JP2006171211A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of suppressing the temperature rise thereinside by a water-cooled mechanism thereby realizing the reduction of noise, and efficiently attaining a cooling by optimizing a cooling water circulation path and a circulating timing thereby saving energy consumption. <P>SOLUTION: A plurality of cooling pipes with the cooling water packed are arranged in the image forming apparatus. A plurality of cooling circulation paths are selectable by manually or automatically selecting the cooling pipes. The plurality of cooling circulation paths include at least a pump 68, a fixation part cooling module 62 and the periphery of a heat discharge part 69. At least one of the plurality of cooling water circulation paths is selected, and a part which should be cooled is cooled. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus, and is particularly suitable for application to an image forming apparatus that employs an electrostatic recording system, an electrophotographic recording system, or the like and has a heating unit.

  First, an intermediate transfer type full-color image forming apparatus as an example of a conventional image forming apparatus will be described. FIG. 8 shows a conventional image forming apparatus.

  As shown in FIG. 8, a plurality of image forming units that obtain a visible image by forming a latent image on a photosensitive drum 111 that is an image carrier using light, magnetism, electric charge, and the like, and visualizing the latent image. 110, a visible image is sequentially transferred from each of these image forming units 110, and an intermediate transfer unit 130 as an intermediate transfer member that forms a multi-color image, and a multi-color image on the intermediate transfer member is transferred to a transfer material. The image forming apparatus includes a transfer unit 136 and a fixing unit 140 for fixing the multi-color image transferred onto the recording material onto the transfer material.

  The intermediate transfer unit 130 uses a belt-like intermediate transfer belt that is stretched around a plurality of rollers and rotates endlessly (or a cylindrical intermediate transfer drum that rotates about a drum axis), and a plurality of the above-described image forming units. The visible image formed on the photosensitive drum 111 in the vicinity of the unit 110 is transferred onto the intermediate transfer unit 130 by the primary transfer charging device 135 disposed at a position facing the image forming unit 110 and the intermediate transfer unit 130. Make primary transfer. The visible images primarily transferred from the plurality of photosensitive drums 111 are superimposed on the intermediate transfer unit 130 and conveyed to a position (secondary transfer position Te) where the intermediate transfer unit 130 is transferred to the transfer material 102 by rotating. The

  The above-described visible image on the intermediate transfer unit 130 is secondary-transferred to the transfer material 102 fed by the paper feed unit 120 as the paper feed unit at the secondary transfer position Te by the transfer unit 136 including a secondary transfer roller. Transcribed. Further, a full-color image is formed by being fixed in the fixing unit 140 described above.

  When obtaining a monochromatic image, the monochromatic visible image is primarily transferred from the specific image forming unit onto the intermediate transfer member, and a monochromatic image is obtained through a process similar to that for forming a full color image.

  In the image forming apparatus having the configuration according to the related art described above, when the main power supply is turned on, the fixing roller itself is heated to about 200 ° C. in order to realize the function of the fixing unit 140. As the temperature of the fixing roller increases, the temperature around the fixing unit 140 also increases.

  Further, when the image forming operation is started and the transfer material is continuously copied or continuously copied, the temperature in the apparatus body rises due to the heat of the fixing device and the transfer material that has passed through the fixing device. Further, from the viewpoint of downsizing the apparatus, the image forming unit is adjacent to the fixing device, and the image forming unit is heated by the radiant heat of the fixing device, and the temperature of the image forming unit further increases.

As described above, when the temperature of the image forming portion rises too much, a so-called blocking phenomenon occurs in which the toner in the portion is slightly melted and then hardened again. When this blocking occurs, the toner adheres to the portion, and appropriate development and proper transfer cannot be performed, so that an appropriate image is not transferred onto the sheet. In particular, when blocking occurs in the cleaning device, it affects both development and transfer.
Greatly affected by blocking.

  Therefore, as a method for preventing the blocking of the image forming unit, a configuration in which a duct 132 through which air passes is conventionally provided between a fixing device as a fixing unit and the image forming unit has been proposed (Patent Document). 1).

The duct 132 is provided with a plurality of holes on the surface with respect to the fixing device, and the ends of the duct 132 are provided with openings at the front and rear of the image forming apparatus, respectively, and are provided in the middle of the duct path. A fan (not shown) allows outside air to pass through the duct 132 and exhausts fixing heat from a hole provided on the surface of the duct 132 facing the fixing device, thereby making it difficult for the heat of the fixing device to be transmitted to the image forming unit. The method is used.
JP 2001-013856 A

  However, in the above-described method, since air is passed through the duct by the fan, a rotating sound of the fan motor, a wind noise generated by the fan wings, and a blowing sound when air flows through the duct are generated. These sounds are very annoying for the user. In recent years, the image forming apparatus tends to be miniaturized, but there is a problem that the heat insulation effect decreases when the duct through which air passes is reduced in the conventional example.

  Therefore, development of a technology for improving the heat insulating effect and the heat radiating effect while suppressing noise in the downsized image forming apparatus has been eagerly desired.

  Accordingly, an object of the present invention is to prevent a temperature rise of the image forming unit by using a water-cooling type cooling unit between the fixing device and the image forming unit without using a fan or a duct, and does not use a fan. Accordingly, an object of the present invention is to provide an image forming apparatus that can achieve noise reduction and can easily realize downsizing of a cooling unit of a cooling device.

  Another object of the present invention is to provide an image forming apparatus that can efficiently cool and reduce energy consumption by selecting a cooling portion of the apparatus according to the situation.

In order to achieve the above object, the present invention provides:
An image forming unit for forming an image;
A transfer portion for transferring a toner image to a transfer material;
A fixing unit for fixing the transferred toner image to the transfer material;
A cooling pipe containing cooling water;
A pump configured to circulate cooling water in the cooling pipe;
A heat dissipating part that reduces the temperature of the cooling water;
An image forming apparatus having a housing,
Multiple cooling water circulation paths can be configured by cooling pipes,
The cooling water circulation path is a path including the pump, the periphery of the fixing unit, and the heat dissipation unit,
An image forming apparatus characterized in that at least one path can be selected from a plurality of cooling water circulation paths.

According to the present invention, the cooling unit of the water cooling system is disposed between the fixing unit and the image forming unit and in the portion to be cooled in the image forming apparatus, so that the inside of the image forming apparatus can be used without using a fan and a duct. Can be prevented, and since no fan is used, the generation of noise can be suppressed and noise reduction can be realized.

  In addition, according to the present invention, the degree of freedom with respect to the shape and arrangement of the cooling pipe is high, and it is possible to easily reduce the size of the cooling device, thereby making it possible to reduce the size of the image forming apparatus. Further, by selecting a cooling point of the apparatus according to the situation, it is possible to efficiently cool and suppress energy consumption. Furthermore, it is also possible to suppress an increase in the number of parts by using an existing thermistor for the temperature information in the apparatus.

  Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. In all the drawings of the following embodiments, the same or corresponding parts are denoted by the same reference numerals. FIG. 1 shows a main part of an image forming apparatus according to the first embodiment of the present invention.

  As shown in FIG. 1, the image output unit is roughly divided into an image forming unit 10, a sheet feeding unit 20, an intermediate transfer unit 30, and a fixing unit in which stations a, b, c, and d having the same configuration are arranged side by side. 40 and a control unit (not shown). Each unit will be described below.

(Image forming part)
First, the image forming unit 10 will be described. In the image forming unit 10, photosensitive drums 11a, 11b, 11c, and 11d as image carriers are pivotally supported at the respective centers, and are configured to be rotationally driven in the arrow direction. Further, the primary chargers 12a, 12b, 12c, 12d, the optical systems 13a, 13b, 13c, 13d, and the developing devices 14a, 14b, 14c, 14d are opposed to the outer peripheral surfaces of the photosensitive drums 11a to 11d in the rotation direction. Has been placed.

  The primary chargers 12a to 12d are configured to be able to supply a uniform charge amount of charge to the surfaces of the photosensitive drums 11a to 11d. When the photosensitive drums 11a to 11d are exposed to light beams such as laser beams modulated according to the recording image signal by the optical systems 13a to 13d and the mirrors 16a, 16b, 16c, and 16d, the surfaces of the photosensitive drums 11a to 11d are exposed. An electrostatic latent image is formed.

  In addition, the electrostatic latent images are visualized by developing devices 14a to 14d that store developers (hereinafter, toners) of four colors of black, magenta, cyan, and yellow, respectively. On the downstream side of the image transfer region (primary transfer regions Ta, Tb, Tc, Td), the visualized visible image is transferred to the intermediate transfer member. The toner remaining on the photosensitive drums 11a to 11d without being transferred to the transfer material is scraped off by the photosensitive drum cleaning devices 15a, 15b, 15c, and 15d. As a result, the surfaces of the photosensitive drums 11a to 11d are cleaned. By the process described above, image formation with each toner is sequentially executed.

(Feeding unit)
Next, the paper feeding unit 20 will be described. The paper feed unit 20 includes cassettes 21a, 21b, and 21c for storing the transfer material 102, and pickup rollers 22a and 22b for feeding out the recording paper stored in the cassettes 21a, 21b, and 21c one by one. The transfer material 102 fed from the pickup rollers 22a and 22b is fed to the registration rollers 25a and 25b, and the transfer material 102 is fed in accordance with the image formation timing of the image forming unit 10. It is composed of registration rollers 25 a and 25 b that are sent to the intermediate transfer unit 30.

Next, the intermediate transfer unit 30 will be described. The intermediate transfer unit 30 is, for example, PE
An intermediate transfer belt 31 made of T (polyethylene terephthalate), PVDF (polyvinylidene fluoride), or the like is wound around a plurality of rollers such as a drive roller 32, a tension roller 33, and a support roller 34. A primary transfer plane A is formed between the two driving rollers 32 and the tension roller 33.

  The drive roller 32 is coated with rubber having a thickness of several millimeters made of urethane or chloroprene on the surface of a metal roller, thereby preventing slippage with the belt. The drive roller 32 is rotationally driven by a pulse motor (not shown).

  The tension roller 33 is configured to apply an appropriate tension to the intermediate transfer belt 31. In the primary transfer regions Ta to Td where the respective photosensitive drums 11a to 11d and the intermediate transfer belt 31 face each other, primary transfer chargers 35a to 35d corresponding to the photosensitive drums 11a to 11d are provided on the back surface side of the intermediate transfer belt 31. 35d is arranged.

  Further, a secondary transfer roller 36 is disposed so as to face the support roller 34 so as to sandwich the intermediate transfer belt 31. A secondary transfer position Te is formed by the nip with the intermediate transfer belt 31. A transfer cleaner 50 for cleaning the image forming surface of the intermediate transfer belt 31 is provided downstream of the secondary transfer portion T.

(Fusing unit)
Next, the fixing unit 40 as a fixing unit will be described. The fixing unit 40 includes a roller pair including a fixing roller 41a having a heat source such as a halogen heater and a pressure roller 41b that presses the fixing roller 41a. A conveyance guide 43 for guiding the transfer material 102 to the nip portion of the roller pair, an inner discharge roller 44 and an outer discharge roller 45 for further guiding the transfer material 102 discharged from the roller pair to the outside of the apparatus. , And a discharge conveyance path roller 49 used when discharging the transfer material 102 to the upper part of the apparatus. Here, the heat source is provided only in the fixing roller 41a, but the heat source may be further provided in the pressure roller 41b. Although not shown, the control unit includes a control board (not shown) for controlling the operation of the mechanism in each unit, a motor drive board (not shown), and the like.

(Device operation)
Next, the operation of the image forming apparatus according to the first embodiment will be described.

  That is, when an image forming operation start signal is supplied, first, the transfer material 102 is sent out one by one from one of the cassettes 21a, 21b, and 21c (including the manual feed cassette) by the pickup roller 22.

  The transfer material 102 is guided between the paper feed guides 24 by the paper feed roller 23 and conveyed to the registration rollers 25a and 25b. At that time, since the registration rollers 25a and 25b are stopped, the leading edge of the paper hits the nip portion.

  Thereafter, the image forming unit 10 starts the rotation of the registration rollers 25a and 25b in accordance with the start timing of image formation. The rotation timing is set so that the toner image primarily transferred onto the intermediate transfer belt 31 by the transfer material 102 and the image forming unit 10 exactly matches the transfer material 102 in the secondary transfer portion T. Has been.

On the other hand, when the image forming operation start signal is issued, the image forming unit 10 causes the toner image formed on the photosensitive drum 11d located on the most upstream side in the rotation direction of the intermediate transfer belt 31 to undergo primary transfer by the above-described process. In the region Td, a primary transfer charger 3 to which a high voltage is applied.
By 5d, primary transfer is performed on the intermediate transfer belt 31. The primarily transferred toner image is conveyed to the next primary transfer region Tc.

  In this case, image formation is performed with a delay by the time during which the toner image is conveyed between the image forming units 10. Then, the next toner image is transferred by aligning the resist on the previous image. Thereafter, the same process is repeated, and finally the four color toner images are primarily transferred onto the intermediate transfer belt 31.

  Thereafter, when the transfer material 102 enters the secondary transfer position Te and is brought into contact with the intermediate transfer belt 31, a high voltage is applied to the secondary transfer roller 36 in accordance with the passing timing of the transfer material 102. Thereafter, the four color toner images formed on the intermediate transfer belt by the above-described process are transferred onto the surface of the transfer material 102.

  Subsequently, the transfer material 102 is accurately guided to the nip portion between the fixing roller 41 a and the pressure roller 41 b by the conveyance guide 43. The toner image is fixed on the paper surface by the heat of the fixing roller 41a and the pressure roller 41b and the pressure at the nip portion. Thereafter, the transfer material 102 is conveyed by the inner paper discharge roller 44, the outer paper discharge roller 45, or the paper discharge vertical path roller 49 and discharged outside the apparatus.

  Next, the cooling means according to the first embodiment will be described with reference to FIGS. FIG. 2 is a perspective view of the image forming apparatus shown in FIG.

  As shown in FIG. 2, cooling modules 62, 63, 64, and 65 are arranged inside the image forming apparatus. That is, the fixing unit cooling module 62 is provided in the vicinity of the fixing unit 40 so as to shield the transfer cleaner 50 and the fixing unit 40. Further, a paper discharge cooling module 63 is provided in the vicinity of the paper discharge conveyance path roller 49. Similarly, a drive unit cooling module 64 is provided in the vicinity of the drive unit 70 of the image forming unit 10 and the intermediate transfer unit 30. Furthermore, an electrical equipment cooling unit 65 is provided in the electrical equipment section 80 that controls the entire apparatus.

  Each cooling module 62-65 is connected by the connection pipe (not shown) for circulating a cooling water. Thereby, a circulation path of the cooling water is configured. Further, a part of the circulation path is connected to the pump 68 and the heat radiating portion 69. The heat dissipating part 69 is exposed on the back surface of the apparatus, and the cooling water heated by circulating through the apparatus is cooled by outside air in the heat dissipating part 69.

  The cooling module 60 is shown in FIG. As shown in FIG. 3, the cooling module 60 is configured such that cooling pipes 60 a are vertically and horizontally provided therein. A cooling pipe port 60b is provided at the end of the cooling pipe 60a. The cooling pipe 60a contains cooling water 60c.

  The cooling pipe port 60b is connected to the other cooling modules 62 to 65, the pump 68, or the heat radiating unit 69 using a connecting pipe (not shown). The cooling module 60 is configured to have an appropriate size according to the unit to be cooled. The diameter of the cooling pipe 60a and the flow rate of the cooling water 60c are appropriately set according to the shape / temperature conditions of the object to be cooled.

  Next, the cooling water circulation path will be described with reference to FIG. FIG. 4 shows circulation paths of the cooling modules 62 to 65, the pump 68, and the heat radiating unit 69 in FIG.

  As shown in FIG. 4, the cooling water circulates in the direction of the arrow. The path is provided with gates 61a to 61e, and the circulation path can be changed by opening and closing these gates. Moreover, the shortest circulation path can be selected by closing the gate 61b. When this shortest circulation path is selected, the cooling water passes through the valve A from the pump 68 and circulates through the fixing unit cooling module 62 and the heat dissipating unit 69 in order.

  Further, by closing the gate 61a and closing arbitrary gates (gates 61c, 61d, 61e), the fixing device and other units can be selected and cooled. At this time, no matter what route is selected, it is configured so that it finally reaches the heat dissipating unit 69 after passing through the periphery of the fixing unit 40 (fixing unit cooling module 62) that has the highest temperature. .

  FIG. 5 shows a circulation path sequence from when the main power source of the image forming apparatus is turned on by the user to when print output is completed and then the power source is turned off.

  As shown in FIG. 5, first, the power of the image forming apparatus is turned on by the user. Then, in the “situation 1” state, the temperature rise to bring the fixing device to about 200 ° C. is started. At this time, the only heat source to be considered in the image forming apparatus is the fixing unit 40. Therefore, the gate 61a is opened and the gate 61b is closed simultaneously with the power-on. Thus, the cooling water is circulated through the minimum circulation path so that the surrounding temperature does not rise due to the fixing heat.

  Next, since the image forming unit 10 prepares for printing, in “situation 2”, driving of the image forming unit is started. At this time, the gate 61a is closed, and the gate 61b and the gate 61c are opened. As a result, the circulation path is changed, and the drive unit 70 that rises with the start of driving is cooled.

  Further, in “Situation 3”, print preparation is completed and print output is started. At this stage, the gate 61e is also opened so that the electrical component is also cooled. Further, when outputting a large number of sheets, the conveyance guide is also heated by the recording paper discharged from the fixing, which affects the apparatus. Therefore, the conveyance guide is cooled by opening the gate 61d as well.

  When the output is finished, in “situation 4”, the operation of the drive unit is finished, and it is in a standby state until the next print output. In this state, since the drive unit / paper discharge unit is not operating, the gates 61c and 61d are closed so that only the fixing device and the electrical system can be cooled.

  As described above, the cooling water circulation path is switched from when the power supply of the image forming apparatus is turned on to when it is turned off.

  As described above, in the first embodiment, the inside of the image forming apparatus can be efficiently cooled by the water cooling type cooling module appropriately disposed inside the image forming apparatus. In particular, by using the pump 68, the fixing unit cooling module 62, and the heat dissipating unit 69 as the shortest path among the cooling water circulation paths, the periphery of the fixing unit 40 that has the highest temperature inside the image forming apparatus can be efficiently cooled. can do.

In addition, unlike the conventional cooling configuration using fans and ducts, the cooling water is liquid, so a water-cooled cooling module can be placed in a minute gap, thus reducing the overall size of the image forming apparatus. It becomes possible to plan. In addition, since no fan is used for cooling, no wind noise is generated due to the operation of the fan, so that significant noise reduction can be achieved in the image forming apparatus. It is also possible to set the cooling water circulation path to be linked with a series of print output operations, so that each part can be cooled very efficiently, and the energy consumption of the power to operate the pump is saved. Can also be achieved.

(Second Embodiment)
Next explained is an image forming apparatus according to the second embodiment of the invention. FIG. 7 shows a cooling path of the image forming apparatus according to the second embodiment. FIG. 7 is a schematic view of the circulation paths of the cooling modules 62 to 65, the pump 68, and the heat dissipating unit 69 shown in FIG. 4, with the features of the second embodiment added.

  That is, in the cooling module according to the second embodiment, a temperature detection sensor 61f is provided. These temperature detection sensors 61f are connected to the cooling control unit 67, respectively. Thereby, the temperature signal around each cooling module detected by the temperature detection sensor is transmitted to the cooling control unit 67. As for the temperature detection around the fixing unit cooling module 62 (around the fixing unit 40), a thermistor 61g normally used for adjusting the temperature of the fixing unit cooling module 62 is used, but a temperature detection sensor 61f is newly provided. It is also possible.

  When the temperature signals output from the respective temperature detection sensors 61f and the thermistor 61g are supplied to the cooling control unit 67, the cooling control unit 67 determines the unit to be cooled based on the supplied temperature signals. Is done. An opening / closing instruction signal is supplied to each of the gates 61a to 61e in order to select a cooling water circulation path.

  According to the second embodiment, each part can be cooled more efficiently by controlling the selection of the cooling circulation path based on the temperature signal output from each cooling module. Furthermore, it is possible to deal with the influence of the external environment and the temperature rise in the event of an abnormality in a timely and appropriate manner. In the image forming apparatus, regarding the temperature detection around the fixing unit 40 where the temperature rises most, the thermistor 61g originally provided as a component of the fixing unit 40 is used to reduce the number of parts and the part cost. be able to.

  As mentioned above, although embodiment of this invention was described concretely, this invention is not limited to the above-mentioned embodiment, The various deformation | transformation based on the technical idea of this invention is possible.

  For example, the unit configuration of the image forming apparatus according to the first embodiment described above is an example for explaining the effectiveness of the present invention, and the size of the image forming apparatus and the selection of the circulation path, the selection of the circulation path, and the cooling timing are as follows. Optimized by operation sequence such as placement.

  Specifically, for example, in a series of print output operations, when the cooling times of the drive unit cooling module 64 and the paper discharge cooling module 63 are substantially synchronized, as shown in FIG. It is also possible to configure the circulation path so that the cooling of the sheet 64 and the paper discharge cooling module 63 is performed simultaneously. In addition, when there is a unit to be cooled other than, for example, a laser scanner, the unit is cooled by adding a path for cooling the unit to the circulation path.

1 is a schematic view of an intermediate transfer type full-color image forming apparatus according to the present invention. 1 is a schematic cross-sectional perspective view of an intermediate transfer type full-color image forming apparatus showing a characteristic part in the present invention. It is a schematic sectional drawing of the cooling module in this invention. It is a schematic diagram of the cooling water circulation path in this invention. It is a schematic diagram at the time of the change of the cooling water circulation path linked with the print output operation | movement of the apparatus in this invention. It is the schematic diagram which showed an example of the cooling water circulation path | route in this invention. It is the schematic diagram of the cooling water circulation path | route which showed 2nd Embodiment in this invention. It is a schematic diagram of a full color image forming apparatus of an intermediate transfer system in a conventional example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image formation part 11a, 11b, 11c, 11d Photosensitive drum 12a, 12b, 12c, 12d Primary charger 13a, 13b, 13c, 13d Optical system 14a, 14b, 14c, 14d Developing device 15a, 15b, 15c, 15d Photosensitive drum Cleaning device 16a, 16b, 16c, 16d Mirror 20 Paper feed unit 21a, 21b, 21c Cassette 22, 22a, 22b Pickup roller 23 Paper feed roller 24 Paper feed guide 25a, 25b Registration roller 30 Intermediate transfer unit 31 Intermediate transfer belt 32 Drive Roller 33 Tension roller 34 Support roller 35a-35d Charger for primary transfer 36 Secondary transfer roller 40 Fixing unit 41a Fixing roller 41b Pressure roller 43 Conveying guide 44 Inner discharge roller 45 Outer discharge roller 49 Paper transport path roller 50 Transfer cleaner 60 Cooling module 60a Cooling pipe 60b Cooling pipe port 60c Cooling water 61a, 61b, 61c, 61d, 61e Gate 62 Fixing unit cooling module 63 Paper discharge cooling module 64 Drive unit cooling module 65 Electrical cooling unit 67 Cooling Control unit 68 Pump 69 Heat radiation unit 70 Drive unit 80 Electrical unit 102 Transfer material

Claims (10)

An image forming unit for forming an image;
A transfer portion for transferring a toner image to a transfer material;
A fixing unit for fixing the transferred toner image to a transfer material;
A cooling pipe containing cooling water;
A pump configured to circulate the cooling water in the cooling pipe;
A heat dissipating part for lowering the temperature of the cooling water;
An image forming apparatus having a housing,
A plurality of cooling water circulation paths can be configured by the cooling pipe,
The cooling water circulation path is a path including the pump, the periphery of the fixing unit, and the heat dissipation unit,
An image forming apparatus characterized in that at least one path can be selected from the plurality of cooling water circulation paths.   The plurality of cooling water circulation paths are paths including at least the pump, the periphery of the fixing unit, and the heat dissipation unit, and the cooling water passes through the periphery of the fixing unit immediately before passing through the heat dissipation unit. The image forming apparatus according to claim 1, wherein the image forming apparatus is configured as follows.   A cooling water circulation path around the fixing unit is disposed above the fixing unit, and is disposed at a position where the fixing unit, the transfer unit, and the image forming unit are blocked. The image forming apparatus according to claim 1.   The image forming apparatus according to claim 1, wherein the heat dissipating part is provided in the vicinity of the fixing part and at a position exposed on a side surface of the housing.   A drive unit for driving the transfer unit, and an electrical unit provided with a control unit for controlling the entire image forming apparatus, wherein the drive unit and the electrical unit are at least one of the plurality of cooling water circulation paths. 5. The cooling unit according to claim 1, wherein the driving unit and the electrical unit are selectively cooled by the cooling water circulation path selected by the cooling water passing through one cooling water circulation path. The image forming apparatus described.   2. The image forming apparatus according to claim 1, wherein switching of the cooling circulation paths among the plurality of cooling water circulation paths is performed at a timing based on an operation sequence of the image forming apparatus itself. .   The image forming apparatus according to claim 1, wherein the cooling water contains an antifreeze and a preservative.   The plurality of cooling water circulation paths are divided for at least one unit, and a temperature detection sensor is provided in the vicinity of the cooling water circulation path divided for each unit, and the temperature output from the temperature detection sensor The image forming apparatus according to claim 1, further comprising a cooling control unit that instructs switching of the cooling water circulation path based on the information.   Based on the temperature information output from the temperature detection sensor, the cooling control unit determines the order in which the cooling water is circulated through the cooling water circulation path corresponding to the plurality of units determined to require cooling among the units. 9. The image forming apparatus according to claim 8, wherein the image forming apparatus is configured to be optimized. Temperature information around the fixing unit is output from a thermistor provided to adjust the temperature of the fixing unit, and the temperature information output from the thermistor is supplied to the cooling control unit. The image forming apparatus according to claim 8.

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