JP2010243681A - Developing device for image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device for an image forming apparatus which effectively dissipates heat close to the developing device of the image forming apparatus and cools it. <P>SOLUTION: Two conveying screws 34 and 35 are arranged in the developer storage section 32a of the developing device 31. While being mixed and agitated by the conveying screws 34 and 35, toner is conveyed in a circle form and is also charged to a predetermined potential. The end of each of the conveying screws 34 and 35, with a developing roller 32 and a sealing member attached thereto projects beyond the holding member 37 and a gear is attached to it and engages with a drive gear 36. A fan 43 is disposed on the gear at the shaft end of each of the conveying screws 34 and 35 to generate an air flow. The conveying screws 34 and 35, bearings 34b and 35b, and holding member 37 are made of a heat-conductive metal material. The heat generated by the conveying screws, bearing, etc, and heat generated near the sealing member are transmitted quickly to the holding member 37 and cooled by a current of air. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for an image forming apparatus such as an electronic copying machine or a complex machine thereof, and more particularly to a developing device for an image forming apparatus that can efficiently dissipate heat generated in the developing device.

  In an electrophotographic image forming apparatus, an image carrier is uniformly charged by a charging device, an image latent image is formed on the image carrier charged by an exposure device, and an image latent image on the image carrier is developed by a developing device. The image is developed with toner to form a toner image, the toner image formed on the image carrier is transferred to a recording paper by a transfer device, and the toner transferred onto the recording paper by a fixing device is heated and melted. Then, a fixing process is performed and an image print is created. After the toner image on the image carrier is transferred to a recording paper or the like, the remaining toner is removed by a cleaning device.

  Among these, a unit in which constituent members including an image carrier, a charging device, an exposure device, a developing device, a transfer device, and a cleaning device are combined into one is called a process unit and is widely used.

  On the other hand, full-color image forming apparatuses have recently become widespread and widely used, and there is a need for downsizing and speeding up of the apparatus, as well as long life, long reliability, long image quality, and low price. As a result, development and design are being carried out accordingly.

  Among these, as for the developing device arranged inside the process unit, there is one that is used by loading a developer composed of a mixture of carrier and toner inside the developing device, but in order to prevent this developer from leaking outside, The opening is sealed with a seal member. In this case, as the size and speed of the apparatus are required, the toner contained in the developer is melted and solidified by the heat generated by the seal member provided in the opening of the developing device, thereby reducing the image quality. There is a possibility.

  As a countermeasure, a plurality of cooling means for cooling the vicinity of the developing device have been proposed. The first one is a drive shaft that contacts a resin gear that drives a stirring and conveying body that stirs and conveys the developer. The thing which made the part metal and improved heat dissipation is proposed (refer patent document 1).

  In addition to the first configuration, the second one has been proposed in which a stirring and conveying body that agitates and conveys the developer is used as a hollow shaft for cooling by flowing a fluid therein (see Patent Document 1). .

  As the third one, a heat transfer means has been proposed in which the agitating and conveying body itself for agitating and conveying the developer is used (see Patent Document 2).

  As the fourth one, there has been proposed one in which a stirring and conveying body that stirs and conveys the developer is deformed or a heat dissipation fan is provided (see Patent Document 3).

JP 2005-140968 A JP 2000-19919 A JP 2001-66892 A

  It has been found that the cooling means for cooling the vicinity of the developing device of the image forming apparatus disclosed in Patent Document 1 cannot retain a sufficient heat dissipation effect because heat is retained by the resin gear. Further, the cooling means disclosed in the above-mentioned Patent Document 1 for cooling by flowing a fluid inside using a stirring conveyance body as a hollow shaft requires a pump and a heat exchange device for flowing the fluid, and increases space and manufacturing cost. There are inconveniences such as results.

  In the case where the stirring and conveying body itself disclosed in Patent Document 2 is used as a heat dissipation means, it is necessary to enlarge a portion for dissipating heat, and the apparatus becomes large accordingly. In addition, it is necessary to enlarge the part that dissipates heat in the agitating / conveying body disclosed in Patent Document 2 or provided with heat-dissipating fins. There is an inconvenience. The present invention aims to solve the above problems.

  SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and the invention according to claim 1 stirs and conveys the developing roller rotatably disposed inside the developer accommodating portion and the developer disposed inside the developer accommodating portion. A plurality of conveying screws, a developing roller gear mounted on the shaft end of the developing roller, a conveying screw gear mounted on the shaft end of the plurality of conveying screws, and a drive gear that drives the developing roller gear and the conveying screw gear. A developing device for an image forming apparatus in which a bearing for supporting the developing roller shaft and the plurality of conveying screw shafts and a holding member for holding the bearing are disposed inside the developing device housing, wherein the bearing and the holding member are A developing device for an image forming apparatus, wherein the developing device is made of a material having good heat conduction.

  The developing device housing includes a toner smoke suction port for sucking the toner smoke and a toner suction path for conveying the sucked toner smoke to the outside of the developing device housing.

  A seal member for preventing leakage of toner smoke may be attached to the shaft end of the conveying screw.

  The transport screw gear mounted on the shaft end of the transport screw may be provided with a fan that generates an air flow inside the developing device housing.

  Further, the holding member may be arranged at a position in contact with the air flow generated by the fan.

  According to the present invention, since the bearing and the holding member for supporting the developing roller and the conveying screw are made of a material having good heat conduction, the heat near the developing device of the image forming apparatus passes through the developing roller and the conveying screw. Although transmitted to the bearing and the holding member, since the bearing and the holding member are made of a material having good heat conduction, a sufficient heat dissipation effect can be obtained.

  A seal member for preventing leakage of toner fumes is attached to the shaft end of the conveying screw, and a toner suction path for sucking the toner fumes to the developing device housing and conveying it to the outside of the developing device housing Therefore, not only the vicinity of the developing device is not soiled by the toner fumes, but also the air inside the developing device housing is discharged to the outside through the toner fuming suction port, and the vicinity of the developing device of the image forming apparatus is cooled. Can do.

  Further, by providing a fan on the conveying screw gear mounted on the shaft end of the conveying screw, an air flow can be generated inside the developing device housing, and cooling in the vicinity of the developing device of the image forming apparatus can be promoted.

1 is a diagram illustrating an outline of a configuration of a tandem full-color image forming apparatus. FIG. The perspective view explaining the whole structure of a developing device. FIG. 3 is a cross-sectional view of the developing device. The perspective view explaining the structure of the drive mechanism side edge part of a developing device. The front view explaining the structure of the drive mechanism side edge part of a developing device. The figure explaining the structure of the edge part of a conveyance screw. The figure explaining the arrangement | positioning of a sealing member and a conveyance screw gear (the 1). The figure explaining the arrangement | positioning of a sealing member and a conveyance screw gear (the 2).

[Outline of configuration of full-color image forming apparatus]
Hereinafter, an embodiment in which the present invention is applied to a tandem full-color image forming apparatus will be described. In the following description, the full-color image forming apparatus may be simply referred to as an image forming apparatus.

  FIG. 1 is a diagram for explaining an outline of the configuration of a tandem-type full-color image forming apparatus 10 to which the present invention is applied. Since the tandem-type full-color image forming apparatus itself is a known configuration, only the outline of the configuration is briefly described. explain.

  In FIG. 1, image forming units 11, 12, 13, and 14 that form images of yellow (Y), magenta (M), cyan (C), and black (K) colors are a driving roller 15 and a driven roller 16. The intermediate transfer belt 17 is arranged in series under an intermediate transfer belt 17 that is an intermediate transfer member laid between the two, and the intermediate transfer belt 17 is fixed in the direction of arrow a by a driving roller 15 driven through a motor and a driving device (not shown). It is configured to move at speed.

  Each of the image forming units 11 to 14 is provided with a photosensitive member, a charging device, an exposure device, and a developing device, each of which is an image carrier. However, the configuration thereof is not the subject of the present invention, and thus description thereof is omitted here.

  Each of the image forming units 11 to 14 is provided with a photoconductor cleaning device that is a cleaning device for cleaning the transfer residual toner on the photoconductor. The photoconductor cleaning device includes a known blade cleaning device or brush cleaning device. Devices and other configurations can be used. The untransferred toner on the photoconductor removed by the photoconductor cleaning device is conveyed to a waste toner bottle through a toner conveyance path (not shown).

  The image signal processing device 20 receives an image signal output from a scanner (not shown) or an image signal output from a personal computer or the like, and corresponds to the color of the image to be formed in the exposure device of each image forming unit 11-14. The output image signal is output. A paper feeding unit 21 is disposed below the image signal processing device 20.

  Each of the image forming units 11 to 14 is not provided with a transfer device. Instead, the primary transfer rollers 11T, 12T, 13T, and 14T are disposed on the opposite side of the image forming units 11 to 14 with the intermediate transfer belt 17 interposed therebetween. Is arranged.

  Further, a secondary transfer roller 18 is disposed at a position facing the driven roller 16 with the intermediate transfer belt 17 interposed therebetween, and a belt cleaning device 19 is disposed at a position facing the drive roller 15 with the intermediate transfer belt 17 interposed therebetween. ing.

  A fixing device 22 for fixing the toner image transferred to the recording paper is disposed downstream of the secondary transfer roller 18 in the recording paper conveyance direction. 24 is arranged.

  The operation of the full-color image forming apparatus 10 will be briefly described. When the power is turned on, the intermediate transfer belt 17 starts moving at a constant speed in the direction of arrow a. An image forming operation is started, and yellow (Y), magenta (M), cyan (C), and black (K) toner images are formed on the photoreceptors of the image forming units 11 to 14, respectively. . The yellow (Y) toner image is transferred onto the intermediate transfer belt 17 by the operation of the primary transfer roller 11T, and the magenta (M) toner image is superimposed and transferred thereon by the operation of the primary transfer roller 12T. Thereafter, in the same manner, cyan (C) and black (K) toner images are sequentially superimposed and transferred to form a full-color toner image on the intermediate transfer belt 17.

  The recording paper P is fed from the paper feeding unit 21 in accordance with the timing at which the full-color toner image formed on the intermediate transfer belt 17 reaches the position of the secondary transfer roller 18, and the secondary transfer device is a secondary transfer device. The full color toner image on the intermediate transfer belt 17 is transferred onto the recording paper P by the operation of the transfer roller 18. Thereafter, the recording paper P is conveyed to the fixing device 22, and the toner image on the recording paper P is fixed, and is discharged to the paper discharge tray 24 through the paper discharge roller 23.

  Although transfer residual toner remains on the intermediate transfer belt 17, it interferes with the next image formation. Therefore, the surface of the intermediate transfer belt 17 is cleaned by the belt cleaning device 19 and the transfer residual toner is removed.

[Developer configuration]
Next, the configuration of the developing device incorporated in each of the image forming units 11 to 14 of the full color image forming apparatus 10 will be described. Since the configuration of the developing device is common to the image forming units 11 to 14, the developing device 31 of the image forming unit 11 will be described here.

  2 is a perspective view of the overall configuration of the developing device 31, FIG. 3 is a cross-sectional view of the developing device 31, FIG. 4 is a perspective view illustrating the configuration of the driving mechanism at the end of the developing device 31, and FIG. FIG. 6 is a front view for explaining the configuration of the driving mechanism at the end of FIG. 6A, showing the meshing state of the developing roller gear 32b, the conveying screw gears 34a and 35a, and the driving gear 36 inside with the holding member 37 removed.

  As the developing roller 32 of the developing device 31, a developing roller 32 having a configuration in which a developing sleeve is rotatably fitted on the outside of the magnetic rod is used. The developing device 31 is provided with a developing roller 32 in the center, and the image latent image formed on the surface of the photosensitive member in contact with the surface of the photosensitive member of the image forming unit 11 is adhered to the developing roller 32 from a mixture of magnetic carrier and toner. It develops with the toner contained in the developing agent. Note that there are toner-only developers that do not use a magnetic carrier, but here a description will be given assuming that a developer made of a mixture of a magnetic carrier and toner is used.

  The developing device 31 is assembled in the developing device housing 31a. A toner replenishing port 33 is provided at one end of the developing device housing 31a in the longitudinal direction, and toner is formed so as to surround the developing roller 32 from a toner replenishing bottle (not shown). The developer accommodating portion 32a is replenished.

  Two conveying screws 34 and 35 are arranged inside the developer accommodating portion 32a, and the toner replenished from the toner replenishing port 33 is mixed and stirred with the magnetic carrier by the conveying screws 34 and 35, and the developer accommodating portion. It is circulated and conveyed throughout the interior of 32a and charged to a predetermined potential, and adheres to the surface of the developing roller 32 to form a magnetic brush.

  The conveying screws 34 and 35 are rotatably supported by bearings 34b and 35b, respectively, and the bearings 34b and 35b are held at the end of the developing device housing 31a by a holding member 37 (see FIGS. 4 and 5).

  The rotating shaft of the developing roller 32 and the end portions of the conveying screws 34 and 35 protrude from the holding member 37, and the developing roller gear 32 b provided at the end portion of the rotating shaft of the developing roller 32 and the end portions of the conveying screw 34. The three gears of the conveying screw gear 34 a provided at the end of the conveying screw 35 and the conveying screw gear 35 a provided at the end of the conveying screw 35 are engaged with the drive gear 36.

  By driving a drive gear 36 connected to a drive source (not shown), the developing roller 32 and the conveying screws 34 and 35 are simultaneously rotated. A seal member 38 for preventing the toner fumes generated by the rotation of the conveying screws 34 and 35 from leaking to the outside is disposed at the shaft ends of the conveying screws 34 and 35 disposed inside the developer accommodating portion 32a. Has been.

  When the driving gear 36 is driven by a driving source (not shown) and the developing roller 32 and the conveying screws 34 and 35 are rotated, toner smoke is generated, and the end of the conveying screws 34 and 35 is exposed to the outside of the developing device housing 31a. Leakage occurs and adheres to a charging device or the like disposed inside the image forming unit 11 to cause charging failure and image failure of the photosensitive member. Therefore, a seal member 38 is disposed at the shaft ends of the conveying screws 34 and 35. However, since this is not sufficient, it is necessary to suck the generated toner fumes and discharge them to the outside.

  For this reason, in the vicinity of the left and right ends of the developing roller 32 of the developing device housing 31a, a fuming toner suction port 40 for sucking toner fumes is provided, and development is performed via a toner suction path 41 provided in the developing device housing 31a. The toner is discharged to the outside of the developing device housing 31a from the toner discharge port 42 at the end of the device housing 31a, and finally discharged to a waste toner bottle of an image forming apparatus (not shown).

  In the above configuration, the two conveying screws 34 and 35, the bearings 34b and 35b, and the holding member 37 are made of a material having good thermal conductivity, for example, a metal material such as stainless steel, and heat generated by the conveying screw or the bearing, In addition, heat generated in the vicinity of the seal member is promptly transmitted to the holding member 37 and can be cooled by an air flow described later.

  FIG. 6 is a diagram for explaining the configuration of the end of the transport screw 34. The transport screw gear 34 a is provided at the end of the transport screw 34, and the bearing 34 b of the transport screw gear 34 a is held by the developing device housing by the holding member 37. As described above, it is held at the end of 31a. Here, a fan 43 is attached to the side surface of the conveying screw gear 34a, and an air flow along the conveying screw is generated by the rotation of the conveying screw gear 34a. As a result, the toner smoke leaked from the end of the conveying screw 34 is sucked into the smoke toner suction port 40, discharged to the outside of the developing device housing 31 a through the toner suction path 41, and finally image formation (not shown) It is discharged into the waste toner bottle of the device.

  The configuration of the end portion of the conveying screw 35 is the same as the configuration of the end portion of the conveying screw 35, and thus detailed description thereof is omitted.

  7 shows the arrangement of the sealing member 38 provided at the shaft end of the conveying screw 34, the conveying screw gear 34a provided with the fan 43, and the toner suction path 41, and the toner generated by the air flow A generated by the fan 43. It is a figure explaining the 1st example of the flow of smoke.

  As shown in FIG. 7, although not shown in FIG. 7, in addition to the developing roller 32, the conveying screw 34 is rotatable inside a developer accommodating portion 32 a by a bearing 34 b provided on a holding member 37. It is held at the end of the developing device housing 31a.

  A seal member 38 is mounted in the vicinity of the shaft end portion of the conveying screw 34, and toner fumes leak from the developer accommodating portion 32a to the outside through the shaft end portion of the conveying screw 34 disposed inside the developer accommodating portion 32a. In addition, an air flow A along the conveying screw is generated by the fan 43 provided on the conveying screw gear 34a, and the flow direction is changed by the holding member 37 and the air is sucked into the toner jet port 40. The toner fumes are discharged to the outside of the developing device housing 31a, and finally discharged to a waste toner bottle of an image forming apparatus (not shown). The air flow A along the conveying screw absorbs the heat generated in the vicinity of the seal member, and hits the holding member 37 to transmit the heat to the holding member 37, thereby cooling the air flow A and lowering the temperature in the vicinity of the developing device housing 31a. Can be made.

  FIG. 8 shows the arrangement of the sealing member 38 provided at the shaft end of the conveying screw 34, the conveying screw gear 34 a provided with the fan 43, and the toner suction path 41, and the air generated by the air flow A generated by the fan 43. It is a figure explaining the 2nd example of a flow and a flow of toner fume.

  In the second example of the air flow A and the flow of toner fumes by the fan 43 shown in FIG. 8, the flow direction is changed by the holding member 37, and the flow direction is changed before the holding member 37, so 40 shows that it is sucked. The air flow A can absorb the heat generated in the vicinity of the seal member and reduce the temperature of the developing device housing 31a.

  In the above embodiment, the smoke toner suction path 41 is provided in the developing device housing 31a. However, the present invention is not limited to this and may be provided on the image forming apparatus side.

  An image forming apparatus provided with a cooling means for cooling the vicinity of the developing device, wherein a fan is formed at a shaft end portion of the conveying screw disposed inside the developing device housing 31a, and the conveying screw is rotated by the rotation of the conveying screw. Along the air flow A, the temperature of the developing device housing 31a is lowered.

DESCRIPTION OF SYMBOLS 10 Full-color image forming apparatus 11, 12, 13, 14 Image forming unit 11T, 12T, 13T, 14T Primary transfer roller 15 Driving roller 16 Driven roller 17 Intermediate transfer belt 18 Secondary transfer roller 19 Belt cleaning apparatus 20 Image signal processing apparatus 21 Paper feeding unit 22 Fixing device 23 Paper discharge roller 24 Paper discharge tray 31 Developing device 31a Developing device housing 32 Developing roller 32a Developer container 32b Developing roller gear 33 Toner supply port 34, 35 Conveying screw 34a, 35a Conveying screw gear 34b, 35b Bearing 36 Drive gear 37 Holding member 38 Seal member 40 Smoke toner suction port 41 Toner suction path 42 Smoke toner discharge port 43 Fan

Claims (5)

A developing roller rotatably disposed within the developer accommodating portion, a plurality of conveying screws that stir and convey the developer disposed within the developer accommodating portion, and a development mounted on the shaft end of the developing roller A roller gear, a conveyance screw gear mounted on shaft ends of a plurality of conveyance screws, a drive gear for driving the development roller gear and the conveyance screw gear, a bearing for supporting the development roller shaft and the plurality of conveyance screw shafts, and the bearing Is a developing device of the image forming apparatus disposed inside the developing device housing,
The developing device of an image forming apparatus, wherein the bearing and the holding member are made of a material having good heat conduction. The image forming apparatus according to claim 1, wherein the developing device housing includes a toner fuming suction port that sucks toner fumes and a toner sucking path that conveys the sucked toner fumes to the outside of the developing device housing. Development device. 2. The developing device for an image forming apparatus according to claim 1, wherein a seal member for preventing leakage of toner smoke is attached to a shaft end of the conveying screw. The developing device of the image forming apparatus according to claim 1, wherein a fan that generates an air flow is attached to the inside of the developing device housing on the conveying screw gear attached to the shaft end of the conveying screw. . The developing device of an image forming apparatus according to claim 1, wherein the holding member is disposed at a position in contact with an air flow generated by the fan.

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