JP2003084496A - Continuous type crushing method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a continuous type crushing method and device without fusing crushed toner and degrading quality even when an operation is continuously performed for a long period of time. SOLUTION: For the continuous type crushing method and device, in the crushing method of forming toner coarse particles, the toner to be crushed is periodically supplied with a low amount or an increased amount as a cycle and a supply amount in an increased amount cycle in it is increased/decreased in relation to a volume average particle diameter of the toner coarse particles to be formed. Especially, when the volume average particle diameter of the toner coarse particles is 40 μm or less, it is preferable to increase the supply amount in the increased amount cycle compared to crushing throughput.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous crushing method and apparatus for electrostatic charge developing toners, and more particularly, to an electrostatic charge developing toner suitable as a method for producing a toner having a low softness and a small particle size. And a continuous crushing method and apparatus improved so as to enable crushing of a uniform particle size distribution.

[0002]

2. Description of the Related Art Conventionally, a crushing method for producing coarse toner particles is carried out by a so-called batch method in which the amount of crushed material is the same as the amount of crushed material supplied. However, the batch method has extremely low productivity in that the amount that can be processed by one crushing is limited. Further, in order to improve productivity, it is necessary to repeat the experiment to find the amount that can be crushed at one time, that is, the condition that the particles do not melt due to heat generation, and it took time to find the optimal amount.

In the case of crushing by the batch method, the crushed toner is softened by heat generation and the following phenomenon is observed. That is, the toner pulverized by continuous operation for a long time is melted, which causes a serious problem in quality. However,
This problem can be avoided by reducing the feed rate which is crushed at once before melting. However, when the supply amount of the pulverized toner is suddenly reduced, the crushed particle size varies with time. That is, in the first half of continuous operation for a long time after the start of crushing, the proportion of toner for fine powder tends to be high and the proportion of toner for coarse powder tends to be low. On the other hand, it is well known from experience that the proportion of toner of fine powder is small and the proportion of toner of coarse powder is large in the latter half of continuous operation for a long time.

Therefore, in the case of continuous operation, the particle size distribution to be fed to the next step (crushing / classifying device) varies with the passage of time, and a feed variation occurs, which causes a serious quality problem. Naturally, a continuous pulverizing method, which is far more productive than the batch method, has been studied, but there is still not enough one. In particular, a sufficient crushing method has not been found for a toner containing an inorganic pigment that is difficult to pulverize.

[0005]

SUMMARY OF THE INVENTION The present invention provides a continuous crushing method and apparatus in which the crushed toner is not melted and the quality is not deteriorated even if it is continuously operated for a long time. The present invention provides a continuous pulverization method that is much more productive than the batch method, as well as suppressing toner melting.

[0006]

The present invention has a problem in the continuous crushing method that there is a phenomenon that the target coarse particles of the toner are different above and below a certain volume average particle diameter (40 μm). As a result, the present invention was completed. That is, the present invention has the following configurations. (1) In the crushing method for producing coarse toner particles, the supply of the crushed material toner is not performed periodically as a cycle of decreasing or increasing the amount, and the supply amount of the increasing cycle is
A continuous crushing method characterized by increasing / decreasing the volume of toner coarse particles to be built up in relation to the volume average particle diameter.

(2) The continuous crushing method described in (1) above, wherein when the toner coarse particles having a volume average particle diameter of 40 μm or less are prepared, the amount of supply in the increasing cycle is larger than the crushing capacity.

(3) In the case where coarse toner particles having a volume average particle size of 40 μm or more are prepared, the supply amount in the increasing cycle is smaller than the crushing capacity, and continuous crushing according to the above (1). Method.

(4) The continuous crushing method according to any one of (1) to (3) above, wherein the toner to be crushed is intermittently supplied.

(5) The continuous crushing method according to any one of (1) to (4) above, wherein when the residual toner in the crusher is exhausted, the toner to be crushed is supplied.

(6) The continuous crushing method according to any one of (1) to (5) above, wherein the amount of toner to be crushed supplied to the toner is controlled by a twin timer.

(7) The toner to be crushed is supplied by using a screw feeder, and the supply amount of the toner to be crushed is controlled by changing the number of revolutions of the screw feeder. The continuous crushing method described.

(8) A continuous crushing device characterized in that a crushing chamber provided with a feeder for the toner to be crushed is provided with an uneven liner, and a flat plate hammer rotating at a portion facing the liner is provided. .

(9) One side of the liner projection is perpendicular to the liner surface, and the included angle α between the one side and the other side (other side) of the liner projection is 30 to 75 degrees. ) The continuous crushing device described.

(10) The continuous crushing device as described in (8) or (9) above, wherein the flat plate hammer has a sharp shape.

(11) The continuous crushing device according to any one of (8) to (10), wherein the tip of the flat plate hammer that collides with the crushed object is lined with a wear resistant material.

(12) The continuous crushing device according to any one of (8) to (11), wherein the liner provided inside the casing is removable.

(13) A thin plate (skimmer cage) is provided in the gap between the liner provided inside the casing and the casing so that the gap between the hammer and the liner can be set arbitrarily. The continuous crushing device according to any one of 1.

(14) The above (8) to (1), wherein a cooling jacket is provided on the casing side having the liner.
The continuous crushing device according to any one of 3).

That is, in the present invention, by devising the method of supplying the toner to be crushed, the melting of the toner due to the heat generated at the time of crushing is eliminated and the dispersion of the particle size distribution in the next step (crushing and classifying step) is prevented. be able to. In particular, the configuration (2) has a remarkable effect, and enables stable treatment even if the crushed material has an excessively long residence time. On the contrary, in the case of the above (3), stable treatment is possible even if the treatment residence time is somewhat short.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments suitable for producing a dry toner for developing electrostatic charges in electrophotography, electrostatic recording, electrostatic printing, etc. will be described below with reference to the drawings.

FIG. 1 shows a cycle method of the first crushing method of the present invention. That is, a model of the crushed object supply screw rated current is shown, and B in FIG. 1 is the rated load current when the conventional continuous supply is performed. In the present invention, it means a supply system in which a supply cycle is provided between the I and H. By the way, a indicates that the supply is larger than the rated load current (max + 23% or less of the motor rated current value), and c is supplied (rated load current min + 10% or more) in a region where supply is not stopped.

As a supply principle, in the area between I and H, the supply is periodically performed with a low amount or an increased amount as a cycle. In this method, by adjusting the amount of the toner to be crushed during the increase cycle, it is possible to eliminate the toner melt due to the heat generated during the crushing, and it is possible to prevent the variation in the particle size distribution. Regarding the supply current value, max + 23% or less of the motor rated current value may occur, and there is concern that toner may melt due to heat generation. However, by setting the supply cycle, the surface temperature of the crushed object is 58 ° C for the same amount of supply. Melting occurred due to the above, but 43
It became possible to suppress the temperature to below ℃.

FIG. 2 shows an intermittent method which is the second crushing method of the present invention. In the figure, “a” has the same meaning as in FIG. 1, but the principle of supply is that the “b” region is used for supply operation (ON) and the “2” region is used for intermittent supply by stopping supply (OFF). By this method, the melting of the toner due to the heat generated at the time of crushing can be eliminated, and the dispersion of the particle size distribution can be prevented. Specifically, depending on the relationship between the amount of toner remaining in the crusher and the hammer load, the supply of crushed toner is turned off,
It is possible to freely adjust ON.

FIG. 3 is a graph showing the relationship between the residual toner amount inside the crusher and the hammer load. As is clear from this graph, the hammer load is reduced as the residual toner inside the crusher decreases. Similarly, when the residual toner amount is large, the hammer load current value becomes high.

FIG. 4 shows one of the supply principles to which the above relationship is applied. That is, the supply operation (ON) is started after the hammer load current value is detected in the idle operation, and the supply is stopped (OF) after the hammer load current value is detected to be less than max + 10%.
F) shows the principle of intermittent supply. By this method, it is possible to eliminate the melt of the toner due to the heat generated at the time of crushing, and it is possible to prevent the dispersion of the particle size distribution. Twin timer is used for intermittent supply. The twin timer is a timer having a function of turning on and off periodically by setting conditions (temperature, time, etc.) in advance.

As shown in FIG. 4, if the intermittent supply can be ON-OFF controlled by a twin timer, the load current value during idle operation and the hammer load current value are stable without being limited after detection of the max value. Supply operation can be secured. By this method, the melting of the toner due to the heat generated during the crushing can be eliminated, and the variation in the particle size distribution can be prevented. Then, the screw feeder is used as the supply system, and the fixed amount can be supplied by changing the rotation speed.

A crushing apparatus embodying the crushing method of the present invention will be described below. FIG. 5 shows an example of a crusher equipped with a liner m and a flat plate hammer k. As shown in FIG. 5, the toner e to be crushed, which is put into the hopper f, is conveyed to the crushing chamber i by the feeder h having the supply motor g as a drive source. The crushing chamber i is provided with a flat plate hammer k capable of high-speed rotation driven by a hammer rotation motor j, and the conveyed crushed material toner e
Is crushed by the flat plate hammer k and the liner m installed in the casing l provided above the plate hammer k. The crushed toner is sorted by the mesh n provided in the lower part of the crushing chamber i, but the coarse particles that cannot pass through are pulverized by the crushing action.

FIG. 6 shows a sectional view of the flat plate hammer k. By sharpening the tip shape of the flat plate hammer k (where it collides with the object to be crushed), the crushing efficiency is improved, and the ratio of coarse particles is drastically reduced. Flat plate hammer k
When the tip of the is lined or heat treated by overcoating with a wear resistant material of stellite type or SKH type, it is 3.8 compared with the conventional SUS type material.
Double durability can be achieved.

In FIG. 7, the concave portion of the liner m is oriented in the tangential direction of the hammer k so as to face the hammer k rotating on the other side, and the toner is melted and crushed at the included angle α between one side of the concave portion and the other side. It shows the result of examining the efficiency. As a result, when the included angle α is 45 degrees, the toner temperature due to the temperature increase is 50 degrees or less, and there is no problem due to the generation of melt, and when the included angle α is 25 degrees, the melt due to heat generation occurs. When the included angle α was 80 degrees, the temperature increase was lower than when the included angle α was 45 degrees, but the crushing efficiency was reduced.
From the above results, the included angle α between a part of the recess and the other side is 30 to
It has been found that a liner recess configuration of 75 degrees is preferred.

Further, the recess of the liner m can be made removable. If the concave portion of the liner m is removable, the switching time at the time of cleaning can be shortened, and by replacing the liner m at the time of temperature rise, it is possible to provide a crushed product of good quality. Further, if a thin plate (skimmer gauge) is provided in the gap between the detachable liner m and the casing l and the gap between the hammer k and the liner m can be set arbitrarily, by adjusting this gap, In addition to the function of controlling the temperature rise, the crushed particle size can be adjusted.

FIG. 8 shows the case where a cooling jacket is installed in the casing 1. If a cooling jacket is installed on the side of the casing 1 equipped with the liner m as shown in FIG. 8, in addition to the function of suppressing the temperature rise, the crusher can be operated continuously for a longer time.

The melt to be crushed in the embodiment of the present invention and the crushable material used for measuring the particle size distribution are generally used toner materials as shown below.

Toner to be crushed: (1) Styrene-acrylic copolymer 100 parts by weight (2) Carbon black 10 parts by weight (3) Polypropylene 5 parts by weight (4) Zinc salicylate 2 parts by weight

[0035]

According to the present invention, the melting of the toner due to the heat generated during the crushing can be eliminated, the variation in the particle size distribution can be prevented, and the productivity for obtaining a high quality crushed product can be improved. High crushing processing is possible. In addition, the processing capacity can be improved even with a small machine with a small crushing capacity, and space can be reduced.

[Brief description of drawings]

FIG. 1 shows the principle of a first crushable object supply system (cycle system) in the present invention.

FIG. 2 shows the principle of a second crushable object supply method (intermittent method) in the present invention.

FIG. 3 shows the relationship between the amount of residual toner inside the crusher and the hammer load current in the present invention.

FIG. 4 shows the principle of intermittent supply of a crushed object using a twin timer according to the present invention.

FIG. 5 shows a crusher equipped with a liner and a hammer according to the present invention.

FIG. 6 is a sectional view of a hammer according to the present invention.

FIG. 7 is a sectional view of a liner according to the present invention.

FIG. 8 is a view showing an example of a casing portion provided with a coolant jacket according to the present invention.

[Explanation of symbols]

e Shatterable toner f hopper g Supply motor h feeder i Crushing room j Hammer rotation motor k hammer l casing m liner

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H005 AB04 EA05 EA07                 4D065 AA04 BB04 BB11 EB14 EB20                       EC01 ED03 ED16 ED23 ED31                       EE01 EE13 EE15 EE18

Claims (14)

[Claims] 1. A crushing method for producing coarse toner particles, wherein the supply of the toner to be crushed is not carried out on a regular basis with a cycle of reducing or increasing, and the supply amount of the increasing cycle is the amount of coarse toner to be produced. A continuous crushing method characterized by increasing / decreasing the volume in relation to the volume average particle diameter. 2. The continuous crushing method according to claim 1, wherein when the coarse toner particles having a volume average particle diameter of 40 μm or less are prepared, the supply amount in the increasing cycle is set to be larger than the crushing capacity. 3. The continuous crushing method according to claim 1, wherein when the coarse toner particles having a volume average particle size of 40 μm or more are prepared, the amount of supply in the increasing cycle is smaller than the crushing capacity. 4. The continuous crushing method according to claim 1, wherein the toner to be crushed is intermittently supplied. 5. The continuous crushing method according to claim 1, wherein the toner to be crushed is supplied when the residual toner in the crusher is exhausted. 6. The continuous crushing method according to claim 1, wherein the amount of toner to be crushed supplied to the toner is controlled by a twin timer. 7. The continuous system according to claim 1, wherein the toner to be crushed is supplied using a screw feeder, and the supply amount of the toner to be crushed is controlled by changing the number of revolutions thereof. Crushing method. 8. A continuous crushing apparatus comprising a casing of a crushing chamber equipped with a feeder for the toner to be crushed, an uneven liner, and a flat plate hammer rotating at a portion facing the liner. 9. The continuous crushing according to claim 8, wherein one side of the liner protrusion is perpendicular to the liner surface, and the included angle α between the one side and the other side of the liner protrusion is 30 to 75 degrees. apparatus. 10. The continuous crushing device according to claim 8, wherein the flat plate hammer has a sharp shape. 11. The flat hammer end, which collides with the crushed object, is lined with a wear resistant material.
11. The continuous crushing device according to any one of 1 to 10. 12. The continuous crushing device according to claim 8, wherein the liner provided inside the casing is removable. 13. A thin plate (skimmer cage) is provided in a gap between the casing and a liner provided inside the casing,
13. The continuous crushing device according to claim 8, wherein a gap between the hammer and the liner can be set arbitrarily. 14. The continuous crushing device according to claim 8, wherein a cooling jacket is provided on the side of the casing provided with the liner.