Toner classifier and toner manufacturing method

Abstract

To provide a classification device for toners which suppresses pressure losses due to a classification rotor and indicates a good yield even when manufacturing a toner of small particle size, and a method for manufacturing the toner.SOLUTION: Provided is a classification device for toners that includes a classification rotor and has a blade A extending from the center of rotation of the classification rotor to the outer circumferential side and a blade B having the length longer than the blade A, the number of blades A arranged between two adjacent blades B being 1 to 3 independently of each other, the blades B having a first bent part, the blades A and blades B are installed so as to be located progressively upstream in the rotation direction of the classification rotor as it goes toward the outer circumferential edge from the rotation center edge of the classification rotor, with the rotation center of the classification rotor and the blades A and blades B arranged so as to satisfy a prescribed relationship. Also provided is a method for manufacturing a toner, which includes a classification step in which classification processing is performed on the particles to be classified, using said classification device for toners.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to a toner classifying device and a toner manufacturing method used in electrophotography, electrostatic recording, electrostatic printing, and toner jet systems. [Background technology]

[0002] In recent years, electrophotographic full-color copiers have become widely used and are beginning to be applied to the printing market. The printing market is now demanding high speed, high image quality, and high productivity while supporting a wide range of media (paper types). In the case of toner, small particle size and a sharp particle size distribution stabilize the charging properties, which in turn stabilizes the developing and transferring properties, thereby enabling high image quality.

[0003] A melt-kneading pulverization method is known as one of the common methods for producing toner. A specific example of a method for producing toner particles using the melt-kneading pulverization method is as follows: Toner raw materials such as a binder resin, a colorant, and a release agent are melted and kneaded, cooled and solidified, and then the kneaded mixture is pulverized by a pulverizing means to obtain toner particles. Thereafter, as necessary, the toner is produced by classifying the particles to have a desired particle size distribution, adjusting the circularity by making the toner particles spherical through heat treatment, or adding a fluidizing agent such as inorganic fine particles.

[0004] Various types of crushing devices are used as a means for crushing kneaded materials, and one known example is a mechanical crushing device (Patent Document 1) that has a rotor supported by a central rotating shaft and having multiple convex and concave portions on its outer surface inside a casing that has an inlet and outlet for the material to be crushed, and a stator that is positioned outside the rotor with a predetermined gap from the outer surface of the rotor and has multiple convex and concave portions on its inner surface, and crushes the material to be crushed by colliding with the convex or concave portions of the rotor or stator as the material to be crushed passes through a processing section where the rotor and stator face each other, carried by the air flow that flows from the inlet to the outlet.

[0005] Furthermore, fine powders generated during the grinding process are mixed into the pulverized material that has been ground to the desired particle size by a grinding device. If these fine powders are present in the toner, they can cause problems in the electrophotographic process, such as fogging, and are therefore generally removed by classification.

[0006] Known methods for producing toner that involve classification using a classifier include a method for producing toner that uses an airflow classifier that utilizes the Coanda effect (Patent Document 2) and a method for producing toner that uses a centrifugal air classifier (Patent Document 3).

[0007] When using a centrifugal air classifier, the pulverized mixture of toner raw materials (the particles to be classified) is transported from the inlet to the vicinity of the outer periphery of the classifying rotor by an airflow that flows inward from the outer periphery of the classifying rotor, where centrifugal force is applied to the particles at the outer periphery of the classifying rotor as the classifying rotor rotates. Because the centrifugal force acting on the particles to be classified is a force that flows outward from the classifying rotor and is proportional to the mass of the particles, the centrifugal force acting on the fine powder in the particles to be classified is smaller than the drag exerted by the airflow that flows inward from the outer periphery of the classifying rotor. Therefore, the fine powder passes between the blades of the classifying rotor and is collected by a fine powder collection means that is connected to the inside of the classifying rotor, and the classified particles from which the fine powder has been removed are collected by a classified material collection means located outside the classifying rotor, thereby being classified.

[0008] Also proposed is a method for producing toner using a classification means having a plurality of blades arranged at regular intervals on the same circumference, with each blade being arranged at an angle θ with respect to a line connecting the center of the classification rotor and the tip of the blade (Patent Document 4). In the classification means used in this production method, particles that get into the gaps between the blades from the outside of the classification rotor that rotates at high speed are The air is separated into a component that flows toward the center of rotation and a component that is expelled to the outside of the classifying rotor, creating a vortex. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-237816 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-201890 [Patent Document 3] Japanese Patent Application Laid-Open No. 2008-26457 [Patent Document 4] Japanese Patent Application Laid-Open No. 2010-160374 Summary of the Invention [Problem to be solved by the invention]

[0010] As mentioned above, classification is achieved by adjusting the balance between the drag and centrifugal forces acting on the particles to be classified. However, due to factors such as turbulence in the airflow within the classifier, aggregation of the particles to be classified, variations in the speed at which the particles to be classified approach the classifying rotor, and vortices occurring between the blades of the classifying rotor, particles that should not be taken in as fine powder may be mistakenly sucked in and removed. It has been confirmed that the closer the average particle size of the particles to be classified is to the particle size of the fine powder to be removed in the classification process, the greater the proportion of particles removed by mistaken suction. Therefore, it has been confirmed that reducing the particle size of toner reduces the yield of the classification process.

[0011] Furthermore, it is believed that the vortices generated in the toner manufacturing method described in Patent Document 4 are generated in a shape that follows the blades. It has been confirmed that when the angle θ exists, the vortices are generated outside the rotor rather than the classification rotors that are arranged in the aforementioned radial straight line, reducing the rate of erroneous absorption of the particles to be classified and improving yield. However, it has been confirmed that if the angle θ is too large, the gap between the inner blades of the classification rotor becomes too narrow, making it difficult for fine powder to pass through, resulting in issues such as insufficient fine powder removal and increased pressure loss.

[0012] As mentioned above, reducing the particle size of toner is required to achieve high image quality. The particle size of the pulverized material obtained in the pulverization process after melting and kneading a mixture of toner raw materials determines the particle size of the final toner. Therefore, reducing the particle size of the pulverized material is necessary to reduce the particle size of toner. The classification process is a process for removing fine particles that can cause problems in the electrophotographic process. However, reducing the particle size of toner results in the average particle size of the pulverized material becoming closer to the particle size of the fine particles that should be removed in the classification process. As a result, some particles that should not be removed because they have an appropriate particle size for toner are also removed as fine particles, resulting in a decrease in yield.

[0013] Furthermore, when classifying using a centrifugal air classifier, possible measures to suppress the incorporation of classified particles that should not be removed include increasing the number of blades in the classifying rotor or increasing the angle θ that each blade makes with respect to the line connecting the center of the classifying rotor and its tip. However, these measures increase the pressure loss caused by the classifying rotor, which increases the load on the blower.

[0014] The present disclosure provides a toner classification device and a toner manufacturing method that solves the above problems, suppresses pressure loss due to the classification rotor, and shows good yield even when producing toner with small particle size. [Means for solving the problem]

[0015] The present disclosure provides: A toner classifying device equipped with a classification rotor, The classification rotor has a plurality of blades extending from the rotation center side to the outer periphery side of the classification rotor, The plurality of blades are arranged at predetermined intervals from one another, the gap forms an opening facing the rotation center region of the classification rotor; the plurality of blades includes a first blade group consisting of blade A and a second blade group consisting of blade B having a length longer than that of blade A; The blades A have approximately the same length and are arranged at intervals so that they trace approximately the same trajectory when the classifying rotor rotates. The blades B have approximately the same length and are arranged at intervals so that they trace approximately the same trajectory when the classifying rotor rotates. The number of blades A arranged between two adjacent blades B is independently 1 to 3, The blade B has a first bent portion, The blades A and B are provided so as to be positioned upstream in the rotation direction of the classification rotor from the end of the classification rotor on the rotation center side toward the end of the classification rotor on the outer periphery side, the distance between the rotation center of the classification rotor and the outer peripheral end of the blade A is approximately equal to the distance between the rotation center of the classification rotor and the outer peripheral end of the blade B, a distance between the rotation center of the classification rotor and the end of the blade A on the rotation center side is approximately equal to a distance between the rotation center of the classification rotor and the first bent portion of the blade B; the distance between the rotation center of the classification rotor and the end of the blade A on the rotation center side is greater than the distance between the rotation center of the classification rotor and the end of the blade B on the rotation center side; In a cross section of the classification rotor cut in a direction perpendicular to the rotation axis of the classification rotor, (i) the angle θ1 (°) formed by the line connecting the rotation center of the classification rotor and the end of the blade A on the rotation center side and the portion of the blade A closer to the outer periphery than the end of the rotation center side is 40° to 65°, (ii) the angle θ3 (°) formed by the line connecting the rotation center of the classification rotor and the first bent portion of the blade B and the portion of the blade B closer to the outer periphery than the first bent portion is approximately the same as the angle θ1; (iii) the angle θ2 (°) formed by the line connecting the rotation center of the classification rotor and the first bend portion of the blade B and the line connecting the end of the rotation center side of the blade B and the first bend portion of the blade B is 0°≦θ2≦θ3×1 / 2 Fulfilling (iv) When the radius of the classification rotor is R and the distance between the rotation center of the classification rotor and the end of the blade B on the rotation center side is L1, R and L1 are 0.35≦L1 / R≦0.65 Fulfilling (v) When the distance between the rotation center of the classification rotor and the first bend portion of the blade B is L2, R, L1, and L2 are 0.35≦(L2-L1) / (R-L1)≦0.70 The present invention relates to a toner classification device that satisfies the above requirements.

[0016] The present disclosure also provides a toner manufacturing method including a classification step of classifying particles to be classified using a toner classification device, The present invention relates to a method for producing toner, wherein the toner classification device is the toner classification device of the present disclosure. [Effects of the Invention]

[0017] According to the present disclosure, it is possible to provide a toner classifying device and a toner manufacturing method that suppress pressure loss due to a classification rotor and that exhibits good yield even when small particle size toner is manufactured. This can be done. [Brief explanation of the drawings]

[0018] [Figure 1] Schematic diagram of the classification rotor used in the examples [Figure 2] Illustration of the swirling flow inside the rotor [Figure 3] Schematic diagram of a toner classification device used in the examples [Figure 4] Schematic diagram of the dispersion rotor used in the examples [Figure 5] Schematic diagram of a guide means used in the embodiment [Figure 6] Schematic diagram of the liner used in the examples [Figure 7] Schematic diagram of the classification rotor used in the examples [Figure 8] Schematic diagram of the classification rotor used in the examples [Figure 9]Schematic diagram of the classification rotor used in the examples [Figure 10] Schematic diagram of the classification rotor used in the examples [Figure 11] Schematic diagram of the classification rotor used in the examples [Figure 12] Schematic diagram of the classification rotor used in the examples [Figure 13] Schematic diagram of the classification rotor used in the comparative example [Figure 14] Schematic diagram of the classification rotor used in the comparative example [Figure 15] Schematic diagram of the classification rotor used in the comparative example DETAILED DESCRIPTION OF THE INVENTION

[0019] In this disclosure, the expressions "XX or more and YY or less" and "XX to YY" that represent a numerical range mean a numerical range including the lower and upper limits, which are the endpoints, unless otherwise specified. Also, in this disclosure, "fine powder" refers to particles having a particle size significantly smaller than the target particle size.

[0020] FIG. 1 shows a schematic diagram of a classification rotor provided in a toner classifier. The classification rotor has a plurality of blades extending from the rotation center side to the outer periphery side of the classification rotor, The plurality of blades are arranged at predetermined intervals from one another, the gap forms an opening facing the rotation center region of the classification rotor; the plurality of blades includes a first blade group consisting of blade A and a second blade group consisting of blade B having a length longer than that of blade A; The blades A have approximately the same length and are arranged at intervals so that they trace approximately the same trajectory when the classifying rotor rotates. The blades B have approximately the same length and are arranged at intervals so that they trace approximately the same trajectory when the classifying rotor rotates. The number of blades A arranged between two adjacent blades B is independently 1 to 3. Here, "the blades have approximately the same length" does not necessarily mean that the blades have exactly the same length, but also means that the blades have the same length to the extent that the effect of the present disclosure is not impaired.

[0021] The portion of the blade B from the end closest to the rotation center to the first bent portion may be straight or curved, but is preferably straight as shown in Fig. 1. The portion of the blade B from the first bent portion to the end closest to the outer periphery may be straight or curved, but is preferably straight as shown in Fig. 1. When blade B has a second bent portion described below, the portion of blade B from the first bent portion to the second bent portion may be straight or curved, but is preferably straight as shown in Fig. 7. Furthermore, the portion of blade B from the second bent portion to the outer circumferential end portion may be straight or curved, but is preferably straight as shown in Fig. 7. The part of the blade A from the end on the rotation center side to the end on the outer periphery side can be either straight or curved. However, it is preferably linear as shown in FIG. When blade A has a bent portion described below, the portion of blade A from the end portion on the rotation center side to the bent portion may be straight or curved, but is preferably straight as shown in Fig. 7. Furthermore, the portion of blade A from the bent portion to the end portion on the outer periphery side may be straight or curved, but is preferably straight as shown in Fig. 7.

[0022] When the above-mentioned classification rotor is used, the load on the blower is reduced by suppressing the pressure loss caused by the classification rotor, and a toner classification device can be provided that can sufficiently remove fine particles even from small-sized toner and achieve a good yield. The inventors believe that the reasons for this are as follows.

[0023] The centrifugal force acting on an object is expressed as [weight of object] x [radius of rotation] x [square of angular velocity of rotational motion]. Here, the radius of rotation of the particles to be classified is considered to be the distance between the center of rotation of the classifying rotor and the particles to be classified. As mentioned above, it is assumed that vortices are generated between the blades of the classifying rotor, which rotates at high speed, during classification. The presence of these vortices creates a strong localized airflow that draws particles inward, which is thought to draw in and remove particles that should not be removed. If the vortex extends to the inside of the classifying rotor, the particles to be classified will be drawn inward, reducing the distance from the center of rotation and reducing the centrifugal force. This prevents them from returning to the outside of the classifying rotor, resulting in their removal as fine powder.

[0024] In a centrifugal air classifier such as the toner classifier of the present disclosure, the air for transporting powder approaches the outer periphery of the classifying rotor, passes between the blades of the classifying rotor, and then flows to the rotor rotation center and to the fine powder recovery means connected to the rotor rotation center. At this time, friction between the rotor blades and the air, and the generation of vortexes between the blades are thought to be factors that cause pressure loss.

[0025] It is believed that air passing between the blades of a conventional classification rotor becomes a swirling flow as shown in Figure 2(a) and flows toward the fine powder recovery means while coming into contact with the end of the blade of the classification rotor on the rotation center side. The classification rotor of the present disclosure has a first blade group consisting of blade A and a second blade group consisting of blade B that is longer than blade A, as shown in Figure 1. The presence of blade B, which extends closer to the center of rotation of the classification rotor than blade A, restricts the swirling flow, reducing the radius of rotation and the relative speed between the end of the classification rotor blade closest to the center of rotation and the swirling flow, as shown in Figure 2(b). It also reduces contact between the end of blade A closest to the center of rotation and the swirling flow. This is thought to reduce friction between the air and the center of rotation of the classification rotor, thereby reducing pressure loss.

[0026] The number of blades A arranged between two adjacent blades B is independently 1 to 3. When the number of blades A arranged between two adjacent blades B is 4 or more, the blades B do not sufficiently regulate the swirling flow, making it impossible to suppress pressure loss. Also, when there are no blades A, the contact between the end of the blade B on the rotation center side and the swirling flow increases and the distance between the end of the adjacent blade B on the rotation center side becomes narrower, making it difficult for air to pass between the blades, making it impossible to suppress pressure loss. Furthermore, from the viewpoint of easily ensuring dynamic balance as a high-speed rotating body, the number of blades A arranged between blades B is preferably one to three, and more preferably one or two, and even more preferably one of each.

[0027] In the cross section of the classification rotor cut in the direction perpendicular to the rotation axis of the classification rotor, The rotor is arranged so that the straight line connecting the center of rotation of the rotor and the end of blade A on the side of the center of rotation forms an angle θ1 with the part of blade A closer to the outer periphery than the end of blade A on the side of the center of rotation. Here, "a portion of blade A closer to the outer periphery than the end portion on the rotation center side" refers to a portion where blade A overlaps with a straight line connecting the end portion on the rotation center side and the end portion on the outer periphery side of blade A, if blade A does not have a bent portion described later. If blade A has a bent portion described later, it refers to a portion of blade A where blade A overlaps with a straight line connecting the end portion on the rotation center side of blade A and the bent portion of blade A, described later.

[0028] Blade B, which has a length longer than blade A, has a first bend. Furthermore, blade A and blade B are provided so as to be positioned more upstream in the rotation direction of the classification rotor as they move from the end of the classification rotor on the rotation center side to the end on the outer periphery side. Furthermore, the distance between the rotation center of the classification rotor and the outer peripheral end of blade A is approximately equal to the distance between the rotation center of the classification rotor and the outer peripheral end of blade B. Furthermore, the distance between the rotation center of the classification rotor and the end of blade A on the rotation center side is approximately equal to the distance between the rotation center of the classification rotor and the first bent portion of blade B. In addition, the distance between the rotation center of the classification rotor and the end of blade A on the rotation center side is greater than the distance between the rotation center of the classification rotor and the end of blade B on the rotation center side. Furthermore, (ii) the angle θ3 formed by the straight line connecting the center of rotation of the classification rotor and the first bend of the blade B and the part of the blade B closer to the outer periphery than the first bend is arranged to be approximately the same as the angle θ1. Therefore, when the classification rotor rotates, the trajectory drawn by the outer circumferential side of the first bend portion of blade B constituting the second blade set is approximately the same as the trajectory drawn by blade A constituting the first blade set.

[0029] Here, "the distances are approximately equal" does not necessarily mean that the distances are exactly the same, but includes the case where the distances are the same to the extent that the effects of the present disclosure are not impaired. Also, "the classification rotor traces approximately the same trajectory when it rotates" does not necessarily mean that the trajectories are the same to the extent that the effects of the present disclosure are not impaired. Furthermore, when blade B does not have a second bend described below, the term "portion closer to the outer periphery than the first bend portion of blade B" refers to a portion of blade B where blade B overlaps with a straight line connecting the first bend portion of blade B to the outer periphery end of blade B. When blade B has a second bend described below, the term "portion closer to the outer periphery than the first bend portion of blade B" refers to a portion of blade B where blade B overlaps with a straight line connecting the first bend portion of blade B to the second bend portion of blade B.

[0030] (i) θ1 is between 40° and 65°. When θ1 is within the range of 40° and 65°, the position of the vortex generated during classification can be positioned on the outside, and even if particles that should not be removed are drawn into the vortex, the centrifugal force does not become weak and the particles can return to the outside of the classification rotor, which is thought to improve the yield. If θ1 is smaller than 40°, the effect of moving the vortexes generated between the blades of the classification rotor rotating at high speed to the outside is insufficient, and if θ1 is larger than 65°, the distance between the blades of the classification rotor near the ends of the rotation center becomes too close, making it difficult for the fine powder to be removed from the particles to be classified and the air transporting the fine powder to pass through, which causes a decrease in classification performance and an increase in pressure loss. θ1 is preferably 45° to 65°, and more preferably 50° to 65°. Moreover, θ3 is preferably 45° to 65°, and more preferably 50° to 65°.

[0031] (iv) When the radius of the classification rotor is R and the distance between the rotation center of the classification rotor and the end of the blade B on the rotation center side is L1, R and L1 are 0.35≦L1 / R≦0.65 If L1 / R is greater than 0.65, the radius of rotation of the swirling flow that comes into contact with the end of the blade on the rotation center side cannot be made small enough, and if L1 / R is less than 0.35, the The incoming air is concentrated too much on the center of rotation of the classification rotor, negating the effect of suppressing pressure loss. L1 / R is preferably 0.40 or more and 0.55 or less, and more preferably 0.40 or more and 0.50 or less.

[0032] (v) When the distance between the rotation center of the classification rotor and the first bend portion of the blade B is L2, the R, L1 and L2 are 0.35≦(L2-L1) / (R-L1)≦0.70 (L2-L1) / (R-L1) is a value indicating the ratio of the length of blade B from the end of blade B closest to the rotation center to the first bend, and the larger this value, the longer the portion of blade B from the end of blade B closest to the rotation center to the first bend. If (L2-L1) / (R-L1) is less than 0.35, the first bend of blade B will be located closer to the center of rotation of the classification rotor, narrowing the space between adjacent blades. This also shortens the length of the first bend from the center-of-rotation end of blade B, which serves to reduce the radius of rotation of the swirling flow that comes into contact with the center-of-rotation end of the blade. This makes it impossible to reduce pressure loss. If (L2-L1) / (R-L1) is greater than 0.70, the length from the first bend of blade B to the outer edge will be too short, preventing the effect of shifting the position of the vortex generated between blades during classification to the outside, resulting in reduced classification performance. (L2-L1) / (R-L1) is preferably 0.40 or more and 0.65 or less, and more preferably 0.40 or more and 0.60 or less.

[0033] (iii) the angle θ2 (°) formed by the line connecting the rotation center of the classification rotor and the first bend portion of the blade B and the line connecting the end of the rotation center side of the blade B and the first bend portion of the blade B is 0°≦θ2≦θ3×1 / 2 satisfies the following. When the position of the first bend of blade B and L1 are fixed, the length from the end of blade B closest to the rotation center to the first bend is shortest when θ2 = 0°, and the length from the end of blade B closest to the rotation center to the first bend increases as θ2 increases. When θ2 is greater than θ3 × 1 / 2, the contact area between the air and blade B increases, and the distance between the part of blade B closer to the rotation center than the first bend and the end of the blade adjacent to blade B (i.e., blade A) closest to the rotation center is short, which is thought to prevent the pressure loss from being reduced.

[0034] It is preferable that blade A has a bent portion and satisfies at least one selected from the group consisting of the following (vi) to (viii). (vi) When the distance from the rotation center of the classification rotor to the end of the blade A on the rotation center side is L3 and the distance from the rotation center of the classification rotor to the bent portion of the blade A is L4, 0.65≦(L4-L3) / (R-L3)≦0.85 It is preferable to satisfy the following. When (L4-L3) / (R-L3) is 0.65 to 0.85, pressure loss due to the classification rotor is suppressed, and the fine powder removal capacity and yield are improved. (L4-L3) / (R-L3) is more preferably 0.70 to 0.80.

[0035] (vii) The angle θ4 formed by the line connecting the end of the blade A closest to the center of rotation to the bent portion of the blade A and the line connecting the bent portion of the blade A to the end of the blade A closest to the outer periphery is preferably 5° to 25°. When θ4 is 5° to 25°, the pressure loss caused by the classification rotor is suppressed, and the fine powder removal capacity and yield are improved. θ4 is more preferably 10° to 20°.

[0036] (viii) blade B has a second bent portion on the outer circumferential side of the first bent portion, a distance L4 between the rotation center of the classification rotor and the bent portion of the blade A and a distance L5 between the rotation center of the classification rotor and the second bent portion of the blade B are approximately equal; a straight line connecting the bent portion of the blade B and the second bent portion of the blade B; and the line connecting the outer peripheral end of blade B, the angle θ5 is preferably approximately equal to θ4. When requirement (viii) is satisfied, the vortexes generated between the blades of the classifying rotor rotating at high speed are pushed further outward, which is preferable because it improves the yield.

[0037] R is not particularly limited and can be set appropriately depending on the dimensions of the classification device and the amount of particles to be treated, and can be, for example, 60 mm to 200 mm, 60 mm to 120 mm, or 100 mm to 200 mm. L1 is not particularly limited and can be set appropriately depending on the dimensions of the classification device and the amount of particles to be processed, and can be set to, for example, 30 mm to 70 mm or 40 mm to 120 mm. L2 is not particularly limited and can be set appropriately depending on the dimensions of the classification device and the amount of particles to be processed, for example, 40 mm to 90 mm or 60 mm to 170 mm. L3 is not particularly limited and can be set appropriately depending on the dimensions of the classification device and the amount of particles to be processed, and can be set to, for example, 40 mm to 90 mm or 60 mm to 170 mm. L4 is not particularly limited and can be set appropriately depending on the dimensions of the classification device and the amount of particles to be processed, and can be set to, for example, 60 mm to 170 mm or 100 mm to 200 mm.

[0038] The means for manufacturing the classification rotor is not particularly limited, but examples include a method in which each part is made and then assembled by welding; a method using a metal 3D printer in which metal powder is melted and solidified by laser irradiation to output a structure; a die-casting method in which a metal mold is made and molten metal such as an aluminum alloy is injected into the metal mold at high pressure to form a shape; and an investment casting method in which an evaporative model made with a 3D printer is covered with refractory material and evaporated in the mold by applying heat from the outside, and metal is then poured into the resulting cavity.

[0039] In general, manufacturing by welding and die-casting methods have the advantage of high dimensional accuracy but are known to have the disadvantage of long production times, while using metal 3D printers and lost-lose casting methods have the advantage of being able to handle complex shapes and have short delivery times but are known to have the disadvantage of being limited in production size. The manufacturing method for the classification rotor should be selected appropriately, taking into consideration the advantages and disadvantages of each manufacturing method, as well as the dimensions, accuracy, and delivery time required for the desired classification rotor.

[0040] The toner classifier is not particularly limited as long as it has the classification rotor for removing fine powder from the particles to be classified, and for example, the toner classifier body may have a supply means for supplying the particles to be classified, a means for collecting the classified material after classification, etc. As the particle size of the particles to be classified becomes smaller, the number of particles per unit mass increases, and therefore the number of contact points between particles increases, making it easier for agglomerates to form. From the viewpoint of being able to proceed with the classification process while breaking up these agglomerates, the toner classifier is configured as shown in Figure 3. a cylindrical main body casing; The classifying rotor 31; a cylindrical guide means 36 installed in a state in which at least a part of the classification rotor is covered; a particle inlet 34 to be classified and a particle supply means 35 having the particle inlet 34 to be classified, both formed on the side of the main casing for introducing particles to be classified; a fine powder discharge port 39 and a classified particle extraction port 37 formed on a side surface of the main casing for discharging the classified particles from which fine powder has been removed outside the main casing; A rotor attached to a central rotating shaft within the main casing, the rotor having a dispersion hammer (for example, a square block) 33 on the side of the rotor facing the classifying rotor 31. 32 and The main body casing and the guide means 36 are not limited to a cylindrical shape, but may have any shape.

[0041] It is believed that the presence of the guiding means 36 generates an ascending air current toward the classifying rotor 31 in the first space A, and a descending air current toward the dispersing rotor 32 in the second space B, making it possible to carry out the classification process while breaking down agglomerates of the particles to be classified by the dispersing hammer 33. The dispersing hammer 33 is not limited to a square block, and can have any shape as long as it is capable of breaking down agglomerates of the particles to be classified.

[0042] From the viewpoint of improving the flowability of the toner by increasing the average circularity of the toner, it is more preferable to have a liner 38 fixedly disposed around the dispersion rotor 32 while maintaining a gap therebetween. The liner 38 preferably has grooves on the surface facing the dispersion rotor 32.

[0043] It is believed that when the particles to be classified collide with the rotating dispersion hammer or the surface of the liner facing the dispersion hammer, the convex parts of the particles to be classified are crushed, resulting in an increase in average circularity. If the fine powder removal efficiency during classification is low, a state in which a large number of particles to be classified remain in the casing compared to when the fine powder removal efficiency is high may result in a decrease in the effect of improving the average circularity of the particles.

[0044] The total number of blades in the classification rotor (the sum of the number of blades A and the number of blades B) is not particularly limited and can be set appropriately depending on the dimensions of the classification rotor and the classification device, the amount of particles to be processed, etc., and can be, for example, 20 to 80. The number of blades A in the classification rotor is also not particularly limited and can be set appropriately depending on the dimensions of the classification rotor and the classification device, the amount of particles to be processed, etc., and can be, for example, 10 to 40. The number of blades B in the classification rotor is also not particularly limited and can be set appropriately depending on the dimensions of the classification rotor and the classification device, the amount of particles to be processed, etc., and can be, for example, 10 to 40.

[0045] The height of the blades of the classification rotor is not particularly limited and can be set appropriately depending on the dimensions of the classification rotor and classification device, the amount of particles to be treated, etc., and can be, for example, 50 mm to 100 mm. The height of the opening of the classification rotor is also not particularly limited and can be set appropriately depending on the dimensions of the classification rotor and classification device, the amount of particles to be treated, etc., and can be, for example, 50 mm to 100 mm.

[0046] The spacing between the blades arranged on the classification rotor at their outer peripheral ends is not particularly limited, and can be set appropriately depending on the dimensions of the classification rotor and classification device, the amount of particles to be treated, and the like.

[0047] For example, the distance between the outer peripheral ends of blades A and B arranged on the classification rotor is preferably 5.0 mm to 25.0 mm. If the distance is 25.0 mm or less, the vortex of the airflow generated between blades A and B arranged on the classification rotor is less likely to become too large. Furthermore, if the distance is 5.0 mm or more, it is possible to prevent the opening from becoming narrower, thereby preventing the time required for processing from becoming longer. The distance is more preferably 10.0 mm to 20.0 mm.

[0048] The dimensions of the main casing of the classification device, such as the height and inner diameter, are not particularly limited and can be set appropriately depending on the dimensions of the classification rotor and the amount of particles to be processed. The height of the main casing can be, for example, 150 mm to 500 mm. For example, a main body casing of 150 mm to 500 mm can be used as the main body casing in the classification device of the present disclosure.

[0049] The toner classifier can be applied to powder particles obtained by known manufacturing methods such as melt-kneading pulverization, suspension polymerization, emulsion aggregation, and dissolution suspension, but is particularly suitable for use in the melt-kneading pulverization method, since fine powder is likely to be generated when reducing the particle size of the toner. The procedure for manufacturing toner by the melt-kneading pulverization method will be described below, but the method is not limited to the following procedure.

[0050] <Method of manufacturing toner particles> First, in the raw material mixing process, a predetermined amount of at least the binder resin is weighed, blended, and mixed as the toner raw materials. If necessary, colorants, release agents to suppress hot offset during toner heat fixation, dispersants to disperse the release agents, charge control agents, etc. may also be mixed. Examples of mixing devices include double-con mixers, V-type mixers, drum mixers, super mixers, Henschel mixers, and Nauta mixers.

[0051] Furthermore, in the melt-kneading step, the toner raw materials blended and mixed in the raw material mixing step are melt-kneaded to melt the resins and disperse the colorant therein. In the melt-kneading step, for example, a batch-type kneader such as a pressure kneader or a Banbury mixer, or a continuous kneader can be used. In recent years, single-screw or twin-screw extruders have become mainstream due to their advantages such as continuous production. For example, a KTK twin-screw extruder manufactured by Kobe Steel, Ltd., a TEM twin-screw extruder manufactured by Toshiba Machine Co., Ltd., a twin-screw extruder manufactured by KCK Corporation, or a Co-kneader manufactured by Buss Co., Ltd. are commonly used.

[0052] Furthermore, the melt-kneaded product obtained by melt-kneading the toner raw materials is rolled with a two-roll mill or the like after melt-kneading, and then cooled through a cooling step in which the mixture is cooled with water or the like.

[0053] The cooled molten mixture obtained in the cooling step is then pulverized to a desired particle size in a pulverization step. In the pulverization step, the mixture is first coarsely pulverized using a crusher, hammer mill, feather mill, or the like. Then, the mixture is finely pulverized using a mechanical pulverizer such as an Inomizer (manufactured by Hosokawa Micron Corporation), a Kryptron (manufactured by Kawasaki Heavy Industries, Ltd.), a Super Rotor (manufactured by Nisshin Engineering Inc.), or a Turbo Mill (manufactured by Turbo Kogyo Co., Ltd.) to obtain a finely pulverized product. In this way, the mixture is pulverized stepwise to a predetermined toner particle size in the pulverization step.

[0054] The finely pulverized material obtained in the pulverization step is used as particles to be classified, and the particles to be classified are subjected to a classification process (classification step) using a toner classifier, thereby obtaining toner particles.

[0055] The obtained toner particles may be used as they are, but in order to impart functionality required of the toner, inorganic fine particles such as silica may be added to the toner particles as necessary, and then the toner may be subjected to a thermal sphering treatment or the like to produce a toner.

[0056] To improve the transferability of the toner, the average circularity of the toner is preferably 0.955 or more, more preferably 0.960 or more, and from the viewpoint of suppressing cleaning defects, the average circularity is preferably 0.990 or less.

[0057] From the viewpoint of improving the quality of images formed with the toner, the weight average particle diameter of the toner is preferably small, specifically, preferably 3.50 μm to 6.00 μm, more preferably 3.50 μm to 5.00 μm. Although a small weight average particle diameter of the toner is preferred, if it is 3.50 μm or more, it is less likely to slip through the cleaning blade and cause image defects.

[0058] The percentage by number of particles of 3.0 μm or less in the toner is preferably 20.0% by number or less, more preferably 15.0% by number or less, and even more preferably 10.0% by number or less.

[0059] <Toner raw materials> The raw materials of the toner, which contain at least the binder resin, will be described.

[0060] <Binder resin> As the binder resin, a general resin can be used, and examples thereof include polyester resin, styrene-acrylic acid copolymer, polyolefin resin, vinyl resin, fluororesin, phenol resin, silicone resin, and epoxy resin. Among these, amorphous polyester resin is preferred from the viewpoint of improving low-temperature fixability. Note that, from the viewpoint of achieving both low-temperature fixability and hot offset resistance, a low-molecular-weight polyester resin and a high-molecular-weight polyester resin may be used in combination.

[0061] From the viewpoint of further improving the low-temperature fixability and the blocking resistance during storage, a crystalline polyester resin can also be used as a plasticizer.

[0062] <Coloring agent> The toner raw materials may contain a colorant. Examples of the colorant that may be contained in the toner raw materials include the following. The colorant may be used alone or in combination of two or more.

[0063] Examples of the colorant include known organic pigments or oil-based dyes, carbon black, and magnetic materials.

[0064] Examples of cyan colorants include copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, and basic dye lake compounds.

[0065] Examples of magenta colorants include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds.

[0066] Examples of yellow colorants include condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds.

[0067] Examples of black colorants include carbon black, magnetic materials, and those toned to black using the above-mentioned yellow colorants, magenta colorants, and cyan colorants.

[0068] <Release agent> If necessary, a release agent may be used to suppress the occurrence of hot offset during the heat fixing of the toner. Typical examples of the release agent include low-molecular-weight polyolefins, silicone wax, fatty acid amides, ester waxes, carnauba wax, and hydrocarbon waxes.

[0069] The methods for measuring various physical properties of the toner and raw materials are described below. <Method for measuring weight average particle size (D4) of toner> The weight-average particle size (D4) of the toner was measured using a precision particle size distribution measuring device, the Coulter Counter Multisizer, equipped with a 100 μm aperture tube and the electrical resistance method. 3" (registered trademark, manufactured by Beckman Coulter), and measurement condition setting and measurement data analysis The accompanying dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter) is used to measure an effective number of 25,000 channels, analyze the measurement data, and perform calculations.

[0070] The aqueous electrolyte solution used for the measurement is prepared by dissolving special grade sodium chloride in ion-exchanged water to a concentration of approximately 1% by mass, such as "ISOTON II" (manufactured by Beckman Coulter).

[0071] Before carrying out measurements and analysis, the dedicated software is set up as follows.

[0072] In the "Change Standard Measurement Method (SOM)" screen of the dedicated software, set the total count in control mode to 50,000 particles, the number of measurements to 1, and the Kd value to the value obtained using "Standard Particle 10.0 μm" (Beckman Coulter). Press the threshold / noise level measurement button to automatically set the threshold and noise level. Also, set the current to 1600 μA, the gain to 2, the electrolyte to ISOTON II, and check "Flush aperture tube after measurement."

[0073] In the dedicated software's "Pulse to particle size conversion setting screen," set the bin interval to logarithmic particle size, the particle size bin to 256 particle size bins, and the particle size range to 2 μm or more and 60 μm or less.

[0074] The specific measurement method is as follows. (1) Pour approximately 200 ml of the electrolyte solution into a 250 ml round-bottom glass beaker made specifically for the Multisizer 3, set it on the sample stand, and stir the stirrer rod counterclockwise at 24 revolutions per second. Then, use the "aperture tube flush" function of the analysis software to remove any dirt or air bubbles from inside the aperture tube.

[0075] (2) Approximately 30 ml of the above-mentioned aqueous electrolyte solution is placed in a 100 ml flat-bottom glass beaker, and approximately 0.3 ml of a dilution obtained by diluting "Contaminon N" (a 10% by weight aqueous solution of a neutral detergent for cleaning precision measuring instruments, pH 7, consisting of a nonionic surfactant, anionic surfactant, and organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) three times by weight with ion-exchanged water is added as a dispersant.

[0076] (3) A predetermined amount of ion-exchanged water is placed in the water tank of an ultrasonic disperser, "Ultrasonic Dispersion System Tetora150" (manufactured by Nikkaki Bios Co., Ltd.), which has two built-in oscillators with an oscillation frequency of 50 kHz and a phase difference of 180 degrees and an electrical output of 120 W, and approximately 2 ml of the Contaminon N is added to this water tank.

[0077] (4) Set the beaker (2) in the beaker fixing hole of the ultrasonic disperser, operate the ultrasonic disperser, and adjust the height of the beaker so that the resonance state of the liquid surface of the electrolytic solution in the beaker is maximized.

[0078] (5) While the electrolyte solution in the beaker in (4) is being irradiated with ultrasonic waves, approximately 10 mg of toner is added little by little to the electrolyte solution and dispersed. The ultrasonic dispersion process is then continued for another 60 seconds. During the ultrasonic dispersion, the water temperature in the water tank is appropriately adjusted to be between 10°C and 40°C.

[0079] (6) Using a pipette, add the electrolyte solution (5) containing the dispersed toner to the round-bottom beaker (1) placed in the sample stand, and adjust the measurement concentration to approximately 5%. Then, measure the particle count until it reaches 50,000 particles.

[0080] (7) The measurement data is analyzed using the dedicated software attached to the device, and the weight average particle size (D4) is calculated. When the dedicated software is set to Graph / Volume %, the "Average diameter" on the Analysis / Volume Statistics (Arithmetic Mean) screen is the weight-average particle diameter (D4).

[0081] <Measuring method for the percentage of toner particles 3.0 μm or smaller> In step (7) of the method for measuring the weight-average particle diameter (D4) of toner, when the graph / number % is set using the dedicated software, the cumulative number % in the particle diameter range of 3.0 μm or less is the number % of particles of 3.0 μm or less.

[0082] <Method for measuring average circularity> The average circularity of the toner is measured using a flow particle image analyzer "FPIA-3000" (manufactured by Sysmex Corporation) under the measurement and analysis conditions used during the calibration process.

[0083] The specific measurement method is as follows. First, approximately 20 ml of ion-exchanged water, from which impurities such as solids have been removed, is placed in a glass container. Approximately 0.2 ml of a solution prepared by diluting Contaminon N (a 10% by weight aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) approximately three times by weight with ion-exchanged water is added. Approximately 0.02 g of the sample to be measured is then added, and the mixture is dispersed for two minutes using an ultrasonic disperser to obtain a dispersion for measurement. The dispersion is then cooled appropriately so that its temperature is between 10°C and 40°C. A tabletop ultrasonic cleaner disperser (VS-150, manufactured by Vervoclear) with an oscillation frequency of 50 kHz and an electrical output of 150 W is used as the ultrasonic disperser. A predetermined amount of ion-exchanged water is placed in the water tank, and approximately 2 ml of Contaminon N is added to the water tank.

[0084] The measurement was performed using the flow particle image analyzer equipped with a standard objective lens (10x magnification), and a particle sheath "PSE-900A" (manufactured by Sysmex Corporation) was used as the sheath liquid. The dispersion prepared according to the procedure described above was introduced into the flow particle image analyzer, and 3,000 toner particles were measured in HPF measurement mode and total count mode. The binarization threshold for particle analysis was set to 85%, and the analyzed particle diameter was limited to a circle-equivalent diameter of 1.985 μm or more and less than 39.69 μm, and the average circularity of the toner particles was determined.

[0085] Before starting the measurement, automatic focus adjustment is performed using standard latex particles (Duke Scientific's "RESEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5200A" diluted with ion-exchanged water). After that, it is preferable to perform focus adjustment every two hours from the start of the measurement.

[0086] In the examples of the present application, a flow-type particle image analyzer was used that had been calibrated by Sysmex Corporation and had a calibration certificate issued by Sysmex Corporation. Measurements were carried out under the same measurement and analysis conditions as when the calibration certificate was received, except that the particle diameters to be analyzed were limited to equivalent-circle diameters of 1.985 μm or more and less than 39.69 μm. [Example]

[0087] Hereinafter, the present disclosure will be described in more detail using examples and comparative examples, but the aspects of the present disclosure are not limited thereto. Hereinafter, the number of parts in the examples and comparative examples is based on parts by mass unless otherwise specified.

[0088] <Example of binder resin production> Polyoxypropylene (2.2)-2,2-bis(4-hydroxyphenyl)propane: 72.0 parts (100 mol% based on the total number of moles of polyhydric alcohol) Terephthalic acid: 28.0 parts (96 mol% based on the total number of moles of polycarboxylic acids) Tin 2-ethylhexanoate (esterification catalyst): 0.5 parts

[0089] The above materials were weighed and placed in a reaction vessel equipped with a condenser, a stirrer, a nitrogen inlet, and a thermocouple. The atmosphere in the flask was then replaced with nitrogen gas, and the temperature was gradually increased while stirring. The reaction was continued for 8 hours at 220°C. The pressure in the reaction vessel was then reduced to 8.3 kPa and maintained at this temperature for 1 hour. The vessel was then cooled to 180°C and returned to atmospheric pressure.

[0090] Trimellitic anhydride: 1.3 parts (4 mol% based on the total number of moles of polycarboxylic acids) tert-butylcatechol (polymerization inhibitor): 0.1 parts

[0091] The above materials were then added, the pressure in the reaction vessel was reduced to 8.3 kPa, and the reaction was carried out for 1 hour while maintaining the temperature at 180°C, to obtain a binder resin (amorphous polyester resin).The softening point of the obtained binder resin, measured in accordance with ASTM D36-86, was 110°C.

[0092] <Example of manufacturing pulverized particles for toner (particles to be classified)> 90 parts binder resin Fischer-Tropsch wax (hydrocarbon wax, melting point 90°C) 5 parts CI Pigment Blue 15:3 5 parts

[0093] The above materials were mixed in a Henschel mixer (FM-75 model, manufactured by Mitsui Mining Co., Ltd.) at a rotation speed of 20 s -1 After mixing for 5 minutes, the mixture was kneaded in a twin-screw kneader (PCM-30 model, manufactured by Ikegai Corporation). The barrel temperature during kneading was set so that the outlet temperature of the kneaded product was 120°C. The outlet temperature of the kneaded product was directly measured using a handy thermometer HA-200E manufactured by Anritsu Meter Co., Ltd. The kneaded product obtained was cooled and coarsely pulverized in a pin mill to a volume average particle size of 100 μm or less to obtain a coarsely pulverized product.

[0094] The coarsely crushed material was pulverized using a mechanical pulverizer (Turbo Kogyo Co., Ltd., Turbo Mill T250-CRS, rotor shape RS type) at a rotor rotation speed of 11,000 rpm and a pulverization feed rate of 10 kg / h to obtain a finely crushed material. The finely crushed material 1 was then pulverized at a rotor rotation speed of 12,000 rpm and a pulverization feed rate of 10 kg / h to obtain pulverized particles for toner (particles to be classified). The weight-average particle size of the pulverized particles for toner 1 was 4.62 μm, the number percentage of particles 3.0 μm or less was 39.6%, and the average circularity was 0.951.

[0095] <Toner classifier> The toner classifier used was the one shown in Figure 3. a cylindrical main body casing; The main body casing includes a rotating body attached to a central rotating shaft, a disk-shaped dispersion rotor 32 having a plurality of dispersion hammers 33 on a side surface of the rotor facing the classification rotor, and rotating at high speed; a liner 38 spaced apart from the periphery of the dispersion rotor 32; a classification rotor 31 which is a means for classifying particles to be classified; a fine powder discharge port 39 for discharging and removing fine powder having a predetermined particle size or less selected by the classifying rotor 31; A cold air inlet (not shown) for introducing cold air from the bottom of the dispersion rotor; a particle supply port 34 for introducing particles to be classified into the main casing, and a particle supply means 35 having the particle inlet 34; a powder discharge port 37 for discharging the classified particles after classification; A cylindrical guide is installed so that at least a part of the classification rotor 31 is covered. Means 36 and It is composed of:

[0096] The guide means 36 divides the space of the main casing within the toner classifier into space A, where an airflow is generated in the direction of introducing the particles to be treated into the classifying rotor 31, and space B, where an airflow is generated in the direction of introducing the particles to be treated between the dispersing rotor 32 and the liner 38.

[0097] The fine powder discharge port 39 communicates with fine powder recovery means (cyclone) 40 for recovering the discharged fine powder, and is connected to a blower 41 that communicates with the fine powder recovery means 40. The blower 41 can be used to generate an airflow that flows from the outside to the inside of the classifying rotor 31. A static pressure gauge 42 is also installed to measure the pressure inside the main casing (static pressure on the inlet side of the classifying device) and the pressure at the fine powder discharge port (static pressure on the outlet side of the classifying device).

[0098] If the Δstatic pressure before and after the classifier is low under the same classification conditions, such as the blower air volume and rotor rotation speed, and only the shape of the classifier rotor is different, it can be considered that the pressure loss inherent to the classifier rotor is low. If the pressure loss due to the classifier is small, this is preferable from the viewpoint of keeping the load on the blower low when the air volume required for classification is output.

[0099] The height of the main casing space was 300 mm, and the inner diameter was 300 mm. The outer diameter of the dispersion rotor was 285 mm, and eight dispersion hammers were attached to the dispersion rotor as shown in Figure 4. The length, width, and height of the dispersion hammers were 30 mm, 20 mm, and 20 mm, respectively.

[0100] As shown in Figure 5, the cylindrical guide means is connected to a guide means support member 51, and can be installed at any position by connecting the guide means support member to the main casing with screws, etc. The diameter of the guide means is 250 mm, the height is 210 mm, and the distance between the top end of the guide means and the top end of the casing is 40 mm.

[0101] <liner> Liner 1 had multiple convex portions and concave portions formed between the convex portions as shown in Figure 6, the shape of the concave portions was triangular, the repeat distance between the convex portions was 3 mm, the depth of the concave portions was 3.0 mm, and the height of the liner was 50 mm. Liner 2 was a liner 1 with the concave and convex surfaces removed and a smooth surface.

[0102] <Classification rotors 1 to 20 used in the examples> The classification rotor 1 has the shape shown in Figure 7. One blade A included in the first blade set was placed between two adjacent blades B included in the second blade set. The first blade set (blade A) had 16 blades, and the second blade set (blade B) had 16 blades. R was 92 mm, L1 was 40 mm, L2 was 66 mm, L3 was 66 mm, L4 was 86 mm, θ1 was 60°, θ2 was 30°, θ3 was 60°, θ4 was 10°, θ5 was 10°, and the height of the opening of the classification rotor was 70 mm.

[0103] Classification rotors 2 and 5 have the shapes shown in Figure 7. Differences between classification rotors 2 and 5 and classification rotor 1 are shown in Table 1.

[0104] The classifying rotor 3 has the shape shown in Figure 8. One blade A included in the first blade set was arranged between two adjacent blades B included in the second blade set. The first blade set (blade A) had 18 blades, and the second blade set (blade B) had 18 blades.

[0105] The classification rotor 4 has the shape shown in Figure 9. One blade A included in the first blade set was arranged between two adjacent blades B included in the second blade set. The first blade set (blade A) had 14 blades, and the second blade set (blade B) had 14 blades.

[0106] The classification rotor 6 has the shape shown in Figure 1. One blade A included in the first blade set was arranged between two adjacent blades B included in the second blade set. The first blade set (blade A) had 16 blades, and the second blade set (blade B) had 16 blades. R was 92 mm, L1 was 40 mm, L2 was 66 mm, L3 was 66 mm, θ1 was 60°, θ2 was 30°, θ3 was 60°, and the height of the opening of the classification rotor was 70 mm.

[0107] The classifying rotors 7 and 11 to 20 have the shapes shown in Figure 1. The differences between the classifying rotors 7 and 11 to 20 and the classifying rotor 6 are shown in Table 1.

[0108] The classifying rotor 8 has a shape shown in FIG. One blade A included in the first blade set was arranged between two adjacent blades B included in the second blade set. The first blade set (blade A) had 15 blades, and the second blade set (blade B) had 15 blades. R was 92 mm, L1 was 40 mm, L2 was 66 mm, L3 was 66 mm, θ1 was 60°, θ2 was 30°, θ3 was 60°, and the height of the opening of the classification rotor was 70 mm.

[0109] The classification rotor 9 has the shape shown in Figure 11. Two blades A included in the first blade set were arranged between two adjacent blades B included in the second blade set. The first blade set (blade A) had 22 blades, and the second blade set (blade B) had 11 blades. R was 92 mm, L1 was 40 mm, L2 was 66 mm, L3 was 66 mm, θ1 was 60°, θ2 was 30°, θ3 was 60°, and the height of the opening of the classification rotor was 70 mm.

[0110] The classification rotor 10 has the shape shown in Figure 12. Three blades A included in the first blade set were arranged between two adjacent blades B included in the second blade set. The first blade set (blade A) had 24 blades, and the second blade set (blade B) had 8 blades. R was 92 mm, L1 was 40 mm, L2 was 66 mm, L3 was 66 mm, θ1 was 60°, θ2 was 30°, θ3 was 60°, and the height of the opening of the classification rotor was 70 mm.

[0111] <Comparative Rotors 1 to 10 used in Comparative Examples> Comparative rotor 1 has the shape shown in Figure 13. R was 92 mm, L3 was 66 mm, θ1 was 60°, and the height of the opening of the classification rotor was 70 mm.

[0112] Comparative rotor 2 has the shape shown in Figure 14. R was 92 mm, L1 was 40 mm, L2 was 66 mm, θ2 was 30°, θ3 was 60°, and the height of the opening of the classification rotor was 70 mm.

[0113] Comparative rotors 3 to 9 have the shapes shown in Figure 1. Differences between comparative rotors 3 to 9 and the classification rotor 6 are shown in Table 1.

[0114] The comparative rotor 10 has the shape shown in Figure 15. Four blades A included in the first blade set were arranged between two adjacent blades B included in the second blade set. The first blade set (blade A) had 24 blades, and the second blade set (blade B) had 6 blades. R was 92 mm, L1 was 40 mm, L2 was 66 mm, L3 was 66 mm, θ1 was 60°, θ2 was 30°, θ3 was 60°, and the height of the opening of the classification rotor was 70 mm.

[0115] [Table 1]

[0116] <Examples 1 to 22 and Comparative Examples 1 to 10> The toner classifier was fitted with the classification rotor 1 and liner 1, with the classification rotor rotation speed set to 9000 rpm, the dispersion rotor rotation speed set to 5000 rpm, and the blower air volume set to 10.0 m 3 Toner 1 was obtained by 60 cycles of classification under the conditions of a speed of 10 s / min, a classification cycle of 60 s (time for adding particles to be classified: 10 s, time for classification treatment: 30 s, time for collecting classified particles after treatment: 20 s), toner pulverized particles 1 as the particles to be classified, and an amount of particles to be classified added per cycle of 200 g. In addition, by changing the conditions as shown in Table 2, toners 2 to 22 and comparative toners 1 to 10 were obtained. Furthermore, the weight average particle diameter D4, the percentage of particles 3.0 μm or less, and the average circularity of the toner were measured by the above-mentioned measuring means. The classification yield was also calculated from the input amount of particles to be classified (200 g × 60 cycles) and the mass of the obtained toner. Furthermore, under each classification condition, the static pressure on the outlet side of the classification rotor before the particles to be classified (during idle operation) was subtracted from the static pressure on the inlet side of the classification rotor to calculate the Δstatic pressure before and after the classification rotor. In this case, the side closer to the blower, i.e., the outlet side of the classification rotor that communicates with the blower, has a more negative pressure than the inlet side of the classification rotor (the side that communicates with the inlet for particles to be classified), so the Δstatic pressure is a positive value. The evaluation results are summarized in Table 2.

[0117] <Evaluation 1: Yield evaluation criteria> A: Yield 70.0% or more B: Yield 60.0% or more, less than 70.0% C: Yield 50.0% or more, less than 60.0% D: Yield 45.0% or more and less than 50.0% E: Yield less than 45.0%

[0118] <Evaluation criteria for evaluation 1-3: % of particles 3.0 μm or smaller> A: Less than 10.0% by number B: 10.0% or more by number, less than 15.0% by number C: 15.0% or more by number, less than 20.0% by number D: 20.0% or more by number, less than 25.0% by number E: 25.0% or more

[0119] <Evaluation 2: Evaluation criteria for Δ static pressure before and after the classification rotor> A: Less than 7.20 kPa B: 7.20kPa or more, less than 7.60kPa C: 7.60kPa or more, less than 8.00kPa D: 8.00 kPa or more, less than 8.40 kPa E: 8.40kPa or more

[0120] <Overall rating> A: All items were ranked A (very good) B: At least one item was ranked B in the lowest category (excellent) C: At least one item was ranked C in the lowest category. D: At least one item was ranked D (not acceptable for this disclosure) E: There was at least one item that was ranked E (not acceptable for this disclosure)

[0121] <Reference evaluation: average circularity> A: Average circularity 0.960 or more B: Average circularity 0.955 or more and less than 0.960 C: Average circularity less than 0.955

[0122] [Table 2] [Explanation of symbols]

[0123] 31. Classification rotor, 32. Dispersion rotor, 33. Dispersion hammer, 34. Inlet for particles to be classified, 35. Means for supplying particles to be classified, 36. Guide means, 37. Inlet for extracting classified material, 38. Liner, 39. Fine powder outlet, 40. Means for recovering fine powder (cyclone), 41. Blower, 42. Static pressure gauge, 51. Support member for guide means

Claims

1. A toner classifying device equipped with a classification rotor, The classification rotor has a plurality of blades extending from the rotation center side to the outer periphery side of the classification rotor, The plurality of blades are arranged at predetermined intervals from one another, the gap forms an opening facing the rotation center region of the classification rotor; The plurality of blades includes a first blade group consisting of blade A and a second blade group consisting of blade B having a length longer than that of blade A, The blades A have approximately the same length and are arranged at intervals so that they trace approximately the same trajectory when the classifying rotor rotates. The blades B have approximately the same length and are arranged at intervals so that they trace approximately the same trajectory when the classifying rotor rotates. the number of blades A arranged between two adjacent blades B is independently 1 to 3, The blade B has a first bent portion, the blades A and B are provided so as to be positioned upstream in the rotation direction of the classification rotor from the end of the classification rotor on the rotation center side toward the end of the classification rotor on the outer periphery side, the distance between the rotation center of the classification rotor and the outer peripheral end of the blade A is approximately equal to the distance between the rotation center of the classification rotor and the outer peripheral end of the blade B, a distance between the rotation center of the classification rotor and the end of the blade A on the rotation center side is approximately equal to a distance between the rotation center of the classification rotor and the first bent portion of the blade B; the distance between the rotation center of the classification rotor and the end of the blade A on the rotation center side is greater than the distance between the rotation center of the classification rotor and the end of the blade B on the rotation center side; In a cross section of the classification rotor cut in a direction perpendicular to the rotation axis of the classification rotor, (i) the angle θ1 (°) formed by a line connecting the rotation center of the classification rotor and the end of the blade A on the rotation center side and a portion of the blade A closer to the outer periphery than the end of the rotation center side is 40° to 65°, (ii) the angle θ3 (°) formed by the line connecting the rotation center of the classification rotor and the first bent portion of the blade B and the portion of the blade B closer to the outer periphery than the first bent portion is approximately the same as the angle θ1; (iii) the angle θ2 (°) formed by the line connecting the rotation center of the classification rotor and the first bend portion of the blade B and the line connecting the end of the rotation center side of the blade B and the first bend portion of the blade B is 0°≦θ2≦θ3×1 / 2 Fulfilling (iv) When the radius of the classification rotor is R and the distance between the rotation center of the classification rotor and the end of the blade B on the rotation center side is L1, R and L1 are 0.35≦L1 / R≦0.65 Fulfilling (v) When the distance between the rotation center of the classification rotor and the first bend portion of the blade B is L2, R, L1 and L2 are 0.35≦(L2-L1) / (R-L1)≦0.70 A toner classification device, characterized by satisfying the above.

2. The blade A has a bent portion, (vi) When the distance from the rotation center of the classification rotor to the end of the blade A on the rotation center side is L3 and the distance from the rotation center of the classification rotor to the bent portion of the blade A is L4, 0.65≦(L4-L3) / (R-L3)≦0.85 The toner classification device according to claim 1 , wherein the above formula (1) is satisfied.

3. The blade A has a bent portion, (vii) The toner classification device according to claim 1 or 2, wherein an angle θ4 formed by a line connecting the end of the blade A on the rotation center side and the bent portion of the blade A and a line connecting the bent portion of the blade A and the end of the blade A on the outer periphery side is 5° to 25°.

4. The blade A has a bent portion, (viii) the blade B has a second bent portion on the outer circumferential side of the first bent portion, a distance L4 between the rotation center of the classification rotor and the bent portion of the blade A and a distance L5 between the rotation center of the classification rotor and the second bent portion of the blade B are approximately equal, 4. The toner classification device according to claim 1, wherein an angle θ5 formed by a line connecting the bent portion of blade B and the second bent portion of blade B and a line connecting the second bent portion of blade B and the outer peripheral end of blade B is approximately equal to an angle θ4 formed by a line connecting the end of blade A closer to the rotation center and the bent portion of blade A and a line connecting the bent portion of blade A and the outer peripheral end of blade A.

5. 5. The toner classifying device according to claim 1, wherein the distance between the blade A and the blade B at their outer peripheral ends is 5.0 mm to 25.0 mm.

6. A main body casing; a guide means installed in a state in which at least a part of the classification rotor is covered; a particle inlet formed on a side surface of the main casing for introducing particles to be classified, and particle supply means having the particle inlet; a classified particle extraction port formed on a side surface of the main casing for discharging the classified particles from which fine powder has been removed outside the main casing; a dispersion rotor attached to a central rotation shaft within the main body casing, the dispersion rotor being a rotating body having dispersion hammers on a side surface of the rotor facing the classification rotor; The toner classifying device according to any one of claims 1 to 5, further comprising:

7. 7. The toner classifying device according to claim 6, further comprising a liner fixedly disposed around the periphery of the dispersion rotor with a gap maintained therebetween.

8. 8. The toner classifying device according to claim 7, wherein the liner has a surface facing the dispersion rotor, the surface being provided with grooves.

9. A toner manufacturing method including a classification step of classifying particles to be classified using a toner classifier, A method for producing toner, wherein the toner classifying device is the toner classifying device according to any one of claims 1 to 8.

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