JP5877079B2 - Developing device and image forming apparatus - Google Patents

Description

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

  2. Description of the Related Art Conventionally, a developing device that uses a two-component developer composed of toner and a carrier and an image forming device that forms an image using the developing device are widely known. At the time of image formation, the toner is fixed on the recording paper and consumed, but the carrier is hardly consumed and remains in the developing device. Accordingly, when the developing device is replenished with only toner and the carrier is repeatedly used, the carrier is worn and deteriorated, and as a result, the image quality of the formed image is deteriorated.

  As apparatuses for solving such problems, Patent Documents 1 and 2 describe a developing apparatus capable of replacing a deteriorated carrier with a new carrier. The developing devices described in Patent Documents 1 and 2 are connected to a replenishing device that stores a two-component developer composed of toner and a new carrier, and the toner and deterioration are made while replenishing the two-component developer little by little from the replenishing device. The two-component developer consisting of the prepared carrier is discharged little by little. The developing devices described in Patent Documents 1 and 2 are each provided with a mechanism for preventing the amount of the two-component developer to be discharged from increasing undesirably. By this mechanism, the developing devices described in Patent Documents 1 and 2 prevent the amount of the two-component developer discharged from increasing compared to the amount of the two-component developer to be replenished.

  Specifically, the developing device described in Patent Document 1 includes a developing tank for storing a two-component developer, a rotating shaft member and a spiral blade for conveying the two-component developer in the developing tank to a developing roller. And an auger screw formed in the developing tank for discharging the deteriorated carrier, and the auger screw is in a wide range including a portion facing the discharge port in the axial direction of the rotary shaft member. A portion where the spiral blade is not provided is formed. As a result, the developing device described in Patent Document 1 prevents the two-component developer from being scattered by the spiral blade near the discharge port, and the discharge amount of the two-component developer from being undesirably increased.

  In addition, a developing device described in Patent Document 2 includes an auger including a developing tank for storing a two-component developer, and a rotary shaft member and a spiral blade for conveying the two-component developer in the developing tank to the developing roller. A discharge port for discharging the deteriorated carrier is formed in the downstream portion of the developing tank in the transport direction by the auger screw. As a result, the developing device described in Patent Document 2 can discharge the deteriorated carrier at the downstream side in the transport direction of the developing tank, where the two-component developer transported in the developing tank tends to stay. The two-component developer is scattered by the spiral blade near the discharge port, and the discharge amount of the two-component developer is prevented from increasing undesirably.

JP 2009-58649 A JP 2009-63991 A

  When the toner or carrier in the two-component developer deteriorates, the fluidity of the two-component developer may decrease. When the fluidity of the two-component developer is lowered, a phenomenon occurs in which the surface of the two-component developer conveyed by the auger screw undulates.

  Although the developing devices described in Patent Documents 1 and 2 suppress an undesired increase in the discharge amount due to the scattering of the two-component developer, they can cope with the phenomenon that the surface of the two-component developer undulates. Absent. That is, in the developing devices described in Patent Documents 1 and 2, when the fluidity of the two-component developer is reduced and the surface of the two-component developer being conveyed is undulated, a large amount of two-component is produced in a portion where the wave height is high. As the developer is discharged and a small amount of the two-component developer is discharged at a portion where the wave height is low, the amount of the two-component developer discharged varies. If the amount of the two-component developer to be discharged varies, the amount of the two-component developer to be supplied cannot be balanced, and a good image cannot be formed.

  SUMMARY An advantage of some aspects of the invention is that it provides a developing device and an image forming apparatus that can suppress variations in the amount of developer discharged.

The present invention provides a developing device that develops an electrostatic latent image on an image carrier by supplying the developer to the image carrier.
A developer tank for storing developer, when the developer surface exceeds a predetermined height in the vertical direction with the bottom of the developer tank at the bottom and the ceiling at the top. A developing tank in which a discharge port for discharging out of the developing tank is formed;
A transport member that transports the developer in the developer tank in a transport direction that intersects the vertical direction;
A guide member that forms a hollow body together with a part of the developing tank surrounding the discharge port,
The hollow body is a hollow body in which the discharge port is located in a side wall portion and a lower end portion in the vertical direction is opened.
The guide member is
An upstream plate extending perpendicularly to the transport direction and provided upstream of the discharge port in the transport direction;
A downstream plate extending perpendicularly to the transport direction and provided downstream of the discharge port in the transport direction;
A connection plate extending in the transport direction and connecting the upstream plate and the downstream plate;
The upstream plate is provided such that a lower end portion in the vertical direction is on the upper side in the vertical direction with respect to a lower end portion in the vertical direction of the discharge port.
The guide member guides a part of the developer transported in the transport direction by the transport member to the upper side in the vertical direction through the opening and discharges the developer from the discharge port. It is.

According to the present invention, the developing tank includes a partition, and by the partition, the first transport path along the longitudinal direction of the partition, the second transport path facing the first transport path across the partition, and the length of the partition A first communication path communicating the first conveyance path and the second conveyance path on one end side in the direction, and a second communicating the first conveyance path and the second conveyance path on the other longitudinal end side of the partition wall. Divided into communication passages,
The conveying member is
A rotating shaft member, and a spiral blade that surrounds the rotating shaft member and rotates as the rotating shaft member rotates about the axis, from one of the first communication path and the second communication path A spiral blade provided so that the direction toward the other is the transport direction,
Provided in one of the first transport path or the second transport path;
The discharge port is formed so as to face a portion connected to the other of the first communication path or the second communication path of the one of the first conveyance path or the second conveyance path,
The guide member is provided on the one of the first transport path and the second transport path,
The downstream plate is provided such that a lower end portion in the vertical direction is located on the lower side in the vertical direction with respect to a lower end portion in the vertical direction of the discharge port.

  In the present invention, the spiral blade is a large-diameter spiral blade provided at a position not facing the discharge port, and a small-diameter spiral blade provided at a position facing the discharge port and having an outer diameter smaller than that of the large-diameter spiral blade. It is characterized by including.

  In the invention, it is preferable that the spiral blade has a multiple spiral structure on the upstream side in the transport direction from the discharge port.

The present invention also provides an electrophotographic image forming apparatus,
An image forming apparatus comprising the developing device.

  According to the present invention, a part of the developer transported in the transport direction passes through the lower end of the hollow body formed by the guide member and the developing tank, passes through the inside of the hollow body, and moves upward in the vertical direction. To do. At this time, the developer surface of the developer moving upward in the vertical direction is flattened by the pressing force generated by the weight of the developer or the weight of the developer outside the hollow body. Therefore, even when the developer fluidity is reduced and the developer surface of the developer conveyed in the conveyance direction is wavy, the developer surface of the developer moving up and down the vertical direction In this state, a part of the developer that moves up and down is discharged from the discharge port. Thereby, even when the developer surface of the developer conveyed in the conveyance direction is wavy, variation in the amount of the developer discharged from the discharge port can be suppressed.

Also, the upstream plate of the guide member, since extends perpendicular to the conveying direction, it is easy to stay the developer transported by the transport member, whereby when the developer surface of the developer conveyed is wavy The height difference in the vertical direction of the developer surface can be suppressed. Further, since the downstream plate of the guide member extends perpendicularly to the transport direction, when the developer moves in the direction opposite to the transport direction, the developer is blocked and the developer is undesirably discharged from the discharge port. Can be prevented. Further, since the connecting plate of the guide member extends in the transport direction, the flow of the developer transported in the transport direction is not hindered.

Also, the vertical direction lower end of the upstream plate, so positioned vertically above the vertical lower portion of the discharge port, the developer of the developer entering the inside of the hollow body constituted by the guide member and the developing tank The height of the surface is reduced, thereby preventing the developer from being compressed and being surely discharged from the discharge port.

  Further, according to the present invention, the discharge port is formed facing a portion that is continuous with the communication path on the downstream side in the transport direction of the transport path in which the transport member is provided. It can be discharged from the outlet. Furthermore, since the lower end in the vertical direction of the downstream plate is located on the lower side in the vertical direction than the lower end in the vertical direction of the discharge port, the developer staying on the downstream side in the transport direction with respect to the downstream plate snows into the discharge port. Can be suppressed.

  Moreover, according to this invention, a small diameter spiral blade is provided in the position which faces a discharge port in a conveyance member, and a large diameter spiral blade is provided in the position which does not face a discharge port. The small-diameter spiral blade and the large-diameter spiral blade displace the developer in the vertical direction due to friction during rotation, which causes the developer surface to be waved. The distance from the surface is relatively long, and it is difficult for the developer surface to be relatively undulated. Therefore, the small-diameter spiral blade can displace the developer in the vertical direction while suppressing the undulation of the developer surface, so that the inside of the hollow body constituted by the guide member and the developing tank is directed upward in the vertical direction. When the moving developer is a lump, the lump can be crushed and reliably discharged from the discharge port.

  Further, according to the present invention, since the spiral blades of the multiple spiral structure are provided upstream in the transport direction from the discharge port, when the developer surface is wavy, the apex interval (wave pitch) of adjacent waves is set. As a result, the developer surface can be easily flattened by the guide member.

  Further, according to the present invention, since the developing device can suppress variation in the amount of developer discharged, it is possible to balance the amount of developer supplied to the developing device and the amount of developer discharged. It is possible to form a high-quality image.

1 is a schematic diagram illustrating a configuration of an image forming apparatus 100. FIG. 3 is a schematic diagram showing a configuration of a developer cartridge 300. FIG. FIG. 3 is a cross-sectional view of a developer cartridge 300 taken along line AA shown in FIG. 2 is a schematic diagram illustrating a configuration of a developing device 200. FIG. FIG. 5 is a cross-sectional view of the developing device 200 with the line BB shown in FIG. FIG. 6 is a cross-sectional view of the developing device 200 with the line CC shown in FIG. 5 as a cut surface line. It is sectional drawing of the developing device 200 which makes the line DD shown in FIG. 6 a cut surface line. FIG. 8 is an external view of the developing device 200 when viewed in a direction perpendicular to the cross section shown in FIG. 7. 5 is a perspective view of a guide member 209. FIG. It is a figure which expands and shows a part of FIG. It is a figure for demonstrating the effect of the upstream board 209a. It is a figure for demonstrating the effect of the downstream board 209b.

  First, the image forming apparatus 100 including the developing device 200 according to the embodiment of the present invention will be described. FIG. 1 is a schematic diagram illustrating a configuration of the image forming apparatus 100. The image forming apparatus 100 is a multifunction device having both a copying function, a printer function, and a facsimile function, and forms a full-color or monochrome image on a recording medium according to transmitted image information. The image forming apparatus 100 has three types of printing modes, ie, a copier mode (copy mode), a printer mode, and a facsimile mode, and an operation input from an operation unit (not shown), a personal computer, a portable terminal device, and an information recording medium A print mode is selected by a control unit (not shown) in response to reception of a print job from an external device using the memory device.

  The image forming apparatus 100 includes a toner image forming unit 20, a transfer unit 30, a fixing unit 40, a recording medium supply unit 50, a discharge unit 60, and a control unit unit (not shown). The toner image forming unit 20 includes photosensitive drums 21b, 21c, 21m, and 21y, charging units 22b, 22c, 22m, and 22y, an exposure unit 23, developing devices 200b, 200c, 200m, and 200y, a cleaning unit 25b, 25c, 25m, 25y, developer cartridges 300b, 300c, 300m, 300y, and developer supply pipes 250b, 250c, 250m, 250y. The transfer unit 30 includes an intermediate transfer belt 31, a driving roller 32, a driven roller 33, intermediate transfer rollers 34 b, 34 c, 34 m and 34 y, a transfer belt cleaning unit 35, and a transfer roller 36.

  The photosensitive drum 21, the charging unit 22, the developing device 200, the cleaning unit 25, the developer cartridge 300, the developer supply pipe 250, and the intermediate transfer roller 34 are black (b) and cyan (c) included in the color image information. In order to correspond to the image information of each color of magenta (m) and yellow (y), four each are provided. In this specification, when distinguishing each member provided by four according to each color, an alphabet representing each color is added to the end of a number representing each member as a reference symbol, and when each member is collectively referred to Only numerals representing each member are used as reference numerals.

  The photosensitive drum 21 is supported by a drive unit (not shown) so as to be rotatable about an axis, and includes a conductive substrate (not shown) and a photoconductive layer formed on the surface of the conductive substrate. The conductive substrate can take various shapes, and examples thereof include a cylindrical shape, a columnar shape, and a thin film sheet shape. The photoconductive layer is formed of a material that exhibits conductivity when irradiated with light. As the photosensitive drum 21, for example, a cylindrical member (conductive base) formed of aluminum, and amorphous silicon (a-Si), selenium (Se), and the like formed on the outer peripheral surface of the cylindrical member, Alternatively, a film including a thin film (photoconductive layer) made of an organic optical semiconductor (OPC) can be used.

  The charging unit 22, the developing device 200, and the cleaning unit 25 are arranged in this order around the rotation direction of the photosensitive drum 21, and the charging unit 22 is arranged below the developing device 200 and the cleaning unit 25 in the vertical direction. The

  The charging unit 22 is a device that charges the surface of the photosensitive drum 21 to a predetermined polarity and potential. The charging unit 22 is installed along the longitudinal direction of the photosensitive drum 21 at a position facing the photosensitive drum 21. In the case of the contact charging method, the charging unit 22 is installed in contact with the surface of the photosensitive drum 21. In the case of the non-contact charging method, the charging unit 22 is installed so as to be separated from the surface of the photosensitive drum 21.

  The charging unit 22 is installed around the photosensitive drum 21 together with the developing device 200, the cleaning unit 25, and the like. The charging unit 22 is preferably installed at a position closer to the photosensitive drum 21 than the developing device 200, the cleaning unit 25, and the like. As a result, it is possible to reliably prevent the charging failure of the photosensitive drum 21.

  As the charging unit 22, a brush-type charging device, a roller-type charging device, a corona discharge device, an ion generation device, or the like can be used. The brush type charging device and the roller type charging device are contact charging type charging devices. As the brush type charging device, there are a type using a charging brush and a type using a magnetic brush. The corona discharge device and the ion generator are non-contact charging devices. Corona discharge devices include those using wire-like discharge electrodes, those using sawtooth discharge electrodes, and those using needle-like discharge electrodes.

  The exposure unit 23 is arranged such that light emitted from the exposure unit 23 passes between the charging unit 22 and the developing device 200 and is irradiated on the surface of the photosensitive drum 21. The exposure unit 23 irradiates the charged surface of the photosensitive drums 21b, 21c, 21m, and 21y with laser beams corresponding to the image information of the respective colors, so that each of the photosensitive drums 21b, 21c, 21m, and 21y is exposed. An electrostatic latent image corresponding to the image information of each color is formed on the surface. As the exposure unit 23, for example, a laser scanning unit (LSU) including a laser irradiation unit and a plurality of reflection mirrors can be used. As the exposure unit 23, an LED (Light Emitting Diode) array, a unit in which a liquid crystal shutter and a light source are appropriately combined, or the like may be used.

  The developing device 200 is a device that forms a toner image on the photosensitive drum 21 by developing the electrostatic latent image formed on the photosensitive drum 21 with toner. A developer supply pipe 250 that is a cylindrical member is connected to the upper part of the developing device 200 in the vertical direction. Details of the developing device 200 will be described later.

  The developer cartridge 300 is disposed vertically above the developing device 200 and stores a two-component developer composed of unused toner and a carrier. A developer supply pipe 250 is connected to the lower part of the developer cartridge 300 in the vertical direction. The developer cartridge 300 supplies the two-component developer to the developing device 200 via the developer supply pipe 250. Details of the developer cartridge 300 will be described later.

  The cleaning unit 25 is a member that removes the toner remaining on the surface of the photosensitive drum 21 after the toner image is transferred from the photosensitive drum 21 to the intermediate transfer belt 31 and cleans the surface of the photosensitive drum 21. . As the cleaning unit 25, for example, a plate-like member for scraping off toner and a container-like member for collecting the scraped toner are used.

  According to the toner image forming unit 20, the surface of the photosensitive drum 21 that is uniformly charged by the charging unit 22 is irradiated with laser light corresponding to image information from the exposure unit 23 to form an electrostatic latent image. . A toner image is formed by supplying toner from the developing device 200 to the electrostatic latent image on the photosensitive drum 21. This toner image is transferred to an intermediate transfer belt 31 described later. After the toner image is transferred to the intermediate transfer belt 31, the toner remaining on the surface of the photosensitive drum 21 is removed by the cleaning unit 25.

  The intermediate transfer belt 31 is an endless belt-like member that is disposed above the photosensitive drum 21 in the vertical direction. The intermediate transfer belt 31 is stretched by the driving roller 32 and the driven roller 33 to form a loop-shaped path, and moves in the direction of the arrow A4.

  The drive roller 32 is provided so as to be rotatable around its axis by a drive unit (not shown). The drive roller 32 moves the intermediate transfer belt 31 in the direction of the arrow A4 by its rotation. The driven roller 33 is provided so as to be able to rotate following the rotation of the driving roller 32, and generates a certain tension on the intermediate transfer belt 31 so that the intermediate transfer belt 31 does not loosen.

  The intermediate transfer roller 34 is provided in pressure contact with the photosensitive drum 21 via the intermediate transfer belt 31 and rotatable about its axis by a drive unit (not shown). As the intermediate transfer roller 34, for example, a metal (for example, stainless steel) roller having a diameter of 8 mm to 10 mm on which a conductive elastic member is formed can be used. The intermediate transfer roller 34 is connected to a power source (not shown) for applying a transfer bias, and has a function of transferring the toner image on the surface of the photosensitive drum 21 to the intermediate transfer belt 31.

  The transfer roller 36 is provided in pressure contact with the drive roller 32 via the intermediate transfer belt 31 and is rotatable about an axis by a drive unit (not shown). At the pressure contact portion (transfer nip portion) between the transfer roller 36 and the drive roller 32, the toner image carried and conveyed by the intermediate transfer belt 31 is transferred to a recording medium fed from a recording medium supply unit 50 described later. The

  The transfer belt cleaning unit 35 is provided so as to face the driven roller 33 through the intermediate transfer belt 31 and to be in contact with the toner image carrying surface of the intermediate transfer belt 31. The transfer belt cleaning unit 35 is provided for removing and collecting the toner on the surface of the intermediate transfer belt 31 after the toner image is transferred to the recording medium. If toner remains on the intermediate transfer belt 31 after the toner image is transferred to the recording medium, the residual toner may adhere to the transfer roller 36 due to the movement of the intermediate transfer belt 31. When toner adheres to the transfer roller 36, the toner contaminates the back surface of the recording medium to be transferred next.

  According to the transfer unit 30, when the intermediate transfer belt 31 moves while being in contact with the photosensitive drum 21, a transfer bias having a polarity opposite to the charging polarity of the toner on the surface of the photosensitive drum 21 is applied to the intermediate transfer roller 34. The toner image formed on the surface of the photosensitive drum 21 is transferred onto the intermediate transfer belt 31. The toner images of the respective colors respectively formed on the photosensitive drum 21y, the photosensitive drum 21m, the photosensitive drum 21c, and the photosensitive drum 21b are sequentially transferred onto the intermediate transfer belt 31 in this order, thereby transferring full color. A toner image is formed. The toner image transferred to the intermediate transfer belt 31 is conveyed to the transfer nip portion by the movement of the intermediate transfer belt 31, and transferred to the recording medium at the transfer nip portion. The recording medium on which the toner image is transferred is conveyed to a fixing unit 40 described later.

  The recording medium supply unit 50 includes a paper feed box 51, pickup rollers 52 a and 52 b, transport rollers 53 a and 53 b, registration rollers 54, and a paper feed tray 55. The paper feed box 51 is a container-like member that is provided in the lower part of the image forming apparatus 100 in the vertical direction and stores a recording medium inside the image forming apparatus 100. The paper feed tray 55 is a tray-like member that is provided on the outer wall surface of the image forming apparatus 100 and stores a recording medium outside the image forming apparatus 100. Examples of the recording medium include plain paper, color copy paper, overhead projector sheet, and postcard.

  The pickup roller 52a is a member that takes out recording media stored in the paper feed box 51 one by one and feeds it to the paper transport path A1. The transport rollers 53a are a pair of roller-like members provided so as to be in pressure contact with each other, and transport the recording medium toward the registration rollers 54 in the paper transport path A1. The pickup roller 52b is a member that takes out the recording medium stored in the paper feed tray 55 one by one and feeds it to the paper transport path A2. The transport rollers 53b are a pair of roller-like members provided so as to be in pressure contact with each other, and transport the recording medium toward the registration rollers 54 in the paper transport path A2.

  The registration rollers 54 are a pair of roller-like members provided so as to come into pressure contact with each other, and the toner image carried on the intermediate transfer belt 31 is conveyed to the transfer nip portion of the recording medium fed from the conveyance rollers 53a and 53b. In synchronization with this, the sheet is fed to the transfer nip portion.

  According to the recording medium supply unit 50, the recording medium is transferred from the paper feed box 51 or the paper feed tray 55 to the transfer nip portion in synchronization with the toner image carried on the intermediate transfer belt 31 being conveyed to the transfer nip portion. The toner image is transferred to the recording medium.

  The fixing unit 40 includes a heating roller 41 and a pressure roller 42. The heating roller 41 is controlled to have a predetermined fixing temperature. The pressure roller 42 is a roller that is in pressure contact with the heating roller 41. The heating roller 41 nips the recording medium together with the pressure roller 42 while heating, thereby melting and fixing the toner constituting the toner image on the recording medium. The recording medium on which the toner image is fixed is conveyed to a discharge unit 60 described later.

  The discharge unit 60 includes a conveyance roller 61, a discharge roller 62, and a discharge tray 63. The conveyance roller 61 is a pair of roller-like members provided so as to be in pressure contact with each other in the vertical direction above the fixing unit 40. The conveyance roller 61 conveys the recording medium on which the image is fixed toward the discharge roller 62.

  The discharge roller 62 is a pair of roller-like members provided so as to be in pressure contact with each other. In the case of single-sided printing, the discharge roller 62 discharges the recording medium on which single-sided printing has been completed to the discharge tray 63. In the case of duplex printing, the discharge roller 62 conveys the recording medium on which single-sided printing has been completed to the registration roller 54 via the paper conveyance path A <b> 3, and discharges the recording medium on which duplex printing has been completed to the discharge tray 63. The discharge tray 63 is provided on the upper surface in the vertical direction of the image forming apparatus 100 and stores a recording medium on which an image is fixed.

  Image forming apparatus 100 includes a control unit (not shown). The control unit unit is provided, for example, at an upper part in the vertical direction in the internal space of the image forming apparatus 100 and includes a storage unit, a calculation unit, and a control unit. The storage unit stores various setting values via an operation panel (not shown) arranged on the upper surface in the vertical direction of the image forming apparatus 100, detection results from sensors (not shown) arranged at various locations inside the image forming apparatus 100, external devices, and the like. The image information from is input. A program for executing various processes is written in the storage unit. Examples of the various processes include a recording medium determination process, an adhesion amount control process, and a fixing condition control process.

  As the storage unit, those commonly used in this field can be used, and examples thereof include a read only memory (ROM), a random access memory (RAM), and a hard disk drive (HDD). As the external device, an electric or electronic device that can form or acquire image information and can be electrically connected to the image forming apparatus 100 can be used. For example, a computer, a digital camera, a television receiver, a video recorder DVD (Digital Versatile Disc) recorder, HDDVD (High-Definition Digital Versatile Disc) recorder, Blu-ray disc recorder, facsimile apparatus, portable terminal apparatus, and the like.

  The calculation unit retrieves various data (image formation command, detection result, image information, etc.) written in the storage unit and various processing programs, and performs various determinations. The control unit performs operation control by sending a control signal to each device provided in the image forming apparatus 100 according to the determination result of the calculation unit.

  The control unit and the calculation unit include a processing circuit realized by a microcomputer, a microprocessor, or the like provided with a central processing unit (CPU). The control unit unit includes a main power source together with the processing circuit, and the power source supplies power not only to the control unit unit but also to each device provided in the image forming apparatus 100.

  FIG. 2 is a schematic diagram illustrating the configuration of the developer cartridge 300. FIG. 3 is a cross-sectional view of the developer cartridge 300 taken along line AA shown in FIG. The developer cartridge 300 is a device that supplies a two-component developer to the developing device 200 via the developer supply pipe 250. The developer cartridge 300 includes a developer storage container 301, a developer scooping member 302, a developer discharge member 303, and a developer discharge container 304.

  The developer storage container 301 is a container-like member having a substantially semi-cylindrical internal space. In the internal space, the developer pumping member 302 is rotatably supported, and two-component development made up of unused toner and carrier. Contains the agent. In this embodiment, the mixing ratio (toner concentration) of the toner with respect to the carrier in the two-component developer in the developer container 301 is set higher than that in the two-component developer in the developing device 200. Yes.

  The developer discharge container 304 is a container-like member having a substantially semi-cylindrical internal space provided along the longitudinal direction of the developer storage container 301, and the developer discharge member 303 is rotatably supported in the internal space. To do. The internal space of the developer storage container 301 and the internal space of the developer discharge container 304 communicate with each other via a communication port 305 formed along the longitudinal direction of the developer storage container 301.

  The developer discharge container 304 has a discharge port 306 formed in the lower part in the vertical direction. A developer supply pipe 250 is connected to the developer discharge container 304 at a discharge port 306.

  The developer scooping member 302 includes a rotating shaft 302a, a base 302b, and a sliding portion 302c. The rotation shaft 302 a is a columnar member that extends along the longitudinal direction of the developer container 301. The base 302b is a plate-like member that extends along the longitudinal direction of the developer container 301, and is attached to the rotation shaft 302a at the center in the width direction and the thickness direction. The sliding portion 302c is a flexible member attached to both ends in the width direction of the base body 302b, and is formed of, for example, polyethylene terephthalate (PET). In the developer scooping member 302, the base 302b rotates as the rotary shaft 302a rotates about its axis, and as a result, the sliding portions 302c provided at both ends in the width direction of the base 302b become the developer container 301. The two-component developer in the developer container 301 is pumped up to the developer discharge container 304 by rubbing the inner wall surface.

  The developer discharge member 303 is a member that conveys the two-component developer in the developer discharge container 304 toward the discharge port 306 while stirring. The developer discharge member 303 is an auger screw-like member including a discharge rotation shaft 303a and discharge blades 303b provided around the discharge rotation shaft 303a.

  According to the developer cartridge 300, unused two-component developer in the developer container 301 is pumped up to the developer discharge container 304 by the developer pumping member 302. Then, the two-component developer pumped up to the developer discharge container 304 is conveyed to the discharge port 306 by the developer discharge member 303. The two-component developer conveyed to the discharge port 306 is discharged from the discharge port 306 to the outside of the developer discharge container 304 and is supplied to the developing device 200 via the developer supply pipe 250.

  FIG. 4 is a schematic diagram illustrating the configuration of the developing device 200. FIG. 5 is a cross-sectional view of the developing device 200 with the line BB shown in FIG. FIG. 6 is a cross-sectional view of the developing device 200 in which the line CC shown in FIG. FIG. 7 is a cross-sectional view of the developing device 200 with the line DD shown in FIG. FIG. 8 is an external view of the developing device 200 when viewed in a direction perpendicular to the cross section shown in FIG.

  The developing device 200 is a device that develops an electrostatic latent image formed on the surface of the photosensitive drum 21 by supplying toner to the surface of the photosensitive drum 21. The developing device 200 includes a developing tank 201, a first conveying member 202, a second conveying member 203, a developing roller 204, a developing tank cover 205, a doctor blade 206, a partition wall 207, and a toner concentration detection sensor 208. , A guide member 209, a waste developer transport container 210, a waste developer transport member 211, and a waste developer collection container 212.

  The developing tank 201 is a member in which an internal space is formed by the side wall portions 201a and 201b and the bottom wall portion 201c, and a two-component developer composed of toner and a carrier is stored in the internal space. The side wall parts 201a and 201b and the bottom wall part 201c may be integrally formed, or may be separate members. The developing tank 201 is made of a resin material such as polyethylene, polypropylene, high impact polystyrene, and ABS resin (acrylonitrile-butadiene-styrene copolymer synthetic resin).

  The developing tank 201 is provided with a developing tank cover 205 above the vertical direction. In the internal space, the first conveying member 202, the second conveying member 203, the developing roller 204, the doctor blade 206, the partition wall 207, and the guide member 209 are provided. Is provided. In addition, a toner concentration detection sensor 208 is provided at a lower portion (bottom portion) in the vertical direction of the developing tank 201.

  The developing tank 201 is provided with an opening between the photosensitive drum 21 and the developing roller 204. The developing roller 204 includes a magnet roller, carries the two-component developer in the developing tank 201 on the surface, and supplies toner contained in the carried two-component developer to the photosensitive drum 21. A power supply (not shown) is connected to the developing roller 204, and a developing bias voltage is applied. The toner carried on the developing roller 204 moves to the photosensitive drum 21 in the vicinity of the photosensitive drum 21 by electrostatic force due to the developing bias voltage.

  The doctor blade 206 is a rectangular plate-like member extending in the axial direction of the developing roller 204, one end in the width direction is fixed to the developing tank 201, and the other end is provided at a distance from the surface of the developing roller 204. It is done. An interval (doctor gap) between the doctor blade 206 and the developing roller 204 is, for example, 0.4 mm to 2.0 mm. The doctor blade 206 is provided at a distance from the surface of the developing roller 204, thereby restricting the amount of developer carried on the developing roller 204 to a predetermined amount. Examples of the material of the doctor blade 206 include stainless steel, aluminum, and synthetic resin.

  The partition wall 207 is a member that extends along the longitudinal direction of the developing tank 201 at a substantially central portion in the width direction of the developing tank 201. The partition wall 207 is provided between the bottom wall portion 201 c of the developing tank 201 and the developing tank cover 205, and is provided so that both end portions in the longitudinal direction are separated from the side wall portions 201 a and 201 b of the developing tank 201. The partition 207 divides the internal space of the developing tank 201 into a first conveyance path P, a second conveyance path Q, a first communication path R, and a second communication path S.

  The second transport path Q is a substantially semi-cylindrical space extending along the longitudinal direction of the partition wall 207 and is a space facing the developing roller 204. The first transport path P is a substantially semi-cylindrical space extending along the longitudinal direction of the partition wall 207 and is a space facing the second transport path Q across the partition wall 207. The first communication path R is a space that communicates the first transport path P and the second transport path Q on the longitudinal end 207a side of the partition wall 207. The second communication path S is a space that communicates the first transport path P and the second transport path Q on the side of the other end 207 b in the longitudinal direction of the partition wall 207.

  In the bottom wall 201c of the developing tank 201, the developer surface exceeds a predetermined height in the first direction Z (vertical direction) in which the bottom of the developing tank 201 is the bottom and the ceiling of the developing tank 201 is the top. A discharge port 201d is formed to discharge the developer beyond the amount of the developer tank 201 from time to time. In the present embodiment, the discharge port 201d is formed facing the portion of the first transport path P that is continuous with the first communication path R. Further, the first direction Z of the present embodiment is a vertical direction.

  The developing tank cover 205 is a ceiling part of the developing tank 201, is detachably provided above the developing tank 201 in the vertical direction, and has a supply port 205a. A developer supply pipe 250 is connected to the developer tank cover 205 at a supply port 205a. The supply port 205a is an opening in which an opening for supplying the two-component developer to the developing tank 201 is formed. The two-component developer housed in the developer cartridge 300 is connected to the developer supply pipe 250 and It is supplied into the developing tank 201 through this opening.

  The supply port 205a is provided in the vicinity of the second communication path S in the vertical direction above the first transport path P. More specifically, the opening formed in the supply port portion 205 a is provided so as to face the first transport path P and be at the same position as the second communication path S in the longitudinal direction of the partition wall 207.

  The first transport member 202 is provided in the first transport path P. The first conveying member 202 conveys the developer in the developing tank 201 from the other end 207b in the longitudinal direction of the partition wall 207 toward the one end 207a in the longitudinal direction. Hereinafter, the developer conveyance direction by the first conveyance member 202 is referred to as a second direction X1. The second direction X1 is a direction perpendicular to the first direction Z, and is also a direction from the second communication path S toward the first communication path R.

  The first transport member 202 is an auger screw-like member including a first rotating shaft member 202a, a first spiral blade 202b, and a first gear 202c. The first rotating shaft member 202a is a cylindrical member having a diameter of 4 mm to 10 mm, and is connected to the first gear 202c at the downstream end in the second direction X1. The first rotating shaft member 202a is rotatably supported around the axis by a bearing (not shown) fixed to the side wall 201a of the developing tank 201 and a bearing (not shown) fixed to the side wall 201b of the developing tank 201. A first spiral blade 202b that is a member that spirally surrounds the side surface is provided on the side surface of the first rotating shaft member 202a.

  The 1st rotating shaft member 202a, the 1st spiral blade 202b, and the 1st gear 202c are formed from resin materials, such as polyethylene, a polypropylene, high impact polystyrene, ABS resin, for example. The first rotating shaft member 202a, the first spiral blade 202b, and the first gear 202c are preferably integrally formed from the same material.

The first conveying member 202 is rotated at 150 rpm to 400 rpm around the axis of the first rotating shaft member 202a via the first gear 202c by a rotation driving source such as a motor (not shown) provided in the image forming apparatus 100. To do. At this time, the first spiral blade 202b rotates around the axis of the first rotating shaft member 202a. Specifically, the first direction Z portion located on top of the first spiral blade 202b is away from the partition wall 207, rotational movement in the rotational direction _{G 1} closer to the bottom wall portion 201c of the developer tank 201. As a result of such rotational movement, the developer stored in the first transport path P is transported downstream in the second direction X1. As described above, the supply port 205a of the developer tank cover 205 is formed in the vicinity of the second communication path S above the first transport path P in the vertical direction, so that the unused two components in the developer cartridge 300 are formed. The developer is first supplied to the first transport path P, and then transported downstream of the first transport path P in the second direction X1 by the first transport member 202.

The first spiral blade 202b is provided in a position that does not face the discharge port 201d in the second direction X1, and is provided in a position that faces the discharge port 201d, and the large diameter spiral blade 202ba, 202bb. , 202bc and a small-diameter spiral blade 202bd whose outer diameter is smaller than that of 202bc. A large-diameter spiral blade 202bc is provided downstream of the small-diameter spiral blade 202bd in the second direction X1, a large-diameter spiral blade 202bb is provided upstream in the second direction X1, and a large-diameter spiral blade 202ba is further provided upstream. It is done. Diameter spiral blade 202 ba, 202 bb, the outer diameter _{L 1} of 202bc is, for example, 20Mm～30mm, the outer diameter _{L 2} of the small-diameter spiral blade 202bd is, for example, 7Mm～12mm.

The large diameter spiral blade 202bb has a multiple spiral structure. Here, the multiple spiral structure means that a plurality of spiral blades are arranged at the same position in the axial direction of the first rotating shaft member 202a and different positions in the circumferential direction of the first rotating shaft member 202a. Refers to the structure surrounding the side. In the present embodiment, the large-diameter spiral blade 202bb has a double spiral structure including two spiral blades, but more preferably has a triple or more spiral structure. In the present embodiment, the length of the large-diameter spiral blade 202bb in the second direction X1 is larger than the length of the discharge port 201d in the second direction X1 (length L ₇ shown in FIG. 10 described later).

  The second transport member 203 is provided in the second transport path Q. The second transport member 203 transports the developer in the developing tank 201 from the longitudinal direction one end 207a side of the partition wall 207 toward the longitudinal other end 207b side. Hereinafter, the developer conveyance direction by the second conveyance member 203 is referred to as a direction X2.

  The second conveying member 203 is an auger screw-like member including a second rotating shaft member 203a, a second spiral blade 203b, and a second gear 203c. The second rotating shaft member 203a is a cylindrical member having a diameter of 4 mm to 10 mm, and is connected to the second gear 203c at the upstream end in the direction X2. The second rotating shaft member 203a is supported so as to be rotatable around the axis by a bearing (not shown) fixed to the side wall 201a of the developing tank 201 and a bearing (not shown) fixed to the side wall 201b of the developing tank 201.

A second spiral blade 203b that is a member that spirally surrounds the side surface is provided on the side surface of the second rotating shaft member 203a. The outer diameter L3 of the second spiral blade 203b is, for example, 20 mm to ₃₀ mm.

  The 2nd rotating shaft member 203a, the 2nd spiral blade 203b, and the 2nd gear 203c are formed from resin materials, such as polyethylene, a polypropylene, high impact polystyrene, ABS resin, for example. The second rotary shaft member 203a, the second spiral blade 203b, and the second gear 203c are preferably integrally formed from the same material.

The second conveying member 203 is rotated at 150 rpm to 400 rpm around the axis of the second rotating shaft member 203a via the second gear 203c by a rotation driving source such as a motor (not shown) provided in the image forming apparatus 100. To do. At this time, the second spiral blade 203b rotates around the axis of the second rotating shaft member 203a. Specifically, the first direction Z part positioned at the top of the second helical blade 203b is away from the partition wall 207, rotational movement in the rotational direction _{G 2} to approach the bottom wall portion 201c of the developer tank 201. As a result of such rotational movement, the two-component developer stored in the second conveyance path Q is conveyed downstream in the direction X2.

  The toner density detection sensor 208 is mounted at the bottom of the developing tank 201 below the second transport member 203 in the vertical direction so that the sensor surface is exposed to the second transport path Q. The toner concentration detection sensor 208 is electrically connected to a toner concentration control unit (not shown).

  The toner density control unit performs control to rotate the developer discharge member 303 and supply the toner into the developing tank 201 in accordance with the toner density detection result detected by the toner density detection sensor 208. More specifically, the toner density control unit determines whether or not the toner density detection result by the toner density detection sensor 208 is lower than a predetermined set value. A control signal is sent to the drive unit to be rotated, and the developer discharge member 303 is rotated for a predetermined period.

  A power source (not shown) is connected to the toner concentration detection sensor 208. The power supply applies to the toner concentration detection sensor 208 a drive voltage for driving the toner concentration detection sensor 208 and a control voltage for outputting the toner concentration detection result to the toner concentration control unit. Application of a voltage to the toner concentration detection sensor 208 by the power supply is controlled by a control unit (not shown).

  As the toner concentration detection sensor 208, a general toner concentration detection sensor can be used. For example, a transmitted light detection sensor, a reflected light detection sensor, a magnetic permeability detection sensor, or the like can be used. Among these toner concentration detection sensors, it is preferable to use a magnetic permeability detection sensor. Examples of the magnetic permeability detection sensor include TS-L (trade name, manufactured by TDK Corporation), TS-A (trade name, manufactured by TDK Corporation), TS-K (trade name, manufactured by TDK Corporation), and the like. It is done.

  The guide member 209 is provided in a space facing the discharge port 201d in the first transport path P and the second transport path Q, that is, in the first transport path P in the present embodiment. The guide member 209 forms a hollow body together with a portion surrounding the discharge port 201d in the bottom wall portion 201c of the developing tank 201. This hollow body is a hollow body in which a discharge port 201d is formed in a side wall portion and a lower end portion in at least the first direction Z is opened, like a hollow body T1 and a hollow body T2 shown in FIG. In the present embodiment, the upper end portion in the first direction Z of the guide member 209 is in contact with the developing tank cover 205, and therefore the upper end portion in the first direction Z of the hollow body is not open. When the length of the hollow body in the first direction Z is sufficiently long so that the toner and the carrier scattered by the first spiral blade 202b of the first conveying member 202 do not leak from the discharge port 201d, the first direction Z The upper end may be open. In this case, the upper end portion in the first direction Z of the guide member 209 is separated from the developing tank cover 205.

  The guide member 209 is a member that guides a part of the two-component developer transported in the second direction X1 by the first transport member 202 in the first direction Z and discharges it from the discharge port 201d. More specifically, a part of the two-component developer conveyed in the second direction X1 is an opening at the lower end portion in the first direction Z of the hollow body formed by the guide member 209 and the bottom wall portion 201c of the developing tank 201. Then, it passes through the inside of the hollow body, moves upward in the first direction Z, and is discharged from the discharge port 201d formed in the side wall portion of the hollow body. At this time, the two-component developer moving in the first direction Z is flattened by the pressing force generated by the weight of the two-component developer or the weight of the two-component developer outside the hollow body. Is done. As a result, the height difference of the developer surface in the first direction Z is suppressed, and a part of the two-component developer is discharged from the discharge port 201d in a state where the height difference is suppressed.

  The waste developer transport container 210 is a container for storing the toner and the carrier discharged from the discharge port 201d and guiding them to the waste developer recovery container 212, and includes a waste developer transport member 211 therein. The waste developer transport container 210 communicates with the developing tank 201 through the discharge port 201d. In addition, the waste developer transport container 210 communicates with the waste developer collection container 212 via a second discharge port 210a formed at the bottom.

  The waste developer conveying member 211 is an auger screw-like member including a columnar rotating shaft member and a spiral blade surrounding the rotating shaft member. The waste developer transport member 211 transports the toner and carrier discharged from the discharge port 201d and stored in the waste developer transport container 210 toward the second discharge port 210a, and discharges the toner and carrier from the second discharge port 210a.

  The waste developer collection container 212 is a container for storing the toner and carrier discharged from the second discharge port 210a, and communicates with the waste developer transport container 210 through a receiving port 212a formed in the upper part. . The waste developer collection container 212 is configured to be detachable from the waste developer transport container 210. The waste developer collection container 212 has a sensor (not shown) inside. When the waste developer collection container 212 is filled with toner or carrier, this sensor senses, and as a result, the image forming apparatus 100 notifies the user. In contrast, the fact that the waste developer collection container 212 is full is notified. Thus, the user can replace the waste developer collection container 212 when the waste developer collection container 212 becomes full.

  According to the developing device 200 configured as described above, in the developing tank 201, the two-component developer contains the first transport path P, the first communication path R, the second transport path Q, the second communication path S, It is circulated and conveyed in the order. A part of the two-component developer circulated and conveyed is carried on the surface of the developing roller 204 in the second conveyance path Q, and the toner in the carried two-component developer moves to the photosensitive drum 21. Are consumed sequentially. When the toner concentration detection sensor 208 detects that a predetermined amount of toner has been consumed, unused toner and carrier are supplied from the developer cartridge 300 into the first transport path P. The supplied toner and carrier are transported in the first transport path P and diffused in the already stored two-component developer. As a result, the toner concentration of the two-component developer stored in the developing tank 201 increases, and the volume of the two-component developer stored in the developing tank 201 increases. When the bulk of the two-component developer increases, excess two-component developer is discharged from the discharge port 201d. As a result, the deteriorated toner and carrier are discharged instead of unused toner and carrier. be able to.

  Since the developing device 200 includes the guide member 209 that flattens the developer surface, the two-component development is performed in a state where the height difference in the first direction Z of the developer surface is suppressed and the height difference is suppressed. The agent can be discharged from the discharge port 201d. Thereby, even when the fluidity of the two-component developer is lowered and the developer surface is wavy, variation in the amount of developer discharged from the discharge port 201d can be suppressed. Therefore, the developing device 200 can balance the amount of the two-component developer supplied and the amount of the two-component developer discharged.

In the present embodiment, the small diameter spiral blade 202bd is provided at a position facing the discharge port 201d in the first conveying member 202, and the large diameter spiral blades 202ba, 202bb, 202bc are provided at a position not facing the discharge port 201d. Diameter spiral blade 202bd and large diameter spiral blade 202 ba, 202 bb, 202bc is friction by displacing the two-component developer in the first direction Z vertical during rotation, relatively small diameter helical blade 202bd outer diameter _{L 2} is The distance from the developer surface is relatively long, and the developer surface is relatively difficult to cause undulation. Therefore, the small-diameter spiral blade 202bd can displace the two-component developer in the first direction Z up and down while suppressing the undulation of the developer surface, thereby forming a hollow formed by the guide member 209 and the developing tank 201. When the two-component developer moving inside the body is a lump, the lump can be crushed and reliably discharged from the discharge port 201d. As another embodiment of the present invention, the small diameter spiral blade 202bd may not be provided.

  In this embodiment, since the large-diameter spiral blade 202bb having a multiple spiral structure is provided upstream of the discharge port 201d in the second direction X1, when the developer surface is wavy, the wave pitch is narrowed. As a result, the guide member 209 can facilitate the flattening. As another embodiment of the present invention, the first conveying member 202 may not include a spiral blade having a multiple spiral structure.

  Further, in the present embodiment, the discharge port 201d is formed facing the portion that communicates with the first communication path R on the downstream side in the second direction X1 of the first conveyance path P where the first conveyance member 202 is provided. This portion is a portion where the two-component developer conveyed by the first conveying member 202 is likely to stay, and the discharge port 201d is formed facing such a portion where the two-component developer tends to stay, It is possible to easily discharge the two-component developer from the discharge port 201d in a state where the undulation of the developer surface is suppressed. As another embodiment of the present invention, the discharge port 201d may be formed facing the upstream portion or the center portion in the second direction X1 of the first transport path P, or the second transport path Q. It may be formed on the face.

In this embodiment also, the first spiral blade 202b is a portion positioned in the first direction Z uppermost rotational movement in the rotational direction G ₁ closer to the bottom wall portion 201c of the developer tank 201, thereby, the second direction X1 The two-component developer is conveyed to The present invention has the guide member 209 is provided around the discharge opening 201d, the although the two-component developer as compared with the case where not provided becomes difficult to be discharged, the first spiral blade 202b rotation direction G ₁ By rotating, the two-component developer easily moves to the vicinity of the discharge port 201d. As a result, the two-component developer can be reliably discharged when the volume of the two-component developer increases. As another embodiment of the present invention, the first spiral blade 202b may be configured to transport the two-component developer in the rotational movement in the opposite direction to the rotation direction G _1.

  In the present embodiment, the toner and carrier are supplied from the developer cartridge 300 to the developing device 200 at the same time. However, in another embodiment of the present invention, a toner cartridge is used instead of the developer cartridge 300. In addition, a carrier cartridge may be provided so that the toner and the carrier are individually supplied to the developing device 200.

  Next, the guide member 209 of this embodiment will be described in detail. FIG. 9 is a perspective view of the guide member 209. FIG. 10 is an enlarged view showing a part of FIG.

  The guide member 209 includes an upstream plate 209a, a downstream plate 209b, and a connection plate 209c. The upstream plate 209a is a rectangular plate-like member that has a main surface perpendicular to the second direction X1 and is provided on the upstream side of the discharge port 201d in the second direction X1. The downstream plate 209b is a rectangular plate-like member that has a main surface perpendicular to the second direction X1 and is provided downstream of the discharge port 201d in the second direction X1. The connection plate 209c is a rectangular plate member that has a main surface parallel to the second direction X1 and connects the upstream plate 209a and the downstream plate 209b.

  The rectangular main surfaces of the upstream plate 209a and the downstream plate 209b have two sides extending in the first direction Z and a direction perpendicular to the first direction Z and the second direction X1 (hereinafter referred to as “third direction Y”). ) To the two sides. The rectangular main surface of the connection plate 209c is formed by two sides extending in the first direction Z and two sides extending in the second direction X1. As shown in FIGS. 4 and 6, one end portion in the third direction Y of the upstream plate 209 a and the downstream plate 209 b is fixed to the bottom wall portion 201 c of the developing tank 201, and the other end portion in the third direction Y is connected to the partition wall 207. They are provided with a space therebetween and are connected by a connection plate 209c.

  Thus, since the upstream plate 209a of the guide member 209 extends perpendicularly to the second direction X1, the two-component developer transported by the first transport member 202 can be easily retained, thereby transporting the two-component developer transported. When the developer surface of the developer is wavy, the height difference in the first direction Z of the developer surface can be suppressed. Further, since the downstream plate 209b of the guide member 209 extends perpendicularly to the second direction X1, when the two-component developer moves in the direction opposite to the second direction X1, the two-component developer is dammed and discharged. It is possible to prevent the two-component developer from being undesirably discharged from the outlet 201d. Further, since the connecting plate 209c of the guide member 209 extends in the second direction X1, the flow of the two-component developer conveyed in the second direction X1 is not hindered. In another embodiment of the present invention, the upstream plate 209a, the downstream plate 209b, and the connection plate 209c may be curved plate-like members.

  The upstream plate 209a, the downstream plate 209b, and the connection plate 209c are formed of a resin material such as polyethylene, polypropylene, high impact polystyrene, and ABS resin, for example. The upstream plate 209a, the downstream plate 209b, and the connection plate 209c are preferably integrally formed from the same material. Furthermore, it is more preferable that it is integrally formed with the bottom wall 201c of the developing tank 201.

In the present embodiment, the upstream plate 209a and the downstream plate 209b have the same length in the third direction Y. The length _{L 4} are shown in Figure 4, it is set to 30% to 60% of the length _{L 5} in the third direction Y of the first conveying path P, in the present embodiment, it is 7Mm～18mm.

Further, in the present embodiment, the length _{L 6} in the second direction X1 of the connection plate 209c is set to 150% to 250% of the length _{L 7} in the second direction X1 of the discharge port 201d, in this embodiment, 15 mm to 25 mm. The upstream plate 209a is provided 2 mm to 8 mm away from the discharge port 201d in the second direction X1, and the downstream plate 209b is provided 2 mm to 8 mm away from the discharge port 201d in the second direction X1.

Further, in the present embodiment, the upstream plate 209a is provided such that the lower end portion in the first direction Z is higher in the first direction Z than the lower end portion in the first direction Z of the discharge port 201d. The first direction Z lower end of the upstream plate 209a and the first direction Z lower end of the outlet 201d, the distance _{L 8} in the first direction Z, the 20% of the length _{L 9} in the first direction Z of the discharge port 201d It is set to ˜50%, and in this embodiment, it is 2 mm to 5 mm. Thus, by providing the upstream plate 209a such that the lower end portion in the first direction Z of the upstream plate 209a is higher in the first direction Z than the lower end portion in the first direction Z of the discharge port 201d, the upstream plate 209a can be reliably removed from the discharge port 201d. The two-component developer is discharged, and the effect of preventing deterioration due to compression of the two-component developer is obtained.

This effect will be described with reference to FIG. FIG. 11A shows that the first direction Z lower end portion of the upstream plate 209a and the first direction Z lower end portion of the downstream plate 209b are lower in the first direction Z than the first direction Z lower end portion of the discharge port 201d. is a diagram showing an example in which the. As described above, the two-component developer conveyed in the second direction X1 is discharged from the discharge port 201d through the hollow body T1 formed by the guide member 209 and the bottom wall portion 201c. The hollow body T1 has a shape in which the lower end portion in the first direction Z is opened and the discharge port 201d is formed in the side wall portion. If the fluidity of the two-component developer is slightly reduced, The two-component developer can be reliably discharged from the discharge port 201d through the opening at the lower end in the direction Z. However, when the fluidity of the two-component developer is extremely reduced, a part of the two-component developer that rises in the first direction Z inside the hollow body T1 through the opening at the lower end of the first direction Z is However, it remains undischarged from the discharge port 201d, further rises with the replenishment of a new two-component developer, reaches the developing tank cover 205, and may be compressed.

  Therefore, in the present embodiment, as shown in FIG. 11 (b), the first direction Z lower end portion of the upstream plate 209a is located above the first direction Z lower end portion of the discharge port 201d in the first direction Z. The two-component developer is prevented from being compressed. Thus, the hollow body T2 formed by shortening the length of the upstream plate 209a in the first direction Z has an opening at the lower end of the first direction Z, a discharge port 201d formed in the side wall portion, and further, the upstream plate It becomes the shape where the notch was formed below the 1st direction Z of 209a. As a result, the communication portion between the space inside the hollow body T2 and the space outside the hollow body T2 is increased, and the two-component developer can easily move. Therefore, the first direction Z of the two-component developer in the hollow body T2 is increased. The height at is lowered. As a result, even when the fluidity of the two-component developer is extremely reduced, the two-component developer can be reliably discharged from the discharge port 201d, and the two-component developer is compressed and deteriorated thereby. Can be prevented.

In the present embodiment, the downstream plate 209b is provided such that the lower end portion in the first direction Z is lower in the first direction Z than the lower end portion in the first direction Z of the discharge port 201d. The first direction Z lower end of the downstream plate 209b to the first direction Z lower end of the outlet 201d, the distance _{L 10} in the first direction Z, 20% of the length _{L 9} in the first direction Z of the discharge port 201d It is set to ˜50%, and in this embodiment, it is 2 mm to 5 mm. Thus, by providing the downstream plate 209b so that the lower end of the first direction Z of the downstream plate 209b is lower in the first direction Z than the lower end of the first direction Z of the discharge port 201d, the discharge port 201d is provided with the downstream plate 209b. The effect of preventing the two-component developer from falling into the snow is obtained.

  This effect will be described with reference to FIG. As described above, the discharge port 201d is formed facing the downstream portion of the first transport path P in the second direction X1, and the guide member 209 is formed in the downstream portion of the first transport path P in the second direction X1. Is provided. In this portion, as shown in FIG. 12, the two-component developer D tends to stay and the developer surface is higher in the first direction Z. Therefore, if the downstream plate 209b is not provided, or if the lower end of the first direction Z of the downstream plate 209b is higher in the first direction Z than the lower end of the first direction Z of the discharge port 201d, the two-component developer D Falls into the outlet 201d. However, in the present embodiment, the lower end in the first direction Z of the downstream plate 209b is positioned below the lower end in the first direction Z of the discharge port 201d in the first direction Z. That is, since the downstream plate 209b is provided extending below the discharge port 201d in the first direction Z, the staying two-component developer D can be blocked by the downstream plate 209b, and the two-component developer D can be prevented from falling into the discharge port 201d.

  In the present embodiment, the length of the connection plate 209c in the first direction Z is equal to the length of the downstream plate 209b in the first direction Z. In other words, the lower end portion in the first direction Z of the connection plate 209c is located lower in the first direction Z than the lower end portion in the first direction Z of the discharge port 201d, and the connection 209 plate c is in the first direction Z. It is provided extending below the discharge port 201d. If the first direction Z lower end portion of the connection plate 209c is above the first direction Z lower end portion of the discharge port 201d in the first direction Z, when the toner or carrier is scattered by the first spiral blade 202b, These may be undesirably discharged from the discharge port 201d. On the other hand, in the present embodiment, since the connection plate 209c is provided to extend below the discharge port 201d in the first direction Z, the scattered toner or carrier is prevented from reaching the discharge port 201d. And unwanted discharge of toner and carrier can be prevented.

  In the image forming apparatus 100 including the developing device 200 configured as described above, the developing device 200 suppresses the variation in the amount of the two-component developer to be discharged, and as a result, the amount of the two-component developer to be supplied is discharged. Therefore, it is possible to form a high-quality image.

DESCRIPTION OF SYMBOLS 20 Toner image formation part 30 Transfer part 40 Fixing part 50 Recording medium supply part 60 Discharge part 100 Image forming apparatus 200,200b, 200c, 200m, 200y Developing apparatus 201 Developing tank 201d Discharge port 202 1st conveyance member 202a 1st rotating shaft Member 202b first spiral blade 202ba, 202bb, 202bc large diameter spiral blade 202bd small diameter spiral blade 204 developing roller 205 developing tank cover 207 partition 209 guide member 209a upstream plate 209b downstream plate 209c connecting plate 250, 250b, 250c, 250m, 250y development Agent supply pipe 300, 300b, 300c, 300m, 300y Developer cartridge

Claims (5)

In the developing device for developing the electrostatic latent image on the image carrier by supplying the developer to the image carrier,
A developer tank for storing developer, when the developer surface exceeds a predetermined height in the vertical direction with the bottom of the developer tank at the bottom and the ceiling at the top. A developing tank in which a discharge port for discharging out of the developing tank is formed;
A transport member that transports the developer in the developer tank in a transport direction that intersects the vertical direction;
A guide member that forms a hollow body together with a part of the developing tank surrounding the discharge port,
The hollow body is a hollow body in which the discharge port is located in a side wall portion and a lower end portion in the vertical direction is opened.
The guide member is
An upstream plate extending perpendicularly to the transport direction and provided upstream of the discharge port in the transport direction;
A downstream plate extending perpendicularly to the transport direction and provided downstream of the discharge port in the transport direction;
A connection plate extending in the transport direction and connecting the upstream plate and the downstream plate;
The upstream plate is provided such that a lower end portion in the vertical direction is on the upper side in the vertical direction with respect to a lower end portion in the vertical direction of the discharge port.
The guide member guides a part of the developer transported in the transport direction by the transport member to the upper side in the vertical direction through the opening and discharges the developer from the discharge port. . The developing tank includes a partition, and by the partition, the first transport path along the longitudinal direction of the partition, the second transport path facing the first transport path across the partition, and the one end in the longitudinal direction of the partition A first communication path that communicates the first conveyance path and the second conveyance path, and a second communication path that communicates the first conveyance path and the second conveyance path at the other longitudinal end of the partition wall. And
The conveying member is
A rotating shaft member, and a spiral blade that surrounds the rotating shaft member and rotates as the rotating shaft member rotates about the axis, from one of the first communication path and the second communication path A spiral blade provided so that the direction toward the other is the transport direction,
Provided in one of the first transport path or the second transport path;
The discharge port is formed so as to face a portion connected to the other of the first communication path or the second communication path of the one of the first conveyance path or the second conveyance path,
The guide member is provided on the one of the first transport path and the second transport path,
The developing device according to claim 1 , wherein the downstream plate is provided such that a lower end portion in the vertical direction is located on a lower side in the vertical direction with respect to a lower end portion in the vertical direction of the discharge port. The spiral blade includes a large-diameter spiral blade provided at a position not facing the discharge port, and a small-diameter spiral blade provided at a position facing the discharge port and having an outer diameter smaller than that of the large-diameter spiral blade. The developing device according to claim 2 , wherein: The spiral blade, in the transport direction upstream side of the discharge port, a developing device according to claim 2 or 3, characterized by having a multiple helix configuration. In an electrophotographic image forming apparatus,
An image forming apparatus comprising: a developing device according to any one of claims 1-4.

Images