Image forming apparatus

Abstract

An image forming apparatus includes a toner storage unit including a first toner containing portion, a developing unit including a developing member and a second toner containing portion, a toner transfer path configured to transfer toner from the toner storage unit to the developing unit, a first pump configured to eject air to feed toner in the first toner containing portion toward the toner transfer path, and a second pump configured to eject air to feed toner in the toner transfer path toward the second toner containing portion. The toner transfer path includes a first connection port connected to the first toner containing portion, a second connection port connected to the second toner containing portion, and a third connection port connected to the second pump. Toner is transferred from the first connection port to the second connection port with air ejected from the second pump.

Description

Technical Field

[0001] This disclosure relates to an electrophotographic image forming apparatus. Background Technology

[0002] In electrophotographic image forming apparatus, a well-known configuration is that a toner storage unit containing toner for image forming and a developing unit performing the electrophotographic process can be attached to and detached from the apparatus body.

[0003] Japanese Patent No. 4678735 discloses a configuration in which a pump that generates an airflow for transporting toner supplies toner from a toner storage unit to a developing unit. In this configuration, the toner in the toner storage unit is transported to a toner transport path by the airflow generated by the pump, and then to the developing unit via the toner transport path.

[0004] However, in the above configuration, toner may remain in the toner transport path that transfers toner from the toner storage unit to the developing unit. When residual toner remains in the toner transport path for an extended period, or when the toner is exposed to high temperatures, its fluidity may decrease. When toner with reduced fluidity remains in the toner transport path, the amount of toner to be supplied subsequently is reduced, and the required amount of toner is not supplied to the developing unit, which can lead to image defects. Summary of the Invention

[0005] Therefore, the purpose of this disclosure is to provide an image forming apparatus capable of suppressing image defects.

[0006] According to some embodiments, the image forming apparatus of this disclosure is characterized by comprising: a toner storage unit including a first toner receiving portion configured to contain toner therein; a photosensitive member; a developing unit including a developing member configured to develop an electrostatic latent image formed on the photosensitive member, and a second toner receiving portion configured to contain toner to be supplied to the developing member; a toner transport path configured to transport toner from the toner storage unit to the developing unit; and a first pump connected to the first toner receiving portion. The device comprises a portion and is configured to inject air to feed toner in the first toner receiving portion toward the toner transport path; and a second pump connected to the toner transport path and configured to inject air to feed toner in the toner transport path toward the second toner receiving portion, wherein the toner transport path includes a first connection port connected to the first toner receiving portion, a second connection port connected to the second toner receiving portion, and a third connection port connected to the second pump, and wherein the toner, together with the air injected from the second pump, is transported from the first connection port to the second connection port.

[0007] The features of this disclosure will become apparent from the following description of embodiments with reference to the accompanying drawings. The following description of the embodiments is by way of example. Attached Figure Description

[0008] Figure 1 This is a cross-sectional view showing a schematic configuration of an image forming apparatus.

[0009] Figure 2 This is a cross-sectional view of the developing unit.

[0010] Figure 3 This is a cross-sectional view of the toner storage unit.

[0011] Figure 4 This is a cross-sectional view of the toner storage unit.

[0012] Figure 5 This is an exploded 3D view of the first pump.

[0013] Figure 6A and Figure 6B The diagrams show the expansion and contraction operations of the first pump, respectively.

[0014] Figure 7A and Figure 7B This is a diagram showing the operation of the first pump.

[0015] Figures 8A to 8C This is a diagram showing the operation of the second pump.

[0016] Figure 9This is a cross-sectional view showing a schematic configuration of the toner delivery path and the second pump.

[0017] Figure 10 This is a cross-sectional view of the toner transport section.

[0018] Figure 11 This is a graph showing the static pressure of the first and second pumps.

[0019] Figure 12 This is a graph showing the ventilation resistance of the second pump and the ventilation resistance of the ventilation component.

[0020] Figure 13 This is a diagram illustrating the operation of the first and second pumps during the toner supply process.

[0021] Figure 14A and Figure 14B This is a diagram showing the pump in its first state.

[0022] Figure 15A and Figure 15B This is a diagram showing the second state of the pump.

[0023] Figure 16A and Figure 16B This is a diagram showing the third state of the pump.

[0024] Figure 17A and Figure 17B This is a diagram showing the fourth state of the pump.

[0025] Figure 18A and Figure 18B This is a diagram showing the pump in its fifth state.

[0026] Figure 19A and Figure 19B This is a diagram showing the sixth state of the pump. Detailed Implementation

[0027] In the following description, various exemplary embodiments (examples), features, and aspects of the present disclosure will be given with reference to the accompanying drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in the embodiments may be appropriately varied depending on the configuration of the device to which the present disclosure is applied, various conditions, etc. Therefore, the dimensions, materials, shapes, and relative arrangements of the components described in the embodiments are not intended to limit the scope of the present disclosure to the following embodiments. Furthermore, not all features described in the following embodiments are necessary for the technical solutions provided by the present disclosure.

[0028] First Embodiment

[0029] As a first embodiment, an example in which this disclosure is applied to an electrophotographic image forming apparatus will be described. The image forming apparatus IF according to the first embodiment is an electrophotographic laser beam printer that forms an image on a sheet S used as a recording medium using a developer (toner) based on image information transmitted from an external device (such as a personal computer). However, the scope of this disclosure is not limited to the image forming apparatus according to the following embodiments, and this disclosure is also applicable to image forming apparatuses such as copiers, printers, multifunction peripherals, and commercial printing equipment. Examples of recording media include sheet materials made of various materials and having various shapes, such as paper (including plain paper and cardboard), plastic film, coated paper, sheets with special shapes (such as envelopes or index paper), and fabrics.

[0030] Overall configuration of image forming equipment

[0031] The general configuration of the image forming apparatus IF according to the first embodiment of the present disclosure will be described. Figure 1 This is a cross-sectional view showing a schematic configuration of an image forming apparatus IF. The image forming apparatus IF includes an apparatus body A, a developing unit B installed in the apparatus body A, and a toner storage unit C.

[0032] In this specification, the device body A refers to the portion of the image forming apparatus IF excluding the developing unit B and the toner storage unit C, and includes the housing of the image forming apparatus IF and various units disposed within the housing. Besides the mounting portions for the developing unit B and the toner storage unit C, the device body A also includes a pickup roller 5a, a pair of transfer rollers 5b, a transfer roller 7, a fixing unit 9, a pair of discharge rollers 5c, and a discharge tray 10 arranged in the direction of conveying the sheet S from the sheet tray 4. Furthermore, the image forming apparatus IF includes a control unit 80, which controls the operation of the corresponding parts. The control unit 80 can be configured as, for example, a computer including a processor, memory, storage devices, I / O, etc.

[0033] The developing unit B includes a photosensitive drum 1 (photosensitive component), a charging roller 11 (charging component), a developing roller 2 (developing component), a developing blade 15, and a toner chamber 12. The toner storage unit C includes a toner receiving portion 16 and a first pump 35. The toner chamber 12 and the toner receiving portion 16 are connected to each other via a toner transport path 28. In this embodiment, the developing unit B and the toner storage unit C are configured to be attachable to and detachable from the device body A. However, this configuration is not limited to this; the developing unit B and the toner storage unit C can be fixed to the device body A.

[0034] The orientation of the image forming apparatus IF, mounted on a horizontal surface and in a usage posture, is defined as follows. In the vertical direction defined as the Y-axis, the upward direction is defined as the Y1 direction, and the downward direction is defined as the Y2 direction. Figure 1 The x-axis is defined horizontally to the left and right, with the leftward direction defined as the x1 direction and the rightward direction defined as the x2 direction. Figure 1 In the horizontal depth direction defined by the Z-axis, the forward direction is defined as the Z1 direction and the backward direction is defined as the Z2 direction. Figure 1 This is a cross-sectional view of the image forming device IF when viewed along the Z2 direction.

[0035] Image formation process

[0036] The image forming process (i.e., image forming operation) performed by the image forming apparatus IF will be described. When the image forming apparatus IF receives a signal to begin image forming on the sheet S, the photosensitive drum 1 is driven to rotate around a rotation axis parallel to the Z-axis. Figure 1 The roller rotates in the direction indicated by arrow R. The charging roller 11 contacts the outer peripheral surface of the photosensitive drum 1 to charge the surface of the photosensitive drum 1 uniformly and evenly. The laser scanner 3 installed in the main body of the device A irradiates the photosensitive drum 1 with a laser beam L based on image information and performs an exposure operation to write an electrostatic latent image on the surface of the photosensitive drum 1.

[0037] The toner T contained in the toner chamber 12 is fed toward the developing roller 2 via a developing agitator 13 rotatably disposed in the toner chamber 12 about a rotation axis parallel to the Z-axis. The toner T is then supplied to the developing roller 2 and is carried as a thin layer on the surface of the developing roller 2 by the developing doctor blade 15. The toner T reaching the developing area of ​​the developing roller 2 facing the photosensitive drum 1 is transferred from the developing roller 2 to the surface of the photosensitive drum 1 according to the potential distribution on the surface of the photosensitive drum 1. Therefore, the electrostatic latent image on the surface of the photosensitive drum 1 is visualized as a toner image.

[0038] In parallel with this process, the sheet S is fed at a timing synchronized with the exposure operation performed by the laser scanner 3. A pick-up roller 5a feeds the sheet S stacked on the sheet tray 4 from the sheet tray 4. A pair of transfer rollers 5b receive the sheet S from the pick-up roller 5a and transfer it to the transfer section between the photosensitive drum 1 and the transfer roller 7. Then, by applying a bias voltage to the transfer roller 7, the toner image carried on the photosensitive drum 1 is transferred onto the sheet S.

[0039] The sheet S, on which the toner image is transferred, is conveyed along the conveyor rail 8 to the fixing device 9. The fixing device 9 applies heat and pressure to the toner image on the sheet S through the heating roller 9a and the pressure roller 9b, thereby fixing the image onto the sheet S. The sheet S with the image fixed on it is discharged through a pair of discharge rollers 5c onto the discharge tray 10 located in the upper part of the main body A of the device.

[0040] Developing unit

[0041] refer to Figure 2 This will describe the overall configuration of developing unit B. Figure 2 This is a cross-sectional view showing a schematic configuration of the developing unit B when viewed along the Z2 direction.

[0042] In addition to the aforementioned photosensitive drum 1, charging roller 11, developing roller 2, developing blade 15, toner chamber 12, etc., the developing unit B of this embodiment includes a receiving port 24, which receives toner T supplied from the toner storage unit C. The receiving port 24 is located at the upper end of the toner chamber 12, opens along the Y1 direction, and is connected to the toner transport path 28 connecting the developing unit B and the toner storage unit C.

[0043] Toner storage unit

[0044] Next, refer to Figure 3 and Figure 4 This will describe the overall configuration of the toner storage unit C. Figure 3 This is a cross-sectional view showing a schematic configuration of the toner storage unit C when viewed along the Z2 direction. Figure 4 This is a cross-sectional view showing a schematic configuration of the toner storage unit C when viewed along the X2 direction.

[0045] like Figure 3 As shown, the toner storage unit C includes a toner receiving portion 16 and a first pump 35. The toner receiving portion 16 is a space surrounded by a frame body 31, in which toner T is contained, and is connected to the first pump 35. A stirring member 53, a screw 54, and a partition wall 55 are disposed within the toner receiving portion 16. The toner receiving portion 16 includes a communication path 48, a toner chamber 16a, a toner discharge chamber 16b, and a discharge port 27. The toner receiving portion 16 is divided into multiple spaces by the partition wall 55, including spaces such as the toner chamber 16a, the communication path 48, and the toner discharge chamber 16b.

[0046] In this embodiment, the first pump 35 is a bellows pump. A bellows pump has a bellows shape and expands and contracts to change its internal volume, thereby performing suction and discharge. It should be noted that the pump used as the first pump 35 is not limited to a bellows pump, and can also be other pumps, such as piston pumps or plunger pumps, as long as the pump can perform suction and discharge by changing its volume. Furthermore, the first pump 35 is arranged in the toner storage unit C, but it can also be arranged in the main body of the device A and connected to the toner receiving portion 16.

[0047] The stirring member 53 is drivably connected to a drive source (not shown) of the device body A and is supported by the frame body 31 in a rotatable manner about a rotation axis parallel to the X-axis. The stirring member 53 includes a rotating shaft 53a and a stirring sheet 53b, which is a flexible sheet and serves as a transfer member. The screw 54 is a transfer member, which is supported by the frame body 31 in a rotatable manner about a rotation axis parallel to the X-axis and transfers the toner T along this rotation axis to the communication path 48 and the toner discharge chamber 16b. That is, the rotation axis of the screw 54 is substantially parallel to the rotation axis of the stirring member 53.

[0048] The connecting path 48 is a space that allows communication between the toner chamber 16a and the toner discharge chamber 16b, and allows the toner T to move within this space. At least a portion of the screw 54 is arranged in the connecting path 48. The toner discharge chamber 16b is arranged downstream of the connecting path 48 in the direction in which the screw 54 transmits the toner T.

[0049] The toner discharge chamber 16b includes a discharge port 27. The discharge port 27 is an opening that allows communication between the interior and exterior of the frame body 31 and discharges the toner T to the exterior of the frame body 31 (i.e., in the direction indicated by arrow E2). In this embodiment, the direction indicated by arrow E2 corresponds to the Y2 direction.

[0050] Then, refer to Figure 3 and Figure 4 A method for transferring toner T within a toner storage unit C is described. For example... Figure 4 As shown, when the toner storage unit C receives a driving force from the device body A, the rotating shaft 53a is driven, and the stirring sheet 53b rotates in the direction indicated by arrow H, and the toner T is transferred to the screw 54. Next, as... Figure 3As shown, toner T is conveyed via screw 54 through connecting path 48 (i.e., in the direction indicated by dashed arrow E1) to toner discharge chamber 16b. The inner diameter of the partition wall 55 forming connecting path 48 corresponds to the outer diameter of screw 54. With this configuration, the toner T conveyed by screw 54 is scraped by the inner diameter of connecting path 48, thereby enabling a constant amount of toner T to be conveyed along the toner conveying direction to the downstream toner discharge chamber 16b.

[0051] As described above, the image forming apparatus IF according to this embodiment includes a toner receiving portion 16 (i.e., a first toner receiving portion) and a toner chamber 12 (i.e., a second toner receiving portion) as two toner receiving portions. Furthermore, the apparatus body A includes a toner transport path 28 as a transport path for transporting toner T from the toner receiving portion 16 to the toner chamber 12.

[0052] First pump

[0053] Next, refer to Figure 5 , Figure 6A and Figure 6B The configuration for driving the first pump 35 and the operation of the first pump 35 will be described. Figure 5 This is an exploded 3D view of the first pump, 35. Figure 6A This is a view showing the expansion operation of the first pump 35, and a cross-sectional view of the first pump 35 when viewed along the Z2 direction. Figure 6B This is a view showing the contraction operation of the first pump 35, and a cross-sectional view of the first pump 35 when viewed along the Z2 direction.

[0054] First, the configuration for driving the first pump 35 will be described. The first pump 35 includes a bellows member 33 having a bellows shape and configured to expand and contract, and a connecting gear 30 and a connecting rod member 32 serving as components for expanding and contracting the bellows member 33. The first pump 35 injects air to feed the toner in the toner receiving portion 16 toward the toner transport path 28.

[0055] The connecting rod gear 30 includes a connecting rod recess 30a and a gear portion 30b. When the gear portion 30b receives a driving force from a drive gear (not shown), the connecting rod gear 30 can rotate about a rotation axis parallel to the X-axis in the direction indicated by arrow J. The connecting rod member 32 includes an engagement portion 32a that engages with the bellows member 33 and an engagement portion 32b that engages with the connecting rod gear 30. The engagement portion 32a engages with the pump engagement portion 33b of the bellows member 33, and the engagement portion 32b engages with the connecting rod recess 30a of the connecting rod gear 30.

[0056] Next, the operation of the first pump 35 will be described. For example... Figure 6A and Figure 6BAs shown, the bellows member 33 includes a frame body engagement portion 33c that engages with the frame body 31. In this embodiment, the frame body engagement portion 33c is located at the end of the bellows member 33 along the X2 direction. When the frame body engagement portion 33c engages with the frame body 31 of the toner storage unit C, the bellows member 33 is fixed to the frame body 31. Therefore, the suction and discharge ports 33d of the first pump 35 located in the bellows member 33 communicate with the interior of the frame body 31. When the connecting rod gear 30 rotates, the engagement portion 32b slides along the connecting rod groove 30a, and the connecting rod member 32 reciprocates in the directions indicated by arrows G11 and G12. In conjunction with this movement, the bellows member 33, which engages with the connecting rod member 32, repeatedly expands in the direction indicated by arrow G11 and contracts in the direction indicated by arrow G12. In other words, when the first pump 35 (i.e., the bellows member 33) expands, it draws in air through the intake and exhaust ports 33d, thereby generating an airflow toward the interior of the first pump 35 in the direction indicated by arrow F11. Furthermore, when the first pump 35 (i.e., the bellows member 33) contracts, it exhausts air through the intake and exhaust ports 33d, thereby generating an airflow toward the exterior of the first pump 35 in the direction indicated by arrow F12. In this embodiment, the direction indicated by arrow G11 is substantially the same as the X1 direction, and the direction indicated by arrow G12 is substantially the same as the X2 direction.

[0057] In this embodiment, the bellows component 33 (i.e., the first pump 35) is in an expanded state (i.e., Figure 6A The volume V10 in the state shown is 20 ml, and in the contracted state (i.e., Figure 6B The volume V11 in the indicated state is 3 ml. In the following description, the volume of the bellows member 33 is considered to be the volume of the first pump 35. Furthermore, the first pump 35 expands and contracts 2.5 times per second.

[0058] Second pump

[0059] Next, refer to Figures 8A to 8C The configuration and operation of the second pump 36 will be described. Figure 8A This is a schematic diagram of the second pump 36 in standby mode (i.e., pump stopped). Figure 8B This is a schematic diagram of the second pump 36 during the suction process. Figure 8C This is a schematic diagram of the second pump 36 during the discharge process.

[0060] First, the configuration of the second pump 36 will be described. For example... Figure 8AAs shown, the second pump 36 in this embodiment is a diaphragm pump. The second pump 36 includes a volume change section 36a, an intake port 36e, an exhaust port 36d, a first valve 36b, a second valve 36c, a diaphragm 36f, a first stop section 36g, and a second stop section 36h. The second pump 36 injects air to feed the toner in the toner delivery path 28 to the toner chamber 12, which serves as the second toner receiving section.

[0061] The intake port 36e is an opening for drawing air from outside the second pump 36 into the second pump 36, and allows communication between the volume change portion 36a and the outside of the second pump 36. The discharge port 36d is an opening for discharging air drawn from outside the second pump 36, and allows communication between the volume change portion 36a and the toner delivery path 28. The intake port 36e is located at the end of the second pump 36 along the X2 direction and communicates with the outside of the second pump 36. The discharge port 36d is located at the end of the second pump 36 along the X1 direction and communicates with the toner delivery path 28 via a path 36j extending from the discharge port 36d along the X1 direction.

[0062] The first valve 36b is supported in a manner that allows it to swing about a fulcrum 36m in the direction indicated by arrow K1, and is configured to open and close the intake port 36e. Similarly, the second valve 36c is supported in a manner that allows it to swing about a fulcrum 36k in the direction indicated by arrow K2, and is configured to open and close the discharge port 36d. A first stop portion 36g is configured to restrict the swing of the first valve 36b, and a second stop portion 36h is configured to restrict the swing of the second valve 36c. The first stop portion 36g is located on the outer side of the first valve 36b relative to the volume change portion 36a (i.e., on the X2 direction side in this embodiment). Furthermore, the second stop portion 36h is located on the inner side of the second valve 36c relative to the volume change portion 36a (i.e., on the X2 direction side in this embodiment). Therefore, both the first valve 36b and the second valve 36c can swing in the X1 direction, but their swing in the X2 direction is restricted.

[0063] In the following text, such as Figure 8C As shown, the state in which the first valve 36b abuts against the first stop portion 36g and is closed to seal the suction port 36e is defined as the "closed state". Furthermore, as... Figure 8B As shown, the state in which the first valve 36b swings from the closed state along the X1 direction and is opened to open the suction port 36e is defined as the "open state". Similarly, as Figure 8B As shown, the state in which the second valve 36c abuts against the second stop portion 36h and is closed to seal the discharge port 36d is defined as the "closed state". Furthermore, as... Figure 8CAs shown, the state in which the second valve 36c swings from the closed state along the X1 direction and is opened to open the discharge port 36d is defined as the "open state".

[0064] like Figure 8B and Figure 8C As shown, the volume change portion 36a (i.e., the portion surrounded by the dashed line) is configured such that the diaphragm 36f is in the direction indicated by arrow G21 (see [reference]). Figure 8B ) and the direction indicated by arrow G22 (see Figure 8C The reciprocating motion allows for volume changes. In this embodiment, the direction indicated by arrow G21 is substantially the same as the Y2 direction, and the direction indicated by arrow G22 is substantially the same as the Y1 direction.

[0065] Next, the suction operation of the second pump 36 will be described. For example... Figure 8B As shown, when the diaphragm 36f shifts along the expansion direction (i.e., the direction indicated by arrow G21), the pressure within the volume change section 36a decreases. This pressure reduction in the volume change section 36a generates an airflow towards the volume change section 36a in the directions indicated by arrows F21 and F23, thereby pushing the first valve 36b in the X1 direction and the second valve 36c in the X2 direction. When pressurized by air, the first valve 36b opens, and the second valve 36c abuts against the second stop portion 36h and is closed. Therefore, air flows from the intake port 36e in the direction indicated by arrow F21 to the volume change section 36a, and air outside the second pump 36 is drawn into the volume change section 36a. On the other hand, the second valve 36c prevents air from flowing into the volume change section 36a through the discharge port 36d. In this embodiment, the direction indicated by arrow F21 is substantially the same as the X1 direction, and the direction indicated by arrow F23 is substantially the same as the X2 direction.

[0066] Next, the discharge operation of the second pump 36 will be described. For example... Figure 8C As shown, when the diaphragm 36f shifts in the contraction direction (i.e., the direction indicated by arrow G22), the pressure within the volume change section 36a increases. This pressure increase in the volume change section 36a generates an airflow from the volume change section 36a in the directions indicated by arrows F22 and F24, thereby pushing the first valve 36b in the X2 direction and the second valve 36c in the X1 direction. When pressurized by air, the first valve 36b abuts against the first stop portion 36g and is closed, while the second valve 36c is opened. Therefore, the air within the volume change section 36a is discharged towards the discharge port 36d in the direction indicated by arrow F22. On the other hand, the first valve 36b prevents air from flowing out of the volume change section 36a through the intake port 36e. In this embodiment, the direction indicated by arrow F22 is substantially the same as the X1 direction, and the direction indicated by arrow F24 is substantially the same as the X2 direction.

[0067] In other words, the first valve 36b is configured to switch between an open state and a closed state. In the open state, it allows air to flow into the volume change section 36a through the intake port 36e (in the direction indicated by arrow F21), and in the closed state, it prevents air from flowing out of the volume change section 36a through the intake port 36e (in the direction indicated by arrow F24). Furthermore, the second valve 36c is configured to switch between an open state and a closed state. In the open state, it allows air to flow out of the volume change section 36a through the exhaust port 36d (in the direction indicated by arrow F22), and in the closed state, it prevents air from flowing into the volume change section 36a through the exhaust port 36d (in the direction indicated by arrow F23).

[0068] In this embodiment, the second pump 36 (i.e., the volume change portion 36a) is in an expanded state (i.e., Figure 8B The volume V20 in the state shown is 2.3 ml, and in the contracted state (i.e., Figure 8C The volume V21 in the indicated state is 2.0 ml. In the following description, the volume of the volume change portion 36a is considered to be the volume of the second pump 36. Furthermore, the second pump 36 expands and contracts 20 times per second.

[0069] It should be noted that in this embodiment, the second pump 36 is disposed in the device body A, and the discharge port 36d is connected to the toner transport path 28. However, this configuration is not limited to this. For example, the second pump 36 may be disposed in the toner storage unit C.

[0070] The states of the diaphragm 36f, the first valve 36b, and the second valve 36c when the second pump 36 operates independently have been described above. The situation where the first pump 35 and the second pump 36 operate in coordination with each other will be described in detail later.

[0071] Toner transport path

[0072] Next, refer to Figure 1 and Figure 9 This section will describe a schematic configuration of the toner transport path 28 used for transporting toner T. Figure 9 This is a cross-sectional view showing a schematic configuration of the toner delivery path 28 and the second pump 36 when viewed along the Z2 direction.

[0073] The toner transport path 28 is a space formed by a cylindrical hollow component disposed within the main body A of the device. One end of the toner transport path 28 forms a first connection port 28a and is connected to a discharge port 27 disposed in the toner receiving portion 16. The first connection port 28a is located directly below the toner receiving portion 16 of the toner storage unit C and opens along the Y1 direction. The other end of the toner transport path 28 forms a second connection port 28b and is connected to a receiving port 24 of the toner chamber 12 of the developing unit B. The second connection port 28b is located directly above the toner chamber 12 and opens along the Y2 direction.

[0074] exist Figure 9 In the toner transport path 28, the midpoint 28c between the first connection port 28a and the second connection port 28b is indicated by a dashed line. In other words, the midpoint 28c of the toner transport path 28 refers to the point located midway along the extension direction of the toner transport path 28, between the discharge port 27 of the toner container portion 16 and the receiving port 24 of the developing unit B.

[0075] With reference to the midpoint 28c of the toner transport path 28, the second pump 36 is arranged on the side of the first connection port 28a (i.e., the toner storage unit C side). A path 36j extending from the discharge port 36d of the second pump 36 connects to the toner transport path 28 and forms a branch portion 28d in the toner transport path 28. That is, the toner transport path 28 includes a connecting port 28e as a third connection port, which communicates with the path 36j of the second pump 36. The branch portion 28d is configured to include a portion connected to the first connection port 28a, a portion connected to the second connection port 28b, and a portion connected to the connecting port 28e, which serves as the third connection port. In other words, the toner transport path 28 includes a first connection port 28a connected to the toner receiving portion 16 (serving as the first toner receiving portion), a second connection port 28b connected to the toner chamber 12 (serving as the second toner receiving portion), and a connecting port 28e connected to the second pump 36 (serving as the third connection port).

[0076] In this embodiment, the discharge port 27 of the toner storage unit C is arranged on the Y2 direction side and the X2 direction side relative to the receiving port 24 of the developing unit B. That is, the first connection port 28a constituting one end of the toner transport path 28 is located on the Y2 direction side (lower side) and the X2 direction side relative to the second connection port 28b constituting the other end. The toner transport path 28 includes a region M1 extending in the Y2 direction (vertically downward direction) from the discharge port 27 of the toner storage unit C, which opens in the Y2 direction. That is, region M1 is the region including the first connection port 28a. In addition, the toner transport path 28 includes a region M2 extending in the horizontal X1 direction from the lower end of region M1, and a region M3 extending in the Y1 direction (vertically upward direction) from the end of region M2 in the X1 direction. In addition, the toner transport path 28 includes a region M4 extending in the horizontal X1 direction from the upper end of region M3, and a region M5 extending in the Y2 direction (vertically downward direction) from the end of region M4 in the X1 direction. The second connection port 28b is located at the lower end of region M5, and region M5 is connected to the receiving port 24 of the developing unit B, which is open along the Y1 direction.

[0077] The toner transport path 28 also includes a vent 28f, which is provided with a vent member 26 that allows communication between the inside and outside of the toner transport path 28. The vent member 26 is configured to allow air to pass through while preventing the passage of toner T. The vent 28f is arranged vertically above the receiving port 24 of the developing unit B and opens in the Y1 direction to allow communication between the inside and outside of the toner transport path 28. The vent member 26 is configured to cover the vent 28f. That is, the vent 28f and the vent member 26 are arranged closer to the second connection port 28b side (i.e., the developing unit B side) relative to the midpoint 28c. In other words, the vent 28f communicating with the outside is provided in the portion of the toner transport path 28 between the midpoint 28c and the toner chamber 12, which serves as the second toner receiving portion. With this arrangement and configuration, when air is fed into the developing unit B along with the toner T, the internal pressure inside the developing unit B increases, thereby preventing the toner T from leaking to the outside. However, this configuration is not limited to this. For example, the vent 28f can be provided in the toner chamber 12.

[0078] As described above, the toner transport path 28 has two openings, namely a communication port 28e and a vent 28f, between a first connection port 28a at one end of the toner transport path 28 and a second connection port 28b at the other end. In this embodiment, the communication port 28e opens along the X2 direction and communicates with the second pump 36, and is formed at the end of the portion extending from region M2 toward the Y2 direction along the X2 direction.

[0079] In this embodiment, the vent 28f and the venting member 26 are arranged vertically above the receiving port 24 of the developing unit B (i.e., on the Y1 direction side). More specifically, the vent 28f and the venting member 26 are arranged directly above the receiving port 24 and, when viewed along the Y-axis (i.e., the vertical direction), are arranged at a position overlapping with the receiving port 24. It should be noted that the venting member 26 can be any type that allows air to pass through while blocking the toner T, and can be appropriately selected depending on the toner T used.

[0080] As the hollow component forming the toner transport path 28, a flexible tube made of materials such as rubber or silicone, a resin tube, or a metal tube can be used. Furthermore, in the configuration using airflow to transport the toner T, the shape of the toner transport path 28 is not limited to the shape formed by combining portions extending in the horizontal and vertical directions in this embodiment, but can be freely configured to include portions extending in an inclined direction or arc-shaped portions.

[0081] In the following text, before describing the supply of toner T from toner storage unit C to developing unit B, the relationship between the first pump 35 and the second pump 36, and the relationship between the ventilation resistance of venting member 26 and the ventilation resistance of the second pump 36, will be described. Next, the toner supply operation will be described as three separate operations, namely the first toner supply operation to the third toner supply operation.

[0082] The relationship between the first pump and the second pump

[0083] refer to Figure 7A , Figure 7B , Figures 8A to 8C , Figure 10 and Figure 11 This will describe the relationship between the first pump 35 and the second pump 36. Figure 7A It is a diagram showing the expansion operation of the first pump 35, and a cross-sectional view of the toner storage unit C when viewed along the Z2 direction. Figure 7B It is a diagram showing the contraction operation of the first pump 35, and a cross-sectional view of the toner storage unit C when viewed along the Z2 direction.

[0084] Figure 10 This is a cross-sectional view of the toner transport section when viewed along the Z2 direction, including the toner storage unit C, the developing unit B, and the toner transport path 28. In the following description, the static pressure of the first pump 35 is defined as P1, the static pressure of the second pump 36 is defined as P2, the static pressure at the branch portion 28d of the toner transport path 28 is defined as P3, the static pressure of the toner storage unit C is defined as P4, and the static pressure near the venting member 26 within the toner transport path 28 is defined as P5. Furthermore, static pressure P5 can also be referred to as the static pressure near the venting member 26.

[0085] Figure 11 The bar chart shows the static pressure of the first pump 35 and the second pump 36. In the chart, the horizontal axis represents the volume change of the first pump 35 and the second pump 36, and the vertical axis represents the pressure. With atmospheric pressure P0 as the reference value on the vertical axis, the bars of the bar chart extend upward when the static pressure is higher than atmospheric pressure P0, and extend downward when the static pressure is lower than atmospheric pressure P0. That is, Figure 11 The chart indicates whether the static pressure of each pump is higher or lower than atmospheric pressure P0. Figure 11 The charts indicate the static pressure P1a during the expansion process of the first pump 35, the static pressure P1b during the contraction process of the first pump 35, the static pressure P2a during the expansion process of the second pump 36, and the static pressure P2b during the contraction process of the second pump 36.

[0086] Reference Figure 11 Detailed description Figure 10 The relationship between the static pressure P1 of the first pump 35 and the static pressure P2 of the second pump 36 is shown. Figure 11 As shown, the static pressure P1a during the expansion process of the first pump 35 and the static pressure P2a during the expansion process of the second pump 36 are both lower than atmospheric pressure P0, and the static pressure P1b during the contraction process of the first pump 35 and the static pressure P2b during the contraction process of the second pump 36 are both higher than atmospheric pressure P0. The absolute value of the static pressure P1a during the expansion process of the first pump 35 (i.e., the difference from atmospheric pressure P0) is less than the absolute value of the static pressure P2a during the expansion process of the second pump 36. Similarly, the absolute value of the static pressure P1b during the contraction process of the first pump 35 (i.e., the difference from atmospheric pressure P0) is less than the absolute value of the static pressure P2b during the contraction process of the second pump 36. In this example, the pump's pressure performance is proportional to the sum of the absolute value of the static pressure during the contraction process (higher static pressure) and the absolute value of the static pressure during the expansion process (lower static pressure), that is, proportional to the difference between the static pressure during the contraction process and the static pressure during the expansion process. In other words, in this embodiment, the corresponding pump is configured such that the pressure performance of the first pump 35 is lower than that of the second pump 36.

[0087] The pressure performance of the first pump 35 and the second pump 36 will be described in more detail. First, the volume and internal pressure of the first pump 35 during operation will be described. For example... Figure 7A As shown, the first pump 35 undergoes a volume change along the pump expansion direction (i.e., the direction indicated by arrow G11). In this state, assuming the volume during the expansion process of the first pump 35 is defined as V10 and the volume of the toner containing portion 16 is defined as V30, the volume of the toner storage unit C is V10 + V30. Similarly, as... Figure 7BAs shown, the first pump 35 undergoes a volume change along the pump contraction direction (i.e., the direction indicated by arrow G12). In this state, assuming that the volume during the contraction process of the first pump 35 is defined as V11 and the volume of the toner containing portion 16 is defined as V30, the volume of the toner storage unit C is V11 + V30.

[0088] Here, it is assumed that the toner storage unit C is a closed system, and the volume of the first pump 35 decreases from V10 to V11 under an initial internal pressure of atmospheric pressure P0. According to Boyle's Law, the static pressure P1b during the contraction process of the first pump 35, after the volume change, is (V10+V30) / (V11+V30)×P0. As mentioned above, the volume V10 is 20 ml, and the volume V11 is 3 ml. Assuming that the volume V30 of the toner containing portion 16 is 1000 ml, the static pressure P1b during the contraction process of the first pump 35 is approximately 1.017 × P0. Since the toner storage unit C is not actually sealed, the static pressure P1b during the contraction process of the first pump 35 is less than this value.

[0089] Next, the volume and internal pressure of the second pump 36 during operation will be described. For example... Figure 8B As shown, the second pump 36 undergoes a volume change along the expansion direction of the diaphragm 36f (i.e., the direction indicated by arrow G21). In this state, it is assumed that the volume during the expansion process of the second pump 36 is defined as V20. Furthermore, as... Figure 8C As shown, the second pump 36 undergoes a volume change along the contraction direction of the diaphragm 36f (i.e., the direction indicated by arrow G22). In this state, it is assumed that the volume during the contraction process of the second pump 36 is defined as V21.

[0090] Here, it is assumed that the second pump 36 is a closed system, and that the volume of the second pump 36 decreases from V20 to V21 under the initial internal pressure of atmospheric pressure P0. According to Boyle's law, the static pressure P2b during the contraction process of the second pump 36 is (V20 / V21) × P0 after the volume change. As mentioned above, the volume V20 is 2.3 ml, and the volume V21 is 2.0 ml. Therefore, the static pressure P2b during the contraction process of the second pump 36 is 1.15 × P0.

[0091] Therefore, in this embodiment, since the first pump 35 is connected to the larger toner container 16, the difference between the static pressure P1b and atmospheric pressure P0 during the contraction process of the first pump 35 is smaller than the difference between the static pressure P2b and atmospheric pressure P0 during the contraction process of the second pump 36. In other words, the static pressure P2b during the contraction process of the second pump 36 is greater than the static pressure P1b during the contraction process of the first pump 35. Furthermore, based on the same calculation, the difference between the static pressure P1a and atmospheric pressure P0 during the expansion process of the first pump 35 is smaller than the difference between the static pressure P2a and atmospheric pressure P0 during the expansion process of the second pump 36. In other words, the static pressure P2a during the expansion process of the second pump 36 is less than the static pressure P1a during the expansion process of the first pump 35.

[0092] The relationship between the ventilation resistance of the ventilation component and the ventilation resistance of the second pump

[0093] refer to Figure 12 The relationship between the ventilation resistance of the ventilation component 26 and the ventilation resistance of the second pump 36 will be described. Figure 12 This is a bar chart showing the ventilation resistance of the venting member 26 and the ventilation resistance of the second pump 36 when the first valve 36b and the second valve 36c are open. Figure 12 In the diagram, the horizontal axis represents the target component, and the vertical axis represents the magnitude of the air resistance of the target component.

[0094] In the venting member 26 according to this embodiment, a plurality of fine pores are formed to prevent the toner T from passing through. Therefore, as Figure 12 As shown, when the first valve 36b and the second valve 36c of the second pump 36 are open, the ventilation resistance of the venting component 26 is greater than that of the second pump 36. The ventilation resistance of the venting component 26 can be adjusted according to the material, area, etc.

[0095] Toner supply operation

[0096] The operation of supplying toner T from toner storage unit C to developing unit B will be described. In the toner supply operation, toner T in the toner receiving portion 16 of toner storage unit C is transported to developing unit B by airflow via toner transport path 28. The toner supply operation is performed under the control of control unit 80, which controls the operation of first pump 35, second pump 36, toner storage unit C, etc.

[0097] In the toner supply operation according to this embodiment, the operation of the first pump 35 and the second pump 36 is performed as follows.

[0098] First toner supply operation: In this operation, the first pump 35 stops, while the second pump 36 operates simultaneously.

[0099] Second toner supply operation: In this operation, both the first pump 35 and the second pump 36 are in operation.

[0100] Third toner supply operation: In this operation, the first pump 35 stops, while the second pump 36 operates (same as the first toner supply operation).

[0101] In the toner supply operation, the control unit 80 controls the operation of each part, thereby executing the first toner supply operation, the second toner supply operation, and the third toner supply operation in that order. The first to third toner supply operations will be described sequentially below.

[0102] Figure 13 This diagram illustrates the operation of the first pump 35 and the second pump 36 during toner supply operation, and is also a conceptual diagram showing the switching timing of the operation of the first pump 35 and the second pump 36. In the toner transport section, which includes the developing unit B, the toner storage unit C, and the toner transport path 28, the magnitude relationship between the static pressures of the corresponding portions of the toner transport section varies according to the operating states of the first pump 35 and the second pump 36, thereby generating a predetermined airflow. Figure 13 The predetermined timings TL0 to TL5 are shown, under which changes such as airflow are observed.

[0103] A. First toner supply operation

[0104] First, refer to Figure 8A , Figure 10 , Figure 13 , Figure 14A , Figure 14B , Figure 15A and Figure 15B The following describes the first toner supply operation. In the description of the toner supply operation, the states of the toner delivery section are defined as follows: When the first pump 35 stops and the second pump 36 is in expansion operation, the state of the toner delivery section is defined as the first pump state. When the first pump 35 stops and the second pump 36 is in contraction operation, the state of the toner delivery section is defined as the second pump state.

[0105] Figure 14A and Figure 14B This is a diagram showing the pump in its first state. Figure 14A This is a cross-sectional view of the toner transport section in the first state of the pump when viewed along the Z2 direction. Figure 14B It is a bar chart showing the relationship between the static pressures P1 to P5 in the toner delivery section during the first state of the pump. Figure 15A and Figure 15B This is a diagram showing the second state of the pump. Figure 15A This is a cross-sectional view of the toner transport section in the second state of the pump when viewed along the Z2 direction. Figure 15B It is a bar chart showing the relationship between the static pressures P1 to P5 in the toner delivery section during the second state of the pump.

[0106] At timer TL0, the first pump 35 and the second pump 36 stop. At this time, the second pump 36 is in operation. Figure 8A The state shown.

[0107] When the second pump 36 starts operating, the first toner supply operation begins. Timing TL1 is the timing for the start of the second pump 36's operation, i.e., the timing for the start of the first toner supply operation. During the first toner supply operation, the second pump 36 alternately performs expansion and contraction operations. That is, during the first toner supply operation, the pump's state is... Figure 14A The pump's first state shown is the same as Figure 15A The pump alternates between the second states shown.

[0108] During the first toner supply operation, the screw 54 and the first pump 35 in the toner storage unit C stop, and the toner T is not discharged from the toner storage unit C.

[0109] like Figure 14B As shown, in the first state of the pump, due to the expansion operation of the second pump 36, the static pressure P2 of the second pump 36 becomes lower than the atmospheric pressure P0. Therefore, as Figure 14A As shown, the first valve 36b is pushed in the X1 direction to open, while the second valve 36c is pushed in the X2 direction to close. Then, an airflow is generated in the direction indicated by arrow F21 toward the side with static pressure P2 (which is lower than atmospheric pressure P0), and air flows into the second pump 36 from the outside through the suction port 36e.

[0110] On the other hand, in the first state of the pump, the static pressure P1 of the first pump 35, the static pressure P3 at the branch portion 28d of the toner transport path 28, the static pressure P4 of the toner storage unit C, and the static pressure P5 near the venting member 26 are essentially equal to atmospheric pressure P0. Therefore, there is essentially no airflow generated within the toner transport path 28.

[0111] like Figure 15B As shown, in the second state of the pump, due to the contraction operation of the second pump 36, the static pressure P2 of the second pump 36 becomes higher than the atmospheric pressure P0. Therefore, as Figure 15A As shown, the first valve 36b is pushed in the X2 direction to close, while the second valve 36c is pushed in the X1 direction to open. Then, an airflow is generated from the discharge port 36d of the second pump 36 in the direction indicated by arrow F22 toward the toner delivery path 28, and air flows from the second pump 36 into the toner delivery path 28.

[0112] Here, except for the discharge port 27, the toner storage unit C is sealed, and the first pump 35, the toner storage unit C, and the branch portion 28d are in communication with each other. Therefore, in the second pump state, the static pressure P4 of the toner storage unit C and the static pressure P1 of the first pump 35 become substantially equal to the static pressure P3 at the branch portion 28d of the toner transport path 28. On the other hand, since the venting member 26 is permeable, the static pressure P5 near the venting member 26 is lower than the static pressure P3 at the branch portion 28d of the toner transport path 28, and closer to atmospheric pressure P0. Therefore, an airflow is generated within the toner transport path 28 from the branch portion 28d toward the venting member 26 in the direction indicated by arrow F31, and the air is discharged to the outside of the toner transport path 28 through the venting member 26 in the direction indicated by arrow F32. It should be noted that the direction indicated by arrow F31 is along the extension direction of the toner transport path 28, and the direction indicated by arrow F32 is substantially the same as the Y1 direction.

[0113] As described above, during the first toner supply operation (from timing TL1 to timing TL2, which will be described later), the toner T in the toner storage unit C is not transferred to the developing unit B. Furthermore, air in the second pump 36 flows toward the venting member 26 through the toner transport path 28 and is discharged to the outside through the venting member 26.

[0114] As described above, in the toner supply operation, the second pump 36 starts operating before the first pump 35 in the first toner supply operation. This operational control can suppress blockage of the toner T in the toner delivery path 28 and prevent the toner T from seeping into the second pump 36.

[0115] B. Second toner supply operation

[0116] Next, we will refer to Figure 10 , Figure 11 , Figure 13 , Figure 16A , Figure 16B , Figure 17A , Figure 17B , Figure 18A , Figure 18B , Figure 19A and Figure 19BThe second toner supply operation is described. In this description, the states of the toner delivery section are defined as follows: When both the first pump 35 and the second pump 36 are in expansion operation, the state of the toner delivery section is defined as the third pump state. When both the first pump 35 and the second pump 36 are in contraction operation, the state of the toner delivery section is defined as the fourth pump state. When both the first pump 35 and the second pump 36 are in expansion operation, the state of the toner delivery section is defined as the fifth pump state. When both the first pump 35 and the second pump 36 are in contraction operation, the state of the toner delivery section is defined as the sixth pump state.

[0117] Figure 16A and Figure 16B This is a diagram showing the third state of the pump. Figure 16A This is a cross-sectional view of the toner transport section in the third state of the pump when viewed along the Z2 direction. Figure 16B It is a bar chart showing the relationship between the static pressures P1 to P5 in the toner delivery section during the third state of the pump. Figure 17A and Figure 17B This is a diagram showing the fourth state of the pump. Figure 17A This is a cross-sectional view of the toner transport section in the fourth state of the pump when viewed along the Z2 direction. Figure 17B It is a bar chart showing the relationship between the static pressures P1 to P5 in the toner delivery section during the fourth state of the pump. Figure 18A and Figure 18B This is a diagram showing the pump in its fifth state. Figure 18A This is a cross-sectional view of the toner transport section in the fifth state of the pump when viewed along the Z2 direction. Figure 18B It is a bar chart showing the relationship between the static pressures P1 to P5 in the toner delivery section during the fifth state of the pump. Figure 19A and Figure 19B This is a diagram showing the sixth state of the pump. Figure 19A This is a cross-sectional view of the toner transport section in the sixth state of the pump when viewed along the Z2 direction. Figure 19B It is a bar chart showing the relationship between the static pressures P1 to P5 in the toner delivery section during the sixth state of the pump.

[0118] When the first pump 35 starts operating, the second toner supply operation begins. Timing TL2 is the timing for the start of the first pump 35's operation, i.e., the timing for the end of the first toner supply operation and the start of the second toner supply operation. During the second toner supply operation, each of the first pump 35 and the second pump 36 alternately performs expansion and contraction operations. That is, during the second toner supply operation, the toner delivery section is in... Figure 16A The third state of the pump shown Figure 17A The fourth state of the pump shown Figure 18AThe fifth state of the pump shown, and Figure 19A Any of the sixth states of the pump shown.

[0119] like Figure 16B As shown, in the third state of the pump, due to the expansion operation of the second pump 36, the static pressure P2 of the second pump 36 becomes lower than the atmospheric pressure P0. Therefore, as Figure 16A As shown, the first valve 36b is pushed in the X1 direction to open. Then, an airflow is generated in the direction indicated by arrow F21 toward the side with static pressure P2 (which is lower than atmospheric pressure P0), and air flows into the second pump 36 from the outside through the suction port 36e.

[0120] In addition, such as Figure 16B As shown, in the third state of the pump, due to the expansion operation of the first pump 35, the static pressure P1 of the first pump 35 becomes lower than the atmospheric pressure P0. Therefore, as Figure 16A As shown, the second valve 36c is pushed in the X1 direction to open. Then, an airflow is generated in the direction indicated by arrow F11 toward the side with static pressure P1 (which is lower than atmospheric pressure P0), and air flows from the outside of the second pump 36 into the first pump 35 through the second pump 36 and the branch portion 28d.

[0121] As described above, in the third state of the pump, an airflow is generated in the opposite direction to the direction in which the toner T is discharged from the toner storage unit C to the toner transport path 28. Therefore, in the third state of the pump, the toner T is not discharged from the toner storage unit C.

[0122] In the fourth state of the pump, such as Figure 17B As shown, due to the expansion operation of the first pump 35, the static pressure P1 of the first pump 35 becomes lower than the atmospheric pressure P0. Furthermore, due to the contraction operation of the second pump 36, the static pressure P2 of the second pump 36 increases. Therefore, as... Figure 17A As shown, the second valve 36c is pushed open in the X1 direction. Then, an airflow is generated in the direction indicated by arrow F22, which is discharged from the second pump 36 and flows to the first pump 35.

[0123] In the fourth state of the pump, such as Figure 17B As shown, although the second pump 36 is in contraction operation, the second valve 36c is open and the second pump 36 is connected to the toner delivery path 28. Therefore, the static pressure P2 becomes lower than atmospheric pressure P0. Therefore, as... Figure 17A As shown, the first valve 36b opens, generating airflow from the outside to the first pump 35 in the direction indicated by arrow F11, thereby allowing air to flow from the outside of the second pump 36 into the first pump 35 through the second pump 36 and the branch portion 28d.

[0124] In other words, in the fourth state of the pump, airflow is generated in the opposite direction to the direction in which toner T is discharged from toner storage unit C to toner transport path 28, as in the third state of the pump. Therefore, in the fourth state of the pump, toner T is not discharged from toner storage unit C.

[0125] like Figure 18B As shown, in the fifth state of the pump, due to the contraction operation of the first pump 35, the static pressure P1 of the first pump 35 becomes higher than the atmospheric pressure P0, while simultaneously, due to the expansion operation of the second pump 36, the static pressure P2 of the second pump 36 becomes lower than the atmospheric pressure P0. Therefore, as Figure 18A As shown, the first valve 36b is pushed in the X1 direction to open, while the second valve 36c is pushed in the X2 direction to close. Then, an airflow is generated in the direction indicated by arrow F21 toward the side with static pressure P2 (which is lower than atmospheric pressure P0), and air flows into the second pump 36 from the outside through the suction port 36e.

[0126] In the fifth state of the pump, because the static pressure P1 of the first pump 35 becomes relatively higher than the static pressure at other locations, an airflow is generated from the first pump 35 toward the branch 28d of the toner transport path 28 in the direction indicated by arrow F12. This airflow causes the toner T in the toner storage unit C to be discharged along with the air into the branch 28d of the toner transport path 28. Figure 18A As shown, due to the closure of the second valve 36c, the static pressure P5 within the toner transport path 28 near the vent member 26 becomes relatively low. Therefore, the mixture of air and toner T in the toner transport path 28 flows towards the vent member 26 in the direction indicated by arrow F31. Then, only air flows from the vent member 26 and exits to the outside of the toner transport path 28 in the direction indicated by arrow F32, while toner T is not allowed to pass through the vent member 26. Thus, toner T and air separate from each other. The separated toner T falls into the receiving port 24 of the developing unit B due to gravity and is supplied to the developing unit B.

[0127] As described above, in the fifth state of the pump, the toner T is fed into the toner transport path 28 and transported to the developing unit B by the airflow generated by the contraction operation of the first pump 35.

[0128] like Figure 19B As shown, in the sixth state of the pump, due to the contraction operation of the first pump 35, the static pressure P1 of the first pump 35 becomes higher than the atmospheric pressure P0. Simultaneously, due to the contraction operation of the second pump 36, the static pressure P2 of the second pump 36 becomes higher than the atmospheric pressure P0. Therefore, as... Figure 19AAs shown, the first valve 36b is pushed in the X2 direction to close. On the other hand, the direction in which the second valve 36c is pushed is determined based on the relationship between the static pressure P1 of the first pump 35 and the static pressure P2 of the second pump 36. In this embodiment, as... Figure 11 As shown, the static pressure P2b during the contraction process of the second pump 36 is greater than the static pressure P1b during the contraction process of the first pump 35. Therefore, the second valve 36c is pushed in the X1 direction to open.

[0129] In the sixth state of the pump, the static pressure at the corresponding locations decreases in the following order: static pressure P2 of the second pump 36; static pressure P1 of the first pump 35; static pressure P4 of the toner storage unit C; static pressure P3 at the branch portion 28d; and static pressure P5 near the venting member 26 within the toner transport path 28. Therefore, an airflow (in the direction indicated by arrow F12) is generated from the first pump 35 toward the branch portion 28d of the toner transport path 28, thereby discharging the toner T from the toner storage unit C to the branch portion 28d and mixing it with the air within the branch portion 28d. Furthermore, an airflow is generated from the discharge port 36d of the second pump 36 toward the branch portion 28d of the toner transport path 28 in the direction indicated by arrow F22.

[0130] like Figure 19A As shown, at the branch 28d of the toner transport path 28, a mixture of air and toner T flowing in the direction indicated by arrow F12 mixes with air flowing from the second pump 36 in the direction indicated by arrow F22. The mixture of air and toner T flows within the toner transport path 28 in the direction indicated by arrow F31 towards the vicinity of the relatively low-pressure venting member 26. Then, as in the fifth state of the pump, only air is discharged from the venting member 26 to the outside of the toner transport path 28 in the direction indicated by arrow F32. Therefore, the toner T and air separate from each other. The separated toner T falls into the receiving port 24 of the developing unit B due to gravity and is supplied to the developing unit B.

[0131] As described above, in the sixth pump state, the toner T is transferred to the developing unit B by the airflow generated by the contraction operation of the first pump 35 and the second pump 36. In other words, the toner T is transferred from the first connection port 28a to the second connection port 28b together with the air discharged from the second pump 36.

[0132] As described above, in the second toner supply operation, the discharge of toner T from the discharge port 27 (i.e., pump fifth and pump sixth states) alternates with the cessation of toner T discharge (i.e., pump third and pump fourth states). Then, the toner T discharged into the toner transport path 28 is transported and supplied to the developing unit B by the airflow generated by the first pump 35 and / or the second pump 36.

[0133] C. Third-party toner supply operation

[0134] refer to Figure 13 The third toner supply operation will be described. The third toner supply operation begins when the first pump 35 stops. Timing TL3 is the timing when the first pump 35 stops, i.e., the timing when the second toner supply operation ends and the third toner supply operation begins.

[0135] like Figure 13 As shown, during the third toner supply operation, the toner transport section alternates between the first pump state and the second pump state, as in the first toner supply operation. Furthermore, toner T is not transported from the toner storage unit C to the toner transport path 28, and air in the second pump 36 flows from the toner transport path 28 to the venting member 26 and is discharged to the outside through the venting member 26. Therefore, when toner T remains in the toner transport path 28, the residual toner is transported to the developing unit B through the third toner supply operation.

[0136] As described above, during the third toner supply operation, air that has not been mixed with toner T is supplied to the toner transport path 28 after the second toner supply operation, thereby transporting the residual toner T in the toner transport path 28 to the developing unit B. That is, in this embodiment, air is discharged from the venting member 26 in each of the first, second, and third toner supply operations.

[0137] Timing TL4 is the timer for stopping the second pump 36. After a predetermined time has elapsed following timings TL3 and TL4, the second pump 36 stops, and the third toner supply operation (i.e., a series of toner supply operations) ends.

[0138] As described above, according to the configuration of this embodiment, toner T can be supplied immediately from toner storage unit C based on the amount of toner T consumed by developing unit B in the toner supply operation described above. Furthermore, since the toner T discharged from toner storage unit C is completely supplied to developing unit B, the amount of toner T remaining in toner transport path 28 can be reduced.

[0139] It should be noted that although the image forming apparatus IF according to this embodiment is configured to include a set of toner storage units C and developing units B, the configuration is not limited thereto. For example, the image forming apparatus may include multiple sets of corresponding units, as in a color laser printer.

[0140] According to this disclosure, an image forming apparatus that suppresses image defects can be provided.

[0141] While this disclosure has been described with reference to embodiments, it should be understood that this disclosure is not limited to the disclosed embodiments. The scope of the appended claims is to be given the broadest interpretation in order to cover all such modifications as well as equivalent structures and functions.

Claims

1. An image forming apparatus, comprising: A toner storage unit, the toner storage unit including a first toner receiving portion configured to contain toner therein; Photosensitive components; The developing unit includes a developing member configured to develop an electrostatic latent image formed on the photosensitive member, and a second toner receiving portion configured to receive toner to be supplied to the developing member therein. A toner transport path, the toner transport path being configured to transport the toner from the toner storage unit to the developing unit; A first pump is connected to the first toner container and is configured to inject air to feed the toner in the first toner container toward the toner transport path. as well as A second pump, connected to the toner delivery path and configured to inject air to feed toner in the toner delivery path toward the second toner receiving portion, wherein... The toner delivery path includes a first connection port connected to the first toner container, a second connection port connected to the second toner container, and a third connection port connected to the second pump, wherein... The toner, along with the air injected from the second pump, is transferred from the first connection port to the second connection port.

2. The image forming apparatus according to claim 1, further comprising: A vent, which communicates with the outside, is located in a part of the toner transport path from the midpoint between the first connection port and the second connection port to the second toner receiving portion, or is located in the second toner receiving portion; as well as A venting member configured to allow air to pass through while preventing the toner from passing through, the venting member being configured to cover the vent.

3. The image forming apparatus according to claim 1, wherein: The second pump includes: The volume-changing portion is configured to change its volume. A suction port that allows communication between the volumetric variation portion and the outside of the second pump; An outlet port that allows communication between the volume change portion and the toner transport path. A first valve, configured to switch between an open state allowing air to flow into the volume-changing section through the intake port and a closed state preventing air from flowing out of the volume-changing section through the intake port, and The second valve is configured to switch between an open state that allows air to flow out of the volume change section through the exhaust port and a closed state that prevents air from flowing into the volume change section through the exhaust port.

4. The image forming apparatus according to claim 1, wherein: The first pump includes: The volume-changing portion is configured to change its volume, and The intake and exhaust ports are configured to perform the intake of air into and exhaust of air from the first toner storage section.

5. The image forming apparatus according to claim 2, wherein: The second connection port opens vertically downwards, and The vent is located directly above the second connection port and opens upwards along the vertical direction.

6. The image forming apparatus according to claim 1, wherein: The first connection port is located directly below the toner storage unit and opens vertically upwards.

7. The image forming apparatus according to claim 1, wherein: The first connection port is located vertically below the second connection port.

8. The image forming apparatus according to claim 1, wherein: The toner transport path includes a branch portion, which has a portion connected to the first connection port, a portion connected to the second connection port, and a portion connected to the third connection port.

9. The image forming apparatus according to claim 3, wherein: The pressure performance of the first pump is lower than that of the second pump.

10. The image forming apparatus according to claim 3, further comprising: A vent, which communicates with the outside, is located in a part of the toner transport path from the midpoint between the first connection port and the second connection port to the second toner receiving portion, or is located in the second toner receiving portion; as well as A venting member configured to allow air to pass through while preventing the toner from passing through, the venting member being configured to cover the vent, wherein... When both the first valve and the second valve are open, the ventilation resistance of the ventilation component is greater than the ventilation resistance of the second pump.

11. The image forming apparatus according to any one of claims 1 to 10, further comprising: The control section is configured to control the operation of the first pump and the second pump, and the control section is configured to perform the following operations in sequence as a toner supply operation for supplying the toner from the toner storage unit to the developing unit: a first toner supply operation, wherein only the second pump is operated; a second toner supply operation, wherein both the first pump and the second pump are operated; and a third toner supply operation, wherein only the second pump is operated.

12. The image forming apparatus according to any one of claims 1 to 10, wherein: The first pump is located in the toner storage unit.

13. The image forming apparatus according to any one of claims 1 to 10, further comprising: The main body of the device includes the toner storage unit, the photosensitive component, the developing unit, the toner transport path, the first pump, and the second pump, wherein... The developing unit and the toner storage unit are configured to be attachable to and detachable from the device body.

Images