JP5151259B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

Conventionally, as an image forming apparatus such as a copying machine or a printer, toner images formed by a plurality of image forming engine units are sequentially transferred onto an intermediate transfer member such as an intermediate transfer belt and superimposed, and then collectively. A so-called intermediate transfer system that transfers onto a recording sheet is widely used.
In recent years, image forming apparatuses have been downsized and installed with components and units that are denser than before, and have a duplex printing function for environmental protection and effective use of resources. It has become common to install.

  In the intermediate transfer type image forming apparatus, when double-sided printing is performed, the paper once heated in the fixing device during the image forming operation on the front surface contacts the intermediate transfer member during the image forming operation on the back surface. As a result, the temperature of the intermediate transfer member rises due to heat transfer from the paper. Therefore, if double-sided printing is repeated, the intermediate transfer body itself is stretched due to the rise in temperature, which may cause disturbance in the formed image. Further, as the temperature of the intermediate transfer member rises, the temperature of the image forming engine unit that contacts the intermediate transfer member also rises, which may cause troubles such as toner sticking.

  On the other hand, in the image forming apparatus, an electric fan is disposed on the back side of the apparatus, and the electric fan generates a flow of cooling air in a direction perpendicular to the rotational movement direction of the intermediate transfer member. There is one configured to cool the intermediate transfer member to suppress the temperature rise (see, for example, Patent Document 1).

JP 2004233345 A

  However, if the flow of the cooling air is generated in the direction perpendicular to the rotational movement direction of the intermediate transfer member, the time for which the cooling air is in contact with the surface of the intermediate transfer member is not sufficient, and it is not always effective cooling. It cannot be said that it is possible.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to enable effective and efficient cooling of an intermediate transfer member in an image forming apparatus that forms an image by an intermediate transfer method using the intermediate transfer member.

The present invention is an image forming apparatus devised to achieve the above object.
The invention according to claim 1 is an intermediate transfer member that is rotationally driven in a predetermined direction, a transfer unit that transfers an image on the intermediate transfer member to a recording medium, and the intermediate transfer member that is more rotationally driven than the transfer unit. a region located downstream in the rotational direction of, in the region and a target cooling region which is hotter than the side farther from the side closer to the transfer portion of the transfer portion, wherein the cooling in the intermediate transfer body an image forming apparatus for cooling the intermediate transfer member to form the flow of cooling air on the 却領 zone, the cooling air flows along the diagonal of the front Symbol the cold 却領 region, and the The image forming apparatus is characterized in that a wind direction is set to oppose a moving direction of the intermediate transfer member in a cooled region .
The invention according to claim 2 includes an electric fan that forms the flow of the cooling air, and the electric fan is driven and controlled so that an exhaust-side flow rate of the cooling air is larger than an intake-side flow rate of the cooling air. The image forming apparatus according to claim 1.
The invention according to claim 3, wherein the air passage regulating means for regulating a flow of cooling air according to claim 1 or characterized in that it is provided is an image forming apparatus according to 2.
Invention, at least the one of the claims 1 to 3 foreign substance removing means for removing foreign matter mix to the cooling air to the exhaust port side of the cooling air, characterized in that it is provided according to claim 4 The image forming apparatus described in the above.

In the invention according to claim 1, on the cold 却領 region in the intermediate transfer member, the intermediate transfer member and the contact area or the contact time of the cooling air, in the direction in which cooling air is orthogonal to the rotational moving direction of the intermediate transfer member as compared with a case where flow can be secured most, as compared with the case where the wind direction of the cooling air follows the moving direction of the intermediate transfer body, improving the cooling effect of the intermediate transfer member can be expected. Accordingly, heat exchange is promoted by that amount, and as a result, the intermediate transfer member can be cooled effectively and efficiently.
In the invention according to claim 2, the flow of the cooling air can be easily and reliably formed, and the flow rate and flow velocity of the cooling air can be controlled easily and reliably.
In the invention according to claim 3 , since the occurrence of the flow deviating from the flow path of the cooling air can be suppressed, the cooling air can flow efficiently, and as a result, an improvement in the cooling effect can be expected.
In the invention according to the fourth aspect , even if foreign matter such as residual toner existing on the intermediate transfer member is mixed with the cooling air, the foreign matter is discharged to the outside of the apparatus along with the cooling air. Can be prevented.

  Hereinafter, an image forming apparatus according to the present invention will be described with reference to the drawings.

[Schematic configuration example of image forming apparatus]
First, a schematic configuration of the image forming apparatus will be described.
FIG. 1 is an explanatory diagram schematically showing an example of a schematic configuration of an image forming apparatus to which the present invention is applied. The image forming apparatus shown in the figure is of a so-called tandem type, and includes four image forming units 13Y corresponding to the respective colors of yellow (Y), magenta (M), cyan (C), and black (K). , 13M, 13C, and 13K are arranged in parallel in the horizontal direction at a predetermined interval.

  The image forming units 13Y, 13M, 13C, and 13K are all configured in the same manner in the present embodiment. The image forming units 13Y, 13M, 13C, and 13K are configured in a similar manner. The surface of the photosensitive drum 15 is exposed to an electrostatic latent image by exposing the surface of the photosensitive drum 15 charged by the charging roll 16 by laser light irradiation. A laser exposure device 14 that forms an image; a developing unit 17 that develops the electrostatic latent image formed on the photosensitive drum 15 using toner (developer) of a predetermined color; and a surface of the photosensitive drum 15. And a cleaning device 18 for cleaning.

  The laser exposure device 14 is configured in common to the four image forming units 13Y, 13M, 13C, and 13K. By driving four semiconductor lasers (not shown) according to the image data of each color, Laser beams LB-Y, LB-M, LB-C, and LB-K are emitted. The laser exposure device 14 may be individually configured for each of a plurality of image forming units. Laser beams LB-Y, LB-M, LB-C, and LB-K emitted from the semiconductor laser are applied to the rotary polygon mirror 19 through an f-θ lens (not shown), and are deflected and scanned by the rotary polygon mirror 19. Is done. Further, the laser beams LB-Y, LB-M, LB-C, and LB-K deflected and scanned by the rotary polygon mirror 19 are obliquely and downwardly transferred onto the photosensitive drum 15 through a plurality of reflection mirrors (not shown). Scan exposure.

  The laser exposure device 14 scans and exposes an image on the photosensitive drum 15 from below. For this reason, toner or the like may fall on the laser exposure device 14 from the four image forming units 13Y, 13M, 13C, and 13K located above, and the laser exposure device 14 may be soiled. is there. For this reason, the periphery of the laser exposure device 14 is sealed by a rectangular parallelepiped frame 20. In addition, four transparent glass windows 21 are provided on the upper portion of the frame 20 as shield members. Each window 21 is a member located at the uppermost position on the optical path along the laser beam LB of the laser exposure apparatus 14. For this reason, the four laser beams LB-Y, LB-M, LB-C, and LB-K are irradiated onto the photosensitive drum 15 through the corresponding windows 21.

  In the present embodiment, the laser exposure device 14 is configured to share a basic part in each image forming unit, but may be provided separately in each image forming unit, and not an LED array but a laser exposure. It may be configured to be exposed by

  The image processing unit 12 sequentially outputs image data of each color to the laser exposure device 14 provided in common to the image forming units 13Y, 13M, 13C, and 13K of each color of YMCK. The electrostatic latent image formed on the photosensitive drum 15 is developed as a toner image (visible image) of each color of YMCK by the corresponding developing device 17. Corresponding color toners are supplied from the toner cartridges 44Y, 44M, 44C, and 44K to the developing devices 17 included in the image forming units 13Y, 13M, 13C, and 13K of the respective colors.

  The YMCK color toner images sequentially formed on the photoconductive drums 15 of the image forming units 13Y, 13M, 13C, and 13K are arranged in strips over the image forming units 13Y, 13M, 13C, and 13K. A plurality of images are transferred onto an intermediate transfer belt 25 as an intermediate transfer member by primary transfer rolls 26Y, 26M, 26C, and 26K (collectively referred to as “primary transfer roll 26”). The primary transfer rolls 26Y, 26M, 26C, and 26K are provided as transfer members in the corresponding image forming units 13Y, 13M, 13C, and 13K. The primary transfer rolls 26Y, 26M, 26C, and 26K are each composed of a metal roll, for example, for the purpose of reducing the price and extending the life.

  The intermediate transfer belt 25 is wound around with a predetermined tension using a plurality of support rolls including a drive roll 27, a backup roll 28 and a tension roll 23. The drive roll 27 is rotationally driven in a clockwise direction in the drawing by a drive motor having a constant speed (not shown). The intermediate transfer belt 25 is rotationally driven in one direction according to the rotation of the drive roll 27. Further, the backup roll 28 and the tension roll 23 rotate in accordance with the rotation of the intermediate transfer belt 25, respectively. As the intermediate transfer belt 25, for example, a flexible synthetic resin film such as polyimide or PET is formed in a strip shape, and both ends of the synthetic resin film are joined by means such as welding, thereby forming an endless belt shape. And those formed endless from the beginning are used.

  The photosensitive drums 15 of the image forming units 13Y, 13M, 13C, and 13K are disposed below the intermediate transfer belt 25 in the vertical direction. In addition, the photosensitive drums 15 of the image forming units 13Y, 13M, 13C, and 13K are arranged close to the corresponding primary transfer rolls 26Y, 26M, 26C, and 26K. An intermediate transfer belt 25 is passed between the photosensitive drums 15 of the image forming units 13Y, 13M, 13C, and 13K adjacent to each other and the primary transfer rolls 26Y, 26M, 26C, and 26K.

  In each of the image forming units 13Y, 13M, 13C, and 13K, the surface of the photosensitive drum 15 provided individually is uniformly charged by the charging roll 16 for primary charging. Thereafter, the surface of the photosensitive drum 15 is subjected to scanning exposure with an image forming laser beam LB emitted from the laser exposure device 14 in accordance with image data. Thereby, an electrostatic latent image corresponding to the image data of each color is formed on the surface of the photosensitive drum 15. The laser beam LB scanned and exposed on the photosensitive drum 15 is set so as to be exposed at a predetermined inclination angle from an obliquely lower side slightly to the right side from directly below the photosensitive drum 15. The electrostatic latent image formed on the photosensitive drum 15 is developed with yellow, magenta, cyan, and black toners by the developing units 17 of the image forming units 13Y, 13M, 13C, and 13K, respectively. Become. The toner images of the respective colors are sequentially transferred onto the intermediate transfer belt 25 by the primary transfer roll 26.

  The YMCK toner images transferred onto the intermediate transfer belt 25 in a multiple manner are secondarily transferred onto a sheet (recording medium) 30 by a secondary transfer roll 29 that is pressed against the backup roll 28 by a pressing force and an electrostatic force. Is done. The sheet 30 on which the toner images of the respective colors are thus transferred is conveyed to a fixing device 31 positioned above. The secondary transfer roll 29 is in pressure contact with the side of the backup roll 28 and is configured to secondary-transfer toner images of each color onto a sheet 30 conveyed from below to above. The paper 30 on which the toner images of the respective colors are transferred is subjected to a fixing process by heat and pressure by a fixing device 31 and then discharged onto a discharge tray 33 provided on the upper portion of the main body 1 by a discharge roll 32.

  A sheet 30 having a predetermined size is conveyed from a sheet feeding cassette 34 to a registration roll 38 via a sheet conveying path 37 by a sheet feeding roll 35 and a sheet separating / conveying roll pair 36 and temporarily stopped there. The paper 30 thus supplied from the paper feed cassette 34 is sent to the secondary transfer position of the intermediate transfer belt 25 by a registration roll 38 that rotates at a predetermined timing.

  In the case of making full-color double-sided copying, the paper 30 with the image fixed on one side is not discharged onto the discharge tray 33 as it is by the discharge roll 32, but the conveyance direction is switched by a switching gate (not shown), It conveys to the conveyance part 40 for both surfaces via the roll pair 39 for conveyance. In the double-sided conveyance unit 40, the sheet 30 is conveyed again to the registration roll 38 in a state where the front and back of the sheet 30 are reversed by a conveyance roll pair (not shown) provided along the conveyance path 41. This time, after the image is transferred and fixed on the back surface of the paper 30, the paper 30 is discharged onto the discharge tray 33 by the discharge roll 32.

  Further, residual toner, paper dust, and the like are removed from the surface of the photosensitive drum 15 after the toner image transfer process is completed by the cleaning device 18 to prepare for the next image forming process. On the other hand, residual toner, paper dust, and the like are removed from the surface of the intermediate transfer belt 25 after the toner image transfer process is completed by the cleaning device 43 to prepare for the next image forming process. The cleaning device 43 includes a cleaning brush 43a and a cleaning blade 43b. The cleaning brush 43a and the blade 42 remove residual toner, paper dust, and the like on the intermediate transfer belt 25.

  FIG. 2 is an explanatory diagram schematically showing another example of the schematic configuration of the image forming apparatus to which the present invention is applied. The image forming apparatus shown in the figure is of a so-called rotary type, and the toner image of each color of YMCK on the photosensitive drum 15 is sequentially formed while the developing device 17 rotates. That is, in the rotary type image forming apparatus, the photosensitive drum 15 that is rotationally driven, the charging roll 16 that uniformly charges the surface of the photosensitive drum 11, and the electrostatic latent image on the surface of the photosensitive drum 15. A laser exposure device 14 for forming a toner image, a developing device 17 for developing a latent electrostatic image on the photosensitive drum 15 to form a toner image, and an intermediate transfer belt formed in an endless belt shape and driven to circulate at the same speed 25, a primary transfer roll 26 for transferring the toner image on the photosensitive drum 15 onto the intermediate transfer belt 25, a cleaning device 18 for removing foreign matters such as residual toner and paper dust on the photosensitive drum 15, and intermediate transfer A secondary transfer roll 29 that transfers a toner image on the belt 25 onto a sheet 30 such as a recording sheet, and a cleaning device 43 that removes foreign matters such as residual toner and paper dust on the intermediate transfer belt 25. The toner image is configured to have a fixing device 31 which performs fixing processing by heat and pressure performs fixing the transferred image on the sheet 30 to the sheet 30 after transfer, the. Then, image formation is performed through each process of charging → exposure → development → transfer → fixing.

  As described above, the image forming apparatus to which the present invention is applied can perform image formation using the intermediate transfer belt 25 as an intermediate transfer member, and the image forming units 13Y, 13M, and YM corresponding to the respective colors of YMCK. Either a tandem type in which 13C and 13K are juxtaposed (see FIG. 1) or a rotary type in which the developing device 17 sequentially develops toner images of each color of YMCK (see FIG. 2) It does not matter.

[Configuration example of main part of image forming apparatus]
Next, the configuration of the main part of the image forming apparatus will be described.
The image forming apparatus to which the present invention is applied is configured to cool the intermediate transfer belt 25 using an air flow in order to suppress the temperature increase of the intermediate transfer belt 25. That is, one plane area on the surface of the intermediate transfer belt 25 is secured as a cooled plane area, and a cooling air flow path is formed on the cooled plane area, whereby the intermediate transfer belt 25 is cooled. It has become.

It is conceivable to secure the cooled plane region downstream of the secondary transfer roll 29 in the rotation direction of the intermediate transfer belt 25. This is because heat transfer from the paper 30 that passes through the place where the secondary transfer roll 29 is installed can cause the temperature of the intermediate transfer belt 25 to rise.
The size of the plane area to be cooled is not particularly limited, but may be a rectangular shape having one side corresponding to the width of the intermediate transfer belt 25.

  Hereinafter, the configuration for cooling the intermediate transfer belt 25 will be described in detail with specific examples.

[First configuration example]
FIG. 3 is a plan view showing a first specific example of the main configuration of the image forming apparatus according to the present invention.
In the illustrated image forming apparatus, one rectangular plane area on the intermediate transfer belt 25 is secured as the cooled plane area 51. On the cooled flat area 51, the surface of the intermediate transfer belt 25 moves in a predetermined direction (see arrow A in the figure).

  Air inside the image forming apparatus is discharged outside the vicinity of one of the tops constituting the cooled planar region 51, more specifically, near the top located upstream in the movement direction of the intermediate transfer belt 25. An electric fan 52 is provided for this purpose. Further, in the vicinity of the top portion where the electric fan 52 is disposed and the other top portion facing each other on the diagonal line of the cooled plane region 51 (near the extension line of the diagonal line), outside air is taken into the image forming apparatus. An intake port (not shown) is provided.

  In such a configuration, when the electric fan 52 is driven, air flows from the air inlet toward the electric fan 52 on the cooled plane region 51. That is, by driving the electric fan 52, a cooling air flow path (see arrow B in the figure) arranged along the diagonal line of the cooled plane region 51 is formed on the cooled plane region 51.

  This means that the contact area between the intermediate transfer belt 25 and the cooling air on the cooled flat area 51 is larger than when the cooling air flows in a direction perpendicular to the rotational movement direction of the intermediate transfer belt 25. To do. Furthermore, if the wind speed is the same, the distance of the cooling air flow path becomes longer, and the contact time between the intermediate transfer belt 25 and the cooling air also increases. As the contact area and contact time increase, heat exchange is promoted accordingly. Therefore, if the cooling air flow path is arranged along the diagonal line of the cooled plane region 51, the cooling of the intermediate transfer belt 25 is more effective and cooler than the case where it is arranged in the direction orthogonal to the rotational movement of the intermediate transfer belt 25. It can be done efficiently.

  The “diagonal line” referred to here is a line segment excluding a side among line segments connecting two different vertices in a polygon of quadrilateral or more. Accordingly, a plurality of diagonal lines may exist in the cooled plane region 51, but in this case, the diagonal line along which the cooling air flow path is arranged is not particularly limited, and each of the components in the image forming apparatus is not limited. What is necessary is just to determine arbitrarily, considering arrangement | positioning. Moreover, the to-be-cooled plane area 51 does not necessarily have to be a rectangular area, and may be a polygonal area having a quadrangle or more.

  The flow path of the cooling air can also be formed by arranging an electric fan on the intake side. However, as described above, if the electric fan 52 is arranged on the exhaust side to form the cooling air flow path, it becomes easy to make the exhaust air flow rate of the cooling air larger than the intake air flow rate of the cooling air. As a result, it is possible to facilitate and ensure the formation of the flow path as compared with the case where the electric fan is disposed on the intake side. In addition, control of the flow rate and flow rate of the cooling air can be performed easily and reliably.

The electric fan 52 for forming the cooling air flow path is arranged on the upstream side in the moving direction of the intermediate transfer belt 25. Accordingly, the flow direction of the cooling air formed by the electric fan 52 is set so as to resist the moving direction of the intermediate transfer belt 25 in the cooled plane region 51.
When the airflow direction of the cooling air opposes the moving direction of the intermediate transfer belt 25, the relative speed between the airflows becomes larger than when the airflow direction of the cooling air follows the moving direction of the intermediate transfer belt 25. For this reason, the flow of the cooling air on the cooled plane region 51 is more likely to be turbulent rather than laminar. That is, positive heat exchange with the surface of the intermediate transfer belt 25 is promoted by the generation of turbulent flow. Therefore, if the direction of the cooling air is set to resist the moving direction of the intermediate transfer belt 25, As compared with the case where the direction of the cooling air follows the moving direction of the intermediate transfer belt 25, an improvement in the cooling effect on the intermediate transfer belt 25 can be expected.

[Second configuration example]
FIG. 4 is a plan view showing a second specific example of the main configuration of the image forming apparatus according to the present invention.
In the illustrated image forming apparatus, in addition to an electric fan (hereinafter referred to as “exhaust fan”) 52 provided on the exhaust side, an electric fan (hereinafter referred to as “intake fan”) 53 is also provided on the exhaust side. Yes. In this case, if the power or driving speed of these fans 52 and 53 is set so that the cooling air flow rate by the exhaust fan 52 is larger than the cooling air flow rate by the intake fan 53, the exhaust side flow rate becomes larger than the intake side flow rate. As a result, as in the case of the first configuration example described above, the formation of the cooling air flow path can be facilitated and ensured, and the flow rate and flow rate of the cooling air can be easily controlled. It will surely be possible.

  Between the exhaust fan 52 and the intake fan 53, a duct 54 is disposed as an air path restricting means for restricting the flow of cooling air. One end of the duct 54 is connected via an intake duct 55 and a buffer material 56 communicating with the intake fan 53, and the other end is connected via an exhaust duct 57 and a buffer material 58 communicating with the exhaust fan 52. Has been. The buffer materials 56 and 58 are for reducing the influence of vibration and the like, and may be formed of an elastic material such as a rubber material or a sponge material.

  The duct 54 is not particularly limited in its cross-sectional shape, forming material, and the like as long as it allows heat exchange between the cooling air and the intermediate transfer belt 25 while restricting the flow of the cooling air. For example, by arranging a member having a channel-like cross section (a cross-sectional state in which one surface is open but the other three surfaces are surrounded) so that the open surface faces the intermediate transfer belt 25 side, the duct 54 is arranged. It is conceivable to configure. In addition, for example, if the member has good heat transfer, such as metal, the duct 54 may be configured by forming the member having a square or circular cross section into a cylindrical shape. In that case, heat exchange between the cooling air and the intermediate transfer belt 25 is performed via the wall surface of the duct 54.

  In the image forming apparatus having such a configuration, a cooling air flow path is formed by the exhaust fan 52, the intake fan 53, and the duct 54 on the cooled plane region 51, and the air flow deviates from the flow path by the duct 54. Occurrence of existence is suppressed. Accordingly, the cooling air efficiently flows on the cooled plane region 51, and as a result, an improvement in the cooling effect on the intermediate transfer belt 25 can be expected.

  Further, on the exhaust air outlet side of the cooling air, specifically, on the downstream side of the exhaust fan 52, a dustproof filter 59 as a foreign matter removing means for removing foreign matter mixed in the cooling air, and a device on the downstream side of the dustproof filter 59 are provided. A discharge duct 60 extending to the outside is disposed. The dustproof filter 59 is disposed at least on the exhaust air side of the cooling air. Accordingly, the cooling air may be disposed not only on the exhaust air side but also on the cooling air intake side. The dustproof filter 59 is not particularly limited as long as it can remove foreign matters mixed in the cooling air, and it can be considered to be configured using a known HEPA filter.

  In this way, if the dustproof filter 59 is disposed at least on the exhaust air outlet side of the cooling air, even if foreign matter such as residual toner existing on the intermediate transfer belt 25 is mixed with the cooling air, the foreign matter is not removed. It will not be discharged outside the device on the cooling air.

[Third configuration example]
FIG. 5 is a plan view showing a third specific example of the main configuration of the image forming apparatus according to the present invention.
Also in the image forming apparatus shown in the figure, the cooling air flows from the intake fan 53, the intake duct 55, the buffer material 56, the duct 54, the buffer material 58, the exhaust duct 57, and the exhaust fan as in the case of the second configuration example described above. 52 is configured to flow through 52.

  In the image forming apparatus having such a configuration, the intermediate transfer belt 25 has the highest temperature in the upstream side in the moving direction of the intermediate transfer belt 25 (see the area C in the drawing) on the cooled plane area 51. Then, the hottest point is cooled by natural air cooling by moving toward the downstream side, or cooled by heat exchange with cooling air flowing through the duct 54 when passing through the place where the duct 54 is disposed. Is done. As a result, the temperature of the intermediate transfer belt 25 is lower than that of the region C at the downstream side in the moving direction of the intermediate transfer belt 25 on the cooled planar region 51 (see region D in the figure). Become.

  Here, for comparison, a cooling mode in the case where the cooling air flows in a direction orthogonal to the rotational movement direction of the intermediate transfer belt 25 as in the prior art will be briefly described. For example, if the cooling air is supplied downstream in the moving direction of the intermediate transfer belt 25, the vicinity of the edge on the cooling air inlet side and the vicinity of the edge on the cooling air exhaust port side of the intermediate transfer belt 25. Both of them are cooled by heat exchange with cooling air after natural cooling. However, the temperature of the cooling air rises as it approaches the vicinity of the edge on the cooling air exhaust port side by heat exchange with the intermediate transfer belt 25. That is, the temperature of the cooling air is different between the vicinity of the edge on the cooling air inlet side and the vicinity of the edge on the cooling air exhaust side. Therefore, when the cooling air is passed in a direction orthogonal to the rotational movement direction of the intermediate transfer belt 25, the temperature of the intermediate transfer belt 25 after cooling by the cooling air reflects the temperature difference of the cooling air, and the cooling air The portion near the edge on the intake port side and the portion near the edge on the cooling air exhaust port side are not uniform.

  On the other hand, as described above, when the cooling air flow path is disposed along the diagonal line of the cooled plane region 51, the vicinity of the edge of the intermediate transfer belt 25 on the cooling air inlet side (in the drawing) In the arrow E), after natural cooling accompanying the movement of the intermediate transfer belt 25, it is cooled by heat exchange with cooling air. On the other hand, in the vicinity of the edge on the cooling air exhaust port side of the intermediate transfer belt 25 (see arrow G in the figure), after being cooled by heat exchange with the cooling air, it is naturally cooled as the intermediate transfer belt 25 moves. The Further, these intermediate portions (see arrow F in the figure) are cooled through respective intermediate processes. That is, even if the cooling air becomes higher as it approaches the cooling air exhaust port side, the portion near the edge on the cooling air exhaust port side is closer to the cooling air exhaust port side until it reaches the region D. It is considered that the time for natural cooling in the meantime becomes longer, and this causes an increase in the temperature drop.

  Therefore, if the cooling air flow path is arranged along the diagonal line of the plane area 51 to be cooled, the cooling air flows in the region D as compared with the case where the cooling air flows in a direction perpendicular to the rotational movement direction of the intermediate transfer belt 25. In addition, the influence of the temperature difference in the cooling air can be alleviated, and the temperature non-uniformity between the cooling air intake side and the cooling air exhaust side can be corrected.

[Fourth configuration example]
FIG. 6 is a plan view showing a fourth specific example of the main configuration of the image forming apparatus according to the present invention.
In the image forming apparatus of the illustrated example, as in the case of the second configuration example or the third configuration example described above, the cooling air is supplied by the intake fan 53, the intake duct 55, the buffer material 56, the duct 54, the buffer material 58, It is configured to flow through the exhaust duct 57 and the exhaust fan 52.

  However, the exhaust fan 52 among these functions also as an electric fan for exhausting heat generated from the fixing device 31. That is, the exhaust fan 52 has a function as an electric fan for cooling the intermediate transfer belt 25 and a function as an electric fan for cooling the fixing device 31. In order to combine these functions, an electric fan provided in a general image forming apparatus may be used to exhaust heat from the fixing device 31 and the exhaust duct 57 may be extended to the electric fan. Note that the function shared by the exhaust fan 52, that is, the cooling target to be shared, does not necessarily have to be the fixing device 31, but may be another component of the image forming apparatus.

  As described above, if the exhaust fan 52 for cooling the intermediate transfer belt 25 is configured using the electric fan disposed for the other components of the image forming apparatus, the apparatus configuration is simplified and the configuration is simplified. Reduction of the number of parts can be realized, and accordingly, downsizing and cost reduction of the image forming apparatus can be easily realized.

  In each of the configuration examples described above, preferred specific examples of the present invention have been described. However, the present invention is not limited to the contents, and can be appropriately changed without departing from the gist thereof. It is.

1 is an explanatory diagram schematically illustrating an example of a schematic configuration of an image forming apparatus to which the present invention is applied. It is explanatory drawing which shows typically the other example of schematic structure of the image forming apparatus with which this invention is applied. 1 is a plan view illustrating a first specific example of a main part configuration of an image forming apparatus according to the present invention. It is a top view which shows the 2nd specific example of the principal part structure of the image forming apparatus which concerns on this invention. FIG. 6 is a plan view showing a third specific example of the main configuration of the image forming apparatus according to the present invention. It is a top view which shows the 4th example of the principal part structure of the image forming apparatus which concerns on this invention.

Explanation of symbols

  25 ... Intermediate transfer belt, 51 ... Plane area to be cooled, 52 ... Exhaust fan (electric fan), 53 ... Intake fan, 54 ... Duct, 59 ... Dust-proof filter

Claims (4)

An intermediate transfer member that is rotationally driven in a predetermined direction ;
A transfer portion for transferring an image on the intermediate transfer member to a recording medium;
A region to be cooled in the intermediate transfer body that is located downstream of the transfer unit in the rotational direction of the rotation drive, and in which the side closer to the transfer unit is higher than the side farther from the transfer unit When,
With
Wherein an image forming device for cooling the intermediate transfer member to form the flow of cooling air onto the cold 却領 region in the intermediate transfer member,
The cooling air, before SL flows along the diagonal of the cold 却領 region, and, wherein the wind direction is set to resist the moving direction of the intermediate transfer body in the cooling zone Image forming apparatus. 2. The electric fan is provided so as to form a flow of the cooling air, and the electric fan is driven and controlled so that an exhaust-side flow rate of the cooling air is larger than an intake-side flow rate of the cooling air. The image forming apparatus described. Said air passage regulating means for regulating a flow of cooling air according to claim 1 or characterized in that it is disposed in the image forming apparatus according to 2. The image forming apparatus according to any one of claims 1 to 3 , wherein a foreign matter removing unit that removes foreign matter mixed in the cooling air is disposed at least on an exhaust port side of the cooling air.

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