JP5045568B2 - Belt-type cooling device and image forming apparatus - Google Patents

Description

  The present invention relates to a belt-type cooling device and an image forming apparatus using the belt-type cooling device.

2. Description of the Related Art Image forming apparatuses in which a toner image formed by attaching toner to a latent image due to a difference in electrostatic potential is transferred onto a recording medium and then fixed by heating are widely used. In recent years, the temperature of a toner image after fixing has been controlled for the purpose of improving the image quality of the toner image fixed on a recording medium, and it has been proposed to manage the cooling after heating, in particular. Yes.
Regarding such a technique, for example, there are those described in Patent Document 1 and Patent Document 2.

  Patent Document 1 discloses a fixing device including an endless belt that is stretched around a heating roll and a peeling roll, and a pressure roll that is pressed against the heating roll via the endless belt. . A cooling device is disposed in contact with the inner peripheral surface of the endless belt, and after the recording sheet on which the image is formed passes through the pressure contact area between the endless belt and the pressure roll, the portion where the cooling device is disposed is arranged. Good fixing is achieved by passing the film. A heat-soluble release agent such as wax is supplied to the inner peripheral surface of the endless belt in order to suppress wear and deterioration of the endless belt due to contact with the cooling device.

Patent Document 2 describes an image forming apparatus including a first fixing unit in the recording medium conveyance direction and a second fixing unit downstream thereof. The second fixing unit includes two sets of belt units each having a heating roller, a separation roller, and an endless belt stretched over the heating roller, from a position where the belt contacts the heating roller to a position where the belt contacts the separation roller. The belts are in contact with each other. And the cooling means is provided inside each belt in the range where these two belts are in contact with each other. Then, a recording medium with a toner image attached is fed between these mutually contacting belts, and the toner image is heated and cooled.
JP 2002-99173 A JP 2006-201657 A

  In the present invention, when one or both of two endless belts of the same length that are pressed against each other are extracted and replaced with a new endless belt or two endless belts are replaced with each other, It is an object of the present invention to provide a belt-type cooling device that can be performed without removing a support frame and an image forming apparatus using the belt-type cooling device.

In order to solve the above-mentioned problems, the invention according to claim 1 is characterized in that the first conveyor belt that is endlessly stretched by a plurality of roll-shaped members and rotates in the circumferential direction, and endlessly the first first belt. The recording medium, which is stretched around a plurality of roll-shaped members so that the outer peripheral surfaces of the conveyance belt and the mutual outer surface are in contact with each other and rotated in the circumferential direction, is sandwiched between the first conveyance belt and conveyed. A second support belt; a first support member that supports a plurality of roll members that stretch the first transport belt; and a plurality of roll members that stretch the second transport belt. A second support member; and a cooling unit that is disposed in contact with an inner peripheral surface of the first transport belt and cools the recording medium. The first transport belt and the second transport belt and is a circumferential length is the same, what can be used interchangeably between themselves There, the first at least one of the support member and the second support member, by moving, the outer peripheral surface of the first conveyor belt and second conveyor belts which are in contact spaced When the outer peripheral surfaces of the first transport belt and the second transport belt are separated from each other, the first transport belt and the second transport belt are moved in the width direction of the belt. 1 so that both the first support member and the second support member are opposite to the first end in the width direction of the belt so that they can be extracted in the direction of the end of 1. Both the first support member and the second support member are end portions on the side where the belt is pulled out in the width direction of the first transport belt and the second transport belt. Is supported so that can be flipped up The first support member is supported so as to be rotatable about a rotation axis, the first support member is sprung upward and rotated about the rotation axis, and the first conveyance belt and the second conveyance belt are separated from each other. After that, the belt-type cooling device is provided in which the first support member is further pushed upward, whereby the second support member is pushed upward .

According to a second aspect of the present invention, in the belt-type cooling device according to the first aspect, the angle at which the first support member can be pushed up is an angle at which the second support member can be pushed up. Shall be different .

  The invention according to claim 3 is the belt-type cooling device according to claim 1 or 2, wherein the first support member or the second support member includes at least one of a plurality of roll-shaped members. It shall be supported so as to be movable so as to loosen the tension of the tensioned conveyor belt.

  According to a fourth aspect of the present invention, in the belt-type cooling device according to the first, second, or third aspect, the first and second conveyor belts supported so as to contact each other are covered. The first support member and the second support member are pulled out from the storage body in a state where the first conveyance belt and the second conveyance belt are in contact with each other. It is assumed that the first support member or the second support member is movable in a state where the first support member or the second support member is pulled out from the container.

  According to a fifth aspect of the present invention, there is provided an image forming unit that forms a toner image by attaching toner to a latent image due to a difference in electrostatic potential; A transfer device that transfers the toner image transferred to the recording medium after being transferred to the body, a fixing device that heats and fixes the toner image transferred to the recording medium to the recording medium, and a recording in which the toner image is fixed A cooling device that cools the medium while transporting the medium, wherein the cooling device is the belt-type cooling device according to any one of claims 1 to 5, further comprising: An image forming apparatus comprising: a thickness detection unit that detects a thickness; and a warning output unit that outputs a warning that the thickness of the first conveyance belt has decreased according to a detection result of the thickness detection unit. provide.

In the belt-type cooling device according to the first aspect of the present invention, one or both of the two conveyor belts of the same length that are in pressure contact with each other are extracted and replaced with a new conveyor belt or the two conveyor belts with each other. This can be carried out easily as compared with the case of removing the support member that supports the two conveyor belts. In addition, it is possible to easily extract and replace the conveyor belts, compared to those in which the support members of the respective conveyor belts are not rotatably supported at one end in the width direction of these conveyor belts. Become.

In the belt-type cooling device according to the second aspect of the present invention , the conveyor belt can be easily extracted and replaced.

  In the belt-type cooling device according to the third aspect of the present invention, it is possible to easily extract and attach the conveyor belt as compared with the belt-type cooling device that stretches the conveyor belt and does not move so as to loosen the belt tension. Become.

  In the belt-type cooling device according to the fourth aspect of the present invention, compared to a belt-type cooling device that does not have a configuration that allows the first support member and the second support member that support the transport belt to be pulled out from the container, It can be easily removed and installed.

  In the image forming apparatus of the invention according to claim 5, when the thickness of the conveying belt is changed, this is detected, and one or both of the two conveying belts having the same length are extracted and replaced with a new conveying belt. Alternatively, the exchange between the two conveyor belts can be easily performed as compared with those not including the configuration of the present invention.

Hereinafter, embodiments of the invention according to the present application will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention.
The image forming apparatus 1 includes six image forming units 10a, 10b, 10c, 10d, 10e, and 10f that form toner images of yellow, magenta, cyan, black, light magenta, and light cyan. The endless belt-like intermediate transfer body 11 is supported so as to face each other, and is driven so that the peripheral surface circulates. On the downstream side of the position where the image forming units 10a, 10b, 10c, 10d, 10e, and 10f face each other in the moving direction of the peripheral surface of the intermediate transfer member 11, a transfer roll 12 that is a transfer device in this embodiment is an intermediate transfer member. 11, the recording sheet is fed from the sheet tray 13 through the conveyance path 14 to the secondary transfer portion. A fixing device 15 that heats and presses the toner image, which is a fixing device in this embodiment, and presses the toner image on the recording sheet is provided downstream of the secondary transfer portion in the recording sheet conveyance path. Is provided with a cooling device 16 for cooling the recording sheet and the toner image fixed on the recording sheet as a belt-type cooling device in this embodiment. Further downstream, a plurality of conveyance roll pairs 17 and a paper discharge tray 18 for conveying the recording sheet are provided to accommodate the recording sheet on which the toner image is fixed. Further, on the downstream side of the cooling device 16, a double-sided conveyance path 19 that reverses the recording sheet and feeds it to the secondary transfer unit in order to form an image on the back surface of the recording sheet is provided.

  Each of the image forming units 10 can form any one of yellow, magenta, cyan, black, light magenta, and light cyan toner images. As shown in FIG. They are arranged at predetermined intervals in the direction, and each is detachable.

  Each of the image forming units 10 a, 10 b, 10 c, 10 d, 10 e, and 10 f has a photosensitive drum 2 on which an electrostatic latent image is formed, and around each photosensitive drum 2, the photosensitive drum 2 is formed. A charging device 3 for charging the surface of the photosensitive drum 2 substantially uniformly, a developing device 4 for transferring toner to a latent image formed on the photosensitive drum to form a toner image, and a toner on the photosensitive drum 2 A transfer device 5 that primarily transfers an image onto the intermediate transfer member 11 and a cleaning device 6 that collects toner remaining on the photosensitive drum 2 after the transfer are provided. An exposure device 7 for writing an electrostatic latent image by irradiating each uniformly charged photosensitive drum 2 with image light based on an image signal is provided.

  The photoconductor drum 2 is formed by forming an organic photoconductor layer on the peripheral surface of a cylindrical member made of metal, and the metal portion is electrically grounded.

  The charging device 3 includes a roll-shaped member in which a stainless steel cylindrical core metal is covered with a medium-resistance rubber, and the surface of the photosensitive drum 2 is applied by applying a voltage in which an AC component is superimposed on a DC component. Is charged to a desired voltage. The DC component Vh of the voltage applied to the charging device 3 can be set to −600 [V], for example, and the superimposed AC peak-to-peak value Vbpp can be set to 1400 [V], for example.

  The exposure device 7 generates a flashing laser beam based on an image signal, and scans this in the main scanning direction (axial direction) of each photosensitive drum 2 by a polygon mirror. As a result, the potentials of the portions of the photosensitive drums 2 where the laser light is illuminated are attenuated, and electrostatic latent images corresponding to the images of the respective colors are formed on the surface of the photosensitive drums 2 due to the difference in electrostatic potential.

  The developing device 4 uses a two-component developer containing toner and a magnetic carrier as a developer, and is magnetically attracted to the developing roll and conveyed. Then, a layer having an appropriate thickness is formed on the developing roll by a regulating blade and supplied to a position facing the photosensitive drum 2. A developing bias voltage Vd is applied to the developing roll in order to transfer the toner to the electrostatic latent image on the photosensitive drum 2, and the developing bias voltage Vd can be set to, for example, −500 [V]. . Further, in the image forming apparatus 1 according to the present embodiment, the sub toner storage chamber 8 which is a preliminary storage chamber for the toner replenished to the developing device 4 includes the image forming units 10a, 10b, 10c, 10d, 10e, and 10f. It is provided above.

  The intermediate transfer body 11 is disposed to face the image forming units 10a, 10b, 10c, 10d, 10e, and 10f, and is formed of a synthetic resin such as flexible PET or polyimide film. . Inside the intermediate transfer body 11, a drive roll 21, a counter roll 22 and a support roll 23 are arranged. The intermediate transfer body 11 is stretched around these and moves in the direction of arrow A shown in the figure. It is supposed to be.

  The transfer roll 12 is provided at a position facing the opposing roll 22 and is pressed against the opposing roll 22 via the intermediate transfer body 11. The transfer roll 12 is a roll formed by forming an outer peripheral portion with a conductive rubber material on a metal core, and a bias voltage for transfer is applied between the opposite roll 22. is there.

  The fixing device 15 includes a fixing belt 15b stretched by a plurality of roll-shaped members including a heating roll 15a including a heating source, and a pressure roll 15c pressed against the heating roll 15a via the fixing belt 15b. It has. Then, the recording sheet is sent between the fixing belt 15a and the pressure roll 15c at a portion where the heating roll 15a and the pressure roll 15c are pressed against each other, and the toner image is fixed on the recording sheet by heating and pressing. It is supposed to be.

  The heating roll 15a has an elastic body layer such as heat-resistant rubber formed on the peripheral surface of a metal core, and incorporates a halogen heater as a heating source. The pressure roll 15c is obtained by coating a metal cored bar with a surface release layer.

  The conveying roll pair 17 provided on the downstream side of the fixing device 15 includes a driving roll and a pinch roll facing a surface on which an image of the recording sheet is held, and is opposed to both sides of the recording sheet conveying path. It is provided to come into contact. Each of the rolls is formed by attaching a plurality of synthetic resin cylinders having a small width to a metal shaft with a gap therebetween, and transports a recording sheet that comes into contact with the roll when the drive roll is driven to rotate. Further, the pinch roll is supported so as to be freely rotatable, and smoothly conveys the recording sheet following the rotational driving of the drive roll.

The cooling device 16 will be described below.
2 is a schematic sectional view of the cooling device 16, FIG. 3 is a schematic front view, and FIG. 4 is a schematic side view.
As shown in these drawings, the cooling device 16 includes an upper belt unit 40 and a lower belt unit 50. The upper belt unit 40 and the lower belt unit 50 are used as a first conveying belt in the present embodiment. There are an upper conveying belt 41 used and a lower conveying belt 51 used as the second conveying belt in the present embodiment, which are endless and have the same circumference, and are stretched by a plurality of roll-shaped members. The upper conveyor belt 41 and the lower conveyor belt 51 are arranged so that their outer peripheral surfaces are pressed against each other with a predetermined force, and the recording sheet fed from the fixing device 15 is sandwiched between the contact areas and heated. The recording sheet and the toner image on the recording sheet are cooled.

  The upper belt unit 40 is disposed above the lower belt unit 50 and is movably supported so as to be separated from the lower belt unit 50. When the upper belt unit 40 is separated from the lower belt unit 50, the respective belts can be removed and replaced.

The upper belt unit 40 includes an upper belt drive roll 42 and a plurality of upper belt tension rolls 43a, 43b, 43c that are parallel to each other, and the upper conveyor belt 41 is wound around these rolls 42, 43. It is stretched. Also, a thickness detection sensor 44 that detects the thickness of the upper conveyance belt 41 and a cooling member 45 that is provided inside the endless upper conveyance belt 41 and is used as a cooling means in the present embodiment for cooling the upper conveyance belt 41. These are supported by an upper belt frame 46 that functions as a first support member in this embodiment .

  As shown in FIG. 4, the upper belt frame 46 supports the front side of the upper belt drive roll 42 and the upper belt tension roll 43, that is, the end closer to the position where the person who operates the image forming apparatus stands. It includes a front support plate 46a, a rear support plate 46b that supports the other end, that is, a rear end, and a connection support member 46c that connects and integrates them. The upper belt frame 46 is rotatably supported with respect to the support base 61 of the cooling device via a rotation shaft 47 and a bearing portion 64 provided in the horizontal direction further on the rear side of the rear support plate 46b. Yes. Further, the front support plate 46a is provided with a handle 48 as a grip portion used when the upper belt unit 40 is moved and separated from the lower belt unit 50.

  On the other hand, the lower belt unit 50 includes an endless lower conveying belt 51, a lower belt driving roll 52 and a lower belt stretching roll 53 that stretch the lower conveying belt 51. It is supported by a lower belt frame 56 that functions as a second support member in this embodiment. The lower belt frame 56 includes a front support plate 56a, a rear support plate 56b, and a connection support member 56c that connects these integrally, and the lower belt drive roll 52 and the lower belt stretch roll. 53 is rotatably supported between the front support plate 56a and the rear support plate 56b.

Similarly to the upper belt frame 46, the lower belt frame 56 also rotates with respect to the support base 61 of the cooling device via a rotation shaft 57 and a bearing portion 64 provided in the horizontal direction further rearward of the rear support plate 56b. Supported as possible. The position is fixed by a support base 61 a provided on the support base 61.
The front support plate 46a of the upper belt frame 56 is provided with a connecting member 68 for connecting to the support base 61a. By locking the connecting member 68 to the support base 61a, the upper conveyance belt 41 and the lower conveyance belt 51 are brought into contact with each other, and the relative positions of both are restricted. Further, the connecting member 68 facilitates the connection so that the upper belt frame 46 and the lower belt frame 56 can be relatively moved when the upper conveyor belt 41 and the lower conveyor belt 51 are separated from each other. It can be canceled.

  The rotation shaft 47 of the upper belt unit is provided in a direction perpendicular to the axes of the upper belt driving roll 42 and the upper belt stretching roll 43, and is coupled to the lower portion of the rear support plate 46b. The rotating shaft 47 is supported by the support base 61 via the bearing portion 64, and can rotate with respect to the support base 61. Similarly, the rotation shaft 57 of the lower belt unit 50 is provided in a direction perpendicular to the axes of the lower belt driving roll 52 and the lower belt stretching roll 53, and is coupled to the rear support plate 56b to be a support base 61. Are supported via bearings 64.

  The support base 61 is supported on a fixed rail 63 supported by the frame 1 b of the image forming apparatus main body via a slide rail 62. The slide rail 62 slides on the fixed rail 63 and can move forward. The support base 61 is movable on the slide rail 62 and moves forward to a position where it moves forward and projects from the slide rail 62. Accordingly, as shown in FIG. 6, the operator holds the handle 48, pulls out the cooling device 16 to the front side, and pushes the front support plate 46a upward, so that the upper belt frame 46 is provided on the rear side. The upper conveyor belt 41 is rotated together with the rotating shaft 47 so as to move away from the lower conveyor belt 51 and jump upward.

  The upper belt unit 40 is provided with a thickness detection sensor 44 used as a thickness detection means in the present embodiment, and detects the thickness of the upper conveyance belt 41. Thus, when a change in thickness occurs due to wear or deterioration due to the inner peripheral surface of the upper conveyance belt 41 being rubbed against the cooling member 45, this is detected, and the detection signal is sent to the warning signal output unit 25. It is supposed to be entered. The warning signal input unit 25 functions as a warning output unit 27 in the present embodiment together with the operation panel 26, and the operation panel 26 displays a warning by a warning signal output from the warning signal output unit 25. . The warning output unit is not limited to the above-described configuration, and various other modes such as a warning lamp that is turned on by a detection signal from the thickness detection sensor 44 can be adopted.

The cooling member 45 is disposed in contact with the inner peripheral surface of the upper transport belt 41 in a region where the outer peripheral surface of the upper transport belt 41 and the outer peripheral surface of the lower transport belt 51 are in contact with each other. It functions as a heat sink that radiates the conducted heat and cools the upper conveyor belt 41. Accordingly, when a recording sheet having a heated toner image adhered between the upper conveyance belt 41 and the lower conveyance belt 51 is fed, the upper conveyance belt 41 contacts the toner image and cools the toner image. Yes. The cooling member 45 is made of, for example, aluminum, and includes a heat absorbing portion 45a that is pressed against the inner peripheral surface of the upper conveyance belt 41, and a plurality of heat radiating portions 45b provided so as to protrude from the heat absorbing portion.
It is also possible to provide an air cooling mechanism that supplies an air flow to the heat radiating portion 45b of the cooling member 45 to perform air cooling.

  A part of the upper belt tension roll provided in the upper belt unit 40, in this embodiment, the two upper belt tension rolls 43a and 43b and the lower belt tension roll 53 provided in the lower belt unit 50 are The upper conveyor belt 41 or the lower conveyor belt 51 is supported so as to be retractable, and is urged toward the upper conveyor belt 41 or the lower conveyor belt 51 by elastic members such as springs 72 and 74 as shown in FIG. ing. Then, with these tension rolls 43a, 43b, 53 retracted from the belts 41, 51, the positions can be restrained by the restraining brackets 71, 73 shown in FIG. 3, and the tension of each belt can be loosened. It has become.

As shown in FIG. 4, the lower belt drive roll 52 receives a driving force from a drive motor 66 supported by a frame 1b of the main body of the image forming apparatus via a drive transmission gear 67 and a drive gear 81, and lower conveyance. A driving force is applied to the belt 51. Further, as shown in FIG. 5 when the cooling device 16 is viewed from the back side, the rotational driving force is applied from the driving gear 81 that transmits the driving force to the lower belt driving roll 52 to the upper belt driving roll 42 included in the upper belt unit 40. Are provided with a plurality of drive transmission gears 82a, 82b, 82c. As a result, the upper conveyor belt 41 and the lower conveyor belt 51 are driven so as to move around at the same speed in the same direction at the portions in contact with each other.
In addition, the driving force is transmitted to the upper conveyance belt 41 by friction of the surface at a portion in pressure contact with the lower conveyance belt 51, and the upper conveyance belt 41 and the lower conveyance belt 51 are driven in the same direction at the same speed. It may be a thing.

  The upper conveyor belt 41 and the lower conveyor belt 51 are belts that are endless by joining ends of a polyimide film or the like by heat melting or the like. The upper conveyor belt 41 and the lower conveyor belt 51 are formed to have the same circumference, and the circumferential movements of both conveyor belts are driven in the same direction at the same speed.

Next, based on FIGS. 4 and 6 to 11, the operation and belt for moving the upper belt unit 40 above the lower belt unit 50 and releasing the contact between the upper conveyor belt 41 and the lower conveyor belt 51. The procedure for exchanging is described.
When the image forming apparatus is operated, that is, when a recording sheet on which the toner image is fixed is sent to the cooling device 16, the outer peripheral surface of the upper transport belt 41 and the outer peripheral surface of the lower transport belt 51 are in contact with each other as shown in FIG. Then, the recording sheet is sandwiched between them and conveyed. Then, at the time of inspection or when a paper jam occurs in the cooling device 16, the upper conveyor belt 41 and the lower conveyor belt 51 are separated from each other for inspection, or between the upper conveyor belt 41 and the lower conveyor belt 51. Remove the paper jam that occurred in step 1. On the other hand, when the thickness detection sensor 44 provided for the upper conveyor belt 41 detects that the thickness of the upper conveyor belt 41 has decreased to a predetermined value due to wear or the like, a detection signal is input to the warning signal output unit 25. Then, a warning signal is displayed on the operation panel 26 by a warning signal output from the warning signal output unit 25, informing the necessity of replacing the conveyor belt.

  When the inspection of the cooling device 16 as described above, the handling of a paper jam caused by the cooling device 16 or the replacement of the conveying belt is performed, the front door (not shown) of the main body case 1a of the image forming apparatus as shown in FIG. And the operator grasps the handle 48 and pulls the cooling device 16 forward, that is, to the side where the operator operates. As a result, the slide rail 62 slides on the fixed rail 63 and moves forward, and the support base 61 of the cooling device 16 also moves on the slide rail 62, so that almost the entire cooling device 16 is image forming apparatus. It is pulled forward from the case 1a of the main body. At this time, in the case 1a of the image forming apparatus main body, as shown in FIG. 7, a drive transmission gear 67 for transmitting a driving force from the drive motor 66 supported by the frame 1b of the image forming apparatus main body to the lower belt drive roll 52. Is released, and the lower belt unit 50 and the upper belt unit 40 are pulled out of the case 1a while a part of the drive transmission gear 67 is supported on the image forming apparatus main body side.

With the cooling device 16 pulled out of the case 1a as described above, the operator releases the locking metal fitting 68 provided on the front side and pushes the handle 48 upward to lift the upper belt frame 46. Rotate around the rotation axis 47. As a result, the upper belt frame 46 is raised as shown in FIG. 8, and the contact portion between the upper conveyor belt 41 and the lower conveyor belt 51 is released. Further, when the upper belt unit 40 is pushed up, a force for pushing up the upper belt frame 46 and the lower belt frame 56 is transmitted to the lower belt frame 56 via the connecting metal fitting 65 that connects the upper belt frame 46 and the lower belt frame 56 on the rear side. As shown in FIG. 9, the lower belt frame 56 also rotates around the rotation shaft 57 provided on the rear side, and the front side is lifted upward. When the upper belt unit 40 and the lower belt unit 50 are thus moved, both the upper belt frame 46 and the lower belt frame 56 are supported on the rear side, and the front side is supported in a cantilevered manner. It becomes.
In this state, inspection and paper jam processing can be performed.

  In this state where the front is overhanging in a cantilevered manner, if the tension of the conveyor belt is loosened, there will be no obstacle when the conveyor belt is pulled out forward, and it can be easily pulled out to the front side. Can be replaced with a belt. Moreover, since the upper conveyance belt 41 and the lower conveyance belt 51 have the same circumference, they can be exchanged with each other. That is, the lower conveyance belt 51 suspended around the plurality of rollers supported by the lower belt frame 56 is wound around the plurality of rolls of the upper belt unit 46, and the upper conveyance belt 41 used in the upper belt unit 40. Can be easily wound around a plurality of rolls of the lower belt unit 56.

Such replacement of the upper conveyor belt 41 and the lower conveyor belt 51 can be performed by the following procedure.
As shown in FIG. 10, in a state where the upper belt unit 40 and the lower belt unit 50 are separated from each other, a part or all of the tension rolls that stretch both of the conveyor belts are moved in the direction of retreating from the conveyor belt. Loosen the belt tension. In this embodiment, the two upper belt tension rolls 43a and 43b and the lower belt tension roll 53 are moved backward. Then, as shown in FIG. 11, the lower conveyor belt 51 is pulled out to the front side, that is, the operator side, and the lower conveyor belt 51 is hung around the outer side of the upper conveyor belt 41 whose tension has been loosened. Thereafter, the upper conveyor belt 41 is pulled forward on the inner side of the lower conveyor belt 51 and is wound around the lower belt drive roll 52 and the lower belt tension roll 53. The transport belt thus replaced is tensioned by returning the tension rolls 43a, 43b, 53 provided in the upper belt unit 40 and the lower belt unit 50 to their original positions, that is, positions where the belt is stretched. Let it be in a suspended state.
Thereafter, the operator grasps the handle 48, pushes down the upper belt unit 40 downward, and engages the locking metal fitting 68 to fix the lower belt unit 50 to the support base 61. Then, the support base 61 is pushed into a predetermined position in the case 1a of the image forming apparatus, and the drive transmission gear 67 is engaged, so that the recording sheet on which the toner image is fixed can be cooled.

  As described above, when the upper conveyor belt 41 and the lower conveyor belt 51 are exchanged with each other, for example, the thickness detection sensor 44 detects that the thickness of the upper conveyor belt 41 is decreased, and a warning is issued. Can be done when. Even if the upper conveyor belt 41 is worn due to friction with the cooling member 45 or the like, the lower conveyor belt 51 is less likely to be worn. By exchanging the upper conveyor belt 41 and the lower conveyor belt 51, the toner image is directly changed. The thickness of the upper conveying belt 41 that is in contact is maintained at a value close to a predetermined value. As a result, the heated toner image can be appropriately fixed, and the occurrence of image defects such as uneven gloss on the toner image is suppressed. Then, exchanging the upper conveyor belt 41 and the lower conveyor belt 51 as described above is effective as a countermeasure when it takes time to procure a new conveyor belt and immediately resumes good image formation. can do. The replacement does not have to be performed by an engineer or the like specially trained in the maintenance of the image forming apparatus, and can be easily performed by the user of the image forming apparatus.

In the above-described embodiment, the two belt units are arranged vertically as the upper belt unit 40 and the lower belt unit 50, but these are not limited to those arranged vertically, and are substantially the same in the left and right or front and rear. It may be arranged at a height.
Further, the upper belt unit 40 that stretches the upper transport belt 41 and the lower belt unit 50 that stretches the lower transport belt 51 relatively move while being pulled out from the case 1a of the image forming apparatus main body. However, the upper belt unit 40 and the lower belt unit 50 may be moved within the case 1a without being pulled out of the case. The form in which the upper belt unit 40 and the lower belt unit 50 move so that the upper conveyor belt 41 and the lower conveyor belt 51 are separated from each other is also the axis of the horizontal rotation axis as in the above embodiment. It is not limited to one that rotates and moves around, but may be one that moves while being supported by a rod-like member that moves in the axial direction, one that uses a link mechanism, or the like. In other words, when the two conveyor belts are separated from each other, the roll-shaped member that stretches these belts or the frame that supports them is supported on one side in the width direction of the conveyor belt, and supports the conveyor belt. Various support forms can be adopted as long as the structure can be pulled out in a direction that is not performed.

1 is a schematic configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention. It is a schematic sectional drawing of the belt-type cooling device with which the image forming apparatus shown in FIG. 1 was equipped. It is a schematic front view of the belt-type cooling device shown in FIG. It is a schematic side view of the belt-type cooling device shown in FIG. FIG. 3 is a schematic rear view of the belt-type cooling device shown in FIG. 2. FIG. 3 is a schematic side view illustrating a state in which the belt-type cooling device illustrated in FIG. 2 is pulled out from a case of the image forming apparatus main body. FIG. 3 is a schematic view showing the inside of the image forming apparatus main body when the belt-type cooling device shown in FIG. 2 is pulled out from the case of the image forming apparatus main body. It is a schematic side view which shows the state which the upper side belt unit of the belt-type cooling device shown in FIG. 2 raised. FIG. 3 is a schematic front view showing a state in which a lower belt unit is also raised in conjunction with an upper belt unit of the belt-type cooling device shown in FIG. 2. FIG. 3 is a schematic diagram illustrating a procedure for exchanging an upper conveyance belt and a lower conveyance belt with each other in the belt-type cooling device illustrated in FIG. 2. FIG. 3 is a schematic diagram illustrating a procedure for exchanging an upper conveyance belt and a lower conveyance belt with each other in the belt-type cooling device illustrated in FIG. 2.

Explanation of symbols

1: image forming device, 2: photosensitive drum, 3: charging device, 4: developing device, 5: transfer device, 6: cleaning device, 7: exposure device, 8: sub-toner storage chamber,
10a, 10b, 10c, 10d, 10e, 10f: image forming unit, 11: intermediate transfer member, 12: transfer roll, 13: sheet tray, 14: conveyance path, 15: fixing device, 15a: heating roll, 15b: fixing Belt: 15c: pressure roll, 16: cooling device, 17: transport roll pair, 18: paper discharge tray, 19: duplex transport path, 21: drive roll, 22: opposing roll, 23: support roll,
25: Warning signal output unit, 26: Operation panel, 27: Warning output unit,
40: Upper belt unit, 41: Upper conveyor belt, 42: Upper belt drive roll, 43: Upper belt tension roll, 44: Thickness detection sensor, 45: Cooling member, 46: Upper belt frame, 47: Rotating shaft, 48 : Handle,
50: Lower belt unit 51: Lower conveyor belt 52: Lower belt drive roll 53: Lower belt tension roll 56: Lower belt frame 57: Rotating shaft
61: Support base part, 62: Slide rail, 63: Fixed rail, 64: Bearing part, 65: Connecting bracket, 66: Drive motor, 67 Drive transmission gear, 68: Locking bracket,
71, 73: Restraint fitting, 72, 74: Spring, 81: Drive gear of lower belt drive roll, 82: Drive transmission gear

Claims (5)

A first conveyor belt which is endless and stretched by a plurality of roll-shaped members and rotates in the circumferential direction;
An endless recording medium that is stretched around a plurality of roll-shaped members so that the outer peripheral surfaces of the first conveying belt are in contact with each other and is rotated in the circumferential direction is formed on the first conveying belt. A second conveyor belt sandwiched between and conveyed,
A first support member that supports a plurality of roll members that stretch the first conveyor belt;
A second support member that supports a plurality of roll members that stretch the second transport belt;
A cooling means that is disposed in contact with the inner peripheral surface of the first conveying belt and cools the recording medium,
The first conveyor belt and the second conveyor belt have the same circumference and can be used interchangeably with each other,
At least one of the first support member and the second support member moves so that the outer peripheral surfaces of the first and second conveyor belts in contact with each other are separated from each other. Is supported by
When the outer peripheral surfaces of the first transport belt and the second transport belt are separated from each other, the first transport belt and the second transport belt are extracted in the first end direction in the width direction of the belt. To be possible, both the first support member and the second support member are supported on the end portion side opposite to the first end portion in the width direction of the belt,
Both the first support member and the second support member are configured so that the end portions on the side where the belt is pulled out in the width direction of the first transport belt and the second transport belt are flipped upward. The end of the supported side is supported so as to be rotatable about the rotation axis;
The first support member is flipped upward and rotated around the rotation axis to separate the first transport belt and the second transport belt, and then further pushes the first support member upward. Thus , the belt-type cooling device is characterized in that the second support member is pushed upward in conjunction with the second support member . The belt-type cooling device according to claim 1 , wherein an angle at which the first support member can be pushed up is different from an angle at which the second support member can be pushed up .   The first support member or the second support member supports at least one of a plurality of roll-shaped members so as to be movable so as to loosen the tension of the stretched conveyor belt. The belt-type cooling device according to claim 1 or 2. A housing for housing the first transport belt and the second transport belt supported so as to be in contact with each other;
The first support member and the second support member are supported so that they can be pulled out from the container while the first transport belt and the second transport belt are in contact with each other,
4. The belt type according to claim 1, wherein the first support member or the second support member is movable while being pulled out from the container. Cooling system. An image forming unit that forms a toner image by attaching toner to a latent image due to a difference in electrostatic potential;
A transfer device that directly transfers the toner image to a transported recording medium or transfers the toner image to an intermediate transfer member, and then transfers the toner image to a transported recording medium;
A fixing device that heats and fixes the toner image transferred to the recording medium to the recording medium;
A cooling device that cools the recording medium on which the toner image is fixed while being conveyed,
The cooling device is a belt-type cooling device according to any one of claims 1 to 5,
Furthermore, a thickness detection means for detecting the thickness of the first conveyor belt,
An image forming apparatus comprising: a warning output unit that outputs a warning that the thickness of the first conveying belt has decreased in accordance with a detection result of the thickness detection unit.

Images