WO2023146646A1

WO2023146646A1 - Image forming apparatus with airflow path for cleaner of photoreceptor device

Info

Publication number: WO2023146646A1
Application number: PCT/US2022/052554
Authority: WO
Inventors: Naoya Iwata
Original assignee: Hewlett-Packard Development Company, L. P.
Priority date: 2022-01-27
Filing date: 2022-12-12
Publication date: 2023-08-03

Abstract

An image development device includes a developing device to store a developer, a photoreceptor device including a photoreceptor to form a toner image and a cleaner to remove an excess toner remaining on a surface of the photoreceptor, a first airflow path connecting the developing device to the cleaner, and a second airflow path connecting the cleaner to the developing device.

Description

IMAGE FORMING APPARATUS WITH AIRFLOW PATH FOR CLEANER OF

PHOTORECEPTOR DEVICE

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

[0001] This application claims priority to Japan Patent Application No. 2022-011007, filed on January 27, 2022, the entirety of which is incorporated by reference herein.

BACKGROUND

[0002] An image forming apparatus includes a developing device which stirs a developer and a photoreceptor device which has a photoreceptor forming a toner image from a toner in the developer. The developing device includes a developing roller which holds the stirred developer. The photoreceptor device includes a cleaner which removes an excess toner remaining on a surface of the photoreceptor.

BRIEF DESCRIPTION OF THE DRAWINGS

[0003] FIG. 1 is a schematic view of an image forming apparatus, according to an example.

[0004] FIG. 2 is a schematic cross-sectional view of an image development device of an image forming apparatus according to an example, which includes a developing device and a photoreceptor device.

[0005] FIG. 3 is a front perspective view of the image development device.

[0006] FIG. 4 is a rear perspective view of the image development device.

[0007] FIG. 5 is a schematic diagram of a cleaner of the photoreceptor device, illustrating an end portion of a toner conveying path of the cleaner and a first airflow path connected to the toner conveying path. [0008] FIG. 6 is a graph showing experimental results of a toner conveying property in an image forming apparatus according to an example, having a first airflow path and a second airflow path, and in an image forming apparatus having no first and second airflow paths.

[0009] FIG. 7 is a graph showing an internal pressure of the image forming apparatus according to the example with the first airflow path and the second airflow path and an internal pressure of the image forming apparatus having no first and second airflow paths.

[0010] FIG. 8 is a graph showing an example of a relationship between an internal pressure of the image forming apparatus and an excess discharge ratio of the developer.

[0011] FIG. 9 is a schematic cross-sectional view of an image development device including a developing device and a photoreceptor device according to another example.

[0012] FIG, 10 is a diagram illustrating a conveying member for a cleaner of the photoreceptor device according to the example of FIG. 9.

[0013] FIG. 11 is a schematic diagram illustrating an end portion of a toner conveying path of the cleaner and an example of a first airflow path connected to the toner conveying path, in the photoreceptor device of FIG. 9.

[0014] FIG. 12 is a rear perspective view of the image development device according to the example of FIG. 9.

DETAILED DESCRIPTION

[0015] In the following description, with reference to the drawings, the same reference numbers are assigned to the same components or to similar components having the same function, and overlapping description is omitted.

[0016] An image forming apparatus according to examples of the present disclosure includes a first airflow path which connects a storing region of a developing device to a cleaner of a photoreceptor device and a second airflow path which connects the cleaner to a conveying region of the developing device. The developing device includes a developing roller holding a developer in the storing region and when the developing roller holds the developer in a rotation state, an internal pressure of the storing region exceeds an internal pressure of the cleaner. According to examples of the image forming apparatus, air may be supplied from the storing region to the cleaner through the first airflow path due to a pressure difference between an internal pressure of the storing region and an internal pressure of the cleaner. Hereinafter, examples of such image forming apparatus will be described.

[0017] FIG. 1 is a diagram schematically showing an example of an image forming apparatus. An image forming apparatus 1 shown in FIG. 1 is an apparatus that may form a color image using the colors of cyan, magenta, yellow, and black The image forming apparatus 1 includes a conveying device 10 which conveys a sheet 5 as a print medium, developing devices 20C, 20M, 20Y, and 20K which develop electrostatic latent images with toner of the respective colors, a transfer device 30 which transfers a layered toner image to the sheet 5, and photoreceptor devices 40C, 40M, 40Y, and 40K which include image carriers such as photoreceptors 41 C, 4 IM, 41Y, and 41 K that form the respective latent images to be developed. Any one of the developing devices 20C, 20M, 20Y, and 20K may be referred to herein as "developing device 20", any one of the photoreceptor devices 40C, 40M, 40Y, and 40K may be referred to herein as "photoreceptor device 40", and any one of the photoreceptors 41C, 4 IM, 41 Y, and 4 IK maybe referred to herein as "photoreceptor 41”. The developing device 20C and the adjacent photoreceptor devices 40C form an image development device 80 including a first airflow path 71 and a second airflow path 72, that will be described further below with reference to other figures. Similarly, the other developing devices 20M, 20Y, and 20K and respectively adjacent photoreceptor devices 40M, 40Y, and 40K form respective image development devices substantially identical to the image development device 80. Further, tire image forming apparatus 1 includes a fixing device 50 which fixes the layered toner image to the sheet 5, and a discharge device 60 which discharges the sheet 5 from the image forming apparatus I .

[0018] Tire conveying device 10 conveys the sheet 5 as the print medium on which an image is to be formed on a conveying path 12. The sheet 5 is stacked in a cassette 7 and is picked up and conveyed by a feeding roller 1 I. Namely, when an image signal of an image to be printed is input into the image forming apparatus 1, a control device (or controller) of the image forming apparatus 1 causes the feeding roller 11 to rotate in order to pick up and convey the sheet 5 from the stack of sheets in the cassette 7. The conveying device 10 conveys the sheet 5 to reach a transfer region 13 through the conveying path 12 at a timing at which the toner image to be transferred to the sheet 5 reaches the transfer region 13.

[0019] The developing devices 20C, 20M, 20Y, and 20K are provided respectively for the four colors. Each developing device 20 includes a developing roller 21 which develops a toner image on the photoreceptor 41. In the developing device 20, a two-component developer containing a toner and a carrier is used as the developer. In the developing device 20, the toner and the carrier are adjusted to a target mixing ratio. When the toner and tire carrier are mixed and stirred, the toner is dispersed and the developer is adjusted to a targeted charge amount.

[0020] In the developing device 20 that uses the two-component developer, a trickle discharge method is adopted to extend the life of the developer. The trickle discharge method is a method of supplying a new carrier to the developing device 20 and discharging an old developer from the developing device 20 to the outside of the developing device 20 when supplying the toner. The trickle discharge method is also referred to as a tri ckle development method or Auto Developer Refill (ADR). In the present disclosure, the "developer” indicates the developer containing both the toner and the carrier.

[0021] The developing roller 21 of the developing device 20 carries the developer. Then, when the developer is conveyed to the developing region facing the photoreceptor 41 with the rotation of the developing roller 21 , the toner contained in the developer carried on tire developing roller 21 transfers to the electrostatic latent image formed on the surface of the photoreceptor 41 to develop the electrostatic latent image. Accordingly, the toner image is formed on the surface of the photoreceptor 41. [0022] The transfer device 30 conveys the toner image formed by the developing device 20 to the transfer region 13 where the toner image is to be secondarily transferred to the sheet 5. Tire transfer device 30 includes a transfer belt 31 which is an endless belt to which the toner image is primarily transferred from the rotating photoreceptor 41, a suspension roller 34 which tensions the transfer belt 31, idler rollers 35 and 36, a drive roller 37 which drives the transfer belt 31, primary transfer rollers 32C, 32M, 32Y, and 32K, and a secondary transfer roller 33 The transfer belt 31 is interposed between the primary transfer rollers 32C, 32M, 32Y, and 32K and the respective photoreceptors 41 C, 41M, 41Y, and 41K to primarily transfer the toner images from the photoreceptors 41C, 41 M, 41 Y, and 41 K onto the transfer belt 31. The toner images formed on the photoreceptor 41 are sequentially layered on the transfer belt 31 to form a single layered toner image. The transfer belt 31 is additionally interposed between secondary transfer roller 33 to secondarily transfer the layered toner image to the sheet 5 in the transfer region 13.

[0023] The photoreceptors 41C, 4 IM, 41 Y, and 4 IK are rotatable. The photoreceptor 41 is referred to as an electrostatic latent image carrier or a photoreceptor drum. The photoreceptors 41C, 41M, 41 Y, and 41K are provided respectively for the four colors. The photoreceptors 41 are arranged along the movement or con veyance direction of the transfer belt 31. The photoreceptor device 40 includes, for example, the photoreceptor 41, a charging device 42, and a cleaner (e.g., cleaning device) 45, The developing device 20, the charging device 42, the exposure device 43, and the cleaner 45 are provided at the positions facing the surface of the photoreceptor 41.

[0024] The charging device 42 is, for example, a charging roller which is in contact with the photoreceptor 41. The charging device 42 charges the surface of the photoreceptor 41 to a predetermined potential. The exposure device 43 exposes the surface of the photoreceptor 41 charged by the charging device 42 in response to the image to be formed on the sheet 5.

Namely, the exposure device 43 irradiates the surface of the photoreceptor 41 with a laser beam to form the electrostatic latent image based on an input image signal. Accordingly, the potential of the portion exposed by the exposure device 43 in the surface of the photoreceptor 41 changes to form the electrostatic latent image on the surface of the photoreceptor 41.

[0025] Tire developing devices 20C, 20M, 20Y, and 20K are respectively supplied with toner from toner tanks 18C, 18M, 18Y, and 18K. Any one of the toner tanks 18C, 18M, 18Y, and 18K may be referred to herein as "toner tank 18". The toner tanks 18C, I8M, 18Y, and 18K respectively store cyan, magenta, yellow, and black toners. The toner is supplied from the toner tank 18 to the associated developing device 20. The developing device 20 develops the electrostatic latent image formed on the photoreceptor 41 with the toner supplied from the associated toner tank 18 to generate the toner image. The cleaner 45 collects the toner remaining on the photoreceptor 41. The cleaner 45 will be further described below.

[0026] The fixing device 50 fixes the layered toner image to the sheet 5 by guiding the sheet 5 to pass through a fixing nip region for heating and pressing the sheet. The fixing device 50 includes a heating roller 52 which heats the sheet 5 and a pressing roller 54 which presses and rotationally drives the heating roller 52. The fixing nip region is provided between the heating roller 52 and the pressing roller 54. The discharge device 60 includes discharge rollers 62 and 64 which receives the sheet 5 to which the toner image has been fixed so as to discharge the sheet 5 to the outside of the image forming apparatus 1.

[0027] FIG. 2 is a diagram showing an example of the image development device 80 including the developing device 20 and the photoreceptor device 40. As shown in FIG. 2, the developing device 20 includes a storing region 20A to store the developer and a conveying region 20B to convey the developer to the storing region 20A. The storing region 20A is provided above the conveying region 20B. The developing device 20 includes a supply auger 22 which supplies the developer to the developing roller 21 and an admix auger 23 which extends in parallel to the supply auger 22 and is disposed below the supply auger 22 in addition to the developing roller 21. The supply auger 22 and the admix auger 23 form a stirring and conveying member that conveys the developer while stirring the developer. [0028] The developing roller 21 and the supply auger 22 are stored in the storing region 20 A of the developing deGee 20. The admix auger 23 is stored in the conveying region 20B of the developing device 20. The developing device 20 includes a wall portion 24 which partitions the storing region 20A and the conveying region 20B and an opening which is located at the end portion of the wall portion 24 in the axial directi on of the supply auger 22 (in the direction of the view of FIG. 2) and the developer of the conveying region 20B moves to the storing region 20A through the opening.

[0029] However, since the developer conveyed by the admix auger 23 is more easily accumulated in the lower portion of the opening, high airtightness is ensured between the storing region 20A and the conveying region 20B. The developer stirred by the supply auger 22 in the storing region 20 A is held by the developing roller 21. The photoreceptor 41 of the photoreceptor device 40 faces the developing roller 21 and the developer held by the developing roller 21 transfers to the surface of the photoreceptor 41.

[0030] FIG. 3 is a front perspective view showing the image development device 80 including the developing device 20 and the photoreceptor device 40. As shown in FIGS. 2 and 3, the supply auger 22 and the admix auger 23 extend along the longitudinal direction D I of the developing device 20 (the direction orthogonal to the view of FIG. 2).

[0031] The image forming apparatus 1 includes a first airflow path 71 which extends from the storing region 20A of the developing device 20 to the cleaner 45. The first airflow path 71 connects the storing region 20 A to the cleaner 45. The first airflow path 71 supplies air from the storing region 20A to the cleaner 45 by the pressure difference between the storing region 20A and tire cleaner 45. The first airflow path 71 includes an inlet 71 b provided above the developing roller 21. The inlet 71b is located at an end portion 25 of the developing device 20 on the side opposite to the photoreceptor device 40 when viewed from the developing roller 21, The pressure difference between the storing region 20A and the cleaner 45 is generated in such a manner that the developing roller 21 holds the developer while the developing roller 21 rotates. [0032] When the developing roller 21 rotates, air is taken to the storing region 20 A by the developer carried on the surface of the developing roller 21 so that the air pressure of the storing region 20A increases. For example, since air is taken to the storing region 20A by the spikes of the developer carried on the surface of the developing roller 21 , the air pressure of the storin g region 20A increases. Since the air pressure of the storing region 20A increases, the air of the storing region 20A is supplied to the cleaner 45 through the first airflow path 71 .

[0033] FIG. 4 is a rear perspective view showing the image development device 80 including the developing device 20 and the photoreceptor device 40. As shown in FIGS, 3 and 4, the photoreceptor device 40 extends along the longitudinal direction DI of the developing device 20. The first airflow path 71 extending from the storing region 20A of the developing device 20 extends to the cleaner 45 to bypass, for example, the upper side of the photoreceptor device 40.

[0034] As an example, the first airflow path 71 is formed as a tube. However, the first airflow path 71 may vary in shape, size and material. Further, the first airflow path 71 may in some examples not bypass the upper side of the photoreceptor device 40 and extend to the cleaner 45 to bypass, for example, an end portion 40b of the photoreceptor device 40 in the longitudinal direction D1. Accordingly, the position of the first airflow path 71 may be varied depending on examples.

[0035] FIG. 5 is a diagram schematically showing the cleaner 45. As shown in FIGS. 4 and 5, the cleaner 45 includes a tubular toner conveying path 46, a conveying member 47 that conveys the toner inside the toner conveying path 46, and a blade 48 which is located above the toner conveying path 46 to scrape off the toner from the surface of the photoreceptor 41. For example, the toner which is scraped from the surface of the photoreceptor 41 by the blade 48 falls into the toner conveying path 46. The toner conveying path 46, the conveying member 47, and the blade 48 extend along the longitudinal direction DI.

[0036] Tire conveying member 47 is, for example, an auger which includes a bar-shaped shaft portion and a blade portion formed in a spiral shape along the shaft portion. The cleaner 45 further includes a drive member 49 that rotates the conveying member 47. The drive member 49 includes, for example, a motor and a gear which rotate the conveying member 47. The conveying member 47 may rotate to convey the toner inside the toner conveying path 46 along the conveying direction D2. The conveying direction D2 is, for example, a direction extending along the longitudinal direction D I of the developing device 20.

[0037] The toner conveying path 46 includes a first end portion 46b including one end of the conveying direction D2 and a second end portion 46c including the other end of the conveying direction D2. The conveying member 47 conveys the toner from the first end portion 46b toward the second end portion 46c. The first end portion 46b is offset from the blade 48 in the conveying direction D2. Namely, the first end portion 46b is located upstream an end portion 48b of the blade 48 in the conveying direction D2. An outlet 71c of the first airflow path 71 is located on the outside of the toner conveying path 46 in the conveying direction D2 in relation to the end portion 48b of the blade 48.

[0038] The image forming apparatus 1 includes a second airflow path 72 which connects the cleaner 45 to the conveying region 20B of the developing device 20. For example, the second airflow path 72 extends from the toner conveying path 46 of the cleaner 45 to the outside of the cleaner 45. Tire second airflow path 72 includes an inlet 72b provided at the second end portion 46c of the toner conveying path 46. For example, the inlet 72b may be located at the upper portion of the toner conveying path 46. The toner enters the inlet 72b of the second airflow path 72 together with air.

[0039] As an example, the developing device 20 includes a toner supply port 26 which supplies the toner to the conveying region 20B. The toner supply port 26 communicates with the conveying region 20B. The second airflow path 72 includes, for example, an outlet 72c provided at the toner supply port 26. The second airflow path 72 supplies the toner from the toner supply port 26 to the conveying region 20B together with the air supplied from the storing region 20A of the developing device 20 set to a high pressure to the cleaner 45 through the first airflow path 71. As an example, the internal pressure of the storing region 20A of the developing device 20 is 20.3 Pa and the internal pressure of the second airflow path 72 is 14.3 Pa. Due to the pressure difference, the air and the toner are supplied from the cleaner 45 to the conveying region 20B through the second airflow path 72.

[0040] As an example, the second airflow path 72 which extends from the toner conveying path 46 includes an outlet 72c provided at the conveying region 20B of the developing device 20 located diagonally below the toner conveying path 46. As an example, the second airflow path 72 is formed as a tube. However, the second airflow path 72 may be one other than the tube and the shape, material , and position of the second airflow path 72 are not particularly limited.

[0041] Next, the operation and effect obtained from the image forming apparatus 1 will be described. As described above, in the image forming apparatus 1, the developing device 20 includes the storing region 20A of storing the developer and the conveying region 20B of supplying the developer to the storing region 20A. The photoreceptor device 40 includes the photoreceptor 41 which forms the toner image from the toner in the developer and the cleaner 45 which removes an excess toner remaining on the surface of the photoreceptor 41.

[0042] Further, the image forming apparatus 1 includes the first airflow path 71 which connects the storing region 20A to the cleaner 45 and the second airflow path 72 which connects the cleaner 45 to the conveying region 20B. Thus, air is supplied from the storing region 20A of the developing device 20 to the cleaner 45 through the first airflow path 71, so as to more efficiently convey the toner inside the cleaner 45 and to suppress the toner from adhering to the inner surface or the like of the toner conveying path 46.

[0043] In addition, the toner is conveyed in a dispersed state in the cleaner 45 by the air from the first airflow path 71 , so as to suppress the generation of toner aggregates inside the cleaner 45. Thus, it is possible to reduce the occurrence of image quality deterioration on the sheet 5 caused by toner aggregates. Further, in the image forming apparatus 1 , air is supplied from the storing region 20A to the cleaner 45 using the pressure difference between the storing region 20 A and the cleaner 45, without any air conveying device such as a pump, so as to promote a reduction in size of the image forming apparatus 1.

[0044] The pressure difference is generated when the developing roller 21 holds the developer while the developing roller 21 rotates, so as to use an increase in pressure of the storing region 20A of the developing device 20 in accordance with the rotation of the developing roller 21 in order to convey the toner of the cleaner 45. The conveying of the toner collected in the cleaner 45 can be assisted by the air from the first airflow path 71, so as to convey the toner in the cleaner 45 in a more stable manner.

[0045] FIG, 6 is a graph showing a measurement result of a toner conveying property of the image forming apparatus 1 with the first airflow path 71 and the second airflow path 72 and a toner conveying property of an image forming apparatus without the first airflow path 71 or the second airflow path 72. The vertical axis of the graph of FIG. 6 indicates the toner discharge amount from the cleaner 45 for 5 minutes. As shown in FIG. 6, the toner discharge amount for 5 minutes was 1.09 g in the image forming apparatus of the image forming apparatus without the first and second airflow paths, and the toner discharge amount for 5 minutes was 1.75 g in the image forming apparatus 1. In this way, it was found that the image forming apparatus 1 can convey and discharge about 60% more of the toner than the image forming apparatus without the first and second airflow paths.

[0046] FIG. 7 is a graph showing a measurement result of the internal pressure in the developing device 20 of the image forming apparatus 1 and the internal pressure in the developing device of the image forming apparatus without the first and second airflow paths. As shown in FIG. 7, the internal pressure of the developing device was about 30 Pa in the image forming apparatus without the first and second airflow paths, and the internal pressure of the developing device 20 was about 21 Pa in the image forming apparatus 1. In this way, it was found that the image forming apparatus 1 can suppress an increase in pressure inside the developing device 20 by about 30%, [0047] FIG. 8 is a graph showing a relationship between the internal pressure of the developing device 20 adopting ADR (trickle discharge method) and the excess discharge ratio of the developer from the developing device 20. The horizontal axis of the graph of FIG. 8 indicates the internal pressure of the developing device 20 and the vertical axis of the graph of FIG. 8 indicates the excess discharge ratio. The measurement unit of the excess discharge ratio is g/kPV and indicates the excess amount of the developer discharged from the developing device when printing 1000 sheets. As shown in FIGS. 7 and 8, the image forming apparatus 1 can reduce the internal pressure of the developing device by about 30% compared to the image forming apparatus having no first and second airflow paths, so as to suppress the excess discharge of the developer in the ADR.

[0048] As described above, the developing device 20 includes the developing roller 21 which is located at the storing region 20 A and conveys the developer and the first airflow path 71 may include the inlet 71 b provided above the developing roller 21. In this case, the distance from the inlet 71b to the cleaner 45 is shortened, so as to more efficiently supply the air of the storing region 20 A to the cleaner 45. The inlet 71b of the first airflow path 71 may be located at the end portion 25 of the developing device 20 on the side opposite to the photoreceptor device 40 when viewed from the developing roller 21. In this case, the vacant space inside the developing device 20 can be more effectively used as the inlet 71b to the first airflow path 71 .

[0049] As described above, tire cleaner 45 may include the tubular toner conveying path 46 and the conveying member 47 that conveys the toner inside the toner conveying path 46. The conveying member 47 may convey the toner from the first end portion 46b of the toner conveying path 46 toward the second end portion 46c along the conveying direction D2 that extends along the axis of the toner conveying path 46, The first airflow path 71 may include the outlet 71c provided at the first end portion 46b of the toner conveying path 46. In this case, the outlet 71c is provided at the upstream end portion of the toner conveying path 46, to supply? the air from the first airflow path 71 to the toner conveying path 46, along substantially its entire length, from the first end portion 46b of the toner conveying path 46 to the second end portion 46c, so as to further increase the toner conveying property inside the toner conveying path 46. [0050] The cleaner 45 includes the blade 48 provided above the toner conveying path 46 to scrape the toner from the surface of the photoreceptor 41. The blade 48 may extend along the conveying direction D2. The outlet 71c of the first airflow path 71 may be located on the outside of the toner conveying path 46 in the conveying direction D2 in relation to the end portion 48b of the blade 48. In this case, air can be sent from the outlet 71 c of the first airflow path 71 to the entire region in which the toner enters the toner conveying path 46 from the blade 48, so as to further increase the toner conveying property in the cleaner 45.

[0051] The second airflow path 72 may include the inlet 72b provided at the second end portion 46c of the toner conveying path 46 to supply the toner conveyed in the toner conveying path 46 together with air to the conveying region 20B of the developing device 20. In this case, the toner conveyed in tire toner conveying path 46 is returned to the developing device 20, so as to more efficiently use the toner.

[0052] Next, an image forming apparatus according to a modified example will be described. FIG. 9 is a diagram schematically showing a cross-section of an image development device 80A including a developing device 20D and a photoreceptor device 40 of the image forming apparatus according to the modified example. Since a part of the configuration of the image forming apparatus according to the modified example overlaps with a part of the configuration of the image forming apparatus 1 , redundant description will be omitted as appropriate.

[0053] Tire developing device 20D includes a filter 27 which discharges the air of the conveying region 20B to the outside of the developing device 20D. The filter 27 is disposed at a position facing the admix auger 23. The air of the conveying region 20B is discharged to the outside of the developing device 20D through the filter 27. For example, the filter 27 is disposed on the side opposite to the outlet 72c of the second airflow path 72 when viewed from the admix auger 23. As described above, in the developing device 20D with the filter 27, the air can be discharged from the filter 27 to the outside of the developing device 20D and the pressure of the conveying region 20B can be brought close to the atmospheric pressure, so as to increase the air conveying efficiency in the first airflow path 71 and the second airflow path 72. [0054] As described above, the cleaner 45 of the image forming apparatus 1 includes the conveying member 47 that is an auger. However, as shown in FIG. 10, the cleaner 45 according to the modified example may include a conveying member 47A that is a coil spring. As an example, the conveying member 47A is formed in a spiral shape by winding a square lumber having a rectangular cross-sectional shape. In the conveying member 47 A serving as the coil spring, the inside of the conveying member 47A serves as an air passage. Thus, the conveying member 47 A serving as the coil spring is provided to further increase the air/toner conveying property in the cleaner 45.

[0055] FIG. 11 is a cross-sectional view schematically showing a toner conveying path 46A and a first airflow path 71 A according to the modified example. As shown in FIG. 11, the first airflow path 71 A includes the bent portion 73. For example, the first airflow path 71 A is bent in the conveying direction D2 from the width direction D3 of the toner conveying path 46A at the bent portion 73.

[0056] For example, the first airflow path 71 A includes a rectifying member 74 disposed at the bent portion 73. The rectifying member 74 is disposed on, for example, the inner wall surface of the bent portion 73 of the first airflow path 71 A. The first airflow path 71 A includes the rectifying member 74, to more smoothly direct the flow of air in the first airflow path 71 A even with the bent portion 73.

[0057] An outlet 71d of the first airflow path 71 A communicates with the inner space of the toner conveying path 46A. At the outlet 71d, the air A flows along the inclination direction D4 inclined with respect to the conveying direction D2. The angle □ of the inclination direction D4 with respect to the conveying direction D2 is greater than 0 and less than 90 □. Further, the angle □ may be of approximately 100 to 80 □ according to some examples, or of approximately 20 □ to 60 □ in other examples, and can be changed as suitable.

[0058] In this case, as an example, the outlet 71d is formed between a first wall portion 46f of the toner conveying path 46A extending along the conveying direction D2 and a second wall portion 71 f extending along the inclination direction D4. In this way, the air A can flow more smoothly inside the toner conveying path 46A when the air A flows along the inclination direction D4 in the outlet 7 Id, so as to further increase the toner conveying property of the cleaner 45.

[0059] FIG. 12 is a perspective view showing the image development device 80A according to the modified example. As shown in FIG. 12, the toner conveying path 46 includes a discharge port 46d which discharges the toner conveyed by the conveying member 47 and is provided at the second end portion 46c. The cleaner 45 includes a waste toner collection container 45b which collects the toner discharged from the discharge port 46d. The discharge port 46d is located at the lower portion of the toner conveying path 46. The waste toner collection container 45b is disposed below the discharge port 46d and collects the toner discharged from the discharge port 46d.

[0060] A light toner having a low specific gravity enters the inlet 72b of the second airflow path 72 together with air. A toner having not flowed to the inlet 72b is conveyed to the discharge port 46d and is discharged from the discharge port 46d to the waste toner collection container 45b. The discharge port 46d and the waste toner collection container 45b are located on the outside of the toner conveying path 46 in the conveying direction D2 in relation to the inlet 72b of the second airflow path 72. Thus, only the light toner having a low specific gravity can be allowed to flow from the inlet 72b into the second airflow path 72.

[0061] As described above, tire cleaner 45 may include the waste toner collection container 45b which collects the toner not having flowed into the inlet 72b of the second airflow path 72 andthe inlet 72b of the second airflow path 72 may be located at the upper portion ofthe toner conveying path 46. The developing device 20 may include the toner supply port 26 which supplies the toner to the conveying region 20B and the second airflow path 72 may include the outlet 72c provided at the toner supply port 26. In this case, only the toner having a low specific gravity can be allowed to flow into the second airflow path 72 and the carrier or the like having a high specific gravity can be discharged from the toner conveying path 46 to the waste toner collection container 45b, Then, the toner having a low specific gravity can be supplied to the conveying region 20B through the second airflow path 72 and the toner supply port 26. Thus, it is possible to effectively use the toner having a low specific gravity.

[0062] It should be understood that other examples can be modified in their arrangement and details. For example, the image forming apparatus may use a one-component developer or may form a black-and-white image.

[0063] It is to be understood that not all aspects, advantages and features described herein may necessarily be achieved by, or included in, any one particular example. Indeed, having described and illustrated various examples herein, it should be apparent that other examples may be modified in arrangement and detail is omitted.

Claims

CLAIMS WHAT IS CLAIMED IS:

1. An image development device for an image forming apparatus, comprising: a developing device having a storing region to store a developer and a conveying region to supply the developer to the storing region; a photoreceptor device including a photoreceptor to form a toner image from a toner in the developer, and a cleaner to remove an excess toner remaining on a surface of the photoreceptor; a first airflow path connecting the storing region to the cleaner; and a second airflow path connecting the cleaner to the conveying region.

2. The image development device according to claim 1 , wherein the developing device includes a developing roller located in the storing region to convey the developer, and wherein the first airflow path includes an inlet provided above the developing roller to supply air from the storing region to the cleaner due to a pressure difference between the storing region and the cleaner.

3. The image development device according to claim 2, wherein the inlet of the first airflow path is located opposite to the photoreceptor device relative to the developing roller.

4. The image development device according to claim 1 , wherein the first airflow path includes a bent portion and a rectifying member disposed at the bent portion.

5. The image development device according to claim 1, wherein the cleaner includes a waste toner collection container to collect a residual toner having not flowed into an inlet of the second airflow path.

6. The image development device according to claim 1 , wherein the developing device includes a toner supply port to supply the toner to the conveying region, and wherein the second airflow path includes an outlet formed in the toner supply port.

7. The image development device according to claim 1, wherein the developing device includes a filter to discharge air of the conveying re gion to the outside of the de veloping device .

8. An image development device for an image forming apparatus, comprising: a developing device to supply a developer; a photoreceptor including a photoreceptor to form a toner image from the developer, and a cleaner to collect excess toner from a surface of the photoreceptor, wherein the cleaner includes a tubular toner conveying path to convey the excess toner in a conveying direction of the toner conveying path from a first end portion toward a second end portion of the toner conveying path; a first airflow path to supply an air flow from the developing device to the first end portion of the toner conveying path; and a second airflow path to supply an air flow from the second end portion of the toner conveying path to the developing device.

9. The image development device according to claim 8, wherein the cleaner includes a coil spring extending in the toner conveying path to convey the excess toner.

10. The image development device according to claim 8, wherein the cleaner includes a blade provided above the toner conveying path to scrape the excess toner from the surface of the photoreceptor, wherein the blade extends along the conveying direction, and wherein an outlet of the first airflow path is offset from the blade in the conveying direction of the toner conveying path.

11. The image development device according to claim 8, wherein the outlet of the first airflow path is to direct the air flow in an inclination direction that is inclined with respect to the conveying direction, and wherein an angle of the inclination direction with respect to the conveying direction is greater than 0° and less than 90°.

12. The image development device according to claim 8, wherein the developing device includes a storing region to store the developer and a conveying region to supply the developer to the storing region, wherein the first airflow path includes an inlet located in the storing region and an outlet located at the first end portion of the toner conveying path of the cleaner, and wherein the second air flow path includes an inlet provided at the second end portion of the toner conveying path of the cleaner and an outlet located at the conveying region of the developing device to supply the excess toner conveyed along the toner conveying path of the cleaner together with air, to the conveying region of the developing device.

13. The image development device according to claim 8, wherein an inlet of the second airflow path is located at an upper portion of the toner conveying path of the cleaner.

14. An image forming apparatus, comprising: a developing device having a storing region to store a developer and a conveying region to supply the developer to the storing region; a photoreceptor device including a photoreceptor to form a toner image from a toner in the developer, and a cleaner to remove an excess toner remaining on a surface of the photoreceptor; a first airflow path connecting the storing region to the cleaner; and a second airflow path connecting the cleaner to the conveying region.

15. The image forming apparatus according to claim 14, wherein the developing device includes a developing roller located in the storing region to convey the developer to the photoreceptor, and wherein the first airflow path includes an inlet provided above the developing roller.