Cooling device and image formation apparatus

Abstract

To detect decrease in a level of coolant within a tank and an attachment state of the tank using a simple configuration.SOLUTION: A floating body 66 is housed in a tank 61 along with coolant and has smaller density than that of the coolant. A swing member 67 is supported in a manner of being able to swing and includes a contact portion 671 which displaces upon contact with the tank 61, and a detected portion 672 which moves in conjunction with the displacement of the contact portion 671. A sensor 68 detects the floating body 66 or the detected portion 672 present at a detection position. The tank 61 includes a restriction portion 615 which restricts a movable range of the floating body 66 to a range with the detection position as the lower limit. When the tank 61 is attached to an attachment portion 60, the detected portion 672 displaces from the detection position to a retracted position in conjunction with the displacement of the contact portion 671.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a cooling device and an image forming apparatus in which a tank for storing a cooling liquid is removably attached. [Background technology]

[0002] The devices constituting an image forming apparatus tend to become hotter due to the increased speed of printing processes.

[0003] For example, in an electrophotographic image forming apparatus, the toner contained in a developing device may become hot due to frictional heat generated by the stirring of the toner. When the toner becomes hot, the softened toner may coagulate, which may cause deterioration in image quality.

[0004] In view of this, the image forming apparatus may be provided with a cooling device. For example, it is known that an electrophotographic image forming apparatus is provided with a liquid-cooling type cooling device that cools the developing device (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2011-112707 A Summary of the Invention [Problem to be solved by the invention]

[0006] In a liquid-cooling type cooling device, a pump circulates the coolant through a tank, a heat exchanger, and a heat dissipation unit. The tank, the pump, the heat exchanger, and the heat dissipation unit are connected by a circulation tube.

[0007] The cooling liquid evaporates and leaks slightly from the connections of the equipment, so that the amount of the cooling liquid in the tank gradually decreases as the cooling device is used for a long period of time.

[0008] When the level of the coolant in the tank falls below a normal level, the tank needs replacing.

[0009] Furthermore, if the cooling device is operated without the tank attached, problems such as leakage of the cooling liquid and overheating of the object to be cooled may occur.

[0010] Therefore, the cooling device is required to have a configuration for detecting a drop in the level of the coolant in the tank and the installation status of the tank.

[0011] On the other hand, there is also a demand for reducing costs by simplifying the configuration of the cooling device.

[0012] An object of the present invention is to provide a cooling device and an image forming apparatus that can detect a drop in the level of coolant in a tank and the installation state of the tank with a simple configuration. [Means for solving the problem]

[0013] A cooling device according to one aspect of the present invention includes a tank, a mounting section, a pump, a heat exchange section, a heat dissipation section, a plurality of tubes, a float, a swinging member, and a sensor. The tank stores a cooling liquid. The mounting section is a section to which the tank is removably mounted. The pump circulates the cooling liquid. The heat exchange section exchanges heat between the cooling liquid and a cooling target. The heat dissipation section radiates heat of the cooling liquid. The plurality of tubes connect the tank, the pump, the heat exchange section, and the heat dissipation section, and form a circulation path for the cooling liquid. The float is accommodated in the tank together with the cooling liquid, and has a density smaller than that of the cooling liquid. The swinging member is swingably supported by the mounting section, and has a contact section that is displaced by contact with the tank and a detection section that is linked to the displacement of the contact section. The sensor is provided on the mounting section, and detects the floating body or the detection section that is present at a detection position. The tank has a limiting portion that limits the movable range of the float when the tank is attached to the attachment portion to a range with the detection position as the lower limit. The contact portion is displaced in response to attachment and detachment of the tank to the attachment portion. When the tank is attached to the attachment portion, the detected portion is displaced from the detection position to a retracted position in conjunction with the displacement of the contact portion.

[0014] According to another aspect of the present invention, there is provided an image forming apparatus including a sheet transporting device, a printing device, and the cooling device. The sheet transporting device transports a sheet. The printing device forms an image on the sheet transported by the sheet transporting device. The cooling device cools a part of the printing device. Effect of the Invention

[0015] According to the present invention, it is possible to provide a cooling device and an image forming apparatus that can detect a drop in the level of the coolant in a tank and the installation state of the tank with a simple configuration. [Brief description of the drawings]

[0016] [Figure 1]FIG. 1 is a configuration diagram of an image forming apparatus including a cooling device according to an embodiment. [Diagram 2] FIG. 2 is a block diagram showing the configuration of a control device in the image forming apparatus. [Diagram 3] FIG. 3 is a perspective view of a main part of the cooling device according to the embodiment. [Figure 4] FIG. 4 is a partial end perspective view of a tank and a sensor in the cooling device according to the embodiment. [Diagram 5] FIG. 5 is a first side view of a main part of the cooling device according to the embodiment (before the tank is attached). [Figure 6] FIG. 6 is a second side view of the main part of the cooling device according to the embodiment (with the tank attached). [Figure 7] FIG. 7 is a third side view of the main part of the cooling device according to the embodiment (when the coolant level is below the reference level). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the following embodiment is an example of the present invention, and is not intended to limit the technical scope of the present invention.

[0018] The cooling device 6 according to the embodiment constitutes a part of an image forming apparatus 10 (see FIG. 1).

[0019] [Configuration of image forming apparatus 10] 1, an image forming apparatus 10 includes a sheet conveying device 3, a printing device 4, and a cooling device 6. The sheet conveying device 3 conveys a sheet 9.

[0020] The sheet transport device 3 includes a sheet feeding mechanism 30 and a plurality of transport roller pairs 31. The sheet feeding mechanism 30 sends out the sheet 9 stored in the sheet storage unit 2 to a transport path 300. The transport path 300 is a passage along which the sheet 9 is transported.

[0021] The plurality of transport roller pairs 31 are rotationally driven by a motor (not shown). The plurality of transport roller pairs 31 rotate to transport the sheet 9 along the transport path 300, and further discharge the sheet 9 onto the discharge tray 1x.

[0022] The printing device 4 executes a printing process. The printing process is a process for forming an image on a sheet 9 conveyed by the sheet conveying device 3. The sheet 9 is an image forming medium such as paper or a sheet-like resin member.

[0023] In this embodiment, the printing device 4 performs the printing process by electrophotography. The printing device 4 includes one or more image forming sections 4x, a laser scanning unit 5, a transfer device 44, and a fixing device .

[0024] 1, the image forming apparatus 10 is a tandem color image forming apparatus, and the printing device 4 includes a plurality of image forming units 4x corresponding to a plurality of toner colors.

[0025] Each of the image forming units 4x includes a drum-shaped photoconductor 41, a charging device 42, a developing device 43, and a drum cleaning device 45. That is, the printing device 4 includes a plurality of photoconductors 41, a plurality of developing devices 43, and a plurality of drum cleaning devices 45 corresponding to a plurality of toner colors.

[0026] In each of the image forming units 4x, a photoconductor 41 rotates, and a charging device 42 charges the surface of the photoconductor 41. A laser scanning unit 5 scans the surface of each of the charged photoconductors 41 with a plurality of laser beams. As a result, an electrostatic latent image is formed on the surface of each of the photoconductors 41.

[0027] Each developing device 43 develops the electrostatic latent image into a toner image by supplying toner to the surface of each photoconductor 41. The toner is a granular developer. The photoconductor 41 is an example of an image carrier that rotates while carrying the toner image.

[0028] In this embodiment, the printing device 4 includes four image forming units 4x corresponding to the toners of the four developing colors, namely, yellow, cyan, magenta, and black, and therefore includes four photoconductors 41, four developing devices 43, and four drum cleaning devices 45.

[0029] The four toner images are formed on the surfaces of the four photoconductors 41. The transfer device 44 transfers the four toner images from the four photoconductors 41 to a sheet 9.

[0030] The transfer device 44 includes an intermediate transfer belt 441, four primary transfer devices 442 corresponding to the four image forming units 4x, a secondary transfer device 443, and a belt cleaning device 444.

[0031] The four primary transfer devices 442 transfer the toner images on the surfaces of the four photoconductors 41 onto the surface of the intermediate transfer belt 441. As a result, a color toner image in which the toner images on the four photoconductors 41 are combined is formed on the surface of the intermediate transfer belt 441.

[0032] The secondary transfer device 443 transfers the color toner image formed on the intermediate transfer belt 441 onto the sheet 9 at a transfer position on the conveying path 300 .

[0033] The fixing device 46 applies heat and pressure to the color toner image transferred to the sheet 9. In this way, the fixing device 46 fixes the color toner image to the sheet 9.

[0034] Each drum cleaning device 45 removes waste toner remaining on the surface of each photoconductor 41. The belt cleaning device 444 removes the waste toner remaining on the intermediate transfer belt 441.

[0035] The cooling device 6 includes a mounting portion 60 , a tank 61 , a pump 62 , one or more heat exchange portions 63 , a heat dissipation portion 64 and a plurality of tubes 65 .

[0036] The tank 61 stores the cooling liquid 6x. That is, the cooling device 6 is a liquid-cooling type device. The mounting part 60 is a part to which the tank 61 is removably mounted.

[0037] A plurality of tubes 65 connect the tank 61, the pump 62, the heat exchanger 63, and the heat dissipator 64, forming a circulation path for the coolant 6x.

[0038] The pump 62 circulates the cooling liquid 6x in the circulation path. The heat exchange unit 63 exchanges heat between the cooling liquid 6x and the object to be cooled. In this way, the heat exchange unit 63 cools the object to be cooled, which has a higher temperature than the cooling liquid 6x. The object to be cooled is a part of the printing device 4.

[0039] In this embodiment, the cooling device 6 includes four heat exchange units 63, and the objects to be cooled are the four developing devices 43. That is, the cooling device 6 cools each of the developing devices 43. The cooling device 6 suppresses a rise in toner temperature in each of the developing devices 43, which is caused by frictional heat generated by the stirring of the toner.

[0040] The heat dissipation section 64 dissipates heat from the coolant 6x whose temperature has increased due to heat exchange with the four developing devices 43. In the example shown in Fig. 1, the heat dissipation section 64 is an air-cooling device having a cooling fan.

[0041] The image forming apparatus 10 further includes an operation device 801 , a display device 802 , and a control device 8 .

[0042] The operation device 801 is a device that accepts operations by a person. For example, the operation device 801 includes one or both of a touch panel and operation buttons.

[0043] The display device 802 is capable of displaying various types of information. For example, the display device 802 is a panel display device such as a liquid crystal display device. The control device 8 controls various types of electric devices included in the image forming apparatus .

[0044] As shown in FIG. 2, the control device 8 includes a central processing unit (CPU) 80, a random access memory (RAM) 81, a secondary storage device 82, a signal interface 83, a communication device 84, and the like.

[0045] The CPU 80 executes various control operations and data processing by executing computer programs. The RAM 81 is a volatile storage device. The RAM 81 temporarily stores the computer programs executed by the CPU 80 and various data.

[0046] The secondary storage device 82 is a computer-readable non-volatile storage device. The secondary storage device 82 stores the computer programs executed by the CPU 80 and various data. For example, one or both of a flash memory and a hard disk drive are adopted as the secondary storage device 82.

[0047] The signal interface 83 converts the detection signals of the various sensors into digital detection data. The detection data is transmitted to the CPU 80.

[0048] The communication device 84 communicates with a plurality of external devices including one or more host devices through a network. The CPU 80 communicates with each of the external devices through the communication device 84. The host device is an information processing device that requests the image forming apparatus 10 to perform the print process.

[0049] The CPU 80 includes a plurality of processing modules that are realized by executing the computer programs, including a main control unit 8a, a print control unit 8b, and a determination unit 8c (see FIG. 2).

[0050] The main control unit 8a executes a process of receiving various requests and a control of making other modules execute processes according to the requests. For example, the main control unit 8a receives a print request through the operation device 801 or the communication device 84. Furthermore, the main control unit 8a causes the print control unit 8b to execute a process according to the print request.

[0051] The print control unit 8b controls the sheet transporting device 3 and the printing device 4. The print control unit 8b causes the sheet transporting device 3 to transport the sheet 9, while causing the printing device 4 to execute the print process.

[0052] The determination unit 8c determines various states of the image forming apparatus 10 according to the detection states of various sensors in the image forming apparatus 10 and the operating states of various devices.

[0053] In the liquid-cooling type cooling device 6, the pump 62 circulates the cooling liquid 6x through the tank 61, the heat exchanger 63, and the heat dissipation unit 64. The tank 61, the pump 62, the heat exchanger 63, and the heat dissipation unit 64 are connected by a plurality of tubes 65.

[0054] The cooling liquid 6x evaporates and leaks slightly from the connections of the devices, so that the amount of the cooling liquid 6x in the tank 61 gradually decreases as the cooling device 6 is used for a long period of time.

[0055] When the level of coolant 6x in tank 61 falls below a normal level, tank 61 needs to be replaced.

[0056] Furthermore, if the cooling device 6 is operated with the tank 61 not attached to the attachment portion 60, inconveniences such as leakage of the cooling liquid 6x and an increase in temperature of the object to be cooled may occur.

[0057] Therefore, the cooling device 6 is required to have a configuration for detecting a drop in the level of the cooling liquid 6x in the tank 61 and the installation state of the tank 61.

[0058] On the other hand, there is also a demand for reducing costs by simplifying the configuration of the cooling device 6.

[0059] The cooling device 6 realizes a device capable of detecting a drop in the level of the cooling liquid 6x in the tank 61 and the installation state of the tank 61 with a simple configuration.

[0060] [Cooling device 6 configuration] The cooling device 6 further includes a swinging member 67 and a sensor 68 shown in FIG. 3, and a floating body 66 shown in FIG.

[0061] The floating body 66 is accommodated in the tank 61 together with the cooling liquid 6x. The floating body 66 has a lower density than the cooling liquid 6x. Therefore, the floating body 66 floats on the surface of the cooling liquid 6x unless its movable range is restricted.

[0062] The tank 61 has lateral limiting portions 614 and a lower limiting portion 615 that limit the movement range of the float 66 (see FIG. 4).

[0063] The lateral limiting portion 614 limits the horizontal movement of the floating body 66. The lateral limiting portion 614 also serves as a guide portion that guides the floating body 66 in the up and down directions.

[0064] When the tank 61 is attached to the attachment part 60, the lower limiting part 615 limits the vertical movement range of the float 66 to a range whose lower limit is the detection position P1. When the level of the cooling liquid 6x in the tank 61 is higher than the detection position P1, the vertical position of the float 66 represents the level of the cooling liquid 6x in the tank 61.

[0065] The swinging member 67 is swingably supported by the mounting portion 60. The swinging member 67 has a shaft portion 670, a contact portion 671, and a detected portion 672. The shaft portion 670 is rotatably supported by the mounting portion 60.

[0066] The contact portion 671 is formed to extend from the shaft portion 670 along the diameter direction of the shaft portion 670. The contact portion 671 is rotatable about the shaft portion 670. The contact portion 671 is displaced in response to the attachment and detachment of the tank 61 to the mounting portion 60.

[0067] When the tank 61 is attached to the attachment portion 60, the contact portion 671 comes into contact with a part of the tank 61 and is displaced from the first position to the second position (see FIGS. 5 and 6).

[0068] FIG. 5 shows the contact portion 671 in the first position, and FIG. 6 shows the contact portion 671 in the second position.

[0069] When the tank 61 is removed from the mounting portion 60, the contact portion 671 is displaced from the second position to the first position by the weight of the swinging member 67 (see FIG. 5).

[0070] When the tank 61 is not attached to the attachment portion 60, the locking portion 6y locks a part of the swinging member 67, so that the contact portion 671 is held in the first position (see FIG. 5).

[0071] The detected portion 672 is formed to extend from the shaft portion 670 along the diameter direction of the shaft portion 670. The detected portion 672 is rotatable around the shaft portion 670.

[0072] The detected portion 672 is displaced between the detection position P1 and the retracted position in conjunction with the displacement of the contact portion 671. Figures 3 and 5 show a state in which the detected portion 672 is at the detection position P1, and Figures 6 and 7 show a state in which the detected portion 672 is at the retracted position.

[0073] When the contact portion 671 is displaced from the first position to the second position, the detected portion 672 is displaced from the detection position P1 to the retracted position (see FIGS. 5 and 6).

[0074] That is, when the tank 61 is attached to the attachment portion 60, the detected portion 672 is displaced from the detection position P1 to the retracted position in conjunction with the displacement of the contact portion 671.

[0075] On the other hand, when the contact portion 671 is displaced from the second position to the first position, the detected portion 672 is displaced from the retracted position to the detection position P1 (see FIG. 5).

[0076] That is, when the tank 61 is removed from the mounting portion 60, the detected portion 672 is displaced from the retracted position to the detection position P1.

[0077] When the tank 61 is not attached to the attachment portion 60, the locking portion 6y locks a part of the swinging member 67, so that the detected portion 672 is held at the detection position P1 (see FIG. 5).

[0078] The sensor 68 is provided on the mounting part 60. The sensor 68 detects the floating body 66 or the detection target part 672 present at the detection position P1.

[0079] In this embodiment, the sensor 68 is an optical sensor having a light-emitting portion 681 and a light-receiving portion 682 (see FIGS. 3 and 4). The light-emitting portion 681 emits detection light toward a detection position P1. The light-receiving portion 682 receives the detection light that has passed through the detection position P1 or the detection light that has been reflected at the detection position P1.

[0080] At least a portion of the tank 61 facing the light emitting portion 681 is made of a transparent material that transmits the detection light. The cooling liquid 6x also transmits the detection light.

[0081] In this embodiment, the sensor 68 is a transmissive optical sensor. Therefore, the light emitting portion 681 and the light receiving portion 682 are disposed opposite to each other across the detection position P1. The light receiving portion 682 receives the detection light that has passed through the detection position P1.

[0082] When the float 66 or the detected part 672 is present at the detection position P1, the detection light is blocked by the float 66 or the detected part 672. In this case, the amount of light received by the light receiving part 682 is small.

[0083] On the other hand, when both the floating body 66 and the detected part 672 are located at positions away from the detection position P1, the detection light passes through the detection position P1 and enters the light receiving part 682. In this case, the amount of light received by the light receiving part 682 is large.

[0084] The light receiving section 682 includes a photoelectric conversion element and outputs to the control device 8 a detection signal that indicates the amount of the detection light received.

[0085] The tank 61 has a pair of recesses 612 (see FIGS. 3 and 4) formed in the outer surface of the tank 61. The pair of recesses 612 includes a first recess 612a and a second recess 612b.

[0086] When the tank 61 is attached to the attachment portion 60, the light-emitting portion 681 of the sensor 68 is inserted into the first recess 612a, and the light-receiving portion 682 of the sensor 68 is inserted into the second recess 612b (see FIG. 4).

[0087] A float receiving portion 613 extending in the vertical direction is formed between the pair of recesses 612 in the tank 61. The float 66 is movable within the float receiving portion 613 according to the level of the cooling liquid 6x.

[0088] When the tank 61 is attached to the attachment part 60, a part of the float housing part 613 is disposed at the detection position P1 (see FIG. 4).

[0089] In this embodiment, when the level of the cooling liquid 6x in the tank 61 is within the allowable range, the float 66 floats on the surface of the cooling liquid 6x at a position higher than the detection position P1 (see FIG. 6). In this case, the sensor 68 does not detect either the detection target 672 or the float 66.

[0090] On the other hand, when the level of the cooling liquid 6x in the tank 61 is below the allowable range, the float 66 is held at the detection position P1 by the lower limiting portion 615 (see FIGS. 4 and 7). In this case, the sensor 68 detects the float 66.

[0091] The determination unit 8c determines whether the tank 61 is in a normal state or an abnormal state based on a detection signal from the sensor 68. In this embodiment, the determination unit 8c that determines the state of the tank 61 configures a part of the cooling device 6. The CPU 81 is an example of a processor that determines the state of the tank 61.

[0092] The normal state is a state in which the tank 61 is attached to the attachment portion 60 and the level of the coolant 6x in the tank 61 is within the allowable range (see FIG. 6). On the other hand, the abnormal state is a state in which the tank 61 is not attached to the attachment portion 60 or a state in which the level of the coolant 6x in the tank 61 is below the allowable range (see FIGS. 5 and 7).

[0093] The determination unit 8c determines that the tank 61 is in the abnormal state when the detection signal from the sensor 68 indicates a state in which an object is present at the detection position P1. On the other hand, the determination unit 8c determines that the tank 61 is in the normal state when the detection signal from the sensor 68 indicates a state in which an object is not present at the detection position P1.

[0094] In this embodiment, when the detection signal of the sensor 68 indicates a state in which the amount of light received by the light-receiving unit 682 exceeds the reference amount, the judgment unit 8c judges that the tank 61 is in the normal state. On the other hand, when the detection signal of the sensor 68 indicates a state in which the amount of light received by the light-receiving unit 682 is below the reference amount, the judgment unit 8c judges that the tank 61 is in the abnormal state.

[0095] When it is determined that the tank 61 is in the abnormal state, the determination unit 8c notifies the user of the abnormal state through the display device 802.

[0096] Furthermore, the print control unit 8b may limit the execution of the print process when it is determined that the tank 61 is in the abnormal state.

[0097] For example, the print control unit 8b prohibits the execution of the print process when it is determined that the tank 61 is in the abnormal state. Also, the print control unit 8b may limit the number of sheets to be continuously printed when it is determined that the tank 61 is in the abnormal state.

[0098] By employing the cooling device 6, it is possible to detect a drop in the level of the cooling liquid 6x and a state in which the tank 61 is not installed with a single sensor 68.

[0099] [First application example] In the cooling device 6, a magnetic sensor may be used as the sensor 68. In this case, the detection target 671 and the floating body 66 include a magnetic material. Alternatively, an ultrasonic sensor may be used as the sensor 68.

[0100] [Second application example] The object to be cooled by the cooling device 6 may be a device other than the developing device 43 in the image forming apparatus 10. For example, the cooling device 6 may cool the fixing device 46.

[0101] [Third application example] The cooling device 6 may be applied to an inkjet type image forming apparatus. For example, the cooling device 6 may cool an inkjet head.

[0102] [Notes on the invention] The following will provide an overview of the invention extracted from the above-described embodiment. Note that the configurations and processing functions described in the following supplementary notes can be selected and combined as desired.

[0103] <Appendix 1> A tank for storing a coolant; a mounting portion to which the tank is removably mounted; A pump for circulating the cooling liquid; a heat exchange unit that exchanges heat between the cooling liquid and an object to be cooled; a heat dissipation portion that radiates heat of the cooling liquid; a plurality of tubes that connect the tank, the pump, the heat exchanger, and the heat dissipator to form a circulation path for the cooling liquid; a float housed in the tank together with the cooling liquid and having a density smaller than that of the cooling liquid; a swingable member supported by the mounting portion so as to be swingable, the swingable member having a contact portion which is displaced by contact with the tank and a detection portion which is interlocked with the displacement of the contact portion; a sensor provided on the mounting part for detecting the floating body or the detection target part present at a detection position; the tank has a limiting section that limits a movable range of the float when the tank is attached to the attachment section to a range having the detection position as a lower limit, the contact portion is displaced in response to attachment / detachment of the tank to / from the mounting portion, A cooling device, wherein when the tank is attached to the attachment portion, the detected portion is displaced from the detection position to a retracted position in conjunction with the displacement of the contact portion.

[0104] <Appendix 2> The cooling device described in Appendix 1, further comprising a processor that distinguishes between a normal state in which the tank is attached to the mounting portion and the level of the cooling liquid in the tank is within an acceptable range, and an abnormal state in which the tank is not attached to the mounting portion or the level of the cooling liquid in the tank is below the acceptable range, based on the detection signal of the sensor.

[0105] <Appendix 3> The cooling device according to claim 1 or 2, wherein the sensor is an optical sensor having a light-emitting unit that emits detection light toward the detection position and a light-receiving unit that receives the detection light that has passed through the detection position or the detection light that has been reflected at the detection position.

[0106] <Appendix 4> The tank is a first recess formed in an outer surface and into which the light emitting unit is inserted; The cooling device described in Appendix 3, further comprising a second recess formed in an outer surface and into which the light receiving portion is inserted.

[0107] <Appendix 5> a sheet conveying device that conveys a sheet; a printing device for forming an image on the sheet conveyed by the sheet conveying device; 5. An image forming apparatus comprising: a cooling device according to any one of claims 1 to 4, which cools a part of the printing device.

[0108] <Appendix 6> The printing device a photoreceptor on whose surface an electrostatic latent image is formed; a developing device that develops the electrostatic latent image into a toner image by supplying toner to a surface of the photoconductor; a transfer device that transfers the toner image from the surface of the photoreceptor to a sheet, The image forming apparatus according to claim 5, wherein the cooling device cools the developing device. [Explanation of symbols]

[0109] 3: Sheet transport device 4: Printing device 6: Cooling device 6x :coolant 6y: Locking part 8: Control device 43: Developing device 61: Tank 62: Pump 63:Heat exchange section 64: Heat dissipation part 65: Tube 66: Floating body 67: Swinging member 68: Sensor 612a: First recess 612b: Second recess 613: Floating body accommodation section 614: Lateral limiting section 615: Lower limit 670: Shaft 671: Contact part 672: Detected part 681: Light emitting part 682: Light receiving section P1: Detection position

Claims

1. A tank for storing a coolant; a mounting portion to which the tank is removably mounted; A pump for circulating the cooling liquid; a heat exchange unit that exchanges heat between the cooling liquid and an object to be cooled; a heat dissipation portion that radiates heat of the cooling liquid; a plurality of tubes that connect the tank, the pump, the heat exchanger, and the heat dissipator to form a circulation path for the cooling liquid; a float housed in the tank together with the cooling liquid and having a density smaller than that of the cooling liquid; a swingable member supported by the mounting portion so as to be swingable, the swingable member having a contact portion which is displaced by contact with the tank and a detection portion which is interlocked with the displacement of the contact portion; a sensor provided on the mounting part for detecting the floating body or the detection target part present at a detection position; the tank has a limiting section that limits a movable range of the float when the tank is attached to the attachment section to a range having the detection position as a lower limit, the contact portion is displaced in response to attachment / detachment of the tank to / from the mounting portion, A cooling device, wherein when the tank is attached to the attachment portion, the detected portion is displaced from the detection position to a retracted position in conjunction with the displacement of the contact portion.

2. 2. The cooling device of claim 1, further comprising a processor that distinguishes between a normal state in which the tank is attached to the mounting portion and the level of the cooling liquid in the tank is within an acceptable range, and an abnormal state in which the tank is not attached to the mounting portion or the level of the cooling liquid in the tank is below the acceptable range, based on the detection signal of the sensor.

3. 3. The cooling device according to claim 1, wherein the sensor is an optical sensor having an emitter that emits detection light toward the detection position, and a light receiver that receives the detection light that has passed through the detection position or the detection light that has been reflected at the detection position.

4. The tank is a first recess formed in an outer surface thereof and into which the light emitting unit is inserted; The cooling device according to claim 3 , further comprising: a second recess formed in an outer surface thereof and into which the light receiving portion is inserted.

5. a sheet conveying device that conveys a sheet; a printing device for forming an image on the sheet conveyed by the sheet conveying device; 3. An image forming apparatus comprising: the cooling device according to claim 1 or 2, which cools a part of the printing device.

6. The printing device a photoreceptor on whose surface an electrostatic latent image is formed; a developing device that develops the electrostatic latent image into a toner image by supplying toner to a surface of the photoconductor; a transfer device that transfers the toner image from the surface of the photoreceptor to a sheet, The image forming apparatus according to claim 5 , wherein the cooling device cools the developing device.

Images