JP2005084109A - Image forming method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method whereby an image having gloss which a user desires is obtained even when an intermediate or high speed apparatus is used and a gloss difference hardly occurs between the sides of an output which has images on both sides, and to provide an apparatus therefor. <P>SOLUTION: The image forming method consists of: an image forming step in which an unfixed toner image formed with toner the main component of the binder of which is resin by an image forming means 1 is transferred onto a recording medium; a primary fixing step in which the recording medium carrying the unfixed toner image held on it is passed through a first fixing device 2 and the toner image is fixed to the recording medium under heat and pressure; a secondary fixing step in which the toner image is re-heated by a secondary fixing device 30 after the primary fixing step; and a cooling step in which the toner image heated in the secondary fixing step is cooled by a cooling device. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming method and apparatus for forming an image using toner whose main component is a resin.

  In image forming apparatuses such as electrophotographic copying machines, laser beam printers, facsimile machines, and multifunction machines having at least two of these functions, full-color image output has become common in recent years. And for outputting graph images, it is preferable to output a matte image without gloss because the line image is easier to see. Also, when outputting photographic images such as advertisements and designs, the higher the glossiness of the images, the higher the image quality is preferred.

  Incidentally, the glossiness of an image obtained by an electrophotographic image forming apparatus depends on the surface irregularity state of the toner at the time of fixing. That is, as the surface irregularity of the fixing toner becomes more intense, the matte image becomes dull, and as the irregularity becomes smaller, the image becomes higher glossy. The surface irregularity state of the fixing toner is related to the state when the recording medium is separated from the fixing member. In an apparatus using a fixing roller as a fixing member, when the recording medium is separated from the fixing member, the surface of the toner image is separated from the fixing roller in a soft state. . In an apparatus using a fixing roller as a fixing member, when a glossy image is to be obtained, a sufficient heat must be applied at a low speed and the fixing member must have a smooth surface roughness. However, even if the surface roughness of the fixing member can be maximized, the glossiness deteriorates when the linear velocity exceeds 200 mm / sec, and a glossy image cannot be obtained when the linear velocity exceeds 300 mm / sec.

  In a medium-to-high speed image forming apparatus with a recording medium conveyance speed of 200 mm / sec or more, a nip is formed by press contact between the fixing member and the pressure member in order to obtain reliable fixing performance even if the fixing apparatus is medium-to-high speed conveyance. Heating means for controlling the nip to an appropriate temperature, and passing the recording medium carrying the unfixed toner image through the nip so that the toner image is in contact with the fixing member. As a result, an image that is configured to fix an unfixed toner image on a recording medium is used. However, when the fixing device having such a configuration is used, since the solidified state of the toner is incomplete when the recording medium is separated from the fixing member as described above, the toner surface becomes a matte image with irregularities. Is inevitable.

JP-A-9-190099 JP 2001-5319 A JP 2002-278356 A

  In the above-mentioned document 1, after the first fixing, the sheet is brought into close contact with the belt and conveyed, and the gloss mode of the image is switched by sub pressurization and OFF / ON of air blowing. However, in such a configuration, there is a problem that the glossiness on the back surface changes when there are images on both surfaces.

  In the document 2, the first fixing unit and the second fixing unit as necessary are provided to prevent fixing failure due to the type of paper, but the gloss finish cannot be controlled.

  In Document 3, the thickness of the recording paper is detected and the heating temperature is controlled to be constant, and the gloss is controlled by the temperature, contact state, etc. of the second fixing unit. However, in such a configuration, there is a problem that even when gloss control is unnecessary, the sheet passes through the first fixing and the second fixing, and extra power is consumed.

  SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming method and apparatus capable of obtaining an image having a glossy finish desired by a user even in a medium-to-high speed machine, and causing little variation in glossiness on both sides in double-sided image output. Yes.

  In order to solve the above problems, the present invention carries an image forming step of transferring an unfixed toner image formed using a toner whose main component of a binder is a resin onto a recording medium, and an unfixed toner image A primary fixing step of passing a recording medium and fixing the toner image on the recording medium by heating and pressurization, a secondary fixing step of reheating the toner image after the primary fixing step, and the secondary fixing And a cooling process for cooling the toner image heated in the process.

  In order to solve the above problems, the present invention provides a single-sided image forming step of transferring an unfixed toner image formed using a toner whose main component of a binder is a resin onto one side of a recording medium, A primary single-side fixing step of passing a recording medium carrying a toner image and fixing the toner image to the recording medium by heating and pressurization, and an unfixed toner on the other side of the recording medium after the primary single-side fixing step The other side image forming process for transferring the image, and the primary other side fixing for passing the recording medium carrying the unfixed toner image on the other side and fixing the toner image on the other side of the recording medium by heating and pressing. A secondary fixing step for reheating the toner images on both sides of the recording medium after the primary other side fixing step, and a cooling step for cooling the toner images on both sides of the recording medium heated by the secondary fixing step; It is characterized by consisting of.

In the image forming method of the present invention, it is effective that the linear conveying speed of the recording medium is 200 mm / sec or more.
Furthermore, in the image forming method of the present invention, it is effective to control the glossiness of the fixed image by the heating temperature in the secondary fixing step.

Furthermore, in the image forming method of the present invention, it is effective to control the glossiness of the fixed image by the cooling temperature in the cooling step.
In order to solve the above problems, the present invention includes a heating unit that forms a nip with a fixing member and a pressure member and controls the nip to an appropriate temperature, and passes a recording medium carrying a toner image through the nip. A first fixing device that fixes a toner image on a recording medium by paper and a downstream of the first fixing device in the recording medium conveyance direction, a nip is formed by a fixing member and a facing member, and the nip is appropriately A second fixing device for reheating the toner image by passing through the nip a recording medium on which the toner image has been fixed by the first fixing device; And a cooling device for cooling the heated toner image.

  In order to solve the above problems, the present invention includes a heating unit that forms a nip with a fixing member and a pressure member and controls the nip to an appropriate temperature, and passes a recording medium carrying a toner image in the nip. A first fixing device that fixes a toner image on a recording medium by paper and a downstream of the first fixing device in the recording medium conveyance direction, a nip is formed by a fixing member and a facing member, and the nip is appropriately A second fixing device that includes heating means for controlling the temperature, and that reheats the toner images on both sides by passing the recording medium on which the toner images are fixed on both sides by the first fixing device through the nip; And a cooling device for cooling the toner images on both sides heated by the fixing device.

  In the image forming apparatus of the present invention, it is advantageous that the second fixing device has a fixing belt wound around a fixing roller that conveys the recording medium in close contact with a running surface and an exit roller as the fixing member. Is.

  Furthermore, in the image forming apparatus of the present invention, the second fixing device includes a counter belt wound around a counter roller and a counter outlet roller that convey the recording medium in close contact with the traveling surface as the counter member. It is effective.

  Furthermore, in the image forming apparatus of the present invention, it is effective that the fixing belt and the opposing belt have a ten-point average roughness (Rz) of 5.0 μm or less as the surface roughness.

  Furthermore, in the image forming apparatus of the present invention, it is effective that the cooling device is provided with heat pipes on the outlet roller and the opposite outlet roller of the second fixing device.

  Still further, in the image forming apparatus of the present invention, the cooling device is disposed between the fixing roller, the exit roller, the opposing roller, and the opposing exit roller of the second fixing device, and the respective back surfaces of the fixing belt and the opposing belt. It is effective to have a heat sink that abuts at.

  Furthermore, in the image forming apparatus of the present invention, the first fixing device is disposed in an image forming apparatus main body in which the image forming unit is disposed, and the second fixing device is independent from the image forming apparatus main body. In addition, it is effective to be configured as a unit that is selectively attached to the inside of the image forming apparatus main body.

  Furthermore, in the image forming apparatus of the present invention, it is effective that the cooling device is provided in the unit of the second fixing device.

  According to the present invention, a high-gloss image can be output even in a medium-to-high-speed image forming apparatus, and even if the output image is a double-sided image, a good image without high-gloss variation on the front and back sides can be obtained. can get. Furthermore, according to the present invention, an image output with glossiness controlled can be obtained.

Embodiments of the present invention will be described below with reference to the drawings. First, an example of the image forming apparatus according to the present invention will be clarified.
FIG. 1 is a schematic view showing a color copying machine as an example of an image forming apparatus. The image forming apparatus shown here includes an image forming unit 1 that forms a toner image on a recording medium, and a fixing device 2 that fixes the toner image on the recording medium.

  The image forming means 1 shown in FIG. 1 has first to fourth image carriers 3Y, 3M, 3C, 3BK configured as drum-shaped photosensitive members, and a yellow toner image is formed on each of the image carriers. A magenta toner image, a cyan toner image, and a black toner image are formed. An intermediate transfer belt 4 is disposed to face the first to fourth image carriers 3Y to 3BK, and the intermediate transfer belt 4 is wound around rollers 5, 6 and 7, and one of the rollers is illustrated. It is driven to run in the direction of arrow A by being driven to rotate by no drive means.

  Since the operation of forming the toner image on each of the first to fourth image carriers 3Y, 3M, 3C, and 3BK is substantially the same, the toner image is applied to the first image carrier 3Y. Only the structure to be formed will be described. The image carrier 3Y is driven to rotate counterclockwise in FIG. 1, and at this time, the surface of the image carrier is uniformly charged to a predetermined polarity by the charging roller 8. Then, the charged surface is irradiated with a light-modulated laser beam L emitted from the laser writing unit 9. As a result, an electrostatic latent image is formed on the image carrier 3Y, and the electrostatic latent image is visualized as a yellow toner image by the developing device 10. A transfer roller 11 is disposed at a position almost opposite to the image carrier 3Y across the intermediate transfer belt 4, and a voltage having a polarity opposite to the charging polarity of the toner on the image carrier 3Y is applied to the transfer roller 11. As a result, the yellow toner image on the image carrier 3Y is transferred onto the intermediate transfer belt 4. The residual transfer toner that is not transferred to the intermediate transfer belt 4 and remains on the image carrier 3Y is removed by the cleaning device 12.

  In exactly the same manner, magenta toner images, cyan toner images, and black toner images are respectively formed on the second to fourth image carriers 3M, 3C, 3BK, and these toner images are transferred with yellow toner images. The images are sequentially superimposed and transferred onto the intermediate transfer belt 4.

  On the other hand, a recording medium P made of, for example, transfer paper, a resin sheet, a resin film, or the like is fed from a paper feeding unit 13 provided below the image forming unit 1, and the recording medium P is indicated by an arrow B as shown in FIG. Then, it is fed toward the roller 7 of the intermediate transfer belt 4. A secondary transfer roller 14 is disposed substantially opposite the roller 7 with the intermediate transfer belt 4 interposed therebetween, and the recording medium P is sent between the intermediate transfer belt 4 and the secondary transfer roller 14. A voltage having a polarity opposite to the charging polarity of the toner is applied to the secondary transfer roller 14, whereby the superimposed toner image on the intermediate transfer belt 4 is transferred onto the recording medium P. The transfer residual toner that is not transferred to the recording medium P and remains on the intermediate transfer belt 4 is removed by an intermediate transfer belt cleaning device (not shown).

  The recording medium P carrying the four-color unfixed toner images in this way is sent to the fixing device 2 through the conveying means 15 as indicated by an arrow C, and at this time, the toner image is fixed on the recording medium P. Is done.

  The fixing device 2 shown in FIG. 1 is a heat roller type fixing device, and has a fixing member configured as a fixing roller 20 and a pressure member configured as a pressure roller 21 in pressure contact with the fixing roller 20. The rollers 20 and 21 are pressed against each other to form a nip. The fixing roller 20 is rotated in the clockwise direction, and the pressure roller 21 is rotated in the counterclockwise direction following the rotation of the fixing roller 20.

  The nip where the two rollers 20 and 21 are in pressure contact is controlled to an appropriate temperature suitable for fixing the toner image by the heating means. In this example, a halogen heater 22 as a heat source is provided inside the fixing roller 20, and a thermistor (not shown) is provided on or near the surface of the fixing roller 20, and the thermistor is heated by the heater 22. The surface temperature of the fixing roller 20 is detected, the heater 22 is turned on and off based on the detection result, and the surface temperature of the fixing roller 20 is controlled to an appropriate temperature, for example, 190 ° C. The toner used has a softening point of 90 ° C. and a minimum fixing temperature of 95 ° C. As the heating means, a resistance heating element or a non-contact radiant heat from a heat source may be used.

  As described above, the recording medium P carrying the unfixed toner image is sent to the fixing device 2 as indicated by the arrow C, and the recording medium P is oriented so that the toner image T is in contact with the surface of the fixing roller 12. At this time, the unfixed toner image is fixed on the recording medium P by heat and pressure.

  By the way, the image forming apparatus of the present embodiment conveys the recording medium P at a high linear velocity of 500 mm / sec, and the fixing device 2 is sufficiently applicable to such high-speed conveyance. And good fixability can be secured. However, in such a fixing device 2, since the toner surface is separated from the fixing roller 20 in a soft state, a non-glossy image is inevitable.

Therefore, in the image forming apparatus of the present embodiment, a second fixing device 30 is provided as shown in FIG. 1 in order to obtain a gloss image desired by the user.
FIG. 2 is an enlarged explanatory view of the second fixing device 30. In FIG. 2, the second fixing device 30 includes a fixing belt 31 wound around a heating roller 32 and an outlet roller 33 as a fixing member, a lower heating roller 42 as an opposing member, and a lower outlet roller 43 as an opposing outlet roller. It has a counter belt 41 wound around it. The heating roller 32, the lower heating roller 42, the outlet roller 33, and the lower outlet roller 43 are pressed against each other via the fixing belt 31 and the opposing belt 41, respectively, so that a nip from the heating roller 31 to the outlet roller 33 is formed. . Any one of the heating roller 31, the lower heating roller 41, the outlet roller 33, and the lower outlet roller 43 is a driving roller, whereby the fixing belt 31 is rotated in the clockwise direction and the opposing belt 41 is rotated in the counterclockwise direction.

  The nip between the fixing belt 31 and the opposing belt 41 is controlled to a temperature suitable for remelting of the toner image by a heating unit provided on the heating roller 31 and the lower heating roller 41 on the entrance side. In this example, halogen heaters 34 and 44 as heat sources are provided inside the heating roller 32 and the lower heating roller 41, respectively, and a thermistor (not shown) is provided on the surface of the fixing belt 31 and the opposing belt 41 or in the vicinity thereof. The thermistors detect the temperatures of the surfaces of the fixing belt 31 and the opposing belt 41 heated by the heaters 34 and 44, respectively, and turn on and off the heaters 34 and 44 based on the detection results. And the temperature of the surface of the part wound around the heating roller 32 and the lower heating roller 42 of the opposing belt 41 is controlled. As the heating means, other than that which can heat the entrance side of the second fixing device 30, a resistance heating element or a non-contact radiant heat of a heat source may be used.

  Further, the second fixing device 30 does not need to completely dissolve the toner unlike the fixing device 2 and only needs to be able to melt the surface of the toner image. Therefore, the surface temperature of the belt is slightly higher than the temperature of the softening point of the toner (90 ° C.). It is controlled to a high value, for example, 110 ° C. The second fixing device 30 uses the same specifications for the fixing belt 31 and the opposing belt 41, the heating roller 32 and the lower heating roller 42, and the outlet roller 33 and the lower outlet roller 43 so that they can be applied to a double-sided image to be described later. ing.

  In order to obtain a glossy image, it is important that the toner surface is solidified when the recording medium P is separated from the fixing belt 31. Therefore, in the present embodiment, the recording medium P is provided with a cooling device at the position of the exit roller 33 and the lower exit roller 43 that are separated from the fixing belt 31.

  The cooling device of this example is configured by heat pipes 51 and 52 respectively incorporated in the outlet roller 33 and the lower outlet roller 43, and the heat pipes 51 and 52 have heat radiating fins 53 exposed to the outside air as shown in FIG. Is provided.

  In the present embodiment, the second fixing device 30 can be incorporated in the main body of the image forming apparatus, but in the example of FIG. 1, an independent unit U is configured together with the cooling device. This unit U is an optional unit independent from the image forming apparatus main body, and can be selectively attached to a paper discharge port of the image forming apparatus main body. Therefore, the user can select disposal of the unit U according to the type that occupies most of the output images. That is, it is not necessary for users with many characters and graphs, and is very effective for users with many photographic image outputs.

  In the image forming apparatus configured as described above, the recording medium P on which the toner image is fixed by the fixing device 2 corresponding to the first fixing device provided in the image forming apparatus main body as described above is second from the direction of the arrow C. Enter the fixing device 30. The recording medium P that has entered the second fixing device is sandwiched between the fixing belt 31 and the opposing belt 41, and the toner image is heated at the position of the heating roller 32 and remelted. Thereby, the unevenness of the surface of the toner image formed by the fixing device 2 is eliminated. Thereafter, the remelted recording medium P is radiated by the idle running path 35 from the heating roller 32 to the outlet roller 33 and cooled by the outlet roller 33. Therefore, the re-melted toner image returns to a solidified state when separated from the fixing belt 31, so that a highly glossy image with less unevenness on the surface of the toner image can be output. The recording medium P that passes through the second fixing device 30 adheres to the fixing belt 31 and undergoes a process of melting, cooling, and solidification, so that the surface of the fixing belt 31 is transferred to the toner image. Therefore, by setting the ten-point average roughness (Rz) to 5.0 μm or less as the surface roughness of the fixing belt 31, a high-gloss image having a reflectance of 50 to 30% can be output.

  When the recording medium P that has been fixed by the fixing device 2 is sent to the second fixing device 30, the solidified toner image is remelted and cooled. Therefore, since the toner surface is solidified when separated from the fixing belt 31, a high gloss image can be output even at high speed conveyance.

  Incidentally, the image forming apparatus shown in FIG. 1 has a double-sided function. When a double-sided image is selected, the recording medium P that has passed through the fixing device 2 is conveyed to the double-sided conveyance path 17 by the switching unit 16. Although not shown, the double-sided conveyance path 17 is provided with a sheet reversing mechanism and a re-feeding mechanism, and the recording medium P re-feeded to the image forming means 1 via the double-sided conveyance path 17 is A toner image is formed on the back surface, and is fixed by the fixing device 2 after the formation.

  In this way, when the recording medium P having the toner images formed on both sides thereof is conveyed to the second fixing device 30, both sides can be output as a high gloss image. That is, the fixing belt 31 and the opposite belt 41, the heating roller 32 and the lower heating roller 42, the exit roller 33 and the lower exit roller 43 are the same, and the recording medium P is remelted on both sides of the toner image. Since it passes through the second fixing device 30 through a cooling and solidification process, both sides of the image become highly glossy images. Moreover, the glossiness of the output double-sided image does not vary.

  The control of the glossiness of the toner image from the image forming apparatus will be described. The glossiness of the toner image changes depending on the temperature at which the toner image is remelted by the second fixing device 30. That is, the unevenness formed on the surface of the toner image by the fixing device 2 disappears when the remelting temperature is set to a high value, so that the glossiness is increased. However, if the remelting temperature is too high, solidification of the toner becomes incomplete at the time of separation and the glossiness is lowered, so that the upper limit temperature is determined automatically. If the remelting temperature is set to a low value, the unevenness formed on the surface of the toner image remains somewhat, so that the glossiness is slightly lowered. In the image forming apparatus, when the remelting temperature is set to 120 ° C., a color image with a high gloss of 40% reflectance is obtained, and when the remelting temperature is set to 100 ° C., the reflectance is 15%. A glossy color image was obtained.

In the image forming apparatus, the glossiness of the toner image can be controlled by the cooling temperature of the cooling device, and an example thereof will be described.
For example, in the heat pipes 51 and 52 provided with the radiation fins 53 shown in FIG. 3, as shown in FIG. 2, fans 54 and 55 for blowing air toward the radiation fins 53 are provided. The cooling temperature can be adjusted by turning OFF. When the belt temperature at the exit is set to 60 ° C. for high gloss and 80 ° C. for medium gloss, a high quality color image output with a reflectance of 45% for high gloss and a reflectance of 20% for medium gloss is obtained. It became possible.

  FIG. 4 is an explanatory view showing another embodiment of the cooling device. The cooling device of this example is configured such that the heat sink is in contact with the back surface of the idle belt 35 between the fixing belt 31 and the opposing belt 41, that is, inside the loop. 61 and 62 are provided. The fixing belt 31 and the opposing belt 41 are cooled by the heat sinks 61 and 62, and the toner image of the recording medium P discharged from the second fixing device 30 can be solidified. Further, air cooling fans 63 and 64 for blowing air to the fins of the heat sinks 61 and 62 are provided, and the belt temperature at the outlet is adjusted by ON / OFF control thereof. When the belt temperature at the exit is set to 70 ° C. for high gloss and 90 ° C. for medium gloss, high-quality color image output with a reflectance of 40% for high gloss and a reflectance of 15% for medium gloss is possible. It became possible.

1 is a schematic explanatory diagram of an image forming apparatus showing an embodiment of the present invention. FIG. 10 is an explanatory diagram illustrating an example of a second fixing device. It is explanatory drawing which shows an example of a cooling device. FIG. 6 is an explanatory diagram of a second fixing device showing a second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming means 2 Fixing device (1st fixing device)
20 Fixing roller (fixing member)
21 Pressure roller (pressure member)
22 Halogen heater (heating means)
30 Second fixing device 31 Fixing belt (fixing member)
32 Heating roller (heating means)
33 Outlet roller (heating means)
41 Opposing belt (opposing member)
42 Lower heating roller (heating means)
43 Lower outlet roller 51, 52 Heat pipe (cooling device)
61, 62 Heat sink (cooling device)
P Recording medium

Claims (14)

An image forming step of transferring an unfixed toner image formed using a toner whose main component of the binder is a resin onto a recording medium;
A primary fixing step of passing a recording medium carrying an unfixed toner image and fixing the toner image to the recording medium by heating and pressurization;
A secondary fixing step of reheating the toner image after the primary fixing step;
A cooling step for cooling the toner image heated in the secondary fixing step;
An image forming method comprising: A single-sided imaging step of transferring an unfixed toner image formed using a toner whose main component of the binder is a resin onto one side of a recording medium;
A primary single-side fixing step of passing a recording medium carrying an unfixed toner image through and fixing the toner image to the recording medium by heating and pressurization;
After the primary one-side fixing step, an other-side image forming step of transferring an unfixed toner image to the other side of the recording medium;
A primary other side fixing step of passing a recording medium carrying an unfixed toner image on the other side and fixing the toner image on the other side of the recording medium by heating and pressing;
A secondary fixing step of reheating the toner images on both sides of the recording medium after the primary other side fixing step;
A cooling step for cooling the toner images on both sides of the recording medium heated by the secondary fixing step;
An image forming method comprising:   3. The image forming method according to claim 1, wherein the recording medium has a linear conveying speed of 200 mm / sec or more.   3. The image forming method according to claim 1, wherein the glossiness of the fixed image is controlled by the heating temperature in the secondary fixing step.   3. The image forming method according to claim 1, wherein the glossiness of the fixed image is controlled by the cooling temperature in the cooling step. The fixing member and the pressure member form a nip, and heating means for controlling the nip to an appropriate temperature is provided. The toner image is fixed on the recording medium by passing the recording medium carrying the toner image through the nip. A first fixing device;
Provided on the downstream side of the first fixing device in the recording medium conveying direction, the fixing member and the opposing member form a nip, and heating means for controlling the nip to an appropriate temperature is provided. The toner image is fixed by the first fixing device. A second fixing device that reheats the toner image by passing the recorded recording medium through the nip; and
A cooling device for cooling the toner image heated by the second fixing device;
An image forming apparatus comprising: The fixing member and the pressure member form a nip, and heating means for controlling the nip to an appropriate temperature is provided. The toner image is fixed on the recording medium by passing the recording medium carrying the toner image through the nip. A first fixing device;
Provided on the downstream side of the first fixing device in the recording medium conveying direction, the fixing member and the opposing member form a nip, and heating means for controlling the nip to an appropriate temperature is provided. A toner image is formed on both sides by the first fixing device. A second fixing device that reheats the toner images on both sides by passing the recording medium on which the toner is fixed through the nip;
A cooling device for cooling the toner images on both sides heated by the second fixing device;
An image forming apparatus comprising:   8. The image forming apparatus according to claim 6, wherein the second fixing device includes a fixing belt wound around a fixing roller that conveys the recording medium in close contact with a running surface and an exit roller as the fixing member. An image forming apparatus.   9. The image forming apparatus according to claim 6, wherein the second fixing device is wound around a counter roller and a counter outlet roller that transport the recording medium in close contact with the traveling surface as the counter member. An image forming apparatus having the opposed belt.   10. The image forming apparatus according to claim 8, wherein the fixing belt and the opposing belt have a ten-point average roughness (Rz) of 5.0 μm or less as a surface roughness. 10.   8. The image forming apparatus according to claim 6, wherein the cooling device is provided with heat pipes on the outlet roller and the counter outlet roller of the second fixing device.   8. The image forming apparatus according to claim 6, wherein the cooling device is provided between the fixing roller, the exit roller, the opposing roller, and the opposing exit roller of the second fixing device, and each of the fixing belt and the opposing belt. An image forming apparatus comprising: a heat sink that abuts on the back side.   8. The image forming apparatus according to claim 6, wherein the first fixing device is disposed in an image forming apparatus main body in which the image forming unit is disposed, and the second fixing device is independent from the image forming apparatus main body. The image forming apparatus is configured as a unit that is selectively attached to the inside of the main body of the image forming apparatus.   14. The image forming apparatus according to claim 13, wherein the cooling device is provided in a unit of the second fixing device.

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