Image forming apparatus

Abstract

The present invention provides an image forming apparatus that can place an exhaust filter between the fan and the housing while suppressing an increase in the size of the apparatus. [Solution] The image forming apparatus 1 comprises a housing 2 having a right side wall 23 having an exhaust port 23a, a fan 71 for exhausting air from inside the housing 2, and an exhaust filter 72 disposed between the right side wall 23 and the fan 71. The right side wall 23 has a first rib 231 that abuts against a first end face 722a of the circumferential end faces 722 located on the outer circumference of the exhaust filter 72, and a pressing body 73 that presses against a second end face 722b of the circumferential end faces 722a, which is different from the first end face 722a, so that the first end face 722a and the first rib 231 are in contact.

Description

Technical Field

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

[0002] Conventionally, there has been known an image forming apparatus including a housing having an exhaust port, a fan that exhausts air inside the housing, and an exhaust filter disposed between the fan and the housing, wherein the exhaust filter is held by the housing.

[0003] For example, in the image forming apparatus disclosed in Patent Document 1, the exhaust filter disposed opposite the exhaust port of the housing is pressed from the inner side of the housing by a duct that accommodates the fan, and is pressed against the side wall of the housing, thereby holding the exhaust filter. Prior Art Literature Patent Literature

[0004] Patent Document 1 Japanese Unexamined Patent Application Publication No. 2024-28107 Summary of the Invention Problem to be Solved by the Invention

[0005] As described above, in the configuration where the exhaust filter is pressed against the side wall from the inner side of the housing, it is not preferable to press the filter directly by the rotating fan. Therefore, it is necessary to extend the duct from the fan toward the exhaust filter side, and press the exhaust filter with the duct in a state where a gap is formed between the exhaust filter and the fan, or dispose a separate component for pressing the exhaust filter between the exhaust filter and the fan.

[0006] As described above, extending the duct toward the exhaust filter side or disposing a separate component between the exhaust filter and the fan causes a problem such as an increase in size of the apparatus.

[0007] Therefore, the present invention provides an image forming apparatus that can arrange an exhaust filter between the fan and the housing while suppressing an increase in the size of the apparatus. [Means for solving the problem]

[0008] The image forming apparatus that solves the above problems has the following features.

[0009] That is, the image forming apparatus comprises a housing having a side wall with an exhaust port, a fan for exhausting air from inside the housing, and an exhaust filter disposed between the side wall and the fan, wherein the side wall has a contact portion that abuts against a first end face of the circumferential end face located on the outer circumference of the exhaust filter, and a pressing portion that presses against a second end face of the circumferential end face, which is different from the first end face, so that the first end face and the contact portion are in pressure contact.

[0010] This configuration allows the exhaust filter to be held in place by the contact and pressing portions on the side wall of the housing, compressing it in a direction along the side wall. Therefore, it is possible to hold the exhaust filter without placing any parts to press the exhaust filter between the exhaust filter and the fan, or extending the duct supporting the fan toward the exhaust filter. This allows the exhaust filter to be placed between the fan and the side wall of the housing while suppressing an increase in the size of the image forming apparatus.

[0011] Furthermore, the side wall has a protruding wall that projects toward the interior side of the housing, and the pressing portion is an elastic body positioned between the protruding wall and the second end face of the exhaust filter.

[0012] In this way, by positioning the elastic body, which acts as a pressing part, between the protruding wall of the side wall and the second end face of the exhaust filter, the exhaust filter can be stably pressed.

[0013] Furthermore, the pressing portion is made of sponge, and the housing is further formed of a metal member and has a spring that is electrically connected to a conductive component placed inside the housing, and which contacts the second end face of the exhaust filter to generate a pressing force that presses in the same direction as the sponge.

[0014] In this way, by bringing the spring into contact with the exhaust filter, the exhaust filter can be grounded. Furthermore, by pressing the second end face of the exhaust filter with the spring, the first end face of the exhaust filter can be stably pressed against the contact point.

[0015] Furthermore, the exhaust filter has a permeable surface that faces the side wall and through which exhausted air passes, and the side wall has a first louver positioned at the exhaust port and restricting the direction of air exhaust, and a first rib as a contact portion that protrudes toward the inside of the housing, the first rib located above the exhaust filter and in contact with the first end face of the exhaust filter, a second rib that protrudes toward the inside of the housing and is located below the exhaust filter, a liquid outlet located below the second rib that discharges liquid flowing along the second rib to the outside of the housing, and a first positioning rib that protrudes toward the inside of the housing and in contact with the permeable surface of the exhaust filter, positioning the exhaust filter at a position away from the first louver, the second rib guides the exhaust filter attached to the side wall to the mounting position on the side wall and guides the liquid to the liquid outlet.

[0016] This allows the second rib, which guides the liquid to the liquid outlet, to also serve as a guide when attaching the exhaust filter to the side wall. Furthermore, it prevents liquid that has entered the interior of the housing through the first louver from coming into contact with the exhaust filter.

[0017] Furthermore, the second rib includes a non-contact rib that does not come into contact with the exhaust filter attached to the side wall, and a contact rib that intersects the vertical direction and is positioned differently from the non-contact rib in a direction along the side wall, and comes into contact with the exhaust filter attached to the side wall.

[0018] This allows the exhaust filter, which is mounted on the side wall, to be guided while preventing the liquid flowing along the second rib from coming into contact with the exhaust filter.

[0019] Furthermore, the side wall includes a second louver positioned at the exhaust port to restrict the direction of air exhaust, the second louver being movable so as to change the direction of air exhaust, and a second positioning rib that protrudes further inward from the second louver than the second louver and contacts the exhaust filter positioned at a distance from the second louver.

[0020] This prevents the moving second louver from coming into contact with the exhaust filter, thus suppressing damage to the exhaust filter.

[0021] The system further comprises a frame that supports the fan, and the frame has a fan pressing portion that presses the fan such that the direction in which the fan presses against the frame is the same direction in which the pressing portion presses against the exhaust filter.

[0022] This allows for precise alignment between the exhaust filter, which is held on the side wall of the enclosure, and the fan, which is held on the frame side.

[0023] Furthermore, the fan has a vent through which the exhaust air passes, and the exhaust filter is sized to cover the vent of the fan and not to protrude from the outer shape of the fan when viewed from the direction through which the vent passes.

[0024] This prevents the exhaust filter from becoming unnecessarily large, thus reducing costs.

[0025] Further, the housing accommodates an image forming unit that forms an image on a sheet, the image forming unit includes a drum that forms a toner image on a sheet, a charger that charges the drum, and a fixing device that fixes the toner image formed on the sheet, and the filter is an ozone filter capable of removing ozone from passing air.

[0026] This can suppress ozone generated inside the housing from leaking out of the housing.

[0027] The present invention further comprises an image forming unit capable of printing an image on a sheet, a control unit that controls driving of the fan, and a sensor that detects an environmental temperature, wherein the fan can be driven at a first rotation speed and a second rotation speed slower than the first rotation speed, and the control unit drives the fan at the first rotation speed when the environmental temperature detected by the sensor exceeds a first environmental temperature, the image forming unit performs single-sided printing on a sheet, and drives the fan at the second rotation speed when the environmental temperature detected by the sensor is equal to or lower than the first environmental temperature.

[0028] As described above, under conditions where the temperature inside the housing does not rise significantly, the amount of ozone removed by the exhaust filter can be increased by reducing the speed at which ozone-containing air passes through the exhaust filter.

[0029] Further, the sensor is capable of detecting environmental humidity, and the control unit drives the fan at the first rotation speed when the environmental temperature detected by the sensor is equal to or lower than a second environmental temperature which is lower than the first environmental temperature, and the environmental humidity detected by the sensor is equal to or higher than a first environmental humidity.

[0030] In low-temperature, high-humidity environments, such as when the ambient temperature is below the second ambient temperature and the ambient humidity is above the first ambient humidity, a sheet containing a large amount of moisture is heated by the fuser, causing moisture to be released from the sheet, which may lead to condensation inside the enclosure. In such conditions where condensation may occur inside the enclosure, driving the fan at full speed to increase the exhaust volume by the fan can quickly expel the moisture inside the enclosure and suppress the occurrence of condensation.

[0031] Furthermore, the control unit drives the fan for a predetermined time after the image forming unit has finished printing on the sheet.

[0032] If the exhaust fan is stopped immediately after printing on the sheet is complete, ozone-containing air will remain inside the enclosure and may leak out through gaps in the enclosure. Therefore, by running the fan for a predetermined time after printing is complete, the ozone-containing air inside the enclosure can be exhausted after the ozone has been removed by the exhaust filter, thus preventing ozone-containing air from leaking out through gaps in the enclosure. [Effects of the Invention]

[0033] According to the present invention, an exhaust filter can be placed between the fan and the side wall of the housing while suppressing an increase in the size of the image forming apparatus. [Brief explanation of the drawing]

[0034] [Figure 1] This is a schematic central cross-sectional view showing an image forming apparatus. [Figure 2] This is a perspective view showing an image forming apparatus. [Figure 3] This is a plan cross-sectional view showing the right side wall, exhaust filter, fan, and right frame. [Figure 4] This is a side view of the right side wall, exhaust filter, and fan, seen from the inside of the enclosure. [Figure 5] This is a side view showing the louvers on the right wall. [Figure 6] This is a perspective view showing the exhaust filter. [Figure 7] This is a side view from the inside of the enclosure, showing the section of the right wall where the louvers are formed. [Figure 8] This is a perspective view from the inside of the enclosure of the section of the right wall where the louvers are formed. [Figure 9] This is a perspective view from the inside of the enclosure of the section of the right wall where the louvers are formed. [Figure 10] This is a side view of the exhaust filter, supported on the right wall, as seen from inside the enclosure. [Figure 11] This is a perspective view of the exhaust filter, supported on the right side wall, as seen from the inside of the enclosure. [Figure 12] This is a side view showing the right frame and exhaust filter. [Figure 13] This is a perspective view showing a spring. [Figure 14] This is a block diagram showing the fan and each sensor connected to the control unit. [Figure 15] This diagram shows the fan operating conditions. [Figure 16] This diagram shows the fan operation status in continuous printing mode and intermittent printing mode. [Figure 17] This is a perspective view showing an image forming apparatus according to the second embodiment. [Figure 18] This is a front cross-sectional view showing the right side wall, exhaust filter, and fan of an image forming apparatus according to the second embodiment. [Figure 19] This is a side view showing a fan fitted into a duct in an image forming apparatus according to the second embodiment. [Figure 20] This is a side view showing the louvers of an image forming apparatus according to the second embodiment. [Figure 21] This is a side view of the exhaust filter supported on the right side wall of the image forming apparatus according to the second embodiment, as seen from the inside of the housing. [Figure 22] This is a perspective view showing the exhaust filter in the image forming apparatus according to the second embodiment. [Figure 23]This is a side view of the portion of the right side wall where the louvers are formed in the image forming apparatus according to the second embodiment, as seen from the inside of the housing. [Figure 24] This is a perspective view from the inside of the housing of the portion of the right wall where the louvers are formed in the image forming apparatus according to the second embodiment. [Figure 25] This is a side view of the exhaust filter supported on the right side wall of the image forming apparatus according to the second embodiment, as seen from the inside of the housing. [Modes for carrying out the invention]

[0035] Next, embodiments for carrying out the present invention will be described with reference to the attached drawings.

[0036] [Image forming apparatus] The image forming apparatus 1 shown in Figure 1 is one embodiment of the image forming apparatus according to the present invention, and is a laser printer that forms an image on a sheet S using an electrophotographic method.

[0037] In the following explanation, the right side of Figure 1 is defined as the front side of the image forming apparatus 1, the left side of Figure 1 is defined as the rear side of the image forming apparatus 1, the front of the page in Figure 1 is defined as the left side of the image forming apparatus 1, and the back of the page in Figure 1 is defined as the right side of the image forming apparatus 1. Furthermore, the top and bottom sides of Figure 1 are defined as the top and bottom sides of the image forming apparatus 1, respectively.

[0038] The image forming apparatus 1 comprises a housing 2, a paper feeding unit 3, an image forming unit 5, a fuser 6, and a paper discharge unit 29.

[0039] The housing 2 houses the paper feeding unit 3, the image forming unit 5, the fuser unit 6, and the paper discharge unit 29. An opening 20 is located on the front of the housing 2, and the housing 2 has a front cover 21 that can open and close the opening 20. The front cover 21 is configured to rotate around a pivot axis 21a at its lower end, and by rotating around the pivot axis 21a, it can move between a closed position that closes the opening 20 and an open position that opens the opening 20.

[0040] The paper feeding unit 3 comprises a paper feeding tray 10 that supports the sheet S, a sheet transport unit 30, a transport roller pair 34, and a registration roller 35a. The paper feeding unit 3 is located at the bottom of the housing 2 and transports the sheet S supported by the paper feeding tray 10 to the image forming unit 5. The image forming apparatus 1 has a transport path P1 for the sheet S from the paper feeding unit 3 through the image forming unit 5 to the paper discharge unit 29.

[0041] The paper feed tray 10 has a pressure plate 12 and a pressing plate 13. The pressure plate 12 is a plate-shaped member that supports the sheet S from below. The pressure plate 12 is rotatable about a pivot point 12a at its rear end, and by rotating about the pivot point 12a, it can move up and down between a lowered position and an elevated position. The pressing plate 13 is located below the pressure plate 12 and can move the pressure plate 12 up and down between a lowered position and an elevated position.

[0042] The sheet transport unit 30 is a transport mechanism that separates and removes sheets S supported by the paper feed tray 10 one by one and transports them toward the image forming unit 5, and is equipped with a paper feed roller 31, a separation roller 32, and a separation pad 33.

[0043] The paper feed roller 31 is a roller for feeding the sheet S, supported by the paper feed tray 10, toward the separation roller 32. The separation roller 32 is located downstream of the paper feed roller 31 in the sheet transport direction, and the separation pad 33 is positioned opposite the separation roller 32 and is biased toward the separation roller 32.

[0044] The sheets S, fed towards the separation roller 32 by the paper feed roller 31, are separated one by one between the separation roller 32 and the separation pad 33. The separated sheets S are then fed into the transport path P1.

[0045] The sheet S, which has been sent onto the transport path P1, is transported toward the image forming unit 5 by the transport roller pair 34, the register roller 35a, and the pinch roller 35b positioned opposite the register roller 35a. The register roller 35a restricts the movement of the leading edge of the sheet S being transported from the paper feed tray 10 toward the image forming unit 5, stopping it temporarily, correcting the tilt of the sheet S, and then transporting the sheet S toward the image forming unit 5 at a predetermined timing. The register roller 35a is a roller for correcting the tilt of the sheet S being transported toward the image forming unit 5.

[0046] The image forming unit 5 is located downstream of the paper feeding unit 3 in the sheet transport direction and forms an image on the sheet S transported from the paper feeding unit 3. In other words, the image forming unit 5 is capable of printing an image on the sheet S. The image forming unit 5 includes a process cartridge 50 that transfers a toner image to the surface of the sheet S transported from the paper feeding unit 3, a transfer roller 55 positioned opposite the photosensitive drum 54 of the process cartridge 50, and an exposure unit 56 that exposes the surface of the photosensitive drum 54.

[0047] The process cartridge 50 is located above the paper feed section 3 in the housing 2 and includes a toner storage chamber 51, a supply roller 52, a developing roller 53, a photosensitive drum 54, a charger 57, and the like. The process cartridge 50 supports the pinch roller 35b.

[0048] The process cartridge 50 comprises a drum cartridge having a photosensitive drum 54 and a developing cartridge mounted on the drum cartridge and having a developing roller 53, and is detachably mounted on the housing 2. In this case, the process cartridge 50 is mounted on the housing 2 by inserting the drum cartridge and the developing cartridge mounted on the drum cartridge into the housing 2 as a single unit, and is detached from the housing 2 by removing the drum cartridge and the developing cartridge mounted on the drum cartridge from the housing 2 as a single unit.

[0049] The process cartridge 50 may consist of at least one of a photosensitive drum, a developing roller, and a toner container. The process cartridge 50 can be attached to and detached from the housing 2 when the front cover 21 is in the open position.

[0050] The photosensitive drum 54 is positioned with its axis aligned in the left-right direction when the process cartridge 50 is mounted in the housing 2. The photosensitive drum 54 has a metal drum shaft 54a that extends along the axial direction. The photosensitive drum 54 rotates about the drum shaft 54a.

[0051] In this embodiment, the process cartridge 50 comprises a drum cartridge having a photosensitive drum 54 and a developing cartridge mounted on the drum cartridge and having a developing roller 53. However, it can also be configured to include a cartridge having the photosensitive drum 54 and the developing roller 53, and a toner box mounted on the cartridge for containing toner.

[0052] Furthermore, in the image forming apparatus 1, a drum cartridge having a photosensitive drum 54 and a developing cartridge having a developing roller 53 can be configured to be mounted separately in the housing 2. That is, the process cartridge 50 can include at least one of a photosensitive drum, a developing roller, and a toner container, and can be configured to be detachably mounted in the main body of the apparatus.

[0053] The exposure unit 56 is equipped with a laser diode, a polygon mirror, a lens, and a reflector, and exposes the surface of the photosensitive drum 54 by irradiating the photosensitive drum 54 with laser light based on image data input to the image forming apparatus 1.

[0054] The toner storage chamber 51 contains toner, which is used as a developer. The toner stored in the toner storage chamber 51 is agitated by an agitator (not shown) and sent to the supply roller 52. The supply roller 52 then supplies the toner sent from the toner storage chamber 51 to the developer roller 53.

[0055] The developing roller 53 is positioned in close contact with the supply roller 52 and carries positively charged toner supplied from the supply roller 52 by a sliding contact member (not shown). A developing bias is also applied to the developing roller 53 by a bias application means (not shown).

[0056] The photosensitive drum 54 is positioned adjacent to the developing roller 53. The surface of the photosensitive drum 54 is uniformly charged by the charger 57 and then exposed by the exposure unit 56. The exposed portion of the photosensitive drum 54 has a lower potential than other portions, and an electrostatic latent image based on the image data is formed on the photosensitive drum 54. Then, positively charged toner is supplied from the developing roller 53 to the surface of the photosensitive drum 54 where the electrostatic latent image has been formed, causing the electrostatic latent image to become visible as a toner image.

[0057] The transfer roller 55 is positioned opposite the photosensitive drum 54, and a transfer bias is applied by a bias application means (not shown). With the transfer bias applied to the surface of the transfer roller 55, the sheet S is transported while being sandwiched between the photosensitive drum 54, on which the toner image has been formed, and the transfer roller 55, thereby transferring the toner image formed on the surface of the photosensitive drum 54 to the surface of the sheet S. In this way, a toner image is formed on the sheet S by the photosensitive drum 54. The photosensitive drum 54 is an example of a drum that forms a toner image on a sheet. The sheet S on which the toner image has been transferred is transported to the fuser 6.

[0058] The fuser unit 6 comprises a heating unit 61 and a pressure roller 62, and fixes the toner image formed on the sheet S. The heating unit 61 is heated by power supplied from a power source (not shown). The pressure roller 62 is positioned opposite the heating unit 61. One of the heating unit 61 and the pressure roller 62 is biased toward the other by a biasing mechanism (not shown), and the heating unit 61 and the pressure roller 62 are in close contact. The image forming apparatus 1 is equipped with a motor 4, and the pressure roller 62 of the fuser unit 6 is driven to rotate by the driving force from the motor 4. The motor 4 is configured to rotate in both forward and reverse directions.

[0059] When the sheet S on which the toner image has been transferred is transported to the fuser 6, the sheet S is heated while being held between the heating unit 61 and the pressure roller 62, thereby fixing the toner image to the sheet S. In this way, the fuser 6 fixes the toner image formed on the sheet S. The sheet S on which the toner image has been fixed by the fuser 6 is transported to the paper discharge section 29 by a pair of post-fixing transport rollers 63 located downstream in the sheet transport direction of the fuser 6.

[0060] The paper discharge unit 29 is located downstream of the fixed-post transport roller pair 63 in the sheet transport direction, and discharges the sheet S, on which an image has been formed in the image forming unit 5, to the outside of the image forming apparatus 1, or transports the sheet S back towards the image forming unit 5.

[0061] The paper output unit 29 includes an output roller 291a, a driven roller 291b positioned opposite the output roller 291a, and an output tray 292. The output tray 292 is provided on the top cover 22 of the housing 2. Printed sheets S, on which toner images have been formed in the image forming unit 5, are output to the output tray 292.

[0062] Of the transport path P1, the transport path P1 downstream of the fuser 6 is formed as the discharge path P1a. The discharge roller 291a is configured to discharge the sheets S that have been transported from the fuser 6 along the discharge path P1a toward the outside of the housing 2. The discharge path P1a is a path that guides the printed sheets S to the discharge tray 292. The discharge tray 292 supports the sheets S that have been discharged to the outside of the housing 2 by the discharge roller 291a.

[0063] The discharge roller 291a is driven by the driving force from the motor 4 and is configured to rotate in both forward and reverse directions. The discharge roller 291a rotates in the forward direction when driven by the driving force from the forward-rotating motor 4, and rotates in the reverse direction when driven by the reverse-rotating motor 4.

[0064] The discharge roller 291a rotates in the forward direction when transporting the sheet S toward the discharge tray 292. In other words, when the discharge roller 291a rotates in the forward direction, it discharges the sheet S transported from the fuser 6 to the outside of the housing 2.

[0065] The image forming apparatus 1 has a re-transport path P2 that guides the single-sided printed sheet S, which has been transported along the transport path P1 and passed through the fuser 6, to the transport path P1 upstream of the register roller 35a in the sheet transport direction.

[0066] The re-transport path P2 branches off from the discharge path P1a at branching point Pb, which is located between the fixed transport roller pair 63 and the discharge roller 291a. It then extends forward between the image forming unit 5 and the paper feed tray 10, and merges with the transport path P1 at merging point Pa, which is located between the transport roller pair 34 and the registration roller 35a.

[0067] The sheet S, which has been transported from the fuser 6 to the paper discharge section 29, can be transported again to the image forming section 5 via the re-transport path P2 by reversing the rotation of the discharge roller 291a. In other words, when the discharge roller 291a rotates in reverse, it guides the sheet S to the re-transport path P2.

[0068] The sheet S, which has been transported to the re-transport path P2 by the discharge roller 291a, is transported toward the image forming unit 5 by a first re-transport roller pair 36 and a second re-transport roller pair 37 provided on the re-transport path P2. The first re-transport roller pair 36 and the second re-transport roller pair 37 are examples of re-transport rollers.

[0069] The sheet S, transported along the re-transport path P2, is transported to the image forming unit 5 after passing the confluence point Pa. In this case, after the leading edge of the sheet S transported along the re-transport path P2 enters the transport path P1 from the confluence point Pa, the motor 4, which is rotating in the reverse direction, is switched to forward rotation to drive the register roller 35a, and the register roller 35a transports the sheet S to the image forming unit 5.

[0070] Thus, the re-transport path P2 is a transport path that transports the sheet S transported from the fuser 6 back towards the image forming unit 5. The first re-transport roller pair 36 and the second re-transport roller pair 37 transport the sheet S back towards the image forming unit 5 along the re-transport path P2 when the motor 4 is rotating in the forward direction. Also, the first re-transport roller pair 36 and the second re-transport roller pair 37 transport the sheet S back towards the image forming unit 5 along the re-transport path P2 when the motor 4 is rotating in the reverse direction.

[0071] The image forming apparatus 1 is capable of single-sided printing by forming a toner image on one side of the sheet S in the image forming unit 5 and then discharging the sheet S to the outside of the housing 2. The image forming apparatus 1 is also capable of double-sided printing by transporting the sheet S, on which a toner image has been formed in the image forming unit 5, back to the image forming unit 5 via the retransport path P2, forming a toner image on the other side of the sheet S, and then discharging the sheet S to the outside of the housing 2.

[0072] The image forming apparatus 1 is equipped with a fan 71 that exhausts the air inside the housing 2 to the outside of the housing 2. The fan 71 is located to the right of the image forming unit 5 inside the housing 2.

[0073] As shown in Figure 2, the right frame 26 is housed at the right end of the housing 2, and the housing 2 has a right side wall 23 that covers the right side of the right frame 26. The right side wall 23 is an example of a side wall provided by the housing. The right side wall 23 is located downstream of the fan 71 in the exhaust direction by the fan 71. The right side wall 23 has an exhaust port 23a that penetrates the right side wall 23 in the left-right direction. The right side wall 23 is an example of a side wall having an exhaust port.

[0074] Fan 71 is supported by the right frame 26 and is positioned so as to overlap with the exhaust port 23a when viewed from the left or right. When fan 71 is driven, an airflow is generated from left to right, and the airflow created by fan 71 exhausts the air inside the housing 2 to the outside of the housing 2 through the exhaust port 23a.

[0075] [fan] As shown in Figures 3 and 12, the right frame 26 has a duct 27 that penetrates in the left-right direction. The fan 71 is fitted into the duct 27. The fan 71 is supported by the right frame 26 by being fitted into the duct 27.

[0076] As shown in Figures 3 and 4, the fan 71 has a rotating shaft 711 extending in the left-right direction, blades 712 fixed to the rotating shaft 711, and a case 713 that rotatably supports the rotating shaft 711, and is an axial flow fan that sends out air along the axial direction of the rotating shaft 711.

[0077] The outer shape of the case 713 in the first fan 71 is rectangular. The outer shape of the case 713 forms the outer shape of the fan 71. The case 713 has a circular vent 713a that penetrates in the left-right direction, and the blades 712 are located within the area enclosed by the vent 713a. Air exhausted by the fan 71 passes through the vent 713a.

[0078] [Luva] As shown in Figures 3 and 5, the right side wall 23 of the housing 2 has a louver 24 positioned at the exhaust port 23a. The louver 24 is an example of a first louver. The louver 24 is located to the right of the fan 71. The louver 24 protrudes to the right from the right side wall 23.

[0079] The louvers 24 connect the inside and outside of the housing 2 and restrict the direction of exhaust air through the exhaust port 23a. In this embodiment, the direction of exhaust air that is exhausted from left to right through the exhaust port 23a is restricted by the louvers 24 to diagonally upward to the right.

[0080] The louver 24 formed on the right side wall 23 is rectangular in shape along the periphery of the exhaust port 23a and has a frame 240 that protrudes to the right from the outer surface of the right side wall 23, and a plurality of vanes 241 arranged within the area enclosed by the frame 240. Multiple vanes 241 are arranged along the vertical and horizontal directions. The vanes 241 are inclined upward from left to right, and the air exhausted from left to right is converted to an upward-right direction as it passes through the louver 24.

[0081] In this embodiment, the louver 24 is formed by integral molding with the right side wall 23, but the louver 24 may also be configured to be detachably attached to the right side wall 23.

[0082] [Exhaust filter] As shown in Figures 3 and 4, the image forming apparatus 1 is equipped with an exhaust filter 72 located between the right side wall 23 and the fan 71 in the left-right direction. The exhaust filter 72 is positioned so as to overlap with the louvers 24 formed on the right side wall 23 when viewed from the left-right direction. The exhaust filter 72 is supported by the right side wall 23.

[0083] The exhaust filter 72 is composed of a honeycomb filter, for example, in which the filter material is formed in a honeycomb shape. As the filter material constituting the exhaust filter 72, for example, paper supported with an ozone decomposition catalyst such as manganese dioxide or activated carbon, a metal such as aluminum, or ceramics can be used. In this embodiment, the exhaust filter 72 is conductive.

[0084] As shown in Figure 6, the exhaust filter 72 is formed in a sheet shape. The exhaust filter 72 has a permeable surface 721 through which exhaust air passes, and a peripheral end surface 722 that is perpendicular to the permeable surface 721 and located on the outer circumference of the exhaust filter 72. The permeable surface 721 is wider than the peripheral end surface 722. The exhaust filter 72 is positioned so that the permeable surface 721 faces the right side wall 23.

[0085] As shown in Figures 6 and 10, the peripheral end surface 722 has a first end surface 722a, a second end surface 722b, and a third end surface 722c. The first end surface 722a is located at the front upper part of the exhaust filter 72 and is an inclined surface that slopes downward as it extends forward. The second end surface 722b is located at the rear lower part of the exhaust filter 72 and is an inclined surface that slopes downward as it extends forward.

[0086] The third end face 722c is located at the front lower part of the exhaust filter 72 and is an inclined surface that slopes downward as it approaches the rear. The first end face 722a and the second end face 722b are parallel surfaces to each other. The third end face 722c is a surface that intersects with the first end face 722a and the second end face 722b.

[0087] As shown in Figure 4, the exhaust filter 72 is sized to cover the vent 713a of the fan 71. The exhaust filter 72 is sized to be the same size as the outer dimensions of the case 713. The exhaust filter 72 can be sized so that it does not protrude from the outer dimensions of the case 713 when viewed from the left-right direction, which is the direction in which the vent 713a penetrates.

[0088] In this way, the exhaust filter 72 can be formed to cover the vent 713a of the fan 71 and to be sized so that it does not protrude from the outer shape of the fan 71 when viewed from the left and right directions, which are the directions in which the vent 713a penetrates. By configuring it in this way, the exhaust filter 72 does not become unnecessarily large, and it is possible to reduce costs.

[0089] Within the housing 2, ozone is generated by components that generate discharges into the atmosphere, such as the charger 57 of the process cartridge 50. Also, within the housing 2, the toner contained in the process cartridge 50 may float.

[0090] The air inside the housing 2 is drawn in by the fan 71, passes through the exhaust filter 72 to remove ozone and dust such as toner, and is then exhausted to the outside of the housing 2 through the louvers 24. Therefore, the amount of ozone and dust contained in the air inside the housing 2 that is exhausted by the fan 71 can be reduced.

[0091] The exhaust filter 72 only needs to be a filter capable of removing at least toner and other dust particles from the air it passes through. Alternatively, the exhaust filter 72 can be an ozone filter capable of removing ozone in addition to toner and other dust particles from the air it passes through.

[0092] By using an ozone filter as the exhaust filter 72, which is capable of removing ozone from the air exhausted by the fan 71, it is possible to reduce the amount of ozone contained in the exhaust from the fan 71. This prevents ozone generated inside the enclosure 2 from leaking out to the outside of the enclosure 2.

[0093] [Right side wall] As shown in Figures 7 to 9, the right side wall 23 has a first rib 231, a second rib 232, and a third rib 233 that protrude toward the inside of the housing 2, and a liquid outlet 23b.

[0094] The first rib 231 is located in front of and above the louver 24 on the right side wall 23 and protrudes to the left from the louver 24. The first rib 231 extends along the right side wall 23 and slopes downward as it extends forward.

[0095] The second rib 232 is located below the first rib 231 and protrudes to the left from the louver 24. The second rib 232 has a non-contact rib 232A and a contact rib 232B.

[0096] The non-contact rib 232A is located at the rear lower part of the louver 24 on the right side wall 23. The non-contact rib 232A extends along the right side wall 23 and slopes downward as it extends forward. The non-contact rib 232A is an example of a protruding wall that projects inward toward the interior of the housing.

[0097] The non-contact rib 232A has a first portion 232Aa and a second portion 232Ab. The second portion 232Ab is located below the first portion 232Aa. The first portion 232Aa and the second portion 232Ab are formed continuously, and the second portion 232Ab extends forward and downward from the lower end of the first portion 232Aa. The amount of leftward projection of the first portion 232Aa is greater than the amount of leftward projection of the second portion 232Ab.

[0098] The contact rib 232B is located in the front lower part of the louver 24 on the right side wall 23. The contact rib 232B extends along the right side wall 23 and slopes downward as it approaches the rear. The contact rib 232B is located in front of the non-contact rib 232A. In other words, the contact rib 232B is positioned differently from the non-contact rib 232A in the direction that intersects the vertical direction and is along the right side wall 23.

[0099] The contact rib 232B has a first part 232Ba and a second part 232Bb. The second part 232Bb is located below the first part 232Ba. The first part 232Ba and the second part 232Bb are formed continuously, and the second part 232Bb extends downward and rearward from the lower end of the first part 232Ba. The amount of leftward projection of the first part 232Ba is greater than the amount of leftward projection of the second part 232Bb.

[0100] The liquid outlet 23b is located at the lower end of the louver 24 and communicates with it in the left-right direction. The liquid outlet 23b is located below the second rib 232. For example, liquid that enters the inside of the housing 2 from the outside of the housing 2 through the louver 24 flows downward along the non-contact rib 232A and contact rib 232B of the second rib 232.

[0101] The liquid that flows downward along the non-contact rib 232A and the contact rib 232B is discharged to the outside of the housing 2 through the liquid outlet 23b. In other words, the second rib 232 guides the liquid that has entered the inside of the housing 2 to the liquid outlet 23b, and the liquid outlet 23b discharges the liquid that has flowed along the second rib 232 to the outside of the housing 2.

[0102] The third rib 233 protrudes to the left from the louver 24. The third rib 233 has a first part 233A and a second part 233B. The first part 233A is located above the non-contact rib 232A of the second rib 232. Multiple first parts 233A are formed and extend along the vertical direction. The second part 233B is located above the louver 24 and behind the first rib 231. The second part 233B extends along the front-rear direction.

[0103] As shown in Figures 10 and 11, the first rib 231 is located above the exhaust filter 72, which is supported by the right side wall 23. The first rib 231 is in contact with the first end face 722a of the exhaust filter 72. The first rib 231 is an example of a contact portion of the side wall.

[0104] The second rib 232 is located below the exhaust filter 72, which is supported by the right side wall 23. The non-contact rib 232A of the second rib 232 faces the second end face 722b of the exhaust filter 72 with a gap between them. Specifically, the first part 232Aa of the non-contact rib 232A faces the second end face 722b of the exhaust filter 72.

[0105] In other words, the non-contact rib 232A does not come into contact with the exhaust filter 72 attached to the right side wall 23. Because the non-contact rib 232A does not come into contact with the exhaust filter 72, it is possible to prevent liquid flowing along the non-contact rib 232A from coming into contact with the exhaust filter 72.

[0106] The contact rib 232B of the second rib 232 is in contact with the third end face 722c of the exhaust filter 72 attached to the right side wall 23. Specifically, the first part 232Ba of the contact rib 232B is in contact with the third end face 722c of the exhaust filter 72.

[0107] The first rib 231 and the second rib 232 are located in front of and above the exhaust filter 72, and below it, respectively. When attaching the exhaust filter 72 to the right side wall 23, the first rib 231 and the second rib 232 guide the exhaust filter 72 to the mounting position on the right side wall 23.

[0108] Thus, the second rib 232, which guides the liquid to the liquid outlet 23b, can also be used as a guide when attaching the exhaust filter 72 to the right side wall 23. In particular, the contact rib 232B of the second rib 232 comes into contact with the exhaust filter 72 attached to the right side wall 23, thus effectively guiding the exhaust filter 72.

[0109] The second rib 232 has a non-contact rib 232A and a contact rib 232B, which allows it to guide the exhaust filter 72 attached to the right side wall 23 while suppressing contact between the liquid flowing along the second rib 232 and the exhaust filter 72.

[0110] The third rib 233 is located to the right of the exhaust filter 72, which is supported by the right side wall 23. The first part 233A and the second part 233B of the third rib 233 are in contact with the right side permeable surface 721 of the exhaust filter 72. In addition, the second part 232Bb of the contact rib 232B of the second rib 232 is in contact with the right side permeable surface 721 of the exhaust filter 72.

[0111] The exhaust filter 72, supported by the right side wall 23, is positioned in the left-right direction, which is perpendicular to the direction along the right side wall 23, by having its right side permeable surface 721 in contact with the third rib 233. The third rib 233 is an example of a first positioning rib.

[0112] As shown in Figure 3, the exhaust filter 72 is positioned away from the louvers 24 by contacting the third rib 233. By positioning the exhaust filter 72 away from the louvers 24, it is possible to prevent liquid that has entered the interior of the housing 2 through the louvers 24 from coming into contact with the exhaust filter 72.

[0113] Furthermore, the exhaust filter 72 is positioned away from the louver 24 in the left-right direction by contacting the second part 232Bb of the contact rib 232B on the second rib 232. In other words, the second part 232Bb of the contact rib 232B on the second rib 232 also functions as a first positioning rib that positions the exhaust filter 72 away from the louver 24.

[0114] [Pressing element] As shown in Figure 10, a pressing body 73 is positioned between the non-contact rib 232A of the second rib 232 and the second end face 722b of the exhaust filter 72. The pressing body 73 is made of an elastic material such as a sponge and is formed in a rectangular parallelepiped shape.

[0115] The pressing body 73 is positioned in a compressed state between the non-contact rib 232A and the second end face 722b of the exhaust filter 72, and presses the exhaust filter 72 toward the first rib 231. As the exhaust filter 72 is pressed by the pressing body 73, the first end face 722a of the exhaust filter 72 comes into contact with the first rib 231.

[0116] In other words, the pressing body 73 presses the second end face 722b of the exhaust filter 72 so that the first end face 722a of the exhaust filter 72 and the first rib 231 are in contact. In this case, by positioning the pressing body 73 between the non-contact rib 232A of the second rib 232 and the second end face 722b of the exhaust filter 72, it is possible to stably press the exhaust filter 72. The pressing body 73 is an example of a pressing portion on a side wall.

[0117] The exhaust filter 72, supported by the right side wall 23, is positioned along the right side wall 23 by being pressed by the pressing body 73, causing its first end face 722a to press against the first rib 231, and its third end face 722c to contact the contact rib 232B of the second rib 232.

[0118] Furthermore, the exhaust filter 72, supported by the right side wall 23, is held in place by the pressing body 73 and the first rib 231 while being compressed in a direction along the right side wall 23. Therefore, it is possible to hold the exhaust filter 72 without placing any parts to press the exhaust filter 72 between the exhaust filter 72 and the fan 71, or extending the duct 27 of the right frame 26 toward the exhaust filter 72. This makes it possible to position the exhaust filter 72 between the fan 71 and the side wall 23 of the housing 2 while suppressing an increase in the size of the image forming apparatus 1.

[0119] [spring] As shown in Figures 10 to 13, the housing 2 has a spring 74. The spring 74 is formed by bending a metal wire and is conductive. The spring 74 is supported by the right side wall 23. A conductive and grounded sheet metal member 25 is attached to the right frame 26, and the spring 74 is electrically connected to the sheet metal member 25. The spring 74 is grounded by being electrically connected to the sheet metal member 25. The sheet metal member 25 is an example of a conductive component placed inside the housing.

[0120] The spring 74 has a first coil portion 741 and a second coil portion 742 formed in a cylindrical shape by winding a wire, a connecting portion 743 that connects the first coil portion 741 and the second coil portion 742, and a contact arm 744 that extends from the second coil portion 742 and contacts the second end face 722b of the exhaust filter 72.

[0121] The right side wall 23 has a first boss 23c and a second boss 23d that project to the left, towards the inside of the housing 2, below the second rib 232. The first coil portion 741 of the spring 74 is supported by the first boss 23c, and the second coil portion 742 is supported by the second boss 23d.

[0122] The connecting portion 743 extends rearward from the first coil portion 741, then bends upward, and then bends forward to extend forward and upward, connecting to the second coil portion 742. The contact arm 744 extends forward and downward from the second coil portion 742 and contacts the second end face 722b of the exhaust filter 72.

[0123] The contact arm 744, which contacts the second end face 722b of the exhaust filter 72, presses the exhaust filter 72 in a direction in which the first end face 722a of the exhaust filter 72 is pressed against the first rib 231. The direction in which the contact arm 744 of the spring 74 presses the exhaust filter 72 is the same direction in which the pressing body 73 presses the exhaust filter 72. In other words, the contact arm 744 of the spring 74 contacts the second end face 722b of the exhaust filter 72 in such a way that it generates a pressing force in the same direction as the pressing body 73.

[0124] By bringing the spring 74 into contact with the exhaust filter 72, the exhaust filter 72 can be grounded. Furthermore, by pressing the second end face 722b of the exhaust filter 72 with the spring 74, the first end face 722a of the exhaust filter 72 can be stably pressed against the first rib 231.

[0125] [Controlling fan operation] As shown in Figure 14, the image forming apparatus 1 includes a control unit 91 that controls the drive of the fan 71, an ambient temperature and humidity sensor 92 that detects the ambient temperature and humidity outside the housing 2, and an internal housing temperature and humidity sensor 93 that detects the temperature and humidity inside the housing 2. The ambient temperature and humidity sensor 92 is an example of a sensor that detects ambient temperature. The fan 71, the ambient temperature and humidity sensor 92, and the internal housing temperature and humidity sensor 93 are connected to the control unit 91.

[0126] The fan 71 can be driven at two rotational speeds, full speed and half speed, by the control unit 91. Full speed is an example of a first rotational speed, and half speed is an example of a second rotational speed that is slower than the first rotational speed. The fan 71 can also be stopped by the control unit 91.

[0127] As shown in Figure 15, the control unit 91 can control the operation of the fan 71 according to the operating state of the image forming apparatus 1 and the detection results of the ambient temperature and humidity sensor 92 and the housing temperature and humidity sensor 93.

[0128] For example, if the ambient temperature detected by the ambient temperature and humidity sensor 92 exceeds the fourth ambient temperature T4out, and the internal temperature detected by the internal housing temperature and humidity sensor 93 exceeds the second internal housing temperature T2in, the control unit 91 stops the printing operation of the image forming unit 5 to suppress the temperature inside the housing 2 from rising. In this case, the control unit 91 can drive the fan 71 at full speed or half speed. The fourth ambient temperature T4out can be set to, for example, 45°C, and the second internal housing temperature T2in can be set to, for example, 45°C.

[0129] Furthermore, within the range where the ambient temperature is below the fourth ambient temperature T4out and the temperature inside the housing is below the second housing temperature T2in, if the ambient temperature detected by the ambient temperature and humidity sensor 92 exceeds the first ambient temperature T1out, the control unit 91 drives the fan 71 at full speed regardless of whether the image forming apparatus 1 is in single-sided printing mode or double-sided printing mode. The first ambient temperature T1out can be set to, for example, 32°C.

[0130] Furthermore, within the range where the ambient temperature is below the fourth ambient temperature T4out and the temperature inside the housing is below the second housing temperature T2in, if the ambient temperature detected by the ambient temperature and humidity sensor 92 is below the first ambient temperature T1out, the control unit 91 drives the fan 71 at half speed when the image forming apparatus 1 is in single-sided printing mode, and drives the fan 71 at full speed when the image forming apparatus 1 is in double-sided printing mode.

[0131] Thus, the control unit 91 drives the fan 71 at full speed if the ambient temperature detected by the ambient temperature and humidity sensor 92 exceeds the first ambient temperature T1out, and performs single-sided printing on the sheet S by the image forming unit 5. If the ambient temperature detected by the ambient temperature and humidity sensor 92 is less than or equal to the first ambient temperature T1out, the control unit 91 drives the fan 71 at half speed.

[0132] Thus, under conditions where the ambient temperature is below the first ambient temperature T1out and single-sided printing is being performed on the sheet S, and the temperature inside the enclosure 2 does not rise significantly, it is possible to increase the amount of ozone removed by the exhaust filter 72 by slowing down the speed at which the ozone-containing air passes through the exhaust filter 72.

[0133] Furthermore, the control unit 91 can drive the fan 71 at full speed in a low-temperature, high-humidity environment where the ambient temperature detected by the ambient temperature and humidity sensor 92 is lower than the first ambient temperature T1out (i.e., a second ambient temperature T2out) and the ambient humidity detected by the ambient temperature and humidity sensor 92 is equal to or greater than the first ambient humidity H1out. In this case, the fan 71 can be driven at full speed both when the image forming apparatus 1 is in single-sided printing mode and when it is in double-sided printing mode.

[0134] The second ambient temperature T2out can be set to, for example, 10°C. The first ambient humidity H1out can be set to, for example, 80%.

[0135] In a low-temperature, high-humidity environment, the sheet S, which contains a large amount of moisture, is heated by the fuser 6, causing moisture to be released from the sheet S, which may lead to condensation inside the housing 2. In such conditions where condensation may occur inside the housing 2, the fan 71 can be driven at full speed to increase the exhaust volume, thereby quickly discharging the moisture inside the housing 2 to the outside and suppressing the occurrence of condensation.

[0136] Furthermore, the control unit 91 can drive the fan 71 for a certain period of time not only while the image forming unit 5 is printing on the sheet S, but also after the image forming unit 5 has finished printing on the sheet S. After printing on the sheet S is finished, the control unit 91 can drive the fan 71 at, for example, full speed or half speed. The certain period of time for driving the fan 71 after the completion of printing can be set to, for example, 10 minutes.

[0137] Here, the image forming apparatus 1 includes a continuous printing mode and an intermittent printing mode as printing modes for printing on the sheet S by the image forming unit 5.

[0138] As shown in Figure 16, in continuous printing mode, printing is performed continuously on multiple sheets S, and printing is completed after all sheets S have been printed. On the other hand, in intermittent printing mode, printing is performed on one or more sheets S, then printing is stopped for a predetermined time, and then printing is performed again on one or more sheets S after the printing has stopped. This process of printing and stopping is repeated until all sheets S have been printed and printing is completed.

[0139] The control unit 91 can drive the fan 71 for a certain period of time when printing is completed in continuous printing mode. The control unit 91 can also drive the fan 71 for a certain period of time when printing is stopped and when printing is completed in intermittent printing mode. In other words, "completion of printing" on the sheet S by the image forming unit 5 includes both "completion of printing" where printing has been completed on all sheets S, and "stopping of printing" which occurs during intermittent printing.

[0140] If the exhaust fan 71 is stopped immediately after the image forming unit 5 finishes printing on the sheet S, ozone-containing air will remain inside the housing 2 and may leak out through gaps in the housing 2. Therefore, by running the fan 71 for a predetermined time after printing is complete, the ozone-containing air inside the housing 2 can be exhausted after the ozone is removed by the exhaust filter 72, thereby preventing ozone-containing air from leaking out through gaps in the housing 2.

[0141] As shown in Figure 15, the control unit 91 can, for example, drive the fan 71 at half speed during printing stops in intermittent printing when the ambient temperature is above the third ambient temperature T3out and the internal temperature of the enclosure is above the first internal temperature T1in, within the range where the ambient temperature is below the fourth ambient temperature T4out and the internal temperature of the enclosure is below the second internal temperature T2in. Furthermore, after continuous printing and intermittent printing are completed, the control unit 91 can, for example, drive the fan 71 at half speed or full speed.

[0142] [Second Embodiment of Image Forming Apparatus] The image forming apparatus 1, which includes a housing 2 having an exhaust port 23a, a fan 71 for exhausting air from inside the housing 2, and an exhaust filter 72 positioned between the fan 71 and the housing 2, can also be configured as the image forming apparatus 1A shown in Figure 17.

[0143] As shown in Figures 17 and 18, the image forming apparatus 1A differs from the image forming apparatus 1 in that it has a housing 2A, a right frame 126, a fan 171, and an exhaust filter 172 instead of the housing 2, right frame 26, fan 71, and exhaust filter 72. The other components of the image forming apparatus 1A are the same as those of the image forming apparatus 1, so their description is omitted.

[0144] Enclosure 2A differs from enclosure 2 in that it has a right-side wall 123 instead of the right-side wall 23. The other configurations of enclosure 2A are the same as those of enclosure 2, so their explanation is omitted.

[0145] A fan 171 is housed inside the housing 2A to exhaust the air inside the housing 2A to the outside. The fan 171 is located to the right of the image forming unit 5 inside the housing 2A.

[0146] The right frame 126 is housed at the rightmost end of the enclosure 2A, and the enclosure 2A has a right side wall 123 that covers the right side of the right frame 126. The right side wall 123 is an example of a side wall provided by the enclosure. The right side wall 123 is located downstream of the fan 171 in the exhaust direction of the fan 171.

[0147] The right side wall 123 has an outer protruding wall 123A that protrudes to the right more than the other parts. The right side wall 123 has an exhaust port 123a that penetrates the right side wall 123 in the left-right direction. The exhaust port 123a is formed in the outer protruding wall 123A. The exhaust port 123a is formed in a circular shape. The right side wall 123 is an example of a side wall having an exhaust port.

[0148] Fan 171 is supported by the right frame 126 and is positioned so as to overlap with the exhaust port 123a when viewed from the left or right. When fan 171 is driven, an airflow is generated from left to right, and the airflow created by fan 171 exhausts the air inside the housing 2A to the outside of the housing 2A through the exhaust port 123a.

[0149] (fan) As shown in Figure 19, the right frame 126 has a duct 127 that penetrates in the left-right direction. The fan 171 is fitted into the duct 127. The fan 171 is supported by the right frame 126 by being fitted into the duct 127. The right frame 126 is an example of a frame that supports a fan.

[0150] The fan 171 has a rotating shaft 1711 extending in the left-right direction, blades 1712 fixed to the rotating shaft 1711, and a case 1713 that rotatably supports the rotating shaft 1711, and is an axial flow fan that sends out air along the axial direction of the rotating shaft 1711.

[0151] The outer shape of the case 1713 in the first fan 171 is rectangular. The outer shape of the case 1713 forms the outer shape of the fan 171. The case 1713 has a circular vent 1713a that penetrates in the left-right direction, and the blades 1712 are located within the area enclosed by the vent 1713a. Air exhausted by the fan 171 passes through the vent 1713a.

[0152] The duct 127 of the right frame 126 is formed in a rectangular shape, and a pressing hook 1271 is formed on the rear wall 127a of the duct 127 to press the fan 171 fitted into the duct 127 forward. The pressing hook 1271 is an example of a fan pressing part that presses the fan. In addition, the fan 171 fitted into the duct 127 is pulled downward by gravity.

[0153] Therefore, the fan 171 fitted into the duct 127 is pressed forward and downward by the pressing hook 1271 and gravity, and is positioned at the front lower end within the duct 127. In this way, the pressing hook 1271 presses the fan 171 so that the direction of pressure on the duct 127 of the fan 171 is forward and downward.

[0154] (Luba) As shown in Figures 18 and 20, the right side wall 123 of the housing 2A has a louver 124 positioned at the exhaust port 123a. The louver 124 is an example of a second louver. The louver 124 is located to the right of the fan 171. The louver 124 connects the inside and outside of the housing 2A and regulates the direction of exhaust of the air exhausted through the exhaust port 123a. The louver 124 is detachably attached to the outer protruding wall 123A of the right side wall 123.

[0155] The louver 124 has a circular frame 1240 and a plurality of fins 1241 arranged within the area enclosed by the frame 1240. The frame 1240 is detachably fitted into the exhaust port 123a. The frame 1240 fitted into the exhaust port 123a is rotatable in the circumferential direction about the circular center of the exhaust port 123a.

[0156] In the state shown in Figure 20, the louvers 124 have long, plate-like blades that extend in the front-to-back direction and are inclined upward from left to right. Therefore, air exhausted from left to right is redirected diagonally upward to the right as it passes through the louvers 124.

[0157] The louver 124 can change the direction of air exhaust because the inclination direction of the slats 1241 changes as it rotates in the circumferential direction. In this way, the louver 124, which regulates the direction of air exhaust, is movable so as to change the direction of air exhaust.

[0158] (Exhaust filter) As shown in Figures 18 and 21, the image forming apparatus 1A includes an exhaust filter 172 located between the outer protruding wall 123A of the right side wall 123 and the fan 171 in the left-right direction. When viewed from the left-right direction, the exhaust filter 172 is positioned to overlap with the louvers 124 formed on the outer protruding wall 123A of the right side wall 123. The exhaust filter 172 is supported by the right side wall 123.

[0159] The exhaust filter 172 is composed of a honeycomb filter, for example, in which the filter material is formed in a honeycomb shape. As the filter material constituting the exhaust filter 172, for example, paper supported with an ozone decomposition catalyst such as manganese dioxide or activated carbon, a metal such as aluminum, or ceramics can be used. In this embodiment, the exhaust filter 172 is conductive.

[0160] As shown in Figure 22, the exhaust filter 172 is formed in a sheet shape. The exhaust filter 172 has a permeable surface 1721 through which exhaust air passes, and a peripheral end surface 1722 that is perpendicular to the permeable surface 1721 and located on the outer circumference of the exhaust filter 172. The permeable surface 1721 is wider than the peripheral end surface 1722. The exhaust filter 172 is positioned so that the permeable surface 1721 faces the right side wall 123.

[0161] The permeable surface 1721 of the exhaust filter 172 is formed in a rectangular shape with four corners beveled. The peripheral end surface 1722 of the exhaust filter 172 has a first end surface 1722a located in the beveled front lower portion of the permeable surface 1721, a second end surface 1722b located in the beveled rear upper portion of the permeable surface 1721, a third end surface 1722c located in the lower edge portion of the permeable surface 1721, and a fourth end surface 1722d located in the beveled front upper portion of the permeable surface 1721.

[0162] As shown in Figure 19, the exhaust filter 172 is sized to cover the vent 1713a of the fan 171. The exhaust filter 172 is sized to be equivalent to the outer dimensions of the case 1713. The exhaust filter 172 can be sized so that it does not protrude from the outer dimensions of the case 1713 when viewed from the left-right direction, which is the direction in which the vent 1713a penetrates.

[0163] In this way, the exhaust filter 172 can be formed to cover the vent 1713a of the fan 171 and to be sized so that it does not protrude from the outer shape of the fan 171 when viewed from the left and right directions, which are the directions in which the vent 1713a penetrates. By configuring it in this way, the exhaust filter 172 does not become unnecessarily large, and it is possible to reduce costs.

[0164] Within the housing 2A, ozone is generated by components that generate discharges into the atmosphere, such as the charger 57 of the process cartridge 50. In addition, toner contained in the process cartridge 50 may float within the housing 2A.

[0165] The air inside the housing 2A is drawn in by the fan 171, passes through the exhaust filter 172 to remove ozone and dust such as toner, and is then exhausted to the outside of the housing 2A through the louvers 124. Therefore, the amount of ozone and dust contained in the air inside the housing 2A that is exhausted by the fan 171 can be reduced.

[0166] The exhaust filter 172 only needs to be a filter capable of removing at least toner and other dust particles from the air it passes through. Alternatively, the exhaust filter 172 can be an ozone filter capable of removing ozone in addition to toner and other dust particles from the air it passes through.

[0167] By using an ozone filter as the exhaust filter 172, which is capable of removing ozone from the air exhausted by the fan 171, it is possible to reduce the amount of ozone contained in the exhaust from the fan 171. This prevents ozone generated inside the enclosure 2A from leaking out to the outside of the enclosure 2A.

[0168] (Right side wall) As shown in Figures 23 and 24, the right side wall 123 has a first rib 1231, a second rib 1232, a third rib 1233, and a fourth rib 1234 that protrude toward the interior side of the housing 2A.

[0169] The first rib 1231 is located in front of and below the louver 124 on the outer protruding wall 123A of the right side wall 123, and protrudes to the left from the outer protruding wall 123A. The first rib 1231 extends along the outer protruding wall 123A and slopes downward as it is directed towards the rear.

[0170] The second rib 1232 is located above and behind the louver 124 on the outer protruding wall 123A of the right side wall 123, and protrudes to the left from the outer protruding wall 123A. The second rib 1232 extends along the outer protruding wall 123A and slopes downward as it approaches the rear. The second rib 1232 is an example of a protruding wall that protrudes toward the interior side of the housing.

[0171] The third rib 1233 is located behind and below the louver 124 on the outer protruding wall 123A of the right side wall 123, and protrudes to the left from the outer protruding wall 123A. The third rib 1233 extends along the outer protruding wall 123A. The third rib 1233 extends approximately in the front-rear direction.

[0172] The fourth rib 1234 is located in front of and above the louver 124 on the outer protruding wall 123A of the right side wall 123, and protrudes to the left from the outer protruding wall 123A. The fourth rib 1234 extends along the outer protruding wall 123A and slopes downward as it extends forward.

[0173] As shown in Figures 21 and 25, the first rib 1231 is located in front of and below the exhaust filter 172, which is supported by the outer protruding wall 123A of the right side wall 123. The first rib 1231 is in contact with the first end face 1722a of the exhaust filter 172. The first rib 1231 is an example of a contact portion of the side wall.

[0174] The second rib 1232 is located rear and above the exhaust filter 172, which is supported by the outer protruding wall 123A of the right side wall 123. The second rib 1232 faces the second end face 1722b of the exhaust filter 172 with a gap between them.

[0175] The third rib 1233 is located rear and below the exhaust filter 172, which is supported by the outer protruding wall 123A of the right side wall 123. The third rib 1233 is in contact with the third end face 1722c of the exhaust filter 172.

[0176] The fourth rib 1234 is located in front of and above the exhaust filter 172, which is supported by the outer protruding wall 123A of the right side wall 123. The fourth rib 1234 faces the fourth end face 1722d of the exhaust filter 172 with a gap between them.

[0177] The first rib 1231, the second rib 1232, the third rib 1233, and the fourth rib 1234 are located in front-lower, rear-upper, rear-lower, and front-upper positions, respectively, of the exhaust filter 72. This allows the first rib 1231, the second rib 1232, the third rib 1233, and the fourth rib 1234 to guide the exhaust filter 172 to its mounting position relative to the outer protruding wall 123A of the right side wall 123 when the exhaust filter 172 is attached to the right side wall 123.

[0178] As shown in Figures 23 to 25, the right side wall 123 has a fifth rib 1235 and a sixth rib 1236 that protrude toward the interior side of the housing 2A. The fifth rib 1235 and the sixth rib 1236 are formed along the periphery of the exhaust port 123a on the outer protruding wall 123A of the right side wall 123. The fifth rib 1235 and the sixth rib 1236 protrude further toward the interior side of the housing 2A than the louvers 124. The amount of leftward protrusion of the fifth rib 1235 is greater than the amount of leftward protrusion of the sixth rib 1236.

[0179] The fifth rib 1235 has a first part 1235a, a second part 1235b, a third part 1235c, and a fourth part 1235d. The first part 1235a is located at the upper end of the exhaust port 123a, the second part 1235b is located at the lower end of the exhaust port 123a, the third part 1235c is located at the front end of the exhaust port 123a, and the fourth part 1235d is located at the rear end of the exhaust port 123a.

[0180] The sixth rib 1236 has a first part 1236a, a second part 1236b, a third part 1236c, and a fourth part 1236d.

[0181] Part 1236a of the 6th rib 1236 is located between Part 1235a and Part 31235c of the 5th rib 1235. Part 21236b of the 6th rib 1236 is located between Part 21235b and Part 31235c of the 5th rib 1235. Part 31236c of the 6th rib 1236 is located between Part 21235b and Part 41235d of the 5th rib 1235. Part 41236d of the 6th rib 1236 is located between Part 1235a and Part 41235d of the 5th rib 1235.

[0182] The first part 1236a of the sixth rib 1236 faces the fourth rib 1234. The second part 1236b of the sixth rib 1236 faces the first rib 1231. The third part 1236c of the sixth rib 1236 faces the third rib 1233. The fourth part 1236d of the sixth rib 1236 faces the second rib 1232.

[0183] The sixth rib 1236 is located to the right of the exhaust filter 172, which is supported by the outer protruding wall 123A of the right side wall 123. The sixth rib 1236 is in contact with the right side permeable surface 1721 of the exhaust filter 172.

[0184] The first part 1236a of the sixth rib 1236 is in contact with the front upper part of the exhaust filter 172. The second part 1236b of the sixth rib 1236 is in contact with the front lower part of the exhaust filter 172. The third part 1236c of the sixth rib 1236 is in contact with the rear lower part of the exhaust filter 172. The fourth part 1236d of the sixth rib 1236 is in contact with the rear upper part of the exhaust filter 172.

[0185] The exhaust filter 172, supported by the right side wall 123, is positioned in the left-right direction, which is perpendicular to the direction along the right side wall 123, by having its right side permeable surface 1721 in contact with the sixth rib 1236.

[0186] As shown in Figure 18, the exhaust filter 172 is positioned away from the louver 124 by contacting the sixth rib 1236. In other words, the sixth rib 1236 is in contact with the exhaust filter 172, which is positioned away from the louver 124. The sixth rib 1236 is an example of a second positioning rib that is in contact with the exhaust filter, which is positioned away from the second louver.

[0187] In this way, the exhaust filter 172 is positioned away from the louver 124 by the sixth rib 1236, so that the moving louver 124 and the exhaust filter 172 do not come into contact, thereby preventing damage to the exhaust filter 172.

[0188] Furthermore, the first part 235a, second part 235b, third part 235c, and fourth part 235d of the fifth rib 235 are each capable of contacting the first exhaust filter 72, and by contacting the first exhaust filter 72, they can be positioned along the right side wall 23 of the first exhaust filter 72.

[0189] (Pressing element) As shown in Figures 21 and 25, a pressing body 173 is positioned between the second rib 1232 and the second end face 1722b of the exhaust filter 172. The pressing body 173 is made of an elastic material such as sponge and is formed in a rectangular parallelepiped shape.

[0190] The pressing body 173 is positioned in a compressed state between the second rib 1232 and the second end face 1722b of the exhaust filter 172, pressing the exhaust filter 172 toward the first rib 1231. As the exhaust filter 172 is pressed by the pressing body 173, the first end face 1722a of the exhaust filter 172 comes into contact with the first rib 1231.

[0191] In other words, the pressing body 173 presses the second end face 1722b of the exhaust filter 172 such that the first end face 1722a of the exhaust filter 172 and the first rib 1231 are in contact. In this case, by positioning the pressing body 173 between the second rib 1232 and the second end face 1722b of the exhaust filter 172, it is possible to stably press the exhaust filter 172. The pressing body 173 is an example of a pressing portion on a side wall.

[0192] The exhaust filter 172, supported by the right side wall 123, is positioned along the right side wall 123 by being pressed by the pressing body 173, causing its first end face 1722a to press against the first rib 1231 and its third end face 1722c to contact the third rib 1233.

[0193] Furthermore, the exhaust filter 172, supported by the right side wall 123, is held in place by the pressing body 173 and the first rib 1231 while being compressed in a direction along the right side wall 123. Therefore, it is possible to hold the exhaust filter 172 without placing any parts to press the exhaust filter 172 between the exhaust filter 172 and the fan 171, or extending the duct 127 of the right frame 126 toward the exhaust filter 172. This makes it possible to position the exhaust filter 172 between the fan 171 and the side wall 123 of the housing 2A while suppressing an increase in the size of the image forming apparatus 1A.

[0194] (Relationship between the direction of pressure applied by the fan to the duct and the direction of pressure applied by the pressing element to the exhaust filter) The exhaust filter 172 is pressed forward and downward by the pressing body 173. The fan 171 is also pressed forward and downward relative to the duct 127 by the pressing hook 1271. As a result, the direction of pressure applied to the exhaust filter 172 by the pressing body 173 and the direction of pressure applied to the duct 127 by the fan 171 by the pressing hook 1271 are the same.

[0195] In other words, the pressing hook 1271 presses the fan 171 such that the direction in which the fan 171 presses against the duct 127 on the frame 126 of the fan 171 is the same direction in which the pressing body 173 presses against the exhaust filter 712.

[0196] This configuration makes it possible to accurately align the exhaust filter 172, which is held on the right side wall 123 of the enclosure 2A, with the fan 171, which is held on the frame 126.

[0197] (Control of fan operation) The control unit 91 can also control the drive of the fan 171 in the image forming apparatus 1A, in the same way as the fan 71 in the image forming apparatus 1. In other words, if the ambient temperature detected by the ambient temperature and humidity sensor 92 exceeds the first ambient temperature T1out, the control unit 91 drives the fan 171 at full speed and performs single-sided printing on the sheet S by the image forming unit 5, and if the ambient temperature detected by the ambient temperature and humidity sensor 92 is less than or equal to the first ambient temperature T1out, the control unit 91 drives the fan 171 at half speed.

[0198] This makes it possible to increase the amount of ozone removed by the exhaust filter 172 by slowing down the speed at which the ozone-containing air passes through the exhaust filter 172, under conditions where the temperature inside the enclosure 2A does not rise significantly.

[0199] Furthermore, the control unit 91 can drive the fan 171 at full speed in a low-temperature, high-humidity environment where the ambient temperature detected by the ambient temperature and humidity sensor 92 is a second ambient temperature T2out which is lower than the first ambient temperature T1out, and the ambient humidity detected by the ambient temperature and humidity sensor 92 is the first ambient humidity H1out. In this case, the fan 171 can be driven at full speed both when the image forming apparatus 1A is in single-sided printing mode and when it is in double-sided printing mode. This allows moisture inside the housing 2A to be quickly discharged to the outside of the housing 2A, thereby suppressing the occurrence of condensation.

[0200] Furthermore, the control unit 91 can drive the fan 171 for a certain period of time not only while the image forming unit 5 is printing on the sheet S, but also after the image forming unit 5 has finished printing on the sheet S. This allows the air inside the housing 2A containing ozone to be exhausted after the ozone has been removed by the exhaust filter 172, thereby preventing ozone-containing air from leaking out of the gaps in the housing 2A. [Explanation of symbols]

[0201] 1, 1A Image forming device 2, 2A enclosure 5 Image forming unit 6. Fuser 23, 123 Right side wall 23a, 123a Exhaust port 23b Liquid outlet 24, 124 louvers 26, 126 Right frame 27, 127 ducts 54 Photosensitive drum 57. Charger 71,171 fans 72, 172 Exhaust filter 73, 173 Pressing body 74 Springs 91 Control Unit 92. Ambient temperature and humidity sensor 713, 1713 cases 713a, 1713a Ventilation openings 231, 1231 First Rib 232, 1232 Second Rib 232A Non-contact rib 232B Contact Rib 233 Third Rib 721, 1721 Transparent surface 722, 1722 Peripheral end surface 722a, 1722a 1st end face 722b, 1722b 2nd end face 1236 Sixth Rib 1271 Pressure Hook S Seat H1out 1st environment humidity T1out 1st environment temperature T2out 2nd environment temperature

Claims

1. A housing having a side wall with an exhaust port, A fan for exhausting air from inside the enclosure, The system includes an exhaust filter disposed between the side wall and the fan, The image forming apparatus is characterized in that the side wall has a contact portion that abuts against a first end surface among the circumferential end surfaces located on the outer circumference of the exhaust filter, and a pressing portion that presses against a second end surface, which is different from the first end surface, among the circumferential end surfaces, so that the first end surface and the contact portion are in pressure contact.

2. The side wall has a protruding wall that projects toward the interior side of the housing, The image forming apparatus according to claim 1, wherein the pressing portion is an elastic body disposed between the protruding wall and the second end face of the exhaust filter.

3. The pressing part is made of sponge, The image forming apparatus according to claim 2, wherein the housing is further formed of a metal member and comprises a spring electrically connected to a conductive component disposed within the housing, the spring contacting the second end face of the exhaust filter so as to generate a pressing force that presses in the same direction as the sponge.

4. The exhaust filter has a permeable surface that faces the side wall and through which the exhausted air passes, The aforementioned side wall is A first louver is placed in the exhaust port and restricts the direction of air exhaust, A first rib, which is the contact portion that protrudes toward the inside of the housing, is located above the exhaust filter and contacts the first end face of the exhaust filter, A second rib protrudes toward the inside of the housing and is located below the exhaust filter, A liquid outlet located below the second rib, which discharges the liquid flowing along the second rib to the outside of the housing, The housing has a first positioning rib that protrudes toward the inside and contacts the permeable surface of the exhaust filter, positioning the exhaust filter at a position away from the first louver, The image forming apparatus according to any one of claims 1 to 3, wherein the second rib guides the exhaust filter, which is attached to the side wall, to the mounting position on the side wall, and guides the liquid to the liquid outlet.

5. The aforementioned second rib is A non-contact rib attached to the side wall that does not come into contact with the exhaust filter, The image forming apparatus according to claim 4, further comprising a contact rib that intersects the vertical direction and is positioned differently from the non-contact rib in a direction along the side wall, and that contacts the exhaust filter attached to the side wall.

6. The aforementioned side wall is A second louver positioned at the exhaust port and regulating the direction of air exhaust, the second louver being movable so as to change the direction of air exhaust, The image forming apparatus according to claim 1, further comprising: a second positioning rib that protrudes inward from the second louver and contacts the exhaust filter, which is positioned at a distance from the second louver.

7. The frame further comprises the aforementioned fan, The image forming apparatus according to claim 1, wherein the frame has a fan pressing portion that presses the fan such that the direction in which the fan presses the frame is the same direction in which the pressing portion presses the exhaust filter.

8. The aforementioned fan has a vent through which the exhaust air passes, The image forming apparatus according to claim 1, wherein the exhaust filter covers the vent of the fan and is formed to a size that does not protrude from the outer shape of the fan when viewed from the direction through which the vent passes.

9. The housing contains an image forming unit that forms an image on a sheet, The image forming unit comprises a drum for forming a toner image on a sheet, a charger for charging the drum, and a fuser for fixing the toner image formed on the sheet. The image forming apparatus according to claim 1, wherein the filter is an ozone filter capable of removing ozone from the air passing through it.

10. An image forming unit capable of printing an image onto a sheet, A control unit that controls the operation of the aforementioned fan, It is further equipped with a sensor that detects ambient temperature, The fan can be driven at a first rotational speed and a second rotational speed slower than the first rotational speed. The control unit, If the ambient temperature detected by the sensor exceeds the first ambient temperature, the fan is driven at the first rotational speed. The image forming apparatus according to claim 1, wherein the image forming unit performs single-sided printing on a sheet, and when the ambient temperature detected by the sensor is below the first ambient temperature, the fan is driven at a second rotational speed.

11. The aforementioned sensor is capable of detecting ambient humidity, The image forming apparatus according to claim 10, wherein the control unit drives the fan at a first rotational speed when the ambient temperature detected by the sensor is lower than or equal to a second ambient temperature which is lower than the first ambient temperature, and the ambient humidity detected by the sensor is equal to or greater than the first ambient humidity.

12. The image forming apparatus according to claim 10, wherein the control unit drives the fan for a predetermined time after the image forming unit has finished printing on the sheet.

Images