JP4993671B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus having a configuration for cooling a conveyance path for conveying a sheet on which an image is formed after heat fixing.

In the image forming apparatus using the heat fixing device, the recording sheet after fixing is at a high temperature exceeding 100 ° C. Particularly in an image forming apparatus that processes at a high speed, when sheets are continuously fed, the recording sheets stacked on the sheet discharge tray are stored, and the toner fixed on the sheets is remelted, and the toner image is peeled off. In addition, there is a problem that a toner image adheres to the conveying means and causes a stain or scratch.
In order to solve such problems, there has been proposed a technique in which a cooling device is provided in the image forming apparatus and the sheet is cooled while being conveyed after thermal fixing (see, for example, Patent Documents 1 to 4).

In the technologies disclosed in Patent Documents 1 to 4, a cooling device is provided after heat fixing, and a heat pipe roller that cools the sheet while conveying the sheet within the image forming apparatus, and a heat pipe is provided in the conveyance guide. In each of these, a cooling device is provided after fixing, and a conveying roller and a heat pipe are provided in order to convey the sheet therein.
An image forming apparatus equipped with a thermal fixing device such as a copying machine or a printer is required to be small, high speed, and low cost. Also, image formation on both sides of a sheet is common for the purpose of saving sheets.
JP 60-186477 A Japanese Patent Laid-Open No. 62-104252 JP-A-4-260065 JP-A-4-104265

However, when the sheet on which image formation on one side has been completed is transported through the apparatus, the temperature in the apparatus further increases, and cooling by exhaust heat treatment with a conventional fan cannot keep up. For this reason, the number of fans increases, and there is a problem that the image forming apparatus must be increased in size.
Also, in a downsized image forming apparatus, water droplets adhere to the transport surface due to water vapor generated when the sheet passes through the thermal fixing device, and it adheres to the next transported sheet and forms a double-sided image. There is also a problem that transfer defects sometimes occur.

Therefore, the main object of the present invention is to cool the sheet after heat fixing in the downsized image forming apparatus in consideration of the above situation, and to lower the temperature of the sheet that has passed through the heat fixing apparatus. An object of the present invention is to provide an image forming apparatus in which the temperature of the double-sided path is lowered and the temperature rise of the entire apparatus is suppressed.
Another object of the present invention is to provide an image forming apparatus that eliminates the above-mentioned image defects by adopting a configuration in which water droplets are unlikely to adhere to a conveyance surface.

In order to solve the above problems, the invention according to claim 1, capable of forming a double-sided image, Te Tei with a heat fixing device, the conveying path for conveying the sheet on which the image is fixed by heat fixing device in images forming apparatus where the heat pipe is arranged as a cooling member, wherein the heat pipe is a cylindrical shape, a part of the periphery forms the plane of the conveying guide surface of the conveying path, the cylindrical The inside of the heat pipe is cooled by sucking or discharging air by a cooling fan disposed at the end of the heat pipe .
According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, a part of a plane as the conveyance guide surface is made of metal .
The invention of claim 3 is the image forming apparatus according to claim 2, wherein the metal is aluminum, and wherein the aluminum alloy, stainless steel, and brass.
The invention of claim 4 is the image forming apparatus according to claim 2 or 3, wherein said applying a Teflon coating on portions of the metal.

According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the conveyance speed of the conveyance drive roller downstream of the sheet conveyance is faster than the conveyance speed of the upstream conveyance drive roller. It is characterized by that.
According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the conveyance speed of the conveyance drive roller downstream of the sheet conveyance is slower than the conveyance speed of the upstream conveyance drive roller. It is characterized by that.

  According to the present invention, by lowering the temperature of the sheet that has passed through the thermal fixing device, the temperature of the double-sided path is also lowered, and the temperature rise of the entire image forming apparatus can be suppressed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic view showing a copying machine as an image forming apparatus. FIG. 2 is an enlarged schematic view showing the vicinity of the paper discharge unit from the thermal fixing device of the copying machine of FIG.
Referring to FIGS. 1 and 2, FIG. 1 shows an example in which a sheet fed from the right side on the paper surface is image-formed, thermally fixed, and discharged to the left discharge tray. In the copying machine 1 shown in FIG. 1, the sheet that has completed image formation and has passed through the heat fixing device 2 is guided to the conveyance guide plate 3 (FIG. 2) (conveyance path A), and is ejected by the ejection drive roller 4 to the ejection tray 5. Discharged to the top.
At this time, an image of only one side is given to the sheet. When images are formed on both sides of the sheet, the sheet that has passed through the thermal fixing device 2 is switched by the switching claw 6 moved to the position of the broken line, and is guided by the conveyance guide plate 9 to a conveyance path different from that on one side. Guided (conveyance path B).

The sheet conveyed by an appropriate amount by the switchback driving roller 7 rotating in the clockwise direction is switched back in the counterclockwise direction while being sandwiched between the switchback driving roller 7 and the switchback driven roller 8. It reverses by the driving roller 7.
The sheet conveyance path at this time is a conveyance path C. After that, the sheet guided by the transport driving rollers 10 and 12, the transport driven rollers 11 and 13, and the transport guide plate 9 and returned upstream from the image forming portion is provided with an image on the opposite surface. An image can be formed. Therefore, the switchback driving roller 7 and the switchback driven roller 8 do not need to rotate during the printing operation of only one side image.

The range through which the sheet on which image formation on one side is completed passes becomes high due to the influence of heat from this sheet. In the present invention, a cooling member (heat pipe) 14 is disposed in a double-sided conveyance path that passes when performing a double-sided image forming operation, and cooling is performed to suppress an increase in the temperature of the double-sided conveyance path and thus the entire copying machine. ing.
In general, the conveyance guide plates are often used as sheet guides by configuring a pair of plate-like members. Since it is plate-shaped, it is easy to receive heat, and therefore the temperature rises easily. In the present invention, the heat pipe 14 is arranged on the conveyance guide plate to cool the sheet on which the one-sided image formation is completed and the conveyance guide plate, thereby suppressing the temperature rise of the double-side conveyance path and thus the entire copying machine. is there.

FIG. 3 is a schematic cross-sectional view showing a heat pipe disposed on the conveyance guide plate. FIG. 4 is a schematic perspective view showing an example in which a cooling fan is arranged at the end of a hollow cylindrical heat pipe. FIG. 5 is a schematic perspective view showing an example in which a heat sink is arranged at the end of a heat pipe made of a material having good thermal conductivity. FIG. 6 is a schematic cross-sectional view showing a cylindrical conveyance guide plate.
In FIG. 3, a heat pipe 14 is disposed on the conveyance guide plate 9. In FIG. 4, the heat pipe 14 has a hollow cylindrical shape, and the cooling fan 16 is disposed at the end portion to suck or discharge air, thereby cooling the heat pipe 14, and consequently the conveyance guide plate 9. Can be cooled.

In FIG. 5, the heat pipe 14 is made of a material having good thermal conductivity, a heat sink 15 is disposed at the end, and the heat sink 15 is cooled by a cooling fan 16. Furthermore, as shown in FIG. 6, the conveyance guide plate 9 itself as a tubular shape, Ru can also be a heat pipe.
In this way, by lowering the temperature of the sheet that has passed through the thermal fixing device 2 (FIG. 2) by the conveyance guide plate 9 that contacts the sheet, the temperature of the double-sided conveyance paths B and C is also lowered, and the temperature of the entire image forming apparatus The rise can be suppressed.

The conveyance guide plate 9 on which the heat pipe 14 is arranged may be a conveyance guide plate on the side facing the sheet surface on which single-sided image formation has been completed or on the side opposite to the sheet surface on which single-sided image formation has been completed.
The conveyance guide plate 9 shown in FIGS. 3 to 6 is generally made of plastic. However, by making this with metal, the heat conductivity of the conveyance guide plate 9 is increased, and the cooling effect is further improved. Is also possible.
In this way, the temperature of the sheet that has passed through the thermal fixing device 2 can be lowered by the conveyance guide plate 9 that contacts the sheet. At this time, the conveyance guide plate 9 is made of metal, so that the sheet temperature is absorbed more efficiently than the plastic and the temperature of the double-sided conveyance path is lowered. it can.

FIG. 7 is a schematic view showing a transport guide plate made of plastic, a part of which is made of metal. However, if the entire conveying guide plate 9 is made of metal as described above, the weight of the parts and the degree of freedom of the shape are lost.
Therefore, as shown in FIG. 7, a part of the conveyance guide plate 9 made of plastic is constituted by a conveyance guide plate 17 made of metal, and the heat pipe 14 is attached to the metal conveyance guide plate 17 by an appropriate method.

By using only the portion of the transport guide plate 9 where the sheet comes into contact with the metal, the sheet temperature is absorbed more efficiently than with plastics, etc., and the temperature of the double-sided transport path is lowered, suppressing the overall temperature rise of the copier. can do. Compared with the case where the entire conveyance guide plate 9 is made of metal, the conveyance guide plate 9 can be reduced in weight, and the degree of freedom in shape can be increased.
In addition, by setting the metal portion as a portion where the sheet is easy to contact, even when water droplets due to water vapor adhere to the conveyance guide plate 9, it is possible to remove the water droplets before they grow large with the sheet. .

As the metal conveyance guide plate 17 described above, aluminum, an aluminum alloy, stainless steel, or brass can also be used. Since these metals have a higher thermal conductivity than ordinary iron-based metals, the cooling efficiency is further increased.
Thus, since aluminum, aluminum alloy, stainless steel, and brass have higher thermal conductivity than iron, heat can be absorbed from the sheet more efficiently. In addition, aluminum, aluminum alloy, stainless steel, and brass have high corrosion resistance against water vapor generated from the sheet that has passed through the heat fixing device 2 (FIG. 1), so that rust can be prevented.

  A Teflon (registered trademark) coating may be applied to the metal portion of the conveyance guide plate 9 or the surface in contact with the sheet. Even when the contact resistance between the metal and the sheet is somewhat generated, the sheet can be smoothly and smoothly conveyed by applying the Teflon (registered trademark) coating. Further, since the Teflon (registered trademark) coating is excellent in non-adhesiveness, the toner adheres to the conveyance guide plate 9 by applying the Teflon (registered trademark) coating to the surface facing the sheet surface on which the single-sided image formation is completed. Can also be prevented.

FIG. 8 is a schematic view showing a first method of fixing the conveyance guide plate and the heat pipe. FIG. 9 is a schematic view showing a second method of fixing the conveyance guide plate and the heat pipe. FIG. 10 is a schematic view showing a third method of fixing the conveyance guide plate and the heat pipe. FIG. 11 is a schematic view showing a fourth method of fixing the conveyance guide plate and the heat pipe. FIG. 12 is a schematic view showing a fifth method of fixing the conveyance guide plate and the heat pipe.
8 to 12 show several fixing methods of the conveyance guide plate 9 and the heat pipe 14. In order to cool the conveyance guide plate 9 in which the heat pipe 14 has become high temperature, it is necessary that the mutual contact is sufficiently made.

In the first method of FIG. 8, an elastic support member (plate spring) 20 is attached to the conveyance guide plate 9 by an appropriate method, and the heat pipe 14 is brought into contact with the conveyance guide plate 9 by the urging force of the plate spring 20. ing.
If the fixing member (not shown) is fixed, if a gap is generated between the fixing member and the heat pipe 14, the cooling efficiency of the conveyance guide plate 9 is reduced. However, if the leaf spring 20 has an urging force, the heat pipe 14 and the transport guide plate 9 can be mounted without gaps, so that the heat pipe 14 can efficiently absorb the heat of the transport guide plate 9.

In the second method of FIG. 9, the conveyance guide plate 9 and the heat pipe 14 are contact-fixed with an adhesive 21. In the third method of FIG. 10, the conveyance guide plate 9 and the heat pipe 14 are fixed in contact with a brazing material 22.
Although the adhesive 21 requires a little labor for the bonding operation, the contact area between the conveyance guide plate 9 and the heat pipe 14 is wide, so that the cooling efficiency is good. In the case of the brazing material 22, it is an effective means when the conveyance guide plate 9 is a metal.
As a means for increasing the contact area between the transport guide plate 9 and the heat pipe 14, the heat guide 14 is formed into a quadrangle as in the fourth method of FIG. 11, or the transport guide as in the fifth method of FIG. There is also a method of disposing the heat pipe 14 in the recess where the plate 9 is recessed. Of course, there is also a method of combining the method of FIGS. 8 to 10 and the method of FIGS.

FIG. 13 is a schematic perspective view showing a switchback drive roller having a heat pipe. FIG. 14 is a schematic cross-sectional view showing a configuration in which the heat pipe is directly a switchback drive roller.
FIG. 15 is a schematic cross-sectional view showing a configuration in which the heat pipe is mounted so that the switchback drive roller has a thick cylindrical shape and contacts the inner circle. FIG. 16 is a schematic cross-sectional view showing a configuration in which a heat pipe is mounted with a material having good heat conductivity such as silicon rubber near the center of a thin cylindrical switchback drive roller.

In FIG. 13, the heat sink 15 and the heat pipe 14 are attached to the switchback drive roller 7 (FIG. 2) by an appropriate method. In the configuration of FIG. 14, a configuration in which the heat pipe 14 directly becomes the switchback drive roller 7 is shown.
The configuration of FIG. 15 shows a configuration in which the heat pipe 14 is mounted so that the switchback drive roller 7 has a thick cylindrical shape and contacts the inner circle. In the configuration of FIG. 16, the switchback driving roller 7 has a thin cylindrical shape, and the heat pipe 14 is mounted near the center with a material 18 having good heat conductivity such as silicon rubber.
As described above, the cooling device 14 is disposed in the switchback driving roller 7 which is a conveyance roller, and the temperature of the sheet that has passed through the thermal fixing device is lowered by the conveyance roller. As a result, the temperature of the sheet is efficiently absorbed, the temperature of the double-sided conveyance path is lowered, and the temperature increase of the entire copying machine can be suppressed. In this case, the switchback drive roller 7 may be the switchback driven roller 8.

FIG. 17 is a schematic perspective view showing a switchback drive roller in which a rubber material is wound around a metal roller. FIG. 18 is a schematic perspective view showing a switchback drive roller in which a rubber material is wound around a part of a metal roller.
As a material most suitable for sheet conveyance, rubber having a large friction coefficient is generally used. This is because it is necessary to apply a large pressure between the driving roller and the driven roller in order to convey the sheet with the metal roller.
Therefore, in FIG. 17, the switchback drive roller 7 has a configuration in which a rubber material 26 is wound around a metal roller 25 having a constant diameter. In FIG. 18, the switchback drive roller 7 has a configuration in which a rubber material 26 is wound around a part of a metal roller 25 having a constant diameter. In this case, the switchback drive roller 7 may be the switchback driven roller 8 (FIG. 2).
In addition, a belt may be used to absorb more heat from the sheet. FIG. 19 is a schematic perspective view showing a belt 29 spanned between the switchback driving roller and the adjacent roller.

In FIG. 19, the belt 29 is hung on the switchback driving roller 7 and the conveying roller 27 adjacent to the switchback driving roller 7. Belt 29 is so time in contact with the sheet is long can absorb more heat, the sheet is Ru der cools by switchback drive roller 7 with a heat pipe (not shown).
The temperature of the sheet that has passed through the heat fixing device (FIG. 2) is lowered by the belt 29 that conveys the sheet and the metal conveying roller 7. By disposing the cooling device in the switchback driving roller 7 which is a conveying roller, the temperature of the sheet can be absorbed more efficiently, the temperature of the double-sided conveying path can be lowered, and the temperature increase of the entire copying machine can be suppressed.
Similarly, although not shown, it is also possible to place the belt 29 on the switchback driven roller 8 and the conveying roller 28 adjacent to the switchback driven roller 8 and arrange a heat pipe on the switchback driven roller 8. is there.

FIG. 20 is a schematic diagram showing a state of a sheet between a certain conveyance driving roller and the next conveyance driving roller in a first state. FIG. 21 is a schematic diagram showing a state of a sheet between a certain conveyance driving roller and the next conveyance driving roller in a second state. FIG. 22 is a schematic diagram illustrating a third state of a sheet between a certain conveyance driving roller and the next conveyance driving roller.
Referring to FIG. 20 to FIG. 22, the sheet feeding speed of a certain conveyance driving roller (in this case, the switchback driving roller 7 in FIG. 2) is V1, and then the conveyance driving roller to which the sheet P reaches (this In this case, when the sheet feeding speed of the conveyance driving roller 10 in FIG. 2 is V2, the relation of V1 <V2 is established.

The two transport driving rollers described above may be the fixing roller and the switchback driving roller 7 of the heat fixing apparatus 2 in FIG. 2 as well as the above case, and may be the transport driving roller 10 and the transport driving roller 12 in the same manner. . In such a setting, the sheet P receives a pulling force in the downstream direction (FIGS. 20 to 22).
If the conveyance guide plate 9 between the two conveyance drive rollers 7 and 10 is slightly bent, the sheet P is rubbed against the conveyance guide plate 9. At this time, if the heat pipe 14 is provided on the conveyance guide plate 9, the heat of the sheet P can be more efficiently transferred to the heat pipe 14.

The sheet P is rubbed against the conveyance guide plate 9 by the sheet P being pulled by the downstream conveyance drive roller 10. As described above, in this case, if the heat pipe 14 is provided on the conveyance guide plate 9, the heat of the sheet P can be cooled more efficiently. Further, water droplets generated at the portion where the sheet P and the conveyance guide plate 9 are rubbed can be removed by the sheet P before they grow large.
Conversely, although not shown, when the paper feed speed of a certain transport drive roller is V1, and the transport speed of the transport drive roller that the sheet reaches next is V2, the relationship of V1> V2 is established. In this case, the sheet receives a force in the direction of sagging. 20 to 22, the same effect can be obtained by providing a heat pipe on the opposite conveyance guide plate.
When the upstream conveyance driving roller presses the sheet, the sheet is deflected and pressed against the conveyance guide plate. If the transport guide plate is provided with a heat pipe, the heat of the paper can be cooled more efficiently. Furthermore, water droplets generated at the portion where the sheet and the conveyance guide plate are pressed can be removed by the sheet before it grows greatly.

A heat pipe is used as the heat pipe 14 described above. Since the heat pipe has a small cross-sectional area and a degree of freedom in shape, it can be arranged in a narrow portion. As a result, the copying machine can be further downsized.
Each of the above-described configurations may be used alone or in combination. The location and number of use are greatly influenced by design convenience, but should be optimally arranged depending on conditions such as the number of sheets processed by the copier, which is an image forming apparatus, the temperature of the heat fixing device, and the conveyance path after the heat fixing device. is there.

FIG. 23 is a schematic explanatory diagram illustrating a printer including a thermal fixing device that conveys a sheet from the lower side to the upper side in the vertical direction. FIG. 24 is an enlarged schematic view showing the sheet conveyance path and the vicinity of the heat fixing device of the printer of FIG.
In the printer 31 of FIGS. 23 and 24, the sheet feeding unit including the sheet feeding cassette and the image forming unit including the writing optical system are not directly related to the present invention, so that the registration roller 32, the secondary transfer roller 33, and The description other than the intermediate transfer belt 34 is omitted.
A sheet (not shown) that has finished forming an image with the secondary transfer roller 33 and the intermediate transfer belt 34 and has passed through the heat fixing device 2 is guided by the conveyance guide plate 3 (conveyance path A), and the discharge drive roller 4. Is discharged onto the paper discharge tray 5. At this time, an image of only one side is given to the sheet.

When images are formed on both sides of the sheet, the sheet that has passed through the thermal fixing device 2 is switched to the conveyance path by the switching claw 6 that has moved to the position of the broken line, and is guided to a conveyance path (conveyance path B) that is different from that on one side. The
The sheet conveyed by an appropriate amount by the switchback driving roller 7 rotating in the clockwise direction is switched back in the counterclockwise direction while being sandwiched between the switchback driving roller 7 and the switchback driven roller 8. It reverses by the driving roller 7.
The sheet conveyance path at this time becomes the conveyance path C by the switching claw 6 that has returned to the solid line position. Thereafter, the sheet is guided by the conveyance drive rollers 10 and 12, the conveyance driven rollers 11 and 13, and the conveyance guide plate 9 and returned upstream from the image forming portion. In this way, by providing an image on the opposite surface, it is possible to form an image on both surfaces. Therefore, the switchback driving roller 7 and the switchback driven roller 8 do not need to rotate during the printing operation of only one side image.

Since the heat fixing device 2 is at a high temperature, its upstream side is also at a high temperature. In addition, the upstream side and the conveyance path range through which the sheet on which image formation on one side is completed pass are also heated due to the heat from the sheet.
Therefore, in the copying machine shown in FIGS. 23 and 24, for example, the switchback drive roller 7 is changed to the switchback drive roller 7 shown in FIG. 14, and in the conveyance path between the conveyance drive roller 10 and the conveyance drive roller 12. A heat pipe 14 is arranged on the transport guide plate 9 by an appropriate method.
As described above, according to the present invention, cooling is performed by providing the heat pipe 14 in the double-sided conveyance path that passes when the double-sided image forming operation is performed, and the temperature increase of the double-sided conveyance path, that is, the entire apparatus is suppressed. I am doing so.

1 is a schematic diagram showing a copier that is an image forming apparatus. FIG. 2 is a schematic diagram showing an enlargement of the vicinity of a paper discharge unit from the thermal fixing device of the copying machine of FIG. 1. The schematic sectional drawing which shows the heat pipe arrange | positioned on a conveyance guide plate. The schematic perspective view which shows the example which has arrange | positioned the cooling fan in the edge part of a hollow cylindrical heat pipe. The schematic perspective view which shows the example which has arrange | positioned the heat sink to the edge part of the heat pipe which consists of material with good heat conductivity. The schematic sectional drawing which shows a cylindrical conveyance guide plate. Schematic which shows the conveyance guide plate which consists of a plastic partially comprised with the metal. Schematic which shows the 1st method of fixation with a conveyance guide plate and a heat pipe. Schematic which shows the 2nd method of fixation with a conveyance guide plate and a heat pipe. Schematic which shows the 3rd method of fixation with a conveyance guide plate and a heat pipe. Schematic which shows the 4th method of fixation with a conveyance guide plate and a heat pipe. Schematic which shows the 5th method of fixation with a conveyance guide plate and a heat pipe. The schematic perspective view which shows the switchback drive roller provided with the heat pipe. The schematic sectional drawing which shows the structure from which a heat pipe becomes a switchback drive roller directly. The schematic sectional drawing which shows the structure which mounts a heat pipe so that a switchback drive roller may contact the inner circle | round | yen with the thickness cylindrical. FIG. 3 is a schematic cross-sectional view showing a configuration in which a heat pipe is mounted with a material having good heat conductivity such as silicon rubber near the center of a thin cylindrical switchback drive roller. The schematic perspective view which shows the switchback drive roller by which the rubber material was wound around the metal roller. The schematic perspective view which shows the switchback drive roller by which the rubber material was wound around a part of metal roller. The schematic perspective view which shows the belt spanned between the switchback drive roller and the adjacent roller. Schematic which shows the state of the sheet | seat between a certain conveyance drive roller and the following conveyance drive roller in a 1st state. Schematic which shows the state of the sheet | seat between a certain conveyance drive roller and the following conveyance drive roller in a 2nd state. Schematic which shows the state of the sheet | seat between a certain conveyance drive roller and the following conveyance drive roller in a 3rd state. FIG. 3 is a schematic explanatory diagram illustrating a printer including a thermal fixing device that conveys a sheet from the lower side to the upper side in the vertical direction. FIG. 24 is a schematic diagram showing an enlarged view of the sheet conveyance path and the vicinity of the thermal fixing device of the printer of FIG. 23.

Explanation of symbols

1 Copying machine (image forming device)
2 thermal fixing device 3 transport guide plate 4 discharge roller 6 switching claw 7 switchback transport drive roller 8 switchback transport driven roller 9 transport guide plate 10 transport roller (drive roller)
11 Conveying roller (driven roller)
12 Conveyance roller (drive roller)
13 Conveyor roller (driven roller)
14 Cooling member (heat pipe)
17 Metal part 20 of conveyance guide plate 20 Plate spring 21 Adhesive material 22 Brazing 25 Metal roller 26 Rubber material 27 Conveyance roller 28 Conveyance roller 29 Belt 31 Printer (image forming apparatus)
A Transport route B Transport route C Transport route P Sheet

Claims (6)

Sided image forms Te Tei with a heat fixing device, in images forming apparatus where the heat pipe is arranged as a cooling member in the conveying path for conveying the sheet on which the image is fixed by heat fixing device,
The heat pipe has a cylindrical shape, and a part of its outer periphery forms a flat surface as a conveyance guide surface of the double-sided conveyance path, and the inside of the cylindrical heat pipe is cooled at the end of the heat pipe. An image forming apparatus , wherein air is sucked or discharged by a fan to be cooled . The image forming apparatus according to claim 1, wherein the plane portion as the conveyance guide surface is made of metal . The metals include aluminum, aluminum alloy, stainless steel, an image forming apparatus according to claim 2, characterized in that the brass. The image forming apparatus according to claim 2 or 3, wherein applying a Teflon coating on portions of the metal. 5. The image forming apparatus according to claim 1, wherein a conveyance speed by a conveyance driving roller downstream of sheet conveyance is faster than a conveyance speed of an upstream conveyance driving roller . 5. The image forming apparatus according to claim 1, wherein the conveyance speed of the conveyance drive roller downstream of the sheet conveyance is lower than the conveyance speed of the upstream conveyance drive roller .

Images