WO2019098030A1

WO2019098030A1 - Image forming apparatus

Info

Publication number: WO2019098030A1
Application number: PCT/JP2018/040615
Authority: WO
Inventors: 幸寛添田
Original assignee: キヤノン株式会社
Priority date: 2017-11-17
Filing date: 2018-10-31
Publication date: 2019-05-23
Also published as: JP2019095489A

Abstract

The present invention is provided with: a photoconductor; a developing device in which an electrostatic latent image formed on the photoconductor is developed into a toner image by means of a liquid developer composed of a toner and a carrier solution; a photoconductor collection unit for collecting the liquid developer that is on the photoconductor; a separation device (34) for separating the liquid developer into a waste liquid including the toner and the carrier solution; a storage container (36) capable of storing the liquid developer collected by the photoconductor collection unit; a first transport path capable of transporting the liquid developer, collected in the photoconductor collection unit, to the storage container (36); and a second transport path capable of transporting the liquid developer, stored in the storage container, to the separation device (34), wherein the storage container (36) has a discharge port (366) for discharging the liquid developer through the second transport path, and the discharge port (366) is positioned higher than the bottom surface of the storage container (36) with respect to the direction of gravity.

Description

Image forming device

The present invention relates to an electrophotographic image forming apparatus that forms an image using a liquid developer.

2. Description of the Related Art Conventionally, an image forming apparatus that forms an image using a liquid developer containing toner and a carrier liquid is known. In an image forming apparatus using a liquid developer, for example, a liquid developer not used in an image forming process is collected from a photosensitive drum, an intermediate transfer roller or the like and reused. Conventionally, a liquid developer collected from a photosensitive drum, an intermediate transfer roller, etc. after transfer of a toner image is transported to a separation device, and the liquid developer is separated by the separation device into waste liquid containing toner and carrier liquid. A process of recycling the liquid is performed (Patent Document 1). In the separation device, the collected liquid developer is supplied to a narrow gap, and an electric field is generated in the gap, whereby toner and carrier liquid in the liquid developer are separated and extracted.

JP, 2008-242436, A

By the way, for example, in the liquid developer collected from the photosensitive drum, there is a possibility that foreign substances and the like attached on the photosensitive drum in the image forming process may be mixed. In the separation device, when foreign matter is mixed in the liquid developer to be separated into waste liquid and carrier liquid, the foreign matter may be retained in the gap causing the above-mentioned electric field to cause failure of the separation device, or to separated carrier liquid There is a possibility that foreign matter may be mixed.

The present invention has been made in view of the above problems, and an object thereof is to provide an image forming apparatus capable of removing foreign matter from a liquid developer supplied to a separation device.

An image forming apparatus according to the present invention includes a photosensitive body, a developing device for developing an electrostatic latent image formed on the photosensitive body into a toner image with a liquid developer composed of toner and carrier liquid, and the photosensitive body on the photosensitive body. A photoreceptor recovery unit for recovering the liquid developer, a separation device for separating the toner and the carrier liquid from the liquid developer, a storage container capable of storing the liquid developer recovered by the photoreceptor recovery unit, A first transport path capable of transporting the liquid developer collected in the body recovery unit to the storage container, and a second transport path capable of transporting the liquid developer stored in the storage container to the separation device The storage container has a discharge port for discharging the liquid developer through the second transport path, and the discharge port is provided above the bottom surface of the storage container in the gravity direction.

According to one aspect of the present invention, foreign matter is removed from the collected liquid developer, and the liquid developer from which foreign matter has been removed is supplied to the separation device to separate the carrier liquid containing no foreign matter from the liquid developer. It can be done with a simple configuration.

Other features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings. In the attached drawings, the same or similar configurations are denoted by the same reference numerals.

FIG. 1 is a schematic configuration view showing an image forming apparatus of the present embodiment. FIG. 2 is a schematic view showing a transport path of the liquid developer in the image forming apparatus of the present embodiment. The external appearance perspective view which shows a isolation | separation extraction apparatus. The perspective view which cuts and shows a part of isolation | separation extraction apparatus. Sectional drawing which shows a part of isolation | separation extraction apparatus. The enlarged view which expands and shows the A section of FIG. The schematic diagram which shows a storage container and a separating device. 5 is a flowchart showing liquid developer supply processing. FIG. 8 is a schematic view showing a transport path of the liquid developer in the image forming apparatus of the other embodiment.

[Image forming apparatus]
The image forming apparatus of the present embodiment will be described. First, the configuration of the image forming apparatus of the present embodiment will be described with reference to FIG. An image forming apparatus 100 illustrated in FIG. 1 is an electrophotographic digital printer that forms a toner image on a recording material S (a sheet, a sheet material such as an OHP sheet, etc.). The image forming apparatus 100 includes a control unit 500 that controls the operation of the image forming apparatus 100. The image forming apparatus 100 is operated based on an image signal under control of the control unit 500, and transfers the toner image formed by the image forming unit 12 to the recording material S sequentially conveyed from the

cassettes

11a and 11b. An image is obtained by fixing. The image signal is sent to the image forming apparatus 100 from an external terminal such as a scanner or a personal computer (not shown).

The image forming unit 12 includes a photosensitive drum 13 as a photosensitive member, a charger 14, a laser exposure device 15, a developing device 16, and a drum cleaner 19. The laser light E is irradiated from the laser exposure device 15 according to the image signal onto the photosensitive drum 13 whose surface is charged by the charger 14, and an electrostatic latent image is formed on the photosensitive drum 13. The electrostatic latent image is developed by the developing device 16 as a toner image. In the case of the present embodiment, the developing device 16 as a developing device contains a liquid developer D in which powder toner as a dispersoid is dispersed in a carrier liquid as a dispersion medium. The developing unit 16 performs development using this liquid developer D.

The liquid developer D is generated by mixing and dispersing the carrier liquid C and the toner T at a predetermined ratio in the mixer 31 as a mixer, and is supplied to the developing device 16. The carrier liquid C for replenishment is accommodated in a carrier tank 32 as a carrier container, and the toner T for replenishment is accommodated in a toner tank 33 as a toner container. Then, according to the mixed state of the carrier liquid C and the toner T in the mixer 31, the carrier liquid C or the toner T is supplied to the mixer 31 from each tank. The mixer 31 contains a stirring blade driven by a motor (not shown), and mixes the supplied carrier liquid and the toner T by stirring to disperse the toner in the carrier liquid.

The liquid developer D supplied from the mixer 31 to the developing device 16 is coated (supplied) on the developing roller 18 by the coating roller 17 in the supply section 16 a of the developing device 16 and used for development. The developing roller 18 carries and conveys a liquid developer on the surface, and develops the electrostatic latent image formed on the photosensitive drum 13 with toner. The carrier liquid C and the toner T remaining on the developing roller 18 after development are collected in the collection section 16 b of the developing device 16. Here, the coating of the liquid developer D from the coating roller 17 to the developing roller 18 and the development from the developing roller 18 to the electrostatic latent image on the photosensitive drum 13 are performed using an electric field.

The toner image formed on the photosensitive drum 13 is primarily transferred to the intermediate transfer roller 20 using an electric field, and conveyed to the nip portion (secondary transfer portion) formed by the intermediate transfer roller 20 and the transfer roller 21. . The liquid developer (toner T and carrier liquid C) remaining on the photosensitive drum 13 (on the photosensitive member) after the primary transfer to the intermediate transfer roller 20 is collected by the drum cleaner 19. The drum cleaner 19 as a photosensitive member recovery unit is made of, for example, a blade-like member made of rubber, and is in contact with the photosensitive drum 13 with a linear pressure of 30 (g / cm). At least one of the intermediate transfer roller 20 and the transfer roller 21 may be an endless belt.

The recording material S accommodated in the

cassettes

11a and 11b is conveyed toward the resist conveyance unit 23 by the

feeding units

22a and 22b configured by conveyance rollers and the like. The resist conveyance unit 23 conveys the recording material S to the nip portion between the intermediate transfer roller 20 and the transfer roller 21 in accordance with the timing of the toner image transferred to the intermediate transfer roller 20.

At the nip portion between the intermediate transfer roller 20 and the transfer roller 21, the toner image is secondarily transferred onto the passing recording material S, and the recording material S onto which the toner image has been transferred is conveyed by the conveyance belt 24 to the fixing device 25. The toner image transferred to the recording material S is fixed. The recording material S on which the toner image is fixed is discharged to the outside of the machine, and the image process is completed. In the present embodiment, the fixing device 25 employs a heat fixing method. In this system, the fixing device 25 has two rollers for sandwiching the recording material S from above and below and pressing them against each other, and the two rollers maintain their surface temperature at about 200.degree. As a result, the surface of the recording material S conveyed at a predetermined process speed (for example, 600 mm / s) is maintained at a temperature of 60 ° C. or higher, which is the glass transition point at which the toner melts. As the toner melts, the toner is fixed on the recording material S. However, when using an ultraviolet curing type liquid developer as the liquid developer D, the fixing device 25 irradiates ultraviolet light (UV light) to cure the liquid developer. The toner is fixed on the recording material S by curing of the carrier liquid.

The intermediate transfer roller 20 as an intermediate transfer member and the transfer roller 21 as a transfer member are respectively provided with an intermediate transfer roller cleaner 26 as an intermediate transfer member recovery portion and a transfer roller cleaner 27 as a transfer member recovery portion. The intermediate transfer roller cleaner 26 recovers the liquid developer (toner T and carrier liquid C) remaining on the intermediate transfer roller 20 after secondary transfer from the intermediate transfer roller 20. The transfer roller cleaner 27 recovers the liquid developer (toner T and carrier liquid C) remaining on the transfer roller 21 after the secondary transfer from the transfer roller 21. In the present embodiment, each of the intermediate transfer roller cleaner 26 and the transfer roller cleaner 27 is formed of a blade-like member made of rubber, and is applied to the intermediate transfer roller 20 and the transfer roller 21 with a linear pressure of 30 (g / cm). Be touched. However, the method of collecting the liquid developer (mainly toner T) remaining on the intermediate transfer roller 20 and the transfer roller 21 is not limited to this. For example, the toner T may be separated by an electric field by bringing a roller-like member into contact with the intermediate transfer roller 20 (on the intermediate transfer member) and the transfer roller 21 (on the transfer member).

[Liquid developer]
As the liquid developer D used in the image forming apparatus 100 of the present embodiment, a liquid developer conventionally used may be used, or an ultraviolet-curable liquid developer may be used. However, in the case where an expensive high-performance carrier liquid is used as the carrier liquid, when the carrier liquid recovered from the photosensitive drum 13 is discarded, the running cost becomes high. Therefore, in order to reduce the running cost, the carrier liquid is efficiently separated and extracted from the recovered liquid developer D and reused.

In the case of an ultraviolet-curable liquid developer, toner particles include a coloring material that emits a color in a toner resin. The toner particles may contain other materials such as a charge control agent, as well as the toner resin and the coloring material. As the toner resin, epoxy resin, styrene acrylic resin, or the like is used. The colorant may be a general organic-inorganic pigment. On the other hand, the curable liquid, which is a carrier liquid, is composed of a charge control agent that causes a charge on the toner surface, a photopolymerization agent that generates an acid upon irradiation with ultraviolet light (UV light), and a monomer that bonds with the acid. . The monomer is a vinyl ether compound that polymerizes by a cationic polymerization reaction. In addition to the photopolymerization agent, a sensitizer may be contained. The photopolymerization agent may reduce the storage stability, so 10 to 5000 ppm of a cationic polymerization inhibitor may be added. In addition, charge control aids, other additives, etc. may be used.

[Conveying of liquid developer]
Next, conveyance of the liquid developer D in the present embodiment will be described with reference to FIG. First, the liquid developer collected by the drum cleaner 19 as described above is sent to the separation and extraction device 34. In the present embodiment, as shown in FIG. 2, the drum cleaner 19 and the separation and extraction device 34 are not directly connected, but are connected via a storage container 36 capable of storing the liquid developer. Specifically, the drum cleaner 19 and the storage container 36 are connected to each other by a drum recovery liquid transport pipe 190 as a first transport path. By connecting the drum cleaner 19 and the storage container 36 by the drum collection liquid transport pipe 190, the liquid developer collected by the drum cleaner 19 can be transported to the storage container 36.

On the other hand, the separation and extraction device 34 and the storage container 36 are connected to each other by a storage liquid transport pipe 360 as a second transport path. The liquid developer stored in the storage container 36 can be transported to the separation and extraction device 34 by the separation and extraction device 34 and the storage container 36 being connected by the storage liquid transport pipe 360. The liquid developer stored in the storage container 36 is conveyed to the separation and extraction device 34 by a pump 49 provided in the middle of the storage liquid transport pipe 360. The storage container 36 described above will be described later (see FIG. 7). The liquid developer remaining on the developing roller 18 after development and collected in the collection section 16 b of the developing device 16 is returned to the mixer 31, but similarly to the liquid developer collected by the drum cleaner 19, the storage container It may be transported to the separation and extraction device 34 via 36.

The separation and extraction device 34 as a separation device to which the liquid developer is transported from the storage container 36 is, as described in detail later, the transported liquid developer as a carrier liquid and a waste liquid W containing toner, paper powder and the like. To separate. The separated waste liquid W is collected in the waste liquid storage container 35.

The transportation of the liquid developer D will be described more specifically. The transport pipes from the carrier tank 32 and the toner tank 33 to the mixer 31 are provided with

solenoid valves

41 and 42, respectively. The

solenoid valves

41 and 42 adjust the supply amounts of the carrier liquid C and the toner T to the mixer 31. From the mixer 31, a liquid developer D necessary for development is supplied to the developing unit 16 using a pump 44.

The liquid developer collected in the collection section 16 b of the developing device 16 is returned to the mixer 31 by the pump 43. This is because the liquid developer collected in the collection section 16b is not used for development or the like and is hardly deteriorated.

As described above, the liquid developer collected by the drum cleaner 19 is transported and stored in the storage container 36 via the drum collected liquid transport pipe 190. Then, as described later, when the liquid developer stored in the storage container 36 exceeds a certain amount, the pump 49 transports the liquid developer to the separation and extraction device 34 via the storage liquid transport pipe 360.

The liquid developer conveyed to the separation and extraction device 34 is separated into the carrier liquid and the waste liquid W. The carrier liquid separated by the separation and extraction device 34 is reusable, and is transported to the carrier tank 32 by the solenoid valve 45 as a carrier supply unit for reuse. On the other hand, since the waste liquid W containing the toner separated by the separation and extraction device 34 is difficult to reuse, it is transported to the waste liquid storage container 35 by the electromagnetic valve 47 provided in the waste liquid transport pipe 340.

Next, separation and extraction of the toner and the carrier liquid in the above-described separation and extraction device 34 will be described with reference to FIGS. 3 to 6. In the present embodiment, the separation and extraction device 34 separates the toner from the liquid developer using an electric field.

The liquid developer is conveyed from the inlet 34 b of the separation and extraction device 34 into the liquid container 346 as shown by the arrows in FIGS. 3 and 4. Then, it is supplied to the buffer container 348 (see FIG. 4) in the liquid storage container 346. In the present embodiment, the buffer container 348 is provided in the separation and extraction device 34, but may be provided alone. The liquid developer supplied to the buffer container 348 is transported by the pump 34c and passes through the filter 34d.

The liquid developer that has passed through the filter 34d is supplied to the supply tray 346a, as shown in FIG. As described in detail later, the liquid developer introduced into the supply tray 346a is separated into the toner and the carrier liquid in the separation and extraction device 34. Then, the extracted toner is sent to the waste liquid storage container 35, and the extracted carrier liquid is transported to the carrier tank 32.

As shown in FIGS. 4 and 5, a coat electrode member 341, an electrode roller 342, a toner collection device 350, and the like are disposed in the liquid storage container 346. The coat electrode member 341 and the electrode roller 342 constitute a pair of first electrodes between which the liquid developer can pass, the electrode roller 342 being one side of the first electrode 342a, and the coat electrode member 341 being the other side. Each has a first electrode 341a. The liquid storage container 346 is a container capable of storing a liquid developer, and includes the above-described supply tray 346a, a discharge unit 346b from which the carrier liquid is discharged, and a collection unit 354 for the waste liquid W.

The electrode roller 342 is, for example, a conductive roller in which a urethane rubber elastic layer is formed by integral molding on a core metal surface layer formed of solid stainless steel and having an outer diameter of 40 mm. The electrode roller 342 receives drive from the outside by a drive motor (see FIG. 7 described later), and rotates in a predetermined direction (arrow direction in FIG. 4 and FIG. 5). In the present embodiment, the rotational speed of the drive motor is 2000 rpm. Then, the electrode roller 342 decelerates the rotation of the drive motor and rotates, for example, at a rotational speed of 400 rpm.

The coat electrode member 341 is disposed via a gap 347 with a part of the surface of the electrode roller 342 as shown in FIGS. 5 and 6. A supply tray 346a is connected to the rotational direction upstream end 347a of the electrode roller 342 in the gap 347 (see FIG. 4). Then, the liquid developer introduced into the supply tray 346a as described above is supplied from the upstream end 347a into the gap 347. Both end portions in the rotational axis direction of the electrode roller 342 in the gap 347 are sealed, and the liquid developer supplied to the gap 347 is transported downstream in the rotational direction in the gap 347 as the electrode roller 342 rotates. . A discharge portion 346b is connected to the downstream end 347b of the gap 347 in the rotational direction of the electrode roller 342 (see FIG. 4). Then, the liquid developer (specifically, the carrier liquid) which has passed through the gap 347 is sent from the discharge portion 346b to the carrier tank 32 via the transport pipe 346c (see FIGS. 2 and 4).

As described above, the coat electrode member 341 disposed via the electrode roller 342 and the gap 347 is formed of a metal such as solid stainless steel to a width of 400 mm, for example. The portion 341x of the coat electrode member 341 has a shape for accommodating a part of the electrode roller 342, and the surface of the portion 341x facing the electrode roller 342 is a predetermined distance (i.e., gap 347) from the surface of the electrode roller 342 It has a curved shape to keep the The predetermined distance is, for example, 0.2 mm.

The coat electrode member 341 and the electrode roller 342 generate an electric field in which the toner in the liquid developer moves to the electrode roller 342 side between the coat electrode member 341 and the electrode roller 342 by a high voltage power source (see FIG. 7 described later) Voltage can be applied. That is, a voltage is applied to the gap 347 such that an electric field is generated such that the toner is attracted to the electrode roller 342.

In this embodiment, since the toner is negatively charged by the charge control agent, for example, minus 300 V is applied to the electrode roller 342 and minus 1000 V is applied to the coat electrode member 341. In this case, while the liquid developer passes through the gap 347, the toner in the liquid developer is moved from the coated electrode member 341 to the electrode roller 342. As a result, since the toner is carried on the electrode roller 342, the toner and the carrier liquid are separated. The separated carrier liquid is discharged to the discharge portion 346b connected to the downstream end 347b of the gap 347.

The toner collection device 350 is located on the downstream side of the coat electrode member 341 with respect to the rotation direction of the electrode roller 342, and collects the toner carried on the electrode roller 342. The toner collection device 350 has a collection roller 351 and a blade member 352.

The recovery roller 351 is, for example, a metal roller formed of solid stainless steel and having an outer diameter of φ20, and is urged toward the electrode roller 342 so as to be in contact with the electrode roller 342. Then, the collection roller 351 abuts on the electrode roller 342, and is driven to rotate in the arrow direction of FIGS. The rotation speed of the collection roller 351 is, for example, 800 rpm. The electrode roller 342 and the recovery roller 351 are disposed substantially in parallel with each other, and both end portions in the rotational axis direction are rotatably supported by the liquid storage container 346. A voltage can be applied to the collection roller 351 and the electrode roller 342 so that an electric field is generated between the collection roller 351 and the electrode roller 342 to move the toner toward the collection roller 351 by a high voltage power supply (see FIG. 7 described later). is there. In the present embodiment, for example, minus 300 V is applied to the electrode roller 342 and minus 200 V is applied to the collection roller 351. Thus, the toner carried on the electrode roller 342 and transported to the collection roller 351 is moved from the electrode roller 342 to the collection roller 351.

The blade member 352 contacts the recovery roller 351 and scrapes the toner on the recovery roller 351. The blade member 352 is disposed on the downstream side of the collecting roller 351 in the rotational direction with respect to the position where the electrode roller 342 and the collecting roller 351 are in contact with each other so as to contact the collecting roller 351 in the counter direction. The blade member 352 is a plate-like member extending along the longitudinal direction (rotational axis direction) of the recovery roller 351, and for example, stainless steel is used. The counter direction is a direction in which the tip of the blade member 352 in contact with the collection roller 351 is in the direction opposite to the rotation direction of the collection roller 351 at the contact position between the blade member 352 and the collection roller 351. is there.

The toner moved from the electrode roller 342 to the collection roller 351 as described above is scraped off by the blade member 352, and is sent to the collection unit 354. The toner collected by the collection unit 354 is sent as the waste liquid W to the waste liquid storage container 35 as described above. The scraping member for scraping the toner from the recovery roller 351 is not limited to the blade member 352, and may be, for example, a brush.

[Reservoir container]
As described above, in the separation and extraction device 34, the toner and the carrier liquid contained in the liquid developer collected by the drum cleaner 19 are separated by electrophoresis. However, the liquid developer collected by the drum cleaner 19 may contain foreign substances (for example, aggregated toner, mold shaving of a mold, paper dust, etc.) during image formation. When foreign matter is contained in the liquid developer, it is difficult to remove foreign matter from the liquid developer in the separation and extraction device 34, and the carrier liquid containing the foreign matter is repeatedly reused to occupy in the liquid developer. The percentage of foreign matter increases. If this happens, foreign matter may stagnate and clog, for example, in a slight gap 347 (see FIG. 5) for generating an electric field, which may cause the failure of the separation and extraction device 34. In addition, when the liquid developer contains a large amount of foreign matter, an image defect is likely to occur. Therefore, it is preferable to remove foreign matter as much as possible from the liquid developer before being sent to the separation and extraction device 34. For that purpose, the storage container 36 is provided in the present embodiment. The storage container 36 will be described with reference to FIG. 7 with reference to FIG.

As shown in FIG. 7, the storage container 36 is formed with an inlet 365 and an outlet 366. The inflow port 365 is connected to a drum collected liquid transport pipe 190 to which the liquid developer collected by the drum cleaner 19 is transported, and the liquid developer can flow in via the drum collected liquid transport pipe 190. On the other hand, the discharge port 366 is connected to a stored liquid transport pipe 360 to which the liquid developer stored in the storage container 36 is transported, and the liquid developer can be discharged through the stored liquid transport pipe 360. Further, an accumulation portion 36a is formed in the storage container 36 so as to be capable of accumulating the foreign matter X contained in the liquid developer. The accumulation portion 36a is formed by providing the discharge port 366 above the bottom surface 36b such that the lowermost surface 366a of the discharge port 366 is at a predetermined height or more from the bottom surface 36b of the storage container 36 in the gravity direction. In other words, the accumulation portion 36 a is a region from the bottom surface 36 b of the storage container 36 to the lowermost surface 366 a of the discharge port 366. As an example, the lowermost surface 366a of the discharge port 366 is provided at a height of 20 mm or more from the bottom surface 36b of the storage container 36, which is a height at which the foreign matter X accumulated in the accumulation portion 36a is hardly discharged. The height of the lowermost surface 366a of the discharge port 366 is not limited to this, and may vary depending on the shape of the storage container 36 and the like.

As described above, in the present embodiment, before the liquid developer collected by the drum cleaner 19 is sent to the separation and extraction device 34, the storage container 36 capable of temporarily storing the liquid developer is provided. An accumulation portion 36a is formed in the storage container 36, and foreign matter contained in the liquid developer is accumulated in the accumulation portion 36a. This is because the specific gravity of the foreign matter contained in the collected liquid developer is larger than the specific gravity of the toner and the carrier liquid, and tends to precipitate on the bottom surface 36 b of the storage container 36. As described above, the foreign matter contained in the liquid developer collected by the drum cleaner 19 is removed, and the liquid developer from which the foreign matter has been removed is supplied to the separation and extraction device 34 to be separated and extracted into the toner and the carrier liquid. The storage container 36 can be provided with a simple configuration.

The storage container 36 may be detachably provided to the apparatus main body 100 a (see FIG. 1) of the image forming apparatus 100. In that case, it is preferable that the user can be notified of the replacement of the storage container 36 when the foreign matter X accumulated in the storage container 36 exceeds a predetermined amount.

By the way, as described above, the separation and extraction device 34 is configured to separate the toner and the carrier liquid contained in the liquid developer collected by the drum cleaner 19 by electrophoresis. Heretofore, the separation and extraction device 34 has always been maintained in operation so that the toner and the carrier liquid can be separated as soon as the liquid developer is transported from the drum cleaner 19. In that case, in the separation and extraction device 34, a state in which a voltage is applied to the coat electrode member 341, the electrode roller 342, and the collection roller 351 (see FIG. 5) continues. Among them, since the electrode roller 342 has a urethane rubber elastic layer on the surface, the deterioration is likely to proceed according to the accumulated voltage application time. Further, the electrode roller 342 and the collection roller 351 are likely to be deteriorated according to the cumulative rotation time.

In order to prevent such deterioration, the operation of the separation and extraction device 34 can be controlled based on the storage amount of the liquid developer stored in the storage container 36 as described below. This point will be described with reference to FIGS. 7 and 8. Although only one high voltage power supply 501 is shown in FIG. 7 for convenience of illustration, it may be plural.

As shown in FIG. 7, the storage container 36 is provided with a liquid level sensor 361 (for example, a float sensor or the like) as a detection unit in order to detect the storage amount of the liquid developer stored. In the liquid level sensor 361, the liquid level of the liquid developer reaches the first liquid level 361A corresponding to the first storage amount, and the liquid level of the liquid developer is higher than the first storage amount. Both the fact that the second liquid level 361B corresponding to the small second storage amount has been reached can be detected. In the case of the present embodiment, the liquid level 361 B is lower than the liquid level 361 A, and is set to the height of the top surface 366 b of the discharge port 366. The liquid level sensor 361 is connected to the control unit 500 so as to allow data communication, and the control unit 500 can acquire the detection result of the liquid level sensor 361.

In addition to the liquid level sensor 361, the control unit 500 is connected to a pump 49 as a conveyance unit, a high voltage power supply 501, and a drive motor 502. As described above, the high voltage power supply 501 applies a voltage to the coat electrode member 341, the electrode roller 342, and the collection roller 351 of the separation and extraction device 34 in order to separate the toner and the carrier liquid from the liquid developer. It is. The drive motor 502 drives the electrode roller 342 of the separation and extraction device 34.

In addition to the use of the liquid level sensor 361 to detect the storage amount of the liquid developer in the storage container 36, a weight sensor is provided in the storage container 36, and the liquid developer is used according to the detection result of the weight sensor. The storage amount may be detected. Alternatively, the recovery amount of the drum cleaner 19 assumed from the formed image may be counted, and the storage amount of the liquid developer in the storage container 36 may be predicted by the integration count.

Although not illustrated, the control unit 500 includes, for example, a central processing unit (CPU), a read only memory (ROM), and a random access memory (RAM). The ROM stores programs to be executed by the CPU, and the RAM temporarily stores data. In the case of the present embodiment, the control unit 500 can execute “liquid developer supply processing” (see FIG. 8) described later as a program. The control unit 500 controls the pump 49, the high voltage power supply 501, and the drive motor 502 based on the detection result of the liquid level sensor 361 in accordance with the execution of the “liquid developer supply process”. Hereinafter, the “liquid developer supply process” will be described using FIG. 8 with reference to FIG. 7. The “liquid developer supply process” shown in FIG. 8 is repeatedly performed by the control unit 500 at predetermined intervals.

[Liquid developer supply processing]
As shown in FIG. 8, based on the detection result of the liquid level sensor 361, the control unit 500 determines whether the liquid level of the liquid developer in the storage container 36 is equal to or greater than the first liquid level 361A. It is determined (S1). When the liquid level of the liquid developer is equal to or greater than the first liquid level 361 A (Yes in S1), the control unit 500 starts (ON) driving of the pump 49 (S2). In response to the start of driving of the pump 49, the liquid developer stored in the storage container 36 is conveyed to the separation and extraction device 34.

Then, the control unit 500 starts the driving of the drive motor 502 (ON) simultaneously with the start of the driving of the pump 49, and starts the application of the voltage by the high voltage power source 501 (ON) (S3 and S4). In this case, in the separation and extraction device 34, the electrode roller 342 starts rotating in response to the start of driving of the drive motor 502, and the recovery roller 351 rotates in response. Also, an electric field is generated between the electrode roller 342 and the coat electrode member 341 to move the toner to the electrode roller 342 side, and an electric field is generated between the collection roller 351 and the electrode roller 342 to move the toner to the collection roller 351 side. Let Thereby, as described above, the separation and extraction device 34 starts the separation of the toner and the carrier liquid from the liquid developer. The driving of the pump 49, the driving motor 502 and the high voltage power source 501 is continued until the liquid level of the liquid developer in the storage container 36 reaches the second liquid level 361B. After the above-described processes of S2 to S4, the control unit 500 once terminates the “liquid developer supply process” and re-executes (repeats).

On the other hand, when the liquid level of the liquid developer is smaller than the first liquid level 361A (No in S1), the controller 500 develops the liquid in the storage container 36 based on the detection result of the liquid level sensor 361. It is determined whether the liquid level of the agent is equal to or less than the second liquid level 361B (S5). If the liquid level of the liquid developer is equal to or less than the second liquid level 361 B (YES in S5), the control unit 500 stops driving the pump 49 (OFF) (S6). That is, when the liquid developer in the storage container 36 continues to be supplied to the separation and extraction device 34 and the second liquid level becomes 361 B or less, the pump 49 is stopped to move from the storage container 36 to the separation and extraction device 34 Transport of the liquid developer is stopped. When the pump 49 is stopped, the storage amount of the liquid developer in the storage container 36 increases according to the transport of the liquid developer collected by the drum cleaner 19 (see FIG. 2). In this way, the liquid developer is stored in the storage container 36, whereby foreign matter in the liquid developer is precipitated on the bottom surface 36b of the storage container 36 and accumulated in the storage portion 36a.

The control unit 500 stops the driving of the driving motor 502 (OFF) with the stopping of the driving of the pump 49, and further stops the application of the voltage by the high voltage power supply 501 (OFF) (S7 and S8). In this case, in the separation and extraction device 34, the electrode roller 342 and the collection roller 351 stop in response to the drive stop of the drive motor 502. Further, between the electrode roller 342 and the coat electrode member 341, and between the collection roller 351 and the electrode roller 342, the above-described electric field for moving the toner is not generated. Thereby, the separation of the toner and the carrier liquid from the liquid developer by the separation and extraction device 34 is stopped. In this manner, deterioration of the electrode roller 342 can be prevented by preventing the voltage application to the electrode roller 342 having the elastic layer. In addition, it is possible to prevent deterioration due to the electrode roller 342 and the collection roller 351 continuing to rotate. After the processing in S6 to S8, if the liquid level of the liquid developer is higher than the second liquid level 361B (No in S5), the control unit 500 temporarily ends the “liquid developer supply process”. Re-execute (repeat).

In the present embodiment, the flow rate of the liquid developer collected from the drum cleaner 19 is a relatively small flow rate of, for example, 20 cc / min, and the storage container 36 stores the liquid developer for 25 minutes, that is, about 500 cc. it can. And since the pump 49 can supply the liquid developer to the separation and extraction device 34 at a supply amount of 100 cc / min or more, the separation processing of the liquid developer stored in the storage container 36 can be performed in a relatively short time. It is. That is, since the supply amount of the liquid developer that can be supplied to the separation and extraction device 34 is larger than the amount of liquid developer collected by the drum cleaner 19, the separation and extraction device 34 can be stopped. As a result, the driving time of the separation and extraction apparatus 34 can be reduced to about 1/6, and the life of the separation and extraction apparatus 34 can be extended by about 6 times, as compared with the case where the separation and extraction apparatus 34 is constantly driven. Become.

As described above, before the liquid developer collected by the drum cleaner 19 is sent to the separation and extraction device 34, the separation and extraction device 34 is driven by providing the storage container 36 capable of temporarily storing the liquid developer. It becomes possible to control. Thus, the separation and extraction device 34 does not have to be driven at all times, and the deterioration of the electrode roller 342 and the collection roller 351 can be suppressed accordingly, so that the life of the separation and extraction device 34 can be extended.

Other Embodiments
In the case of the embodiment described above, the liquid developer collected by the intermediate transfer roller cleaner 26 and the transfer roller cleaner 27 is held as it is by the intermediate transfer roller cleaner 26 and the transfer roller cleaner 27 because the amount is small. But it is not limited to this. For example, the liquid developer collected by the intermediate transfer roller cleaner 26 or the transfer roller cleaner 27 may be sent to the separation and extraction device 34 via the storage container 36. FIG. 9 shows a configuration in which the liquid developer collected by the intermediate transfer roller cleaner 26 and the transfer roller cleaner 27 is sent to the separation and extraction device 34 via the storage container 36. In the embodiment shown in FIG. 9, the same components as those in the above-described embodiment are denoted by the same reference numerals, and the description will be simplified or omitted.

As shown in FIG. 9, in the case of the present embodiment, the intermediate transfer roller cleaner 26 and the storage container 36 are connected to each other by a middle recovery liquid transport pipe 260. Since the intermediate transfer roller cleaner 26 and the storage container 36 are connected by the intermediate recovery liquid transport pipe 260, the liquid developer collected by the intermediate transfer roller cleaner 26 can be transported to the storage container 36 and stored. On the other hand, the transfer roller cleaner 27 and the storage container 36 are connected to each other by a double recovery liquid transport pipe 270. Since the transfer roller cleaner 27 and the storage container 36 are connected by the second recovery liquid transport pipe 270, the liquid developer collected by the transfer roller cleaner 27 can be transported to the storage container 36 and stored.

The liquid developer collected by the intermediate transfer roller cleaner 26 and the transfer roller cleaner 27 is a small amount as compared with the liquid developer collected by the drum cleaner 19, and the toner concentration (to the total weight of the toner and the carrier liquid). The toner weight ratio) and the viscosity are relatively high. Therefore, the liquid developer collected by the intermediate transfer roller cleaner 26 and the transfer roller cleaner 27 is stored by a screw (not shown) or the like provided in the middle recovery liquid transport pipe 260 or in the second recovery liquid transport pipe 270. It is transported to the container 36. Of course, not limited to this, a pump (not shown) may be provided in the middle of the middle recovery liquid transport pipe 260 and the second recovery liquid transport pipe 270 so as to be able to be transported by this pump.

In addition to the use of a pump, for example, the liquid developer may be transported using its own weight without being provided with a pump if it can be transported by its own weight drop.

The present image forming apparatus is particularly suitable for use with a liquid developer.

The present invention is not limited to the above embodiment, and various changes and modifications can be made without departing from the spirit and scope of the present invention. Accordingly, the following claims are attached to disclose the scope of the present invention.

13: photoconductor (photosensitive drum), 16: developing device (developing device), 19: photoconductor collecting portion (drum cleaner), 20: intermediate transfer member (intermediate transfer roller), 21: transfer member (transfer roller), 26 Intermediate transfer member recovery unit (intermediate transfer roller cleaner) 27 Transfer member recovery unit (transfer roller cleaner) 31 Mixer (mixer) 32 Carrier container (carrier tank) 33 Toner container (toner tank) 34: separation device (separation extraction device) 36: storage container 36b: bottom surface of storage container 45: carrier supply unit (electromagnetic valve) 49: conveyance unit (pump) 100: image forming device 100a: device Body, 190: First transport path (drum collected liquid transport pipe), 360: Second transport path (reserved liquid transport pipe), 361: detection unit (liquid level sensor), 366: discharge port, 500: control section

Claims

A photoconductor,
A developing device for developing an electrostatic latent image formed on the photosensitive member into a toner image with a liquid developer comprising toner and carrier liquid;
A photoreceptor recovery unit for recovering the liquid developer on the photoreceptor;
A separation device for separating the toner and the carrier liquid from the liquid developer;
A storage container capable of storing the liquid developer collected by the photoconductor collection unit;
A first conveyance path capable of conveying the liquid developer collected by the photoconductor collection unit to the storage container;
And a second transport path capable of transporting the liquid developer stored in the storage container to the separation device.
The storage container has a discharge port for discharging the liquid developer through the second transport path, and the discharge port is provided above the bottom surface of the storage container in the gravity direction.
Image forming apparatus.
The lowermost surface of the discharge port is provided at a height of 20 mm or more from the bottom surface of the storage container.
An image forming apparatus according to claim 1.
A transport unit configured to transport the liquid developer stored in the storage container to the separation device via the second transport path;
A detection unit that detects the storage amount of the liquid developer stored in the storage container;
A controller configured to start driving of the transport unit when the storage amount of the liquid developer detected by the detection unit is a first storage amount;
The image forming apparatus according to claim 1.
The control unit stops driving of the transport unit when the storage amount detected by the detection unit is a second storage amount smaller than the first storage amount.
An image forming apparatus according to claim 3.
The separation device separates the toner and the carrier liquid from the liquid developer in response to the application of a voltage.
The control unit starts application of the voltage in response to the start of driving of the transport unit, and stops application of the voltage in response to the stop of driving of the transport unit.
The image forming apparatus according to claim 4.
An intermediate transfer member to which a toner image is transferred from the photosensitive member;
An intermediate transfer member recovery unit for recovering the liquid developer on the intermediate transfer member;
The storage container can store the liquid developer collected by the intermediate transfer member collection unit.
An image forming apparatus according to any one of claims 1 to 5.
A transfer member for transferring the toner image transferred to the intermediate transfer member to a recording material;
A transfer member recovery unit configured to recover the liquid developer on the transfer member;
The storage container can store the liquid developer collected by the transfer member collection unit.
The image forming apparatus according to claim 6.
A toner container for containing toner,
A carrier container containing a carrier liquid;
A mixer which contains a liquid developer, and mixes and disperses the toner supplied from the toner container and the carrier liquid supplied from the carrier container;
A carrier supply unit for supplying a carrier liquid obtained by separating the toner from the liquid developer by the separation device in the carrier container;
An image forming apparatus according to any one of claims 1 to 7.
The storage container is detachably provided to the apparatus body.
An image forming apparatus according to any one of claims 1 to 8.