JP5899293B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic image forming apparatus, and in particular, an image including a fixing device that fixes a toner image on a sheet and a sheet discharge roller unit that discharges the sheet on which the toner image is fixed to a sheet discharge tray. The present invention relates to a forming apparatus.

  2. Description of the Related Art Conventionally, an electrophotographic image forming apparatus such as a printer, a copier, a facsimile machine, a multifunction machine, etc. includes a fixing device that heats and pressurizes a toner image and fixes the toner image on a paper, and a paper on which the toner image is fixed by the fixing device And a paper discharge roller unit for discharging the paper to the paper discharge tray.

  In such an image forming apparatus, when the toner image is fixed on the sheet by the fixing device, the sheet is heated, and when the heated sheet is heated and stacked on the discharge tray, the toner on one sheet is transferred to the other sheet. This causes a problem that the toner is peeled off after being attached to the paper. Further, when the container for storing the toner is disposed below the paper discharge tray, heat from the high-temperature paper stacked on the paper discharge tray is transmitted to the container through the paper discharge tray, and the toner in the container There arises a problem that the material becomes solid at a high temperature.

  In order to solve this problem, for example, as disclosed in Patent Document 1, a fan dedicated to sheet cooling is often installed. The reason why such a configuration is often used is that when a fan that cools another heat source (for example, a fixing device) in the image forming apparatus is used together with the sheet cooling fan, the other heat source is cooled to increase the temperature. This is because the paper is cooled by the weakened cooling air, and the paper cooling effect cannot be sufficiently obtained.

JP 2002-72729 A

  However, in the image forming apparatus described in Patent Document 1, cooling air from the fan is blown toward the downstream side of the paper discharge roller unit (see FIG. 1 in Patent Document 1). For this reason, the sheet passing through the sheet discharge roller unit cannot be reliably cooled, and it has been difficult to sufficiently solve the problem that the toner is peeled off from the sheet.

  In addition, if a fan dedicated to cooling the paper is installed as in Patent Document 1, the number of fans installed in the image forming apparatus increases, and new problems such as an increase in cost, a space problem, and a noise problem occur. End up.

  In view of the above-described circumstances, an object of the present invention is to sufficiently prevent the toner from being peeled off from the paper by sufficiently cooling the paper before being discharged to the paper discharge tray.

  An image forming apparatus according to the present invention includes a conveyance path for conveying a sheet, a fixing device for fixing a toner image on the sheet conveyed along the conveyance path, and a sheet on which the toner image is fixed by the fixing device. An image forming apparatus including a discharge roller unit for finally discharging to a discharge tray, wherein the discharge tray is provided with a blowing port for sending cooling air toward the discharge roller unit The image forming apparatus is disposed on the lower surface side of the paper discharge tray and contains a container, a container cooling fan that is disposed on the lower surface side of the paper discharge tray and cools the container, The fixing device including a heating roller disposed along a conveyance path, a heating unit provided in the fixing device, a cooling fan for a heating unit that cools the heating unit, and the container A first duct extending from the rejection fan to the air blowing port without passing through the fixing device, and a second duct extending from the container cooling fan to the cooling fan for the heating unit, and one longitudinal end portion of the heating unit Is provided with a cooling intake port to which the cooling fan for the heating means is connected, and a cooling exhaust port for discharging the cooling air flowing in from the cooling intake port is provided at the other longitudinal end of the heating means. The cooling intake port and the cooling exhaust port are provided on the same side as the heating roller with respect to the transport path.

  By adopting such a configuration, it becomes possible to reliably blow cooling air on the paper passing through the paper discharge roller unit, and it is possible to sufficiently cool the paper before it is discharged to the paper discharge tray. Become. Therefore, it is possible to suppress a problem in which high-temperature paper is stacked on the paper discharge tray and the toner of one paper sticks to another paper and the toner is peeled off. In addition, the existing paper discharge tray is equipped with an air outlet, so there is no need to add a separate member to form the air outlet, so the number of parts can be reduced and costs can be reduced. It becomes.

  The fixing device may further include an intake duct connecting the cooling fan for the heating unit and the cooling intake port.

  The fixing device may further include an exhaust duct connecting the cooling exhaust port and a space on the back side of the device.

  According to the image forming apparatus of the present invention, by sufficiently cooling the paper before being discharged to the paper discharge tray, it is possible to suppress a problem that the toner is peeled off from the paper.

1 is a schematic diagram illustrating an outline of a configuration of a color printer according to a first embodiment of the present invention. 1 is a cross-sectional view showing an upper part of a color printer according to a first embodiment of the present invention. FIG. 3 is an enlarged view of a main part of FIG. 2. In the color printer according to the first embodiment of the present invention, it is a perspective view from below showing a first paper discharge tray. In the color printer according to the first embodiment of the present invention, it is a perspective view from above showing a first paper discharge tray. It is sectional drawing which shows the upper part of the color printer which concerns on the 2nd Embodiment of this invention. It is a perspective view which shows an IH coil unit in the color printer which concerns on the 2nd Embodiment of this invention.

<First Embodiment>
First, an outline of a configuration of a color printer 1 as an image forming apparatus according to the first embodiment will be described with reference to FIG. FIG. 1 is a schematic diagram illustrating an outline of a configuration of a color printer according to a first embodiment of the present invention.

  The color printer 1 includes a box-shaped printer main body 2. A paper feed cassette 3 that stores paper (not shown) is provided at the lower portion of the printer main body 2. The paper discharge tray 4 is provided. A second paper discharge tray 5 is provided above the first paper discharge tray 4.

  An intermediate transfer belt 6 as an image carrier is installed between a plurality of rollers inside the printer body 2, and below the intermediate transfer belt 6, an exposure unit 7 composed of a laser scanning unit (LSU). Are arranged, and four image forming portions 8 are provided for each toner color (for example, four colors of magenta, cyan, yellow, and black) along the lower portion of the intermediate transfer belt 6.

  Each image forming unit 8 is rotatably provided with a photosensitive drum 9, and around the photosensitive drum 9, a charger 10, a developing unit 11, a primary transfer unit 12, and a cleaning device 13 are provided. The static eliminator 14 is arranged in the order of the primary transfer process.

  A pair of stirring rollers 15 is provided below the developing device 11, a magnetic roller 16 is provided obliquely above the stirring roller 15, and a developing roller 17 is provided obliquely above the magnetic roller 16. Four containers 18 are provided above the developing unit 11. Each container 18 contains toner of a color corresponding to each image forming unit 8.

  A conveyance path 20 is provided on one side (right side in the drawing) of the printer main body 2. A paper feed unit 21 is provided at the upstream end of the conveyance path 20, and a secondary transfer unit 22 is provided at one end (right end in the drawing) of the intermediate transfer belt 6 at a middle portion of the conveyance path 20, downstream of the conveyance path 20. The fixing device 23 is provided in the section.

  The conveyance path 20 branches up and down at a portion downstream of the fixing device 23. A first paper discharge roller unit 25 is provided on the upper one side (upper right side in the drawing) of the first paper discharge tray 4 at the downstream end of the first conveyance path 24 which is a lower branch path. Yes. A second paper discharge roller unit 27 is provided on the upper side of the second paper discharge tray 5 (upper right side in the drawing) at the downstream end of the second conveyance path 26 that is the upper branch path. .

  The second paper discharge roller unit 27 includes a part on the upstream side of the secondary transfer portion 22 of the transport path 20 and a reverse path 28 for duplex printing provided on one side (right side in the drawing) of the transport path 20. Connected through.

  Next, an image forming operation of the color printer 1 having such a configuration will be described. When the color printer 1 is turned on, various parameters are initialized, and initial settings such as temperature setting of the fixing device 23 are executed. When image data is input from a computer or the like connected to the color printer 1 and an instruction to start printing is given, an image forming operation is executed as follows.

  First, after the surface of the photosensitive drum 9 is charged by the charger 10, the photosensitive drum 9 is exposed according to the image data by the laser light (see arrow P) from the exposure device 7, and the photosensitive member is exposed. An electrostatic latent image is formed on the surface of the drum 9. Next, the electrostatic latent image is developed into a toner image of a corresponding color by the developing device 11 with the toner supplied from the container 18. This toner image is primarily transferred to the surface of the intermediate transfer belt 6 in the primary transfer portion 12. Each image forming unit 8 sequentially repeats the above operation, whereby a full-color toner image is formed on the intermediate transfer belt 6. Note that the toner and charge remaining on the photosensitive drum 9 are removed by the cleaning device 13 and the static eliminator 14.

  On the other hand, the paper taken out from the paper feed cassette 3 or the hand tray (not shown) by the paper feed unit 21 is conveyed to the secondary transfer unit 22 in synchronism with the above-described image forming operation, and is subjected to secondary transfer. In the section 22, the full color toner image on the intermediate transfer belt 6 is secondarily transferred to the paper. The sheet on which the toner image is secondarily transferred is conveyed downstream in the conveyance path 20 and enters the fixing device 23, and the toner image is fixed on the sheet by the fixing device 23. The sheet on which the toner image is fixed enters either the first conveyance path 24 or the second conveyance path 26. The paper that has entered the first transport path 24 is finally discharged onto the first paper discharge tray 4 by the first paper discharge roller unit 25. The paper that has entered the second transport path 26 is finally discharged onto the second paper discharge tray 5 by the second paper discharge roller unit 27, or to the reverse path 28 for duplex printing. Be transported.

  Next, the container 18 and its periphery will be described in detail with reference to FIGS. FIG. 2 is a cross-sectional view showing the upper part of the color printer according to the first embodiment of the present invention. FIG. 3 is an enlarged view of a main part of FIG. FIG. 4 is a perspective view showing the first paper discharge tray from the lower side in the color printer according to the first embodiment of the present invention. FIG. 5 is a perspective view from above showing the first paper discharge tray in the color printer according to the first embodiment of the present invention. In FIGS. 2 and 3, the white arrow indicates the flow of cooling air, and the thick line S indicates the paper.

  As shown in FIG. 2, each container 18 is detachably attached to a container storage portion 31 provided at the upper part of the printer main body 2. The container storage unit 31 has four mounting parts 33 that are partitioned by a plurality of side plates 32 side by side, and each mounting part 33 is detachably mounted with the container 18 described above.

  As shown in FIG. 3, the fixing device 23 is provided on the right side of the rightmost container 18. The fixing device 23 is partitioned by a container storage portion 31 and a partition plate 34, and a step portion 35 is provided on the partition plate 34.

  The fixing device 23 includes a heating roller 36, a pressure roller 37 provided on the right side of the heating roller 36, and an IH coil unit 38 provided on the left side of the heating roller 36. That is, the fixing device 23 is an induction heating type (IH type) fixing device 23.

  The pressure roller 37 is in pressure contact with the heating roller 36 by an urging force of an urging means (not shown), and a fixing nip 40 is formed between the heating roller 36 and the pressure roller 37. Is rotated by the rotation of the heating roller 36. The sheet conveyed along the conveyance path 20 is heated and pressurized at the fixing nip 40 to fix the toner image on the sheet.

  The IH coil unit 38 is housed in the case member 41, the case member 41, and arranged in an arc along the outer periphery of the heating roller 36, and the case member 41 is housed in the induction heating coil. Arch core 43 disposed along the outer periphery of 42. The arch core 43 is made of ferrite, for example.

  A first paper discharge roller unit 25 is provided at the upper right of the rightmost container 18. The first paper discharge roller unit 25 includes a driving roller 44 and a driven roller 45 disposed above the driving roller 44.

  The driving roller 44 is connected to a driving source (not shown) via a plurality of gears (not shown), and is configured to rotate by driving force from the driving source. The driven roller 45 is in pressure contact with the driving roller 44, and a discharge nip 46 is formed between the driving roller 44 and the driven roller 45, and the driven roller 45 rotates as the driving roller 44 rotates. Yes. Then, by rotating the driving roller 44 and the driven roller 45, the paper conveyed along the conveying path 20 can be discharged to the first paper discharge tray 4.

  As shown in FIG. 2, a container cooling fan 47 is provided on the left side of the leftmost container 18. The container cooling fan 47 is installed on the opposite side of the fixing device 23 with the containers 18 interposed therebetween. The container cooling fan 47 is installed in such a direction that air can be blown from the left to the right. On the left side of the container cooling fan 47, a left cover 48 that forms a part of the exterior cover is provided in the vertical direction.

  A main duct 50 is formed in the left-right direction above each container 18, and the first discharge tray 4 is provided so as to cover the upper side of the main duct 50. The first paper discharge tray 4 includes a mounting portion 51 that extends substantially in the left-right direction, and a protrusion that protrudes from the right end portion of the mounting portion 51 toward the first paper discharge roller unit 25 (upper side in the present embodiment). 54.

  The placement unit 51 is located on the lower left side of the first paper discharge roller unit 25, and the paper discharged from the first paper discharge roller unit 25 is placed on the placement unit 51. Yes. A stopper storage portion 52 that is recessed downward is provided at the left end portion of the placement portion 51, and a paper stopper 53 is stored in the stopper storage portion 52.

  A louver 55 that is inclined to the lower left is provided at the left end of the mounting portion 51, and the lower end of the louver 55 is in contact with the upper end of the left cover 48. The louver 55 is disposed outside the container cooling fan 47 (on the left side in the present embodiment), and is provided so as to cover the upper part of the left side surface of the container cooling fan 47. The louver 55 has a plurality of air inlets 56 formed in the horizontal direction. Each intake port 56 has, for example, a horizontally long slit shape, and is provided in three rows in the vertical and horizontal directions.

  A portion extending from the left end portion to the right side portion of the mounting portion 51 bulges upward. As shown in FIG. 4, a plurality of ribs 57 project from the lower surface of the mounting portion 51 along the left-right direction at positions corresponding to the above-described bulging portions.

  As shown in FIG. 5 and the like, the protrusion 54 is bent from the right end portion of the mounting portion 51 upward and the first side plate 58 is bent rightward from the upper end of the first side plate 58. An upper plate 60 and a second side plate 61 bent downward from the right end of the upper plate 60.

  As shown in FIG. 3, a sub duct 62 is formed on the protrusion 54 between the first side plate 58 and the second side plate 61. The sub duct 62 has a width that is gradually narrowed upward. The sub duct 62 communicates with the main duct 50 through a gap 63 between the first side plate 58 and the partition plate 34. The lower end portion of the second side plate 61 is in contact with the stepped portion 35 of the partition plate 34.

  A blower port 64 is formed at the tip of the projection 54 so as to straddle the upper plate 60 and the second side plate 61, and the space on the side of the sub duct 62 and the first paper discharge roller unit 25 is formed through the blower port 64. Communicate. As described above, in the present embodiment, the main duct 50, the gap 63 between the first side plate 58 and the partition plate 34, and the sub duct 62 form the duct 66 from the container cooling fan 47 to the air outlet 64. Has been.

  As shown in FIG. 5, the air outlet 64 has a shape that is long in the front-rear direction. The projection 54 is provided with a plurality of auxiliary plates 65 between the first side plate 58 and the second side plate 61, and the auxiliary plate 65 divides the air blowing port 64 forward and backward.

  In the configuration as described above, when the container cooling fan 47 is operated along with the image forming operation, the outside air introduced through the inlet 56 of the louver 55 is sucked into the container cooling fan 47, and the arrow in FIG. As indicated by A, the cooling air from the container cooling fan 47 flows through the main duct 50 from left to right. Each container 18 is cooled by the cooling air.

  As indicated by an arrow B in FIG. 3, the cooling air that has cooled each container 18 flows into the sub duct 62 through the gap 63, and is near the discharge nip 46 of the first discharge roller unit 25 from the blower port 64. It is blown out toward. The sheet conveyed to the first paper discharge roller unit 25 is cooled by the blown cooling air.

  As described above, in the present embodiment, the first discharge tray 4 is provided with the air outlet 64 for sending the cooling air toward the first discharge roller unit 25. Therefore, it is possible to reliably blow the cooling air onto the paper passing through the first paper discharge roller unit 25 (see FIG. 3), and the paper is sufficiently cooled before being discharged to the first paper discharge tray 4. It becomes possible to do. Accordingly, it is possible to suppress a problem in which high-temperature paper is stacked on the first paper discharge tray 4 and the toner of one paper sticks to another paper and the toner is peeled off. In addition, since the air outlet 64 is provided in the first discharge tray 4 which is an existing part, and it is not necessary to add a member for forming the air outlet 64 separately, the number of parts is reduced and the cost is reduced. Can be achieved.

  Further, since the duct 66 extending from the container cooling fan 47 to the blower port 64 is formed, both the container 18 and the paper can be cooled by the cooling air from the container cooling fan 47. That is, the container cooling fan 47 can be used for cooling the paper. Therefore, it is possible to reduce the number of fans as compared with the case where a fan dedicated to cooling the paper is provided, and it is possible to reduce manufacturing costs, save space, and reduce noise. In addition, since the configuration is simple, it can be easily mounted on an actual machine.

  Although the temperature of the cooling air after cooling each container 18 is slightly increased, the temperature is sufficiently lower than that of the paper passing through the first paper discharge roller unit 25 with heat. For this reason, it is possible to sufficiently cool the sheet.

  In this embodiment, since the main duct 50 is formed between the first paper discharge tray 4 on which sheets are stacked and the container 18, heat from the sheet to the container 18 is generated by the cooling air flowing through the main duct 50. Transmission can be cut off, and the cooling performance of each container 18 can be further enhanced.

  Also, a plurality of ribs 57 project from the lower surface of the first paper discharge tray 4 covering the upper side of the main duct 50 along the air blowing direction of the container cooling fan 47. Therefore, it is possible to prevent the cooling air from diffusing into the space around each container 18 by the ribs 57, and it is possible to reliably supply a certain amount of cooling air to the air outlet 64. Therefore, it becomes possible to further enhance the cooling effect of the paper.

  Further, since the container cooling fan 47 is installed on the opposite side of the fixing device 23 with each container 18 interposed therebetween, the container cooling fan 47 can be installed at a position separated from the fixing device 23 which is the largest heat source. Become. For this reason, it is possible to suppress the cooling air from the container cooling fan 47 from being heated by heat generated from the fixing device 23, and it is possible to further improve the cooling performance of the container 18 and the paper.

  Further, a protrusion 54 that protrudes toward the first paper discharge roller unit 25 is provided on the first paper discharge tray 4, and a blower port 64 is formed at the tip of the protrusion 54 described above. For this reason, the air outlet 64 can be brought close to the first paper discharge roller unit 25, and the cooling performance of the paper can be further improved.

<Second Embodiment>
Next, a color printer 1 as an image forming apparatus according to the second embodiment will be described with reference to FIGS. 6 and 7. FIG. 6 is a cross-sectional view showing the upper part of the color printer according to the second embodiment of the present invention. FIG. 7 is a perspective view showing an IH coil unit in a color printer according to the second embodiment of the present invention. Hereinafter, the description of the same configuration as that of the first embodiment will be omitted as appropriate. In FIG. 6, the white arrow indicates the flow of cooling air, and the thick line S indicates the paper.

  As shown in FIG. 6, the first paper discharge tray 4 is disposed above each container 18, and the space between the container 18 and the first paper discharge tray 4 is partitioned vertically by a partition plate 71. Yes. A connection duct 72 is formed between the partition plate 71 and the first paper discharge tray 4 in the left-right direction. The connection duct 72 communicates with the sub duct 62 provided on the protrusion 54 of the first paper discharge tray 4, and the first duct that extends from the container cooling fan 47 to the air outlet 64 by the connection duct 72 and the sub duct 62. 73 is formed.

  An IH cooling fan 74 is installed on the right side of the rightmost container 18 between the partition plate 34 and the container 18 and the partition plate 71 between the container cooling fan 47 and the IH cooling fan 74. Two ducts 75 are formed.

  As shown in FIG. 7, the IH cooling fan 74 is connected to a cooling intake port 77 provided at the front end portion of the case member 41 of the IH coil unit 38 via an intake duct 76. A cooling exhaust port 78 is provided at the rear end of the case member 41 of the IH coil unit 38, and the cooling exhaust port 78 is connected to a space on the back side of the color printer 1 via an exhaust duct 80.

  In the configuration as described above, when the container cooling fan 47 and the IH cooling fan 74 are operated along with the image forming operation, the outside air introduced through the air inlet 56 of the louver 55 is sucked into the container cooling fan 47. The As shown in FIG. 6, the cooling air from the upper part of the container cooling fan 47 flows through the connection duct 72 from the left to the right. The cooling air flows into the sub duct 62 and is blown out from the blower port 64 toward the vicinity of the discharge nip 46 of the first paper discharge roller unit 25. The sheet conveyed to the first paper discharge roller unit 25 is cooled by the blown cooling air.

  Further, the cooling air from the lower part of the container cooling fan 47 flows through the second duct 75 from the left to the right. Each container 18 is cooled by the cooling air. The cooling air that has cooled each container 18 is sucked into the IH cooling fan 74. Then, it is sent from the IH cooling fan 74 to the intake duct 76 and flows into the IH coil unit 38 from the cooling intake port 77. Then, after flowing through the IH coil unit 38 from the front to the rear to cool the IH coil unit 38, the IH coil unit 38 flows into the exhaust duct 80 from the cooling exhaust port 78, and from the rear end of the exhaust duct 80 to the rear of the color printer 1. Discharged into space.

  In the present embodiment, similarly to the first embodiment, both the container 18 and the paper can be cooled by the cooling air from the container cooling fan 47. That is, the container cooling fan 47 can be used for cooling the paper. Therefore, it is possible to reduce the number of fans as compared with the case where a fan dedicated to cooling the paper is provided, and it is possible to reduce manufacturing costs, save space, and reduce noise.

  In addition, the IH coil unit 38 has a temperature specification in the induction heating coil 42, and the induction heating function increases as the temperature of the induction heating coil 42 decreases. Therefore, cooling of the IH coil unit 38 is essential. Therefore, in this embodiment, the cooling air from the container cooling fan 47 is sucked into the IH cooling fan 74, and the IH coil unit 38 is cooled by the cooling air from the IH cooling fan 74. With such a configuration, the cooling efficiency of the IH coil unit 38 can be increased.

  The temperature of the cooling air after cooling each container 18 rises somewhat, but the temperature is sufficiently lower than that of the IH coil unit 38. For this reason, it is possible to sufficiently cool the sheet.

  In addition, by dividing the space between the container 18 and the first paper discharge tray 4 up and down by the partition plate 71, air layers are formed above and below the partition plate 71, respectively. Therefore, heat from the sheets stacked on the first paper discharge tray 4 is not easily transmitted to the container 18 disposed below the second duct 75, and solidification of the toner in the container 18 can be prevented.

  In the first and second embodiments, the case where the air outlet 64 is provided only in the first paper discharge tray 4 has been described. However, in another different embodiment, the air outlet 64 is provided only in the second paper discharge tray 5. Alternatively, the air outlet 64 may be provided in both the first paper discharge tray 4 and the second paper discharge tray 5.

  In the first and second embodiments, the IH coil unit 38 is used as a means for heating the fixing device 23. However, in other different embodiments, the fixing device 23 is used by using other heating means such as a halogen heater. You may heat.

  In the first and second embodiments, the case where the configuration of the present invention is applied to the color printer 1 has been described. However, in other different embodiments, other image formation such as a monochrome printer, a copying machine, a facsimile machine, and a multifunction machine is performed. It is also possible to apply the configuration of the present invention to an apparatus.

1 Color printer (image forming device)
4 First paper discharge tray 18 Container 20 Transport path 23 Fixing device 25 First paper discharge roller unit 36 Heating roller 38 IH coil unit (heating means)
47 Container cooling fan 64 Air outlet 73 First duct 74 IH cooling fan (cooling fan for heating means)
75 Second duct 76 Intake duct 77 Cooling inlet 78 Cooling outlet 80 Exhaust duct

Claims (3)

A transport path for transporting the paper, a fixing device for fixing the toner image on the paper transported along the transport path, and the paper on which the toner image has been fixed by the fixing device is finally discharged to a paper discharge tray An image forming apparatus including a paper discharge roller unit,
The paper discharge tray is provided with a blowing port for sending cooling air toward the paper discharge roller unit,
The image forming apparatus includes:
A container that is disposed on the lower surface side of the paper discharge tray and contains toner;
A container cooling fan disposed on the lower surface side of the paper discharge tray for cooling the container;
The fixing device including a heating roller disposed along the conveyance path;
Provided in the fixing device, a heating means you heat the heating roller,
A cooling fan for heating means for cooling the heating means;
A first duct that reaches from the container cooling fan to the air blowing port without passing through the fixing device;
A second duct extending from the container cooling fan to the heating means cooling fan,
At one end in the longitudinal direction of the heating means, a cooling inlet to which the cooling fan for the heating means is connected is provided,
The other end in the longitudinal direction of the heating means is provided with a cooling exhaust port for discharging cooling air flowing from the cooling intake port,
The image forming apparatus, wherein the cooling intake port and the cooling exhaust port are provided on the same side as the heating roller with respect to the transport path.   The image forming apparatus according to claim 1, further comprising an air intake duct connecting the cooling fan for the heating unit and the cooling air inlet.   The image forming apparatus according to claim 1, further comprising an exhaust duct connecting the cooling exhaust port and a space on the back side of the apparatus.