Image forming apparatus

Abstract

Ensure the developing apparatus is properly cooled. [Solution] The image forming apparatus comprises a developing apparatus for developing an electrostatic latent image into a toner image, and a cooling unit for cooling the developing apparatus with a cooling liquid. The cooling unit comprises a cooling pipe made of a metal tube, the internal space of which the pipe has as a flow path for the cooling liquid, and a heat dissipation member disposed between the cooling pipe and the developing apparatus, in contact with the cooling pipe and the developing apparatus, and conducting heat between the cooling pipe and the developing apparatus. The portion of the heat dissipation member that contacts the cooling pipe is elastically deformable.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus.

Background Art

[0002] An image forming apparatus includes a developing device that develops an electrostatic latent image into a toner image. Further, the image forming apparatus includes a cooling unit that cools the developing device. The cooling unit has a circulation tube through which a coolant circulates. Heat conduction occurs between the developing device and the circulation tube, thereby cooling the developing device. Such an image forming apparatus is disclosed in, for example, Patent Document 1.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Depending on the shape of the circulation tube, heat conduction between the developing device and the circulation tube may not be performed well. In this case, the cooling of the developing device becomes insufficient.

[0005] The present invention has been made to solve the above problems, and an object thereof is to provide an image forming apparatus capable of cooling a developing device well.

Means for Solving the Problems

[0006] An image forming apparatus according to one aspect of the present invention comprises a developing apparatus for developing an electrostatic latent image into a toner image, and a cooling unit for cooling the developing apparatus with a cooling liquid. The cooling unit comprises a cooling pipe made of a metal tube, the internal space of which the pipe has a flow path for the cooling liquid, and a heat dissipation member disposed between the cooling pipe and the developing apparatus, in contact with the cooling pipe and the developing apparatus, and conducting heat between the cooling pipe and the developing apparatus. The portion of the heat dissipation member that is in contact with the cooling pipe is elastically deformable. [Effects of the Invention]

[0007] The configuration of the present invention allows for effective cooling of the developing apparatus. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of an image forming apparatus according to an embodiment. [Figure 2] This is a schematic diagram of the image forming unit and its surrounding area according to an embodiment. [Figure 3] This is a perspective view of a developing apparatus according to an embodiment. [Figure 4] This is a schematic cross-sectional view of a developing apparatus according to an embodiment. [Figure 5] This is a perspective view of a developing apparatus and cooling unit according to an embodiment. [Figure 6] This is a schematic cross-sectional view of a cooling unit according to an embodiment. [Figure 7] This is a schematic diagram showing the flow path of the cooling unit according to the embodiment. [Figure 8] This is a perspective view of a cooling tube according to an embodiment. [Figure 9] This is a side view of the cooling pipe connection and its surrounding area according to an embodiment. [Figure 10] This is a perspective view of a heat dissipation member according to an embodiment. [Modes for carrying out the invention]

[0009] The image forming apparatus 100 of this embodiment will be described below with reference to Figures 1 to 10, using a tandem-type color laser printer as an example. Note that the present invention is not limited to color laser printers, but is also applicable to monochrome printers and multifunction devices.

[0010] For ease of understanding, the diagrams referenced in the following explanation show the XYZ Cartesian coordinate system. The Z direction is the vertical direction and corresponds to the up and down direction of the image forming apparatus 100. The flat surface on which the image forming apparatus 100 is installed is perpendicular to the Z direction. The direction of the arrow on the Z axis is up, and the opposite direction is down.

[0011] The X direction is one horizontal direction, and the Y direction is the other horizontal direction. For example, the X direction corresponds to the front-to-back direction of the image forming apparatus 100. The Y direction corresponds to the left-to-right direction of the image forming apparatus 100.

[0012] <Overall configuration of the image forming apparatus> As shown in Figure 1, the image forming apparatus 100 of this embodiment includes a main transport path MP. The image forming apparatus 100 also includes a sheet cassette CA. The sheet cassette CA is detachable from the main body of the image forming apparatus 100. The sheet cassette CA contains the sheets S used in the printing job. The sheets S are supplied from the sheet cassette CA to the main transport path MP. The main transport path MP passes through the sheet supply position P0, the transfer position P1 and the fixing position P2 in that order, and then reaches the discharge tray ET.

[0013] In a print job, a sheet S from the sheet cassette CA is supplied from the supply position P0 to the main transport path MP. The image forming apparatus 100 transports the sheet S along the main transport path MP. The image forming apparatus 100 then prints an image on the sheet S as it is being transported. In other words, the image forming apparatus 100 transfers a toner image onto the sheet S as it is being transported. At the transfer position P1, the toner image transfer process is performed onto the sheet S as it is being transported. At the fixing position P2, the toner image is fixed onto the sheet S.

[0014] The image forming apparatus 100 includes image forming units 10 for four colors: cyan, magenta, yellow, and black. Each image forming unit 10 forms a toner image of the corresponding color. Hereinafter, the configuration of one of the image forming units 10 will be described while focusing on it. The basic configurations of each image forming unit 10 are the same as each other. Therefore, the description of the configurations of the other image forming units 10 will be omitted by referring to the following description.

[0015] As shown in FIG. 2, the image forming unit 10 includes a developing device 1. The image forming unit 10 also includes a photosensitive drum 101, a charging device 102, an exposure device 103, and a cleaning device 104.

[0016] When the image forming unit 10 forms a toner image, the photosensitive drum 101 rotates. The charging device 102 charges the outer peripheral surface of the photosensitive drum 101. The exposure device 103 exposes the outer peripheral surface of the photosensitive drum 101 to form an electrostatic latent image on the outer peripheral surface of the photosensitive drum 101. Then, the developing device 1 supplies toner to the electrostatic latent image on the outer peripheral surface of the photosensitive drum 101 and develops the electrostatic latent image into a toner image. The cleaning device 104 removes the residual toner on the outer peripheral surface of the photosensitive drum 101.

[0017] Here, the image forming apparatus 100 includes a cooling unit 2. The cooling unit 2 cools the developing device 1 with a coolant. The cooling unit 2 will be described in detail later.

[0018] Returning to FIG. 1, the image forming apparatus 100 includes an intermediate transfer belt 105. The intermediate transfer belt 105 is an endless belt. The intermediate transfer belt 105 contacts the outer peripheral surface of the photosensitive drum 101 and is driven (rotated) in the direction indicated by the arrow D in FIG. 1 in that state.

[0019] The image forming apparatus 100 is equipped with a plurality of primary transfer rollers 106. One primary transfer roller 106 is assigned to each of the cyan, magenta, yellow, and black colors. Each primary transfer roller 106 is positioned on the inner circumference side of the intermediate transfer belt 105. Each primary transfer roller 106 is positioned opposite the photoreceptor drum 101 that carries the toner image of the corresponding color, with the intermediate transfer belt 105 in between.

[0020] The image forming apparatus 100 is equipped with one secondary transfer roller 107. The secondary transfer roller 107 presses against the outer surface of the intermediate transfer belt 105 at the transfer position P1. The secondary transfer roller 107 forms a transfer nip between itself and the intermediate transfer belt 105. The main transport path MP passes through the transfer nip.

[0021] In a print job, the sheet S is transported toward the transfer position P1 (i.e., the transfer nip). The sheet S passes through the transfer nip while being transported.

[0022] The intermediate transfer belt 105 receives the primary transfer of toner images from each photoreceptor drum 101. The intermediate transfer belt 105 rotates with the toner images supported on its outer surface. As the sheet S passes through the transfer nip, the sheet S comes into contact with the outer surface of the intermediate transfer belt 105. This results in a secondary transfer of the toner image to the sheet S as it passes through the transfer nip.

[0023] Furthermore, various rotating parts of the image forming unit 10, such as the photosensitive drum 101, rotate around an axis extending in the X direction. Similarly, the primary transfer roller 106 and the secondary transfer roller 107 also rotate around an axis extending in the X direction.

[0024] The image forming apparatus 100 includes a fixing unit 108. The fixing unit 108 includes a heating roller and a pressure roller. The fixing unit 108 is positioned at the fixing position P2. The heating roller has a built-in heater. The pressure roller is pressed against the heating roller. The heating roller and the pressure roller are pressed against each other, forming a fixing nip at the fixing position P2.

[0025] In a print job, the sheet S, which has undergone the toner image transfer process, passes through the fixing position P2. That is, the sheet S is sandwiched in the fixing nip between the heating roller and the pressure roller. The fixing unit 108 heats the sheet S as it passes through the fixing position P2. Pressure is applied to the sheet S at the fixing position P2. The fixing unit 108 fixes the toner image to the sheet S by heating and pressurizing the sheet S that has undergone the toner image transfer process. After the fixing process, the sheet S is discharged into the discharge tray ET.

[0026] The image forming apparatus 100 includes a transport unit (the reference numerals are omitted). The transport unit includes a transport roller pair. The transport roller pair includes a pair of rollers. The pair of rollers has a transport nip between them. The transport roller pair transports the sheet S that enters the transport nip by rotating. The transport unit transports the sheet S along the main transport path MP. The transport unit also transports the sheet S along the double-sided printing transport path DP, which will be described later.

[0027] The image forming apparatus 100 is capable of performing both single-sided printing jobs, in which a toner image is printed on only one side of a sheet S, and double-sided printing jobs, in which a toner image is printed on both sides of a sheet S. To perform double-sided printing jobs, the image forming apparatus 100 is equipped with a double-sided printing transport path DP.

[0028] The duplex printing transport path DP branches off from the main transport path MP at branching point P3, which is downstream of the fixing position P2 in the sheet transport direction. Then, the duplex printing transport path DP rejoins the main transport path MP at merging point P4, which is upstream of the transfer position P1 in the sheet transport direction.

[0029] If the execution job is a single-sided printing job, the sheet S passes through the transfer nip only once, and the transfer process is performed once on the sheet S while it is passing through the transfer nip. After the first transfer process, the sheet S is then discharged into the output tray ET.

[0030] If the execution job is a duplex printing job, the sheet S passes through the transfer nip twice, as the transfer process is performed once on each side of the sheet S. Specifically, when the sheet S passes through the transfer nip for the first time, the transfer process is performed on one side of the sheet S. After the first transfer process, the sheet S is switched back after the rear end of the sheet S has passed the branching position P3 and before the sheet S is completely discharged into the discharge tray ET. This causes the sheet S to be pulled from its rear end into the duplex printing transport path DP.

[0031] Subsequently, the sheet S is transported along the double-sided printing transport path DP. Then, the sheet S on the double-sided printing transport path DP is returned to the main transport path MP from the merging position P4. The sheet S returned to the main transport path MP is transported along the main transport path MP and passes through the transfer nip again. At this time, the orientation of the front and back sides of the sheet S is reversed compared to when it passed through the transfer nip the previous time. As a result, when the sheet S passes through the transfer nip for the second time, the transfer process is performed on the opposite side of the sheet S to the previous side.

[0032] <Configuration of the developing device> The following description will focus on one developing apparatus 1 and explain its configuration, referring to Figures 3 and 4. The basic configuration of each developing apparatus 1 is the same. Therefore, the descriptions of the configurations of other developing apparatuses 1 will be omitted, relying on the explanation below.

[0033] Figure 4 is a cross-sectional view of the developing apparatus 1 cut along the YZ plane. Figure 4 is a schematic representation of the cross-sectional structure of the developing apparatus 1 and does not represent the actual dimensions and shape.

[0034] The developing apparatus 1 includes a developing container 11. The developing container 11 contains a developer containing toner. The developer is, for example, a magnetic one-component developer containing magnetic toner. The developing apparatus 1 supplies the toner contained in the developing container 11 to the photoreceptor drum 101.

[0035] The developing container 11 is a container whose longitudinal direction is in the X direction. That is, the developing container 11 is positioned so that its longitudinal direction is in the X direction. As a result, the developing container 11 extends parallel to the axis of the photoreceptor drum 101.

[0036] The developing apparatus 1 includes a developing roller 12. The developing roller 12 is located inside the developing container 11. The developing roller 12 is supported so as to be rotatable around an axis extending in the X direction.

[0037] The developing roller 12 exposes a portion of its outer surface from the inside to the outside of the developing container 11. Specifically, the developing container 11 has an opening (not shown in numerals) at a position facing the photoreceptor drum 101. A portion of the outer surface of the developing roller 12 is exposed through this opening in the developing container 11. As a result, the outer surface of the developing roller 12 faces the outer surface of the photoreceptor drum 101. The developing roller 12 carries toner on its outer surface and supplies toner to the electrostatic latent image on the outer surface of the photoreceptor drum 101.

[0038] The developing apparatus 1 comprises two agitation screws 13. Each agitation screw 13 is located inside the developing container 11. Each agitation screw 13 is supported so as to be rotatable around an axis extending in the X direction.

[0039] Each agitator screw 13 has a structure in which blades are spirally wound around its axis of rotation. Each agitator screw 13 conveys the developer in the X direction while agitating it as it rotates. Each agitator screw 13 conveys the developer in opposite directions to each other.

[0040] The developing container 11 has a container base 110. The container base 110 constitutes the lower part of the developing container 11. For example, the container base 110 has a partition portion 110a that is erected on top. The partition portion 110a of the container base 110 divides the space for installing each agitation screw 13.

[0041] Furthermore, the developing container 11 has a container cover CV. The container cover CV is attached to the container base 110 from above. The area enclosed by the container base 110 and the container cover CV becomes the storage area of ​​the developing container 11.

[0042] The container base 110 is made of metal, such as aluminum. For example, the container base 110 is formed by machining a molded product formed by a mold. On the other hand, the container cover CV is made of resin, for example.

[0043] <Cooling unit configuration> The configuration of the cooling unit 2 will be explained below with reference to Figures 5 to 10.

[0044] The cooling unit 2 includes a cooling tube 3. The cooling tube 3 is made of metal. The material of the cooling tube 3 is not particularly limited, and copper, aluminum, etc., can be used. The internal space of the cooling tube 3 serves as a flow path for the coolant. The cooling unit 2 cools the developing apparatus 1 by circulating the coolant along the cooling tube 3.

[0045] In a plan view from the Z direction, the cooling tube 3 extends to one side in the X direction, curves and folds back midway, and extends to the other side in the X direction. That is, in a plan view from the Z direction, the cooling tube 3 has a shape that is bent into a roughly U shape. As a result, the cooling tube 3 has a pair of end openings on the same side in the X direction.

[0046] Each cooling tube 3 is assigned to each developing unit 1; that is, there are four cooling tubes 3 in total. Each cooling tube 3 has the same structure as the others. Each cooling tube 3 is positioned below the corresponding developing unit 1. Each cooling tube 3 cools the corresponding developing unit 1.

[0047] The cooling unit 2 includes heat dissipation members 4. One heat dissipation member 4 is assigned to each developing device 1. In other words, one heat dissipation member 4 is assigned to each cooling tube 3. Each heat dissipation member 4 is positioned in the Z-direction between the corresponding developing device 1 and the cooling tube 3 located below it. Each heat dissipation member 4 is in contact with the corresponding developing device 1 (specifically, the lower surface of the container base 110). Each heat dissipation member 4 is also in contact with the corresponding cooling tube 3.

[0048] As a result, each heat dissipation member 4 conducts heat between the corresponding developing unit 1 and the cooling pipe 3 located below it. In other words, each developing unit 1 is thermally connected to the corresponding cooling pipe 3 via the corresponding heat dissipation member 4.

[0049] The cooling unit 2 comprises a radiator 5, a tank 6, and a pump 7. The radiator 5 cools the coolant flowing in from the cooling pipes 3. The coolant is air-cooled by a fan. The tank 6 stores the coolant cooled by the radiator 5. The pump 7 pressurizes the coolant from the tank 6 and sends it to the cooling pipes 3. In other words, the pump 7 circulates the coolant.

[0050] The cooling unit 2 includes connecting pipes 8. The connecting pipes 8 are made of materials such as silicone tubing and rubber tubing, and are elastic. The connecting pipes 8 have an internal space that serves as a flow path for cooling water. The connecting pipes 8 connect the radiator 5 and the tank 6, and allow cooling water to flow between the radiator 5 and the tank 6. The connecting pipes 8 also connect the tank 6 and the pump 7, and allow cooling water to flow between the tank 6 and the pump 7.

[0051] Furthermore, the connecting pipe 8 connects the internal space of each cooling pipe 3 to the outside. The four cooling pipes 3 are connected in series by the connecting pipe 8. The end opening of the upstreammost cooling pipe 3 in the direction of cooling water flow is connected to the pump 7. The end opening of the downstreammost cooling pipe 3 in the direction of cooling water flow is connected to the radiator 5. As a result, the cooling water in the tank 6 is pumped by the pump 7, flows through the four cooling pipes 3 to the radiator 5, is cooled, and returns to the tank 6. In other words, the cooling water circulates.

[0052] The cooling unit 2 includes a retaining member 9. One retaining member 9 is assigned to each cooling tube 3. In other words, one retaining member 9 is assigned to each heat dissipation member 4. To put it another way, one retaining member 9 is assigned to each developing device 1.

[0053] Each cooling tube 3 is attached to its corresponding retaining member 9. Each heat dissipation member 4 is attached to its corresponding retaining member 9. Each heat dissipation member 4 covers its corresponding cooling tube 3 from above by being attached to its corresponding retaining member 9.

[0054] The cooling unit 2 includes a pressing member 90. One pressing member 90 is assigned to each holding member 9. Each pressing member 90 is positioned below the corresponding holding member 9. Each pressing member 90 presses the corresponding holding member 9 upward. This ensures that each heat dissipation member 4 makes secure contact with the corresponding developing device 1 (the lower surface of its container base 110).

[0055] Each pressing member 90, although not shown, includes a pressing piece and a compression coil spring. The pressing piece contacts the lower surface of the corresponding retaining member 9. The compression coil spring generates a biasing force that biases the pressing piece upward.

[0056] Furthermore, the pressing member 90 is rotatable about an axis AX extending in the X direction. Each pressing member 90 can be selectively positioned between a pressing position and a release position by rotating about axis AX. Figure 6 shows the pressing member 90 positioned in the pressing position, and a dashed line shows a portion of the outer shape of the pressing member 90 when it is positioned in the release position.

[0057] Each pressing member 90, when positioned in a pressing position, presses the corresponding holding member 9 upward. Each pressing member 90, when positioned in a release position, releases the pressure on the corresponding holding member 9.

[0058] For example, the image forming apparatus 100 includes a main body cover (not shown) that covers the inside of the main body. The main body cover is openable and closable. The main body cover opens by being displaced in one direction around a predetermined axis from a closed state, exposing the inside of the main body. The main body cover closes by being displaced in the other direction around a predetermined axis from an open state, covering the inside of the main body. When the main body cover is opened, it exposes each developing device 1. When the main body cover is closed, it covers each developing device 1.

[0059] Each pressing member 90 rotates around the axis AX as a pivot point in conjunction with the opening and closing of the main body cover. Each pressing member 90 is displaced from the pressed position toward the release position when the main body bar is opened. Each pressing member 90 is displaced from the release position toward the pressed position when the main body cover is closed.

[0060] As a result, when the main body cover is closed, each pressing member 90 presses the corresponding retaining member 9 upward. When the main body cover is open, each pressing member 90 releases the pressure on the corresponding retaining member 9.

[0061] Here, each developing device 1 is detachable from the main body of the image forming apparatus 100. Each developing device 1 can be removed from the main body of the image forming apparatus 100 by being pulled out in the X direction from the main body of the image forming apparatus 100. Each developing device 1 can be attached to the main body of the image forming apparatus 100 by being inserted toward the main body of the image forming apparatus 100 in the X direction.

[0062] When attaching or detaching any of the developing devices 1 (referred to here as the target developing device 1), the main body cover is opened, releasing the upward pressure on each holding member 9. This reduces the Z-direction pressing force from the corresponding heat dissipation member 4 to each developing device 1, including the target developing device 1. In other words, the contact pressure between each developing device 1 and the corresponding heat dissipation member 4 is reduced. This allows the target developing device 1 to be pulled out or inserted into the main body of the image forming apparatus 100.

[0063] <Cooling pipe> The following explanation will focus on one cooling tube 3, referring to Figures 8 and 9. The basic structure of each cooling tube 3 is the same. Therefore, the explanation of the structures of the other cooling tubes 3 will be omitted, relying on the explanation below.

[0064] The cooling tube 3 has a heat receiving portion 31. The portion of the cooling tube 3 other than the end in the extension direction of the cooling tube 3 and other than the U-shaped curved portion is the heat receiving portion 31. At least the heat receiving portion 31 of the cooling tube 3 is in contact with the heat dissipation member 4.

[0065] Furthermore, the cooling tube 3 has connecting portions 32. Both ends of the cooling tube 3 in the direction of extension each become connecting portions 32. The connecting portions 32 are inserted into the connecting tube 8. In this way, the connecting portions 32 are connected to the connecting tube 8. For example, with the connecting portions 32 inserted into the connecting tube 8, the connecting tube 8 is fixed to the connecting portions 32 with a connecting member 80 such as a cable tie.

[0066] In this embodiment, the heat receiving section 31 is flattened in the direction facing the developing apparatus 1 across the heat dissipation member 4 (i.e., the Z direction). In a cross-sectional view taken by cutting the heat receiving section 31 with a plane perpendicular to the extension direction of the cooling tube 3, the heat receiving section 31 has a pair of flat sections facing each other in the Z direction. In other words, in a cross-sectional view taken by cutting the heat receiving section 31 with a plane perpendicular to the extension direction of the cooling tube 3, the heat receiving section 31 has an outer shape that is approximately oval with the Z direction as its shorter side.

[0067] For example, by press-forming the metal circular tube that is the material for the cooling tube 3, the portion of the circular tube that will become the heat receiving portion 31 is flattened. The ends of the circular tube in the direction of extension (i.e., the portions that will become the connection portions 32) are cylindrical.

[0068] In this embodiment, by flattening the cooling tube 3 in the Z direction, the contact area between the cooling tube 3 and the heat dissipation member 4 can be increased, even if the cooling tube 3 is a metal tube (in other words, even if the cooling tube 3 does not undergo elastic deformation). This improves the thermal conductivity between the developing apparatus 1 and the cooling tube 3 via the heat dissipation member 4. As a result, the developing apparatus 1 can be cooled efficiently.

[0069] For example, if rubber tubing or silicone tubing is used as the cooling tube 3, compressing the cooling tube 3 in the Z direction will cause it to elastically flatten. Therefore, using rubber tubing or silicone tubing as the cooling tube 3 allows for a larger contact area between the cooling tube 3 and the heat dissipation member 4. However, rubber tubing and silicone tubing have lower thermal conductivity than metal tubing.

[0070] Therefore, in this embodiment, a metal tube is used as the cooling tube 3, and the metal tube is flattened in the Z direction. As a result, the cooling effect of the developing apparatus 1 is improved compared to when rubber tubes, silicone tubes, etc. are used as the cooling tube 3.

[0071] As a variation, it is not necessary to interpose the heat dissipation member 4 between the developing device 1 and the cooling pipe 3. That is, the developing device 1 (the lower surface of its container base 110) and the cooling pipe 3 may be in direct contact. In this configuration, if the cooling pipe 3 is a cylindrical pipe, the contact area between the developing device 1 and the cooling pipe 3 will be small. However, if the cooling pipe 3 is a flattened pipe, the contact area between the developing device 1 and the cooling pipe 3 will be larger than when the cooling pipe 3 is a cylindrical pipe. In other words, by flattening the cooling pipe 3 in the Z direction, the cooling effect of the developing device 1 can be improved without using the heat dissipation member 4.

[0072] Furthermore, in this embodiment, the boundary portion 30 of the cooling tube 3 between the heat receiving portion 31 and the connection portion 32 is bent. The boundary portion 30 is inclined diagonally downward from the boundary side with the heat receiving portion 31 toward the boundary side with the connection portion 32. In other words, the boundary portion 30 is inclined toward the boundary side with the connection portion 32 toward the developing device 1 (i.e., the heat dissipation member 4).

[0073] In this embodiment, the boundary portion 30 between the heat receiving portion 31 and the connecting portion 32 of the cooling tube 3 is bent, so that the connecting portion 32 is positioned below the heat receiving portion 31. That is, the connecting portion 32 is positioned further away from the developing device 1 (i.e., the heat dissipation member 4) than the heat receiving portion 31.

[0074] If the boundary portion 30 were not bent, a portion of the connecting member 80, which is positioned at the connection point between the cooling pipe 3's connection portion 32 and the connecting pipe 8, would protrude above the heat receiving portion 31. In this case, the heat dissipation member 4 would float above the cooling pipe 3. As a result, a portion of the heat receiving portion 31 and the heat dissipation member 4 would not be in contact.

[0075] On the other hand, in this embodiment, it is possible to suppress the connecting member 80 from protruding above the heat receiving portion 31. This ensures that the heat receiving portion 31 can reliably come into contact with the heat dissipation member 4.

[0076] Furthermore, in this embodiment, the connecting portion 32 has a large-diameter portion 321 and a small-diameter portion 322. The large-diameter portion 321 is the portion on the boundary portion 30 side. The small-diameter portion 322 is the portion on the opposite side of the boundary portion 30 (i.e., the tip portion) and has a smaller outer diameter than the large-diameter portion 321. The large-diameter portion 321 of the connecting portion 32 is not inserted into the connecting pipe 8. Only the small-diameter portion 322 of the connecting portion 32 is inserted into the connecting pipe 8, thereby connecting the connecting portion 32 to the connecting pipe 8.

[0077] As a result, even when the connecting portion 32 (specifically, the small-diameter portion 322) is inserted into the connecting pipe 8 and the connecting pipe 8 is fixed to the connecting portion 32 with the connecting member 80, it is possible to reliably prevent a part of the connecting member 80 from protruding above the heat receiving portion 31.

[0078] Furthermore, in this embodiment, knurled grooves 3220 are formed on the outer circumferential surface of the small-diameter portion 322. The knurled grooves 3220 extend in the circumferential direction of the small-diameter portion 322. The small-diameter portion 322 has multiple knurled grooves 3220 on its outer circumferential surface. This prevents the connecting pipe 8 from coming off the small-diameter portion 322.

[0079] Furthermore, in this embodiment, the cooling tube 3 is substantially U-shaped when viewed from the Z direction in plan. This makes it easy to increase the contact area between the cooling tube 3 and the heat dissipation member 4.

[0080] <Heat dissipation component> The following explanation will focus on one heat dissipation member 4, referring to Figure 10. The basic configuration of each heat dissipation member 4 is the same. Therefore, the explanation of the configurations of the other heat dissipation members 4 will be omitted, relying on the explanation below.

[0081] In this embodiment, the heat dissipation member 4 has an elastically deformable portion. At least the portion of the heat dissipation member 4 that contacts the cooling pipe 3 is elastically deformable. Specifically, the heat dissipation member 4 includes a first sheet 41 and a second sheet 42. The first sheet 41 is in contact with the cooling pipe 3. The second sheet 42 is in contact with the developing device 1 (specifically, the lower surface of the container base 110). In this configuration, the first sheet 41 is elastically deformable.

[0082] As a result, in this embodiment, when the cooling tube 3 and the heat dissipation member 4 are brought into contact with each other, even if there are irregularities on the outer surface of the cooling tube 3, the first sheet 41 elastically deforms along the shape of the outer surface of the cooling tube 3, thereby increasing the contact area between the cooling tube 3 and the heat dissipation member 4. The increased contact area between the cooling tube 3 and the heat dissipation member 4 improves the thermal conductivity between the developing apparatus 1 and the cooling tube 3 via the heat dissipation member 4. As a result, the developing apparatus 1 can be cooled efficiently.

[0083] In this embodiment, the first sheet 41 is more elastically deformable than the second sheet 42. This allows the first sheet 41 to be easily elastically deformed to conform to the shape of the outer surface of the cooling tube 3. In other words, the contact area between the cooling tube 3 and the heat dissipation member 4 can be easily increased.

[0084] On the other hand, in this embodiment, the second sheet 42 has higher sliding properties than the first sheet 41. As a result, when attaching or detaching either developing device 1 (referred to here as the target developing device 1) to or from the main body of the image forming apparatus 100, even if the target developing device 1 (the lower surface of its container base 110) is in contact with the heat dissipation member 4, the target developing device 1 can be smoothly pulled out or inserted with little resistance.

[0085] In this embodiment, the first sheet 41 is a silicone sheet. This makes it easy to give the first sheet 41 elasticity without impairing its thermal conductivity. The second sheet 42 is a metal sheet. Copper, aluminum, and stainless steel may be used as the constituent material of the second sheet 42. This makes it easy to improve the sliding properties of the second sheet 42 without impairing its thermal conductivity. Furthermore, because the first sheet 41 is a silicone sheet, insulation between the developing apparatus 1 and the cooling tube 3 can be ensured.

[0086] In this embodiment, the second sheet 42 covers the first sheet 41 from above. The second sheet 42 also has a mounting portion 420 that protrudes from the first sheet 41 in the X direction (i.e., in a direction perpendicular to the direction facing the developing apparatus 1). With the first sheet 41 covered from above by the second sheet 42, the mounting portion 420 is attached to the holding member 9. In this way, by attaching the second sheet 42 to the holding member 9, the first sheet 41 can be fixed to the holding member 9.

[0087] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the description of the embodiments above, and furthermore, all modifications within the meaning and scope equivalent to the claims are included. [Explanation of Symbols]

[0088] 1. Developing device 2 Cooling Units 3 Cooling pipe 4 Heat dissipation components 8 connecting pipes 30 Boundary part 31 Heat receiving part 32 Connection part 41 Sheet 1 42 Second seat 100 Image forming apparatus 321 Large diameter section 322 Small diameter section 3220 knurled groove

Claims

1. A developing device that develops an electrostatic latent image into a toner image, The developing apparatus comprises a cooling unit that cools the developing apparatus with a cooling liquid, The cooling unit is A cooling tube consisting of a metal tube, the internal space of the tube having a flow path for the cooling liquid, The system includes a heat dissipation member disposed between the cooling tube and the developing device, in contact with the cooling tube and the developing device, and performing heat conduction between the cooling tube and the developing device, The portion of the heat dissipation member that contacts the cooling pipe is elastically deformable, in an image forming apparatus.

2. The heat dissipation member is A first sheet that contacts the cooling tube, It includes a second sheet that comes into contact with the developing device, The first sheet is more elastically deformable than the second sheet. The image forming apparatus according to claim 1, wherein the second sheet has higher sliding properties than the first sheet.

3. The first sheet is a silicone sheet, The image forming apparatus according to claim 2, wherein the second sheet is a metal sheet.

4. The image forming apparatus according to claim 1, wherein the cooling tube has a U-shaped form when viewed from a direction facing the developing apparatus with the heat dissipation member in between.

5. The cooling tube has a heat receiving portion that contacts the heat dissipation member, The image forming apparatus according to any one of claims 1 to 4, wherein the heat receiving portion is flattened in a direction facing the developing apparatus with the heat dissipation member in between.

6. The cooling unit includes a connecting pipe that connects the internal space of the cooling tube to the outside, The cooling tube has an end in the extension direction of the cooling tube as a connecting portion. The connecting portion is connected to the connecting pipe by being inserted into the connecting pipe. The image forming apparatus according to claim 5, wherein the boundary portion of the cooling tube between the heat receiving portion and the connecting portion is bent so that the connecting portion is positioned further away from the developing apparatus than the heat receiving portion.

7. The aforementioned connecting portion is cylindrical, The aforementioned connection part is The large diameter portion is the portion on the boundary side, The portion opposite to the boundary portion has a smaller diameter portion with a smaller outer diameter than the larger diameter portion, The image forming apparatus according to claim 6, wherein the small-diameter portion is inserted into the connecting pipe, thereby connecting the connecting portion to the connecting pipe.

8. The image forming apparatus according to claim 7, wherein the small diameter portion has knurled grooves extending in the circumferential direction of the small diameter portion on its outer surface.

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