JP2013063408A - Fine particle manufacturing method and fine particle manufacturing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fine particle manufacturing method by a jet granulation method for maintaining high stability of discharge of a liquid containing a fine particle component, and obtaining fine particles that have narrow particle size distribution, and to provide a fine particle manufacturing apparatus.SOLUTION: The fine particle manufacturing apparatus includes: a droplet discharge means 2 that has a vibration generating means for imparting the vibration to a liquid column resonance liquid chamber, into which a toner component liquid 14 that becomes toner when its droplets solidify is introduced, and the toner component liquid 14 in the liquid column resonance liquid chamber; and a drying collection unit 60 that solidifies the droplets 21 discharged from the droplet discharge means 2. The droplet discharge means 2 has: a droplet discharge operation mode to impart the vibration to the toner component liquid 14 in the liquid column resonance liquid chamber by the vibration generating means to form a standing wave by the liquid column resonance, and continuously discharge the toner component liquid 14 as droplets from discharge holes formed in a region that is an antinode of the standing wave; and a minute driving operational mode to vibrate the liquid surface of the toner component liquid 14 in the discharge hole by the vibration generating means prior to the droplet discharge operation.

Description

  The present invention relates to a fine particle production method and a fine particle production apparatus using a jet granulation method.

  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.

  In general, the toner obtained by the polymerization method is easier to obtain a smaller particle size, has a narrow particle size distribution, and has a nearly spherical shape compared to the toner obtained by the pulverization method. The image in is advantageous in 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 obtained by dissolving or dispersing a toner raw material component 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, see 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.

  To deal with such problems, the toner production method by jet granulation described in Patent Document 4 does not require a large amount of cleaning liquid, repeated separation of solvent and particles, saves energy, and has a narrow particle size distribution. Can be manufactured.

  However, in the manufacturing method described in Patent Document 4, it has been confirmed that the number of normally ejected ejection holes decreases with the ejection time, thereby reducing the toner production efficiency. There is a need to reduce the above-mentioned problems associated with ejection and improve toner production efficiency.

  The present invention has been made in view of the above-described problems in the prior art, and in the method for producing fine particles by the injection granulation method, the injection (discharge) of the fine particle component-containing liquid is maintained in a highly stable state and is narrow. An object of the present invention is to provide a fine particle production method and a fine particle production apparatus for obtaining fine particles having a particle size distribution.

  The present invention provided in order to solve the above-mentioned problems is to form a standing wave by liquid column resonance by applying vibration to a liquid containing a fine particle component that is introduced into a liquid column resonance liquid chamber and becomes a fine particle when a droplet is solidified. A droplet discharge step of continuously discharging the liquid containing the fine particle component from the discharge hole disposed in the antinode of the standing wave in the liquid column resonance liquid chamber to form a droplet; A fine driving step of vibrating a liquid surface of the fine particle component-containing liquid in the discharge hole before the droplet discharging step.

  In addition, the present invention provided to solve the above-described problems is that the liquid column resonance liquid chamber into which the liquid containing the fine particle component that becomes fine particles when the liquid droplets are solidified and the liquid containing the fine particle component in the liquid column resonance liquid chamber are vibrated. An apparatus for producing fine particles comprising a droplet discharge means having a vibration generating means for applying, wherein the droplet discharge means applies a vibration to the liquid containing the fine particle component in the liquid column resonance liquid chamber by the vibration generation means. A droplet that forms a standing wave by column resonance and continuously discharges the liquid containing the fine particle component as a droplet from the discharge hole formed in the antinode of the standing wave in the liquid column resonance liquid chamber An apparatus for producing fine particles, comprising: a discharge operation mode; and a fine drive operation mode in which the vibration generating means vibrates the liquid surface of the fine particle component-containing liquid in the discharge hole before the droplet discharge operation. .

  According to the fine particle production method (or fine particle production apparatus) of the present invention, in the fine particle production method by the jet granulation method, the fine particles in the discharge holes are provided before the droplet discharge step (droplet discharge operation) for producing the fine particles. Since the fine drive process (fine drive operation) is performed to vibrate the liquid surface of the component-containing liquid, the number of discharge holes that do not discharge due to clogging is reduced, and droplets can be discharged from all the discharge holes as much as possible. Thus, since the droplet discharge step (droplet discharge operation) is performed, stable and efficient discharge can be maintained, and a toner having a narrow particle size distribution can be obtained.

It is sectional drawing which shows the structure of a liquid column resonance droplet discharge means. It is sectional drawing which shows the structure of a liquid column resonance droplet formation unit. It is sectional drawing which shows the structural example of a discharge hole. 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 discharge means. It is sectional drawing which shows another structure of a liquid column resonance droplet discharge means. 1 is a schematic view of a toner manufacturing apparatus according to the present invention.

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

A configuration example of the present invention will be described below with reference to FIGS.
The toner production means of the present invention is a fine particle production apparatus that produces toner as fine particles, and is divided into a droplet discharge means and a droplet solidification collecting means. Each is explained below.

[Droplet discharge means]
The droplet discharge means used in the present invention has a narrow particle size distribution of discharged droplets and vibrates the liquid in the liquid column resonance liquid chamber in which a plurality of discharge holes are formed in order to ensure toner productivity. It is preferable to use droplet-formed liquid column resonance that is applied to form a standing wave by liquid column resonance and discharges liquid from the discharge hole formed in the region that becomes the antinode of the standing wave.

(Liquid column resonance droplet discharge means)
FIG. 1 shows a liquid column resonance droplet discharge means 11.
As shown in FIG. 1, the liquid column resonance droplet discharge means 11 includes a liquid common supply path 17 and a liquid column resonance liquid chamber 18. Here, the liquid column resonance liquid chamber 18 communicates with the liquid common supply path 17 provided on one wall surface 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 droplet discharge means (liquid column resonance droplet discharge means 11) is a “particulate component-containing liquid”. The fine particle component-containing liquid may contain any fine particle component to be obtained and can be discharged from the droplet discharge means. For example, the fine particle component is dissolved or dispersed in a solvent, or does not contain a solvent. In a state where the fine particle components are melted. Hereinafter, for the purpose of describing the case of manufacturing the toner, this will be described as “toner component liquid”.

  The toner component 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. A pressure distribution is formed in the liquid column resonance liquid chamber 18 filled with the toner component liquid 14 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 toner component 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 (storage means).

  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 liquid column resonance droplet forming unit 10 in order to dramatically improve productivity. The range is not limited, but one liquid column resonance droplet forming unit provided with 100 to 2000 liquid column resonance liquid chambers 18 can achieve both operability and productivity, and is most preferable. 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 the common liquid supply path 17 communicates with a plurality of liquid column resonance liquid chambers 18. .

Further, the vibration generating means 20 in the liquid column resonant 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 18 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 controlled individually for each liquid column resonance liquid chamber 18. Further, the block-shaped vibrating member made of one material is partially cut in accordance with the arrangement of the liquid column resonance liquid chambers 18 so that each liquid column resonance liquid chamber 18 can be individually controlled via the elastic plate 9. Is 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. When the particle diameter is larger than 40 [μm], the droplet diameter is large, and when this is dried and solidified to obtain a desired toner particle diameter of 3 to 6 μm, the toner composition is diluted with an organic solvent into a very dilute liquid. 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.

In FIG. 3, the cross-sectional shape which the discharge hole 19 can take is shown.
The discharge hole 19 shown in FIG. 3A has such a shape that the opening diameter becomes narrow while having a round shape from the liquid contact surface of the discharge hole 19 toward the discharge hole, and when the thin film 41 vibrates. In addition, since the pressure applied to the liquid is maximized in the vicinity of the outlet of the discharge hole 19, it is the most preferable shape for stabilizing discharge.

The discharge hole 19 shown in FIG. 3B has such a shape that the opening diameter becomes narrower from the liquid contact surface of the discharge hole 19 toward the discharge hole, and the nozzle angle 44 is It can be changed as appropriate. As in the case of FIG. 3A, 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, but the range is preferably 60 to 90 °. If it is less than 60 °, it is difficult to apply pressure to the liquid and it is difficult to process the thin film 41, which is not preferable. When the nozzle angle 44 is 90 °, it corresponds to the discharge hole 19 shown in FIG. 3C, but when it exceeds 90 °, no pressure is applied to the outlet of the discharge hole 19 and the droplet discharge is very unstable. Therefore, 90 ° is the maximum value.
The discharge hole 19 shown in FIG. 3 (d) has a shape combining FIGS. 3 (a) and 3 (b). In this way, the shape may be changed step by step.

Next, the mechanism of droplet formation by the droplet formation unit (liquid column resonance droplet formation unit 10) 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 driving frequency given from the means 20 to the toner component liquid that is a medium is f, the wavelength λ at which the liquid resonance occurs is
λ = c / f (Formula 1)
Are in a relationship.

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 as high as the communication port height h2 (= about 40 [μm]), and the both ends are assumed to be equivalent to the closed fixed end. In the edge case, resonance is most efficiently formed 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 formula 2 is also established in the case of both open ends where both ends are completely open.
Similarly, when one side is equivalent to an open end with 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 obtained from Equation 1 and Equation 2.
f = N × c / (4L) (Formula 3)
It is guided. 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 the velocity and pressure fluctuation (resonance mode) when N = 1, 2, and 3. Also, FIG. 5 shows the velocity and pressure fluctuation constant when N = 4 and 5. The shape of the standing wave (resonance mode) is shown.
Originally a sparse wave (longitudinal wave), it is generally expressed as shown in FIGS. 4 and 5, where 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 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. .

  When the length between the longitudinal ends of the liquid column resonance liquid chamber 18 is L, the wavelength at which the liquid resonates is λ, and the standing wave is generated most efficiently when the integer N is 1 to 5. To do. 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 19 and the opening on 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 depending on the number of discharge holes and the opening position of the discharge holes 19 The standing wave pattern fluctuates and a resonance frequency appears at a position deviated from the position obtained from Equation 3. However, a stable ejection condition 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 18 is 1.85 [mm], wall surfaces are present at both ends, and the both ends are completely fixed. When the equivalent resonance mode of N = 2 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 18 is 1.85 [mm], and there are wall surfaces at both ends using the same conditions as described above. Then, when N = 4 resonance mode equivalent to the fixed ends on both sides is used, the most efficient resonance frequency is derived as 648 kHz from the equation (2), and even in the liquid column resonance liquid chamber 18 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 explained as an acoustically soft wall due to the fact that both ends are equivalent to the closed end state or the influence of the opening of the discharge holes 19. 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 18 as shown in FIG. 4B and FIG. 5A is the resonance mode at both fixed ends, and the discharge hole 19 side is open. This is a preferable configuration because all the resonance modes of the one-side open end that are considered to be used can be used.

  Further, the numerical aperture of the discharge holes 19, the opening arrangement position, and the cross-sectional shape of the discharge holes 19 are factors that determine the drive frequency, and the drive frequency can be appropriately determined according to this. For example, when the number of the discharge holes 19 is increased, the restriction at the tip of the liquid column resonance liquid chamber 18 which has been the fixed end gradually becomes loose, a resonance standing wave substantially close to the opening end is generated, and the drive frequency increases. In addition, the opening position of the discharge hole 19 that is closest to the liquid supply path is a starting point, and the discharge hole 19 is loosely constrained. The cross-sectional shape of the discharge hole 19 is round or the volume of the discharge hole varies depending on the thickness of the frame. The actual standing wave has a short wavelength and is higher than the driving frequency. When a voltage is applied to the vibration generating means 20 at the drive frequency determined in this way, the vibration generating means 20 is deformed and generates a resonant standing wave 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 18 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. Then, the vibration generating means 20 is vibrated using a drive waveform whose main component is the drive frequency f in the range determined by the following formulas 4 and 5, and liquid droplet resonance is induced to eject droplets from the ejection holes 19. It is possible.

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 18 to the distance Le to the discharge hole 19 closest to the end on the liquid supply side is Le / L> 0.6. preferable.

  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 18 in the droplet discharge head in the liquid column resonance droplet forming unit will be described with reference to FIG. In the figure, the solid line in the liquid column resonance liquid chamber 18 indicates the speed 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. Is plotted, and the direction from the liquid common supply path 17 side to the liquid column resonance liquid chamber 18 is defined as +, and the opposite direction is defined as-. In addition, a dotted line written in the liquid column resonance liquid chamber 18 plots pressure values at arbitrary measurement positions 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 pressure distribution is shown, and positive pressure is + and negative pressure is-with respect to atmospheric pressure. 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, as described above, the liquid common supply path 17 side is open, 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). Since the height of the frame serving as the fixed end (height h1 shown in FIG. 1) is about twice or more than that of the liquid column resonance liquid chamber 18, the approximate condition is that the liquid column resonance liquid chamber 18 is substantially fixed on both sides. The change of each of the velocity distribution and pressure distribution in 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. Thus, a standing wave due to liquid column resonance is generated in the liquid column resonance liquid chamber 18 by high frequency driving of the vibration generating means 20, and the standing wave due to liquid column resonance at a position where the pressure fluctuates most greatly is generated. Since the discharge hole 19 is disposed in the droplet discharge region corresponding to the antinode, the droplet 21 is continuously discharged from the discharge hole 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 19 are provided. As a result of disposing the discharge hole at the antinode of the N = 2 mode pressure standing wave and performing the driving frequency with a sine wave of 330 [kHz], the droplets with very uniform diameter and almost uniform speed Discharging was realized. Further, in the range of the drive frequency 290 [kHz] to 395 [kHz], the discharge speed from each discharge hole 19 becomes uniform in the first to fourth discharge holes 19 near the drive frequency of 330 [kHz] And it was the maximum discharge speed. That is, in 330 [kHz] which is the second mode of the liquid column resonance frequency, uniform discharge is realized at the antinode position of the liquid column resonance standing wave. Further, the liquid crystal resonance of the liquid column resonance in which no droplet is ejected between the droplet ejection speed peak at 130 [kHz] which is the first mode and the droplet ejection speed peak at 330 [kHz] which is the second mode. The characteristic frequency characteristic of the liquid column resonance standing wave is generated in the liquid column resonance liquid chamber.

FIG. 7 shows another configuration of the liquid column resonance droplet discharge means.
Compared with the configuration of FIG. 1, the only difference is that the direction of the first airflow in the airflow passage 12 flowing in the vicinity of the droplet discharge means is the lateral direction (left direction in the figure) with respect to the droplet discharge direction. Is the same as the configuration of FIG.

[Droplet solidification means]
The toner of the present invention can be obtained by solidifying and then collecting the droplets of the toner component liquid 14 discharged into the gas from the droplet discharge means described above.
In order to solidify the toner component liquid 14, depending on the properties of the toner component, the way of thinking is different, but basically any means can be used as long as the toner component liquid 14 can be in a solid state. For example, if the toner component liquid 14 is obtained by dissolving or dispersing a solid raw material in a volatile solvent, it can be achieved by drying the droplets in the conveying airflow after the droplets are jetted, 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. Even if it does not follow the said example, you may achieve by application of a temperature change, a chemical reaction, etc.

[Solidifying 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.

[Configuration example of toner production apparatus]
FIG. 8 is a cross-sectional view showing a configuration example of an apparatus for carrying out the toner manufacturing method of the present invention.
The toner manufacturing apparatus 1 mainly includes a droplet discharge means 2 and a dry collection unit 60.

  Here, the dry collection unit 60 includes a chamber 61 which is a droplet solidification means having a droplet discharge means 2 connected to the upper part thereof, a solidified particle collection means 62 connected to the lower part of the chamber 61, and a solidified particle. A toner reservoir 63 connected to the collecting means 62.

The droplet discharge means 2 is, for example, the liquid column resonance droplet discharge means 11 described above.
The droplet discharge means 2 is connected to a liquid supply means 3 for supplying the toner component liquid 14 from the storage means for storing the toner component liquid 14 to the droplet discharge means 2 in accordance with the discharge amount of the droplets. Yes.

  The liquid supply means 3 includes a raw material storage container 13 that stores the toner component liquid 14, a liquid supply pipe 16 that supplies the liquid droplet discharge means 2 through the toner component liquid 14 stored in the raw material storage container 13, and a liquid supply pipe 16 includes a liquid circulation pump 15 that pumps the toner component liquid 14 in the liquid medium 16 and a liquid return pipe 22 that returns the toner component liquid 14 from the droplet discharge means 2 to the raw material container 13. It can be supplied to the droplet discharge means 2 at any time.

  The liquid supply pipe 16 is provided with a pressure measuring device (pressure gauge) P1 and the chamber 61 of the dry collection unit 60 is provided with a pressure measurement device (pressure gauge) P2, and the liquid supply pressure to the droplet discharge means 2 and the dry collection are collected. The pressure in the unit 60 is managed by pressure gauges P1 and P2. At this time, if P1> P2, the toner component liquid 14 may ooze out from the discharge hole 19, and if P1 <P2, gas may enter the droplet discharge means 2 and discharge may stop. Therefore, it is desirable that P1≈P2.

  In the chamber 61, a carrier airflow 101 is formed which is a descending airflow introduced from a carrier airflow inlet 64 at the upper part thereof. The droplets 21 discharged from the droplet discharge means 2 are transported downward not only by gravity but also by the transport airflow 101, dried to become solidified particles, and collected by the solidified particle collecting means 62, The toner is stored in the toner storage unit 63.

(About transport airflow)
When droplets ejected from the droplet discharge means 2 come into contact with each other before drying, the droplets 21 coalesce into 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 liquid droplets from coming into contact with each other while preventing the coalescence. The solidified particles are conveyed to the collecting means 62.

For example, as shown in FIG. 1, a part of the transport airflow 101 is disposed in the vicinity of the droplet discharge means in the same direction as the droplet discharge direction as a first airflow, so that the droplet velocity immediately after the droplet discharge. Decline can be prevented and coalescence can be prevented. Alternatively, as shown in FIG. 8, the direction may be transverse to the droplet discharge 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. 8, 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 holes. .
Further, after the coalescence is prevented by the first air stream as described above, the solidified particles may be carried to the solidified particle collecting means 62 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, a means for changing the airflow state of the carrier airflow 101 in the chamber 61 may be taken. The carrier airflow 101 may be used not only to prevent the adhesion of the droplets 21 but also to prevent the droplets 21 from adhering to the chamber 61.

(Secondary drying means)
If the amount of residual solvent contained in the toner particles obtained by the dry collection unit 60 shown in FIG. 8 is large, secondary drying is performed by secondary drying means (not shown) as necessary to reduce this. Is done. 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.

By the way, in the droplet discharge means 2 (liquid column resonance droplet discharge means), uniform droplets are discharged from the discharge holes 19 at a constant cycle. However, the discharge holes 19 depend on the solid content and the dissolved component in the toner component liquid 14. In some cases, the discharge becomes unstable due to the clogging of the liquid column or the mixing of bubbles into the liquid column resonance liquid chamber 18, and the discharge from the discharge hole 19 may stop.
Further, the clogging of the discharge holes 19 is caused by decreasing the diameter of the discharge holes 19 to make the discharged droplet diameter non-uniform, or by varying the discharge speed and the discharge direction, and before and after the discharged droplets and other surrounding discharge holes. The possibility of merging with the droplets discharged from is increased. For this reason, the resulting toner has a wide particle size distribution.
Therefore, in the present invention, the way of driving the droplet discharge means 2 (liquid column resonance droplet discharge means) is devised to improve it.

That is, as the operation mode of the droplet discharge means 2, the vibration generating means 20 applies vibration to the toner component liquid in the liquid column resonance liquid chamber 18 to form a standing wave due to liquid column resonance. A droplet ejection operation mode in which the toner component liquid is continuously ejected as droplets from the ejection holes 19 formed in the stomach region, and before the droplet ejection operation, the vibration generating means 20 A control means (not shown) for controlling the driving of each part constituting the toner manufacturing apparatus 1 has a fine driving operation mode for vibrating the liquid surface of the toner component liquid. By controlling appropriately, it is possible to maintain the highly stable ejection of the droplet ejection means 2.
Specifically, the control is performed as follows.

(Control of toner production apparatus 1)
In the toner manufacturing apparatus 1, the control unit performs the following control with respect to toner manufacturing.
(S11) When the toner component liquid discharge is stopped due to maintenance or the like, and before the droplet discharge operation for toner production, the control unit controls the operation of the droplet discharge unit 2 in the fine drive operation mode. Specifically, the toner component liquid is supplied into the liquid column resonance liquid chamber 18, and the droplets of the toner component liquid are not discharged from the ejection holes 19 to the toner component liquid in the liquid column resonance liquid chamber 18 by the vibration generating means 20. The vibration of the degree is continuously applied for a certain period of time to control the operation of vibrating the liquid surface of the toner component liquid in the discharge hole 19.
Thereby, clogging of the discharge hole 19 is improved, and bubbles mixed in the liquid column resonance liquid chamber 18 are also removed.
At this time, the drive signal input to the vibration generating means 20 has the same frequency as the drive signal input to the vibration generating means 20 in the droplet discharge operation mode, and the vibration amplitude is low. Alternatively, it is preferable that the frequency is different from the drive signal (frequency signal to be resonated (resonated) in the liquid column resonance liquid chamber 18) input to the vibration generating means in the droplet discharge operation mode.
(S12) Next, the control unit controls the operation of the droplet discharge unit 2 in the droplet discharge operation mode. At this time, the drive signal input to the vibration generating unit 20 is a signal having a frequency to be resonated (resonated) in the liquid column resonance liquid chamber 18, whereby the vibration generation unit 20 causes the toner component in the liquid column resonance liquid chamber 18 to be resonated. Operation control is performed such that a vibration is applied to the liquid to form a standing wave by liquid column resonance, and the toner component liquid is continuously discharged as droplets from the discharge hole 19 formed in the antinode of the standing wave. Do. At this time, each part of the toner manufacturing apparatus 1 is also in operation. For example, the liquid supply unit 3 supplies the toner component liquid from the raw material container 13 to the droplet discharge unit 2 according to the discharge amount of the droplets 21. To do.

  As described above, the clogging of the discharge holes of the droplet discharge means 2 is improved by the fine drive operation mode before the droplet discharge operation, and the droplets can be discharged from all the discharge holes. Thus, since the droplet discharge operation is performed, stable and efficient discharge can be maintained, and a toner having a narrow particle size distribution can be obtained.

(toner)
The toner of the present invention contains at least a resin, a colorant, and a wax, and optionally contains 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, or may be free from a solvent as long as it is a liquid under the conditions of ejection, and a part or all of the toner component is melted. In a liquid state.
As the toner material, if the toner component liquid 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 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.

  As the magnetic material that can be used in the present invention, known magnetic materials conventionally used for electrophotographic toners can be used. For example, (1) magnetic iron oxide such as magnetite, maghemite, ferrite, and iron oxide containing 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 examples of commercially available 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.

〔Additive〕
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 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].

  Next, specific examples in this embodiment will be described. In addition, this invention is not limited to the following Example at all.

First, the formulation of the toner component liquid (dissolved or dispersed) used in this example is shown.
-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 component 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 weight of a polyester resin as a binder resin, 30 parts by weight of the colorant dispersion, 30 parts by weight of the wax dispersion, 840 parts by weight 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.

-Toner production equipment-
Using the toner manufacturing apparatus 1 having the configuration shown in FIG. 8, toner was manufactured by a liquid column resonance droplet discharge means.
The size and conditions of each component are described below.
First, as the droplet discharge means 2, the above-described liquid column resonance droplet discharge means 11 (FIG. 1) was used.
Here, the length L between both ends in the longitudinal direction of the liquid column resonance liquid chamber 18 is 1.85 [mm] and N = 2, and the first to fourth discharge holes 19 are N = 2. The one in which the discharge hole is arranged at the antinode of the mode pressure standing wave 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. Moreover, the vibration generating means 20 was a laminate of lead zirconate titanate (PZT) piezoelectric thin films.
In this embodiment, 384 liquid column resonance liquid chambers 18 having the first to fourth discharge holes 19 are arranged in the droplet discharge head, and a total of 1536 discharge holes 19 are used. It was.

  The chamber 61 of the toner collecting portion is vertically fixed with a cylindrical shape having an inner diameter of 400 [mm] and a height of 2000 [mm], and 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. 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 101 was 10.0 m / s and nitrogen at 40 ° C.

Example 1
Using the toner manufacturing apparatus 1 described above, the toner was manufactured by controlling the droplet discharge means 2 in the following procedure.
(S21) The toner component liquid is supplied into the liquid column resonance liquid chamber 18 and a sine wave drive signal having a voltage of 2 V and a frequency of 330 kHz is input to the vibration generating means 20 before the start of the droplet discharge operation (when the discharge is stopped). Then, the liquid surface of the toner component liquid in the discharge hole 19 was vibrated continuously for 30 seconds (fine drive operation control).
(S22) A sine wave drive signal (discharge signal) having a voltage of 7 V and a frequency of 330 kHz is input to the vibration generating means 20, and the toner component liquid is continuously discharged as droplets 21 from the discharge holes 19 for 10 minutes ( Droplet discharge control). At this time, the discharged droplets 21 were solidified in the chamber 61 and collected as toner by the solidified particle collecting means 62.

(Example 2)
In Example 1, the toner was manufactured by controlling the droplet discharge means 2 under the same conditions as in Example 1 except that the discharge time in Step S22 (Droplet discharge operation control) was 30 minutes.

(Example 3)
In Example 1, the voltage of the drive signal in step S21 (fine drive operation control) was set to 0.5 V, and other than that, the droplet discharge means 2 was controlled under the same conditions as in Example 1 to produce toner.

Example 4
In Example 2, the voltage of the drive signal in step S21 (fine drive operation control) was set to 0.5 V, and other than that, the droplet discharge means 2 was controlled under the same conditions as in Example 2 to produce toner.

(Example 5)
In Example 1, the voltage of the drive signal in step S21 (fine drive operation control) was set to 1 V, and other than that, the droplet discharge means 2 was controlled under the same conditions as in Example 1 to produce toner.

(Example 6)
In Example 2, the voltage of the drive signal in step S21 (fine drive operation control) was set to 1 V, and other than that, the droplet discharge means 2 was controlled under the same conditions as in Example 2 to produce toner.

(Example 7)
In Example 1, the voltage of the drive signal in step S21 (fine drive operation control) was set to 3 V, and the other components were controlled under the same conditions as in Example 1 to manufacture toner.

(Example 8)
In Example 2, the voltage of the drive signal in step S21 (fine drive operation control) was set to 3 V, and the other components were controlled under the same conditions as in Example 2 to manufacture toner.

Example 9
In Example 1, the frequency of the drive signal in step S21 (fine drive operation control) was set to 320 kHz, and other than that, the droplet discharge means 2 was controlled under the same conditions as in Example 1 to produce toner.

(Example 10)
In Example 2, the frequency of the drive signal in step S21 (fine drive operation control) was set to 320 kHz, and other than that, the droplet discharge means 2 was controlled under the same conditions as in Example 2 to produce toner.

(Example 11)
In Example 1, the frequency of the drive signal in Step S21 (fine drive operation control) was set to 340 kHz, and other than that, the droplet discharge means 2 was controlled under the same conditions as in Example 1 to produce toner.

(Example 12)
In Example 2, the frequency of the drive signal in step S21 (fine drive operation control) was set to 340 kHz, and other than that, the droplet discharge means 2 was controlled under the same conditions as in Example 2 to produce toner.

(Comparative Example 1)
In Example 1, the fine drive operation control in Step S21 was not performed, and the droplet ejection operation in Step S22 was controlled under the same conditions as in Example 1 except that the toner was manufactured.

(Comparative Example 2)
In Example 2, the fine drive operation control in Step S21 was not performed, and the droplet ejection operation in Step S22 was controlled under the same conditions as in Example 2 except that the toner was manufactured.

(Evaluation method)
In Examples 1 to 12 and Comparative Examples 1 and 2, the evaluation of the discharge level during the droplet discharge operation and the evaluation of the particle size of the obtained toner were performed as follows.

−Discharge level evaluation−
The discharge level evaluation was performed based on the ratio of the discharge holes that normally discharge with respect to all the discharge holes that received the discharge signal. Specifically, it is determined whether the discharge is normal from the enlarged image of the discharge holes taken with the camera at the start of discharge or immediately before the end of discharge (at the end of discharge), and the number of discharge holes that are normally discharged is directly counted and the ratio is calculated. Calculated. In the evaluation, 95% or more was evaluated as ◎, 85% or more, less than 95% as ◯, 75% or more, less than 85% as Δ, and less than 75% as x (Table 1).

-Particle size evaluation-
For particle size evaluation, the particle size of the toner was measured with a flow type particle image analyzer under the following measurement conditions to determine the average particle size distribution of the toner.
A measurement method using a flow particle image analyzer (Flow Particle Image Analyzer) will be described below. The measurement of toner, toner particles and external additives using a flow type particle image analyzer can be performed using, for example, a flow type particle image analyzer FPIA-3000 manufactured by Toa Medical Electronics Co., Ltd.
The measurement is performed by removing fine dust through a filter, and as a result, in ^10-3 water of 10 ⁻³ cm ³ of water having a measurement range (for example, an equivalent circle diameter of 0.60 μm or more and less than 159.21 μm) of 20 particles or less. Add a few drops of a nonionic surfactant (preferably Contaminone N manufactured by Wako Pure Chemical Industries, Ltd.), add 5 mg of a measurement sample, and under conditions of 20 kHz and 50 W / 10 cm ^{3 with} an ultrasonic dispersing device STM UH-50. Dispersion treatment is performed for 1 minute, and further, dispersion treatment is performed for a total of 5 minutes, and a sample dispersion liquid in which the particle concentration of the measurement sample is 4000 to 8000 particles / ⁻³ cm ³ (for particles in the diameter range corresponding to the measurement circle) Then, the particle size distribution (weight average particle diameter Dv, number average particle diameter Dn) of particles having an equivalent circle diameter of 0.60 μm or more and less than 159.21 μm is measured.
The sample dispersion liquid is passed through a flow path (expanded along the flow direction) of a flat and flat transparent flow cell (thickness: about 200 μm). In order to form an optical path that passes across the thickness of the flow cell, the strobe and the CCD camera are mounted on the flow cell so as to be opposite to each other. While the sample dispersion is flowing, strobe light is irradiated at 1/30 second intervals to obtain an image of the particles flowing through the flow cell, so that each particle has a certain range parallel to the flow cell. Photographed as a two-dimensional image. From the area of the two-dimensional image of each particle, the diameter of a circle having the same area is calculated as the equivalent circle diameter.
In the flow type particle image analyzer, the equivalent circle diameter of 1200 or more particles can be measured in about 1 minute, and the number based on the equivalent circle diameter distribution and the ratio of particles having the prescribed equivalent circle diameter (number) %) Can be measured. The results (frequency% and cumulative%) can be obtained by dividing the range of 0.06 to 400 μm into 226 channels (divided into 30 channels per octave). In actual measurement, particles are measured in the range where the equivalent circle diameter is 0.60 μm or more and less than 159.21 μm.

The particle size distribution can be compared by the ratio of the volume average particle diameter (Dv) and the number average particle diameter (Dn), and can be expressed by Dv / Dn. The smallest Dv / Dn value is 1.0, which indicates that all the particle sizes are the same. A larger Dv / Dn indicates a wider particle size distribution. A general pulverized toner has Dv / Dn = 1.15 to 1.25. The polymerized toner has a Dv / Dn of about 1.10 to 1.15.
Table 1 shows the evaluation criteria for particle size evaluation.

Table 2 shows the results of fine drive operation conditions, droplet discharge operation conditions, discharge level evaluation, and particle size evaluation in Examples 1 to 12 and Comparative Examples 1 and 2.
According to the fine particle manufacturing method that performs the fine driving step (fine driving operation mode) of the present invention, it is possible to improve the droplet discharge state and obtain toner having a narrow particle size distribution.

DESCRIPTION OF SYMBOLS 1 Toner manufacturing apparatus 2 Droplet discharge means 3 Liquid supply means 9 Elastic board 10 Liquid column resonance droplet formation unit 11 Liquid column resonance droplet discharge means 12 Airflow path 13 Raw material storage container 14 Toner component liquid 15 Liquid circulation pump 16 Liquid supply Pipe 17 Liquid common supply path 18 Liquid column resonance liquid chamber 19 Discharge hole 20 Vibration generating means 21 Liquid droplet 22 Liquid return pipe 41 Thin film 44 Nozzle angle 60 Drying collecting unit 61 Chamber 62 Solid particle collecting means (toner collecting means)
63 Toner reservoir 64 Transport airflow inlet 65 Transport airflow outlet 101 Transport 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 (8)

  When the liquid droplets solidified introduced into the liquid column resonance liquid chamber are vibrated, the liquid containing the fine particle component is vibrated to form a standing wave by liquid column resonance, and the standing wave is generated in the liquid column resonance liquid chamber. A droplet discharge step of continuously discharging the liquid containing the fine particle component from the discharge hole arranged in the region that becomes the antinode of the droplet to form a droplet, and before the droplet discharge step, the droplet in the discharge hole A fine driving step of vibrating a liquid surface of the fine particle component-containing liquid.   2. The fine particle production according to claim 1, wherein the vibration of the liquid surface of the discharge hole in the fine driving step has the same frequency as the vibration in the droplet discharge step and has a reduced vibration amplitude. Method.   The fine particle manufacturing method according to claim 1, wherein the frequency of vibration of the liquid surface of the discharge hole in the fine driving step is different from the frequency of vibration in the droplet discharge step. Fine particles provided with a liquid column resonance liquid chamber into which a liquid containing a fine particle component, which becomes fine particles when the droplet is solidified, and a droplet discharge means having vibration generation means for imparting vibration to the fine particle component containing liquid in the liquid column resonance liquid chamber Manufacturing equipment,
The droplet discharge means imparts vibration to the liquid containing the fine particle component in the liquid column resonance liquid chamber by the vibration generating means to form a standing wave by liquid column resonance, and the standing liquid is present in the liquid column resonance liquid chamber. A droplet discharge operation mode in which the fine particle component-containing liquid is continuously discharged as droplets from the discharge hole formed in a region where the wave becomes an antinode, and before the droplet discharge operation, the vibration generating means A fine particle manufacturing apparatus having a fine drive operation mode for vibrating a liquid surface of the fine particle component-containing liquid in a discharge hole.   The drive signal input to the vibration generating means in the fine drive operation mode has the same frequency as the drive signal input to the vibration generation means in the droplet discharge operation mode and has a reduced vibration amplitude. The fine particle manufacturing apparatus according to claim 4.   5. The drive signal input to the vibration generating unit in the fine drive operation mode is different in frequency from the drive signal input to the vibration generation unit in the droplet discharge operation mode. The fine particle production apparatus according to 1.   4. The method for producing fine particles according to claim 1, wherein a toner is produced as the fine particles.   The fine particle manufacturing apparatus according to claim 4, wherein the fine particles are toner.