Image forming apparatus and developing unit

Abstract

To provide one new form for supplying toner by air.SOLUTION: An image forming apparatus comprises: a photoconductor drum; a toner storage unit for storing toner; a developing roller; and a cyclone separator that is provided with an intake port, a first outlet communicated with the inside of the toner storage unit, and a second outlet communicated with the outside of the toner storage unit, and is configured to take in air mixed with toner from the intake port and separate the toner and air from each other, and exhaust the separated toner and air from the first outlet and the second outlet, respectively. In a direction of a rotation axis, the first outlet is provided at a position between both ends of a toner carrying unit in the direction of the rotation axis.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus that forms an image on a recording material, and a developing unit used in the image forming apparatus. [Background technology]

[0002] In an electrophotographic image forming apparatus, the toner contained in the toner container (developing container) of the developing device is consumed during image formation, so the toner is replenished from a toner container that contains replenishment toner to the toner container. Patent Document 1 describes a configuration in which the toner is transported from the toner container to the developing device by an air flow generated by an air pump. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2000-81778 A Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 discloses a configuration in which a filter for discharging air is provided on a path through which air containing toner flows toward a developing device.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a new method for replenishing toner with air. [Means for solving the problem]

[0006] One aspect of the present invention is an image forming apparatus comprising: a photosensitive drum; a toner storage section for storing toner, the toner storage section configured so that toner is replenished using air; a developing roller rotating about a rotation axis, the developing roller having a toner carrying section that carries the toner stored in the toner storage section, and supplying the toner carried on the toner carrying section to the photosensitive drum; and a cyclone separator having an intake port, a first discharge port leading to the inside of the toner storage section, and a second discharge port leading to the outside of the toner storage section, the cyclone separator configured to take in air mixed with toner from the intake port, separate the toner and air, and discharge the separated toner and air from the first discharge port and the second discharge port, respectively, wherein the first discharge port is provided at a position between both ends of the toner carrying section in the direction of the rotation axis.

[0007] Another aspect of the present invention is an image forming apparatus including a photosensitive drum, a toner storage unit for storing toner, the toner storage unit configured to allow toner to be replenished using air, a developing roller that rotates about a rotation axis, the developing roller having a toner carrying unit that carries the toner stored in the toner storage unit, the developing roller supplying the toner carried on the toner carrying unit to the photosensitive drum, an intake port, a first discharge port that leads to the inside of the toner storage unit, and a second discharge port that leads to the outside of the toner storage unit, and the air mixed with toner is discharged from the intake port. and a cyclone separator configured to take in toner, separate it from toner and air, and discharge the separated toner and air from the first discharge outlet and the second discharge outlet, respectively, wherein the cyclone separator is provided on an upper surface of the toner storage unit, the cyclone separator has a truncated cone portion formed in a truncated cone shape whose radius decreases downward, the first discharge outlet is provided at a lower end of the truncated cone portion, and at least a portion of the truncated cone portion protrudes downward from a top surface of the interior of the toner storage unit.

[0008] Another aspect of the present invention is a developing unit for use in an image forming apparatus, comprising: a toner storage section for storing toner, the toner storage section configured to allow toner to be replenished using air; a developing roller that rotates about a rotation axis, the developing roller having a toner carrying section that carries the toner stored in the toner storage section, the developing roller for supplying the toner carried on the toner carrying section to a photosensitive drum; and a cyclone separator having an intake port, a first discharge port leading to the inside of the toner storage section, and a second discharge port leading to the outside of the toner storage section, the cyclone separator configured to take in air mixed with toner from the intake port, separate the toner and the air, and discharge the separated toner and air from the first discharge port and the second discharge port, respectively, wherein the first discharge port is provided at a position between both ends of the toner carrying section in the direction of the rotation axis. Effect of the Invention

[0009] According to the present invention, a new method for replenishing toner by air can be provided. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic diagram of an image forming apparatus according to a first embodiment. [Diagram 2] 1A to 1C are perspective views of an image forming apparatus according to a first embodiment. [Diagram 3] 1A and 1B are perspective views of an image forming unit according to the first embodiment. [Figure 4] 2A and 2B are top views of an image forming unit according to the first embodiment. [Diagram 5] 1A and 1B are cross-sectional views of an image forming unit according to the first embodiment. [Figure 6] FIG. 2 is a diagram showing a state in which the image forming unit according to the first embodiment is pulled out. [Figure 7] 1A is a front view, FIG. 1B is a top view, FIG. 1C is a bottom view, FIG. 1D is a side view, and FIG. 1E is a rear view of a cartridge according to a first embodiment. [Figure 8] 1A is a cross-sectional view, FIG. 1B is a perspective view, and FIG. 1C is an exploded perspective view of a cartridge according to a first embodiment. [Figure 9] 1A is a cross-sectional view of a cartridge according to a first embodiment, and FIG. [Figure 10] 1A is a front view, FIG. 1B is a top view, FIG. 1C is a bottom view, FIG. 1D is a left side view, and FIG. [Figure 11] 1A is a cross-sectional view, FIG. 1B is an exploded perspective view, and FIG. 1C is a cross-sectional view of a cyclone according to a first embodiment. [Figure 12] FIG. 11 is a perspective view of an image forming unit according to a modified example. [Figure 13] FIG. 2 is a cross-sectional view of a development unit according to the first embodiment. [Figure 14] FIG. 11 is a perspective view of an image forming unit according to a second embodiment. [Figure 15] FIG. 11 is a top view of an image forming unit according to a second embodiment. [Figure 16] 13A and 13B are cross-sectional views of a developing unit according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following description, the X direction, the Y direction, and the Z direction are preferably perpendicular to each other.

[0012] First Embodiment An overview of an image forming apparatus 1 according to a first embodiment will be described with reference to Fig. 1. Fig. 1 shows a cross section of the image forming apparatus 1 cut along a plane perpendicular to the main scanning direction (the direction of the rotation axis of the photosensitive drum 4). The image forming apparatus 1 of this embodiment is a full-color printer capable of forming a full-color image on a recording material S using four colors of toner as a developer. As the recording material (recording medium) S, a variety of sheet materials of different sizes and materials can be used, including paper such as plain paper and cardboard, surface-treated sheet materials such as coated paper, sheet materials of special shapes such as envelopes and index paper, plastic films, cloth, etc.

[0013] The image forming apparatus 1 includes process units PY, PM, PC, and PK (hereinafter, each process unit P) and an apparatus main body 72. Here, each process unit P is arranged to be aligned in a first direction (hereinafter, referred to as the X direction), and the color of toner contained therein is different from each other. The longitudinal direction of each process unit P is a second direction (hereinafter, referred to as the Y direction) perpendicular to the X direction. The process units PY, PM, PC, and PK are referred to as the first process unit, second process unit, third process unit, and fourth process unit, respectively.

[0014] Each process unit P has a process means (process element) for the electrophotographic process. The process means is a unit that acts on an image carrier or a recording material to perform any one of the steps of the electrophotographic process, namely, charging, exposing, developing, transferring, cleaning, and fixing. A rotational driving force is transmitted to each process unit P from a drive output section of the apparatus main body 72. A bias voltage (charging bias, developing bias, etc.) is also supplied to each process unit P from a power supply circuit of the apparatus main body 72.

[0015] As shown in FIG. 1, the process units PY, PM, PC, and PK are provided with drum units 8Y, 8M, 8C, and 8K (hereinafter, each drum unit 8). Each drum unit 8 has a photosensitive drum 4Y, 4M, 4C, and 4K (hereinafter, each photosensitive drum 4), and a charging roller 5Y, 5M, 5C, and 5K (hereinafter, each charging roller 5) as a process means acting on each photosensitive drum 4. Each photosensitive drum 4 functions as an image carrier that carries a latent image and a toner image. Each photosensitive drum 4 is an electrophotographic photosensitive body having a photosensitive layer formed of an organic photosensitive material or the like on the outer periphery of a cylindrical base. Each photosensitive drum 4 is arranged so that the direction of their rotation axis is the Y direction. The photosensitive drums 4Y, 4M, 4C, and 4K are the first photosensitive drum, the second photosensitive drum, the third photosensitive drum, and the fourth photosensitive drum, respectively.

[0016] Each process unit P includes developing units 9Y, 9M, 9C, and 9K (hereinafter referred to as each developing unit 9) having developing rollers 6Y, 6M, 6C, and 6K (hereinafter referred to as each developing roller 6) that develop the electrostatic latent images on the corresponding photosensitive drums 4. Each developing unit 9 is aligned in the X direction. The developing rollers 6Y, 6M, 6C, and 6K are respectively referred to as the first developing roller, the second developing roller, the third developing roller, and the fourth developing roller. The developing units 9Y, 9M, 9C, and 9K are respectively referred to as the first developing unit, the second developing unit, the third developing unit, and the fourth developing unit.

[0017] Each of the developing units 9 includes a developing container 3Y, 3M, 3C, or 3K (hereinafter, each of the developing containers 3). Each of the developing containers 3 is a toner storage section that stores toner to be used for development by each of the developing rollers 6. Each of the developing rollers 6 has an outer circumferential surface that serves as a toner carrying section that carries the toner stored in each of the developing containers 3 (toner storage sections). Each of the developing rollers 6 is a developer carrying member that develops a latent image on each of the photosensitive drums 4 (on an image carrying member) into a toner image using the toner carried on the outer circumferential surface. Each of the developing rollers 6 may be a cylindrical member (also called a developing sleeve).

[0018] The developing unit 9Y has a developing container 3Y (first developing container) that contains yellow (Y) toner (first toner), and is configured so that the yellow toner is supplied to the surface of the photosensitive drum 4Y by a developing roller 6Y that carries the yellow toner. The developing unit 9M has a developing container 3M (second developing container) that contains magenta (M) toner (second toner), and is configured so that the magenta toner is supplied to the surface of the photosensitive drum 4M by a developing roller 6M that carries the magenta toner. The developing unit 9C has a developing container 3C (third developing container) that contains cyan (C) toner (third toner), and is configured so that the cyan toner is supplied to the surface of the photosensitive drum 4C by a developing roller 6C that carries the cyan toner. The developing unit 9K has a developing container 3K (fourth developing container) that contains black (K) toner (fourth toner), and is configured so that the black toner is supplied to the surface of the photosensitive drum 4K by a developing roller 6K that carries the black toner.

[0019] In a third direction (hereinafter referred to as Z direction) intersecting both the X direction and the Y direction, a laser scanner unit LB (exposure unit) is provided above each process unit P (each photosensitive drum 4). This laser scanner unit LB outputs laser light corresponding to image information. Hereinafter, the optical paths of the laser light toward the photosensitive drums 4Y, 4M, 4C, and 4K are referred to as LY, LM, LC, and LK (hereinafter referred to as each optical path L or optical path L). The laser light passes through exposure windows 10Y, 10M, 10C, and 10K of the laser scanner unit LB to scan and expose the surface of each photosensitive drum 4. An LED exposure unit may be used instead of the laser scanner unit LB.

[0020] The Z direction is preferably parallel to the vertical direction (the direction of gravity) when the image forming apparatus 1 is installed on a horizontal surface. Furthermore, unless otherwise specified, "downward" refers to one side of the Z direction (the downward direction in FIG. 1), and "upward" refers to the other side of the Z direction (the upward direction in FIG. 1).

[0021] Below the process unit P in the Z direction, an intermediate transfer belt unit 11 is provided as a transfer member (intermediate transfer unit). The intermediate transfer belt unit 11 has a transfer belt 12, a drive roller 14, a tension roller 13, and an assist roller 15. The transfer belt 12 is flexible, and is stretched around the drive roller 14, the tension roller 13, and the assist roller 15.

[0022] The lower surface of each photosensitive drum 4 contacts the upper surface of the transfer belt 12. The contact portion between each photosensitive drum 4 and the transfer belt 12 is a primary transfer portion 30Y, 30M, 30C, 30K (hereinafter referred to as a primary transfer portion 30). On the inner side of the transfer belt 12, primary transfer rollers 16Y, 16M, 16C, 16K (hereinafter referred to as a transfer roller 16) are provided to face each photosensitive drum 4.

[0023] A secondary transfer roller 17 is pressed against the drive roller 14 via the transfer belt 12. The contact portion between the transfer belt 12 and the secondary transfer roller 17 is a secondary transfer portion 31.

[0024] A feeding unit 18 is provided below the intermediate transfer belt unit 11 in the Z direction. The feeding unit 18 has a feeding tray 19 that stacks and accommodates the recording material S, and a feeding roller 20 that picks up the recording material S from the feeding tray 19 and transports it.

[0025] A fixing unit 21 for fixing a toner image to the recording material S and a discharge roller 22 for discharging the recording material S with the fixed toner image to a discharge tray 23 are provided at the top of the device main body 72 in FIG. 1. The discharge roller 22 discharges the recording material S in a direction along the X direction. In this embodiment, the downstream side of the discharge direction in which the recording material S is discharged toward the discharge tray 23 by the discharge roller 22 is the front side or FE side of the image forming device 1, and the upstream side of the discharge direction is the rear side or BE side of the image forming device 1. In addition, the right side when the image forming device 1 is viewed from the front side is the right side or RE side of the image forming device 1, and the left side when the image forming device 1 is viewed from the front side is the left side or LE side of the image forming device 1. In this embodiment, the RE side is one side in the Y direction, and the LE side is the other side in the Y direction opposite to the RE side.

[0026] [Image formation operation] The image forming operation for forming a full-color image is as follows: Each photosensitive drum 4 is rotated counterclockwise at a predetermined speed in Fig. 1. The transfer belt 12 is rotated in a direction (the direction of arrow C in Fig. 1) following the rotation of each photosensitive drum 4 at a speed corresponding to the rotation speed of each photosensitive drum 4.

[0027] The laser scanner unit LB is also driven. In synchronization with the driving of the laser scanner unit LB, the charging roller 5 in each process unit P uniformly charges the surface of each corresponding photosensitive drum 4 to a predetermined polarity and potential. The laser scanner unit LB scans and exposes the surface of each charged photosensitive drum 4 with a laser beam in accordance with an image signal of each color, and forms an electrostatic latent image on the surface of each photosensitive drum 4 in accordance with the image signal of each color. That is, the laser scanner unit LB exposes the photosensitive drum 4Y and the photosensitive drum 4M, and forms a first electrostatic latent image and a second electrostatic latent image on the photosensitive drum 4Y and the photosensitive drum 4M, respectively. Similarly, the laser scanner unit LB exposes the photosensitive drum 4C and the photosensitive drum 4K, and forms a third electrostatic latent image and a fourth electrostatic latent image on the photosensitive drum 4C and the photosensitive drum 4K, respectively.

[0028] The electrostatic latent image on each photosensitive drum 4 is developed by supplying toner to each photosensitive drum 4 by each developing roller 6 that is driven to rotate clockwise in FIG. 1 at a predetermined speed. By the electrophotographic image forming process described above, a yellow toner image is formed on the photosensitive drum 4Y of the process unit PY. Then, the yellow toner image is primarily transferred onto the transfer belt 12. Similarly, a magenta toner image is formed on the photosensitive drum 4M of the process unit PM. Then, the magenta toner image is primarily transferred onto the transfer belt 12 so as to be superimposed on the yellow toner image on the transfer belt 12. A cyan toner image is formed on the photosensitive drum 4C of the process unit PC. Then, the cyan toner image is primarily transferred onto the transfer belt 12 so as to be superimposed on the yellow and magenta toner images on the transfer belt 12. A black toner image is formed on the photosensitive drum 4K of the process unit PK. Then, the black toner image is primarily transferred onto the transfer belt 12 so as to be superimposed on the yellow, magenta, and cyan toner images on the transfer belt 12.

[0029] In this way, a full-color unfixed toner image of four colors, yellow, magenta, cyan, and black, is formed on the transfer belt 12. Meanwhile, at a predetermined control timing, the recording material S is separated one by one from the feed tray 19 by the feed roller 20 and fed. The recording material S is introduced into the secondary transfer section 31, which is the contact portion between the secondary transfer roller 17 and the transfer belt 12, at a predetermined control timing. In the process of the recording material S being conveyed through the secondary transfer section 31, the four-color superimposed toner image on the transfer belt 12 is transferred onto the recording material S. The recording material S onto which the toner image has been transferred is heated and pressurized by the fixing unit 21, and the toner image is fixed onto the recording material S. The recording material S onto which the toner image has been fixed is discharged to the discharge tray 23 by the discharge roller 22.

[0030] [cartridge] The image forming apparatus 1 has cartridges 430Y, 430M, 430C, and 430K (hereinafter, each cartridge 430) as a supply pack detachable from the apparatus main body 72. In this embodiment, the apparatus main body 72 is a portion of the image forming apparatus 1 excluding the cartridges 430Y, 430M, 430C, and 430K. Each cartridge 430 is aligned in the Y direction. That is, each cartridge 430 is aligned in a direction intersecting (perpendicular to) the direction in which each development unit 9 is aligned. The cartridges 430Y, 430M, 430C, and 430K are respectively a first cartridge (first toner container), a second cartridge (second toner container), a third cartridge (third toner container), and a fourth cartridge (fourth toner container).

[0031] Fig. 2(a) is a perspective view of the image forming apparatus 1 with the front door 72b closed. Fig. 2(b) is a perspective view of the image forming apparatus 1 with the front door 72b open. Fig. 2(c) is a perspective view of the image forming apparatus 1 with the front door 72b open and the cartridge 430M removed from the cartridge holder 429.

[0032] The device main body 72 has a housing 72a and a front door 72b as an opening / closing member that can be opened and closed relative to the housing 72a. The housing 72a accommodates the process units P, the laser scanner unit LB, the intermediate transfer belt unit 11, the fixing unit 21, etc. The cartridges 430 are attached to the upper part of the front side of the device main body 72 so that the cartridges 430 can be accessed by opening the front door 72b. In other words, the cartridges 430 are provided at the downstream end of the housing 72a in the discharge direction of the discharge roller 22.

[0033] The front door 72b is configured to be movable between a closed position (see FIG. 2(a)) where it closes the opening of the device body 72 on the front side, and an open position (see FIG. 2(b)) where it opens the opening. When the front door 72b is moved to the open position, as shown in FIG. 2(b), each cartridge 430 is exposed to the outside of the image forming apparatus 1 through the opening. The cartridges 430 are arranged side by side in the Y direction, and are configured to be detachable from the device body 72 in the X direction, as shown in FIG. 2(c). This allows each process unit P to be moved between the closed position and the open position without removing the process unit P from the device body 72. Toner can be replenished to the cartridges 430. By arranging each cartridge 430 on the front side of the image forming apparatus 1, each cartridge 430 can be accessed from the front side, in the same way as when collecting the recording material S discharged to the discharge tray 23. In addition, since the cartridge holder 429 is located on the front side of the image forming apparatus 1, the process unit P is not exposed even after each cartridge 430 is removed (see FIG. 2(c)). Each cartridge 430 is stored in the space inside the apparatus main body 72 (the space between the housing 72a and the front door 72b) when the front door 72b is closed.

[0034] As shown in FIG. 2(a), indicators 208Y, 208M, 208C, and 208K (hereinafter, each indicator 208) (marking section, display section) of each color are provided on the front side of the image forming apparatus 1. Each indicator 208 is arranged in the Y direction so as to correspond to each cartridge 430. Indicator 208Y (first indicator) is yellow, and indicator 208M (second indicator) is magenta. Indicator 208C (third indicator) is cyan, and indicator 208K (fourth indicator) is black. Each indicator 208 is composed of an LED or a sticker of a color corresponding to the color of the toner of each cartridge, and is provided to prevent each cartridge 430 from being erroneously installed. In addition, each indicator 208 may have a function of displaying the remaining amount of toner of each corresponding process unit P (each developing unit 9).

[0035] [Image forming unit] The toner transport mechanism from each cartridge 430 to the corresponding process unit P will be described with reference to FIGS.

[0036] A unit including each cartridge 430, each process unit P, and a transport path for transporting toner from each cartridge 430 to each process unit P, which will be described later, is referred to as an image forming unit 500.

[0037] Fig. 3(a) is a perspective view of the image forming unit 500 with each cartridge 430 attached. Fig. 3(b) is a perspective view of the image forming unit 500 with each cartridge 430 removed. Fig. 4(a) is a top view of the laser scanner unit LB and the image forming unit 500. Fig. 4(b) is a top view of the image forming unit 500. Figs. 5(a) and (b) are cross sections taken along lines AA and BB of Fig. 4(a), respectively.

[0038] As shown in FIG. 3(a), pump units 80Y, 80M, 80C, and 80K (hereinafter, referred to as pump units 80) are provided below the cartridge holder 429. The pump units 80 are aligned in the Y direction. The pump units 80Y, 80M, 80C, and 80K are the first pump unit, the second pump unit, the third pump, and the fourth pump unit, respectively. A positive displacement pump such as a reciprocating pump or a rotary pump is used for each pump unit 80. The reciprocating pump is a pump that performs suction and discharge by the reciprocating motion of a piston or a plunger, and includes a piston pump, a plunger pump, and a diaphragm pump. The rotary pump is a pump that performs suction and discharge by rotating a gear or a rotor, and includes a gear pump, a screw pump, and a vane pump. The four pump units may be configured as one pump unit. In this embodiment, the pump units 80 are provided in the image forming unit 500, but may be provided in each cartridge 430 or the apparatus main body 72.

[0039] The "air" discharged by each pump unit 80 does not have to be a gas with the same composition as the atmosphere, and may be, for example, air from which water vapor or oxygen has been removed. Also, each pump unit 80 may be configured to discharge nitrogen supplied from, for example, a liquid nitrogen tank as "air."

[0040] As shown in Fig. 3(b) and Fig. 5(a), the cartridge holder 429 has an opening at a portion facing the lower surface of each cartridge 430, through which the discharge ports 80Ya, 80Ma, 80Ca, and 80Ka (hereinafter, each of the discharge ports 80a) are exposed. Air generated by each pump unit 80 is discharged from each of the discharge ports 80a. Each of the discharge ports 80a opens upward.

[0041] The air discharged upward from each outlet 80a is supplied to the inside of each cartridge 430 attached to the cartridge holder 429. The air supplied to the inside of each cartridge 430 is discharged from each cartridge 430 to the outside together with the toner. That is, air containing toner (air mixed with toner; mixed fluid containing air and toner) is discharged from each cartridge 430. The internal structure of each cartridge 430 will be described later, so will not be described in detail here.

[0042] The air containing toner discharged from each cartridge 430 is received by supply pipes 444Y, 444M, 444C, and 444K through receiving ports 429Ya, 429Ma, 429Ca, and 429Ka provided in the cartridge holder 429 shown in Fig. 3(b). Hereinafter, the receiving ports 429Ya, 429Ma, 429Ca, and 429Ka will be referred to as the respective receiving ports 429a. Also, the supply pipes 444Y, 444M, 444C, and 444K will be referred to as the respective supply pipes 444.

[0043] Each supply pipe 444 extends to each developing unit 9 and is connected thereto. Each receiving port 429a is a through hole provided to penetrate the surface of the cartridge holder 429 facing the rear surface of each cartridge 430. Each receiving port 429a opens toward the X direction in which the developing units 9 are lined up. The opening direction of each receiving port 429a intersects with the opening direction of each ejection port 80a.

[0044] 4(b), upstream ends 444Yu, 444Mu, 444Cu, and 444Ku (hereinafter, referred to as upstream ends 444u) of the supply pipes 444 are disposed on the rear side of the portion where the receiving ports 429a of the cartridge holder 429 are provided. Each upstream end 444u is connected to the cartridge holder 429 so as to communicate with the corresponding receiving port 429a.

[0045] The toner received through each receiving port 429a is transported inside each supply pipe 444 by air discharged from each cartridge 430. The toner is moved from each upstream end 444u to downstream ends 444Yd, 444Md, 444Cd, and 444Kd (hereinafter referred to as each downstream end 444d) of each supply pipe 444, and is supplied to each developing unit 9.

[0046] Each developing container 3, which is a container for storing toner T in each developing unit 9, is provided with cyclones CyY, CyM, CyC, and CyK (hereinafter, each cyclone Cy) on the upper surface. Each cyclone Cy separates air from the air containing toner supplied to each developing container 3 and discharges it outside each developing container 3, while supplying toner T to each developing container 3. The internal structure of each cyclone Cy will be described later, so will not be described in detail here.

[0047] Each downstream end 444d of each supply pipe 444 is connected to each cyclone Cy at the end of each developer container 3 in the Y direction. Specifically, a downstream end 444Yd of the supply pipe 444Y and a downstream end 444Md of the supply pipe 444M are connected to a cyclone CyY at the LE end of the developer container 3Y and a cyclone CyM at the LE end of the developer container 3M, respectively. A downstream end 444Cd of the supply pipe 444C and a downstream end 444Kd of the supply pipe 444K are connected to a cyclone CyC at the RE end of the developer container 3C and a cyclone CyK at the RE end of the developer container 3K, respectively.

[0048] Due to such a connection relationship between each supply pipe 444 and each cyclone CyC, it is possible to reduce pressure loss by shortening the length of each supply pipe 444. In addition, since the pressure loss is small, it is possible to select small pump units 80, and the image forming unit 500 can be made smaller.

[0049] The image forming unit 500 is preferably configured to allow easy access to the process unit P and the supply pipe 444 for maintenance and replacement of the process unit P and the supply pipe 444 in the event of a breakdown or other such service. Therefore, in this embodiment, the image forming unit 500 is configured to be able to be pulled out from the BE side (rear side) to the FE side (front side) with respect to the apparatus main body 72. Also, in this embodiment, the image forming unit 500 is configured to be able to be pulled out from the BE side (rear side) to the FE side (front side) with respect to the intermediate transfer belt unit 11. FIG. 6 shows a state in which the image forming unit 500 is pulled out from the apparatus main body 72. Note that the image forming apparatus 1 may be configured such that the image forming unit 500 cannot be pulled out.

[0050] Also, each cyclone Cy is preferably configured to be easily accessible for maintenance. Therefore, in this embodiment, when the image forming unit 500 is pulled out from the BE side (rear side) to the FE side (front side) of the apparatus main body 72, each cyclone Cy is configured to be exposed to the outside of the apparatus main body 72. That is, when the image forming unit 500 is pulled out to the FE side, each cyclone Cy protrudes toward the FE side (front side) from an opening 72a1 (FIG. 2(b)) provided on the FE side end face 72aF of the housing 72a. The opening 72a1 is provided on the end face 72aF so as to enable the image forming unit 500 to be pulled out and inserted. Also, in this embodiment, the attachment and detachment of each cartridge 430 to the apparatus main body 72 is performed through the opening 72a1.

[0051] [Cartridge structure] The structure of each cartridge 430 of this embodiment will be described with reference to Figure 3(a) and Figures 7(a) to 9(b). Each cartridge 430 is an example of a toner container.

[0052] As shown in FIG. 3A, the width La of the cartridge 430K in the Y direction is greater than the width Lb of the cartridges 430Y, 430M, and 430C. Therefore, the volume for storing toner of the cartridge 430K is greater than the volumes of the cartridges 430Y, 430M, and 430C. By allowing the cartridge 430K to store more black toner, which is generally consumed in larger quantities, than the other colors, the number of times the cartridges 430Y, 430M, 430C, and 430K are replaced is more likely to be equalized. In this embodiment, the widths Lb of the cartridges 430Y, 430M, and 430C in the Y direction are the same, but they may be different from each other.

[0053] Except for the difference in width in the Y direction, the structure of each cartridge 430 is the same. Therefore, the following will describe the structure of cartridge 430Y, and will omit descriptions of the structures of cartridges 430M, 430C, and 430K.

[0054] 7(a), (b), (c), (d), and (e) are respectively a front view, a top view, a bottom view, a right side view, and a rear view of the cartridge 430Y. FIG. 8(a) is a cross-sectional view taken along line HH of FIG. 7(e). FIG. 8(b) is a perspective view of the cartridge 430Y. FIG. 8(c) is an exploded perspective view of the cartridge 430Y. FIG. 9(a) is a cross-sectional view taken along line GG of FIG. 7(b). FIG. 9(b) is a perspective view of FIG. 9(a). Note that the following description of the structure of the cartridge 430Y is given in a state (position) in which the cartridge 430Y is attached to the cartridge holder 429.

[0055] As shown in FIGS. 8(a) to 8(c), the cartridge 430Y has a first frame 430Ya, a second frame 430Yb, a filter 83Y (first filter, first ventilation member), and a discharge pipe 85Y (first discharge pipe, first passage). Although not shown, the cartridge 430M also has a third frame corresponding to the first frame 430Ya and a fourth frame corresponding to the second frame 430Yb. The cartridge 430M also has a filter (second filter, second ventilation member) corresponding to the filter 83Y, and a discharge pipe (second discharge pipe, second passage) corresponding to the discharge pipe 85Y. The cartridge 430C also has a fifth frame corresponding to the first frame 430Ya and a sixth frame corresponding to the second frame 430Yb. The cartridge 430C also has a filter (third filter, third ventilation member) corresponding to the filter 83Y, and a discharge pipe (third discharge pipe, third passage) corresponding to the discharge pipe 85Y. Similarly, the cartridge 430K also has a seventh frame corresponding to the first frame 430Ya, and an eighth frame corresponding to the second frame 430Yb. The cartridge 430K also has a filter (fourth filter, fourth ventilation member) corresponding to the filter 83Y, and a discharge pipe (fourth discharge pipe, fourth passage) corresponding to the discharge pipe 85Y.

[0056] Although the first frame body 430Ya and the second frame body 430Yb in this embodiment are members molded from resin, they may be formed from paper, etc. As shown in Fig. 7(e), an outlet 430Ya1 (first outlet) is provided on the rear surface 4300Ya of the first frame body 430Ya.

[0057] As shown in FIG. 7(c), a receiving port 430Yb1 (first receiving port, first intake port) is provided on the bottom surface 4300Yb of the second frame 430Yb. It is preferable to provide the discharge port 430Ya1 and the receiving port 430Yb1 on the surface of the cartridge 430Y except for the surface (facing the Y direction) intersecting with the Y direction in which the cartridges 430 are aligned. This makes it possible to reduce the gaps Gym, Gmc, and Gck between the cartridges 430 shown in FIG. 3(a). As a result, the widths La and Lb of the cartridges 430 can be increased, so that the volume for storing toner can be increased. The gap Gym is the gap between the cartridge 430Y and the cartridge 430M in the Y direction. The gap Gmc is the gap between the cartridge 430M and the cartridge 430C in the Y direction. The gap Gck is the gap between the cartridge 430C and the cartridge 430K in the Y direction.

[0058] The discharge port 430Ya1 is provided on the rear surface 4300Ya (the end surface on the downstream side in the mounting direction of the cartridge 430Y) of the cartridge 430Y so as to open toward the downstream side in the mounting direction. Therefore, when the cartridge 430Y is mounted on the cartridge holder 429, the discharge port 430Ya1 can be easily engaged so as to communicate with the receiving port 429Ya of the cartridge holder 429. The discharge port 430Ya1 may be provided on the bottom surface 4300Yb or the top surface of the cartridge 430Y, and the receiving port 430Yb1 may be provided on the rear surface 4300Ya or the top surface. If there is sufficient space in the device main body 72, the discharge port 430Ya1 and the receiving port 430Yb1 may be provided on a surface intersecting the Y direction. Although not shown, the cartridge 430M has a discharge port (second discharge port) and a receiving port (second receiving port, second intake port) in the same arrangement as the cartridge 430Y. Cartridge 430C has an outlet (third outlet) and an inlet (third inlet, third inlet) in the same arrangement as cartridge 430Y. Cartridge 430K has an outlet (fourth outlet) and an inlet (fourth inlet, fourth inlet) in the same arrangement as cartridge 430Y.

[0059] The discharge port 430Ya1 may be provided with a sealing member (seal or shutter) (not shown). When the cartridge 430Y is not attached to the cartridge holder 429 of the apparatus main body 72, the sealing member seals the discharge port 430Ya1 to prevent the toner T contained therein from leaking out of the cartridge 430Y. When the cartridge 430Y is attached to the cartridge holder 429, the sealing member is removed or moved so that the discharge port 430Ya1 is opened.

[0060] 7(a) is for indicating the color of the toner inside the cartridge 430Y. The label 430Ys may be an instruction showing how to mount the cartridge 430Y in the cartridge holder 429, or may indicate some other information related to the cartridge 430Y.

[0061] As shown in Figures 8(a) to 8(c), the first frame 430Ya and the second frame 430Yb have a flange portion 430Ya2 and a flange portion 430Yb2, respectively. The flange portion 430Ya2 and the flange portion 430Yb2 are ultrasonically welded to each other to form an internal space SPY of the cartridge 430Y shown in Figure 8(a). The flange portion 430Ya2 and the flange portion 430Yb2 may be fixed to each other with an adhesive or screws.

[0062] The filter 83Y is provided so as to partition (separate) the internal space SPY of the cartridge 430Y into two, a toner chamber 430Yc (first chamber) and an air chamber 430Yd (second chamber). That is, the air chamber 430Yd is adjacent to the toner chamber 430Yc via the filter 83Y. Although not shown, the cartridge 430M is provided with a filter that partitions (separates) the internal space of the cartridge 430M into two, a toner chamber (third chamber) and an air chamber (fourth chamber). That is, the air chamber of the cartridge 430M is adjacent to the toner chamber via the filter. The cartridge 430C is provided with a filter that partitions (separates) the internal space of the cartridge 430C into two, a toner chamber (fifth chamber) and an air chamber (sixth chamber). That is, the air chamber of the cartridge 430C is adjacent to the toner chamber via the filter. The cartridge 430K includes a filter that divides the internal space of the cartridge 430K into two chambers, a toner chamber (chamber 7) and an air chamber (chamber 8). In other words, the air chamber of the cartridge 430K is adjacent to the toner chamber via the filter.

[0063] The toner chamber 430Yc is located above the air chamber 430Yd and is aligned with the air chamber 430Yd in the Z direction. In other words, the cartridge 430Y is mounted in the apparatus main body 72 in a position in which the toner chamber 430Yc is above the air chamber 430Yd. The alignment direction of the toner chamber 430Yc and the air chamber 430Yd is the Z direction. Therefore, in this embodiment, the receiving port 430Yb1 opens toward this alignment direction, and the discharge port 430Ya1 opens in a direction intersecting this alignment direction.

[0064] The toner chamber 430Yc is configured to accommodate the toner T. In the toner chamber 430Yc, the toner T is supported by the filter 83Y.

[0065] No toner is stored in the air chamber 430Yd. The filter 83Y is made of a porous material made of, for example, resin fibers, and has a size and density of holes that allow air to pass through and prevent toner from passing through. In other words, the filter 83Y is configured to allow air to pass through and prevent toner from passing through. As shown in Figs. 8 and 9, the outer edge 83Ya of the filter 83Y is sandwiched between the flange 430Ya2 of the first frame 430Ya and the flange 430Yb2 of the second frame Yb, and is held by the first frame 430Ya and the second frame 430Yb. The filter 83Y is inclined from the outer edge 83Ya toward the lowest part 83Yb, which is located below the outer edge 83Ya. In other words, the filter 83Y has a portion (inclined portion) that is inclined downward as it approaches (closes to) the lowest part 83Yb in the X direction, Y direction, or horizontal direction.

[0066] The lowest portion 83Yb is a portion that protrudes from the outer edge portion 83Ya in the direction from the toner chamber 430Yc toward the air chamber 430Yd. As shown in Figures 8(a) and 9(b), the lowest portion 83Yb is provided in the center of the filter 83Y in the X and Y directions. The filter 83Y used is one that is molded into the shape described above.

[0067] The toner chamber 430Yc is provided with a discharge pipe 85Y (passage). Although the discharge pipe 85Y in this embodiment is a member molded with resin, it may be formed of paper, rubber, or the like. The discharge pipe 85Y is a pipe having an inlet 85Ya (first opening) and an outlet 85Yb (second opening) and extending from the inlet 85Ya to the outlet 85Yb. The discharge pipe 85Y is a passage through which the toner T accommodated in the toner chamber 430Yc passes when it is moved toward the discharge port 430Ya1. The discharge pipe 85Y has a first portion 85Y1 having the inlet 85Ya and extending in the Z direction, and a second portion 85Y2 having the outlet 85Yb and extending in the X direction. The direction in which the first portion 85Y1 extends and the direction in which the second portion 85Y2 extends intersect (perpendicular to each other in this embodiment).

[0068] The outlet 85Yb of the discharge pipe 85Y is connected to communicate with the discharge port 430Ya1. The inlet 85Ya of the discharge pipe 85Y is arranged to face the lowest part 83Yb, which is a part of the filter 83Y, with a gap therebetween. It is preferable that the inlet 85Ya is close to the filter 83Y. When the remaining amount of toner T in the toner chamber 430Yc becomes small, the toner T fluidized by the air received from the receiving port 430Yb1 moves along the inclination of the filter 83Y described above and gathers at the lowest part 83Yb. The inlet 85Ya of the discharge pipe 85Y can guide the toner T gathered at the lowest part 83Yb of the filter 83Y to the discharge port 430Ya1. As a result, even when the remaining amount of toner contained in the toner chamber 430Yc of the cartridge 430Y becomes small, the toner T can be efficiently discharged to the outside of the cartridge 430Y.

[0069] The cartridge of this embodiment has a structure in which toner is discharged to the outside of the cartridge by air, and does not require a rotating member such as a screw, etc. Therefore, the cartridge can have a simple structure with a small number of parts.

[0070] [Cyclone structure] The structure of each cyclone Cy in this embodiment will be described with reference to Figures 10 and 11. Since the structure of each cyclone Cy is the same except for the direction in which the toner flows, only the structure of cyclone CyY will be described here, and descriptions of the structures of cyclones CyM, CyC, and CyK will be omitted.

[0071] 10(a), (b), (c), (d), and (e) are respectively a front view, a top view, a bottom view, a left side view, and a right side view of the cyclone CyY. FIG. 11(a) is a cross-sectional view taken along the line JJ in FIG. 10(b). FIG. 11(b) is an exploded perspective view showing the cross-section JJ of the cyclone CyY. FIG. 11(c) is a cross-sectional view taken along the line KK in FIG. 10(a). The following description of the structure of the cyclone CyY is given in the state (position) in which it is attached to the main body 72 of the apparatus. FIG. 10(a) shows a schematic diagram of the developing container 3Y (toner storage section) to which toner is replenished via the cyclone CyY. FIG. 11(a) shows a virtual straight line representing the central axis Ax of the truncated cone section CyYb1. FIG. 11(c) shows an imaginary line passing through the central axis Ax and extending in the X direction, and an imaginary line passing through the central axis Ax and extending in the Y direction, as a reference for showing an example of the arrangement of elements related to the cyclone CyY.

[0072] As shown in Figures 10(a) to 10(e) and 11(a) to 11(c), the cyclone CyY has a cylindrical member CyYa (upper member, receiving side member) as a first member, a truncated cone member CyYb (lower member, discharge side member) as a second member, and an exhaust filter CyYf. The cylindrical member CyYa has an inlet CyYa1, a cylindrical portion CyYa2, and an exhaust port CyYa3. The truncated cone member CyYb has a truncated cone portion CyYb1 and a toner discharge port CyYb2.

[0073] The cyclone CyY is a separation device (cyclone separator, centrifugal separator) that receives air containing toner to be replenished to the developing container 3Y (toner storage unit) and separates the toner from the air by centrifugal separation. The cyclone CyY has a toner discharge port CyYb2 as a first discharge port for discharging the toner into the internal space of the toner storage unit, and an exhaust port CyYa3 as a second discharge port for discharging the air into the external space of the toner storage unit.

[0074] The cyclone CyY receives air containing toner through an inlet CyYa1, and performs centrifugation by generating a swirling flow of air in the internal space between a cylindrical portion CyYa2 and a truncated cone portion CyYb1. The cylindrical portion CyYa2 and the truncated cone portion CyYb1 are the main body of the cyclone CyY, which form the space in which the swirling flow of air containing toner occurs. The cyclone CyY discharges the toner separated from the air by the centrifugation from a toner discharge port CyYb2, and discharges the air separated from the toner by the centrifugation from an exhaust port CyYa3 and an exhaust filter CyYf.

[0075] In the following description, the direction along the central axis Ax of the truncated cone portion CyYb1 is defined as the axial direction (axial direction) of the cyclone CyY. In this embodiment, the axial direction of the cyclone CyY is substantially parallel to the Z direction (gravity direction), but the cyclone CyY may be disposed so that the axial direction intersects obliquely with the Z direction. In addition, the radial direction of a virtual circle centered on the central axis Ax when the cyclone CyY is viewed in the axial direction is defined as the radial direction of the cyclone CyY.

[0076] The cyclone CyY of this embodiment is a tangential type in which the inlet CyYa1 is connected to the outer wall of the cylindrical portion CyYa2 so as to be in contact with it. That is, as shown in FIG. 11(c), the radius of the cylindrical portion CyYa2 relative to the central axis Ax is constant. Also, the wall surface of the inlet CyYa1 on the radially far side from the central axis Ax extends along the tangent of the cylindrical portion CyYa2 at the connection portion CyYa12 (boundary portion) between the inlet CyYa1 and the cylindrical portion CyYa2.

[0077] The cyclone CyY is not limited to the tangential inflow type, and may be a type in which the radius of the cylindrical portion CyYa2 is not constant, such as a semicircular spiral type (hemispiral) or a full-circular spiral type (spiral). In the semicircular spiral type, the radius of the cylindrical portion CyYa2 gradually decreases over a range of 180 degrees around the central axis Ax from the connection portion of the cylindrical portion CyYa2 and the inlet CyYa1. In the full-circular spiral type, the radius of the cylindrical portion CyYa2 gradually decreases over a range of 360 degrees around the central axis Ax from the connection portion of the cylindrical portion CyYa2 and the inlet CyYa1.

[0078] As shown in FIG. 11(a)(b), the cylindrical portion CyYa2 of the cylindrical member CyYa and the truncated cone portion CyYb1 of the truncated cone member CyYb are aligned in the Z direction. The lower portion of the cylindrical portion CyYa2 is connected to the upper portion of the truncated cone portion CyYb1. The cylindrical portion CyYa2 is cylindrical and centered on a central axis line Ax extending in the Z direction. The truncated cone portion CyYb1 is a truncated cone shape centered on the central axis line Ax, and is formed into a truncated cone shape with a radius that decreases downward. The toner discharge port CyYb2 (first discharge port) is formed at the lower end (lower end portion) of the truncated cone portion CyYb1.

[0079] The lower part of the cylindrical member CyYa and the lower part of the truncated cone member CyYb are fixed without any gap so that toner does not leak from the connection part between the cylindrical part CyYa2 and the truncated cone part CyYb1 to the outside of the cyclone CyY and the developing container 3Y. The fixing method is, for example, an adhesive, but ultrasonic welding or screw fastening may also be used. More specifically, in this embodiment, an annular convex part CyYb3 (FIGS. 11(a) and 11(b)) provided on the upper part of the truncated cone member CyYb is fitted into an annular concave part CyYa5 provided on the lower part of the cylindrical member CyYa. The upper end surface of the convex part CyYb3 is in contact with the upper end surface of the concave part CyYa5, and the outer surface of the convex part CyYb3 in the radial direction faces the inner surface of the concave part CyYa5 in the radial direction. In this manner, by fixing the cylindrical member CyYa and the truncated cone member CyYb in a state in which a part of the cylindrical portion CyYa2 and a part of the truncated cone portion CyYb1 overlap in the Z direction, toner leakage can be more reliably reduced. Note that a recess may be provided on the upper part of the truncated cone member CyYb, and a protrusion that fits into the recess may be provided on the lower part of the cylindrical member CyYa.

[0080] The inlet CyYa1 is an intake port (receiving portion, receiving port) that takes in air containing toner. The inlet CyYa1 is a cylindrical portion extending along a tangential direction at a certain point on the inner wall surface of the cylindrical portion CyYa2 shown in FIG. 11(c). In this embodiment, the inlet CyYa1 extends from an end position in the X direction of the inner wall surface of the cylindrical portion CyYa2 to one side in the Y direction (LE side). The inlet CyYa1 opens in a direction from the center to the end of the corresponding developing roller 6Y in the direction of the rotation axis of the developing roller 6Y.

[0081] The exhaust port CyYa3 is an opening (second exhaust port) that leads to the outside of the developing container 3Y (toner storage section). The exhaust port CyYa3 is an opening for discharging air from which the toner has been separated from the air-fuel mixture to the outside of the cyclone CyY. The exhaust port CyYa3 is provided at the upper part (upper end, upper end surface) of the cylindrical section CyYa2. The exhaust port CyYa3 of this embodiment opens to the upper surface of the cylindrical section CyYa2. The exhaust port CyYa3 of this embodiment opens upward. The exhaust port CyYa3 of this embodiment is located above the upper surface (outer surface of the cover member 3Y1) of the developing container 3Y (toner storage section).

[0082] The exhaust port CyYa3 is provided at the upper end (second end) of the tubular portion CyYa30 extending downward from the upper surface of the cylindrical portion CyYa2 along the central axis Ax. The lower end CyYa31 (first end) of the tubular portion CyYa30 where the exhaust port CyYa3 is provided opens into the space inside the cylindrical portion CyYa2 and the truncated cone portion CyYb1 (see also FIG. 13). The lower end CyYa31 of the tubular portion CyYa30 is located below the top surface (the lower surface of the cover member 3Y1) of the internal space of the developing container 3Y and above the toner discharge port CyYb2 (first discharge port) of the cyclone CyY. That is, the cyclone CyY of this embodiment has the tubular portion CyYa30 extending downward from the exhaust port CyYa3 (second discharge port). The lower end CyYa31 of the cylindrical portion CyYa30 opens into the internal space of the cyclone CyY formed by the cylindrical portion CyYa2 and the truncated cone portion CyYb1. At least a part of the cylindrical portion CyYa30 is provided at the same position as the inlet CyYa1 in the direction of the central axis Ax. In other words, at least a part of the cylindrical portion CyYa30 is provided at a position overlapping with the inlet CyYa1 when viewed in a direction perpendicular to the central axis Ax.

[0083] The cylindrical portion CyYa30 has a function of preventing the air flow that flows from the inlet CyYa1 along the inner wall surface of the cylindrical portion CyYa2 into the internal space of the cyclone CyY before the toner is centrifuged from approaching the exhaust port CyYa3. This can further increase the clogging prevention effect of the exhaust filter CyYf described below. However, the configuration may be such that the cylindrical portion CyYa30 is not provided. This is because the air mixed with the toner tends to flow downward due to the weight of the toner itself, and is unlikely to flow toward the exhaust port CyYa3 (exhaust filter CyYf) provided above.

[0084] The exhaust filter CyYf is attached to the upper surface of the cylindrical member CyYa. The exhaust filter CyYf is provided so as to cover the exhaust port CyYa3 when viewed from above, and allows air to be discharged from the exhaust port CyYa3 and collects toner. In other words, the exhaust filter CyYf allows air to pass through and prevents toner from passing through. A space (chamber) formed by the chamber part CyYc is provided between the exhaust port CyYa3 and the exhaust filter CyYf. The chamber part CyYc has a concave shape in which a part of the upper surface of the cylindrical member CyYa (a part including the periphery of the exhaust port CyYa3) is concave downward. The chamber is formed as a space surrounded by the bottom part of the concave shape, the raised part around the bottom part (the part where the exhaust filter CyYf is attached), and the exhaust filter CyYf.

[0085] The cross-sectional area of ​​the space (chamber) formed by the chamber part CyYc perpendicular to the Z direction is larger than the cross-sectional area of ​​the exhaust port CyYa3 on a plane perpendicular to the Z direction. In other words, the cross-sectional area of ​​the space formed by the chamber part CyYc perpendicular to the extension direction of the cylindrical part CyYa30 having the exhaust port CyYa3 at the upper end is larger than the cross-sectional area of ​​the cross-sectional area perpendicular to the extension direction of the cylindrical part CyYa30. Therefore, the effective surface area of ​​the exhaust filter CyYf can be made larger than that of a configuration in which the exhaust port CyYa3 directly faces the exhaust filter CyYf. The effective surface area of ​​the exhaust filter CyYf is the area of ​​the region of the exhaust filter CyYf through which air can pass from the inside to the outside of the cyclone CyY. If the total amount of toner particles attached to the exhaust filter CyYf is the same, the exhaust filter CyYf with a larger effective surface area is less likely to become clogged. The effective surface area of ​​the exhaust filter CyYf in this embodiment is the surface area of ​​the portion of the exhaust filter CyYf that is exposed to the chamber part CyYc.

[0086] The toner discharge port CyYb2 is an opening (first discharge port) that leads to the inside of the developing container 3Y (toner storage section). The toner discharge port CyYb2 is an opening for discharging the toner separated from the air to the outside of the cyclone CyY. The toner discharge port CyYb2 is formed at the lower end of the truncated cone section CyYb1. The toner discharge port CyYb2 of this embodiment has a circular shape centered on the central axis line Ax. The toner discharge port CyYb2 opens to the space inside the developing container 3Y (the storage space that stores the toner used for image formation) (FIG. 10(a)). The toner discharge port CyYb2 of this embodiment opens downward. The toner discharge port CyYb2 of this embodiment is located below the top surface (the inner surface of the cover member 3Y1) inside the developing container 3Y (toner storage section).

[0087] In this embodiment, the truncated cone member CyYb of the cyclone CyY is integrally formed with the cover member 3Y1 (FIG. 11(b)) that forms the upper surface of the developing container 3Y, using resin. That is, in this embodiment, at least the truncated cone portion CyYb1 of the cyclone CyY is integrally formed with the upper surface of the developing container 3Y (toner storage portion). "Integraly formed" refers to being formed as a single part by a method such as injection molding or cutting of a resin material. The truncated cone member CyYb and the cover member 3Y1 may be parts integrally formed with a single resin material.

[0088] In this embodiment, the developing container 3Y includes a main body frame 3Y2 (FIG. 10(a)) that is open upward, and a cover member 3Y1 that closes the upper part of the main body frame 3Y2. A storage space for storing toner is formed between the main body frame 3Y2 and the cover member 3Y1. By integrally forming the truncated cone member CyYb of the cyclone CyY with the cover member 3Y1, a configuration in which toner is supplied to the developing container 3Y via the cyclone CyY can be realized with a simple structure having a small number of parts. The truncated cone member CyYb may be formed as a separate member from the cover member 3Y1 and fixed to the cover member 3Y1 by adhesion or other methods.

[0089] In this embodiment, the position of the toner discharge port CyYb2 of the cyclone CyY in the Y direction is located inside the region in the Y direction where the developing roller 6Y is provided (hereinafter referred to as the width region W6 of the developing roller 6; see also Figures 11(a) and 13). The width region W6 of the developing roller 6Y is the range from one end to the other end in the Y direction of the outer circumferential surface of the developing roller 6Y on which the toner is carried. In other words, for each developing unit 9, in the direction of the rotation axis of the developing roller 6 (the rotation axis direction of the developing roller 6), the first discharge port of the cyclone Cy is provided at a position between both ends of the outer circumferential surface (toner carrying portion) of the developing roller 6 in the rotation axis direction. This arrangement can improve the efficiency of toner transport, as described later.

[0090] In this embodiment, the cyclone CyY is disposed on the upper surface of the developing container 3Y (toner storage section). The upper surface of the developing container 3Y is a surface (facing upward in the Z direction) included in the top view of the developing container 3Y. By disposing the cyclone CyY on the upper surface of the developing container 3Y, the cyclone CyY and the internal space of the developing container 3Y overlap when viewed in the Z direction. Therefore, compared with a case in which the cyclone CyY protrudes in the X direction or Y direction relative to the internal space of the developing container 3Y when viewed in the Z direction, the area occupied by the developing unit 9Y when viewed in the Z direction can be reduced, and the device can be made more compact. Note that "two elements overlap when viewed in a specific direction" means that when each element is vertically projected onto a virtual plane perpendicular to the specific direction, the projection area of ​​one element and the projection area of ​​the other element at least partially overlap.

[0091] In addition, in this embodiment, when viewed in the Z direction, the toner discharge port CyYb2 of the cyclone CyY overlaps with the outer peripheral surface 6Ya of the developing roller 6Y (FIG. 13). In other words, in the direction of the rotation axis of the developing roller, the first discharge port is located between both ends of the outer peripheral surface (toner carrying portion) of the developing roller in the direction of the rotation axis, and when viewed in the direction of gravity, the first discharge port of the cyclone and the outer peripheral surface (toner carrying portion) of the developing roller overlap. With this configuration, since the outer peripheral surface 6Ya of the developing roller 6Y is located directly below the toner discharge port CyYb2, it becomes easier to make the toner discharged from the toner discharge port CyYb2 reach the outer peripheral surface 6Ya of the developing roller 6Y. In other words, the efficiency of toner transport can be further improved.

[0092] However, the toner discharge port CyYb2 may be positioned so as not to overlap with the outer peripheral surface 6Ya of the developing roller 6Y when viewed in the direction of gravity. In this case, the toner is transported in the X direction by the stirring members SY1 and SY2 in the developing container 3Y, so that the toner is supplied to the outer peripheral surface 6Ya of the developing roller 6Y. The developing unit 9Y may further include a supply roller that supplies toner to the developing roller 6Y.

[0093] In this embodiment, the truncated cone portion CyYb1 of the cyclone CyY protrudes downward from the inner surface 3Y1a (FIG. 13) of the upper surface (cover member 3Y1) of the developing container 3Y. In other words, the cyclone CyY is disposed on the upper surface of the developing container 3Y (toner storage portion), and a part of the cyclone CyY is embedded below the upper surface of the toner storage portion. In other words, at least a part of the truncated cone portion CyYb1 protrudes downward from the top surface (inner surface 3Y1a) of the developing container 3Y (toner storage portion). This configuration makes it possible to reduce the size of the developing unit 9Y in the Z direction. In other words, the cyclone CyY and the developing container 3Y occupy a lower height in the Z direction than when the entire cyclone CyY is disposed above the upper surface of the developing container 3Y. In this embodiment, the entire truncated cone portion CyYb1 protrudes downward from the inner surface 3Y1a of the lid member 3Y1, but only a part of the truncated cone portion CyYb1 may protrude downward from the inner surface 3Y1a of the lid member 3Y1.

[0094] Although the development unit 9Y can be made smaller by shortening the truncated cone portion CyYb1, the separation performance of the cyclone CyY may be reduced if the truncated cone portion CyYb1 is short. According to the configuration of this embodiment, it is not necessary to shorten the truncated cone portion CyYb1 extremely, so that it is possible to achieve both the separation performance of the cyclone CyY and the miniaturization of the development unit 9Y.

[0095] [Toner transport mechanism] The mechanism by which the toner contained in the toner chamber 430Yc of the cartridge 430Y is transported to the developing unit 9Y will be described.

[0096] As shown in FIG. 5(a), the air discharged upward from the discharge port 80Ya of the pump unit 80Y is received in the air chamber 430Yd through the receiving port 430Yb1 of the cartridge 430Y. Then, the air increases the air pressure in the air chamber 430Yd, passes through the filter 83Y, and flows into the toner chamber 430Yc. The air that flows into the toner chamber 430Yc enters between the particles of the toner T and fluidizes the toner T. The toner T that is mixed with the air and fluidized is moved by the air received in the air chamber 430Yd through the receiving port 430Yb1. The toner is moved by the air through the discharge pipe 85Y from the inlet 85Ya to the outlet 85Yb, and is discharged to the outside of the cartridge 430Y from the discharge port 430Ya1.

[0097] By providing the air chamber 430Yd, which is a highly sealed space, between the discharge port 80Ya and the filter 83Y as in this embodiment, the air discharged from the discharge port 80Ya efficiently travels to the filter 83Y without dispersing outside the cartridge 430Y. For example, assume that the cartridge 430Y is subjected to vibration or left for a long time, causing the toner T in the toner chamber 430Yc to aggregate. In such a situation, the pressure required to pass through the filter 83Y and flow into the toner chamber 430Yc may be high. Even in this case, air can be passed through the filter 83Y and sent into the toner chamber 430Yc by continuing to send air from the pump unit 80Y to the air chamber 430Yd and increasing the pressure (atmospheric pressure) in the air chamber 430Yd. In addition, by providing the air chamber 430Yd, the pump unit 80Y only needs to have the performance to generate a pressure capable of continuing to send air into the air chamber 430Yd until the pressure reaches the pressure required for the air to pass from the filter 83Y into the toner chamber 430Yc. In other words, the pump unit 80Y does not need to have special performance in terms of discharge speed or discharge amount, which makes it possible to employ a small pump unit, which contributes to the miniaturization of the device.

[0098] 5A, the toner T discharged from the discharge port 430Ya1 of the cartridge 430Y passes through the receiving port 429Ya of the cartridge holder 429 and enters the inside of the supply pipe 444Y from the upstream end 444Yu. The toner T that has entered the inside of the supply pipe 444Y from the upstream end 444Yu is moved to the downstream end 444Yd by air that has been discharged from the discharge port 430Ya1 of the cartridge 430Y like the toner T and flowed into the upstream end 444Yu. The toner T that has been moved to the downstream end 444Yd flows into the cyclone CyY from the inlet CyYa1 together with the air.

[0099] The air containing the toner that has flowed into the cyclone CyY descends while swirling around the central axis Ax inside the cylindrical portion CyYa2 and the truncated cone portion CyYb1, as shown in Figures 11(a) and 11(c). During this process, the toner T moves closer to the inner walls of the cylindrical portion CyYa2 and the truncated cone portion CyYb1 due to centrifugal force, and moves along the inner walls. On the other hand, the closer the air containing the toner T approaches the toner discharge port CyYb2, the smaller the cross-sectional area of ​​the truncated cone portion CyYb1 becomes. Therefore, the toner T continues to move along the inner wall of the truncated cone portion CyYb1 due to centrifugal force, while the air, which has a lower specific gravity than the toner T, is pushed toward the center of the cylindrical portion CyYa2 and the truncated cone portion CyYb1. The pushed-out air flows along the central axis Ax toward the exhaust port CyYa3 that leads to the external space of the cyclone CyY. As a result, by the time the air containing the toner T reaches the vicinity of the toner discharge port CyYb2, most of the air reverses and becomes an ascending air current, passing through the exhaust port CyYa3, the chamber part CyYC, and the exhaust filter CyYf and being discharged to the outside of the developing container 3Y. Note that, as will be described later, if the developing container 3Y is not made airtight by providing the exhaust filter part PYf (FIG. 3) in the developing container 3Y, part of the air is discharged from the toner discharge port CyYb2 to the developing container 3Y.

[0100] Meanwhile, the toner T continues to descend under its own weight while rotating near the toner discharge port CyYb2, is discharged from the toner discharge port CyYb2, and is accommodated in the accommodation space in the developing container 3Y. As a result, the toner T is replenished from the cartridge 430Y to the developing unit 9Y of the process unit PY.

[0101] In this way, the toner T is supplied to the developing unit 9Y in a state where most of the air has been separated by the cyclone CyY. In other words, according to this embodiment, the toner can be supplied to the developing container 3Y (toner storage unit) in a state where it is separated from the air. Therefore, the separation performance can be maintained for a long period of time compared to a configuration in which the toner is separated from the air mainly by a filter.

[0102] According to this embodiment, since the toner T is supplied to the developing unit 9Y in a state where most of the air has been separated by the cyclone CyY, it is possible to reduce the rise in the internal pressure of the developing unit 9Y due to the inflow of air. By reducing the rise in the internal pressure of the developing unit 9Y, it is possible to prevent toner leakage from the developing unit 9Y (for example, scattering of the toner T together with the air from the opening of the developing container 3Y in which the developing roller 6Y is disposed). In addition, by reducing the rise in the internal pressure of the developing unit 9Y, the driving load of the pump unit 80Y is less likely to increase. Therefore, for example, it is possible to employ a smaller pump unit 80Y, which contributes to the miniaturization of the device.

[0103] According to this embodiment, air from which most of the toner T has been separated is exhausted from the exhaust port CyYa3, so that the exhaust filter CyYf is less likely to become clogged with toner T, and the durability of the toner transport function from the toner container to the developing container is improved.

[0104] Furthermore, in order to improve the discharge of air out of the developing unit 9, exhaust filter parts PYf, PMf, PCf, PKf (other filters) may be provided on the upper surface of each developing unit 9 in addition to the exhaust filters of each cyclone Cy, as shown in Fig. 3. Hereinafter, the exhaust filter parts PYf, PMf, PCf, PKf will be referred to as each exhaust filter part Pf. Each exhaust filter part Pf has an opening (exhaust hole, through hole) provided on the upper surface of a frame (cover member) that forms the developing unit 9, and a filter such as nonwoven fabric is attached to cover the opening.

[0105] The toner T that has flowed into each developing unit 9 via each cyclone Cy remains in the developing unit 9, and at least a portion of the air that has flowed into the developing unit 9 together with the toner T is discharged to the outside of the developing unit 9 through the exhaust filter portion Pf. This further suppresses an increase in the internal pressure inside each developing unit 9, and makes it easier for the toner T and air to flow from each cartridge 430 into each developing unit 9 via each supply pipe 444. By providing each exhaust filter portion Pf in each developing unit 9, it becomes easier for the toner T (and a portion of the air) to flow into each developing unit 9 via each cyclone Cy.

[0106] In this embodiment, the exhaust filter portion Pf is provided on the upper surface of each developing unit 9 downstream of the cyclone Cy in the toner inflow direction to the cyclone Cy. That is, for the developing units 9Y and 9M, the exhaust filter portions PYf and PMf are provided on the upper surface of the developing units 9Y and 9M on the RE side in the Y direction from the cyclones CyY and CyM, respectively. For the developing units 9C and 9K, the exhaust filter portions PCf and PKf are provided on the upper surface of the developing units 9C and 9K on the LE side in the Y direction from the cyclones CyC and CyK, respectively. In other words, the developing container 3 (toner storage portion) of each developing unit 9 has an opening provided at a position farther away from the intake (inlet) of the cyclone Cy than the exhaust port in the direction of the rotation axis of the developing roller 6, and an exhaust filter covering the opening. With this configuration, it is possible to improve the discharge of air by utilizing the area where there are no supply pipes 444 connected to each cyclone Cy. The exhaust filter portion may be provided on the side surface of each developing unit 9 instead of on the top surface.

[0107] The toner supplied from the end of the developing unit 9Y in the Y direction into the developing unit 9Y (developing container 3Y) is stirred and leveled by the stirring members SY1 and SY2 shown in FIG. 5(b) and FIG. 12. The stirring members SY1 and SY2 may be screws configured to transport the toner from the end of the developing unit 9Y on the side (LE side) to which the downstream end 444Yd of the supply pipe 444Y is connected in the Y direction toward the end of the developing unit 9Y on the opposite side. The stirring members SY1 and SY2 are not limited to screws having a spiral blade formed on a rotating shaft, but may be, for example, paddle-shaped rotating members having a number of short blades or protrusions formed on a rotating shaft. In addition, the number of stirring members may be one or three or more depending on the required stirring efficiency of the toner T in the developing unit 9Y.

[0108] In this embodiment, the toner discharge port CyYb2 of the cyclone CyY is disposed on the upper surface of the developing container 3Y and within the width region W6 of the developing roller 6Y, which is the position where the toner T is used in the Y direction. Therefore, inside the developing container 3Y, the toner T supplied from the toner discharge port CyYb2 can easily reach the developing roller 6Y. More specifically, the distance over which the toner T is transported in the Y direction to spread the toner T throughout the width region W6 of the developing roller 6Y is shorter than in a configuration in which the toner discharge port CyYb2 is disposed outside the width region W6 of the developing roller 6Y in the Y direction. Thus, the toner can be efficiently transported from the cartridge 430Y to the developing roller 6Y.

[0109] In this embodiment, an example is described in which each cyclone Cy is disposed at an end of each developing unit 9 in the Y direction as shown in Fig. 3(a) in consideration of pressure loss, but as a modified example, each cyclone Cy may be disposed approximately at the center of each developing unit 9 in the Y direction as shown in Fig. 12. The center of each developing unit 9 in the Y direction is the intermediate position between the end position on one side and the end position on the other side of each developing container 3 in the Y direction.

[0110] As shown in FIG. 11(a), the toner T descends while rotating inside the cyclone CyY, and flows into the storage space in the developing container 3Y from the toner discharge port CyYb2. The toner T discharged from the toner discharge port CyYb2 has momentum in a direction along the inner wall of the truncated cone portion CyYb1 (a tangent direction to the circumference). Therefore, not all the toner T falls vertically from the toner discharge port CyYb2 in the Z direction, and the toner T disperses in the developing unit 9Y while moving in directions other than the Z direction. This improves the stirring efficiency in the developing unit 9Y. In addition, it becomes easier to spread the toner T over the width region W6 of the developing roller 6Y, and the toner can be transported efficiently.

[0111] Incidentally, when toner T is replenished into the developing container 3Y through the cyclone CyY, it is possible that the toner T in the developing container 3Y is stirred up and flows back into the cyclone CyY. That is, when the flow of toner T discharged from the toner discharge port CyYb2 hits the toner T accumulated in the developing container 3Y, some of the toner may fly upward and flow into the cyclone CyY from the toner discharge port CyYb2. Therefore, the preferable positions of each part of the cyclone CyY in the Z direction will be described with reference to FIG. 13. FIG. 13 is a cross-sectional view taken along CC in FIG. 4(b).

[0112] As shown in FIG. 13, when the developer level of the toner T in the developing container 3Y (hereinafter referred to as the toner upper surface Ts) is high, the toner T is raised and reaches the cylindrical portion CyYa2 during toner supply. In other words, the toner T in the developing container 3Y flows back into the cyclone CyY, and the toner is raised above the lower end position TL2 of the cylindrical portion CyYa2. In this case, the raised toner T may flow into the exhaust port CyYa3, thereby reducing the separation performance of the cyclone CyY. In addition, the toner T that has flowed into the exhaust port CyYa3 may reduce the clogging prevention effect of the exhaust filter CyYf.

[0113] Therefore, it is preferable that the lower end position TL2 of the cylindrical portion CyYa2 in the Z direction (gravity direction) is above the toner upper surface Ts. Specifically, it is preferable that the lower end position TL2 of the cylindrical portion CyYa2 is above the uppermost portion (the uppermost portion of the toner carrying portion) of the outer circumferential surface 6Ya of the developing roller 6Y. It is preferable that the lower end position TL2 of the cylindrical portion CyYa2 is above the stirring members SY1 and SY2 (above the upper end positions of the stirring members. When there are multiple stirring members, above the one located higher). This can reduce the possibility that the toner T stirred up during toner supply will flow into the exhaust port CyYa3.

[0114] Preferably, the position TL1 of the toner discharge port CyYb2 in the Z direction (gravity direction) is located above the toner upper surface Ts. Specifically, in the gravity direction, the position TL1 of the toner discharge port CyYb2 is preferably located above the top of the outer circumferential surface 6Ya of the developing roller 6Y. The position TL1 of the toner discharge port CyYb2 is preferably located above the stirring members SY1 and SY2. In other words, in the gravity direction, the first discharge port is preferably located above the top of the toner carrying portion of the developing roller. This can reduce the possibility that the toner T stirred up during toner supply will flow into the exhaust port CyYa3.

[0115] Also, it is preferable that the position TL1 of the toner discharge port CyYb2 in the Z direction (gravity direction) is above the rotation axis of the stirring members SY1 and SY2 (if there are multiple stirring members, it is above the rotation axis of the stirring member located higher). In other words, when the rotation axis of the development roller 6Y is the first rotation axis, the image forming apparatus further includes a stirring member that rotates about the second rotation axis so as to stir the toner contained in the toner containing section. In addition, in the gravity direction, the first discharge port is disposed above the second rotation axis of the stirring member. The second rotation axis in this embodiment is the rotation axis of the stirring member SY1. This can reduce the possibility that the toner T stirred up during toner supply will flow into the exhaust port CyYa3.

[0116] In this embodiment, the rotation axis (second rotation axis) of the stirring member SY1 is located above the rotation axis (first rotation axis) of the developing roller 6Y.

[0117] It is preferable to use air as a conveying means for conveying toner when the direction of the conveying path changes midway, as in the case of each supply pipe 444 of this embodiment, or when the toner conveying path differs between multiple process units P or multiple developing units 9. This provides greater freedom in designing the conveying path than using a screw or the like as a conveying means, and reduces the number of parts because no conveying member is required.

[0118] Each supply pipe 444 is an example of a flow path forming portion that is connected to the discharge port of each cartridge 430 (toner container) and the inlet of each cyclone Cy, and forms a flow path for the mixture. In this embodiment, the entire flow path from the discharge port of each cartridge 430 (toner container) to the inlet of each cyclone Cy is formed by each supply pipe 444 as a cylindrical member, but only a part of the flow path may be formed by each supply pipe 444.

[0119] In this embodiment, as shown in Fig. 4(b) and Fig. 11(a), it is preferable that the inlet of each cyclone Cy faces the rotation axis direction (Y direction) of the developing roller 6 of the corresponding developing unit 9. In this embodiment, since the rotation axis direction of each developing roller 6 is substantially the Y direction, it is preferable that the inlet of each cyclone Cy faces the LE side or the RE side in the Y direction. In other words, it is preferable that the intake of the cyclone separator opens in the direction from the center to the end of the corresponding developing roller in the direction of the rotation axis of the developing roller. This allows, for example, the downstream end 444Yd of the supply pipe 444Y to be connected to the inlet CyYa1 without being tightly bent.

[0120] Each of the supply pipes 444 has a bent shape so that the toner transport path from each cartridge 430 to each developing unit 9 does not block the optical path L from the laser scanner unit LB to each photosensitive drum 4. That is, each of the supply pipes 444 has intermediate portions 444Yi, 444Mi, 444Ci, 444Ki (first portions) that pass outside the optical path L and extend in a direction intersecting the rotational axis direction (Y direction) of the developing roller 6. In this embodiment, the intermediate portions 444Yi, 444Mi, 444Ci, 444Ki extend along the X direction. Each of the supply pipes 444 also has a downstream end portion (second portion) that is bent with respect to the intermediate portions 444Yi, 444Mi, 444Ci, 444Ki so as to face the direction along the rotational axis direction (Y direction) of the developing roller 6 and is connected to the inlet of each of the cyclones Cy. The downstream end of each supply pipe 444 is the aforementioned downstream end 444Yd, 444Md, 444Cd, 444Kd. For this reason, as described above, it is preferable that the inlet of each cyclone Cy faces the LE side or the RE side in the Y direction.

[0121] In this embodiment, the inlet of each cyclone Cy is disposed on the side farther from each cartridge 430 in the X direction (the direction in which each process unit P is arranged). For example, as shown in FIG. 11(c), the inlet CyYa1 of the cyclone CyY is disposed on the upper side in the drawing (farther from the cartridge 430Y located at the lower side in the drawing) than the central axis Ax of the cyclone CyY in the X direction. With this configuration, the radius of curvature of the bent portion between the middle portion and the downstream end of each supply pipe 444 can be increased without blocking the optical path L, and the assembly work of each supply pipe 444 becomes easy. In addition, when toner is supplied, the toner is subjected to centrifugal force at the bent portion between the middle portion and the downstream end, and the toner is biased to the outside of each supply pipe 444 at the bent portion. As shown in FIG. 11(c) when viewed in the Z direction, the outer wall surface of each supply pipe 444 at the bent portion is a surface that continues to the inner surface of the cylindrical portion of each cyclone Cy. Therefore, the mixture is introduced into each cyclone Cy with the toner concentrated toward the inner surface of the cylindrical portion, thereby making it possible to further improve the separation efficiency.

[0122] The configurations relating to the cyclone CyY and the developing unit 9Y described above can also be applied to the cyclones CyM, CyC, and CyK provided in the other developing units 9M, 9C, and 9K, respectively.

[0123] Second Embodiment In the above-described first embodiment, a configuration in which the toner T is supplied from each supply pipe 444 through each cyclone Cy to the storage space in each developing container 3 is exemplified. As a second embodiment, a flow path for the mixed gas may be provided in each developing container 3 in addition to the storage space for the toner T. In this embodiment, the mixed gas containing the toner T flows from each supply pipe 444 into the flow path in each developing container 3, and the toner T is supplied from the flow path through the cyclone CyY to the storage space. This embodiment will be described with reference to FIG. 14 to FIG. 16(b). Hereinafter, elements with the same reference symbols as those in the first embodiment have substantially the same configurations and functions as those described in the first embodiment unless otherwise specified, and parts different from the first embodiment will be mainly described.

[0124] Fig. 14 is a perspective view of the image forming unit 500 with each cartridge 430 attached. Fig. 14 also illustrates each optical path L (LY, LM, LC, LK) of the laser light from the laser scanner unit LB toward each photosensitive drum 4. Fig. 15 is a top view of the image forming unit 500. Fig. 16(a) is a sectional view showing the CC section of Fig. 15. Fig. 16(b) is a view showing a state in Fig. 16(a) where the cylindrical member CyYa of the cyclone CyY is removed from the truncated cone member CyYb and the lid member 3Y1 of the developing container 3.

[0125] As shown in FIG. 15, the downstream end 444Yd of the supply pipe 444Y is connected to a flow path 445Y provided in the developing container 3Y. As shown in FIG. 16(a) and (b), the flow path 445Y is formed by a flow path inlet 3Ya1 and a flow path wall surface 3Ya2 integrally formed with the cover member 3Y1 of the developing container 3Y, and a flow path upper surface CyYa4 integrally formed with the cylindrical member CyYa of the cyclone CyY. The flow path inlet 3Ya1 is located at the end of the developing container 3Y in the Y direction (the end of the developing unit 9Y). The cyclone CyY is located approximately at the center of the developing container 3Y in the Y direction (approximately at the center of the developing unit 9Y). The flow path 445Y extends in the Y direction from the flow path inlet 3Ya1 through a transport space formed between the flow path wall surface 3Ya2 and the flow path upper surface CyYa4 to the inlet CyYa1 of the cyclone CyY. The transport space in the flow path 445Y is provided in the upper part of the developing container 3Y, and is separated from the toner Y storage space in the developing container 3Y by a flow path wall surface 3Ya2 and a cyclone CyY.

[0126] The flow inlet 3Ya1, the flow wall surface 3Ya2, and the flow upper surface CyYa4 are an example of a flow path forming part that forms a flow path 445Y that is connected to the inlet CyYa1 of the cyclone CyY and through which the mixed gas flows and is separated from the internal space of the developing container 3Y (toner storage part). The flow path forming part is fixed to the developing container 3Y (toner storage part). Also, as in this embodiment, it is preferable that at least a part of the flow path forming part is integrally formed with the developing container 3Y (toner storage part).

[0127] The toner T transported to the downstream end 444Yd of the supply pipe 444Y flows into the flow passage 445Y from a flow passage inlet 3Ya1 at the end of the developing container 3Y in the Y direction, and flows through the flow passage 445Y into the inlet CyYa1 of the cyclone CyY. Thus, in this embodiment, the transport path of the toner T from the end of the developing container 3Y in the Y direction to the cyclone CyY at approximately the center of the developing container 3Y is formed by the flow passage 445Y fixed to the upper part of the developing container 3Y.

[0128] It is desirable to regulate the position of the supply pipe 444Y in the X direction so as not to block the light path LY. If a structure for regulating the position of each supply pipe 444 in the X direction is added so that each supply pipe 444 does not block each light path L, the device will become more complicated and larger. In this embodiment, the transport path for the toner T is formed by the flow path 445Y fixed to the upper part of the developing container 3Y, so that each supply pipe 444 can be prevented from blocking each light path L without using an additional structure.

[0129] Other Embodiments In each of the above-described embodiments, the exhaust filter CyYf is provided at the exhaust port CyYa3 of the cyclone CyY. However, if the separation performance of the cyclone CyY is high, the exhaust filter CyYf may be omitted.

[0130] In each of the above-described embodiments, a configuration has been shown in which each pump unit 80 provided in the apparatus body 72 of the image forming apparatus 1 discharges air, thereby supplying a mixture containing air from each pump unit 80 and toner from each cartridge 430 to each cyclone Cy. However, as long as a mixture containing air and replenishment toner is supplied to each cyclone Cy, the configurations related to each cyclone Cy described in each embodiment can be applied.

[0131] For example, in each embodiment, the pump units 80 and the cartridges 430 are in a series relationship (air discharged from a certain pump unit 80 passes through the inside of the corresponding cartridge 430 and the air-fuel mixture is discharged). However, this is not limiting, and each pump unit 80 and each cartridge 430 (toner container) may be in a parallel relationship. In other words, a configuration may be adopted in which a flow path of air discharged from a certain pump unit 80 and a flow path of toner discharged from the corresponding cartridge 430 merge, and the air-fuel mixture flows from the merged portion to the corresponding cyclone Cy. In this case, a discharge unit (powder pump) that discharges toner from each cartridge 430 (toner container) may be provided to transport the toner to the merged portion.

[0132] Each pump unit 80 is an example of an air supply unit that supplies air for replenishing toner to the corresponding developing unit. The air supply unit is not limited to a pump, and may be, for example, a fan.

[0133] Also, the means for generating the air flow for transporting the toner may be a part of the toner container. For example, a bellows-shaped volumetric pump may be disposed at the end of a cylindrical toner bottle, and the volumetric pump may expand and contract as the toner bottle rotates, thereby discharging a mixture of air and toner from the toner bottle.

[0134] Furthermore, the image forming apparatus 1 may be configured to supply toner to each developing container 3 using a toner container from outside the image forming apparatus 1. For example, the toner container is attached to a mounting portion provided on the image forming apparatus 1, and a user operates the toner container to discharge a mixture containing air and toner from the toner container. The toner container may be a bag-shaped container (pouch container) in which air is enclosed together with the toner, or a cylindrical container in which air is enclosed together with the toner.

[0135] In each of the above-described embodiments, each developing unit 9 may be a cartridge (developing cartridge) configured to be detachable from the apparatus main body 72. In addition, each process unit P including each developing unit 9 may be a cartridge (process cartridge) configured to be detachable from the apparatus main body 72.

[0136] Summary of the Disclosure The present disclosure includes at least the following configurations.

[0137] (Configuration 1) An image forming apparatus, A photosensitive drum; a toner storage unit for storing toner, the toner storage unit being configured so that toner is replenished using air; a developing roller that rotates about a rotation axis, the developing roller having a toner carrying portion that carries the toner contained in the toner storage portion, and that supplies the toner carried on the toner carrying portion to the photosensitive drum; a cyclone separator having an intake port, a first discharge port leading to the inside of the toner storage unit, and a second discharge port leading to the outside of the toner storage unit, configured to take in air mixed with toner from the intake port, separate the toner and the air, and discharge the separated toner and air from the first discharge port and the second discharge port, respectively; Equipped with the first discharge port is provided at a position between both ends of the toner carrying unit in the direction of the rotation axis, 1. An image forming apparatus comprising:

[0138] (Configuration 2) The cyclone separator is provided on an upper surface of the toner storage unit. 2. The image forming apparatus according to claim 1,

[0139] (Configuration 3) the first discharge port is located below a top surface of the inside of the toner storage unit, The second discharge port is located above an upper surface of the toner storage unit. 3. The image forming apparatus according to claim 1, wherein the first and second components are arranged in a same plane.

[0140] (Configuration 4) The first exhaust port opens downward, The second outlet is open upward. 4. The image forming apparatus according to claim 3,

[0141] (Configuration 5) The first exhaust port opens downward, The second outlet is open upward. 3. The image forming apparatus according to claim 1, wherein the first and second components are arranged in a same plane.

[0142] (Configuration 6) the inlet is open in a direction from a center portion of the developing roller toward an end portion thereof in a direction of the rotation axis of the developing roller; 6. The image forming apparatus according to any one of configurations 1 to 5.

[0143] (Configuration 7) The cyclone separator has: a cylindrical portion in which the inlet is provided, the cylindrical portion having a central axis extending along the direction of gravity; a truncated cone portion that is continuous with a lower end of the cylindrical portion below the cylindrical portion and is formed into a truncated cone shape with a radius that decreases downward; and a tubular portion that extends downward from the second discharge outlet along the direction of the central axis of the truncated cone portion, the tubular portion being provided at a position that overlaps with the inlet when viewed in a direction perpendicular to the central axis, A lower end of the tubular portion is open to an internal space of the cyclone separator formed by the cylindrical portion and the truncated cone portion. 7. The image forming apparatus according to any one of configurations 3 to 6.

[0144] (Configuration 8) the cyclone separator has a cylindrical portion in which the inlet is provided, the cylindrical portion having a central axis extending along a direction of gravity, and a truncated cone portion that is continuous with a lower end of the cylindrical portion below the cylindrical portion and has a truncated cone shape with a radius that decreases downward, The first outlet is provided at a lower end of the truncated cone portion, The second outlet is provided at an upper end of the cylindrical portion, the first discharge port is disposed above the uppermost portion of the toner carrying portion of the developing roller in a gravity direction. 7. The image forming apparatus according to any one of configurations 2 to 6.

[0145] (Configuration 9) In the case where the rotation axis is a first rotation axis, a stirring member that rotates about a second rotation axis so as to stir the toner contained in the toner container, In a gravity direction, the first discharge port is disposed above the second rotation axis of the stirring member. 9. The image forming apparatus according to any one of configurations 2 to 8.

[0146] (Configuration 10) In the direction of gravity, the second rotation axis is disposed above the first rotation axis. 10. The image forming apparatus according to claim 9,

[0147] (Configuration 11) When viewed in the gravity direction, the first discharge port and the toner carrying portion of the developing roller overlap each other. 11. The image forming apparatus according to any one of configurations 2 to 10.

[0148] (Configuration 12) The cyclone separator has a truncated cone portion formed in a truncated cone shape whose radius decreases toward the bottom, The first outlet is provided at a lower end of the truncated cone portion, At least a portion of the truncated cone portion protrudes downward from a top surface of the interior of the toner storage portion. 12. The image forming apparatus according to any one of configurations 2 to 11.

[0149] (Configuration 13) the truncated cone portion of the cyclone separator is integrally formed with the upper surface portion of the toner storage portion, 13. The image forming apparatus according to claim 12,

[0150] (Configuration 14) An image forming apparatus, A photosensitive drum; a toner storage unit for storing toner, the toner storage unit being configured so that toner is replenished using air; a developing roller that rotates about a rotation axis, the developing roller having a toner carrying portion that carries the toner contained in the toner storage portion, and that supplies the toner carried on the toner carrying portion to the photosensitive drum; a cyclone separator having an intake port, a first discharge port leading to the inside of the toner storage unit, and a second discharge port leading to the outside of the toner storage unit, configured to take in air mixed with toner from the intake port, separate the toner and the air, and discharge the separated toner and air from the first discharge port and the second discharge port, respectively; Equipped with the cyclone separator is provided on an upper surface of the toner storage unit, The cyclone separator has a truncated cone portion formed in a truncated cone shape whose radius decreases toward the bottom, The first outlet is provided at a lower end of the truncated cone portion, At least a portion of the truncated cone portion protrudes downward from a top surface of the interior of the toner storage portion. 1. An image forming apparatus comprising:

[0151] (Configuration 15) the first discharge port is disposed above the uppermost portion of the toner carrying portion of the developing roller in a gravity direction. 15. The image forming apparatus according to claim 14,

[0152] (Configuration 16) When viewed in the gravity direction, the first discharge port and the toner carrying portion of the developing roller overlap each other. 16. The image forming apparatus according to claim 14 or 15.

[0153] (Configuration 17) the truncated cone portion of the cyclone separator is integrally formed with the upper surface portion of the toner storage portion, 17. The image forming apparatus according to any one of configurations 14 to 16.

[0154] (Configuration 18) the cyclone separator further includes a filter provided to cover the second discharge port, the filter allowing air to pass through but preventing toner from passing through; 18. The image forming apparatus according to any one of configurations 1 to 17.

[0155] (Configuration 19) the second discharge port is provided at a second end of a cylindrical portion opposite to the first end, the first end of which opens into an internal space of the cyclone separator; the cyclone separator has a chamber portion that forms a space between the second outlet and the filter, A cross-sectional area of ​​the space formed by the chamber portion perpendicular to the extension direction of the cylindrical portion is larger than a cross-sectional area of ​​the space perpendicular to the extension direction of the cylindrical portion. 19. The image forming apparatus according to configuration 18,

[0156] (Configuration 20) an air supply unit that supplies air; a toner container for storing toner to be replenished to the toner storage unit, the toner container having an inlet for receiving air supplied from the air supply unit and an outlet for discharging the toner stored in the toner container together with the air from the air supply unit; Further comprising: 20. The image forming apparatus according to any one of configurations 1 to 19.

[0157] (Configuration 21) a pipe connected to the discharge port of the toner container and the intake port of the cyclone separator, through which air mixed with toner passes; 21. The image forming apparatus according to configuration 20.

[0158] (Configuration 22) an exposure device that exposes the photosensitive drum to light to form a latent image; the inlet is open in a direction from a center portion of the developing roller toward an end portion of the developing roller in a direction of the rotation axis of the developing roller, the pipe has a first portion extending in a direction intersecting the rotation axis on the outer side of an optical path from the exposure device toward the photosensitive drum in the direction of the rotation axis, and a second portion communicating with the first portion, extending in a direction along the rotation axis, and connected to the intake port. 22. The image forming apparatus according to claim 21,

[0159] (Configuration 23) a pipe connected at one end to the outlet of the toner container and through which air mixed with toner passes; a flow path forming portion that is connected to the other end of the pipe and the inlet of the cyclone separator, and that forms a flow path through which air mixed with toner flows, the flow path being separated from an internal space of the toner storage portion, the flow path forming portion is fixed to the toner storage portion; 21. The image forming apparatus according to configuration 20.

[0160] (Configuration 24) the toner storage section has an opening provided at a position farther from the intake port than the second discharge port in the direction of the rotation axis of the developing roller, and a filter covering the opening, the filter allowing air to pass through and preventing toner from passing through. 24. The image forming apparatus according to any one of configurations 1 to 23.

[0161] (Configuration 25) A developing unit for use in an image forming apparatus, comprising: a toner storage unit for storing toner, the toner storage unit being configured so that toner is replenished using air; a developing roller that rotates about a rotation axis, the developing roller having a toner carrying portion that carries the toner contained in the toner storage portion, and for supplying the toner carried on the toner carrying portion to a photosensitive drum; a cyclone separator having an intake port, a first discharge port leading to the inside of the toner storage unit, and a second discharge port leading to the outside of the toner storage unit, configured to take in air mixed with toner from the intake port, separate the toner and the air, and discharge the separated toner and air from the first discharge port and the second discharge port, respectively; Equipped with The first discharge port is provided at a position between both ends of the toner carrying portion in the direction of the rotation axis. A developing unit characterized by:

[0162] (Configuration 26) In the posture of the developing unit when the developing unit is attached to the main body of the image forming apparatus, the cyclone separator is provided on an upper surface of the toner storage unit, The cyclone separator has a truncated cone portion formed in a truncated cone shape whose radius decreases toward the bottom, The first outlet is provided at a lower end of the truncated cone portion, At least a portion of the truncated cone portion protrudes downward from a top surface of the interior of the toner storage portion. 26. The developing unit according to claim 25, [Explanation of symbols]

[0163] 3Y, 3M, 3C, 3K... toner storage section (developing container) / 4Y, 4M, 4C, 4K... photosensitive drum / 6Y, 6M, 6C, 6K... developing roller / 6Ya... toner carrier / CyY, CyM, CyC, CyK... cyclone separator (cyclone) / CyYa1... intake port (inlet) / CyYa3... second outlet (exhaust port) / CyYb2... first outlet (toner outlet)

Claims

1. An image forming apparatus, A photosensitive drum; a toner storage unit for storing toner, the toner storage unit being configured so that toner is replenished using air; a developing roller that rotates about a rotation axis, the developing roller having a toner carrying portion that carries the toner contained in the toner storage portion, and that supplies the toner carried on the toner carrying portion to the photosensitive drum; a cyclone separator provided with an intake port, a first discharge port leading to the inside of the toner storage unit, and a second discharge port leading to the outside of the toner storage unit, configured to take in air mixed with toner from the intake port, separate the toner and the air, and discharge the separated toner and air from the first discharge port and the second discharge port, respectively; Equipped with the first discharge port is provided at a position between both ends of the toner carrying portion in the direction of the rotation axis, 1. An image forming apparatus comprising:

2. The cyclone separator is provided on an upper surface of the toner storage unit.

2. The image forming apparatus according to claim 1,

3. the first discharge port is located below a top surface of the inside of the toner storage unit, the second discharge port is located above an upper surface of the toner storage unit; 3. The image forming apparatus according to claim 2,

4. The first exhaust port opens downward, The second outlet is open upward.

4. The image forming apparatus according to claim 3.

5. The first exhaust port opens downward, The second outlet is open upward.

2. The image forming apparatus according to claim 1,

6. the inlet is open in a direction from a center portion of the developing roller toward an end portion thereof in a direction of the rotation axis of the developing roller; 6. The image forming apparatus according to claim 5,

7. The cyclone separator has: a cylindrical portion in which the inlet is provided, the cylindrical portion having a central axis extending along the direction of gravity; a truncated cone portion that is continuous with a lower end of the cylindrical portion below the cylindrical portion and is formed into a truncated cone shape with a radius that decreases downward; and a tubular portion that extends downward from the second discharge outlet along the direction of the central axis of the truncated cone portion, the tubular portion being provided at a position that overlaps with the inlet when viewed in a direction perpendicular to the central axis, A lower end of the tubular portion is open to an internal space of the cyclone separator formed by the cylindrical portion and the truncated cone portion.

4. The image forming apparatus according to claim 3.

8. the cyclone separator has a cylindrical portion in which the inlet is provided, the cylindrical portion having a central axis extending along a direction of gravity, and a truncated cone portion that is continuous with a lower end of the cylindrical portion below the cylindrical portion and has a truncated cone shape with a radius that decreases downward, The first outlet is provided at a lower end of the truncated cone portion, The second outlet is provided at an upper end of the cylindrical portion, the first discharge port is disposed above an uppermost portion of the toner carrying portion of the developing roller in a gravity direction; 3. The image forming apparatus according to claim 2,

9. In the case where the rotation axis is a first rotation axis, a stirring member that rotates about a second rotation axis so as to stir the toner contained in the toner container, In a gravity direction, the first discharge port is disposed above the second rotation axis of the stirring member.

3. The image forming apparatus according to claim 2,

10. In the direction of gravity, the second rotation axis is disposed above the first rotation axis.

10. The image forming apparatus according to claim 9,

11. the first discharge port and the toner carrying portion of the developing roller overlap each other when viewed in the gravity direction; 3. The image forming apparatus according to claim 2,

12. The cyclone separator has a truncated cone portion formed in a truncated cone shape whose radius decreases toward the bottom, The first outlet is provided at a lower end of the truncated cone portion, At least a portion of the truncated cone portion protrudes downward from a top surface of the interior of the toner storage portion.

3. The image forming apparatus according to claim 2,

13. the truncated cone portion of the cyclone separator is integrally formed with the upper surface portion of the toner storage portion, 13. The image forming apparatus according to claim 12.

14. An image forming apparatus, A photosensitive drum; a toner storage unit for storing toner, the toner storage unit being configured so that toner is replenished using air; a developing roller that rotates about a rotation axis, the developing roller having a toner carrying portion that carries the toner contained in the toner storage portion, and that supplies the toner carried on the toner carrying portion to the photosensitive drum; a cyclone separator provided with an intake port, a first discharge port leading to the inside of the toner storage unit, and a second discharge port leading to the outside of the toner storage unit, configured to take in air mixed with toner from the intake port, separate the toner and the air, and discharge the separated toner and air from the first discharge port and the second discharge port, respectively; Equipped with the cyclone separator is provided on an upper surface of the toner storage unit, The cyclone separator has a truncated cone portion formed in a truncated cone shape whose radius decreases toward the bottom, The first outlet is provided at a lower end of the truncated cone portion, At least a portion of the truncated cone portion protrudes downward from a top surface of the interior of the toner storage portion.

1. An image forming apparatus comprising:

15. the first discharge port is disposed above an uppermost portion of the toner carrying portion of the developing roller in a gravity direction; 15. The image forming apparatus according to claim 14.

16. the first discharge port and the toner carrying portion of the developing roller overlap each other when viewed in the gravity direction; 15. The image forming apparatus according to claim 14.

17. the truncated cone portion of the cyclone separator is integrally formed with the upper surface portion of the toner storage portion, 15. The image forming apparatus according to claim 14.

18. the cyclone separator further includes a filter provided to cover the second discharge port, the filter allowing air to pass through but preventing toner from passing through; 18. The image forming apparatus according to claim 1,

19. the second discharge port is provided at a second end of a cylindrical portion opposite to the first end, the first end of which opens into an internal space of the cyclone separator; the cyclone separator has a chamber portion that forms a space between the second discharge port and the filter, A cross-sectional area of ​​the space formed by the chamber portion perpendicular to the extension direction of the cylindrical portion is larger than a cross-sectional area of ​​the space perpendicular to the extension direction of the cylindrical portion.

20. The image forming apparatus according to claim 18,

20. an air supply unit that supplies air; a toner container for storing toner to be replenished to the toner storage unit, the toner container having an inlet for receiving air supplied from the air supply unit and an outlet for discharging the toner stored in the toner container together with the air from the air supply unit; Further comprising:

18. The image forming apparatus according to claim 1,

21. a pipe connected to the discharge port of the toner container and the intake port of the cyclone separator, through which air mixed with toner passes; 21. The image forming apparatus according to claim 20.

22. an exposure device that exposes the photosensitive drum to light to form a latent image; the inlet is open in a direction from a center portion of the developing roller toward an end portion of the developing roller in a direction of the rotation axis of the developing roller, the pipe has a first portion extending in a direction intersecting the rotation axis on the outer side of an optical path from the exposure device toward the photosensitive drum in the direction of the rotation axis, and a second portion communicating with the first portion, extending in a direction along the rotation axis, and connected to the intake port.

22. The image forming apparatus according to claim 21.

23. a pipe connected at one end to the outlet of the toner container and through which air mixed with toner passes; a flow path forming portion that is connected to the other end of the pipe and the inlet of the cyclone separator, and that forms a flow path through which air mixed with toner flows, the flow path being separated from an internal space of the toner storage portion, the flow path forming portion is fixed to the toner storage portion; 21. The image forming apparatus according to claim 20.

24. the toner storage section has an opening provided at a position farther from the intake port than the second discharge port in the direction of the rotation axis of the developing roller, and a filter covering the opening, the filter allowing air to pass through and preventing toner from passing through, 18. The image forming apparatus according to claim 1,

25. A developing unit for use in an image forming apparatus, comprising: a toner storage unit for storing toner, the toner storage unit being configured so that toner is replenished using air; a developing roller that rotates about a rotation axis, the developing roller having a toner carrying portion that carries the toner contained in the toner storage portion, and for supplying the toner carried on the toner carrying portion to a photosensitive drum; a cyclone separator provided with an intake port, a first discharge port leading to the inside of the toner storage unit, and a second discharge port leading to the outside of the toner storage unit, configured to take in air mixed with toner from the intake port, separate the toner and the air, and discharge the separated toner and air from the first discharge port and the second discharge port, respectively; Equipped with The first discharge port is provided at a position between both ends of the toner carrying portion in the direction of the rotation axis. A developing unit characterized by:

26. In the posture of the developing unit when the developing unit is attached to the main body of the image forming apparatus, the cyclone separator is provided on an upper surface of the toner storage unit, The cyclone separator has a truncated cone portion formed in a truncated cone shape whose radius decreases toward the bottom, The first outlet is provided at a lower end of the truncated cone portion, At least a portion of the truncated cone portion protrudes downward from a top surface of the interior of the toner storage portion.

26. The developer unit of claim 25.

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