JP5292822B2 - Cooling device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling device having a liquid cooling system, which is properly controlled according to the use of an image forming apparatus and is free from waste and highly efficient, and to provide an image forming apparatus having the same. <P>SOLUTION: A controller controls the cooling abilities of heat exchangers 32A, 32B and 32C to be controlled. That is, the controller performs control so that: when there is any heat exchanger in which a temperature rise is great in heat generating member to be cooled, the heat absorbing action of the heat exchanger is increased; and when the temperature rise of the heat generating member to be cooled is small, the heat absorbing action of the heat exchanger is decreased. Specifically, the controller controls the amount of a circulation liquid supplied to each heat exchanger by a pump 31, quantities of air sent by the cooling fans 34A and 34B of a radiator 33, and supply or non-supply of the circulation liquid to each heat exchanger. Accordingly, the cooling abilities of the heat exchangers 32A, 32B, and 32C are changed according to the operating conditions of the image forming apparatus. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a cooling device that cools a plurality of heat generating members present in an image forming apparatus, and more particularly, to a cooling device that cools using a circulating liquid and an image forming apparatus including the same.

In an image forming apparatus such as a copying machine or a printer, an exposure device that forms an electrostatic latent image on the surface of a photoreceptor, a developing device that supplies toner to the electrostatic latent image to form a toner image, or a toner image Many members and units for generating heat, such as a fixing device, are installed on a transfer material such as transfer paper, and various countermeasures against heat generated from these heat generating members have been studied.
Therefore, it has been proposed to cool the heat generating member using various cooling devices. For example, as described in Patent Document 1, it has been proposed to cool the recording paper after fixing using a heat pipe.
However, the cooling by the heat pipe has a limit in the amount of heat that can be transported, so that it cannot be sufficiently cooled, resulting in a problem that the image quality is impaired. In particular, in recent years, in an image forming apparatus that is required to form a small and high-speed image, a more efficient cooling device is required. In order to satisfy such a requirement, cooling is performed by circulating a liquid such as water. Liquid cooling systems have been developed and proposed. (For example, see Patent Document 2)
JP 2002-62702 A JP 2005-148659 A

In this Patent Document 2, a tank that stores a circulating liquid for cooling a plurality of heat generating members existing in an image forming apparatus, a plurality of pipes branched from the tank, and the pipes connected to the pipes are described. A heat exchanger that cools each heat generating member, a drive source for circulating the circulating liquid, and a second heat exchanger that performs heat exchange for adjusting the temperature of the liquid are provided to efficiently cool the plurality of heat generating members. A cooling device is disclosed. This cooling device can effectively cool a plurality of heat generating members, and is an effective cooling device in a small and high-speed image forming apparatus.
However, since this cooling device does not have a control device for controlling the operation of a heat exchanger or the like that cools each heat generating member connected to each pipe line, the power supply switch of the image forming apparatus is turned on. At the same time, each component of a liquid cooling system in which a driving source such as a pump for circulating the circulating liquid and an air cooling fan for radiating heat with the second heat exchanger is always operated. However, depending on how the image forming apparatus is used, the operation rate of the image forming apparatus is high, such as when the image forming operation is not performed once per hour, or conversely, 500 copies are made continuously. Sometimes it is not always constant. Therefore, naturally, the temperature rise also changes depending on the use situation.

Thus, in the thing of the said patent document 2, since it does not have the control apparatus which controls operation | movement of the heat exchanger etc. which cool each said heat generating member connected to each pipe line, as mentioned above, Since the liquid cooling system is always operated regardless of the use state of the image forming apparatus, excessive cooling is sometimes performed in some cases. This is not an efficient cooling, and is not desirable from the viewpoint of energy saving and fan noise.
The present invention has been made in consideration of the above circumstances, and is provided with a cooling device including a liquid cooling system that is appropriately controlled according to how the image forming apparatus is used and that is wasteful and has a high efficiency. Another object of the present invention is to provide an image forming apparatus.

In order to solve the above-described problem, the invention described in claim 1 includes a plurality of heat exchangers that exchange heat with a plurality of heat generating members present in the image forming apparatus, and a liquid that circulates through the heat exchanger. A pump for feeding and a storage tank for storing the circulating liquid to be circulated, wherein the pump sucks the circulating liquid from the storage tank, and supplies the sucked circulating liquid to the heat exchanger to after the heat-generating member cooling, the circulating liquid is refluxed to the receiving tank, a control device for varying the cooling capacity of the plurality of heat exchangers in accordance with the operation state of the image forming apparatus, wherein the control device, the moment The cooling capacity of the heat exchanger is changed on the basis of the temperature rise due to the previous number of output sheets and the temperature rise due to the current number of output sheets .
According to a second aspect of the present invention, a plurality of heat exchangers that exchange heat with a plurality of heat generating members present in the image forming apparatus, a pump that circulates and supplies liquid to the heat exchangers, and a circulation unit are provided. A storage tank for storing the circulating liquid, wherein the pump sucks the circulating liquid from the storage tank, supplies the sucked circulating liquid to the heat exchanger, cools the heat generating member, and then circulates the circulating liquid. the liquid is refluxed to the receiving tank, in response to said operating state of the image forming apparatus includes a control device for varying the cooling capacity of the plurality of heat exchangers, wherein the control device is a plurality of output instruction continuously In this case, the heat exchanger operating condition corresponding to the temperature rise due to the continuous output number corresponding to the output instruction before the present time is applied regardless of the continuous output number corresponding to the current output instruction .

According to a third aspect of the present invention, a plurality of heat exchangers that exchange heat with a plurality of heat generating members present in the image forming apparatus, a pump that circulates and supplies liquid to the heat exchangers, and a circulation system are provided. A storage tank for storing the circulating liquid, wherein the pump sucks the circulating liquid from the storage tank, supplies the sucked circulating liquid to the heat exchanger, cools the heat generating member, and then circulates the circulating liquid. A control device is provided for returning the liquid to the storage tank and changing the cooling capacity of the plurality of heat exchangers according to the operation status of the image forming device , the control device including an operation time and a continuous output of the image forming device. The cooling capacity of the heat exchanger is changed based on the number of sheets .
According to a fourth aspect of the present invention, there is provided an image forming apparatus including the cooling device according to any one of the first to third aspects.

  According to the present invention, by including the control device that changes the cooling capacity of the plurality of heat exchangers according to the operation status of the image forming apparatus, the image forming apparatus is appropriately controlled according to how the image forming apparatus is used. Thus, it is possible to provide a cooling device including a wasteful and highly efficient liquid cooling system and an image forming apparatus including the same.

  Generally, image forming apparatuses such as copying machines and laser printers are used every day. The temperature change of the image forming apparatus is greatly affected by the usage frequency and usage conditions such as the number of copies (copying) and printing (printing) since the power is turned on that day. As a result, the temperature rise at various locations in the image forming apparatus varies depending on the usage situation. When the frequency of use is very low, the temperature rise in the entire image forming apparatus is also small, so that the amount of circulating liquid and the cooling fan of the heat dissipation device that cools the circulating liquid can be sufficiently cooled without operating at full power. it can. On the other hand, in a situation where hundreds of continuous copies or dozens of sheets are frequently printed, the temperature rise of the image forming apparatus becomes large. As described above, since the temperature rise varies depending on the operation status of the image forming apparatus, it is important for the liquid cooling method to perform various controls in accordance with the operation status and the temperature increase.

Each unit in the image forming apparatus has a different temperature rise timing depending on its function. When the power supply of the image forming apparatus is turned on, the fixing device and the like are heated and held at a predetermined temperature, so that the surroundings are quickly affected by heat and the temperature rises, so cooling is naturally necessary. On the other hand, if the other units are not actually started to form an image, the temperature rises little and cooling is hardly required. However, when the copy button is pressed and the apparatus starts copying, the optical scanner, writing unit, and the like start to operate, so the temperature rises at various points in the machine. As described above, the temperature rise varies depending on the operation status such as the frequency of use of copies, the number of continuous copies, and the standby time. Therefore, the pumps that circulate the circulating liquid in the liquid cooling system at the same time as the power is turned on, and the cooling fan of the heat dissipation device are uniformly useless in the conventional method that starts at the rated value, which is not preferable from the viewpoint of energy saving and noise reduction. Absent.
Therefore, in order to improve the above-described problem, the present invention includes a control device that changes the cooling capacity of the plurality of heat exchangers according to the operation status of the image forming apparatus. Depending on the situation, the cooling capacity of the heat exchanger corresponding to multiple heat generating members in the image forming device can be changed to efficiently operate the cooling device to improve energy saving and noise of the air cooling fan. It is.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing a schematic configuration of a copying machine of an image forming apparatus according to an embodiment of the present invention.
The copying machine according to this embodiment includes a reading optical unit 1 that reads a document by reflecting light, an image forming unit 2 provided below the reading optical unit 1, and a transfer material S such as transfer paper supplied to the image forming unit 2. And a paper unit 3.
The reading optical unit 1 includes a first scanner 4a and a second scanner 4b for irradiating light on a document placed on a glass plate (not shown), and a reflection applied to the document from the first scanner 4a and the second scanner 4b. A lens 11 for imaging light and a CCD (Charge Coupled Device) image sensor 13 for converting reflected light from an original into an electrical signal are provided, and an image of the original is scanned by scanning the first scanner 4a and the second scanner 4b. The image information of the original is read by being converted into an electrical signal by the CCD image sensor 13. Then, an electrical signal of the image information of the original read in this way is sent to the optical writing unit 5 of the image forming unit 2 described later, and an electrostatic latent image is formed on the photosensitive drum 20.

The image forming unit includes an optical writing unit 5 that irradiates a laser beam corresponding to the image information on the photosensitive drum 20 based on an electrical signal of image information of the document fed from the reading optical unit 1, and will be described later. In this way, the photosensitive drum 20 that forms a toner image corresponding to the image information of the document, the intermediate transfer unit 19 that transfers the toner image on the photosensitive drum 20, and the toner image transferred to the intermediate transfer unit 19 are the transfer material S. And a fixing unit 27 for fixing the toner image transferred onto the transfer material S.
The optical writing unit 5 emits laser light emitted in accordance with yellow, cyan, magenta and black color image information from a laser diode (LD) (not shown), a polygon mirror 15, two fθ lenses 12, and a BTL lens. 9 and the writing mirror 7 irradiate the surface of the photosensitive drum 20 in synchronization with the rotation of the photosensitive drum 20 to form an electrostatic latent image on the photosensitive drum 20. Reference numeral 8 denotes a protective glass.

  The photosensitive drum 20 is rotated in the direction of arrow A by a drive motor (not shown), and is uniformly charged by the charging charger 10 attached around the photosensitive drum 20, and the uniformly charged photosensitive drum 20 is The electrostatic latent images corresponding to the respective colors are formed by the laser light based on the image information corresponding to the respective colors from the optical writing unit 5 described above. Thus, the photosensitive drum 20 on which the electrostatic latent images corresponding to the respective colors are formed is supplied with the toner of the color corresponding to the electrostatic latent image from the revolver type developing unit 6 to the electrostatic latent image. The image is converted into a toner image and developed. The toner image thus developed is transferred onto the intermediate transfer belt 19a of the intermediate transfer unit 19. The toner remaining on the photosensitive drum 20 after the toner image is transferred onto the intermediate transfer belt 19a is removed from the surface of the photosensitive drum 20 by the drum cleaning unit 16.

The revolver type developing unit 6 stores toners of yellow, cyan, magenta, and black colors, and developing devices 6aY, 6aC, 6aM, and 6aK that supply the toner to the surface of the photosensitive drum 20 are arranged on the rotating shaft 6b. It is supported rotatably in the direction of arrow B. When an electrostatic latent image of a color corresponding to the image information from the optical writing unit 5 is formed on the photosensitive drum, the developing device 6a for the color is rotated to a position facing the photosensitive drum 20. Then, toner of a corresponding color (corresponding to black 6aK in FIG. 1) is supplied from the developing device to form a toner image.
The intermediate transfer unit 19 is configured to electrically transfer an endless intermediate transfer belt 19a stretched on the roller 14 and rotated and transferred in the direction of arrow C, and a toner image formed on the surface of the photosensitive drum 20 to the intermediate transfer belt 19a. An intermediate transfer charger 23 for transferring the toner image and a transfer material transfer charger 28 for transferring the toner image transferred on the intermediate transfer belt 19a onto the transfer material S are provided. Further, the intermediate transfer unit 19 includes a lubricant application brush 17 that applies a lubricant onto the intermediate transfer belt 19a, and a belt cleaning unit that removes toner remaining after the toner image is transferred onto the transfer material S from the intermediate transfer belt 19a. 25 is provided.
The fixing unit 27 heats and pressurizes the toner image of the transfer material S onto which the toner image is transferred from the intermediate transfer belt 19a conveyed by the endless conveyance belt 26, and fixes and fixes the toner image on the transfer material S. And a pressure roller 27b.

  A procedure for forming an image on the transfer material S by such a copying machine will be described. First, the surface of the rotating photosensitive drum 20 is uniformly charged by the charging charger 10. As described above, the writing unit 5 irradiates laser light corresponding to the color corresponding to the image information on the surface of the photosensitive drum 20 that is uniformly charged in this manner, thereby forming an electrostatic latent image. Subsequently, toner is supplied to the electrostatic latent image formed on the photoconductive drum 20 from a developing device having a color corresponding to the image information to form a toner image. The toner image thus formed is transferred to the intermediate transfer belt 19a by the intermediate transfer charger 23. Similarly, an electrostatic latent image corresponding to another color of the image information is formed on the photosensitive drum 20, and the developing unit 6 is rotated with respect to the electrostatic latent image from the developing devices of other colors. Toner images of other colors are supplied to form toner images of other colors. The toner images of other colors are similarly transferred onto the toner image transferred to the intermediate transfer belt 19a.

Thus, when the toner image of the color corresponding to the last color is transferred onto the intermediate transfer belt 19a, the intermediate transfer belt 19a is rotated and transferred, and the color toner image on the intermediate transfer belt is transferred to the transfer material transfer charger. The sheet is transferred onto the transfer material S fed from the registration roller 21 at the feeding timing 28. Note that the transfer material S is fed one by one to the registration roller 21 via the intermediate roller 22 and is temporarily held by the registration roller. Then, it is fed to the transfer material transfer charger 28 in accordance with the feeding timing.
The color toner image transferred onto the transfer material S in this way is fed to the fixing unit 27 by the conveyance belt 26, and is subjected to heating and pressurizing processes at the fixing unit 27 to form a color toner image on the transfer material S. The paper is fixed and discharged by a paper discharge roller 29.

In an image forming apparatus such as a copying machine, heat is generated along with the operation of each unit or component during image formation as described above, and the image formation conditions vary as the temperature rises due to this heat generation. Quality etc. may be impaired. For example, as the temperature in the developing device rises, toners stored in the developing device are bound to each other so that supply to the photosensitive drum 20 is not performed properly, or the temperature in the fixing unit 27 rises. Therefore, an appropriate fixing process is not performed and an offset is generated. Therefore, in an image forming apparatus such as a copying machine, a cooling device by air cooling, liquid cooling, or the like is provided in order to suppress such a temperature rise in the device.
In the copying machine according to the present embodiment, heat is generated in the reading optical unit 1, the developing unit 6, the optical writing unit 5, the intermediate transfer unit 19, the fixing unit 27, and the like, and the temperature of the apparatus is increased. However, it does not always work at the same time, and only a part of the unit is operating, etc. The degree of temperature rise depends on the operating status of the unit, the number of images to be formed and the operating status of the copying machine such as the image forming time. Varies with time. By controlling the cooling capacity of the heat exchanger that cools the above unit with the control device according to the operation status of such a copier, the cooling device can be operated efficiently to improve energy saving and noise of the air cooling fan, etc. It is possible.

In the copying machine of the present embodiment, a liquid cooling system that uses a liquid such as water and circulates the liquid in the heat exchanger is employed in order to efficiently cool these units and components.
FIG. 2 is a diagram showing a schematic configuration of a liquid cooling system according to an embodiment of the present invention.
In the liquid cooling system 30 of the present embodiment, the circulating fluid reserve tank 35, the auxiliary tanks 36A and 36B, the heat exchangers 32A, 32B and 32C, and the radiator (heat radiating device) 33 are connected by a single main flow path pipe 37. The pump 31 sucks the circulating fluid in the circulating fluid reserve tank 35 from the suction port 31a, discharges it from the discharge port 31b, and circulates the liquid in the direction of arrow D.
The pump 31 has a circulating fluid discharge capacity of about 0.5 to 2 liters per minute, and the discharge flow rate can be changed by controlling the DC input voltage. The circulating coolant from the pump 31 can be supplied to the heat exchangers 32A, 32B, and 32C in the image forming apparatus through the main channel pipe 37.

As shown in FIG. 3, the discharge ports 36bA and 36bB of the auxiliary tanks 36A and 36B have auxiliary tank valves for supplying the replenishing circulating fluid stored in the auxiliary tanks 36A and 36B to the main flow path pipe 37. 36cA and 36cB are attached, and as will be described later, the opening and closing operations of these valves 36cA and 36cB are controlled by the controller 38 to reduce the temperature of the circulating fluid supplied to the heat exchangers 32A, 32B and 32C. The cooling capacity of the exchangers 32A, 32B, and 32C can be changed. Note that 36aA and 36aB are supply ports through which the circulating fluid is supplied to the auxiliary tanks 36A and 36B.
Similarly, the heat exchangers 32A, 32B, and 32C are disposed in the vicinity of the heating members of the respective units such as the developing unit 6, the fixing unit 27, and the optical writing unit 5 of the copying machine, for example. As shown in FIG. 4, the heat exchanger on / off valves 32cA, 32cB, and 32cC for stopping the operation of the heat exchanger on / off valves 32cA, 32cB, and 32cC are cooled by absorbing heat with the circulating liquid. It is attached to the inflow ports 32aA, 32aB, and 32aC. The heat exchanger on / off valves 32cA, 32cB, and 32cC are controlled to be opened and closed by a controller 38, as will be described later.

Further, as shown in FIG. 4, a channel opening / closing valve is provided in the main channel piping 37 between the respective inlets 32aA, 32aB, 32aC and the outlets 32bA, 32bB, 32bC of the heat exchangers 32A, 32B, 32C. 37A, 37B, and 37C are attached, and the cooling operation of the heat exchangers 32A, 32B, and 32C can be controlled by the controller 38 as described later.
As shown in FIG. 5, the radiator 33 is a corrugated fin-type radiator. Circulating fluid flows from the upper left inflow port 33a, flows horizontally through the flat conduit 33c, and flows out from the lower right outlet 33b. To do. There are ten rows of flat ducts 33c, and a fin 33d shaped like a corrugated sheet is attached between them, and the air currents of the two cooling fans 34A and 34B pass through the gaps between the fins 33d as indicated by the arrow E from the back. Cool down the circulating fluid flowing forward. In this example, two 80 mm square axial fans 34A and 34B are provided. And the air volume of this cooling fan is controlled by the controller 38 mentioned later.

  In general, image forming apparatuses such as copying machines and laser printers are used every day. The temperature change of the apparatus is extremely affected by the usage frequency and usage conditions such as the number of copies (copying) and printing (printing) since the power is turned on that day. As a result, the temperature rise in each part of the machine varies depending on the usage conditions. When the frequency of use is extremely low, the temperature rise in the entire machine is small, so that the circulating fluid amount and the cooling fan of the radiator can be sufficiently cooled without operating at full power. On the other hand, in a situation where hundreds of continuous copies or dozens of sheets are frequently printed, the temperature rise becomes large. As described above, since the temperature rise varies depending on the operation status, it is important for the liquid cooling method to perform various controls according to the operation status and the temperature increase.

In addition, each unit in the image forming apparatus has a different temperature rise timing depending on its function. When the apparatus power supply switch is turned on, the fixing unit 27 and the like are heated and held at a predetermined temperature, so that the surroundings are quickly affected by heat and the temperature rises, so cooling is naturally necessary. On the other hand, if the other units are not actually copied, the temperature rise is small and cooling is hardly required. However, when the copy button is pressed and the apparatus starts a copying operation, the reading optical unit 1, the optical writing unit 5, and the like start to operate, and thus the temperature rises at various locations in the image forming apparatus. Such a temperature rise in the machine varies depending on the operating conditions such as the frequency of use of copies, the number of continuous copies, and the standby time. Therefore, the conventional method in which the pump 31 of the liquid cooling system and the cooling fans 34A and 34B of the radiator 33 are uniformly moved at the same time as the power is turned on is useless, and is not preferable from the viewpoint of energy saving and noise reduction. . Therefore, in the present invention, the cooling method of the liquid cooling system is controlled in accordance with the operation status of the image forming apparatus. In other words, when a large number of copies are taken and continuously operated, the liquid cooling system is controlled so that the cooling efficiency is maximized, and when it is hardly operated, the cooling efficiency is lowered. The cooling apparatus includes a liquid cooling controller that performs control.
Note that the heat generating member of the image forming apparatus referred to in the present invention is not only a member that generates heat like the fixing roller 27a of the fixing unit 27, but also the fixing unit 27 that is heated by the heat generated by the fixing roller 27a or a photosensitive member. It also includes a member or a unit that does not generate heat as in the case of the body drum 20, but is heated by a drive motor (not shown) that rotates the photosensitive drum 20. Further, in the present invention, it is not necessary to provide a heat exchanger for all the heat generating members in the image forming apparatus, and heat is applied to at least two heat generating members of the developing device and the fixing unit that have a large influence on image formation. It is sufficient to have an exchanger.

  FIG. 6 is a diagram showing a schematic configuration of a controller (control device) of the cooling device according to the embodiment of the present invention. When there is a heat exchanger in which the cooling capacity of the heat exchangers 32A, 32B, and 32C to be controlled, that is, the temperature of the heat generating member to be cooled is significantly increased, the control device of the present embodiment absorbs heat from the heat exchanger. On the other hand, when the temperature rise of the heat generating member to be cooled is small, the heat absorbing action by the heat exchanger is controlled to be small. In other words, the operation of the image forming apparatus is controlled by controlling the supply amount of the circulating fluid from the pump 31 to the heat exchanger, the blowing amount of the cooling fans 34A and 34B of the radiator 33, and the presence or absence of the supply of the circulating fluid to the heat exchanger. The cooling capacity of the heat exchangers 32A, 32B, and 32C is changed according to the situation.

  Specifically, the controller 38 supplies current or voltage to the channel opening / closing valve operating means 39A, 39B, 39C such as a solenoid for opening / closing the channel opening / closing valves 37A, 37B, 37C attached to the main channel piping 37. Interfaces 381A, 381B, 381C for controlling the electric power of the etc., and interfaces 382 for controlling the electric power to the valve operating means 40A, 40B for auxiliary tanks such as solenoids for opening / closing the replenisher opening / closing valves 36cA, 36cB. . Further, the controller 38 is for cooling fans that drive the cooling fans 34A and 34B of the radiators 33 and the interfaces 385a, 385b, and 385c that control the power supplied to the pump drive motor 41 that changes the discharge amount of the circulating fluid to the pump 31. Interfaces 384A and 384B are provided for controlling the power supplied to the drive motors 42A and 42B. Further, as will be described later, the controller 38 operates the copying machine fed from the control means 43 for controlling the copying machine main body, such as the number of copies, the operation time of the image forming unit 2, the temperature in the copying machine, and the like. Interfaces 383a and 383b for inputting information signals are provided.

Next, a method for controlling the cooling capacity of the heat exchangers 32A, 32B, and 32C using such a controller 38 will be described.
Since the controller 38 is linked to the operation status of the copying machine via the interface, a signal indicating the operation status of the copying machine from the control device 43 of the copying machine is input to the interfaces 383a and 383b. On the basis of the above, the drive motors 41 and 42 of the pump 31 and the cooling fans 34A and 34B, the open / close valves 36cA and 36cB and 39A, 39B and 39C of the auxiliary tanks 36A and 36B and the flow passage pipe 37 are operated to operate the heat exchanger 32A. , 32B and 32C are controlled. For example, if the copier outputs 75 copies 5 minutes before the current time and copies 200 copies now, what is the temperature of the circulating fluid and the temperature of the heating member (cooled member) due to the copy 5 minutes ago? The data on how much the temperature of the circulating fluid and the temperature of the heat generating member (cooled member) will rise when 200 sheets are further copied are experimental data beforehand. These data are obtained and stored in a memory means (not shown) in the controller 38. Based on these data, the controller 38 determines that the temperature rise of the heat generating member is small, and controls the fans 34A and 34B for radiator air cooling to operate at half the rated voltage and to operate with the air volume lowered to half. did.
In another example, if 1500 copies are taken immediately before the current time and then 300 copies are output continuously, the temperature rises rapidly at the immediately preceding 1500 sheets. Since it is stored in the internal memory means, the discharge flow rate of the circulating fluid of the pump 31 and the air flow rate of the cooling fans 34A and 34B of the radiator 33 are operated at the maximum, and even if the output of 300 copies is continuously made before, The liquid cooling system was operated under this condition.

  In another example, the operating voltage of the pump 31 is controlled by the controller 38. The pump 31 can change the flow rate between 0.5 and 2 liters per minute by making the DC input voltage variable, but the operation rate of the copying machine is high. When copying 200 sheets without interruption, the temperature of the heat generating member of the image forming unit 2 gradually increases and continues to increase, and the flow rate of the circulating fluid flowing to the heat exchangers 32A, 32B, 32C of the heat generating member. In order to increase the cooling efficiency, the operating voltage of the pump 31 is rated based on the conditions stored in advance in the memory means of the controller 38 to maximize the flow rate of the circulating fluid and increase the cooling efficiency. On the other hand, when the operation time of the copying machine is short, for example, when the copying machine itself is several times a few minutes and several copies are made, the temperature of the copying machine itself does not rise so much. Judging the situation, the operating voltage of the pump 31 is lowered to about 8V from the data of the memory means in the controller 38, the flow rate is made about 0.5 l / min, and the temperature of the heating member is adjusted so that the temperature of the heat generating member becomes appropriate. The flow rate was changed.

  As another example, the driving speed of the cooling fans 34A and 34B for cooling the radiator 33 from the controller 38 is controlled to vary the wind speed (air volume). As the wind speed increases, the air volume increases. The radiator 33 was provided with two 80 mm square axial fans (34A, 34B). Here, the controller 38 controls the driving voltage of the cooling fan and changes the wind speed while judging the operation status of the copying machine main body. For example, when copying is not performed for a while after the power is turned on, the copying machine main body enters a sleep mode to save energy. In this case, the cooling fans 34A and 34B lower the drive voltage from the rated value and halve the rotational speed. The wind speed on the discharge side of the radiator 33 was lowered to 0.8 m / sec. On the contrary, when 1000 copies are taken continuously, the fan is operated at the rated value to reduce the circulating fluid temperature, and the cooling speed is increased by increasing the wind speed to 3.8 m / sec. Raised.

As another example, there is a heat generating member in which the image forming unit 2 is not operated and the temperature is not increased, such as immediately after turning on the power of the copying machine or in a standby mode or a pause mode. A part of the flow path opening / closing valves 37A, 37B, and 37C of the pipe 37 was closed, and the circulating fluid was allowed to flow through the heat exchangers 32A, 32B, and 32C that required cooling. As shown in the schematic diagram of the flow path switching shown in FIG. 4, since the flow path opening / closing valves 37A, 37B, and 37C are normally closed, the circulating fluid flows through the heat exchangers 32A, 32B, and 32C. The heat generating member is cooled sequentially. However, for example, when the temperature of the heat generating member with the heat exchanger 32B is not raised when the copying machine main body is in the pause mode, the controller 38 closes the heat exchanger on / off valve 32c and opens the flow path valve 37B. It becomes possible to change the flow path of the circulating fluid from the heat exchanger 32A to the direct heat exchange 32C, and to prevent unnecessary cooling.
Furthermore, if it is not necessary to cool the heat exchanger 32C, the 2-1C heat exchanger on / off valve 32cC is closed and the flow path on / off valve 37C is opened, so that only the heat generating member of the heat exchanger 32A is cooled. Will be. In this way, it is possible to increase or decrease the cooling efficiency as necessary by changing the flow path of the circulating fluid.

  Furthermore, as another example, the case where the replenishment circulating fluid in the auxiliary tank is used to change the temperature of the circulating fluid supplied into the heat exchangers 32A, 32B, 32C will be described. The temperature of the circulating fluid rises relatively abruptly, such as when the copying machine output and output frequency are high. In this case, the flow rate of the pump 31 and the cooling fans 34A and 34B of the radiator 33 are controlled to fully operate to lower the liquid temperature. However, according to instructions from the controller 38, the open / close valves 36cA and 36CA of the auxiliary tanks 36A and 36B, The liquid temperature of the circulating fluid supplied to the heat exchangers 32A, 32B, 32C can be effectively lowered by opening 35cB and circulating together using the supplementary circulating fluid in the auxiliary tanks 36A, 36B. It was. 2 and 3, two auxiliary tanks 36A and 36B are provided, but the number is not limited to two and may be one or more.

  As described above, since the cooling device of the present embodiment includes the control device that changes the cooling capacity of the plurality of heat exchangers according to the operating status of the image forming apparatus, the operating / operating status of the image forming apparatus main body It is possible to predict the temperature rise of the heat generating member in the image forming apparatus that changes with time, and to control the liquid cooling system optimally according to it, and optimize the temperature and save energy and reduce noise. Became possible.

1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. It is a schematic diagram which shows schematic structure of the cooling device of one Embodiment by this invention. It is a schematic diagram which shows schematic structure of the flow path of the auxiliary tank of the cooling device of one Embodiment by this invention. It is a schematic diagram which shows schematic structure of the flow path to the heat exchanger of the cooling device of one Embodiment by this invention. It is a perspective view which shows schematic structure of the radiator used with the cooling device of one Embodiment by this invention. It is a schematic diagram which shows schematic structure of the controller used with the cooling device of one Embodiment by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reading optical unit, 2 Image formation unit, 3 Paper feeding unit, 5 Optical writing unit, 6 Developing unit, 6aY, 6aC, 6aM, 6aK Developing device, 10 Charger charger, 16 Drum cleaning unit, 19 Intermediate transfer unit, 20 Photosensitive Body drum, 21 Registration roller, 23 Intermediate transfer charger, 24 Transfer material transfer unit, 26 Conveyor belt, 27 Fixing unit, 27a Fixing roller, 28 Transfer material transfer charger, 30 Liquid cooling system, 31 Pump, 32A, 32B, 32C Heat Exchanger, 32cA, 32cB, 32cC Heat exchanger open / close valve, 33 Radiator, 34A, 34B Cooling fan, 35 Circulating fluid reserve tank, 36A, 36B Auxiliary tank, 36cA, 36cB Replenisher open / close valve, 37 Main channel piping 37A, 37B, 37C Flow path opening / closing valve, 38 Controller, 39A, 39B, 39C Flow path opening / closing valve operating means, 40A, 40B Auxiliary tank opening / closing valve operating means, 41 Pump drive motor, 42A, 42B Cooling fan drive motor, 43 Control device for copier

Claims (4)

A plurality of heat exchangers for exchanging heat with a plurality of heat generating members present in the image forming apparatus;
A pump that circulates and feeds liquid to the heat exchanger;
A storage tank for storing the circulating liquid to be circulated,
The pump sucks the circulating liquid from the storage tank, feeds the sucked circulating liquid to the heat exchanger, cools the heat generating member, and returns the circulating liquid to the storage tank.
A control device that changes the cooling capacity of the plurality of heat exchangers according to the operation status of the image forming apparatus ;
The said control apparatus changes the cooling capacity of the said heat exchanger based on the rising temperature by the output sheet number before the present time, and the rising temperature by the output sheet number at the present time, The cooling apparatus characterized by the above-mentioned . A plurality of heat exchangers for exchanging heat with a plurality of heat generating members present in the image forming apparatus;
A pump that circulates and feeds liquid to the heat exchanger;
A storage tank for storing the circulating liquid to be circulated,
The pump sucks the circulating liquid from the storage tank, feeds the sucked circulating liquid to the heat exchanger, cools the heat generating member, and returns the circulating liquid to the storage tank.
A control device that changes the cooling capacity of the plurality of heat exchangers according to the operation status of the image forming apparatus;
When a plurality of output instructions are continuously issued , the control device corresponds to the current output instruction with respect to the heat exchanger operating condition corresponding to the temperature rise due to the continuous output number corresponding to the output instruction before the present time. A cooling device characterized by being applied regardless of the number of continuous outputs . A plurality of heat exchangers for exchanging heat with a plurality of heat generating members present in the image forming apparatus;
A pump that circulates and feeds liquid to the heat exchanger;
A storage tank for storing the circulating liquid to be circulated,
The pump sucks the circulating liquid from the storage tank, feeds the sucked circulating liquid to the heat exchanger, cools the heat generating member, and returns the circulating liquid to the storage tank.
A control device that changes the cooling capacity of the plurality of heat exchangers according to the operation status of the image forming apparatus;
The control device changes the cooling capacity of the heat exchanger based on the operation time of the image forming apparatus and the number of continuous outputs . An image forming apparatus comprising the cooling device according to claim 1 .

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