Developing device and image forming apparatus

Abstract

To lower the temperature of a developer passing near a continuous hole, compared with an apparatus in which parts of the transportation path that adjoin the continuous hole are made of a material with the same heat transfer coefficient as the other parts of the housing.SOLUTION: A housing having a first transportation path and a second transportation path that adjoin the first transportation path; a first transportation member and a second transportation member that transport a developer by circulating it between the first transportation path and the second transportation path via a continuous hole; and a cooling unit which is arranged at a position adjoining the continuous hole in the housing and made from materials with a higher heat transfer coefficient than the housing: are provided.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a developing device and an image forming apparatus. [Background technology]

[0002] Patent Document 1 discloses a developing device having a developing container that contains a developer, an agitator that transports the developer while stirring it, a developing sleeve that rotates by adsorbing the developer transported by the agitator to its surface, and a developing blade that is arranged with a uniform minute gap with respect to the surface of the developing sleeve and that regulates the amount of developer adsorbed on the surface of the developing sleeve to be thin and uniform. The developing device and image forming device equipped with the developing device have at least one cooling means among a cooling means that contacts the agitator inside the developing container and absorbs heat from the agitator, a cooling means that contacts the developing sleeve inside the developing container and absorbs heat from the developing sleeve, and a cooling means that contacts the developing blade inside the developing container and absorbs heat from the developing blade, and the developing device and image forming device equipped with the developing device are characterized in that the heat dissipation portion of the cooling means is arranged outside the developing container and outside the transport area of ​​the transfer material when the image forming device is viewed from above. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-114577 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention aims to reduce the temperature of the developer passing near the communication hole compared to when the portion of the transport path adjacent to the communication hole is made of a material with the same thermal conductivity as the other parts of the housing. [Means for solving the problem]

[0005] The developing device according to a first aspect includes a housing having a first transport path and a second transport path adjacent to the first transport path, a first transport member and a second transport member that transport developer so as to circulate it between the first transport path and the second transport path through a communication hole, and a cooling section that is disposed at a position adjacent to the communication hole in the housing and is formed of a material having a higher thermal conductivity than the housing.

[0006] In a developing device according to a second aspect, the first transport member is formed to be capable of supplying developer to the surroundings, the second transport member is formed to be capable of stirring the developer, and the cooling section is arranged in the second transport path.

[0007] In the developing device according to a third aspect, the first transport path and the second transport path are disposed adjacent to each other in the vertical direction in the gravitational force direction, and the second transport path is located below the first transport path.

[0008] In a developing device according to a fourth aspect, the cooling section is disposed adjacent to the communication hole that lifts the developer upward and transfers it from the second transport path to the first transport path.

[0009] In a developing device according to a fifth aspect, the cooling section is a pipe-shaped member that covers an inner surface of the second transport path.

[0010] In a developing device according to a sixth aspect, the cooling portion has a cutout portion corresponding to the communication hole.

[0011] In a developing device according to a seventh aspect, the second transport member has a reverse winding portion wound in the opposite direction to the main winding portion at an end opposite to the main winding portion formed to circulate the developer through the communicating hole of the second transport path, and the cooling portion is arranged from a position adjacent to the communicating hole of the second transport path to a position corresponding to the reverse winding portion.

[0012] In the developing device of the eighth aspect, a developer discharge path is arranged through which excess developer discharged from outside the range in which the developer circulates through the communication hole in the first transport path is discharged to the outside, and the cooling section is arranged from a position adjacent to the communication hole to a position adjacent to the developer discharge path. An image forming apparatus according to a ninth aspect includes a holder for holding a latent image, and the developing device according to any one of the first to eighth aspects for developing the latent image on the holder with a developer. Effect of the Invention

[0013] According to the first aspect, the temperature of the developer passing near the communication hole can be reduced compared to when the portion of the transport path adjacent to the communication hole is made of a material with the same thermal conductivity as the other portions of the housing.

[0014] According to the second aspect, it is possible to effectively suppress the temperature rise, compared to a case where a cooling unit is provided only on the first transport path.

[0015] According to the third aspect, in a configuration in which the second transport path is arranged below the first transport path in the direction of gravity, the temperature of the developer passing near the communication hole can be reduced compared to a configuration in which the portion of the transport path adjacent to the communication hole is made of a material having the same thermal conductivity as the portion of the transport path adjacent to the communication hole.

[0016] According to the fourth aspect, the temperature of the developer passing near the communication hole can be reduced compared to a configuration in which the developer is disposed adjacent only to the communication hole through which the developer moves from the first transport path to the second transport path.

[0017] According to the fifth aspect, the temperature of the developer passing near the communication hole can be lowered as compared to when the cooling portion is plate-shaped.

[0018] According to the sixth aspect, the cooling portion can reduce the temperature of the developer passing near the communication hole, compared to a case in which the cooling portion is disposed offset from the communication hole. According to the seventh aspect, the temperature of the developer passing near the communication hole can be lowered, as compared to a case in which the cooling portion is arranged offset from the reverse-winding portion.

[0019] According to the eighth aspect, in comparison with a case in which the cooling portion is disposed only in the vicinity of the communication hole, poor discharge of the excess developer is suppressed.

[0020] According to a ninth aspect, it is possible to provide an image forming apparatus including the developing device according to any one of the first to eighth aspects. [Brief description of the drawings]

[0021] [Figure 1] 1 is a side view illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an external perspective view showing a developing device according to the embodiment of the present invention. [Diagram 3] FIG. 2 is an external perspective view showing an end portion of a developing device including a support portion according to an embodiment of the present invention. [Figure 4] 1 is a perspective view including a vertical section of a developing device according to an embodiment of the present invention; [Diagram 5] FIG. 2 is a vertical cross-sectional view showing a developing device according to an embodiment of the present invention. [Figure 6] FIG. 2 is a horizontal cross-sectional view showing the developing device according to the embodiment of the present invention. [Figure 7] 4 is a vertical cross-sectional view showing a second transport path and a transport member from which a cooling unit has been removed according to the embodiment of the present invention. FIG. [Figure 8] 4 is a vertical cross-sectional view showing a second transport path and a transport member to which a cooling unit is attached according to the embodiment of the present invention. FIG. [Figure 9] FIG. 4 is a rear view showing an end portion of the developing device according to the embodiment of the present invention. [Figure 10] FIG. 11 is an external perspective view showing an example of another cooling unit according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, the present embodiment will be described with reference to the drawings. Note that the same components and processes are given the same reference numerals throughout the drawings, and duplicated explanations will be omitted.

[0023] FIG. 1 is a side view showing the configuration of an image forming apparatus, FIG. 2 is an external oblique view showing a developing device, FIG. 3 is an external oblique view showing an end of the developing device including a support portion, FIG. 4 is an external oblique view including a vertical section of the developing device, FIG. 5 is a vertical cross-sectional view showing the developing device, FIG. 6 is a horizontal cross-sectional view showing the developing device, FIG. 7 is a vertical cross-sectional view showing a second conveying path and a conveying member with the cooling portion removed, FIG. 8 is a vertical cross-sectional view showing the second conveying path and a conveying member with the cooling portion attached, FIG. 9 is a rear view showing the end of the developing device, and FIG. 10 is an external oblique view showing an example of another cooling portion.

[0024] Next, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 shows an image forming apparatus 10 used in the embodiment of the present invention. The image forming apparatus 10 has an image forming apparatus main body 12 in which an image forming section 14, a transfer device 16, a fixing device 18, and a paper feed device 20 are arranged. In addition, a transport path 22 for transporting a recording medium such as paper is formed in the image forming apparatus main body 12. For convenience, in this specification and drawings, the left-right direction of the image forming apparatus 10 in Fig. 1 is shown as the X-axis direction, the height direction as the Y-axis direction, and the direction perpendicular to the X-axis direction and the Y-axis direction as the Z-axis direction. Also, the right direction in Fig. 1 is defined as the positive side in the X-axis direction, the upward direction as the positive side in the Y-axis direction, and the front direction as the positive side in the Z-axis direction, and similar directions are used in the other drawings.

[0025] The image forming section 14 employs an electrophotographic method and forms an image on a recording medium. The image forming section 14 has, for example, a plurality of, for example, four, image forming units 24. The four image forming units 24 form toner images of different colors, for example, yellow, magenta, cyan, and black.

[0026] The image forming unit 24 has a photoconductor drum 26. The photoconductor drum 26 is an example of an image carrier, and rotates while holding a toner image to be transferred to a recording medium on its outer circumferential surface. The image forming unit 24 is also provided with a charging device 28 that charges the photoconductor drum 26, a developing device 95 that develops the charged latent image with toner, and a cleaning device 32 that cleans the photoconductor drum 26 after transfer. An optical writing device 48 that forms a latent image on the charged photoconductor drum 26 is also provided.

[0027] The transfer device 16 has an intermediate transfer belt 34. The toner images are primarily transferred from the photoconductor drums 26 onto the intermediate transfer belt 34 by a primary transfer member 36, and the primarily transferred toner images are secondarily transferred onto a recording medium by a secondary transfer member 38.

[0028] The intermediate transfer belt 34 is supported so as to be rotatable by a plurality of support members 40. In addition, a backup member 42 is provided opposite the secondary transfer member 38.

[0029] The fixing device 18 fixes the toner image transferred onto the recording medium onto the recording medium using, for example, heat and pressure.

[0030] The paper feeder 20 has a storage section 44 that stores recording media in a stacked state, and a delivery member 46 that delivers the recording media stored in the storage section 44 toward the transport path 22 .

[0031] The transport path 22 transports the recording medium from the paper feed device 20 to between the secondary transfer member 38 and the backup member 42, then transports the recording medium to the fixing device 18, and further transports the recording medium so that it is discharged outside the image forming device main body 12.

[0032] In the image forming apparatus 10 configured as described above, the toner images formed on the outer peripheral surfaces of the photosensitive drums 26 are primarily transferred to the intermediate transfer belt 34, the toner images primarily transferred to the intermediate transfer belt 34 are secondarily transferred to a recording medium, and the toner images secondarily transferred to the recording medium are fixed to the recording medium by the fixing device 18.

[0033] In the image forming apparatus 10 according to the present embodiment, a developing device 95 is used that develops the electrostatic latent image formed on the electrostatic latent image holder of the photosensitive drum 26. As such a developing device 95, for example, a two-component developer (hereinafter simply referred to as developer) consisting of a magnetic carrier and a resin-based toner is accommodated in a housing 300 (housing) having a development opening opened facing the electrostatic latent image holder (photosensitive drum 26), and a developing roll 190 as a developer holder is disposed at a location facing the development opening of the housing 300 as the housing. An auger is disposed on the back side of the developing roll 190 as a transport member that transports the developer inside the transport path in the housing 300 (housing) while stirring and transporting it to the developing roll.

[0034] As shown in FIGS. 1 to 9, the developing device 95 according to the present embodiment has a housing 300 as a casing that has an opening facing the photosensitive drum 26 and contains a developer. A developing roll 190 as a developing member that is a developer holder is disposed facing the opening of the housing 300. Inside the housing 300 as an example of a casing, a first conveying path 100 that contains the developer so as to be able to supply it to the developing roll 190 is provided at a portion adjacent to the developing roll 190, and a second conveying path 150 that is disposed adjacent to the first conveying path 100 and contains the developer so as to be able to supply it to the first conveying path 100. As shown in FIG. 4, the first conveying path 100 and the second conveying path 150 are disposed adjacent to each other in the vertical direction in the direction of gravity, and the second conveying path 150 is formed so as to be located below the first conveying path 100.

[0035] Here, the first transport path 100 and the second transport path 150 are separated from each other by a partition wall, and communicate with each other at both axial ends. Specifically, a communication hole 110 (see FIG. 5) is formed at the front end, and a communication hole (not shown) is formed at the back end. Inside the housing 300, the developer circulates in the order of the second transport path 150, the front communication hole 110, the first transport path 100, and the back communication hole.

[0036] The developing device 95 includes a conveying member that applies a conveying force to circulate the developer in the housing 300. Specifically, the developing device 95 includes a supply auger 120 disposed in the first conveying path 100 and an admix auger 170 disposed in the second conveying path 150. The supply auger 120 has a main winding portion 180, which is a spiral blade, formed on the outer periphery of the shaft, and conveys the developer in a predetermined axial direction (for example, the negative side of the Z-axis direction in FIG. 5) while supplying the developer to the developing roll 190 by rotating about the shaft. The admix auger 170 has a main winding portion 180, which is a spiral blade, formed on the outer periphery of the shaft, and conveys the developer in a direction opposite to the supply auger 120 (for example, the positive side of the Z-axis direction in FIG. 5) while stirring the developer by rotating about the shaft. The supply auger 120 is an example of a first conveying member, and the admix auger 170 is an example of a second conveying member.

[0037] The rotation of the supply auger 120 and the admix auger 170 causes the developer G to circulate through the above-mentioned route. The second transport path 150 extends forward of the communication hole 110, and in this portion, a reverse wound portion 185, which is a spiral blade, is formed on the outer periphery of the shaft of the admix auger 170. The reverse wound portion 185 imparts a transport force to the developer in the opposite direction to that of the main winding portion 180, thereby promoting the lifting of the developer that has been transported to the communication hole 110 by the main winding portion toward the communication hole 110.

[0038] On the other hand, the first transport path 100 extends forward from the communication hole 110 and forms a part of a developer discharge path 186 that discharges excess developer. The developer discharge path 186 is composed of a part that extends forward from the communication hole 110 in the first transport path 100 beyond the reverse winding portion 185 of the admix auger 170 to the positive side in the Z direction, and a part that extends downward from the end of the part and penetrates the second transport path 150 in the vertical direction. The developer discharge path 186 is formed, so that a so-called trickle method is adopted in which deteriorated developer is gradually discharged to the outside of the housing 300. In the part of the developer discharge path 186 extending in the Z direction, a part is arranged in which a reverse winding portion 185 is formed that imparts a transport force to the developer in the opposite direction to that of the main winding portion 180 in the supply auger 120.

[0039] In this embodiment, the housing 300 is formed with a third transport path 195 in which a counter auger 196, which is a third transport member, is disposed. The counter auger 196 returns the developer not consumed by the developing roll 190 to the second transport path 150 by rotating about its axis.

[0040] The housing 300 is constructed by joining a main body housing 320 and an end housing 340. The main body housing 320 is formed with the first transport path 100 and the second transport path 150 up to a portion slightly before the communication hole 110. The end housing 340 is formed with the remaining portions of the first transport path 100 and the second transport path 150. The main body housing 320 and the end housing 340 are fixed to each other by screwing fastening members 342, 344, 346 into the main body housing 320 (housing) from the end housing 340 side in an abutting state with a seal member 156 sandwiched between the ends of the housings.

[0041] As shown in Figs. 3 to 6, in this embodiment, the cooling unit 200 is disposed at a position adjacent to the communication hole 110 of the second conveying path 150. The cooling unit 200 is disposed on the front side of the communication hole 110 in the second conveying path 150. The cooling unit 200 is a pipe-shaped member made of aluminum or an aluminum alloy, which is a material having a higher thermal conductivity than the resin, which is the material of the housing 300. The cooling unit 200 is formed so as to cover the inner surface of the second conveying path 150 at the portion where the cooling unit 200 is disposed and to extend in the circumferential direction of the second conveying path 150. Specifically, the cooling unit 200 covers the reverse winding portion 185 of the admix auger 170 from the periphery.

[0042] The cooling unit 200 is sandwiched between a main body side housing 320 and an end side housing 340 and fixed to the case 300 .

[0043] A specific description will be given below. A recess 152 is formed in a portion of the main body housing 320 where the second transport path 150 is formed. The recess 152 is a portion whose inner diameter is wider than the transport path 150, and reaches the end of the end side housing 340 in the main body housing 320. The end of the recess 152 opposite to the end side housing 340 is an abutment surface facing the end side housing 340. A part of the cooling unit 200 on the negative side in the Z direction is fitted inside the recess 152 in a state where the cooling unit 200 is abutted against the abutment surface of the recess 152. Another part of the cooling unit 200 is fitted inside the end side housing 340. A seal member 154 is interposed between the end side housing 340 and the end of the cooling unit 200 opposite to the main body side housing 320. A fastening load is applied to the seal member 154 by the fastening members 342, 344, 346 described above. That is, as described above, the cooling unit 200 is sandwiched between the main body side housing 320 and the end side housing 340 by the fastening load of the fastening members 342, 344, 346, and fixed to the housing 300.

[0044] 8, the pipe inner diameter of the cooling section 200 and the pipe inner diameter of the second transport path 150 are formed to be the same, and the inner surfaces of both are formed to be continuous without generating any step. However, the pipe inner diameter of the cooling section 200 may be formed to be smaller than the pipe inner diameter of the second transport path 150. This allows the developer transported by the reverse winding section 185 to be smoothly transported in the direction of the communication hole 110 side.

[0045] Moreover, an opening 360 through which the cooling unit 200 faces the outside of the housing is formed in a portion of the housing 300 located outside the cooling unit 200. The opening 360 is formed in a rectangular window shape penetrating the inside and outside of the housing, and is configured to allow the cooling unit 200 to come into contact with the air outside the housing 300.

[0046] In this embodiment, the opening 360 is formed in two places, an upper opening 362 facing diagonally upward from the casing 300 (housing) as shown in Fig. 2, and a lower opening 364 facing downward from the casing 300 (housing) as shown in the rear view of Fig. 9. The opening 360 is provided on a surface parallel to the developer transport direction (positive side in the Z-axis direction) of the second transport path 150. In this embodiment, the upper opening 362 and the lower opening 364 are formed in the end-side housing 340, and the above-mentioned seal member 156 is located on the edge of each of them on the main body-side housing 320 side.

[0047] In addition, in this embodiment, as shown in FIG. 2, the image forming apparatus 10 includes an intake section 420 that draws air into the image forming apparatus 10 and an exhaust section 430 that exhausts the air. The intake section 420 is a section that opens on a plate on the right side when the image forming apparatus 10 is viewed from the side shown in FIG. 1, and the exhaust section 430 is a section that opens on a plate on the back side when the image forming apparatus 10 is viewed from the side shown in FIG. 1. As shown in FIG. 2, when the developing device 95 is installed in the image processing apparatus 90, the cooling section 200 is disposed on the intake section 420 side, not on the exhaust section 430 side. The intake section 420 includes a blower 400 that blows air toward the cooling section 200. Therefore, the opening 360 is provided at a position where the opening 360 comes into contact with an air flow generated inside the image forming apparatus 10 when the developing device 95 is installed in the image forming apparatus 10. Here, intake section 420 is a portion that opens into a plate on the right side when image forming apparatus 10 is viewed from the side shown in Fig. 1, and exhaust section 430 is a portion that opens into a plate on the far side when viewed from the side shown in Fig. 1. Note that the number of intake section 420 and exhaust section 430 is not limited to one, and each developing device 95 may be provided with one. Also, a duct that connects intake section 420 to opening 360 may be provided to facilitate sending the air taken in from intake section 420 to cooling section 200.

[0048] (action) Next, the operation of the above-described embodiment will be described. In the developing device 95, when the supply auger 120 and the admix auger 170 rotate, the developer circulates within the housing 300 in the following order: second transport path 150, the front communication hole 110, the first transport path 100, and the back communication hole.

[0049] In the embodiment described above, the transport direction of the developer in the second transport path 150 (from the negative side in the Z-axis direction to the positive side in the Z-axis direction in FIG. 5) is changed to the transport direction of the developer in the first transport path 100 (from the positive side in the Z-axis direction to the negative side in the Z-axis direction in FIG. 5), and pressure needs to be applied to the developer near the communication hole 110 of the second transport path 150 in order to lift and move the developer upward into the first transport path 100. At that time, the frictional force between the developers increases, generating frictional heat, which increases the temperature of the developer, etc.

[0050] Furthermore, in order to save space in the image forming device, if the conveying members such as the auger shaft are rotated at high speed without increasing their diameter and remaining small, heat will be generated in the bearings and drive system, and the heat generated in the areas where the developer accumulates near the communicating holes will tend to become significant.

[0051] In this embodiment, the cooling unit 200 is disposed adjacent to the communication hole 110. The cooling unit 200 has a higher thermal conductivity than the housing 300.

[0052] According to this embodiment, the temperature of the developer passing near the communication hole 110 can be reduced compared to when the portion of the second transport path 150 adjacent to the communication hole 110 is made of a material having the same thermal conductivity as the other portions of the housing 300.

[0053] According to this embodiment, compared to a case where the cooling unit 200 is provided only on the first transport path 100, it is possible to effectively suppress the temperature rise.

[0054] According to this embodiment, in a configuration in which the second transport path 150 is arranged below the first transport path 100 in the direction of gravity, the temperature of the developer passing near the communication hole 110 can be reduced compared to a configuration in which the portion of the transport path adjacent to the communication hole 110 is made of a material having the same thermal conductivity as that of the material.

[0055] According to this embodiment, compared to a configuration in which the developer is positioned only adjacent to the communication hole 110 through which the developer moves from the first transport path 100 to the second transport path 150, the temperature is more likely to rise near the communication hole 110 for lifting and transferring the developer, and therefore the temperature of the developer passing near the communication hole 110 can be efficiently reduced.

[0056] According to the present embodiment, compared to when the cooling section 200 is plate-shaped, the cooling section 200 is a pipe-shaped member, so that the developer directly contacts the cooling section 200, and the temperature of the developer passing near the communication hole 110 can be reduced.

[0057] According to this embodiment, the cooling section 200 can be positioned close to the periphery of the communicating hole 110, compared to a case in which the cooling section is positioned offset from the communicating hole 110, and the temperature of the developer passing near the communicating hole 110 can be reduced.

[0058] According to this embodiment, compared to a configuration in which the cooling section is positioned offset from the reverse-winding section, it is possible to suppress the temperature rise in the area where the developer collides and where the temperature rise due to friction becomes large, and to lower the temperature of the developer passing near the communicating hole.

[0059] According to this embodiment, compared to a case where the cooling section 200 is arranged only in the vicinity of the communication hole 110, the temperature rise near the developer discharge path 186 can be suppressed, and failure to discharge excess developer can be suppressed.

[0060] According to this embodiment, it is possible to provide an image forming apparatus 10 including the developing device 95 according to any one of the above-mentioned aspects.

[0061] In this embodiment, the developer conveying path has a communication hole 110 that lifts the developer upward and transfers it from the second conveying path 150 to the first conveying path 100, and a communication hole (not shown) that drops the developer downward and transfers it from the first conveying path 100 to the second conveying path 150. Of these two communication holes, as shown in FIG. 5, a cooling section 200 is provided at a position adjacent to the communication hole 110 that lifts the developer upward and transfers it from the second conveying path 150 to the first conveying path 100. The communication hole (not shown) for dropping the developer downward can move the developer by natural drop without applying special pressure or the like to the developer, so that a large friction load is not applied to the developer and frictional heat is also small. For this reason, there is no need to provide a cooling section 200 on the communication hole (not shown) side for dropping the developer downward, and therefore the cooling section 200 is not provided. On the other hand, in the vicinity of the communication hole 110 for lifting the developer and transferring it from the second transport path 150 to the first transport path 100 through the communication hole 110, it is necessary to apply pressure by pushing the developer in order to lift the developer from the lower second transport path 150 to the upper first transport path 100 against gravity. In such a place, the frictional force between the developers becomes large, and the temperature in the vicinity is likely to rise due to frictional heat. By providing the cooling section 200 at a position adjacent to such a communication hole 110 where the temperature is likely to rise, the temperature rise in the vicinity of the communication hole 110 can be efficiently suppressed.

[0062] In the above-described embodiment, as shown in Figs. 3, 5, and 6, when the support portion 340 is fixed to the end portion of the housing 300 by the fastening members (342, 344, 346), the cooling portion 200 is sandwiched between the support portion 340 and the housing 300. Included The support portion 340 is then fixed to the housing 300 by fastening members (342, 344, 346). As a result, compared to a structure in which the cooling unit 200 is fixed to the housing 300 of the developing device 95 using a dedicated fastening mechanism or other such fixture, the cooling unit 200 can be fixed to the developing device 95 without the need for a special fastening mechanism or the like for fixing the cooling unit 200. Also, the structure of the developing device 95 can be simplified without being complicated.

[0063] In the above-described embodiment, the opening 360 is provided in the end side housing (support portion) 340, not in the main body side housing 320. The end side housing (support portion) 340 is formed shorter than the elongated main body side housing 320, so that it becomes possible to open the opening 360 while maintaining the strength and rigidity of the housing.

[0064] 2, the embodiment described above includes intake section 420, so that blower device 400 takes in cool fresh air from outside image forming apparatus 10 through intake section 420 into image forming apparatus 10. Then, the air flow is directly applied to cooling section 200. This allows air whose temperature has increased by absorbing heat emitted from the surface of cooling section 200 to be exhausted to the outside of image forming apparatus 10 through exhaust section 430. In addition, an air flow as shown in FIG. 2 can be generated inside image forming apparatus 10, and the cooling effect of cooling section 200 can be improved without increasing the air temperature inside image forming apparatus 10. The cooling section 200 according to the present embodiment has an overall shape of a cylindrical pipe, and no opening or notch is formed, but is not particularly limited to such a shape. Specifically, for example, as shown in FIG. 10, the cooling section 200 may have a notch 210 cut out at a position corresponding to the communication hole 110. When the notch 210 is formed, it is desirable to arrange the communication hole 110 between one side 211 and the other side 212 facing each other of the notch 210. In this embodiment, the notch 210 is cut out at the end side of the cooling section 200, but the position and shape of the notch 210 are not particularly limited to the notch shape at the end side, and may be formed in a hole shape that opens further inside the cooling section 200.

[0065] As shown in FIG. 10, when the cooling section 200 has a notch 210 corresponding to the communication hole 110, the cooling section 200 can be positioned close to the periphery of the communication hole 110, and the temperature rise around the communication hole 110 can be efficiently suppressed. In addition, in this embodiment, the first transport path 100 and the second transport path 150 are arranged adjacent to each other vertically in the direction of gravity, which is a so-called vertical arrangement, but the present invention is not particularly limited to such a vertical arrangement. Specifically, for example, even if the multiple transport paths are arranged horizontally to the left and right in the direction of gravity instead of the vertical arrangement as described above, the same action and effect can be achieved and the present invention is applicable even if the cooling unit 200 as described above is provided in a developing device that rotates at high speed to increase efficiency and is expected to increase the temperature of the developer due to frictional force.

[0066] The present invention is not limited to the above-described embodiment, and various modifications, changes, and improvements are possible without departing from the spirit and scope of the present invention. For example, the above-described embodiment may be appropriately combined to form a configuration. [Explanation of symbols]

[0067] 10 image forming apparatus, 12 image forming apparatus main body, 14 image forming section, 16 transfer device, 18 fixing device, 20 paper feeder, 22 transport passage, 24 image forming unit, 26 photosensitive drum, 28 charging device, 30 developing device, 32 cleaning device, 34 intermediate transfer belt, 36 primary transfer member, 38 secondary transfer member, 40 support member, 42 backup member, 44 storage section, 46 delivery member, 48 optical writing device, 95 developing device, 100 first transport path, 110 communication hole, 120 first transport member (supply auger), 150 second transport path, 152 recessed portion, 153 stepped portion, 154 sealing member, 156 sealing member, 170 second transport member (admix auger), 180 main winding portion, 185 reverse winding portion, 186 Developer discharge path, 190 developing member (developing roll), 195 third transport path, 196 third transport member (counter auger), 200 cooling section, 210 notch, 211 one side, 212 other side, 300 case (housing), 320 main body side housing, 340 end side housing (support section), 342, 344, 346 fastening member, 360 opening, 362 upper opening, 364 lower opening, 400 blower, 410 air flow, 420 intake section, 430 exhaust section

Claims

1. a housing having a first transport path and a second transport path adjacent to the first transport path; a first transport member and a second transport member that transport the developer so as to circulate the developer between the first transport path and the second transport path via a communication hole; a cooling section disposed adjacent to the communication hole in the housing and made of a material having a higher thermal conductivity than the housing; Equipped with The cooling unit is a pipe-shaped member that covers the inner surface of the second transport path. Developing device.

2. the first transport member is formed to be capable of supplying the developer to the periphery, the second transport member is formed to be capable of stirring the developer, The developing device according to claim 1 , wherein the cooling section is disposed in the second transport path.

3. 3. The developing device according to claim 2, wherein the first transport path and the second transport path are disposed adjacent to each other in the direction of gravity, and the second transport path is located below the first transport path.

4. The developing device according to claim 3 , wherein the cooling portion is disposed adjacent to the communication hole that lifts the developer upward and transfers the developer from the second transport path to the first transport path.

5. 5. The developing device according to claim 1, wherein the cooling portion has a notch corresponding to the communication hole.

6. the second transport member includes a reverse winding portion wound in a direction opposite to that of the main winding portion at an end portion opposite to the main winding portion formed to circulate the developer across the communication hole of the second transport path, 6. The developing device according to claim 1, wherein the cooling portion is disposed from a position adjacent to the communication hole of the second transport path to a position corresponding to the reverse winding portion.

7. a developer discharge path is provided through which excess developer discharged from outside a range in which the developer circulates through the communication hole in the first transport path is discharged to the outside; 7. The developing device according to claim 1, wherein the cooling portion is disposed from a position adjacent to the communication hole to a position adjacent to the developer discharge path.

8. A holder for holding a latent image; 8. An image forming apparatus comprising the developing device according to claim 1, which develops the latent image on the support with a developer.

Images