JP7443143B2 - Recording material cooling device - Google Patents

Description

The present invention relates to a recording material cooling device that cools a recording material via a belt and is suitable for use in an image forming apparatus such as a printer, a copying machine, a facsimile machine, or a multifunctional device.

In an image forming apparatus, a toner image formed on a recording material is heated and pressurized by a fixing device to fix the toner image on the recording material. Therefore, the temperature of the recording material conveyed from the fixing device becomes higher than that before fixing. If the recording materials after the toner image is fixed are discharged to the stacking section and stacked while the temperature is still high, there is a possibility that the stacked recording materials will stick to each other due to the toner. In order to suppress such sticking of the recording material, a recording material cooling device is provided that lowers the temperature of the recording material after the toner image is fixed (Patent Document 1). The recording material cooling device described in Patent Document 1 is a belt cooling type device, in which at least one of a pair of belts that sandwich and convey the recording material that has passed through the fixing device is cooled by a heat sink, and the recording material is cooled through the cooled belt. I'm trying to lower the temperature.

In such a belt cooling type device, in order to efficiently cool the belt, a film-like belt is brought into contact with a heat sink under a predetermined pressure. In that case, the rotating belt is likely to be scraped by the heat sink. Therefore, abrasion powder (also called shaving powder) of the belt is generated, and the abrasion powder may adhere to the inner circumferential surface of the belt together with paper powder, dust, and the like. If such deposits get between the heat sink and the belt, thermal resistance increases and the cooling performance of the recording material can be reduced. Therefore, an apparatus has been proposed that includes a scraper that removes the deposits that have adhered to the inner peripheral surface of the belt from the belt, and a storage box that accommodates the deposits that have been removed by the scraper (Patent Document 2).

Further, in the case of the above-described belt cooling type recording material cooling device, steering control is performed to suppress deviation of the belt in the width direction and meandering of the belt. Steering control is performed by tilting the steering roller that tensions the belt moment by moment based on the detection results of an end sensor that has a tracking member that contacts the end of the belt and follows its movement. This is done to perform positioning dynamically.

Japanese Patent Application Publication No. 2009-181055 JP2015-94847A

By the way, as described above, if the belt is scraped by the heat sink or if the belt deteriorates over time, the cooling performance of the belt decreases, so the belt is provided to be replaceable. However, conventionally, it has been difficult for an operator to wear the belt while stabilizing its posture. In particular, in the case of a device equipped with the above-mentioned scraper and end sensor, when the operator attaches the belt, the worker must contact the scraper with the inner peripheral surface of the belt and also bring the belt end into contact with the following member of the end sensor. Therefore, it was time consuming and troublesome to put on the belt.

In view of the above-mentioned problems, the present invention provides a recording material cooling device using a belt cooling method, which is equipped with a scraper that removes deposits from the inner circumferential surface of a belt, and an end sensor that contacts the end of the belt and detects the position of the end of the belt. The purpose of the present invention is to provide a device that allows an operator to easily replace a belt.

A recording material cooling device according to the present invention includes a rotatable endless belt, a first roller that stretches the belt, a second roller that stretches the belt together with the first roller, and an inner part of the belt. In a recording material cooling device that cools a recording material on which a toner image is fixed by heating, the cooling means includes a cooling means that cools the belt by contacting a circumferential surface of the belt, and the cooling means cools the recording material on which a toner image is fixed by heating. a cleaning means having a removing member that comes into contact with the inner circumferential surface of the belt and removes deposits attached to the inner circumferential surface; and a container that accommodates the deposits removed by the removing member; and an end of the belt. a position detecting means having a following member that contacts the width direction of the belt and follows the movement of the belt in the width direction, and detecting the position of the end of the belt according to the position of the following member; moving means for moving the second roller between the first position and a second position where the belt is detachably loosened in the width direction; The present invention is characterized by comprising a guide member that supports the worn belt from below in the direction of gravity and guides it toward the follow-up member so that the leading end in the mounting direction contacts the follow-up member.

According to the present invention, the cleaning means includes a removing member that removes deposits from the inner circumferential surface of the belt, and the position detecting means detects the end position of the belt according to the position of the follower member that follows the movement of the belt. In the recording material cooling device, an operator can easily replace the belt.

FIG. 1 is a schematic diagram showing the configuration of an image forming apparatus. FIG. 1 is a schematic diagram showing a recording material cooling device of this embodiment. FIG. 3 is a perspective view of the recording material cooling device seen from the back side of the device. FIG. 3 is a perspective view for explaining a steering mechanism. FIG. 3 is a diagram for explaining a belt contact/separation mechanism, in which (a) is a contact state and (b) is a separated state. FIG. 3 is a diagram illustrating a belt tensioning mechanism section. FIG. 3 is a perspective view for explaining an end sensor. FIG. 3 is a top view for explaining the belt attachment guide. FIG. 3 is a perspective view for explaining a belt attachment guide. FIGS. 3A and 3B are schematic diagrams for explaining belt attachment guides, in which (a) the belt is not stretched, (b) the belt is stretched, and (c) a comparative example without the belt attachment guide. FIG. 2 is a schematic diagram showing an example in which a recording material cooling device is provided outside an image forming apparatus.

<Image forming device>
The recording material cooling device of this embodiment will be described below. First, a schematic configuration of a suitable image forming apparatus using the recording material cooling device of this embodiment will be described with reference to FIG. The image forming apparatus 100 shown in FIG. 1 is an electrophotographic tandem full-color printer. The image forming apparatus 100 has image forming sections Pa, Pb, Pc, and Pd that form yellow, magenta, cyan, and black images, respectively. The image forming apparatus 100 generates toner according to image information from a document reading device (not shown) connected to the apparatus main body 100A or an external device (not shown) such as a personal computer communicably connected to the apparatus main body 100A. An image is formed on the recording material S. Examples of the recording material S include various types of sheet materials such as plain paper, cardboard, rough paper, textured paper, coated paper, plastic film, cloth, and the like.

The recording material conveyance process of the image forming apparatus 100 will be described. The recording materials S are stored in a stacked manner in a paper feed cassette 10, and are sent out from the paper feed cassette 10 by a paper feed roller 13 in accordance with the image forming timing. The recording material S sent out by the paper feed roller 13 is conveyed to the registration roller 12 disposed in the middle of the conveyance path 114. After the recording material S is corrected for skew and timing by the registration roller 12, the recording material S is sent to the secondary transfer section T2. The secondary transfer portion T2 is a transfer nip portion formed by the inner secondary transfer roller 14 and the outer secondary transfer roller 11, and in response to a secondary transfer voltage being applied to the outer secondary transfer roller 11, A toner image is transferred onto the recording material.

In contrast to the process of conveying the recording material S to the secondary transfer section T2 described above, a process of forming an image that is conveyed to the secondary transfer section T2 at the same timing will be described. First, the image forming sections will be explained. The image forming sections Pa, Pb, Pc, and Pd for each color are different from each other except that the toner colors used in the developing devices 1a, 1b, 1c, and 1d are yellow, magenta, cyan, and black. are constructed in almost the same way. Therefore, below, the black image forming section Pd will be explained as a representative, and the explanation of the other image forming sections Pa, Pb, and Pc will be omitted.

The image forming section Pd mainly includes a developing device 1d, a charging device 2d, a photosensitive drum 3d, a photosensitive drum cleaner 4d, an exposure device 5d, and the like. The surface of the photosensitive drum 3d rotated in the direction of arrow R1 is uniformly charged in advance by a charging device 2d, and then an electrostatic latent image is formed by an exposure device 5d driven based on an image information signal. Ru. Next, the electrostatic latent image formed on the photosensitive drum 3d is developed into a toner image using a developer by the developing device 1d. Then, in response to a primary transfer voltage being applied to the primary transfer roller 6d disposed with the image forming portion Pd and the intermediate transfer belt 80 in between, the toner image formed on the photosensitive drum 3d is transferred to the intermediate transfer belt 80. Primary transfer is performed on top. A small amount of primary transfer residual toner remaining on the photosensitive drum 3d is collected by a photosensitive drum cleaner 4d.

The intermediate transfer belt 80 is stretched by the secondary transfer inner roller 14, the tension roller 15, and the tension roller 16, and is driven in the direction of arrow R2. In the case of this embodiment, the tension roller 16 also serves as a drive roller that drives the intermediate transfer belt 80. The image forming process of each color, which is processed in parallel by the image forming units Pa to Pd, is performed at the timing of sequentially superimposing the toner image of the upstream color that has been primarily transferred onto the intermediate transfer belt 80. As a result, a full-color toner image is finally formed on the intermediate transfer belt 80 and conveyed to the secondary transfer section T2. Note that the secondary transfer residual toner after passing through the secondary transfer portion T2 is removed from the intermediate transfer belt 80 by the transfer cleaner 22.

Through the transport process and image forming process described above, the timings of the recording material S and the full-color toner image match in the secondary transfer portion T2, and the secondary transfer is performed. After that, the recording material S is conveyed to the fixing device 50, and a predetermined amount of pressure and heat is applied to fix the toner image on the recording material. The fixing device 50 clamps and conveys the recording material S on which the toner image is formed, heats and presses the conveyed recording material S, and fixes the toner image on the recording material S. That is, the toner of the toner image formed on the recording material S by heating and pressurization is melted and mixed, and fixed on the recording material S as a full-color image. In this way, the series of image forming processes ends. In the case of this embodiment, the recording material S on which the toner image has been fixed is conveyed from the fixing device 50 to the recording material cooling device 20 and cooled. For example, the temperature of the recording material S is about 90° C. immediately before the recording material cooling device 20, but after passing through the recording material cooling device 20, the temperature is reduced to about 60° C.

In the case of single-sided image formation, the recording material S cooled by the recording material cooling device 20 is nipped and conveyed by a pair of ejection rollers 105 and is ejected onto the ejection tray 120 as it is. On the other hand, in the case of double-sided image formation, the conveyance path is switched from the path leading to the discharge tray 120 to the double-sided conveyance path 111 by a switching member 110 (called a flapper, etc.), and the recording material S sandwiched and conveyed by the discharge rollers 105 is transferred to the double-sided conveyance path. It is sent to the transport path 111. Thereafter, the leading and trailing ends are exchanged by the reversing roller 112 and sent to the conveying path 114 again via the double-sided path 113. The subsequent conveyance and image forming process on the back side (second side) are the same as described above, so description thereof will be omitted.

<Recording material cooling device>
Next, the recording material cooling device 20 of this embodiment will be explained using FIGS. 2 to 5. The recording material cooling device 20 of this embodiment is a belt cooling type cooling device. As shown in FIG. 2, the recording material cooling device 20 includes an endless first belt 21 and an endless second belt 25 that sandwiches and conveys the recording material S with the first belt 21. Both the first belt 21 and the second belt 25 are film-like endless belts made of, for example, high-strength polyimide resin and have a thickness of 100 μm and a belt circumference of 942 mm.

As shown in FIG. 2, the first belt 21 is stretched over a plurality of first belt tension rollers (22a to 22d), and at least one of the first belt tension rollers (22a to 22d) is It is rotated by a drive motor (not shown). In the case of this embodiment, the first belt 21 is moved in the direction of arrow Q by, for example, rotating the roller 22d by a drive motor (not shown). The roller 22d serving as a driving roller has, for example, a rubber layer with a thickness of 1 mm on the surface layer, and is formed to have an outer diameter of 40 mm.

The roller 22b as a second roller is provided so as to be able to stretch the first belt 21 together with the roller 22c by coming into contact with the inner circumferential surface of the first belt 21. This is a steering roller that controls the shift in direction. The roller 22b has a rubber layer with a thickness of 1 mm on its surface, and can control the meandering of the first belt 21 by performing steering control to change the steering angle with respect to the roller 22c as the first roller. The roller 22b is rotatably supported by a roller holder 81a, and is steering-controlled by a steering mechanism 400, which will be described later. Therefore, an end sensor 90 that detects the end position of the first belt 21 is provided at one location on the rotation path of the first belt 21 . Based on the detection signal of the end sensor 90, the end position of the rotating first belt 21 is detected. The steering angle of the roller 22b (steering roller) is adjusted by operating the steering mechanism 400 based on the end position. Details of the end sensor 90 will be described later.

The steering mechanism 400 and roller holder 81a will be explained using FIGS. 3 and 4. FIG. 3 is a perspective view of the recording material cooling device 20 viewed from the back side of the device. However, in FIG. 3, illustration of the first belt 21 is omitted. As shown in FIG. 3, the steering mechanism 400 is attached to the support frame 200 on the back side of the recording material cooling device 20. The support frame 200 supports one end side of each of the first belt tension rollers (22a to 22d), the heat sink 30, and the belt cleaner 70 (specifically, the storage box 72) shown in FIG. The roller 22b and the steering mechanism 400 are arranged on opposite sides of the support frame 200. The support frame 200 is formed with a through hole through which at least the steering operation shaft 406 is inserted. In this way, the drive conversion unit 410 including the fork plate 404 can control the steering of the roller 22b even when it is located on the opposite side of the roller 22b with respect to the support frame 200.

As shown in FIG. 4, the steering mechanism 400 includes a steering motor 401, a worm 402, a drive conversion section 410, a rotation shaft section 405, a steering operation shaft 406, a position flag 408, and a position sensor 407. The steering motor 401 is a stepping motor, and can rotate in any direction, forward or backward, at a predetermined rotation speed. When the steering motor 401 rotates, a worm 402 attached to the rotating shaft of the steering motor 401 is rotated.

Here, the drive conversion unit 410 integrally includes a worm wheel 403 and a fork plate 404. The rotation of the worm 402 is transmitted to a worm wheel 403 that meshes with the worm 402. At this time, as the worm 402 rotates as the steering motor 401 rotates forward and backward, the worm wheel 403 can reciprocate in the direction of the rotational axis of the steering motor 401. In this way, the drive conversion section 410 can rotate about the rotation shaft section 405 via the worm 402 and the worm wheel 403 as the steering motor 401 rotates. In other words, the drive converter 410 can swing about the rotation shaft 405 as the fork plate 404 swings by receiving the drive of the steering motor 401 via the worm wheel 403. .

The steering mechanism 400 also includes a position flag 87 that moves as the drive converter 84 moves, and a position sensor 88 that detects the position of the drive converter 84 via the position flag 87. Steering control according to the detection result of the position sensor 88 can be executed.

As shown in FIG. 4, the roller holder 81a is provided with a bearing portion 810 for rotatably supporting the rotating shaft of the roller 22d. Furthermore, a steering operation shaft 406 that is fitted into the drive conversion section 410 described above is fixed to the roller holder 81a. The steering operation shaft 406 is fitted into the fork plate 404 of the drive conversion unit 410 with a gap, and can operate together with the drive conversion unit 410 as the fork plate 404 swings. As described above, the steering operation shaft 406 operates in accordance with the swinging of the fork plate 404, so that the roller holder 81a can swing around the swinging center axis (not shown) that intersects the rotational axis of the roller 22b. It becomes. The roller 22b supported by the roller holder 81a also swings following the swing of the roller holder 81a, thereby making it possible to adjust the steering angle of the roller 22b. In this way, when the steering angle of the roller 22b is adjusted, the first belt 21 is reciprocated in the width direction, thereby realizing steering control of the first belt 21 to position it within a predetermined range in the width direction of the first belt 21. can.

Returning to FIG. 2, the roller support mechanism 81 includes the above-described roller holder 81a and a spring 81b that urges the roller holder 81a toward the first belt 21. This spring 81b has a fixed spring pressure that can bias the roller 22b with a biasing force such that the tension of the first belt 21 is approximately 39.2 N (approximately 4 kgf), for example.

On the inner peripheral side of the first belt 21, in addition to a plurality of first belt tension rollers (22a to 22d) and a roller support mechanism 81, a heat sink 30, a belt cleaner 70, and a belt tension mechanism section 61 are provided. There is. The heat sink 30, belt cleaner 70, and belt tension mechanism section 61 will be described later.

On the other hand, the second belt 25 as a rotating body is stretched over a plurality of second belt tension rollers (26a to 26d) and is brought into contact with the outer peripheral surface of the first belt 21. When the second belt 25 and the first belt 21 come into contact with each other, a cooling nip T4 is formed for cooling the recording material S on which the toner image is formed while conveying it. Although not shown, the roller 26d is connected via a drive gear to a drive motor that drives the roller 22d, and when rotated by this drive motor, the second belt 25 rotates in the direction of arrow R. That is, the second belt 25 rotates together with the first belt 21. The roller 26b is a steering roller that controls the deviation of the second belt 25 in the width direction (rotation axis direction of the roller 26c), and performs a steering operation to change the steering angle with respect to the roller 26c with the center portion in the width direction as the pivot center. and control the meandering of the second belt 25. That is, the roller 26b is steered by a steering mechanism 420 similar to the steering mechanism 400 described above.

A plurality of pressure rollers are provided on the inner circumferential side of the second belt 25 in order to press the second belt 25 toward a heat sink 30 (described later) disposed on the inner circumferential side of the first belt 21. ing. In this embodiment, as an example, the pressure roller 26e is provided on the upstream side of the cooling nip portion T4, and the pressure roller 26f is provided on the downstream side of the cooling nip portion T4 with respect to the recording material conveyance direction (arrow R direction). These pressure rollers 26e and 26f press the second belt 25 with a pressure of, for example, 4.9 N (0.5 kgf), and the first belt 21 is securely brought into contact with the heat sink 30 via the second belt 25. I'm letting you do it.

Although an example in which both the first belt 21 and the second belt 25 are driven is shown here, the present invention is not limited to this. For example, only the first belt 21 may be driven to cause the second belt 25 to follow the first belt 21, or only the second belt 25 may be driven to cause the first belt 21 to follow the second belt 25. It may be made to follow.

<Heat sink>
As described above, the heat sink 30 for cooling the first belt 21 is disposed on the inner peripheral side of the first belt 21. In the case of this embodiment, the heat sink 30 is in contact with the inner peripheral surface of the first belt 21, which is in contact with the recording material S on the side on which a toner image is formed by the fixing device 50 (see FIG. 1). That is, the recording material S on which the toner image has been fixed is held between the first belt 21 and the second belt 25, and is conveyed in the recording material conveyance direction (arrow R direction) as these belts rotate. At this time, the recording material S passes through a cooling nip T4, which is a nip formed by the first belt 21 and the second belt 25 coming into contact with each other. In the case of this embodiment, the first belt 21 forming the cooling nip portion T4 is cooled by the heat sink 30. In order to efficiently cool the recording material S, the heat sink 30 is in contact with the inner circumferential surface of the first belt 21 at a location where a cooling nip portion T4 is formed. When the recording material S passes through the cooling nip T4, its temperature is lowered through the first belt 21, which is cooled by the heat sink 30.

The heat sink 30 as a cooling means is a heat sink made of metal such as aluminum, for example. The heat sink 30 includes a heat receiving part 30a that contacts the first belt 21 and removes heat from the first belt 21, a heat radiating part 30b that radiates heat, and conducts heat from the heat receiving part 30a to the heat radiating part 30b. It has a fin base 30c for. The heat radiation section 30b is formed of a large number of heat radiation fins in order to increase the contact area with air and promote efficient heat radiation. For example, the radiation fins have a thickness of 1 mm, a height of 100 mm, and a pitch of 5 mm, and the fin base 30c has a thickness of 10 mm. Further, in order to forcibly cool the heat sink 30 itself, a cooling fan 40 is provided that blows air toward the heat sink 30 (specifically, the heat radiation section 30b). The air volume of this cooling fan 40 is set to, for example, 2 m ³ /min.

<Belt cleaner>
Further, a belt cleaner 70 serving as a cleaning means is installed on the inner peripheral side of the first belt 21 from downstream of the roller 22c to upstream of the roller 22b (steering roller) in the rotational direction (direction of arrow Q) of the first belt 21. is provided in between. The belt cleaner 70 has a scraper 71 and a storage box 72. Furthermore, in the case of this embodiment, the belt cleaner 70 has a belt attachment guide 73. The belt attachment guide 73 will be described later.

In the case of this embodiment, the scraper 71 contacts the first belt 21 above the heat sink 30 in the gravity direction and from downstream of the roller 22c to upstream of the roller 22b in the rotational direction of the first belt 21. , a belt cleaner 70 is provided. The scraper 71 as a removing member is a film-like sheet member made of, for example, a PET sheet with a thickness of 0.1 mm, and formed to have a length that contacts the first belt 21 at least over the range through which the recording material S passes in the width direction. be. The scraper 71 has flexibility and can follow the movement of the rotating first belt 21 and maintain a state in contact with the first belt 21 . In the case of this embodiment, the scraper 71 is arranged so as to come into contact with the first belt 21 from the counter direction.

The above-mentioned scraper 71 removes adhering matter such as abrasion powder (shaving powder), paper powder, or dust attached to the first belt 21 from the first belt 21 . That is, since the heat sink 30 is in contact with the inner peripheral surface of the first belt 21, the inner peripheral surface of the rotating first belt 21 is rubbed against the heat sink 30. In this case, the first belt 21 is scraped by the heat sink 30, and belt abrasion powder may be generated. This abrasion powder adheres to the inner circumferential surface of the first belt 21 along with paper powder, dust, etc., and tends to accumulate at the upstream end of the heat sink 30. If the amount of accumulated deposits increases and some of the accumulated deposits enters between the heat sink 30 and the first belt 21, thermal resistance increases and the cooling performance of the recording material S may be reduced. .

In order to suppress the generation of such belt abrasion powder, a belt formed of, for example, a polyimide resin containing polytetrafluoroethylene (PTFE) filler is used as the first belt 21. The PTFE filler content is, for example, about 5% by weight. When the polyimide resin of the base material contains a PTFE filler, the frictional resistance with the heat sink 30 decreases, so the first belt 21 containing the PTFE filler has a higher resistance to the heat sink 30 than when the first belt 21 contains no PTFE filler. It becomes difficult to be scraped. However, even if a belt containing PTFE filler is used, abrasion powder may inevitably be generated. Since this abrasion powder contains PTFE filler, it is difficult to adhere to the first belt 21, but even such abrasion powder will adhere to the first belt 21 after passing through the sliding surface between the heat sink 30 and the first belt 21. obtain. Therefore, as the usage time of the first belt 21 becomes longer, the amount of deposits accumulated on the upstream end of the heat sink 30 increases. Therefore, in order to remove the deposits attached to the first belt 21 from the first belt 21, the scraper 71 is provided as described above.

In the belt cleaner 70, a storage box 72 serving as a storage container is arranged below the scraper 71 in the direction of gravity to store deposits scraped off from the inner peripheral surface of the first belt 21 by the scraper 71. . The storage box 72 is open at the upper side in the direction of gravity, and is configured so that the opening can receive deposits on the upstream side in the rotational direction of the first belt 21 from the contact point between the scraper 71 and the first belt 21. Box 72 is located. Note that the scraper 71 is fixed to the storage box 72 with, for example, double-sided tape.

It is preferable that the belt cleaner 70 is provided such that the scraper 71 contacts the inner circumferential surface of the first belt 21 on the side closer to the roller 22c than the center between the rollers 22c and 22b in the rotating direction. That is, in the case of the present embodiment, the roller 22b is a steering roller, and the steering angle is adjusted with steering control, so the first belt 21 moves more in the width direction on the roller 22b side than on the roller 22c side. can be done. If so, if the scraper 71 is brought into contact with the inner peripheral surface of the first belt 21 on the side closer to the roller 22b, the scraper 71 may not contact the inner peripheral surface of the first belt 21 appropriately. There is a possibility that it will be difficult to remove the deposits. In order to avoid this, in this embodiment, the belt cleaner 70 is arranged so that the scraper 71 comes into contact with the inner peripheral surface of the first belt 21 on the side closer to the roller 22c than the roller 22b.

As mentioned above, the first belt 21 is abraded and worn by the heat sink 30, and can also deteriorate over time. Therefore, in this embodiment, the first belt 21 can be replaced by an operator. That is, the first belt 21 is aligned with the rotational axis of the first belt tension rollers (22a to 22d) with respect to the upper frame 62 of the recording material cooling device 20 (see FIGS. 5(a) and 5(b) described later). It is provided so that it can be inserted and removed in any direction. However, when the operator replaces the first belt 21, it is difficult to insert and remove the belt if the first belt 21 and the second belt 25 remain in contact with each other. Therefore, the state is changed to a contact state where the first belt 21 and the second belt 25 are in contact, and a separated state where the first belt 21 and the second belt 25 are separated, in other words, a state where the first belt 21 is loosened. Possibly, the first belt 21 and the second belt 25 are provided so as to be relatively movable.

<Contact/separation mechanism>
Next, a mechanism for relatively moving the first belt 21 and the second belt 25 (referred to as a contact/separation mechanism) will be described. FIGS. 5A and 5B are views of the recording material cooling device 20 viewed from the downstream side in the recording material conveyance direction. Here, the left-right direction in FIG. 3 is the rotational axis direction of the first belt tension rollers (22a to 22d), and the back-front direction in FIG. 3 is the recording material conveyance direction. Here, an example is shown in which one end in the width direction of the upper frame body 62 is swung upward in the direction of gravity with respect to the lower frame body 63; however, the present invention is not limited to this, and one end in the width direction of the lower frame body 63 is It may be configured to swing downward in the direction of gravity with respect to the frame body 62. In the case of this embodiment, the contact/separation mechanism (approach/separation means) mainly includes a hook member 64, a pin 65, and a compression spring 66, which will be described later.

As shown in FIGS. 5A and 5B, the recording material cooling device 20 of this embodiment is roughly divided into an upper frame body 62 and a lower frame body 63. The upper frame body 62 rotatably holds the first belt tensioning rollers (22a to 22d) described above, and also holds a heat sink 30, a belt cleaner 70, and a belt tensioning mechanism section 61, which will be described later. On the other hand, the lower frame body 63 rotatably holds the above-described second belt tension rollers (26a to 26d) and pressure rollers 26e and 26f. These upper frame body 62 and lower frame body 63 swing around a swing shaft 200a provided on a support frame 200 on the back side of the recording material cooling device 20 (on the back side of the main body of the device, on the downstream side in the direction in which the belt is attached). They are connected so that they can swing at the center. The first belt 21 is provided so as to be freely inserted into and removed from the upper frame body 62 from one end in the width direction opposite to the support frame 200 (on the right side in FIG. 5(b)).

A hook member 64 is provided at one end of the upper frame 62 in the width direction, and a pin 65 is provided at the other end of the lower frame 63 in the width direction. A compression spring 66 is disposed on the other end side in the width direction of the lower frame body 63 to bias the upper frame body 62 upward in the direction of gravity. The hook member 64 is provided with a grip part 67, and by holding this grip part 67 and rotating the hook member 64, the operator can engage the hook member 64 with the pin 65, or 64 and the pin 65 may be disengaged from each other. As shown in FIG. 5A, the hook member 64 is engaged with the pin 65, so that the first belt 21 and the second belt 25 are brought into contact with each other. The operator pushes down the upper frame 62 toward the lower frame 63 against the force of the compression spring 66 to engage the hook member 64 with the pin 65.

When replacing the first belt 21, the operator releases the engagement between the hook member 64 and the pin 65. When the engagement between the hook member 64 and the pin 65 is released, the upper frame body 62 is lifted upward by the compression spring 66 and swings as shown in FIG. 5(b). At this time, the first belt tensioning rollers (22a to 22d), the first belt 21, the heat sink 30, the belt cleaner 70, and the belt tensioning mechanism section 61 are moved integrally with the upper frame body 62. The upper frame body 62 is positioned at a predetermined position by being stopped from swinging by a stopper (not shown). In this way, the upper frame body 62 swings relative to the lower frame body 63, so that the first belt 21 and the second belt 25 are in a separated state.

<Belt tension mechanism section>
Returning to FIG. 2, the recording material cooling device 20 of this embodiment is provided with a belt tensioning mechanism section 61 in order to facilitate belt replacement. The belt tensioning mechanism section 61 as a moving means has two positions: a tensioned position (first position, see FIG. 2) where the first belt 21 is stretched, and a non-stretched position (second position) where the first belt 21 is loosened. This is a mechanism for moving the roller 22b (steering roller) between the two positions (see FIG. 6). When the roller 22b is in the second position, the contact pressure on the first belt 21 is smaller than when the roller 22b is in the first position, and the tension of the first belt 21 is loosened.

Here, if the roller 22b is not a steering roller but a so-called tension roller that tensions the first belt 21 with a predetermined tension using a compression spring, the roller 22b is moved between a tensioned position and a non-stretched position. For this purpose, only the roller 22b may be moved. That is, when moving the roller 22b from the tensioned position to the non-stretched position, the roller 22b may be moved against the urging force of the compression spring. On the other hand, when the roller 22b is a steering roller, it has a mechanism for swinging the roller 22b, so in order to move the roller 22b between the tensioned position and the non-stretched position, the roller support mechanism is required. The roller 22b is moved together with the roller 81.

As shown in FIGS. 2 and 6, the belt tension mechanism section 61 includes a holder 61a that holds the roller support mechanism 81, and a cam section 61b formed in, for example, an elliptical shape. The holding body 61a is provided on the upper frame body 62 (see FIG. 5(a)) so as to be swingable about a swing shaft 61c. Further, a cam portion 61b is rotatably provided on the upper frame body 62. The cam portion 61b is rotated so as to reciprocate between the position shown in FIG. 2 and the position shown in FIG. 6 by being operated by an operator. The holding body 61a is then swung by the rotation of the cam portion 61b. Depending on the direction in which the cam portion 61b is rotated by the operator, the roller 22b may move toward the heat sink 30 (toward the inside of the belt) or move away from the heat sink 30 (toward the outside of the belt). do. In this way, the roller 22b is placed in the tension position (FIG. 2) where the first belt 21 is stretched on the first belt tension rollers (22a to 22d), and in the tension position (FIG. 2) where the first belt 21 is stretched on the first belt tension rollers (22a to 22d). 22d) and a relaxed, untensioned position (FIG. 6).

When the roller 22b is in the stretched position, the scraper 71 is in contact with the first belt 21, and the first belt 21 is in contact with the heat sink 30 with a predetermined pressure. In this state, the tension of the first belt 21 is approximately 39.2 N (approximately 4 kgf). On the other hand, when the roller 22b is in the non-stretching position, the first belt 21 is loose with respect to the first belt tensioning rollers (22a to 22d). If the first belt 21 is in a loose state, the operator can prevent the scraper 71 or the heat sink 30 from coming into contact with the first belt 21. That is, when replacing the first belt 21, the operator can remove the old belt from the upper frame body 62 without contacting the scraper 71 or the heat sink 30. Then, the operator can attach a new belt to the upper frame body 62 by passing it over the first belt tension rollers (22a to 22d).

The specific operation of the belt tensioning mechanism section 61 will be explained using FIG. 6. As shown in FIG. 6, the operator holds a knob (not shown) and rotates the cam part 61b counterclockwise (see arrow C), so that the holder 61a swings around the swing shaft 61c under its own weight. It moves downward while contacting the cam portion 61b. In the case of this embodiment, the side surface 30d of the heat sink 30 serves as a stopper for the cam portion 61b, so that the rotation of the cam portion 61b is stopped there. In this way, the roller 22b is moved from the tensioned position d to the non-stretched position e.

The position of the roller 22b in the non-stretching position e is inside the first belt 21 than the position of the roller 22b in the tensioning position d, and is closer to the heat sink 30 so to speak. To achieve this, the holding body 61a and the cam portion 61b, including the swing shaft 61c, are provided on the upper frame body 62 (FIG. 5(a)). When the roller 22b moves to the non-tensioned position e and separates from the first belt 21, the tension on the first belt 21 is released, allowing the operator to pull out the loosened first belt 21 and replace the belt. become.

After attaching the new first belt 21 to the upper frame body 62, the operator rotates the cam portion 61b clockwise. Then, the holding body 61a is lifted by the cam portion 61b and moved upward with the swing axis 61c as the center of swing. The rotation of the cam portion 61b is stopped by contacting a stopper portion 61d formed on the opposite side of the swing shaft 61c of the holding body 61a. In this way, the roller 22b is moved from the non-stretched position e to the stretched position d.

Note that when the roller 22b is not in the tension position d, the operator cannot push down the upper frame body 62 toward the lower frame body 63, and the contact between the first belt 21 and the second belt 25 occurs. It is preferable to prevent this from happening.

<Edge sensor>
Next, the end sensor 90 will be explained using FIGS. 6 to 8. The end sensor 90 as a position detection means includes a belt following member 91, a sensor flag 92, and a plurality of optical sensors (not shown). As shown in FIG. 7, the sensor flag 92 is supported by the sensor support plate 95 so as to be swingable in accordance with the movement of the first belt 21 when the first belt 21 moves in the width direction. The sensor support plate 95 is attached to the above-mentioned support frame 200.

As shown in FIGS. 7 and 8, the sensor flag 92 is, for example, a fan-shaped column member, and has a plurality of openings 92a and a plurality of detected portions 92b formed in an arcuate outer peripheral surface. A plurality of optical sensors (not shown) are fixed to the sensor support plate 95 so as to face the outer peripheral surface from the inside of the sensor flag 92 and to be arranged at predetermined intervals along the swinging direction of the sensor flag 92. has been done. As the sensor flag 92 swings with respect to the sensor support plate 95, the positional relationship between the plurality of optical sensors and the detected portion 92b (or opening 92a) changes, and the light receiving state of each optical sensor can be switched. . Specifically, switching is performed between a detection state in which the optical sensor detects the detected portion 92b and a non-detection state in which the optical sensor faces the opening 92a and does not detect the detected portion 92b. The end position of the first belt 21 can be detected by a combination of the detection state and non-detection state of each of the optical sensors.

The sensor flag 92 described above is provided with a belt following member 91 . The belt following member 91 is, for example, a rod-shaped member provided so as to extend downward in the direction of gravity from the sensor flag 92. The belt following member 91 is biased by a coil spring (not shown) toward the opposite side of the mounting direction of the first belt 21 (the direction intersecting the rotational direction, the direction of arrow X in FIG. 7), and During rotation, it is always in contact with the width direction end portion (the mounting direction tip 21a) of the first belt 21. Therefore, when the first belt 21 moves in the width direction, the belt following member 91 moves to follow the movement of the first belt 21 while maintaining the contact state with the first belt 21. According to the movement of the belt following member 91, the sensor flag 92 swings relative to the sensor support plate 95.

In this embodiment, as shown in FIG. 6, the scraper 71 contacts the inner peripheral surface of the first belt 21 on the side closer to the roller 22c than the roller 22b in the rotation direction (arrow Q direction) of the first belt 21. The belt cleaner 70 is arranged as shown in FIG. Then, the end sensor 90 is set so that the belt following member 91 contacts the distal end 21a (see FIG. 7) of the first belt 21 in the mounting direction downstream of the contact point where the scraper 71 contacts the first belt 21. is arranged. In such a case, compared to the case where the end sensor 90 is arranged so that the belt following member 91 contacts the front end 21a of the first belt 21 in the mounting direction on the upstream side of the contact point of the scraper 71, the first belt This is preferable because it makes it easier to attach the item 21.

<Belt installation guide>
The belt cleaner 70 is provided with a belt attachment guide 73 as a guide member. The belt attachment guide 73 is, for example, a plate-shaped member, and is fixed to the storage box 72. The belt attachment guide 73 will be explained using FIGS. 6 to 10(b) and FIG. 10(c) showing a comparative example. Note that FIG. 7 shows a state in which the first belt 21 is attached, and FIGS. 8 and 9 show a state in which the first belt 21 is not attached. Moreover, the dotted line shown in FIG. 9 indicates the position of the leading end 21a of the first belt 21 in the mounting direction when the first belt 21 is mounted.

As shown in FIG. 6, the belt attachment guide 73 is arranged in a storage box so as to extend in the direction of rotation of the first belt 21 (arrow Q direction) in the opposite direction to the scraper 71, that is, toward the belt following member 91. 72. Further, the belt attachment guide 73 is provided in the storage box 72 so that the tip (downstream end 73c) on the downstream side in the rotational direction is located above the lower end 91a in the gravity direction of the belt following member 91 in the gravity direction. The belt mounting guide 73 is preferably provided so that a portion thereof overlaps the belt following member 91 when viewed from the mounting direction of the first belt 21 (width direction, rotational axis direction of the roller 22c).

Furthermore, it is preferable that the belt attachment guide 73 is provided so as to be inclined in the rotational direction of the first belt 21 so that the downstream end 73c is located above the upstream side in the direction of gravity. Since the belt mounting guide 73 is inclined, the contact range between the belt mounting guide 73 and the inner peripheral surface of the first belt 21 can be narrowed when the first belt 21 is mounted, thereby reducing the sliding resistance when the belt is mounted. This prevents the first belt 21 from being easily damaged. In order to prevent the first belt 21 from being easily damaged, the downstream end 73c of the belt mounting guide 73 is preferably formed into a curved shape such as rounded.

As shown in FIG. 7, the first belt 21 is rotatably mounted between the sensor support plate 95 and the belt mounting guide 73 (see FIG. 8). Then, the first belt 21 is in a stretched state, and the distal end 21a in the mounting direction is brought into contact with the belt following member 91, and the inner peripheral surface is brought into contact with the scraper 71.

As shown in FIG. 10(a), the belt attachment guide 73 contacts the inner circumferential surface of the first belt 21 when the first belt 21 is loosened. When the first belt 21 is worn by the worker, the belt attachment guide 73 comes into contact with the inner peripheral surface of the first belt 21, so that the first belt 21 contacts the belt following member 91 while being supported from below in the direction of gravity. You will be guided to the location where you will be placed. In order to make this possible, in this embodiment, the above-mentioned belt attachment guide 73 is provided in the storage box 72. Note that, as shown in FIG. 10(b), when the first belt 21 is stretched, the belt attachment guide 73 does not contact the inner peripheral surface of the first belt 21. This is to prevent the inner peripheral surface of the first belt 21 from being rubbed by the belt mounting guide 73 when the first belt 21 rotates.

In addition, in order to reliably guide the first belt 21 toward the belt following member 91 when the belt is attached, the belt attachment guide 73 is placed in the storage box 72 so as to extend in the width direction of the first belt 21, as shown in FIG. It is located along. The belt mounting guide 73 is arranged so that, in the mounting direction (arrow X direction), the downstream end 73b is located near the belt following member 91, and the upstream end 73a is located upstream of the upstream end 71a of the scraper 71. Preferably, it extends in the width direction. In this way, the operator can attach the first belt 21 while being supported by the belt attachment guide 73 from the start to the completion of attachment of the first belt 21, so that the operator can place the first belt 21 at an appropriate position where it contacts the belt following member 91. can be easily attached to.

Here, a comparative example in which the belt attachment guide 73 is not provided is shown in FIG. 10(c). In the case of the comparative example shown in FIG. 10(c), the tip 21a in the mounting direction of the first belt 21 (see FIG. 7) slips below the belt following member 91 in the direction of gravity, and the end in the width direction of the first belt 21 (in the mounting direction There is a possibility that the tip end 21a) may not come into contact with the belt following member 91. That is, as described above, when the rollers 22b are moved inward of the belt, the first belt 21 is moved inward in a relaxed state in the mounting direction. At this time, a part of the first belt 21 tends to hang down below the gravity direction lower end 91a of the belt following member 91, and the first belt 21 may be attached as it is. In this state, when the roller 22b is moved outward of the belt, that is, when the first belt 21 is stretched, the lower end 91a of the belt following member 91 in the gravity direction comes into contact with the upper surface of the first belt 21, and The widthwise end portion of one belt 21 does not contact the belt following member 91. In this state, the end position of the first belt 21 cannot be detected by the end sensor 90, and the first belt 21 and the end sensor 90 may be damaged.

In contrast, in this embodiment, the above-mentioned belt attachment guide 73 is provided in the storage box 72. The belt attachment guide 73 prevents a portion of the first belt 21 from hanging below the lower end of the belt following member 91 in the direction of gravity when the belt is attached, and ensures that the first belt 21 is directed toward the belt following member 91. invite. This allows the operator to easily attach the first belt 21 to an appropriate position in contact with the belt following member 91 without damaging or deforming the scraper 71 or the first belt 21 when attaching the belt. It becomes like this.

<Other embodiments>
Note that in the embodiment described above, the belt tensioning mechanism section 61 is not provided on the second belt 25 side where the heat sink 30 and the scraper 71 are not arranged, but the belt tensioning mechanism section 61 is also provided on the second belt 25 side. It may be provided. That is, the second belt 25, which is not provided with the heat sink 30, wears and deteriorates relatively slowly compared to the first belt 21, but it wears out as it is used and also deteriorates over time. , the second belt 25 may be loosened and replaced.

In the above-described embodiment, the recording material cooling device 20 is provided in the main body 100A of the image forming apparatus 100 as an example (see FIG. 1), but the present invention is not limited to this. For example, the recording material cooling device 20 may be provided outside the apparatus main body 100A. FIG. 11 shows an example in which the recording material cooling device 20 is provided outside the apparatus main body 100A.

As shown in FIG. 11, an external cooling unit 101 as an external cooling device is connected to the apparatus main body 100A. The external cooling unit 101 is configured to be connectable to the image forming apparatus 100 as one of peripheral devices (referred to as an option unit or the like) that can be retrofitted to expand the functions of the image forming apparatus 100. The external cooling unit 101 is provided to cool the recording material S discharged from the image forming apparatus 100 and lower the temperature of the recording material S, which is higher than before fixing, to a predetermined temperature or less. The external cooling unit 101 includes the recording material cooling device 20 described above for cooling the recording material S.

The recording material S cooled by the external cooling unit 101 is discharged from the external cooling unit 101 by the discharge roller 85 and stacked on the discharge tray 120 . The discharge tray 120 is provided to be detachably attached to the external cooling unit 101 and the image forming apparatus 100. That is, the discharge tray 120 is attached to the image forming apparatus 100 when the external cooling unit 101 is not connected to the image forming apparatus 100 (see FIG. 1). Then, when the external cooling unit 101 is connected to the image forming apparatus 100, it is removed from the image forming apparatus 100 by an operator and replaced with the external cooling unit 101. Note that a plurality of external cooling units 101 may be connected as peripheral devices. By increasing the number of connected external cooling units 101, an operator can easily improve the cooling capacity of the recording material S in the existing image forming apparatus 100.

20... Recording material cooling device, 21... Belt (first belt), 22b... Second roller (roller), 22c... First roller (roller), 25... Rotating body (second belt), 30... Cooling means (heat radiation) plate, heat sink), 61... Moving means (belt tensioning mechanism), 64... Approaching and separating means (hook member), 65... Approaching and separating means (pin), 66... Approaching and separating means (compression spring), 70... Cleaning means (belt cleaner), 71...Removal member (scraper), 72...Accommodation container (accommodation box), 73...Guiding member (belt attachment guide), 90...Position detection means (end sensor), 91...Following member (belt tracking) 400... Steering mechanism, S... Recording material, T4... Nip part (cooling nip part)

Claims (9)

a rotatable endless belt; a first roller that stretches the belt; a second roller that stretches the belt together with the first roller; and a roller that contacts an inner circumferential surface of the belt to cool the belt. A recording material cooling device that cools a recording material on which a toner image is fixed by heating,
a removal member that comes into contact with the inner circumferential surface of the belt in a width direction intersecting the rotational direction of the belt and removes deposits attached to the inner circumferential surface; and a removal member that accommodates the deposits removed by the removal member. a cleaning means having a storage container for cleaning;
position detection means having a following member that contacts an end of the belt and follows the movement of the belt in the width direction, and detects the position of the end of the belt according to the position of the following member;
moving means for moving the second roller between a first position where the belt is stretched and a second position where the belt is detachably loosened in the width direction;
A guide provided in the storage container that supports the belt to be mounted from below in the direction of gravity and guides it toward the following member so that the leading end of the belt in the mounting direction contacts the following member when the belt is mounted. comprising a member;
A recording material cooling device characterized by: The guide member is provided so that a portion thereof overlaps with the follower member when viewed from the mounting direction.
The recording material cooling device according to claim 1, characterized in that: The guide member extends in the width direction so that the upstream end is located upstream of the upstream end of the removal member in the mounting direction.
3. The recording material cooling device according to claim 2. a steering mechanism that swings the second roller relative to the first roller and reciprocates the belt in the width direction;
The removal member contacts the inner circumferential surface of the belt on a side closer to the first roller than the second roller.
The recording material cooling device according to any one of claims 1 to 3. The following member contacts the end of the belt on the downstream side in the rotational direction of the contact point where the removal member contacts the belt.
5. The recording material cooling device according to claim 4. The guide member is inclined such that the downstream end is located higher in the direction of gravity than the upstream side in the rotation direction.
6. The recording material cooling device according to claim 5. a rotating body that comes into contact with the outer peripheral surface of the belt and forms a nip portion for cooling the recording material on which the toner image is formed while nipping and conveying it;
comprising a contact/separation means capable of changing between a state in which the belt and the rotating body are in contact with each other and a state in which the belt and the rotating body are separated;
The moving means is capable of moving the second roller when the belt and the rotating body are separated from each other.
The recording material cooling device according to any one of claims 1 to 6. The rotating body is an endless belt.
8. The recording material cooling device according to claim 7. The cooling means is a heat sink that radiates heat by contacting the belt,
The recording material cooling device according to any one of claims 1 to 8.

Images