JPH09190017A - Electrophotographic carrier manufacturing equipment - Google Patents

Abstract

(57) An object of the present invention is to provide an electrophotographic carrier manufacturing apparatus capable of easily forming a high-quality coating on the surface of a carrier core material. SOLUTION: In a carrier manufacturing apparatus in which the surface of a carrier core material is coated with a rolling fluidized bed in a granulation cylinder, the carrier fluid rises from below the rolling fluidized bed along the inner wall of the granulation cylinder. A rotating disk plate for supplying heated air is provided, and the rolling fluidized bed is prevented from rising and the agglomerated particles are crushed to form a swirling flow above the rolling fluidized bed and A secondary air inflow pipe for supplying air having a temperature higher than that of the heated air introduced through the disc plate is disposed, and further, in the granulation cylinder, above the central portion thereof, to the exhaust pipe by mechanical force or aerodynamic force. A carrier manufacturing apparatus for electrophotography, characterized in that a classification blade for rotating and dispersing a resin mist and a coating carrier is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing apparatus for producing electrophotographic carriers with high efficiency.

[0002]

2. Description of the Related Art Granulators have been widely introduced since 1970, mainly in the pharmaceutical and food industries, because they can perform small-quantity multi-product production, mixing, granulation, and drying processes in the same container. In addition, the social boundaries required for granulated products are such that for small-quantity, high-mix production, granulated products such as particle size, density, and shape can be obtained arbitrarily, and mixing, granulation, coating, and drying can be performed by a single facility. Therefore, there has been a demand for a multi-functional FA automated unmanned system capable of arbitrarily obtaining the above-described quality and a combined operation capable of selecting arbitrary steps. In response to these demands, each device manufacturer has been developing and commercializing a composite granulating device since about 1980, and a device for treating each granulation method of fluidized bed, stirring, and rolling in the same container has been put into practical use. Was done. Composite granulation combines or fuses the functions of stirring granulation, tumbling granulation, and fluidized bed granulation in the same container to freely produce the quality of granules such as shape, density, and particle size. Function and mixing, granulation, drying,
There is a function that can be arbitrarily operated according to the purpose and purpose of unit operation such as coating.

Specific examples of various composite type granulating apparatuses include the following apparatuses. First, as the stirred fluidized bed type, there are "Super Fine Matrix SMA type" manufactured by Nara Machinery Co., Ltd. and "Multiflex Granulator MP type" manufactured by Paulex. As the rolling fluidized bed type, "Spiracoater SP type" manufactured by Okada Seiko Co., Ltd. may be mentioned. In addition, examples of the agitated rolling fluidized bed type include “Spiraflow SFC type” manufactured by Freund Sangyo Co., Ltd. and “New Malmerizer NQ type” manufactured by Fuji Paudal. Most of the fluidizing devices are of a batch type (batch processing type), and spray granulation (coating) is performed by a spray gun (spray nozzle) from the upper part or side surface of a fluid plate or stirring blade.
The processed product after the spray granulation process is discharged to the outside from the product discharge port via the discharge valve on the lower side surface.

These devices and methods are described in Japanese Patent Publication No.
-56935, Japanese Patent Publication No. 31063, Japanese Patent Publication 3-4
No. 2028, Japanese Patent Publication No. 3-42029, Japanese Patent Publication No. 3-13
No. 5430, No. 5-4128, No. 5-499
No. 01, Japanese Patent Fair 5-11508, Japanese Patent Fair 5-1925
No. 55, Japanese Examined Patent Publication No. 6-186, etc., but there is no description of atomization control on the atomized droplet diameter, and therefore, many split recoil liquids are generated when powder particles collide. Droplets are generated, and these droplets adhere to the inner wall surface of the device, the rotating blades, or other powder particles, and a lot of aggregates are generated. At the same time, the fragmented recoiled droplets are much smaller than spray droplets, so that some of them solidify instantly, and the solidified coating material is dried and solidified (coat dust) on the powder surface. It adheres and deteriorates the coat quality.

On the other hand, dipping off for the purpose of forming a smooth film on the surface of the substance to be coated has also been introduced. This method is a method of immersing a tablet pill in a coating solution in the pharmaceutical field and the like and pulling it up to dry it, but it is not suitable for coating and coating powder particles having a small particle size. In the case of a powder having a small particle diameter, the particles adhere to each other and agglomerate in the drying step after the immersion to finally become a nodule state, which is difficult in the field where the form of primary particles is required.

Further, the solvent boiling point of the coating liquid is 100.
In the case of a solvent having a temperature of ℃ or higher, the temperature in each of the granulators introduced so far is below the boiling point in many cases, so that a defective product may be produced. In particular, in a mixing granulation method in which a jacket is heated for drying, the tendency is remarkable in a mixer and the like, and the particles after coating tend to form block-like lumps.
In addition, the residual solvent gas is likely to fill the inside of the device, which causes environmental and safety problems.

On the other hand, since each of the granulation methods introduced above is a batch process (batch type), the processing time per batch is long and the productivity is poor. In addition, if the carrier particle diameter to be coated is reduced, if it is attempted to produce under the same production conditions (same carrier loading amount, same air flow amount, same film thickness, etc.), it will result in a single carrier particle. Surface area / volume amount is smaller. However, when compared with the same charge amount, both the surface area / volume amount increase, and the dry heat quantity becomes insufficient. Also,
As a single particle, compared to the particle before being reduced in particle size, the amount of fly up is large and at the same time the height of fly up is also high, and a large amount of the coated carrier is likely to be discharged to the outside of the apparatus, leading to a reduction in the recovery rate.

[0008] Therefore, if the amount of soaring is controlled (height control) for the purpose of improving the recovery rate, the amount of hot air decreases, carrier aggregates after coating frequently occur, and the amount of deposits in the layer increases. The amount collected is reduced. (In a general rolling fluidized bed, air for carrier raising and air for dry feeding are shared, so controlling the carrier raising naturally reduces the amount of hot air). Besides, in order to improve the recovery rate, many fine filters are installed in the fluidized bed exhaust part to prevent carriers discharged out of the bed, but this method also has a problem. As one of them, when it is used for a long period of time or coated with a carrier having fine particle diameter, a small-diameter carrier adheres to the filter or a large amount of resin mist adheres to cause clogging immediately. As a result, the gas concentration in the bed rises, which may force production in dangerous conditions (explosion, etc.). Further, since there is no smooth air supply / exhaust in the layer, the temperature in the layer may be lowered, and agglomeration due to poor drying may occur. Therefore, the usual rolling fluidized bed type coating device, when the carrier particle size is reduced,
It is said that it is not suitable for coating small particle size because it has some of the problems mentioned above.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic carrier manufacturing apparatus capable of coating carrier particles with high efficiency by solving the problems of the conventional electrophotographic carrier manufacturing apparatus. To do.

[0010]

According to the present invention, (1)
In a carrier manufacturing apparatus configured to coat a resin on the surface of a carrier core material with a rolling fluidized bed in a granulation cylinder,
A rotating disk plate for supplying heated air rising from below the rolling fluidized bed along the inner wall of the granulating cylinder is provided, and also prevents the rolling fluidized bed from flying up and disintegrates agglomerated particles. And a secondary air inflow pipe for forming a swirl flow in the upper part of the rolling fluidized bed and for supplying the air having a temperature higher than that of the heated air introduced through the rotating disk plate, and further Provided is an electrophotographic carrier manufacturing apparatus, characterized in that a classifying blade that disperses a resin mist and a coating carrier by rotating mechanically or pneumatically to an exhaust pipe is disposed above the center of the granular cylinder. To be done.

According to the invention, (2) the above (1)
In (1), the classification blade is capable of arbitrarily changing the number of rotations according to the particle diameter of the coating carrier, and an electrophotography having a structure in which a plurality of flat blade blades having an upward spread are fixed to the drive shaft. An apparatus for manufacturing a carrier is provided.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a rolling fluidized bed coating apparatus shown in FIG. 1, for example, is used as a coating apparatus. In these figures, 1 is a granulating cylinder, 2 is a powder fluidized bed (carrier fluidized bed), 3 is a liquid pump, 4 is a spray nozzle, 5 is a rotating disk plate, 6 is a humidity controller, 7 is a blower, and 8 is Air supply pipe, 9 exhaust pipe, 10 classification blade,
Reference numeral 11 is a classification blade drive motor, and 12 is a secondary air inflow pipe. Further, 13 is an air volume adjusting valve, and 14 is a rotary disk drive motor.

In the granulating step, carrier particles are supplied into the granulating cylinder 1, and the rotating disk plate 5 is passed through a blower 7.
A heating gas is supplied from below to form the carrier fluidized bed 2. The carrier particles are spray-coated by spraying droplets from a spray nozzle 4 located in the carrier fluidized bed 2, and the obtained granulated product (product) is collected and supplied to the next step. The coating apparatus of the present invention is
At the time of spray coating, carrier particles blown up by dry hot air are separated into coated carrier particles and resin mist while being crushed by a classifying blade 10 installed at the upper part of the apparatus and secondary air flowing through a secondary air inflow pipe. .

As shown in FIG. 5, the classification blade 10 of the present invention has a basic structure in which a plurality of flat plate blades 10a having an upward spread are fixed to a drive shaft. In order to fix the plurality of flat plate blades 10a to the drive shaft 10b, as shown in FIG. 4, a plurality of flat plate blade fixing grooves are provided radially, and a small ring provided with a hole for passing the drive shaft 10b in the center thereof. A circular disk 10c and a large ring-shaped disk 10d having a plurality of similar flat blade fixing grooves radially and having a hollow central portion, and the central hole of the small ring-shaped disk 10c is prepared. Inserted into the drive shaft 10b, the upper and lower ends of the flat blade 10a are a large ring-shaped disc 10d and a small ring-shaped disc 10c.
It is made by fitting it into each of the fixing grooves, and then fitting the conical screw 10e into the lower end of the drive shaft 10b.

The classification blade 10 is rotated by a drive motor 11 or an air motor, but the rotation speed can be arbitrarily changed depending on the carrier particle diameter. When the carrier particle diameter is large, the carrier particles and the resin mist are sufficiently separated even at a relatively low rotation, but when the carrier particles are reduced in particle size, it is necessary to increase the rotation speed of the classification blade 10. However, since the difference in specific gravity between the carrier particles and the resin mist is large, it is not necessary to make the rotation extremely high. When the classifying blade 10 rotates at high speed, the carrier particles are classified into the classifying blade 1.
Since it is crushed by the impact of 0, it is necessary to avoid classification in the high speed range.

The rolling fluidized bed coating apparatus of the present invention comprises:
Secondary air inlet 12 that provides the effect of suppressing soot particles and the effect of dispersing aggregated carrier particles on the upper side of the device.
a, and a secondary air gas having the same temperature or higher as the heating gas supplied from below the rotating disk plate 5 flows in from the inflow port 12a in the apparatus. As shown in FIG.
The next air gas forms a swirling flow around the granulation cylinder in the upper part of the fluidized bed, and suppresses the carrier particles and resin mist rising and rising after coating to the lower part of the fluidized bed. Further, at the same time, the coated carrier that has aggregated and floated up is crushed, so that only the resin mist is classified with higher accuracy and then discharged to the outside of the layer. FIG. 3 shows the rotating disk plate 5 and the mesh 15.
It represents the positional relationship with.

The rolling fluidized bed coating apparatus of the present invention comprises:
Since the product component (coated carrier) discharged to the outside by the rotation of the classification blade and the secondary air is suppressed as much as possible, the product recovery rate becomes very high. On the other hand, a band-shaped carrier fluidized bed is formed on the lower side of the fluidized bed due to the secondary air inflow effect. At this time, since the spray nozzle 4 is spray-coated in the belt-shaped swirling fluidized bed of the carrier, the carrier particles are efficiently spray-coated. Therefore, the adhesion efficiency of the coat resin is increased, and at the same time, since the amount of the sprayed particles other than the carrier particles (inner wall surface, etc.) is small, the adhesion and adhesion to the inner wall surface are reduced.

In the classifying blade of the present invention, the number of rotations of the blade varies depending on the carrier particle diameter.
Used at 0 rpm range. Rotation speed is 200r
When the classification treatment is performed in the rotation range of pm or less, the cut point shifts to the large particle size side, and thus the coated carrier particles are easily discharged out of the layer together with the resin mist. Moreover, when the rotation speed is classified at a rotation speed of 1000 rpm or more,
The cut point shifts to the small particle size side and the resin mist is accurately removed to the outside of the layer, but on the other hand, when the coated carrier particles collide with the classification blade, they are crushed by the impact of the blade rotation and the carrier particle size at the time of loading Also becomes a small particle size carrier. In addition, a part of the miniaturized carrier is exhausted to the outside of the layer, and the product recovery rate also decreases.

The secondary air in the present invention is performed by the inflow of a heating air gas having a temperature equal to or higher than that of the dry heating gas supplied from the lower part of the apparatus. When the temperature of the secondary air is lower than the temperature of the heating gas supplied from below, the atmospheric temperature in the layer is lowered, the coated film after coating is difficult to dry, and the agglomerates of the coated carrier increase.

The installation position of the spray nozzle 4 of the present invention is
The carrier particle layer 2 is installed at the inner peripheral portion to the central portion of the flowing carrier particle layer 2. When the installation position is further inside the innermost part of the particle,
Split recoil droplets that are generated when spray droplets collide with carrier particles adhere to the disk plate, are dried and become resin particles (mist) and are exhausted to the exhaust side, or adhere to the surface of the coated carrier particles, resulting in quality characteristics. Problems that affect the. On the other hand, if the installation position is outside the center, there arises a problem that it penetrates the carrier fluidized bed and adheres to the inner wall of the apparatus, causing carrier particles to adhere to the inner wall.

[0021]

EXAMPLES Next, the present invention will be described more specifically by way of examples. The fixing conditions in each example are as follows. [1] Coating device: Spirako-Tar SP-40 manufactured by Okada Seiko Co., Ltd. [2] Coating liquid used: 20% silicone resin solution (solvent is a mixed solvent of 70 parts by weight of toluene and 10 parts by weight of methanol). (Toray Co., Ltd .: SR-2411) [3] Carrier particles: Ferrite carrier having an average particle size of 50 to 100 μm [4] Processing amount: 5 kg / batch (once / batch)

Examples 1 to 6 and Comparative Examples 1 to 5 Tests were conducted under the conditions shown in Table 1, and the results are shown in the same Table 1.

[0023]

[Table 1]

The evaluation with respect to Table 1 was carried out as follows. 1: Product recovery rate is the recovery weight ratio after coating (wt%) with respect to the total input amount. However, the agglomerated powders were excluded from the volume after coating. (Because agglomerated products cannot be used as products) 2: The degree of agglomeration is defined as the total amount of the carrier particles before the input coating and the resin solid content after the coating liquid after spraying is the total input amount, based on the weight. The weight ratio remaining above the reference mesh is divided into 5 ranks, and the good ones are [◎] and the bad ones are [x]. 3: [Coating material residue generation degree] is that the particle surface after coating is observed with an electron micrograph, and the degree is divided into 5 levels, [◎] having almost no residue and “x” for some. Then, the ranking was performed in the same manner as in the evaluation of adhesion on the inner wall surface. 4: Regarding the charging characteristics, the deviation degree with respect to the reference value (target value) was classified into 5 levels, with a small deviation being [⊚], and a large deviation being “x”, and evaluated according to the deviation degree. 5: For the electrical characteristic [resistance value], a value obtained by converting the static resistance value due to the parallel electrodes into the volume resistivity is calculated and is a reference value (target value).
The degree of misalignment was classified into 5 levels, the one with less misalignment was [⊚], the one with more misalignment was “x”, and the evaluation was classified according to the misalignment degree. 6: Comprehensive evaluation was classified into 5 grades, with [Excellent] as the overall superiority, including product productivity and quality of the product, and “Poor” as not.

[0025]

According to the apparatus for manufacturing an electrophotographic carrier of the present invention, the coated product carrier can be prevented from being discharged out of the layer, so that the product recovery rate can be improved, the productivity can be improved, and the cost can be reduced. Since the adhesion to the inner wall of the coating device can be reduced, maintenance is facilitated. Since the aggregation of particles during coating and drying is reduced, the quality characteristic values are stable and the yield is also improved. It is possible to achieve high-performance coating, and it is possible to obtain high-quality products.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an example of a rolling fluidized bed coating apparatus used in the present invention.

FIG. 2 is a schematic diagram showing a carrier flow state in the present invention.

FIG. 3 is a perspective view showing a positional relationship between a fixed disk plate and a mesh.

FIG. 4 is a schematic explanatory view of a classification blade of the present invention.

FIG. 5 is a perspective view of a flat blade.

[Explanation of symbols]

 1 Granulation Tube 2 Powder Fluidized Bed 3 Liquid Pump 4 Spray Nozzle 5 Rotating Disc Plate 6 Humidity Controller 7 Blower 8 Air Supply Pipe 9 Exhaust Pipe 10 Classification Blade Main Body 11 Classification Blade Drive Motor 12 Secondary Air Inflow Pipe (12a, Secondary air inlet) 13 Airflow adjustment valve 14 Rotating disk drive motor 15 Mesh

Claims (2)

[Claims] 1. A carrier manufacturing apparatus in which a surface of a carrier core material is coated with a resin by a rolling fluidized bed in a granulating cylinder, and the resin is coated from below the rolling fluidized bed along the inner wall of the granulating cylinder. A rotating disk plate for supplying ascending heated air is provided, and the rising of the rolling fluidized bed is prevented and the agglomerated particles are crushed to form a swirling flow above the rolling fluidized bed. A secondary air inflow pipe for supplying air having a temperature higher than that of the heated air introduced through the rotating disk plate is provided, and further, a mechanical force or an aerodynamic force is provided above the central portion of the granulation cylinder to the exhaust pipe. An electrophotographic carrier manufacturing apparatus, characterized in that a classification blade for rotating and dispersing the resin mist and the coating carrier is provided. 2. The classifying blade is capable of arbitrarily changing the number of revolutions according to the particle diameter of the coating carrier, and has a structure in which a plurality of flat blade blades having an upward spread are fixed to a drive shaft. The electrophotographic carrier manufacturing apparatus according to claim 1.