JP2009183855A - Filter device and image formation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filter device which is capable of controlling the clogging of a filter member and to provide an image formation device. <P>SOLUTION: In the filter device 80 for separating a toner condensate in the liquid developer, it is provided with a vessel 81, a filter member 82, supply port 83 and a first outlet 84. The filter member 82 is arranged so that the inside of the vessel 81 may be divided into the upper storing part 94 at the upper part and the lower storing part 93 at the lower part and separates the toner condensate from the liquid developer agent. The supply port 83 is a part to supply the liquid developer prior to the filtration to the lower storing part 93. The first outlet 84 is a part to discharge the liquid developer prior to the filtration from the upper storing part 94. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a filtration device and an image forming apparatus.

  In general, a filtration device for separating a solid in a liquid includes a container that contains the liquid and a filter member that separates the solid from the liquid. Here, when the filter member is easily clogged, it is necessary to frequently perform maintenance for exchanging the filter member or cleaning the filter member, which is complicated. For this reason, conventionally, a technique for suppressing clogging in the filter member has been devised.

For example, in the filtration device shown in Patent Document 1, a pressing member is provided. The pressing member is rotatably provided in contact with the filter member. In this filtration device, the solid matter attached to the filter member can be pulverized by the pressing member. Thereby, solid matter becomes difficult to clog a filter member, and clogging of a filter member can be prevented.
JP 2000-338785 A

  However, in the above filtering device, there is a possibility that the clogging of the filter member may be promoted conversely when the pressing member contacts the solid matter or the filter member. For example, when the pressing member is rotated at a high speed in order to promote filtration, solid matter may be melted by frictional heat between the pressing member and the filter member, and the filter member may be easily clogged.

  The subject of this invention is providing the filtration apparatus and image forming apparatus which can suppress clogging of a filter member.

  A filtration device according to a first invention is a filtration device for separating solids in a liquid, and includes a container, a filter member, a supply port, and a first discharge port. The filter member is disposed so as to partition the inside of the container into an upper upper accommodating portion and a lower lower accommodating portion, and separates solids from the liquid. A supply port is a part for supplying the liquid before filtration to a lower accommodating part. A 1st discharge port is a part for discharging | emitting the liquid after filtration from an upper accommodating part.

  In this filtration device, the liquid is supplied to the lower container of the container through the supply port. When the liquid is supplied until the liquid level in the container is located above the filter member, the liquid or the liquid and a minute solid (hereinafter referred to as “liquid etc.”) pass through the filter member and are stored above. The large solid matter is blocked by the filter member. The liquid or the like stored in the upper storage portion is discharged from the first discharge port to the outside of the container. Further, the solid matter blocked by the filter member is deposited at the bottom of the lower accommodating portion.

  Thus, in this filtration device, solid matter can be separated from the liquid. Moreover, since the solid matter can be separated from the filter member without bringing the member into contact with the solid matter, clogging of the filter member can be suppressed.

  The filtration device according to a second aspect of the present invention is the filtration device of the first aspect of the present invention, further comprising a second discharge port that communicates with the lower storage portion and discharges the solid matter accumulated in the lower storage portion.

  In this filtration device, the solid matter accumulated in the lower housing part can be discharged from the second discharge port to the outside of the container. For this reason, a filtration apparatus can be used for a long period of time.

  A filtration device according to a third invention is the filtration device of the first invention or the second invention, wherein the filter member has conductivity, and a conductive portion having conductivity is provided at the bottom of the lower housing portion. ing. The filtration device further includes a voltage applying unit. The voltage applying part generates a potential difference between the filter member and the conductive part so that the solid matter in the liquid is attracted to the conductive part.

  In this filtration device, the solid matter blocked by the filter member is drawn to the conductive portion. For this reason, it becomes easy for a solid substance to separate from a filter member and to precipitate below. Thereby, clogging of the filter member can be further suppressed.

  The filtration device according to a fourth aspect of the present invention is the filtration device of the third aspect, further comprising a cleaning unit that cleans the surface of the conductive unit.

  In this filtration apparatus, the solid substance adhering to the conductive part can be removed from the conductive part by cleaning the surface of the conductive part by the cleaning part. Thereby, it can suppress that the force in which an electroconductive part attracts a solid substance falls.

  A filtration device according to a fifth invention is the filtration device according to any one of the first to fourth inventions, and the filter member is detachably attached to the container.

  In this filtration device, the filter member can be removed from the container and easily replaced.

  An image forming apparatus according to a sixth aspect of the present invention includes an image forming unit and a filtering device. The image forming apparatus forms an image on a medium using a liquid developer containing toner and a carrier liquid. The filtration device separates toner aggregates from the liquid developer. Further, the filtration device includes a container, a filter member, a supply port, and a first discharge port. The filter member is disposed so as to partition the inside of the container into an upper upper accommodating portion and a lower lower accommodating portion, and separates toner aggregates from the liquid developer. The supply port is a part for supplying the liquid developer before filtration to the lower accommodating part. The first discharge port is a portion for discharging the liquid developer after filtration from the upper accommodating portion.

  In this image forming apparatus, the liquid developer is supplied to the lower container of the container through the supply port. When the liquid developer is supplied until the liquid level in the container is positioned above the filter member, the carrier liquid, or the carrier liquid and a small amount of toner (hereinafter referred to as “carrier liquid etc.”) pass through the filter member. Then, the toner agglomerates having a relatively large size are blocked by the filter member. The carrier liquid or the like stored in the upper storage portion is discharged from the first discharge port to the outside of the container. In addition, toner aggregates blocked by the filter member are deposited at the bottom of the lower housing portion.

  As described above, in this image forming apparatus, the toner aggregate can be separated from the liquid developer by the filtration device. Further, since the toner aggregate can be separated from the filter member without bringing the member into contact with the toner aggregate, clogging of the filter member can be suppressed.

  An image forming apparatus according to a seventh aspect is the image forming apparatus according to the sixth aspect, further comprising a liquid developer separating and extracting device. The liquid developer separation and extraction device can separate a toner that is finer than the toner that can be separated by the filtration device, and separates the toner and the carrier liquid from the liquid developer that remains when the image is formed by the image forming unit. Extract the liquid. The filtration device is provided on the upstream side of the liquid developer separation / extraction device in the liquid developer recovery path. Then, the liquid developer discharged from the first discharge port is sent to the liquid developer separation and extraction device.

  In this image forming apparatus, first, a relatively large toner aggregate is separated from the liquid developer in the filtration device. Thereafter, the liquid developer containing the carrier liquid and a minute amount of toner is sent to the liquid developer separation and extraction device, and the carrier liquid is extracted.

  As described above, in this image forming apparatus, the aggregate of toner is removed from the liquid developer before being sent to the liquid developer separation and extraction apparatus. Thereby, the extraction efficiency of the carrier liquid in the liquid developer separation and extraction apparatus can be improved.

  In the filtration apparatus according to the present invention, solids can be separated from the liquid. Moreover, since the solid matter can be separated from the filter member without bringing the member into contact with the solid matter, clogging of the filter member can be suppressed.

  In the image forming apparatus according to the present invention, the toner aggregate can be separated from the liquid developer by the filtration device. Further, since the toner aggregate can be separated from the filter member without bringing the member into contact with the toner aggregate, clogging of the filter member can be suppressed.

1. 1. Configuration 1.1 Overall Configuration FIG. 1 shows an image forming apparatus 1 according to an embodiment of the present invention. The image forming apparatus 1 is a color printer, and includes an image forming unit 2, a paper storage unit 3, a secondary transfer unit 4, a fixing unit 5, a paper transport unit 6, and a discharge unit 7. Yes. The image forming unit 2 is of a tandem type that forms a toner image based on image data. The paper storage unit 3 stores paper that is an example of a recording medium. The secondary transfer unit 4 transfers the toner image formed by the image forming unit 2 onto a sheet. The fixing unit 5 fixes the toner image transferred to the paper on the paper. The paper transport unit 6 transports the paper from the paper storage unit 3 to the discharge unit 7. The discharge unit 7 discharges the paper on which fixing has been completed.

  The image forming unit 2 includes an intermediate transfer belt 21, a cleaning unit 22, and a plurality of image forming units FY, FC, FM, and FB.

  The intermediate transfer belt 21 is an electroconductive, endless, ie, loop-shaped belt member. The intermediate transfer belt 21 is driven to circulate clockwise as indicated by an arrow in FIGS. The intermediate transfer belt 21 is wider than the maximum width of paper that can be used in the image forming apparatus 1. Here, the “width” refers to the length in the direction perpendicular to the paper transport direction. Hereinafter, the surface facing the outside in the circulation drive of the intermediate transfer belt 21 is referred to as a front surface, and the other surface is referred to as a back surface. The intermediate transfer belt 21 is stretched around a driving roller 41, a driven roller 23, and a tension roller 24. When the driving roller 41 is rotated by driving a driving motor (not shown), the intermediate transfer belt 21 is driven. When the intermediate transfer belt 21 is driven, the driven roller 23 and the tension roller 24 are driven to rotate with respect to the intermediate transfer belt 21. The tension roller 24 is a member that applies an appropriate tension to the intermediate transfer belt 21 so that the intermediate transfer belt 21 does not loosen.

  The cleaning unit 22 cleans the intermediate transfer belt 21. The cleaning unit 22 includes a cleaning roller 22a and a cleaning blade 22b.

  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 image forming units FY, FM, FC, and FB correspond to yellow (Y), magenta (M), cyan (C), and black (Bk) colors, respectively. Note that the order of arrangement of the image forming units FY, FM, FC, and FB is not limited to this, but this arrangement is preferable in consideration of the influence of the color mixture on the completed image.

  As shown in FIG. 2, the image forming units FY, FM, FC, and FB include a photosensitive drum 10, a charger 11, an exposure device 12, a developing device 14, a primary transfer roller 20, and a cleaning device 26. And a static elimination device 13 and a carrier liquid removal 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 each image forming unit FY, FM, FC, FB, liquid developer circulating devices LY, LM, LC, LB, toner tanks CB, CY, CC, CM, and main carrier tank MT are provided. The liquid developer of each color is supplied and collected. The liquid developer circulating devices LY, LM, LC, and LB will be described in detail later.

  The photosensitive drum 10 is a cylindrical member, and can carry a toner image including toner charged on its surface (charged positively in this embodiment). The photosensitive drum 10 is a member that can rotate counterclockwise as indicated by a broken-line arrow in FIG.

  The charger 11 is a device that can uniformly charge 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 in accordance with 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. Thereby, the electrostatic latent image is developed as a toner image.

  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.

  The developing container 140 is a container that receives supply of a liquid developer composed of toner and a carrier liquid. As will be described later, the liquid developer is supplied from the supply nozzle 278 into the developing container 140 in a state where the density adjustment between the toner and the carrier has been performed in advance. The liquid developer is supplied toward a portion of the support roller 143 near the nip portion between the supply roller 142 and the support roller 143, and the surplus portion falls below the support roller 143, and the bottom of the developing container 140 Is stored. The stored liquid developer is collected by the liquid developer circulating devices LY, LM, LC, and LB through the flow path R2.

  The support roller 143 is disposed substantially at the center of the developing container 140 and abuts against the supply roller 142 to form a nip portion in a manner of supporting from below. The supply roller 142 is disposed obliquely above the support roller 143, and is displaced from the position directly above the support roller 143 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. 2, 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 the rollers 142 and 143 rotate. Carried to. 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. That is, at the nip portion where the developing roller 141 and the supply roller 142 abut, the surface of the developing roller 141 moves in the opposite direction to the surface of the supply roller 142. 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. Here, 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 the predetermined value.

  The developing roller charger 147 moves the toner in the liquid developer layer carried on the developing roller 141 to the surface side of the developing roller 141 by applying an electric field having the same polarity as the charging polarity of the toner, thereby improving the developing efficiency. It fulfills the action of The developing roller charger 147 faces the circumferential surface of the developing roller 141 on the downstream side in the rotation direction of the developing roller 141 in contact with the supply roller 142 and on the upstream side in contact with the photosensitive drum 10. It is provided as follows.

  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 (development operation).

  The developing cleaning blade 145 is disposed so as to contact the developing roller 141 on the downstream side in the rotation direction of the contact portion of the developing roller 141 with the photosensitive drum 10 and on the upstream side of the contact portion with the supply roller 142. The liquid developer on the surface of the developing roller 141 that has completed the developing operation on the photosensitive drum 10 is removed.

  The developer recovery device 146 recovers the liquid developer removed by the development cleaning blade 145 and sends the liquid developer to the flow path R1 of the liquid developer circulation devices LY, LM, LC, and LB. The liquid developer flows down along the surface of the development cleaning blade 145. However, since the viscosity of the liquid developer is high, the developer recovery device 146 is provided with delivery rollers 34 and 35 for assisting the delivery of the liquid developer. ing.

  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 this embodiment) is applied to the primary transfer roller 20 from a power source (not shown). That is, 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 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, and includes a cleaning blade 262 and a residual developer conveying screw 261. .

  The cleaning blade 262 is a member for scraping off the liquid developer remaining on the surface of the photosensitive drum 10 and is a plate-like member extending in the direction of the rotation axis 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 residual developer conveying screw 261 is disposed in the cleaning device 26. The residual developer transport screw 261 is scraped off by the cleaning blade 262 and transports the liquid developer stored in the cleaning device 26 to the outside of the cleaning device 26.

  The static eliminator 13 has a light source for static elimination, and neutralizes the surface of the photosensitive drum 10 with light from the light source. The neutralization device 13 performs neutralization after the liquid developer is removed by the cleaning blade 262 in preparation for the next image formation.

  The carrier liquid removal roller 30 is a substantially cylindrical member that can rotate around a rotation axis parallel to the rotation axis of the photosensitive drum 10. The carrier liquid removal roller 30 rotates in the same direction as 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. The member to be removed.

  Returning to FIG. 1, the paper storage unit 3 is a part for storing a paper on which a toner image is fixed, and is disposed in the lower part of the image forming apparatus 1. The paper storage unit 3 includes a paper supply cassette 31 that stores paper, a paper supply roller 32, and a paper separation roller pair 33.

  The secondary transfer unit 4 is a part that transfers the toner image formed on the intermediate transfer belt 21 to a sheet, and is disposed opposite to the driving roller 41 that drives the intermediate transfer belt 21 and the driving roller 41. And a secondary transfer roller 42.

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

  The paper transport unit 6 includes a plurality of transport roller pairs 61 and registration roller pairs 62, and transports paper from the paper storage unit 3 to the secondary transfer unit 4, the fixing unit 5, and the discharge unit 6. In FIG. 1, only one pair of transport rollers 61 is shown, but the other transport roller pairs are arranged side by side in a direction perpendicular to the paper surface in FIG.

  The discharge unit 7 is a portion from which the paper on which the toner image has been transferred and fixed by the secondary transfer unit 4 is discharged. The discharge unit 7 includes a plurality of discharge roller pairs 71 and a discharge tray 72 provided on the upper surface of the image forming apparatus 1. Have. In FIG. 1, only the pair of discharge rollers 71 is shown, but the other discharge roller pairs are arranged side by side in a direction perpendicular to the paper surface in FIG.

1.2 Configuration of Liquid Developer Circulation Device LY, LM, LC, LB FIG. 3 shows an outline of the entire liquid developer circulation device LY. The liquid developer circulation device LY is a device for circulating and reusing the liquid developer. Although the structure of the liquid developer circulating device LY will be described here, the other liquid developer circulating devices LM, LC, and LB have the same configuration. Examples of the liquid developer circulated by the liquid developer circulation device LY include a developer (a mixture of toner and carrier liquid) scraped from the surface of the developing roller 141 by the developing cleaning blade 145, and a developing roller from the supply roller 142. There is a developer that has not been supplied to 141, and a developer that has been scraped off from the photosensitive drum 10 by the cleaning device 26.

  The liquid developer circulation device LY includes a residual developer tank 271, a developer storage container 272, a solid concentration detector 273, a carrier tank TY, a toner tank CY, a developer reserve tank 277, and a supply nozzle 278. A residual developer collecting container 279, a filtering device 80, a liquid developer separating and extracting device 28, and a plurality of pumps P1 to P12.

  The residual developer tank 271 is connected to the developing device 14 via a flow path R1. The residual developer tank 271 is a tank that can store the developer scraped from the surface of the developing roller 141 by the developing cleaning blade 145. Further, one pump P1 is attached between the developing device 14 and the residual developer tank 271. The pump P <b> 1 moves the residual developer scraped from the surface of the developing roller 141 to the residual developer tank 271. The residual developer tank 271 is connected to the bottom of the developing device 14 via a flow path R2, and a pump P5 is connected to the flow path R2. The pump P5 sends the liquid developer from the developing container 140 to the residual developer tank 271.

  The developer storage container 272 is connected to the residual developer tank 271 and is a part for preparing the developer to be replenished to the developing device 14 (toner density adjustment). The developer container 272 is connected to the residual developer tank 271 via a flow path R3, and a pump P2 is connected to the flow path R3. The pump P2 sends the liquid developer from the developer tank 271 to the developer container 272.

  The solid content concentration detection device 273 is a device for detecting the toner concentration of the liquid developer in the developer storage container 272, and is connected to an annular flow path R4 connected to the developer storage container 272. ing. A pump P4 is attached to the upstream side of the solid concentration detector 273 in the annular flow path R4. The pump P4 circulates the liquid developer through the flow path R4.

  The carrier tank TY stores a carrier liquid for reducing the toner concentration in the developer storage container 272. The carrier tank TY is connected to the developer container 272 by a flow path R5 to which a pump P3 is attached. The pump P3 sends the carrier liquid from the carrier tank TY to the developer storage container 272. A carrier tank similar to the carrier tank TY is also provided in each of the other liquid developer circulation devices LM, LC, and LB, and the carrier liquid is supplied from the main carrier tank MT common to each color (see FIG. 1). receive. The carrier tank and the main carrier tank MT are connected to each other by a branch pipe for each color (not shown), and a pump (not shown) is provided in each branch pipe. When the carrier liquid in each carrier tank falls below a predetermined amount, a predetermined amount of carrier liquid is sent from the main carrier tank MT to each carrier tank.

  The toner tank CY contains a liquid developer having a high toner concentration for increasing the toner concentration in the developer container 272. The toner concentration of the liquid developer in the toner tank CY is used in the developing device 14. It is higher than the toner concentration of the liquid developer. The toner tank CY is connected to the developer container 272 by a flow path R6 to which a pump P8 is attached. The pump P8 sends the liquid developer described above from the toner tank CY to the developer container 272.

  The developer reserve tank 277 stores a liquid developer to be replenished to the developing device 14 and is connected to the developer storage container 272 via a flow path R7 to which a pump P6 is attached. The pump P6 sends the liquid developer from the developer container 272 to the developer reserve tank 277. The developer reserve tank 277 is connected to the supply nozzle 278 via a flow path R8 to which a pump P7 is attached. The pump P7 sends the liquid developer from the developer reserve tank 277 to the supply nozzle 278.

  The supply nozzle 278 is a device for supplying the liquid developer to the developing device 14.

  The residual developer recovery container 279 is a container for temporarily storing the liquid developer removed from the photosensitive drum 10 by the cleaning device 26.

  The filtering device 80 is a device for separating toner aggregates from the collected liquid developer. The filtration device 80 is connected to the residual developer recovery container 279 by a flow path R9, and is provided on the upstream side of the liquid developer separation and extraction device 28. A pump P9 is provided in the flow path R9, and the liquid developer in the residual developer collection container 279 is sent to the filtration device 80. Further, the flow path R12 is connected to the filtration device 80. The flow path 12 is provided with a pump P12 that discharges toner aggregates separated from the liquid developer in the filtration device 80 to the outside. The detailed structure of the filtration device 80 will be described later.

  The liquid developer separating and extracting device 28 is a device for separating the liquid developer into toner and carrier liquid and extracting the carrier liquid and toner separately. The liquid developer separation / extraction device 28 is disposed on the downstream side of the filtration device 80. The liquid developer separation / extraction device 28 is connected to the filtration device 80 by a flow path R11. A pump P11 is provided in the flow path R11, and the liquid developer is sent from the filtration device 80 to the liquid developer separation and extraction device 28. The liquid developer separating and extracting device 28 separates the liquid developer stored in the residual developer collecting container 279 into toner and carrier liquid, and extracts the carrier liquid. The liquid developer separating and extracting device 28 can separate a toner that is finer than the toner that can be separated by the filtering device 80. The liquid developer separation / extraction device 28 is connected to the carrier tank TY by a flow path R10. A pump P10 is provided in the flow path R10, and the carrier liquid separated in the liquid developer separation and extraction device 28 is sent to the carrier tank TY.

1.3 Configuration of Filtration Device 80 A sectional view showing the configuration of the filtration device 80 is shown in FIG. The filtration device 80 includes a container 81, a filter member 82, a supply port 83, a first discharge port 84, a second discharge port 86, an electrode plate 87, a voltage application unit 88, a cleaning unit 89, Have

  The container 81 has a substantially cylindrical outer shape, and has a space through which the liquid developer passes. The container 81 has a lower container 91 and an upper container 92 formed separately.

  The lower container 91 generally constitutes the lower half of the container 81. A supply port 83 is provided on the side surface of the lower container 91. The supply port 83 is connected to the flow path R <b> 9 described above, and the hole 95 of the supply port 83 communicates with the inside of the lower container 91. Thereby, the liquid developer before filtration is supplied from the supply port 83 to the lower accommodating portion 93. A second discharge port 86 is provided at the bottom of the lower container 91. The hole 96 of the second discharge port 86 communicates with the lower container 91, and the second discharge port 86 is connected to the flow path R12 described above. The toner aggregate accumulated in the lower container 91 is discharged from the second discharge port 86 to the outside of the container 81. A hole 97 is provided at the center of the bottom surface of the lower container 91, and a rotation shaft 98 and a packing 99 of a cleaning unit 89 described later are inserted into the hole 97. Further, as shown in FIGS. 4 and 5, the inner peripheral surface of the upper end portion of the lower container 91 is slightly enlarged in diameter, and a stepped portion 73 is formed. The lower half of the filter member 82 is fitted to the stepped portion 73 (see FIGS. 4 and 6).

  The upper container 92 constitutes approximately the upper half of the container 81. A first discharge port 84 is provided on the side surface of the upper container 92. The hole 74 of the first discharge port 84 communicates with the inside of the upper container 92, and the first discharge port 84 is connected to the flow path R11 described above. Thus, the filtered liquid developer in the upper container 92 is discharged from the first discharge port 84 to the outside of the container 81 and supplied to the liquid developer separation and extraction device 28. Further, the lower end portion of the inner peripheral surface of the upper container 92 has an enlarged diameter, and a stepped portion 75 is formed. The upper half of the filter member 82 is fitted to the stepped portion 75.

  The filter member 82 is disposed so as to partition the inside of the container 81 into an upper upper accommodating portion 94 and a lower lower accommodating portion 93. Here, since the filter member 82 is disposed between the upper container 92 and the lower container 91, the upper container 92 constitutes the upper accommodating portion 94, and the lower container 91 constitutes the lower accommodating portion 93. . As shown in FIG. 7, the filter member 82 has a frame portion 76 and a net portion 77. The frame portion 76 is an annular member and is fitted to the step portions 73 and 75 described above. Thereby, the filter member 82 is attached to the container 81 so that attachment or detachment is possible. The mesh part 77 is attached to the inside of the frame part 76 and separates toner aggregates from the liquid developer. As shown in FIG. 8, the net 77 is formed by alternately weaving wires in the vertical and horizontal directions, and the filtration accuracy is, for example, about 5 μm. In other words, the filter member 82 allows toner aggregates of 5 μm or less to pass through, but blocks those larger than 5 μm. The net portion 77 is made of a conductive metal such as stainless steel. 8B is a cross-sectional view taken along the line AA in FIG. 8A, and FIG. 8C is a cross-sectional view taken along the line BB in FIG. 8A.

  The electrode plate 87 shown in FIG. 4 is provided inside the bottom of the lower housing part 93, and the distance between the electrode plate 87 and the net part 77 is set to 15 mm, for example. The electrode plate 87 covers the entire inner surface (hereinafter simply referred to as “bottom surface”) of the bottom of the lower container 91, and a hole 78 is provided at a position facing the above-described hole 96 of the second discharge port 86. Yes. A hole 79 is provided at a position facing the central hole 97 in the electrode plate 87. The rotation shaft 98 and the packing 99 of the cleaning unit 89 are inserted into the hole 79. The electrode plate 87 is formed of a conductive metal, like the net portion 77.

  The voltage applying unit 88 generates a potential difference between the filter member 82 and the electrode plate 87 so that the toner is attracted to the electrode plate 87. Here, the filter member 82 is grounded, and a negative voltage, for example, a voltage of −3 kV is applied to the electrode plate 87. As described above, since the toner is charged with a positive polarity, toner aggregates are attracted to the electrode plate 87.

  The cleaning unit 89 is a device for cleaning the surface of the electrode plate 87, and has a rotating shaft 98 and blade portions 63 and 64 as shown in FIGS. 4 and 5. The rotary shaft 98 is inserted through the packing 99 into the hole 97 of the lower container 91 and the hole 79 of the electrode plate 87 described above. The upper end portion of the rotating shaft 98 is located in the lower housing portion 93. The blade portions 63 and 64 are attached to the peripheral surface of the upper end portion of the rotation shaft 98. The blade portions 63 and 64 are inclined with respect to the surface of the electrode plate 87, and the lower end portions thereof are in contact with the surface of the electrode plate 87. When the rotating shaft 98 is driven to rotate by a motor (not shown), the blade portions 63 and 64 rotate around the rotating shaft 98. As a result, the blade portions 63 and 64 slide with respect to the surface of the electrode plate 87, and the toner aggregates attached to the surface of the electrode plate 87 can be scraped off.

2. 2. Operation 2.1 Image Forming Operation First, the image forming operation of the image forming apparatus 1 will be described with reference to FIGS. 1 and 2. The image forming apparatus 1 that has received an image forming instruction from a personal computer (not shown) connected to the image forming apparatus 1 outputs toner images of each color corresponding to the image data that has received the generating instruction to the image forming units FY, FM, It is formed using FC and FB. Specifically, an electrostatic latent image based on image data is formed on the photosensitive drum 10, and toner is supplied to the electrostatic latent image from the developing device 14. The toner images formed in the respective image forming units 2 in this way are transferred to the intermediate transfer belt 21 and are superimposed on the intermediate transfer belt 21 to form a color toner image.

  In synchronism with the formation of the color toner image, the paper stored in the paper feed cassette 31 of the paper storage unit 3 is taken out from the paper feed cassette 31 by the paper feed roller 32, and one by one by the separation roller pair 33. It is sent to the transport unit 6. The paper is sent to the registration roller pair 62 by the transport roller pair 61 of the paper transport unit 6, the paper transport posture is corrected, and the paper is temporarily stopped. Then, the toner image is fed from the registration roller pair 62 to the secondary transfer unit 4 at the same timing as the primary transfer to the intermediate transfer belt 21, and the color toner image on the intermediate transfer belt 21 is secondarily transferred to the sheet by the secondary transfer unit 4. Is done. The sheet on which the color toner image is transferred is sent to the fixing unit 5 and the color toner image is fixed on the sheet by the action of heat and pressure.

  The sheet on which the color toner image is fixed is further sent to the discharge unit 7 and discharged by a discharge roller pair 71 to a discharge tray 72 provided outside the image forming apparatus 1.

  The residual liquid developer remaining on the intermediate transfer belt 21 after the secondary transfer is removed by the cleaning roller 22a and the cleaning blade 22b of the cleaning unit 22 of the intermediate transfer belt 21.

2.2 Liquid Developer Circulation Operation Next, an operation of supplying the liquid developer to the developing device 14, that is, a liquid developer circulation operation will be described with reference to FIG.

  The liquid developer remaining on the developing roller 141 without being supplied to the photosensitive drum 10 during the image forming operation is scraped off by the developing cleaning blade 145 and collected in the residual developer tank 271 through the flow path R1. Further, the liquid developer received in the developing container 140 is also sent to the residual developer tank 271 via the flow path R2. When the liquid developer in the developer container 272 is exhausted, the liquid developer is supplied from the residual developer tank 271 to the developer container 272 via the flow path R3. At this time, the liquid developer remaining on the photosensitive drum 10 without being transferred to the intermediate transfer belt 21 is scraped off by the cleaning blade 262 and stored in the residual developer collection container 279.

  The liquid developer recovered in the residual developer recovery container 279 is conveyed to the filtration device 80 via the flow path R9. In the filtering device 80, relatively large toner aggregates are removed from the liquid developer. The liquid developer discharged from the filtration device 80 is conveyed to the liquid developer separation / extraction device 28 via the flow path R11. In the liquid developer separation / extraction device 28, the toner and the carrier liquid are separated and extracted. The carrier liquid extracted by the liquid developer separating and extracting device 28 is sent to the carrier tank TY via the flow path R10.

  On the other hand, the toner concentration of the liquid developer in the developer container 272 is detected by the solid concentration detector 273, and the concentration of the liquid developer in the developer container 272 is adjusted. Here, when the toner concentration is high, the carrier liquid is supplied from the carrier tank TY to the developer container 272 via the flow path R5. When the toner concentration is low, a liquid developer having a toner concentration higher than that of the liquid developer used in the developing device 14 is supplied from the toner tank CY to the developer container 272 via the flow path R6.

  Then, the liquid developer whose density is adjusted is supplied from the developer container 272 to the developer reserve tank 277 as needed through the flow path R7, and the liquid developer stored in the developer reserve tank 277 flows. It is sent to the supply nozzle 278 via the path R8 and is supplied to the developing device 14 from the supply nozzle 278.

2.3 Separation Operation of Toner Aggregate in Filtration Device 80 Next, the separation operation of the toner aggregate in the filtration device 80 will be described based on FIG.

  First, the liquid developer is put into the lower accommodating portion 93 from the supply port 83 by the pump P9 (see FIG. 3).

  The liquid developer containing a minute amount of toner passes through the filter member 82 and enters the upper storage portion 94. Then, the liquid is separated and extracted from the first discharge port 84 by the pump P11 (see FIG. 3).

  On the other hand, toner agglomerates in the liquid developer cannot pass through the filter member 82 and are blocked by the filter 82. The toner agglomerates blocked on the lower surface of the filter member 82 settle and accumulate on the bottom of the lower housing portion 93, that is, on the surface of the electrode plate 87. Here, an electric field is formed between the electrode plate 87 and the filter member 82, and toner aggregates are attracted to the electrode plate 87. The toner agglomerates deposited on the surface of the electrode plate 87 are scraped off from the surface of the electrode plate 87 by the rotation of the cleaning unit 89, and are sucked by the pump P12 (see FIG. 3) and are discharged from the second discharge port 86. It is discharged outside.

  As described above, in the filtering device 80, since the toner can be separated from the filter member 82 without bringing the member into contact with the aggregate, clogging of the filter member 82 can be reduced.

  In addition, by forming an electric field between the filter member 82 and the electrode plate 87, sedimentation of toner aggregates can be promoted, and clogging of the filter member 82 can be further reduced.

  Furthermore, the upper container 92 and the lower container 91 can be separated, and the filter member 82 is detachably attached to the container 81. For this reason, the filter member 82 can be easily replaced during maintenance. It is also possible to clean and reuse the filter member 82.

3. Other embodiments (a)
In the above embodiment, the present invention is applied to the separation of toner aggregates in the liquid developer, but the present invention may be applied to the separation of solids in other liquids. That is, the present invention can be applied to apparatuses other than the image forming apparatus. However, the present invention is particularly effective for a liquid developer having a low glass transition point that can be fixed at a low temperature because the above-described problem of clogging of the filter member is likely to occur.

(B)
In the above embodiment, the filter member 82 has the net part 77 as shown in FIG. 7, but may have a net part having another structure. For example, as shown in FIG. 9, a mesh portion 65 having a weave different from that of the mesh portion 77 may be used. 9B, FIG. 9B is a cross-sectional view taken along the line CC in FIG. 9A, and FIG. 9C is a cross-sectional view taken along the line DD in FIG. 9A.

(C)
In the above-described embodiment, the filtration device 80 is provided on the upstream side of the liquid developer separation / extraction device 28. However, the filtration device 80 is provided at another position of the liquid developer circulation device LY (LM, LC, LB) shown in FIG. It may be provided. For example, it may be provided between the developer reserve tank 277 and the supply nozzle 278.

  (D) In the above embodiment, a color printer is exemplified as the image forming apparatus, but the present invention is not limited to this, and may be applied to a copying machine, a multifunction machine, and the like.

  The present invention has an effect of suppressing clogging of a filter member, and is useful as a filtration device and an image forming device.

1 is a diagram illustrating a configuration of an image forming apparatus. The enlarged view of an image forming unit. The figure which shows the structure of a liquid developer circulation device. Sectional drawing of a filtration apparatus. The perspective view which shows a lower container and a cleaning part. The perspective view which shows the state by which the filter member was attached to the lower container. The perspective view of a filter member. Enlarged view of the net The enlarged view of the net | network part which concerns on other embodiment.

Explanation of symbols

2 Image forming unit 80 Filtration device 81 Container 82 Filter member 83 Supply port 84 First discharge port 86 Second discharge port 87 Electrode plate (conductive portion)
88 Voltage application part 89 Cleaning part

Claims (7)

A filtration device for separating solids in a liquid,
A container,
A filter member that is arranged so as to partition the inside of the container into an upper upper storage portion and a lower lower storage portion, and separates solids from the liquid;
A supply port for supplying the liquid before filtration to the lower housing part;
A first outlet for discharging the filtered liquid from the upper accommodating portion;
A filtration device comprising: Further comprising a second outlet for communicating with the lower accommodating portion and for discharging solid matter accumulated in the lower accommodating portion;
The filtration device according to claim 1. The filter member has conductivity,
A conductive portion having conductivity is provided at the bottom of the lower housing portion,
A voltage applying unit that generates a potential difference between the filter member and the conductive unit so that solids in the liquid are attracted to the conductive unit;
The filtration device according to claim 1 or 2. A cleaning part for cleaning the surface of the conductive part;
The filtration device according to claim 3. The filter member is detachably attached to the container.
The filtration apparatus in any one of Claim 1 to 4. An image forming unit that forms an image on a medium using a liquid developer containing toner and a carrier liquid;
A filtration device for separating toner agglomerates from the liquid developer;
With
The filtration device
A container,
A filter member arranged to divide the interior of the container into an upper upper accommodating portion and a lower lower accommodating portion, and for separating toner aggregates from the liquid developer;
A supply port for supplying a liquid developer before filtration to the lower housing part;
A first discharge port for discharging the filtered liquid developer from the upper housing part;
Having
Image forming apparatus. Liquid developer that can separate toner that is finer than the toner that can be separated by the filtration device, and extracts the carrier liquid by separating the toner and the carrier liquid from the liquid developer that remains when the image is formed by the image forming unit. A further agent separation and extraction device,
The filtration device is provided on the upstream side of the liquid developer separation and extraction device in the liquid developer recovery path, and the liquid developer discharged from the first discharge port is sent to the liquid developer separation and extraction device. Be
The image forming apparatus according to claim 6.

Images