Toner manufacturing method

Abstract

To provide a method for producing a toner in which a toner recovery rate is high and aggregation of the toner is suppressed.SOLUTION: A method for producing a toner includes a toner collecting step of collecting a toner using a toner collecting device that includes: a centrifugation cylinder; an airflow inlet; an airflow outlet through which an airflow is discharged; a toner collector for collecting toner; and a suction portion that sections the inside of the centrifugation cylinder through the toner collector and has a filtration filter through which the toner in the suctioned airflow is filtered out. The ratio of a suction quantity (m3 / min) of the airflow suctioned by the suction portion to an introduction quantity (m3 / min) at which the airflow containing the toner is introduced to the centrifugation cylinder is more than 0% and 30% or less, and the ratio of a filtration area (m2) of the filtration filter to the suction quantity (m3 / min) ratio of the airflow suctioned by the suction portion is 0.4 or more and 4.0 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing a toner. [Background technology]

[0002] For example, Patent Document 1 discloses "a cyclone comprising a cyclone cylinder having an opening at its lower end, a gas inlet section for introducing dust-containing gas into the cyclone cylinder to generate a swirling flow, an inner cylinder serving as an outlet for clean gas and having an outer diameter smaller than the inner diameter of the cyclone cylinder and arranged along the axis of the cyclone cylinder, and a dust collection chamber arranged to surround the opening at the lower end of the cyclone cylinder and having a dust outlet at its lower part, wherein a diffuser is provided at or upstream of the gas inlet section, and a gas passage is provided that connects a suction port provided near the inlet of the diffuser with a suction port provided in the dust collection chamber, and wherein a portion of the dust-containing gas from the dust collection chamber flows back to the gas inlet section via the gas passage." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-55102 Summary of the Invention [Problem to be solved by the invention]

[0004] The object of the present invention is to provide a method for producing toner that has a higher toner recovery rate and suppresses toner aggregation than a toner production method that includes a toner recovery step in which toner is recovered using a toner recovery device that includes: a centrifugal separator that introduces an airflow containing toner into which the toner is separated by a swirling flow generated by the introduced airflow; an airflow inlet that introduces the airflow containing toner into the centrifugal separator; an airflow outlet that is provided at the upper end of the centrifugal separator and discharges the airflow from which the toner has been separated in the centrifugal separator; and a toner recovery unit that is provided at the lower end of the centrifugal separator and recovers the toner separated in the centrifugal separator, the toner recovery unit being a suction unit that sucks the inside of the centrifugal separator through the toner recovery unit and does not include a suction unit having a filter that filters the toner in the sucked airflow. [Means for solving the problem]

[0005] Specific means for solving the above problems include the following aspects. <1> a centrifugal separator cylinder into which an airflow containing toner is introduced and which separates the toner by a swirling flow generated by the introduced airflow; an airflow inlet portion that introduces an airflow containing the toner into the centrifugal separator; an airflow discharge portion provided at an upper end of the centrifugal separator cylinder and configured to discharge an airflow from which the toner has been separated in the centrifugal separator cylinder; a toner recovery section provided at a lower end of the centrifugal separator cylinder to recover the toner separated by the centrifugal separator cylinder; a suction section that sucks the inside of the centrifugal separator cylinder through the toner recovery section, the suction section having a filter that filters the toner in the sucked airflow; a toner recovery step of recovering toner using a toner recovery device comprising: The amount of the airflow containing the toner introduced into the centrifugal separator cylinder is Qin(m 3 / min) to the suction volume QBD (m 3 / min) is greater than 0% and less than 30%, The amount of airflow sucked by the suction unit QBD (m 3 / min) ratio of the filtration area A (m 2 ) ratio is between 0.4 and 4.0, Toner manufacturing method. <2> The amount of airflow Qin(m 3 / min), and the inner diameter d (m) at the airflow introduction position of the centrifugal separator is 5≦Qin / d 2 Meet ≦500 <1> 10. The method for producing the toner according to claim 9. <3> The amount of airflow sucked by the suction unit QBD (m 3 / min), and the inner diameter d (m) at the airflow introduction position of the centrifugal separator is 0 <QBD / d 2 Meet ≦150 <2> 10. The method for producing the toner according to claim 9. <4> The filtration area A (m 2 ) and the inner diameter d (m) at the airflow introduction position of the centrifugal separator is 0.5≦A / d 2 Meets ≦100 <3> 10. The method for producing the toner according to claim 9. <5> The toner recovery device has a backwashing unit that backwashes the filter. <1> ~ <4> 10. The method for producing the toner according to claim 9, wherein the toner is a hydroxybenzoate. <6> The backwashing frequency of the backwashing unit for backwashing the filtration filter is 0.5 times / min or more. <5> 10. The method for producing the toner according to claim 9. <7> The pressure difference between the inside and outside of the filter is greater than 0 KPa and less than or equal to 0.5 KPa. <5> or <6> 10. The method for producing the toner according to claim 9. <8> When the inner diameter (m) of the centrifugal separator at the airflow introduction position is d, The distance between the center of the connecting portion of the centrifugal separator and the toner recovery unit and the center of the connecting portion of the toner recovery unit and the suction unit is 0.3d or more and 1.5d or less. <1> ~ <7> 10. The method for producing the toner according to claim 9, wherein the toner is a hydroxybenzoate. <9> When the inner diameter (m) of the centrifugal separator at the airflow introduction position is d, The diameter of the connecting portion between the toner recovery portion and the suction portion is 0.3d or more and 1.5d or less. <8> 10. The method for producing the toner according to claim 9. [Effects of the Invention]

[0006] <1> According to the invention, a method for producing toner is provided, which includes: a centrifugal separator which introduces an airflow containing toner into which the toner is centrifuged by a swirling flow generated by the introduced airflow; an airflow inlet which introduces the airflow containing toner into the centrifugal separator; an airflow outlet which is provided at the upper end of the centrifugal separator and discharges the airflow from which the toner has been separated in the centrifugal separator; and a toner recovery unit which is provided at the lower end of the centrifugal separator and recovers the toner separated in the centrifugal separator, and which has a higher toner recovery rate and suppresses toner aggregation than a toner production method which includes a toner recovery step in which toner is recovered using a toner recovery device which does not have a suction unit which sucks the inside of the centrifugal separator through the toner recovery unit and has a filter which filters the toner in the sucked airflow.

[0007] <2> According to the present invention, the amount of the airflow containing the toner introduced into the centrifugal separator cylinder is Qin(m 3 / min), and the inner diameter d (m) at the airflow introduction position of the centrifugal separator is 5≦Qin / d 2 The present invention provides a method for producing a toner that has a higher toner recovery rate and suppresses toner aggregation, as compared to a case where the condition ≦500 is not satisfied.

[0008] <3> According to the invention, the suction amount QBD(m 3 / min), and the inner diameter d (m) at the airflow introduction position of the centrifugal separator is 0 <QBD / d 2 This provides a method for producing a toner that has a higher toner recovery rate and suppresses toner aggregation, as compared to when the ratio does not satisfy ≦150.

[0009] <4> According to the invention, the filtration area (m 2 ) A, and the inner diameter d (m) at the airflow introduction position of the centrifugal separator tube is 0.5≦A / d 2As compared with the case where the condition ≦100 is not satisfied, a toner production method is provided in which the toner recovery rate is high and toner aggregation is suppressed.

[0010] <5> According to the present invention, a method for producing toner is provided that has a higher toner recovery rate and suppresses toner aggregation compared to when the toner recovery device does not have a backwashing section that backwashes the filtration filter.

[0011] <6> According to the present invention, a method for producing toner is provided in which the toner recovery rate is higher and toner aggregation is suppressed compared to when the frequency of backwashing the filtration filter by the backwashing section is less than 0.5 times / min.

[0012] <7> According to the invention, a method for producing toner is provided that has a higher toner recovery rate and suppresses toner aggregation, compared to when the pressure difference between the inside and outside of the filter exceeds 0.5 KPa.

[0013] <8> According to the invention, a method for producing toner is provided in which the toner recovery rate is higher and toner aggregation is suppressed compared to when the distance between the center of the connecting part of the centrifugal separator and the toner recovery part and the center of the connecting part of the toner recovery part and the suction part is less than 0.3d or more than 1.5d.

[0014] <9> According to the present invention, a method for producing toner is provided which has a higher toner recovery rate and suppresses toner aggregation, compared to when the diameter of the connecting part between the toner recovery part and the suction part is less than 0.3d or more than 1.5d. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 2 is a schematic diagram illustrating an example of a toner recovery device used in the toner manufacturing method according to the present embodiment. [Figure 2] 2 is a partially enlarged schematic diagram showing an example of a toner recovery device used in the toner manufacturing method according to the present embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] The following describes an embodiment of the present invention, which is an example of the present invention. These descriptions and examples are for illustrating the present invention, but are not intended to limit the present invention.

[0017] In this specification, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the present specification, the upper or lower limit of one numerical range may be replaced by the upper or lower limit of another numerical range. In addition, in the numerical ranges described in this disclosure, the upper or lower limit of the numerical range may be replaced by the values ​​shown in the examples.

[0018] In this specification, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved.

[0019] When embodiments are described in this specification with reference to the drawings, the configuration of the embodiment is not limited to the configuration shown in the drawings. Furthermore, the sizes of the components in each drawing are conceptual, and the relative size relationships between the components are not limited to these.

[0020] In this specification, each component may contain multiple corresponding substances. When referring to the amount of each component in a composition in this disclosure, if multiple substances corresponding to each component are present in the composition, the total amount of the multiple substances present in the composition is meant unless otherwise specified.

[0021] <Toner manufacturing method> The method for producing the toner (specifically, the toner for developing an electrostatic image) according to this embodiment includes a toner recovery step of recovering the toner using a toner recovery device. The toner recovery device a centrifugal separator cylinder into which an airflow containing toner is introduced and which separates the toner by a swirling flow generated by the introduced airflow; an airflow inlet portion that introduces an airflow containing the toner into the centrifugal separator; an airflow discharge portion provided at an upper end of the centrifugal separator cylinder and configured to discharge an airflow from which the toner has been separated in the centrifugal separator cylinder; a toner recovery section provided at a lower end of the centrifugal separator cylinder to recover the toner separated by the centrifugal separator cylinder; a suction section that sucks the inside of the centrifugal separator cylinder through the toner recovery section, the suction section having a filter that filters the toner in the sucked airflow; Equipped with. The amount of airflow containing the toner introduced into the centrifugal separator is (m 3 The suction volume (m / min) of the airflow sucked by the suction unit 3 / min) is greater than 0% and less than 30%. The amount of airflow sucked by the suction unit (m 3 / min) ratio to the filtration area (m 2 ) is between 0.4 and 4.0.

[0022] In the toner manufacturing method according to the present embodiment, a toner with a high toner recovery rate and suppressed toner aggregation is manufactured by the above-described method. The reasons for this are presumed to be as follows.

[0023] In the toner manufacturing process, the toner is transported by air between processes, and therefore, a toner recovery device that utilizes centrifugal separation is used for recovery. Toner recovery devices cannot completely separate toner from the air, and any toner that is not collected by the device is collected in a dust collection filter installed in the device's exhaust pipe. However, because the collection rate of dust collection filters is low, recycling them is costly and time-consuming. Therefore, improvements in the performance and efficiency of toner recovery devices themselves are desired.

[0024] In this regard, a mechanism may be considered in which the recovery performance of the toner recovery device is improved and the airflow discharged by the centrifugal separation is circulated again to perform centrifugal separation (for example, Patent Document 1). However, when the airflow discharged by the centrifugal separation is circulated, toner may fuse and adhere within the circulation path.

[0025] In contrast, in the toner manufacturing method according to the present embodiment, the suction unit sucks the inside of the centrifugal separator through the toner recovery unit at a specific suction volume, generating an airflow toward the toner recovery unit on the inner wall side of the centrifugal separator, thereby increasing the centrifugal separation capacity, reducing the amount of toner contained in the airflow discharged from the airflow discharge unit, and increasing the toner recovery rate. Furthermore, by providing a filter in the suction unit, the toner contained in the airflow sucked by the suction unit is filtered by the filter, and by recovering the filtered material, the toner recovery rate is further increased.

[0026] On the other hand, if the filtering area of ​​the filter is too small, friction and pressure may be applied to the toner when filtering the toner through the filter, which may cause the toner to aggregate. This is because the friction on the toner causes external additives to come off, or the pressure applied to the toner causes the external additives to become embedded, causing the toner to aggregate. On the other hand, if the filtering area of ​​the filter is too large, the amount of filtered material decreases, resulting in a low toner recovery rate. Therefore, the amount of airflow sucked in by the suction unit (m 3 / min) ratio of the filter's filtration area (m 2 By setting the ratio of (a) to (b) in the above range, the friction and pressure applied to the toner can be reduced while ensuring the toner recovery rate, thereby suppressing the generation of toner agglomerates. In addition, in the toner recovery device, the airflow sucked by the suction unit is not circulated, which prevents the formation of toner agglomerates.

[0027] From the above, it is presumed that the toner production method according to this embodiment can produce a toner with a high toner recovery rate and in which toner aggregation is suppressed.

[0028] In the toner manufacturing method according to the present embodiment, the toner recovery device may have a backwashing unit that backwashes the filtration filter. By backwashing the filter in the backwashing section, the toner filtered by the filter is released from the filter and collected in the toner collection section, which further improves the toner collection efficiency. It also reduces the frequency of filter replacement and enables continuous operation of the toner collection device.

[0029] The method for producing the toner according to this embodiment will be described in detail below.

[0030] First, an example of a toner recovery device used in the toner manufacturing method according to the present embodiment will be described.

[0031] The toner recovery machine 100 shown in FIG. 1 includes, for example, a centrifugal separator 10, an airflow introduction section 20, an airflow discharge section 30, a toner recovery section 40, a suction section 50, and a backwashing section 60. The backwashing unit 60 is an optional component and does not necessarily have to be provided in the toner recovery machine 100.

[0032] The centrifugal separator 10 is a separator into which an airflow containing toner is introduced and which separates the toner by centrifugal separation using a swirling flow generated by the introduced airflow. The centrifugal separator 10 has an inner cylinder 12, an outer cylinder 14 provided on the outside of the inner cylinder, and a conical cylinder 16 connected to the lower end of the outer cylinder 14, all of which are arranged coaxially.

[0033] The airflow introduction section 20 is an airflow introduction section that introduces an airflow containing toner into the centrifugal separator cylinder. The airflow introduction section 20 has an airflow introduction pipe 22 connected to the outer cylinder 14 of the centrifugal separator cylinder 10 .

[0034] The airflow discharge section 30 is provided at the upper end of the centrifugal separator cylinder and serves to discharge the airflow from which the toner has been separated in the centrifugal separator cylinder. The airflow discharge section 30 has an airflow discharge pipe 32 connected to the upper end of the inner cylinder of the centrifugal separator cylinder 10 .

[0035] The toner recovery section 40 is provided at the lower end of the centrifugal separation tube 10 and is a toner recovery section that recovers the toner separated by the centrifugal separation tube. The toner recovery section 40 has a recovery box 42 connected to the lower end of the conical cylinder 16 of the centrifugal separator cylinder 10 .

[0036] The suction unit 50 is a suction unit that sucks the inside of the centrifugal separator cylinder 10 through the toner recovery unit 40, and is a suction unit that has a filter 52 (for example, a bag filter) that filters toner in the sucked airflow. The suction section 50 has a filter tube 54 connected to the upper part of the collection box 42 at a position in the collection box 42 of the toner collection section 40 that is off the central axis of the conical tube 16 of the centrifugal separator tube 10, and a discharge pipe 56 that discharges the airflow that has passed through the filter tube 54. A cylindrical filter 52 is disposed inside the filter cylinder 54. The airflow sucked by the suction unit has toner filtered by the filter 52, and is then discharged from the discharge pipe 56. Although not shown, the discharge pipe 56 is connected to a suction pump (not shown), which sucks the inside of the centrifugal separator tube 10 through the toner recovery section 40 .

[0037] The backwashing unit 60 is a backwashing unit that backwashes the filtration filter 52 . The backwashing unit 60 has a gas injection unit 62 that injects gas, and a guide pipe 64 that guides the gas injected from the gas injection unit 62. One end of the guide tube 64, from which the guided gas is sprayed, is disposed inside the cylindrical filtration filter 52. The gas guided by the guide tube 64 is sprayed from the inside to the outside of the cylindrical filtration filter 52.

[0038] Next, each step of the toner manufacturing method according to this embodiment will be described. The toner manufacturing method according to this embodiment includes a toner recovery step of recovering toner using a toner recovery device. The toner recovered in the toner recovery process is, for example, toner in which an external additive has been added to toner particles, or toner that has not yet had an external additive added to toner particles and is transported by air current after being produced.

[0039] Specifically, the toner recovery process is carried out, for example, as follows. In the toner recovery device 100 shown in Fig. 1, an airflow containing toner (i.e., toner transported by the airflow) is introduced into the outer cylinder 14 of the centrifugal separator cylinder 10 from the airflow introduction section 20. At this time, the airflow containing toner is introduced so as to generate a swirling flow (i.e., a cyclone) inside the centrifugal separator cylinder 10. Inside the centrifugal separator cylinder 10, a swirling flow is generated from the outer cylinder 14 toward the conical cylinder 16, and the centrifugal force of the swirling flow separates the toner in the airflow. The separated toner falls by its own weight on the inner wall side of the centrifugal separator cylinder 10 into the collection box 42 of the toner collection section 40, where it is collected. The airflow from which the toner has been separated inside the centrifugal separator cylinder 10 passes through the inner cylinder 12 and is discharged from the airflow discharge pipe 32 of the airflow discharge section 30.

[0040] Meanwhile, while an airflow containing toner is being introduced from the airflow introduction pipe 22 of the airflow introduction section 20 to the outer cylinder 14 of the centrifugal separator cylinder 10, the suction section 50 sucks the inside of the centrifugal separator cylinder 10 through the toner recovery section 40. When the suction section 50 sucks the inside of the centrifugal separator cylinder 10, an air flow toward the toner recovery section 40 is generated on the inner wall side of the centrifugal separator cylinder 10. This increases the centrifugal separation capacity. The airflow sucked by the suction unit 50 is filtered by a cylindrical filter 52 provided inside a filter cylinder 54 . The airflow filtered by the filter 52 is discharged from the discharge pipe 56 .

[0041] In the backwashing unit 60, gas is injected from the gas injection unit 62 through the guide tube 64 from the inside to the outside of the cylindrical filter 52. This removes the filtered material (i.e., toner) from the filter 52. The removed filtered material (i.e., toner) then falls into the collection box 42 of the toner collection unit 40 and is collected.

[0042] As described above, in the toner recovery process, the toner transported by the air current is captured and recovered by the toner recovery device.

[0043] In the toner recovery device 100, the amount of airflow containing toner introduced into the centrifugal separator tube 10 is Qin (m 3 / min) of the airflow suctioned by the suction unit 50 QBD (m 3 / min) ratio (QBD / Qin) is greater than 0% and less than 30%. By setting the ratio (QBD / Qin) in the above range, the flow rate of the airflow generated on the inner wall side of the centrifugal separator cylinder 10 toward the toner recovery section 40 increases, improving the centrifugal separation performance. This increases the toner recovery rate. From the viewpoint of improving the toner recovery rate, the ratio (QBD / Qin) is preferably 1% or more and 20% or less, and more preferably 2% or more and 10% or less.

[0044] The amount of airflow Qin introduced into the centrifugal separator 10 is 3 m 3 / min or more 100m 3 / min is preferred, 10m 3 / min or more 50m 3 / min is more preferable. The suction volume QBD of the airflow sucked by the suction unit 50 is 1 m 3 / min or more 30m 3 / min is preferred, 3m 3 / min or more 15m 3 / min is more preferable. The amount of airflow discharged Qout from the airflow discharge section 30 is the amount of introduction Qin minus the amount of suction QBD.

[0045] Here, the amount introduced Qin(m3 / min) is the amount measured by a flow meter at the air flow introduction position of the centrifugal separator 10 (that is, the connection between the air flow introduction pipe 22 of the air flow introduction section 20 and the outer cylinder 14 of the centrifugal separator 10). Suction amount QBD(m 3 / min) is the amount measured at the discharge pipe 56 of the suction unit 50.

[0046] The amount of air drawn by the suction unit QBD (m 3 / min) ratio of the filtration area A (m 2 ) ratio (A / QBD) is between 0.4 and 4.0 When the ratio (A / QBD) is in the above range, the friction and pressure applied to the toner are reduced while ensuring the toner recovery rate, thereby suppressing the generation of toner agglomerates. From the viewpoint of improving the toner recovery rate and suppressing the generation of toner aggregates, the ratio (A / QBD) is preferably 0.5 or more and 3.5 or less, and more preferably 1 or more and 3 or less.

[0047] The amount of airflow Qin (m) containing toner introduced into the centrifugal separator tube 10 3 / min), and the inner diameter d (m) at the airflow introduction position of the centrifugal separator 10 is 5≦Qin / d 2 ≦500, and 50≦Qin / d 2 It is more preferable that the value be ≦300. 5≦Qin / d 2 If the ratio is ≦500, the friction and pressure on the toner can be reduced while strengthening the swirling flow generated inside the centrifugal separator 10. Therefore, the toner recovery rate is likely to be improved and toner agglomerates are less likely to be generated.

[0048] Here, the inner diameter at the air flow introduction position of the centrifugal separator 10 refers to the opening diameter of the connection between the air flow introduction pipe 22 of the air flow introduction section 20 and the outer cylinder 14 of the centrifugal separator 10, and is the average value of the maximum and minimum diameters.

[0049] The amount of airflow sucked by the suction unit 50 QBD (m 3 / min), and the inner diameter d (m) at the airflow introduction position of the centrifugal separator 10 is 0 <QBD / d 2 It is preferable that the value satisfies ≦150, and 10 <QBD / d 2 It is more preferable that ≦50 is satisfied. 0 <QBD / d 2 If the ratio is ≦150, the friction and pressure on the toner can be reduced while the suction force inside the centrifugal separator 10 can be strengthened. Therefore, the toner recovery rate is likely to be improved and toner agglomerates are less likely to occur.

[0050] Filtration area of ​​the filter 52 (m 2 ) A, and the inner diameter d (m) of the centrifugal separator 10 at the airflow introduction position is 0.5≦A / d 2 ≦100, and 10≦A / d 2 ≦50 is more preferred. 0.5≦A / d 2 If the ratio is ≦100, the friction and pressure on the toner can be reduced while the suction force inside the centrifugal separator tube 10 can be strengthened. Therefore, the toner recovery rate is likely to be improved and toner agglomerates are less likely to occur.

[0051] The frequency of backwashing the filtration filter by the backwashing unit 60 is preferably 0.5 times / min or more, and more preferably 0.8 times / min or more. When the cleaning frequency is within the above range, the amount of toner accumulated in the filter 52 increases, reducing the friction and pressure acting on the toner, and making it easier to suppress the generation of toner agglomerates. However, the upper limit of the cleaning frequency is preferably 1 time / min or less. If the backwashing frequency is too high, the effect of the suction part sucking the inside of the centrifugal separator through the toner recovery part will be weakened, and the recovery efficiency will decrease.

[0052] The pressure difference between the inside and outside of filtration filter 52 is preferably greater than 0 KPa and equal to or less than 0.5 KPa, and more preferably equal to or greater than 0.1 KPa and equal to or less than 0.4 KPa. When the pressure difference between the inside and outside of the filter 52 is within the above range, adhesion of the toner filtered by the filter 52 is suppressed, and the backwashing of the filter 52 can be performed while reducing the amount of gas injected by the backwashing unit 60. In addition, the friction and pressure acting on the toner filtered by the filter 52 are reduced, which makes it easier to suppress the generation of toner agglomerates.

[0053] The internal and external pressures of the filtration filter 52 are measured at positions before and after the filter.

[0054] When the inner diameter (m) of the centrifugal separator 10 at the airflow introduction position is d, the distance D (see Figure 2) between the center of the connection between the centrifugal separator 10 and the toner recovery section 40 and the center of the connection between the toner recovery section 40 and the suction section 50 is preferably 0.3d or more and 1.5d or less, and more preferably 0.5d or more and 1.2d or less. When the distance D is set within the above range, the swirling flow generated in the centrifugal separator 10 is not disrupted, and the suction section 50 easily generates an airflow toward the toner recovery section on the inner wall side of the centrifugal separator 10. This increases the centrifugal separation ability of the toner, and makes it easier to improve the toner recovery rate.

[0055] The center of the connection between the centrifugal separator 10 and the toner recovery unit 40 indicates the part located on the central axis of the lower end of the conical cylinder 16 of the centrifugal separator 10 that is connected to the toner recovery unit 40 . The center of the connection between the toner recovery unit 40 and the suction unit 50 indicates the part located on the central axis of the lower end of the filter cylinder 54 of the suction unit 50 that is connected to the toner recovery unit 40.

[0056] The diameter B of the connecting portion between the toner recovery portion 40 and the suction portion 50 is preferably 0.3d or more and 1.5d or less, and more preferably 0.5d or more and 1.2d or less. When the diameter B is within the above range, it is possible to increase the amount of toner suctioned by the suction unit 50 while suppressing the toner collected by the toner collection unit 40 from scattering dust. As a result, the toner collection rate is likely to improve.

[0057] The diameter B of the connecting portion of the toner recovery portion 40 and the suction portion 50 is the opening diameter of the lower end of the filter cylinder 54 of the suction portion 50 that connects to the toner recovery portion 40, and is the average value of the maximum diameter and the minimum diameter.

[0058] Next, the toner that is the target of the toner recovery process in the toner manufacturing method according to the present embodiment (hereinafter also referred to as the toner according to the present embodiment) will be described.

[0059] The toner according to this embodiment contains toner particles and, if necessary, an external additive.

[0060] (toner particles) The toner particles are composed of, for example, a binder resin, and, if necessary, a colorant, a release agent, and other additives.

[0061] -Binder resin- Examples of binder resins include homopolymers of monomers such as styrenes (e.g., styrene, parachlorostyrene, α-methylstyrene, etc.), (meth)acrylic acid esters (e.g., methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc.), ethylenically unsaturated nitriles (e.g., acrylonitrile, methacrylonitrile, etc.), vinyl ethers (e.g., vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), and olefins (e.g., ethylene, propylene, butadiene, etc.), and vinyl resins made of copolymers of two or more of these monomers. Examples of the binder resin include non-vinyl resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, and modified rosin, mixtures of these with the vinyl resins, and graft polymers obtained by polymerizing vinyl monomers in the presence of these. These binder resins may be used alone or in combination of two or more.

[0062] As the binder resin, a polyester resin is preferable. Examples of polyester resins include known polyester resins.

[0063] The content of the binder resin is, for example, preferably 40% by mass to 95% by mass, more preferably 50% by mass to 90% by mass, and even more preferably 60% by mass to 85% by mass, based on the total mass of the toner particles.

[0064] -Coloring agent- Examples of colorants include carbon black, chrome yellow, Hansa Yellow, benzidine yellow, threne yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, Balkan orange, watch young red, permanent red, brilliant carmine 3B, brilliant carmine 6B, DuPont oil red, pyrazolone red, lithol red, rhodamine B lake, lake red C, pigment red, rose bengal, aniline blue, ultramarine blue, and the like. Examples of the dye include various pigments such as phosphorus blue, chalco oil blue, methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, and malachite green oxalate, and various dyes such as acridine-based, xanthene-based, azo-based, benzoquinone-based, azine-based, anthraquinone-based, thioindigo-based, dioxazine-based, thiazine-based, azomethine-based, indigo-based, phthalocyanine-based, aniline black-based, polymethine-based, triphenylmethane-based, diphenylmethane-based, and thiazole-based dyes. The colorant may be used alone or in combination of two or more kinds.

[0065] The colorant may be surface-treated as needed, or may be used in combination with a dispersant. Furthermore, a plurality of colorants may be used in combination.

[0066] The content of the colorant is, for example, preferably 1% by mass or more and 30% by mass or less, and more preferably 3% by mass or more and 15% by mass or less, based on the total mass of the toner particles.

[0067] -Mold release agent- Examples of release agents include hydrocarbon waxes, natural waxes such as carnauba wax, rice wax, and candelilla wax, synthetic or mineral / petroleum waxes such as montan wax, and ester waxes such as fatty acid esters and montanic acid esters, but are not limited thereto.

[0068] The melting temperature of the release agent is preferably 50°C or higher and 110°C or lower, and more preferably 60°C or higher and 100°C or lower. The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC) by using the "melting peak temperature" as described in the method for determining the melting temperature in JIS K 7121-1987 "Method for measuring transition temperatures of plastics."

[0069] The content of the release agent is, for example, preferably 1% by mass or more and 20% by mass or less, and more preferably 5% by mass or more and 15% by mass or less, based on the total mass of the toner particles.

[0070] -Other additives- Examples of other additives include well-known additives such as magnetic materials, charge control agents, inorganic powders, etc. These additives are contained in the toner particles as internal additives.

[0071] -Characteristics of toner particles, etc.- The toner particles may be toner particles of a single layer structure, or may be toner particles of a so-called core-shell structure composed of a core part (core particle) and a coating layer (shell layer) that coats the core part. Here, the toner particles having a core-shell structure may be composed of, for example, a core containing a binder resin and, if necessary, other additives such as a colorant and a release agent, and a coating layer containing the binder resin.

[0072] The volume average particle size (D50v) of the toner particles is preferably 2 μm or more and 10 μm or less, and more preferably 4 μm or more and 8 μm or less.

[0073] The various average particle sizes and particle size distribution indices of the toner particles are measured using a Coulter Multisizer II (manufactured by Beckman Coulter), and the electrolyte is measured using an ISOTON-II (manufactured by Beckman Coulter). For the measurement, 0.5 mg to 50 mg of the sample to be measured is added to 2 ml of a 5% aqueous solution of a surfactant (preferably sodium alkylbenzene sulfonate) as a dispersant, and this is then added to 100 ml to 150 ml of the electrolyte. The electrolyte solution containing the suspended sample is dispersed for 1 minute using an ultrasonic disperser, and the particle size distribution of particles with a particle size range of 2 μm to 60 μm is measured using a Coulter Multisizer II with an aperture diameter of 100 μm. The number of particles sampled is 50,000. Based on the particle size distribution measured, cumulative distributions of volume and number are drawn for each divided particle size range (channel) from the smallest diameter side, and the particle size at 16% of the cumulative total is defined as the volume particle size D16v, the number particle size D16p, the particle size at 50% of the cumulative total as the volume average particle size D50v, the cumulative number average particle size D50p, and the particle size at 84% of the cumulative total as the volume particle size D84v and the number particle size D84p. Using these, the volumetric particle size distribution index (GSDv) is (D84v / D16v) 1 / 2 , the number particle size distribution index (GSDp) is (D84p / D16p) 1 / 2 It is calculated as:

[0074] The average circularity of the toner particles is preferably 0.94 or more and 1.00 or less, and more preferably 0.95 or more and 0.98 or less.

[0075] The average circularity of toner particles is calculated by (circular equivalent perimeter) / (perimeter) [(perimeter of a circle having the same projected area as the particle image) / (perimeter of the particle projected image)]. Specifically, this value is measured by the following method. First, the toner particles to be measured are sucked and collected, forming a flat flow, and a still image of the particles is captured by instantaneously activating a strobe light, and the particle image is analyzed using a flow-type particle image analyzer (FPIA-3000 manufactured by Sysmex Corporation).The number of samples to be sampled when calculating the average circularity is 3,500. When the toner contains external additives, the toner (developer) to be measured is dispersed in water containing a surfactant, and then ultrasonic treatment is performed to obtain toner particles from which the external additives have been removed.

[0076] (external additives) Examples of external additives include inorganic particles such as SiO2, TiO2, Al2O3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, KO, Na2O, ZrO2, CaO·SiO2, KO·(TiO2)n, Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, and MgSO4.

[0077] The surfaces of inorganic particles as external additives are preferably subjected to a hydrophobic treatment. The hydrophobic treatment is carried out, for example, by immersing the inorganic particles in a hydrophobic treatment agent. The hydrophobic treatment agent is not particularly limited, and examples thereof include silane coupling agents, silicone oils, titanate coupling agents, and aluminum coupling agents. These may be used alone or in combination of two or more. The amount of the hydrophobic treatment agent is usually, for example, 1 part by mass or more and 10 parts by mass or less per 100 parts by mass of the inorganic particles.

[0078] Examples of external additives include resin particles (resin particles such as polystyrene, polymethyl methacrylate (PMMA), and melamine resin), cleaning agents (for example, metal salts of higher fatty acids such as zinc stearate, and particles of fluorine-based polymers).

[0079] The amount of the external additive added is, for example, preferably 0.01% by mass or more and 5% by mass or less, and more preferably 0.01% by mass or more and 2.0% by mass or less, based on the toner particles.

[0080] (Toner manufacturing method) Next, a method for producing the toner according to this embodiment will be described. The toner according to this exemplary embodiment is obtained by producing toner particles and then externally adding an external additive to the toner particles.

[0081] The toner particles may be produced by any of a dry production method (for example, a kneading and pulverization method) and a wet production method (for example, an aggregation and coalescence method, a suspension polymerization method, a dissolution and suspension method). The method for producing the toner particles is not particularly limited, and any well-known production method may be used. Among these, it is preferable to obtain toner particles by the aggregation and coalescence method.

[0082] Specifically, for example, when toner particles are produced by the aggregation and coalescence method, Toner particles are manufactured through the following steps: a step of preparing a resin particle dispersion in which resin particles that will become a binder resin are dispersed (resin particle dispersion preparation step); a step of aggregating the resin particles (and other particles, if necessary) in the resin particle dispersion (in a dispersion after mixing other particle dispersions, if necessary) to form aggregated particles (aggregated particle formation step); and a step of heating the aggregated particle dispersion in which the aggregated particles are dispersed to fuse and coalesce the aggregated particles to form toner particles (fusion and coalescence step).

[0083] Each step will be described in detail below. In the following description, a method for obtaining toner particles containing a colorant and a release agent will be described, but the colorant and the release agent are used as needed. Of course, additives other than the colorant and the release agent may also be used.

[0084] -Resin particle dispersion preparation process- First, a resin particle dispersion in which resin particles serving as a binder resin are dispersed, as well as a colorant particle dispersion in which colorant particles are dispersed and a release agent particle dispersion in which release agent particles are dispersed are prepared.

[0085] Here, the resin particle dispersion liquid is prepared, for example, by dispersing resin particles in a dispersion medium using a surfactant.

[0086] Examples of the dispersion medium used in the resin particle dispersion include aqueous media. Examples of aqueous media include water such as distilled water and ion-exchanged water, alcohols, etc. These may be used alone or in combination of two or more.

[0087] Examples of surfactants include anionic surfactants such as sulfate ester salts, sulfonate salts, phosphate esters, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; and nonionic surfactants such as polyethylene glycols, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, anionic surfactants and cationic surfactants are particularly preferred. Nonionic surfactants may be used in combination with anionic surfactants or cationic surfactants. The surfactants may be used alone or in combination of two or more.

[0088] In the resin particle dispersion, resin particles can be dispersed in a dispersion medium by a general dispersion method such as a rotary shear homogenizer, a ball mill having a medium, a sand mill, a dyno mill, etc. Depending on the type of resin particles, the resin particles may be dispersed in the resin particle dispersion by, for example, a phase inversion emulsification method. The phase inversion emulsification method involves dissolving the resin to be dispersed in a hydrophobic organic solvent in which the resin is soluble, adding a base to the organic continuous phase (O phase) to neutralize it, and then adding an aqueous medium (W phase), thereby converting the resin from W / O to O / W (so-called phase inversion) and forming a discontinuous phase, and dispersing the resin in particulate form in the aqueous medium.

[0089] The volume average particle size of the resin particles dispersed in the resin particle dispersion is, for example, preferably from 0.01 μm to 1 μm, more preferably from 0.08 μm to 0.8 μm, and even more preferably from 0.1 μm to 0.6 μm. The volume average particle size of the resin particles is measured using a particle size distribution obtained by measurement with a laser diffraction particle size distribution analyzer (e.g., LA-700 manufactured by Horiba, Ltd.), and the cumulative distribution for the volume of the divided particle size range (channel) is subtracted from the small particle size side, and the particle size at which the cumulative 50% of all particles is measured is defined as the volume average particle size D50v. The volume average particle sizes of particles in other dispersions are also measured in the same way.

[0090] The content of resin particles contained in the resin particle dispersion is, for example, preferably from 5% by mass to 50% by mass, and more preferably from 10% by mass to 40% by mass.

[0091] Note that, for example, a colorant particle dispersion and a release agent particle dispersion are also prepared in the same manner as the resin particle dispersion. That is, the volume average particle size, dispersion medium, dispersion method, and particle content of the particles in the resin particle dispersion are the same for the colorant particles dispersed in the colorant particle dispersion and the release agent particles dispersed in the release agent particle dispersion.

[0092] -Agglomerated particle formation process- Next, the colorant particle dispersion and the release agent particle dispersion are mixed together with the resin particle dispersion. Then, in the mixed dispersion, the resin particles, colorant particles, and release agent particles are hetero-aggregated to form aggregated particles containing the resin particles, colorant particles, and release agent particles and having a diameter close to that of the target toner particles.

[0093] Specifically, for example, an aggregating agent is added to the mixed dispersion, and the pH of the mixed dispersion is adjusted to be acidic (for example, a pH of 2 or more and 5 or less), and a dispersion stabilizer is added as necessary. After that, the mixed dispersion is heated to the glass transition temperature of the resin particles (specifically, for example, a temperature of the glass transition temperature of the resin particles -30°C or more and the glass transition temperature -10°C or less), and the particles dispersed in the mixed dispersion are aggregated to form aggregated particles. In the aggregate particle formation step, for example, the above-mentioned aggregating agent may be added to the mixed dispersion at room temperature (e.g., 25°C) while stirring with a rotary shear homogenizer, the pH of the mixed dispersion may be adjusted to an acidic value (e.g., pH 2 or more and 5 or less), and a dispersion stabilizer may be added as necessary, followed by the heating.

[0094] Examples of the flocculant include a surfactant having a polarity opposite to that of the surfactant used as the dispersant added to the mixed dispersion, an inorganic metal salt, and a divalent or higher metal complex. In particular, when a metal complex is used as the flocculant, the amount of surfactant used can be reduced and the charging characteristics can be improved. If necessary, an additive that forms a complex or a similar bond with the metal ions of the flocculant may be used, and a chelating agent is preferably used as this additive.

[0095] Examples of inorganic metal salts include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, as well as inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. The chelating agent may be a water-soluble chelating agent, such as hydroxycarboxylic acid (e.g., tartaric acid, citric acid, gluconic acid), iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA), etc. The amount of the chelating agent added is, for example, preferably 0.01 parts by mass or more and 5.0 parts by mass or less, and more preferably 0.1 parts by mass or more and less than 3.0 parts by mass, per 100 parts by mass of the resin particles.

[0096] -Fusion / unification process- Next, the aggregated particle dispersion liquid in which the aggregated particles are dispersed is heated, for example, to a temperature equal to or higher than the glass transition temperature of the resin particles (for example, a temperature 10 to 30°C higher than the glass transition temperature of the resin particles), to fuse and coalesce the aggregated particles and form toner particles.

[0097] Through the above steps, toner particles are obtained. After obtaining an aggregated particle dispersion in which aggregated particles are dispersed, the toner particles may be produced through the following steps: a step of further mixing the aggregated particle dispersion with a resin particle dispersion in which resin particles are dispersed, and aggregating the aggregated particles so that further resin particles adhere to the surfaces of the aggregated particles to form second aggregated particles; and a step of heating the second aggregated particle dispersion in which the second aggregated particles are dispersed to fuse and coalesce the second aggregated particles to form toner particles having a core / shell structure.

[0098] After the fusion and coalescence process, the toner particles formed in the solution are subjected to a known washing process, solid-liquid separation process, and drying process to obtain dry toner particles. In the washing step, it is preferable to carry out sufficient replacement washing with ion-exchanged water from the viewpoint of electrostatic chargeability. Furthermore, the solid-liquid separation step is not particularly limited, but from the viewpoint of productivity, it is preferable to carry out suction filtration, pressure filtration, etc. Furthermore, in the drying step, there is no particular limitation on the method, but from the viewpoint of productivity, it is preferable to carry out freeze drying, flash drying, fluidized drying, vibration-type fluidized drying, etc.

[0099] The toner according to this embodiment is produced by, for example, adding an external additive to the obtained dry toner particles and mixing them. The mixing can be carried out using, for example, a V blender, a Henschel mixer, a Loedige mixer, or the like. Furthermore, if necessary, coarse particles may be removed from the toner using a vibrating sieve, an air sieve, or the like. [Example]

[0100] Examples of the present invention will be described below, but the present invention is not limited to the following examples. In the following description, unless otherwise specified, all "parts" and "%" are based on mass.

[0101] <Examples 1 to 17 and Comparative Examples 1 to 4> [Preparation of amorphous polyester resin dispersion (1)] Terephthalic acid: 70 parts Fumaric acid: 30 parts Ethylene glycol: 44 parts 1,5-pentanediol: 47 parts The above materials were placed in a 5-liter flask equipped with a stirrer, nitrogen inlet tube, temperature sensor, and distillation column. The temperature was raised to 220°C over 1 hour under a nitrogen gas stream, and 1 part of dibutyltin oxide was added for every 100 parts of the above materials. The temperature was raised to 240°C over 0.5 hours while distilling off the resulting water. The dehydration condensation reaction was continued at that temperature for 1 hour, and then the reaction mixture was cooled. In this way, a polyester resin with a weight-average molecular weight of 95,000 and a glass transition temperature of 62°C was synthesized. 40 parts of ethyl acetate and 25 parts of 2-butanol were added to a vessel equipped with a temperature control device and nitrogen substitution device to form a mixed solvent. 100 parts of polyester resin were then gradually added and dissolved. A 10% by weight aqueous ammonia solution (equivalent to three times the molar amount of the acid value of the resin) was then added and stirred for 30 minutes. Next, the atmosphere inside the container was replaced with dry nitrogen, the temperature was maintained at 40°C, and 400 parts of ion-exchanged water was added dropwise at a rate of 2 parts / min while stirring the mixture, thereby emulsifying it. After the addition was completed, the emulsion was returned to 25°C, and a resin particle dispersion in which resin particles having a volume average particle size of 200 nm were dispersed was obtained. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20 mass% to obtain amorphous polyester resin dispersion (A1).

[0102] [Preparation of Crystalline Polyester Resin Dispersion (1)] Dimethyl sebacate: 97 parts Sodium dimethyl isophthalate-5-sulfonate: 3 parts Ethylene glycol: 100 parts Dibutyltin oxide (catalyst): 0.3 parts by mass The above components were placed in a heated and dried three-neck flask, and the air inside the vessel was evacuated to an inert atmosphere with nitrogen gas by reducing the pressure. The mixture was then mechanically stirred and refluxed at 180°C for 5 hours. The temperature was then gradually increased to 230°C under reduced pressure and stirred for 2 hours. When the mixture reached a viscous state, it was air-cooled to terminate the reaction, yielding crystalline polyester resin B1. Molecular weight measurement (polystyrene equivalent) revealed that the weight-average molecular weight (Mw) of the resulting "crystalline polyester resin B1" was 9700 and the melting temperature was 84°C. 90 parts by mass of the resulting crystalline polyester resin B1, 1.8 parts by mass of the ionic surfactant Neogen RK (Dai-ichi Kogyo Seiyaku), and 210 parts by mass of ion-exchanged water were heated to 100°C and dispersed using an IKA Ultra-Turrax T50. The mixture was then dispersed for 1 hour using a pressure-discharge Gaulin homogenizer to obtain crystalline polyester resin dispersion (1) with a volume average particle size of 200 nm and a solids content of 20 parts by mass.

[0103] [Preparation of Colored Particle Dispersion (1)] Carbon black (Cabot, Regal 1330): 50 parts Ionic surfactant Neogen RK (manufactured by Daiichi Kogyo Seiyaku): 10 parts Ion-exchanged water: 192.9 parts The above components were mixed and treated for 10 minutes at 240 MPa using an Ultimizer (manufactured by Sugino Machine Co., Ltd.) to prepare a black colored particle dispersion (solid content concentration: 20% by mass).

[0104] [Preparation of Release Agent Particle Dispersion (1)] Paraffin wax (HNP-9 manufactured by Nippon Seiro Co., Ltd.): 100 parts Anionic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 1 part Ion-exchanged water: 350 parts The above materials were mixed and heated to 100°C, dispersed using a homogenizer (Ultra Turrax T50 manufactured by IKA), and then dispersed using a Manton-Gaulin high-pressure homogenizer (manufactured by Gaulin) to obtain a release agent particle dispersion (solid content 20% by mass) in which release agent particles with a volume average particle size of 200 nm were dispersed. [Preparation of toner and developer] Ion-exchanged water: 200 parts Amorphous polyester resin dispersion (1): 150 parts Crystalline polyester resin dispersion (1): 10 parts Black colored particle dispersion: 15 parts Release agent particle dispersion: 10 parts Anionic surfactant (TaycaPower): 2.8 parts The above materials were placed in a round stainless steel flask, and 0.1 N nitric acid was added to adjust the pH to 3.5. An aluminum sulfate aqueous solution prepared by dissolving 2.0 parts aluminum sulfate in 30 parts ion-exchange water was then added. The mixture was dispersed at 30°C using a homogenizer (IKA Ultra-Turrax T50) and then heated to 45°C in a heating oil bath until the volume average particle size reached 4.8 μm. Subsequently, 60 parts of amorphous polyester resin particle dispersion (A1) were added and the mixture was maintained for 30 minutes. When the volume average particle size reached 5.2 μm, another 60 parts of amorphous polyester resin particle dispersion (1) were added and the mixture was maintained for 30 minutes. Subsequently, 20 parts of a 10% by weight NTA (nitrilotriacetic acid) metal salt aqueous solution (Chilest 70, manufactured by Chelest Co., Ltd.) was added, and the pH was adjusted to 9.0 using 1 N sodium hydroxide aqueous solution. Subsequently, 1.0 part of an anionic surfactant (TaycaPower) was added, and the mixture was heated to 85°C with continued stirring and maintained for 5 hours. The mixture was then cooled to 20°C at a rate of 20°C / min. Within 60 minutes after cooling, the pH was adjusted to 9.5 using a 1N aqueous solution of sodium hydroxide. After the pH adjustment, the mixture was filtered, thoroughly washed with ion-exchanged water, and dried to obtain toner particles with a volume average particle size of 5.9 μm and an average circularity of 0.97.

[0105] 100 parts of toner particles and 1.5 parts of hydrophobic silica (RY50, manufactured by Nippon Aerosil Co., Ltd.) were mixed and mixed for 30 seconds at a rotation speed of 10,000 rpm using a sample mill. The mixture was then sieved using a pneumatic sieving machine, Hivolta 300 (manufactured by Shin-Tokyo Kikai Co., Ltd., feed rate 600 kg / h, mesh size 38 μm) to obtain a toner.

[0106] Next, the obtained toner was transported by air current and collected by the toner collection device shown in FIGS. The settings of the toner recovery device were as shown in Table 1. In Comparative Example 1, the toner was collected by a toner collection device that was not provided with a suction section or a cleaning section.

[0107] The details of Table 1 are as follows: Introduced amount Qin: The amount of airflow containing toner introduced into the centrifugal separator Qin (m 3 / min) Suction volume QBD: The volume of air drawn by the suction unit QBD (m 3 / min) Filtration area A: The filtration area A of the filter (m 2 ) Airflow inlet diameter d: Inner diameter d (m) of the centrifuge tube at the airflow inlet position Cleaning frequency: The frequency of backwashing the filtration filter by the backwashing unit (times / min) F internal and external pressure difference: pressure difference between the inside and outside of the filtration filter Distance between the centrifugal separator and the suction unit: the distance between the center of the connection between the centrifugal separator and the toner recovery unit and the center of the connection between the toner recovery unit and the suction unit Suction port diameter B: The port diameter of the connecting part between the toner collection port and the suction port

[0108] <Evaluation> [Recovery efficiency] In each example, the toner recovery rate by the toner recovery device was evaluated according to the following criteria, with C being the acceptable range. -Evaluation criteria- A: Recovery rate of 99.5% or more B: Recovery rate 97% or more but less than 99.5% C: Recovery rate 95% or more but less than 97% D: Recovery rate less than 95%

[0109] [Cohesion (color point evaluation)] In each example, the cohesion of the toner recovered by the toner recovery device can cause color spots, so the occurrence of cohesion was determined by evaluating color spots. A developer for "Apeos PortIVC5575 (manufactured by Fujifilm Business Innovation Co., Ltd.)" containing the toner of each example was prepared. This developer was placed in a developing device of a modified image forming apparatus "Apeos PortIVC5575 (manufactured by Fujifilm Business Innovation Co., Ltd.)." Using this modified image forming device, after leaving it in a high temperature and humidity environment (28°C, 85% RH) for one day, images with an image density of 1% were continuously printed on 1000 sheets of A4 paper. 100 sheets out of 900 to 1000 were visually observed for the occurrence of color spots and evaluated according to the following criteria. A grade of C or lower was considered acceptable. -Evaluation criteria- A: No color dots B: The number of sheets with one or more color spots is between one and three C: The number of sheets with one or more color spots is between 3 and 5 D: Five or more sheets have one or more color spots.

[0110] [Table 1]

[0111] From the above results, it can be seen that in this embodiment, the toner recovery rate is higher than in the comparative example, and the toner aggregation can be suppressed. [Explanation of symbols]

[0112] 10 Centrifuge tube 12 Inner cylinder 14 outer cylinder 16 Conical Cylinder 20 Air flow inlet 22 Introductory tube 30 Airflow exhaust section 32 Airflow exhaust pipe 40 Toner collection section 42 Collection Box 50 Suction part 52 Filtration filter 54 Filter tube 56 Discharge pipe 60 Backwashing section 62 Gas injection section 64 Guide tube 100 Toner recovery device

Claims

1. a centrifugal separator cylinder into which an airflow containing toner is introduced and which separates the toner by a swirling flow generated by the introduced airflow; an airflow inlet portion that introduces an airflow containing the toner into the centrifugal separator; an airflow discharge portion provided at an upper end of the centrifugal separator cylinder and configured to discharge an airflow from which the toner has been separated in the centrifugal separator cylinder; a toner recovery section provided at a lower end of the centrifugal separator cylinder to recover the toner separated by the centrifugal separator cylinder; a suction section that sucks the inside of the centrifugal separator cylinder through the toner recovery section, the suction section having a filter that filters the toner in the sucked airflow; a toner recovery step of recovering toner using a toner recovery device comprising: The amount of the airflow containing the toner introduced into the centrifugal separator cylinder is Qin (m ３ / min) to the suction amount QBD (m ３ / min) is more than 0% and 30% or less, The amount of airflow sucked by the suction unit QBD (m ３ / min) ratio of the filtration area (m ２ ) is 0.4 or more and 4.0 or less, Toner manufacturing method.

2. The amount of airflow Qin (m ３ / min), and the inner diameter d (m) of the centrifugal separator at the airflow introduction position is 5≦Qin / d ２ The method for producing a toner according to claim 1, wherein the toner content satisfies the following formula: ≦500.

3. The amount of airflow sucked by the suction unit QBD (m ３ / min), and the inner diameter d (m) of the centrifugal separator at the airflow introduction position is 0<QBD / d ２ The method for producing a toner according to claim 2, wherein the toner content satisfies the following formula: ≦150.

4. The filtration area A (m ２ ), and the inner diameter d (m) of the centrifugal separator at the airflow introduction position is 0.5≦A / d ２ The method for producing a toner according to claim 3, wherein the ratio satisfies the following: ≦100.

5. 5. The method for producing toner according to claim 1, wherein the toner recovery device has a backwashing unit that backwashes the filtration filter.

6. 6. The method for producing toner according to claim 5, wherein the backwashing unit backwashes the filtration filter at a frequency of 0.5 times / min or more.

7. 7. The method for producing a toner according to claim 5, wherein the filter has a pressure difference between the inside and outside of the filter that is greater than 0 KPa and not greater than 0.5 KPa.

8. When the inner diameter (m) of the centrifugal separator at the airflow introduction position is d, 8. The toner manufacturing method according to claim 1, wherein a distance between a center of a connecting portion of the centrifugal separator and the toner recovery unit and a center of a connecting portion of the toner recovery unit and the suction unit is 0.3d or more and 1.5d or less.

9. When the inner diameter (m) of the centrifugal separator at the airflow introduction position is d, 9. The method for producing toner according to claim 8, wherein the diameter of the connecting portion between the toner recovery portion and the suction portion is 0.3 d or more and 1.5 d or less.

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