JP2018079470A - Liquid droplet discharge device and particle production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid droplet discharge device capable of suppressing a substantial reduction in voltage or current, and stabilizing discharge performance while oscillating oscillation generation means at a high frequency.SOLUTION: A liquid droplet discharge device comprises: supply means for supplying a voltage or a current to an input side of a piezoelectric element 101; and voltage measurement means 205, or current measurement means 215, or voltage/current measurement means 225 such as measurement means for measuring a voltage or a current at an output side of the piezoelectric element 101. The supply means controls the voltage or the current supplied to the input side of the piezoelectric element 101 so as to reduce a difference between a voltage value 204, a current value 214, or voltage/current values 224 at the output side of the piezoelectric element 101 measured by the measurement means and a target voltage value or a target current value which is preset.SELECTED DRAWING: Figure 12

Description

  The present invention relates to a droplet discharge device that discharges liquid from discharge holes into droplets, and a particle manufacturing device such as a toner manufacturing device including the droplet discharge device.

  As a method for producing toner for developing an electrostatic image used in image forming apparatuses such as copying machines, printers, facsimiles, and composite machines based on the electrophotographic recording method, a pulverization method has been mainly used. In recent years, a polymerization method is increasingly employed. The polymerization method is a method of forming toner particles in an aqueous medium, and is referred to as such because it involves a 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 those utilizing suspension polymerization, emulsion aggregation, polymer suspension (polymer aggregation), ester elongation reaction, and the like are known. The toner manufactured by the polymerization method is called a polymerization toner or a chemical toner.

  The toner obtained by the polymerization method generally has the characteristics that it is easy to obtain a small particle size, the particle size distribution is narrow, and the shape is almost spherical compared to the toner obtained by the pulverization method. These characteristics bring about an effect that it is easy to obtain high image quality as an image formed by an electrophotographic method. However, it takes a long time for the polymerization process, and further, it is necessary to separate the solvent and toner particles after completion of solidification, and then repeat washing and drying, which requires a lot of time, a lot of water and a lot of energy. There is a problem.

  Also, a liquid (toner component liquid) in which the raw material components of the toner are dissolved or dispersed in an organic solvent is discharged into fine droplets using a sprayer (atomizer), etc., and dried to form a fine particle toner A toner production method called a jet granulation method is known (Patent Documents 1 to 3). According to this toner manufacturing method, since it is not necessary to use water, the time and energy required for washing and drying can be greatly reduced, and the problems of the polymerization method can be avoided.

  When producing fine particles such as toner by the jet granulation method, a liquid containing fine particles (liquid in which raw material components of fine particles are dissolved or dispersed in a solvent) from a plurality of discharge holes opened on the discharge surface of the droplet discharge device ) Is continuously discharged, and the discharged droplets are solidified to produce fine particles.

  However, in the case of producing fine particles by discharging droplets of a fine particle-containing liquid from a plurality of discharge holes opened on the discharge surface of the droplet discharge device, the droplets discharged from each discharge hole are aimed toward the discharge direction. The following problems occur if the ink is not properly discharged at the discharge speed. For example, there may be a phenomenon called coalescence where the discharged droplets come into contact with other droplets before solidifying. When such coalescence occurs, the particle diameter of the coalesced fine particles becomes larger than the desired particle diameter. In addition, for example, when the ejected droplets collide with other droplets vigorously before solidifying, a phenomenon may occur in which the droplets break and split into smaller droplets. In this case, the particle size of the fine particles obtained by solidifying the divided microdroplets is smaller than the desired particle size. When these events occur, there arises a problem that the particle size distribution of the produced fine particles is widened.

  In the fine particle manufacturing apparatus of Patent Document 4, vibration generating means for applying vibration to the liquid is provided in the liquid chamber, and by applying vibration to the liquid in the liquid chamber and forming a standing wave by liquid column resonance in the liquid chamber. Then, the liquid is discharged downward from the discharge hole formed in the region where the standing wave is antinode, and then the liquid droplets are solidified to produce fine particles. Then, by forming an air flow that flows in the droplet discharge direction, the droplet discharged from the discharge hole is conveyed not only by its own weight but also by the air flow. As a result, it is possible to suppress the droplet discharge speed from increasing and being decelerated by air resistance. As a result, it is possible to reduce contact with other droplets or collision with force before the discharged droplets solidify.

  However, in the droplet discharge device of Patent Document 4, a high frequency power source is connected to the vibration generating means in order to vibrate the vibration generating means at a high frequency of 100 [kHz] or higher. Since the piezoelectric material of the piezoelectric element used for the vibration generating means has dielectric loss, self-heating occurs when the vibration frequency is high. Even in the wiring that electrically connects the vibration generating means and the high-frequency power source, heat is generated in the wiring due to the resistance of the wiring. A part of the original power supplied to the piezoelectric element is consumed by these heat generations. As a result, the substantial voltage or current supplied to the input side of the vibration generating means is lower than the target voltage or current, and the discharge capacity is reduced. As a result, compared to when a target voltage or current is supplied, the number of vibrations per unit time is reduced and the amount of discharged particles is reduced, or the vibration width of the vibration generating means is reduced and the particle diameter is the target value. It was getting smaller.

  This problem is not limited to the case where the droplet discharge means that discharges a droplet forms a standing wave due to liquid column resonance in the liquid chamber and discharges the liquid by antinode vibration of the standing wave. is there. Further, the above problem is not limited to the case where the liquid discharged from the discharge hole is a liquid containing fine particles such as a toner component liquid. For example, the problem can also occur in a recording liquid for forming an image in an image forming apparatus.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to suppress a substantial decrease in voltage or current while vibrating the vibration generating means at a high frequency and to stabilize the discharge capacity. It is an object of the present invention to provide a droplet discharge device that can be used.

  In order to achieve the above object, the invention according to claim 1 is directed to ejecting the liquid from the ejection hole by applying vibration to the liquid in the liquid chamber in which the ejection hole is formed through the vibration plate by the vibration generating means. In the droplet discharge device for forming droplets, the apparatus includes a supply unit that supplies a voltage or a current to the input side of the vibration generating unit, and a measuring unit that measures a voltage or a current on the output side of the vibration generating unit, The supplying means reduces the difference between the voltage value or current value on the output side of the vibration generating means measured by the measuring means and the preset target voltage value or target current value. The voltage or current supplied to the input side is controlled.

  According to the present invention, it is possible to obtain a specific effect that it is possible to suppress a substantial decrease in voltage or current while vibrating the vibration generating means at a high frequency, and to stabilize the discharge capacity.

It is the schematic diagram which expanded and showed a part of droplet discharge part of the liquid column resonance type droplet discharge apparatus used by embodiment. It is sectional drawing which showed typically a part of liquid column resonance droplet formation unit which is the droplet discharge device. (A)-(d) is sectional drawing which illustrated various cross-sectional shapes employable as a cross-sectional shape of the discharge hole of the same liquid column resonance droplet formation unit. (A) to (d) show the state of the standing wave of the velocity distribution and the pressure distribution generated in the liquid in the liquid column resonance liquid chamber of the liquid column resonance droplet forming unit when N = 1, 2, and 3. It is explanatory drawing for demonstrating. (A)-(c) is explanatory drawing for demonstrating the mode of the standing wave of the velocity distribution and pressure distribution which arise in the liquid in the same liquid column resonance liquid chamber in the case of N = 4 and 5. FIG. (A)-(d) is explanatory drawing which represented typically the mode of the liquid column resonance phenomenon which arises in the same liquid column resonance liquid chamber. It is a figure which shows a mode that discharge was image | photographed by the laser shadowgraphy method. It is a characteristic view which shows the characteristic of a drive frequency and a droplet discharge speed. It is a block diagram which shows an example of a structure of the piezoelectric element drive circuit 100 of the droplet discharge apparatus which concerns on this embodiment. It is a block diagram which shows another example of a structure of the piezoelectric element drive circuit 100 of the droplet discharge apparatus which concerns on this embodiment. It is a block diagram which shows another example of a structure of the piezoelectric element drive circuit 100 of the droplet discharge apparatus which concerns on this embodiment. It is a block diagram explaining the schematic structure of a current control means. It is a schematic diagram showing an example of a toner manufacturing apparatus according to the present embodiment.

Hereinafter, an embodiment in which a fine particle production apparatus according to the present invention is applied to production of toner will be described with reference to the drawings.
The toner manufacturing apparatus according to the present embodiment supplies toner component liquid (particulate component-containing liquid), which becomes toner particles (fine particles) when the droplets are solidified, to the droplet discharge device while replenishing the toner component from the discharge hole of the droplet discharge device. The ejection operation for ejecting liquid droplets is continued. Thereafter, the discharged droplets are solidified to obtain toner particles.

  The droplet discharge device of the present embodiment preferably has a narrow particle size distribution of discharged droplets, but there is no particular limitation and a known one can be used. Examples of the droplet discharge device include a one-fluid nozzle, a two-fluid nozzle, a membrane vibration type discharge unit, a Rayleigh split type discharge unit, a liquid vibration type discharge unit, and a liquid column resonance type discharge unit. An example of a membrane vibration type discharge means is disclosed in Japanese Patent Application Laid-Open No. 2008-292976. Further, as a Rayleigh splitting type discharge means, there is one disclosed in Japanese Patent No. 4647506. Moreover, as a liquid vibration type discharge means, there is one disclosed in Japanese Patent Application Laid-Open No. 2010-102195.

  In order to ensure the productivity of the toner with a narrow droplet size distribution, vibration is imparted to the liquid in the liquid column resonance liquid chamber in which a plurality of ejection holes are formed to form a standing wave by liquid column resonance. To do. A liquid column resonance type liquid droplet ejection device that ejects liquid from the ejection holes formed in the region that becomes the antinode of the standing wave is suitable. In the present embodiment, an example in which toner is manufactured using a liquid column resonance type droplet discharge device will be described.

FIG. 1 is an enlarged schematic view showing a part of a droplet discharge section 11 of a liquid column resonance type droplet discharge apparatus used in the present embodiment.
The liquid droplet ejection unit 11 of the present embodiment includes a liquid column resonance liquid chamber 18, and this liquid column resonance liquid chamber 18 has one side wall portion (opening) among the side wall portions at both ends in the longitudinal direction (left-right direction in the drawing). It communicates with the liquid common supply path 17 via a communication path provided in the side wall portion. Further, the liquid column resonance liquid chamber 18 has a plurality of discharge holes 19 for discharging the droplets 21 to one wall portion (the bottom wall portion on the lower side in the drawing) of the wall portions connecting the side wall portions at both ends in the longitudinal direction. It has. In addition, vibration generating means 20 that generates high-frequency vibrations to form a liquid column resonance standing wave is provided on the side of the upper wall portion facing the discharge hole 19 in the liquid column resonance liquid chamber 18 via a vibration plate 22. Is provided. The vibration generating means 20 is connected to a high frequency power source (not shown).

FIG. 2 is a cross-sectional view schematically showing a part of the liquid column resonance droplet forming unit 10 which is the droplet discharge device of the present embodiment. 2 is viewed from above or below in FIG.
In the present embodiment, the liquid discharged from the droplet discharge unit 11 is a fine particle component-containing liquid in a state where the fine particle components to be manufactured are dissolved or dispersed. Since the present embodiment is an example of producing toner, this fine particle component-containing liquid will be described as a toner component liquid. The toner component liquid 14 flows into the liquid common supply path 17 of the liquid column resonance droplet forming unit 10 through a liquid supply pipe by a liquid circulation pump (not shown), and the liquid column resonance liquid chamber of each droplet discharge unit 11. 18 is replenished.

  In the toner component liquid 14 filled in the liquid column resonance liquid chamber 18, a pressure distribution is formed by the liquid column resonance standing wave generated by the vibration generating means 20. Then, the droplet 21 is discharged from the discharge hole 19 disposed in a region that is an antinode of the liquid column resonance standing wave (a region where the amplitude is large and the pressure fluctuation is large). 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 ± from the position where the amplitude of the standing wave is maximized to the position where the amplitude is minimized. The range is a quarter wavelength. If the region is an antinode of a standing wave, even if it has a configuration in which a plurality of discharge holes 19 are formed in one liquid column resonance liquid chamber 18 as in this embodiment, the size is almost uniform from each. Can be discharged. When the amount of liquid in the liquid column resonance liquid chamber 18 decreases due to the discharge of the liquid droplet 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 resonance supply chamber 17 The flow rate of the supplied liquid increases and the liquid is replenished in the liquid column resonance liquid chamber 18.

  The liquid column resonance liquid chamber 18 of the droplet discharge unit 11 is formed by joining frames formed of a material such as a metal, ceramics, or silicon having such a high rigidity that does not affect the liquid resonance frequency at the driving frequency. Is formed. Further, as shown in FIG. 1, the length L between the side wall portions 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, as shown in FIG. 2, the length (width) W between the side walls at both ends in the short direction of the liquid column resonance liquid chamber 18 is set so as not to give an extra frequency to the liquid column resonance. It is desirable to be less than half of the length L of 18.

  In order to improve productivity, it is preferable that a plurality of liquid column resonance liquid chambers 18 are arranged with respect to one liquid column resonance droplet forming unit 10. Therefore, in this embodiment, one liquid column resonance droplet is used. A configuration in which a plurality of liquid column resonance liquid chambers 18 are arranged with respect to the forming unit 10 is adopted. The number of liquid column resonance liquid chambers 18 provided for one liquid column resonance droplet forming unit 10 is not particularly limited. However, one liquid column resonance liquid chamber having 100 to 2000 liquid column resonance liquid chambers 18 is provided. The droplet forming unit 10 is preferable because both operability and productivity can be realized. In the present embodiment, a plurality of liquid column resonance liquid chambers 18 communicate with one liquid common supply path 17.

Further, the vibration generating means 20 in the droplet discharge unit 11 is not particularly limited as long as it can be driven at a predetermined frequency, but has a structure in which a diaphragm 22 is attached to a piezoelectric element as in this embodiment. preferable. The diaphragm 22 is provided so as to isolate the piezoelectric element from the liquid column resonance liquid chamber 18 so that the piezoelectric element does not come into contact with the liquid. Examples of the piezoelectric body of the piezoelectric element include piezoelectric ceramics such as lead zirconate titanate (PZT). In general, the piezoelectric element is often used by being laminated because of its small displacement. 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 18. For example, a configuration in which one piezoelectric material is divided into a plurality of piezoelectric bodies in accordance with the arrangement of the liquid column resonance liquid chambers, and each liquid column resonance liquid chamber can be individually controlled by each piezoelectric body is preferable.

The outlet side diameter of the discharge hole 19 is preferably in the range of 1 [μm] to 40 [μm].
If it is smaller than 1 [μm], the formed droplets will be very small, and toner may not be obtained. In particular, when solid fine particles such as a pigment are contained as a constituent component of the toner, the solid fine particles may block the discharge holes 19 and may reduce the productivity of the toner. On the other hand, if it is larger than 40 [μm], the diameter of the droplet is large, so that it is dried and solidified to obtain a toner particle diameter of 3 [μm] or more and 6 [μm] or less. Needs to be diluted to a very dilute solution. In this case, a large amount of drying energy is required to obtain a certain amount of toner, which is inconvenient.

  In the present embodiment, the row of discharge holes (see FIG. 1) in which a plurality of discharge holes 19 are arranged is arranged in the width direction in the liquid column resonance liquid chamber 18 (left-right direction in FIG. 2), as shown in FIG. ) Are arranged in parallel. With such a configuration, more liquid droplets can be ejected by a single ejection operation, which increases production efficiency. Since the liquid column resonance frequency varies depending on the arrangement of the discharge holes 19, it is desirable that the liquid column resonance frequency is appropriately determined while confirming the discharge of the droplet.

FIGS. 3A to 3D are cross-sectional views illustrating various cross-sectional shapes that can be adopted as the cross-sectional shape of the discharge hole 19.
In the present embodiment, the case where the cross-sectional shape of the discharge hole 19 is a tapered shape whose diameter decreases toward the outlet side as shown in FIG. 1 is illustrated, but this cross-sectional shape is appropriately selected. can do.
The cross-sectional shape of the discharge hole 19 shown in FIG. 3A is a cross-sectional shape in which the diameter becomes narrower while having a round shape (curved shape) from the inlet side to the outlet side of the discharge hole 19. This cross-sectional shape maximizes the pressure applied to the liquid near the outlet of the discharge hole 19 when the discharge hole thin film 41 constituting the bottom wall portion of the liquid column resonance liquid chamber 18 in which the discharge hole 19 is formed vibrates. For this reason, it is a preferable shape for the stabilization of discharge.
The cross-sectional shape of the discharge hole 19 shown in FIG. 3 (b) is a cross-sectional shape having a taper shape such that the diameter becomes narrower from the inlet side to the outlet side of the discharge hole 19 with a certain angle. The embodiment is employed. In this cross-sectional shape, since it is a tapered shape, like the cross-sectional shape shown in FIG. 3A, the liquid is applied near the outlet of the discharge hole 19 when the discharge hole thin film 41 vibrates. The pressure can be increased. The taper angle 42 can be appropriately changed, but is preferably in the range of more than 60 ° and not more than 90 °. This is because when the nozzle angle 24 is 60 ° or less, it is difficult for pressure to be applied to the liquid, and further, the processing of the discharge hole thin film 41 becomes difficult. On the other hand, when the nozzle angle 24 is 90 °, the cross-sectional shape as shown in FIG. 3C is obtained, but pressure is not easily applied near the outlet of the discharge hole 19, so a suitable angle range of the taper angle 42 is obtained. As a result, 90 ° is the maximum value. When the taper angle 42 is larger than 90 °, no pressure is applied to the vicinity of the outlet of the discharge hole 19, so that the droplet discharge becomes very unstable.
The sectional shape of the discharge hole 19 shown in FIG. 3D is a combination of the sectional shape shown in FIG. 3A and the sectional shape shown in FIG. In this way, the cross-sectional shape may be changed step by step.

Next, the mechanism of droplet formation by the liquid column resonance droplet forming unit 10 will be described.
First, the principle of the liquid column resonance phenomenon that occurs in the liquid column resonance liquid chamber 18 in the droplet discharge section 11 shown in FIG. 1 will be described.
When the sound velocity of the toner component liquid in the liquid column resonance liquid chamber is “c” and the drive frequency applied to the toner component liquid as a medium from the vibration generating unit 20 is “f”, the wavelength λ at which the liquid resonance occurs is It can be calculated from the following equation (1).
λ = c / f (1)

In the present embodiment, the side wall portion (opening side wall portion) of the liquid column resonance liquid chamber 18 in which the communication passage for communicating with the liquid common supply passage 17 is formed is the opposite side wall portion (where the communication passage is not formed) ( It can be considered that it is equivalent to the closed side wall. In this case, when the longitudinal length L of the liquid column resonance liquid chamber 18 coincides with an even multiple of a quarter of the wavelength λ, the vibration in the liquid column resonance liquid chamber 18 is changed by the vibration of the vibration generating means 20. Resonant vibration occurs most efficiently. The optimum liquid column resonance condition in which such liquid column resonance occurs most efficiently can be expressed by the following equation (2). Note that the optimum condition of the liquid column resonance shown in the above formula (2) holds true even when the both side walls in the longitudinal direction of the liquid column resonance liquid chamber 18 are completely opened.
L = (N / 4) × λ (2)

  On the other hand, when one of the longitudinal side walls of the liquid column resonance liquid chamber 18 is open and the other is closed, the length L of the liquid column resonance liquid chamber 18 is the wavelength. Liquid column resonance is most efficiently formed when it coincides with an odd multiple of λ. In other words, the optimum condition for liquid column resonance in this case is expressed by an odd number of “N” in the above formula (2).

The driving frequency f with the highest liquid column resonance efficiency is represented by the following equation (3) from the above equations (1) and (2). However, in reality, since the liquid has a viscosity that attenuates resonance, the vibration is not amplified infinitely. It has a Q value and, as shown in equations (4) and (5) described later, the above equation Resonance also occurs at a frequency in the vicinity of the most efficient drive frequency f shown in (3).
f = N × c / (4L) (3)

FIGS. 4A to 4D are diagrams for explaining the standing wave of the velocity distribution and the pressure distribution generated in the liquid in the liquid column resonance liquid chamber 18 when N = 1, 2, and 3. FIG.
However, FIG. 4A is an example in the case of N = 1, where one of the longitudinal ends of the liquid column resonance liquid chamber 18 is open and the other is closed. . FIG. 4B shows an example in which N = 2 and both ends in the longitudinal direction of the liquid column resonance liquid chamber 18 are closed. FIG. 4C shows an example in which N = 2 and the both ends in the longitudinal direction of the liquid column resonance liquid chamber 18 are open. FIG. 4D shows an example in which N = 3, where one of the longitudinal ends of the liquid column resonance liquid chamber 18 is open and the other is closed.

FIGS. 5A to 5C are explanatory views for explaining the standing wave of the velocity distribution and the pressure distribution generated in the liquid in the liquid column resonance liquid chamber 18 when N = 4 and 5. FIG. FIG.
However, FIG. 5A shows an example where N = 4 and both end portions in the longitudinal direction of the liquid column resonance liquid chamber 18 are closed. FIG. 5B is an example in the case where N = 4 and both end portions in the longitudinal direction of the liquid column resonance liquid chamber 18 are open. FIG. 5C shows an example in which N = 5, where one of the longitudinal ends of the liquid column resonance liquid chamber 18 is open and the other is closed.

  4 and 5, the solid line represents the velocity standing wave, and the dotted line represents the pressure standing wave. The wave generated in the liquid in the liquid column resonance liquid chamber 18 is actually a sparse wave (longitudinal wave), but in FIG. 4 and FIG. 5, this is expressed in the form of a sine wave (cosine wave). . For example, when looking at the velocity distribution of FIG. 4A, it can be intuitively understood that the amplitude of the velocity distribution becomes zero at the closed side wall portion that is closed, and the amplitude becomes maximum at the opened side wall portion, Since it is easy to understand, sine wave notation is used here. Since the standing wave pattern varies depending on the open / closed state of the both side walls in the longitudinal direction (combination pattern of the open end and the fixed end), FIGS. 4 and 5 illustrate the liquid column resonance liquid chamber of the present embodiment for the sake of explanation. The combination pattern of the open end and the fixed end that do not match 18 is also shown.

  As will be described in detail later, the end condition is determined by the state of the opening of the discharge hole 19 and the opening of the communication path that connects the liquid column resonance liquid chamber 18 and the liquid common supply path 17. In acoustics, at the open end (open end), the moving speed of the medium (liquid) in the longitudinal direction is maximum, and the pressure is zero. On the other hand, at the fixed end (closed end), on the contrary, the moving speed of the medium becomes zero and the pressure becomes maximum. The fixed end (closed end) is considered as an acoustically hard wall, and on the assumption that the wave is completely reflected, if the end is ideally completely closed or open, the wave is superposed as shown in FIG. It is assumed that a standing wave as shown in FIG. 5 is generated. If there are openings such as the discharge holes 19 and the communication passages as in the liquid column resonance liquid chamber 18 of the present embodiment, the number of the discharge holes 19, the positions of the discharge holes 19, the size and position of the communication passages, and the like. However, the standing wave pattern fluctuates. Therefore, the actual resonance frequency appears at a position shifted from the ideal resonance frequency obtained from the above equation (3). However, even if there is such a shift, there is no problem because the drive frequency may be adjusted as appropriate while confirming the actual discharge state.

  1200 [m / s] is used as the sound velocity c of the liquid, the longitudinal length L of the liquid column resonance liquid chamber 18 is 1.85 [mm], and there are wall portions at both ends in the longitudinal direction. In the case of N = 2 resonance mode equivalent to a model in which both ends are fixed ends, from the above equation (2), the ideal resonance frequency that causes liquid column resonance most efficiently in the liquid in the liquid column resonance liquid chamber 18 is 324 [kHz]. On the other hand, 1200 [m / s] is used as the sound velocity c of the liquid, the longitudinal length L of the liquid column resonance liquid chamber 18 is 1.85 [mm], and there are wall portions at both ends. In the case of N = 4 resonance mode equivalent to a model in which both ends are fixed ends, from the above equation (2), the ideal resonance frequency that causes liquid column resonance most efficiently in the liquid in the liquid column resonance liquid chamber 18 is 648 [kHz]. Thus, higher-order resonance can be used also in the liquid column resonance liquid chamber 18 having the same configuration.

  The liquid column resonance liquid chamber 18 of the present embodiment has a configuration in which both ends in the longitudinal direction are equivalent to the closed end, or can be described as an acoustically soft wall due to the opening of the discharge hole 19. It is preferable for increasing the resonance frequency. However, the configuration is not limited thereto, and for example, a configuration in which both ends in the longitudinal direction are equivalent to the open ends may be employed. The influence of the opening of the discharge hole 19 here means that the acoustic impedance is reduced, and in particular, the compliance component is increased. As shown in FIG. 1, the discharge hole 19 provided in the liquid column resonance liquid chamber 18 of the present embodiment is arranged so as to be close to one end side in the longitudinal direction (the side opposite to the liquid common supply path 17). Therefore, the one end side can be regarded as an open end (open end) due to the influence of the opening of the discharge hole 19. As a result, when the both end walls in the longitudinal direction of the liquid column resonance liquid chamber 18 are equivalent to the closed ends as shown in FIG. 4B and FIG. 5A, only the resonance mode in which both ends are fixed ends is used. It is also possible to use a resonance mode in which one end is an open end and the other end is a fixed end.

  In addition, the number of ejection holes 19, the arrangement of the ejection holes 19, and the cross-sectional shape of the ejection holes 19 are factors that determine the driving frequency, and the driving frequency can be appropriately determined according to this. For example, the closer the arrangement of the discharge holes 19 is to the one end side in the longitudinal direction, the more restrained the wall portion of the liquid column resonance liquid chamber 18 becomes at the end portion in the longitudinal direction. Therefore, as the arrangement of the discharge holes 19 is moved closer to one end in the longitudinal direction, the end in the longitudinal direction is almost close to the opening end, and the drive frequency is changed. Further, for example, when the number of the discharge holes 19 is increased, the restriction by the wall portion of the liquid column resonance liquid chamber 18 becomes loose at one end in the longitudinal direction where the arrangement of the discharge holes 19 is approached, and the end in the longitudinal direction is almost the open end. It is changed so that the drive frequency becomes high in a state close to. In addition, for example, when the cross-sectional shape of the discharge hole 19 is changed or the dimension of the discharge hole 19 is changed, the drive frequency needs to be changed.

When an AC voltage is applied to the vibration generating means 20 at the drive frequency determined in this way, the piezoelectric element of the vibration generating means 20 is deformed according to the voltage fluctuation, and thereby the diaphragm 22 is displaced. As a result, vibration corresponding to the driving frequency is applied to the liquid in the liquid column resonance liquid chamber 18, and a liquid column resonance standing wave is generated in the liquid in the liquid column resonance liquid chamber 18. However, if the liquid column resonance standing wave has a frequency close to the drive frequency at which it is most efficiently generated, the liquid column resonance standing wave is generated. Specifically, when the distance between the longitudinal wall on the liquid common supply path 17 side and the discharge hole arranged closest to the liquid common supply path 17 is Le, the length of the liquid column resonance liquid chamber is defined as Le. The length L between the directional walls is used. The range of the driving frequency f for generating the liquid column resonance standing wave can be defined by, for example, the following equations (4) and (5). By vibrating the vibration generating means 20 using a drive waveform whose main component is the drive frequency f within the range determined by these formulas (4) and (5), a liquid column resonance is induced to cause a droplet to It is possible to discharge appropriately from the discharge hole 19. However, the ratio of L to Le is preferably Le / L> 0.6.
N × c / (4L) ≦ f ≦ N × c / (4Le) (4)
N × c / (4L) ≦ f ≦ (N + 1) × c / (4Le) (5)

  Using the principle of the liquid column resonance phenomenon described above, in this embodiment, a liquid column resonance pressure standing wave is formed in the liquid column resonance liquid chamber 18 shown in FIG. The continuous droplet discharge is caused from the discharge hole 19. Therefore, it is preferable to dispose the discharge hole 19 at a position where the standing wave of the pressure fluctuates the most, because the discharge efficiency is increased and the driving voltage can be further suppressed.

  Further, although one discharge hole 19 may be provided for one liquid column resonance liquid chamber 18, it is preferable to arrange a plurality of discharge holes 19 for one liquid column resonance liquid chamber 18 from the viewpoint of productivity. Specifically, it is preferably between 2 and 100. When the number exceeds 100, if the droplets are appropriately discharged from the respective discharge holes 19, it is necessary to set a high driving voltage to the vibration generating means 20, and the behavior of the piezoelectric element of the vibration generating means 20 is not good. It tends to be stable.

  When a plurality of discharge holes 19 are formed for one liquid column resonance liquid chamber 18, the pitch between the discharge holes is preferably 20 [μm] or more. When the pitch between the discharge holes is smaller than 20 [μm], there is a high probability that the liquid droplets discharged from the adjacent discharge holes come into contact with each other to form large liquid droplets, and the toner particle size distribution deteriorates. This is because the possibility increases.

Next, the state of the liquid column resonance phenomenon that occurs in the liquid column resonance liquid chamber 18 in the droplet discharge section 11 in the liquid column resonance droplet forming unit 10 will be described.
6A to 6D are explanatory views schematically showing the state of the liquid column resonance phenomenon that occurs in the liquid column resonance liquid chamber 18.
The solid line written in the liquid column resonance liquid chamber 18 in FIG. 6 shows the velocity distribution obtained by plotting the velocity at an arbitrary measurement position in the longitudinal direction of the liquid column resonance liquid chamber 18. The direction from the closed side wall portion side on the left side in the figure to the open side wall portion on the right side in the figure is positive, and the opposite direction is negative. Further, the dotted line written in the liquid column resonance liquid chamber 18 in FIG. 6 shows the pressure distribution obtained by plotting the pressure value at an arbitrary measurement position in the longitudinal direction of the liquid column resonance liquid chamber 18. Positive pressure is positive with respect to atmospheric pressure, negative pressure is negative.

  In the present embodiment, as shown in FIG. 1, the height h <b> 1 (= about) from the bottom surface of the liquid column resonance liquid chamber 18 in the droplet discharge unit 11 to the lower end of the communication path communicating with the liquid common supply path 17. 80 [μm]) is set to about twice the height h2 (= about 40 [μm]) of the communication port. Therefore, the liquid column resonance liquid chamber 18 of the present embodiment can be approximately considered that both ends in the longitudinal direction are substantially fixed ends. FIGS. 6A to 6D show temporal changes in the velocity distribution and the pressure distribution under such an idea.

  FIG. 6A shows a pressure waveform and a velocity waveform in the liquid column resonance liquid chamber 18 at the time of droplet discharge. At this time, the liquid portion on the closed side wall portion side in the liquid column resonance liquid chamber 18, that is, the liquid portion in the liquid chamber region where the discharge hole 19 is provided (liquid in the vicinity of the discharge hole) has a maximum pressure. . As a result, the meniscus pressure increases, and the liquid comes out from each discharge hole 19. Thereafter, as shown in FIG. 6B, the pressure of the liquid in the vicinity of the discharge hole 19 decreases, and the liquid droplet 21 is discharged from the discharge hole 19 by shifting in the negative pressure direction.

  Thereafter, as shown in FIG. 6C, the pressure of the liquid in the vicinity of the discharge hole 19 becomes minimum. From this time, replenishment of the toner component liquid 14 from the liquid common supply path 17 to the liquid column resonance liquid chamber 18 starts. Then, as shown in FIG. 6D, the pressure of the liquid in the vicinity of the discharge hole 19 gradually increases and shifts in the positive pressure direction. At this time, the replenishment of the toner component liquid 14 is completed, and the pressure of the liquid near the discharge hole 19 of the liquid column resonance liquid chamber 18 is maximized again as shown in FIG.

  As described above, in the liquid near the discharge hole 19 in the liquid column resonance liquid chamber 18, a standing wave due to the liquid column resonance is generated by the high frequency driving of the vibration generating means 20, and the pressure is the position where the pressure fluctuates most greatly. Discharge holes 19 are arranged at locations corresponding to antinodes of standing waves due to liquid column resonance. From this, the droplet 21 is continuously discharged from the discharge hole 19 according to the antinode period.

  Next, an example of a configuration in which droplets are actually ejected by the liquid column resonance phenomenon will be described. An example of this is a resonance mode in which 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 in FIG. In addition, the first to fourth toner discharge holes are arranged at the antinodes of the N = 2 mode pressure standing wave, and the laser shadowgraphy is performed with a sine wave having a drive frequency of 340 [kHz]. FIG. 7 shows a state photographed by the method. As can be seen from the figure, it is possible to discharge droplets having a uniform diameter and a substantially uniform speed. FIG. 8 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 FIG. 8, in the first to fourth nozzles, when the drive frequency is around 340 [kHz], the discharge speed from each nozzle is uniform and the maximum discharge speed. From this characteristic result, it can be seen that, in the second mode of the liquid column resonance frequency, 340 [kHz], uniform discharge is realized at the antinode position of the liquid column resonance standing wave. Further, from the characteristic results of FIG. 8, 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 channel. The frequency of power supplied to the piezoelectric element is preferably in the range of 100 to 1000 [kHz]. When the frequency is lower than 100 [kHz], the productivity of the particles is low, and when the frequency exceeds 1000 [kHz], resonance in the horizontal direction of the liquid column resonance liquid chamber is likely to occur, resulting in uneven discharge.

FIG. 9 is a block diagram showing an example of the configuration of the piezoelectric element driving circuit 100 of the droplet discharge device according to the present embodiment. In FIG. 9, it is the structure of the general power amplifier corresponding to a high frequency, and alternating voltage is given to the piezoelectric element of the vibration generation means used as a load. The vibration generating means is expressed as a capacitive load, and repeats discharging and charging based on the drive signal. The piezoelectric element drive circuit 100 includes waveform generation means 102 that generates a drive signal having an AC waveform applied to the piezoelectric element 101. Further, the preamplifier 103 that amplifies the drive signal output from the waveform generation means and supplies the piezoelectric element 101 with the preamplifier 103 and the voltage on the output side of the piezoelectric element 101 that supplies the drive signal that is the output signal of the main up 104 and the main up 104 An oscilloscope 106 is provided as a voltmeter for measurement. The drive signal output from the waveform generation unit 102 is supplied to the positive terminal of the preamplifier 103, and is amplified to a target preamplified value by a control signal from a control unit (not shown) supplied from the negative terminal of the preamplifier 103. The first drive signal is supplied to the positive terminal of the main up 104. In the main up 104, the second drive signal, which is supplied from the negative terminal and amplified to a target amplification value by a control signal from a control unit (not shown), is supplied to the piezoelectric element 101. In the piezoelectric element 101, an AC voltage is supplied. Accordingly, the piezoelectric element 12 is charged / discharged and vibrates. The oscilloscope 106 measures the peak value of the AC voltage on the output side of the piezoelectric element 101. The measured value is supplied to a drive control unit described later. Specifically, the voltage supplied to the input side of the piezoelectric element 101 decreases with heat generation due to the resistance value R1 of the wiring resistance. Furthermore, the voltage on the output side of the piezoelectric element 101 decreases with self-heating due to dielectric loss due to the resistance R ₀ and the capacitor capacitance C _{1 of} the piezoelectric element 101. By measuring the voltage on the output side of the piezoelectric element 101 with an oscilloscope 106 having an infinitely large impedance, the voltage on the output side of the piezoelectric element 101 can be accurately measured. The difference between the measured voltage value on the output side of the piezoelectric element 101 that can be measured and the target voltage value is obtained, and the voltage that the waveform generation means 102 supplies to the input side of the piezoelectric element 101 is controlled so that the difference becomes small. To do.

FIG. 10 is a block diagram showing another example of the configuration of the piezoelectric element driving circuit 100 of the droplet discharge device according to the present embodiment. In FIG. 10, a piezoelectric element driving circuit 100 includes an oscillator 110 that generates reference signals (common reference signals) Vs that define the waveforms of control signals Vc1 and Vc2 that control the output of a driving signal applied to the piezoelectric element 101. doing. In addition, an FET drive circuit 111 is provided as a control signal output unit that outputs two control signals for the high-side FET 112 and the low-side FET 113 based on the one reference signal (common reference signal) Vs. To the output voltage V2 of the DC power source 114, and low FET113 for discharging high-side FET112 for charging are connected in series, the piezoelectric element via an inductor L to the middle point (connecting point) and the resistor _{R 1} 101 Is connected. The high-side FET 112 and the low-side FET 113 are controlled independently from each other by control signals Vc1 and Vc2 from the FET drive circuit 111. The FET drive circuit 111 generates control signals Vc1 and Vc2 based on the reference signal Vs. The FET drive circuit 111 that generates the control signal Vc1 is connected to the gate as the control terminal of the high-side FET 112, and the FET drive circuit 111 that generates the control signal Vc2 is connected to the gate as the control terminal of the low-side FET 113. Yes.

In the piezoelectric element driving circuit 100 configured as described above, the phases of the control signals Vc1 and Vc2 are adjusted so that the high-side FET 112 and the low-side FET 113 are not turned on at the same time. Assuming that the voltage applied to the piezoelectric element 12 is Vp, for example, as shown in Table 1 below, the high-side FET 112 and the low-side FET 113 are ON / OFF controlled by the control signals Vc1 and Vc2. As a result, the voltage applied to the piezoelectric element 101 changes to charge / discharge the piezoelectric element 12, and the piezoelectric element 101 vibrates. The ammeter 115 measures the direct current value of the direct current power supply 114, and the voltmeter 116 measures the voltage value of the direct current power supply 114. The oscilloscope 117 of the voltmeter measures the peak value of the AC voltage of the piezoelectric element 101. The measured value is supplied to a drive control unit described later. Specifically, the voltage on the output side of the piezoelectric element 12 decreases due to heat generation due to wiring resistance (resistance value R ₁ ) and self-heat generation due to dielectric loss due to the resistance R ₀ of the piezoelectric element 101 and the capacitor capacitance C _1. . By measuring this reduced voltage with an oscilloscope 106 having an infinitely large impedance, the voltage on the output side of the piezoelectric element 12 can be accurately measured. The difference between the measured voltage value on the output side of the piezoelectric element 12 that can be measured and the target voltage value is obtained, and the voltage V2 of the DC power supply 114 is controlled so that the difference becomes smaller. Alternatively, the same control as described above can be performed by measuring the ammeter 115 based on the measured value.

  When the driving of the high-side FET 112 and the low-side FET 113 is repeated at a constant period (frequency f), the voltage applied to the piezoelectric element 101 changes in a trapezoidal shape with little rising noise.

FIG. 11 is a block diagram illustrating another example of the configuration of the piezoelectric element driving circuit 100 of the droplet discharge device according to the present embodiment. In FIG. 11, the drive signal generation circuit includes a signal generation circuit 120 that outputs a charge / discharge pulse 121 that defines the charge / discharge timing of the piezoelectric element 101 as a vibration generating unit, and a voltage amplification circuit 122 for the charge / discharge pulse 121. have. Further, based on the charge / discharge pulse 121, push-pull connected NPN bipolar transistor (hereinafter referred to as “NPN transistor”) 123 and PNP bipolar transistor (hereinafter referred to as “PNP transistor”) 124 are switched. A current amplifying circuit that outputs a common drive signal COM amplified by operation to the piezoelectric element 101 is provided. Here, the piezoelectric element 101 is represented as a capacitive load C1, and when the drive signal COM is applied, the piezoelectric element 101 repeats discharging and charging based on the drive signal COM. The ammeter 125 measures the direct current value of the direct current power supply 114, and the voltmeter 126 measures the voltage value of the direct current power supply 114. The oscilloscope 127 of the voltmeter measures the peak value of the AC voltage of the piezoelectric element 101. The measured value is supplied to a drive control unit described later. Specifically, the voltage on the output side of the piezoelectric element 12 decreases with heat generation due to the wiring resistance (resistance value R ₁ ) and self-heat generation due to dielectric loss due to the resistance R ₀ of the piezoelectric element 101 and the capacitor capacitance C ₁ . By measuring this reduced voltage with an oscilloscope 106 having an infinitely large impedance, the voltage on the output side of the piezoelectric element 12 can be accurately measured. The difference between the measured voltage value on the output side of the piezoelectric element 12 that has been measured and the target voltage value is obtained, and the voltage V2 of the DC power supply 124 is controlled so that the difference becomes smaller. Alternatively, the same control as described above can be performed by measuring the ammeter 125 based on the measured value.

  In the piezoelectric element driving circuits shown in FIGS. 9 to 11, any of known means can be used as the current measuring means and the voltage measuring means, but the voltage waveform is acquired by various oscilloscopes and the peak value is output as a result. The means is easy to use in AC voltage measurement. Moreover, although an oscilloscope can be used similarly for the measurement of alternating current, it can be measured by adding current detection means such as a clamp meter. Further, depending on the form of the power amplifier circuit, it is possible to use a DC voltage or a DC current output from a DC power supply that supplies power as a representative value. Further, in the case of a general-purpose power source, a current or voltage may be output, and this can be used.

  Next, the configuration of the drive control unit in the droplet discharge device of the present embodiment will be described with reference to the drawings. FIG. 12 is a block diagram illustrating a schematic configuration of the drive control unit. 12A is a block diagram illustrating a schematic configuration of the voltage control unit, FIG. 12B is a block diagram illustrating a schematic configuration of the current control unit, and FIG. 12C illustrates a schematic configuration of the voltage control unit. FIG. The drive control unit in FIG. 12 performs feedback control. As the simplest control, the difference between the measured value obtained by the current measuring means or the voltage measuring means and the target value is confirmed at regular time intervals. When (target value)> (measured value), the set value is slightly increased, and when (target value) <(measured value), the set value is decreased slightly.

  In the voltage control unit of FIG. 12A, the voltage of the set voltage value is output from the output unit (not shown) of the comparison adjusting unit 202 to the input side of the vibration generating unit 203 based on the set voltage value 201 set by the host device. Applied. The voltage on the output side of the vibration generating means 203 according to the applied voltage is measured by the voltage measuring means 204, for example, the oscilloscope 106 in FIG. 9, the oscilloscope 117 in FIG. 10, or the oscilloscope 127 in FIG. A control unit (not shown) of the comparison adjustment unit 202 calculates a difference between the measured voltage measurement value and a preset target voltage value, and outputs the difference from the control unit of the comparison adjustment unit 202 so that the difference becomes small. A control signal is output to the unit. The feedback control as described above is performed.

  In the current control unit of FIG. 12B, the current of the set current value is output from the output unit (not shown) of the comparison adjustment unit 212 to the input side of the vibration generation unit 213 based on the set current value 211 set by the host device. Supplied. The current (clamp current value) on the output side of the vibration generating means according to the supplied current is measured by the current measuring means 214, for example, the ammeter 115 in FIG. 10 or the ammeter 125 in FIG. A control unit (not shown) of the comparison adjustment unit 212 calculates a difference between the measured current measurement value and a preset target current value, and outputs the difference from the control unit of the comparison adjustment unit 202 so that the difference becomes small. A control signal is output to the unit. The feedback control as described above is performed.

  In the power control unit in FIG. 12C, the power of the set power value is output from the output unit (not shown) of the comparison adjusting unit 222 to the input side of the vibration generating unit 223 based on the set power value 221 set by the host device. Supplied. The electric power on the output side of the vibration generating means accompanying the supplied electric power is converted into voltage measuring means / current measuring means 224, for example, the ammeter 115 and voltmeter 116 in FIG. 10, or the ammeter 125 and voltmeter 126 in FIG. measure. A control unit (not shown) of the comparison adjustment unit 222 calculates a difference between the measured power measurement value and a preset target power value, and outputs the difference from the control unit of the comparison adjustment unit 202 so that the difference becomes small. A control signal is output to the unit. The feedback control as described above is performed.

FIG. 13 is a schematic diagram illustrating an example of a toner manufacturing apparatus that performs the toner manufacturing method according to the present embodiment.
The toner manufacturing apparatus 300 mainly includes the above-described liquid column resonance droplet forming unit 310, a dry collection unit 320, and a toner component liquid replenishment unit 330.

  The toner component liquid replenishment unit 330 includes a toner component liquid tank 332 that stores the toner component liquid 331. The toner component liquid tank 332 is connected to the liquid column resonance droplet forming unit 310 via the toner component liquid supply channel 333. A liquid circulation pump 334 that pumps the toner component liquid 331 in the toner component liquid supply flow path 333 is connected to the toner component liquid supply flow path 333. By driving the liquid circulation pump 334, the toner component liquid 331 in the toner component liquid tank 332 is supplied to the liquid column resonance droplet forming unit 310 through the toner component liquid supply channel 333.

  The toner component liquid tank 332 is connected to the liquid column resonance droplet forming unit 310 via a liquid return pipe 335. Among the toner component liquids 331 supplied from the toner component liquid supply flow path 333 to the liquid column resonance droplet forming unit 310, those not replenished to the liquid column resonance liquid chamber of the liquid column resonance droplet forming unit 310 are liquid. The circulation pump 334 is driven to return to the toner component liquid tank 332 through the liquid return pipe 335.

  In the present embodiment, the toner component liquid supply flow path 333 is provided with a pressure measuring device P1, and the dry collection unit 320 is provided with a pressure measuring device P2. The liquid feeding pressure to the liquid column resonance droplet forming unit 310 and the pressure in the dry collection unit 320 are managed based on the measurement results of these pressure measuring devices P1 and P2. At this time, if the pressure of the pressure measuring device P1 is greater than the pressure of the pressure measuring device P2, the toner component liquid 331 may ooze out from the ejection hole. On the other hand, if the pressure of the pressure measuring device P1 is smaller than the pressure of the pressure measuring device P2, there is a possibility that gas enters the liquid column resonance droplet forming unit 310 and the discharge stops. Therefore, it is desirable that the pressure of the pressure measuring device P1 and the pressure of the pressure measuring device P2 have a substantially equal relationship.

  The dry collection unit 320 is provided with a chamber 321, and a liquid column resonance droplet forming unit 310 is installed in the chamber 321. A descending airflow (conveying airflow) 323 is sent into the chamber 321 from the conveying airflow inlet 322, and the droplets 21 discharged from the liquid column resonance droplet forming unit 310 are not only gravity but also the descending airflow 323. Is also transported downward. The liquid droplets conveyed downward in the chamber 321 are dried and solidified during the conveyance, discharged from the collection outlet 324, sent to the solidified particle collecting means 325, and collected. The particles collected by the solidified particle collecting means 325 are then sent to a drying means 326 that performs a secondary drying process as necessary.

  When the ejected droplets come into contact with each other before drying, a phenomenon called coalescence in which the droplets coalesce into one large particle occurs, and the toner particle size distribution spreads. Therefore, in order to obtain toner particles having a narrow particle size distribution, it is necessary to secure the distance between the discharged droplets. However, the ejected droplets have a constant initial velocity, but gradually become stalled due to air resistance. For this reason, the liquid droplets discharged later may catch up with the stalled liquid droplets, which may cause coalescence. Since such a coalescence phenomenon occurs constantly, when the particles are collected, the particle size distribution is greatly deteriorated. In order to prevent such a coalescence phenomenon, in the present embodiment, a drop in the velocity of the droplets is prevented by the descending airflow so that the droplets do not come into contact with each other.

  Although the direction of the carrier airflow (downward airflow 323) in the present embodiment is directed downward, a carrier airflow directed in the lateral direction with respect to the droplet discharge direction can also be employed. However, in this case, it is desirable to form the transport airflow so that the trajectories of the droplets transported by the transport airflow from the ejection holes do not overlap. The direction of the carrier airflow may not be transverse to the droplet ejection direction, but may be oblique to the droplet ejection direction, but has an angle such that the ejected droplets are separated. It is desirable.

  In the present embodiment, both the prevention of coalescence and the conveyance to the solidified particle collecting means are realized by the descending airflow. However, the first airflow and the solidified particle collecting means for preventing the coalescence are realized. You may form separately the 2nd airflow for conveying to. In this case, it is desirable that the flow rate of the first air stream is equal to or higher than the moving speed of the droplets during discharge. If the flow velocity of the first air stream is slower than the droplet moving speed at the time of ejection, there is a possibility that the function of preventing contact between the droplets, which is the original purpose of the first air stream, may not be performed. About the other characteristic of 1st airflow, you may add suitably the conditions that droplets do not contact, and it does not necessarily need to be the same as the characteristic of 2nd airflow. For example, a chemical substance that promotes solidification of the droplets may be mixed in the first air stream, or a physical action may be performed so as to promote solidification of the droplets.

  The descending airflow of the present embodiment may be, for example, a laminar flow, a swirling flow, a turbulent flow, or the like. There are no particular limitations on the type of gas that constitutes the downdraft, and it may be air or a nonflammable gas such as nitrogen. Further, the temperature of the descending airflow can be adjusted as appropriate, and it is desirable that there is no fluctuation during production. Also, means for changing the airflow state of the descending airflow may be provided in the chamber. Further, the downward airflow may be used not only to prevent contact between droplets but also to prevent adhesion to the inner wall of the chamber.

  As shown in FIG. 13, in this embodiment, when the amount of residual solvent contained in the toner particles collected by the solidified particle collecting means 325 is large, the drying means is used as necessary to reduce this. Secondary drying is performed by 326. As the secondary drying, general known drying means such as fluidized bed drying or vacuum drying can be used. When the organic solvent remains in the toner, not only the toner characteristics such as heat-resistant storage stability, fixing property, and charging characteristics fluctuate with time, but also the organic solvent volatilizes during heat-fixing during the image forming operation. For this reason, there is a high possibility that the user and various devices and peripheral devices in the image forming apparatus will be adversely affected, and it is desired to perform sufficient drying.

Hereinafter, the toner manufactured in this embodiment will be described.
The toner manufactured in this embodiment contains at least a resin, a colorant, and a wax, and optionally contains a charge adjusting agent, an additive, and other components.

First, the toner component liquid used in this embodiment will be described.
The toner component liquid may be in a liquid state in which the above-described toner component is dissolved or dispersed in a solvent, or may be free from a solvent as long as it is liquid under the conditions of discharge, and a part or all of the toner component is melted. It is mixed in a state and presents a liquid state. As the toner material, the same materials as known electrophotographic toners can be used as long as the toner component liquid can be adjusted. Such a toner component liquid is ejected from the liquid column resonance droplet forming unit into microdroplets, and the microdroplets dried and solidified are collected by the solidified particle collecting means 325. Toner particles are produced.

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.
The molecular weight distribution of the binder resin by GPC (gel permeation chromatography) and at least one peak in the region of molecular weight of 3,000 to 50,000 are preferable from the viewpoint of toner fixing property and offset resistance. In addition, as a THF soluble component, a binder resin in which a component having a molecular weight of 100,000 or less is 60 to 100 [%] is preferable, and a binder having at least one peak in a region having a molecular weight of 5,000 to 20,000. A resin is more preferable. What has 60 [mass%] or more of resin whose acid value of binder resin has 0.1-50 [mgKOH / g] is preferable.
In this embodiment, 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 embodiment, known materials used for electrophotographic toners can be used. For example, (1) iron oxide containing magnetic iron oxide such as magnetite, maghemite and ferrite, and other metal oxides, (2) metals such as iron, cobalt, nickel, or these metals and aluminum, cobalt, copper , Lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium, and alloys thereof, and (3) mixtures thereof. 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.

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 exemplary embodiment can 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, high compatibility with the binder resin is preferable, and known ones can be used. Specific examples of commercially available products include “Azisper PB821”, “Azisper PB822” (Ajinomoto Fine Techno) And “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.

The toner component liquid used in this embodiment contains a wax together with a binder resin and a colorant.
The wax is not particularly limited and can be appropriately selected from commonly used ones such as low molecular weight polyethylene, low molecular weight polypropylene, polyolefin wax, microcrystalline wax, paraffin wax, and sazol wax. Oxides of aliphatic hydrocarbon waxes such as aliphatic hydrocarbon waxes, polyethylene oxide waxes or block copolymers thereof, plant waxes such as candelilla wax, carnauba wax, wood wax, jojoba wax, beeswax, lanolin , Animal waxes such as whale wax, mineral waxes such as ozokerite, ceresin and petrolatum, waxes mainly composed of fatty acid esters such as montanic ester wax and castor wax, and fatty acid esters such as deoxidized carnauba wax. part Those deoxygenated all are and the like.

  The melting point of the wax is preferably 70 to 140 [° C.] and more preferably 70 to 120 [° C.] in order to balance the fixing property 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 embodiment, the temperature of the peak top of the maximum 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 embodiment 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.

  In the toner according to the exemplary embodiment, as other additives, protection of the latent image carrier and carrier, improvement of cleaning properties, adjustment of thermal characteristics / electrical characteristics / physical characteristics, resistance adjustment, softening point adjustment, improvement of fixing rate For purposes such as various types of metal soaps, fluorosurfactants, dioctyl phthalate, tin oxide, zinc oxide, carbon black, antimony oxide, etc. as conductivity imparting agents, inorganic fine powders such as titanium oxide, aluminum oxide, alumina, etc. A body etc. can be added as needed. 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 a functional group, and other organic materials for the purpose of controlling the amount of charge. It is also preferable to treat with a treating agent such as a silicon 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 silane coupling agents, silylating agents, silane coupling agents having a fluorinated alkyl group, organic titanate coupling agents, aluminum coupling agents, silicone oils, modified silicone oils, Etc. are preferable.

The primary particle diameter of the external additive is preferably 5 [nm] to 2 [[mu] m], 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].

[Example 1]
Hereinafter, an embodiment of the present invention (hereinafter referred to as “embodiment 1”) will be described.
The formulation of the toner component liquid used in Example 1 is shown below. Note that the droplet discharge conditions are as described in the above-described embodiment.
First, a carbon black dispersion as a colorant was prepared. 17 parts by mass of carbon black (RegaL400: 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 this 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 aggregates of 5 [μm] or more are completely obtained. The secondary dispersion removed in the above was prepared.

  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.] while stirring to dissolve the carnauba wax, and then the temperature of the liquid 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 is 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]) so that the maximum diameter is 1 [μm] or less. It was adjusted.

  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 mass of a polyester resin as a binder resin, 30 parts by mass of the colorant dispersion, 30 parts by mass of the wax dispersion, 840 parts by mass of ethyl acetate, and stirring for 10 minutes using a mixer having stirring blades, Evenly dispersed. Pigments and wax particles did not aggregate due to shock due to solvent dilution.

Next, conditions of the toner manufacturing apparatus used in Example 1 will be described. The configuration of the toner manufacturing apparatus is as described in the embodiment.
In the liquid column resonance droplet forming unit 310 of this embodiment, 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], N = 2 resonance mode, The first to fourth discharge holes 19 arranged along the longitudinal direction are arranged at the antinodes of the pressure standing wave in the N = 2 mode. The driving frequency was set to 340 [kHz] according to the liquid resonance frequency.

  In the dry collection unit 320 of this embodiment of FIG. 13, the inner diameter of the chamber 321 is φ400 [mm] and the height is 2000 [mm] and is fixed vertically, and the upper end and the lower end are narrowed. Shape. The diameter of the carrier air inlet at the upper end is φ50 [mm], and the diameter of the carrier air outlet at the lower end is φ50 [mm]. The liquid column resonance droplet forming unit 310 is disposed at the center of the chamber 321 in the horizontal direction at a height of 300 mm from the upper end in the chamber 321. The carrier airflow (downward airflow 323) was 10.0 [m / s] and 40 [° C] nitrogen. A cyclone collector was used as the solidified particle collecting means 325.

  The piezoelectric element driving circuit of Example 1 in FIG. 9 was used as the piezoelectric element driving circuit used in the toner manufacturing apparatus of this embodiment, and the oscilloscope 106 was controlled so that the peak value of the AC voltage was constant. The control time interval was 1 [second], and the allowable voltage range was controlled at ± 0.4 [V] with respect to the set voltage 8.0 [V].

Evaluation of the toner produced in Example 1 was performed as follows.
Using the toner production apparatus of Example 1 of FIG. 13, the produced toner component liquid 331 is discharged for 1 hour, and the droplets are dried and solidified in the chamber 321 to collect toner particles by a cyclone collector. Collected and stored in a toner storage container. The toner was removed from the toner storage container, and the toner was collected. Then, for each toner, the toner particle size distribution was measured using a flow type particle image analyzer (Sysmex Corporation FPIA-3000) under the following measurement conditions. The production and measurement of the toner as described above were repeated three times, and the average value was evaluated.

Measurement with a flow particle image analyzer (Flow Particle Image Analyzer) removes fine dust through a filter, and as a result, a measurement range (for example, an equivalent circle diameter of 0.60 [μm]) in 10 ⁻³ [cm ³ ] water. A few drops of a nonionic surfactant (preferably Contaminone N manufactured by Wako Pure Chemical Industries, Ltd.) is added to 10 [ml] of water having 20 or less particles having a particle size of 159.21 [μm] or less. Further, 5 [mg] of a measurement sample is added, and dispersion treatment is performed for 1 minute under the conditions of 20 [kHz] and 50 [W] / 10 [cm ³ ] using an ultrasonic dispersing device UH-50 manufactured by STM. Further, a 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 [pieces / 10 ⁻³ · cm ³ ] (for particles in the measurement equivalent circle diameter range) is 0 The particle size distribution of particles having an equivalent circle diameter of .60 [μm] or more and less than 159.21 [μm] is measured.

  The sample dispersion is passed through a flat and flat transparent flow cell (thickness: about 200 [μm]) flow path (spread along the flow direction). 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 about 1 minute, the equivalent circle diameter of 1200 or more particles can be measured, and the number based on the equivalent circle diameter distribution and the ratio (number%) of particles having a prescribed equivalent circle diameter 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 for one octave). In actual measurement, particles are measured in a range where the equivalent circle diameter is 0.60 [μm] or more and less than 159.21 [μm].

  In Example 1, as a result of this measurement, the average of the volume average particle diameter (Dv) of the obtained toner particles (average of three measurements; the same applies hereinafter) is 5.5 [μm], and the number average particle The average diameter (Dn) was 5.2 [μm], and the average Dv / Dn was 1.05. Furthermore, as a result of measuring the particle diameter after 1 hour has passed since the start of collection, the same volume average particle diameter (Dv) and number average particle diameter (Dn) as the above results were obtained.

[Example 2]
Next, another embodiment of the present invention (hereinafter referred to as “embodiment 2”) will be described.
In Example 2, the piezoelectric element driving circuit of FIG. 10 is used as the piezoelectric element driving circuit used in the toner manufacturing apparatus of the present embodiment, and the oscilloscope 117 is controlled so that the peak value of the AC voltage is constant. The toner was collected for 1 hour under the same conditions as in Example 1. The resulting toner particles have an average volume average particle size (Dv) of 5.5 [μm], an average number average particle size (Dn) of 5.1 [μm], and an average of Dv / Dn. Was 1.08. Furthermore, as a result of measuring the particle diameter after 1 hour has passed since the start of collection, the same volume average particle diameter (Dv) and number average particle diameter (Dn) as the above results were obtained.

Example 3
Next, still another embodiment of the present invention (hereinafter, this embodiment is referred to as “embodiment 3”) will be described.
In Example 3, the piezoelectric element driving circuit shown in FIG. 11 is used as the piezoelectric element driving circuit used in the toner manufacturing apparatus of the present embodiment, and the oscilloscope 127 is used to control the peak value of the AC voltage to be constant. The toner was collected for 1 hour under the same conditions as in Example 1. The resulting toner particles have an average volume average particle size (Dv) of 5.5 [μm], an average number average particle size (Dn) of 5.1 [μm], and an average of Dv / Dn. Was 1.08. Furthermore, as a result of measuring the particle diameter after 1 hour has passed since the start of collection, the same volume average particle diameter (Dv) and number average particle diameter (Dn) as the above results were obtained.

Example 4
Next, still another embodiment of the present invention (hereinafter referred to as “embodiment 4”) will be described.
In Example 4, the piezoelectric element driving circuit shown in FIG. 10 is used as the piezoelectric element driving circuit used in the toner manufacturing apparatus of this embodiment, and the voltage value is controlled to be constant by the voltmeter 116. Toner was collected for 1 hour under the same conditions as in Example 1. The resulting toner particles have an average volume average particle size (Dv) of 5.6 [μm], an average number average particle size (Dn) of 5.2 [μm], and an average of Dv / Dn. Was 1.08. Furthermore, as a result of measuring the particle diameter after 1 hour has passed since the start of collection, the same volume average particle diameter (Dv) and number average particle diameter (Dn) as the above results were obtained.

Example 5
Next, still another embodiment of the present invention (hereinafter referred to as “embodiment 5”) will be described.
In Example 5, the piezoelectric element driving circuit shown in FIG. 10 is used as the piezoelectric element driving circuit used in the toner manufacturing apparatus of the present embodiment, and the current value is controlled to be constant by the ammeter 115. Toner was collected for 1 hour under the same conditions as in Example 1. The resulting toner particles have an average volume average particle size (Dv) of 5.6 [μm], an average number average particle size (Dn) of 5.3 [μm], and an average of Dv / Dn. Was 1.06. Furthermore, as a result of measuring the particle diameter after 1 hour has passed since the start of collection, the same volume average particle diameter (Dv) and number average particle diameter (Dn) as the above results were obtained.

Example 6
Next, still another embodiment of the present invention (hereinafter, this embodiment is referred to as “embodiment 6”) will be described.
In Example 6, the piezoelectric element driving circuit shown in FIG. 11 is used as the piezoelectric element driving circuit used in the toner manufacturing apparatus of the present embodiment, and the voltmeter 126 is controlled so as to make the voltage value constant. Toner was collected for 1 hour under the same conditions as in Example 1. The resulting toner particles have an average volume average particle size (Dv) of 5.6 [μm], an average number average particle size (Dn) of 5.3 [μm], and an average of Dv / Dn. Was 1.06. Furthermore, as a result of measuring the particle diameter after 1 hour has passed since the start of collection, the same volume average particle diameter (Dv) and number average particle diameter (Dn) as the above results were obtained.

Example 7
Next, still another embodiment of the present invention (hereinafter referred to as “embodiment 7”) will be described.
In Example 7, the piezoelectric element driving circuit shown in FIG. 11 is used as the piezoelectric element driving circuit used in the toner manufacturing apparatus of the present embodiment, and the current value is controlled to be constant by the ammeter 125. Toner was collected for 1 hour under the same conditions as in Example 1. The resulting toner particles have an average volume average particle size (Dv) of 5.5 [μm], an average number average particle size (Dn) of 5.3 [μm], and an average of Dv / Dn. Was 1.04. Furthermore, as a result of measuring the particle diameter after 1 hour has passed since the start of collection, the same volume average particle diameter (Dv) and number average particle diameter (Dn) as the above results were obtained.

  As described above, also in the first to seventh embodiments, even after one hour has elapsed from the start of the discharge operation and after one hour has elapsed since the start of collection, droplet coalescence or splitting due to fluctuations in the discharge capacity Narrow toner particle size distribution similar to that in the initial stage was obtained.

[Comparative Example 1]
In Comparative Example 1, the piezoelectric element driving circuit of FIG. 11 is used as the piezoelectric element driving circuit used in the toner manufacturing apparatus of the present embodiment, and the stabilization control as in the present embodiment is not performed. The toner was collected for 1 hour under the same conditions. The resulting toner particles have an average volume average particle size (Dv) of 5.5 [μm], an average number average particle size (Dn) of 5.2 [μm], and an average of Dv / Dn. Was 1.05. Furthermore, as a result of measuring the particle diameter after 1 hour has passed since the start of collection, the average of the volume average particle diameter (Dv) of the toner particles is 4.8 [μm], and the average of the number average particle diameter (Dn). Was 4.2 [μm], and the average Dv / Dn was 1.14. In Comparative Example 1, it was found that the particle diameter collected with the passage of time decreased, and it became difficult to form a high-quality image after 1 hour. In this comparative example, the coalescence and breakage of the droplets due to the change in the discharge capability with time were caused, and the same narrow toner particle size distribution as in the initial stage could not be obtained.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
(Aspect 1)
The toner component liquid 14 such as the liquid in the liquid column resonance liquid chamber 18 such as the liquid chamber in which the discharge hole 19 is formed is vibrated through the vibration plate 22 by the piezoelectric element 101 as the vibration generating means. In a droplet discharge device that discharges toner component liquid 14 from 19 to form droplets, waveform generating means 102 as supply means for supplying voltage or current to the input side of piezoelectric element 101 as vibration generating means, and DC power supply 114 , 124, and ammeters 115 and 125 such as measuring means for measuring the voltage or current on the output side of the piezoelectric element 101, voltmeters 116 and 126, and oscilloscopes 106, 117, and 127, and the piezoelectric measured by the measuring means By supplying means so that the difference between the voltage measurement value or current measurement value on the output side of the element 101 and the preset target voltage value or target current value is small. Controlling the voltage or current supplied to the input side of the electric element.
According to this, as described in the above embodiment, the original electric power supplied to the input side of the piezoelectric element 101 due to the heat generated by the resistance of the wiring electrically connecting the piezoelectric element 101 and the supply means. A part is consumed, and the voltage or current supplied to the input side of the piezoelectric element 101 decreases. Furthermore, the voltage or current on the output side of the original piezoelectric element is reduced with respect to the voltage or current supplied to the input side of the piezoelectric element 101 by self-heating of the piezoelectric element 101. By measuring the voltage or current on the output side of the piezoelectric element 101, it is possible to detect a substantial voltage or current on the output side of the piezoelectric element 101 that is reduced by heat generation due to wiring resistance or self-heating of the piezoelectric element 101. . The voltage or voltage supplied to the input side of the piezoelectric element 101 by the supply means so that the voltage measurement value or current measurement value obtained by measuring the voltage or current on the output side of the piezoelectric element 101 is substantially equal to the target voltage value or target current value. Control the current. As a result, it is possible to cancel out the discharge capability that has decreased due to a substantial decrease in voltage or current. Therefore, stable droplet discharge can be performed.
(Aspect 2)
In (Aspect 1), the power measuring means is provided in a part of the wiring electrically connected to the piezoelectric element 101. According to this, as described in the above embodiment, it is possible to detect a substantial voltage or current on the input side of the piezoelectric element 101 that is reduced due to heat generated by the wiring resistance. If the voltage or current on the output side of the piezoelectric element 101 can be measured, the actual voltage measurement value or current measurement value on the input side of the piezoelectric element 101 reduced due to heat generated by the wiring resistance, and the measured piezoelectric element It is possible to detect a substantial voltage or current on the output side of the piezoelectric element reduced by self-heating of the piezoelectric element 101 from the voltage measurement value or current measurement value on the output side of 101.
(Aspect 3)
(Aspect 1) or (Aspect 2)
The frequency of the electric power supplied to the piezoelectric element 101 is in the range of 100 to 1000 [kHz]. According to this, as described in the above embodiment, the particles are ejected by high-frequency vibration and a narrow particle size distribution is obtained.
(Aspect 4)
In any one of (Aspect 1) to (Aspect 3), vibration is imparted to the liquid in the liquid column resonance liquid chamber in which the discharge hole is formed to form a standing wave by liquid column resonance, Liquid is ejected from the ejection holes formed in the region where the standing wave becomes an antinode to form droplets. According to this, as described in the above embodiment, continuous and stable ejection is possible, and a narrow particle size distribution is obtained.
(Aspect 5)
Liquid column resonance droplet forming unit 310 as droplet discharge means for discharging a particle component-containing liquid containing particle components from the discharge holes, and solidification drying for solidifying and drying the droplets of the particle component-containing liquid discharged from the discharge holes In the toner manufacturing apparatus 300 of the particle manufacturing apparatus including the dry collection unit 320 as a means, any one of the droplet discharge devices of (Aspect 1) to (Aspect 4) is used as the droplet discharge means. According to this, as described in the above embodiment, it is possible to manufacture particles such as toner having a uniform particle diameter.

DESCRIPTION OF SYMBOLS 100 Piezoelectric element drive circuit 101 Piezoelectric element 102 Waveform generation means 103 Preamplifier 104 Main up 105 Resistance 106 Oscilloscope 110 Oscillator 111 FET drive circuit 112 High side FET
113 Low-side FET
114 DC power supply 115 Ammeter 116 Voltmeter 117 Oscilloscope 120 Signal generation circuit 121 Charge / discharge pulse 122 Voltage amplification circuit 123 NPN transistor 124 PNP transistor 125 Ammeter 126 Voltmeter 127 Oscilloscope 201 Set voltage value 202 Comparison adjustment means 203 Vibration generation means 204 Voltage value 205 Voltage measurement means 211 Set current value 212 Comparison adjustment means 213 Vibration generation means 214 Current value 215 Current measurement means 221 Installed power value 222 Comparison adjustment means 223 Vibration generation means 224 Voltage value / current value 225 Voltage measurement means / current measurement Means 300 Toner production apparatus 310 Liquid column resonance droplet forming unit 320 Dry collection unit 321 Chamber 322 Conveying air flow inlet 323 Downstream air 324 Collection outlet 325 Solidified particle collecting means 326 Drying hand 330 toner component replenishment unit 331 toner component liquid 332 toner component liquid tank 333 toner component liquid supply passage 334 liquid circulating pump 335 fluid return pipe

Japanese Patent No. 3786034 Japanese Patent No. 3786035 JP-A-57-201248 JP 2011-212668 A

The present invention relates to a droplet discharge method for discharging liquid from discharge holes into droplets, and a particle manufacturing method such as a toner manufacturing method using the droplet discharge method .

The present invention has been made in view of the above-described problems, and an object of the present invention is to suppress a substantial decrease in voltage or current while vibrating the vibration generating means at a high frequency and to stabilize the discharge capacity. It is an object of the present invention to provide a droplet discharge method that can be used.

In order to achieve the above object, the invention according to claim 1 is directed to ejecting the liquid from the ejection hole by applying vibration to the liquid in the liquid chamber in which the ejection hole is formed through the vibration plate by the vibration generating means. in a droplet discharge method for Te droplets of, along with supplying a voltage or current at the input side of the vibration generating means performs measurement of the measurement values of the output side of the voltage or current of said vibration generating means, measurement before Symbol meter has been a voltage measurement or current measurement values of the output side of the vibration generating means, so that the difference between the goal voltage value or target current value becomes smaller, the voltage supplied to the input side of the front Symbol vibration generating means Alternatively, the current is controlled.

Claims (5)

In a liquid droplet ejection apparatus that applies vibration to a liquid in a liquid chamber in which a discharge hole is formed via a vibration plate by a vibration generation unit to discharge the liquid from the discharge hole to form droplets.
Supply means for supplying voltage or current to the input side of the vibration generating means;
Measuring means for measuring the voltage or current on the output side of the vibration generating means,
The vibration by the supply means so that a difference between a voltage measurement value or current measurement value on the output side of the vibration generation means measured by the measurement means and a preset target voltage value or target current value becomes small. A droplet discharge device that controls the voltage or the current supplied to the input side of the generating means. The droplet discharge device according to claim 1,
The liquid droplet ejection apparatus, wherein the measuring unit is provided in a part of a wiring electrically connected to the vibration generating unit. The liquid droplet ejection apparatus according to claim 1 or 2,
The droplet discharge device according to claim 1, wherein a frequency of electric power supplied to the vibration generating means is in a range of 100 to 1000 [kHz]. In the droplet discharge device according to any one of claims 1 to 3,
A vibration is applied to the liquid in the liquid column resonance liquid chamber in which the discharge hole is formed to form a standing wave by liquid column resonance, and the liquid is formed in a region that becomes an antinode of the standing wave. A liquid droplet ejection apparatus, wherein the liquid is ejected from the ejection holes to form liquid droplets. Droplet discharge means for discharging the particle component-containing liquid containing the particle components from the discharge holes;
Solidifying and drying means for solidifying and drying droplets of the particle component-containing liquid discharged from the discharge holes, and a particle manufacturing apparatus comprising:
5. A particle manufacturing apparatus using the droplet discharge device according to claim 1 as the droplet discharge means.