Toner classification equipment and toner production method

Abstract

A toner classification device and a toner production method. The toner classification device includes a classification rotor having a blade A extending from the rotational center of the classification rotor toward the outer periphery of the classification rotor and a blade B having a length longer than the blade A, wherein the blade A and the blade B are arranged to satisfy a predetermined relationship. The toner production method includes a classification step in which particles to be classified are classified using the toner classification device.

Description

Technical Field

[0001] The present disclosure relates to a toner classifying apparatus used in an electrophotographic system, an electrostatic recording system, and a toner ejection system, and to a toner production method. Background Art

[0002] In recent years, full-color electrophotographic copiers have become widely popular and have also begun to be used in the commercial printing market. The commercial printing market requires high speed, high image quality, and high productivity, while adapting to a wide range of media (paper types). Regarding toners, improved image quality can be pursued by stabilizing the developing and transfer properties, which is particularly based on the stable charging performance provided by toners with small particle sizes and sharp particle size distributions.

[0003] The melt-kneading / pulverization method is one of the commonly known methods for producing toner particles. 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 melt-kneaded, cooled and solidified, and then the kneaded product is micronized using a pulverizer to produce toner particles. If necessary, the toner particles are then classified to a desired particle size distribution, sphericalized using a heat treatment to adjust their circularity, and a fluidizing agent such as inorganic fine particles is added to produce the toner.

[0004] Various pulverizing devices are used as kneading pulverizing devices. For example, the mechanical pulverizing device described in Japanese Patent Application Laid-Open No. 2011-237816 is equipped with a housing having an inlet and an outlet for the material to be pulverized. Within this housing are a rotor supported on a central rotating shaft and having a plurality of protrusions and recesses on its outer circumferential surface; and a fixed element disposed outside the rotor with a predetermined gap therebetween and having a plurality of protrusions and recesses on its inner circumferential surface. As the material to be pulverized is carried by air from the inlet to the outlet and passes through the facing processing space of the rotor and fixed element, it is pulverized by impact with the protrusions and recesses of the rotor or fixed element.

[0005] Furthermore, particles with a diameter that is too small, which are generated during the pulverization step, are mixed into the pulverized material obtained by the pulverization process by a pulverization device to a desired particle size. When present in the toner, these particles with a diameter that is too small cause problems such as fogging in the electrophotographic process, and due to this problem, the particles with a diameter that is too small are generally removed by a classification process.

[0006] For example, the following are known colorant production methods with classification processing using a classification device: a colorant production method using an air flow classification device utilizing a Coanda effect described in Japanese Patent Publication No. 2001-201890, and a colorant production method using a centrifugal wind classifier described in Japanese Patent Publication No. 2008-26457.

[0007] When using a centrifugal air classifier, a pulverized material containing particles to be classified and derived from toner raw material kneading is transported from an inlet to the vicinity of the outer periphery of the classifying rotor by an air flow directed inward from the outer periphery of the classifying rotor. Due to the rotation of the classifying rotor, centrifugal force is applied to the outer periphery of the classifying rotor. The centrifugal force acting on the particles to be classified is a force directed to the outer side of the classifying rotor and is proportional to the weight of the particles. Therefore, the centrifugal force acting on the particles with too small diameters among the particles to be classified is less than the drag force applied by the air flow directed inward from the outer periphery of the classifying rotor. Therefore, classification is carried out in the following manner: the particles with too small diameters are removed from the particles to be classified through the passages between the blades of the classifying rotor and are recovered by a device for recovering the particles with too small diameters that is connected to the inner side of the classifying rotor, thereby obtaining a classified material, and a classified material recovery device arranged on the outer side of the classifying rotor is used to recover the classified material from which the particles with too small diameters have been removed.

[0008] Japanese Patent Application Laid-Open No. 2010-160374 also proposes a toner production method using a classifying device having multiple blades arranged on the same circumference with a specific intervening gap, and each blade forming an angle θ with respect to a straight line connecting the center of a classifying rotor and the blade's tip. The classifying device used in this production method generates eddy currents by separating air entering between the blades from the outside of a rapidly rotating classifying rotor into a component directed in the direction of the rotation center and a component discharged to the outside of the classifying rotor. Summary of the Invention

[0009] As described above, the classification process is performed by adjusting the balance between the drag force and centrifugal force acting on the particles to be classified. However, in some cases, particles that should not be drawn in as undersized particles are also mistakenly drawn in and removed. This occurs due to factors such as turbulence in the airflow within the classification equipment, agglomeration between the particles to be classified, changes in velocity when the particles to be classified approach the classification rotor, and eddy currents between the blades of the classification rotor. When the average particle size of the particles to be classified approaches the size of the undersized particles that should be removed by the classification step, the removal rate due to mistaken aspiration increases. As a result, when pursuing smaller toner particle sizes, the yield of the classification step is observed to decrease.

[0010] It is believed that the eddy currents generated in the toner production method described in Japanese Patent Application Laid-Open No. 2010-160374 are generated by the configuration along the blades. Compared to a classifying rotor arranged on the aforementioned radial straight line, when the angle θ is present, more eddy currents are generated on the outer side of the classifying rotor. As a result, the rate of incorrect aspiration of particles to be classified is reduced, and improved yield is observed. However, when the angle θ formed becomes too large, the spacing between the blades on the inner side of the classifying rotor becomes too small. Therefore, it has been determined that particles with excessively small diameters have difficulty passing between the blades. Consequently, there is a problem of insufficient removal of particles with excessively small diameters and increased pressure loss.

[0011] As described above, toner requires a smaller particle size to improve image quality. The main factor affecting the particle size of the toner finally obtained is the particle size of the pulverized material produced by the pulverization step after the mixture of the toner raw materials has been melt-kneaded. Thus, in order to reduce the particle size of the toner, the particle size of the pulverized material must be reduced. The classification step is a step for removing particles with too small a diameter, which may be a problem factor in the electrophotographic process. However, when the toner particle size is reduced, the average particle size of the pulverized material becomes close to the particle size of the particles with too small a diameter, which are the particles to be removed by the classification step. As a result, the problem of reduced yield arises due to the removal of particles that have a diameter suitable for the toner and should not be removed (partially as particles with too small a diameter).

[0012] Furthermore, when performing classification using a centrifugal air classifier, in order to prevent the capture of particles to be classified that should not be removed, it is conceivable to use means such as increasing the number of blades of the classifying rotor or increasing the angle θ formed with respect to a straight line connecting the center of the classifying rotor and the front end of each blade. However, in these cases, there arises a problem in that the pressure loss of the classifying rotor increases, thereby increasing the load on the blower.

[0013] The present disclosure solves the above-mentioned problems and provides a toner classifying apparatus and a toner production method that suppress pressure loss of a classifying rotor and exhibit excellent productivity even in the case of producing toner having a small particle size.

[0014] The present disclosure relates to a toner classification device, comprising:

[0015] Classifying rotor, where:

[0016] The classifying rotor includes a plurality of blades extending from the rotation center direction of the classifying rotor toward the outer circumference direction of the classifying rotor.

[0017] the plurality of blades being arranged with a defined gap established between the blades;

[0018] The gap forms an opening facing the rotation center area of the classifying rotor;

[0019] The plurality of blades include a first blade group consisting of blades A and a second blade group consisting of blades B, wherein the length of the blades B is longer than the length of the blades A.

[0020] The lengths of the blades A are substantially the same as each other, and the blades A are arranged at intervals in such a manner as to follow substantially the same paths as each other during rotation of the classifying rotor,

[0021] The lengths of the blades B are substantially the same as each other, and the blades B are arranged at intervals in such a manner as to follow substantially the same paths as each other during rotation of the classifying rotor,

[0022] The number of blades A arranged between two adjacent blades B is 1 to 3,

[0023] The blade B has a first bending portion,

[0024] The blades A and the blades B are arranged so that portions of the blades farther from the rotation center of the classifying rotor are located upstream in the rotation direction of the classifying rotor compared to portions of the blades closer to the rotation center of the classifying rotor.

[0025] The distance between the rotation center of the classifying rotor and the outer peripheral end of the blade A and the distance between the rotation center of the classifying rotor and the outer peripheral end of the blade B are substantially equal to each other.

[0026] The distance between the rotation center of the classifying rotor and the end of the blade A on the rotation center side and the distance between the rotation center of the classifying rotor and the first bent portion of the blade B are substantially equal to each other.

[0027] The distance between the rotation center of the classifying rotor and the end of the blade A on the rotation center side is greater than the distance between the rotation center of the classifying rotor and the end of the blade B on the rotation center side.

[0028] In a cross section obtained when the classifying rotor is cut in a direction perpendicular to the rotation axis of the classifying rotor,

[0029] i) an angle θ1 formed by a straight line connecting the rotation center of the classifying rotor and the end of the blade A on the rotation center side and a portion of the blade A closer to the outer circumference than the end of the blade A on the rotation center side is 40° to 65°, where the unit of the angle θ1 is degrees;

[0030] ii) An angle θ3 formed by a straight line connecting the rotation center of the classifying rotor and the first bent portion of the blade B and a portion of the blade B closer to the outer circumference than the first bent portion of the blade B is substantially equal to angle θ1, and the unit of angle θ3 is degrees.

[0031] iii) an angle θ2 formed by a straight line connecting the rotation center of the classifying rotor and the first bent portion of the blade B and a straight line connecting the end portion of the blade B on the rotation center side and the first bent portion of the blade B satisfies 0°≤θ2≤θ3×1 / 2, where the unit of the angle θ2 is degrees,

[0032] iv) when the radius of the classifying rotor is represented by R and the distance between the rotation center of the classifying rotor and the end portion on the rotation center side of the blade B is represented by L1, R and L1 satisfy 0.35≤L1 / R≤0.65, and

[0033] v) When the distance between the rotation center of the classifying rotor and the first bent portion of the blade B is represented by L2, R, L1, and L2 satisfy 0.35≤(L2-L1) / (R-L1)≤0.70.

[0034] The present disclosure also relates to a toner production method including a classification process of classifying particles to be classified by using a toner classification apparatus, wherein:

[0035] The toner classification device comprises:

[0036] Classifying rotor, where:

[0037] The classifying rotor includes a plurality of blades extending from the rotation center direction of the classifying rotor toward the outer circumference direction of the classifying rotor.

[0038] the plurality of blades being arranged with a defined gap established between the blades;

[0039] The gap forms an opening facing the rotation center area of the classifying rotor;

[0040] The plurality of blades include a first blade group consisting of blades A and a second blade group consisting of blades B, wherein the length of the blades B is longer than the length of the blades A.

[0041] The lengths of the blades A are substantially the same as each other, and the blades A are arranged at intervals in such a manner as to follow substantially the same paths as each other during rotation of the classifying rotor,

[0042] The lengths of the blades B are substantially the same as each other, and the blades B are arranged at intervals in such a manner as to follow substantially the same paths as each other during rotation of the classifying rotor,

[0043] The number of blades A arranged between two adjacent blades B is 1 to 3,

[0044] The blade B has a first bending portion,

[0045] The blades A and the blades B are arranged so that portions of the blades farther from the rotation center of the classifying rotor are located upstream in the rotation direction of the classifying rotor compared to portions of the blades closer to the rotation center of the classifying rotor.

[0046] The distance between the rotation center of the classifying rotor and the outer peripheral end of the blade A and the distance between the rotation center of the classifying rotor and the outer peripheral end of the blade B are substantially equal to each other.

[0047] The distance between the rotation center of the classifying rotor and the end of the blade A on the rotation center side and the distance between the rotation center of the classifying rotor and the first bent portion of the blade B are substantially equal to each other.

[0048] The distance between the rotation center of the classifying rotor and the end of the blade A on the rotation center side is greater than the distance between the rotation center of the classifying rotor and the end of the blade B on the rotation center side.

[0049] In a cross section obtained when the classifying rotor is cut in a direction perpendicular to the rotation axis of the classifying rotor,

[0050] i) an angle θ1 formed by a straight line connecting the rotation center of the classifying rotor and the end of the blade A on the rotation center side and a portion of the blade A closer to the outer circumference than the end of the blade A on the rotation center side is 40° to 65°, where the unit of the angle θ1 is degrees;

[0051] ii) An angle θ3 formed by a straight line connecting the rotation center of the classifying rotor and the first bent portion of the blade B and a portion of the blade B closer to the outer circumference than the first bent portion of the blade B is substantially equal to angle θ1, and the unit of angle θ3 is degrees.

[0052] iii) an angle θ2 formed by a straight line connecting the rotation center of the classifying rotor and the first bent portion of the blade B and a straight line connecting the end portion of the blade B on the rotation center side and the first bent portion of the blade B satisfies 0°≤θ2≤θ3×1 / 2, where the unit of the angle θ2 is degrees,

[0053] iv) when the radius of the classifying rotor is represented by R and the distance between the rotation center of the classifying rotor and the end portion on the rotation center side of the blade B is represented by L1, R and L1 satisfy 0.35≤L1 / R≤0.65, and

[0054] v) When the distance between the rotation center of the classifying rotor and the first bent portion of the blade B is represented by L2, R, L1, and L2 satisfy 0.35≤(L2-L1) / (R-L1)≤0.70.

[0055] According to the present disclosure, a toner classification apparatus and a toner production method that exhibit excellent productivity even in the production of small-diameter toner can be provided.

[0056] Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 Schematic diagram of the classifying rotor used in the embodiment;

[0058] Figure 2A and Figure 2B This is an illustration of the swirl flow inside the rotor;

[0059] Figure 3 is a schematic diagram of a toner classification apparatus used in Examples;

[0060] Figure 4 Schematic diagram of the dispersion rotor used in the examples;

[0061] Figure 5 is a schematic diagram of a guide device used in the embodiment;

[0062] Figure 6 is a schematic diagram of a gasket used in the examples;

[0063] Figure 7 Schematic diagram of the classifying rotor used in the embodiment;

[0064] Figure 8 Schematic diagram of the classifying rotor used in the embodiment;

[0065] Figure 9 Schematic diagram of the classifying rotor used in the embodiment;

[0066] Figure 10 Schematic diagram of the classifying rotor used in the embodiment;

[0067] Figure 11 Schematic diagram of the classifying rotor used in the embodiment;

[0068] Figure 12 Schematic diagram of the classifying rotor used in the embodiment;

[0069] Figure 13 is a schematic diagram of a classifying rotor used in a comparative example;

[0070] Figure 14is a schematic diagram of a classifying rotor used in a comparative example; and

[0071] Figure 15 Schematic diagram of a classifying rotor used in a comparative example. DETAILED DESCRIPTION

[0072] Unless otherwise specified, the expressions "from XX to YY" and "XX to YY" indicating a numerical range in the present disclosure refer to a numerical range including the lower limit and the upper limit as endpoints. In addition, in the present disclosure, "particles with too small a diameter" refer to particles having a particle diameter significantly smaller than the target particle diameter.

[0073] The reference numerals in the various drawings are as follows.

[0074] 31. Classifying rotor, 32. Dispersing rotor, 33. Dispersing hammer, 34. Inlet for particles to be classified, 35. Supply device for particles to be classified, 36. Guide device, 37. Classification material removal port, 38. Liner, 39. Exhaust port for undersized particles, 40. Undersized particle collection device (cyclone separator), 41. Blower, 42. Static pressure gauge, 51. Guide device support member

[0075] Figure 1 A schematic diagram showing a classifying rotor provided in a toner classifying apparatus.

[0076] The classifying rotor includes a plurality of blades extending from the rotation center direction of the classifying rotor toward the outer circumference direction of the classifying rotor.

[0077] the plurality of blades being arranged with a defined gap established between the blades;

[0078] The gap forms an opening facing the rotation center area of the classifying rotor;

[0079] The plurality of blades include a first blade group consisting of blades A and a second blade group consisting of blades B, wherein the length of the blades B is longer than the length of the blades A.

[0080] The lengths of the blades A are substantially the same as each other, and the blades A are arranged at intervals in such a manner as to follow substantially the same paths as each other during rotation of the classifying rotor,

[0081] The lengths of the blades B are substantially the same as each other, and the blades B are arranged at intervals in such a manner as to follow substantially the same paths as each other during rotation of the classifying rotor,

[0082] The number of the blades A arranged between two adjacent blades B is 1 to 3.

[0083] Herein, “the lengths of the blades are substantially the same as each other” is not limited to the case where the lengths of the blades are strictly the same as each other, but also includes the case where the lengths of the blades are the same as each other to an extent that does not impair the effects of the present disclosure.

[0084] The portion of the blade B from the end portion on the rotation center side to the first bent portion may be straight or curved, and is preferably straight, such as Figure 1 In addition, the portion of the blade B from the first bend to the end portion on the outer peripheral side may be straight or curved, and is preferably straight, as shown in FIG. Figure 1 shown.

[0085] In the case where the blade B has a second bent portion described later, the portion of the blade B from the first bent portion to the second bent portion may be straight or curved, and is preferably straight, such as Figure 7 In addition, the portion of the blade B from the second bend to the end portion on the outer peripheral side may be straight or curved, and is preferably straight, as shown in FIG. Figure 7 shown.

[0086] The portion of the blade A from the end on the rotation center side to the end on the outer periphery side may be straight or curved, and is preferably straight, such as Figure 1 shown.

[0087] In the case where the blade A has a bent portion described later, the portion of the blade A from the end portion on the rotation center side to the bent portion may be straight or curved, and is preferably straight, such as Figure 7 In addition, the portion of the blade A from the bent portion to the end portion on the outer peripheral side may be straight or curved, and is preferably straight, as shown in FIG. Figure 7 shown.

[0088] When the above-described classifying rotor is used, a toner classifying apparatus can be provided that reduces the load on the blower by suppressing the pressure loss caused by the classifying rotor, and exhibits excellent yield even when toner has a small particle size while sufficiently removing fine powder. The present inventors have hypothesized the factors for this in the following manner.

[0089] The centrifugal force acting on an object is given by [the weight of the object] × [the radius of gyration] × [the square of the angular velocity of the rotational motion]. In this article, the radius of gyration of the particles to be classified is considered to be the distance between the particles to be classified and the center of rotation of the classifying rotor. As described above, it can be considered that during the execution of the classification process, vortices are generated between the blades of the rapidly rotating classifying rotor. The presence of this vortex causes a local airflow that is strongly attracted inward, and it is speculated that this causes particles that should not have been removed to be sucked in and removed. When there is a vortex all the way to the inside of the classifying rotor, the particles to be classified are sucked in toward the inside of the classifying rotor, and the centrifugal force becomes smaller as the distance from the center of rotation becomes smaller. The particles to be classified cannot return to the outside of the classifying rotor, and as a result, particles with too small a diameter are eventually removed.

[0090] In a centrifugal air classifier such as the toner classifying device disclosed herein, air used to transport powder approaches from the outer periphery of the classifying rotor, passes between the rotor's blades, and then flows toward the rotor's rotational center and the undersized particle collection device connected to the rotor's rotational center. At this point, friction between the rotor blades and the air, as well as the generation of eddy currents between the blades, is believed to contribute to pressure loss.

[0091] It is believed that the air that has passed between the blades of the conventional classifier rotor becomes Figure 2A The swirling flow shown in FIG. 1 and flows to the device for collecting particles with too small a diameter when contacting the end of the blade on the rotation center side of the classifying rotor. Figure 1 As shown, the classifying rotor of the present disclosure has a first blade group consisting of blades A and a second blade group consisting of blades B, wherein the length of the blades B is longer than that of the blades A.

[0092] like Figure 2B As shown, the presence of blades B, which extend further toward the classifying rotor's center of rotation than blades A, restricts the swirl flow, reduces its radius of gyration, and reduces the relative velocity between the swirl flow and the ends of the classifying rotor's blades near the center of rotation. Furthermore, contact between the ends of blades A near the center of rotation and the swirl flow is prevented. In these circumstances, it is believed that pressure loss can be reduced by reducing friction between the classifying rotor's center of rotation and the air.

[0093] The number of blades A arranged between two adjacent blades B is 1 to 3. If the number of blades A arranged between two adjacent blades B is four or more, the blades B do not sufficiently restrict the swirl flow, making it impossible to suppress pressure loss. Furthermore, if the number of blades A is zero, the contact between the ends of the blades B on the rotation center side and the swirl flow increases, and the distance between the ends of adjacent blades B on the rotation center side decreases, making it difficult for air to pass between the blades, making it impossible to suppress pressure loss. The number of blades A arranged between two adjacent blades B does not have to be the same in all locations. The number can vary within the range of 1 to 3, such as being 2 in one location and 3 in another.

[0094] In addition, from the viewpoint of easily ensuring dynamic balance as a high-speed rotating member, the number of blades A arranged between the blades B is preferably 1 to 3, more preferably 1 or 2, and further preferably 1.

[0095] In a cross section obtained when the classifying rotor is cut in a direction perpendicular to the rotation axis of the classifying rotor, the classifying rotor is arranged so that a straight line connecting the rotation center of the classifying rotor and the end of the blade A on the rotation center side forms an angle θ1 with a portion of the blade A closer to the outer peripheral side than the end of the blade A on the rotation center side.

[0096] Herein, when blade A does not have a bent portion described later, "a portion of blade A closer to the outer periphery than the end portion on the rotation center side of blade A" refers to a portion where a straight line connecting the end portion on the rotation center side of blade A and the end portion on the outer periphery of blade A overlap with blade A. When blade A has a bent portion described later, "a portion of blade A closer to the outer periphery than the end portion on the rotation center side of blade A" refers to a portion where a straight line connecting the end portion on the rotation center side of blade A and the bent portion of blade A overlap with blade A.

[0097] The blade B, which has a length longer than that of the blade A, has a first bent portion.

[0098] Furthermore, the blades A and the blades B are arranged so that portions of the blades farther from the rotation center of the classifying rotor are located in an upstream direction in the rotation direction of the classifying rotor than portions of the blades closer to the rotation center of the classifying rotor.

[0099] Furthermore, the distance between the rotation center of the classifying rotor and the outer peripheral end of the blade A and the distance between the rotation center of the classifying rotor and the outer peripheral end of the blade B are substantially equal to each other.

[0100] Furthermore, the distance between the rotation center of the classifying rotor and the end of the blade A on the rotation center side and the distance between the rotation center of the classifying rotor and the first bent portion of the blade B are substantially equal to each other.

[0101] Furthermore, the distance between the rotation center of the classifying rotor and the end of the blade A on the rotation center side is greater than the distance between the rotation center of the classifying rotor and the end of the blade B on the rotation center side.

[0102] Furthermore, (ii) the classifying rotor is arranged so that the angle θ3 formed by the straight line connecting the rotation center of the classifying rotor and the first bent portion of the blade B and the portion of the blade B closer to the outer circumference than the first bent portion is substantially equal to the angle θ1.

[0103] Therefore, during rotation of the classifying rotor, the paths followed by the outer circumferences of the blades B constituting the second blade group located on the outer circumference side of the first bent portion and the paths followed by the blades A constituting the first blade group are substantially identical to each other.

[0104] Herein, "the distances are substantially equal to each other" is not limited to the case where the distances are strictly the same, but also includes the case where the distances are the same to the extent that the effects of the present disclosure are not impaired. Furthermore, "the paths followed by blades B and blade A during rotation of the stepping rotor are substantially the same" is not limited to the case where the paths are strictly the same, but also includes the case where the paths are the same to the extent that the effects of the present disclosure are not impaired.

[0105] In addition, when blade B does not have a second bent portion described later, "a portion of blade B closer to the outer periphery than the first bent portion of blade B" refers to a portion where a straight line connecting the first bent portion of blade B and the end portion on the outer periphery of blade B overlaps with blade B. When blade B has a second bent portion described later, "a portion of blade B closer to the outer periphery than the first bent portion of blade B" refers to a portion where a straight line connecting the first bent portion of blade B and the second bent portion of blade B overlaps with blade B.

[0106] (i) θ1 satisfies 40° to 65°. When θ1 is within the range of 40° to 65°, the vortex generated during classification can be positioned outside, and even if particles that should not be removed are attracted by the vortex, the particles can be returned to the outside of the classifying rotor because the centrifugal force is not reduced, so it is considered that the yield is improved.

[0107] When θ1 is less than 40°, the effect of positioning the vortex generated between the blades of the high-speed rotating classifying rotor to the outside is insufficient. When θ1 is greater than 65°, the distance between the ends of the blades of the classifying rotor near the rotation center becomes too short, making it difficult for particles with too small a diameter to be removed from the particles to be classified and for air conveying particles with too small a diameter to pass between the blades. This, in turn, contributes to reduced classification performance and increased pressure loss.

[0108] θ1 is preferably 45° to 65°, and more preferably 50° to 65°.

[0109] Furthermore, θ3 is preferably 45° to 65°, and more preferably 50° to 65°.

[0110] (iv) When the radius of the classifying rotor is represented by R and the distance between the rotation center of the classifying rotor and the end portion on the rotation center side of the blade B is represented by L1, R and L1 satisfy

[0111] 0.35≤L1 / R≤0.65.

[0112] When L1 / R is greater than 0.65, it is impossible to sufficiently reduce the gyration radius of the swirl flow that contacts the end of the blade on the rotation center side. When L1 / R is less than 0.35, the wind flowing in from the outside is excessively concentrated on the rotation center side of the stepping rotor, thereby eliminating the effect of suppressing pressure loss.

[0113] L1 / R is preferably from 0.40 to 0.55, and more preferably from 0.40 to 0.50.

[0114] (v) When the distance between the rotation center of the classifying rotor and the first bent portion of the blade B is represented by L2, R, L1 and L2 satisfy

[0115] 0.35≤(L2-L1) / (R-L1)≤0.70.

[0116] (L2-L1) / (R-L1) is a value representing the ratio of the length from the end on the rotation center side to the first bend portion to the length of blade B, and the larger the value, the longer the portion from the end on the rotation center side of blade B to the first bend portion.

[0117] When (L2-L1) / (R-L1) is less than 0.35, the first bend of blade B is positioned closer to the rotation center of the classifying rotor. As a result, the space between adjacent blades narrows, and the length from the end of blade B on the rotation center side to the first bend decreases (this length serves to reduce the gyration radius of the vortex flow that contacts the end of the blade on the rotation center side), making it impossible to reduce pressure loss. When (L2-L1) / (R-L1) is greater than 0.70, the length from the first bend of blade B to the end on the outer peripheral side decreases, thus failing to achieve the effect of localizing the vortex flow generated between the blades during classification to the outer side, and classification performance deteriorates.

[0118] (L2-L1) / (R-L1) is preferably from 0.40 to 0.65, and more preferably from 0.40 to 0.60.

[0119] (iii) An angle θ2 (°) formed by a straight line connecting the rotation center of the classifying rotor and the first bent portion of the blade B and a straight line connecting the end portion on the rotation center side of the blade B and the first bent portion of the blade B satisfies

[0120] 0°≤θ2≤θ3×1 / 2.

[0121] When the position of the first bend of blade B and L1 are fixed, and θ2 = 0° is satisfied, the length from the end of blade B on the rotation center side to the first bend is minimized, and the length from the end on the rotation center side to the first bend increases as θ2 increases. It is believed that when θ2 is greater than θ3 × 1 / 2, the contact area between the air and blade B increases, and the distance between the portion of the first bend of blade B closer to the rotation center and the end of the blade adjacent to blade B (i.e., blade A) on the rotation center side is shortened, thereby failing to achieve the effect of suppressing pressure loss.

[0122] The blade A preferably has a bent portion, and preferably satisfies at least one selected from the group consisting of (vi) to (viii) shown below.

[0123] (vi) Assuming that the distance from the rotation center of the classifying rotor to the end of the blade A on the rotation center side is L3, and the distance from the rotation center of the classifying rotor to the bent portion of the blade A is L4, it is preferable to satisfy 0.65 ≤ (L4 - L3) / (R - L3) ≤ 0.85. When (L4 - L3) / (R - L3) is 0.65 to 0.85, the classifying rotor's suppression of pressure loss, ability to remove particles with excessively small diameters, and output are further improved. (L4 - L3) / (R1 - L3) is more preferably 0.70 to 0.80.

[0124] (vii) The angle θ4 formed by a straight line connecting the end of blade A on the rotation center side and the bent portion of blade A and a straight line connecting the bent portion of blade A and the end of blade A on the outer periphery side is preferably 5° to 25°. When θ4 is 5° to 25°, the classifying rotor further improves pressure loss suppression, the ability to remove particles with excessively small diameters, and the yield. θ4 is more preferably 10° to 20°.

[0125] (viii) Preferably, blade B has a second bent portion on the outer peripheral side of the first bent portion, a distance L4 between the rotation center of the classifying rotor and the bent portion of blade A and a distance between the rotation center of the classifying rotor and the second bent portion of blade B are substantially equal to each other, and an angle θ5 formed by a straight line connecting the first bent portion of blade B and the second bent portion of blade B and a straight line connecting the second bent portion of blade B and the outer peripheral end of blade B is substantially equal to θ4. When the requirement in (viii) is satisfied, the eddy currents generated between the blades of the high-speed rotating classifying rotor are positioned further outward, thereby improving the yield rate, thereby satisfies the above requirement well.

[0126] R is not particularly limited and may be appropriately set according to the size of the classification apparatus and the amount of particles to be processed, and may be set to, for example, 60 mm to 200 mm, 60 mm to 120 mm, or 100 mm to 200 mm.

[0127] L1 is not particularly limited and may be appropriately set according to the size of the classification apparatus and the amount of particles to be processed, and may be set to, for example, 30 mm to 70 mm or 40 mm to 120 mm.

[0128] L2 is not particularly limited and may be appropriately set according to the size of the classification apparatus and the amount of particles to be processed, and may be set to, for example, 40 mm to 90 mm or 60 mm to 170 mm.

[0129] L3 is not particularly limited and may be appropriately set according to the size of the classification apparatus and the amount of particles to be processed, and may be set to, for example, 40 mm to 90 mm or 60 mm to 170 mm.

[0130] L4 is not particularly limited and may be appropriately set according to the size of the classification apparatus and the amount of particles to be processed, and may be set to, for example, 60 mm to 170 mm or 100 mm to 200 mm.

[0131] The means for producing the graded rotor are not particularly limited, and embodiments thereof include a method of producing individual components and assembling the individual components by welding, a method of using a metal 3D printer that melts and solidifies metal powder by laser irradiation to output a structure, die casting in which a metal mold is prepared and molten metal such as an aluminum alloy is injected into the metal mold with high pressure and formed, and evaporation pattern casting in which an evaporation pattern produced by a 3D printer is covered with a refractory material, the evaporation pattern is evaporated in the mold by applying heat from the outside, and metal is injected into the formed hollow portion.

[0132] Generally, production using welding or die casting has the advantage of high dimensional accuracy but the disadvantage of long production cycles. Using metal 3D printers or evaporation pattern casting has the advantages of being able to handle complex shapes and shortening delivery times, but has the disadvantage of limited production sizes. Taking into account the advantages and disadvantages of each production method, as well as the size, accuracy, and delivery time required for the target stepping rotor, the method used to produce the stepping rotor can be appropriately selected.

[0133] In order to remove particles with too small a diameter from the particles to be classified, the toner classification device should have the above-mentioned classification rotor, but is not particularly limited thereto, and the main unit of the toner classification device may have, for example, a supply device for supplying particles to be classified, a recovery device for the classified material after the classification process, and the like. As the particle size of the particles to be classified decreases, the number of particles per unit weight increases, and due to this, the number of particle-to-particle contact points increases, and then aggregates are more easily formed. From the viewpoint of being able to perform the classification step while decomposing these aggregates, as Figure 3 As shown, the toner classification device preferably has:

[0134] a cylindrical body shell;

[0135] The above-mentioned classification rotor 31;

[0136] a cylindrical guide 36 arranged to overlap at least a portion of the classifying rotor;

[0137] An introduction port 34 for particles to be classified and a supply device 35 for particles to be classified, the supply device 35 having an introduction port 34 for particles to be classified, the introduction port 34 and the supply device 35 being formed on a side surface of the body shell so as to introduce particles to be classified;

[0138] An undersized particle discharge port 39 and a classified particle removal port 37 are formed on a side surface of the body housing so as to discharge the classified particles from which the undersized particles have been removed from the body housing; and

[0139] The dispersion rotor 32 is a rotating body mounted to a central rotation axis within a body casing and has dispersion hammers (for example, rectangular blocks) 33 on a surface of the dispersion rotor 32 on the classifying rotor 31 side.

[0140] The body housing and guide 36 are not limited to cylindrical shapes and may take any shape.

[0141] Due to the presence of the guide device 36, an upward air flow toward the classifying rotor 31 is generated in the first space A, and a downward air flow toward the dispersion rotor 32 side is generated in the second space B. It can be said that this makes it possible to perform classification processing while the dispersion hammers 33 break up the aggregates of the particles to be classified. As long as the dispersion hammers 33 can break up the aggregates of the particles to be classified, they are not limited to rectangular blocks and can take any shape.

[0142] In addition, from the viewpoint of being able to improve fluidity by increasing the average circularity of the toner, it is more preferable that the spacer 38 is arranged at the circumference of the dispersion rotor 32 in a fixed manner while maintaining a distance from the circumference of the dispersion rotor 32. The spacer 38 is preferably provided with a groove in the surface facing the dispersion rotor 32.

[0143] It is believed that when the particles to be classified are impacted by, for example, the rotating dispersing hammers and the surface of the pad facing the dispersing hammers, the protrusions on the particles to be classified are flattened, resulting in an improvement in circularity. When the efficiency of removing particles with excessively small diameters during classification is low, the effect of improving the circularity of the particles may be reduced due to the persistence of the condition in which a large number of particles to be classified exist in the housing, compared to when the efficiency of removing particles with excessively small diameters is high.

[0144] The total number of blades of the classifying rotor (the sum of the number of blades A and the number of blades B) is not particularly limited and can be appropriately set according to the sizes of the classifying rotor and the classifying device and the amount of particles to be processed, and can be set, for example, to 20 to 80. The number of blades A of the classifying rotor is also not particularly limited and can be appropriately set according to the sizes of the classifying rotor and the classifying device and the amount of particles to be processed, and can be set, for example, to 10 to 40. The number of blades B of the classifying rotor is also not particularly limited and can be appropriately set according to the sizes of the classifying rotor and the classifying device and the amount of particles to be processed, and can be set, for example, to 10 to 40.

[0145] The height of the blades of the classifying rotor is not particularly limited and can be appropriately set according to the sizes of the classifying rotor and the classifying apparatus and the amount of particles to be processed, and can be set to, for example, 50 mm to 100 mm. Furthermore, the height of the opening of the classifying rotor is not particularly limited and can be appropriately set according to the sizes of the classifying rotor and the classifying apparatus and the amount of particles to be processed, and can be set to, for example, 50 mm to 100 mm.

[0146] The intervals at the ends on the outer peripheral side of the blades arranged in the classifying rotor are not particularly limited and may be appropriately set according to the sizes of the classifying rotor and the classifying apparatus and the amount of particles to be processed.

[0147] For example, the spacing between the outer peripheral ends of blades A and B arranged in the classifying rotor is preferably 5.0 mm to 25.0 mm. When the spacing is no greater than 25.0 mm, the vortex of the airflow generated between blades A and B arranged in the classifying rotor is less likely to become excessively large. Furthermore, when the spacing is no less than 5.0 mm, an increase in the time required for processing due to narrowing of the opening can be prevented. This spacing is more preferably 10.0 mm to 20.0 mm.

[0148] The dimensions of the body housing in the classification apparatus, such as height and inner diameter, are not particularly limited and can be appropriately set according to the size of the classification rotor and the amount of particles to be processed. The height of the body housing can be set, for example, to 150 mm to 500 mm. Furthermore, a body housing having an inner radius of, for example, 150 mm to 500 mm can be used as the body housing in the classification apparatus of the present disclosure.

[0149] The toner classification apparatus can be applied to powder particles produced by known production methods such as melt kneading / pulverization, suspension polymerization, emulsion aggregation, and dissolution suspension. However, considering that particles with excessively small diameters are easily generated when seeking smaller toner particle sizes, the toner classification apparatus is particularly advantageously used in melt kneading / pulverization. The procedure for producing toner by the melt kneading / pulverization method is described below, but is not limited to or is not limited to the following procedure.

[0150] Toner particle production method: First, in a raw material mixing step, at least a binder resin is weighed in a predetermined amount as a toner raw material and blended. For example, the following substances may be mixed as needed: a colorant, a release agent to suppress hot offset when the toner is heated and fixed, a dispersant to disperse the release agent, a charge control agent, etc. Examples of mixing equipment include a double cone mixer, a V-type mixer, a drum mixer, a super mixer, a Henschel mixer, and a Nauta mixer.

[0151] Then, in the melt kneading step, the toner raw materials blended in the raw material mixing step are melt kneaded, the resin is melted, and the colorant etc. are dispersed therein. For example, an intermittent kneading machine such as a pressure kneader, a Banbury mixer etc., or a continuous kneading machine can be used in this melt kneading step. In recent years, single screw and twin screw extruders have become mainstream because they provide advantages such as being able to produce continuously, and for example, the KTK type twin screw extruder from Kobe Steel, Ltd., the TEM type twin screw extruder from Toshiba Machine Co., Ltd., the twin screw extruder from KCK Co., Ltd., the co-kneader from Bus Co., Ltd., etc. are commonly used.

[0152] After melt-kneading, the melt-kneaded material provided by melt-kneading the toner raw material is spread using, for example, a two-roll mill, and cooled in a cooling step of cooling by, for example, water cooling.

[0153] Next, in the pulverization step, the cooled melt-kneaded material obtained in the cooling step is pulverized to the desired particle size. In the pulverization step, coarse pulverization is first performed using, for example, a crusher, hammer mill, or feather mill. Then, fine pulverization is performed using a mechanical pulverizer such as an Inomizer (manufactured by Hosokawa Micron Co., Ltd.), a Kryptron (manufactured by Kawasaki Heavy Industries, Ltd.), a Super Rotor (manufactured by Nissin Engineering Co., Ltd.), or a Turbo Mill (manufactured by Turbo Kogyo Co., Ltd.) to obtain a pulverized material. This stepwise pulverization is performed in the pulverization step until the toner particle size is obtained.

[0154] Using the pulverized material provided by the pulverization step as particles to be classified, toner particles are obtained by performing a classification process (classification step) on the particles to be classified using a toner classification apparatus.

[0155] The obtained toner particles can be used as a toner, for example, but, in order to provide the functions required for the toner, the obtained toner particles can be optionally made into a toner by adding inorganic fine particles (such as silica) to the toner particles, followed by, for example, performing a thermal spheroidization treatment.

[0156] In order to support improved toner transferability, the average circularity of the toner is preferably at least 0.955, more preferably at least 0.960. From the perspective of preventing cleaning defects, the average circularity is preferably not greater than 0.990.

[0157] Furthermore, from the perspective of improving the image quality of images formed using the toner, the weight average particle size of the toner is preferably small, and specifically preferably 3.50 μm to 6.00 μm, more preferably 3.50 μm to 5.00 μm. While a small weight average particle size is preferred for the toner, a value of at least 3.50 μm largely prevents this parameter from escaping the cleaning blade and causing image defects.

[0158] The number % of particles of 3.0 μm or less in the toner is preferably not more than 20.0 number %, more preferably not more than 15.0 number %, still more preferably not more than 10.0 number %.

[0159] Toner raw materials: The raw materials of the toner containing at least one binder resin are described below.

[0160] Binder Resin: Commonly used resins can be used as the binder resin, such as polyester resins, styrene-acrylic acid copolymers, polyolefin resins, vinyl resins, fluororesins, phenolic resins, silicone resins, and epoxy resins. Among these resins, amorphous polyester resins are preferred from the perspective of providing good low-temperature fixability. Combinations of low-molecular-weight polyester resins and high-molecular-weight polyester resins can be used to achieve both low-temperature fixability and hot offset resistance.

[0161] From the viewpoint of achieving additional improvement in anti-blocking properties during storage and low-temperature fixability, the crystalline polyester resin can also be used as a plasticizer.

[0162] Colorant: The toner raw material may include a colorant. The following are examples of colorants that may be included in the toner raw material. The colorants may be used alone or in combination of at least two.

[0163] Examples of the colorant include known organic pigments, oil-based dyes, carbon black, and magnetic substances.

[0164] Cyan colorants can be exemplified by copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, and basic dye lake compounds.

[0165] Magenta colorants can be exemplified by condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds.

[0166] The yellow colorant can be exemplified by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds.

[0167] The black colorant can be exemplified by carbon black and magnetic bodies, and a black colorant provided by color mixing using the above-mentioned yellow colorant, magenta colorant, and cyan colorant to obtain black.

[0168] Release agent: A release agent may be optionally used to suppress hot offset when the toner is heated and fixed. The release agent can typically be exemplified by low molecular weight polyolefins, silicone waxes, fatty acid amides, ester waxes, carnauba waxes, and hydrocarbon waxes.

[0169] Methods for measuring various properties of raw materials and toner are described below.

[0170] Method for measuring the weight average particle diameter (D4) of the toner: The weight average particle diameter (D4) of the toner is determined by performing measurement on the number of effective measurement channels in 25,000 channels and analyzing the measurement data using a "Coulter Counter Multisizer 3" (registered trademark, manufactured by Beckman Coulter, Inc.), using a precision particle size distribution measuring instrument that operates a pore resistance method and is equipped with a 100 μm aperture tube, and using the accompanying dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter, Inc.) to set measurement conditions and analyze measurement data.

[0171] The aqueous electrolyte solution used for measurement is prepared by dissolving special grade sodium chloride in deionized water to provide a concentration of about 1 mass %, and for example, "ISOTON II" (manufactured by Beckman Coulter Inc.) can be used.

[0172] Prior to measurement and analysis, dedicated software was constructed as follows.

[0173] In the "Modification of Standard Operating Method (MOM)" screen in the dedicated software, the total count in control mode was set to 50,000 particles; the number of measurements was set to 1; and the Kd value was set to the value obtained using "Standard Particles 10.0 μm" (Beckman Coulter). The threshold and noise level were automatically set by pressing the Threshold / Noise Level Measurement button. Furthermore, the current was set to 1600 μA; the gain was set to 2; the electrolyte solution was set to ISOTON II; and a check for post-measurement orifice tube flushing was entered.

[0174] In the "Pulse to Particle Size Setting Conversion" screen of the dedicated software, the bin interval was set to logarithmic particle size; the particle size element was set to 256 particle size elements; and the particle size range was set to 2 μm to 60 μm.

[0175] The specific measurement procedures are as follows.

[0176] (1) Approximately 200 mL of the above electrolyte aqueous solution was introduced into a 250 mL round-bottom glass beaker intended for use with the Multisizer 3, placed in a sample holder, and stirred counterclockwise at 24 rpm using a stirring rod. Contaminants and bubbles within the orifice tube were initially removed using the "orifice tube flush" function of the analysis software.

[0177] (2) About 30 mL of the electrolyte aqueous solution was introduced into a 100 mL flat-bottom glass beaker, and about 0.3 mL of a diluent as a dispersant was added thereto, the diluent being prepared by diluting "Contaminant N" (a 10% by mass aqueous solution of a neutral pH 7 detergent for cleaning precision measuring instruments, comprising a nonionic surfactant, an anionic surfactant, and an organic detergent, manufactured by Wako Pure Chemical Industries, Ltd.) with about 3 times the mass of deionized water.

[0178] (3) A prescribed amount of deionized water was introduced into a water tank of an "Ultrasonic Dispersion System Tetora 150" (manufactured by Nikkaki BIOS Co., Ltd.), which has an electrical output of 120 W and is equipped with two oscillators (oscillation frequency = 50 kHz) arranged with a phase shift of 180°, and approximately 2 mL of pollutant N was added to the water tank.

[0179] (4) Place the beaker described in (2) in a beaker holder with an opening on the ultrasonic disperser, and start the ultrasonic disperser. Adjust the vertical position of the beaker so that the surface resonance condition of the aqueous electrolyte solution in the beaker is at its maximum.

[0180] (5) While ultrasonic waves are being irradiated on the aqueous electrolyte solution in the beaker set up according to (4), approximately 10 mg of the toner is added to the aqueous electrolyte solution in small aliquots and dispersed. The ultrasonic dispersion treatment is continued for another 60 seconds. The water temperature in the water tank is appropriately controlled at 10°C to 40°C during the ultrasonic dispersion.

[0181] (6) Using a pipette, the dispersed electrolyte aqueous solution containing the toner prepared in (5) is dropped into the round-bottom beaker set in the sample stage as described in (1), and adjusted to provide a measurement concentration of approximately 5%. Measurement is then performed until the number of particles measured reaches 50,000.

[0182] (7) The measured data is analyzed using the dedicated software included with the instrument to calculate the weight average particle diameter (D4). 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).

[0183] Method for measuring the number % of colorants with a particle size of 3.0 μm or less: When the dedicated software is set to graph / number % in step (7) of the method for measuring the weight average particle size (D4) of the colorant, the cumulative value of the number % in the particle size region of 3.0 μm or less is the number % of 3.0 μm or less.

[0184] Method for measuring average circularity: The average circularity of the toner is measured using a flow-type particle image analyzer "FPIA-3000" (manufactured by Sysmex Corporation) under the measurement and analysis conditions used in the calibration process.

[0185] The specific measurement procedure is as follows. First, about 20mL of deionized water (for example, solid impurities have been removed therefrom in advance) is introduced into a glass container. About 0.2mL of a diluent as a dispersant is added thereto, the diluent being prepared by diluting a "pollutant N" (a 10% aqueous solution of a neutral pH 7 detergent for cleaning precision measuring instruments, comprising a nonionic surfactant, anionic surfactant and an organic detergent, manufactured by Wako Pure Chemical Industries, Ltd.) with about 3 times the mass of deionized water. About 0.02g of a measurement sample is added, and an ultrasonic disperser is used to perform a 2-minute dispersion process to provide a dispersion for measurement. Cooling is appropriately performed in the process so that the temperature of the dispersion is 10°C to 40°C. A desktop ultrasonic cleaner / disperser ("VS-150" (Velvo-Clear Corporation)) with an oscillation frequency of 50kHz and an electrical output of 150W is used as an ultrasonic disperser, a specified amount of deionized water is introduced into a water tank, and about 2mL of pollutant N is added to the water tank.

[0186] Measurements were performed using the aforementioned flow-type particle image analyzer equipped with a 10X objective lens, using a "PSE-900A" (Sysmex Corporation) particle sheath as the sheath solution. The dispersion prepared according to the above procedure was introduced into the flow-type particle image analyzer, and 3,000 toner particles were measured in the HPF measurement mode using the total count mode. The average circularity of the toner particles was determined using a binarization threshold of 85% during particle analysis and limiting the analyzed particle size to a circle-equivalent diameter of 1.985 μm to less than 39.69 μm.

[0187] For this measurement, automatic focus adjustment is performed before the start of measurement using reference latex particles ("RESEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5200A", manufactured by Duke Scientific, diluted with deionized water). Thereafter, focus adjustment is preferably performed every two hours after the start of measurement.

[0188] In the examples of the present application, the flow-type particle image analyzer used has been calibrated by Sysmex, and a calibration certificate has been issued by Sysmex. Upon receipt of the calibration certificate, measurement was performed using the measurement and analysis conditions except that the analyzed particle size was limited to a circle-equivalent diameter of 1.985 μm to less than 39.69 μm.

[0189] Example

[0190] The present disclosure is described in more detail below using Examples and Comparative Examples, but these Examples and Comparative Examples do not limit the embodiments of the present disclosure. Unless otherwise specifically stated, the parts given in the following Examples and Comparative Examples are by mass in all cases.

[0191] Production example of binder resin

[0192] Polyoxypropylene (2.2)-2,2-bis(4-hydroxyphenyl)propane: 72.0 parts (relative to the total molar number of the polyol: 100 mol%)

[0193] Terephthalic acid: 28.0 parts (96 mol% relative to the total moles of polycarboxylic acid)

[0194] 2-Ethylhexanoate (esterification catalyst): 0.5 parts

[0195] These materials were metered into a reactor equipped with a condenser, a stirrer, a nitrogen inlet line, and a thermocouple. The interior of the flask was then replaced with nitrogen, and the temperature was gradually increased while stirring, and the reaction was carried out at 220°C for 8 hours while stirring. The pressure in the reactor was then reduced to 8.3 kPa, maintained for 1 hour, and then cooled to 180°C and returned to atmospheric pressure.

[0196] Trimellitic anhydride: 1.3 parts (4 mol% relative to the total moles of polycarboxylic acid)

[0197] Tert-butylcatechol (polymerization inhibitor): 0.1 part

[0198] These materials were subsequently added, the pressure in the reactor 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 according to ASTM D 36-86 was 110° C.

[0199] Production Example of Pulverized Particles (Particles to be Classified) for Toner

[0200] Binder resin, 90 parts

[0201] Fischer-Tropsch wax (hydrocarbon wax, melting point = 90°C), 5 parts

[0202] CI Pigment Blue 15:3, 5 parts

[0203] A Henschel mixer (Model FM-75, manufactured by Mitsui Mining Co., Ltd.) was used for 20 s. -1These materials were mixed at a rotation rate of 0.5 and a rotation time of 5 minutes, and then kneaded using a twin-screw kneader (Model PCM-30, manufactured by Ikegai Co., Ltd.). 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 an HA-200E handheld thermometer manufactured by Anritsu Keiki Co., Ltd. The resulting kneaded product was cooled and coarsely pulverized using a hammer mill to a volume average particle diameter of not more than 100 μm to provide a coarsely pulverized material.

[0204] This coarsely pulverized material was pulverized using a mechanical pulverizer (Turbo Mill T250-CRS, rotor configuration: RS type, manufactured by Turbo Kogyo Co., Ltd.) at a rotor rotation rate of 11,000 rpm and a pulverization feed of 10 kg / h to obtain a finely pulverized material. This finely pulverized material was further pulverized using a rotor rotation rate of 12,000 rpm and a pulverization feed of 10 kg / h to obtain pulverized particles (particles to be classified) for use as a toner. The particles to be classified had a weight average particle size of 4.62 μm, a number percentage of particles 3.0 μm or less of 39.6%, and an average circularity of 0.951.

[0205] Toner grading equipment

[0206] Figure 3 The toner classification device shown is used for the structure of the toner classification device. The toner classification device is composed of the following:

[0207] a cylindrical body shell;

[0208] a disc-shaped dispersion rotor 32 which rotates at high speed and is a rotating body mounted to a central rotation axis within a body housing and has a plurality of dispersion hammers 33 on the surface of the rotating body on the classification rotor side;

[0209] a liner 38 disposed at the circumference of the dispersion rotor 32 while maintaining a distance therefrom;

[0210] A classifying rotor 31, which is a device for classifying particles to be classified;

[0211] The undersized particle discharge port 39 is used to discharge and remove particles not larger than a specified particle size selected by the classifying rotor 31;

[0212] a cooling air inlet (not shown), which is used to introduce cooling air from below the dispersion rotor;

[0213] a particle introduction port 34 for to-be-classified particles and a particle supply device 35 for to-be-classified particles, wherein the supply device 35 has a particle introduction port 34 for to-be-classified particles, and is used to introduce the particles to-be-classified into the interior of the body shell;

[0214] a classified particle removal port 37 for discharging the classified particles after the classification process; and

[0215] The cylindrical guide 36 is arranged so as to overlap at least a portion of the classifying rotor 31 .

[0216] The guide device 36 divides the space of the main body shell in the colorant classification device into space A and space B, in which an air flow is generated in the direction of introducing the particles to be processed into the classification rotor 31 and in space B, in which an air flow is generated in the direction of introducing the particles to be processed into between the dispersion rotor 32 and the pad 38.

[0217] The undersized particle discharge port 39 is connected to an undersized particle collecting device (cyclone separator) 40 for collecting discharged particles with an undersized diameter, and is connected to a blower 41 connected to the undersized particle collecting device 40. By using the blower 41, an air flow moving from the outside to the inside of the classifying rotor 31 can be generated. In addition, a static pressure gauge 42 is installed for measuring the pressure inside the body housing (static pressure on the classifying device inlet side) and the pressure in the undersized particle discharge port portion (static pressure on the classifying device outlet side).

[0218] When only the shape of the classifying rotor is different and the same classification conditions (such as the blower air volume and rotor RPM) are used, it can be considered that the pressure loss unique to the classifying rotor is low when the static pressure difference before and after the classifying device is small. When the pressure loss of the classifying device is small, when the air volume required for classification is output to a low level, this is preferable from the perspective of being able to suppress the load on the blower.

[0219] The height of the space in the main body shell is 300mm and the inner diameter is 300mm. The outer diameter of the dispersion rotor is 285mm. Figure 4 As shown, 8 dispersing hammers are installed on the dispersing rotor, and the length / width / height of each dispersing hammer are 30mm / 20mm / 20mm.

[0220] like Figure 5 As shown, the cylindrical guide is connected to the guide support member 51 and can be installed in any position by connecting the guide support member to the body shell using, for example, screws. The guide has a diameter of 250 mm and a height of 210 mm, and the distance between the upper end of the guide and the upper end of the shell is 40 mm.

[0221] liner

[0222] The pad 1 listed in Table 2 below has the following characteristics: Figure 6The pad has a plurality of protrusions as shown, with a concave portion formed between each protrusion. This concave-convex portion is triangular, with a repeat distance of 3 mm from protrusion to protrusion, a depth of 3.0 mm, and a pad height of 50 mm. Pad 2 listed in Table 2 below does not have the surface concave-convex portion of Pad 1, but has a smooth surface.

[0223] Classifying rotors 1 to 20 used in the examples (listed in Tables 1 and 2 below)

[0224] The classifying rotor 1 has Figure 7 The shape shown. One blade A included in the first blade group is arranged between two adjacent blades B included in the second blade group. The number of blades in the first blade group (blade A) is 16, and the number of blades in the arranged second blade group (blade B) is 16. R is 92 mm, L1 is 40 mm, L2 is 66 mm, L3 is 66 mm, L4 is 86 mm, θ1 is 60°, θ2 is 30°, θ3 is 60°, θ4 is 10°, θ5 is 10°, and the opening height of the stepping rotor is 70 mm.

[0225] Each of the classifying rotors 2 and 5 has Figure 7 Table 1 shows the differences between the classifying rotors 2 and 5 and the classifying rotor 1.

[0226] The classifying rotor 3 has Figure 8 One blade A included in the first blade group is arranged between two adjacent blades B included in the second blade group. The number of blades in the first blade group (blade A) is 18, and the number of blades in the arranged second blade group (blade B) is 18.

[0227] The classifying rotor 4 has Figure 9 One blade A included in the first blade group is arranged between two adjacent blades B included in the second blade group. The number of blades in the first blade group (blade A) is 14, and the number of blades in the arranged second blade group (blade B) is 14.

[0228] The classifying rotor 6 has Figure 1 The shape shown. One blade A included in the first blade group is arranged between two adjacent blades B included in the second blade group. The number of blades in the first blade group (blade A) is 16, and the number of blades in the arranged second blade group (blade B) is 16. R is 92 mm, L1 is 40 mm, L2 is 66 mm, L3 is 66 mm, θ1 is 60°, θ2 is 30°, θ3 is 60°, and the opening height of the stepping rotor is 70 mm.

[0229] Each of the classifying rotors 7 and 11 to 20 has Figure 1Regarding the classifying rotors 7 and 11 to 20, the points different from the classifying rotor 6 are shown in Table 1.

[0230] The classifying rotor 8 has Figure 10 The shape shown. One blade A included in the first blade group is arranged between two adjacent blades B included in the second blade group. The number of blades in the first blade group (blade A) is 15, and the number of blades in the arranged second blade group (blade B) is 15. R is 92 mm, L1 is 40 mm, L2 is 66 mm, L3 is 66 mm, θ1 is 60°, θ2 is 30°, θ3 is 60°, and the opening height of the stepping rotor is 70 mm.

[0231] The classifying rotor 9 has Figure 11 The shape shown. Two blades A included in the first blade group are arranged between two adjacent blades B included in the second blade group. The number of blades in the first blade group (blades A) is 22, and the number of blades in the arranged second blade group (blades B) is 11. R is 92 mm, L1 is 40 mm, L2 is 66 mm, L3 is 66 mm, θ1 is 60°, θ2 is 30°, θ3 is 60°, and the opening height of the stepping rotor is 70 mm.

[0232] The classifying rotor 10 has Figure 12 The shape shown. Three blades A included in the first blade group are arranged between two adjacent blades B included in the second blade group. The number of blades in the first blade group (blades A) is 24, and the number of blades in the arranged second blade group (blades B) is 8. R is 92 mm, L1 is 40 mm, L2 is 66 mm, L3 is 66 mm, θ1 is 60°, θ2 is 30°, θ3 is 60°, and the opening height of the stepping rotor is 70 mm.

[0233] Comparative rotors 1 to 10 for comparative examples (listed in Table 1 and Table 2 below)

[0234] Comparative rotor 1 has Figure 13 The shape shown is: R is 92 mm, L3 is 66 mm, θ1 is 60°, and the opening height of the grading rotor is 70 mm.

[0235] Comparative rotor 2 has Figure 14 The shape shown is: R is 92 mm, L1 is 40 mm, L2 is 66 mm, θ2 is 30°, θ3 is 60°, and the opening height of the grading rotor is 70 mm.

[0236] Each of the comparative rotors 3 to 9 has Figure 1 Table 1 shows the differences between the comparative rotors 3 to 9 and the classifying rotor 6.

[0237] The comparative rotor 10 has Figure 15 The shape shown. Four blades A included in the first blade group are arranged between two adjacent blades B included in the second blade group. The number of blades in the first blade group (blades A) is 24, and the number of blades in the arranged second blade group (blades B) is 6. R is 92 mm, L1 is 40 mm, L2 is 66 mm, L3 is 66 mm, θ1 is 60°, θ2 is 30°, θ3 is 60°, and the opening height of the stepping rotor is 70 mm.

[0238] [Table 1]

[0239]

[0240] Examples 1 to 22, Comparative Examples 1 to 10 (listed in Table 2 below)

[0241] After the classifying rotor 1 and the pad 1 are installed in the toner classifying device, the RPM of the classifying rotor is 9000 rpm, the rpm of the dispersion rotor is 5000 rpm, and the air volume of the blower is 10.0 m 3 Under the conditions of 1000 g / min, a classification cycle of 60 seconds (classification particle loading time of 10 seconds, classification time of 30 seconds, and classified particle collection time after classification of 20 seconds), the aforementioned pulverized particles were used as the particles to be classified, and the loading amount of the particles to be classified per cycle was 200 g, 60 cycles of classification were performed, and thus Toner 1 was obtained. In addition, as shown in Table 2, by changing the conditions, Toners 2 to 22 and Comparative Toners 1 to 10 were obtained.

[0242] In addition, the weight average particle size D4, the number % of particles not greater than 3.0 μm, and the average circularity of each toner were measured by the above-mentioned measuring device. In addition, the classification yield was determined from the loading amount of the particles to be classified (200 g×60 cycles) and the mass of the resulting toner.

[0243] Furthermore, under each classification condition, the static pressure on the outlet side of the classifying rotor before loading the particles to be classified (during idling operation) was subtracted from the static pressure on the inlet side of the classifying rotor, and the static pressure difference before and after the classifying rotor was calculated. At this time, the side closer to the blower, that is, the outlet side of the classifying rotor connected to the blower, has a more negative static pressure than the inlet side of the classifying rotor (the side connected to the loading port for classified particles), so the static pressure difference has a positive value.

[0244] The evaluation results are summarized in Table 2.

[0245] Evaluation: Output evaluation criteria

[0246] A: Output rate above 70.0%

[0247] B: Output rate 60.0% or more and less than 70.0%

[0248] C: Output rate 50.0% or more and less than 60.0%

[0249] D: Output rate 45.0% or more and less than 50.0%

[0250] E: Output rate is less than 45.0%

[0251] Evaluation: Evaluation criteria of number % of particles not larger than 3.0 μm

[0252] A: Less than 10.0%

[0253] B: 10.0% or more and less than 15.0%

[0254] C: 15.0% or more and less than 20.0%

[0255] D: 20.0% or more and less than 25.0%

[0256] E: 25.0% or more

[0257] Evaluation: Evaluation criteria for static pressure difference before and after the classifying rotor

[0258] A: Less than 7.20kPa

[0259] B: 7.20kPa or more and less than 7.60kPa

[0260] C: 7.60 kPa or higher and less than 8.00 kPa

[0261] D: 8.00kPa or more and less than 8.40kPa

[0262] E: 8.40kPa or more

[0263] Comprehensive evaluation

[0264] A: All projects are A-level (excellent).

[0265] B: At least one item (the lowest item) is rated B (good)

[0266] C: At least one item (the lowest item) is graded C

[0267] D: At least one item is D-level (not allowed in this disclosure)

[0268] E: At least one project is E-level (not allowed in this disclosure)

[0269] Reference evaluation: average roundness

[0270] A: Average roundness 0.960 or above

[0271] B: Average circularity 0.955 or more and less than 0.960

[0272] C: Average circularity less than 0.955

[0273] [Table 2]

[0274]

[0275] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A toner classification device comprising a classification rotor, wherein: The classifying rotor includes a plurality of blades extending from the rotation center direction of the classifying rotor toward the outer circumference direction of the classifying rotor. the plurality of blades being arranged with a defined gap established between the blades; The gap forms an opening facing the rotation center area of the classifying rotor; The plurality of blades include a first blade group consisting of blades A and a second blade group consisting of blades B, wherein the length of the blades B is longer than the length of the blades A. The lengths of the blades A are substantially the same as each other, and the blades A are arranged at intervals in such a manner as to follow substantially the same paths as each other during rotation of the classifying rotor, The lengths of the blades B are substantially the same as each other, and the blades B are arranged at intervals in such a manner as to follow substantially the same paths as each other during rotation of the classifying rotor, The number of blades A arranged between two adjacent blades B is 1 to 3, The blade B has a first bending portion, The blades A and the blades B are arranged so that portions of the blades farther from the rotation center of the classifying rotor are located upstream in the rotation direction of the classifying rotor compared to portions of the blades closer to the rotation center of the classifying rotor. The distance between the rotation center of the classifying rotor and the outer peripheral end of the blade A and the distance between the rotation center of the classifying rotor and the outer peripheral end of the blade B are substantially equal to each other. The distance between the rotation center of the classifying rotor and the end of the blade A on the rotation center side and the distance between the rotation center of the classifying rotor and the first bent portion of the blade B are substantially equal to each other. The distance between the rotation center of the classifying rotor and the end of the blade A on the rotation center side is greater than the distance between the rotation center of the classifying rotor and the end of the blade B on the rotation center side. In a cross section obtained when the classifying rotor is cut in a direction perpendicular to the rotation axis of the classifying rotor, i) an angle θ1 formed by a straight line connecting the rotation center of the classifying rotor and the end of the blade A on the rotation center side and a portion of the blade A closer to the outer circumference than the end of the blade A on the rotation center side is 40° to 65°, where the unit of the angle θ1 is degrees; ii) An angle θ3 formed by a straight line connecting the rotation center of the classifying rotor and the first bent portion of the blade B and a portion of the blade B closer to the outer circumference than the first bent portion of the blade B is substantially equal to angle θ1, and the unit of angle θ3 is degrees. iii) an angle θ2 formed by a straight line connecting the rotation center of the classifying rotor and the first bent portion of the blade B and a straight line connecting the end portion of the blade B on the rotation center side and the first bent portion of the blade B satisfies 0°≤θ2≤θ3×1 / 2, where the unit of the angle θ2 is degrees, iv) when the radius of the classifying rotor is represented by R and the distance between the rotation center of the classifying rotor and the end portion on the rotation center side of the blade B is represented by L1, R and L1 satisfy 0.35≤L1 / R≤0.65, and v) When the distance between the rotation center of the classifying rotor and the first bent portion of the blade B is represented by L2, R, L1, and L2 satisfy 0.35≤(L2-L1) / (R-L1)≤0.

70.

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

3. The toner classification apparatus according to claim 1 or 2, wherein The blade A has a bent portion, and vii) An angle θ4 formed by a straight line connecting the rotation center end of the blade A and the bent portion of the blade A and a straight line connecting the bent portion of the blade A and the outer peripheral end of the blade A is 5° to 25°.

4. The toner classification apparatus according to claim 1 or 2, wherein The blade A has a bent portion, and viii) the blade B has a second bent portion on the outer peripheral side of the first bent portion, The distance L4 between the rotation center of the grading rotor and the bent portion of the blade A and the distance between the rotation center of the grading rotor and the second bent portion of the blade B are substantially equal to each other, and The angle θ5 formed by the straight line connecting the first bending portion of the blade B and the second bending portion of the blade B and the straight line connecting the second bending portion of the blade B and the end portion on the outer peripheral side of the blade B is substantially equal to the angle θ4 formed by the straight line connecting the end portion on the rotation center side of the blade A and the bending portion of the blade A and the straight line connecting the bending portion of the blade A and the end portion on the outer peripheral side of the blade A.

5. The toner classification apparatus according to claim 1 or 2, wherein The interval between the outer peripheral ends of the blade A and the blade B is 5.0 mm to 25.0 mm.

6. The toner classification apparatus according to claim 1 or 2, further comprising: body shell; a guide device arranged in a state of overlapping with at least a portion of the classifying rotor; an introduction port for particles to be classified and a supply device for the particles to be classified, the supply device including the introduction port for the particles to be classified, the introduction port and the supply device being formed in a side surface of the body housing to introduce the particles to be classified; an undersized particle discharge port and a classified particle removal port formed in a side surface of the body case to discharge the classified particles from which the undersized particles have been removed to the outside of the body case; and A dispersion rotor is a rotating body mounted to a central rotation axis within the body casing, and includes dispersion hammers on a surface of the dispersion rotor on a classifying rotor side.

7. The toner classification apparatus according to claim 6, further comprising: A gasket is fixedly arranged at the circumference of the dispersing rotor while maintaining a distance from the circumference of the dispersing rotor.

8. The toner classification apparatus according to claim 7, wherein Grooves are arranged in the surface of the liner facing the dispersing rotor.

9. A method for producing a toner, comprising: A classification step in which a classification process is performed on particles to be classified by using a toner classification apparatus, wherein the toner classification apparatus is the toner classification apparatus according to claim 1 or 2.

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