JP7238419B2 - Conveying device and image forming device - Google Patents

Description

The present invention relates to a conveying device and an image forming apparatus.

Conventionally, there has been known a conveying apparatus including a conveying roller having a roller portion that contacts and conveys a sheet that has passed through a heating means, a roller shaft that supports the roller portion, and means for releasing heat from the roller portion.

In Patent Document 1, as a means for radiating heat from the roller portion, the conveying roller is composed of a heat pipe, and a cylindrical heat radiating portion having a larger diameter than the roller shaft is provided at the axial end of the conveying roller. It is described that the heat of the roller portion of the roller is dissipated by the heat radiating portion so that the heat of the roller portion is released.

However, in Patent Document 1, there is a problem that it leads to an increase in the size of the device and an increase in the cost of the device.

In order to solve the above-described problems, the present invention provides a conveying roller having a roller portion that contacts and conveys a sheet that has passed through heating means, and a roller shaft that supports the roller portion, and heat from the roller portion. The means for releasing the heat of the roller portion is a thermally conductive member having one end in contact with the roller shaft, and the roller portion is made of a rubber material and is axially , are provided at predetermined intervals, and one end of the heat-conducting member is brought into contact between the roller portions of the roller shaft.

According to the present invention, it is possible to release the heat of the roller portion while avoiding an increase in the size of the apparatus.

1 is a schematic configuration diagram of an image forming apparatus according to the present embodiment; FIG. FIG. 4 is a schematic perspective view showing a paper ejection drive roller and a heat radiating member as a thermally conductive member; FIG. 4 is a schematic cross-sectional view of a paper discharge drive roller; 1 is a schematic perspective view showing a part of a housing of an image forming apparatus, a fixing device, a document reading section, a pair of discharge rollers, and a heat radiating member; FIG. The schematic perspective view of a housing|casing. The schematic perspective view of the modification 1. FIG. The schematic perspective view of the modification 2. FIG. The figure which shows the example which caulked-fixed the thermal radiation part to the bearing part. FIG. 11 is a diagram showing an example in which the heat radiating member of Modification 2 is brought into contact between the roller portions of the roller shaft; It is a schematic configuration diagram in which a bearing portion is a slide bearing. The schematic perspective view of the modification 3. FIG. The schematic perspective view of the modification 4. FIG. FIG. 10 is a view showing an example in which the heat of the roller portion of the discharge driven roller is released by a heat radiating member;

An embodiment in which a developing device according to the present invention is applied to an intermediate transfer type tandem-type full-color image forming apparatus (hereinafter simply referred to as "image forming apparatus") will be described below.
FIG. 1 is a schematic configuration diagram of an image forming apparatus 1 according to this embodiment. An outline of the image forming apparatus 1 will be described with reference to FIG. The image forming apparatus 1 includes an automatic document feeder 3 and a document reading section 4 in this order from the top of the main body. Below the document reading section 4, there is provided a stack section 5 for stacking recording paper P as a recording medium on which an image has been formed. An image forming section 2 for forming an image based on a document image read by the document reading section 4 and a paper feeding section 6 for feeding recording paper P to the image forming section 2 are provided below the stack section 5 . there is

The automatic document feeder 3 separates the originals one by one from the bundle of originals and automatically feeds them onto the contact glass of the original reading unit 4, and the originals fed onto the contact glass are read by the original reading unit 4. FIG.

The image forming section 2 includes an intermediate transfer belt 17 that is stretched around a plurality of support rollers and that moves counterclockwise in the figure. Image forming units 10Y, 10C, and 10M for forming toner images of yellow (Y), cyan (C), magenta (M), and black (K) on the lower stretched surface of the intermediate transfer belt 17. , 10K are arranged in parallel. Each of the image forming units 10Y, 10C, 10M, and 10K includes photoreceptors 11Y, 11C, 11M, and 11K on which toner images of respective colors are formed. A charging device, developing devices 13Y, 13C, 13M and 13K, a photoconductor cleaning device and the like are provided around the photoconductors 11Y, 11C, 11M and 11K, respectively.

Primary transfer rollers 14Y, 14C, 14M, and 14K are provided so as to come into contact with the inner peripheral surfaces of the intermediate transfer belt 17 at positions facing the photoreceptors 11Y, 11C, 11M, and 11K. Further, a secondary transfer roller 18 is provided so as to contact the outer peripheral surface of the intermediate transfer belt 17 downstream of the primary transfer rollers 14Y, 14C, 14M, and 14K with respect to the surface movement direction. Further, a belt cleaning device is provided so as to come into contact with the outer peripheral surface of the intermediate transfer belt 17 on the downstream side of the secondary transfer roller 18 . A fixing device 20 is provided above the secondary transfer roller 18 . The fixing device 20 includes a heat source-incorporating fixing roller 20a and a pressure roller 20b that presses against the fixing roller 20a.

Below the image forming units 10Y, 10C, 10M and 10K, an optical writing unit 19 is provided for irradiating the photoreceptors 11Y, 11C, 11M and 11K with laser light. A toner supply device 30 is provided above the intermediate transfer belt 17 . Four toner cartridges (toner containers) corresponding to respective colors (yellow, cyan, magenta, and black) are detachably (exchangeably) installed in the toner replenishing device 30 . A part other than the toner cartridge in the toner replenishing device 30 is a toner conveying device that conveys the toner discharged from the toner cartridge to the developing devices 13Y, 13C, 13M, and 13K.

The paper feed unit 6 has a paper feed cassette 7 containing a plurality of stacked recording papers P, and directs the topmost recording paper P from the multiple stacked recording papers P to the image forming unit 2 . and a paper feed roller 8 for feeding paper.

An image forming operation of the image forming apparatus 1 having the above configuration will be described.
Each image forming unit 10 forms a toner image of each color. As each photoreceptor 11 rotates, the charging device first uniformly charges the surface of the photoreceptor 11 . Next, the optical writing unit 19 irradiates each photoreceptor 11 with laser light based on image information data obtained by separating the image data of the document read by the document reading unit 4 into each color, thereby forming an electrostatic latent image. . After that, each developing device 13 attaches toner to the electrostatic latent image to visualize it, thereby forming a toner image of each color on each photosensitive member 11 .

The respective color toner images on the photoreceptors 11Y, 11C, 11M and 11K are sequentially transferred onto the intermediate transfer belt 17 by the primary transfer rollers 14Y, 14C, 14M and 14K to form superimposed color toner images. Residual toner is removed from the surfaces of the photoreceptors 11Y, 11C, 11M, and 11K after the transfer of the toner images by the photoreceptor cleaning devices 15Y, 15C, 15M, and 15K to prepare for the next image formation.

On the other hand, in the paper feeding section 6, the recording paper P accommodated in the paper feeding cassette 7 is separated one by one, sent out toward the image forming section 2 by the paper feeding roller 8, and stopped by being abutted against the registration roller 9. Then, the recording paper P hit and stopped by the registration roller 9 is fed to the secondary transfer portion between the intermediate transfer belt 17 and the secondary transfer roller 18 in accordance with the timing of toner image formation in the image forming portion 2 . At the secondary transfer portion, the superimposed color toner image on the intermediate transfer belt 17 is transferred onto the supplied recording paper P. FIG.

The recording paper P onto which the toner image has been transferred is sent to a fixing device 20 as heating means. The fixing device 20 heats and presses the fed recording paper P by sandwiching it between a fixing nip formed by contact between a fixing roller 20a containing a heat source and a pressure roller 20b pressed toward the fixing roller 20a. By this action, the toner of the full-color image on the recording paper P is softened and fixed on the surface of the recording paper P. As shown in FIG. After that, the recording paper P is discharged to the stack section 5 by a paper discharge roller pair 26 consisting of a paper discharge drive roller 21 and a paper discharge driven roller 25 . On the other hand, after the transfer of the toner image, the surface of the intermediate transfer belt 17 is cleaned by removing residual toner by a belt cleaning device to prepare for the next image formation.

In this embodiment, each image forming unit 10 is supported on a common support for the photoreceptor 11, the charging device, the developing device 13, and the photoreceptor cleaning device, and can be attached to and detached from the main body of the printer integrally. It takes the form of a process cartridge composed of By adopting such a process cartridge form, maintainability can be improved.

The recording paper P that has passed through the fixing device 20 is heated by the fixing device 20 to raise its temperature. Therefore, the heat is transferred from the recording paper P whose temperature has risen to the discharge roller that conveys the recording paper P that has passed through the fixing device 20 . When the number of sheets continuously passed is large, the temperature of the discharge roller continues to rise, and the toner on the fixed image surface of the recording sheet is partially remelted, which may cause image effects such as roller marks.

Conventionally, there is a roller portion configured with a heat pipe to quickly transfer heat between the roller portion and a heat radiating portion provided at the axial end of the conveying roller, thereby suppressing the temperature rise of the roller portion. , which may lead to an increase in the cost of the apparatus.

Therefore, in the present embodiment, the heat of the roller portion is released by a simple structure in which a heat radiating member as a thermally conductive member is brought into contact with the roller shaft of the discharge roller. Characteristic portions of the image forming apparatus will be specifically described below.

FIG. 2 is a schematic perspective view showing the paper ejection driving roller 21 and the heat radiating member 22 as a heat conductive member.
As shown in FIG. 2, the paper ejection drive roller 21, which contacts the image on the recording paper immediately after fixing, has a roller portion 21a made of rubber and a roller shaft 21b made of metal with a predetermined interval in the vicinity of the center of the roller shaft 21b. There are two One end of a plate-shaped heat radiating member 22 made of a highly thermally conductive member is in contact with the outer diameter surface of the roller shaft 21b. The heat transferred from the recording paper P to the surface of the roller portion 21 a is transferred to the heat dissipation member 22 via the roller shaft 21 b and is radiated by the heat dissipation member 22 . In this way, with a simple structure in which the plate-shaped heat radiating member 22 is brought into contact with the roller shaft 21b, the heat of the roller portion 21a can be dissipated through the roller shaft 21b. The cost of the device can be reduced compared to the one in which the heat of the roller portion is transferred to the heat radiating portion provided at the end of the shaft of the discharge driving roller 21 to release the heat of the roller portion. Moreover, the heat radiating member 22 can be brought into contact with an appropriate portion of the roller shaft, and the heat radiating member 22 can be crawled around in an empty space of the device. It is possible to suppress

In addition, by bringing the heat radiating member 22 into contact with the outer diameter surface of the roller shaft 21b, the heat radiating member can be dissipated from the roller portion 21a as compared with the case where the heat radiating member is brought into contact with the shaft end portion of the roller shaft 21b. The heat transfer distance to can be shortened. Thereby, the heat of the roller portion 21a can be quickly transferred to the heat radiating member 22 via the roller shaft 21b, and the heat can be radiated by the heat radiating member 22. FIG. As a result, it is possible to satisfactorily suppress the temperature rise of the roller portion and the roller shaft, and it is possible to suppress the remelting of a part of the toner on the image surface of the recording paper P, and the formation of roller marks on the image. It is possible to suppress image deterioration such as

In addition, by bringing the heat radiating member 22 into contact with the outer diameter surface of the roller shaft 21b, the heat transfer distance from each roller portion 21a to the heat radiating member 22 can be substantially equalized, and both roller portions 21a can be substantially dissipated. Heat can be evenly transferred to the heat radiating member, and the temperature of the plurality of roller portions 21a can be evenly lowered.

FIG. 3 is a schematic cross-sectional view of the paper discharge driving roller 21. As shown in FIG.
The diameter φd of the roller shaft 21b of the paper discharge roller portion of the paper discharge driving roller 21 is set to 10 mm or more, preferably as large as possible. By increasing the diameter φd of the roller shaft, the contact area with the roller portion 21a can be increased, and the heat transfer efficiency from the roller portion 21a to the roller shaft 21b can be increased, which is preferable. Furthermore, by increasing the diameter φd of the roller shaft 21b, the heat capacity of the roller shaft 21b can be increased, and the temperature rise of the roller shaft 21b can be suppressed. As a result, it is possible to suppress the deterioration of the heat conduction efficiency from the roller portion 21a to the roller shaft 21b, and it is possible to suppress the temperature rise of the roller portion 21a, which is preferable.

Further, it is preferable to set the diameter φD of the roller portion 21a as small as possible and the thickness of the roller portion 21a to 8 mm or less (φD≦φd+8). The roller portion 21a is made of a rubber material, and has a lower thermal conductivity than metal, making it difficult for heat to move. Therefore, by setting the thickness of the roller portion 21a to 8 mm or less and making it as thin as possible, the heat of the recording paper P that has moved to the surface of the roller portion 21a can be quickly transferred to the roller shaft 21b, and the temperature of the roller portion 21a rises. can be suppressed, which is preferable.

Further, by forming the roller portion 21a from a rubber material, the roller portion 21a is elastically deformed when the discharge driven roller 25 comes into contact with the roller portion 21a to form a predetermined nip width. By having a predetermined nip width in this manner, a high conveying force can be maintained. Further, by having a predetermined nip width, the pressure from the roller portion applied to the image on the recording paper P is reduced. As a result, it is possible to prevent roller marks from being generated on the image.

FIG. 4 is a schematic perspective view showing part of the housing 40 of the image forming apparatus, the fixing device 20, the document reading section 4, the pair of discharge rollers, and the heat dissipation member 22. As shown in FIG.
As shown in FIG. 4, the other end of the heat radiating member 22 is screwed to a scanner bracket 46 as a scanner support member for supporting the document reading section 4 made of metal and screwed to the housing 40 . By connecting the heat radiation member 22 to the metal member of the housing 40 in this manner, the heat of the roller portion 21a that has moved to the heat radiation member 22 can be transferred to the scanner bracket 46, and the heat is also radiated from the scanner bracket 46. be able to.

FIG. 5 is a schematic perspective view of the housing.
The housing 40 includes a bottom plate 47, support stays 41 and 42 erected at both left and right ends on the front side of the image forming apparatus, and arranged on the back side of the image forming apparatus to support images such as a photoreceptor, a developing roller, and a conveying roller. A side plate 43 is provided for holding a driving device or the like for rotating a rotating body provided in the forming device. It also has front beam stays 45a, 45b extending in the left-right direction screwed to the two support stays 41, 42, and a plurality of front and rear beam stays 44a, 44b, 44c, 44d, 44e extending in the front-rear direction. there is

Each member (pillar stays 41, 42, side plate 43, front side beam stays 45a, 45b, front and rear beam stays 44a, 44b, 44c, 44d, 44e, bottom plate 47) constituting the housing 40 is made of metal. ing. Therefore, by screwing the other end of the heat radiating member 22 to the scanner bracket 46 that is screwed to the housing 40 , it can be moved from the scanner bracket 46 to the housing 40 . The heat of the roller portion can be dissipated through the entire housing 40 . In addition, by connecting the heat dissipation member 22 to the housing 40 having a large heat capacity, the temperature rise of the heat dissipation member 22 can be suppressed, and even if a large number of sheets are continuously passed, the temperature rise of the heat dissipation member 22 can be suppressed. The heat of the roller portion can be transferred to the heat radiating member 22 satisfactorily.

In the present embodiment, the heat dissipation member 22 is connected to the housing 40, but any component made of metal and having a large heat capacity may be used. It may be connected to the housing of the document reading section 4 or the housing of the automatic document feeder 3 as a member.

Next, a modified example will be described.
[Modification 1]
FIG. 6 is a schematic perspective view of Modification 1. FIG.
As shown in FIG. 6, in this modified example 1, a plurality of heat radiating members 22 are brought into contact with the outer diameter surface of the roller shaft 21b. By bringing the plurality of heat radiating members 22 into contact with the outer diameter surface of the roller shaft 21b in this way, the heat transfer efficiency from the roller shaft to the heat radiating member can be increased, and the temperature rise of the roller portion 21a can be suppressed. can.

Of the two heat dissipating members, the other end of the heat dissipating member 22 arranged on the back side of the apparatus is fastened to the scanner bracket 46 shown in FIG. 4 arranged in the portion surrounded by A of the housing 40 shown in FIG. The other end of the heat dissipating member 22 arranged in front of the apparatus is fastened to the portion surrounded by A of the housing 40 shown in FIG.

In addition, a plurality of abutment portions that contact the roller shaft are provided on one heat radiating member 22 at predetermined intervals in the axial direction so that heat can be transferred to the heat radiating member 22 at a plurality of locations in the axial direction of the roller shaft. can be Even with such a configuration, the heat transfer efficiency from the roller shaft 21b to the heat radiating member 22 can be enhanced.

[Modification 2]
FIG. 7 is a schematic perspective view of Modification 2. FIG.
In this modified example 2, the heat radiating member 22 is brought into contact with the roller shaft 21b via a bearing member 27 that rotatably supports the roller shaft 21b.
In Modification 2, the heat radiating member 22 is composed of a heat radiating portion 22b and a bearing portion 22a. Since the discharge driving roller 21 is rotationally driven, in the configuration shown in FIGS. 2 and 6, the heat radiating member 22 slides on the roller shaft 21b, which may generate sliding noise. On the other hand, in Modification 2, since the heat radiating member 22 has the bearing portion 22a, it is possible to prevent the generation of sliding noise between the heat radiating member 22 and the roller shaft 21b. Moreover, the contact area between the roller shaft 21b and the heat radiating member 22 can be increased, and the heat transfer efficiency from the roller shaft 21b to the heat radiating member 22 can be increased.

The heat radiating portion 22b is a plate-like member that curves outward in the axial direction and has a plate spring portion 122 that is elastically deformable in the axial direction. A through hole 123 is provided through which a fitting portion 121 that fits into the fitting hole portion 49a that fits into the fitting hole 49a of 49 penetrates. The bearing portion 22a is a rolling bearing made of metal such as a ball bearing.

The fitting portion 121 of the bearing portion 22a is passed through the fitting hole portion 49a of the heat radiating portion 22b, and the fitting portion 121 is fitted into the fitting hole 49a of the side plate 49 of the device. At the time of fitting, the plate spring portion 122 of the heat radiating portion 22b is pressed toward the device side plate 49 by the bearing portion 22a to elastically deform the plate spring portion 122, thereby bringing the heat radiating portion 22b into contact with the bearing portion 22a. Thus, the bearing portion 22a and the heat radiating portion 22b are thermally connected. As a result, the heat of the roller portion 21 a can be conducted from the roller shaft 21 b to the heat radiating portion 22 b via the bearing portion 22 a and radiated by the heat radiating portion 22 .

Alternatively, as shown in FIG. 8, the heat radiating portion 22b may be fixed to the bearing portion 22a by caulking or the like. Further, as shown in FIG. 9, a heat radiating member 22 composed of a heat radiating portion 22b and a bearing portion 22a may be provided between the roller portions.

Moreover, as shown in FIG. 10, the bearing portion 22a may be a slide bearing in which grease G is enclosed. The grease G can improve the adhesion between the roller shaft 21b and the bearing portion 22a, can improve the heat transfer efficiency from the roller shaft 21b to the heat radiating member 22, and can suppress the temperature rise of the roller portion 21a.

[Modification 3]
FIG. 11 is a schematic perspective view of Modification 3. FIG.
In Modification 3, the roller shaft 21b of the discharge driving roller 21 is made of carbon graphite. In this modified example 3, except for the portion where the roller portion 21a is inserted and the axial end portion where the bearing portion 22a of the heat radiating member 22 is inserted, the cross section is used to reduce the weight. Also, as with the metal shaft, the cross section may be circular to increase the heat transfer efficiency as the cross section becomes larger than the cross section. Further, in this modified example 3, a part of the outer peripheral surface of the bearing portion 22a has a mounting surface 124 to which the planar heat radiating portion 22b is mounted. It is

Carbon graphite has a thermal conductivity about 2 to 5 times that of copper, which has a relatively high thermal conductivity among metals. 21b, the heat can be quickly conducted to the heat radiating member 22, and the temperature rise of the roller portion 21a can be suppressed.

Further, the heat dissipation member 22 having the bearing portion 22a and the heat dissipation portion 22b may be made of carbon graphite. By configuring the heat radiating member 22 with carbon graphite, the heat of the roller portion 21a can be quickly radiated. In addition, by forming the heat radiating member 22 from carbon graphite, it can be formed by a mold or the like.

[Modification 4]
12 is a schematic perspective view of Modification 4. FIG.
In this modification 4, an air-cooling portion 22c having a plurality of fins 122c is provided at the other end of the heat radiating member 22, and the air-cooling portion 22c is air-cooled by the fan 100 provided in the housing 40. be. By air-cooling the heat radiating member 22 in this manner, the heat radiation effect can be enhanced, and the temperature rise of the roller portion 21a can be suppressed. Further, by providing a plurality of fins 122c in the air-cooled portion of the heat radiating member 22 which is hit by the air sent from the fan 100 and increasing the surface area, efficient air-cooling can be achieved.

Since the fan 100 is generally provided to cool another unit of the image forming apparatus, the heat dissipation member 22 is appropriately arranged (sprawled) to prevent the air from the fan 100 in the apparatus from being cooled. By providing the air cooling section 22c in the air blowing path, it is possible to dissipate heat without adding a new fan. In FIG. 12, one end of the heat radiating member 22 is in contact with the roller shaft located outside the device side plate 49, but one end of the heat radiating member 22 is in contact with the inner side of the device side plate 49 of the roller shaft 21b. You may contact.

Alternatively, a heat radiating member may be brought into contact with the outer diameter surface of the roller shaft of the paper discharge driven roller 25 so that the heat of the roller portion of the paper discharge driven roller 25 can be released by the heat radiating member.
FIG. 13 is a diagram showing an example in which the heat of the roller portion of the discharge follower roller 25 is dissipated by a heat radiating member.
In the example shown in FIG. 13, the driven roller portion 25a of the discharge driven roller 25 is rotatably supported on the driven roller shaft 25b. The driven heat radiating member 28 is brought into contact therewith. In FIG. 13, the driven roller shaft 25b does not rotate together with the driven roller portion 25a, so no sliding noise is generated between the driven heat radiating member 28 and the driven roller shaft 25b.

In the configuration in which the driven roller shaft 25b rotates integrally with the driven roller portion 25a, the driven heat radiating member and the driven roller shaft 25b are provided with bearing portions as in the second modification. It is possible to prevent the occurrence of sliding noise between them. However, as shown in FIG. 13, the driven roller portion 25a is rotatably supported on the driven roller shaft 25b, and the driven roller shaft does not rotate. This eliminates the need to provide it, which is preferable because the configuration can be simplified.

The temperature of the discharge driven roller 25 also rises due to the transfer of heat from the recording paper P. As shown in FIG. Therefore, during double-sided printing, if the image formed on the first side of the recording paper comes into contact with the high-temperature discharge driven roller 25, part of the toner on the surface of the image is remelted and the image is removed from the driven roller portion. Roller traces of 25a may occur. Therefore, for the discharge driven roller 25 as well, the driven roller portion 25a is dissipated by bringing the driven heat radiating member 28 into contact with the outer diameter surface of the driven roller shaft 25b to radiate the heat of the driven roller portion 25a. Temperature rise can be suppressed. As a result, it is possible to suppress the occurrence of roller marks on the image formed on the first surface during double-sided printing.

What has been described above is only an example, and each of the following aspects has a unique effect.
(Aspect 1)
Conveying rollers such as a discharge drive roller 21 having a roller portion 21a that contacts and conveys a sheet that has passed through a heating means such as the fixing device 20, and a roller shaft 21b that supports the roller portion 21a, and heat from the roller portion is released. means, the means for releasing heat from the roller portion 21a is a thermally conductive member such as a heat radiating member 22 having one end in contact with the roller shaft 21b.
According to this, the heat of the roller portion 21a can be released to the heat conductive member via the roller shaft 21b with a simple structure in which one end of the heat conductive member such as the heat radiating member 22 is brought into contact with the roller shaft 21b. can be done. In addition, the other end of the thermally conductive member can be laid around in an empty space inside the apparatus as appropriate, thereby suppressing an increase in the size of the apparatus. As a means for radiating the heat of the roller portion 21a, the transport rollers such as the discharge drive roller 21 are formed of heat pipes, and the heat dissipation portion is provided at the end of the shaft. It is possible to suppress the increase in size and the cost of the device.

(Aspect 2)
In aspect 1, the roller portion 21a is made of a rubber material, and is provided in plurality at predetermined intervals in the axial direction. abutted in between.
According to this, the heat transfer distance from one of the two roller portions to the heat-dissipating member 22 and the heat transfer distance from the other roller portion to the heat-conducting member are the same. and heat can be evenly transferred from both rubber roller portions to the thermally conductive member. Thereby, it is possible to suppress the occurrence of a temperature difference between the plurality of rubber roller portions.

(Aspect 3)
In mode 1 or 2, the other end of the thermally conductive member such as the heat radiating member 22 is thermally connected to the housing of the main unit on which the transfer device is mounted or to a member outside the main unit.
According to this, as described in the embodiment, the heat of the roller portion 21a of the conveying roller can be radiated from the housing of the main unit or a member outside the main unit, thereby suppressing the temperature rise of the roller portion. can do. Further, by thermally connecting a thermally conductive member such as the heat radiating member 22 to the housing of the main unit or a member outside the main unit, the heat capacity can be increased and the temperature rise of the heat radiating member can be suppressed. Therefore, even if the number of sheets continuously passed is large, the heat of the roller portion can be favorably transferred to the heat radiating member, and the temperature rise of the roller portion can be suppressed.

(Aspect 4)
In any one of Modes 1 to 3, the diameter of the roller shaft 21b is 10 mm or more, and D=d+8 mm or less, where D is the diameter of the roller portion 21a and d is the diameter of the roller shaft.
According to this, as described in the embodiment, by setting the diameter of the roller shaft 21b to 10 mm or more, the heat capacity of the roller shaft 21b can be increased, and the heat capacity of the roller shaft 21b can be increased when heat is transferred from the roller portion 21a. 21b can be suppressed. Also, the contact area between the roller portion 21a and the roller shaft 21b can be increased. Thereby, the heat transfer efficiency from the roller portion 21a to the roller shaft 21b can be enhanced.
Further, when the diameter of the roller portion 21a is D and the diameter of the roller shaft is d, D=d+8 mm or less, so that the heat of the recording paper P moved to the surface of the roller portion 21a is quickly transferred to the roller shaft 21b. It can be moved, and the temperature rise of the roller portion 21a can be suppressed.

(Aspect 5)
In any one of modes 1 to 4, one end of the thermally conductive member such as the heat radiating member 22 has a bearing portion 22a.
According to this, as described in Modification 2, it is possible to prevent the occurrence of sliding noise between the thermally conductive member such as the heat radiating member 22 and the roller shaft 21b.

(Aspect 6)
In any one of modes 1 to 5, at least one of the thermally conductive members such as the roller shaft 21b and the heat radiating member 22 is made of carbon graphite.
According to this, the heat radiation efficiency can be improved compared to the case where both the roller shaft 21b and the thermally conductive member such as the heat radiation member 22 are made of metal.

(Aspect 7)
In any one of modes 1 to 6, an air-cooling means such as a fan 100 for air-cooling a thermally conductive member such as the heat radiating member 22 is provided.
According to this, the thermally conductive member such as the heat radiating member 22 is air-cooled by the air-cooling means such as the fan 100, so that the heat radiation efficiency can be improved and the temperature rise of the roller portion can be suppressed.

(Aspect 8)
An image forming apparatus comprising: image recording means for recording an image on a sheet; fixing means for heating and fixing the recorded image on the sheet; and conveying means for conveying the sheet sent out from the fixing means, wherein: As a means, the conveying device according to any one of modes 1 to 7 was used.
According to this, as described in the embodiment, it is possible to suppress the occurrence of roller marks on an image formed on a recording paper such as a sheet.

2: Image forming section 3: Automatic document feeder 4: Document reading section 10: Image forming unit 20: Fixing device 20a: Fixing roller 20b: Pressure roller 21: Paper ejection drive roller 21a: Roller section 21b: Roller shaft 22: Heat dissipation member 22a: Bearing 22b: Heat dissipation part 22c: Air cooling part 25: Paper discharge driven roller 25a: Driven roller part 25b: Driven roller shaft 26: Paper discharge roller pair 28: Driven heat dissipation member 40: Housing 46: Scanner bracket 47 : Bottom plate 100 : Fan 122c : Fin G : Grease P : Recording paper

JP 2006-225115 A

Claims (7)

a conveying roller having a roller portion that contacts and conveys the sheet that has passed through the heating means and a roller shaft that supports the roller portion;
In a conveying device comprising means for releasing heat from the roller portion,
The means for releasing heat from the roller portion is a thermally conductive member having one end in contact with the roller shaft,
The roller portion is made of a rubber material, and is provided in plurality at predetermined intervals in the axial direction,
A conveying device , wherein one end of the thermally conductive member is abutted between the roller portions of the roller shaft . The conveying device according to claim 1,
The transfer device, wherein the other end of the thermally conductive member is thermally connected to a housing of the main device in which the transfer device is mounted or to a member outside the main device. In the conveying device according to claim 1 or 2,
The roller shaft has a diameter of 10 mm or more,
A conveying device characterized in that D≤d+8 mm, where D is the diameter of the roller portion and d is the diameter of the roller shaft. In the conveying device according to any one of claims 1 to 3,
A conveying device, wherein one end of the thermally conductive member is a bearing portion. In the conveying device according to any one of claims 1 to 4,
At least one of the roller shaft and the thermally conductive member is made of carbon graphite. In the conveying device according to any one of claims 1 to 5,
A conveying apparatus comprising an air-cooling means for air-cooling the heat-conducting member. an image recording means for recording an image on a sheet;
a fixing means for fixing the recorded image by heating the sheet;
In an image forming apparatus comprising a conveying means for conveying a sheet sent out from a fixing means,
An image forming apparatus using the conveying device according to any one of claims 1 to 6 as the conveying means.

Images