JP5304627B2 - Bead mill - Google Patents

Description

  The present invention relates to a bead mill for kneading printing ink and paint by pressure such as collision in a bead-shaped dispersion medium.

  The bead mill is known as an apparatus for continuously kneading various inks and paints in large quantities. Since this bead mill is a device that continuously operates for a long time, a load is applied to the inside of the device due to collision of beads, rotation of a pin rotor, pressure by kneaded ink, and the like, and the ink becomes a high temperature state. For this reason, a cooling mechanism for cooling the ink in the vessel is provided on the outer periphery of the vessel for kneading the ink, but in the vicinity of the centrifuge for discharging the dispersed ink, there is a gap between the centrifuge and the upper wall surface. Friction can lead to a high temperature state, which can cause ink deterioration and hardened residue, or wear of equipment components.

  As a method for suppressing the wear of the centrifuge, the centrifuge and the upper wall surface of the centrifuge are prevented from being worn by collision of beads. An installed device is disclosed (see Patent Document 1).

  However, the above-mentioned prior patent documents are intended to prevent the centrifuge and the upper part of the centrifuge from being worn, and the generation of cured residue of ink staying between the centrifuge and the upper wall surface due to frictional heat or the like. There is still a problem because it does not suppress it.

  Then, the apparatus of the centrifuge and the support disk surrounding it, and the factors that cause ink curing residue will be described. FIG. 3 shows an example of the configuration of the bead mill (10) used when the viscosity of the ink is relatively high. The bead mill (10) is configured by connecting a rotating shaft (1) driven to rotate by a motor, an ink ejection unit (A), and a dispersion / kneading unit (B) from above with respect to the rotating shaft (1). Printing ink and the like. The rotating shaft (1) and the upper part of the ink discharge section (A) are fixed and connected to the machine frame of the bead mill (10).

  Specifically, the production principle of the ink using the bead mill (10) will be explained. First, the ink is coarsely dispersed in the previous step, and then pumped from the bottom of the vessel (4) which is a dispersion / kneading tank. The pin rotor (5), which is a plurality of stirring members in the vessel (4), and the pin (6) provided on the inner peripheral surface of the vessel (4) move up while moving. At the same time, a plurality of beads (7) are filled in the gap, the pin rotor (5) is rotated in this state, and rotational and convective motions are given to the beads (7), so that the shearing force and collision between the beads and between the pins. The ink is dispersed and kneaded by force and stirring force.

  Next, FIG. 4 is an enlarged view of the ink discharge portion (A). The ink discharge unit (A) includes a rotating centrifuge (3) and a fixed upper support plate (2a) and a lower support plate (2b) that surround the centrifuge plate (3). The centrifugal separator (3) includes an upper fixed shaft (3a), an ink discharge top plate (3b), an ink discharge blade (3c), and a lower fixed shaft (3d). The packing (2c) is provided to prevent ink escape.

At this time, the ink kneaded in the vessel (4) moves to the ink discharge portion (A) through the gap between the uppermost pin rotor (5) and the lower support plate (2b), and the ink discharge blade (3c ) Is discharged from the opening (2d) of the lower support plate (2b) illustrated in the centrifugal motion.
The rotating shaft (1) is connected to a pin rotor (5) at the lower part of the centrifugal separator (3) and a vessel (4) to the lower part of the lower support board (2b). Also, as an alternative to the uppermost pin rotor (5), a donut-shaped metal plate called a gap separator that creates a gap for separating ink and beads may be provided.

  Next, ink is filled in the gap between the centrifugal separator (3) and the upper support disk (2a) and the lower support disk (2b) of the ink ejection part (A), but since the ink is press-fitted in a vacuum state, In addition to the opening (2d), the ink escapes into every gap and tries to go around. Specifically, there are a gap between the upper support plate (2a) and the ink discharge top plate (3b), and a gap between the packing (2c) between the upper support plate (2a) and the upper rotating shaft (3a).

  Therefore, an ideal mechanism is one in which the upper support plate (2a) and the upper fixed shaft (3a) of the centrifugal separator (3) and the ink discharge top plate (3b) are brought into close contact with each other, but no ink escape occurs. The board (3) rotates at high speed, and as a cooling function, the frictional heat generated by the rotation of the centrifugal separator (3) is provided in the upper support board (2a) and the lower support board (2b) as shown by the dotted line. In order to prevent the ink from changing in quality, a water-cooling device is provided, but the upper support plate (2a), the upper fixed shaft (3a) of the centrifugal separator (3), and the ink discharge top plate (3b) This is not possible because frictional heat will damage the device.

  Therefore, a gap is provided between the upper support plate (2a) and the ink discharge top plate (3b), and a cloth-like packing (2c) is packed between the upper support plate (2a) and the upper fixed shaft (3a). , Preventing ink leakage.

  However, if the gap between the upper support plate (2a) and the ink discharge top plate (3b) is too large, a large amount of ink is applied upward and pressure is applied, so the packing (2c) may move. As a result, ink leaks.

  On the other hand, if the gap between the upper support plate (2a) and the ink discharge top plate (3b) is narrow, the ink that has entered the gap is caused by frictional heat due to rotation of the centrifugal separator (3), energy due to physical contact, etc. The ink becomes hot and dry polymerizes. As a result, a part of the ink becomes a cured residue, and the residue is mixed into the ink discharged from the opening (2d). The ink in which the residue is mixed has an adverse effect on normal ink, and consequently deteriorates the storage stability of the ink, and thus adversely affects the ink quality.

  In particular, an ink mixed with a photoinitiator or the like, such as UV ink, has a big problem in the mechanism of such an apparatus because the ink is cured by high heat, physical load or energy.

JP 2001-46899 A

  The present invention has been considered in view of the above-mentioned problems, and creates an appropriate gap between the centrifuge disc of the bead mill and the ink discharge top plate, and by partially changing the shape of the concentric separator, the ink is cured. The present invention relates to a bead mill that suppresses the generation of waste and prevents problems such as ink leakage.

  The bead mill of the present invention includes a plurality of stirring members arranged at predetermined intervals in a cylindrical stirring tank, and is injected into the bead-shaped dispersion medium filled in the stirring tank and the stirring tank. In a bead mill having an agitation unit for agitating the ink-like material to be dispersed and an ink ejection unit for taking out the dispersion medium from the agitation tank to the outside of the agitation tank, the ink ejection unit is a centrifuge. The centrifuge has an upper fixed shaft, an ink discharge top plate, an ink discharge vane, and a lower fixed shaft. A predetermined gap is provided between the upper support plate and the ink discharge top plate. It is a bead mill provided with.

  In the bead mill of the present invention, the above-mentioned predetermined gap is a bead mill having a range larger than 0.5 mm and smaller than 3.0 mm.

  Further, the ink discharge top plate in the bead mill of the present invention is a bead mill provided with an inclination from the upper fixed shaft toward the edge side.

  In addition, the bead mill of the present invention is a bead mill in which the inclination angle of the ink discharge top plate is 0 degree to 4.4 degrees.

  The bead mill of the present invention has the effect of stabilizing the quality because no ink residue is formed in the gap between the upper fixed shaft and the ink discharge top plate of the centrifugal separator.

  In addition, the bead mill of the present invention eliminates the occurrence of ink leakage and the accompanying packing damage, thereby reducing the number of cleaning of the apparatus and the replacement frequency of the packing, thereby improving workability.

  In addition, since the bead mill of the present invention does not operate in a state where the ink residue remains, the upper support plate and the ink discharge top plate are not damaged, and the life of the device can be extended. There is an effect that the cost can be reduced.

The schematic diagram of the ink discharge part of this invention. The schematic diagram of the ink discharge top plate of this invention. The schematic diagram of the bead mill of the past and this invention. Schematic diagram of a conventional ink discharge unit.

  A specific configuration of the present invention will be described. However, the present invention is not limited to the embodiments described below, and includes various other embodiments within the scope of the technical idea described in the scope of claims.

  First, the main configuration of the bead mill of the present invention is the same as that in FIGS. 3 and 4 described in the background art, and is omitted.

  FIG. 1 is an enlarged view of the ink discharge section (A), similar to FIG. 4, and shows an example of a centrifuge (3 ′) that is a feature of the bead mill of the present invention. The difference from the background art is that a gap is provided between the upper support plate (2a ') and the ink discharge top plate (3b') and the shape of the ink discharge top plate (b '). In the present invention, the ink discharge top plate An inclination is provided at (3b ′).

  The reason why the problem of the present invention is solved by using the above-described centrifuge (3 ′) will be described in detail. First, when the ink discharge top plate (3b ′) is not inclined as in the background art and the gap between the upper support plate (2a ′) and the ink discharge top plate (3b ′) is narrow, the ink discharge top plate once entered the gap. The ink cannot circulate and cannot return in the direction of the opening (2d ′). As a result, the metabolism of the ink deteriorates, and ink curing residue is generated due to frictional heat caused by the rotation of the centrifuge (3 '). And adversely affects the quality of the ink.

  Therefore, in order to investigate an appropriate gap between the upper support plate (2a ′) and the ink discharge top plate (3b ′), a level of 0.5 mm or less to 3.0 mm or more is provided, The influence on the ink characteristic value, the increase in the ink temperature, and the leakage of the ink from the packing (2c ′) between the upper top plate (2a ′) and the upper fixed shaft (3a ′) were investigated. About the evaluation method, evaluation by (double-circle), (circle), and x was performed according to the result. As a result, as shown in Table 1 below, when the gap is set to 0.5 mm or less and when the gap is set to 3 mm or more, all the evaluation items are x, so in the present invention, the upper support plate (2a ′) and The appropriate gap of the ink discharge top plate (3b ′) is set to be less than 3.0 mm from a gap exceeding 0.5 mm, and more preferably within a range of 0.7 to 2.0 mm. It can be seen that no curing residue is generated and no ink leakage occurs.

  In addition, by adjusting the gap between the upper support plate (2a ′) and the ink discharge top plate (3b ′), the generation of ink curing residue and ink leakage were improved, but the problem was not solved completely. Remains. Therefore, while providing a gap, the ink discharge top plate (3b ') is inclined from the upper fixed shaft (3a') side toward the ink discharge port (2d '), so that the upper support plate (2a') and the ink discharge A space was created between the top plate (3b '). At this time, the ink that has once entered between the upper support plate (2a ′) and the ink discharge top plate (3b ′) reaches the opening (2d ′) along the inclined surface of the ink discharge top plate (3b ′). The ink was circulated in the direction, and the ink was set to circulate in the gap.

  With the above setting, the ink stays between the upper support plate (2a ') and the ink discharge top plate (3b'), so the influence of frictional heat can be suppressed and the ink can be reduced. The ink was not cured in the form of a residue and the excessive pressure applied to the ink that had entered the gap was relieved, and the occurrence of ink leakage was suppressed. As a result, by providing an inclination to the ink discharge top plate (3b '), it was possible to produce ink without causing ink curing residue and no problem of ink leakage.

  Further, the inclination angle (θ) of the ink discharge top plate (3b ′) shown in FIG. 2 is 0 to 4.4 degrees, and the inclination angle (θ) is, as shown, the upper fixed shaft (3a ′) and The angle from the connecting position of the ink discharge top plate (3b ′) to the position of the upper surface of the ink discharge top plate (3b ′) with reference to a line parallel to the upper support plate (2a ′). When the angle is 0 degree, the length from the connecting position of the upper fixed shaft (3a ′) and the ink discharge top plate (3b ′) to the end of the ink discharge top plate is l, and the ink discharge top plate (3b ′) From the relationship of the gap width (d ′) created by the inclination, the inclination angle was obtained from arctan (gap d ′ / l).

  Further, the gap (d) between the ink discharge top plate (3b ′) and the upper support plate (2a ′) on the upper fixed shaft side (3a ′), the inclination angle (θ) of the ink discharge top plate (3b ′), and the ink The level of the gap formed between the end of the discharge plate (3b ') and the upper support plate (2a') was measured, and the ink residue and ink leakage were measured. The upper support plate (2a ') and the ink discharge plate (3b) The gap (d ′) between the upper fixed shaft (3a ′) and the connecting position side of “′) is approximately 0.7 to 1.3 mm, and the gap (d ′) formed by the inclination of the ink ejection board (3b ′) is When the sum was 0.7 to 1.3 mm, and the sum was 2 mm, the curled ink residue and the ink packing (2c ′) wrap around and leakage was suppressed. Further, the inclination angle (θ) at this time is 1.5 to 2.8 degrees.

  The distance l when this experiment was conducted was 26.25 mm, and the upper fixed shaft (3a) of the upper support plate (2a ′) and the ink discharge plate (3b ′) is different even when the size of the apparatus is different. The effect was obtained when the sum of the gap (d) and the gap (d ') due to the inclination of the ink ejection board (3b') was 0.5 mm to 3 mm. .

  Next, a specific configuration of the centrifuge according to the characteristics of the ink to be produced will be described with reference to examples. The ink used in this example was UV ink having an ink viscosity of 100 to 900 poise. The reason is that it is more susceptible to quality by frictional heat or the like than kneading oil-based low viscosity ink.

  FIG. 2 shows an example of the configuration of the centrifuge (3 ′) in the bead mill of the present invention, in which only the upper support plate (2a ′) and the centrifuge (3 ′) in FIG. 1 are extracted. is there. The gap (d) between the upper support plate (2a ′) and the ink discharge top plate (3b ′) is in the range of 0.5 to 2 mm, more preferably 0.7 to 2.0 mm. . The gap (d) refers to the connecting position of the upper support plate (2a ′), the upper fixed shaft (3a ′), and the ink discharge top plate (3b ′), as shown.

  Here, when the gap was smaller than 0.5 mm, the ink was cured by frictional heat and ink residue was generated. No ink residue is observed between 0.5 mm and 0.7 mm, but the ink wraps around the packing (2c ′) between the upper discharge plate (2c ′) and the upper fixed shaft (3a ′). It is. When the thickness was 0.7 mm to 2.0 mm, no generation of ink curing residue was observed, and no wraparound and leakage of ink toward the packing (2c ′) were observed. Also, the ink temperature at this time was stable. When the gap was more than 2 mm, the ink flowed into the gap, and the upper support plate (2b ′) and the ink discharge plate (3c ′) were loaded, causing leakage from the packing (2c ′).

  Here, when the ink discharge top plate (3b ') is provided with an angle along with the gap (d), the ink that has entered the gap between the upper support plate (2a') and the ink discharge plate (3b ') Since it is easy to circulate with the ink in the part (2d ′), frictional heat is suppressed, the load on the upper support plate (2a ′) and the ink discharge plate (3b ′) is reduced, and the generation of ink residue is suppressed. . Further, a small amount of wraparound to the packing (2c ′) was observed when no inclination was provided, whereas almost no wraparound was observed when the inclination was applied.

  Further, the gap formed by the end of the ink discharge plate (3b ') and the upper support plate (2a') is the gap (d) at the connecting position between the ink discharge plate (3b ') and the upper fixed shaft (3a') and the ink discharge. When the sum of the gaps formed by the tilting of the plate becomes 2.0 mm, the curling of the ink residue and the ink packing (2c ′) can be suppressed, especially the ink discharge plate (3b ′) and the upper part. When the gap at the connecting position of the fixed shaft (3a ') is 0.7 mm to 1.3 mm and the gap (d') due to the inclination of the ink ejection board is 1.4 mm to 2 mm, the ink is most generated and the ink is packed. The wraparound was suppressed. The inclination angle (θ) at this time is 1.5 to 2.8 degrees.

  In the case of producing the above-described ink, if the structure of the present invention is used, the upper support plate (2a ′), the upper fixed shaft (3a ′) of the centrifugal separator (3 ′), the ink discharge top plate (3b ′), Ink leakage is not generated in the gap, and ink leakage from the gap of the packing (2c ′) between the upper support plate (2a ′) and the upper rotating shaft (3a ′) can be prevented. In particular, this apparatus is effective because UV ink has an ink composition that is easily cured and solidified by light / thermal polymerization.

A Ink discharge part B Dispersion / kneading part 1 Rotating shaft 2a, 2a 'Upper support plate 2b, 2b' Lower support plate 2c, 2c 'Packing 2d, 2d' Opening 3, 3 'Centrifugal disc 3a, 3a' Upper Fixed shaft 3b, 3b 'Ink ejection top plate 3c, 3c' Ink ejection blade 3d, 3d 'Lower fixed shaft 4 Vessel 5 Pin rotor 6 Pin 7 Bead d, d' Gap θ Angle

Claims (2)

A cylindrical stirring tank is provided with a plurality of stirring members arranged at predetermined intervals, and a bead-like dispersion medium filled in the stirring tank and an ink-like dispersion to be injected into the stirring tank In a bead mill equipped with an agitation part for agitating the material, and an ink discharge part for taking out the medium to be dispersed out of the agitation tank above the agitation tank,
The ink discharge part consists of a centrifuge, an upper support plate and a lower support plate,
The centrifugal separator comprises an upper fixed shaft, an ink discharge top plate, an ink discharge vane, and a lower fixed shaft,
A gap in the range larger than 0.5 mm and smaller than 3.0 mm is provided between the upper support plate and the ink discharge top plate ,
A bead mill characterized in that a predetermined inclination angle for circulating the ink is provided by providing an inclination in the downward direction from the upper fixed shaft toward the edge side of the ink discharge top plate . The bead mill according to claim 1, wherein an inclination angle of the ink discharge top plate is 1.5 degrees to 2.8 degrees .

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