JP6156775B2 - Fine particle production method, fine particle production apparatus, and electrophotographic toner - Google Patents

Description

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

Conventionally, as a method for producing an electrostatic charge image developing toner used in a copying machine, a printer, a fax machine, and a composite machine based on an electrophotographic recording method, only a pulverization method has been used in recent years. The method of forming toner particles in an aqueous medium has been widely used, and is surpassing the pulverization method. The toner produced by the polymerization method is called “polymerized toner” or “chemical toner” in some countries.
The polymerization method is referred to as such because it involves the polymerization reaction of the toner raw material at the time of toner particle formation or in the process. Various polymerization methods have been put into practical use and include suspension polymerization, emulsion aggregation, polymer suspension (polymer aggregation), ester elongation reaction, and the like.

  The toner obtained by the polymerization method is generally easier to obtain a toner having a smaller particle size than the toner obtained by the pulverization method, has a narrow particle size distribution, and has a shape close to a sphere. An image in the photographic system has an advantage that it is easy to obtain high image quality. However, on the other hand, it takes a long time for the polymerization process, and after completion of solidification, it is necessary to separate the solvent and toner particles, and then repeat washing and drying, which requires a lot of time, a lot of water and energy. There is.

Therefore, there is known a jet granulation method in which a liquid in which a raw material component of toner is dissolved or dispersed in an organic solvent (hereinafter referred to as toner component liquid) is finely divided using various atomizers and then dried to obtain a powdery toner. (For example, refer to Patent Documents 1 to 3). According to this method, since it is not necessary to use water, steps such as washing and drying can be greatly reduced, so that the disadvantages of the polymerization method can be avoided.
In the toner manufacturing methods disclosed in Patent Documents 1 to 3, droplets corresponding to the nozzle diameter are discharged from the nozzle. In this method, after the toner component liquid is sprayed, the droplets coalesce before the formed droplets are dried, and the solvent is dried in that state to obtain a toner, so that the resulting toner The particle size distribution was inevitably widened, and the particle size distribution was not satisfactory.

With respect to such a problem, the toner production method by jet granulation described in Patent Document 4 proposed by the present applicant does not require a large amount of cleaning liquid, repeated separation of solvent and particles, and is extremely efficient in production. Toner with high particle size, energy saving, and narrow particle size distribution.
However, this apparatus has a problem that the resin composition liquid is subjected to high-frequency vibration and bubbles are generated in the resin composition liquid, so that droplet discharge cannot be performed normally.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a fine particle production method capable of stably forming droplets by a jet granulation method.

  The present inventors have stated that the above problem is that when the resin composition liquid for producing fine particles is jetted and granulated, the resin composition liquid is filled into a flexible container so that no gas enters, and the resin composition is transferred from the flexible container to the droplet discharge unit. The present invention finds out that the present invention can be solved by supplying the liquid and setting the amount of dissolved oxygen in the resin composition liquid in the flexible container to be equal to or less than half the amount of dissolved oxygen when the resin composition liquid is saturated with air. Completed.

The above-mentioned problem is related to the present invention “Supplying a fine particle composition solution obtained by dissolving or dispersing at least a resin-containing composition in a solvent to a droplet discharge unit that continuously discharges from one or more discharge holes into droplets In the method for producing fine particles, the method includes a droplet forming step for forming the droplet composition liquid into droplets, and a droplet solidifying step for solidifying the droplets by drying a solvent of the droplet composition solution. The droplet forming step forms a standing wave by liquid column resonance by applying high frequency vibration to the fine particle composition liquid in the liquid column resonance liquid chamber in which one or more discharge holes are formed, and pressure fluctuation of the standing wave Is a step of discharging the fine particle composition liquid into droplets from the discharge holes arranged in a region having an amplitude large enough to discharge the liquid,
A method for producing fine particles, which satisfies the following requirements A and B.
A. The resin composition liquid is filled into a flexible container so that gas does not enter, and the resin composition liquid is supplied from the flexible container to the droplet discharge unit.
B. The amount of dissolved oxygen in the resin composition liquid in the flexible container is ½ or less of the amount of dissolved oxygen when the resin composition liquid is saturated with air. "
Can be solved by.

  According to the present invention, even when the resin composition liquid is subjected to high-frequency vibrations in the droplet discharge unit, no bubbles are generated, so that excellent droplet discharge can be performed.

It is sectional drawing which shows the structure of a liquid column resonance droplet formation means. It is sectional drawing which shows the structure of a liquid column resonance droplet unit. It is sectional drawing of a discharge outlet. It is the schematic which shows the standing wave of the speed and pressure fluctuation in the case of N = 1,2,3. It is the schematic which shows the standing wave of the speed and pressure fluctuation in the case of N = 4 and 5. 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 liquid column resonance droplet formation means. It is a characteristic view which shows a drive frequency and a droplet discharge speed frequency characteristic. It is the schematic of the microparticle manufacturing apparatus of this invention. It is a conceptual diagram which shows the method of preventing coalescence of the microparticles | fine-particles after discharge. It is the schematic of the conventional fine particle manufacturing apparatus.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated based on drawing. Note that it is easy for a person skilled in the art to make other embodiments by changing or correcting the present invention within the scope of the claims, and these changes and modifications are included in the scope of the claims. The following description exemplifies an embodiment of the present invention, and does not limit the scope of the claims.

  An example of an apparatus used for carrying out the toner manufacturing method of the present invention will be described below with reference to FIGS. An apparatus used for carrying out the method for producing fine particles of the present invention includes a droplet discharge means and a droplet solidification collecting means. Each is explained below.

[Droplet discharge unit]
The droplet discharge unit (droplet discharge means) used in the present invention is not particularly limited as long as the particle size distribution of the discharged droplets is narrow, and a known one can be used. Examples of the droplet discharge means include one-fluid nozzle, two-fluid nozzle, membrane vibration type discharge means, Rayleigh split type discharge means, liquid vibration type discharge means, liquid column resonance type discharge means, and the like. Japanese Patent Application Laid-Open No. 2008-292976, Rayleigh splitting type is described in Japanese Patent No. 4647506, and liquid vibration type is described in Japanese Patent Application Laid-Open No. 2010-102195.
In order to secure the productivity of fine particles with a narrow droplet size distribution, vibration is applied to the liquid in the liquid column resonance liquid chamber in which multiple discharge holes are formed to form a standing wave by liquid column resonance. However, there is a liquid droplet resonance that discharges liquid from the discharge hole formed in the region that becomes the antinode of the standing wave, and any of these is preferably used.

[Liquid column resonance droplet discharge means]
The liquid column resonance type discharge means that discharges using the resonance of the liquid column will be described.
FIG. 1 shows a liquid column resonance droplet discharge means 11. In the present invention, a unit in which a plurality of liquid column resonance droplet discharge means are integrated may be referred to as a liquid column resonance droplet discharge unit.
The liquid column resonance droplet discharge means 11 includes a liquid common supply path 17 and a liquid column resonance liquid chamber 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 (not shown).

In the present invention, the liquid discharged from the discharge means is in a dispersed state in which the components of the fine particles to be obtained are dissolved or dispersed. In the present invention, a liquid containing a component that forms fine particles is referred to as a “fine particle composition liquid”.
The fine particle composition liquid 14 passes through a liquid supply pipe by a liquid circulation pump (not shown) and flows into the liquid common supply path 17 of the liquid column resonance droplet forming unit 10 shown in FIG. 2, and the liquid column resonance droplet shown in FIG. It is supplied to the liquid column resonance liquid chamber 18 of the discharge means 11. In the liquid column resonance liquid chamber 18 filled with the fine particle 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.

  The fine particle composition liquid 14 that has passed through the liquid common supply path 17 flows through a liquid return pipe (not shown) and is returned to the raw material container. When the amount of the toner component 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 component liquid 14 supplied from the path 17 increases, and the toner component liquid 14 is replenished into the liquid column resonance liquid chamber 18. When the toner component liquid 14 is replenished in the liquid column resonance liquid chamber 18, the flow rate of the toner component liquid 14 passing through the liquid common supply path 17 is restored.

  Each of the liquid column resonance liquid chambers 18 in the liquid column resonance droplet discharge means 11 has 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. It is formed by bonding. Further, as shown in FIG. 1, 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, the width W of the liquid column resonance liquid chamber 18 shown in FIG. 2 is desirably smaller than one 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. . Furthermore, it is preferable that a plurality of liquid column resonance liquid chambers 18 are arranged for one droplet forming unit 10 in order to dramatically improve productivity. The range is not limited, but one droplet forming unit provided with 100 to 2000 liquid column resonance liquid chambers 18 is most preferable because both operability and productivity can be achieved. In addition, for each liquid column resonance liquid chamber, a flow path for supplying liquid is connected from the common liquid supply path 17, and a plurality of liquid column resonance liquid chambers 18 are connected to the common liquid supply path 17. .

Further, the vibration generating means 20 in the liquid column resonance 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 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. Furthermore, 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. In addition, the block-shaped vibrating member made of one material is partially cut in accordance with the arrangement of the liquid column resonance liquid chambers, and each liquid column resonance liquid chamber can be individually controlled via an elastic plate. desirable.

  Furthermore, the diameter of the opening of the discharge hole 19 is desirably in the range of 1 [μm] to 40 [μm]. If the particle size is smaller than 1 [μm], the formed droplets may be very small, so that the toner may not be obtained. In the case of a configuration in which solid fine particles such as pigment are contained as a component of the toner, the discharge hole 19 There is a risk that productivity will be reduced due to frequent blockages. In addition, when it is larger than 40 [μm], the diameter of the droplet is large, and when this is dried and solidified to obtain a desired toner particle diameter of 3 to 6 μm, it is necessary to dilute the toner composition to a very dilute liquid with a solvent. In some cases, a large amount of drying energy is required to obtain a certain amount of toner, which is inconvenient. Further, as can be seen from FIG. 2, adopting a configuration in which the discharge holes 19 are provided in the width direction in the liquid column resonance liquid chamber 18 can provide a large number of openings of the discharge holes 19, thereby increasing the production efficiency. Therefore, it is preferable. 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 sectional shape of the discharge hole 19 is described as a tapered shape in which the diameter of the opening is reduced in FIG. 1 and the like, but the sectional shape can be appropriately selected.
FIG. 3 shows a cross-sectional shape that the discharge hole 19 can take. (A) has a shape in which the opening diameter becomes narrow while having a round shape from the liquid contact surface of the discharge hole 19 toward the discharge port, and near the outlet of the discharge hole 19 when the thin film 41 vibrates. Since the pressure applied to the liquid is maximized, it is the most preferable shape for stabilizing the discharge.
(B) has 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 increased in the vicinity of the outlet of the discharge hole 19 when the thin film 41 vibrates by this nozzle angle similar to (a), but the range of 60 to 90 ° is preferable. When the angle is 60 ° or less, it is difficult to apply pressure to the liquid and it is difficult to process the thin film 41. When the nozzle angle 24 is 90 °, (c) corresponds, but it is difficult to apply pressure to the outlet, so 90 ° is the maximum value. If the angle is 90 ° or more, no pressure is applied to the outlet of the hole 12, so that the droplet discharge becomes very unstable.
(D) is a combination of (a) and (b). In this way, the shape may be changed step by step.

Next, the mechanism of droplet formation by the droplet formation unit in liquid column resonance will be described.
First, the principle of the liquid column resonance phenomenon occurring in the liquid column resonance liquid chamber 18 in the liquid column resonance droplet discharge means 11 of FIG. 1 will be described. The sound velocity of the toner component liquid in the liquid column resonance liquid chamber is c, and vibration is generated. When the drive frequency given from the means 20 to the toner component liquid, which is a medium, is f, the wavelength λ at which the liquid resonance occurs is expressed by the following formula 1.
λ = c / f (Formula 1)

Further, in the liquid column resonance liquid chamber 18 of FIG. 1, the length from the end of the frame on the fixed end side to the end on the common liquid supply path 17 side is L, and further, the end of the frame on the common liquid supply path 17 side The height h1 (= about 80 [μm]) is about twice the height h2 (= about 40 [μm]) of the communication port, and the fixed ends on both sides are assumed to be equivalent to the fixed end closed. In this case, resonance is formed most efficiently when the length L coincides with 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 driving frequency f with the highest efficiency is expressed by the following equation 3 from the above equations 1 and 2.
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, and 3. 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. 3A showing the case of a 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 at which the moving speed of the medium (liquid) in the longitudinal direction becomes zero, and conversely, the pressure becomes maximum. 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 it is completely equivalent to the fixed ends on both sides. When N = 2 resonance mode is used, the most efficient resonance frequency is derived from the above equation (2) as 324 kHz. 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 there are wall surfaces at both ends using the same conditions as described above. Thus, when N = 4 resonance mode equivalent to the fixed ends on both sides is used, the most efficient resonance frequency is derived from the above formula (2) as 648 kHz, and even in the liquid column resonance liquid chamber having the same configuration, Higher order resonances can be used.

  The liquid column resonance liquid chamber 18 in the liquid column resonance droplet discharge means 11 shown in FIG. 1 can be described as an acoustically soft wall because both ends are equivalent to the closed end state or due to the influence of the opening of the discharge hole. Although it is preferable that it is an end part in order to raise a frequency, it is not restricted to this, An open end may be sufficient. 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 of the length L between both ends in the longitudinal direction of the liquid column resonance liquid chamber to the distance Le to the discharge hole closest to the end on the liquid supply side is preferably Le / L> 0.6.

A liquid column resonance pressure standing wave is formed in the liquid column resonance liquid chamber 18 of FIG. 1 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 for 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, it is preferably between 2 and 100.
When the number exceeds 100, if a desired droplet is to be formed from the 100 ejection holes 19, it is necessary to set a high voltage to the vibration generating means 20, and the behavior of the piezoelectric body as the vibration generating means 20 is increased. 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. 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 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 in the droplet discharge head in the droplet forming unit will be described with reference to FIG. In the figure, the solid line drawn in the liquid column resonance liquid chamber represents the velocity distribution plotting the velocity at any measurement position from the fixed end side to the liquid common supply path side end in the liquid column resonance liquid chamber. The direction from the common liquid supply path to the liquid column resonance liquid chamber is +, and the opposite direction is −. In addition, the dotted line marked in the liquid column resonance liquid chamber indicates a pressure distribution in which the pressure value at each arbitrary measurement position between the fixed end side and the liquid common supply path side end in the liquid column resonance liquid chamber is plotted. The positive pressure is + with respect to the atmospheric pressure, and the negative pressure is-. Moreover, if it is a positive pressure, a pressure will be applied to the downward direction in the figure, and if it is a negative pressure, a pressure will be applied to the upward direction in the figure. Further, in the same figure, the liquid common supply path side is opened as described above, but the height of the opening where the liquid common supply path 17 and the liquid column resonance liquid chamber 18 communicate with each other (height h2 shown in FIG. 1). On the other hand, since the height of the frame serving as the fixed end (height h1 shown in FIG. 1) is about twice or more, the approximate condition is that the liquid column resonance liquid chamber 18 is substantially fixed at both sides. The change in the velocity distribution and the pressure distribution over time is shown.

FIG. 6A shows a pressure waveform and a velocity waveform in the liquid column resonance liquid chamber 18 when droplets are discharged.
In FIG. 6B, the meniscus pressure increases again after the liquid is drawn immediately after the droplet is discharged. As shown in FIGS. 4A and 4B, 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. 6C, the positive pressure in the vicinity of the ejection hole 19 decreases, and the liquid droplet 21 is ejected in a negative pressure direction.

  Then, as shown in FIG. 6D, the pressure in the vicinity of the discharge hole 19 is minimized. From this time, filling of the liquid component resonance liquid chamber 18 with the toner component liquid 14 starts. Thereafter, as shown in FIG. 6E, the negative pressure in the vicinity of the discharge hole 19 becomes smaller and shifts to the positive pressure direction. At this time, the filling of the toner component 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, an example of a configuration in which droplets are actually ejected by the liquid column resonance phenomenon will be described. This example is a resonance mode in which the length L between both ends in the longitudinal direction of the liquid column resonance liquid chamber 18 in FIG. 1 is 1.85 [mm] and N = 2, and the first to fourth discharge holes are provided. FIG. 7 shows a state in which an ejection hole is arranged at the antinode of the N = 2 mode pressure standing wave and the ejection performed by a sine wave with a driving frequency of 340 [kHz] is photographed by a laser shadowgraphy method. As can be seen from the figure, it was possible to discharge droplets with very uniform diameters and almost uniform speeds.

  FIG. 7 is a characteristic diagram showing droplet velocity frequency characteristics when driven by the same amplitude sine wave with a drive frequency of 290 [kHz] to 395 [kHz]. As can be seen from the figure, the discharge speed from each nozzle is uniform and the maximum discharge speed when the drive frequency is around 340 [kHz] in the first to fourth nozzles. From this result, it can be seen that, in the second mode of the liquid column resonance frequency, 340 [kHz], uniform ejection is realized at the antinode position of the liquid column resonance standing wave. Further, from the characteristic results of FIG. 7, the droplet is between the droplet discharge speed peak at 130 [kHz] which is the first mode and the droplet discharge speed peak at 340 [kHz] which is the second mode. It can be seen that the characteristic frequency characteristic of the liquid column resonance standing wave of the liquid column resonance that does not discharge is generated in the liquid column resonance liquid chamber.

[Degassing of resin composition liquid]
As described above, the resin composition liquid in the present invention is subjected to high-frequency vibrations in the droplet discharge unit. For this reason, the air melt | dissolved in the resin composition liquid turns into gas, and a bubble may generate | occur | produce. In the case of the liquid column resonance ejection means, bubbles enter the liquid column resonance chamber, so that proper liquid column resonance cannot be obtained and droplet ejection cannot be performed normally. By degassing the air in the resin composition liquid, the generation of bubbles in the liquid column resonance chamber can be prevented.
In managing the degree of deaeration of air in the resin composition liquid, it is preferable to manage the amount of dissolved oxygen in the resin composition liquid. This is because the measurement of the amount of dissolved oxygen in the solution is simpler and more accurate than the measurement of the amount of dissolved nitrogen.
Generation of bubbles in the liquid column resonance chamber can be suppressed if the amount of dissolved oxygen is equal to or less than ½ when the resin composition solution is saturated with air.
Since the condition for saturated dissolution of air in the resin composition liquid is the state when droplets are discharged, the apparatus shown in FIG. 8 to be described later has the same temperature as the droplet discharge unit 2 at the pressure indicated by the pressure of the pressure gauge P2. It is a saturated state when

[Deaeration means]
A means for removing air dissolved in the resin composition liquid (hereinafter, deaeration means) used in the present invention will be described. The deaeration means described here is an example, and the present invention is not limited to these.
It is preferable to maintain the degassing state of the resin composition liquid by removing dissolved gas by the following degassing method and then hermetically packaging with a material having a high gas barrier property.
A vacuum degassing method can be used as the first degassing means. The vacuum degassing method is a method in which the inside of a container containing a resin composition liquid is depressurized by a suction pump and the dissolved gas is discharged. It is desirable that the resin composition liquid is stirred during the decompression treatment. Alternatively, deaeration is also promoted by applying ultrasonic vibration and reducing the pressure while generating cavitation. Moreover, deaeration is accelerated | stimulated also by heating a resin composition liquid.
As a second degassing method, the resin composition solution is passed through a tube formed of a hollow fiber membrane, and only the gas is discharged out of the tube by decompressing the outer periphery of the tube. While continuously applying this degassing method, it is possible to supply the resin composition liquid to the outside.

[Flexible container]
In the present invention, the degassed resin composition liquid is filled in a flexible container without containing gas and supplied to the droplet discharge unit. Since the resin composition liquid is present in the flexible container without being in direct contact with the gas, the gas is not dissolved in the resin composition liquid, and the deaerated state is maintained. In addition, since the flexible container is deformed and the volume is freely changed, even if the resin composition liquid is increased or decreased, the pressure in the container is hardly changed, and pressure adjustment is easy.
On the other hand, in the case of a non-flexible resin composition liquid container such as the raw material container 13 of FIG. 10, the resin composition liquid and the gas are in contact with each other, so that the gas dissolves in the resin composition liquid and keeps the deaerated state. Is difficult.

Existing flexible containers can be used. Any bag can be used as long as it can hold a liquid by forming a bag with a flexible film. As an example of the film, if the inner side is formed of a polyethylene film, it can be welded by heat sealing or the like, and the container can be easily formed. In consideration of gas permeability, a multilayer film in which a metal foil layer (aluminum foil or the like) or a film having low gas permeability is bonded to a polyethylene film can also be used. In consideration of strength, a multilayer film in which PET or nylon is bonded to a polyethylene film can also be used.
Moreover, when the solvent of a resin composition liquid is an organic solvent, it is desirable to use a flexible film and an adhesive with a high solvent resistance.

[Droplet solidification]
The particles of the present invention can be obtained by solidifying and then collecting the droplets of the fine particle composition liquid discharged into the gas from the droplet discharge means described above.

[Droplet solidification means]
Solidification can be achieved by drying the droplets in the carrier airflow after jetting the droplets, that is, volatilizing the solvent. In drying the solvent, the drying state can be adjusted by appropriately selecting the temperature, vapor pressure, gas type, and the like of the gas to be injected. Further, even if the particles are not completely dried, they may be additionally dried in a separate step after the collection as long as the collected particles maintain a solid state.

[Solidification particle collection means]
The solidified particles can be recovered from the air by a known powder collecting means such as cyclone collecting or a back filter.

The fine particle production apparatus of the present invention continuously discharges the fine particle composition liquid from a flexible container containing a fine particle composition liquid obtained by dissolving or dispersing at least a resin-containing composition in a solvent, and one or more discharge holes. A droplet discharge unit for forming droplets, a means for supplying the droplet composition liquid in the flexible container to the droplet discharge unit, and a liquid for solidifying the droplets by drying the solvent of the droplet composition solution formed into droplets A droplet solidifying means, and the droplet discharge unit is provided with a high frequency vibration to the fine particle composition liquid in the liquid column resonance liquid chamber in which the one or more discharge holes are formed, thereby standing by liquid column resonance. A unit for forming a wave and discharging the fine particle composition liquid into droplets from the discharge holes disposed in a region where the pressure fluctuation of the standing wave has an amplitude large enough to discharge the liquid. Yes, the full Dissolved oxygen amount of the resin composition liquid Kishiburu vessel, the resin composition liquid is characterized in that there is a half or less of the amount of dissolved oxygen when the saturated dissolved air.
FIG. 8 is a cross-sectional view of an example of an apparatus for carrying out the method for producing fine particles of the present invention. The toner manufacturing apparatus 1 mainly includes a droplet discharge unit 2 and a dry collection unit 60.
The droplet discharge unit 2 is supplied to the droplet discharge unit 2 through the liquid supply pipe 16 and the flexible container 25 storing the resin composition liquid 14 and the fine particle composition liquid 14 stored in the flexible container 25. The liquid supply pipe 16 is provided with a pressure measuring instrument P1 (liquid pressure gauge), and the dry collecting means 60 is provided with a pressure measuring instrument P2 (pressure gauge in the chamber). The pressure in the dry collection unit is managed by pressure gauges P1 and P2. At this time, if the relationship of P1> P2, the fine particle composition liquid 14 may ooze out from the hole 12, and in the case of P1 <P2, there is a possibility that gas enters the discharge means and the discharge may stop. It is desirable that P1≈P2. In order to adjust the pressure of P1, the flexible container 25 is put in the pressure container 26, and the pressure is adjusted by the pressure adjusting air pump 27. Since the fine particle composition liquid 14 is contained in the flexible container 25, the pressure can be easily adjusted. Moreover, as a pressure adjusting method of P1, the pressure can be adjusted also by changing the height of the flexible container 25. By opening the pressure release valve 30 and changing the height of the flexible container 25, the pressure of P1 can be easily adjusted with high accuracy.
When the height of the flexible container 25 is increased, the pressure of P1 increases, and when the height of the flexible container 25 is decreased, the pressure of P1 decreases.

  When the resin composition liquid in the flexible container 25 decreases and becomes insufficient, the degassed resin composition liquid can be put through the resin composition liquid supply path 29 through the resin composition liquid supply valve 29. The resin composition liquid may be added even during the droplet discharge, and the capacity of the flexible container 25 can be easily changed. Therefore, there is almost no change in the pressure of P1 when the liquid is added, and the droplet discharge unit 2 Therefore, a good liquid supply can be continued.

The amount of the resin composition liquid in the flexible container 25 is preferably 10% to 90%, and more preferably 20% to 80% of the flexible container capacity. When the volume of the resin composition liquid is less than 10% of the volume of the flexible container, the pressure of P1 decreases due to the elasticity of the flexible container 25, which is not preferable. Moreover, when it exceeds 90%, since the pressure of P1 will rise by the elasticity of the flexible container 25, it is not preferable.
For this reason, when the appropriate liquid replenishment is performed so that the amount of the resin composition liquid in the flexible container is 10 to 90 vol%, the pressure of P1 is stable and preferable.

  In the chamber 61, a carrier airflow 101 created from the carrier airflow inlet 64 is formed. The droplets 21 ejected from the droplet ejection means 2 are transported downward not only by gravity but also by the transport airflow 101, and are collected by the particulate collection means 62 that collects solidified particulates. The fine particles collected by the fine particle collecting means 62 are collected in the fine particle reservoir 63.

[Conveyance airflow]
When the ejected droplets come into contact with each other before drying, the droplets coalesce and become one particle (hereinafter, this phenomenon is called coalescence). In order to obtain solidified particles having a uniform particle size distribution, it is necessary to maintain the distance between the ejected droplets. However, the ejected droplets have a constant initial velocity, but eventually become stalled due to air resistance. The jetted droplets catch up with the stalled particles and coalesce as a result. Since this phenomenon occurs constantly, the particle size distribution is greatly deteriorated when the particles are collected. In order to prevent coalescence, it is necessary to transport the liquid droplets while solidifying the droplets while preventing the liquid droplets from decreasing in speed and preventing the coalescence by the conveying airflow 101 so that the droplets do not contact each other. Carry the solidified particles to the collection means.

  For example, as shown in FIG. 8, a part of the transport airflow 101 is arranged as a first airflow in the vicinity of the droplet discharge means in the same direction as the droplet discharge direction, thereby reducing the droplet velocity immediately after the droplet discharge. Can be prevented and coalescence can be prevented. Alternatively, as shown in FIG. 9, the direction may be transverse to the ejection direction. Alternatively, although not shown, it may have an angle, and it is desirable to have an angle at which the droplets are separated from the droplet discharge means. As shown in FIG. 9, when the anti-adhesion airflow is applied from the lateral direction to the droplet discharge, it is desirable that the trajectories do not overlap when the droplets are conveyed by the anti-adhesion airflow from the discharge port. .

After preventing coalescence by the first air stream as described above, the solidified particles may be carried to the solidified particle collecting means by the second air stream.
It is desirable that the velocity of the first air flow is equal to or higher than the droplet jet velocity. If the speed of the anti-adhesion airflow is lower than the droplet ejection speed, it is difficult to exert the function of preventing the droplet particles, which is the original purpose of the anti-adhesion airflow, from contacting.
The property of the first air stream can be added with a condition such that the droplets do not coalesce with each other, and may not necessarily be the same as the second air stream. Further, a chemical substance that promotes solidification of the particle surface may be mixed in the anti-adhesion airflow, or may be imparted in anticipation of physical action.

  The carrier airflow 101 is not particularly limited as a state of the airflow, and may be a laminar flow, a swirl flow, or a turbulent flow. There is no particular limitation on the type of gas constituting the carrier airflow 101, and air or a nonflammable gas such as nitrogen may be used. Moreover, the temperature of the conveyance airflow 101 can be adjusted as appropriate, and it is desirable that there is no fluctuation during production. Further, means for changing the airflow state of the carrier airflow 101 may be provided in the chamber 61. The carrier airflow 101 may be used not only to prevent the droplets 21 from being attached to each other but also to prevent the droplets 21 from adhering to the chamber 61.

[Secondary drying]
When the amount of residual solvent contained in the fine particles obtained by the dry collection means shown in FIG. 8 is large, secondary drying is performed as necessary to reduce this. As the secondary drying, general known drying means such as fluidized bed drying or vacuum drying can be used. If the solvent remains in the toner, not only the toner characteristics such as heat-resistant storage stability, fixability, and charging characteristics change with time. Since the solvent evaporates at the time of fixing by heating, the possibility of adversely affecting the user and peripheral equipment is increased. Therefore, sufficient drying is performed.

  The present invention relates to a method for producing fine particles, but the fine particles can also be used as an electrophotographic toner. The description as a toner is described below. Naturally, fine particles other than toner can be produced by appropriately selecting the components.

The toner of the present invention contains at least a resin, and optionally contains a colorant, a wax, a charge adjusting agent, an additive, and other components.
The “toner component liquid” used in the present invention will be described. The toner component liquid is in a liquid state in which the toner component is dissolved or dispersed in a solvent.
As the toner material, if the toner component liquid described above can be adjusted, the same material as the conventional electrophotographic toner can be used. As described above, the droplets are made into fine droplets by the droplet discharge means, and the target toner particles can be produced by the droplet solidification collecting means.

〔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 to dissolve in a solvent, and it is desirable to have a conventionally known performance except for this feature.

[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 also preferable, and the binder resin has at least one peak in a molecular weight region of 5,000 to 20,000. Is more preferable.

[Acid value of binder resin]
What has 60 [mass%] or more of resin whose acid value of binder resin has 0.1-50 [mgKOH / g] 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.

  In the case where the fine particles of the present invention are used as a magnetic toner, a known magnetic material conventionally used for an electrophotographic toner 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], 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.

[Colorant]
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] based on the toner.

The colorant used in the toner according to the present invention 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” (Ajinomoto Fine). Techno), “Disperbyk-2001” (by Big Chemie), “EFKA-4010” (by EFKA), and the like.

The dispersant is preferably blended in the toner at a ratio of 0.1 to 10 [mass%] with respect to the colorant. When the blending ratio is less than 0.1 [% by mass], the pigment dispersibility may be insufficient, and when more than 10 [% by mass], the chargeability under high humidity may be deteriorated.
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 component liquid used in the present invention 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 [° C.], the blocking resistance may be lowered, and if it exceeds 140 [° C.], the offset resistance effect may be difficult to be exhibited.
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.

<Solvent>
The solvent is not particularly limited as long as it can dissolve the binder resin and stably disperse the dispersion such as the colorant and the release agent, and can be appropriately selected according to the purpose. A solvent that can be easily dried is preferable because it is used when a toner is produced by droplet formation in the medium. From the viewpoint of drying, the boiling point of the solvent is preferably 100 ° C. or less because the drying speed is fast.
As the solvent, for example, ethers, ketones, esters, hydrocarbons, and alcohols are preferable, and tetrahydrofuran (THF), acetone, methyl ethyl ketone (MEK), ethyl acetate, and toluene are more preferable. These may be used individually by 1 type and may use 2 or more types together.

The solid content concentration of the fine particle composition liquid in the present invention is not limited as long as droplet formation can be performed normally. However, the solid content concentration of the fine particle composition liquid is preferably low and is preferably 30% or less. More preferably, it is 5 to 20%.
Since the solvent is volatilized from the fine particle composition liquid after the droplet discharge is started and converted into fine particles, the change in physical properties such as the solution viscosity, the sound speed of the liquid, and the surface tension of the liquid need not be changed greatly. Therefore, it is preferable that the solid content concentration of the fine particle composition liquid is low. However, if the solid content concentration of the fine particle composition liquid is too low, the drying energy and the like increase, which is not preferable because the production efficiency decreases.

  In the toner according to the present invention, 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 weight] of the toner, and more preferably 0.01 to 2.0 [% by weight].

  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].

Next, the formulation of the dissolution or dispersion used in the embodiment is shown.
The injection conditions are as described later.

<Preparation of solution of styrene-n-butyl acrylate copolymer resin>
9 parts by mass of ethyl acetate was mixed with 1 part by mass of the styrene-n-butyl acrylate copolymer resin, and the resin was completely dissolved to prepare a styrene-n-butyl acrylate copolymer resin solution. The styrene-n-butyl acrylate copolymer resin had a mass average molecular weight of 45,000 and a glass transition temperature of 59 ° C.

<Preparation of colorant dispersion>
Carbon black (Regal 400, manufactured by Cabot) 20 parts by mass and pigment dispersant 2 parts by mass were primarily dispersed in 78 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 was finely dispersed by a strong shearing force using a dyno mill to prepare a secondary dispersion from which aggregates were completely removed. Further, a dispersion was prepared by passing through a polytetrafluoroethylene filter having 1 μm pores and dispersing to a submicron region.

<Preparation of carnauba wax dispersion>
Carnauba wax (manufactured by Toa Kasei Co., Ltd.) 1 part by weight and ethyl acetate 4 parts by weight were charged, heated to 85 ° C. and stirred for 20 minutes to dissolve the carnauba wax, and then rapidly cooled to precipitate carnauba wax fine particles. . This carnauba wax dispersion was further finely dispersed by a strong shearing force using a star mill LMZ06 (manufactured by Ashizawa Finetech Co., Ltd.) filled with zirconia beads having a diameter of 0.1 μm, and the average particle size of carnauba wax was 0.3 μm. The maximum particle size was adjusted to 0.8 μm or less. For measuring the particle size of the carnauba wax, NPA150 manufactured by Microtrac was used.

<Preparation of toner composition liquid>
1000 parts by mass of a solution of styrene-n-butyl acrylate copolymer resin, 25 parts by mass of a colorant dispersion, 50 parts by mass of a carnauba wax dispersion, and 80 parts by mass of ethyl acetate were mixed. This mixed liquid was passed through a filter having an opening of 1 μm to prepare a toner composition liquid 1 having a solid content of 10%.

-Toner production equipment-
Toner was manufactured using the toner manufacturing apparatus 1 having the configuration shown in FIGS.
FIG. 10 is a diagram showing an apparatus used in a comparative example.
The apparatus shown in FIG. 10 includes the same droplet discharge unit 2 and dry collecting means as the apparatus shown in FIG.
In the droplet discharge means 2, the raw material container 13 for storing the toner composition liquid 14 and the toner composition liquid 14 stored in the raw material container 13 are supplied to the droplet discharge unit 2 through the liquid supply pipe 16. The liquid supply pipe 16 is provided with a pressure measuring device P1 and the dry collecting means 60 is provided with a pressure measuring device P2. The pressure of the liquid feeding to the droplet discharge means 2 and the pressure in the dry collecting unit are the pressure gauge P1, Managed by P2. In the chamber 61, a descending airflow (conveyance airflow 101) formed from the conveyance airflow inlet 64 is formed. The droplets 21 discharged from the droplet discharge means 2 are transported downward not only by gravity but also by the transport airflow 101 and are collected by the particulate collection means 62.
The size and conditions of each component constituting the apparatus shown in FIGS.

-Toner collection part-
The chamber 61 has an inner diameter of φ400 mm and a height of 2000 mm, and is vertically fixed. The upper end and the lower end are narrowed, the diameter of the carrier airflow inlet is φ50 mm, and the diameter of the carrier airflow outlet is φ50 mm. is there. The droplet discharge means 2 is disposed at the center of the chamber 61 at a height of 300 mm from the upper end in the chamber 61. The carrier airflow was 10.0 m / s, 40 ° C., and atmospheric pressure air.

-Liquid column resonance droplet discharge unit-
The length L between both ends in the longitudinal direction of the liquid column resonance liquid chamber 18 is 1.85 [mm], N = 2 resonance mode, and the first to fourth discharge holes are N = 2 mode pressure standing. The one in which four discharge holes are arranged at the position of the wave belly was used. The discharge unit used was an accumulation of 400 liquid column resonance chambers.
The drive signal generation source was a NF company function generator WF 1973, which was connected to the vibration generation means with a polyethylene-coated lead wire. The driving frequency at this time is 340 [kHz] according to the liquid resonance frequency. A sine waveform voltage signal having a peak value of 9.0 V was input.
In addition, the temperature of the liquid column resonance liquid chamber was adjusted so that the temperature was 40 ° C., which was the same as the dry air flow.

Measurement of dissolved oxygen amount of toner composition liquid in saturated dissolved state Maintain the toner composition liquid at 40 ° C. and bubble air for 10 minutes at 40 ° C./1 atm. Then, the dissolved oxygen concentration in the spray solution was measured using a dissolved oxygen measuring device (DO measuring device B506 for organic solvents manufactured by Iijima Electronics Co., Ltd.). The amount of dissolved oxygen was 6.2 mg / L.

Production of flexible container Two polyethylene and nylon two-layer films were sandwiched with a polyethylene pipe attachment port and heat-welded to create a flexible container. When the internal volume was measured, it was 1000 cc. This flexible container was set in the pressure container 26.

[Example 1]
Toner was manufactured using the toner manufacturing apparatus 1 having the configuration shown in FIG.
The toner composition liquid was degassed under reduced pressure, and 900 cc was filled into a flexible container. The amount of dissolved oxygen in the filled toner composition liquid was measured and found to be 2.9 mg / L. The height of the center of the flexible container was fixed to be 25 cm lower than the position of the discharge hole of the liquid column resonance chamber, the pressure release valve 30 was opened, and the inside of the pressure container 26 was brought to atmospheric pressure.
A spray test was carried out in the fine particle production apparatus shown in FIG. All nozzles were observed and the number of ejection holes ejected during the 30 minute drive was monitored. As a result, it was confirmed that 1,590 of the total 1,600 ejection holes continued to be ejected stably until one hour later.
The toner composition liquid in the flexible container was 107 cc. The amount of dissolved oxygen in the toner composition liquid was measured and found to be 2.9 mg / L.

[Example 2]
Toner was manufactured using the toner manufacturing apparatus 1 having the configuration shown in FIG.
The toner composition liquid was degassed under reduced pressure while applying ultrasonic waves, and 500 cc was filled into a flexible container. The amount of dissolved oxygen in the filled toner composition was measured and found to be 1.8 mg / L. The height of the center of the flexible container was fixed to be 25 cm lower than the position of the discharge hole of the liquid column resonance chamber, the pressure release valve 30 was opened, and the inside of the pressure container 26 was brought to atmospheric pressure.
A spray test was carried out in the fine particle production apparatus shown in FIG. All nozzles were observed and the number of ejection holes ejected during a 120 minute drive was monitored. As a result, it was confirmed that 1,588 of the total 1,600 ejection holes continued to be ejected stably until 1 hour later.
The toner composition liquid in the flexible container was replenished from the resin composition liquid replenishment path 28 with the toner composition liquid degassed under reduced pressure while applying ultrasonic waves so that the capacity was 300 to 700 cc. The amount of dissolved oxygen in the toner composition liquid in the flexible container after 120 minutes was measured and found to be 1.9 mg / L.

[Example 3]
Toner was manufactured using the toner manufacturing apparatus 1 having the configuration shown in FIG.
The toner composition liquid was degassed under reduced pressure while applying ultrasonic waves, and 500 cc was filled into a flexible container. The amount of dissolved oxygen in the filled toner composition was measured and found to be 1.7 mg / L. The height of the center of the flexible container was fixed to be 25 cm lower than the position of the discharge hole of the liquid column resonance chamber. The pressure release valve 30 was closed, and the pressure vessel 26 was depressurized by the pressure adjusting air pump 26 so that the pressure at P1 was 2-3 KPa lower than the pressure at P2.
A spray test was carried out in the fine particle production apparatus shown in FIG. All nozzles were observed and the number of ejection holes ejected during a 120 minute drive was monitored. As a result, it was confirmed that 1,582 out of the total 1,600 discharge holes continued to be stably discharged until one hour later.
The toner composition liquid in the flexible container was replenished from the resin composition liquid replenishment path 28 with the toner composition liquid degassed under reduced pressure while applying ultrasonic waves so that the capacity was 300 to 700 cc. The amount of dissolved oxygen in the toner composition liquid in the flexible container after 120 minutes was measured and found to be 1.6 mg / L.

[Comparative Example 1]
Toner was manufactured using the toner manufacturing apparatus 1 having the configuration shown in FIG.
The raw material container 13 was filled with 900 cc without degassing the toner composition liquid. The amount of dissolved oxygen in the filled toner composition liquid was measured and found to be 5.4 mg / L. The height of the liquid surface of the raw material container 13 was adjusted to be a position 25 cm lower than the position of the discharge hole in the liquid column resonance chamber. The pressure in the raw material container is atmospheric pressure.
A spray test was carried out in the fine particle production apparatus shown in FIG. All nozzles were observed and the number of ejection holes ejected during the 30 minute drive was monitored. As a result, it was confirmed that 897 out of the total 1,600 discharge holes were stably discharged until after 1 hour.
The toner composition liquid in the raw material container was 256 cc. The amount of dissolved oxygen in the toner composition liquid was measured and found to be 5.6 mg / L.

[Comparative Example 2]
Toner was manufactured using the toner manufacturing apparatus 1 having the configuration shown in FIG.
The toner composition liquid was degassed under a low pressure, and 900 cc was filled into a flexible container. The amount of dissolved oxygen in the filled toner composition was measured and found to be 3.9 mg / L. The height of the center of the flexible container was fixed to be 25 cm lower than the position of the discharge hole of the liquid column resonance chamber, the pressure release valve 30 was opened, and the inside of the pressure container 26 was brought to atmospheric pressure.
A spray test was carried out in the fine particle production apparatus shown in FIG. All nozzles were observed and the number of ejection holes ejected during the 30 minute drive was monitored. As a result, it was confirmed that 1,106 of the total 1,600 ejection holes continued to be ejected stably until one hour later.
The toner composition liquid in the flexible container was 188 cc. The amount of dissolved oxygen in the toner composition liquid was measured and found to be 3.9 mg / L.

[Comparative Example 3]
Toner was manufactured using the toner manufacturing apparatus 1 having the configuration shown in FIG.
The toner composition liquid was degassed under reduced pressure while applying ultrasonic waves, and the raw material container 13 was filled with 900 cc. The amount of dissolved oxygen in the filled toner composition liquid was measured and found to be 2.1 mg / L. The height of the liquid surface of the raw material container 13 was adjusted to be a position 25 cm lower than the position of the discharge hole in the liquid column resonance chamber. The pressure in the raw material container is atmospheric pressure.
A spray test was carried out in the fine particle production apparatus shown in FIG. All nozzles were observed and the number of ejection holes ejected during the 30 minute drive was monitored. As a result, it was confirmed that 1,159 of the total 1,600 ejection holes continued to be ejected stably until after 1 hour.
The toner composition liquid in the raw material container was 156 cc. The amount of dissolved oxygen in the toner composition liquid was measured and found to be 4.8 mg / L.

  As described above, it is shown that, by degassing the resin composition liquid and filling the flexible container, the number of non-ejection ejection holes can be drastically reduced and the ejection can be maintained extremely stably.

1: Fine particle production apparatus 2: Droplet discharge unit 6: Fine particle composition liquid supply port 7: Fine particle composition liquid flow path 8: Fine particle composition liquid discharge port 9: Elastic plate 10: Liquid column resonance Droplet discharge unit 11: Liquid column resonance Droplet discharge means 12: Air flow passage 13: Raw material container 14: Fine particle composition liquid 16: Liquid supply pipe 17: Liquid common supply path 18: Liquid column resonance liquid chamber 19: Discharge hole 20: Vibration generating means 21: Droplet 24 : Nozzle angle 25: flexible container 26: pressure container 27: pressure adjusting air pump 28: resin composition liquid supply path 29: resin composition liquid supply valve 30: pressure release valve 60: dry collection means 61: chamber 62: particulate collection Means 63: Particulate reservoir 64: Conveyance airflow inlet 65: Conveyance airflow outlet 101: Conveyance airflow P1: Liquid pressure gauge P2: In-chamber pressure gauge

Japanese Patent No. 3786034 Japanese Patent No. 3786035 JP-A-57-201248 JP 2006-293320 A

Claims (6)

A fine particle composition liquid obtained by dissolving or dispersing a composition containing at least a resin in a solvent is supplied to a droplet discharge unit that continuously discharges from one or more discharge holes into droplets, and the fine particle composition liquid is liquid In a method for producing fine particles, comprising: a droplet forming step for forming droplets; and a droplet solidifying step for solidifying the droplets by drying a solvent of the droplet-formed fine particle composition liquid.
The droplet formation step forms a standing wave by liquid column resonance by applying high frequency vibration to the fine particle composition liquid in the liquid column resonance liquid chamber in which one or more discharge holes are formed, and the standing wave of the standing wave A step of discharging the fine particle composition liquid into droplets from the discharge holes arranged in a region where the pressure fluctuation has a sufficient amplitude to discharge the liquid;
A method for producing fine particles, which satisfies the following requirements A and B.
A. The resin composition liquid is filled into a flexible container so that gas does not enter, and the resin composition liquid is supplied from the flexible container to the droplet discharge unit.
B. The amount of dissolved oxygen in the resin composition liquid in the flexible container is ½ or less of the amount of dissolved oxygen when the resin composition liquid is saturated with air. The fine particle manufacturing method according to claim 1 , wherein the liquid column resonance liquid chamber has two or more discharge holes. 3. The fine particle production according to claim 1, wherein a new fine particle composition liquid that has been degassed is added to the flexible container while the fine particle composition liquid is being supplied from the flexible container to the droplet discharge unit. Method. Put the flexible container in the pressure vessel, by adjusting the pressure in the pressure vessel, it claims 1-3, characterized by adjusting the supply pressure of the particulate composition liquid to the droplet discharge unit The method for producing fine particles according to [1]. Fine particles according to any one of claims 1-4, characterized by adjusting the supply pressure of the resin composition liquid to the droplet discharge unit by changing the vertical position of the flexible container with respect to the droplet discharge units Production method. A fine particle production apparatus for carrying out the production method according to claim 1,
A flexible container containing a fine particle composition solution obtained by dissolving or dispersing a composition containing at least a resin in a solvent;
A droplet discharge unit that continuously discharges the fine particle composition liquid from one or more discharge holes into droplets;
Means for supplying the fine particle composition liquid in the flexible container to the droplet discharge unit;
Droplet solidifying means for drying the solvent of the fine particle composition liquid into droplets to solidify the droplets, and
The droplet discharge unit forms a standing wave by liquid column resonance by applying high-frequency vibration to the fine particle composition liquid in the liquid column resonance liquid chamber in which one or more discharge holes are formed, and the standing wave of the standing wave A unit that discharges the fine particle composition liquid into droplets from the discharge holes arranged in a region where the pressure fluctuation has an amplitude large enough to discharge the liquid;
An apparatus for producing fine particles, wherein the amount of dissolved oxygen in the resin composition liquid in the flexible container is set to ½ or less of the amount of dissolved oxygen when the resin composition liquid is saturated with air.

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