JP2003088770A - Grinder and method for producing toner by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grinder that can easily produce fine crushed product of the order of several micrometers for a long term, to provide a method for producing a toner by using the grinder, and to provide a method for forming an image by using the toner. SOLUTION: In a grinder which is provided with a rotor supported by a rotary shaft and having many irregularities being parallel with the generator and consecutively in the peripheral direction on the external periphery and a cylinder fitted into the outside of the rotor so as to leave a small clearance between them and having many irregularities being parallel with the generator and consecutively in the peripheral direction on the internal periphery and pulverizes the thing to be ground in a grinding chamber comprising the small clearance, a discharge flow passage 7a for the pulverized product is formed near the charge flow path for the thing to be pulverized; an entering flow passage 8a for the thing to be ground is formed near the flow passage 7a; and a changing or selecting means 11a to 11d that arbitrarily change or select the flow passage according to the accumulation of the time of grinding are formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for finely pulverizing an object to be pulverized having a particle size of micron order into fine particles of tens of micron order, and particularly to a machine suitable for producing a toner used in an image forming apparatus. Type crusher.

[0002]

2. Description of the Related Art In recent years, in image forming apparatuses aiming for high image quality, digitization and colorization have progressed, and dry toner used has a smaller particle size, improves copy speed and is environmentally friendly. Therefore, a toner capable of fixing at a lower temperature has been demanded. As a technique for producing such a toner, conventionally, a technique of pulverizing a toner by a pulverizing device, particularly a rotary mechanical pulverizing device is known, and specifically, JP-A-59-105853,
JP-A-8-71439, JP-A-7-92733, JP-A-8-299827, and JP-B-3-15
489, JP-A-5-269393, JP-A-7-155628, JP-B-61-36457, JP-B-58-14822, and JP-B-58-14.
There are technical disclosures related to Japanese Patent Publication No. 823, Japanese Patent Publication No. 61-36459, Japanese Patent Publication No. 4-12191, Japanese Unexamined Patent Publication No. 5-184960, Japanese Patent Publication No. 4-12190.

Among them, the rotary type mechanical crushing device described in Japanese Patent Application Laid-Open No. 59-105853 (see also Japanese Patent Publication No. 3-15489) is a sectional view of FIG.
As shown in FIG. 2 which is a side view of AA ′ in FIG. 1 and FIG. 3 which is a side view of BB ′ in FIG. A cylindrical rotor 2 having a concavo-convex portion 1 continuous in the circumferential direction is supported by a rotating shaft 3, and a minute gap 4 is formed outside the rotor 2, and a large number of concavo-convex portions parallel to the generatrix are formed on the inner peripheral surface. A cylindrical stator (cylindrical body) 6 in which the portion 5 is continuous in the circumferential direction is fitted and the gap 4 serves as a crushing chamber. Explaining the crushing process by this fine crusher, the rotor 2 is rotated at high speed and the stator 6
The suction blower (not shown) connected to the product discharge port 7 provided above is operated to supply the crushed material to the inside of the machine through the supply port 8 provided below the stator 6 along with air. Inside the machine, the object to be crushed has an outer peripheral unevenness 1 that rotates integrally with the rotor 2.
Rises along the inner peripheral surface of the crushing chamber, flows into the crushing chamber 4 which is a facing gap between the rotor 2 and the stator 6, and rides on the upward swirling airflow generated by the rotation of the rotor 2. The crushing is performed while flowing through the facing gap 4 in the upward flow. That is, the crushed object is given kinetic energy by the rotor 2 rotating at a high speed, rides on the vortex generated in the uneven portion 5 of the stator 6 and collides with the uneven portion 5,
Fine particles are produced by being ground between the convex portions of the rotor 2 and the stator 6, and flow out from the gap 4. The fine particles swirl up along the inner peripheral surface of the casing 10 by the air flow generated by the outer peripheral irregularities 1 rotating integrally with the rotor 2, and are discharged from the product discharge port 7 to the outside of the machine. In this way, the object to be crushed has its uneven surface and the stator 6 by the high speed rotation of the rotor 2 in the crushing chamber formed by the gap 4 between the rotor 2 and the stator 6.
Collide with each other due to the vortex flow generated from the uneven surface and are subjected to shearing force to be finely pulverized into fine particles of tens of microns to several microns order.

[0004]

However, if the above-mentioned requirements are met by the conventional crushing apparatus, Due to friction, collision energy, etc., the crushed object is fused and fixed in the crusher, and the production capacity (crushing capacity) is reduced. 2. Increase of grinding frictional heat due to decrease of grinding ability (grinding Δt
Due to (increased temperature by 0 ° C.), low molecular weight and Wax components in the composition of the object to be pulverized are deposited to deteriorate the toner quality. 3. Due to environmental fluctuations (humidity), the material to be ground in the grinding machine sticks and reduces the grinding capacity. Toner image quality (background stain, fixing failure, white spot, image density, etc.) is deteriorated due to 4.1 to 3. However, there were problems such as problems such as stable production and insufficient crushing in terms of quality. The present invention is intended to solve the above problems, and provides a crushing device that can easily obtain a fine pulverized product of the order of several microns over a long period of time, a toner manufacturing method using the device, and an image forming method using the toner. The purpose is to provide.

[0005]

In order to achieve the above object, the invention according to claim 1 is a rotation in which a large number of concavo-convex portions which are supported by a rotating shaft and which are parallel to a generatrix are continuously formed on the outer peripheral surface in the circumferential direction. The rotor, and a cylindrical body fitted on the outer side of the rotor with a minute gap and having a large number of concavo-convex portions parallel to the generatrix continuously formed on the inner peripheral surface in the circumferential direction. In a pulverizer that pulverizes finely in a pulverization chamber consisting of a gap, a discharge passage for finely pulverized products is provided on the supply side of the pulverized products, and an inflow passage for pulverized products is provided on the discharge side of the finely pulverized products. The most main feature is a crushing device provided with a changing or switching means for arbitrarily changing or switching the flow path based on the above. The invention according to claim 2 is the crushing device according to claim 1,
When changing and using the flow path for sucking the object to be crushed and the flow path for crushing by the rotor to become fine powder and exhausting it, the crushing device is provided with a means for rotating the rotary cylinder once in the reverse rotation and then in the forward rotation. Is the main feature. A third aspect of the invention is characterized mainly in the crushing apparatus according to the first or second aspect, in which the crushed object staying in the machine has a time of 0.001 to 1.0 sec. According to a fourth aspect of the present invention, in the crushing apparatus according to any one of the first to third aspects, the difference between the inlet temperature of the machine to which the object to be crushed is supplied and the temperature of the crushed product discharged after crushing in the machine is 10 to 60 ° C. The main feature is a grinding device. A fifth aspect of the present invention is characterized in that, in the crushing device according to any one of the first to fourth aspects, the crushing device has an internal humidity during crushing of 0 to 50% or less. A sixth aspect of the present invention is characterized in that the toner manufactured by using the crushing device according to any one of the first to fifth aspects is the most main feature.
The invention described in claim 7 is characterized by a toner manufacturing method of crushing a toner using the crushing device according to any one of claims 1 to 5. The invention according to claim 8 is
An image forming apparatus using the toner manufactured by using the crushing apparatus according to any one of claims 1 to 5 is the most main feature.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 4 is a sectional view of the mechanical crushing device of the present invention. 5 is a side view from CC ′ of FIG. 4, and FIG. 6 is a side view from DD ′. As shown in these figures, compared to the conventional example shown in FIGS. 1, 2 and 3, a new crushed material inflow path 8a and a new crushed material discharge path 7a are installed. As is clear from FIG. 4, the inflow passage 8a and the exhaust passage 7a are installed on the side of the exhaust passage 7 and the inflow passage 8 shown in FIG. 1, respectively. In addition, referring also to FIG. 1, the same portions are denoted by the same reference numerals for description. In the conventional example, the inflow and outflow of the crushed object was a unidirectional flow as shown in FIG. 7, but in the example of the present invention, as shown in FIGS. 8 and 9, a switching valve (switching means) 11 (general (The valve used in (1) is used) is arranged, and the opening / closing switching operation of the valve 11 is performed according to the grinding operation time. For example, when forming a conventional powder flow, the suction flow path 1 shown in FIG.
1a is open, 11b is closed, exhaust flow path is open 11c, 11b
When the flow of powder is to be reversed, the suction flow passage 11a shown in FIG. 8 is closed, 11b is opened, and the exhaust flow passage is closed by 11c and 11b is opened so that the flow can be freely changed. Valve 1
By switching the opening and closing of 1, the flow direction of the powder can be arbitrarily changed or switched by the crushing processing accumulated time, so that the crushed material adhered and accumulated on the uneven surface is peeled off.
The initially set crushing condition can be maintained for a long period of time even when crushing a material such as a low temperature fixing toner that is likely to cause fusion and sticking of a crushed object.

[0007]

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to the following examples. Example 1 A mixture of 75% by weight of polyester resin, 10% by weight of styrene-acrylic copolymer resin and 15% by weight of carbon black was melt-kneaded by a roll mill, cooled and solidified, and then coarsely pulverized by a hammer mill. Next, using the mechanical crusher shown in FIG. 4 and using the crushing flow shown in FIG. 9, the clearance 4 of the rotor 2 is set to 1.5 mm, and the peripheral speed of the rotor is 14 mm.
When set to 0 m / s and crushed for 500 hours, valve switching operation 11a → 11b, 11c → 11d shown in FIG. 8 was performed and further crushed for 500 hours to obtain a weight average particle diameter of 9.3 μm and
The number content of ultrafine particles of μm or less was 32%. A Coulter Counter Multisizer was used to measure the particle size. (Comparative Example 1) Particles equivalent to those of Example 1 could be obtained after crushing for 500 hours under the same crushing conditions as in Claim 1 with the conventional crushing apparatus shown in FIG. 1, but the weight average particle diameter was 9 after 550 hours. The number content of ultrafine particles of 8 μm or 4 μm or less was 30%. Example 2 Example 1 as described in the present invention
After crushing for 500 hours using the flow shown in FIG. 9 under the conditions shown in FIG. 9, the apparatus was temporarily stopped, and after reversely rotating at a peripheral speed of 100 m / s for 5 minutes, the valve operation shown in FIG. 8 was performed and the 650 hr weight average particle diameter was changed to 9. The number content of ultrafine particles of 4 μm or less at 2 μm was 31%. A Coulter Counter Multisizer was used to measure the particle size.

(Embodiment 3) In order to satisfy the conditions described in the present invention, the flow time of the object to be ground in the machine is 0.07 sec. The air volume of the suction blower is adjusted so as to be equal to, and after crushing for 500 hours, the flow is changed to that of FIG.
Then, the number content of ultrafine particles of 4 μm or less was 33%.
A Coulter Counter Multisizer was used to measure the particle size. The passing time inside the crusher is calculated by the following formula. Transit time (S) = (grinding internal volume _{(d 1/2) ^ 2} * π
^{(M 3)} - rotor volume _{(d 2/2) ^ 2} * π (m 3))
/ Suction blower air flow rate (m ³ / min) (Example 4) A mechanical crushing apparatus that satisfies the conditions described in the present invention, and the inside of the apparatus when crushing the object to be crushed using the flow of FIG. 9 under the conditions shown in Example 1. Adjust the temperature of the inflowing air stream so that the humidity is 20%, pulverize for 500 hours, and then change to the flow in FIG.
Further, the ultrafine particles having a weight average particle diameter of 500 hr of 8.9 μm and 4 μm or less were 34% in number content ratio. A Coulter Counter Multisizer was used to measure the particle size.

[0009]

According to the first to fifth aspects of the present invention, the mechanical crushing apparatus can maintain a high production condition for a long period of time as compared with the conventional apparatus and can easily obtain a fine crushed material. it can. According to the invention of claim 6 or 7, it is possible to easily obtain a toner quality in which the crushed particle size distribution is constant, coarse particles do not jump in, and the crushed particle shape and the both are uniform.
According to the invention described in claim 8, it is possible to form an image without deterioration of toner image quality (background stain, fixing failure, white spot, image density, etc.).

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a conventional crushing device.

FIG. 2 is a side view from AA ′ of a conventional crushing device.

FIG. 3 is a side view from the BB ′ of the conventional crushing device.

FIG. 4 is a sectional view of the crushing device of the present invention.

FIG. 5 is a side view from CC ′ of FIG. 1, which is the crushing apparatus of the present invention.

FIG. 6 is a side view from DD ′ in FIG. 1, which is the crushing device of the present invention.

FIG. 7 is an explanatory diagram showing a flow of powder in a conventional crushing device.

FIG. 8 is an explanatory diagram of the flow of powder from the inflow passage 8a and opening / closing of the valve of the crushing device of the present invention.

FIG. 9 is an explanatory view of the flow of powder from the inflow passage 8 and opening / closing of the valve of the crushing device of the present invention.

[Explanation of symbols]

2 rotors, 3 rotation shafts, 4 gaps (grinding chamber), 5 inner peripheral surface irregularities, 6 stators, 7 outlets, 7a outlet channels, 8 inlets, 8a inlets, 11a, 11b Switching valve, 11c, 11d Ground material discharge switching valve

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Claims (8)

[Claims] 1. A rotor, which is supported by a rotary shaft and has a large number of concavo-convex portions formed continuously on the outer peripheral surface in parallel to the generatrix, and an inner periphery which is fitted on the outer side of the rotor with a minute gap. In a crushing device that is provided with a cylindrical body in which a large number of concavo-convex portions parallel to the generatrix are continuously formed in the circumferential direction on the surface, and the crushing object is finely crushed in a crushing chamber having the minute gap, A change or switching means for providing a discharge passage for finely pulverized products near the passage and an inflow passage for crushed products near the discharge passage for finely pulverized products to arbitrarily change or switch the passages based on the accumulated processing time of pulverization. A crushing device characterized by being provided with. 2. The crushing apparatus according to claim 1, wherein when the flow path for sucking the crushed object and the flow path for crushing by the rotor and discharging as fine powder are changed and used, the rotor is temporarily reversed. A crushing device, characterized in that it is provided with means for normal rotation after rotation. 3. The crushing apparatus according to claim 1 or 2, wherein the time of the material to be ground remaining in the machine is 0.001 to 1.0 s.
A crushing device characterized by being ec. 4. The crushing apparatus according to claim 1, wherein the temperature difference between the inlet temperature of the machine to which the material to be crushed is supplied and the temperature of the material discharged after crushing in the machine is 10 to 60 ° C. Crushing device. 5. The crushing device according to claim 1, wherein the internal humidity during crushing is 0 to 50% or less. 6. A toner produced by using the crushing device according to claim 1. 7. A toner manufacturing method for crushing a toner using the crushing device according to claim 1. 8. An image forming apparatus using a toner produced by using the crushing apparatus according to claim 1.