JP4445336B2 - Cooling device, image forming apparatus - Google Patents

Description

  The present invention relates to a cooling device for a sheet-like medium that has passed through a thermal fixing device, an image forming apparatus such as a copying machine, a printer, and a plain paper facsimile equipped with the cooling device, and particularly to a high-speed image forming apparatus.

  High-speed copiers, printers, and the like that fuse a toner to a sheet-like medium, for example, a sheet by a heat fixing device, have been widely used. In general, the temperature at the time of heat fixing is about 170 ° C., although it varies depending on the type of toner, and the paper surface temperature after fixing is also about 150 ° C., which is high. At this temperature, the melted toner is completely cooled and cannot be solidified, and has adhesiveness.

  In this state, when a large number of copies are continuously repeated and the sheets are stuck, a phenomenon in which the toner on the sheet sticks to the back side of another sheet (blocking phenomenon) occurs and the image quality and the like are impaired. Furthermore, in order to prevent wasteful use of paper due to recent demands for resource saving, double-sided copying has been frequently used. In addition to the above problems, it is necessary to consider paper cooling during double-sided copying.

  In a high-speed processing machine, for example, a high-speed copying machine having a copy speed of 100 sheets per minute (100 cpm: Copy Per Minutes) or more, in the fixing process in which the toner on the paper is melted and fused by heat, The toner on the paper is sufficiently cooled when the temperature of the paper rises to about 150 ° C and the paper is overlapped or copied again on the back side, such as when copying is repeated one after another or when copying on both sides. Therefore, there is a problem that a blocking phenomenon may occur in which the sheets stick to each other due to viscosity, or the sheet curls due to heat and a jam or the like occurs.

  (A) Therefore, it is necessary to cool the sheet immediately after fixing the toner. As a cooling means, a paper cooling method using a heat pipe excellent in thermal conductivity has been proposed, and a paper is cooled using a pair of upper and lower heat pipes (see, for example, Patent Document 1).

  In this disclosed technique, heat of a sheet is absorbed by a heat pipe, transported, and cooled by a heat dissipating fin provided at the end of the heat pipe. In this method, it is important to efficiently cool the heat dissipating fins, and the fan is forcibly cooled by a fan. For this reason, a large sirocco fan is required, and side effects such as increased noise will occur.

  (B) Some devices have been devised to improve the heat radiation efficiency by reducing the thickness of the hollow material that is the heat pipe heat radiating portion, and the air intake and exhaust of the cooling fan (for example, Patent Document 2) reference). However, this technique cannot provide sufficient performance for cooling the paper. This heat pipe method is a cooling means that also serves as a paper transport. However, with a high-speed machine with a copy speed exceeding 100 cpm, the paper transport speed is 500 mm / s, and the rotation speed of a 30φ diameter heat pipe also exceeds 300 rpm. become. Then, the evaporation of the liquid in the heat pipe and the liquid transport due to the capillary phenomenon decrease, resulting in a problem that the thermal resistance becomes very large and cannot be applied essentially.

  (C) As a technique for forcibly air-cooling recording paper using a fan, a method for preventing the curling by blowing air is disclosed (for example, see Patent Document 3). However, this disclosed technique requires a special device such as a means for stably holding paper and a duct.

JP-A-10-207155 JP-A-11-007218 JP 2000-75709 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet cooling device for sheet-like medium with high efficiency that can replace the conventional technique.

In order to achieve the object, the present invention is configured as follows.
(1) In a cooling device for cooling a sheet-like medium on which toner is fixed by a heat fixing device,
A transport roller for transporting the sheet-like medium;
A conveyance belt that conveys the sheet-like medium by pressing the sheet-like medium to the conveyance roller;
A plurality of belt driving rollers for driving the conveyor belt,
At least one of the plurality of belt drive rollers and the transport roller,
With a tubular structure through which liquid fluid flows inside the roller,
The liquid fluid flows from one end of the tubular structure roller,
The liquid fluid flows out from the opposite end ,
By the conveyance belt cooled by the drive roller and the conveyance roller,
Comprising a configuration for cooling the sheet-like medium from both sides;
The conveyance roller is pressed toward the conveyance belt to form a nip portion in a surface state , and the sheet-like medium is conveyed and cooled at the nip portion in the surface state. 1).
(2) In the cooling device according to (1), when the fluid is a liquid, the cooling device can be provided with a temperature control device capable of controlling the liquid temperature from a room temperature to a rising temperature within 10 ° C. (claim) Item 2). Here, the temperature control device may be a cooling device provided with a tank for pooling liquid and a natural air-cooling cooling means attached with heat radiation fins (Claim 3). Further, the temperature control device may be a cooling device including a tank for pooling liquid, a radiating fin, and a forced air cooling cooling means attached to an air cooling fan. Furthermore, the temperature control device may be a cooling device including a tank for pooling liquid and an electronic cooling means. The temperature control device may be a cooling device including a compressor, an evaporator, and a condenser (Claim 6).
(3) A structure in which a partition plate is provided spirally in the longitudinal direction of the roller so that the inner wall of either or both of the transport roller and the belt driving roller is spirally moved along with the rotation of the roller. (Claim 7).
(4) With regard to the tubular structure of the roller described above, the pipe has a double pipe structure, and a cooling device configured to flow a fluid to the outside and the inside of the double pipe can be provided.
(5) In an image forming apparatus having a heat fixing device for fixing an unfixed image on a sheet-like medium by at least heat, the cooling device for cooling the sheet-like medium fixed with toner by the heat fixing device is the above-described cooling device. The image forming apparatus can be an image forming apparatus described in one of the above (claim 9).

In the present invention, the cooling device of high efficiency alternative to the prior art, it is possible to provide an image forming apparatus equipped with the cooling device.

  Embodiments of the present invention will be described below.

[1] First Embodiment In the cooling apparatus of this example, high-temperature paper is efficiently cooled for a high-speed copying machine, a printer, or the like capable of copying at 100 cpm or more. In this example, various problems caused by the sheet temperature remaining high even after the sheet has passed through the heat fixing device, which is a process of fusing toner by heat, are solved.

  In this example, a transport roller provided for transporting paper is used as a cooling means, and the roller is improved to a hollow tube so that a fluid flows in and cools. The roller cooled by the fluid by the fluid removes heat from the sheet while conveying the high-temperature sheet discharged from the heat fixing device.

  FIG. 1 shows a layout of the fixing roller 1, the pressure roller 2, and the cooling device 88 that constitute the thermal fixing device 3. FIG. 2 shows an outline of the transport roller 8. In FIG. 1, the main part of the heat fixing device 3 is composed of a fixing roller 1 and a pressure roller 2.

  The fixing roller 1 includes a halogen lamp heater (not shown) inside, and the outer skin is processed into a roller shape with silicon rubber. Located on the lower side is a pressure roller 2, and the pressure roller 2 presses the passing paper against the fixing roller 1 with an appropriate pressure.

  At this point, the developed toner adheres on the paper, but after passing between the two rollers (the pressure roller 2 and the fixing roller 1), it is fused on the paper. The sheet discharged from the heat fixing device 3 is sent along the guide plate 4 to the conveying belt portion of the cooling device 88.

The conveyor belt section two drive rollers over which are arranged at intervals in the conveying direction of the sheet is provided. The right drive roller 5A is positioned upstream of the arrow indicating the paper conveyance direction, and the left drive roller 5B is positioned downstream. A conveyor belt 7 is wound around the right drive roller 5A and the left drive roller 5B.

  The guide roller 6 is in contact with the upper portion of the right drive roller 5A so that the transport roller 8 is pressed from above on the intermediate position between the right drive roller 5A and the left drive roller 5B. 7 is rotated in the same direction as the moving direction.

  The sheet is sandwiched between the guide roller 6 and the right drive roller 5A, passes between the transport roller 8 and the transport belt 7, and is discharged to the downstream tray or discharge stack unit. Alternatively, in the case of double-sided copying, it goes around a double-sided conveyance path (inversion path R3 in the example shown in FIG. 10 described later). At this point, the sheet temperature is about 150 ° C., which is a feature of this example. It is cooled to room temperature by the cooling device 88.

  In FIG. 1, the cooling device 88 includes a conveyance roller 8 and a conveyance belt 7, and the conveyance belt 7 is driven by two drive rollers (the right drive roller 5 </ b> A and the left drive roller 5 </ b> B). 2A and 2B show an outline of the transport roller 8. The cross section of FIG. 2A shows the cross section of the XX arrow of FIG. 2 (a) and 2 (b), the conveying roller 8 has a hollow tubular inside of the rotating portion 8R, and is rotatably fitted to a non-rotating pipe 82 through a rubber ring 80 for sealing. is doing. As shown by the arrows, the fluid flows in from the left end (fluid inlet 8N) of the transport roller 8 and flows out from the opposite right end (fluid outlet 8T). Since the transport roller 8 (specifically, the roller 8R) rotates as shown in FIG. 1, it can be rotated by a rubber ring 80, which is a rotary sealing material, and leakage is prevented.

  The temperature of the fluid passing through the transport roller 8 is controlled so as to be circulated, heat exchanged on the way, cooled, and the heat of the transport roller 8 taken away. Accordingly, the sheet is cooled while the sheet passes through the nip portion between the conveyance belt 8 and the conveyance roller 8 in FIG.

  Although the conventional heat pipe method could not cool the paper of the copying machine exceeding about 150 cpm, this method can sufficiently cool the paper even at 150 cpm or more, and the double-sided productivity in the high-speed machine is improved and the blocking phenomenon is caused. Problems such as paper sticking have been resolved, and quality has been further improved.

[2] Second Embodiment In the first embodiment, only the transport roller 8 is cooled by the internal fluid. On the other hand, in this example, the transport belt 7 in contact with the transport roller 8 is also used as a cooling means. Since the conveyance belt 7 presses the sheet against the conveyance roller 8 with its tension, the conveyance belt 7 itself also rises in temperature due to heat conduction. Therefore, the paper cooling effect by the transport belt 8 is lost when the transport belt 7 is heated.

Therefore, (in this example, the right drive roller 5A, the left drive roller 5B) 2 pieces of driving rollers for driving the conveyor belt 7 a hollow roller over like the conveying roller 8 and the at least one of, the hollow roller It is made to cool by flowing a fluid inside. Since the structure of the hollow tube conforms to the transport roller 8 shown in FIG.

  The right drive roller 5 </ b> A and the left drive roller 5 </ b> B drive the conveyance belt 7 and convey the sheet together with the conveyance roller 8 to a discharge or duplex copying station. In order to efficiently cool the temperature of the sheet, any or all of the right driving roller 5A and the left driving roller 5B that support the conveying belt 7 are used, so that the sheet opposite to the surface facing the conveying roller 8 is used. The surface can also be cooled. By cooling the transport belt driving rollers (right drive roller 5A, left drive roller 5B), the transport belt 7 is also cooled by heat conduction, and the paper is cooled from both sides, enabling effective cooling. It was. In this example, the two rollers are cooled. However, when another roller that supports the conveyance belt 7 is added, the conveyance belt 7 can be cooled by making the roller hollow.

  As a result, it is possible to cool from both sides of the paper, further increasing the cooling effect and preventing the paper from curling, further improving the reliability.

[3] Third Embodiment In the examples so far, the hollow tubular transport roller 8, the right drive roller 5A, the left drive roller 5B, etc. can be cooled using a liquid as a fluid passing through the inside. Since the liquid temperature also rises due to the circulation of the liquid, the cooling efficiency may decrease. Therefore, in this example, the temperature of the liquid is controlled so that the cooling efficiency is always the best.

  The liquid is circulated to cool the rollers such as the hollow tubular transport roller 8, the right drive roller 5 </ b> A, the left drive roller 5 </ b> B, and then the rollers and the paper are contacted directly or indirectly via the transport belt 7 to cool. However, when the copy speed exceeds 100 cpm, the temperature of the circulating fluid gradually increases. Therefore, in order to always maintain the cooling performance by controlling the liquid temperature of the liquid passing through the transport roller 8, the right drive roller 5A, the left drive roller 5B, etc., a temperature adjusting device is provided in the liquid reflux system.

  FIG. 3 shows an overview of the system. The basic requirements of the system are that the circulation pump 9, the heat exchanger 10, and the roller 11 (specifically, the transport roller 8, the right drive roller 5A, the left drive roller 5B, etc. are schematically shown here and these rollers. , Etc.) and the like are connected and connected in a loop shape by the pipe 120.

  Empirically, if the temperature of the fluid is liquid and the temperature control device (configuration including the heat exchanger 10) is controllable to a temperature rising from room temperature to within 10 ° C, there will be no problems as described later. Therefore, the performance of the temperature control device (heat exchanger 10) is also set to have the ability to suppress the liquid temperature to a temperature rise within 10 ° C. from room temperature.

  According to this example, when the circulating liquid is used as the refrigerant, the sheet cooling temperature does not decrease to a predetermined 80 ° C. or lower when the liquid temperature rises by 10 ° C. or more from room temperature, and the cooling effect decreases. In addition, the reliability of the seal of the roller rotating part is impaired, and problems such as liquid leakage occur. Therefore, in the present example, the above problem can be solved by controlling the temperature rise of the liquid temperature to 10 ° C. or less.

[4] Fourth Embodiment In this example, the liquid that cools the hollow tubular transport roller 8, the right drive roller 5A, the left drive roller 5B, and the like is cooled by natural air cooling that is accompanied by a tank that boules the liquid and a radiation fin. Cool with a heat exchanger. A heat dissipating fin is provided on the side of the tank that pools the liquid that comes into contact with the outside air, and air cooling is performed by natural convection.

  The heat exchanger 10-1 shown in FIG. 4 is an example of the heat exchanger 10 in FIG. 3, and includes a tank 10-1T for a liquid pool and a heat radiation fin 10-1F for natural air cooling. In the figure, reference numeral 10-1N denotes a liquid inlet. Although not shown in the figure on the opposite side to the liquid inlet 10-1N, there is a liquid outlet. These liquid inlet 10-1N and liquid outlet are connected with the piping 120 shown in FIG. The size of the heat exchanger 10-1 shown here can be arbitrarily increased to the size of the back cover of the main body (exterior cover of the heat exchanger 10-1). In other words, by increasing the pooled liquid up to the size of the exterior cover on the back, the air cooling area can be increased, so that the liquid temperature can be effectively lowered. The temperature can be adjusted by changing the cooling capacity according to the number and size of the fins. The heat exchanger 10-1 by natural air cooling using such a radiation fin 10-F does not use electric power and has a large energy saving effect. The liquid temperature was within 8 ° C. from room temperature, and the temperature control was good.

[5] Fifth Embodiment This is an example in which the performance of the heat exchanger 10-1 in the fourth embodiment is further improved. In other words, even more efficient cooling is possible by the forced air cooling method, which can be cooled by an air cooling fan in the natural air cooling method.

  FIG. 5 shows an example of the heat exchanger 10-2 for forced convection. This heat exchanger 10-2 is an example of the heat exchange device 10 in FIG. 3, and includes a tank 10-2T for a liquid pool and a radiating fin 10-2F for natural air cooling. The liquid inlet is denoted by reference numeral 10-2N. Although not shown on the opposite side to the liquid inlet 10-2N, there is a liquid outlet. The liquid inlet 10-2N and the liquid outlet are connected to the pipe 120 shown in FIG. Further, a convection fan 10-2Fa is provided as a cooling means for forced air cooling at the lower part of the main body. This forced convection fan 10-2Fa is a long cross flow fan. In addition, an axial flow fan may be used as well as a long cross flow fan as in this example. The cooling temperature can be controlled by selecting a fan.

  in this way. By cooling by forced air cooling, the rise in the liquid temperature is suppressed within 6 ° C., and a sufficient paper cooling effect can be obtained. In addition, the fan input voltage is also controlled by monitoring the liquid temperature, so energy can be saved.

[6] Sixth Embodiment In this example, a liquid is cooled using a Peltier device as an electronic cooling means. This is a positive cooling means suitable for use when the cooling of the liquid temperature is not in time with the cooling means described in the above embodiments.

  FIG. 6 shows a temperature control device using a Peltier element. This temperature control device has a liquid tank 12 for pooling liquid. The liquid inlet is indicated by reference numeral 12N. Although not shown on the side opposite to the liquid inlet 12N, there is a liquid outlet. These liquid inlet 12 and liquid outlet are connected to the pipe 120 shown in FIG. A Peltier element 110 is bonded through silicone 13 having good thermal conductivity in contact with the liquid tank 12. The Peltier element 110 exhibits a cooling function by applying DC 12V. The opposite side of the Peltier element 110 generates heat, and this is dissipated by the heat sink 14 and the fan 15 in contact with the Peltier element 110. By this cooling, the liquid tank 12 can be cooled to room temperature or lower, and the high-speed image forming apparatus can be efficiently cooled.

  For an ultra-high speed machine having a processing capacity of 150 cpm, the air cooling method in the above-described embodiment does not sufficiently cool the liquid. Therefore, as in this example, the liquid is cooled by electronic cooling means such as the Peltier element 110 to suppress the temperature rise. This method enables stable cooling of the paper during continuous copying on a high-speed machine.

[7] Seventh Embodiment This example is another example of the temperature control device in the temperature control device (third embodiment) capable of controlling the liquid temperature to be within 10 ° C. from the room temperature, and is the most efficient. Cools well. This is particularly effective when the liquid temperature rises significantly. This will be described with reference to FIG. In this example, a refrigeration cycle system using a small compressor 16 is applied to cooling the liquid tank 17 integrated with the evaporator 180. A compressor 16, an evaporator 180 integrated with the liquid tank 17, and a heat exchange condenser 19 are connected by a gas pipe 130. The heat exchange condenser 19 is cooled by the fan 20.

  When the refrigerant in the vaporized state is compressed by the compressor 16, the refrigerant enters a heat exchange condenser 19 in a semi-liquefied state by generating high heat, is cooled by the fan 20, and is further sent to the evaporator 180 in a state where liquefaction proceeds.

  The liquefied refrigerant is injected into the evaporator 180 from a minute nozzle hole and is vaporized at once. The vaporized refrigerant takes the heat of the liquid in the liquid tank 17 to gasify and proceeds to the compressor 16. If the liquid tank 17 is replaced with the heat exchanger 10 shown in FIG. 3, the liquid flowing through the pipe 120 shown in FIG. 3 can be efficiently cooled.

  By using this cooling method, the cooling effect more than the Peltier element in the example of FIG. 6 was obtained. This example is applied to the highest model among high-speed image forming apparatuses to obtain sufficient performance, and enables efficient image copying with efficient cooling.

[8] Eighth Embodiment In this example, the fluid flowing through the pipe 120 with the rotation of the rollers such as the hollow tubular transport roller 8, the right drive roller 5A, and the left drive roller 5B is efficiently and well with the inner walls of these rollers. A partition plate is provided to control the flow in a spiral shape so that proper heat transfer is possible.

  FIG. 8 shows a cross section perpendicular to the axis of the roller 11 exemplified by the hollow tubular conveying roller 8, the right driving roller 5A, the left driving roller 5B, and the like, and eight partition plates at equal intervals on the inner wall. 30 (fin) is formed. These partition plates 30 (fins) are fins that spirally rotate the liquid flowing in the axial direction (direction penetrating through the drawing sheet).

  Due to the function of the partition plate 30, the liquid in the roller 11 performs a spiral motion, that is, spirals and rotates to advance. Thus, regardless of the liquid or gas, the flow is generated along the inner wall of the hollow tube, so that the heat transfer efficiency between the fluid and the inner wall of the roller is remarkably improved and the cooling efficiency can be improved.

[9] Ninth Embodiment In this example, a double pipe is used to allow two types of fluid to flow in the pipe of the roller. Thereby, cooling, such as a liquid and gas, becomes possible efficiently.

  A specific example is shown in FIG. FIG. 9 shows a cross section perpendicular to the axis of the roller 11 exemplified by the hollow tubular conveying roller 8, the right driving roller 5A, the left driving roller 5B, and the like, and eight partition plates at equal intervals on the inner wall. 30 (fin) is formed. These partition plates 30 (fins) are fins that spirally rotate the liquid flowing in the axial direction.

  The feature of this example is that another tube 33 is concentrically held at the center of the roller 11. Outside the tube 33, as described in the eighth embodiment, the function of the partition plate 30 causes the liquid in the roller 11 to travel in a direction penetrating the paper surface while performing a spiral motion.

  On the other hand, another fluid can flow inside the tube 33. Thus, by making the inside of the roller 11 double, the liquid may flow outside the tube 33 and the air may flow inside, or vice versa depending on the situation. Thus, the cooling function can be efficiently exhibited by using the liquid and the gas at the same time.

  For example, the efficiency of sheet cooling can be improved by flowing liquid inside the double pipe (pipe 33) and flowing air outside the double pipe (pipe 33) (roller side). On the contrary, it is possible to flow gas inside the double pipe (tube 33) and liquid outside (roller side), and it is also possible to select the fluid inside and outside depending on which of these fluids is cooled. For example, when cooling the gas, it is possible to exchange heat efficiently inside the roller with a double tube (the gas is passed outside the tube 33 and the temperature is lower than that of the liquid, Heat removal can be realized in a shorter time than circulation of liquid alone.

[10] Tenth Embodiment In this example, air is used as a cooling medium, and since pressure loss is large when air is blown into the roller 11, an air pump is provided and forcedly circulated. When the fluid flowing in the roller is a gas such as air, cooling is possible by blowing with an air pump. In this example, the outside air can be directly blown into the roller 11, and a cooling effect can be obtained even with a simple mere cylindrical structure without using fins or double tubes as shown in FIGS.

[11] Eleventh Embodiment The cooling device described so far is used in an image forming apparatus having a thermal fixing device that fixes an unfixed image on a sheet at least by heat. An example of this image forming apparatus will now be described. FIG. 10 shows an overall schematic configuration of an internal mechanism of an electrophotographic copying machine including the thermal fixing device 32 according to the present invention.

  Reference numeral 100 in the drawing denotes a copying machine main body. The copying machine main body 100 has an image reading device 200 mounted thereon and placed on a sheet bank 300. An automatic document feeder 400 is mounted on the image reading apparatus 200 so as to be opened and closed up and down with the back side as a fulcrum.

  The copying machine main body 100 is provided with a drum-shaped photosensitive member 18 as an image carrier. Around the photoconductor 18, from the charging device 19 arranged on the left side in the figure, in the rotation direction (counterclockwise) A of the photoconductor 18, the developing device 72 on the lower side, the transfer device 73 on the right side, and the upper side. A cleaning device 74 is arranged.

Of these, the developing device 72, as a toner, using a polymerization toner produced by a polymerization method, we visualize the electrostatic latent image on the photosensitive member 18 attached with the polymerized toner developing roller over. The transfer device 73, constituted by turning over the transfer belt 77 between the upper and lower rollers over 75 and 76, formed by pressing the transfer belt 77 on the circumferential surface of the photoreceptor 18 at the transfer position B.

  In FIG. 10, what is provided on the left side of the charging device 19 and the cleaning device 74 is a toner supply device 20 for supplying new toner to the developing device 72.

  In addition, a sheet conveying apparatus C that conveys a sheet S sent from a sheet cassette 61 (described later) of the sheet bank 300 from below to the stack position via the transfer position B is provided inside the copying machine main body 100. The sheet conveying apparatus C includes a supply path R1, a manual feed path R2, and a sheet conveyance path R.

The sheet transport path R, a resist roller over 21 upstream position of the photosensitive member 18. Further, a thermal fixing device 3 is provided at a downstream position of the photoconductor 18. The thermal fixing device 3 has the same configuration as that described with reference to FIG.

  Further downstream of the heat fixing device 3, the cooling device according to the present invention already described, that is, the right driving roller 5A, the left driving roller 5B, the guide roller 6, the conveying belt 7, the conveying roller 8, and the like shown in FIG. Is arranged. The image-formed paper cooled by the cooling device is discharged to a discharge stack portion (discharge position) 39 and stacked.

The copying machine main body 100 is provided with a switchback device 42 on the right side in the drawing. Switchback device 42 that is branched from the discharge branch claw 34 position of the sheet conveying path R, the inverting path R3 for guiding until the switch-back position 44 with a pair of switchback rollers over 43, from the switchback position 44, again the sheet conveying comprising a sheet transport device D having a re-conveying path R4 guided to the registration roller over 21 tracts R. Its sheet conveying device D, comprising a plurality of sheet conveying rollers over 66 for conveying the sheet.

  A laser writing device 47 is provided on the left side of the developing device 72 in the drawing. The laser writing device 47 is provided with a laser light source (not shown), a scanning polygon mirror 48, a polygon motor 49, a scanning optical system 50 such as an fθ lens, and the like.

  The image reading apparatus 200 is provided with a light source 53, a plurality of mirrors 54, an imaging optical lens 55, an image sensor 56 such as a CCD, and the like. A contact glass 57 is provided on the upper surface.

The automatic document feeder 400 on the contact glass 57 is provided with a document setting table (not shown) at the document placement position and a document stack table (not shown) at the discharge position. In addition, a sheet conveyance device having a document conveyance path (not shown) that conveys a document sheet from a document setting table to a document stacking table through a reading position on the contact glass 57 of the image reading device 200 is provided. Its sheet conveying apparatus, comprising a plurality of sheet conveying rollers over (not shown) for conveying the original sheet.

The sheet bank 300 includes therein a plurality of sheet cassettes 61 that store sheets S as sheet-like media, for example, transfer sheets, OHP films, and the like. Each sheet cassette 61, call roller over 62 correspond respectively, the supply roller over 63, providing the separation roller over 64. The above-described supply path R1 leading to the sheet conveyance path R of the apparatus main body 100 is formed on the right side of the multi-stage sheet cassette 61 in the drawing. Also supply path R1, comprises several sheet conveying roller over 66 for conveying the sheet (sheet conveying rotating body).

The copying machine main body 100 is provided with a manual feed unit 68 on the right side in the drawing. A manual feed tray 67 is provided in the manual feed unit 68 so as to be openable and closable, and includes the above-described manual feed path R <b> 2 that guides a manual sheet set on the manual feed tray 67 to the sheet conveyance path R. Similarly to the manual feed tray 67, the calling roller over 62 and supply roller over 63, providing the separation roller over 64.

  When copying using this copying machine, a main switch (not shown) is turned on and a document is set on a document setting table of the automatic document feeder 400. In the case of a book document, the automatic document feeder 400 is opened, a document is set directly on the contact glass 57 of the image reading device 200, and the automatic document feeder 400 is closed and pressed.

When the pressing of the switch, when set an original on the automatic document feeder 400, document through the document conveying path by the sheet conveying roller over, read image Move to top contact glass 57 200 Is driven to read the document contents and discharge them onto the document stacking table. On the other hand, when the document is set directly on the contact glass 57, the image reading apparatus 200 is immediately driven.

  When the image reading apparatus 200 is driven, the image reading apparatus 200 moves the light source 53 along the contact glass 57, reflects light from the light source 53 on the original surface on the contact glass 57, and reflects the reflected light to a plurality of light sources 53. The light is reflected by a mirror 54, passes through an imaging optical lens 55, is put in an image sensor 56, and the image content is read by the image sensor 56.

At the same time, by rotating the photosensitive member 18 by a photoreceptor driving motor (not shown), first, in the illustrated example by uniformly charging the surface by the charging device 19 using a charging roller over, then the above-described image reading apparatus 200 The laser writing device 47 irradiates a laser beam in accordance with the contents of the document read in step (b) and writes the image on the surface of the photosensitive member 18. Then, an electrostatic latent image is formed on the surface of the photosensitive member 18. Visualize the electrostatic latent image.

At the same time when pressing the start switch, feed the paper S by the call roller over 62 from the inside of the sheet cassette 61 corresponding to the selected size of the plurality of sheets cassettes 61 provided in multiple stages in the sheet bank 300, followed by the supply roller over 63 , placed in the supply path R1 while conveying separated one by one by a separation roller over 64, are transported by a sheet transport roller over 66 leads to the sheet conveying path R, and are bumped against a resist roller over 21. Then, the resist roller over 21 rotates timed to the rotation of the toner image visualized on the photosensitive member 18 described above, fed to the right of the photoconductor 18.

Or by opening the manual feed tray 67 of the manual sheet feeding section 68, feeds the manual feed sheet set thereon manual feed tray 67 by calling rollers over 62, followed by supply roller over 63, is separated one by one by a separation roller over 64 into a manual feed path R2 while conveying, are transported by a sheet transport roller over 66 leads to the sheet conveying path R, also by the registration roller over 21 timed to the rotation of the photosensitive member 18 to the right side of the photoreceptor 18 And send it in.

  Then, the toner image on the photoconductor 18 is transferred to the paper S fed to the right side of the photoconductor 18 at the transfer position B by the transfer device 13 in the illustrated example to form an image. Residual toner on the photoconductor 18 after image transfer is removed and cleaned by a cleaning device 74, and a residual potential on the photoconductor 18 is removed by a neutralization device (not shown) to prepare for the next image formation starting from the charging device 19. .

  On the other hand, the sheet S after the image transfer is conveyed by the transfer belt 77, detected by a sensor (not shown), and then put into the heat fixing device 3 and passed between the heated fixing roller 1 and the pressure roller 2. The toner image on the paper S is fixed by applying heat and pressure by them. Then, it discharges | emits on the discharge | emission stack part 39 via the cooling device of this invention already demonstrated, and stacks there.

When images are transferred on both sides of the paper S, the discharge branch claw 34 is switched. Then, the sheet-like medium and transferring the toner image to a surface, placed from the sheet conveying path R to the inverting path R3, are transported by a sheet transport roller over 66 put to the switchback position 44, switch back by the switchback roller over 43 It reversed placed in re-conveying passage R4 by, again guided to the sheet conveying path R is conveyed by the sheet conveying roller over 66 to transfer the image on the reverse side of the transfer material in the same manner as described above. As described in the background section, it is particularly important to sufficiently cool the paper toner in duplex copying. However, the paper cooling device of the present invention eliminates blocking phenomenon, curling, jamming, and the like. It is possible.

It is a schematic explanatory drawing of the cooling device and heat fixing device part of this invention. 2A is a perspective view of the transport roller, and FIG. 2B is a cross-sectional view of the transport roller. It is a schematic block diagram of a temperature control apparatus. It is a perspective view of a heat exchanger. It is a perspective view of a heat exchanger. It is a perspective view of the temperature control apparatus using a Peltier device. It is the schematic of a refrigerating cycle system. It is sectional drawing of a roller. It is sectional drawing of a roller. 1 is a schematic configuration diagram of an image forming apparatus.

Explanation of symbols

3 Thermal fixing device 8 Transport roller S Paper

Claims (9)

In a cooling device for cooling a sheet-like medium on which toner is fixed by a heat fixing device,
A transport roller for transporting the sheet-like medium;
A conveyance belt that conveys the sheet-like medium by pressing the sheet-like medium to the conveyance roller;
A plurality of belt driving rollers for driving the conveyor belt,
At least one of the plurality of belt drive rollers and the transport roller,
With a tubular structure through which liquid fluid flows inside the roller,
The liquid fluid flows from one end of the tubular structure roller,
The liquid fluid flows out from the opposite end ,
By the conveyance belt cooled by the drive roller and the conveyance roller,
Comprising a configuration for cooling the sheet-like medium from both sides;
A nip portion in a surface state is formed by pressing the conveyance roller toward the conveyance belt, and the sheet-like medium is conveyed and cooled in the nip portion in the surface state. apparatus. The cooling device according to claim 1, wherein
A cooling device comprising a temperature adjusting device capable of controlling the liquid temperature to a rising temperature within 10 ° C. from room temperature when the fluid is liquid. The cooling device according to claim 2, wherein
The cooling apparatus according to claim 1, wherein the temperature control device includes a tank for pooling liquid and a natural air-cooling cooling means attached to the heat dissipating fins. The cooling device according to claim 2, wherein
The cooling apparatus according to claim 1, wherein the temperature adjusting device includes a tank for pooling liquid, a radiating fin, and a forced air cooling cooling means associated with an air cooling fan. The cooling device according to claim 2, wherein
The cooling device, wherein the temperature control device includes a tank for pooling liquid and an electronic cooling means. The cooling device according to claim 2, wherein
The cooling device, wherein the temperature control device includes a compressor, an evaporator, and a condenser. The cooling device according to any one of claims 1 to 6,
The inner wall of either or both of the transport roller and the belt drive roller has a structure in which a partition plate is provided in a spiral shape in the longitudinal direction of the roller so that the fluid flows in a spiral motion as the roller rotates. A cooling device characterized by. The cooling device according to any one of claims 1 to 6,
Regarding the tubular structure of the roller, the cooling apparatus is characterized in that the pipe has a double pipe structure and a fluid flows to the outside and the inside of the double pipe. In an image forming apparatus having a heat fixing device for fixing an unfixed image to a sheet-like medium by at least heat,
The image forming apparatus according to claim 1, wherein a cooling device that cools the sheet-like medium on which the toner is fixed by the heat fixing device is the one according to claim 1.

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