JP2016135474A - Stirring apparatus and method for stirring liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stirring apparatus for stirring and mixing a mixture, in particular a liquid containing insoluble particles, that enables good mixing at a relatively low rotational speed.SOLUTION: A stirring apparatus comprises: a container containing a mixture; a rotor comprising a shaft and a rotor blade; a driving means rotating the shaft; and at least one flow disturbing object between the shaft and a circumferential inner wall of the container. The flow disturbing object is fixedly mounted such that the flow disturbing object is stationary in the container, or is mounted rotatably around the shaft and is connected to the driving means such that the flow disturbing object is rotated at a rotational speed, that is different from the rotational speed of the shaft, and/or in a rotational direction that is different from the rotational direction of the shaft. The at least one flow disturbing object is located between the shaft and a trajectory followed by the rotor blade of the rotor when in operation, and the rotor blade has a shape that directs the mixture inwardly to the at least one flow disturbing object.SELECTED DRAWING: None

Description

  The field of the invention is that of stirring devices that stir materials, generally liquids, especially liquids containing insoluble particles, printing systems comprising such stirring devices, and materials, generally liquids, especially insoluble particles. The present invention relates to a method for stirring liquids, more particularly liquid toners.

  Typical prior art mixers use one or more rotors and / or one or more anchor stirrers to stir liquids containing insoluble particles. Such mixers have the disadvantage of requiring high rotational speeds and many components in order to obtain good mixing results. Liquids that contain insoluble particles, especially liquid toners, are very thick in the static state, viscous, viscous, thin, and reduced in viscosity when vibrated, stirred, stirred or pressurized, generally thixotropic . Such non-Newtonian pseudoplastic fluids generally show that the viscosity changes with time, and the viscosity decreases when the liquid is subjected to shear stress. It is preferred to provide a simple and robust stirring device suitable for stirring thixotropic liquids.

  An object of an embodiment of the present invention is to provide a stirring apparatus that allows mixing with fewer components and a relatively low rotational speed. More particularly, an object of embodiments of the present invention is to obtain very good mixing with little energy added to the mixture.

  According to a first aspect of the present invention there is provided a stirring device for stirring a mixture, in particular a liquid, more particularly a liquid containing insoluble particles. The apparatus includes a container containing the mixture, a rotor including a shaft and a rotor blade, a driving means for rotating the shaft, and at least one flow obstruction between the shaft and the circumferential inner wall of the container. The flow obstruction is fixedly mounted in the container to be stationary, or the flow obstruction rotates at a rotational speed different from the rotational speed of the shaft and / or at a rotational direction different from the rotational direction of the shaft, It is rotatably mounted around the shaft and is connected to the driving means. In other words, at least one flow blocker rotates at a different speed, or the same speed but in the opposite direction of rotation.

  The embodiments are based on the insight of the invention, among other things, that by using a flow inhibitor, a high shear force is obtained in the mixture at a relatively low rotational speed of the rotor. Or, to put it another way, the use of flow obstructions gives a mixture less energy and is a simpler and more effective method than prior art solutions that combine multiple fast rotating rotors and / or anchor agitators Produces large shear forces and turbulence. Particularly for toner mixtures, this avoids the mixture “dissolving” due to too high temperature or friction in the mixture. In summary, embodiments of the present invention can be performed much better than prior art stirring devices.

  The agitation apparatus of the present invention is particularly useful for agitation of liquid toners, but is also used for many other liquid types or fluid materials such as gels, colloids, powder mixtures and the like.

  According to a preferred embodiment, the at least one flow obstruction is located between the shaft and the track followed by the rotor blades of the rotor during operation. As such, the rotor blades can produce a full volume of rotational flow that is inhibited at the surface of at least one flow obstruction, resulting in high shear forces and turbulence. In such an embodiment, the rotor blade is generally said to be connected to a shaft having a rotor arm that rotates above or below the flow obstruction. As shown below, in an exemplary embodiment of the invention, a plurality of rotor blades are provided, where each rotor blade is connected to a shaft through a rotor arm.

  According to a preferred embodiment, the at least one flow obstruction has a shape that obstructs the rotational flow produced by the rotor during operation and is positioned to obstruct. The flow blocker is preferably an object that does not have cylindrical symmetry with respect to the rotor shaft. Preferably, the rotor blade has a shape that moves the mixture in the direction of at least one flow obstruction during operation, and the at least one flow obstruction has a shape that obstructs the flow produced by the rotating blade. .

  According to a preferred embodiment, the container is associated with a maximum filling level and the rotor blade extends to a height of at least 50%, preferably at least 70%, more preferably at least 80% of the maximum filling level. . Alternatively, a plurality of rotor blades that together cover at least 50% of the maximum fill level, preferably a plurality of rotor blades that cover at least 70%, more preferably at least 80% are provided.

  Preferably, the at least one flow obstruction extends radially from the shaft to the inner circumferential wall of the container by a distance of at least 15% of the maximum distance between the shaft and the inner wall of the container, more preferably at least 25%, Most preferably it extends a distance of at least 50% of the maximum distance between the shaft and the inner wall of the container. When multiple flow obstructions are used, it is the sum of the radial dimensions of the different objects that meet the above requirements in the preferred embodiment. This ensures a good agitation of the total volume between the shaft and the inner wall of the container.

  In a preferred embodiment, the flow obstruction is a stator body that is mounted in a fixed position within the container. Such an embodiment has the advantage of having a simple structure that produces excellent stirring results for relatively low energy inputs.

  In an exemplary embodiment, the at least one flow inhibitor comprises a flow inhibition plate. In another exemplary embodiment, the at least one flow obstruction comprises a columnar body, eg, a hollow column. In other embodiments, the at least one flow inhibitor comprises a level gauge, a pressure sensor, a temperature sensor, a sensor that measures the properties of the mixture, eg, a conductivity sensor that measures the electrical conductivity of the mixture, and measures the viscosity of the mixture. And a hollow body including at least one measuring device such as a viscosity sensor for measuring the density of the mixture and a density sensor for measuring the density of the mixture. This hollow body is fixed to or through the upper cover and opened at the lower end. The upper end is opened or closed. Alternatively, the hollow body is fixed to the lower part of the container and has an open upper end. The hollow body is provided with a plurality of holes for facilitating the flow of new mixture through the hollow body.

  In a further developed embodiment, the distance between the at least one flow blocker and the rotor shaft is less than 5 cm, preferably less than 3 cm. Preferably this applies to a substantial part of the height of the flow obstruction, more preferably to the whole area where at least one flow obstruction and the shaft are in the mixture. As such, “uninterrupted” or “undisturbed” flow between the shaft and the flow obstruction is significantly reduced or avoided. The optimum distance is generally determined by the viscosity of the mixture, which value is set to give good results, especially for liquid toner mixtures.

  In a preferred embodiment, during operation, the distance between the at least one flow blocker and the track followed by the rotor blades of the rotor is less than 5 cm, preferably less than 3 cm. Preferably this applies to a substantial part of the height of the flow obstruction, more preferably to the entire area where at least one flow obstruction and the rotor blade are in the mixture. . As such, “uninterrupted” flow between the rotor blades and the flow obstruction is significantly reduced or avoided.

  The rotor blade comprises at least one opening arranged to allow the mixture to pass through the at least one opening.

  Preferably, the rotor blade is an elongated upright rotor blade extending substantially parallel to the upstanding side of the at least one flow obstruction. In such embodiments, the opening is a slit that extends in the elongated rotor blade. More preferably, the rotor blade comprises a first upstanding elongated portion connected to an adjacent second upstanding elongated portion, the first portion having an angle with the second portion, and the mixture is a flow inhibitor. In the direction of rotation of the rotor during rotation. More generally, the rotor blade preferably has a shape that faces the mixture relative to the flow obstruction, and if the flow obstruction is located between the shaft and the rotor blade, it faces inward and the flow obstruction Faces outward when positioned between the inner wall and the rotor blade.

  In the exemplary embodiment, the elongated upright rotor blades extend substantially vertically and in particular parallel to the shaft.

  In another example embodiment, the elongate upright rotor blade extends at an angle greater than 90 degrees relative to a horizontal line that contacts the rotor trajectory so that the rotor blade tilts backward when looking at the direction of rotor rotation. Such an angle improves the stirring in the vertical direction by moving the mixture upwards. In other embodiments, the elongated rotor blade has a curvilinear shape, eg, a helical shape. When the rotor blades are tilted rearward when viewed in the direction of rotation of the rotor, or when the rotor blades have a spiral shape that appears to bend backwards when viewed in the direction of rotation of the rotor, the rotor blades Push the mixture upwards. The upper movement of the mixture at least partially offsets the lower movement behind the flow inhibitor and further improves mixing, especially when mixing at relatively low rotational speeds. The rotor blade angle is optimized to produce a closed curvilinear motion, for example a circular or elliptical motion of the mixture in a plane perpendicular to the direction of rotor rotation.

  In yet another example embodiment, the elongate rotor blades extend at an angle of less than 90 degrees with respect to a horizontal plane that is in contact with the rotor track so that the rotor blades tilt forward when viewing the direction of rotor rotation. . Such an angle improves stirring in the vertical direction by moving the mixture downward. In another embodiment, the elongated rotor blade has a curved shape extending forward as viewed in the direction of rotation of the rotor. When the rotor blades are tilted forward when viewed in the direction of rotation of the rotor, or when the rotor blades have a spiral shape that appears to be curved forward when viewed in the direction of rotation of the rotor, the rotor blades are Push the mixture downwards. Also here, the angle of the rotor blades is optimized to produce a closed curvilinear motion, for example a circular or elliptical motion of the mixture in a plane perpendicular to the direction of rotor rotation.

  Preferably, the outer edge of the elongated rotor blade extends parallel or substantially parallel to the inner wall of the container, but this outer edge extends, for example vertically or spirally, in a plane parallel to the inner wall of the container.

  According to a further exemplary embodiment of the invention, the stirring device is defined by any one of the following sections.

  1. A stirrer for stirring a mixture, in particular a liquid containing insoluble particles, comprising a container containing the mixture, a rotor comprising a shaft and rotor blades, a drive means for rotating the shaft, the circumference of the shaft and the container At least one flow obstruction between the inner wall and the flow obstruction is fixedly mounted in a stationary manner in the container, or the flow obstruction is different from the rotation speed of the shaft, And / or is rotatably mounted about the shaft so as to rotate in a direction of rotation different from the direction of rotation of the shaft and connected to the drive means, wherein at least one flow obstruction is provided between the shaft and the rotor during operation. Located between the track followed by the rotor blades, the rotor blades have a shape that directs the mixture upwards and / or downwards. .

  2. The agitation device of clause 1, wherein the rotor blade has a shape that directs the mixture inward with respect to at least one flow blocker.

  3. The agitating device of clause 1 or 2, wherein the rotor blades, when viewed in the direction of rotation of the rotor, are arranged so that the rotor blade is tilted at least partly backward and / or at least partly forward. When viewed, an elongated rotor blade that extends at an angle of greater than 90 degrees or less than 90 degrees with respect to a horizontal plane in contact with the rotor trajectory.

  4). The agitating device of any one of the preceding clauses, wherein the rotor blade has a substantially helical shape disposed about the rotor shaft.

  5. The agitator of any one of the preceding clauses, wherein the rotor blade comprises a first elongated portion and a second elongated portion, the first elongated portion having an angle with respect to the second elongated portion. , The mixture moves towards at least one flow obstruction during the rotation of the rotor.

  6). The agitator of any one of the preceding clauses, wherein the rotor is an elongated rotor blade having a longitudinal direction, the rotor blade being arranged to allow the mixture to pass through at least one opening. An opening is provided, and the opening is a slit extending in the length direction.

  7). The agitator of any one of the preceding sections, wherein the at least one flow inhibitor comprises a flow inhibition plate.

  8). The agitation device of any one of the preceding clauses, wherein the at least one flow obstruction is a stator body that is attached to a fixed location within the container.

  9. The agitation device of any one of the preceding sections, wherein the at least one flow blocker comprises a hollow body comprising at least one measuring device.

  10. The agitator of any one of the preceding clauses, wherein the rotor blade is secured to the shaft by means of an arm extending from the shaft in the direction of the circumferential inner wall of the container, preferably the arm comprises the rotor blade and the shaft And an elongated slit extending in the radial direction.

  11. The agitating device of any one of the preceding clauses, wherein the container is a cylindrical container having an inner wall that extends the distance of the track followed by the rotor blade, the distance is preferably less than 5 cm, more preferably Smaller than 3 cm.

  12 A printing system comprising: a printing device comprising a toner supply unit and a toner discharge line; and the stirring device of any one of the preceding sections, wherein the liquid toner is stored in a container of the stirring device, the container being And having an outlet and an inlet for discharging the stirred liquid toner, the outlet being connected to a toner supply unit of the printing device and the inlet being connected to a toner discharge line.

  In a preferred embodiment, the rotor blade is fixed to the shaft by means of an arm extending from the shaft in the direction of the inner circumferential wall of the container. Preferably, the distance between the at least one flow blocker and the region in which the rotor arm rotates is less than 5 cm during operation, more preferably less than 3 cm. Preferably this is applied in all areas where the mixture is present. The optimum distance is generally determined by the viscosity of the mixture, which value is set to give good results, especially for liquid toner mixtures.

  In a preferred embodiment, each arm of the at least one arm comprises an elongated slit extending in the radial direction between the rotor blade and the shaft. In addition, each arm of the at least one arm includes a first elongate portion and a second elongate portion, the first and second portions being adjacent portions that extend radially between the shaft and the inner wall of the container. The first part has an angle with respect to the second part, and the mixture moves upward and / or downward during the rotation of the rotor. More generally, the arm is preferably shaped to direct the mixture to the flow obstruction when the flow obstruction is located above the rotor blade and upward when the flow obstruction is located below the rotor arm. have.

  In a preferred embodiment, the container is a cylindrical container. Preferably, the inner wall of the container extends by the distance of the track followed by the rotor blade, the distance being less than 5 cm, preferably less than 3 cm. Preferably, the outer part of the rotor blade is angled with respect to the radial direction so that the mixture is removed from the inner wall of the container. The optimum distance is generally determined by the viscosity of the mixture, which value is set to give good results, especially for liquid toner mixtures.

  In a preferred embodiment, the rotor comprises one or more additional rotor blades. Such additional rotor blades have one or more features of the first rotor blade described above. Preferably, the different rotor blades of the rotor are arranged symmetrically around the shaft.

  Preferably, the container has a conical bottom wall with an outlet located approximately near the bottom of the conical bottom wall, and the stirred liquid is easily released.

  In a further developed embodiment, the stirring device further comprises an inlet tube having an end where the mixture leaves the inlet tube. Preferably, the end is located between the shaft and the rotor blade. Thus, the mixture is brought into the container at an appropriate location within the container when the shear force is very high. The inlet tube is placed on the top cover of the container.

  In a preferred embodiment, the drive means is configured to rotate the rotor at a rotational speed of less than 120 revolutions / minute, preferably 50-100 revolutions / minute, more preferably 50-80 revolutions / minute. Is done.

  According to a possible embodiment, the flow obstruction is rotatably mounted around the shaft such that the flow obstruction rotates at a lower rotational speed than the rotational speed of the shaft and / or has a different direction of rotation and is attached to the drive means. It is connected. In this way, the flow blocker functions in the same way as the above-described stator body, and good stirring uses only one motor as a driving means for driving both the rotor and the flow blocker at a relatively low rotational speed. Obtained in a simple way to demand.

  In an exemplary embodiment, the agitation device further comprises a wave guide portion above the trajectory followed by the rotor blade, the wave guide portion being configured to guide the upwardly extending wave downward in the container. ing. In general, rotation of the mixture by the rotor causes the shape of the surface of the rotating mixture to be recessed as a result of centrifugal force. Furthermore, the passage of the rotor blades creates waves that extend beyond the top surface of the container at high mixture levels in the container. By adding a wave guide, waves are blocked and guided downward and / or inward in the container. In this way, the need for a container height greater than the maximum mixture level is avoided, resulting in a more compact device.

  According to a second aspect of the present invention, there is provided a printing system comprising a printing device comprising a toner supply unit and a toner release line and at least one agitation device of any one of the embodiments described above. Liquid toner is stored in a container of the agitator device, the container having an outlet and an inlet for discharging the agitated liquid toner. The outlet is connected to the toner supply unit of the printing apparatus, and the inlet is connected to the toner discharge line. The toner supply unit includes, for example, a main reservoir and a supply roller that is supplied by liquid toner in the main reservoir. The outlet of the agitator container is connected to the inlet of the main reservoir of the toner supply unit. The toner release line is a liquid toner that needs to be stirred from the printing device, such as liquid toner from the main reservoir and excess toner from the printing device, such as toner that is removed from the supply or development roller during printing. To collect.

  In a preferred embodiment, the printing system further comprises one or more of the following. It is a reservoir for storing a dispersed substance, the dispersed substance reservoir is connected to the inlet of the container via a dispersed substance administration unit, and is a reservoir for storing a carrier liquid, and the carrier liquid reservoir is a carrier liquid administration unit And a stirring device according to any one of the embodiments described above. In this, the container of the further agitation device stores a concentrated solution of liquid toner, and the container of the further agitation device is connected to the inlet of the container for storing the liquid toner via a concentrated solution administration unit. Has an exit that is. This can adjust the composition of the liquid toner in the agitator container as needed.

  In a further developed embodiment, the printing system further comprises at least one of one or more measuring devices for measuring one or more properties of the liquid toner, a dispersion substance dispensing unit, a carrier liquid dispensing unit and a concentrated solution dispensing unit. A control unit configured to control at least one measured characteristic function.

  In an exemplary embodiment, the printing system further comprises a supply reservoir and a return line that returns excess liquid toner to the supply reservoir, and the agitation device is included in the return line.

  According to another aspect of the present invention, there is provided a method for mixing a mixture using a stirring device according to any one of the embodiments described above. Preferably, the rotor rotates at a rotational speed of less than 120 revolutions / minute, preferably 50-100 revolutions / minute. The mixture is a liquid toner comprising carrier liquid, marking particles and a dispersed material.

  In an exemplary embodiment, the mixture has a dynamic viscosity in the mixed state of 3 to 500 mPa.s. s. Range. This viscosity of the mixture is measured, for example, at 25 ° C. with a Haake Rheostress RS6000 operated with a shear rate sweep of 0.1 to 30001 / s, mPas. It is represented by The viscosity measuring device comprises a cone / plate shape type C60 / 1 ° and the gap is set to 0.052 mm, for example. In a preferred embodiment, the mixture is an ink mixture, for example, an electrophotographic printing e-liquid toner or an ink jet printing ink mixture. The agitation apparatus according to embodiments of the present invention is particularly advantageous with mixed suspensions where Brownian motion cannot avoid deposition.

  The accompanying drawings are used to illustrate presently preferred non-limiting exemplary embodiments of the apparatus of the present invention. The above and other advantages of the features and objects of the present invention will become more apparent and understood more fully from the following detailed description when read in conjunction with the accompanying drawings.

It is a schematic perspective view of 1st Embodiment of the stirring apparatus of this invention. It is a schematic perspective view of 1st Embodiment of the stirring apparatus of this invention. It is a schematic perspective view of 1st Embodiment of the stirring apparatus of this invention. It is sectional drawing through the perpendicular | vertical surface of the shaft of 1st Embodiment. It is sectional drawing of 2nd Embodiment. It is sectional drawing of 3rd Embodiment. It is sectional drawing of 4th Embodiment. It is a figure of 1st Embodiment of the printing system of this invention. It is a figure of 2nd Embodiment of a printing system. It is a figure of 3rd Embodiment of a printing system. It is a figure of the further modification of the stirring apparatus of this invention. It is a figure of the further modification of the stirring apparatus of this invention. It is a schematic perspective view of 4th Embodiment of the stirring apparatus of this invention. It is a top view of 4th Embodiment of the stirring apparatus of this invention. It is a 1st schematic perspective view of 5th Embodiment of the stirring apparatus of this invention. It is a 2nd schematic perspective view of 5th Embodiment of the stirring apparatus of this invention. It is a top view of 5th Embodiment of the stirring apparatus of this invention. It is a longitudinal cross-sectional view of 5th Embodiment of the stirring apparatus of this invention. 1 is a first schematic perspective view of an embodiment comprising a helical rotor blade that curves backward; FIG. FIG. 6 is a second schematic perspective view of an embodiment comprising a helical rotor blade that curves backwards. It is a 1st schematic perspective view of other embodiment provided with the helical rotor blade curving back. FIG. 6 is a second schematic perspective view of another embodiment including a spiral rotor blade that curves backward. 1 is a first schematic perspective view of an embodiment comprising a helical rotor blade with a hole that curves backwards. FIG. FIG. 6 is a second schematic perspective view of an embodiment comprising a helical rotor blade with a hole that curves backwards. 1 is a first schematic perspective view of an embodiment comprising a helical rotor blade with a forward curved hole. FIG. FIG. 6 is a second schematic perspective view of an embodiment comprising a helical rotor blade with a forward curved hole.

  1A-1C and 2 show a first embodiment of a stirring device for stirring a liquid L, in particular a liquid containing insoluble particles, more particularly a liquid toner comprising carrier liquid, marking particles and a dispersing substance.

  In a xerographic process operating with liquid toner, image particles or marking particles are supplied as solid particles floating in a carrier liquid. The image particles are made of pigment particles and are generally incorporated into small beads of resin. Dispersing material or dispersant is added to the mix to avoid clustering of marking particles. The dispersant prevents the image particles from agglomerating and lowers the viscosity of the liquid toner dispersion. The carrier liquid comprises any suitable liquid known in the art, such as silicon fluid, mineral oil, low or high viscosity liquid paraffin, isoparaffin hydrocarbon, fatty acid glyceride, fatty acid ester, vegetable oil, chemically modified vegetable oil, or their Contains any combination. The carrier liquid further includes variable amounts of charge control material (CCA), waxes, plasticizers, and other additives, which are also incorporated into the toner particles themselves. The carrier liquid is volatile or non-volatile. An exemplary digital printing system using liquid toner is described in more detail in US Patent Application No. 2009/0052948, the contents of which are hereby incorporated by reference in their entirety. Generally, the liquid toner has a solid concentration between 5% and 60 wt%. The high shear viscosity is preferably in the range of 5 to 500 mPa · s, measured at a shear rate of 3000 s −1 at 25 ° C. in a C60 / 1 ° cone plate shape with a gap of 52 μm.

  The stirring device of the first embodiment includes a container 30 containing a liquid L, a rotor 10, and a flow obstruction in the form of a stator body 40. The container 30 includes a bottom portion, preferably a conical inner wall, and an upper cover 90 and a cylindrical body between the bottom portion and the upper cover 90. The rotor 10 has a shaft 17 having two arms 11 each having a rotor blade 12. The stator body 40 is formed as a stator plate, and is fixedly attached between the shaft 17 and the cylindrical inner wall of the container 30.

  Although the illustrated embodiment comprises a rotor 10 with two arms 11 and two rotor blades, those skilled in the art will appreciate that one arm or more than two arms may be provided. Furthermore, more than one stator body 40 may be provided. Further, instead of the cylindrical shape, the container 30 may have a box shape, and the stator body 40 may include a through hole to allow liquid to pass through the stator body.

  In the first embodiment, the stator body 40 is located between the shaft 17 and the track T (see FIG. 2) followed by the rotor blades 12 of the rotor 10 during operation. The stator body 40 is shaped and positioned to impede the rotational flow generated by the rotor in use. In other words, the stator body 40 should not be rotationally symmetric about the shaft 17. The stator body 40 is at least 25% of the maximum distance D between the shaft 17 and the inner wall of the container 30, preferably from the shaft 17 to the inner wall of the container 30, as shown in FIG. A distance DS, which is at least 50% of the maximum distance D between them, extends in the radial direction. In this way, the rotational flow generated by the rotor is impeded and high shear forces are produced, resulting in good mixing and stirring of the liquid. In general, the surface of the liquid is generally flat in the quadrant behind the flow blocker 40, particularly during stirring, and does not have the conical shape of prior art mixers. This roughly flat surface also provides greater potential for placement of level sensors that measure the liquid level of the container. In the illustrated embodiment, a hollow body 80 is provided that is attached to the upper cover 90 and forms a housing for the level sensor. The use of the hollow body 80 as a level sensor housing further improves the accuracy of the measurement.

  The distance d1 between the stator body 40 and the shaft 17 of the rotor 10 is a substantial part of the height of the stator body 40, preferably at least 70% of the height of the stator body 40, preferably less than 5 cm, preferably Smaller than 4 cm. Similarly, the distance d2 between the stator body 40 and the track T followed by the rotor blades 12 of the rotor 10 is a substantial portion of the height of the stator body 40 during operation, preferably the height of the stator body 40. At least 70% of the thickness is less than 5 cm, preferably less than 3 cm. The distance d2 is between 2.5 cm and 4 cm. The distance d3 between the stator body 40 and the arm 11 of the rotor 10 is a substantial part of the length of the arm 11 when the arm 11 is located below the stator body 40, and preferably the length of the arm 11 At least 70% of the thickness is less than 5 cm, preferably less than 3 cm.

  The rotor blade 12 is an elongated upright rotor blade that extends substantially parallel to the upstanding side surface of the stator body 40. The rotor blade 12 includes an opening in the form of an elongated slit 19 that extends in the lengthwise direction of the rotor blade 12 and is arranged to allow liquid to pass through the slit 19. The rotor blade 12 includes a first upright elongated portion 13 adjacent to the inner wall of the container 30. The first elongated portion 13 is connected to the second upright elongated portion 14 adjacent to the end of the stator body 40. The first part 13 has an angle with respect to the second part 14 when viewed in a cross section perpendicular to the shaft 17 (see FIG. 2), and the liquid moves inward during the rotation of the rotor 10. As shown in FIG. 1, the elongated plate element is bent and cut to form the rotor blade 12. The rotor blades 12 are preferably positioned such that at least the outer portion of each rotor blade 12 is angled with respect to the radial direction so that liquid is removed from the inner wall of the container 30.

  Similarly, each arm 11 is provided with an elongated slit 20 extending radially between the rotor blade 12 and the shaft 17, the slit being arranged to allow liquid to pass through. Each arm 11 includes a first elongated portion 15 and a second elongated portion 16, and the first and second portions 15, 16 are adjacent to each other and extend in the radial direction between the shaft 17 and the inner wall of the container 30. Part. The first part 15 has an angle with respect to the second part 16 when viewed in a cross section perpendicular to the arm 11. The angle is such that the liquid moves upward during the rotation of the rotor 10. Also, the arm 11 is easily formed by bending and cutting the elongated plate element.

  Preferably, the distance d4 between the inner wall and the track T followed by the at least one rotor blade 12 is less than 5 cm, more preferably less than 3 cm. The distance d4 is, for example, between 0.1 cm and 3.0 cm. By reducing the distances d2 and d4, the required rotational speed required to obtain sufficient shear is reduced, avoiding that air is mixed in the mixture. The lower limit of the distance generally depends on the tolerances of the components used and / or the type of material being stirred.

  In order to avoid or reduce the sticking of liquid toner to the rotor 10, these components are appropriately coated or polished on the inner wall of the stator body 40 or the container 30.

  The agitation device of the first embodiment further comprises an inlet tube 60 having an end from which liquid leaves the inlet tube 60, the end being a top view of the agitation device and the shaft 17 and at least one rotor blade 12. Located between. Thus, the liquid enters the container 30 at a position where good stirring is achieved.

  The stirring device further comprises a drive means, generally a rotor around the shaft 17 at a rotational speed of preferably less than 120 revolutions / minute, more preferably between 90 and 100 revolutions / minute. A motor (not shown) configured to rotate 10 is provided. The motor is attached to the cover 90 of the container 30.

  FIG. 3 shows a modification of the first embodiment. In the embodiment of FIG. 3, the stator body 40 is a hollow cylinder including a measuring device, for example, a sensor 50. In this embodiment, only one arm 11 (not visible in the cross-sectional view of FIG. 3) with a rotor blade 12 is provided. Measuring devices that may be included in the hollow body 40 are level gauges, pressure sensors, temperature sensors, sensors that measure the properties of the mixture, eg, conductivity sensors that measure the electrical conductivity of the mixture, and measure the viscosity of the mixture A viscosity sensor that measures the density of the mixture. The hollow body 40 is fixed to an upper cover (not shown) and is open at the bottom end. Alternatively, the hollow body 40 is fixed to the bottom of the container 30 and has an opening at the upper end. The hollow body 40 includes a plurality of holes to facilitate the flow of fresh mixture through the hollow body 40. Further, the hollow body 40 is provided with an inlet 60. Alternatively, the inlet 60 ends inside the container and outside the hollow body. According to yet another variant, two hollow bodies 40 are provided, a first hollow body comprising a measuring device and a second hollow body in which the inlet terminates in or on.

  FIG. 4 shows a third embodiment of the stirring apparatus of the present invention. The device is similar to the second embodiment of FIG. 3 with the difference that the stator body 40 is a hollow column with a rectangular cross section. Although not shown, the measuring device is provided in the hollow body 40 as in the embodiment of FIG.

  FIG. 5 shows a cross-sectional view of a fourth embodiment of the agitation apparatus provided with the first and second stator bodies 40a, 40b provided with the first and second through holes 41a, 41b, respectively. In this embodiment, the stator bodies 40a, 40b are located near or against the inner wall of the container 30 between the inner wall and the track followed by the rotor blades during use. The rotor arm 11 connects the rotor blade 12 to the shaft 17. The rotor arm 11 is relatively short compared to the previous embodiment, and the rotor blade 12 has a shape that pushes liquid outward in the direction of the stator bodies 40a, 40b. In the embodiment of FIGS. 3 and 4, the stator elements 40a, 40b may be hollow elements comprising a measuring device. The variation of FIG. 5 is useful for liquids with lower viscosity, and the rotational speed is higher than in the embodiment of FIG.

  FIG. 6 shows a first embodiment of the printing system of the present invention. The printing system includes a digital printing apparatus 200 that uses liquid toner, a stirring apparatus 100, and a plurality of reservoirs 300, 400, and 500. The digital printing apparatus 200 includes a toner supply unit (not shown) and a toner discharge line. The agitation device 100 is embodied by any one of the example embodiments disclosed in FIGS. 1-5, and the liquid toner is stored in a container of the agitation device. The container has an outlet and an inlet for discharging the stirred liquid toner. The outlet is connected to the toner supply unit of the printing apparatus 200, and the inlet is connected to the toner discharge line. The plurality of reservoirs includes a reservoir 300 for storing a dispersed substance (DA), which is connected to the inlet of the container of the agitating device 100 via the dispersed substance administration unit 301 and is supplied with a carrier liquid (CL ), And the carrier liquid reservoir 400 is connected to the inlet of the container of the agitation device 100 via the carrier liquid administration unit 401 and includes the reservoir 500 for storing the concentrated liquid toner solution. The concentrated solution reservoir 500 is connected to the inlet of the container of the stirring device 100 via the concentrated solution administration unit 501. The concentrated solution reservoir 500 is part of a further agitation device, as also shown in FIG.

  In the embodiment of FIG. 6, the stirring device 100 is provided with at least one measuring device 150. The measuring device 150 is a level gauge, a pressure sensor, a temperature sensor, a sensor that measures the characteristics of the mixture, for example, a conductivity sensor that measures the electrical conductivity of the mixture, a viscosity sensor that measures the viscosity of the mixture, and measures the density of the mixture. Any one or more of a density sensor or the like. The measurement is performed by a control unit (not shown, but not device 150 and doser) configured to control at least one of the dispersive substance dosing unit 301, the carrier liquid dosing unit 401, and the concentrated solution dosing unit 501 in the function of the measurement. (Included in broken lines between units 301, 401, 501).

  FIG. 7 shows a variation of the embodiment of FIG. 6 in which one or more measuring devices 250 are included in a separation line that connects the outlet of the container of the stirring device 100 with its inlet. In a manner similar to that in the embodiment of FIG. 6, the measurement is a control configured to control at least one of the dispersive substance dispensing unit 301, the carrier liquid dispensing unit 401, and the concentrated solution dispensing unit 501 in the function of the measurement. Collected by a unit (not shown, but included in the dashed line between device 250 and dosing units 301, 401, 501).

  FIG. 8 shows a further variation of the printing system that combines the features of the embodiments of FIGS. In this embodiment, some measurements are made by one or more measurement devices 150 in the container of the agitation device 100 and other measurements are made by one or more measurement devices 250 in the return line. FIG. 8 further shows the printing apparatus 200 in more detail. The printing apparatus 200 includes a supply unit that includes a supply roller 220 and a supply reservoir 211 (in the main reservoir 210) in which the supply roller 220 rotates. The liquid toner on the supply roller 220 moves to the developing roller. Excess liquid toner from the supply roller 220 or the developing roller 230 or a further roller (not shown) between the developing roller 230 and the substrate is supplied to the main reservoir 210. In order to maintain a good quality liquid toner in the supply reservoir 211, a portion of the liquid and toner is returned to the agitation device 100 for agitation and fresh agitated liquid toner is transferred from the agitation device 100 to the main reservoir 210. It is supplied to the supply reservoir 211. The concentrated solution of liquid toner is stored in a container of a further agitator device 500, which further has an outlet connected to the inlet of the agitator device 100 via a concentrated solution administration unit 501. . The measurement is performed by a control unit (not shown, but not shown in the apparatus 150, 250) configured to control at least one of the dispersive substance administration unit 301, the carrier liquid administration unit 401, and the concentrated solution administration unit 501 in the function of measurement. And the dosing units 301, 401, 501).

  Figures 9 and 10 show two further embodiments comprising a flow inhibitor 40 mounted for rotation. The embodiment of FIG. 9 is similar to the embodiment of FIG. 1 with the difference that a flow inhibitor 40 is rotatably mounted about the shaft 17 and connected to the shaft 17 using, for example, a hollow shaft reduction mechanism. The flow blocker 40 rotates at a rotational speed ω2, ω2 ′ different from the rotational speed ω1 or the rotational direction of the shaft 17 and thus the rotor. When the rotation direction of the rotor 10 is opposite to the rotation direction of the flow inhibitor 40, the value of the rotation speed ω1 is the same as or different from the value of the rotation speed ω2 '. Preferably, the rotational speeds ω2 and ω2 'of the flow blocker 40 are lower than the rotational speed ω1 of the rotor.

  FIG. 10 shows an embodiment comprising two pairs of rotor blades 12, 12 'rotating at rotational speeds ω1, ω2, where ω2 and ω1 are the same or different. The rotational speed ω1 of the first pair 12 and the ω2 of the second pair 12 'are preferably the same. The flow obstruction 40 rotates in the same rotational direction as the rotor blades 12, 12 ', in which case the rotational speed ω3 is preferably less than ω1. Alternatively, the rotation direction of the rotor blades 12, 12 'is opposite to the rotation direction of the flow blocker 40, and in this case, the value of the rotation speed ω3 is the same as or different from the value of the rotation speed ω1.

  The embodiment of FIGS. 9 and 10 is a little more complex than the embodiment with a fixed stator body, but gives good agitation results at lower rotational speeds compared to prior art solutions.

  11A and 11B show a fourth embodiment that is similar to the first embodiment. The stirring device comprises a container with a cylindrical inner wall (not shown) for containing the mixture, a rotor 10 and a flow obstruction in the form of a stator body 40. The rotor 10 has two arms and two elongated rotor blades 12 extending upward. The stator body 40 is formed as a stator plate, and is fixedly attached between the shaft 17 and the cylindrical inner wall of the container. In this embodiment, the stator body 40 includes an outwardly projecting upper portion 45 that extends above the track followed by the rotor blade 12. The stator body 40 includes a fixing lip 42 that fixes the stator body to a cover (not shown). The top 45 avoids mixing being directed upward with respect to the cover. This is understood as follows. The rotation of the mixture by the rotor 10 causes the surface shape of the rotating mixture to dent as a result of centrifugal force. Furthermore, the passage of the rotor blade 12 produces waves that extend beyond the top of the container at high mixing levels of the container. By adding the upper part 45, the waves are disturbed and guided down and / or inside the container. In this way, the need for a container height greater than the maximum mixture level is avoided, resulting in a more compact device.

  The upper portion 45 is referred to as a separate part instead of being formed integrally with the stator body. More generally, a wave guide is provided above the trajectory followed by the rotor blades 12 configured to guide upwardly extending waves downward in the vessel.

  Other configurations, dimensions, and details described above as the first embodiment are similarly applied to the fourth embodiment, and description thereof is omitted.

  12A, 12B, 12C and 12D show a fifth embodiment that is similar to the fourth embodiment, the difference being that the rotor blade 12 does not extend vertically, as shown in FIGS. 12B and 12C. When viewed in the rotational direction R, the angle α is greater than 90 degrees with respect to a horizontal line in contact with the trajectory of the rotor 10. This angle α improves the agitation in the upward direction because the rotor blade 12 pushes the liquid not only along the circular trajectory but also upwards. In other words, the rotor blade 12 is inclined rearward when viewed in the rotation direction R. In this way, the rotor blade 12 pushes the mixture in the container inward and upward. The upward movement of the mixture at least partially offsets the downward movement behind the flow inhibitor 40. The angle α is optimized to produce a closed curvilinear motion, for example a circular or elliptical motion of the mixture in a plane perpendicular to the direction of rotation of the rotor 10.

  In another embodiment not shown, the rotor blade 12 extends in an angle α less than 90 degrees with respect to a horizontal line in contact with the trajectory of the rotor 10 when viewed in the rotational direction R. This angle α improves the agitation in the downward direction, since the rotor blade 12 pushes the liquid downward as well as along the circular trajectory. In yet another not shown embodiment, the rotor blade 12 extends partially rearward and partially forward when viewed in the direction of rotation R.

  In other words, the outer edge 112 of the rotor blade 12 extends vertically (FIGS. 11A and 11B) or diagonally (at an angle α), as in the embodiment of FIGS.

  FIGS. 13A and 13B show a sixth embodiment that is similar to the fifth embodiment, as shown in FIGS. 13A and 13B, at an angle α that is greater than 90 degrees with respect to a horizontal line that contacts the track of the rotor 10. An upwardly extending rotor blade 12 is provided. In this embodiment, the rotor blade is a curved blade that extends helically around the shaft 17. Preferably, the outer edge 112 of the elongate upright rotor blade 12 extends parallel to the inner wall of the container, ie the outer edge 112 extends at a cylindrical surface having an axis corresponding to the axis of the shaft 17. In the embodiment of FIG. 13A, the rotor 10 comprises one arm 11 and one rotor blade 12, and the flow obstruction is omitted for reasons of clarity. In the embodiment of FIG. 13B, the rotor 10 comprises two arms 11 and two rotor blades 12, and FIG. 13B further shows a flow obstruction 40. The rotor 10 rotates in the direction of the arrow R so that the rotor blade 12 curves backward when viewed in the rotation direction R. In this way, the rotor blade 12 pushes the mixture in the container inwards and upwards. The upward movement of the mixture at least partially offsets the downward movement behind the flow inhibitor 40. The curvature is optimized to produce a closed curvilinear motion, for example a circular or elliptical motion of the mixture in a plane perpendicular to the direction of rotation of the rotor 10.

  FIGS. 14A and 14B show an embodiment that is similar to the embodiment of FIGS. 13A and 13B, the difference being that the blades 12 move the mixture primarily upward and in the direction of rotation but not inward or substantially inward. It has a shape to be moved. In a cross section perpendicular to the shaft 17, the blades 12 are oriented in the radial direction, and in the embodiment of FIGS. 13A and 13B, the rotor blades are angled relative to the radial direction when viewed in a cross section perpendicular to the shaft 17. It is suitable. In the embodiment of FIG. 14A, the rotor 10 comprises one arm 11 and one rotor blade 12, and the flow obstruction is omitted for reasons of clarity. In the embodiment of FIG. 14B, the rotor 10 includes two arms 11 and two rotor blades 12, and FIG. 14B further shows a flow obstruction 40. The upward movement of the mixture causes a “breaking” of the mixture at the surface of the mixture in the container and at least partially offsets the downward downward movement of the flow inhibitor 40.

  15A and 15B show a seventh embodiment that is similar to the sixth embodiment, the difference being that the rotor blade 12 differs from the first helical elongate portion 13 adjacent to the inner wall of the container (not shown). A second helical elongated portion 14 adjacent the edge of the stator body 40 (not shown in FIG. 15A but visible in FIG. 15B). The first part 13 has an angle with respect to the second part 14 when viewed in a cross section perpendicular to the shaft 17. The bending and orientation of the first part 13 and the second part 14 is such that fluid moves inward and upward by the first part 13 and outward and upward by the second part 14 during rotation of the rotor 10. . The first part 13 is preferably positioned at an angle with respect to the radial direction so that the liquid is removed from the inner wall of the container 30. The rotor blade 12 is provided with a hole in the shape of an elongated slit 19 extending between the first spiral elongated portion 13 and the second spiral elongated portion 14 so that liquid can pass through the slit 19. This increases turbulence and increases mixing. In the embodiment of FIG. 15B, the rotor 10 includes two arms 11 and two rotor blades 12, and FIG. 15B further shows a flow obstruction 40.

  16A and 16B show an embodiment that is similar to the embodiment of FIGS. 15A and 15B, the difference being that the bending and orientation of the first part 13 and the second part 14 is such that during the rotation of the rotor 10 The fluid moves inward and downward by the first part 13 and outward and downward by the second part 14. This enhances mixing, similar to that described above in the embodiment of FIGS. 15A and 15B. In the embodiment of FIG. 16B, the rotor 10 comprises two arms 11 and two rotor blades 12, and FIG. 16B further shows a flow obstruction 40.

  The stirring devices of FIGS. 11A-B, 12A-D, 13A-B, 14A-B, 15A-B, 16A-B further comprise a drive means, generally at a rotational speed preferably less than 120 revolutions / minute, A motor (not shown) configured to rotate the rotor 10 about the shaft 17 at a rotational speed lower than 30 revolutions / minute, more preferably at a rotational speed of less than 80 revolutions / minute, to ensure even better mixing characteristics. ). Those skilled in the art will also appreciate that two or more motor blades 12, for example three or four motor blades 12, are also options. The optimum rotational speed is further determined by the number and size of the rotor blades 12 and the number and size of the flow obstructions 40.

  The embodiments described above are designed for containers with a cylindrical inner wall. One skilled in the art will appreciate that the design is readily applied to containers with, for example, a conical inner wall. Further, the above-described embodiments have a rotor with at least one arm near the bottom end of the container and below the flow obstruction attached to the cover. One skilled in the art also understands that the arm is positioned above the flow obstruction, in which case the flow obstruction is attached to the bottom of the container.

  A further embodiment of the invention relates to a method of mixing a liquid, in particular a liquid toner, using a stirring device according to any one of the above embodiments. Preferably, the rotor rotates at a relatively low rotational speed, more preferably at a rotational speed of less than 120 revolutions per minute, most preferably between 20 and 100 revolutions per minute.

  The principles of the present invention are set forth above with reference to specific embodiments, and this description is merely an example and is not intended to limit the scope of protection, which is determined by the appended claims.

Claims (15)

A stirring device for stirring a mixture, in particular a liquid containing insoluble particles,
A container containing the mixture;
A rotor comprising a shaft and a rotor blade;
Drive means for rotating the shaft;
At least one flow obstruction between the shaft and the circumferential inner wall of the container,
The flow blocker is fixedly mounted so that the flow blocker is stationary in the container, or the flow blocker rotates at a rotational speed different from the rotational speed of the shaft and / or at a rotational direction different from the rotational direction of the shaft. Is mounted rotatably around the shaft and connected to the drive means,
At least one flow obstruction is located between the shaft and the track followed by the rotor blades of the rotor during operation;
The agitator device, wherein the rotor blade has a shape that directs the mixture inward against at least one flow obstruction. The rotor blade has a first upright elongated portion and a second upright elongated portion,
The first part has an angle with the second part,
The agitation device of claim 1, wherein the mixture moves toward at least one flow blocker during rotation of the rotor. The rotor is an elongated rotor blade having a length direction;
The rotor blade comprises an opening arranged to allow the mixture to pass through at least one opening;
The stirring device according to claim 1, wherein the opening is a slit extending in a length direction.   The agitation device according to any one of claims 1 to 3, wherein the at least one flow inhibitor comprises a flow inhibition plate.   The agitation device according to any one of claims 1 to 4, wherein the at least one flow obstruction is a stator body mounted in a fixed position in the container. The distance between the at least one flow blocker and the rotor shaft is less than 5 cm, preferably less than 3 cm, and / or
Stirring according to any one of the preceding claims, wherein the distance between the at least one flow obstruction and the track followed by the rotor blades of the rotor is less than 5 cm, preferably less than 3 cm, during operation. apparatus.   The stirring device according to any one of claims 1 to 6, wherein the at least one flow obstruction comprises a hollow body comprising at least one measuring device. The rotor blade is fixed to the shaft by means of an arm extending from the shaft in the direction of the circumferential inner wall of the container,
Preferably, the distance between the at least one flow blocker and the region in which the rotor arm rotates is less than 5 cm during operation, more preferably less than 3 cm,
8. The agitation device according to claim 1, wherein the arm preferably comprises an elongated slit extending in the radial direction between the rotor blade and the shaft. The arm includes a first elongated portion and a second elongated portion,
The first and second parts are adjacent parts extending from the shaft in the direction of the circumferential inner wall of the container,
The first part has an angle with the second part,
9. The agitation device of claim 8, wherein the mixture moves toward at least one flow blocker during rotation of the rotor.   The agitation device according to any one of claims 1 to 9, wherein the rotor blade has a shape for directing the mixture upward and / or downward. A rotor blade is an elongated rotor blade that extends at an angle of greater than 90 degrees or less than 90 degrees with respect to a horizontal line tangential to the rotor trajectory when viewing the direction of rotation of the rotor;
11. The agitation device according to claim 10, wherein the rotor blades are tilted at least partially rearward and / or at least partially forward when viewing the direction of rotation of the rotor. The container is a cylindrical container having an inner wall that extends at the distance of the track followed by the rotor blades;
Stirring device according to any one of the preceding claims, wherein the distance is less than 5 cm, preferably less than 3 cm. A printing apparatus comprising a toner supply unit and a toner discharge line;
A stirring device according to any one of claims 1 to 12,
The liquid toner is stored in a container of a stirring device, the container having an outlet and an inlet for discharging the stirred liquid toner;
A printing system, wherein the outlet is connected to a toner supply unit of the printing device and the inlet is connected to a toner discharge line. A reservoir for storing the dispersed substance, the dispersed substance reservoir being connected to the inlet of the container via the dispersed substance dispensing unit;
A reservoir for storing carrier liquid, the carrier liquid reservoir being connected to the inlet of the container via a carrier liquid dosing unit;
23. The agitation device according to any one of claims 1 to 22, wherein the further agitation device container stores a concentrated solution of liquid toner, and the further agitation device container is concentrated. Having an outlet connected to the inlet of a container for storing liquid toner via a solution dispensing unit;
The printing system of claim 13, further comprising at least one of: And a return line for returning the supply reservoir and excess liquid toner to the supply reservoir,
The printing system according to claim 13 or 14, wherein the stirring device is included in the return line.

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