JP2019174584A - Developing device and image forming apparatus - Google Patents

Abstract

To prevent an increase in temperature of a developing device while preventing an increase in transport cost of the developing device.SOLUTION: A developing device 8 of the present invention comprises: a housing 21 that stores a developer; a developing member 23 that rotates around the axis of rotation and develops an electrostatic latent image by using the developer inside the housing 21; and a ventilation duct 26 that is arranged outside the housing 21 and extends along the direction of the axis of rotation of the developing member 23. The ventilation duct 26 is foldably provided.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a developing device and an image forming apparatus including the developing device.

  2. Description of the Related Art Conventionally, an electrophotographic image forming apparatus includes a developing device that develops an electrostatic latent image formed on the surface of an image carrier such as a photosensitive drum.

  In such an image forming apparatus, when the temperature of the developing device increases as the image forming operation is performed, the fluidity of the developer in the developing device may be reduced, leading to an image defect. In particular, in recent years, the speed of image forming apparatuses has been increasing, and the amount of heat generated by the developing apparatus has increased accordingly. Therefore, a configuration that efficiently cools the developing apparatus and suppresses the high temperature of the developing apparatus is provided. It has been demanded.

  For example, Patent Document 1 discloses a housing for storing a developer (see “Developing Container 30” in Patent Document 1) and a ventilation duct (see “Air Vent 50” in Patent Document 1) arranged outside the housing. ). In this prior art, the developer in the housing is cooled by the air flow passing through the ventilation duct.

JP 2012-194224 A

  In Patent Document 1, when the amount of heat generated by the developing device increases as the speed of the image forming apparatus increases, it is required to increase the size of the ventilation duct. However, when the ventilation duct is increased in size as described above, the packing material for packing the developing device is also increased in size, and the transportation cost of the developing device is increased.

  Accordingly, an object of the present invention is to suppress the increase in the temperature of the developing device while suppressing an increase in the transportation cost of the developing device.

  A developing device according to the present invention includes a housing that contains a developer, a developing member that rotates around a rotation shaft and develops an electrostatic latent image using the developer in the housing, and an exterior of the housing. And a ventilation duct extending along a rotation axis direction of the developing member, and the ventilation duct is provided so as to be foldable.

  The developing device may further include a sensor fixed to the lower surface of the housing, the ventilation duct may be provided below the housing, and may cover the sensor from below.

  The ventilation duct may be provided so as to be foldable in a direction orthogonal to the rotation axis direction of the developing member.

  An image forming apparatus according to the present invention includes the developing device and a device main body to which the developing device is mounted.

  The ventilation duct includes a guide plate movable with respect to the housing, and a pair of connection plates that connect the housing and the guide plate, and each connection plate is in a state in which the ventilation duct is opened. The device body is provided with a guide rail that can be engaged with the guide plate, and the connection plate is provided with the connection plate. When the developing device is mounted on the apparatus main body in the bent posture, the guide plate moves along the guide rail to the side away from the housing, and the connection plates are moved from the bent posture to the side. It may be switched to the extended posture.

  The developing device is attached to the apparatus main body along the rotation axis direction of the developing member, and the apparatus main body includes a fan that generates cooling air, and a connection duct that connects the fan and the ventilation duct. A movable duct portion that is movable in the direction of the rotation axis of the developing member at a connection portion with either the ventilation duct or the connection duct. May be provided.

  According to the present invention, it is possible to suppress an increase in the temperature of the developing device while suppressing an increase in the transportation cost of the developing device.

1 is a schematic diagram illustrating an image forming apparatus according to an embodiment of the present invention. 1 is a schematic cross-sectional view showing a developing device according to an embodiment of the present invention. FIG. 6 is a perspective view showing a state in which the ventilation duct is opened in the developing device according to the embodiment of the present invention. FIG. 5 is a perspective view showing a state where the ventilation duct is folded in the developing device according to the embodiment of the present disclosure. 1 is a cross-sectional view illustrating an apparatus main body and a developing device according to an embodiment of the present invention. It is sectional drawing which shows the apparatus main body which concerns on one Embodiment of this invention. FIG. 5 is a front view showing a state where the ventilation duct is folded in the developing device according to the embodiment of the present invention. In the developing device according to an embodiment of the present invention, FIG. In the developing device according to an embodiment of the present invention, it is a front view showing a state where the ventilation duct is opened. It is sectional drawing which shows the apparatus main body and developing device which concern on other different embodiment of this invention.

  Hereinafter, an image forming apparatus 1 according to an embodiment of the present disclosure will be described with reference to the drawings. Arrows Fr, Rr, L, R, U, and Lo appropriately attached to the drawings respectively indicate the front side, the rear side, the left side, the right side, the upper side, and the lower side of the image forming apparatus 1.

  First, the overall configuration of the image forming apparatus 1 will be described. The image forming apparatus 1 is, for example, a complex machine that is provided with a print function, a copy function, a fax function, and the like.

  Referring to FIG. 1, the image forming apparatus 1 includes a box-shaped apparatus main body 2. An image reading device 3 for reading a document image is provided at the upper end of the apparatus body 2.

  A paper discharge tray 4 is provided on the upper part of the apparatus main body 2. An intermediate transfer belt 5 and four image forming units 6 are accommodated in a substantially central portion of the apparatus main body 2. Each image forming unit 6 corresponds to each color of black, cyan, magenta, and yellow. Each image forming unit 6 includes a photosensitive drum 7 (an example of an image carrier) and a developing device 8. An exposure apparatus 10 is accommodated in the lower part of the apparatus body 2. A paper feed cassette 11 that stores paper S (an example of a recording medium) is stored at the lower end of the apparatus body 2.

  A conveyance path P for the sheet S is provided on the right side of the apparatus main body 2. A paper feed unit 12 is provided at the upstream end of the transport path P. A secondary transfer unit 13 is provided in the middle portion of the transport path P. A fixing device 14 is provided in the downstream portion of the transport path P.

  Four toner containers 15 are accommodated in the upper part of the apparatus main body 2 below the paper discharge tray 4. Each toner container 15 contains black, cyan, magenta, and yellow toner, respectively.

  Next, an example of the operation of the image forming apparatus 1 will be described.

  First, an electrostatic latent image is formed on the photosensitive drum 7 of each image forming unit 6 by light from the exposure apparatus 10 (see the dotted arrow in FIG. 1). The developing device 8 of each image forming unit 6 develops the electrostatic latent image. As a result, the toner image is carried on the photosensitive drum 7 of each image forming unit 6. This toner image is primarily transferred from the photosensitive drum 7 of each image forming unit 6 to the intermediate transfer belt 5. As a result, a full-color toner image is formed on the intermediate transfer belt 5.

  Further, the paper S taken out from the paper feed cassette 11 by the paper feed unit 12 is transported downstream in the transport path P and enters the secondary transfer unit 13. In the secondary transfer unit 13, the full-color toner image formed on the intermediate transfer belt 5 is secondarily transferred to the paper S. The sheet S on which the toner image is secondarily transferred is further conveyed downstream along the conveyance path P and enters the fixing device 14. In the fixing device 14, the toner image is fixed on the paper S. The paper S on which the toner image is fixed is discharged onto the paper discharge tray 4.

  Next, the developing device 8 will be further described. An arrow I appropriately attached to each drawing indicates the inner side in the left-right direction of the developing device 8 (side approaching the central portion in the left-right direction of the developing device 8). 8 shows the outer side in the left-right direction (side away from the central part of the developing device 8 in the left-right direction).

  Referring to FIG. 2, the developing device 8 includes a housing 21, a pair of left and right stirring screws 22 housed in the lower portion of the housing 21, and a developing roller 23 (developing member) housed in the upper portion of the housing 21. An example), a regulating blade 24 provided below the developing roller 23, and a sensor 25 and a ventilation duct 26 provided below the housing 21.

  The housing 21 of the developing device 8 contains a developer (not shown). This developer is, for example, a two-component developer composed of a nonmagnetic toner and a magnetic carrier. An opening 31 is provided in the upper right part of the housing 21.

  On the lower surface of the bottom wall 21a of the housing 21, a pair of left and right guide pieces 32 protrude downward. A guide groove 33 is provided on the outer surface of each guide piece 32 in the left-right direction. Between each guide piece 32, upper space S1 opened toward the downward direction is formed.

  Each stirring screw 22 of the developing device 8 is rotatably supported by the housing 21. Each stirring screw 22 includes a stirring shaft 35 extending along the front-rear direction and a helical stirring blade 36 provided on the outer periphery of the stirring shaft 35.

  The developing roller 23 of the developing device 8 has a cylindrical shape and extends in the front-rear direction. The outer peripheral surface of the developing roller 23 is exposed to the outside of the housing 21 through the opening 31 of the housing 21 and faces the outer peripheral surface of the photosensitive drum 7. The developing roller 23 is rotatably supported by the housing 21 and rotates around a rotation axis X extending in the front-rear direction (see the dotted arrow in FIG. 2). That is, in the present embodiment, the front-rear direction is the rotation axis direction of the developing roller 23. A plurality of magnetic poles 38 are accommodated in the developing roller 23.

  The regulating blade 24 of the developing device 8 is fixed to the right side portion of the housing 21. The front end portion of the regulating blade 24 faces the outer peripheral surface of the developing roller 23 with an interval.

  The sensor 25 of the developing device 8 is disposed outside the housing 21. The sensor 25 is fixed to the lower surface of the bottom wall 21 a of the housing 21. The sensor 25 is accommodated in the upper space S <b> 1 of the housing 21. The sensor 25 is constituted by, for example, a magnetic permeability sensor, and detects the toner concentration of the developer in the housing 21 based on the magnetic permeability of the developer in the housing 21.

  With reference to FIGS. 2 to 4, the ventilation duct 26 of the developing device 8 is disposed outside the housing 21. The ventilation duct 26 extends along the front-rear direction. The ventilation duct 26 covers the sensor 25 from the lower side. The ventilation duct 26 is always provided at a distance from the sensor 25.

  The ventilation duct 26 is provided so as to be foldable in the up-down direction (direction orthogonal to the front-rear direction). With reference to FIGS. 2 and 3, in a state where the ventilation duct 26 is opened, a lower space S <b> 2 is formed inside the ventilation duct 26. The lower space S2 is opened upward. The lower space S2 is located directly below the upper space S1 of the housing 21 and communicates with the upper space S1 of the housing 21. With reference to FIG. 4, in a state where the ventilation duct 26 is folded, the lower space S <b> 2 is not formed inside the ventilation duct 26.

  2 to 4, the ventilation duct 26 includes a guide plate 40 and a pair of left and right connection plates 41 provided above the guide plate 40.

  The guide plate 40 of the ventilation duct 26 has a flat plate shape and extends along the front-rear direction. The guide plate 40 is provided in a horizontal posture. The guide plate 40 is provided so as to be movable in the vertical direction with respect to the housing 21.

  Each connection plate 41 of the ventilation duct 26 includes a first plate portion 43, a second plate portion 44 provided below the first plate portion 43, a width direction one end portion of the first plate portion 43, and a second plate portion 44. And a fulcrum portion 45 that rotatably connects one end portion in the width direction. The 1st board part 43 and the 2nd board part 44 have comprised flat form, and are extended along the front-back direction. The other end portion in the width direction of the first plate portion 43 is rotatably connected to each guide piece 32 of the housing 21, and the other end portion in the width direction of the second plate portion 44 rotates on the upper surface of the guide plate 40. Connected as possible. In this way, each connection plate 41 connects each guide piece 32 of the housing 21 and the guide plate 40.

  Each connection plate 41 of the ventilation duct 26 has an extended posture (see FIGS. 2 and 3) in which the ventilation duct 26 is opened and a bending posture (see FIG. 4) in which the ventilation duct 26 is folded. It is provided so that it can be switched. In a state where each connection plate 41 is in the extended posture, the first plate portion 43 and the second plate portion 44 are in a vertical posture, and the fulcrum portion 45 is below the first plate portion 43 and above the second plate portion 44. Is placed. In a state in which each connection plate 41 is in a bent posture, the first plate portion 43 and the second plate portion 44 are in a horizontal posture, and the fulcrum portion 45 is located on the inner side in the left-right direction of the first plate portion 43 and the second plate portion 44. Is placed.

  Next, the apparatus main body 2 will be further described.

  With reference to FIGS. 5 and 6, the apparatus main body 2 includes a mounting portion 51, and a fan 52 and a connection duct 53 provided behind the mounting portion 51.

  The mounting portion 51 of the apparatus main body 2 extends along the front-rear direction. The developing device 8 is detachably mounted on the mounting portion 51 along the front-rear direction. 5 and 6 indicates the mounting direction of the developing device 8 with respect to the mounting portion 51 (hereinafter simply referred to as “mounting direction”).

  Referring to FIG. 6, the mounting portion 51 is provided with a pair of left and right upper guide rails 55 (in FIG. 6, only the left upper guide rail 55 is shown). Each upper guide rail 55 extends horizontally along the front-rear direction. Each upper guide rail 55 is provided so as to be able to engage with a guide groove 33 provided in each guide piece 32 (see FIGS. 2 to 4) of the housing 21 of the developing device 8.

  Referring to FIG. 6, on both left and right sides of mounting portion 51, a pair of left and right lower guide rails 56 (in FIG. 6, only the left lower guide rail 56 is provided below right and left upper guide rails 55). Display). Each lower guide rail 56 includes an upstream horizontal portion 58, an inclined portion 59 provided on the rear side (downstream in the mounting direction) of the upstream horizontal portion 58, and a rear side (downstream in the mounting direction) of the inclined portion 59. And a downstream horizontal portion 60 provided. The upstream horizontal portion 58 and the downstream horizontal portion 60 extend horizontally along the front-rear direction. The inclined portion 59 is inclined downward from the front side (upstream side in the mounting direction) to the rear side (downstream side in the mounting direction). Each lower guide rail 56 is provided so as to be able to engage with a guide plate 40 (see FIGS. 2 to 4) of the ventilation duct 26 of the developing device 8.

  5 and 6, the fan 52 of the apparatus main body 2 is connected to a motor M (an example of a drive source). The fan 52 is rotated by the rotational driving force from the motor M and generates cooling air.

  The connection duct 53 of the apparatus main body 2 includes a fixed duct portion 61 connected to the fan 52 and a movable duct portion 62 provided so as to be movable along the front-rear direction with respect to the fixed duct portion 61. The movable duct portion 62 is biased toward the front side (upstream side in the mounting direction) by a coil spring 63 (an example of a biasing member).

  Next, the operation of developing the electrostatic latent image on the photosensitive drum 7 in the image forming apparatus 1 configured as described above will be described.

  Referring to FIG. 2, when developing the electrostatic latent image on the photosensitive drum 7, each stirring screw 22 and the developing roller 23 are rotated. Thus, when each stirring screw 22 rotates, the developer in the housing 21 is stirred by each stirring screw 22 and charged.

  The developer thus charged is pumped up by the magnetic force of the magnetic pole 38 accommodated in the developing roller 23 and is carried on the developing roller 23. Thus, the developer carried on the developing roller 23 is transported as the developing roller 23 rotates, and the thickness thereof is regulated by the tip of the regulating blade 24. The developer whose thickness is regulated in this way is further transported as the developing roller 23 rotates, and is introduced into a facing region between the outer peripheral surface of the developing roller 23 and the outer peripheral surface of the photosensitive drum 7. Along with this, the toner in the developer adheres to the electrostatic latent image on the photosensitive drum 7, and the electrostatic latent image on the photosensitive drum 7 is developed. As described above, the developing roller 23 develops the electrostatic latent image using the developer in the housing 21.

  Next, an operation for cooling the developing device 8 in the image forming apparatus 1 configured as described above will be described.

  Referring to FIG. 5, when cooling the developing device 8, the fan 52 is rotated by the rotational driving force from the motor M. When the fan 52 rotates in this way, the fan 52 generates cooling air (see the white arrow in FIG. 5).

  Thus, when the fan 52 generates cooling air, the cooling air is introduced into the upper space S1 of the housing 21 and the lower space S2 of the ventilation duct 26 via the connection duct 53. The cooling air thus introduced into the spaces S1 and S2 flows in the spaces S1 and S2 from the rear side to the front side, and is discharged from the front end portions of the spaces S1 and S2. When the cooling air passes through the spaces S1 and S2, the developing device 8 is cooled by the cooling air.

  As described above, in the present embodiment, the ventilation duct 26 is provided so as to be foldable. By adopting such a configuration, it is possible to increase the size of the ventilation duct 26 while suppressing an increase in the size of the packing material for packing the developing device 8. For this reason, it is possible to suppress an increase in the temperature of the developing device 8 while suppressing an increase in the transportation cost of the developing device 8.

  The ventilation duct 26 is provided below the casing 21 and covers the sensor 25 from below. By adopting such a configuration, the sensor 25 can be protected by the ventilation duct 26, and damage to the sensor 25 can be suppressed.

  The ventilation duct 26 is provided so as to be foldable in the vertical direction (a direction perpendicular to the rotation axis direction of the developing roller 23). By adopting such a configuration, the ventilation duct 26 can be easily folded.

  Further, the image forming apparatus 1 includes a developing device 8 and a mounting portion 51 to which the developing device 8 is mounted. By adopting such a configuration, it is possible to provide the image forming apparatus 1 including the developing device 8 that can simultaneously suppress an increase in transportation cost and a high temperature.

  Next, the operation of mounting the developing device 8 on the mounting portion 51 in the image forming apparatus 1 configured as described above will be described.

  As shown in FIG. 4, in a state before the developing device 8 is mounted on the mounting portion 51, each connection plate 41 of the ventilation duct 26 is in a bending posture, and the ventilation duct 26 is in a folded state. Yes.

  On the other hand, when the developing device 8 is mounted on the mounting portion 51, the operator inserts the developing device 8 into the mounting portion 51 from the front side toward the rear side. Accordingly, as shown in FIG. 7A, the guide grooves 33 of the guide pieces 32 of the housing 21 and the upper guide rails 55 engage with each other, and the guide plate 40 of the ventilation duct 26 and the lower guide rails. The lower surfaces of the 56 upstream horizontal portions 58 are engaged. In this state, each connection plate 41 of the ventilation duct 26 is still in a bent posture, and the ventilation duct 26 is in a folded state.

  From this state, when the operator further inserts the developing device 8 into the mounting portion 51 from the front side to the rear side, as shown in FIG. 7B, the guide groove of each guide piece 32 of the housing 21. 33 and the upper guide rails 55 are engaged with each other, the guide plate 40 of the ventilation duct 26 and the lower surface of the inclined portion 59 of each lower guide rail 56 are engaged. Therefore, the guide plate 40 of the ventilation duct 26 moves downward (side away from the casing 21) along the inclined portion 59 of each lower guide rail 56. In connection with this, each connection plate 41 of the ventilation duct 26 is gradually extended, and the ventilation duct 26 is gradually opened.

  From this state, when the operator further inserts the developing device 8 into the mounting portion 51 from the front side toward the rear side, the developing device 8 is mounted on the mounting portion 51. Accordingly, as shown in FIG. 7C, the guide plate 40 of the ventilation duct 26 and the lower guide rails of the ventilation duct 26 remain engaged with the guide grooves 33 of the guide pieces 32 of the housing 21 and the upper guide rails 55. The lower surface of the downstream horizontal part 60 of 56 engages. Thereby, each connection plate 41 of the ventilation duct 26 takes an extended posture, and the ventilation duct 26 is opened.

  When the developing device 8 is mounted on the mounting portion 51 as described above, the rear end portion of the ventilation duct 26 comes into contact with the front end portion of the movable duct portion 62 of the connection duct 53 as shown in FIG. Thereby, the movable duct 62 of the ventilation duct 26 and the connection duct 53 is connected, and the fan 52 and the ventilation duct 26 are connected via the connection duct 53.

  As described above, when the rear end portion of the ventilation duct 26 comes into contact with the front end portion of the movable duct portion 62 of the connection duct 53, the rear end portion of the ventilation duct 26 connects the front end portion of the movable duct portion 62 of the connection duct 53. Press toward the rear side (downstream side in the mounting direction). Accordingly, the movable duct portion 62 of the connection duct 53 moves rearward (downstream in the mounting direction) against the biasing force of the coil spring 63.

  As described above, in the present embodiment, when the developing device 8 is mounted on the mounting portion 51 in a state where each connection plate 41 of the ventilation duct 26 is in a bent posture, the guide plate 40 of the ventilation duct 26 is moved to each lower guide. The rail 56 moves downward (side away from the casing 21) along the inclined portion 59, and the connection plates 41 of the ventilation duct 26 are switched from the bent posture to the extended posture. By adopting such a configuration, the ventilation duct 26 is automatically opened in conjunction with the operation of mounting the developing device 8 on the mounting portion 51, thereby reducing the burden on the worker for mounting the developing device 8. It becomes possible to do.

  In addition, a movable duct portion 62 that is movable along the front-rear direction (the rotation axis direction of the developing roller 23) is provided at a connection portion of the connection duct 53 with the ventilation duct 26. By adopting such a configuration, it becomes possible to ensure the airtightness between the connection duct 53 and the ventilation duct 26, and to prevent the cooling air from leaking between the connection duct 53 and the ventilation duct 26. it can.

  In the present embodiment, a movable duct portion 62 that is movable along the front-rear direction (the rotation axis direction of the developing roller 23) is provided at a connection portion of the connection duct 53 with the ventilation duct 26. On the other hand, in another different embodiment, as shown in FIG. 8, a movable duct movable along the front-rear direction (rotational axis direction of the developing roller 23) at the connection portion of the ventilation duct 26 with the connection duct 53. The part 62 may be provided.

  In the present embodiment, the ventilation duct 26 is automatically opened in conjunction with the operation of mounting the developing device 8 on the mounting portion 51. On the other hand, in another different embodiment, the operator may manually open the ventilation duct 26, or the ventilation duct 26 may be opened by its own weight as the packaging of the developing device 8 is opened.

  In the present embodiment, the image forming apparatus 1 is a multifunction machine. On the other hand, in other different embodiments, the image forming apparatus 1 may be a printer, a copier, a facsimile, or the like.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Apparatus main body 8 Developing apparatus 21 Case 23 Developing roller (an example of developing member)
25 Sensor 26 Ventilation duct 40 Guide plate 41 Connection plate 52 Fan 53 Connection duct 56 Lower guide rail 62 Movable duct part X Rotating shaft

Claims (6)

A housing for containing the developer;
A developing member that rotates around a rotation axis and develops the electrostatic latent image using the developer in the housing;
A ventilation duct disposed outside the housing and extending along a rotation axis direction of the developing member, and
The developing device, wherein the ventilation duct is foldable. Further comprising a sensor fixed to the lower surface of the housing,
The developing device according to claim 1, wherein the ventilation duct is provided below the housing and covers the sensor from below.   The developing device according to claim 1, wherein the ventilation duct is provided so as to be foldable in a direction orthogonal to the rotation axis direction of the developing member. The developing device according to any one of claims 1 to 3,
An image forming apparatus comprising: an apparatus main body to which the developing device is mounted. The ventilation duct is
A guide plate movable relative to the housing;
A pair of connection plates for connecting the housing and the guide plate;
Each of the connection plates is
An extended posture for opening the ventilation duct;
It is provided so that it can be switched between a bending posture in which the ventilation duct is folded,
The apparatus main body includes a guide rail that can be engaged with the guide plate,
When the developing device is mounted on the apparatus main body in a state where the connection plates are in the bent posture, the guide plate moves along the guide rail to the side away from the housing, and the connection plates The image forming apparatus according to claim 4, wherein the image forming apparatus switches from the bent posture to the extended posture. The developing device is attached to the apparatus main body along the rotation axis direction of the developing member,
The apparatus main body is
A fan that generates cooling air;
A connection duct connecting the fan and the ventilation duct,
Either the ventilation duct or the connection duct is provided with a movable duct portion that is movable along the rotational axis direction of the developing member at a connection portion with the other of the ventilation duct or the connection duct. The image forming apparatus according to claim 4, wherein the image forming apparatus is provided.

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