JP2015106021A - Conveyance device, cooling device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conveyance device capable of reducing the conveyance load of a belt circularly moved in contact with a contact member, to convey a member to be conveyed.SOLUTION: A recording paper 5 is cooled by a heat sink 74 arranged on the inner peripheral side of a first conveyance belt 73, while the recording paper 5 after fixation processing is performed is conveyed by the first conveyance belt 73 and a second conveyance belt 75 in a state of being held between the first conveyance belt 73 and the second conveyance belt 75. The second conveyance belt 75 is pressed to an end side on the side of the heat sink 74 where the first conveyance belt 73 starts to contact with the heat sink 75 by a pressing roll 76 arranged on the inner peripheral side of the second conveyance belt 75. In the heat sink 74, groove parts 747 and 748 for partially reducing a pressing force for allowing the pressing roll 76 to press the second conveyance belt 75 to the heat sink 74 are provided, so that the conveyance load of the first conveyance belt 73 circularly moved in contact with the heat sink 74 is reduced.

Description

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

  As technologies related to the transport device, those disclosed in Patent Documents 1 to 3 have already been proposed. 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 is configured to include 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 3 is configured such 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 2013-109028 A JP 2013-1114094 A

  The problem to be solved by the present invention is to reduce the conveyance load of the belt that conveys the member to be conveyed by circulating and moving while contacting the contact member.

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;
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;
With
At least one of the pressing member and the contact member is provided with a pressing force reducing unit that partially reduces a pressing force with which the pressing member presses the second belt against the contact member. It is a conveying device.

  According to a second aspect of the present invention, the pushing force reducing portion is provided on a surface of the contact member, and is configured by a groove portion that makes a part of the pushing member non-contact with the contact member. It is a conveying apparatus of Claim 1 characterized by the above-mentioned.

  The invention described in claim 3 is characterized in that the pressing force reducing portion is formed of a concave portion provided in a part of the pressing member and brought into a non-contact state with the contact member. Item 3. The transfer device according to Item 1 or 2.

  According to a fourth aspect of the present invention, the pressing force reducing portion is disposed on the inner side of the maximum dimension of the transported member along a direction intersecting the moving direction of the first and second belts. It is a conveyance apparatus in any one of the Claims 1 thru | or 3 characterized by the above-mentioned.

  According to a fifth aspect of the present invention, in the pressing member, a pressing load for pressing the pressing member against the contact member is set to be small according to a region where the pressing force reducing portion is provided. It is a conveyance apparatus in any one of the Claims 1 thru | or 4 characterized by the above-mentioned.

  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, as compared with a configuration that does not include the pressing force reducing unit, the conveyance load of the belt that conveys the member to be conveyed is reduced by circulating and moving while being in contact with the contact member. be able to.

  According to the second aspect of the present invention, the member to be transported can be moved by circulating while contacting the contact member without changing the structure of the pressing member as compared with the case where the structure of the invention is not provided. The conveyance load of the belt to convey can be reduced.

  According to the invention described in claim 3, compared with the case where the configuration of the invention is not provided, the transport load of the belt that transports the transported member by circulating and moving in contact with the contact member with a simple configuration is reduced. Can be reduced.

  According to the invention described in claim 4, compared with the case where the configuration of the invention is not provided, the belt conveyance load is reduced regardless of the dimension of the member to be conveyed along the direction intersecting the belt movement direction. be able to.

  According to the fifth aspect of the present invention, the belt conveyance load can be reduced as compared with the case where the pressing load for pressing the pressing member against the contact member is not set small.

  According to the invention described in claim 6, it is possible to reduce the conveying load of the belt that conveys the member to be conveyed by circulating and moving in contact with the cooling member as compared with the case where the configuration of the invention is not provided. it can.

  According to the seventh aspect of the present invention, as compared with the case where the cooling device according to the sixth aspect is not provided, the recording medium can be circulated while being in contact with the cooling member while maintaining the cooling performance of the recording medium. Thus, it is possible to reduce the transport load of the belt that transports the transported member.

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. 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. It is a schematic block diagram which shows the modification of the cooling device as a conveying apparatus which concerns on Embodiment 3 of this invention. It is a schematic block diagram which shows the cooling device as a conveying apparatus which concerns on Embodiment 4 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 5 of this invention. It is a block diagram which shows the electrostatic attraction force which arises between a recording paper and the surface of a heat sink. 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.

  1 and 2 show an image forming apparatus to which the conveying apparatus according to the first embodiment is 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. The six image forming devices 10 (S1, S2, Y, M, C, and 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 color toners and having a different saturation, a transparent toner for improving gloss, a foaming toner for Braille, a 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.

  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 configured by a delivery member such as a screw auger (not shown) that conveys the adhering matter to collect it and send it to a collection system (not shown). 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 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 and support the belt 21 in a freely circulating manner, and an outer peripheral surface (image holding surface) side of the intermediate transfer belt 21 supported by the belt support roll 26 And a secondary transfer device 30 that secondary-transfers the toner image on the intermediate transfer belt 21 to the recording paper 5 and remains on the outer peripheral surface of the intermediate transfer belt 21 after passing through the secondary transfer device 30. The belt cleaning device 29 mainly removes the adhering matter such as toner and paper dust and cleans it.

  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 as a secondary transfer voltage to the secondary transfer roll 30 or the support roll 26 of the intermediate transfer device 20.

  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, since the recording paper 5 after the secondary transfer fed from the secondary transfer roll 30 is conveyed to the fixing device 40 between the secondary transfer device 30 and the fixing device 40, in the illustrated example, a quadruple belt configuration is used. The sheet transport devices 58a to 58d such as are provided inside the second housing 1b.

  On the downstream side of the fixing device 40, a cooling device 70 is disposed as an example of a conveying device that cools the recording paper 5 on which the toner image is fixed by the fixing device 40 via a paper conveying device 59 such as a belt shape. . Further, on the downstream side of the cooling device 70, the recording paper 5 is conveyed while being sandwiched by a plurality of rolls, belts, and the like, thereby correcting the curving of the recording paper 5, and the recording paper 5 A detection device 90 is sequentially provided for detecting a toner density defect, an image defect, an image position defect, and the like of the toner image fixed on the toner image. 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 reverses and feeds paper to the paper feed conveyance path 53 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 T <b> 2, the secondary transfer roll 30 performs 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 sheet 5 on which the toner image is secondarily transferred is peeled off from the intermediate transfer belt 21 and the secondary transfer roll 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 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 a 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.

<Configuration of cooling device>
FIG. 3 is a block diagram showing a cooling device of the image forming apparatus 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 a first belt that circulates and a heat sink (cooling member) 74 as an example of a contact member disposed on the inner peripheral side of the first conveyor belt 73. have. The lower unit 72 is disposed on the inner side of the second conveyor belt 75 as an example of the second belt that circulates and moves on the inner periphery side of 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 belt 73 interposed therebetween is provided.

  As the first conveying belt 73, for example, an endless belt made of a synthetic resin material such as polyimide is used. The first conveyor 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 width of the first conveyor belt 73 along the direction (axial direction) intersecting the moving direction of the first conveyor 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.

  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 so as to be 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 come into contact with 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 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 dissipate 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 73, 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. 4A, the pressing roll 76 covers, for example, an elastic body layer 762 having a required rubber hardness on the outer periphery of a metal core bar 761 along the axial direction over a required thickness. Configured. 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. 4, groove portions 747 serving as pressing force reducing portions that partially reduce the pressing force by which the pressing roll 76 presses the second conveyor belt 75 against the heat sink 74. 748 is provided corresponding to the position of the pressing roll 76 along the direction (axial direction) in which the pressing roll 76 is disposed.

  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 this embodiment, the load F of the elastic member 761 that applies a 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 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. 3, 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.

  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. 12A, the recording paper 5 fixed by the fixing device 40 remains affected by the charge before fixing due to the charge of the toner itself and the charge added at the time of transfer. . Further, the recording paper 5 has a residual charge due to the influence of the peeling discharge when the pressure roll 46 in pressure contact with the fixing belt 45 has a nonconductive surface before and after passing through the nip portion of the fixing device 40. There is a case. Furthermore, the recording paper 5 is generated when the back surface resistance of the fixing belt 45 is increased and a sheet having a conductive surface is used as the pressure roll 46 in order to suppress the occurrence of streak image defects due to peeling discharge. In some cases, residual electric charges may still be present due to the influence of the discharge due to the potential difference with the exfoliation discharge portion being enlarged.

  As described above, when the recording paper 5 having a residual charge is introduced into the cooling device 70, electrostatic induction between the recording paper 5 and the heat sink 74 is caused by electrostatic induction from the heat sink 74 due to the residual charge of the recording paper 5. An attractive suction force acts, and the frictional resistance between the first conveyor belt 73 and the surface of the heat sink 74 increases. Therefore, there is a possibility that the conveyance load of the first conveyance belt 73 increases.

  Therefore, as shown in FIG. 4, the heat sink 74 is provided with grooves 747 and 748 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. Since the gap is generated in the region where the groove portions 747 and 748 are provided, it is possible to suppress the electrostatic attraction force from acting between the surface of the heat sink 74 and the recording paper 5, and the first conveying belt. It becomes possible to reduce the conveyance load of 73.

  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 2
FIG. 5 is a block diagram showing a cooling device as a transport device according to Embodiment 2 of the present invention.

  In the second embodiment, as shown in FIG. 5, grooves 747 and 748 are provided on the surface 741a of the substrate 741 of the heat sink 74 as in the first embodiment.

  Further, in the second embodiment, the length L2 along the axial direction of the elastic body layer 762 of the pressing roll 76 is set to be shorter than that of the first embodiment to 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 second embodiment, the load F of the elastic member 763 that applies a pressing force that presses the pressing roll 76 toward the heat sink 74 is applied along the axial direction of the elastic 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 recording paper 5 of the maximum size.

  As described above, in the second 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 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.

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

Embodiment 3
FIG. 6 is a block diagram showing a cooling device as a transport device according to Embodiment 3 of the present invention.

  In the third embodiment, as shown in FIG. 3, the elastic body layer 762 of the pressing roll 76 is divided into two along the axial direction, and the axial direction of the two elastic body layers 762 is combined. The length is set to be about ½ of the elastic layer 762 of the pressing roll 76 according to the first 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 third 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 third embodiment, the length along the axial direction of the elastic 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.

  In the third embodiment, since the elastic body layers 762 of the pressing rolls 76 are disposed at both ends along the axial direction, 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. 7 is a configuration diagram showing a modification of the cooling device according to the third embodiment.

  In the modification of the third embodiment, the elastic body layer 762 of the pressing roll 76 is not provided separately at both end portions along the axial direction, but 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 4
FIG. 8 is a block diagram showing a cooling device for a transfer apparatus according to Embodiment 4 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. Accordingly, the circumferences of the first and second conveyor belts 73 and 75 are also set longer than in the first embodiment.

In the fourth embodiment, a plurality ( _{four in the} illustrated example) of pressing rolls 76 _{1 to} 76 ₄ 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 in any of the first to third embodiments.

Thus, in the fourth 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 roller 76 _{2-76 4,} to avoid the surface 741 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 heat sink surface 741. Therefore, it is possible to reduce the transport load applied to the first and second transport belts 73 and 75.

According to the studies by the present inventors, when a plurality of pressing rolls 76 that press the second conveyor belt 75 against the heat sink 74 are arranged along the moving direction of the second conveyor belt 75, FIG. As shown in FIG. 10, it is known that the conveying load of the pressing roll 76 located on the most upstream side along the belt moving direction is the largest. Therefore, the first and second conveyor belt 73 by setting to the pressing load of the pressing roller 76 ₁ located on the most upstream side is reduced as compared to the other pressing roller 76 _{1-76 4,} The conveyance load given to 75 can be reduced.
9 and 10 show the current of the driving motor that drives the first conveyor belt 73 when the plurality of pressing rolls 76 _{1 to} 76 ₄ are pressed against the heat sink 74 with the same load. It is measured by changing the number of 76 _{1 to} 76 ₄ .

Embodiment 5
FIG. 11 is a block diagram showing a fixing device as a transport device according to Embodiment 5 of the present invention.

  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 drive roll, the external heating roll 452, the driven rolls 453 to 435, and the fixed pad 436. The fixed pad 436 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 fifth embodiment, the pressing roll 464 is configured similarly to the pressing roll 76 of the first to third embodiments.

  Therefore, also in the fifth 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. 13 is manufactured by drawing, etc., by controlling the drawing speed, etc., as shown in FIG. 13, the surface of the substrate 741 of the heat sink 74 has a minute amount along the direction intersecting the belt moving direction. You may comprise so that a corrugated unevenness | corrugation of about (about 50 micrometers) may be formed.

70 ... Cooling device 73 ... First transport belt 74 ... Heat sink 75 ... Second transport belt 76 ... Pushing member

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;
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;
With
At least one of the pressing member and the contact member is provided with a pressing force reducing unit that partially reduces a pressing force with which the pressing member presses the second belt against the contact member. Conveying device to do.   The said pressing force reduction part is provided in the surface of the said contact member, and is comprised from the groove part which makes a part of said pressing member a non-contact state with the said contact member. Transport device.   The conveying device according to claim 1, wherein the pressing force reducing unit is configured by a concave portion that is provided in a part of the pressing member and is in a non-contact state with the contact member.   The pressing force reducing portion is disposed inside a maximum dimension of the transported member along a direction intersecting a moving direction of the first and second belts. The conveying apparatus in any one of.   2. The pressing member according to claim 1, wherein a pressing load that presses the pressing member against the contact member is set to be small according to a region in which the pressing force reducing unit is provided. 4. The transfer device according to any one of 4.   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.

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