JP4434878B2 - Image forming apparatus cooling apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a cooling device and an image forming apparatus for an image forming apparatus, and more particularly, to an image carrier, an endless intermediate transfer belt for transferring and forming an image formed on the image carrier, and an image transferred. A fixing device that fixes the transfer material, and is disposed between the fixing device and the intermediate transfer belt, and moves the heat of the fixing device from the vicinity of the intermediate transfer belt by the heat conveying member, and the intermediate The present invention relates to an image forming apparatus provided with a heat dissipating part that dissipates heat from a fixing device.

  2. Description of the Related Art Today, electrophotographic apparatuses, which are image forming apparatuses, are increasingly capable of color printing, such as color copiers and color printers, according to market demands.

  A color electrophotographic apparatus is provided with a developing device of a plurality of colors around one photoconductor, and a toner is attached by these developing devices to form a composite toner image on the photoconductor, and the toner image is transferred. A so-called one-drum type that records a color image on a sheet, and a plurality of photoconductors provided side by side are each provided with a developing device, and a single-color toner image is formed on each photoconductor. There is a so-called tandem type that sequentially transfers and records a composite color image on a sheet.

  Comparing the 1-drum type and the tandem type, the former has only one photoconductor, so that there is an advantage that the size can be relatively reduced and the cost can be reduced. Since the full-color image is formed by repeating the image formation, it is difficult to increase the image formation speed. On the other hand, the latter, on the other hand, has a drawback that the apparatus becomes large and the cost is high, but it is easy to speed up image formation.

  In recent years, tandem type electrophotographic apparatuses have attracted attention because full-color printing is desired to be printed at a high speed equivalent to monochrome printing. The tandem type electrophotographic apparatus is a direct transfer type, and images on each photoconductor are transferred by a transfer device, and yellow (Y), cyan (C), magenta (M), and black (K) images are transferred by a sheet conveying belt. Some of them are sequentially transferred to the conveyed sheet. As shown in FIG. 4, as an indirect transfer system, images on the photoreceptors 100Y, 100C, and 100M of yellow (Y), cyan (C), magenta (M), and black (K) are primary. After the image is sequentially transferred to the intermediate transfer belt 200 by the transfer device, the images on the intermediate transfer belt 200 are collectively transferred to the transfer material 400 by the secondary transfer device.

  Comparing the direct transfer type and the indirect transfer type, the former is such that the position of the conveying sheet fluctuates on the sheet conveying belt in order to directly transfer the transferred material 400 from each photoconductor. If it does, the image written in each photoconductor may shift | deviate.

  On the other hand, in the latter, the secondary transfer position can be set relatively freely, and even when the position of the transferred material 400 to be conveyed fluctuates, each image is transferred to the material to be transferred 400 when each image is transferred. The image written by the body 100 has already been matched, and there is an advantage that the image does not shift even if the transfer material 400 changes.

  In view of the above, recently, an indirect transfer type of tandem type electrophotographic apparatus has attracted attention. At this time, as shown in FIG. 4, from the viewpoint of reducing the machine size in the lateral direction, the fixing device 800 is configured to be pulled down to the lower side of the intermediate transfer belt 200 together with the higher density inside the machine. The fixing device 800 is disposed close to the 200. In addition, the amount of heat generated inside the machine increases due to a demand for high-speed machines, and the belt device as an image forming unit may be thermally affected by the fixing device 800 as a heating element. In view of such demands, image forming apparatuses are desired to save space and increase cooling efficiency.

  As an image forming apparatus as described above, Patent Document 1 describes an image forming apparatus that performs heat insulation from a fixing device to an image forming unit. That is, the first air for fixing another cover on the upper cover of the heat fixing device and flowing the warmed air inside the heat fixing device to the outside between the two covers. In addition to forming a flow path, a second air flow path is formed between the cover and a catch pan that receives toner spilled from the developing device. ing.

  Patent Document 2 describes an image forming apparatus that performs heat insulation from a fixing device to an image forming unit. That is, in the image forming apparatus configured to prevent heat conduction and radiation from the fixing unit to the image forming unit by providing a heat shield between the image forming unit and the fixing unit, A stay made of a good thermal conductor provided on the side of the head and a cover made of a heat insulating material that covers the lower portion of the stay and forms a sealed or substantially sealed space. It is described that a duct portion is provided to form a flow path of fresh air from outside the apparatus in cooperation with a wall.

  Furthermore, in Patent Document 3, a heat carrying member is provided between the fixing device halfway transfer belt, and the heat received from the fixing device by the heat carrying member is moved from the vicinity of the intermediate transfer belt to a place away from the intermediate transfer belt. A tandem color image forming apparatus is disclosed in which the heat of a fixing member is radiated by a provided heat radiating portion.

  Japanese Patent Application Laid-Open No. H10-260260 describes that the heat radiating unit has a function of releasing heat carried from the transferred material after passing through the fixing device by the transferred material cooling device.

Patent Document 4 describes that the transfer material cooling device and the fixing device are thermally insulated, and that the cooling fins face upward.
JP 2000-227730 A JP 2001-183959 A JP 2003-091189 A JP 11-338332 A JP 11-338333 A

  Here, as a cause of color misregistration and banding, which is one of the image degradation of the tandem type color image forming apparatus, the expansion and contraction of the intermediate transfer belt occurs between the stations due to the heat generated from the fixing device, and the expansion of the pixels of each color. The rate is not good. Accordingly, the present invention reduces the heat transfer from the fixing device to the intermediate transfer belt, prevents the fixing device from having a thermal influence on the intermediate transfer belt, and provides a cooling device for the image forming apparatus capable of forming a good image. An object is to provide an image forming apparatus.

The invention according to claim 1, the heat from the fixing device of the image forming apparatus, from the intermediate transfer belt near, image formation with a heat conveying member for moving the heat dissipating part provided away from the said intermediate transfer belt in the cooling device of the apparatus comprises a transfer material cooling device for cooling the transfer material which is fixed to al Re image heated by the fixing device, and the heat conveying member, between said transfer material cooling device, wherein disposing an insulating portion to prevent the heat carrying member by the heat of the transfer material cooling apparatus is heated, the heat radiation member, said the radiating heat was carried off is specifically by the heat conveying member to the outside of the apparatus And a cooling device for the image forming apparatus.

According to a second aspect of the invention, the cooling device of an image forming apparatus according to claim 1, wherein between the transfer material cooling device and the front Symbol fixing device, wherein the transfer material cooling device is heated by the heat of the fixing device It is characterized by having a fixing heat insulating part for preventing the above.

According to a third aspect of the present invention, in the cooling apparatus for an image forming apparatus according to the first or second aspect, the heat radiating portion is provided with a heat radiating fin, and the heat radiating fin is formed with its tip facing upward. To do.

A fourth aspect of the present invention, in the cooling apparatus of any one of the image forming apparatus of claims 1 to 3, wherein the heat carrying member is characterized Oh Rukoto a heat pipe.

According to a fifth aspect of the present invention, there is provided an image carrier, an endless intermediate transfer belt to which an image formed on the image carrier is transferred, and fixing of the image onto a transfer material onto which an image is transferred from the intermediate transfer belt. A fixing device that performs heat transfer, a heat carrying member that is disposed between the fixing device and the intermediate transfer belt and moves heat of the fixing device from the vicinity of the intermediate transfer belt, and the intermediate transfer belt. And a heat radiating unit for radiating heat from the fixing device, the image forming apparatus comprising a transfer material cooling device for cooling the transfer material heated by the fixing device and fixing the image, and the heat transport Between the member and the transferred material cooling device, a heat insulating portion for preventing the heat carrying member from being heated by the heat of the transferred material cooling device is disposed, and at the heat radiating portion, by the heat carrying member The heat that has been carried away An image forming equipment which is characterized that you heat dissipation.

According to a sixth aspect of the present invention, in the image forming apparatus of the fifth aspect, the fixing for preventing the transfer material cooling device from being heated by the heat of the fixing device between the transfer material cooling device and the fixing device. It characterized that you have placed a heat insulating portion.

According to a seventh aspect of the present invention, in the image forming apparatus according to the fifth or sixth aspect, the heat dissipating part is provided with a heat dissipating fin, and the heat dissipating fin is formed with its tip facing upward .

The invention of claim 8, in any of the image forming apparatus of claims 5 to 7, wherein the heat carrying member is characterized Oh Rukoto a heat pipe.

The invention of claim 9, Oite to any one of the image forming equipment according to claim 5 to 8, having a configuration of a tandem type having a plurality of said image bearing member, characterized in that it is possible color image formation And

According to the present invention, the heat removed from the transfer material carried by the transfer material cooling device is dissipated, so that the intermediate transfer belt and the fixing device can be insulated and the transfer material can be insulated without newly providing a heat radiating portion. Cooling can be performed with high efficiency .

  The best mode for carrying out the present invention will be described below with reference to the embodiments shown in the drawings.

  FIG. 1 is a schematic cross-sectional view of a tandem type indirect transfer type copying apparatus to which the present invention is applied. In the figure, P is a copying machine main body, 120 is a paper feed table, 130 is a scanner, and 140 is an automatic document feeder (ADF). The copying apparatus main body P is placed on the paper feed table 120, the scanner 130 is mounted on the copying apparatus main body P, and the ADF 140 is further mounted thereon.

  In the copying apparatus main body P, an endless belt-like intermediate transfer belt 200 is provided at the center and is wound around four support rollers 201, 202, 203, and 204 so that it can be rotated and conveyed clockwise in the drawing. In this example, an intermediate transfer body cleaning device 17 that removes residual toner remaining on the intermediate transfer belt 200 after image transfer is provided to the left of the second support roller 202 among the four support rollers.

  Further, yellow (Y) along the conveying direction of the intermediate transfer belt 200 so as to be positioned on the intermediate transfer belt 200 between the first support roller 201 and the second support roller 202 among the four support rollers. , Cyan (C), magenta (M), and black (K) four image forming units 18Y, 18C, 18M, and 18K are arranged side by side to form a tandem type image forming apparatus 20. An exposure device 21 is provided above the image forming device 20 as shown in the figure.

  On the other hand, a secondary transfer device 22 is provided on the opposite side of the image forming device 20 with the intermediate transfer belt 200 interposed therebetween. In the illustrated example, the secondary transfer device 22 is configured such that a secondary transfer belt 24, which is an endless belt, is stretched around a roller 300, and the secondary transfer device 22 is transferred to the third support roller 16 via the intermediate transfer belt 200. The belt 24 is disposed so as to be pressed against it, and the image on the intermediate transfer belt 200 is transferred to a sheet as a transfer material.

  Next to the secondary transfer device 22, a fixing device 800 for fixing the transferred image on the sheet is provided. The fixing device 800 is configured by pressing the pressure roller 27 against the fixing belt 26 which is an endless belt. The secondary transfer device 22 described above has a sheet transport function for transporting the image-transferred sheet to the fixing device 800. Of course, a transfer roller or a non-contact charger may be disposed as the secondary transfer device 22, but in such a case, it is difficult to provide this sheet conveyance function together.

  In this example, a cooling device 900 is provided between the fixing device 800 and the intermediate transfer belt 200, and heat generated from the fixing device 800 and directed toward the intermediate transfer belt 200 by radiation and convection is high in the ambient temperature. From the space between the intermediate transfer belt 200 and the left side of the machine where the ambient temperature is low.

  In the example shown in the figure, sheet reversal for reversing the sheet in order to record images on both sides of the sheet in parallel with the above-described image forming device 20 below the secondary transfer device 22 and the fixing device 800. A device 28 is provided.

  The operation when making a copy using this color electrophotographic apparatus will be described. The document is set on the document table 30 of the automatic document feeder 140, or the automatic document feeder 140 is opened and the document is set on the contact glass 32 of the scanner 130. The automatic document feeder 140 is closed and pressed by it.

  When a start switch (not shown) is pressed, when a document is set on the automatic document feeder 140, the document is transported and moved onto the contact glass 32, and then the document is set on the other contact glass 32. When this occurs, the scanner 130 is immediately driven to cause the first traveling body 33 and the second traveling body 34 to travel. Then, the first traveling body 33 emits light from the light source and further reflects the reflected light from the document surface toward the second traveling body 34, and is reflected by the mirror of the second traveling body 34 and passes through the imaging lens 35. The document is placed in the reading sensor 36 and the original content is read.

  When a start switch (not shown) is pressed, one of the support rollers 14, 15, and 16 is driven to rotate by the drive motor (not shown), and the other two support rollers are driven to rotate. 200 is rotated and conveyed. At the same time, the photoconductors 100Y, 100C, 100M, and 100K are rotated by the individual image forming means 18, and black, yellow, magenta, and cyan single-color images are formed on the photoconductors 100Y, 100C, 100M, and 100K, respectively. Then, as the intermediate transfer belt 200 is conveyed, the monochrome images are sequentially transferred to form a composite color image on the intermediate transfer belt 200.

  Next, the cooling device 900 according to this example will be described in more detail. In this example, as shown in FIGS. 1 and 3, the images formed on the photoreceptors 100 </ b> Y, 100 </ b> C, 100 </ b> M, and 100 </ b> K for each color are primarily transferred to the intermediate transfer belt 200, and a plurality of colors are formed on the intermediate transfer belt 200. Are transferred to the transfer material 400 at the nip portion between the counter rotator 203 and the roller 300 of the secondary transfer device 22 pressurized against the counter rotator 203, and then the image is transferred by the fixing device 800. Fixing is performed. In this example, each of the photoconductors 100Y, 100C, 100M, and 100K is driven by a motor 600. Each of the photoreceptors 100Y, 100C, 100M, and 100K is accompanied by a developing device 500Y, 500C, 500, and 500K. The developing devices 500Y, 500C, 500M, and 500K are motors via gear trains 530Y, 530C, 530M, and 530K. It is driven by 600.

  In this example, as shown in FIG. 2, a cooling device 900 is provided between the fixing device 800 and the intermediate transfer belt 200, and heat generated in the direction of the intermediate transfer belt 200 by the radiation and convection is generated from the fixing device 800. From the space between the high-temperature fixing device 800 and the intermediate transfer belt 200, it is carried to the left side of the machine where the ambient temperature is low, and heat is dissipated by the heat dissipating part 920 provided there, thereby efficiently diffusing heat outside the machine. Do.

  Here, the cooling device 900 includes a heat pipe 910 that is a heat carrying member, a heat radiating unit 920, and a paper discharge cooling device 950. The heat dissipating portion 920 is formed with heat dissipating fins 921 with their tips facing upward.

  In this example, as shown in FIG. 2, the transfer material 400 heated by the fixing device 800 is removed by the discharge cooling device 950, and the transfer material 400 is discharged out of the apparatus in a state where the temperature is lowered. Is done.

  The heat carried from the transfer material 400 by the paper discharge cooling device 950 is carried to the heat radiating portion 920 of the heat pipe 910 and cooled by the heat radiating fins 921. As a result, the heat radiating part for the paper discharge cooling device 950 and the heat radiating part of the heat pipe 910 can be made common, so that the increase in the number of parts and restrictions on the layout of the apparatus can be avoided and the apparatus can be made compact. .

  Further, in this example, a heat pipe heat insulating part 951 is provided between the paper discharge cooling device 950 and the heat pipe 910, thereby preventing the heat pipe 910 from being heated by the heat of the paper discharge cooling device 950. The deterioration of the heat transport efficiency of the heat pipe 910 caused by the temperature increase in the heat transport path of the heat pipe 910 can be prevented.

  Further, in this example, a fixing heat insulating portion 952 is provided between the paper discharge cooling device 950 and the fixing device 800, and by preventing the paper discharge cooling device 950 from being heated by the heat of the fixing device 800, It is possible to prevent the deterioration of the heat transport efficiency of the paper discharge cooling device 950 caused by the temperature rise in the heat transport path of the paper discharge cooling device 950. Reference numeral 953 in the drawing denotes a side plate of the copying apparatus main body P.

  The heat dissipating fins 921 of the heat dissipating part 920 are directed upward, and the heat dissipating part 920 can be dissipated by using the ascending airflow caused by the convection of the air generated by the heat of the heat dissipating part 920, and more efficiently. The heat radiating portion 920 can be radiated.

  As described above, in this embodiment, in order to reduce image expansion and color misregistration due to partial expansion and contraction of the intermediate transfer belt of the tandem type color image forming apparatus, Focusing on the expansion, the heat of the fixing device and the paper discharge unit can be efficiently discharged so that the heat of the fixing device is not transmitted to the intermediate transfer belt.

1 is a cross-sectional view illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. 1 is a front view showing a main part of an image forming apparatus according to an embodiment of the present invention. 1 is a perspective view showing a main part of an image forming apparatus according to an embodiment of the present invention. 1 is a cross-sectional view illustrating an example of an image forming apparatus that is an object of the present invention.

Explanation of symbols

14, 15, 16 Support roller 17 Intermediate transfer member cleaning device 18 Image forming means 18Y, 18C, 18M, 18K Image forming means 20 Image forming device 21 Exposure device 22 Secondary transfer device 24 Secondary transfer belt 26 Fixing belt 27 Pressure Roller 28 Sheet reversing device 30 Document base 32 Contact glass 33 First traveling body 34 Second traveling body 35 Imaging lens 36 Sensor 100 Photoconductor 100Y, 100C, 100M, 100K Photoconductor 120 Paper feed table 130 Scanner 140 Automatic document feeder 200 Intermediate transfer belt 201, 202, 203, 204 Support roller 201 First support roller 202 Second support roller 203 Counter rotating body 300 Roller 400 Transfer material 500Y, 500C, 500M, 500K Developing devices 530Y, 530C, 530M, 530K gear train 600 Motor 800 Fixing device 910 Heat pipe 920 Heat radiation part 921 Heat radiation fin 950 Paper discharge cooling device 951 Heat pipe heat insulation part 952 Fixing heat insulation part P Copying machine main body

Claims (9)

The heat from the fixing device of the image forming apparatus, from the intermediate transfer belt near, in the cooling apparatus of an image forming apparatus provided with a heat conveying member for moving the heat dissipating part provided away from the said intermediate transfer belt,
Comprising a transfer material cooling device for cooling the transfer material which is fixed to al Re image heated by the fixing device,
Arranged between the heat carrying member and the transfer material cooling device is a heat insulating portion for preventing the heat carrying member from being heated by the heat of the transfer material cooling device ,
The heat radiation member, a cooling device of an image forming apparatus characterized by radiating heat was carried off is specifically by the heat conveying member to the outside of the apparatus. Between the front Symbol transfer material cooling device and the front Symbol fixing device claims, characterized in that by arranging the fixing insulation portion for preventing the heat of the fixing device of the transfer material cooling device is heated Item 2. A cooling device for an image forming apparatus according to Item 1. 3. The cooling device for an image forming apparatus according to claim 1, wherein the heat radiating portion is provided with a heat radiating fin, and the heat radiating fin is formed with a tip thereof facing upward . The heat conveying member cooling device according to any of the image forming apparatus of claims 1, characterized in Oh Rukoto in the heat pipe 3. An image carrier, an endless intermediate transfer belt to which an image formed on the image carrier is transferred, a fixing device for fixing the image on a transfer material onto which an image is transferred from the intermediate transfer belt, and A heat carrying member that is disposed between the fixing device and the intermediate transfer belt and moves heat of the fixing device from the vicinity of the intermediate transfer belt, and the intermediate transfer belt is provided at a location away from the fixing device. In an image forming apparatus provided with a heat radiating part that radiates heat,
A transfer material cooling device that cools the transfer material heated by the fixing device and having the image fixed thereon;
Arranged between the heat carrying member and the transfer material cooling device is a heat insulating portion for preventing the heat carrying member from being heated by the heat of the transfer material cooling device,
The heat dissipating unit, the image forming equipment characterized that you radiate heat that has been carried away by the heat conveying member to the outside of the apparatus. Wherein during the transfer material cooling device and the fixing device, according to claim 5, characterized that you have placed a fixing heat-insulating portion to prevent the the transfer material cooling device is heated by the heat of the fixing device Image forming apparatus. The image forming apparatus according to claim 5, wherein the heat dissipating part is provided with a heat dissipating fin, and the heat dissipating fin is formed with a tip thereof facing upward . The heat transport member The image forming apparatus of claims 5, characterized in Oh Rukoto in the heat pipe 7. The image forming apparatus according to claim 5 to 8, having a configuration of a tandem type having a plurality of the image bearing member, images forming device you characterized in that it is a color image formation.