Powder conveying device and image forming device

Abstract

To prevent the occurrence of clogging in a developer circuit to stabilize discharge of developer to a developing device.SOLUTION: A powder conveying device comprises: a circuit that receives and stores developer from a plurality of toner cartridges filled with the developer, in which the stored developer is circulated and conveyed; a first supply port that supplies the developer onto the circuit; a conveyance path that merges with the circuit on the upstream of the first supply port on the circuit and conveys the developer to supply it into the circuit; a second supply port that supplies powder to the conveyance path; a detection member that detects the developer stored in the circuit; a first conveying member that conveys the developer in the circuit at a first conveyance speed; and a second conveying member that extends to the conveyance path in the circuit and conveys the developer in the circuit at a second conveyance speed faster than the first conveyance speed.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a powder transport device and an image forming apparatus. [Background technology]

[0002] In an image forming apparatus having a toner supply device that supplies toner to one supply destination, multiple suction type single-axis eccentric screw pumps connected in parallel are used as the toner supply device, and the supply destination is a developing device. An image forming apparatus is known (Patent Document 1).

[0003] A developing device is also known in which a developing agent storage section is provided on the second side of the toner feeder, which is formed in a cylindrical shape and has a toner receiving port on a first side at one end and a toner supply port on a second side opposite the first side at the other end, and which is rotatably arranged to include a toner feeder having a toner transport auger inside, a toner cartridge which supplies toner from the toner receiving port into the toner feeder, and a developing device having a toner refill port which opens at a position communicating with the toner supply port, and in which a developer storage section is provided on the second side of the toner feeder facing the toner supply port, with the distance between the first side and the second side being wider than in the adjacent portion (Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2009-69511 A [Patent Document 2] Japanese Patent Application Publication No. 8-190243 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to prevent clogging in the developer circulation path and to stabilize the discharge of developer into a developing device. [Means for solving the problem]

[0006] In order to solve the above problem, the powder conveying device according to claim 1 is a circulation path for receiving and storing developer from a plurality of toner cartridges filled with the developer, and for transporting the stored developer while circulating; On the circulation path From one of the toner cartridges a first supply port for supplying the developer; a conveying path that merges with the circulation path upstream of the first supply port and conveys the developer so as to supply the developer into the circulation path; On the conveying path The other toner or ridge The above Developer A second supply port for supplying a detection member that detects the developer contained in the circulation path; a first transport member that transports the developer in the circulation path at a first transport speed; At least in the region where the conveying path merges with the circulation path a second transport member extending into the transport path within the circulation path and transporting the developer into the circulation path at a second transport speed faster than the first transport speed; It is characterized by:

[0008] Claim 2 The invention described herein is a powder conveying device according to claim 1, the second transport member transports the developer at the second transport speed in a range of the circulation path before a position where the detection member is provided; It is characterized by:

[0009] Claim 3 The invention described herein is as follows: or 2 In the powder conveying device according to the present invention, the second transport speed is equal to or greater than twice the transport speed at which the developer is transported so as to be discharged from the circulation path; It is characterized by:

[0010] Claim 4 The invention described is as follows: 3 13. The powder conveying device according to claim 12, the second transport member is formed to be rotatable integrally with the first transport member, the first transport member having a spiral blade formed with a predetermined spiral pitch relative to an axis and a predetermined gap between the spiral blade and the axis so that the developer can pass through the gap; The above The developer transporting force of the first transporting member is greater than that of the second transporting member. It is characterized by:

[0011] Claim 5 The invention described is as follows: 4 13. The powder conveying device according to claim 12, the circulation path is formed integrally with a guide that guides the insertion and removal of the toner cartridge and holds the toner cartridge above the circulation path; It is characterized by:

[0012] Claim 6 The invention described is as follows: 5 13. The powder conveying device according to claim 12, The powder conveying device is detachably attached to the front side of the image forming apparatus. It is characterized by:

[0013] Claim 7 The invention described is as follows: 6 13. The powder conveying device according to claim 12, one of the plurality of toner cartridges is driven by switching the rotation direction of one driving source; It is characterized by: It is characterized by:

[0014] Claim 8 The invention described is as follows: 7 In the powder conveying device according to the present invention, the first conveying member and the second conveying member are rotationally driven by a driving source different from a driving source of the toner cartridge; It is characterized by:

[0015] In order to solve the above problem, the following claims are provided:9 The image forming apparatus according to the present invention an image carrier on whose surface an electrostatic latent image is formed; a developing device for developing the electrostatic latent image on the image carrier using a developer including at least a toner; The developer in the toner cartridge is supplied to the developing device. 8 and a powder conveying device according to any one of the preceding claims. It is characterized by: Effect of the Invention

[0016] According to the invention as set forth in claims 1 and 10, clogging of the developer in the circulation path can be suppressed, and the discharge of the developer can be stabilized.

[0018] Claim 2 According to the invention described in the above, the detection of the developer can be stabilized.

[0019] Claim 3 According to the invention described in the above, it is possible to suppress the accumulation of developer at the joining portion of the circulation path and the transport path, and to stabilize the discharge of the developer.

[0020] Claim 4 According to the invention described in the above, the developer can be transported without being accumulated at the joining portion of the circulation path and the transport path.

[0021] Claim 5、 According to the invention described in claim 6, maintenance and replacement of the powder conveying device can be easily performed.

[0022] Claim 7 According to the invention described above, the toner cartridge can be driven with an inexpensive configuration.

[0023] Claim 8 According to the invention described in the above, the first conveying member and the second conveying member can be driven with an inexpensive configuration. [Brief description of the drawings]

[0024] [Figure 1] 1 is a schematic cross-sectional view illustrating an example of a schematic configuration of an image forming apparatus. [Diagram 2] FIG. 2 is a schematic vertical cross-sectional view showing a photoconductor unit, a developing device, and a powder transport device. [Diagram 3] 3A and 3B are schematic cross-sectional views illustrating transport of developer in the developing device. [Figure 4] FIG. 2 is a schematic vertical cross-sectional view showing the configuration of the powder conveying device. [Diagram 5] FIG. 2 is a cross-sectional view showing the internal configuration of the reserve tank. [Figure 6] 4A and 4B are diagrams illustrating specific configuration examples of a first transport auger and a second transport auger. [Figure 7] 5A and 5B are schematic plan views illustrating transport and circulation of developer in a reserve tank. [Figure 8] FIG. 13 is a diagram for explaining the transmission of driving force of the powder transport device from the perspective of the rear side. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The present invention will be described in more detail below with reference to the drawings, showing embodiments and specific examples, but the present invention is not limited to these embodiments and specific examples. In addition, in the following explanation using the drawings, it should be noted that the drawings are schematic and the ratios of the dimensions, etc. may differ from the actual ones, and in order to make it easier to understand, illustrations other than those of parts necessary for the explanation have been omitted as appropriate. For ease of understanding in the following description, in the drawings, the front-rear direction is defined as the X-axis direction, the left-right direction as the Y-axis direction, and the up-down direction as the Z-axis direction.

[0026] (1) Overall Configuration and Operation of Image Forming Apparatus (1.1) Overall configuration of image forming apparatus FIG. 1 is a schematic cross-sectional view showing an example of a schematic configuration of an image forming apparatus 1 according to the present embodiment. The image forming apparatus 1 is configured to include an image forming section 10, a paper feeding device 20 attached to one end of the image forming section 10, a paper discharge section 30 provided at the other end of the image forming section 10 and from which printed paper is discharged, and an image processing section 40 (not shown) that generates image information from printing information transmitted from a higher-level device.

[0027] The image forming unit 10 is configured with a system control device 11 (not shown), an exposure device 12, a photosensitive unit 13, a developing device 14, a transfer device 15, paper transport devices 16a, 16b, 16c, a fixing device 17, and a drive device 18 (not shown), and forms the image information received from the image processing unit 40 as a toner image on paper fed from the paper feed device 20.

[0028] The paper feed device 20 supplies paper to the image forming unit 10. That is, the paper feed device 20 is provided with a plurality of paper stacking units that store paper P of different types (e.g., different materials, thicknesses, paper sizes, and paper grains), and is configured to supply paper fed from any one of the plurality of paper stacking units to the image forming unit 10.

[0029] The paper discharge section 30 discharges the paper on which an image has been output by the image forming section 10. To this end, the paper discharge section 30 is provided with a paper discharge storage section into which the paper after the image has been output is discharged. The paper discharge section 30 may also have a function of performing post-processing such as cutting and stapling on the paper stack output from the image forming section 10.

[0030] (1.2) Configuration and operation of the image forming unit In the image forming apparatus 1 configured as above, paper is fed from a paper stacking unit of the paper feeder 20 designated for each sheet to be printed in a print job to the image forming unit 10 in accordance with the timing of image formation.

[0031] The photoreceptor unit 13 includes photoreceptor drums 31 as image carriers that are arranged in parallel and rotated below the exposure devices 12. Along the rotation direction of the photoreceptor drums 31, a charging roll 32, the exposure devices 12, the developing devices 14, a primary transfer roll 52, and a cleaning blade 34 are arranged.

[0032] The developing device 14 has a developing housing 41 that contains a developer therein. A developing roll 42 is disposed in the developing housing 41 so as to face the photosensitive drum 31, and a regulating member 45 (see FIG. 2) that regulates the layer thickness of the developer is disposed adjacent to the developing roll 42. The developing devices 14 are configured in substantially the same manner except for the developer contained in a developing housing 41, and form toner images of yellow (Y), magenta (M), cyan (C), and black (K), respectively.

[0033] Above the developing device 14, there are disposed replaceable toner cartridges T that contain developer (toner containing carrier), and a powder conveying device 100 that supplies developer from each toner cartridge T to the developing device 14. In this embodiment, yellow (Y), magenta (M), and cyan (C) toner cartridges Ty, Tm, and Tc, and two black (K) toner cartridges Tk are detachable.

[0034] The surface of the rotating photoconductor drum 31 is charged by the charging roll 32, and an electrostatic latent image is formed on it by latent image forming light emitted from the exposure device 12. The electrostatic latent image formed on the photoconductor drum 31 is developed into a toner image by the developing roll 42.

[0035] The transfer device 15 is configured to include an intermediate transfer belt 51 onto which the toner images of each color formed on the photosensitive drum 31 of each photosensitive unit 13 are multiple-transferred, a primary transfer roll 52 which sequentially transfers (primary transfer) the toner images of each color formed on each photosensitive unit 13 onto the intermediate transfer belt 51, and a secondary transfer roll 53 which collectively transfers (secondary transfer) the toner images of each color transferred in a superimposed state onto the intermediate transfer belt 51 onto a recording medium, i.e., paper.

[0036] The color toner images formed on the photosensitive drum 31 of each photosensitive unit 13 are electrostatically transferred (primary transfer) sequentially onto the intermediate transfer belt 51 by a primary transfer roll 52 to which a predetermined transfer voltage is applied from a power supply device (not shown) controlled by the system control device 11, and a superimposed toner image in which the color toners are superimposed is formed.

[0037] The superimposed toner image on the intermediate transfer belt 51 is transported to a secondary transfer portion TR where the secondary transfer roll 53 is arranged in pressure contact with the backup roll 65 via the intermediate transfer belt 51 as the intermediate transfer belt 51 moves. When the superimposed toner image is transported to the secondary transfer portion TR, a sheet is supplied to the secondary transfer portion TR from the sheet feeder 20 in time with the transport. A predetermined secondary transfer voltage is applied from a power supply device controlled by the system control device 11 to a backup roll 65 that faces the secondary transfer roll 53 across the intermediate transfer belt 51, and the multiple toner images on the intermediate transfer belt 51 are collectively transferred onto the sheet.

[0038] Residual toner on the surface of the photoconductor drum 31 is removed by a cleaning blade 34 and collected in a waste toner container (not shown). The surface of the photoconductor drum 31 is recharged by a charging roll 32.

[0039] The fixing device 17 has an endless fixing belt 17a that rotates in one direction, and a pressure roll 17b that contacts the peripheral surface of the fixing belt 17a and rotates in one direction, and a nip portion (fixing area) is formed by the pressure contact area between the fixing belt 17a and the pressure roll 17b. The paper onto which the toner image has been transferred in the transfer device 15 is transported via the paper transport device 16a to the fixing device 17 without the toner image being fixed thereon. The toner image on the paper transported to the fixing device 17 is fixed thereon by the action of pressure and heat by a pair of a fixing belt 17a and a pressure roll 17b.

[0040] The paper on which the fixing has been completed is sent to the paper discharge section 30 via the paper transport device 16b. When images are to be output on both sides of the paper, the paper is turned over by the paper transport device 16c and sent again to the secondary transfer unit TR in the image forming unit 10. Then, after the toner image is transferred and the transferred image is fixed, the paper is sent to the paper discharge unit 30. The paper sent to the paper discharge unit 30 is subjected to post-processing such as cutting and stapling as necessary, and then discharged to the paper discharge storage unit.

[0041] (2) Main components and operation Figure 2 is a schematic vertical cross-sectional view showing the photosensitive unit 13, the developing device 14 and the powder conveying device 100, Figure 3 is a schematic cross-sectional view explaining the transport of developer in the developing device 14, Figure 4 is a schematic vertical cross-sectional view showing the configuration of the powder conveying device 100, Figure 5 is a cross-sectional view showing the internal configuration of the reserve tank 110, and Figure 6 is a front view showing a specific example configuration of the first conveying auger 112 and the second conveying auger 113. The configuration and operation of the powder conveying device 100 will be described below with reference to the drawings.

[0042] (2.1) Photoconductor unit The photosensitive unit 13 has a photosensitive drum 31 supported for free rotation in a unit housing 35, and within the unit housing 35 are arranged a charging roll 32, a cleaning roll 33, a cleaning blade 34, and a transport auger 36 that transports the toner removed by the cleaning blade 34 to a waste toner collection container (not shown).

[0043] (2.2) Developing device 2, in the developing device 14, a developing roll 42 is rotatably supported in a developing housing 41, and an agitating auger 43A, a supply auger 43B, and a regulating member 45 are arranged in the developing housing 41. The developer is filled around the agitating auger 43A and the supply auger 43B in the developing housing 41, and is closed by a cover member 44.

[0044] The developing roll 42 is disposed to face the outer circumferential surface of the photosensitive drum 31 through an opening 41a formed in the developing housing 41. The developing roll 42 is formed in a cylindrical shape and disposed to extend along a direction (shown in FIG. 3) from the front side to the back side of the image forming apparatus 1. The developing roll 42 also includes a cylindrical developing sleeve 42A rotatably supported by the developing housing 41, and a magnet 42B as a cylindrical magnetic member provided in the internal space of the developing sleeve 42A and fixed to the developing housing 41. The developing sleeve 42A is configured such that the developer is held on its outer peripheral surface by the magnetic force of the magnet 42B, and the developer is transported and supplied to the electrostatic latent image on the photosensitive drum 31 by the rotation of the developing sleeve 42A (indicated by arrow B in FIG. 2).

[0045] The developing device 14 is also provided with an agitating auger 43A and a supply auger 43B that agitate and transport the developer. As shown in Fig. 3, a partition wall 41b is provided between the agitating auger 43A and the supply auger 43B in the developing housing 41, dividing the developing housing 41 into two developer accommodating sections 41A and 41B, and openings 41C and 41D are formed at both longitudinal ends of the partition wall 41b, respectively.

[0046] The agitating auger 43A and the supply auger 43B receive a rotational force from a drive source (not shown) and rotate along the inner walls of the developer containing portions 41A and 41B, thereby transporting the developer in a predetermined direction within the developer containing portions 41A and 41B. Specifically, stirring auger 43A transports the developer in developer container 41A in the direction of arrow (-Y) (toward the front) while stirring, and supply auger 43B transports the developer in developer container 41B in the direction of arrow (Y) (toward the back) while stirring. The developer transported in the direction of arrow (-Y) moves from opening 41C to developer container 41B, and the developer transported in the direction of arrow (Y) moves from opening 41D to developer container 41A. As a result, the developer in the developing housing 41 is circulated while being agitated by the two agitating augers 43A and the supply auger 43B. The toner in the developer is charged by the agitation of the developer in this manner.

[0047] One end side (Y direction: rear side) of the developing housing 41 is provided with an inlet 47 (schematically shown in FIG. 3 for explaining the function) for receiving the developer supplied from the powder conveying device 100. The toner received by the developing device 14 at the inlet 47 is conveyed by the stirring auger 43 to move to the developer accommodating section 41A of the developing housing 41 and is mixed with the developer.

[0048] The developer supplied from the powder conveying device 100 through the receiving port 47 is conveyed from the rear side (Y direction) to the front side (-Y direction) while being stirred by the stirring auger 43A, and is moved to the supply auger 43B at the front side (-Y direction). The developer supplied from the supply auger 43B is then supplied to the developing roll 42.

[0049] (2.3) Powder conveying device The powder conveying device 100 is composed of a reserve tank 110 that temporarily stores the developer received from the toner cartridge Tk and supplies it to the developing device 14, a cartridge guide 120 that guides the insertion and removal of the toner cartridge T and holds the installed toner cartridge Tk above the reserve tank 110, and a supply path 130 that conveys the developer from the toner cartridge Tk held by one of the cartridge guides 120 to the reserve tank 110.

[0050] In this embodiment, as shown in Fig. 4, in the powder conveying device 100 for black (K), two toner cartridges Tk are detachably attached to the cartridge guide 120. From the toner cartridge Tk located above the reserve tank 110, developer is directly supplied from a first supply port 110A (to be described later), and from the toner cartridge Tk located to the side of the reserve tank 110, developer is supplied from a second supply port 110B (to be described later) via a supply path 130 having a conveying auger 131. The powder conveying devices 100 for yellow (Y), magenta (M), and cyan (C) do not have a supply path 130 because one toner cartridge Ty, Tm, and Tc are detachably attached to each of them. The following describes the black (K) powder transport device 100 that receives developer from two toner cartridges Tk.

[0051] As shown in FIG. 5, the reserve tank 110 includes a tank body 111 that receives the developer filled in the toner cartridge Tk and stores the developer, a first transport auger 112 that is rotatably arranged inside the tank body 111 and serves as an example of a first transport member that rotates to transport the developer, a second transport auger 113 that is an example of a second transport member, and a developer detection sensor 114 that serves as an example of a detection member that detects the developer stored in the tank body 111.

[0052] The tank body 111, which is generally box-shaped, has a partition wall 111a standing in the center, dividing it into two developer storage sections 111A and 111B, and openings 111C and 111D are formed at both longitudinal ends of the partition wall 111b, respectively. The developer accommodating section 111A rotatably houses a first transport auger 112 and a second transport auger 113, forming one side of a circulation path for circulating the developer. The developer accommodating section 111B rotatably houses a coil auger 115 formed by spirally winding a metal wire, forming the other side of the circulation path for accommodating and transporting the developer delivered from the developer accommodating section 111A through an opening 111C. In this embodiment, the developer accommodating section 111A and the developer accommodating section 111B are connected at both ends by openings 111C and 111D, forming the circulation path for the developer.

[0053] The tank body 111 is covered with a lid body having a first supply port 110A (shown by a dashed line in FIG. 5) for receiving developer from one of the toner cartridges Tk in the middle of the developer containing portion 111A, and contains the developer therein.

[0054] A transport path 117 is connected to one end of the tank body 111, which receives developer supplied from the other toner cartridge Tk, merges with the developer storage unit 111A, and transports the developer into the circulation path. A second supply port 110B (shown by a dashed line in FIG. 5) is provided at one end of the transport path 117, which receives developer supplied from the other toner cartridge Tk and transported through the supply path 130. That is, the transport path 117 straddles the side wall of the tank body 111, merges with the developer storage unit 111A, which is one of the circulation paths inside the tank body 111, and transports the developer supplied from the other toner cartridge Tk into the tank body 111. The inner diameter of the through hole 111c provided in the side wall of the tank body 111 to connect the transport path 117 to the developer accommodating portion 111A is smaller than the inner diameter of the developer accommodating portion 111A. This prevents the developer from flowing back from the developer accommodating portion 111A to the transport path 117.

[0055] A developer detection sensor 114 for detecting the amount of developer contained in the developer container 111A is disposed downstream of the first supply port 110A of the tank body 111. The developer detection sensor 114 has a movable piece 114a rotatably attached to a rotating shaft 114b, and detects the presence or absence of developer with an optical sensor SNR disposed at the end of the rotating shaft 114b. The developer detection sensor 114 can also be disposed without being exposed from the side wall of the tank body 111 by using a highly sensitive inductance type sensor.

[0056] A first transport auger 112 and a second transport auger 113 formed in a spiral shape are rotatably provided around a rotation axis in the developer storage section 111A, which is one of the circulation paths of the tank body 111. A coil auger 115 is rotatably provided in the developer storage section 111B, which is the other of the circulation paths of the tank body 111.

[0057] Furthermore, an auxiliary transport auger 116 is rotatably provided inside the partition wall 111a between the first transport auger 112 and the coil auger 115 in a plan view. The auxiliary transport auger 116 has a paddle 116A at one end that transfers developer between the first transport auger 112 and the coil auger 115 at an opening 111C (see arrow A in FIG. 7), and sends the circulating developer to the discharge port 110C with a spiral blade 116B formed on the opening 111D side at the other end (see arrow B in FIG. 7). At the boundary between the opening 111D and the developer storage section 111A, a partition wall 111b that is lower in height than the partition wall 111a is provided to suppress backflow of the developer in the circulating direction.

[0058] FIG. 6 shows a specific example of the configuration of the first transfer auger 112 and the second transfer auger 113. As shown in FIG. The first transport auger 112 is formed with a spiral blade 112a having a predetermined gap S with respect to the shaft 112b. Specifically, the shaft 112b and the blade 112a are connected by a support portion 112c so as to maintain the gap S substantially equal to the blade height H. This allows the developer transported by the first transport auger 112 through the developer storage unit 111A to pass through the gap S, and the transport speed of the developer is slower than that of a transport auger in which the spiral blade does not have a gap with respect to the shaft.

[0059] The second transport auger 113 is a resin auger having a spiral blade 113a on the outer periphery of a shaft 113b with a spiral pitch P2 longer than the spiral pitch P1 of the first transport auger 112, and the outer diameter of the blade 113a in a direction intersecting with the shaft 113b is formed to be substantially the same as that of the first transport auger 112. Therefore, the transport speed V2 of the developer of the second transport auger 113 is faster than the transport speed V1 of the first transport auger 112. Furthermore, since the outer diameter of the second transport auger 113 is formed to be larger than the outer diameter of the spiral blade 116B of the auxiliary transport auger 116, the transport speed V2 of the developer of the second transport auger 113 is faster than the speed at which the auxiliary transport auger 116 sends the developer to the discharge port 110C, specifically, it is more than twice as fast. Further, the transport speed V2 of the second transport auger 113 is nearly twice as fast as the transport speeds of the transport members in the circulation path, that is, the first transport auger 112, the coil auger 115, and the auxiliary transport auger 116. That is, in the developer circulation path, the developer transport speed V2 of the second transport auger 113 is the fastest.

[0060] 5, the second transport auger 113 thus configured is disposed extending from the developer storage portion 111A, which is one of the circulation paths of the tank body 111, to the transport path 117. Specifically, it is disposed from the position where the second supply port 110B is provided to the position where the first supply port 110A is provided, penetrating the side wall of the tank body 111, and transports the developer supplied from the second supply port 110B so as to draw it into the tank body 111, while increasing the developer transport force at the junction of the circulation paths to suppress stagnation of the developer. For this reason, the second transport auger 113 is disposed over at least the entire area where the transport path 117 joins the circulation path, and transports the developer at a transport speed V2 that is faster than the transport speed V1 of the first transport auger 112. It is preferable that the second transport auger 113 is disposed in a range in front of the position where the developer detection sensor 114 is provided. This makes it possible to prevent the developer from stagnating in front of the developer detection sensor 114, and to stabilize the developer detection.

[0061] The coil auger 115 is a transport auger in which a metal wire is wound in a spiral shape with a spiral pitch P3 smaller than that of the first transport auger 112, and the transport speed of the developer is set slower than the transport speed V1 of the first transport auger 112. For this reason, the developer is temporarily stored in the developer storage unit 111B while being stirred, and the reserve tank 110 is endowed with a reserve function for the developer to be supplied to the developing device 14. This makes it possible to replace the toner cartridge T in an operating state without stopping the device during continuous printing, particularly in a high-speed image forming device.

[0062] (2.4) Function of powder conveying device FIG. 7 is a schematic plan view illustrating the transport and circulation of the developer in the reserve tank 110. As shown in FIG. In the powder conveying device 100 according to this embodiment, the developer supplied from one toner cartridge Tk flows from the first supply port 110A into the developer accommodating portion 111A of the tank body 111. The developer supplied from the other toner cartridge Tk is conveyed through the supply path 130, received by the conveying path 117 from the second supply port 110B, and conveyed through the conveying path 117 to flow into the junction of the developer accommodating portion 111A.

[0063] In this way, when the developer flows from the transport path 117 to join the circulation path, the developer may temporarily accumulate and cause clogging at the through hole 111c and the second supply port 110B which are the connection parts between the transport path 117 and the tank body 111. In addition, there is a risk that the developer may backflow at the joining part, causing the backflow developer to be unintentionally supplied to the developing device 14.

[0064] In the reserve tank 110 of this embodiment, the second transport auger 113, which is arranged extending from the developer storage section 111A, which is one of the circulation paths of the tank body 111, to the transport path 117, is configured to have a faster transport speed than the first transport auger 112, which is arranged downstream in the circulation path. Specifically, the second transport auger 113 transports the developer at a transport speed V2 faster than the transport speed V1 of the first transport auger 112 at least in the entire area where the transport path 117 joins the circulation path (range R1 in FIG. 7). This prevents the developer from accumulating at the joining portion, making it difficult for clogging to occur, and enables a stable supply of developer to the developing device 14. In particular, the second transport auger 113 transports the developer at a transport speed V2 faster than the transport speed V1 of the first transport auger 112 in a range (range R2 in FIG. 7) in front of the position where the developer detection sensor 114 is provided, thereby preventing the developer from stagnating in front of the developer detection sensor 114 and stabilizing developer detection.

[0065] (3) Driving the powder conveying device FIG. 8 is a diagram for explaining the transmission of driving force of the powder transport device 100 from the perspective of the rear side. 8, the powder conveying device 100 is configured such that the reserve tank 110, the cartridge guide 120, and the supply path 130 are integrally formed, and the powder conveying device 100 is provided with a first motor M1 that drives the reserve tank 110 and the supply path 130, and a second motor M2 that drives the two toner cartridges Tk. The drive device including the first motor M1 and the second motor M2 is disposed at the rear side of the powder conveying device 100, and the powder conveying device 100 is detachable from the front side of the image forming apparatus 1.

[0066] In the reserve tank 110, a first conveying auger 112, a second conveying auger 113, and an auxiliary conveying auger 116 are rotatably supported by a tank body 111, and are rotationally driven by a first motor M1 via a gear train mechanism consisting of a plurality of gears. Of the two toner cartridges Tk rotatably mounted on the cartridge guide 120, one of the toner cartridges Tk is rotated by switching the rotation direction of the second motor M2. In this way, in the powder conveying device 100, the reserve tank 110 and the toner cartridge Tk are driven by separate motors, and the two toner cartridges Tk that do not need to be driven simultaneously are driven by a single motor (the second motor M2) by switching the rotation direction, thereby realizing an inexpensive configuration. [Explanation of symbols]

[0067] 1. Image forming device 10. Image forming section 11 System control device 12. Exposure equipment 13 Photoconductor unit 14. Developing device 15...Transfer device 17 Fixing device 18. Drive unit 20...Paper feed device 30....Paper ejection section 40...Image processing unit 100 Powder conveying device 110···Reserve tank 111 tank body, 112 first conveying auger, 113 second conveying auger, 114 developer detection sensor, 115 coil auger, 116 auxiliary conveying auger, 117 conveying path 120 Cartridge guide 130...supply route

Claims

1. a circulation path for receiving and storing developer from a plurality of toner cartridges filled with the developer, and for transporting the stored developer while circulating; a first supply port for supplying the developer from one of the toner cartridges onto the circulation path; a conveying path that merges with the circulation path upstream of the first supply port and conveys the developer so as to supply the developer into the circulation path; a second supply port for supplying the developer from the other toner cartridge to the transport path; a detection member that detects the developer contained in the circulation path; a first transport member that transports the developer in the circulation path at a first transport speed; a second transport member extending into the transport path within the circulation path at least in a region where the transport path merges with the circulation path, and transporting the developer into the circulation path at a second transport speed faster than the first transport speed; A powder conveying device characterized by:

2. the second transport member transports the developer at the second transport speed in a range of the circulation path before a position where the detection member is provided; 2. The powder transport device according to claim 1 .

3. the second transport speed is equal to or greater than twice the transport speed at which the developer is transported so as to be discharged from the circulation path; 3. The powder transport device according to claim 1 or 2.

4. the second transport member is formed so as to be rotatable integrally with the first transport member, the first transport member having a spiral blade formed with a predetermined spiral pitch relative to an axis and a predetermined gap between the spiral blade and the axis so that the developer can pass through the gap, and has a developer transport force greater than that of the first transport member; 4. The powder transport device according to claim 1, wherein the powder transport device is a powder transport device.

5. the circulation path is formed integrally with a guide that guides the insertion and removal of the toner cartridge and holds the toner cartridge above the circulation path; 5. The powder transport device according to claim 1, wherein the powder transport device is a powder transport device.

6. The powder conveying device is detachably attached to the front side of the image forming apparatus.

6. The powder transport device according to claim 1, wherein the powder transport device is a powder transport device.

7. one of the plurality of toner cartridges is driven by switching the rotation direction of one driving source; 7. The powder transport device according to claim 1, wherein the powder transport device is a powder transport device.

8. the first conveying member and the second conveying member are rotationally driven by a driving source different from a driving source of the toner cartridge; 8. The powder transport device according to claim 7.

9. an image carrier on whose surface an electrostatic latent image is formed; a developing device for developing the electrostatic latent image on the image carrier using a developer including at least a toner; and the powder conveying device according to claim 1 , which supplies the developer in the toner cartridge to the developing device.

1. An image forming apparatus comprising:

Images