JP2009008964A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device, capable of suppressing an excessive rise of temperature of a developer due to friction of the developer or a developing roller with a regulating member to thereby ensure satisfactory developing performance while suppressing the degradation of the developer, and attaining the suppression of the rise of temperature of the developer with a simple structure and a reduced number of part items by eliminating a complicated operation for incorporation to a rotary developing device. <P>SOLUTION: The image forming device comprises a support member 66 formed of a material having high heat conductivity, the member including an attachment part 66a for fixing a regulating member 55 and a contact part 66 exposed to the outer circumference of a developing device 16, and a flexible brush 72 with high heat conductivity, which can contact the contact part 66b of the support member 66. When the developing device 16 is rotated from a developing position and located in the following stop position, the contact part 66b contacts the brush 72. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a complex machine using an electrophotographic process, and more particularly to an image forming apparatus provided with a so-called rotary type developing device.

  In general, in a color image forming apparatus, a developing roller for each color is supported on a cylindrical rotary rack that is configured so that the developing device for each color can be rotated by using a one-component developer. In some cases, a so-called rotary type developing device that performs development while sequentially facing an image carrier is used. Each color developer includes a stirring member that stirs and mixes the developer to charge the developer, a supply roller that supplies the developer from the stirring member to the developing roller, a developing roller that carries the developer, and a developing roller. And a regulating member for regulating the layer thickness of the developer. In such a developing device, when the developing roller rotates while contacting the regulating member in order to regulate the developer layer thickness, friction occurs between the regulating member and the developing roller, and frictional heat is generated. When the temperature of the developer is increased by this heat generation, the fluidity of the developer is deteriorated. When the developer fluidity deteriorates, the developer performance deteriorates, or the melted toner adheres to the regulating member or developer carrier, resulting in development unevenness such as background stains and streaks. There is a problem that performance decreases.

  Therefore, in Patent Document 1, in an image forming apparatus equipped with a rotary type developing device, a plurality of developing units containing toners of different colors are provided in a rotary rack, and the developing units of the respective colors are sequentially opposed to the photosensitive drum. Rotate the rotary rack. At a position facing the photosensitive drum, toner is supplied from the developing roller of the developing device to the photosensitive drum, and the toner is carried on the latent image formed on the photosensitive drum, and the toner is transferred from the photosensitive drum via the transfer belt. Is transferred and fixed on the paper. An air circulation part is formed in the housing of each color developing device, and this air circulation part has a micro hole through which air can flow but toner cannot pass through a communication hole formed in the outer peripheral surface of the housing. It is configured with a sticker.

  Accordingly, even when a heat generation source is present near the toner accommodated in the housing, air is discharged from the air circulation portion to the outside.

  In Patent Document 2, a developing roller that carries and conveys a developer, a regulating member that is provided so as to be in contact with the developing roller and regulates the layer thickness of the developer carried on the developing roller, and the regulation A heat sink for dissipating the developer at a position in the vicinity of the member, and for dissipating the developer, the heat sink facing the developing roller and absorbing heat from the developer, and A technology of a developing device having a heat radiating portion for radiating heat of a facing portion is disclosed.

  As a result, the developer is sufficiently charged by friction with the regulating member, the heat generated by the friction is directly absorbed by the facing portion, and the absorbed heat is radiated outside the developing device by the heat radiating portion. Further, the temperature of the developer is prevented from excessively increasing.

  However, in Patent Document 1 described above, an air circulation part is formed in a plurality of developing units containing toners of different colors, the developing device is enlarged, and a seal is attached to each color developing unit. There is a disadvantage that the number of parts increases and it takes time to assemble. Further, if heat from another heat source such as a fixing device stays in the image forming apparatus, this heat may flow through the developing unit via the air circulation unit and the developer may be heated.

Further, in Patent Document 2, a heat sink is provided in a plurality of developing devices containing toners of different colors, the developing device is enlarged, and a heat sink is attached to the plurality of developing devices, so that the number of parts increases. There was an inconvenience that it took time to assemble.
Japanese Patent Laying-Open No. 2004-287055 (paragraphs [0038] and [0039], FIG. 13) JP 2006-139045 A (paragraphs [0061], [0062], FIG. 4)

  The present invention has been made to solve the above-described problems, and suppresses excessive temperature rise of the developer due to friction between the developer or the developing roller and the regulating member, and improves the flowability of the developer. An image that reduces the number of parts by reducing the number of parts with a simple configuration and eliminating the troublesome work of assembling it into a rotary developing device to suppress deterioration and obtain good development performance and to suppress the temperature rise of the developer. An object is to provide a forming apparatus.

  To achieve the above object, the present invention relates to a rotary rack provided with a plurality of developing devices at different positions in the circumferential direction, and development for developing an electrostatic latent image formed on an image carrier carrying a developer. An image provided with a roller, a regulating member that abuts against the developing roller and regulates the layer thickness of the developer, and a driving member that rotates the rotary rack to a developing position where the developing roller sequentially faces the image carrier. In the forming apparatus, a support member made of a heat conductive material in which an attachment portion for fixing the regulating member and a contact portion exposed on the outer periphery of the developing device is formed, and a cooling member that can contact the contact portion; And the contact portion is in contact with the cooling member at a predetermined position of the developing device.

  According to this configuration, although frictional heat is accumulated in the regulating member due to friction generated when the developing roller rotates while contacting the regulating member, the supporting member is provided with the regulating member fixed at a predetermined position of the developing device. When contacting the cooling member having a high thermal conductivity, the heat of the regulating member moves to the cooling member.

  According to this configuration, when the rotary rack rotates, each support member of the plurality of developing devices sequentially contacts the cooling member provided outside the developing device.

  According to the present invention, in the image forming apparatus configured as described above, the cooling member is formed of a brush having flexibility and made of a heat conductive material. According to this configuration, when the rotary rack rotates and the developing device comes to a predetermined position, the support member of the developing device comes into contact with the brush.

  Further, according to the present invention, in the image forming apparatus having the above configuration, a blower mechanism having a fan and a duct tube, one end portion for fixing the cooling member, and the other end portion facing the duct tube are formed. And a heat radiating plate extending in the longitudinal direction of the developing unit, and the air blowing mechanism circulates air in the vicinity of the heat radiating plate. According to this configuration, the frictional heat accumulated in the regulating member moves to the heat radiating plate via the support member and the cooling member. The hot air radiated from the heat sink flows through the duct pipe and is blown by the fan.

  In the image forming apparatus having the above-described configuration, the predetermined position is a position where the rotary rack is stopped. According to this configuration, the support member contacts the cooling member when the developing device is at the stop position.

  According to the present invention, in the image forming apparatus having the above-described configuration, the developing unit includes a storage unit that stores the developer, and the developer flows in the storage unit by rotation of the rotary rack, and the predetermined position is The developer is at a position farthest from the regulating member. According to this configuration, the support member comes into contact with the cooling member when the developer flowing in the accommodating portion is at a position farthest from the regulating member.

  In the image forming apparatus having the above-described configuration, the predetermined position is a stop position next to the development position. According to this configuration, when the developing device is rotated from the developing position and is in the next stop position, the support member contacts the cooling member.

  According to the first aspect of the present invention, when the support member fixed with the regulating member comes into contact with the cooling member having a high thermal conductivity at a predetermined position of the developing device, it accumulates in the regulating member due to friction with the developing roller. Since the frictional heat moves to the cooling member, it is possible to suppress the temperature of the developer from being excessively increased, to suppress the deterioration of the fluidity of the developer, and to obtain good development performance.

  According to the first aspect of the present invention, when the rotary rack rotates, each support member of the plurality of developing devices sequentially contacts the cooling member provided outside the developing device, so that the plurality of developing devices are cooled. There is no need to provide a member, the apparatus has a simple configuration, the troublesome work for assembling the developing device can be omitted, and the number of parts can be reduced.

  According to the second aspect of the present invention, when the rotary rack rotates and the developing device comes to a predetermined position, the support member of the developing device comes into contact with the flexible brush. There is no possibility that the rotational torque will increase, and even if the brush contacts the developing roller during the rotation of the rotary rack, there is no possibility that the surface of the developing roller will be damaged.

  According to the invention described in claim 3, the heat accumulated in the regulating member moves to the heat radiating plate via the support member and the cooling member. The hot air radiated from the heat radiating plate circulates in the duct pipe and is blown by the fan, so that the temperature of the developer is prevented from excessively rising and there is no possibility that the hot air stays in the image forming apparatus.

  According to the fourth aspect of the present invention, since the support member contacts the cooling member when the developing device is at the stop position, the regulating member is caused by friction with the developing roller over a long period during the stop. Since the frictional heat accumulated in the movement to the cooling member via the support member, the heat accumulated in the regulating member can be surely removed.

  According to the fifth aspect of the present invention, the support member contacts the cooling member when the developer flowing in the accommodating portion is at a position farthest from the regulating member. In this state, the frictional heat accumulated in the regulating member due to friction with the developing roller does not move to the developer accommodated in the accommodating portion, and moves to the cooling member via the support member. Accordingly, it is possible to suppress the temperature of the toner from being excessively increased and suppress the deterioration of the fluidity of the toner, thereby obtaining good development performance.

  According to the sixth aspect of the invention, when the developing device is rotated from the developing position and is in the next stop position, the support member contacts the cooling member. Immediately after development in which frictional heat is accumulated in the regulating member due to friction, that is, in a state where the amount of heat due to friction of the regulating member is large, the heat of the regulating member moves to the brush via the support member. The heat generated can be surely removed.

  Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments. The embodiment of the present invention shows the most preferable form of the invention, and the use of the invention and the terms shown here are not limited thereto.

  FIG. 1 is a schematic cross-sectional view for explaining a schematic configuration of an image forming apparatus according to an embodiment of the present invention.

  The image forming apparatus 1 includes an image forming unit 10, a toner replenishing device 20, an intermediate transfer unit 24, a paper feeding unit 30, a paper transport unit 35, a secondary transfer unit 45, a fixing device 47, and the like.

  As shown in FIG. 1, the image forming unit 10 includes a rotary developing unit 2, a photosensitive drum 11, a charging roller 12, a drum cleaning device 13, a laser unit 14, and the like.

  The photosensitive drum 11 is an image bearing member on which an electrostatic latent image is formed, and is driven to rotate about the center of the image forming apparatus 1 (the direction of rotation is indicated by an arrow). The rotation shaft (not shown) is provided so as to extend perpendicular to the paper surface of FIG. The photosensitive drum 11 is formed so as to have a photosensitive layer such as amorphous silicon or an OPC photosensitive member.

  The charging roller 12 is provided on the photosensitive drum 11. The charging roller 12 is in contact with the photosensitive drum 11 and is rotatably supported in order to uniformly charge the surface of the photosensitive drum 11. A cleaner 12 a that cleans deposits adhering to the charging roller 12 is provided above the charging roller 12.

  The drum cleaning device 13 is provided on the right side of the photosensitive drum 11 in FIG. 1, and is for cleaning toner (developer) and deposits remaining on the surface of the photosensitive drum 11.

  The rotary developing unit 2 is for developing the electrostatic latent image formed on the photosensitive drum 11 with toner of each color, and is provided adjacent to the left side of the photosensitive drum 11 in FIG. The rotary developing unit 2 includes a rotary rack 15 and four developing devices 16B (black), 16Y (yellow), 16C (cyan), and 16M (magenta) supported by the rotary rack 15. It is a cylindrical shape that can rotate around the shaft 15a. The rotating shaft 15 a passes through the center of the rotary rack 15, and the axial direction thereof is parallel to the axial direction of the rotating shaft of the photosensitive drum 11.

  The rotary rack 15 has four sections that are divided into four equal parts in the circumferential direction by a partition frame 15b extending radially from the center of the rotating shaft 15a. In each section, developing devices 16B, 16Y, 16C, and 16M corresponding to four toner colors of black, yellow, cyan, and magenta are arranged, and the developing devices 16B, 16Y, 16C, and 16M have the same configuration. is there. When the rotary developing unit 2 rotates, the developing rollers 53 of the developing units 16B, 16Y, 16C, and 16M face the photosensitive drum 11 with a predetermined gap. The detailed configuration of the rotary rack 15 and the developing devices 16B, 16Y, 16C, and 16M will be described later.

  The laser unit 14 is for scanning and exposing the photosensitive drum 11 based on image information from an external computer or the like, and is provided above the rotary developing unit 2. Data for causing the laser unit 14 to output the laser light 14L is created by the data processing unit 17 that receives image information. Then, the laser light 14L is emitted from the laser unit 14. A reflection mirror 18 is provided on the optical path of the laser beam 14L, and the laser beam 14L is irradiated onto the surface of the photosensitive drum 11 by the reflection mirror 18 (the laser beam 14L is shown by a two-dot chain line). The laser unit 14 includes a laser light source, a polygon mirror, a polygon mirror driving motor, and the like (not shown).

  The toner supply device 20 includes a toner storage container 21 and a toner supply member 22. The toner storage containers 21 are provided above the photosensitive drum 11 and the intermediate transfer belt 25, and four toner storage containers 21 are arranged side by side in the direction perpendicular to the paper surface of FIG. Each toner storage container 21 is a portion that stores toner to be replenished to the developing devices 16B, 16Y, 16C, and 16M of the rotary developing unit 2. That is, each toner storage container 21 stores toner of any one color of black, yellow, cyan, and magenta. In FIG. 1, the toner container 21 is invisible except for one toner container 21.

  The toner replenishing member 22 is disposed above the photosensitive drum 11 in a space between the laser unit 14 and the toner container 21 and is configured to be movable up and down, and is provided in four corresponding to each color. Each toner supply member 22 is connected to the corresponding toner storage container 21 by a pipe, a hose, or the like, and supplies the toner of each color stored in the toner storage container 21 to the corresponding developing devices 16B, 16Y, 16C, and 16M.

  The intermediate transfer unit 24 includes an intermediate transfer belt 25 to which toner images of respective colors formed on the photosensitive drum 11 are sequentially transferred, a driving roller 26 for stretching and driving the intermediate transfer belt 25, and a tension roller 27. A primary transfer roller 28 that faces the photosensitive drum 11 with the intermediate transfer belt 25 therebetween, and a driven member provided near the primary transfer roller 28 and between the drive roller 26 and the primary transfer roller 28. The roller 28 a and a belt cleaning device 29 for cleaning the intermediate transfer belt 25 are configured. The intermediate transfer belt 25 stretched around each roller rotates and passes through the nip between the photosensitive drum 11 and the primary transfer roller 28, and the toner images of the respective colors are sequentially primary-transferred, and the primary-transferred toner. The image is transferred to the paper P by the secondary transfer unit 45.

  The paper feed unit 30 includes a paper feed cassette 31, a manual feed tray 32, and the like. A paper feed cassette 31 having a placement plate 31 a on which the paper P is placed is provided at the bottom of the image forming apparatus 1. In addition, the paper feed unit 30 prevents the double feed to the right side of the pickup roller 33 and the pickup roller 33 to the right of the pickup cassette 31 in order to send out the paper P on the loading plate 31 a one by one to the paper conveyance path. A roller pair 34 is provided. Further, a manual feed tray 32 is provided on the right side surface of the apparatus so that paper can be separately fed. The manual feed tray 32 is also provided with a pickup roller 33 for sending the paper P one by one to the paper transport path.

  The paper transport unit 35 is for transporting the paper P in the image forming apparatus 1. The sheet conveying section 35 is a sheet for discharging the image-formed sheet P from the sheet feeding section 30 to a secondary transfer roller 46 described later, and from the secondary transfer roller 46 through the fixing device 47. From the second conveyance path 37 that reaches the discharge port 42, the reverse conveyance path 38 that is provided so as to connect the middle of the first conveyance path 36 to the middle of the second conveyance path 37 on the downstream side of the fixing device 47 in the sheet conveyance direction. Composed. A discharge tray 43 for receiving the discharged paper P is provided at the end of the second transport path 37. Note that the paper transport direction is indicated by arrows.

  A curved portion 39 is provided in the first transport path 36 in order to reverse the transport direction of the paper P sent out from the paper feed cassette 31. In addition, at the upper part of the curved portion 39, the conveyance path from the manual feed tray 32 joins. In front of the secondary transfer roller 46, a registration roller pair 40 for controlling the conveyance timing of the paper P is disposed. A plurality of pairs of conveyance rollers 41 are provided in the conveyance path in which these elements are provided, and a guide plate (not shown) for guiding the paper P is also provided as appropriate.

  The secondary transfer unit 45 includes a secondary transfer roller 46 and a driving roller 26. The secondary transfer roller 46 is for transferring the toner image transferred to the intermediate transfer belt 25 onto the sheet P conveyed so as to be sandwiched between the secondary transfer roller 46 and the intermediate transfer belt 25. Therefore, the secondary transfer roller 46 is supported so as to be rotatable and in contact with and away from the intermediate transfer belt 25 so as to form a nip via the drive roller 26 and the intermediate transfer belt 25. Further, a voltage is applied to the secondary transfer roller 46 so that the toner is transferred onto the paper P at a predetermined timing by a voltage applying means (not shown).

  The fixing device 47 is for melting and fixing the toner transferred onto the paper P, and is provided in the middle of the second transport path 37 and below the rotary developing unit 2. The fixing device 47 includes a heating roller 48 that incorporates a heater and a pressure roller 49 that presses the heating roller 48. The toner is heated and pressurized and fixed on the paper P.

  Next, an image forming operation will be described. The image forming apparatus 1 executes an image forming operation based on the input image data as follows.

  First, the photosensitive drum 11 is charged by the charging roller 12. The laser unit 14 scans and exposes the surface of the photosensitive drum 11 in accordance with data from the data processing unit 17 to which image data is input, and the electrostatic latent image is formed on the photosensitive drum 11. Is formed. Next, the rotary developing unit 2 is rotated counterclockwise in FIG. 1, and any of the corresponding color developing devices 16 faces the photosensitive drum 11. In this state, the electrostatic latent image on the photosensitive drum 11 is developed by supplying the corresponding color toner. The developed toner image is transferred to the intermediate transfer belt 25. The toner remaining on the photosensitive drum 11 after the transfer is cleaned by the drum cleaning device 13. The above operation is sequentially repeated for each color, and a full-color toner image is formed on the intermediate transfer belt 25.

  On the other hand, in the paper feed unit 30, one sheet P is taken out from the paper feed cassette 31 or the manual feed tray 32 by the pickup roller 33 and conveyed to the registration roller pair 40. Thereafter, the sheet P is conveyed from the registration roller pair 40 to the toner image on the intermediate transfer belt 25 in time, and is guided to the secondary transfer unit 45. A predetermined voltage is applied to the secondary transfer roller 46 while being in contact with the intermediate transfer belt 25, and the toner image on the intermediate transfer belt 25 is transferred to the paper P. The sheet P is guided to the fixing device 47 through the second conveyance path 37, and the toner image is fixed on the sheet P by the fixing device 47. The fixed sheet P is discharged from the sheet discharge port 42 to the discharge tray 43 through the branching claw 44.

(First embodiment)
Next, the developing devices 16B, 16Y, 16C, and 16M supported by the rotary developing unit 2 will be described with reference to FIG. Here, since the configurations of the developing devices 16B, 16Y, 16C, and 16M are the same, the following description and the reference numerals of the drawings are omitted unless otherwise indicated. The description will be made in a unified manner with the vessel 16. Accordingly, the following description applies in common to the developing devices 16B, 16Y, 16C, and 16M unless otherwise specified.

  FIG. 2 is a cross-sectional view showing a schematic configuration of the developing device 16 according to the first embodiment of the present invention. 2 shows a state where the developing roller 53 is in a developing position facing the photosensitive drum 11.

  The developing device 16 includes a frame 51, a partition member 52, a developing roller 53, a supply roller 54, a regulating member 55, a stirring member 56, a support member 66, and the like.

  The frame 51 constitutes the outer shell of the developing device 16 with the lower inner wall portion 51a shown in FIG. 2, which is the bottom of the developing device 16, the upper inner wall portion 51b shown in FIG. Each member is provided inside and contains toner.

  The partition member 52 is formed of, for example, a metal or resin plate member, separates the toner supply unit 58 and the toner storage unit 59, and includes a first partition member 61 and a second partition member 62. The first partition member 61 is provided in the frame 51 of the developing device 16 from the inner wall portion 51a adjacent to the developing roller 53 and the supply roller 54 toward the opposed inner wall portion 51b (from the bottom to the top in FIG. 2). . On the other hand, the second partition member 62 is directed from the inner wall portion 51b toward the first partition 61 so as to face the first partition member 61 on the toner supply portion 58 side relative to the first partition member 61 (from the top in FIG. 2). In the downward direction). The partition member 52 is separated into the toner supply unit 58 and the toner storage unit 59. The toner supply unit 58 is a part that supplies toner to the photosensitive drum 11, and includes a developing roller 53, a supply roller 54, a regulating member 55, and the like, and a stirring member 56 is arranged in the toner storage unit 59. Opposing portions of the first partition member 61 and the second partition member 62 are passage portions 64 for the toner to move from the toner storage portion 59 to the toner supply portion 58.

  A part of the developing roller 53 is exposed from the frame 51, and is opposed to the photosensitive drum 11 (partially shown by a broken line in FIG. 2) and can rotate about the axis 53 b. Supported by Then, the rotary developing unit 2 rotates, and the developing roller 53 on which a thin layer of toner of each color is formed is opposed to the photosensitive drum 11 and supplies toner to the photosensitive drum 11. A seal member 53a is provided between the developing roller 53 and the frame 51 to prevent toner leakage.

  The supply roller 54 is provided between the developing roller 53 and the partition member 52 so as to be in contact with the developing roller 53 in order to supply and convey toner to the developing roller 53. The supply roller 54 is rotatable and supported so that the axis 54b of the supply roller 54 and the axis 53b of the developing roller 53 are parallel to each other. The supply roller 54 is rotated in the same direction as the developing roller 53 (clockwise in FIG. 2) by a drive mechanism (not shown) including a gear, a motor, and the like. The supply roller 54 supplies toner to the developing roller 53 at the contact portion between the developing roller 53 and the supply roller 54 in the upper contact portion (near the regulating member 55) in FIG. The portion (near the inner wall portion 51a) functions to scrape off the toner that has not been used for development.

  The regulating member 55 is for contacting the developing roller 53 and rotating the developing roller 53 to form a thin layer of toner on the developing roller 53, and further has a function of charging the toner by friction. The regulating member 55 is formed in a film shape or a blade shape extending in the direction of the axis 53 b, one end abuts against the developing roller 53, and the other end is fixedly held by the support member 66. The regulating member 55 is made of a metal having a high thermal conductivity such as copper, aluminum, and stainless steel, and moves frictional heat generated at one end to the other end having a low temperature due to friction with the developing roller 53.

  The support member 66 is fixedly held on the inner wall portion 51b, and an attachment portion 66a and a contact portion 66b are formed. The restricting member 55 is fixed and held on the attachment portion 66a by a screw or the like. The contact portion 66b is exposed to the outer periphery of the developing device 16 so that a brush described later outside the developing device 16 can be contacted, and rotates so as not to contact the photosensitive drum 11 when the rotary developing unit 2 rotates. The distance from the center of the shaft 15a is equal to or less than the outer diameter of the developing device 16. The support member 66 extends in the direction of the axis 53b and is formed of a metal having a high thermal conductivity such as copper, aluminum, stainless steel or the like. As a result, the frictional heat accumulated in the regulating member 55 is absorbed by the mounting portion 66a and further moved to the contact portion 66b having a low temperature.

  The agitating member 56 is for agitating the toner in the toner accommodating portion 59, and is provided with an axis parallel to and parallel to the supply roller 54 and the developing roller 53, and includes an axial portion 56a, an agitating blade 56b, and the like. The The shaft portion 56a is provided so as to be bridged in the toner storage portion 59 and is rotatably supported. As shown in FIG. 2, the shaft portion 56a has a T-shaped cross section, and its axial end is connected to a gear and a motor (not shown) and rotated. For example, a film-like or sheet-like stirring blade 56b made of a resin such as PET is attached to the shaft member 56a, and the stirring member 56 is configured.

  FIG. 3 is a side sectional view showing the configuration of the developing device 16 and the cooling device 71 provided in the rotary rack 15 according to the first embodiment of the present invention. FIG. 4 is a plan view showing the configuration of the developing device 16 and the cooling device 71 provided in the rotary rack 15. 3 and 4 show the state of the retracted position where the developing device 16B has completed the development.

  As shown in FIG. 3, the cooling device 71 includes a brush 72 as a cooling member, a heat radiating plate 73, a duct pipe 74, a fan 75, and the like. One cooling device 71 is disposed above the rotary rack 15 (upper side in FIG. 3).

  The brush 72 is provided by bundling a large number of flexible wires having high thermal conductivity such as carbon fiber and extending in the axial direction of the rotary shaft 15a. One end portion 72 a of the brush 72 can be in contact with the contact portion 66 b of the support member 66, and the other end portion 72 b is attached to the heat radiating plate 73 and held. Therefore, when the brush 72 comes into contact with the support member 66, the heat accumulated in the support member 66 is absorbed by the one end portion 72a in contact with the contact portion 66b, and further moved to the other end portion 72b having a low temperature. .

  As shown in FIG. 4, the heat radiating plate 73 is formed of a rectangular plate extending in the longitudinal direction of the developing device 16, and is fixed to the apparatus main body 1a. The other end 72b of the brush 72 is attached to one surface 73a of the heat radiating plate 73, and the end surface 73b is disposed so as to face the duct tube 74 on the apparatus main body 1a side. Further, since the heat radiating plate 73 is formed of a metal having high thermal conductivity such as copper, aluminum, and stainless steel, the heat accumulated in the brush 72 is transferred to the heat radiating plate 73 via the other end portion 72b of the brush 72. Moved.

  The duct pipe 74 and the fan 75 are connected to form a blowing mechanism, and this blowing mechanism is fixed to the apparatus main body 1. Air taken in from the opening 74 a is blown into the duct pipe 74 and exhausted from the fan 75 to the outside of the image forming apparatus 1.

  Next, the rotational drive configuration of the rotary developing unit 2 will be described. As shown in FIG. 4, the rotary rack 15 holding the developing devices 16B, 16Y, 16C, and 16M (16C and 16M are invisible in FIG. 4) is rotatably supported on the apparatus main body 1a by the rotation shaft 15a. A gear 81 coaxial with the rotation shaft 15a is provided. A motor 83 is fixed to the apparatus main body 1 a, and a motor gear 82 meshes with the gear 81. When the motor 83 is rotated, the rotary rack 15 is rotated via the motor gear 82 and the gear 81, and the development is completed at the positions where the developing units 16B, 16Y, 16C, and 16M are opposed to the photosensitive drum 11. Moved to the retracted position. The gear 81, the motor gear 82, and the motor 83 constitute the drive member 80.

  In the state shown in FIG. 3, the development unit 16B is in the retracted position immediately before the development of black is completed and the development by the development unit 16Y is started. In this state, the contact portion 66b of the support member 66 of the developing device 16B is positioned to face the cooling device 71, and the contact portion 66b contacts the one end portion 72a of the brush 72. In the development of the developing device 16B, the developing roller 53 rotates while contacting the regulating member 55 in order to form a thin toner layer on the developing roller 53, and heat due to friction accumulates in the regulating member 55. However, the heat moves to the heat radiating plate 73 via the support member 66 and the brush 72. The hot air radiated from the heat radiating plate 73 is blown into the pipe from the opening 74 a of the duct pipe 74, and is exhausted out of the image forming apparatus 1 by the fan 75.

  Next, the developing operation of the image forming apparatus 1 will be described. First, development is performed by the developing device 16B. As shown in FIG. 2, when the stirring member 56 rotates, the toner is splashed up in the toner containing portion 59 while being stirred. The splashed toner enters the passage portion 64 and is conveyed to the toner supply portion 58 via the supply roller 54. When the supply roller 54 further rotates, the toner is conveyed and held by the developing roller 53, and when the developing roller 53 rotates while contacting the regulating member 55, a thin layer of toner is formed on the developing roller 53. When a voltage is applied to the developing roller 53, the toner on the developing roller 53 is supplied to the photosensitive drum 11, and the electrostatic latent image on the photosensitive drum 11 is developed as a toner image. The toner that is not used for development and remains on the developing roller 53 is further rotated by the developing roller 53 and scraped by the supply roller 54 and returned to the toner supply unit 58.

  When the development by the developing device 16B is completed, the rotary rack 15 is rotated by the driving member 80 as shown in FIG. When the rotary rack 15 rotates, as shown in FIG. 3, the developing device 16B reaches the retracted position and stops there. In this retracted position, the developing roller 53 of the developing device 16B is separated from the photosensitive drum 11, and the support member 66 is in contact with the brush 72. When the support member 66 comes into contact with the brush 72, the heat accumulated in the regulating member 55 during development moves to the heat radiating plate 73 via the support member 66 and the brush 72. The hot air radiated from the heat radiating plate 73 is blown into the pipe from the opening 74 a of the duct pipe 74, and is exhausted out of the image forming apparatus 1 by the fan 75.

  Next, in yellow development, the surface of the photosensitive drum 11 is charged while rotating, and a yellow latent image is formed in a charged region by the laser unit. When the yellow latent image is formed and the rotary rack 15 is rotated counterclockwise in FIG. 3 by the driving member 80, the developing roller 53 of the developing device 16Y is moved to the developing position facing the photosensitive drum 11. Moving. Similar to the black development of the developing device 16B, the yellow development is performed. When the development is completed, the rotary rack 15 is rotated by the drive member 80, and the developing device 16Y reaches the retracted position and stops there. At this retracted position, the developing roller 53 of the developing device 16Y is separated from the photosensitive drum 11, and the support member 66 of the developing device 16Y contacts the brush 72. When the support member 66 comes into contact with the brush 72, the heat accumulated in the regulating member 55 of the developing device 16Y moves to the heat radiating plate 73 through the support member 66 and the brush 72. The hot air radiated from the heat radiating plate 73 is blown into the pipe from the opening 74 a of the duct pipe 74, and is exhausted out of the image forming apparatus 1 by the fan 75.

  Further, in magenta development, similarly to black development, when the developing unit 16M is in the retracted position after development, heat generated in the regulating member 55 of the developing unit 16M sequentially moves to the support member 66, the brush 72, and the heat radiating plate 73. Then, the air is blown into the pipe from the opening 74 a of the duct pipe 74 and is exhausted out of the image forming apparatus 1 by the fan 75.

  In the cyan development, similarly to the black development, when the developing unit 16C is in the retracted position after development, heat generated in the regulating member 55 of the developing unit 16C sequentially moves to the support member 66, the brush 72, and the heat radiating plate 73. Then, the air is blown into the pipe from the opening 74 a of the duct pipe 74 and is exhausted out of the image forming apparatus 1 by the fan 75.

  According to the first embodiment, the image forming apparatus 1 includes a developing roller 53 that is disposed in each of the developing devices 16B, 16Y, 16C, and 16M and that develops the electrostatic latent image formed on the photosensitive drum 11, and the developing roller. A regulating member 55 that abuts on the toner layer 53 and regulates the toner layer thickness; and a driving member 80 that rotates the rotary rack 15 to a developing position where each developing roller 53 sequentially faces the photosensitive drum 11. Further, the image forming apparatus 1 includes a support member 66 made of a material having a high thermal conductivity, in which an attachment portion 66a for fixing the regulating member 55 and a contact portion 66b exposed on the outer periphery of the developing device 16 are formed. The brush 72 has flexibility and can be contacted with the contact portion 66b of the support member 66, and has a high thermal conductivity. When the developing device 16 is rotated from the developing position and is at the next stop position, the contact portion 66b contacts the brush 72.

  According to this configuration, since the support member 66 to which the restriction member 55 is fixed comes into contact with the brush 72 having a high thermal conductivity, the frictional heat accumulated in the restriction member 55 due to friction with the developing roller 53 is reduced. Therefore, it is possible to suppress the temperature of the toner from being excessively increased and suppress the deterioration of the fluidity of the toner, thereby obtaining good development performance.

  Further, according to this configuration, when the cooling member is configured by the brush 72 and the rotary rack 15 rotates, the brush 72 sequentially contacts the support member 66 of each developing device 16B, 16Y, 16C, 16M. Since the heat of 55 moves to the brush 72 via the support member 66, it is not necessary to provide a cooling member for each of the developing devices 16B, 16Y, 16C, and 16M, and the apparatus has a simple configuration and is assembled to the developing device 16. Therefore, it is possible to reduce the number of parts.

  Further, according to this configuration, since the cooling member is configured by the brush 72 having flexibility and high thermal conductivity, there is no possibility that the rotational torque of the rotary rack 15 increases, and the rotary rack Even if the brush 72 comes into contact with the developing roller 53 during rotation 15, there is no possibility of damaging the surface of the developing roller 53.

  In addition, according to this configuration, when the developing device 16 is at the stop position, the contact portion 66b of the support member 66 contacts the brush 72, so that it is caused by friction with the developing roller 53 over a long period of stoppage. Since the frictional heat accumulated in the regulating member 55 moves to the brush 72 via the support member 66, the accumulated heat in the regulating member 55 can be surely removed.

  Further, according to this configuration, when the developing device 16 is rotated from the developing position and is in the next stop position, the contact portion 66b of the support member 66 contacts the brush 72, so Immediately after development in which frictional heat is accumulated in the regulating member 55 due to friction, that is, in a state where the amount of heat due to friction of the regulating member 55 is large, the heat of the regulating member 55 moves to the brush 72 via the support member 66. The accumulated heat of the regulating member 55 can be surely removed.

  Further, according to the first embodiment, the blower mechanism including the fan 75 and the duct pipe 74 and the heat radiating plate 73 are provided. A brush 72 is fixed to one surface 73 a of the heat radiating plate 73, an end surface 73 b of the heat radiating plate 73 faces the opening 74 a of the duct pipe 74, and the air blowing mechanism sucks air in the vicinity of the heat radiating plate 73.

  According to this configuration, the heat accumulated in the regulating member 55 moves to the heat radiating plate 73 via the support member 66 and the brush 72. The hot air radiated from the heat radiating plate 73 is blown into the pipe through the opening 74a of the duct pipe 74, and is exhausted out of the image forming apparatus 1 by the fan 75. There is no possibility that hot air stays in the image forming apparatus 1.

(Second Embodiment)
FIG. 5 is a side sectional view showing the configuration of the developing devices 16B, 16Y, 16C, and 16M provided on the rotary rack 15 and the cooling device 71 according to the second embodiment of the present invention. FIG. 5 shows a state in which the developing device 16B is in the developing position and the developing device 16C is in the cooling position. The toner storage states of the developing devices 16B, 16Y, 16C, and 16M, which are different from those in the first embodiment, will be described.

  As shown in FIG. 5, when the toner is sufficiently stored in each of the developing devices 16B, 16Y, 16C, and 16M, the developing device 16B is in a developing position where the developing roller 53B faces the photosensitive drum 11. In the developing device 16B, the toner 67B is stored in the toner storage portion 59B, and further, beyond the partition member 52B, the toner supply portion 58B is stored in an appropriate amount for development.

  In the developing unit 16C immediately after the end of the development, the developing unit 16C is located above the rotary rack 15 (upper side in FIG. 5), so that the toner 67C gathers in the center direction of the rotary rack 15, and the toner storage portion 59C and the toner supply Stored in part 58C. However, the toner 67C in the toner supply unit 58C is stored in a portion away from the regulating member 55C as compared with the developing device 16B.

  In the developing device 16M, the toner 67M flows into the toner supply unit 58M from the toner storage unit 59M, is stored in the supply roller 54M and the development roller 53M, and approaches the regulating member 55M. In the developing device 16Y, since the developing roller 53Y is positioned below in FIG. 5, the toner 67Y is stored in the supply roller 54Y and the developing roller 53Y, and is also stored in the regulating member 55Y.

  The cooling device 71 faces the developing device 16C located above in FIG. 5, and the brush 72 of the cooling device 71 contacts the support member 66C. If it does so, the heat | fever accumulate | stored in 55 C of control members will move to the heat sink 73 via 66 C of support members, and the brush 72. FIG. The hot air radiated from the heat radiating plate 73 is blown into the duct pipe 74 and is exhausted out of the image forming apparatus 1 by the fan 75.

  According to the second embodiment, the rotation of the rotary rack 15 causes the toners 67 of the developing units 16B, 16Y, 16C, and 16M to flow in the toner storage portions 59, and the developing unit 16C is positioned above the rotary rack 15. That is, when the toner 67C is at the position farthest from the regulating member 55C, the support member 66C comes into contact with the brush 72, so the heat of the regulating member 55C due to friction with the developing roller 53C is accommodated in the toner accommodating portion 59C. The toner does not move to the toner 67C but moves to the brush 72 through the support member 66C. Therefore, it is possible to suppress the toner 67C from being excessively heated, to suppress the deterioration of the toner fluidity, and to obtain good development performance.

  In the first and second embodiments, the configuration in which the brush 72 of the cooling device 71 is in contact with the support member 66 when the developing device 16 is at the stop position is shown. A configuration may be employed in which the brush 72 contacts each support member 66 when the rack 15 is rotating.

  Moreover, in the said 1st and 2nd embodiment, although the cooling member was comprised with the brush 72, this invention is not restricted to this, You may make a cooling member into a thin plate. In this case, if the thin plate does not have flexibility, when the rotary rack 15 rotates, it contacts the developing roller 53 and is damaged, but the thin plate faces the support member 66 in conjunction with the rotation of the rotary rack 15. If the configuration is such that the thin plate descends and contacts the support member 66 when the position is in the position, the developing roller 53 is not damaged.

  Moreover, in the said 1st and 2nd embodiment, although the cooling device 71 is one, this invention is not restricted to this, You may use two.

  Further, in the first and second embodiments, the fan 75 as the air blowing mechanism is provided at the rear stage of the duct pipe 74 and sucks hot air from the heat radiating plate 73. However, the present invention is not limited to this, and the fan radiates heat. You may make it arrange | position in the vicinity of the board 73. FIG. In this case, when air is blown from the fan to the heat radiating plate 73, the hot air from the heat radiating plate 73 circulates in the duct pipe 74.

  In the first embodiment, the support member 66 is in contact with the brush 72 at the retracted position after the completion of development, and the cooling device operates. However, the support member 66 is at the development position for developing other colors. 72 may be in contact with the cooling device.

  The present invention can be used for an image forming apparatus such as a copying machine, a printer, a facsimile machine, and the like provided with a rotary type developing device.

FIG. 1 is a schematic diagram illustrating an overall configuration of an image forming apparatus according to an embodiment of the present invention. These are side surface sectional drawings which show the structure of the developing device which is 1st Embodiment of this invention. These are side surface sectional drawings which show the structure of the developing device installed in the rotary rack which is 1st Embodiment of this invention, and a cooling device. These are top views which show the structure of the developing device and cooling device which were installed in the rotary rack which is 1st Embodiment of this invention. These are side surface sectional drawings which show the structure of the developing device and cooling device which were installed in the rotary rack which is 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Rotary developing unit 15 Rotary rack 15a Rotating shaft 16, 16B, 16Y, 16C, 16M Developer 51 Frame body 53 Developing roller 53b Axis 54 Supply roller 55 Restriction member 56 Stirring member 58 Toner supply part 59 Toner accommodation Department (container)
61 1st partition member (partition member 52)
62 Second partition member (partition member 52)
66 Support members 67B, 67Y, 67C, 67M Toner 71 Cooling device 72 Brush 73 Heat sink 74 Duct tube 75 Fan 80 Drive member

Claims (6)

A rotary rack provided with a plurality of developing units at different positions in the circumferential direction, a developing roller that carries a developer and develops an electrostatic latent image formed on the image carrier, and abuts against the developing roller for development. An image forming apparatus comprising: a regulating member that regulates the layer thickness of the agent; and a driving member that rotates the rotary rack to a developing position where the developing roller sequentially faces the image carrier.
A support member made of a heat conductive material in which a mounting portion for fixing the regulating member and a contact portion exposed on the outer periphery of the developing device is formed; and a cooling member that can contact the contact portion.
The image forming apparatus, wherein the contact portion contacts the cooling member at a predetermined position of the developing device.   The image forming apparatus according to claim 1, wherein the cooling member is formed of a brush having flexibility and made of a heat conductive material. A blower mechanism having a fan and a duct pipe, and a heat radiating plate formed with one end portion for fixing the cooling member and the other end portion facing the duct pipe and extending in the longitudinal direction of the developing device. Prepared,
The image forming apparatus according to claim 1, wherein the air blowing mechanism causes air in the vicinity of the heat radiating plate to flow.   The image forming apparatus according to claim 1, wherein the predetermined position is a position where the rotary rack is stopped.   The developing device includes an accommodating portion for accommodating a developer, and the developer flows in the accommodating portion by the rotation of the rotary rack, and the predetermined position is a position where the developer is farthest from the regulating member. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.   The image forming apparatus according to claim 4, wherein the predetermined position is a stop position next to a development position.

Images