Cooling device

Abstract

To provide a cooling device capable of removing deposits adhered to a belt for nipping and conveying a recording material for cooling purposes.SOLUTION: A recording material cooling device 20 comprises: an endless first belt 21 that rotates; and an endless second belt 25 that forms a cooling nip T4 with the first belt 21 and rotates to nip a recording material at the cooling nip T4 and convey the recording material. A heat sink 30 is disposed on the first belt 21 side. The heat sink 30 abuts the first belt 21 to cool the first belt 21. On the other hand, a belt cleaning device 90 is disposed on the second belt 25 side on which the heat sink 30 is not disposed. The belt cleaning device 90 rubs the second belt 25 and removes deposits adhered to the second belt 25 in the second belt 25 to which deposits such as toner and wax from the recording material easily adhere by not being cooled by the heat sink 30.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a cooling device for cooling a recording material that has passed through a fixing device that fixes a toner image by heating. Place Regarding. [Background technology]

[0002] In an electrophotographic image forming apparatus, a toner image formed on a recording material such as paper is heated and pressurized by a fixing device to fix the toner image to the recording material. The toner image is fixed by sandwiching and conveying the recording material between a fixing roller heated by a heater or the like and a pressure roller pressed against the fixing roller. Since the recording material is heated when the toner image is fixed, the temperature of the recording material conveyed from the fixing device is likely to be higher than that before fixing. After the toner image is fixed, as many recording materials conveyed at a temperature higher than a predetermined temperature are stacked on the stacking section, the stacked recording materials may stick to each other due to the toner. In order to prevent the recording materials from sticking to each other when stacked, a cooling device is provided that cools the recording material conveyed from the fixing device after the toner image is fixed in order to lower the temperature of the recording material after the toner image is fixed (Patent Document 1). The cooling device described in Patent Document 1 is a belt cooling type cooling device in which one of a pair of conveying belts that sandwich and convey the recording material conveyed from the fixing device is cooled by a heat sink, and the temperature of the recording material is lowered through the cooled conveying belt. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5272424 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, image forming apparatuses are required to be multimedia compatible so that they can handle various types of recording materials, such as plain paper, thick paper, rough paper (paper with a rough surface), textured paper (embossed paper, etc.), and coated paper. Recently, toners containing wax that melt at low temperatures have been used in order to fix the toner to the recording material even at low temperatures. When such toners are used to form images, the toner and wax may transfer from the recording material and adhere to the belt of the cooling device. In particular, when printing on thick paper or coated paper, which have poorer thermal conductivity than plain paper, the adhesion of the toner and wax to the belt is noticeable. The toner and wax that adhere to the belt may cause image unevenness or image stains on the recording material that passes through the cooling device thereafter, and if paper powder or dust adheres to the wax, it may cause the recording material to become dirty.

[0005] The present invention has been made in view of the above problems, and provides a cooling device that can remove deposits that have adhered to a belt that nip and conveys the recording material for cooling, in a configuration that cools the recording material that has passed through a fixing device using a belt cooling method. Place The purpose is to provide. [Means for solving the problem]

[0006] A cooling device according to an embodiment of the present invention includes a first belt, a second belt that contacts the first belt to form a nip portion with the first belt, a plurality of tension rollers that tension the second belt, and a cooling roller that tensions the first belt. Contact with the inner surface of The above one Belt By cooling a cooling means for cooling the recording material passing through the nip portion; a first cleaning means for contacting an outer circumferential surface of the first belt and cleaning the outer circumferential surface of the first belt; Contacting the outer circumferential surface of the second belt and cleaning the outer circumferential surface of the second belt. Second and a cleaning means, Second The cleaning means has a rubbing member that rubs against the second belt, and the rubbing member rubs against the second belt at a position facing a predetermined roller among the plurality of tension rollers via the second belt. Effect of the Invention

[0007] According to the present invention, in a configuration in which the recording material that has passed through the fixing device is cooled by the belt cooling method, it is possible to remove any deposits that have adhered to the belt that nip and transports the recording material for cooling. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing a configuration of an image forming apparatus according to an embodiment of the present invention. [Diagram 2] FIG. [Diagram 3] FIG. 2 is a schematic diagram showing a recording material cooling device according to the first embodiment. [Figure 4] FIG. 4 is a schematic diagram illustrating the arrangement of a belt cleaning device. [Diagram 5] FIG. 11 is a schematic diagram showing a recording material cooling device using another belt cleaning device. [Figure 6] FIG. 11 is a schematic diagram showing a recording material cooling device according to a second embodiment. [Figure 7] FIG. 1 is a schematic diagram illustrating an embodiment of an image forming system. [Figure 8] FIG. 11 is a schematic diagram showing another embodiment of an image forming system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [First embodiment] <Image forming device> A schematic configuration of an image forming apparatus according to the present embodiment will be described with reference to FIGS. 1 and 2. The image forming apparatus 100 shown in FIG. 1 is a tandem-type full-color printer of an electrophotographic system. The image forming apparatus 100 has image forming units PY, PM, PC, and PK that form images of yellow, magenta, cyan, and black, respectively. The image forming apparatus 100 forms a toner image on a recording material S in response to an image signal from an original reading device (not shown) connected to the apparatus main body 100A or an external device such as a personal computer connected to the apparatus main body 100A so as to be able to communicate with the apparatus main body 100A. Examples of the recording material S include various types of sheet materials such as plain paper, thick paper, rough paper, textured paper, coated paper, and other papers, plastic films, and cloth.

[0010] As shown in FIG. 1, the image forming units PY, PM, PC, and PK are arranged in line in the moving direction of an intermediate transfer belt 8 in the apparatus main body 100A (inside the apparatus main body). The intermediate transfer belt 8 is stretched around a number of rollers and configured to run in the direction of arrow R2. The intermediate transfer belt 8 carries and transports the toner image that has been primarily transferred. A secondary transfer roller 10 is arranged at a position facing the roller 9 that stretches the intermediate transfer belt 8 across the intermediate transfer belt 8, forming a secondary transfer unit T2 that transfers the toner image on the intermediate transfer belt 8 to a recording material S. A fixing device 11 is arranged downstream of the secondary transfer unit T2 in the recording material transport direction.

[0011] A cassette 12 containing a recording material S is disposed at the bottom of the image forming apparatus 100. The recording material S is conveyed by a conveying roller 13 from the cassette 12 toward a registration roller 14 along a conveying path 600 that forms a path for the recording material S within the apparatus main body 100A. Thereafter, the registration roller 14 starts to rotate in synchronization with a toner image formed on the intermediate transfer belt 8 as described later, so that the recording material S is conveyed along the conveying path 600 to the secondary transfer portion T2. ​​Although only one cassette 12 is shown here, a plurality of cassettes 12 may be disposed so as to be able to contain recording materials S of different sizes and thicknesses. In this case, the recording material S is selectively conveyed from one of the plurality of cassettes 12 to the conveying path 600. In addition, the recording material S is not limited to the recording material S contained in the cassette 12, but the recording material S placed on a manual feed portion (not shown) may be conveyed to the conveying path 600. In this embodiment, the transport path 600 has a reversing transport section 600a that, during double-sided printing, reverses the recording material S cooled by the recording material cooling device 20 and transports it again to the image forming sections PY, PM, PC, and PK.

[0012] <Image forming section> The four image forming units PY, PM, PC, and PK included in the image forming apparatus 100 have substantially the same configuration, except for the different developing colors. Therefore, the image forming unit PK will be described here as a representative, and descriptions of the other image forming units PY, PM, and PC will be omitted.

[0013] 2, the image forming unit PK is provided with a cylindrical photosensitive drum 1 as a photosensitive member. The photosensitive drum 1 is driven to rotate in the direction of arrow R1. Around the photosensitive drum 1, a charging device 2, an exposure device 3, a developing device 4, a primary transfer roller 5, and a drum cleaning device 6 are arranged.

[0014] A process of forming, for example, a full-color image by the image forming apparatus 100 will be described. First, when an image forming operation is started, the surface of the rotating photosensitive drum 1 is uniformly charged by the charging device 2. The charging device 2 is, for example, a corona charger that irradiates charged particles associated with corona discharge to charge the photosensitive drum 1 to a uniform negative polarity dark potential. Next, the photosensitive drum 1 is scanned and exposed by a laser beam L corresponding to an image signal emitted from an exposure device 3. As a result, an electrostatic latent image corresponding to the image signal is formed on the surface of the photosensitive drum 1. The electrostatic latent image formed on the photosensitive drum 1 is visualized by the toner (developer) contained in the developing device 4, becoming a visible image.

[0015] The toner image formed on the photosensitive drum 1 is primarily transferred to the intermediate transfer belt 8 at a primary transfer section T1 formed between the photosensitive drum 1 and a primary transfer roller 5 arranged with the intermediate transfer belt 8 sandwiched therebetween. At this time, a primary transfer bias is applied to the primary transfer roller 5. Toner remaining on the surface of the photosensitive drum 1 after the primary transfer is removed by a drum cleaning device 6.

[0016] Such an operation is performed in sequence at each of the yellow, magenta, cyan, and black image forming units PY to PK, and the four color toner images are superimposed on the intermediate transfer belt 8. Thereafter, in accordance with the timing of the formation of the toner images, the recording material S stored in the cassette 12 is conveyed to the secondary transfer unit T2. Then, a secondary transfer bias is applied to the secondary transfer roller 10, so that the full-color toner images formed on the intermediate transfer belt 8 are secondarily transferred to the recording material S all at once.

[0017] The recording material is then transported to the fixing device 11. The fixing device 11 has a fixing roller 11a as a heating section arranged to rotate freely, and a pressure roller 11b as a pressure section that rotates while being in pressure contact with the fixing roller 11a and can nip and transport the recording material S together with the fixing roller 11a. The fixing roller 11a is rotated at a predetermined rotation speed (e.g., 400 mm / sec) by a motor (not shown) while being in pressure contact with the pressure roller 11b. A halogen heater 11c as a heat source is arranged within the fixing roller 11a, and the fixing device 11 can heat the recording material S by raising the surface temperature of the fixing roller 11a by the halogen heater 11c.

[0018] The fixing device 11 heats and pressurizes the conveyed recording material S, by nipping and conveying the recording material S on which the toner image has been formed, in a fixing nip T3 formed by the fixing roller 11a and the pressure roller 11b, thereby fixing the toner image to the recording material S. That is, the toner of the toner image formed on the recording material S by the heating and pressure is melted and mixed, and fixed to the recording material S as a full-color image. In this manner, a series of image forming processes is completed. Then, the recording material S that has passed through the fixing device 11 is conveyed from the fixing device 11 to the recording material cooling device 20. The recording material cooling device 20, which serves as a cooling device, cools the recording material S. The recording material cooling device 20 will be described later (see FIG. 3).

[0019] <Control Unit> As shown in Fig. 1, the image forming apparatus 100 includes a control unit 300. The control unit 300 performs various controls of the image forming apparatus 100, such as an image forming operation, and includes a CPU 301 (Central Processing Unit) and a memory 302, such as a ROM, a RAM, or a hard disk device. The memory 302 stores various programs, such as an image forming job for forming an image on a recording material S, and various data. The control unit 300 can execute various programs stored in the memory 302, and can operate the image forming apparatus 100 by executing the various programs. The memory 302 can also temporarily store arithmetic processing results associated with the execution of the various programs.

[0020] The control unit 300 can execute, as the image forming job, a single-sided printing job in which a toner image is fixed only on one side of the recording material S, and a double-sided printing job in which a toner image is fixed on both sides of the recording material S. In the case of a single-sided printing job, the recording material S cooled by the recording material cooling device 20 is discharged by the paper discharge roller 15 to the outside of the apparatus main body 100A (outside the apparatus main body) and is stacked on the stacking unit 60. On the other hand, in the case of a double-sided printing job, the recording material S cooled by the recording material cooling device 20 is reversed by the reverse conveying unit 600a, so that the front and back of the recording material S are swapped. The reversed recording material S is returned to the conveying path 600 and conveyed through the conveying path 600 toward the registration roller 14, and conveyed by the registration roller 14 to the secondary transfer unit T2 with the unprinted side facing the intermediate transfer belt 8 side. In the secondary transfer unit T2, the full-color toner image formed on the intermediate transfer belt 8 is secondarily transferred collectively to the recording material S (back side). Thereafter, the toner image is fixed on the recording material S by the fixing device 11, and the recording material is cooled by the recording material cooling device 20. The cooled recording material S is discharged outside the apparatus main body 100A and stacked on the stacking unit 60.

[0021] <Recording material cooling device> Next, the recording material cooling device 20 of the first embodiment will be described with reference to FIG. 3. The recording material cooling device 20 of the present embodiment is a belt-cooling type cooling device. As shown in FIG. 3, the recording material cooling device 20 has an endless first belt 21 and an endless second belt 25 that conveys the first belt 21 and the recording material S by pinching them together. For example, the first belt 21 and the second belt 25 are made of high-strength polyimide, and are set to a thickness of 100 μm and a circumferential length of 942 mm. The recording material cooling device 20 also has a heat sink 30 that cools the first belt 21. In the case of the present embodiment, the heat sink 30 is in contact with the first belt 21 that contacts the recording material S on the side on which the toner image is formed by the fixing device 11. Note that the first belt 21 is not limited to being cooled by the heat sink 30. For example, a belt fan capable of cooling the first belt 21 by blowing air to the first belt 21 may be used.

[0022] The first belt 21 is wound around a plurality of first belt tension rollers 22a to 22e, and at least one of the first belt tension rollers 22a to 22e is rotated by a drive motor 500. In this embodiment, the first belt tension roller 22d rotated by the drive motor 500 corresponds to a drive roller that drives the first belt 21. As a result, the first belt 21 rotates in the direction of the arrow B in the figure. On the other hand, the second belt 25 is wound around a plurality of second belt tension rollers 26a to 26e and abuts against the first belt 21. Then, at least one of the second belt tension rollers 26a to 26e is rotated by the drive motor 500. In this embodiment, the second belt tension roller 26d rotated by the drive motor 500 corresponds to a drive roller that drives the second belt 25. In this way, the first belt 21 and the second belt 25 are rotated in the same direction in the cooling nip T4 by the drive motor 500, which is the same drive source, via a drive gear (not shown) or the like.

[0023] In this embodiment, both the first belt 21 and the second belt 25 are driven by the drive motor 500, but this is not limiting. For example, only the first belt 21 may be driven by the drive motor 500 to make the second belt 25 follow the first belt 21, or the second belt 25 may be driven by the drive motor 500 to make the first belt 21 follow the second belt 25.

[0024] Further, any one of the first belt tension rollers 22a to 22e and any one of the second belt tension rollers 26a to 26e are steering rollers provided to control the deviation of the first belt 21 and the second belt 25, respectively. In the case of this embodiment, for example, the first belt tension roller 22b and the second belt tension roller 26b are steering rollers. These steering rollers (22b, 26b) are biased by a spring 221 so as to press the first belt 21 and the second belt 25 from the inner circumferential side toward the outer side so that the tension of the first belt 21 and the second belt 25 becomes about 39.2 N (about 4 kgf). The steering rollers (22b, 26b) turn a steering angle with the center of the rotation axis direction (longitudinal direction) as a pivot point, thereby controlling the meandering of the first belt 21 and the second belt 25.

[0025] Moreover, pressure rollers 26f, 26g that pressurize the second belt 25 toward the heat sink 30 are provided on the inner peripheral side of the second belt 25. The pressure rollers 26f, 26g pressurize the second belt 25 with a pressure of, for example, 9.8 N (1 kgf), thereby reliably bringing the first belt 21 into contact with the heat sink 30 (a heat receiving portion 30a described later in detail) via the second belt 25.

[0026] The recording material S that has passed through the fixing device 11 is sandwiched between the first belt 21 and the second belt 25, and is conveyed in the conveying direction (the direction of the arrow C in the figure) according to the rotation of these belts. At that time, the recording material S passes through a cooling nip T4, which is a nip portion formed by the contact between the first belt 21 and the second belt 25. In the case of this embodiment, the first belt 21 is cooled by a heat sink 30. The heat sink 30 is arranged so as to contact the inner surface of the first belt 21 at a location that forms the cooling nip T4 in order to efficiently cool the recording material S. The recording material S is cooled through the first belt 21 when passing through the cooling nip T4. For example, if the temperature of the recording material S is about 90° C. before passing through the recording material cooling device 20, the recording material S is cooled so that the temperature becomes about 60° C. after passing through the recording material cooling device 20. As the recording material S is cooled, the toner on the recording material S is cooled and fixed.

[0027] The heat sink 30 as a cooling means is a heat dissipation plate made of a metal such as aluminum. The heat sink 30 has a heat receiving portion 30a for contacting the first belt 21 to take heat from the first belt 21, a heat dissipation portion 30b for dissipating heat, and a fin base 30c for conducting heat from the heat receiving portion 30a to the heat dissipation portion 30b. The heat dissipation portion 30b is formed of a large number of heat dissipation fins to increase the contact area with the air and promote efficient heat dissipation. For example, the heat dissipation fins are set to a thickness of 1 mm, a height of 100 mm, and a pitch of 5 mm, and the fin base 30c is set to a thickness of 10 mm. In addition, a cooling fan 40 is provided to blow air toward the heat sink 30 (more specifically, the heat dissipation portion 30b) in order to forcibly cool the heat sink 30 itself. The air volume of this cooling fan 40 is, for example, 2 m 3 / min. The cooling of the heat sink 30 is not limited to the cooling fan 40. Alternatively, the heat sink 30 may be cooled by blowing air from outside the device main body 100A through a duct into the device main body 100A, or a pipe through which a refrigerant is circulated may be provided in the heat sink 30, and the heat sink 30 may be cooled by the refrigerant passing through the pipe.

[0028] Incidentally, for example, in double-sided printing, as described above, the recording material S, on whose first surface a toner image has been fixed by the fixing device 11, passes through the fixing device 11 again with a toner image formed on the second surface opposite to the first surface. That is, the recording material S passes through the fixing device 11 twice. In this case, when the recording material S passes through the fixing device 11 for the second time, the toner image previously fixed on the recording material S is heated together with the toner image subsequently formed on the recording material S, and melted again. As a result, the recording material S in double-sided printing is conveyed to the recording material cooling device 20 with both the toner images on the first and second surfaces in a soft state. Thereafter, the toner softened by passing through the fixing device 11 is cooled and solidified by a drop in temperature, and is separated from the first belt 21 and the second belt 25 and fixed to the recording material S.

[0029] Here, the second belt 25 of the recording material cooling device 20 is cooled by the heat sink 30 via the first belt 21, and thus the heat accumulated in the belt is less likely to be removed than in the first belt 21, which is directly cooled by the heat sink 30. Therefore, when the recording material S during double-sided printing is conveyed to the cooling nip T4 of the recording material cooling device 20, the surface in contact with the second belt 25 is less likely to be cooled (heat is less likely to be removed) than the surface in contact with the first belt 21. As a result, the toner image on the surface in contact with the second belt 25 is less likely to solidify than the toner image on the surface in contact with the first belt 21, and the toner on the recording material S and wax separated from the toner are more likely to adhere to the second belt 25 as deposits than the first belt 21. The deposits thus attached to the second belt 25 need to be removed because they may cause image unevenness or image stains on the recording material S that is subsequently cooled, or may stain the recording material S.

[0030] <Belt cleaning device> Therefore, in order to remove the toner, wax, and other deposits from the second belt 25, the recording material cooling device 20 of this embodiment is provided with a belt cleaning device 90 as a cleaning means.

[0031] 3, the belt cleaning device 90 is a brush-type cleaning device having a housing 93, a fur brush roller 91, and a scraper 92. The fur brush roller 91 and the scraper 92 are provided inside the housing 93. The fur brush roller 91 as a rubbing member (rubbing rotor) has nylon fibers planted in a brush shape on the outer circumferential surface of a conductive roller, and this fur brush abuts against the outer circumferential surface of the second belt 25 while maintaining a predetermined penetration amount.

[0032] The fur brush roller 91 is rotated by the above-mentioned drive motor 500 in the opposite direction (arrow Y direction in the figure) to the rotation direction of the second belt 25 on the contact surface with the second belt 25, and rubs against the second belt 25. That is, the fur brush roller 91 and at least one of the first belt 21 and the second belt 25 are driven by the drive motor 500, which is the same drive source. The fur brush roller 91 rubs against the second belt 25, thereby collecting the deposits attached to the second belt 25 on the fur brush roller 91 side. As a result, the deposits are removed from the second belt 25. The deposits collected by the fur brush roller 91 are scraped off into the housing 93 by the scraper 92 that contacts the fur brush roller 91 in the counter direction opposite to the rotation direction of the fur brush roller 91. The scraper 92 is a rubber blade formed of a rubber member such as urethane rubber. The housing 93 also serves as a container for storing the scraped off deposits.

[0033] The belt cleaning device 90 may be disposed so as to rub against the second belt 25 at any position, but is preferably disposed so as to rub against the second belt 25 at a position from the downstream end of the cooling nip T4 to half the circumference of the second belt 25 in the rotation direction of the second belt 25. This is because, when the deposits on the second belt 25 pass the position from the downstream end of the cooling nip T4 to half the circumference of the second belt 25, they tend to adhere to the second belt 25 due to cooling, and become difficult to remove. In addition, the belt cleaning device 90 is preferably disposed so as to rub against the second belt 25 at a position where the second belt 25 is sandwiched between a predetermined roller among the second belt tension rollers 26a to 26e. This is because the belt cleaning device 90 can stably rub against the second belt 25 by pressing the second belt 25 against the predetermined roller. In view of the above, in this embodiment, as shown in FIG. 3, the belt cleaning device 90 is disposed opposite the second belt tension roller 26c (corresponding to the predetermined roller) with the second belt 25 interposed therebetween.

[0034] Note that, even if the steering roller (26b) is disposed at a position from the downstream end of the cooling nip T4 to half the circumferential length of the second belt 25, the belt cleaning device 90 is not disposed to face the steering roller (26b). This is because, if the belt cleaning device 90 is disposed to face the steering roller (26b), there is a risk that the steering roller (26b) will not be able to accurately control the deviation of the second belt 25.

[0035] As shown in FIG. 3, the second belt tension roller 26c facing the belt cleaning device 90 may be provided with a heater 510 therein. The heater 510 as a heating means heats the second belt tension roller 26c. When the second belt tension roller 26c is heated, the surface temperature of the second belt 25 partially increases in the vicinity of the rubbing portion heated by the second belt tension roller 26c. This makes it possible to increase the temperature of the deposits such as toner and wax adhering to the second belt 25 before removal by the belt cleaning device 90, making it easier for the belt cleaning device 90 to remove the deposits. That is, the second belt tension roller 26c is heated, thereby improving the ability of the belt cleaning device 90 to remove deposits.

[0036] 4, the belt cleaning device 90 may be disposed opposite the second belt tension roller 26d that functions as a drive roller with the second belt 25 sandwiched therebetween. In this case, the belt cleaning device 90 is disposed immediately after the second belt 25 passes through the cooling nip T4 and before the temperature of the toner, wax, and other deposits on the second belt 25 starts to drop. This makes it easier for the belt cleaning device 90 to remove the deposits. Furthermore, it is preferable to provide a heater 510 in the second belt tension roller 26d so that the temperature of the deposits on the second belt 25 can be increased before the removal by the belt cleaning device 90, since this makes it possible to more reliably remove the deposits on the second belt 25.

[0037] As described above, in this embodiment, the belt cleaning device 90 is disposed on the side of the second belt 25 that is not directly cooled by the heat sink 30, and the second belt 25 is rubbed against the belt cleaning device 90. In this manner, the second belt 25 is not directly cooled by the heat sink 30 and is therefore prone to adhesion of toner, wax, and other adhering matter from the recording material S, so that the adhering matter adhering to the second belt 25 can be removed by the belt cleaning device 90.

[0038] In addition to the above, the belt cleaning device 90 may be, for example, a cleaning blade made of polyurethane rubber that comes into contact with the second belt 25 in the counter direction opposite to the rotation direction of the second belt 25 to mechanically scrape off and remove deposits. The belt cleaning device 90 may also be a so-called web-type belt cleaning device that removes deposits by rubbing a web, which is a cloth-like member, against the second belt 25. A recording material cooling device 20 in which a web-type belt cleaning device is used is shown in FIG. 5.

[0039] The belt cleaning device 90A includes a cloth-like web 901 such as a nonwoven fabric, a payout roller 902 that pays out the web 901, a contact roller 903 that brings the web 901 into contact with the outer peripheral surface of the second belt 25, and a take-up roller 904 that takes up the web 901. The payout roller 902 and the take-up roller 904 are arranged so that the web 901 as a rubbing member (web member) moves in the opposite direction to the rotation direction (the direction of the arrow D in the figure) of the second belt 25. The take-up roller 904 moves the web 901 so as to change the portion of the web 901 that contacts the second belt 25. That is, an unused portion of the web 901 is wound around the payout roller 902, and a used portion of the web 901 is wound around the take-up roller 904. The unused portion of the web 901 is paid out from the payout roller 902 as the used portion is wound around the take-up roller 904 as a moving means by rotating. An unused portion of the web 901 fed from the feed roller 902 is brought into contact with the second belt 25 by the contact roller 903. The web 901 rubs against the second belt 25, thereby removing any deposits on the second belt 25.

[0040] The winding roller 904 is driven by a drive motor 500 that drives at least one of the second belt tension rollers 26a to 26e. That is, the winding roller 904 and at least one of the first belt 21 and the second belt 25 are driven by the drive motor 500, which is the same drive source. However, in this case, as shown in FIG. 5, a drive transmission member such as a clutch 501 is provided to switch between transmission and non-transmission of drive to the winding roller 904. The switching between transmission and non-transmission of drive by the clutch 501 and the like is controlled by the control unit 300 (see FIG. 1). For example, every time the cumulative number of recording materials S on which images have been formed reaches a multiple of 1000 sheets, the control unit 300 temporarily switches the drive transmission by the clutch 501 and the like from non-transmission to transmission, and brings the unused portion of the web 901 into contact with the second belt 25.

[0041] When using a web-type belt cleaning device 90A, a heater 510 may be provided in the contact roller 903 to raise the temperature of the deposits on the second belt 25 so that the deposits are removed by the web 901. The winding roller 904 may be driven by the above-mentioned drive motor 500. In this case, however, a member for adjusting the number of rotations is used so that a predetermined amount of the web 901 is paid out (wound) every predetermined time.

[0042] [Second embodiment] Next, a recording material cooling device 20A of a second embodiment will be described. In the recording material cooling device 20 of the first embodiment described above (see FIG. 3), the recording material S is cooled on the side on which the toner image is formed by the fixing device 11 (the side on which the fixing roller 11a is provided), but this is not limited thereto. For example, the recording material S may be cooled from the side opposite to the side on which the toner image is formed by the fixing device 11. FIG. 6 shows a recording material cooling device 20A that cools the recording material S on the side opposite to the side on which the toner image is formed by the fixing device 11 (the side on which the pressure roller 11b is provided). In the recording material cooling device 20A shown in FIG. 6, the same components as those of the recording material cooling device 20 of the first embodiment are denoted by the same reference numerals, and the description thereof will be simplified or omitted.

[0043] In this embodiment, the heat sink 30 is in contact with the first belt 21 that contacts the recording material S from the side opposite to the side on which the toner image is formed by the fixing device 11. In this case, when the recording material S having low thermal conductivity such as thick paper passes through the cooling nip T4, the side of the recording material S that contacts the second belt 25 is not sufficiently cooled, and there is a risk that a deposit will adhere to the second belt 25.

[0044] Therefore, as shown in FIG. 6, in the recording material cooling device 20A of this embodiment, the belt cleaning device 90 is provided on the second belt 25 side. The belt cleaning device 90 may be disposed so as to rub against the second belt 25 at any position. However, the belt cleaning device 90 is preferably disposed so as to rub against the second belt 25 at any position from the downstream end of the cooling nip T4 to half the circumference of the second belt 25 with respect to the rotation direction of the second belt 25 (the direction of the arrow B in the figure). Also, the belt cleaning device 90 is preferably disposed so as to rub against the second belt 25 at a position where the second belt 25 is sandwiched between a predetermined roller among the second belt tension rollers 26a to 26e. Here, as an example, the belt cleaning device 90 is disposed opposite the second belt tension roller 26c with the second belt 25 sandwiched between them. Also, a heater 510 may be provided in the second belt tension roller 26c where the second belt 25 is sandwiched between the predetermined roller and the second belt 25.

[0045] In this way, even when the first belt 21, which is cooled by the heat sink 30, cools the recording material S from the side opposite to the side on which the toner image is formed by the fixing device 11, the deposits adhering to the second belt 25 can be removed by the belt cleaning device 90.

[0046] In the above-described embodiments, the belt cleaning device 90 is provided only on the second belt 25, but the present invention is not limited thereto. For example, when the recording material S that has passed through the fixing device 11 passes through the recording material cooling device 20 continuously, the cooling performance of the first belt 21 may also be reduced, and the first belt may also become contaminated with toner, wax, or other deposits. In this case, the first belt 21 may also be provided with a belt cleaning device 90 that cleans the outer circumferential surface of the belt, thereby removing the deposits that have adhered to the first belt 21. In this manner, the belt cleaning device 90 may be provided on both the first belt 21 and the second belt 25. Alternatively, the present invention may be provided with a heat sink 30 that contacts the inner circumferential surface of the first belt 21 and another heat sink that contacts the inner circumferential surface of the second belt 25, and a plurality of cleaning means may be provided to clean each of the first belt 21 and the second belt 25.

[0047] In the above-described embodiments, the image forming apparatus 100 has the fixing device 11 and the recording material cooling device 20 in one housing (apparatus main body 100A) as an example, but the present invention is not limited to this. The image forming apparatus may have the image forming units PY, PM, PC, PK, intermediate transfer belt 8, and secondary transfer roller 10 in a first housing, and the fixing device 11 and the recording material cooling device 20 in a second housing different from the first housing, with the first housing and the second housing constituting a single apparatus.

[0048] In the above-described embodiments, the image forming apparatus 100 having the recording material cooling device 20 therein (see FIG. 1) has been described as an example, but the present invention is not limited thereto. For example, as shown in FIG. 7, an external cooling device 101 may be connected to an image forming apparatus 1001 that does not have the recording material cooling device 20 (see FIG. 1) in the apparatus main body 100A. In this way, by making it possible to connect the external cooling device 101 to an image forming apparatus 1001 that does not have the recording material cooling device 20, a user can easily improve the cooling capacity of the existing image forming apparatus 1001 without replacing the existing image forming apparatus 1001. Even when using a recording material S that requires a high fixing temperature such as thick paper, the gloss of the toner image can be made uniform and the sticking of recording materials loaded on the loading unit 60 to each other can be suppressed. In this way, it is possible to easily meet the needs of users who want to improve the cooling capacity of the image forming system 1X. 7, the image forming system 1X includes the image forming apparatus 1001 and the external cooling device 101, which are each installed on an installation surface such as a floor by a plurality of installation units 800. Here, the installation units 800 are casters, installation legs, or the like.

[0049] In addition, as long as the cooling device is provided downstream of the fixing device in the conveying direction of the recording material S in the image forming system, it may have a configuration having a plurality of fixing devices 11, 111, as in the image forming system 1X shown in FIG. 8. That is, as shown in FIG. 8, an external fixing device 700 having a second fixing device 111 may be connected to the outside of an image forming apparatus 1001 having a first fixing device 11. Here, the external fixing device 700 is an optional device that can be selectively connected to the image forming apparatus 1001. The external fixing device 700 is connected to the image forming apparatus 1001 in order to improve the glossiness of the recording material S output from the image forming apparatus 1001 and the discharge speed (the number of recording materials S discharged per unit time) of the recording material S having a large basis weight, such as cardboard, discharged from the image forming apparatus 1001. In this way, when the optional external fixing device 700 is connected to the image forming apparatus 1001, since the image forming apparatus 1001 is provided with a plurality of fixing devices 11, 111, it is required to improve the cooling performance of the image forming apparatus 1001. Even in such a case, according to this embodiment, the external cooling device 101 can be connected to the external fixing device 700, so that it is possible to easily meet the needs of users who wish to improve the cooling performance of the image forming system 1X. [Explanation of symbols]

[0050] 1X: image forming system, 11 (111): fixing device, 11a: heating section (fixing roller), 11b: pressure section (pressure roller), 11c: heat source (halogen heater), 20 (20A): cooling device (recording material cooling device), 21: first belt, 25: second belt, 26a (26b, 26c, 26d, 26e): tension roller (second belt tension roller), 30: cooling means (heat sink, heat sink), 90 (90A): cleaning means (belt cleaning device), 91...rubbing member (rubbing rotor, fur brush roller), 100 (1001)...image forming apparatus, 300...control section, 500...driving source (driving motor), 510...heating means (heater), 600a...reversal conveying section, 901...rubbing member (web member, web), 903...contact roller, 904...moving means (winding roller), PY (PM, PC, PK)...image forming section, S...recording material, T4...nip section (cooling nip)

Claims

1. The first belt, a second belt that contacts the first belt and forms a nip portion with the first belt; A plurality of tension rollers for tensioning the second belt; a cooling means for contacting an inner circumferential surface of the first belt to cool the first belt, thereby cooling a recording material passing through the nip portion; a first cleaning means for contacting an outer peripheral surface of the first belt and cleaning the outer peripheral surface of the first belt; a second cleaning means for contacting an outer circumferential surface of the second belt and cleaning the outer circumferential surface of the second belt; the second cleaning means has a rubbing member that rubs against the second belt, the rubbing member rubbing the second belt at a position facing a predetermined roller among the plurality of tension rollers via the second belt, A cooling device characterized by:

2. the second cleaning means contacts the outer circumferential surface of the second belt at any position from the downstream end of the nip portion to half the circumferential length of the second belt in a rotational direction of the second belt; 2. The cooling device according to claim 1 .

3. A heating means for heating the predetermined roller is provided.

2. The cooling device according to claim 1 .

4. The rubbing member is a fur brush.

2. The cooling device according to claim 1 .

5. The rubbing member is a rotatable rubbing rotor, and at least one of the first belt and the second belt is driven by a same driving source.

2. The cooling device according to claim 1 .

6. When the rubbing rotor and the second belt are viewed from the direction of the rotation axis of the rubbing rotor, the rotation directions of the rubbing rotor and the second belt are opposite to each other at a contact position between the rubbing rotor and the second belt.

6. The cooling device according to claim 5.

7. the rubbing member is a cloth-like web member that rubs against the second belt, The second cleaning means includes the web member, a contact roller that brings the web member into contact with the second belt, and a moving means that moves the web member so as to change a position where the web member contacts the second belt.

2. The cooling device according to claim 1 .

8. The moving means and at least one of the first belt and the second belt are driven by a same driving source.

8. The cooling device according to claim 7.

9. A heating means for heating the contact roller is provided.

9. The cooling device according to claim 7 or 8.

10. the cooling means is a heat sink that cools the first belt; 10. The cooling device according to claim 1 ,

Images