JP2006330275A - Method for manufacturing electrostatic charge image developing toner, apparatus for manufacturing electrostatic charge image developing toner, and electrostatic charge image developing toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an electrostatic charge image developing toner with which production of coarse powder is reduced and a coarse powder production level is stabilized. <P>SOLUTION: The method for manufacturing the electrostatic charge image developing toner comprises using an air current type drying machine including main piping having an air current discharge port and an air current ejection port, dispersing and supplying a wet toner into the heating air current supplied from the current ejection port to the main piping, and drying the toner, separating the dry toner obtained by drying from the heating air current, and recovering the toner by a recovering device 20, in which the relationship between the discharge operation cycle time A (minute) of a discharge valve to discharge the dry toner from the recovering device 20 and the time A1 (minute) till the discharge valve performs the first discharge operation after the start of the drying operation of the wet toner is expressed by expression: 2.5×A≤A1≤10.0×A. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing an electrostatic charge image developing toner used when developing an electrostatic latent image formed by electrophotography, an electrostatic charge image developing toner production apparatus, and an electrostatic charge image development obtained thereby. The present invention relates to a toner.

  A method of visualizing image information through an electrostatic charge image such as electrophotography is currently used in various fields. In electrophotography, an electrostatic latent image is formed on a photoreceptor through a charging and exposure process, and the electrostatic latent image is developed with a developer containing an electrostatic charge image developing toner (hereinafter sometimes abbreviated as toner). The toner image is visualized through a process of transferring and fixing the toner image. The developer used here includes a two-component developer comprising a toner and a carrier, and a one-component developer using a magnetic toner or a non-magnetic toner alone.

  In recent years, for the purpose of improving the image quality of images obtained by electrophotography, electrophotographic toners having a particle diameter of 8 μm or less have become mainstream, and many proposals relating to this have been made. As a method for efficiently producing a toner having a small particle diameter, an emulsion polymerization aggregation method (for example, see Patent Documents 1 to 3), a suspension polymerization method (for example, see Patent Documents 4 to 6), a liquid drying method (For example, refer to Patent Document 7 to Patent Document 10).

  Problems common to these wet processes include poor stirring and the generation of coarse powder due to the sticking matter adhering to the reaction vessel and the stirring blade. These coarse powders cause non-uniform intervals between the photosensitive member and the transfer member in the transfer process, that is, easily cause scattering to the non-image area, and further, due to the occurrence of a charging difference due to a particle size difference. This is a major factor that degrades image quality, such as the occurrence of image unevenness. Furthermore, since it causes toner scattering during development, it also causes a decrease in reliability due to in-machine contamination.

  The problem of these toner coarse powders can be improved by removing particles having a volume average particle diameter Dv of 3 times or more, as described in Patent Document 11, for example.

  Examples of the method for removing the toner coarse powder include a method of air classification after the toner is dried and a method of sieving.

  The method of air classification after toner drying uses a solid-gas separator such as a cyclone or bag filter to separate the airflow from the toner, but the plate-like, needle-like irregular coarse powder contained in the raw material, The low-density coarse powder containing various bubbles is difficult to remove by air classification because its own inertia is weak. In addition, in the method of externally adding additives after sieving and sieving, sieving using a net of 25 μm or 20 μm or less is difficult due to the influence of particle adhesion, industrial mass processing is difficult, and practical removal is possible. The average particle size is about 32 μm or more. For the above reasons, in order to effectively remove coarse powder at low cost, a method of sieving in the state of toner particle dispersion is desirable, and this method has been proposed (for example, Patent Documents 11 to 14). .

  In addition, as a device in the drying operation performed after solid-liquid separation of the toner particle dispersion, the material stationary dryer, the material transfer dryer, the material agitation dryer, the infrared dryer, the freeze dryer, the high frequency dryer, Fluidized bed dryers, airflow dryers, and the like are known. Items required for this drying operation are to remove moisture and solvent from the wet toner state after the solid-liquid separation operation, to disperse the toner into primary particles, and to newly originate from toner aggregates and the like. It is not to produce coarse powder.

  As a drying apparatus for achieving these, there is known a method using a loop-type airflow dryer in which wet toner is pulverized and dispersed by high-speed airflow, and primary particles are dried by hot air. In the airflow dryer, the contact area between the particles and the airflow can be increased by crushing and dispersing the wet toner in a high-speed airflow and simultaneously drying the heated dry air while sending it in parallel flow. Therefore, continuous processing is possible, and the drying efficiency is very good. Moisture present between the particles can be instantaneously evaporated without changing the particle size distribution before drying.

  In the toner manufacturing methods described in Patent Document 15, Patent Document 16, Patent Document 17, Patent Document 18, and the like, the moisture content of the water-containing toner cake to be dried is adjusted for the drying method using the airflow dryer. It has been proposed to stably operate this air flow dryer by defining the linear velocity of the hot air stream used for drying, defining the mass of hot air sent per unit time with respect to the amount of water removed from the particles, etc. .

Japanese Patent Laid-Open No. 63-282275 JP-A-6-250439 JP-A-10-26842 Japanese Patent Publication No. 36-10231 Japanese Patent Publication No. 43-10799 Japanese Patent Publication No. 51-14895 JP-A-50-120632 JP 63-25664 A Japanese Patent Laid-Open No. 5-127422 JP-A-8-179556 JP 2000-172007 A JP 2002-196534 A JP 2004-198793 A JP 2004-245990 A JP 2000-292975 A JP 2000-330335 A JP 2001-255696 A JP 2004-109942 A

  However, the toner manufacturing methods described in Patent Document 15, Patent Document 16, Patent Document 17, Patent Document 18 and the like have the following problems. The toner dried by the airflow dryer is entrained in the airflow and then collected by a solid-gas separation device such as a cyclone or a bag filter provided to separate the airflow from the toner. The cyclone and bag filter are separated by exhaust valves such as rotary valves and butterfly valves because they are under the pressure of the exhausted air (minus or plus with respect to atmospheric pressure). Thus, the dried toner can be collected continuously or intermittently. These discharge valves are required to have a sealing property (air tightness). However, when dried toner adheres to the valve, the adhered toner aggregate is crushed by the operation of the valve to become coarse powder. It may end up. Patent Document 15, Patent Document 16, Patent Document 17, and Patent Document 18 are proposals for drying conditions for suppressing coarse powder generated when drying is insufficient and dispersion is insufficient. Is not considered, and the amount of coarse powder in the collected toner is not necessarily stable.

  In addition, there is a method in which after the additive is externally added to the dried toner, the generated coarse powder is sieved and removed. As described above, sieving using a net of 25 μm or 20 μm or less is an industrial method. Therefore, it is necessary to suppress the generation of coarse powder of 25 μm or less by a drying operation.

  The present invention relates to a method for producing an electrostatic image developing toner, an electrostatic image developing toner producing apparatus, and an electrostatic image developing toner that generate little coarse powder and have a stable level of coarse powder generation.

The present invention uses an airflow dryer including a main pipe having an airflow outlet and an airflow outlet to disperse and supply wet toner into a heated airflow supplied from the airflow outlet to the main pipe. A method for producing a toner for electrostatic charge development in which a dry toner obtained by drying is separated from the heated airflow and recovered by a recovery device, wherein the toner is dried from the recovery device in a steady state of the drying operation of the wet toner. The relationship between the discharge operation cycle time A (minute) of the discharge valve for discharging the toner and the time A1 (minute) from the start of the drying operation of the wet toner until the discharge valve performs the first discharge operation is expressed by the following equation. expressed.
2.5 × A ≦ A1 ≦ 10.0 × A

The present invention also relates to a toner manufacturing apparatus for electrostatic charge development, including a main pipe having an air flow outlet and an air outlet, and is wetted in a heated air stream supplied from the air stream outlet to the main pipe. An airflow dryer for supplying toner in a dispersed manner to obtain dry toner, a recovery means for separating the heated airflow and the dry toner, and a discharge means having a discharge valve for discharging the dry toner from the recovery means. The discharge valve discharge operation cycle time A (minute) in the steady state of the wet toner drying operation, and the time A1 from the start of the wet toner dry operation to the discharge valve performing the first discharge operation. The relationship with (minute) is expressed by the following formula.
2.5 × A ≦ A1 ≦ 10.0 × A

  Furthermore, the present invention is an electrostatic image developing toner obtained by the above-described method for producing an electrostatic image developing toner.

  According to the present invention, the wet toner is dispersedly supplied into the heated airflow supplied from the airflow outlet to the main pipe using the airflow dryer including the main pipe having the airflow outlet and the airflow outlet. In the electrostatic charge developing toner manufacturing method in which the dry toner obtained by drying is separated from the heated airflow and recovered by the recovery device, the discharge of the dry toner is discharged from the recovery device in the steady state of the drying operation of the wet toner By defining the relationship between the discharge operation cycle time of the valve and the time from the start of the drying operation of the wet toner until the discharge valve performs the first discharge operation, the generation of coarse powder is reduced and the level of coarse powder generation is stable An electrostatic charge image developing toner manufacturing method, an electrostatic charge image developing toner manufacturing apparatus, and an electrostatic charge image developing toner can be provided.

  Embodiments of the present invention will be described below. In the following description, for convenience of description, in particular, when referring to the toner after being subjected to the drying process, it is referred to as “dry toner”, and when referring to the toner in a wet state before being subjected to the drying process, “ This is referred to as “wet toner”, and may be simply referred to as “toner” when the presence or absence of the drying process is not particularly limited. However, the expression “dry toner” does not necessarily mean a toner in a sufficiently dried state, but means a toner after undergoing a drying process.

<Toner drying process>
An outline of an example of an electrostatic charge developing toner manufacturing apparatus according to this embodiment is shown in FIG. An electrostatic charge developing toner manufacturing apparatus 1 according to the present embodiment includes a loop type airflow dryer 10, a wet toner supplier 12, a rotary feeder 14, an air pushing blower 16, a heater 18, and a collecting unit. A recovery device 20, an exhaust blower 22, and a discharge device 24 as discharge means are provided.

  In the electrostatic charge developing toner manufacturing apparatus 1 shown in FIG. 1, a rotary feeder 14 is provided above the wet toner supply port 28 provided in the main pipe 26 of the loop airflow dryer 10, and the rotary feeder 14 is wet. A toner supplier 12 is connected. In addition, an air pushing blower 16 is connected to the airflow discharge port 30 of the loop type airflow dryer 10 through a heater 18 via a pipe 18, and the airflow discharge port 32 of the loop type airflow dryer 10 is recovered by a pipe 34. A device 20 is connected. An exhaust blower 22 is connected to the recovery device 20 by piping or the like. In addition, a discharge device 24 having a discharge valve is connected to the lower portion of the collection device 20.

  The operation of the electrostatic charge developing toner manufacturing method according to the present embodiment and the operation of the electrostatic charge developing toner manufacturing apparatus 1 will be described. The wet toner, which is a toner cake or a toner slurry obtained by a wet manufacturing method such as an emulsion polymerization aggregation method, is controlled to a desired supply amount by the wet toner supply machine 12, passes through the rotary feeder 14, and then loop type airflow dryer 10. The main pipe 26 is supplied. The dry air used for drying is compressed air sent from the air pushing blower 16 is heated by the heater 18 through which a heat medium such as steam flows, and sent from the air flow outlet 30 to the main pipe 26 of the loop type air flow dryer 10. It is. The wet toner supplied to the loop type airflow dryer 10 is crushed and dispersed by the airflow of heated dry air in the main pipe 26 and simultaneously dried. While the wet toner contains moisture and is heavy, the centrifugal force is high and circulates outside the main pipe 26. However, when the moisture evaporates and becomes light, the centrifugal force becomes low and circulates inside the main pipe 26. Then, the dry toner, which has been lightened by sufficiently evaporating the moisture, is conveyed along with the airflow from the airflow outlet 32 provided inside the main pipe 26. The dry toner exits from the air flow outlet 32, is accompanied by the air flow, is supplied to the recovery device 20 through the pipe 34, and is separated into solid and gas by the recovery device 20. The separated air is exhausted through the exhaust blower 22. On the other hand, the dry toner recovered by the recovery device 20 is discharged by a discharge device 24 having a discharge valve, recovered in a recovery container 36, and sent to the next step, for example, a step of adding and mixing external additives.

  In such a toner drying process, the present inventors have found a situation where the amount of coarse powder in the collected dry toner is not constant. The situation is as follows.

  The wet toner is continuously crushed and dispersed by the loop airflow dryer 10 and dried simultaneously with the dispersion. The dried toner is collected by the collecting device 20 and sent to the next step such as a step of adding and mixing external additives. When this next process is stopped, the supply of the wet toner to the loop type airflow dryer 10 is stopped, and the supply of a heat medium such as steam for heating the air used for drying is stopped as necessary. The operation of the air pusher blower 16 for pushing in the dry air and the exhaust blower 22 for sucking in the air discharged from the dryer are in a so-called idling state. Further, even when the supply of wet toner decreases for some reason or stops, the idling state is similarly entered. Even in this idling state, when the discharge valve provided at the lower part of the recovery device 20 for discharging dry toner from the recovery device 20 operates in the same manner as when wet toner is supplied, There was a lot of coarse powder produced by the operation of the valve. In particular, when a bag filter is used as the collecting device 20, pulse air for backwashing the filter is included in order to wipe off dry toner adhering to the filter. During this time, the dry toner adhering to the filter continued to be discharged, and the portion adhering to the valve became coarse powder and was discharged.

  In addition, there are toners with different colors if they are full color models, and there are also toner varieties with different material compositions depending on the model, but in many cases, a wide variety of toners will be made on one line. . In this case, it is necessary to clean the line in order to prevent contamination between colors or varieties. Bag filters have a higher recovery rate than cyclones, but are difficult to clean because they are equipped with multiple filters that trap dry toner. In order to solve this problem, it is possible to use a side-cut type bag filter in which the filter cartridge can be easily removed. Especially when this type of side-cut type filter is used, the drying operation is started after the line cleaning. However, during the initial stage of the drying operation, that is, while the dried toner is deposited on the filter, the amount of dry toner discharged per hour is equal to the amount of toner supplied per hour (from wet toner amount to moisture amount). It will be less than (subtracted). Even in such a state, a large amount of coarse powder was present in the dried and discharged dry toner.

  From these situations, the inventors considered as follows. Since the discharge valve provided under the recovery device 20 such as a cyclone or a bag filter needs to have a sealing property (air tightness), when the dry toner adheres, the attached dry toner aggregate is caused by the operation of the discharge valve. The body is crushed to produce coarse powder. Therefore, the dry toner is constantly discharged from the collection device 20, that is, a state in which almost the same amount of toner as that supplied to the loop airflow dryer 10 is discharged (this state is referred to as “steady state in this specification). In the “state”, the generated coarse powder is diluted with the dry toner discharged without being rubbed against the valve, and the amount of generated coarse powder with respect to the total amount of discharged dry toner. Becomes lower. On the other hand, as described above, the supply of the wet toner has been reduced or stopped and the dry operation has been started, or the initial state in which the supply of the wet toner has been started, that is, the dry toner has been deposited on the bag filter and supplied. When the amount of dry toner discharged is smaller than the amount of toner discharged, the ratio of coarse powder generated to the total amount of discharged dry toner is high, resulting in a dry toner with a large amount of coarse powder. End up.

  Therefore, in the “steady state” of the drying operation of the wet toner, the discharge operation cycle time A (minute) of the discharge valve for discharging the dry toner, and from the start of the drying operation of the wet toner until the discharge valve performs the first discharge operation. It was found that the ratio of the coarse powder produced by the operation of the discharge valve is kept constant with respect to the total amount of discharged dry toner by defining the relationship with the time A1 (minute).

  That is, in the initial operation state where the amount (speed) of dry toner discharge is small, the discharge operation cycle of the discharge valve that discharges the dry toner from the recovery device 20 is longer than the discharge operation cycle in the steady state to generate coarse powder. The present invention proposes a toner manufacturing method and a manufacturing apparatus in which the generation of coarse powder is reduced and the level of coarse powder generation is stabilized by reducing the original operation. Also, when the supply of wet toner decreases or stops and the idling operation is performed, the operation of the discharge valve of the recovery device is stopped, and when the supply of wet toner is restarted, the amount of dry toner discharged is the same. In the initial state where the (speed) is low, the discharge operation cycle of the discharge valve that discharges the dry toner from the recovery device 20 may be made longer than the discharge operation cycle in the steady state to reduce the operation that generates coarse powder. .

In this embodiment, the discharge operation cycle time A (minute) of the discharge valve for discharging the dry toner in the steady state of the dry operation of the wet toner, and the discharge valve performs the first discharge operation from the start of the dry operation of the wet toner. The relationship with time A1 (minutes) until is expressed by the following formula (1).
2.5 × A ≦ A1 ≦ 10.0 × A (1)

Further, the above formula (1) is preferably represented by the following formula (2), more preferably by the following formula (3).
4.0 × A ≦ A1 ≦ 8.0 × A (2)
5.0 × A ≦ A1 ≦ 7.0 × A (3)

Also, the discharge operation cycle time A (minute) of the discharge valve for discharging the dry toner in the steady state of the drying operation of the wet toner and the discharge operation for the second time after the discharge valve finishes the first discharge operation. It is preferable that the relationship with the time A2 (min) until is expressed by the following formula (4).
1.2 × A ≦ A2 ≦ 7.0 × A (4)

The above formula (4) is preferably represented by the following formula (5).
2.0 × A ≦ A2 ≦ 6.0 × A (5)

  That is, in the present embodiment, in the initial state of the dry operation where the supply of wet toner is low, the time A1 (minutes) from the start of the dry operation of the wet toner until the discharge valve performs the first discharge operation is calculated as the wet toner supply. By reducing the discharge operation cycle time A (minute) of the discharge valve for discharging dry toner in the steady state of the drying operation, the generation of coarse powder generated by rubbing accompanying the valve operation can be effectively reduced. I can do it.

  In the present embodiment, in the initial state of the drying operation where the supply of the wet toner is low, the time A1 (minutes) from the start of the drying operation of the wet toner until the discharge valve performs the first discharge operation, and the discharge valve Is the time A2 (minutes) from the end of the first discharge operation to the second discharge operation, and the discharge operation cycle time A of the discharge valve for discharging the dry toner in the steady state of the wet toner drying operation. By making the time longer (minutes) and further making the time A2 (minutes) shorter than the time A1 (minutes), the generation of coarse powder generated by rubbing accompanying the valve operation can be efficiently reduced.

  In this specification, “the time from the start of the drying operation of the wet toner until the discharge valve performs the first discharge operation” means that the discharge valve discharges “completely” the first time from the start of the wet toner drying operation. The time until the operation is completed, and “the time from when the discharge valve finishes the first discharge operation to the second discharge operation” is the first time after the drying operation of the wet toner is started. This is the time from when the discharge valve finishes the “complete” discharge operation until the second time the discharge valve finishes the “complete” discharge operation. In addition, “the discharge operation cycle time of the discharge valve in the steady state of the drying operation of the wet toner” means that the discharge operation is “completely” immediately before the discharge valve in the steady state of the drying operation of the wet toner starts the discharge operation. The time until the end.

  Here, when A1 <2.5 × A, the ratio of the generated coarse powder is high with respect to the total amount of dry toner discharged, resulting in a dry toner with a lot of coarse powder. End up. In addition, when A1> 10.0 × A, too much dry toner accumulates on the valve, and the discharge performance deteriorates. Therefore, excessive pressure is applied to the toner during discharge, resulting in coarse powder. A lot of dry toner.

  Further, when A2 <1.2 × A, the ratio of the generated coarse powder to the total amount of discharged dry toner becomes high, resulting in a dry toner with a lot of coarse powder. There is a case. In addition, when A2> 7.0 × A, too much dry toner accumulates on the valve, and the discharge performance deteriorates. Therefore, excessive pressure is applied to the toner during discharge, resulting in coarse powder. There may be a lot of dry toner.

  In this embodiment, a known level meter that can be used for the powder system, for example, a level meter such as a capacitance type or a tuning fork type, is installed on the discharge valve, and the supply of wet toner is reduced or stopped, and the idle operation is performed. When the level meter does not detect dry toner for a certain period of time, as in the case where it becomes, the discharge valve may be stopped to reduce the generation of coarse powder generated by rubbing accompanying the valve operation. .

  Further, when the level meter detects a certain amount of dry toner, the discharge valve may be operated to reduce the generation of coarse powder generated by rubbing accompanying the valve operation. This is because a bag filter, particularly a filter cartridge with a horizontal filter cartridge is used for the collecting device 20, and after the line is washed, the dried toner is discharged until the dried toner is deposited on the filter. This is effective when the amount of toner is smaller than the amount of toner supplied per same time (the amount of wet toner minus the amount of water).

  Usually, the actual amount of dry toner accumulated on the bag filter or the accumulated amount of discharged dry toner is grasped in advance, and the discharge operation cycle time A (minute) of the discharge valve for discharging the dry toner is determined. The time A1 (minutes) from the start of the drying operation of the wet toner until the discharge valve performs the first discharge operation is determined to be within the range of the above formula (1), and the discharge operation by the discharge valve is controlled using a timer or the like. By doing so, generation | occurrence | production of the coarse powder produced | generated by the rubbing accompanying valve operation | movement can be decreased. In addition, the time A2 (minutes) from when the discharge valve finishes the first discharge operation to the second discharge operation is determined to fall within the range of the above formula (4), and discharge is performed using a timer or the like. By controlling the discharging operation by the valve, it is possible to reduce the generation of coarse powder generated by rubbing accompanying the valve operation.

  Furthermore, by providing a container or feeder equipped with a load cell or the like under the discharge valve, the actual amount of dry toner discharged can be determined based on the indicated value measured by the load cell or the like. For example, in the case of a butterfly valve, depending on the difference between the supply rate of the toner to be fed into the dryer (subtracting the moisture content of the wet toner) and the discharge rate of the dry toner, more specifically, the cycle of operation. The time from discharge to the next discharge may be adjusted, and in the case of a rotary valve, it may be operated intermittently rather than always, so that coarse powder generated by rubbing associated with valve operation Thus, it is possible to discharge the dried toner without increasing the ratio.

  Further, by linking the operation signal 38 of the wet toner supply machine 12 to the operation condition of the discharge device 24 in the series of operation programs of the drying process, the supply amount of wet toner is reduced, the supply is stopped, and the next process. The operation of the discharge device 24 can be changed when the operation state of the wet toner supply machine 12 is changed due to waiting for the toner.

  The airflow dryer includes a main pipe having an airflow outlet and an airflow outlet, and when the wet toner is dispersedly supplied into the heated airflow supplied from the airflow outlet into the main pipe, the wet toner is heated to the airflow. The structure is not particularly limited as long as it can be dried while being accompanied, and examples include a straight pipe type in addition to a loop type having an annular main pipe, and drying by repeated heating airflow until drying. The loop type is preferable from the viewpoint that an opportunity is obtained and that the configuration of the airflow dryer can be made compact. Further, the number of airflow discharge ports may be one, but may be two or more.

  The airflow outlet 30 shown in FIG. 1 needs to be supplied so that the airflow is blown out from the tangential direction with respect to the main pipe 26 so that the airflow circulates in the fixed direction. The linear velocity of the airflow at the airflow outlet 30 is preferably 30 m / sec or more, and more preferably 50 m / sec or more. As the linear velocity of the air stream increases, the wet toner is transported and circulated in the main pipe 26 in the air stream, and the water is instantly evaporated, and at the same time, the toner is loosened to the primary particles. Here, if the linear velocity of the air flow is less than 30 m / sec, the toner is difficult to be conveyed even if the air flow circulates, and at the same time, the toner may not be loosened while being aggregated. Moreover, the linear velocity of the airflow at the airflow outlet 30 is preferably 250 m / sec or less, and more preferably 240 m / sec or less. If the linear velocity of the air flow exceeds 250 m / sec, the number of times the impact of the wet toner collides with the inner wall of the main pipe 26 and the impact force during the drying process increase, so that great stress is applied to the wet toner, causing toner destruction. Or the surface of the obtained dry toner may cause a surface change such as rubbing.

  The water content of the heated airflow supplied to the main pipe 26 (water content at the airflow outlet 30) is preferably 0.022 kg / kg (DA) or less, more preferably 0.020 kg / kg (DA). The following is preferable. When the water content of the heated airflow exceeds 0.022 kg / kg (DA), it is difficult to quickly dry the wet toner, which may result in an undried product. The water content of the heated airflow is the amount of water vapor contained in the air expressed as a mass ratio [kg / kg (DA)] per 1 kg (DA) of dry air.

  The temperature of the airflow at the airflow outlet 30 is preferably 70 ° C. or higher, and more preferably 80 ° C. or higher. If the temperature of the airflow is less than 70 ° C., the moisture of the wet toner supplied from the wet toner supply port 28 may not be sufficiently evaporated. The higher the temperature of the airflow, the more instant the toner moisture evaporates. Usually, the upper limit of the temperature of the airflow is preferably about 140 ° C, more preferably 120 ° C or less. The drying time of the toner in the loop type airflow dryer 10 is usually within 10 minutes.

  The temperature of the airflow in the recovery device 20 is preferably 60 ° C. or less, and more preferably 55 ° C. or less. If the temperature of the airflow is higher than 60 ° C., the toner may be fused to the collecting device 20 and the toner may be blocked. Further, the temperature of the airflow in the recovery device 20 is preferably 5 ° C. or less from the glass transition point (Tg) of the toner in terms of preventing toner fusion and toner blocking.

  As the recovery device, a solid-gas separator such as a cyclone or a bag filter can be used, but a bag filter is preferable because of a high recovery yield. Moreover, it is more preferable that the filter is a horizontal bag type filter that allows easy removal of the filter cartridge during cleaning.

  As the discharge valve of the discharge device, a known rotary valve, butterfly valve or the like can be used, but the butterfly valve is preferable from the viewpoint of airtightness in consideration of the pressure condition at the time of drying.

  Next, an outline of an example of the collection device 20 and the discharge device 24 provided in the lower portion of the collection device is shown in FIGS.

  FIG. 2 shows an example in which a cyclone 40 is used as the recovery device 20 and a rotary valve 42 is provided in the discharge device 24. The dry toner collected by the cyclone 40 is discharged by the rotary valve 42 provided in the discharge device 24 below the cyclone 40, collected in the collection container 36, and sent to the next process. The operating condition of the rotary valve 42 is a condition determined based on the above formula (1) or the above formulas (1) and (4). In FIG. 2, as the collection container 36, a supply machine that also serves as a collection container for the external additive mixing process, which is the next process, and a discharge device is used. By providing the recovery container 36 with the load cell 44, the actual amount of dry toner discharged from the cyclone 40 can be known. Based on this dry toner discharge speed (indicated by signal 46 in the figure), it is possible to determine the rotational speed adjustment of the rotary valve 42 and the conditions for starting and stopping the operation. Further, by linking the operation signal 38 of the wet toner supply device 12 of FIG. 1 to the operation condition of the rotary valve 42, the operation of the rotary valve 42 is stopped in conjunction with the operation or stop of the wet toner supply device 12. May be.

  When the cyclone 40 is used as the recovery device 20, the recovery efficiency is lowered, and for the purpose of protecting the blower, the bag filter 48 for capturing the toner fine particles that could not be recovered is provided with the exhaust blower 22. You may install between. The fine particles collected by the bag filter 48 are collected in the container 50.

  FIG. 3 shows an example in which a cyclone 40 is used as the recovery device 20 and a butterfly valve 52 is provided in the discharge device 24. Two butterfly valves 52a and 52b are provided above and below the discharge device 24 so that the discharge operation can be repeated continuously, a storage tank 54 and a pressure adjustment valve 56 are provided between the butterfly valves 52a and 52b, and the upper and lower butterfly valves 52a and 52b are provided. The doors are alternately opened and closed. In this example, the storage tank 54 is provided with a level switch 58. The dried toner exits the loop airflow dryer 10 shown in FIG. 1 and is collected by the cyclone 40 through the pipe 34 along with the airflow. First, the upper butterfly valve 52a is opened and the lower butterfly valve 52b is closed, so that dry toner is stored in the storage tank. After closing the upper butterfly valve 52a and adjusting the pressure by the pressure adjusting valve 56, the lower butterfly is operated according to the operating condition determined based on the above equation (1) or the above equations (1) and (4). The valve 52b is opened and discharged to the collection container 36. The lower butterfly valve 52b is closed again, the pressure is adjusted by the pressure adjusting valve 56, the upper butterfly valve 52a is opened, and the operation returns to the operation of accumulating dry toner in the storage tank 54 again.

  The time for opening the lower butterfly valve 52b, the time for adjusting the pressure, and the like include the speed of toner dried per hour, the bulk density of the toner, the size of the storage tank 54, the diameter of the butterfly valve 52, and the like. You just have to take it into consideration. In the present embodiment, for example, when the level switch 58 does not detect the presence of dry toner for a certain period of time, if the operation of discharging to the collection container 36 is stopped, the dry toner is not supplied from the cyclone 40 to the storage tank 54. The butterfly valve 52b does not operate, and the amount of coarse powder generated by the operation of the butterfly valve 52 is minimized. Further, also in this example, the operation signal 38 of the wet toner supplier 12 in FIG. 1 is linked to the operation conditions of the upper and lower butterfly valves 52a and 52b, so that the operation or stop of the wet toner supplier 12 is linked. The operations of the upper and lower butterfly valves 52 a and 52 b can be stopped, and the generation of coarse powder due to the operation of the butterfly valve 52 can be suppressed.

  FIG. 4 shows an example in which a bag filter 62 is used as the collection device 20 and a rotary valve 42 is provided in the discharge device 24. FIG. 5 shows an example in which a bag filter 62 is used as the collection device 20 and a butterfly valve 52 is provided in the discharge device 24. 4 and 5 differ from FIGS. 2 and 3 in the recovery device 20, but the discharging operation by the rotary valve 42 or the butterfly valve 52b is performed according to the above formula (1) or the above formulas (1) and (4). FIG. 2 shows that the determination is based on the operation signal of the wet toner supply device 12, the actual amount signal 46 of the discharged dry toner in the collection container 36, or the detection signal 60 of the level switch 58. , Similar to the example shown in FIG.

  By drying the wet toner in this way, it is possible to obtain a dry toner having a small moisture content and a small amount of coarse powder. Specifically, the amount of coarse powder can be 50 or less, preferably 40 or less, of 2 μg or more of coarse powder in 2 g of dry toner. If the number of coarse powders of 20 μm or more exceeds 2 in 2 g of dry toner, image defects increase when an image is formed.

  Further, the wet toner may be dried so that the water content of the dry toner is 1% by weight or less, more preferably 0.5% by weight or less, and the toner compression ratio is in the range of 0.35 to 0.60. preferable.

  When the water content of the dry toner exceeds 1% by weight, the charge is lowered and the image quality may be fogged. Also, when the compression ratio is less than 0.35, the surface of the dry toner particles is smooth, so that when the dry toner particles remaining on the photoconductor are removed, the image quality defect is caused by the photoconductor stain generated by slipping through the cleaning blade. There is a case. On the other hand, when the compression ratio is 0.60 or more, due to the deterioration of the fluidity of the dry toner, blocking may occur in the developing machine, leading to poor discharge and density fogging.

  In the present embodiment, by setting the operation of the discharge device in the initial stage of operation with a small amount of dry toner to be discharged as a constant condition, the production of toner for developing an electrostatic charge image in which the generation of coarse powder is small and the level of coarse powder generation is stable. A method, a toner manufacturing apparatus for developing an electrostatic charge image, and a toner for developing an electrostatic charge image can be provided. Further, when the supply of the wet toner to be dried is reduced or stopped, the operation of the discharge device that discharges the dry toner to the collection container can be linked to reduce or stop the number of discharge operations. Thereby, it is possible to prevent image quality deterioration and reliability deterioration due to scattering in non-image portions and image unevenness due to toner coarse powder.

  The electrostatic charge image developing toner according to this embodiment, that is, the dry toner has a volume average particle diameter D50v in the range of 4 μm to 8 μm. If the volume average particle diameter D50v of the toner is smaller than 4 μm, the chargeability is insufficient and scattering to the surroundings occurs to cause image fogging, or the toner that could not be transferred could not be sufficiently cleaned, resulting in filming. It is not preferable because it causes it. On the other hand, if the volume average particle diameter D50v exceeds 8 μm, the resolution of the image is lowered and it is difficult to achieve high image quality.

  The volume average particle size distribution index GSDv of the electrostatic image developing toner according to this embodiment is 1.27 or less, preferably 1.25 or less. When GSDv exceeds 1.27, the particle size distribution is not sharp, resolution is deteriorated, and image defects such as toner scattering and fogging are caused.

The volume average particle diameter D50v and the volume average particle size distribution index GSDv can be obtained as follows. For example, the volume with respect to the particle size range (channel) divided based on the particle size distribution of the toner measured with a measuring instrument such as Coulter Counter TAII (manufactured by Nikka Kisha Co., Ltd.) or Multisizer II (manufactured by Nikka Kisha Co. Ltd.) Draw the cumulative distribution from the small diameter side of each number, the particle size to be accumulated 16% is volume D16v, several D16p, the particle size to be accumulated 50% is volume D50v, the number D50p, the particle size to be accumulated 84% is volume D84v and number D84p are defined. At this time, D50v represents the volume average particle diameter, and the volume average particle size distribution index (GSDv) is determined as (D84v / D16v) ^1/2 . In addition, (D84p / D16p) ^1/2 represents a number average particle size distribution index (GSDp).

In addition, the shape factor SF1 represented by the following formula of the toner for developing an electrostatic charge image according to the exemplary embodiment is in the range of 110 to 140, and preferably in the range of 115 to 130.
SF1 = (ML ² / A) × (π / 4) × 100
[In the above formula, ML represents the maximum toner length (μm), and A represents the projected area (μm ² ) of the toner. ]
When the toner shape factor SF1 is smaller than 110 or exceeds 140, it is impossible to obtain excellent chargeability, cleaning property, and transferability over a long period of time.

In addition, shape factor SF1 was measured as follows using a Luzex image analyzer (manufactured by Nireco Corporation, FT). First, an optical microscope image of the toner dispersed on the slide glass is taken into a Luzex image analyzer through a video camera, and the maximum length (ML) and projected area (A) of 50 or more toners are measured. (ML ² / A) × (π / 4) was calculated, and the average value was calculated as the shape factor SF1.

<Components of toner>
As the electrostatic charge image developing toner in this embodiment, a known toner mainly composed of a binder resin and a colorant can be used. That is, toner binder resins include styrenes such as styrene and chlorostyrene; monoolefins such as ethylene, propylene, butylene, and isobutylene; vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, methyl acrylate, Esters of α-methylene aliphatic monocarboxylic acids such as ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate; vinylmethyl Examples include vinyl ethers such as ether, vinyl ethyl ether and vinyl butyl ether; homopolymers or copolymers of vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropenyl ketone. Typical binder resins include polystyrene, styrene / alkyl acrylate copolymer, styrene / alkyl methacrylate copolymer, styrene / acrylonitrile copolymer, styrene / butadiene copolymer, styrene / maleic anhydride copolymer. Examples thereof include coalescence, polyethylene, and polypropylene. Further examples include polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, and paraffin waxes.

  Colorants include carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green, oxalate, lamp black, rose bengal, etc. It can be illustrated as an example. As a dispersion method of these colorants, any method such as a rotary shear type homogenizer, a ball mill having a medium, a sand mill, a high-pressure disperser, an ultrasonic disperser, etc. can be adopted, and there are no restrictions. Is not to be done.

  In addition to the binder resin and the colorant, the toner for developing an electrostatic image in the exemplary embodiment includes various known additives such as a release agent, a magnetic material, a charge control agent, and inorganic fine particles depending on the purpose. Etc. may be contained.

  Examples of mold release agents include low molecular weight polyolefins such as polyethylene, polypropylene and polybutene; silicones having a softening point upon heating; fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide and stearic acid amide; Plant waxes such as ester wax, carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil, etc .; animal waxes such as beeswax; montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, fisher Mention may be made of mineral waxes such as Tropsch wax; petroleum waxes; and their modified products.

  These release agents are dispersed in water together with ionic surfactants, polymer electrolytes such as polymer acids and polymer bases, and are homogenizers and pressure discharge type dispersers that can be heated to the melting point or higher and impart strong shear. It is possible to prepare a fine particle dispersion of 1 μm or less.

  Examples of the magnetic material include metals such as ferrite, magnetite, reduced iron, cobalt, nickel, and manganese, alloys thereof, and compounds containing these metals.

  Examples of the charge control agent may include various commonly used charge control agents such as quaternary ammonium salts, nigrosine compounds, dyes composed of complexes of aluminum, iron, chromium, and triphenylmethane pigments. However, a charge control agent that is difficult to dissolve in water is suitable for controlling the ionic strength that affects the stability during aggregation and fusion integration and reducing wastewater contamination.

  Examples of inorganic fine particles to be added wet include silica, alumina, titania, calcium carbonate, magnesium carbonate, and tricalcium phosphate, all of which are usually used as external additives on the toner surface, such as ionic surfactants and It can be dispersed in a polymer acid or a polymer base and added wet.

  Surfactants used in emulsion production, seed polymerization, pigment dispersion, resin particles, release agent dispersion, aggregation, or stabilization thereof in the toner production process include sulfate ester, sulfonate, and phosphate ester types. , Anionic surfactants such as soaps, and cationic surfactants such as amine salt types and quaternary ammonium salt types, and also polyethylene glycols, alkylphenol ethylene oxide adducts, polyhydric alcohols, etc. It is also effective to use a nonionic surfactant in combination.

  The external additive used in the toner for developing an electrostatic charge image according to this embodiment is not particularly limited except that at least one kind of spherical inorganic fine particles is added, and known external additives such as inorganic fine particles and organic fine particles are added. Among them, inorganic fine particles such as silica, titania, alumina, cerium oxide, strontium titanate, calcium carbonate, magnesium carbonate and calcium phosphate, fluorine-containing resin fine particles, silica-containing resin fine particles and nitrogen-containing can be used. Organic resin fine particles such as resin fine particles are preferred. Moreover, you may surface-treat on the surface of an external additive according to the objective. Examples of the surface treatment agent include a silane compound, a silane coupling agent, and a silicone oil for performing a hydrophobic treatment.

  The toner for developing an electrostatic charge image according to the exemplary embodiment is manufactured by a wet manufacturing method such as an emulsion polymerization aggregation method, a suspension polymerization method, or a liquid drying method. The method of forming the toner by the emulsion polymerization aggregation method includes an emulsification process in which a binder resin, a colorant, and the like are emulsified to form emulsion particles (droplets), and an aggregation of the emulsion particles (droplets). And a fusion step of fusing the aggregates to heat fusion. Further, the wet toner obtained by these wet manufacturing methods is a toner cake or a toner slurry, and the water content thereof is usually 15% by mass to 50% by mass.

  Hereinafter, although an example and a comparative example are given and the present invention is explained more concretely in detail, the present invention is not limited to the following examples.

[Production of wet toner]
<Preparation of resin fine particle dispersion>
Styrene (manufactured by Wako Pure Chemical Industries) 320 parts by mass n-butyl acrylate (manufactured by Wako Pure Chemical Industries) 80 parts by mass β-carboxyethyl acrylate (manufactured by Rhodia Nikka) 9 parts by mass 1,10-decanediol diacrylate (manufactured by Shin-Nakamura Chemical) 1 .5 parts by mass Dodecanethiol (manufactured by Wako Pure Chemical Industries, Ltd.) 2.7 parts by mass

  The above is mixed and dissolved, dissolved in 550 parts by mass of ion-exchanged water containing 4 parts by mass of the anionic surfactant Dowfax (manufactured by Dow Chemical Japan), further dispersed and emulsified in a stirred tank, and slowly stirred for 10 minutes. While stirring and mixing, 50 parts by mass of ion-exchanged water in which 6 parts by mass of ammonium persulfate was dissolved was added. Next, after sufficiently replacing nitrogen in the system, the stirring tank jacket was heated while stirring in the stirring tank until the temperature in the tank reached 70 ° C., and emulsion polymerization was continued for 5 hours. As a result, a resin particle dispersion having a volume average particle size of 234 nm, a solid content of 42.9%, an onset glass transition point of 50.8 ° C., a weight average molecular weight (Mw) of 31800, and a number average molecular weight (Mn) of 10200 was obtained.

<Preparation of colorant particle dispersion>
Phthalocyanine pigment (manufactured by Dainichi Seika Co., Ltd., PVFASTBLUE) 90 parts by mass Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen R) 10 parts by mass Deionized water 240 parts by mass

  The above components were mixed in a stirring tank and dispersed using an optimizer HJP-25008 (manufactured by Sugino Machine Co., Ltd.) set at a dispersion pressure of 196 MPa to prepare a colorant particle dispersion. The volume average particle diameter of the colorant in the colorant dispersion was 118 nm.

<Preparation of release agent dispersion>
Paraffin wax (Nippon Seiwa Co., Ltd., HNPO190: melting point 85 ° C.) 50 parts by mass Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen R) 7.5 parts by mass Ion-exchanged water 200 parts by mass

  The above components were heated to 95 ° C. and dispersed using a homogenizer, and then dispersed with a dyno mill to obtain a wax dispersion. The volume average particle size of the dispersed wax was 245 nm.

  Microtrac (manufactured by Nikkiso Co., Ltd., Microtrac UPA9340) was used for volume average particle size measurement of these resin particle dispersion, colorant dispersion, and release agent dispersion. The weight average molecular weight and the number average molecular weight were determined by molecular weight measurement (polystyrene conversion) by gel permeation chromatography (GPC) method of tetrahydrofuran (THF) soluble matter. The glass transition point was determined by differential scanning calorimetry (DSC) using a differential scanning calorimeter (device name: DSC6200 type) manufactured by Seiko Instruments Inc.

<Preparation of toner particles>
(Aggregation process)
Ion-exchanged water 400 parts by weight Resin particle dispersion 240 parts by weight Colorant dispersion 44 parts by weight Release agent dispersion 56 parts by weight Inorganic fine particle dispersion (Nissan Chemical Co., Snowtex OL) 12 parts by weight Inorganic fine particle dispersion ( 10 parts by mass, manufactured by Nissan Chemical Co., Snowtex OS)

After the above mixed components are put into a stirring tank and thoroughly mixed and dispersed with a homogenizer,
Flocculant [manufactured by Asada Chemical Co., Ltd., polyaluminum chloride] 0.5 parts by mass Ion-exchanged water 100 parts by mass of the mixed solution was added over 10 minutes while stirring the stirring tank, and after the addition was completed, slowly to 40 ° C. Heated and held for 30 minutes, then heated to 49 ° C. After holding at 49 ° C. for 40 minutes, the volume average particle diameter was measured with a Coulter counter (Multisizer 2 manufactured by Coulter Inc.), and it was confirmed that 4.6 μm aggregated particles were formed. Further, the temperature of the heating jacket was raised and held at 52 ° C. for 40 minutes.

(Adhesion process)
To the dispersion containing the aggregated particles prepared above, 65 parts by mass of the resin particle dispersion was further slowly added, and the temperature of the heating jacket was raised and maintained at 53 ° C. for 1 hour. With respect to the obtained adhered particles, the volume average particle diameter was measured with a Coulter counter (Multisizer 2 manufactured by Coulter, Inc.), and it was 5.5 μm.

(Fusion process)
Next, a 1 mol / liter aqueous sodium hydroxide solution was added so that the pH was 6.0, and then the mixture was gently heated to 85 ° C. and kept for 60 minutes while continuing stirring. Thereafter, the mixture was heated to 96 ° C., a 1 mol / liter nitric acid aqueous solution was added until pH 5.0, and the mixture was held for 5 hours. Thereafter, the obtained toner slurry was cooled to 40 ° C. The obtained toner had a volume average particle diameter D50v of 5.5 μm, a volume average particle size distribution index GSDv of 1.21, and a shape factor SF1 of 132. Further, this slurry was subjected to a sieving treatment with a 15 μm mesh, and then filtered with a filter press (manufactured by Tokyo Engineering Co., Ltd.). With respect to 100 parts by mass of the obtained colorant resin fine particles, 500 parts by mass of ion exchange water (conductivity of 2 μS or less) is passed through the toner in the filter press apparatus, and subsequently 1 mol / liter in 300 parts by mass of ion exchange water. Then, acid washing water added with an aqueous nitric acid solution until pH 3.0 is passed, and further 400 parts by mass of ion-exchanged water is passed through, followed by squeezing and dehydrating to obtain a toner cake having a moisture content of 37%. The moisture content is based on the amount of moisture, and was determined by measuring 20 minutes at 105 ° C. using MA30 manufactured by Sartorius. This toner cake was pulverized with Landel Mill RM-1 (manufactured by Tokuju Factory) to obtain a wet toner as a dry raw material.

[Production of dry toner]
(Preliminary experiment 1)
As a wet toner supply device, a loss-in-weight feeder (manufactured by Kuma Engineering Co., Ltd., type 602) is used as a loop type airflow dryer, and a flash jet dryer type 2 (manufactured by Seishin Enterprise) is used. Was 132 m ³ / hr, the supply amount of wet toner was set to 5.2 kg / hr on the basis of dry toner, and the airflow outlet temperature was set to 45 ° C. The dried toner collection device uses a bag filter [cartridge collector 2DF4 type (manufactured by Nippon Donaldson Co., Ltd.)]. Both the inner surface and the cartridge are sprayed with high-pressure air and then dried. I went to. As for the discharge device, two butterfly valves (manufactured by Sakai Valve Co., Ltd.) with pneumatic actuators are arranged up and down, the storage tank between the butterfly valves is at a position where the effective capacity is 2L, and the toner is about 1L as a tuning fork type level switch (Sakura) Endless Co., Ltd. FTM31) was installed. A loss-in-weight feeder (Model 610, manufactured by Kuma Engineering Co., Ltd.) is installed at the bottom of this discharge device, the external additive mixing unit for the next process is set to 6 kg, and dry toner is measured in the container. I tried to do it. When the drying operation was started under these conditions, the level switch did not detect the dried toner for 5 minutes after the supply of the wet toner was started. In other words, the amount of dry toner discharged was less than 1 L (approximately 300 g as dry toner) with most of the toner adhering to the filter cartridge and the inner surface of the bag filter. After 60 minutes, the level switch is in a state of detecting once every 3.5 minutes, and the butterfly valve is discharged once every 3.5 minutes. The drying operation was continued until 6 batches of the external additive mixing treatment were secured.

Example 1
As a wet toner supply machine, a loss-in-weight feeder (manufactured by Kuma Engineering Co., Ltd., model 602) is used as in the preliminary experiment 1, and a flash jet dryer type 2 (manufactured by Seishin Enterprise) is used as a loop type airflow dryer. The air flow for drying was set to 132 m ³ / hr, the supply amount of wet toner was set to 5.2 kg / hr on the basis of dry toner, and the temperature of the air flow outlet was set to 45 ° C. The dried toner collection device uses a bag filter [cartridge collector 2DF4 type (manufactured by Nippon Donaldson Co., Ltd.)]. Both the inner surface and the cartridge are sprayed with high-pressure air and then dried. I went to. As for the discharge device, two butterfly valves (manufactured by Sakai Valve Co., Ltd.) equipped with pneumatic actuators were arranged vertically, and the storage tank between the butterfly valves had an effective capacity of 2L. A loss-in-weight feeder (Model 610, manufactured by Kuma Engineering Co., Ltd.) is installed at the bottom of this discharge device, the external additive mixing unit for the next process is set to 6 kg, and dry toner is measured in the container. I tried to do it. Based on the result of the preliminary experiment 1, the time A1 from the start of the drying operation of the wet toner until the butterfly valve is completely opened (the discharge operation is finished) is 8.75 minutes, and the butterfly valve is completely opened at the first time. The time A2 from the opening to the second full opening (the end of the discharge operation) is 4.2 minutes. After the third butterfly valve operation, the butterfly valve discharge operation cycle time A is set to 3.5 minutes. The drying operation was performed. The drying operation was continued until 6 batches of the external additive mixing treatment were secured.

  Six batches of the dry toner thus obtained were subjected to external additive mixing treatment using a Henschel mixer. As an external additive mixing device, a Henschel mixer FM75J / I manufactured by Mitsui Mining Co., Ltd. equipped with Zo blades and Bo blades as mixing blades was used. 6 kg of dry toner weighed in the above collection container and 60 g of hydrophobic silica (volume average particle size: 0.10 μm) as an additive were mixed. The upper blade tip peripheral speed was 40 m / sec, and the mixing time was 20 minutes.

<Evaluation of toner after treatment>
For each of the processing batches, 2 g of the toner subjected to the external additive mixing treatment was sampled and sieved with a 20 μm mesh sieve, and the number of coarse powder remaining on the sieve was counted.

Further, the toner subjected to the external additive mixing treatment is applied to a ferrite carrier having a volume average particle diameter of 50 μm coated with 1.0% by mass of polymethyl methacrylate (manufactured by Soken Chemical Co., Ltd., weight average molecular weight = 80000). The above-mentioned externally added toner was weighed so that the concentration became 6.0% by mass, and a developer was prepared by stirring and mixing with a ball mill for 5 minutes. Using the obtained developer, a halftone image was prepared using a Docu Center Color 400CP remodeling machine manufactured by Fuji Xerox Co., Ltd. so that the amount of toner paste was 0.3 g / m ^2. Evaluated by criteria. In addition, Fuji Xerox J paper was used as the paper.
◎: Halftone unevenness is not seen at all ○: Halftone unevenness is slightly seen △: Halftone unevenness is seen ×: Many halftone unevenness is seen

Also, using the obtained developer, a Docu Center Color 400CP remodeling machine manufactured by Fuji Xerox Co., Ltd. in a high temperature and high humidity environment (28 ° C., 85% RH) and a low temperature and low humidity environment (10 ° C., 30% RH). A copy test was performed with a character image having an image area ratio of 3%, and an image quality evaluation of 5000 sheets was performed according to the following criteria. As a result, it was confirmed that good images could be obtained without fogging and toner scattering in both environments. The results are shown in Table 1.
◎: Image quality defects are not observed at all ○: Image quality defects are slightly observed △: Image quality defects are observed ×: Image quality defects are often observed

(Example 2)
In Example 1, the time A1 from the start of the drying operation of the wet toner until the butterfly valve opens for the first time is 8.75 minutes, and the time A2 from when the butterfly valve is fully opened for the first time to fully open for the second time A2 After 6.3 minutes and the third butterfly valve operation, dry toner was obtained in the same manner as in Example 1 except that the butterfly valve discharge operation cycle time A was 3.5 minutes. Six batches of these dry toners were mixed in a Henschel mixer as in Example 1. The obtained toner was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 3)
In Example 1, the time A1 from the start of the drying operation of the wet toner until the butterfly valve opens for the first time is 8.75 minutes, and the time A2 from when the butterfly valve is fully opened for the first time to fully open for the second time A2 8.4 minutes after the third butterfly valve operation, a dry toner was obtained in the same manner as in Example 1 except that the butterfly valve discharge operation cycle time A was 3.5 minutes. Six batches of these dry toners were mixed in a Henschel mixer as in Example 1. The obtained toner was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 4
In Example 1, the time A1 from the start of the drying operation of the wet toner to the first opening of the butterfly valve is 14.0 minutes, the time A2 from the first opening of the butterfly valve to the second opening completely. 4.2 minutes after the third butterfly valve operation, dry toner was obtained in the same manner as in Example 1 except that the butterfly valve discharge operation cycle time A was 3.5 minutes. Six batches of these dry toners were mixed in a Henschel mixer as in Example 1. The obtained toner was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 5)
In Example 1, the time A1 from the start of the drying operation of the wet toner to the first opening of the butterfly valve is 14.0 minutes, the time A2 from the first opening of the butterfly valve to the second opening completely. After 6.3 minutes and the third butterfly valve operation, dry toner was obtained in the same manner as in Example 1 except that the butterfly valve discharge operation cycle time A was 3.5 minutes. Six batches of these dry toners were mixed in a Henschel mixer as in Example 1. The obtained toner was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 6)
In Example 1, the time A1 from the start of the drying operation of the wet toner to the first opening of the butterfly valve is 14.0 minutes, the time A2 from the first opening of the butterfly valve to the second opening completely. 8.4 minutes after the third butterfly valve operation, a dry toner was obtained in the same manner as in Example 1 except that the butterfly valve discharge operation cycle time A was 3.5 minutes. Six batches of these dry toners were mixed in a Henschel mixer as in Example 1. The obtained toner was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 7)
In Example 1, the time A1 from the start of the drying operation of the wet toner until the butterfly valve opens for the first time is 19.25 minutes, the time A2 from when the butterfly valve is fully opened to the first time until the butterfly valve is completely opened A2 4.2 minutes after the third butterfly valve operation, dry toner was obtained in the same manner as in Example 1 except that the butterfly valve discharge operation cycle time A was 3.5 minutes. Six batches of these dry toners were mixed in a Henschel mixer as in Example 1. The obtained toner was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 8)
In Example 1, the time A1 from the start of the drying operation of the wet toner until the butterfly valve opens for the first time is 19.25 minutes, the time A2 from when the butterfly valve is fully opened to the first time until the butterfly valve is completely opened A2 After 6.3 minutes and the third butterfly valve operation, dry toner was obtained in the same manner as in Example 1 except that the butterfly valve discharge operation cycle time A was 3.5 minutes. Six batches of these dry toners were mixed in a Henschel mixer as in Example 1. The obtained toner was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 9
In Example 1, the time A1 from the start of the drying operation of the wet toner until the butterfly valve opens for the first time is 19.25 minutes, the time A2 from when the butterfly valve is fully opened to the first time until the butterfly valve is completely opened A2 8.4 minutes after the third butterfly valve operation, a dry toner was obtained in the same manner as in Example 1 except that the butterfly valve discharge operation cycle time A was 3.5 minutes. Six batches of these dry toners were mixed in a Henschel mixer as in Example 1. The obtained toner was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 10)
In Example 1, the time A1 from the start of the drying operation of the wet toner until the butterfly valve opens for the first time is 35 minutes, and the time A2 from when the butterfly valve is fully opened for the first time to fully open for the second time is 24. After the third butterfly valve operation for 5 minutes, a dry toner was obtained in the same manner as in Example 1 except that the butterfly valve discharge operation cycle time A was set to 3.5 minutes. Six batches of these dry toners were mixed in a Henschel mixer as in Example 1. The obtained toner was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 11)
In Example 1, the time A1 from the start of the drying operation of the wet toner to the time when the butterfly valve opens for the first time is 35 minutes, and the time A2 from when the butterfly valve is fully opened to the second time until the butterfly valve is fully opened is 4 After the second butterfly valve operation for 2 minutes, a dry toner was obtained in the same manner as in Example 1 except that the butterfly valve discharge operation cycle time A was set to 3.5 minutes. Six batches of these dry toners were mixed in a Henschel mixer as in Example 1. The obtained toner was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 12)
In Example 1, the time A1 from the start of the drying operation of the wet toner until the butterfly valve opens for the first time is 8.75 minutes, and the time A2 from when the butterfly valve is fully opened for the first time to fully open for the second time A2 24.5 minutes after the third butterfly valve operation, a dry toner was obtained in the same manner as in Example 1 except that the butterfly valve discharge operation cycle time A was 3.5 minutes. Six batches of these dry toners were mixed in a Henschel mixer as in Example 1. The obtained toner was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 13)
In Example 1, the time A1 from the start of the drying operation of the wet toner to the first opening of the butterfly valve is 14.0 minutes, the time A2 from the first opening of the butterfly valve to the second opening completely. 3.85 minutes After the third butterfly valve operation, dry toner was obtained in the same manner as in Example 1 except that the butterfly valve discharge operation cycle time A was 3.5 minutes. Six batches of these dry toners were mixed in a Henschel mixer as in Example 1. The obtained toner was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 14)
In Example 1, the time A1 from the start of the drying operation of the wet toner to the first opening of the butterfly valve is 14.0 minutes, the time A2 from the first opening of the butterfly valve to the second opening completely. 26 minutes after the third butterfly valve operation, a dry toner was obtained in the same manner as in Example 1 except that the butterfly valve discharge operation cycle time A was set to 3.5 minutes. Six batches of these dry toners were mixed in a Henschel mixer as in Example 1. The obtained toner was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 1)
In Example 1, the time A1 from the start of the drying operation of the wet toner until the butterfly valve opens for the first time is 8.4 minutes, and the time A2 from when the butterfly valve is fully opened for the first time to when the butterfly valve is fully opened is A2. After 6.3 minutes and the third butterfly valve operation, dry toner was obtained in the same manner as in Example 1 except that the butterfly valve discharge operation cycle time A was 3.5 minutes. Six batches of these dry toners were mixed in a Henschel mixer as in Example 1. The obtained toner was evaluated in the same manner as in Example 1. The results are shown in Table 2.

(Comparative Example 2)
In Example 1, the time A1 from the start of the drying operation of the wet toner to the time when the butterfly valve opens for the first time is 38 minutes, and the time A2 from when the butterfly valve is fully opened to the second time until the butterfly valve is fully opened is 4 After the second butterfly valve operation for 2 minutes, a dry toner was obtained in the same manner as in Example 1 except that the butterfly valve discharge operation cycle time A was set to 3.5 minutes. Six batches of these dry toners were mixed in a Henschel mixer as in Example 1. The obtained toner was evaluated in the same manner as in Example 1. The results are shown in Table 2.

(Preliminary experiment 2)
The same wet toner, dryer and recovery device, drying conditions, and external additive mixing treatment as in Preliminary Experiment 1 were performed. A rotary feeder (manufactured by Toyo Chemical Industry Co., Ltd., RVH100S) was used as the discharge device. When the wet toner supply is started, the rotary valve is rotated at intervals of 4 minutes, and the recovery amount of the loss-in-weight feeder provided under the rotary valve is 3/4 or less of the wet toner supply speed of 5.2 kg / h. The rotary valve operation was stopped 0.5 minutes after the rotation. For about 12 minutes from the start of the supply of the wet toner, the speed was lower than this value, and only 0.1 kg of dry toner was discharged. Since then, the discharge rate was almost constant in the range of 5.2 ± 0.2 kg / hr as dry toner. Therefore, the rotary valve continued to discharge every 4 minutes and mixed external additives. The drying operation was continued until 6 batches of dry toner were secured.

(Example 15)
The same wet toner, dryer and recovery device, drying conditions, and external additive mixing treatment as in Preliminary Experiment 1 were performed. As a discharging device, a rotary feeder (Toyo Kako Co., Ltd., RVH100S) was used as in the preliminary experiment 2. Based on the result of Preliminary Experiment 2, the time A1 from the start of the drying operation of the wet toner until the rotary valve starts rotating until the first complete discharge operation (until the discharge operation is completed) is 16.0 minutes, 1 The time A2 from the end of the discharge operation of the rotary valve until the complete discharge operation of the second time (until the end of the discharge operation) is 7.2 minutes. The drying operation was performed with the valve discharge operation cycle time A set to 4 minutes. The drying operation was continued until 6 batches of the external additive mixing treatment were secured. Six batches of these dry toners were mixed in a Henschel mixer as in Example 1. The obtained toner was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 3)
In Example 15, the time A1 from the start of the drying operation of the wet toner until the rotary valve starts rotating until the first complete discharge operation is 9.6 minutes, after the rotary valve finishes the first discharge operation. The time A2 until the second complete discharge operation is 4.4 minutes, and after the third discharge valve operation, the discharge operation cycle time A of the rotary valve is 4.0 minutes. A dry toner was obtained in the same manner. Six batches of these dry toners were mixed in a Henschel mixer as in Example 1. The obtained toner was evaluated in the same manner as in Example 1. The results are shown in Table 2.

(Comparative Example 4)
In Example 15, a dry toner was obtained in the same manner as in Example 1 except that the discharge operation cycle time A of the rotary valve was always set to 4.0 minutes. Six batches of these dry toners were mixed in a Henschel mixer as in Example 1. The obtained toner was evaluated in the same manner as in Example 1. The results are shown in Table 2.

  As can be seen from Table 1, the discharge operation cycle time A of the discharge valve for discharging the dry toner from the collecting device in the steady state of the dry operation of the wet toner, and the discharge valve is discharged for the first time from the start of the dry operation of the wet toner. In Examples 1 to 15 in which the relationship of the time A1 until operation satisfies the above formula (1), the number of coarse powder is small, halftone unevenness, image quality evaluation at high temperature and high humidity, and image quality evaluation at low temperature and low humidity. It was good. Moreover, Examples 4-9 which satisfy | fill said Formula (2), especially Examples 7-9 which satisfy | fill said Formula (3) were all favorable evaluation results. Further, compared with Examples 4 to 6 that satisfy the above formula (2) and further satisfy the above formula (4), Examples 13 and 14 that satisfy the above formula (2) but do not satisfy the above formula (4) are slightly different. The evaluation result was inferior. On the other hand, Comparative Examples 1 to 4 that did not satisfy the above formula (1) had a large number of coarse powders, and the halftone unevenness, the image quality evaluation at high temperature and high humidity, and the image quality evaluation at low temperature and low humidity were also poor.

1 is a schematic configuration diagram illustrating an example of an electrostatic charge developing toner manufacturing apparatus according to an embodiment of the present invention. It is a schematic structure figure showing an example of a recovery device and a discharge device concerning an embodiment of the present invention. It is a schematic block diagram which shows the other example of the collection | recovery apparatus and discharge apparatus which concern on embodiment of this invention. It is a schematic block diagram which shows the other example of the collection | recovery apparatus and discharge apparatus which concern on embodiment of this invention. It is a schematic block diagram which shows the other example of the collection | recovery apparatus and discharge apparatus which concern on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Toner production apparatus for electrostatic charge development, 10 loop type airflow type dryer, 12 wet toner supply machine, 14 rotary feeder, 16 air pushing blower, 18 heater, 20 collection device, 22 exhaust blower, 24 discharge device, 26 Piping, 28 Wet toner supply port, 30 Air flow discharge port, 32 Air flow discharge port, 34 Piping, 36 Recovery container, 38 Operation signal, 40 Cyclone, 42 Rotary valve, 44 Load cell, 46 signal, 48 Bag filter, 50 container, 52a , 52b Butterfly valve, 54 Storage tank, 56 Pressure adjustment valve, 58 Level switch, 60 Detection signal, 62 Bag filter.

Claims (3)

By using an airflow dryer including a main pipe having an airflow outlet and an airflow outlet, wet toner is dispersedly supplied into the heated airflow supplied from the airflow outlet to the main pipe and dried. A method for producing a toner for developing an electrostatic charge, wherein the obtained dry toner is separated from the heated air stream and collected by a collecting device,
A discharge operation cycle time A (minute) of the discharge valve for discharging the dry toner from the recovery device in the steady state of the wet toner drying operation, and the first discharge operation of the discharge valve from the start of the wet toner drying operation A method for producing a toner for developing electrostatic charge, characterized in that the relationship with the time A1 (minutes) until the charge is expressed by the following formula:
2.5 × A ≦ A1 ≦ 10.0 × A An electrostatic charge developing toner manufacturing apparatus comprising:
An airflow dryer that includes a main pipe having an airflow outlet and an airflow outlet, and obtains dry toner by dispersing and supplying wet toner in a heated airflow supplied from the airflow outlet to the main pipe;
A collecting means for separating the heated air stream and the dry toner;
Discharging means having a discharge valve for discharging dry toner from the collecting means;
Have
A discharge operation cycle time A (minute) of the discharge valve in a steady state of the wet toner drying operation, and a time A1 (minute) from the start of the wet toner drying operation until the discharge valve performs the first discharge operation. ) Is represented by the following formula: a method for producing an electrostatic charge developing toner.
2.5 × A ≦ A1 ≦ 10.0 × A   An electrostatic image developing toner obtained by the method for producing an electrostatic image developing toner according to claim 1.

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