Image forming apparatus

Abstract

The present disclosure relates to an image forming apparatus including: an image bearing member; a developing member; a transfer member; a cleaning member configured to remove toner from a surface of the image bearing member; a toner collecting container configured to collect toner removed from a surface of the image bearing member by the cleaning member; a fixing unit configured to fix the toner image transferred onto a sheet by the transfer member to the sheet; and a duct disposed between the toner collecting container and the fixing unit, the duct forming an air passage through which air flowing to the outside of the image forming apparatus flows. The duct includes a first wall portion opposed to the fixing unit and a second wall portion opposed to the toner collecting container. The first wall portion is inclined with respect to the second wall portion.

Description

Technical Field

[0001] The present invention relates to an imaging device for forming an image on a sheet. Background Art

[0002] Heretofore, an imaging device based on an electrophotographic system and equipped with a process cartridge and a fixing device has been proposed (see Japanese Patent Application Laid-Open No. H04-70680). The process cartridge is formed by integrally assembling a photosensitive drum, a cleaner, a primary charging unit, and a developing unit. A cross-flow fan is disposed between the fixing device and the process cartridge. The cross-flow fan sucks air that has been warmed by the fixing device serving as a heat source and discharges the air toward the outside of the imaging device. The blades and the housing of the cross-flow fan also serve as a partition for blocking the transfer of radiant heat from the fixing device.

[0003] However, with regard to improvement of heat insulation performance, there is room for improvement in the blades and the housing of the cross-flow fan disclosed in Japanese Patent Application Laid-Open No. H04-70680. Summary of the Invention

[0004] According to one aspect of the present invention, an imaging device configured to form a toner image on a sheet includes: an image carrier member configured to rotate; a developing member configured to form a toner image on the image carrier member by supplying toner to the image carrier member; a transfer member configured to transfer the toner image formed on the image carrier member to the sheet; a cleaning member configured to abut against a surface of the image carrier member and remove toner from the surface of the image carrier member; a toner collection container configured to collect toner removed from the surface of the image carrier member by the cleaning member; a fixing unit configured to fix the toner image transferred to the sheet by the transfer member to the sheet; and a duct disposed between the toner collection container and the fixing unit. The duct forms an air passage through which air flowing toward the outside of the imaging device flows. The duct includes 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.

[0005] Other features of the present invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. Brief Description of the Drawings

[0006] Figure 1 is a schematic cross-sectional view of an imaging device according to Embodiment 1.

[0007] Figure 2 It is a front view of the imaging device.

[0008] Figure 3 It is a perspective view of the imaging device.

[0009] Figure 4 It is a left side view of the imaging device.

[0010] Figure 5 It is a perspective view of the vicinity of the main body frame.

[0011] Figure 6 It is a schematic cross-sectional view of the vicinity of the exhaust heat pipe.

[0012] Figure 7A It is a perspective view of the exhaust heat pipe according to Embodiment 1.

[0013] Figure 7B It is a front view of the exhaust heat pipe.

[0014] Figure 7C It is a plan view of the exhaust heat pipe.

[0015] Figure 7D It is a side view of the exhaust heat pipe.

[0016] Figure 8A It is a perspective view of the exhaust heat pipe according to Comparative Example 1.

[0017] Figure 8B It is a front view of the exhaust heat pipe.

[0018] Figure 8C It is a plan view of the exhaust heat pipe.

[0019] Figure 8D It is a side view of the exhaust heat pipe.

[0020] Figure 9A It is a perspective view of the exhaust heat pipe according to Comparative Example 2.

[0021] Figure 9B It is a front view of the exhaust heat pipe.

[0022] Figure 9C It is a plan view of the exhaust heat pipe.

[0023] Figure 9D It is a side view of the exhaust heat pipe.

[0024] Figure 10 It is a schematic cross-sectional view of the vicinity showing the exhaust heat pipe according to Embodiment 2.

[0025] Figure 11A It is a perspective view of the exhaust heat pipe according to Embodiment 2.

[0026] Figure 11BIt is a front view of the exhaust heat pipe.

[0027] Figure 11C It is a plan view of the exhaust heat pipe.

[0028] Figure 11D It is a side view of the exhaust heat pipe.

[0029] Figure 12 It is a schematic cross-sectional view showing the vicinity of the exhaust heat valve according to Embodiment 3.

[0030] Figure 13A It is a perspective view of the exhaust heat valve according to Embodiment 3.

[0031] Figure 13B It is a front view of the exhaust heat pipe.

[0032] Figure 13C It is a plan view of the exhaust heat pipe.

[0033] Figure 13D It is a side view of the exhaust heat pipe.

[0034] Figure 14A It is a perspective view showing the state in which the exhaust heat fins are assembled to the main body portion of the exhaust heat pipe according to Embodiment 3.

[0035] Figure 14B It is a side view showing the state in which the exhaust heat fins are assembled to the main body portion of the exhaust heat pipe.

[0036] Figure 15 It is a schematic cross-sectional view showing the vicinity of the exhaust heat pipe according to Embodiment 4.

[0037] Figure 16A It is a perspective view of the exhaust heat pipe according to Embodiment 4.

[0038] Figure 16B It is a front view of the exhaust heat pipe.

[0039] Figure 16C It is a plan view of the exhaust heat pipe.

[0040] Figure 16D It is a side view of the exhaust heat pipe.

[0041] Figure 17A It is a perspective view of the exhaust heat pipe according to Embodiment 5.

[0042] Figure 17B It is a front view of the exhaust heat pipe.

[0043] Figure 17C It is a plan view of the exhaust heat pipe.

[0044] Figure 17D It is a side view of the exhaust heat pipe.

[0045] Figure 18A Is a perspective view of the exhaust heat pipe according to Embodiment 6.

[0046] Figure 18B Is a front view of the exhaust heat pipe.

[0047] Figure 18C Is a plan view of the exhaust heat pipe.

[0048] Figure 18D Is a side view of the exhaust heat pipe.

[0049] Figure 19A Is a perspective view of the exhaust heat pipe according to Embodiment 7.

[0050] Figure 19B Is a front view of the exhaust heat pipe.

[0051] Figure 19C Is a plan view of the exhaust heat pipe.

[0052] Figure 19D Is a side view of the exhaust heat pipe.

[0053] Figure 20A Is a perspective view showing the state in which the exhaust heat fins according to Embodiment 7 are assembled to the main body portion.

[0054] Figure 20B Is a side view showing the state in which the exhaust heat fins are assembled to the main body portion.

[0055] Figure 21A Is a perspective view of the exhaust heat pipe according to Embodiment 8.

[0056] Figure 21B Is a front view of the exhaust heat pipe.

[0057] Figure 21C Is a plan view of the exhaust heat pipe.

[0058] Figure 21D Is a side view of the exhaust heat pipe.

[0059] Figure 22A Is a perspective view of the exhaust heat pipe according to Embodiment 9.

[0060] Figure 22B Is a front view of the exhaust heat pipe.

[0061] Figure 22C Is a plan view of the exhaust heat pipe.

[0062] Figure 22D Is a side view of the exhaust heat pipe.

[0063] Figure 23 Is a schematic cross-sectional view showing the vicinity of the exhaust heat pipe according to Embodiment 10.

[0064] Figure 24 It is a schematic cross-sectional view showing the vicinity of the exhaust heat pipe according to Embodiment 11.

[0065] Figure 25 It is a schematic cross-sectional view of the imaging device according to Embodiment 12.

[0066] Figure 26A It is a perspective view of the exhaust heat pipe according to Embodiment 12.

[0067] Figure 26B It is a front view of the exhaust heat pipe.

[0068] Figure 26C It is a plan view of the exhaust heat pipe.

[0069] Figure 26D It is a side view of the exhaust heat pipe.

[0070] Figure 27 It is a schematic cross-sectional view of the imaging device according to Embodiment 13.

[0071] Figure 28A It is a perspective view of the exhaust heat pipe according to Embodiment 13.

[0072] Figure 28B It is a front view of the exhaust heat pipe.

[0073] Figure 28C It is a plan view of the exhaust heat pipe.

[0074] Figure 28D It is a side view of the exhaust heat pipe.

[0075] Figure 29 It is a schematic cross-sectional view of the imaging device according to Embodiment 14.

[0076] Figure 30A It is a front view of the exhaust heat pipe according to Embodiment 14.

[0077] Figure 30B It is a plan view of the exhaust heat pipe.

[0078] Figure 30C It is a side view of the exhaust heat pipe.

[0079] Figure 31A It is a perspective view of the exhaust heat pipe according to Embodiment 14.

[0080] Figure 31B It is another perspective view of the exhaust heat pipe.

[0081] Figure 32 It is a schematic cross-sectional view showing the vicinity of the exhaust heat pipe according to Embodiment 15.

[0082] Figure 33A Is a perspective view of the exhaust heat pipe according to Embodiment 15.

[0083] Figure 33B Is a front view of the exhaust heat pipe.

[0084] Figure 33C Is a plan view of the exhaust heat pipe.

[0085] Figure 33D Is a side view of the exhaust heat pipe.

[0086] Figure 34 Is a schematic cross-sectional view showing the vicinity of the exhaust heat pipe according to Embodiment 16.

[0087] Figure 35A Is a perspective view of the exhaust heat pipe according to Embodiment 16.

[0088] Figure 35B Is a front view of the exhaust heat pipe.

[0089] Figure 35C Is a plan view of the exhaust heat pipe.

[0090] Figure 35D Is a side view of the exhaust heat pipe.

[0091] Figure 36 Is a schematic cross-sectional view showing the vicinity of the exhaust heat pipe according to Embodiment 17.

[0092] Figure 37A Is a perspective view of the exhaust heat pipe according to Embodiment 17.

[0093] Figure 37B Is a front view of the exhaust heat pipe.

[0094] Figure 37C Is a plan view of the exhaust heat pipe.

[0095] Figure 37D Is a side view of the exhaust heat pipe.

[0096] Figure 38 Is a schematic cross-sectional view showing the vicinity of the exhaust heat pipe according to Embodiment 18.

[0097] Figure 39A Is a perspective view of the exhaust heat pipe according to Embodiment 18.

[0098] Figure 39B Is a front view of the exhaust heat pipe.

[0099] Figure 39C Is a plan view of the exhaust heat pipe.

[0100] Figure 39D Is a side view of the exhaust heat pipe.

[0101] Figure 40 is a schematic cross-sectional view showing the vicinity of the exhaust heat pipe according to Embodiment 19.

[0102] Figure 41A is a perspective view of the exhaust heat pipe according to Embodiment 19.

[0103] Figure 41B is a front view of the exhaust heat pipe.

[0104] Figure 41C is a plan view of the exhaust heat pipe.

[0105] Figure 41D is a side view of the exhaust heat pipe.

[0106] Figure 42 is a schematic cross-sectional view showing the vicinity of the exhaust heat pipe according to Embodiment 20.

[0107] Figure 43A is a perspective view of the exhaust heat pipe according to Embodiment 20.

[0108] Figure 43B is a front view of the exhaust heat pipe.

[0109] Figure 43C is a plan view of the exhaust heat pipe.

[0110] Figure 43D is a side view of the exhaust heat pipe.

[0111] Figure 44A is a side view of the exhaust heat pipe according to Variant Example 1.

[0112] Figure 44B is a side view of the exhaust heat pipe according to Variant Example 2.

[0113] Figure 44C is a side view of the exhaust heat pipe according to Variant Example 3.

[0114] Figure 44D is a side view of the exhaust heat pipe according to Variant Example 4. Detailed Description of the Embodiments

[0115] Hereinafter, embodiments for implementing the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, shapes, and relative arrangements of the components taught in this specification can be arbitrarily changed according to the construction of the device to which this technology is applied or according to various conditions, and they are not intended to limit the scope of the present invention to the embodiments described below.

[0116] Embodiment 1

[0117] Overall Structure of the Imaging Device

[0118] First, an example of the overall configuration of the imaging device according to this embodiment will be described. The imaging device A according to this embodiment is a laser printer employing an electrophotographic system. An imaging device refers to a device 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, and includes a printer, a copier, a fax machine, and a multifunction copier. In addition to the main body having an imaging function, the imaging device may also have auxiliary devices (e.g., an optional feeder, an image reading device, and a sheet processing device) connected thereto. In this case, the entire system with the auxiliary devices connected is also regarded as a type of imaging device. Further, the imaging device includes an imaging unit that can form a monochromatic toner image or a full-color toner image on a recording material in the form of a sheet.

[0119] Figure 1 is a schematic cross-sectional view of the imaging device A according to Embodiment 1. As Figure 1 shown, the imaging device A includes a photosensitive drum 1, which is a drum-shaped or cylindrical electrophotographic photoreceptor and serves as an image carrier member. The photosensitive drum 1 is rotatably supported on the device main body M of the imaging device A and is driven to rotate by a drive source (not shown). Around the photosensitive drum 1, a charging roller 2, an exposure unit 3, a developing unit 4, a transfer roller 5, and a cleaning unit 6 are arranged in a specified order along the rotation direction of the photosensitive drum 1.

[0120] In addition, a recording material cassette 7 for storing a recording material P such as paper is arranged in the lower part in the drawing of the device main body M. Starting from the recording material cassette 7, a pickup roller 8, a feed roller 9, a retard roller 10, a pair of transfer rollers 11, a pair of registration rollers 12, a registration roller shutter 13, a top sensor 14, an upper pre-transfer guide 15, a lower pre-transfer guide 16, the transfer roller 5, an electrostatic elimination needle 17, a transfer guide 18, an attracting metal plate 19, a pre-fixing guide 32, a fixing device 20, a sheet discharge sensor 21, a pair of sheet discharge rollers 22, and a sheet discharge tray 23 are arranged in a specified order along the transfer path of the recording material P. The photosensitive drum 1, the charging roller 2, the exposure unit 3, the developing unit 4, the transfer roller 5, the cleaning unit 6, and the exposure unit 3 to be described later constitute an imaging unit 150 for forming an image (i.e., a toner image) on the recording material P.

[0121] Next, the imaging operation will be described. The photosensitive drum 1 is driven by a drive source (not shown) along Figure 1It rotates in the clockwise direction at a processing speed (i.e., circumferential speed) of 280 mm / s. In this embodiment, the outer diameter of the photosensitive drum 1 is 24 mm. The surface of the rotating photosensitive drum 1 is charged approximately uniformly to a predetermined potential having a predetermined polarity (in this embodiment, the predetermined polarity is negative polarity) by the charging roller 2. In this state, a charging bias (i.e., charging voltage) is applied to the charging roller 2 from a charging power source (i.e., high-voltage power source) not shown. Image exposure light is irradiated onto the surface of the charged photosensitive drum 1 through the exposure unit 3 based on image information input from a host computer not shown, and an electrostatic latent image (i.e., electrostatic image) is formed by eliminating negative charges from the exposed portion.

[0122] The electrostatic latent image formed on the photosensitive drum 1 is developed into a toner image by the developing unit 4. The developing unit 4 employs a contact developing system as the developing system. A stirring rod 28 is disposed inside the developing container of the developing unit 4. The stirring rod 28 rotates in the clockwise direction in the drawing to temporarily gather the toner not shown in the vicinity of the contact portion between the developing roller 25 and the toner supply roller 26. The temporarily gathered toner is supplied by the toner supply roller 26 rotating counterclockwise in the drawing to be carried on the developing roller 25.

[0123] By rotating the developing roller 25 counterclockwise, the toner supplied to the developing roller 25 passes through the developing blade 27 (i.e., control member) to be coated to an appropriate layer thickness. In this state, the toner supplied to the developing roller 25 slides against the surface of the developing blade 27 and is charged to negative polarity.

[0124] The toner coated on the developing roller 25 is transferred to the developing nip portion where the photosensitive drum 1 and the developing roller 25 face each other. In the developing nip portion, a part of the toner coated on the developing roller 25 is transferred to the photosensitive drum 1 by an electric field formed by the electrostatic latent image potential formed on the photosensitive drum 1 by the exposure unit 3 and the developing bias (i.e., developing voltage) applied to the developing roller 25 from a developing power source not shown. Therefore, the electrostatic latent image is developed into a toner image (i.e., visible image) by attaching the toner charged to the same polarity as the charge polarity of the photosensitive drum 1 to the exposed portion on the photosensitive drum 1 (i.e., reverse developing system). That is, the developing roller 25 serving as the developing member forms a toner image on the photosensitive drum 1 by supplying toner to the photosensitive drum 1.

[0125] The toner remaining on the developing roller 25 and not used for image development at the developing nip portion is removed by the rotation of the 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 gathered in the vicinity of the contact portion between the developing roller 25 and the toner supply roller 26 is re-supplied to the developing roller 25.

[0126] The toner image formed on the photosensitive drum 1 is transferred onto a recording material P such as paper by the action of a transfer roller 5 serving as a transfer member. The transfer roller 5 is pressed (i.e., pushed) toward the photosensitive drum 1 by a transfer pressure spring serving as a pressing member (not shown), so as to be in pressure contact with the photosensitive drum 1. Thereby, a transfer nip portion is formed, which is the contact portion between the photosensitive drum 1 and the transfer roller 5. This transfer nip portion holds and conveys the recording material P.

[0127] The transfer roller 5 is rotated by the rotation drive of the photosensitive drum 1. In this embodiment, the outer diameter of the transfer roller 5 is 14.0 mm. The transfer roller 5 holds and conveys the recording material P together with the photosensitive drum 1. In this state, a transfer bias (i.e., a transfer voltage, which is a DC voltage having a polarity opposite to the charge polarity of the toner during image development (i.e., the normal charge polarity)) is applied to the transfer roller 5 from a transfer power source (i.e., a 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. After the transfer, the transfer residual toner of the formed image remains on the photosensitive drum 1, which is collected by the cleaning unit 6.

[0128] A cleaning blade 29 serving as a cleaning member is disposed on the cleaning unit 6, and the cleaning blade 29 includes a support metal plate and an elastic rubber portion fixed to the end of the support metal plate. The end of the rubber portion disposed on the free end side of the cleaning blade 29 abuts against the photosensitive drum 1 in the opposite direction, whereby the cleaning blade 29 removes the transfer residual toner remaining on the photosensitive drum 1. In addition, a space (i.e., a waste toner container) for storing the collected waste toner is disposed on the cleaning unit 6.

[0129] The recording material P is supported on a recording material cassette 7, and the recording material P is fed by a pickup roller 8. The recording material P fed by the pickup roller 8 is sent out one by one at a separation nip portion formed by a feed roller 9 and a retard roller 10.

[0130] In addition, the recording material P is conveyed by a pair of conveying rollers 11 and a pair of aligning rollers 12 at a predetermined timing, and is guided by a pre-transfer upper guide 15 and a pre-transfer lower guide 16 to reach the transfer nip portion. By transferring the toner image onto the recording material P at the transfer nip portion, an image is formed on the recording material P.

[0131] Next, the operation of the imaging device A after an image has been formed on the recording material P will be described. The amount of charge formed by applying a transfer voltage to the surface of the recording material P on which a toner image has been transferred at the transfer nip portion is reduced by the static elimination needle 17. Thereafter, the recording material P is guided by the conveyance guide 18 and the pre-fixing guide 32 to be conveyed to the fixing device 20. The attracting metal plate 19 disposed on the conveyance guide 18 applies a force to attract the charged recording material P, whereby the recording material P can be conveyed more stably.

[0132] The fixing device 20 serving as a fixing unit includes a heating roller 30 and a pressure roller 31. The heating roller 30 serving as a fixing member is rotatably supported on the frame of the fixing device 20 and is driven to rotate by a drive source (not shown). The pressure roller 31 is in pressure contact with the heating roller 30 via a fixing pressure spring serving as a pressing member (not shown). Thereby, the heating roller 30 and the pressure roller 31 are in 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 heated while being nipped and conveyed at the fixing nip portion.

[0133] The unfixed toner image formed on the recording material P is melted by being fixed and pressed at the fixing device 20, and is thereby fixed onto the surface of the recording material P as a fixed image. The recording material P on which the toner image is fixed at the fixing device 20 is discharged by the sheet discharge roller pair 22 onto the sheet discharge tray 23 disposed on the upper surface of the apparatus main body M. In addition, the imaging device A can confirm the occurrence of a paper jam (i.e., a sheet jam) by sensing the leading end and the trailing end of the recording material P via the top sensor 14 and the sheet discharge sensor 21.

[0134] In addition, the imaging device A is equipped with a heat exhaust fan 50 and a heat exhaust duct 51, which will be described later, and an air passage formed by the heat exhaust duct 51 is disposed between the cleaning unit 6 and the fixing device 20. Therefore, the heat generated at the fixing device 20 and the imaging unit 150 can be effectively discharged. The air flow will be described in detail below.

[0135] Air flow

[0136] The air flow in the imaging device A according to the present embodiment will be described. Figure 2 is a front view of the imaging device A according to Embodiment 1, and Figure 3 is a perspective view of the imaging device A according to Embodiment 1. In Figure 2 and Figure 3 for the sake of illustration, the components near the sheet discharge roller pair 22 and the sheet discharge tray 23 are not shown.

[0137] As Figure 2 andFigure 3 As shown, the main body frame 43 is composed of a right side plate 40, a left side plate 41, and a scanner support 42, and the right side plate 40 and the left side plate 41 are connected by the scanner support 42. The main body frame 43 is a structure that constitutes the frame of the imaging device A, and in the width direction W orthogonal to the conveyance direction CD of the recording material P, the width of the main body frame 43 is substantially the same as the entire width of the imaging device A.

[0138] The scanner support 42 serving as a support member supports the exposure unit 3 that irradiates the photosensitive drum 1 with laser light. The fixing device 20 is attached to the main body frame 43 of the imaging device A and is fixed thereto by fixing screws (not shown). Therefore, during maintenance, the fixing device 20 can be detached from the main body frame 43 of the imaging device A by removing the fixing screws (not shown).

[0139] The exhaust heat fan 50 has an external dimension of 60 mm × 60 mm and is fixed to the right side plate 40 at a corresponding position between the cleaning unit 6 and the fixing device 20. That is, the exhaust heat fan 50 is disposed on one side in the width direction W of the exhaust heat duct 51. In addition, the exhaust heat fan 50 has a function of discharging the air inside the imaging device A to the outside of the device. In the following description, regarding the main body frame 43, the right side plate 40 side is referred to as the drive side, and the surface of the right side plate 40 to which the exhaust heat fan 50 is attached is referred to as the drive side surface. This is the right side surface when viewed from the front side of the imaging device A (i.e., the upstream side in the conveyance direction CD of the recording material P during imaging). In addition, conversely, the left side (i.e., the left side plate 41 side) when viewed from the front side of the imaging device A is referred to as the electronic component side, and the left side surface of the left side plate 41 is referred to as the electronic component side surface.

[0140] At the central portion in the width direction W of the imaging device A, at a corresponding position between the cleaning unit 6 and the fixing device 20, an exhaust heat duct 51 serving as a duct is disposed. The exhaust heat duct 51 is attached to the scanner support 42. The exhaust heat duct 51 forms an air passage for discharging the air on the electronic component side to the outside of the device by enabling the air to pass from the electronic component side to the drive side. The detailed function of the exhaust heat duct 51 will be described below.

[0141] Next, the heat sources of the imaging device A and the corresponding airflows will be described. The developing unit 4, the cleaning unit 6, and the exposure unit 3 of the imaging unit 150 generate heat during the imaging operation. In addition, the fixing device 20 includes a heating element, and heat is generated by heating the heating element. The heat generated by the heating element can be discharged to the outside of the device by the exhaust heat fan 50 discharging air.

[0142] Figure 4 is a left side view of the imaging device A according to Embodiment 1. As Figure 4As shown, 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 arranged in the lower part of the electronic component side surface of the left side plate 41, and the low-voltage power supply 45 converts the AC voltage supplied from the inlet as needed and supplies the necessary power for imaging operations (including driving and heating). The control board 46 is arranged in the front direction at the upper part of the electronic component side surface of the left side plate 41. The control board 46 is composed of a control unit (not shown) and a high-voltage unit (not shown). The control unit executes the control of the image signal generation board 47 and the entire imaging device A. The high-voltage unit is a voltage generation unit required for forming an image, which is composed of the above-mentioned charging power supply, developing power supply, and transfer power supply. The image signal generation board 47 is a generation unit of a VDO signal, which has been modulated into an electrical digital pixel signal according to the timing of print data (i.e., image information) input from a host computer (not shown). The exposure unit 3 controls the on / off of light based on the VDO signal. Heat generation due to loss occurs during the imaging operation by using the low-voltage power supply 45, the control board 46, and the image signal generation board 47.

[0143] Figure 5 is a perspective view of the vicinity of the main body frame 43 according to Embodiment 1, which shows that Figure 3 the fixing device 20, the low-voltage power supply 45, the control board 46, and the components of the image signal generation board 47 have been removed from Figure 5 shows the main body frame 43, the conveyance guide 18, the suction metal plate 19, the exposure unit 3, and the exhaust heat pipe 51.

[0144] As Figure 5 shown, ventilation holes 52 are arranged on the left side plate 41, where the ventilation holes 52 are located at positions corresponding to the electronic component side of the exhaust heat pipe 51. The heat generated from the electronic component side (e.g., the low-voltage power supply 45) can be discharged through the ventilation holes 52 and the exhaust heat pipe 51 by the exhaust of the exhaust heat fan 50. According to the above air flow, the heat generated in each area during the imaging operation can be better discharged without remaining in the imaging device A.

[0145] Exhaust heat pipe

[0146] The exhaust heat pipe 51 according to this embodiment forms an air passage AP communicating from the electronic component side to the driving side, and effectively suppresses the exhaust heat of the fixing device 20 from being conducted to the cleaning unit 6.

[0147] Figure 6 is a schematic cross-sectional view of the vicinity of the exhaust heat pipe 51 according to Embodiment 1. As Figure 6As shown, the exhaust heat pipe 51 is arranged near the fixing cover 33 of the fixing device 20 and near the cleaning unit 6. First, the fixing cover 33 will be described. The fixing cover 33 is arranged near the heating roller 30 and covers the heating roller 30. The fixing cover 33 prevents the user from contacting the heated heating roller 30 and also suppresses the occurrence of damage to the heating roller 30 caused by the user contacting the heating roller 30. The fixing cover 33 is made of a resin material (e.g., polycarbonate) having excellent heat resistance and electrical insulation properties, for example.

[0148] In the present embodiment, the center of the exhaust heat fan 50 is arranged 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. When viewed in the width direction W, the exhaust heat pipe 51 is arranged so as to overlap with the exhaust heat fan 50 serving as a fan. In addition, with respect to the conveyance path P10 described later, the exhaust heat pipe 51 is arranged on the same side as the container 6a of the cleaning unit 6.

[0149] It is characterized in that the shape of the front side of the fixing cover 33 extends from the upper side toward the lower side. Specifically, a flat portion B is formed on the front side of the fixing cover 33, and the flat portion B forms an angle of 71° with respect to the horizontal plane. This is to effectively conduct the heat of the fixing device 20 to the exhaust heat pipe 51 while preventing the heat from being conducted to the cleaning unit 6. The details of the effect will be described below.

[0150] The 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 clamping portion and the fixing clamping portion. In addition, in the exhaust heat pipe 51, the first wall portion C adjacent to the flat portion B of the fixing cover 33 includes 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.

[0151] The distance between the planar portion B of the fixing cover 33 and a part of the first wall portion C of the exhaust heat pipe 51 adjacent to the planar portion B of the fixing cover 33 is set to 3.0 mm or less. More specifically, the distance between the planar portion B and the first end portion C1 (which is the closest portion) of the first wall portion C is 1.5 mm, and the distance between the planar portion B and the second end portion C2 (which is the farthest portion) of the first wall portion C is 2.5 mm. Further, by arranging the exhaust heat pipe 51 made of a metal plate (i.e., a metal material) between the fixing device 20 and the cleaning unit 6, heat from the fixing device 20 is inhibited from being directly conducted to the cleaning unit 6. The cleaning unit 6 includes a container 6a for accommodating transfer residual toner, and the container 6a includes a surface 6b facing and adjacent to the exhaust heat pipe 51. The container 6a serving as a 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 pipe 51 adjacent to the surface 6b of the container 6a of the cleaning unit 6 and the surface 6b is 2.0 mm. When viewed in the width direction W, the second wall portion D extends to a position closer to the conveyance path P10 than the cleaning blade 29.

[0152] As described above, the pre-fixing guide 32 is arranged on the side opposite to the cleaning unit 6 with respect to the conveyance path P10. The pre-fixing guide 32 serving as a guiding member is arranged to overlap with the fixing device 20 in the conveyance direction CD and guide the recording material P toward the fixing nip portion of the fixing device 20. The exhaust heat pipe 51 is arranged to overlap with the pre-fixing guide 32 in the conveyance direction CD.

[0153] Figure 7A is a perspective view of the exhaust heat pipe 51 according to Embodiment 1, and Figure 7B is a front view of the exhaust heat pipe 51. Figure 7C is a plan view of the exhaust heat pipe 51, and Figure 7D is a side view of the exhaust heat pipe 51.

[0154] As Figures 7A to 7D shown, the exhaust heat pipe 51 extends such that the width direction W is the longitudinal direction. The exhaust heat pipe 51 includes a first wall portion C facing the planar portion B of the fixing cover 33, a second wall portion D facing the cleaning unit 6, and an upper surface 51a connecting the first wall portion C and the second wall portion D. In other words, the exhaust heat pipe 51 includes 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 mounting portions 54a and 54b and a positioning portion 54c.

[0155] The exhaust heat pipe 51 is attached to the scanner bracket 42 of the main body frame 43 by sliding in the thrust direction (i.e., the width direction W). By attaching the exhaust heat pipe 51 to the scanner bracket 42 by sliding, the positioning portion 54c abuts against the abutting portion of the scanner bracket 42, and the exhaust heat pipe 51 is thereby positioned on the scanner bracket 42. In this state, the mounting portions 54a and 54b are joined to the scanner bracket 42 by fixing screws, so that the exhaust heat pipe 51 is fixed to the scanner bracket 42.

[0156] The second wall portion D disposed adjacent to the cleaning unit 6 on the front side of the exhaust heat pipe 51 has a cross-sectional length of 32 mm orthogonal to the width direction W. According to the present embodiment, the upper surface 51a extends in the horizontal direction, and the angle θ1 formed by the second wall portion D of the exhaust heat pipe 51 and the upper surface 51a is 90°. That is, the second wall portion D extends in the vertical direction. The length of the first wall portion C located on the rear side of the exhaust heat pipe 51 and adjacent to the fixing cover 33 in a cross section orthogonal to the width direction W is 30 mm. The angle θ2 formed by the first wall portion C of the exhaust heat pipe 51 and the upper surface 51a is 75°. That is, when viewed along the width direction W parallel to the rotation axis direction of the photosensitive drum 1, the first wall portion C linearly extends along a direction orthogonal to the vertical direction. The width direction W may also be referred to as the rotation axis direction of the photosensitive drum 1.

[0157] 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.

[0158] Effects of Embodiment 1

[0159] The effects of the present embodiment will be described. According to the present embodiment, the flat portion B of the fixing cover 33 is inclined from the vertical direction (i.e., the vertical direction or the gravity direction), and the first wall portion C of the exhaust heat pipe 51 is arranged adjacent to the flat portion B. Thereby, a large amount of air can flow through the exhaust heat pipe 51 to discharge a larger amount of heat of the fixing device 20 while reducing the heat conducted to the cleaning unit 6.

[0160] The planar portion B, which serves as the opposing 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 planar portion B of the fixing cover 33 adjacent to the exhaust heat pipe 51, the heat of the fixing cover 33 heated by the heating roller 30 can be effectively conducted to the exhaust heat pipe 51. According to the present embodiment, the first wall portion C of the exhaust heat pipe 51 is inclined along the planar portion B from the vertical direction (i.e., the vertical direction or the direction of gravity). Thereby, the portion of the air passage AP formed by the exhaust heat pipe 51 that overlaps with the fins 50a of the exhaust heat fan 50 (i.e., the space into which heat can be discharged by the exhaust heat fan 50) can be widened, and the heat of the exhaust heat pipe 51 can be further reduced.

[0161] In the field of imaging devices, in order to improve productivity, the heat generated by the fixing device has been increased, and further, in order to reduce the size of the device, there is a tendency to arrange the cleaning device and the fixing device adjacent to each other. However, when the temperature of the cleaning device rises due to the heat of the fixing device, the transfer residual toner stored inside the cleaning device may aggregate. If the transfer residual toner aggregates in the cleaning device, the transfer residual toner that has been removed from the photosensitive drum by the cleaning blade may leak from the cleaning device.

[0162] By constructing the fixing cover 33 and the exhaust heat pipe 51 as in the present embodiment, the temperature rise of the cleaning unit 6 can be suppressed, and the aggregation of the transfer residual toner and its leakage from the cleaning unit 6 can be suppressed.

[0163] The secondary effect will be described. The thermistor 34 that detects the temperature of the heating roller 30 includes a base portion 34a attached to the fixing cover 33, an arm portion 34b extending downward from the base portion 34a, and a temperature detection portion 34c disposed inside the base portion 34a. The arm portion 34b is arranged to be elastically deformable so that it can stably abut against the heating roller 30. The arm portion 34b is connected in such a way that heat can be transferred to the temperature detection portion 34c. In the present embodiment, the temperature detection portion 34c is disposed on the base portion 34a, but the present technology is not limited thereto, and the temperature detection portion 34c may be disposed on an outer portion of the base portion 34a.

[0164] As described above, the thermistor 34 can detect the temperature of the heating roller 30, but there is a problem that the detected temperature may deviate slightly due to the temperature around the heating roller 30, particularly the temperature of the fixing cover 33. This is because the state of heat transfer to the temperature detection portion 34c may change due to the influence of changes in the ambient temperature of the base portion 34a and the arm portion 34b of the thermistor 34 or their peripheries.

[0165] Even when the temperature of the heating roller 30 is exactly the same, if the temperature of the fixing cover 33 or the ambient temperature around the base 34a, arm portion 34b, and temperature detection portion 34c of the thermistor 34 increases, the heat inflow to the temperature detection portion 34c through the heat transfer path decreases, and the detected temperature of the thermistor 34 slightly increases. This means that the detected temperature of the thermistor 34 for optimally fixing the toner image to the recording material P varies between the state where the fixing cover 33 is cooled and the state where the fixing cover is heated. This may result in a reduction in the margin for defects that occur when the temperature of the heating roller 30 is high or defects that occur when its temperature is low. For example, if the temperature of the heating roller 30 is high, defects such as the recording material P being wound around the heating roller 30 and causing a paper jam may occur, while if the temperature of the heating roller 30 is low, defects such as the toner image not being sufficiently fixed to the recording material P may occur.

[0166] According to the present embodiment, by tilting the flat portion B of the fixing cover 33 from the vertical orientation and arranging the first wall portion C of the exhaust heat pipe 51 adjacent to the flat portion B, the amount of temperature change of the fixing cover 33 caused by the usage state of the imaging device A can be reduced. Therefore, the occurrence of winding of the recording material P around the heating roller 30 due to the usage state of the imaging device A or fixing failures (e.g., blister images and cold offset) caused by insufficient fixing temperature can be suppressed.

[0167] Confirmation of the effects of Embodiment 1

[0168] Next, the results of an image output experiment for confirming the effects of the present embodiment will be described. Image output experiments were conducted on the present embodiment and Comparative Examples 1 and 2. Figure 8A is a perspective view of the exhaust heat pipe 2151 according to Comparative Example 1, and Figure 8B is a front view of the exhaust heat pipe 2151.

[0169] Figure 8C is a plan view of the exhaust heat pipe 2151, and Figure 8D is a side view of the exhaust heat pipe 2151. As Figures 8A to 8D shown, the angle formed by the upper surface 2151a of the exhaust heat pipe 2151 and the first wall portion C is 90°, and the length of the first wall portion C in a cross-section orthogonal to the width direction W is 30 mm. The angle formed by the upper surface 2151a and the second wall portion D is 90°, and the length of the second wall portion D in a cross-section orthogonal to the width direction W is 32 mm. The distance between the flat portion B of the fixing cover 33 and the first wall portion C at the closest part is 1.5 mm, and the distance between them at the farthest part is 4.0 mm.

[0170] Figure 9Ais a perspective view of the exhaust heat pipe 2251 of Comparative Example 2, and Figure 9B is a front view of the exhaust heat pipe 2251. Figure 9C is a plan view of the exhaust heat pipe 2251, and Figure 9D is a side view of the exhaust heat pipe 2251. As Figures 9A to 9D shown, the angle formed by the upper surface 2251a of the exhaust heat pipe 2251 and the first wall portion C is 75°, and the length of the first wall portion C in a cross section orthogonal to the width direction W is 30 mm. The angle formed by the upper surface 2251a and the second wall portion D is 75°, and the length of the second wall portion D in a cross section orthogonal to the width direction W is 32 mm. The distance between the flat portion B of the fixing cover 33 and the first wall portion C at the closest part is 1.5 mm, and the distance between them at the farthest part is 2.5 mm.

[0171] Table 1 shows the summary results of the configurations of the above-described present embodiment and Comparative Examples 1 and 2.

[0172] Table 1

[0173]

[0174] Except for the above differences, the configurations and operations of the imaging apparatuses according to Comparative Examples 1 and 2 are substantially the same as those of the imaging apparatus A according to the present embodiment.

[0175] First, an image output experiment regarding "toner leakage" will be described. An evaluation experiment of toner leakage will be described. Canon Red Label (product name, Canon E.U.) with a basis weight of 80 g / m 2 and a sheet size of A4 is used as the recording material P.

[0176] In the imaging apparatus used for the experiment, the processing speed during the experiment is 280 mm / sec, and its workload is 50 images per minute. The set temperature of the fixing device 20 is 200°C. Regarding the atmospheric environment for the experiment, the temperature is 32.5°C, and the humidity is 80%.

[0177] After leaving the imaging apparatus in a powered-off state overnight and confirming that the temperature inside the apparatus is sufficiently close to the atmospheric environment, a horizontal line image with an image coverage of 2% is printed on 10,000 sheets (i.e., 20,000 images) by double-sided continuous printing, and then it is confirmed whether toner leakage from the cleaning unit 6 has occurred inside the imaging apparatus.

[0178] Furthermore, in order to quantify the effect of the experimental results, thermocouples are brought into contact with the flat portion B, the first wall portion C, and the second wall portion D of the fixing cover 33 to measure the maximum temperature reached in each portion during printing.

[0179] Table 2 shows the results of the temperature and "toner leakage" image output experiments measured according to the evaluation experiments conducted using the imaging devices of this embodiment and Comparative Examples 1 and 2.

[0180] Table 2

[0181]

[0182] In the evaluation experiment of toner leakage according to this embodiment, no toner leakage occurred. Meanwhile, toner leakage has occurred according to Comparative Example 1. Toner leakage has also occurred according to Comparative Example 2.

[0183] Next, the achieved effects will be described based on the results of the temperature measured through the evaluation experiment of toner leakage. According to this embodiment, the first wall portion C of the exhaust heat pipe 51 is arranged adjacent to the flat portion B of the fixing cover 33, so that a large amount of heat can be discharged from the fixing device 20 while increasing the amount of air flowing through the exhaust heat pipe 51, thereby reducing the heat conducted to the cleaning unit 6.

[0184] Meanwhile, according to the comparative example, compared with this embodiment, the flat portion B of the fixing cover 33 and the first wall portion C of the exhaust heat pipe 2151 are not arranged adjacent to each other. In addition, according to Comparative Example 1, compared with this embodiment, the space (i.e., the air passage) inside the exhaust heat pipe 2151 is narrower. When comparing this embodiment and Comparative Example 1, the difference in the temperature reached by the fixing cover 33 and the temperature reached by the first wall portion C is 14.5 °C (= 65 °C - 50.5 °C) according to this embodiment, which is lower than 17 °C (= 71 °C - 54 °C) according to Comparative Example 1. Since in this embodiment, the flat portion B of the fixing cover 33 and the first wall portion C of the exhaust heat pipe 51 are arranged adjacent to each other, the heat of the fixing device 20 can be more easily absorbed by the exhaust heat pipe 51.

[0185] In this embodiment, the difference between the temperature of the first wall portion C and the temperature of the second wall portion D is 5 °C (= 50.5 °C - 45.5 °C), while in Comparative Example 1, the difference is 3 °C (= 54 °C - 51 °C). Therefore, this embodiment achieves an increased temperature difference of 2 °C because in this embodiment, the amount of air flowing through the exhaust heat pipe 51 increases, and a larger amount of heat can be discharged through the exhaust heat pipe 51.

[0186] Meanwhile, in Comparative Example 2, similar to this embodiment, the flat portion B of the fixing cover 33 and the first wall portion C of the exhaust heat pipe 2251 are arranged adjacent to each other. According to this embodiment, the difference between the temperature reached by the fixing cover 33 and the temperature reached by the first wall portion C is 14.5 °C (= 65 °C - 50.5 °C), which is approximately equal to 15 °C (71.5 °C - 65 °C) in Comparative Example 2.

[0187] However, in Comparative Example 2, the flow rate through the exhaust heat pipe 2251 is smaller than that in the present Example 1. Therefore, according to the present embodiment, the temperature of the second wall portion D is 45.5 °C, while according to Comparative Example 2, the temperature is as high as 53 °C. According to Comparative Example 2, the fixing cover 33 and the exhaust heat pipe 2251 are arranged adjacent to each other, such that the exhaust heat pipe 2251 absorbs the heat of the fixing device 20, but the amount of the air flow is not high, and the heat is conducted to the vicinity of the cleaning unit 6.

[0188] In the image output experiment presenting such an exhaust heat state, according to the present embodiment, the temperature reached by the second wall portion D is low, while according to Comparative Examples 1 and 2, the temperature reached by the second wall portion D is high, such that the transferred residual toner in the cleaning unit 6 accumulates. Since the transferred residual toner stays in the cleaning unit 6 and the transferred residual toner has leaked from the cleaning unit 6, it is considered that toner leakage has occurred.

[0189] Next, an image output experiment regarding "fixing failure" and "winding" will be described. Similar to the above experiment, the processing speed of the imaging device is 280 mm / sec, and its workload is 50 images per minute. The temperature setting of the fixing device 20 is set to two temperatures, i.e., 200 °C and 195 °C. Regarding the atmospheric environment for the experiment, the temperature is 23 °C, and the humidity is 50%.

[0190] First, an evaluation experiment of fixing failure will be described. Hammermill Premium Color Copy 60lb.Cover Paper (product name, Hammermill) with a basis weight of 162 g / m 2 and a sheet size of LTR is used as the recording material P.

[0191] After leaving the imaging device in a power-off state overnight and confirming that the temperature inside the device is sufficiently close to the atmospheric environment, a solid black image with an image coverage rate of 100% is printed on 550 sheets (i.e., 550 images) by single-sided continuous printing, and then it is confirmed whether fixing failure has occurred in the printed images.

[0192] Next, an evaluation experiment regarding winding will be described. CS-060F (product name, Canon Marketing Japan) with a basis weight of 60 g / m 2 and a sheet size of A4 is used as the recording material P. After leaving the imaging device in a power-off state overnight and confirming that the temperature inside the device is sufficiently close to the atmospheric environment, a solid black image with an image coverage rate of 100% is printed on 550 sheets (i.e., 1100 images) by double-sided continuous printing, and while performing the printing, it is confirmed whether a sheet jamming phenomenon has occurred in which the recording material is wound around the fixing device 20.

[0193] Regarding the imaging apparatuses of this embodiment and Comparative Examples 1 and 2, the set temperatures of the fixing device 20 and the results of each evaluation experiment are shown in Table 3.

[0194] Table 3

[0195]

[0196] According to this embodiment, during the evaluation experiments of fixing failure and winding, no fixing failure occurred at the set temperature of 200°C, but winding occurred. At the set temperature of 195°C, neither fixing failure nor winding failure occurred.

[0197] Meanwhile, according to Comparative Example 1, fixing failure occurred at the set temperature of 195°C, and winding occurred at the set temperature of 200°C. In addition, according to Comparative Example 2, fixing failure occurred at the set temperature of 195°C, and winding occurred at the set temperature of 200°C.

[0198] Next, the achieved effects will be described based on the measured temperatures in the evaluation experiment of toner leakage. In the image output experiments of "fixing failure" and "winding", similar heat dissipation effects of this embodiment were achieved.

[0199] As already described above in the image output experiment of "toner leakage", according to this embodiment, the temperature reached by the fixing cover 33 is low, but according to Comparative Examples 1 and 2, the temperature reached by the fixing cover 33 is high. In a state where the temperature reached by the fixing cover 33 is high, the detected temperature of the thermistor 34 becomes high. Therefore, if the temperature of the heating roller 30 is controlled to achieve the same detected temperature in this state, the temperature of the heating roller 30 will become too low.

[0200] In the image output experiments of Comparative Examples 1 and 2 where such a heat dissipation state was achieved, in a state where the set temperature was set to 195°C, it was considered that the temperature of the heating roller 30 had dropped to the level where fixing failure occurred in a state with a lower temperature due to temperature fluctuations accompanying the temperature control of the heating roller 30.

[0201] If the set temperature of the fixing device 20 in Comparative Examples 1 and 2 is set to a high temperature of 200°C to suppress the occurrence of fixing failure, adverse effects have occurred due to the excessive fixing temperature in a state where the temperature of the fixing cover 33 is low. That is, according to this embodiment, by selecting the set temperature of 195°C, the temperature can be set such that neither fixing failure nor winding occurs, while according to Comparative Examples 1 and 2, no temperature setting can prevent the occurrence of these two defects.

[0202] As described above, by tilting the flat portion B of the fixing cover 33 from the vertical orientation and arranging the first wall portion C of the exhaust heat pipe 51 adjacent to the flat portion B, a large amount of heat can be discharged from the fixing device 20 while increasing the amount of air flowing through the exhaust heat pipe 51. Therefore, the amount of heat conducted from the fixing device 20 to the cleaning unit 6 can be further reduced, and heat can be effectively discharged with a small-sized configuration. In other words, the heat insulation performance against the heat from the fixing device 20 can be improved.

[0203] Embodiment 2

[0204] Next, Embodiment 2 of the present invention will be described. Embodiment 2 employs an exhaust heat pipe 151 corresponding to the shape of the fixing cover 133, which is different from that of Embodiment 1. Therefore, the configurations similar to those in Embodiment 1 are either not shown or denoted by the same reference numerals.

[0205] Figure 10 is a schematic cross-sectional view showing the vicinity of the exhaust heat pipe 151 according to Embodiment 2. As Figure 10 shown, the fixing cover 133 includes an arcuate portion 133a that is 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 (e.g., polycarbonate) having excellent heat resistance and electrical insulation properties. The arcuate portion 133a is arranged at a position that is 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 heat pipe 151 serving as a pipe includes an arcuate portion 151a located upstream of the fixing cover 133 in the conveyance direction CD and a second wall portion D. The arcuate portion 151a serving as the first wall portion is arranged at a position that is approximately uniformly separated from the arcuate portion 133a by 1.5 mm so as to cover the arcuate portion 133a of the fixing cover 133. That is, the arcuate portion 133a serving as the opposing surface faces the arcuate portion 151a and extends along the arcuate portion 151a.

[0206] The arcuate 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 arcuate portion 151a is inclined with respect to the second wall portion D.

[0207] Figure 11A is a perspective view of the exhaust heat pipe 151 according to Embodiment 2, and Figure 11B is a front view of the exhaust heat pipe 151. Figure 11C is a plan view of the exhaust heat pipe 151, and Figure 11DIt is a side view of the exhaust heat pipe 151. The effects according to this embodiment are similar to those of Embodiment 1, and it is possible to suppress the accumulation of the transfer residual toner stored inside the cleaning unit 6 due to the heat generated by the fixing device 20, and it is possible to suppress the leakage of the transfer residual toner from the cleaning unit 6. These effects are achieved by arranging the arc portion 151a of the exhaust heat pipe 151 adjacent to the arc portion 133a of the fixing cover 133. Thus, by discharging a larger amount of heat of the fixing device 20 while increasing the amount of air flowing through the exhaust heat pipe 151, the heat conducted to the cleaning unit 6 can be further reduced.

[0208] The secondary effects are also similar to those of Embodiment 1, so that it is possible to suppress the occurrence of fixing failures (e.g., blister images and cold offset) caused by the winding of the recording material P or insufficient fixing temperature due to the usage state of the image forming apparatus A. By arranging the arc portion 151a of the exhaust heat pipe 151 adjacent to the arc portion 133a of the fixing cover 133, the effect of reducing the temperature change of the fixing cover 133 due to the usage state of the image forming apparatus A is achieved.

[0209] Based on these effects, compared with Embodiment 1, the amount of air flowing through the exhaust heat pipe 151 can be higher, so that better effects can be achieved. However, the shape of the exhaust heat pipe 151 becomes complicated.

[0210] As described above, according to this embodiment, by adopting the exhaust heat pipe 151 different from that of Embodiment 1 and corresponding to the shape of the fixing cover 133, the effects similar to those of Embodiment 1 can be effectively achieved.

[0211] Embodiment 3

[0212] Next, Embodiment 3 of the present invention will be described. In this Embodiment 3, an exhaust heat pipe 251 with further enhanced exhaust heat efficiency compared to Embodiment 1 is adopted. Therefore, the configurations similar to those of Embodiment 1 are either not shown or denoted by the same reference numerals.

[0213] Figure 12 It is a schematic cross-sectional view showing the vicinity of the exhaust heat pipe 251 according to Embodiment 3. Figure 13A It is a perspective view showing the exhaust heat pipe 251 according to Embodiment 3, and FIG. 13b is a front view of the exhaust heat pipe 251. Figure 13C It is a plan view of the exhaust heat pipe 251, and Figure 13D It is a side view of the exhaust heat pipe 251. Figure 14A It is a perspective view showing the state where the exhaust heat fin 53 according to Embodiment 3 is assembled to the main body portion 251e of the exhaust heat pipe 251, and Figure 14B It is a side view showing the state where the exhaust heat fin 53 is assembled to the main body portion 251e of the exhaust heat pipe 251.

[0214] As Figures 13A to 14B shown, a plurality of (three in this embodiment) long holes 251b are arranged on a main body portion 251e of a heat exhaust duct 251 serving as a pipe. The long holes extend in a width direction W and are aligned in a vertical direction. Except for the long holes 251b, the main body portion 251e serving as a first member has a shape similar to that of the heat exhaust duct 51 of Embodiment 1 and forms an air passage AP. The heat exhaust duct 251 is constituted by assembling a heat exhaust fin 53 serving as a second member to the main body portion 251e.

[0215] The heat exhaust fin 53 is formed of a zinc chromate steel plate (which is a metallic material) having a substantially V-shaped cross section and includes an upper surface 53a and side surfaces 53b that are bent and extend downward from the upper surface 53a. The side surfaces 53b serving as first wall portions face the fixing device 20. A plurality of (three in this embodiment) protruding portions 53c protruding upstream in a conveyance direction CD are arranged on the side surfaces 53b. In other words, the plurality of protruding portions 53c protrude toward the air passage AP. Further, the plurality of protruding portions 53c extend in a direction intersecting with the width direction W (which is a longitudinal direction of the heat exhaust duct 251). Each protruding portion 53c extends in the width direction W so as to correspond to the long hole 251b.

[0216] After the main body portion 251e has been attached to a scanner bracket 42 of a main body frame 43 by sliding in a thrust direction (i.e., the width direction W), the heat exhaust fin 53 is assembled to the scanner bracket 42. In this state, as Figure 12 shown, the main body portion 251e and the heat exhaust fin 53 sandwich the scanner bracket 42. In this state, the main body portion 251e and the heat exhaust fin 53 are fixed to the scanner bracket 42 using fixing screws. In this state, the protruding portions 53c of the heat exhaust fin 53 pass through the long holes 251b and protrude to the inside of the heat exhaust duct 251.

[0217] By widening a surface area of a member in contact with air flowing through the heat exhaust duct 251, the heat exhaust fin 53 achieves an effect of realizing more efficient heat exhaust. In other words, the plurality of protruding portions 53c of the heat exhaust fin 53 have surface roughness for increasing the surface area of the member in contact with air passing through the air passage AP in the heat exhaust duct 251. Thereby, the contact area between the heat exhaust duct 251 and air can be increased to enhance a cooling effect. Therefore, the heat of the fixing device 20 can be discharged more effectively, and the heat conducted to the cleaning unit 6 can be further reduced.

[0218] The effects according to this embodiment are similar to those of Embodiment 1, enabling suppression of the accumulation of transfer residual toner stored inside the cleaning unit 6 due to the heat generated in the fixing device 20 and preventing the leakage of transfer residual toner from the cleaning unit 6.

[0219] The secondary effects are also similar to those of Embodiment 1, enabling suppression of the occurrence of fixing failures (such as blister images and cold offset) caused by the winding of the recording material P or insufficient fixing temperature due to the usage state of the imaging device A.

[0220] Based on these effects, compared with Embodiment 1, heat dissipation through the air flowing in the heat dissipation duct 251 can be performed more effectively, thereby achieving better effects. However, since the heat dissipation fins 53 are attached to the main body portion 251e, the shape of the heat dissipation duct 251 becomes complex.

[0221] As described above, according to this embodiment, a heat dissipation duct 251 with higher heat dissipation efficiency than that of Embodiment 1 can be provided. In other words, the heat insulation performance against the heat from the fixing device 20 can be improved.

[0222] Embodiment 4

[0223] Next, Embodiment 4 of the present invention will be described. In this Embodiment 4, a heat dissipation duct 351 with further enhanced heat dissipation efficiency compared to Embodiment 1 is employed. Therefore, the structures similar to those of Embodiment 1 are either not shown or denoted by the same reference numerals.

[0224] Figure 15 is a schematic cross-sectional view showing the vicinity of the heat dissipation duct 351 according to Embodiment 4. Figure 16A is a perspective view of the heat dissipation duct 351 according to Embodiment 4, and Figure 16B is a front view of the heat dissipation duct 351. Figure 16C is a plan view of the heat dissipation duct 351, and Figure 16D is a side view of the heat dissipation duct 351.

[0225] As Figures 15 to 16DAs shown, the heat exhaust duct 351 serving as a pipe includes 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. In addition, the heat exhaust duct 351 is configured to form two spaces (i.e., air channels) through which air is blown within the heat exhaust duct 351. That is, the heat exhaust duct 351 is bent to form a first air channel SP1 on the downstream side (i.e., closer to the fixing device 20) in the conveyance direction CD (which is the sheet conveyance direction), and a second air channel SP2 on the upstream side in the conveyance direction CD (i.e., closer to the cleaning unit 6). In other words, the partition wall 351f of the heat exhaust duct 351 divides the air channel AP into a first air channel SP1 formed by the first wall portion C and a second air channel SP2 formed by the second wall portion D.

[0226] The heat exhaust duct 351 is assembled to the scanner bracket 42, and the second air channel SP2 is a space defined by the scanner bracket 42 and the heat exhaust duct 351. The air generated by the heat exhaust fan 50 passes through the first air channel SP1 and the second air channel SP2.

[0227] By adopting such a configuration, the effect of increasing the temperature difference of the heat exhaust duct 351 by extending the length of the heat exhaust duct 351 from the fixing cover 33 side to the cleaning unit 6 side can be achieved. In addition, by dividing the air flowing within the heat exhaust duct 351 into two parts, even if the temperature of the air flowing through the first air channel SP1 near the fixing cover 33 increases due to heat exhaust, the temperature of the air flowing through the second air channel SP2 near the cleaning unit 6 is not likely to increase. Thus, more heat of the fixing device 20 can be discharged, and the heat conducted to the cleaning unit 6 can be further reduced.

[0228] The effect of this embodiment is similar to the effect of Embodiment 1, such that the aggregation of the transferred residual toner stored inside the cleaning unit 6 due to the heat generated in the fixing device 20 can be suppressed, and the leakage of the transferred residual toner from the cleaning unit 6 can be prevented.

[0229] The secondary effect is also similar to the secondary effect of Embodiment 1, such that the occurrence of fixing failures (e.g., blister images and cold offset) due to the winding of the recording material P or insufficient fixing temperature according to the usage state of the imaging device A can be suppressed.

[0230] Based on these effects, compared with Embodiment 1, heat exhaust through the air flowing in the heat exhaust duct 351 can be performed more effectively, thereby achieving better effects. However, since the first air channel SP1 and the second air channel SP2 are formed by the heat exhaust duct 351, the shape of the heat exhaust duct becomes complex.

[0231] As described above, according to this embodiment, a heat exhaust pipe 351 with a higher heat exhaust efficiency than that of Embodiment 1 can be provided. In other words, the heat insulation performance against the heat from the fixing device 20 can be improved.

[0232] Embodiment 5

[0233] Next, Embodiment 5 of the present invention will be described. Embodiment 5 employs a shape different from that of the first wall portion C of the heat exhaust pipe 51 according to Embodiment 1. Therefore, the configurations similar to those in Embodiment 1 are either not shown or denoted by the same reference numerals.

[0234] Figure 17A is a perspective view of the heat exhaust pipe 451 according to Embodiment 5, and Figure 17B is a front view of the heat exhaust pipe 451. Figure 17C is a plan view of the heat exhaust pipe 451, and Figure 17D is a side view of the heat exhaust pipe 451.

[0235] As Figures 17A to 17D shown, the first wall portion C of the heat exhaust pipe 451 serving as a pipe according to Embodiment 5 is formed in a curved shape along the Figure 6 shape of the fixing cover 33 shown. That is, the first wall portion C is formed to face the fixing cover 33 and is disposed at a position separated by a substantially uniform distance from the surface of the planar portion B including the fixing cover 33. Thus, as in Embodiment 2, the amount of air flowing through the heat exhaust pipe 451 can be increased. Therefore, effects similar to those of Embodiments 1 and 2 can be achieved.

[0236] Embodiment 6

[0237] Next, Embodiment 6 of the present invention will be described. Instead of the heat dissipation fins 53 of Embodiment 3,

[0238] Embodiment 6 includes a protruding portion 551b disposed on the heat exhaust pipe 551. Therefore, the configurations similar to those in Embodiment 3 are either not shown or denoted by the same reference numerals.

[0239] Figure 18A is a perspective view of the heat exhaust pipe 551 according to Embodiment 6, and Figure 18B is a front view of the heat exhaust pipe 551. Figure 18C is a plan view of the heat exhaust pipe 551, and Figure 18D is a side view showing the heat exhaust pipe 551.

[0240] As Figures 18A to 18DAs shown, the exhaust heat pipe 551, which is a pipe made of a metal material, is provided with a plurality of (three in this embodiment) protruding portions 551b that protrude toward the exhaust heat pipe 551. The protruding portions 551b are formed by drawing the downstream-side surface of the exhaust heat pipe 551 in the conveyance direction CD thereof, and they extend in the width direction W. Similar to the exhaust heat fins 53 of Embodiment 3, the protruding portions 551b increase the surface area of the member that contacts the air flowing in the exhaust heat pipe 551. Therefore, an effect similar to that of Embodiment 3 can be achieved.

[0241] Embodiment 7

[0242] Next, Embodiment 7 of the present invention will be described. Instead of the heat dissipation fins 53 of Embodiment 3, Embodiment 7 includes exhaust heat fins 653 arranged on the upstream side in the conveyance direction CD of the main body portion 651e. Therefore, the configurations similar to those of Embodiment 3 are either not shown or denoted by the same reference numerals.

[0243] Figure 19A is a perspective view of the exhaust heat pipe 651 according to Embodiment 7, and Figure 19B is a front view of the exhaust heat pipe 651. Figure 19C is a plan view of the exhaust heat pipe 651, and Figure 19D is a side view of the exhaust heat pipe 651. Figure 20A is a perspective view of the state in which the exhaust heat fins 653 according to Embodiment 7 are assembled to the main body portion 651e, and Figure 20B is a side view showing the state in which the exhaust heat fins 653 are assembled to the main body portion 651e. By assembling the exhaust heat fins 653 to the main body portion 651e, the exhaust heat pipe 651 serving as a pipe is formed.

[0244] As Figures 19A to 20B shown, a plurality of (three in this embodiment) long holes 651b are arranged on the main body portion 651e of the exhaust heat pipe 651, and the long holes extend in the width direction W and are aligned in the vertical direction. Except for the long holes 651b, the main body portion 651e serving as the first member has a shape similar to that of the exhaust heat pipe 51 of Embodiment 1. The exhaust heat fins 653 serving as the second member are made of a zinc chromate steel plate (which is a metal material). A plurality of (three in this embodiment) protruding portions 653c that protrude toward the downstream side in the conveyance direction CD are arranged on the side surface of the exhaust heat fins 653. Each protruding portion 653c extends in the width direction W in a manner corresponding to the long holes 651b.

[0245] As described above, after the main body portion 651e has been assembled to the scanner holder 42 of the main body frame 43 by sliding in the thrust direction (i.e., the width direction W), the heat dissipation fins 653 are assembled to the scanner holder 42. In this state, the heat dissipation fins 653 are attached to the main body portion 651e from the upstream side in the transport direction CD. In this state, the protruding portion 653c of the heat dissipation fins 653 passes through the long hole 651b and protrudes into the internal space of the heat exhaust duct 651.

[0246] Similar to Embodiments 3 and 6, by increasing the surface area of the member in contact with the air flowing in the heat exhaust duct 651, the heat dissipation fins 653 achieve the effect of realizing more efficient heat exhaust. Therefore, this embodiment exhibits similar effects to Embodiments 3 and 6.

[0247] According to this embodiment, the protruding portion 653c is disposed on one side of the surface of the heat exhaust duct 651 opposite to the cleaning unit 6 (i.e., the second wall portion), while according to Embodiment 3, the protruding portion 53c is disposed on one side of the surface of the heat exhaust duct 651 opposite to the fixing device 20 (i.e., the first wall portion). That is, the plurality of protruding portions protruding toward the air passage AP can be disposed on either the first wall portion or the second wall portion of the heat exhaust duct.

[0248] Embodiment 8

[0249] Next, Embodiment 8 of the present invention will be described. Instead of the protruding portion 551b of Embodiment 6, Embodiment 8 includes a protruding portion 751b disposed on the heat exhaust duct 751. Therefore, the structure similar to that of Embodiment 6 is either not shown or denoted by the same reference numerals.

[0250] Figure 21A is a perspective view of the heat exhaust duct 751 according to Embodiment 8, and Figure 21B is a front view of the heat exhaust duct 751. Figure 21C is a plan view of the heat exhaust duct 751, and Figure 21D is a side view of the heat exhaust duct 751.

[0251] As Figures 21A to 21DAs shown, the heat exhaust pipe 751, which is a pipe made of a metallic material, is provided with a plurality (three in accordance with this embodiment) of protruding portions 751b that protrude toward the inner space of the heat exhaust pipe 751. The protruding portions 751b are formed by drawing the surface on the upstream side in the conveyance direction CD of the heat exhaust pipe 751 and extend in the width direction W. Similar to the heat exhaust fins 53 of Embodiment 3, the protruding portions 751b enable an increase in the surface area of the member that contacts the air flowing through the heat exhaust pipe 751. In other words, the plurality of protruding portions 751b of the heat exhaust pipe 751 have a surface roughness that is set to increase the surface area of the member that contacts the air flowing through the air passage AP in the heat exhaust pipe 751. Thereby, the contact area between the heat exhaust pipe 751 and the air can be increased, and the cooling effect can be enhanced. Therefore, effects similar to those of Embodiments 3 and 6 can be exhibited.

[0252] Embodiment 9

[0253] Next, Embodiment 9 of the present invention will be described. Instead of the heat exhaust pipe 351 of Embodiment 4, Embodiment 9 includes a heat exhaust pipe 851 composed of two members. Therefore, configurations similar to those of Embodiment 4 are either not shown or denoted by the same reference numerals.

[0254] Figure 22A is a perspective view of the heat exhaust pipe 851 according to Embodiment 9, and Figure 22B is a front view of the heat exhaust pipe 851. Figure 22C is a plan view of the heat exhaust pipe 851, and Figure 22D is a side view of the heat exhaust pipe 851.

[0255] As Figures 22A to 22D shown, the heat exhaust pipe 851, which is a pipe according to Embodiment 9, includes a first member 851a and a second member 851b. The first member 851a and the second member 851b are assembled to each other and integrally fixed by fixing screws. The first member 851a includes a first wall portion C facing the fixing device 20. The second member 851b includes a second wall portion D facing the cleaning unit 6 and a partition wall 851f.

[0256] The exhaust heat pipe 851 is formed to define two spaces (i.e., air passages) through which air flows within the exhaust heat pipe 851. That is, the exhaust heat pipe 851 is bent such that a first air passage SP1 is formed on the downstream side in the conveyance direction CD (i.e., closer to the fixing device 20), and a second air passage SP2 is formed on the upstream side in the conveyance direction CD (i.e., closer to the cleaning unit 6). In other words, the partition wall 851f of the second member 851b divides the air passage AP into the first air passage SP1 formed between the first wall portion C and the second air passage SP2 formed between the second wall portion D.

[0257] Therefore, although there is a disadvantage of requiring two members, there are the following advantages: two spaces can be provided in a more airtight manner (i.e., less air escapes from the exhaust heat pipe 851), and air can flow through these two spaces within the exhaust heat pipe 851. Thus, an effect similar to that of Embodiment 4 can be achieved.

[0258] According to the above-described Embodiments 5 to 9, while discharging more heat from the fixing device 20, the heat conducted to the cleaning unit 6 can be further reduced by the air flowing within the exhaust heat pipe, so that heat can be effectively discharged with a small-sized configuration. That is, the heat insulation performance against the heat from the fixing device 20 can be improved.

[0259] Embodiment 10

[0260] Next, Embodiment 10 of the present invention will be described. Embodiment 10 is designed to have improved conveyance performance of the recording material P compared to Embodiment 1. Therefore, the configurations similar to those in Embodiment 1 are either not shown or denoted by the same reference numerals. Regarding the configuration of the image forming apparatus of Embodiment 10, the positional relationship among the exhaust heat pipe, the pre-fixing guide 32, and the fixing cover is different from that in Embodiment 1, while other configurations are similar to those in Embodiment 1. Thus, the configurations identical to those in Embodiment 1 will not be described.

[0261] Exhaust heat pipe

[0262] Figure 23 is a schematic cross-sectional view near the exhaust heat pipe 951 according to Embodiment 10. In the exhaust heat pipe 951 according to the present embodiment, the positional relationship between the first wall portion C of the exhaust heat pipe 951 adjacent to the flat portion B of the fixing cover 933 and the flat portion B of the fixing cover 933 is different from that in Embodiment 1.

[0263] According to the present embodiment, as Figure 23As shown, a first wall portion C of the exhaust heat pipe 951 adjacent to a planar portion B of the fixing cover 933 includes an end portion 951d formed as a free end. Further, the planar portion B of the fixing cover 933 includes an end portion 933d formed as a free end. The end portion 933d is an upstream end portion of the fixing cover 933 in the conveyance direction CD. The first wall portion C is arranged not to cross a straight line LN1 passing through the end portion 933d and extending in the vertical direction. That is, compared with the straight line LN1, the end portion 951d of the first wall portion C is arranged downstream in the conveyance direction CD.

[0264] The distance between the planar portion B of the fixing cover 933 and the first wall portion C of the exhaust heat pipe 951 adjacent to the planar portion B of the fixing cover 933 is 3.0 mm or less. More specifically, the distance between the planar portion B and the first wall portion C at the closest portion is 1.0 mm, and the distance between them at the farthest portion is 2.5 mm. Further, by arranging the exhaust heat pipe 951 formed of a metal plate at the boundary between the fixing device 20 and the cleaning unit 6, heat of the fixing device 20 is prevented from being directly conducted to the cleaning unit 6. The distance between a second wall portion D of the exhaust heat pipe 951 adjacent to a surface 6b of a container 6a of the cleaning unit 6 and the surface 6b is 2.0 mm.

[0265] Effects of Embodiment 10

[0266] The effects of this embodiment will be described. According to this embodiment, the first wall portion C of the exhaust heat pipe 951 is arranged not to cross the straight line LN1 passing through the end portion 933d of the planar portion B. That is, the planar portion B of the fixing cover 933 extends directly below the end portion 951d of the first wall portion C of the exhaust heat pipe 951. In other words, the planar portion B of the fixing cover 933 is interposed between a conveyance path P10 formed between a transfer nip portion and a fixing nip portion and the end portion 951d of the first wall portion C of the exhaust heat pipe 951, and the end portion 951d is not directly opposed to the conveyance path P10. The fixing cover 933 is made of a resin material (e.g., polycarbonate) having excellent electrical insulation properties. Thereby, stable conveyance performance of the recording material P can be achieved, and the recording material P is not affected by the electrostatic attraction acting on the exhaust heat pipe 951 serving as a pipe and does not experience defects such as paper wrinkling.

[0267] This is related to the recording material P being supplied with charge and thus being charged when passing through the transfer roller 5. When a grounded object approaches the recording material P being charged, an electrostatic attraction acts on the object from the recording material P. However, even when, as in this embodiment, the exhaust heat pipe 951 is grounded to the main body frame 43 via the scanner bracket 42, by arranging the first wall portion C of the exhaust heat pipe 951 so as not to cross the straight line LN1, the effect of suppressing the electrostatic attraction from the recording material P acting on the exhaust heat pipe 951 can be achieved.

[0268] Confirmation of the effects of Embodiment 10

[0269] Next, the results of the transfer performance experiment of the recording material P will be described to confirm the effects of this embodiment. The effects are confirmed using the exhaust heat pipe 951 according to this embodiment and the exhaust heat pipe 51 according to Embodiment 1 as a comparative example.

[0270] The method of the transfer performance experiment of the recording material P will be described. CS-068 standard paper (product name, Canon Marketing Japan) with a basis weight of 68 g / m 2 and a sheet size of A4 is used as the recording material.

[0271] According to the imaging device used in the experiment, the processing speed during the experiment is 280 mm / sec, and its workload is 50 images per minute. The set temperature of the fixing device is 200°C. Regarding the atmospheric environment in which the experiment is conducted, the temperature is 15°C, and the humidity is 10%.

[0272] After leaving the imaging device and the recording material P in the above atmospheric environment for two nights, printing is continuously performed on 200 sheets of the recording material by single-sided continuous printing, and the occurrence of paper wrinkling is confirmed.

[0273] The results obtained from the transfer performance experiment of the recording material P are shown in Table 4.

[0274] Table 4

[0275] Occurrence of paper wrinkling Example 10 0 / 200 Example 1 18 / 200

[0276] When using the exhaust heat pipe 951 according to this embodiment, no paper wrinkling of the recording material P occurred, and good results were achieved. At the same time, when using the exhaust heat pipe 951 of Embodiment 1, paper wrinkling of the recording material P occurred. That is, by adopting the exhaust heat pipe 951 of this embodiment, the transfer performance of the recording material P is improved, and the occurrence of paper wrinkling is suppressed.

[0277] As described above, by arranging the first wall portion C of the exhaust heat pipe 951 so as not to cross the straight line LN1, the influence of the electrostatic attraction force of the recording material P acting on the exhaust heat pipe 951 can be suppressed. Thereby, while enhancing the heat insulation performance against the heat from the fixing device 20, conveyance failures such as paper wrinkling can be suppressed, and the conveyance performance can be improved.

[0278] Example 11

[0279] Next, Example 11 of the present invention will be described. In Example 11, the shapes of the fixing cover 933 and the exhaust heat pipe 951 of Example 10 are changed. Therefore, the configurations similar to those in Example 3 are either not shown or denoted by the same reference numerals.

[0280] Exhaust Heat Pipe and Fixing Cover

[0281] Figure 24 is a schematic cross-sectional view near the exhaust heat pipe 1051 according to Example 11. As Figure 24 shown, the angle formed by the first wall portion C and the upper surface 1051a of the exhaust heat pipe 1051 is 90°. The planar portion B of the fixing cover 1033 according to the present embodiment is bent, and the vicinity of the end portion 1033d extends upstream in the conveyance direction CD. In other words, the planar portion B is arranged to cover the end portion 1051d of the first wall portion C of the exhaust heat pipe 1051 serving as a pipe. The fixing cover 1033 is formed of a resin material (e.g., polycarbonate) having excellent electrical insulation properties. Even with the configuration according to the present embodiment, the influence of the electrostatic attraction force acting on the exhaust heat pipe 1051 from the recording material P can be suppressed. Thereby, while enhancing the heat insulation performance against the heat from the fixing device 20, conveyance failures such as paper wrinkling can be suppressed, and the conveyance performance can be improved.

[0282] Example 12

[0283] Next, Example 12 of the present invention will be described. Compared with Example 1, Example 12 suppresses the temperature rise of the exposure unit 3. Therefore, the configurations similar to those in Example 1 are either not shown or denoted by the same reference numerals. Figure 25 is a schematic cross-sectional view of the image forming apparatus A according to Example 12.

[0284] As Figure 25As shown, the scanner bracket 42 supports the exposure unit 3 that irradiates the photosensitive drum 1 with a laser. In addition, the heat exhaust duct 1151 that serves as a pipe can be installed to the scanner bracket 42 by sliding in the thrust direction (i.e., the width direction W). That is, the heat exhaust from the fixing device 20 introduced into the heat exhaust duct 1151 can flow toward the exposure unit 3 through the scanner bracket 42. In that case, the temperature of the exposure unit 3 may increase, which may cause abnormal exposure operations, such as the accuracy of the exposed image not meeting the standard.

[0285] The scanner bracket 42 according to the present embodiment is a part of the main body frame 43 and is formed of a metal material (e.g., zinc chromate steel plate) to achieve high rigidity. As described, when the scanner bracket 42 is made of a metal material with a higher thermal conductivity than resin, the heat conducted from the heat exhaust duct 1151 to the exposure unit 3 also increases.

[0286] Heat exhaust duct

[0287] The heat exhaust duct 1151 according to the present embodiment is characterized in that when exhausting the heat exhaust of the fixing device 20 to the outside, the heat conducted through the scanner bracket 42 is suppressed. The heat exhaust duct 1151 according to the present embodiment is attached to the scanner bracket 42 in a state where the heat insulation member 55 is inserted between the heat exhaust duct 1151 and the scanner bracket 42.

[0288] Figure 26A is a perspective view of the heat exhaust duct 1151 according to Embodiment 12, and Figure 26B is a front view of the heat exhaust duct 1151. Figure 26C is a plan view of the heat exhaust duct 1151, and Figure 26D is a side view of the heat exhaust duct 1151.

[0289] As Figures 26A to 26D shown, the heat insulation member 55 according to the present embodiment uses polycarbonate with a relatively low thermal conductivity and is attached to the heat exhaust duct 1151 using double-sided tape. The heat insulation member 55 has a lower thermal conductivity than the heat exhaust duct 1151 formed of a metal material. Polycarbonate is a resin material, and the heat insulation member 55 can be made of a resin material other than polycarbonate. The heat insulation member 55 extends in the width direction W, and its length is preferably long in the width direction W as long as it does not prevent the installation of the heat exhaust duct 1151 on the scanner bracket 42. In the present embodiment, NS5000 (product name, Nitto Denko Corporation) is used as the double-sided tape. The heat exhaust duct 1151 attached with the heat insulation member 55 is installed to the scanner bracket 42 using screws.

[0290] Effects of Embodiment 12

[0291] The effects of this embodiment will be described. By arranging the heat insulation member 55 between the exhaust heat pipe 1151 and the scanner bracket 42 as in this embodiment, heat conduction from the exhaust heat pipe 1151 to the scanner bracket 42 can be suppressed.

[0292] The effect of suppressing the temperature rise of the exposure unit 3 can also be achieved by arranging a heat insulation member between the scanner bracket 42 and the exposure unit 3. However, when the temperature of the scanner bracket 42 rises, the ambient temperature near the exposure unit 3 rises, which may cause the temperature of the exposure unit 3 to rise. Therefore, the structure for suppressing heat conduction from the exhaust heat pipe 1151 to the scanner bracket 42 as in this embodiment has a better effect of suppressing the temperature rise of the exposure unit 3.

[0293] Confirmation of the effects of Embodiment 12

[0294] Next, the results of the temperature rise experiment of the exposure unit 3 will be described to confirm the effects of this embodiment. The exhaust heat pipe 1151 according to this embodiment and the exhaust heat pipe 51 according to Embodiment 1 as a comparative example were used to confirm the effects.

[0295] The method of the temperature rise experiment will be described. Canon Red Label (product name, Canon E.U.) with a basis weight of 80 g / m 2 and a sheet size of A4 was used as the recording material. According to the imaging device used in the experiment, the processing speed during the experiment was 280 mm / sec, and its workload was 50 images per minute. The set temperature of the fixing device 20 was 200 °C. Regarding the atmospheric environment for the experiment, the temperature was 32.5 °C, and the humidity was 80%.

[0296] After leaving the imaging device A powered off overnight and confirming that the temperature inside the device was sufficiently close to the atmospheric environment, a horizontal line image with an image coverage rate of 2% was printed on 500 sheets (i.e., 1,000 images) by double-sided continuous printing, and then, the surface temperature of the scanner bracket 42 and the surface temperature of the exposure unit 3 were confirmed. Thermocouples were brought into contact with the mounting portion of the scanner bracket 42 for attaching the exposure unit 3 and the polygon motor portion of the exposure unit 3 to measure the maximum temperature reached respectively.

[0297] The results of the temperatures measured by the temperature rise experiment are shown in Table 5.

[0298] Table 5

[0299] Surface temperature of the scanner support Surface temperature of the exposure unit Heat exhaust pipe of Example 12 40℃ 55℃ Heat exhaust pipe of Example 1 45℃ 60℃

[0300] When the exhaust heat pipe 1151 according to this embodiment is used, the surface temperature of the scanner bracket 42 is 40°C, and the surface temperature of the exposure unit 3 is 55°C. Meanwhile, when the exhaust heat pipe 51 of Embodiment 1 is used, the surface temperature of the scanner bracket 42 is 45°C, and the surface temperature of the exposure unit 3 is 60°C. That is to say, by adopting the exhaust heat pipe 1151 according to this embodiment, the temperature rise of the scanner bracket 42 can be suppressed, and the temperature rise of the exposure unit 3 can also be suppressed.

[0301] As described above, by arranging the heat insulation member 55 between the exhaust heat pipe 1151 and the scanner bracket 42, the heat conduction from the exhaust heat pipe 1151 to the scanner bracket 42 can be suppressed, and the temperature rise of the exposure unit 3 can be suppressed. In other words, the heat insulation performance against the heat from the fixing device 20 can be enhanced.

[0302] Embodiment 13

[0303] Next, Embodiment 13 of the present invention will be described. Compared with Embodiment 12, Embodiment 13 suppresses the temperature rise of the exposure unit 3 with a simpler structure. Therefore, the structure similar to that of Embodiment 12 is either not shown or denoted by the same reference numerals.

[0304] Figure 27 is a schematic cross-sectional view of the imaging device A according to Embodiment 13. As Figure 27 shown, the exhaust heat pipe 1251 according to this embodiment is characterized in that it is formed of a resin material having a lower thermal conductivity than a metal material. Figure 28A is a perspective view of the exhaust heat pipe 1251 according to Embodiment 13, and Figure 28B is a front view of the exhaust heat pipe 1251. Figure 28C is a plan view of the exhaust heat pipe 1251, and Figure 28D is a side view of the exhaust heat pipe 1251. The shape of the exhaust heat pipe 1251 can be any shape described in the foregoing embodiments.

[0305] In the above-mentioned Embodiment 12, the exhaust heat pipe 1251 and the scanner bracket 42 are made of a metal material having a high thermal conductivity. Therefore, by arranging a heat insulation member 55 having a low thermal conductivity between the exhaust heat pipe 1251 and the scanner bracket 42, the heat conduction from the exhaust heat pipe 1251 to the scanner bracket 42 is suppressed, and thereby the temperature rise of the exposure unit 3 is suppressed.

[0306] According to this embodiment, the exhaust heat pipe 1251 is formed of a resin material having a lower thermal conductivity than the scanner bracket 42 formed of a metal material. Thereby, the temperature rise of the exposure unit 3 can be suppressed. However, since the exhaust heat pipe 1251 is formed of a resin material, the effect of absorbing the heat of the fixing device 20 by the exhaust heat pipe 1251 and discharging the heat through the air flowing through the pipe is slightly weakened. In addition, the scanner bracket 42 forms a part of the main body frame 43, and in order to ensure high rigidity, it is preferable to form the exhaust heat pipe 1251 of a metal material such as a zinc chromate steel plate.

[0307] As described above, according to this embodiment, the exhaust heat pipe 1251 serving as a pipe is formed of a material having a low thermal conductivity, so that the temperature rise of the exposure unit 3 can be suppressed. Thereby, the temperature rise of the exposure unit 3 can be suppressed by a simple configuration without arranging a heat insulating member 55 between the exhaust heat pipe 1251 and the scanner bracket 42. In other words, the heat resistance performance against the heat from the fixing device 20 can be enhanced.

[0308] If rigidity can be ensured, the scanner bracket 42 can be formed of a resin material having a low thermal conductivity, or the exhaust heat pipe 1251 and the scanner bracket 42 can be formed of a resin material having a low thermal conductivity.

[0309] Embodiment 14

[0310] Next, Embodiment 14 of the present invention will be described. Compared with Embodiment 1, Embodiment 14 is designed to more effectively absorb the exhaust heat of the fixing device 20. Therefore, the configurations similar to those in Embodiment 1 are either not shown or denoted by the same reference numerals.

[0311] Figure 29 is a schematic cross-sectional view of the vicinity of the exhaust heat pipe 1351 according to Embodiment 14. Figure 30A is a front view of the exhaust heat pipe 1351 according to Embodiment 14, Figure 30B is a plan view of the exhaust heat pipe 1351, and Figure 30C is a side view of the exhaust heat pipe 1351. Figure 31A is a perspective view of the exhaust heat pipe 1351 according to Embodiment 14, and Figure 31B is another perspective view of the exhaust heat pipe 1351.

[0312] As Figures 29 to 31BAs shown, a plurality (three in accordance with the present embodiment) of duct vent holes 56 are formed in a first wall portion C of the heat exhaust duct 1351 serving as a duct, which faces the fixing cover 33. The duct vent holes 56 serving as a plurality of opening portions extend in the width direction W, are arranged in parallel in the vertical direction, and communicate with the air passage AP. Heat exhaust from the fixing device 20 can be effectively drawn into the heat exhaust duct 1351 through the duct vent holes 56, and the heat exhaust of the fixing device 20 can be effectively discharged to the outside of the apparatus.

[0313] Regarding the size of the openings of the duct vent holes 56 arranged in the first wall portion C of the heat exhaust duct 1351, the area ratio of the duct vent holes 56 to the first wall portion C is 19%. From the viewpoint of achieving the effects of the present embodiment, preferably, the area ratio of the duct vent holes 56 is 3% or more. The larger the area ratio of the duct vent holes 56, the better the effect of effectively discharging the heat exhaust from the fixing device 20 to the outside of the apparatus.

[0314] Therefore, by effectively discharging the heat exhaust from the fixing device 20 to the outside of the apparatus, the temperature rise inside the apparatus can be suppressed. In other words, by suppressing the temperature rise inside the apparatus, the temperature rise of the cleaning unit 6 and the exposure unit 3 can be suppressed.

[0315] In addition, as described in Embodiment 1, since the detected temperature of the thermistor 34 for achieving optimal fixing of the toner image to the recording material P varies between the state where the fixing cover 33 is cooled and the state where the fixing cover 33 is heated, it is possible to increase the tolerance related to defects generated when the temperature of the heating roller 30 is high or defects generated when its temperature is low.

[0316] While the heat exhaust from the fixing device 20 increases, the discharge of the heat generated from the low-voltage power supply 45 through the vent holes 52 and the heat exhaust duct 1351 by discharging air using the heat exhaust fan 50 decreases. Therefore, the size of the duct vent holes 56 is preferably determined such that its area ratio with respect to the first wall portion C is less than 60%. Regarding the opening ratio, the size of the duct vent holes 56 (i.e., the opening ratio of the first wall portion C) is adjusted according to the characteristics of the imaging apparatus (for example, the level of heat exhaust discharged from the fixing device 20 as described above).

[0317] As described above, by forming the duct vent holes 56 in the heat exhaust duct 1351, the heat exhaust of the fixing device 20 can be more effectively absorbed into the heat exhaust duct 1351, and the temperature rise of the cleaning unit 6 and the exposure unit 3 can be suppressed. In other words, the heat insulation performance against the heat from the fixing device 20 can be enhanced.

[0318] According to this embodiment, the duct vent holes 56 serving as a plurality of opening portions are arranged only on the first wall portion C, but the present technology is not limited thereto. For example, the duct vent holes 56 may be arranged on the second wall portion D, or may be arranged on both the first wall portion C and the second wall portion D. That is, the duct vent holes 56 will be arranged on at least one of the first wall portion C and the second wall portion D.

[0319] Embodiment 15

[0320] Next, Embodiment 15 of the present invention will be described. Compared with Embodiment 1, Embodiment 15 is designed to suppress the temperature rise of the cleaning unit 6. Therefore, the structures similar to those in Embodiment 1 are either not shown or denoted by the same reference numerals.

[0321] In the case where the printing speed is increased compared with the imaging device of Embodiment 1, the calorific value of the fixing device 20 increases, and the cleaning unit 6 arranged close to the fixing device 20 and generating heat by friction with the photosensitive drum 1 is easily heated.

[0322] Heat exhaust duct

[0323] The heat exhaust duct 1451 serving as a duct according to this embodiment is characterized in that when exhausting heat from the fixing device 20 to the outside of the device, the heat flow to the cleaning unit 6 is suppressed. Similar to Embodiment 1, the heat exhaust duct 1451 according to this embodiment forms an air passage communicating from the electronic component side to the driving side, and effectively suppresses the heat exhaust of the fixing device 20 from being conducted to the cleaning unit 6. In addition, a heat insulating member 155 is arranged on the second wall portion D of the heat exhaust duct 1451 adjacent to the cleaning unit 6, whereby heat conduction to the cleaning unit 6 can be suppressed.

[0324] Figure 32 is a schematic cross-sectional view of the vicinity of the heat exhaust duct 1451 according to Embodiment 15. As Figure 32 shown, the heat insulating member 155 is attached to the second wall portion D of the heat exhaust duct 1451 according to this embodiment. Figure 33A is a perspective view of the heat exhaust duct 1451 and the heat insulating member 155 according to Embodiment 15, and Figure 33B is a front view of the heat exhaust duct 1451 and the heat insulating member 155.

[0325] Figure 33C is a plan view of the heat exhaust duct 1451 and the heat insulating member 155, and Figure 33D is a side view of the heat exhaust duct 1451 and the heat insulating member 55.

[0326] The heat insulation member 155 according to the present embodiment uses polycarbonate, which is a resin material, and is attached to the exhaust heat pipe 1451 by sliding in the thrust direction (i.e., the width direction W). In other words, the heat insulation member 155 has a lower thermal conductivity than the exhaust heat pipe 1451 formed of a metal material. Further, the exhaust heat pipe 1451 to which the heat insulation member 155 is attached is mounted to the scanner bracket 42 using screws.

[0327] Effect of Embodiment 15

[0328] The effects of the present embodiment will be described. By disposing the heat insulation member 155 on the second wall portion D of the exhaust heat pipe 1451 as in the present embodiment, heat conduction from the exhaust heat pipe 1451 to the cleaning unit 6 can be suppressed.

[0329] Confirmation of the Effect of Embodiment 15

[0330] Next, the results of the temperature rise experiment of the exposure unit 3 will be described to confirm the effects of the present embodiment. The exhaust heat pipe 1451 according to the present embodiment and the exhaust heat pipe 51 according to Embodiment 1 as a comparative example were used to confirm the effects.

[0331] The method of the temperature rise experiment will be described in detail. Canon RedLabel (product name, Canon E.U.) with a basis weight of 80 g / m 2 and a sheet size of A4 was used as the recording material.

[0332] In the imaging apparatus used for the experiment, the processing speed during the experiment was 320 mm / sec, and the workload was 55 images per minute. The set temperature of the fixing device was 215°C. For the atmospheric environment in which the experiment was conducted, the temperature was 32.5°C, and the humidity was 80%.

[0333] After leaving the imaging apparatus powered off overnight and confirming that the temperature inside the apparatus was sufficiently close to the atmospheric environment, horizontal line images with an image coverage of 2% were printed on 500 sheets (i.e., 1,000 images) by double-sided continuous printing, and then, the surface temperature of the cleaning unit 6 facing the exhaust heat pipe 1451 was confirmed.

[0334] The results of the temperatures measured by the temperature rise experiment are shown in Table 6.

[0335] Table 6

[0336] Surface temperature of the cleaning unit Heat exhaust pipe of Example 15 44℃ Heat exhaust pipe of Example 1 47℃

[0337] When using the exhaust heat pipe 1451 according to this embodiment, the surface temperature of the cleaning unit 6 is 44°C. Meanwhile, when using the exhaust heat pipe 51 of Embodiment 1, the surface temperature of the cleaning unit 6 is 47°C. That is to say, by adopting the exhaust heat pipe 1451 according to this embodiment, the temperature rise of the cleaning unit 6 can be suppressed.

[0338] As described, by arranging the heat insulation member 155 on the second wall portion D of the exhaust heat pipe 1451 adjacent to the cleaning unit 6, the temperature rise of the cleaning unit 6 can be further suppressed. In other words, the heat insulation performance against the heat from the fixing device 20 can be enhanced.

[0339] Embodiment 16

[0340] Next, Embodiment 16 of the present invention will be described. Compared with Embodiment 1, Embodiment 16 is designed to suppress the temperature rise of the cleaning unit 6 and the exposure unit 3. Therefore, the structures similar to those in Embodiment 1 are either not shown or denoted by the same reference numerals.

[0341] When the printing speed is increased, the calorific value of the fixing device 20 increases. Therefore, the exhaust heat quantity of the exhaust heat pipe 51 according to Embodiment 1 becomes excessive, and the influence of the temperature rise of the cleaning unit 6 and the exposure unit 3 may be excessive. In this case, by arranging the heat insulation member 255 on the fixing cover side of the exhaust heat pipe 51, the temperature rise of the cleaning unit 6 and the exposure unit 3 can be further suppressed.

[0342] Figure 34 is a schematic cross-sectional view of the vicinity of the exhaust heat pipe 51 according to Embodiment 16. As Figure 34 shown, the heat insulation member 255 is attached to the first wall portion C of the exhaust heat pipe 51 according to this embodiment adjacent to the fixing device 20. Figure 35A is a perspective view of the exhaust heat pipe 51 and the heat insulation member 255 according to Embodiment 16, and Figure 35B is a front view of the exhaust heat pipe 51. Figure 35C is a plan view of the exhaust heat pipe 51 and the heat insulation member 255, and Figure 35D is a side view of the exhaust heat pipe 51 and the heat insulation member 255.

[0343] The heat insulation member 255 according to this embodiment uses polycarbonate (which is a resin material with a relatively low thermal conductivity), and it is attached to the exhaust heat pipe 51 by sliding along the thrust direction (i.e., the width direction W). In other words, compared with the exhaust heat pipe 51 formed of a metal material, the heat insulation member 255 has a lower thermal conductivity. In addition, the exhaust heat pipe 51 to which the heat insulation member 255 is attached is installed on the scanner bracket 42 using screws.

[0344] By reducing the amount of heat exhausted from the fixing device 20 to the exhaust heat pipe 51, the heat exhausted from the fixing device 20 itself tends to decrease, and the temperature rise of the cleaning unit 6 and the exposure unit 3 can be suppressed. At the same time, the secondary effects described in Example 1 tend to weaken, and the temperature reached by the fixing cover 33 will increase. Therefore, from the perspective of performing preferred temperature control of the heating roller 30 in a state where the temperature reached by the fixing cover 33 is low and high (i.e., the detected temperature of the thermistor 34 is high and low), this may be disadvantageous.

[0345] As described above, by disposing the heat insulation member 255 on the first wall portion C of the exhaust heat pipe 51 near the fixing cover 33, the heat exhausted from the fixing device 20 through the exhaust heat pipe 51 can be reduced, and the temperature rise of the cleaning unit 6 and the exposure unit 3 can be suppressed. In other words, the heat insulation performance against the heat from the fixing device 20 can be enhanced.

[0346] In Example 15, the heat insulation member 155 is attached to the second wall portion D, and in Example 16, the heat insulation member 255 is attached to the first wall portion C. The heat insulation members 155 and 255 can also be attached to the first wall portion C and the second wall portion D. That is, a heat insulation member having a lower thermal conductivity than the exhaust heat pipe will be disposed on at least one of the first wall portion C and the second wall portion D of the exhaust heat pipe.

[0347] Example 17

[0348] Next, Example 17 of the present invention will be described. In Example 17, the shape of the exhaust heat pipe 951 of Example 10 is changed. Therefore, the configurations similar to those of Example 10 are either not shown or denoted by the same reference numerals.

[0349] Figure 36 is a schematic cross-sectional view near the exhaust heat pipe 1651 according to Example 17. Figure 37A is a perspective view of the exhaust heat pipe 1651 according to Example 17, and Figure 37B is a front view of the exhaust heat pipe 1651. Figure 37C is a plan view of the exhaust heat pipe 1651, and Figure 37D is a side view of the exhaust heat pipe 1651.

[0350] Compared with the shape of the exhaust heat pipe 51 of Example 1, the exhaust heat pipe 1651 used as the pipe in this embodiment is formed such that the first wall portion C near the fixing device 20 has a shorter length. The fixing cover 1633 is formed of a resin material (e.g., polycarbonate) having excellent electrical insulation properties. Therefore, similar to Example 10, this embodiment achieves stable conveyance performance without causing defects such as paper wrinkling and is not affected by the electrostatic attraction acting on the exhaust heat pipe 1651 from the recording material P.

[0351] That is, according to this embodiment, as Figure 36 shown, the first wall portion C of the exhaust heat pipe 1651 adjacent to the flat portion B of the fixing cover 1633 is arranged 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 of the straight line LN1 in the conveyance direction CD. In other words, the flat portion B is arranged to cover the end portion 1651d of the first wall portion C of the exhaust heat pipe 1651. Therefore, effects similar to those of Embodiments 10 and 11 can be achieved.

[0352] Embodiment 18

[0353] Next, Embodiment 18 of the present invention will be described. In Embodiment 18, the shape of the exhaust heat pipe 1151 in Embodiment 12 is changed. Therefore, the configurations similar to those in Embodiment 12 are either not shown or denoted by the same reference numerals.

[0354] Figure 38 is a schematic cross-sectional view near the exhaust heat pipe 2151. Figure 39A is a perspective view of the exhaust heat pipe 2151 and the heat insulating member 55 according to Embodiment 18, and Figure 39B is a front view of the exhaust heat pipe 2151. Figure 39C is a plan view of the exhaust heat pipe 2151 and the heat insulating member 55, and Figure 39D is a side view of the exhaust heat pipe 2151 and the heat insulating member 55.

[0355] As Figures 38 to 39D shown, the exhaust heat pipe 2151 according to this embodiment has a shape similar to that of the exhaust heat pipe in Comparative Example 1 shown in Figures 8A to 8D . In addition, a heat insulating member 55 similar to that in Embodiment 12 is assembled to the upper surface 2151a of the exhaust heat pipe 2151.

[0356] The exhaust heat pipe 2151 is attached to the scanner bracket 42 in a state where the heat insulating member 55 is inserted between the exhaust heat pipe 2151 and the scanner bracket 42. Thereby, heat conduction from the exhaust heat pipe 2151 to the scanner bracket 42 can be suppressed, and the temperature rise of the exposure unit 3 can be suppressed. Therefore, effects similar to those of Embodiment 12 can be achieved. The heat insulating member 55 can also be attached to the upper surface of the exhaust heat pipe 2251 in Comparative Example 2 shown in Figures 9A to 9D .

[0357] Embodiment 19

[0358] Next, Embodiment 19 of the present invention will be described. In Embodiment 19, the shape of the exhaust heat pipe 1451 in Embodiment 15 is changed. Therefore, the configurations similar to those in Embodiment 15 are either not shown or denoted by the same reference numerals.

[0359] Figure 40 It is a schematic cross-sectional view near the exhaust heat pipe 2151 according to Embodiment 19. Figure 41A It is a perspective view of the exhaust heat pipe 2151 and the heat insulation member 155 according to Embodiment 19, and Figure 41B It is a front view of the exhaust heat pipe 2151 and the heat insulation member 155. Figure 41C It is a plan view of the exhaust heat pipe 2151 and the heat insulation member 155, and Figure 41D It is a side view of the exhaust heat pipe 2151 and the heat insulation member 155.

[0360] As Figures 40 to 41D shown, the exhaust heat pipe 2151 according to the present embodiment has a shape similar to that of the exhaust heat pipe of Comparative Example 1 Figures 8A to 8D shown. A heat insulation member 155 similar to that of Embodiment 15 is assembled to the second wall portion D of the exhaust heat pipe 2151 near the cleaning unit 6. Thus, similar to Embodiment 15, heat conduction from the exhaust heat pipe 2151 to the cleaning unit 6 can be suppressed, and the temperature rise of the cleaning unit 6 can be suppressed. The heat insulation member 155 can also be attached to Figures 9A to 9D the second wall portion D of the exhaust heat pipe 2251 of Comparative Example 2

[0361] Embodiment 20

[0362] Next, Embodiment 20 of the present invention will be described. In Embodiment 20, the shape of the exhaust heat pipe 51 of Embodiment 16 is changed. Therefore, the structure similar to that of Embodiment 16 is either not shown or denoted by the same reference numerals.

[0363] Figure 42 It is a schematic cross-sectional view near the exhaust heat pipe 2151 according to Embodiment 20. Figure 43A It is a perspective view of the exhaust heat pipe 2151 and the heat insulation member 255 according to Embodiment 20, and Figure 43B It is a front view of the exhaust heat pipe 2151. Figure 43C It is a plan view of the exhaust heat pipe 2151 and the heat insulation member 255, and Figure 43D It is a side view of the exhaust heat pipe 2151 and the heat insulation member 255.

[0364] As Figures 42 to 43D shown, the exhaust heat pipe 2151 according to the present embodiment has a shape similar to that of the exhaust heat pipe of Comparative Example 1 Figures 8A to 8D shown. A heat insulation member 255 similar to that of Embodiment 16 is assembled to the first wall portion C of the exhaust heat pipe 2151 near the fixing device 20.

[0365] By assembling the heat insulation member 255 to the first wall portion C of the exhaust heat pipe 2151, the amount of heat exhausted from the fixing device 20 to the exhaust heat pipe 2151 can be reduced. Therefore, similar to Embodiment 16, the temperature rise of the cleaning unit 6 and the exposure unit 3 can be suppressed. The heat insulation member 255 can also be attached to Figures 9A to 9D the first wall portion C of the exhaust heat pipe 2251 of Comparative Example 2 shown.

[0366] Other embodiments

[0367] In Embodiment 3, the heat dissipation fins 53 are attached to the main body portion 651e having a shape substantially similar to that of Embodiment 1 from the downstream side in the conveyance direction CD, but the present technology is not limited thereto. For example, as in Figure 44A Variation 1 shown, the heat dissipation fins 53 can be attached to the main body portion 2151e having a shape similar to that of Figures 8A to 8D Comparative Example 1 shown from the downstream side in the conveyance direction CD. The exhaust heat pipe 1851A serving as a pipe is composed of the main body portion 2151e and the heat dissipation fins 53. Even in this case, an effect similar to that of Embodiment 3 can be exhibited. Further, the heat dissipation fins 53 can be attached to the exhaust heat pipe 2251 of Comparative Example 2 shown in Figures 9A to 9D from the downstream side in the conveyance direction CD.

[0368] As in Figure 44B Variation 2 shown, the heat dissipation fins 53 can also be attached to the main body portion 2151e having a shape similar to that of Figures 8A to 8D Comparative Example 1 shown from the upstream side in the conveyance direction CD. The exhaust heat pipe 1851B serving as a pipe is composed of the main body portion 2151e and the heat dissipation fins 53. Even in this case, an effect similar to that of Embodiment 3 can be exhibited. Further, the heat dissipation fins 53 can be attached to the exhaust heat pipe 2251 of Comparative Example 2 shown in Figures 9A to 9D from the upstream side in the conveyance direction CD.

[0369] Further, in Embodiment 6, the protruding portion 551b having a function similar to that of the heat dissipation fins 53 is arranged on the exhaust heat pipe 551 having a shape similar to that of Embodiment 1, but the present technology is not limited thereto. For example, as in Figure 44C Variation 3 shown, the protruding portion 551b can be arranged on the first wall portion C of the exhaust heat pipe 2151 having a shape similar to that of Figures 8A to 8D Comparative Example 1 shown, which is close to the fixing device 20. Even in this case, an effect similar to that of Embodiment 6 can be exhibited. Further, the protruding portion 551b can be arranged on the first wall portion C of the exhaust heat pipe 2251 according to Comparative Example 2 shown in Figures 9A to 9D from the upstream side in the conveyance direction CD.

[0370] Further, asFigure 44D As shown in Modification Example 4, the protruding portion 551b can be arranged on the second wall portion D of the exhaust heat pipe 2151 having a shape similar to that of Comparative Example 1 shown in Figures 8A to 8D the second wall portion D of the exhaust heat pipe 2151 shown in the figure, close to the cleaning unit 6. Even in this case, an effect similar to that of Embodiment 6 can be achieved. In addition, the protruding portion 551b can be arranged on the second wall portion D of the exhaust heat pipe 2251 according to Comparative Example 2 shown in Figures 9A to 9D the figure.

[0371] According to any of the above embodiments and comparative examples, the fixing device 20 is equipped with a heating roller 30 including a heat source, but the present technology is not limited thereto. For example, various heaters such as a ceramic heater or a halogen heater can be used as the heat source of the heating roller 30. Alternatively, instead of the heating roller 30, a fixing film formed in a film shape can be used. The fixing film is heated by various heaters such as a ceramic heater or a halogen heater. Alternatively, instead of the heating roller 30, a fixing belt having a heat generating layer can be used, wherein the heat generating layer is heated by electromagnetic induction heating.

[0372] All of the above embodiments, modification examples, and comparative examples can also be arbitrarily combined.

[0373] Although the present invention has been described with reference to exemplary embodiments, it should be understood that the present invention is not limited to the disclosed exemplary embodiments. The scope of the following claims should be construed in the broadest sense so as to cover all modifications and equivalent structures and functions.

Claims

1. An image forming apparatus configured to form a toner image on a sheet, the image forming apparatus comprising: an image bearing member configured to rotate; a developing member configured to form a toner image on the image bearing member by supplying toner to the image bearing member; a transfer member configured to transfer the toner image formed on the image bearing member to a sheet; a cleaning member configured to abut against and remove toner from a surface of the image bearing member; a toner collecting container configured to collect the toner removed from the surface of the image bearing member by the cleaning member; a fixing unit configured to fix the toner image transferred onto the sheet by the transfer member to the sheet; as well as a duct disposed between the toner collection container and the fixing unit, the duct forming an air passage through which air flowing to the outside of the image forming apparatus flows, wherein the duct includes a first wall portion opposite to the fixing unit and a second wall portion opposite to the toner collecting container, and Wherein, the first wall portion is inclined relative to the second wall portion.

2. The imaging device according to claim 1, wherein The first wall portion is inclined relative to the second wall portion so that a distance between the second wall portion and a first end portion of the first wall portion closest to a conveying path through which a sheet passes between the transfer member and the fixing unit is shorter than a distance between the second wall portion and a second end portion of the first wall portion farthest from the conveying path.

3. The imaging device according to claim 1, wherein: The first wall portion is formed linearly when viewed in the rotational axis direction of the image bearing member.

4. The imaging device according to claim 1, wherein The first wall portion is formed to be curved when viewed in the rotation axis direction of the image bearing member.

5. The imaging device according to any one of claims 1 to 4, wherein: The second wall portion extends in a vertical direction.

6. The imaging device according to any one of claims 1 to 4, wherein: The fixing unit includes a fixing member configured to heat the toner image on the sheet and a fixing cover configured to cover the fixing member, and The fixing cover includes an opposing surface that is opposite to the first wall portion and extends along the first wall portion.

7. An image forming apparatus according to any one of claims 1 to 4, further comprising a fan arranged on one side of the duct in a rotation axis direction of the image bearing member and configured to blow air, in, The duct is arranged to overlap with the fan when viewed in the rotation axis direction.

8. The imaging device according to any one of claims 1 to 4, wherein: When viewed in the rotation axis direction of the image bearing member, the second wall portion of the duct extends to a position closer to a conveyance path through which a sheet passes between the transfer member and the fixing unit than the cleaning member.

9. The imaging device according to any one of claims 1 to 4, wherein: The duct is arranged on the same side as the toner collection container with respect to a conveying path through which a sheet passes between the transfer member and the fixing unit.

Images