Image forming apparatus

Abstract

This invention provides a form of image forming apparatus that transports toner along with air. [Solution] The image forming apparatus comprises a first cartridge, a second cartridge, and a main body to which the first and second cartridges can be attached and detached. The main body comprises a pump unit, a first developing container, a second developing container, a first tube, and a second tube. The portion of the first tube that is longer than half the length from the first end to the second end, and the portion of the second tube that is longer than half the length from the third end to the fourth end, are provided to extend in a horizontal direction, a downward sloping direction, or an upward sloping direction of 45 degrees or less with respect to the horizontal direction. The length of the first tube from the first end to the second end is longer than the length of the second tube from the third end to the fourth end, and the cross-sectional area of ​​the internal space of the first tube is wider than the cross-sectional area of ​​the internal space of the second tube.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus that conveys toner together with air.

Background Art

[0002] Generally, an electrophotographic image forming apparatus forms an image by transferring a toner image formed on the surface of a photosensitive drum onto a transfer material as a transfer medium. And, as a developer replenishment method, for example, a process cartridge method and a toner replenishment method are known. The process cartridge method is a method in which a photosensitive drum and a developing container are integrated as a process cartridge, and when the developer runs out, the process cartridge is replaced with a new one.

[0003] On the other hand, the toner replenishment method is a method of newly replenishing toner into a developing container when the toner runs out. Conventionally, an image forming apparatus has been proposed that has a powder storage unit for storing toner and includes a powder supply apparatus capable of supplying toner to a toner hopper provided in the image forming apparatus main body (see Patent Document 1). The powder supply apparatus has an air pump that discharges air into the powder storage unit and a suction pump that sucks the toner stored in the powder storage unit toward the toner hopper.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a form of an image forming apparatus that conveys toner together with air.

Means for Solving the Problems

[0006] One aspect of the present invention is an image forming apparatus comprising: a first cartridge for containing a first toner; a second cartridge for containing a second toner; an apparatus body to which the first cartridge and the second cartridge can be attached and detached, comprising: a pump unit for discharging air; a first developing container including a first toner storage section for containing the first toner; a second developing container including a second toner storage section for containing the second toner; a first end communicating with the interior of the first cartridge; and a second end communicating with the interior of the first toner storage section, extending from the first end to the second end and the first The device body comprises a first tube through which toner passes, a third end communicating with the inside of the second cartridge, and a fourth end communicating with the inside of the first toner storage section, the second tube extending from the third end to the fourth end and through which the second toner passes, and the first cartridge comprises a first toner chamber for storing the first toner, a first filter configured to obstruct the passage of the first toner but allow the passage of air, and a first air chamber adjacent to the first toner chamber via the first filter, through which air discharged from the pump section is discharged. The first cartridge has a first air chamber provided with a first intake for taking in air, a first outlet for discharging the first toner contained in the first toner chamber to the outside of the first cartridge, and a first pipe configured to communicate with the first outlet, through which the first toner discharged from the first outlet passes. The second cartridge has a second toner chamber for containing the second toner, a second filter configured to obstruct the passage of the second toner but allow the passage of air, and a second air chamber adjacent to the second toner chamber via the second filter, the The first cartridge has a second air chamber with a second intake port for taking in air discharged from the pump section, a second outlet for discharging the second toner contained in the second toner chamber to the outside of the second cartridge, and a second pipe configured to communicate with the second outlet, through which the second toner discharged from the second outlet passes, and is configured such that the first toner in the first toner chamber is discharged from the first outlet and transported to the first toner storage section via the first tube by air taken in from the first intake port of the first cartridge.The image forming apparatus is configured such that air taken in from the second intake of the second cartridge causes the second toner in the second toner chamber to be discharged from the second outlet and transported to the second toner storage section via the second tube; the portion of the first tube longer than half the length from the first end to the second end extends horizontally, downwards, or upwards at an angle of 45 degrees or less relative to the horizontal direction in the direction in which the first toner is transported; the portion of the second tube longer than half the length from the third end to the fourth end extends horizontally, downwards, or upwards at an angle of 45 degrees or less relative to the horizontal direction in the direction in which the second toner is transported; the length of the first tube from the first end to the second end is longer than the length of the second tube from the third end to the fourth end; and the cross-sectional area of ​​the internal space of the first tube is wider than the cross-sectional area of ​​the internal space of the second tube.

[0007] Another aspect of the present invention is an image forming apparatus comprising: a first cartridge for containing a first toner; a second cartridge for containing a second toner; an apparatus body to which the first cartridge and the second cartridge can be attached and detached, comprising: a pump unit for discharging air; a first developing container including a first toner storage section for containing the first toner; a second developing container including a second toner storage section for containing the second toner; a first end communicating with the interior of the first cartridge; and a second end communicating with the interior of the first toner storage section, extending from the first end to the second end and the The device body comprises a first tube through which the first toner passes, a third end communicating with the inside of the second cartridge, and a fourth end communicating with the inside of the first toner storage section, the second tube extending from the third end to the fourth end and through which the second toner passes, the first cartridge comprising a first toner chamber for storing the first toner, a first filter configured to obstruct the passage of the first toner but allow the passage of air, and a first air chamber adjacent to the first toner chamber via the first filter, through which the pump section discharges The first cartridge has a first air chamber provided with a first air intake, a first outlet for discharging the first toner contained in the first toner chamber to the outside of the first cartridge, and a first pipe configured to communicate with the first outlet, through which the first toner discharged from the first outlet passes. The second cartridge has a second toner chamber for containing the second toner, a second filter configured to obstruct the passage of the second toner but allow the passage of air, and a second air chamber adjacent to the second toner chamber via the second filter. The first cartridge has a second air chamber with a second intake port for taking in air discharged from the pump section, a second outlet for discharging the second toner contained in the second toner chamber to the outside of the second cartridge, and a second pipe configured to communicate with the second outlet, through which the second toner discharged from the second outlet passes, and is configured such that the first toner in the first toner chamber is discharged from the first outlet and transported to the first toner storage section via the first tube by air taken in from the first intake port of the first cartridge.The image forming apparatus is configured such that air taken in from the second intake of the second cartridge causes the second toner in the second toner chamber to be discharged from the second outlet and transported to the second toner storage section via the second tube; the portion of the first tube longer than half the length from the first end to the second end extends upward or in an upward inclined direction opposite to the direction of gravity, or in a downward inclined direction of 45 degrees or less relative to the horizontal direction, in the direction in which the first toner is transported; the portion of the second tube longer than half the length from the third end to the fourth end extends upward or in an upward inclined direction, or in a downward inclined direction of 45 degrees or less relative to the horizontal direction, in the direction in which the second toner is transported; the length of the first tube from the first end to the second end is longer than the length of the second tube from the third end to the fourth end; and the cross-sectional area of ​​the internal space of the first tube is narrower than the cross-sectional area of ​​the internal space of the second tube.

[0008] Another aspect of the present invention is an image forming apparatus comprising: a first cartridge for containing a first toner; a second cartridge for containing a second toner; an apparatus body to which the first cartridge and the second cartridge can be attached and detached, comprising: a pump unit for discharging air; a first developing container including a first toner storage section for containing the first toner; a second developing container including a second toner storage section for containing the second toner; a first end communicating with the interior of the first cartridge; and a second end communicating with the interior of the first toner storage section, extending from the first end to the second end and the The device body comprises a first tube through which the first toner passes, a third end communicating with the inside of the second cartridge, and a fourth end communicating with the inside of the first toner storage section, the second tube extending from the third end to the fourth end and through which the second toner passes, the first cartridge comprising a first toner chamber for storing the first toner, a first filter configured to obstruct the passage of the first toner but allow the passage of air, and a first air chamber adjacent to the first toner chamber via the first filter, through which the pump section discharges The first cartridge has a first air chamber provided with a first air intake, a first outlet for discharging the first toner contained in the first toner chamber to the outside of the first cartridge, and a first pipe configured to communicate with the first outlet, through which the first toner discharged from the first outlet passes. The second cartridge has a second toner chamber for containing the second toner, a second filter configured to obstruct the passage of the second toner but allow the passage of air, and a second air chamber adjacent to the second toner chamber via the second filter. The first cartridge has a second air chamber with a second intake port for taking in air discharged from the pump section, a second outlet for discharging the second toner contained in the second toner chamber to the outside of the second cartridge, and a second pipe configured to communicate with the second outlet, through which the second toner discharged from the second outlet passes, and is configured such that the first toner in the first toner chamber is discharged from the first outlet and transported to the first toner storage section via the first tube by air taken in from the first intake port of the first cartridge.The image forming apparatus is configured such that air taken in from the second intake port of the second cartridge causes the second toner in the second toner chamber to be discharged from the second outlet port and transported to the second toner storage section via the second tube, and the total length of the first tube is equal to the total length of the second tube.

[0009] Another aspect of the present invention is an image forming apparatus comprising: a cartridge for containing toner; an apparatus body to which the cartridge can be attached and detached, comprising: a pump unit for discharging air; a developing container including a toner storage section for containing the toner, the developing container being positioned above the cartridge; and a tube having a first end communicating with the inside of the cartridge and a second end communicating with the inside of the toner storage section, extending from the first end to the second end and through which the toner passes; wherein the cartridge comprises: a toner chamber for containing the toner; a filter configured to obstruct the passage of the toner but allow the passage of air; and an air chamber adjacent to the toner chamber via the filter, the air chamber having an intake for taking in air discharged from the pump unit. The image forming apparatus is characterized by having an outlet for discharging the toner contained in the toner chamber to the outside of the cartridge, and a pipe configured to communicate with the outlet and through which the toner discharged from the outlet passes, wherein the toner in the toner chamber is discharged from the outlet and transported to the toner storage section via the tube by air taken in from the intake of the cartridge, and the tube includes a first part and a second part that extend between the first and second ends at an inclination angle greater than 60 degrees with respect to the vertical or horizontal direction in the direction in which the toner is transported, and a third part that extends between the first and second parts in the horizontal or downward inclination direction or in an upward inclination direction of 15 degrees or less with respect to the horizontal direction. [Effects of the Invention]

[0010] According to the present invention, one form of an image forming apparatus can be provided. [Brief explanation of the drawing]

[0011] [Figure 1] A schematic diagram showing an image forming apparatus according to the first embodiment. [Figure 2] A cross-sectional view showing a process cartridge. [Figure 3] (a) is a cross-sectional view showing a toner cartridge with the sealing member open, and (b) is a cross-sectional view showing a toner cartridge with the sealing member closed. [Figure 4] A perspective view showing a toner cartridge cut in the XY plane. [Figure 5] An exploded perspective view showing a toner cartridge cut in the XY plane. [Figure 6] A perspective view showing the filter. [Figure 7] Enlarged view showing the joint between the first and second frame sections. [Figure 8] A bottom view showing the first frame. [Figure 9] A cross-sectional view showing how the toner cartridge is connected to the developing container via a passage. [Figure 10] (a) is a cross-sectional view showing the state before toner discharge has started, and (b) is a cross-sectional view showing the state after toner discharge has started due to air taken in from the intake. (c) is a cross-sectional view showing the state after toner has been discharged further from the state in Figure 10(b), and (d) is a cross-sectional view showing the state in which part of the inclined portion of the filter is exposed. [Figure 11] A block diagram showing a part of the control system of an image forming apparatus. [Figure 12] A plan view showing the toner transport path according to the first embodiment. [Figure 13] (a) is a front view showing the toner transport path through which black toner passes, and (b) is a front view showing the toner transport path through which yellow toner passes. [Figure 14] A front view showing the toner transport path according to the second embodiment. [Figure 15](a) shows a cross-sectional view of a toner conveyance path with a perfect circular cross-section according to the third embodiment, and (b) shows a cross-sectional view of a toner conveyance path with an elliptical cross-section. [Figure 16] A plan view showing a toner conveyance path according to the fourth embodiment. [Figure 17] A plan view showing a toner conveyance path according to the fifth embodiment. [Figure 18] (a) is a schematic diagram showing a toner conveyance path as a comparative example, and (b) is a schematic diagram showing a toner conveyance path according to the sixth embodiment.

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments for carrying out this invention will be illustratively and detailedly described based on examples with reference to the drawings. However, dimensions, materials, shapes, relative arrangements, etc. of the components described in this embodiment should be appropriately changed according to the configuration of the apparatus to which the invention is applied and various conditions. That is, it is not intended to limit the scope of this invention to the following embodiments.

[0013] In addition, examples of the image forming apparatus in the following description include copiers, printers, multifunction printers, commercial printing apparatuses, etc. In such an image forming apparatus, an image is formed on a recording material based on image information input from an external device or image information read from a document. Further, in addition to the main body having an image forming function, the image forming apparatus may be connected with accessory devices such as an optional feeder, an image reading device, a sheet processing device, etc. However, the entire system to which such accessory devices are connected is also a kind of image forming apparatus. The recording material includes sheets of various materials and shapes such as paper like plain paper and cardboard, plastic films, coated paper, sheets with special shapes such as envelopes and index papers, and cloth.

[0014] <The First Embodiment> 〔Overall Configuration〕 First, a first embodiment of the present invention will be described. The image forming apparatus IF according to the first embodiment is an electrophotographic laser beam printer. As shown in Figure 1, the image forming apparatus IF includes an image forming unit 50 for forming an image on a sheet P, a feeding unit 60, a fixing unit 9, and a pair of discharge rollers 5c. The image forming unit 50 includes four process cartridges BY, BM, BC, and BK, which each form toner images of four colors: yellow (Y), magenta (M), cyan (C), and black (K), and a scanner unit 3. The scanner unit 3 is positioned above the process cartridges BY, BM, BC, and BK. Alternatively, an LED exposure unit having an LED array in which multiple LEDs are arranged along the longitudinal direction of the photosensitive drum 1 may be used instead of the scanner unit 3.

[0015] The part of the image forming apparatus IF excluding each process cartridge BY, BM, BC, BK and the toner cartridges CY, CM, CC, CK described later may be referred to as the main body of the image forming apparatus IF or the apparatus body 100. In the following explanation, the toner cartridges CY, CM, CC, CK may simply be referred to as cartridges CY, CM, CC, CK. The process cartridges BY, BM, BC, BK may be detachably supported by the apparatus body 100, or they may be fixed to the apparatus body 100 in a non-detachable manner.

[0016] In this embodiment, the component reference numbers corresponding to yellow, magenta, cyan, and black toners are denoted with subscripts Y, M, C, and K, respectively. The configuration and operation of these subscripted components are substantially the same, except for the difference in toner color. Therefore, in the following, the subscripts Y-K may be omitted and the components described collectively when no particular distinction is necessary. That is, process cartridges BY, BM, BC, and BK may be collectively described as process cartridge B, and toner cartridges CY, CM, CC, and CK may be collectively described as toner cartridge C.

[0017] Furthermore, in the following explanation, unless otherwise specified, it is assumed that the process cartridges BY, BM, BC, BK and toner cartridges CY, CM, CC, CK are in their normal orientation, that is, the orientation when they are mounted on the device body 100, and the directions (X, Y, Z) are defined as follows.

[0018] As shown in Figure 1, the front-to-back direction is indicated by the X-axis, and the direction from the back to the front of the image forming apparatus IF is defined as the X-direction. The X-direction is sometimes referred to as the front direction or the direction towards the viewer. In addition, the downstream side in the X-direction of the image forming apparatus IF is sometimes referred to as the front side, and the upstream side as the back side.

[0019] The left-right direction is indicated by the Z-axis, and the direction from left to right in the image forming apparatus IF is defined as the Z-direction. The Z-direction is sometimes referred to as the right direction. Additionally, the downstream side and the upstream side in the Z-direction of the image forming apparatus IF are sometimes referred to as the right side and left side, respectively.

[0020] The vertical direction is indicated by the Y-axis, and the direction from the bottom to the top of the image forming apparatus IF is defined as the Y-direction. The Y-direction may also be called the upward direction, height direction, or vertical direction. Furthermore, the downstream side in the Y-direction of the image forming apparatus IF may be called the upper side, top surface side, or top surface side, while the upstream side may be called the lower side, bottom surface side, or bottom surface side.

[0021] The X, Y, and Z axes are perpendicular to each other. For example, the X axis is perpendicular to both the Y axis and the Z axis. The plane perpendicular to the X axis is sometimes called the YZ plane, the plane perpendicular to the Y axis is called the ZX plane, and the plane perpendicular to the Z axis is called the XY plane. For example, the XZ plane is a horizontal plane. The X and Z directions are directions along the horizontal XZ plane, i.e., horizontal directions.

[0022] Process cartridge BY comprises a photosensitive drum 1, a developing roller 2, a charging roller 11, and a developing container 12 including a toner storage section 12a for storing toner supplied to the developing roller 2. Similarly, process cartridges BM, BC, and BK each comprise a photosensitive drum, a developing roller, a charging roller, and a developing container including a toner storage section for storing toner supplied to the developing roller. The photosensitive drum 1 is constructed by coating the outer circumference of an aluminum cylinder with an organic photoconductive layer and is rotated by a drive motor (not shown). A photosensitive belt may be used instead of the photosensitive drum 1.

[0023] These four process cartridges BY, BM, BC, and BK are arranged in a line in the X direction. The image forming unit 50 also has transfer rollers 71, 72, 73, and 74 that contact the developing rollers 2 of each process cartridge BY, BM, BC, and BK to form transfer sections Nt1, Nt2, Nt3, and Nt4. For example, transfer roller 71 contacts the photosensitive drum 1 of process cartridge BY to form transfer section Nt1.

[0024] The fixing unit 9 includes a heating roller 9a that is heated by a heater and a pressure roller 9b that presses against the heating roller 9a. Alternatively, instead of the heating roller 9a, a fixing film that rotates while rubbing against the heater or a fixing belt having a conductive layer that is heated by electromagnetic induction may be used.

[0025] The feeding unit 60 is located at the bottom of the image forming apparatus IF. The feeding unit 60 includes a tray 4 that can be pulled out and attached to the apparatus body 100, and a feeding roller 5a that feeds the sheet P contained in the tray 4.

[0026] The main unit 100 of the device is detachably supported by toner cartridges CC, CY, CM, and CK. Each toner cartridge CC, CY, CM, and CK contains toner T that can be supplied to the toner storage section 12a of the developing container 12 of each process cartridge BY, BM, BC, and BK.

[0027] [Image Formation Process] Next, the image forming operation of the image forming apparatus IF configured in this way will be explained. When an image signal is input to the scanner unit 3 from a personal computer (not shown), the scanner unit 3 irradiates the photosensitive drum 1 of each process cartridge BY, BM, BC, and BK with laser light L corresponding to the image signal.

[0028] At this time, the surface of the photosensitive drum 1 is uniformly charged to a predetermined polarity and potential by the charging roller 11, and an electrostatic latent image is formed on the surface when laser light L is irradiated from the scanner unit 3. The electrostatic latent image formed on the photosensitive drum 1 is developed by the developing roller 2, and a toner image is formed on the photosensitive drum 1. That is, toner images of yellow (Y), magenta (M), cyan (C), and black (K) are formed on the photosensitive drum 1 of each process cartridge BY, BM, BC, and BK.

[0029] In parallel with this image formation process, the sheet P contained in the tray 4 of the feeding unit 60 is transported toward the transfer unit Nt1. In the transfer unit Nt1, the yellow (Y) toner image on the photosensitive drum 1 is transferred to the sheet P by a secondary transfer bias applied to the transfer roller 71. Similarly, magenta (M), cyan (C), and black (K) toner images are transferred to the sheet P in the transfer units Nt2, Nt3, and Nt4. After the toner images of each color have been transferred to the sheet P, any toner remaining on the surface of each photosensitive drum is removed by a cleaning device (not shown).

[0030] The sheet P onto which the toner images of each color have been transferred is subjected to predetermined heat and pressure by the heating roller 9a and pressure roller 9b of the fixing unit 9, causing the toner to melt and solidify (fix) to the sheet. After passing through the fixing unit 9, the sheet P is discharged in the direction along the X direction by the discharge roller pair 5c and loaded onto the discharge tray 10 located on the top of the main body 100 of the device.

[0031] [Processing cartridge] Next, we will describe process cartridge B in more detail using Figure 2. Figure 2 is a cross-sectional view showing process cartridge B. Process cartridge B only needs to have a photosensitive drum 1 and process means that act on the photosensitive drum 1. In this embodiment, the process means includes a charging roller 11, a developing roller 2, a developing blade 15, and a cleaning blade 14.

[0032] Furthermore, process cartridge B is composed of a drum unit as an image carrier unit and a developing unit as a developing means. The drum unit has a charging roller 11 located around the photosensitive drum 1 and an elastic cleaning blade 14. The developing unit has a developing roller 2, a developing blade 15, a supply roller 6, a developing container 12 including a toner storage section 12a for storing toner T, and a stirring member 13.

[0033] The stirring member 13 has a rotating shaft 13a and a flexible stirring sheet 13b fixed to the rotating shaft 13a, and stirs the toner T contained in the toner storage section 12a by rotating. The developing container 12 is provided with a passage 24 through which the toner supplied from the toner cartridge C passes, a receiving port 24a for receiving the supplied toner, and an opening 26 for allowing air inside the toner storage section 12a to pass to the outside of the developing container 12. In the orientation when the image forming apparatus IF is in use, the receiving port 24a and the opening 26 are located at the top of the developing container 12, and the opening 26 is covered by a filter 26a. In this embodiment, the opening 26 is composed of a through hole, connecting the inside of the toner storage section 12a to the outside of the developing container 12. The filter 26a is composed of a porous material, for example, resin fibers. The holes in the filter 26a are sized and dense enough to allow the passage of air but restrict the passage of toner T. In other words, filter 26a is configured to allow air to pass through but to prevent toner T from passing through.

[0034] [Toner cartridge general configuration] Next, the schematic configuration of toner cartridges CY, CM, CC, and CK will be described using Figures 3(a) to 8. Figure 3(a) is a cross-sectional view showing toner cartridge C with the sealing member 30 open, and Figure 3(b) is a cross-sectional view showing toner cartridge C with the sealing member 30 closed. Figure 4 is a perspective view showing toner cartridge C cut in the XY plane. Figure 5 is an exploded perspective view showing toner cartridge C cut in the XY plane. Figure 6 is a perspective view showing filter 18. Figure 7 is an enlarged view showing the joint portion of the first frame 32 and the second frame 31. Figure 8 is a bottom view showing the first frame 32.

[0035] The image forming apparatus IF has a front door (not shown) that is supported by the housing of the apparatus body 100 so as to be openable and closable. When the front door is in the closed position, it covers the opening provided at the front of the apparatus body 100, i.e., the downstream end in the X direction. When the front door is in the open position, it opens the opening of the apparatus body 100. The front door can maintain its position when in the open position.

[0036] When the front door is opened from the closed position to the open position, the toner cartridges CY, CM, CC, and CK are exposed to the outside of the image forming apparatus IF through the opening. This allows the user to access the toner cartridges CY, CM, CC, and CK.

[0037] The toner cartridges CY, CM, CC, and CK are located on the downstream side of the device body 100 in the X direction, i.e., on the front side of the device body 100. In other words, the toner cartridges CY, CM, CC, and CK are located on the downstream side of the device body 100 in the sheet discharge direction of the discharge roller pair 5c. Furthermore, the toner cartridges CY, CM, CC, and CK are arranged in the Z direction. That is, the X direction, which is the direction in which the process cartridges BY, BM, BC, and BK are arranged, and the Z direction, which is the direction in which the toner cartridges CY, CM, CC, and CK are arranged, intersect each other.

[0038] The toner cartridges CY, CM, CC, and CK are detachably supported in the X direction relative to the main unit 100. Therefore, the toner cartridges CY, CM, CC, and CK can be replaced without removing the process cartridges BY, BM, BC, and BK from the main unit 100. The toner cartridges CY, CM, CC, and CK are located on the front side of the main unit 100 and are exposed by opening the front door, allowing for easy replacement.

[0039] Toner cartridges CY, CM, CC, and CK each have a similar configuration, and in the following, these toner cartridges CY, CM, CC, and CK will be collectively referred to as toner cartridge C. Furthermore, in the following description, unless otherwise specified, it is assumed that toner cartridge C assumes the orientation described below, and the directions (X, Y, Z) are defined as shown in Figures 3(a) to 16. That is, the description assumes that toner cartridge C assumes an orientation in which the toner chamber 16, filter 18, and air chamber 17 are arranged from top to bottom in this order with respect to the direction of gravity G (opposite to the Y direction; see Figure 3(a)), and that the short direction (Z direction) and long direction (X direction) of toner cartridge C are parallel to the horizontal direction perpendicular to the direction of gravity G.

[0040] In this orientation, the direction opposite to the Y direction is the direction of gravity, and the toner cartridge C is oriented in a predetermined direction where at least a part of the toner chamber 16 is above the air chamber 17. In this case, the short side of the toner cartridge C is the Z direction, the long side is the X direction, and the direction opposite to the direction of gravity is the Y direction. That is, the direction of gravity G is the direction in which the second frame 31 and the first frame 32, which will be described later, are aligned. In other words, the direction of gravity G is the direction in which the toner chamber 16 and the air chamber 17 are aligned. The X direction is the long side of the toner cartridge C when viewed in the direction of gravity G. The Z direction is the short side of the first frame 32 that intersects both the X and Y directions, and is also the long side of the developing container 12.

[0041] The front-to-back direction of toner cartridge C is indicated by the X-axis, with the direction from the back to the front being defined as the X-direction. The X-direction is sometimes referred to as the front direction or the direction towards the viewer. Additionally, the downstream side of toner cartridge C in the X-direction is sometimes referred to as the front side, and the upstream side as the back side.

[0042] The left-right direction of toner cartridge C is indicated by the Z-axis, and the direction from left to right of toner cartridge C is defined as the X-direction. The Z-direction is sometimes referred to as the right direction. Additionally, the downstream side of toner cartridge C in the Z-direction is sometimes referred to as the right side, and the upstream side as the left side.

[0043] The vertical direction of toner cartridge C is indicated by the Y-axis, and the direction from the bottom to the top of toner cartridge C is defined as the Y-direction. The Y-direction may also be called the upward direction, height direction, or vertical direction. Furthermore, the downstream side of toner cartridge C in the Y-direction may be called the upper side, top surface side, or top surface side, while the upstream side may be called the lower side, bottom surface side, or bottom surface side.

[0044] As shown in Figures 3(a) to 5, the toner cartridge C includes a first frame 32 as a first container, a second frame 31 as a second container, a filter 18, and a discharge pipe 27 as a pipe. In this embodiment, the first frame 32 and the second frame 31 are made of resin material, but they may be made of paper or the like. As will be described in detail later, the filter 18 is held in a state sandwiched between the first frame 32 and the second frame 31.

[0045] The internal space of the toner cartridge C is divided into a toner chamber 16 and an air chamber 17 by a filter 18. Specifically, the toner chamber 16 is composed of a first frame 32 and a filter 18, and the air chamber 17 is composed of a second frame 31 and a filter 18. The air chamber 17 is located below the filter 18, and the toner chamber 16 is located above the filter 18. In other words, the air chamber 17 is adjacent to the toner chamber 16 via the filter 18. There are no partitions within the air chamber 17, and it is the only chamber (room, space) adjacent to the toner chamber 16 via the filter 18.

[0046] The toner chamber 16 is configured to contain toner T, which is supported by gravity by the filter 18 within the toner chamber 16. The air chamber 17 does not contain toner T. The filter 18 is made of a porous material, for example, resin fibers. The pores of the filter 18 are of a size and density that allows air to pass through but restricts the passage of toner T. In other words, the filter 18 is configured to allow air to pass through but to prevent the passage of toner T.

[0047] The back of the first frame 32 is provided with an outlet 16a through which toner in the toner chamber 16 is discharged to the outside of the toner cartridge C. In other words, the toner chamber 16 is provided with an outlet 16a. The outlet 16a is made up of a through hole that penetrates the first frame 32 in the X direction. The bottom surface 31d of the second frame 31 is provided with an intake 20 made up of a through hole that penetrates the second frame 31 in the Y direction. In other words, the air chamber 17 is provided with an intake 20. The outlet 16a and the intake 20 are connected to the outside of the toner cartridge C.

[0048] As shown in Figure 1, the main body 100 of the image forming apparatus IF includes a pump 35 and an air supply pipe 21. The air supply pipe 21 connects the pump 35 to the intake 20 of the toner cartridge C, and the pump 35 is configured to supply air to the air chamber 17 of the toner cartridge C via the air supply pipe 21. The pump 35 is located below the toner cartridge C. The pump 35 is composed of, but is not limited to, a positive displacement pump such as a reciprocating pump or a rotary pump. For example, the pump 35 may be composed of a non-positive displacement pump such as a centrifugal pump, a propeller pump, or a viscous pump.

[0049] Reciprocating pumps use the reciprocating motion of a piston or plunger to perform suction and discharge, and include piston pumps, plunger pumps, and diaphragm pumps. Rotary pumps use the rotational motion of gears or rotors to perform suction and discharge, and include gear pumps, screw pumps, and vane pumps.

[0050] In this embodiment, the device body 100 is equipped with the same number of pumps 35 as the number of toner cartridges C. That is, there are four pumps 35 corresponding to the four toner cartridges CY, CM, CC, and CK. To distinguish between them, as shown in Figure 11, the pumps that individually discharge air to toner cartridges CY, CM, CC, and CK are designated as pumps 35Y, 35M, 35C, and 35K. The four pumps 35Y, 35M, 35C, and 35K are connected to toner cartridges CY, CM, CC, and CK via air supply pipes 21. The configurations of pumps 35Y, 35M, 35C, and 35K are substantially the same.

[0051] In this embodiment, the pump 35 was connected to the intake 20 via the air supply pipe 21, but this is not limited to this configuration. For example, the pump 35 may be directly connected to the intake 20 of the toner cartridge C, or it may be connected to the intake 20 via a passage formed by the frame of the device body 100 or the like.

[0052] Furthermore, the four pumps 35Y, 35M, 35C, and 35K may be configured as a single pump unit, or as two or three separate pump units. In this embodiment, the pumps 35Y, 35M, 35C, and 35K are provided in the main unit 100 of the device, but they may also be provided in the toner cartridges CY, CM, CC, and CK, or in the process cartridges BY, BM, BC, and BK, respectively.

[0053] Furthermore, the discharge port 16a provided on the first frame 32 of the toner cartridge C opens toward the upstream direction in the X direction. Therefore, when the toner cartridge C is mounted on the device body 100 facing toward the upstream direction in the X direction, it is easy to engage the discharge port 16a with the toner transport paths T1 to T4, which will be described later, provided on the device body 100.

[0054] In addition to the arrangement described above, the discharge port 16a may be provided on the bottom surface 31d or top surface of the toner cartridge C, and the intake port 20 may be provided on the back or top surface of the toner cartridge C. Furthermore, if there is sufficient space in the main body 100 of the device, the discharge port 16a and the intake port 20 may be provided on both the left and right sides of each side of the toner cartridge C.

[0055] Furthermore, the first frame 32 of the toner cartridge C supports a sealing member 30 that seals the discharge port 16a, so that it can rotate around a pivot axis 30a. When the toner cartridge C is not mounted on the device body 100 and the discharge port 16a of the toner cartridge C is not connected to the passage 24, the sealing member 30 is in the closed position shown in Figure 3(a). In the closed position, the sealing member 30 seals the discharge port 16a, preventing toner in the toner chamber 16 from leaking to the outside of the toner cartridge C.

[0056] On the other hand, when the toner cartridge C is mounted on the device body 100 and the discharge port 16a of the toner cartridge C is connected to the passage 24, the sealing member 30 is in the open position shown in Figure 3(b). In the open position, the sealing member 30 opens the discharge port 16a, allowing toner T to be supplied from the toner cartridge C to the process cartridge B via the passage 24. Note that the sealing member 30 is not limited to an opening / closing member as in this embodiment, but may also be composed of, for example, a seal that can be peeled off from the toner cartridge C, or a sliding member that can slide.

[0057] As shown in Figures 3(a) to 5, the first frame 32 has a first box portion that forms the toner chamber 16, and a first flange portion 32a that extends substantially horizontally from the lower end of the first box portion toward the outside of the toner chamber 16. The first box portion is formed in a substantially rectangular parallelepiped shape. The first flange portion 32a is formed around the entire circumference of the lower end of the first box portion.

[0058] Furthermore, as shown in Figure 8, a plurality of ribs 32d are provided on the inner wall of the first box portion of the first frame 32. The plurality of ribs 32d extend inward into the toner chamber 16, corresponding to the region where the second flange portion 31a of the second frame 31 is formed. The plurality of ribs 32d face the second flange portion 32a of the second frame 31 in the Y direction.

[0059] The second frame 31 is formed separately from the first frame 32 and has a second box portion that forms the air chamber 17, and a second flange portion 31a that extends substantially horizontally from the upper end of the second box portion toward the outside of the air chamber 17. The second flange portion 31a is formed around the entire circumference of the upper end of the second box portion.

[0060] As shown in Figures 3(a) to 6, the filter 18 has a bottom surface portion 18e that serves as a partition separating the air chamber 17 and the toner chamber 16, and an outer edge portion 18a that is sandwiched and held by the first flange portion 32a and the second flange portion 31a. The bottom surface portion 18e is composed of a plurality of inclined portions 18c that are formed to slope downward in the direction of gravity G as they approach the lowest part 18b of the filter 18, and constitutes the bottom surface of the toner chamber 16. The lowest part 18b is located in the center of the filter 18 in the X and Z directions.

[0061] The filter 18 is made of a filter material formed by, for example, a heat press, or a fibrous sheet material. The filter 18 is formed from a single continuous member, and the bottom surface 18e of the filter 18 is configured to be parallel to the shape of the bottom surface of the second frame 31.

[0062] The frame of the toner cartridge C is constructed such that the first flange portion 32a and the second flange portion 31a are joined together by ultrasonic welding, preventing air from leaking between them. The first flange portion 32a and the second flange portion 31a may be fixed to each other not only by ultrasonic welding, but also by heat welding, adhesives such as double-sided tape or hot melt, or screws.

[0063] The first flange portion 32a and the second flange portion 31a are joined together, so that the outer edge portion 18a of the filter 18 and the sealing member 34 are sandwiched between the multiple ribs 32d of the first frame 32 and the second flange portion 31a. The sealing member 34 is made of a flexible material such as rubber or silicone. In this way, the filter 18 is held in place by being sandwiched between the first frame 32 and the second frame 31 together with the sealing member 34. If the holding force of the filter 18 is insufficient, the entire circumference of the outer edge portion 18a of the filter 18 may be bonded to at least one of the first flange portion 32a and the second flange portion 31a. This allows the filter 18 to be held with high holding force. The sealing member 34 may also be omitted.

[0064] Inside the toner chamber 16, a cylindrical discharge pipe 27 is arranged as shown in Figures 3(a) to 5. The discharge pipe 27 has an inlet 27a that opens downward in the direction of gravity G, and an outlet 27b that opens backward, i.e., upstream in the direction of X, and communicates with the outlet 16a of the toner cartridge C, and communicates with the outside of the toner cartridge C. The outlet 27b is located above the inlet 27a. The discharge pipe 27 has a first pipe section with an inlet 27a that extends in the direction of Y or the direction of gravity G, and a second pipe section with an outlet 27b that is connected to the outlet 16a and extends in the direction of X, and is bent in the middle. In this way, the discharge pipe 27 connects the inlet 27a and the outlet 27b. The inlet 27a, which is the end of the discharge pipe 27 opposite to the outlet 27b, is positioned to face the lowest part 18b, which is part of the filter 18, with a gap in the direction of gravity G. The discharge pipe 27 is appropriately constructed from a flexible tube made of a resin material such as rubber or a silicone material, or from a hollow member made of a resin or metal pipe.

[0065] As shown in Figures 4 and 8, support portions 32b and 32c extend from the inner circumferential surface of the first frame 32. Support portion 32b extends in the -Y direction (gravity direction G) from the inner circumferential surface on the upper side of the first frame 32, and support portion 32c extends in the X direction from the inner circumferential surface on the back side of the first frame. These support portions 32b and 32c support the portion of the discharge pipe 27 near the inlet 27a and the portion near the outlet 27b, respectively. Note that the support portions 32b and 32c may be molded integrally with the first box portion of the first frame 32 during the molding of the first frame 32, or they may be constructed separately from the first box portion.

[0066] Here, we will summarize the toner cartridge CK, which supplies toner to the developer container 12K, which serves as the first developer container for process cartridge BK, and the toner cartridge CY, which supplies toner to the developer container 12Y, which serves as the second developer container for process cartridge BY. Developer container 12K has a toner storage section 12a, which serves as the first toner storage section. Developer container 12Y has a toner storage section 12a, which serves as the second toner storage section. Toner cartridge CK, as the first cartridge, has a toner chamber 16, which serves as the first toner chamber, and a filter 18, which serves as the first filter. Furthermore, toner cartridge CK has an air chamber 17 adjacent to the toner chamber 16 via the filter 18, which serves as the first air chamber, and is provided with an intake 20, which serves as the first intake for taking in air from outside toner cartridge CK. Furthermore, the toner cartridge CK is located in the toner chamber 16 and has a discharge pipe 27 as a first pipe through which the toner T passes, extending from an inlet 27a as a first inlet to an outlet 27b as a first outlet.

[0067] Similarly, the toner cartridge CY, as a second cartridge, has a toner chamber 16, which is a second toner chamber, and a filter 18, which is a second filter, with an outlet 16a, which is a second discharge port. The toner cartridge CY also has an air chamber 17, which is a second air chamber, adjacent to the toner chamber 16 via the filter 18, and has an inlet 20, which is a second intake port. Furthermore, the toner cartridge CY has a discharge pipe 27, which is a second pipe, provided in the toner chamber 16, extending from an inlet 27a, which is a second inlet port, to an outlet 27b, which is a second outlet port, through which the toner T passes. The toner cartridge CK is connected to a pump 35K, which is a first pump (see Figure 11), and the toner cartridge CY is connected to a pump 35Y, which is a second pump (see Figure 11).

[0068] [Toner transport mechanism] Next, using Figures 1, 3(a)(b), and 9, the mechanism by which toner contained in the toner chamber 16 of toner cartridge C is transported to the developing container 12 of process cartridge B will be explained. Figure 9 is a cross-sectional view showing how toner cartridge C is connected to the developing container 12 via the passage 24. As shown in Figures 1 and 9, air discharged from the pump 35 is taken into the air chamber 17 via the air supply pipe 21 and the intake 20 of toner cartridge C. This air then fills the air chamber 17, passes through the filter 18, and flows into the toner chamber 16.

[0069] Air flowing into the toner chamber 16 penetrates between the toner particles T, causing the toner T to become fluid. The influx of air from the pump 35 creates positive pressure inside the toner cartridge C, and the air attempts to exit the toner cartridge C through the discharge pipe 27 and the discharge port 16a. At this time, the toner T in the toner chamber 16 is moved along with the air through the discharge pipe 27 and discharged to the outside of the toner cartridge C through the discharge port 16a. In other words, the discharge pipe 27 guides the toner in the toner chamber 16 along with the air from the inlet 27a to the discharge port 16a.

[0070] As in this embodiment, by providing an air chamber 17, which is a highly sealed space, between the pump 35 and the filter 18, the air discharged from the pump 35 is efficiently directed to the filter 18 without being dispersed outside the toner cartridge C. For example, in situations where the toner T in the toner chamber 16 agglomerates, such as when the toner cartridge C is subjected to vibration or left unattended for a long time, the pressure required to allow air to flow into the toner chamber 16 through the filter 18 may be high. Even in this case, by continuously supplying air from the pump 35 to the air chamber 17 and increasing the pressure (atmospheric pressure) in the air chamber 17, it becomes possible to supply air to the toner chamber 16 through the filter 18. Furthermore, by providing the air chamber 17, it is sufficient for the pump 35 to generate enough pressure to continue supplying air into the air chamber 17 until the pressure is sufficient for air to pass from the filter 18 into the toner chamber 16. Therefore, since there are no special requirements for the discharge speed or discharge volume of the pump 35, it is possible to use a small pump unit, which contributes to the miniaturization of the device.

[0071] Furthermore, in this embodiment, the air taken in from the intake port 20 of the toner cartridge C has only one outlet, the discharge port 16a. As a result, the airflow within the toner cartridge C is stable, and the toner T contained in the toner chamber 16 can be stably discharged to the outside of the toner cartridge.

[0072] Furthermore, by not providing any vents or outlets inside the toner cartridge C except for one outlet 16a, it is possible to stably discharge the toner T using only the power of the pump 35 that discharges air toward the intake 20. When multiple air outlets are provided, it becomes difficult to manage the flow of toner and air, so in order to stably transport the toner, it may be necessary to have a configuration that sucks up the toner and air and discharges them to the outside of the toner cartridge C. With the configuration of this embodiment, it is possible to stably discharge the toner T without having to provide a separate pump to suck up air, so that stably transporting the toner T can be achieved with a simpler configuration.

[0073] The toner T discharged from the discharge port 16a is supplied to the upstream end of the developing container 12 in the Y direction via the passage 24. Here, as shown in Figure 2, a stirring member 13 for stirring the toner inside the developing container 12 is rotatably provided in the toner storage section 12a of the developing container 12.

[0074] The toner in the toner storage section 12a is leveled by the rotation of the stirring member 13. In this embodiment, the stirring member 13 consists of a rotating shaft 13a and a stirring sheet 13b fixed to the rotating shaft 13a, but it is not limited to this configuration. For example, the stirring member 13 may consist of a screw configured to transport the toner in the toner storage section 12a of the developing container 12 along the Z direction.

[0075] Since air as well as toner T flows into the developing container 12, the internal pressure inside the developing container 12 increases. Therefore, in this embodiment, as shown in Figures 3(a)(b) and 9, an opening 26 is provided on the top surface of the developing container 12, and this opening 26 is covered by a filter 26a. As a result, the toner that flows into the developing container 12 is restricted from being discharged to the outside by the filter 26a and remains inside the developing container 12. On the other hand, at least a portion of the air that flows into the developing container 12 passes through the filter 26a and is discharged to the outside of the developing container 12. This suppresses the rise in internal pressure of the developing container 12 and allows for smooth replenishment of toner to the developing container 12.

[0076] As described above, the toner contained in the toner cartridge C is transported to the developing container 12 along with air and replenished in the developing container 12. By transporting the toner using air, the design flexibility of the toner transport path is increased, and since components such as screws for transporting the toner are not required, the number of parts can be reduced, and costs can be lowered.

[0077] Furthermore, as described above, the inlet 27a of the discharge pipe 27 is positioned opposite the lowest part 18b of the filter 18 with a gap between them. Since the filter 18 is held in a downward-sloping position toward the lowest part 18b, when the amount of toner remaining in the toner chamber 16 becomes low, the toner, which has been fluidized by the air, moves along the slope of the filter 18 and collects at the lowest part 18b. In other words, the toner in the toner chamber 16 can be guided toward the inlet 27a of the discharge pipe 27.

[0078] Therefore, even when the amount of toner remaining in the toner chamber 16 becomes low, the toner that has accumulated at the bottom 18b can be efficiently discharged from the inlet 27a of the discharge pipe 27 through the outlet 16a to the outside of the toner cartridge C. The outlet 16a is located above the inlet 27a and the bottom surface 18e of the filter 18, but the toner is transported from the inlet 27a to the outlet 16a by air. Thus, the amount of toner that remains in the toner chamber 16 without being replenished can be reduced.

[0079] [Changes in toner ejection status] Figures 10(a) to 10(d) are cross-sectional views illustrating the changes in the discharge state when toner T contained in the toner chamber 16 is discharged from the toner cartridge C. Figure 10(a) is a cross-sectional view showing the state in which toner T discharge has not yet begun, and Figure 10(b) is a cross-sectional view showing the state in which toner T discharge has begun due to air taken in from the intake port 20. Figure 10(c) is a cross-sectional view showing the state in which toner T has been discharged further from the state in Figure 10(b), and Figure 10(d) is a cross-sectional view showing the state in which the inclined portion 18c of the filter 18 is partially exposed.

[0080] As shown in Figure 10(a), when air is pumped from the intake 20 into the air chamber 17 of the toner cartridge C by the pump 35, the air flows through the filter 18 and discharge pipe 27 towards the discharge port 16c, which is the only outlet of the toner cartridge C. At this time, the air flows, entraining the toner T, so the toner T enters the intake 27a with the air and is then transported through the discharge pipe 27 towards the discharge port 16a, and discharge from the discharge port 16a begins. As a result, the amount of toner T contained in the toner chamber 16 decreases, and the state transitions from Figure 10(a) to Figure 10(b).

[0081] As shown in Figure 10(b), when the amount of toner T in the toner chamber 16 decreases due to the discharge of toner T, the surface level of the toner T near the inlet 27a drops with respect to gravity. As a result, the toner T contained in the toner chamber 16 begins to collapse from around the inlet 27a. At this time, the toner T is fluidized by the inflow of air that has passed through the filter 18, and the toner T is transported along the slope of the inclined section 18c toward the lowest point 18b. As long as the inflow of air from the intake 20 continues, the toner T near the lowest point 18b enters the discharge pipe 27 through the inlet 27a, passes through the discharge pipe 27 with the air, and is discharged from the outlet 16a. If the discharge of toner T continues, the surface level of the toner T contained in the toner chamber 16 will drop further, transitioning from the state in Figure 10(b) to the state in Figure 10(c) and then to the state in Figure 10(d).

[0082] As shown in Figure 10(d), as the toner T in the toner storage section 12a decreases, a portion of the inclined section 18c of the filter 18 becomes exposed. In this state, the airflow rate of the filter 18 and the pump flow rate are set so that air discharged from the pump 35 blows out from the entire bottom surface 18e of the filter 18, regardless of whether there is toner on the filter 18 or not.

[0083] Furthermore, the inclination angle of the inclined section 18c and the airflow rate supplied by the pump 35 also affect the toner T discharge performance. Increasing the angle of the inclined section 18c is effective in discharging toner T from the entire toner chamber 16. However, if the angle of the inclined section 18c is too large, the capacity of toner T that can be contained in the toner chamber 16 will decrease compared to a configuration with a smaller angle of the inclined section 18c. This may make it difficult to achieve miniaturization of the toner cartridge C when trying to contain the desired amount of toner T. Therefore, from the standpoint of securing capacity and miniaturizing the toner cartridge C, it is more desirable to set the angle of the inclined section 18c as small as possible while still being able to discharge toner T.

[0084] [Positioning of the discharge pipe] As shown in Figures 3(a) and 3(b), the first frame 32 can position the discharge pipe 27 such that its inlet 27a faces the lowest part 18b of the filter 18 by engaging the support portion 31b with the discharge pipe 27. Here, the position of the inlet 27a in the toner chamber 16 relative to the lowest part 18b of the filter 18 affects the discharge of toner T. As shown in Figures 10(a) to 10(c), the toner T contained in the toner chamber 16 is fluidized by the inflow of air and transported toward the lowest part 18b by the configuration of the inclined portion 18c. Therefore, in the configuration of this embodiment, it is most desirable from the viewpoint of toner T discharge to provide the inlet 27a in the vicinity of the lowest part 18b.

[0085] For example, if the discharge pipe 27 is made of a flexible member without a support part 31b inside the toner chamber 16, the position of the inlet 27a may change due to stimuli such as shocks and vibrations to the toner cartridge C or the movement of toner T. If the position of the inlet 27a shifts away from the vicinity of the lowest part 18b, the amount of toner T discharged may also change, since the position where the most toner T accumulates inside the toner chamber 16 is near the lowest part 18b.

[0086] In particular, as shown in Figure 10(c), when the amount of toner T in the toner chamber 16 decreases, if the position of the inlet 27a moves to a position where there is little or no toner T, it becomes difficult to send the toner T to the discharge pipe 27 even if air is introduced from the intake port 20. As a result, the amount of toner T remaining in the toner chamber 16 may increase compared to when the inlet 27a is positioned near the bottom 18b. In other words, by properly positioning the inlet 27a, toner T can be discharged stably from the toner cartridge C to the outside. Furthermore, the amount of toner T remaining in the toner chamber 16 can be controlled, and excess toner T remaining in the toner chamber 16 can be suppressed when toner T is not discharged from the discharge port 16a due to the inflow of air into the intake port 20.

[0087] [Control System] Figure 11 is a block diagram showing a part of the control system of an image forming apparatus IF. As shown in Figure 11, the image forming apparatus IF has a control unit 40. The control unit 40 has a CPU (Central Processing Unit) 41, a ROM (Read Only Memory) 42, and a RAM (Random Access Memory) 43. The ROM 42 stores various programs, and the CPU 41 reads and executes programs from the ROM 42. The RAM 43 is used as a workspace for the CPU 41.

[0088] The control unit 40 is connected to pump drive units 36Y, 36M, 36C, and 36K, which drive the pumps 35Y, 35M, 35C, and 35K respectively. In this embodiment, the pumps 35Y, 35M, 35C, and 35K are composed of diaphragm pumps. The pump drive units 36Y, 36M, 36C, and 36K are each composed of, for example, a motor, a cam, and a crank, and the rotation of the motor is converted into reciprocating motion by the cam and crank and transmitted to each pump. The pumps 35Y, 35M, 35C, and 35K also constitute the pump unit 135. The control unit 40 can control the pump drive units 36Y, 36M, 36C, and 36K independently of each other, and can replenish toner of any color at any time.

[0089] [Specific layout of the passageway] Next, the specific configuration of the passage 24 connecting toner cartridge C and process cartridge B will be explained using Figures 12 and 13(a) and 13(b). Figure 12 is a plan view showing toner transport paths QY, QM, QC, and QK. Figure 13(a) is a front view showing toner transport path QK through which black toner passes, and Figure 13(b) is a front view showing toner transport path QY through which yellow toner passes. In the above explanation, toner cartridge C and the developing container 12 of process cartridge B were connected by the passage 24, but in this embodiment, there are four toner cartridges C and four process cartridges B (developing containers 12). The passage 24 has multiple toner transport paths QY, QM, QC, and QK that connect these four toner cartridges and four developing containers, respectively. Hereinafter, the developing container of process cartridge BY will be referred to as developing container 12Y, and the developing container of process cartridge BM will be referred to as developing container 12M. Furthermore, the developing container for process cartridge BC is designated as developing container 12C, and the developing container for process cartridge BK is designated as developing container 12K.

[0090] As shown in Figure 12, toner cartridge CY and developer container 12Y are connected by toner transport path QY. Toner cartridge CM and developer container 12M are connected by toner transport path QM. Toner cartridge CC and developer container 12C are connected by toner transport path QC. Toner cartridge CK and developer container 12K are connected by toner transport path QK. Through these toner transport paths QY, QM, QC, and QK, toner T of each color is transported along with air from toner cartridges CY, CM, CC, and CK to developer containers 12Y, 12M, 12C, and 12K.

[0091] In this embodiment, the toner cartridges CY, CM, CC, and CK are aligned in the X direction, and the developing containers 12Y, 12M, 12C, and 12K are aligned in the Z direction upstream of the toner cartridges CY, CM, CC, and CK in the X direction. That is, the toner cartridges CY, CM, CC, and CK and the developing containers 12Y, 12M, 12C, and 12K are arranged along the same XZ plane, which is a horizontal plane. The toner transport paths QY, QM, QC, and QK extend mainly along the horizontal direction.

[0092] In the toner transport paths QY, QM, QC, and QK, which mainly extend horizontally, the toner transport force decreases as the distance between the toner cartridge C and the developer container 12 increases. Furthermore, if the toner transport forces of each color toner differ from one another, there is a risk that the toner supply to the developer container corresponding to the toner with the lowest transport force may not keep up. In particular, in print jobs with large image areas, the toner supply to the developer container may not keep up. In addition, there is a risk that the developer container corresponding to the toner with the highest transport force may become full, causing toner to overflow from that container.

[0093] Furthermore, changing the type of pump 35 connected to each toner cartridge or the type of pump drive unit (36Y, etc.) that drives the pump 35 in order to compensate for the difference in toner transport force of each color toner would complicate the device and increase costs. Therefore, in this embodiment, the difference in toner transport force of each color toner is reduced by making the inner diameters of the toner transport paths QY, QM, QC, and QK, which have different lengths, different from each other.

[0094] As shown in Figure 12, the toner transport paths QY, QM, QC, and QK are flexible cylindrical tubes that can be bent. The lengths of the toner transport paths QY, QM, QC, and QK increase in the order of QY, QM, QC, and QK.

[0095] More specifically, as shown in Figure 13(a), the toner transport path QK through which the black toner, as the first toner, passes has, for example, a first passage QKa, a second passage QKb, and a third passage QKc. The first passage QKa has a first end EK1 connected to the outlet 16a of the toner cartridge C, and extends upstream in the X direction, i.e., horizontally, from the first end EK1. The second passage QKb extends in the K direction, i.e., vertically, from the first passage QKa. The third passage QKc extends upstream in the X direction, i.e., horizontally, from the upper end of the second passage QKb, and has a second end EK2 connected to the developer container 12K of the process cartridge BK. In other words, the first end EK1 communicates with the inside of the toner cartridge CK, and the second end E2 communicates with the toner storage section 12a of the developer container 12K. The toner transport path QK extends from the first end EK1 to the second end EK2.

[0096] As shown in Figure 13(b), the toner transport path QY through which the yellow toner, as the second toner, passes has, for example, a first passage QYa, a second passage QYb, and a third passage QYc. The first passage QYa has a third end EY1 connected to the outlet 16a of the toner cartridge C, and extends upstream in the X direction, i.e., horizontally, from the third end EY1. The second passage QYb extends in the Y direction, i.e., vertically, from the first passage QYa. The third passage QYc extends upstream in the X direction, i.e., horizontally, from the upper end of the second passage QYb, and has a fourth end EY2 connected to the developer container 12Y of the process cartridge BY. In other words, the third end EY1 communicates with the inside of the toner cartridge CY, and the fourth end E2 communicates with the toner storage section 12a of the developer container 12Y. The toner transport path QY extends from the third end EY1 to the fourth end EY2.

[0097] As shown in Figure 13(a), the combined length of the horizontally extending portions of the first passage QKa and the second passage QKc is longer than half the length of the toner transport path QK from its first end EK1 to its second end EK2. Also, as shown in Figure 13(b), the combined length of the horizontally extending portions of the first passage QYa and the second passage QYc is longer than half the length of the toner transport path QY from its first end EY1 to its second end EY2. Note that these first passage QKa and the second passage QKc, and the first passage QYa and the second passage QYc do not necessarily have to extend horizontally. For example, the first passage QKa and the second passage QKc, and the first passage QYa and the second passage QYc may be provided to extend in a downward sloping direction or an upward sloping direction of 45 degrees or less relative to the horizontal direction in the direction in which the toner is transported.

[0098] Furthermore, although the explanation will be omitted, the portions of the toner transport paths QM and QC that extend horizontally are also longer than half the total length of each toner transport path QM and QC. In this configuration of toner transport paths QY, QM, QC, and QK, in this embodiment, the inner diameters of the toner transport paths QY, QM, QC, and QK are set to increase in the order of QY, QM, QC, and QK.

[0099] In other words, if the lengths of the toner transport paths QY, QM, QC, and QK are L1Y, L1M, L1C, and L1K, and the inner diameters of the toner transport paths QY, QM, QC, and QK are D1Y, D1M, D1C, and D1K, then these lengths and inner diameters satisfy the following relationship. L1Y <L1M<L1C<L1K ···(1) D1Y <D1M<D1C<D1K ···(2)

[0100] Furthermore, since the inner circumferential surfaces of the toner transport paths QY, QM, QC, and QK in this embodiment are each circular in shape, the cross-sectional areas A1Y, A1M, A1C, and A1K of the internal spaces of the toner transport paths QY, QM, QC, and QK satisfy the following relationship. A1Y <A1M<A1C<A1K ···(3)

[0101] As described above, in the toner transport paths QY, QM, QC, and QK that extend horizontally, the toner transport force decreases as the distance between the toner cartridge C and the developer container 12 increases. Therefore, by increasing the inner diameter (cross-sectional area) of the longer toner transport paths QY, QM, QC, and QK, the pressure loss in the toner transport paths QY, QM, QC, and QK can be leveled. As a result, the toner transport force for each color of toner can be made uniform, and the amount of toner transported for each color can be stabilized.

[0102] For example, the length L1K of the toner transport path QK, which is the length from the first end EK1 to the second end EK2, is longer than the length L1Y of the toner transport path QY, which is the length from the third end EY1 to the fourth end EY2. In this case, the cross-sectional area A1K of the internal space of the toner transport path QK is larger than the cross-sectional area A1Y of the internal space of the toner transport path QY. This is because the inner diameter D1K of the toner transport path QK is larger than the inner diameter D1Y of the toner transport path QY.

[0103] This allows the same type of pump to be used for the four pumps 35 that transport the four colors of toner, and these pumps can be appropriately controlled by the same pump drive unit (36Y, etc.). Therefore, the cost of the image forming apparatus IF can be reduced. In addition, since the inner diameters of the toner transport paths QY, QM, QC, and QK are all different, the toner transport paths QY, QM, QC, and QK are easier to identify, and assembly errors when assembling the toner transport paths QY, QM, QC, and QK can be reduced.

[0104] <Second Embodiment> Next, a second embodiment of the present invention will be described. In the second embodiment, the toner transport paths QY, QM, QC, and QK of the first embodiment extend along the vertical direction (direction of gravity). For this reason, components similar to those in the first embodiment will not be shown in the figures, or will be described using the same reference numerals in the figures.

[0105] Figure 14 is a front view showing the toner transport paths Q2Y, Q2M, Q2C, and Q2K according to the second embodiment. In this embodiment, the toner cartridges CY, CM, CC, and CK are aligned in the X direction, and the developing containers 122Y, 122M, 122C, and 122K are also aligned in the X direction. Furthermore, the developing containers 122Y, 122M, 122C, and 122K are arranged in the order of 122Y, 122M, 122C, and 122K in the vertical direction (Y direction) from bottom to top. That is, the toner cartridges CY, CM, CC, and CK and the developing containers 122Y, 122M, 122C, and 122K are arranged along the same YZ plane, which is a vertical plane. The toner transport paths Q2Y, Q2M, Q2C, and Q2K extend along the direction of gravity G.

[0106] As shown in Figure 14, the toner transport path Q2K through which the black toner passes has a first end EK3 that communicates with the inside of the toner cartridge CK and a second end EK4 that communicates with the toner storage section of the developing container 122K, and extends from the first end EK3 to the second end EK4. The toner transport path Q2K also has a vertical section Q2Ka that extends in the Y direction, which is the upward direction opposite to the direction of gravity G in the direction in which the black toner is transported.

[0107] Furthermore, the toner transport path Q2Y through which the yellow toner passes has a third end EY3 that communicates with the inside of the toner cartridge CY and a fourth end EY4 that communicates with the toner storage section of the developing container 122Y, and extends from the third end EY3 to the fourth end EY4. The toner transport path Q2Y also has a vertical section Q2Ya that extends in the Y direction in the direction in which the yellow toner is transported.

[0108] The length of the vertical section Q2Ka, which extends in the Y direction (vertical direction), is longer than half the length of the toner transport path Q2K from the first end EK3 to the second end EK4. Similarly, the length of the vertical section Q2Ya, which extends in the Y direction (vertical direction), is longer than half the length of the toner transport path QYK from the third end EY3 to the fourth end EY4. Note that these vertical sections Q2Ka and Q2Ya do not necessarily have to extend in the Y direction (vertical direction). For example, the vertical sections Q2Ka and Q2Ya may be provided to extend in an upward inclined direction or in a downward inclined direction of 45 degrees or less relative to the horizontal direction in the direction in which the toner is transported.

[0109] Furthermore, although I will omit the explanation, the portions of the toner transport paths Q2M and Q2C that extend along the Y direction are also longer than half the total length of each toner transport path Q2M and Q2C.

[0110] When toner T is transported vertically upward along toner transport paths Q2Y, Q2M, Q2C, and Q2K, the required pressure increases in proportion to the amount of toner being lifted. Therefore, the longer the toner transport path in the vertical direction, the greater the pressure required for toner transport. In this embodiment, the inner diameters of the toner transport paths Q2Y, Q2M, Q2C, and Q2K are made different from each other to adjust the pressure required for toner transport and reduce the difference in toner transport force for each color of toner.

[0111] As shown in Figure 14, the toner transport paths Q2Y, Q2M, Q2C, and Q2K are each composed of flexible cylindrical tubes that can be bent. The lengths of the toner transport paths Q2Y, Q2M, Q2C, and Q2K are shorter in the order of Q2Y, Q2M, Q2C, and Q2K. In this embodiment, the inner diameters of the toner transport paths Q2Y, Q2M, Q2C, and Q2K are larger in the order of Q2Y, Q2M, Q2C, and Q2K.

[0112] In other words, if the lengths of the toner transport paths Q2Y, Q2M, Q2C, and Q2K are L2Y, L2M, L2C, and L2K, and the inner diameters of the toner transport paths Q2Y, Q2M, Q2C, and Q2K are D2Y, D2M, D2C, and D2K, then these lengths and inner diameters satisfy the following relationship. L2Y <L2M<L2C<L2K ···(4) D2Y> D2M > D2C > D2K ... (5)

[0113] Furthermore, since the inner circumferential surfaces of the toner transport paths Q2Y, Q2M, Q2C, and Q2K in this embodiment are each circular in shape, the cross-sectional areas A2Y, A2M, A2C, and A2K of the internal space of the toner transport paths Q2Y, Q2M, Q2C, and Q2K satisfy the following relationship. A2Y > A2M > A2C > A2K ... (6)

[0114] As described above, in toner transport paths Q2Y, Q2M, Q2C, and Q2K that extend along the direction of gravity G, the pressure required for toner transport increases as the distance between the toner cartridge C and the process cartridge B increases. Therefore, by reducing the inner diameter (cross-sectional area) of longer toner transport paths Q2Y, Q2M, Q2C, and Q2K, the pressure loss in the toner transport paths Q2Y, Q2M, Q2C, and Q2K can be leveled. This makes it possible to equalize the toner transport force for each color of toner and stabilize the amount of toner transported for each color.

[0115] For example, the length L2K of the toner transport path Q2K, which is the length from the first end EK3 to the second end EK4, is longer than the length L2Y of the toner transport path Q2Y, which is the length from the third end EY3 to the fourth end EY4. In this case, the cross-sectional area A2K of the internal space of the toner transport path Q2K is narrower than the cross-sectional area A2Y of the internal space of the toner transport path Q2Y. This is because the inner diameter D2K of the toner transport path Q2K is smaller than the inner diameter D2Y of the toner transport path Q2Y.

[0116] <Third Embodiment> Next, a third embodiment of the present invention will be described. The third embodiment is a modification of the toner transport path configuration of the first and second embodiments. For this reason, the same configuration as in the first embodiment will be omitted from the illustration or will be described using the same reference numerals in the figures. Figure 15(a) is a cross-sectional view showing a toner transport path with a circular cross-section. Figure 15(b) is a cross-sectional view showing a toner transport path with an elliptical cross-section.

[0117] The toner transport path shown in Figure 15(a) has an inner diameter of 2d, and the toner transport path shown in Figure 15(b) is obtained by compressing the toner transport path with an inner diameter of 2d shown in Figure 15(a) in one direction to create an elliptical shape. In the toner transport path shown in Figure 15(b), the length of the major axis of the elliptical internal space is 2a, and the length of the minor axis is 2b.

[0118] At this time, in order to consider the pressure loss of the toner transport path shown in Figure 15(b), which has an elliptical cross-section, the hydraulic diameter (equivalent diameter) Dh of the circular equivalent of the toner transport path in Figure 15(b) satisfies the following equation. c = (ab) / (a ​​+ b) Dh=4ab / (a+b)(64-16c^2) / (64-3c^4)

[0119] For example, if the toner transport path shown in Figure 15(a), which has a diameter of 4 mm, is modified so that the length of the long axis is 5 mm and the length of the short axis is 3 mm, the hydraulic diameter of the toner transport path shown in Figure 15(b) will be Dh = 3.69 mm. In other words, the cross-sectional area of ​​the internal space of the toner transport path shown in Figure 15(b) is smaller than that of the toner transport path shown in Figure 15(a), which is equivalent to narrowing the inner diameter.

[0120] Therefore, for example, the toner transport path with a perfectly circular cross-section shown in Figure 15(a) can be applied to the toner transport path QK of the first embodiment shown in Figure 12 and the toner transport path Q2Y of the second embodiment shown in Figure 14. At the same time, the toner transport path with an elliptical cross-section shown in Figure 15(b) can be applied to the toner transport path QY of the first embodiment shown in Figure 12 and the toner transport path Q2K of the second embodiment shown in Figure 14. That is, the toner transport paths QK and QY are each composed of flexible tubes having the same inner diameter 2d, and the toner transport path QK is deformed to have a circular cross-section, while the toner transport path QY is deformed to have an elliptical cross-section. Similarly, the toner transport paths Q2K and Q2Y are each composed of flexible tubes having the same inner diameter 2d, and the toner transport path Q2Y is deformed to have a circular cross-section, while the toner transport path Q2K is deformed to have an elliptical cross-section.

[0121] This allows for the standardization of the inner diameter of the toner transport path and the sharing of parts, thereby leveling the pressure loss in the toner transport paths for each color and reducing costs. Furthermore, the elliptical cross-sectional shape of the toner transport path allows for adjustment of the cross-sectional area of ​​the internal space by the degree to which the toner transport path is compressed, enabling the toner transport force of each color to be uniformed easily and inexpensively, and stabilizing the toner transport volume for each color.

[0122] <Fourth Embodiment> Next, a fourth embodiment of the present invention will be described. In the fourth embodiment, the lengths and inner diameters of the toner transport paths QY, QM, QC, and QK of the first embodiment are changed to be the same. For this reason, the same configuration as in the first embodiment will be omitted from the illustration or will be described using the same reference numerals in the illustration.

[0123] Figure 16 is a plan view showing the toner transport paths Q4Y, Q4M, Q4C, and Q4K according to the fourth embodiment. The toner transport paths Q4Y, Q4M, Q4C, and Q4K in this embodiment extend horizontally, similar to the first embodiment. Furthermore, the toner transport paths Q4Y, Q4M, Q4C, and Q4K are each composed of tubes having the same inner diameter.

[0124] The toner transport path Q4K, which serves as the first tube connecting the toner cartridge CK and the developing container 12K, is connected to the developing container 12K at point RK. The toner transport path Q4C, which connects the toner cartridge CC and the developing container 12C, is connected to the developing container 12C at point RC. The toner transport path Q4M, which connects the toner cartridge CM and the developing container 12M, is connected to the developing container 12M at point RM. The toner transport path Q4Y, which serves as the second tube connecting the toner cartridge CY and the developing container 12Y, is connected to the developing container 12Y at point RY.

[0125] In this embodiment, the developing containers 12Y, 12M, 12C, and 12K are arranged in the X direction at intervals of L6, and the toner cartridges CY, CM, CC, and CK are arranged in the Z direction at intervals of L5. Each developing container 12Y, 12M, 12C, and 12K has one end portion 12Ya, 12Ma, 12Ca, and 12Ka in the Z direction, and the other end portion 12Yb, 12Mb, 12Cb, and 12Kb. Position D1 is defined as a predetermined distance downstream in the Z direction from the one end portion 12Ya, 12Ma, 12Ca, and position D2 is defined as a predetermined distance upstream in the Z direction from the other end portion 12Yb, 12Mb, 12Cb, and 12Kb. In other words, positions D1 and D2 are located at the same distance from one end (12Ya, 12Ma, 12Ca, 12Ka) and the other end (12Yb, 12Mb, 12Cb, 12Kb), respectively.

[0126] In this embodiment, in order to equalize the pressure loss in the toner transport paths Q4Y, Q4M, Q4C, and Q4K, the total lengths of the toner transport paths Q4Y, Q4M, Q4C, and Q4K are configured to be equal to each other. Therefore, point RK is located at the same position as position D1 in the Z direction, and point RC is located downstream of position D1 by a distance (L6-L5) in the Z direction. Point RM is located upstream of position D2 by a distance (2×L6-L5) in the Z direction, and point RY is located upstream of position D2 by a distance (3×L6) in the Z direction.

[0127] Furthermore, in this embodiment, the toner transport paths Q4C and Q4K are arranged so that, when viewed in the direction of gravity (-Y direction), they pass through one end 12Ca and 12Ka, respectively. The toner transport paths Q4Y and Q4M are arranged so that, when viewed in the direction of gravity (-Y direction), they pass through the other end 12Yb and 12Mb, respectively. This allows the toner transport paths Q4Y, Q4M, Q4C, and Q4K to be arranged compactly, and by suppressing the total length of the toner transport paths Q4Y, Q4M, Q4C, and Q4K, the pump unit 135 can be miniaturized.

[0128] By arranging the toner transport paths Q4Y, Q4M, Q4C, and Q4K in this manner, the total lengths of the toner transport paths Q4Y, Q4M, Q4C, and Q4K can be made equal. Therefore, the pressure loss in the toner transport paths Q4Y, Q4M, Q4C, and Q4K can be equalized. As a result, the toner transport force for each color of toner can be made uniform, and the amount of toner transported for each color can be stabilized.

[0129] This allows the same type of pump to be used for the four pumps 35 that transport the four colors of toner, and these pumps can be properly controlled by the same pump drive unit (36Y, etc.). In addition, since common parts can be used for the toner transport paths Q4Y, Q4M, Q4C, and Q4K, costs can be reduced, and assembly errors when assembling the toner transport paths Q4Y, Q4M, Q4C, and Q4K can be reduced.

[0130] <Fifth Embodiment> Next, a fifth embodiment of the present invention will be described. The fifth embodiment is a modification of the arrangement of the toner transport paths Q4Y, Q4M, Q4C, and Q4K in the fourth embodiment. For this reason, the same configuration as in the fourth embodiment will be omitted from the illustration or will be described using the same reference numerals in the illustration.

[0131] Figure 17 is a plan view showing the toner transport paths Q5Y, Q5M, Q5C, and Q5K according to the fifth embodiment. The toner transport paths Q5Y, Q5M, Q5C, and Q5K in this embodiment extend horizontally, similar to the first and fourth embodiments. Furthermore, the toner transport paths Q5Y, Q5M, Q5C, and Q5K are each composed of tubes having the same inner diameter.

[0132] The toner transport path Q5K, which serves as the first tube connecting toner cartridge CK and developer container 12K, is connected to developer container 12K at point R5K. The toner transport path Q5C, which connects toner cartridge CC and developer container 12C, is connected to developer container 12C at point R5C. The toner transport path Q5M, which serves as the second tube connecting toner cartridge CM and developer container 12M, is connected to developer container 12M at point R5M. The toner transport path Q5Y, which connects toner cartridge CY and developer container 12Y, is connected to developer container 12Y at point R5Y.

[0133] In this embodiment, as in the fourth embodiment, the total lengths of the toner transport paths Q5Y, Q5M, Q5C, and Q5K are configured to be equal in order to equalize the pressure loss in the toner transport paths Q5Y, Q5M, Q5C, and Q5K. Therefore, point R5K is located downstream of position D1 by a distance of (3 × L5) in the Z direction, and point R5C is located downstream of position D1 by a distance of (2 × L5 + L6) in the Z direction. Point R5M is located downstream of position D1 by a distance of (2 × L6 + L5) in the Z direction, and point R5Y is located downstream of position D1 by a distance of (3 × L6) in the Z direction.

[0134] Furthermore, in this embodiment, the toner transport paths Q5Y, Q5M, Q5C, and Q5K are arranged so that they pass through one end 12Ya, 12Ma, 12Ca, and 12Ka, respectively, when viewed in the direction of gravity (-Y direction). This allows the toner transport paths Q5Y, Q5M, Q5C, and Q5K to be assembled and maintained from one end of the developing containers 12Y, 12M, 12C, and 12K, thereby improving work efficiency.

[0135] By arranging the toner transport paths Q5Y, Q5M, Q5C, and Q5K in this manner, the total lengths of the toner transport paths Q5Y, Q5M, Q5C, and Q5K can be made equal. Therefore, the pressure loss in the toner transport paths Q5Y, Q5M, Q5C, and Q5K can be equalized. As a result, the toner transport force for each color of toner can be made uniform, and the amount of toner transported for each color can be stabilized.

[0136] This allows the same type of pump to be used for the four pumps 35 that transport the four colors of toner, and these pumps can be properly controlled by the same pump drive unit (36Y, etc.). In addition, since common parts can be used for the toner transport paths Q5Y, Q5M, Q5C, and Q5K, costs can be reduced, and assembly errors when assembling the toner transport paths Q5Y, Q5M, Q5C, and Q5K can be reduced.

[0137] <Sixth Embodiment> Next, a sixth embodiment of the present invention will be described. The sixth embodiment is a modification of the shapes of the toner transport paths Q2Y, Q2M, Q2C, and Q2K of the second embodiment. For this reason, the same configuration as in the second embodiment will be omitted from the illustration or will be described using the same reference numerals in the illustration. In particular, the toner transport path Q6Y, which connects the toner cartridge CY as a cartridge to the developing container 122Y of the process cartridge BY, will be described below. Note that the other toner transport paths Q6M, Q6C, and Q6K connected to toner cartridges CM, CC, and CK may have the same configuration as the toner transport path Q6Y.

[0138] Figure 18(a) is a schematic diagram showing a toner transport path Q7Y as a comparative example. Figure 18(b) is a schematic diagram showing a toner transport path Q6Y according to the sixth embodiment. As shown in Figures 18(a) and (b), the developer container 122Y of the process cartridge BY is located above the toner cartridge C. As shown in Figure 18(a), the toner transport path Q7Y according to the comparative example connects the toner cartridge CY and the developer container 122Y, and has a first horizontal section 81, a vertical section 82, a second horizontal section 83, an upward bent section 84, and a horizontal bent section 85.

[0139] The first horizontal section 81 and the second horizontal section 83 extend horizontally, for example, in the X direction. The vertical section 82 extends vertically, i.e., in the Y direction. The upward bend section 84 is provided between the first horizontal section 81 and the vertical section 82 and bends the toner transport path Q7Y upward. The horizontal bend section 85 is provided between the vertical section 82 and the second horizontal section 83 and bends the toner transport path Q7Y horizontally, for example, upstream in the X direction.

[0140] After the toner T is transported from the toner cartridge CY shown in Figure 18(a) to the developing container 122Y of the process cartridge BY via the toner transport path Q7Y, the pump 35Y stops, and toner T remains in the toner transport path Q7Y. In particular, the toner T accumulates in the lower part of the vertical section 82, i.e., the upper bent section 84, due to gravity. Also, the toner T in the first horizontal section 81 and the second horizontal section 83 accumulates in place.

[0141] Next, when the pump 35Y is restarted and air is supplied to the toner transport path Q7Y again, the air is first supplied to the toner T accumulated in the upper bend 84. Then, as the air and toner T gradually mix, the bulk density of the toner T decreases, and the toner T is transported together with the air to the developing container 122Y of the process cartridge BY. Here, if the amount of toner T accumulated in the upper bend 84 in the comparative example is amount V, then the maximum pressure required for toner transport in the toner transport path Q7Y is pressure P1.

[0142] On the other hand, as shown in Figure 18(b), the toner transport path Q6Y according to this embodiment has a first end EY5 that communicates with the inside of the toner cartridge CY and a second end EY6 that communicates with the toner storage section of the developing container 122Y, and extends from the first end EY5 to the second end EY6. The toner transport path Q6Y also has a first horizontal section 91, a first vertical section 92, a second horizontal section 93, a second vertical section 94, a third horizontal section 95, a first upward bend section 96, a first horizontal bend section 97, a second upward bend section 98, and a second horizontal bend section 99.

[0143] The first horizontal section 91, the second horizontal section 93, and the third horizontal section 95 extend horizontally, for example, in the X direction. The first vertical section 92 and the second vertical section 94 extend vertically, i.e., in the Y direction. The first horizontal section 91, as a fourth section, is provided between the first end EY5 and the first vertical section 92. The first vertical section 92, as a first section, is provided between the first horizontal section 91 and the second horizontal section 93. The second horizontal section 93, as a third section, is provided between the first vertical section 92 and the second vertical section 94. The third horizontal section 95, as a fifth section, is provided between the second vertical section 94 and the second end EY6. In this embodiment, the lengths of the first vertical section 92 and the second vertical section 94 are each shorter than the length of the second horizontal section 93.

[0144] The first upward bend 96, which serves as the first bend, is provided between the first horizontal section 91 and the first vertical section 92, and bends the toner transport path Q6Y, which serves as the tube, upward. The first horizontal bend 97 is provided between the first vertical section 92 and the second horizontal section 93, and bends the toner transport path Q6Y horizontally, for example, upstream in the X direction. The second upward bend 98, which serves as the second bend, differs from the first upward bend 96 in that it is provided between the second horizontal section 93 and the second vertical section 94, and bends the toner transport path Q6Y upward. The second horizontal bend 99 is provided between the second vertical section 94 and the third horizontal section 95, and bends the toner transport path Q6Y horizontally, for example, upstream in the X direction.

[0145] In this embodiment, the first vertical section 92 and the second vertical section 94 extended in the vertical direction, but this is not limited to this. For example, the first vertical section 92 and the second vertical section 94 may be provided to extend at an inclination angle greater than 60 degrees with respect to the horizontal direction. Also, in this embodiment, the first horizontal section 91, the second horizontal section 93 and the third horizontal section 95 extended in the horizontal direction, but this is not limited to this. For example, the first horizontal section 91, the second horizontal section 93 and the third horizontal section 95 may be provided to extend in the horizontal direction, a downward inclination direction, or an upward inclination direction of 15 degrees or less with respect to the horizontal direction in the direction in which the toner is transported.

[0146] After the toner T is transported from the toner cartridge CY to the developing container 122Y of the process cartridge BY via the toner transport path Q6Y as shown in Figure 18(b), the pump 35Y stops, and toner T remains in the toner transport path Q6Y. In particular, the toner T accumulates due to gravity in the lower parts of the first vertical section 92 and the second vertical section 94, i.e., the first upward bend section 96 and the second upward bend section 98. In addition, the toner T in the first horizontal section 91, the second horizontal section 93 and the third horizontal section 95 accumulates in place.

[0147] Next, when the pump 35Y is restarted and air is supplied to the toner transport path Q6Y again, the air is first supplied to the toner T accumulated in the first upper bend 96. Then, as the air and toner T gradually mix, the bulk density of the toner T decreases. Next, air is supplied to the toner T accumulated in the second upper bend 98, and the toner T is transported together with the air to the developing container 122Y of the process cartridge BY.

[0148] In this embodiment, the toner transport path Q6Y has a first upper bend 96 and a second upper bend 98. The amount of toner T accumulated in the first upper bend 96 and the second upper bend 98 is half the amount of toner T V accumulated in the upper bend 84 of the toner transport path Q7Y in the comparative example (V / 2). The maximum pressure required for toner transport in the toner transport path Q6Y is proportional to the amount of toner T accumulated in one place. Therefore, in the toner transport path Q6Y provided with two upper bends (96, 98) as in this embodiment, the maximum pressure required for toner transport is pressure (P1 / 2).

[0149] For example, when air is supplied from the pump 35 to the toner cartridge C and the pressure in the first horizontal section 91 rises to pressure (P1 / 2), the toner T accumulated in the first upper bend section 96 is transported, and the pressure in the toner transport path Q6Y decreases. Then, when the air reaches the second upper bend section 98, the pressure in the second horizontal section 93 rises again to pressure (P1 / 2). As a result, the toner T accumulated in the second upper bend section 98 is transported, and the pressure in the toner transport path Q6Y decreases. By providing multiple bends (96, 98) in the toner transport path Q6Y in this way, the toner T accumulated in the bends (96, 98) is gradually loosened while being transported.

[0150] In particular, in this embodiment, two upward bends (96, 98) are provided so that the height H1 of the toner transport path Q6Y is divided equally. In other words, the length of the first vertical section 92 and the second vertical section 94 in the vertical direction (Y direction) is H1 / 2, which is half the height H1 of the toner transport path Q6Y in the vertical direction. By providing two upward bends (96, 98) so that the height H1 of the toner transport path Q6Y is divided equally, the maximum pressure required for toner transport can be further reduced. This makes it possible to reduce the capacity and size of the pump 35.

[0151] In this embodiment, the case with two upward bends (96, 98) was described as an example, but the invention is not limited to this. For example, the number of upward bends provided in the toner transport path Q6Y may be three or more. By increasing the number of upward bends in this way, the amount of toner accumulated in each upward bend can be reduced, and the maximum pressure required for toner transport can be further reduced.

[0152] On the other hand, increasing the number of upward bends can lengthen the toner transport path, leading to increased pressure loss in the steady state. Therefore, it is desirable to determine the number of upward bends within an appropriate range according to the characteristics of the pump 35.

[0153] <Other Embodiments> In addition, although the configuration of the toner cartridge that can be attached to the main body 100 has been described in all of the above-described forms, the present invention is not limited to these. The present invention can also be applied to all-in-one cartridges that integrate the toner cartridge C and the process cartridge B, or cartridges that integrate the toner cartridge C and the developing means, and the same effects as described above can be obtained.

[0154] Furthermore, although the discharge port 16a and discharge pipe 27 were provided in the toner chamber 16 in all of the above-described configurations, the system is not limited to this. For example, the discharge port 16a may be provided in the air chamber 17, the discharge pipe 27 may pass through a hole provided in the filter 18, and the inlet 27a may face the lowest part 18b of the filter 18 while the outlet 27b is connected to the discharge port 16a.

[0155] Summary of this disclosure This disclosure includes at least the following: (Composition 1) An image forming apparatus, A first cartridge containing the first toner, A second cartridge containing the second toner, A device body on which the first cartridge and the second cartridge can be attached and detached, The pump section that discharges air, A first developing container including a first toner storage section for storing the first toner, A second developing container including a second toner storage section for storing the second toner, A first tube having a first end communicating with the inside of the first cartridge and a second end communicating with the inside of the first toner storage section, extending from the first end to the second end and through which the first toner passes, A second tube having a third end communicating with the inside of the second cartridge and a fourth end communicating with the inside of the first toner storage section, extending from the third end to the fourth end and through which the second toner passes, The device comprises a main body having, The first cartridge is, The first toner chamber, which houses the previous first toner, A first filter configured to obstruct the passage of the first toner and to allow the passage of air, A first air chamber adjacent to the first toner chamber via the first filter, the first air chamber having a first intake for taking in air discharged from the pump unit, A first discharge port for discharging the first toner contained in the first toner chamber to the outside of the first cartridge, It has a first pipe configured to communicate with the first discharge port, through which the first toner discharged from the first discharge port passes, The aforementioned second cartridge is A second toner chamber containing the adjacent second toner, A second filter configured to obstruct the passage of the second toner and to allow the passage of air, A second air chamber adjacent to the second toner chamber via the second filter, the second air chamber having a second intake for taking in air discharged from the pump section, A second outlet for discharging the second toner contained in the second toner chamber to the outside of the second cartridge, It has a second pipe configured to communicate with the second discharge port, through which the second toner discharged from the second discharge port passes, The first cartridge is configured such that the first toner in the first toner chamber is discharged from the first outlet and transported to the first toner storage section via the first tube by air taken in from the first intake port of the first cartridge. The air taken in from the second intake port of the second cartridge causes the second toner in the second toner chamber to be discharged from the second outlet port and transported to the second toner storage section via the second tube. A portion of the first tube that is longer than half the length from the first end to the second end is provided to extend horizontally, downwards, or upwards at an angle of 45 degrees or less relative to the horizontal direction in the direction in which the first toner is conveyed. The portion of the second tube that is longer than half of the length from the third end to the fourth end is provided to extend in the horizontal direction, the downward inclined direction, or the upward inclined direction of 45 degrees or less with respect to the horizontal direction, in the direction in which the second toner is conveyed. The length of the first tube from the first end to the second end is longer than the length of the second tube from the third end to the fourth end. The cross-sectional area of ​​the internal space of the first tube is larger than the cross-sectional area of ​​the internal space of the second tube. An image forming apparatus characterized by the following: (Configuration 2) The first tube and the second tube are each cylindrical tubes, The inner diameter of the first tube is larger than the inner diameter of the second tube. The image forming apparatus according to configuration 1, characterized in that it is a picture forming apparatus. (Composition 3) The first tube and the second tube are both flexible tubes having the same inner diameter and being bendable. The first tube has a circular cross-section, The second tube is deformed so that its cross-section is elliptical. The image forming apparatus according to configuration 1, characterized in that it is a picture forming apparatus. (Composition 4) The main body of the device has a control unit that controls the pump section, The pump unit comprises a first pump that discharges air for intake into the first intake of the first air chamber, and a second pump that discharges air for intake into the second intake of the second air chamber. The control unit is capable of independently controlling the drive of the first pump and the second pump. An image forming apparatus according to any one of configurations 1 to 3, characterized by the above. (Composition 5) The first discharge port and the first pipe are provided in the first toner chamber. The end of the first pipe opposite to the end connected to the outlet is configured to open toward the first filter. The second discharge port and the second pipe are provided in the second toner chamber. The end of the second pipe opposite to the end connected to the outlet is configured to open toward the second filter. An image forming apparatus according to any one of configurations 1 to 4, characterized by the above. (Composition 6) An image forming apparatus, A first cartridge containing the first toner, A second cartridge containing the second toner, A device body on which the first cartridge and the second cartridge can be attached and detached, The pump section that discharges air, A first developing container including a first toner storage section for storing the first toner, A second developing container including a second toner storage section for storing the second toner, A first tube having a first end communicating with the inside of the first cartridge and a second end communicating with the inside of the first toner storage section, extending from the first end to the second end and through which the first toner passes, A second tube having a third end communicating with the inside of the second cartridge and a fourth end communicating with the inside of the first toner storage section, extending from the third end to the fourth end and through which the second toner passes, The device comprises a main body having, The first cartridge is, The first toner chamber, which houses the previous first toner, A first filter configured to obstruct the passage of the first toner and to allow the passage of air, A first air chamber adjacent to the first toner chamber via the first filter, the first air chamber having a first intake for taking in air discharged from the pump unit, A first discharge port for discharging the first toner contained in the first toner chamber to the outside of the first cartridge, It has a first pipe configured to communicate with the first discharge port, through which the first toner discharged from the first discharge port passes, The aforementioned second cartridge is A second toner chamber containing the adjacent second toner, A second filter configured to obstruct the passage of the second toner and to allow the passage of air, A second air chamber adjacent to the second toner chamber via the second filter, the second air chamber having a second intake for taking in air discharged from the pump section, A second outlet for discharging the second toner contained in the second toner chamber to the outside of the second cartridge, It has a second pipe configured to communicate with the second discharge port, through which the second toner discharged from the second discharge port passes, The first cartridge is configured such that the first toner in the first toner chamber is discharged from the first outlet and transported to the first toner storage section via the first tube by air taken in from the first intake port of the first cartridge. The air taken in from the second intake port of the second cartridge causes the second toner in the second toner chamber to be discharged from the second outlet port and transported to the second toner storage section via the second tube. A portion of the first tube that is longer than half the length from the first end to the second end is provided such that, in the direction in which the first toner is conveyed, it extends upward in the opposite direction to gravity, in an upward inclined direction, or in a downward inclined direction of 45 degrees or less with respect to the horizontal direction. The portion of the second tube that is longer than half the length from the third end to the fourth end is provided so as to extend in the direction in which the second toner is conveyed, in the upward direction or the upward inclined direction or in the downward inclined direction of 45 degrees or less with respect to the horizontal direction, The length of the first tube from the first end to the second end is longer than the length of the second tube from the third end to the fourth end. The cross-sectional area of ​​the internal space of the first tube is narrower than the cross-sectional area of ​​the internal space of the second tube. An image forming apparatus characterized by the following: (Composition 7) The first tube and the second tube are each cylindrical tubes, The inner diameter of the first tube is smaller than the inner diameter of the second tube. The image forming apparatus according to configuration 6, characterized by the features described therein. (Composition 8) The first tube and the second tube are both flexible tubes having the same inner diameter and being bendable. The second tube has a circular cross-section. The first tube is deformed so that its cross-section is elliptical. The image forming apparatus according to configuration 6, characterized by the features described therein. (Composition 9) The main body of the device has a control unit that controls the pump section, The pump unit comprises a first pump that discharges air for intake into the first intake of the first air chamber, and a second pump that discharges air for intake into the second intake of the second air chamber. The control unit is capable of independently controlling the drive of the first pump and the second pump. An image forming apparatus according to any one of configurations 6 to 8, characterized by the above. (Composition 10) The first discharge port and the first pipe are provided in the first toner chamber. The end of the first pipe opposite to the end connected to the outlet is configured to open toward the first filter. The second discharge port and the second pipe are provided in the second toner chamber. The end of the second pipe opposite to the end connected to the outlet is configured to open toward the second filter. An image forming apparatus according to any one of configurations 6 to 9 characterized by the above. (Composition 11) An image forming apparatus, A first cartridge containing the first toner, A second cartridge containing the second toner, A device body on which the first cartridge and the second cartridge can be attached and detached, The pump section that discharges air, A first developing container including a first toner storage section for storing the first toner, A second developing container including a second toner storage section for storing the second toner, A first tube having a first end communicating with the inside of the first cartridge and a second end communicating with the inside of the first toner storage section, extending from the first end to the second end and through which the first toner passes, A second tube having a third end communicating with the inside of the second cartridge and a fourth end communicating with the inside of the first toner storage section, extending from the third end to the fourth end and through which the second toner passes, The device comprises a main body having, The first cartridge is, The first toner chamber, which houses the previous first toner, A first filter configured to obstruct the passage of the first toner and to allow the passage of air, A first air chamber adjacent to the first toner chamber via the first filter, the first air chamber having a first intake for taking in air discharged from the pump unit, A first discharge port for discharging the first toner contained in the first toner chamber to the outside of the first cartridge, It has a first pipe configured to communicate with the first discharge port, through which the first toner discharged from the first discharge port passes, The aforementioned second cartridge is A second toner chamber containing the adjacent second toner, A second filter configured to obstruct the passage of the second toner and to allow the passage of air, A second air chamber adjacent to the second toner chamber via the second filter, the second air chamber having a second intake for taking in air discharged from the pump section, A second outlet for discharging the second toner contained in the second toner chamber to the outside of the second cartridge, It has a second pipe configured to communicate with the second discharge port, through which the second toner discharged from the second discharge port passes, The first cartridge is configured such that the first toner in the first toner chamber is discharged from the first outlet and transported to the first toner storage section via the first tube by air taken in from the first intake port of the first cartridge. The air taken in from the second intake port of the second cartridge causes the second toner in the second toner chamber to be discharged from the second outlet port and transported to the second toner storage section via the second tube. The total length of the first tube is equal to the total length of the second tube. An image forming apparatus characterized by the following: (Composition 12) The first tube and the second tube are tubes having the same inner diameter. The image forming apparatus according to configuration 11, characterized by the features described above. (Composition 13) The first developing container and the second developing container each extend in a longitudinal direction along the horizontal direction, and each has one end and the other end, The first tube is positioned such that, when viewed in the direction of gravity, it passes through one end of the first developing container in the longitudinal direction, The second tube is positioned such that, when viewed in the direction of gravity, it passes through the other end of the second developing container in the longitudinal direction. The image forming apparatus according to configuration 11, characterized by the features described above. (Composition 14) The first developing container and the second developing container each extend in a longitudinal direction along the horizontal direction, and each has one end and the other end, The first tube is positioned such that, when viewed in the direction of gravity, it passes through one end of the first developing container in the longitudinal direction, The second tube is positioned such that, when viewed in the direction of gravity, it passes through one end of the second developing container in the longitudinal direction. The image forming apparatus according to configuration 11, characterized by the features described above. (Composition 15) The main body of the device has a control unit that controls the pump section, The pump unit comprises a first pump that discharges air for intake into the first intake of the first air chamber, and a second pump that discharges air for intake into the second intake of the second air chamber. The control unit is capable of independently controlling the drive of the first pump and the second pump. An image forming apparatus according to any one of configurations 11 to 14, characterized by the above. (Composition 16) The first discharge port and the first pipe are provided in the first toner chamber. The end of the first pipe opposite to the end connected to the outlet is configured to open toward the first filter. The second discharge port and the second pipe are provided in the second toner chamber. The end of the second pipe opposite to the end connected to the outlet is configured to open toward the second filter. An image forming apparatus according to any one of configurations 11 to 15, characterized by the above. (Composition 17) An image forming apparatus, A cartridge that contains toner, The device body, which allows the aforementioned cartridge to be attached and detached, The pump section that discharges air, A developing container including a toner storage section for storing the toner, the developing container being positioned above the cartridge, A tube having a first end communicating with the inside of the cartridge and a second end communicating with the inside of the toner storage section, extending from the first end to the second end and through which the toner passes, The device comprises a main body having, The aforementioned cartridge is A toner chamber for storing the aforementioned toner, A filter configured to obstruct the passage of the toner and allow the passage of air, An air chamber adjacent to the toner chamber via the aforementioned filter, the air chamber having an intake for taking in air discharged from the pump section, An outlet for discharging the toner contained in the toner chamber to the outside of the cartridge, It has a pipe configured to communicate with the aforementioned discharge port, through which the toner discharged from the discharge port passes, The toner in the toner chamber is discharged from the outlet and transported to the toner storage section via the tube by air taken in from the intake port of the cartridge. The tube includes, in the direction in which the toner is transported, a first portion and a second portion extending between the first and second ends at an inclination angle greater than 60 degrees with respect to the vertical or horizontal direction, and a third portion extending between the first and second portions in the horizontal, downward, or upward direction with respect to the horizontal at an inclination of 15 degrees or less. An image forming apparatus characterized by the following: (Composition 18) The length of the first portion of the tube is shorter than the length of the third portion. The image forming apparatus according to configuration 17, characterized by the features described above. (Composition 19) The length of the second portion of the tube is shorter than the length of the third portion. The image forming apparatus according to configuration 18, characterized by the features described above. (Composition 20) The first and second parts extend vertically. The image forming apparatus according to configuration 17 or 18, characterized by the above. (Composition 21) The tube includes, in the direction in which the toner is transported, a fourth portion provided between the first end and the first portion and extending in the horizontal direction, a downward sloping direction, or an upward sloping direction of 15 degrees or less with respect to the horizontal direction, and a fifth portion provided between the second portion and the second end and extending in the horizontal direction, a downward sloping direction, or an upward sloping direction of 15 degrees or less with respect to the horizontal direction. An image forming apparatus according to any one of configurations 17 to 20, characterized by the above. (Composition 22) The lengths of the first and second portions in the vertical direction are each half the length of the tube in the vertical direction. An image forming apparatus according to any one of the configurations 17 to 21 characterized by the above. [Explanation of Symbols]

[0156] 12a: First toner storage section, second toner storage section (toner storage section) / 12K: First developing container (developing container) / 12Ka, 12Ya: One end / 12Y: Second developing container (developing container) / 12Kb, 12Yb: The other end / 16: First toner chamber, second toner chamber (toner chamber) / 16a: First discharge port, second discharge port (discharge port) / 17: First air chamber, second air chamber (air chamber) / 18: First filter, second filter (filter) / 20: First intake port, second intake port (intake port) / 27: First pipe, second pipe, pipe (discharge pipe) / 27a: End (entrance) / 27b: End (exit) / 35K: First pump (pump) / 35Y: Second pump (pump) / 40: Control unit / 91: Fourth part (first horizontal part) / 92: First part (first vertical part) / 93: Third part (second horizontal part) / 94: Second part (second vertical part) / 95: Fifth part (third horizontal part) / 100: Apparatus main body / 122Y: Developing container / 135: Pump section / A1K, A2K, A1Y, A2Y: Cross-sectional area / CK: First cartridge, cartridge (toner cartridge) / CY: Second cartridge (toner cartridge) / D1K, D2K, D1Y, D2Y: Inner diameter / EK1, EK3, EY5: First end / EK2, EK4: Second end / EY1, EY3, EY6: Third end / EY2, EY4: Fourth end / G: Direction of gravity / IF: Image forming apparatus / QK, Q2K, Q4K, Q5K: First tube (toner conveyance path) / QY, Q2Y, Q4Y, Q5Y: Second tube (toner conveyance path) / Q6Y: Tube (toner conveyance path) / Y: Longitudinal direction (direction)

Claims

1. An image forming apparatus, A first cartridge containing the first toner, A second cartridge containing the second toner, A device body on which the first cartridge and the second cartridge can be attached and detached, The pump section that discharges air, A first developing container including a first toner storage section for storing the first toner, A second developing container including a second toner storage section for storing the second toner, A first tube having a first end communicating with the inside of the first cartridge and a second end communicating with the inside of the first toner storage section, extending from the first end to the second end and through which the first toner passes, A second tube having a third end communicating with the inside of the second cartridge and a fourth end communicating with the inside of the first toner storage section, extending from the third end to the fourth end and through which the second toner passes, The device comprises a main body having, The first cartridge is, A first toner chamber containing the first toner, A first filter configured to obstruct the passage of the first toner and to allow the passage of air, A first air chamber adjacent to the first toner chamber via the first filter, the first air chamber having a first intake for taking in air discharged from the pump section, A first discharge port for discharging the first toner contained in the first toner chamber to the outside of the first cartridge, It has a first pipe configured to communicate with the first discharge port, through which the first toner discharged from the first discharge port passes, The aforementioned second cartridge is The second toner chamber containing the second toner, A second filter configured to obstruct the passage of the second toner and to allow the passage of air, A second air chamber adjacent to the second toner chamber via the second filter, the second air chamber having a second intake for taking in air discharged from the pump section, A second outlet for discharging the second toner contained in the second toner chamber to the outside of the second cartridge, It has a second pipe configured to communicate with the second discharge port, through which the second toner discharged from the second discharge port passes, The first toner in the first toner chamber is discharged from the first outlet and transported to the first toner storage section via the first tube by air taken in from the first intake port of the first cartridge. The air taken in from the second intake port of the second cartridge causes the second toner in the second toner chamber to be discharged from the second outlet port and transported to the second toner storage section via the second tube. A portion of the first tube that is longer than half the length from the first end to the second end is provided to extend horizontally, downwards, or upwards at an angle of 45 degrees or less relative to the horizontal direction in the direction in which the first toner is conveyed. The portion of the second tube that is longer than half the length from the third end to the fourth end is provided to extend in the horizontal direction, the downward inclined direction, or the upward inclined direction of 45 degrees or less with respect to the horizontal direction, in the direction in which the second toner is conveyed. The length of the first tube from the first end to the second end is longer than the length of the second tube from the third end to the fourth end. The cross-sectional area of ​​the internal space of the first tube is larger than the cross-sectional area of ​​the internal space of the second tube. An image forming apparatus characterized by the following features.

2. The first tube and the second tube are each cylindrical tubes, The inner diameter of the first tube is larger than the inner diameter of the second tube. The image forming apparatus according to feature 1.

3. The first tube and the second tube are both flexible tubes having the same inner diameter and being bendable. The first tube has a circular cross-section, The second tube is deformed so that its cross-section is elliptical. The image forming apparatus according to feature 1.

4. The main body of the device has a control unit that controls the pump section, The pump section comprises a first pump that discharges air for intake into the first intake of the first air chamber, and a second pump that discharges air for intake into the second intake of the second air chamber. The control unit is capable of independently controlling the drive of the first pump and the second pump. The image forming apparatus according to feature 1.

5. The first discharge port and the first pipe are provided in the first toner chamber. The end of the first pipe opposite to the end connected to the outlet is configured to open toward the first filter. The second discharge port and the second pipe are provided in the second toner chamber. The end of the second pipe opposite to the end connected to the outlet is configured to open toward the second filter. The image forming apparatus according to feature 1.

6. An image forming apparatus, A first cartridge containing the first toner, A second cartridge containing the second toner, A device body on which the first cartridge and the second cartridge can be attached and detached, The pump section that discharges air, A first developing container including a first toner storage section for storing the first toner, A second developing container including a second toner storage section for storing the second toner, A first tube having a first end communicating with the inside of the first cartridge and a second end communicating with the inside of the first toner storage section, extending from the first end to the second end and through which the first toner passes, A second tube having a third end communicating with the inside of the second cartridge and a fourth end communicating with the inside of the first toner storage section, extending from the third end to the fourth end and through which the second toner passes, The device comprises a main body having, The first cartridge is, A first toner chamber containing the first toner, A first filter configured to obstruct the passage of the first toner and to allow the passage of air, A first air chamber adjacent to the first toner chamber via the first filter, the first air chamber having a first intake for taking in air discharged from the pump section, A first discharge port for discharging the first toner contained in the first toner chamber to the outside of the first cartridge, It has a first pipe configured to communicate with the first discharge port, through which the first toner discharged from the first discharge port passes, The aforementioned second cartridge is The second toner chamber containing the second toner, A second filter configured to obstruct the passage of the second toner and to allow the passage of air, A second air chamber adjacent to the second toner chamber via the second filter, the second air chamber having a second intake for taking in air discharged from the pump section, A second outlet for discharging the second toner contained in the second toner chamber to the outside of the second cartridge, It has a second pipe configured to communicate with the second discharge port, through which the second toner discharged from the second discharge port passes, The first toner in the first toner chamber is discharged from the first outlet and transported to the first toner storage section via the first tube by air taken in from the first intake port of the first cartridge. The air taken in from the second intake port of the second cartridge causes the second toner in the second toner chamber to be discharged from the second outlet port and transported to the second toner storage section via the second tube. The portion of the first tube that is longer than half the length from the first end to the second end is provided so as to extend upward in the direction opposite to the direction of gravity, or in an upward inclined direction, or in a downward inclined direction of 45 degrees or less with respect to the horizontal direction, in the direction in which the first toner is conveyed. The portion of the second tube that is longer than half of the length from the third end to the fourth end is provided so as to extend in the direction in which the second toner is conveyed, in the upward direction or the upward inclined direction or in the downward inclined direction of 45 degrees or less with respect to the horizontal direction, The length of the first tube from the first end to the second end is longer than the length of the second tube from the third end to the fourth end. The cross-sectional area of ​​the internal space of the first tube is smaller than the cross-sectional area of ​​the internal space of the second tube. An image forming apparatus characterized by the following features.

7. The first tube and the second tube are each cylindrical tubes, The inner diameter of the first tube is smaller than the inner diameter of the second tube. The image forming apparatus according to feature 6.

8. The first tube and the second tube are both flexible tubes having the same inner diameter and being bendable. The second tube has a circular cross-section, The first tube is deformed so that its cross-section is elliptical. The image forming apparatus according to feature 6.

9. The main body of the device has a control unit that controls the pump section, The pump section comprises a first pump that discharges air for intake into the first intake of the first air chamber, and a second pump that discharges air for intake into the second intake of the second air chamber. The control unit is capable of independently controlling the drive of the first pump and the second pump. The image forming apparatus according to feature 6.

10. The first discharge port and the first pipe are provided in the first toner chamber. The end of the first pipe opposite to the end connected to the outlet is configured to open toward the first filter. The second discharge port and the second pipe are provided in the second toner chamber. The end of the second pipe opposite to the end connected to the outlet is configured to open toward the second filter. The image forming apparatus according to feature 6.

11. An image forming apparatus, A first cartridge containing the first toner, A second cartridge containing the second toner, A device body on which the first cartridge and the second cartridge can be attached and detached, The pump section that discharges air, A first developing container including a first toner storage section for storing the first toner, A second developing container including a second toner storage section for storing the second toner, A first tube having a first end communicating with the inside of the first cartridge and a second end communicating with the inside of the first toner storage section, extending from the first end to the second end and through which the first toner passes, A second tube having a third end communicating with the inside of the second cartridge and a fourth end communicating with the inside of the first toner storage section, extending from the third end to the fourth end and through which the second toner passes, The device comprises a main body having, The first cartridge is, A first toner chamber containing the first toner, A first filter configured to obstruct the passage of the first toner and to allow the passage of air, A first air chamber adjacent to the first toner chamber via the first filter, the first air chamber having a first intake for taking in air discharged from the pump section, A first discharge port for discharging the first toner contained in the first toner chamber to the outside of the first cartridge, It has a first pipe configured to communicate with the first discharge port, through which the first toner discharged from the first discharge port passes, The aforementioned second cartridge is The second toner chamber containing the second toner, A second filter configured to obstruct the passage of the second toner and to allow the passage of air, A second air chamber adjacent to the second toner chamber via the second filter, the second air chamber having a second intake for taking in air discharged from the pump section, A second outlet for discharging the second toner contained in the second toner chamber to the outside of the second cartridge, It has a second pipe configured to communicate with the second discharge port, through which the second toner discharged from the second discharge port passes, The first toner in the first toner chamber is discharged from the first outlet and transported to the first toner storage section via the first tube by air taken in from the first intake port of the first cartridge. The air taken in from the second intake port of the second cartridge causes the second toner in the second toner chamber to be discharged from the second outlet port and transported to the second toner storage section via the second tube. The total length of the first tube is equal to the total length of the second tube. An image forming apparatus characterized by the following features.

12. The first tube and the second tube are tubes having the same inner diameter. The image forming apparatus according to feature 11.

13. The first developing container and the second developing container each extend in a longitudinal direction along the horizontal direction, and each has one end and the other end, The first tube is positioned such that, when viewed in the direction of gravity, it passes through one end of the first developing container in the longitudinal direction, The second tube is positioned such that, when viewed in the direction of gravity, it passes through the other end of the second developing container in the longitudinal direction. The image forming apparatus according to feature 11.

14. The first developing container and the second developing container each extend in a longitudinal direction along the horizontal direction, and each has one end and the other end, The first tube is positioned such that, when viewed in the direction of gravity, it passes through one end of the first developing container in the longitudinal direction, The second tube is positioned such that, when viewed in the direction of gravity, it passes through one end of the second developing container in the longitudinal direction. The image forming apparatus according to feature 11.

15. The main body of the device has a control unit that controls the pump section, The pump section comprises a first pump that discharges air for intake into the first intake of the first air chamber, and a second pump that discharges air for intake into the second intake of the second air chamber. The control unit is capable of independently controlling the drive of the first pump and the second pump. The image forming apparatus according to feature 11.

16. The first discharge port and the first pipe are provided in the first toner chamber. The end of the first pipe opposite to the end connected to the outlet is configured to open toward the first filter. The second discharge port and the second pipe are provided in the second toner chamber. The end of the second pipe opposite to the end connected to the outlet is configured to open toward the second filter. The image forming apparatus according to feature 11.

17. An image forming apparatus, A cartridge that holds toner, The device body, which allows the aforementioned cartridge to be attached and detached, The pump section that discharges air, A developing container including a toner storage section for storing the toner, the developing container being positioned above the cartridge, A tube having a first end communicating with the inside of the cartridge and a second end communicating with the inside of the toner storage section, extending from the first end to the second end and through which the toner passes, The device comprises a main body having, The aforementioned cartridge is A toner chamber for storing the aforementioned toner, A filter configured to obstruct the passage of the toner and allow the passage of air, An air chamber adjacent to the toner chamber via the aforementioned filter, the air chamber having an intake for taking in air discharged from the pump section, An outlet for discharging the toner contained in the toner chamber to the outside of the cartridge, It has a pipe configured to communicate with the aforementioned discharge port, through which the toner discharged from the discharge port passes, The toner in the toner chamber is discharged from the outlet and transported to the toner storage section via the tube by air taken in from the intake port of the cartridge. The tube includes, in the direction in which the toner is transported, a first portion and a second portion extending between the first and second ends at an inclination angle greater than 60 degrees with respect to the vertical or horizontal direction, and a third portion extending between the first and second portions in the horizontal, downward, or upward direction with respect to the horizontal at an inclination of 15 degrees or less. An image forming apparatus characterized by the following features.

18. The length of the first portion of the tube is shorter than the length of the third portion. The image forming apparatus according to feature 17.

19. The length of the second portion of the tube is shorter than the length of the third portion. The image forming apparatus according to feature 18.

20. The first and second parts extend vertically. The image forming apparatus according to feature 17.

21. The tube includes, in the direction in which the toner is transported, a fourth portion provided between the first end and the first portion and extending in the horizontal direction, a downward sloping direction, or an upward sloping direction of 15 degrees or less with respect to the horizontal direction, and a fifth portion provided between the second portion and the second end and extending in the horizontal direction, a downward sloping direction, or an upward sloping direction of 15 degrees or less with respect to the horizontal direction. The image forming apparatus according to feature 17.

22. The lengths of the first and second portions in the vertical direction are each half the length of the tube in the vertical direction. The image forming apparatus according to feature 17.

Images