JP5636883B2 - Cooling device and image forming apparatus - Google Patents

Description

  The present invention relates to a cooling device that cools a sheet-like member and an image forming apparatus including the cooling device.

  In an image forming apparatus such as a copying machine, a printer, a facsimile, or a complex machine of these, a fixing device that melts toner on a sheet by heat and fixes an image is often used. The fixing temperature of this type of fixing device is generally controlled to be about 180 ° C. to 200 ° C., although it varies depending on the type of toner and paper, the paper conveyance speed, and the like. Further, the temperature of the sheet immediately after the fixing process is as high as about 100 ° C. to 130 ° C. For this reason, immediately after the fixing process, the toner on the sheet is still in a molten state, and then the sheet is discharged to the sheet discharge tray, whereby the toner is cooled and completely cured.

  However, when printing is continuously repeated and a large amount of sheets are stacked on the paper discharge tray, the sheets are not easily exposed to the outside air, so that heat radiation of the sheets is hindered and the toner is hard to be cured. Furthermore, coupled with the fact that pressure is generated on the sheets due to the weight of the stacked sheets, a phenomenon called so-called blocking occurs in which the sheets adhere to each other due to the adhesive force of the softened toner, and there is a problem that the image quality is significantly reduced. . In the worst case, the papers stuck with toner cannot be peeled off, and if they are forcibly peeled off, the toner will peel off or the paper will be torn.

  Conventionally, as a countermeasure against the toner curing failure, for example, a method of cooling a sheet on a conveyance belt by cooling an endless conveyance belt that carries and conveys a sheet by a cooling roller or a fan has been proposed. (See FIG. 6 of Patent Document 1 and Patent Document 2).

  However, in the above conventional cooling method, one side of the paper that contacts the conveyor belt is effectively cooled, but heat still remains from the inside of the paper to the back side. The remaining heat diffuses to the front side, so that the temperature on the front side rises again. Furthermore, the thicker the paper, the more difficult it is to cool the back side from inside the paper. For this reason, with the conventional cooling method, the cooling effect especially with respect to cardboard or the like was insufficient.

  In addition, in the conventional configuration, in order to obtain a sufficient cooling effect, it is necessary to lengthen the conveyor belt to increase the contact time between the conveyor belt and the paper, or to greatly improve the cooling performance of the cooling device. Therefore, there arises a problem that the apparatus becomes large.

  In view of such circumstances, an object of the present invention is to provide a cooling device capable of improving a cooling effect while suppressing an increase in size of the device, and an image forming apparatus including the cooling device.

The present invention relates to a belt conveying means for conveying the recording medium by a front side belt that contacts the front side of the recording medium and a back side belt that contacts the back side of the recording medium, and a surface of the front side belt that contacts the recording medium. A first cooling member that contacts the opposite surface and cools the recording medium from the front side via the front belt, and a position in the transport direction for transporting the recording medium with respect to the first cooling member. A second cooling member that is disposed in a shifted manner and that contacts a surface of the backside belt opposite to the surface that contacts the recording medium, and cools the recording medium from the backside via the backside belt; The recording medium that has passed through a fixing device that heats and fixes an unfixed image formed on the recording medium is heated between the first cooling member and the second cooling member. Na , The front and back of the heat of the recording medium, in which deprive said first cooling member by the second cooling member.

Thus, it is possible to cool the recording medium from its both sides (front side and back side), as compared with the case of cooling only one side of the recording medium, it is possible to lower the temperature of the recording medium effectively . In addition, this makes it possible to reduce the cooling time, and thus the size of the apparatus can be reduced.

According to the present invention, since the recording medium can be cooled from both sides thereof, even a thick recording medium can be effectively cooled. Further, according to the present invention, the cooling performance can be improved, so that the cooling time can be shortened and the apparatus can be downsized.

1 is a schematic diagram illustrating an overall configuration of an image forming apparatus according to the present invention. It is the schematic which showed the structure of the cooling device which concerns on 1st Embodiment of this invention. It is an enlarged view of a conveyance belt. It is the schematic which showed the structure of the coolant circulation path which connected a pair of cooling member in parallel. It is the schematic which showed the structure of the cooling fluid circulation path which connected a pair of cooling member in series. It is the graph showing the temperature change of the recording medium at the time of each cooling in this invention and a comparative example. It is the schematic which showed the structure of the cooling device which concerns on 2nd Embodiment of this invention. It is the schematic which showed the structure of the cooling device which concerns on 3rd Embodiment of this invention. It is a graph showing the temperature change of the recording medium at the time of cooling in 3rd Embodiment of this invention. It is the schematic which showed the structure of the cooling device which concerns on 4th Embodiment of this invention. It is the schematic which showed the structure of another embodiment of the said coolant circulation path | route.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

FIG. 1 is a schematic configuration diagram of a color image forming apparatus according to the present invention.
The image forming apparatus shown in FIG. 1 includes a tandem type image forming unit in which four process units 1Y, 1C, 1M, and 1Bk as image forming units are arranged side by side. Each of the process units 1Y, 1C, 1M, and 1Bk is configured to be detachable from the image forming apparatus main body 100, and yellow (Y), cyan (C), magenta (M), and magenta (M) corresponding to the color separation components of the color image. The configuration is the same except that toners of different colors of black (Bk) are accommodated.

  Specifically, each of the process units 1Y, 1C, 1M, and 1Bk includes a drum-shaped photosensitive member 2 as a latent image carrier, a charging roller 3 as a charging unit that charges the surface of the photosensitive member 2, and a photosensitive member. 2 is provided with a developing device 4 as a developing means for forming a toner image on the surface of 2 and a cleaning blade 5 as a cleaning means for cleaning the surface of the photoreceptor 2. In FIG. 1, only the photoconductor 2, the charging roller 3, the developing device 4, and the cleaning blade 5 included in the yellow process unit 1 </ b> Y are denoted by reference numerals. Omitted.

  In FIG. 1, an exposure device 6 as an exposure means for exposing the surface of the photoreceptor 2 is disposed above each process unit 1Y, 1C, 1M, 1Bk. The exposure device 6 includes a light source, a polygon mirror, an f-θ lens, a reflection mirror, and the like, and irradiates the surface of each photoconductor 2 with laser light based on image data.

  A transfer device 7 is disposed below each process unit 1Y, 1C, 1M, 1Bk. The transfer device 7 has an intermediate transfer belt 10 constituted by an endless belt as a transfer body. The intermediate transfer belt 10 is stretched around a plurality of rollers 21 to 24 as support members, and when one of the rollers 21 to 24 rotates as a driving roller, the intermediate transfer belt 10 is changed to an arrow in the figure. It is configured to run around (rotate) in the direction shown.

  Four primary transfer rollers 11 as primary transfer means are disposed at positions facing the four photoconductors 2. Each primary transfer roller 11 presses the inner peripheral surface of the intermediate transfer belt 10 at each position, and a primary transfer nip is formed at a location where the pressed portion of the intermediate transfer belt 10 and each photoconductor 2 are in contact with each other. ing. Each primary transfer roller 11 is connected to a power source (not shown), and a predetermined direct current voltage (DC) and / or alternating current voltage (AC) is applied to the primary transfer roller 11.

  A secondary transfer roller 12 as a secondary transfer unit is disposed at a position facing one roller 24 that stretches the intermediate transfer belt 10. The secondary transfer roller 12 presses the outer peripheral surface of the intermediate transfer belt 10, and a secondary transfer nip is formed at a location where the secondary transfer roller 12 and the intermediate transfer belt 10 are in contact with each other. Similar to the primary transfer roller 11, the secondary transfer roller 12 is connected to a power source (not shown) so that a predetermined direct current voltage (DC) and / or alternating current voltage (AC) is applied to the secondary transfer roller 12. It has become.

  A plurality of paper feed cassettes 13 that contain sheet-like recording media P such as paper and OHP are disposed below the image forming apparatus main body 100. Each paper feed cassette 13 is provided with a paper feed roller 14 for feeding out the stored recording medium P. A paper discharge tray 20 for stocking the recording medium P discharged outside the apparatus is provided on the left outer surface of the image forming apparatus main body 100 in the drawing.

  In the image forming apparatus main body 100, a transport path R for transporting the recording medium P from the paper feed cassette 13 through the secondary transfer nip to the paper discharge tray 20 is disposed. In the conveyance path R, a registration roller 15 is disposed upstream of the position of the secondary transfer roller 12 in the recording medium conveyance direction. Further, a fixing device 8, a cooling device 9, and a pair of discharge rollers 16 are sequentially disposed downstream of the position of the secondary transfer roller 12 in the recording medium conveyance direction. The fixing device 8 includes, for example, a fixing roller 17 as a fixing member having a heater (not shown) therein, and a pressure roller 18 as a pressure member that presses the fixing roller 17. A fixing nip is formed at a position where the fixing roller 17 and the pressure roller 18 are in contact with each other.

The basic operation of the image forming apparatus will be described below with reference to FIG.
When the image forming operation is started, the photoreceptors 2 of the process units 1Y, 1C, 1M, and 1Bk are rotated counterclockwise in the drawing, and the surface of each photoreceptor 2 is made to have a predetermined polarity by the charging roller 3. It is charged like this. Based on image information of a document read by a reading device (not shown), the surface of each photoconductor 2 charged from the exposure device 6 is irradiated with laser light, and an electrostatic latent image is formed on the surface of each photoconductor 2. Is done. At this time, the image information to be exposed on each photoconductor 2 is monochromatic image information obtained by separating a desired full-color image into color information of yellow, cyan, magenta, and black. As the electrostatic latent image formed on the photosensitive member 2 is supplied with toner by each developing device 4, the electrostatic latent image is visualized (visualized) as a toner image.

  One of the rollers that stretches the intermediate transfer belt 10 is driven to rotate, and the intermediate transfer belt 10 runs around in the direction of the arrow in the figure. Also, a primary transfer nip between each primary transfer roller 11 and each photoreceptor 2 is applied to each primary transfer roller 11 by applying a constant voltage or a voltage controlled by a constant current opposite to the charging polarity of the toner. A transfer electric field is formed. Then, the toner images of the respective colors formed on the respective photoconductors 2 are sequentially superimposed and transferred onto the intermediate transfer belt 10 by the transfer electric field formed in the primary transfer nip. Thus, the intermediate transfer belt 10 carries a full-color toner image on its surface. Further, the toner on each photoreceptor 2 that could not be transferred to the intermediate transfer belt 10 is removed by the cleaning blade 5.

  The recording medium P is carried out of the paper feed cassette 13 by the rotation of the paper feed roller 14. The unloaded recording medium P is timed by the registration roller 15 and sent to the secondary transfer nip between the secondary transfer roller 12 and the intermediate transfer belt 10. At this time, a transfer voltage having a polarity opposite to the toner charging polarity of the toner image on the intermediate transfer belt 10 is applied to the secondary transfer roller 12, thereby forming a transfer electric field in the secondary transfer nip. Then, the toner images on the intermediate transfer belt 10 are collectively transferred onto the recording medium P by the transfer electric field formed in the secondary transfer nip. Thereafter, the recording medium P is sent to the fixing device 8, and the recording medium P is pressurized and heated by the fixing roller 17 and the pressure roller 18, and the toner image is fixed on the recording medium P. The recording medium P is cooled by the cooling device 9 and then discharged to the paper discharge tray 20 by the pair of discharge rollers 16.

  The above description is an image forming operation when a full-color image is formed on a recording medium. A single-color image is formed using any one of the four process units 1Y, 1C, 1M, and 1Bk, and 2 Two or three process units can be used to form a two or three color image.

Next, the configuration of the cooling device mounted on the image forming apparatus of the present invention will be described.
FIG. 2 is a schematic diagram showing the configuration of the cooling device according to the first embodiment of the present invention.
As shown in FIG. 2, the cooling device 9 includes a pair of conveying belts 30 </ b> A and 30 </ b> B that are arranged to face each other in the vertical direction. Each of the conveyor belts 30 </ b> A and 30 </ b> B is composed of an endless belt member and is stretched by a pair of support rollers 31. One of the pair of support rollers 31 is configured to be rotationally driven by a drive source (not shown), and the support roller 31 rotates the transport belts 30A and 30B by the rotation to transport the recording medium P. Functions as a transporting means. Specifically, the rotation of the support roller 31 in the direction shown by the arrow in the drawing causes the conveyor belts 30A and 30B to rotate so that the opposing belt surfaces move in the same direction and in the same direction. The recording medium P sandwiched between the conveyor belts 30A and 30B is conveyed from the right side to the left side in the drawing.

  As shown in FIG. 2, cooling members 32A and 32B are disposed inside the pair of transport belts 30A and 30B, respectively. Each of the cooling members 32A and 32B is disposed so as to face each other via the conveying belts 30A and 30B, and is opposite to the surface (outer peripheral surface) that contacts the recording medium P of the conveying belts 30A and 30B, respectively. It is in contact with the surface (inner peripheral surface). In addition, a spring member 33 is attached to each of the cooling members 32A and 32B as a pressurizing unit that pressurizes the cooling members 32A and 32B in a direction in contact with the conveying belts 30A and 30B. The cooling members 32A and 32B may be simply brought into contact with each of the conveyor belts 30A and 30B without being brought into pressure contact therewith.

FIG. 3 is an enlarged view of the conveyor belt.
As shown in FIG. 3, each of the conveyor belts 30 </ b> A and 30 </ b> B includes an inner peripheral base layer 301 and an outer peripheral elastic layer 302. For example, polyimide can be used as the material of the base layer 301, and silicon rubber can be used as the material of the elastic layer 302. Further, a filler having good heat conductivity may be added to the base layer 301 and the elastic layer 302. As the base layer 301, a metal material such as stainless steel can be used instead of polyimide.

FIG. 4 is a schematic view showing the configuration of the coolant circulation path provided in the cooling device.
As shown in FIG. 4, the cooling device 9 includes a heat radiating portion 34 that radiates heat of the coolant, a pump 35 that circulates the coolant, a tank 36 that stores the coolant, and the pair of cooling members 32A and 32B. And a pipe 37 as a circulation path for circulating the coolant by connecting the heat radiating section 34, the pump 35 and the tank 36. Each of the pair of cooling members 32A and 32B has a coolant flow path 320 through which the coolant passes. Each coolant flow path 320 is connected to the pipe 37 via the joint 38, and the cooling members 32 </ b> A and 32 </ b> B are configured to be able to contact and separate from the pipe 37. For this reason, only the cooling members 32A and 32B can be easily separated during maintenance or the like. The joint 38 preferably has a valve for preventing liquid leakage. The heat radiating section 34 is provided with a radiator 39 connected to a pipe 37 and a fan 40 that blows air toward the radiator 39. In the example shown in FIG. 4, the pair of cooling members 32A and 32B are connected in parallel to each other by the pipe 37, but the cooling members 32A and 32B may be connected in series as in the example shown in FIG.

Hereinafter, the operation and effect of the cooling device according to the first embodiment of the present invention will be described.
In FIG. 2, when the recording medium P enters between the pair of conveying belts 30A and 30B, the recording medium P is conveyed downstream (left side in the figure) by the rotating conveying belts 30A and 30B. At this time, the recording medium P comes into contact with the mutually opposing belt surfaces of the conveying belts 30A and 30B, so that the cooling members 32A and 32B are moved from the front side and the back side of the recording medium P via the conveying belts 30A and 30B. Heat is taken away and cooled.

  In FIG. 4, the coolant stored in the tank 36 is sent by the pump 35 in the direction of the arrow in the figure. The cooling liquid absorbs heat taken from the recording medium P by the cooling members 32A and 32B when passing through the cooling members 32A and 32B. Thereafter, the coolant is cooled when passing through the heat radiating portion 34 and returns to the tank 36. In this manner, the recording medium P is cooled from both sides via the conveying belts 30A and 30B by circulating the cooling liquid between the cooling members 32A and 32B and the heat radiating portion 34 and repeatedly performing the heat absorption and heat radiation cycle. .

FIG. 6 is a graph showing the temperature change of the recording medium during cooling in the present invention and the comparative example. In the figure, (a) shows a comparative example, and (b) shows the present invention.
The cooling device of the present invention is the same as the configuration of the first embodiment shown in FIG. 2, and the cooling device of the comparative example is the cooling device 9 shown in FIG. 2, among the pair of cooling members 32 </ b> A and 32 </ b> B. Only one side is provided. Moreover, the temperature detection of the recording medium was performed separately on the front surface and the back surface.

First, in the case of the comparative example, the recording medium is cooled by a cooling member provided on one side. For this reason, as shown in FIG. 6A, the temperature of the surface on the side where the cooling member is provided is lowered, but since heat remains from the inside of the recording medium to the back surface, the cooling process is completed. The surface temperature rises due to the diffusion of heat on the back side from the inside. If left as it is in an adiabatic state, the temperature of the recording medium converges to a uniform temperature T _L [° C.] from the front surface to the back surface.

On the other hand, in the case of the present invention, since the recording medium is cooled from both sides by the pair of cooling members, both the temperatures on the front surface and the back surface can be effectively reduced as shown in FIG. As a result, in the above comparative example, the cooling time required to reduce the temperature of the recording medium from T _H [° C.] to T _L [° C.] is t [s], whereas in the present invention, It becomes about 0.35 t [s] which reduced 60% or more of the cooling time in the comparative example, and the cooling time can be greatly shortened. The cooling time of the recording medium is proportional to the length of the cooling member in the recording medium conveyance direction when the recording medium conveyance speed is constant (cooling time = length of the cooling member in the recording medium conveyance direction / conveying speed). ) By shortening the cooling time, the length of the cooling member in the recording medium conveyance direction can be shortened, and the apparatus can be miniaturized.

  In this embodiment, the cooling members 32A and 32B are brought into pressure contact with the conveying belts 30A and 30B, so that the cooling members 32A and 32B contact the conveying belts 30A and 30B, and the conveying belts 30A and 30B and the recording medium. Sufficient contact with P can be ensured, and the cooling effect is improved.

FIG. 7 is a schematic view showing the configuration of the cooling device according to the second embodiment of the present invention.
As shown in FIG. 7, the cooling device 9 according to the second embodiment has four transport belts 30A, 30B, 30C, and 30D, and each of these two faces each other to form a transport belt pair. Yes. The two pairs of transport belts are arranged side by side in the recording medium transport direction. Each of the conveyor belts 30A, 30B, 30C, and 30D is stretched by a pair of support rollers 31 as in the first embodiment, and one of the pair of support rollers 31 is rotated by a drive source (not shown). By driving, the opposite belt surfaces rotate at the same speed and in the same direction. In the example shown in FIG. 7, the recording medium P is conveyed from the right side to the left side in the drawing as each of the conveyance belts 30A, 30B, 30C, and 30D rotates.

  Further, in each of the conveyor belt pairs, a cooling member 32A (or 32B) is disposed inside one of the paired conveyor belts, and the disposed position is upstream of the recording medium conveyance direction (in the drawing). The conveyance belt pair on the right side and the conveyance belt pair on the downstream side (left side in the figure) are upside down. Specifically, in the left conveying belt pair 30A, 30B in FIG. 7, a cooling member 32B is disposed inside the lower conveying belt 30B. In the right conveying belt pair 30C, 30D in FIG. The cooling member 32A is disposed inside the upper conveyor belt 30C. Further, the cooling members 32A and 32B are in contact with the surfaces of the conveyor belts 30B and 30C opposite to the surfaces that are in contact with the recording medium P, respectively.

  A plurality of pressure rollers 41 urged by a spring member 42 as pressure means are provided inside the other conveyance belts 30A and 30D facing the respective conveyance belts 30B and 30C provided with the cooling members 32A and 32B. It is arranged. Each of the pressure rollers 41 presses the inner peripheral surface of the portion of the conveying belts 30A and 30D that contacts the recording medium P toward the cooling member 32A (or 32B), so that the conveying belt pair is in pressure contact with each other. .

  In FIG. 7, there is a gap between the opposite belt surfaces of the right conveyance belt pair 30 </ b> C and 30 </ b> D, but correctly, the opposite belt surfaces are pressed against each other by the pressure of the pressure roller 41. . Moreover, in each conveyance belt pair, it is good also as a structure which does not press each other but the belt surface which opposes only. Further, in each conveyance belt pair, the arrangement positions of the pressure roller 41 and the cooling members 32A and 32B may be reversed upside down. Further, among the conveyor belts facing each other, a conveyor belt not provided with a cooling member can be a rotating body such as a roller other than the belt, or a non-rotating guide member.

  The characteristic portions of the configuration according to the second embodiment of the present invention have been described above. However, the other configurations are the same as those of the first embodiment, and thus the description thereof is omitted here.

Hereinafter, the operation and effect of the cooling device according to the second embodiment of the present invention will be described.
In FIG. 7, the recording medium P is conveyed downstream (left side in the figure) by the pair of conveyance belts 30C and 30D on the right side in the figure and then the pair of conveyance belts 30A and 30B on the left side in the figure. First, when the recording medium P enters between the pair of conveyance belts 30C and 30D on the right side of the drawing, heat is taken from the front side (upper surface) of the recording medium P by the cooling member 32A disposed in the upper conveyance belt 30C. To be cooled. Next, when the recording medium P enters between the pair of conveyance belts 30A and 30B on the left side of the drawing, heat is applied from the back surface (lower surface) of the recording medium P by the cooling member 32B disposed in the lower conveyance belt 30B. Deprived and cooled.

  As described above, also in the second embodiment of the present invention, the recording medium can be cooled from both sides by the two cooling members 32A and 32B, so that the temperature of the recording medium can be effectively reduced. In addition, since the cooling time can be shortened, the apparatus can be downsized. In this case, the pressure roller 41 sufficiently ensures the contact between the cooling member and the conveyance belt and the contact between the conveyance belt and the recording medium, so that the cooling effect is improved.

  Also, in the second embodiment, unlike the first embodiment shown in FIG. 2, the two cooling members 32A and 32B are not disposed so as to face each other, and the cooling members 32A and 32B are provided as separate conveying belts. One pair is arranged, and the positions are shifted from each other (in the recording medium conveyance direction). Therefore, in the second embodiment, the resistance in the belt rotation direction (traveling direction) due to the cooling members 32A and 32B coming into contact with the conveyance belts 30C and 30B can be reduced as compared with the configuration of the first embodiment. The driving force required to rotate the conveyor belt can be reduced. Accordingly, the configuration of the second embodiment has a small driving force of the conveyor belt, and it is difficult to adopt the configuration of the first embodiment (the conveyor belt while ensuring the contact surface pressure between the cooling member and the conveyor belt). It is preferable to employ this method when it is difficult to rotate the motor). On the other hand, the configuration of the first embodiment can cool the recording medium more effectively because the front and back of the recording medium can be cooled almost simultaneously as long as the driving force of the conveying belt can be secured.

FIG. 8 is a schematic view showing the configuration of the cooling device according to the third embodiment of the present invention.
As shown in FIG. 8, the cooling device 9 according to the third embodiment of the present invention includes a pair of conveying belts 30A and 30B that are longer in the recording medium conveying direction than the configuration of the first embodiment shown in FIG. . Cooling members 32A and 32B and a plurality of pressure rollers 41 are disposed inside the conveyor belts 30A and 30B, respectively. Specifically, in the upper conveyance belt 30A, the cooling member 32A is disposed on the upstream side (right side in the figure) in the recording medium conveyance direction, and the pressure roller 41 is located on the downstream side (left side in the figure) in the recording medium conveyance direction. It is arranged. On the other hand, in the lower conveyance belt 30B, on the contrary to the upper conveyance belt 30A, a cooling member 32B is disposed on the downstream side (left side in the drawing) in the recording medium conveyance direction, and the pressure roller 41 conveys the recording medium. It is arranged upstream in the direction (right side in the figure). In other words, the cooling members 32A and 32B and the pressure roller 41 are disposed to face each other with the conveying belts 30A and 30B interposed therebetween. Note that the arrangement positions of the pressure roller 41 and the cooling members 32A and 32B arranged on the upper conveyance belt 30A and the lower conveyance belt 30B may be reversed upside down. In this embodiment, the opposing belt surfaces may be simply brought into contact with each other without being brought into pressure contact with each other.

  The characteristic portions of the configuration according to the third embodiment of the present invention have been described above. However, the other configurations are the same as those of the first embodiment, and thus the description thereof is omitted here.

Hereinafter, the operation and effect of the cooling device according to the third embodiment of the present invention will be described.
In FIG. 8, when the recording medium P is conveyed downstream (left side in the figure) by the rotating conveying belts 30A and 30B, first, the recording medium P passes through the position of the cooling member 32A disposed on the upper side. At this time, heat is removed from the front side (upper surface) of the recording medium P and cooled by the cooling member 32A disposed on the upper side. Next, the recording medium P is transported to the position of the cooling member 32B disposed on the lower side, and the recording medium P is cooled by removing heat from the back surface (lower surface) by the cooling member 32B disposed on the lower side. Is done.

FIG. 9 is a graph showing the temperature change of the recording medium during cooling in the third embodiment of the present invention.
Also in this case, the temperature detection of the recording medium was performed separately on the front surface and the back surface.
As described above, in the configuration of the third embodiment, since the recording medium is first cooled from the surface side, the surface temperature particularly decreases at first as shown in FIG. Next, when the recording medium is cooled from the back surface side, the temperature of the back surface decreases, and the surface temperature and the back surface temperature are reversed. Thereafter, when left in an adiabatic state, the temperatures of the front and back surfaces converge to a uniform temperature T _L [° C.]. In this case, the cooling time required to lower the temperature of the recording medium from T _H [° C.] to T _L [° C.] is about 30% of the cooling time in the comparative example shown in FIG. It becomes 0.7 t [s], and the cooling time can be shortened.

  As described above, also in the third embodiment of the present invention, since the recording medium can be cooled from both sides, the temperature of the recording medium can be effectively reduced as compared with the case where only one side of the recording medium is cooled. Can do. In addition, this makes it possible to reduce the cooling time, and thus the size of the apparatus can be reduced.

  Further, in the configuration of the third embodiment of the present invention, since the two cooling members 32A and 32B are arranged so as to be shifted from each other in the recording medium conveyance direction, similarly to the second embodiment shown in FIG. Resistance in the belt rotation direction (traveling direction) due to the cooling members 32A and 32B coming into contact with the conveying belts 30A and 30B can be reduced, and the driving force required to rotate the conveying belt can be reduced. Furthermore, since the configuration of the third embodiment can reduce the number of conveyor belts installed compared to the configuration shown in FIG. 7, the apparatus can be downsized. Specifically, the configuration shown in FIG. 8 can be shortened in the recording medium conveyance direction by about the diameter of the two support rollers 31 compared to the configuration shown in FIG.

FIG. 10 is a schematic view showing the configuration of the cooling device according to the fourth embodiment of the present invention.
As shown in FIG. 10, the cooling device 9 according to the fourth embodiment of the present invention includes a plurality of fans 43 in each of the conveyor belts 30A and 30B in addition to the configuration shown in FIG. The plurality of fans 43 are arranged so as to blow air from between the pressure rollers 41 toward the surface opposite to the surface that contacts the recording medium P of the transport belts 30A and 30B. In this case, since the plurality of fans 43 function as auxiliary cooling means for cooling the conveying belts 30A and 30B by the air blowing and assisting the cooling effect of the recording medium P, the cooling effect is improved. Further, since the pressure of the opposite belt surfaces can be assisted by the wind pressure of the fan 43, the contact between the transport belts 30A and 30B and the recording medium P, and the contact between the transport belts 30A and 30B and the cooling members 32A and 32B. Can be ensured more reliably, and the cooling effect can be further improved. In addition, the cooling device according to the fourth embodiment can achieve the same operations and effects as the cooling device according to the third embodiment shown in FIG. 9, but this is as described above. Is omitted.

FIG. 11 is a schematic diagram showing the configuration of still another embodiment of the coolant circulation path in the present invention.
As shown in FIG. 11, in this embodiment, a heat pump heat exchanger 44 is provided in the heat radiating section 34. The other configuration is the same as the configuration shown in FIG. The heat pump heat exchanger 44 includes an evaporator 45, a compressor 46, a condenser 47, and an expansion valve 48. A refrigerant circulates in the heat pump heat exchanger 44, and the evaporator 45 absorbs heat from the coolant, and the refrigerant changed from liquid to gas becomes high-temperature and high-pressure gas by the compressor 46 and is cooled by the condenser 47. After becoming condensate, the pressure is reduced and reduced by the expansion valve 48. By using such a heat pump heat exchanger, it becomes possible to cool the coolant in the coolant circulation path to below the ambient temperature, and the cooling performance of the recording medium by the cooling member is greatly improved.

  As described above, the cooling device according to the present invention includes the first belt member that contacts one surface of the recording medium and the second belt member that contacts the other surface of the recording medium. Since the first cooling member and the second cooling member that are in contact with the surface opposite to the surface in contact with each recording medium are provided, the recording medium can be cooled from both sides by each cooling member. . As a result, even a thick recording medium can be effectively cooled, and occurrence of problems such as blocking can be prevented. Further, according to the present invention, the cooling performance can be improved, so that the cooling time can be shortened and the apparatus can be downsized.

  In addition, this invention is not limited to the above-mentioned embodiment, Of course, a various change can be added in the range which does not deviate from the summary of this invention. In the above-described embodiment, the case where the configuration of the present invention is applied to a cooling device that cools a recording medium has been described as an example. However, the configuration of the present invention can also be applied to a cooling device that cools sheet-like members other than paper. is there. The image forming apparatus equipped with the cooling device of the present invention is not limited to that shown in FIG. Other copiers, printers, facsimiles, or complex machines of these can be mounted with the cooling device of the present invention.

9 Cooling device 30A Conveyor belt (belt member)
30B Conveyor belt (belt member)
30C Conveyor belt (belt member)
30D Conveyor belt (belt member)
32A Cooling member 32B Cooling member 33 Spring member (pressurizing means)
34 Radiating section 35 Pump 37 Piping (circulation path)
41 Pressure roller (Pressure means)
42 Spring member (pressurizing means)
43 Fan (auxiliary cooling means)
44 Heat pump heat exchanger 320 Coolant flow path P Recording medium (sheet-like member)

Japanese Patent No. 4109886 JP 2009-175260 A

Claims (10)

Belt conveying means for conveying the recording medium by a front side belt that contacts the front side of the recording medium and a back side belt that contacts the back side of the recording medium;
A first cooling member that contacts a surface of the front belt opposite to the surface that contacts the recording medium, and cools the recording medium from the front side via the front belt;
The first cooling member is disposed with a position shifted in the transport direction for transporting the recording medium, and is in contact with a surface of the back belt opposite to the surface in contact with the recording medium, A second cooling member for cooling the recording medium from the back side via the back side belt;
Equipped with a,
The recording medium that has passed through a fixing device that heats and fixes an unfixed image formed on the recording medium is heated without being heated between the first cooling member and the second cooling member. A cooling device , wherein heat on both sides of the medium is taken away by the first cooling member and the second cooling member . Belt conveying means for conveying the recording medium by a front side belt that contacts the front side of the recording medium and a back side belt that contacts the back side of the recording medium;
A first cooling member that contacts a surface of the front belt opposite to the surface that contacts the recording medium, and cools the recording medium from the front side via the front belt;
The first cooling member is disposed with a position shifted in the transport direction for transporting the recording medium, and is in contact with a surface of the back belt opposite to the surface in contact with the recording medium, A second cooling member for cooling the recording medium from the back side via the back side belt;
With
After the final heating of the recording medium is performed, the recording medium is cooled from the front side and the back side by the first cooling member and the second cooling member.
A cooling device characterized by . The front belt has a first belt member and a third belt member;
The back belt has a fourth belt member facing the first belt member and a second belt member facing the third belt member;
Disposing the first cooling member on the first belt member;
The cooling device according to the second cooling member to claim 1 or 2 is disposed on the second belt member. Wherein the first cooling member, the cooling device according to any one of claims 1-3 which is disposed upstream of the conveying direction for conveying the recording medium than the second cooling member. Wherein the first cooling member, the cooling device according to any one of claims 1-3 which is disposed on the downstream side in the transport direction for transporting the recording medium than the second cooling member. A roller for bringing the front belt and the back belt into contact or pressure contact with each other;
The roller according to any one of claims 1 to 5, which is disposed respectively opposite the said second cooling member and the first cooling member through said back side belt and the front side belt Cooling system. The first cooling member and the second cooling member have a coolant flow path through which a coolant passes,
A heat dissipating part for dissipating the heat of the coolant;
A pump for circulating the coolant;
The cooling device according to any one of claims 1 to 6, further comprising a circulation path that connects the first cooling member, the second cooling member, the heat radiating unit, and the pump to circulate the cooling liquid. . The first cooling member and the second cooling member are connected in series, and of the first cooling member and the second cooling member, the cooling on the upstream side from the cooling member on the downstream side in the recording medium conveyance direction. The cooling device according to claim 7 , wherein a coolant flows through the member . An image forming apparatus comprising the cooling device according to claim 1. A fixing device that heats and fixes an unfixed image formed on a recording medium by a fixing roller and a pressure roller; and
A cooling device according to claim 4 or 5,
Disposing the first cooling member on the fixing roller side;
An image forming apparatus, wherein the second cooling member is disposed on the pressure roller side .

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