JP2023069306A - developing device - Google Patents

Abstract

To provide a developing device which solves problems caused by air flow generated by rotation of a conveyor screw, for example, to suppress excessive discharge of developer.SOLUTION: A developing device comprises: a development housing which stores developer; two conveyance screws for circulating and conveying the developer in the development housing; a first chamber in which the developer is guided in a first direction by rotation of one of the two conveyance screws; and a second chamber in which the developer is guided in the opposite direction from the first direction by rotation of the other one of the two conveyance screws, with a partition wall partitioning the first chamber and the second chamber having openings which make the first chamber and the second chamber communicate with each other.SELECTED DRAWING: Figure 5

Description

The present invention relates to a developing device.

For example, in Patent Document 1, a conveying member is disposed between the upstream end and the downstream end of a communication port that delivers developer from the first chamber to the second chamber, and vertically above the conveying member in the first chamber. The developing device is provided with a wall member extending across the width direction intersecting with the direction of the rotation axis of the developing device, and the wall member has a blocking wall portion for blocking an air flow generated as the conveying member rotates.

JP 2019-109359 A

However, in the above-described developing device, since the airflow (airflow) generated by the rotation of the conveying screw (conveying member) is blocked in the vicinity of the communication port, the flow rate of the airflow in the first chamber (first chamber) is When is large, it is difficult to reduce the flow rate of the air flow to a desired flow rate at the blocking wall portion, and there is a risk that the developer may be excessively discharged to the outside by the air flow. Alternatively, the developer may scatter into the air in the first chamber and leak out through the gap between the developing sleeve and the developing housing.

SUMMARY OF THE INVENTION Accordingly, it is an object of one aspect of the present invention to solve the problem caused by the air flow generated by the rotation of the conveying screw, for example, to provide a developing device capable of suppressing excessive discharge of the developer.

A developing device according to an aspect of the present invention includes a development housing containing a developer, two transport screws for circulating and transporting the developer in the development housing, and one of the two transport screws rotating. a first chamber for guiding the developer in a first direction; and a second chamber for guiding the developer in a direction opposite to the first direction by rotation of the other of the two conveying screws, wherein the first chamber and the A partition wall that separates the second chamber has an opening that communicates the first chamber and the second chamber.

1 is a schematic cross-sectional view showing an image forming apparatus; FIG. 3 is a perspective view showing a developing device and a toner cartridge; FIG. 3 is a perspective view showing the internal configuration of the developing device; FIG. 3 is a cross-sectional view of the developing device; FIG. FIG. 3 is a perspective view of the developing device showing a flow diverting portion; 4 is a cross-sectional view of the developing device showing a flow diverting portion; FIG. FIG. 4 is a side view of the developing device showing a flow diverting portion; FIG. 3 is a perspective view of the developing device showing a flow diverting portion; It is a side schematic diagram which shows the pitch of adjacent opening parts. FIG. 5 is a cross-sectional view of a developing device showing a first modification of the flow dividing portion; FIG. 11 is a side view of the developing device showing a first modification of the flow dividing portion; FIG. 11 is a perspective view of a developing device showing a second modification of the flow dividing portion; FIG. 11 is a cross-sectional view of the developing device showing a second modification of the flow dividing portion; 4 is a perspective view of the upper surface cover member of the developing device as seen from the back side; FIG.

Hereinafter, each embodiment of the present invention will be described with reference to the drawings. In the present specification and drawings, the same or equivalent elements are denoted by the same reference numerals to omit redundant description, and elements that are not directly related to the present invention may be omitted from the drawings. Furthermore, the forms of the components shown in these embodiments are merely examples, and the present invention is not limited to these forms.

An image forming apparatus 100 including a developing device 200 according to one aspect of the present invention will be described below with reference to FIG. The image forming apparatus 100 is, for example, a multifunction machine having a copying function, a printer function, a scanner function, a facsimile function, and the like. FIG. 1 is a schematic cross-sectional view showing an image forming apparatus 100. As shown in FIG. In the following description, the side on which the image forming apparatus 100 is placed is defined as the lower side, the opposite side is defined as the upper side, the side where the manual feed tray 139 is provided is defined as the right side, and the opposite side is defined as the left side.

The image forming apparatus 100 includes an apparatus body 110 and an image reading device 120 . The image forming apparatus 100 forms a monochromatic or multicolored image on a predetermined sheet based on image data read by the image reading device 120 or image data transmitted from an external terminal.

The image reading device 120 includes a document table 121 made of a transparent material, a document pressing cover 122 attached to the document table 121 so as to be openable and closable, a light source, a plurality of mirrors, an imaging lens, a line sensor, and the like. and an image reading unit 123 that generates image data based on the image of the surface of the document. On the front side of document table 121, a display operation unit (not shown) is provided for receiving input operations by the user. The display operation unit is, for example, an operation panel such as a touch panel and operation buttons.

The apparatus body 110 has an image forming section 130 . The image forming section 130 forms an image with toner supplied from the toner cartridge 150 . The image forming section 130 includes a photosensitive drum 131, a charger 132, an exposure unit 133, a developing device 200, a cleaner unit 134, an intermediate transfer belt unit 135, a transfer roller 136, a fixing unit 137, and the like. .

The image data handled by the image forming apparatus 100 corresponds to four color images of black (K), cyan (C), magenta (M), and yellow (Y). For this reason, four photoreceptor drums 131, chargers 132, developing devices 200, and cleaner units 134 are provided so as to form four types of latent images corresponding to each color, thereby forming four image forming stations. is configured. Four toner cartridges 150 are provided so as to supply toner corresponding to each image forming station.

The photoreceptor drum 131 is an electrostatic latent image carrier in which a photosensitive layer is formed on the surface of a conductive cylindrical base. The charger 132 charges the surface of the photosensitive drum 131 to a predetermined potential. The exposure unit 133 is a laser scanning unit including a laser emitting section, a reflecting mirror, and the like. The exposure unit 133 forms an electrostatic latent image corresponding to the image data on the surface of the photosensitive drum 131 by exposing the charged surface of the photosensitive drum 131 . The developing device 200 visualizes the electrostatic latent image formed on the surface of the photosensitive drum 131 with toner of four colors. The cleaner unit 134 removes and collects toner remaining on the surface of the photosensitive drum 131 after development and image transfer.

The intermediate transfer belt unit 135 includes an intermediate transfer belt 135a, a drive roller 135b, a driven roller 135c, four intermediate transfer rollers 135d, and the like. The intermediate transfer belt unit 135 is arranged above the photosensitive drum 131 . The intermediate transfer belt 135a is provided so as to be in contact with each photoreceptor drum 131, and each color toner image formed on the corresponding photoreceptor drum 131 is sequentially superimposed on the intermediate transfer belt 135a using each intermediate transfer roller 135d. A toner image is formed on the intermediate transfer belt 135a.

The transfer roller 136 is arranged in the vicinity of the drive roller 135b on the first transport path L1, which will be described later. The toner image formed on the intermediate transfer belt 135a is transferred to the paper by passing the paper through the nip area between the transfer roller 136 and the intermediate transfer belt 135a. The transfer roller 136 includes, for example, a metal core such as stainless steel or iron, and a conductive sponge elastic layer is formed on the core metal using carbon, an ion-conductive filler, an ion-conductive base polymer, or the like. A foam layer (foam cells) is formed on the surface layer of the sponge elastic layer.

The fixing unit 137 includes a heat roller 137a and a pressure roller 137b. The fixing unit 137 is arranged above the transfer roller 136, in other words, on the downstream side in the sheet conveying direction in the first conveying path L1, which will be described later. As the paper passes through the nip area between the heat roller 137a and the pressure roller 137b, the toner image transferred to the paper is melted, mixed, and pressed, and the toner image is thermally fixed to the paper.

Inside the apparatus main body 110 , a first transport unit is provided for transporting the paper transported from the paper feed tray 138 , the manual feed tray 139 , etc., to the paper output tray 141 via the registration roller 140 , the transfer roller 136 , and the fixing unit 137 . A path L1 is formed. Further, in the apparatus main body 110, when double-sided printing is performed on a sheet of paper, after single-sided printing has been completed and the sheet of paper has passed through the fixing unit 137, it is placed upstream of the transfer roller 136 in the sheet conveying direction. A second transport path L2 is formed for returning to the first transport path L1. A plurality of conveying rollers 142 are appropriately provided in the first conveying path L1 and the second conveying path L2 for providing auxiliary driving force to the paper.

An outline of the developing device 200 will be described. FIG. 2 is a perspective view showing the developing device 200 and the toner cartridge 150. As shown in FIG. FIG. 2 shows a perspective view of the developing device 200 and the toner cartridge 150 viewed obliquely from above on the rear side. FIG. 3 is a perspective view showing the internal configuration of the developing device 200. As shown in FIG. FIG. 3 shows a view from which an upper cover member 210b and a housing cover 273, which will be described later, of the developing device 200 are removed. In FIG. 3, the illustration of the branching section 300, which will be described later, is omitted. FIG. 4 is a cross-sectional view of the developing device 200. As shown in FIG. FIG. 4 shows a cross-sectional view taken in a direction orthogonal to the axial direction of the conveying screw of the developing device 200. As shown in FIG. FIGS. 2 to 4 show a state in which no developer D is stored in a development housing 210, which will be described later. The developer D is a two-component developer containing toner T and carrier C as main components.

The developing device 200 is a trickle developing type developing device. In the trickle development type developing device 200, when developing the electrostatic latent image on the photosensitive drum 131 with the two-component developer D, the deteriorated carrier C is replaced with a new carrier C. FIG. In the trickle development type developing device, the carrier C is added little by little when the toner T is replenished to the development housing 210, which will be described later, and the surplus developer D is discharged to gradually replace the developer D. there is

As shown in FIG. 2 , the rear end side of the developing device 200 is connected to the rear end side of the toner cartridge 150 via the replenishment portion 160 to receive the toner T and the carrier C from the toner cartridge 150 . The toner cartridge 150 is detachably attached to a cartridge mounting portion 150 a arranged above the developing device 200 .

The developing device 200 includes a developing housing 210 , a first conveying screw 220 , a second conveying screw 230 , a developing roller 240 , a layer regulation blade 250 , a receiving section 260 and a discharging section 270 .

The development housing 210 accommodates the developer D and holds each component of the development device 200 . The development housing 210 is a long housing extending in the front-rear direction. The developer housing 210 mainly has a base frame 210a with an open top and a top cover member 210b (see FIG. 4). A top cover member 210b is attached to the base frame 210a so as to close the opening on the top surface of the base frame 210a. Toner T contained in developer D housed inside development housing 210 is supplied to photoreceptor drum 131 via development roller 240 .

As shown in FIG. 3, the developer housing 210 rotatably supports two transport screws for circulating and transporting the developer D. As shown in FIG. One of the two conveying screws is defined as first conveying screw 220 and the other of the two conveying screws is defined as second conveying screw 230 .

The development housing 210 includes a first chamber 211 that guides the developer D forward (first direction) by the rotation of the first conveying screw 220 and backward (opposite to the first direction) by the rotation of the second conveying screw 230 . and a second chamber 212 for introducing the developer D into the chamber. The first chamber 211 and the second chamber 212 are arranged side by side in the left-right direction. The first chamber 211 is positioned to the left of the second chamber 212 . Also, the second chamber 212 is formed to be higher than the first chamber 211 . The second chamber 212 has a vent 212a on its upper wall. A filter 212b is provided in the vent 212a. The filter 212b is made of a material such as non-woven fabric, for example.

The first conveying screw 220 is arranged in the first chamber 211 with the front-rear direction as its axial direction. The first conveying screw 220 has a blade portion 220a spirally wound in one direction around the rotation axis. The first conveying screw 220 is rotationally driven in one direction by power from a driving mechanism (not shown), and the blade portion 220a enables the developer D to be pushed forward.

In addition, the second conveying screw 230 is arranged in the second chamber 212 with the front-rear direction as the axial direction. The second conveying screw 230 has a blade portion 230a spirally wound in one direction around the rotation axis. The second conveying screw 230 is driven to rotate in the other direction by power from a drive mechanism (not shown), allowing the blade portion 230a to push out the developer D backward.

As shown in FIGS. 3 and 4, the developer housing 210 has a partition wall 213 that separates the first chamber 211 and the second chamber 212 from each other. The partition wall 213 is a wall body that divides the interior of the developing housing 210 into left and right sides and extends in the front-rear direction. The partition wall 213 is arranged with a predetermined gap from the front wall of the developing housing 210 . That is, between the front wall of the developing housing 210 and the partition wall 213, a first flow port A1 for the developer D is provided. Further, it is arranged with a predetermined gap from the rear wall of the developing housing 210 . That is, a second flow port A2 for the developer D is provided between the rear wall of the developing housing 210 and the partition wall 213 .

In the above configuration, the power from the driving mechanism (not shown) rotates the first conveying screw 220 and the second conveying screw 230, so that the developer D in the first chamber 211 moves to the first conveying screw 220. The air is pushed forward by the blade portion 220a and is allowed to flow into the second chamber 212 through the first flow port A1. Further, the developer D in the second chamber 212 is pushed rearward by the blade portion 230a of the second conveying screw 230 and is allowed to flow into the first chamber 211 through the second flow port A2. Thereby, the developer D can be circulated and transported between the first chamber 211 and the second chamber 212 .

As shown in FIG. 4, the developing roller 240 is a long roller that carries the developer D housed in the developing housing 210 . The developing roller 240 is arranged in the second chamber 212 with the front-rear direction as the axial direction. The developing roller 240 is arranged above the second conveying screw 230 .

The developing roller 240 includes a magnet roller 240a having a plurality of magnet bodies and a cylindrical developing sleeve 240b enclosing the magnet roller 240a. Magnet roller 240 a is fixed to developer housing 210 . The developing sleeve 240b is rotatably supported by the developing housing 210. As shown in FIG. The developing sleeve 240b is rotationally driven by power from a driving mechanism (not shown). The developing roller 240 attracts the magnetic carrier C contained in the developer D in the developing housing 210 to the developing sleeve 240b by the magnetic force of the magnet roller 240a. As a result, the developing roller 240 can form the bristles of the developer D. As shown in FIG.

The layer regulating blade 250 is provided on the developing housing 210 with its tip portion spaced from the developing sleeve 240b by a predetermined distance. The layer regulation blade 250 regulates the layer thickness of the developer D. As shown in FIG. The developing roller 240 supplies the developer D to the photosensitive drum 131 by rotating the developing sleeve 240 b in a direction opposite to the rotating direction of the photosensitive drum 131 .

Receiving portion 260 receives toner T and carrier C from toner cartridge 150 . The receiving part 260 is a supply port. Receiving portion 260 communicates with a supply port of supply portion 160 . Supply unit 160 supplies toner T containing carrier C from toner cartridge 150 to development housing 210 from receiving unit 260 .

The discharging portion 270 discharges excess developer D out of the developer D contained in the development housing 210 to the outside of the development housing 210 . The discharge section 270 is provided downstream of the first conveying screw 220 in the conveying direction. More specifically, the discharge section 270 is provided downstream of the first flow port A1 in the conveying direction of the first conveying screw 220 . In other words, the discharge part 270 is provided at the downstream end of the first chamber 211 in the transport direction.

The ejection portion 270 has an ejection screw 271 and an ejection housing 272 that houses the ejection screw 271 . The discharge screw 271 is positioned downstream of the first conveying screw 220 in the conveying direction inside the discharge housing 272 and is formed coaxially with the first conveying screw 220 . The discharge screw 271 has a blade portion 271a spirally wound in a direction opposite to the blade portion 220a of the first conveying screw 220 on the rear side of the rotating shaft. The discharge screw 271 has a blade portion 271b spirally wound in the same direction as the blade portion 220a of the first conveying screw 220 on the front side of the blade portion 271a. The screw pitch of the blade portion 271 b of the discharge screw 271 is shorter than the screw pitch of the blade portion 220 a of the first conveying screw 220 .

A discharge screw 271 is provided through the developer housing 210 . The discharge housing 272 is attached to the front wall of the development housing 210 so as to cover the part of the discharge screw 271 that penetrates from the development housing 210 and is exposed to the outside. The first chamber 211 and the discharge housing 272 communicate with each other through a discharge port 211a formed in the front wall of the first chamber 211 (see FIG. 3). A discharge port (not shown) for discharging the developer D taken inside is provided at the lower front end of the discharge housing 272 . Moreover, the outside of the discharge housing 272 is covered with a housing cover 273 having an opening at a position corresponding to the discharge port.

In the above configuration, the developer D in the first chamber 211 is guided forward by the blade portion 220a of the first conveying screw 220 by rotating the first conveying screw 220 and the second conveying screw 230 . Then, when the developer D is conveyed to the vicinity of the discharge port 211a of the first chamber 211, part of the developer D resists the backward pushing force of the blade portion 271a of the discharge screw 271, and moves toward the discharge port 211a. It enters the discharge housing 272 through the hole, is guided forward by the vane portion 271b of the discharge screw 271, and is discharged out of the discharge housing 272 through a discharge port (not shown). As described above, the discharge portion 270 enables part of the developer D to be discharged to the outside of the developing device 200 .

The developing device 200 has a flow dividing section 300 that divides the air flowing into the first chamber 211 . FIG. 4 is a cross-sectional view of the developing device 200. As shown in FIG. FIG. 4 shows a cross-sectional view taken in a direction orthogonal to the axial direction of the conveying screw of the developing device 200. As shown in FIG. FIG. 5 is a perspective view of the developing device 200 showing the flow dividing portion 300. As shown in FIG. In FIG. 5, the top cover member 210b is removed to illustrate the flow diverter 300. As shown in FIG. FIG. 6 is a cross-sectional view of the developing device 200 showing the flow dividing portion 300. As shown in FIG. 6 is a cross-sectional view taken along the line AA of FIG. 4. FIG. FIG. 7 is a side view of the developing device 200 showing the flow dividing portion 300. FIG. In FIG. 7, top cover member 210b has been removed to illustrate flow diverter 300. FIG. FIG. 8 is a perspective view of the developing device 200 showing the flow dividing portion 300. As shown in FIG. In FIG. 8, the top cover member 210b has been removed to illustrate the regulating member 330, which will be described later. 5 to 8, part of the developing device 200 is omitted. 5 to 8 show a state in which the developer housing 210 does not contain the developer D. As shown in FIG.

The flow splitter 300 is provided in the partition wall 213, for example. The flow dividing section 300 is provided, for example, in a plurality of openings 310 communicating between the first chamber 211 and the second chamber 212, and in each of the plurality of openings 310 on the downstream side in the first direction. and a plurality of first guide members 320 that guide air toward each of the.

As shown in FIG. 5, the plurality of openings 310 are arranged side by side at predetermined intervals along the first direction in the partition wall 213 . Each opening 310 is, for example, a substantially rectangular opening. Although each opening 310 is a substantially rectangular opening, it is not limited to this, and may be a substantially circular, substantially elliptical, substantially polygonal, or the like opening. Each opening 310 is located above the first conveying screw 220 . The length of each opening 310 in the first direction is preferably formed to be shorter than the screw pitch P2 of the first conveying screw 220 (see FIG. 9).

As shown in FIG. 6, a first guide member 320 is provided at each of the plurality of openings 310 on the downstream side in the first direction. That is, the first guide members 320 are provided in the same number as the openings 310 . The first guide member 320 is adjacent to the downstream end of the opening 310 in the first direction.

In the first chamber 211, the first guide member 320 extends from the partition wall 213 toward the wall surface facing the partition wall 213 (in this embodiment, the left wall surface 211b of the first chamber 211). The first guide member 320 has a guide surface 320 a (rear surface) perpendicular to the partition wall 213 . For example, the guide surface 320a is arranged so as to overlap the entire opening 310 in the first direction in a side view. In this embodiment, the lower end of the guide surface 320a is located below the opening 310. As shown in FIG.

Although the guide surface 320a is a surface perpendicular to the partition wall 213, the guide surface 320a is not limited to this. For example, it may be a surface that is inclined or curved vertically from the horizontal direction. Further, the guide surface 320a is arranged so as to overlap the entire opening 310 in the first direction in a side view, but is not limited to this, and is arranged so as to overlap a part of the opening 310 in the first direction. may be

As shown in FIGS. 6 and 7, the first guide member 320 has a rectifying plate 320b extending toward the downstream side (the front side in this embodiment) in the first direction. In this embodiment, the current plate 320b extends forward from the lower end of the guide surface 320a. That is, the first guide member 320 is a flat plate-like member formed in a substantially L shape when viewed from the side. The lower surface (rectifying surface) of the rectifying plate 320b is slightly obliquely downward from the lower end of the guide surface 320a. In addition, although the rectifying plate 320b extends forward from the lower end of the guide surface 320a, it is not limited to this, and may extend forward below the opening 310, and the vertical direction of the guide surface 320a. It may extend toward the front side from the middle part of the .

As shown in FIG. 8 , the flow dividing portion 300 further includes a regulating member 330 that is provided on the upstream side of the opening 310 in the first direction in the first chamber 211 and regulates the developer D from entering the opening 310 . Prepare.

In this embodiment, the restricting member 330 is provided on the upstream side of the opening 310 located on the most upstream side in the first direction. The regulating member 330 extends from the partition wall 213 toward the wall surface facing the partition wall 213 (in this embodiment, the left wall surface 211b of the first chamber 211). In this embodiment, the regulating member 330 has a regulating surface 330 a (rear surface) perpendicular to the partition wall 213 . The restricting member 330 is, for example, a flat plate-like member having a thickness in the front-rear direction. The regulating member 330 is formed by notching the upper edge of a substantially rectangular plate-like member downward as it progresses from the base end to the tip end. For example, the regulation surface 330a overlaps the lower end portion of the opening 310 in the first direction when viewed from the side. Moreover, the regulation surface 330 a includes a portion located below the lower end of the opening 310 .

In the above configuration, the partition wall 213 is provided with the opening 310 that communicates the first chamber 211 and the second chamber 212 , so that the air flow toward the discharge port 211 a in the first chamber 211 passes through the first conveying screw 220 . Even if generated by the rotation, the air flow can be dispersed into the second chamber 212 through the opening 310 . As a result, the flow rate of the airflow reaching the discharge port 211a can be sufficiently reduced, so that the developer D can be prevented from being excessively discharged to the discharge portion 270 by the airflow. Therefore, it is possible to prevent the development roller 240 from being supplied with a desired amount of the developer D due to an excessive decrease in the amount of the developer D in the development housing 210, thereby preventing uneven stirring on the image.

Furthermore, since the partition wall 213 is provided with the first guide member 320 , the air can be guided toward the opening 310 , so that the airflow flowing in the first chamber 211 can be sufficiently transferred to the second chamber 212 through the opening 310 . can be distributed in As a result, the flow rate of the airflow reaching the discharge port 211a can be sufficiently reduced, so that the developer D can be prevented from being excessively discharged to the outside of the developing device 200 by the airflow.

Further, since the lower end of the first guide member 320 is positioned below the opening 310, the developer D enters the opening 310 positioned downstream of the first guide member 320 in the first direction. can be prevented.

Further, since the first guide member 320 has the rectifying plate 320b extending toward the downstream side in the first direction, the flow of the developer D can be regulated. Fluctuations in volume can be suppressed. In addition, it is possible to prevent the developer D from entering the opening 310 located downstream of the first guide member 320 in the first direction.

Further, since the regulating member 330 is provided on the upstream side in the first direction of the opening 310, the developer D is prevented from entering the opening 310 located on the downstream side of the regulating member 330 in the first direction. can.

Note that the flow dividing section 300 has a plurality of openings 310 and a plurality of first guide members 320, but is not limited to this. may be the first guide member 320 alone. In addition, although the flow dividing section 300 has a plurality of openings 310, the present invention is not limited to this, and for example, only one opening 310 may be provided. In addition, although the flow dividing section 300 has a plurality of first guide members 320, the present invention is not limited to this. For example, only one first guide member 320 may be provided.

The pitch between adjacent openings 310 will be described with reference to FIG. FIG. 9 is a schematic side view showing the pitch P1 between adjacent openings 310. As shown in FIG. FIG. 9 shows a comparison between the pitch P1 between adjacent openings 310 among the plurality of openings 310 and the screw pitch P2 of the first conveying screw 220 . The pitch P1 between adjacent openings 310 refers to the length from the reference position of one opening 310 to the reference position of the other opening 310 . In this embodiment, the reference position is the rear end of the opening 310 . Moreover, each of the plurality of openings 310 has the same shape, and the pitch between adjacent openings 310 has the same length.

The pitch P1 between adjacent openings 310 is a natural number multiple of the screw pitch P2 of the first conveying screw 220 . In this embodiment, the pitch P1 between adjacent openings 310 is equal to the screw pitch P2 of the first conveying screw 220 . In addition, for example, the pitch P1 between the adjacent openings 310 may be twice the screw pitch P2 of the first conveying screw 220 .

As described above, by setting the pitch P1 between the adjacent openings 310 to be a natural number multiple of the screw pitch P2 of the first conveying screw 220, the flow rate of the airflow passing through each opening 310 is made substantially uniform. be able to. Therefore, since the flow rate of the air flow toward the discharge portion 270 can be stably reduced, the developer D can be prevented from being excessively discharged to the discharge portion 270 .

A first modification of the flow splitter 300 will be described. The flow splitter 300 a is a first modification of the flow splitter 300 . FIG. 10 is a cross-sectional view of the developing device 200a showing the flow dividing portion 300a. FIG. 11 is a side view of the developing device 200a showing the flow dividing portion 300a. In FIG. 11, a portion of developer housing 210 has been removed to illustrate flow diverter 300a. 10 and 11 show a state in which the developer housing 210, which will be described later, does not contain the developer D. As shown in FIG. In the flow dividing portion 300a, the upper wall of the first chamber 211 has a vent 211c that communicates with the outside, and the first guide member 321 is positioned downstream in the first direction so as to guide air to the vent 211c. It is different from the flow dividing section 300 in that it slopes upward toward the direction of the flow dividing section 300 .

As shown in FIG. 10, the first chamber 211 has a vent 211c on the upper wall. The vent 211c is formed so as to overlap at least a part of the first guide member 321 in the vertical direction and extend in the front-rear direction. A filter 211d is provided in the vent 211c. The filter 211d is made of a material such as nonwoven fabric, for example.

As shown in FIG. 11, the first guide member 321 inclines upward toward the downstream side in the first direction. More specifically, in the first guide member 321, the guide surface 321a, which is a surface that can contact the air flowing in the first direction, is inclined upward toward the downstream side in the first direction. Just do it. It should be noted that the first guide member 321, like the first guide member 320, has a rectifying plate 321b.

As described above, by inclining the guide surface 321a upward toward the downstream side in the first direction, the air coming into contact with the guide surface 321a is guided upward, and passes through the air vent 211c to the developing device. It can be discharged to the outside of 200a. As a result, the flow rate of the airflow reaching the discharge port 211a can be sufficiently reduced, so that the developer D can be prevented from being excessively discharged to the discharge portion 270 by the airflow. In addition, since an increase in the internal pressure inside the developing housing 210 can be suppressed, scattering of the developer D can be suppressed.

A second modification of the flow splitter 300 will be described. Flow splitter 300 b is a second modification of flow splitter 300 . FIG. 12 is a perspective view of the developing device 200b showing the flow dividing portion 300b. In FIG. 12, a portion of the upper surface cover member 210b is omitted in order to illustrate the second guide member 340. As shown in FIG. FIG. 13 is a cross-sectional view of the developing device 200b showing the flow dividing portion 300b. FIG. 14 is a perspective view of the upper cover member 210b as seen from the back side. FIGS. 12 to 14 show a state in which no developer D is stored in a developer housing 210, which will be described later. In that the flow dividing portion 300b includes a second guide member 340 extending from a wall surface facing the partition wall 213 in the first chamber 211 (in this embodiment, the left wall surface 211b of the first chamber 211) toward the partition wall 213. , is different from the flow diverter 300 .

As shown in FIGS. 12 to 14, the second guide member 340 extends from the wall surface facing the partition wall 213 (in this embodiment, the left wall surface 211b of the first chamber 211) to the partition wall 213 in the first chamber 211. stretch towards. In this embodiment, the second guide member 340 is a flat plate-shaped member having a guide surface perpendicular to the partition wall 213 and having a thickness in the front-rear direction, like the first guide member 320 . The guide surface of the second guide member 340 is arranged so as to overlap the entire opening 310 in the first direction in a side view. Also, the lower end of the second guide member 340 is located below the opening 310 . The plurality of second guide members 340 are arranged side by side in the first direction at predetermined intervals on the left wall surface 211b of the first chamber 211 .

As shown in FIG. 13, the plurality of first guide members 320 and the plurality of second guide members 340 are alternately arranged along the first direction. That is, each second guide member 340 is arranged to be positioned between the first guide members 320 arranged in the first direction. The tip side of the first guide member 320 and the tip side of the second guide member 340 are arranged so as to overlap in the first direction. The second guide member 340 is arranged so as not to overlap the opening 310 in a direction orthogonal to the first direction. Specifically, the second guide member 340 is located upstream of the upstream end of the opening 310 in the first direction.

As described above, by arranging the plurality of first guide members 320 and the plurality of second guide members 340 alternately along the first direction, the air flowing in the first chamber 211 It flows while bypassing the guide member 320 and the second guide member 340 . Therefore, since the flow rate of the airflow reaching the discharge port 211a can be sufficiently reduced, it is possible to prevent the developer D from being excessively discharged to the discharge portion 270 by the airflow.

Although the second guide member 340 has a guide surface perpendicular to the partition wall 213, the second guide member 340 is not limited to this. For example, it may have a surface inclined vertically from the horizontal direction. In addition, the second guide member 340 is preferably arranged so as to overlap the entire opening 310 in the first direction in a side view, but is not limited to this, and overlaps a part of the opening 310 in the first direction. may be arranged as Further, the second guide member 340 may have a current plate extending downstream in the first direction, like the first guide member 320 .

In the above configuration, the developing device 200 includes a developing housing 210 containing the developer D, a first conveying screw 220 and a second conveying screw 230 for circulating and conveying the developer D within the developing housing 210, and a first A first chamber 211 that guides the developer D in the first direction by rotation of the conveying screw 220, and a second chamber 212 that guides the developer D in the direction opposite to the first direction by the rotation of the second conveying screw 230, A partition wall 213 that separates the first chamber 211 and the second chamber 212 has an opening 310 that communicates the first chamber 211 and the second chamber 212 .

Accordingly, even if an airflow is generated in the first chamber 211 by the rotation of the first conveying screw 220 , the airflow can be dispersed to the second chamber 212 through the opening 310 . Therefore, the airflow can prevent the developer D from scattering and leaking out of the developing housing 210 through the gap between the developing sleeve 240b and the developing housing 210, for example.

The developing device 200 further includes a discharging portion 270 provided at the downstream end of the first chamber 211 in the first direction and discharging part of the developer D to the outside of the developing housing 210 . As a result, even if an airflow directed toward the discharge portion 270 is generated due to the rotation of the first conveying screw 220 , the airflow can be dispersed in the second chamber 212 through the opening 310 . Therefore, since the flow rate of the airflow reaching the discharge portion 270 can be sufficiently reduced, it is possible to prevent the developer D from being excessively discharged to the discharge portion 270 by the airflow. Therefore, it is possible to prevent the amount of the developer D in the development housing 210 from decreasing and the development roller 240 to be unable to be supplied with the desired amount of the developer D, thereby preventing uneven agitation on the image.

Further, the partition wall 213 further includes a first guide member 320 provided downstream of the opening 310 in the first direction in the first chamber 211 and guiding air toward the opening 310 . extends from the partition wall 213 toward the wall surface (left wall surface 211b) facing the partition wall 213. As shown in FIG. As a result, air can be guided toward the opening 310 , so that the airflow flowing in the first chamber 211 can be sufficiently dispersed in the second chamber 212 through the opening 310 . Therefore, the air flow generated by the rotation of the first conveying screw 220 can prevent the developer D from scattering and leaking out of the developing housing 210 or from being excessively discharged to the discharge portion 270 .

The first guide member 320 has a current plate 320b extending downstream in the first direction. As a result, the flow of the developer D can be regulated, so that scattering of the developer D can be suppressed and variations in the amount of the developer D discharged from the discharge section 270 can be suppressed. In addition, it is possible to prevent the developer D from entering the opening 310 located downstream of the first guide member 320 in the first direction.

The partition wall 213 further includes a regulating member 330 provided on the upstream side of the opening 310 in the first direction in the first chamber 211 and regulating developer D from entering the opening 310 . Thereby, the developer D can be prevented from entering the opening 310 located downstream of the regulating member 330 in the first direction.

The upper wall of the first chamber 211 has a vent 211c that communicates with the outside, and the first guide member 320 extends upward toward the downstream side in the first direction so as to guide air to the vent 211c. tilt to As a result, the air contacting the first guide member 320 can be discharged to the outside of the developing device through the vent 211c. Therefore, since the flow rate of the airflow reaching the discharge portion 270 can be sufficiently reduced, it is possible to prevent the developer D from being excessively discharged to the discharge portion 270 by the airflow. In addition, since an increase in the internal pressure inside the developing housing 210 can be suppressed, scattering of the developer D can be suppressed.

The partition wall 213 further includes a plurality of openings 310, the plurality of openings 310 are provided side by side along the first direction, and the pitch P1 between adjacent openings 310 among the plurality of openings 310 is It is a natural number multiple of the screw pitch P2 of the first conveying screw 220 . Thereby, the flow rate of the airflow passing through each opening 310 can be made substantially uniform. Therefore, the air flow generated by the rotation of the first conveying screw 220 can prevent the developer D from scattering and leaking out of the developing housing 210 or from being excessively discharged to the discharge portion 270 .

The partition wall 213 has a plurality of openings 310 and a plurality of first guide members 320 , and the lower ends of the first guide members 320 are located below the openings 310 . Thereby, the developer D can be prevented from entering the opening 310 located downstream of the first guide member 320 in the first direction.

A plurality of first guide members 320 and a plurality of second guide members 340 extending from the wall surface (left wall surface 211b) of the first chamber 211 toward the partition wall 213 are provided. The second guide members 340 are alternately arranged along the first direction. Thereby, the air flowing in the first chamber 211 flows while bypassing the first guide member 320 and the second guide member 340 . Therefore, the air flow generated by the rotation of the first conveying screw 220 can prevent the developer D from scattering and leaking out of the developing housing 210 or from being excessively discharged to the discharge portion 270 .

The present invention is not limited to the above embodiments, and various modifications are possible. For example, it can be replaced with a configuration that is substantially the same as the configuration shown in the above embodiment, a configuration that produces the same effects, or a configuration that can achieve the same purpose.

200 developing device, 200a developing device, 200b developing device, 210 developing housing, 211 first chamber, 211c ventilation port, 212 second chamber, 213 partition wall, 220 first conveying screw, 230 second conveying screw, 310 opening, 320 first guide member 321 first guide member 320b current plate 330 regulating member 340 second guide member P1 pitch between adjacent openings P2 screw pitch of first conveying screw

Claims (9)

a developer housing containing developer;
two transport screws for circulating and transporting the developer within the developer housing;
a first chamber for guiding the developer in a first direction by rotation of one of the two conveying screws;
a second chamber for guiding the developer in a direction opposite to the first direction by the rotation of the other of the two conveying screws;
A developing device, wherein a partition wall that partitions the first chamber and the second chamber has an opening that communicates the first chamber and the second chamber. The partition wall further comprises a first guide member provided downstream of the opening in the first direction in the first chamber and guiding air toward the opening,
2. The developing device according to claim 1, wherein said first guide member extends from said partition wall toward a wall surface facing said partition wall. 3. The developing device according to claim 2, wherein the first guide member has a current plate extending downstream in the first direction. 3. The partition wall further comprises a regulating member provided on the upstream side of the opening in the first direction in the first chamber, the regulating member regulating entry of the developer into the opening. Item 4. The developing device according to item 3. The upper wall of the first chamber has a vent communicating with the outside,
5. The development according to any one of claims 2 to 4, wherein the first guide member is inclined upward toward the downstream side in the first direction so as to guide air to the air vent. Device. further comprising a plurality of openings, each said opening;
The plurality of openings are provided side by side along the first direction,
6. The developing device according to claim 2, wherein a pitch between adjacent openings among said plurality of openings is a natural number multiple of a screw pitch of said conveying screw. a plurality of openings, each said opening;
a plurality of first guide members each being the first guide member;
7. The developing device according to claim 2, wherein the lower end of the first guide member is located below the opening. a plurality of first guide members each being the first guide member;
a plurality of second guide members extending from the wall surface of the first chamber toward the partition wall;
8. The developing device according to claim 2, wherein the plurality of first guide members and the plurality of second guide members are alternately arranged along the first direction. 9. The apparatus according to any one of claims 1 to 8, further comprising a discharge section provided at a downstream end of the first chamber in the first direction and discharging a part of the developer to the outside of the development housing. 3. The developing device according to the above paragraph.

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