JP4882418B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic image forming apparatus such as a printer, a copier, a facsimile machine, or a multi-function machine having a combination of these functions.

  In recent image forming apparatuses, as the speed of image formation increases, toner dust (hereinafter referred to as “smoke toner”) tends to scatter from the developing nip portion between the image carrier and the developing roller. Contamination of the apparatus with dust toner is a problem.

In view of such a problem, for example, as described in Patent Document 1 and Patent Document 2, a duct for sucking dust toner is provided in a state where the suction port is close to the developing nip portion, and is connected to the duct. There has been proposed a technique for forcibly sucking dust toner with a suction fan.
Japanese Patent Publication No. 8-14735 JP 2002-268377 A

  However, as described in Patent Document 1 and Patent Document 2, if the dust toner is forcibly sucked in the vicinity of the development nip portion, the toner that originally contributes to the development is also sucked. There is a drawback in that the amount of toner consumption increases because it must be carried on a roller.

  In addition, since a large amount of dust toner is sucked into the duct, the filter for collecting the dust toner is likely to be clogged, or the volume of the collection unit for collecting the dust toner must be increased. There is also a problem.

  Therefore, the present invention can efficiently collect the dust toner, and can prevent an increase in toner consumption, a decrease in the life of the dust toner collecting filter, and an increase in the volume of the dust toner collecting portion. An object is to provide an image forming apparatus.

In order to solve the above problems, an image forming apparatus according to claim 1 of the present invention provides:
An image carrier that carries an electrostatic latent image, and a developer carrier that is disposed opposite to the image carrier to perform development by attaching toner to the electrostatic latent image,
A collecting member that collects dust toner generated at a developing nip portion between the image carrier and the developer carrier using an air flow generated in accordance with the operation of the image forming apparatus,
A hollow recovery portion provided along the longitudinal direction of the developer carrier near the upper side of the development nip portion;
And because of the introduction opening for introducing the Konakemuri toner to the hollow collecting unit,
An exhaust opening for discharging the air flow introduced into the hollow recovery portion so as to guide upward ,
End damming members for damming the airflow flowing from the longitudinal intermediate portion of the developer carrier toward both ends in the vicinity of the upper side of the developing nip portion are provided at both longitudinal ends of the developing nip portion,
Predetermined position of the member provided on the upper side of the collecting member, or at a position above side than the introduction opening in the collecting member, away from the developing nip portion dammed by stop member dam said end An airflow introduction damming portion for damming the airflow pushed upward and guiding the airflow to the introduction opening is provided so as to project the tip on the image carrier side close to or in contact with the image carrier. And
The introduction opening is provided at a portion on both ends in the longitudinal direction of the hollow recovery portion above the development nip portion and facing the image carrier.
The exhaust opening is provided on an upper surface portion at both ends in the longitudinal direction of the hollow recovery portion, and is covered with a filter for collecting and collecting the dust toner .

  Here, the “smoke toner” refers to toner dust that scatters from the development nip during development.

An image forming apparatus according to a second aspect of the present invention includes an endless intermediate transfer belt having a horizontal portion at least on the lower side, and the image carrier and the developer carrier on the lower side of the horizontal portion, As the intermediate transfer belt is driven to rotate, the airflow flowing along the moving direction of the intermediate transfer belt below the horizontal portion is blocked by the image carrier and guided to the developing nip portion below. It is characterized by being arranged.

In the image forming apparatus according to claim 3 of the present invention, the developing device having the developer carrying member and the collecting member is guided by a guide member provided in the main body of the image forming device and is detachable. In the mounted state of the developing device, the upper surface of the hollow recovery portion is configured to contact the lower surface of the guide member, the exhaust opening is provided at both longitudinal ends of the upper surface of the hollow recovery portion, Ventilation openings for passing the airflow discharged from the hollow recovery part through the exhaust opening are provided at both longitudinal ends corresponding to the exhaust opening. And

In the image forming apparatus according to claim 4 of the present invention, the guide member has a duct portion for allowing the airflow supplied through the ventilation opening to pass through, and the duct portion is provided in the duct portion. It is connected to a suction fan that sucks air.

  According to the present invention, the dust toner generated in the developing nip portion can be collected by utilizing the airflow generated in the apparatus as the image forming apparatus is operated. Thus, it is possible to prevent the toner that contributes to the development from being sucked as in the conventional case, and it is possible to efficiently collect the dust toner.

  Therefore, while preventing contamination of the apparatus by the dust toner, the toner consumption increases, the life of the dust toner collecting filter is shortened, and the volume of the dust toner collecting unit is increased. Conventional problems can be solved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, terms indicating a specific direction and position (for example, “up”, “down”, “right”, “left” and other terms including those terms) are used as necessary. These terms are used for easy understanding of the invention with reference to the drawings, and the technical scope of the present invention is not limited by the meaning of these terms.

  FIG. 1 shows an image forming apparatus according to a first embodiment of the present invention. The image forming apparatus shown in FIG. 1 is a tandem color laser printer. However, the present invention can also be applied to an image forming apparatus other than a printer. For example, the present invention can be applied to a copier, a facsimile machine, or a multi-function machine having a combination of functions such as a printer, a copier, and a facsimile machine. good. Further, the present invention does not prevent application to a color image forming apparatus or a monochrome image forming apparatus of a system other than the tandem system.

  The image forming apparatus shown in FIG. 1 includes an endless intermediate transfer belt 4 at substantially the center inside the image forming apparatus main body 2. The intermediate transfer belt 4 is supported on the outer peripheral portion of the pair of rollers 6 and 8 so as to have a horizontal portion in the vertical direction, and is driven to rotate counterclockwise in the drawing. One roller 6 is connected to a drive motor (not shown), and the other roller 8 is driven to rotate as the roller 6 rotates.

  A secondary transfer device 36 and an intermediate transfer belt cleaning device 10 are disposed outside the intermediate transfer belt 4. A nip portion between the secondary transfer device 36 and the intermediate transfer belt 4 forms a secondary transfer region 38. The cleaning blade 12 provided in the intermediate transfer belt cleaning device 10 is provided in contact with the portion of the intermediate transfer belt 4 supported by the roller 8 at the tip, and the edge of the cleaning blade 12 causes the post-secondary transfer. The toner remaining on the surface of the intermediate transfer belt 4 is scraped off.

  Below the intermediate transfer belt 4, four image forming units 14Y, 14M, 14C, and 14K corresponding to the respective colors of yellow (Y), magenta (M), cyan (C), and black (K) are intermediate transfer belts. 4 are arranged side by side along the lower horizontal portion.

  The image forming units 14Y, 14M, 14C, and 14K respectively include photosensitive drums 16Y, 16M, 16C, and 16K as image carriers. Each of the photosensitive drums 16Y, 16M, 16C, and 16K is rotationally driven in a clockwise direction in the drawing by a drive motor (not shown).

  Around each of the photosensitive drums 16Y, 16M, 16C, and 16K, the chargers 18Y, 18M, 18C, and 18K, and the developing devices 20Y, 20M, 20C, and 20K are sequentially arranged along the rotation direction (clockwise direction in the drawing). The primary transfer devices 22Y, 22M, 22C, and 22K facing the photosensitive drums 16Y, 16M, 16C, and 16K with the intermediate transfer belt 4 interposed therebetween, and the photosensitive member cleaning blades 24Y, 24M, 24C, and 24K are arranged, respectively. ing. A light source device 26 is disposed below the four image forming units 14Y, 14M, 14C, and 14K.

  As shown in FIG. 2, the image forming units 14Y, 14M, 14C, and 14K include photosensitive drums 16Y, 16M, 16C, and 16K, chargers 18Y, 18M, 18C, and 18K, and cleaning blades 24Y, 24M, 24C, and 24K. The drum unit sections 60Y, 60M, 60C, and 60K and the developing devices 20Y, 20M, 20C, and 20K are provided. The developing devices 20Y, 20M, 20C, and 20K and the drum unit portions 60Y, 60M, 60C, and 60K are guided by a guide member 94 provided in the image forming apparatus main body 2 and are detachable.

  Each of the developing devices 20Y, 20M, 20C, and 20K contains yellow, magenta, cyan, and black toners. As the primary transfer devices 22Y, 22M, 22C, and 22K, various contact chargers such as blades, rollers, or brushes are preferably used. By using these contact chargers, generation of ozone can be avoided. Advantages such as being resistant to fluctuations in the temperature and humidity environment and improving image quality can be obtained.

  Returning to FIG. 1, a paper feed cassette 28 is detachably disposed at the bottom of the image forming apparatus main body 2. The sheet (recording medium) 30 loaded and accommodated in the sheet feeding cassette 28 is the uppermost one by the rotation of the sheet feeding roller 32 disposed at a position facing the vicinity of the front end of the sheet 30 loaded in the sheet feeding cassette 28. Are sent one by one to the conveyance path 56.

  The conveyance path 56 is connected to the nip portion 34 of the registration roller pair, the secondary transfer region 38, the nip portion 50 of the fixing roller 42 and the pressure roller 44 in the fixing device 40, and the nip portion of the discharge roller pair. It extends through the section 52 to a paper discharge section 54 provided at the top of the image forming apparatus main body 2. In addition, roller heaters 46 and 48 are provided inside the fixing roller 42 and the pressure roller 44, respectively.

  Next, an operation for forming a color image using the image forming apparatus will be described. When the photosensitive drums 16Y, 16M, 16C, and 16K of the image forming units 14Y, 14M, 14C, and 14K and the intermediate transfer belt 4 are started to rotate, and the intermediate transfer belt 4 passes a predetermined position, the image forming units Image formation is started at a predetermined timing in 14Y, 14M, 14C, and 14K.

  The image forming in each image forming unit 14Y, 14M, 14C, 14K will be specifically described. First, laser light is emitted from the light source device 26 at the predetermined timing to expose the photosensitive drums 16Y, 16M, 16C, and 16K, and the driving of the developing devices 20Y, 20M, 20C, and 20K is started. At a predetermined timing, a bias having a polarity opposite to that of the toner is applied to the primary transfer devices 22Y, 22M, 22C, and 22K.

  When the photosensitive drums 16Y, 16M, 16C, and 16K are exposed, electrostatic latent images for the respective color images are formed on the photosensitive drums 16Y, 16M, 16C, and 16K, and the electrostatic latent images are developed. The image is visualized by toner of each color supplied from the devices 20Y, 20M, 20C, and 20K. The toner images of the respective colors formed on the photosensitive drums 16Y, 16M, 16C, and 16K in this way are rotated by the photosensitive drums 16Y, 16M, 16C, and 16K, and the primary transfer device 22Y with the intermediate transfer belt 4 interposed therebetween. , 22M, 22C, and 22K, the primary transfer area is transferred onto the intermediate transfer belt 4 from the photosensitive drums 16Y, 16M, 16C, and 16K in the order of yellow, magenta, cyan, and black. .

  After the primary transfer, the toner remaining on the photosensitive drums 16Y, 16M, 16C, and 16K reaches the contact portion between the photosensitive drums 16Y, 16M, 16C, and 16K and the cleaning blades 24Y, 24M, 24C, and 24K. The surfaces of the photosensitive drums 16Y, 16M, 16C, and 16K are cleaned by being scraped off by the edges of the cleaning blades 24Y, 24M, 24C, and 24K. The developing devices 20Y, 20M, 20C, and 20K of the image forming units 14Y, 14M, 14C, and 14K are stopped at a predetermined timing after the primary transfer.

  Further, a bias having a polarity opposite to that of the toner is applied to the secondary transfer device 36 at a predetermined timing during the driving of the developing devices 20Y, 20M, 20C, and 20K of the image forming units 14Y, 14M, 14C, and 14K.

  The superimposed toner images of four colors are conveyed to the secondary transfer region 38 by the intermediate transfer belt 4. On the other hand, the paper 30 accommodated in the paper feed cassette 28 is conveyed to the secondary transfer area 38 in accordance with the timing. When the four-color toner images are secondarily transferred from the intermediate transfer belt 4 to the paper 30 in the secondary transfer region 38, the paper 30 on which the four-color toner images have been transferred is further downstream in the conveyance path 56. After the toner image is mixed by the fixing device 40 and the toner image is fixed to the paper 30, it is sent out to the paper discharge unit 54 by the paper discharge roller 53.

  Thereafter, after the intermediate transfer belt 4 is cleaned as post-processing, the rotation of the photosensitive drums 16Y, 16M, 16C, and 16K and the intermediate transfer belt 4 is stopped.

  Hereinafter, the configurations of the developing devices 20Y, 20M, 20C, and 20K and the peripheral members will be described. Since the yellow, magenta, cyan, and black developing devices 20Y, 20M, 20C, and 20K all have the same configuration, the yellow developing device 20Y shown in FIGS. 2 to 4 will be described as a representative.

  2 and 3 (b) show one end portion in the longitudinal direction of the developing device 20Y, and FIG. 3 (a) shows an intermediate portion in the longitudinal direction of the developing device 20Y. Note that the structure of the other end portion in the longitudinal direction of the developing device 20Y is the same as the structure of the one end portion in the longitudinal direction, and thus illustration is omitted.

  The developing device 20Y has a developing roller 62 as a developer carrying member disposed opposite to the photosensitive drum 16Y for carrying out development by attaching toner to the electrostatic latent image on the photosensitive drum 16Y, and the developing roller 62 carries the developing roller 20Y. A regulating blade 68 for regulating the layer thickness of the toner, a supply roller 64 for supplying the toner to the developing roller 62, an agitation roller 66 for agitating the toner in the toner accommodating portion 72, and And a housing 70 for holding the developing roller 62, the regulating blade 68, the supply roller 64, the stirring roller 66, and the like.

  The photosensitive drum 16Y and the developing device 20Y are arranged in the moving direction of the intermediate transfer belt 4 on the lower side of the lower horizontal portion as the intermediate transfer belt 4 is rotationally driven on the lower side of the lower horizontal portion of the intermediate transfer belt 4. The airflow flowing along the photosensitive drum 16 </ b> Y is blocked by the photosensitive drum 16 </ b> Y and guided to the lower developing nip 74.

  End seals 100 for preventing toner leakage from the developing device 20Y are fixed to the housing 70 at both ends in the longitudinal direction of the developing device 20Y. The end seal material 100 is disposed at both ends in the longitudinal direction of the developing nip portion 74 in the attached state of the developing device 20Y, and blocks the airflow flowing from the intermediate portion in the longitudinal direction of the developing roller 62 toward both ends in the vicinity of the developing nip portion 74. It functions as an end damming member to be stopped. Note that the end damming member may be formed of a member other than the end seal member 100.

  Further, the developing device 20Y collects dust toner generated at the developing nip 74 between the photosensitive drum 16Y and the developing roller 62 by using an air flow generated with the operation of the image forming apparatus. 80.

  The collection member 80 is provided on the upper side of the developing roller 62 along the longitudinal direction of the developing roller 62, and is disposed in the vicinity of the developing nip 74 when the developing device 20Y is attached.

  The recovery member 80 includes a rail member 82 having a recess 84 that opens upward, and a seal member 88 that closes the upper end opening of the recess 84.

  The recovery member 80 includes a hollow recovery portion 86 for containing the recovered dust toner, and the hollow recovery portion 86 is constituted by the concave portion 84 and the sealing material 88 described above. The hollow recovery portion 86 is arranged along the longitudinal direction of the developing roller 62 in the vicinity of the developing nip portion 74 when the developing device 20Y is attached.

  The hollow recovery part 86 is for introducing an introduction opening 85 for introducing the dust toner into the hollow recovery part 86, and for discharging the airflow introduced into the hollow recovery part 86 so as to guide the air away from the developing nip part 74. An exhaust opening 93 is provided.

  The introduction openings 85 are formed on the side walls that form the recesses 84 at both ends in the longitudinal direction of the hollow recovery portion 86. The exhaust openings 93 are formed at both ends in the longitudinal direction of the seal body 92 of the seal material 88 constituting the upper surface of the hollow recovery portion 86.

  The seal member 88 is configured by attaching a filter 90 to the lower surface of the seal main body 92, and the exhaust opening 93 is closed by the filter 90. The exhaust opening 93 can be ventilated, and the filter 90 prevents passage of the dust toner. The filter 90 may be attached to the entire lower surface of the seal main body 92 or may be partially attached to the lower surface of the seal main body 92 so as to close the exhaust opening 93.

  In the mounted state of the developing device 20Y, the guide member 94 is arranged on the upper side of the recovery member 80, that is, on the opposite side of the development nip 74 with the recovery member 80 interposed therebetween. It contacts the lower surface of the member 94.

  At both ends in the longitudinal direction of the lower surface of the guide member 94, vent openings 95 for allowing the air flow discharged from the hollow recovery portion 86 through the exhaust openings 93 to be provided corresponding to the exhaust openings 93. It has been.

  At the lower end of the guide member 94, there is an airflow introduction damming portion 96 for damming the airflow pushed by the end sealant 100 and pushed away from the developing nip portion 74 and guiding it to the introduction opening 85. The tip of the photosensitive drum 16Y side is provided so as to be close to the photosensitive drum 16Y. As described above, the airflow introducing damming portion 96 is arranged close to the photosensitive drum 16Y with a slight gap therebetween, but the electrostatic latent image on the photosensitive drum 16Y. You may provide so that it may contact with the area | region in which an image is not formed.

  The airflow introducing damming portions 96 are provided at both ends in the longitudinal direction of the guide member 94 corresponding to the introduction openings 85 of the hollow recovery portion 86. The shape of the airflow introducing damming portion 96 is not particularly limited as long as the airflow rising toward the airflow introducing damming portion 96 is guided to the introduction opening 85.

  Next, the airflow around the developing device 20Y generated in accordance with the operation of the image forming apparatus will be described with reference to FIGS. In FIG. 4, for convenience of explanation, the guide member 94 and the developing device 20Y are illustrated in a state where they are separated in the vertical direction.

  When the image forming apparatus is operated, the intermediate transfer belt 4 is rotationally driven, and the lower horizontal portion of the intermediate transfer belt 4 moves to the right in the drawing at a predetermined speed as shown in FIG. Then, an airflow in the right direction in the figure along the moving direction of the intermediate transfer belt 4 is generated below the lower horizontal portion of the intermediate transfer belt 4. The airflow in the right direction passes over the guide member 94, is blocked by the photosensitive drum 16Y, and then descends through the gap between the guide member 94 and the recovery member 80 and the photosensitive drum 16Y. And reaches the vicinity of the lower development nip 74.

  As shown in FIG. 4, the airflow that has reached the vicinity of the developing nip 74 is a flow from the intermediate portion in the longitudinal direction of the developing roller 62 toward both ends, and the airflow that has reached both ends in the longitudinal direction of the developing roller 62 It is blocked by the sealing material 100 and pushed away from the developing nip 74, that is, pushed upward.

  As shown in FIG. 3B, the air flow pushed upward is blocked by the air flow introduction dam 96 of the guide member 94 and guided to the introduction opening 85 of the recovery member 80. The airflow introduced into the hollow collection portion 86 through the introduction opening 85 is discharged through the exhaust opening 93 and guided to the upper side of the guide member 94 through the ventilation opening 95 of the guide member 94.

  In the vicinity of the developing device 20Y, the airflow is always generated while the intermediate transfer belt 4 is driven. Therefore, the dust toner generated in the developing nip portion 74 is introduced into the hollow recovery portion 86 by the airflow. Then, it adheres to the filter 90 constituting the upper wall surface in the hollow recovery part 86 or is accommodated in the hollow recovery part 86 without being attached to the filter 90.

  As described above, the dust toner generated in the development nip 74 is collected by using the airflow generated by the operation of the apparatus, and therefore the toner that originally contributes to the development is sucked as in the case of forced suction. Thus, it is possible to prevent contamination in the apparatus due to the scattering of the dust toner while avoiding the troubles.

  5 and 6 show the developing device 20Y and its peripheral structure in the second embodiment. 5A shows a middle portion in the longitudinal direction of the developing device 20Y, and FIG. 5B shows one end portion in the longitudinal direction of the developing device 20Y. In FIG. 6, for convenience of explanation, the guide member 94 and the developing device 20 </ b> Y are illustrated in a state where they are separated in the vertical direction.

  In the present embodiment, the airflow introduction dam 96 is located on the opposite side of the development nip 74 with respect to the introduction opening 85 in the collection member 80, specifically at the upper end of the side wall constituting the hollow collection portion 86. The front end on the photosensitive drum 16Y side is provided so as to be close to the photosensitive drum 16Y. Airflow introduction damming portions 96 are provided at both ends in the longitudinal direction of the hollow recovery portion 86 corresponding to the introduction opening 85.

  Also in the present embodiment, as in the first embodiment, the airflow that rises away from the development nip portion 74 from both longitudinal ends of the development nip portion 74 is blocked by the airflow introduction damming portion 96. , And led to the introduction opening 85.

  That is, while the intermediate transfer belt 4 is being driven, an air flow similar to that in the first embodiment is always generated, and the dust toner generated in the developing nip portion 74 is guided to the hollow recovery portion 86 by the air flow, and is hollow. It adheres to the filter 90 that constitutes the upper wall surface in the recovery part 86 or is not attached to the filter 90 and is accommodated in the hollow recovery part 86.

  In the second embodiment, other configurations and effects are the same as those of the first embodiment. In FIGS. 5 and 6, members having the same functions as those of the first embodiment are denoted by the same reference numerals. It is.

  7 and 8 show the developing device 20Y and its peripheral structure in the third embodiment. 7A shows the intermediate portion in the longitudinal direction of the developing device 20Y, and FIG. 7B shows one end portion in the longitudinal direction of the developing device 20Y. Further, in FIG. 8, for convenience of explanation, the guide member 94 and the developing device 20Y are illustrated in a state where they are separated in the vertical direction.

  In the present embodiment, the guide member 94 has a duct portion 102 that guides the airflow supplied through the ventilation opening 95. The duct portion 102 includes a groove portion 104 that opens upward and includes a ventilation opening 95 at the bottom, and a cover member 106 that covers the entire upper end opening of the groove portion 104.

  One end in the longitudinal direction of the duct portion 102 is connected to a suction fan (not shown) that sucks air in the duct portion 102. And the speed of the airflow in the duct part 102 can be adjusted now by operating a suction fan.

  In the present embodiment, the airflow generated with the rotational drive of the intermediate transfer belt 4 is introduced into the hollow recovery portion 86 through the same path as in the first and second embodiments, and the exhaust opening 93 and the vent opening. After being supplied from the hollow recovery portion 86 side to the guide member 94 side through 95, as shown in FIG. 8, the inside of the duct portion 102 flows toward the suction fan side.

  Then, by operating the suction fan and adjusting the speed of the airflow in the duct portion 102, the speed of the airflow around the developing nip portion 74 can be adjusted. By appropriately adjusting the speed, the dust toner generated at the development nip 74 can be collected more efficiently, and the increase in the amount of dust toner scattered can be accommodated.

  In the third embodiment, other configurations and effects are the same as those of the first embodiment. In FIGS. 7 and 8, members having the same functions as those of the first embodiment are denoted by the same reference numerals. It is.

1 is a cross-sectional view illustrating an image forming apparatus according to a first embodiment. FIG. 2 is an enlarged cross-sectional view showing an image forming unit in the image forming apparatus shown in FIG. 1. FIG. 3 is a cross-sectional view showing a path of airflow around a developing nip portion in the first embodiment. It is a perspective view which shows the path | route of the airflow shown in FIG. It is sectional drawing which shows the path | route of the air current around the developing nip part in 2nd Embodiment. It is a perspective view which shows the path | route of the airflow shown in FIG. It is sectional drawing which shows the path | route of the airflow around a developing nip part in 3rd Embodiment. It is a perspective view which shows the path | route of the airflow shown in FIG.

Explanation of symbols

2 image forming apparatus body,
4 Intermediate transfer belt,
16Y, 16M, 16C, 16K Image carrier (photosensitive drum),
20Y, 20M, 20C, 20K developing device,
62 developer carrier (developing roller),
74 Development nip,
80 collection member,
85 Introduction opening 86 Hollow recovery part,
90 filters,
93 Exhaust opening,
94 guide members,
95 Ventilation opening,
96 Weir stop for airflow introduction,
100 end damming member (end sealant),
102 Duct section.

Claims (4)

An image forming apparatus comprising: an image carrier that carries an electrostatic latent image; and a developer carrier that is disposed opposite to the image carrier to perform development by attaching toner to the electrostatic latent image.
A collecting member that collects dust toner generated at a developing nip portion between the image carrier and the developer carrier using an air flow generated in accordance with the operation of the image forming apparatus,
A hollow recovery portion provided along the longitudinal direction of the developer carrier near the upper side of the development nip portion;
And because of the introduction opening for introducing the Konakemuri toner to the hollow collecting unit,
An exhaust opening for discharging the air flow introduced into the hollow recovery portion so as to guide upward ,
End damming members for damming the airflow flowing from the longitudinal intermediate portion of the developer carrier toward both ends in the vicinity of the upper side of the developing nip portion are provided at both longitudinal ends of the developing nip portion,
Predetermined position of the member provided on the upper side of the collecting member, or at a position above side than the introduction opening in the collecting member, away from the developing nip portion dammed by stop member dam said end An airflow introduction damming portion for damming the airflow pushed upward and guiding the airflow to the introduction opening is provided so as to protrude so that the tip on the image carrier side is close to or in contact with the image carrier. And
The introduction opening is provided at a portion on both ends in the longitudinal direction of the hollow recovery portion above the development nip portion and facing the image carrier.
The exhaust opening is provided on an upper surface portion at both longitudinal ends of the hollow recovery portion, and is covered with a filter for collecting and collecting the dust toner. Forming equipment. An endless intermediate transfer belt having a horizontal portion at least on the lower side;
Below the horizontal portion, the image carrier and the developer carrier flow along the moving direction of the intermediate transfer belt below the horizontal portion as the intermediate transfer belt rotates. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is arranged so as to be blocked by the image carrier and guided to the developing nip portion below. A developing device having the developer carrying member and the collecting member is guided and detachable by a guide member provided in the image forming apparatus main body, and the upper surface of the hollow collecting portion is mounted in the mounted state of the developing device. Configured to contact the lower surface of the guide member,
The exhaust openings are provided at both longitudinal ends of the upper surface of the hollow recovery part,
Ventilation openings for passing the airflow discharged from the hollow recovery part through the exhaust opening are provided at both ends in the longitudinal direction of the lower surface of the guide member corresponding to the exhaust opening. The image forming apparatus according to claim 2, wherein the image forming apparatus is an image forming apparatus. The guide member has a duct portion for passing the airflow supplied through the ventilation opening, and the duct portion is connected to a suction fan that sucks air in the duct portion. The image forming apparatus according to claim 3 .

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