JP2013064789A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of dew condensation on a conveying roller without using a fan to reduce noise.SOLUTION: An image forming apparatus 1 of the present invention includes: a fixing device 23 that fixes a toner image on a sheet; and a roller unit 29 that is arranged above the fixing device 23, and conveys a sheet on which a toner image is fixed in a predetermined direction. The roller unit 29 includes: a conveying roller 45 that is arranged along a conveying path 19, and provided in a rotatable manner; and a water absorption roller 47 that contacts the conveying roller 45, and is driven to rotate by the conveying roller 45.

Description

  The present invention relates to an electrophotographic image forming apparatus, and more particularly, to an image forming apparatus including a fixing device that fixes a toner image on a sheet, and a roller unit that conveys the sheet on which the toner image is fixed in a predetermined direction. Relates to the device.

  2. Description of the Related Art Conventionally, an electrophotographic image forming apparatus such as a copying machine or a printer is provided with a fixing device that heats and pressurizes a toner image and fixes the toner image onto a sheet, and a roller unit that conveys the sheet on which the toner image is fixed. It has been. This roller unit is arranged on the downstream side of the sheet conveyance path from the fixing device. For example, when duplex printing is not performed on the sheet, the roller unit conveys the sheet to the discharge tray and When duplex printing is performed, the sheet is conveyed to the reverse path.

  In the image forming apparatus having such a configuration, when the toner image is fixed on the paper by the fixing device, the water contained in the paper is discharged as water vapor, and is disposed on the downstream side of the conveyance path from the fixing device. May adhere to the surface of the member (particularly, the conveyance roller provided in the roller unit described above). When water vapor adheres to the surface of the conveyance roller in this manner, water vapor is accumulated as water droplets in the conveyance nip formed by the conveyance rollers, causing condensation, and the paper passing through the conveyance nip absorbs the water droplets. End up. When the paper absorbs water droplets in this way, the paper gets wet, and there is a risk of causing a transfer failure when performing double-sided printing on the paper.

  In order to solve such a problem, a configuration is known in which a hole for releasing water vapor generated in the fixing device is provided in the paper discharge unit. However, in the case of a structure in which the upper part of the paper discharge unit is blocked by the apparatus main body as in an MFP (multifunction machine), even if a hole is provided in the paper discharge unit, the flow of water vapor is poor, and the water vapor generated in the fixing device Cannot be fully discharged to the outside. Therefore, the problem that the paper absorbs water droplets still occurs.

  Thus, conventionally, there have been many countermeasures by forming an exhaust passage inside the apparatus and forcibly exhausting using a fan (see Patent Document 1).

JP 2011-59512 A

  However, with such a configuration, the addition of a fan increases the noise during sheet passing, making it difficult to reduce the noise.

  In view of the above circumstances, an object of the present invention is to reduce noise by preventing condensation on a transport roller without using a fan.

  An image forming apparatus of the present invention includes a fixing device that fixes a toner image on a sheet, and a roller unit that is provided above the fixing device and conveys the sheet on which the toner image is fixed in a predetermined direction. In the image forming apparatus, the roller unit is disposed along the conveyance path, and is rotatably provided with a conveyance roller that contacts the conveyance roller and rotates in accordance with the rotation of the conveyance roller. And a roller.

  By adopting such a configuration, it becomes possible to collect water vapor adhering to the surface of the transport roller by the water absorption roller, and it is possible to prevent condensation of the transport roller without using a fan. For this reason, it is possible to reduce noise compared to the case where a dew condensation countermeasure for the transport roller is performed using a fan. In addition, for example, it is possible to reduce the frictional resistance between the conveyance roller and the water absorption roller and suppress the generation of abnormal noise compared to the case where a sheet-like water absorption sponge is fixed and brought into contact with the conveyance roller. It is possible to further reduce noise. Moreover, it becomes possible to suppress that a conveyance roller contacts the same location of a water absorption roller, it becomes possible to suppress the fall of water absorption performance and to aim at the improvement of durability of a water absorption roller. In addition, it is not necessary to separately provide a means for driving the water absorption roller, and the configuration of the apparatus can be simplified.

  The image forming apparatus of the present invention may include an urging member that rotatably supports the water absorption roller and urges the water absorption roller toward the transport roller.

  By adopting such a configuration, it is possible to reduce the number of parts compared to a case where a member that rotatably supports the water absorption roller is provided separately from the urging member.

  In the image forming apparatus of the present invention, a conveyance guide may be provided between the fixing device and the roller unit, and a circulation hole may be provided in the vertical direction in the conveyance guide.

  By adopting such a configuration, hot air from the fixing device flows into the periphery of the roller unit through the circulation hole. Therefore, heat generated in the fixing device can be efficiently transmitted to the roller unit, and the water absorption roller is easily dried. Along with this, it is possible to avoid the disadvantage that the water in the water absorption roller is saturated and it becomes difficult to recover the water to the water absorption roller.

  In the image forming apparatus of the present invention, the water absorption roller may be disposed in a space whose upper side is sealed.

  By adopting such a configuration, it becomes difficult for hot air from the fixing device to escape outside the above-described space, and also in this respect, the water absorption roller is easily dried. Along with this, it is possible to avoid the disadvantage that the water in the water absorption roller is saturated and it becomes difficult to recover the water to the water absorption roller.

  In the image forming apparatus of the present invention, a hole for discharging water vapor generated in the fixing device to the outside may be formed above the fixing device.

  By adopting such a configuration, it becomes easy to discharge the water vapor generated in the fixing device to the outside, and in combination with the water absorption effect by the water absorption roller described above, the condensation on the surface of the conveyance roller is more effectively suppressed. It becomes possible.

  In the image forming apparatus of the present invention, the conveyance path on which the roller unit is provided may be a reverse path for double-sided printing.

  In such a roller unit provided along the reversing path for double-sided printing, if condensation occurs in the transport nip, moisture may adhere to the paper and transfer defects may occur during double-sided printing. Therefore, it is necessary to reliably suppress the adhesion of moisture to the paper using the configuration of the present invention. That is, the configuration of the present invention is suitable for a roller unit provided along a reverse path for double-sided printing.

  The present invention makes it possible to reduce noise by preventing condensation on the transport roller without using a fan.

1 is a schematic diagram illustrating an outline of a configuration of a multifunction peripheral according to an embodiment of the present invention. 1 is a cross-sectional view illustrating a fixing device and a downstream portion of the fixing device in a multifunction peripheral according to an embodiment of the present invention. FIG. 2 is a plan view showing a paper discharge unit in the multifunction machine according to the embodiment of the present invention. FIG. 5 is a cross-sectional view showing a periphery of a third roller unit in the multifunction machine according to the embodiment of the present invention. FIG. 5 is a perspective view showing the periphery of a third roller unit in the multifunction machine according to the embodiment of the present invention.

  First, the overall configuration of the multifunction machine 1 as an image forming apparatus will be described with reference to FIG. FIG. 1 is a schematic diagram illustrating an outline of a configuration of a multifunction peripheral according to an embodiment of the present invention.

  The multifunction device 1 includes a box-shaped multifunction device main body 2. A paper feed cassette 3 that stores paper (not shown) is provided at the lower portion of the multifunction device main body 2. A first paper discharge tray 4 is provided, and 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 multi-function device main body 2, and an exposure unit composed of a laser scanning unit (LSU) is provided below the intermediate transfer belt 6. 7 is provided, 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. Above the developing unit 11, four toner containers 18 corresponding to the image forming units 8 are provided for each toner color.

  A main path 20 that forms a part of the transport path 19 is provided on one side (the right side in the drawing) of the multifunction machine body 2. A paper feeding unit 21 is provided at the upstream end of the main 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 midstream part of the main path 20, downstream of the main path 20. The fixing device 23 is provided in the section. Details of the fixing device 23 will be described later.

  The main path 20 branches up and down at a portion downstream of the fixing device 23. At the downstream end of the lower branch path 24, a first roller unit 25 is provided on the upper side of the first paper discharge tray 4 (upper right side in the drawing), and at the downstream end of the upper branch path 26. The second roller unit 27 is provided on the upper one side (upper right side in the drawing) of the second paper discharge tray 5. Details of the first roller unit 25 and the second roller unit 27 will be described later. The second roller unit 27 is connected to a portion of the main path 20 upstream of the secondary transfer portion 22 via a reverse path 28 for duplex printing provided on one side (right side in the drawing) of the main path 20. Has been. In the present embodiment, the conveyance path 19 is configured by the main path 20, the branch paths 24 and 26, and the reverse path 28. A third roller unit 29 is provided at the upstream end of the reversing path 28. Details of the third roller unit 29 will be described later.

  Next, an image forming operation of the multifunction machine 1 having such a configuration will be described. When the MFP 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 multifunction machine 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 developing device 11 develops the electrostatic latent image into a toner image of a corresponding color with toner. 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 has been secondarily transferred is conveyed downstream through the main path 20 and enters the fixing device 23 where the toner image is fixed on the sheet. The sheet on which the toner image is fixed enters either the lower branch path 24 or the upper branch path 26. The paper that has entered the lower branch path 24 is discharged onto the first paper discharge tray 4 by the first roller unit 25. The sheet that has entered the upper branch path 26 is discharged onto the second sheet discharge tray 5 by the second roller unit 27 or is conveyed to the reverse path 28 for duplex printing.

  Next, the fixing device 23 and the first to third roller units 25, 27, and 29 will be described in detail mainly with reference to FIGS. FIG. 2 is a cross-sectional view illustrating a fixing device and a downstream portion of the fixing device in the multifunction peripheral according to the embodiment of the present invention. FIG. 3 is a plan view showing the paper discharge unit in the multifunction machine according to the embodiment of the present invention. FIG. 4 is a cross-sectional view showing the periphery of the third roller unit in the multifunction machine according to the embodiment of the present invention. FIG. 5 is a perspective view showing the periphery of the third roller unit in the multifunction machine according to the embodiment of the present invention. Hereinafter, for convenience, the near side in FIGS. 2 and 4 will be described as the front side (front side) of each member. In FIG. 3, the lower side is the front side (front side) of each member, and in FIG. 5, the left front side is the front side (front side) of each member.

  As shown in FIG. 2, the fixing device 23 includes a heating roller 30 and a pressure roller 31 provided on the right side of the heating roller 30.

  The heating roller 30 is composed of, for example, a roller body and a belt body provided around the roller body. The roller body is made of, for example, a cylindrical core material made of a metal such as aluminum or iron, an elastic layer made of silicon rubber or the like provided around the core material, and a fluorine resin such as PFA covering the elastic layer. A release layer. The belt body is made of, for example, a base material made of a ferromagnetic material such as Ni, an elastic layer made of silicon rubber or the like provided around the base material, and a fluororesin such as PFA covering the elastic layer. A release layer. The heating roller 30 is heated by an IH fixing unit (not shown).

  The pressure roller 31 includes, for example, a cylindrical core material made of a metal such as aluminum or iron, an elastic layer made of silicon rubber or the like provided around the core material, and fluorine such as PFA that covers the elastic layer. And a release layer made of resin. The pressure roller 31 is pressed against the heating roller 30 by an urging force of an urging means (not shown), and a fixing nip 33 is formed between the heating roller 30 and the pressure roller 31. Is configured to rotate following the rotation of the heating roller 30. Then, the sheet conveyed along the main path 20 is heated and pressed in the fixing nip 33 to fix the toner image on the sheet.

  The first roller unit 25 is disposed obliquely above the fixing device 23 (upper left in this embodiment). The first roller unit 25 includes a first drive roller 37 and a first driven roller 38 disposed above the first drive roller 37.

  The first drive roller 37 is connected to a drive source (not shown) via a plurality of gears (not shown), and is configured to rotate by a driving force from the drive source. The first driven roller 38 is in pressure contact with the first drive roller 37 and is configured to rotate following the rotation of the first drive roller 37. Then, by rotating the first driving roller 37 and the first driven roller 38, the sheet conveyed to the lower branch path 24 can be discharged to the first discharge tray 4 (see FIG. 1). It is configured.

  The second roller unit 27 is provided substantially above the fixing device 23 (more precisely, a position slightly to the left of the fixing device 23 above), and from the fixing device 23 rather than the first roller unit 25. It is separated.

  The second roller unit 27 includes a second drive roller 40 and a second driven roller 41 disposed above the second drive roller 40. The second drive roller 40 is connected to a drive source (not shown) via a plurality of gears (not shown), and is configured to rotate by a drive force from the drive source. The second driven roller 41 is in pressure contact with the second drive roller 40 and is configured to rotate following the second drive roller 40. Then, by rotating the second drive roller 40 and the second driven roller 41 in one direction, the sheet conveyed to the upper branch path 26 is discharged to the second discharge tray 5 (see FIG. 1). It is configured to be able to. On the other hand, by rotating the second driving roller 40 and the second driven roller 41 in the direction opposite to the one direction described above, the sheet conveyed to the upper branch path 26 can be switched back to the reversing path 28. It is configured as follows.

  The upper side of the second roller unit 27 is covered with a paper discharge unit 42. As shown in FIG. 3, a large number of slit-like long holes 43 are formed on the right side of the paper discharge unit 42. Each long hole 43 has a long shape in the left-right direction. As shown in FIG. 2, each elongated hole 43 is disposed above the fixing device 23. On the right side of the lower surface of the paper discharge unit 42, ribs 44 project from the formation intervals of the long holes 43. Each rib 44 has a shape that is long in the left-right direction, and a sheet that has been transported through the upper branch path 26 or a sheet that is switched back from the upper branch path 26 to the reversing path 28 is placed in each slot 43. Prevent clogging.

  The third roller unit 29 is disposed above the fixing device 23. A plurality of conveyance guides 73 exist between the fixing device 23 and the third roller unit 29, and a circulation hole 74 is formed in each conveyance guide 73 in the vertical direction.

  As best shown in FIG. 4, the third roller unit 29 is disposed at a lower left side of the third drive roller 45 as a transport roller provided along the reversing path 28. A third driven roller 46 and a water absorption roller 47 arranged on the right side of the third drive roller 45 are provided.

  The third drive roller 45 is rotatably supported by a right cover 48 that covers the right side surface of the multifunction machine main body 2. The third driving roller 45 is connected to a driving source (not shown) provided below the third roller unit 29 via a belt mechanism (not shown), and rotates by driving force from the driving source. It is configured as follows.

  The third driven roller 46 is in pressure contact with the third drive roller 45 to form a conveyance nip 51, and is driven to rotate as the third drive roller 45 rotates. Then, by rotating the third driving roller 45 and the third driven roller 46, the sheet conveyed to the upstream end of the reversing path 28 can be conveyed to the downstream side of the reversing path 28.

  The water absorption roller 47 is disposed in a space 54 whose upper side is sealed by an inner plate 50, an outer plate 52 (see FIG. 2) and an upper plate 53 of the right cover 48. The water absorption roller 47 includes a shaft member 55, an intermediate member 56 provided around the shaft member 55, and a water absorption member 57 provided around the intermediate member 56. The shaft member 55 and the intermediate member 56 are made of, for example, resin, and are integrated by four connection members 58 extending radially from the shaft member 55. The water absorbing member 57 is made of, for example, sponge and has a cylindrical shape. As best shown in FIG. 5, the water absorption roller 47 is formed to have substantially the same length as the third drive roller 45 and is arranged in the same direction as the third drive roller 45.

  The water absorption roller 47 is attached to a leaf spring 59 as an urging member. The plate spring 59 is formed by bending a sheet metal, and includes a side plate 60 provided so as to cover the right side surface of the water absorption roller 47, and a mounting plate 61 bent to the left from both front and rear ends of the side plate 60. And a connecting plate 62 that is bent rightward from the lower end of the side plate 60, and a fixed plate 63 that is bent downward from the right end of the connecting plate 62.

  Each mounting plate 61 has a through hole (not shown) drilled in the front-rear direction, and the front and rear ends of the shaft member 55 of the water absorption roller 47 are inserted into the through hole so that a leaf spring is inserted. A water absorption roller 47 is rotatably supported by 59.

  The leaf spring 59 is fixed to the inner plate 50 of the right cover 48. This fixing will be described. A bolt hole (not shown) is drilled in the left-right direction at the center of the fixing plate 63 in the front-rear direction, and boss holes 64 are drilled in the left-right direction on both sides of the bolt hole. . On the other hand, five protruding plates 65 project from the inner plate 50 of the right cover 48 toward the right. The central portions of the protruding plates 65 in the vertical direction are connected by a reinforcing plate 66 (see FIG. 4). The projecting plate 65 at the center in the front-rear direction is provided with a female screw portion (not shown), and bosses 67 project from the projecting plates 65 on both the front and rear sides of the projecting plate 65 at the center in the front-rear direction. . Then, in a state where each boss 67 is fitted in each boss hole 64 of the fixing plate 63, a bolt 68 inserted through the bolt hole of the fixing plate 63 is a female screw portion provided on the protruding plate 65 at the center in the front-rear direction. The leaf spring 59 is fixed to the inner plate 50 by being screwed to the inner plate 50.

  The water absorption roller 47 is pressed against the third drive roller 45 by being biased toward the third drive roller 45 by the leaf spring 59. When the third drive roller 45 rotates, the water absorption roller 47 is driven by this rotation. 47 is configured to rotate.

  The reversing path 28 is provided with fourth to sixth roller units 70 to 72 (see FIG. 1) below the third roller unit 29. The fourth roller unit 70 is disposed obliquely above and to the right of the fixing device 23. Since the configuration of the fourth to sixth roller units 70 to 72 is the same as that of the third roller unit 29 except that the water absorption roller 47 is not provided, the description thereof is omitted.

  In the above configuration, during the image forming operation, when the toner image is fixed on the paper by the fixing device 23, the water contained in the paper is released as water vapor. A part of this water vapor is discharged to the outside through the long holes 43 provided in the paper discharge unit 42. Further, another part of the water vapor described above flows through the gap between the conveyance guides 73 and the like to the upper side of the fixing device 23 and adheres to the surface of the third drive roller 45 of the third roller unit 29. The water vapor attached to the surface of the third drive roller 45 is collected by the water absorption roller 47 and removed from the surface of the third drive roller 45. The water vapor collected by the water absorption roller 47 is dried by the heat generated in the fixing device 23.

  In this embodiment, since the water vapor adhered to the surface of the third drive roller 45 is collected by the water absorption roller 47 in this way, it is possible to prevent the condensation of the third drive roller 45 without using a fan. It becomes. For this reason, it is possible to reduce noise compared to the case where the fan is used to prevent condensation of the third drive roller 45.

  Further, since the water absorption roller 47 is configured to rotate following the rotation of the third drive roller 45, for example, compared with a case where a sheet-like water absorption sponge is fixed and brought into contact with the third drive roller 45, for example. Thus, it is possible to reduce the frictional resistance between the third drive roller 45 and the water absorption roller 47, and it is possible to further reduce noise by suppressing the generation of abnormal noise. Moreover, it becomes possible to suppress that the 3rd drive roller 45 continues contacting the same location of the water absorption roller 47, and it can suppress the fall of water absorption performance and can aim at the improvement of durability of the water absorption roller 47. Become. In addition, it is not necessary to separately provide a means for driving the water absorption roller 47, and the configuration of the apparatus can be simplified.

  The leaf spring 59 has both a function of urging the water absorption roller 47 toward the third drive roller 45 and a function of supporting the water absorption roller 47 in a rotatable manner. Therefore, it is possible to reduce the number of parts compared to a case where a member that rotatably supports the water absorption roller 47 and a member that urges the water absorption roller 47 toward the third drive roller 45 are provided separately.

  Further, in the present embodiment, a circulation hole 74 is formed in each conveyance guide 73, and hot air from the fixing device 23 flows into the periphery of the third roller unit 29 through the circulation hole 74 (one point in FIG. 2). (See chain arrow X). Therefore, the heat generated in the fixing device 23 can be efficiently transmitted to the third roller unit 29, and the water absorption roller 47 is easily dried. Accordingly, it is possible to avoid the inconvenience that the water in the water absorption member 57 of the water absorption roller 47 is saturated and the recovery of the water to the water absorption roller 47 becomes difficult.

  Further, the water absorption roller 47 is disposed in the space 54 sealed on the upper side, so that hot air from the fixing device 23 is difficult to escape to the outside of the space 54 described above, and also in this respect, the water absorption roller 47 can be easily dried. Become.

  Further, in the present embodiment, since the elongated hole 43 is formed in the paper discharge unit 42, the water vapor generated in the fixing device 23 is easily discharged to the outside, and combined with the water absorption effect by the water absorption roller 47 described above. In addition, it is possible to more effectively suppress condensation on the surface of the third drive roller 45.

  In the present embodiment, the configuration of the present invention is applied to the third roller unit 29 provided in the reversing path 28. As described above, when dew condensation occurs in the transport nip 51 in the third roller unit 29 provided along the reversing path 28, moisture may adhere to the paper and transfer defects may occur during duplex printing. Therefore, it is necessary to reliably suppress the adhesion of moisture to the paper using the configuration of the present invention. That is, the configuration of the present invention is suitable for the third roller unit 29 provided along the reverse path 28.

  In the present embodiment, the case where the water absorption roller 47 is brought into contact with only the third driving roller 45 among the pair of rollers (the third driving roller 45 and the third driven roller 46) provided in the third roller unit 29 has been described. In other different embodiments, the water absorption roller 47 may be brought into contact only with the third driven roller 46, or the water absorption roller 47 may be brought into contact with both the third drive roller 45 and the third driven roller 46. That is, the “conveying roller” includes not only the third driving roller 45 but also the third driven roller 46.

  In the present embodiment, the case where the configuration of the present invention is applied to the third roller unit 29 provided in the reversing path 28 has been described. However, in another different embodiment, the first roller unit 25, the second roller unit 27, the second You may apply the structure of this invention to other different roller units, such as 4 roller unit 70. FIG. In other words, the “conveying roller” includes all rollers provided in the roller unit above the fixing device 23 and used for conveying the paper.

  In particular, since the second roller unit 27 is disposed substantially above the fixing device 23, water vapor is likely to accumulate, and since the second roller unit 27 is separated from the fixing device 23 compared to the first roller unit 25, each roller Water vapor attached to the surfaces of 40 and 41 is difficult to dry. Therefore, the effect by applying the structure of this invention is high.

  In the present embodiment, the case where the sponge water-absorbing member 57 is used has been described. However, in another different embodiment, for example, the water-absorbing member 57 formed of other different materials such as felt and polymer absorbent material may be used. good.

  In the present embodiment, the case where the water absorbing roller 47 is configured by the three-layer structure of the shaft member 55, the intermediate member 56, and the water absorbing member 57 has been described. However, in other different embodiments, the shaft member 55 and the water absorbing member 57 It is also possible to form the water absorption roller 47 with a two-layer structure, or to form the water absorption roller 47 with only the water absorption member 57.

  In the present embodiment, the case where the plate spring 59 is used as the biasing member has been described. However, in another different embodiment, another different biasing member such as a coil spring may be used.

  In the present embodiment, the member that rotatably supports the water absorption roller 47 and the member that urges the water absorption roller 47 toward the conveyance roller such as the third drive roller 45 are the same member (plate spring 59). In a different embodiment, a member that rotatably supports the water absorption roller 47 and a member that urges the water absorption roller 47 toward the conveyance roller such as the third drive roller 45 may be provided separately.

  In this embodiment, the IH fixing unit is used as a means for heating the heating roller 30, but in another different embodiment, the heating roller 30 may be heated using another heating means such as a halogen heater.

  In the present embodiment, the case where the configuration of the present invention is applied to the multifunction device 1 has been described. However, in another different embodiment, the present invention is applied to other image forming apparatuses such as a color printer, a monochrome printer, a copying machine, and a facsimile. It is also possible to apply a configuration.

1 MFP (image forming device)
19 Transport path 23 Fixing device 28 Reverse path 29 Third roller unit 43 Slot (hole)
45 Third drive roller (conveyance roller)
47 Water absorption roller 54 Space 59 Leaf spring (biasing member)
74 Transport Guide

Claims (6)

An image forming apparatus comprising: a fixing device that fixes a toner image on a sheet; and a roller unit that is provided above the fixing device and conveys the sheet on which the toner image is fixed in a predetermined direction.
The roller unit is
A transport roller disposed along the transport path and rotatably provided;
An image forming apparatus comprising: a water absorption roller that contacts the conveyance roller and rotates in accordance with the rotation of the conveyance roller.   The image forming apparatus according to claim 1, further comprising an urging member that rotatably supports the water absorption roller and urges the water absorption roller toward the conveying roller.   The image forming apparatus according to claim 1, wherein a conveyance guide is provided between the fixing device and the roller unit, and a circulation hole is provided in the conveyance guide in a vertical direction.   The image forming apparatus according to claim 1, wherein the water absorption roller is disposed in a space whose upper side is sealed.   The image forming apparatus according to claim 1, wherein a hole for discharging water vapor generated by the fixing device to the outside is formed above the fixing device.   The image forming apparatus according to claim 1, wherein the conveyance path on which the roller unit is provided is a reverse path for double-sided printing.