JP2016184120A - Conveying device, cooling device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling device that reduces a load on conveyance by a belt compared with a case where suppression means is not included that suppresses electrical charge from being induced to a contact member in contact with a conveyance target member via the belt.SOLUTION: A conveying device comprises: an endless first belt 73 that moves in circulation; an endless second belt 75 that is arranged on the outer peripheral side of the first belt 73, and moves in circulation while holding a recording sheet 5 with the first belt 73 to convey the recording sheet 5; a heat sink 74 that is arranged on the inner peripheral side of the first belt 73 and in contact, with the first belt 73 therebetween, with the recording sheet 5 conveyed by the first and second belts 73 and 75; and a high resistance R as suppression means that suppresses electrical charge from being induced to an end side of the heat sink 74 where the first belt 73 starts contact therewith.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a conveyance device, a cooling device, and an image forming apparatus.

  Conventionally, those disclosed in Patent Documents 1 to 4 have already been proposed as technologies related to the cooling device. Patent Document 1 discloses a configuration in which the surface of the cooling means that comes into contact with the heat-resistant belt is subjected to a treatment for reducing the contact friction coefficient (paragraph [0017]). Patent Document 2 discloses a configuration including a pressing member that presses a recording material conveyed by a belt member against a curved portion side of a cooling body. Patent Document 3 includes a pressing force variable unit that changes the pressing force of the pressing member that presses the belt member against the cooling mechanism to the cooling mechanism. Patent Document 4 is configured so that a plurality of cooling members arranged on the inner peripheral surface of the endless belt are independently movably supported and urged toward the inner peripheral surface of the endless belt.

JP-A-5-27603 JP 2009-161347 A JP 2013-109028 A JP 2013-1114094 A

  An object of the present invention is to reduce a belt conveyance load as compared with a case where no suppression means is provided that suppresses the induction of electric charges in a contact member that is in contact with the member to be conveyed via the belt.

The invention described in claim 1 includes an endless first belt that circulates and moves,
An endless second belt that is disposed on the outer peripheral side of the first belt, circulates and moves with the conveyed member sandwiched between the first belt, and conveys the conveyed member;
A contact member disposed on the inner peripheral side of the first belt and in contact with the transported member transported by the second belt via the first belt;
Suppression means for suppressing charge induction on the end side of the contact member where the first belt starts contact;
It is a conveyance apparatus provided with.

  According to a second aspect of the present invention, in the first aspect, the suppressing means comprises means for grounding the contact member through a predetermined high resistance or bringing the contact member into an electrically floating state. It is a conveyance apparatus of description.

  According to a third aspect of the present invention, in the conveying device according to the first aspect, the suppressing means comprises a predetermined high resistance member or insulating member interposed between the contact member and the first belt. It is.

  The invention described in claim 4 is arranged on the inner peripheral side of the second belt, and the first belt presses the second belt against the end portion side of the contact member that starts contact with the contact member. It is a conveying apparatus in any one of Claims 1 thru | or 3 provided with a pressing member.

  According to a fifth aspect of the present invention, there is provided a pressing device for partially reducing a pressing force with which the pressing member presses the second belt against the contact member on at least one of the pressing member and the contact member. It is a conveying apparatus of Claim 4 provided with a force reduction part.

  According to a sixth aspect of the present invention, the contact member comprises a cooling member that cools the transported member via the first belt, and cooling as the transport device according to any one of the first to fifth aspects. Device.

The invention described in claim 7 is an image forming unit that forms an image on a recording medium;
Fixing means for fixing by heating a recording medium on which an image is formed by the image forming unit;
The image forming apparatus including the cooling device according to claim 6, wherein the recording medium on which the image is fixed by the fixing unit is cooled as the transported member.

  According to the first aspect of the present invention, compared to the case where the member to be transported is not provided with the suppression means for suppressing the induction of electric charge to the contact member that contacts via the belt, the transport load of the belt is reduced. Can be reduced.

  According to the second aspect of the present invention, the suppression means is compared with a case where the contact means is not composed of means for grounding the contact member through a predetermined high resistance or for electrically contacting the contact member. Thus, the belt conveyance load can be reduced with a simple configuration.

  According to the invention described in claim 3, compared with a case where the suppressing means is not constituted by a predetermined high resistance member or insulating member interposed between the contact member and the first belt, it is simpler. The belt conveyance load can be reduced with the configuration.

  According to the invention described in claim 4, compared to a case where the first belt does not include a pressing member that presses the second belt on the end side of the contact member that starts contact with the contact member, The member can be reliably brought into contact with the contact member via the first belt.

  According to the fifth aspect of the present invention, it is possible to further reduce the belt conveyance load as compared with the case where the pressing force reducing portion is not provided.

  According to the sixth aspect of the present invention, compared to the case where the contact member is not composed of a cooling member that cools the conveyed member via the first belt, the conveyed member can be efficiently cooled. .

  According to the seventh aspect of the present invention, compared to the case where the cooling device according to the sixth aspect is not provided, the belt conveyance load can be reduced while maintaining the cooling performance of the recording medium. .

1 is a configuration diagram showing an outline of an image forming apparatus to which a conveying device according to Embodiment 1 of the present invention is applied. 2 is a configuration diagram illustrating an image forming unit of the image forming apparatus. FIG. It is a block diagram which shows the cooling device as a conveying apparatus which concerns on Embodiment 1 of this invention. It is a schematic block diagram which shows the principal part of the cooling device as a conveying apparatus which concerns on Embodiment 1 of this invention. FIG. 4A is a schematic configuration diagram showing the operation of the conventional cooling device, and FIG. 4B is a schematic configuration diagram showing the operation of the cooling device as the transfer device according to Embodiment 1 of the present invention. It is a schematic block diagram which shows the principal part of the cooling device as a conveying apparatus which concerns on Embodiment 2 of this invention. It is a schematic block diagram which shows the principal part of the cooling device as a conveying apparatus which concerns on Embodiment 3 of this invention. The same figure (a) is a schematic block diagram which shows the principal part of the cooling device as a conveying apparatus based on Embodiment 4 of this invention, The same figure (b) is XX sectional drawing of the same figure (a). . FIG. 4A is a schematic configuration diagram showing the operation of a conventional cooling device, and FIG. 4B is a schematic configuration diagram showing the operation of the cooling device as a transfer device according to Embodiment 4 of the present invention. The same figure (a) is a schematic block diagram which shows the cooling device as a conveying apparatus based on Embodiment 5 of this invention, The same figure (b) is a plane block diagram. The same figure (a) is a schematic block diagram which shows the cooling device as a conveying apparatus based on Embodiment 6 of this invention, The same figure (b) is a plane block diagram. It is a schematic block diagram which shows the modification of the cooling device as a conveying apparatus which concerns on Embodiment 6 of this invention. It is a schematic block diagram which shows the cooling device as a conveying apparatus which concerns on Embodiment 7 of this invention. It is a graph which shows the drive current of a conveyance belt. It is a graph which shows the drive current of a conveyance belt. It is a schematic block diagram which shows the cooling device as a conveying apparatus which concerns on Embodiment 8 of this invention. It is a schematic diagram which shows the surface of the heat sink which concerns on the modification of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, modes for carrying out the present invention (simply referred to as “embodiments”) will be described with reference to the accompanying drawings.

[Embodiment 1]
1 and 2 show an image forming apparatus to which the conveying device and the cooling device according to the first embodiment are applied. FIG. 1 shows an outline of the entire image forming apparatus, and FIG. 2 shows an enlarged main part (image forming apparatus, etc.) in the image forming apparatus.

<Overall Configuration of Image Forming Apparatus>
The image forming apparatus 1 according to the first embodiment is configured as a color printer, for example. The image forming apparatus 1 holds a plurality of image forming apparatuses 10 that form toner images developed with toner constituting the developer 4 and the toner images formed by the respective image forming apparatuses 10 and finally An intermediate transfer device 20 that transports the recording sheet 5 as an example of a transported member (recording medium) to a secondary transfer position for secondary transfer, and a required recording sheet 5 to be supplied to the secondary transfer position of the intermediate transfer device 20 A sheet feeding device 50 that accommodates and conveys the toner, and a fixing device 40 that fixes the toner image on the recording paper 5 secondarily transferred by the intermediate transfer device 20.

  The image forming apparatus 1 includes a first housing 1a and a second housing 1b, and the first and second housings 1a and 1b are formed of a support structure member, an exterior cover, and the like. In addition, a two-dot chain line in the figure indicates a main conveyance path through which the recording paper 5 is conveyed inside the first and second casings 1a and 1b.

  The image forming apparatus 10 exclusively forms four color toner images of yellow (Y), magenta (M), cyan (C), and black (K) and two types of toner images of special colors S1 and S2. It is composed of six image forming apparatuses 10Y, 10M, 10C, 10K, 10S1, and 10S2. These six image forming devices 10 (S1, S2, Y, M, C, K) are arranged in a line in the internal space of the first housing 1a. As the developer 4 (S1, S2) of the special color (S1, S2), for example, those composed of color materials that are difficult or impossible to express with the above four colors are used. Is a toner of a color other than the above four colors, a toner having the same color as that of the above four colors and having a different saturation, a metal color toner such as gold or silver, a white toner for improving the whiteness of the recording paper 5, Transparent toner for improving gloss, foamable toner for Braille, fluorescent color toner, and the like. In addition, the image forming apparatuses 10 (S1, S2, Y, M, C, and K) have substantially the same configuration as described below except that the types of developers to be handled are different.

  Each image forming apparatus 10 (S1, S2, Y, M, C, and K) includes a photosensitive drum 11 as an example of a rotating image carrier, as shown in FIG. 1 and FIG. The following devices are mainly arranged around the photosensitive drum 11. The main devices are a charging device 12 that charges a peripheral surface (image holding surface) on the photosensitive drum 11 on which an image can be formed to a required potential, and image information (on the charged peripheral surface of the photosensitive drum 11). The exposure device 13 as an electrostatic latent image forming unit that irradiates the light LB based on the signal) to form an electrostatic latent image (for each color) having a potential difference, and the corresponding electrostatic latent image (S1, S1). A developing device 14 (S1, S2, Y, M, C, K) as developing means for developing a toner image by developing with the toner of the developer 4 (S2, Y, M, C, K) and each toner image thereof A primary transfer device 15 that transfers the toner to the intermediate transfer device 20, a drum cleaning device 16 that removes and removes adhering matter such as toner remaining on the image holding surface of the photoconductor drum 11 after the primary transfer, and a photoconductor A static eliminator 17 or the like that neutralizes the image holding surface after cleaning the drum 11. .

  The photosensitive drum 11 is formed by forming an image holding surface having a photoconductive layer (photosensitive layer) made of a photosensitive material on the peripheral surface of a cylindrical or columnar base material to be grounded. The photosensitive drum 11 is supported so as to rotate in a direction indicated by an arrow A when power is transmitted from a rotation driving device (not shown).

  The charging device 12 is configured by a non-contact type charging device such as a corona discharger that is disposed without being in contact with the photosensitive drum 11. A charging voltage is supplied to the charging device 12. As the charging voltage, when the developing device 14 performs reversal development, a voltage or current having the same polarity as the charging polarity of the toner supplied from the developing device 14 is supplied.

  The exposure device 13 irradiates light (solid line with arrows) LB configured according to image information input to the image forming device 1 onto the peripheral surface of the charged photosensitive drum 11 to statically. It forms an electrostatic latent image. When the latent image is formed, image information (signal) input to the image forming apparatus 1 by any means is transmitted to the exposure apparatus 13.

  As shown in FIG. 2, each of the developing devices 14 (S1, S2, Y, M, C, and K) includes a developer in a housing 140 in which an opening and a storage chamber for the developer 4 are formed. 4, a developing roll 141 that conveys the developer 4 to a developing area facing the photosensitive drum 11, a stirring conveyance member such as a screw auger (not shown) that conveys the developer 4 while passing the developing roll 141 while stirring, and a developing roll A layer thickness regulating member (not shown) that regulates the amount (layer thickness) of the developer held at 141 is arranged. A developing voltage is supplied to the developing device 14 from a power supply device (not shown) between the developing roll 141 and the photosensitive drum 11. Further, the developing roller 141 and the agitating / conveying member (not shown) are rotated in a required direction by receiving power from a rotation driving device (not shown). Further, as the four color developers 4 (Y, M, C, K) and the two special color developers 4 (S1, S2), a two-component developer containing a non-magnetic toner and a magnetic carrier is used. Is done. In FIG. 1, reference numeral 142 denotes a toner cartridge that contains a developer containing at least the corresponding color toner to be supplied to the developing device 14 (S1, S2, Y, M, C, K).

  The primary transfer device 15 is in contact with the peripheral surface of the photosensitive drum 11 at the primary transfer position T1 via the intermediate transfer belt 21 and rotates, and a contact type transfer device including a primary transfer roll to which a primary transfer voltage is supplied. It is. As the primary transfer voltage, a DC voltage having a polarity opposite to the charging polarity of the toner is supplied from a power supply device (not shown).

  As shown in FIG. 2, the drum cleaning device 16 is disposed inside a container-shaped main body (not shown), removes adhered matters such as residual toner, and cleans the toner, and the toner removed by the cleaning plate 161. It is comprised by sending members, such as a screw auger which is not shown in figure, which conveys so that a deposit may be collected and sent out to a recovery system. As the cleaning plate 161, a plate-like member (for example, a blade) made of a material such as rubber is used.

  As shown in FIG. 1, the intermediate transfer device 20 is disposed so as to exist at a position below each image forming device 10 (S1, S2, Y, M, C, K). The intermediate transfer device 20 includes an intermediate transfer belt 21 that circulates in a direction indicated by an arrow B while passing through a primary transfer position T1 between the photosensitive drum 11 and the primary transfer device 15 (primary transfer roll), and an intermediate transfer belt. A plurality of belt support rolls 22 to 28 that hold the belt 21 in a desired state from the inner surface thereof and support the belt 21 so as to be freely circulated, and an outer peripheral surface (image holding surface) of the intermediate transfer belt 21 supported by the belt support roll 26. A secondary transfer device 30 disposed on the side for secondary transfer of the toner image on the intermediate transfer belt 21 to the recording paper 5 and remaining on the outer peripheral surface of the intermediate transfer belt 21 after passing through the secondary transfer device 30 And a belt cleaning device 29 that removes and removes adherents such as toner and paper dust.

  As the intermediate transfer belt 21, for example, an endless belt made of a material in which a resistance adjusting agent such as carbon black is dispersed in a synthetic resin such as polyimide resin or polyamide resin is used. The belt support roll 22 is configured as a drive roll, the belt support rolls 23, 25, 27, and 28 are configured as driven rolls that hold the travel position of the intermediate transfer belt 21, and the belt support roll 24 is configured as a tension applying roll. The belt support roll 26 is configured as a secondary transfer backup roll.

  As shown in FIG. 1, the secondary transfer device 30 rotates at a secondary transfer position T <b> 2 that is an outer peripheral surface portion of the intermediate transfer belt 21 supported by the belt support roll 26 in the intermediate transfer device 20. Consists of roles. Further, a DC voltage having a polarity opposite or the same as the charging polarity of the toner is supplied to the support roll 26 of the secondary transfer device 30 or the intermediate transfer device 20 as a secondary transfer voltage.

  In this embodiment, the image forming device 10 (S1, S2, Y, M, C, K), the intermediate transfer device 20, and the secondary transfer device 30 constitute an image forming unit.

  A fixing device 40 as an example of a fixing unit is disposed inside a casing 41 and is rotated by a driving roll 42 in a direction indicated by an arrow, and an inner surface as an example of a heating unit so that the surface temperature is maintained at a predetermined temperature. A fixing belt 45 heated by the heating roll 43 and the external heating roll 44, and a pressure roll 46 that rotates in contact with the fixing belt 45 wound around the driving roll 42 at a required pressure are arranged. It is a thing. In the fixing device 40, a contact portion where the fixing belt 45 and the pressure roll 46 come into contact becomes a fixing processing portion that performs a required fixing process (heating and pressing).

  The paper feeding device 50 is disposed so as to exist at a position below the intermediate transfer device 20 and the secondary transfer device 30. The paper feeding device 50 includes a plurality (or a single) of paper storage bodies 51 and 51 for storing recording paper 5 of a desired size and type, and the recording paper 5 from the paper storage body 51 one by one. It is mainly comprised by the sending-out apparatus 52 to send out. The paper container 51 is attached, for example, so that it can be pulled out to the front side (side surface on which the user faces during operation) of the first housing 1a.

  Between the paper feeding device 50 and the secondary transfer device 30, a plurality of paper conveyance roll pairs 53 and 54 for conveying the recording paper 5 delivered from the paper feeding device 50 to the secondary transfer position T2 and a conveyance guide material (not shown). Are provided. A pair of paper transporting rolls 54 disposed at a position immediately before the secondary transfer position T2 in the paper feed transporting path 56 is configured as a roll (registration roll) that adjusts the transporting timing of the recording paper 5, for example. At a middle position of the paper feed transport path 56, a paper feed transport path 57 that receives and transports the recording paper 5 supplied from a large-capacity paper feed device (not shown) disposed adjacent to the first housing 1a. Are joined. Further, between the secondary transfer device 30 and the fixing device 40, the recording paper 5 after the secondary transfer sent out from the secondary transfer device 30 is conveyed to the fixing device 40, and therefore in the illustrated example, a four-belt form is used. The sheet transport devices 58a to 58d such as are provided inside the second housing 1b.

  As an example of the conveying apparatus according to the first embodiment, the recording sheet 5 is cooled downstream of the fixing apparatus 40 by a sheet conveying apparatus 59 such as a belt form and the toner image is fixed by the fixing apparatus 40. A cooling device 70 is arranged. Further, on the downstream side of the cooling device 70, the curl correction device 80 that corrects the curl of the recording paper 5 by conveying the recording paper 5 sandwiched between a plurality of rolls and belts, and the recording paper A detection device 90 for detecting a toner density defect, an image defect, an image position defect, and the like of the toner image fixed to 5 is sequentially provided. The detection device 90 irradiates light onto the recording paper 5 from the light source, and reads reflected light reflected upward by the recording paper 5 with an image reading element such as a CCD image sensor, thereby causing toner density defects, image defects, and image positions. Detect defects and the like.

  Furthermore, in a portion near the paper discharge port formed in the second housing 1b, the paper discharge section 60 in which the recording paper 5 after passing through the detection device 90 is disposed outside the second housing 1b. A paper discharge path 62 having a paper discharge roll pair 61 for discharging the paper is provided. Below the pair of paper discharge rolls 61, a reverse path 63 is disposed that reverses and conveys the recording paper 5 when forming images on both sides of the recording paper 5. The reversing path 63 temporarily accommodates the double-sided conveyance path 64 that switches the conveyance direction of the recording sheet 5 downward, and the recording sheet 5 that is conveyed along the double-sided conveyance path 64, and changes the conveyance direction of the recording sheet 5. A reverse feed path 65 that feeds the paper to the paper feed conveyance path 56 is provided.

  In FIG. 1, reference numeral 101 denotes an image processing unit that performs image processing on image data sent from an external device such as a computer provided in the upper part of the second housing 1 b, and 102 denotes an operation of the image forming apparatus 1. A control unit 103 performs overall control, and a user interface unit 103 allows a user to operate the image forming apparatus 1.

<Basic operation of image forming apparatus>
Hereinafter, a basic image forming operation by the image forming apparatus 1 will be described.

  Here, first, a full-color image constituted by combining toner images of four colors (Y, M, C, K) using the four image forming devices 10 (Y, M, C, K). The image forming operation at the time of forming will be described as a representative.

  When the image forming apparatus 1 receives command information for requesting an image forming operation (printing), the four image forming apparatuses 10 (Y, M, C, K), the intermediate transfer apparatus 20, the secondary transfer apparatus 30, and the fixing apparatus. 40 etc. starts.

  In each image forming device 10 (Y, M, C, K), each photoconductor drum 11 is first rotated in the direction indicated by an arrow A, and each charging device 12 makes a required surface of each photoconductor drum 11 on the surface. Each is charged to a polarity (negative polarity in the first embodiment) and a potential. Subsequently, the exposure apparatus 13 converts the image information input to the image forming apparatus 1 into each color component (Y, M, C, K) with respect to the surface of the photosensitive drum 11 after charging. The light LB emitted based on this signal is irradiated, and an electrostatic latent image of each color component composed of a required potential difference is formed on the surface thereof.

  Subsequently, each developing device 14 (Y, M, C, K) has a corresponding color charged with a required polarity (minus polarity) with respect to the electrostatic latent image of each color component formed on the photosensitive drum 11. (Y, M, C, K) toners are respectively supplied and electrostatically adhered to perform development. By this development, the electrostatic latent images of the respective color components formed on the respective photosensitive drums 11 are visualized as toner images of four colors (Y, M, C, K) respectively developed with the corresponding color toners. It becomes.

  Subsequently, when the toner images of the respective colors formed on the photosensitive drums 11 of the respective image forming devices 10 (Y, M, C, K) are conveyed to the primary transfer position T1, the primary transfer device 15 causes the respective colors. Are transferred to the intermediate transfer belt 21 rotating in the direction indicated by the arrow B of the intermediate transfer device 20 in such a manner that the toner images are sequentially superimposed.

  Further, in each image forming device 10 for which the primary transfer has been completed, the drum cleaning device 16 removes the adhering material so as to scrape off and cleans the surface of the photosensitive drum 11. Finally, the static eliminator 17 performs the photosensitive operation after the cleaning. The surface of the body drum 11 is neutralized. Thereby, each image forming apparatus 10 is brought into a state in which the next image forming operation can be performed.

  Subsequently, in the intermediate transfer device 20, the toner image primarily transferred by the rotation of the intermediate transfer belt 21 is held and conveyed to the secondary transfer position T2. On the other hand, the paper feeding device 50 sends out the required recording paper 5 to the paper feeding conveyance paths 55 and 56 in accordance with the image forming operation. In the paper feeding / conveying path 56, a pair of paper conveying rolls 54 as resist rolls feeds the recording paper 5 to the secondary transfer position T2 in accordance with the transfer timing.

  At the secondary transfer position T2, the secondary transfer device 30 performs a secondary transfer of the toner image on the intermediate transfer belt 21 onto the recording paper 5 at once. Further, in the intermediate transfer device 20 that has finished the secondary transfer, the belt cleaning device 29 removes the adhering matter such as toner remaining on the surface of the intermediate transfer belt 21 after the secondary transfer, and cleans it.

  Subsequently, the recording paper 5 onto which the toner image has been secondarily transferred is peeled from the intermediate transfer belt 21 and the secondary transfer device 30 and then conveyed to the fixing device 40 by the conveying devices 58a to 58d. In the fixing device 40, necessary recording processing (heating and pressing) is performed by introducing and passing the recording paper 5 after the secondary transfer through a contact portion between the rotating fixing belt 45 and the pressure roll 46. Then, the unfixed toner image is fixed on the recording paper 5. The recording paper 5 after the fixing is finished is cooled by the cooling device 70, and the curvature (curl) is corrected and made flat by the correction device 80, and then an image defect or the like is detected by the detection device 90. When the image forming operation is performed only to form an image on the sheet, the sheet is discharged to the discharge container 60 disposed outside the second casing 1b by the sheet discharge roll pair 61 via the sheet discharge path 62, for example. The

  When forming images on both sides of the recording sheet 5, the recording sheet 5 is introduced into the reversing path 63 via the duplex conveying path 64, and the reversing paper feeding path 65 provided in the middle of the reversing path 63. Thus, the recording paper 5 passes through the paper feed conveyance path 56 and is conveyed again to the secondary transfer position T2 in the state where the traveling direction of the recording paper 5 is reversed (the front and back are reversed). Then, as described above, after the toner image is fixed by the fixing device 40, the recording paper 5 on which the image is transferred to the back surface at the secondary transfer position T2 is cooled by the cooling device 70, and the correction device 80 and the detection device are detected. The paper is discharged to the discharge container 60 by the paper discharge roll pair 61 through the device 90.

  Through the above operation, the recording paper 5 on which a full color image formed by combining four color toner images is output.

  Next, the operation when the image forming apparatus 1 forms a special color toner image composed of the developer of the special colors S1 and S2 when performing the normal image formation described above, for example, will be described.

  In this case, first, in the image forming apparatuses 10S1 and 10S2, the same image forming operation as that of the image forming apparatus 10 (Y, M, C, K) described above is performed. Special color toner images (S1, S2) are formed on the photosensitive drum 11, respectively. Subsequently, the special color toner images formed by the image forming devices 10S1 and 10S2 are primarily transferred to the intermediate transfer belt 21 of the intermediate transfer device 20 in the same manner as the image forming operation related to the four color toner images described above. After that, the secondary transfer device 30 performs secondary transfer from the intermediate transfer belt 21 to the recording paper 5 (along with toner images of other colors). Finally, the recording paper 5 on which the special color toner image and the toner image of the other color are secondarily transferred is subjected to the fixing process in the fixing device 40, and then passes through the required devices 70, 80, 90 to the second casing. It is discharged outside the body 1b.

  Through the above operation, the recording paper 5 formed so that the two special color toner images are overlapped on the entire surface or a part of the full color image formed by combining the above-described four color toner images is output. The

  The image forming apparatus 1 directly records toner images formed by the image forming apparatuses 10 (S1, S2, Y, M, C, and K) without using the intermediate transfer belt 21 of the intermediate transfer apparatus 20. It may be configured to transfer onto the paper 5. In this case, the image forming unit is configured to form an image by directly transferring a toner image formed by a single or a plurality of image forming apparatuses 10 onto a recording sheet.

<Configuration of cooling device>
FIG. 3 is a configuration diagram illustrating a cooling device as an example of a transport device according to the first embodiment.

  As shown in FIG. 3, the cooling device 70 roughly includes an upper unit 71 disposed above and a lower unit 72 disposed below. The upper unit 71 includes a first conveyor belt 73 as an example of an endless first belt that circulates and a heat sink (cooling member) as an example of a contact member disposed on the inner peripheral side of the first conveyor belt 73. 74). The lower unit 72 is arranged on the inner side of the second conveyor belt 75 as an example of an endless second belt that circulates and the second conveyor belt 75. A pressing roll 76 as an example of a pressing member that presses against the heat sink 74 with a single conveying belt 73 interposed therebetween.

  As the first conveying belt 73, for example, an endless belt made of a synthetic resin material such as polyimide is used. The first conveyance belt 73 is supported so as to circulate and move by a plurality of belt support rolls 731 to 735 in a state where a required tension is applied. Among the plurality of belt support rolls, the belt support roll 731 disposed close to the downstream side in the belt movement direction of the heat sink 74 is configured as a drive roll for circulating and moving the first transport belt 73, It is rotationally driven by a drive motor (not shown). The belt support rolls 732, 734, and 735 are configured as driven rolls that hold the travel position of the first conveyance belt 73, and the belt support roll 733 is a tension application roll that applies a required tension to the first conveyance belt 73. It is configured. The belt support rolls 731 to 735 are formed longer than the belt width of the first transport belt 73 along a direction (axial direction) intersecting the moving direction of the first transport belt 73. The belt support roll 733 may be configured as a steering roll that corrects the meandering of the first transport belt 73.

  Further, as shown in FIG. 4, the first conveying belt 73 is the maximum size recording sheet along the direction intersecting the moving direction of the belt among the recording sheets 5 on which the image is formed by the image forming apparatus 1. The width W2 is larger than the width W1 of five. Therefore, even if the recording paper 5 is the maximum size recording paper 5, the entire surface thereof is conveyed in a state of being in contact with the first conveying belt 73. In the figure, reference numeral C indicates a center line that is a conveyance reference of the recording paper 5.

  As shown in FIG. 3, the heat sink 74 as an example of a contact member disposed on the inner peripheral side of the first transport belt 73 so as to contact a part of the inner peripheral surface of the first transport belt 73. Is provided. The heat sink 74 is in contact with the inner peripheral surface of the first conveyor belt 73 in the stretched region between the drive roll 731 and the third driven roll 735. The drive roll 731 and the third driven roll 735 are disposed above the lower end surface of the heat sink 74, and the first transport belt 73 is disposed so as to contact the lower end surface of the heat sink 74 by its tension. The heat sink 74 is made of a material having a higher thermal conductivity than that of the first transport belt 73, and is made of, for example, a metal material such as aluminum. Of course, the heat sink 74 may be made of other materials. The heat sink 74 includes a substrate 741 in contact with the first transport belt 73 at the lower end thereof. The lower end surface 741a of the substrate 741 that is in contact with the first conveying belt 73 is formed in a curved shape having a large radius of curvature so as to be planar or convex downward. Further, the upstream and downstream ends of the substrate 741 along the belt moving direction have a curved shape with a small radius of curvature.

  The substrate 741 has a width equal to or greater than that of the first conveyor belt 71 along a direction intersecting with the moving direction of the first conveyor belt 73 (hereinafter referred to as “belt width direction”). doing. Further, the length of the substrate 741 along the moving direction of the first conveying belt 71 is set in consideration of the cooling efficiency of the recording paper 5. In this embodiment, the cooling device 70 is significantly reduced in size as compared with the conventional device, and the length of the substrate 741 along the belt moving direction is set to about 75 mm, for example.

  A thin heat sink 742 formed in a thin flat plate shape is disposed on the upper end surface of the substrate 741 along the width direction of the belt and is spaced apart from the substrate 741 along the belt movement direction. A plurality are arranged so as to contact each other. In addition, side plates 743 and 744 that partition a space in which the plurality of heat dissipation plates 742 are disposed are provided at upstream and downstream ends of the heat dissipation plates 742 in the belt moving direction. Further, a ceiling plate 745 is disposed at the upper end of the plurality of heat radiating plates 742 from the upstream side plate 743 to the downstream side plate 744. The heat sink 74 forms a closed space in which the bottom surface and the top surface of the plurality of heat radiating plates 742 and the upstream and downstream side surfaces are surrounded by the substrate 741, both side plates 743, 744 and the ceiling plate 745. Further, both side surfaces (the front side and the back side in the direction perpendicular to the drawing) of the heat sink 74 along the belt width direction are opened all over. The heat sink 74 constitutes one electrically connected conductor by constituting members such as the substrate 741 and the side plates 743 and 744 in contact with each other.

  The heat sink 74 includes a cooling fan 746 as a cooling means on the back side (the back side in the direction perpendicular to the drawing). The cooling fan 746 is rotationally driven when the cooling device 70 is operated, and discharges air sucked from the front side (the front side in the direction perpendicular to the drawing) of the image forming apparatus 1 to the back side (the back side in the direction perpendicular to the drawing). As a result, the air flow is brought into contact with each heat radiating plate 742 to radiate heat from each heat radiating plate 742. In this embodiment, the heat sink 74 is greatly reduced in size, and the cross-sectional shape of the heat sink 74 is set smaller than the outer diameter of the cooling fan 746.

  As the second conveyor belt 75, an endless belt made of a synthetic resin material such as polyimide is used, for example, as with the first conveyor belt 73. The second conveyor belt 75 is supported so as to circulate and move by a plurality of belt support rolls 751 to 754 while being stretched with a required tension. Among the plurality of belt support rolls, the belt support roll 751 is configured as a drive roll for circulating and moving the second transport belt 75, and is rotationally driven by a drive motor (not shown). The drive roll 751 is disposed so as to face the drive roll 731 of the first transport belt 73 and is in pressure contact with the drive roll 731. The belt support rolls 752 and 754 are configured as driven rolls that hold the travel position of the second transport belt 75, and the belt support roll 753 is configured as a tension applying roll that applies a required tension to the second transport belt 75. ing. The belt support rolls 751 to 754 are set so that the length along the direction (axial direction) intersecting the moving direction of the second transport belt 75 is longer than the width of the second transport belt 75.

  Further, as shown in FIG. 4, the second conveying belt 75 has a width larger than that of the maximum size recording sheet 5 along the belt width direction among the recording sheets 5 on which an image is formed by the image forming apparatus 1. W2.

  On the inner peripheral side of the second conveyor belt 75, the second conveyor belt 75 is connected to the end of the heat sink 74 where the first conveyor belt 73 starts to contact the heat sink 74. A pressing roll 76 as an example of a pressing member that presses against the heat sink 74 is disposed. In this embodiment, a pressing roll 76 is disposed at the upstream end of the heat sink 74 along the moving direction of the first conveyor belt 73.

  As shown in FIG. 4, for example, the pressing roll 76 is configured by covering an outer periphery of a metal cored bar 761 with an elastic body layer 762 having a required rubber hardness along the axial direction over a required thickness. Has been. The length of the elastic layer 762 of the pressing roll 76 along the axial direction is, for example, equal to or longer than the width of the maximum size recording paper 5 and the first and second conveying belts 73, The width is set to be shorter than 75.

  The pressing rolls 76 are pressed against the heat sink 74 with a required pressing load F by elastic members 763 made of compression springs or the like disposed at both ends of the core metal 761. The pressing member 76 is not limited to a rotating roll shape, and may be a fixed roll body, a film-like member, a pad-like member, or the like.

  In the first embodiment, as shown in FIG. 3, a charge is provided on an end portion side of the heat sink 74 that is provided in the heat sink 74 as an example of the contact member and the first conveying belt 73 starts to contact the heat sink 74. Is provided with a resistance R having a predetermined high resistance value as an example of a suppression means for suppressing the induction of.

  The heat sink 74 is insulated and attached to a supporting structure member such as a frame constituting the second casing 1b of the image forming apparatus 1 via an insulating member (not shown), and is in an electrically floating state. . Here, the floating state means that the heat sink 74 is not directly connected to the ground potential or a required power source, and the potential is independent.

As shown in FIG. 3, the heat sink 74 is connected to the ground via a resistor R having a relatively high resistance value of about 10 ⁷ to 10 ⁹ Ω, for example, about 200 MΩ (grounded). )

<Operation of cooling device>
Next, the operation of the cooling device of the image forming apparatus 1 will be described.

  In the cooling device 70, when the image forming apparatus 1 receives command information for requesting an image forming operation (printing), the first conveying belt 73, the second conveying belt 75, and the cooling fan 746 are started.

  As shown in FIG. 1, the recording paper 5 on which the toner image of each color is fixed by heating and pressing by the fixing device 40 is conveyed to the cooling device 70 by a conveying device 59 such as a belt form. In the cooling device 70, as shown in FIG. 3, the first and second conveyor belts 73, 73, with the recording paper 5 being conveyed sandwiched between the first conveyor belt 73 and the second conveyor belt 75, It is conveyed downstream along the moving direction of 75.

  Meanwhile, the recording paper 5 is sandwiched between the first and second transport belts 73 and 75 by the pressing roll 76 disposed on the inner peripheral side of the second transport belt 75, and the first transport belt 73. And pressed against the surface 741a of the heat sink 74. The heat of the recording paper 5 and the toner image fixed on the surface thereof is transferred to the heat sink 74 through the first conveying belt 73 by heat conduction, and the recording paper 5 and the toner image are cooled.

  The heat transmitted to the heat sink 74 is released into the air from the heat radiating plate 742 by the air flowing so as to pass between the heat radiating plates 742 by operating the cooling fan 746, and the heat sink 74 is cooled.

  Incidentally, as shown in FIG. 1, the recording paper 5 fixed by the fixing device 40 is subjected to the secondary transfer after the toner images on the intermediate transfer belt 21 are collectively transferred at the secondary transfer position T2, as shown in FIG. The sheet is separated from the sheet, and is subjected to a fixing process by the fixing device 40 and is conveyed to the cooling device 70 by the sheet conveying device 59. At that time, as shown in FIG. 5, the recording paper 5 holds a toner image charged to a negative polarity, and the toner supplied to the support roll 26 of the secondary transfer device 30 or the intermediate transfer device 20. The surface is charged with a negative polarity that is the same polarity as the charging polarity of the toner, and is charged by a DC voltage having the opposite polarity or the same polarity as the charging polarity. In particular, when a full-color image or the like is formed on the recording paper 5, the amount of toner image transferred onto the recording paper 5 is relatively large compared to a monochrome image, and the negative polarity of the recording paper 5 is present. There is also a tendency that the amount of charge increases.

  Therefore, in the conventional cooling device 70, as shown in FIG. 5A, the recording paper 5 charged to a negative polarity passes through the heat sink 74 while being sandwiched between the first and second transport belts 73 and 75. In this case, the surface 741a of the heat sink 74 on the first conveyance belt 73 side, in particular, the end where the first conveyance belt 73 starts to contact the heat sink 74 due to the electrostatic induction effect due to the negative polarity charge of the recording paper 5. On the side, a positive charge having a polarity opposite to the charged polarity of the recording paper 5 is drawn through a grounded frame (not shown).

  As described above, in the conventional cooling device 70, when a positive charge having a polarity opposite to the charging polarity of the recording paper 5 is attracted to the surface of the heat sink 74 on the side of the first conveying belt 73, the first and second conveying belts. A relatively large electrostatic attraction force (Coulomb force) acts between the recording sheet 5 conveyed by 73 and 75 and the heat sink 74. Therefore, the recording paper 5 is attracted to the heat sink 74 via the first conveyance belt 73, and the adhesion force between the first conveyance belt 73 and the heat sink 74 is increased, so that the conveyance load of the first conveyance belt 73 is increased. To do.

  Therefore, in the first embodiment, as shown in FIG. 3 and FIG. 5B, the recording sheet charged to a negative polarity by connecting the heat sink 74 to the ground potential via a high resistance R of about 200 MΩ. 5 is prevented from being induced to the heat sink 74 via the ground potential when the belt 5 is transported by the first and second transport belts 73 and 75. Therefore, the electrostatic adsorption force (Coulomb force) acting between the recording paper 5 conveyed by the first and second conveyance belts 73 and 75 and the heat sink 74 can be reduced, and the first conveyance belt 73 is achieved. It is possible to suppress an increase in the conveyance load of the first conveyance belt 73 due to an increase in the adhesion force between the heat sink 74 and the heat sink 74.

[Embodiment 2]
FIG. 6 shows a cooling device as an example of a transport device according to the second embodiment.

  As shown in FIG. 6, in the cooling device 70, the suppression unit is configured by a unit that holds a heat sink 74 as an example of a contact member in an electrically floating state. In the second embodiment, the heat sink 74 is not connected to the ground potential via the high resistance R, but the heat sink 74 is in an insulated state, and the heat sink 74 is insulated from the second casing 1b of the image forming apparatus 1 (not shown). By being mounted via a member, it is configured to be held in an electrically floating state.

  In the second embodiment, the high resistance R is not required as compared with the first embodiment, so that the number of parts can be reduced. However, the heat sink 74 needs to be kept in an insulating state so as to prevent the inflow of charges from a supporting component such as a frame constituting the second casing 1a of the image forming apparatus 1.

[Embodiment 3]
FIG. 7 shows a cooling device as an example of a transport device according to the third embodiment.

  As shown in FIG. 7, the cooling device 70 is configured such that the restraining means is composed of an insulating member or a predetermined high resistance member interposed between the heat sink 74 and the first transport belt 73. is there.

More specifically, the cooling device 70 is provided with a thin sheet made of an insulating material on the surface of the end portion side of the heat sink 74 where the first conveying belt 73 starts to contact by means of adhesion or the like, or made of an insulating material. An antistatic member 77 formed by coating is provided. As a thin sheet made of an insulating member or a coating made of an insulating member, for example, a sheet or coating made of polyimide, PTFE (polytetrafluoroethylene) or the like and having a thickness of about 10 to 100 μm is used. The volume resistivity of the polyimide resin is about 10 ¹⁵ to 10 ¹⁷ (Ω · cm), and the volume resistivity of PTFE (polytetrafluoroethylene) is 10 ¹⁸ (Ω · cm) or more, both of which are very high. It is an insulating material having a high resistance value. Moreover, as a predetermined high resistance member, the member which has a high resistance value comparable as Embodiment 1 is mentioned.

  The charging suppression member 77 has a predetermined length on the end side (inlet side) where the first conveyor belt 73 starts to contact the heat sink 74 out of the lower end surface where the heat sink 74 contacts the first conveyor belt 73. By disposing over, a larger charge suppressing effect can be obtained.

  In the third embodiment, when the length of the heat sink 74 along the belt movement direction of the substrate 741 is about 75 mm, the heat sink 74 is located on the end side where the heat sink 74 starts to contact the first conveying belt 73. By providing the charge suppression member over a length of 10 to 20 mm, which is about 1/4 to 1/8 of the total length, a sufficient charge suppression effect can be obtained.

[Embodiment 4]
FIG. 8 shows a cooling device as an example of a transport device according to the fourth embodiment.

  In the fourth embodiment, as shown in FIG. 8, in addition to the above configuration, the pressing force that the pressing roll 76 partially reduces the pressing force that presses the second conveying belt 75 against the heat sink 74. The groove portions 747 and 748 as the reduction portions are provided along the direction (axial direction) in which the pressing roll 76 is arranged in correspondence with the position of the pressing roll 76.

  More specifically, the pressing force of the pressing roll 76 is applied to the surface (lower surface) 741a of the substrate 741 of the heat sink 74 as shown in FIG. Groove portions 747 and 748 as an example of a pressing force reducing portion to be partially reduced are provided at both end portions along the axial direction of the pressing roll 76. Further, the groove portions 747 and 748 are disposed at positions symmetrical with respect to the center line C passing through the center along the width direction of the first transport belt 73. The grooves 747 and 748 are formed in a rectangular shape having a required width W3 along the axial direction of the pressing roll 76 and a required length L along the belt moving direction. Further, the groove portions 747 and 748 may not be in contact with the elastic body layer 762 of the pressing roll 76 and may be able to partially reduce the pressing force that presses the pressing roll 76 against the heat sink 74. The depth D is set to about 1 mm, for example.

  Further, the elastic member 763 that applies a pressing force that presses the pressing roll 76 against the heat sink 74 has a pressing load F that is equal to the width W3 of the two grooves 747 and 748 provided on the substrate 741 of the heat sink 74. It is set smaller by an amount corresponding to the total length (twice W3). That is, the pressing roll 76 acts on the surface of the heat sink 74 as it is as the load F applied by the elastic member 761 on both ends thereof. Assuming that the load F acting on the pressing roll 76 is constant, the pressing force per unit length of the pressing roll 76 acting on the surface of the heat sink 74 is a groove portion as compared with the case where the groove portions 747 and 748 are not provided. The case where 747 and 748 are provided becomes larger.

  Therefore, in the fourth embodiment, the load F of the elastic member 761 that applies the pressing force that presses the pressing roll 76 toward the heat sink 74 is set to be small by the amount of the grooves 746 and 747 provided. Now, when the total length of the grooves 746 and 747 along the axial direction of the pressing roll 76 is ½ of the total length of the elastic layer 762 of the pressing roll 76, the load F of the elastic member 763 is set to the groove. 747 and 748 are set to ½ of the case where they are not provided. Note that the load F of the elastic member 763 may be set similarly to the case where the grooves 747 and 748 are not provided.

<Operation of cooling device>
Next, the operation of the cooling device of the image forming apparatus 1 according to the fourth embodiment will be described.

  In the cooling device 70, when the image forming apparatus 1 receives command information for requesting an image forming operation (printing), the first conveying belt 73, the second conveying belt 75, and the cooling fan 746 are started.

  As shown in FIG. 1, the recording paper 5 on which the toner image of each color is fixed by being heated and pressed by the fixing device 40 is conveyed to the cooling device 70 by a conveying device 59 such as a belt form. In the cooling device 70, the recording sheet 5 being conveyed is sandwiched between the first conveyance belt 73 and the second conveyance belt 75, and the downstream along the moving direction of the first and second conveyance belts 73 and 75. To the side.

  Incidentally, in the heat sink 74 according to the fourth embodiment, as shown in FIG. 8, grooves 747 and 748 are respectively provided at positions corresponding to both end portions along the axial direction of the pressing roll 76. Therefore, even when the recording paper 5 having a residual charge is introduced into the cooling device 70, the space between the surface of the heat sink 74 and the first conveying belt 73 is as shown in FIG. 9B. Since the gap is generated in the region where the groove portions 747 and 748 are provided, it is possible to further suppress the electrostatic attraction force acting between the surface of the heat sink 74 and the recording paper 5, and the first The conveyance load of the conveyance belt 73 is reduced.

  Further, the pressing load F of the elastic member 763 that presses the pressing roll 76 against the heat sink 74 is set to be smaller than that in the case where the groove portions 747 and 748 are not provided. Therefore, in a state where the recording paper 5 is sandwiched between the first and second transport belts 73 and 75, the first and second transport belts 73 and 75 are pressed by the pressing roll 76 from the inner peripheral side of the second transport belt 75. When the recording paper 5 is pressed against the heat sink 74, the pressing force exerted by the pressing roll 76 on the heat sink 74 is reduced.

  The frictional resistance including electrostatic attraction acting between the first conveying belt 73 and the surface 741a of the heat sink 74 depends on the distance between the recording paper 5 and the heat sink surface 741a, and the pressing force of the pressing roll 76. Therefore, the pressing force of the pressing roll 76 decreases as the pressing force decreases. Therefore, it is possible to reduce the transport load when transporting the first transport belt 73 so as to circulate. Therefore, it is possible to reduce the size of the drive motor that drives the first conveyor belt 73 and to reduce the drive current. Further, by reducing the transport load of the first transport belt 73, the transport load of the second transport belt 75 that is in pressure contact with the first transport belt 73 directly or via the recording paper 5 can also be reduced. . As a result, it is possible to reduce the size of the drive motor that drives the second conveyor belt 75 and to reduce the drive current.

  The recording paper 5 conveyed to the cooling device 70 is pressed from the inner peripheral side of the second conveyance belt 75 while being sandwiched between the first conveyance belt 73 and the second conveyance belt 75. Since it is pressed against the heat sink 74 by 76, the first and second conveyor belts 73 and 75 can be reliably and stably conveyed.

[Embodiment 5]
FIG. 10 is a block diagram showing a cooling device as an example of a transport device according to Embodiment 5 of the present invention.

  In the fifth embodiment, as shown in FIG. 10, grooves 747 and 748 are provided on the surface 741a of the substrate 741 of the heat sink 74 as in the fourth embodiment.

  In the fifth embodiment, the length W3 along the axial direction of the elastic body layer 762 of the pressing roll 76 is set to be shorter than that of the fourth embodiment by about 1/3. Yes. In the pressing roll 76, the portion of the cored bar 761 in which the elastic body layer 762 is not provided constitutes a pressing force reducing unit. The elastic body layer 762 is located on the inner side of the groove portions 747 and 748 of the heat sink 74, and is disposed at the center portion along the axial direction of the pressing roll 76.

  Further, in the fifth embodiment, the load F of the elastic member 763 that applies the pressing force that presses the pressing roll 76 toward the heat sink 74 is applied along the axial direction of the elastic body layer 762 of the pressing roll 76. Depending on the length, the elastic layer 762 is set to about ３ as compared with the case where the elastic layer 762 is provided over the entire width W1 of the maximum size recording paper 5.

  As described above, in the fifth embodiment, the length along the axial direction of the elastic body layer 762 pressed against the heat sink 74 of the pressing roll 76 is set to be shorter than the case where the entire length of the recording paper 5 is provided. By doing so, it is possible to avoid that the recording paper 5 and the surface 741 of the heat sink 74 are close to each other in the area other than the elastic body layer 762 of the pressing roll 76 in addition to the area of the groove portions 747 and 748. 5 and the electrostatic attraction force acting between the heat sink surface 741 can be reduced. Therefore, the load with which the pressing roll 76 is pressed against the heat sink 74 can be reduced, and the conveyance load of the first and second conveyance belts 73 and 75 can be reduced.

  In the fifth embodiment, it is only necessary to set the length of the elastic layer 762 of the pressing roll 76 along the axial direction to be short, and the configuration of the pressing roll 76 can be simplified.

[Embodiment 6]
FIG. 11 is a block diagram showing a cooling device as a transport device according to Embodiment 6 of the present invention.

  In the sixth embodiment, as shown in FIG. 11, the elastic body layer 762 of the pressing roll 76 is divided into two along the axial direction, and the two elastic body layers 762 are combined in the axial direction. The length is set to be about ½ of the elastic layer 762 of the pressing roll 76 according to the fourth embodiment. The interval between the two elastic layers 762 is set to be smaller than the width of the recording paper 5 having a minimum length along the width direction of the belt.

  In the sixth embodiment, the load F of the elastic member 763 that applies a pressing force that presses the pressing roll 76 against the heat sink 74 is a length along the axial direction of the elastic layer 762 of the pressing roll 76. Accordingly, the elastic layer 762 is set to about ½ compared with the case where the elastic layer 762 is provided over the entire length along the axial direction. The substrate 741 of the heat sink 74 is not provided with the groove portions 747 and 748.

  As described above, in the sixth embodiment, the length along the axial direction of the elastic body layer 762 pressed against the heat sink 74 of the pressing roll 76 is set to be shorter than the case where the entire length of the recording paper 5 is provided. By doing so, it is possible to avoid the recording paper 5 and the surface 741 of the heat sink 74 from approaching each other, and it is possible to reduce the electrostatic attractive force acting between the recording paper 5 and the heat sink surface 741. . Therefore, it is possible to reduce the conveyance load of the first and second conveyance belts 73 and 75.

  Further, in the sixth embodiment, the elastic layer 762 of the pressing roll 76 is disposed at both end portions along the axial direction, so even the recording paper 5 having a large size along the belt width direction can be used. The two elastic layers 762 of the pressing roll 76 can apply a pressing force to both ends thereof, and can be reliably conveyed.

  FIG. 12 is a configuration diagram showing a modification of the cooling device according to the sixth embodiment.

  In the modification of the sixth embodiment, the elastic body layer 762 of the pressing roll 76 is not provided separately at both end portions along the axial direction, but is provided at the central portion along the axial direction of the pressing roll 76. Only one elastic body layer 762 having a relatively short length is arranged. Further, the load F of the elastic member 761 that applies a pressing force that presses the pressing roll 76 against the heat sink 74 is set in consideration of the length along the axial direction of the elastic layer 762 of the pressing roll 76. ing.

  From the viewpoint of reducing the transport load of the first transport belt 73, it is desirable that the length of the elastic layer 762 along the axial direction is shorter. The length of the elastic body layer 762 along the axial direction is set to, for example, about ¼ to ロ ー ル with respect to the pressing roll 76 according to the first embodiment.

[Embodiment 7]
FIG. 13 is a block diagram showing a cooling device for a transfer apparatus according to Embodiment 7 of the present invention.

  In the cooling device 70 as an example of the transfer device, the heat sink 74 is formed larger than that in the first embodiment or the like. Accordingly, the circumferences of the first and second conveyor belts 73 and 75 are also set longer than in the first embodiment.

In the seventh embodiment, a plurality ( _{four in the} illustrated example) of pressing rollers 76 _{1 to} 764 disposed on the inner peripheral side of the second conveying belt 75 are provided. The elastic member ₇₆₃ 1-763 ₄ exerting a pressing force for pressing towards the pressing roller ₇₆ 1-76 ₄ to the heat sink 74, the elastic member 763 ₁ is other resilient member 763 ₂ which is located on the most upstream side ～763 compared to ₄ are set so that the load becomes smaller.

Incidentally, the most pressing roll 76 ₁ located on the upstream side may be similarly formed as pressing roll 76 shown its shape any form 4 to 6 of the embodiment.

Thus, in the seventh embodiment, among the plurality of pressing rolls 76 _{1-76 4} disposed on the inner peripheral side of the second conveyor belt 75, a pressing roller 76 ₁ located on the most upstream side heat sink Having set the load of the elastic member 763 ₁ is pressed against the 74 so as to be smaller as compared to the other pressing roll ₇₆₃ 2-763 ₄ to avoid the surface 741a of the recording sheet 5 and the heat sink 74 is adjacent It is possible to reduce the electrostatic attractive force acting between the recording paper 5 and the surface 741a of the heat sink 74. Therefore, it is possible to reduce the transport load applied to the first and second transport belts 73 and 75.

According to the study by the present inventors, when a plurality of pressing rolls 76 that press the second conveyor belt 75 against the heat sink 74 are disposed along the moving direction of the second conveyor belt 75, FIG. As shown in FIG. 15, it is known that the conveying load of the pressing roll 76 located on the most upstream side along the moving direction of the belt is the largest. Therefore, the most upstream side position of the pressing roll 761 and pressing load of other by setting to be smaller as compared with the pressing roller 76 _{1-76 4} of the first and second conveying belt 73, 75 It is possible to reduce the transport load applied to.

Incidentally, 14 and 15, a first current of a driving motor for driving the conveyor belt 73 when pressed against the heat sink 74 a plurality of pressing rolls 76 _{1-76 4} by the same load, pressing rolls 76 by changing the number of ₁ to 76 ₄ is measured by.

[Embodiment 8]
FIG. 16 is a block diagram showing an embodiment in which a conveying apparatus according to Embodiment 8 of the present invention is applied to a fixing apparatus.

  The fixing device 40 as an example of the conveying device includes a heating belt 45 as a heating unit. The heating belt 45 is stretched so as to circulate over the internal heating roll 451 that also serves as a driving roll, the external heating roll 452, the driven rolls 453 to 455, and the fixed pad 456. The fixed pad 456 is composed of a metal block. Further, a pressurizing belt 46 is provided as the pressurizing means. The pressure belt 46 is stretched between driven rolls 461 to 463, a pressing roll 464, and a pressure pad 465. The pressure belt 46 is configured to rotate following the heating belt 45.

  In the eighth embodiment, the pressing roll 464 is configured in the same manner as the pressing roll 76 in the fourth to seventh embodiments.

  Therefore, also in the eighth embodiment, the conveyance load of the heating belt 45 can be reduced.

  In the above embodiment, the case where the grooves 747 and 748 are provided on the surface of the substrate 741 of the heat sink 74 has been described. However, the present invention is not limited to this, and the substrate 741 made of a metal such as aluminum of the heat sink 74 is not limited thereto. 17 is manufactured by drawing or the like, and by controlling the drawing speed or the like, the surface 741a of the substrate 741 of the heat sink 74 along the direction intersecting the belt moving direction as shown in FIG. A minute (about 50 μm) wave-shaped unevenness may be formed.

70 ... Cooling device 73 ... First conveyor belt 74 ... Heat sink 75 ... Second conveyor belt 76 ... Pushing member R ... High resistance

Claims (7)

An endless first belt that circulates;
An endless second belt that is disposed on the outer peripheral side of the first belt, circulates and moves with the conveyed member sandwiched between the first belt, and conveys the conveyed member;
A contact member disposed on the inner peripheral side of the first belt and in contact with the transported member transported by the second belt via the first belt;
Suppression means for suppressing charge induction on the end side of the contact member where the first belt starts contact;
A transport apparatus comprising:   The transport device according to claim 1, wherein the suppressing unit includes a unit that grounds the contact member through a predetermined high resistance or places the contact member in an electrically floating state.   The transport device according to claim 1, wherein the suppressing unit is formed of a predetermined high resistance member or an insulating member interposed between the contact member and the first belt.   4. A pressing member that is disposed on an inner peripheral side of the second belt and that presses the second belt against an end side of the contact member where the first belt starts to contact the contact member. The conveying apparatus in any one of.   5. The pressing force reducing unit that partially reduces a pressing force with which the pressing member presses the second belt against the contact member at least one of the pressing member and the contact member. Transport device.   The cooling device as a transport device according to claim 1, wherein the contact member includes a cooling member that cools the transported member via the first belt. An image forming unit for forming an image on a recording medium;
Fixing means for fixing by heating a recording medium on which an image is formed by the image forming unit;
The image forming apparatus comprising the cooling device according to claim 6, wherein the recording medium on which the image is fixed by the fixing unit is cooled as the transported member.

Images