport air flow generating means for generating the transport air flow, and a transport direction of the droplets along the wall surface of the transport flow path. An auxiliary airflow generating means for generating an auxiliary airflow that flows from the downstream side to the upstream side, and the conveyance flow path has an expanded portion whose cross-sectional area is expanded toward the downstream side,
In the conveying and solidifying step, the auxiliary airflow is formed along the wall surface of the extension portion.   In the said conveyance solidification process, the flow velocity of the said conveyance airflow in the said conveyance flow path is controlled so that it may become relatively larger by the center side rather than the wall side at least in the said expansion part. The fine particle manufacturing method as described.   A toner produced by the fine particle production method according to claim 8.