Image forming apparatus

Abstract

To provide an image forming apparatus that can suppress uneven airflow velocity from the air outlet without increasing the size of the housing. [Solution] The image forming apparatus includes an intake fan 41 provided on the side wall of the housing, an air outlet 51 opening toward the developing apparatus, an extension 52 extending from the intake fan 41 toward the air outlet 51 along the side wall, and a connecting portion 53 connecting the extension end 52A of the extension 52 to the air outlet 51, and a third duct 44 that guides air drawn in from outside the housing by the intake fan 41 to the developing apparatus, and a guide portion 54 provided inside the connecting portion 53 that guides a portion of the airflow flowing into the connecting portion 53 toward the upstream side in the extension direction of the extension 52 at the air outlet 51.

Description

Technical Field

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

Background Art

[0002] An image forming apparatus that air-cools an image forming unit that forms an image on a conveyed sheet is known (see, for example, Patent Document 1).

[0003] For example, this type of image forming apparatus includes an intake fan and a duct. The intake fan is provided on a side wall portion on the first direction side along a width direction orthogonal to the sheet conveyance direction in a housing that houses the image forming unit. The duct guides air sucked from outside the housing by the intake fan to the image forming unit. The duct has a blower port that opens toward the image forming unit at a position on the first direction side of the image forming unit and spaced apart from the intake fan in a direction orthogonal to the first direction, an extending portion that extends from the intake fan toward the blower port along the side wall portion, and a connecting portion that connects an extending end portion in the extending portion and the blower port.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in the image forming apparatus having the connecting portion, the wind speed of the wind blowing out from the downstream side portion in the extending direction of the extending portion at the blower port is faster than the wind speed of the wind blowing out from the upstream side portion in the extending direction at the blower port.

[0006] In contrast, by increasing the length of the air passage in the duct along the first direction to the air outlet, it is possible to suppress unevenness in the wind velocity blown out from the air outlet. However, increasing the length of the air passage in the duct along the first direction to the air outlet increases the size of the housing in the width direction.

[0007] The object of the present invention is to provide an image forming apparatus that can suppress unevenness in the wind velocity blown out from the air outlet without increasing the size of the housing. [Means for solving the problem]

[0008] The image forming apparatus according to the present invention comprises an image forming unit, a housing, an intake fan, a duct, and a guide unit. The image forming unit forms an image on a conveyed sheet. The housing houses the image forming unit. The intake fan is provided on the side wall of the housing on the first direction side, along the width direction perpendicular to the conveying direction of the sheet. The duct has an air outlet that opens toward the image forming unit at a position on the first direction side of the image forming unit and spaced apart from the intake fan in a direction perpendicular to the first direction, an extension portion that extends from the intake fan toward the air outlet along the side wall, and a connecting portion that connects the extension end of the extension portion to the air outlet, and guides air drawn in from outside the housing by the intake fan toward the image forming unit. The guide unit is provided within the connecting portion and guides a portion of the airflow flowing into the connecting portion toward the upstream side of the extension direction of the extension portion toward the air outlet. [Effects of the Invention]

[0009] According to the present invention, it is possible to suppress unevenness in the air velocity of the air blown out from the air outlet without increasing the size of the housing. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a perspective view showing the external configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2] Figure 2 is a cross-sectional view showing the internal configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 3] Figure 3 is a perspective view showing the configuration of the air-cooling section of an image forming apparatus according to an embodiment of the present invention. [Figure 4] Figure 4 is a perspective view showing the configuration of the air-cooling section of an image forming apparatus according to an embodiment of the present invention. [Figure 5] Figure 5 is a perspective view showing the configuration of the third duct of an image forming apparatus according to an embodiment of the present invention. [Figure 6] Figure 6 is a perspective view showing the configuration of the first forming member of an image forming apparatus according to an embodiment of the present invention. [Figure 7] Figure 7 is a perspective view showing a modified example of the third duct of an image forming apparatus according to an embodiment of the present invention. [Figure 8] Figure 8 is a perspective view showing a modified example of the third duct of an image forming apparatus according to an embodiment of the present invention. [Modes for carrying out the invention]

[0011] The embodiments of the present invention will be described below with reference to the attached drawings. Note that the following embodiments are merely examples of the present invention and do not limit the technical scope of the present invention.

[0012] [Configuration of the image forming apparatus 100] First, the configuration of the image forming apparatus 100 according to an embodiment of the present invention will be described with reference to Figures 1 and 2.

[0013] For the sake of explanation, the vertical direction is defined as the up-down direction D1 when the image forming apparatus 100 is in a usable installation state (as shown in Figure 2). The front-to-back direction D2 is defined with the left side of the image forming apparatus 100 shown in Figure 2 as the front. The left-to-right direction D3 is defined with the front of the image forming apparatus 100 in the aforementioned installation state as the reference point.

[0014] The image forming apparatus 100 is a printer having a printing function of forming an image on a sheet. Specifically, the image forming apparatus 100 forms an image on a sheet by an electrophotographic method. Note that the image forming apparatus 100 may form an image on a sheet by an image forming method different from the electrophotographic method such as an inkjet method. Further, the image forming apparatus of the present invention is not limited to a printer, and any apparatus having the printing function may be used.

[0015] As shown in FIGS. 1 and 2, the image forming apparatus 100 includes a housing 1, a sheet conveyance unit 2, and an image forming unit 3.

[0016] The housing 1 houses the components of the image forming apparatus 100 including the image forming unit 3.

[0017] As shown in FIG. 1, the housing 1 is formed in a substantially rectangular parallelepiped shape. On the upper surface portion of the housing 1, a paper discharge tray 11 (see FIG. 1) for discharging a sheet on which an image is formed is provided. On the left side wall portion 1A (see FIG. 1) of the four side wall portions of the housing 1, an air intake port 12 (see FIG. 1) for taking in outside air is provided.

[0018] The sheet conveyance unit 2 conveys a sheet on which an image is to be formed.

[0019] As shown in FIG. 2, the sheet conveyance unit 2 includes a paper feed cassette 21, a paper feed unit 22, a sheet conveyance path 23, and a plurality of conveyance rollers 24.

[0020] The paper feed cassette 21 accommodates sheets on which images are to be formed. For example, the paper feed cassette 21 accommodates sheets such as paper, coated paper, postcards, envelopes, and OHP sheets.

[0021] The paper feed unit 22 takes out sheets one by one from the paper feed cassette 21 and feeds the taken-out sheets to the sheet conveyance path 23.

[0022] The sheet transport path 23 is a passage through which sheets move from the paper feed cassette 21, through the image forming position by the image forming unit 3, to the paper output tray 11.

[0023] Multiple transport rollers 24 are arranged in a line along the sheet transport path 23. Each transport roller 24 transports a sheet in the transport direction D4 (see Figure 2) toward the output tray 11.

[0024] The image forming unit 3 forms an image on the sheet being transported by the sheet transport unit 2.

[0025] As shown in Figure 2, the image forming unit 3 comprises a photoreceptor drum 31, a charging device 32, a light scanning device 33, a developing device 34, a toner container 35, a transfer device 36, a cleaning device 37, and a fixing device 38.

[0026] The photosensitive drum 31 is rotatably mounted in the direction of the arrow shown in Figure 2.

[0027] The charging device 32 charges the circumferential surface of the photoreceptor drum 31.

[0028] The optical scanning device 33 irradiates the circumferential surface of the photoreceptor drum 31, which has been charged by the charging device 32, with light based on the image data. The optical scanning device 33 forms an electrostatic latent image on the circumferential surface of the photoreceptor drum 31.

[0029] The developing device 34 develops the electrostatic latent image formed on the circumferential surface of the photoreceptor drum 31 using toner. The developing device 34 includes a pair of stirring rollers for stirring the developer containing toner, and a developing roller for supplying toner to the photoreceptor drum 31. The pair of stirring rollers and the developing roller are housed in a housing 34A (see Figure 2). The developing device 34 forms a toner image on the circumferential surface of the photoreceptor drum 31.

[0030] The toner container 35 supplies toner to the housing 34A of the developing device 34.

[0031] The transfer device 36 transfers the toner image formed by the developing device 34 onto the sheet transported by the sheet transport unit 2.

[0032] The cleaning device 37 cleans the peripheral surface of the photoreceptor drum 31 after the toner image has been transferred by the transfer device 36.

[0033] The fuser unit 38 fixes the toner image transferred to the sheet by the transfer unit 36 ​​onto the sheet. The sheet with the toner image fixed by the fuser unit 38 is discharged into the output tray 11.

[0034] The inside of the housing 1 generates heat as the image forming apparatus 100 performs image forming operations. Therefore, the image forming apparatus 100 is equipped with an air cooling unit 4 (see Figure 3) to air cool the inside of the housing 1.

[0035] [Configuration of the air-cooling unit 4] Next, the configuration of the air-cooling unit 4 will be explained with reference to Figures 1 to 6.

[0036] As shown in Figures 3 and 4, the air-cooling unit 4 includes an intake fan 41, a first duct 42, a second duct 43, and a third duct 44.

[0037] The intake fan 41 draws in air from outside the housing 1 (see Figure 1). The intake fan 41 is installed on the left side wall 1A of the four side walls of the housing 1, specifically on the left side D5 (see Figure 1) (an example of the first direction of the present invention) side, which is in the width direction (same direction as the left-right direction D3) perpendicular to the sheet transport direction D4 (see Figure 2). Specifically, the intake fan 41 is installed inside the housing 1, facing the intake port 12. As shown in Figure 3, the intake fan 41 is an axial flow fan that rotates around an axis along the left-right direction D3.

[0038] The first duct 42 guides the air drawn in from outside the housing 1 by the intake fan 41 to the first object to be cooled. The first object to be cooled is the control board of the image forming apparatus 100. In the image forming apparatus 100, the control board is located in the right-facing side D6 (see Figure 3) of the four side walls of the housing 1 (see Figure 1). Therefore, the first duct 42 is formed to extend from the intake fan 41 to the right in the D6 direction.

[0039] The second duct 43 guides the air drawn in from outside the housing 1 by the intake fan 41 to the second cooling target. The second cooling target is the fixing device 38 of the image forming unit 3. In the image forming apparatus 100, the fixing device 38 is located behind the intake fan 41. Therefore, the second duct 43 is formed to extend from the intake fan 41 in the rear direction D7 (see Figure 4).

[0040] The third duct 44 guides the air drawn in from outside the housing 1 by the intake fan 41 to the third cooling target. The third cooling target is the developing device 34 of the image forming unit 3. In the image forming apparatus 100, the developing device 34 is located behind and below the intake fan 41. Therefore, the third duct 44 is formed to extend from the bottom of the intake fan 41 in the rearward direction D7 (see Figure 4). The third duct 44 is an example of a duct of the present invention.

[0041] As shown in Figures 3 and 4, the third duct 44 has an air outlet 51, an extension 52, and a connecting portion 53.

[0042] As shown in Figures 3 and 4, the air outlet 51 is located to the left D5 of the developing apparatus 34 of the image forming unit 3, and opens toward the developing apparatus 34 at a position spaced apart from the intake fan 41 in a direction perpendicular to the left D5 direction.

[0043] As shown in Figures 2 and 3, the developing apparatus 34 has a cooling duct 34B. As shown in Figure 2, the cooling duct 34B forms a long air passage in the left-right direction D3 along the bottom surface of the housing 34A.

[0044] As shown in Figure 3, the air outlet 51 is connected to the cooling duct 34B. Therefore, the air blown out from the air outlet 51 flows to the right (D6) inside the cooling duct 34B. The airflow generated inside the cooling duct 34B cools the bottom surface of the housing 34A.

[0045] The extension portion 52 extends along the left side wall portion 1A (see Figure 1) from the intake fan 41 toward the air outlet 51. As shown in Figure 4, the extension portion 52 extends from the lower part of the intake fan 41 toward the rear D7 along the horizontal plane.

[0046] The connecting portion 53 connects the extended end portion 52A (see Figure 4) of the extended portion 52 to the air outlet 51.

[0047] As shown in Figures 4 and 5, the connecting portion 53 includes a first curved portion 61 and a second curved portion 62.

[0048] As shown in Figures 4 and 5, the first curved section 61 bends downward along the vertical direction from the extended end 52A. For example, the first curved section 61 curves downward from the extended end 52A. Alternatively, the first curved section 61 may bend downward from the extended end 52A.

[0049] As shown in Figures 4 and 5, the second curved section 62 curves to the right D6 (an example of the second direction of the present invention) from the first curved section 61 to the air outlet 51. For example, the second curved section 62 curves to the right D6 from the first curved section 61 to the air outlet 51. Alternatively, the second curved section 62 may bend to the right D6 from the first curved section 61 to the air outlet 51.

[0050] Incidentally, in the configuration having the connecting portion 53, the wind speed AF2 (see Figure 5) blown out from the downstream portion of the extension portion 52 in the extension direction (rear direction D7) of the air outlet 51 is faster than the wind speed AF1 (see Figure 5) blown out from the upstream portion of the extension portion of the air outlet 51. This is because the wind flowing through the inside of the extension portion 52 along the extension direction is guided towards the air outlet 51 by hitting the inner wall surface 53A (see Figure 6) of the connecting portion 53 that intersects with the extension direction.

[0051] In contrast, by increasing the length of the air passage along the leftward direction D5 to the air outlet 51 in the third duct 44, it is possible to suppress unevenness in the air velocity blown out from the air outlet 51. However, increasing the length of the air passage along the leftward direction D5 to the air outlet 51 in the third duct 44 increases the size of the housing 1 in the width direction.

[0052] In contrast, the image forming apparatus 100 according to an embodiment of the present invention makes it possible to suppress unevenness in the wind velocity of the air blown out from the air outlet 51 without increasing the size of the housing 1, as will be explained below.

[0053] Specifically, the third duct 44 includes a guide section 54 as shown in Figures 5 and 6.

[0054] As shown in Figure 5, the guide portion 54 is provided within the connecting portion 53. The guide portion 54 guides a portion of the airflow flowing into the connecting portion 53 to the upstream side in the extension direction of the extension portion 52 at the air outlet 51.

[0055] Specifically, as shown in Figures 5 and 6, the guide portion 54 is provided on the first curved portion 61.

[0056] Furthermore, as shown in Figure 6, the guide portion 54 is a rib provided on the first wall portion 44A (see Figure 6) on the left side D5, which is one of a pair of opposing wall portions in the width direction of the third duct 44. In other words, the guide portion 54 is erected in a wall-like manner on the first wall portion 44A. As shown in Figure 6, the guide portion 54 is formed in a wall-like manner that extends in the extension direction and curves or bends downward. Also, as shown in Figure 6, the guide portion 54 is provided so as to divide the air passage in the first curved portion 61 into two. The guide portion 54 comes into contact with a portion of the airflow flowing into the connection portion 53 (the airflow flowing on the bottom side of the extension portion 52) upstream of the inner wall surface 53A in the extension direction, and guides the airflow to the upstream side in the extension direction of the second curved portion 62. Furthermore, the shape of the guide section 54 and its position in the first curved section 61 should be adjusted so that the wind speed of wind AF1 and the wind speed of wind AF2 are equal.

[0057] Here, the third duct 44 is formed by assembling the second forming member 72 (see Figure 5) to the first forming member 71 (see Figures 5 and 6). Figure 6 shows the first forming member 71 before the second forming member 72 is assembled to it.

[0058] The first forming member 71 forms a portion of the third duct 44, including the first wall portion 44A of the pair of opposing wall portions in the width direction of the third duct 44. The second forming member 72 forms the remainder of the third duct 44, including the second wall portion 44B (see Figure 5), which is different from the first wall portion 44A of the pair of wall portions. As shown in Figures 5 and 6, the first forming member 71 forms the portion of the third duct 44 on the leftward D5 side. Also, as shown in Figure 5, the second forming member 72 forms the portion of the third duct 44 on the rightward D6 side. The second forming member 72 is assembled to the first forming member 71 at the leftward D5 side.

[0059] Furthermore, the guide portion 54 is provided on the first wall portion 44A, and its top portion 54A (see Figure 6) contacts the second wall portion 44B (see Figure 5). In other words, the guide portion 54 supports the second forming member 72, including the second wall portion 44B, from the left side D5 of the second wall portion 44B. This makes it possible to reinforce the strength of the third duct 44.

[0060] Furthermore, as shown in Figure 6, the guide portion 54 has a projection 54B at its top 54A that protrudes to the right (D6), which is the opposite direction to the assembly direction (leftward D5) of the second forming member 72 relative to the first forming member 71. For example, the projection 54B protrudes cylindrically from the top 54A.

[0061] Furthermore, the second wall portion 44B of the second forming member 72 has a fitting hole portion 72A (see Figure 5) into which the protrusion portion 54B fits. For example, the fitting hole portion 72A is formed in a circular shape with a diameter slightly larger than the diameter of the protrusion portion 54B. The fitting hole portion 72A is inserted through the protrusion portion 54B when the second forming member 72 is assembled to the first forming member 71. This positions the second forming member 72 relative to the first forming member 71.

[0062] Thus, the image forming apparatus 100 is provided with a guide section 54 within the connection section 53 that guides a portion of the airflow flowing into the connection section 53 to the upstream side in the extension direction of the air outlet 51. This makes it possible to suppress unevenness in the wind velocity blown out from the air outlet 51 without increasing the size of the housing 1.

[0063] [Differentiation] As shown in Figure 7, the first curved portion 61 may also curve upward along the vertical direction from the extended end portion 52A. In this case, the guide portion 54 should be formed as a wall that extends in the extension direction and curves or bends upward.

[0064] Furthermore, as shown in Figure 8, the connection portion 53 of the third duct 44 may include the third curved portion 63 (an example of the curved portion of the present invention) shown in Figure 8, instead of the first curved portion 61 and the second curved portion 62.

[0065] The third curved section 63 curves to the right D6 from the extended end 52A to the air outlet 51. For example, the third curved section 63 curves to the right D6 from the extended end 52A to the air outlet 51. Alternatively, the third curved section 63 may bend to the right D6 from the extended end 52A to the air outlet 51.

[0066] When the connecting portion 53 includes the third curved portion 63, the guide portion 54 is provided on the third curved portion 63, as shown in Figure 8. The guide portion 54 is a rib provided on the bottom surface of the third curved portion 63. The guide portion 54 is formed as a wall that extends in the extension direction and curves or bends to the right in direction D6.

[0067] Furthermore, the present invention may also be applied to the second duct 43. In addition, the air blown by the duct of the present invention may be a component of the image forming unit 3 that is different from the developing device 34 and the fixing device 38.

[0068] [Notes on the invention] The following is an overview of the invention extracted from the above-described embodiments. Note that each configuration and processing function described below can be selected and combined as desired.

[0069] <Note 1> An image forming apparatus comprising: an image forming unit for forming an image on a conveyed sheet; a housing for housing the image forming unit; an intake fan provided on a side wall of the housing on the first direction side along the width direction perpendicular to the conveying direction of the sheet; an air outlet opening toward the image forming unit at a position on the first direction side of the image forming unit and spaced apart from the intake fan in a direction perpendicular to the first direction; an extension portion extending from the intake fan toward the air outlet along the side wall; and a connecting portion connecting the extension end of the extension portion to the air outlet, the duct for guiding air drawn in from outside the housing by the intake fan toward the image forming unit; and a guide portion provided within the connecting portion for guiding a portion of the airflow flowing into the connecting portion toward the upstream side of the extension direction of the extension portion toward the air outlet.

[0070] <Note 2> The image forming apparatus as described in Appendix 1, wherein the extension portion extends in a direction along the horizontal plane, the connecting portion includes a first curved portion that bends in a direction along the vertical direction from the extension end, and a second curved portion that bends in a second direction opposite to the first direction from the first curved portion to the air outlet, and the guide portion is provided in the first curved portion.

[0071] <Note 3> The image forming apparatus as described in Appendix 1, wherein the extension portion extends in a direction along a horizontal plane, the connecting portion includes a curved portion that bends from the extension end in a second direction opposite to the first direction and reaches the air outlet, and the guide portion is provided in the curved portion.

[0072] <Note 4> The image forming apparatus according to Appendix 2, wherein the duct has a first forming member that forms a part of the duct including a first wall portion of a pair of opposing wall portions in the width direction of the duct, and a second forming member that forms the remainder of the duct including a second wall portion different from the first wall portion of the pair of wall portions and is assembled to the first forming member in a direction along the width direction, and the guide portion is a rib provided on the first wall portion, the top of which contacts the second wall portion.

[0073] <Note 5> The image forming apparatus according to Appendix 4, wherein the guide portion has a projection at its top that protrudes in the direction opposite to the assembly direction of the second forming member with respect to the first forming member, and the second wall portion has a fitting hole into which the projection fits. [Explanation of Symbols]

[0074] 1 cabinet 1A Left side wall 2 Sheet transport section 3 Image forming unit 4. Air-cooled section 11. Paper output tray 12 Intake ports 21 Paper feed cassette 22 Paper feed section 23 Sheet transport path 24 Conveyor Rollers 31 Photoconductor Drum 32 Charging device 33 Optical scanning device 34. Developing equipment 35 Toner Containers 36 Transfer device 37 Cleaning device 38 Fixing device 41 Intake fan 42. Duct No. 1 43. Duct No. 2 44 Third Duct 51 Air outlet 52 Extension 53 Connection part 54 Guide section 61 1st song part 62 2nd song part 63 3rd song part 71 First forming member 72 Second forming member 100 Image forming apparatus

Claims

1. An image forming unit that forms an image on a conveyed sheet, A housing for the image forming unit, An intake fan is provided on the side wall of the housing in the first direction, which is in the width direction perpendicular to the conveying direction of the sheet, A duct having an air outlet that opens toward the image forming section at a position on the first direction side of the image forming section and spaced apart from the intake fan in a direction perpendicular to the first direction, an extension portion that extends along the side wall from the intake fan toward the air outlet, and a connecting portion that connects the extension end of the extension portion to the air outlet, and which guides air drawn in from outside the housing by the intake fan toward the image forming section, A guide portion is provided within the connection portion and guides a portion of the airflow flowing into the connection portion toward the upstream side in the extension direction of the extension portion at the air outlet, An image forming apparatus equipped with the following features.

2. The extension extends in a direction along the horizontal plane, The connecting portion includes a first curved portion that bends in a direction along the vertical direction from the extended end, and a second curved portion that bends in a second direction opposite to the first direction from the first curved portion to reach the air outlet. The guide portion is provided on the first curved portion, The image forming apparatus according to claim 1.

3. The extension extends in a direction along the horizontal plane, The connecting portion includes a curved portion that bends from the extended end in a second direction opposite to the first direction and reaches the air outlet. The guide portion is provided on the curved portion, The image forming apparatus according to claim 1.

4. The duct has a first forming member that forms a part of the duct including a first wall portion of a pair of opposing wall portions in the width direction of the duct, and a second forming member that forms the remainder of the duct including a second wall portion different from the first wall portion of the pair of wall portions and is assembled to the first forming member in a direction along the width direction. The guide portion is a rib provided on the first wall portion, the top portion of which is in contact with the second wall portion. The image forming apparatus according to claim 2.

5. The guide portion has a projection at its top that protrudes in the direction opposite to the assembly direction of the second forming member relative to the first forming member, The second wall portion has a fitting hole into which the protrusion fits. The image forming apparatus according to claim 4.

Images