JP2009098189A - Fixing device and electrophotographic image forming apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing device capable of effectively removing concentrated nasty smell generated when a glossy paper is fix-processed, without making air exhausting capacity high in particular. <P>SOLUTION: Ozone smell, etc. are generated when a regular paper is fix-processed. However, the concentrated nasty smell is not generated so that air in an apparatus 1 is exhausted through the low-density filter of one exhaust port, to remove the ozone smell, etc. When the air is exhausted through the low-density filter, an air flow is excellent and the temperature rise in the apparatus 1 is sufficiently suppressed. Further, when the glossy paper is fix-processed, the concentrated nasty smell is generated so that the air in the apparatus 1 is exhausted through the high-density filter of the other exhaust port, to remove the concentrated nasty smell. When the air is exhausted through the high-density filter, the air flow is deteriorated and the temperature in the apparatus 1 tends to rise. However, it is necessary that the surface temperature of a heating roller 41 is made high for excellently fix-processing the glossy paper. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fixing device and an electrophotographic image forming apparatus using the same.

  In an electrophotographic image forming apparatus such as a copying machine, a printer, or a facsimile machine, an electrostatic latent image is formed on the surface of the photosensitive drum, and the electrostatic latent image on the surface of the photosensitive drum is developed with toner, so that the photosensitive member is developed. A toner image is formed on the drum surface, the toner image is transferred from the photosensitive drum to the recording paper, and the recording paper is heated and pressurized to fix the toner image on the recording paper.

  The fixing of the toner image on the recording paper is performed by a fixing device. In the fixing device, while the recording paper is sandwiched and conveyed in the nip area between the pair of fixing rollers, the recording paper is heated and pressurized by each fixing roller, and the toner on the recording paper is heated and melted to be fixed.

  Also, when recording on multiple types of recording paper, for example, plain paper or glossy paper, the fixing process is changed according to plain paper or glossy paper, and fixing is performed regardless of the type of recording paper. I am doing so.

For example, in Patent Document 1, when glossy paper is used, the rotation speed of an exhaust fan that raises the heating temperature of the recording paper by the fixing device, lowers the conveyance speed of the recording paper, and exhausts air in the apparatus. Is reduced.
JP 2004-109168 A

  However, when a fixing process is performed on glossy paper, a high-concentration odor is generated, but conventionally, a function for effectively removing such a high-concentration odor has not been provided. In Patent Document 1, when glossy paper is used, the rotational speed of an exhaust fan that exhausts air inside the apparatus is controlled, but odors are exhausted out of the apparatus as they are.

  In addition, in an electrophotographic image forming apparatus, an ozone odor or the like is likely to be generated, and a filter for removing such an odor may be provided. It did not lead to removal of off-flavors.

  If the density of the filter is increased to increase the odor removal capability, it is possible to remove a high concentration of off-flavors, but in this case, the flow of air exhausted through the filter becomes worse. The temperature in the apparatus rises, and the temperature in the apparatus becomes too high particularly when recording plain paper. For this reason, it is possible to increase the rotational speed of the exhaust fan or increase the size of the exhaust fan to suppress the temperature rise in the apparatus, but the power consumption increases. In recent years, image forming apparatuses have become increasingly multifunctional, and their power consumption has increased to near the allowable value of commercial power supplies, and further increase in power consumption is not preferable.

  Therefore, the present invention has been made in view of the above-described conventional problems, and eliminates high-concentration off-flavors that occur when fixing processing is performed on glossy paper without significantly increasing the air exhaust capability. It is an object of the present invention to provide a fixing device that can be effectively removed and an electrophotographic image forming apparatus using the same.

  In order to solve the above-described problems, a fixing device according to the present invention is a fixing device that pressurizes and heats a recording sheet on which a toner image is transferred to fix the toner image on the recording sheet. Exhaust means for exhausting air, wherein the exhaust means includes a plurality of exhaust ports for exhausting air, an odor removal filter provided in at least one of the exhaust ports, and each type of recording paper It has exhaust port switching means for selecting one of the exhaust ports and exhausting air through the selected exhaust port.

  For example, the exhaust port switching means selects one of the two exhaust ports according to whether the recording paper is plain paper or glossy paper, and exhausts air through the selected exhaust port. And the odor removal filter for removing a high concentration odor is provided in the exhaust port selected in the case of the said glossy paper.

  The exhaust means includes a common exhaust fan at each exhaust port.

  For example, the exhaust port switching means has a shutter that opens and closes the exhaust port, and closes the other exhaust ports except the exhaust port selected for exhausting air with the shutter.

  Each of the exhaust ports is provided on the downstream side in the recording paper conveyance direction from the fixing position of the toner image. Alternatively, each of the exhaust ports is provided on the downstream side in the recording paper conveyance direction from the fixing position of the toner image and at the fixing position of the toner image.

  On the other hand, the electrophotographic image forming apparatus of the present invention uses the fixing apparatus of the present invention.

  According to the fixing device of the present invention having such a configuration, the exhaust port switching unit selects one of the exhaust ports according to the type of the recording paper, and exhausts air through the selected exhaust port. For this reason, if each exhaust port has priority on exhaust efficiency and priority on odor removal capability, simply changing the exhaust port can improve exhaust efficiency or remove high-concentration odors. can do.

  For example, one of the two exhaust ports is selected and used depending on whether the recording paper is plain paper or glossy paper. In addition, an odor removal filter for removing high-concentration odor is provided at the exhaust port selected for glossy paper. In this case, when glossy paper is used, air is exhausted through the odor removal filter. At this time, the exhaust efficiency decreases and the temperature in the apparatus rises. However, in order to fix glossy paper satisfactorily, it is necessary to increase the fixing temperature (the temperature of the heating roller of the fixing apparatus). Even if the internal temperature rises, there is no particular problem. Therefore, it is not necessary to increase the exhaust efficiency, and the power consumption does not increase. In the case of plain paper, other exhaust ports can be used to improve the exhaust efficiency and suppress the temperature rise in the apparatus.

  Further, since any one of the exhaust ports is selectively used, a common exhaust fan can be provided at each exhaust port. This also can suppress an increase in power consumption.

  For example, the exhaust port switching means closes the other exhaust ports except for the exhaust port selected for exhausting air with a shutter. Thereby, each exhaust port can be selectively used with a simple configuration.

  Each exhaust port is provided on the downstream side in the recording paper transport direction from the fixing position of the toner image, or is provided on the downstream side in the recording paper transport direction from the fixing position of the toner image and in the fixing position of the toner image. As a result, air around the fixing portion flows and is easily exhausted.

  On the other hand, the electrophotographic image forming apparatus according to the present invention uses the fixing device according to the present invention, and therefore can achieve the same effects.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view showing an image forming apparatus to which an embodiment of a fixing device of the present invention is applied. FIG. 2 is a perspective view showing the image forming apparatus. In this image forming apparatus 1, a copy mode for reading an original image and printing it on a recording paper, a facsimile mode for reading and sending an original image, receiving an original image and printing it on a recording paper, and an information terminal device It is possible to selectively perform a printer mode or the like for printing an image received through a network on a recording sheet. The image forming apparatus 1 is roughly composed of a document conveying section 2, a document reading section 3, a printing section 4, a recording sheet conveying section 5, a sheet feeding section 6, and a sheet discharge tray 7.

  Next, taking the copy mode as an example, the operation of the image forming apparatus 1 will be described.

  When at least one document is set on the document set tray 11 in the document transport unit 2, the document is pulled out from the document set tray 11 one by one and transported, and the leading edge of the document is temporarily stopped. 12 so that the leading edge of the document is parallel to the PS roller 12. Then, after synchronizing with the image recording operation by the printing unit 4, the clutch between the PS roller 12 and the drive shaft is turned on, the PS roller 12 is rotationally driven, and the original is re-conveyed by the PS roller 12. Is passed between the platen glass 8 a and the document pressing plate 9.

  In the document reading unit 3, when the document is transported, the document is exposed by the first scanning unit 15, and the reflected light from the document is guided to the imaging lens 17 by the first and second scanning units 15, 16, thereby forming the imaging lens. The original image is formed on a photoelectric conversion element (hereinafter referred to as CCD) 18 by 17. The CCD 18 repeatedly scans and reads the document in the main scanning direction, and outputs image data indicating the document.

  When the document is placed on the platen glass 8b, the first and second scanning units 15 and 16 are moved while maintaining a predetermined speed relationship with each other, and the first scanning unit 15 moves the platen glass 8b onto the platen glass 8b. The original is exposed, reflected light from the original is guided to the imaging lens 17 by the first and second scanning units 15 and 16, and the original is imaged on the CCD 18 by the imaging lens 17.

  The image data output from the CCD 18 is subjected to various image processing by a control circuit such as a microcomputer and then output to the printing unit 4.

  The printing unit 4 records a document indicated by image data on a recording sheet, and includes a photosensitive drum 21, a roller charging device 22, a laser scanning unit (hereinafter referred to as LSU) 23, a developing device 24, and a transfer device 25. , A cleaning device 26, a static elimination device (not shown), a fixing device 27, and the like. The photosensitive drum 21 rotates in one direction, and after the surface thereof is cleaned by the cleaning device 26 and the charge eliminating device, the surface is uniformly charged by the roller charging device 22. The laser scanning unit 23 modulates the laser light according to the image data, and repeatedly scans the surface of the photosensitive drum 21 in the main scanning direction with the laser light to form an electrostatic latent image on the surface of the photosensitive drum 21. The developing device 24 supplies toner to the surface of the photosensitive drum 21 to develop the electrostatic latent image, and forms a toner image on the surface of the photosensitive drum 21. The transfer device 25 transfers the toner image on the surface of the photosensitive drum 21 onto the recording paper conveyed by the recording paper conveyance unit 5. The fixing device 27 heats and pressurizes the recording paper to fix the toner image on the recording paper. Thereafter, the recording sheet is further conveyed to the sheet discharge tray 7 by the recording sheet conveying unit 5 and discharged.

  The recording paper transport unit 5 includes a PS roller 28, a transport roller 29, a transport path 31, a reverse transport path 32, a paper discharge roller 33, a branch claw 34, and the like for transporting the recording paper. In the conveyance path 31, the recording paper is received from the paper feeding unit 6 and conveyed to the PS roller 28, and the leading edge of the recording paper is brought into contact with the PS roller 28 that is temporarily stopped so that the leading edge of the recording paper is PS. Parallel to the roller 28, the recording paper is then conveyed by the PS roller 28 to the transfer device 25 of the printing unit 4, and the recording paper is further conveyed to the paper discharge tray 7. Further, when an image is also recorded on the back side of the recording paper, the branching claw 34 is rotated to switch the branch path between the transport path 31 and the reverse transport path 32, and then the recording paper is transferred from the transport path 31 to the reverse transport path 32. Transport in the opposite direction. In the reverse conveyance path 32, when the recording sheet is received from the conveyance path 31, the recording sheet is reversed to the reverse side and then returned to the PS roller 28 in the conveyance path 31. As a result, the recording paper is conveyed to the transfer device 25, and an image is also recorded on the back surface of the recording paper. A plurality of detection switches for detecting the passage of the recording paper are arranged in the transport paths 31 and 32, and control of the recording paper transport timing and the like is performed based on the detection of each detection switch.

  The paper feed unit 6 accommodates unused recording paper and supplies the unused recording paper to the recording paper transport unit 5, and includes a paper feed cassette 36. Recording paper is stacked and stored in the paper feed cassette 36, and the recording paper is pulled out one by one by a semi-cylindrical pickup roller 35 and conveyed to the PS roller 28.

  By the way, in the fixing device 27 of the present embodiment, as shown in FIG. 3, a heating roller (also referred to as a fixing roller) 41 and a pressure roller (also referred to as a fixing roller) 42 are axially supported in a state where they are pressed against each other, A nip area N in which the recording paper is sandwiched between the heating roller 41 and the pressure roller 42 is formed, and the recording paper is heated and pressed through the nip area N to fix the toner image on the recording paper.

  A temperature sensor 43 is provided on the outer periphery of the heating roller 41, the surface temperature of the heating roller 41 is detected by the temperature sensor 43, and the surface temperature of the heating roller 41 is output to the control unit 44. When the surface temperature of the heating roller 41 is input, the control unit 44 controls the heat generation of the heater 45 inside the heating roller 41 so that the surface temperature of the heating roller 41 becomes a predetermined temperature.

  Further, the heating roller 41 is driven to rotate by a roller driving mechanism 46, and the pressure roller 42 is driven to rotate. The control unit 44 can drive and control the roller driving mechanism 46 to adjust and control the rotation speeds of the rollers 41 and 42.

  Here, in the image forming apparatus 1, the fixing process by the fixing device 27 is changed according to the type of recording paper so that a toner image can be favorably formed regardless of the type of recording paper.

  For example, the fixing process is changed according to plain paper or glossy paper. If the recording paper is plain paper, the control unit 44 adjusts and controls the surface temperature of the heating roller 41 of the fixing device 27 to a normal specified temperature, and sets the rotation speeds of the rollers 41 and 42 to normal normal speeds. To do. Further, if the recording paper is glossy paper, the control unit 44 adjusts and controls the surface temperature of the heating roller 41 to a constant temperature higher than the normal specified temperature, and the rotational speed of the rollers 41 and 42 to the normal specified temperature. By adjusting and controlling at a constant speed lower than the speed, the recording paper, which is glossy paper, is heated more sufficiently than the plain paper, and the toner image on the glossy paper is fixed well. Examples of glossy paper include OHT sheet and gloss paper.

  Also, in the vicinity of the fixing device 27, the ambient temperature rises due to heat generated by the heating roller 41 and other electrical parts of the fixing device 27. If this temperature rise is left as it is, the ambient temperature becomes too high. As a result, problems such as an excessive increase in the fixing temperature in the nip region N of the rollers 41 and 42 of the fixing device 27 occur. For this reason, an exhaust device 51 is provided that discharges the air in the image forming apparatus 1 to the outside and introduces new air into the apparatus 1 to suppress an increase in the ambient temperature.

  The exhaust device 51 is provided on the right side wall of the device 1 and in the vicinity of the fixing device 27. The exhaust device 51 sucks air on the downstream side of the fixing device 27 in the paper transport direction and discharges it to the outside. In the image forming apparatus 1, an air flow in the paper conveyance direction is generated, and the air heated by the fixing device 27 flows downstream, so that the air downstream from the fixing device 27 is sucked. If it is discharged to the outside, the heated air can be efficiently discharged to the outside.

  Further, since a high voltage is used at the time of charging or transferring, an ozone odor or the like is generated, or a high-concentration odor is generated at the time of fixing processing of glossy paper by the fixing device 27. Therefore, a filter for removing the odor Is provided in the exhaust device 51, and the air in the device 1 is passed through the filter of the exhaust device 51 to remove the odor component of the air by the filter, and then the air is discharged to the outside.

  However, a high-density filter is required to remove the high-concentration odor during the glossy paper fixing process. However, if the air is exhausted through the high-density filter, the air flow deteriorates and the apparatus 1 It becomes difficult to adjust and control the temperature of the heating roller 41 appropriately.

  Therefore, in this image forming apparatus 1, the exhaust device 51 is configured to be able to selectively use two exhaust ports, a low-density filter is provided at one exhaust port, giving priority to exhaust efficiency, and the other A high-density filter is provided at the exhaust port to remove high-concentration off-flavors.

  During the fixing process of plain paper, an ozone odor or the like is generated, but a high-concentration odor is not generated. Therefore, the air in the apparatus 1 is exhausted through a low-density filter at one exhaust port, and the low-density filter To remove ozone odor. When the air is exhausted through the low density filter, the air flow is good, the temperature rise in the apparatus 1 is sufficiently suppressed, and the temperature adjustment control of the heating roller 41 is easy.

  Further, during the glossy paper fixing process, a high-concentration odor is generated, so the air in the apparatus 1 is exhausted through the high-density filter at the other exhaust port, and the high-density odor is removed by the high-density filter. When air is exhausted through this high-density filter, the air flow tends to deteriorate and the temperature in the apparatus 1 tends to rise. However, as described above, in order to satisfactorily fix glossy paper, heating is required. Since the surface temperature of the roller 41 is adjusted and controlled to a constant temperature higher than the normal specified temperature, even if the temperature in the apparatus 1 rises, the surface temperature of the heating roller 41 is not increased unless the temperature in the apparatus 1 becomes abnormally high. Adjustment control is possible.

  FIG. 4A is a cross-sectional view schematically showing the configuration of the exhaust device 51. As shown in FIG. 4 (a), the exhaust device 51 includes an exhaust fan 52 and two exhaust ports 53, 54, a high-density filter 55 is provided in the upper exhaust port 53, and a lower exhaust gas is provided. A shutter 56 and a low-density filter 57 are stacked on the mouth 54 in parallel.

  As shown in FIG. 4B, the shutter 56 is formed by superposing two shutter plates 58 and 59 so as to be slidable with respect to each other. In a state where the shutter plates 58 and 59 are completely overlapped, the openings 58a of one shutter plate 58 and the openings 59a of the other shutter plate 59 overlap each other, and pass through the openings 58a and the openings 59a. Air can be circulated, the shutter 56 is opened, and the lower exhaust port 54 is opened. At this time, the air exhausted by the exhaust fan 52 is exhausted to the outside through the low density filter 57 of the lower exhaust port 54. Further, since the upper exhaust port 53 is always open, air is also discharged to the outside through the high-density filter 55, but the air resistance of the high-density filter 55 is larger than the air resistance of the low-density filter 57, and the exhaust gas is exhausted. Most of the air exhausted by the fan 52 is exhausted through the low density filter 57, and only a small amount of the remaining air is exhausted through the high density filter 55. That is, when the shutter 56 is opened, the lower exhaust port 54 is opened, and most of the air exhausted by the exhaust fan 52 is exhausted through the low density filter 57.

  Further, as shown in FIGS. 5A and 5B, in a state where the shutter plates 58 and 59 of the shutter 56 are slid and shifted from each other, the openings 58a of one shutter plate 58 and the other shutter plate 58. Each opening 59a of 59 is also displaced, the shutter 56 is closed, and the lower exhaust port 54 is closed. At this time, the air exhausted by the exhaust fan 52 does not pass through the lower exhaust port 54, but since the upper exhaust port 53 is always open, the air is discharged to the outside through the high-density filter 55. The Although the air resistance of the high density filter 55 is large, the air exhausted by the exhaust fan 52 passes through only the high density filter 55 and is discharged to the outside.

  The opening / closing drive of the shutter 56 is performed by the control unit 44 depending on whether the recording paper is plain paper or glossy paper. In the image forming apparatus 1, when the recording sheet is recorded, the type of the recording sheet is instructed by operating the operation panel 14 (shown in FIG. 1). For example, plain paper is determined as a default, and glossy paper can be input by operating the operation panel.

  The control unit 44 drives and controls the shutter drive mechanism 47 during recording of plain paper, opens the shutter 56, opens the lower exhaust port 54, and the air exhausted by the exhaust fan 52 is on the lower side. The air is discharged through a low-density filter 57 at the exhaust port 54. For this reason, even if ozone odor etc. generate | occur | produce, ozone odor etc. are removed by the low density filter 57, the temperature rise in the apparatus 1 is fully suppressed, and the adjustment control of the temperature of the heating roller 41 becomes easy.

  Further, the control unit 44 drives and controls the shutter drive mechanism 47 when recording glossy paper, closes the shutter 56, closes the lower exhaust port 54, and the air exhausted by the exhaust fan 52 is exhausted. It is made to discharge through the high density filter 55 of the upper exhaust port 53. For this reason, even if a high-concentration odor occurs, the high-density filter 55 removes the high-concentration odor. At this time, the temperature in the apparatus 1 does not become abnormally high, and it becomes easy to adjust and control the surface temperature of the heating roller 41 to a high temperature suitable for fixing glossy paper.

  6A and 6B show a modification of the shutter 56. FIG. The shutter 61 of this modification is formed by superimposing two shutter plates 62 and 63 so as to be slidable with each other, and is disposed at the upper and lower exhaust ports 53 and 54. Each shutter plate 62, 63 has an opening 62a, 63a located at the upper exhaust port 53 and an opening 62b, 63b located at the lower exhaust port 54, respectively. In a state where the shutter plates 62 and 63 are completely overlapped, the openings 62a and 63a located at the upper exhaust port 53 are displaced, and the openings 62b and 63b located at the lower exhaust port 54 are overlapped. Only the lower exhaust port 54 is opened. At this time, the air exhausted by the exhaust fan 52 is exhausted to the outside through the low density filter 57 of the lower exhaust port 54.

  Also, as shown in FIGS. 7A and 7B, in a state where the shutter plates 62 and 63 of the shutter 61 are slid and shifted from each other, the openings 62b and 63b positioned in the lower exhaust port 54, respectively. Accordingly, the openings 62a and 63a located at the upper exhaust port 53 are overlapped, and only the upper exhaust port 53 is opened. At this time, the air exhausted by the exhaust fan 52 is exhausted to the outside through the high density filter 55 of the upper exhaust port 53.

  FIGS. 8A and 8B show another modification of the shutter 56. The shutter 64 of this modification has a flat plate shape, the lower side of which is pivotally supported, and is reciprocally rotated around the pivotal axis of the lower side. As shown in FIG. 8A, when the shutter 64 is tilted substantially horizontally, the lower exhaust port 54 is opened. At this time, the air exhausted by the exhaust fan 52 is exhausted to the outside through the low density filter 57 of the lower exhaust port 54. Although the upper exhaust port 53 is always open, the air resistance of the high density filter 55 is larger than the air resistance of the low density filter 57, and most of the air exhausted by the exhaust fan 52 is low density filter 57. It is discharged through. That is, when the shutter 64 is tilted, the lower exhaust port 54 is opened, and most of the air exhausted by the exhaust fan 52 is exhausted through the low density filter 57.

  Further, as shown in FIG. 8B, in a state where the shutter 64 is driven to rotate about the pivot shaft on the lower side and is raised substantially vertically, the lower exhaust port 54 is closed. At this time, the air exhausted by the exhaust fan 52 does not pass through the lower exhaust port 54, but since the upper exhaust port 53 is always open, the air is discharged to the outside through the high-density filter 55. The

  9 and 10 show modifications of the exhaust device. The exhaust device 81 of this modified example includes an exhaust fan 82 and two exhaust ports 83, 84. The upper exhaust port 83 is directed upward, and the high-density filter 85 is connected to the upper exhaust port 83. In addition, the lower exhaust port 84 is directed in the horizontal direction, and the shutter 86 and the low-density filter 87 are arranged side by side on the lower exhaust port 84.

  The shutter 86 has the same configuration as the shutter 56 in FIG. 4B, and the shutter 86 is opened when the two shutter plates are slidably overlapped with each other and the shutter plates are completely overlapped. In addition, the shutter 86 is closed in a state where the shutter plates are slid and shifted from each other.

  In a state where the shutter 86 is opened, the air exhausted by the exhaust fan 82 is discharged from the exhaust port 84 on the right side wall of the image forming apparatus 1 to the side through the low density filter 87 of the lower exhaust port 84. The At this time, the upper exhaust port 83 is also opened, but since a high-density filter 85 is provided, only a small amount of air is discharged through the high-density filter 85.

  When the shutter 86 is closed, the air exhausted by the exhaust fan 82 is discharged upward from the exhaust port 83 on the upper surface of the image forming apparatus 1 through the high-density filter 85 of the upper exhaust port 83.

  Therefore, during the fixing process of plain paper, air containing components such as ozone odor passes through the low density filter 87 and is discharged to the side of the image forming apparatus 1, and during the fixing process of glossy paper, Air containing a high-concentration off-flavor component passes through the high-density filter 85 and is discharged to the upper side of the image forming apparatus 1.

  In the image forming apparatus 1, since the paper discharge tray 7 is provided below the document conveying unit 2 and the document reading unit 3, the user should discharge the air that has passed through the high-density filter 85 upward. When taking out the recording paper from the paper tray 7, it is difficult to detect the odor leaking from the high density filter 85.

  Depending on the configuration of the image forming apparatus, the air that has passed through the low-density filter 87 may be discharged above the apparatus, and the air that has passed through the high-density filter 85 may be discharged to the side of the apparatus.

  Further, the present invention is not limited to the above embodiment, and can be variously modified. For example, if no ozone odor or the like is generated during the fixing process of plain paper, the low density filter can be omitted.

1 is a cross-sectional view illustrating an image forming apparatus to which an embodiment of a fixing device of the present invention is applied. FIG. 2 is a perspective view showing the image forming apparatus of FIG. 1. FIG. 2 is a diagram schematically showing a fixing device in the image forming apparatus of FIG. 1. (A) is a sectional view showing an exhaust device provided in the vicinity of the fixing device, and (b) is a perspective view showing a shutter of the exhaust device. (A) is sectional drawing which shows the exhaust apparatus when a shutter is closed, (b) is a perspective view which shows the state which closed the shutter of the exhaust apparatus. (A) is sectional drawing which shows the exhaust apparatus which applied the other shutter, (b) is a perspective view which shows another shutter. (A) is sectional drawing which shows the exhaust apparatus when another shutter is closed, (b) is a perspective view which shows the state which closed the other shutter. (A) is sectional drawing which shows the exhaust apparatus which applied another shutter, (b) is sectional drawing which shows an exhaust apparatus when another shutter is closed. It is sectional drawing which shows the modification of an exhaust apparatus. It is a perspective view which shows the image forming apparatus to which the exhaust apparatus of FIG. 9 is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Document conveying part 3 Scanner part 4 Printing part 6 Paper feed part 7 Paper discharge tray 21 Photosensitive drum 22 Roller charging device 23 Laser scanning unit 24 Developing device 25 Transfer device 26 Cleaning device 41 Heating roller 42 Pressure roller 43 Temperature Sensor 44 Control Unit 51 Exhaust Device 52 Exhaust Fan 53, 54 Exhaust Port 55 High Density Filter 56 Shutter 57 Low Density Filter 58, 59 Shutter Plate

Claims (8)

In a fixing device that pressurizes and heats a recording sheet on which a toner image is transferred, and fixes the toner image on the recording sheet.
An exhaust means for exhausting air around the fixing device;
The exhaust means selects a plurality of exhaust ports for exhausting air, an odor removal filter provided in at least one of the exhaust ports, and each exhaust port according to the type of recording paper, A fixing device comprising exhaust port switching means for exhausting air through the selected exhaust port.   The exhaust port switching means selects one of two exhaust ports according to whether the recording paper is plain paper or glossy paper, and exhausts air through the selected exhaust port. Item 4. The fixing device according to Item 1.   The fixing device according to claim 2, wherein an odor removing filter for removing a high-concentration odor is provided at an exhaust port selected when the glossy paper is used.   The fixing device according to claim 1, wherein the exhaust unit includes an exhaust fan common to the exhaust ports.   The exhaust port switching means has a shutter for opening and closing the exhaust port, and other exhaust ports except for the exhaust port selected for exhausting air are closed by the shutter. Fixing device.   The fixing device according to claim 1, wherein each of the exhaust ports is provided on a downstream side in a recording sheet conveyance direction from a fixing portion of the toner image.   2. The fixing device according to claim 1, wherein each of the exhaust ports is provided on a downstream side of the toner image fixing position in a recording sheet conveyance direction and at a fixing position of the toner image.   An electrophotographic image forming apparatus using the fixing device according to claim 1.

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