Image forming apparatus

Abstract

To devise the configuration of a duct in an image forming apparatus to reduce ventilation resistance, thereby improving exhaust efficiency.SOLUTION: An image forming apparatus 1 comprises: a drum unit; a power supply section 70; an exhaust fan 81 that exhausts air inside the apparatus to the outside; and a housing 2 that includes a duct 23 having a first partition wall 231 that partitions a first channel 23A guiding air from the drum unit toward the exhaust fan 81 and a second channel 23B guiding air from the power supply section 70 toward the exhaust fan 81 from each other. The first partition wall 231 is in contact with or proximity to the exhaust fan 81 at one end.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an image forming apparatus.

Background Art

[0002] Conventionally, in an image forming apparatus such as a laser printer, an exhaust fan is provided to discharge heat and ozone generated inside the apparatus to the outside. For example, Patent Document 1 discloses an image forming apparatus including a process unit including a photoreceptor, a fixing unit that thermally fixes toner to a sheet, a power supply unit supplied with electricity from an external power source, a duct where air from the process unit, the fixing unit, and the power supply unit merges, and an exhaust fan that discharges the air in the duct to the outside of the apparatus body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to the configuration of Patent Document 1, air from the power supply unit and the fixing unit flowing from left to right and air from the process unit flowing from front to back merge in the duct. As a result, while the air from the power supply unit and the fixing unit is smoothly exhausted from the exhaust fan, the air from the process unit collides by merging perpendicularly to the flow of the air from the power supply unit and the fixing unit, deteriorating the flow. Thus, the air flowing in different directions collides when merging, causing ventilation resistance and reducing the exhaust efficiency.

[0005] An object of the present invention is to reduce ventilation resistance and improve exhaust efficiency by devising the configuration of a duct in an image forming apparatus.

Means for Solving the Problems

[0006] The image forming apparatus of the present invention includes a housing having a duct that is partitioned by a first partition wall into a first flow path that guides air from a first part toward an exhaust fan, a second flow path that guides air from a second part toward the exhaust fan, and an exhaust fan that discharges air inside the apparatus to the outside. One end of the first partition wall abuts or is close to the exhaust fan.

[0007] According to the above configuration, by dividing the duct into a first flow path and a second flow path by the first partition wall and eliminating the confluence of air in the duct, the air from the first part and the air from the second part can be guided to the exhaust fan without colliding with each other. Therefore, the ventilation resistance in the duct can be reduced and the exhaust efficiency can be improved.

[0008] In the above image forming apparatus, a third part may be provided, and the duct may be partitioned by a second partition wall into a second flow path and a third flow path that guides air from the third part toward the exhaust fan, and one end of the second partition wall abuts or is close to the exhaust fan.

[0009] According to the above configuration, by dividing the duct into a second flow path and a third flow path by the second partition wall and eliminating the confluence of air in the duct, the air from the second part and the air from the third part can be guided to the exhaust fan without colliding with each other. Therefore, the ventilation resistance in the duct can be reduced and the exhaust efficiency can be improved.

[0010] In the above image forming apparatus, the first part may be a process unit having a photoreceptor, the second part may be a power supply unit having a power supply board, and the third part may be a fixing unit having a heating roller.

[0011] According to the above configuration, the air from the process unit, the air from the power supply unit, and the air from the fixing unit can be guided to the exhaust fan without colliding with each other.

[0012] In the above-described image forming apparatus, the housing may have a slit and include a wall portion disposed between the power supply unit and the second flow path.

[0013] According to the above configuration, by disposing a wall portion having a slit, the ventilation amount from the power supply unit to the second flow path can be adjusted.

[0014] In the above-described image forming apparatus, the housing may include a first shielding member that shields the flow of air from the end of the heating roller on the exhaust fan side to the third flow path.

[0015] According to the above configuration, by suppressing the heated air from flowing from the end of the heating roller to the third flow path, it is possible to suppress the temperature of the end of the heating roller on the exhaust fan side from dropping below that of other parts of the heating roller.

[0016] In the above-described image forming apparatus, the housing may include a bearing member that supports the end of the heating roller, and the inner diameter of the first shielding member may be larger than the outer diameter of the bearing member.

[0017] According to the above configuration, even when the bearing member moves due to the linear expansion of the heating roller, it is possible to suppress the bearing member from interfering with the first shielding member.

[0018] In the above-described image forming apparatus, the power supply unit may include a cover having a side surface extending in the vertical direction, and the housing may be fixed to the side surface of the cover and include a second shielding member that shields the fixing unit and the process unit.

[0019] According to the above configuration, it is possible to suppress the air containing water vapor after fixing from flowing from the fixing unit to the process unit.

[0020] In the above-described image forming apparatus, a belt unit that is located upstream in the sheet conveyance direction of the fixing unit and conveys the sheet, and a belt cleaner that is located below the belt unit and cleans the belt unit are provided. The housing may include a first support portion that supports an end portion of the belt unit on the exhaust fan side, and a second support portion that has a space below the first support portion and supports an end portion of the belt cleaner on the exhaust fan side.

[0021] According to the above configuration, by using the space between the first support portion and the second support portion as a part of the exhaust path between the process portion and the first flow path, the exhaust efficiency of the air from the process portion can be improved.

Effects of the Invention

[0022] According to the present invention, by devising the configuration of the duct in the image forming apparatus, the ventilation resistance can be reduced and the exhaust efficiency can be improved.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Modes for Carrying Out the Invention

[0024] In the following description, the right side and the left side in FIG. 2 are defined as the front side and the rear side of the image forming apparatus 1, respectively, and the front side and the rear side of the paper in FIG. 2 are defined as the left side and the right side of the image forming apparatus 1, respectively. Also, the upper side and the lower side in FIG. 2 are defined as the upper side and the lower side of the image forming apparatus 1, respectively. In the present embodiment, the vertical direction is the vertical direction.

[0025] [Overall Configuration of Image Forming Apparatus] FIG. 1 is a perspective view of an image forming apparatus 1 according to an embodiment, and FIG. 2 is a central cross-sectional view of the image forming apparatus 1 of FIG. 1. The appearance of the image forming apparatus 1 is formed by a substantially rectangular parallelepiped housing 2. The housing 2 has a main body frame 20 (see FIG. 4) that supports each member, and a main body cover 21 that covers the main body frame 20 and constitutes the appearance. The main body frame 20 has a left frame 201 (see FIG. 4) disposed on the left side and a right frame 202 (see FIG. 4) disposed on the right side. The main body cover 21 has a discharge tray 211 on the upper surface.

[0026] The image forming apparatus 1 is a color laser printer that forms a multi-color image on a sheet S such as a paper or an OHP sheet by an electrophotographic method. The housing 2 houses a sheet tray 3, a conveyance unit 4, an image forming unit 5, a re-conveyance unit 6, and a control unit 7. Inside the housing 2, roughly speaking, the image forming unit 5 is disposed in the upper part and the central part, the conveyance unit 4 is disposed below and behind the image forming unit 5, the re-conveyance unit 6 extends across the front part and the rear part of the housing 2 and below the conveyance unit 4, and the control unit 7 is disposed between the image forming unit 5 and the re-conveyance unit 6 and on the left and right of the main body frame 20, respectively.

[0027] Also, an opening 22 serving as an insertion port for the sheet tray 3 is formed at the lower part of the front surface of the housing 2. The sheet tray 3 is a box-shaped body having an open upper sheet storage portion 31, and supports a plurality of stacked sheets S. The sheet tray 3 can be inserted into and removed from the housing 2 by moving it back and forth through the opening 22.

[0028] The conveying unit 4 is composed of each member arranged along the conveying path P1, and conveys the sheet S along the conveying path P1. The conveying path P1 is a path that connects from the sheet tray 3 via the image forming unit 5 to the discharge tray 211. The conveying unit 4 is composed of a supply unit 41, a belt unit 42, and a discharge unit 43 in order from the upstream side in the conveying direction of the conveying path P1.

[0029] The supply unit 41 includes a supply roller 411, a separation roller 412, a separation pad 413, a pair of conveying rollers 414, a pair of registration rollers 415, and a support member 416 that supports some rollers of the supply unit 41. The sheet S accommodated in the sheet tray 3 is sent out one by one to the conveying path P1 by the supply roller 411, the separation roller 412, and the separation pad 413. The sheet S sent out to the conveying path P1 is conveyed toward the image forming unit 5 by the pair of conveying rollers 414 and the pair of registration rollers 415.

[0030] The belt unit 42 is detachable from the housing 2, and includes a driving roller 421 that rotates in conjunction with the image forming unit 5, a driven roller 422 rotatably disposed at a position spaced apart from the driving roller 421, and a conveying belt 423 wound between the driving roller 421 and the driven roller 422. Then, when the conveying belt 423 rotates with the sheet S placed thereon, the sheet S is conveyed along the conveying path P1, sent below the drum unit 51 of the image forming unit 5, and then sent to the fixing unit 53.

[0031] The discharge unit 43 includes an intermediate discharge roller pair 431 and a discharge roller pair 432 disposed between the branch portion P11 of the conveying path P1 and the discharge tray 211. The intermediate discharge roller pair 431 and the discharge roller pair 432 are switchback rollers configured to be able to switch the rotation direction between the forward direction and the reverse direction. The intermediate discharge roller pair 431 and the discharge roller pair 432 rotate forward when discharging the sheet S conveyed from the fixing unit 53 onto the discharge tray 211, and rotate reversely when inverting the sheet S and conveying it to the re-conveying path P2.

[0032] In this embodiment, the image forming unit 5 employs an electrophotographic system. Note that other image forming systems such as a thermal system or an inkjet system may be used. The image forming unit 5 is of a so-called direct tandem type capable of color printing, and includes four drum units 51 arranged side by side in the front-rear direction, an exposure LED head 52, a fixing unit 53, and a belt cleaner 54. The drum unit 51 is an example of a process unit.

[0033] Each drum unit 51 is provided corresponding to four colors of toner (developer) of black, yellow, magenta, and cyan. Each drum unit 51 includes a photosensitive drum 511 which is an example of a photoreceptor, a developing roller 512, and transfer rollers 513 arranged at respective positions facing the photosensitive drum 511 with the conveyance belt 423 interposed therebetween.

[0034] In such an image forming unit 5, each photosensitive drum 511 uniformly charged by a charger is selectively exposed by the exposure LED head 52. By this exposure, charges are selectively removed from the surface of each photosensitive drum 511, and an electrostatic latent image is formed on the surface of each photosensitive drum 511.

[0035] A developing bias is applied to each developing roller 512. When the electrostatic latent image formed on each photosensitive drum 511 faces each developing roller 512, toner is supplied from each developing roller 512 to the electrostatic latent image due to the potential difference between the electrostatic latent image and each developing roller 512. Thereby, a toner image is formed on the surface of each photosensitive drum 511.

[0036] The sheet S conveyed toward the image forming unit 5 is conveyed by the conveyance belt 423 and sequentially passes between the conveyance belt 423 and each photosensitive drum 511. Then, when the toner image on the surface of the photosensitive drum 511 faces the sheet S, it is transferred to the sheet S by the transfer bias applied to the transfer roller 513.

[0037] The fixing unit 53 is disposed downstream in the conveyance direction of the four photosensitive drums 511 in the conveyance path P1. The fixing unit 53 includes a heating roller 531 and a pressure roller 532 that is in pressure contact with the heating roller 531. The heating roller 531 is disposed on the image forming surface side of the sheet S, is rotationally driven in synchronization with the conveyance belt 423, and applies a conveyance force to the sheet S while heating the toner.

[0038] On the other hand, the pressure roller 532 is disposed on the side opposite to the heating roller 531 with the sheet S interposed therebetween, and presses the sheet S toward the heating roller 531. As a result, the pressure roller 532 is driven to rotate passively by receiving a rotational force from the heating roller 531 through the sheet S that contacts the heating roller 531.

[0039] Further, the fixing unit 53 includes a fixing discharge roller pair 533 that is disposed downstream in the conveyance direction of the sheet S from the heating roller 531 and the pressure roller 532.

[0040] In the image forming unit 5, the toner image on the sheet S is thermally fixed to the sheet S while passing between the heating roller 531 and the pressure roller 532. The sheet S on which the toner image is thermally fixed is conveyed to the intermediate discharge roller pair 431 while being sandwiched by the fixing discharge roller pair 533.

[0041] The belt cleaner 54 is detachably disposed between the belt unit 42 and the re-conveying unit 6, and is a member for collecting waste toner from the conveyance belt 423.

[0042] The belt cleaner 54 has a backup roller 541, a cleaning roller 542, a recovery roller 543, a scraping blade 544, a recovery chamber 545, and a waste toner box 546.

[0043] The backup roller 541 is disposed inside the conveyance belt 423 and contacts the conveyance belt 423 from above. The cleaning roller 542 is disposed at a position facing the backup roller 541 with the conveyance belt 423 interposed therebetween, and contacts the conveyance belt 423 from below.

[0044] In the belt cleaner 54, waste toner adhering to the conveyor belt 423 is collected by the cleaning roller 542, the recovery roller 543, the scraping blade 544, and the recovery chamber 545, and the collected waste toner is configured to be stored in the waste toner box 546.

[0045] The cleaning operation is started after the completion of the image formation by the image forming unit 5. In the cleaning operation, the waste toner adhering to the surface of the conveyor belt 423 is electrostatically held on the surface of the cleaning roller 542 by the bias applied to the cleaning roller 542, and then electrostatically transferred to the recovery roller 543. The waste toner transferred to the recovery roller 543 is scraped off by the scraping blade 544 and falls into the recovery chamber 545. The waste toner that has fallen into the recovery chamber 545 is conveyed rearward by a conveying means (not shown) and stored in the waste toner box 546.

[0046] The re-conveying unit 6 is composed of each member arranged along the re-conveying path P2, and conveys the sheet S along the re-conveying path P2. The re-conveying path P2 branches from a branch portion P11 between the fixing unit 53 and the intermediate discharge roller pair 431 in the conveying path P1, passes above the sheet tray 3, and merges into a merging portion P12 between the sheet tray 3 and the image forming unit 5. With this configuration, the re-conveying path P2 can be made shorter than a configuration in which the re-conveying path P2 is arranged below the sheet tray 3.

[0047] The re-conveying unit 6 includes a lower chute 61 that guides the lower surface of the sheet S and an upper chute 62 that guides the upper surface of the sheet S, above the sheet tray 3 and below the image forming unit 5. The lower chute 61 includes a skew feed roller pair 611 and a re-conveying roller 612 for guiding the sheet S along the re-conveying path P2. A driven roller 613 that forms a nip with the re-conveying roller 612 is supported by a support member 416 of the supply unit 41 located above the re-conveying roller 612.

[0048] An opening 24 serving as an insertion port for the lower chute 61 is formed in the rear surface of the housing 2. The lower chute 61 can be inserted into and removed from the housing 2 by being moved in the front-rear direction through the opening 24.

[0049] The re-conveying unit 6 conveys the sheet S with an image formed on one surface, which is conveyed from the intermediate discharge roller pair 431, to the confluence portion P12. The sheet S re-conveyed from the confluence portion P12 to the image forming unit 5 has an image formed on the other surface by the image forming unit 5, and then is discharged to the discharge tray 211 by the discharge unit 43. When a jam occurs in the re-conveying unit 6, the jam can be processed by pulling out the lower chute 61.

[0050] As described above, in the image forming apparatus 1, it is possible to perform so-called double-sided printing in which the sheet S with an image formed on one surface by the image forming unit 5 is re-conveyed to the image forming unit 5 through the re-conveying path P2, and an image is formed on the other surface of the sheet S.

[0051] The control unit 7 includes a main circuit board (not shown), a low-voltage circuit board 71 which is an example of a power supply board, a sheet metal member 72 which is an example of a cover, and a high-voltage circuit board (not shown) to which a voltage higher than that of the low-voltage circuit board 71 is applied. The low-voltage circuit board 71 and the sheet metal member 72 constitute the power supply unit 70.

[0052] The main circuit board is disposed on the left surface of the left frame 201, and is a board having a control unit that controls the entire image forming apparatus 1 including the low-voltage circuit board 71 and the high-voltage circuit board. The low-voltage circuit board 71 is disposed behind the belt cleaner 54 and between the re-conveying unit 6 and the image forming unit 5, and is a board to which a low voltage is applied to a power supply circuit or the like.

[0053] The sheet metal member 72 is an enclosure that covers the top, bottom, front, and rear of the low-voltage circuit board 71. The high-voltage circuit board is disposed on the right surface of the right frame 202, and is a board to which a high voltage is applied to the image forming unit 5 or the like.

[0054] Next, in such an image forming apparatus 1, an exhaust structure for exhausting the air inside the housing 2 to the outside for cooling or the like and the surrounding configuration will be described. In particular, a configuration for reducing the ventilation resistance and improving the exhaust efficiency will be described in detail.

[0055] [Exhaust Structure] FIG. 3 is a cross-sectional view taken along line A-A of FIG. 1, FIG. 4 is a perspective view showing the exhaust structure and the main configuration of its periphery, FIG. 5 is a cross-sectional view around the heating roller cover 26, FIG. 6 is a perspective view of the heating roller cover 26, FIG. 7 is a cross-sectional view around the second shielding member 27, FIG. 8 is a perspective view around the first support portion 291 and the second support portion 292, and FIG. 9 is a cross-sectional view around the first support portion 291 and the second support portion 292.

[0056] As shown in FIGS. 3 and 4, the image forming apparatus 1 includes, as an exhaust structure, an exhaust fan 81, an exhaust port portion 212, a duct 23, a wall portion 25, a first shielding member 261 (see FIGS. 5 and 6), and a second shielding member 27 (see FIG. 7). The exhaust port portion 212, the duct 23, the wall portion 25, the first shielding member 261, and the second shielding member 27 are included in the housing 2.

[0057] As shown in FIG. 3, the exhaust fan 81 is attached near the lower rear portion of the right frame 202 and is a fan for discharging the air inside the housing 2 to the outside. The exhaust port portion 212 is formed at a position facing the exhaust fan 81 on the right side surface 21A of the main body cover 21. The exhaust port portion 212 is a substantially rectangular opening formed to be approximately the same size as the exhaust fan 81 and has a louver. The exhaust from the exhaust fan 81 is discharged to the outside through the exhaust port portion 212.

[0058] The duct 23 has a first flow path 23A, a second flow path 23B, and a third flow path 23C in order from the bottom. The first flow path 23A is an exhaust path for guiding the air from the process unit (drum unit 51) as an example of the first part toward the exhaust fan 81. The second flow path 23B is an exhaust path for guiding the air from the power supply unit 70 as an example of the second part toward the exhaust fan 81. The third flow path 23C is an exhaust path for guiding the air from the fixing unit 53 as an example of the third part toward the exhaust fan 81.

[0059] The duct 23 has a first partition wall 231 that partitions the first flow path 23A and the second flow path 23B, and a second partition wall 232 that partitions the second flow path 23B and the third flow path 23C. The first partition wall 231 is a wall extending in the horizontal direction that partitions the first flow path 23A and the second flow path 23B in the vertical direction. The second partition wall 232 is a wall extending in the horizontal direction that partitions the second flow path 23B and the third flow path 23C in the vertical direction. With such first partition wall 231 and second partition wall 232, the inside of the duct 23 is divided into a first flow path 23A, a second flow path 23B, and a third flow path 23C. Therefore, it is possible to prevent the air flowing in the first flow path 23A, the air flowing in the second flow path 23B, and the air flowing in the third flow path 23C from merging inside the duct 23.

[0060] Note that the arrangement of the first flow path 23A, the second flow path 23B, and the third flow path 23C inside the duct 23 is not particularly limited, and for example, they may be arranged side by side in the front-rear direction. In this case, the first partition wall 231 and the second partition wall 232 are walls extending in the vertical direction, respectively.

[0061] The right end 233, which is one end of the first partition wall 231, and the right end 234, which is one end of the second partition wall 232, are each in contact with the exhaust fan 81. Note that the right end 233 and the right end 234 may be configured to be close to the exhaust fan 81. Thus, since the right end 233 of the first partition wall 231 and the 234 of the second partition wall 232 are in contact with or close to the exhaust fan 81, it is possible to prevent the air flowing in the first flow path 23A, the air flowing in the second flow path 23B, and the air flowing in the third flow path 23C from merging between the duct 23 and the exhaust fan 81.

[0062] Therefore, with the duct 23 having the first partition wall 231 and the second partition wall 232, the air from the process unit (drum unit 51), the air from the power supply unit 70, and the air from the fixing unit 53 can be guided to the exhaust fan 81 without colliding with each other. Therefore, the ventilation resistance in the duct 23 can be reduced and the exhaust efficiency can be improved.

[0063] As shown in FIGS. 3 and 4, the wall portion 25 is disposed at the boundary between the power supply unit 70 and the second flow path 23B, and is a member that restricts the ventilation amount from the power supply unit 70 to the second flow path 23B. The wall portion 25 is a plate member that covers the entire left end surface of the second flow path 23B and has a plurality of slits 251. By adjusting the size and number of the slits 251, the ventilation amount from the power supply unit 70 to the second flow path 23B can be adjusted.

[0064] As shown in FIG. 3, the first shielding member 261 is a member that shields the flow of air from the right end portion on the exhaust fan 81 side of the heating roller 531 to the third flow path 23C. The first shielding member 261 in the present embodiment is a part of the heating roller cover 26 as shown in FIGS. 5 and 6. The heating roller cover 26 is a member that covers the lower side of the right end portion of the heating roller 531. The first shielding member 261 is an arc-shaped protruding piece located at the left end of the heating roller cover 26.

[0065] The air heated by the heating roller 531 is suppressed from flowing from the right end portion of the heating roller 531 to the third flow path 23C by the first shielding member 261. As a result, it is suppressed that the temperature of the right end portion on the exhaust fan 81 side of the heating roller 531 becomes lower than other portions of the heating roller 531.

[0066] As shown in FIG. 5, the housing 2 includes an inner bearing member 28 that supports the right end portion of the heating roller 531, and an outer bearing member 282 that rotatably supports the bearing member 281. In the present embodiment, the bearing members 281 and 282 constitute a sliding bearing. And the inner diameter R1 of the first shielding member 261 is formed larger than the outer diameter R2 of the bearing member 281. Thereby, even when the bearing member 28 moves rightward due to the linear expansion of the heating roller 531, it is possible to suppress the bearing member 281 from interfering with the first shielding member 261.

[0067] Further, a clearance between the left end of the first shielding member 261 and the right end of the bearing member 282 forms a labyrinth. Thereby, the heated air inside the heating roller 531 is less likely to leak to the outside of the heating roller 531.

[0068] As shown in FIG. 7, the second shielding member 27 is fixed to the side surface 72A of the sheet metal member 72 extending in the vertical direction, and is a member that shields the fixing portion 53 and the drum unit 51. The second shielding member 27 is a resin film, and the upper end portion is supported in a state of being pressed against the bottom surface of the conveyance guide 91 between the driving roller 421 and the fixing portion 53. Thereby, it is possible to suppress the air containing water vapor after fixing from flowing from the fixing portion 53 to the drum unit 51.

[0069] A registration sensor 92 for detecting a toner test pattern on the conveyance belt 423 is disposed on the driving roller 421 side of the second shielding member 27. The second shielding member 27 also has a role of shielding the fixing portion 53 and the registration sensor 92 and suppressing the air containing water vapor after fixing from flowing from the fixing portion 53 to the registration sensor 92.

[0070] As shown in FIGS. 8 and 9, the housing 2 includes a first support portion 291 and a second support portion 292 in the right frame 202. The first support portion 291 is a member that supports the right end portion, which is the end portion on the exhaust fan 81 side of the belt unit 42. The first support portion 291 is a rail that protrudes leftward from the left surface of the right frame 202 and extends in the front-rear direction. The upper surface of the first support portion 291 guides the right end portion of the belt unit 42 that is detachably attached in the front-rear direction and supports the attached belt unit 42.

[0071] The second support portion 292 is located below the first support portion 291 and has a space B, and is a member that supports the right end portion 54A, which is the end portion on the exhaust fan 81 side of the belt cleaner 54. The second support portion 292 is a hook-shaped member that protrudes leftward from the left surface of the right frame 202. The second support portion 292 positions the right end portion 54A of the belt cleaner 54 that is attached from the upper front and supports the attached belt cleaner 54.

[0072] Space B is the gap between the lower surface 293 at the front end of the first support portion 291 and the upper surface 294 of the second support portion 292. Space B forms part of the exhaust path C between the drum unit 51 and the first flow path 23A. A filter 93 is disposed downstream of space B on the exhaust path C. The filter 93 is a superposition of a filter for trapping dust such as toner and a filter for trapping ozone and volatile organic compounds.

[0073] Thus, by using the space B between the first support portion 291 and the second support portion 292 as part of the exhaust path C between the drum unit 51 and the first flow path 23A, the air exhaust efficiency from the drum unit 51 can be improved compared to a configuration without space B. Note that the front end of the upper surface 294 of the second support portion 292 is located behind the front end of the lower surface 293 of the first support portion 291. This makes it less likely for the right end portion 54A of the belt cleaner 54 mounted from above to get caught on the upper surface 294 of the second support portion 292.

[0074] Note that the image forming apparatus 1 of the above embodiment is configured to include a first part, a second part, and a third part, but it suffices to include at least the first part and the second part. Thereby, by dividing the duct into a first flow path and a second flow path by the first partition wall and eliminating the confluence of air in the duct, the air from the first part and the air from the second part can be guided to the exhaust fan without colliding with each other. Therefore, the ventilation resistance in the duct can be reduced and the exhaust efficiency can be improved.

[0075] Also, in the above embodiment, the first part is the process part, the second part is the power supply part, and the third part is the fixing part, but the configurations of the first part to the third part are not particularly limited, and any configuration that generates air that requires exhaust including heat, ozone, toner, etc. is acceptable.

Explanation of Reference Numerals

[0076] 1 Image forming apparatus 2 Housing 23 Duct 23A First flow path 23B Second flow path 23C Third Flow Path 25 Wall Portion 27 Second Shielding Member 42 Belt Unit 51 Drum Unit (First Part) 53 Fixing Unit (Third Part) 54 Belt Cleaner 70 Power Supply Unit (Second Part) 71 Low-Voltage Circuit Board (Power Supply Board) 72 Sheet Metal Member (Cover) 81 Exhaust Fan 231 First Partition Wall 232 Second Partition Wall 251 Slit 261 First Shielding Member 511 Photosensitive Drum (Photoconductor) 531 Heating Roller 281 Bearing Member 291 First Support Portion 292 Second Support Portion B Space

Claims

1. a first part, a second part, a third part, an exhaust fan for discharging air inside the apparatus to the outside, a housing including a duct having a first partition wall that separates a first flow path for guiding air from the first part toward the exhaust fan and a second flow path for guiding air from the second part toward the exhaust fan, one end of the first partition wall abuts or is close to the exhaust fan, the duct includes a second partition wall that separates the second flow path and a third flow path for guiding air from the third part toward the exhaust fan, and one end of the second partition wall abuts or is close to the exhaust fan, the first part is a process unit having a photoreceptor, the second part is a power supply unit having a power supply board, the third part is a fixing unit having a heating roller, a belt unit that is located upstream in the sheet conveyance direction of the fixing unit and conveys a sheet, a belt cleaner that is located below the belt unit and cleans the belt unit, the housing includes a first support portion that supports an end portion of the belt unit on the exhaust fan side, and a second support portion that is located below the first support portion and has a space and supports an end portion of the belt cleaner on the exhaust fan side. The image forming apparatus is characterized by this.

2. The housing has a slit and includes a wall portion disposed between the power supply unit and the second flow path. The image forming apparatus according to claim 1 is characterized by this.

3. The housing includes a first shielding member that shields the flow of air from an end portion of the heating roller on the exhaust fan side to the third flow path. The image forming apparatus according to claim 1 is characterized by this.

4. The housing includes a bearing member that supports the end portion of the heating roller, and the inner diameter of the first shielding member is larger than the outer diameter of the bearing member. The image forming apparatus according to claim 3 is characterized by this.

5. The power supply unit includes a cover having a side surface extending in the vertical direction, and the housing includes a second shielding member that is fixed to the side surface of the cover and shields the fixing unit and the process unit. The image forming apparatus according to claim 1 is characterized by this.

Images