JP2011095442A - Extraction device and image forming apparatus in which the extraction device is incorporated - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an extraction device that adequately extracts a dispersant to a dispersoid which is not uniform in concentration, and to provide an image forming apparatus in which the extraction device is formed. <P>SOLUTION: The extraction device includes: a liquid tank which accommodates a liquid sample containing the dispersant and the dispersoid; a conveyance part and a separation part which convey the liquid sample; an extraction part which receives the liquid sample from the separation part; a first collection part which collects the liquid sample from the extraction part; a first pipe line which extends between the first collection part and the liquid tank; a second pipe line which extends outward from the collection part; an exchange part which is formed so that it may exchange the first flow of the liquid sample, which flows in the first pipe line, for the second flow of the liquid sample, which flows in the second pipe line; and a control part which controls the exchanging operation made by the exchange part. In addition, the separation part includes: a first face on which the liquid sample is conveyed toward the extraction part; and an charger which applies a voltage to the liquid sample on the first face to charge the dispersoid. In this case, the first face is charged in reverse polarity to the voltage applied by the charger. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an extraction apparatus for extracting a dispersion medium from a liquid sample and an image forming apparatus incorporating the extraction apparatus.

  A technique for executing a predetermined process using a liquid carried on one surface is used in many fields such as a printing technique. For example, such a technique is applied to an image forming apparatus using a liquid developer (for example, a copier, a printer, a facsimile, or a multifunction machine having these functions).

  The liquid used for processing often contains a dispersion medium and a dispersoid. For example, the above-described image forming apparatus uses toner as a dispersoid and a carrier liquid as a dispersion medium. The dispersion medium plays a role of, for example, promoting uniformity of dispersion of the dispersoid and performing uniform and / or stable processing. In certain processes, it may be desired to recover and reuse the dispersion medium.

  Patent Document 1 discloses a recycling apparatus for recovering a dispersion medium. This recycling apparatus includes two members spaced apart from each other, and the liquid developer flows between these two members. By generating an electric field between the two members, the toner and the carrier liquid are separated, and the carrier liquid is then recovered.

JP 2003-270957 A

  The recycling apparatus disclosed in Patent Document 1 uses an electric field to separate the toner and the carrier liquid. If an electric field with sufficient strength for the separation is to be obtained, the interval between the two members is reduced. There is a need.

  Although the recycling apparatus of Patent Document 1 is applied to an image forming apparatus, the concentration of toner in the liquid developer brought from the image forming apparatus to the recycling apparatus is not constant. For example, when the image forming apparatus is started up or restarted after a paper jam, there is a possibility that a liquid developer containing high-concentration toner may be supplied to the recycling apparatus.

  When a high-concentration toner is supplied, a relatively thick toner layer is formed between the two members, which causes a problem in collecting the carrier layer.

  The present invention has been made to solve the above problems, and an extraction apparatus capable of suitably extracting a dispersion medium from a dispersoid having a non-constant concentration and the extraction apparatus are formed. An object is to provide an image forming apparatus.

  An extraction apparatus according to one aspect of the present invention includes a liquid tank that contains a liquid sample containing a dispersion medium and a dispersoid, a transport unit that transports the liquid sample from the liquid tank, and the liquid sample from the transport unit. A separation unit including a first surface that receives and conveys, an extraction unit that receives the liquid sample from the separation unit, a first recovery unit that recovers the liquid sample from the extraction unit, the first recovery unit, and the liquid A first conduit extending between the tank, a second conduit extending outward from the first recovery section, a first flow of the liquid sample flowing in the first conduit, and the second conduit A switching unit formed to be able to switch between the second flow of the liquid sample flowing in and a control unit for controlling a switching operation of the switching unit, and a voltage is applied to the liquid sample on the first surface. The first charging means for charging the dispersoid and the first surface, The voltage charging unit applies, characterized in that it comprises a second charging means for charging the opposite polarity (claim 1).

  According to the above configuration, the liquid sample including the dispersion medium and the variable concentration dispersoid is accommodated in the liquid tank. The transport unit transports the liquid sample from the liquid tank to the separation unit. A voltage is applied from the charger to the liquid sample existing on the first surface of the separation unit, and the dispersoid is charged. The first surface of the separation part is charged with the opposite polarity to the charge of the dispersoid. For this reason, the dispersoid is electrically attached to the first surface of the separation portion. As a result, the liquid sample delivered from the separation unit to the extraction unit is mainly composed of the dispersion medium. The liquid sample mainly composed of the dispersion medium is recovered by the first recovery unit. The control unit can use the switching unit to select whether the liquid sample is caused to flow in the first pipe line or whether the liquid sample is caused to flow in the second pipe line. When the liquid sample is caused to flow through the first conduit, the liquid sample is returned to the liquid tank again from the first recovery unit. By repeating such a process, the dispersoid is removed from the liquid sample, and the purity of the dispersion medium can be increased. Therefore, the above configuration can provide an extraction device capable of suitably extracting the dispersion medium from the dispersoid whose concentration is not constant.

  In the above-described configuration, the liquid tank includes a first sensor that detects a concentration of the dispersoid and outputs a signal corresponding to the detected concentration of the dispersoid, and the control unit includes the first sensor in the liquid tank. A storage unit that stores a first threshold value for the concentration of the dispersoid, the first threshold value and the signal of the first sensor are compared, and the concentration of the dispersoid in the liquid tank is greater than the first threshold value. A determination unit that determines whether the concentration is larger, and when the determination unit determines that the concentration of the dispersoid in the liquid tank is greater than the first threshold, the control unit controls the switching unit. The liquid sample is preferably in the first flow (claim 2).

  According to the said structure, when the density | concentration of the dispersoid of the liquid sample in a liquid tank is higher than a 1st threshold value, a liquid sample can be made into a 1st flow and the purity of a dispersion medium can be raised. Therefore, for a liquid sample containing an undesirably high concentration level of dispersoid, the purity of the dispersion medium is returned from the first recovery section to the liquid tank until the concentration of the dispersoid in the liquid sample is lower than the first threshold. Can be raised. Therefore, the above configuration can provide an extraction device capable of suitably extracting the dispersion medium from the dispersoid whose concentration is not constant.

  In the above configuration, the first recovery unit includes a second sensor that detects the concentration of the dispersoid and outputs a signal corresponding to the detected concentration of the dispersoid, and the control unit includes the first recovery unit. A storage unit that stores a second threshold value for the concentration of the dispersoid in the unit, the second threshold value and the signal of the second sensor are compared, and the concentration of the dispersoid in the first recovery unit is A determination unit that determines whether the concentration is greater than a second threshold, and when the determination unit determines that the concentration of the dispersoid in the first recovery unit is greater than the second threshold, the control unit includes: It is preferable that the switching unit is controlled so that the liquid sample is in the first flow.

  According to the above configuration, when the concentration of the dispersoid in the liquid sample in the first recovery unit is higher than the second threshold, the liquid sample can be used as the first flow, and the purity of the dispersion medium can be increased. Therefore, for a liquid sample containing an undesirably high concentration level of dispersoid, the purity of the dispersive medium is returned until the concentration of the dispersoid in the liquid sample is lower than the second threshold value from the first recovery unit to the liquid tank. Can be raised. Therefore, the above configuration can provide an extraction device capable of suitably extracting the dispersion medium from the dispersoid whose concentration is not constant.

  In the above configuration, the control unit includes a timer, and after the timer measures a predetermined time from when the extraction device is activated, the switching unit switches from the first flow to the second flow. Preferably, the control unit controls the switching unit so as to switch the flow of the liquid sample.

  According to the above configuration, the liquid sample returns from the first recovery unit to the liquid tank for a predetermined time after the extraction device is activated, and the purity of the dispersion medium is improved. Therefore, it is possible to reliably extract a high-purity dispersion medium even at the start-up time of the apparatus.

  The said structure WHEREIN: It is preferable to further provide the 2nd collection | recovery part which collect | recovers the said liquid sample which remains on the said 1st surface after finishing the delivery of the said liquid sample to the said extraction part (Claim 5).

  According to the said structure, a dispersoid can be collect | recovered. As described above, by repeatedly returning the liquid sample from the first recovery section to the liquid tank, the dispersoid is repeatedly separated from the liquid sample, so that the recovery rate of the dispersoid can be increased.

  In the above configuration, it is preferable that the extraction unit is maintained at a ground potential.

  According to the above configuration, the dispersoid does not unnecessarily move toward the extraction unit, and the extraction efficiency of the dispersion medium can be increased.

  The said structure WHEREIN: The said conveyance part is a conveyance roller containing the surrounding surface which contacts the said liquid sample in the said liquid tank and carry | supports this liquid sample, The said separation part is used as the said 1st surface, and the said Preferably, the separation roller includes a peripheral surface that contacts the peripheral surface of the transport roller, and the extraction unit is an extraction roller that contacts the peripheral surface of the separation roller and receives the liquid sample. ).

  According to the above configuration, it is possible to suitably extract the dispersion medium from the liquid sample while transporting the liquid sample via the three connected rollers.

  An image forming apparatus according to another aspect of the present invention includes a sheet conveying unit that conveys a sheet, and a toner image formed using a liquid developer containing toner and a carrier liquid, and is conveyed by the conveying unit. An image carrier that forms the toner image on a sheet; and a recovery mechanism that recovers the liquid developer that has not been consumed for forming the toner image on the sheet. A liquid tank that contains the liquid developer, a transport unit that transports the liquid developer from the liquid tank, a separation unit that includes a first surface that receives and transports the liquid developer from the transport unit; An extraction unit that receives the liquid developer from the separation unit; a first recovery unit that recovers the liquid developer from the extraction unit; and a first conduit that extends between the first recovery unit and the liquid tank. , Extending from the first recovery part to the outside The second pipe and the first flow of the liquid developer flowing in the first pipe and the second flow of the liquid developer flowing in the second pipe are formed to be switchable. A switching unit; and a control unit that controls a switching operation of the switching unit, wherein the separation unit conveys the liquid developer toward the extraction unit, and the first surface on the first surface. And a charger for charging the toner by applying a voltage to the liquid developer, wherein the first surface is charged with a polarity opposite to the voltage applied by the charger. ).

  According to the above configuration, a toner image is formed on the sheet conveyed by the conveyance unit using the liquid developer. The liquid developer that has not been consumed for forming the toner on the sheet is recovered by the recovery mechanism. The recovery mechanism includes a liquid tank that stores the recovered liquid developer. The transport unit of the recovery mechanism transports the liquid developer from the liquid tank to the separation unit. A voltage is applied from a charger to the liquid developer existing on the first surface of the separation unit, and the toner is charged. The first surface of the separation unit is charged with a polarity opposite to that of the toner. For this reason, the toner is electrically attached to the first surface of the separation portion. As a result, the liquid developer delivered from the separation unit to the extraction unit is mainly composed of the carrier liquid. The liquid developer mainly composed of the carrier liquid is recovered by the first recovery unit. The control unit can use the switching unit to select whether the liquid sample is caused to flow in the first pipe line or whether the liquid sample is caused to flow in the second pipe line. When the liquid sample is caused to flow through the first conduit, the liquid developer is returned from the first recovery unit to the liquid tank again. By repeating such steps, the toner is removed from the liquid developer, and the purity of the carrier liquid can be increased. Therefore, the above configuration can provide an image forming apparatus capable of suitably extracting the carrier liquid with respect to the toner whose density is not constant.

  As described above, the extraction apparatus and the image forming apparatus according to the present invention can appropriately extract a dispersion medium for a dispersoid having a non-constant concentration.

It is a figure which shows schematic structure of the extraction apparatus which concerns on one Embodiment of this invention. It is a figure explaining the process of isolate | separating a liquid sample into a dispersoid and a dispersion medium using the extraction apparatus shown by FIG. It is a block diagram which shows the function structure of the control part of the extraction apparatus shown by FIG. It is a figure which shows schematic structure of the image forming apparatus in which the principle of the extraction apparatus shown by FIG. 1 thru | or FIG. 3 was integrated. It is a schematic block diagram of the image forming apparatus shown by FIG. FIG. 5 is a schematic configuration diagram of an image forming unit provided in the image forming apparatus shown in FIG. 4. FIG. 7 is a schematic configuration diagram of a system for circulating a liquid developer of the image forming apparatus illustrated in FIG. 6.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that terms used in the following description, such as “up”, “down”, “left”, “right” and the like, are merely for the purpose of clarifying the explanation and do not limit the present invention. Not what you want. Further, the term “sheet” used in the following description means copy paper, tracing paper, cardboard, OHP sheet, and other sheets capable of forming an image. Further, the terms “upstream” and “downstream” used in the following description are “upstream” or “downstream” in the flow direction of the liquid sample or “upstream” in the sheet conveyance direction, unless otherwise specified. Means “downstream”. In addition, the terms “leading end” and “proximal end” or similar terms used for the pipes in the following description are pipes located downstream of the flow of the liquid sample flowing in the pipes. It means the end of the channel and the end of the pipe located upstream.

  FIG. 1 is a schematic configuration diagram of an extraction apparatus according to an embodiment of the present invention. 1 is supplied with a liquid developer as a liquid sample. However, the present invention is not limited to this, and an arbitrary liquid sample containing a dispersoid and a dispersion medium can be used. Can be used. The liquid developer used in the present embodiment contains toner as a dispersoid and carrier liquid as a dispersion medium.

  The extraction device 500 includes a housing 510 formed in a substantially rectangular parallelepiped shape, and a control unit 550 that controls an electronic device constituting the extraction device 500. The extraction device 500 further includes a supply pipe line 520 that protrudes from an upstream wall 511 located on the upstream side of the side wall of the housing 510 to the internal space of the housing 510 and a liquid tank 530 disposed inside the housing 510. Prepare. The liquid tank 530 is a box that opens upward. The distal end portion of the supply pipe line 520 communicates with the internal space of the liquid tank 530. A pump 521 is disposed in the middle of the supply pipeline 520. The pump 521 sends a liquid sample that has not been subjected to concentration adjustment to the liquid tank 530 under the control of the control unit 550. Therefore, the liquid tank 530 contains a liquid sample containing a dispersion medium and a variable concentration dispersoid. The liquid tank 530 may be provided with a first sensor 531 for detecting the concentration of the dispersoid. When the dispersoid is, for example, toner, an optical sensor such as a reflective optical sensor and / or a transmissive optical sensor can be suitably used as the first sensor 531. The first sensor 531 outputs a signal corresponding to the concentration of the dispersoid of the liquid sample in the liquid tank 530 to the control unit 550.

  The extraction apparatus 500 further includes a separation unit 540 that separates the liquid sample into a dispersoid and a dispersion medium, and a conveyance roller 560 that is used as a conveyance unit that carries and conveys the liquid sample from the liquid tank 530 to the separation unit 540. The transport roller 560 is a cylindrical rotating body. The lower part of the transport roller 560 is immersed in the liquid sample in the liquid tank 530, and the upper part of the transport roller 560 protrudes above the liquid tank 530. Separation unit 540 includes a cylindrical separation roller 541 having a peripheral surface (first surface) that contacts the peripheral surface of transport roller 560. The conveyance roller 560 and the separation roller 541 are connected to a motor (not shown) that is driven under the control of the control unit 550. For example, the transport roller 560 rotates clockwise at a peripheral speed of 1330 mm / s, and the separation roller rotates counterclockwise at a peripheral speed of 1200 mm / s.

  When the transport roller 560 rotates, the peripheral surface immersed in the liquid sample in the liquid tank moves upward. A liquid sample adheres to the peripheral surface due to surface tension. Thereafter, when the peripheral surface of the transport roller 560 to which the liquid sample is attached contacts the peripheral surface of the separation roller 541, a part of the liquid sample is transferred to the separation roller 541 by the surface tension of the liquid sample, and the separation roller 541 receives the liquid sample. It is received from the conveyance roller 560. As a result, the peripheral surface of the separation roller 541 is at least partially covered with a thin film of a liquid sample.

  FIG. 2 is a diagram illustrating a process of separating a thinned liquid sample into a dispersoid and a dispersion medium. A process of separating a liquid sample into a dispersoid and a dispersion medium will be described with reference to FIG. 1 together with FIG.

  As shown in FIG. 2, the separation unit 540 further includes a charger 542 disposed in the vicinity of the peripheral surface of the separation roller 541, and a power source 543 that supplies electric energy to the charger and the separation roller 541. . The power source 543 is electrically connected to the control unit 550 and operates under the control of the control unit 550. The charger 542 is supplied with electric energy from the power source 543 and applies, for example, a voltage of +4 KV to the liquid sample L existing on the peripheral surface of the separation roller 541. As a result, the toner particles T used as the dispersoid are charged with a positive polarity. On the other hand, the power source 543 has a reverse polarity with respect to the toner particles T that charge the peripheral surface of the separation roller 541 in the range of +10 V to +60 V by applying a voltage of −400 V to the rotating shaft of the separation roller 541, for example. To charge. As a result, in the liquid sample L existing on the circumferential surface of the separation roller 541 before passing through the charger 542, the toner particles T are irregularly suspended, whereas the separation after passing through the charger 542 is performed. In the liquid sample L existing on the peripheral surface of the roller 541, the toner particles T are electrically strongly attached to the peripheral surface of the separation roller 541.

  Please refer to FIG. 1 again. The extraction apparatus 500 further includes an extraction unit that receives the liquid sample after the separation process described with reference to FIG. 2 from the separation unit 540. In the present embodiment, a cylindrical extraction roller 570 is used as the extraction unit. The peripheral surface of the extraction roller 570 is in contact with the peripheral surface of the separation roller 541. A ground wire (not shown) extends from the extraction roller 570 and is grounded. Therefore, the extraction roller 570 maintains the ground potential. The extraction roller 570 is connected to a motor (not shown) that operates under the control of the control unit 550, and rotates clockwise at a peripheral speed equal to that of the separation roller 540, for example.

  The peripheral surface of the separation roller 541 conveys the liquid sample subjected to the separation process described with reference to FIG. 2 toward the extraction roller 570. As described above, since the extraction roller 570 is maintained at the ground potential, the dispersoid does not move unnecessarily toward the extraction roller 570 at the contact position between the peripheral surface of the separation roller 541 and the peripheral surface of the extraction roller 570. Most of the dispersoid is maintained in the state of being electrically attached to the peripheral surface of the separation roller 541 and is conveyed downstream. Therefore, the liquid sample mainly composed of the dispersion medium is transferred to the extraction roller 570 by the surface tension.

  The extraction device 500 further includes a first recovery unit 580 that recovers the liquid sample from the extraction roller 570 and a second recovery unit 590 that recovers the liquid sample from the separation roller 541. The first recovery unit 580 includes a first recovery container 581 for storing a liquid sample, and a first blade 582 that contacts the extraction roller 570 and guides the liquid sample to the first recovery container 581. As described above, the liquid sample transferred to the extraction roller 570 has a dispersion medium as a main component. Therefore, the liquid sample stored in the first recovery container 581 has a dispersion medium as a main component.

  The first recovery unit 580 further includes a second sensor 583 that detects the concentration of the dispersoid in the liquid sample in the first recovery container 581 and outputs a signal corresponding to the detected concentration of the dispersoid to the control unit 550. Including.

  The second recovery unit 590 includes a second recovery container 591 for storing the liquid sample, and a second blade 592 that contacts the separation roller 541 and guides the liquid sample to the second recovery container 591. As described above, the liquid sample mainly composed of the dispersoid remains on the peripheral surface of the separation roller 541 after the liquid sample is transferred to and from the extraction roller 570. The liquid sample containing the dispersoid as a main component is scraped off by the second blade 592 and flows, for example, in the form of a slurry toward the second recovery container 591. The second recovery unit 591 further includes a discharge pipe 593 having a base end connected to the second recovery container 591 and a pump 594 discharged to the middle part of the discharge pipe 593. The pump 594 conveys the liquid sample stored in the second recovery container 591 to the outside of the extraction device 500 under the control of the control unit 550.

  The extraction device 500 further includes a main pipe 551 having a base end connected to the first recovery container 580, a switching valve 552 connected to the tip of the main pipe 551, a base end connected to the switching valve 552, and a liquid. A circulation line 553 including a tip connected to the tank 530 and a discharge line 554 connected to the switching valve 552 and guiding the liquid sample to the outside of the extraction device 500 are included. Under the control of the control unit 550, the switching valve 552 serves as a switching unit that opens one of the route to the circulation conduit 553 and the route to the discharge conduit 554 and closes the other. When the switching unit 552 opens a path to the circulation line 553, the main line 551 and the circulation line 553 constitute a first line for further removing dispersoids from the liquid sample. When the switching unit 552 opens a path to the discharge pipe 554, the main pipe 551 and the discharge pipe 554 constitute a second pipe extending outside so as to guide the liquid sample to the outside of the extraction device 500. In FIG. 1, a pump 555 is disposed in the middle of the circulation line 553, but a sufficient height difference is provided between the first recovery container 581 and the liquid tank 530, and the first recovery container 581 Pump 555 is not required if a first flow of liquid sample towards liquid tank 530 can be created. A pump 556 is disposed in the middle of the discharge pipe 554, and the pump 556 creates a second flow of the liquid sample toward the outside of the extraction device 500.

  FIG. 3 is a block diagram illustrating a functional configuration of the control unit 550. The control unit 550 will be described with reference to FIG.

  The control unit 550 includes a timer 557 configured from a clock and the like, a storage unit 558 configured from a storage element such as a ROM and a RAM, a program stored in the storage element such as a ROM and a RAM, and a CPU that executes the program. The determination part 559 comprised from these is included. The storage unit 558 stores a first threshold value for the concentration of the dispersoid in the liquid sample in the liquid tank 530 and a second threshold value for the concentration of the dispersoid in the liquid sample in the first recovery container 581.

  The first sensor 531 transmits a signal corresponding to the concentration of the dispersoid detected in the liquid tank 530. When the determination unit 559 compares the signal of the first sensor 531 with the first threshold value and determines that the concentration of the dispersoid in the liquid tank 530 exceeds the first threshold value, the control unit 550 Then, a signal for controlling the switching valve 552 is output to close the path toward the discharge pipe 554 and open the path toward the circulation pipe 553. As a result, the flow of the liquid sample from the first recovery container 581 becomes a first flow (a flow from the first recovery container 581 toward the liquid tank 530). When the determination unit 559 compares the signal of the first sensor 531 with the first threshold value and determines that the concentration of the dispersoid in the liquid tank 530 is lower than the first threshold value, the control unit 550 Outputs a signal for controlling the switching valve 552, opens a path toward the discharge pipe 554, and closes a path toward the circulation pipe 553. As a result, the flow of the liquid sample from the first recovery container 581 becomes a second flow (a flow from the first recovery container 581 toward the outside of the extraction device 500).

  The second sensor 583 transmits a signal corresponding to the concentration of the dispersoid detected in the first collection container 581. When the determination unit 559 compares the signal of the second sensor 583 with the second threshold value and determines that the concentration of the dispersoid in the first recovery container 581 exceeds the second threshold value, the control unit 550 outputs a signal for controlling the switching valve 552, closes the path toward the discharge pipe 554, and opens the path toward the circulation pipe 553. As a result, the flow of the liquid sample from the first recovery container 581 becomes a first flow (a flow from the first recovery container 581 toward the liquid tank 530). When the determination unit 559 compares the signal of the second sensor 583 with the second threshold value and determines that the concentration of the dispersoid in the liquid tank 530 is lower than the second threshold value, the control unit 550 Then, a signal for controlling the switching valve 552 is output to open a path toward the discharge pipe 554 and close a path toward the circulation pipe 553. As a result, the flow of the liquid sample from the first recovery container 581 becomes a second flow (a flow from the first recovery container 581 toward the outside of the extraction device 500).

  When the difference between the output of the first sensor 531 and the output of the second sensor 583 is smaller than a predetermined value, the determination unit 559 does not suitably perform the separation process described in relation to FIG. May be determined. In this case, the control unit 550 may output a signal for notifying the user of the abnormality.

  The timer 557 measures the operation time of the extraction device 500 from when the extraction device 500 is started and the pump 521 starts to rotate. When the extraction device 500 is activated, the control unit 550 transmits a control signal to the switching valve 552, and the switching valve 552 closes the path toward the discharge pipe 554 under the control of the control unit 550 and the circulation pipe. Open a route to 553. As a result, the flow of the liquid sample from the first recovery container 581 becomes a first flow (a flow from the first recovery container 581 toward the liquid tank 530).

  When the determination unit 559 determines that a predetermined time has elapsed since the extraction device 500 is activated by the measurement of the timer 557, the control unit 550 transmits a control signal to the switching valve 552, and the switching valve 552 is connected to the control unit 550. Under control, the path toward the discharge pipe 554 is opened and the path toward the circulation pipe 553 is closed. As a result, the flow of the liquid sample from the first recovery container 581 becomes a second flow (a flow from the first recovery container 581 toward the outside of the extraction device 500). In this way, it is possible to reliably extract the dispersion medium even when the extraction apparatus 500 is activated.

  FIG. 4 is a schematic configuration diagram of an image forming apparatus in which the extraction device 500 described with reference to FIGS. 1 to 3 is incorporated. FIG. 5 is a schematic cross-sectional view of the color printer 1 excluding the portion of the liquid developer circulating device. FIG. 6 is an enlarged cross-sectional view showing one of the image forming units. The image forming apparatus shown in FIGS. 4 to 6 is a color printer. However, the image forming apparatus may be a copier, a facsimile machine, a multifunction machine including these functions, or another apparatus capable of forming an image on a sheet. You can also.

  As shown in FIG. 4, the color printer 1 is arranged in an upper main body 1A in which various units and parts for image formation are stored, and a lower part of the upper main body 1A, and a liquid developer circulation for each color. It comprises a lower main body 1B in which devices LY, LM, LC, and LB (mixed liquid supply system) are stored. Here, the piping connecting the upper main body 1A and the lower main body 1B is not shown.

  As shown in FIG. 5, the upper main body 1 </ b> A is formed by a tandem image forming unit 2 that forms a toner image based on image data, a sheet storage unit 3 that stores sheets, and an image forming unit 2. A secondary transfer unit 4 for transferring the transferred toner image onto the sheet, a fixing unit 5 for fixing the transferred toner image on the sheet, a discharge unit 6 for discharging the fixed sheet, and a sheet storage unit 3. And a sheet conveying unit 7 for conveying the sheet from the discharge unit 6 to the discharge unit 6.

  The image forming unit 2 includes an intermediate transfer belt 21, a cleaning unit 22 for the intermediate transfer belt 21, and an image forming unit corresponding to each of yellow (Y), magenta (M), cyan (C), and black (Bk). FY, FM, FC, and FB.

  The intermediate transfer belt 21 is an endless belt, ie, a belt-like member that has conductivity and is wider than the maximum length sheet in the direction perpendicular to the usable sheet conveying direction. And in FIG. 5, it is cyclically driven clockwise. In the circulation driving of the intermediate transfer belt 21, the surface facing outward is hereinafter referred to as a front surface, and the other surface is referred to as a back surface.

  Four image forming units FY, FM, FC, and FB are arranged near the intermediate transfer belt 21 and arranged between the cleaning unit 22 and the secondary transfer unit 4 of the intermediate transfer belt 21. The order of arrangement of the image forming units FY, FM, FC, and FB is not limited to this, but the arrangement shown in FIGS. 4 and 5 reduces the influence on the completed image due to the color mixture of the respective colors.

  The image forming units FY, FM, FC, and FB include a photosensitive drum 10, a charger 11, an LED exposure device 12, a developing device 14, a primary transfer roller 20, a cleaning device 26, and a charge removal device 13. And a carrier liquid removing roller 30. Further, among the image forming units, the image forming unit FB located closest to the secondary transfer unit 4 is not provided with the carrier liquid removal roller 30, but the other configurations are the same.

  Corresponding to the image forming units FY, FM, FC, and FB, liquid developer circulating devices LY, LM, LC, and LB are provided to supply and collect the liquid developers of the respective colors.

  The circumferential surface of the cylindrical photosensitive drum 10 can carry a toner image including a charged toner (charged to a positive polarity in this embodiment). The photosensitive drum 10 shown in FIGS. 5 and 6 can rotate counterclockwise. The charger 11 uniformly charges the surface of the photosensitive drum 10.

  The exposure device 12 has a light source such as an LED, and irradiates light onto the surface of the uniformly charged photoreceptor drum 10 according to image data input from an external device. As a result, an electrostatic latent image is formed on the surface of the photosensitive drum 10.

  The developing device 14 holds the liquid developer containing the toner and the liquid carrier so as to face the electrostatic latent image on the surface of the photosensitive drum 10, thereby attaching the toner to the electrostatic latent image. As a result, the electrostatic latent image is developed as a toner image.

  As shown in FIG. 6, the developing device 14 includes a developing container 140, a developing roller 141, a supply roller 142, a support roller 143, a supply roller blade 144, a development cleaning blade 145, a developer recovery device 146, and a development roller charger 147. Including.

  The developing container 140 is supplied with a liquid developer including toner particles and a liquid carrier. The liquid developer is supplied into the developing container 140 from the supply nozzle 278 after density adjustment between the toner and the carrier is performed in advance. The liquid developer is supplied toward the nip portion between the supply roller 142 and the support roller 143, and the surplus portion falls below the support roller 143 and is stored at the bottom of the developing container 140. The stored liquid developer is recovered through the pipe 82 using a liquid developer circulating device.

  The support roller 143 is disposed substantially at the center of the developing container 140 and abuts against the supply roller 142 from below to form a nip portion. The supply roller 142 is not directly above the support roller 143 but is disposed obliquely above in a direction away from the supply nozzle 278. A groove for holding the liquid developer is provided on the peripheral surface of the supply roller 142. As indicated by dotted arrows in the figure, the support roller 143 rotates counterclockwise and the supply roller 142 rotates clockwise.

  The liquid developer supplied from the supply nozzle 278 is temporarily retained on the upstream side in the rotation direction of the nip portion, and is moved upward while being held in the groove of the supply roller 142 as both rollers 142 and 143 rotate. Carried. The supply roller blade 144 is in pressure contact with the peripheral surface of the supply roller 142 and regulates the amount of liquid developer held by the supply roller 142 to be a predetermined amount. Excess liquid developer scraped off by the supply roller blade 144 is received at the bottom of the developing container 140.

  The developing roller 141 is disposed in the upper opening of the developing container 140 so as to be in contact with the supply roller 142. The developing roller 141 is rotated in the same direction as the supply roller 142 (the surface of the developing roller 141 moves in the opposite direction to the surface of the supply roller 142 in the nip portion where the developing roller 141 and the supply roller 142 abut). As a result, the liquid developer held on the peripheral surface of the supply roller 142 is delivered to the peripheral surface of the developing roller 141. Since the layer thickness of the liquid developer on the supply roller 142 is regulated to a predetermined value, the layer thickness of the liquid developer layer formed on the surface of the developing roller 141 is also maintained at a predetermined value.

  The developing roller charger 147 moves the toner in the developer layer carried on the developing roller 141 to the surface side of the developing roller 141 by applying a charging potential having the same polarity as the charging polarity of the toner. As a result, the development efficiency is improved. The developing roller charger 147 faces the circumferential surface of the developing roller 141 on the downstream side in the rotation direction of the contact portion between the developing roller 141 and the supply roller 142 and upstream of the contact portion with the photosensitive drum 10. To be provided.

  The developing roller 141 is in contact with the photosensitive drum 10, and a toner image corresponding to the image data instructed to form is determined by the potential difference between the electrostatic latent image potential on the surface of the photosensitive drum 10 and the developing bias applied to the developing roller 141. Is formed on the surface of the photosensitive drum 10.

  The developing cleaning blade 145 is disposed so as to contact the downstream side in the rotation direction of the contact portion of the developing roller 141 with the photosensitive drum 10, and the liquid development on the surface of the developing roller 141 that has completed the developing operation on the photosensitive drum 10 is performed. Remove the agent.

  The developer recovery device 146 recovers the liquid developer removed by the development cleaning blade 145 and sends the liquid developer to the pipe 81 of the liquid developer circulation device. The liquid developer flows down along the surface of the development cleaning blade 145. Since the viscosity of the liquid developer is high, the developer recovery device 146 is provided with a feed roller for assisting in feeding the liquid developer.

  The primary transfer roller 20 is disposed on the back surface of the intermediate transfer belt 21 so as to face the photosensitive drum 10. A voltage having a polarity opposite to that of the toner in the toner image (minus in the present embodiment) is applied to the primary transfer roller 20 from a power source (not shown). The primary transfer roller 20 applies a voltage having a polarity opposite to that of the toner to the intermediate transfer belt 21 at a position in contact with the intermediate transfer belt 21. Since the intermediate transfer belt 21 has conductivity, the applied voltage attracts toner to the surface side of the intermediate transfer belt 21 and its periphery. The intermediate transfer belt 21 functions as an image carrier that carries a toner image and conveys it to a sheet.

  The cleaning device 26 is a device for cleaning the liquid developer remaining without being transferred from the photosensitive drum 10 to the intermediate transfer belt 21. The cleaning device 26 includes a residual developer conveying screw 261 and a cleaning blade 262. The residual developer transport screw 261 disposed in the cleaning device 26 is scraped off by the cleaning blade 262 and transports the residual developer stored in the cleaning device 26 to the outside of the cleaning device.

  The plate-like cleaning blade 262 extends in the direction of the rotation axis of the photosensitive drum 10 so as to scrape off the liquid developer remaining on the surface of the photosensitive drum 10. The end of the cleaning blade 262 is in sliding contact with the surface of the photosensitive drum 10 and scrapes off the liquid developer remaining on the photosensitive drum 10 as the photosensitive drum 10 rotates.

  The static eliminator 13 has a light source for static elimination, and removes the liquid developer by the cleaning blade 262 and removes the surface of the photosensitive drum 10 with light from the light source in preparation for the next round of image formation.

  The substantially cylindrical carrier liquid removal roller 30 can rotate in the same direction as the photosensitive drum 10 around a rotational axis parallel to the rotational axis of the photosensitive drum 10. The carrier liquid removing roller 30 is disposed on the side where the secondary transfer unit 4 is disposed with respect to the position where the photosensitive drum 10 and the intermediate transfer belt 21 are in contact with each other, and the carrier liquid is removed from the surface of the intermediate transfer belt 21. Remove.

  Please refer to FIG. 5 again. The sheet storage unit 3 stores a sheet for fixing a toner image. The sheet storage unit 3 is disposed below the upper main body 1A. Further, the sheet storage unit 3 includes a paper feed cassette formed so as to be capable of storing sheets.

  The secondary transfer unit 4 transfers the toner image formed on the intermediate transfer belt 21 to a sheet. The secondary transfer unit 4 includes a support roller 41 that supports the intermediate transfer belt 21 and a secondary transfer roller 42 that is disposed to face the support roller.

  The fixing unit 5 disposed on the upper side of the secondary transfer unit 4 fixes the toner image on the sheet. The fixing unit 5 includes a heating roller 51 and a pressure roller 52 disposed to face the heating roller 51.

  The sheet on which the toner image has been fixed by the fixing unit 5 is discharged to the discharge unit 6 disposed at the upper part of the color printer 1. The sheet conveyance unit 7 includes a plurality of conveyance roller pairs, and conveys the sheet from the sheet storage unit 3 to the secondary transfer unit 4, the fixing unit 5, and the discharge unit 6.

  FIG. 7 shows an outline of the whole of one liquid developer circulating device LY. The other liquid developer circulating devices LM, LC, LB have the same configuration. This liquid developer circulation device LY circulates the residual developer (mixture of toner and carrier liquid) scraped from the surface of the developing roller 141 by the developing cleaning blade 145 after supplying the liquid developer to the photosensitive drum 10. Used for reuse.

  The liquid developer circulating device LY includes a residual developer tank 271, a developer container 272, a solid content detection device 273, a carrier tank 274, a toner tank 275, a liquid level detection device 276, a developer reserve tank 277, a liquid developer. The apparatus includes a supply device 278, a liquid developer separation device 28 to which the principle of the extraction device 500 described with reference to FIGS. 1 to 3 is applied, a plurality of pumps P1 to P10, and a control unit 500.

  The residual developer tank 271 is connected to the developing device 14 via the first pipe 81 and the second pipe 82 and accommodates the liquid developer collected from the developing device 14 side. A first pump P1 and a fifth pump P5 are attached in the middle of the first pipe 81 and the second pipe 82, respectively.

  The liquid developer scraped from the surface of the developing roller 141 by the developing cleaning blade 145 after supplying the toner to the photosensitive drum 10 is sent to the residual developer tank 271 through the first pipe 81 by driving the first pump P1. It is done. Further, the liquid developer stored in the developing container 140 without being supplied from the supply roller 142 to the developing roller 141 in the developing container 140 is driven to the residual developer tank 271 through the second pipe 82 by driving the fifth pump P5. Sent.

  The developer container 272 is connected to the residual developer tank 271. The developer container 272 adjusts the toner concentration to an appropriate range by adding a developer or carrier liquid having a toner concentration higher than that of the developer used in the developing device 14 to the residual developer, and the residual developer toner. Adjust the concentration to an appropriate range. The liquid developer whose toner concentration is adjusted is supplied to the developing device 14. The developer container 272 is connected to the residual developer tank 271 via a third pipe 83, and a second pump P2 is attached to the third pipe 83. The liquid developer in the residual developer tank 271 is sent to the developer container 272 through the third pipe 83 by driving the second pump P2.

  The solid content concentration detection device 273 detects the toner concentration of the liquid developer in the developer container 272. A solid concentration detector 273 is connected to the annular fourth pipe 84 connected to the developer container 272. A fourth pump P4 is attached to the annular fourth pipe 84. The liquid developer in the developer container 272 is guided from the inlet end of the fourth pipe 84 to the solid concentration detector 273 by driving the fourth pump P4, and then the developer is accommodated from the outlet end of the fourth pipe 84. Returned to container 272.

  The carrier tank 274 stores a carrier liquid. When the solid concentration detector 273 determines that the toner concentration in the developer container 272 is higher than the appropriate range, the carrier liquid is supplied from the carrier tank 274 into the developer container 272, and the container 272 The toner concentration of the liquid developer inside is lowered. The carrier tank 274 and the developer container 272 are connected by a fifth pipe 85, and the supply of the carrier liquid is executed by driving a third pump P3 provided in the middle of the fifth pipe 85.

  The toner tank 275 stores a liquid developer having a toner concentration higher than that of the developer used in the developing device 14. When the solid content concentration detection device 273 determines that the toner concentration in the developer storage container 272 is lower than the appropriate range, a liquid developer having a high toner concentration is transferred from the toner tank 275 into the developer storage container 272. The toner concentration of the liquid developer in the container 272 is increased. The toner tank 275 and the developer container 272 are connected by a sixth pipe 86. The liquid developer is supplied by driving an eighth pump P8 provided in the middle of the sixth pipe 86.

  The stirring device 276 is a member for stirring the liquid developer in the developer container 272. The purpose of this stirring is to allow the toner or carrier liquid introduced into the developer container 272 for density adjustment to be uniformly mixed with the existing liquid developer in the developer container 272. This is to redisperse the toner that may aggregate in the liquid developer contained in the developer containing container 272. The stirring device 276 includes a rotating shaft and a stirring blade attached to the tip of the rotating shaft. A liquid level detecting member 276a is coaxially assembled to the rotating shaft. The liquid level detection member 276a is driven by a motor (not shown), and the amount of liquid developer is detected based on a change in the load of the motor caused by the liquid level detection member 276a coming into contact with the liquid level of the liquid developer. The

  The developer reserve tank 277 stores a liquid developer to be replenished to the developing device 14. The developer reserve tank 277 is connected to the developer container 272 by a seventh pipe 871, and the liquid developer is supplied from the developer container 272 by driving a sixth pump P6 provided in the middle of the seventh pipe 871. Receive.

  The supply nozzle 278 supplies the liquid developer stored in the developer reserve tank 277 to the developing device 14 (developing container 140). The supply nozzle 278 and the developer reserve tank 277 are connected by an eighth pipe 872, and the supply of the liquid developer is executed by driving a seventh pump P7 attached to the eighth pipe 872.

  Liquid level detection devices (not shown) for detecting the liquid level in these tanks are provided at appropriate positions of the residual developer tank 271, the carrier tank 274, the toner tank 275, and the developer reserve tank 277.

  The liquid developer separation device 28 uses the principle of the extraction device 500 described with reference to FIGS. 1 to 3 to remove the residual developer collected by the cleaning device 26 (for forming a toner image on the sheet). It functions as a recovery mechanism that separates the toner and carrier liquid from the liquid developer that has not been consumed, and extracts and recovers the toner and carrier liquid separately. The cleaning device 26 and the liquid developer separating device 28 are connected by a ninth pipe 881 to which a ninth pump P9 is attached. The residual developer in the cleaning device 26 is sent to the liquid developer separating device 28 by driving the ninth pump P9. The ninth pump 9 and the ninth pipe 881 correspond to the pump 521 and the supply line 520 of the extraction device 500 described with reference to FIGS. 1 to 3. The liquid developer separation device 28 is similar to the extraction device 500 described with reference to FIGS. 1 to 3, and includes a liquid tank 530, a conveyance roller 560, a separation roller 540, an extraction roller 570, a first recovery unit 580, 2 recovery unit 590, switching valve 552, and circulation line 553. The liquid developer separating device 28 separates the developer into toner and carrier liquid through the steps described with reference to FIGS. 1 to 3. A tenth pipe 882 to which a tenth pump P10 is attached is provided between the liquid developer separating device 28 and the carrier tank 274. The carrier liquid extracted by the liquid developer separating device 28 is sent to the carrier tank 274 by driving the tenth pump P10. The tenth pipe 882 corresponds to the discharge conduit 554 described with reference to FIGS. The tenth pump P10 corresponds to the pump 556 described with reference to FIGS.

  The liquid developer circulation device LY shown in FIG. 10 includes a direct connection conduit 910 extending from the carrier tank 274 to the developer reserve tank 277 and a direct connection conduit 920 extending from the toner tank 275 to the developer reserve tank 277. These direct connection pipes 910 and 920 are used to supply a predetermined amount of carrier and toner to the developer reserve tank 277 before circulation. An eleventh pump P11 and a twelfth pump P12 are arranged in the first and second direct connection pipes 910 and 920, respectively, so that carrier and toner can be directly supplied from each tank to the developer reserve tank 277. The carrier and toner supply systems from these first and second direct connection pipes 910 and 920 are used to quickly develop liquid according to a known blending ratio at the start of use of the color printer 1 in which no recovered liquid developer has yet been generated. It is utilized when producing agents.

  The present invention is suitable for various image forming apparatuses such as a color printer, a printer, a copying machine, a facsimile machine, a multi-function machine having these functions, and other apparatuses that need to separate a dispersoid and a dispersion medium. Applicable.

DESCRIPTION OF SYMBOLS 1 ... Color printer 7 ... Sheet conveyance part 10 ... Photosensitive drum 21 ... Intermediate transfer belt 500 ... Extraction device 530 ... Liquid tank 531 ... No. 1 sensor 540... Separation unit 541... Separation roller 542 .. charger (first charging means)
543 ... Power source (second charging means)
550 ... Control unit 551 ... Main pipe 552 ... Switching valve 553 ... Circulation line 554 ... Discharge pipe 557 ... Timer 558 ... Storage unit 559 ... Determination unit 560 ..Conveying roller 570 ... Extraction roller 580 ... First recovery unit 583 ... Second sensor

Claims (8)

A liquid tank containing a liquid sample containing a dispersion medium and a dispersoid;
A transport unit for transporting the liquid sample from the liquid tank;
A separation unit including a first surface for receiving and transporting the liquid sample from the transport unit;
An extraction unit for receiving the liquid sample from the separation unit;
A first recovery unit for recovering the liquid sample from the extraction unit;
A first conduit extending between the first recovery part and the liquid tank;
A second conduit extending outward from the first recovery part;
A switching unit formed to be able to switch between a first flow of the liquid sample flowing in the first conduit and a second flow of the liquid sample flowing in the second conduit;
A control unit for controlling the switching operation of the switching unit,
A first charging means for applying a voltage to the liquid sample on the first surface to charge the dispersoid;
An extraction apparatus comprising: a second charging unit that charges the first surface with a polarity opposite to a voltage applied by the first charging unit. The liquid tank includes a first sensor that detects a concentration of the dispersoid and outputs a signal according to the detected concentration of the dispersoid.
The controller is configured to store a first threshold value for the concentration of the dispersoid in the liquid tank;
Comparing the first threshold and the signal of the first sensor, and determining whether or not the concentration of the dispersoid in the liquid tank is greater than the first threshold,
When the determination unit determines that the concentration of the dispersoid in the liquid tank is greater than the first threshold value, the control unit controls the switching unit to place the liquid sample into the first flow. The extraction device according to claim 1, wherein: The first recovery unit includes a second sensor that detects the concentration of the dispersoid and outputs a signal corresponding to the detected concentration of the dispersoid.
The control unit stores a second threshold value for the concentration of the dispersoid in the first recovery unit;
Comparing the second threshold and the signal of the second sensor, and determining whether or not the concentration of the dispersoid in the first recovery unit is greater than the second threshold,
When the determination unit determines that the concentration of the dispersoid in the first recovery unit is greater than the second threshold value, the control unit controls the switching unit and causes the liquid sample to flow through the first flow. The extraction apparatus according to claim 1, wherein: The control unit includes a timer,
After the timer measures a predetermined time from when the extraction device is activated, the control unit is configured so that the switching unit switches the flow of the liquid sample from the first flow to the second flow. 4. The extraction device according to claim 1, wherein the switching unit is controlled. 5.   5. The apparatus according to claim 1, further comprising a second recovery unit that recovers the liquid sample remaining on the first surface after the delivery of the liquid sample to the extraction unit. The extraction device described.   The extraction device according to claim 1, wherein the extraction unit is maintained at a ground potential. The transport unit is a transport roller that is in contact with the liquid sample in the liquid tank and includes a peripheral surface that carries the liquid sample,
The separation unit is a separation roller that includes a peripheral surface that is used as the first surface and contacts the peripheral surface of the transport roller;
The extraction device according to claim 1, wherein the extraction unit is an extraction roller that abuts on the peripheral surface of the separation roller and receives the liquid sample. A sheet conveying section for conveying the sheet;
An image carrier for carrying a toner image formed using a liquid developer containing toner and a carrier liquid and forming the toner image on a sheet conveyed by the conveyance unit;
A recovery mechanism for recovering the liquid developer that has not been consumed for forming the toner image on the sheet;
The recovery mechanism includes a liquid tank for storing the recovered liquid developer;
A transport unit for transporting the liquid developer from the liquid tank;
A separation unit including a first surface that receives and conveys the liquid developer from the conveyance unit;
An extraction unit for receiving the liquid developer from the separation unit;
A first recovery unit for recovering the liquid developer from the extraction unit;
A first conduit extending between the first recovery part and the liquid tank;
A second conduit extending outward from the first recovery part;
A switching portion formed so as to be switchable between a first flow of the liquid developer flowing in the first pipeline and a second flow of the liquid developer flowing in the second pipeline;
A control unit for controlling the switching operation of the switching unit,
The separation unit includes a first surface that conveys the liquid developer toward the extraction unit;
A charger for applying a voltage to the liquid developer on the first surface to charge the toner;
The image forming apparatus according to claim 1, wherein the first surface is charged with a polarity opposite to a voltage applied by the charger.

Images