JP6327919B2 - Airflow classifier - Google Patents

Description

  The present invention relates to an apparatus for efficiently obtaining fine powder in a predetermined micron particle diameter region from a powder raw material by airflow classification.

  Examples of conventional airflow classifiers include those shown in Patent Document 1 below. As shown in this document, for example, when manufacturing powder such as toner for copying machines, toner raw materials in which particles of various particle sizes are mixed are jetted along the airflow contact surface of the Coanda block. 2. Description of the Related Art An airflow classifier that classifies toner materials according to particle diameter by utilizing a difference in scattering and descending paths that vary depending on the particle diameter, which is caused by the so-called “Coanda effect”, is widely used.

JP-A-8-238457

However, in the conventional airflow classifier using the Coanda effect, the classification performance when removing coarse powder (powder having a particle diameter of 10 μm or more) from the powder raw material (classified raw material) is not always sufficient. Although various devices have been made to improve the classification performance, the apparatus configuration has become complicated for that purpose, and there remains room for improvement.
An object of the present invention is to improve the classification performance when removing coarse powder from a powder raw material (classified raw material) with a simple configuration.

The first characteristic configuration according to the airflow classifier of the present invention includes: a classification area in which a classification raw material is classified; an inlet passage for allowing a gas to flow into the classification area; and a classification raw material from the side to the classification area. A raw material supply nozzle for injecting; a lower block disposed adjacent to the lower side of the raw material supply nozzle; and a discharge passage for discharging the classified raw material classified from the classification region together with the gas, A part of the gas flowing through the upper part of the raw material supply nozzle flows into the classification region along the gas injection direction from the rear of the raw material supply nozzle, and the discharge passage includes at least a fine powder discharge passage and a coarse powder discharge. A gas contact surface of the lower block extending downward at an acute angle from the tip of the raw material supply nozzle as a starting point. The fine powder discharge flow Constitutes a part of the gas flowing out of the classification region to the fine powder discharge passage in the vicinity of the distal end of the material feed nozzle lies in that is configured to flow downward.

[Action and effect]
As in this configuration, the gas flowing into the classification region from the rear of the raw material supply nozzle along the gas injection direction is applied to the classified raw material injected from the raw material supply nozzle, and the fine powder discharge flow A part of the path is constituted by the gas contact surface of the lower block extending downward at an acute angle starting from the tip of the raw material supply nozzle, and the gas flowing out from the classification area to the fine powder discharge channel is at the tip of the raw material supply nozzle. By configuring it to flow downward in the vicinity, it is possible to remove coarse powder from a powder raw material (classified raw material) compared to a conventional airflow classifier, without using the Coanda effect of a conventional Coanda block. Classification performance can be improved.
In addition, according to this configuration, unlike the conventional airflow classifier that uses a Coanda block, it is not necessary to make any special device to improve the classification performance. Costs can also be reduced.

  The second characteristic configuration is that the fine powder discharge channel is configured such that gas flows in a direction opposite to the gas injection direction of the raw material supply nozzle along the gas contact surface of the lower block. is there.

[Action and effect]
According to this configuration, the gas is configured to flow along the gas contact surface of the lower block in the direction opposite to the gas injection direction of the raw material supply nozzle. It means that the flow path to the flow path is bent sharply with a large curvature. By adopting such a configuration, it becomes difficult for the coarse powder to move to the fine powder discharge flow path, and the classification performance can be further enhanced.

  In the third characteristic configuration, a plurality of rectifying plates are provided in the inlet passages in different directions, and the flow angle of the gas into the classification region with respect to the gas injection direction of the raw material supply nozzle is determined by the rectifying plates. It is in the point which is comprised so that it may become large, so that it is far from the injection nozzle of a supply nozzle.

[Action and effect]
As in this configuration, by providing a plurality of rectifying plates in different directions so that the inflow angle of the gas into the classification region with respect to the gas injection direction of the raw material supply nozzle increases as the distance from the injection port of the raw material supply nozzle increases. In addition, the gas flow in the inlet air flow channel changes continuously, and the gas can easily flow smoothly to the classification region, thereby further improving the classification performance.

  In the fourth feature configuration, the plurality of rectifying plates are provided integrally with the disk member, and the disk member is attached to be rotatable around an axis, so that the inclination angles of the plurality of rectifying plates can be adjusted and set simultaneously. It is in a certain point.

[Action and effect]
According to this configuration, the user can simultaneously change the inclination angles of the plurality of current plates by rotating the disk member about the axis. That is, the user can easily change the flow direction of the gas in the intake air flow path to the direction intended by the user simply by rotating the disk member, and thereby the flow of the gas supplied to the classification area can be changed. It becomes possible to adjust.

  In the fifth characteristic configuration, the fine powder discharge channel and the coarse powder discharge channel are partitioned by a classification edge, and a distance between the tip of the classification edge and the tip of the raw material supply nozzle can be changed. Thus, the installation position of the classification edge can be changed.

[Action and effect]
According to this configuration, it is possible to adjust the width of the fine powder discharge channel by changing the distance between the tip of the classification edge and the tip of the raw material supply nozzle, thereby further improving the classification performance. it can.

  A sixth characteristic configuration is that the classification edge is attached so as to be movable in a horizontal direction with respect to a gas injection direction of the raw material supply nozzle.

[Action and effect]
As in this configuration, if the classification edge can be moved and adjusted in the horizontal direction with respect to the gas injection direction of the raw material supply nozzle, the width of each of the fine powder discharge passage and the coarse powder discharge passage can be adjusted accurately and reliably. Since it can be performed easily, it can be classified with high accuracy according to the size of the particles to be separated.

  A seventh characteristic configuration is that a tip of the classification edge is formed by an inclined surface constituting a part of the coarse powder discharge flow path and a curved surface constituting a part of the fine powder discharge flow path.

[Action and effect]
Like this structure, the front-end | tip of a classification edge can be comprised in a sharper shape by combining an inclined surface and a curved surface. Therefore, even if the classification edge is moved in the horizontal direction, the shapes of the fine powder discharge channel and the coarse powder discharge channel are not greatly changed, and classification can be performed with higher accuracy.

The eighth characteristic configuration is that the gas contact surface of the lower block includes a curved surface or a flat surface extending downward from the tip of the raw material supply nozzle.

[Action and effect]
According to this configuration, the gas contact surface of the lower block extending downward at an acute angle starting from the tip of the raw material supply nozzle can be configured in a very simple shape.

  The ninth characteristic configuration is that the discharge flow path further includes a coarse particle discharge flow path, and the coarse particle discharge flow path has an inflow port disposed opposite to the injection port of the raw material supply nozzle.

[Action and effect]
According to this configuration, when coarse particles having a particle diameter of several tens to several thousand μm are included in the powder raw material, the coarse particles that are jetted from the raw material supply nozzle and fly straightly are discharged from the inlet into the coarse particle discharge flow. Flows into the road. Therefore, the injected coarse particles do not collide with the wall in the apparatus and bounce off, and there is no possibility that the coarse particles are mixed into the fine powder discharge channel.

It is a figure which shows typically the whole classification system structure provided with the airflow type | formula classification apparatus of this invention. It is a figure which shows typically the structure of the airflow type classifier (1st Embodiment) of this invention. It is a disassembled perspective view which shows the attachment structure of a baffle plate typically. It is the figure which compared the structure of the airflow type classifier (solid line) of this invention with the structure of the conventional airflow type classifier (dashed line). It is a figure which shows typically the structure of the airflow type classifier (2nd Embodiment) of this invention. It is the figure which compared the classification performance by the airflow type classification apparatus (1st Embodiment) of this invention, and the classification performance by the conventional airflow type classification apparatus.

Hereinafter, embodiments of the airflow classifier of the present invention will be described.
[First Embodiment]
[1] Classification System As shown in FIG. 1, the classification system 1 according to the present embodiment includes a raw material feeder 2, a vibration feeder 3, an ejector 4, an air pump 5, an airflow classifier 10, and a cyclone 6 for collecting fine powder. , A coarse powder collecting cyclone 7, a dust collector 8, a blower 9 and the like.

  The powder raw material (classified raw material) sent from the raw material feeder 2 is sent to the ejector 4 by the vibration feeder 3 by a certain amount. Compressed air is supplied to the ejector 4 via an air pump 5, whereby a material to be classified such as toner is uniformly dispersed, and the airflow classifier 10 is supplied via a material supply nozzle 11. Be blown into.

  The powder raw material blown into the airflow classifier 10 is classified into a two-stage particle group of fine powder and coarse powder in the airflow classifier 10, and the fine powder is collected through the fine powder suction pipe 38. The coarse powder is collected in the collecting cyclone 6 and the coarse powder is collected in the coarse powder collecting cyclone 7 through the coarse powder suction pipe 39. Note that one or both of the fine powder collecting cyclone 6 and the coarse powder collecting cyclone 7 may be replaced with a dust collector such as a bag filter. However, when both are replaced with a dust collector, the dust collector 8 becomes unnecessary.

[2] Powder raw material (classified raw material) As a powder raw material applicable to the airflow classifier 10 of the present invention, for example, a fine powdery toner used for coloring paper in a copying machine or a laser printer Although a raw material is mentioned, it is not limited to these. In the present specification, a powder having a particle diameter of less than 10 μm contained in the powder material is defined as “fine powder”, and a powder having a particle diameter of 10 μm or more contained in the powder material is defined as “coarse powder”. Further, among the coarse powders contained in the powder raw material, a powder that is particularly large and has a particle diameter of several tens to several thousand μm is defined as “coarse particles”.

[3] Airflow classifier As shown in FIG. 2, the airflow classifier 10 of the present invention includes a raw material supply nozzle 11, a coarse powder side block 12, a raw material supply side block 13, a lower side block 14, a classification edge 15, The classification edge block 16 and the first to third rectifying plates 21, 22 and 23 are provided.

(Raw material supply nozzle)
The raw material supply nozzle 11 is supported from below by a lower block 14 adjacently disposed below the raw material supply nozzle 11, and is fitted between the raw material supply nozzle 13 disposed on the upper side and the lower block 14. Fixed. The raw material supply nozzle 11 has an injection port that opens to the classification region 34 at the tip thereof, and the material to be classified is injected laterally from the injection port of the raw material supply nozzle 11 to the classification region 34.

(Coarse powder side block)
The coarse powder side block 12 is disposed on the side opposite to the raw material supply nozzle 11. The coarse powder side block 12 has a first inclined surface 12a that is inclined so as to be closer to the raw material supply nozzle 11 as it goes downward, and a second inclined surface 12b that is inclined so as to be farther from the raw material supply nozzle 11 as it is downward. A vertical surface 12c extending in the vertical direction is connected in this order.

(Raw material supply side block)
The raw material supply side block 13 includes a first inclined surface 13a that is inclined so as to approach the coarse powder side block 12 as it goes downward, a curved surface 13b that forms a gently curved surface, and a lower surface of the coarse powder side block 12 from the lower end of the curved surface. A second inclined surface 13c extending in the lateral direction while being slightly inclined downward is provided in this order.

(Lower block)
The lower block 14 is provided with a lower surface 14a (gas contact surface) extending in the lateral direction after being curved downward so as not to protrude from the tip of the raw material supply nozzle 11 to the classification region 34 side. The shape of the lower surface 14a of the lower block 14 is not limited to this configuration, Additional example, constituted by linearly extending downward plane with an acute angle tip of the raw material supply nozzle 11 as a starting point Also good.

That is, the shape of the lower surface 14a of the lower block 14 may be a configuration that extends downward with an acute angle starting from the tip of the raw material supply nozzle 11, and the acute angle referred to here is that the lower surface 14a of the lower block 14 is Regardless of the curved surface or flat surface, the shape does not protrude from the tip of the raw material supply nozzle 11 to the classification region 34 side, or the tip of the raw material supply nozzle 11 is slightly chamfered to the classification region 34 side. It is meant to include a shape that slightly protrudes.

(Classified edge block)
The classification edge block 16 is disposed below the lower block 14. The classification edge block 16 is provided with a side surface 16a extending in the vertical direction, an upper surface 16b extending in the horizontal direction, a through space 16c penetrating in the vertical direction, and a through hole (not shown) that leads from the lateral outer surface to the through space 16c. An edge portion of the classification edge 15 is installed on the upper surface 16b. The knob member 17 is attached to the classification edge block 16 so as to be rotatable around the axis of the shaft portion 17a. The tip portion of the shaft portion 17a of the knob member 17 reaches the through space 16c through a through hole (not shown) of the classification edge block 16, and is connected to a protruding portion 15d of the classification edge 15 described later.

(Classification edge)
The classification edge 15 includes an inclined surface 15a constituting a part of the coarse powder discharge passage 37, a curved surface 15b constituting a part of the fine powder discharge passage 36, a bottom surface 15c, and a protruding portion 15d extending in the vertical direction from the bottom surface 15c, And the latching | locking part 15e provided in the front-end | tip of the protrusion part 15d is comprised. The edge portion of the classification edge 15 is a portion having a mountain-like longitudinal cross-sectional shape including an inclined surface 15a, a curved surface 15b, and a bottom surface 15c, and the edge portion has a sharp tip due to the inclined surface 15a and the curved surface 15b. Is formed.

  The classification edge 15 has its protruding portion 15d penetrating through the through space 16c of the classification edge block 16, and a locking portion 15e is provided at the tip of the protruding portion 15d slightly protruding from the lower opening of the through space 16c. As a result, the locking portion 15e is locked to the peripheral portion of the lower opening of the through space 16c, and the classification edge 15 is installed in a state in which the classification edge block 16 is prevented from coming off from the classification edge block 16. The upper opening of the through space 16 c is closed by the bottom surface 15 c of the classification edge 15.

  A female screw portion (not shown) is formed in the protruding portion 15 d of the classification edge 15, and a male screw portion formed at the tip portion of the knob member 17 is screwed into the female screw portion. When the knob member 17 is rotated around its axis, the protruding portion 15 d of the classification edge 15 moves along the male screw portion of the knob member 17. That is, the classifying edge 15 is configured to be moved in either the right or left direction on the upper surface 16b of the classifying edge block 16 by rotating the knob member 17, so that the installation position can be changed.

  In the present embodiment, the classification edge 15 is moved until the protruding portion 15d comes into contact with the right side wall of the through space 16c when moving in the right direction, and the protruding portion 15d is moved to the left side of the through space 16c when moving in the left direction. It can be moved until it abuts against the wall. During the movement of the classification edge 15, the upper opening of the through space 16c remains blocked by the bottom surface 15c of the edge portion. Further, as shown in FIG. 2, when the protruding portion 15d of the classification edge 15 is at an intermediate position in the horizontal direction in the through space 16c, the inclined surface 15a of the classification edge 15 and the side surface 16a of the classification edge block 16 are It becomes a substantially flush state.

  The classification edge 15 in the present embodiment is attached so as to be movable and adjustable in the horizontal direction with respect to the gas injection direction S of the raw material supply nozzle 11. With this configuration, it is possible to change the distance between the tip of the classification edge 15 and the tip of the raw material supply nozzle 11 to adjust the widths of the fine powder discharge passage 36 and the coarse powder discharge passage 37. Become.

  For example, as the classification edge 15 is moved to the right in FIG. 2, the distance between the tip of the classification edge 15 and the tip of the raw material supply nozzle 11 becomes smaller, so the width of the fine powder discharge passage 36 becomes smaller. The width of the coarse powder discharge passage 37 is increased by the amount that the width of the fine powder discharge passage 36 is reduced. On the other hand, as the classifying edge 15 is moved to the left in FIG. 2, the distance between the tip of the classifying edge 15 and the tip of the raw material supply nozzle 11 increases, and the width of the fine powder discharge channel 36 increases. The width of the coarse powder discharge passage 37 is reduced by the amount that the width of the fine powder discharge passage 36 is increased.

  The distance between the tip of the classification edge 15 and the tip of the raw material supply nozzle 11 can be set as appropriate. For example, as shown in FIG. 4, the tip of the classification edge 40 in the conventional airflow classifier The distance from the Coanda block 41 is “a”, the distance between the tip of the classification edge 40 and the tip of the raw material supply nozzle 11 is “b”, and the fine powder discharge flow in the airflow classifier 10 of the present invention. The width of the path 36 is “A”, the distance between the tip of the classification edge 15 and the tip of the raw material supply nozzle 11 is “B”, and a / b = about 0.5, whereas A / B = about It is desirable to set it to be 0.7 to 1.0.

  In the airflow classifier 10 according to the present embodiment, an inlet passage 30 through which a gas such as external air flows into the classification region 34, a classification region 34 in which the powder raw material is classified, and the powder raw material after classification A discharge channel 35 through which gas is discharged is formed.

(Inlet channel)
The inlet flow passage 30 is formed between the first inclined surface 12 a of the coarse powder side block 12 and the raw material supply side block 13. In the inlet air flow path 30, a part of the gas flows into the classification region 34 along the gas injection direction from the rear of the upper part of the raw material supply nozzle 11 to the classification region 34 with respect to the gas injection direction of the raw material supply nozzle 11. The gas inflow angle is configured to be larger on the side farther from the injection port of the raw material supply nozzle 11. In the present embodiment, at least the side of the raw material supply side block 13 is included in the inlet flow path 30. The first incoming airflow 31 flowing through the second airflow 32 and the second incoming airflow 32 flowing through the coarse powder side block 12 are formed.

  The first incoming air flow 31 is formed along the first inclined surface 13 a, the curved surface 13 b, and the second inclined surface 13 c of the raw material supply side block 13. That is, a part of the flowing gas flows along the first inclined surface 13a and the curved surface 13b of the raw material supply side block 13, and further, in the gas injection direction S of the raw material supply nozzle 11, that is, the second inclined surface 13c. Along the raw material supply nozzle 11, the gas flows toward the classification region 34.

  The second incoming air flow 32 is formed by the first inclined surface 12 a of the coarse powder side block 12. A part of the gas flowing into the apparatus crosses the gas injection direction S of the raw material supply nozzle 11 along the side opposite to the raw material supply nozzle 11, that is, along the first inclined surface 12 a of the coarse powder side block 12. Flows toward the classification area 34.

  The first to third rectifying plates 21, 22, and 23 are juxtaposed along the width direction of the intake air flow path 30 in the present embodiment, and a part of the gas that flows in the first intake air flow 31. And it is comprised so that it can pass through these 1st-3rd rectification | straightening plates 21, 22, and 23 as airflows other than the 2nd incoming airflow 32. FIG.

  The directions of the first to third rectifying plates 21, 22, and 23 are set to different directions. That is, the first rectifying plate 21 disposed on the coarse powder side block 12 side is provided in a direction along the coarse powder side block 12. The third rectifying plate 23 arranged on the raw material supply side block 13 side is provided in a direction along the second inclined surface of the raw material supply side block 13. The second rectifying plate 22 disposed between the first rectifying plate 21 and the third rectifying plate 23 is provided in a direction along an approximately intermediate direction between the direction of the first rectifying plate 21 and the direction of the third rectifying plate 23. ing.

  By the first to third rectifying plates 21, 22, and 23, the gas inflow angle in the inlet passage 30 with respect to the classification region 34 with respect to the gas injection direction S of the raw material supply nozzle 11 becomes farther from the injection port of the raw material supply nozzle 11. Gradually grows. That is, the gas flow in the intake air flow path 30 continuously changes from the first incoming air flow 31 to the second incoming air flow 32, and the flow path closer to the first incoming air flow 31 side follows the direction of the first incoming air flow 31. The flow path closer to the second incoming air flow 32 is along the direction of the second incoming air flow 32.

  As shown in FIG. 3, the first to third rectifying plates 21, 22, and 23 in the present embodiment are all provided on the same disk member 24, and the whole constitutes a rectifying member 20 as one member. The rectifying member 20 is attached so as to be rotatable about the axis of the disk member 24 by fitting the disk member 24 into a circular recess 33 formed in the inlet air flow path. By rotating the rectifying member 20, the directions of the first to third rectifying plates 21, 22, and 23 are simultaneously changed. Therefore, the user simply rotates the disk member 24 of the rectifying member 20 to rotate the first to third rectifying plates 20. The inclination angles of the third rectifying plates 21, 22, and 23 can be adjusted and set simultaneously.

  In addition, in this embodiment, although the structure which provides the 1st-3rd rectifier plates 21,22,23 is shown, it is not limited to this structure, As a structure which provides still more rectifier plates Also good. That is, the rectifying plate that is disposed closer to the coarse powder side block 12 and the rectifying plate that is disposed in a direction closer to the coarse powder side block 12 and closer to the second inclined surface of the raw material supply side block 13 , Provided in a direction along the second inclined surface of the raw material supply side block 13, from the rectifying plate on the coarse powder side block 12 side to the rectifying plate on the raw material supply side block 13 side (rectification on the raw material supply side block 13 side) What is necessary is just to comprise so that the direction may change gradually from a board to the baffle plate of the coarse powder side block 12 side.

(Discharge flow path)
The discharge channel 35 discharges the raw material classified in the classification region 34 together with the gas. The discharge flow path 35 has at least a fine powder discharge flow path 36 and a coarse powder discharge flow path 37, and the fine powder discharge flow path 36 and the coarse powder discharge flow path 37 are partitioned by the classification edge 15. 36 is arranged in the vicinity of the raw material supply nozzle 11.

  The fine powder discharge flow path 36 is formed by the curved surface 15 b of the classification edge 15, the upper surface 16 b of the classification edge block 16, and the lower surface 14 a of the lower side block 14. The fine powder discharge flow path 36 is bent downward from the front end of the raw material supply nozzle 11 so that the gas flows from the front end side to the base side below the raw material supply nozzle 11, and is oriented along the gas injection direction S of the raw material supply nozzle 11. The gas flowing into the fine powder discharge flow path 36 is configured to flow in a direction R opposite to the gas injection direction S of the raw material supply nozzle 11.

  The coarse powder discharge channel 37 is formed in a direction along the vertical direction by the inclined surface 15a of the classification edge 15, the second inclined surface 12b of the coarse powder side block 12, the vertical surface 12c, and the side surface 16a of the classification edge block 16. The gas that has flowed into the coarse powder discharge channel 37 flows in the downward direction D.

  In the present embodiment, the configuration in which the discharge channel 35 has only two discharge channels, the fine powder discharge channel 36 and the coarse powder discharge channel 37, is not limited to this configuration. It is good also as a structure which provides many discharge flow paths. For example, a separate classification edge is provided between the fine powder discharge flow path 36 and the coarse powder discharge flow path 37, and the medium powder discharge flow path for classifying medium powder having a particle size larger than the fine powder and smaller than the coarse powder. It is good also as a structure which provides.

[4] Classifying operation When the blower 9 (see FIG. 1) is operated, a gas such as external air is sucked into the airflow classifier 10, passes through the inlet air flow path 30, and further passes through the classification region 34 to discharge fine powder. A classified airflow that flows toward the flow path 36 and the coarse powder discharge flow path 37 is formed.

  The powder raw material is injected from the raw material supply nozzle 11 to the classification region 34 in the apparatus. At this time, an inertial force acts on each particle of the powder raw material, so that a particle having a larger particle size and a heavier particle rides a classification airflow at a position farther away from the material supply nozzle 11, and a particle having a smaller particle size and a lighter material is supplied. Get on the classified airflow at a position closer to the nozzle 11.

In this embodiment, the classification edge 15 becomes a classification point, and the powder raw material is classified into fine powder and coarse powder. In the present invention, with respect to the powder raw material injected from the raw material supply nozzle 11, the gas flowing from above the raw material supply nozzle 11 into the classification region 34 along the gas injection direction S from behind (the first incoming air flow 31). And a part of the fine powder discharge flow path 36 is constituted by the lower surface 14a of the lower block 14 extending downward at an acute angle starting from the tip of the raw material supply nozzle 11, and the fine powder discharge flow from the classification region 34 By configuring the gas flowing out to the passage 36 to flow downward in the vicinity of the tip of the raw material supply nozzle 11, even if the Coanda effect by the conventional Coanda block is not used, compared to the conventional airflow classifier, It was made based on the knowledge discovered by the present inventors that classification performance when removing coarse powder from powder raw material (classified raw material) can be enhanced.

  In the present embodiment, the classification region 34 is arranged so that the powder material injected from the material supply nozzle 11 further crosses the gas injection direction S of the material supply nozzle 11 on the side opposite to the material supply nozzle 11. The classifying performance is further improved by applying the gas (second incoming air flow 32) flowing toward the air.

  The classified fine powder passes through the fine powder discharge flow path 36, passes through the fine powder suction pipe 38, and is collected in the cyclone 6 for collecting fine powder, and is used industrially. On the other hand, the classified coarse powder passes through the coarse powder discharge passage 37 and further passes through the coarse powder suction pipe 39 and is collected in the coarse powder collecting cyclone 7. About the collect | recovered coarse powder, after grind | pulverizing with a well-known fine grinder as needed, you may make it classify again by the airflow type | formula classifier of this invention.

[5] Surface treatment for adhesion prevention In order to prevent turbulence and blockage of the classification air flow in the airflow classifier due to adhesion / fixation of the powder raw material, the inner surface of the casing of the airflow classification apparatus and the contact portion with the powder raw material Further, it is preferable to perform buffing, electrolytic polishing, coating such as PTFE, and metal plating such as Ni or Cr.

  For the coating, a fluorine-based organic coating bicoat (manufactured by Yoshida SKT Co., Ltd.), tribofinish (manufactured by Brasstron Co., Ltd.), urethane, etc. having non-adhesiveness and toughness can be used. In the above plating, in addition to metal plating, Kaniflon (Nihon Kanisen Co., Ltd.) made of Ni and PTFE, Nidax (Ulvac Techno Co., Ltd.) and the like can be used.

[6] Surface treatment for wear resistance For members that come into contact with powder raw materials in the equipment, such as classification edges and raw material supply nozzles, electropolishing, coating and plating of hard metals and ceramics, ultra-ceramics and cermets, etc. It is preferable to perform hard alloy sintering, thermal spraying / welding, overlay welding, carburizing treatment, nitriding treatment, ion plating, and blasting treatment.

  For the above coating, diamond-like carbon with a hard carbon film, chromium oxide sprayed locale (manufactured by Nippon Coating Industry Co., Ltd.), Chromax (manufactured by Chunichi Craft Co., Ltd.), and plating with hard chromium or chromium carbide. Daicron (Chiyoda Daiichi Kogyo Co., Ltd.) can be used.

  In addition, colmoloy (made by Wall Colmoloy) for vacuum welding, adaman clad (made by Osaka Welding Kogyo Co., Ltd.) for sintering cermet, tribofinish (made by Brasstron Co., Ltd.) and glass for blasting For beads (manufactured by Nagato Metallicon Mfg. Co., Ltd.) and overlay welding, stellite (manufactured by Deloro Stellite Group) or ING alloy (manufactured by Nimine Co., Ltd.) can be used.

[7] Operating environment during classification As for the environment in the apparatus during operation of the airflow classifier of the present invention, (1) the temperature is preferably lower (low temperature) to prevent fusion, and (2) humidity In order to prevent adhesion and sticking, the lower one (dehumidification) is preferable. (3) The gas is preferable as the specific gravity difference from air is larger because the locus changes depending on the air density. (4) The oxygen concentration is explosion-proof ( The lower one is preferable for avoiding dust explosion).

[8] Toner Production Method The airflow classifier of the present invention can be suitably used in a production process for producing fine powdery toner used for coloring paper with, for example, a copying machine or a laser printer. it can.

  A toner is a product in which a binder resin, a colorant, and a charge control agent, which are raw materials, are mixed, melted and kneaded by an extruder, cooled and solidified, and pulverized and classified into a desired particle size range. To do. The above is the basic toner manufacturing process, but in the process of pulverization, classification, and external addition, further processing steps such as spheroidization and surface modification may be included. That is, the fine powder after pulverization or the fine powder after classification is made into a product as it is or after being spheroidized and / or surface-modified and further added with particulate silica and a charge control agent. In addition, a classification step (coarse powder classification or fine powder classification) may be performed before and after spheroidization, surface modification, and external addition treatment between coarse pulverization and fine pulverization.

  Next, the pulverization process and the classification process will be described. The coarsely pulverized toner raw material is finely pulverized, and then the coarse powder and fine powder are removed in a classification step to obtain particles in a desired range. Particles that do not contain coarse powder can be obtained with a fine pulverizer with a built-in classification mechanism. However, fine pulverizers with no built-in classification mechanism contain coarse powder, so it is necessary to classify the coarse powder after pulverization. . In this case, the coarse powder obtained in the coarse powder classification step can be returned to the fine pulverizer and pulverized again. Further, in the fine powder classification step, fine powder having a predetermined particle diameter or less is removed using a fine powder classifier having a smaller classification point. The fine powder classification step may be performed prior to the coarse powder classification step.

  Further, the following surface treatment process may be further performed on the toner particles obtained by pulverization or classification. That is, toner particles are spheroidized, other fine particles are embedded in the surface of the particles to modify the surface, or fine particle silica or a charge control agent is attached as an external additive. Usually, the external additive is carried out at a stage before final product production, but in some cases, the external additive may be added before or after classification or spheroidization. For example, a classification process (coarse powder classification or fine powder classification) can be performed after spheronization or surface treatment. After the general pulverization / classification process in the toner manufacturing process, the order of each process and the addition or omission of the process can be appropriately changed according to the purpose of the product, the processing conditions, and the like.

  As described above, the most basic flow for producing a toner can be expressed as (raw material) → (mixing) → (cooling solidification) → (pulverization / classification) → (product), but (pulverization / classification) There are the following devices that can be used for the respective processing steps of coarse pulverization, fine pulverization, ultrafine pulverization, classification, surface treatment, and external addition as more specific processes.

  The equipment used for coarse pulverization includes hammer mills, pin mills, etc. Specific examples of product names include Fezamil (manufactured by Hosokawa Micron Corporation), Coroplex (manufactured by Hosokawa Micron Corporation), and Pulverizer (Hosokawa Micron Corporation). Product), ACM pulverizer (manufactured by Hosokawa Micron Corporation), kryptron (manufactured by Earth Technica Corporation), and the like.

  There are jet mills (airflow pulverizers), mechanical pulverizers, etc. as the equipment used for fine pulverization. Examples of specific product names include ACM Pulverizer (manufactured by Hosokawa Micron Corporation), Inomizer (Hosokawa Micron Corporation). Product), Gracis (manufactured by Hosokawa Micron Co., Ltd.), turbo mill (manufactured by Freund Turbo Co., Ltd.), kryptron (manufactured by Earth Technica Co., Ltd.), and a pulverizer according to the present invention.

  Equipment used for ultra-fine grinding includes jet mills (airflow type grinders), mechanical grinders, etc. Specific examples of product names include Gracis (manufactured by Hosokawa Micron Corporation), turbo mill (Freund turbo) Co., Ltd.), counter jet mill AFG (manufactured by Hosokawa Micron Corporation), and the like.

  Examples of devices used for classification include the airflow classifier of the present invention and a rotary blade classifier. Specific examples of product names include turboplex (manufactured by Hosokawa Micron Corporation), TSP separator (Hosokawa Micron ( TTSP separator (manufactured by Hosokawa Micron Corporation), Elbow Jet (manufactured by Nippon Coke Industries Co., Ltd.), DSF (manufactured by Nippon Pneumatic Industry Co., Ltd.), and the like.

  Examples of surface treatment equipment include spheronization equipment, surface modification equipment, etc. Specific examples of product names include Mechanofujutsu (manufactured by Hosokawa Micron), Nobilta (manufactured by Hosokawa Micron), and cyclomix. (Manufactured by Hosokawa Micron Corporation), Faculty (manufactured by Hosokawa Micron Corporation), FM mixer (manufactured by Nippon Coke Industries Co., Ltd.), thermal spheronizer and the like.

  There is an external additive mixer as a device used for external addition processing, and specific examples of product names include Mechanofujuon (manufactured by Hosokawa Micron Corporation), Nobilta (manufactured by Hosokawa Micron Corporation), and Cyclomix (Hosokawa Micron Corporation). )), Faculty (manufactured by Hosokawa Micron Corporation), FM mixer (manufactured by Nippon Coke Industries Co., Ltd.), COMPOSI (manufactured by Nippon Coke Industries Co., Ltd.), and the like.

[9] Other uses of the airflow classifier of the present invention Note that the airflow classifier of the present invention is not only classified after fine pulverization or ultrafine pulverization, but also product powder after spheronization and surface modification. It can also be applied as an apparatus for removing foreign matters such as fine powder or coarse particles therein.

[Second Embodiment]
Hereinafter, a second embodiment of the airflow classifier of the present invention will be described with reference to the drawings. In order to avoid redundant description, the same reference numerals are given to configurations that exhibit the same operations as those described in the first embodiment, and description thereof will be omitted, and only different configurations will be mainly described.

  The airflow classifier of the present embodiment further includes a coarse particle discharge channel 38 in addition to the fine powder discharge channel 36 and the coarse powder discharge channel 37 as the discharge channel 35.

  The coarse particle discharge channel 38 is formed in the coarse powder side block 12. The coarse particle discharge channel 38 has an inflow port 39 disposed opposite to the injection port of the raw material supply nozzle 11, and is bent into a “<” shape from the inflow port 39 to join the coarse powder discharge channel 37. . Note that the width of the coarse particle discharge channel 38 in the present embodiment is set to be smaller than the width of each of the fine powder discharge channel 36 and the coarse powder discharge channel 37.

  When coarse particles having a particle diameter of several tens of μm to several thousand μm are included in the powder raw material, the coarse particles injected from the raw material supply nozzle 11 have a large inertial force, so that the action of the gas flowing in from the inlet passage 30 is large. Even if it is received, the traveling direction may be slightly changed, and it may not flow smoothly along the coarse powder discharge passage 37.

  That is, in the airflow classifier of the first embodiment described above, the coarse particles ejected from the raw material supply nozzle 11 go straight along substantially the gas injection direction and face the injection port of the raw material supply nozzle 11. As a result, the coarse particles may be mixed into the fine powder discharge flow path 36.

  However, according to the present embodiment, the coarse particles that are jetted from the raw material supply nozzle 11 and fly straight forward flow into the coarse particle discharge channel 38 from the inlet 39. Therefore, the injected coarse particles do not collide with the coarse powder side block 12 and rebound, and there is no possibility that the coarse particles are mixed into the fine powder discharge flow path 36. The coarse particles join the coarse powder discharge passage 37 through the coarse particle discharge passage 38 and are discharged out of the apparatus together with the coarse powder.

(Example)
In general, when a raw material is pulverized by a mechanical pulverizer to obtain a toner powder having an average particle diameter of 6.5 μm, there are several percent of particles having a particle diameter of 10 μm or more called “coarse powder”. In order to make this a “fine powder” of the final product, it is necessary to classify and remove the “coarse powder”.

  As an example, a test result when a classification operation is performed on toner powder having an average particle size of 6.5 μm using the airflow classifier (first embodiment) of the present invention will be described below.

  About the airflow classifier (1st Embodiment) of this invention, according to the driving | running conditions shown in the following Table 1, 4 classification operation was implemented.

  The distance (B) in Table 1 is the distance from the tip of the raw material supply nozzle 11 (lower end of the injection port) to the tip of the classification edge 15, and the classification edge 15 extends along the upper surface 16 b of the classification edge block 16. Thus, it was set by moving from the fine powder discharge channel 36 side to the coarse powder discharge channel 37 side (see FIGS. 2 and 4). The distance (B) set in each classification operation is the first time: 60 mm, the second time: 61 mm, the third time: 62 mm, and the fourth time: 63 mm.

(Comparative example)
As a comparative example, a test result when a classification operation is performed on a toner powder having the same average particle diameter of 6.5 μm as in the above-described example using a conventional airflow classifier using the Coanda effect will be described below.

  The conventional airflow classifier was subjected to four classification operations according to the operating conditions shown in Table 2 below.

  The distance (b) in Table 2 is the distance from the tip of the material supply nozzle 11 (lower end of the injection port) to the tip of the classification edge 40 (see FIG. 4). The distance (b) set in each classification operation is the first time: 61 mm, the second time: 63 mm, the third time: 64 mm, and the fourth time: 66 mm.

(Comparison of test results in Examples and Comparative Examples)
As shown in Table 1 above, the coarse powder recovery rate in the airflow classifier of the present invention is as follows: 1st time: 12.8%, 2nd time: 8.6%, 3rd time: 6.7%, 4th time: 5 The ratio of coarse powder (ratio of coarse powder contained in fine powder by volume ratio) is 1st: 0.4%, 2nd: 0.6%, 3rd: 1.1%, 4 Round: 1.5%.

  On the other hand, as shown in Table 2 above, the coarse powder recovery rate in the conventional airflow classifier is as follows: 1st time: 19.0%, 2nd time: 17.0%, 3rd time: 8.0%, 4th time: The ratio of coarse powder (ratio of coarse powder contained in fine powder by volume ratio) is 1st: 0.2%, 2nd: 0.5%, 3rd: 1.5%, Fourth time: 2.1%.

  FIG. 6 summarizes the results of the coarse powder recovery rate and the coarse powder ratio (ratio of coarse powder contained in fine powder by volume ratio) in Tables 1 and 2 above.

  The amount of fine powder erroneously collected as coarse powder among the pulverized toner powder is small (that is, the coarse powder collection rate is small), and the volume ratio of the coarse powder contained in the fine powder is small (that is, the coarse powder ratio). The smaller the airflow classifier, the higher the classification performance.

  As shown in FIG. 6, the measured value of the airflow classifier of the present invention is generally located on the lower left side of the graph as compared with the measured value of the conventional airflow classifier. That is, it can be said that the airflow classifier of the present invention has a smaller coarse powder recovery rate and a smaller coarse powder ratio than the conventional airflow classifier. Therefore, it can be seen that the airflow classifier of the present invention has better classification performance than the conventional airflow classifier.

  Next, the classification operation was performed according to the operating conditions shown in Table 3 below for each of the airflow classifiers of the first embodiment and the second embodiment described above.

In this example, a powder having a particle size of 45 μm or more obtained by sieving was used as coarse particles.
As shown in Table 3, in the airflow classifier of the second embodiment, the proportion of coarse particles contained in the classified fine powder (processed fine powder) is significantly reduced as compared with the airflow classifier of the first embodiment. It was.

  The airflow classifier according to the present invention can be suitably used in industrial fields where it is necessary to classify and use powder raw materials in which particles of various particle sizes are mixed, such as toner raw materials and chemical raw materials.

DESCRIPTION OF SYMBOLS 10 Airflow classifier 11 Raw material supply nozzle 12 Coarse powder side block 13 Raw material supply side block 14 Lower side block 14a Lower surface (gas contact surface)
15 Classification edge 16 Classification edge block 20 Rectifying member 21 to 23 First to third rectifying plate 24 Disk member 30 Inlet flow path 31 First inflow air flow 32 Second inflow air flow 34 Classification area 35 Discharge flow path 36 Fine powder discharge flow path 37 Coarse powder discharge channel 38 Coarse particle discharge channel 39 Inlet

Claims (9)

A classification area in which the material to be classified is classified;
An inlet flow path for flowing gas into the classification region;
A raw material supply nozzle for injecting the raw material to be classified from the side into the classification region;
A lower block disposed adjacent to the lower side of the raw material supply nozzle;
A discharge passage for discharging the classified raw material classified from the classification region together with the gas,
A part of the gas flowing through the inlet channel is configured to flow into the classification region along the gas injection direction from behind the upper part of the raw material supply nozzle,
The discharge flow path has at least a fine powder discharge flow path and a coarse powder discharge flow path, and is configured so that the fine powder discharge flow path is in the vicinity of the raw material supply nozzle,
The gas contact surface of the lower block extending downward at an acute angle starting from the tip of the raw material supply nozzle constitutes a part of the fine powder discharge channel,
An airflow classifier configured so that gas flowing out from the classification region to the fine powder discharge passage flows downward in the vicinity of the tip of the raw material supply nozzle.   2. The air flow type according to claim 1, wherein the fine powder discharge channel is configured such that gas flows in a direction opposite to a gas injection direction of the raw material supply nozzle along a gas contact surface of the lower block. Classification device.   A plurality of rectifying plates are provided in the inlet passages in different directions, and the rectifying plates allow a gas inflow angle to the classification region with respect to the gas injection direction of the raw material supply nozzle to be from the injection port of the raw material supply nozzle. The airflow classifier according to claim 1 or 2, wherein the airflow classifier is configured to become larger as the distance increases.   4. The plurality of current plates are integrally provided on a disk member, the disk members are rotatably mounted around an axis, and the inclination angles of the plurality of current plates are adjusted and set simultaneously. The airflow classifier described in 1. The fine powder discharge channel and the coarse powder discharge channel are partitioned by a classification edge,
The arrangement position of the said classification edge is comprised so that a change between the front-end | tip of the said classification edge and the front-end | tip of the said raw material supply nozzle is possible, The change of any one of Claims 1-4. Airflow classifier.   The airflow classifier according to claim 5, wherein the classification edge is attached so as to be movable in a horizontal direction with respect to a gas injection direction of the raw material supply nozzle.   The airflow type classification device according to claim 6, wherein a tip of the classification edge is formed by an inclined surface constituting a part of the coarse powder discharge flow path and a curved surface constituting a part of the fine powder discharge flow path. . The gas flow classifier according to any one of claims 1 to 7, wherein the gas contact surface of the lower block includes a curved surface or a flat surface extending downward from the tip of the raw material supply nozzle.   9. The apparatus according to claim 1, wherein the discharge flow path further includes a coarse particle discharge flow path, and the coarse particle discharge flow path includes an inflow port disposed to face an injection port of the raw material supply nozzle. The airflow classifier described.

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