JP2722407B2 - Powder transfer method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for conveying powder.

[Prior Art] Conventionally, the most common technique for conveying powder is a method using a screw, which is used for all powder conveying means. In this method, for example, powder in a pipe is conveyed by rotating a screw provided inside the pipe.

[Problems to be Solved by the Invention] However, in the above-described conventional example, since the screw in the pipe must be rotated by the motor, there is a problem that power consumption is large and the rotation noise is relatively large.

The configuration also requires a relatively complicated member such as a screw and a motor, so that the space is increased and the cost is increased.

Also, if the gap between the pipe inner wall and the screw is large, the transfer efficiency will decrease, and if the gap between the screw and the pipe inner wall is small, the transfer efficiency will increase, but the rotational torque of the screw will increase due to the friction between the screw and the pipe inner wall. It also had the problem of becoming

Further, the powder may be deteriorated, broken, or melted by frictional heat due to friction between the inner wall and the screw. In addition, since powder is generally easily charged, the powder is often charged during transport and adheres to the screw in many cases. In severe cases, transport failure occurs.

An object of the present invention is to solve the above-mentioned problems and to provide a method for conveying a powder band with low power consumption, low noise, and good conveyance efficiency.

[Means for Solving the Problems] According to the present invention, the object is to provide vibration generating means at a plurality of longitudinal positions of a tubular or trough-shaped powder transporting member for transporting powder in a longitudinal direction, Vibration is applied in the radial direction of the powder conveying member by the vibration generating means to generate a traveling wave in the longitudinal direction by the vibration, and the powder conveying member between the vibration generating means is connected via a vibration absorbing member. By suppressing the interference of the traveling wave,
It is achieved by conveying powder in a predetermined direction within the powder conveying member.

[Operation] According to the present invention, vibration is generated in the radial direction of the powder conveying member by the vibration generating means arranged at a plurality of positions in the longitudinal direction of the powder conveying member. Then, traveling waves are generated in both longitudinal directions around each vibration generating means. However, a vibration absorbing member is attached near one of the vibration generating means, and the generation of a backward traveling wave traveling in the direction in which the vibration absorbing member is attached is suppressed to prevent interference between traveling waves. Therefore, the traveling wave generated from each vibration generating means only travels in the direction opposite to the direction in which the vibration absorbing member is attached, and the traveling waves are combined. Thus, the powder in the powder transport member is transported in a direction opposite to the direction of the synthesized traveling wave.

Embodiments First to fourth embodiments of the present invention will be described with reference to the accompanying drawings.

<First Embodiment> First, a first embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention. This device is a powder conveying device using the present invention.

In FIG. 1, 1 is a hopper for supplying powder, and 2 is an acrylic hollow pipe as a tubular powder member. The hollow pipe 2 has an outer diameter of 15 mm and an inner diameter of 10 mm and is elongated in the longitudinal direction.

An ultrasonic vibration generating piezoelectric element 3 as vibration generating means is disposed at regular intervals in the longitudinal direction of the hollow pipe 2, and an AC voltage is applied by an AC power supply 4.

The piezoelectric element 3 has an outer diameter of 30 mm and an inner diameter of 30 mm as shown in FIG.
This type sandwiches ceramic PZT with a thickness of 15mm and a thickness of 2mm between electrodes from both sides.

By applying a voltage between the electrodes, as shown in FIG. 3, expansion and contraction vibrations are excited in the inner and outer diameter directions, that is, in the r direction by the stretching force of the ceramic, and the vibrations are transmitted to the hollow pipe 2 as traveling waves. . Due to the traveling wave generated by the piezoelectric element 3, the powder in the hollow pipe is transported in a direction (A in FIG. 1) opposite to the direction of the traveling wave. In the above embodiment, the peak-to-peak voltage is 100 V, and the frequency is 50.
KHz AC voltage is applied. This is a value calculated from the resonance mode based on the shape of the piezoelectric element, and the resonance frequency can be changed by changing the thickness and the shape of the piezoelectric element. In this embodiment, only one piezoelectric element is used. However, as shown in FIG. 4, a large number of sandwich types (multi-layer type) can further increase the amount of excitation vibration and the traveling wave transmitted to the hollow pipe. Therefore, the powder conveying force also increases. Further, as shown in FIG. 5, an electrode may be provided on the circumference of the piezoelectric element. Furthermore, various vibration modes can be obtained by subdividing the electrodes of the piezoelectric element and changing the polarity of the applied voltage. Specifically, the electrode arrangement shown in FIG.
It is possible to excite a uniaxially symmetric vibration called a ((1,1)) mode shown in the figure.

Further, when the electrode division is subdivided as shown in FIG. 8, a central axis parallel vibration called ((2, 1)) mode can be excited as shown in FIG. Further, by rotating the phase of the AC voltage applied to these electrodes by 90 °, a rotation mode of the vibration is also possible.

In this manner, many vibration modes can be excited by subdividing the electrode division and shifting the phase of the voltage applied to each electrode. By utilizing these various modes, it is possible to select the optimal excitation mode that matches the characteristics of various powders,
A sufficient conveying force can be obtained according to each powder.

This is because the powder has various masses, specific gravities, slip properties, tackiness, and charging properties, and even if the hollow pipe is the same, the powder transportability strongly depends on the characteristics of the powder itself.

The same can be said for the case where the material, surface properties and chargeability of the hollow pipe change.

However, even if a plurality of piezoelectric elements are connected to a long hollow pipe and powder is conveyed for a long distance, the vibration generated by the piezoelectric elements always produces a symmetrical traveling wave around the piezoelectric elements, and the vibration is generated in one direction. Cannot be transferred. FIG. 16 (B) is a schematic view of each traveling wave generated by a plurality of piezoelectric elements in the same long hollow pipe. And the second
FIG. 16 (C) shows a schematic diagram of the vibration of the traveling wave excited in the hollow pipe after the respective traveling waves are synthesized, and the magnitude and direction of the powder conveying force by the traveling wave.

As is clear from these figures, the powder transfer force acts in the direction of each piezoelectric element, so that powder transfer in one direction becomes impossible,
As shown in FIG. 16 (A), the result is that the powder stays in the form of a branch near each voltage element.

Therefore, in the present invention, as shown in FIG. 1, the hollow pipe between the piezoelectric elements is divided so that the traveling wave generated by the piezoelectric element does not interfere with the traveling wave generated by another piezoelectric element.

Further, in order to minimize the effect of the backward traveling wave generated by itself, a hollow pipe near the piezoelectric element where the backward traveling wave is generated is cut, and a member that absorbs vibration and does not transmit, that is, a so-called vibration absorbing member is interposed. FIG. 10 (B) is a schematic view of each traveling wave generated by the piezoelectric element to explain the function of the vibration absorbing member.

As shown in FIG. 10, the traveling wave transmitted through the hollow pipe 2 is attenuated by the vibration absorbing member 5, and the traveling wave is not transmitted to the adjacent hollow pipe 2.

FIG. 10 (C) shows the vibration of the traveling wave excited in the hollow pipe 2 after each traveling wave is synthesized.

By cutting the hollow pipe 2 in which the backward traveling wave is generated, and by interposing a vibration absorbing member therebetween, the influence of the backward traveling wave can be reduced, and as shown in FIG. It is possible to have size and directionality.

As is clear from this, the effective powder conveying force acts in a certain direction, and the powder is strongly conveyed in the direction of arrow A as shown in FIG. 10 (A). In other words, by shifting the position of the vibration absorbing member from an intermediate point between adjacent piezoelectric elements, the powder can be transported in the direction opposite to the shifting direction, and the transport force increases as the distance from the piezoelectric element increases.

Further, if the vibration width at the end of the hollow pipe 2 which is in contact with the vibration absorbing member 5 is not attenuated to half or less of the vibration width at the piezoelectric element, the influence of the reflected wave at the end increases, and The attenuation of the wave carrier force is undesirably large.

Then, as shown in FIG. 11, the vibration-absorbing member 5 was connected to a hollow acrylic pipe by a vibration-proof rubber (NBR) 5B and a silicone-based adhesive 5A.

As a result, the powder could be smoothly transported over a long distance of 2 m without being clogged with powder. When a one-component magnetic toner having an average particle diameter of 12 μm was used as the powder, the powder conveyance force was 500 g / min.

Further, it was found that the same conveying force as that of the magnetic toner can be obtained by using a powder having an average particle diameter of glass beads of 60 μm, an average particle diameter of ferrite carrier of 60 μm, and a non-magnetic toner having an average particle diameter of 8 μm or a mixture thereof. .

At this time, the amount of powder conveyed changed in proportion to the voltage applied to the piezoelectric element, and it became possible to control the amount of powder conveyed.

Incidentally, in this embodiment, the same phase and the same AC voltage (peak body peak voltage 100 V, frequency 50 KHz) were continuously applied, but the piezoelectric elements became independent events by the vibration absorbing member, and the Phase, application time,
Even if the applied voltage is changed, the powder conveying force of the voltage element can be controlled without affecting other voltage elements.

In addition, the material used for the powder conveying member has a relatively large damping rate, and the amplitude of the excitation generated at the end portion is relatively large.
It was found that if the ratio was less than 1/2, the influence of the reflected wave was small and the carrying capacity was excellent. According to experiments, acrylic, nylon POM (polyacetal) ABS polypropylene, polystyrene and the like are suitable.

As the vibration absorbing member, NBR, urethane rubber, Si rubber EKDM, gel resin, Si rubber adhesive, etc. are optimal,
By making the rubber hardness small, almost 100% of traveling wave vibration can be absorbed. According to experiments, if the amplitude of the traveling wave propagating through the vibration absorbing member is attenuated to half or less when the vibration absorption rate is 50%, the traveling wave generated from the adjacent hollow pipe and the thick electric element is hardly affected. It was also found that the powder was smoothly transferred.

As described above, since there is no conveying member such as a screw inside the hollow pipe, the powder can be efficiently conveyed without deterioration, destruction, melting, or the like.

In this embodiment, an acrylic hollow pipe is used, but in this configuration, the amplitude of vibration given to a part of the acrylic hollow pipe as a powder conveying member is attenuated by absorbing the vibration of the member, that is, the acrylic hollow pipe itself. Have been. The present invention is configured such that the excited amplitude of the powder conveying member is attenuated at the end in the conveying direction, generates a traveling wave, and conveys the powder. However, it is effective and can be realized simply and inexpensively.

In addition to using a material with a large attenuation, the material may be a material with a small attenuation, such as attaching a material with a large attenuation to a part of a metal pipe, or forming a groove in the metal pipe itself to increase the attenuation. Can be

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIG.
The same parts as those in the first embodiment are denoted by the same reference numerals, and the description is omitted.

This embodiment is different from the first embodiment in that the hollow pipes are connected by covering with a rubber tube 5 as shown in FIG. By using this method, not only rubber but also
Soft resins such as nylon, polypropylene, vinyl chloride, PTFE, and PFA can be used.

According to this embodiment, the same effects as those of the first embodiment can be obtained.

Third Embodiment Next, a third embodiment of the present invention will be described with reference to FIGS. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description is omitted.

This embodiment is different from the first embodiment in that a groove-shaped conveying member 2 is used instead of the hollow pipe 2 as shown in FIG. Also in this embodiment, acrylic is applied to the conveying member.

The transport principle is the same as that of the first embodiment, and a voltage is applied to the piezoelectric elements 3 from the AC power supply 4 and the vibration preventing member 5 is used so that the traveling waves of the respective piezoelectric elements do not interfere with each other. To be transported.

This has the advantage that powder can be easily supplied from the groove opening because the upper part is opened instead of the hollow pipe.

The same effect can be obtained even if the powder conveying member 2 is formed in a gutter shape as shown in FIG.

Fourth Embodiment Next, a fourth embodiment of the present invention will be described with reference to FIG. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description is omitted.

This embodiment is different from the first embodiment in that the piezoelectric element 3 is fixed to the lower part of the hollow pipe 2 as shown in FIG. This is a method in which a plate-like piezoelectric element such as a laminated piezoelectric element is vibrated and a part of a hollow pipe is hit with a piezoelectric element to generate a traveling wave from a part and to convey the powder, as in the other embodiments. Sufficient conveyance force is generated. Further, although the vibration preventing member 5 is inserted in a direction perpendicular to the axis of the hollow pipe, an angle may be provided with respect to the axis of the hollow pipe, or the axis may be asymmetric.
When a traveling wave is generated from a part of the cylindrical pipe, the shape of the vibration preventing member 5 may be changed in consideration of the influence of the reflected wave.

With such a configuration, the powder can be transported simply and compactly, which is advantageous for pipe replacement and cost.

[Effects of the Invention] As described above, according to the present invention, vibration is generated in the radial direction by the vibration generating means to the powder conveying member connected by the vibration absorbing member to generate a traveling wave. The powder can be efficiently transported over a long distance with energy. Further, the powder can be conveyed quietly and smoothly without deterioration, breakage or melting.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of a first embodiment of the apparatus of the present invention, FIG. 2 is a perspective view showing a schematic configuration of a vibration generating means of the apparatus of FIG. 1, and FIG. FIG. 4 is a view showing a change in the outer wall of the body conveying member, FIG. 4 is a perspective view showing a schematic configuration when the means of FIG. 2 are stacked, and FIG. 5 is provided with electrodes on the circumferential portion of the means of FIG. FIG. 6 is a perspective view showing a schematic configuration in the case, FIG. 6 is a view showing an electrode arrangement in the ((1,1)) mode of the means of FIG. 2, and FIG. FIG. 8 is a view showing the change of the outer wall of the member, FIG. 8 is a view showing the electrode arrangement in the ((2, 1)) mode of the means of FIG. 2, and FIG.
FIG. 10 (A) is a diagram showing a change in the outer wall of the powder conveying member in the case of the arrangement shown in FIG. 10, FIG. 10 (A) is a diagram showing the state of powder inside the powder conveying member of the FIG. 1 apparatus, and FIG. 10 (B). FIG. 10 is a diagram illustrating a traveling wave generated in a powder conveying member in the apparatus of FIG. 1, FIG. 10 (C) is a diagram illustrating a traveling wave after synthesizing each traveling wave of FIG. 10 (B), FIG. 11 is a view showing a schematic configuration of a vibration absorbing member of the apparatus of FIG. 1, FIG. 12 is a view showing a schematic configuration of a second embodiment apparatus of the present invention, and FIG. 13 is a third embodiment apparatus of the present invention. FIG. 14 is a diagram showing a schematic configuration of the apparatus, FIG. 14 is a view showing a case where the powder conveying member of the apparatus of FIG. 13 is formed in a gutter shape, FIG. 15 is a view showing a schematic configuration of a fourth embodiment apparatus of the present invention, Fig. 16 (A)
FIG. 16 is a view showing a state of powder inside the powder conveying member when the vibration absorbing member is not attached to the apparatus in FIG. 1, and FIG. 16 (B) shows a progress generated in the powder conveying member in the apparatus in FIG. FIG. 16 (C) is a diagram illustrating a traveling wave after the traveling waves of FIG. 16 (B) are combined. 2 ... powder conveying member (hollow pipe) 3 ... vibration generating means (piezoelectric element) 5 ... vibration absorbing member

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroaki Tsuchiya 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Nobuyuki Ito 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-B-45-30423 (JP, B1)

Claims (6)

(57) [Claims] 1. A vibration generating means is provided at a plurality of longitudinal positions of a tubular or trough-shaped powder conveying member for conveying powder in a longitudinal direction, and the vibration generating means moves the powder in a radial direction of the powder conveying member. Vibration is applied, and the vibration generates a traveling wave in the longitudinal direction. By connecting the powder conveying member between the vibration generating means via a vibration absorbing member, interference of the traveling wave is suppressed, and the powder conveying member A powder conveying method for conveying powder in a predetermined direction in the inside. 2. The powder conveying method according to claim 1, wherein the traveling wave is attenuated in a powder conveying direction of the powder conveying member. 3. The powder conveying method according to claim 1, wherein the vibration generating means uses a piezoelectric element. 4. The powder conveying method according to claim 1, wherein a hollow pipe is used as the powder conveying member. 5. The powder conveying method according to claim 1, wherein the vibration absorbing member is configured to attenuate the amplitude of the traveling wave. 6. The powder conveying method according to claim 1, wherein the vibration absorbing member uses a resin or a rubber-based adhesive.