Image forming apparatus

Abstract

To provide an image forming apparatus that improves performance to block heat from a fixing unit.SOLUTION: An image forming apparatus comprises: a rotatable image carrier; a developing member that supplies toner to the image carrier to form a toner image on the image carrier; a transfer member that transfers the toner image formed on the image carrier to a sheet; a cleaning member that is in contact with the surface of the image carrier to remove toner from the surface of the image carrier; a toner recovery container that recovers the toner removed by the cleaning member from the surface of the image carrier; a fixing unit that fixes the toner image transferred to the sheet by the transfer member to the sheet; and a duct that forms an air channel through which air is directed to the outside of the image forming apparatus passes, and that is provided between the toner recovery container and the fixing unit. The duct has a first wall part that faces the fixing unit, and a second wall part that faces the toner recovery container. The first wall part is inclined with respect to the second wall part.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to an image forming apparatus that forms an image on a sheet.

Background Art

[0002] Conventionally, an electrophotographic image forming apparatus including a process cartridge and a fixing device has been proposed (see Patent Document 1). The process cartridge is configured by integrally incorporating a photosensitive drum, a cleaner, a primary charger, a developing device, and the like. A cross-flow fan is disposed between the fixing device and the process cartridge. The cross-flow fan sucks air heated by the fixing device, which is a heat source, and discharges it outward of the image forming apparatus. The blades and the housing of the cross-flow fan also function as a partition plate that blocks the propagation of radiant heat from the fixing device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, there is room for improvement in the heat insulation performance of the blades and the housing of the cross-flow fan described in Patent Document 1.

[0005] An object of the present invention is to provide an image forming apparatus having improved heat insulation performance of heat from a fixing unit.

Means for Solving the Problems

[0006] The present invention relates to an image forming apparatus that forms a toner image on a sheet, including a rotatable image carrier, a developing member that forms a toner image on the image carrier by supplying toner to the image carrier, a transfer member that transfers the toner image formed on the image carrier to the sheet, a cleaning member that contacts the surface of the image carrier and removes toner from the surface of the image carrier, a toner recovery container that recovers the toner removed from the surface of the image carrier by the cleaning member, a fixing unit that fixes the toner image transferred to the sheet by the transfer member to the sheet, a duct that forms an air passage through which air directed to the outside of the image forming apparatus passes and is provided between the toner recovery container and the fixing unit, the duct having a first wall portion facing the fixing unit and a second wall portion facing the toner recovery container, and the first wall portion being inclined with respect to the second wall portion.

[0007] Further, the present invention relates to an image forming apparatus that forms a toner image on a sheet, including a rotatable image carrier, a developing member that forms a toner image on the image carrier by supplying toner to the image carrier, a transfer member that transfers the toner image formed on the image carrier to the sheet, a cleaning member that contacts the surface of the image carrier and removes toner from the surface of the image carrier, a toner recovery container that recovers the toner removed from the surface of the image carrier by the cleaning member, a fixing unit that fixes the toner image transferred to the sheet by the transfer member to the sheet, a duct that forms an air passage through which air directed to the outside of the image forming apparatus passes and is provided between the toner recovery container and the fixing unit, the duct having a duct having a first wall portion facing the fixing unit and a second wall portion facing the toner recovery container, and at least one of the first wall portion and the second wall portion having a plurality of protruding portions protruding toward the air passage.

[0008] Further, the present invention relates to an image forming apparatus for forming a toner image on a sheet, comprising a rotatable image carrier, a developing member for forming a toner image on the image carrier by supplying toner to the image carrier, a transfer member for transferring the toner image formed on the image carrier to the sheet, a cleaning member that contacts the surface of the image carrier and removes toner from the surface of the image carrier, a toner recovery container for recovering the toner removed from the surface of the image carrier by the cleaning member, a fixing unit for fixing the toner image transferred to the sheet by the transfer member to the sheet, a duct provided between the toner recovery container and the fixing unit and forming an air passage through which air flows toward the outside of the image forming apparatus, wherein the duct has a first wall portion facing the fixing unit and a second wall portion facing the toner recovery container, and at least one of the first wall portion and the second wall portion has a plurality of openings communicating with the air passage.

[0009] Further, the present invention relates to an image forming apparatus for forming a toner image on a sheet, comprising a rotatable image carrier, a developing member for forming a toner image on the image carrier by supplying toner to the image carrier, a transfer member for transferring the toner image formed on the image carrier to the sheet, a cleaning member that contacts the surface of the image carrier and removes toner from the surface of the image carrier, a toner recovery container for recovering the toner removed from the surface of the image carrier by the cleaning member, a fixing unit for fixing the toner image transferred to the sheet by the transfer member to the sheet, a duct provided between the toner recovery container and the fixing unit and forming an air passage through which air flows toward the outside of the image forming apparatus, wherein the duct has a first wall portion facing the fixing unit, a second wall portion facing the toner recovery container, and a partition wall disposed between the first wall portion and the second wall portion, and the partition wall divides the air passage into a first air passage formed between the first wall portion and a second air passage formed between the second wall portion.

[0010] Furthermore, the present invention relates to an image forming apparatus that forms a toner image on a sheet, comprising: a rotatable image carrier; a developing member that forms a toner image on the image carrier by supplying toner to the image carrier; a transfer member that transfers the toner image formed on the image carrier to the sheet; a cleaning member that contacts the surface of the image carrier and removes toner from the surface of the image carrier; a toner collection container that collects the toner removed from the surface of the image carrier by the cleaning member; a fixing unit that fixes the toner image transferred to the sheet by the transfer member to the sheet; and a duct that forms an air passage through which air flows toward the outside of the image forming apparatus and is provided between the toner collection container and the fixing unit. The fixing unit includes a fixing member that heats the toner image on the sheet and a fixing cover that covers the fixing member. The duct has a first wall portion facing the fixing unit and a second wall portion facing the toner collection container. The first wall portion of the duct is arranged downstream in the sheet conveyance direction from the straight line so as not to intersect the straight line extending vertically through the upstream end of the fixing cover in the sheet conveyance direction when viewed in the rotational axis direction of the image carrier.

[0011] Further, the present invention relates to an image forming apparatus that forms a toner image on a sheet, comprising a rotatable image carrier, a developing member that forms a toner image on the image carrier by supplying toner to the image carrier, a transfer member that transfers the toner image formed on the image carrier to the sheet, a cleaning member that contacts the surface of the image carrier and removes toner from the surface of the image carrier, a toner recovery container that recovers the toner removed from the surface of the image carrier by the cleaning member, a fixing unit that fixes the toner image transferred to the sheet by the transfer member, a duct that forms an air passage through which air flows toward the outside of the image forming apparatus and is provided between the toner recovery container and the fixing unit, the duct having a first wall portion facing the fixing unit and a second wall portion facing the toner recovery container, and a heat insulating member attached to at least one of the first wall portion and the second wall portion and having a lower thermal conductivity than the duct.

[0012] Further, the present invention relates to an image forming apparatus that forms a toner image on a sheet, comprising a rotatable image carrier, an exposure device that exposes the image carrier, a developing member that forms a toner image on the image carrier by supplying toner to the image carrier, a transfer member that transfers the toner image formed on the image carrier to the sheet, a cleaning member that contacts the surface of the image carrier and removes toner from the surface of the image carrier, a toner recovery container that recovers the toner removed from the surface of the image carrier by the cleaning member, a fixing unit that fixes the toner image transferred to the sheet by the transfer member, a support member that supports the exposure device, a duct that forms an air passage through which air flows toward the outside of the image forming apparatus and is provided between the toner recovery container and the fixing unit and is supported by the support member, the duct having a first wall portion facing the fixing unit and a second wall portion facing the toner recovery container, and a heat insulating member disposed between the support member and the duct and having a lower thermal conductivity than the duct.

[0013] Further, the present invention provides an image forming apparatus for forming a toner image on a sheet, comprising: a rotatable image carrier; an exposure device for exposing the image carrier; a developing member for forming a toner image on the image carrier by supplying toner to the image carrier; a transfer member for transferring the toner image formed on the image carrier to the sheet; a cleaning member for contacting the surface of the image carrier and removing toner from the surface of the image carrier; a toner recovery container for recovering the toner removed from the surface of the image carrier by the cleaning member; a fixing unit for fixing the toner image transferred to the sheet by the transfer member; a support member for supporting the exposure device; and a duct provided between the toner recovery container and the fixing unit, forming an air passage through which air flows toward the outside of the image forming apparatus and supported by the support member, the duct having a first wall portion facing the fixing unit and a second wall portion facing the toner recovery container, wherein the duct has a lower thermal conductivity than the support member.

[0014] Also, the present invention relates to an image forming apparatus that forms a toner image on a sheet, including a rotatable image carrier, an exposure device that exposes the image carrier, a developing member that forms a toner image on the image carrier by supplying toner to the image carrier, a transfer member that transfers the toner image formed on the image carrier to the sheet, a cleaning member that contacts the surface of the image carrier and removes toner from the surface of the image carrier, a toner recovery container that recovers the toner removed from the surface of the image carrier by the cleaning member, a fixing unit that fixes the toner image transferred to the sheet by the transfer member to the sheet, a support member that supports the exposure device, and a duct that forms an air passage through which air outside the image forming apparatus passes, is provided between the toner recovery container and the fixing unit, and is supported by the support member, the duct having a first wall portion facing the fixing unit and a second wall portion facing the toner recovery container, and a guide member that is disposed on the opposite side of the toner recovery container with respect to a conveyance path through which the sheet passes between the transfer member and the fixing unit and overlaps the fixing unit in the sheet conveyance direction, and guides the sheet toward the fixing nip portion of the fixing unit, wherein the duct is disposed so as to overlap the guide member in the sheet conveyance direction.

Effects of the Invention

[0015] According to the present invention, the heat insulation performance from the fixing unit can be improved.

Brief Description of the Drawings

[0016]

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Mode for Carrying Out the Invention

[0017] Hereinafter, with reference to the drawings, preferred embodiments of the present invention will be exemplarily described in detail. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in this embodiment should be appropriately changed according to the configuration of the apparatus to which the invention is applied and various conditions, and the scope of the present invention is not intended to be limited to the following embodiments.

[0018] <Example 1> [Overall Configuration of Image Forming Apparatus] First, an example of the overall configuration of the image forming apparatus in this embodiment will be described. The image forming apparatus A according to this embodiment is a laser printer using the electrophotographic method. Note that the image forming apparatus includes a printer, a copier, a facsimile machine, and a multifunction machine, and refers to an apparatus that forms an image on a sheet used as a recording medium based on image information input from an external PC or image information read from a document. In addition, in addition to the main body having an image forming function, the image forming apparatus may be connected with accessory devices such as an optional feeder, an image reading device, and a sheet processing device, and the entire system to which such accessory devices are connected is also a kind of image forming apparatus. Further, the image forming apparatus has an image forming unit capable of forming a monochrome toner image or a full-color toner image on a recording material as a sheet.

[0019] FIG. 1 is a schematic cross-sectional view of an image forming apparatus A according to Embodiment 1. As shown in FIG. 1, the image forming apparatus A has a photosensitive drum 1 which is a drum-type (cylindrical) electrophotographic photoreceptor as an image carrier. The photosensitive drum 1 is rotatably supported by a device main body M of the image forming apparatus A, and is rotationally driven by a driving source (not shown). Around the photosensitive drum 1, in the rotational direction of the photosensitive drum 1, a charging roller 2, an exposure device 3, a developing device 4, a transfer roller 5, and a cleaning device 6 are arranged in sequence.

[0020] Also, a recording material cassette 7 for storing a recording material P such as paper is arranged at the lower middle part of the device main body M in the drawing. Along the conveyance path of the recording material P from the recording material cassette 7, in sequence, a pickup roller 8, a feed roller 9, a retard roller 10, a conveyance roller pair 11, a registration roller pair 12, a registration roller shutter 13, a top sensor 14, a pre-transfer upper guide 15, a pre-transfer lower guide 16, the transfer roller 5, a charge removal needle 17, a conveyance guide 18, a suction sheet metal 19, a pre-fixing guide 32, a fixing device 20, a discharge sensor 21, a discharge roller pair 22, and a discharge tray 23 are arranged. These photosensitive drum 1, charging roller 2, exposure device 3, developing device 4, transfer roller 5, cleaning device 6, and the exposure device 3 described later constitute an image forming unit 150 for forming an image (toner image) on the recording material P.

[0021] Next, the image forming operation will be described. The photosensitive drum 1 is rotationally driven by a driving source (not shown) in the clockwise direction in FIG. 1 at a process speed (circumferential speed) of 280 mm / second. In this embodiment, the outer diameter of the photosensitive drum 1 is 24 mm. The surface of the rotating photosensitive drum 1 is uniformly charged to a predetermined potential with a predetermined polarity (negative polarity in this embodiment) by the charging roller 2. At this time, a charging bias (charging voltage) is applied to the charging roller 2 from a charging power source (high voltage power source) (not shown). Image exposure is irradiated onto the charged surface of the photosensitive drum 1 based on image information input from a host computer (not shown) by the exposure device 3, and an electrostatic latent image (electrostatic image) is formed by removing the negative charges in the exposed portions.

[0022] The electrostatic latent image formed on the photosensitive drum 1 is developed into a toner image by the developing device 4. The developing device 4 uses a contact development method as the developing method. Inside the developing container of the developing device 4, a stirring rod 28 is provided. By rotating in the clockwise direction in the figure, the stirring rod 28 temporarily stores toner (not shown) in the vicinity of the contact portion between the developing roller 25 and the toner supply roller 26. The once-stored toner is supplied by the toner supply roller 26 rotating counterclockwise in the figure so as to be carried on the developing roller 25.

[0023] The toner supplied to the developing roller 25 passes through the developing blade 27 (restricting member) as the developing roller 25 rotates counterclockwise and is thinned (coated) to an appropriate layer thickness. Also, at this time, the toner supplied to the developing roller 25 is triboelectrically charged to a negative polarity by rubbing against the surface of the developing blade 27.

[0024] Then, the toner coated on the developing roller 25 is conveyed to the developing nip where the photosensitive drum 1 and the developing roller 25 face each other. Due to the electrostatic latent image potential formed on the photosensitive drum 1 by the exposure device 3 and the electric field formed by the developing bias (developing voltage) applied from a developing power source (not shown) to the developing roller 25, a part of the toner coated on the developing roller 25 transfers to the photosensitive drum 1 at the developing nip. In this way, the electrostatic latent image is developed (visualized) into a toner image by attaching toner charged with the same polarity as the charging polarity of the photosensitive drum 1 to the exposed portion on the photosensitive drum 1 (inversion development method). That is, the developing roller 25 as the developing member forms a toner image on the photosensitive drum 1 by supplying toner to the photosensitive drum 1.

[0025] The toner remaining on the developing roller 25 without being used for development at the developing nip is scraped off by the rotating toner supply roller 26 at the contact portion between the developing roller 25 and the toner supply roller 26. At the same time, the toner stored in the vicinity of the contact portion between the developing roller 25 and the toner supply roller 26 is newly supplied onto the developing roller 25.

[0026] The toner image formed on the photosensitive drum 1 is transferred to a recording material P such as paper by the action of a transfer roller 5 as a transfer member. The transfer roller 5 is biased (pressed) toward the photosensitive drum 1 by a transfer pressure spring which is a biasing member (not shown), and thus is in pressure contact with the photosensitive drum 1. Thereby, a transfer nip portion which is a contact portion between the photosensitive drum 1 and the transfer roller 5 is formed. The transfer nip portion sandwiches and conveys the recording material P.

[0027] The transfer roller 5 rotates in a driven manner following the rotation of the photosensitive drum 1. In this embodiment, the outer diameter of the transfer roller 5 is 14.0 mm. The transfer roller 5 sandwiches and conveys the recording material P together with the photosensitive drum 1. At this time, a transfer bias (transfer voltage), which is a DC voltage having a polarity opposite to the charging polarity (normal charging polarity) of the toner during development, is applied to the transfer roller 5 from a transfer power source (high-voltage power source) (not shown). Thereby, the toner image on the photosensitive drum 1 is transferred to a predetermined position on the recording material P. Transfer residual toner of the formed image remains on the photosensitive drum 1 after transfer, and is recovered by a cleaning device 6.

[0028] The cleaning device 6 is provided with a cleaning blade 29 as a cleaning member, and the cleaning blade 29 has a support sheet metal and a rubber portion having elasticity fixed to the tip of the support sheet metal. By the tip of the rubber portion provided on the free end side of the cleaning blade 29 abutting against the photosensitive drum 1 in the counter direction, the cleaning blade 29 can remove the transfer residual toner remaining on the photosensitive drum 1. Further, the cleaning device 6 is provided with a space (waste toner container) capable of storing the recovered waste toner.

[0029] The recording material cassette 7 is loaded with the recording material P, and the recording material P is fed by a pickup roller 8. Then, the recording material P fed by the pickup roller 8 is sent out one by one by a separation nip portion formed by a feed roller 9 and a retard roller 10.

[0030] Further, the recording material P is conveyed at a predetermined timing by the pair of conveyance rollers 11 and the pair of resist rollers 12, guided by the pre-transfer upper guide 15 and the pre-transfer lower guide 16, and reaches the transfer nip portion. At the transfer nip portion, an image is formed on the recording material P by transferring the toner image onto the recording material P.

[0031] Next, the operation of the image forming apparatus A after an image is formed on the recording material P will be described. The amount of charge formed on the surface of the recording material P onto which the toner image has been transferred at the transfer nip portion due to the application of the transfer voltage is reduced by the charge removing needle 17. Thereafter, the recording material P is guided by the conveyance guide 18 and the pre-fixing guide 32 and conveyed to the fixing device 20. An adsorption sheet metal 19 is disposed on the conveyance guide 18, and by exerting a force to attract the charged recording material P, the recording material P can be conveyed more stably.

[0032] The fixing device 20 as a fixing unit has a heating roller 30 and a pressure roller 31. The heating roller 30 as a fixing member is rotatably supported by the frame of the fixing device 20 and is rotationally driven by a drive source (not shown). The pressure roller 31 is pressed against the heating roller 30 by a fixing pressure spring which is an urging member (not shown). Thereby, the heating roller 30 and the pressure roller 31 come into contact with each other to form a fixing nip portion. The heating roller 30 can be heated by a heat source (not shown). A thermistor 34 is attached to the heating roller 30, and the temperature of the heating roller 30 is controlled based on the detection result of the thermistor 34. The recording material P is nipped and conveyed while being heated at the fixing nip portion.

[0033] The unfixed toner image formed on the recording material P is melted by being heated and pressed by the fixing device 20 and fixed as a fixed image on the surface of the recording material P. The recording material P on which the toner image has been fixed by the fixing device 20 is discharged onto a discharge tray 23 provided on the upper surface of the apparatus main body M by the pair of discharge rollers 22. Further, the image forming apparatus A can confirm the occurrence of a jam (paper jam) or the like by detecting the leading end and the trailing end of the recording material P with the top sensor 14 and the discharge sensor 21.

[0034] In addition, the image forming apparatus A is provided with an exhaust fan 50 and an exhaust duct 51, which will be described later. The air passage formed by the exhaust duct 51 is disposed between the cleaning device 6 and the fixing device 20. Therefore, the heat generated in the fixing device 20 and the image forming unit 150 can be efficiently exhausted. Details of the air flow will be described later.

[0035] [Air Flow] The air flow in the image forming apparatus A in this embodiment will be described. FIG. 2 is a front view of the image forming apparatus A according to the first embodiment, and FIG. 3 is a perspective view of the image forming apparatus A according to the first embodiment. However, for the sake of explanation, both FIGS. 2 and 3 are shown with the components near the discharge roller pair 22 and the discharge tray 23 removed.

[0036] As shown in FIGS. 2 and 3, the main body frame 43 is composed of a right side plate 40, a left side plate 41, and a scanner stay 42. The right side plate 40 and the left side plate 41 are connected by the scanner stay 42. The main body frame 43 is a structure that constitutes the skeleton of the image forming apparatus A and has substantially the same width as the overall width of the image forming apparatus A in the width direction W orthogonal to the conveyance direction CD of the recording material P.

[0037] The scanner stay 42 as a support member supports the exposure device 3 that irradiates the photosensitive drum 1 with laser light. The fixing device 20 is attached to the main body frame 43 of the image forming apparatus A and is fixed by fixing screws (not shown). Therefore, in maintenance or the like, the fixing device 20 can be detached from the main body frame 43 of the image forming apparatus A by removing the fixing screws (not shown).

[0038] The exhaust fan 50 is fixed to the right side plate 40 at a position corresponding to the position between the cleaning device 6 and the fixing device 20, and is a fan having an outer dimension of 60 [mm] × 60 [mm]. That is, the exhaust fan 50 is disposed on one side of the exhaust duct 51 in the width direction W. Further, the exhaust fan 50 has a function of discharging the air inside the image forming apparatus A to the outside of the apparatus. Hereinafter, the side of the right side plate 40 inside the main body frame 43 is referred to as the drive side, and the surface of the right side plate 40 to which the exhaust fan 50 is attached is referred to as the drive side surface. This is the right side surface when viewed from the front surface of the image forming apparatus A (the upstream side in the conveyance direction CD of the recording material P during image formation). Conversely, the left side, that is, the side of the left side plate 41 when viewed from the front surface of the image forming apparatus A is referred to as the electrical equipment side, and the left side surface of the left side plate 41 is referred to as the electrical equipment side surface.

[0039] The exhaust duct 51 as a duct is disposed at the center of the image forming apparatus A in the width direction W at a position corresponding to the position between the cleaning device 6 and the fixing device 20. The exhaust duct 51 is attached to the scanner stay 42. The exhaust duct 51 is disposed so that air can pass from the electrical equipment side to the drive side, thereby forming an air passage for discharging the air on the electrical equipment side to the outside of the apparatus. The detailed function of the exhaust duct 51 will be described later.

[0040] Next, the heat source of the image forming apparatus A and the corresponding air flow will be described. The developing device 4, the cleaning device 6, and the exposure device 3 of the image forming unit 150 generate heat during the image generation operation. Further, since the fixing device 20 has a heating element, it generates heat during heating. Regarding this heat generation, the generated heat can be discharged to the outside of the apparatus by the exhaust of the exhaust fan 50.

[0041] FIG. 4 is a left side view of the image forming apparatus A according to the first embodiment. As shown in FIG. 4, a low-voltage power supply 45, a control board 46, and an image signal generation board 47 are attached to the left side plate 41. The low-voltage power supply 45 is disposed at the lower part of the surface on the electrical equipment side of the left side plate 41, and the low-voltage power supply 45 appropriately converts the AC voltage supplied from the inlet and supplies the power required for the image generation operation including driving and heating. The control board 46 is disposed at the upper front side of the surface on the electrical equipment side of the left side plate 41. The control board 46 includes a control unit (not shown) and a high-voltage unit (not shown). The control unit controls the image signal generation board 47 and the entire image forming apparatus A. The high-voltage unit is a generation unit for voltages required for image formation including the charging power supply, the developing power supply, and the transfer power supply described above. The image signal generation board 47 is a generation unit for a VDO signal modulated corresponding to the time-series electrical digital pixel signal of the print data (image information) input from a host computer (not shown). The exposure device 3 controls the ON / OFF of light emission based on the VDO signal. These low-voltage power supply 45, control board 46, and image signal generation board 47 generate heat due to loss during use in the image forming operation.

[0042] FIG. 5 is a perspective view near the main body frame 43 according to the first embodiment, and is a view in which the components of the fixing device 20, the low-voltage power supply 45, the control board 46, and the image signal generation board 47 are further removed from FIG. 3. FIG. 5 also shows the main body frame 43, the conveyance guide 18, the suction sheet metal 19, the exposure device 3, and the exhaust heat duct 51.

[0043] As shown in FIG. 5, a ventilation port 52 is provided in the left side plate 41, and the ventilation port 52 is located at a position corresponding to the electrical equipment side of the exhaust heat duct 51. Heat generated from the electrical equipment side such as the low-voltage power supply 45 can be discharged through the ventilation port 52 and the exhaust heat duct 51 by the exhaust of the exhaust heat fan 50. Due to the air flow described above, heat generated at various locations during the image forming operation can be discharged well without being trapped inside the image forming apparatus A.

[0044] [Exhaust heat duct] The exhaust duct 51 in this embodiment is characterized by forming an air passage AP that connects from the electrical equipment side to the drive side and efficiently suppressing the transmission of the exhaust heat of the fixing device 20 to the cleaning device 6.

[0045] FIG. 6 is a schematic cross-sectional view near the exhaust duct 51 according to Embodiment 1. As shown in FIG. 6, the exhaust duct 51 is disposed near the fixing cover 33 of the fixing device 20 and near the cleaning device 6. First, the fixing cover 33 will be described. The fixing cover 33 is disposed near the heating roller 30 and covers the heating roller 30. The fixing cover 33 prevents the user from touching the heating roller 30 in a high-temperature state and suppresses damage to the heating roller 30 caused by the user touching the heating roller 30. The fixing cover 33 is made of a resin material excellent in heat resistance and electrical insulation, such as polycarbonate, for example.

[0046] In this embodiment, the center of the exhaust fan 50 is on the upper surface side and the front side of the apparatus main body M with respect to the center of the fixing device 20. And the exhaust duct 51 is disposed so as to overlap the exhaust fan 50 as a fan when viewed in the width direction W. Further, the exhaust duct 51 is disposed on the same side as the container 6a of the cleaning device 6 with respect to the conveyance path P10 described later.

[0047] Also, it is characterized in that the shape of the front side of the fixing cover 33 extends from the upper surface side toward the lower surface side. Specifically, a flat portion B is formed on the front side of the fixing cover 33, and the flat portion B has an angle of 71° with respect to the horizontal plane. This is to efficiently transfer the heat of the fixing device 20 to the exhaust duct 51 while preventing it from being transferred to the cleaning device 6. Details of the operation and effect will be described later.

[0048] Here, a conveyance path P10 through which the sheet passes is formed between the transfer roller 5 and the fixing device 20. In other words, the conveyance path P10 is a conveyance path through which the sheet passes between the transfer nip portion and the fixing nip portion. Further, the first wall portion C of the exhaust heat duct 51 that is close to the flat portion B of the fixing cover 33 has a first end portion C1 closest to the conveyance path P10 and a second end portion C2 closest to the conveyance path P10. The second end portion C2 is connected to the upper surface 51a.

[0049] And the distance between the flat portion B of the fixing cover 33 and the portion of the first wall portion C of the exhaust heat duct 51 that is close to the flat portion B of the fixing cover 33 is 3.0 mm or less. More specifically, the distance between the flat portion B and the first end portion C1 of the first wall portion C, which is the closest portion, is 1.5 mm, and the distance between the flat portion B and the second end portion C2 of the first wall portion C, which is the farthest portion, is 2.5 mm. Further, by disposing the exhaust heat duct 51 composed of a metal plate (metal material) between the fixing device 20 and the cleaning device 6, the heat of the fixing device 20 is suppressed from directly being transmitted to the cleaning device 6. The cleaning device 6 has a container 6a for accommodating the transferred residual toner, and the container 6a has a surface 6b facing and close to the exhaust heat duct 51. That is, the container 6a as the toner collection container collects the toner removed from the surface of the photosensitive drum 1 by the cleaning blade 29. The distance between the second wall portion D of the exhaust heat duct 51 that is close to the surface 6b of the container 6a of the cleaning device 6 and the surface 6b is 2.0 mm. Further, the second wall portion D extends to a position closer to the conveyance path P10 than the cleaning blade 29 when viewed in the width direction W.

[0050] As described above, a pre-fixing guide 32 is provided on the side opposite to the cleaning device 6 with respect to the conveyance path P10. The pre-fixing guide 32 as a guide member is disposed so as to overlap the fixing device 20 in the conveyance direction CD, and guides the recording material P toward the fixing nip portion of the fixing device 20. And the exhaust heat duct 51 is disposed so as to overlap the pre-fixing guide 32 in the conveyance direction CD.

[0051] FIG. 7(a) is a perspective view of the exhaust duct 51 according to the first embodiment, and FIG. 7(b) is a front view of the exhaust duct 51. FIG. 7(c) is a plan view of the exhaust duct 51, and FIG. 7(d) is a side view of the exhaust duct 51.

[0052] As shown in FIGS. 7(a) to 7(d), the exhaust duct 51 extends such that the width direction W is the longitudinal direction. The exhaust duct 51 has a first wall portion C facing the flat portion B of the fixing cover 33, a second wall portion D facing the cleaning device 6, and an upper surface 51a connecting the first wall portion C and the second wall portion D. In other words, the exhaust duct 51 has a first wall portion C facing the fixing device 20, a second wall portion D facing the container 6a, and an upper surface 51a. The upper surface 51a is provided with attachment portions 54a and 54b and a positioning portion 54c.

[0053] The exhaust duct 51 is configured to be slidably attached to the scanner stage 42 of the main body frame 43 in the thrust direction (width direction W). By sliding and attaching the exhaust duct 51 to the scanner stage 42, the positioning portion 54c abuts against the abutting portion of the scanner stage 42, and the exhaust duct 51 is positioned with respect to the scanner stage 42. In this state, the attachment portions 54a and 54b are screwed to the scanner stage 42 with fixing screws, and the exhaust duct 51 is fixed to the scanner stage 42.

[0054] The second wall portion D provided on the front side of the exhaust duct 51 and adjacent to the cleaning device 6 has a length of 32 mm in a cross section orthogonal to the width direction W. Further, in the present embodiment, the upper surface 51a extends in the horizontal direction, and the angle θ1 formed between the second wall portion D of the exhaust duct 51 and the upper surface 51a is 90°. That is, the second wall portion D extends in the vertical direction. And, on the back side of the exhaust duct 51, the length of the first wall portion C adjacent to the fixing cover 33 in a cross section orthogonal to the width direction W is 30 mm. The angle θ2 formed between the first wall portion C of the exhaust duct 51 and the upper surface 51a is 75°. That is, the first wall portion C extends linearly in a direction intersecting the vertical direction when viewed in the width direction W parallel to the rotation axis direction of the photosensitive drum 1. The width direction W can also be said to be the rotation axis direction of the photosensitive drum 1.

[0055] That is, the first wall portion C is inclined with respect to the second wall portion D. More specifically, the first wall portion C is inclined with respect to the second wall portion D such that the distance between the first end portion C1 of the first wall portion C and the second wall portion D is shorter than the distance between the second end portion C2 of the first wall portion C and the second wall portion D.

[0056] [Operation and Effect of Example 1] The operation and effect of the present embodiment will be described. In the present embodiment, the flat portion B of the fixing cover 33 is formed in a shape inclined from the vertical (vertical direction, gravity direction), and the first wall portion C of the exhaust duct 51 is arranged in proximity to the flat portion B. Thereby, while exhausting more heat of the fixing device 20, by increasing the amount of air flowing in the exhaust duct 51, the heat transmitted to the cleaning device 6 can be further reduced.

[0057] The flat portion B as the facing surface of the fixing cover 33 faces the first wall portion C and extends along the first wall portion C. That is, by arranging the flat portion B of the fixing cover 33 in proximity to the exhaust duct 51, the heat of the fixing cover 33 heated by the heating roller 30 can be efficiently applied to the exhaust duct 51. Further, in the present embodiment, the first wall portion C of the exhaust duct 51 is shaped so as to lie down more than perpendicular (vertical direction, gravitational direction) along the flat portion B. Thereby, the portion of the air passage AP formed by the exhaust duct 51 that overlaps with the fins 50a of the exhaust fan 50 (that is, the space where heat can be exhausted by the exhaust fan 50) can be made larger, and the heat of the exhaust duct 51 can be further reduced.

[0058] In recent years, in an image forming apparatus, the calorific value of a fixing device has increased for improving productivity, and a cleaning device and a fixing device tend to be arranged close to each other for miniaturization. However, when the cleaning device is heated by the heat of the fixing device, the residual transfer toner accommodated inside the cleaning device may aggregate. When the residual transfer toner aggregates in the cleaning device, there is a risk that the residual transfer toner removed from the photosensitive drum by the cleaning blade may leak out of the cleaning device.

[0059] By configuring the fixing cover 33 and the exhaust duct 51 as in the present embodiment, it is possible to suppress the temperature rise of the cleaning device 6 and to prevent the residual transfer toner from aggregating or leaking out of the cleaning device 6.

[0060] Next, a secondary effect will be described. Here, the thermistor 34 that detects the temperature of the heating roller 30 has a pedestal 34a attached to the fixing cover 33, an arm portion 34b extending downward from the pedestal 34a, and a temperature detection portion 34c provided in the pedestal 34a. The arm portion 34b is provided so as to be elastically deformable so that it can stably contact the heating roller 30. The arm portion 34b is connected to the temperature detection portion 34c so as to be heat-transferable. In the present embodiment, the temperature detection portion 34c is provided in the pedestal 34a, but the present invention is not limited to this, and the temperature detection portion 34c may be provided outside the pedestal 34a.

[0061] In this way, although the thermistor 34 can detect the temperature of the heating roller 30, there is a problem that the detected temperature slightly deviates due to the temperature in the vicinity of the heating roller 30, particularly the temperature of the fixing cover 33. This is because the heat transfer state to the temperature detection unit 34c changes due to the change in the ambient temperature around the pedestal 34a of the thermistor 34, the arm portion 34b, and the like.

[0062] For example, even when the temperature of the heating roller 30 is under the same conditions, if the ambient temperature around the fixing cover 33, the pedestal 34a of the thermistor 34, the arm portion 34b, and the temperature detection unit 34c increases, the heat outflow in the heat transfer path to the temperature detection unit 34c decreases, and the detected temperature of the thermistor 34 becomes slightly higher. This means that the detected temperature of the thermistor 34 for the optimal fixing of the toner image to the recording material P changes between the state where the fixing cover 33 is cold and the state where it is warmed up. This leads to a reduction in the margin for the problems that occur when the temperature of the heating roller 30 is high and the problems that occur when it is low. For example, when the temperature of the heating roller 30 is high, there is a possibility that the recording material P may be wound around the heating roller 30, resulting in paper jams, and when the temperature of the heating roller 30 is low, there is a possibility that the toner image may not be sufficiently fixed to the recording material P.

[0063] As in this embodiment, by forming the flat portion B of the fixing cover 33 in a shape that is more reclined than vertical and arranging the first wall portion C of the exhaust duct 51 in proximity to the flat portion B, the amount of temperature change of the fixing cover 33 depending on the usage state of the image forming apparatus A can be reduced. As a result, it is possible to suppress the occurrence of the recording material P being wound around the heating roller 30 and fixing defects (blister images or cold offset) due to insufficient fixing temperature accompanying the usage state of the image forming apparatus A.

[0064] [Verification of the Effect of Example 1] Next, the results of the image output experiment for verifying the effects of this embodiment will be described. The image output experiment was conducted for this embodiment and Comparative Examples 1 and 2. FIG. 8(a) is a perspective view showing the exhaust duct 2151 according to Comparative Example 1, and FIG. 8(b) is a front view showing the exhaust duct 2151. FIG. 8(c) is a plan view showing the exhaust duct 2151, and FIG. 8(d) is a side view showing the exhaust duct 2151. As shown in FIGS. 8(a) to 8(d), the angle formed by the upper surface 2151a of the exhaust duct 2151 and the first wall portion C is 90°, and the length in the cross section orthogonal to the width direction W of the first wall portion C is 30 mm. Also, the angle formed by the upper surface 2151a and the second wall portion D is 90°, and the length in the cross section orthogonal to the width direction W of the second wall portion D is 32 mm. Further, the distance at the closest part between the flat portion B of the fixing cover 33 and the first wall portion C is 1.5 mm, and the distance at the farthest part is 4.0 mm.

[0065] FIG. 9(a) is a perspective view showing the exhaust duct 2251 according to Comparative Example 2, and FIG. 9(b) is a front view showing the exhaust duct 2251. FIG. 9(c) is a plan view showing the exhaust duct 2251, and FIG. 9(d) is a side view showing the exhaust duct 2251. As shown in FIGS. 9(a) to 9(d), the angle formed by the upper surface 2251a of the exhaust duct 2251 and the first wall portion C is 75°, and the length in the cross section orthogonal to the width direction W of the first wall portion C is 30 mm. Also, the angle formed by the upper surface 2251a and the second wall portion D is 75°, and the length in the cross section orthogonal to the width direction W of the second wall portion D is 32 mm. Further, the distance at the closest part between the flat portion B of the fixing cover 33 and the first wall portion C is 1.5 mm, and the distance at the farthest part is 2.5 mm.

[0066] Table 1 shows the summarized results of the configurations of the above-described this embodiment and Comparative Examples 1 and 2.

Table 1

[0067] First, the image output experiment of "toner leakage" will be described. The evaluation experiment of toner leakage will be explained. For the recording material P, Canon Red Label (Canon E.U., product name) with a basis weight of 80 g / m2 and a paper size of A4 was used.

[0068] In the image forming apparatus used in the experiment, the process speed at this time was 280 mm / sec, and the throughput was 50 images per minute. Also, the set temperature of the fixing device 20 was 200°C. Note that the experiment was conducted in an ambient environment of a temperature of 32.5°C and a humidity of 80%.

[0069] With the image forming apparatus left powered off overnight to confirm that the internal temperature was sufficiently close to the ambient environment, after printing 10,000 sheets (20,000 images) of a horizontal line image with a printing rate of 2% in double-sided continuous printing, it was checked whether toner leakage occurred from the cleaning device 6 inside the image forming apparatus.

[0070] Also, in order to quantify the effect of the experimental results, thermocouples were brought into contact with the flat portion B of the fixing cover 33, the first wall portion C, and the second wall portion D to measure the respective maximum temperatures reached during printing.

[0071] In the image forming apparatuses of this example and Comparative Examples 1 and 2, the results of the image output experiment of "toner leakage" and the temperatures measured in the evaluation experiment are shown in Table 2.

Table 2

[0072] In this example, in the evaluation experiment of toner leakage, no toner leakage occurred. On the other hand, in Comparative Example 1, toner leakage occurred. Also, in Comparative Example 2, toner leakage occurred.

[0073] Next, the obtained effects will be described based on the temperature results measured in the toner leakage evaluation experiment. In this embodiment, by arranging the first wall portion C of the exhaust duct 51 in proximity to the flat portion B of the fixing cover 33, while exhausting more heat from the fixing device 20, and by increasing the amount of air flowing in the exhaust duct 51, the heat transmitted to the cleaning device 6 can be further reduced.

[0074] On the other hand, in Comparative Example 1, the flat portion B of the fixing cover 33 and the first wall portion C of the exhaust duct 2151 are not in proximity as compared to this embodiment. Also, in Comparative Example 1, the space (air passage) in the exhaust duct 2151 is narrower as compared to this embodiment. When comparing this embodiment with Comparative Example 1, the temperature difference between the reaching temperature of the fixing cover 33 and the reaching temperature of the first wall portion C is 14.5 °C (= 65 °C - 50.5 °C) in this embodiment, which is lower than 17 °C (= 71 °C - 54 °C) in Comparative Example 1. This is because in this embodiment, the flat portion B of the fixing cover 33 and the first wall portion C of the exhaust duct 51 are in proximity, so that the heat of the fixing device 20 can be more absorbed by the exhaust duct 51.

[0075] Also, the temperature difference between the first wall portion C and the second wall portion D is 5 °C (= 50.5 °C - 45.5 °C) in this embodiment and 3 °C (= 54 °C - 51 °C) in Comparative Example 1, and the 2 °C difference can be increased because in this embodiment, the amount of air flowing in the exhaust duct 51 can be increased, so that the heat of the exhaust duct 51 can be more exhausted.

[0076] On the other hand, in Comparative Example 2, the flat portion B of the fixing cover 33 and the first wall portion C of the exhaust duct 2251 are in proximity in the same manner as this embodiment. The temperature difference between the reaching temperature of the fixing cover 33 and the reaching temperature of the first wall portion C is 14.5 °C (= 65 °C - 50.5 °C) in this embodiment, which is approximately the same as 15 °C (= 71.5 °C - 65 °C) in Comparative Example 2.

[0077] However, in Comparative Example 2, compared with Example 1, the air volume flowing in the exhaust duct 2251 cannot be increased. For this reason, while the temperature of the second wall portion D was 45.5°C in this Example, it has become as high as 53°C. This is because the exhaust duct 2251 that absorbs the temperature of the fixing device 20 due to the fixing cover 33 and the exhaust duct 2251 being close to each other cannot take in the air volume, and thus heat has been transmitted to the vicinity of the cleaning device 6.

[0078] In such an image output experiment in which the exhaust heat state is like this, in Comparative Examples 1 and 2, the reaching temperature of the second wall portion D is high compared to this Example where the reaching temperature of the second wall portion D is low. Therefore, the transferred residual toner in the cleaning device 6 aggregates. Then, the transferred residual toner in the cleaning device 6 stacks up, and it is considered that toner leakage has occurred because the transferred residual toner has leaked out of the cleaning device 6.

[0079] Next, the image output experiments of "poor fixing" and "wrapping" will be described. Similar to the previous experiment, the process speed of the image forming apparatus is 280 mm / sec and the throughput is 50 images per minute. The set temperatures of the fixing device 20 are two temperature settings of 200°C and 195°C. Incidentally, the experiment was conducted in an ambient environment of temperature 23°C and humidity 50%.

[0080] First, the evaluation experiment of poor fixing will be described. For the recording material P, Hammermill Premium Color Copy 60lb. Cover Paper (Hammermill, product name) with a basis weight of 162 g / m2 and a paper size of LTR was used.

[0081] With the image forming apparatus left powered off overnight, after confirming that the internal temperature of the apparatus was sufficiently close to the ambient environment temperature, after printing 550 sheets (550 images) of a solid black image with a printing rate of 100% in single-sided continuous printing, it was checked whether poor fixing had occurred in the printed image.

[0082] Next, the winding evaluation experiment will be described. For the recording material P, CS-060F (Canon Marketing Japan, product name) with a basis weight of 60 g / m2 and a paper size of A4 was used. After leaving the image forming apparatus powered off overnight to confirm that the temperature inside was sufficiently close to the ambient environment temperature, during the printing of 550 sheets (1100 images) of a full black image with a printing rate of 100% in double-sided continuous printing, it was checked whether a paper jamming phenomenon occurred where the recording material wound around the fixing device 20.

[0083] In the image forming apparatuses of this Example and Comparative Examples 1 and 2, Table 3 shows the set temperature of the fixing device 20 and the results of each evaluation experiment.

Table 3

[0084] In this Example, in the evaluation experiments of fixing failure and winding, when the set temperature was 200°C, although there was no occurrence of fixing failure, winding occurred. When the temperature was 195°C, neither fixing failure nor winding occurred.

[0085] On the other hand, in Comparative Example 1, fixing failure occurred at a set temperature of 195°C, and winding occurred at a set temperature of 200°C. Also, in Comparative Example 2, fixing failure occurred at a set temperature of 195°C, and winding occurred at a set temperature of 200°C.

[0086] Next, the obtained operational effects will be described based on the temperature results measured in the toner leakage evaluation experiment. The effects of the invention regarding exhaust heat are the same in the image output experiments of "fixing failure" and "winding".

[0087] As described in the image output experiment of the above-mentioned "toner leakage", the reaching temperature of the fixing cover 33 is high in Comparative Examples 1 and 2 as compared with this Example in which the reaching temperature of the fixing cover 33 is low. When the reaching temperature of the fixing cover 33 is high, the detected temperature of the thermistor 34 becomes high. Therefore, when the temperature of the heating roller 30 is controlled to be the same detected temperature in such a state, the temperature of the heating roller 30 becomes low.

[0088] In the image output experiment of Comparative Examples 1 and 2 in such an exhaust heat state, when the set temperature is 195 ° C, it is considered that the temperature of the heating roller 30 has dropped to a level where fixing failure occurs at a low temperature ripple temperature associated with the temperature control of the heating roller 30.

[0089] In order to suppress the occurrence of fixing failure in Comparative Examples 1 and 2, when the set temperature of the fixing device 20 is increased to 200 ° C, when the temperature of the fixing cover 33 is low, the adverse effects when the fixing temperature is too high occur. That is, in this Example, although a temperature setting that can achieve both non-occurrence of fixing failure and non-occurrence of winding can be achieved by setting the temperature to 195 ° C, Comparative Examples 1 and 2 cannot achieve this compatibility.

[0090] As described above, by forming the flat portion B of the fixing cover 33 into a shape that is laid down rather than vertical and arranging the first wall portion C of the exhaust duct 51 in proximity to the flat portion B, while exhausting more heat from the fixing device 20, The amount of air flowing in the exhaust duct 51 can be increased. For this reason, the heat transmitted from the fixing device 20 or the like to the cleaning device 6 can be further reduced, and the heat can be exhausted in a small size and efficiently. In other words, the heat insulation performance of the heat from the fixing device 20 can be improved.

[0091] <Example 2> Next, Example 2 of the present invention will be described. Example 2 uses an exhaust duct 151 corresponding to the shape of the fixing cover 133 different from that of Example 1. For this reason, for the same configuration as in Example 1, illustration is omitted or the same reference numerals are given in the drawings for explanation.

[0092] FIG. 10 is a schematic cross-sectional view near the exhaust duct 151 according to Example 2. As shown in FIG. 10, the fixing cover 133 has an arc portion 133a located upstream of the heating roller 30 in the conveyance direction CD of the recording material P. The fixing cover 133 is made of a resin material excellent in heat resistance and electrical insulation such as polycarbonate, for example. The arc portion 133a is disposed at a position approximately uniformly separated from the heating roller 30 by 4 mm so as to cover the surface of the heating roller 30. Further, the exhaust duct 151 as a duct has an arc portion 151a located upstream of the fixing cover 133 in the conveyance direction CD and a second wall portion D. The arc portion 151a as the first wall portion is disposed at a position approximately uniformly separated from the arc portion 133a of the fixing cover 133 by 1.5 mm so as to cover the arc portion 133a of the fixing cover 133. That is, the arc portion 133a as the opposing surface faces the arc portion 151a and extends along the arc portion 151a.

[0093] Further, the arc portion 151a is formed to be curved when viewed in the width direction W parallel to the rotation axis direction of the photosensitive drum 1. That is, the arc portion 151a is inclined with respect to the second wall portion D.

[0094] FIG. 11(a) is a perspective view of the exhaust duct 151 according to Example 2, FIG. 11(b) is a front view of the exhaust duct 151, FIG. 11(c) is a plan view of the exhaust duct 151, and FIG. 11(d) is a side view of the exhaust duct 1151. The effects in this embodiment are the same as those in Example 1, and it is possible to suppress the aggregation of the transfer residual toner accommodated inside the cleaning device 6 due to the heat generated in the fixing device 20 and the leakage of the transfer residual toner from the cleaning device 6. This is because the arc portion 151a of the exhaust duct 151 is arranged in proximity to the arc portion 133a of the fixing cover 133. Thereby, while exhausting more heat from the fixing device 20, by increasing the amount of air flowing in the exhaust duct 151, the heat transmitted to the cleaning device 6 can be further reduced.

[0095] Also, the secondary effects are the same as those in Example 1, and it is possible to suppress the winding of the recording material P accompanying the use state of the image forming apparatus A and the occurrence of fixing defects (blister images or cold offset) due to insufficient fixing temperature. This is due to the effect that by arranging the arc portion 151a of the exhaust duct 151 in proximity to the arc portion 133a of the fixing cover 133, the amount of temperature change of the fixing cover 133 due to the use state of the image forming apparatus A can be reduced.

[0096] Regarding these effects, compared with Example 1, since the amount of air flowing in the exhaust duct 151 can be made larger, a greater effect can be obtained. On the other hand, the shape of the exhaust duct 151 becomes more complicated.

[0097] As described above, in this embodiment, by using the exhaust duct 151 corresponding to the shape of the fixing cover 133 different from that in Example 1, the same effects as those in Example 1 can be effectively obtained.

[0098] <Example 3> Next, Example 3 of the present invention will be described. Example 3 uses an exhaust duct 251 with further improved exhaust efficiency compared to Example 1. For this reason, for the same configurations as those in Example 1, the illustration is omitted or the same reference numerals are given in the drawings for explanation.

[0099] FIG. 12 is a schematic cross-sectional view near the exhaust duct 251 according to Example 3. FIG. 13(a) is a perspective view showing the exhaust duct 251 according to Example 3, FIG. 13(b) is a front view showing the exhaust duct 251, FIG. 13(c) is a plan view showing the exhaust duct 251, and FIG. 13(d) is a side view showing the exhaust duct 251. FIG. 14(a) is a perspective view showing a state in which the exhaust fins 53 according to Example 3 are assembled to the main body portion 251e of the exhaust duct 251, and FIG. 14(b) is a side view showing a state in which the exhaust fins 53 are assembled to the main body portion 251e of the exhaust duct 251.

[0100] As shown in FIGS. 13(a) to 14(b), a plurality (three in this embodiment) of elongated holes 251b extending in the width direction W and arranged side by side in the vertical direction are provided in the main body portion 251e of the exhaust duct 251 as a duct. The main body portion 251e as the first member has the same shape as the exhaust duct 51 of the first embodiment except for the elongated holes 251b, and forms an air passage AP. The exhaust duct 251 is configured by assembling the exhaust fins 53 as the second member to the main body portion 251e.

[0101] The exhaust fins 53 are made of a galvanized steel sheet which is a metal material and are formed in a substantially V-shaped cross section, and have an upper surface 53a and side surfaces 53b that are bent and extend downward from the upper surface 53a. The side surface 53b as the first wall portion faces the fixing device 20. A plurality (three in this embodiment) of protrusions 53c protruding toward the upstream side in the transport direction CD are provided on the side surface 53b. In other words, the plurality of protrusions 53c protrude toward the air passage AP. Further, the plurality of protrusions 53c extend in a direction intersecting the width direction W which is the longitudinal direction of the exhaust duct 251. Each protrusion 53c extends in the width direction W so as to correspond to the elongated hole 251b.

[0102] As described above, the exhaust fins 53 are assembled to the scanner stage 42 after the main body portion 251e is slid in the thrust direction (width direction W) to the scanner stage 42 of the main body frame 43. At this time, as shown in FIG. 12, the main body portion 251e and the exhaust fins 53 sandwich the scanner stage 42. In this state, the main body portion 251e and the exhaust fins 53 are fixed to the scanner stage 42 by fixing screws. At this time, the protrusions 53c of the exhaust fins 53 penetrate through the elongated holes 251b and protrude into the internal space of the exhaust duct 251.

[0103] This exhaust heat fin 53 is designed to enhance the exhaust heat efficiency by increasing the surface area of the member that comes into contact with the air flowing within the exhaust duct 251. In other words, the multiple protruding portions 53c of the exhaust heat fin 53 are uneven shapes for increasing the surface area of the member that comes into contact with the air flowing through the air passage AP within the exhaust duct 251. As a result, the contact area with the air of the exhaust duct 251 can be increased, improving the cooling effect. Consequently, the heat of the fixing device 20 can be more effectively exhausted, and the heat transferred to the cleaning device 6 can be further reduced.

[0104] The effects in this embodiment are the same as those in Embodiment 1. Heat generated by the fixing device 20 can suppress the aggregation of residual transfer toner stored inside the cleaning device 6 and prevent the residual transfer toner from leaking out of the cleaning device 6.

[0105] Also, the secondary effects are the same as those in Embodiment 1. It is possible to suppress the occurrence of P-wrapping of the recording material associated with the usage state of the image forming apparatus A and fixing defects (blister images or cold offset) due to insufficient fixing temperature.

[0106] Regarding these effects, compared with Embodiment 1, since the exhaust heat by the air flowing in the exhaust duct 251 can be made more effective, a greater effect can be obtained. On the other hand, because the exhaust heat fin 53 is attached to the main body portion 251e, the shape becomes more complex.

[0107] As described above, in this embodiment, it is possible to provide an exhaust duct 251 with even higher exhaust heat efficiency compared to Embodiment 1. In other words, the heat insulation performance of the heat from the fixing device 20 can be improved.

[0108] <Embodiment 4> Next, Embodiment 4 of the present invention will be described. Embodiment 4 uses an exhaust duct 351 with even higher exhaust heat efficiency compared to Embodiment 1. Therefore, for the same configurations as in Embodiment 1, the illustration will be omitted or the same reference numerals will be used in the figures for explanation.

[0109] FIG. 15 is a schematic cross-sectional view near the exhaust duct 351 according to Example 4. FIG. 16(a) is a perspective view showing the exhaust duct 351 according to Example 4, FIG. 16(b) is a front view showing the exhaust duct 351, FIG. 16(c) is a plan view showing the exhaust duct 351, and FIG. 16(d) is a side view showing the exhaust duct 351.

[0110] As shown in FIGS. 15 to 16(d), the exhaust duct 351 as a duct has a first wall portion C, a second wall portion D, and a partition wall 351f disposed between the first wall portion C and the second wall portion D. And the exhaust duct 351 is configured to obtain two spaces (air passages) for flowing air in the exhaust duct 351. That is, the exhaust duct 351 is bent so as to form a first air passage SP1 on the downstream side in the conveyance direction CD as the sheet conveyance direction, that is, near the fixing device 20, and a second air passage SP2 on the upstream side in the conveyance direction CD, that is, near the cleaning device 6. In other words, the partition wall 351f of the exhaust duct 351 divides the air passage AP into a first air passage SP1 formed between the first wall portion C and a second air passage SP2 formed between the second wall portion D.

[0111] The exhaust duct 351 is assembled to the scanner stage 42, and the second air passage SP2 is a space surrounded by the scanner stage 42 and the exhaust duct 351. The air generated by the exhaust fan 50 passes through the first air passage SP1 and the second air passage SP2.

[0112] With such a configuration, by increasing the length of the exhaust duct 351 from the fixing cover 33 side to the cleaning device 6 side of the exhaust duct 351, an effect of increasing the temperature difference can be obtained. Further, by dividing the air flowing in the exhaust duct 351 into two, even if the temperature of the air flowing through the first air passage SP1 near the fixing cover 33 rises due to exhaust heat, the air flowing through the second air passage SP2 near the cleaning device 6 is less likely to be heated. Thereby, the heat of the fixing device 20 can be exhausted more, and the heat transmitted to the cleaning device 6 can be reduced more.

[0113] Regarding the effects in this embodiment, they are the same as those in Embodiment 1. Heat generated by the fixing device 20 can suppress aggregation of the residual transfer toner accommodated inside the cleaning device 6 and leakage of the residual transfer toner from the cleaning device 6.

[0114] Also, regarding the secondary effects, they are the same as those in Embodiment 1. Generation of winding of the recording material P and fixing defects (blister images or cold offset) due to insufficient fixing temperature associated with the usage state of the image forming apparatus A can be suppressed.

[0115] Regarding these effects, compared with Embodiment 1, since the exhaust heat by the wind flowing in the exhaust duct 351 can be made more effective, a greater effect can be obtained. On the other hand, since the first air passage SP1 and the second air passage SP2 are formed by the exhaust duct 351, the shape becomes more complicated.

[0116] As described above, in this embodiment, an exhaust duct 351 with further improved exhaust heat efficiency can be provided with respect to Embodiment 1. In other words, the heat insulation performance of the heat from the fixing device 20 can be improved.

[0117] <Example 5> Next, Example 5 of the present invention will be described. Example 5 is obtained by changing the shape of the first wall portion C of the exhaust duct 51 in Example 1. For this reason, regarding the same configuration as that in Example 1, illustration is omitted or the same reference numerals are given in the drawings for explanation.

[0118] FIG. 17(a) is a perspective view showing an exhaust duct 451 according to Example 5, FIG. 17(b) is a front view showing the exhaust duct 451, FIG. 17(c) is a plan view showing the exhaust duct 451, and FIG. 17(d) is a side view showing the exhaust duct 451.

[0119] As shown in FIGS. 17(a) to (d), the first wall portion C of the exhaust heat duct 451 as the duct according to Example 5 is configured to be bent along the shape of the fixing cover 33 shown in FIG. 6. That is, the first wall portion C is configured to face the fixing cover 33 and be disposed at a position substantially equally spaced from the plane portion B of the fixing cover 33. Thereby, as in Example 2, a larger amount of air can flow into the exhaust heat duct 451. Therefore, the same effects as in Examples 1 and 2 can be achieved.

[0120] <Example 6> Next, Example 6 of the present invention will be described. In Example 6, a protruding portion 551b is provided on the exhaust heat duct 551 instead of the exhaust heat fins 53 of Example 3. For this reason, regarding the same configuration as in Example 3, illustration is omitted or the same reference numerals are given in the drawings for explanation.

[0121] FIG. 18(a) is a perspective view showing the exhaust heat duct 551 according to Example 6, and FIG. 18(b) is a front view showing the exhaust heat duct 551. FIG. 18(c) is a plan view showing the exhaust heat duct 551, and FIG. 18(d) is a side view showing the exhaust heat duct 551.

[0122] As shown in FIGS. 18(a) to (d), the exhaust heat duct 551 as a duct made of a metal material is provided with a plurality (three in this embodiment) of protruding portions 551b protruding toward the internal space of the exhaust heat duct 551. The protruding portion 551b is formed by drawing the downstream surface of the exhaust heat duct 551 in the conveying direction CD and extends in the width direction W. The protruding portion 551b can increase the surface area of the member with which the air flowing in the exhaust heat duct 551 comes into contact, like the exhaust heat fins 53 of Example 3. Therefore, the same effects as in Example 3 can be achieved.

[0123] <Example 7> Next, Example 7 of the present invention will be described. In Example 7, instead of the exhaust heat fin 53 of Example 3, an exhaust heat fin 653 is provided on the upstream side in the conveyance direction CD of the main body portion 651e. Therefore, for the same configurations as those in Example 3, illustration will be omitted or the same reference numerals will be given in the drawings for explanation.

[0124] FIG. 19(a) is a perspective view showing the exhaust heat duct 651 according to Example 7, FIG. 19(b) is a front view showing the exhaust heat duct 651, FIG. 19(c) is a plan view showing the exhaust heat duct 651, and FIG. 19(d) is a side view showing the exhaust heat duct 651. FIG. 20(a) is a perspective view showing a state where the exhaust heat fin 653 according to Example 7 is assembled to the main body portion 651e, and FIG. 20(b) is a side view showing a state where the exhaust heat fin 653 is assembled to the main body portion 651e. By assembling the exhaust heat fin 653 to the main body portion 651e, the exhaust heat duct 651 as a duct is configured.

[0125] As shown in FIGS. 19(a) to 20(b), a plurality (three in the present embodiment) of elongated holes 651b extending in the width direction W and arranged in parallel in the vertical direction are provided in the main body portion 651e of the exhaust heat duct 651. The main body portion 651e as the first member has the same shape as the exhaust heat duct 51 of Example 1 except for the elongated holes 651b. The exhaust heat fin 653 as the second member is composed of a galvanized steel sheet which is a metal material. A plurality (three in the present embodiment) of protruding portions 653c protruding toward the downstream side in the conveyance direction CD are provided from the side surface of the exhaust heat fin 653. Each protruding portion 653c extends in the width direction W so as to correspond to the elongated hole 651b.

[0126] As described above, after the main body portion 651e is slid in the thrust direction (width direction W) to the scanner stage 42 of the main body frame 43 and attached, the exhaust heat fin 653 is assembled to the scanner stage 42. At this time, the exhaust heat fin 653 is attached to the main body portion 651e from the upstream side in the conveyance direction CD. At this time, the protruding portion 653c of the exhaust heat fin 653 penetrates the elongated hole 651b and protrudes into the internal space of the exhaust heat duct 651.

[0127] This exhaust heat fin 653, similar to those in Embodiments 3 and 6, is configured to enhance the efficiency of exhaust heat by increasing the surface area of the member that comes into contact with the air flowing within the exhaust duct 651. Thus, it can achieve the same effects as those in Embodiments 3 and 6.

[0128] In this embodiment, the protruding portion 653c is provided on the side of the surface (the second wall portion) facing the cleaning device 6 of the exhaust duct 651. In Embodiment 3, the protruding portion 53c was provided on the side of the surface (the first wall portion) facing the fixing device 20 of the exhaust duct 651. That is, a plurality of protruding portions protruding toward the air passage AP may be provided on at least one of the first wall portion and the second wall portion of the exhaust duct.

[0129] <Embodiment 8> Next, Embodiment 8 of the present invention will be described. In Embodiment 8, a protruding portion 751b is provided on the exhaust duct 751 instead of the protruding portion 551b in Embodiment 6. For this reason, for the same configurations as those in Embodiment 6, the illustration will be omitted or the same reference numerals will be used in the drawings for explanation.

[0130] FIG. 21(a) is a perspective view showing the exhaust duct 751 according to Embodiment 8, FIG. 21(b) is a front view showing the exhaust duct 751, FIG. 21(c) is a plan view showing the exhaust duct 751, and FIG. 21(d) is a side view showing the exhaust duct 751.

[0131] As shown in FIGS. 21(a) to 21(d), the exhaust heat duct 751 as a duct made of a metal material is provided with a plurality (three in this embodiment) of protrusions 751b protruding toward the internal space of the exhaust heat duct 751. The protrusion 751b is formed by drawing the upstream surface of the exhaust heat duct 751 in the transport direction CD and extends in the width direction W. The protrusion 751b can increase the surface area of the member with which the air flowing in the exhaust heat duct 751 comes into contact, like the exhaust heat fins 53 of Example 3. In other words, the plurality of protrusions 751b of the exhaust heat duct 751 are uneven shapes for increasing the surface area of the member with which the air flowing in the air passage AP in the exhaust heat duct 751 comes into contact. Thereby, the contact area of the exhaust heat duct 751 with air can be increased and the cooling effect can be improved. Therefore, the same effects as in Examples 3 and 6 can be achieved.

[0132] <Example 9> Next, Example 9 of the present invention will be described. In Example 9, an exhaust heat duct 851 composed of two members is provided instead of the exhaust heat duct 351 of Example 4. For this reason, regarding the same configuration as in Example 4, illustration is omitted or the same reference numerals are given in the drawings for explanation.

[0133] FIG. 22(a) is a perspective view showing the exhaust heat duct 851 according to Example 9, and FIG. 22(b) is a front view showing the exhaust heat duct 851. FIG. 22(c) is a plan view showing the exhaust heat duct 851, and FIG. 22(d) is a side view showing the exhaust heat duct 851.

[0134] As shown in FIGS. 22(a) to 22(d), the exhaust heat duct 851 as a duct according to Example 9 has a first member 851a and a second member 851b. The first member 851a and the second member 851b are assembled to each other and fixed integrally by fixing screws or the like. The first member 851a has a first wall portion C facing the fixing device 20. The second member 851b has a second wall portion D facing the cleaning device 6 and a partition wall 851f.

[0135] The exhaust duct 851 is configured to obtain two spaces (air passages) for flowing air in the exhaust duct 851. That is, the exhaust duct 851 is bent so as to form a first air passage SP1 on the downstream side in the conveyance direction CD, that is, close to the fixing device 20, and a second air passage SP2 on the upstream side in the conveyance direction CD, that is, close to the cleaning device 6. In other words, the partition wall 851f of the second member 851b divides the air passage AP into a first air passage SP1 formed between the first wall portion C and a second air passage SP2 formed between the second wall portion D.

[0136] As a result, although there is a demerit that two members are required, there is a merit that two spaces for flowing air in the exhaust duct 851 can be formed into a more sealed shape (less escape of air passing through the exhaust duct 851). Therefore, the same effect as in the fourth embodiment can be achieved.

[0137] Regarding the fifth to ninth embodiments described above, while exhausting more heat from the fixing device 20, the heat transmitted to the cleaning device 6 can be further reduced by the air flowing in the exhaust duct, and the exhaust heat can be performed in a small size and efficiently. That is, the heat insulation performance of the heat from the fixing device 20 can be improved.

[0138] <Embodiment 10> Next, the tenth embodiment of the present invention will be described. The tenth embodiment is configured to improve the conveyance performance of the recording material P as compared with the first embodiment. For this reason, regarding the same configuration as in the first embodiment, illustration is omitted or the same reference numerals are given in the drawings and described. Regarding the configuration of the image forming apparatus according to the tenth embodiment, the positional relationship among the exhaust duct, the pre-fixing guide 32, and the fixing cover is different from that in the first embodiment, and the rest is the same as in the first embodiment. Therefore, the description of the overlapping part with the configuration of the first embodiment is omitted.

[0139] [Exhaust Duct] FIG. 23 is a schematic cross-sectional view near the exhaust heat duct 951 according to Example 10. The exhaust heat duct 951 in this example has a different positional relationship between the first wall portion C close to the flat portion B of the fixing cover 933 in the exhaust heat duct 951 and the flat portion B of the fixing cover 933 from that in Example 1.

[0140] In this example, as shown in FIG. 23, the first wall portion C close to the flat portion B of the fixing cover 933 in the exhaust heat duct 951 has an end portion 951d that is a free end. Also, the flat portion B of the fixing cover 933 has an end portion 933d that is a free end. The end portion 933d is the upstream end of the fixing cover 933 in the conveyance direction CD. And the first wall portion C is arranged so as not to straddle a straight line LN1 that passes through the end portion 933d and extends in the vertical direction. That is, the end portion 951d of the first wall portion C is arranged downstream of the straight line LN1 in the conveyance direction CD.

[0141] The distance between the flat portion B of the fixing cover 933 and the first wall portion C close to the flat portion B of the fixing cover 933 in the exhaust heat duct 951 is 3.0 mm or less. More specifically, the distance at the closest portion between the flat portion B and the first wall portion C is 1.0 mm, and the distance at the farthest portion is 2.5 mm. Also, by arranging the exhaust heat duct 951 composed of a metal plate at the boundary with the cleaning device 6, the heat of the fixing device 20 is suppressed from being directly transmitted to the cleaning device 6. Among the exhaust heat duct 951, the distance between the second wall portion D close to the surface 6b of the container 6a of the cleaning device 6 and the surface 6b is 2.0 mm.

[0142] [Operation and Effect of Example 10] The operation and effects of this embodiment will be described. In this embodiment, the first wall portion C of the exhaust duct 951 is configured not to straddle the straight line LN1 passing through the end portion 933d of the flat portion B. That is, directly below the end portion 951d of the first wall portion C of the exhaust duct 951, the flat portion B of the fixing cover 933 extends. In other words, between the conveyance path P10 between the transfer nip portion and the fixing nip portion and the end portion 951d of the first wall portion C of the exhaust duct 951, the flat portion B of the fixing cover 933 is interposed, and the end portion 951d does not directly face the conveyance path P10. The fixing cover 933 is made of a resin material excellent in electrical insulation, such as polycarbonate. Thereby, it is possible to obtain stable conveyance performance without causing problems such as paper wrinkles without being affected by the electrostatic adsorption force exerted by the recording material P on the exhaust duct 951 as a duct.

[0143] This is related to the fact that the recording material P is charged by being supplied with charges from the transfer roller 5 when passing through the transfer roller 5. When an object grounded is brought close to the charged recording material P, an electrostatic adsorption force acts on the recording material P with respect to the object. However, even if the exhaust duct 951 in this embodiment is configured to be grounded to the main body frame 43 via the scanner stay 42, since the first wall portion C of the exhaust duct 951 is arranged not to straddle the straight line LN1, an effect of suppressing the generation of an electrostatic adsorption force on the recording material P with respect to the exhaust duct 951 can be obtained.

[0144] [Effect Confirmation of Example 10] Next, in order to confirm the effects of this embodiment, the results of the conveyance performance experiment of the recording material P will be described. For the effect confirmation, the exhaust duct 951 of this embodiment and the exhaust duct 51 of Example 1 as a comparative example were used.

[0145] The method of the conveyance performance experiment of the recording material P will be described. As the recording material, standard paper CS-068 (Canon Marketing Japan, trade name) with a basis weight of 68 g / m2 and a paper size of A4 was used.

[0146] In the image forming apparatus used in the experiment, the process speed at this time was 280 mm / sec, and the throughput was 50 images per minute. Also, the set temperature of the fixing device was 200°C. Note that the experiment was conducted in an ambient environment of temperature 15°C and humidity 10%.

[0147] From the state where the image forming apparatus and the recording material P were left in the above ambient environment for two nights, the occurrence situation of paper wrinkles was confirmed when 200 sheets of the recording material were continuously printed by single-sided continuous printing. The results obtained from the conveyance performance experiment of the recording material P are shown in Table 4.

Table 4

[0148] When the exhaust heat duct 951 in this example was used, no paper wrinkles occurred in the recording material P, and the results were good. On the other hand, when the exhaust heat duct 951 of Example 1 was used, paper wrinkles occurred in the recording material P. That is, by using the exhaust heat duct 951 of this example, the conveyance performance of the recording material P could be improved, and the occurrence of paper wrinkles could be suppressed.

[0149] As described above, by arranging the first wall portion C of the exhaust heat duct 951 so as not to straddle the straight line LN1, the influence of the electrostatic adsorption force exerted by the recording material P on the exhaust heat duct 951 can be suppressed. Thereby, while improving the heat insulation performance of the heat from the fixing device 20, conveyance failures such as paper wrinkles can be suppressed, and the conveyance property can be improved.

[0150] <Example 11> Next, Example 11 of the present invention will be described. Example 11 is obtained by changing the shapes of the fixing cover 933 and the exhaust heat duct 951 of Example 10. Therefore, for the same configuration as in Example 3, illustration is omitted or the same reference numerals are given in the drawings for explanation.

[0151] [Exhaust Heat Duct and Fixing Cover] FIG. 24 is a schematic cross-sectional view near the exhaust duct 1051 according to Embodiment 11. As shown in FIG. 24, the angle formed between the first wall portion C of the exhaust duct 1051 and the upper surface 1051a is 90°. The flat portion B of the fixing cover 1033 in the present embodiment is bent, and the vicinity of the end portion 1033d extends upstream in the conveyance direction CD. In other words, the flat portion B is arranged to cover the end portion 1051d of the first wall portion C of the exhaust duct 1051 as a duct. The fixing cover 1033 is made of a resin material excellent in electrical insulation such as polycarbonate, for example. Even with the configuration as in the present embodiment, the influence of the electrostatic adsorption force exerted by the recording material P on the exhaust duct 1051 can be suppressed. Thereby, while improving the heat insulation performance of the heat from the fixing device 20, conveyance failures such as paper wrinkles can be suppressed, and the conveyance performance can be improved.

[0152] <Example 12> Next, Example 12 of the present invention will be described. Example 12 is configured to suppress the temperature rise of the exposure device 3 as compared with Example 1. For this reason, for the same configurations as in Example 1, illustration is omitted or the same reference numerals are given in the drawings for explanation. FIG. 25 is a schematic cross-sectional view of the image forming apparatus A according to Example 12.

[0153] As shown in FIG. 25, the scanner stage 42 supports the exposure device 3 that irradiates the photosensitive drum 1 with laser light. Further, the exhaust duct 1151 as a duct is attached to the scanner stage 42 so as to be slid in the thrust direction (width direction W). That is, the exhaust heat of the fixing device 20 taken into the exhaust duct 1151 may flow to the exposure device 3 through the scanner stage 42. In this case, when the exposure device 3 is heated, a normal exposure operation may not be performed, such as the accuracy of the exposure image not meeting the standard.

[0154] Note that the scanner stage 42 in this embodiment is part of the main body frame 43 and is made of a metal material such as zinc-coated steel plate to obtain high rigidity. When the scanner stage 42 is made of a metal material with a higher thermal conductivity than resin in this way, the amount of heat flowing from the exhaust heat duct 1151 to the exposure apparatus 3 also increases.

[0155] [Exhaust Heat Duct] The exhaust heat duct 1151 in this embodiment is characterized by suppressing the heat flowing to the scanner stage 42 when discharging the exhaust heat of the fixing device 20 to the outside of the machine. The exhaust heat duct 1151 in this embodiment is attached to the scanner stage 42 with a heat insulating member 55 interposed therebetween.

[0156] FIG. 26(a) is a perspective view showing the exhaust heat duct 1151 according to Embodiment 12, FIG. 26(b) is a front view showing the exhaust heat duct 1151, FIG. 26(c) is a plan view showing the exhaust heat duct 1151, and FIG. 26(d) is a side view showing the exhaust heat duct 1151.

[0157] As shown in FIGS. 26(a) to (d), the heat insulating member 55 in this embodiment uses polycarbonate with a relatively low thermal conductivity and is attached to the exhaust heat duct 1151 using double-sided tape. The heat insulating member 55 has a lower thermal conductivity than the exhaust heat duct 1151 made of a metal material. Polycarbonate is a kind of resin material, and the heat insulating member 55 may be made of a resin material other than polycarbonate. The heat insulating member 55 extends in the width direction W, and it is preferably longer in the width direction W as long as the attachment of the exhaust heat duct 1151 to the scanner stage 42 is not hindered. In this embodiment, NS5000 (manufactured by Nitto Denko Corporation, product name) is used as the double-sided tape. Further, the exhaust heat duct 1151 to which the heat insulating member 55 is attached is attached to the scanner stage 42 using screws.

[0158] [Operation and Effect of Embodiment 12] The operation and effect of this embodiment will be described. As in this embodiment, by disposing the heat insulating member 55 between the exhaust heat duct 1151 and the scanner stage 42, heat transfer from the exhaust heat duct 1151 to the scanner stage 42 can be suppressed.

[0159] In addition, by disposing a heat insulating member between the scanner stage 42 and the exposure apparatus 3, an effect of suppressing the temperature rise of the exposure apparatus 3 can also be obtained. However, when the temperature of the scanner stage 42 rises, the ambient temperature in the vicinity of the exposure apparatus 3 may rise, which may cause the temperature of the exposure apparatus 3 to rise. Therefore, the configuration for suppressing heat transfer from the exhaust heat duct 1151 to the scanner stage 42 as in this embodiment has a higher effect of suppressing the temperature rise of the exposure apparatus 3.

[0160] [Effect confirmation of Example 12] Next, in order to confirm the effect of this embodiment, the results of the temperature rise experiment of the exposure apparatus 3 will be described. For the effect confirmation, the exhaust heat duct 1151 of this embodiment and the exhaust heat duct 1151 of Example 1 as a comparative example were used.

[0161] Details of the method of the temperature rise experiment will be described. As the recording material, Canon Red Label (Canon E.U., product name) with a basis weight of 80 g / m2 and a paper size of A4 was used. In the image forming apparatus used in the experiment, the process speed at this time was 280 mm / sec and the throughput was 50 images per minute. Also, the set temperature of the fixing device 20 was 200°C. The experiment was conducted in an ambient environment of a temperature of 32.5°C and a humidity of 80%.

[0162] The image forming apparatus A was left overnight with the power turned off, and after confirming that the internal temperature was sufficiently close to the ambient environment, a horizontal line image with a printing rate of 2% was printed continuously on both sides 500 sheets (1000 images), and then the surface temperature of the scanner stage 42 and the surface temperature of the exposure apparatus 3 were confirmed. Thermocouples were brought into contact with the mounting portion for mounting the exposure apparatus 3 of the scanner stage 42 and the polygon motor portion of the exposure apparatus 3, and the maximum temperature reached was measured respectively.

[0163] Table 5 shows the results of summarizing the temperatures measured by the temperature increase experiment.

Table 5

[0164] When the exhaust heat duct 1151 in this embodiment was used, the surface temperature of the scanner stage 42 was 40°C, and the surface temperature of the exposure apparatus 3 was 55°C. On the other hand, when the exhaust heat duct 1151 of Example 1 was used, the surface temperature of the scanner stage 42 was 45°C, and the surface temperature of the exposure apparatus 3 was 60°C. That is, by using the exhaust heat duct 1151 of this embodiment, the temperature increase of the scanner stage 42 could be suppressed, and furthermore, the temperature increase of the exposure apparatus 3 could be suppressed.

[0165] As described above, by disposing the heat insulating member 55 between the exhaust heat duct 1151 and the scanner stage 42, heat transfer from the exhaust heat duct 1151 to the scanner stage 42 can be suppressed, and the temperature increase of the exposure apparatus 3 can be suppressed. In other words, the heat insulation performance of the heat from the fixing device 20 can be improved.

[0166] <Example 13> Next, Example 13 of the present invention will be described. Example 13 is configured to suppress the temperature increase of the exposure apparatus 3 with a simple configuration as compared with Example 12. For this reason, the same configurations as those in Example 12 will be described with illustration omitted or the same reference numerals in the drawings.

[0167] FIG. 27 is a schematic cross-sectional view of the image forming apparatus A according to Embodiment 13. As shown in FIG. 27, the exhaust heat duct 1251 in the present embodiment is characterized by being made of a resin material having a lower thermal conductivity than a metal material. FIG. 28(a) is a perspective view showing the exhaust heat duct 1251 according to Embodiment 13, FIG. 28(b) is a front view showing the exhaust heat duct 1251, FIG. 28(c) is a plan view showing the exhaust heat duct 1251, and FIG. 28(d) is a side view showing the exhaust heat duct 1251. Note that the shape of the exhaust heat duct 1251 may be any of the shapes described in the above-described embodiments.

[0168] In the above-described Embodiment 12, the exhaust heat duct 1251 and the scanner stage 42 are made of a metal material having a high thermal conductivity. Therefore, by disposing a heat insulating member 55 having a low thermal conductivity between the exhaust heat duct 1251 and the scanner stage 42, heat transfer from the exhaust heat duct 1251 to the scanner stage 42 is suppressed, and the temperature rise of the exposure apparatus 3 is suppressed.

[0169] In the present embodiment, the exhaust heat duct 1251 is made of a resin material having a lower thermal conductivity than the scanner stage 42 made of a metal material. Thereby, the temperature rise of the exposure apparatus 3 can be suppressed. However, by making the exhaust heat duct 1251 of a resin material, the effect of absorbing the heat of the fixing device 20 by the exhaust heat duct 1251 and exhausting the heat by the air flowing through it is reduced. Further, the scanner stage 42 is a part of the main body frame 43, and it is preferable to be made of a metal material such as a zinc-coated steel plate in order to ensure high rigidity.

[0170] As described above, in the present embodiment, by configuring the exhaust heat duct 1251 as a duct with a material having a low thermal conductivity, the temperature rise of the exposure apparatus 3 is suppressed. Thereby, it is not necessary to dispose the heat insulating member 55 between the exhaust heat duct 1251 and the scanner stage 42, and the temperature rise of the exposure apparatus 3 can be suppressed with a simple configuration. In other words, the heat insulation performance of the heat from the fixing device 20 can be improved.

[0171] If the rigidity can be ensured, the scanner stage 42 may be made of a resin material with low thermal conductivity, or the exhaust heat duct 1251 and the scanner stage 42 may be made of a resin material with low thermal conductivity.

[0172] <Example 14> Next, Example 14 of the present invention will be described. Example 14 is configured to be able to more efficiently take in the exhaust heat of the fixing device 20 compared to Example 1. For this reason, for the same configurations as those in Example 1, illustration will be omitted or the same reference numerals will be given in the drawings and explanation will be made.

[0173] FIG. 29 is a schematic cross-sectional view near the exhaust heat duct 1351 according to Example 14. FIG. 30(a) is a front view showing the exhaust heat duct 1351 according to Example 14, FIG. 30(b) is a plan view showing the exhaust heat duct 1351, and FIG. 30(c) is a side view showing the exhaust heat duct 1351. FIG. 31(a) is a perspective view showing the exhaust heat duct 1351 according to Example 14, and FIG. 31(b) is another perspective view showing the exhaust heat duct 1351.

[0174] As shown in FIGS. 29 to 31(b), a plurality (three in this embodiment) of duct vents 56 are provided in the first wall portion C of the exhaust heat duct 1351 as a duct, which faces the fixing cover 33. These duct vents 56 as a plurality of openings extend in the width direction W, are arranged side by side in the vertical direction, and communicate with the air passage AP. Through this duct vent 56, the exhaust heat from the fixing device 20 can be efficiently taken into the exhaust heat duct 1351, and the exhaust heat of the fixing device 20 can be efficiently discharged outside the machine.

[0175] Regarding the duct vent 56 provided in the first wall portion C of the exhaust heat duct 1351, as the size of the opening, the area ratio of the duct vent 56 is 19% with respect to the first wall portion C. In terms of obtaining the effects of this embodiment, it is desirable that the area ratio of the duct vent 56 is 3% or more. The larger the area ratio of the duct vent 56, the more effective it is to efficiently discharge the exhaust heat from the fixing device 20 outside the machine.

[0176] As a result, by efficiently discharging the exhaust heat from the fixing device 20 to the outside of the machine, the temperature rise inside the machine can be suppressed. That is, by suppressing the temperature rise inside the machine, the temperature rise of the cleaning device 6 and the exposure device 3 can be suppressed.

[0177] In addition, due to the fact that the detection temperature for the optimal fixing of the toner image on the recording material P by the thermistor 34 changes between the state where the fixing cover 33 is cold and the state where it is warmed up as described in Example 1, the margin for the problems that occur when the temperature of the heating roller 30 is high and the problems that occur when it is low can also be increased.

[0178] While increasing the exhaust heat from the fixing device 20, the discharge of heat generated from the low-voltage power supply 45 through the ventilation port 52 and the exhaust duct 1351 due to the exhaust of the exhaust fan 50 is in a decreasing direction. Therefore, it is desirable that the area ratio of the duct ventilation port 56 to the first wall portion C is less than 60%. This opening ratio can be adjusted according to the characteristics of the image forming apparatus, such as the degree of exhaust heat from the fixing device 20 described above, by adjusting the size of the duct ventilation port 56 (that is, the opening ratio of the first wall portion C).

[0179] As described above, by providing the duct ventilation port 56 in the exhaust duct 1351, the exhaust heat of the fixing device 20 can be more efficiently taken into the exhaust duct 1351, and the temperature rise of the cleaning device 6 and the exposure device 3 can be suppressed. In other words, the heat insulation performance of the heat from the fixing device 20 can be improved.

[0180] In addition, in this embodiment, the duct ventilation port 56 as a plurality of openings is provided only in the first wall portion C, but it is not limited to this. For example, the duct ventilation port 56 may be provided in the second wall portion D, or may be provided in both the first wall portion C and the second wall portion D. That is, the duct ventilation port 56 may be provided in at least one of the first wall portion C and the second wall portion D.

[0181] <Example 15> Next, Example 15 of the present invention will be described. Example 15 is configured to suppress the temperature rise of the cleaning device 6 as compared with Example 1. For this reason, for the same configurations as those in Example 1, illustration will be omitted or the same reference numerals will be used in the drawings for explanation.

[0182] When the printing speed is further increased compared to the image forming apparatus of Example 1, the calorific value generated by the fixing device 20 becomes larger. The cleaning device 6, which is close to the fixing device 20 and self-heats due to friction with the photosensitive drum 1, is likely to have its temperature rise.

[0183] [Exhaust duct] The exhaust duct 1451 as a duct in this embodiment is characterized in that it suppresses the heat flowing to the cleaning device 6 when discharging the exhaust heat of the fixing device 20 to the outside of the machine. Similar to Example 1, the exhaust duct 1451 in this embodiment forms an air passage connecting from the electrical equipment side to the driving side, and efficiently suppresses the exhaust heat of the fixing device 20 from being transmitted to the cleaning device 6. Further, a heat insulating member 155 is provided on the second wall portion D of the exhaust duct 1451 close to the cleaning device 6, and heat transfer to the cleaning device 6 can be suppressed.

[0184] FIG. 32 is a schematic cross-sectional view of the vicinity of the exhaust duct 1451 according to Example 15. As shown in FIG. 32, a heat insulating member 155 is attached to the second wall portion D of the exhaust duct 1451 in this embodiment. FIG. 33(a) is a perspective view showing the exhaust duct 1451 and the heat insulating member 155 according to Example 15, FIG. 33(b) is a front view showing the exhaust duct 1451 and the heat insulating member 155, FIG. 33(c) is a plan view showing the exhaust duct 1451 and the heat insulating member 155, and FIG. 33(d) is a side view showing the exhaust duct 1451 and the heat insulating member 55.

[0185] In this embodiment, the heat insulating member 155 is made of polycarbonate, which is a resin material, and is attached to the exhaust heat duct 1451 so as to be slid in the thrust direction (width direction W). In other words, the heat insulating member 155 has lower thermal conductivity than the exhaust heat duct 1451 made of a metal material. Further, the exhaust heat duct 1451 to which the heat insulating member 155 is attached is attached to the scanner stage 42 using screws.

[0186] [Operation and Effect of Embodiment 15] The operation and effect of this embodiment will be described. As in this embodiment, by disposing the heat insulating member 155 on the second wall portion D of the exhaust heat duct 1451, heat transfer from the exhaust heat duct 1451 to the cleaning device 6 can be suppressed.

[0187] [Effect Confirmation of Embodiment 15] Next, in order to confirm the effect of this embodiment, the results of the temperature rise experiment of the exposure apparatus 3 will be described. For the effect confirmation, the exhaust heat duct 1451 of this embodiment and the exhaust heat duct 1451 of Embodiment 1 as a comparative example were used.

[0188] Details of the method of the temperature rise experiment will be described. As the recording material, Canon Red Label (Canon E.U., product name) with a basis weight of 80 g / m2 and a paper size of A4 was used.

[0189] In the image forming apparatus used in the experiment, the process speed at this time was 320 mm / sec and the throughput was 55 images per minute. Further, the set temperature of the fixing device was 215°C. The experiment was conducted in an ambient environment of temperature 32.5°C and humidity 80%.

[0190] With the image forming apparatus left turned off overnight to confirm that the internal temperature was sufficiently close to the ambient environment, after printing 500 sheets (1000 images) of a horizontal line image with a printing rate of 2% in double-sided continuous printing, the surface temperature of the cleaning device 6 facing the exhaust heat duct 1451 was measured.

[0191] Table 6 shows the results of summarizing the temperatures measured by the temperature increase experiment.

Table 6

[0192] When the exhaust duct 1451 in this example was used, the surface temperature of the cleaning device 6 was 44°C. On the other hand, when the exhaust duct 1451 of Example 1 was used, the surface temperature of the cleaning device 6 was 47°C. That is, by using the exhaust duct 1451 of this example, the temperature increase of the cleaning device 6 could be suppressed.

[0193] As described above, by providing the heat insulating member 155 on the second wall portion D close to the cleaning device 6 of the exhaust duct 1451, the temperature increase of the cleaning device 6 can be further suppressed. In other words, the heat insulation performance of the heat from the fixing device 20 can be improved.

[0194] <Example 16> Next, Example 16 of the present invention will be described. Example 16 is configured to suppress the temperature increase of the cleaning device 6 and the exposure device 3 as compared with Example 1. Therefore, for the same configuration as in Example 1, illustration will be omitted or the same reference numerals will be given in the drawings for explanation.

[0195] When the printing speed is increased, the heat generation amount of the fixing device 20 becomes larger. As a result, for example, the amount of heat exhausted to the exhaust duct 51 in Example 1 may become too large, and the influence of the temperature increase of the cleaning device 6 and the exposure device 3 may become too large. In such a case, by arranging the heat insulating member 255 on the fixing cover side of the exhaust duct 51, the temperature increase of the cleaning device 6 and the exposure device 3 can be further suppressed.

[0196] FIG. 34 is a schematic cross-sectional view near the exhaust heat duct 51 according to Example 16. As shown in FIG. 34, a heat insulating member 255 is attached to the first wall portion C close to the fixing device 20 of the exhaust heat duct 51 in this example. FIG. 35(a) is a perspective view showing the exhaust heat duct 51 and the heat insulating member 255 according to Example 16, FIG. 35(b) is a front view showing the exhaust heat duct 51, FIG. 35(c) is a plan view showing the exhaust heat duct 51 and the heat insulating member 255, and FIG. 35(d) is a side view showing the exhaust heat duct 51 and the heat insulating member 255.

[0197] The heat insulating member 255 in this example uses polycarbonate, which is a resin material with a relatively low thermal conductivity, and is attached to the exhaust heat duct 51 by sliding in the thrust direction (width direction W). In other words, the heat insulating member 255 has lower thermal conductivity than the exhaust heat duct 51 made of a metal material. Further, the exhaust heat duct 51 to which the heat insulating member 255 is attached is attached to the scanner stage 42 using screws.

[0198] By reducing the amount of exhaust heat from the fixing device 20 to the exhaust heat duct 51, the exhaust heat of the fixing device 20 itself is reduced, and the temperature rise of the cleaning device 6 and the exposure device 3 can be suppressed. On the other hand, in terms of the secondary effect described in Example 1, it is in a decreasing direction, and the configuration is such that the reaching temperature of the fixing cover 33 becomes high. From this, in terms of good temperature control of the heating roller 30 in the state where the reaching temperature of the fixing cover 33 is low and high, that is, in the state where the detected temperature of the thermistor 34 is high and low, it is in an unfavorable direction.

[0199] As described above, by disposing the heat insulating member 255 on the first wall portion C close to the fixing cover 33 of the exhaust heat duct 51, the exhaust heat of the fixing device 20 by the exhaust heat duct 51 can be reduced, and the temperature rise of the cleaning device 6 and the exposure device 3 can be suppressed. In other words, the heat insulation performance of the heat from the fixing device 20 can be improved.

[0200] In Example 15, the heat insulating member 155 was attached to the second wall portion D, and in Example 16, the heat insulating member 255 was attached to the first wall portion C. And these heat insulating members 155 and 255 may be attached to the first wall portion C and the second wall portion D. That is, a heat insulating member having a lower thermal conductivity than the exhaust heat duct may be provided on at least one of the first wall portion C and the second wall portion D of the exhaust heat duct.

[0201] <Example 17> Next, Example 17 of the present invention will be described. Example 17 is different from Example 10 in that the shape of the exhaust heat duct 951 is deformed. For this reason, for the same configurations as those in Example 10, illustration is omitted or the same reference numerals are given in the drawings for explanation.

[0202] FIG. 36 shows a schematic cross-sectional view near the exhaust heat duct 1651 according to Example 17. FIG. 37(a) is a perspective view showing the exhaust heat duct 1651 according to Example 17, FIG. 37(b) is a front view showing the exhaust heat duct 1651, FIG. 37(c) is a plan view showing the exhaust heat duct 1651, and FIG. 37(d) is a side view showing the exhaust heat duct 1651.

[0203] The exhaust heat duct 1651 as the duct of this example is configured to shorten the length of the first wall portion C close to the fixing device 20 with respect to the shape of the exhaust heat duct 51 of Example 1. The fixing cover 1633 is made of a resin material excellent in electrical insulation such as polycarbonate, for example. Thereby, similar to Example 10, it is possible to obtain stable transportability without causing problems such as paper wrinkles without being affected by the electrostatic adsorption force acting on the recording material P with respect to the exhaust heat duct 1651.

[0204] That is, in this embodiment, as shown in FIG. 36, the first wall portion C of the exhaust heat duct 1651 that is close to the flat portion B of the fixing cover 1633 is arranged so as not to cross the straight line LN1 that passes through the end portion 1633d of the flat portion B and extends in the vertical direction. That is, the end portion 1651d of the first wall portion C is arranged downstream in the conveyance direction CD from the straight line LN1. In other words, the flat portion B is arranged so as to cover the end portion 1651d of the first wall portion C of the exhaust heat duct 1651. Therefore, the same effects as those of Embodiments 10 and 11 can be achieved.

[0205] <Embodiment 18> Next, Embodiment 18 of the present invention will be described. Embodiment 18 has a modified shape of the exhaust heat duct 1151 as compared with Embodiment 12. For this reason, for the same configurations as those in Embodiment 12, illustration will be omitted or the same reference numerals will be given in the drawings for explanation.

[0206] FIG. 38 shows a schematic cross-sectional view near the exhaust heat duct 2151 according to Embodiment 18. FIG. 39(a) is a perspective view showing the exhaust heat duct 2151 and the heat insulating member 55 according to Embodiment 18, FIG. 39(b) is a front view showing the exhaust heat duct 2151, FIG. 39(c) is a plan view showing the exhaust heat duct 2151 and the heat insulating member 55, and FIG. 39(d) is a side view showing the exhaust heat duct 2151 and the heat insulating member 55.

[0207] As shown in FIGS. 38 to 39(d), the exhaust heat duct 2151 according to this embodiment has the same shape as the exhaust heat duct of Comparative Example 1 shown in FIGS. 8(a) to (d). And the same heat insulating member 55 as that in Embodiment 12 is assembled to the upper surface 2151a of the exhaust heat duct 2151.

[0208] The exhaust duct 2151 is attached to the scanner stage 42 with a heat insulating member 55 sandwiched between the exhaust duct 2151 and the scanner stage 42. Thereby, heat transfer from the exhaust duct 2151 to the scanner stage 42 can be suppressed, and the temperature rise of the exposure apparatus 3 can be suppressed. That is, the same effect as in Example 12 can be achieved. Note that the heat insulating member 55 may be assembled on the upper surface of the exhaust duct 2251 of Comparative Example 2 shown in FIGS. 9(a) to (d).

[0209] <Example 19> Next, Example 19 of the present invention will be described. Example 19 has a modified shape of the exhaust duct 1451 as compared with Example 15. For this reason, the same configurations as those in Example 15 will be described with illustration omitted or the same reference numerals in the drawings.

[0210] FIG. 40 shows a schematic cross-sectional view near the exhaust duct 2151 according to Example 19. FIG. 41(a) is a perspective view showing the exhaust duct 2151 and the heat insulating member 155 according to Example 19, FIG. 41(b) is a front view showing the exhaust duct 2151 and the heat insulating member 155, FIG. 41(c) is a plan view showing the exhaust duct 2151 and the heat insulating member 155, and FIG. 41(d) is a side view showing the exhaust duct 2151 and the heat insulating member 155.

[0211] As shown in FIGS. 40 to 41(d), the exhaust duct 2151 according to the present embodiment has the same shape as the exhaust duct of Comparative Example 1 shown in FIGS. 8(a) to (d). And a heat insulating member 155 similar to that in Example 15 is assembled to the second wall portion D of the exhaust duct 2151 close to the cleaning device 6. Thereby, heat transfer from the exhaust duct 2151 to the cleaning device 6 can be suppressed, and the temperature rise of the cleaning device 6 can be suppressed as in Example 15. Note that the heat insulating member 155 may be assembled to the second wall portion D of the exhaust duct 2251 of Comparative Example 2 shown in FIGS. 9(a) to (d).

[0212] <Example 20> Next, Example 20 of the present invention will be described. Example 20 has a modified shape of the exhaust heat duct 51 compared to Example 16. Therefore, for the same configurations as in Example 16, illustration will be omitted or the same reference numerals will be used in the drawings for explanation.

[0213] FIG. 42 shows a schematic cross-sectional view near the exhaust heat duct 2151 according to Example 20. FIG. 43(a) is a perspective view showing the exhaust heat duct 2151 and the heat insulating member 255 according to Example 20, FIG. 43(b) is a front view showing the exhaust heat duct 2151, FIG. 43(c) is a plan view showing the exhaust heat duct 2151 and the heat insulating member 255, and FIG. 43(d) is a side view showing the exhaust heat duct 2151 and the heat insulating member 255.

[0214] As shown in FIGS. 42 to 43(d), the exhaust heat duct 2151 according to the present embodiment has the same shape as the exhaust heat duct of Comparative Example 1 shown in FIGS. 8(a) to (d). And a heat insulating member 255 similar to that of Example 16 is assembled to the first wall portion C close to the fixing device 20 of the exhaust heat duct 2151.

[0215] By assembling the heat insulating member 255 to the first wall portion C of the exhaust heat duct 2151, the amount of exhaust heat from the fixing device 20 to the exhaust heat duct 2151 can be reduced. Thereby, similar to Example 16, the temperature rise of the cleaning device 6 and the exposure device 3 can be suppressed. Note that a heat insulating member 255 may be assembled to the first wall portion C of the exhaust heat duct 2251 of Comparative Example 2 shown in FIGS. 9(a) to (d).

[0216] <Other Embodiments> In Example 3, the exhaust heat fins 53 were attached to the main body 651e having substantially the same shape as that in Example 1 from the downstream side in the conveyance direction CD, but the present invention is not limited to this. For example, as shown in Modification 1 of FIG. 44(a), the exhaust heat fins 53 may be attached to the main body 2151e having the same shape as that in Comparative Example 1 shown in FIGS. 8(a) to 8(d) from the downstream side in the conveyance direction CD. The main body 2151e and the exhaust heat fins 53 constitute an exhaust heat duct 1851A as a duct. Even in this case, the same effects as those in Example 3 can be achieved. Further, the exhaust heat fins 53 may be attached to the exhaust heat duct 2251 of Comparative Example 2 shown in FIGS. 9(a) to 9(d) from the downstream side in the conveyance direction CD.

[0217] Also, as shown in Modification 2 of FIG. 44(b), the exhaust heat fins 53 may be attached to the main body 2151e having the same shape as that in Comparative Example 1 shown in FIGS. 8(a) to 8(d) from the upstream side in the conveyance direction CD. The main body 2151e and the exhaust heat fins 53 constitute an exhaust heat duct 1851B as a duct. Even in this case, the same effects as those in Example 3 can be achieved. Further, the exhaust heat fins 53 may be attached to the exhaust heat duct 2251 of Comparative Example 2 shown in FIGS. 9(a) to 9(d) from the upstream side in the conveyance direction CD.

[0218] In Example 6, the protruding portion 551b having the same function as the exhaust heat fins 53 was provided on the exhaust heat duct 551 having substantially the same shape as that in Example 1, but the present invention is not limited to this. For example, as shown in Modification 3 of FIG. 44(c), the protruding portion 551b may be provided on the first wall portion C close to the fixing device 20 of the exhaust heat duct 2151 having the same shape as that in Comparative Example 1 shown in FIGS. 8(a) to 8(d). Even in this case, the same effects as those in Example 6 can be achieved. Further, the protruding portion 551b may be provided on the first wall portion C of the exhaust heat duct 2251 of Comparative Example 2 shown in FIGS. 9(a) to 9(d).

[0219] Further, as in the modification example 4 shown in FIG. 44(d), a protruding portion 551b may be provided on a second wall portion D close to the cleaning device 6 of the exhaust heat duct 2151 having the same shape as that of the comparative example 1 shown in FIGS. 8(a) to (d). Even in this case, the same effects as those of the sixth embodiment can be achieved. Further, the protruding portion 551b may be provided on the second wall portion D of the exhaust heat duct 2251 of the comparative example 2 shown in FIGS. 9(a) to (d).

[0220] Also, in any of the above-described embodiments and modification examples, the fixing device 20 had the heating roller 30 having a built-in heat source, but the present invention is not limited thereto. For example, various heaters such as a ceramic heater and a halogen heater can be applied as the heat source of the heating roller 30. Further, instead of the heating roller 30, a fixing film formed in a film shape may be used. The fixing film is heated by various heaters such as a ceramic heater and a halogen heater. Further, instead of the heating roller 30, a fixing belt having a heat generating layer may be used, and the heat generating layer is heated by electromagnetic induction heating.

[0221] Also, all of the above-described embodiments, modification examples, and comparative examples may be arbitrarily combined.

[0222] Further, the disclosure of the present embodiment includes the following configuration examples and method examples. (Configuration 1) In an image forming apparatus that forms a toner image on a sheet, a rotatable image carrier, a developing member that forms a toner image on the image carrier by supplying toner to the image carrier, a transfer member that transfers the toner image formed on the image carrier to a sheet, a cleaning member that contacts the surface of the image carrier and removes toner from the surface of the image carrier, a toner collection container that collects the toner removed from the surface of the image carrier by the cleaning member, a fixing unit that fixes the toner image transferred to the sheet by the transfer member to the sheet, A duct is provided between the toner collection container and the fixing unit to form an air passage through which air flows toward the outside of the image forming apparatus. The duct has a first wall portion facing the fixing unit and a second wall portion facing the toner collection container. The first wall portion is inclined with respect to the second wall portion. An image forming apparatus characterized by the above. (Configuration 2) The first wall portion is inclined with respect to the second wall portion such that the distance between the first end portion of the first wall portion, which is closest to the conveyance path through which the sheet passes between the transfer member and the fixing unit, and the second wall portion is shorter than the distance between the second end portion of the first wall portion, which is farthest from the conveyance path, and the second wall portion. The image forming apparatus according to Configuration 1, characterized by the above. (Configuration 3) The first wall portion is formed linearly when viewed in the rotational axis direction of the image carrier. The image forming apparatus according to Configuration 1 or 2, characterized by the above. (Configuration 4) The first wall portion is formed to be curved when viewed in the rotational axis direction of the image carrier. The image forming apparatus according to Configuration 1 or 2, characterized by the above. (Configuration 5) The second wall portion extends in the vertical direction. The image forming apparatus according to any one of Configurations 1 to 4, characterized by the above. (Configuration 6) The fixing unit has a fixing member that heats the toner image on the sheet and a fixing cover that covers the fixing member. The fixing cover has a facing surface that faces the first wall portion and extends along the first wall portion. The image forming apparatus according to any one of Configurations 1 to 5, characterized by the above. (Configuration 7) In an image forming apparatus that forms a toner image on a sheet, A rotatable image carrier, A developing member that forms a toner image on the image carrier by supplying toner to the image carrier, A transfer member that transfers the toner image formed on the image carrier to a sheet, A cleaning member that contacts the surface of the image carrier and removes toner from the surface of the image carrier, A toner collection container that collects the toner removed from the surface of the image carrier by the cleaning member, A fixing unit that fixes the toner image transferred to the sheet by the transfer member to the sheet, A duct that forms an air passage through which air directed outside the image forming apparatus passes and is provided between the toner collection container and the fixing unit, The duct includes a duct having a first wall portion facing the fixing unit and a second wall portion facing the toner collection container, At least one of the first wall portion and the second wall portion has a plurality of protruding portions protruding toward the air passage, An image forming apparatus characterized by this. (Configuration 8) The duct has a first member that forms the air passage and a second member that has the plurality of protruding portions and is attached to the first member, The image forming apparatus according to Configuration 7, characterized by this. (Configuration 9) The duct is made of a metal material, The plurality of protruding portions are formed by drawing, The image forming apparatus according to Configuration 7, characterized by this. (Configuration 10) The plurality of protruding portions are provided on the first wall portion, The image forming apparatus according to Configuration 7, characterized by this. (Configuration 11) The plurality of protruding portions are provided on the second wall portion, The image forming apparatus according to Configuration 7, characterized by this. (Configuration 12) In an image forming apparatus that forms a toner image on a sheet, A rotatable image carrier, A developing member that forms a toner image on the image carrier by supplying toner to the image carrier, A transfer member that transfers the toner image formed on the image carrier to a sheet, A cleaning member that contacts the surface of the image carrier and removes toner from the surface of the image carrier, A toner collection container that collects the toner removed from the surface of the image carrier by the cleaning member, A fixing unit that fixes the toner image transferred to the sheet by the transfer member to the sheet, A duct that forms an air passage through which air directed to the outside of the image forming apparatus passes and is provided between the toner collection container and the fixing unit, The duct has a first wall portion facing the fixing unit and a second wall portion facing the toner collection container, At least one of the first wall portion and the second wall portion has a plurality of openings communicating with the air passage, An image forming apparatus characterized by the above. (Configuration 13) In an image forming apparatus that forms a toner image on a sheet, A rotatable image carrier, A developing member that forms a toner image on the image carrier by supplying toner to the image carrier, A transfer member that transfers the toner image formed on the image carrier to a sheet, A cleaning member that contacts the surface of the image carrier and removes toner from the surface of the image carrier, A toner collection container that collects the toner removed from the surface of the image carrier by the cleaning member, A fixing unit that fixes the toner image transferred to the sheet by the transfer member to the sheet, A duct that forms an air passage through which air directed to the outside of the image forming apparatus passes and is provided between the toner collection container and the fixing unit, The duct has a first wall portion facing the fixing unit, a second wall portion facing the toner collection container, and a partition wall disposed between the first wall portion and the second wall portion. The partition wall divides the air passage into a first air passage formed between the partition wall and the first wall portion and a second air passage formed between the partition wall and the second wall portion. An image forming apparatus characterized by the above. (Configuration 14) In an image forming apparatus that forms a toner image on a sheet, a rotatable image carrier, a developing member that forms a toner image on the image carrier by supplying toner to the image carrier, a transfer member that transfers the toner image formed on the image carrier to a sheet, a cleaning member that contacts the surface of the image carrier and removes toner from the surface of the image carrier, a toner collection container that collects the toner removed from the surface of the image carrier by the cleaning member, a fixing unit that fixes the toner image transferred to the sheet by the transfer member to the sheet, a duct that forms an air passage through which air flows toward the outside of the image forming apparatus and is provided between the toner collection container and the fixing unit, The fixing unit has a fixing member that heats the toner image on the sheet and a fixing cover that covers the fixing member. The duct has a first wall portion facing the fixing unit and a second wall portion facing the toner collection container. The first wall portion of the duct is disposed downstream in the sheet conveyance direction from the straight line so as not to intersect a straight line extending vertically through the upstream end in the sheet conveyance direction of the fixing cover when viewed in the rotational axis direction of the image carrier. An image forming apparatus characterized by the above. (Configuration 15) The duct is made of a metal material. The fixing cover is made of a resin material. The image forming apparatus according to Configuration 14, characterized by the following. (Configuration 16) In an image forming apparatus that forms a toner image on a sheet, a rotatable image carrier, a developing member that forms a toner image on the image carrier by supplying toner to the image carrier, a transfer member that transfers the toner image formed on the image carrier to a sheet, a cleaning member that contacts the surface of the image carrier and removes toner from the surface of the image carrier, a toner collection container that collects the toner removed from the surface of the image carrier by the cleaning member, a fixing unit that fixes the toner image transferred to the sheet by the transfer member, a duct that forms an air passage through which air flows toward the outside of the image forming apparatus and is provided between the toner collection container and the fixing unit, the duct having a first wall portion facing the fixing unit and a second wall portion facing the toner collection container, and a heat insulating member that is attached to at least one of the first wall portion and the second wall portion and has a lower thermal conductivity than the duct. An image forming apparatus characterized by the above. (Configuration 17) The heat insulating member is attached to the second wall portion. The image forming apparatus according to Configuration 16, characterized by the above. (Configuration 18) The heat insulating member is attached to the first wall portion. The image forming apparatus according to Configuration 16, characterized by the above. (Configuration 19) In an image forming apparatus that forms a toner image on a sheet, a rotatable image carrier, an exposure device that exposes the image carrier, a developing member that forms a toner image on the image carrier by supplying toner to the image carrier, a transfer member that transfers the toner image formed on the image carrier to a sheet, A cleaning member that abuts against the surface of the image carrier and removes toner from the surface of the image carrier; A toner collection container that collects the toner removed from the surface of the image carrier by the cleaning member; A fixing unit that fixes the toner image transferred to the sheet by the transfer member to the sheet; A support member that supports the exposure device; A duct that forms an air passage through which air flows toward the outside of the image forming apparatus, is provided between the toner collection container and the fixing unit, and is supported by the support member, the duct having a first wall portion facing the fixing unit and a second wall portion facing the toner collection container; A heat insulating member that is disposed between the support member and the duct and has a lower thermal conductivity than the duct; An image forming apparatus characterized by the above. (Configuration 20) In an image forming apparatus that forms a toner image on a sheet, A rotatable image carrier; An exposure device that exposes the image carrier; A developing member that forms a toner image on the image carrier by supplying toner to the image carrier; A transfer member that transfers the toner image formed on the image carrier to a sheet; A cleaning member that abuts against the surface of the image carrier and removes toner from the surface of the image carrier; A toner collection container that collects the toner removed from the surface of the image carrier by the cleaning member; A fixing unit that fixes the toner image transferred to the sheet by the transfer member to the sheet; A support member that supports the exposure device; A duct that forms an air passage through which air flows toward the outside of the image forming apparatus, is provided between the toner collection container and the fixing unit, and is supported by the support member, the duct having a first wall portion facing the fixing unit and a second wall portion facing the toner collection container; The duct has a lower thermal conductivity than the support member. An image forming apparatus characterized by this. (Configuration 21) The duct is made of a resin material. The support member is made of a metal material. The image forming apparatus according to Configuration 20, characterized by this. (Configuration 22) In an image forming apparatus that forms a toner image on a sheet, A rotatable image carrier, An exposure device that exposes the image carrier, A developing member that forms a toner image on the image carrier by supplying toner to the image carrier, A transfer member that transfers the toner image formed on the image carrier to a sheet, A cleaning member that contacts the surface of the image carrier and removes toner from the surface of the image carrier, A toner recovery container that recovers the toner removed from the surface of the image carrier by the cleaning member, A fixing unit that fixes the toner image transferred to the sheet by the transfer member to the sheet, A support member that supports the exposure device, A duct that forms an air passage through which air goes to the outside of the image forming apparatus, is provided between the toner recovery container and the fixing unit, and is supported by the support member. The duct has a first wall portion facing the fixing unit and a second wall portion facing the toner recovery container. A guide member that is arranged on the side opposite to the toner recovery container with respect to the conveyance path through which the sheet passes between the transfer member and the fixing unit and overlaps the fixing unit in the sheet conveyance direction, and guides the sheet toward the fixing nip portion of the fixing unit. The duct is arranged so as to overlap the guide member in the sheet conveyance direction. An image forming apparatus characterized by this. (Configuration 23) It is further provided with a fan that is arranged on one side of the duct in the direction of the rotation axis of the image carrier and sends air. When viewed in the direction of the rotation axis, the duct is arranged so as to overlap the fan. The image forming apparatus according to any one of Configurations 1 to 22, characterized in that. (Configuration 24) When viewed in the direction of the rotation axis of the image carrier, the second wall portion of the duct extends to a position closer to the conveyance path through which the sheet passes between the transfer member and the fixing unit than the cleaning member. The image forming apparatus according to any one of Configurations 1 to 23, characterized in that. (Configuration 25) The duct is arranged on the same side as the toner collection container with respect to the conveyance path through which the sheet passes between the transfer member and the fixing unit. The image forming apparatus according to any one of Configurations 1 to 24, characterized in that. (Configuration 26) The first wall portion is inclined with respect to the second wall portion. The image forming apparatus according to any one of Configurations 7 to 25, characterized in that. (Configuration 27) The distance between the first end portion of the first wall portion, which is closest to the conveyance path through which the sheet passes between the transfer member and the fixing unit, and the second wall portion is shorter than the distance between the second end portion of the first wall portion, which is farthest from the conveyance path, and the second wall portion. The first wall portion is inclined with respect to the second wall portion. The image forming apparatus according to any one of Configurations 7 to 26, characterized in that. (Configuration 28) The first wall portion is formed linearly when viewed in the direction of the rotation axis of the image carrier. The image forming apparatus according to any one of Configurations 7 to 27, characterized in that. (Configuration 29) The first wall portion is formed so as to be curved when viewed in the direction of the rotation axis of the image carrier. The image forming apparatus according to any one of Configurations 7 to 27, characterized in that. (Configuration 30) The second wall portion extends in the vertical direction. The image forming apparatus according to any one of Claims 7 to 29, characterized in that

Explanation of Signs

[0223] 1: Image carrier (photosensitive drum) / 3: Exposure device / 5: Transfer member (transfer roller) / 6a: Toner recovery container (container) / 20: Fixing unit (fixing device) / 25: Developing member (developing roller) / 29: Cleaning member (cleaning blade) / 30: Fixing member (heating roller) / 32: Guide member (pre-fixing guide) / 33: Fixing cover / 42: Support member (scanner stand) / 50: Fan (exhaust fan) / 51, 151, 251, 351, 451, 551, 651, 751, 851, 951, 1051, 1151, 1251, 1351, 1451, 1651, 1851A, 1851B: Duct (exhaust duct) / 53, 653: Second member (exhaust fins) / 53c, 551b, 751b: Protrusion / 55, 155, 255: Heat insulating member / 56: Opening (duct vent) / 251e, 651e: First member (main body portion) / 351f, 851f: Partition wall / 933d: Upstream end / A: Image forming apparatus / AP: Air passage / B: Opposing surface (flat portion) / C: First wall portion / C1: First end / C2: Second end / CD: Sheet conveyance direction (conveyance direction) / D: Second wall portion / LN1: Straight line / SP1: First air passage / SP2: Second air passage / W: Rotation axis direction

Claims

1. In an image forming apparatus for forming a toner image on a sheet, a rotatable image carrier; a developing member that forms a toner image on the image carrier by supplying toner to the image carrier; a transfer member that transfers the toner image formed on the image carrier to a sheet; a cleaning member that contacts the surface of the image carrier and removes toner from the surface of the image carrier; a toner collection container that collects the toner removed from the surface of the image carrier by the cleaning member; a fixing unit that fixes the toner image transferred to the sheet by the transfer member to the sheet; a duct that forms an air passage through which air toward the outside of the image forming apparatus passes and is provided between the toner collection container and the fixing unit, wherein the duct has a first wall portion facing the fixing unit and a second wall portion facing the toner collection container, and the first wall portion is inclined with respect to the second wall portion. An image forming apparatus characterized by the above.

2. The first wall portion is inclined with respect to the second wall portion such that the distance between a first end portion of the first wall portion, which is closest to a conveyance path through which the sheet passes between the transfer member and the fixing unit, and the second wall portion is shorter than the distance between a second end portion of the first wall portion, which is farthest from the conveyance path, and the second wall portion. The image forming apparatus according to claim 1, characterized by the above.

3. The first wall portion is formed linearly as viewed in the rotational axis direction of the image carrier. The image forming apparatus according to claim 1, characterized by the above.

4. The first wall portion is formed to be curved as viewed in the rotational axis direction of the image carrier. The image forming apparatus according to claim 1, characterized by the above.

5. The second wall portion extends in the vertical direction. The image forming apparatus according to claim 1, characterized by the above.

6. The fixing unit has a fixing member that heats the toner image on the sheet and a fixing cover that covers the fixing member, wherein the fixing cover has a facing surface that faces the first wall portion and extends along the first wall portion. The image forming apparatus according to claim 1, characterized by the above.

7. In an image forming apparatus for forming a toner image on a sheet, a rotatable image carrier; a developing member that forms a toner image on the image carrier by supplying toner to the image carrier; a transfer member that transfers the toner image formed on the image carrier to a sheet; A cleaning member that contacts the surface of the image carrier and removes toner from the surface of the image carrier; A toner collection container that collects the toner removed from the surface of the image carrier by the cleaning member; A fixing unit that fixes the toner image transferred to the sheet by the transfer member to the sheet; A duct that forms an air passage through which air directed to the outside of the image forming apparatus passes and is provided between the toner collection container and the fixing unit; The duct includes a duct having a first wall portion facing the fixing unit and a second wall portion facing the toner collection container; At least one of the first wall portion and the second wall portion has a plurality of protrusions protruding toward the air passage; An image forming apparatus characterized by the above.

8. The duct has a first member that forms the air passage and a second member that has the plurality of protrusions and is attached to the first member; The image forming apparatus according to claim 7, characterized in that.

9. The duct is made of a metal material, The plurality of protrusions are formed by drawing; The image forming apparatus according to claim 7, characterized in that.

10. The plurality of protrusions are provided on the first wall portion; The image forming apparatus according to claim 7, characterized in that.

11. The plurality of protrusions are provided on the second wall portion; The image forming apparatus according to claim 7, characterized in that.

12. In an image forming apparatus that forms a toner image on a sheet, A rotatable image carrier; A developing member that forms a toner image on the image carrier by supplying toner to the image carrier; A transfer member that transfers the toner image formed on the image carrier to a sheet; A cleaning member that contacts the surface of the image carrier and removes toner from the surface of the image carrier; A toner collection container that collects the toner removed from the surface of the image carrier by the cleaning member; A fixing unit that fixes the toner image transferred to the sheet by the transfer member to the sheet; A duct that forms an air passage through which air directed to the outside of the image forming apparatus passes and is provided between the toner collection container and the fixing unit; The duct has a first wall portion facing the fixing unit and a second wall portion facing the toner collection container; At least one of the first wall portion and the second wall portion has a plurality of openings communicating with the air passage. An image forming apparatus characterized by this.

13. In an image forming apparatus that forms a toner image on a sheet, A rotatable image carrier; A developing member that forms a toner image on the image carrier by supplying toner to the image carrier; A transfer member that transfers the toner image formed on the image carrier to a sheet; A cleaning member that contacts the surface of the image carrier and removes toner from the surface of the image carrier; A toner collection container that collects the toner removed from the surface of the image carrier by the cleaning member; A fixing unit that fixes the toner image transferred to the sheet by the transfer member to the sheet; A duct that forms an air passage through which air directed to the outside of the image forming apparatus passes and is provided between the toner collection container and the fixing unit, The duct has a first wall portion facing the fixing unit, a second wall portion facing the toner collection container, and a partition wall disposed between the first wall portion and the second wall portion. The partition wall divides the air passage into a first air passage formed between the first wall portion and a second air passage formed between the second wall portion. An image forming apparatus characterized by this.

14. In an image forming apparatus that forms a toner image on a sheet, A rotatable image carrier; A developing member that forms a toner image on the image carrier by supplying toner to the image carrier; A transfer member that transfers the toner image formed on the image carrier to a sheet; A cleaning member that contacts the surface of the image carrier and removes toner from the surface of the image carrier; A toner collection container that collects the toner removed from the surface of the image carrier by the cleaning member; A fixing unit that fixes the toner image transferred to the sheet by the transfer member to the sheet; A duct that forms an air passage through which air directed to the outside of the image forming apparatus passes and is provided between the toner collection container and the fixing unit, The fixing unit has a fixing member that heats the toner image on the sheet and a fixing cover that covers the fixing member. The duct has a first wall portion facing the fixing unit and a second wall portion facing the toner collection container. The first wall portion of the duct is arranged downstream in the sheet conveyance direction from the straight line so as not to intersect a straight line that extends vertically through the upstream end in the sheet conveyance direction of the fixing cover when viewed in the rotation axis direction of the image carrier. An image forming apparatus characterized by this.

15. The duct is made of a metal material. The fixing cover is made of a resin material. The image forming apparatus according to claim 14, characterized by this.

16. In an image forming apparatus that forms a toner image on a sheet, A rotatable image carrier; A developing member that forms a toner image on the image carrier by supplying toner to the image carrier; A transfer member that transfers the toner image formed on the image carrier to a sheet; A cleaning member that contacts the surface of the image carrier and removes toner from the surface of the image carrier; A toner collection container that collects the toner removed from the surface of the image carrier by the cleaning member; A fixing unit that fixes the toner image transferred to the sheet by the transfer member to the sheet; A duct that forms an air passage through which air goes to the outside of the image forming apparatus and is provided between the toner collection container and the fixing unit, the duct having a first wall portion facing the fixing unit and a second wall portion facing the toner collection container; An insulating member that is attached to at least one of the first wall portion and the second wall portion and has a lower thermal conductivity than the duct. An image forming apparatus characterized by this.

17. The insulating member is attached to the second wall portion. The image forming apparatus according to claim 16, characterized by this.

18. The insulating member is attached to the first wall portion. The image forming apparatus according to claim 16, characterized by this.

19. In an image forming apparatus that forms a toner image on a sheet, A rotatable image carrier; An exposure device that exposes the image carrier; A developing member that forms a toner image on the image carrier by supplying toner to the image carrier; A transfer member that transfers the toner image formed on the image carrier to a sheet; A cleaning member that contacts the surface of the image carrier and removes toner from the surface of the image carrier; A toner collection container that collects the toner removed from the surface of the image carrier by the cleaning member; A fixing unit that fixes the toner image transferred to the sheet by the transfer member; A support member that supports the exposure device; A duct that forms an air passage through which air directed to the outside of the image forming apparatus passes, is provided between the toner recovery container and the fixing unit, and is supported by the support member, the duct having a first wall portion facing the fixing unit and a second wall portion facing the toner recovery container; A heat insulating member disposed between the support member and the duct and having a lower thermal conductivity than the duct; An image forming apparatus characterized by the above.

20. In an image forming apparatus that forms a toner image on a sheet, A rotatable image carrier; An exposure device that exposes the image carrier; A developing member that forms a toner image on the image carrier by supplying toner to the image carrier; A transfer member that transfers the toner image formed on the image carrier to the sheet; A cleaning member that contacts the surface of the image carrier and removes toner from the surface of the image carrier; A toner recovery container that recovers the toner removed from the surface of the image carrier by the cleaning member; A fixing unit that fixes the toner image transferred to the sheet by the transfer member; A support member that supports the exposure device; A duct that forms an air passage through which air directed to the outside of the image forming apparatus passes, is provided between the toner recovery container and the fixing unit, and is supported by the support member, the duct having a first wall portion facing the fixing unit and a second wall portion facing the toner recovery container; The duct has a lower thermal conductivity than the support member; An image forming apparatus characterized by the above.

21. The duct is made of a resin material; The support member is made of a metal material; The image forming apparatus according to claim 20, characterized by the above.

22. In an image forming apparatus that forms a toner image on a sheet, A rotatable image carrier; An exposure device that exposes the image carrier; A developing member that forms a toner image on the image carrier by supplying toner to the image carrier; A transfer member that transfers the toner image formed on the image carrier to the sheet; A cleaning member that contacts the surface of the image carrier and removes toner from the surface of the image carrier; A toner recovery container that recovers the toner removed from the surface of the image carrier by the cleaning member; A fixing unit that fixes the toner image transferred to the sheet by the transfer member; A support member that supports the exposure device; A duct that forms an air passage through which air toward the outside of the image forming apparatus passes, is provided between the toner collection container and the fixing unit, and is supported by the support member, the duct having a first wall portion facing the fixing unit and a second wall portion facing the toner collection container; A guide member that is disposed on the side opposite to the toner collection container with respect to the conveyance path through which the sheet passes between the transfer member and the fixing unit and overlaps the fixing unit in the sheet conveyance direction, and guides the sheet toward the fixing nip portion of the fixing unit; The duct is disposed so as to overlap the guide member in the sheet conveyance direction. An image forming apparatus characterized by the above.

23. Further comprising a fan that is disposed on one side of the duct in the axial direction of rotation of the image carrier and sends air; When viewed in the axial direction of rotation, the duct is disposed so as to overlap the fan. The image forming apparatus according to any one of claims 1 to 22, characterized by the above.

24. When viewed in the axial direction of rotation of the image carrier, the second wall portion of the duct extends to a position closer to the conveyance path through which the sheet passes between the transfer member and the fixing unit than the cleaning member. The image forming apparatus according to any one of claims 1 to 22, characterized by the above.

25. The duct is disposed on the same side as the toner collection container with respect to the conveyance path through which the sheet passes between the transfer member and the fixing unit. The image forming apparatus according to any one of claims 1 to 22, characterized by the above.

26. The first wall portion is inclined with respect to the second wall portion. The image forming apparatus according to any one of claims 7 to 22, characterized by the above.

27. The first wall portion is inclined with respect to the second wall portion such that the distance between the first end portion of the first wall portion closest to the conveyance path through which the sheet passes between the transfer member and the fixing unit and the second wall portion is shorter than the distance between the second end portion of the first wall portion farthest from the conveyance path and the second wall portion. The image forming apparatus according to any one of claims 7 to 22, characterized by the above.

28. The first wall portion is formed linearly when viewed in the rotational axis direction of the image carrier. The image forming apparatus according to any one of claims 7 to 22, characterized in that.

29. The first wall portion is formed to be curved when viewed in the rotational axis direction of the image carrier. The image forming apparatus according to any one of claims 7 to 22, characterized in that.

30. The second wall portion extends in the vertical direction. The image forming apparatus according to any one of claims 7 to 22, characterized in that.

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