JP2011175210A - Liquid toner-adjusting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid toner-adjusting apparatus that facilitates toner dispersion. <P>SOLUTION: The liquid toner-adjusting apparatus 60 includes a dispersion tank 61, an impeller 65, a stirring tank 67 and an anchor-type impeller 69. Liquid toner T containing a toner and a carrier is guided to the dispersion tank 61. The impeller 65 is provided in the dispersion tank 61 to disperse the aggregated toner contained in the carrier. The liquid toner T in the dispersion tank 61, the toner and the carrier are guided to the stirring tank 67. The anchor-type impeller 69 is provided in the stirring tank 67 to disperse the liquid toner T in the stirring tank 67. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a liquid toner adjusting device that promotes dispersion of toner contained in liquid toner.

  Conventionally, an electrophotographic printing apparatus using liquid toner has been proposed. The liquid toner is a toner in which a solid toner composed of a thermoplastic resin and a pigment (dye) is dispersed in a carrier. As such an electrophotographic printing apparatus, for example, as disclosed in Patent Document 1, there is one that collects liquid toner guided to the developing unit and guides the recovered liquid toner to the developing unit again. However, since the liquid toner collected from the developing unit is agglomerated with solid toner, it is necessary to disperse the toner again. As a technique for this, for example, Patent Document 2 discloses a device that includes a spiral impeller and stirs a carrier and toner.

JP 2009-163064 A JP 2007-94161 A

  The apparatus disclosed in Patent Document 2 only stirs liquid toner. The collected liquid toner is charged and aggregated. Therefore, the toner may not be dispersed only by stirring. Therefore, in the apparatus disclosed in Patent Document 2, the agglomerated toner may be agitated in the carrier while being agglomerated without being dispersed. When the agglomerated toner is guided to the developing unit, the electrophotographic printing apparatus deteriorates the printing quality. As described above, the apparatus disclosed in Patent Document 2 may cause insufficient dispersion of the aggregated toner.

  The present invention has been made in view of the above, and an object thereof is to promote toner dispersion.

  In order to solve the above-described problems and achieve the object, a liquid toner adjusting device according to the present invention includes a dispersion tank into which liquid toner recovered from a developing unit can be guided, and an aggregation included in the liquid toner. A dispersion means capable of dispersing the toner in the dispersion tank, the liquid toner in the dispersion tank, a new liquid toner can be guided, and a stirring tank capable of stirring the liquid toner; It is characterized by providing.

  With the above-described configuration, the liquid toner adjusting device according to the present invention temporarily stores liquid toner containing agglomerated toner in the dispersion tank. The liquid toner adjusting device according to the present invention disperses the aggregated toner by the dispersing means. In this manner, the liquid toner adjusting device according to the present invention sufficiently disperses the agglomerated toner and then guides the liquid toner to the stirring tank. Accordingly, the liquid toner adjusting device according to the present invention can promote the dispersion of the toner.

  As a preferred aspect of the present invention, it is preferable that the liquid toner in the stirring tank is provided with stirring means capable of stirring the liquid toner, and the liquid toner in the stirring tank can be guided to the developing unit.

  With the above configuration, in the liquid toner adjusting device according to the present invention, the stirring means can stir the liquid toner. Thereby, the liquid toner adjusting device according to the present invention can reduce the deviation of the concentration of the liquid toner in the stirring tank. Further, the liquid toner adjusting device according to the present invention can guide the liquid toner in the stirring tank to the developing unit again. Therefore, the liquid toner adjusting device according to the present invention can reuse the liquid toner.

  As a preferred aspect of the present invention, it is desirable that the stirring unit includes an impeller capable of generating a vortex in the liquid toner in the stirring tank.

  With the above configuration, the stirring unit can stir the liquid toner guided from the dispersion tank to the stirring tank by the stirring unit. Thereby, the liquid toner adjusting device according to the present invention can reduce the deviation of the concentration of the liquid toner in the stirring tank.

  As a preferred aspect of the present invention, it is desirable that the dispersing means includes an impeller capable of applying a shearing force to the aggregated toner.

  With the above configuration, the dispersing means can disperse the aggregated toner lump so as to cut it.

  As a preferred aspect of the present invention, it is desirable to provide a bubble collecting means provided in at least one of the dispersion tank and the stirring tank and capable of collecting bubbles contained in the liquid toner.

  With the above configuration, the liquid toner adjusting device according to the present invention can reduce bubbles contained in the liquid toner.

  As a preferred aspect of the present invention, the bubble collecting means includes a partition plate that divides a space for storing the liquid toner, and a communication portion that is provided in the partition plate and communicates the divided spaces. It is desirable to include.

  With the above configuration, in the liquid toner adjusting device according to the present invention, the liquid toner accommodated in one of the plurality of spaces moves to another space via the communication portion. At this time, the bubbles contained in the liquid toner accumulate on the liquid surface side, and thus do not easily pass through the communicating portion. In this way, the partition plate collects bubbles contained in the liquid toner on the liquid surface. Thus, the liquid toner adjusting device according to the present invention can reduce bubbles contained in the liquid toner.

  As a preferred aspect of the present invention, it is desirable that the bubble collecting means includes a porous member.

  The porous member can collect bubbles contained in the liquid toner. Therefore, the liquid toner adjusting device according to the present invention can reduce bubbles contained in the liquid toner.

  As a preferred aspect of the present invention, it is desirable that the dispersing means includes solid particles provided in the dispersing tank and solid particle moving means that allows the solid particles to move in the dispersing tank.

  The solid particles move in the liquid toner by the solid particle moving means. Then, the solid particles collide with the aggregated toner. Thereby, the liquid toner adjusting device according to the present invention can promote the dispersion of the aggregated toner.

  As a preferred aspect of the present invention, it is desirable that the dispersion means includes a sound wave generator capable of transmitting sound waves to the liquid toner in the dispersion tank.

  With the above configuration, the agglomerated toner vibrates. Aggregated toners are separated from each other by vibration. Therefore, the liquid toner adjusting device according to the present invention can promote the dispersion of the aggregated toner.

  The present invention can promote toner dispersion.

FIG. 1 is an explanatory diagram schematically illustrating the electrophotographic printing apparatus according to the first embodiment. FIG. 2 is an explanatory diagram schematically illustrating the liquid toner adjusting device according to the first embodiment. FIG. 3 is an explanatory view schematically showing an impeller type impeller. FIG. 4 is an explanatory view schematically showing a propeller-type impeller. FIG. 5 is an explanatory view schematically showing a pitched paddle type impeller. FIG. 6 is an explanatory view schematically showing a pitched turbine impeller. FIG. 7 is an explanatory view schematically showing a flat turbine impeller. FIG. 8 is an explanatory view schematically showing a screw type impeller. FIG. 9 is an explanatory view schematically showing a spiral impeller. FIG. 10 is an explanatory diagram schematically showing a flat impeller. FIG. 11 is an explanatory view schematically showing a pitched paddle (multi) type impeller. FIG. 12 is an explanatory diagram schematically illustrating a liquid toner adjusting device according to a modification of the first embodiment. FIG. 13 is an explanatory diagram schematically illustrating a liquid toner adjusting device according to the second embodiment.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following description. In addition, constituent elements in the following description include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range.

(Embodiment 1)
The electrophotographic printing apparatus of this embodiment is a liquid development electrophotographic printing machine. The electrophotographic printing apparatus includes a paper feed unit, a printing unit, and a paper discharge unit. The paper feed unit can supply, for example, sheet-by-sheet print sheets one by one from the paper feed tray to the printing unit. The printing unit can perform printing on one side or both sides of the supplied printing sheet. The paper discharge unit can discharge a printed sheet printed on one or both sides by the printing unit to a paper discharge tray.

  FIG. 1 is an explanatory diagram schematically illustrating the electrophotographic printing apparatus according to the first embodiment. Hereinafter, the electrophotographic printing apparatus 10 of this embodiment will be described in detail. As shown in FIG. 1, the printing unit 11 includes an intermediate transfer body 12, a backup roller 13, a plurality (four in this embodiment) of developing units 14 a, 14 b, 14 c, and 14 d, and a liquid toner supply device 20. A cleaning device 30, a liquid toner recovery device 40, and a solid content separation device 50. Although not shown, the printing unit 11 includes a print sheet conveying device, a toner fixing device, and the like. In this case, the printing unit 11 is configured to perform process color printing. The developing units 14a, 14b, 14c, and 14d correspond to the process colors of C (blue), M (red), Y (yellow), and K (black).

  The printing unit 11 performs printing with the liquid toner T. The liquid toner T is a mixture of toner dispersed in a carrier. The toner is in the form of particles formed of a thermoplastic material and a pigment (pigment or dye). The carrier is a petroleum solvent (for example, nonpolar, paraffinic solvent, mineral oil, etc.). The liquid toner T is a toner in which particulate toner having an average particle diameter of about 1 to 2 μm is contained in a carrier at a concentration of about 10 to 40 percent by weight.

  The intermediate transfer member 12 is in contact with the backup roller 13. The intermediate transfer body 12 forms a nip portion (transfer position) N1 at the contact portion. The intermediate transfer body 12 has a blanket 12a wound around an outer peripheral surface. The blanket 12a is made of urethane conductive rubber. The intermediate transfer member 12 has a bias voltage difference from the photosensitive drum 15.

  The backup roller 13 is arranged to apply a pressure to the intermediate transfer body 12 at a predetermined pressure, for example, about 1 to 13 kg / cm. The backup roller 13 forms the above-described nip portion N <b> 1 at the contact portion with the intermediate transfer body 12. For this reason, the print sheet S is conveyed between the intermediate transfer body 12 and the backup roller 13, whereby a predetermined nip pressure is applied. For example, a bias voltage of about −800 V is applied to the backup roller 13. As a result, the printing unit 11 gives the liquid toner T an attractive force from the intermediate transfer body 12 to the backup roller 13 due to the difference between the intermediate transfer body 12 and the bias voltage of the backup roller 13. In this way, the printing unit 11 promotes electrostatic transfer of the liquid toner T from the intermediate transfer body 12 to the print sheet S.

  The developing units 14a, 14b, 14c, and 14d are arranged around the intermediate transfer body 12 along the rotation direction. The developing units 14a, 14b, 14c, and 14d are different in the color of the liquid toner T guided to the intermediate transfer body 12, but the configuration is the same. Therefore, in the following, the developing unit 14a will be described in detail.

  The developing unit 14a includes a photosensitive drum 15, a supply pan 16a, and a liquid toner conveying roller 16b. The photosensitive drum 15 has a photosensitive layer formed on the outer peripheral surface. The photosensitive layer is formed including a photosensitive agent such as amorphous silicon (a-Si) or a photosensitive polymer. The photosensitive drum 15 contacts the intermediate transfer body 12 at the nip portion N2. The supply pan 16a is a container for storing the liquid toner T. The liquid toner transport roller 16 b transports the liquid toner T from the supply pan 16 a to the photosensitive drum 15. With the above configuration, the developing unit 14a can transfer the liquid toner T guided from the supply pan 16a to the outer periphery of the photosensitive drum 15 to the intermediate transfer body 12 by the liquid toner conveying roller 16b.

  The liquid toner supply device 20 includes a concent tank 21, a carrier tank 22, a liquid toner adjusting device 60, a concent pump 25a, a carrier pump 25b, a liquid toner pump 25c, a recovery pump 25d, a recovery pump 25e, A collection blade 26 and a concentration sensor 27 are included. The concentrated tank 21 is a container for storing liquid toner T1 having a higher concentration than the liquid toner T guided to the photosensitive drum 15. When the capacity of the high-concentration liquid toner T1 is insufficient, the concentrated tank 21 is replenished with the high-concentration liquid toner T1 from the bottle toner 21a. The carrier tank 22 is a container for storing carriers. The carrier tank 22 is replenished with carriers from the carrier can 22a when the carrier capacity is insufficient.

  The liquid toner adjusting device 60 includes a dispersion tank 61 and a stirring tank 67. A more detailed configuration of the liquid toner adjusting device 60 will be described later. The dispersion tank 61 is a container for storing the liquid toner T collected from the liquid toner conveying roller 16b. The agitation tank 67 is a container for storing a liquid mixture of the high-concentration liquid toner T1 and the carrier, that is, the liquid toner T. The liquid toner T in the dispersion tank 61 is guided to the stirring tank 67 by overflowing from the dispersion tank 61, for example.

  The concrete pump 25 a is provided in a passage connecting the concrete tank 21 and the agitation tank 67. The concrete pump 25 a guides the high-concentration liquid toner T <b> 1 in the concrete tank 21 to the stirring tank 67. The carrier pump 25 b is provided in a passage connecting the carrier tank 22 and the stirring tank 67. The carrier pump 25 b guides the carrier in the carrier tank 22 to the stirring tank 67. The liquid toner pump 25c is provided in a passage connecting the stirring tank 67 and the supply pan 16a. The liquid toner pump 25c guides the liquid toner T in the stirring tank 67 to the supply pan 16a. The recovery pump 25d is provided in a passage connecting the supply pan 16a and the stirring tank 67. The recovery pump 25d returns the excess liquid toner T in the supply pan 16a to the stirring tank 67.

  The collection blade 26 is in contact with the outer peripheral portion of the liquid toner conveying roller 16b. The collection blade 26 collects excess liquid toner T on the outer peripheral portion of the liquid toner transport roller 16b. The excess liquid toner T here is the liquid toner T that has not been transferred to the outer peripheral portion of the photosensitive drum 15. Specifically, the excess liquid toner T is the liquid toner T in the non-image area on the outer peripheral portion of the liquid toner transport roller 16b. The recovery pump 25 e is provided in a passage that connects the recovery blade 26 and the dispersion tank 61. The recovery pump 25 e guides the liquid toner T recovered by the recovery blade 26 to the dispersion tank 61.

  The concentration sensor 27 is provided, for example, in a passage that connects the stirring tank 67 and the supply pan 16a. The density sensor 27 detects the density of the liquid toner T guided to the supply pan 16a. A control device (not shown) acquires a signal indicating the density of the liquid toner T from the density sensor 27. Then, the control device mixes the high-concentration liquid toner T1 and the carrier so that the concentration of the liquid toner T becomes a predetermined concentration (the weight ratio of the toner and the carrier is, for example, 10 to 40 percent). That is, the control device controls the operation of the concentric pump 25a and the operation of the carrier pump 25b.

  The conc tank 21, the dispersion tank 61, the agitation tank 67, the conc pump 25a, the liquid toner pump 25c, the recovery pump 25d, the recovery pump 25e, the recovery blade 26, and the concentration sensor 27 are each developed. One is provided for each developing unit of the units 14a, 14b, 14c, and 14d. The carrier tank 22 and the carrier pump 25b are shared by each developing unit. The carrier pump 25b guides the carrier from the carrier tank 22 to the stirring tank 67 for each developing unit. One carrier tank 22 and one carrier pump 25b may be provided for each developing unit. With the above configuration, the liquid toner supply device 20 guides the liquid toner T to the outer peripheral portion of the photosensitive drum 15.

  The cleaning device 30 includes a carrier nozzle 31, a carrier pump 32, a first cleaning roller 33a, a second cleaning roller 33b, a collection blade 34a, a collection blade 34b, and a collection blade 34c. The carrier nozzle 31 is provided to face the outer peripheral portion of the intermediate transfer body 12. Specifically, the carrier nozzle 31 is provided between the nip portion N1 of the intermediate transfer member 12 and the backup roller 13 and the nip portion N2 of the intermediate transfer member 12 and the photosensitive drum 15 for the first color. The carrier nozzle 31 discharges the carrier and guides the carrier to the outer peripheral portion of the intermediate transfer body 12.

  The carrier pump 32 is provided in a passage connecting the carrier tank 22 and the carrier nozzle 31. The carrier pump 32 guides the carrier in the carrier tank 22 to the carrier nozzle 31. The first cleaning roller 33 a and the second cleaning roller 33 b are provided in contact with the outer peripheral portion of the intermediate transfer body 12. The first cleaning roller 33a is provided between the photosensitive drum 15 of the developing unit 14b and the photosensitive drum 15 of the developing unit 14c. The second cleaning roller 33b is provided between the photosensitive drum 15 of the developing unit 14d and the backup roller 13. The first cleaning roller 33 a and the second cleaning roller 33 b come into contact with the intermediate transfer body 12 during printing on the print sheet S, and collect a part of the liquid toner T on the outer peripheral portion of the intermediate transfer body 12. Accordingly, the first cleaning roller 33a and the second cleaning roller 33b prepare the liquid toner T on the outer peripheral portion of the intermediate transfer body 12.

  The collection blade 34a is provided to face the outer periphery of the first cleaning roller 33a. The collection blade 34a collects the liquid toner T on the outer periphery of the first cleaning roller 33a. The collection blade 34b is provided to face the outer peripheral portion of the second cleaning roller 33b. The collection blade 34b collects the liquid toner T on the outer periphery of the second cleaning roller 33b. The collection blade 34 c is provided to face the outer peripheral portion of the intermediate transfer body 12. Specifically, the collection blade 34c is provided between the carrier nozzle 31 and the photosensitive drum 15 of the developing unit 14a. The collection blade 34c collects the liquid toner T diluted by the carrier discharged from the carrier nozzle 31.

  The liquid toner recovery device 40 includes a liquid toner recovery pump 41a, a liquid toner recovery pump 41b, and a liquid toner recovery pump 41c. The liquid toner recovery pump 41a is provided in a path connecting the recovery blade 34c and the solid content separation device 50. The solid content separation device 50 promotes the separation of the toner as the solid content contained in the guided liquid toner T and the carrier, and collects the liquid toner T (mainly the carrier) in which the contained toner is reduced. It is. The solid content separation device 50 includes, for example, a filter capable of collecting the toner and allowing the carrier to pass therethrough.

  The liquid toner recovery pump 41a guides the liquid toner T recovered by the recovery blade 34c to the solid content separation device 50. The liquid toner recovery pump 41b is provided in a path connecting the recovery blade 34a and the solid content separation device 50. The liquid toner recovery pump 41 b guides the liquid toner T recovered by the recovery blade 34 a to the solid content separation device 50. The liquid toner recovery pump 41 c is provided in a path connecting the recovery blade 34 b and the solid content separation device 50. The liquid toner recovery pump 41 c guides the liquid toner T recovered by the recovery blade 34 b to the solid content separation device 50.

  Here, the electrophotographic printing apparatus 10 of the present embodiment shown in FIG. 1 reuses the carrier in which the toner contained is reduced by the solid content separation apparatus 50. As a configuration for this purpose, the electrophotographic printing apparatus 10 includes a recycle carrier supply pump 17. The recycle carrier supply pump 17 is provided in a passage connecting the solid content separation device 50 and the carrier tank 22. In the present embodiment, the recycled carrier supply pump 17 is provided between the solid content separation device 50 and the carrier tank 22. Thereby, the recycled carrier supply pump 17 guides the carrier in which the contained toner is reduced by the solid content separation device 50 to the carrier tank 22. Next, a more detailed configuration of the liquid toner adjusting device 60 will be described in detail.

  FIG. 2 is an explanatory diagram schematically illustrating the liquid toner adjusting device according to the first embodiment. As shown in FIG. 2, the liquid toner adjusting device 60 includes a dispersion tank 61, a partition plate 62 as a bubble collecting means, a porous member 63 as a bubble collecting means, a dispersing motor 64, and a dispersing means. The impeller type impeller 65, the discharge part 66, the stirring tank 67, the stirring motor 68, the anchor type impeller 69 as a stirring means, and the cooling device 70 are included. As described above, the dispersion tank 61 is a tank to which the liquid toner T collected from the liquid toner conveyance roller 16b is guided. That is, the agglomerated toner is guided to the dispersion tank 61.

  The partition plate 62 partitions a space inside the dispersion tank 61, that is, a space for storing the liquid toner T into a plurality of spaces. The partition plate 62 is provided along the vertical direction, and divides the space inside the dispersion tank 61 into a plurality of portions in the horizontal direction. In addition, if the partition plate 62 is the structure which can divide | segment the space inside the dispersion | distribution tank 61 into multiple in a horizontal direction, you may be inclined and provided with respect to a perpendicular direction. For example, one partition plate 62 according to the present embodiment is provided, and divides the space in the dispersion tank 61 into a space A1 and a space A2.

  The partition plate 62 includes a communication part 62c as a bubble collecting means. The communicating part 62c is a part that communicates the space A1 and the space A2. Here, the surface on the lower side in the vertical direction of the dispersion tank 61 is defined as a bottom surface 61a. Moreover, let the part which opposes the bottom face 61a among the partition plates 62 be the lower end part 62a, and let the opposite side in the perpendicular direction to the lower end part 62a be the upper end part 62b. The partition plate 62 is provided so that the upper end portion 62 b protrudes upward in the vertical direction from the liquid level M of the liquid toner T in the dispersion tank 61. Further, the partition plate 62 is provided with a gap between the lower end portion 62a and the bottom surface 61a. In the present embodiment, the gap functions as the communication portion 62c.

  The partition plate 62 may be provided without ensuring a gap between the lower end portion 62a and the bottom surface 61a. In this case, the communication part 62 c is formed as a hole on the lower end part 62 a side of the partition plate 62. In addition, the site | part in which the communication part 62c is formed is not limited to the lower end part 62a side. The communication part 62c may be provided in the center part of the partition plate 62 in the vertical direction, or may be provided on the upper end part 62b side with respect to the center part. However, the communication part 62 c is formed on the lower end part 62 a side with respect to the liquid level M in the dispersion tank 61. The communication part 62c is a part for suppressing air bubbles contained in the liquid toner T in the dispersion tank 61 from going back and forth between the space A1 and the space A2. Therefore, it is preferable that the communication part 62c is formed in a part of the partition plate 62 where bubbles contained in the liquid toner T are difficult to reach. Therefore, the part where the communication part 62c is formed is more preferable as it approaches the lower end part 62a side, which is the lower side in the vertical direction.

  The porous member 63 is, for example, a metal or synthetic resin mesh. However, the material constituting the porous member 63 is not limited. Further, the porous member 63 may be, for example, a plate-like member in which a plurality of holes are formed or a cloth-like member. That is, the porous member 63 may be any member that can collect bubbles contained in the liquid toner T and can pass through the toner and carrier contained in the liquid toner T. The porous member 63 is provided in the space A1. The porous member 63 is provided so that the liquid toner T guided to the space A1 passes therethrough. The porous member 63 is provided between the upper end portion 62b and the communication portion 62c (the lower end portion 62a in the present embodiment). In the present embodiment, the porous member 63 is provided on the upper end 62b side (that is, the entrance of the space A1) from the liquid level M in the dispersion tank 61.

  The dispersing motor 64 is, for example, a device that generates rotational force when supplied with electricity. The dispersing motor 64 may be, for example, a device that generates a rotational force when a fluid such as air or liquid is guided. The dispersion motor 64 is attached to the dispersion tank 61 by a support body 64a, for example. The dispersion motor 64 may not be attached to the dispersion tank 61, and may be supported by the support body 64a on the frame of the electrophotographic printing apparatus 10, for example.

  FIG. 3 is an explanatory view schematically showing an impeller type impeller. An impeller type impeller 65 shown in FIG. 3 is an impeller that can apply a shearing force to the agglomerated toner in the dispersion tank 61. The impeller-type impeller 65 has, for example, a shape in which a blade is formed on the periphery of a disk-shaped base. The impeller-type impeller 65 rotates by obtaining a rotational force from the dispersing motor 64 shown in FIG. The impeller type impeller 65 is not an impeller intended to generate a vortex in the liquid toner T in the dispersion tank 61, but an impeller intended to disperse the toner by tearing a lump of aggregated toner. It is. The impeller type impeller 65 is provided in the space A2 shown in FIG. The rotation axis of the impeller type impeller 65 of the present embodiment is, for example, along the vertical direction. However, the rotation shaft of the impeller type impeller 65 may be inclined with respect to the vertical direction or may be along the horizontal direction.

  FIG. 4 is an explanatory view schematically showing a propeller-type impeller. FIG. 5 is an explanatory view schematically showing a pitched paddle type impeller. FIG. 6 is an explanatory view schematically showing a pitched turbine impeller. FIG. 7 is an explanatory view schematically showing a flat turbine impeller. The liquid toner adjusting device 60 of the present embodiment replaces the impeller type impeller 65 shown in FIG. 3 as a dispersing means, such as a propeller type impeller 65A shown in FIG. 4, a pitched paddle type impeller 65B shown in FIG. A pitched turbine impeller 65C shown in FIG. 6 or a flat turbine impeller 65D shown in FIG. 7 may be provided. Even in these impellers, each dispersing means can disperse the agglomerated toner.

  The discharge part 66 shown in FIG. 2 is formed in the dispersion tank 61. The discharge unit 66 communicates the space A <b> 2 and the outside of the dispersion tank 61. The discharge part 66 is a hole, for example. However, the discharge part 66 is not limited to a hole, and may be a notch formed in the upper opening 61b of the dispersion tank 61, for example. The discharge part 66 of the present embodiment is formed on the upper side in the vertical direction of the dispersion tank 61 (on the upper opening 61b side of the dispersion tank 61). In addition, the site | part in which the discharge part 66 is formed is not limited to the vertical direction upper side among the dispersion tanks 61, For example, you may provide in the center part in the vertical direction of the dispersion tank 61. However, the height of the liquid level M (distance from the bottom surface 61 a) decreases as the part where the discharge portion 66 is formed approaches the bottom surface 61 a, that is, the liquid toner T that can be stored in the dispersion tank 61. The liquid volume decreases. Therefore, the discharge part 66 is preferably formed on the upper opening 61b side. Thereby, the dispersion tank 61 can store more liquid toner T.

  The stirring tank 67 is provided at a position where the liquid toner T in the dispersion tank 61 can be guided through the discharge unit 66. The liquid toner adjusting device 60 of this embodiment guides the liquid toner T from the dispersion tank 61 to the stirring tank 67 by gravity. Therefore, the stirring tank 67 is disposed directly below the dispersion tank 61 in the vertical direction. The liquid toner adjusting device 60 guides the liquid toner T to the stirring tank 67 by causing the liquid toner T to overflow from the discharge portion 66. The liquid toner adjusting device 60 may have a passage connecting the discharge unit 66 and the stirring tank 67. In this case, the agitation tank 67 does not need to be disposed directly below the dispersion tank 61 in the vertical direction, and may be disposed obliquely below, for example, as long as it is below the dispersion tank 61 in the vertical direction.

  In addition, the liquid toner adjusting device 60 may guide the liquid toner T from the discharge unit 66 to the stirring tank 67 by a pump. In this case, the agitation tank 67 may be disposed at the same height as the dispersion tank 61 or on the upper side in the vertical direction from the dispersion tank 61. However, it is preferable that the stirring tank 67 is disposed directly above the dispersion tank 61 in the vertical direction. Thereby, the liquid toner adjusting device 60 can omit a passage (pipe) or a component such as a pump.

  The stirring motor 68 is, for example, a device that generates rotational force when supplied with electricity. The stirring motor 68 may be, for example, a device that generates a rotational force when a fluid such as air or liquid is guided. The stirring motor 68 is attached to the stirring tank 67 by a support 68a, for example. The stirring motor 68 may not be attached to the stirring tank 67, and may be supported by the support 68a on the frame of the electrophotographic printing apparatus 10, for example.

  The anchor type impeller 69 is an impeller capable of generating a vortex in the liquid toner T in the stirring tank 67. The anchor type impeller 69 rotates by obtaining a rotational force from the stirring motor 68 shown in FIG. The anchor type impeller 69 is not an impeller intended to disperse the toner by cutting the aggregated toner lump. Therefore, the anchor type impeller 69 is formed to have a larger area that can apply force to the liquid toner T than the impeller type impeller 65. Specifically, the anchor type impeller 69 is formed larger than the impeller type impeller 65. The shape of the anchor type impeller 69 includes a portion 69a orthogonal to the rotation axis of itself (anchor type impeller 69) and a portion 69b parallel to the rotation axis. The anchor type impeller 69 may rotate at a lower speed than the stirring motor 68. In this embodiment, the stirring motor 68 rotates at, for example, 200 rpm, while the anchor type impeller 69 rotates at, for example, 100 rpm.

  FIG. 8 is an explanatory view schematically showing a screw type impeller. FIG. 9 is an explanatory view schematically showing a spiral impeller. FIG. 10 is an explanatory diagram schematically showing a flat impeller. FIG. 11 is an explanatory view schematically showing a pitched paddle (multi) type impeller. The liquid toner adjusting device 60 of the present embodiment replaces the anchor type impeller 69 shown in FIG. 2 as a dispersing means, as a screw type impeller 69A shown in FIG. 8, a spiral type impeller 69B shown in FIG. A flat plate type impeller 69C shown in FIG. 10 or a pitched paddle (multi) type impeller 69D shown in FIG. 11 may be provided. Even in these impellers, each dispersing means can disperse the agglomerated toner.

  The cooling device 70 illustrated in FIG. 2 is provided in the stirring tank 67. The cooling device 70 is, for example, a Peltier element. The cooling device 70 moves the heat of the liquid toner T in the stirring tank 67 to the outside by being supplied with electric power. Thereby, the cooling device 70 cools the liquid toner T in the stirring tank 67. Here, the cooling device 70 is electrically connected to a control device (not shown), and the amount of power supplied by the control device and the timing at which the power is supplied are adjusted. Thereby, the cooling device 70 adjusts the liquid toner T in the stirring tank 67 to an appropriate temperature. Note that the liquid toner adjusting device 60 may not include the cooling device 70 when it is not necessary to adjust the temperature of the liquid toner T in the stirring tank 67. Next, a mechanism by which the liquid toner adjusting device 60 promotes toner dispersion will be described.

  The liquid toner T collected from the liquid toner conveying roller 16b shown in FIG. 1 is guided to the space A1 of the dispersion tank 61 through the porous member 63 shown in FIG. At this time, the porous member 63 collects bubbles contained in the liquid toner T. Therefore, the liquid toner adjusting device 60 can reduce bubbles contained in the liquid toner T guided to the space A1. The liquid toner T in the space A1 moves to the space A2 via the communication part 62c. At this time, since the air bubbles that have passed through the porous member 63 accumulate on the liquid surface M side, it is difficult for the air bubbles to pass through the communication portion 62c. In this way, the partition plate 62 collects bubbles contained in the liquid toner T in the space A1 on the liquid level M. Thereby, the liquid toner adjusting device 60 can reduce bubbles that move to the space A2 via the communication portion 62c. As a result, the liquid toner adjusting device 60 can suppress a decrease in print quality of the electrophotographic printing apparatus 10 due to bubbles contained in the liquid toner T.

  Aggregated toner contained in the liquid toner T guided to the space A <b> 2 is dispersed by the impeller type impeller 65. The liquid toner T in which the toner is dispersed by the impeller type impeller 65 is guided to the agitation tank 67 through the discharge unit 66. As described above, the liquid toner adjusting device 60 temporarily accumulates the liquid toner T collected from the liquid toner conveying roller 16 b in the dispersion tank 61 and disperses the aggregated toner by the impeller impeller 65. Then, the liquid toner adjusting device 60 guides the liquid toner T to the stirring tank 67 through the discharge unit 66 after sufficiently dispersing the aggregated toner. Thereby, the liquid toner adjusting device 60 can promote the dispersion of the toner.

  Here, the distance between the portion where the liquid toner T is guided to the dispersion tank 61 (the portion where the porous member 63 is provided in the present embodiment) and the discharge portion 66 is preferably as large as possible. In the present embodiment, the discharge portion 66 is formed on the opposite side in the horizontal direction from the portion where the liquid toner T is guided to the dispersion tank 61 (the portion where the porous member 63 is provided in the present embodiment). Thereby, the liquid toner adjusting device 60 can increase the path of the liquid toner T from being guided to the dispersion tank 61 until being discharged from the discharge portion 66. As a result, the liquid toner adjusting device 60 can reduce the possibility that the liquid toner T is guided to the stirring tank 67 through the discharge portion 66 while the toner is not sufficiently dispersed by the impeller type impeller 65.

  Further, the liquid toner T guided from the dispersion tank 61 to the stirring tank 67 is stirred by the anchor-type impeller 69 together with the high-concentration liquid toner T1 guided from the conc tank 21 and the carrier guided from the carrier tank 22. Is done. Thereby, the liquid toner adjusting device 60 can reduce the unevenness of the concentration of the liquid toner T in the stirring tank 67. As a result, the liquid toner adjusting device 60 can suppress a decrease in the print quality of the electrophotographic printing apparatus 10 due to the uneven density of the liquid toner T.

  Here, although the impeller type impeller 65 is superior in function, the stirring tank 67 also has a function of promoting the dispersion of the toner contained in the liquid toner T. Therefore, the liquid toner adjusting device 60 has two impeller-type impellers 65 and anchor-type impellers 69, so that it is possible to favorably promote toner dispersion. In order to further promote toner dispersion, the liquid toner adjusting device 60 preferably has an impeller equivalent to the impeller type impeller 65 in the stirring tank 67 coaxially with the anchor type impeller 69. Thereby, the liquid toner adjusting device 60 can further favorably promote the dispersion of the toner contained in the liquid toner T in the stirring tank 67. However, even if the liquid toner adjusting device 60 does not include an impeller equivalent to the impeller-type impeller 65 in the stirring tank 67, the toner dispersion can be promoted with sufficient accuracy to withstand practical use.

  The liquid toner adjusting device 60 may not include the bubble collecting means (partition plate 62 and communication portion 62c or porous member 63). Depending on the configuration of the electrophotographic printing apparatus 10, the liquid toner T collected from the liquid toner conveying roller 16b may not include bubbles. In this case, the liquid toner adjusting device 60 can suppress the deterioration of the printing quality of the electrophotographic printing apparatus 10 without including the bubble collecting means. However, for example, when the liquid toner T collected by the collection blade 26 is collected with a brush, the liquid toner T collected from the liquid toner transport roller 16b tends to contain bubbles. In such a case, the liquid toner adjusting device 60 is preferably provided with a bubble collecting means. Thereby, the liquid toner adjusting device 60 can suppress a decrease in print quality of the electrophotographic printing apparatus 10 caused by bubbles contained in the liquid toner T.

  Further, the bubble collecting means may be provided in the stirring tank 67. In this case, the porous member 63 is provided in the upper opening 67b of the stirring tank 67, for example. As a result, the liquid toner T overflowing from the discharge portion 66 toward the stirring tank 67 passes through the porous member 63 and is guided to the stirring tank 67. Further, the partition plate 62 divides the space in the stirring tank 67 into a plurality of spaces. The communication portion 62 c is formed on the bottom surface 67 a side of the stirring tank 67 in the partition plate 62. In this case, in the liquid toner adjusting device 60, the anchor type impeller 69 is disposed in one of the plurality of spaces of the stirring tank 67, and the liquid toner T is supplied from the dispersion tank 61 to the space where the anchor type impeller 69 is not disposed. Supplied. Even in these cases, the liquid toner adjusting device 60 can reduce bubbles contained in the liquid toner T guided to the supply pan 16a shown in FIG. The bubble collecting means may be provided in both the dispersion tank 61 and the stirring tank 67. In this case, the liquid toner adjusting device 60 can more suitably reduce bubbles contained in the liquid toner T guided to the supply pan 16a.

  Further, when the bubble collecting means is provided, the liquid toner adjusting device 60 may include at least one of the partition plate 62 and the communication portion 62 c and the porous member 63. The liquid toner adjusting device 60 can reduce bubbles contained in the liquid toner T only by including the partition plate 62 and the communication portion 62c. Further, the liquid toner adjusting device 60 can reduce bubbles contained in the liquid toner T only by including the porous member 63. However, the liquid toner adjusting device 60 can more appropriately reduce the bubbles contained in the liquid toner T if it includes both the partition plate 62 and the communication portion 62 c and the porous member 63.

  In this embodiment, the partition plate 62 is provided so as to divide the space in the dispersion tank 61 into two in the horizontal direction, but is provided so as to divide the space in the dispersion tank 61 into a plurality in the vertical direction. Also good. In this case, the impeller type impeller 65 is provided in the space below the vertical direction among the plurality of spaces of the dispersion tank 61. In addition, the discharge unit 66 is provided in a space on the lower side in the vertical direction among the plurality of spaces of the dispersion tank 61. Even in this case, the liquid toner adjusting device 60 can reduce the risk that bubbles contained in the liquid toner T are guided to the space on the side where the impeller type impeller 65 is provided. Hereinafter, an example of the liquid toner adjusting device 60 in a mode in which the space in the dispersion tank 61 is divided into a plurality of parts in the vertical direction (more precisely, the space in the dispersion tank 61 is also divided in the horizontal direction) will be described.

(Modification)
FIG. 12 is an explanatory diagram schematically illustrating a liquid toner adjusting device according to a modification of the first embodiment. A liquid toner adjusting device 60 </ b> A of this modification shown in FIG. 12 includes an inner dispersion tank 71, an outer dispersion tank 72, a communication portion 73, a horizontal passage 74, and a vertical passage 75. The inner dispersion tank 71 is formed in a shape including a bottom surface 71a and a peripheral surface 71b. The outer dispersion tank 72 is formed in a shape including a bottom surface 72a and a peripheral surface 72b. The inner dispersion tank 71 is housed inside the outer dispersion tank 72.

  In the liquid toner adjusting device 60 </ b> A, a gap is formed between the bottom surface 71 a of the inner dispersion tank 71 and the bottom surface 72 a of the outer dispersion tank 72. In the liquid toner adjusting device 60 </ b> A, this gap functions as a horizontal passage 74. The impeller type impeller 65 of the present embodiment is provided in the horizontal passage 74. For example, the horizontal passage 74 is formed so that the vertical dimension (the dimension between the bottom surface 71 a and the bottom surface 72 a) is substantially the same (slightly larger) than the vertical dimension of the impeller type impeller 65. In the liquid toner adjusting device 60 </ b> A, a gap is formed between the peripheral surface 71 b of the inner dispersion tank 71 and the peripheral surface 72 b of the outer dispersion tank 72. This gap functions as the vertical passage 75. Thus, in the liquid toner adjusting device 60A, the space A1 is formed inside the inner dispersion tank 71. In the liquid toner adjusting device 60 </ b> A, a space A <b> 2 is formed between the inner dispersion tank 71 and the outer dispersion tank 72.

  The communication portion 73 is formed on the bottom surface 71 a of the inner dispersion tank 71. The communication part 73 is a hole. The communication portion 73 is formed to be larger than the rotating shaft that connects the dispersing motor 64 and the impeller type impeller 65. In the liquid toner adjusting device 60 </ b> A, the gap between the rotation shaft and the hole functions as the communication portion 73. The discharge part 66 of the present embodiment is formed in a portion facing the vertical passage 75.

  Also in the liquid toner adjusting device 60A having the above-described configuration, bubbles contained in the liquid toner T in the space A1 are difficult to move to the space A2 via the communication portion 73 for the same reason as the liquid toner adjusting device 60 shown in FIG. Therefore, the liquid toner adjusting device 60A can reduce bubbles contained in the liquid toner T. Further, the horizontal passage 74 of the present modification is formed so that the vertical dimension is substantially the same as the vertical dimension of the impeller type impeller 65. Therefore, the liquid toner T guided to the space A <b> 2 through the communication portion 73 flows through the horizontal passage 74 while being given a shearing force by the impeller type impeller 65. Therefore, the liquid toner adjusting device 60 </ b> A can reduce the amount of the liquid toner T that is discharged from the discharge unit 66 without being applied with the shearing force by the impeller type impeller 65. As a result, the liquid toner adjusting device 60A can favorably promote the dispersion of the aggregated toner.

(Embodiment 2)
FIG. 13 is an explanatory diagram schematically illustrating a liquid toner adjusting device according to the second embodiment. The liquid toner adjusting device 80 of this embodiment shown in FIG. 13 includes a different dispersion unit from the liquid toner adjusting device 60 shown in FIG. Hereinafter, the same elements as those included in the liquid toner adjusting device 60 are denoted by the same reference numerals. The liquid toner adjusting device 80 includes a solid particle 81 as a dispersing unit, an impeller type impeller 82, an anchor type impeller 83 as a solid particle moving unit, a filter 84, and a sound wave generator 85 as a dispersing unit. Including. In the present embodiment, a case where the bubble collecting means (the partition plate 62 and the communication portion 62c and the porous member 63 shown in FIG. 2) is not provided will be described. However, the liquid toner adjusting device 80 uses the bubble collecting means. You may prepare.

  For example, a plurality of solid particles 81 are arranged inside the dispersion tank 61. The solid particles 81 are arranged so as to flow together with the liquid toner T in the dispersion tank 61. The solid particles 81 are, for example, a lump made of metal or synthetic resin. The shape of the solid particles 81 may be spherical or a shape having corners. The impeller type impeller 82 is an impeller corresponding to the impeller type impeller 65 shown in FIG. The liquid toner adjusting device 80 is replaced with the impeller type impeller 82, the propeller type impeller 65A shown in FIG. 4, the pitched paddle type impeller 65B shown in FIG. 5, and the pitched turbine type impeller shown in FIG. You may provide 65C and the flat turbine type impeller 65D shown in FIG.

  The anchor type impeller 83 is an impeller corresponding to the anchor type impeller 69 shown in FIG. The anchor type impeller 83 generates a vortex in the liquid toner T in the dispersion tank 61 to move the solid particles 81. The liquid toner adjusting device 80 is replaced with the anchor type impeller 83, the screw type impeller 69A shown in FIG. 8, the spiral type impeller 69B shown in FIG. 9, the flat plate type impeller 69C shown in FIG. A pitched paddle (multi-type) impeller 69D shown in FIG. 11 may be provided. The impeller-type impeller 82 and the anchor-type impeller 83 are rotated by obtaining a rotational force from the dispersing motor 64. In the present embodiment, the impeller-type impeller 82 and the anchor-type impeller 83 rotate on the same axis. The impeller-type impeller 82 and the anchor-type impeller 83 may each rotate about separate rotation axes by obtaining rotational force from separate motors.

  The filter 84 is provided in the discharge part 66, for example. The discharge unit 66 can collect the solid particles 81 and can pass the liquid toner T. The sound wave generator 85 generates ultrasonic waves. The sound wave generator 85 is attached to the dispersion tank 61. Thereby, the sound wave generator 85 transmits the ultrasonic wave to the liquid toner T in the dispersion tank 61 via the dispersion tank 61. Note that the sound wave generator 85 may be provided inside the dispersion tank 61 and transmit the ultrasonic waves directly to the liquid toner T. Further, the sound wave generated by the sound wave generator 85 is not limited to the ultrasonic wave. The sound wave generator 85 may generate sound waves having a frequency that can disperse the agglomerated toner. Next, a mechanism by which the liquid toner adjusting device 80 promotes toner dispersion will be described.

  When the anchor type impeller 83 rotates, the liquid toner T in the dispersion tank 61 generates a vortex. Thereby, the solid particles 81 move in the liquid toner T. Then, the plurality of solid particles 81 collide with the aggregated toner. Thereby, the liquid toner adjusting device 80 can promote the dispersion of the aggregated toner. Further, the liquid toner adjusting device 80 can also promote the dispersion of the aggregated toner by the impeller type impeller 82. Further, the filter 84 can collect the solid particles 81 that are about to flow out of the dispersion tank 61 via the discharge part 66. Thereby, the liquid toner adjusting device 80 can reduce the possibility that the solid particles 81 are guided to the stirring tank 67.

  The sound wave generator 85 transmits sound waves (ultrasonic waves in the present embodiment) to the liquid toner T in the dispersion tank 61. Thereby, the aggregated toner vibrates. Aggregated toners are separated from each other by vibration. Therefore, the liquid toner adjusting device 80 can promote the dispersion of the aggregated toner. As described above, the liquid toner adjusting device 80 can promote the dispersion of the aggregated toner.

  Here, the liquid toner adjusting device 80 may not include the impeller type impeller 82. If the liquid toner adjusting device 80 includes the solid particles 81, the anchor type impeller 83, and the sound wave generating device 85, the dispersion of the aggregated toner can be promoted. However, the liquid toner adjusting device 80 can more preferably promote the dispersion of the aggregated toner when the impeller type impeller 82 is provided. Further, the liquid toner adjusting device 80 may include at least one of the solid particles 81, the anchor type impeller 83, and the sound wave generating device 85. If the liquid toner adjusting device 80 includes the solid particles 81 and the anchor type impeller 83 or the sound wave generating device 85, the dispersion of the aggregated toner can be promoted. However, the liquid toner adjusting device 80 preferably includes both the solid particles 81 and the anchor type impeller 83 and the sound wave generating device 85. Thereby, the liquid toner adjusting device 80 can more preferably promote the dispersion of the aggregated toner.

  In the liquid toner adjusting device 80, dispersing means (impeller type impeller 82, solid particle 81 and anchor type impeller 83, sound wave generator 85) may be provided also in the stirring tank 67. Thereby, the liquid toner adjusting device 80 can also promote the dispersion of the toner contained in the liquid toner T in the stirring tank 67.

  As described above, the liquid toner adjusting device according to the present invention is useful for an electrophotographic printing apparatus that can collect and reuse the liquid toner guided to the liquid toner conveying roller, and particularly promotes dispersion of the toner. Suitable for that.

DESCRIPTION OF SYMBOLS 10 Electrophotographic printing apparatus 11 Printing part 12 Intermediate transfer body 12a Blanket 13 Backup roller 14a, 14b, 14c, 14d Development unit 15 Photosensitive drum 16a Supply pan 16b Liquid toner conveyance roller 17 Recycle carrier supply pump 20 Liquid toner supply apparatus 21 21a Bottle toner 22 Carrier tank 22a Carrier can 25a Concent pump 25b, 32 Carrier pump 25c Liquid toner pump 25d, 25e Collection pump 26, 34a, 34b, 34c Collection blade 27 Concentration sensor 30 Cleaning device 31 Carrier nozzle 33a First cleaning roller 33b Second cleaning roller 40 Liquid toner recovery device 41a, 41b, 41c Liquid toner recovery pump 50 Solid content separation device 60, 0A, 80 liquid toner conditioning apparatus 61 dispersion tank 61a, 67a, 71a, 72a bottom 61b, 67b upper opening 62 partition plate (bubble collecting means)
62a lower end 62b upper end 62c, 73 communicating part (bubble collecting means)
63 porous member (bubble collecting means)
64 Dispersion motor 64a, 68a Support body 65, 82 Impeller type impeller (dispersing means)
66 Discharge part 67 Stirring tank 68 Stirring motor 69 Anchor type impeller (stirring means)
69a, 69b portion 70 cooling device 71 inner dispersion tank 71b, 72b peripheral surface 72 outer dispersion tank 74 horizontal passage 75 vertical passage 81 solid particles (dispersing means)
83 Anchor type impeller (solid particle moving means)
84 Filter 85 Sound wave generator (dispersing means)
A1, A2 Space M Liquid level N1, N2 Nip S Print sheet T Liquid toner T1 High density liquid toner

Claims (9)

A dispersion tank into which liquid toner recovered from the developing unit can be guided;
Dispersion means capable of dispersing the agglomerated toner contained in the liquid toner in the dispersion tank;
An agitation tank capable of guiding the liquid toner in the dispersion tank and new liquid toner and capable of agitating the liquid toner;
A liquid toner adjusting device comprising:   The liquid according to claim 1, further comprising a stirring unit capable of stirring the liquid toner in the stirring tank, wherein the liquid toner in the stirring tank can be guided to the developing unit. Toner adjustment device.   The liquid toner adjusting device according to claim 2, wherein the agitation unit includes an impeller capable of generating a vortex in the liquid toner in the agitation tank.   4. The liquid toner adjusting device according to claim 1, wherein the dispersing unit includes an impeller capable of applying a shearing force to the aggregated toner. 5.   5. The apparatus according to claim 1, further comprising bubble collection means provided in at least one of the dispersion tank and the stirring tank and capable of collecting bubbles contained in the liquid toner. The liquid toner adjusting device according to claim 1. The bubble collecting means is
A partition plate that divides a space for storing the liquid toner;
A communication portion provided on the partition plate and communicating the divided spaces;
The liquid toner adjusting device according to claim 5, comprising:   The liquid toner adjusting device according to claim 5, wherein the bubble collecting unit includes a porous member. The dispersing means includes
Solid particles provided in the dispersion tank;
Solid particle moving means for moving the solid particles in the dispersion tank;
The liquid toner adjusting device according to any one of claims 1 to 7, further comprising: The dispersing means includes
The liquid toner adjusting apparatus according to claim 1, further comprising a sound wave generator capable of transmitting sound waves to the liquid toner in the dispersion tank.

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