WO2019235641A1

WO2019235641A1 - Developer supply device, developing device and separation extracting device

Info

Publication number: WO2019235641A1
Application number: PCT/JP2019/022839
Authority: WO
Inventors: 真松尾; 幸寛添田
Original assignee: キヤノン株式会社
Priority date: 2018-06-07
Filing date: 2019-06-04
Publication date: 2019-12-12
Also published as: JP7086733B2; JP2019211708A

Abstract

This developer supply device, which supplies a liquid developer containing a toner and a carrier liquid to a rotating body, is provided to the rotating body so as not to make contact therewith, and comprises: a developer-supporting rotating body that supports a liquid developer; a scraping unit that comes into contact with the developer-supporting rotation body to scrape off the liquid developer on the developer-supporting rotating body; a guide unit that guides the liquid developer, which has been scraped off by the scraper unit, to the rotating body; and a supply blade for supplying the liquid developer to the rotating body. The present invention makes it possible to improve the efficiency of supplying the liquid developer to the developer-supporting rotating body that supports a liquid developer containing a toner and a carrier liquid.

Description

Developer supply device, development device and separation / extraction device

The present invention relates to a developer supply device that supplies a liquid developer containing toner and a carrier liquid, a developing device including the developer supply device, and a separation and extraction device.

Conventionally, an image forming apparatus that forms an image using a liquid developer containing a toner and a carrier liquid is known. In the case of an image forming apparatus using a liquid developer, the liquid developer is supplied from the mixer to the developing device and used for development. In the developing device, the electrostatic latent image formed on the surface of the photosensitive drum is developed into a toner image with a liquid developer carried on a rotating developing roller. The liquid developer carried on the developing roller is supplied by a supply roller in contact with the developing roller (Japanese Patent Laid-Open No. 2010-128287). The supply roller carries and rotates the liquid developer supplied from the supply nozzle, and supplies the liquid developer to the development roller at a contact portion (nip portion) formed between the supply roller and the supply roller.

In an image forming apparatus using a liquid developer, the liquid developer collected from a photosensitive drum or an intermediate transfer roller is transported to a separation / extraction device, and the toner in the liquid developer and the carrier liquid are separated by the separation / extraction device. The carrier liquid can be reused. In the separation and extraction device, the recovered liquid developer is carried on the supply roller, and the liquid developer is supplied from the supply roller to the toner recovery roller that is in contact with the supply roller. When an electric field is applied to the liquid developer carried on the rotating toner collecting roller, the toner and carrier liquid in the liquid developer are separated and extracted.

In the case of the apparatus described in Japanese Patent Application Laid-Open No. 2010-128287, as described above, the liquid developer is supplied from the supply roller that contacts the developing roller (or the separation roller, the same applies hereinafter). Specifically, since the liquid developer carried on the supply roller is divided between the supply roller side and the development roller side, about one half of the liquid developer carried on the supply roller moves to the development roller side. To do.

Incidentally, in the image forming apparatus, in order to increase the speed, that is, to increase the number of recording materials capable of forming an image per unit time, the rotational speed (so-called process speed) of the photosensitive drum and the intermediate transfer roller is increased. In recent years, an increase in speed is also desired in an image forming apparatus using a liquid developer. For this purpose, the supply speed of the liquid developer supplied to the developing roller per unit time is increased by increasing the rotation speed of the supply roller and the developing roller. The amount needs to be increased. However, in the case of the apparatus described in Japanese Patent Application Laid-Open No. 2010-128287, the liquid developer is efficiently supplied to the developing roller because the liquid developer separated from the supply roller is supplied to the developing roller. hard. Therefore, even if the rotation speeds of the supply roller and the developing roller are increased, it is difficult to supply a sufficient amount of liquid developer to the developing roller.

An object of the present invention is to improve the efficiency of supplying a liquid developer to a developer carrying rotor that carries a liquid developer containing toner and carrier liquid.

According to one aspect of the present invention, there is provided a developer supply device for supplying a liquid developer containing toner and a carrier liquid to a rotating body, the developer supplying the liquid developer being arranged in a non-contact manner with the rotating body. A developer-carrying rotator, a scraping part that contacts the developer-carrying rotator and scrapes the liquid developer on the developer-carrying rotator, and the liquid developer scraped by the scraping part is rotated. There is provided a developer supply device that includes a guide portion that guides the body toward the body and includes a supply blade for supplying a liquid developer to the rotating body.

FIG. 1 is a schematic configuration diagram showing a suitable image forming apparatus using the developer supply apparatus of the present embodiment.

FIG. 2 is a sectional view showing the developing device.

FIG. 3 is a sectional view showing the separation and extraction apparatus.

FIG. 4 shows a part of the separation and extraction apparatus shown in FIG. 3, (a) is a diagram for explaining the arrangement of the blade members, and (b) is a diagram for explaining the gaps with the electrode members.

[Image forming apparatus]
First, a suitable image forming apparatus using the developer supply apparatus of this embodiment will be described with reference to FIGS. 1 and 2. An image forming apparatus 100 shown in FIG. 1 is an electrophotographic digital printer that forms an image on a recording material S (sheet material such as paper or an OHP sheet). The image forming apparatus 100 operates based on the image signal, transfers the toner image formed by the image forming unit 12 to the recording material S sequentially conveyed from the

cassettes

11a and 11b, and then fixes the image to obtain an image. . 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 operation of the image forming apparatus 100 is controlled by a control unit (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 the like. Laser light E is irradiated from the laser exposure device 15 on the photosensitive drum 13 whose surface is charged by the charger 14 in accordance with an image signal, and an electrostatic latent image is formed on the photosensitive drum 13. That is, the charger 14 charges the surface of the photosensitive drum 13 to a charging potential having the same polarity as the toner (also referred to as a dark portion potential, for example, −500 V), and the laser exposure device 15 applies an exposed portion potential (bright portion) to the surface of the photosensitive drum 13. An electrostatic latent image is formed at a potential (also referred to as potential, for example, −100 V). The electrostatic latent image is developed into a toner image by the developing device 16. In the case of the present embodiment, the developing device 16 performs development using a liquid developer in which particulate toner is dispersed in a carrier liquid. As the liquid developer, a conventionally used liquid developer may be used.

The liquid developer is generated by mixing and dispersing toner in a carrier liquid at a predetermined ratio (for example, 5 ± 0.5%) in a mixer 31 as a mixer, and is supplied to the developing device 16. Then, the toner is consumed with the development, and the deteriorated carrier liquid is discharged, so that the toner and the carrier liquid are replenished to the mixer 31. The replenishment carrier liquid is accommodated in the carrier tank 32, and the replenishment toner is accommodated in the toner tank 33. Then, in accordance with the toner concentration and the liquid amount of the liquid developer in the mixer 31, the replenishment toner is supplied from the toner tank 33 and the replenishment carrier liquid is supplied from the carrier tank 32 to the mixer 31. The mixer 31 agitates and mixes the supplied carrier liquid and toner, thereby dispersing the toner in the carrier liquid. The replenishment toner is a liquid developer having a toner density higher than the above-described predetermined ratio (for example, 50 ± 1%).

The liquid developer supplied from the mixer 31 to the developing device 16 is coated (supplied) by the developer supplying device 50 in the developing device 16 and used for development. The developing roller 17 carries a liquid developer on its surface and rotates to develop the electrostatic latent image formed on the photosensitive drum 13 into a toner image with the liquid developer. As will be described later, the development of the electrostatic latent image on the photosensitive drum 13 by the developing roller 17 is performed using an electric field. The developing device 16 and the developer supply device 50 will be described later (see FIG. 2). The liquid developer remaining on the developing roller 17 after development is collected in the collection section 16b of the developing device 16.

The toner image formed on the photosensitive drum 13 is primarily transferred to the intermediate transfer roller 20 using an electric field, and is conveyed to a nip portion (secondary transfer portion) formed by the intermediate transfer roller 20 and the transfer roller 21. . The liquid developer remaining on the photosensitive drum 13 after the primary transfer to the intermediate transfer roller 20 is collected by the drum cleaner 18.

The recording material S accommodated in the

cassettes

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

feeding units

22a and 22b configured by conveyance rollers and the like. The registration 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 to the recording material S passing therethrough. The recording material S to which the toner image has been transferred is conveyed to the fixing device 25 by the conveying belt 24, and the toner image transferred to the recording material S is fixed. The recording material S on which the toner image is fixed is discharged out of the apparatus, and the image process is completed. In the present embodiment, the fixing device 25 employs a thermal fixing method. In this method, the fixing device 25 has two rollers that sandwich the recording material S from above and press each other with pressure, and the surface temperature of these two rollers is maintained at about 200 ° C. Thus, 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 a glass transition point at which the toner melts. The toner is fixed on the recording material S by melting the toner.

The intermediate transfer roller 20 and the transfer roller 21 are provided with an intermediate transfer roller cleaner 26 and a transfer roller cleaner 27, respectively. The intermediate transfer roller cleaner 26 collects the liquid developer remaining on the intermediate transfer roller 20 after the secondary transfer from the intermediate transfer roller 20. The transfer roller cleaner 27 collects the liquid developer remaining on the transfer roller 21 after the secondary transfer from the transfer roller 21.

Next, conveyance of the liquid developer in the image forming apparatus 100 will be described. A liquid supply pipe (for example, a pipe or a liquid supply tube) connecting the carrier tank 32 or the toner tank 33 and the mixer 31 has a carrier supply pump 41 as a carrier mixer pump and a toner as a toner mixer pump, respectively. A supply pump 42 is provided. Each of the carrier supply pump 41 and the toner supply pump 42 adjusts the supply amount of the supply carrier liquid supplied to the mixer 31 and the supply amount of the supply toner. The mixer 31 adjusts the concentration of the liquid developer so as to adjust the toner concentration of the liquid developer detected by a toner concentration sensor (not shown) to a predetermined ratio (for example, 5 ± 0.5%). For example, when the toner concentration is higher than a predetermined ratio, the replenishment carrier liquid is supplied from the carrier tank 32 to the mixer 31. When the toner concentration is lower than the predetermined ratio, the replenishment toner is supplied from the toner tank 33 to the mixer 31. To be supplied. Thereby, the toner concentration of the liquid developer in the mixer 31 is adjusted to a predetermined ratio.

From the mixer 31, a liquid developer necessary for development is supplied to the developing device 16 by the developer supply pump 43. The developing device 16 is provided with an unillustrated agent amount detecting device, and the agent amount detecting device detects the amount of the liquid developer in the developing device 16. The liquid developer is supplied to the developing device 16 so that the detection value of the agent amount detection device is a predetermined value (for example, 200 ml) or more. Then, the liquid developer remaining on the developing roller 17 after the development and recovered to the recovery section 16 b of the developing device 16 is returned to the mixer 31 by the circulation pump 44. Alternatively, the liquid developer recovered in the recovery section 16 b of the developing device 16 may be returned to the separation and extraction device 70.

The liquid developer collected by the drum cleaner 18, the intermediate transfer roller cleaner 26, the transfer roller cleaner 27, and the like is conveyed to the separation and extraction device 70 by a pump (not shown). The separation and extraction device 70 is a device that separates the liquid developer into toner and carrier liquid by applying a voltage, and extracts the carrier liquid and toner separately. In other words, the liquid developer collected by the drum cleaner 18 or the like is conveyed to the separation / extraction device 70, and is separated by the separation / extraction device 70 into a carrier liquid and a waste liquid mixed with impurities such as toner and paper powder. The carrier liquid separated by the separation and extraction device 70 is returned to the mixer 31 and reused, for example, and the waste liquid is transported to a waste liquid collection container (see FIG. 3 described later) and discarded.
[Developer]

Next, the developing device 16 will be described with reference to FIG. The developing device 16 includes a developing container 16a that forms a casing, a developing roller 17, a developer supply device 50, an electrode segment 60, a squeeze roller 61, a cleaning roller 62, and a cleaning blade 63. In the following description, the upstream side and the downstream side refer to the upstream side in the rotational direction of the developing roller 17 and the downstream side in the rotational direction of the developing roller 17 unless otherwise specified.

As shown in FIG. 2, a part of the developing container 16a facing the photosensitive drum 13 is opened, and a developing roller 17 is rotatably provided on the developing container 16a so that a part is exposed from the opening. The developing roller 17 as a rotating body is formed in a cylindrical shape having a diameter of 42 mm, for example, and is rotated in the same direction as the photosensitive drum 13 on the surface facing the photosensitive drum 13 (see arrows a and b in the figure). As the developing roller 17, for example, a roller in which an elastic body layer such as a conductive polymer having a thickness of about 5 mm is formed on the outer periphery of a metal inner core such as aluminum or stainless steel is used.

On the opposite side of the surface of the developing roller 17 facing the photosensitive drum 13, an electrode segment 60 as a film forming electrode is spaced from the developing roller 17 by a predetermined gap (for example, 0.4 mm) (hereinafter referred to as film forming GAP). Are arranged opposite each other. A developer supply device 50 is disposed on the upstream side of the electrode segment 60, and the liquid developer is supplied from the developer supply device 50 to the developing roller 17. The liquid developer supplied from the developer supply device 50 passes through the film formation GAP by the rotational force of the developing roller 17. That is, the developer supply device 50 supplies the liquid developer to the developing roller 17 so that the liquid developer is guided from the upstream side of the electrode segment 60 to the film forming GAP. The developer supply device 50 will be described later.

The electrode segment 60 generates an electric field between the electrode segment 60 and the developing roller 17 by applying a voltage of “−500 V” (referred to as a film-forming bias) from a power source (not shown). According to this electric field, the toner in the liquid developer that passes through the film-forming GAP is brought closer to the developing roller 17 side. That is, the electrode segment 60 forms a liquid developer carried on the developing roller 17 and moves the toner to the developing roller 17 side (developing roller side) by applying a voltage.

A squeeze roller 61 is disposed downstream of the electrode segment 60. The squeeze roller 61 is a metal cylindrical member, and is formed of, for example, stainless steel with a diameter of 16 mm. The squeeze roller 61 abuts on the developing roller 17 to form a nip portion N1, and rotates following the rotation of the developing roller 17. Therefore, the liquid developer that has passed through the film formation GAP passes through the nip portion N <b> 1 of the squeeze roller 61. After passing through the nip portion N1, the liquid developer carried on the developing roller 17 is separated into the developing roller 17 side and the squeeze roller 61 side. At that time, of the liquid developer carried on the developing roller 17, the liquid developer containing a larger amount of toner brought closer to the developing roller 17 remains on the developing roller 17 side, and the remaining liquid that is substantially a carrier liquid. The developer is moved to the squeeze roller 61 side. In order to do so, a voltage of “−350 V” (referred to as a concentration bias) is applied to the squeeze roller 61 by a power source (not shown). The liquid developer that does not pass through the nip portion N1 flows down to the bottom of the developing container 16a along the upper surface of the electrode segment 60, and is returned to the mixer 31 (see FIG. 1) from the discharge port.

The developing roller 17 is in contact with the photosensitive drum 13 to form a developing nip portion N2. For example, a voltage of “−300 V” (referred to as a developing bias) is applied to the developing roller 17 from a power source (not shown) while being in contact with the photosensitive drum 13. In this case, the electrostatic latent image on the photosensitive drum 13 is developed into a toner image by the liquid developer carried on the developing roller 17 and passed through the nip portion N1 and conveyed to the developing nip portion N2. That is, the toner in the liquid developer transported to the developing nip portion N2 is selectively attached to the electrostatic latent image on the photosensitive drum 13 by an electric field generated in response to the application of the developing bias (so-called “so-called”). , Electrophoresis).

The liquid developer remaining on the developing roller 17 after development is collected by the cleaning roller 62 and reused. The cleaning roller 62 is a cylindrical member made of metal, and is formed of, for example, stainless steel with a diameter of 16 mm. The cleaning roller 62 is disposed between the developing nip portion N2 and the developer supply device 50 with respect to the rotation direction of the developing roller 17, and is in contact with the developing roller 17 at a contact position. The cleaning roller 62 electrically collects the toner remaining on the developing roller 17 using an electric field. That is, for example, a voltage of “−150 V” (referred to as a cleaning bias) is applied to the cleaning roller 62 from a power source (not shown). Then, the toner remaining on the developing roller 17 moves to the cleaning roller 62 through the carrier liquid. Thus, the cleaning roller 62 collects the toner remaining on the developing roller 17 after development together with the liquid developer.

The toner moved to the cleaning roller 62 is removed by the cleaning blade 63 together with the carrier liquid. The cleaning blade 63 has a metal plate-like member such as stainless steel extending in the rotation axis direction (longitudinal direction) of the cleaning roller 62, and a contact member made of resin or rubber as a free end. On the side. The cleaning blade 63 contacts the cleaning roller 62 on the downstream side of the contact position with the developing roller 17 in the rotation direction of the cleaning roller 62. The cleaning blade 63 contacts the cleaning roller 62 to remove the toner on the cleaning roller 62 together with the carrier liquid. In the present embodiment, for example, the thickness (tip thickness) of the contact member of the cleaning blade 63 is 0.1 mm, and the length (free length) of the contact member is 8 mm. The toner removed by the cleaning blade 63 flows down toward the bottom of the developing container 16a along with the carrier liquid according to gravity, and is returned to the mixer 31 (see FIG. 1) from the discharge port.
[Developer supply device]

Subsequently, the developer supply device 50 will be described. As shown in FIG. 2, the developer supply device 50 includes a supply roller 51, a guide blade 52, and a developer storage tray 53. The developer storage tray 53 as a storage unit temporarily stores the liquid developer supplied to the developing roller 17. The developer storage tray 53 stores an amount of liquid developer that can be pumped up by the supply roller 51. That is, the liquid developer is supplied to the developer storage tray 53 from the mixer 31 (see FIG. 1) so that the liquid level of the liquid developer in the developer storage tray 53 can be pumped up by the supply roller 51. Supplied.

The supply roller 51 is formed in a cylindrical shape with a metal such as stainless steel, and is rotatable in the developer storage tray 53 so that a part of the outer peripheral surface is immersed in the liquid developer stored in the developer storage tray 53. Is provided. The supply roller 51 serving as a developer carrying rotator can be rotated by a motor (not shown) to draw up the liquid developer from the developer storage tray 53 and carry and rotate the pumped liquid developer. In the present embodiment, the supply roller 51 is disposed so as to face the developing roller 17 in a non-contact manner, and is rotated in the opposite direction to the developing roller 17 on the surface facing the developing roller 17 (see arrows b and c in the figure). Note that the amount of liquid developer supplied from the mixer 31 to the developer storage tray 53 may be larger than the amount of liquid pumped from the developer storage tray 53 by the supply roller 51. In this case, the liquid developer overflowing from the developer storage tray 53 flows down toward the bottom of the developing container 16a according to gravity, and is returned to the mixer 31 from the discharge port.

In the case of this embodiment, the supply roller 51 is spaced apart from the developing roller 17. Therefore, in order to supply the liquid developer pumped up from the developer storage tray 53 from the supply roller 51 to the development roller 17, a guide blade 52 as a guide member is provided so as to bridge the supply roller 51 and the development roller 17. It has been. The guide blade 52 is a metal plate-like member such as stainless steel that extends in the rotation axis direction (longitudinal direction) of the supply roller 51, and includes a scraping portion 52a and a guide portion 52b. The scraping unit 52 a contacts the supply roller 51 at the contact position w, thereby scraping off the liquid developer carried on the supply roller 51. In the case of the present embodiment, the guide blade 52 is disposed such that the scraping portion 52 a comes into contact with the supply roller 51 from the direction opposite to the rotation direction of the supply roller 51 (counter direction). The counter direction is a direction in which the direction toward the tip of the scraping portion 52 a that contacts the supply roller 51 in the guide blade 52 is opposite to the tangential direction along the rotation direction of the supply roller 51. Specifically, the guide blade 52 has a straight line k that passes through the scraping portion 52 a and a straight line j that is a tangent to the supply roller 51 at the contact position w and is downstream of the supply roller 51 in the rotation direction. The contact is made from the counter direction where the formed angle θ is an acute angle.

The guide blade 52 guides the liquid developer to the upstream side of the electrode segment 60. The liquid developer scraped off by the scraping portion 52a is supplied from the scraping portion 52a to the developing roller 17 through the guide portion 52b. In other words, the guide unit 52b guides the liquid developer scraped by the scraping unit 52a toward the developing roller 17. The guide portion 52b is not in contact with the developing roller 17. In the present embodiment, the scraping portion 52a and the guide portion 52b are integrally formed, and the liquid developer that is scraped uniformly in the longitudinal direction by the scraping portion 52a travels along the upper surface of the guide portion 52b, and the developing roller 17. To be supplied. At this time, when the liquid developer is guided to the gap (film formation GAP) between the developing roller 17 and the electrode segment 60 by the guide portion 52b, the liquid developer can be effectively supplied to the developing roller 17. In view of this, it is preferable that the leading end of the guiding blade 52 on the side of the guiding portion 52b is positioned in the vicinity of the inlet on the upstream side of the film forming GAP without being brought into contact with the developing roller 17.

Further, in the developing roller 17, both ends of the developing roller 17 in the film forming GAP in the rotation axis direction are sealed so that the liquid developer does not leak. Therefore, the liquid developer guided to the film forming GAP by the guide blade 52 is conveyed downstream in the film forming GAP as the developing roller 17 rotates. A part of the liquid developer guided by the guide blade 52 does not enter the film forming GAP. In this case, the liquid developer overflowing from the film formation GAP flows down toward the bottom of the developing container 16a according to gravity, and is returned to the mixer 31 from the discharge port.

The guide blade 52 preferably has a longitudinal length equal to or greater than the longitudinal length of the supply roller 51 capable of carrying the liquid developer in the supply roller 51. Then, the guide blade 52 scrapes the liquid developer uniformly from the supply roller 51 in the longitudinal direction, so that the liquid developer is reliably supplied to the film forming GAP. Further, the supply roller 51 and the guide blade 52 are not limited to those using stainless steel, and any material can be used as long as the liquid developer carried on the supply roller 51 can be scraped efficiently without waste. Good. For example, the supply roller 51 may have rubber or resin on the outer periphery of a metal core, and the guide blade 52 may be a plate member formed of rubber or resin.

As described above, in the present embodiment, the liquid developer is carried on the supply roller 51 that rotates in the developer supply device 50, and the liquid developer is scraped from the supply roller 51 by the guide blade 52. A liquid developer is supplied. Since the supply roller 51 and the developing roller 17 are spaced apart from each other, the guide blade 52 is provided so as to bridge between the separated supply roller 51 and the developing roller 17. The liquid developer is guided to the developing roller 17. In the present embodiment, a part of the liquid developer carried on the supply roller 51 is not completely removed and supplied to the developing roller 17, but the liquid developer scraped off by the guide blade 52 is only applied to the developing roller 17. Supplied. The guide blade 52 can scrape most of the liquid developer carried on the supply roller 51 and can evenly scrape in the longitudinal direction. Therefore, the supply of the liquid developer to the developing roller 17 by the guide blade 52 can supply the liquid developer more efficiently than the supply of the liquid developer by the guide blade 52. Accordingly, if the rotation speeds of the supply roller 51 and the developing roller 17 are increased, it becomes easy to increase the supply amount of the liquid developer supplied to the developing roller 17 per unit time.
[Separation and extraction device]

In the above description, the case where the developer supply device 50 of the present embodiment is applied to the developing device 16 has been described as an example. However, the developer supply device 50 described above is not limited to being applied to the developing device 16 and is separated and extracted. You may apply to the apparatus 70. FIG. Therefore, a case where the developer supply device 50 is applied to the separation and extraction device 70 will be described with reference to FIGS. 3 to 4B with reference to FIG. In the following description, the same components as those applied to the developing device 16 are denoted by the same reference numerals, and description and illustration are omitted or simplified. In the following description, unless otherwise specified, the upstream side and the downstream side mean the upstream side in the rotation direction of the separation roller 71 and the downstream side in the rotation direction of the separation roller 71, respectively.

The configuration of the separation and extraction apparatus 70 of this embodiment will be described. As shown in FIG. 3, the separation and extraction device 70 of the present embodiment includes, in addition to the developer supply device 50, a separation roller 71, an electrode segment 60 as a film forming electrode, a carrier liquid collection container 84, and a toner collection device 80. Have.

The separation roller 71 as a rotating body is a conductive roller in which a urethane rubber elastic layer is integrally formed on the outer periphery of a core metal having an outer diameter of φ40 mm made of stainless steel, for example. The separation roller 71 is driven by a motor (not shown) and is rotated in a predetermined rotation direction (the direction of arrow d in FIG. 3). The electrode segment 60 is disposed through a gap with the separation roller 71. The electrode segment 60 disposed with a gap between the separation roller 71 and the separation roller 71 is formed of a conductive material at least on the surface through which the liquid developer passes. The electrode segment 60 is made of, for example, stainless steel, and a portion through which the liquid developer passes has a shape facing a part of the separation roller 71, and a surface facing the separation roller 71 is a predetermined distance from the surface of the separation roller 71. It has a curved shape so as to maintain (that is, a gap). This predetermined distance is, for example, about 0.2 to 0.8 mm.

An electric field is applied to the electrode segment 60 and the separation roller 71 by a power source (not shown) so that the toner in the liquid developer passing through the gap between the electrode segment 60 and the separation roller 71 is drawn to the separation roller 71 side (separation roller side). A voltage is applied to generate. In this embodiment, for example, a voltage of “−300 V” is applied to the separation roller 71 and a voltage of “−1000 V” is applied to the electrode segment 60. As a result, the toner is brought to the separation roller 71 side while the liquid developer passes through the gap. After passing through the gap, a part of the liquid developer carried on the separation roller 71 is separated from the separation roller 71 according to gravity. At that time, of the liquid developer carried on the separation roller 71, the liquid developer (waste liquid) containing a larger amount of toner remains on the separation roller 71 side, and the remaining liquid developer that is substantially the carrier liquid is separated. Separate from the roller 71. Thus, the toner and the carrier liquid are separated. The separated carrier liquid is discharged to the carrier liquid recovery container 84 and returned to the mixer 31 or the like from the carrier liquid recovery container 84 for reuse.

On the other hand, the waste liquid remaining on the separation roller 71 side after passing through the gap is recovered by the toner recovery device 80. The toner recovery device 80 is disposed on the downstream side of the electrode segment 60 and recovers a liquid developer (hereinafter referred to as waste liquid) carried on the separation roller 71. The toner recovery device 80 includes a recovery roller 81, a blade member 82, and a waste liquid recovery container 83.

The collection roller 81 is a conductive roller having an outer diameter of φ20 mm made of, for example, solid stainless steel, and is disposed so as to contact the separation roller 71. The collection roller 81 is in contact with the separation roller 71 and is driven to rotate in the same direction as the rotation direction of the separation roller 71 (direction of arrow e in FIG. 3) on the surface facing the separation roller 71. A voltage is applied to the separation roller 71 and the collection roller 81 by a power source (not shown) so that an electric field for moving the toner toward the collection roller 81 is generated between the collection roller 81 and the separation roller 71. In this embodiment, for example, a voltage of “−300 V” is applied to the separation roller 71, and a voltage of “−200 V” is applied to the collection roller 81. As a result, the toner in the waste liquid carried on the separation roller 71 and conveyed to the collection roller 81 is moved from the separation roller 71 to the collection roller 81 together with the carrier liquid.

The blade member 82 contacts the collection roller 81 and removes the waste liquid from the collection roller 81. The waste liquid removed by the blade member 82 is stored in the waste liquid collection container 83 and then discarded. The blade member 82 is disposed on the downstream side in the rotation direction of the collection roller 81 with respect to the contact position between the separation roller 71 and the collection roller 81 and in contact with the collection roller 81 in the counter direction. The counter direction is a direction in which the direction of the tip portion of the blade member 82 that contacts the collection roller 81 is opposite to the tangential direction along the rotation direction of the collection roller 81. The blade member 82 is a plate-like member extending along the rotation axis direction (longitudinal direction) of the collection roller 81, and for example, stainless steel is used. The member for removing the waste liquid containing toner from the collection roller 81 is not limited to the blade member 82 described above, and may be a brush or the like.

In order to supply the liquid developer to the separation roller 71, the developer supply device 50 described above can also be applied to the separation and extraction device 70. As already described, the developer supply device 50 includes the supply roller 51, the guide blade 52, and the developer storage tray 53. However, when applied to the separation and extraction device 70, the developer storage tray 53 stores the liquid developer collected by the drum cleaner 18, the intermediate transfer roller cleaner 26, the transfer roller cleaner 27, etc. (see FIG. 1). . The supply roller 51 is rotatably provided so that a part of the outer peripheral surface is immersed in the liquid developer stored in the developer storage tray 53. The supply roller 51 can draw up the liquid developer from the developer storage tray 53 and can carry and rotate the pumped liquid developer. The supply roller 51 is disposed so as to face the separation roller 71 in a non-contact manner, and is rotated in the same direction as the separation roller 71 on the surface facing the separation roller 71 (see arrows c and d in the figure).

In order to supply the liquid developer pumped up from the developer storage tray 53 from the supply roller 51 to the separation roller 71, a guide blade 52 as a guide member is provided so as to bridge the supply roller 51 and the separation roller 71. Yes. The guide blade 52 has a scraping part 52a and a guide part 52b. The scraping unit 52 a contacts the supply roller 51 at the contact position w, thereby scraping off the liquid developer on the supply roller 51 (on the developer-carrying rotating body) carried by the supply roller 51. The liquid developer scraped off by the scraping portion 52a is supplied from the scraping portion 52a to the separation roller 71 through the guide portion 52b. That is, the liquid developer uniformly scraped in the longitudinal direction by the scraping portion 52a is supplied to the separation roller 71 along the upper surface of the guide portion 52b.

The guide position of the liquid developer on the separation roller 71 by the guide blade 52 will be described with reference to FIG. As shown in FIG. 4A, the guide position m is located above the horizontal line p passing through the rotation center of the separation roller 71 in the gravitational direction and from a vertical line o passing through the rotation center of the separation roller 71. It may be in a range 71 a up to the tangent line q of the outermost diameter point of the 50-side separation roller 71. In this case, the electrode segment 60 is disposed below the guide blade 52 (specifically, the tip on the guide portion 52b side) in the gravity direction. Thus, even if the guide position m varies, the liquid developer is guided to the gap with the electrode segment 60 by the rotation of the separation roller 71. The guide position m of the separation roller 71 where the guide blade 52 guides the liquid developer is preferably near the entrance of the gap between the electrode segment 60 and the separation roller 71. That is, the guide blade 52 is positioned near the entrance of the gap between the separation roller 71 and the electrode segment 60 so that the guide blade 52 guides the liquid developer into the gap between the separation roller 71 and the electrode segment 60. Is more preferable.

Here, the stop operation of the separation and extraction apparatus 70 will be described with reference to FIG. When the separation operation by the separation and extraction device 70 is stopped, the liquid developer supplied from the supply roller 51, the liquid developer in the gap between the electrode segment 60 and the separation roller 71, the waste liquid after collecting the carrier liquid, Must be prevented from being mixed into the carrier liquid recovery container 84. For this purpose, first, the supply operation of the liquid developer from the developer supply device 50 is stopped. In order to stop the supply operation of the liquid developer, the rotation of the supply roller 51 is stopped. When the rotation of the supply roller 51 is stopped, the liquid developer carried on the supply roller 51 flows down on the surface of the supply roller 51 according to gravity. Then, the liquid developer including the liquid developer that has flowed through the guide blade 52 into the gap is discharged from the gap as the separation roller 71 rotates, and the waste liquid on the separation roller 71 is collected by the collection roller 81. Then, the rotation of the separation roller 71 and the collection roller 81 is stopped. By doing so, it is possible to prevent the liquid developer and the waste liquid before separating the toner and the carrier liquid from entering the carrier liquid recovery container 84.

As shown in FIG. 4B, the electrode segment 60 has a developer guiding portion 601 for guiding the liquid developer guided by the guide blade 52 to the gap in the vicinity of the entrance of the gap with the separation roller 71. It may be formed. In this case, the liquid developer can be reliably guided to the gap by the guide blade 52 without strictly positioning the tip of the guide blade 52 on the guide portion 52b side in the vicinity of the gap. In order to more reliably guide the liquid developer into the gap, the area of the developer guiding portion 601 may be increased. However, the larger the developer guiding portion 601 is, the easier the liquid developer guided by the guide blade 52 is accumulated in the developer guiding portion 601. Therefore, if the area of the developer guiding portion 601 is excessively increased, all of the liquid developer accumulated in the developer guiding portion 601 from the rotation stop when the supply roller 51 is stopped to stop the supply of the liquid developer. There may be a time lag before the flow ends. Therefore, when the separation operation by the separation and extraction device 70 is stopped, it is necessary to stop the rotation of the separation roller 71 and the collection roller 81 in a state where the liquid developer accumulated in the developer guiding portion 601 is further exhausted. Otherwise, it is difficult to prevent the liquid developer and the waste liquid before separating the toner and the carrier liquid from entering the carrier liquid collection container 84 as described above.

As described above, the developer supply device 50 described above may be applied to the separation and extraction device 70. Even in such a case, the supply of the liquid developer to the separation roller 71 by the guide blade 52 can provide an effect that the liquid developer can be supplied more efficiently than the supply of the liquid developer by all means. .
In the above-described embodiment, the case where a liquid developer that has been conventionally used is used as the liquid developer used in the image forming apparatus 100 is described as an example, but the present invention is not limited thereto. For example, as the liquid developer used in the image forming apparatus 100, an ultraviolet curable liquid developer that is cured by ultraviolet rays may be used.

According to the present invention, a developer supply device, a development device, and separation / extraction that can improve the efficiency of supplying a liquid developer to a developer carrying rotor that carries a liquid developer containing toner and a carrier liquid. An apparatus is provided.

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. Therefore, in order to make the scope of the present invention public, the following claims are attached.

This application claims priority on the basis of Japanese Patent Application No. 2018-109834 filed on Jun. 7, 2018, the entire contents of which are incorporated herein by reference.

Claims

A developer supply device for supplying a liquid developer containing toner and carrier liquid to a rotating body,
A developer-carrying rotator that is disposed in non-contact with the rotator and carries a liquid developer;
A scraping unit that contacts the developer carrying rotator and scrapes off the liquid developer on the developer carrying rotator, and guides the liquid developer scraped by the scraping unit toward the rotator. A supply blade for supplying a liquid developer to the rotating body,
A developer supply apparatus comprising:
The developer supply device according to claim 1,
The scraping portion and the guide portion are a developer supply device formed integrally.
The developer supply device according to claim 1 or 2,
Of the tangent lines of the developer carrying rotator at the contact position where the scraping part abuts the developer carrying rotator, the angle formed on the downstream side in the rotation direction of the developer carrying rotator is an acute angle. A developer supply device in which the supply blade is disposed.
The developer supply device according to any one of claims 1 to 3,
A storage section for storing the liquid developer;
The developer carrying rotator is a developer supply device that carries the liquid developer stored in the storage section.
The developer supply device according to any one of claims 1 to 4,
The developer supply apparatus, wherein the liquid developer is an ultraviolet curable liquid developer that is cured by ultraviolet rays.
A developing device,
A developing roller carrying a liquid developer for developing the electrostatic latent image formed on the photoreceptor using a liquid developer containing toner and a carrier;
A developer supply device for supplying a liquid developer to the developing roller;
With
The developer supply device includes:
A developer-carrying rotating body that is arranged in a non-contact manner with the developing roller and carries a liquid developer;
A scraping portion that contacts the developer carrying rotator and scrapes the liquid developer on the developer carrying rotator, and guides the liquid developer scraped by the scraping portion toward the developing roller. A supply blade for supplying a liquid developer to the developing roller,
A developing device.
The developing device according to claim 6,
The developing device in which the scraping portion and the guide portion are integrally formed.
The developing device according to claim 6 or 7,
Of the tangent lines of the developer carrying rotator at the contact position where the scraping part abuts the developer carrying rotator, the angle formed on the downstream side in the rotation direction of the developer carrying rotator is an acute angle. A developing device in which the supply blade is disposed.
The developing device according to any one of claims 6 to 8,
A storage section for storing the liquid developer;
The developer carrying rotator is a developing device that carries the liquid developer stored in the storage section.
The developing device according to any one of claims 6 to 9,
A film forming electrode that is disposed with a gap with respect to the developing roller, forms a liquid developer carried on the developing roller, and moves toner toward the developing roller by applying a voltage;
A developing device in which the supply blade is arranged so that the liquid developer is guided to an entrance of a gap between the developing roller and the film forming electrode by the guide portion.
The developing device according to any one of claims 6 to 10,
The developing device, wherein the supply blade is disposed below the film forming electrode in the direction of gravity.
The developing device according to any one of claims 6 to 11,
The developing device, wherein the liquid developer is an ultraviolet curable liquid developer that is cured by ultraviolet rays.
A separation and extraction device,
A separation roller that carries a liquid developer containing toner and carrier liquid, and separates the liquid developer into toner and carrier liquid by application of voltage;
A developer supply device for supplying a liquid developer to the separation roller;
With
The developer supply device includes:
A developer-carrying rotating body that is disposed in a non-contact manner with the separation roller and carries a liquid developer;
A scraping portion that contacts the developer carrying rotator and scrapes off the liquid developer on the developer carrying rotator, and guides the liquid developer scraped by the scraping portion toward the separation roller. A supply blade for supplying a liquid developer to the separation roller,
Separation and extraction device having.
The separation and extraction device according to claim 13,
The scraping unit and the guide unit are separated and extracted as a single unit.
The separation and extraction device according to claim 13 or 14,
Of the tangent lines of the developer carrying rotator at the contact position where the scraping part abuts the developer carrying rotator, the angle formed on the downstream side in the rotation direction of the developer carrying rotator is an acute angle. A separation and extraction device in which the supply blade is arranged.
The separation / extraction apparatus according to any one of claims 13 to 15,
A storage unit for storing the liquid developer;
The developer carrying rotator is a separation and extraction device that carries the liquid developer stored in the storage section.
The separation and extraction device according to any one of claims 13 to 16,
Further comprising a film-forming electrode that is disposed with a gap with respect to the separation roller, forms a liquid developer carried on the separation roller, and moves toner toward the separation roller by application of a voltage;
A separation and extraction device in which the supply blade is arranged so that the liquid developer is guided to an entrance of a gap between the separation roller and the film forming electrode by the guide portion.
The separation / extraction apparatus according to any one of claims 13 to 17,
The supply and extraction blade is a separation and extraction device arranged above the film-forming electrode in the direction of gravity.
The separation / extraction apparatus according to any one of claims 13 to 18,
The separation / extraction apparatus, wherein the liquid developer is an ultraviolet curable liquid developer that is cured by ultraviolet rays.